• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2011.11a
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• pp.498-501
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• 2011

본 연구에서는 방염제가 적용되는 방염대상물에 대한 검정기술기준과 목조문화재에 적용되는 방염제의 검정기준의 차이에 대해 비교하여 보았으며 이를 통해 단청 등이 도색되어 있는 대부분의 목조문화재에 적용되는 방염제의 성능과 방염 처리되어진 일반 목재의 방염성능평가방법에 대하여 생각해 보았다. 목조문화재용 방염제 검정기준 내의 방염성 평가는 소방방재청 고시 제 2009-31호의 "방염제의 형식승인 및 검정기술기준"과 비교하였을 때 목재를 비교대상으로 할 경우 방염성능 기준 및 측정방법과 동일하거나 거의 유사하였으며 방염제의 물성 등에 대한 기본적인 평가방법 또한 동일한 것으로 나타났다. 그러나 시험시편에 대한 규정에 있어서 목조문화재용 시험편의 경우 일정 두께이하로 규정하고 있어 시험하는 시편의 두께에 따라 방염성능 평가기준에 도달하지 못하는 경우가 발생할 수 있을 것으로 판단되어진다.

• The Korean Journal of Applied Statistics
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• v.32 no.5
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• pp.753-761
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• 2019

A test procedure based on a Kendall's τ statistic is proposed for the association of bivariate interval censored data. In particular, a leverage bootstrap technique is applied to replace unknown failure times and a classical adjustment method is applied for treating tied observations. The suggested method shows desirable results in simulation studies. An AIDS dataset is analyzed with the suggested method.

• Environmental and Resource Economics Review
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• v.13 no.2
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• pp.175-194
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• 2004

Volumes of research have been implemented to estimate and predict the oil price. These models, however, fail in accurately predicting oil price as a model composed of only a few observable variables is limiting. Unobservable variables and news that have been overlooked in past research, yet have a high likelihood of affecting the oil price. Hence, this paper analyses the news impact on the price. The standard GARCH model fails in capturing some important features of the data. The estimated news impact curve for the GARCH model, which imposes symmetry on the conditional variances, suggests that the conditional variance is underestimated for negative shocks and overestimated for positive shocks. Hence, this paper introduces the asymmetric or leverage volatility models, in which good news and bad news have different impact on volatility. They include the EGARCH, AGARCH, and GJR models. The empirical results showed that negative shocks introduced more volatility than positive shocks. Overall, the AGARCH and GJR were the best at capturing this asymmetric effect. Furthermore, the GJR model successfully revealed the shape of the news impact curve and was a useful approach to modeling conditional heteroscedasticity.

• Survey Research
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• v.3 no.2
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• pp.47-76
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• 2002

Starting point bias arises in the iterative bidding framework when the initial bid influences respondent's final bids. The bidding game has become the most commonly used method of asking the valuation question in contingent valuation studies. A bidding game is typically conducted by either personal or telephone interview. Bidding begins with an interviewer positing an initial bid (starting bid) to a respondent. If the respondent is willing to pay the initial bid, the interviewer revises the bid upward until a negative respondent is obtained. A negative response to the initial bid downward until an acceptable amount is found. The final bid is a measure of the respondent's Hicksian compensating or equivalent surplus for the item being valued. This paper explicity tested for starting point bias in bidding games. That is, it was asked whether final bids are influenced by the magnitude of the starting bids in the process of valuating the WTP when to improve the quality of running water in Seoul and its vicinity. The result shows staring point bias exists in the present data and its magnitude is ${\delta}$=-0.265237.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.23 no.1
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• pp.51-54
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• 1978

3∼6m long plot with 3-4 replications will be practical for yield trials in the early hybrid generations. The C. V. values with 9m long plot was about 6.6％ in variety Yudal and 13.9％ in 12m plot. These results indicate that 9-12m plot with 3-4 replications could be employed in securate yield test in the advanced generations.

• Survey Research
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• v.4 no.2
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• pp.63-86
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• 2003

The objective of this study was to investigate the existence of starting point bias in the bidding game contingent valuation elicitation technique when determining willingness to pay (WTP) for improving the qualify of running water in Seoul and its vicinity. Of all existing contingent techniques, the bidding game most closely mimics the normal price taking behavior in local markets. Three different starting points (low, medium and high) were used to determine WTP and the existence of starting point bias in the meanwhile respectively. The respondents were randomly assigned to the three different starting point groups in order to ensure homogeneity, so that any variation seen in WTP could be attributed to the starting point effects. And a pretested interviewer-administered questionnaire used to elicit WTP. Non-parametric test and the logit model were used to analyze the data for evidence of starting point bias. In this instance, the high starting point group had a high WTP, and low starting point group had a low WTP. This means there exist starting point bias in estimating WTP by bidding game in this instance. This finding might signal that people may actually be making up their minds on the maximum amount they are willing to pay for running water service as a bidding iterating is going on and is influenced by the starting point used in the bidding game. The problem of slaking point bias can be avoided if the respondent is asked directly for the maximum WTP without payment cards or a bidding game. But such a question is perceived as being very difficult to answer and this leads to problems of non-response and being unrealistic.

