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Tactual perception of liquid material properties
No full textIn this paper, studies into the tactual perception of two liquid material properties, viscosity and wetness, are reviewed. These properties are very relevant in the context of interaction with liquids, both real, such as cosmetics or food products, and simulated, as in virtual reality or teleoperation. Both properties have been the subject of psychophysical characterisation in terms of magnitude estimation experiments and discrimination experiments, which are discussed. For viscosity, both oral and manual perception is discussed, as well as the perception of the viscosity of a mechanical system. For wetness, the relevant cues are identified and factors affecting perception are discussed. Finally, some conclusions are drawn pertaining to both properties
Haptic perception of force
No full textThis chapter reviews research that deals with measuring the precision and/or the accuracy of haptic force perception, using psychophysical methods. Other aspects of force perception might include physiological aspects or neuronal processing, but these are beyond the scope of the present article. Furthermore, force sensation plays a role in the perception of other physical aspects, such as friction or stiffness. These aspects are reviewed separately This chapter reviews research that deals with measuring the precision and/or the accuracy of haptic force perception, using psychophysical methods. Other aspects of force perception might include physiological aspects or neuronal processing, but these are beyond the scope of the present article. Furthermore, force sensation plays a role in the perception of other physical aspects, such as friction or stiffness. These aspects are reviewed separatel
Improving the Prediction of Haptic Impression User Ratings Using Perception-Based Weighting Methods: Experimental Evaluation
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Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Tactual perception of material properties
No full textAbstractThis paper reviews tactual perception of material properties such as roughness, compliance, coldness and friction. Psychophysical functions relating physical properties to perception are discussed, as well as discrimination thresholds. Also, the neural codes mediating some of these sensations are discussed. Furthermore, we take a look into how sensation of these material properties can be induced artificially in haptic displays. Lastly, the interactions between perception of the different material properties are explored
Seeing and feeling size: a cross-modal discrimination experiment
No full textHow does the size of an object that you can only see compare to that of an object you can only feel? To answer this question we have conducted an experiment where participants verbally reported which of the following they perceived as being larger: a visually presented object that could not be touched or a haptically presented object that could not be seen. Haptic exploration was either unrestricted or the object was presented on a stand, thereby removing mass information. Participants were tested in a 2 (exploration) × 2 (shape) within-subject design where each block consisted of a single condition. Within each block, 4 staircases of 20 trials were presented interleaved. Stimuli ranging in size between 2-10 cm³ and 6-14 cm³ were tested against reference volumes of 6 and 10 cm³, respectively (both haptically and visually). The perceptual bias results from subtracting the reference volume from the point of subjective equality. Data from 12 participants show that they are consistent in their judgments within a block. However, it seems that substantial variances arise between blocks and between participants but independent of shape or exploration type. These results suggest that judgment is recalibrated at the start of each block
Discrimination of thermal diffusivity
No full textMaterials such as wood or metal which are at equal temperatures are perceived to be of different 'coldness' due to differences in thermal properties, such as the thermal diffusivity. The thermal diffusivity of a material is a parameter that controls the rate with which heat is extracted from the hand when it touches an object of that material. This rate of heat extraction is an important cue for distinguishing materials and recognising objects by means of touch. We have measured the ability of human observers to discriminate between different rates of heat extraction. This was done using a device that displayed different transient temperature profiles to the finger. In different conditions, subjects were repeatedly asked to select the faster-cooling of two stimuli. The discrimination threshold was around 43% of the extraction rate. A rate that was twice as slow also yielded twice the absolute discrimination threshold. When we halved the temperature difference between beginning and end of the stimulus, the threshold did not change as much. This shows that subjects can use the rate of heat extraction as a cue and that they can discriminate between materials if their thermal diffusivities are at least 43% apart
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