Abstract: The Industry 5.0 paradigm emphasizes the importance of the operator’s well-being by seeing human-centricity as one of its cardinal principles. This enables a twofold benefit, improving the sustainability of the production process and enhancing performance. Improving performance and increasing operators’ safety is often related to cognitive load optimization. Confined spaces are working environments where elements of distraction, such as noise, can cause accidents with major, even fatal, consequences. Studies on the effects of noise on cognitive abilities present mixed results, and those concerning confined spaces are limited as they require an expensive experimental setup replicating the working scenario. Immersive Virtual Reality (IVR) technology enables overcoming this gap by replicating the experimental conditions in a synthetic environment. We exploited IVR to study noise’s impact on cognitive performance in confined spaces. We compared the impact of a stationary continuous noise source with an intermittent non-periodic one by administering the Stroop Color and Word Test. We also assessed the perceived cognitive effort by administering the modified noise-induced task load index questionnaire. We also compared the effects on the operator’s physiological activity through Heart Rate Variability (HRV) analysis. Results show that by keeping the equivalent noise level lower than 85 dB, noise has no statistically significant effects on cognitive performance and Heart Rate.

Keywords: Cognitive Performance | Heart Rate Variability | Noise Effects | Stroop Color and Word Test | Virtual Reality

Abstract: In response to the increasing number of traffic accidents, industrialized countries are investing in educational programs to raise awareness of safe driving. The most common type of intervention to reduce risky driving behaviors is the showing of traumatic experience videos related to the occurrence of traffic accidents caused by incorrect and high-risk driving habits. However, the effectiveness of this intervention depends on several factors, including how this content is experienced. Nowadays, thanks to Cinematic Virtual Reality (CVR) technologies, new modalities of video content fruition can be exploited. In this work, we implemented a CVR application to show 360° videos of traffic accidents and evaluate the effectiveness of CVR as an educational intervention tool to improve drivers’ attitudes toward traffic safety. A sample of 86 users aged 18 to 56 years answered a questionnaire on Attitudes Toward Traffic Safety Scale (ATTSS) administered before and after the CVR experience. In addition, a user experience questionnaire (UEQ) was administered. The results analysis of ATTSS questionnaires shows that the CVR experience increases risk awareness by inducing greater attention to safety while driving. Finally, the results of the UEQ questionnaire reveal that users positively evaluate the experience of using the system from hedonistic, pragmatic, and usability perspectives.

Keywords: 360 video | Educational Intervention | Traffic Safety | 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: Confined spaces cause fatal and serious injuries that tragically recur with similar dynamics every year. A survey carried out on the Italian territory by the National Institute for Insurance against Accidents at Work on the years from 2001 to 2019 shows that a total of 184 accidents occurred in confined spaces mostly because workers were poorly informed and trained, the risk assessment lacking, and that the provisions of the law were not respected. Often fatal events affect those involved in the primary incident and those who intervene in an attempt to assist. Consequently, it is necessary to apply a proper training process and extend it to all those involved in operations both inside and next to confined spaces. Traditionally, the training approach consists of classroom lectures and simulations in real environments. However, real simulation scenarios are costly and time-consuming as real scenarios training simulations require expensive purpose-built physical simulators. To overcome these limitations, we designed and implemented an Immersive Virtual Reality based platform to support and enforce the traditional confined space safety training approach. Finally, we defined an experimental validation procedure.

Keywords: Confined spaces | Immersive Virtual Reality | Safety training | Usability | Work safety

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: Industry 4.0 is characterized by great potential for innovation impacting the operator's role, increasingly engaged in smart activities of a decision-making nature. In such a working scenario, operators' working conditions can be effectively improved by applying a user-centered collaborative design approach. To this end, we developed a Virtual Reality-based multiplayer tool exploiting low-cost body tracking technology to evaluate ergonomic postural risk. The tool allows evaluating both in real-time and off-line the ergonomic postural risk according to the Rapid Upper Limb Assessment metrics. By applying this approach, a twofold advantage can be achieved. On the one hand, ergonomic experts can have an immersive three-dimensional visualization of postures even in off-line observations. On the other hand, it is possible to evaluate the ergonomics of workstations in the design phase by having the operator work on virtual mock-ups of workstations, thus allowing a sustainable approach to user-centered collaborative design.

