Colombo Giorgio

Professore Ordinario


Politecnico di Milano
giorgio.colombo@polimi.it

Sito istituzionale
SCOPUS ID: 57203078561
Orcid: 0000-0002-9999-8960



Pubblicazioni scientifiche

[1] Rossoni M., Carulli M., Bordegoni M., Colombo G., Prototyping of an Olfactory Display supported by CFD Simulations, Computer-Aided Design and Applications, 20(1), 174-189, (2023). Abstract
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Abstract: Olfactory Displays are devices used to generate and deliver scented air that is eventually smelled by the users. As the literature reports, their development and evaluation mostly rely on experimental activities based on a “trial-and-error” approach, which prevents a comparative analysis of designed solutions and their technical performances, thus leading to prototypes with low potential to become future products. In this paper, an innovative framework embedding Computational Fluid Dynamics (CFD) simulations for designing, prototyping and testing new Olfactory Displays is proposed. After presenting the framework, the paper illustrates the settings for a multi-phase CFD analysis based on Discrete Particles Modeling for simulating olfactory displays. The design of a new wearable olfactory display is presented, detailing all the steps of the framework. A first architecture is devised, and an initial set of simplified 2D multi-phase CFD simulations has been used to propose possible improvements. A new design has been developed, and a 3D CFD simulation has been run to predict its performance. A set of experiments has been conducted to test the real prototypes and compare the performance with the one predicted by the simulations. The experimental results are in good accordance with the simulations, which have proven their effectiveness in improving the design of the olfactory displays.

Keywords: CFD | Olfactory Display DOI: https://doi.org/ | Rapid Prototyping | Virtual and Physical Prototyping

[2] Pigazzi R., Rossoni M., Colombo G., Embedded Workflow for Functionally Graded Material Fabrication with Multi-material Additive Manufacturing, Lecture Notes in Mechanical Engineering, 1055-1066, (2023). Abstract
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Abstract: Multi-Material Additive Manufacturing technologies enable the fabrication of objects consisting of multiple materials. Among them, Material Jetting allows the designer to control the spatial distribution of the selected materials down to the size of microns, making it suitable for Functionally Graded Materials. Despite this great capability, governing the design complexity unleashed by this class of material is still limited to the current computer-aided tools. The paper aims at investigating how a traditional Boundary representation (B-rep) in the CAD domain, which has been conceived for homogeneous materials, can be adapted to integrate heterogeneous object specifications. A workflow to produce heterogeneous objects, with a focus on Functionally Graded Material Objects, is outlined, from the design of the object geometry with a CAD system to the generation of the machine instructions. The procedure to specify the desired material distribution and to generate the voxels has been embedded in a traditional CAD software, allowing the users to define the specifications of the heterogeneous object interacting with the B-rep entities. Once the material distribution has been defined, a solid voxelization is performed on the geometry and the material composition for each voxel is computed. Finally, the object is sliced and a set of images is generated, informing the printer which material should be deposited at the specific position. A case study to check the feasibility of the proposed workflow has been performed: different specimens varying the voxel size and the deposition pattern have been printed.

Keywords: Additive manufacturing | Heterogeneous objects | Voxel printing

[3] Bertolini M., Mullen M., Belitsis G., Babu A., Colombo G., Cook A., Mullen A., Capelli C., Demonstration of Use of a Novel 3D Printed Simulator for Mitral Valve Transcatheter Edge-to-Edge Repair (TEER), Materials, 15(12), (2022). Abstract
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Abstract: Mitral regurgitation is a common valvular disorder. Transcatheter edge-to-edge repair (TEER) is a minimally invasive technique which involves holding together the middle segments of the mitral valve leaflets, thereby reducing regurgitation. To date, MitraClip™ is the only Food and Drug Administration (FDA)-approved device for TEER. The MitraClip procedure is technically challenging, characterised by a steep learning curve. Training is generally performed on simplified models, which do not emphasise anatomical features, realistic materials, or procedural scenarios. The aim of this study is to propose a novel, 3D printed simulator, with a major focus on reproducing the anatomy and plasticity of all areas of the heart involved and specifically the ones of the mitral valve apparatus. A three-dimensional digital model of a heart was generated by segmenting computed tomography (CT). The model was subsequently modified for: (i) adding anatomical features not fully visible with CT; (ii) adapting the model to interact with the MitraClip procedural equipment; and (iii) ensuring modularity of the system. The model was manufactured with a Polyjet technology printer, with a differentiated material assignment among its portions. Polypropylene threads were stitched to replicate chordae tendineae. The proposed system was successfully tested with MitraClip equipment. The simulator was assessed to be feasible to practice in a realistic fashion, different procedural aspects including access, navigation, catheter steering, and leaflets grasping. In addition, the model was found to be compatible with clinical procedural imaging fluoroscopy equipment. Future studies will assess the effect of the proposed training system on improving TEER training.

Keywords: 3D printing | MitraClip procedure | mitral valve regurgitation | Polyjet | segmentation | simulation-based training | transcatheter edge-to-edge repair

[4] Bertolini M., Luraghi G., Belicchi I., Migliavacca F., Colombo G., Evaluation of segmentation accuracy and its impact on patient-specific CFD analysis, International Journal on Interactive Design and Manufacturing, 16(2), 545-556, (2022). Abstract
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Abstract: Medical image segmentation, especially for biological soft tissues, is an issue of great interest. The aim of this study is to evaluate the segmentation performance of a commercial and an open-source software, to segment aortic root and coronary arteries. 3D printing stereolithography technology was used to generate ground truth models, which were then re-acquired by means of a micro-CT scanner. Measurements from the printed and reconstructed models with both the software were compared, in order to evaluate the level of agreement. In the second phase of this study, Computational Fluid Dynamics (CFD) simulations were conducted, to compare the outputs between the models segmented with the two software. The goal was to understand how differences in the segmentation process propagate in CFD results. Results showed that both software guarantee satisfactory segmentation performance, with average geometrical differences between reconstructed and physical models in the order of a few percentage points. However, when we consider thin details, as a sharp stenotic region, the commercial validated software seems to be more accurate in replicating the real anatomy. We also realized how apparently negligible geometrical differences, varying the employed software, can turn into enormous variations of hemodynamic parameters, such as velocity and wall shear stress, which place in the centre the delicate role the segmentation process holds. This evidence is crucial in the biomedical field and especially in a coronary arteries study, where CFD simulations can be exploited as a starting point for surgery considerations.

Keywords: Additive manufacturing | CFD | Coronary arteries | Digital twins | Segmentation

[5] Berardinucci F., Colombo G., Lorusso M., Manzini M., Terkaj W., Urgo M., A learning workflow based on an integrated digital toolkit to support education in manufacturing system engineering, Journal of Manufacturing Systems, 63, 411-423, (2022). Abstract
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Abstract: Digital modelling of manufacturing systems is experiencing a fast development, but it still shows significant limitations when considering integration and interoperability of enabling technologies. Indeed, there is still a lack of reference integrated workflows to perform the wide span of tasks, ranging from layout configuration and performance evaluations to 3D representations. Commercial software tools are either too complex or expensive to be approached by non-specialists, therefore it is hard to design effective learning activities in manufacturing system engineering. This paper proposes a structured learning workflow based on an open toolkit that takes advantage of a common ontology-based data model to smoothly integrate digital tools for manufacturing system modelling, performance evaluation, and virtual reality representation. After detailing methodologies and digital tools, the proposed workflow is applied to a pilot case in higher education.

Keywords: Digital tools | Learning workflows | Manufacturing systems engineering

[6] Bertolini M., Rossoni M., Colombo G., Additive Manufacturing of a Compliant Multimaterial Heart Model, Computer-Aided Design and Applications, 19(6), 1162-1170, (2022). Abstract
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Abstract: Additive manufacturing technologies are increasingly taking place in the medical field, enabling the creation of graspable patient-specific anatomical models. Because of their potentiality in improving the understanding of complex anatomies and their shown effectiveness for residents' training, devices testing and planning of innovative surgical interventions, 3D printed models have been incorporated also into cardiac surgery and interventional cardiology. To offer valid and reliable support, however, these printed models are often required to be flexible, with an adequate mechanical response, especially when they aim at replicating soft tissues. The goal of this paper is to provide a high-quality and robust template of a patient-specific whole heart model, obtained starting from a Computed Tomography dataset and exploiting a material jetting printer. Due to the significant shape complexity and the variability in compliance featuring the human heart, the selection of the materials have been diversified, taking into account different model wall thicknesses. Thanks to the capability of the material jetting technology, the 3D model of the heart has been printed with two different material assignments, designed to get highly realistic feedback and reduce the gap between the real heart and the printed ones. Eventually, an accuracy evaluation of the printed model has been performed, by means of a laser 3D scanner. Some further considerations about time and costs required to produce the model are part of the paper, together with a discussion about potential areas of improvement, from materials characterization to the need of speeding up and automating the segmentation procedure.

Keywords: Additive Manufacturing | Heart | Material Jetting | Patient-specific Anatomy | Segmentation

[7] Bertolini M., Rossoni M., Colombo G., A Workflow for the Numerical Evaluation of Hemodynamics in a Patient-Specific AAA After Stent-Graft Implantation, Lecture Notes in Mechanical Engineering, 827-835, (2022). Abstract
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Abstract: An Abdominal Aortic Aneurysm (AAA) is a focal dilatation of the abdominal aorta, which if not treated can rupture with catastrophic internal bleeding. Besides open surgery, minimally invasive EndoVascular Aneurysm Repair (EVAR) has gradually taken place in clinical practice. In this paper, a workflow to evaluate the hemodynamic changes in a patient-specific AAA after stent-graft implantation is proposed. After the extraction from Computed Tomography (CT) images of the AAA 3D model, a patient-specific idealized stent-graft was obtained by means of CAD software. Models were then imported into the simulation environment, where a proper mesh was generated. Once calculations were completed, parameters of interest were extracted and a comparison between values before and after stent-graft implantation was conducted. Results show that, as expected, the introduction of the stent-graft makes the flow pattern smoother and more regular, with no vortices. This is because the stent provides a more physiological geometry for the blood flow, without the aneurysm enlargement. Anyway, simulations were conducted in a simplified way, being the main aim of the paper the implementation of the workflow by which parameters of interest can be obtained. As a development, the introduction of more refined boundary conditions, maybe considering data of the real patient, would increase the reliability of the simulations. A further step would be the passage from Computational Fluid Dynamics (CFD) to Fluid-Structure Interaction (FSI) simulations, so considering wall vessel compliance.

Keywords: AAA | CFD | Stent-graft

[8] Urgo M., Terkaj W., Mondellini M., Colombo G., Design of serious games in engineering education: An application to the configuration and analysis of manufacturing systems, CIRP Journal of Manufacturing Science and Technology, 36, 172-184, (2022). Abstract
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Abstract: Higher education has to cope with current trends in digital technologies, in particular in the field of industrial engineering, where digital competencies are required more and more. Digital technologies, combined with serious gaming, offer new opportunities for teaching engineering in higher education, with a twofold objective: 1) offering students a rich and realistic experience exploiting advanced digital tools; 2) supporting and complementing traditional education schemes by increasing participation and involvement via serious gaming, enhanced by digital/virtual technologies. Herein, we present a framework for the design of serious games in engineering education, with a specific focus on the definition of intended learning outcomes and the development of the corresponding game activities. This framework was applied to develop a serious game application for the design and analysis of manufacturing systems. The approach was tested thanks to the cooperation of 60 bachelor engineering students and the results extensively analyzed in both quantitative and qualitative terms.

Keywords: Higher education | Manufacturing engineering | Serious games

[9] Lorusso M., Rossoni M., Carulli M., Bordegoni M., Colombo G., A virtual reality application for 3D sketching in conceptual design, Computer-Aided Design and Applications, 19(2), 256-268, (2022). Abstract
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Abstract: The development of Virtual Reality in a wide range of field, including engineering related applications, has pushed towards the investigation of novel solutions that are able to take advantage of such new possibilities, while possibly trying to seamlessly integrate them within currently established workflows. Regarding conceptual sketching, which commonly represents one of the first activities taking place across Product Design development work-flows, there are examples of applications that allow to shift from the 2D layout of traditional drawing to a fully immersive 3D environment where the user is able to produce strokes in space by means of a set of natural gestures. Despite sounding extremely intuitive, this kind of approach also comes with potential issues: the lack of a supportive surface onto which the user can rely on to produce strokes with a high degree of precision while not feeling tired after prolonged sessions can be problematic. Based on these premises, a new hybrid approach is proposed: the user is still immersed in the Virtual Environment, but is able to make use of a traditional tablet device which lays on a physical desk in order to produce visible strokes in Virtual Reality, while having the possibility to simultaneously manipulate the position and the orientation of the scene thanks to a hand tracking device to break into the third dimen-sion. As designed, the application supports the generation of simple line strokes and few basic commands, but a thorough testing session is still needed to validate the solution and investigate on the necessary improvements.

Keywords: Conceptual design | Product design | Virtual reality

[10] Ronca A., Abbate V., Redaelli D. F., Storm F. A., Cesaro G., De Capitani C., ..., Ambrosio L., A Comparative Study for Material Selection in 3D Printing of Scoliosis Back Brace, Materials, 15(16), (2022). Abstract
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Abstract: In recent years, many research studies have focused on the application of 3D printing in the production of orthopaedic back braces. Several advantages, such as the ability to customise complex shapes, improved therapeutic effect and reduced production costs place this technology at the forefront in the ongoing evolution of the orthopaedic sector. In this work, four different materials, two of them poly(lactic acid) (PLA) and two of them poly(ethylene terephthalate glycol) (PETG), were characterised from a thermal, mechanical, rheological and morphological point of view. Our aim was to understand the effects of the material properties on the quality and functionality of a 3D-printed device. The specimens were cut from 3D-printed hemi-cylinders in two different orientation angles. Our results show that PETG-based samples have the best mechanical properties in terms of elastic modulus and elongation at break. The PLA-based samples demonstrated typical brittle behaviour, with elongation at break one order of magnitude lower. Impact tests demonstrated that the PETG-based samples had better properties in terms of energy absorption. Moreover, 3D-printed PETG samples demonstrated a better surface finishing with a more homogenous fibre–fibre interface. In summary, we demonstrate that the right choice of material and printing conditions are fundamental to satisfy the quality and functionality required for a scoliosis back brace.

Keywords: additive manufacturing | advanced material selection | functional characterisations | orthopaedic back braces

[11] Pozzi A., Puricelli L., Rossoni M., Spadoni E., Carulli M., Bordegoni M., Colombo G., CONTEXT-AWARE INDUSTRIAL ROBOT TESTING: LOW-COST VIRTUAL PROTOTYPING ENVIRONMENT, Proceedings of the ASME Design Engineering Technical Conference, 2, (2022). Abstract
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Abstract: This paper presents a case study regarding the simulation of a robotic workstation to virtually test objects detection and obstacle avoidance. Testing these features inside a virtual environment is useful, especially when human-robot cooperation and interaction are involved. Indeed, it allows users to avoid real dangerous conditions, lowering the possible risks of injuries by the users and cutting down the costs compared to a real testing environment. The work presented here exploits a framework where a virtual environment is connected to a Robot Operating System (ROS) able to simulate the kinematic of the robot and, on the other side, a physical ultrasonic sensor acts as the bridge with the real world. The latter, driven by an Arduino board, allows the virtual robot to recognize static obstacles in the real world, mapping the surrounding environment and computing a suitable trajectory to accomplish the given task. Thanks to the sensing capability, the virtual robot is also able to react to the presence of other obstacles (e.g. humans) entering the workspace at runtime. The seamless connection between the virtual and the physical world makes the framework suitable for the fast testing of new algorithms driving the behavior of the robot when interacting with dynamic environments.

