• The Transactions of the Korean Institute of Electrical Engineers P
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• v.64 no.4
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• pp.333-336
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• 2015

Recently, the power load is growing larger and because of the environmental limitation of generation, the expansion of generation facilities are becoming more difficult. For that reason the importance of the demand-side resources come to be higher. One method of the demand-side resource, the DLC Program, has executed, and moreover, the loads which are available to be controlled are increasing. It should be considered of some kinds of power system components such as DLCs, because the fact that using the demand resources will be an important part of the power system. This paper considers the power factor of the load-bus which is shedded in the direct load control program. and then analyze the power system using flow sensitivity and voltage sensitivity. In this paper, we assumed two scenarios through the rank of the load power factor at each bus and to compare and evaluate each case, we used Power World for the simulation.

• Journal of Korean Institute of Industrial Engineers
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• v.17 no.1
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• pp.75-82
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• 1991

This research is concerned with Machine-Part Group Formation(MPGF) methodology for Flexible Manufacturing Systems(FMS). The purpose of the research is to develop a new heuristic algorithm for effectively solving MPGF problem. The new algorithm is proposed and evaluated by 100 machine-part incidence matrices generated. The performance measures are (1) grouping ability of mutually exclusive block-diagonal form. (2) number of unit group and exceptional elements, and (3) grouping time. The new heuristic algorithm has the following characteristics to effectively conduct MPGF : (a) The mathematical model is presented for rapid forming the proper number of unit groups and grouping mutually exclusive block-diagonal form, (b) The simple and effective mathematical analysis method of Rank Order Clustering(ROC) algorithm is applied to minimize intra-group journeys in each group and exceptional elements in the whole group. The results are compared with those from Expert System(ES) algorithm and ROC algorithm. The results show that the new algorithm always gives the group of mutually exclusive block-diagonal form and better results(85%) than ES algorithm and ROC algorithm.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2010.07a
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• pp.148-149
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• 2010

최근 널리 보급되고 있는 IPTV의 주요 서비스인 주문형 비디오 서비스의 시청 순위는 Zipf의 법칙을 따른다고 알려져 있으며 이를 기반으로 계층형 네트워크 스토리지 구조로 서비스를 제공하여 네트워크 비용과 스토리지 비용을 절감하고 있다. 그러나, 최근 연구에 의하면 미디어 시청 순위는 stretched exponential 함수에 더 근사함이 알려졌다. 본 연구에서는 국내에서 현재 상용 서비스 중인 대규모 주문형 비디오 서비스의 시청 순위-회수 데이터를 분석하여, 시청 순위로부터 stretched exponential 함수의 모수를 추정하여 시청 순위의 분포함수를 파악하고자 한다. 특히, 콘텐츠 파일 크기, 콘텐츠 파일 전달방식, 콘텐츠 장르 등의 요인과 시청 순위 분포함수의 모수 사이에 상관관계가 있는지 분석하고자 한다.

• Structural Engineering and Mechanics
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• v.62 no.3
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• pp.297-302
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• 2017

Structural reanalysis is frequently utilized to reduce the computational cost so that the process of design or optimization can be accelerated. The supports can be regarded as the design variables and may be modified in various types of structural optimization problems. The location, number, and type of supports can make a great impact on the performance of the structure. This paper presents a unified method for structural static reanalysis with imposition or relaxation of some support constraints. The information from the initial analysis has been fully utilized and the computational time can be significantly reduced. Numerical examples are used to validate the effectiveness of the proposed method.

• Journal of the Korean Society of Combustion
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• v.16 no.1
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• pp.1-7
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• 2011

340 MWe circulating fluidized bed (CFB) boiler in Yeosu power station is under construction. The circulating fluidized bed boiler in the Yeosu power plant has a number of differences from other domestic boilers in terms of scale and design. Evaluation of design parameters of the Yeosu CFB boiler should be required because the direct application of existing technology is limited. In this study, design characteristics of the Yeosu CFB boiler was summarized. And thermogravimetric analysis was conducted with comparing other rank coals. Watersteam side heat absorption, flue gas temperature and heat transfer coefficient were calculated by heat and mass balance. Design parameters for the Yeosu CFB boiler were discussed along with typical value in the CFB design range.

• The Korean Journal of Applied Statistics
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• v.25 no.3
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• pp.423-434
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• 2012

A two-sample test for equality of survival distribution is one of the important issues in survival analysis, especially for clinical and epidemiological research. With interval censored data, some testing methods have been developed. This study introduces some testing methods and compares them under various situations through simulation study. Based on simulation result, it provides some useful information on choosing the most appropriate testing method in a given situation.

• The Journal of Information Systems
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• v.10 no.1
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• pp.197-215
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• 2001

It is important to investigate into the critical success factors of the CIO system in order to formulate a successful introduction strategy of the system. In an effort to provide the background of the strategy, this research attempts to identify the characteristics of CIO's environment in Korea, such as the CEO, the colleagues, and the demographic statistics of the firm the CIO works for. A result from the analysis of data collected shows that about half the firms who responded to the survey have already adopted the CIO system. This implies that the value of the system is well recognized in Korea, considering that many of another half the firms are planning to adopt the system. Another result suggests that the bigger a firm is, the more the firm tends to adopt the CIO system and the higher the rank of CIO's colleagues is.

• Korean Journal of Child Studies
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• v.25 no.4
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• pp.163-175
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• 2004

In this study, 63 university seniors majoring Child Studies were in an 8-week Web Based Instruction (WBI) program. Student characteristics of learning motivation, self-regulatory learning strategy, and learning style (Kolb, 1985) were the independent variables. Learning effects as dependent variables were measured by paper test and work assessment. Spearman's $\rho$ was calculated and tests of rank order difference were used for the data analysis. Results showed that learning motivation and self-regulatory learning strategy had meaningful positive relations with learning effects on the paper test score. Learning effects showed differences by learning style. These findings indicated that the learner's characteristics should be considered in the design and development of more effective WBI environments.

• Korean Journal of Child Studies
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• v.30 no.4
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• pp.117-133
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• 2009

This study researched differences in friendship among children of the same and/or opposite sex and their gender-role identities. Friendship and gender-role identities among 423 children in the 5th and 6th grades were examined. Data was analyzed by MANOVA and ANOVA. Findings were : (1) there were some differences between boys and girls in rank order of the distribution of gender-role identity types : androgynous type was most common in girls; undifferentiated was most common among boys. (2) Results of friendship based on sex and gender-role identity showed that boys and girls with androgynous gender-roles were friendly with both boys and girls. Among boys, masculine types were particularly friendly with boys; among girls, masculine types were particularly friendly with girls.

• Journal of the Korea Society of Computer and Information
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• v.23 no.7
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• pp.73-80
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• 2018

There are various organizations in modern society, in which people have direct and indirect relationships. Internal structure of these organizations can be analyzed by the relationships which are officially pressed on the media. However, this task will be difficult when the media information is strictly limited, though the necessity of analyzing organization structure remains. In this study, we try to estimate the influence of North Korea's core members by using PageRank centrality to supplement the limitation of previous SNA analysis methods. Experimental results show that we can show and predict NK's power shifts more efficiently.