Development of devices for the visually impaired people equipped with a vibrating interface was the motivation of the research presented in the paper. Knowledge about discriminative ability of touch is crucial when designing devices which use tactile interfaces. The paper presents results of psychophysical studies on determining the vibrotactile frequency discrimination threshold on the wrist of blind and partially sighted people. The transformed adaptive method 1 up/2 down was used in the presented research. Thresholds were obtained on the ventral wrist at 5 frequencies: 25, 31.5, 63, 125 and 250 Hz. Results were examined to find factors which could influence the threshold value. Additionally, the guidelines for devices with vibrating interfaces supporting spatial orientation of the blind and partially sighted people was developed based on results and analysis
The paper constitutes a summary of the work carried out under the research project entitled The development of the method for marking and identi cation of the spots dangerous and of special importance for vision impaired persons in the big city with use of the wave-vibration markers. This article discusses key researches conducted during the project, including review of in uence of environmental sounds on orientation and mobility of blind and partially sighted people, results of vibration perception threshold measurement taken at the wrist of both hands, measurements of paraseismic vibrations and results of researches on annoyance, recognizability and easiness to learn of selected signals.
In this paper, we demonstrate how to reduce the noise level of expanded air from pneumatic tools. Instead of a muffler, we propose the expanded collecting system, where the air expands through the pneumatic tube and expansion collector. We have elaborated a mathematical model which illustrates the dynamics of the air flow, as well as the acoustic pressure at the end of the tube. The computational results were compared with experimental data to check the air dynamics and sound pressure. Moreover, the study presents the methodology of noise measurement generated in a pneumatic screwdriver in a quiet back room and on a window-fitting stand in a production hall. In addition, we have performed noise measurements for the pneumatic screwdriver and the pneumatic screwdriver on an industrial scale. These measurements prove the noise reduction of the pneumatic tools when the expanded collecting system is used. When the expanded collecting system was applied to the screwdriver, the measured Sound Pressure Level (SPL) decreased from 87 to 80 dB(A).
This paper presents the soundscape analysis of two settlements in Spitsbergen in Svalbard archipelago. The first one is the largest settlement in Spitsbergen, Longyearbyen, with population of about 2000 people. It is the administrative center of Svalbard with airport and the seat of Governor of Svalbard. The second one, Pyramiden, is Russian, coal-mining settlement closed in 1998. Since 2007 Pyramiden has become the tourist attraction with hotel and small museum. Only a few workers live there permanently. Two one-week research expeditions were organized to perform preliminary Arctic soundscape measurements. First, summer expedition during polar day and second winter-spring expedition during the transition period between the polar night and polar day. Long and short term sound pressure level measurements together with the ambisonic recordings of unique and typical sounds were made. Both qualitative assessment and quantitative analysis of the results were carried out. The identification and classification of the existing sound sources were conducted. Furthermore, noise maps of both places together with the comparative analysis were performed.
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