• 제어로봇시스템학회:학술대회논문집
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• 1990.10b
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• pp.878-883
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• 1990

There have been many approaches to solve the disturbance rejection problem in the control of LTI systems with state independent disturbances or possibly nonlinear state dependent disturbances. From the view point of each actuator, robot manipulators can be modeled as the second class of systems. With this model, M.Nakao et al. [1] introduced a decentralized control scheme based on interference estimation which is simple in its implementation and robust to the coupled dynamics and parameter variations. This paper systematically generalizes the control scheme to arbitrary finite dimensional LTI systems with disturbances. In doing so, we develop a disturbance observer theory for solving the disturbance rejection problem. We also present a discrete version of the theory with discussion of sampling and time-delay effects.

• Proceedings of the KSR Conference
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• 2005.05a
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• pp.843-848
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• 2005

Currently the train traffic control system is built wholly by one package construction. It is under variable circumstance such as variation of signalling equipment and station expansion. This condition reduces system reliability and availability. And the term of system change is longer than 10 years, so it is hard to update to the latest technology and the new function. In order to do the system should be replaced to new one completely. The step by step construction of ADS(Autonomous Decentralized System) is one of the solution. So the simulation of it on the real station help to find system requirement and verify good of online expansion and online test.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.49 no.6
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• pp.298-304
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• 2000

In this paper, we propose that the SCOPF be solved in a decentralized framework, consisting of regions, using a price-based mechanism. We first solve the distributed OPF problem to determine the maximum secure simultaneous transfer capability of each tie-line between adjacent regions by taking only the security constraints imposed on the tie-lines into account. And then, the regional SCOPF is performed using the conventional LP approach. A description on the inclusion of security constraints with distributed OPF algorithm will be given, folowed by a case study for Korea power system.

• Proceedings of the Korea Information Processing Society Conference
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• 2014.11a
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• pp.1183-1186
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• 2014

Our research is different form traditional to have some large LED screen grouping together to constitute multi-vision technique. In this paper, we purpose a method of using k-path diffusion method to build connect between the devices and find an optimal data transmission path. In second half of this paper, through practical application, we using this technique transmitting data successfully and achieving a simple Multi-vision effect. This technique possess smart devices and Wifi P2P's features, these features improve system's dynamic and decentralized processing ability make our technique has high scalability.

• Proceedings of the Korea Information Processing Society Conference
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• 2018.10a
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• pp.260-263
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• 2018

현재까지 공항에서의 체크인 시스템은 기본적으로 서버-클라이언트(Server-Client)방식으로 구동되어져왔다. 서버-클라이언트 방식에서 서버는 단일실패지점이기 때문에 천재지변이나 공격자에 의해 서버마비와 같은 문제가 생기면 체크인 시스템 전체가 마비될 수 있다. 뿐만 아니라 실제 해커에 의해 항공사 중앙 서버가 공격을 받게 되면, 서버가 관리하는 항공사 데이터들의 무결성이 훼손될 수도 있다. 따라서 단일 실패지점에 대한 위협을 제거함과 동시에 저장된 데이터들의 무결성을 유지하는 방법을 논의할 필요가 있다. 그 중 하나로 블록체인 기술을 이용한 탈중앙화 시스템(Decentralized System) 모델을 적용하는 방법이 있다. 본 논문에서는 스마트 계약을 이용한 블록체인 기반 공항 체크인 시스템에 대한 모델을 제안한다.

• International Journal of Computer Science & Network Security
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• v.21 no.8
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• pp.149-160
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• 2021

One of the most important inventions and developments in the digital world today is the healthcare system based on blockchain technology. Healthcare is an important field that requires the application of security mechanisms due to the sensitivity of patient data. The association of blockchain with healthcare contributed to achieving better security mechanisms than the traditional approach. The new approach operates in a decentralized system, which in turn, improves security in the healthcare environment. Consequently, blockchain technology has emerged as one of the most crucial solutions to security violations and challenges in the healthcare industry. This paper provides a comprehensive review of several experts' recent protection and detection approaches in this domain. It is also imperative to note that the paper focuses only on the recent techniques that have been published during 2017-2020. The sophisticated procedures have been investigated and discussed in terms of similarities and differences to highlight the significance of the protection needed to secure the healthcare environment.

• Journal of Korea Multimedia Society
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• v.24 no.6
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• pp.760-767
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• 2021

The identity verification is one of the most important technologies in online services. Many services in society are provided online, and the service is provided after confirming the user's identity. Users can do a lot of things online, but they also have side effects. Online digital information is easily manipulated and it is difficult to verify its authenticity, causing social confusion. Accordingly, there has been a movement for individuals to directly manage their identity information using DID. In this paper, we propose a system that can authenticate identity by directly adding own personal information and issuing an identifier using DID technology based on a private blockchain. Then, to verify the proposed system, the scenario is executed and verified.

• Proceedings of the Korea Information Processing Society Conference
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• 2020.05a
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• pp.214-217
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• 2020

2020년 1월 국내에 신종 코로나 바이러스의 확산으로 인해 보건 마스크의 수요가 급증하고 이에 따라 마스크의 가격이 폭등하자 정부가 건강보험정보를 기반으로 보건용 마스크 판매에 관여하는 공적 마스크 5부제를 시행해 왔다. 하지만 건강보험 가입정보에 의존적인 신원 인증 시스템으로 인해 유학생 등 건강보험 미가입자의 경우 마스크의 구입이 어렵고 개인정보 접근 문제 등으로 판매채널의 확장이 어려운 문제가 있었다. 본 논문에서는 건강보험과 같은 특정 신원정보 시스템에 의존하지 않고 중앙기관이 발행하는 신뢰할 수 있는 모든 신원정보(여권, 외국인등록증 등)에 기반하여 사용자가 스스로 자신의 신원정보 속성을 블록체인을 통해 관리하는 방법을 제안한다. 또한 제안 방법에 대해 디지털신원 기법을 평가할 수 있는 지표를 기반으로 자체 평가를 수행한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2020.05a
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• pp.231-234
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• 2020

In the past few years, the industrial internet of things (IIoT) has received great attention in various industrial sectors which have potentially increased a high level of integrity, availability, and scalability. The increasing of IIoT is expected to create new smart industrial enterprises and build the next generation smart system. However existing IIoT systems rely on centralized servers that are vulnerable to a single point of failure and malicious attack, which exposes the data to security risks and storage. To address the above issues, blockchain is widely considered as a promising solution, which can build a secure and efficient environment for data storing, processing and sharing in IIoT. In this paper, we propose a decentralized, peer-to-peer platform for secure data storing in industrial IoT base on the ethereum blockchain. We exploit ethereum to ensure data security and reliability when smart devices store the data.

• Advances in Energy Research
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• v.8 no.1
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• pp.1-19
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• 2022

The application of Photovoltaic (PV) power in the building sector, is expanding as part of the ongoing energy transition into renewables. The article addresses the question of sustainability of energy generated from PVs through an environmental assessment of a building-integrated PV system (BIPV) connected to the grid through net metering. Employing retrospective life cycle analysis (LCA), with the CCaLC2 software and ecoinvent data, the article shows that the carrying structure and other balance of system (BOS) components are responsible for a three times higher energy payback time than the literature average. However, total environmental impact can be lowered through reuse or reinstallation of PVs on the same building structure after the 30-year interval. Further ways to improve environmental efficiency include identifying the most polluting materials for each LCA parameter. The results of this study are of interest to researchers and producers of PVs and organizations investing and promoting decentralized power production through PVs.