• Environmental and Resource Economics Review
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• v.23 no.2
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• pp.331-347
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• 2014

The purpose of this study is to estimate the economic value of the recreational sea fishing in the Yellow Sea using count data model. For estimating consumer surplus, we used several count data model of travel cost recreation demand such as a poisson model(PM), a negative binomial model(NBM), a truncated poisson model(TPM), and a truncated negative binomial model(TNBM). Model results show that there is no exist the over-dispersion problem and a NBM was statistically more suitable than the other models. All parameters estimated are statistically significant and theoretically valid. The NBM was applied to estimate the travel demand and consumer surplus. The consumer surplus pre trip was estimated to be 254,453won, total consumer surplus per person and per year 1,536,896won.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.8
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• pp.5413-5421
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• 2015

The aim of this study was to identify the influences of sleep quality, depression and fatigue on job stress of geriatric hospital workers. The subjects were 175 workers from 6 geriatric hospitals. Data were collected on March, 2015 using a structured questionnaire. The data were analyzed by using SPSS/WIN 21.0 program. The job stress was negatively correlated with sleep quality(r=-.364, p<.001), positively correlated with depression(r=.376, p<.001) and fatigue(r=.646, p<.001). The multiple regression analysis revealed that the most powerful predictor of job stress was fatigue(${\beta}=.581$, p<.001). These results indicate that fatigue affect job stress of the geriatric hospital workers. Therefore, it is necessary to prepare tailored fatigue management program and working conditions that can reduce job stress.

• The Journal of the Acoustical Society of Korea
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• v.24 no.3
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• pp.178-185
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• 2005

This paper presents a new music identification method using probabilistic and dynamic characteristics of melody. The propo3ed method uses pitch and MFCC parameters as feature vectors for the characteristics of music notes and represents melody pattern by pitch histogram and temporal sequence of codeword indices. We also propose a new pattern matching method for the hybrid method. We have tested the proposed algorithm in small (drama OST) and broad (1.005 popular songs) search spaces. The experimental results on search areas of OST and 1,005 popular songs showed better performance of the proposed method over conventional methods. We achieved the performance improvement of average $9.9\%$ and $10.2\%$ in error reduction rate on each search area.

• The Journal of the Acoustical Society of Korea
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• v.33 no.3
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• pp.174-183
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• 2014

When a active sonar signal is transmitted and returned back from a target, it has been distorted by various properties of acoustic channel such as multipath arrivals. And signals have been appeared to be different form by target position and attitude. Therefore, we simulated the target echo signal using 3 dimensional target model include reflects target features. In this paper, we develop components form of a simulated target model is made up equally spaced highlight points, and each part of the target consists of shape function. We can simulate a target echo signal and Target strength (TS) according to wave incident angle. To verify, we made small scale target in kit form and we had got underwater target signal for comparing simulation result in water tank.

• Environmental and Resource Economics Review
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• v.12 no.3
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• pp.469-485
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• 2003

This paper reports on the results of epidemiological investigation of daily health effects in the elderly associated with daily exposure to particulate matters in Korea. Our main focus is on the potential difference in health effects between PM10 and PM2.5. While the Korean environmental authority has set an ambient standard for PM10, the government currently does not monitor PM2.5, which has no national standard. A daily data on respiratory symptoms as well as PM concentrations are collected for a total of 120 days. Using a probit model, we find statistically significant negative health effects of PM2.5 on respiratory symptoms among the nonsmoking elderly, while PM10 does not show such effects from the estimation. This result suggests that, for air quality regulatory purposes, PM2.5 can be a more appropriate air pollutant than PM10.

• Environmental and Resource Economics Review
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• v.29 no.2
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• pp.171-194
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• 2020

We revisit the impact of oil shocks on the Korean economy and examine how this impact varies depending on a business cycle. First, we estimate the probability of a recession through a logistic probability distribution, and correct the probability to match business cycles announced by the Korea National Statistical Office. We set up a STVAR model to analyze the response of macroeconomic variables to oil shocks according to business cycles. We find that oil shocks during the recession have a negative effect on GDP in the mid- and long-term, but during the expansion, GDP does not show a statistically significant response to oil shocks. We presume that this finding is associated with the factors of both the increase in demand for consumption and the increase in current account during the economic boom. Also, we find that the impact of oil shocks on the price level was also observed differently in terms of the persistence of inflation by business cycle. These results highlight the importance of an application of a regime switching model, which has been widely used in energy economics in recent years.

