• 제목/요약/키워드: major issue

검색결과 1,523건 처리시간 0.033초

How strong magnetic fields can be in AGN accretion flows

  • Pariev, Vladimir
    • 한국우주과학회:학술대회논문집(한국우주과학회보)
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    • 한국우주과학회 2008년도 한국우주과학회보 제17권2호
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    • pp.22.2-22.2
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    • 2008
  • Radio and X-ray observations of radio lobes in galaxy clusters indicate large energies stored in the magnetic fields in the radio lobes. These magnetic fields are undoubtedly produced and amplified by the accretion onto the central supermassive black hole. I review recent progress and remaining problems in our understanding of the ways how these magnetic fields can be produced and amplified in the accretion disks and what can be the limiting strength of the magnetic field. The major remaining issue is how ordered magnetic spirals (or jets) can emerge from the turbulent small scale magnetic fields produced by MRI. Another issue is the ratio of the axial to the azimuthal magnetic field in jets.

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해상 및 항공물류보안의 법규 및 정책에 관한 연구 (A study on the rules and policy of the maritime and aviation supply chain security)

  • 최병권
    • 무역상무연구
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    • 제42권
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    • pp.247-274
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    • 2009
  • The supply chain security programs are designed to prevent terrorist attacks on world transit system, and to help protect the passengers and workers who use these systems on a daily basis. as evidenced by the train bombings in London and Madrid in recent years, the threats to America's transit systems are real. After 9 11 terrors in 2001, security problem is appearing to every nations and international organizations main pending issue than any problem and various countermeasure is prepared. Security is the major issue in international trade, with significant potential costs and economic impact. So, We need to ensure that supply chain security does not become a new non-tariffs barrier. The aim of this study is to examine the international maritime and aviation law on the supply chain security. Also I review the supply chain security in U.S. and other countries.

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QSS 해석 기법을 이용한 Voltage Security Assessment(VSA) 프로그램 기반설계 (Framework Design of Voltage Security Assessment(VSA) using QSS Analysis method)

  • 허진;이상호;김태현;문영환
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2005년도 제36회 하계학술대회 논문집 A
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    • pp.12-14
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    • 2005
  • Security problem has been a fundamental issue in the operation and planning of power system. Voltage instability is widely recognized as an important issue of power system blackout. As far as real-time operation is concerned, there is a need for appropriate tools to identify dangerous contingencies, assess security margins and suggest corrective actions. In this paper, we propose the framework design of Voltage Security Assessment(VSA) using QSS(Quasi Steady-State) analysis method in order to implement fast time domain simulation engine as a major part of VSA.

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최신PEEP제어 시스템 개발 (Advanced PEEP Controlled system development)

  • 김종철;이상학;주정규
    • 대한전자공학회:학술대회논문집
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    • 대한전자공학회 2008년도 하계종합학술대회
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    • pp.137-140
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    • 2008
  • The purpose of PEEP is to increased effect reparation in lung. Recently trend of technology is possible to have multi-level or to control freely for variety breathing pattern or breathing mode. Those new technology need some issue like electronic controlled actuator(solenoid), PEEP valve of special structure and control software in micro controller. This paper brief to develop actuator(solenoid) and PEEP valve. This development is to make commercial product of MEKICS.Co.LTD Electronic controlled actuator(Solenoid) is to make force depend on current in linear. And force is convert to pressure in PEEP valve. Major technical issue are how to make the valve with continuous force even dough moving and how to optimize to convert force - pressure.

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SIMULTANEOUS OPTIMIZATION OF TOLERANCE SYNTHESIS IN ASSEMBLY AND COMPONENT DIMENSIONS

  • Kim Young Jin;Cho Byung Rae
    • 한국경영과학회:학술대회논문집
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    • 한국경영과학회/대한산업공학회 2003년도 춘계공동학술대회
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    • pp.529-536
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    • 2003
  • The majority of previous studios on tolerance synthesis have viewed the issue as a design methodology to determine optimal component tolerances on behalf of a manufacturer. while meeting given assembly tolerance requirements Although a considerable amount of research has been done on this issue. a couple of important questions still remain unanswered First. how ran a design engineer quantitatively incorporate a customer's perception on a product quality into a tolerance synthesis scheme at the early design stage Second. how ran component tolerances and assembly tolerance be optimized in a simultaneous way? To answer these questions. this article presents the customer-driven concurrent tolerance synthesis which is facilitated by the notion of truncated distribution and the use of mathematical programming techniques. while adopting the major principles of Tagurhl philosophy. The work presented in the article is an effort to gain insight, which can be useful in practice when setting up guidelines for an overall tolerance synthesis.

