• 제목/요약/키워드: disconnection

검색결과 409건 처리시간 0.029초

IPLAN을 이용한 UPFC 조류계산 모형 (UPFC model for power flow using IPLAN)

  • 국경수;김학만;전진홍;오태규;장병훈;추진부
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 1998년도 추계학술대회 논문집 학회본부A
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    • pp.316-318
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    • 1998
  • This paper presents an approach that provides an equivalent initial operating condition of UPFC in load-flow study for stability analysis. The UPFC model for load-flow implemented by IPLAN in PSS/E is represented by an equivalent load injection. In doing so, the transmission line to which UPFC is connected is disconnected and the function of UPFC is represented by the equivalent load variation. This operating condition may not be adequate as an initial condition for subsequent dynamic simulation. The proposed approach provides a way of equivalencing UPFC load injection without line disconnection. The method was applied to a realistic power system for validity.

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보호기기 특성을 고려한 분산전원 연계 계통의 사고 배전선 판별 알고리즘 (Discrimination of the Faulted Feeder in Grid with Distributed Generations Considering the Characteristics of Protection Devices)

  • 김세근;김광호;장성일
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2004년도 추계학술대회 논문집 전력기술부문
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    • pp.243-245
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    • 2004
  • This paper proposes the discrimination method for the fault location, whether it is within the line where the distributed generation(DG) is integrated or out of the line (but sharing the same bus of the substation). In general, DG has to be disconnected from the grid when the fault occurs on the interconnected distribution feeder as soon as possible. However, the faults occured on the neighboring feeder would mistakenly cause the disconnection of the DG. For reliable operation of DG, DG should be sustained at the fault occurred on neighboring distribution feeders. The proposed identification method utilizes the impedance monitored from the DG and examines the coordination of overcurrent relay of the distribution system. This paper describes how the proposed method to identify the faulted feeder and how the method can be utilized.

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Mobile Client-Server System for Real-time Continuous Query of Moving Objects

  • Kim, Young-Choon;Joo, Hae-Jong;Kim, Young-Baek;Rhee, Sang-Yong
    • International Journal of Fuzzy Logic and Intelligent Systems
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    • 제11권2호
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    • pp.95-102
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    • 2011
  • In this paper, a Mobile Continuous Query Processing System (MCQPS) is designed to solve problems related to database hoarding, maintenance of shared data consistency, and optimization of logging. These problems are caused by weak connectivity and disconnection of wireless networks inherent in mobile database systems under mobile client-server environments. We show the superiority of the proposed MCQPS by comparing its performance to the Client-Intercept-Server (C-I-S) model. In addition, several experimental results show the effectiveness of our proposed indexing structure and methodology for real-time continuous queries.

분산전원이 연계된 배전 계통의 고장 선로 구분 (Identification of the faulted Feeder it Distribution Networks with Distributed Generations)

  • 김세근;김광호;장성일;강용철
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2004년도 하계학술대회 논문집 A
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    • pp.257-259
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    • 2004
  • This paper proposes the identification method for the faulted feeder, where it identify whether the faulted feeder is the DG-connected feeder or the neighboring feeder (but sharing the same bus of the substation). In general, DG has to be disconnected from the grid when the fault occurs on the interconnected distribution feeder as soon as possible. However, the faults occured on the neghboring feeder would mistakenly cause the disconnection of the DG. For reliable operation of DG, DG should be sustained at the fault occurred on neighboring distribution feeders. The proposed identification method utilizes the impedance monitored from the DG and examines the coordination of overcurrent relay of the distribution system. This paper describes how the proposed method to identify the faulted feeder and how the method can be utilized.

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엣지 컴퓨팅 시장 동향 및 산업별 적용 사례 (Edge Computing Market Trends and Application Scenarios)

  • 신성식;민대홍;안지영;김성민
    • 전자통신동향분석
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    • 제34권2호
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    • pp.51-59
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    • 2019
  • Edge computing, which is computing on the edge of the network, is becoming a market value as a means of overcoming the fear of communication disconnection and delay reduction, which are the technical weaknesses of cloud computing. Edge computing is continuously expanding applications in various applications such as safety industry, smart factories, autonomous vehicles, mobile communications, and AR/VR. Looking at edge computing trends from Microsoft, IBM, HPE, and Dell EMC, current edge computing must be understood as an integral binding technology and not as a simple complement to the cloud. This paper examines market trends in edge computing and analyzes the impact of edge computing on major related industries.

Elimination of Screen-Flickering Phenomenon in Multi-Function Display During Flight of Fixed-Wing Aircraft

  • Kwon, Jung-Hyuk;Kwon, Ik-Hyun;Beak, Jun-Ho;Jang, Geun-Hyung;Lee, Wang-Sang
    • 항공우주시스템공학회지
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    • 제15권2호
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    • pp.45-51
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    • 2021
  • In this study, we aim to eliminate the flickering phenomenon in multi-function display (MFD) units during the flight of fixed-wing aircraft. To execute flight missions effectively, the video signals transmitted to MFDs must provide information accurately and seamlessly. Therefore, a method for addressing the flickering phenomenon-including cause analysis and failure diagnosis-is adopted; specifically, a wiring configuration with a direct connection between the video signal cables and with a short cable length is adopted. The proposed method is experimentally verified using a flight test.

