• International Journal of Fuzzy Logic and Intelligent Systems
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• v.1 no.1
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• pp.113-118
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• 2001

In this paper, we develop an optimal intelligent digital redesign method for a class of fuzzy-model-based controllers, effective for stabilization of continuous-time complex nonlinear systems. Takagi-Sugeno (TS) fuzzy model is used to extend the results of the classical digital redesign technique to complex nonlinear systems. Unlike the conventional intelligent digital redesign technique reported in the literature, the proposed method utilized the recently developed LMI optimization technique to obtain a digitally redesigned fuzzy-model-based controller. Precisely speaking, the intelligent digital redesign problem is converted to an equivalent optimization problem, and the LMI optimization method is used to find the digitally redesigned fuzzy-model-based controller. A numerical example is provided to evaluate the feasibility of the proposed approach.

• Proceedings of the KIEE Conference
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• 2002.07a
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• pp.232-234
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• 2002

A Vacuum Circuit Breaker Model for simulation of transient overvoltages was developed by using the PSCAD/EMTDC. The Model includes the power frequency chopping current. Breaker withstand voltage, and quenching capability of High frequency currents. To verify the abilities of the breaker model, the simulation on the Lindmayer's single-phase circuit was carried out. The results show that using the proposed model, the transient overvoltages, current chopping, and multiple reignitions of vacuum breaker are properly reproduced as real phenomena. In further study, virtual chopping current will be incorporated into the model for 3 phase system.

• Asia pacific journal of information systems
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• v.16 no.2
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• pp.69-84
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• 2006

Importance of Today's diffusion of integrated hospital information systems is that various and huge amount of data is being accumulated in their database systems. Many researchers have studied utilizing such hospital data. While most researches were conducted mainly for medical diagnosis, there have been insufficient studies to develop medical care cost prediction model, especially using machine learning techniques. In this research, therefore, we built a medical care cost prediction model for cancer patients using CBR (Case-Based Reasoning), one of the machine learning techniques. Its performance was compared with those of Neural Networks and Decision Tree models. As a result of the experiment, the CBR prediction model was shown to be the best in general with respect to error rate and linearity between real values and predicted values. It is believed that the medical care cost prediction model can be utilized for the effective management of limited resources in hospitals.

• Journal of Korea Society of Digital Industry and Information Management
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• v.10 no.3
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• pp.61-70
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• 2014

The government supports the various systems on the premise of life-long education for improving the qualification of its people and supporting the lifelong career system. These systems help the educational activities for every generation from the teens. Each government department supports the learning activities for those who are related. In addition, each government department systemizes the regular education for advancing the performance of civil servant, by obliging a self-directed system to their member as well as by reflecting this educational activities in a promotion. This style of learning is provided not only offline but also online. However, not all necessary educational contents is furnished within the department. It is sometimes necessary to cooperate with the commissioned education and a professional educational institution. This thesis suggests three model systems while comparing one another. This paper suggests three system model. The first model is e-contents open place. The second model is e-contents open place. Finally, the suggest model is mixed form.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.33 no.5
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• pp.447-454
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• 2009

Rate-independent crystal plasticity model suffers from the non-uniqueness of activated slip systems and the determination of the shear slip rates on the active slip systems. In this paper, a time-integration algorithm which circumvents the problem of the multiplicity of the slip systems was developed and implemented into the user subroutine VUMAT of a commercial finite element program ABAQUS. The magnitude of the slip shears on the active slip systems in f.c.c Cu single crystal aligned with the specific crystallographic orientation was investigated to validate our solution procedure. Also, texture developments under various deformation modes such as simple compression, simple tension and plane strain compression were compared with the results of the rate-dependent model by using the rate-independent crystal plasticity model. The computation time employing the rate-independent model is much more reduced than the those of the rate-dependent model.

• The Journal of Society for e-Business Studies
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• v.2 no.2
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• pp.55-74
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• 1997

In this paper, the concept of coordination under the setting of cooperative multiagent systems is examined. Based on the concept, a computational model in which the key constructs of coordination can be precisely defined is developed. This model can serve as a basis for developing software systems designed to support coordination in Eletronic Commerce. Coordination is viewed as management of conflicting demands on finite resources by actors or acitivities. The model views coordination as a cycle of four phases: the definition phase, the conflict resolution phase, the action phase, and the adaptation phase. Then, a formal model of coordination, both as a phenomenon and as a process is devloped. Within the context of this model, important concepts such as decomposability, informational privacy, informational decentralization, and informational efficiency are examined.

• Journal of the Korean Institute of Intelligent Systems
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• v.16 no.2
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• pp.144-149
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• 2006

This paper deals with a balanced model reduction for uncertain nonlinear systems via T-S fuzzy approach. We define a generalized controllability/observability gramian and obtain a balanced state space model using generalized gramians which can be obtained from solutions of linear matrix inequalities. We present a balanced model reduction scheme by truncating not only state variables but also uncertain elements. An upper bound of the model reduction error will also be suggested. In order to demonstrate the efficacy of our method, a numerical example will be presented.

• Transactions of the Korean Society of Automotive Engineers
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• v.21 no.2
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• pp.159-165
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• 2013

ESD damage by Charged Cable Model (CCM) is introduced. Due to its own impedance characteristic unlike Human Body Model (HBM) or Machine Model (MM) electric component can be destroyed even though it is located after typical protection circuit. Possible mechanism of ESD damage to automotive electric control unit (ECU) in vehicle environment by CCM discharge was investigated. Based on investigation, field-returned vehicle whose ECU is expected to be damaged by CCM discharge was tested to reproduce it and similar electric component destruction inside ECU was observed. Suggestions to reduce the possibility of ESD damage by CCM are introduced.

• IE interfaces
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• v.19 no.1
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• pp.9-18
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• 2006

In this paper, we explore the ubiquitous system that provides new business opportunities in the context of digital convergence. Exploiting the value network of the proposed ubiquitous system, we analyze strategic market drivers that define the speed and direction of the evolution path for ubiquitous industries. Motivated by the dynamic growth of ubiquitous industry, we design a set of ubiquitous business models that pave the way for firms to identify profitable business cases. In addition, we analyze the evolution path of the proposed business model such that the model can be implemented in the life-cycle of ubiquitous industry. Futhermore, we develop a modeling framework for selecting a suitable business model and for evaluating the performance of the selected business model.

• Journal of Korean Institute of Industrial Engineers
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• v.42 no.2
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• pp.86-95
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• 2016

We propose a new approach to the stochastic version of Lanchester model. Commonly used approach to stochastic Lanchester model is through the Markov-chain method. The Markov-chain approach, however, is not appropriate to high dimensional heterogeneous force case because of large computational cost. In this paper, we propose an approximation method of stochastic Lanchester model. By matching the first and the second moments, the distribution of each unit strength can be approximated with multivariate normal distribution. We evaluate an approximation of discrete Markov-chain model by measuring Kullback-Leibler divergence. We confirmed high accuracy of approximation method, and also the accuracy and low computational cost are maintained under high dimensional heterogeneous force case.