• 한국통신학회논문지
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• 제36권4B호
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• pp.314-321
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• 2011

영상 품질의 주관적 측정을 위한 다양한 표준 방법들이 제시되었으나, 이들 방법들은 원본 기준 영상이 존재하는 환경에서 10초 내외의 짧은 시간의 시청을 기반으로 한다. 그러나, IPTV 시청 환경에서는 장시간의 시청(예를들어 30분이상)이 이루어지므로, 표준 방법들에서의 10초 시간 주기의 평가는 현실적으로 적절하지 못하다. 본 논문에서는 IPTV 제공 환경에서 주관적 화질 평가를 위하여, 평가 주기 변화가 MOS에 미치는 영향을 분석하고 IPTV의 주관적 화질 평가에 적합한 평가 주기를 선정하기 위한 방안을 제시한다.

• 산업경영시스템학회지
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• 제24권65호
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• pp.65-73
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• 2001

In this study, psychophysiological stress was quantitatively evaluated at various car interior noise levels by using Electroencephalogram(EEG). An experiment was performed to investigate the most comfortable range of noise level during simulated driving condition. Twelve healthy volunteers participated in the experiment. They were asked to operate the driving simulator while six levels of interior noise were given, such as 45dB(A), 50dB(A), 55dB(A), 60dB(A), 70dB(A), 80dB(A), and maximal subjective noise level. EEG signals were recorded for 60 seconds in each noise level. The power spectral analysis was performed to analyze EEG signal. At the same time, psychological stress was also measured subjectively by using a magnitude estimation method. The results showed that subjective stress and EEG spectrum indicated a statistically significant difference between noise levels. In particular, high level noise produced an increase in beta power at temporal(T3, T4) areas. It was also found that beta activity was highly correlated with subjective perception of discomfort, and subjects responded to car interior noise as arousing or negative stimuli. Moreover, beta power remained stable above 70dB(A), whereas subjective discomfort continued to increase even above 70dB(A) We concluded that brain waves could provide psychophysiological information of drivers emotional reaction to car interior noise. Thus, EEG parameters could be a new measure to determine optimal noise level in ergonomic workplace design after further verification in various experimental conditions.

• 보건행정학회지
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• 제31권4호
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• pp.531-543
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• 2021

Background: Population aging is a serious problem in Korea. And we have experienced a rapid increase in the health expenditures of the elderly. The purpose of this paper is to analyze the effect of having a usual source of care (USC) for the elderly. Methods: This study used the Korea Health Panel Survey data of 2012, 2013, 2016, 2017, and 2018. The sample was the person who answered the USC questions among the elderly. The panel logit model was used to analyze the determinants of having USC and the panel simultaneous equation model was used to analyze the effect of having USC among the elderly on the medical expenses, medical utilization, and subjective health status. Results: The estimation result shows that age, income, marriage, and so forth turn out to be the factors of having USC. Having the clinic level USC is estimated to reduce the health care utilization and the health expenditure and to improve the subjective health status. Conclusion: It is expected that the result of our analysis will provide evidence for encouraging having USC.

• The Journal of the Acoustical Society of Korea
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• 제22권2E호
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• pp.87-92
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• 2003

In this paper, a new speech enhancement method using level adapted wavelet packet is presented. First, we propose a level adapted wavelet packet to alleviate a drawback of the conventional node adapted one in noisy environment. Next, we suggest an adaptive noise estimation method at each node on level adapted wavelet packet tree. Then, for more accurate noise component subtraction, we propose a new estimation method of spectral subtraction weight. Finally, we present a modified spectral subtraction method. The proposed method is evaluated on various noise conditions: speech babble noise, F-l6 cockpit noise, factory noise, pink noise, and Volvo car interior noise. For an objective evaluation, the SNR test was performed. Also, spectrogram test and a very simple listening test as a subjective evaluation were performed.

• 한국감성과학회:학술대회논문집
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• 한국감성과학회 2008년도 추계학술대회
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• pp.143-146
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• 2008

The objectives of this study were to evaluate color sensation for yellowish natural dye fabrics using magnitude estimation to determine physical colorimetric factors significantly related to human sensibility by establishing power function in psychophysical analysis. Fourteen different yellowish fabrics dyed with natural colorants were selected as stimuli and subjective color sensations including brightness, heaviness, softness, strength, warmth, activeness, classicalness, femininity, and pleasantness for each stimulus were evaluated. As results, yellowish natural dye fabrics in general seemed to evoke feeling of brightness, femininity, and pleasantness more strongly than that of heaviness and classicalness. Most of color sensation were significantly related with more than one of physical color properties, which leads to establishing reliable power functions between them. In the power functions, these relationships could be utilized to design color-sensible natural dye textiles.

