• 대한전자공학회논문지TC
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• 제39권6호
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• pp.19-19
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• 2002

본 고에서는 최선형 인터넷 서비스에 대해서 대역공유량의 변화가 가지는 특성을 이론적으로 모델링하는 방법을 제안한다. 그리고 유틸리티에 기반한 요금정책을 제안하고 수치실험을 통해 제안방법의 의의와 효과에 대해 검토한다.

• 대한전자공학회논문지TC
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• 제39권6호
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• pp.277-284
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• 2002

본 고에서는 최선형 인터넷 서비스에 대해서 대역공유량의 변화가 가지는 특성을 이론적으로 모델링하는 방법을 제안한다. 그리고 유틸리티에 기반한 요금정책을 제안하고 수치실험을 통해 제안방법의 의의와 효과에 대해 검토한다.

• 한국안전학회지
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• 제31권3호
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• pp.143-155
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• 2016

Recently, a massive loss of life and property is occurring in Korea due to traffic accidents, with the rapid increase in cars. For improvement of traffic safety, the Korea Transportation Safety Authority intensively analyzes accident data in local governments with low traffic safety index, performs a field investigation to extract problems and offers local governments improvements for problems, by conducting the 'Special Survey of Actual Conditions of Traffic Safety' each year, starting 2008. But local governments cannot strongly push forward the improvement projects due to the limited budget and the uncertainty of the improvement plan effects. Therefore, this study suggested a model which applied the Utility concept to the AHP theory, in order to efficiently decide a priority of the improvement plans in accident black spots in consideration of the limited budget of local governments. The number of accidents in each spot for improvement and accident severity, traffic volume, pedestrian volume, the improvement project cost and the accident reduction effect were chosen as evaluation factors for deciding a priority, and data about the improvement plan costs and the accident reduction effects, traffic accidents and traffic volume in the spots to undergo the special research on the real condition of traffic accident in the past were collected from the existing studies. Then, regression analysis was carried out and the Utility Curve of each evaluation factor was computed. Based on the AHP analysis findings, this study devised a priority decision method which calculated the weight and the utility function of each evaluation factor and compared the total utility values. The AHP analysis findings showed that among the evaluation factors, accident severity had the biggest importance and it was followed by the improvement plan cost, the number of accidents, the improvement effect, traffic volume and pedestrian volume. The calculated utility function shows a rise in utility, as the variables of the 5 evaluation factors; the number of accidents, accident severity, the improvement plan effect, traffic volume and pedestrian volume increase and a fall in utility, as the variables of the improvement plan cost increase, since the improvement plan cost is included in the budget spent by a local government.

• 대한교통학회지
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• 제27권2호
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• pp.157-168
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• 2009

개인여객이 운송수단을 선택하여 얻는 효용은 시간, 비용 등의 운송특성과 소득 등 개인특성의 함수이다. 기존 연구에서는 일반적으로 운송특성이 여객효용에 미치는 효과를 추정하기 위한 방법으로 운송특성변수에 대해 선형인 효용함수를 전제로 한 무작위 효용모형을 이용하여 왔다. 그러나 본 논문에서는 개인여객의 효용극대화를 분석하는 방법으로서 운송수단선택행위가 소비, 여가, 소득창출 등 보다 본원적인 활동으로부터 파생된다는 점에 주목하여, 다시 말해, 개인의 본원적 활동에 따른 효용극대화 관점에서 운송수단선택에 따른 효용이 진정으로 선형의 형태를 지니고 있는지를 살펴보았다. 이론적 결론은 첫째, 본원적 활동에 따른 효용이 소비와 여가만의 함수일 때 선형가정은 운송시간의 일부구간에서 진실이다. 둘째, 만일 효용이 노동활동이나 운송시간에 의해 직접 영향을 받을 경우 운송특성에 따른 효용의 선형성은 극단적인 상황이 아니면 성립하지 않는다. 따라서 운송특성에 따른 효용의 크기를 추정하기 위해선 선형이 아닌 보다 일반화된 함수에서의 근사가 요구된다.

• 전력전자학회논문지
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• 제8권2호
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• pp.199-210
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• 2003

본 논문에서는 계통연계형 태양광발전시스템의 고립운전방지를 위한 새로운 고리운전 검출기법을 연구한다. 이를 위하여 계통연계형 태양광발전시스템 및 고립운전시의 특성에 대하여 기술하였다. 또한 고립운전의 검출특성을 향상시키기 위한 새로운 검출기법을 제시하고 해석하였으며 검출시험을 위한 부하조건 선정을 위한 부하임피던스 곡선을 해석적으로 유포하였다 ACSL 시뮬레이션 및 실험을 통하여 제시한 고립운전 검출기법 및 해석결과를 검증하였다.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2006년도 춘계학술대회 논문집
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• pp.365-369
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• 2006

