Mechanosensitivity and Neural Adaptation in Human Somatosensory System

Magnetoencephalography (MEG) was utilized to characterize the adaptation in the somatosensory cortical network due to repeated cutaneous tactile stimulation applied unilaterally on the face and hand using a custom-built pneumatic stimulator called the TAC-Cell. Face stimulation invoked neuromagnetic responses reflecting cortical activity in the contralateral primary somatosensory cortex (SI), while hand stimulation resulted in robust contralateral SI and posterior parietal cortex (PPC) activation. There was also activity observed in regions of the secondary somatosensory cortical areas (SII), although with a reduced amplitude and higher variability across subjects. There was a significant difference in adaptation rates between SI, and higher-order sensory cortices like the PPC for hand stimulation. Adaptation was also significantly dependent on the stimulus frequency and pulse index number within the stimulus train for both hand and face stimulation. The latency of the peak responses was significantly dependent on stimulus site and response component (SI, PPC). The difference in the latency of peak SI and PPC responses can be reflective of a hierarchical serial-processing network in the somatosensory cortex. Age- and sex-related changes of vibrotactile sensitivity in the orofacial and hand skin surfaces of healthy adults was demonstrated using an established psychophysical protocol. Vibrotactile threshold sensitivity increased as a function of age for finger stimulation, but remained unaltered for the face. Increase in the finger threshold sensitivity is due to age-related changes in the number and morphology of Pacinian corpuscles (absent in the face). Vibrotactile threshold sensitivity is significantly dependent on stimulation site, stimulus frequency, and sex of the participant. These differences are presumably due to dissimilarities in the type and density of mechanoreceptors present in the face and hand. A novel-method was developed to couple the use of fiber-optic displacement sensors with the pneumatic stimulator built in our laboratory called the TAC-Cell. This displacement sensor which is commonly used in industrial applications was successfully utilized to characterize the skin response to TAC-Cell stimulation. Skin displacement was significantly dependent on input stimulus amplitudes and varied as a function of the participants' sex. Power spectrum analysis and rise-fall time measurement of the skin-displacement showed that the TAC-Cell stimulus consists of a spectrally rich, high velocity signal that is capable of evoking a cortical response due to stimulation of the medial-lemniscus and trigeminal pathways

