• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2006년도 춘계학술대회논문집
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• pp.1194-1197
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• 2006

Recently, international standard for measurement of sound absorption in a reverberation room has been amended. In the revised version, temperature, humidity and air pressure conditions are strictly restricted and also the concrete procedures are presented to reduce the differences in test results by adding inspection of diffusion, measurement uncertainty etc. In this paper, the systematic tests are conducted based on the inspection guide of diffusion defined by ISO 354 and the effects of diffusers on the measurement of sound absorption ratio are considered. As a result, we perceived that the averaged sound absorption ratio in mid and high frequency range is expected to measure around $0.05{\sim}0.1$ higher in high sound absorption material. Therefore, as for the reverberation room for measurement of sound absorption, we need to take into consideration not only the spatial standard deviation of sound pressure mandated by ISO 3741, but also, inspection regulation of diffusion showed by ISO 354.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2003년도 춘계학술대회논문집
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• pp.617-621
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• 2003

Existing loudness models are specified only to diotic sounds in spite of the fact that normal human beings hear dichotic sounds. Approximately, the arithmetic mean of loudness values of both ear signals has been suggested for the resultant perceived loudness. In this study, the dependence of overall loudness perception on the interaural level differences was investigated by the subjective tests. It was found that the larger the interaural level difference, the louder the perception than the mean of calculated loudness values at both ears and the lower the critical band rate or the reference level, the louder the perception than the mean value. A modified loudness model was proposed to he applicable to dichotic sounds by using the equivalent diotic levels.

• 대한인간공학회지
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• 제23권3호
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• pp.89-99
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• 2004

A comprehensive psychophysical scaling system, multiple-modality magnitude estimation system (MMES) has been designed to measure subjective multidimensional human perception. Unlike paper-based magnitude estimation systems, the MMES has an additional auditory peripheral cue that varies with corresponding visual magnitude. As the simplest, purely psychological case, bimodal divided-attention conditions were simulated to establish the superiority of the MMES. Subjects were given brief presentations of pairs of simultaneous stimuli consisting of visual line-lengths and auditory white-noise levels. In the visual or auditory focused-attention conditions, only the line-lengths or the noise levels perceived should be reported respectively. On the other hand, in the divided-attention conditions, both the line-lengths and the noise levels should be reported. There were no significant differences among the different attention conditions. Human performance was better when the proportion of magnitude in stimulus pairs were identically presented. The additional auditory cues in the MMES improved the correlations between the magnitude of stimuli and MMES values in the divided-attention conditions.

• 한국소음진동공학회논문집
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• 제22권7호
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• pp.605-618
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• 2012

In this study, the possibility of decision error is investigated to identify and improve the reliability of participants in the process of conducting the sound quality analysis for laser printers. So far, there is not a way to identify and express the possibility of individual participant quantitatively. Thus, the decision error model is proposed which is based on the expectation value between the perceived sounds. Through the experimental verification on the laser printers, it was found that the possibility of decision error is affected according to the normalized difference. The possibility of decision error has inversely proportional to the normalized difference between the perceived sounds. When the normalized difference becomes small value, the uncertainly between decisions is inversely increase, and then it is difficult to obtain the proper result in the process of the jury evaluation for laser printers. For this reason, in this study, the proposed decision error model is added in the previous step of the correlation verification. Comparing to the conventional process only using the correlation based method, after the reliability of each participant is verified, the correlation with the mean response of participants is verified. It was found that the participants who were recognized as having unusual preferences are actually identified as having the reliability problem. Based on the results of this study, the proposed decision error model will be helpful to identify and improve the reliability of participants in the following study for the sound quality analysis.

• 인지과학
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• 제27권1호
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• pp.129-157
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• 2016

본 연구는 한국어의 소음속말인지(Speech perception in noise, SPIN)에 대하여 알아 보았다. 영어의 SPIN 테스트와 비슷한 형식을 채택하여 새로운 한국어 SPIN 테스트를 개발하였다. 예측성 효과와 소음효과, 이 둘의 상호작용에 대하여 알아봄으로써 기존의 영어에 기반을 둔 연구에서 발견한 것들을 재확인하고자 하였다. 새로운 한국어 SPIN 테스트를 사용하여 14명의 성인 한국인을 대상으로 한 실험 결과는 이전 연구들이 발견한 사항들을 다시 한 번 입증하였다. 첫째, 참여자들의 대체적인 SPIN 수행능력은 상대적으로 고소음 보다 저소음환경에서 더 나았다. 둘째, 문맥상 비교적 예측하기 쉬운 단어들이 예측하기 어려운 단어들보다 특히 고소음 환경에서 더 정확히 인지되었다. 이러한 결과는 청자들이 두 가지 종류의 정보, 즉 음성적 정보와 문맥적 정보를 말인지에 적극적으로 사용한다는 것을 의미하는 것으로 해석할 수 있다. 소음으로 인해서 말소리의 음성적인 특징이 약해졌을 때 청자들은 말소리를 처리하기 위해서 언어적 문맥정보를 적극적으로 이용하는 것이다. 본 연구에서 발견한 것들은 영어의 SPIN 테스트에 기반을 둔 기존 연구들에서 발견한 것과 일치한다. 게다가, 표적어의 빈도 효과에 대한 가능성을 발견하였는데, 이는 한국어의 이 분야에 대한 더 다양하고 활발한 연구가 있어야 함을 시사한다.

