• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 춘계학술대회 논문집 전력기술부문
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• pp.84-88
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• 2001

This paper proposes a method of solving a unit commitment problem using parallel tabu search (PTS). The TS is efficient optimization method using meta-heuristic. In this paper, to reduce the computation time for evaluating the neighborhoods, an evaluating method only on changed part and a path relinking method as diversification strategy are proposed. To show the usefulness of the proposed method, we simulated for 10 units system and 110 units system. Numerical results show improvements in the generation costs and the computation time compared with conventional methods. Numerical results show improvements in the generation cost and the computation time compared to previously obtained results.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 C
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• pp.1098-1100
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• 1999

This paper proposes a method of solving a unit commitment problem using tabu search (TS). The TS is efficient optimization method using meta-heuristic. To improve the diversification properties of TS, path relinking method is introduced. To show the usefulness of the proposed method, we performed an experiment for the system of 10 units. Numerical results show improvements in the generation cost and the computation time compared to previously obtained results.

• 대한전기학회논문지
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• 제37권10호
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• pp.675-682
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• 1988

An improved algorithm for optimal daily hydrothermal unit commitment is proposed in this paper. Especially, for the purpose of guarantee on the existence of feasible solution all the time, the secondary states as well as the primary state are considered at each step in the procedure of solution by Hybird Dynamic Programming to solve the problem of which solution may not exist due to the increased number of constraints to be taken into account. The computational problem which may be caused in the course of considering secondary policies through whole steps of the period examined is solved by the heuristic judgement in every step taking load variation rates into account. The effectivness of the algorithm has been demonstrated by applying it to a sample power system.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 C
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• pp.1003-1005
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• 1998

We present the implementation of a Lagrangian Relaxation based large scale thermal Unit Commitment problem. The problem is decomposed into thermal subproblem by using Lagrangian multipliers. The thermal subproblem is solved by using dynamic programmmg. we perform a numerical test using the thermal system of KEPCO over a week (168 hours) period. The programming language used for the test program is C. The result is compared with the priority list method.

• 대한전기학회논문지:전력기술부문A
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• 제52권9호
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• pp.550-556
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• 2003

Price-based unit commitment is one of bidding strategies which a Genco may take in a practical manner. For that purpose, it is required for a Genco to decide output levels of its generators at each trade period. In this paper, an economic dispatch of thermal units is proposed considering the quantity of reserve contracts. A gradient projection algorithm is adopted as an optimization tool. A direct form of a projection matrix without any calculation of matrix inverse and multiplications is induced. Besides, it is proved that there is no need to check one of the two optimality conditions in the gradient projection method, which also requires matrix inverse and multiplications.

• 대한전기학회논문지
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• 제34권6호
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• pp.220-229
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• 1985

This paper proposes a new optimal unit commitment algorithm for the rational operation of electric power systems. Especially, the algorithm is improved by considering transmission line capacity limits and load forecasting uncertainty with the consideration of the participation factors of each units, so that the method becomes more reliable and flexible one. The transmission losses are considered by using updated penalty factors obtained from the constant matrixes of the fast decoupled load flow method, the system loads are distributed at each buses, and the several necessary operational constraints are also considered for the purpose of presenting a more practicable scheme. Finally, the effectiveness of the proposed algorithm has been demonstrated by applying to the 23-bus model system.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1987년도 전기.전자공학 학술대회 논문집(I)
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• pp.648-651
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• 1987

• 임상간호연구
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• 제23권1호
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• pp.110-119
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• 2017

Purpose: The purpose of this study was to test validity and reliability of the Korean-Sieloff King Assessment of Group Outcome Attainment within organization in Korea (K-SKAGOAO), and also to explore the relationship of Korean nursing group power and job satisfaction, organizational commitment, organizational performance. Methods: Participants were 481 nurse managers, nurse unit managers or staff nurses with over 7 years experience. Data were collected by post mail and analyzed using descriptive statistics, ANOVA, Kruskal-Wallis test, Tukey test, and Spearman's correlation. Results: Content Validity Index was over .82 and Cronbach's ${\alpha}$ coefficient for the K-SKAGOAO was .97. The mean score for Korean nursing group power was 136.77 among the total participants, 139.89 among nurse managers, 136.74 among nurse unit managers and 132.47 among staff nurses. These results showed high nursing group power in Korea nursing organization in hospitals. There was also a significant difference according to nurse position (p=.003). Korean nursing group power was positively related to job satisfaction, organizational commitment, and organizational performance. Conclusion: Findings show that the K-SKAGOAO has validity and reliability. Nursing groups can use the K-SKAGOAO to evaluate the nursing group power of each nursing organization and to develop strategies to improve nursing power and nursing outcomes.

• 한국수자원학회논문집
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• 제32권5호
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• pp.525-535
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• 1999

유역내의 수력 에너지자원과 수자원의 효율적 관리를 위하여 통합혼합정수계획법(combined mixed integer proguamming)을 사용한 최적 발전기 운영계획 모형을 개발하였다. 통합혼합정수계획법 모형은 기왕에 개발된 혼합정수계획법 모형에서 발생할 수 있는 모순을 해결하기 위하여 개발되었다. 또한, 조건부 제약조건과 택일 제약조건들을 선형계획법 모형에서 사용 할 수 있도록 수정하는 기법을 제안하였다. 미국 콜로라도강 하부유역에 통합혼합정수계획법을 적용한 경우를, 최적화 모형을 사용하지 않은 경우 및 혼합정수계획법을 사용한 경우와 비교한 결과, 최적화 기법을 사용하지 않은 경우보다 유역효율이 0.67% 증가하였고, 혼합정수계획법을 사용한 경우보다 유역효율이 1.53% 감소하였다. 통합혼합정수게획모형의 효율이 감소한 이유는 혼합정수계획법모형보다 전력요구량과의 허용오차를 감소시켰기 때문인 것으로 판단된다.

• 대한간호학회지
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• 제50권6호
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• pp.757-777
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• 2020

Purpose: The purpose of this study was to identify the outcome variables of nursing unit managers' transformational leadership and to test a hypothetical model using meta-analytic path analysis. Methods: A systematic review and meta-analysis were conducted in accordance with PRISMA guidelines. Data analysis, conducted using R version 3.6.2 software, included 49 studies for the meta-analysis and 119 studies for meta-analytic path analysis. Results: In the meta-analysis, four out of 32 outcome variables were selected. These four variables were empowerment, nursing performance, job satisfaction, and organizational commitment, which showed larger effect sizes than the median and more than five k. The hypothetical model for the meta-analytic path analysis was established by using these four variables and transformational leadership. A total of 22 hypothetical paths including nine direct effects and 13 indirect effects were set and tested. The meta-analytic path analysis showed that transformational leadership had direct effects on the four variables. Finally, eight direct effects, 12 indirect effects, and six mediating effects were statistically significant, and the hypothetical model was verified. Conclusion: Nursing unit managers can use the transformational leadership to improve empowerment, nursing performance, job satisfaction, and organizational commitment of nurses. This study empirically showed the importance of transformational leadership of nursing managers. This finding will be used as evidence to develop strategies for enhancing transformational leadership, empowerment, nursing performance, job satisfaction, and organizational commitment in nursing science and practice.