• Journal of Environmental Impact Assessment
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• v.6 no.2
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• pp.81-92
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• 1997

This paper presents the results from the comparison analysis and evaluation between the air pollutant dispersion modeling results and the observation data in the area within a 10 km radius from the Boryong thermal power plants. The observation data used in this study were the air pollutant concentrations which had been continuously measured from 8 locations around the Boryong power plants by TMS(tele-monitoring system) for 3 months from September to November, 1996. The short-term and long-term predictions were carried out using ISC3 model and LPDM(Lagrangian Panicle Dispersion Model). The results of ISC3 modeling in a short-term showed highly as 0.7 in a correlation coefficient, but in a long-term showed just 0.54. On the other hand, LPDM showed 0.78 in a correlation coefficient for a long-term, but in a short-term showed highly value than the observation concentrations.

• Journal of international Conference on Electrical Machines and Systems
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• v.1 no.4
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• pp.517-524
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• 2012

The operation of linear oscillating system is complicated, involving system nonlinearities of both actuator and load, and variations of driving frequency in order to track the mechanical resonance. In this paper, both analytical and state-variable modeling techniques are used to investigate the influence of actuator parameters, such as back-emf/thrust force coefficient and cogging force, on the performance of linear oscillating systems. Analytical derivations are validated by simulations, and good agreements are achieved. The findings of the paper can greatly facilitate the design and evaluation processes of permanent magnet linear actuators.

• Journal of Magnetics
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• v.15 no.2
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• pp.85-90
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• 2010

This paper deals with the efficiency evaluations in a synchronous reluctance motor (SynRM) versus a permanent magnet assisted SynRM (PMASynRM), using a coupled transient finite element method (FEM) and Preisach modeling, which is presented to analyze the characteristics under the effects of saturation and hysteresis loss. We herein focus on the efficiency evaluation relative to hysteresis loss and copper loss on the basis of load conditions in a SynRM and PMASynRM. Computer simulation and experimental results for the efficiency, using a dynamometer, show the propriety of the proposed method and the high performance of the PMASynRM.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.53 no.2
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• pp.111-120
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• 2004

This paper presents an application of Unified Modeling Language(UML) software technique for developing transmission pricing evaluation package. Also, this paper describes a transmission pricing algorithm applicable to a large-scale power system. The usage-based transmission pricing mechanism is very complex since it requires power flow analysis, fault current analysis, sensitivity evaluation of a transmission line, penalty factors calculation, transmission asset databases, and cost allocation rules, etc. For the efficient and flexible development of the transmission pricing package, a UML. approach is applied, which is composed of a use-case diagram, interaction diagram, class diagram, and package diagram using Rational Rose Unified Process(RUP). The designed transmission pricing package can be efficiently modified and reused as the market environments evolves since it is designed by Object-Oriented Programming(OOP).

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.04a
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• pp.689-693
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• 1996

This paper was performed on the automatic selection of cutting condition on multispindle machine. the several mathematical relationships were formulated for simulataneous selection of machining parameters and tool changing scheme. In this research we used two step generative approach; step 1 is mathematical modeling for the selection of optimal cutting conditions and the other is GMDH-TYPE modeling to find prediction equation of system performance. thus in this paper, mathematical machining models combined with a heuristic GMDH-TYPE modeling to estimate the system performance, these models are developed computer programs for practical application and it was shown that the proposed approach has a good potential and offers a valuable tools to performance evaluation for metal cutting system.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.33A no.6
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• pp.206-219
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• 1996

This paper describes a data structure and evaluation algorithm to improve the perofmrances MOS logic-with-timing simulation in computation and accuracy. In order to efficiently simulate the logic and timing of driver-load networks, (1) a tree data structure to represent the mutual interconnection topology of switches and nodes in the driver-lod network, and (2) an algebraic modeling to efficiently deal with the new represetnation, (3) an evaluation algorithm to compute the linear resistive and capacitive behavior with the new modeling of driver-load networks are developed. The higher modeling presented here supports the structural and functional compatibility with the linear switch-level to simulate the logic-with-timing of digital MOS circuits at a mixed-level. This research attempts to integrate the new approach into the existing simulator RSIM, which yield a mixed-klevel logic-with-timing simulator MIXIM. The experimental results show that (1) MIXIM is a far superior to RSIM in computation speed and timing accuracy; and notably (2) th etiming simulation for driver-load netowrks produces the accuracy ranged within 17% with respect ot the analog simulator SPICE.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.4 no.4
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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.

• Proceedings of the Korean Nuclear Society Conference
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• 1997.10a
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• pp.663-668
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• 1997

한국형 차세대 원자로(KNGR)는 안전주입계통에 Advanced Design features를 채택하고 있는데, 그 중의 하나가 안전주입의 주입구를 Downcomer Annulus의 상부에 위치시킨 Direct Vessel Injection(DVI)으로서 영광 및 울진 3&4호기의 Cold Leg Injection(CLI)과는 다른 설계 개념이다. 본 논문에서는 DVI가 채택된 KNGR에 대하여 기존의 C-E형 발전소 해석에 적용한 C-E Evaluation Model(EM)을 사용하여 대형파단 냉각재상실사고를 해석해 보고자 하였다. 먼저 DVI의 Modeling은 KNOGR의 참조 발전소라 할 수 있는 System80+에서 Modeling한 것과 같이 CLI 해석에 사용한 Nodalization Scheme 중 Cold Leg Node에 연결된 SIT 만을 Downcomer Annulus Node에 연결하는 방법을 사용하여 DVI 해석을 수행하였다. 아울러 기존의 안전주입 형태인 CLI에 대한 해석을 KNGR에 대해 병행하여 수행함으로써 DVI와 CLI의 ECCS performance를 비교하고 CLI 대비 DVI의 특성을 알아보았다. 또한 DVI의 해석에 있어서 SIT와 Cold Leg이 함께 연결되는 Downcomer Annulus Node를 상하 2개로 분리하여 SIT와 Cold Leg 각각에 연결시킴으로써 DVI 주입구의 위치에 대한 보다 정확한 Modeling을 시도하였다. 그 결과 DVI 주입구의 높이를 고려한 경우가 DVI의 일반적 물리 현상에 근접하게 계산되는 것으로 판단되나 현재로서는 특별한 검증 수단이 없으므로 향후 Licensing 해석 수행에 앞서 방법론을 포함한 이에 대한 보다 심도 있는 검토가 필요할 것으로 판단된다.

• Proceedings of the KIPE Conference
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• 2005.07a
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• pp.520-522
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• 2005

Islanding phenomenon is undesirable because it lead to a safety hazard to utility service personnel and may cause damage to power generation and power supply facilities as a result of unsynchronized reclosure. In order to prevent this phenomenon, various anti-islanding methods have been studied. Even though the slip mode frequency shift (SMS) method has been regarded as a highly effective anti-islanding method, the analytical design method of that was not cleared. This paper proposes a modeling of the SMS method using non-detection zone (NDZ) and evaluation of the method according to the test conditions of IEEE Std. 929-2000. The SMS method is derived analytically through the modeling and verified visually by simulation and experiment.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2005.11a
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• pp.345-348
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• 2005

In this paper, we suggested an evaluation model for satisfaction of e-Learning. This model was composed decision of evaluation criteria, analysis of consciousness structure for evaluation factors using the Fuzzy Structural Modeling method, decision of weights for evaluation factors considering intersectional dependence relations and evaluation of satisfaction of e-Learning. The case study of this model was done for comparative analysis between teachers and students of e-Learning in high school.