Human factors and ergonomics

Increasing product complexity makes usability matters more and more important to account for in product development processes. For this reason, tools to design and evaluate interaction are studied and developed day by day. Unfortunately, user non-determinism is difficult to manage. When problems occur during interaction, users can react in several, different ways, depending from their behavioral characteristics. The research described in this paper analyzes non-determinism in depth, characterize situations where it can raise and exploits an existing tool to model and manage it as best as possible. © 2014 Springer International Publishing Switzerland.

Keywords: Functional mock-up , Human-machine interaction , Simulation of non-determinism

Cultural heritage is often not accessible to visually impaired and blind people, hardly ever when dealing with two-dimensional artworks like, for instance, paintings. In fact, despite tactile reproductions of 3D works of art such as sculptures or architectural models are quite common, a real barrier between blind people and pictorial artworks still exists, obviously due to their intrinsic 2D format. The translation of paintings into bas-relieves is recognized to be one of the most effective ways for breaking down such a barrier, thus allowing a sensible improvement in blind people's accessibility to this kind of works of art. Moving from these considerations, in this work the authors want to provide a bird's eye view on a new methodology for the semi-automatic generation of tactile 3D models starting from paintings, in particular those characterized by single-point perspective. The proposed method relies on an interactive Computer-based modelling procedure, which is conceived to be simple and effective to use. The procedure, which has been implemented into a prototypal software package, has been effectively used to 'translate' a set of paintings from the Italian Renaissance.

Visually impaired and blind people are more excluded from equal access to the world's visual culture, thus being often unable to achieve concrete benefits of art education or to experience the life enhancing power of art. Despite the fact that all over the world several initiatives based on the interaction with sculptures and tactile three-dimensional reproductions or architectural aids on scale have been devised, a "sensory barrier" between blind people and pictorial artworks still exists, obviously due to their intrinsic 2D format. Translation of paintings into tactile models in the form of bas-reliefs is recognized to be one of the most effective ways for breaking down such a barrier, thus allowing a tangible improvement of the blind people's accessibility to artworks. In the recent years, computer aided technologies for automatic or semi-automatic translation of paintings into tactile models dramatically have been devised all over the world, thus improving blind people's accessibility to artworks. Inspired by some of these impressive works, this paper describes a user-driven methodology for the semi-automatic generation of tactile 3D models starting from paintings. Particularly devoted to the reconstruction of pictorial artworks characterized by single-point perspective, the proposed method relies on an interactive Computer-based modelling procedure. The method has been tested on two masterpieces of the Italian Renaissance period.

Keywords: 3d computer based modelling , Blind people , Haptic exploration , Single-point perspective , Tactile bas-relief

Over the last few years, technologies like 3D scanning and rapid prototyping provided an extraordinary boost in improving reproductions of 3D artworks, like sculptures and historical buildings, all over the world. Physical 3D reproduction of subjects represented in paintings, is recognised to be one of the best ways to allow visually impaired people to enjoy such kind of artworks. However, the use of advanced technologies with the aim of realising 3D models starting from paintings has not been satisfactorily investigated yet. Though a number of algorithms coming from computer vision science exist to cope with similar issues, the specific problem of producing a 3D representation which is targeted at blind people tactile exploration has been only marginally investigated. Starting from these considerations, this work presents 1) a quite extensive review of the criteria proposed in literature for producing tactile models suitable for blind people and 2) four alternative computer-based methods for semi-automatic generation of tactile 3D models starting from RGB digital images of paintings. The outcomes of this study contribute new information to the field of visually impaired user-oriented 3D reconstruction and clearly indicate the strategy to be adopted in order to produce a meaningful reproduction of a bi-dimensional piece of artwork. © 2014 Inderscience Enterprises Ltd.

Keywords: 3D computer-based modelling , Blind , Haptic exploration , Visually impaired

Multimodal sensory stimulation is one of the most important challenges in human-computer interaction. When we want to play a virtual system it is important that the reproduced signals to stimulate the different sensory channels are synchronized with each other. This paper presents the study and implementation of a multimodal stimulation system. The proposed system is a step forwards a previous developed tactile platform (called Ipertouch 1.0). Main novelties regard the introduction of audio and visual feedbacks and signals synchronization. For acoustic stimulation, an auralization algorithm is applied on records of rubbing finger on a given class of material. For visual stimulation, a 3D rendering software is developed. Tests are performed to evaluate the degree of synchronism among the three different sensory channels.