• Proceedings of the Korea Water Resources Association Conference
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• 2017.05a
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• pp.399-400
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• 2017

홍수나 가뭄 등 극치 현상의 통계분석 및 빈도해석에 있어 극치분포형이 널리 사용되고 있으며, 이러한 극치분포형의 특성을 이해하기 위해서는 분포형의 오른쪽 꼬리(right tail) 부분 특성을 자세히 분석할 필요가 있다. 이에 따라 본 연구에서는 Monte Carlo 모의를 통하여 다양한 극치분포형의 오른쪽 꼬리 부분의 통계적 특성 및 그 예측 능력을 연구하였다. 극치분포형으로는 우리나라 확률수문량 산정에 널리 활용되고 있는 generalized extreme value (GEV), Gumbel, generalized logistic 분포를 사용하였으며, 매개변수 산정 방법으로는 확률가중모멘트법을 사용하였다. 모의실험의 모분포로는 수문빈도해석에서 많이 사용되는 GEV 분포를 사용하였고, 30년 이상 자료를 보유한 기상청 지점 자료의 왜곡도를 조사하여 모의실험에 사용되는 모집단의 왜곡도로 가정하여 표본 자료를 발생시켰다. 예측 능력의 평가는 재현기간 10~1000년의 확률수문량을 왜곡도계수를 고려한 GEV 도시위치공식을 이용하여 GEV 확률지에 도시하고, 평균제곱근오차(root mean square error), 편의(bias), 평균상대오차(mean relative difference), 평균절대상대오차(mean absolute relative difference)를 이용하여 최적 분포형을 선정함으로써 이루어진다. 또한 예측 능력 평가결과의 타당성 확인을 위해 극치분포형의 적합정도를 잘 나타낸다고 알려진 modified Anderson-Darling 방법의 검정결과와 비교하여 적절성을 확인하였다.

• Journal of the Korea Convergence Society
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• v.8 no.12
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• pp.291-298
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• 2017

In recent years, the increase of secondary controls within vehicles requires a mechanism to integrate various controls into a single device. This paper presents control performance of an integrated magnetorheological (MR) haptic device which can adjust various in-vehicle comfort instruments. As a first step, the MR fluid-based haptic device capable of both rotary and push motions within a single device is devised as an integrated multi-functional instrument control device. Under consideration of the torque and force model of the proposed device, a magnetic circuit is designed. The proposed MR haptic device is then manufactured and its field-dependent torque and force are experimentally evaluated. Furthermore, an inverse model compensator is synthesized under basis of the Bingham model of the MR fluid and torque/force model of the device. Subsequently, haptic force-feedback maps considering in-vehicle comfort functions are constructed and interacts with the compensator to achieve a desired force-feedback. Control performances such as reflection force are experimentally evaluated for two specific comfort functions.

• Elastomers and Composites
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• v.45 no.2
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• pp.94-99
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• 2010

340 nm UV radiation of $2500\;kJ/m^2$ irradiated a thermoplastic elastomer (TPE) specimen used for interior and exterior materials of a car. After the UV irradiation, the black sample surface was changed to gray. Materials on the aged sample were collected and analyzed using GC/MS, but significant materials were not found. Lots of small cracks were found on the aged specimen surface. Whitening phenomenon of the aged sample disappeared by brushing or searing with a fire on the aged surface. After brushing or searing with a fire, small cracks on the surface vanished. Samples before and after the aging, and the treated samples with brush or fire were analyzed using image analyzer, SEM, EDX, and ATR and the results were compared. The vanished whitening phenomenon by brushing or searing was explained with filling the small cracks by polypropylene of TPE.

• Journal of Venture Innovation
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• v.6 no.1
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• pp.1-16
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• 2023

Due to the progress of the 4th industrial revolution and the COVID-19 pandemic, the subscription economy was rapidly expanding. In particular, the subscription economy was expected to expand further as the servicing of products(servitization) rapidly progresses. In this study, we tried to empirically analyze the factors that promote and hinder the spread of the subscription economy from the consumer's point of view. To this end, based on the Service Profit Chain (SPC) model, which identified mechanisms leading from quality to satisfaction, loyalty, and performance, a research model was established by combining the framework of the Value-based Adoption Model (VAM), which covers both benefit and sacrifice factors. Usefulness and convenience were derived as benefit factors, and perceived risks and perceived costs were derived as sacrifice factors. The effects of these factors on satisfaction and continuous use intention were analyzed. For empirical analysis, a survey was conducted targeting people who have experience in subscription economy, and 300 effective samples were analyzed. The analysis was performed as a structural equation model using AMOS 24. As a result of the empirical study, it was found that convenience had a significant positive (+) effect on satisfaction. Perceived risk and perceived cost were analyzed to have a negative (-) effect on satisfaction. On the other hand, usefulness was found to have no significant effect on satisfaction. The influences affecting satisfaction were in the order of perceived cost, convenience, and perceived risk. Satisfaction was found to have a significant positive (+) effect on continuous use intention. The results of this study were considered meaningful in that they broadened the horizons of research by combining existing validated models at the academic level and testing their validity, and found that perceived cost was still an important factor at the practical level.