Abstract: The wind has been a natural and renewable resource used for professional and recreational maritime transportation of small and large vessels since human history. Sailing is making a comeback due to the growing focus on sustainability, accelerated by the recent global energy crisis. Seafarers rely on wind and bearing angle visualization to navigate efficiently and safely, thanks to the use of sensors and compasses. This paper focuses on Augmented Reality in Head-Mounted Displays visualization of wind and bearing angle data. We analyzed the literature and generated a heatmap of the used areas in the user’s field of view. Second, we designed and implemented two interfaces that use two different visualization techniques: Boat Stabilized (BS) and Head Stabilized (HS). We compared them in between the subject experiment (N = 44), using a simulated Virtual Reality simulator of the sailing scenario. The user’s primary task is wind events recognition, while obstacles (buoys) detection is secondary. We measured both task errors and reaction time, and submit NASA RTLX, SUS, UEQ, and visive auditive and kinesthetic (VAK) questionnaires. We found that BS has a significantly lower reaction time and better usability in the primary and secondary tasks. Both visualization techniques have similar users perceived cognitive load and user experience evaluation. VAK test showed that BS is better for kinaesthetic types and HS is better for visual types.

Keywords: Augmented reality | Human–computer interaction | Nautical | Navigation | Sailing | User study

Abstract: In this work, a procedure for modelling and simulating conformal biomimetic scaffolds for bone tissue engineering is presented. Starting from a three-dimensional biomedical model of a real human mandible presenting a severe damage, a conformal shape was modelled and filled with an irregular beam network mimicking human trabecular bone. The material considered for the realization of the scaffold was hydroxyapatite derived from fish industry by-products, a material that is highly biocompatible to human bone. Several simulations were conducted on a beam-based wireframe model by varying the radius of the trabeculae, until reaching a stiffness of the scaffold equal to that of human bone. This represents a good design practice to avoid the stress shielding effect on growing bone tissue and functionality losses during bone regeneration. The resulting porosity and the average pore size, which are fundamental properties to ensure a proper vascularization of the growing tissue, were measured and compared to literature data, showing an acceptable agreement. The proposed beam-based approach for modelling and simulating conformal irregular scaffolds appeared as an interactive, fast, and versatile procedure that can be applied in the design stage of conformal biomimetic scaffolds for bone tissue regeneration.

Keywords: Bone Tissue Engineering | CAD Modelling | Mechanical Simulation

Abstract: [No abstract available]

Abstract: In the era of Industry 4.0, designers are expected to use new tools and approaches to innovate the design of products and services. From this perspective, the integration of design practices and technologies of the 4.0 transition can have positive implications for sustainability. Several current issues can be addressed and among them, honeybee death is relevant. Honeybees are fundamental to the ecosystem and human life. Nevertheless, their lives are extremely at risk due to exposure to several disease factors. After conducting expert interviews, the paper presents a conceptual model of intelligent beekeeping to monitor the health status of honeybees. Furthermore, after user research, the paper proposes a co-design model for urban beekeeping, scaled up to a condominium dimension, to allow condominiums and expert beekeepers to be part of an integrated design model. The critical proposition of this model is to raise awareness of the problem of honeybee death to achieve 3 out of 17 United Nations’ Sustainable Development Goals: Good Health and Well-Being, Sustainable Cities and Community, and Life on Land. Early results report positive values of acceptance of the urban beekeeping practice by users and the use of IoT in managing beehives and their health status by expert beekeepers.

Keywords: Co-design | Design for sustainability | Industrial design | Industry 4.0 | IoT technology | Urban beekeeping

Abstract: Chromotherapy rooms (CRs) are physical spaces with colored lights able to enhance an individual’s mood, well-being, and, in the long term, their health. Virtual reality technology can be used to implement CR (VRCRs) and provide higher flexibility at lower costs. However, existing VRCRs are limited to a few use cases, and they do not fully explore the potential and pitfalls of the technology. This work contributes by comparing three VRCR designs: empty, static, and dynamic. Empty is just a void but a blue-colored environment. Static adds static abstract graphics (flowers and sea texture), and dynamic adds dynamic elements (animated star particle systems, fractals, and ocean flow). All conditions include relaxing low-beta and ocean sounds. We conducted a between-subject experiment (n = 30) with the three conditions. Subjects compiled a self-perceived questionnaire and a mathematical stress test before and after the VRCR experience. The results demonstrated that the dynamic condition provided a higher sense of presence, while the self-perceived stress level was insignificant. Dynamic VR conditions are perceived as having a shorter duration, and participants declared that they felt more involved and engaged than in the other conditions. Overall, the study demonstrated that VRCRs have a non-trivial behavior and need further study of their design, especially considering their role in a future where VR will be an everyday working interface.

Keywords: color therapy | immersive virtual worlds | interaction design | stress management | user presence | wellbeing

Abstract: The metaverse, driven by mixed reality (MR), is positioned as the future market, revolutionizing product exploration in virtual space. Existing literature on this subject mainly focuses on Business-To-Consumer (B2C) perspectives, leaving a gap in understanding Business-To-Business (B2B) applications, particularly in the fashion industry. This paper introduces a “Mixed Tactile Catalog” (MTC) for B2B that combines a physical, foldable cardboard booth with an MR application linked to a Head-Mounted Display (HMD). Targeting the fashion sector's need for high standards in material evaluation, the MTC allows retailers and distributors to browse garments, customize material attributes, and receive visual and tangible feedback. Evaluation through a focus group of 10 industry experts revealed positive feedback. The MTC maintains the tangibility of traditional B2B showrooms and reduces the environmental impact by minimizing transportation, samples, and waste. This innovative approach offers an efficient and sustainable alternative to conventional physical showrooms, enhancing both economic and ecological aspects.

Keywords: Clothing | Extended reality | Haptic interfaces | Industries | Metaverse | Virtual reality | Visualization

Abstract: Virtual reality metaverse is candidate to be the future platform for re-tail. Nevertheless, the knowledge in designing virtual environments and their influence on products is limited in literature. Common 'brick and mortar' virtualization of shops as realistic digital twin is a reductive approach compared to more creative experiences. This work explores novel paradigms by evaluating 'anomalous environ-ments' deviated from the ordinary conception. Different anomalies are evaluated within 8 scenes promoting an existing line of futuristic-looking tracksuits. The experimentation on 42 subjects, shows that anomalous environments, especially when aligned with the product's storytelling, can increase products likeability, interest and perceived valorization.

Keywords: fashion | Metaverse | perception | product valorization | retail | storytelling | virtual environments | virtual reality

Abstract: Conveying the quality of garments through media as in the physical store is demanding. This study proposes the design of a VR interface that aims to convey outerwear quality, featuring the 3D model animated through physical simulation. To measure the effectiveness of this interface, it is tested simultaneously with its corresponding desktop counterpart, with the photo gallery of the product, in a within-subject analysis on 50 users. Results show that perceived quality of products changes between the experiences. Moreover, in VR visual content was found to be more significant for the quality assessment than written information.

Keywords: outer-wear | perception | quality | user interface | Virtual reality

Abstract: One key aspect of the fashion industry is the presence of small manufacturing companies and their need to present a sample collection to the reseller and find wholesalers. This Business-to-Business (B2B) activity is characterized by complex storytelling and communication methods to convey the value of the products: materials, finishes, sizes, and fit options. Usually, the showroom is used to present the garment collection, a representative of the manufacturer, and one or more resellers. Setting up a physical showroom is expensive and requires the transportation of the entire collection. During the pandemic, when physical interactions were severely limited, companies had to adopt alternative solutions by using the Internet to communicate with other companies. By the end of this period, the use of such solutions proved to be extremely convenient and practical. We present a Metaverse-based showroom, that differently from the literature focuses on B2B fashion showrooms instead of direct sales or retail. We based on the VRChat and used Head-Mounted Displays (HMD) to recreate a real-life showroom. The users are remotely seated at a shared desk in front of the catwalk. The reseller can interact with the following functions: collection presentation, fashion show participation, and material/color configuration. We conducted a user study with 10 expert subjects, simulating two remote-selling scenarios of a jacket collection from a partner company with real experienced sellers and distributors user and assessing the user experience measurement. The user test is measured with the User Experience Questionnaire (UEQ). The results showed positive evaluations in terms of attractivity, apprendibility, stimulation, originality, and positive outcomes regarding sustainability.

Keywords: Business-To-Business | Fashion Industry | Metaverse | Showroom | User Experience | Virtual Reality

Abstract: In recent years, many industrial companies have embraced new technologies for Industry 4.0, the fourth industrial revolution. This global manufacturing trend connects real-life industry with the virtual world. Digitalization tools play a crucial role in allowing companies to decrease design and production costs, as well as accelerate the product development process. Regarding an actual industrial case study of an Italian automotive company, this work focuses on the use of digital technologies in designing complex manufacturing systems, showing the benefits that can be obtained with respect to traditional methods. Digitalization tools have aided in the design of intricate manufacturing systems that demand advanced automation to optimize the arrangement, workflow, and equipment configuration within a manufacturing facility or production line. After examining the features of the virtual approach employed by the considered company, the virtual commissioning of a screwing station for an electric axle assembly line is analyzed in detail to show the efficiency and effectiveness of digitalization.

Keywords: Automotive | Complex Manufacturing Systems | Digital Technologies | Industry 4.0 | Virtual Commissioning

Abstract: Dental tool positioning is a challenging manual operation that requires precise 5DOF positioning of the drill -rotation around the tool is not influential- minimal error can result in grave consequences such as nerve and bone damage. Augmented Reality (AR) can help to assist tool positioning, but the widgets proposed in the literature are quasi-static, commonly using virtual 3D cylinders or lines to be visually collimated and eventually supported by color change. We draw our inspiration from the photographic viewfinder and propose a novel Virtual Stigmometer Widget (ViSti) to convey tool positioning error magnitude to the dentist. The widget slightly blurs the view and gradually focuses it while approaching the target (i.e., implant drilling position) till it is perfectly collimated. We conducted a within subjects experiment (N = 30) to compare our widget with the golden standard in 32 positioning tasks. NASA-TLX results demonstrated that our widget reduces frustration (−43%), and mental demand (−19%), and the user perceives a better performance (+8%). However, the expected tradeoff is effort (+34%), and physical (+33%) temporal demand (+4%). Our widget demonstrated to have a potential usage for dentistry and in further fields where 5DOF precision is crucial.

Keywords: 5DOF manipulation | Augmented Reality | Dental Implantology | Human Centered Design | Stigmometer

Abstract: In recent years, Augmented Reality (AR) has been effectively proposed as a tool to support workers in manual procedural tasks in industry, such as assembly and maintenance. It is very common for workers to deal with complete equipment in maintenance. Then, instructions may refer to components located in blind areas, i.e., visually occluded by part of the equipment. Displaying in-situ AR instructions in such blind areas requires handling occlusions; otherwise, side-by-side instructions can be exploited. In the literature, it is still unclear which solution better leverage workers’ performance in maintenance tasks accomplished in blind areas. Thus, we designed three AR presentation modes to convey maintenance instructions in a real machine: 3D in-situ rendered with X-ray technique; 3D side-by-side on a CAD model replicating the blind area; 2D side-by-side on a virtual mirror. We conducted a user study comparing these three presentation modes with a 2D drawing extracted from the original maintenance documentation of the machine. The performance of 42 participants was evaluated in terms of completion time, accuracy, and cognitive load. The results revealed that both in-situ and 3D side-by-side presentation modes perform better than 2D drawing. Specifically, the in-situ presentation mode outperforms the 3D side-by-side mode in terms of completion time. The side-by-side virtual mirror does not improve performance with respect to 2D drawing, then it needs to be redesigned for effective use in AR maintenance interfaces.

Keywords: Augmented reality | Blind area | Industrial operator support | Maintenance | Occlusion | Work instructions

Abstract: For the sake of being competitive in an ever-changing market, industrial companies need a redefinition of traditional design and integration of parts, equipment, and services such a redefinition allows effectively addressing the interaction between machines and operators, particularly in the area of complex production lines. In this context, enhancing ergonomics is crucial to reduce fatigue and stress of workers and increase work-place efficiency and comfort. Moreover, identifying ergonomic flaws in three-dimensional human-machine design problems (e.g., body posture, reach, visibility) at an early stage of the engineering process allows to prevent these issues at a low cost. Virtual reality (VR) is emerging as a powerful tool to improve the ergonomic assessment in the design of complex production lines. However, VR is not yet a well-consolidated practice for industrial companies, and the state-of-the-art applications are limited to simplified, isolated, and customized experiments. This work proposes the use of a virtual golden zone (VGZ) as a standard and efficient VR method for the ergonomic analysis and optimization of operator activities in manual manufacturing stations. The resulting effectiveness and benefits are highlighted through the application of the approach to a real industrial case study. Finally, the outcomes of a usability questionnaire, compiled by the professionals involved in the VR reviews, are presented to evaluate the usability of the VGZ methodology in the design process of complex production lines.

Keywords: Complex production lines | Ergonomics | Human computer interaction | Virtual reality

Abstract: This work is part of a larger project aiming to develop a comprehensive Augmented Reality (AR) interface for recreative and professional nautical sailing navigation. Due to the complexity of the marine environment and the dynamism of the crew members on board, we propose to diversify the display of navigation information concerning the role, position and activity onboard. The interfaces are designed to be viewed by one or more crew members, solving the problem of everyone viewing the same data, and giving each one the information they need based on their role or position. The three novel proposals for sail-specific AR graphic interfaces are designed to be displayed on Head-Mounted Display HMD and each of them differs for the information stabilization: Screen-Stabilized, Body-Stabilized and Boat-Stabilized. Each interface is different from the others differentiated according to the type of navigation and the user who must use that information. These approaches have been prototyped and evaluated by a panel of experts in the field of sailing navigation and were able to showcase their potential for future evaluations in different scenarios.

Keywords: Augmented Reality | Interface | Nautical | Sailing | Spatiality | User-based

Abstract: In the ever-changing scenario of technology evolution, designers need to develop new interactive systems that respond to users’ needs. Augmented Reality (AR) could be a tool and an opportunity for designers to create novel interactive systems. AR has proven to be effective in several domains, showing potential for widespread deployment even in everyday life tasks such as the use of household appliances. Thus, leveraging the Human-Centred Design (HCD) approach, we integrate AR into the design and development process of an interactive system for household appliances. Based on our survey results with 463 participants, one of the appliances that could benefit most from AR is the kitchen machine. Starting from a case study, we develop a demo to prove the feasibility of designing interactive systems with the integration of AR technologies, following the HCD approach.

