• 한국항해항만학회지
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• 제46권6호
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• pp.501-508
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• 2022

세계 디지털화의 흐름이 경제, 신원 인증, 물류 분야 등에서 블록체인 혹은 분산원장을 기반으로 한 탈중앙화 시스템 환경으로 변화하고 있다. 이에 맞추어 이내비게이션 서비스의 접근성에 있어서도 탈중앙화된 여러 해사 서비스 레지스트리(MSR)들로부터 공개 서비스를 검색할 수 있어야 한다는 요구사항이 도출되었다. 본 연구는 MSR 분산원장과 다수의 지역 MSR로 구성된 탈중앙화 MSR 환경을 기술하고, 이 환경에서 웹 브라우저 기반의 글로벌 이내비게이션 서비스를 검색할 수 있는 서비스 검색 시스템을 구현하였다. 동적으로 서비스 속성, 지역 정보, 자유 텍스트 검색 질의를 생성하여 MSR 분산원장에 등록된 검색 결과를 통해 유관 MSR과 서비스 접속 정보를 사용자에게 제공하는 탈중앙화 애플리케이션이다. 본 연구에선 구축된 탈중앙화 MSR 환경과 그 환경 내에서 서비스 검색을 수행하는 시스템을 실험하였고 이를 통해 가지는 장점 및 한계점에 대한 논의를 갖는다.

• Journal of Electrical Engineering and information Science
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• 제3권2호
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• pp.158-162
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• 1998

We study the decentralized stabilization problem of linear time-invariant large-scale interconnected systems with delays without any system structure. We obtain sufficient stability conditions for interconnected systems which are equivalent to disturbance attenuation of some scaled system. A decentralized output-feedback controller is obtained using standard H$\infty$ control theory. The obtained controller is delay-independent. We also obtain an observer for the interconnected system.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년 학술대회 논문집 정보 및 제어부문
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• pp.291-294
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• 2006

This paper presents a decentralized input-output feedback linearizing controller for a multi-machine power system. Firstly, the controller is designed using input-output feedback linearization for modified outputs. Then we present a guideline for selecting gains of the controller and parameters in the modified outputs. Simulations illustrate the effectiveness of the proposed control scheme and the selection guideline.

• 융합보안논문지
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• 제21권2호
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• pp.37-46
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• 2021

탈중앙화 신원증명(DID, Decentralized Identifier) 기술은 블록체인 기술을 이용하여 개인의 신원증명을 중앙시스템을 통하지 않고 개인이 소유한 정보를 통해 자신의 신원을 증명하는 기술이다. 본 논문에서는 탈중앙화 신원증명 기술을 이용한 출입통제 시스템을 제시하고자 한다. 탈중앙화 신원증명 기술을 이용한 출입통제 시스템(이하 DID 출입통제 시스템)은 사용자 자신의 스마트폰(모바일 사원증)에 저장되어 있는 본인의 정보를 통해 DID 블록체인 서버로부터 신원을 증명하고 증명된 신원이 출입통제 시스템에 등록된 사용자임을 확인되었을 때 출입을 할 수 있도록 구현된 시스템이다. 이를 통해 개인의 신원을 증명하기 위한 정보를 출입통제 시스템에 저장할 필요 없이 스마트폰(모바일 사원증)과 DID 블록체인 서버와의 신원증명 확인만으로 출입통제를 관리할 수 있다.

• 제어로봇시스템학회논문지
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• 제22권9호
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• pp.693-698
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• 2016

A decentralized control method is proposed to enable a group of robots to achieve maximum performance in multisensory target tracking while avoiding collision with the target. The decentralized control was designed based on navigation function formalism. The study showed that the multiple agent system converged to the positions providing the maximum performance by the decentralized controller, based on Lyapunov and Hessian theory. An exemplary simulation was given for a multiple agent system tracking a stationary target.

