• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.11a
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• pp.177-182
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• 2003

This study is directed toward determining the number and characteristics of psychologically meaningful perceptual dimensions required for assessing the sound Ouaiity with respect to vehicle interior and/or exterior noises. and toward identifying the acoustical or psychoacoustical bases underlying the perception. By nonmetric MDS and clustring analysis of sound quality data sets on our own, of critical importance are two perceptual dimensions for which subjective verdicts can be interpreted as loudness and sharpness. The perceptual dimensions based upon similarity judgments could be accounted for 48% and 24% of the variance. each of which might be a match for the acoustic parameter "A-weighted maximum pressure level"(r= .85) and for the psychoacoustic parameter "sharpness" (r= .65), respectively. On the other hand, the perceptual dimensions based upon preference ratings could explain 66% and 10% of the variance. where the acoustic parameter "A-weighted maximum pressure leve"(r= .92) might be taken to be a best predictor, but sharpness appeared to be less suitable for the description of Preference behavior. Linked to the results, the problems of quantitative modelling of subjective sound quality evaluation and also of implementing corresponding cognitive combination rule for technical and industrial applications, say having "winner-sound qualify" according to preference criteria will be shortly in discussion.

• Korean Journal of Environmental Biology
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• v.40 no.2
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• pp.172-186
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• 2022

Benthic macroinvertebrates are important ecological and environmental indicators as primary or secondary consumers, and therefore are widely used in the evaluation of aquatic environments. However, there are no comprehensive river ecosystem monitoring surveys that link the major physicochemical water quality items with benthic macroinvertebrates in urban streams. Therefore, this study investigated the distribution characteristics of benthic macroinvertebrates and physicochemical water quality items (17 items) in Yangjaecheon and Yeouicheon from 2019 to 2020. At the same time, by applying Spearman's rank correlation analysis and nonmetric multidimensional scaling (nMDS) analysis in the water quality data and biotic index, we tried to provide basic data for diagnosing the current status of river ecosystems in major urban rivers in Seoul. Based on the study results, a total of 39 species and 3,787 individuals were identified in Yangjaecheon, the water quality(based on BOD, TOC, and TP) of Yangjaecheon was higher than Grade Ib(good), and the BMI using benthic macroinvertebrates appeared as Grade C(normal) at all the sites. In Yeouicheon, a total of 51 species and 4,199 individuals were identified, the water quality(based on BOD, TOC, TP) was higher than Grade Ib(good) similar to Yangjaecheon, and the BMI of both Upstream and Saewon bridge was Grade B(good), while Yeoui bridge was Grade C(normal). Overall, analysis results for the distribution of benthic macroinvertebrates by a nonmetric multidimensional scaling method showed no significant difference between the two streams (p=0.1491). Also, significant environmental variables related to benthic macroinvertebrates distribution were determined as water temperature and DO. On the other hand, the results of the correlation analysis between biotic index and major water quality items confirmed that R1 and BMI could be used for on-site urban river water quality evaluation.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.14 no.12
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• pp.1223-1232
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• 2004

This study is directed toward determining the number and characteristics of psychologically meaningful perceptual dimensions required for assessing the sound quality with respect to vehicle noises, and toward identifying the acoustical and/or psychoacoustical bases underlying the preference and similarity judgments. For the purpose of analyzing the paired comparison data produced by subjective ratings we used nonmetric multidimensional scaling(MDS). The perceptual dimensions based upon preference ratings could explain 76.3 % of the variance by maximum dB(A) and sharpness acum. The correlation between objective and subjective positions of the stimuli is $R^2$=0.97(F(1,13)=195.45, p < .01), corrected $R^2$=0.93. The less the intensity of the stimulus the more becomes the subjective Position would be over-estimated relative to the objective one. The same is valid for the opposite case. The perceptual dimensions based upon similarity judgments could be accounted for 47.8 % and 23.5% of the variance, each of which might be a match for the maximum dB(A) and the sharpness acum, respectively. The correlation between objective and subjective positions of the stimuli is $R^2$=0.94(F(1,13)=92.38, p < .01), corrected $R^2$=0.87. The more the intensity of the stimulus the more becomes the subjective position would be over-estimated relative to the objective one. The same is valid for the opposite case. In other words, it is likely that the larger the amount of two stimuli which to compare would be judged similar. So far it should be further clarified that whether the relationship between preference ratings and psychological distances nay be optimized through which psycho-physical models.