• Journal of applied mathematics & informatics
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• 제17권1_2_3호
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• pp.361-377
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• 2005

A mathematical model dealing with a prey-predator system with disease in the prey is considered. The functional response of the predator is governed by a Hoilling type-2 function. Mathematical analysis of the model regarding stability and persistence has been performed. The effect of delay and diffusion on the above system is studied. The role of diffusivity on stability and persistence criteria of the system has also been discussed.

• Journal of applied mathematics & informatics
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• 제29권5_6호
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• pp.1381-1393
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• 2011

In this paper, we consider two-species periodic Gilpin-Ayala competition system with delay and impulsive effect. By using some analysis methods, sufficient conditions for the permanence of the system are derived. Further, we give the conditions of the existence and global asymptotic stable of positive periodic solution.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 ITC-CSCC -2
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• pp.1300-1303
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• 2002

In this paper, we consider how to treat delay-time uncertainties caused by inter-die and intradie variabilities in evaluating the distribution of the critical delay of a CMOS combinatorial circuit, and formulate inter-die variability as a correlation of delays. Then, we propose an algorithm to evaluate the distribution of the critical delay based on the algorithm in ［1] which takes correlations into account. We also show some experimental results to see the effect of the formulation.

• Journal of applied mathematics & informatics
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• 제28권5_6호
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• pp.1185-1202
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• 2010

In this paper, we have studied the dynamical behaviour such as boundedness, local and global stabilities, bifurcation of a single species population affected by environmental toxicant and population toxicant. We have also studied the effect of discrete delay of the environmental toxicant on the instantaneous growth rates of the population biomass and population toxicant due to incubation period. The length of delay preserving the stability is also estimated. Computer simulations are carried out to illustrate our analytical findings.

• 한국시뮬레이션학회논문지
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• 제8권2호
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• pp.101-109
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• 1999

In a commercial facsimile network system, a simulation analysis has been performed using ARENA due to the unavailability of theoretical models. The effect of a priority is compared with that of the current FCFS rule on the arriving call blocking rate and transmission time delay. The result shows that the priority rule reduces more service time delay as the arrival rate increases. A simulation analysis procedure is proposed to select optimal in/out port ratio at various hourly arrival rates with a given multiple-place transmission requests ratio.

• 한국산업정보학회:학술대회논문집
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• 한국산업정보학회 2002년도 춘계학술대회 논문집
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• pp.195-199
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• 2002

This paper describes the effect of substrate back bias of CMOS Inverter. When the substrate back bias applied in body, the MOS transistor threshold voltage increased and drain saturation current decreased. The back gate reverse bias or substrate bias has been widely utilized and the following advantage has suppressing subthreshold leakage, lowering parasitic junction capacitance, preventing latch up or parasitic bipolar transistor, etc. When the reverse voltage applied substrate, this paper stimulated the propagation delay time CMOS inverter.

• 센서학회지
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• 제7권1호
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• pp.23-30
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• 1998

본 논문에서는 전자광학추적기(Electro-Optical Tracking System:EOTS)에 사용되어지는 영상센서의 시간지연으로 인한 영향이 추적루프성능에 주는 영향을 분석하였다. 이에 대한 해결책으로 Smith예측기를 사용함으로서 시간지연을 가지는 시스템의 안정성과 각종성능지수를 향상시킬 수 있음을 모의실험을 통해 보였다. 또한 실제적인 유용성을 확인하기 위하여 최근 개발된 EOTS에 적용하여 그 유용성을 확인하였다.

• Journal of Electrical Engineering and Technology
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• 제12권3호
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• pp.1271-1279
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• 2017

A highly accurate model-free controller is proposed for trajectory tracking control of robot manipulators. The proposed controller incorporates time-delay estimation (TDE) to estimate and cancel continuous nonlinearities of robot dynamics, and exploits fuzzy logic systems to suppress the effect of the TDE error, which is due to discontinuous nonlinearities such as friction. To this end, integral sliding mode is defined using desired error dynamics, and a Mamdani-type fuzzy inference system is constructed. As a result, the proposed controller achieves the desired error dynamics well. Implementation of the proposed controller is easy because the design of the controller is intuitive and straightforward, and calculations of the complex robot dynamics are not required. The tracking performance of the proposed controller is verified experimentally using a 3-degree of freedom PUMA-type robot manipulator.

• 정보처리학회논문지C
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• 제13C권5호
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• pp.559-566
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• 2006

연결요청(connection request) 패킷의 전송비율을 일정 비율 이하로 제한함으로써 월 발생을 탐지하는 바이러스 쓰로틀링(virus throttling)은 대표적인 웜 조기 탐지 기술 중의 하나이다. 기존 바이러스 쓰로틀링은 비율 제한기의 주기를 고정시키고 지연 큐 길이를 감시하여 웜 발생 여부를 판단한다. 본 논문에서는 가중치 평균 지연 큐 길이를 적용하여 비율 제한기의 주기를 자율적으로 조절하는 알고리즘을 제안하고, 가중치 평균 지연 큐 길이에 따른 다양한 주기결정 기법을 제시한다. 실험결과 제안 알고리즘은 웜 탐지시간에는 크게 영향을 미치지 않으면서도 연결설정 지연시간을 단축하여 사용자가 느끼는 불편함을 줄여 줄 수 있음을 확인하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 하계학술대회 논문집 F
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• pp.2028-2032
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• 1997

When a high performance current control is desired, a computation time delay of a digital control system may deteriorate the control performance of a current controller. Such a non-negligible effect can be considerable in transient state. This paper deals with the modified predictive current control that compensates the time delay effects of a conventional predictive current control. The method is closely related to a local average current control and a symmetrical PWM pattern generation. Also some theoretical approaches are presented to describe the voltage saturation boundary of the power converter. For validation, the proposed method is applied to an active power filter system. The experimental results show considerable improvement in current tracking capability.