• Proceedings of the Korean Operations and Management Science Society Conference
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• 2005.10a
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• pp.27-37
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• 2005

The rectilinear Steiner tree problem (RSTP) is to find a minimum-length rectilinear interconnection of a set of terminals in the plane. It is well known that the solution to this problem will be the minimal spanning tree (MST) on some set Steiner points. The RSTP is known to be NP-complete. The RSTP has received a lot of attention in the literature and heuristic and optimal algorithms have been proposed, A key performance measure of the algorithm for the RSTP is the reduction rate that is achieved by the difference between the objective value of the RSTP and that of the MST without Steiner points. A hybrid evolution strategy on RSTP based upon the Prim algorithm was presented. The computational results show that the evolution strategy is better than the previously proposed other heuristic. The average reduction rate of solutions from the evolution strategy is about 11%, which is almost similar to that of optimal solutions.

• Korean Management Science Review
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• v.23 no.1
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• pp.75-85
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• 2006

The rectilinear Steiner tree problem (RSTP) is to find a minimum-length rectilinear interconnection of a set of terminals in the plane. It is well known that the solution to this problem will be the minimal spanning tree(MST) on some set Steiner points. The RSTP is known to be NP-complete. The RSTP has received a lot of attention in the literature and heuristic and optimal algorithms have been proposed. A key performance measure of the algorithm for the RSTP is the reduction rate that is achieved by the difference between the objective value of the RSTP and that of the MST without Steiner points. A hybrid evolutionary strategy on RSTP based upon nodes set is presented. The computational results show that the hybrid evolutionary strategy is better than the previously proposed other heuristic. The average reduction rate of solutions from the evolutionary strategy is about 11.14%, which is almost similar to that of optimal solutions.

• KEPCO Journal on Electric Power and Energy
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• v.6 no.3
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• pp.259-269
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• 2020

With the proposal-agreement procedure, RSTP can reduce the network recovery time to 400 ms or less in the case of 40 bridges. While the legacy RSTP reverts the previous agreement at the bridge with the alternate port role in the ring during the fault recovery, a new position based fast fault recovery procedure is proposed in this paper to guarantee a single proposal-agreement transaction which can provide more faster recovery. By knowing the relative position of the faulty link or bridge in hops, the bridge on the middle of the ring can complete the recovery procedure without revert. The performance of proposed procedure is numerically calculated and verified by simulation and the result shows that the recovery time can be reduced up to 100 ms, which is 1/4 times of the legacy RSTP.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.6
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• pp.744-749
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• 2013

The protection switching technology is widely adopted in the fiber-optical transmission equipments based on TDM(Time Division Multiplexing), such as PDH, SDH/SONET. A variety of protection switching algorithms for Ethernet networks and the progress of standardization are summarized in the document. There are several kinds of protection switching algorithms for Ethernet networks, such as STP, RSTP, MSTP and etc. However, since Ethernet signal move through detour route, it causes much time to recover. Accordingly, it is difficult to secure a usability of Ethernet networks and QOS(Quality of Service). Also, if the protection switching protocol standardized by IEEE and ITU-T is used, it remains a inherent network switching time for protection. Therefore, a specific protection switching algorithm for Ethernet are needed for seamless and stable operation of Ethernet networks service for Distribution Automation System(DAS). A reliable protection algorithm with no switching delay time is very important to implement Self-healing service for DAS. This study of FPGA based protection switching algorithm for Ethernet networks shows that in case of faults occurrence on distribution power network, immediate fault isolation and restoration are conducted through interaction with distribution equipments using P2P(Peer to Peer) communication for protection coordination. It is concluded that FPGA based protection switching algorithm for Ethernet networks available 0ms switching time is crucial technology to secure reliability of DAS.

• Proceedings of the Korea Information Processing Society Conference
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• 2018.10a
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• pp.136-138
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• 2018

최근 네트워크 서비스의 발달과 카메라 장치의 소형화에 따라 다양한 스트리밍 서비스들이 각광을 받고 있다. 특히, 특정구역을 모니터링 하는 CCTV 서비스의 경우 다양한 사용자의 요구사항을 만족시키기 위해 오픈소스 CCTV 플랫폼들이 개발되고 있다. 본 논문에서는 네트워크 카메라를 사용하는 사용자 맞춤형 CCTV 서비스를 제공하기 위한 도커 컨테이너 가반 CCTV 서비스 관리 프레임워크 설계 및 구현에 대한 내용을 기술한다. 제안하는 프레임워크는 다양한 사용자 요구를 충족시킬 수 있도록 오픈소스 CCTV 플랫폼들을 도커 컨테이너 기반으로 관리하는 서버를 포함하고, 해당 관리 서버에 접근하기 위한 Restful API를 제공한다. 또한, 네트워크 카메라는 RSTP 기반의 스트리밍 데이터를 오픈소스 CCTV 플랫폼에 제공함으로써 스트리밍 서비스의 확장성을 확보할 수 있다.

• The Journal of the Korea institute of electronic communication sciences
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• v.16 no.1
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• pp.101-108
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• 2021

This paper builds a real-time home security system based on the OneNet cloud platform to control the status of the house through a smartphone. The system consists of a local part and a cloud part. The local part has I/O devices, router and Raspberry Pi (RPi) that collects and monitors sensor data and sends the data to the cloud, and the Flask web server is implemented on a Rasberry Pi. When a user is at home, the user can access the Flask web server to obtain the data directly. The cloud part is OneNet in China Mobile, which provides remote access service. The hybrid App is designed to provide the interaction between users and the home security system in the smartphone, and the EDP and RTSP protocol is implemented to transmit data and video stream. Experimental results show that users can receive sensor data and warning text message through the smartphone and monitor, and control home status through OneNet cloud.