• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 추계학술대회 논문집 Vol.18
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• pp.167-168
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• 2005

The operational characteristics of the integrated three-phase flux-lock type superconducting fault current limiter (SFCL) were analyzed. The suggested three-phase SFCL consisted of a three-phase flux-lock reactor and three high-Tc superconducting (HTSC) elements. The former has three windings wound on an iron core, each of which has the same turn's ratio between coil 1 and coil 2. The latter are connected in series with coil 2 of each phase. The integrated three-phase flux-lock type SFCL showed the operational characteristics that the fault phase could affect the sound phase, which resulted in quenching the HTSC element in the sound phase. Through the computer simulation applying numerical analysis for its three-phase equivalent circuit, the fault current limiting characteristics of the integrated three-phase flux-lock type SFCL according to the ground fault types were compared.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 추계학술대회 논문집 광주전남지부
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• pp.112-113
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• 2006

The operational characteristics of the integrated three-phase flux-lock type superconducting fault current limiter (SFCL) were analyzed. The suggested three-phase SFCL consisted of a three-phase flux-lock reactor and three high-$T_c$ superconducting (HTSC) elements. The former has three windings wound on an iron core, each of which has the same turn's ratio between coil 1 and coil 2. The latter are connected in series with coil 2 of each phase. The integrated three-phase flux-lock type SFCL showed the operational characteristics that the fault phase could affect the sound phase, which resulted in quenching the HTSC element in the sound phase. Through the computer simulation applying numerical analysis for its three-phase equivalent circuit, the fault current limiting characteristics of the integrated three-phase flux-lock type SFCL according to the ground fault types were compared.

• 한국군사과학기술학회지
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• 제15권5호
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• pp.651-659
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• 2012

Target operational availability setting is the first step to setting up a goal which a weapon system development project have to achieve and doing RAM analysis during whole life of a weapon system. It is important as a key factor to doing RAM analysis in the early phase of weapon system development. This paper present a methodology to set a target operational availability for, especially, a warship when it develop. This methodology uses Operational Mode Summary/Mission Profile(OMS/MP) of the developing warship and RAM analysis results of similar warships to calculate wartime and peacetime target operational availability. It will be used in early phase of not only warship development but also army or aircraft weapon systems when these develop.

• 유기물자원화
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• 제19권3호
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• pp.73-78
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• 2011

혐기성 수소 발효시 pH는 물질 대사 경로와 수소 생성 미생물의 활성에 직접적으로 영향을 미치는 가장 중요한 요소 중 하나로 알려져 있다. 본 연구는 음식폐기물로부터 운전 pH에 따른 혐기성 회분식수소 발효의 영향을 평가하기 위해 수행하였다. 5 N KOH 용액을 이용하여 초기 pH는 8.0으로 고정하였으며, 운전 pH는 4.7~7.0으로 유지하였다. 운전 pH가 낮을수록 지체 시간은 단축되는 것으로 나타났으며, 최대 수소 발생량은 낮게 나타났다. 운전 pH 4.7일 경우에는 지체 시간이 47.9 h으로 가장 길게 나타났으나, 최대 수소 발생량은 534.4 mL로 가장 높게 나타났다. 운전 pH가 증가함에 따라 지체 시간과 최대 수소 발생량은 감소하였다. 운전 pH 7.0일 경우에는 지체 시간이 4.2 h으로 나타났으며, 최대 수소 발생량은 213.8 mL로 나타났다.

• Journal of Information Technology Applications and Management
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• 제11권3호
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• pp.35-62
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• 2004

Recently, IT outsouricng has been one of the major concerns of many companies. This paper explores the relationship between information technology outsourcing risk factors and outsourcing performance. It is based upon a three-phase process utilizing IPO (Input-Process-Output) system. The first phase means the outsourcing planning risks t~at arise from overall environment of outsourcing, organizational refuse, and wrong contracts. The second phase implies outsourcing operational risks, which are occurred while out-sourcing perform and consist of organizational acceptances of outsourcing, partnership and hidden costs. The last phase is outsourcing performance based on four perspective of BSC(Blanced Scored Card). The survey was performed on the IT/IS firms, and the data was collected from 53 service receivers. The result of the analysis are as follows. First, Outsourcing planning risks positively affects the operational risks. Second, Outsourcing operational risks negatively affects the Outsourcing Performance.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 하계학술대회 논문집 Vol.9
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• pp.289-289
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• 2008