Keywords: Augmented Reality | Human-Centred Design | Industrial Design | Interactive System | User Interface

Abstract: The design research and education landscapes are changing. The widespread development and use of technologies such as Mixed Reality (MR) and the diffusion of Head-Mounted Displays (HMDs) available at low cost are causing a shift in design education toward the Metaverse. In this ever-changing scenario, there is a need to rethink design and teaching methods. However, scientific literature lacks the ability to provide contributions that include MR technology education in the industrial design program. We, therefore, present an innovative laboratory with an integrated multidisciplinary approach that starts from the fundamentals of interaction design and aims to teach students how to design next-generation MR interfaces for the Metaverse. The lab combines theory and practice within three courses: Information Design, Information Systems, and Virtual Design and Simulation. Industrial design students follow a precise multidisciplinary method consisting of five steps, from state-of-the-art analysis to the presentation of a final group design of an MR user interface. Thus, we introduce a class case study by presenting the outcomes of a semester project in the field of household appliances. Evaluation of the teaching method is conducted through a semi-structured questionnaire. Preliminary results show positive outcomes from students in terms of acceptance, effectiveness, usefulness, efficiency, and satisfaction with the teaching method adopted for the laboratory.

Keywords: industrial design | interaction design | metaverse | mixed reality | teaching method | user interface design

Abstract: With the high growth and prosperity of e-commerce, the retail industry needs to explore new technologies that improve digital shopping experiences. In the current technological scenario, Virtual Reality (VR) emerges as a tool and an opportunity for enhancing shopping activities, especially for the fashion industry. This study explores whether using Immersive Virtual Reality (IVR) technologies enhances the shopping experience in the fashion industry compared to Desktop Virtual Reality (DVR). A within-subject experiment was carried out involving a sample of 60 participants who completed a simulated shopping experience. In the first mode (DVR), a desktop computer setup was used to test the shopping experience using a mouse and keyboard for navigation. The second mode (IVR) exploited a Head-Mounted Display (HMD), and controllers, that allowed navigation while seated on a workstation to avoid sickness. Participants had to find a bag in the virtual shop and explore its features until they were ready to purchase it. Post-hoc measures of time duration of the shopping experience, hedonic and utilitarian values, user experience, and cognitive load were compared. Results showed that participants experienced higher hedonism and utilitarianism in the IVR shop compared to DVR. The cognitive load was comparable in both modes, while user experience was higher in IVR. In addition, the time duration of the shopping experience was higher in IVR, where users stayed immersed and enjoyed it for longer. This study has implications for fashion industry research, as the use of IVR can potentially lead to novel shopping patterns by enhancing the shopping experience.

Keywords: Fashion industry | Retailing | Shopping experience | User study | Virtual reality

Abstract: On October 21, 2022, the 21st IEEE International Symposium on Mixed and Augmented Reality (ISMAR 2022) was successfully completed in Singapore. ISMAR is the leading international conference in the fields of augmented reality, mixed reality, and virtual reality. This was the first time that ISMAR was held in Southeast Asia and the first time in hybrid mode. ISMAR 2022 achieved a historically high number of papers and attendees, witnessing the steady growth of the community and the scientific contributions. In this article, we report the key outcomes, impressions, research trends, and lessons learned from the conference.

Keywords: Augmented reality

Abstract: This paper provides a critical overview of Design for Sustainability (DfS) and Design for Well-Being practices as, today, sustainability, human behavior, and well-being are inextricably linked. We present a case study in response to a pharmaceutical company brief about cosmetic self-production packaging. Since the research takes place during the first lockdown due to Covid-19, it depicts quite a complex and extensive desk phase and a limited field phase. The research is approached on two levels. First, is the intention to change the way we interact with the packaging. As a container of elements, packaging can be a resource on all levels, not only because we can recycle it but also because we can replant it. In this way, we would return part of what had been taken away to the environment while also improving the product’s life cycle. Thus, packaging becomes “behavioral”, producing and stimulating conscious behavior and motivating end-users while also educating them about environmental norms. Second, the Critical Design method traces the connections between DfS and Design for Well-being by leveraging the two practices within product design, clarifying the role of the designer in this transdisciplinary integration.

Keywords: Behavioral Packaging | Design for Sustainability | Design for Well-being | DIY | Industrial Design | Product Design

Abstract: In this special issue of IEEE Transactions on Visualization and Computer Graphics (TVCG), we are pleased to present the journal papers from the 22nd IEEE International Symposium on Mixed and Augmented Reality (ISMAR 2023), which will be held as a hybrid conference between October 16 and 20, 2023 in Sydney, Australia. ISMAR continues the over twenty-year long tradition of IWAR, ISMR, and ISAR, and is the premier conference for Mixed and Augmented Reality in the world.

Abstract: The creation and management of content are among the main open issues for the spread of Augmented Reality. In Augmented Reality interfaces for procedural tasks, a key authoring strategy is chunking instructions and using optimized visual cues, i.e., tailored to the specific information to convey. Nevertheless, research works rarely present rationales behind their choice. This work aims to provide design guidelines for the localization of in-view and not occluded components, which is recurrent information in technical documentation. Previous studies revealed that the most suited visual cues to convey this information are auxiliary models, i.e., abstract shapes that highlight the space region where the component is located. Among them, 3D arrows are widely used, but they may produce ambiguity of information. Furthermore, from the literature, it is unclear how to design auxiliary model shapes and if they are affected by the component shapes. To fill this gap, we conducted two user studies. In the first study, we collected the preference of 45 users regarding the shape, color, and animation of auxiliary models for the localization of various component shapes. According to the results of this study, we defined guidelines for designing optimized auxiliary models based on the component shapes. In the second user study, we validated these guidelines by evaluating the performance (localization time and recognition accuracy) and user experience of 24 users. The results of this study allowed us to confirm that designing auxiliary models following our guidelines leads to a higher recognition accuracy and user experience than using 3D arrows.

Keywords: Augmented reality | Authoring | Auxiliary model | Localization

Abstract: In this work, we propose a Mixed Reality (MR) application to support laboratory lectures in STEM distance education. It was designed following a methodology extendable to diverse STEM laboratory lectures. We formulated this methodology considering the main issues found in the literature that limit MR’s use in education. Thus, the main design features of the resulting MR application are students’ and teachers’ involvement, use of not distracting graphics, integration of traditional didactic material, and easy scalability to new learning activities. In this work, we present how we applied the design methodology and used the framework for the case study of an engineering course to support students in understanding drawings of complex machines without being physically in the laboratory. We finally evaluated the usability and cognitive load of the implemented MR application through two user studies, involving, respectively, 48 and 36 students. The results reveal that the usability of our application is “excellent” (mean SUS score 84.7), and it is not influenced by familiarity with Mixed Reality and distance education tools. Furthermore, the cognitive load is medium (mean NASA TLX score below 29) for all four learning tasks that students can accomplish through the MR application.

Keywords: augmented and virtual reality | distance education and online learning | improving classroom teaching | mixed reality | mobile learning

Abstract: This work investigates the possibility of using a novel “minimal AR” authoring approach to optimize the visual assets used in augmented reality (AR) interfaces to convey work instructions in manufacturing. In the literature, there are no widely supported guidelines for the optimal choice of visual assets (e.g., CAD models, drawings, and videos). Therefore, to avoid the risk of having AR technical documentation based only on the author’s preference, our work proposes a novel authoring approach that enforces the minimal amount of information to accomplish a task. Minimal AR was tested through a simulated AR LEGO-based assembly task. The performance (completion time, mental workload, errors) of 40 users was evaluated with 4 combinations of visual assets in 4 tasks with an increasing amount of information needed. The main result is that visual assets with an excess of information do not significantly increase performance. Therefore, the location of a specified object should be “minimally” authored by an auxiliary model (e.g., a circle and an arrow). For identifying an object within a couple, color coding is preferred to using additional visual assets. If more than two objects must be identified, a drawing visual asset is also needed. Only when the orientation of a selected object must be conveyed, animated product models are required. These insights could be helpful for an optimal design of AR work instructions in a wide range of industrial fields.

Keywords: Authoring | Industrial augmented reality | Industrial metaverse | Minimal information | Visual asset | Work instruction

Abstract: Industrial Augmented Reality (iAR) has demonstrated its advantages to communicate technical information in the fields of maintenance, assembly, and training. However, literature is scattered among different visual assets (i.e., AR visual user interface elements associated with a real scene). In this work, we present a systematic literature review of visual assets used in these industrial fields. We searched five databases, initially finding 1757 papers. Then, we selected 122 iAR papers from 1997 to 2019 and extracted 348 visual assets. We propose a classification for visual assets according to (i) what is displayed, (ii) how it conveys information (frame of reference, color coding, animation), and, (iii) why it is used. Our review shows that product models, text and auxiliary models are, in order, the most common, with each most often used to support operating, checking and locating tasks respectively. Other visual assets are scarcely used. Product and auxiliary models are commonly rendered world-fixed, color coding is not used as often as expected, while animations are limited to product and auxiliary model. This survey provides a snapshot of over 20 years of literature in iAR, useful to understand established practices to orientate in iAR interface design and to present future research directions.

Keywords: Augmented reality | industry | reviews | user interfaces | visualization

Abstract: Although Virtual Reality Social Skills Training has proven its effectiveness in treating psychiatric disorders, this VR application field is still under-researched for two main reasons. The first one is the unavailability of low-cost VR technologies with sufficient computational capacity needed to render realistic Virtual Environments. The second one consists of the need for specialized VR application developers, usually far from the mental health research field. The recent diffusion of low-cost stereoscopic viewers and the introduction of easy and fast VR content authoring systems, such as Cinematic Virtual Reality (CVR), allow overcoming these limitations. CVR makes it possible to capture real scenes through 360 cameras, augment them with additional virtual objects, and finally immerse the user in these synthetic but highly immersive environments. We present the design and the features of the Entellect360 prototype -an innovative tool supporting the rehabilitation process of subjects affected by schizophrenia. It exploits CVR technology to create Virtual Environments aimed at the rehabilitation of psychiatric patients. The Entellect360 features allow for rehabilitation sessions and patient-performance data-collection even under conditions of social distancing. We also explain the experimental protocol and the validation procedure the prototype will undergo to assess its effectiveness.

Keywords: 360-degree virtual reality | Cognitive rehabilitation | Human-computer interaction | Mental health | Social skills training

Abstract: The introduction of the new generation of Head Mounted Displays (HMD) makes users’ experiences in Mixed Reality (MR) environments more engaging. However, these devices still have a limited field of view, which negatively affects the spatial localization process of virtual objects in the 3D environment. The literature presents several visualization techniques to address this issue, but they currently have several drawbacks, such as visual clutter, occlusion of the real scene, high user workload, and there is still no visualization technique that solves such issues definitively. Therefore, inspired by the gaming industry, we present CompassbAR a visualization technique for out-of-view objects. CompassbAR encodes the position of all out-of-view objects surrounding the user, in a 2D bar positioned at the top of the field of view. In addition, we propose a validation procedure and metrics that aim to evaluate the ability of the CompassbAR visualization technique to guide users towards the out-of-view objects.

Keywords: Head-mounted display | Mixed Reality | Visualization techniques

Abstract: Mixed Reality (MR) could help students in the understanding of complex concepts as well as increase their motivation in the learning process. In this work, our aim is to propose a MR application for the support of engineering students in the understanding of assembly drawings of complex machines. We presented the application of our design methodology for this case study. Then, based on the results of a user study with a sample of students, we tried to improve the usability and the user experience of the MR application, proposing an updated version. The usability of the revised application was in the range “good-excellent” (mean SUS score 77.0). We also presented the lessons learned in this case study, that can be a starting point for a renewal of consolidated didactic processes aiming at future application of MR in other STEM courses.

Keywords: Augmented and virtual reality | Distance education and online learning | Improving classroom teaching | Mixed Reality | Mobile learning

Abstract: In this work, a Coarse-Grained Lattice Spring Model to characterize the mechanical behavior of human mesenchymal stem cells subjected to nanoindentation measurements is presented. The model simulated the action of adhesive structures acting on cells, necessary for attaching them to a substrate, and a nanoindentation process, performed by means of an atomic force microscope with a spherical tip. Cells were hypothesized to behave as elastic materials and the model included several subcellular components such as cell cortex and cytoskeleton. The lattice spring model was integrated within an optimization algorithm that iteratively compared the force-indentation curve numerically predicted to the data experimentally obtained, until a best fit condition was reached. The computed mechanical properties of the cell were compared to those obtained via the Hertz contact theory and finite element modelling, showing a good agreement. The proposed lattice spring model appears as a promising tool that can be used, with a very low computational cost, to characterize cell materials and other biological materials.

Keywords: Cell mechanical properties | Lattice spring models | Nanoindentation | Stem cells

Abstract: The design of complex manufacturing systems (CMSs) is challenging, because of the requirements of efficiency, safety, and ergonomics, and the need of optimizing resources, i.e., space, machines, operators, and data. Virtual reality (VR) – one of the promising technologies at the base of Industry 4.0 – is able to address the design issues of CMSs, and even decrease costs and time when employed from the initial conception to the final validation of production lines, since it facilitates their virtual commissioning, i.e., it enables the full verification of systems and related components by virtual inspection and tests. Despite the above advantages, VR is still rarely used in the design of CMSs, and there is no standard VR approach in industry yet. In addition, the related scientific literature is scarce and often limited to small or simplified cases. To fill this gap, this work presents a novel VR-based approach for designing CMSs, composed of four phases: Three-dimensional CAD Export, Model Import, Scene Creation, and VR Review. The proposed approach is applied to a real industrial use case related to the virtual commissioning of an electric axles production line and it is evaluated through a questionnaire from industry professionals. The case study shows that using the VR technology enhanced the technical communication between experts in the teamwork, and it was particularly effective in finding ergonomics flaws like issues in visibility, reach, and posture using a virtual golden zone. In addition, all users found the VR interaction enjoyable and easy to learn, and beginner users perceived a comparable workload as advanced users.