Keywords: Costs | Human robot interaction | Object detection | Ultrasonic applications | Virtual reality

[12] Failla L., Vallesi M., Rossoni M., Colombo G., ONTOLOGY-BASED FRAMEWORK FOR KNOWLEDGE-BASED LIFECYCLE MANAGEMENT OF PRODUCT INFORMATION, ASME International Mechanical Engineering Congress and Exposition, Proceedings (IMECE), 4, (2022). Abstract
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Abstract: One of the major barriers to close the gaps between the academic paradigm of Product Lifecycle Management (PLM) and the actual potentialities offered by modern PLM implementations in industry is represented by the inherent difficulty in the management of product information structured over a formalized product-related knowledge. This is especially true for complex, highly customized and engineer-to-order products. The amount, the complexity and the variability of the information throughout the lifecycle makes the Product Data Management capabilities inadequate to realize the required level of accessibility. Ontologies and Semantic Web Technologies are a promising solution in addressing the aforementioned challenges relevant to PLM. Despite that, ontologies implementations in real industrial applications remain very limited in number and, in any case, either are restricted to specific areas or tackle the issue from a too general point of view. The paper aims to present a generalized approach to structure a product knowledge domain over a general-purpose, agnostic “base” ontology. It has been developed on top of formal model taken from literature, where the knowledge relative to a complex, highly customized and engineer-to-order (ETO) product from Oil & Gas Turbomachinery industry was formalized in an OWL-DL ontology enriched with SWRL rules and reasoning capabilities. To facilitates the interaction and the validation with the formal model, a Graphical User Interface (GUI) has been implemented. It enables the penetration of reasoning-enabled ontologies within industrial mindsets and forms the foundations for future integration of the generated product information layer within industrial PLM ecosystems. Within this context, IT asset used to realize the presented proof-of-concept is described and major challenges encountered during the realization and the way they have been tackled are discussed, together with strengths and limitations associated to the approach.

Keywords: Graphical user interfaces | Information management | Knowledge based systems | Life cycle

[13] Bertolini M., Rossoni M., Colombo G., Operative workflow from ct to 3d printing of the heart: Opportunities and challenges, Bioengineering, 8(10), (2021). Abstract
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Abstract: Medical images do not provide a natural visualization of 3D anatomical structures, while 3D digital models are able to solve this problem. Interesting applications based on these models can be found in the cardiovascular field. The generation of a good-quality anatomical model of the heart is one of the most complex tasks in this context. Its 3D representation has the potential to provide detailed spatial information concerning the heart’s structure, also offering the opportunity for further investigations if combined with additive manufacturing. When investigated, the adaption of printed models turned out to be beneficial in complex surgical procedure planning, for training, education and medical communication. In this paper, we will illustrate the difficulties that may be encountered in the workflow from a stack of Computed Tomography (CT) to the hand-held printed heart model. An important goal will consist in the realization of a heart model that can take into account real wall thickness variability. Stereolithography printing technology will be exploited with a commercial rigid resin. A flexible material will be tested too, but results will not be so satisfactory. As a preliminary validation of this kind of approach, print accuracy will be evaluated by directly comparing 3D scanner acquisitions to the original Standard Tessellation Language (STL) files.

Keywords: 3D printing | Heart model | Patient-specific modeling | Segmentation | Stereolithography

[14] Bertolini M., Brambilla A., Dallasta S., Colombo G., High-quality chest CT segmentation to assess the impact of COVID-19 disease, International Journal of Computer Assisted Radiology and Surgery, 16(10), 1737-1747, (2021). Abstract
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Abstract: Purpose: COVID-19 has spread rapidly worldwide since its initial appearance, creating the need for faster diagnostic methods and tools. Due to the high rate of false-negative RT-PCR tests, the role of chest CT examination has been investigated as an auxiliary procedure. The main goal of this work is to establish a well-defined strategy for 3D segmentation of the airways and lungs of COVID-19 positive patients from CT scans, including detected abnormalities. Their identification and the volumetric quantification could allow an easier classification in terms of gravity, extent and progression of the infection. Moreover, these 3D reconstructions can provide a high-impact tool to enhance awareness of the severity of COVID-19 pneumonia. Methods: Segmentation process was performed utilizing a proprietary software, starting from six different stacks of chest CT images of subjects with and without COVID-19. In this context, a comparison between manual and automatic segmentation methods of the respiratory system was conducted, to assess the potential value of both techniques, in terms of time consumption, required anatomical knowledge and branch detection, in healthy and pathological conditions. Results: High-quality 3D models were obtained. They can be utilized to assess the impact of the pathology, by volumetrically quantifying the extension of the affected areas. Indeed, based on the obtained reconstructions, an attempted classification for each patient in terms of the severity of the COVID-19 infection has been outlined. Conclusions: Automatic algorithms allowed for a substantial reduction in segmentation time. However, a great effort was required for the manual identification of COVID-19 CT manifestations. The developed automated procedure succeeded in obtaining sufficiently accurate models of the airways and the lungs of both healthy patients and subjects with confirmed COVID-19, in a reasonable time.

Keywords: COVID-19 | CT | Lungs | Respiratory system | Segmentation

[15] Redaelli D.F., Barsanti S.G., Biffi E., Storm F.A., Colombo G., Comparison of geometrical accuracy of active devices for 3D orthopaedic reconstructions, International Journal of Advanced Manufacturing Technology, 114(1-2), 319-342, (2021). Abstract
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Abstract: The use of 3D digitizing tools is becoming the base for subject-specific products, such as the orthopaedic production process of orthoses and prostheses. This paper aims at comparing the metrological behaviour of low-cost devices (Kinect 1 and 2 by Microsoft, Structure Sensor by Occipital) and high-resolution active sensors (O&P Scan by Rodin4D, NextEngine Ultra HD, Konica Minolta Vivid 9i, GOM ATOS II 400 and Artec Leo) for the survey of human body parts. A calibrated flat plane and a test-field composed of eight calibrated spheres of different radii and placed at different heights were used to evaluate the standard quality parameters (flatness, probing errors in form and size and the standard deviation) for each device as recommended by the VDI/VDE 2634 guidelines. Subsequently, three different parts of a mannequin were surveyed as samples of human body parts. The results demonstrated the higher accuracy of fixed devices with respect to handheld ones, among which Artec Leo and Structure Sensor provided a satisfying level of accuracy for the orthopaedic application. Moreover, the handheld devices enabled performing a fast reconstruction of the mannequin parts in about 20 s, which is acceptable for a person that has to remain as still as possible. For this reason, the Structure Sensor was further tested with five motion approaches which identified that smooth motion provides the lowest deviation and higher reliability. The work demonstrated the appropriateness of handheld devices for the orthopaedic application requirements in terms of speed, accuracy and costs.

Keywords: 3D metrology | Biomedical applications | Human body 3D reconstruction | Low-cost 3D sensors | Probing error standard deviation | Uncertainty

[16] Failla L., Rossoni M., Vallesi M., Colombo G., ONTOLOGY FOR PRODUCT LIFECYCLE MANAGEMENT IN THE OIL&GAS TURBOMACHINERY INDUSTRY, ASME International Mechanical Engineering Congress and Exposition, Proceedings (IMECE), 6, (2021). Abstract
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Abstract: In the industrial contexts of the digital era, data, information and knowledge should seamlessly flow throughout the product lifecycle, and be available at any time and to any agent acting in the value creation stream. PLM is one of the enabler of this scenario, striving to scale the "cobbler"model - where people, information, resources and processes are perfectly integrated - to modern industrial realities operating with multi-disciplinary teams and world-wide dispersed internal and external resources. Yet, despite many industrial realities has invested in the institutionalization of a PLM system, still approx. 60% of time in the value creation process is wasted in searching and waiting for data, data translation, working with wrong data or reinvention of the existing knowledge. After having analyzed the above scenario in the context of a real big industrial reality operating in the turbo-machinery production for Oil & Gas and Engery markets, the present paper aims to propose a solution introducing a working approach based on the modeling of the knowledge domain relevant to a product and its data model by an OWL-DL ontology, and to present the relevant preliminary results. The final target will be the establishment of an ontology-based domain model as the foundation for a digital, human-machine interoperable, product knowledge and data lifecycle management system to bridge the diverse agents operating in the Product Lifecycle Management.

[17] Mahmood K., Otto T., Kuts V., Terkaj W., Modoni G., Urgo M., Colombo G., Haidegger G., Kovacs P., Stahre J., Advancement in production engineering education through Virtual Learning Factory Toolkit concept, Proceedings of the Estonian Academy of Sciences, 70(4), 374-382, (2021). Abstract
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Abstract: The growing relevance of digitalization in production requires the enhancement of human skills and competences in the field of Information and Communication Technology (ICT). Higher education has to cope with this need by providing the necessary ICT skills to future industrial engineers, so that they have a good understanding of the complexity of industries in the 21st century. This paper presents the conceptual development and testing of a Virtual Learning Factory Toolkit (VLFT) that integrates digital tools used in production management with engineering education. The digital tools integrated into the VLFT can help students to exploit enabling technologies such as simulation and virtual reality in their manufacturing studies and practical projects with industrial companies. Moreover, digital tools were tested by using a structured workflow that consists of different learning activities related to manufacturing system configuration. Students practised the digital tools with the help of use cases in the form of joint learning labs, after which the students’ feedback was collected and analysed.

Keywords: Digital tools | Manufacturing systems | Production engineering | Virtual learning factory

[18] Zefinetti F.C., Vitali A., Regazzoni D., Colombo G., Goalkeeper’s Performances Assessed with Action Cameras Based Mocap System, Advances in Intelligent Systems and Computing, 1206 AISC, 259-266, (2021). Abstract
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Abstract: The research work presents a specific procedure to evaluate the performance of soccer goalkeepers by means of a marker-less motion capture (Mocap) system based on a set of 8 GoPro active cameras. The layout of the sensors and the calibration phase have been defined to be easily replicated and not to interfere with athletes and trainers during the exercises. The proposed solution has been tested in collaboration with goalkeeper coaches, who made available the knowledge about conventional training exercise. The Mocap system has been tested by involving two goalkeepers and a coach. The results have been elaborated and the outcomes have been considered interesting by experts. Furthermore, the adopted technology for motion capture and elaboration could be evaluated for an application to the rehabilitation process of an athlete after an injury, to determine his stage of recovery and the most suitable work to be done.

Keywords: Active camera | Goalkeepers training | Kinematic data analysis | Marker-less motion capture | Outdoor motion capture | Sports technology

[19] Redaelli D.F., Abbate V., Storm F.A., Ronca A., Sorrentino A., De Capitani C., Biffi E., Ambrosio L., Colombo G., Fraschini P., 3D printing orthopedic scoliosis braces: a test comparing FDM with thermoforming, International Journal of Advanced Manufacturing Technology, 111(5-6), 1707-1720, (2020). Abstract
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Abstract: In recent years, 3D printing gained considerable attention in the orthopedic sector. This work evaluates the feasibility of producing orthopedic scoliosis braces by 3D printing, comparing performance and costs with classical thermoforming procedures. Critical parameters, such as manufacture time, mechanical properties, weight, and comfort are carefully considered. Polyethylene terephthalate glycol-modified (PETG) was selected among the several filaments materials present on the market. Printed samples were analyzed with electronic microscope, tensile, and impact tests and compared with thermoformed polyethylene (PE) and polypropylene (PP) samples. Moreover, a cost analysis was carried out for the specific application. The thermoformed brace of a volunteer patient affected by scoliosis was reproduced using reverse-engineering techniques. The model was then printed as a single piece and postprocessed by an expert orthotist. Subsequently, the patient wore the brace in a pilot case to compare comfort and mechanical effectiveness. Results show that the 3D printing fabrication method is able to provide a valid alternative to the current fabrication methods, being also very competitive in terms of costs. The morphological analysis does not show critical defects in 3D printed samples, while the mechanical tests highlighted their anisotropy, with an overall brittleness of PETG samples in the direction orthogonal to the fibers. However, in terms of mechanical stresses, a back brace should never reach the polymer yield stress, otherwise the shape would be modified and the therapeutic effect could be compromised. Finally, the patient reported the perception of improved support and no significant comfort differences compared with the thermoformed brace.

Keywords: 3D printing | FDM | Manufacturing process | Mechanical characterization | Orthopedic scoliosis brace | PETG

[20] Riccardo Pigazzi , Confalonieri C., Rossoni M., Gariboldi E., Colombo G., Ontologies as a tool for design and material engineers, ASME International Mechanical Engineering Congress and Exposition, Proceedings (IMECE), 6, (2020). Abstract
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Abstract: Functionally Graded Materials (FGMs), initially conceptualized in the '80, have recently attracted a great research interest thanks to the advent of additive manufacturing (AM) technologies. AM permits to gradationally varying the spatial composition or porosity inside an object resulting in a corresponding spatial change in material properties. The data about this new class of materials are radically different from the traditional engineering materials and require information about the object geometry. Moreover, traditional methods for product design are not sufficient to represent heterogeneous objects. The full exploitation of these technologies requires the synergy of material science, product modeling and manufacturing domain. Ontologies can play a crucial role for the integration, making the information accessible and understandable to both experts from different domains and machines. In this paper, a prototypical ontology for the characterization of FGM objects is proposed. Firstly, an already existing FGM ontology is analyzed, highlighting shortcomings and possible improvements. Then, the new ontology is proposed, focusing on the classes and relationships for accommodating material knowledge and geometrical information. The core idea, retrieved from the literature on heterogeneous object representation and transposed in an ontological fashion, is based on the mapping between the geometrical 3D space and the n-dimensional material space. After presenting the new ontology, a benchmark case study is described to test the effectiveness of this approach along with some competency questions an engineer might be interested in. The proposed ontology represents a first, crucial building block for a more complex system aiming to support the communication and knowledge sharing among different actors in engineering..

[21] Rossoni M., Regazzoni D., Vitali A., Colombo G., Spandre L., de Caro F., Knee prostheses reverse engineering: A preliminary investigation, Proceedings of the ASME Design Engineering Technical Conference, 9, (2020). Abstract
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Abstract: Total Knee Arthroplasty is one of the most commonly performed orthopedic procedures and it is expected to grow in the next future . In the last past years, computer-assisted procedures represent one of the trends that are transforming the way of practicing medicine. Cornering the Total Knee Arthroplasty, digital models of the joints have been used to carry out simulation of their kinematics and mechanical performance. Whilst for the 3D digital reconstruction of the patient geometry several studies have been conducted, an approximated geometry of the prosthesis has been several times employed, with undeniable consequences on the final results. This paper aims at comparing two non-contact reverse engineering technologies to acquire the shape of femoral components employed for total knee arthroplasty. A high-level device (Konika Minolta Vivid 9i) and a mid-low cost laser (NextEngine) has been compared. For the comparison, a systematic procedure of acquisition and elaboration of the results has been adopted in order to have as unbiased as possible results. The procedure involves the use of the proprietary software of the scanners for the elaboration of the raw data and the meshing procedure has been kept the same for all the models. Since the as-is acquired mesh is of high-resolution, a decimation procedure has been carried out in order to make the 3D models lighter and easier to be handled. Once the decimation procedure has been evaluated comparing the original and the simplified models to one another, the digitalized models have been compared with the measurements taken from a coordinate measuring machines. As a preliminary result, the two lasers seem to be adequate to accomplish the reverse engineering process as required by this application. Of course, the mid-low cost laser would be preferable whether the performance will be confirmed to be (statistically) equal.

[22] Rossoni M., Bolzan P., Colombo G., Bordegoni M., Carulli M., Survey of digital tools for the generation of ideas, Proceedings of the ASME Design Engineering Technical Conference, 9, (2020). Abstract
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Abstract: During the concept phase of the industrial design process drawings are used to represent designer’s ideas. More specifically, the designer’s goal is to put the characteristics of ideas on paper so that they can later act as pivotal points in the development of a project. Sketching is also the ideal tool to continue developing an idea: because it is imprecise, the sketch guarantees a high degree of freedom, allowing for changes to made and new ideas to be added. Another possibility is to translate ideas into sketches on computer tools. This approach can allow the designer to use the created 3D model as the basis for further developing ideas. At the present moment, however, this type of solution is not extensively used by designers during the concept phase. Some researchers have identified technical problems as the reason why these instruments have been unsuccessful on the market, while for others this is related to systems still too rigid to be adapted to the often-diverse needs of designers. The research presented in this position paper aims at analyzing what has so far been understood with respect to the process of generating ideas, their initial representation in the concept phase and the tools that have been developed so far to support this phase. Consequently, a discussion on these themes and some hypotheses from which develop new research lines will be presented.

