• 국제학술발표논문집
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• The 1th International Conference on Construction Engineering and Project Management
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• pp.935-940
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• 2005

This paper presents the results of a statistical analysis using historical data of cost contingency. As a result, a model that predicts and estimates an accurate cost contingency value using the least squares estimation method was developed. Data such as original contract amounts, estimated contingency amounts set by maximum funding limits, and actual contingency amounts, were collected and used for model development. The more effective prediction model was selected from the two developed models based on its prediction capability. The model would help guide project managers making financial decisions when the determination of the cost contingency amounts for multiple projects is necessary.

• 전기학회논문지
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• 제59권2호
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• pp.232-241
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• 2010

This paper describes the development of robust contingency analysis program for Korean Energy Management System. The important function of contingency analysis is to determine the bus/branch model for contingency, and to calculate the state of the power network based on the network model and topology output. In the proposed method, the bus/branch models for contingencies are determined exactly using a fast linked-list method based on the application common model database. To calculate the state of the power system included contingency, the full-decoupled powerflow approach, the partial powerflow method for contingencies and the proposed contingency screening algorithm are also used to contingency analysis. To verify the performance of the developed processor, we performed a file-based test using several structured input data and online test using the database which resides on memory. The results of these comprehensive tests showed that the developed processors can accurately calculate the power system contingency state from online data and can be applied to Korea Power Exchange system.

• Communications for Statistical Applications and Methods
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• 제10권3호
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• pp.997-1005
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• 2003

We can use the logistic model for categorical data when the response variables are binary data. In this paper we consider the problem of constructing the confidence intervals for logistic model in I${\times}$J${\times}$2 contingency table. These constructions are simplified by applying logit transformation. This transforms the problem to consider linear form which called the logit model. After obtaining the confidence intervals for the logit model, the reverse transform is applied to obtain the confidence intervals for the logistic model.

• 한국국방경영분석학회지
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• 제25권2호
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• pp.158-169
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• 1999

This paper is concerned with the application of generalized linear interactive modelling(GLIM) to the binary categorical data. To analyze the categorical data given by a contingency table, finding a good-fitting loglinear model is commonly adopted. In the case of a contingency table with a response variable, we can fit a logit model to find a good-fitting loglinear model. For a given $2^4$ contingency table with a binary response variable, we show the process of fitting a loglinear model by fitting a logit model using GLIM and SAS and then we estimate parameters to interpret the nature of associations implied by the model.

• 대한전기학회논문지
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• 제39권2호
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• pp.133-141
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• 1990

In the operation of an electric power system, the voltage security of the system has acquired more significant importance after the occurrence of large system black-outs caused by voltage collapse several times. This paper describes a fast contingency screening method concerning voltage security. The method defines a voltage-sensitive buses where significant voltage changes would occur as a result of the contingency to reduce the number of bus voltages to be solved for continngency screening. This method is based on the observation that it is not necessary to solve the entire network in most contingency cases because boltage changes actually occur around the contingency. The P-Q decoupled linearized model and the fast error correction method are also adopted in the method to define voltage-sensitive buses and to calculate voltage magnitude on the selected voltage-sensitive buses fastly and reliably. The method suggested in this papaer has been tested in IEEE 30-bus model system and KEPCO 130-bus actual system and its effectiveness for practical use has also been confirmed.

• Architectural research
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• 제16권2호
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• pp.75-80
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• 2014

Risks, uncertainties, and associated cost overruns are critical problems for construction projects. Cost contingency is an important funding source for these unforeseen events and is included in the base estimate to help perform financially successful projects. In order to predict more accurate contingency, many empirical models using regression analysis and artificial neural network method have been proposed and showed its viability to minimize prediction errors. However, categorical factors on contingency cannot have been treated and thus considered in these empirical models since those models are able to treat only numerical factors. This paper identified potential factors on contingency in transportation construction projects and evaluated categorical factors using the one-way ANOVA statistical method. Among factors including project work type, delivery method type, contract agreement type, bid award type, letting type, and geographical location, two factors of project work type and contract agreement type were found to be statistically important on allocating cost contingency.

• 전기학회논문지P
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• 제54권2호
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• pp.67-72
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• 2005

This paper presents a method to select contingency ranking considering voltage security problems in power systems. Direct method which needs not the detailed knowledge of the post contingency voltage at each bus is used. Based on system operator's experience and knowledge, the membership functions for the MVAR mismatch and allowable voltage violation are justified describing linguistic representation with heuristic rules. Rule base is used for the computation of severity index for each contingency by fuzzy inference. Contingency ranking harmful to the system is formed by the index for security evaluation. Compared with 1P-1Q iteration, this algorithm using direct method and fuzzy inference shows higher computation speed and almost the same accuracy. The proposed method is applied to model system and KEPCO pratical system which consists of 311 buses and 609 lines to show its effectiveness.

• 응용통계연구
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• 제17권2호
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• pp.337-346
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• 2004

랜덤표본에 관한 이원분할표의 독립성검정에는 통상 피어슨의 카이제곱적합도검정과 우도비검정을 사용한다. 그러나 랜덤표본이 아닌 집락자료에 관한 분할표의 경우에는 이들 검정법은 잘못된 결과를 나타낸다. 이러한 경우에는 공변량의 고정효과 외에 집락에 따른 변량효과를 함께 포함하는 일반화선형혼합모형을 고려함으로써 집락간의 이질성과 집락내의 종속성을 반영할 수 있다. 본 연구에서는 집락자료의 분할표에 대한 일반화선형혼합모형을 소개하고 실례를 통하여 이들 모형의 적합에 대해 논의한다.

• 한국경영과학회:학술대회논문집
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• 한국경영과학회/대한산업공학회 2005년도 춘계공동학술대회 발표논문
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• pp.1072-1082
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• 2005

This study develops a contingency fit between client IT capability and vendor competence in IS outsourcing relationship by integrating both the contingency theory in organization and the relationship theory in IS outsourcing. By adopting a fit as a moderation, the relationship intensity of IS outsourcing is hypothesized to be influenced by the fit between client IT capability and vendor competence, thereby leading to the success of outsourcing. The testing data was obtained from 20 IS outsourcing projects from both clients and vendors in Korea. The research model proposed in this study was then tested using the structural equation model (SEM). As expected, the result shows that when there is a fit between client IT capability and vendor competence, higher level of relationship intensity and outsourcing success exhibits. The findings have significant impactions for further research and practice.

• Journal of Information Technology Applications and Management
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• 제13권2호
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• pp.145-162
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• 2006

Despite the careful attention paid by managers and researchers to the effective administration of the S/W Development Project, there are cases where the project goes over-budget or misses deadlines. Existing research blames these problems on task complexity or mismanagement. In order to verify the results that varied according to the fitness between the Task Characteristics and the Project Management Types, a contingency model was employed. The verification of the contingency model demonstrated that the greater the task complexity, the greater the effectiveness of the project coordination, and the lesser the task complexity, the greater the effectiveness of project control. This research is theoretically important in that it develops a composite model to verify the relation between the three factors of Task Characteristics, Project Management Types, and Project Performance that compose the S/W Development Project.