• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2001.12a
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• pp.91-94
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• 2001

In the frequency response analysis using a modal method, it is very important to determine the number of modes involved with the formulation of a frequency response function. Most engineers are inclined to determine mode truncation with their experience. But it is difficult for non-experts to decide the mode truncation reasonably in many problems of dynamic analyses. In this study, fuzzy theory is used to standardize the empirical determination of mode truncation so that not only the experts but also non-experts can decide a proper mode truncation easily. Fuzzy rule base is based on the simulation results using finite element method. Numerical simulations show that the developed mode truncation method is a very effective method to choose the number of the considered modes.

• Proceedings of the KIEE Conference
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• 2003.11b
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• pp.127-130
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• 2003

In this paper, a hypothesis in order that the impulse response of a stable linear system does not change sign is suggested. For fixed zeros of the systems, the problem of synthesizing such a system is reduced to the problem of finding a proper denominator polynomial so that the step response of the overall system will not overshoot. The hypothesis is associated with the generalized time constant by Kim[5]. Under the hypothesis, we propose several methods that allow to compose a continuous time LTI systems achieving non-negative impulse response.

• Journal of Korean Library and Information Science Society
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• v.24
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• pp.81-106
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• 1996

Without an accurate understanding of information needs of library users, an efficient services can't be implement. And we can expect that there is a difference between query statement and actual information needs of users. It also will occur difference in the process of librarian's interpretation of query statement because of an inaccurate presentation and their different working experiences. It means that there is a communication problems between users and librarians. The purpose of this study is to provide the techniques of face to face communication between users and librarians as a method of efficient library service activities. And focused on the importance of non-language communication. The effectiveness of this study are as follows: 1. With the understanding of information flow, librarians can expand the extent of library services. 2. Knowing that how to communicate with users at the a n.0, ppropriate degree, librarians can improve the communication techniques. 3. Expanding the satisfaction of information services and heitening the reliability of users. 4. From the analysis of user information needs, librarians can convert present system to the proper service-oriented system. 5. Knowing the importance of non-language communication, librarians can improve the service environment.

• Journal of the Korean Operations Research and Management Science Society
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• v.33 no.2
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• pp.1-16
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• 2008

The purpose of this paper is to propose a new binary classification method for predicting corporate failure based on genetic algorithm, and to validate its prediction power through empirical analysis. Establishing virtual companies representing bankrupt companies and non-bankrupt ones respectively, the proposed method measures the similarity between the virtual companies and the subject for prediction, and classifies the subject into either bankrupt or non-bankrupt one. The values of the classification variables of the virtual companies and the weights of the variables are determined by the proper model to maximize the hit ratio of training data set using genetic algorithm. In order to test the validity of the proposed method, we compare its prediction accuracy with ones of other existing methods such as multi-discriminant analysis, logistic regression, decision tree, and artificial neural network, and it is shown that the binary classification method we propose in this paper can serve as a premising alternative to the existing methods for bankruptcy prediction.

• 한국전산유체공학회:학술대회논문집
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• 2001.05a
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• pp.72-77
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• 2001

The computational efficiency of an shape optimization procedure is highly dependent upon the proper selection of shape representation methods and design variables. In this study, shape functions, Bezier and NURBS(non-uniform rational B-splines) curves are selected as configuration generation methods and their efficiencies on the nose shape design of high-speed air vehicles, are compared. The effects of the number of control points, weighting factors and the optimization methods when utilizing the NURBS curves, are investigated. By implementing Bezier and NURBS curves, shapes having lower drag than the optimization case utilizing the shape functions, were obtained, hence it was demonstrated that these curves have better capability in representing the configuration. Efforts will be given to improve the convergence behavior when utilizing the NURBS, hence to reduce the number of Navier-Stokes analysis calculations.

• Management Science and Financial Engineering
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• v.16 no.3
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• pp.95-102
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• 2010

This paper considers the robust inventory control problem introduced by Bertsimas and Thiele [4]. In their paper, they have shown that the robust version of the inventory control problem can be solved by solving a nominal inventory problem which is formulated as a mixed integer program. As a proper generalization of the model, we consider the problem with non-stationary cost. In this paper, we show that the generalized version can also be solved by solving a nominal inventory problem. Furthermore, we show that the problem can be solved efficiently.

• The Journal of Korean Medicine
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• v.21 no.4
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• pp.271-275
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• 2000

A growing number of people are concerned about their sleep. There are many people with chronic sleep disorders. As there are various causes in a disease, proper treatment according to each cause is necessary for a more effective treatment. In general, insomnia is classified into five categories of physical, physiological, psychological, psychiatric and pharmacological aspects. Sedative-hypnotics including benzodiazepine and non-benzodiazepine have widely been used in chronic insomniacs. However, most hypnotics including non-benzodiazepine cause some of dependence, tolerance, impaired daytime function and rebound insomnia. Therefore, we are looking forward to proposing an effective oriental treatment for insomnia. A 71-year-old male who had suffered from cerebral infarction was admitted to our department for oriental treatment of stroke and insomnia. Initial treatment modalities with administration of paroxetine were not effective. However administration of oriental medicine' Gochimmuwoo-san(Gaozhenwuyou-san)' achieved a desirable effect.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2005.10a
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• pp.3-9
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• 2005

The recent notion of Network Centric Warfare (NCW) emphasizes the ability to distribute right information at the right time to maximize the combat effectiveness. Accordingly, in the modern combat system the importance of non-physical element, such as communication system is increasing. However, an NCW-support communication network system is expensive. Therefore, it is essential to develop a proper combat system evaluation method to establish an efficient NCW-support combat system. Traditionally, combat system effectiveness is measured in terms of physical elements such as men and fire power. Obviously, such method is hardly applicable to a modern combat system To overcome this difficulty, we propose an evaluation model based on CA (Cellular Automata) simulation. A set of preliminary combat simulations show that CA simulation may be promising in evaluating non-physical element of a modem combat system.

• Transactions of Materials Processing
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• v.14 no.9 s.81
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• pp.751-755
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• 2005

This paper is concerned with spring back after sheet forming of bulk amorphous alloys in the super cooled liquid state. The temperature-dependence and strain-rate dependence of Newtonian/non-Newtonian viscosities as well as the stress overshoot/undershoot behavior of amorphous alloys are reflected in the thermo-mechanical Finite Element simulations. Hemispherical deep drawing operations are simulated for various forming conditions such as punch velocity, die comer radius, friction, blank holder force, clearance and initial funning temperature. Here, spring back by an instantaneous elastic unloading was followed by thermal deformation during cooling, and two modes of spring back are examined in detail. It could be concluded that the superior sheet formability of an amorphous alloy can be obtained by taking the proper forming conditions for loading/unloading.

• Journal of the Korean Society for Precision Engineering
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• v.19 no.12
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• pp.33-37
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• 2002

A short shot is a molded part that is incomplete because insufficient material was injected into the mold. Remedial actions to control the process conditions can be taken by the injection molding experts based on their knowledge and experience. However, it is very difficult for the non-experts to avoid short shot by finding the proper process conditions such as mold temperature, melt temperature and filling time. In this paper, an intelligent generator of the optimal process conditions based upon fuzzy logic algorithm is proposed so that trial and error can be minimized and the non-experts as well as the experts can also find the optimal process conditions.