• 한국정보통신학회논문지
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• 제27권1호
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• pp.135-138
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• 2023

In this paper, we study real-time error in the context of monitoring a binary information source through a delay system. To derive the average real-time error, we model the delay system as a discrete time Geo/D/1/1 queueing model. Using a discrete time three-dimensional Markov chain with finite state space, we analyze the queueing model. We also perform some numerical analysis on various system parameters: state transition probabilities of binary information source; transmission times; and transmission frequencies. When the state changes of the information source are positively correlated and negatively correlated, we investigate the relationship between transmission time and transmission frequency.

• 한국시뮬레이션학회논문지
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• 제17권4호
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• pp.219-227
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• 2008

DEVS 형식론은 이산 사건 시스템을 계층적이고 모듈러하게 표현할 수 있다. MATLAB/Simulink는 연속 시스템과 이산 시간 시스템을 모델링하고 시뮬레이션을 수행하는 데 널리 쓰인다. 본 논문은 MATLAB/Simulink 환경에서 DEVS 형식론을 구현하는 방법론을 제안한다. 본 논문에서 제안하는 방법론을 이용하여MATLAB/Simulink에서 제공하는 다양한 공학 방정식과 알고리즘을 사용할 수 있다. 또한 동일한 시뮬레이션 환경에서 연속 시스템과 이산 사건 시스템이 혼합된 하이브리드 시스템에 대한 시뮬레이션을 수행할 수 있다. 이를 위해 본 논문은 Simulink-DEVS 모델과 이 모델을 시뮬레이션을 수행하는 데 필요한 시간 진행 알고리즘을 제안한다. 특히 시간 진행 알고리즘은 시스템의 유형에 상관없이 적절한 시간 진행을 수행한다. 두 가지 실험 결과를 통해 본 논문에서 제안하는 방법론의 효용성을 입증한다.

• 전기의세계
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• 제29권11호
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• pp.742-750
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• 1980

The problem of nonlinear time-invariant system identification by estimation of Wiener kernels is studied for discrete time systems with inputs having symmetric probability distributions. G-functionals are constructed. It is further shown that under idealized conditions, these seemingly different techniques yield the same results. The results of identification of asimulated second degree system is presented.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1987년도 한국자동제어학술회의논문집; 한국과학기술대학, 충남; 16-17 Oct. 1987
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• pp.223-227
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• 1987

This paper presents the extended interaction prediction method for large scale discrete-time systems with interconnected state and control. Feedback gain is obtained from decentralized calculation without solving Riccati equation. Hence, Computer storage and calculation time is reduced.

• 한국산업정보학회논문지
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• 제22권1호
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• pp.23-32
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• 2017

본 논문에서는 이산시간 마코비안 도착과정(discrete-time Markovian arrival process, 이하 이산시간 MAP)을 갖는 대기행렬시스템의 주요성능척도들을 분석하기 위한 통합적 접근방법을 제시한다. 기존의 이산시간 MAP/G/1 대기행렬시스템의 연구들을 보면 동일한 시스템에 대하여 시스템 내 고객수와 대기시간 등을 분석할 때 서로 다른 방법으로 접근하였기에 이 둘을 동시에 살펴보고자 할 때는 추가적인 시간과 노력이 뒤따랐다. 따라서 하나의 시스템을 여러 방면에서 포괄적으로 분석할 수 있는 통합적인 접근방법은 시스템을 설계하고 관리하는 입장에서 볼 때 중요한 분석의 틀이 된다. 본 논문에서는 이산시간 MAP/G/1 시스템의 안정상태 일량 분포를 유도하고 이를 이용하여 임의고객의 대기시간, 체재시간 분포를 유도한다. 체재시간 분포로부터 이탈시점 고객수 분포를 구하고 이탈시점 고객수와 임의시점 고객수와의 관계로부터 고객수 분포를 유도한다.

• 대한수학회지
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• 제52권4호
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• pp.797-819
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• 2015

A trapdoor discrete logarithm group is a cryptographic primitive with many applications, and an algorithm that allows discrete logarithm problems to be solved faster using a pre-computed table increases the practicality of using this primitive. Currently, the distinguished point method and one extension to this algorithm are the only pre-computation aided discrete logarithm problem solving algorithms appearing in the related literature. This work investigates the possibility of adopting other pre-computation matrix structures that were originally designed for used with cryptanalytic time memory tradeoff algorithms to work as pre-computation aided discrete logarithm problem solving algorithms. We find that the classical Hellman matrix structure leads to an algorithm that has performance advantages over the two existing algorithms.

• Journal of Electrical Engineering and Technology
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• 제9권5호
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• pp.1551-1561
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• 2014

Design, Simulation and experimental analysis of closed loop time domain based Discrete PWM buck-boost converter are described. To improve the transient response and dynamic stability of the proposed converter, Discrete PID controller is the most preferable one. Discrete controller does not require any precise analytical model of the system to be controlled. The control system of the converter is designed using digital PWM technique. The proposed controller improves the dynamic performance of the buck-boost converter by achieving a robust output voltage against load disturbances, input voltage variations and changes in circuit components. The converter is designed through simulation using MATLAB/Simulink and performance parameters are also measured. The discrete controller is implemented, and design goal is achieved and the same is verified against theoretical calculation using LabVIEW.

• 소음진동
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• 제10권3호
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• pp.451-456
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• 2000

In this paper a discrete time model for the identification of nonlinear vibration system with stick-slip friction is proposed. The proposed model can handle the highly nonlinear behavior of the friction such as stick-slip phenomenon and Stribeck effect. The basic idea of the proposed model is as follows : If the nonlinearity of the system can be predicted as a simple function then this nonlinear function term cab be directly used in the discrete time model. By doing this the number of nonlinear terms in the model can be much less than those of NARMAX model which is widely used nonlinear discrete model. The simulation result shows that the proposed model can estimate the response of the nonlinear vibration system with stick-slip friction very well with less computational effort.

• 전기학회논문지
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• 제61권3호
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• pp.466-471
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• 2012

In this paper, we consider the problem of a robust passive filtering with low-order for discrete-time singular systems with polytopic uncertainties. A BRL(bounded real lemma) for robust passivity with a dissipativity of discrete-time uncertain singular systems is derived. A low-order robust passive filter design method is proposed by new reduced-order method and LMI(linear matrix inequality) technique on the basis of the obtained BRL. Finally, illustrative examples are presented to show the applicability of the proposed method.

• 드라이브 ㆍ 컨트롤
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• 제14권4호
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• pp.23-28
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• 2017

Time-delay control with internal model (TDCIM) is the controller for robot manipulators that applies the time-delay estimation and the concept of internal model control (IMC). TDCIM is robust against unknown dynamics and non-linear friction like coulomb friction and static friction. It is simple and computationally efficient. This study presents the relationship between the discrete TDCIM and the discrete PID controller. The PID controller is the most popular control law in the real application. But often the PID controller can be difficult to achieve the desired level of control performance. The result in this study provides a good candidate solution to these situations.