Keywords: Complex manufacturing systems | Human computer interaction | Industry 4.0 | System design | Virtual commissioning | Virtual reality

Abstract: Despite the increasing degree of automation in industry, manual or semi-automated are commonly and inevitable for complex assembly tasks. The transformation to smart processes in manufacturing leads to a higher deployment of data-driven approaches to support the worker. Upcoming technologies in this context are oftentimes based on the gesture-recognition, − monitoring or–control. This contribution systematically reviews gesture or motion capturing technologies and the utilization of gesture data in the ergonomic assessment, gesture-based robot control strategies as well as the identification of COVID-19 symptoms. Subsequently, two applications are presented in detail. First, a holistic human-centric optimization method for line-balancing using a novel indicator–ErgoTakt–derived by motion capturing. ErgoTakt improves the legacy takt-time and helps to find an optimum between the ergonomic evaluation of an assembly station and the takt-time balancing. An optimization algorithm is developed to find the best-fitting solution by minimizing a function of the ergonomic RULA-score and the cycle time of each assembly workstation with respect to the workers’ ability. The second application is gesture-based robot-control. A cloud-based approach utilizing a generally accessible hand-tracking model embedded in a low-code IoT programming environment is shown.

Keywords: assembly | gesture-based control | Gesture-Based monitoring | manufacturing

Abstract: Sailing navigation is an activity that requires acquiring and processing information from the surrounding environment. The advancement of technology has enabled sailboats to have an increasing number of onboard sensors that make sailing more user-friendly. However, data provided by these sensors are still visualized on 2D digital displays that imitate traditional analog interfaces. Although these displays are strategically placed on the sailboat, the user needs to divert attention from the primary navigation task to look at them, thus spending a significant amount of cognitive resources. AR-based technologies have the potential to overcome these limitations by displaying information registered in the real environment, but there are no studies in the literature for validating the effectiveness of this technology in the field of sailing. Thus, we designed a head-mounted display AR-based interface to assist users in monitoring wind data to avoid user diversion from the primary task of sailing. We conducted a user study involving 45 participants in an Immersive Virtual Reality simulated environment. We collected objective and subjective measures to compare the AR-based interface with a traditional data visualization system. The AR-based interface outperformed the traditional data visualization system regarding reaction time, cognitive load, system usability, and user experience.

Keywords: Augmented reality | Cognitive load | Human–computer interaction | Nautical | Sailing | User study

Abstract: In the future, many activities will be carried out in the Metaverse: hybrid offices and video-based education are just some examples. The way research is carried out could change, too. In this context, this work investigates the possibility of simulating Augmented Reality (AR) user studies on information presentation in a virtual environment. Organizing an industrial setup is complex; thus, most studies are executed in laboratories. However, lab experiments present limitations, e.g., the number and variety of participants and the availability of facilities. User studies may also be carried out by exploiting simulated AR, as an initial step for the Metaverse, where people are connected regardless of their location. This alternative could be used to carry out experiments on AR information presentation to solve common issues, such as the lack of physical equipment to perform component location tasks and the long time required to collect a large sample of users. Indeed, researchers could propose CAD models with information that simulates the same visual realism achieved with true AR. Moreover, multiple tests could be conducted in parallel by not relying on a limited amount of physical equipment per user. In this work, we developed and evaluated a desktop-simulated testing environment (DSTE) to conduct AR information presentation experiments remotely. We applied it in a pilot user study, revealing that the proposed DSTE was effective for the related research goals. Furthermore, 40 participants reported a positive user experience. The evaluation confirms that using a DSTE is promising for collecting and analyzing data from a wide range of people.

Keywords: AR simulation | industrial metaverse | information presentation | user interaction | user study

Abstract: The choice of furniture in a retail store is usually based on a product catalog and simplistic product renderings with different configurations. We present a preliminary field study that tests a Multi-Sensory In-Store Virtual Reality Customer Journey (MSISVRCJ) through a virtual catalog and a product configurator to support furnishings sales. The system allows customers to stay immersed in the virtual environment (VE) while the sales expert changes the colors, textures, and finishes of the furniture, also exploring different VEs. In addition, customers can experience realistic tactile feedback with in-store samples of furniture they can test. The journey is implemented for a furniture manufacturer and tested in a flagship store. Fifty real customers show positive feedback in terms of general satisfaction, perceived realism, and acceptance. This method can increase purchase confidence, reduce entrepreneurial costs, and leverage in-store versus online shopping.

Keywords: customer journey | furniture | in-store | industrial design | multisensory | retailing | virtual reality

Abstract: Drill tool positioning in dental implantology is a challenging task requiring 5DOF precision as the rotation around the tool axis is not influential. This work improves the quasi-static visual elements of the state-of-the-art with a novel Augmented Collimation Widget (ACW), an interactive tool of position and angle error visualization based on the gestalt reification, the human ability to group geometric elements. The user can seek in a quick, pre-attentive way the collimation of five (three positional and two rotational) error component widgets (ECWs), taking advantage of three key aspects: component separation and reification, error visual amplification, and dynamic hiding of the collimated components. We compared the ACW with the golden standard in a within-subjects (N=30) user test using 32 implant targets, measuring the time, error, and usability. ACW performed significantly better in positional (+19%) and angular (+47%) precision accuracy and with less mental demand (-6%) and frustration (-13%), but with an expected increase in task time (+59%) and physical demand (+64%). The interview indicated the ACW as the main preference and aesthetically more pleasant than GSW, candidating it as the new golden standard for implantology, but also for other applications where 5DOF positioning is key.

Keywords: Augmented Reality | augmented tool | dental implantology | gestalt principles | spatial orientation | visualization design

Abstract: Immersive Vimial Reality (IVR) training offers the capability to industrial workers to acquire skills and address complex tasks by immersing them in a safe and controlled virtual environment (VE). However, in the literature, IVR training is mainly based on principles of standardization and efficiency without considering the operators' well-being. A novel design approach consists of the introduction in the VE of Positive Computing to improve workers' well-being by applying the Biophilia hypothesis. In this work, we explored the possibility of introducing biophilic elements in a VE training scenario that would support psychological well-being and human potential. However, the introduction of virtual elements not related to the training task may distract operators, impairing their performance. We selected as a training scenario the assembly of a real truck engine. It is accomplished in a workstation, and operators do not interact with the surrounding VE. Therefore, we placed the training area into four different types of VEs: 3D Minimal (MIN), 3D Minimal Biophilic enriched (MIN+BIO), 3D Realistic (REAL), and 3D Realistic Biophilic enriched (REAL+BIO). We compared the MIN and REAL scenarios with the respective biophilic enriched scenarios. The performance of 40 participants was evaluated in terms of completion time, object fixation time, training task accuracy, knowledge accuracy, cognitive load, and user experience. The results revealed that introducing biophilic elements in a VR training environment attracts users' attention in the idle phase of the training. In contrast, they keep concentrating on the task without worsening their performance during the task accomplishment

Keywords: Biophilia Hypothesis | Industrial Training | Positive Computing | Virtual Reality

Abstract: Complex manufacturing systems are recently undergoing a green revolution due to manufacturing customization towards sustainable products. A key enabler for the implementation of green and energy efficient production is simulation-based design, which supports system engineers and designers in making decision choices aimed at enhancing the performance of smart and sustainable production. In this context, this work proposes a simulation approach to support the design of the layout and operation of automated guided vehicles (AGVs) in complex production lines. In particular, a case study related to the assembly of electric axles for heavy-duty vehicles is presented: a scenario analysis implemented in the Plant Simulation platform is used to determine the optimal configuration of AGVs in terms of number of vehicles and operation (e.g., definition of charging strategies, scheduling of charging stops, routing). The simulation results first show that the reduction of the AGVs' energy consumption and the increase of production throughput are competing criteria; second, the choice of AGV charging strategies has a significant influence on the energy consumption as well as on the productivity performance.

Keywords: automated guided vehicle (AGV) | Complex manufacturing systems | discrete event simulation | sustainable and efficient manufacturing | what-if analysis

Abstract: [No abstract available]

Abstract: This study investigates the use of augmented reality technology (AR) in the field of maritime navigation and how researchers and designers have addressed AR data visualisation. The paper presents a systematic review analysing the publication type, the AR device, which information elements are visualised and how, the validation method and technological readiness. Eleven AR maritime solutions identified from scientific papers are studied and discussed in relation to previous navigation tools. It is found that primitive information such as course, compass degrees, boat speed and geographic coordinates continue to be fundamental information to be represented even with AR maritime solutions.

Keywords: augmented reality | data visualisation | human-computer interaction | maritime

Abstract: The procedure commonly adopted to characterize cell materials using atomic force microscopy neglects the stress state induced in the cell by the adhesion structures that anchor it to the substrate. In several studies, the cell is considered as made from a single material and no specific information is provided regarding the mechanical properties of subcellular components. Here we present an optimization algorithm to determine separately the material properties of subcellular components of mesenchymal stem cells subjected to nanoindentation measurements. We assess how these properties change if the adhesion structures at the cell-substrate interface are considered or not in the algorithm. In particular, among the adhesion structures, the focal adhesions and the stress fibers were simulated. We found that neglecting the adhesion structures leads to underestimate the cell mechanical properties thus making errors up to 15%. This result leads us to conclude that the action of adhesion structures should be taken into account in nanoindentation measurements especially for cells that include a large number of adhesions to the substrate.

Keywords: Cell cortex | Cell mechanics | Cytoskeleton | Finite element method | Focal adhesion | Stress fibers

Abstract: Today’s sailing visualization instruments struggle to cope with the increasing number of onboard sensors, automation, artificial intelligence, and the high dy-namism of the crew. Current solutions scatter multiple displays all over the boat, both inside and outside, potentially reducing usability and increasing costs. This work presents a systematic review of augmented reality (AR) as an integral solution for sailing data visualization, which revealed four scientific papers and eight commercial products. We analyzed the publication type, the AR hardware, what and how information is presented using AR, the validation method (if present), and the technological readiness. We defined the technical requirements needed for the AR device for sailing and distinguished a first generation of commercial solutions based on head-up displays from a second one based on proper augmentation with stereo head-mounted displays. The displayed information elements are limited in number and are commonly 2-D graphics (e.g., text and symbols) with a screen-relative frame of reference (as opposed to body-or world-relative). The most visu-alized elements are heading (10) followed by wind direction (8), boat speed (7) compass (7), and wind speed (7). We also found that most of the solutions lack critical evaluation. We conclude that AR has the potential to integrate sailing data from different systems and to improve accessibility, situation awareness, and safety for a large group of users. However, the main limitations are the lack of AR head-mounted displays suitable or adaptable for sailing conditions, an extensive exploration of 3-D interface elements, and an adequate number of usability studies in the scientific literature.

Keywords: Augmented reality | Data visualization | Human-computer interaction | Nautical instruments | Sailing

Abstract: The knowledge of the mechanical properties is the starting point to study the mechanobiology of mesenchymal stem cells and to understand the relationships linking biophysical stimuli to the cellular differentiation process. In experimental biology, Atomic Force Microscopy (AFM) is a common technique for measuring these mechanical properties. In this paper we present an alternative approach for extracting common mechanical parameters, such as the Young's modulus of cell components, starting from AFM nanoindentation measurements conducted on human mesenchymal stem cells. In a virtual environment, a geometrical model of a stem cell was converted in a highly deformable Coarse-Grained Elastic Network Model (CG-ENM) to reproduce the real AFM experiment and retrieve the related force-indentation curve. An ad-hoc optimization algorithm perturbed the local stiffness values of the springs, subdivided in several functional regions, until the computed force-indentation curve replicated the experimental one. After this curve matching, the extraction of global Young's moduli was performed for different stem cell samples. The algorithm was capable to distinguish the material properties of different subcellular components such as the cell cortex and the cytoskeleton. The numerical results predicted with the elastic network model were then compared to those obtained from hertzian contact theory and Finite Element Method (FEM) for the same case studies, showing an optimal agreement and a highly reduced computational cost. The proposed simulation flow seems to be an accurate, fast and stable method for understanding the mechanical behavior of soft biological materials, even for subcellular levels of detail. Moreover, the elastic network modelling allows shortening the computational times to approximately 33% of the time required by a traditional FEM simulation performed using elements with size comparable to that of springs.

Keywords: Atomic force microscopy | Cell material characterization | Elastic network model | Meshless methods

Abstract: This paper presents a novel Augmented Reality (AR) interface for Head Mounted Display HMD, specifically for sailing navigation. Compared to literature and the commercial solutions available, the novelty is to use boat-referenced 3D graphics. It allows representing wind direction and intensity, heading with monochrome green elements. Furthermore, we carried out a user validation study. We implemented a virtual simulator including a sailboat, the marine environment (i.e., sea, sky, marine traffic, and sounds), and the presented interface as AR overlay. We evaluated the effectiveness of the wind representation of the AR interface through an online questionnaire based on a video simulation and asking the user to imagine it as the result of an AR visualization. We defined one test scenario with wind variations and a distracting element (i.e., a crossing vessel). 75 sailors (59% experts, with more than 50 sailing days per year) participated in the questionnaire, and most of them (63%) considered the video effective at simulating the AR interface. In addition, 75% are ready to wear an AR device during sailing. Also, the usability (SUS questionnaire) and the user experience (UEQ) results provided positive results.

Keywords: Augmented reality | Human-computer interaction | Nautical | Sailing | user test

Abstract: This research investigates the application of positive computing principles to Virtual Reality (VR) training scenarios where the Virtual Environment (VE) has not a direct influence on operator learning. We propose to place the 3D models of the only objects needed for the task in a VE consisting of 360° panoramas of natural environments. We made a preliminary evaluation of the user experience which showed that the hedonic quality is significantly higher with this VE than a 3D modeled empty room. However, we also observed a reduction of the pragmatic quality, due to potential distractions. Thus, further research is needed to demonstrate the efficacy of our positive computing approach in training against a traditional one based on the faithful 3D reproduction of the real environment.