• 한국소음진동공학회논문집
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• 제21권5호
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• pp.400-407
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• 2011

The suggested method of previous Son's study dichotomized subjective response data to modeling noise exposure-response. The method used maximum liklihood estimation instead of least square estimation and the noise exposure-response curve of the study was logistic regression analysis result. The method was originated to modeling community response rate such as %HA or %A. It can be useful when the subjective response was investigated based on predicted noise level. It is difficult to measure the single source emitting noise such as railway because various traffic noise sources combined in our life. The suggested method was adopted to model in this study and railway noise-exposure response curves were modeled because the noise level of this area was predicted data. The data of this study was used by previous Ko's paper but he dealt the area as combined noise area and divided the data by dominant noise source. But this study used all data of this area because the annoyance response to railway noise was higher than other noise according to the result of correlation analysis. The trend of the %HA and %A prediction model to train noise of this study is almost same as the model based on measured noise of previous Lim's study although the investigated areas and methods were different.

• International Journal of Internet, Broadcasting and Communication
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• 제13권1호
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• pp.161-167
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• 2021

This paper proposes a new personalized HRTF estimation method which is based on a deep neural network (DNN) model and improved elevation reproduction using a notch filter. In the previous study, a DNN model was proposed that estimates the magnitude of HRTF by using anthropometric measurements [1]. However, since this method uses zero-phase without estimating the phase, it causes the internalization (i.e., the inside-the-head localization) of sound when listening the spatial sound. We devise a method to estimate both the magnitude and phase of HRTF based on the DNN model. Personalized HRIR was estimated using the anthropometric measurements including detailed data of the head, torso, shoulders and ears as inputs for the DNN model. After that, the estimated HRIR was filtered with an appropriate notch filter to improve elevation reproduction. In order to evaluate the performance, both of the objective and subjective evaluations are conducted. For the objective evaluation, the root mean square error (RMSE) and the log spectral distance (LSD) between the reference HRTF and the estimated HRTF are measured. For subjective evaluation, the MUSHRA test and preference test are conducted. As a result, the proposed method can make listeners experience more immersive audio than the previous methods.

• 조명전기설비학회논문지
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• 제21권10호
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• pp.13-21
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• 2007

측정 결과와 분석을 바탕으로 전조등 밝기변화의 한계값과 운전자의 안전성을 고려한 평가 알고리즘을 개발하였다. 심리 평가에 의한 전조등 밝기변화의 한계값은 주관적 평가를 토대로 밝기 변화, 눈 깜박임, 불쾌감 등에 대한 값을 제시하였고, 또한, 시인성 측정에 의한 한계값은 차량을 장애물의 위협 없이 안전하게 정지하기 위한 한계값을 제시하였다.

• 대한인간공학회지
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• 제12권2호
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• pp.3-13
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• 1993

A psychophysical measurement technique called "magnitude estimation" was used to evaluate several interior design alternatives for a high speed train. Pas- senger activity, seat direction, and passenger age were manipulated by using a three factor within-subjects experimental design. During the experiment, two dependent measures, a line length and a numerical estimate for each alternative design were collected to validate the experimental procedures. The results showed that pasnger seats arranged in the same direction as the running direction of the train was favored nine times more than the opposite. Also, the subjects preferred listening to music in a coach train to the other activities such as reading newspaper, watching a movie, and resting. This paper demonstrates that a psychophysical technique can be sued in the design of a development process, especially when it is difficult to quantify design variables such as subjective opinion or preference, etc.

• 응용통계연구
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• 제13권2호
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• pp.329-341
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• 2000

한국의 농업에서 쌀 생산량조사는 매우 중요한 조사로 알려져 있다. 특히 쌀 예상 생산량조사는 농업정책결정과 관련하여 유용한 기초자료를 제공한다는 점에서 가능한 한 정확한 예측을 필요로 한다. 본 논문에서는 통계적 모형을 이용한 쌀 예상 추정방법을 제안하고 기존의 주관적 추정방법인 달관추정과 비교함으로써 쌀 예상 생산량 추정과정 통계적방법의 응용 가능성과 타당성을 제시하고 있다.