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Psychoacoustical Estimation of Selected Acoustic Signals Which Can Be Applied at Pedestrian Crosswalks

100%
Bogusz E., Furmann A.
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issue 6A
925-931
EN
The paper presents a psychoacoustical evaluation of selected acoustic signals, which according to Polish and international recommendations can be applied at pedestrian crosswalks. The aim of the study was the optimal adjustment of parameters of the signals emitted at pedestrian crosswalks, and to meet the expectations of persons with vision impairments as well as nearby residents or workers working near the crossing. The psychoacoustical evaluation of acoustic signals consists of determination of the hearing threshold of signals in the quiet, detection of signals presented against a background of various types of traffic noises (estimated signal-to-noise ratio) and annoyance assessment of signals. Three types of intermittent sounds were analysed: signals with rectangular time pattern filled up with rectangular wave, signals with rectangular time pattern filled up with sinusoidal wave and signals with triangular time pattern filled up with sinusoidal wave. Four fundamental frequencies (550 Hz, 880 Hz, 1580 Hz and 2000 Hz) and two repetition rates (5 Hz and 9 Hz) were tested. The results of the study have shown that the most suitable signals which can be applied at pedestrian crosswalks are the intermittent sounds with rectangular time pattern filled up with rectangular wave of fundamental frequencies 880 Hz and 1580 Hz and repetition rate 5 Hz and the intermittent sounds with rectangular time pattern and triangular time pattern both filled up with sinusoidal wave of fundamental frequencies 1580 Hz and repetition rate 5 Hz.
2
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Investigation of Performance in Selected Auditory Tasks by Blind and Visually Impaired Children and Teenagers

81%
Bogusz E., Koprowska H., Skrodzka E.
Acta Physica Polonica A
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2012
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vol. 121
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issue 1A
A-13-A-18
EN
The present work discusses results concerning sound perception obtained in selected auditory tasks, such as pitch discrimination and pitch-timbre categorization for blind and visually impaired subjects (children and teenagers). Listeners were divided into two age groups: 7-13 year olds and 14-18 year olds. The study tested 20 individuals (8 congenitally blind and 12 visually impaired) and 20 sighted persons comprising reference groups. The timing of the experiments was as short as possible due to the fact that our listeners were children. To date, no study has described results of such experiments for blind/visually handicapped children and teenagers. It was shown that the performance of blind/visually impaired participants was not as good as that of blind adults in pitch discrimination and pitch-timbre categorization tasks. These results may have implications for the development of auditory training in orientation and mobility of young visually handicapped people.
3
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Investigation of Vibratory Detection Thresholds on Proximal Phalange and Wrist in Blind and Visually Impaired Teenagers

81%
Bogusz E., Mrozik G., Skrodzka E.
Acta Physica Polonica A
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2012
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vol. 121
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issue 1A
A-19-A-23
EN
The paper presents results concerning vibratory detection thresholds measured on a wrist and proximal phalange and fingertips of the index, middle and ring fingers for blind and visually impaired teenagers. Subjects with vision dysfunctions were divided into two groups: congenitally blind and visually impaired. The study tested 10 handicapped individuals (5 congenitally blind and 5 visually impaired) and 10 sighted persons making reference groups chosen to be adequate in terms of age, gender, body mass and height. To date, no study has described results of such experiments for blind/visually handicapped teenagers. Vibratory perception thresholds were tracked using the Bekesy algorithm. The thresholds were investigated as a function of stimulating force frequency and magnitude or an area of a stimulating probe. Threshold values obtained for the wrist were higher than values obtained for proximal phalange and fingertips. It was shown that the performance of blind/visually impaired teenagers was not better than their sighted counterparts. Suggestions about technical form and physical parameters of a vibrating device signalling places particularly dangerous for blind/visually handicapped people were formulated.
4
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A New Method of Teaching Spatial Orientation to the Blind

37%
Hojan E., Jakubowski M., Talukder A., Wereda H., Furmann A., Ewertowski R., Skrodzka E., Perz P., Pękala P., Bogusz E., Lubawy H., Tomaszewski F., Czechyra B., Orczyk M., Szymański G., Niewiarowicz M., Hojan-Jezierska D., Jezierska A.
Acta Physica Polonica A
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2012
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vol. 121
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issue 1A
A-5-A-8
EN
Elaboration of a new method of teaching spatial orientation to blind and visually handicapped persons base on urban environment sounds was shown. Task 1 is a questionnaire inquiry on the problems of the blind moving in a big city. In Task 2 a preliminary selection and classification of the acoustic signals and vibrations that can be useful for spatial orientation was made. In Task 3 an analysis of acoustic signals for sound signalisation at pedestrian crossings was made. Some solutions for acoustic signalization were proposed. In Task 4 sounds and vibrations necessary for a library of acoustic events and situations characteristic of a city were recorded. In Task 5 the library was created and arranged to be ready to be used by teachers in the spatial orientation training. The most important outcome of the study was to develop a method of spatial orientation teaching with employment of sounds and verification of the method (Task 6). After verification it is concluded that the method is useful for spatial education of the blind at different levels of their education.
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