• Title/Summary/Keyword: Operational flexibility

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An Efficient Method for Controlling the Number of Proofs in Prolog (프롤로그에서 증명의 수를 효과적으로 제어하기 위한 방법)

  • Nam, Young-Kwang
    • The Transactions of the Korea Information Processing Society
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    • v.4 no.6
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    • pp.1557-1564
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    • 1997
  • We propose an extension to Prolog called the count term for controlling Prolog execution. The purpose is to allow the programmers as well as the users to have greater flexibility in controlling the execution behavior of Prolog programs and for limiting the number of answers or proofs retrieved when Prolog is used as a database query language. Both syntax and operational semantics of the count term are defined. An implementation strategy based on WAM (Warren Abstract Machine) by modifying instructions related to backtracking behavior has been suggested.

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Modeling and Intelligent Scheduling for FMC (FMC의 모델링과 지능형 스케쥴링)

  • 서기성;이노성;안인석;우승규;이규호;우광방
    • Journal of the Korean Institute of Telematics and Electronics B
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    • v.30B no.3
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    • pp.31-40
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    • 1993
  • This paper deals with the modeling and scheduling for FMC(Flexible Manufacturing Cells). The FMC system composed of unit or multi cells is capable of improving productivity with flexibility for machine. However, the properties of multiple jobs and various alternatives results in tne dynamic states which make system management very complex. The extended Peti nets are used to represent for complex properties of FMC which performs short-term scheduling and dynamic operational scheduling. The hierarchical control structure and integlligent scheduling through expert module are adopted for efficiency of FMC operations. The computer simulation reveals that intelligent scheduling method is better than heuristics in various performance indices.

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An Application of a PLC to a control System for a Single Tower Drier In Nuclear Power Plant (PLC를 이용한 Single Tower Drier 운전 적용에 관한 연구)

  • Park, Jong-Beom;Yang, Seung-Kwon;Park, Ik-Soo
    • Proceedings of the KIEE Conference
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    • 1997.11a
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    • pp.567-569
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    • 1997
  • A control system using a PLC has been developed for a single tower drier(STD) in a CANDU type nuclear power plant. This system will replace the existing STD control system which was implemented with mechanical timers and relays. The new control system makes it possible for an operator to perform more precise time and dew point control for the STD, thanks to the high efficiency and flexibility of the PLC. The operational cost for the control system is much reduced compared to the existing system.

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Single and Two-Phase Flow Pressure Drop for CANFLEX Bundle

  • Park, Joo-Hwan;Jun, Ji-Sun;Suk, Ho-Chun;Dimmick, G.R.;Bullock, D.E.
    • Proceedings of the Korean Nuclear Society Conference
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    • 1998.05a
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    • pp.532-537
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    • 1998
  • Friction factor and two-phase flow frictional multiplier for a CANFLEX bundle are newly developed and presented in this paper. CANFLEX as a 43-element fuel bundle has been developed jointly by AECL/KAERI to provide greater operational flexibility for CANDU reactor operators and designers. Friction factor and two-phase flow frictional multiplier have been developed by using the experimental data of pressure drops obtained from two series of Freon-l34a (R-134a) CHF tests with a string of simulated CANFLEX bundles in a single phase and a two-phase flow conditions. The friction factor for a CANFLRX bundle is found to be about 20 % higher than that of Blasius for a smooth circular pipe. The pressure drop predicted by using the new correlations of friction factor and two-phase frictional multiplier are well agreed with the experimental pressure drop data of CANFLEX bundle within ${\pm}\;5\;%$ error.

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Cooling Characteristics of a Strip Fin Heat Sink (스트립휜 히트싱크의 냉각특성)

  • Park. Cheol-Woo;Kim. Hyun-Woo;Jang .Chung-Sun;Riu. Kap-Jong
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.29 no.1 s.232
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    • pp.16-26
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    • 2005
  • Air-cooled heat sinks are employed in many electronic cooling applications since they provide significant heat transfer enhancement and operational flexibility. Strip-shaped fin heat sink is of interest and needs to be investigated as general cooling products for more applicability. The purposes of this study are to evaluate heat sink performance without bypass flow condition and to determine optimal heat sink geometries. The results show that the decreasing rate of thermal resistance of a heat sink decreases with increasing inlet air velocity, and the increasing rate of pressure drop increases with increasing inlet air velocity, but is not affected by input power. The increasing rate of optimal longitudinal fin spacing is larger than that of transverse fin spacing. The strip fin heat sink tested in this study showed better cooling performance compared to that of other plate fin type.matism. 2004; 50(11): 3504-3515.