Keywords: Industrial Training | Positive Computing | Virtual Reality

Abstract: Virtual reality is a candidate to become the preferred interface for architectural design review, but the effectiveness and usability of such systems is still an issue. We put together a multidisciplinary team to implement a test methodology and system to compare VR with 2D interaction, with a coherent test platform using Rhinoceros as industry-standard CAD software. A direct and valid comparison of the two setups is made possible by using the same software for both conditions. We designed and modeled three similar CAD models of a 2 two-story villa (1 for the training and 2 for the test) and we implanted 13 artificial errors, simulating common CAD issues. Users were asked to find the errors in a 10 minutes fixed-Time session for each setup respectively. We completed our test with 10 students from the design and architecture faculty, with proven experience of the 2D version of the CAD. We did not find any significant differences between the two modalities in cognitive workload, but the user preference was clearly towards VR. The presented work may provide interesting insights for future human-centered studies and to improve future VR architectural applications.

Keywords: Architecture | design review | evaluation | user preference | Virtual Reality | workload

Abstract: The research presented in this contribution aims to investigate user preferences about how to convey information in Industrial Augmented Reality (IAR) interfaces to the user. Our interest is focused on the opinion of potential technical writers of IAR documentation for assembly or maintenance operations. Authoring of IAR interfaces imply a choice among various visual assets, that is influenced by the information type and the AR display used. There are no specific standards in the literature to follow and it is challenging to extract guidelines from the literature. This study gathers preferences of 105 selected users that have knowledge about IAR issues, graphical user interfaces (GUI) designing, and assembly/maintenance procedures. The results of this survey show a great preference for 3D CAD models of components (product model) for almost all the information types. However, some alternative visual assets have also been proposed, such as video and auxiliary models. Contrary to common practices in industry, text was the least preferred visual asset. The insights from this research can help other IAR technical writers in the authoring of their interfaces.

Keywords: Graphic Interface | Industrial Augmented Reality | Manual Assembly | Visual Asset

Abstract: Sailing is a multidisciplinary activity that requires years to master. Recently this sustainable sport is becoming even harder due to the increasing number of onboard sensors, automation, artificial intelligence, and the high performances obtainable with modern vessels and sail designs. Augmented Reality technology (AR) has the potential to assist sailors of all ages and experience level and improve confidence, accessibility, situation awareness, and safety. This work presents our ongoing research and methodology for developing AR assisted sailing. We started with the problem definition followed by a state of the art using a systematic review. Secondly, we elicited the main task and variables using an online questionnaire with experts. Third, we extracted the main variables and conceptualized some visual interfaces using 3 different approaches. As final phase, we designed and implemented a user test platform using a VR headset to simulate AR in different marine scenarios. For a real deployment, we witness the lack of available AR devices, so we are developing one specific headset dedicated to this task. We also envision the possible redesign of the entire boat as a consequence of the introduction of AR technology.

Keywords: Augmented Reality | Human Computer Interaction | Nautical | Sailing | Yacht

Abstract: Since its beginning at the end of 2019, the pandemic spread of the severe acute respiratory syndrome coronavirus 2 (Sars-CoV-2) caused more than one million deaths in only nine months. The threat of emerging and re-emerging infectious diseases exists as an imminent threat to human health. It is essential to implement adequate hygiene best practices to break the contagion chain and enhance society preparedness for such critical scenarios and understand the relevance of each disease transmission route. As the unconscious hand–face contact gesture constitutes a potential pathway of contagion, in this paper, the authors present a prototype system based on low-cost depth sensors able to monitor in real-time the attitude towards such a habit. The system records people’s behavior to enhance their awareness by providing real-time warnings, providing for statistical reports for designing proper hygiene solutions, and better understanding the role of such route of contagion. A preliminary validation study measured an overall accuracy of 91%. A Cohen’s Kappa equal to 0.876 supports rejecting the hypothesis that such accuracy is accidental. Low-cost body tracking technologies can effectively support monitoring compliance with hygiene best practices and training people in real-time. By collecting data and analyzing them with respect to people categories and contagion statistics, it could be possible to understand the importance of this contagion pathway and identify for which people category such a behavioral attitude constitutes a significant risk.

Keywords: Azure kinect | Body tracking | Hygiene best practices | Occupational safety | Pandemics containment | Safety training

Abstract: Despite the wide use of scaffolds with spherical pores in the clinical context, no studies are reported in the literature that optimize the micro-architecture dimensions of such scaffolds to maximize the amounts of neo-formed bone. In this study, a mechanobiology-based optimization algorithm was implemented to determine the optimal geometry of scaffolds with spherical pores subjected to both compression and shear loading. We found that these scaffolds are particularly suited to bear shear loads; the amounts of bone predicted to form for this load type are, in fact, larger than those predicted in other scaffold geometries. Knowing the anthropometric characteristics of the patient, one can hypothesize the possible value of load acting on the scaffold that will be implanted and, through the proposed algorithm, determine the optimal dimensions of the scaffold that favor the formation of the largest amounts of bone. The proposed algorithm can guide and support the surgeon in the choice of a "personalized" scaffold that better suits the anthropometric characteristics of the patient, thus allowing to achieve a successful follow-up in the shortest possible time.

Keywords: Bone tissue engineering | Computational mechanobiology | Geometry optimization | Parametric CAD (Computer aided design) model | Python code

Abstract: This paper investigates the Augmented Reality (AR) technology with a novel approach based on patent research. We searched the USPTO for AR-related granted patents in the period 1993–2018, we selected and manually browse a total of 2,373, we classified them in five key technological classes i.e., display device, tracking, user interaction, application, and system, and we finally analyzed the results. The main contribution of this paper is the investigation of the technological trends, with outcomes that can be useful for researchers and developers for technical steering, but also for policymakers, managers and entrepreneurs for technology scouting and forecasting. Our study found that AR technological development has especially increased in the last decade. In particular, we evidenced a remarkable steady of 82 % annual growth rate of the number of granted patents after 2012. From geographical distribution, we found that North America is the leader (68 %); Asia (18 %) and Europe (13 %) are lagging behind despite dedicated Industry 4.0 policies actuated by the governments. Another nontrivial result is the incoherency between the owners of a high quantity of patents and those highly impacting. In fact, only Microsoft Corporation and Amazon Technologies are at the same time in the top 10 of the most patent-intensive organizations and the top 10 of highly impacting organizations. Moreover, the majority of the patents are owned by companies, albeit some of the highly impacting ones come from universities or research centers. These findings provide theoretical, managerial, and policy implications for future research activities in the AR domain.

Keywords: Application | AR systems | Augmented reality | Display device | Geographical distribution | Holograms | Human-machine interaction | Immersive technologies | Industry 4.0 | Interactive technologies | Patent analysis | Presence | Review | Technological innovation | Technological trend | Technology forecasting | Technology scouting | Tracking | User interaction | Visual overlay

Abstract: Technical documentation is evolving from static contents presented on paper or via digital publishing to real-time on-demand contents displayed via virtual and augmented reality (AR) devices. However, how best to provide personalized and context-relevant presentation of technical information is still an open field of research. In particular, the systems described in the literature can manage a limited number of modalities to convey technical information, and do not consider the 'people' factor. Then, in this work, we present a Context-Aware Technical Information Management (CATIM) system, that dynamically manages (1) what information as well as (2) how information is presented in an augmented reality interface. The system was successfully implemented, and we made a first evaluation in the real industrial scenario of the maintenance of a hydraulic valve. We also measured the time performance of the system, and results revealed that CATIM performs fast enough to support interactive AR.

Keywords: Augmented reality | Context-aware | Human-centered design | Human-computer interaction | Industrial | Information manager | Maintenance | Technical documentation

Abstract: In spite of the rather large use of the fused deposition modeling (FDM) technique for the fabrication of scaffolds, no studies are reported in the literature that optimize the geometry of such scaffold types based on mechanobiological criteria. We implemented a mechanobiology-based optimization algorithm to determine the optimal distance between the strands in cylindrical scaffolds subjected to compression. The optimized scaffolds were then 3D printed with the FDM technique and successively measured. We found that the difference between the optimized distances and the average measured ones never exceeded 8.27% of the optimized distance. However, we found that large fabrication errors are made on the filament diameter when the filament diameter to be realized differs significantly with respect to the diameter of the nozzle utilized for the extrusion. This feasibility study demonstrated that the FDM technique is suitable to build accurate scaffold samples only in the cases where the strand diameter is close to the nozzle diameter. Conversely, when a large difference exists, large fabrication errors can be committed on the diameter of the filaments. In general, the scaffolds realized with the FDM technique were predicted to stimulate the formation of amounts of bone smaller than those that can be obtained with other regular beam-based scaffolds.

Keywords: Biomaterials | Geometry optimization | Mechanobiology | Scaffold design | Tissue engineering

Abstract: Although the increasing use of automation in industry, manual assembly stations are still common and, in some situations, even inevitable. Current practice in manual assembly lines is to balance them using the takt-time of each workstation and harmonize it. However, this approach mostly does not include ergonomic aspects and thus it may lead to workforce musculoskeletal disorders, extended leaves, and demotivation. This paper presents a holistic human-centric optimization method for line balancing using a novel indicator the ErgoTakt. ErgoTakt improves the legacy takt-time and helps to find an optimum between the ergonomic evaluation of an assembly station and its balance in time. The authors used a custom version of the ErgoSentinel Software and a Microsoft Kinect depth camera to perform online and real-time ergonomic assessment. An optimization algorithm is developed to find the best-fitting solution by minimizing a function of the ergonomic RULA-value and the cycle time of each assembly workstation with respect to the worker's ability. The paper presents the concept, the system-setup and preliminary evaluation of an assembly scenario. The results demonstrate that the new approach is feasible and able to optimize an entire manual assembly process chain in terms of both, economic aspects of a well-balanced production line as well as the ergonomic issue of long term human healthy work.

Keywords: Assembly digitalization | Ergonomic assessment | Line balancing

Abstract: The enabling technologies of the Industry 4.0 program can support the smart factory of the future to face the challenges related to their sustainable growth. In particular, given the progressive ageing of the population, it is mandatory to develop systems able to preserve operators' wellbeing and to prevent the incidence of work-related musculoskeletal disorders. By exploiting a recently introduced low-cost sensor we developed and validated a reliable prototype for automatic assessment of ergonomic postural risk in the factory shopfloor. Encouraged by the results of the validation process, we enhanced the prototype functionalities. The tool will serve both as a monitoring system for the evaluation of postural risk and a training system for increasing operators' awareness. In this paper, we describe the design of the prototype and the enhanced functionalities of the final version, - the ErgoSentinel.

Keywords: Ergonomics | I4.0 | Kinect® V2 | Postural risk assessment | RULA | Sustainable work

Abstract: The aim of this study is to understand if the shape of a cell can affect the characterization process of the mechanical properties via nanoindentation measurements. The characterization of the cell material by atomic force microscopy, in fact, traditionally implements the Hertz contact theory that is based on hypotheses not satisfied in the contact Atomic Force Microscope tip/cell and that do not take into account the actual cell morphology. In previous experimental studies, the mechanical properties of colorectal cancer cells differently shaped (rounded or elongated cells) and sized were determined via nanoindentation measurements. Implementing the Hertz theory, the authors found that differences in mechanical properties exist between the different cell lines with different shape. At this point, the question that can be raised is the following. Is it possible to state that this difference depends on the differences intrinsically existing between the mechanical properties of the investigated cells? Or, this difference can be justified with the difference in cells shape? In other words, the differences seen with the Hertz theory can depend on the fact that the cell shape was not taken into account. To respond to this question, the nanoindentation process of the different colorectal cancer cells was simulated via the finite element method. The finite element models reproducing the cells morphology were integrated into a numerical optimization algorithm that cyclically perturbs the cell mechanical properties until the difference between the force-indentation curve retrieved numerically and that obtained experimentally becomes smaller than an a priori fixed ε value. Once this occurs, the optimization algorithm stops and gives in output the optimal cell material properties. Interestingly, we found that the mechanical properties obtained via the Hertz contact theory are significantly different with respect to those computed with the proposed approach. Furthermore, we found that the material properties of the rounded cells are intrinsically different with respect to those of the elongated ones. The proposed approach provides new insights on the cell mechanobiology and on the effect of cell shape on the specific tasks in cancer growth and invasion.

Keywords: Cell material characterization | Cell modelling | Cell shape

Abstract: Augmented Reality is considered one of the most promising technologies for Industry 4.0. Augmented Reality allows to display the needed information at the right time and to locate it in the desired space, superimposing it to the real world. In this way, it could simplify the work of industrial operators in a variety of tasks, from planning and commissioning to assembly and maintenance. Despite the growing research interest and efforts for the development of Augmented Reality applications and technologies for the industrial domain, Augmented Reality is still rarely used in real industrial procedures, often remaining at a conceptual level. In fact, developers fail to completely answer the actual needs of industries and workers because of a lack of knowledge of the context and the absence of guidelines to drive the design and development of Augmented Reality applications. One of the open issues is the choice of the proper visualization methods to display technical information in Augmented Reality, which is not trivial. Both the paper-based documentation, based on text and illustrations, and digital documentation, including CAD models and image or video-based tutorials, present different criticalities when adapted to the Augmented Reality technology. Other visual material has been developed specifically to be used in Augmented Reality, but it is difficult to use because of a lack of standards which are instead present for the former paper-based and digital documentation. In this work, we categorize and compare different Augmented Reality visual assets, illustrating their advantages and disadvantages and providing directions for future research.

Keywords: Augmented Reality | Graphical User Interface | Industry 4.0 | Technical documentation

Abstract: By combining load adaptive algorithms with mechanobiological algorithms, a computational framework was developed to design and optimize the microarchitecture of irregular load adapted scaffolds for bone tissue engineering. Skeletonized cancellous bone-inspired lattice structures were built including linear fibers oriented along the internal flux of forces induced by the hypothesized boundary conditions. These structures were then converted into solid finite element models, which were optimized with mechanobiology-based optimization algorithms. The design variable was the diameter of the beams included in the scaffold, while the design objective was the maximization of the fraction of the scaffold volume predicted to be occupied by neo-formed bony tissue. The performance of the designed irregular scaffolds, intended as the capability to favor the formation of bone, was compared with that of the regular ones based on different unit cell geometries. Three different boundary and loading conditions were hypothesized, and for all of them, it was found that the irregular load adapted scaffolds perform better than the regular ones. Interestingly, the numerical predictions of the proposed framework are consistent with the results of experimental studies reported in the literature. The proposed framework appears to be a powerful tool that can be utilized to design high-performance irregular load adapted scaffolds capable of bearing complex load distributions.

