• 대한전기학회논문지
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• 제37권6호
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• pp.331-338
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• 1988

A simple algorithm is presented for solving the thermal unit commitment problem which is one of very important areas in economic operation of power systems. This algorithm is based on simple priority ordering by the unit operation cost and it is shown that the operation cost of chosen sets of generators is the minimum. The proposed method differs from the conventional priority-based formulations in that the unit operation are calculated in every load level. Further the poerating reserve requiements are satisfied by the newly derived analytical security function or the expectation of reserve. The proposed method is proven to be very simple, accurate and efficient in a sample system.

• 간호행정학회지
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• 제22권4호
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• pp.353-361
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• 2016

Purpose: The purpose of this study was to investigate the association between self-leadership, team trust, organizational commitment and identify the influencing factors on organizational commitment. Methods: The subjects in the study were 296 conveniently selected general nurses at 2 general hospitals in Chungbuk Province. The measurements included the self-leadership, organizational trust inventory (OTI), and organizational commitment. Results: The mean score for self-leadership was 3.40, the mean score for OTI was 3.61, and the mean score for organizational commitment was 3.07. There were significant correlations among self-leadership, team trust and organizational commitment. Self-leadership had significant correlation with team trust (r=.25, p<.001). Also, self-leadership (r=.34, p<.001) and team trust (r=.31, p<.001) showed significant correlation with organizational commitment. In stepwise multiple regression analysis, age, self-leadership and team trust were included in the factors affecting organizational commitment of clinical nurses. These variables explained 20% of organizational commitment. Conclusion: The results confirmed that nurses' self-leadership and team trust affects significant influences on organizational commitment. Accordingly, in order to enhance nurses' organizational commitment, it is necessary to build effective strategies to enhance self-leadership and team trust for nurses. Such strategies will be able to improve the goal achievement of nursing unit.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1992년도 하계학술대회 논문집 A
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• pp.89-92
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• 1992

This paper presents an approach for thermal Unit Commitment by Lagrangian Relaxation with fuzzy technique. A proposed algorithm makes it possible to execute optimal decision making between Generation Cost and Load Demand with membership function. In order to test the validity of the proposed method, we applied to Mid-westerm utility system which has 20 thermal units. So, the usefulness of this method is verified.

• 한국정보과학회논문지:소프트웨어및응용
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• 제29권9호
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• pp.645-653
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• 2002

발전기 기동정지 계획은 하나의 전력시스템을 형성하는 다수의 발전기에 대해서 주어진 여러 제약을 따르는 일간 또는 주간의 기동 및 정지시간을 결정하는 작업으로 다양한 제약과 방대한 탐색공간으로 인해 최적의 경제적 계획 수립이 매우 어려운 대규모 최적화 문제이다. 타부 탐색은 보통의 지역적 탐색법에 비해 국지적 최적해에 빠질 위험이 적고 다른 전역적 탐색기법에 비해 대상문제에 관한 지식을 충분히 활용하기에 유리하여 많은 최적화 문제에 사용되고 있다. 그러나 규모가 방대하면서 많은 제약조건이 존재하는 대규모 최적화 문제들은 타부 탐색으로도 빠른 시간내에 최적의 해를 찾아내기 힘들다. 본 논문은 대규모 최적화 문제의 하나인 발전기 기동정지 계획 문제를 타부 탐색의 병렬화를 통해 해결함으로써 탐색 소요시간의 단축과 함께 해의 질 또한 향상시킬 수 있음을 보여준다.

• 중환자간호학회지
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• 제15권1호
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• pp.58-68
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• 2022

Purpose : This study aimed to provide basic data for developing strategies to improve the nursing performance of nurses working in the intensive care unit by identifying the degree of their communication ability, job satisfaction, organization commitment, and nursing performance, and the relation between each of these variables in the intensive care unit by examining the factors affecting nursing performance. Methods : The participants comprised of 150 nurses working in the intensive care unit in two advanced general hospitals. Data were collected using structured questionnaires and analyzed using a t-test, ANOVA, the Scheffé test, Pearson's correlation coefficients, and multiple regression analysis using the SPSS/WIN 25.0 program. Results : Nursing performance of the participants was positively correlated with communication ability (r=.64, p<.001), job satisfaction (r=.26, p<.001), and organization commitment (r=.29, p<.001). Factors significantly influencing the participants' nursing performance included academic background (𝛽=.16, p=.032) and communication ability (𝛽=.50, p<.001). The explanatory power of these variables for nursing performance was recorded at 49.9% (F=19.04, p<.001). Conclusion : The use of various programs in the hospital and the development of effective communication ability with medical staff and other departments among nurses will help improve nursing performance, cooperation with other departments, and patient care.