[23] Lorusso M., Rossoni M., Colombo G., Conceptual modeling in product design within virtual reality environments, Computer-Aided Design and Applications, 18(2), 383-398, (2020). Abstract
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Abstract: Digitalization has already permeated most of the design activities, but in spite of this, the generation of visual representations of concepts in the product design domain still relies on analog tools in real world contexts. Despite immersive 3D technologies, such as Virtual Reality, have become widely available and affordable, most designers still make use of pencils and paper sheets, or their digital counterparts, to sketch their initial ideas on 2D supports. This study aims at investigating the reasons behind the mismatch between the rapid growth of immersive technologies and their scarce adoption in the conceptual design activities. Based on the analysis of the state of the art, a classification of the approaches proposing new ways to conduct conceptual representation of products has been drawn. The geometry representation, i.e. parametric or polygonal, and the interaction methods have been taken as metrics to categorize previous works. Weak connections between the modeling paradigm implemented and the interaction methods, lack of spatial faithfulness, ergonomic concerns and the need for quantitative metrics to compare objectively the data resulting from different testing sessions across the various studies are the main issues identified. In order to get concrete evidence of such thoughts, an experimental session has been devised with users from different backgrounds. They were asked to make conceptual sketches of a computer mouse in a traditional fashion, i.e. with pen and paper, and using two off-the-shelf Virtual Reality applications, based on 3D sketching and 3D sculpting respectively. The results are discussed qualitatively by visually comparing the sketches made by the testers, enriched by information deducted by surveying the users before and after the experiments. By comparing the sketches made by each user with the three procedures, preliminary results indicate that VR systems don't bring dramatic improvements compared to traditional 2D sketching tools. Furthermore, despite being enjoyable, VR systems caused physical fatigue, which is a problem that basically does not affect 2D sketching. Despite the size of the sample cannot provide statistical evidence, the outcomes provided good indications about the technology readiness level of Virtual Reality as a conceptual design tool, paving the way for future research directions.

Keywords: Conceptual design | Product design | Virtual reality

[24] Rossoni M., Fumagalli A., Colombo G., Machine Health State Recognition Through Images Classification with Neural Network for Condition-Based Maintenance, Lecture Notes in Mechanical Engineering, 432-443, (2020). Abstract
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Abstract: A robust machine health state recognition tool is a pillar for condition-based maintenance and Deep Learning approach finds its natural application in such a context. This paper investigates the recognition of machine failures by image classification through a convolutional neural network in a condition-based maintenance environment. The case study involves a refrigerator for large retail establishments. Experimental measures, while the machine is approaching failure, are difficult to be collected, especially in the quantity needed for training and testing the neural network. For this reason, a digital twin of the asset has been created to simulate the behavior of the machine and generate as many data as needed: physically-based models of the machine and failure modes have been included and the simulated behavior has been tuned by using experimental data. Finally, it has been employed to generate signals that, translated into images, test the suitability of the neural network.

Keywords: Condition based maintenance | Digital twin | Image classification | Neural network

[25] Redaelli D.F., Storm F.A., Biffi E., Reni G., Colombo G., A Virtual Design Process to Produce Scoliosis Braces by Additive Manufacturing, Lecture Notes in Mechanical Engineering, 860-870, (2020). Abstract
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Abstract: The present work aims to present the current virtual design process of scoliosis braces and propose an improvement by considering the internal geometry. Starting from the external scanning it is possible to apply only corrections that do not consider the interaction with the human body. For this reason we propose to embed the 3D model reconstruction of the skeleton of the patient from the medical images. This would bring to a better virtual design process that could help avoiding the current need for a physical positive mold. The final goal of such a change is to pass from the current thermoforming production to the use of additive manufacturing. In the paper, we briefly analyze the choice of the most convenient 3D printing technology and the selection of a proper material that can be comparable to the ones used for thermoforming. Finally, a case study is presented to test the assumptions regarding both the design and manufacturing processes.

Keywords: 3D printing | Scoliosis brace | Virtual design

[26] Ariansyah D., Rosa F., Colombo G., Smart maintenance: A wearable augmented reality application integrated with CMMS to minimize unscheduled downtime, Computer-Aided Design and Applications, 17(4), 740-751, (2020). Abstract
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Abstract: The ultimate goal of maintenance managers in any industrial firms is to maximize the uptime of the production assets and to keep the downtime to a minimum. These factors affect the capability of an industry to meet the production deadline while still ensuring the good quality product at minimum production cost. To realize this objective, effective maintenance method and innovative tool are required. Previous study has shown that the growing complexity of current manufacturing technologies will necessitate the increasing competent and trained personnel to resolve quickly the interruptions that occur in the shop floor. However, an efficient repair operation is sometimes difficult to achieve especially when the dysfunctional machine involves various possible problems and the assignment of skilled technician and resources to attend to the failed equipment requires more than just the information reported by the operator concerning what was not functioning on site. Augmented Reality (AR) as one of the emerging technologies in the framework of Industry 4.0 provides a way to accelerate the maintenance process and to minimize the recommissioning of maintenance work due to limited maintenance information provided by the operator. This paper presents the application of AR integrated with CMMS on the emerging computing platform Hololens to demonstrate the potential of this integration to optimize the pipeline of maintenance procedure in order to boost the profitability and competitive advantage of an industrial firm.

Keywords: Augmented reality | CMMS | Downtime | Hololens | Maintenance

[27] Rossoni M., Barsanti S.G., Colombo G., Guidi G., Retopology and simplification of reality-based models for finite element analysis, Computer-Aided Design and Applications, 17(3), 525-546, (2020). Abstract
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Abstract: Reality-based 3D techniques and Finite Element Analysis share the way the object under investigation is discretized. Although their purpose, the generation methods and the quality metrics are different, both of them ground on the concept of mesh. Unfortunately, a mesh derived from a reality-based technique are not suitable to be used in a finite element solver directly. This paper aims at comparing different methods to prepare computational mesh of geometries derived from non-contact reality-based technologies. A benchmark test object has been acquired with different devices, a triangulation laser scanner, a multi-stripe triangulation scanner and a digital camera, and post processed in order to fix artifacts. Then, two different decimation approaches have been used: a triangular simplification and retopology. The acquired geometry, before and after the simplifications, has been compared with a CAD model employed as reference: mean and standard deviation between the nominal and the acquired geometries have been tracked. Finally, a tensile test has been simulated making use of a general-purpose finite element analysis software and the results have been compared with the exact solution.

Keywords: Finite element analysis | Laser scanner | Retopology | Reverse engineering | Structure from motion

[28] Vitali A., Colombo G., Regazzoni D., Rizzi C., Virtual prototyping and physical experimentation of lower limb prosthesis, ACM International Conference Proceeding Series, 111-117, (2019). Abstract
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Abstract: Among rising technology in medical field, methods and solutions of reverse engineering have a high impact as a new possibility for improving the traditional processes to design prosthesis and orthoses. Furthermore, reverse engineering solutions allows managing a big amount of patient's data, which can be also exploited for making the medical assessment during rehabilitation activities more objective and measurable. In particular, innovative technologies permit to manage big amount of data coming from several IT devices in order to better understand the correlation between technical aspects and human factors. These IT devices can be exploited through customized software applications, which are able to combine many data types (e.g. 3D scanners, motion capture systems and pressure sensors). In this research work, the attention is focused on the design of lower limb prosthesis around the digital human model of the patient. We present a virtual platform composed by an ad-hoc developed application for customizing the prosthesis according to patients' life style and medical knowledge as well as for visualizing pressure on patient's limb while evaluating his/her gait in a unique virtual knowledge-guided environment. Such applications are conceived to be usable by non IT experts, and all information are directly visualized on the digital human model of the amputee. The first part of the paper introduces the whole platform to design lower limb prosthesis using low-cost technologies. Then, the virtual gait analysis tool is described. Finally, tests and conclusion are discussed.

Keywords: 3D modelling | Health informatics | Marker-less motion capture system | Pressure data | User centered design

[29] Regazzoni D., Vitali A., Rizzi C., Colombo G., A virtual platform for lower limb prosthesis design and assessment, DHM and Posturography, 733-746, (2019). Abstract
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Abstract: This scientific work aims at developing an innovative virtual platform to design lower limb prosthesis centered on the virtual model of the patient and based on a computer-aided and knowledge-guided approach. The main idea is to develop a digital human model of the amputee to be used by the prosthetist in a full virtual environment in which a platform provides a set of interactive tools to design, configure, and test the prosthesis. This virtual platform permits to design and configure the whole prosthesis, in particular, the 3D model of the assembled prosthesis, crucial to define the prosthesis setup and patient’s walking performance. An ad-hoc computer-aided design system has been developed in house to design the 3D model of the socket according to traditional operations made by technicians during traditional manufacturing process. Moreover, a finite element model has been defined to study the contact between residual limb and socket. The resulting 3D model of the socket can be realized by exploiting multimaterial additive manufacturing technology. Finally, the developed platform also permits to handle contact pressures and patient’s gait data in a unique application through the use of a low-cost motion capture (MOCAP) system. The whole platform has been tested with the help of an Italian orthopedic laboratory. The developed platform is a promising solution to develop the check socket, and the application may be used also for training purpose for junior orthopedic technicians.

Keywords: Low-cost MOCAP system | Lower limb prosthesis | Pressure analysis | Socket design and 3D modeling

[30] Rossoni M., Colombo G., Replicas fabrication by laser scanner and additive manufacturing: A preliminary investigation, ASME International Mechanical Engineering Congress and Exposition, Proceedings (IMECE), 14, (2019). Abstract
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Abstract: This paper presents a preliminary investigation on the workflow that allows to replicate object by using 3D laser scanner and a desktop fused filament fabrication 3D printer. Pitfalls and limitations of those technologies will be pointed out in order to find the bottleneck of the workflow, paying specific attention to what concerns the digital workflow from the acquisition to the generation of the g-code. The findings and conclusions are drawn from a case study that has been carried out using the minimum amount of human intervention, especially during the digital post-processing of the data. The objects under investigation is a broken car door handle. Firstly, it has been digitalized using a 3D laser scanner properly calibrated and set. The accuracy, precision and resolution of the measurement tool have been recorded and the as-is acquired data has been checked against topological errors. The as-is acquired model has been compared with the original geometry. The 3d polygonal mesh has been prepared for being printed: the material, machine and process parameters have been chosen. A simulation of the deposition process to estimate warps and deviation from the nominal geometry was carried out. Finally, the object has been additively manufactured using a desktop Fused Filament Fabrication machine: the printed object has been again compared with the original geometry.

[31] Chekurov S., Niklas K., Rossoni M., Redaelli D.F., Colombo G., Axiomatic design to foster additive manufacturing-specific design knowledge, ASME International Mechanical Engineering Congress and Exposition, Proceedings (IMECE), 14, (2019). Abstract
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Abstract: Axiomatic design has the potential to help designers understand the increased design freedom and limitations of additive manufacturing prior to starting the actual design process. The purpose of this study is to verify the usefulness of Axiomatic Design in the design process of complex additively manufactured components. The article uses a case study involving the design of a non-assembly turbine to demonstrate that Axiomatic Design can be applied as a supportive tool to acquire information on new limitations imposed by additive manufacturing, such as minimum wall thickness and maximum size of parts. The use of axiomatic design is demonstrated by describing the process of decomposition of the non-assembly turbine and examining the suitability of the general design according to the independence axiom. The resulting decomposition chart is subsequently used as a basis by the authors to design individually two competing designs of a turbine. Finally, the information axiom is used to determine the design with the lowest information content according to design (part and support volume), performance (pressure drop) and economic parameters (cost).

[32] Bergonzi L., Colombo G., Redaelli D.F., Lorusso M., An augmented reality approach to visualize biomedical images, Computer-Aided Design and Applications, 16(6), 1195-1208, (2019). Abstract
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Abstract: One of the technologies that is showing the most potential in an always widening range of applications, from entertainment to design and even healthcare, is Augmented Reality (AR). The most defining characteristic of AR consists of the possibility to overlap virtual object to be projected by a dedicated device upon a real environment. Throughout this work, the development of an application for the visualization of medical data in AR environments will be discussed. Nowadays, the most appropriate devices for such applications are Head Mounted Displays (HMDs). Investigating current visualization procedures of medical data deriving from CT or MRI scans, AR tools and features have the potential to streamline common activities, as diagnostic and surgery planning precesses, providing a much more immersive user experience. In this paper, an efiective visualization approach merging these new technologies and biomedical images is proposed. Using a cutting edge HMD device, an application that takes as input CT or MRI scans and gives as output an immersive visualization of patient's internal body structures has been developed. The range of possible use scenarios is very wide. In essence, the goal is to recreate the illusion for the user to be able to see through the patient's skin with no visual distortion, providing a much improved perception of the relative position of the inner body structures. Present techniques make use of DICOM data mostly in the diagnostic stage, whereas it is possible to integrate AR tools within the whole medical workfiow and even to further stages of the disease treatment, including surgery planning and training activities. Additionally, the possibility to connect a multitude of HMD devices together that are able to display the same scene from difierent angles, depending on each own position, opens up to a great variety of collaborative working or learning situations. Although there is still a lot of scope for improvements, the paper details the potential of AR for a medical implementation, outlining specifications needed to evolve into something actually usable in a real-life scenario.

Keywords: Abdominal Aortic Aneurysm | Augmented Reality | Biomedical Data | CT

[33] Rossoni M., Bergonzi L., Colombo G., Integration of virtual reality in a knowledge-based engineering system for preliminary configuration and quotation of assembly lines, Computer-Aided Design and Applications, 16(2), 329-344, (2019). Abstract
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Abstract: Realistic visualization of products is now a must-have for all companies facing worldwide and highly competitive market. Despite Virtual Reality technologies are appealing, its industrial use is still limited to conceptual design and prototyping activities. One of the reason is that generating Virtual Reality (VR) environment is a complex and time-consuming task, especially for complex products or systems. Many technical data are involved in their design and conflguration. A meaningful example is the preliminary conflguration of assembly lines devoted to deliver a quotation to the customer. To be competitive, the quotation should be completed in tight time and contain variants of the conflgured system ranging different costs. Moreover, high-impact and successful quotation goes beyond the merely technical aspect. In this view, the automatic generation of a virtual reality environment can foster the adoption of this technology in industry, since its setup time is short and doesn’t require any skills. In this paper, the integration of a VR module in product conflguration and quotation process is proposed. The framework is a Knowledge-based Engineering (KBE) system that, taken the customer requirements as input is able to automatically generate a bunch of different solutions. Starting from technical data coming from a KBE system, a virtual environment is generated automatically fltting the features of the conflgured solution. Furthermore, the immersivity of the VR scene is enhanced by integrating the animation of the objects, like robots and pallets. After a brief description of the KBE system, the paper details the information is involved in, the implementation of the VR module and its integration within the KBE framework.

Keywords: Assembly line | Knowledge-based engineering | Quotation | Virtual reality

[34] Redaelli D.F., Gonizzi Barsanti S., Fraschini P., Biffi E., Colombo G., Low-cost 3D devices and laser scanners comparison for the application in orthopedic centres, International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences - ISPRS Archives, 42(2), 953-960, (2018). Abstract
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Abstract: Low-cost 3D sensors are nowadays widely diffused and many different solutions are available on the market. Some of these devices were developed for entertaining purposes, but are used also for acquisition and processing of different 3D data with the aim of documentation, research and study. Given the fact that these sensors were not developed for this purpose, it is necessary to evaluate their use in the capturing process. This paper shows a preliminary research comparing the Kinect 1 and 2 by Microsoft, the Structure Sensor by Occipital and the O&P Scan by Rodin4D in a medical scenario (i.e. human body scans). In particular, these sensors were compared to Minolta Vivid 9i, chosen as reference because of its higher accuracy. Different test objects were analysed: a calibrated flat plane, for the evaluation of the systematic distance error for each device, and three different parts of a mannequin, used as samples of human body parts. The results showed that the use of a certified flat plane is a good starting point in characterizing the sensors, but a complete analysis with objects similar to the ones of the real context of application is required. For example, the Kinect 2 presented the best results among the low-cost sensors on the flat plane, while the Structure Sensor was more reliable on the mannequin parts.

Keywords: 3D metrology | Biomedical applications | Low-cost 3D sensors | Resolution | Systematic error

[35] Colombo G., Rizzi C., Regazzoni D., Vitali A., 3D interactive environment for the design of medical devices, International Journal on Interactive Design and Manufacturing, 12(2), 699-715, (2018). Abstract
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Abstract: The effectiveness of custom-made prostheses or orthoses heavily depends on the experience and skills of the personnel involved in their production. For complex devices, such as lower limb prosthesis, a conventional manual approach affects the process at the point that the result is frequently not acceptable at the first trial. The paper presents a computer-aided environment, named socket modelling assistant2 (i.e., SMA 2) , to interactively design the socket of lower limb prosthesis by implementing a set of design rules extrapolated from the traditional development process. The new computer-aided environment has been implemented embracing a low-cost philosophy and using open source libraries to provide a solution affordable also by small orthopaedic laboratories. The system permits to modify and interact with the 3D model of residual limb to create the socket geometric model ready to be manufactured by means of additive manufacturing. SMA 2 embeds medical knowledge related to the device functioning, the conventional process and the way orthopaedic technicians work so that it can be much more reliable and repeatable compared to the conventional process, but still enough similar to it to be accepted by the involved personnel. In the paper, the new 3D design procedure is described in detail, from the acquisition of patient’s data to preliminary and customized modelling, and new geometric tools to perform context–related operations are shown. A case study is used to clarify the way the system works and to provide an example of the outcome.

