• 상하수도학회지
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• 제27권1호
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• pp.1-10
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• 2013

Major issues in water supply service have changed from expansion of service area to improvement of service quality, i.e., water quality and safety, and early response to emergency situation. This change in the service concept triggers the perceptions of limitation with the current centralized water supply system and of necessities of decentralized (distributed) water supply system (DWSS), which can make up the limitations. DWSS can reduce the possibility of water supply outage by establishing multiple barriers such as emergency water supply system, and secure better water quality by locating treatment facilities neighboring consumers. On the other hand, fluctuation of water demand will be increased due to the reduced supply area, which makes difficult to promptly respond the fluctuating demand. In order to supplement this, hybrid water supply system was proposed, which combined DWSS with conventional water supply system using distributing reservoir to secure the stability of water supply. The Optimal connection point of DWSS to existing water supply network in urban area was determined by simulating a supply network using EPANET. Optimal location of decentralized water treatment plant (or connection point) is a nodal point where changes in pressure at other nodal points can be minimized. At the same time, the optimal point should be selected to minimize hydraulic retention time in supply network (water age) to secure proper water quality. In order to locate the point where these two criteria are satisfied optimally, Distance measure method, one of multi-criteria decision making was employed to integrate the two results having different dimensions. This methodology can be used as an efficient decision-support criterion for the location of treatment plant in decentralized water supply system.

• Journal of Power Electronics
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• 제16권6호
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• pp.2315-2326
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• 2016

This paper discusses the elimination of DC voltage deviation and the enhancement of load current sharing accuracy in multi-terminal high voltage direct current (MT-HVDC) systems. In order to minimize the power line losses in different parallel network topologies and to insure the stable operation of systems, a decentralized control method based on a modified droop control is presented in this paper. Averaging the DC output voltage and averaging the output current of two neighboring converters are employed to reduce the congestion of the communication network in a control system, and the decentralized control method is implemented. By minimizing the power loss of the cable, the optimal load current sharing proportion is derived in order to achieve rational current sharing among different converters. The validity of the proposed method using a low bandwidth communication (LBC) network for different topologies is verified. The influence of the parameters of the power cable on the control system stability is analyzed in detail. Finally, transient response simulations and experiments are performed to demonstrate the feasibility of the proposed control strategy for a MT-HVDC system.

• 한국통신학회논문지
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• 제40권2호
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• pp.253-263
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• 2015

최근 다수의 후 순위 사용자(Secondary User)가 각각의 검출 결과를 융합 센터(Fusion Center)에 보고하여 대역 검출의 성능을 향상시키기 위한 협력 대역 검출 기법이 이루어지고 있다. 또한 선 순위 사용자(Primary User)에게 할당된 주파수 대역을 융합 센터가 공유하는 인지 무선(Cognitive Radio)기술이 개발되고 있다. 이 논문에서는 분산 협력 대역 검출 환경에서 후 순위 사용자의 검출 정보가 융합 센터로 보고되는 채널의 오류 확률을 고려한 기존 분산 협력 대역 검출 기법의 성능 저하를 보완하는 새로운 분산 협력 대역 검출 기법을 제안하였다. 또한 분산 협력 대역 검출 기법의 오류 확률을 최소화 하는 검출 문턱값의 최적화 방법을 수식의 유도를 통해 제안하였다. 최적의 검출 문턱값은 분산 협력 대역 검출의 성능을 최대화 하는 것을 확인하였다.

• 한국컴퓨터정보학회논문지
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• 제27권5호
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• pp.127-138
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• 2022

본 논문에서는 금융권 DID(Decentralized Identity) 서비스 체계의 표준 방식을 준수하는 가운데 체계적인 검증 방식을 통하여 개인 정보나 자격 증명을 유연하게 제어할 수 있는 블록체인 기반의 DID 서비스인 FinDID(Financial Decentralized IDentity)를 제시한다. DID는 특정 인증기관 없이 탈중앙화 환경에서 활용하는 신원 관리 체계이며, 사용자가 자신의 정보를 제어할 수 있는 기술로서 사용자 자신의 개인정보에 대한 자기 주권화를 실현할 수 있다. FinDID을 통하여 사용자는 자신의 여러 개인정보를 인증하는 크리덴셜을 발급자에게 발급받아 개인 전자지갑을 이용해 타겟금융 서비스가 필수적으로 요구하는 클레임만을 크리덴셜에서 선택하여 프레젠테이션을 생성하고, 이를 금융 서비스에게 제출하여 자신의 서비스 이용자격을 부여받는다. FinDID는 전자지갑, 크리덴셜 발급자, 크리덴셜 저장소 그리고 DID 관리 컨트랙트 및 크리덴셜 관리 컨트랙트를 포함하는 DID 서비스 및 이러한 서비스 체계를 이용하는 금융서비스로 구성된다. DID 서비스는 각 사용자의 DID를 관리하고 관련된 신원 관리체계의 모든 검증과정을 지원한다.

• Bulletin of the Korean Chemical Society
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• 제24권3호
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• pp.279-284
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• 2003

The One Pass Method (OPM) previously presented for the identification of single input single output systems is used to estimate the parameters of a Decentralized Control System (DCS). The OPM is a linear and therefore a simple estimation method. All of the calculations are performed in one pass, and no initial parameter guess, iteration, or powerful search methods are required. These features are of interest especially when the parameters of multi input-output model are estimated. The benefits of the OPM are revealed by comparing its results against those of two recently published methods based on pulse testing. The comparison is performed using two databases from the literature. These databases include single and multi input-output process transfer functions and relevant disturbances. The closed loop responses of these processes are roughly captured by the previous methods, whereas the OPM gives much more accurate results. If the parameters of a DCS are estimated, the OPM yields the same results in multi or single structure implementation. This is a novel feature, which indicates that the OPM is a convenient and practice method for the parameter estimation of multivariable DCSs.

