Schedule in October 2014
The 18th Perceptual Frontier Seminar: Real Virtuality
Date and time: Wednesday, 15 October 2014, from 16:50 to 19:00
After the Seminar, we will go out for dinner.
1. Neural substrates of perceptual equality/inequality of two neighboring time intervals: an EEG study
Brain activity related to time estimation processes in humans was analyzed using a perceptual phenomenon called auditory temporal assimilation. Two ERP experiments showed that slow negative component (SNCt) appears in the right-frontal brain area (around the F8 electrode) after the presentation of the stimulus, which is associated with judgment of the equality/inequality of two neighboring time intervals(T1 and T2). The magnitude of SNCt was larger for the temporal patterns causing perceptual inequality than those for perceptual equality, suggesting that the SNCt can be a signature of equality/inequality judgment, which derives from the comparison of T1 and T2.
2. Afterimage and aftereffect
After viewing a visual object with steady fixation, we see its afterimage in the complementary colors on a blank screen. Recent studies have shown that an afterimage is not a simple trace on the retina. In this talk, we will introduce some of our research results on this topic, including perceptual shape changes, perceptual decomposition of a pattern, and motion aftereffect appearing in afterimages.
3. Intelligibility of Japanese speech is preserved fairly well by four power-fluctuation factors: A new method of factor analysis
An improved method of factor analysis was developed to analyze and resynthesize power fluctuations of speech signals in 20 critical-band filters. Spoken sentences of British English, Japanese, and Mandarin Chinese were analyzed with this method, and the number of derived factors was varied from 1 to 9; 3 or 4 factors turned out to represent a common tendency across these languages. Power fluctuations were resynthesized from the obtained factor loadings and factor scores for Japanese speech in order to generate noise-vocoded speech for a listening test. The noise-vocoded speech signals obtained from the 4-factor analysis were fairly intelligible; 9 listeners identified 88% of the morae correctly on average.
4. An introduction to the human-oriented interface design of a computer
Designing the interfaces of computers in a human-oriented way is of vital importance, if the computers are to be accepted in our daily life. Three examples will be presented to show how the computers with human-oriented interfaces were realized: a human behavior monitoring system utilizing an electronic conductive textile, a life-log interface and a case study of its practical application, and a haptic massage device that works as an interface utilizing haptic illusion and at the same time, a device of reflexology.
5. Introduction of Nitto and technologies for noise and vibration
Noise and vibration reduction technologies play a significant role in designing damping and acoustic related materials for various kinds of fields such as automobiles, railways, electrical appliances, etc. In order to develop a more advanced product, not only material design technologies but also systematic evaluation technologies corresponding human feeling are required. Such systematic sensory evaluation can contribute to enhancing comfortable feeling by means of the noise and vibration technologies when the product being applied.