Keywords: Additive manufacturing | Custom medical devices | Geometric modelling | Interactive design

[36] Vitali A., Regazzoni D., Rizzi C., Colombo G., Extending VTK library to dynamically modify polygonal meshes in medical applications, Computer-Aided Design and Applications, 15(2), 203-210, (2018). Abstract
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Abstract: Rising reverse engineering applications require the use of 3D models based on polygonal meshes and a set of modeling operations to shape the final product. Usually, 3D modeling tools do not exploit existing software development kits for developing custom virtual applications. This approach can be very useful for reverse engineering process in the medical field. The paper describes the software development of local mesh modeling algorithms as an extension of the open source library VTK with the aim of shaping 3D triangulated meshes. Then, a case study has been considered to create virtual modeling tools supporting the design process of custom-fit products and, in particular, of lower limb prosthetic socket for amputees. The application has been tested to design a socket for a patient with an above knee amputation. Results reached so far provide a positive feedback on the quality of the designed process and outcome, mainly thanks to the use of the virtual tools based on the developed software modules for 3D mesh modeling.

Keywords: medical devices | Polygonal 3D modeling | prosthesis design | VTK

[37] Chisci E., Alamanni N., Iacoponi F., Michelagnoli S., Procacci T., Colombo G., Setacci C., Grading abdominal aortic aneurysm rupture risk, Journal of Cardiovascular Surgery, 59(1), 87-94, (2018). Abstract
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Abstract: BACKGROU ND: The aim of this paper was to develop a scoring system to grade the risk of rupture of an abdominal aortic aneurysm (AAA ) in individual patients. METHODS: Computed tomography angiography of an AAA were coupled with computational fluid dynamics (CFD) evaluation performed using open source software (ElmerSolver, Institute of Technology, Espoo, Finland). CFD criteria studied were: Oscillatory Shear Index (OSI ), time averaged wall shear stress (TAWSS ) and residence relative time (RR T) on both two-dimensional (2D) and three-dimensional (3D) models. AAA rupture predictors were analyzed and a scoring system was generated using Arabic numerals for all significant variables in order to grade the individual patient risk of rupture. RESUL TS: There were 143 patients examined. Ninety-one AAA s (18 ruptured AAA s), and 52 had a non-aneurysmal aorta. The 2D OSI was the best CFD criterion following multivariate analysis and RO C curves evaluation. An AAA was deemed respectively at low, moderate, or high risk of rupture, according to whether the risk score was defined as AAA I (total score <2.3), AAA II (2.3-6.5) or AAA III (>6.5). The only protective factor was found in diabetes (OR =0.775; CI: 0.665-0.902). CONCLUSIO NS: The Florence Risk Score for AAA rupture based on this report may be a useful tool to predict AAA rupture. A prospective multicenter registry will need to confirm its validity.

Keywords: Aortic aneurysm abdominal | Rupture | Surgical procedure operative

[38] Rossoni M., Colombo G., Bergonzi L., From customer requirements to detailed design: How do product data change?, ASME International Mechanical Engineering Congress and Exposition, Proceedings (IMECE), 13, (2018). Abstract
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Abstract: Current trends in product development process highlight the increasing adoption of digital data and virtual processes. Nowadays, a huge amount of product data are collected without a clear management strategy and, oftentimes, they dont even cover the whole product development process. A global and integrated planning about information needed to sustain product design process is not a trivial task and, usually, companies underrates this issue. From the perspective of virtualization of processes, and then their automation, the lack of structured knowledge is certainly awful. This paper aims at making a critical analysis how product data evolve throughout the product design or configuration process and how they impact the product development activities. Efficient digital product twin allows companies to vir-tualize processes and leverage their automation, but it is important to understand how the knowledge management should be carried out. Three case studies, directly experienced by the authors, have been investigated analyzing digital data and virtual tools that allow companies to automate the design process, each one bringing a peculiar perspective of the problem.

[39] Regazzoni D., Rizzi C., Vitali A., Colombo G., A method to analyse generic human motion with low-cost mocap technologies, Proceedings of the ASME Design Engineering Technical Conference, 1B-2018, (2018). Abstract
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Abstract: A number of pathologies impact on the way a patient can either move or control the movements of the body. Traumas, articulation arthritis or generic orthopedic disease affect the way a person can walk or perform everyday movements; brain or spine issues can lead to a complete or partial impairment, affecting both muscular response and sensitivity. Each of these disorder shares the need of assessing patient’s condition while doing specific tests and exercises or accomplishing everyday life tasks. Moreover, also high-level sport activity may be worth using digital tools to acquire physical performances to be improved. The assessment can be done for several purpose, such as creating a custom physical rehabilitation plan, monitoring improvements or worsening over time, correcting wrong postures or bad habits and, in the sportive domain to optimize effectiveness of gestures or related energy consumption. The paper shows the use of low-cost motion capture techniques to acquire human motion, the transfer of motion data to a digital human model and the extraction of desired information according to each specific medical or sportive purpose. We adopted the well-known and widespread Mocap technology implemented by Microsoft Kinect devices and we used iPisoft tools to perform acquisition and the preliminary data elaboration on the virtual skeleton of the patient. The focus of the paper is on the working method that can be generalized to be adopted in any medical, rehabilitative or sportive condition in which the analysis of the motion is crucial. The acquisition scene can be optimized in terms of size and shape of the working volume and in the number and positioning of sensors. However, the most important and decisive phase consist in the knowledge acquisition and management. For each application and even for each single exercise or tasks a set of evaluation rules and thresholds must be extracted from literature or, more often, directly form experienced personnel. This operation is generally time consuming and require further iterations to be refined, but it is the core to generate an effective metric and to correctly assess patients and athletes performances. Once rules are defined, proper algorithms are defined and implemented to automatically extract only the relevant data in specific time frames to calculate performance indexes. At last, a report is generated according to final user requests and skills.

[40] Redaelli D.F., Colombo G., Fraschini P., Biffi E., Reni G., Current and future manufacturing of chest orthoses, considering the case of osteogenesis imperfecta, Proceedings of the ASME Design Engineering Technical Conference, 1B-2018, (2018). Abstract
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Abstract: The present paper aims at discussing the current manufacturing processes of chest orthoses, considering patients affected by Osteogenesis Imperfecta (OI) and a possible future scenario. OI is a genetic disease caused primarily by the genes responsible for collagen production. One of the most common symptoms among the groups of living subjects affected by OI is scoliosis, the abnormal deformation of the spine curvature. The non-invasive treatments for realigning the spine consist of both physical exercise and use of chest braces. The latter are strongly patient-dependent devices; thus, the level of customization is high. The production processes can be classified in: traditional, modern and research process. The first one consists of a sequence of manual operations on plaster casts and final orthoses. The modern process integrates CAD/CAM systems for the first phases of virtual 3D modeling and the automation of the cast production using milling robot, but maintaining the second part of the process. The research process considers the introduction of polymer Additive Manufacturing (AM) in substitution to the thermoforming. Advantages and disadvantages related to each process are discussed in relation to the OI problem.

[41] Belkadi F., Colledani M., Urgo M., Bernard A., Colombo G., Borzi G., Ascheri A., Modular design of production systems tailored to regional market requirements: A Frugal Innovation perspective, 51(11), 96-101, (2018). Abstract
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Abstract: Tailoring products for emerging regional markets under a frugal innovation perspective is a strategic opportunity for companies’ competitiveness. However, this entails managing the co-evolution of adapted products and production systems for affordable manufacturing costs. In this paper, a modular design process is proposed to support the configuration of production systems adapted to regional market needs. It includes the matching of product and equipment modules, the line balancing, and the system design into an integrated problem. This modular approach supports the propagation of requirements in the product and system co-design process. The results are demonstrated in an automotive real case study.

Keywords: Assembly system | co-evolution | frugal innovation | Modular approach | system configuration

[42] Bergonzi L., Colombo G., Rossoni M., Furini F., Data and knowledge in IIoT-based maintenance application, ASME International Mechanical Engineering Congress and Exposition, Proceedings (IMECE), 11, (2017). Abstract
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Abstract: Along with increased digitalization, virtualization of processes and automation in industry, Industrial Internet of Things opens for new possible scenarios and business models. The opportunities of this technology rely, among the others, on new way for data and knowledge management. Knowledge Based Engineering (KBE) is greatly considered to support design activities related to digital technologies. The paper aims at analyzing the role of Industrial Internet of Things for supporting maintenance operations and evaluating whether the adoption of data structure and the integration with the KBE system can face the actual gaps and needs. After a brief overview of different technologies for knowledge management, a possible scenario has been identified. It represents the framework within IIoT technologies can be applied. This conceptual environment considers a multilevel structure: local facilities, the whole company, suppliers, retailers and global network have been involved into the analysis. Upon that scenario, how data and knowledge can be mapped and managed for each level have been investigated. Moreover, these data can be used to improve the predictive maintenance model as well as to enhance the design of new products through the acquisition and monitoring of an effective set of parameters. Finally, in order to demonstrate the feasibility of the proposed approach with the use of simulation as well as physical devices, a prototypical application related to the maintenance of refrigerated display cabinets has been developed.

[43] Vitali A., Regazzoni D., Rizzi C., Colombo G., Design and additive manufacturing of lower limb prosthetic socket, ASME International Mechanical Engineering Congress and Exposition, Proceedings (IMECE), 11, (2017). Abstract
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Abstract: Additive Manufacturing (AM) is not only an innovative approach of fabrication but it fosters a new paradigm to design products. The possibility to confer inhomogeneous properties to the product provides an important design key. This paper concerns the design and manufacture of medical devices that require a high level of customization. We focus the attention on lower limb prosthesis and in particular on the prosthetic socket. The proposed method is centered on the virtual modeling of patient's residual limb and the virtual process is highly integrated and the data flow is as fluid as possible. Three main phases can be identified: design, validation and manufacture of the socket. Firstly, the technician uses the Socket Modeling Assistant (SMA) tool to design the socket shape. Then, a numerical simulation is run to check pressure distribution and validate the socket shape. Finally, a multi-material 3D printer is used to build the socket. Preliminary results are presented and conclusions are drawn concerning the challenge of multimaterial 3D printing of the socket.

[44] Colombo G., Furini F., Rossoni M., The role of knowledge based engineering in product configuration, Lecture Notes in Mechanical Engineering, 0, 1141-1148, (2017). Abstract
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Abstract: Digital design and manufacturing are critical drivers of competitiveness but only few companies and organizations have the capability to support digitalization across the whole Product Lifecycle. In several cases the information flow is discontinuous, the roles and the issues are not properly defined, the tools are heterogeneous and not integrated in the company organization. An approach that considers an appropriate data and information organization, an efficient internal organization and the availability of integrated software tools that are implementing the industrial best practices, could innovate important and critical aspect of the industrial processes. This paper gives an overview of the main themes related to Knowledge Management in industrial context, focusing on product configuration process. The current role of the knowledge in product configuration will be discussed. Then, a brief overview on Knowledge-based Engineering will be presented. Regarding Knowledge Based methodology, acquisition and formalization techniques and tools will be analyzed. Finally, an application focused on assembly lines configuration will be presented.

Keywords: Automatic Configuration Process | Knowledge Based Engineering | Knowledge Formalization | Product Configuration

[45] Wang C., Colombo G., Au C., Guest editorial, Journal of Computing and Information Science in Engineering, 16(4), (2016). Abstract
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Abstract: International Conference on Innovative Design and Manufacturing (ICIDM) is the premium conference in design, manufacturing, and innovation. It was held at The University of Auckland in New Zealand in the beginning of 2016. The conference was created in 2011 by merging two leading conferences: The International Conferences on Manufacturing Automation (ICMA) and International Symposium on Digital Manufacturing (ISDM). In response to the call for papers, 220 papers were received on various aspects of design informatics, design theory and methodology, human centric design and manufacturing, product lifecycle management, virtual engineering and virtual manufacturing, additive manufacturing, cloud manufacturing, biomechanism and biomanufacturing, etc. All the papers were assessed by International Program Committee and 156 papers were accepted. Based on the quality of the papers, ten papers were selected and published in this special issue. The papers can be categorized into design optimization, rehabilitation robotics, advanced material, manufacturing engineering, and green supply chain management application.

[46] Colombo G., Facoetti G., Rizzi C., Vitali A., Mixed reality to design lower limb prosthesis, Computer-Aided Design and Applications, 13(6), 799-807, (2016). Abstract
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Abstract: This paper presents a Mixed Reality environment, named Virtual Orthopedic LABoratory (VOLAB), which permits to emulate an orthopedic lab and design lower limb prosthesis, in particular, the socket component. The proposed solution is based on low cost devices (e.g., Microsoft Kinect) and open source libraries (e.g., OpenCL and VTK). In detail, the hardware architecture consists of three Microsoft Kinect v2, Oculus Rift for 3D environment visualization and Leap Motion device for hand/fingers tracking. The software development has been based on the modular structure of the prosthetic CAD system, named Socket Modelling Assistant (SMA) and modules have been developed to guarantee the communication among the devices and the performance. Finally, preliminary tests are illustrated as well as results reached so far and future development.

Keywords: Augmented Interaction | Human body devices | Low Cost Hand-Tracking devices | Mixed Reality | Prosthesis design | Socket Modelling Assistant

[47] Regazzoni D., Vitali A., Colombo G., Rizzi C., Virtual gait analysis tool to test lower limb prosthesis, ACM International Conference Proceeding Series, 57-60, (2016). Abstract
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Abstract: Digital Human Modelling (DHM) is becoming a simple way to study the ergonomic behaviour of devices interacting with the human body. In particular, innovative technologies per- mit to manage big amount of data coming from several IT devices in order to better understand the correlation be- tween technical aspects and human factors. In the medical field DHM can be exploited to combine in a unique applica- tion many data types coming from several inputs (e.g. 3D scan, motion capture). In this research work, the attention is focused on the design of lower limb prosthesis around the digital human model of the patient. We present an appli- cation, which allows visualizing pressure on patient's limb while evaluating his/her gait in a unique virtual knowledge- guided environment. Such application is conceived to be usable by non IT experts, and all information are directly visualized on the digital human model of the amputee. The first part of the paper describes the platform to design lower limb prosthesis with particular attention on the use of low- cost technologies. Then, the virtual gait analysis tool is described. Finally, tests and conclusion are discussed.

Keywords: Digital human modelling | Gait analysis | Lower limb prosthesis | Pressure mapping

[48] Serafini M., Furini F., Colombo G., Rizzi C., Optimized development: defining design rules through product optimization techniques, Computer-Aided Design and Applications, 13(5), 600-609, (2016). Abstract
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Abstract: In recent years, parametric optimization has become an important part of product development, allowing the designer to explore an unprecedented number of product configurations. However, optimization is often thought of as the last step of the design process; the product has already been defined and the designer aim is toward the optimization of its performance. At this stage, the main performance trade-offs have been set and cannot be solved by the optimization. We propose an early application of optimization techniques during the product embodiment phase; aimed not at finding the optimal configuration of an existing product, but at highlighting trade-offs and the effect of design variables on the product performance. The output of the proposed procedure is a set of design guidelines that describe the design challenges at an early stage, when there is still time to address trade-offs, and, possibly, resolve them before the final, and more classical, product optimization. The procedure has been tested on two exemplary case studies pertaining to food product refrigeration: a refrigerated display unit and a cabinet shelf.