Keywords: finite element method | irregular and regular scaffolds | load adaptive algorithms | mechanobiological algorithms | robustness of optimized structures | structural optimization algorithms

Abstract: Due to the recent advances in technologies for gesture recognition, midair gestures can be considered the interface of the future in a large number of applications. However, designing effective interfaces with midair gestures is not an easy task because the design is application dependent and it must fulfill many requirements at the same time. Despite the availability of general guidelines in the literature, clear and well-established procedures for the optimal design of midair gesture-based interfaces are, to date, not available and remain an open issue. The main contribution of this paper is a user-centered modular framework, which integrates existing and novel methods. It supports the designer considering multiple aspects including ergonomics, memorability, and specific user requirements tailored to the application scenario. The framework involves three design steps and a final validation step, also supported by dedicated software. We tested with success the proposed framework in an industrial case study, where technicians must easily access technical information by browsing digital manuals during maintenance operations.

Keywords: Consumed endurance (CE) | ergonomics | gesture vocabulary | midair gesture interface | user-centered elicitation approach

Abstract: Blepharospasm (BSP) is an adult-onset focal dystonia with phenomenologically heterogeneous effects, including, but not limited to, blinks, brief or prolonged spasms, and a narrowing or closure of the eyelids. In spite of the clear and well-known symptomatology, objectively rating the severity of this dystonia is a rather complex task since BSP symptoms are so subtle and hardly perceptible that even expert neurologists can rate the gravity of the pathology differently in the same patients. Software tools have been developed to help clinicians in the rating procedure. Currently, a computerised video-based system is available that is capable of objectively determining the eye closure time, however, it cannot distinguish the typical symptoms of the pathology. In this study, we attempt to take a step forward by proposing a neural network-based software able not only to measure the eye closure, time but also to recognise and count the typical blepharospasm symptoms. The software, after detecting the state of the eyes (open or closed), the movement of specific facial landmarks, and properly implementing artificial neural networks with an optimised topology, can recognise blinking, and brief and prolonged spasms. Comparing the software predictions with the observations of an expert neurologist allowed assessment of the sensitivity and specificity of the proposed software. The levels of sensitivity were high for recognising brief and prolonged spasms but were lower in the case of blinks. The proposed software is an automatic tool capable of making objective ‘measurements’ of blepharospasm symptoms.

Keywords: Blepharospasm | Blepharospasm rating scale | Eye closure time | Focal dystonia | Neural network topology optimisation

Abstract: Augmented Reality (AR), is one of the most promising technology for technical manuals in the context of Industry 4.0. However, the implementation of AR documentation in industry is still challenging because specific standards and guidelines are missing. In this work, we propose a novel methodology for the conversion of existing “traditional” documentation, and for the authoring of new manuals in AR in compliance to Industry 4.0 principles. The methodology is based on the optimization of text usage with the ASD Simplified Technical English, the conversion of text instructions into 2D graphic symbols, and the structuring of the content through the combination of Darwin Information Typing Architecture (DITA) and Information Mapping (IM). We tested the proposed approach with a case study of a maintenance manual of hydraulic breakers. We validated it with a user test collecting subjective feedbacks of 22 users. The results of this experiment confirm that the manual obtained using our methodology is clearer than other templates.

Keywords: Augmented reality | Industry 4.0 | Maintenance support | Technical documentation

Abstract: Technical information presentation is evolving from static contents presented on paper or via digital publishing to real-time context-aware contents displayed via virtual and augmented reality devices. We present a Context-Aware Technical Information Management system (CATIM), that dynamically manages (1) what information as well as (2) how information is presented in an augmented reality interface. CATIM acquires context data about activity, operator, and environment, and then based on these data, proposes a dynamic augmented reality output tailored to the current context. The system was successfully implemented and preliminarily evaluated in a case study regarding the maintenance of a hydraulic valve.

Keywords: Aware information | Context | Industrial augmented reality | Technical information manager

Abstract: In this work, we present an Augmented Reality (AR) application for handheld devices that support operators in information retrieval tasks in maintenance procedures in the context of Industry 4.0. Indeed, using AR allows the integration of knowledge-based information, traditionally used by operators and mainly provided in the form of technical drawings, and data available from sensors on the equipment. This approach is suggested by companies, especially Small and Medium-sized Enterprises, that want a gradual introduction of Industry 4.0 technologies within their established practices. We implemented a prototype of the application for the case study of a milling plant. The application augments on a Piping and Instrumentation Diagram (P&ID) of the plant some virtual interactive graphics (hotspots) referenced to specific components drawn. Component data are retrieved, through a user interface, directly from the factory database and displayed on the screen. We evaluated the application through a user study aimed at comparing the AR application with the current practice, based on paper documentation, for an information retrieval task within a maintenance procedure. Results of the study revealed that AR is effective for this task in terms of task time reduction and usability. The AR application was tested both with a tablet and a smartphone, but results revealed that using tablet does not improve user performance in terms of task time, error rate, and usability.

Keywords: Augmented Reality | Industry 4.0 | Information retrieval | Maintenance | User evaluation

Abstract: In this paper we report a study that aims to highlight the potentialities of the combined use of both digital and manipulative artefacts to construct and conceptualize mathematical meanings related to the notion of translation. The research hypothesis of our study is that, the alternating use of a digital and a manipulative artefact foster synergically the construction of mathematical meanings. Both the design and the analysis of data is framed by the Theory of Semiotic Mediation in a Vygotskijan perspective. The study involved a class of 20 students, aged 13–14, of a secondary school in the Apulia Region, Italy. Data collection of the study is based on student interaction transcriptions during experimental task execution, written answers to given questions, and finally the transcripts and video analysis of the collective discussions concluding each experimental cycle.

Keywords: Digital artefact | Interaction | Semiotic mediation | Synergy | Translation

Abstract: In this work, we present an Augmented Reality framework for handheld devices that enhance users in the comprehension of plant information traditionally conveyed through printed Piping and Instrumentation Diagrams (P&ID). The proposed framework augments on the P&ID of a plant some virtual interactive graphics (hotspots) referenced to specific components drawn on the P&ID. In this way, it is possible to easily find all the components belonging to the same category (e.g., all the pumps). By tapping, on the tablet screen, on a single hotspot further multimedia information can be displayed: Technical data, 3D CAD model of the component, and 360° images of the plant section. The application is connected to the factory database where all the information associated with the plant components is stored. We used, as a case study, the cleaning section of a milling plant. With the tool presented in this work, technicians will be able to find information updated and in less time, so reducing the intervention time and increasing the accuracy of the operations. Furthermore, the cognitive load associated with the task of understanding the plant is highly reduced through the use of virtual information displayed using Augmented Reality.

Keywords: Augmented Reality | Industrial plant | Industry 4.0 | P&ID | Technical information

Abstract: Scaffolds are porous biomaterials that serve to replace missing portions of bone. Scaffolds must possess a proper geometry and hence have to be adequately designed to correctly undergo to the load and to favor the differentiation of the mesenchymal stem cells invading it, into osteoblasts. It is commonly known that scaffold geometry affects the quality of the regenerated bone creating within the scaffold pores. Scaffold properly designed trigger favorable values of biophysical stimuli that are responsible for the reactions cascade leading to the bone formation. In this paper an optimization algorithm is proposed that, based on mechano-regulation criteria, identifies the optimal geometry of scaffolds, i.e. the geometry that favors the formation of the largest amounts of bone in the shortest time. In detail, the algorithm, written in the Matlab environment, incorporates parametric finite element models of different scaffold types, a computational mechanobiological model and structural optimization routines. The scaffold geometry is iteratively perturbed by the algorithm until the optimal geometry is computed, i.e. the geometry that triggers the most favorable values of the biophysical stimulus which lead to the formation of mature bone. Mesenchymal stem cells were hypothesized to spread within the fracture domain and uniformly occupy the scaffold pores.

Keywords: Hexahedron unit cell | Mechanobiology | Rhombicuboctahedron unit cell | Unit cell geometry

Abstract: Enhancing the performance of scaffolds for bone regeneration requires a multidisciplinary approach involving competences in the fields of Biology, Medicine and Engineering. A number of studies have been conducted to investigate the influence of scaffolds design parameters on their mechanical and biological response. The possibilities offered by the additive manufacturing techniques to fabricate sophisticated and very complex microgeometries that until few years ago were just a geometrical abstraction, led many researchers to design scaffolds made from different unit cell geometries. The aim of this work is to find, based on mechanobiological criteria and for different load regimes, the optimal geometrical parameters of scaffolds made from beam-based repeating unit cells, namely, truncated cuboctahedron, truncated cube, rhombic dodecahedron and diamond. The performance, -expressed in terms of percentage of the scaffold volume occupied by bone-, of the scaffolds based on these unit cells was compared with that of scaffolds based on other unit cell geometries such as: hexahedron and rhombicuboctahedron. A very intriguing behavior was predicted for the truncated cube unit cell that allows the formation of large amounts of bone for low load values and of very small amounts for the medium-high ones. For high values of load, scaffolds made from hexahedron unit cells were predicted to favor the formation of the largest amounts of bone. In a clinical context where medical solutions become more and more customized, this study offers a support to the surgeon in the choice of the best scaffold to be implanted in a patient-specific anatomic region.

Keywords: Beam-based scaffolds | Bone tissue engineering | Diamond | Mechanobiology | Rhombic dodecahedron | Truncated cube | Truncated cuboctahedron | Unit cell

Abstract: One of the most effective strategies that can be adopted to make successful cultural heritage expositions consists in attracting the visitors’ attention and improving their enjoyment/engagement. A mid-air gesture-based Natural User Interface was designed, through the user-centric approach, for the navigation of virtual tours in cultural heritage exhibitions. In detail, the proposed interface was developed to “visit” Murgia, a karst zone lying within Puglia, very famous for its fortified farms, dolines, sinkholes, and caves. Including an “immersive” gesture-based interface was demonstrated to improve the user's experience thus giving her/him the sensation of “exploring” in a seamless manner the wonderful and rather adventurous sites of Murgia. User tests aimed at comparing the implemented interface with a conventional mouse-controlled one confirmed the capability of the proposed interface to enhance the user engagement/enjoyment and to make “more” natural/real, the virtual environment.

Keywords: Gesture vocabulary design | Natural user interface | User-centric approach | Virtual tour

Abstract: The evolution of technical documentation in the age of Industry 4.0 is going towards the use of visual manuals, in particular exploiting Augmented Reality (AR) technology. Traditional manuals are rich of text instructions that in AR applications are not advisable. In fact text occludes the real scene behind and it is an issue for the translation. For this reason, we propose to create and adopt a controlled and exhaustive vocabulary of graphical symbols, to be used in AR to represent maintenance instructions. In particular, in this work we identified the most frequent maintenance actions used in manuals, and converted them into graphical symbols. Then, we made an elicitation of the symbols designed and created different candidate vocabularies of symbols basing on the criteria found in literature of guessability and homogeneity. Moreover, the vocabularies had to respect two constraints: conflict set and reversibility. Finally, we identified the best of symbols and integrated this one in a real AR application for remote maintenance.

Keywords: Augmented Reality | Industry 4.0 | Maintenance

Abstract: In a context more and more oriented towards customized medical solutions, we propose a mechanobiology-driven algorithm to determine the optimal geometry of scaffolds for bone regeneration that is the most suited to specific boundary and loading conditions. In spite of the huge number of articles investigating different unit cells for porous biomaterials, no studies are reported in the literature that optimize the geometric parameters of such unit cells based on mechanobiological criteria. Parametric finite element models of scaffolds with rhombicuboctahedron unit cell were developed and incorporated into an optimization algorithm that combines them with a computational mechanobiological model. The algorithm perturbs iteratively the geometry of the unit cell until the best scaffold geometry is identified, i.e. the geometry that allows to maximize the formation of bone. Performances of scaffolds with rhombicuboctahedron unit cell were compared with those of other scaffolds with hexahedron unit cells. We found that scaffolds with rhombicuboctahedron unit cell are particularly suited for supporting medium-low loads, while, for higher loads, scaffolds with hexahedron unit cells are preferable. The proposed algorithm can guide the orthopaedic/surgeon in the choice of the best scaffold to be implanted in a patient-specific anatomic region.

Keywords: Computational mechanobiology | Morphology optimization | Rhombicuboctahedron | Scaffold unit cell

Abstract: Design of scaffolds for tissue engineering entails multi-disciplinary and multi-scale aspects. Since in vivo analysis of the tissue regeneration process is quite difficult in terms of selecting experimental protocols and requires considerable amount of time, a variety of numerical models have been developed to simulate mechanisms of tissue differentiation. The tremendous enhancement in computing power led researchers to develop more and more sophisticated models mostly based on finite element techniques and mechano-regulation computational models. In this article, we present an algorithm that combines the finite element model of an open-porous scaffold, a numerical optimization routine and a mechanobiological model. This algorithm has been utilized to determine both, the best scaffold geometry and the best load value (to apply on the scaffold) that allow the bone formation to be maximized.

Keywords: Bone tissue scaffold | Computational mechanobiology | Geometry optimization | Scaffold micro-architecture

Abstract: Background: New sources of stem cells in adult organisms are constantly emerging. Postnatal Mesenchymal Stem Cells (MSCs), are the most promising support to perform an effective regenerative medicine: such cells have the ability to differentiate into several lineages, such as osteoblasts and chondroblasts, providing novel strategies to improve different complex treatments, during bone regeneration. 3D-printed biomaterials can be designed with geometry aimed to induce stem cells to differentiate towards specific lineage. Objective: The interaction between stem cells easy to isolate and engineered 3D-printed scaffolds can translate the tissue bio-engineering into bone regenerative surgery. For those reasons, to better identify the complexity represented by the activities and responses of MSCs requires the advance of new target therapies which are not current in endocrine, metabolic and immune disorders and yet to be developed. Method: This topical review briefly focuses on the new approaches of translational medicine with the use of MSCs and scaffolds engineered with the aid of 3D-printing technology, highlights the osteogenic functions and addresses their applications across the breadth of regenerative medicine. Results: The application of bone constructs consisting of the engineered scaffold and MSCs as well as the aspects related to the optimal scaffold geometry that favours the best MSCs differentiation and the improvement of concepts as “sensing surface” were also discussed. Conclusion: Regenerative surgery is largely growing in the field of translational medicine. The use of new sources of MSCs and the improvement of new concepts of bio-engineered scaffolds will certainly be the next step of customized medicine.

