• Journal of Korea Society of Industrial Information Systems
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• v.11 no.1
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• pp.21-28
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• 2006

This paper describes the design and implementation of video conference system using hybrid type P2P(Peer to Peer). The proposed video conference system has hybrid type P2P architecture based on a client-server and P2P(Peer to Peer), where client-server is used for exchange of account management, client list and status information and P2P is used for the real time video conference. The proposed video conference system decreases the traffic of server, and cuts down the load of a network. Because the multimedia data is decentralized to client by P2P. Also, this system is tested by the multi-party video conference system using communication protocol and application software through high speed networks.

• Environmental Engineering Research
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• v.25 no.3
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• pp.267-273
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• 2020

This Hydrokinetic energy system is the process of extracting energy from rivers, canals and others sources to generate small scale electrical energy for decentralized usage. This study investigates the application of Soil and Water Assessment Tool (SWAT) in Geographical Information System (GIS) environment to evaluate the theoretical hydrokinetic energy potentials of selected Rivers (Asa, Awun and Oyun) all in Asa watershed, Kwara state, Nigeria. SWAT was interfaced with an open source GIS system to predict the flow and other hydrological parameters of the sub-basins. The model was calibrated and validated using observed stream flow data. Calibrated flow results were used in conjunction with other parameters to compute the theoretical hydrokinetic energy potentials of the Rivers. Results showed a good correlation between the observed flow and the simulated flow, indicated by ash Sutcliffe Efficiency (NSE) and R² of 0.76 and 0.85, respectively for calibration period, and NSE and R² of 0.70 and 0.74, respectively for the validation period. Also, it was observed that highest potential of 154.82 MW was obtained along River Awun while the lowest potential of 41.63 MW was obtained along River Asa. The energy potentials obtained could be harnessed and deployed to the communities around the watershed for their energy needs.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.50 no.9
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• pp.431-439
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• 2001

This Paper illustrates a new numerical analysis method using a nodal effective load model for nodal probabilistic production cost simulation of the load point in a composite power system. The new effective load model includes capacities and uncertainties of generators as well as transmission lines. The CMELDC(composite power system effective load duration curve) based on the new effective load model at HLll(Hierarchical Level H) has been developed also. The CMELDC can be obtained from convolution integral processing of the outage capacity probabilistic distribution function of the fictitious generator and the original load duration curve given at the load point. It is expected that the new model for the CMELDC proposed in this study will provide some solutions to many problems based on nodal and decentralized operation and control of an electric power systems under competition environment in future. The CMELDC based on the new model at HLll will extend the application areas of nodal probabilistic production cost simulation, outage cost assessment and reliability evaluation etc. at load points. The characteristics and effectiveness of this new model are illustrated by a case study of MRBTS(Modified Roy Billinton Test System).

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.13 no.4
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• pp.298-305
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• 2020

This paper deals with the implementation of electronic voting system using permissioned block chain technology. Cases studies have recently been under way in many industrial areas to review the application of the blockchain based electronic voting system. The existing electronic voting system was easily exposed by hacking because of its centralized characteristics, making it difficult to ensure the reliability and transparency of the voting system itself. In this study, we proposed key considerations and concepts to ensure the reliability and transparency of voters and voting stakeholder by utilizing a hyperledger fabric which is nowadays widely used as a permissioned blockchain.

• Current Optics and Photonics
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• v.6 no.5
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• pp.453-462
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• 2022

Blockchain technology provides a decentralized and peer-to-peer network, which has the advantages of transparency and immutability. In this paper, a novel secure authentication scheme applying digital holography to blockchain technology is proposed to protect privacy information in network nodes. The transactional information of the node is chained permanently and immutably in the blockchain to ensure network security. By designing a novel two-dimensional (2D) array data structure of the block, a proof of work (PoW) in the blockchain is executed through digital holography technology to verify true authentication and legal block linkage. A hash generated from the proposed algorithm reveals a random number of 2D array data. The real identity of each node in the network cannot be forged by a hacker's tampering because the privacy information of the node is encrypted using digital holography and stored in the blockchain. The reliability and feasibility of the proposed scheme are analyzed with the help of the research results, which evaluate the effectiveness of the proposed method. Forgery by a malicious node is impossible with the proposed method by rejecting a tampered transaction. The principal application is a secure anonymity system guaranteeing privacy information protection for handling of large information.

• Proceedings of the Korea Information Processing Society Conference
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• 2022.11a
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• pp.216-218
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• 2022

최근 공인인증서가 폐지되고 보다 발급이 간편하고 유효기간이 긴 사설인증서가 부상했다. 더불어 탈중앙화를 핵심 개념으로 하는 블록체인 기반 분산 신원 증명(Decentralized Identity, DID)기술이 대두되고 있다. 서비스 환경의 변화에 따라 사용자 인증 기술도 변화가 요구된다. 더욱이 메타버스라는 새로운 인터넷 환경이 조성되고 있는 바 현재 사용자 인증 기술의 동향을 살펴보고 미래에 사용자 인증이 나아갈 방향성을 제시하는 것은 의미가 있어 보인다. 본 논문에서는 사용자 인증 기술의 개요와 사용자 인증 기술의 변천과정을 시작으로 공개키 기반 구조(Public Key Infrastructure, PKI)와 분산 신원 증명을 중심으로 시장에서의 사용자 인증 기술의 동향을 살펴본다. 나아가 메타버스가 상용화되었을 시기에 사용자 인증 기술이 나아가야할 세가지 방향성(분산화, 플랫폼 초월, 생체 기반 인증 중심)을 제시한다.

