Human factors and ergonomics

High-fidelity medical simulations refer to the use of computerized mannequins that simulate real-life scenarios. It is important to avoid stress and cognitive overload of students in order to ensure a productive learning. This study concerns the identification and assessment of events related to intrinsic cognitive loads (ICL), extraneous cognitive loads (ECL) and stress episodes through the analysis of physiological parameters. 170 students were enrolled in the study. Analysed heart rate (HR) and electrodermal activity (EDA) were acquired through Empatica E4 wristband. Cognitive load assessment was performed by evaluating peaks in HR, associable with ICL or ECL through video analysis. The stressful events were assessed considering EDA in relation to HR, according to Russell's circumplex plan. Results show good achievements in students' performance and an ICL increment and an ECL decrement during simulation repetition. The stressful conditions increase with the increasing difficulty of the simulations.

Keywords: Cognitive load , Human factor , Medical simulation , Stress , Training

Robotics for Medicine and Healthcare is undoubtedly an important emerging sector of the newborn third millennium. There are many aspects in which this branch of robotics already operates; in this article, the focus will be on the so-called “Robotic assistive technology”. In particular, a novel electromechanical design for an assistive Hand Exoskeleton System is presented here. Since freedom of movement plays a crucial role in making actually usable an assistive device, the main point of innovation of the proposed solution lies in the complete wearability of the resulting system: including mechanics, control electronics, and power supply. From the combination of the authors' previous experience with the improvements presented in this article comes a fully standalone tailor-made assistive device.

In this paper, a very tiny HW design of a Quantized Fully Convolutional Neural Network is proposed which demonstrates that accurate Human Posture Recognition can be designed by exploiting only pressure sensors and keeping the computation close to the data sources, according to the edge computing paradigm. The custom design of the QFCN exploits a base-2 quantization scheme to achieve state-of-The-Art performances in terms of classification accuracy, together with a very reduced number of mapped physical resources and power consumption. Trained and validated on a public dataset for in-bed posture classification, the QFCN exhibits an accuracy up to 96.77% in recognizing 17 different postures. When prototyped on a Xilinx Artix 7 FPGA the design achieves less than 7 mW dynamic power dissipation and a maximum operation frequency of 26.6 MHz, compatible with an Output Data Rate (ODR) of the sensors of 9.13 kHz.

Keywords: Convolutional neural network , FPGA custom design , low-power digital design , Quantization scheme

A custom HW design of a Fully Convolutional Neural Network (FCN) is presented in this paper to implement an embeddable Human Posture Recognition (HPR) system capable of very high accuracy both for laying and sitting posture recognition. The FCN exploits a new base-2 quantization scheme for weight and binarized activations to meet the optimal trade-off between low power dissipation, a very reduced set of instantiated physical resources and state-of-the-art accuracy to classify human postures. By using a limited number of pressure sensors only, the optimized HW implementation allows keeping the computation close to the data sources according to the edge computing paradigm and enables the design of embedded HP systems. The FCN can be simply reconfigured to be used for laying and sitting posture recognition. Tested on a public dataset for in-bed posture classification, the proposed FCN obtains a mean accuracy value of 96.77% to recognize 17 different postures, while a small custom dataset has been used for training and testing for sitting posture recognition, where the FCN achieves 98.88% accuracy to recognize eight positions. The FCN has been prototyped on a Xilinx Artix 7 FPGA where it exhibits a dynamic power dissipation lower than 11 mW and 7 mW for laying and sitting posture recognition, respectively, and a maximum operation frequency of 47.64 MHz and 26.6 MHz, corresponding to an Output Data Rate (ODR) of the sensors of 16.50 kHz and 9.13 kHz, respectively. Furthermore, synthesis results with a CMOS 130 nm technology have been reported, to give an estimation about the possibility of an in-sensor circuital implementation.