Keywords: 3D-printed scaffolds | Customized medicine | Mesenchymal stem cells | Regenerative medicine | Tissue engineering | Translational medicine

Abstract: Thanks to the recent advances of three-dimensional printing technologies the design and the fabrication of a large variety of scaffold geometries was made possible. The surgeon has the availability of a wide number of scaffold micro-architectures thus needing adequate guidelines for the choice of the best one to be implanted in a patient-specific anatomic region. We propose a mechanobiology-based optimization algorithm capable of determining, for bone tissue scaffolds with an assigned geometry, the optimal value Lopt of the compression load to which they should be subjected, i.e. the load value for which the formation of the largest amounts of bone is favoured and hence the successful outcome of the scaffold implantation procedure is guaranteed. Scaffolds based on hexahedron unit cells were investigated including pores differently dimensioned and with different shapes such as elliptic or rectangular. The algorithm predicted decreasing values of the optimal load for scaffolds with pores with increasing dimensions. The optimal values predicted for the scaffolds with elliptic pores were found higher than those with rectangular ones. The proposed algorithm can be utilized to properly guide the surgeon in the choice of the best scaffold type/geometry that better satisfies the specific patient requirements.

Keywords: Computational Mechanobiology | Hexahedron Unit Cell | Numerical Optimization Algorithms | Printing of Biomaterials | Scaffolds for Bone Tissue Engineering

Abstract: Augmented reality (AR) is a key technology for the development of smart manufacturing. One of the main advantages of AR is that it can help workers to accomplish several tasks, making it possible the shift from mass production to mass customization. However, it is still not clear how these promises can be fulfilled in an industrial scenario. In particular, the question about which display solutions fit better the industrial constraints remains open. Based on the literature overview, laboratory experiments, and feedbacks from industrial companies, we supported the use of spatial augmented reality (SAR), designing a prototype intended to be used for manual working stations of the future smart factories. This work presents the evaluation of the effectiveness of conveying technical instructions with this SAR prototype as compared to paper manual. We run a within-subjects experiment with 16 participants to measure user task performance (completion times and error rates) and to collect subjective evaluation. We projected technical information on a motorbike engine during a seven-task maintenance procedure. Our results proved that SAR technology improves the operators’ performance with respect to a paper manual and that users well accept it. We found that SAR is more effective for difficult tasks than for simple ones and that the main advantage of SAR is related more to the reduction of error rates than to completion times. These results confirm the goodness of our design choices; then our prototype can be a valid candidate solution for a smart manufacturing application.

Keywords: Assembly | Industry 4.0 | Maintenance | Projection | Spatial augmented reality | Technical instructions

Abstract: This article explores what it takes to make interactive computer graphics and VR attractive as a promotional vehicle, from the points of view of tourism agencies and the tourists themselves. The authors exploited current VR and human-machine interface (HMI) technologies to develop an interactive, innovative, and attractive user experience called the Multisensory Apulia Touristic Experience (MATE). The MATE system implements a natural gesture-based interface and multisensory stimuli, including visuals, audio, smells, and climate effects.

Keywords: computer graphics | gesture controls | human-machine interface | multisensory virtual environment | natural user interfaces

Abstract: The evaluation of the exposure to risk factors in workplaces and their subsequent redesign represent one of the practices to lessen the frequency of work-related musculoskeletal disorders. In this paper we present K2RULA, a semi-automatic RULA evaluation software based on the Microsoft Kinect v2 depth camera, aimed at detecting awkward postures in real time, but also in off-line analysis. We validated our tool with two experiments. In the first one, we compared the K2RULA grand-scores with those obtained with a reference optical motion capture system and we found a statistical perfect match according to the Landis and Koch scale (proportion agreement index = 0.97, k = 0.87). In the second experiment, we evaluated the agreement of the grand-scores returned by the proposed application with those obtained by a RULA expert rater, finding again a statistical perfect match (proportion agreement index = 0.96, k = 0.84), whereas a commercial software based on Kinect v1 sensor showed a lower agreement (proportion agreement index = 0.82, k = 0.34).

Keywords: Ergonomics | Kinect v2 | RULA

Abstract: Text legibility in augmented reality with optical see-through displays can be challenging due to the interaction with the texture on the background. Literature presents several approaches to predict legibility of text superimposed over a specific image, but their validation with an AR display and with images taken from the industrial domain is scarce. In this work, we propose novel indices extracted from the background images, displayed on an LCD screen, and we compare them with those proposed in literature designing a specific user test. We collected the legibility user ratings by displaying white text over 13 industrial background images to 19 subjects using an optical see-through head-worn display. We found that most of the proposed indices have a significant correlation with user ratings. The main result of this work is that some of the novel indices proposed had a better correlation than those used before in the literature to predict legibility. Our results prove that industrial AR developers can effectively predict text legibility by simply running image analysis on the background image.

Abstract: Characterisation of the mechanical behaviour of cancer cells is an issue of crucial importance as specific cell mechanical properties have been measured and utilized as possible biomarkers of cancer progression. Atomic force microscopy certainly occupies a prominent place in the field of the mechanical characterisation devices. We developed a hybrid approach to characterise different cell lines (SW620 and SW480) of the human colon carcinoma submitted to nanoindentation measurements. An ad hoc algorithm was written that compares the force-indentation curves experimentally retrieved with those predicted by a finite element model that simulates the nanoindentation process and reproduces the cell geometry and the surface roughness. The algorithm perturbs iteratively the values of the cell mechanical properties implemented in the finite element model until the difference between the experimental and numerical force-indentation curves reaches the minimum value. The occurrence of this indicates that the implemented material properties are very close to the real ones. Different hyperelastic constitutive models, such as Arruda-Boyce, Mooney-Rivlin and Neo-Hookean were utilized to describe the structural behaviour of indented cells. The algorithm was capable of separating, for all the cell lines investigated, the mechanical properties of cell cortex and cytoskeleton. Material properties determined via the algorithm were different with respect to those obtained with the Hertzian contact theory. This demonstrates that factors such as: the cell geometry/anatomy and the hyperelastic constitutive behaviour, which are not contemplated in the Hertz's theory hypotheses, do affect the nanoindentation measurements. The proposed approach represents a powerful tool that, only on the basis of nanoindentation measurements, is capable of characterising material at the subcellular level.

Keywords: cell cortex | cell geometry | colon carcinoma | cytoskeleton | finite element method | nanoindentation | rough surface

Abstract: This paper presents an example of applicability of the STEP standard in a design process of a new specific sub-assembly product in the heavy machinery industry in Serbia. We tested the interoperability of the STEP standard in several CAD systems and their compatibility and quality of conversion process. Results obtained in performed experiments demonstrate that the STEP standard offers simplified data exchange between heterogeneous CAD systems and serves not only as a tool for integration and exchange the data of products and processes, but subsequently supports the integration of companies by increasing the global competitiveness, more efficient archiving, evolving and reusing the data in a solving complex entrepreneurial and production problems worldwide.

Keywords: CAD data exchange | CAD tools | Interoperability | STEP

Abstract: Due to the Industry 4.0 initiative, Augmented Reality (AR) has started to be considered one of the most interesting technologies companies should invest in, especially to improve their maintenance services. Several technological limitations have prevented AR to become an effective industrial tool in the past. Now some of them have been overcome, some others not yet by off-the-shelf technologies. In this paper, we present a solution for remote maintenance based on off-the-shelf mobile and AR technologies. The architecture of the application allows us to remotely connect a skilled operator in a control room with an unskilled one located where the maintenance task has to be performed. This application, which has been initially described in a previous work, has been improved on the basis of feedback received by industrial partners. We describe the important features we have added and the rationale behind them to make the remote communication more effective.

Keywords: Augmented Reality | Industry 4.0 | Remote Maintenance

Abstract: In this work, we proposed a method to reduce text in technical documentation, aiming at Augmented Reality manuals, where text must be reduced as much as possible. In fact, most of technical information is conveyed through other means such as CAD models, graphic signs, images, etc. The method classifies technical instructions into two categories: instructions that can be presented with graphic symbols and instructions that should be presented with text. It is based on the analysis of the action verbs used in the instruction, and makes use of ASD Simplified Technical English (STE) for remaining text instructions and let them easier to translate into other languages.

Keywords: Augmented Reality | Graphic symbols | Industry 4.0 | Simplified Technical English | Technical Documentation | Text reduction | Visual

Abstract: Blepharospasm is characterized by bilateral, synchronous, and symmetric involuntary orbicularis oculi muscle spasms leading to partial/total eyelid closure. We proposed a comprehensive method for assessing the severity of blepharospasm cases, based on expert observation of fixed-length video recordings and natural feature detection algorithms. The developed software detects involuntary spasms and blinks in order to evaluate BSP severity. In this work we have considered a new BSP severity scale to realize an objective evaluation of BSP severity.

Abstract: Endocanalar posts are necessary to build up and retain coronal restorations but they do not reinforce dental roots. It was observed that the dislodgement of post-retained restorations commonly occurs after several years of function and long-term retention may be influenced by various factors such as temperature changes. Temperature changes, in fact, produce micrometric deformations of post and surrounding tissues/materials that may generate high stress concentrations at the interface thus leading to failure. In this study we present an optical system based on the projection moiré technique that has been utilized to monitor the displacement field of endocanalar glass-fibre posts subjected to temperature changes. Measurements were performed on forty samples and the average displacement values registered at the apical and middle region were determined for six different temperature levels. A total of 480 displacement measurements was hence performed. The values of the standard deviation computed for each of the tested temperatures over the forty samples appear reasonably small which proves the robustness and the reliability of the proposed optical technique. The possible implications for the use of the system in the applicative context were discussed.

Keywords: Dental materials | Endocanalar post | Projection moiré | Thermal deformation | Thermal stress

Abstract: We present a novel interaction method for augmented industrial maintenance based on a "magic mirror" interface and virtual motion buttons. The system includes a video camera for object tracking, a video\depth camera for capturing user gestures, a projector for displaying technical instruction to the operator and a LCD monitor providing feedback of the virtual buttons. The operator can trigger maintenance commands by directional swift of the hands in regions sensitive to motion speed and direction. The main advantage of the presented interface is that it can work in realistic industrial conditions: (i) operators wearing gloves, (ii) operators handling tools, (iii) presence of moving machinery and personnel in the background. We measured the performances of the system with a laboratory test and we proved the feasibility with an automotive inspection test case. We calculated an average interaction time below 2 seconds and an error rate lower than 5%. However, we found some performances limitations if the operator is handling tools.

Keywords: Augmented reality | Computer assisted maintenance | Human computer interfaces | Motion buttons

Abstract: Recent Face Analysis advances have focused the attention on studying and formalizing 3D facial shape. Landmarks, i.e. typical points of the face, are perfectly suited to the purpose, as their position on visage shape allows to build up a map of each human being’s appearance. This turns to be extremely useful for a large variety of fields and related applications. In particular, the forensic context is taken into consideration in this study. This work is intended as a survey of current research advances in forensic science involving 3D facial landmarks. In particular, by selecting recent scientific contributions in this field, a literature review is proposed for in-depth analyzing which landmarks are adopted, and how, in this discipline. The main outcome concerns the identification of a leading research branch, which is landmark-based facial reconstruction from skull. The choice of selecting 3D contributions is driven by the idea that the most innovative Face Analysis research trends work on three-dimensional data, such as depth maps and meshes, with three-dimensional software and tools. The third dimension improves the accurateness and is robust to colour and lightning variations.

Keywords: 3D face | Fiducial point | Forensic | Landmarks | Reconstruction

Abstract: We present the design and a prototype of a projective AR workbench for an effective use of the AR in industrial applications, in particular for Manual Working Stations. The proposed solution consists of an aluminum structure that holds a projector and a camera that is intended to be mounted on manual working stations. The camera, using a tracking algorithm, computes in real time the position and orientation of the object while the projector displays the information always in the desired position. We also designed and implemented the data structure of a database for the managing of AR instructions, and we were able to access this information interactively from our application.

Abstract: We present a prototype system composed practically of an IR camera and a video projector with the purpose to create a device that projects the thermal map directly on the observed surface. The novelty of this work lies on the building of a portable tool, the development of software and the proposing of a calibration procedure to be used in industrial and construction sites from thermal inspectors.

Abstract: In this paper, we propose a forearm rehabilitation system based on a serious game in Augmented Reality (AR). We designed and developed a simplified AR arcade brick breaking game to induce rehabilitation of the forearm muscles. We record the electromyographic signals using a low cost device to evaluate the applied force. We collected and analysed data in order to find a relationship between the applied force and the difficulty of the game. This research focuses on the dehospitalization of subjects in the middle or final stages of their rehabilitation where the new technologies, like Virtual and Augmented Reality, may improve the experience of repetitive exercises. The results achieved prove that the force applied by the user to hit the virtual sphere with real cardboard cube is related to sphere speed. In a rehabilitation scenario the results could be used to evaluate the improvements analysing the performance history.

Keywords: Brick serious games | Rehabilitation | Virtual and Augmented Reality

Abstract: Functionally Graded Scaffolds (FGSs) are porous biomaterials where porosity changes in space with a specific gradient. In spite of their wide use in bone tissue engineering, possible models that relate the scaffold gradient to the mechanical and biological requirements for the regeneration of the bony tissue are currently missing. In this study we attempt to bridge the gap by developing a mechanobiology-based optimization algorithm aimed to determine the optimal graded porosity distribution in FGSs. The algorithm combines the parametric finite element model of a FGS, a computational mechano-regulation model and a numerical optimization routine. For assigned boundary and loading conditions, the algorithm builds iteratively different scaffold geometry configurations with different porosity distributions until the best microstructure geometry is reached, i.e. the geometry that allows the amount of bone formation to be maximized. We tested different porosity distribution laws, loading conditions and scaffold Young's modulus values. For each combination of these variables, the explicit equation of the porosity distribution law-i.e the law that describes the pore dimensions in function of the spatial coordinates-was determined that allows the highest amounts of bone to be generated. The results show that the loading conditions affect significantly the optimal porosity distribution. For a pure compression loading, it was found that the pore dimensions are almost constant throughout the entire scaffold and using a FGS allows the formation of amounts of bone slightly larger than those obtainable with a homogeneous porosity scaffold. For a pure shear loading, instead, FGSs allow to significantly increase the bone formation compared to a homogeneous porosity scaffolds. Although experimental data is still necessary to properly relate the mechanical/biological environment to the scaffold microstructure, this model represents an important step towards optimizing geometry of functionally graded scaffolds based on mechanobiological criteria.