Keywords: design guidelines | Embodiment design | Optimization

[49] Furini F., Rossoni M., Colombo G., Knowledge based engineering and ontology engineering approaches for product development: Methods and tools for design automation in industrial engineering, ASME International Mechanical Engineering Congress and Exposition, Proceedings (IMECE), 11, (2016). Abstract
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Abstract: The study illustrated in this paper aims at analyzing the knowledge management issue related to product development. Especially, the focus is on the domains in which Knowledgebased Systems (KBE) and Design Automation (DA) tools could be adopted. In the past various studies, a lot of KBE and DA systems have been developed in multiple fields such as automotive, aerospace, energy, materials and manufacturing: the information treated in these studies are about data relatives to specific design, for example, of automotive engine components, aircraft structures, energy plants, advanced material and manufacturing or assembly lines. In all of these domain the organization and formalization of the knowledge is a critical issue. The adoption of a good strategy to manage data and information relative to products and processes involves benefits in the product development process. Different methodologies are described in literature. The two of the most used are the Object-Oriented (OO) and Ontology Engineering (OE) approaches. The former is one of the most common and adopted in the industrial domain, including a lot of implementations in the recent past years. The latter is more commonly used in other fields, like bio-engineering, used with the scope of management of experimental data; few implementation in industrial engineering have been considered. The article considers a brief description of the state of the art about Knowledge Based Engineering and Ontology Engineering. A case studies will be described and the benefits and disadvantages due to the use of the different methodologies will be discussed.

[50] Colombo G., Comotti C., Redaelli D.F., Regazzoni D., Rizzi C., Vitali A., A method to improve prosthesis leg design based on pressure analysis at the socket-residual limb interface, Proceedings of the ASME Design Engineering Technical Conference, 1A-2016, (2016). Abstract
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Abstract: This paper presents a methodology and tools to improve the design of lower limb prosthesis through the measurement of pressure analysis at the interface residual limb-socket. The steps of the methodology and the design tools are presented using a case study focused on a transfemoral (amputation above knee) male amputee. The experimental setup based on F-Socket Tekscan pressure system is described as well the results of some static loading tests. Pressure data are visualized with a colour pressure map over the 3D model of the residual limb acquired using an optical low cost scanner, based on MS Kinect. Previous methodology is useful to evaluate a physical prototype; in order to improve also conceptual design, the Finite Element (FE) Analysis has been carried and results reached so far have been compared with experimental tests. Pressure distributions are comparable, even if some discrepancies have been highlighted due to sensors placements and implemented FE model. Future developments have been identified in order to improve the accuracy of the numerical simulations.

[51] Furini F., Rai R., Smith B., Colombo G., Krovi V., Development of a manufacturing ontology for functionally graded materials, Proceedings of the ASME Design Engineering Technical Conference, 1B-2016, (2016). Abstract
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Abstract: The development of manufacturing technologies for new materials involves the generation of large and continually evolving volumes of data. The analysis, integration and management of these data, typically stored in multiple independently developed databases, creates significant challenges for practitioners. Strategies which allow open sharing of pre-competitive data pertaining to engineering design can play a powerful role in enabling innovation, but these strategies can work only if the data themselves can be presented in a way that is both consistent and understandable to both humans and computers. We believe that ontology applied to engineering (OE) represents a viable strategy for the alignment, reconciliation and integration of diverse and disparate data. The scope of OE includes: consistent capture of knowledge pertaining to the types of entities involved; facilitation of cooperation among diverse groups of experts; effective and flexible ongoing curation and update of data; and collaborative design and knowledge reuse We propose as case study an ontology for the domain of composite materials focusing in particular on the class of 'Functionally Graded Materials' (FGM) with examples drawn from the field of biomedical applications. The goal of the ontology is to provide information about the components of such materials, the manufacturing processes involved in their creation, and their applications, ranging from additive manufacturing to restorative dentistry. The ontology is developed using Basic Formal Ontology (BFO) and parts of the Ontology for Biomedical Investigation (OBI) and follows the best practice principles for ontology development codified in the OBO (Open Biomedical Ontologies) Foundry.

[52] Rossoni M., Colombo G., Furini F., Ascheri A.E., Ippolito M., Assembly line balancing and configuration: An alternative approach for design and planning, Proceedings of the ASME Design Engineering Technical Conference, 1B-2016, (2016). Abstract
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Abstract: One of the most important factors that allows the big enterprises to be competitive in the market is the capability to develop products that are tailored on the specific customer requirements with a short lead-time. This research aims to study an automated configuration tool for assembly lines. A KBE approach was used. The configuration process for an assembly line has been identified with the experts of a big manufacturing Italian company. One of the critical issue is that the domains knowledge is mostly tacit. The implementation stage was carried out with a commercial development tool. Thanks to a modular design of the KBE system a strong but flexible framework was achieved. The rules and data repositories, as well as the code of the single module, can be update easier. An industrial case study was used to validate the proposed approach: the configuration of a cylinder head assembly line was performed.

[53] Ascheri A.E., Furini F., Colombo G., Atzeni E., Ippolito M., A knowledge-based framework for automated layout design in an industrial environment, International Journal of Computer Applications in Technology, 54(3), 171-183, (2016). Abstract
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Abstract: Technical knowledge and experience are intangible assets crucial for competitiveness. Knowledge is particularly important when it comes to complex design activities such as the configuration of manufacturing systems. The preliminary design of manufacturing systems is subject to a huge variability of inputs and outputs and involves decisions which must satisfy many competing requirements. This early engineering phase relies mostly on experience of designers and engineers and is associated with long lead times and high probability of mistakes. Knowledge-Based Engineering (KBE) and knowledge representation techniques are considered to be a successful way to tackle this design problem at an industrial level. This paper presents a methodology to support the configuration of powertrain assembly lines, reducing design times by introducing a best practice for production systems provider companies. The methodology is developed in a real industrial environment, introducing the role of a knowledge engineer. The approach includes extraction of existing technical knowledge and implementation in a knowledge-based software framework. The framework is then integrated with other software tools allowing the first phase design of the line including the line technical description and a 2D and 3D CAD line layout. The KBE application is developed and tested on a specific powertrain assembly case study for which existing knowledge is collected, formalised, implemented in the application and integrated with existing tools. Finally, the paper presents a first validation among design engineers, comparing traditional and new approaches and estimating a cost-benefit analysis useful for future possible KBE implementations.

Keywords: Design automation | Knowledge acquisition | Knowledge-based engineering | Powertrain assembly lines

[54] Colombo G., Facoetti G., Rizzi C., Automatic below-knee prosthesis socket design: A preliminary approach, Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), 9745, 75-81, (2016). Abstract
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Abstract: In this work we present a preliminary study on a system able to design automatically sockets for lower-limb prosthesis. The socket is the most important part of the whole prosthesis and requires a custom design specific for the patient’s characteristics and her/his residuum morphology. The system takes in input the weight and the lifestyle of the patient, the tonicity level and the geometry file of the residuum, and creates a new model applying the correct geometric deformations needed to create a functional socket. In fact, in order to provide the right fit and prevent pain, we need to create on the socket load and off-load zones in correspondence of the critical anatomical areas. To identify the position of such critical areas, several neural networks have been trained using a dataset generated from real residuum models.

Keywords: CAD | Lower limb prosthesis | Neural network | Prosthetic socket

[55] Colombo G., Comotti C., Regazzoni D., Rizzi C., Vitali A., Visual representation of dynamic pressure map on the digital human model of patient with a lower limb prosthesis, Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), 9745, 140-149, (2016). Abstract
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Abstract: The socket for lower limb prosthesis is the central element of artificial leg that needs to be optimize with the aim to increase comfort and reduce pain. Nowadays, the modeling of this part is completely manual and based on prosthetist skills. The key parameter determining if the socket is properly designed is the pressure distribution in the interface between the skin of residual limb and the internal surface of the socket. In this paper, we expose a method to measure this pressure thought resistive pressure sensors and we illustrate a case study of a transfemoral amputee patient. A visualization tool has been developed to dynamically show pressure data on the 3D model of the residual limb during topic moments of the gait by a color scale. Achieved results and future work will be discussed in the paper.

Keywords: Gait | Lower limb prosthesis | Pressure mapping

[56] Colombo G., Regazzoni D., Rizzi C., A methodology for virtual assessment of product ergonomics, International Journal of Computer Aided Engineering and Technology, 8(1-2), 125-143, (2016). Abstract
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Abstract: This paper presents a method, which integrates digital human models (DHM) and virtual prototyping techniques to analyse ergonomic issues of devices to be used by workers. It is based on the comparison between the analysis of AS-IS and TO-BE scenarios with the aim of assessing design concepts, highlighting improvements or worsening and residual deficiencies to be faced. In particular, this paper refers to the case study of display units for groceries or supermarkets. Actually, workers who are in charge of filling the shelves perform highly repeated tasks, potentially dangerous for their health. The AS-IS and TO-BE analysis compares the actual practices with a new scenario in which workers are provided with lifting platforms to load the shelves. The method allows assessing several ergonomics parameters; in this study posture and fatigue are the most relevant. The results achieved with the simulations permitted to propose alternative solutions. Future works in this field concern the standardisation of domain dependant actions virtual human are asked to perform.

Keywords: Design validation | DHM | Digital human models | Display unit | Ergonomics analysis | Fatigue | Lifting AIDS | NIOSH | OWAS | Posture

[57] Bartesaghi S., Colombo G., Morone S., Spatial augmented reality and simulations to improve abdominal aortic aneurysm diagnosis and monitoring, Computer-Aided Design and Applications, 12(6), 803-810, (2015). Abstract
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Abstract: In this work we propose an approach based on IT tools to improve all the clinical activities related to Abdominal Aortic Aneurism (AAA) detection and treatment. In particular, the approach is focused on a 3D CAD model of the AAA and CFD simulations to improve diagnosis by evaluation of rupture risk indicators and Spatial Augmented Reality (SAR) to simulate endovascular repair (EVAR) of the pathology. Geometric model of the vascular wall is build from Computer Tomography (CT) data by using and customizing algorithms and tools implemented in Vascular Modeling ToolKit (VMTK) software library. Four methodologies of geometry initialization are compared and we choose those able to describe the vascular disease excluding any foreign tissue (i.e., bones, internal organs, and muscles). An evaluation of the problems connected to the relative parameters of reconstruction, their influence for the correct geometry representation, focusing the attention on segmentation level and the smoothing of the surface, are presented. In particular, we point out the effect of the smoothing by the use of the Hausdorff distance. We propose a standardized process able to guide users in the modeling of this type of vessels; moreover, SAR can dramatically improve the efficacy of AAA visualization for some different clinical aspects. The 3D geometry of the AAA can be used to carry out CFD analysis, to calculate parameters of the blood flow and evaluate the rupture risk indicator, like Oscillatory Shear Index (OSI). The availability of risk indicators facilitates the physician in the diagnosis and prognosis. Finally, we present a methodology and tools to simulate EVAR on a specific patient based on geometry reconstruction and CFD simulations; this type of procedure can effectively improve training and facilitate endovascular surgery.

Keywords: Abdominal aortic aneurysm | CFD | Computer-aided diagnosis | Spatial augmented reality

[58] Colombo G., Facoetti G., Rizzi C., Vitali A., Simplynurbs: A software library to model nurbs for medical applications, Computer-Aided Design and Applications, 12(6), 794-802, (2015). Abstract
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Abstract: Custom-fit products, such as artificial prostheses, often require the development of hoc modeling tools and procedures. In such a context, this paper describes an open source library, named Simply NURBS, developed for NURBS modeling in medical and health-care domains. This new suite makes available a development kit that integrates the key features of existing open source libraries and new ones to fulfill the requirements of the considered domain. First, the paper introduces the library requirements with particular attention to the prosthetic field as well as pros and cons of current NURBS modeling libraries (both commercial and open sources). Then, the software architecture of Simply NURBS and the basic libraries (e.g., OPENCASCADE and NURBS++) used for its implementation are illustrated enhancing differences and improvements. Finally, a socket modeling tool, named Virtual Socket Laboratory (VSL) developed using SimplyNURBS is described as well as results of tests carried out to evaluate the new system performances.

Keywords: Nurbs | Open source libraries | Prosthetic socket

[59] Colombo G., Bartesaghi S., Pallares E., A method to design custom-fit stent graft for Abdominal Aortic Aneurysm, ASME International Mechanical Engineering Congress and Exposition, Proceedings (IMECE), 3-2015, (2015). Abstract
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Abstract: Abdominal Aorta Aneurysm (AAA) affects aorta, especially above the iliac bifurcation where the Wall Shear Stress (WSS) is greater. Consequence may be fatal in case of breakage; a way to treat it is Endovascular Aneurysm Repair (EVAR) where a stent graft is placed inside the aorta without open surgery requirement. Because of the standards, stent graft can be chosen between several sizes: in some cases, this device cannot fit perfectly with the anatomy of the patient and this can lead to a not optimal behavior of the prosthesis and further complications. This study present a method to design and test specific custom-fit stent graft able to better adapt to the patient artery improving the efficiency of the prosthesis and reducing the risk of the migration of the graft as well as the fabric torn. The design method is based on a 3D geometric model of the aorta, generated from CT scan data. Centrelines and geometric data for cross sections along the aorta are the inputs necessary to define the mesh of the stent. A custom algorithm is developed to size the stent in relation to the geometric data of the specific patient; when the frame of the prosthesis is defined, a CAD-based Loft Surface has used to define surfaces between the stent rings. For the bifurcation, again CAD-based Boundary Surfaces is used. The described procedure has been also applied in a Augmented Virtual Reality simulation of the EVAR and, finally, it permits a CFD simulation to evaluate the behavior of the prosthesis inserted into the aorta.

[60] Furini F., Ascheri A., Colombo G., Ippolito M., Atzeni E., Configuration rules for assembly line layouts: An integrated approach for the preliminary design, ASME International Mechanical Engineering Congress and Exposition, Proceedings (IMECE), 11-2015, (2015). Abstract
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Abstract: The design and the configuration of manufacturing systems, such as assembly lines layouts, are time consuming activities, mainly based on implicit knowledge and no definite rules. This complicated design process is associated with high costs, long lead times and high probability of risks and reworks. Knowledge Based Engineering (KBE) is a technique that can tackle these issues and support the engineers in the early design steps of a manufacturing system with a comprehensive and systematic approach, into the integrated design in a complex system and its related processes. The purpose of this research involve the use of KBE methodology in order to collect and formalize knowledge about the a case study, the design of an assembly line layout system for the cylinder head valve of a car engine. With the formalization of the case study is possible to create an application of configuration that supports the decision making process during the preliminary design phase. The possibility to extend the process to a multi objective optimization is considered. The method ology should be able to help manufacturing equipment providers to shrink design times, evaluating more alternatives and integrating different activities related to the preliminary design phase of a system. This research proposes a practical approach combining the current research state of the art and a real industrial environment for knowledge extraction and application.

[61] Colombo G., Rizzi C., Facoetti G., Vitali A., Automatic generation of software interfaces for hand-tracking devices, Proceedings of the ASME Design Engineering Technical Conference, 1B-2015, (2015). Abstract
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Abstract: This paper presents a software module, named tracking plug-in, developed to automatically generate the source code of software interfaces for managing the interaction with low cost hand-tracking devices (e.g., Leap Motion and Intel Gesture Camera) and replicate/emulate manual operations usually performed to design custom-fit products, such medical devices and garments. The proposed solution is based on the Eclipse platform, a free integrated development environment (IDE), that allow us to manage the automatic code generation in a simple way after having defined the target application using a meta-model language, in our case the UML class diagram. First, we describe the background as well as the main problem, then, the software solution and adopted tools (i.e., Eclipse and Acceleo). Finally, the preliminary tests carried out for two applicative contexts (prosthetic and textile/clothing) are presented.

[62] Colombo G., Facoetti G., Rizzi C., Vitali A., Low cost hand-tracking devices to design customized medical devices, Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), 9179, 351-360, (2015). Abstract
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Abstract: This paper concerns the development of a Natural User Interface (NUI) for lower limb prosthesis design. The proposed solution exploits the Leap Motion device to emulate traditional design tasks manually performed by the prosthetist. We first illustrate why hand-tracking devices can be adopted to design socket of lower limb prosthesis using virtual prototyping tools. Then, we introduce the developed NUI and its features mainly with regards to ergonomics and ease of use. Finally, preliminary tests are illustrated as well as results reached so far.

Keywords: Augmented interaction | Hand-tracking devices | SMA

[63] Colombo G., Facoetti G., Rizzi C., Vitali A., Automatic identification of below-knee residuum anatomical zones, Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), 9185, 327-335, (2015). Abstract
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Abstract: The research work presented in this paper is part of an innovative framework that deals with the design process of lower limb prostheses. The quality of the whole prosthesis depends on the comfort of the socket, which realizes the interface between the patient body and the mechanical parts. We developed a CAD system, named Socket Modelling Assistant that guides the user during the design of the socket, exploiting domain knowledge and design rules. In this work we present a preliminary study that describes the implementation of a software module able to automatically identify the critical areas of the residuum to adequately modify the socket model and reach the optimal shape. Once the critical areas have been identified, the Socket Modelling Assistant can apply proper geometry modifications, in order to create the load and off-load zones for a good pressure distribution over the residual limb.

