• Title, Summary, Keyword: 서지제어

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A Study on the Bibliographic Control of Printed Music (악보자료의 서지제어에 관한 연구)

  • Hahn, Kyung-Shin
    • Journal of Korean Library and Information Science Society
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    • v.40 no.1
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    • pp.275-296
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    • 2009
  • The purpose of this study is to investigate bibliographic control of printed music that is especially far-off the bibliographic control activities. In this study, therefore, the production and distribution channels of printed music and their publication situation are investigated. Then the development of bibliographic control of printed music is examined. And also, domestic, foreign, and international bibliographic control activities of printed music are analyzed. Finally, the special issues to be considered in our bibliographic control of printed music are presented.

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서지의 발생에서 방지까지⑤

  • 허광무
    • Electric Engineers Magazine
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    • v.235 no.3
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    • pp.21-26
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    • 2002
  • 서지를 제어하기 위해서는 3가지 정도를 고려해 볼 수 있다. 첫째는 서지를 흡수하는 것이다. 이 방식은 엄청난 양의 서지를 축적할 수 있는 방법은 아직 현재 과학으로 불가능하다. 둘째는 서지를 해소 시키는 것이다. 그러나 극히 짧은 순간에 높고 강한 서지를 열이 나 빛으로 변환하는 것도 어렵거니와 그로 인한 주변의 피해 또는 서지를 그냥 두었을때에 비하여 적다고 할 수 없을 것이다.

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A Study for RDA Implementation Scenarios and Future Bibliographic Control (RDA 구현 시나리오와 서지 제어의 장래에 대한 고찰)

  • Cho, Jane
    • Journal of the Korean Society for Library and Information Science
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    • v.43 no.3
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    • pp.85-105
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    • 2009
  • Disagreements between the technical environment and the conventional library catalog have caused a re-clarification of International Cataloguing Principles (ICP). Review is under way to finalize the publication of RDA (Resource Description and Access) in late 2009 by the Joint Steering Committee for Development of RDA. The impending RDA is based on FRBR (Functional Requirements for Bibliographic Records) which re-explains the bibliographic universe focused on entities, attributes and relationships between resources, but tries to maintain MARC as an encoding format for RDA. In this study, firstly FRBR, ICP and RDA were analyzed. Secondly, we propose 3 scenarios of RDA implementation: the future cataloging system based on the FRBR Entity, using a semantic web structure, and the scenario using the existing MARC format with some small changes. Finally, by examining response patterns of overseas bibliographic institutions, we present a set of urgent issues for future directions of bibliographic contro in Korea which includes, but not limited to, relationship between RDA/FRBR and KCR (Korean Cataloging Rules), continuation of KORMARC and authority control.

Countermeasure on the Suppression of Micro Surge and Noise for a Induction Motor Driven by Commercial Inverter (상용인버터 구동 유도전동기의 마이크로 서지 및 노이즈 억제에 관한 대책)

  • Kim, Duk-Hyun;Choi, Jeong-Won
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.22 no.10
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    • pp.111-117
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    • 2008
  • Generally, speed control for Induction motor widely used in industrial field is accomplished by commercial inverter. Induction motor driven by commercial inverter causes the micro surge voltage because of high speed switching of inverter. Micro surge brings about not only the breakdown of motor but also noise in PLC control system. And they court the enormous interference in activity for production. In this paper, we suggest the suppressible countermeasure for the breakdown of motor after the consideration of productive mechanism about micro surge. Experiment is performed by inverter with LCR filler in its output terminal. As a result, we confirmed that micro surge voltage is reduced. And the suppressible countermeasure for the noise of PLC control system is suggested by theoretical consideration.

Experimental Study of Compressor Surge for 250-hp Class Vehicular Turbocharger (250마력 급 차량용 터보차저 서지현상에 대한 실험적 연구)

  • Lee, Hyungchang;Han, Jaeyoung;Lee, Myeonghee;Im, Seokyoen;Yu, Sangseok
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.39 no.1
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    • pp.89-95
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    • 2015
  • A surge phenomenon cause noise and pulsations in a turbo compressor, which is an unstable operating regime. Because surge protection ensures a safe compressor operation, it is important to understand the physics of the surge phenomenon. In this study, the surge characteristics of a 250-hp class turbo-compressor were evaluated experimentally. The experimental parameters were the rotational speed, opening angles of the inlet guide vane and exit valve, and inlet pipe diameter and flow rates of the inlet gases. The results showed that the compressor surge was very sensitive to the gas flow rates, exit pressure, rotational speed, and bypass flow rates.

