• Journal of the military operations research society of Korea
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• v.9 no.2
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• pp.11-22
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• 1983

The aim of this study is to minimize the total distance travelled by the examiners of college entrance examination committee, from their homes to the designated schools, such that the examiners are assigned to each school satisfying certain criteria. A network model is used and the Out-of-Kilter algorithm is applied to solve the examiner-examinee assignment problem. The result is proved to be fairly adequate not only in this problem, but also to the similar situations encountered in, say, school-grouping of junior/senior high schools, and an administration district allocation problem, etc.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 1993.06a
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• pp.1167-1170
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• 1993

We look at the problem of defuzzification in situations in which in addition to the usual fuzzy output of the controller there exists some ancillary restriction on the allowable defuzzified values. We provide two basic approaches to address this problem. In the first approach we enforce the restriction by selecting the defuzzified value through a random experiment in which the values which have nonzero probabilities are in the allowable region, this method is based on the RAGE defuzzification procedure and makes use of a nonmonotonic conjunction operator. The second approach which in the spirit of the commonly used methods, a kind of expected value, converts the problem to a constraint optimization problem.

• Journal of Korean Academy of Nursing
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• v.45 no.5
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• pp.671-683
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• 2015

Purpose: The purpose of this study was to understand and describe the leadership experience of clinical nurses. Methods: During 2014, data were collected using focus group interviews. Three focus group interviews were held with a total of 20 clinical nurses participating. All interviews were recorded as they were spoken and transcribed and data were analyzed using qualitative content analysis. Results: Fifteen categories emerged from the five main themes. 1) Thoughts on the leadership category: to lead others, to cope with problem situations adequately and to serve as a shield against difficulties. 2) Situations requiring leadership: situation that requires correct judgement, coping and situations that need coordination and cooperation. 3-1) Leadership behaviors: other-oriented approach and self-oriented approach. 3-2) Leadership behavior consequences: relevant compensation and unfair termination. 4-1) Facilitators of leadership: confidence and passion for nursing and external support and resources. 4-2) Barriers to leadership: non-supportive organization culture and deficiency in own leadership competencies. 5) Strategies of leadership development: strengthen leadership through self-development and organizational leadership development. Conclusion: In conclusion, the results indicate that it is necessary to enhance clinical nurses' leadership role in healthcare. Enhancement can be achieved through leadership programs focused on enlarging leadership experience, constant self-development, leadership training, and development of leadership competencies suited to the nursing environment.

• Communications of Mathematical Education
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• v.37 no.4
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• pp.569-590
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• 2023

The purpose of this case study is to compare and analyze the covariational reasoning levels of two middle school students revealed in the process of solving and generalizing algebra word problems. A class was conducted with two middle school students who had not learned quadratic equations in school mathematics. During the retrospective analysis after the class was over, a noticeable difference between the two students was revealed in solving algebra word problems, including situations where speed changes. Accordingly, this study compared and analyzed the level of covariational reasoning revealed in the process of solving or generalizing algebra word problems including situations where speed is constant or changing, based on the theoretical framework proposed by Thompson & Carlson(2017). As a result, this study confirmed that students' covariational reasoning levels may be different even if the problem-solving methods and results of algebra word problems are similar, and the similarity of problem-solving revealed in the process of solving and generalizing algebra word problems was analyzed from a covariation perspective. This study suggests that in the teaching and learning algebra word problems, rather than focusing on finding solutions by quickly converting problem situations into equations, activities of finding changing quantities and representing the relationships between them in various ways.

• Journal of the Korean Society for Library and Information Science
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• v.28
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• pp.247-266
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• 1995

The purpose of information retrieval is to help users solve their problems. To fulfill the purpose the user's problem needs to be focused on. The purpose of this study is to identify components and the structure of the user's problem in an academic research environment. From this study it was found that the scientific problem dealt within an academic environment is complicate and the problem is composed of 8 topical and 4 non-topical components. And they could be organized into a stucture. This study has three implications for user-oriented information retrieval. (1) The components and the structure of the problem need to be the framework for the effective information retrieval process and for the evaluation of information retrieval. (2) The research methodology used in this study can be applied to other information service situations and this will result in greater practical implication of a study for more effective information retrieval. And (3) for more effective user-oriented information retrieval, the user needs to be observed and studied in the actual' situation. This study showed that the complicate problem of the actual user can be studied in a systematic way and this resulted in important implications for information retrieval.

