• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2006년 제4회 한국유체공학학술대회 논문집
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• pp.313-316
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• 2006

As Decentralized Generation(DG) becomes more reliable and economically feasible, it is expected that a higher application of DG units would be interconnected to the existing grids. This new market penetration of DG technologies is linked to a large number of factors like technologies costs and performances, interconnection issues, safety, market regulations, environmental issues or grid connection constrains. Korea Electric Power Corporation (KEPCO) has researched performance characteristics of the 60k W class 1) basic start-up & shutdown operation analysis 2) interconnection test 3) MGT -absorption chiller-heater system in the local condition. Variations of heat recovery from exhaust gas has measured according to micro gas turbine output of 15, 30, 45, 60kW. From those results, the performance of the MGT-absorption chiller/heater system has been evaluated. The suggested strategy and experience for the evaluation of the distributed generation will be used for the introduction of other distributed generation technologies into the grid in the future.

• 한국정보처리학회논문지
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• 제3권3호
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• pp.591-607
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• 1996

MuX서버는 다양한 멀티미디어 응용 프로그램 개발을 지원하기 위하여 멀티미디어 스트림의 생성 , 복제, 분할, 합성, 접합등의 멀티미디어 입출력을 위한 객체지향적이고 일관적인 인터페이스를 제공한다. 본 논문에서는 MuX의 요소객체를 이용하여 컴퓨터 영상회의 프로그램을 개발할 경우에 가능한 분산형과 집중형연결 구조에 대하여 지연, 동기 등 멀티미디어관련 성능에 따른 장단점을 비교 분석한다.

• International journal of advanced smart convergence
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• 제12권4호
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• pp.55-62
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• 2023

Slotted-Aloha (S-Aloha) has been widely employed in random access networks owing to its simple implementation in a distributed manner. To enhance the throughput performance of the S-Aloha, connection-based slotted-Aloha (CS-Aloha) has been proposed in recent years. The fundamental principle of the CS-Aloha is to establish a connection with a short-sized request packet before transmitting data packets. Subsequently, the connected node transmits long-sized data packets in a batch of size M. This approach efficiently reduces collisions, resulting in improved throughput compared to the S-Aloha, particularly for a large M. In this paper, we address the short-term fairness of the CS-Aloha, as quantified by Jain's fairness index. Specifically, we evaluate how equitably the CS-Aloha allocatestime slots to all nodes in the network within a finite time interval. Through simulation studies, we identify the impact of system parameters on the short-term fairness of the CS-Aloha and propose an optimal transmission probability to support short-term fairness.

• 조명전기설비학회논문지
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• 제26권7호
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• pp.70-76
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• 2012

In general, the unidirectional power flow is normal in distribution feeders before activation of distributed power source such as PV. However, the interactive power flow is likely to occur in case of the power system under distributed generation. This interactive power flow can cause an unexpected effect on convectional protection coordination systems designed based only on the unidirectional power flow system. When the power line system encounters a problem, the interactive power flow can be a contributed current source and this makes the fault current bigger or smaller compared to the unidirectional case. The effect of interactive power flow is varied depending on the location of the point to ground fault, relative location of the PV, and connection method. Therefore it is important to analyse characteristics of fault current and interactive flow for various transformer connection and location of the PV. This paper proposes a method of improved protection coordination which can be adopted in the protective device for customers in distribution feeders interconnected with the PV. The proposed method is simulated and analysed using PSCAD/EMTDC under various conditions.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2012년도 추계학술대회
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• pp.389-391
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• 2012

현재에 있어서 무선네트워크의 중요성은 갈수록 높아지고만 있고 데이터를 처리함에 있어서 유선이 아닌 무선을 이용함으로써 사용자들의 간편성 및 신속성이 보장되어지고 있다. 하지만 현재 제안되고 있는 일반적인 무선네트워크인 ZigBee를 이용한 무선네트워크는 데이터 전송에 있어서 영상 등의 대용량의 데이터를 전송 할 경우 유선에 비해 디바이스 간 데이터 처리속도가 매우 낮다. 따라서 본 논문에서는 이러한 문제점을 극복하기 위해 ZigBee와 WiMedia의 결합을 통해 기존 무선 네트워크인 ZigBee를 이용하면서 디바이스간의 통신 방법 개선 및 통신속도향상 그리고 채널 상황에 능동적으로 대처할 수 있는 Distributed MAC프로토콜 기반의 릴레이 협력통신 방안을 제안한다.