Keywords: Convolutional Neural Network , Human behavior , Low-power digital design , Posture recognition

BACKGROUND: Human-centred design asks for wellbeing and comfort of the customer/worker when interacting with a product. Having a good perception-model and an objective method to evaluate the experienced (dis)comfort by the product user is needed for performing a preventive comfort evaluation as early as possible in the product development plan. The mattress of a bed is a typical product whose relevance in everyday life of people is under-evaluated. Fortunately, this behaviour is quickly changing, and the customer wants to understand the product he/she buys and asks for more comfortable and for scientifically assessed products. No guidelines for designing a personalized mattress are available in the literature. OBJECTIVES: This study deals with the experience of designing an innovative product whose product-development-plan is focused on the customer perceived comfort: a personalized mattress. The research question is: which method can be used to innovate or create a comfort-driven human-centred product? METHODS: Virtual prototyping was used to develop a correlated numerical model of the mattress. A comfort model for preventively assessing the perceived comfort was proposed and experimentally tested. Mattress testing sessions with subjects were organized, and collected data were compared with already tested mattresses. Brainstorming and multi-expert methods were used to propose, realize, and test an archetype of a new mattress for final comfort assessment. RESULTS: A new reconfigurable mattress was developed, resulting in two patents. The mattress design shows that personalized products can be tuned according to the anthropometric data of the customer in order to improve the comfort experience during sleep. CONCLUSIONS: A 'comfort-driven design guideline' was proposed; this method has been based on the use of virtual prototyping, virtual optimization and physical prototyping and testing. It allowed to improve an existing product in a better way and to bring innovation in it.

Keywords: Comfort , design , innovation , mattress , personalized product

This study is aimed at evaluating the impact of different technical solutions of a virtual reality simulator to support the assessment of advanced human–machine interfaces for hydraulic excavator based on a new coordinated control paradigm and haptic feedbacks. By mimicking the end-effector movements, the control is conceived to speed up the learning process for novice operators and to reduce the mental overload on those already trained. The design of the device can fail if ergonomics, usability and performance are not grounded on realistic simulations where the combination of visual, auditory and haptic feedbacks make the users feel like being in a real environment rather than a computer-generated one. For this reason, a testing campaign involving 10 subjects was designed to discriminate the optimal set-up for the hardware to ensure a higher immersion into the VR experience. Both the audio–video configurations of the simulator (head-mounted display and surround system vs. monitor and embedded speakers) and the two types of haptic feedback for the soil–bucket interaction (contact vs. shaker) are compared in three different scenarios. The performance of both the users and simulator are evaluated by processing subjective and objective data. The results show how the immersive set-up improves the users' efficiency and ergonomics without putting any extra mental or physical effort on them, while the preferred haptic feedback (contact) is not the more efficient one (shaker).

Keywords: Excavator coordinated control , Haptic control , Human–machine interface , Multi-sensory feedbacks , Virtual reality simulator

The research work presents a specific procedure to evaluate the performance of soccer goalkeepers by means of a marker-less motion capture (Mocap) system based on a set of 8 GoPro active cameras. The layout of the sensors and the calibration phase have been defined to be easily replicated and not to interfere with athletes and trainers during the exercises. The proposed solution has been tested in collaboration with goalkeeper coaches, who made available the knowledge about conventional training exercise. The Mocap system has been tested by involving two goalkeepers and a coach. The results have been elaborated and the outcomes have been considered interesting by experts. Furthermore, the adopted technology for motion capture and elaboration could be evaluated for an application to the rehabilitation process of an athlete after an injury, to determine his stage of recovery and the most suitable work to be done.

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

The study of the human body and its movements is still a matter of great interest today. Most of these issues have as their fulcrum the study of the balance characteristics of the human body and the determination of its Centre of Mass. In sports, a lot of attention is paid to improving and analysing the athlete's performance. Almost all the techniques for determining the Centre of Mass make use of special sensors, which allow determining the physical magnitudes related to the different movements made by athletes. In this paper, a markerless method for determining the Centre of Mass of a subject has been studied, comparing it with a direct widely validated equipment such as the Wii Balance Board, which allows determining the coordinates of the Centre of Pressure. The Motion Capture technique was applied with the OpenPose software, a Computer Vision method boosted with the use of Convolution Neural Networks. Ten quasi-static analyses have been carried out. The results have shown an error of the Centre of Mass position, compared to that obtained from the Wii Balance Board, which has been considered acceptable given the complexity of the analysis. Furthermore, this method, despite the traditional methods based on the use of balances, can be used also for prediction of the vertical position of the Centre of Mass.

