Experimental investigation on thermal comfort model between local thermal sensation and overall thermal sensation

To study the human local and overall thermal sensations, a series of experiments under various conditions were carried out in a climate control chamber. The adopted analysis method considered the effect of the weight coefficient of local average skin temperature and density of the cold receptors’ distribution in different local body areas. The results demonstrated that the thermal sensation of head, chest, back and hands is warmer than overall thermal sensation. The mean thermal sensation votes of those local areas were more densely distributed. In addition, the thermal sensation of arms, tight and calf was colder than the overall thermal sensation, which pronounced that thermal sensation votes were more dispersed. The thermal sensation of chest and back had a strong linear correlation with overall thermal sensation. Considering the actual scope of air-conditioning regulation, the human body was classified into three local parts: a) head, b) upper part of body and c) lower part of body. The prediction model of both the three-part thermal sensation and overall thermal sensation was developed. Weight coefficients were 0.21, 0.60 and 0.19 respectively. The model provides scientist basis for guiding the sage installation place of the personal ventilation system to achieve efficient energy use

Exploring How Haptics Contributes to Immersion in Virtual Reality

Virtual Reality (VR) has been around for more than fifty years but the technology hasn’t reached practical usability until very recently. With the current head-mounted display (HMD) technology and an abundance of investment in VR startups, we have finally reached at the point where it is possible to simulate complex virtual environments that feel immersive. A major problem with virtual reality is that everything looks real but you can not touch and feel virtual objects. We are focusing on developing a device that will allow users to feel what they touch in VR. We developed a hand-held interface and an android app as a test environment. Commercially-available solutions such as the leap motion developer’s kit were used to track the position of a user’s hand. The actual touch sensation was delivered by a broad-band actuator. Informal testing suggests that being able to feel a virtual object, such as a virtual football, in the hands can enhance user immersion, enjoyment and performance in VR. Future work will improve hand tracking accuracy and range of touch sensations for a more realistic user experience

Layer Edge States Stabilized by Internal Electric Fields in Two-dimensional Hybrid Perovskites

Two-dimensional (2D) organic-inorganic hybrid perovskites have been intensively explored for recent years, due to their tunable band gaps and exciton binding energies, and increased stability with respect to three-dimensional (3D) hybrid perovskites. There were fascinating experimental observations suggesting the existence of localized edge states in 2D hybrid perovskites which facilitate extremely efficient electron-hole dissociation and long carrier lifetimes. The observations and explanations of the edge states are not quite converging implying that there can be multiple origins for the edge state formation. Using first principles calculations, we demonstrate that layer edge states are stabilized by internal electric fields created by polarized molecular alignment of organic cations in 2D hybrid perovskites when they are two layers or thicker. Our study gives a simple physical explanation of the edge state formation, and it will pave the way for designing and manipulating layer edge states for optoelectronic applications

Manual discrimination of force

Optimal design of human-machine interfaces for teleoperators and virtual-environment systems which involve the tactual and kinesthetic modalities requires knowledge of the human's resolving power in these modalities. The resolution of the interface should be appropriately matched to that of the human operator. We report some preliminary results on the ability of the human hand to distinguish small differences in force under a variety of conditions. Experiments were conducted on force discrimination with the thumb pushing an interface that exerts a constant force over the pushing distance and the index finger pressing against a fixed support. The dependence of the sensitivity index d' on force increment can be fit by a straight line through the origin and the just-noticeable difference (JND) in force can thus be described by the inverse of the slope of this line. The receiver operating characteristic (ROC) was measured by varying the a priori probabilities of the two alternatives, reference force and reference force plus an increment, in one-interval, two-alternative, forced-choice experiments. When plotted on normal deviate coordinates, the ROC's were roughly straight lines of unit slope, thus supporting the assumption of equal-variance normal distributions and the use of the conventional d' measure. The JND was roughly 6-8 percent for reference force ranging from 2.5 to 10 newtons, pushing distance from 5 to 30 mm, and initial finger-span from 45 to 125 mm. Also, the JND remained the same when the subjects were instructed to change the average speed of pushing from 23 to 153 mm/sec. The pushing was terminated by reaching either a wall or a well, and the JND's were essentially the same in both cases

Effect of Information Content in Sensory Feedback on Typing Performance using a Flat Keyboard

Abstract-We investigate the effect of information content in sensory feedback on typing performance using a flat keyboard. We build a flat keyboard apparatus with haptic and auditory keyclick feedback. We evaluate and compare typing performance with key-press confirmation and key-correctness information through sensory feedback. Twelve participants are asked to touch-type a number of randomly selected phrases under various combinations of visual, auditory and haptic sensory feedback conditions. The results show that typing speed is not significantly affected by the information content in sensory feedback, but the uncorrected error rate is significantly lower when key-correctness information is available. The results also show that key-correctness information leads to more corrected errors and lowers typing efficiency. Our findings are useful for developing flat keyboards with assistive information through sensory feedback. Our study is the first step towards improving typing performance on flat keyboards by delivering more advanced and comprehensive assistive information beyond the visual channel

Creating Embedded Haptic Waveguides in a 3D-Printed Surface to Improve Haptic Mediation for Surface-based Interaction

acceptedVersionPeer reviewe

Spatiotemporal Integration in Somatosensory Perception: Effects of Sensory Saltation on Pointing at Perceived Positions on the Body Surface

In the past, sensory saltation phenomena (Geldard and Sherrick, 1972) have been used repeatedly to analyze the spatiotemporal integration capacity of somatosensory and other sensory mechanisms by means of their psychophysical characteristic. The core phenomenon consists in a systematic mislocalization of one tactile stimulus (the attractee) toward another successive tactile stimulus (the attractant) presented at another location, increasing with shorter intervals. In a series of four experiments, sensory saltation characteristics were studied at the forearm and the abdomen. Participants reported the perceived positions of attractees, attractants, and reference stimuli by pointing. In general, saltation characteristics compared well to those reported in previous studies, but we were able to gain several new insights regarding this phenomenon: (a) the attractee–attractant interval did not exclusively affect the perceived attractee position, but also the perceived attractant position; (b) saltation characteristics were very similar at different body sites and orientations, but did show differences suggesting anisotropy (direction-dependency) in the underlying integration processes; (c) sensory saltation could be elicited with stimulation patterns crossing the body midline on the abdomen. In addition to the saltation-specific results, our experiments demonstrate that pointing reports of perceived positions on the body surface generally show pronounced systematic biases compared to veridical positions, moderate intraindividual consistency, and a high degree of inter-individual variability. Finally, we address methodological and terminological controversies concerning the sensory saltation paradigm and discuss its possible neurophysiological basis

A Study of the Affordance of Haptic Stimuli in a Simulated Haunted House

The present study investigates the affordance of vibrotactile signals in a simulated haunted house. Participants experienced a virtuals´eance using a head-mounted display, sound, and haptic stimuli on the palm and thighs.acceptedVersionPeer reviewe