• International Journal of Internet, Broadcasting and Communication
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• 제13권1호
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• pp.26-36
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• 2021

The Internet was created as a decentralized and autonomous system of interconnected computer networks used for data exchange across mutually trusted participants. The element technologies on the Internet, such as inter-domain and intra-domain routing and DNS, operated in a distributed manner. With the development of the Web, the Web has become indispensable in daily life. The existing web applications allow us to form online communities, generate private information, access big data, shop online, pay bills, post photos or videos, and even order groceries. This is what has led to centralization of the Web. This centralization is now controlled by the giant social media platforms that provide it as a service, but the original Internet was not like this. These giant companies realized that the decentralized network's huge value involves gathering, organizing, and monetizing information through centralized web applications. The centralized Web applications have heralded some major issues, which will likely worsen shortly. This study focuses on these problems and investigates blockchain's potentials for decentralized web architecture capable of improving conventional web services' critical features, including autonomous, robust, and secure decentralized processing and traceable trustworthiness in tamper-proof transactions. Finally, we review the decentralized web architecture that circumvents the main Internet gatekeepers and controls our data back from the giant social media companies.

• Journal of Electrical Engineering and Technology
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• 제10권3호
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• pp.1335-1341
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• 2015

The utilization of electric vehicles has been suggested to support the frequency regulation of power system. Assuming that an intermediate aggregator exists, this study suggests a decentralized vehicle-to-grid operation scheme in which each vehicle-to-grid aggregator can behave independently of the power system operator. To implement this type of decentralized operation, this study adopts a price-based operation that has been proposed by many researches as an alternative operation scheme for the power system. In this environment, each vehicle-to-grid aggregator can determine its participation in vehicle-to-grid service in consideration of its residual energy of aggregated system and real-time market price. Consequently, the main purpose of this study is to verify whether or not the vehicle-to-grid power can effectively support the current frequency regulation function within the price-based operation scheme. Specifically, a frequency regulation method is proposed based on the real-time price signal, and a feedback controller for battery management is designed for decentralized vehicle-to-grid operation.

• International Journal of Automotive Technology
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• 제6권5호
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• pp.545-554
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• 2005

Passive velocity field control (PVFC) was previously developed for fully mechanical systems, in which the motion task was specified by behaviors in terms of a velocity field and the closed-loop was passive with respect to the 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 virtual passivity-based algorithm to apply decentralized control to multiple 3­wheeled mobile robotic systems whose subsystems are under nonholonomic constraints and 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 converge to a scaled multiple of each desired velocity field for cooperative mobile robot systems. Finally, the application of proposed virtual passivity-based decentralized algorithm via system augmentation is applied to trace a circle and the simulation results is presented in order to show effectiveness for the decentralized control algorithm proposed in this research.

• Journal of Electrical Engineering and Technology
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• 제7권2호
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• pp.141-150
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• 2012

The present study examines an efficient congestion management system compatible with the evolving environment. The key is to build an information model shared and exchanged for marketbased solutions to alleviate congestion. Traditional methods for congestion management can be classified into two categories, i.e., the centralized scheme and the decentralized scheme, depending on the extent to which the independent system operator (ISO) is involved in market participants' (MPs) activities. Although the centralized scheme is more appropriate for providing reliable system operation and relieving congestion in near real-time, the decentralized scheme is preferred for supporting efficient market operation. The minimum set of information between the ISO and MPs for decentralized scheme is identified: i) congestion-based zone, ii) Power Transfer Distribution Factors, and iii) transmission congestion cost. The mathematical modeling of the proposed information is expressed, considering its process of making effective use of information. Numerical analysis is conducted to demonstrate both cost minimization from the MP perspective and the reliability enhancement from the ISO perspective based on the proposed information exchange scheme.

• 제어로봇시스템학회논문지
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• 제6권5호
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• pp.333-338
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• 2000

This paper considers the decentralized control problem of linear time-invariant interconnected systems with delays. A decentralized output-feedback controller to obtain both stability and performance of the interconnected system is designed using the standard $H_\infty$ control theory, This paper provides sufficient conditions for such a controller to exist and provides an output feedback controller.