• 한국지능시스템학회논문지
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• 제12권1호
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• pp.80-84
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• 2002

본 논문은 2자유도 실험용 헬리콥터 시스템의 제어를 위한 분산 제어기 설계 기법을 제안한다. 분산제어기법은 특히 대규모 제어 시스템에 적합하다고 알려져 있다. 본 논문에서는 Lyapunov 안정도 설계 방법을 이용하여 상호 연결된 TS 퍼지 시스템의 안정도 조건을 유도하고 선형 행렬 부등식을 이용하여 제어기 설계 조건을 공식화한다. 제안된 방법의 유용성을 검증하기 위해, 컴퓨터 시뮬레이션뿐 만 아니라 실험을 통해 그 결과를 도출한다.

• KIEAE Journal
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• 제6권3호
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• pp.3-10
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• 2006

As environmental problems and water-shortage phenomenon become a global issue, many states look for the effective method to use water resources. So, decentralized rainwater management is recognized as a new water management system that rainwater can be infiltrated and used on-site. But it is little difficult to build a park, lake, and forest for evaporating rainwater in city because the land price of city is very high. In order to build an excellent infiltration system for a dwelling and a park in Korea, KICT has developed Linear infiltration system. This infiltration system is consist of first flush treatment, storage and infiltration, overflow control system. These elements are connected closely and working as a combined system. A storm sewer can be changed by the linear infiltration system. This study is to make design guideline using Linear infiltration system in apartment house. So ATV-DVWK-M13, FLL and present condition of Korean rainwater system were analyzed and the guidelines direction were set up. Through this study, a foundation is prepared to build the decentralized rainwater management of apartment house.

• ETRI Journal
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• 제42권6호
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• pp.872-885
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• 2020

Distributed consensus requires the consent of more than half of the congress to produce irreversible results, and the performance of the consensus algorithm deteriorates with the increase in the number of nodes. This problem can be addressed by delegating the agreement to a few selected nodes. Since the selected nodes must comply with the Byzantine node ratio criteria required by the algorithm, the result selected by any decentralized node cannot be trusted. However, some trusted nodes monopolize the consensus node selection process, thereby breaking decentralization and causing a trilemma. Therefore, a consensus node selection algorithm is required that can construct a congress that can withstand Byzantine faults with the decentralized method. In this paper, an algorithm based on the Byzantine agreement among decentralized agents to facilitate agreement between decentralization nodes is proposed. It selects a group of random consensus nodes per block by applying the proposed proof of nonce algorithm. By controlling the percentage of Byzantine included in the selected nodes, it solves the trilemma when an arbitrary node selects the consensus nodes.

• 한국정보과학회:학술대회논문집
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• 한국정보과학회 1999년도 가을 학술발표논문집 Vol.26 No.2 (2)
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• pp.101-103
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• 1999

Decentralized 정보는 여러 도메인에 대한 heterogeneous한 독립적인 정보가 자율적으로 존재하며 이들 정보간의 관계성의 고려한 전체에 대한 global view가 존재하지 않기 때문에 inter-domain에 대한 마이닝을 수행하는데 어려움이 있다. 본 연구에서는 intra-domain knowledge discovery, intra 및 inter-domain problem solving method라는 접근방법으로, decentralized 데이터 환경에서 문제 해결에 필요한 정보 추출을 위한 데이터 tailoring과 분산 데이터에 대한 목표-지향 데이터마이닝(goal-oriented data-mining)을 통해 문제 해결을 위해 필요한 지식을 생성하고 이들 간의 관련 정보를 탐색하여 문제를 해결하는 프레임워크를 제안한다. 특히, 생성된 지식간의 협동 문제 처리를 멀티 에이전트 패러다임을 이용하기로 한다. 제안 프레임워크는 산재되어 있는 데이터들로부터 문제 해결에 유용한 지식 차원의 정보를 추출해내고 생성된 지식을 바탕으로 각 도메인 정보에 대한 개별적인 사용뿐 만 아니라 서로 cooperation을 통한 문제 해결을 지원함으로써, 개방된 분산 환경하에 decentralized 되어 있는 여러 도메인 정보를 보다 효율적으로 활용할 수 있는 새로운 형태의 문제 해결 방법이라고 할 수 있다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.1909-1914
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• 2004

Passive velocity field control (PVFC) was previously developed for fully mechanical systems, in which the motion task was specified behaviorally in terms of a velocity field, and the closed-loop was passive with respect to a supply rate given by the environment input. However the PVFC was only applied to a single manipulator, the proposed control law was derived geometrically, and the geometric and robustness properties of the closed-loop system were also analyzed. In this paper, we propose a method to apply a decentralized control algorithm to cooperative 3-wheeled mobile robots whose subsystem is under nonholonomic constraints and which convey a common rigid object in a horizontal plain. Moreover it is shown that multiple robot systems ensure stability and the velocities of augmented systems convergence to a scaled multiple of each desired velocity field for cooperative mobile robot systems.