• Proceedings of the KSR Conference
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• 2007.05a
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• pp.928-931
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• 2007

In answer to the increase of demand for the safety in railroad, the safety activities are tried out. According to 'KORAIL Instruction number 2001-49', the project for developing Integrated Centralized Traffic Control Center has been carried out and the safety activities are guaranteed by documents named 'Safety Plan' and 'Safety Requirements' from this project. However the development system is not enough for the full safety activities. Therefore this paper we describes the relationship of safety activities and development systems and proposes the efficient direction of safety activities.

• Journal of the Institute of Convergence Signal Processing
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• v.13 no.3
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• pp.156-161
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• 2012

Random access protocol takes advantage of constructing a decentralized wireless network due to its intrinsic spectrum sensing capability. Such technical feature goes well with cognitive radio networks consisting of heterogeneous wireless systems, in which a centralized control between heterogeneous wireless systems is hard to be implemented. Motivated by the decentralized feature of the random access, we adopt the random access protocol in cognitive radio networks, and evaluate the performance of a CSMA-based cognitive radio network.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.9A
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• pp.1405-1412
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• 2000

In this paper, we propose an efficient dynamic wavelength assignment algorithm in distributed WDM (Wavelength-Division Multiplexing) networks without wavelength conversion. The algorithm tries to assign a locally-most-used wavelength distributedly on a fixed routing path. We first formulate our algorithm by using the concept of a sample space which consists of optical fibers connected to nodes on a routing path of a lightpath to be assigned a wavelength. In particular, we analyze the blocking performance mathematically as compared with that of the most-used (MU) wavelength assignment algorithm previously proposed for WDM networks under centralized control. We also obtain numerical results by simulation on the blocking performance of other centralized/distributed wavelength assignment algorithms as well as our algorithm using the M/M/c/c dynamic traffic model. Consequently, we show that analytical results match simulation results and that our algorithm is efficient in distributed WDM networks in terms of blocking performance, control traffic overhead and computation complexity.

• 제어로봇시스템학회:학술대회논문집
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• 1993.10a
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• pp.1147-1154
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• 1993

This paper introduces a case of SCADA System replacing from centralized processing system to distributed/open architecture system. The cons and pros of the distinctive two system configurations were studied and the requirements of new system that would be enable to easily follow 21 century's technical and operational inovation were presented.

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.32 no.4
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• pp.30-38
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• 2003

• 제어로봇시스템학회:학술대회논문집
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• 1989.10a
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• pp.183-187
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• 1989

This paper presents on approach to the position control of a robot manipulator by using a decentralized adaptive control scheme. The large scale system is regarded as the system which consists of many subsystems having interconnection. In each subsystem, a local control system is composed by feedforward and feedback component, one computes the nominal torque from the Newton-Euler equation, the other computes the perturbation equation which reduce the position error of the manipulator along the nominal trajectory. A computer simulation studies was conducted to evaluate and compare the performances of the proposed manipulator control scheme with those of the PD control and centralized control schemes.

• Journal of Institute of Control, Robotics and Systems
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• v.14 no.10
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• pp.983-990
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• 2008

This paper presents the fault detection and diagnosis(FDD) algorithm to enhance reliability of a longitudinal controller for an autonomous All-Terrain Vehicle(ATV). The FDD is designed to monitor and identify faults which may occur in distributed hardware used for longitudinal control, e.g., DSPs, CAN, sensors, and actuators. The proposed FDD is an integrated approach of decentralized and centralized FDD. While the former is processed in a DSP and suitable to detect faults in a single hardware, it is sensitive to noise and disturbance. On the other hand, the latter is performed via communication and it detects and diagnoses faults through analyzing concurrent performances of multiple hardware modules, but it is limited to isolate faults specifically in terms of components in the single hardware. To compensate for disadvantages of each FDD approach, two layered structure including both decentralized and centralized FDD is proposed and it allows us to make more robust fault detection and more specific fault isolation. The effectiveness of the proposed method will be validated experimentally.

• Management & Information Systems Review
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• v.2
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• pp.133-167
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• 1998

This article discusses the findings of an empirical study conducted on 62 large organizations. The major purpose of the study was to analyze the relationship of Information System Resources distribution between the system plan control and system development and system operation. In this study information system resource is broadly Identified by computer hardware, software, data, procedure, operator. Because of the real centralization/decentralization issue facing organizations is much broader then the choice between alternative computer hardware configurations. And there are three separate resources of the information system that can be decentralized system plan and control, system development, system operations. The decision regarding how to organize each of these three separate resources is based on a different set of criteria. Furthermore, each decision can be made relatively independently of the others. In this article the results of a study are indicated below. In the degree of decentralization of information system resources between system plan control and system development and system operations were found the positive relationship. Therefore, the more information system resources are decentralized in the one dimension, the more information system resources are decentralized in the other dimensions, and the more information system resources are centralized in the one dimension, the more information system resources are centralized in the other dimensions.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.15 no.6
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• pp.516-525
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• 1990

This paper proposes a hierarchical control algorithm for an efficient network management of a loosely-coupled system which consists of functional division and duplicating structure with a LAN to enhance reliability and availability. The algorithm is modeled using the Perti-net and verified with the reachability tree. Here, the proposed algorithm is compared with the purely centralized control algorithm and distributed control algorithm in terms of message traffic for the network management. The result shows that the message traffic related to system performance is as low as centralized control algorithm and the system availability is independent of a specific processor failure.

• The Transactions of the Korea Information Processing Society
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• v.2 no.3
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• pp.277-287
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• 1995

For multipoint video conference of using multimedia communication terminals, terminals are logically connected each other, and there are centralized method and distributed method in connection between terminals. Multipoint control unit is needed for the centralized method, there are two methods for implementaion such as digital method and analog method. For a meaning and implementation method of multipoint control init, main funtions of multipoint control unit are summarized and the various implementation methods are proposed in this paper.