• Industrial Engineering and Management Systems
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• 제13권2호
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• pp.172-184
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• 2014

Economic growth with rising household income has put more vehicles on the roads worsening traffic congestion, road accidents, and air and noise pollution. This situation is further aggravated by the potential working population who choose to drive to work instead of taking public transportation. Public bus transport (PBT) plays an important role in alleviating these problems. PBT is underutilized in Malaysia, and there is an opportunity to increase ridership without substantial investment. Therefore, this study was conducted to investigate the factors that influence the use of PBT in Malaysia. The data were collected using structured questionnaires from 400 respondents. The results of the analysis show that the twin factors consisting of perceived satisfaction of and perceived importance by users towards safety and comfort of facilities and services offered by PBT are significantly related to intention to use those services. The satisfaction of availability of season tickets, the importance of reliability of bus schedule and time table, and the importance of ticket pricing are also significant. By providing insights for both public bus operators and the government, this paper contributes to mitigate the underutilization of PBT in Malaysia and the consequences of putting more vehicles on the roads. From the theory perspective, this paper also contributes by extending the theory of reasoned-action to transportation studies.

• Journal of Information Processing Systems
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• 제15권3호
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• pp.604-615
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• 2019

Single-user spectrum sensing is susceptible to multipath effects, shadow effects, hidden terminals and other unfavorable factors, leading to misjudgment of perceived results. In order to increase the detection accuracy and reduce spectrum sensing cost, we propose an adaptive cooperative sensing strategy based on an estimated signal-to-noise ratio (SNR). Which can adaptive select different sensing strategy during the local sensing phase. When the estimated SNR is higher than the selection threshold, adaptive double threshold energy detector (ED) is implemented, otherwise cyclostationary feature detector is performed. Due to the fact that only a better sensing strategy is implemented in a period, the detection accuracy is improved under the condition of low SNR with low complexity. The local sensing node transmits the perceived results through the control channel to the fusion center (FC), and uses voting rule to make the hard decision. Thus the transmission bandwidth is effectively saved. Simulation results show that the proposed scheme can effectively improve the system detection probability, shorten the average sensing time, and has better robustness without largely increasing the costs of sensing system.

• 한국항해항만학회지
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• 제43권2호
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• pp.110-121
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• 2019

Ports play a key role in international trade, as integral hubs where passengers and cargoes are loaded, discharged, and transshipped. However, the function of ports is becoming more diversified, expanding on roles as industrial clusters, as well as logistical centers. Such roles combined, reap numerous and significant benefits, mainly with growth of jobs and wealth creation, for the local population living in the city, and beyond. Citizens' awareness of the function and value of ports may not be positive, because of a range of negative factors such as emissions, noise, and road congestion, which can influence their perception. This study's contribution focuses on empirically evaluating the perception of Busan citizens of the local port, by applying Q methodology. The links connecting the port-city and local population, are assessed by identifying: 1) The level of awareness of the Busan citizens of the port; 2) Factors perceived as positive as well as factors perceived as negative by Busan citizens. There are four main factors, derived from the analysis: 1) Port functional knowledge; 2) Lack of social connectedness port-city; 3) Environmentally concerned and; 4) Absent port's ripple's effect. Policy recommendations suggest focusing on improving citizens' perception of the port, for each of the four main factors derived from the analysis.

• 한국소음진동공학회논문집
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• 제27권1호
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• pp.14-19
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• 2017

Fuel oil consumption cost varies depending on every ship operation and this roughly amounts to 70 % of shipping companies' total revenue. As such, efforts towards improved fuel economy are being pursued. An annual 1 % reduction in fuel consumption is perceived to result in saving tens million US dollars on the global fleet operation. One approach is the application of power take-off configurations which are seen to increase fuel oil economy and are suitable for power generation. In this study, the dynamic properties of a shaft generator coupled on a 10S90ME main engine of an 18 600 TEU container vessel is presented. The vibratory torque and angular velocity variation was examined through theoretical analysis and actual vibration measurement. The result of the study suggests a review on existing classification rules for generator design and the lowering of vibratory torque and angular velocity variation guideline.

• 한국주거학회논문집
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• 제24권6호
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• pp.189-197
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• 2013

The purpose of the study was to analyze the improvement elements depended on housing quality measurement tool related to mental health. The data for the analysis was collected through questionnaire survey method from November 1, 2012 to January 17, 2013, and the sample consisted of 720 respondents living in single detached houses, multi-families detached houses, apartments, and town houses in 4 cities, Seoul, Busan, Daejeon, and Kwangju. The data were analyzed using descriptive statistics. The results of improvement elements are as follows: 1) Pedestrian-threaten street from cars in physical safety 2) A secluded or dark spot and fear of walking at night in social security, 3) Indoor noise, outdoor noise, and evidence of abandoned trash heap/bottle in neighborhood in health & sanitation, 4) Illegal parking and heating control system in facility convenience, 5) Extra kitchen, number of bathrooms, and community spaces in space convenience, 6) Openness and spaciousness of indoor room, and satisfaction of house and neighborhood in comfort, 7) Management common/sharing space in maintenance, 8) Energy saving facility and environment friendly materials use in sustainability, 9) Burden on housing cost, asset value on house, and school district in economic value, 10) Reflection of residents style, surrounding building's number of layers, and neighborhood appearance of preference in housing environment image.