• Journal of the Korean Institute of Landscape Architecture
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• v.43 no.3
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• pp.13-26
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• 2015

Many urban areas in Korea suffer from repeated flood damage during intensive rainfall due to an increase in impervious areas caused by rapid urbanization and deteriorating sewage systems. A centralized stormwater management system has caused severe flood damage in an area that has proven unable to accommodate recent climate change and a rise in precipitation. Most flooding prevention projects that have been recently implemented focus on increasing drainage system capacity by expanding the size of sewer pipes and adding pumping stations in downstream areas. However, such measures fail to provide sustainable solutions since they cannot solve fundamental problems to reduce surface runoff caused by urbanization across the watershed. A decentralized stormwater management system is needed that can minimize surface runoff and maximize localized retention capacity, while maintaining the existing drainage systems. This study proposes a stormwater management corridor for the flood-prone watershed in the city of Dongducheon. The corridor would connect the upstream, midstream, and downstream zones using various methods for reducing stormwater runoff. The research analyzed surface runoff patterns generated across the watershed using the Modified Rational Method considering the natural topography, land cover, and soil characteristics of each sub-watershed, as well as the urban fabric and land use. The expected effects of the design were verified by the retainable volume of stormwater runoff as based on the design application. The results suggest that an open space network serve as an urban green infrastructure, potentially expanding the functional and scenic values of the landscape. This method is more sustainable and effective than an engineering-based one, and can be applied to sustainable planning and management in flood-prone urban areas.

• Journal of Korean Society of Transportation
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• v.22 no.7 s.78
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• pp.91-98
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• 2004

This study focuses on the development of dynamic assignment for evaluation and application for dynamic route guidance strategy. Travelers are classified according to information contents which they received pre/on trip. The first group have no traffic information, so they travel with fixed route. The second group have real-time shortest path and travel according to it. The last group have car navigation system or individual method(cellular phone, PDA-two way communication available) for traffic information on trip. And then they are assigned in accordance with the proposed multiclass dynamic assignment model. At this time the last group is gotten under control with DFS(decentralized feedback strategy). In use of this Process we expect that various traffic information strategy can be tested and also be the key factor for success of ITS, location of VMS(variable message sign), cycle of information, area of traffic information, etc).

• The Journal of Society for e-Business Studies
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• v.23 no.3
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• pp.13-32
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• 2018

Btcoin has made a big progress through anonymity, decentralized authority, sharing economy, multi-ledger book-keeping, block-technology and the convenient financial vehicle. Bitcoin has the characteristics of mining and supply by decentralized suppliers, limited supply quantity and the partial money-like function as well as gold. The paper studies the hedge and safe-haven of Bitcoin and gold on daily frequency data over the period of July 20, 2010-Dec. 27, 2017 employing Asymmetric Vector GARCH. It finds that gold has the hedge and safe-haven against inflation and capital markets while Bitcoin has the weak hedge and the weak safe-haven. It shows insignificant effects of inflations of US and Korea on the volatilities of Bitcoin and gold. It also suggests the necessity of clearing of vagueness behind the anonymity for fair and transparent trade through the law application in the absence or fault in law (Lucken im Recht). following the spirit of the living constitution (lebendige gutes Recht oder Vorschrift). The relevant institutions are hoped to be given some of obligations such as registration, minimum required capital. report, disclosure, explanation, compliance and governance with autonomous corresponding rights. The study also suggests the reestablishment of the relevant financial law and taxation law. The hedge would not be successfully accomplished without the vigilant cautions of investors.

• Knowledge Management Research
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• v.23 no.3
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• pp.23-44
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• 2022

With the development of blockchain technology, play-to-earn (P2E) games, one of the decentralized applications (dApps), are receiving great social attention. P2E games are positively evaluated as areas with high growth potential based on blockchain technology, and at the same time, they are negatively evaluated as speculative as people can cash P2E game items in the form of cryptocurrency. In this situation, the purpose of this study is to investigate factors affecting the intention to use P2E games. Along with the discussion of hedonic system adoption, we consider the factors with perceived enjoyment, economic incentive, and social influence. In order to verify our research model, data were collected from 350 adults with P2E game experience or recognition, and a structural equation model was carried out. The analysis results find that perceived enjoyment and subjective norm have a significant positive effect on the intention to use P2E games, and economic incentive does not have a significant effect. In addition, peer influence and external influence have a significant positive effect on subjective norm. Drawing on these findings, we present several academic and practical implications for future research.