COVID-19 유행 시기의 조현병 환자 지원 (Supporting Patients With Schizophrenia in the Era of COVID-19)

  • 김성완
    • 대한조현병학회지
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    • 제24권2호
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    • pp.45-51
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    • 2021
  • The coronavirus disease 2019 (COVID-19) pandemic has drastically impacted our society and health care system. People with schizophrenia are more vulnerable to this burden of illness and related societal changes. In addition, they are more susceptible to the transmission of COVID-19 and have a significantly higher mortality rate compared to the general population. In a recent study, vaccinated patients with schizophrenia showed a greatly decreased mortality level similar to that of the general population. However, patients with schizophrenia were less likely to be vaccinated. Mental health professionals should provide them with appropriate information on prevention strategies against COVID-19 and vaccination. Long-lasting social distancing and social disconnection can make people with schizophrenia more vulnerable to loneliness and depression. Furthermore, patients with schizophrenia may face challenges continuing psychiatric treatment due to the COVID-19 pandemic. Social support and suitable mental health services using novel technologies should be developed and provided to patients with schizophrenia.

A Post Smoothing Algorithm for Vessel Segmentation

  • Li, Jiangtao;Lee, Hyo Jong
    • 한국정보처리학회:학술대회논문집
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    • 한국정보처리학회 2009년도 추계학술발표대회
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    • pp.345-346
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    • 2009
  • The segmentation of vessel including portal vein, hepatic vein and artery, from Computed Tomography (CT) images plays an important role in the therapeutic strategies for hepatic diseases. Representing segmented vessels in three dimensional spaces is extremely useful for doctors to plan liver surgery. In this paper, proposed method is focused on smoothing technique of segmented 3D liver vessels, which derived from 3D region growing approach. A pixel expand algorithm has been developed first to avoid vessel lose and disconnection cased by the next smoothing technique. And then a binary volume filtering technique has been implemented and applied to make the segmented binary vessel volume qualitatively smoother. This strategy uses an iterative relaxation process to extract isosurfaces from binary volumes while retaining anatomical structure and important features in the volume. Hard and irregular place in volume image has been eliminated as shown in the result part, which also demonstrated that proposed method is a suitable smoothing solution for post processing of fine vessel segmentation.

중국의 2021년중재법 개정안과 그 시사점 (A Study of Recent Trend and Revision Draft of the Chinese Arbitration Law)

  • 이양;김용길
    • 한국중재학회지:중재연구
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    • 제31권4호
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    • pp.29-49
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    • 2021
  • The Chinese Arbitration Law came into force in 1995 and has been implemented for 26 years. As a party to the New York Convention, there are many contradictions and conflicts between the Chinese Arbitration Law and the New York Convention on the issue of ad hoc arbitration, and this institutional disconnection can bring about problems such as misalignment of arbitration powers. On July 30, 2021, China's Ministry of Justice published a draft of the revised Arbitration Law for public consultation, and the draft has generated a lively debate among the public. This article explores the reasonable and inadequate points of the draft of Arbitration Law in light of the recent trends in the use of commercial arbitration in China, the COVID-19, the Free Trade Zone, and the relationship between the Civil Code and the Arbitration Law.

이동 클라이언트/서버 컴퓨팅환경에서의 캐싱 및 동시성 제어 (Caching and Concurrency Control in a Mobile Client/Sever Computing Environment)

  • 이상근;황종선;이원규;유헌창
    • 한국정보과학회논문지:소프트웨어및응용
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    • 제26권8호
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    • pp.974-987
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    • 1999
  • 이동 컴퓨팅 환경에서 자주 접근하는 데이터에 대한 캐싱은 무선 채널의 좁은 대역폭에서 경쟁을 줄일 수 있는 유용한 기술이다. 그러나, 트랜잭션 캐시 일관성을 지원하는 전통적인 클라이언트/서버 전략은 클라이언트와 서버간에 많은 양의 통신을 필요로 하기 때문에 이동 클라이언트/서버 컴퓨팅 환경에서는 적절하지 않다. 본 논문에서는 브로드캐스트-기반 캐시 무효화 정책을 사용하면서 트랜잭션 캐시 일관성을 지원하는 OCC-UTS (Optimistic Concurrency Control with Update TimeStamp) 프로토콜을 제안한다. 접근한 데이터에 대한 일관성 검사 및 완료 프로토콜은 캐시 무효화 과정의 내부 과정으로 완전 분산 형태로 효율적으로 구현되며, 일관성 체크의 대부분이 이동 클라이언트에서 수행된다. 또한, 분석 모델에 기반한 성능 비교를 통해, 본 논문에서 제안하는 OCC-UTS 프로토콜이 다른 경쟁 프로토콜보다 높은 트랜잭션 처리율을 얻으며, 데이터 항목을 자주 접근하면 할수록 지역 캐시를 사용하는 OCC-UTS 프로토콜이 더 효율적임을 보인다. 이동 클라이언트의 접속 단절에 대해서는 무효화 브로드캐스트 윈도우를 크게 하여 접속 단절에 적절히 대처할 수 있다.Abstract In a mobile computing environment, caching of frequently accessed data has been shown to be a useful technique for reducing contention on the narrow bandwidth of the wireless channels. However, the traditional client/server strategies for supporting transactional cache consistency that require extensive communications between a client and a server are not appropriate in a mobile client/server computing environment. In this paper, we propose a new protocol, called OCC-UTS (Optimisitic Concurrency Control with Update TimeStamp), to support transactional cache consistency in a mobile client/server computing environment by utilizing the broadcast-based solutions for the problem of invalidating caches. The consistency check on accessed data and the commitment protocol are implemented in a truly distributed fashion as an integral part of cache invalidation process, with most burden of consistency check being downloaded to mobile clients. Also, our experiments based on an analytical model substantiate the basic idea and study the performance characteristics. Experimental results show that OCC-UTS protocol without local cache outperforms other competitor protocol, and the more frequent a mobile client accesses data items the more efficient OCC-UTS protocol with local cache is. With respect to disconnection, the tolerance to disconnection is improved if the invalidation broadcast window size is extended.