• Journal of Communications and Networks
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• v.5 no.3
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• pp.197-201
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• 2003

We study in this paper both distributed power control and removal algorithms for multimedia CDMA wireless networks. In our study, users can have different data rates as well as different quality of service (QoS) requirements. We derive a necessary and sufficient condition for the fully distributed power control (FDPC) algorithm to find a feasible power set. We also prove that, if the maximal power level is used at the start, then the distributed constrained power control (DCPC) algorithm is equivalent to the FDPC algorithm. For the connection removal algorithm, we prove that the non-reinitialized removal algorithm finds a feasible power set faster and employs smaller power levels than the reinitialized one does. Performances of some connection removal criteria are also studied. Our simulation results reveal that the smallest normalized CIR (SNC) and largest CIR requirement (LCR) criteria result in smaller outage probability than the smallest CIR (SC) criterion in a multimedia environment.

• The Transactions of the Korean Institute of Power Electronics
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• v.23 no.5
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• pp.345-351
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• 2018

A distributed control method is proposed to improve the power sharing performance of bidirectional distributed generators and the voltage regulation performance of a DC bus in a DC microgrid. Voltage sensitivity analysis based on power flow analysis is conducted to analyze the structural characteristics of a DC microgrid. A distributed control method using a voltage sensitivity matrix is proposed on the basis of this analysis. The proposed method uses information received through the communication system and performs the droop gain variation method and voltage shift method without additional PI controllers. This approach achieves improved power sharing and voltage regulation performance without output transient states. The proposed method is implemented through a laboratory-scaled experimental system consisting of two bidirectional distributed generators, namely, a load and a non-dispatchable distributed generator in a four-bus ring-type model. The experimental results show improved power sharing accuracy and voltage regulation performance.

• Journal of Korean Institute of Industrial Engineers
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• v.38 no.1
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• pp.31-40
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• 2012

Distributed arrival time control (DATC) is a distributed feedback control algorithm for real-time scheduling problems in dynamic operational environment. Even though DATC has provided excellent performance for dynamic scheduling problems, it can be improved by considering the following considerations. First, the original DATC heavily depends on the quality of initial solution. In this paper, well-known dispatching rules are incorporated DATC algorithm to enhance its performance. Second, DATC improves its solution with adjusting virtual arrival times of jobs to be scheduled in proportion to the gap between completion time and due date iteratively. Since this approach assigns the same weight to all gaps generated with iterations, it fails to utilize significantly more the latest information (gap) than the previous ones. To overcome this issue we consider exponential smoothing which enable to assign different weight to different gaps. Using these two consideration This paper proposes A-DATC (Advanced-DATC). We demonstrate the effectiveness of the proposed scheduling algorithm through computational results.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.62 no.3
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• pp.117-126
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• 2013

This paper is written for the development and application of boiler furnace pressure control algorithm and distributed control system of coal-fired power plant by the steps of design, coding, simulation test, site installation and site commissioning test. The control algorithms were designed in the shape of cascade control for two parts of furnace pressure control and induced draft fan pitch blade by standard function blocks. This control algorithms were coded to the control programs of distributed control systems. The simulator for coal-fired power plant was used in the test step and automatic control, sequence control and emergency stop tests were performed successfully like the tests of the actual power plant. The reliability was obtained enough to be installed at the actual power plant and all of distributed control systems had been installed at power plant and all signals were connected mutually. Tests for reliability and safety of plant operation were completed successfully and power plant is being operated commercially. It is expected that the project result will contribute to the safe operation of domestic new and retrofit power plants, the self-reliance of coal-fired power plant control technique and overseas business for power plant.

• Journal of the Korea Computer Industry Society
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• v.2 no.8
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• pp.1099-1108
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• 2001

In this paper, we proposed an efficient method of management in which various design objects in the environments for distributed software development. Those design objects are created in the environments for distributed software development based on Unified Modeling Language as well as versions of source codes. In this research, a version control technique has been specially focused that is based on our proposed version rules to consistently control versions from web-based distributed software development which enables developers to independently manage distributed objects from the software development platform. Based on the version control technique, we have designed a web-based rule-control version management model that has been proposed here.

