• KSII Transactions on Internet and Information Systems (TIIS)
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• 제4권4호
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• pp.452-474
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• 2010

Formidable growth of Internet technologies has revealed challenging issues about its scale and performance evaluation. Modeling and simulation play a central role in the evaluation of the behavior and performance of the large-scale network systems. Large numbers of nodes affect simulation performance, simulation execution time and scalability in a weighty manner. Most of the existing simulators have numerous problems such as size, lack of system theoretic approach and complexity of modeled network. In this work, a scalable discrete-event modeling approach is described for studying networks' scalability and performance traits. Key fundamental attributes of Internet and its protocols are incorporated into a set of simulation models developed using the Discrete Event System Specification (DEVS) approach. Large-scale network models are simulated and evaluated to show the benefits of the developed network models and approaches.

• Journal of applied mathematics & informatics
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• 제9권1호
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• pp.61-76
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• 2002

The robust non-fragile guaranteed cost control problem is studied in this paper for class of uncertain linear large-scale systems with time-varying delays in subsystem interconnections and given quadratic cost functions. The uncertainty in the system is assumed to be norm-hounded arid time-varying. Also, the state-feedback gains for subsystems of the large-scale system are assumed to have norm-bounded controller gain variations. The problem is to design state feedback control laws such that the closed-loop system is asymptotically stable and the closed-loop cost function value is not more than a specified upper bound far all admissible uncertainties. Sufficient conditions for the existence of such controllers are derived based on the linear matrix inequality (LMI) approach combined with the Lyapunov method. A parameterized characterization of the robust non-fragile guaranteed cost contrellers is 7iven in terms of the feasible solution to a certain LMI. Finally, in order to show the application of the proposed method, a numerical example is included.

• Molecules and Cells
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• 제39권6호
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• pp.439-446
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• 2016

Clearing and labeling techniques for large-scale biological tissues enable simultaneous extraction of molecular and structural information with minimal disassembly of the sample, facilitating the integration of molecular, cellular and systems biology across different scales. Recent years have witnessed an explosive increase in the number of such methods and their applications, reflecting heightened interest in organ-wide clearing and labeling across many fields of biology and medicine. In this review, we provide an overview and comparison of existing clearing and labeling techniques and discuss challenges and opportunities in the investigations of large-scale biological systems.

• 한국지능시스템학회논문지
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• 제21권5호
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• pp.549-554
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• 2011

본 논문에서는 출력 궤환 제어기를 이용해 다항식 퍼지 대규모 시스템을 안정화하는 방법을 제안한다. 이를 위해, 먼저, 대규모 시스템의 부분 시스템에 대해 퍼지 모델링을 한 후, 각각에 대해 출력 궤환 제어기를 설계하여 대규모 시스템을 안정화하는 방법을 제안한다. 이때, 다항식 Lyapunov 함수를 적용하면 다항식 퍼지 대규모 시스템의 안정화 조건은 제곱합 조건으로 주어지고, 이것은 MATLAB의 툴박스인 SOSTOOLS로 해석 가능하다. 이러한 과정을 거친 후에 얻어진 해에서 시스템을 안정화시키는 출력 궤환 제어기의 이득을 구할 수 있다. 마지막으로, 제안된 기법의 적합성을 검증하기 위해 시뮬레이션 예제가 주어진다.

• 한국ITS학회 논문지
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• 제13권3호
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• pp.1-9
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• 2014

본 연구는 대형 이벤트가 발생하였을 때 신속하고 정확한 교통정책을 수립할 수 있도록 대형 이벤트 대응형 통합교통분석 시스템을 개발하는 데 목적이 있다. 교통분석 시스템 사례조사를 기초로 통합교통분석 시스템의 요건을 정의하고 개발방향을 수립하였다. 데이터 웨어하우스 (data warehouse) 구축을 위해 신속하고 정확한 교통정책 수립이 요구되는 대형 이벤트를 선정하고 데이터를 수집하였다. 수집된 대형 이벤트 데이터와 교통 데이터를 통합하여 데이터 웨어하우스와 주제별 데이터 마트 (data mart)를 구축하였다. 이용자가 적시에 의사결정을 할 수 있도록 비즈니스 인텔리전스(business intelligence) 시스템 화면을 설계하고 개발하였다.

• 대한전자공학회논문지
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• 제24권1호
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• pp.46-51
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• 1987

Using the computer-generated Lyapunov functions due to Brayton-tong's constructive algorithm, we estimate the domains of attraction of dynamical systems of the second order, and analyze the asymptotic stability of large scale contincous-time and discrete-time systems by the decomposition and aggregation method. With this approach we get the less conservative stability results than the existing methods.

• International Journal of Control, Automation, and Systems
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• 제5권5호
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• pp.526-538
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• 2007

This paper presents a neural network based decentralized excitation controller design for large-scale power systems. The proposed controller design considers not only the dynamics of generators but also the algebraic constraints of the power flow equations. The control signals are calculated using only local signals. The transient stability and the coordination of the subsystem control activities are guaranteed through rigorous stability analysis. Neural networks in the controller design are used to approximate the unknown/imprecise dynamics of the local power system and the interconnections. All signals in the closed loop system are guaranteed to be uniformly ultimately bounded. To evaluate its performance, the proposed controller design is compared with conventional controllers optimized using particle swarm optimization. Simulations with a three-machine power system under different disturbances demonstrate the effectiveness of the proposed controller design.

• Journal of Electrical Engineering and Technology
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• 제11권3호
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• pp.724-732
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• 2016

In this paper, a sampled-data observer-based decentralized fuzzy control technique is proposed for a class of nonlinear large-scale systems, which can be represented to a Takagi-Sugeno fuzzy system. The premise variable is assumed to be measurable for the design of the observer-based fuzzy controller, and the closed-loop system is obtained. Based on an exact discretized model of the closed-loop system, the stability condition is derived for the closed-loop system. Also, the stability condition is converted into the linear matrix inequality (LMI) format. Finally, an example is provided to verify the effectiveness of the proposed techniques.

• 대한전기학회논문지:시스템및제어부문D
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• 제49권1호
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• pp.26-32
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• 2000

In this paper, we consider to robust controller design problem for the linear large scale systems with the uncertainties and the time-delays. The considered time-delays are that exist in the state and the input of the subsystems and the interconnected subsystems. And the considered uncertainties are two general types that exist in the system, input and interconnected matrices. Based on the linear matrix inequality(LMI) and Lyapunov theorem, we present sufficient conditions for the existence of a controller that guarantees the asymptotic stability of systems regardless of the uncertainties and the time-delays. Also, the controller can be easily obtained by checking the feasibility of the LMI's. Finally, we show the usefulness of our results by an example.

• 센서학회지
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• 제26권1호
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• pp.1-6
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• 2017

The advanced driver assistant system (ADAS) requires the collection of a large amount of information including road conditions, environment, vehicle status, condition of the driver, and other useful data. In this regard, large-scale sensor networks can be an appropriate solution since they have been designed for this purpose. Recent advances in sensor network technology have enabled the management and monitoring of large-scale tasks such as the monitoring of road surface temperature on a highway. In this paper, we consider the estimation and fusion problems of the large-scale sensor networks used in the ADAS. Hierarchical fusion architecture is proposed for an arbitrary topology of the large-scale sensor network. A robust cluster estimator is proposed to achieve robustness of the network against outliers or failure of sensors. Lastly, a robust hierarchical data fusion scheme is proposed for the communication channel between the clusters and fusion center, considering the non-Gaussian channel noise, which is typical in communication systems.