A Study on the Bibliographic Utility and Its Use of CIP Data : With a Focus on the LC CIP Program and OCLC (서지 유틸리티와 CIP 데이터 활용에 관한 연구 - OCLC와 미국국회도서관 CIP 프로그램을 중심으로 -)

  • Yoon Cheong-Ok
    • Journal of Korean Library and Information Science Society
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    • v.36 no.2
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    • pp.349-367
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    • 2005
  • This study examines how CIP program of the Library of Congress distributes, provides an access to, and helps upgrade CIP data through bibliographic utilities. LC CIP program can be characterized by the participation of many U.S. mainstream publishers, a continuing increase in the number of CIP data assigned annually, and an effort to immediately upgrade the completeness and accuracy of CIP data in cooperation with bibliographic utilities. Cooperation between LC and bibliographic utilities in performing quality control is worth noting, when compared with the limitation of CIP program of the National Library of Korea. It is suggested that the National Library of Korea should provide complete and accurate bibliographic and authority records for other types of new and old library materials published in Korea as well as CIP data for new monographic materials.

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Surge and Rotating Speed Control for Unmanned Aircraft Turbo-jet Engine (무인 항공기 터보 제트 엔진의 서지와 회전 속도 제어)

  • Jie, Min-Seok;Hong, Gyo-Young;Lee, Kang-Woong
    • Journal of Advanced Navigation Technology
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    • v.10 no.4
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    • pp.319-326
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    • 2006
  • In this paper, a fuzzy inference control system is proposed for a turbojet engine with fuel flow control input only. The proposed control system provides a practical fuel flow control method to prevent surge or flame out during engine acceleration or deceleration. A fuzzy logic is designed to obtain the fast acceleration and deceleration of the engine under the condition that the operating point should stay between the surge line and flame out control line. With using both engine rotating speed error and surge margin as fuzzy input variables, the desired engine rotating speed can be achieved to rapidly follow the engine control line without engine stall. Computer simulation using the MATLAB is realized to prove the proposed control performance to the turbojet engine which is linear modelized using DYGABCD program package.

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Surge Control of Small Turbojet Engines with Fuzzy Inference Method (소형 터보제트 엔진의 서지 제어를 위한 퍼지추론 기법)

  • Jie, Min-Seok;Hong, Seung-Beom
    • Journal of the Korean Society for Aviation and Aeronautics
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    • v.17 no.4
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    • pp.1-7
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    • 2009
  • The surge control system in unmanned turbojet engine must be capable of accounting uncertainties from engine transient conditions, random fluctuations of key parameters such as air pressure and fuel flow and engine modeling errors. In this paper, taking into consideration of its effectiveness as well as system stability, a fuzzy PI controller is proposed. The role of the fuzzy PI controller is to stabilize the unmanned aircraft upon occurring unexpected engine surge. The proposed control scheme is proved by computer simulation using a linear engine model. The simulation results on the state space model of a small turbojet engine illustrate the proposed control system achieves the desired performance.

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Surge Control of Turbofan Engine Compressor with the Variable Inlet Guide Vane (가변 안내익을 이용한 터보팬 엔진 압축기의 서지 제어)

  • Bae, Kyoungwook;Kim, Sangjo;Han, Dongin;Min, Chanoh;Lee, Daewoo
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.41 no.7
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    • pp.539-546
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    • 2013
  • Surge phenomenon can be occurred in a compressor when compressor performance of turbofan engine for an aircraft is changed considerably in a short time on the cases like take-off phase and changing of RPM from idle to maximum, because performance of aircraft engine is changed suddenly. This study is aimed to avoid surge in a compressor. Dynamic simulation in a compressor is modeled by simulink in specific condition. Fuel flow is control input, rpm and air mass flow are expressed in terms of transfer function. Surge margin is obtained by using compressor performance map from NPSS. VIGV(Variable Inlet Guide Vane) is controlled by PD controller with difference between surge margin and reference. Finally this paper verifies IGV can prevent surge phenomenon in a compressor.