Abstract: Complexity of scaffold geometries and biological mechanisms involved in the bone generation process make the design of scaffolds a quite challenging task. The most common approaches utilized in bone tissue engineering require costly protocols and time-consuming experiments. In this study we present an algorithm that, combining parametric finite element models of scaffolds with numerical optimization methods and a computational mechano-regulation model, is able to predict the optimal scaffold microstructure. The scaffold geometrical parameters are perturbed until the best geometry that allows the largest amounts of bone to be generated, is reached. We study the effects of the following factors: (1) the shape of the pores; (2) their spatial distribution; (3) the number of pores per unit area. The optimal dimensions of the pores have been determined for different values of scaffold Young’s modulus and compression loading acting on the scaffold upper surface. Pores with rectangular section were predicted to lead to the formation of larger amounts of bone compared to square section pores; similarly, elliptic pores were predicted to allow the generation of greater amounts of bone compared to circular pores. The number of pores per unit area appears to have rather negligible effects on the bone regeneration process. Finally, the algorithm predicts that for increasing loads, increasing values of the scaffold Young’s modulus are preferable. The results shown in the article represent a proof-of-principle demonstration of the possibility to optimize the scaffold microstructure geometry based on mechanobiological criteria.

Keywords: Mechano-regulation algorithm | Mechanobiology | Numerical optimization | Scaffold microstructure

Abstract: This paper presents a novel application of natural interaction techniques for technical documentation navigation in augmented reality maintenance. The objective is to provide technical information where and when needed in order to reduce the time spent in retrieving procedural data from manuals. The system integrates a video and depth camera for user gesture acquisition, a webcam for marker-based tracking and a see through head mounted display for digital information overlay. We designed a novel hand free gesture-based interface to access technical documentation while performing maintenance tasks. We implemented a specific flexible system to prototype natural interfaces using UML configurable state machines. It supports 2D and 3D content navigation, CAD assembly explosion, real time 3D sectioning and operation browsing. We differentiate the interaction metaphors for 2D documents and 3D CAD models in order to be intuitive and easy to learn. A case study and a user test demonstrated the feasibility and the good acceptance of the presented gesture interface.

Keywords: 3D hand gestures | Augmented reality | Digital technical documentation | Industrial maintenance | Natural interface

Abstract: A correct recognition of nonverbal expressions is currently one of the most important challenges of research in the field of human computer interaction. The ability to recognize human actions could change the way to interact with machines in several environments and contexts, or even the way to live. In this paper, we describe the advances of a previous study finalized to design, implement and validate an innovative recognition system already developed by some of the authors. It was aimed at recognizing two opposite emotional conditions (resonance and dissonance) of a candidate to a job position interacting with the recruiter during a job interview. Results in terms of the accuracy, resonance rate, and dissonance rate of the three new optimized neural networkbased (NN) classifiers are discussed. Comparison with previous results of three NN classifiers is also presented based on three single domains: facial, vocal and gestural.

Keywords: Facial/vocal/gestural features | Job interview | Neural networks and support vector machines | Nonverbal emotional recognition

Abstract: Augmented Reality is a promising technology for the product lifecycle development, but it is still not established in industrial facilities. The most relevant issues to be addressed relate to the ergonomics: avoid the discomfort of Head-Worn Displays, allow the operators to have free hands and improve data visualization. In this work we study the possibility to use projection-based Augmented Reality (projected AR), as optimal solution for technical visualization on industrial workbenches. In particular, text legibility in projected AR is difficult to optimize since it is affected by many parameters: environment conditions, text style, material and shape of the target surface. This problem is poorly addressed in literature and in the specific industrial field. We analyze the legibility of a set of colors prescribed by international standards for the industrial environments, on six widely used industrial workbenches surfaces. We compared the performance of 14 subjects using projected AR, with that using a traditional LCD monitor. We collected about 2500 measurements (times and errors) through the use of a test application, followed by qualitative interviews. The results showed that, as regards legibility, projected AR can be used in place of traditional monitors in most of the cases. Another not trivial finding is that the influence on legibility of surface irregularities (e.g., grooves, prominences) is more important than that of surface texturization. A possible limitation for the use of projected AR is given by the blue color, whose performance turned out to be lower than that of other colors with every workbench surface.

Keywords: Industrial applications | Spatial Augmented Reality | Text legibility | Visualization

Abstract: Text readability with augmented reality head-worn displays is critical and at present time, there are no standard guidelines to follow. The readability depends mainly on background lighting, display technology (i.e., OST: optical see-through or VST: video see-through), and text style (e.g., plain text, outline or billboard). In this work, we addressed the readability limits for industrial activities. We experimented the effects of two background illuminances levels (1,000 lx for very fine basic industrial tasks and 4,000 lx for fine machining), two commercially available head-worn display technologies, variable outline widths and contrast polarity of text. We analyzed the performance of 12 subjects by collecting about 3,400 measurements using a specific test application and followed by qualitative interviews. With high illuminances, VST performed better than OST, regardless of contrast polarity and outline width. We found that negative contrast polarity is preferable with VST, and that just a minimum outline (1 px) around black text is optimal. On the contrary, positive contrast polarity should be used with OST and outline is not effective. Therefore, we evaluated the usage limits of the OST by sampling its contrast sensitivity function.

Keywords: Augmented reality | Contrast sensitivity function | Industrial lighting | Optical see-through | Video see-through

Abstract: In the Industrie 4.0 vision, the creation of leading-edge options for interaction between people and technology occupies a key role. In this context, augmented reality (AR) is one of the most suitable solutions. However, it is still not ready to be effectively used in industry. A crucial problem is the legibility of text seen through AR head-worn displays (HWDs). AR interface designers have no standard guidelines to follow, especially for these devices. Literature and anecdotal evidence suggest that legibility depends mainly on background, display technology (that is, see-through optical or video HWDs), and text style (for example, plain text, outline, or billboard). Furthermore, there are constraints to consider in industrial environments, such as standard color-coding practices and workplace lighting. The authors examine aspects affecting text legibility with an emphasis on deriving guidelines to support AR interface designers. Their results suggest that enhancing text contrast via software, along with using the outline or billboard style, is an effective practice to improve legibility in many situations. If one text style is needed for both types of HWD, their results suggest that colored billboards (with neutral white text) are effective. When color coding is not mandatory, white text and blue billboard are more effective than other styles tested.

Keywords: augmented reality | computer graphics | head-worn displays | human-computer interface | Industrie 4.0 | mixed reality | style guides | usability engineering | vision I/O

Abstract: ABSTRACT: The paper describes an interactive Finite Elements Analysis (FEA) tool that aims to improve the learning of mechanical behavior of materials in industrial engineering schools. We implemented a “user in the loop” approach where students can explore the mechanical behavior of virtual specimens selected from a library of standard elements (cantilever beam, IPE beams etc.). The users can apply forces or displacements interactively by mouse or haptic device, and visualize and “feel” the structures stress configurations. We extended our previous work and compared this novel approach with respect to traditional FEA learning techniques. A test with twenty engineering students showed that learners following the interactive approach are faster in completing the given assignment showing a reduced error rate.

Keywords: engineering education | haptics | real-time finite element analysis | virtual reality

Abstract: We present an empirical study that evaluates the effectiveness of technical maintenance assisted with interactive augmented reality instructions. Our approach consists in an augmented visualization on a large screen and a combination of multiple fixed and mobile cameras. We used commercially available solutions. In our test, 14 participants completed a set of 4 maintenance tasks based on manual inspections of a motorbike engine. Tool selection, removal of bolts, and part dis\assembly, are supported by visual labels, 3D virtual models and 3D animations. All participants executed similar operations in two modalities: paper manuals and augmented instructions. Statistical analyses proved that augmented instructions reduced significantly participants' overall execution time and error rate. © 2013 Elsevier B.V. All rights reserved.

Keywords: Augmented reality | Computer aided task guidance | Large screen instruction | Maintenance

Abstract: Product maintenance is a service offered to customers which represents an interesting business for companies. Their interest is both providing a good service in terms of quality and at the same time cutting operational costs. In this view companies are seeking tools that enable them to reach both goals, among those offered by the rapidly evolving ICT sector. The paper describes an application based on augmented reality and mobile technologies aiming to support remote maintenance operations, and improve maintenance services that companies offer to their customers. The paper describes the main idea at the basis of the application, the requirements as well as its implementation. Finally a case study is presented.

Abstract: Augmented reality (AR) applications rely on robust and efficient methods for tracking. Tracking methods use a computer-internal representation of the object to track, which can be either sparse or dense representations. Sparse representations use only a limited set of feature points to represent an object to track, whereas dense representations almost mimic the shape of an object. While algorithms performed on sparse representations are faster, dense representations can distinguish multiple objects. The research presented in this paper investigates the feasibility of a dense tracking method for rigid object tracking, which incorporates the both object identification and object tracking steps. We adopted a tracking method that has been developed for the Microsoft Kinect to support single object tracking. The paper describes this method and presents the results. We also compared two different methods for mesh reconstruction in this algorithm. Since meshes are more informative when identifying a rigid object, this comparison indicates which algorithm shows the best performance for this task and guides our future research efforts.

Abstract: Efficient text visualization in head-worn augmented reality (AR) displays is critical because it is sensitive to display technology, text style and color, ambient illumination and so on. The main problem for the developer is to know the optimal text style for the specific display and for applications where color coding must be strictly followed because it is regulated by laws or internal practices. In this work, we experimented the effects on readability of two head-worn devices (optical and video see-through), two backgrounds (light and dark), five colors (white, black, red, green, and blue), and two text styles (plain text and billboarded text). Font type and size were kept constant. We measured the performance of 15 subjects by collecting about 5,000 measurements using a specific test application and followed by qualitative interviews. Readability turned out to be quicker on the optical see-through device. For the video see-through device, background affects readability only in case of text without billboard. Finally, our tests suggest that a good combination for indoor augmented reality applications, regardless of device and background, could be white text and blue billboard, while a mandatory color should be displayed as billboard with a white text message. © 1995-2012 IEEE.

Keywords: Augmented reality | optical see-through | style guides | video see-through | vision I/O

Abstract: The interaction metaphor, based on mouse, monitor and keyboard, presents evident limits in the engineering design review activities, when real and virtual models must be explored and compared, and also in "outside-the-office" environments, where the desk is not available. The presented research aims to explore a new generation of gesture-based interfaces, called "natural interfaces", which promise an intuitive control using free hands and without the desk support. We present a novel natural design review workspace which acquires user motion using a combination of video and depth cameras and visualizes the CAD models using monitor-based augmented reality. We implemented a bimanual egocentric pointer paradigm by a virtual active surface in front of the user. We used a XML configurable approach to explore bimanual gesture commands to browse, select, dis/assembly and explode 3D complex models imported in standard STEP format. Our experiments demonstrated that the virtual active surface is able to effectively trigger a set of CAD specific commands and to improve technical navigation in non-desktop environments: e.g. shop floor maintenance, on site quality control, etc. We evaluated the feasibility and robustness of the interface and reported a high degree of acceptance from the users who preferred the presented interface to a unconstrained 3D manipulation. © 2012 Springer-Verlag France.

Keywords: 3D manipulation | Augmented reality | CAD | Depth camera | Human computer interfaces | Natural interfaces

Abstract: We developed a wearable device to improve lower limb sport training. The presented system consists of a pair of spandex shorts which embed a processor unit, 2 accelerometers and 2 vibro motors. The accelerometers are located in proximity to the knees and measure tri-axial accelerations. We present a novel method to compute and correct asymmetry of lower limbs during training. The user performs an initial calibration phase which sets the accelerometer reference frames. While running, the system continuously refines the calibration using principal component analysis to take in account occasional shorts assessments. The system activates a corrective vibro feedback on the specific leg according to an asymmetry metric based on: (i) foot ground impact, (ii) phase error between legs, (iii) transversal knee movements. User tests demonstrated that the device is ergonomic to wear, easy to use and the corrective vibro feedback is appreciated during the training.

Keywords: Asymmetry correction | Lower limb rehabilitation | Sport training | Vibro feedback | Wearable training device

Abstract: The application of augmented reality in industrial environments requires an effective visualization of text on a see-through head-mounted display (HMD). The main contribution of this work is an empirical study of text styles as viewed through a monocular optical see-through display on three real workshop backgrounds, examining four colors and four different text styles. We ran 2,520 test trials with 14 participants using a mixed design and evaluated completion time and error rates. We found that both presentation mode and background influence the readability of text, but there is no interaction effect between these two variables. Another interesting aspect is that the presentation mode differentially influences completion time and error rate. The present study allows us to draw some guidelines for an effective use of AR text visualization in industrial environments. We suggest maximum contrast when reading time is important, and the use of colors to reduce errors. We also recommend a colored billboard with transparent text where colors have a specific meaning. © 2013 by the Massachusetts Institute of Technology.

Abstract: The paper describes a novel application of real-time finite element analysis controlled by a haptic device. The user can impose displacement constraints to a virtual structure using a probe and sense in real-time the response in terms of forces on her/his hand. In addition, conventional color map results are visualized on a desktop monitor. The application has been developed with the aim of simplifying the teaching of the mechanical behavior of materials in engineering schools by transforming the learning phase into an enactive process. A set of examples commonly used in the mechanical engineering courses have been implemented and tested. The paper describes and discusses the system implementation, the potentialities and the issues of such approach. Copyright © 2013 by ASME.

Abstract: Engineering 3D models become complex that paper drawings representation and monitor/mouse navigation on a computer-aided design (CAD) system is difficult and also frustrating. We present a novel interface paradigm for natural interactive visualization. It incorporates augmented reality enhanced engineering drawings and natural and tangible interfaces. We embedded ID markers on technical drawings to provide CAD data retrieval and tangible navigation. A user gets access to the CAD navigation functions using the drawing itself as a tangible device. In addition, CAD functions are triggered with gestures recognized by a video camera. We performed a pilot test assessment with industrial engineers. The results demonstrate the feasibility and the effectiveness of these techniques. © 2012 American Society of Mechanical Engineers.