Curved Displays, Empirical Horopters, and Ergonomic Design Guidelines

Department of Human Factors EngineeringVisual display products should be comprehensively evaluated from the perspectives of productivity, safety, and well-being. Curved display products are known to provide advantages. Although previous studies found that curved displays increase visual task performance, reduce visual fatigue, and improve the watching experience, these studies did not comprehensively examine the effects of display curvature. Moreover, they used low-fidelity curved screens that may not effectively reflect actual curved displays. The purpose of this thesis was to develop ergonomic design guidelines for determining appropriate display curvatures, considering the productivity, safety, and well-being of visual display terminal (VDT) users. Two studies on monitors and one study on TVs were conducted for this goal. In Study 1, the effects of the display curvature, display zone, and task duration on visual task performance and visual fatigue during a visual search task on a 50-inch multi-monitor were investigated. In Study 2, the effects of the display curvature and task duration on visual task performance, visual fatigue, and user satisfaction during a proofreading task on a 27-inch monitor were investigated, and the associations between ergonomic evaluation elements were then examined. Prediction models of visual fatigue and user satisfaction were subsequently developed. In Study 3, the effects of the display curvature, viewing distance, and lateral viewing position on presence, visual comfort, and user satisfaction during a TV watching task on a 55-inch TV were examined, and the importance of six viewing experience elements affecting user satisfaction was revealed. Finally, ergonomic design guidelines for curved displays were suggested. Based on the results of studies 1 and 2, an appropriate rest-break time was ecommended, taking into account visual task performance and visual fatigue. Study 1 examined the effects of the display curvature (400 R, 600 R, 1200 R, and flat), display zone (five zones), and task duration (15 and 30 min) on legibility and visual fatigue. A total of 27 participants completed two sets of 15-minute visual search tasks with each curvature setting. The 600 R and 1200 R settings yielded better results compared to the flat setup regarding legibility and perceived visual fatigue. Relative to the corresponding center zone, the outermost zones of the 1200 R and flat settings showed a decrease of 8%???37% in legibility, whereas those of the flat environment showed an increase of 26%???45% in perceived visual fatigue. Across curvatures, legibility decreased by 2%???8%, whereas perceived visual fatigue increased by 22% during the second task set. The two task sets showed an increase of 102% in the eye complaint score and a decrease of 0.3 Hz in the critical fusion frequency, both of which indicated a rise in visual fatigue. To sum up, a curvature of around 600 R, central display zones, and frequent breaks were recommended to improve legibility and reduce visual fatigue. Study 2 examined the effects of the display curvature and task duration on proofreading performance, visual discomfort, visual fatigue, mental workload, and user satisfaction. Fifty individuals completed four 15-min proofreading tasks at a particular curvature setting. Five display curvatures (600 R, 1140 R, 2000 R, 4000 R and flat) and five task durations (0, 15, 30, 45, and 60 min) were incorporated. The mean proofreading speed at its highest when the display curvature radius was equal to the viewing distance (600 R). Across curvatures, speedaccuracy tradeoffs occurred with proofreading, as indicated by an increase of 15.5% in its mean speed and a decrease of 22.3% in its mean accuracy over one hour. Meanwhile, the mean perceived visual discomfort, subjective visual fatigue, and mental workload increased, by 54%, 74%, and 24% respectively, during the first 15-min of proofreading. A decrease of 0.4 Hz in the mean critical fusion frequency during the first 15 min and a reduction in the mean blink frequency also indicated increases in visual fatigue and mental workload. The mean user satisfaction decreased by 11% until 45 min. A segmented regression model, in which perceived visual discomfort was used as a predictor, attributed 51% of the variability to visual fatigue. To sum up, a curvature of 600 R was recommended for speedy proofreading. Moreover, the breakpoint was observed be flexible, depending on VDT task types. These findings can contribute to determining ergonomic display curvatures and scheduling interim breaks for speedy but less visually fatiguing proofreading. Study 3 examined the effects of the display curvature, viewing distance, and lateral viewing position on the TV watching experience. The watching experience was assessed regarding the spatial presence, engagement, ecological validity, negative effects, visual comfort, image quality, and display satisfaction. Four display curvatures (2.3 m, 4 m, 6 m, and flat), two viewing distances (2.3 m and 4 m), and five lateral viewing positions (0 cm, 35 cm, 70 cm, 105 cm, and 140 cm) were evaluated. Seven pairs of individuals per curvature watched ten 5 min videos together, each time at a different viewing distance and lateral viewing position. Spatial presence and engagement increased when the display curvature approached the given viewing distance. Regardless of display curvature and viewing distance and TV watching experience factors, except negative effects, were degraded at more lateral viewing positions. Engagement could effectively explain the display satisfaction. These findings can contribute to enhancing TV watching experiences by recommending specific levels of display curvatures, viewing distances, and lateral viewing positions, as well as providing information on the relative importance of each watching experience element. This work suggested ergonomic design guidelines for curved displays. In Study 1, a curvature of approximately 600 R, central display zone, and frequent breaks were proposed to improve legibility and reduce visual fatigue during visual search tasks at the viewing distance of 500 mm. In Study 2, a curvature radius of 600 R and a minimum 15-minute break interval were proposed for a speedy proofreading task, at the viewing distance of 600 mm. In Study 3, a display radius of curvature similar to the viewing distance was recommended to improve the viewing experience. These results support that a curved display is ergonomically more beneficial when the display curvature approaches the empirical horopter. A relatively short 15-minute rest-time interval was suggested, considering the decrease of task accuracy and the increase of visual fatigue in studies 1 and 2. Two regression models were selected in Study 2 regarding predictive accuracy. They accounted for 70.4% of subjective visual fatigue variability and 60.2% of user satisfaction variability. Although this work was performed using relatively higher-fidelity mock-ups than previous studies, it is necessary to verify the findings with actual curved display products in the future. Furthermore, various tasks (e.g., word processing, graphics design, and gaming) and personal characteristics (e.g., presbyopia, gender, visual acuity, and product experience) should be considered to generalize the results of this thesis. These results can contribute to determining the ergonomic display curvature in consideration of productivity, safety, and well-being, and prioritizing elements of the visual fatigue and user satisfaction resulting from VDT work.ope