Keywords: 3D motion capture , Convolution neural networks , Open Pose

The main aim of the CASTLE (Cabin System Design Towards Passenger Wellbeing) European project is to deliver innovative interiors solutions that maximize the comfort and wellbeing of passengers in the next future. To achieve such objective, an effective HCD (Human Centred Design) approach has been employed to derive a Human Response Model based on a holistic assessment of comfort. The overall methodology has been conceived to provide different tools and methods to collect data on the impact that the design of each cabin item has on the user from the earliest design stages. One of these tools is represented by using 3D virtual mock-ups to capture data on the user's perception and to rate the level of appreciation inspired by the specific design. In this paper we present the experimental procedures and the results from a preliminary experimental campaign of Human in the loop simulations in Virtual/Augmented Reality of a Regional Aircraft.

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

Despite the great potential of Virtual Reality (VR) to arouse emotions, there are no VR affective databases available as it happens for pictures, videos, and sounds. In this paper, we describe the validation of ten affective interactive Virtual Environments (VEs) designed to be used in Virtual Reality. These environments are related to five emotions. The testing phase included using two different experimental setups to deliver the overall experience. The setup did not include any immersive VR technology, because of the ongoing COVID-19 pandemic, but the VEs were designed to run on stereoscopic visual displays. We collected measures related to the participants' emotional experience based on six discrete emotional categories plus neutrality and we included an assessment of the sense of presence related to the different experiences. The results showed how the scenarios can be differentiated according to the emotion aroused. Finally, the comparison between the two experimental setups demonstrated high reliability of the experience and strong adaptability of the scenarios to different contexts of use.

Computer graphics is-in many cases-about visualizing what you cannot see. However, virtual reality (VR), from its beginnings, aimed at stimulating all human senses: not just the visual channel. Moreover, this set of multisensory stimuli allows users to feel present and able to interact with the virtual environment. In this way, VR aims to deliver experiences that are comparable to real-life ones in their level of detail and stimulation, intensity, and impact. Hence, VR is not only a means to see, but also to feel differently. With the spreading of VR technologies, there is a growing interest in using VR to evoke emotions, including positive and negative ones. This article discusses the current possibilities and the authors' experience collected in the field in trying to elicit emotions through VR. It explores how different design aspects and features can be used, describing their contributions and benefits in the development of affective VR experiences. This work aims at raising awareness of the necessity to consider and explore the full design space that VR technology provides in comparison to traditional media. Additionally, it provides possible tracks of VR affective applications, illustrating how they could impact our emotions and improve our life, and providing guidelines for their development.

Nowadays, User eXperience (UX) is one of the main concerns in developing innovative products. This research develops the way to define and exploit guidelines for interactive redesign of the UX of products. Because of their origin, these guidelines will encompass all UX characteristics reputed as meaningful like usefulness, subjective feelings, motivational aspects, emotions, etc.; moreover, the redesign suggestions offered by these guidelines, as well as the procedures to collect and analyse the data to define other guidelines and suggest the best ways to implement them, push different competencies (engineers, UX experts, psychologists, etc.) to work in synergy, just like an interactive design context requires.

Keywords: CUE model , Interactive UX redesign guidelines , irMMs-based method , Mental models , Product User eXperience

PERSEL (PERsonality SELector) is a personality-based selection tool to maximize UX redesign effectiveness by highlighting the best users to involve time by time in the activities due to the target the UX redesign of products aims at. To date, PERSEL knowledge base was populated using a top-down approach; the literature allowed highlighting relationships between personality traits and UX characteristics. Here, the bottom-up approach aims at generating fresh pieces of information to integrate PERSEL knowledge base by looking at experiences in the field. A questionnaire-based survey allows collecting data about the personality of the participants, together with their inclinations towards UX. The statistical analysis of the collected data highlights further relationships among personality traits, UX characteristics and using metrics like novelty, variety and usefulness of the users' possible suggestions.

Keywords: PERSEL , Personality , Product redesign , User eXperience

User eXperience (UX) gains more and more importance due to technological complexity, task specialization, widening of users range, etc. All of this become particularly true in medical contexts, where affordance, empathy with devices, natural interaction, dialogue reliability, real time response, etc., can make the difference for completely successful surgical activities. The PIRG - Product Innovation Research Group and the Clinic of Maxillo-facial Surgery of the University of Udine worked together for investigating about the UX during maxillo-facial surgery planning and implementation. The goal was double-faced: analyze the UX in order to highlight possible needs for improvements and test the evaluation process in terms of tools and activities performed. The outcome consists of suggestions to improve the UX and of a review of the evaluation process.