Keywords: CAD | Lower limb prosthesis | Neural network | Prostheses socket

[64] Regazzoni D., Rizzi C., Colombo G., The role of virtual ergonomic simulation to develop innovative human centered products, Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), 9185, 74-83, (2015). Abstract
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Abstract: The paper concerns the use of integrated methodologies and tools to perform innovative human centered development of products. Digital simulation of ergonomics by means of DHM is shown together with advanced tools for design, taking into account Knowledge-based systems, Design Automation and design of highly customized goods. Two different applications of the proposed approach are described, the first refers to an industrial product, the second to the medical domain. Both applications, even if belonging to completely different fields benefit from putting the human at the center of the developing paradigm from the very first step of product development. Some results and discussion highlight benefits and limitation of the approach and of the adopted tools.

Keywords: Design Automation | Digital human modelling | Ergonomics | Human centered design | Knowledge-based systems | Lower limb prosthesis

[65] Colombo G., Morotti R., Regazzoni D., Rizzi C., An approach to integrate numerical simulation within KBE applications, International Journal of Product Development, 20(2), 107-125, (2015). Abstract
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Abstract: This paper presents an approach to automate and integrate numerical simulations within knowledge-based engineering applications to improve the use of simulation tools, especially in small and medium enterprises. Main discussed issues concern: (a) the importance of the CAD model as an input of the process, (b) data migration from CAD to CAE tools, (c) model characterisation, (d) effects of parameters variations, (e) simulation steps, and (f) results evaluation. In addition, formalisation and representation of rules and procedures to automate the design process, in particular the simulation tasks, are presented. Two case studies are described to explain and verify the approach. The first case concerns the design process of centrifugal industrial fans, during which simulation tools are used to verify the correct sizing of impeller blades. The second one is related to a non-industrial process; actually, it regards a medical device, and more precisely lower limb prosthesis. Finally, main results are discussed.

Keywords: Embedded simulations | Industrial fan | KBE | Knowledge-based engineering | Simulation rules | Socket design

[66] Ascheri A., Colombo G., Ippolito M., Atzeni E., Furini F., Feasibility of an assembly line layout automatic configuration based on a KBE approach, Proceedings of the 2014 International Conference on Innovative Design and Manufacturing, ICIDM 2014, 324-329, (2014). Abstract
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Abstract: Design of assembly lines is a knowledge intensive process relying significantly on experience of designers and engineers, lessons learned and complex sets of rules. This complicated design process is associated with high costs, long lead times and high probability of risks and reworks. Knowledge Based Engineering (KBE) and knowledge representation techniques are considered to be a successful way to tackle this design problem. This paper presents a methodology to support the configuration of assembly lines, mitigating risks and costs by introducing a best practice for global production systems provider companies. A set of system engineering rules is extracted from interviews and domain best practices and knowledge about product domain and design process is formalized. These rules will be implemented in a user-friendly platform allowing the design of first phase line layout by taking the defined system requirements (e.g. cycle time) as input. Then, the KBE approach is extended to a specific case study taken from the powertrain sector. Here, the collected knowledge on an assembly line and its design process is presented.

Keywords: Assembly Line | Design Automation | Knowledge Based Engineering | Powertrain Systems

[67] Ascheri A., Ippolito M., Colombo G., Furini F., Atzeni E., Automatic configuration of a powertrain assembly line layout based on a KBE approach, 19th IEEE International Conference on Emerging Technologies and Factory Automation, ETFA 2014, (2014). Abstract
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Abstract: Design of assembly lines is a knowledge intensive process relying significantly on experience and associated with high costs, long lead times and high probability of risks and reworks. This paper presents a methodology to support the early stage design of assembly lines through Knowledge Based Engineering (KBE). In this introductory paper the authors discuss the methodology to implement the KBE approach. A set of system engineering rules is extracted from direct interviews and domain best practices and knowledge about product and process is formalized. These rules will be implemented in a user-friendly platform allowing the design of first phase line layout by taking the defined system requirements (e.g. cycle time) as input. Then, the KBE approach is extended to a specific case study taken from the powertrain sector.

Keywords: Assembly Line | Design Automation (DA) | Knowledge Based Engineering | Powertrain Systems

[68] Facoetti G., Vitali A., Colombo G., Rizzi C., A low cost haptic mouse for prosthetic socket modeling, Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), 8529 LNCS, 508-515, (2014). Abstract
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Abstract: This paper refers to the design of prosthetic socket adopting a computer-aided approach. The main goal is to make available a modeling tool, named SMA-Socket Modeling Assistant, which permits to replicate/emulate manual operations usually performed by the prosthetist. Typically, s/he also relies on the sense of touch; therefore the underlying idea has been to develop and experiment haptic devices. The paper presents a haptic mouse at low-cost to make it affordable also by small orthopedic labs. It is essentially a traditional mouse device enhanced with a servomotor and a pressure sensor pad integrated with Arduino board and SMA. The application within SMA is described as well as the haptic interaction with physically-based model of the residual limb. Finally preliminary tests are illustrated. © 2014 Springer International Publishing Switzerland.

Keywords: Arduino | haptic devices | low cost haptic mouse | prosthesis socket modelling

[69] Bartesaghi S., Colombo G., Knowledge extraction to automate CFD analysis in abdominal aneurysm diagnosis and treatment, International Journal of Information Technology and Management, 13(2-3), 176-201, (2014). Abstract
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Abstract: In the last few years, advanced simulation tools have been tested in academic researches to evaluate the causes and evolution of abdominal aortic aneurysm (AAA). This study describes the activity of knowledge extraction aimed at automating the CFD analysis of an AAA. A simple benchmark geometry is considered. Knowledge and rules extraction are done by comparing: 2D and 3D CFD solutions, results from Newtonian and non-Newtonian formulations, influence of the prism layer and inlet boundary conditions, and numerical solver schemes. A grid refinement study using the verification and validation approach was done. As a result, finer hexahedral meshes with a prism layer near the vessel walls is necessary to capture the velocity gradient and wall shear stress correctly; a simple Newtonian formulation is enough to capture the fluid flow behaviour. A first step in the validation process is taken through the application of the extracted rules on a real patient's specific geometries. © 2014 Inderscience Enterprises Ltd.

Keywords: Aneurysm | CFD | Computational fluid dynamics | Diagnosis | Haemodynamic | Therapy

[70] Morotti R., Rizzi C., Regazzoni D., Colombo G., Numerical simulations and experimental data to evaluate residual limb-socket interaction, ASME International Mechanical Engineering Congress and Exposition, Proceedings (IMECE), 3, (2014). Abstract
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Abstract: This paper presents an automatic simulation procedure to study the stump-socket interaction that has been embedded within a software platform specifically developed to design lower limb prosthesis. In particular, it investigates and compares the results obtained by means of FE tools with the experimental data acquired with pressure transducers. A transfemoral (amputation above knee) male amputee has been considered as case study. Numerical simulations have been carried out considering different techniques to acquire the residuum geometry and different socket models. In details, two residuum geometric models were reconstructed starting from MRI images and from 3D scanning to investigate how acquisition techniques influence the final results. Two socket geometric models were taken into account. The first was the patient's real socket, acquired by 3D scanning; the second one has been modeled using a dedicated CAD system, named Socket Modeling Assistant. The patient's real socket has been also used to perform the experimental pressure measurements. The experimental data have been acquired by means of the Tekscan F-socket system. Results reached so far allowed identifying main criticalities and future developments to improve the accuracy of the numerical results and make available a full-automated simulation procedure.

[71] Furini F., Colombo G., Orlandi M., Multi objective optimization and knowledge based engineering to improve refrigerated display unit design, ASME International Mechanical Engineering Congress and Exposition, Proceedings (IMECE), 11, (2014). Abstract
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Abstract: This paper presents a methodology to automatically design a family of products by integrating Knowledge Based Engineering and multi objective optimization. Methodologies for automatic design are able to dramatically reduce the development time of new models and also ensure a high quality of products. The approach presented here integrates the object-oriented modeling of product and process design with multi-parametric optimization. With this application is possible to define the initial configuration of new models and the optimization techniques may allow the choice and the optimal sizing of the main parts of the new product. To validate the proposed approach, a prototype has been developed for the optimized design of a family of refrigerated display units for commercial use. This paper describes the main aspects of the application considering the gathering of the knowledge, its implementation of this knowledge on automation codes, the description of the multi objective optimization and results achieved so far.

[72] Colombo G., Rizzi C., Facoetti G., Vitali A., A preliminary study of new interaction devices to enhance virtual socket design, Proceedings of the ASME Design Engineering Technical Conference, 1B, (2014). Abstract
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Abstract: This paper presents a research work on the augmented interaction applied to an innovative platform to design lower limb prosthesis, in particular the prosthetic socket. The underlining idea is to experiment low-cost hand-tracking devices, to manipulate the 3D virtual model of the socket using hands as traditional done by the prosthetist. The goal is to make available a modeling tool, named Socket Modeling Assistant-SMA that permits to replicate/emulate manual operations usually performed by the prosthetist during the traditional development process. Two devices have been considered and compared: the Leap Motion device and the Intel Gestures Camera. To this end a set of gestures has been identified to make more natural the interaction with SMA. Preliminary tests and results reached so are described and discussed.

[73] Morotti R., Rizzi C., Regazzoni D., Colombo G., Digital human modelling to analyse virtual amputee's interaction with the prosthesis, Proceedings of the ASME Design Engineering Technical Conference, 1A, (2014). Abstract
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Abstract: This paper refers to the integration of simulations tools to assess the design of prosthetic devices. We address issues arising when the prosthesis needs to be virtually tested, i.e., the gait of the virtual patient wearing the prosthesis. Therefore, we integrate two different simulation tools: the first one to study the interaction between socket and residual limb during the gait and the second one to analyze the patient's gait deviations. Combining these numerical analyses, it is possible to investigate the causes of gait deviations and suggest remedies, both related to the prosthesis setup and the socket modeling. To prove the validity of the approach, we implemented a Finite Element Analysis model to analysis the stump-socket contact and we assembled a low cost Motion Capture system to acquire and elaborate patient gait. Preliminary results and remarks conclude the paper.

[74] Klein P., Pugliese D., Lützenberger J., Colombo G., Thoben K.D., Exchange of knowledge in customized product development processes, Procedia CIRP, 21, 99-104, (2014). Abstract
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Abstract: If Customized Product Development is perceived as developing products that fulfill the customers individual requirements and in parallel reflect production constraints, such as manufacturing capabilities, a direct demand can be derived for solutions to adapt a given design easy and fast to new requirements based upon the companies production knowledge - At best in an automated way. The latter is usually covered by Knowledge Based Engineering systems. KBE systems are capable to automate repetitive engineering tasks, such as the automated calculation of ship structural design. However, while the efficiency of implemented KBE projects is non controversial, the development or modification of an existing KBE solution usually requires substantial investments due to knowledge acquisition, codification and software implementation. In addition most solutions are still case based and not grounded in structural frameworks. Knowledge is often written in a proprietary language; rules and algorithms are not compatible with other KBE-frameworks and are usually not on a level that is comprehensible for the engineers or domain experts. While this may not be crucial for long development cycles, it may become a hurdle in terms of Customized Product Development with its short cycles. In other words, future KBE must support an incorporation of knowledge from different domains and business units. Thus the objective of the paper is to explain the need for a change in collaborative knowledge sharing and re-use in context of KBE. Based upon, the constraints for a KBE related interchange format are drafted. A three layered approach is proposed in order to adequately represent and exchange KBE knowledge. Each layer addresses different levels of abstraction: An upper layer describing just the core knowledge at a glance, a middle layer in order to codify the knowledge on abstract level, but with purpose of software development and a base layer covering the software code itself. Utilizing an independent format for management of KBE knowledge, the users of CAx systems are able to exchange codified knowledge and gain the rationale behind. Hence the full paper attempts to deliver a substantial contribution for the development of systems, which are capable to easily adapt a given design to upcoming user-requirements, while facing the production challenges.

Keywords: Customized product development | Knowledge based engineering | Knowledge engineer | Knowledge mangement | Product development

[75] Colombo G., Pugliese D., Klein P., Lutzemnberger J., A study for neutral format to exchange and reuse engineering knowledge in KBE applications, 2014 International Conference on Engineering, Technology and Innovation: Engineering Responsible Innovation in Products and Services, ICE 2014, (2014). Abstract
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Abstract: In the discipline of Knowledge Based Engineering (KBE), we propose a study for a possible solution to reuse pieces of engineering knowledge that have been already represented in other software tools. Those tools are mainly programs or CAD files, and are usually stored in companies' repositories (databases and PLM systems among the others). For reusing, we mean the possibility of replicating tout-court a specific set of rules, geometry and user interfaces in different projects, software and even application field. In particular, we propose the adoption of a tailored language based on XML syntax, whose taxonomy allows describing the most common aspects of the engineering design process: (1) product architecture descriptions, with their parts relations and design rules; (2) design process descriptions, with the interactions between company's knowledge and products. Thus we propose the Rules Interchange Format (RIF) file to fulfil this achievement. The RIF file is the main output of a specific Work Package in the context of the 'LinkedDesign' European Commission founded project. It is represented by an XML schema where we translated and joined together two of the most common knowledge formalization modelling languages into XML tags: an UML Class Diagram based pattern, to describe products architectures; an IDEF0 Diagram based pattern, to describe design processes. In order to include the description of design automation aspects, to be used with KBE systems, we enriched the mentioned patterns introducing special tags for managing product configuration rules and connections interfaces with CAD tools and PLM. © 2014 IEEE.

Keywords: Customized Product Development | Knowledge Based Engineering | Knowledge Engineer | Knowledge Management | Product Development

[76] Colombo G., Morotti R., Rizzi C., FE Analysis of Contact between Residual Limb and Socket during Simulation of Amputee Motion, Computer-Aided Design and Applications, 11(4), 381-388, (2014). Abstract
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Abstract: The contact pressure at the socket-residual limb interface is the most important parameter to evaluate comfort of leg prosthesis. Experimental works analyzed this parameter for typical postures and during walking of an amputee; but experimental tests require a real prototype of the socket equipped with transducers. To optimize socket design, this work presents a virtual approach based on a digital avatar of the patient wearing lower limb prosthesis. Our approach considers the integration of two different types of simulation: the first one concerns the multi-body gait analysis, the second one the pressure evaluation at the socket-residual limb interface with FE analyses. The paper describes the model used, the simulation tools adopted and their integration. Finally the case study related to patient walking on flat floor is described. © 2014 CAD Solutions, LLC.

Keywords: gait simulation | human modeling | prosthesis design | socket-residual limb contact

[77] Colombo G., Facoetti G., Rizzi C., Vitali A., Zanello A., Automatic 3D reconstruction of transfemoral residual limb from MRI images, Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), 8026 LNCS(PART 2), 324-332, (2013). Abstract
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Abstract: This work is part a new design platform for lower limb prosthesis centered on the patient's digital model and based on the integrated use of virtual prototyping tools. In particular, 3D detailed model of residual limb, that includes not only the external skin but also bones and soft tissues, is needed for socket design and finite element analysis to study the socket-residual limb interaction. In this paper, we present a procedure for 3D automatic reconstruction of the residual starting from MRI images. The output is a 3D geometric model, in a neutral format (IGES), which permits CAD information exchange among the modules composing the design platform. The reconstruction procedure consists of three different phases: image pre-processing, voxel segmentation, 3D models generation. Results have been considered promising and future activities to enhance the algorithm performance have been planned. © 2013 Springer-Verlag.

Keywords: 3D automatic reconstruction | Lower limb prosthesis design | MRI | segmentation

[78] Colombo G., Regazzoni D., Rizzi C., Markerless motion capture integrated with human modeling for virtual ergonomics, Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), 8026 LNCS(PART 2), 314-323, (2013). Abstract
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Abstract: This paper refers to the context of virtual ergonomics and specifically addresses a case study of the commercial refrigeration industry. The aim is to develop a computer-aided platform to analyse end-users' postures and movements and ergonomically validate the design of device a man or woman may deal with. This paper describes the integrated use of human modeling and motion capture (Mocap) systems to perform ergonomic analysis relying exactly on real movements. Two optical Mocap systems, both low cost and markerless, have been considered: one based on six Sony Eye webcams and another one on two Microsoft Kinect sensors. Analogously, two human modeling tools have been adopted: Jack, specifically targeted for ergonomics and integrated with Microsoft Kinect, and LifeMod, a biomechanical simulation package. The proposed virtual ergonomics solutions have been experimented considering the case study of vertical refrigerator display units. © 2013 Springer-Verlag.

