• Computers and Concrete
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• 제27권2호
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• pp.163-173
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• 2021

In this paper, the parameters of haunch height, reinforcement ratio and site condition were evaluated for the influence on the seismic performance of a composite precast fabricated utility tunnel by shaking table test and numerical simulation. The dynamic response laws of acceleration, interlayer displacement and steel strain under unidirectional horizontal seismic excitation were analyzed through four specimens with a similarity ratio of 1:6 in the test. And a numerical model was established and analyzed by the finite element software ABAQUS based on the structure of utility tunnel. The results indicated that composite precast fabricated utility tunnel with the good anti-seismic performance. In a certain range, increasing the height of haunch or the ratio of reinforcement could reduce the influence of seismic wave on the utility tunnel structure, which was beneficial to the structure earthquake resistance. The clay field containing the interlayer of liquefied sandy soil has a certain damping effect on the structure of the utility tunnel, and the displacement response could be reduced by 14.1%. Under the excitation of strong earthquake, the reinforcement strain at the side wall upper end and haunches of the utility tunnel was the biggest, which is the key part of the structure. The experimental results were in good agreement with the fitting results, and the results could provide a reference value for the anti-seismic design and application of composite precast fabricated utility tunnel.

• 한국생활과학회지
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• 제15권4호
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• pp.659-667
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• 2006

The purpose of this study is to identify the combinated factors of leaf mustard kimchi which confer the highest utility on tourists, and to establish the relative factors of importance in terms of tourists' contribution to total utility to their tour purpose. Conjoint model, $X^2$ analysis, Max. Utility model, BTL model, Logit model, K-means cluster analysis, and one-way ANOVA analysis are used for this study. The findings from this study are as follows: First, the Pearson's R and Kendall's tau($\tau$) statistics shows that the model fits the data well to the tourists' visit purpose. Second, when they choose a sightseeing place, tourists' taste for food renowned in the local area is a very important factor. Third, the leaf mustard kimchi some tourists most prefer has light red color and mild taste, and they buy it in a shaped packing, at a cheap price and directly at the kimchi factory. The leaf mustard kimchi the other tourists most prefer has light red color and highly pungent taste, and they buy it in a shaped packing, at a cheap price and directly at the kimchi factory. Fourth, by the results of BTL model and Logit Model analysis, some tourists most prefer an experimental model of leaf mustard kimchi which has light red color and mild taste. They want to buy it in a shaped packing, at a cheap price and directly at the kimchi factory. The other tourists most prefer an experimental model of leaf mustard kimchi which has light red color and highly pungent taste. They want to buy it in a shaped packing, at a cheap price and directly in the kimchi factory. Finally, the writer hopes this study will provide the kimchi marketers with some insights into the types of popular leaf mustard kimchi designs that could be successfully developed.

• 한국전자거래학회지
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• 제26권2호
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• pp.1-17
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• 2021

본 연구는 디지털헬스케어서비스에서 사용자기대와 사용자효용의 매개요인을 사용하여 서비스 품질의 특성들이 지속사용의도에 미치는 효과를 분석하였다. 첫째, 독립요인을 서비스품질 차원으로 통합하였으며, 기존 연구들을 토대로 독립요인들을 도출하였다. 도출된 독립요인은 기술적특성, 사용자특성, 의료서비스특성 등의 3개의 관점으로 구분하였으며, 각각의 독립요인 특성이 지속사용의도에 어떻게 영향을 주는지를 연구하였다. 둘째는 사용자기대와 사용자효용이라는 2개의 매개요인들이 독립요인과 종속요인을 매개하는지를 분석하였다. 본 연구에서는 357개의 설문을 사용하였으며 의미 있는 분석결과는 사용자특성 요인이 사용자기대와 사용자 효용 그리고 지속사용의도에 연속적으로 영향을 미치는 독립요인이라는 것을 발견하였다. 분석 결과을 요약하면 다음과 같다. (1) 사용자특성 요인은 사용자기대와 사용자효용 매개요인에 영향을 주고, 이들 매개요인들은 지속사용의도 종속요인에 영향을 미친다. (2) 기능성, 호환성 그리고 편의성 하위요인들로 구성된 기술적특성 독립요인과 혁신성 하위요인을 갖는 사용자 특성 독립요인은 사용자기대 매개요인에 영향을 주고, 사용자기대 매개요인은 지속사용의도 종속 요인에 영향을 준다. (3) 신뢰성, 운영용이성, 안전성 그리고 정확도 하위요인들로 구성된 의료 서비스특성 독립요인은 사용자효용 매개요인에 영향을 주고, 사용자효용 매개요인은 다시 지속 사용의도 종속요인에 영향을 미친다.

• 한국병원경영학회지
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• 제10권4호
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• pp.75-97
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• 2005

The research objective is to empirically investigate the compensation packages maximizing the utilities of internal customers by applying the market segmentation theory. Data was collected from four Korean hospitals in Seoul, Busan and Gyunggi-do. The research is designed to seek the compensation package maximizing the utility of doctors by mixture regression model, which has been applied as latent structure and other type of finite mixture models from various academic fields since early 1980s. The mixture regression model shows the optimal segments number and fuzzy classification for each observation by EM(expectation-maximization algorism). The finite mixture regression model is to unmix the sample, to identify the groups, and to estimate the parameters of the density function underlying the observed data within each group. The doctors were segmented into 5 groups by their preference for the compensation package. The results of this study imply that the utility of doctors increases with differentiated compensation package segmented by their preference.