Abstract: We present a novel approach to the early diagnosis of lung tumors that considers new malignancy indexes by using a metaball-based representation of this neoplasia. Starting from CT data we extract the suspected tumors represented as approximating metaballs and calculate malignancy indexes based on precise volume and surface irregularity evaluation. The mentioned approximation is performed resolving a constraint problem using a genetic algorithm whose objective function is a mathematical representation of the metaball. Compared to existing art, the metaball approximation provides a consistent reference surface for the evaluation of novel diagnosis parameters borrowed from engineering surface analysis. We have implemented the method in a demonstrator software and analyzed three different test cases. Copyright 2012 ACM.

Keywords: Biomedical computation | Genetic algorithm constrained optimization problem | GENOCOP III | Lung Tumor diagnosis | Surface analysis

Abstract: This work presents a novel Augmented Realty (AR) application to superimpose interactive Product Manufacturing Information (PMI) onto paper technical drawings. We augment drawings with contextual data and use a novel tangible interface to access the data in a natural way. We present an optimized PMI data visualization algorithm for CAD models in order to avoid model and annotation cluttering. Our algorithm ranks the model faces with technical annotations according to angle, distance, occlusion and area. The number of annotations visualized on 3D model is chosen following the cognitive perception theory to avoid information overload. We also extended the navigation metaphor adding the concept of tangible model navigation and flipping using the duplex drawing. As case studies we used annotated models from ASME standards. By using PC hardware and common paper drawings, this approach can be integrated at low-cost in existing industrial processes. Copyright © 2011 by ASME.

Keywords: Augmented reality | PMI annotations | Technical drawing

Abstract: We present a novel self-calibrating wearable device to improve running training by active vibro feedback. The system consists of a pair of spandex shorts embedding: a processor unit, 2 three-axial accelerometers, 2 vibro motors, a SD card reader\writer module and a real time clock. Two supplementary wireless accelerometers are located on the shoes. We present an algorithm to compute gait asymmetry from the four sensors data. The main novelty is the auto calibration algorithm which uses principal component analysis on each sensor based on kinematic assumptions. The system provides two important advantages: data logging and real time active correction. The active correction is performed sending signals to the user in real time via vibrations cells (rumble feedback). The vibration signals are sent to the specific leg and its intensity is proportional to the entity of required correction. This training system for running can be very useful to athletes and to sport medicine in order to improve speed, posture, fatigue and reduce joints osteoarthrotic problems.

Keywords: Active posture correction | Running training | Vibro feedback | Wearable wireless device

Abstract: The main objective of this works is to develop a wearable device to improve sport training in lower limb. The system consists of a pair of spandex shorts which embed a processor unit, 2 accelerometers, 2 vibro motors, a SD card reader\writer module and a real time clock. The accelerometers are located in proximity to the knees and are used to measure in real time the tri-axial accelerations for each leg. We present a novel algorithm to compute asymmetry from the 3 axial sensor data. We propose two applications of the system: for real time active correction and for data logging. In the correction mode, adjustment signal are sent to the user during the training by vibrations. The vibration signal is sent to the specific leg and its intensity is related to the entity of required correction. The second application of the system is as datalogger. The device stores all the training data in a SD card. Those log files can be processed using a dedicated application on a PC. This information can be very useful for long term analysis. This novel approach to sport training is very useful to athletes and sport medicine doctor in order to improve posture, efficiency and performance, but it can be also useful in other medical appliances such as rehabilitation. © 2011 IEEE.

Keywords: posture correction | sport training | vibro feedback | wearable

Abstract: We present a novel framework for computer aided measurements which supports physicians during 3D virtual colonoscopy. We propose a four steps methodology: (i) segment colon regions, (ii) search for colorectal polyps by means of a supervised neural network architecture, (iii) 3D reconstruction of polyp geometry using a synthetic model and (iv) qualitative and quantitative geometrical analysis. Doctor can graphically visualize and inspect the surface and search for irregularities. This qualitative visual support is extended with mathematical tools which computes diagnostic indicators. The proposed tool was tested with two different data sets of polyps. The proposed approach can be an effective diagnostic tool to evaluate the degree of malignancy of the cancer. Due to its generality, the presented framework can be easily extended to search for other types of cancers. © 2011 IEEE.

Keywords: 2D segmentation | 3D rendering and 2D and 3D measurements | neural networks | polyps | Virtual Conolonoscopy

Abstract: Style sketches are an essential tool for the expression and the definition of the shape of industrial products. We present a novel wavelet approach for sketch segmentation and editing expressly addressed to the designer needs. Starting from a 2D curve drawn by a user with a graphics tablet, our algorithm converts it in a B-spline representation, detects the style features, allows interactive smoothing and continuous local and global editing. The novelty compared to the existing literature is the combination of: (i) unified wavelet approach to segmentation, smoothing and editing, (ii) support for endpoint C0 and C1 continuity constraints and (iii) implementation with an interactive pen-tablet interface. Our approach requires low memory footprints with time complexity linear in the number of control points. We validated the algorithm with synthetic and practical tests. © 2010 World Scientific Publishing Company.

Keywords: 2D interactive sketch | multi-level segmentation | multiresolution editing

Abstract: In this work we integrate augmented reality technology in a product development process using real technical drawings as a tangible interface for design review. We present an original collaborative framework for Augmented Design Review Over Network (ADRON). It provides the following features: augmented technical drawings, interactive FEM simulation, multimodal annotation and chat tools, web content integration and collaborative client/server architecture. Our framework is intended to use common hardware instead of expensive and complex virtual or augmented facilities. We designed the interface specifically for users with little or no augmented reality expertise proposing tangible interfaces for data review and visual editing for all the functions and configurations. Two case studies are presented and discussed: a real-time "touch and see" stress/strain simulation and a collaborative distributed design review session of an industrial component. © 2008 Elsevier Ltd. All rights reserved.

Keywords: 3D model annotation | Augmented reality | Collaborative design review | FEM data visualization

Abstract: Part modelling in a CAD environment requires a bi-manual 3D input interface to fully exploit its potentialities. In this research we provide extensive user tests on bi-manual modelling using different devices to control 3D model's rotation. Our results suggest that a simple trackball device is effective when the user task is mostly limited to rotation control (i.e. when modelling parts in a CAD environment). In our tests, performances are even better than those achieved with a specifically designed device. Since the task of rotating a CAD part often shows the need of flipping the controlled object, we introduce a non linear transfer function which combines the precision of a zero order control mode with the ability to recognise fast movements. This new modality shows a significant improvement in the user's performances and candidates itself for integration in next generation CAD interfaces. © 2008 Elsevier Ltd. All rights reserved.

Keywords: 3D input | Bimanual interaction | Human computer interface | Part modelling | VR CAD

Abstract: This paper presents a novel 'touch and see' approach for interactive leaching of dynamic stress/strain distribution in engineering education. Our Augmented Reality application visualizes Finite Element Method (FEM) results overlaid over the real model. The user can interactively change the boundary conditions of the simulation and then evaluate the stress distribution in real time. Marker based video tracking is used to measure displacements while COMSOL Multiphysics solves the structural FEM analysis. A cantilever test case has been implemented and evaluated We describe the optimization solutions needed to achieve real-time simulation and precise and stable tracking. The presented system demonstrates significant educational benefits making the student's experience more attractive and effective. © 2009 TEMPUS Publications.

Keywords: Active learning | Augmented Reality | FEM | Tangible interfaces

Abstract: We present a novel approach, called tangible digital master (TaDiMa), based on a flexible access to Product Lifecycle Management (PLM) database using a tangible/graphical user interface and augmented reality. We developed and tested a technical drawing template with automatically embedded markers for augmentation. We embedded the Mozilla FireFox engine into our annotation system for the integration of web 2.0 applications in the AR environment. We also extended the concept of web feed to PLM for notification of technical contents. We implemented a dynamic labelling management with view-driven filtering and placement. We also present a tangible management for layers visualization and users access by marked tokens. We validated the TaDiMa approach in a selection of possible scenarios for different PLM applications. The main benefit of the TaDiMa system is the easy and low-cost integration in the product lifecycle process. © 2009 Springer-Verlag.

Keywords: Industrial augmented reality | PLM | Tangible interfaces | Technical drawings and annotations

Abstract: We present a flexible framework for multimodal engineering applications using augmented reality. Our goal is to simplify the configuration procedures and to provide a higher grade of flexibility in multimodal interfaces. The system architecture is based on an extensible plug-in approach. A specific component has been designed to manage and synchronize the different multimodal inputs. A configurable XML based layer manages user preferences in a hierarchical way. We tested two engineering applications: a structural component re-design case and an industrial plant visualization. Industrial experts were positively impressed by the augmented visualization and by the usability of the interface. Most of them agree that the multimodal interface surpasses the desktop based interface.

Keywords: Augmented reality | Computer aided engineering | Multimodal interaction

Abstract: Large stereo displays and 3D input devices have proved significant productivity benefits in CAD, but they have also shown interaction weaknesses. We present a novel approach for pointing CAD entities with a 3D cursor on a wall-like stereoscopic display. We proved that the user error is affected by anisotropy, hence we present an enhanced snap tool called eSnap. This tool uses an elliptic metric for 3D cursor proximity. The provided results demonstrate a significant improvement in user performances and can be used as a guide for the development of user interfaces in emerging 3D displays. Copyright © 2008 Inderscience Enterprises Ltd.

Keywords: 3D input | CAD interaction | HCI | Large stereo displays | LSDs

Abstract: Multimodal interfaces are proved to increase the input\output bandwidth for a more efficient interaction in 3D activities. This work presents a novel framework designed to simplify the configuration procedures and to provide a high level of flexibility in multimodal interfaces. We propose an innovative system architecture to decouple input and output configuration from the application level and a multimodal engine designed to manage and synchronize the different inputs. The flexibility of the system is ensured by the use of a hierarchical XML-based configuration structure. This framework can be applied to test the advantage of multimodal interfaces in VRAD applications and provides tools to explore the synergy of different input\output techniques. © The Eurographics Association 2007.

Abstract: We have developed a pen device for CAD applications in virtual reality which provides novel features compared to existing systems. The SenStylus consists of a wireless pen designed to be ergonomically handled by the user for spatial interaction using a six degree of freedom optical tracking. In addition to the classic digital button(s) input, it provides analog multi-axial control, and a dual-rumble feedback output. We have integrated the device into an existing virtual reality CAD environment and extended the application functionalities with new devicespecific features. The SenStylus vibration feedback improves perception in the virtual world by controlling frequency, amplitude, and duration of the feedback, simulating a variety of responses during collisions and selection tasks. This capability enforces the visual depth sensitivity, which is critical when wo rking with complex CAD models. The multi-axial analog input provides a natural interaction paradigm to the user, thus simulating pen pressure and angle as in real world sketching and in real clay modeling. Dynamic tool-tip dimensioning and shaping are implemented as extra features. We present some applications to prove the added value of the SenStylus. The evaluation of the device received positive feedback by designers and engineers alike. The new features offered by this device can easily be extended to other VR applications using the API provided. Copyright UNION Agency - Science Press.

Keywords: 3D interaction | CAD | User interface hardware | Virtual reality

Abstract: In the fields of industrial design and car manufacturing the creation of 3D curves plays a fundamental role within the design process: it allows the improvement of the visual appeal of artifacts, it enhances ergonomics and the product's commercial competitiveness through product differentiation. When flexibility and intuition are to be privileged it is fundamental to achieve natural, intuitive, mathematically correct, creation and modification of surfaces. The scientific aim of this research is the development of an innovative metaphor to modeling of 3D curves which maintains the natural expertise of the designer. The major contribution of this paper is the capability of the system to create and modify the curve naturally, without mathematical artifices, within the limits set by the use of Bezier curves. The proposed metaphor combines the benefits of two acknowledged techniques referred to as the Digital Tape Drawing and the Eraser Pen, which allow the real-time modification of the curve. The integrated adoption of tangible interfaces and innovative mathematical tools, combined with the adoption of semi-immersive environment and lightweight interaction devices, delivers intuitive curve creation for free-form modeling within the virtual scene. The paper describes the details of the algorithm developed and it highlights its strengths during the styling phase. © 2004 ACM.

Keywords: 3D curve generation | Computer aided styling (CAS) | Virtual environments

Abstract: Commonly, during the aesthetic design process, stylists sketch features called character lines over a simple and "uninteresting" geometry (e.g. a car bonnet) in order to confer personality, emotional feeling and style. This work presents an original interface paradigm for character line sketching in a virtual reality environment. Taking advantage of the 3D interface, the feature path, also called leading line, can be directly sketched on the initial surface by realtime projection. Afterwards, a semi-transparent section is selected along the path in a interactive way and then the feature profile is sketched on this plane according the user's intention. Subsequently, by moving the virtual pen forwards along the path, the character line is generated, on the contrary if the pen is moved backwards the feature is partially erased. The distance of the virtual pen from the leading line controls, in real time, the offsetting along the path of the feature which remains consistent in style and identity. Such a system has been proven to be a powerful tool for fast expression and evaluation of ideas, which can be, in subsequent design phases, integrated with detailed surfacing applications and prototyping.

Keywords: Constrained-based design | Curve and surface design | Feature-based design | Parametric modelling

Abstract: Spacedesign is an innovative mixed reality (MR) application addressed to aesthetic design of free form curves and surfaces. It is a unique and comprehensive approach which uses task-specific configurations to support the design workflow from concept to mock-up evaluation and review. The first-phase conceptual design benefits from a workbench-like 3-D display for free hand sketching, surfacing and engineering visualization. Semitransparent stereo glasses augment the pre-production physical prototype by additional shapes, textures and annotations. Both workspaces share a common interface and allow collaboration and cooperation between different experts, who can configure the system for the specific task. A faster design workflow and CAD data consistency can be thus naturally achieved. Tests and collaborations with designers, mainly from automotive industry, are providing systematic feedback for this ongoing research. As far as the authors are concerned, there is no known similar approach that integrates the creation and editing phase of 3D curves and surfaces in virtual and augmented reality (VR/AR). Herein we see the major contribution of our new application.