Keywords: Collaborative design | Ergonomics | Kinect V2 | RULA | User-centered | Virtual Reality

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: 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: 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: Objectives: This study aims to evaluate the acceptability of Cinematic VR technology as a novel therapeutic approach supporting Social Skills Training (SST) rehabilitation interventions among patients with schizophrenia. Materials and Methods: We developed an innovative cinematic VR-based platform as a support system for SST rehabilitation of independent living skills and evaluated its acceptance among psychiatric patients in terms of usability, user experience, and use performance. Ten voluntary participants were enrolled in the study. The study inclusion criteria consisted of age 18-65 years, lack of moderate and severe intellectual disability, no substance use disorder, and schizophrenia spectrum disorder pathology according to DSM V. We administered post treatment questionnaires and developed the platform to capture relevant data automatically. Results: Patients rated usability and user experience from good to excellent. We also observed an improvement in the use performance. Conclusions: Cinematic Virtual Reality based applications showed good acceptability among patients with schizophrenia. This result supports further efforts in evaluating its effectiveness as a novel therapeutic approach supporting SST rehabilitation interventions.

Keywords: Cinematic virtual reality | Schizophrenia rehabilitation | Social skills training | Task performance | Usability | User experience

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: As noise is a pervasive element of work environments, it could affect workers' performance and wellbeing. In particular environments, such as confined spaces, noise could represent an even greater disruptor because reverberation effects amplify exposure levels and could affect cognitive abilities. The study of the effects of noise has mixed results in the literature and was scarcely investigated with reference to this application scenario. Nowadays, Immersive Virtual Reality (IVR) can simulate in a realistic way the working conditions in these environments and consequently simplify the investigations in this field that otherwise would be expensive and difficult to implement for safety reasons. In this work, we verify the ability of a current high-end IVR system to reproduce the acoustic conditions of a confined space realistically, and we evaluate the effects on user cognitive performance and user-perceived workload of a noise source typical of these industrial working environments.

Keywords: immersive virtual reality | N-back test | noise effects | NOISE-TLX | user experience | user performance

Abstract: The industrial transition to the 4.0 paradigm defines new scenarios in which the operator plays a central role within the industrial ecosystem. Thanks to the enabling technologies of Industry 4.0, it is possible to effectively improve operators' working conditions by applying the Human-Centered approach. Nowadays, one of the main challenges is to reduce work-related musculoskeletal disorders resulting from ergonomically incorrect working conditions in order to prevent the occurrence of occupational diseases. To this end, we developed a software tool that leverages a low-cost D-RGB camera (Kinect v2) to track the human body and an Augmented Reality (AR) visualization system based on Microsoft HoloLens 2. The tool assesses postural ergonomic risk in real-time according to the Rapid Upper Limb Assessment (RULA) metric. The proposed AR application allows a three-dimensional visualization of postures, which can be observed directly superimposed on the operator's body in the real scene. This approach aims to optimize the understanding of postures by creating a link between real information (operator's body) and virtual information (virtual skeleton, RULA score, and angles) by providing a simple and immediate user interface for ergonomists.

Keywords: Augmented Reality | Ergonomics | Hololens 2 | Human-Centered | Kinect v2 | RULA

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: 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: 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 study on cognitive workload is a field of research of high interest in the digital society. The implementation of 'Industry 4.0' paradigm asks the smart operators in the digital factory to accomplish more 'cognitive-oriented' than 'physical-oriented' tasks. The Authors propose an analytical model in the information theory framework to estimate the cognitive workload of operators. In the model, subjective and physiological measures are adopted to measure the work load. The former refers to NASA-TLX test expressing subjective perceived work load. The latter adopts Heart Rate Variability (HRV) of individuals as an objective indirect measure of the work load. Subjective and physiological measures have been obtained by experiments on a sample subjects. Subjects were asked to accomplish standardized tasks with different cognitive loads according to the 'n-back' test procedure defined in literature. Results obtained showed potentialities and limits of the analytical model proposed as well as of the experimental subjective and physiological measures adopted. Research findings pave the way for future developments.

Keywords: Cognitive load | Heart rate variability | Information theory model | NASA-TLX | Smart operators

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: A number of studies have recently demonstrated that the geometry of scaffolds for bone tissue engineering significantly affects the tissue differentiation process and the rate of bone tissue regeneration. These findings and the possibility of fabricating any kind of sophisticated geometries by additive manufacturing techniques led many researchers throughout the world to investigate strategies for the design of scaffolds and for the optimization of their geometry. In this chapter, after revising the numerical optimization algorithms recently implemented to determine the best scaffold geometry we will investigate, in particular, those that are mechanobiology-driven. These algorithms perturb the scaffold microarchitecture until the optimal scaffold geometry, i.e., the geometry that allows maximizing the amounts of bone forming within the scaffold pores, is computed. Different applications of these algorithms to different regular and irregular scaffold geometries will be shown.

Keywords: Beam-based scaffold | Irregular scaffold | Mechanobiology | Mechanoregulation algorithm | Regular scaffold

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: 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 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: 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: 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: 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: 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