• Proceedings of the Korean Society for Quality Management Conference
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• 1998.11a
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• pp.277-286
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• 1998

This paper investigates the problem of determining optimal replacement policies for equipment subject to failures with cyclic rates. In many situations, the system failures depend on the operating environmental conditions that vary on time, usually with periodical manners. We use nonhomogeneous Poisson processes whose rate functions exhibit cyclic behavior as well as a long-term evolutionary trend to model the stochastic process of the failures when the rate of occurrence of the failures varies periodically, for example from day to day or between seasons. In this study, we compare optimal policies under the nonhomogeneous process with/without a cyclic component in the failure rate function. The analytical results for various situations are presented along with numerical examples using simulated data.

• Journal of The Korean Astronomical Society
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• v.37 no.5
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• pp.399-404
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• 2004

Cosmic rays are ubiquitous in space, and are apparently present wherever the matter density is small enough that they are not removed by collisions with ambient particles. The essential similarity of their energy spectra in many different regions places significant general constraints on the mechanisms for their acceleration and confinement. Diffusive shock acceleration is at present the most successful acceleration mechanism proposed, and, together with transport in Kolmogorov turbulence, can account for the universal specta. In comparison to shock acceleration, statistical acceleration, invoked in many situations, has significant disadvantages. The basic physics of acceleration and transport are discussed, and examples shown where it apparently works very well. However, there are now well-established situations where diffusive shock acceleration cannot be the accelerator. This problem will be discussed and possible acceleration mechanism evaluated. Statistical acceleration in these places is possible. In addition, a new mechanism, called diffusive compression acceleration, will be discussed and shown to be an attractive candidate. It has similarities with both statistical acceleration and shock acceleration.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2004.04a
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• pp.241-246
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• 2004

This paper proposed trajectory tracking control of mobile robot. Trajectory tracking control scheme are real coding genetic-algorithm and back-propergation algorithm. Control scheme ability experience proposed simulation. Stable tracking control problem of mobile robots have been studied in recent years. These studios have guaranteed stability of controller, but the performance of transient state has not been guaranteed. In some situations, constant gain controller shows overshoots and oscillations. So we introduce better control scheme using Real coding Genetic Algorithm(RCGA) and neural network. Using RCGA, we can find proper gains in several situations and these gains are generalized by neural network. The generalization power of neural network will give proper gain in untrained situation. Performance of proposed controller will verify numerical simulations and the results show better performance than constant gain controller.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.13 no.3
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• pp.126-132
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• 2004

This paper proposed trajectory tracking control based on genetic algorithm. Trajectory tracking control scheme are real coding genetic algorithm(RCGA) and back-propagation algorithm(BPA). Control scheme ability experience proposed simulation. Stable tracking control problem of mobile robots have been studied in recent years. These studies have guaranteed stability of controller, but the performance of transient state has not been guaranteed. In some situations, constant gain controller shows overshoots and oscillations. So we introduce better control scheme using real coding genetic algorithm and neural network. Using RCGA, we can find proper gains in several situations and these gains are generalized by neural network. The generalization power of neural network will give proper gain in untrained situation. Performance of proposed controller will verity numerical simulations and the results show better performance than constant gain controller.

• Journal of Institute of Convergence Technology
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• v.3 no.1
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• pp.41-44
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• 2013

Process and manufacturing data are numerously accumulated to the enterprise database in industries but little of those data are utilized. Data mining can support a decision to manager in process from the data. However, it is not easy to field managers because a proper adoption of various schemes is very difficult. In this paper, six scenarios are conducted using data mining schemes for the various situations of field claims such as yield problem, trend analysis and prediction of yield according to changes of operating conditions, etc. Scenarios, like templates, of various analysis situations are helpful to users.