• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 C
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• pp.926-928
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• 1998

A fast optimization algorithm has been evolved from a simple two stage optimal power flow(OPF) algorithm for constrained power economic dispatch. In the proposed algorithm, we consider various constraints such as power balance, generation capacity, transmission line capacity, transmission losses, security equality, and security inequality constraints. The proposed algorithm consists of four stages. At the first stage, we solve the aggregated problem that is the crude classical economic dispatch problem without considering transmission losses. An initial solution is obtained by the aggregation concept in which the solution satisfies the power balance equations and generation capacity constraints. Then, after load flow analysis, the transmission losses of an initial generation setting are matched by the slack bus generator that produces power with the cheapest cost. At the second stage we consider transmission losses. Formulation of the second stage becomes classical economic dispatch problem involving the transmission losses, which are distributed to all generators. Once a feasible solution is obtained from the second stage, transmission capacity and other violations are checked and corrected locally and quickly at the third stage. The fourth stage fine tunes the solution of the third stage to reach a real minimum. The proposed approach speeds up the coupled LP based OPF method to an average gain of 53.13 for IEEE 30, 57, and 118 bus systems and EPRI Scenario systems A through D testings.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2011년도 추계학술대회
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• pp.353-356
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• 2011

전파를 수집하고 분석하는 신호수신시스템은 실 운용환경에서 검증되기 전에 정밀한 모의전파신호원을 이용한 정량적인 성능예측 및 실 환경과 유사한 모의전파환경에서 검증되어야한다. 신호수신 시스템은 전파의 주파수(Frequency), 펄스 변조(Pulse Modulation), 스캔 변조(Scan Modulation), 펄스 내 위상변조(Phase Modulation On Pulse), 펄스 내 주파수 변조(Frequency Modulation On Pulse) 등 다양한 신호특성에 대한 측정, 분석능력을 갖는다. 이러한 신호원들은 기본으로 실험실 환경에서 모의발생 되어야 하고 전파가 다수 존재하는 복잡한 전파환경 또한 모의되어야 한다. 본 논문에서는 효과적인 전파신호원의 모의발생, 운용시나리오에 따른 정밀고주파시험신호 모의방법에 관한 연구 결과를 서술한다.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2004년도 춘계종합학술대회
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• pp.709-712
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• 2004

BcN 네트워크 환경은 정통부의 지원 아래 2007년까지 단계적으로 공중망, 지역망 및 대부분의 단말에 도입될 예정이다. BcN 환경의 인프라인 IPv6 도입과 함께 현재의 네트워크 보안 구조도 Ipv6 트래픽 및 네트워크 환경을 고려한 차세대 네트워크 구조로 진화해야만 한다. 차세대 네트워크 보안 구조는 Ipv6 적용과 함께 네트워크의 또 다른 흐름인 유무선 통합에 대한 고려도 필요하다. 따라서, 본 논문에서는 향후 Ipv6가 적용되고 유무선이 통합될 네트워크 환경을 고려한 차세대 네트워크 보안 요구사항을 분석하고 차세대 네트워크 보안 구조를 제안한다.

• 신재생에너지
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• 제18권2호
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• pp.50-59
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• 2022

The Korean government announced the "1st Basic Plan for the Transition to Hydrogen Economy" in 2021 and declared the establishment of a hydrogen industry ecosystem by 2040. To build a low-carbon power system, resources that can efficiently accommodate renewable energy are required, and green hydrogen is considered a potential solution. This study analyzed the economic feasibility of green hydrogen-based sector coupling to reduce curtailment of renewable generation in the Jeju power system by 2025 under the scenario of with or without HVDC#3. The result showed that HVDC#3 significantly reduced the frequency of curtailment from 16.1% to 3.0%. In addition, green hydrogen-based sector coupling was an economically feasible option as result showed an IRR of 4.86% when HVDC#3 was connected and 11.45% when it was not under the condition of achieving 50% curtailment reduction. This study shows that the higher the level of renewable energy deployment, the more delayed the HVDC connection between Jeju and the main land, and the lower the SMP, the more economically feasible the green hydrogen-based sector coupling is. Furthermore, this study suggests that the policy goal of completely reducing curtailment is not economically efficient.

• 디지털융복합연구
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• 제10권1호
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• pp.349-355
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• 2012

오늘날 복잡해져가는 컴퓨팅 환경에서 자가치유를 위해 시스템에 발생한 문제를 스스로 인식하는 능력을 부여하는 연구가 중요한 이슈가 되고 있다. 그러나, 기존 방법론들은 새로운 요구사항에 대한 목표 시스템을 자가 치유하기 위해 개발자들이 제약조건을 모델링하고 분석해야 하는 노력이 크다. 따라서, 본 논문에서는 시스템에서 발생한 문제를 인식하고 감지된 문제를 해결하기 위해 목표 시나리오 기반의 분석하고, 전 후 전략을 적용하여 동적으로 재구성되도록 자가 치유 방법을 제시하도록 한다. 이러한 제안 방법론을 통해 새로운 요구사항에 대한 자가 치유 개발자의 분석의 부하를 줄이고, 변경 정보를 파악하여 동적으로 재구성 되도록 지원하도록 한다.

• 전기학회논문지
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• 제67권2호
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• pp.173-178
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• 2018

This study organizes scenarios on the power supply and demand plans considering the uncertainties and the portion of distributed energy resources. In analysing the scenarios, it estimates total electricity supply cost in the social aspect, natural gas demand and air pollutants emission including carbon dioxide. Also the analysis is performed to estimate the marginal cost of carbon dioxide reduction for the fuel switching from coal to liquified natural gas. In result, the social cost could be decreased by replacing some portion of renewable energy by LNG-based combined heat and power and delaying the construction of large base-load generators such as coal and nuclear plants. The marginal carbon dioxide reduction cost by fuel switching is in plausible range for fuel switching to be an option for carbon dioxide emission reduction when the social cost is considered.