• 한국전산유체공학회지
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• 제10권1호
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• pp.94-98
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• 2005

Accurate prediction of the fire-induced air velocity, temperature and smoke flow in underground utility tunnel becomes more important for the optimization of design and placement of heat and smoke detectors. In order to improve the safety of underground utility tunnel systems, the behaviors of fire-induced smoke flow and temperature distributions are investigated. Especially, two different cross-sectional shapes of tunnel, such as rectangular and circular types are modeled. Also, fire source is modeled as a volumetric heat source. Three-dimensional thermal-flow characteristics in an underground tunnel are solved by means of FVM using SIMPLE algorithm. The effects of shape geometry on the fire-induced flow characteristics are graphically depicted. It is desirable that heat and smoke detectors are installed on the cables and the top of the wall.

• 한국경영과학회:학술대회논문집
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• 한국경영과학회/대한산업공학회 2003년도 춘계공동학술대회
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• pp.972-975
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• 2003

The purpose of this study is to integrate Decision Theory Approach(DTA) and OR Theory Approach(OTA) systemically. and to develop Combination Theory Approach to build an optimal R&D project portfolio by strategies. To Integrate two approaches. Utility theory is introduced. Evaluation Results aye converted into utility values by the utility functions and the values are optimized by 0-1 programming. Scoring method and Integer programming is used to evaluation a correspondence with a goal and to allocation the limiting resources. And utility function is used to reflect the preference of decision makers on the project evaluation.

• Journal of the Korean Data and Information Science Society
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• 제23권2호
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• pp.365-374
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• 2012

Weather derivatives designed to manage casual changes of weather, as opposed to catastrophic risks of weather, are relatively a new class of financial instruments. There are still many theoretical and practical challenges to the effective use of these instruments. The objective of this paper is to develop a pricing approach for valuing weather derivatives and presents a case study that is practical enough to be used by the risk managers of electrical utility firms. Utilizing daily average temperature data of Guangzhou, China from $1^{st}$ January 1978 to $31^{st}$ December 2010, this paper adopted a univariate time series model to describe weather behavior dynamics and calculates equilibrium prices for weather futures and options for an electrical utility firm in the region. The results imply that the risk premium is an important part of derivatives prices and the market price of risk affects option values much more than forward prices. It also demonstrates that weather innovation as well as weather risk management significantly affect the utility's financial outcomes.

• 한국재난정보학회 논문집
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• 제19권3호
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• pp.665-672
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• 2023

연구목적: 지하공동구는 도시 지하에 전기, 수도, 가스 등의 인프라를 공동 수용하는 시설로 공기 흐름이 부족하여 계절에 상관없이 결로가 자주 발생한다. 결로는 전기 설비의 누전 화재를 일으키는 원인이 되므로 지하공동구 내의 조명 등 각종 시설물 관리를 위해 필요한 제어반은 결로에 노출되지 않도록 문이 닫힌 상태로 관리되어야 한다. 본 논문에서는 딥러닝 객체인식 기술을 활용하여 수km 거리에 반복 배치된 공동구 제어반의 문 열림 여부를 이동 카메라 조건과 조명이 꺼진 조건에서도 인식하고자 한다. 연구방법: 지하공동구를 순찰하는 로봇이 촬영한 영상데이터를 이용하여 딥러닝 객체인식 모델인 YOLO를 모자이크 이미지 증강기법으로 학습시켜 제어반 문 열림과 문 닫힘을 인식한다. 연구결과: 모자이크 이미지 증강기법으로 학습시킨 모델과 사용하지 않은 모델의 성능을 비교한 결과, 모자이크 학습 모델이 더 우수한 성능(모든 클래스에 대한 mAP가 0.994 이상임)을 보이는 것을 확인하였다. 결론: 지하공동구의 조명이 꺼진 상태에서도, 공동구 내부 시설물이 복잡한 환경에서도 제어반의 문열림 여부를 우수한 성능으로 인식하여 지하공동구 재난안전관리에 도움이 될 것으로 기대된다.

• Journal of Electrical Engineering and Technology
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• 제12권4호
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• pp.1484-1494
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• 2017

We present a two-stage inverter with high step-up conversion ratio engaging modified finite-set Model Predictive Control (MPC) for utility-integrated photovoltaic (PV) applications. The anticipated arrangement is fit for low power PV uses, the calculated efficiency at 150 W input power and 19 times boosting ratio was around 94%. The suggested high-gain dc-dc converter based on Cockcroft-Walton multiplier constitutes the first-stage of the offered structure, due to its high step-up ability. It can boost the input voltage up to 20 times. The 3S current-source inverter constitutes the second-stage. The 3S current-source inverter hires three semiconductor switches, in which one is functioning at high-frequency and the others are operating at fundamental-frequency. The high-switching pulses are varied in the procedure of unidirectional sine-wave to engender a current coordinated with the utility-voltage. The unidirectional current is shaped into alternating current by the synchronized push-pull configuration. The MPC process are intended to control the scheme and achieve the subsequent tasks, take out the Maximum Power (MP) from the PV, step-up the PV voltage, and introduces low current with low Total Harmonic Distortion (THD) and with unity power factor with the grid voltage.

• Nuclear Engineering and Technology
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• 제50권5호
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• pp.794-800
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• 2018

The proliferation resistance (PR) of Th/U and Th/Pu fuels used in CANada Deuterium Uranium for the deep geological repository was assessed by combining the multiattribute utility analysis proposed by Chirayath et al., 2015 with the transport model of radionuclides in the repository and comparing with that of the used natural U fuel case. It was found that there was no significant advantage for Th/U and Th/Pu fuels from the viewpoint of the PR in the repository. It was also found that the PR values for used nuclear fuels in the repository of Th/U, Th/Pu, and natural U was comparable with those for enrichment and reprocessing facilities in the pressurized water reactor (PWR) nuclear fuel cycle. On the other hand, the PR values considering the transport of radionuclides in the repository were found to be slightly smaller than those without their transport after the used nuclear fuels started dissolving after 1,000 years.