Abstract: This paper presents the design and preliminary evaluation of a mobile application developed to support home-based rehabilitation for patients recovering from cardiac surgery. The application uses the smartphone's built-in RGB camera in conjunction with MediaPipe's pose landmark detection to track body articulations and monitor exercise execution. A rule-based approach, driven by landmark positions, was implemented to evaluate user poses during the exercises. Based on this evaluation, the system tracks progression through a predefined sequence of states that represent correct execution. This method enables automatic repetition counting and the detection of common execution errors. Real-time visual and auditory feedback is provided, effectively simulating a virtual coach that guides patients through their rehabilitation routines. The application was tested with a specific rehabilitation exercise and demonstrated good reliability in both repetition counting and error detection. Although some limitations related to depth estimation by the smartphone camera were observed, the system shows promise as an accessible tool for guided rehabilitation, without the need for specialized equipment or clinical supervision, and has the potential to enhance patient engagement and adherence to rehabilitation protocols.

Keywords: Cardiac Rehabilitation | MediaPipe | Motion Capture | Pose Detection | Telemedicine

Abstract: Ontologies are gaining popularity in engineering applications as a conceptual tool for sharing information and knowledge between experts and software systems. However, most communities tend to focus on their own ontology, which is optimized for a limited set of tasks, resulting in models that are difficult to integrate with each other. This article explores how starting from a foundational ontology can enhance the quality of domain ontologies and improve their interoperability. To this end, we analyze the structure of Descriptive Ontology for Linguistic and Cognitive Engineering (DOLCE) OWL and investigate how it can be enriched for use in an engineering context. Our focus is on representing qualities and their values, particularly quantitative ones, which are crucial in engineering but often inadequately addressed by top-level ontologies. We propose various approaches for incorporating quantitative values, highlighting their pros and cons, and comparing them with other works present in the literature. The aim of the article is to enhance the usability of the foundational ontology DOLCE in practical engineering contexts, allowing engineers to concentrate on domain-specific aspects rather than the complexities of ontology usage.

Keywords: DOLCE | ontology | quality | unit of measure | value

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

Abstract: Prosthetic socket for lower limb amputation needs to be customized based on the residual limb characteristics to satisfy functional and comfort requirements. One of the main causes for ill-fitting socket is the lack of appropriate application of material properties that match the characteristics of the amputee's biological tissue. Additive manufacturing has the ability to confer inhomogeneous properties to the printed object. This paper presents a digital workflow for the design and fabrication of a prosthetic socket based on the results of numerical simulations and the use of multi-material voxel printing. A voxel model of the socket is generated and the contact pressure between the residual limb and the socket derived from FEA is mapped to the voxels, which were correspondingly assigned a material. This allow to define a material distribution at the voxel level and to generate printing instructions as a stack of bitmap images for voxel printing. The goal is to obtain a socket characterized by a spatial variation of material stiffness, according to the pressure map extracted from simulation, in order to adapt the socket to the patient's anatomy and, consequently, to reduce contact pressure and discomfort.

Keywords: 3D Printing | FEA | Heterogeneous Objects | Prosthetic Socket | Voxel Printing

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..