• Proceedings of the KIEE Conference
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• 1993.07a
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• pp.501-503
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• 1993

A circuit of sigmoid function for neural network is designed by using Piecewise Linear (PWL) method. The slope of sigmoid function can be adjusted to 2 and 0.25. Also the circuit presents both sigmoid function and its differential form. The circuits is simulated by using ViewLogic. Theoretical and simulated performance agree with 1.8 percent.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.2
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• pp.280-286
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• 2009

The NGN(Next-Generation Network) structure has been considered from various points of view as all If wireless-wired integration network and its performance is one of the main issue in these days. In this paper, various wired and wireless integrated networks with voice service are designed and simulated to obtain problems and factors affects the network performance using OPnet simulator. The characteristics only showed in the wired and wireless integrated networks are measured and analyzed compared with the single networks such as a wired or wireless networks. Especially, in the wired and wireless integrated networks showed degrading performance even if there are few transmissions in the network and furthermore, the various networks of increasing numbers of the nodes and transmission are simulated and evaluated.

• Proceedings of the Acoustical Society of Korea Conference
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• 1994.06c
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• pp.407-410
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• 1994

In this paper, we describe the new unsuperivised learning algorithm, SASOM. It can solve the defects of the conventional SOM that the state of network can't converge to the minimum point. The proposed algorithm uses the object function which can evaluate the state of network in learning and adjusts the learning rate flexibly according to the evaluation of the object function. We implement the simulated annealing which is applied to the conventional network using the object function and the learning rate. Finally, the proposed algorithm can make the state of network converged to the global minimum. Using the two-dimensional input vectors with uniform distribution, we graphically compared the ordering ability of SOM with that of SASOM. We carried out the recognitioin on the new algorithm for all Korean phonemes and some continuous speech.

• Journal of Power Electronics
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• v.8 no.1
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• pp.23-34
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• 2008

This paper deals with a Direct Torque Control (DTC) of an Interior Permanent Magnet Synchronous Motor (IPMSM) for the Electric Vehicle (EV) propulsion system using a Neural Network (NN). The Conventional DTC with optimized switching lookup table and three level torque controller generates relatively large torque ripples in an electric vehicle motor drive. For reducing the torque ripples, a three level torque controller is hereby replaced by the five level torque controller. Furthermore, the switching lookup table of the five level torque controller based DTC is replaced with a Neural Network. These DTC schemes of an IPMSM drive are simulated using MATLAB/SIMULINK. The simulated results are compared with the conventional DTC and it is found that the ripples in the torque, as well as in the stator current, are reduced drastically.

• Transactions of the Korean Society of Mechanical Engineers
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• v.17 no.12
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• pp.3063-3072
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• 1993

The layout is an important and difficult problem in industrial applications like sheet metal manufacturing, garment making, circuit layout, plant layout, and land development. The module layout problem is known to be non-deterministic polynomial time complete(NP-complete). To efficiently find an optimal layout from a large number of candidate layout configuration a heuristic algorithm could be used. In recent years, a number of researchers have investigated the combinatorial optimization problems by using neural network principles such as traveling salesman problem, placement and routing in circuit design. This paper describes the application of Self-organizing Feature Maps(SOM) of the Kohonen network and Simulated Annealing Algorithm(SAA) to the layout problem of the two-dimensional rectangular shapes.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.431-432
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• 2007

It is necessary for the stabilized operation of the power system even if a severe condition in system operation takes place. There is the need to develop the intelligent Power grid Monitoring System. In this system, the PMU(Phasor Measurement Unit) measures the synchrophasor and transmits it to the PIDS(Power Infrastructure Defense System). The IEEE PC37.118 protocol defines the message format to implement the communication both the PMU and the PIDS. In this paper, We measure and analyze the network traffic from simulated the PMU to simulated the PIDS according to network routing. And, We present the finest network routing in developing the intelligent Power grid Monitoring System.

• Proceedings of the KIEE Conference
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• 2003.07d
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• pp.2121-2123
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• 2003

Distributed Control Systems(DCS) arc used in a wide range of process applications such as power plants. This paper presents calculated network capacity of a DCS that developed for nuclear power plant. The network hierarchies are 3 layed of information network, control network and field network. The assumed total node number of maximum DCS network is 64. Worst case network utilization of the DCS is simulated and analyzed.

• Journal of Industrial Technology
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• v.28 no.B
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• pp.9-14
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• 2008

In the Reporting Cell Location Management (RCLM) system, a subset of cells in the network is designated as the reporting cells. Each mobile terminal performs location update only when it enters one of these reporting cells. When a call arrives, the paging is confined to the reporting cell the user last reported and the neighboring bounded non-reporting cells. Frequent location update may result in degradation of quality of service due to interference. Miss on the location of a mobile terminal will necessitate a search operation on the network when a call comes in. We must decide the number of reporting cells and which cell should be reporting cell to balance the registration (location update) and search (paging) operations to minimize the cost of RCLM system. This paper proposes a simulated annealing (SA) for optimization of RCLM system.

• Journal of the Korea Institute of Military Science and Technology
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• v.14 no.4
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• pp.556-563
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• 2011

Recently, the development of military system is focused on Network Centric Warfare. But, there is no deployed Command and Control System for Missile System in the country. Therefore, Command and Control System for Missile System was simulated to predict feasibility for the future development in this paper. The contents of the design and implementation for simulated system are described in details. Besides, a method for avoiding collisions in 1:N radio communication environment is proposed as the future work. The simulated system in this paper will be a help to developing Command and Control System for Missile System in the future.

• Water for future
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• v.29 no.2
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• pp.153-165
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• 1996

One-dimensional unsteady flow model including weir flow simulation is studied. Applicabilities of both the single channel model with local treatment of the weir overflow, and the looped-network model are studied using a test problem. It is shown that various type of weir flows including reverse flows are successfully simulated. Flow discontinuity due to the high crest elevation can also be simulated. The reverse free-flowing overflow can be simulated by the single-channel model as well as by the looped-network model.