Keywords: acoustic and visual feedback , haptic , multimodal system , synchronism

Numerous smart home systems have been created in the recent years, but they still lack of high interoperability and research has been focused on single smart technologies instead of the system interoperability as a whole. Furthermore, available systems are usually strongly technology-oriented and they neglect the user's satisfaction and the benefits' analysis. In addition to this, modern systems impose the intelligent management of a huger amount of data, which needs to be properly coordinated to achieve higher performances and offer new energy-control services. This paper defines an information management model to improve device interoperability in smart homes. It allows selecting and classifying the devices, visualizing their data model, aggregating the necessary data according to the desired service functions, and finally defining a set of rules to coordinate device operations according to user preferences and external events. A case study focused on washing machines is presented to demonstrate the methodology implementation; it allows designing and developing an energy-control service for the selected device and optimizing its functions according to the users' needs and preferences as well as the constraints of the use scenario. Finally, the benefits achieved with such a new service are evaluated in terms of energy consumption, costs reduction and user satisfaction in a simulated home environment that represents practical scenarios of use.

Keywords: Customized and personalized product development , Intelligent design , Smart product engineering

Haptic simulation of materials is one of the most important challenges in human-computer interaction. A fundamental step to achieve it regards the definition of how human beings can encode the information acquired by different sensorial channels' stimulation. In this context, this paper presents the study, implementation and evaluation of a multi-modal cutaneous feedback device (CFD) for the simulation of material textures. In addition to tactile stimulation, two further sensory components (e.g. eyesight and hearing) are integrated to support the user to better recognize and discriminate different classes of materials and then, overcome previous identified drawbacks. An experimental protocol is tuned to assess the relevance of each stimulated channel in material texture recognition. Tests are carried out with real and virtual materials. Result comparison is used to validate the proposed approach and verify the realism of simulation. © 2014 Springer International Publishing.

Keywords: Elettrocutaneous feedback , haptic , multi-modal stimulation

In the last years, some attempts have been made to explore the use of smart objects, with the purpose of monitoring well-being and supporting people's independent living. However an inventory of characteristics of smart products currently available on the market is still lacking. The aim of this study is to provide an overview of such products in order to: (1) understand if their features really match users' needs, answering to the definition of assistive technology and, consequently, (2) understand if an environment embedded with SOs can be considered as assistive too, taking into consideration the attributes given by the definition of the SOs, of being embedded in familiar objects and immerse in the users' surround. © 2014 Springer International Publishing Switzerland.

Keywords: Home Environment , Inclusive Design , Internet of Things , Universal Design

Quality of life of various types of people can strongly benefit of a design process developed to take into account needs and requirements of end users. In this context the paper present a study on the cognitive and physical abilities of elderly persons, to design a friendly kitchen, that is considered one of the most complex home environment for the provided functionalities and involved human capabilities. A robust inclusive design approach is conceived to make simple and intuitive the interaction between humans and the systems installed in the kitchen environment. An investigation of virtual prototyping techniques is proposed to find the best Virtual Reality system to create a living lab to involve elderly in user-based assessment.

Keywords: home environment , mixed reality , user-centred-design , virtual prototyping

The ISO 9001: 2000 requires the phase of design validation in order to demonstrate that the design output are able to satisfy specified or forecasted user requirements; for this reason, generally, physical prototype are realized in order to evaluate real product performances and their correlation with simulated ones. In this paper, the use of virtual inspection probes to validate playground equipment design is studied, pointing out limits and defining the optimal test strategies. Through the use of Robust Design techniques the authors show that the combined use of real time shadows and positional sound feedback allows to reduce the percentage of wrong inspections in the validation phase of playground equipment design. The authors develop an inspection probe simulation tool in virtual immersive environment. In particular, this tool ensures the collision detection through visual and sound feedback and increases the realism of the immersive environment. Finally, an experimental session, using a physical prototype of playground equipment, is carried out in order to compare these results with the ones coming out from the VR experiments. For a standard entrapment test, the authors assess the dependences of false and missed alarm by the diameter of the openings to evaluate and establish an acceptability threshold for the usability of the virtual probes. © 2013 Springer-Verlag France.

Keywords: Design validation , Grasping techniques , Playground equipment , Usability , Virtual reality

The aim of the paper is to address an innovative methodology for assessing the usability of a product. This methodology is particularly suitable for designing products that provide their main functions through their control interfaces. In particular, this case study relates to the usability assessment of two control devices for a wheelchair-mounted robot manipulator to assist physically disabled people. The study focuses on defining a synthetic usability index on the basis of two currently used methods: the multi criteria decision analysis and the Saaty's analytic hierarchy process. Several virtual reality (VR)-based experiments have been conducted, set up in accordance with a cross-array experimental plan, that adequately caters for both control and noise factors. Quantitative measures and subjective user evaluations have been collected to maximize the effectiveness, the efficiency and the satisfaction perceived by users while using the product. Compared to the literature on the subject, the proposed approach provides both more flexibility in defining quantitative indexes and more adequate results, even when involving only a small sample of users in the participatory design session. The use of VR technologies for the collection of the experimental data has been essential in terms of safety, costs and repeatability of the tests, as well as of the robustness with respect to noise factors. © 2012 Springer-Verlag London Limited.