Keywords: commercial refrigeration | Digital human modeling | Mocap | Virtual ergonomics

[79] Colombo G., Regazzoni D., Rizzi C., Ergonomic design through virtual Humans, Computer-Aided Design and Applications, 10(5), 745-755, (2013). Abstract
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Abstract: This paper presents a methodological approach to analyze ergonomic issues of equipment specifically designed to load refrigerated display units. The methodology is based on the integrated use of virtual humans and prototyping techniques and on the comparison between the analysis of AS-IS product and TO-BE design concepts to highlight improvements or worsening of the new design and eventual residual deficiencies. In particular, Digital Human Models have been adopted to evaluate different technical solutions for pick and place operations of food items on the display unit shelves according to the specific needs of supermarket operators and to ensure health and hygienic conditions. We first present the state of the art of digital human models and the referring standards for workplace regulations in terms of postures and fatigue. The adopted methodology is described including chosen virtual humans, refrigerated units and handled products. Then, the application of the methodology is described as well as the ergonomics tests and results obtained for the AS-IS and TO-BE solutions. Finally, discussion of results and conclusions are reported. © 2013 CAD Solutions, LLC.

Keywords: Ergonomic design | Refrigerated display unit | Virtual humans

[80] Colombo G., Facoetti G., Rizzi C., A digital patient for computer-aided prosthesis design, Interface Focus, 3(2), (2013). Abstract
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Abstract: This article concerns the design of lower limb prosthesis, both belowand above knee. It describes a newcomputer-based design framework and a digital model of the patient around which the prosthesis is designed and tested in a completely virtual environment. The virtual model of the patient is the backbone of the whole system, and it is based on a biomechanical generalpurpose model customized with the patient's characteristics (e.g. anthropometric measures). The software platform adopts computer-aided and knowledge-guided approaches with the goal of replacing the current development process, mainly hand made, with a virtual one. It provides the prosthetics with a set of tools to design, configure and test the prosthesis and comprehends two main environments: the prosthesis modelling laboratory and the virtual testing laboratory. The first permits the three-dimensional model of the prosthesis to be configured and generated, while the second allows the prosthetics to virtually set up the artificial leg and simulate the patient's postures and movements, validating its functionality and configuration. General architecture and modelling/simulation tools for the platform are described as well as main aspects and results of the experimentation. © 2013 The Author(s) Published by the Royal Society. All rights reserved.

Keywords: Digital patient | Human modelling | Lower limb prosthesis | Virtual prototyping

[81] Colombo G., Facoetti G., Rizzi C., Virtual testing laboratory for lower limb prosthesis, Computer-Aided Design and Applications, 10(4), 671-683, (2013). Abstract
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Abstract: This paper presents an environment, named Virtual Testing Lab-VTL, where the orthopedic technicians can test the prosthesis replicating the traditional procedures. It is part of an innovative design framework centered on digital models of the whole patient or of his/her anatomical districts, which constitute the backbone of the whole prosthesis design process. The virtual lab permits to realize a complete amputee's digital model, an avatar, by which it is possible to execute prosthesis set up and evaluate its functionality simulating postures and movements. First, we describe the state of art of techniques used, i.e., virtual humans and motion capture systems. Then, the application of virtual humans for the prosthesis design and simulation is presented as well as preliminary results. © 2013 CAD Solutions, LLC.

Keywords: Prosthesis design | Virtual human | Virtual testing

[82] Bartesaghi S., Colombo G., Embedded CFD simulation for blood flow, Computer-Aided Design and Applications, 10(4), 685-699, (2013). Abstract
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Abstract: The aim of the study is the analysis of strategies and parameters to automate CFD simulations. The idea is to perform an Embedded CFD simulation for product development and verification. This work focuses on biomedical problems, in particular on vessel bifurcations with aneurysm located in the circulatory system. The research is conducted by the analysis of the pre-processing, solving and post-processing steps, in order to find a methodology that involves the reliable calculation of the CFD variables. For the pre-processing step, spatial grids study is conducted to find the element density that allows efficient calculations. The evaluations are done on a blood flow through an ideal artery bifurcation aneurysm. Subsequently the time step entity and the maximum inner iteration number are studied to calculate the independent variables. The time step is evaluated on the ideal bifurcation aneurysm with a constant inlet flow velocity, while the maximum inner iteration value is evaluated on the ideal bifurcation with a time dependent inlet flow velocity. The last study of the preprocessing is conducted on a reconstruction of real artery bifurcation aneurysm, modified with the extrusion of the inlet region, that allow the complete velocity field to develop. For each one, the original and the modified models, it's generated an unsteady simulation with set up in agreement with previous steps. A correct postprocess management study done through the pulsatile non-stationary simulation. The solution data will be used for the post-processing evaluations. So pressure and velocity evaluation layouts will be identified; Wall Shear Stress (WSS) based indices evaluation layouts will be implemented in order to enable a better evaluation of the case: Time Averaged Wall Shear Stress, Oscillatory Shear Index, Relative Residence Time. Lastly it will be considered a layout about Q-Criterion evaluation. The procedures defined during the study enable a partial automation of the CFD simulations. Acquiring an arterial bifurcation aneurysm model is possible to proceed to the automatic spatial grids generation; the numeric model is used to resolve unsteady flow, set with optimal parameters. Finally it is possible to evaluate the calculated variables by means of appropriate diagrams generation. © 2013 CAD Solutions, LLC.

Keywords: CFD | Hemodynamics | KBE

[83] Colombo G., Facoetti G., Rizzi C., Vitali A., Socket virtual design based on low cost hand tracking and haptic devices, Proceedings - VRCAI 2013: 12th ACM SIGGRAPH International Conference on Virtual-Reality Continuum and Its Applications in Industry, 63-69, (2013). Abstract
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Abstract: This paper concerns a research project that aims at developing an innovative platform to design lower limb prosthesis. The platform is centered on the virtual model of the amputee and is based on a computer-aided and knowledge-guided approach. In particular, the paper focuses on the module, named Socket Modeling Assistant-SMA, conceived to design the socket, the most critical component of the whole prosthesis. The underlining idea is to experiment low-cost devices, such the Leap Motion, to manipulate the 3D virtual model of the socket using hands as traditional done by the prosthetist. The goal is to make available a modeling tool that permits to replicate/emulate manual operations usually performed by the prosthetist during the traditional development process. First, we first describe the traditional socket development process; then the SMA software architecture and the guidelines used to develop the interaction algorithms (integrated within SMA) that exploit the Leap Motion and Falcon devices. Finally preliminary tests and results will be illustrated. © 2013 ACM.

Keywords: 3D modeling | hand tracking | haptic interaction | lower limb prosthesis

[84] Colombo G., Facoetti G., Regazzoni D., Rizzi C., A full virtual approach to design and test lower limb prosthesis, Virtual and Physical Prototyping, 8(2), 97-111, (2013). Abstract
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Abstract: Lower limb prostheses for above or below knee amputees are still designed and produced almost completely in a manual way, deeply relying on the experience and manual skills of orthopaedic technicians. This paper presents the main features characterising the prototype of a virtual environment developed to assist the technicians designing and testing the prosthesis. To reach the ambitious goal of replacing the manual process with a complete virtual one several issues have been considered and addressed: the capture and formalisation of process knowledge of orthopaedic technicians, the acquisition of patient's information and digital data, the development of an integrated solution to design and test standard and custom-fit components and the simulation of the gait of a virtual human wearing the virtual prosthesis. The architecture of the prosthesis design platform as well as the modelling and simulation tools are described. Finally, the experimentation phase and related results are presented and discussed. © 2013 Copyright Taylor and Francis Group, LLC.

Keywords: design environment | digital human modelling | lower limb | prosthesis

[85] Colombo G., Facoetti G., Gabbiadini S., Rizzi C., Socket modelling assistant for prosthesis design, International Journal of Computer Aided Engineering and Technology, 5(2-3), 216-241, (2013). Abstract
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Abstract: In this paper, we propose a knowledge-based approach to design lower limb prostheses; in particular, we focus on the 3D modelling of the socket, the most critical component. First, the architecture of a dedicated design framework is described, detailing features of the main design steps. Then, the paper discusses the acquisition and formalisation of the knowledge related both to the prosthesis manufacturing process and to the considered component. Finally, we present the computer-aided module, named socket modelling assistant-SMA, we specifically developed to design the socket. It is a virtual laboratory where the socket virtual prototype is generated directly on the digital model of patient's residual limb. It guides and supports the designer during each step in an automatic and/or semi-automatic way applying design rules and procedures. The modelling steps and available interactive tools that emulate orthopaedic technician's operations are described. Results of the experimentation phase are described. At current state of the prototype development, they are encouraging and have permitted to preliminarily validate the proposed approach and envisage future improvements. Copyright © 2013 Inderscience Enterprises Ltd.

Keywords: 3D socket modelling | Knowledge-based design | Lower limb prosthesis | Virtual prototyping

[86] Colombo G., Regazzoni D., Rizzi C., De Vecchi G., Motion capture and virtual humans to enhance ergonomic design and validation of refrigerated display units, Proceedings of the ASME Design Engineering Technical Conference, 2(PARTS A AND B), 663-671, (2012). Abstract
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Abstract: This paper presents a computer-Aided environment to analyze postures and movements in order to ergonomically validate the design of potentially any device a man or woman may have to deal with. The proposed environment integrates virtual prototyping techniques with Digital Human Modeling and Motion Capture techniques to determine fatigue, stress and risk for workersâTM health. We considered a vertical refrigerated display unit as case study to analyze the interaction of supermarket staff filling the shelves with goods with the main goal determining the suitability of operatorsâTM working condition and, eventually, providing a feedback to the design step. The paper, after a brief description of the state of the art of the Motion Capture system and Digital Human Modeling, presents the architecture of the integrated environment developed and the working paradigm. At last preliminary results of the experimentation as well benefits and the limits of the outcomes achieved so far in the automation of ergonomics in machines design are presented. Copyright © 2012 by ASME.

[87] Buzzi M., Colombo G., Facoetti G., Gabbiadini S., Rizzi C., 3D modelling and knowledge: Tools to automate prosthesis development process, International Journal on Interactive Design and Manufacturing, 6(1), 41-53, (2012). Abstract
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Abstract: Computer-aided tools can help to realize custom-fit products characterized by a strict interaction with human body and definitely improve quality of life, in particular of people with disabilities. The paper refers to this context and to a specific custom-fit product, the lower limb prosthesis. It presents an innovative framework centred on virtual models of the patient's body, to design and configure lower limb prosthesis, both transfemoral and transtibial. The framework integrates virtual prototyping and knowledge-based tools to support the orthopaedic technician during all the steps of the lower limb prosthesis design, suggesting rules and procedures for each task. First, the considered product is introduced, and then, the new design framework is described as well as main steps and related tools, from socket modelling to standards component selection and final prosthesis assembly. Results of preliminary experimentation and final remarks conclude the paper. © 2012 Springer-Verlag.

Keywords: Custom-fit products | Knowledge-based systems | Lower limb prosthesis | Socket | Virtual prototyping

[88] Colombo G., Facoetti G., Movigliatti D., Rizzi C., A virtual human for lower limb prosthesis set-up, ASME 2011 World Conference on Innovative Virtual Reality, WINVR 2011, 253-261, (2011). Abstract
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Abstract: This paper concerns the usage of virtual humans to validate lower limb prosthesis design. In particular, we are developing an innovative design framework centered on digital models of the whole patient or of his/her anatomical districts, which constitute the backbone of the design process. The framework integrates a set of virtual "assistants" to guide the technicians during each design task providing specific knowledge and design rules. In this paper, we focus the attention on the last step of the prosthesis deign process, i.e., the final set-up with the patient using a biomechanical model of the amputee. First, we describe the state of art on virtual humans and main features of the new design framework. Then, the application of virtual humans for the prosthesis set-up is presented as well as preliminary results. Copyright © 2011 by ASME.

Keywords: Lower limb prosthesis | Product development | Virtual humans | Virtual prototyping

[89] Colombo G., Gabbiadini S., Regazzoni D., Rizzi C., Design procedure and rules to configure lower limb prosthesis, Proceedings of the ASME Design Engineering Technical Conference, 2(PARTS A AND B), 673-681, (2011). Abstract
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Abstract: Modular lower limb prosthesis is composed by custom-fit parts, such as the socket containing the residual limb, and standard components available on market, such as knee or foot. For both custom and standard parts the support offered by existing design tools is not efficient or integrated enough and, as a result, most prosthetists do not use computer-aided tools and still rely only on their personal expertise. This paper presents an approach to design and configure complete lower limb prosthesis for transfemoral and transtibial amputees, using patient's digital data (e.g., residual limb model acquired by MRI) and specification sheets of components. The ultimate goal is to realise a virtual laboratory where the technicians can design lower limb prosthesis guided step by step by the system. We have identified key patient's characteristics guiding the prosthetist during the four main steps of the production process: acquiring patient's data, socket modelling, standard components selection and prosthesis assembly and check. The developed innovative framework integrates different tools to guide the technicians during each design task providing specific knowledge and rules. Thus, it allows a quicker and easier definition of the virtual prosthesis, on which virtual test could be performed (e.g., pressure distribution on residual limb, gait evaluation) in order to be able to realize the definitive prosthesis at the first attempt. The results have been evaluated and validated with the technical staff of a certified orthopaedic laboratory. © 2011 by ASME.

[90] Colombo G., Facoetti G., Morotti R., Rizzi C., Physically based modelling and simulation to innovate socket design, Computer-Aided Design and Applications, 8(4), 617-631, (2011). Abstract
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Abstract: This paper introduces a virtual laboratory to design prosthetic socket, which integrates a 3D CAD module, named Socket Modelling Assistant (SMA), specifically developed to create the socket digital model, and a CAE system to analyze the stumpsocket interaction. Software tool, named Virtual Socket Lab (VSL), is part of a knowledge-based framework to design lower limb prosthesis centered on digital models of the patient or of his/her anatomical districts. The focus of this paper is on the definition of an automatic simulation procedure to study the stump-socket interaction and validate socket design. We first introduce the new design framework and main features of VSL. Then, we present a state of art on FE models adopted for residual lower-limb and prosthetic socket during last two decades highlighting key issues. Finally, the identified procedure and the integration strategy within SMA are described as well as preliminary results of the experimentation. © 2011 CAD Solutions, LLC.

Keywords: Physics-based modelling and simulation | Socket | Socket-stump interaction

[91] Colombo G., Facoetti G., Gabbiadini S., Rizzi C., Virtual configuration of lower limb prosthesis, ASME International Mechanical Engineering Congress and Exposition, Proceedings (IMECE), 2, 681-690, (2010). Abstract
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Abstract: This paper presents a new design framework to configure lower limb prostheses, both transfemoral and transtibial, where the key elements are the patient digital avatar and the domain knowledge. The technician is supported during the design process by the knowledge acquired from analysis of the traditional process and represented in the framework. The last one integrates virtual prototyping tools and knowledge management techniques. A specific software tool, named Socket Modelling Assistant, has been developed to design the socket, the custom-fit component of the prosthesis. A commercial CAD system is used to model the standard components (e.g., knee, foot and tubes) and to create the final assembly. Patient avatar and his/her data (e.g., anthropometric and physiological parameters) are the backbone of the whole product design process. They guide both the selection of standard components and the modelling of the socket digital model. Copyright © 2010 by ASME.

[92] Colombo G., Facoetti G., Gabbiadini S., Rizzi C., 3D modelling of prosthesis socket with a knowledge based approach, Proceedings of the 8th International Symposium on Tools and Methods of Competitive Engineering, TMCE 2010, 1, 243-254, (2010). Abstract
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Abstract: In this paper, we propose a knowledge-based approach to design lower limb prostheses; in particular, we focus on the 3D modelling of the socket, the most critical component. First, the architecture of a dedicated knowledge based engineering framework is described, detailing features of the main design steps. Then, the paper discusses the acquisition and formalization of the knowledge related both to the prosthesis manufacturing process and to the considered component. Finally, we present a computer-aided module, named Socket Modelling Assistant-SMA, to design the socket; it is a virtual laboratory where the socket virtual prototype is generated directly on the digital model of patient's residual limb. It guides and supports the designer during each step in an automatic and/or semi-automatic way applying design rules and procedures. The guided modelling steps and available tools are described. Work in progress and future developments conclude the paper. © Organizing Committee of TMCE 2010 Symposium.