It is concentrated on a methodology to establish a scheme of investment on power distribution systems of components. This paper provides a methodology to estimate the scheme as using a customer interruption cost regarding reliability indices in power distribution systems. The proposed method basically uses the failure rate depending on time for explaining the deterioration of a component. Therefore, the theory of the sensitivity is used for deciding the precedence of the investment to consider an effect of each component's failure rate on the system reliability. After Estimating the sensitivity on component investment cost making incremental reliability level is produced by component's investment cost accumulated according to the precedence of the sensitivity. After that, the failure rate corresponding with reliability level on the curve of investment cost is used as producing the curve of customer interruption cost. Two curves have the crossing point that is proposed to acceptable reliability level for customer and utility. In this paper, the acceptable reliability level for customer with the utility is assessed to analyze customer interruption cost and sensitivity of reliability indices. In conclusion the result of investment based on this method is shown to the reliability level with two cost.

• 한국전산구조공학회논문집
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• 제29권5호
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• pp.413-419
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• 2016

지진시 사회 인프라시설물의 피해는 시설물 자체의 피해보다 사회 전반에 걸친 2차 피해를 야기한다. 그 중, 지하 공동구 구조물은 통신, 가스, 전기 등 사회의 라이프라인에 해당하여 지진에 대한 취약성을 정확히 평가하여야 할 필요가 있다. 따라서, 본 연구에서는 지하 공동구의 지진 발생 지반가속도에 따른 파괴가능성을 평가하였다. 평가를 위한 입력지반운동은 해외 실측 지진데이터와 한반도에서 발생가능한 인공지진파를 차용하였으며, 지진해석 방법은 응답변위법과 시간이력해석법을 사용하였다. 파괴여부를 판별하는 한계상태는 휨모멘트와 전단 파괴를 바탕으로 하였다. 취약도 함수 도출을 위한 방법은 최우도법이 사용되었으며, 그 분포함수는 대수정규분포로 가정하였다. 이는 지진시 지하 공동구 시설물의 피해 평가는 물론 지하 공동구 시설물의 내진설계를 위한 기초자료로 활용될 수 있다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1991년도 하계학술대회 논문집
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• pp.411-416
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• 1991

Operation simulation is a key factor to evaluate investment and operation in a power utility. Probabilistic production simulation is of major concern. With pumped-storage plant, production simulation is not an easy task, because its economy should fully be exploited. In addition, usual operation interval is a week rather than a day. Most existing models are based on approximate production simulation such as adopting simple priority orders of generations. This study is based on the more elaborate model developed by authors. Further, a policy of weekly coordination is established based on the Maximum Principle. Chronological load curve instead of usual load duration curve is used and the accuracy in simulation is enhahced. Resulting economics are compared. Deviation between these two toad curve is shown.

• 천문학회보
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• 제37권2호
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• pp.89.1-89.1
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• 2012

Type Ia Supernovae are known as one of the most reliable standard candle regarding to our understanding their explosion mechanism. Recently NIR photometry of SN Ia shows us better promise on the distance measurement. NIR peak luminosity is relatively independent of light curve shape and effect of extinction is obviously less than in optical wavelengths. Among NIR bands, Y-band photometry is suggested to have less scatter and reduced reddening effect than other NIR wavelengths, furthermore it is still unexplored regime to verify its utility. Here we report Y-band light curve analysis of M101 SN Ia to investigate how Y-band can help us to determine accurate distance to the galaxy.

• 호남수학학술지
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• 제36권3호
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• pp.695-706
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• 2014

Various properties of digital covering spaces have been substantially used in studying digital homotopic properties of digital images. In particular, these are so related to the study of a digital fundamental group, a classification of digital images, an automorphism group of a digital covering space and so forth. The goal of the present paper, as a survey article, to speak out utility of digital covering theory. Besides, the present paper recalls that the papers [1, 4, 30] took their own approaches into the study of a digital fundamental group. For instance, they consider the digital fundamental group of the special digital image (X, 4), where X := $SC^{2,8}_4$ which is a simple closed 4-curve with eight elements in $Z^2$, as a group which is isomorphic to an infinite cyclic group such as (Z, +). In spite of this approach, they could not propose any digital topological tools to get the result. Namely, the papers [4, 30] consider a simple closed 4 or 8-curve to be a kind of simple closed curve from the viewpoint of a Hausdorff topological structure, i.e. a continuous analogue induced by an algebraic topological approach. However, in digital topology we need to develop a digital topological tool to calculate a digital fundamental group of a given digital space. Finally, the paper [9] firstly developed the notion of a digital covering space and further, the advanced and simplified version was proposed in [21]. Thus the present paper refers the history and the process of calculating a digital fundamental group by using various tools and some utilities of digital covering spaces. Furthermore, we deal with some parts of the preprint [11] which were not published in a journal (see Theorems 4.3 and 4.4). Finally, the paper suggests an efficient process of the calculation of digital fundamental groups of digital images.