Proceedings XXIII Congresso SIAMOC 2023

Il congresso annuale della Società Italiana di Analisi del Movimento in Clinica (SIAMOC), giunto quest’anno alla sua ventitreesima edizione, approda nuovamente a Roma. Il congresso SIAMOC, come ogni anno, è l’occasione per tutti i professionisti che operano nell’ambito dell’analisi del movimento di incontrarsi, presentare i risultati delle proprie ricerche e rimanere aggiornati sulle più recenti innovazioni riguardanti le procedure e le tecnologie per l’analisi del movimento nella pratica clinica. Il congresso SIAMOC 2023 di Roma si propone l’obiettivo di fornire ulteriore impulso ad una già eccellente attività di ricerca italiana nel settore dell’analisi del movimento e di conferirle ulteriore respiro ed impatto internazionale. Oltre ai qualificanti temi tradizionali che riguardano la ricerca di base e applicata in ambito clinico e sportivo, il congresso SIAMOC 2023 intende approfondire ulteriori tematiche di particolare interesse scientifico e di impatto sulla società. Tra questi temi anche quello dell’inserimento lavorativo di persone affette da disabilità anche grazie alla diffusione esponenziale in ambito clinico-occupazionale delle tecnologie robotiche collaborative e quello della protesica innovativa a supporto delle persone con amputazione. Verrà infine affrontato il tema dei nuovi algoritmi di intelligenza artificiale per l’ottimizzazione della classificazione in tempo reale dei pattern motori nei vari campi di applicazione

Filtering of image sequences: on line edge detection and motion reconstruction

L'argomento della Tesi riguarda líelaborazione di sequenze di immagini, relative ad una scena in cui uno o pi˘ oggetti (possibilmente deformabili) si muovono e acquisite da un opportuno strumento di misura. A causa del processo di misura, le immagini sono corrotte da un livello di degradazione. Si riporta la formalizzazione matematica dellíinsieme delle immagini considerate, dellíinsieme dei moti ammissibili e della degradazione introdotta dallo strumento di misura. Ogni immagine della sequenza acquisita ha una relazione con tutte le altre, stabilita dalla legge del moto della scena. Líidea proposta in questa Tesi Ë quella di sfruttare questa relazione tra le diverse immagini della sequenza per ricostruire grandezze di interesse che caratterizzano la scena. Nel caso in cui si conosce il moto, líinteresse Ë quello di ricostruire i contorni dellíimmagine iniziale (che poi possono essere propagati attraverso la stessa legge del moto, in modo da ricostruire i contorni della generica immagine appartenente alla sequenza in esame), stimando líampiezza e del salto del livello di grigio e la relativa localizzazione. Nel caso duale si suppone invece di conoscere la disposizione dei contorni nellíimmagine iniziale e di avere un modello stocastico che descriva il moto; líobiettivo Ë quindi stimare i parametri che caratterizzano tale modello. Infine, si presentano i risultati dellíapplicazione delle due metodologie succitate a dati reali ottenuti in ambito biomedicale da uno strumento denominato pupillometro. Tali risultati sono di elevato interesse nellíottica di utilizzare il suddetto strumento a fini diagnostici

