• Journal of the Korean Data and Information Science Society
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• 제15권3호
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• pp.575-584
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• 2004

We propose a Bayesian model-based approach using a mixture of Dirichlet processes model with discrete wavelet transform, for curve clustering in the microarray data with time-course gene expressions.

• 한국시뮬레이션학회논문지
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• 제13권4호
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• pp.1-16
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• 2004

The modelling and simulation of the activation process for the heart system is meaningful to understand special excitatory and conductive system in the heart and to study cardiac functions because the heart activation conducts through this system. This thesis proposes two dimensional cellular automaton(CA) model for the activation process of the myocardium and conducted simulation by means of discrete time and discrete event algorithm. In the model, cells are classified into anatomically similar characteristic parts of the heart and each of cells has a set of cells with preassigned properties. Each cell in this model has state variables to represent the state of the cell and has some state transition rules to change values of state variables executed by state transition function. The state transition rule is simple as follows. First, the myocardium cell at rest stay in passive state. Second, if any one of neighborhood cell in the myocardium cell is active state then the state is change from passive to active state. Third, if cell's state is an active then automatically go to the refractory state after activation phase. Four, if cell's state is refractory then automatically go to the passive state after refractory phase. These state transition is processed repeatedly in all cells through the termination of simulation.

• Kyungpook Mathematical Journal
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• 제47권4호
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• pp.601-608
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• 2007

In this paper we introduce a discrete model of brucellosis happened in Korean livestock farms and numerically analyze its dynamical features. To do it, we consider parameters data supported by Livestock Cooperatives. To control brucellosis, we investigate the relationship among key parameters, as applications of our model. We hope that our model may be used to reduce brucellosis in Korean livestock farms.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 한국자동제어학술회의논문집(국내학술편); 포항공과대학교, 포항; 24-26 Oct. 1996
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• pp.569-572
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• 1996

Explicit state-space formulate for an H$_{.inf}$ based two-degrees-of-freedom robust controller are derived in discrete-time. The controller provides robust stability against coprime factor uncertainty, and a degree of robust performance in the sense of making the closed-loop system match a prespecified reference model. It is shown that the controller consists of a plant observer, the chosen reference model, and a generalized state feedback law associated with the plant and model states. The controller structure is shown to be relatively simple and thus may reduce the computational load on the digital control processor.

• International Journal of Naval Architecture and Ocean Engineering
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• 제4권3호
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• pp.211-227
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• 2012

To implement a combined discrete event and discrete time simulation such as submarine diving simulation in a distributed environment, e.g., in the High Level Architecture (HLA)/Run-Time Infrastructure (RTI), a HLA interface, which can easily connect combined models with the HLA/RTI, was developed in this study. To verify the function and performance of the HLA interface, it was applied to the submarine dive scenario in a distributed environment, and the distributed simulation shows the same results as the stand-alone simulation. Finally, by adding a visualization model to the simulation and by editing this model, we can confirm that the HLA interface can provide user-friendly functions such as adding new model and editing a model.

• International Journal of Fuzzy Logic and Intelligent Systems
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• 제8권2호
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• pp.151-157
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• 2008

A non-fragile guaranteed cost control (GCC) problem is presented for a class of discrete time-delay nonlinear systems described by Takagi-Sugeno (T-S) fuzzy model. The systems are assumed to have norm-bounded time-varying uncertainties in the matrices of state, delayed state and control gains. Sufficient conditions are first obtained which guarantee that the closed-loop system is asymptotically stable and the closed-loop cost function value is not more than a specified upper bound. Then the design method of the non-fragile guaranteed cost controller is formulated in terms of the linear matrix inequality (LMI) approach. A numerical example is given to illustrate the effectiveness of the proposed design method.

• 한국시뮬레이션학회논문지
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• 제22권2호
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• pp.11-19
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• 2013

본 논문에서는 전장 환경 요소 및 플랫폼 모델 간 상호 교환 정보를 통합하여 관리하는 전투 공간 모델(Battle Space Model)을 제안한다. 전투 공간 모델은 전장의 지형 정보와 환경 요소를 저장하는 Geographic Information System(GIS) Model, 플랫폼 모델 간 상호 교환 정보에 전장 환경 요소의 영향을 고려하는 Propagator Model, 플랫폼 모델 간 상호 교환 정보를 저장하는 Logger Model, 그리고 플랫폼 모델 간의 상호 작용(encounter) 시점을 예측하고 상호 작용 시점까지 시간을 건너뛰는 Spatial Encounter Predictor(SEP) Model로 구성된다. 또한 이산 사건 및 이산 시간 혼합형 시뮬레이션 모델 구조로 구성되어 있는 플랫폼 모델과 추가 작업 없이 직접 연결하기 위해, 전투 공간 모델 또한 이산 사건 및 이산 시간 혼합형 시뮬레이션 모델 구조로 구성하였다. 본 연구에서는 전투 공간 모델을 적용하여 수중운동체 교전 시뮬레이션을 수행하였다. 이를 통해 플랫폼 모델 각자가 반영하던 전장 환경 요소를 전투 공간 모델이 일괄적으로 반영함으로써 플랫폼 모델 개발을 단순화 할 수 있었다. 또한 각 플랫폼 모델은 다른 플랫폼 모델과의 정보 교환을 고려하지 않고 전투 공간 모델과의 정보 교환만을 고려하면 되므로, 플랫폼 모델을 중립적으로 구성할 수 있었다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 학술대회 논문집 정보 및 제어부문
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• pp.267-269
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• 2005

This paper describes a consideration on the sampling in linearly time-varying (LTV) systems in view of the convenience in digital signal processing. The relation between a continuous-time and a discrete-time system models is investigated for a simple linear time-invariant system. Based on the results of the investigation, we first consider discrete-time models for LTV systems, Then the simplicity of the models in terms of microprocessor-based digital signal processing is compared.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 하계학술대회 논문집 D
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• pp.1165-1167
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• 1997

In this paper, the continuous sliding mode-model following(SM-MF) power system stabilizer(PSS) including closed-loop feedback(CLF) is extended to discrete-time sliding mode-model following(DSM-MF) PSS including CLF.

• 제어로봇시스템학회논문지
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• 제10권2호
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• pp.112-124
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• 2004

A neural network based adaptive reconfigurable flight controller is presented for a class of discrete-time nonlinear flight systems in the presence of variations of aerodynamic coefficients and control effectiveness decrease caused by control surface damage. The proposed adaptive nonlinear controller is developed making use of the backstepping technique for the angle of attack, sideslip angle, and bank angle command following without two time separation assumption. Feedforward multilayer neural networks are implemented to guarantee reconfigurability for control surface damage as well as robustness to the aerodynamic uncertainties. The main feature of the proposed controller is that the adaptive controller is developed under the assumption that all of the nonlinear functions of the discrete-time flight system are not known accurately, whereas most previous works on flight system applications even in continuous time assume that only the nonlinear functions of fast dynamics are unknown. Neural networks learn through the recursive weight update rules that are derived from the discrete-time version of Lyapunov control theory. The boundness of the error states and neural networks weight estimation errors is also investigated by the discrete-time Lyapunov derivatives analysis. To show the effectiveness of the proposed control law, the approach is i]lustrated by applying to the nonlinear dynamic model of the high performance aircraft.