• 대한전기학회논문지
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• 제33권10호
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• pp.387-395
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• 1984

This paper proposes an improved unit commitment algorithm for the purpose of rational operation of electric power systems. Security function is introduced to consider generation system reliability as well as economical properties in the algotithm . As a stte model for assessment of state probabilities, the 3-state model in which the probability of the units for commitment can be considered is proposed and applied, so that the algorithm becomes more practical and reasonable one. A decision bounding scheme which can be applied to all kinds of system is described and the numerical results obtained for KEPCO and model systems are also presented to assure the availability of the proposed technique.

• 전기학회논문지
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• 제62권4호
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• pp.457-466
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• 2013

Wind energy is rapidly becoming significant generating technologies in electricity markets. As probabilistic nature of wind energy creates many uncertainties in the short-term scheduling, additional actions for reliable market operation should be taken. This paper presents a novel approach to evaluate ramping capability requirement for changes in imbalance energy between day-ahead market and real-time market due to uncertainty of wind generation as well as system load. Dynamic ramp rate model has been applied for realistic solution in unit commitment problem, which is implemented in day-ahead market. Probabilistic optimal power flow has been used to verify ramping capability determined by the proposed method is reasonable in economic and reliable aspects. This approach was tested on six-bus system and IEEE 118-bus system with a wind farm. The results show that the proposed approach provides ramping capability information to meet both forecasted variability and desired confidence level of anticipated uncertainty.

• Journal of Electrical Engineering and Technology
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• 제8권6호
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• pp.1596-1604
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• 2013

Coordinating operation between large-scale wind power and thermal units in multiple time scale is an important problem to keep power balance, especially for the power grids mainly made up of large coal-fired units. The paper proposes a novel operation mode of multi-scale unit commitment (abbr. UC) that includes mid-term UC and day-ahead UC, which can take full advantage of insufficient flexibility and improve wind power accommodation. First, we introduce the concepts of multi-scale UC and then illustrate the benefits of introducing mid-term UC to the wind-coal intensive grid. The paper then formulates the mid-term UC model, proposes operation performance indices and validates the optimal operation mode by simulation cases. Compared with day-ahead UC only, the multi-scale UC mode could reduce the total generation cost and improve the wind power net benefit by decreasing the coal-fired units' on/off operation. The simulation results also show that the maximum total generation benefit should be pursued rather than the wind power utilization rate in wind-coal intensive system.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 A
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• pp.337-340
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• 2000

In this paper, the effects of the uncertain hourly load demand are stochastically analyzed especially by the consideration of the average over generation of the Unit Commitment(UC) results. In order to minimize the effects of the actual load profile change, a new UC algorithm is proposed. The proposed algorithm calculates the UC results with the lower load level than the one generated by the conventional load forecast. In case of the worse load forecast, the deviation of the conventional UC solution can be overcome with the lower load level and the more hourly reserve requirements. The proposed method is tested with sample systems, which shows that the proposed method can be used as the basic guideline for selecting the potimal load forecast applying to UC problem.

• 한국직업건강간호학회지
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• 제26권2호
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• pp.105-113
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• 2017

Purpose: The purpose of this study was to identify the impact of workplace bullying experience and resilience on organizational commitment in general hospital nurses. Methods: Participants were 250 nurses of a general hospital in Seoul, Gyeonggi-do and Gangwoen-do. Data were collected using the structured questionnaires and analyzed using descriptive statistics, t-test, ANOVA, pearson's correlation coefficient, and multiple regression analysis. Results: As a result of multiple regression analysis, workplace bullying, resilience, clinical career, and work unit turned out to be variables that explained general hospital nurses' organizational commitment (Adj. $R^2=0.17$, p<.001). Conclusion: These findings suggest that bullying and resilience were defined as the influential variables on organizational commitment of nurses. Therefore strategies and programs about workplace bullying and resilience are needed to be developed.