• Journal of information and communication convergence engineering
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• 제7권2호
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• pp.135-140
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• 2009

The wide deployment of wireless access technologies and the integration of various access network interfaces into a single terminal, allows mobile end-users to be always connected to the IP network, and to use those interface simultaneously. In this paper the CTE provides various access network interfaces capabilities, allowing reception of data over multiple service providers with different characteristics. Considerations for multiple network and service provider environments are regarded as essential for the successful deployment of convergence services in Next Generation Network (NGN). Event Driven Service (EDS) is regarded as a typical convergence service converging different functions of multiple service providers. This paper first describes the deployment model of NGN convergence services for multiple service provider environments. It also covers the service scenario of EDS, a convergence service for multiple service provider environments in NGN. Multiple provider environments stimulates the unified identifier management, namely ubiquitous identification (U-ID), to enable users to be provided convergence services without awareness of multiple provides. Then the designed structure and procedures of U-ID based EDS are given. Finally, the implementation results tested on Korea Advanced Research Network (KOREN) are described.

• Nuclear Engineering and Technology
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• 제55권11호
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• pp.4181-4190
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• 2023

Nuclear power plants are subjected to various processes during decommissioning, including cutting, decontamination, disposal, and treatment. The cutting of massive bio-shields is a significant step in the decommissioning process. Cutting is performed near the target structure, and during this process, workers are exposed to potential radioactive elements. However, studies considering worker exposure management during such cutting operations are limited. Furthermore, dismantling a nuclear power plant under certain circumstances may result in the unnecessary radiation exposure of workers and an increase in secondary waste generation. In this study, a cutting scenario was formulated considering the bio-shield as a representative structure. The specifications of a standard South Korean radioactive waste disposal drum were used as the basic conditions. Additionally, we explored the hot-to-cold and cold-to-hot methods, with and without the application of polishing during decontamination. For evaluating various scenarios, different cutting time points up to 30 years after permanent shutdown were considered, and cutting speeds of 1-10nullm²/h were applied to account for the variability and uncertainty attributable to the design output and specifications. The obtained results provide fundamental guidelines for establishing cutting methods suitable for large structures.

• 경영정보학연구
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• 제10권2호
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• pp.21-48
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• 2008

본 연구는 온라인 게임 산업의 구조적인 변화와 IPTV 환경변화에 초점을 두고 IPTV 도입에 따른 게임 산업의 변화를 시나리오 플래닝을 통해 제시해 보았다. 분석의 절차는 IPTV 도입과 관련하여 온라인 게임 산업에서 제기 되고 있는 핵심이슈들을 선별하고 각 이슈 별로 주요 추세와 불확실성요인들을 분석하여 IPTV 도입에 따른 온라인 게임 산업의 변화 양상을 논리적인 시나리오들로 제시하였다. 그리고 미래 발생 가능한 시나리오에 따른 온라인 게임 업체들의 전략적 대응 방안의 방향성을 제시하였다. 시나리오 수립에 앞서 온라인 게임 산업의 디지털 콘텐츠로써 고유한 특성과 IPTV 환경변화에 따른 산업 구조적인 변화를 반영하기 위해 디지털 콘텐츠 가치사슬 분석을 실시하였다. 분석을 통해 시나리오의 핵심이슈를 도출하고 각각에 영향을 미치는 영향요인들을 도출하였으며, 영향력과 불확실성 정도에 따라 이들 영향요인을 각각 주요추세와 불확실성 요인으로 분류할 수 있었다. 이중 불확실성이 크고 영향력이 높은 요인들을 핵심문제로 정의하였다. 이들 분석 결과를 바탕으로 형태학적 분석기법을 통해 시나리오를 수립하였다. 수립된 시나리오를 바탕으로 최종적으로 IPTV 도입에 따른 온라인 게임 환경 변화 상황에서 기업이 선택 가능한 전략적 대안의 방향을 제시하였다.

• Radiation Oncology Journal
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• 제37권2호
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• pp.134-142
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• 2019

Purpose: The aim is to study the dependence of deformable based auto-segmentation of head and neck organs-at-risks (OAR) on anatomy matching for a single atlas based system and generate an acceptable set of contours. Methods: A sample of ten patients in neutral neck position and three atlas sets consisting of ten patients each in different head and neck positions were utilized to generate three scenarios representing poor, average and perfect anatomy matching respectively and auto-segmentation was carried out for each scenario. Brainstem, larynx, mandible, cervical oesophagus, oral cavity, pharyngeal muscles, parotids, spinal cord, and trachea were the structures selected for the study. Automatic and oncologist reference contours were compared using the dice similarity index (DSI), Hausdroff distance and variation in the centre of mass (COM). Results: The mean DSI scores for brainstem was good irrespective of the anatomy matching scenarios. The scores for mandible, oral cavity, larynx, parotids, spinal cord, and trachea were unacceptable with poor matching but improved with enhanced bony matching whereas cervical oesophagus and pharyngeal muscles had less than acceptable scores for even perfect matching scenario. HD value and variation in COM decreased with better matching for all the structures. Conclusion: Improved anatomy matching resulted in better segmentation. At least a similar setup can help generate an acceptable set of automatic contours in systems employing single atlas method. Automatic contours from average matching scenario were acceptable for most structures. Importance should be given to head and neck position during atlas generation for a single atlas based system.