Experimental Operation Analysis of Unified Power Flow Controller with Cascaded H-Bridge Modules (다계 H-브리지 모듈로 구성된 UPFC(Unified Power Flow Compensator)의 실험적 동작분석)

  • Baek, Seung-Taek;Bae, Byung-Yeol;han, Byung-Moon;Baek, Doo-Hyun;Jang, Byung-Hoon;Yoon, Jong-Soo;Kim, Soo-Yeol
    • Proceedings of the KIPE Conference
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    • 2005.07a
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    • pp.389-391
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    • 2005
  • This paper describes experimental analysis of UPFC, which is composed of cascaded H-bridge modules and single-phase multi-winding transformers for isolation. The operational characteristic was analyzed through experimental works with a scaled model, and simulation results with PSCAD/EMTDC. The UPFC proposed In this paper can be directly connected to the transmission line without series injection transformers. It has flexibility to expand the operation voltage by increasing the number of H-bridge modules. The analysis results can be utilized to design the actual UPFC system applicable for the transmission system.

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An Application of a PLC to a control System for a Dual Tower Drier in Nuclear Power Plant (PLC를 이용한 Dual Tower Drier 운전 적용에 관한 연구)

  • Park, Jong-Beom;Park, Ik-Soo;Cho, Whang
    • Proceedings of the KIEE Conference
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    • 1998.07g
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    • pp.2321-2323
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    • 1998
  • A control system using a PLC has been developed for a dual tower drier(DTD) in a CANDU type nuclear power plant. This system will replace the existing DTD control system which was implemented with mechanical timers and relays. The new control system makes it possible for an operator to perform more precise time and dew point control for the DTD, thanks to the high efficiency and flexibility of the PLC. The operational cost for the control system is much reduced compared to the existing system.

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Experimental Analysis Result of Unified Power Quality Controller with Cascaded H-Bridges using Scaled Prototype (H-브리지로 구성된 UPQC(Unified Power Quality Conditioner)의 축소모형 실험결과 분석)

  • Cho, Yun-Ho;Han, Syung-Moon;Kim, Hyun-Woo
    • Proceedings of the KIEE Conference
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    • 2005.10a
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    • pp.93-96
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    • 2005
  • This paper describes experimental analysis of UPQC, which is composed of cascaded H-bridges and single-phase multi-winding transformers. The operational characteristic was analyzed through experimental works with a scaled model, and simulations with PSCAD/EMTDC. The UPQC proposed in this paper can be directly connected to the distribution line without series injection transformers. It has flexibility to expand the operation voltage by increasing the number of H-bridge modules. The analysis results can be utilized to design the actual UPQC system applicable for the actual distribution system.

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Experimental Operation Analysis of Unified Power Flow Controller with Cascaded H-Bridge Modules (다계 H-브리지 모듈로 구성된 UPFC(Unified Power flow Compensator)의 실험적 동작분석)

  • Baek Seung-Tak;Han Byung-Moon;Choo Jin-Boo;Chang Byung-Hoon;Yoon Jong-Su
    • The Transactions of the Korean Institute of Electrical Engineers B
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    • v.54 no.9
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    • pp.422-430
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    • 2005
  • This paper describes experimental analysis of UPFC, which is composed of cascaded H-bridge modules and single-phase multi-winding transformers for isolation. The operational characteristic was analyzed through experimental works with a scaled model, and simulation results with PSCAD/EMTDC. The UPFC proposed in this paper can be directly connected to the transmission line without series injection transformers. It has flexibility to expand the operation voltage by increasing the number of H-bridge modules. The analysis results can be utilized to design the actual WFC system applicable for the transmission system.

Dynamic Performance Analysis of Unified Power Quality Conditioner with Cascaded H-Bridges (다중브리지로 구성된 UPQC(Unified Power Quality Conditioner)의 동적 성능분석)

  • Han, Byung-Moon;Soh, Yong-Cheol;Kim, Hyun-Woo
    • The Transactions of the Korean Institute of Electrical Engineers P
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    • v.55 no.2
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    • pp.94-102
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    • 2006
  • This paper describes experimental analysis of UPQC, which is composed of cascaded H-bridges and single-phase multi-winding transformers. The operational characteristic was analyzed through experimental works with a scaled model, and simulations with PSCAD/EMTDC. The UPQC proposed in this paper can be directly connected to the distribution line without series injection transformers. It has flexibility to expand the operation voltage by increasing the number of H-bridge modules. The analysis results can be utilized to design the actual UPQC system applicable for the actual distribution system.