Keywords: 3d socket modelling | Knowledge-based design | Lower limb prosthesis | Virtual prototyping

[93] Facoetti G., Gabbiadini S., Colombo G., Rizzi C., Knowledge-based system for guided modeling of sockets for lower limb prostheses, Computer-Aided Design and Applications, 7(5), 723-737, (2010). Abstract
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Abstract: This paper presents a 3D CAD system to design sockets of lower limb prostheses, both transfemoral and transtibial. The proposed system, named Virtual Socket Laboratory, can be seen as a virtual laboratory where the user has at her/his disposal virtual tools that permit to emulate the procedures applied by orthopaedic technicians during the traditional socket manufacturing. The module is centred on the digital model of the patient and is based on the specific domain knowledge to guide the user during socket modelling suggesting the most appropriate design rules and procedures. First, main steps of the new design-modelling process and system functionalities are presented. Then, for each step, procedures carried during the traditional process, how they are executed with the new module and tools specifically developed are described. © 2010 CAD Solutions, LLC.

Keywords: 3d socket modelling | Artificial prosthesis design | Knowledge-based system

[94] Colombo G., de Ponti G., Rizzi C., Ergonomic design of refrigerated display units, Virtual and Physical Prototyping, 5(3), 139-152, (2010). Abstract
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Abstract: This paper presents a methodological approach to evaluate ergonomic issues of refrigerated display units. It is based on the use and integration of virtual human models with virtual prototyping techniques in order to support and optimize the product development process. The methodology has been investigated simulating the behaviour of two users' categories (customers and operators), which have different roles, needs, and ways of interaction with the machinery. Regarding customers, aspects related to reach capability and visibility were analyzed and quantified. For the operators, two typical tasks were analyzed (loading a unit and serving a customer), evaluating postures and movements respect to requirements established by international standards to reduce health risks. Ergonomic simulations were carried out varying unit type and configuration (number and types of shelves, etc.), manikin size and packed food (sizes and weight). © 2010 Taylor & Francis.

Keywords: Ergonomic analysis | Reaching | Refrigerated display units | Virtual human | Visibility

[95] Gabbiadirii S., Colombo G., Facoetti G., Rizzi C., Knowledge management and customised 3D modelling to improve prosthesis design, Proceedings of the ASME International Design Engineering Technical Conferences and Computers and Information in Engineering Conference 2009, DETC2009, 2(PART A), 625-633, (2010). Abstract
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Abstract: This paper presents a new approach to design lower limb prosthesis focusing the attention on geometrical model issues. The new design approach has been developed within national and international research projects and, at present, "ad hoc" tools to carry out specific tasks are under development. Within this context, an important role is played by product and process knowledge and by specific CAD tools to design the most critical component, the socket. The paper discusses acquisition and formalisation of the knowledge related to the prosthesis design, with particular attention to the socket, and presents main features of a CAD tool specifically intended for this highly customised component. Copyright © 2009 by ASME.

[96] Colombo G., Filippi S., Rizzi C., Rotini F., A new design paradigm for the development of custom-fit soft sockets for lower limb prostheses, Computers in Industry, 61(6), 513-523, (2010). Abstract
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Abstract: This paper presents a new 3D design paradigmfor the development of specific custom-fit products, such as the soft socket of prostheses for lower limb amputees. It is centered on the digitalmodel of the human body and, contrarily to the traditional process almost manually based, it considers the integration of methods and tools coming from different research and application fields: Reverse Engineering, Medical Imaging, Virtual Prototyping, Physics-based Simulation, and Rapid Prototyping. The paper describes the techniques adopted to acquire and create the digital model of the residual limb, the procedure to generate the socket model, the strategy developed for the functional simulation of the socket-stump interaction and, finally, the realization of the physical prototype. Each design step is described with the related problems and the obtained results. Both trans-tibial and trans-femoral amputees have been considered; however, for now the complete process has been validated for trans-tibial prostheses. Major outcomes of the proposed approach stand in a better quality of the final product, in a shorter involvement of the amputee implying a lower psychological impact, in a limited use of physical prototypes, and in a shorter development time. Moreover, the resulting paradigm answers to the Collaborative Engineering guidelines by optimizing the interaction between different domains and enhancing their contributions in a homogeneous development framework. © 2010 Elsevier B.V. All rights reserved.

Keywords: Custom-fit products | Human-centric soft product design | Physics-based modeling for soft products | Prosthesis development process

[97] Colombo G., De Angelis F., Luca F., Integration of virtual reality and haptics to carry out ergonomic tests on virtual control boards, International Journal of Product Development, 11(1-2), 47-61, (2010). Abstract
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Abstract: This work presents the results of a research project that evaluated the possibility to carry out ergonomic analyses on virtual prototypes that permitted tactile interaction. We propose an approach based on Virtual Reality (VR) and haptics: the former to improve visual rendering of a digital model, the latter to permit tactile interaction. The products considered were control boards. Atomic components such as knobs, sliders and buttons are employed. The paper presents the architecture of an ergonomic workstation and its first implementation based on commercial systems and ad hoc haptic devices specifically developed for the purpose. Major problems related to a VR environment, such as visualisation and human body tracking, are discussed; the architecture of haptic devices and technical solutions to achieve a satisfactory haptic rendering are presented. Finally, the paper proposes a test procedure and presents the results of tests on the behaviour of ergonomic workstation components. Work in progress and future developments conclude the paper. Copyright © 2010 Inderscience Enterprises Ltd.

Keywords: Control boards | Ergonomic tests | Haptic | Virtual prototype | Virtual reality

[98] Gabbiadini S., Colombo G., Facoetti G., Rizzi C., Knowledge management and customised 3D modelling to improve prosthesis design, Proceedings of the ASME Design Engineering Technical Conference, 2(PARTS A AND B), 625-633, (2009). Abstract
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Abstract: This paper presents a new approach to design lower limb prosthesis focusing the attention on geometrical model issues. The new design approach has been developed within national and international research projects and, at present, "ad hoc" tools to carry out specific tasks are under development. Within this context, an important role is played by product and process knowledge and by specific CAD tools to design the most critical component, the socket. The paper discusses acquisition and formalisation of the knowledge related to the prosthesis design, with particular attention to the socket, and presents main features of a CAD tool specifically intended for this highly customised component. © 2009 by ASME.

[99] Colombo G., Pugliese D., Rizzi C., Developing DA applications in SMEs industrial context, IFIP International Federation for Information Processing, 277, 69-82, (2008). Abstract
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Abstract: This paper discusses aspects related to the implementation of Design Automation applications within Small Medium Enterprises (SMEs) industrial context. It focuses the attention on some characteristics of the design process in SME context, and highlights issues of DA in relation to the characteristics previously evidenced. On this basis, it has been defined a methodology, named MEDEA (Methodology per Design Automation), to develop DA applications; it proposes a step by step roadmap and suggests methods and tools finalized to developers more skilled on products and design process than on IT technologies. Two industrial applications realized to evaluate the methodology are then presented. They are based on two different approaches: the first suitable to represent product structure and derived from Object Oriented programming and the second based on design process representation. © 2008 International Federation for Information Processing.

Keywords: Design automation | Knowledge representation | Knowledge-based engineering | PDM/PLM | SMEs

[100] Colombo G., Bronco D., Rizzi C., Regazzoni D., Virtual ergonomics analysis to validate product design, 5th International Industrial Simulation Conference 2007, ISC 2007, 311-315, (2007). Abstract
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Abstract: This paper presents an approach to evaluate product ergonomics using virtual humans. This work has been carried out to demonstrate that virtual humans are an important tool to improve virtual prototyping functionalities and, above all, to increase ergonomics and safety of products. A test methodology has been defined and several simulations have been made, varying anthropometry and workplace conditions. Two case studies that can demonstrate the validity of the approach are described. The first concerns instruments of a car for which the geometric model of the interior and a commercial virtual human have been used. The second case study concerns the external visibility of a farm tractor that can be equipped with different tools to accomplish to various tasks (e.g. harvesting and fruit picking). The results obtained are images that represent what the virtual human sees and permit to compare and validate different design solutions.

Keywords: Ergonomics | Internal and external visibility | Virtual manikin

[101] Pugliese D., Colombo G., Spurio M.S., About the integration between KBE and PLM, Advances in Life Cycle Engineering for Sustainable Manufacturing Businesses - Proceedings of the 14th CIRP Conference on Life Cycle Engineering, 131-136, (2007). Abstract
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Abstract: This article is focused on the integration between KBE (Knowledge Based Engineering) applications for Design Automation (DA) and companies' data repositories managed by PLM (Product Lifecycle Management), and PDM (Product Data Management) systems. In particular, the authors conducted their research proposing a method to retrieve data or documents of pre-existing components from a document repository, before proceeding to design products. As result of that, designers save time spent in design, verifying loops and documents producing, thanks to the reuse of existing components or product. In order to illustrate their approach, the authors developed an application where the KBE system checks the availability of existing components or products before let the designer proceed to design. New produced documents are stored into the data repository for next design activities. The paper is organized as following: first, it starts with the description of some relevant aspects in engineering design: product and process representation, knowledge reuse and sharing, PDM and KBE functionalities; then, the paper continues analyzing the functionalities of KBE and PDM system in order to introduce the issue of the integration; third, it goes on describing the approach followed by the authors; next, it describes the application above mentioned and performed by the authors on these topics; finally, the results of the work are reported.

Keywords: Design Automation | KBE | PLM

[102] Colombo G., Filippi S., Rissone P., Rizzi C., ICT methodologies to model and simulate parts of human body for prosthesis design, Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), 4561 LNCS, 559-568, (2007). Abstract
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Abstract: The work presented in this paper refers to the implementation of a product development process based on the use of virtual model of the human body to design specific custom-fit product, such as a prosthesis socket (interface between the residual limb and the mechanical part of the prosthesis). It considers the integration of advanced ICT tools coming from the reverse engineering, the physics-based modelling and simulation, and the rapid prototyping fields. The paper describes problems related to the implementation of each step within a real socket development process. © Springer-Verlag Berlin Heidelberg 2007.

Keywords: Human body modeling | Physics-based simulation | Product customization | Prosthesis design

[103] Colombo G., Bertetti M., Bonacini D., Magrassi G., Reverse engineering and rapid prototyping techniques to innovate prosthesis socket design, Proceedings of SPIE - The International Society for Optical Engineering, 6056, (2006). Abstract
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Abstract: The paper presents an innovative approach totally based on digital data to optimize lower limb socket prosthesis design. This approach is based on a stump's detailed geometric model and provides a substitute to plaster cast obtained through the traditional manual methodology with a physical model, realized with Rapid Prototyping technologies; this physical model will be used for the socket lamination. The paper discusses a methodology to reconstruct a 3D geometric model of the stump able to describe with high accuracy and detail the complete structure subdivided into bones, soft tissues, muscular masses and dermis. Some different technologies are used for stump acquisition: non contact laser technique for external geometry, CT and MRI imaging technologies for the internal structure, the first one dedicated to bones geometrical model, the last for soft tissues and muscles. We discuss problems related to 3D geometric reconstruction: the patient and stump positioning for the different acquisitions, markers' definition on the stump to identify landmarks, alignment's strategies for the different digital models, in order to define a protocol procedure with a requested accuracy for socket's realization. Some case-studies illustrate the methodology and the results obtained. © 2006 SPIE-IS&T.

Keywords: 3D geometrical model | Human body scanning | Lower limb prosthesis | Medical imaging | Rapid prototyping | Reverse engineering

[104] Colombo G., Pugliese D., The role of knowledge management in product lifecycle, Innovation in Life Cycle Engineering and Sustainable Development, 397-406, (2006). Abstract
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Abstract: The paper presents a discussion of some problems related to knowledge management in product lifecycle thought treating some applications developed in different aspects of lifecycle: conceptual design, detailed design, production, selling, maintenance, diagnostic and dismissing. In these applications, we show how Knowledge management is involved in all these phases: IT proposes several methodologies and tools to represent and manage knowledge to aid expert who operates in the domains related to product lifecycle. Methodologies such as Triz can be used to assist conceptual design, while KBE systems permit to automate design procedure of numerous products. Neural networks and fuzzy logic help to select right approaches to production. The paper ends presenting some applications performed by the authors, focusing aspects related to design. © 2006 Springer.

Keywords: Knowledge based engineering | Knowledge management | PLM

[105] Bordegoni M., Colombo G., Formentini L., Haptic technologies for the conceptual and validation phases of product design, Computers and Graphics (Pergamon), 30(3), 377-390, (2006). Abstract
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Abstract: The paper presents two applications of haptic technologies to demonstrate how they can increase human computer interaction during different steps of design process. The first application aims at developing a system to generate digital shapes by manipulating haptic tools that resemble the physical ones that the modelers use in everyday work. The second is focused on the use of haptic interfaces to evaluate ergonomics of virtual products control boards. We designed and developed the mentioned haptic devices; the first uses two FCS HapticMaster equipped with a innovative strong and stiff 6 DOF device carrying simulated clay modeling tools. The second is an "ad hoc" mechatronic device able to simulate some controls with rotary motions (knobs). The described haptic devices are integrated in more complex virtual reality applications; the paper describes their architecture and the methodologies proposed to simulate material shaping and ergonomic validation. The main aspects of haptic modeling and rendering are also discussed. © 2006 Elsevier Ltd. All rights reserved.

Keywords: Haptic modeling | Haptics | Product design | Virtual prototyping

[106] Colombo G., Girotti A., Rovida E., Automatic design of a press brake for sheet metal bending, Proceedings ICED 05, the 15th International Conference on Engineering Design, DS 35, (2005).
[107] Colombo G., Cugini U., Virtual humans and prototypes to evaluate ergonomics and safety, Journal of Engineering Design, 16(2), 195-203, (2005). Abstract
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Abstract: An important but neglected aspect of virtual prototyping is the interaction between human and digital prototype. This is an essential issue when tests about ergonomics or product safety are required. This paper presents an approach to evaluate product ergonomics and safety based on the use of virtual human and simulations where the human model interacts with the virtual prototype. Two case studies that can demonstrate the validity of the approach are described. The first concerns the instruments and external visibility of a car; geometric model of the interior and a commercial virtual human have been used. We defined a test methodology and several simulations have been made, varying anthropometry and workplace adjustments. The results obtained are images that represent what the virtual human sees and permit to evaluate the validity of design solutions. The second case study regards the ergonomics design of a riveting system and consists of the simulation of operator's tasks using a virtual workstation and a virtual human. The results are the joint angles that define the posture of the operator and permit one to analyse task comfort. This work has been carried out to demonstrate that virtual humans are an important tool to improve virtual prototyping functionalities and, above all, to increase ergonomics and safety of products. Moreover, the second case study demonstrates also that this methodology is today necessary not only in big industry, but in small-medium enterprises too. © 2005 Taylor & Francis Group Ltd.

Keywords: Ergonomics | Safety | Simulation | Virtual human | Virtual prototype

[108] Amabili M., Colombo G., Prati E., Experiments on the dynamics of a rubber ring seal, Shock and Vibration Digest, 32(1), 41, (2000). Abstract
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Abstract: The dynamic behavior of radial lip seals is investigated experimentally. The experimental apparatus consists of a fixed housing, a radial lip seal, and an internal disk simulating the shaft. The excitation is provided by a shaker connected with a stinger to the seal's lip, and the measurement is performed using an accelerometer placed on the internal disk. In some experiments, the internal disk is removed to test the seal without internal constraints and deformations. In this case, the accelerometer is placed on the seal's lip. Results show a softening-type nonlinear behavior of the system.

[109] Amabili M., Colombo G., Prati E., Experiments on the dynamics of a rubber ring seal, Proceedings of the International Modal Analysis Conference - IMAC, 1, 297-301, (1999). Abstract
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Abstract: The dynamic behaviour of radial lip seals is experimentally investigated. The experimental apparatus consists of a fixed housing, a radial lip seal and an internal disk simulating the shaft; the excitation is given by a shaker connected with a stinger to the seal's lip and the measurement is performed by using an accelerometer placed on the internal disk. In some experiments the internal disk is removed to test the seal without internal constraints and deformations; in this case, the accelerometer is placed on the seal's lip. The radial lip seal is excited along a fixed direction at different temperatures and without lubrication. The frequency response functions (FRFs) have been measured by using different excitation signals and different assembly interferences between the seal's lip and the shaft; the stiffening effect of the garter spring has also been investigated. Experimental results show a softening-type nonlinear behaviour of the system.

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