• Steel and Composite Structures
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• 제7권4호
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• pp.303-320
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• 2007

The objective of this study is to clarify the structural features of members consisting of connection, as a series of the previous study on the CFT column-to-beam tensile connection with combined cross diaphragm. This connection has the merits that the stress is distributed evenly on the beam flange and the diaphragm and the stress concentration is reduced, by improving the stress transfer route and restraining abrupt deformation of diaphragm. The finite element analysis was performed to find out the stress transfer through sleeve which is an important member of the connection with combined cross diaphragm. The length and thickness of sleeve were used as variables for the analysis. As the analysis results, the length and thickness of sleeve didn't influence on the capacity of the connection and played a role of a medium to transfer the stress from the diaphragm to the filled concrete. It is proposed that the appropriate length of sleeve be the same value as the diameter of sleeve and the appropriate ratio of sleeve diameter to sleeve thickness be 20. Two equations for evaluation of the load-carrying capacity of the connection were also proposed through the modification of the evaluation equation suggested in the previous study.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제9권10호
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• pp.3771-3788
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• 2015

This paper studies the distributed energy efficient resource management in the Internet of Things (IoT). Wireless communication networks support the IoT without limitation of distance and location, which significantly impels its development. We study the communication channel and energy management in the wireless communication network supported IoT to improve the ability of connection, communication, share and collaboration, by using the game theory and distributed learning algorithm. First, we formulate an energy efficient neighbor collaborative game model and prove that the proposed game is an exact potential game. Second, we design a distributed energy efficient channel selection learning algorithm to obtain the global optimum in a distributed manner. We prove that the proposed algorithm will asymptotically converge to the global optimum with geometric speed. Finally, we make the simulations to verify the theoretic analysis and the performance of proposed algorithm.

• 정보처리학회논문지C
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• 제12C권3호
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• pp.449-456
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• 2005

광 버스트 스위칭(OBS) 기술은 광 회선 스위칭에서 발생하는 자원의 비효율적인 사용을 개선시키며, 광 패킷 스위칭에서 해결하여야 할 과제인 광 버퍼링의 요구사항을 최소화한다. GSMP는 제어기와 레이블 스위치 사이에서 연결, 구성, 성능, 장애관리 및 동기화 기능을 제공하는 개방형 인터페이스이다. OBS 망을 위한 GSMP 개방형 인터페이스 도입은 OBS 망의 전달평면과 제어평면의 분리를 실현하여 OBS 스위치의 구현을 단순화한다. 본 논문에서는 GSMP 개방형 인터페이스가 적용된 OBS 망의 연결, 구성, 성능 및 장애관리를 위한 관리객체를 정의하였으며, 이들 관리정보가 관리 기능별로 OBS 스위치와 제어기에 분산되어 탑재되는 분산 망 관리 모델을 제안하였다. GSMP와 OBS 관리객체를 수용한 망 관리 기능의 구현을 통하여 GSMP 개방형 인터페이스가 적용된 OBS 망에서의 분산 망 관리 모델을 이용한 연결관리의 실현성을 확인하였다.

• 통합자연과학논문집
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• 제16권4호
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• pp.139-145
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• 2023

Due to changes in the distribution system and increased demand for renewable energy, interest in technology to increase the limit capacity of distributed energy grid connection using grid flexible resources is also increasing. Recently, the distribution system system is changing due to the increase in distributed power from renewable energy, and as a result, problems with the limited capacity of the distribution system, such as waiting for renewable energy to connect and increased overload, are occurring. According to the power generation facility status report provided by the Korea Power Exchange, of the total power generation capacity of 134,020 MW as of 2021, power generation capacity through new and renewable energy facilities is 24,855 MW, accounting for approximately 19%, and among them, power generation through solar power accounts for a total portion of the total. It was analyzed that the proportion of solar power generation facilities was high, accounting for 75%. In the future, the proportion of new and renewable energy power generation facilities is expected to increase, and accordingly, an efficient operation plan for the distribution system is needed. Advanced country-type NWAs that can integrate the operation and management of load characteristics for each line of the distribution system, power distribution, regional characteristics, and economic feasibility of distributed power in order to improve distribution network use efficiency without expanding distribution facilities due to the expansion of renewable energy. An integrated operating system is needed. In this study, in order to improve the efficiency of distribution network use without expanding distribution facilities due to the expansion of renewable energy, we developed a method that can integrate the operation and management of load characteristics for each line of the distribution system, power distribution, regional characteristics, and economic feasibility of distributed power. We want to develop an integrated operation system for NWAs similar to that of advanced countries.

• 전자공학회논문지
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• 제52권6호
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• pp.144-150
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• 2015

본 논문은 분산된 센서 디바이스의 리소스 오브젝트 연동 서비스 제공 시스템에 관한 것으로 서비스 전달 플랫폼을 기반으로 한다. 시스템은 서비스 전달 플랫폼(SDP: Service Delivery Platform)과 프록시로 구성되어 있다. 서비스 전달 플랫폼은 분산된 서비스 기능을 인에이블러로 설정하며 인에이블러들의 조합으로 융합서비스를 생성한다. 또한 생성된 서비스를 분산 환경에서 전달하는 역할을 한다. 프록시는 분산된 디바이스들과 서비스 전달 플랫폼을 연결하도록 설정되며 서비스 전달 플랫폼이 분산된 디바이스를 자원으로 인식하여 인에이블러로 정의할 수 있도록 한다. 개발된 시스템을 통하여 분산된 센서 기능이 인에이블러로 정의되어 일반 서비스 기능과 동일한 형태로 융합서비스의 생성 및 전달에 사용될 수 있다.