• Journal of the Korean Society for Precision Engineering
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• v.10 no.1
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• pp.100-107
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• 1993

In this study, it is analyzed that an electromagnet whose generating force is proportional to constant current through coil in its coperating range. To find arelation between magnetic force and the structure in electromagnet, computer simulation method is used by permeance modeling method. When the electromagnet is applied to flow control valve, the relation between input current and flow is found. In order to get a reliability of computer simluation, the simulation results are compared to the experimental result. As the simulation is processed repeatedlyl. it is found that the gap size between plunger and guide steel and the length of tapered brass ring are important factors in electromaget.

• Proceedings of the KSR Conference
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• 2007.11a
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• pp.982-988
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• 2007

The input data for the interior material of the train is one of the key points for enhancing the accuracy of fire simulation. In this study, we investigated the Fire Test Methods for the Fire Dynamic Simulator modeling for railroad passenger trains. We should get the thermal inputs such as ignition temperature, conductivity, specific heat, vaporization heat, effective heat release. With the simple conduction model for cone-calorimeter test, they could get more than HRR. Kinds of methodology were introduced for better thermal data for real material.

• Proceedings of the IEEK Conference
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• 2007.07a
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• pp.421-422
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• 2007

In underwater, acoustic waves are used for telecommunication. The communication channels are very complicated, because of the distribution of temperature in depth, reflections from boundaries like as the surface of water and the bottom. We report the constitution of the underwater acoustic channel using the simulation of the Transmission Line Matrix Modeling and cross-correlations from the input and output signals.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.3
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• pp.535-546
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• 2000

Juam lake is a major water resource for the industrial and agricultural activities as well as the resident life of Kwangju and Chonnam area. However, the water quality of the lake is getting worse due to a large quantity of pollutant inflowing to the lake. As a preliminary step in making the countermeasure to achieve the water quality goal of the lake. it is necessary to understand how the water quality of the lake will be in future. Several computer programs can be used to predict the water quality of lake. Each of these programs requires a number of input data such as hydrological and meteorological data. and the quantity of the pollutant inflowed. but some or most of the input data contain uncertainty. which eventually results in the uncertainty of prediction value (future level of water quality). Generally. the uncetainty stems from the lack of information available. the randomness of future situation. and the incomplete knowledge of expert. Thus. the purpose of this study is to present a method for representing the degree of the uncertainty contained in input data by applying fuzzy theory and incorporating it directly into the water quality modeling process. By using the method. the prediction on the future water quality level of Juam lake can be made that is more appropriate and realistic than the one made without taking uncertainty in account.

• Journal of the Korea Institute of Military Science and Technology
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• v.12 no.5
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• pp.590-600
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• 2009

In the simulation of underwater vehicles such as a submarine or a torpedo, various type of simulations like an engineering level simulation for predicting the performance precisely and an engagement level simulation for examining the effectiveness of a certain tactic is required. For this reason, a tactics manager which can change the behavior of a simulation model according to external tactics is needed. In this study the tactics manager supporting a script language and engine which can represent various tactics and can help users define external input tactics for the tactic manager easily is suggested. Python and Lua which are representative among script languages have been compared and analyzed from the viewpoint of a tactic manage, and the tactic manger using the script engines of those script languages was implemented. To demonstrate the effectiveness of the tactic manager, a target motion analysis simulation of the warfare between a submarine and a surface ship.

• Journal of Institute of Control, Robotics and Systems
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• v.10 no.3
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• pp.280-285
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• 2004

This paper is concerned with the modeling and identification of sequencing batch reactor (SBR) via genetic algorithm based polynomial neural network (GA-based PNN). The model describes a biological SBR used in the wastewater treatment process fur nitrogen removal. A conventional polynomial neural network (PNN) is applied to construct a predictive model of SBR process fur nitrogen removal before. But the performances of PNN depend strongly on the number of input variables available to the model, the number of input variables and type (order) of the polynomials to each node. They must be fixed by the designer in advance before the architecture is constructed. So the trial and error method must go with heavy computation burden and low efficiency. To alleviate these problems, we propose GA-based PNN. The order of the polynomial, the number of input variables, and the optimum input variables are encoded as a chromosome and fitness of each chromosome is computed. Simulation results have shown that the complex SBR process can be modeled reasonably well by the present scheme with a much simpler structure compared with the conventional PNN model.

• Proceedings of the Korea Society for Simulation Conference
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• 1997.04a
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• pp.23-28
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• 1997

We discuss development of a simulator for automated manufacturing systems (AMSs) which have sophisticated automated material handling equipments and complicated work flows. The simulator is designed to satisfy the following requirements. A user should be able to easily configure or specify an AMS through a graphical user interface (GUI) and minimal data input. The user should be able to model diverse and complied control logic for automated material handling systems like automated guided vehicle (AGV) systems, robot workcell systems and conveyor systems as well as complicated job flow program. Real time animation is desired. Finally, the simulator should be easily maintained and extended. To satisfy the requirements, we use an object-oriented paradigm for modeling, designing, and programming of the simulator. We use an object-oriented modeling framework to design the modeling elements library, and take the process interaction approach for scheduling processes and events. To model a user-defined diverse control logic, we also develop a script language and its interpreter. We explain design and implementation strategies. We implement the simulator using Visual C++ 4.2 and Open GL on Windows NT and the Windows95. Some modeling examples will be demonstrated.

• Proceedings of the KIPE Conference
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• 1997.07a
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• pp.393-399
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• 1997

Single-phase and three-phase AC to DC power converters are becoming frequently used for high voltage/high power applications such as telecommunications. They often require input/output transformer isolation for safety, a unity input power factor for minimum reactive power, free input harmonic currents fed back to the AC Power distribution system and, finally, high efficiency and high power density for minimum weight and volume. The proposed boost converter for power factor correction (PFC) provides an unity input power factor, low harmonic distortion and high efficiency along with reduced volume and weight. Single-phase 220VAC input/380VDC 1KW output prototype is constructed and experimental results will be verified with those of PSpice simulation.

• Proceedings of the KIEE Conference
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• 1999.07f
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• pp.2712-2714
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• 1999

The small signal model for input series-output parallel connected converter system employing charge control together with input capacitor voltage feedback loop is developed. From the model developed, the effect of input capacitor voltage feedback loop to the system stability and outer loop compensator design is analyzed. Theoretical results and simulation show that input capacitor voltage feedback loop has no critical effects on the system stability, so the system can be reduced to a equivalent single module for the stability analysis and outer loop compensator design.

• Journal of Advanced Navigation Technology
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• v.2 no.1
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• pp.34-42
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• 1998

An adaptive state and input estimator for the tracking of a target with unknown randomly switching input is developed. In modeling the unknown inputs, it is assumed that the input sequence is governed by semi-Markov process. By incorporating the semi-Markov probability concepts into the Bayesian estimation theory, an effective adaptive state and input estimator which consists of parallel Kalman-type filters is obtained. Computer simulation results reveal that the proposed adaptive estimator have improved tracking performance in spite of the unknown randomly switching input.