Keywords: Analytic hierarchy process (AHP) , Assistive robotics , Participatory design , Usability index , Virtual reality experiments

Trailers are used to carry logs having specific dimensions for logging extraction operations, secondary transportation, and agricultural activities. The main objective of this study was the design of a timber trailer capable of manual loading operations and suitable for rough terrain conditions to be used in combination with a farm tractor in the western Black Sea region of Turkey. In the proposed methodology, a House of Quality diagram was used to transfer customer requirements into quality characteristics, and focus the development of the product toward customer satisfaction. Negative correlations between quality characteristics were solved using the TRIZ contradiction toolkit and generating different concepts. Inventive solutions provided by TRIZ were designed with parametric CAD software. Several concepts were compared in a participative design review session in an immersive virtual reality environment. To choose an optimal concept, the analytic hierarchy process (AHP) was used. The final concept has a total length of 3.35 m, width of 1.34 m, and height of 1.8 m. The mass is 2700 kg, the payload capacity is about 2.33 m3, and the total volume of the chassis is 2.68 m3 The angle of rollover is 26.9°, the door is reachable by 90% of the population, and the lower back analysis performed for the loading operation showed a maximum value of 2597 N. The final concept is capable of movement in steep terrain and with the presence of obstacles, carrying logs up to 3-m long. It is more productive among high-density stand trees, allows for ergonomic loading operations, and reduces environmental damage to soil and vegetation. © TÜBİTAK.

Keywords: AHP , Ergonomics , Forest harvesting , Interactive design , QFD , TRIZ

It was reported that next to style, comfort is the second key aspect in purchasing footwear. One of the most important components of footwear is the shoe sole, whose design is based on many factors such as foot shape/size, perceived comfort and materials. The present paper focuses on the parametric analysis of a shoe sole to improve the perceived comfort. The sensitivity of geometric and material design factors on comfort degree was investigated by combining real experimental tests and CAD-FEM simulations. The correlation between perceived comfort and physical responses, such as plantar pressures, was estimated by conducting real tests. Four different conditions were analyzed: subjects wearing three commercially available shoes and in a barefoot condition. For each condition, subjects expressed their perceived comfort score. By adopting plantar sensors, the plantar pressures were also monitored. Once given such a correlation, a parametric FEM model of the footwear was developed. In order to better simulate contact at the plantar surface, a detailed FEM model of the foot was also generated from CT scan images. Lastly, a fractional factorial design array was applied to study the sensitivity of different sets of design factors on comfort degree. The findings of this research showed that the sole thickness and its material highly influence perceived comfort. In particular, softer materials and thicker soles contribute to increasing the degree of comfort. © 2012 IPEM.

Keywords: CAD-FEM modeling , Comfort assessment , Fractional factorial design , Numerical-physical correlation , Pressure map , Shoe sole

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

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

Maintenance is one of the key drivers for future company success, due to the fact that these kinds of operations are strictly related to human labor cost, an expensive factor for western states. Furthermore, in the last decades, norms and laws on safety and ergonomics of the work place have taken importance among industrialized countries. Design for Maintenance is a design methodology that since early stages of product life cycle outlines needs and necessities of maintainers, in order to reduces time and cost; decreasing the complexity and the difficulties of these procedures and achieving a higher standard of workers' health. In order to reach this goal, Digital Human Models (DHM) have been used to simulate assembly and maintenance processes. Virtual ergonomic analysis performed with a human model allows evaluating visibility, reachability and postures, stress and fatigue. The lack of methods supporting virtual ergonomics simulation has been addressed by proposing a systematic approach based on a step-by-step procedure and proper tools. The said procedure was applied on a case study and results on the method and on its application are shown. © 2013 Copyright CAD Solutions, LLC.

Keywords: design for maintenance , digital human modeling , ergonomics

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

A multi-factor authentication framework relays on the usage of two or more sources of data for identity retrieval. Moving from authors' previous experimentation on two factor biometric authentication frameworks, the present paper shows the impact of the usage of neural networks as a way to fuse the outcomes of the different factors. The aim is to experiment neural networks as a way to map the multidimensional probabilistic space of a multi-factor biometric framework into the mono-dimensional binary space required by an authentication system.

Keywords: Authentication , Neural networks , Signature , Voice