88 research outputs found
Aerospace medicine and biology: A continuing bibliography with indexes (supplement 341)
This bibliography lists 133 reports, articles and other documents introduced into the NASA Scientific and Technical Information System during September 1990. Subject coverage includes: aerospace medicine and psychology, life support systems and controlled environments, safety equipment, exobiology and extraterrestrial life, and flight crew behavior and performance
Dataglove Measurement of Joint Angles in Sign Language Handshapes
In sign language research, we understand little about articulatory factors involved in shaping phonemic boundaries or the amount (and articulatory nature) of acceptable phonetic variation between handshapes. To date, there exists no comprehensive analysis of handshape based on the quantitative measurement of joint angles during sign production. The purpose of our work is to develop a methodology for collecting and visualizing quantitative handshape data in an attempt to better understand how handshapes are produced at a phonetic level. In this pursuit, we seek to quantify the flexion and abduction angles of the finger joints using a commercial data glove (CyberGlove; Immersion Inc.). We present calibration procedures used to convert raw glove signals into joint angles. We then implement those procedures and evaluate their ability to accurately predict joint angle. Finally, we provide examples of how our recording techniques might inform current research questions
Tactile Roughness Perception of Virtual Gratings by Electrovibration
Realistic display of tactile textures on touch screens is a big step forward
for haptic technology to reach a wide range of consumers utilizing electronic
devices on a daily basis. Since the texture topography cannot be rendered
explicitly by electrovibration on touch screens, it is important to understand
how we perceive the virtual textures displayed by friction modulation via
electrovibration. We investigated the roughness perception of real gratings
made of plexiglass and virtual gratings displayed by electrovibration through a
touch screen for comparison. In particular, we conducted two psychophysical
experiments with 10 participants to investigate the effect of spatial period
and the normal force applied by finger on roughness perception of real and
virtual gratings in macro size. We also recorded the contact forces acting on
the participants' finger during the experiments. The results showed that the
roughness perception of real and virtual gratings are different. We argue that
this difference can be explained by the amount of fingerpad penetration into
the gratings. For real gratings, penetration increased tangential forces acting
on the finger, whereas for virtual ones where skin penetration is absent,
tangential forces decreased with spatial period. Supporting our claim, we also
found that increasing normal force increases the perceived roughness of real
gratings while it causes an opposite effect for the virtual gratings. These
results are consistent with the tangential force profiles recorded for both
real and virtual gratings. In particular, the rate of change in tangential
force () as a function of spatial period and normal force followed
trends similar to those obtained for the roughness estimates of real and
virtual gratings, suggesting that it is a better indicator of the perceived
roughness than the tangential force magnitude.Comment: Manuscript received June 25, 2019; revised November 15, 2019;
accepted December 11, 201
Haptics: Science, Technology, Applications
This open access book constitutes the proceedings of the 13th International Conference on Human Haptic Sensing and Touch Enabled Computer Applications, EuroHaptics 2022, held in Hamburg, Germany, in May 2022. The 36 regular papers included in this book were carefully reviewed and selected from 129 submissions. They were organized in topical sections as follows: haptic science; haptic technology; and haptic applications
Combined spatial and frequency encoding for electrotactile feedback of myoelectric signals
Electrotactile stimulation has been commonly used in human–machine interfaces to provide feedback to the user, thereby closing the control loop and improving performance. The encoding approach, which defines the mapping of the feedback information into stimulation profiles, is a critical component of an electrotactile interface. Ideally, the encoding will provide a high-fidelity representation of the feedback variable while being easy to perceive and interpret by the subject. In the present study, we performed a closed-loop experiment wherein discrete and continuous coding schemes are combined to exploit the benefits of both techniques. Subjects performed a muscle activation-matching task relying solely on electrotactile feedback representing the generated myoelectric signal (EMG). In particular, we investigated the performance of two different coding schemes (spatial and spatial combined with frequency) at two feedback resolutions (low: 3 and high: 5 intervals). In both schemes, the stimulation electrodes were placed circumferentially around the upper arm. The magnitude of the normalized EMG was divided into intervals, and each electrode was associated with one interval. When the generated EMG entered one of the intervals, the associated electrode started stimulating. In the combined encoding, the additional frequency modulation of the active electrode also indicated the momentary magnitude of the signal within the interval. The results showed that combined coding decreased the undershooting rate, variability and absolute deviation when the resolution was low but not when the resolution was high, where it actually worsened the performance. This demonstrates that combined coding can improve the effectiveness of EMG feedback, but that this effect is limited by the intrinsic variability of myoelectric control. Our findings, therefore, provide important insights as well as elucidate limitations of the information encoding methods when using electrotactile stimulation to convey a feedback signal characterized by high variability (EMG biofeedback)
Aerospace medicine and biology: A continuing bibliography with indexes (supplement 344)
This bibliography lists 125 reports, articles and other documents introduced into the NASA Scientific and Technical Information System during January, 1989. Subject coverage includes: aerospace medicine and psychology, life support systems and controlled environments, safety equipment, exobiology and extraterrestrial life, and flight crew behavior and performance
Spatial-Temporal Characteristics of Multisensory Integration
abstract: We experience spatial separation and temporal asynchrony between visual and
haptic information in many virtual-reality, augmented-reality, or teleoperation systems.
Three studies were conducted to examine the spatial and temporal characteristic of
multisensory integration. Participants interacted with virtual springs using both visual and
haptic senses, and their perception of stiffness and ability to differentiate stiffness were
measured. The results revealed that a constant visual delay increased the perceived stiffness,
while a variable visual delay made participants depend more on the haptic sensations in
stiffness perception. We also found that participants judged stiffness stiffer when they
interact with virtual springs at faster speeds, and interaction speed was positively correlated
with stiffness overestimation. In addition, it has been found that participants could learn an
association between visual and haptic inputs despite the fact that they were spatially
separated, resulting in the improvement of typing performance. These results show the
limitations of Maximum-Likelihood Estimation model, suggesting that a Bayesian
inference model should be used.Dissertation/ThesisDoctoral Dissertation Human Systems Engineering 201
Aerospace medicine and biology: A continuing bibliography with indexes (supplement 359)
This bibliography lists 164 reports, articles and other documents introduced into the NASA Scientific and Technical Information System during Jan. 1992. 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
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