Keywords: Heuristic evaluation , Maxillo-facial surgery , User eXperience (UX)

This paper introduces a low-cost and low computational marker-less motion capture system based on the acquisition of frame images through standard RGB cameras. It exploits the open-source deep learning model CMU, from the tf-pose-estimation project. Its numerical accuracy and its usefulness for ergonomic assessment are evaluated by a proper experiment, designed and per-formed to: (1) compare the data provided by it with those collected from a motion capture golden standard system; (2) compare the RULA scores obtained with data provided by it with those obtained with data provided by the Vicon Nexus system and those estimated through video analysis, by a team of three expert ergonomists. Tests have been conducted in standardized laboratory conditions and involved a total of six subjects. Results suggest that the proposed system can predict angles with good consistency and give evidence about the tool's usefulness for ergonomist.

Keywords: Ergonomic risk assessment , Industrial ergonomics , Motion capture , Postural analysis , RULA

This article reports the results of a research aimed to evaluate the ability of a haptic interface to improve the user experience (UX) with virtual museum systems. In particular, two user studies have been carried out to (1) compare the experience aroused during the manipulation of a 3D printed replica of an artifact with a pen-like stylus with that aroused during the interaction (visual and tactile) with a 3D rendering application using a haptic interface and PC monitor, and (2) compare the users' perceived usability and UX among a traditional mouse-based desktop interface, haptic interface, and haptic gamified interface based on the SUS scale and the AttrakDiff2 questionnaire. A total of 65 people were involved. The considered haptic application is based on the haptic device Omega 6 produced by Force Dimension, and it is a permanent attraction of the Museo Archeologico Nazionale delle Marche. Results suggest that the proposed haptic interface is suitable for people who commonly use mouse-based computer interaction, but without previous experience with haptic systems, and provide some insights useful to better understand the role of haptic feedback and gamification in enhancing UX with virtual museums, and to guide the development of other similar applications in the future.

Keywords: haptic interface , user experience , Virtual museum , virtual reality

Driver behaviour recognition is of paramount importance for in-car automation assistance. It is widely recognized that not only attentional states, but also emotional ones have an impact on the safety of the driving behaviour. This research work proposes an emotion-aware in-car architecture where it is possible to adapt driver's emotions to the vehicle dynamics, investigating the correlations between negative emotional states and driving performances, and suggesting a system to regulate the driver's engagement through a unique user experience (e.g. using music, LED lighting) in the car cabin. The relationship between altered emotional states induced through auditory stimuli and vehicle dynamics is investigated in a driving simulator. The results confirm the need for both types of information to improve the robustness of the driver state recognition function and open up the possibility that auditory stimuli can modify driving performance somehow.

Keywords: Driver monitoring system , Emotion recognition , Facial expression recognition

The human-robot synergy is a key pillar of the smart factory of the future, aiming at high performance in a risk-free environment. Analyzing the main research themes in this field, a need for design criteria balancing emerges. Safety, ergonomics, productivity, and flexibility are the main requirements to be properly considered and combined. The paper proposes a method to fulfill this goal when designing the collaboration between humans and robots. It also exploits emerging technologies for real-time mapping of the workspace and operations management able to facilitate and simulate this interaction. Opportunities and benefits are presented through a real case study.

Keywords: Collaborative robots , Ergonomics , Human-robot collaboration , Industry 4.0 , Workstation design

This paper analyses the design and measurement issues that deal with the development of uterine balloon tamponade devices to treat post-partum haemorrhage to be used in low-resource settings. This emergency situation requires low-cost, reliable, and easy-to-use solutions to stop the bleeding quickly. The analysis highlights that, although solutions are already available, still, there are issues concerning the quantification of blood lost volume, the measure of the pressure applied by the tamponade system to the uterine walls, and the lack of a user-centred design approach focused on the woman.

Keywords: Maternal mortality , Post-partum haemorrhage , User-centred design