A CAD-based modeling for dynamic visualization of urban environments in piecemeal (incremental) growth

Thesis (Master)--Izmir Institute of Technology, City and Regional Planning, Izmir, 2002Includes bibliographical references (leaves: 114-122)Text in English; Abstract: Turkish and Englishxi, 122 leavesVisualization is inherent to the conduct of urban design as a direct connection between the designer and three dimensional reality of urban settlements. Visualization of urban environments and urban design projects is vital, since most designers prefer to understand place and context through visualization. The reasons for visualization in urban design can be classified under three headings: .visual thinking, design communication and testing mechanism. Digital revolution. has improved computer use in urban design, as in many other fields. Dynamic computer models can present an ideal environment to visualize the change in respect to time. Digital tools are much more efficient than conventional methods in explaining the growth and change of urban environments. Especially, incremental growth requires features not found in .static/analog. media. Christopher Alexander and his colleagues, in their book .A New Theory of Urban Design., tried to justify their ideas about piecemeal growth by an experiment. The analog methods, such as physical models, two-dimensional diagrams, have been used to conduct the experiment and to convey their ideas about the design process. This thesis tries to produce a .dynamic/digital. model that could be utilized in their experiment instead of static/analog methods. Spatial data should be considered as dynamic, or changing identities rather than as simple, static features. Time is an example of a dynamic component of a spatial data set. Recent technological developments are increasing computer hardware and software capabilities so that this dynamic aspect of data can be accounted for by today.s systems. Dynamic data have not been a great concern in digital technologies for many years, but today changing patterns and dimensions are becoming more important

Human Machine Interfaces for Teleoperators and Virtual Environments

In Mar. 1990, a meeting organized around the general theme of teleoperation research into virtual environment display technology was conducted. This is a collection of conference-related fragments that will give a glimpse of the potential of the following fields and how they interplay: sensorimotor performance; human-machine interfaces; teleoperation; virtual environments; performance measurement and evaluation methods; and design principles and predictive models

Worker and Public Health and Safety

This book on "Worker and Public Health and Safety: Current Views" brings together current scholarly work and opinions in the form of original papers and reviews related to this field of study. It provides important and recent scientific reading as well as topical medical and occupational information and research in areas of immediate relevance, such as chronic and occupational diseases, worker safety and performance, job strain, workload, injuries, accident and errors, risks and management, fitness, burnout, psychological and mental disorders including stress, therapy, job satisfaction, musculoskeletal symptoms and pain, socio-economic factors, dust pollution, pesticides, noise, pathogens, and related areas

Human Machine Interaction

In this book, the reader will find a set of papers divided into two sections. The first section presents different proposals focused on the human-machine interaction development process. The second section is devoted to different aspects of interaction, with a special emphasis on the physical interaction

Audio for Virtual, Augmented and Mixed Realities: Proceedings of ICSA 2019 ; 5th International Conference on Spatial Audio ; September 26th to 28th, 2019, Ilmenau, Germany

The ICSA 2019 focuses on a multidisciplinary bringing together of developers, scientists, users, and content creators of and for spatial audio systems and services. A special focus is on audio for so-called virtual, augmented, and mixed realities. The fields of ICSA 2019 are: - Development and scientific investigation of technical systems and services for spatial audio recording, processing and reproduction / - Creation of content for reproduction via spatial audio systems and services / - Use and application of spatial audio systems and content presentation services / - Media impact of content and spatial audio systems and services from the point of view of media science. The ICSA 2019 is organized by VDT and TU Ilmenau with support of Fraunhofer Institute for Digital Media Technology IDMT

Aerospace medicine and biology: A continuing bibliography with indexes (supplement 385)

This bibliography lists 536 reports, articles and other documents introduced into the NASA Scientific and Technical Information System Database. Subject coverage includes: aerospace medicine and physiology, life support systems and man/system technology, protective clothing, exobiology and extraterrestrial life, planetary biology, and flight crew behavior and performance