• Journal of Digital Contents Society
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• v.6 no.1
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• pp.1-5
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• 2005

This paper describes the main characteristics of Grid Services based on OGSA and a Grid service for aggregating service data element(SDE)s. In order to build a Grid Service, it needs to consider a systematic building approach from the high-level software architecture that represents the main system components and their interactions. The purpose of this paper is to design and implement an extended service data aggregator service in which SDE is a basic unit for collecting resource information. A GT3 based service data aggregator service is extended to apply the multiple collections based storage scheme for maintaining persistently SDEs with a XML DBMS Xindice. To provide efficient aggregating service for service data elements, which is running under wide area environment like Internet, the aggregator service is asynchronously operated by notification mechanism.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2003.09a
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• pp.28-31
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• 2003

In the present work, a main purpose is to propose a fuzzy integral-based aggregation framework to complementarily combine partial information due to lack of completeness. Based on Choquet integral (CI) viewed as monotone expectation, we take into account complementary, non-interactive, and substitutive aggregations of different sources of defective information. A CI-based system representing upper, conventional, and lower expectations is designed far handling three aggregation attitudes towards uncertain information. In particular, based on Choquet integrals for belief measure, probability measure, and plausibility measure, CI$\_$bi/-, CI$\_$pr/ and CI$\_$pl/-aggregator are constructed, respectively. To illustrate a validity of proposed aggregation framework, multiple matching systems are developed by combining three simple individual template-matching systems and tested under various image variations. Finally, compared to individual matchers as well as other traditional multiple matchers in terms of an accuracy rate, it is shown that a proposed CI-aggregator system, {CI$\_$bl/-aggregator, CI$\_$pl/-aggregator, Cl$\_$pl/-aggregator}, is likely to offer a potential framework for either enhancing completeness or for resolving conflict or for reducing uncertainty of partial information.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.12
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• pp.2221-2224
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• 2011

During an emergency due to a shortage of power, a load aggregator (LA) can use the demand response operation system to deploy demand response resources (DRRs) through various demand response (DR) programs. This paper introduces the demand response operation system for a load aggregator to manage various demand response resources in a smart grid environment.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.596-598
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• 2015

본 논문에서는 전기자동차 충전 시 예상되는 선로 과부하 문제와 전압강하 문제를 해결하기 위해 연료전지를 이용한 충전 Aggregator 알고리즘을 제안한다. 충전Aggregator 알고리즘은 충전부하 투입 알고리즘과 충전부하 제거 알고리즘으로 구성되어 있다. 충전부하 투입 알고리즘은 충전부하 투입 전 선로전력과 전압강하를 예측하여 예측 된 값들이 허용범위를 초과하지 않을 경우 충전을 시작하는 알고리즘 이고 충전부하 제거 알고리즘은 전기자동차 충전 중 일반부하의 증가로 문제 발생 시 충전부하를 제거하는 알고리즘이다. 제안된 알고리즘은 PSCAD/EMTDC를 이용해서 연료전지가 연계된 특정지역의 배전계통을 모델링하여 검증하였다.

• Journal of Electrical Engineering and Technology
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• v.11 no.5
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• pp.1049-1056
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• 2016

• Journal of Electrical Engineering and Technology
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• v.8 no.6
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• pp.1269-1275
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• 2013

Recently, many studies have suggested that an electric vehicle (EV) is one of the means for increasing the reliability of power systems in new energy environments. EVs can make a contribution to improving reliability by providing frequency regulation in power systems in which the Vehicle-to-Grid (V2G) technology has been implemented and, if economically viable, can be helpful in increasing power system reliability. This paper presents a stochastic method for optimal coordination of charging and frequency regulation decisions for an EV aggregator using the Least Square Monte-Carlo (LSMC) with modeling of electricity price uncertainty. The LSMC can be used to assess the value of options based on electricity price uncertainty in order to simultaneously optimize the scheduling of EV charging and regulation service for the EV aggregator. The results of a numerical example show that the proposed method can significantly improve the expected profits of an EV aggregator.

• The Journal of the Korea Contents Association
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• v.4 no.4
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• pp.99-106
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• 2004

This paper describes main characteristics of Grid Services based on OGSA and a service component for aggregating service data element. In order to build a Grid Service for SOA, it needs to consider a systematic approach from the high-level software architecture of a system that describes the main system components and their interactions. The purpose of this paper is to design and implement an extended service data aggregator service. To provide reliable aggregating service for service data elements, which is running under wide area environment like Internet, the aggregator service is operated asynchronously by notification mechanism.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.640-641
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• 2011

스마트그리드 환경하에서 플러그인 전기 자동차(PEV)는 새로운 도전이자 과제이다. 전 세계적으로 전기 자동차에 대한 관심이 높아지면서 PEV가 전력망에 미치는 영향에 관한 연구가 이루어지고 있다. 본 논문에서는 LA사업자(Load Aggregator)는 소비자들의 부하를 통합적으로 관리하여 에너지 비용을 최소화하며 인센티브 지급을 통한 V2G 서비스를 사용하여 피크 삭감을 유도한다. PEV 운영 비용 최소화와 부하 평탄화를 목적으로 하는 LA사업자에 의한 PEV 충전 부하 관리의 잠재적인 이점들을 평가하며, 최적 충전 제어 방식을 위하여 하루전 시장에서 충전 부하와 V2G 가능 용량을 예측하고 PEV 배터리를 분석하여 모델링하는 방법을 제시하였다. 사례연구에서는 다음의 세 가지 PEV 충전 시나리오 즉, 제어되지 않는 시나리오(퇴근 후 충전), TOU 요금제를 적용한 시나리오와 최적 충전 제어 시나리오에 대해 에너지 비용과 피크 수요 감축 측면에서 비교 평가하였다. 이는 향후 증가하는 PEV로 인한 계통의 경제성 평가 및 신뢰도 평가로 사용할 수 있을 것으로 사료된다.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.8
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• pp.1181-1186
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• 2017

The purpose of Demand Response is to reduce the cost of excessive resources and equipment by spontaneous load reductions at peak loads. Having enough power consumers participating in these schemes is key to achieving the goal. Demand Response Aggregator (DRA) is responsible for recruiting demand resources and managing them to participate in reducing the load. DRAs change the price elasticity of demand functions by providing incentives to demand response, thereby affecting price formation in the electricity market. In this paper, this process is modeled to analyze the relationship between DRA's strategic bidding and market outcomes and load reductions. It analyzes the results by applying to competition between DRAs, competition between DR and Gencos, and coexistence of DR load and non-DR load. It is noteworthy that we have found a phenomenon called the Balloon Effect.

• ETRI Journal
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• v.26 no.4
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• pp.351-359
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• 2004

Flow aggregation is a scalable method to provide quality of service (QoS) guarantees to a large number of flows economically. A round-robin scheduler is an efficient scheduling algorithm. We investigate flow aggregation using a round-robin scheduler and propose the use of periodic timer interrupts for rate control of the round-robin scheduler. The proposed flow aggregator is a single-stage scheduler compared to Cobb's two-stage flow aggregator consisting of an aggregator and non-aggregating scheduler. It is possible to implement flow aggregation in the existing routers with only a software upgrade. We also present a simulation study showing the delay behaviors of the proposed algorithm.