• Journal of Korean Society of Forest Science
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• v.80 no.1
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• pp.20-31
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• 1991

To improve the understanding and predicting power of littering behavior in natural recreation areas, a model was proposed based on the theory of reasoned action by Fishbein and Ajzen. Among the visitors of Kaeryongsan National Park in Korea, three hundred and ninety nine (399) groups were interviewed to obtain such data as beliefs about the behavioral consequences, attitudes, normative belief, socioeconomic status and etc. A significant but practically weak relationship was found between beliefs, normative belief and past behavior (R=0.3). Using Logit analysis, past behavior could be explained with relevant variables in an acceptable power ($R^2$=0.35). In the model, education, social group, occupation, age and visiting frequency were all negatively related to past behabavior. Beliefs and normative belief also behaved as expected by the theory. The study results show that the theory may be useful in predicting the undesirable behaviors in recreation areas and establishing management policy to control them. The cause of weak relationships between relevant variables were discussed and future research implications were also suggested.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.36S no.9
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• pp.103-112
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• 1999

In this paper, a speaker-independent isolated world recognition system for a car navigation system is implemented using a general digital signal processor. This paper presents a method combining SNR normalization with RAS as a noise processing method. The semi-continuous hidden markov model is adopted and TMS320C31 is used in implementing the real-time system. Recognition word set is composed of 69 command words for a car navigation system. Experimental results showed that the recognition performance has a maximum of 93.62% in case of a combination of SNR normalization and spectral subtraction, and the performance improvement rate of the system is 3.69%, Presented noise processing method showed good speech recognition performance in 5dB SNR in car environment.

• Journal of the Korea Convergence Society
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• v.9 no.2
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• pp.183-190
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• 2018

We examined the level of Earnings Management of Socially Responsible Investment(SRI) Corporate by using Book-Tax Difference(BTD). We used 2,718 sample data from 2011 to 2016 on Korea Stock Exchange. In short, the result of this study's is as followed. Socially Responsible Investment(SRI) have a negative relevance with Book-Tax Difference(BTD). Therefore this study can support that a firm has a high level of Socially Responsible Investment(SRI) will have the better the Quality of Accounting according to our study. This study contributes as follow. we can confirm that the more Socially Responsible Investment(SRI) the better Quality of Accounting Information. And we hope that our study can be helped development of sound capital market and give a useful information to investors on firms that has a high level of Socially Responsible Investment(SRI).

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.32-32
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• 2008

X-ray detector는 의료용, 산업용 등 다양한 분야에서 사용되어지고 있으며 기존의 Analog X-ray 방식의 환경오염, 저장공간 부족, 실시간 분석의 어려움 등의 문제점들을 해결하기 위하여 Digital X-ray로의 전환과 연구가 활발하며 이에 따른 관심도 높아지고 있는 살점이다. Digital X-ray detector는 p-영역과 n-영역 사이에 아무런 불순물을 도핑하지 않은 진성반도체(intrinsic semiconductor) 층을 접합시킨 이종접합 PIN 구조의 photodiode 이다. 이 소자는 역바이어스를 가해주면 p영역과 n영역 사이에서 캐리어 (carrier)가 존재하지 않는 공핍 영역이 발생하게 된다. 이런 공핍 영역에서 광흡수가 일어나면, 전자-정공 쌍이 발생한다. 그리고, 발생한 전자-정공 쌍에 전압이 역방향으로 인가되는 경우, 전자는 양의 전극으로 이동하고, 정공은 음의 전극으로 이동한다. 이와 같이, 발생한 캐리어들을 검출하여 전기적인 신호로 변환 시킨다. 고해상도의 Digital X-ray detector를 만들기 위해서는 누설전류에 의한 noise 감소와 소자의 높은 안정성과 내구성을 위한 높은 breakdown voltage를 가져야 한다. 본 연구에서는 Digital X-ray detector의 leakage current 감소와 breakdown voltage를 높이기 위하여 guradring과 gettering technology를 사용하여 전기적 특성을 분석하였다. 기판으로는 $10k\Omega{\cdot}cm$ resistivity를 갖으며, n-type <111>인 1mm 두께의 4인치 Si wafer를 사용하였다. 그리고 pixel pitch는 $100{\mu}m$이며 active area는 $80{\mu}m{\times}80{\mu}m$인 $32\times32$ array를 형성하여 X-ray를 조사하여 소자의 특성을 평가 하였다.