We investigated the operational characteristics of the separated three-phase flux-lock type superconducting fault current limiter (SFCL). The single-phase lock type SFCL consist of two coils, which are wound in parallel through an iron core. The high-$T_c$ superconducting(HSTC) thin film connected in series with secondary coil. The separated three-phase flux-lock type SFCL consist of three single-phase flux-lock type SFCL. In a normal condition, the SFCL is not operate. When a fault occurs, the current of a HSTC thin film exceeds its critical current by fault current, the resistance of the HSTC thin film generated. Therefore fault current was limited by SFCL. The separated three-phase flux-lock type SFCL are operated in fault condition such as the the single line-to-ground fault, the double line-to-ground fault and the triple line-to-ground fault. The experimental results, the SFCL operational characteristics was dependent on fault condition.

• Journal of applied mathematics & informatics
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• 제42권3호
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• pp.681-693
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• 2024

In this work, we take advantage of Weisnerś group-theoretic and operational identities technique to establish generating functions for the phase-space Hermite polynomials of two-index and two-variables.

• Journal of Information Technology Applications and Management
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• 제13권2호
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• pp.17-28
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• 2006

The SRGM has been studied under the assumption that S/W reliability can grow as the fault causing failure is removed even during operational phase because the debugging is available. On the other hand, some papers insist on the uniform failure rate during operational phase because the debugging may not be available in case of universal software. The phenomenon, however, has been observed informally many times that the products S/W reliability grows as the time goes by even without any debugging in point of customer view. I propose the simple approaching method to model the S/W reliability phenomenon that the failure rate reduces as time goes on without modifying the existing reliability model in this paper.

• 한국산학기술학회논문지
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• 제21권3호
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• pp.269-275
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• 2020

무기체계를 지원하는 요소들 중에 있어서 RAM 업무는 개발 초기단계에 수행되며, 무기체계의 작전요구성능과 함께 설계 관점에서 무기체계가 달성해야 할 기준으로 제시된다. RAM 업무 중 운용가용도는 전투준비태세를 보장하고 전쟁에서 승리하기 위한 군의 핵심요소로서, 무기체계 개발 단계에서 개발기준으로 사용되고 있다. 이러한 운용가용도의 요소에는 평균 고장간 시간, 평균 수리시간, 행정 및 군수 지연시간(ALDT: Administrative and Logistic Delay Time, 이하 ALDT) 등이 있으며, ALDT는 무기체계의 노후화, 정비정책 및 지리적인 특수상항에 달라지는 요소로 군의 전투준비태세를 위해 유지해야 하는 운용가용도의 핵심요소라고 할 수 있다. 개발 간 군은 운용가용도의 요소 중 ALDT, 운용 및 대기 시간 등을 제공하며, 제공시 ALDT가 단순 가정으로 제시되어 개발단계에서 설정되어 산출되는 운용가용도는 실제 운용단계에서 분석한 운용가용도와 상이하다. 따라서, 본 논문에서는 초기 전력화 기간 동안 획득한 고장정비 데이터를 의사결정계보기법을 적용하여 ALDT를 산출하였으며, 본 연구를 통해 전력화 운용기간 동안 개발시 설정한 운용가용도를 달성하기 위한 최적의 ALDT 설정 방안을 제시한다.

• 전기학회논문지
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• 제59권5호
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• pp.882-889
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• 2010

This paper presents a method of finding the optimal operating point minimizing a given objective function with 3 phase power flow equations and operational constraints, called 3 phase optimal power flow (3POPF). 3 phase optimal power flow can provide operation and control strategies for the distribution systems with distributed generation assets, which might be frequently in unbalanced conditions assuming that high penetration rate of renewable energy sources in the systems. As the solution technique for 3POPF, this paper adopts a simulation-based method of particle swarm optimization (PSO). In the PSO based 3POPF, a utility function needs to be defined for evaluation of the degree in operational improvement of each particle's current position. To evaluate the utility function, in this paper, NR-based 3 phase power flow algorithm was developed which can deal with looped distributed generation systems. In this paper, illustrative examples with a 5-bus and a modified IEEE 37-bus test systems are given.