• Proceedings of the KIEE Conference
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• 2002.07d
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• pp.2531-2533
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• 2002

In this paper, we evaluate feasibility of an object-oriented method in a distributed real-time control environment through the prediction of delay expected. We adopt CAN as the distributed network and the application layer of the CAN is composed of client/server communication model of COM and surroundings for the support of real-time capability of the COM. Mathematical models formalizing delays which are predicted to invoke in the COM architecture are proposed. Sensors and actuators which are widely used in distributed network-based systems are represented by COM objects in this paper. It is expected that the mathematical models can be used to protect distributed network-based systems from violation of real-time features by the COM.

• Journal of Institute of Control, Robotics and Systems
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• v.8 no.5
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• pp.434-437
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• 2002

A small size and light-weight DSP board is newly designed for a real time multi-distributed control system that overcomes constraints on time and space. There are a variety of protocols for a real-time distributed control system. In this research, we selected CAN for the multi distributed control, which was developed by the BOSCH in the early 1980's. If CAN and Internet are connected together, the system attains the characteristics of a distributed control system and a remote control system simultaneously. To build such a system. The TCP/IP-CAN Gateway which converts a CAN protocol to TCP/IP protocol and vice verse, was designed. Moreover, the system is required to be small and light-weighted for the high mobility and cost effectiveness. The equipment in remote place has a TCP/IP-CAN Gateway on itself to be able to communicate with another systems. The received commands in the remote site are converted from TCP/IP protocol to CAN protocol by the TCP/IP-CAN Gateway in real time. A simulation system consists of a TCP/IP-CAN Gateway in remote place and a command PC to be connected to Ethernet.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.23 no.6 s.165
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• pp.922-930
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• 1999

This paper describes a new 14-CPU real-time distributed automatic gauge control (AGC) system for POSCO's No. 2 Hot Strip Mill at Pohang Works. The new AGC system has adopted gaugemeter AGC, Monitor AGC, and roll gap disturbance compensators. The computer system for the new AGC system has been developed based on VMEbus computer systems and a commercial real-time operating system. A VMEbus computer system is also used for the position servo control of hydraulic cylinders. All the application programs and input/output signals have been reasonably distributed over the control computer systems for the maximum reliability and effectiveness of the system. The new AGC system has been successfully used for the No. 2 Hot Strip Mill.

• Journal of Institute of Control, Robotics and Systems
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• v.20 no.11
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• pp.1131-1135
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• 2014

This paper proposes the enhanced faulty node detection scheme with hybrid algorithm using Markov-chain model on BCH (Bose-Chaudhuri-Hocquenghem) code in naval distributed control networked systems. The probabilistic model-driven approach, on Markov-chain model, in this paper uses the faulty weighting interval factors, which are based on the BCH code. In this scheme, the master node examines each slave-nodes continuously using three defined states : Good, Warning, Bad-state. These states change using the probabilistic calculation method. This method can improve the performance of detecting the faulty state node more efficiently. Simulation results show that the proposed method can improve the accuracy in faulty node detection scheme for real-time naval distributed control networked systems.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.39 no.10
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• pp.1075-1085
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• 1990

This paper presents a new method for the optimal control of the distributed parameter systems by a decentralized computational procedure. Approximate lumped parameter models are derived by using the Galerkin method employing the Legendre polynomials as the basis functions. The distributed parameter systems, however, are transformed into the large scale lumped parameter models. And thus, the decentralized control scheme is introduced to determine the optimal control inputs for the obtained lumped parameter models. In addition, an approach to block pulse functions is applied to solve the optimal control problems of the obtained lumped parameter models. The proposed method is simple and efficient in computation for the optimal control of distributed paramter systems. Illustrative examples given to demonstrate the validity of the presently proposed method.