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기후변화에 따른 해양생태계 변화와 어업 (Changes in Marine Ecosystem according to Climate Change and Fishery)

  • 홍선기
    • 생태와환경
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    • 제47권4호
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    • pp.302-311
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    • 2014
  • Global climate change is significant issue in marine ecosystem and fishery market. According to rising of both seawater temperature and sea-level, global fishery environment and marine ecosystem are changing drastically. Moreover, over-exploitation in fishery areas is the most important issue in the marine ecosystem conservation. In analysis and statistics of global network, major fish populations are decreasing very fastly, but fish catch are increasing annually. It means balance between product and consume is not appropriate in the global market. China as emerging new fish consumer in the world is strongly developing fishery industry and technology. In this paper, I try to review a relationship between marine ecosystem and climate change in global scale according to references. I also suggested possibility of sustainable global fishery in changing marine ecosystem by analysis of some related reports of international global fishery.

GAS-COOLED FAST REACTORS_DHR SYSTEMS, PRELIMINARY DESIGN AND THERMAL- HYDRAULIC STUDIES

  • Malo, J.Y.;Bassi, C.;Cadiou, T.;Blanc, M.;Messie, A.;Tosello, A.;Dumaz, P.
    • Nuclear Engineering and Technology
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    • 제38권2호
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    • pp.129-138
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    • 2006
  • The Gas-cooled Fast Reactor (GFR) is one of the six reactor concepts selected within the framework of the Generation IV initiative and is the reference concept for the Commissariat $\grave{a}$ l'Energie Atomique $(CEA^1)$. Two reactor unit sizes have been considered: 600 MWth and 2400 MWth. As far as thermal-hydraulics is concerned, reactor decay heat removal (DHR) proves to be a major issue. The CEA has conducted exploratory design studies to address this issue and a reference solution for the 600MWth reactor has been recommended.

공급업체 선정에 대한 의사결정에 관한 연구 (An Empirical Study on Supplier Selection based on Analytic Hierarchy Process)

  • 이욱기
    • 디지털융복합연구
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    • 제3권2호
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    • pp.23-37
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    • 2005
  • On the situation cooperating with business partners on the supply chain, systematic decision making process is a critical issue for them. The two major issues of purchasing strategy such as selecting vendors and managing them are important part of their overall business activities. This study mainly focus on the former issue of the vendor selection. Through the empirical study, analytical hierarchy process (AHP) method was applied to select vendors among supplier vendors based on four selection criteria such as the level of quality, product on management ability, delivery, and price. The results of study showed the main criteria of vender selection was the ability of quality management. The vender selected based on AHP and the current selection method was different, but implicitly projected the dilemma situation between quality and price which occurs in decision making process of real life.

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전문용어기반 eDocument 관리 방안에 관한 연구 (A Study on eDocument Management Using Professional Terminologies)

  • 김명옥
    • 한국전자거래학회지
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    • 제7권2호
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    • pp.21-38
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    • 2002
  • Document retrieval (DR) has been a serious issue for long in the field of Office Information Management. Nowadays, our daily work is becoming heavily dependent on the usage of information collected from the internet, and the DR methods on the Web has become an important issue which is studied more than any other topic by many researchers. The main purpose of this study is to develop a model to manage business documents by integrating three major methodologies used in the field of electronic library and information retrieval: Metadata, Thesaurus, and Index/Reversed Index. In addition, we have added a new concept of eDocument, which consists of metadata about unit documents and/or unit document themselves. eDocument is introduced as a way to utilize existing document sources. The core concepts and structures of the model were introduced, and the architecture of the eDocument management system has been proposed. Test (simulation) result of the model and the direction for the future studies were also mentioned.

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공급업체 선정에 대한 의사결정에 관한 연구 (An Empirical Study on Supplier Selection based on Analytic Hierarchy Process)

  • 이욱기;김주완
    • 한국디지털정책학회:학술대회논문집
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    • 한국디지털정책학회 2005년도 추계학술대회
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    • pp.367-381
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    • 2005
  • On the situation cooperating with business partners on the supply chain, systematic decision making process is a critical issue for them. The two major issues of purchasing strategy such as selecting vendors and managing them are important part of their overall business activities. This study mainly focus on the former issue of the vendor selection. Through the empirical study, analytical hierarchy process (AHP) method was applied to select vendors among supplier vendors based on four selection criteria such as the level of quality, product on management ability, delivery, and price. The results of study showed the main criteria of vender selection was the ability of quality management. The vender selected based on AHP and the current selection method was different, but implicitly projected the dilemma situation between quality and price which occurs in decision making process of real life.

  • PDF