• 한국건설관리학회:학술대회논문집
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• 한국건설관리학회 2006년도 정기학술발표대회 논문집
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• pp.373-377
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• 2006

90년대 초 한국의 건설 경기가 호황을 누리면서 건설현장을 관리할 수 있는 특급기술자에 대한 수요가 커졌었다. 이러한 특급기술자의 수요를 맞추기 위해 정부는 1995년에 기술사시험에 의하지 않고 단지 경력년 수만으로 특급기술자 자격을 부여하는 인정경력자제도를 만들었다. 그러나 2000년 이후 특급기술자의 부족현상은 해소되었고, 그 반대로 특급기술자의 심각한 과잉공급이 초래되었다. 따라서, 정부는 인정경력자제도를 폐지(기존의 인정경력자를 인정)한다고 발표하였다. 그러나 기술인협회에서는 기존의 인정기술자까지도 인정하지 말아야 한다며 대립 주장을 펴고 있다. 본 연구에서는 이러한 대립관점에서 시스템 다이내믹스 방법론을 이용한 수요공급 예측 모델은 정부와 기술인협회사이의 대립주장을 해결할 수 있는 실마리를 제공할 것이다. 본 논문은 각 시나리오를 통해 인정기술사제도의 변화에 따른 특급기술자의 공급변화를 보여주며, 정책입안자가 특급기술자의 수요와 공급의 균형을 위한 제안점을 시사하고 있다.

• 한국컴퓨터정보학회논문지
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• 제8권3호
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• pp.179-187
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• 2003

이 논문에서는 정보보안 분야의 각종의 위험신호(risk signal)에 대해 조직이 왜 적절한 대응을 하지 못하는 가를 조직의 구조적 측면에서 그 원인을 분석하고자 하였다. 위기는 갑자기 오지 않으며, 많은 경우 위기는 위기와 관련한 위험신호(risk signal)를 제기하면서 진전된다. 이러한 위험신호에 대해 적절하게 대응하는 경우, 위험은 새로운 기회를 만들어내게 되지만 그러하지 않은 경우 위험은 경제적, 비경제적인 측면에서 재난적인 결과를 초래할 가능성을 갖는다. 이 논문에서는 인과지도(causal diagram)을 이용하여 시스템적인 관점에서 환류하는 인과 고리의 관점에서 현상을 분석하는 시스템 다이나믹스적인 분석을 시도하였다. 분석결과, 조직의 성장과 업적 위주의 분위기가 일종의 압력이 되어, 안전에 대한 불감을 강화하게 되며, 이는 각종의 위험신호들에 내재된 위험성에 대해 과소평가하는 압력으로 작용하게 되는 점을 분석하였다. 이는 나아가서 기술적 기반에 대해 적절한 투자가 이루어지 못하게 하고, 정보보안과 관련한 학습을 적절하게 하지 못하도록 한 것으로 나타난다. 이 논문은 탐색적으로 정보보안 분야에서의 위험신호와 조직학습과의 관계를 분석한 탐색적 연구로서의 성격을 가진다.

• 융합신호처리학회논문지
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• 제2권1호
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• pp.95-100
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• 2001

본 논문에서는 불확실성을 갖는 비선형 시스템에 제어기를 설계하기 위해서 출력제환 선형화 방법을 통하여 비선형 시스템을 선형시스템으로 변환하고 슬라이딩 모드 제어기법을 사용하여 파라미터들을 갱신하고 이를 통하여 제어입력을 갱신하는 강인성제어기를 제안하고자 한다. 비선형시스템은 최소 위상시스템이고, 시스템의 상대차수는 r＜n 이며, 제로 다이나믹스는 안정하다고 가정한다. 제안된 제어기에 대해서 대역적 점근적 안정도가 보장됨을 보였으며, 제안된 제어기에 대해서 컴퓨터 시뮬레이션을 통하여 타당성을 검증하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 F
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• pp.2490-2492
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• 1999

본 논문에서는 벡터 제어 유도전동기 구동 시스템에서 과변조시 출력 토오크 향상을 위한 새로운 과변조 기법을 제안한다. 제안된 과변조 기법은 인버터의 전압 제한과 유도 전동기의 전류 다이나믹스를 동시에 고려하여, 과변조시 동기좌표계 d축 전압을 감소시킴으로써 순시적으로 d축 전류를 감소시키고 q축 전류 제어를 위한 전압 여유를 확보한다. 따라서 과변조시에도 q축 전류 제어가 원활하게 수행됨에 따라 전동기의 출력 토오크를 향상시킨다. 기존의 기법과의 비교 실험에서 제안된 기법이 우수함을 증명하였다.

• 한국산업정보학회:학술대회논문집
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• 한국산업정보학회 1999년도 춘계학술대회 발표논문집
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• pp.36-44
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• 1999

임금이란 사용자의 입장에서는 비용으로, 근로자의 입장에서는 생활의 원천이 되는 소득으로 자본주의 경제에 있어서 기업측과 근로자측은 임금을 둘러싸고 상반된 이해관계에 놓이게 된다. 그러한 사정은 노사갈등의 직접적인 원인이 될 수 있으므로 근로자의 욕구를 충족시키면서 기업의 이익을 보장할 수 있는 합리적인 임금관리가 요청된다. 본 논문에서는 임금과 관련된 주요 변수들을 시스템 다이나믹스 개념 측면에서 분석하여 문제발생의 원인과 해결방법을 모색하고 이를 단순화된 상황속에서 가상 시뮬레이션을 해 봄으로써 이상적인 임금체계 설계의 방향을 제시 해보았다.

• 한국정보시스템학회지:정보시스템연구
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• 제20권3호
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• pp.25-40
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• 2011

Small and Medium sized hospitals are exposed to severe managerial environments recently. Around 8.0% of the hospitals are bankrupted every year. The adverse managerial environment does not only come from external factors such as patients' preference for larger hospitals, regulations on the medical charges; more serious problems come from the way the medium and small sized hospitals deal with those exogenous changes including lack of management skills, lack of change management skills, lack of managerial decision support systems, etc. This paper aims to support managers to make decisions regarding the exogenous changes. This paper can be interpreted as an attempt of a merge of the two techniques; BSC and system dynamics. Starting with a BSC system, the development of a system dynamics model can take advantages of the BSC information.

• Tribology and Lubricants
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• 제37권3호
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• pp.91-98
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• 2021

This paper presents a hydrostatic bearing design and rotordynamic analysis of a turbo expander for a hydrogen liquefaction plant. Th~e turbo expander includes the turbine and compressor wheel assembled to a shaft supported by two hydrostatic radial and thrust bearings. The rated speed is 75,000 rpm and the rated power is 6 kW. For the bearing operation, we use pressurized air at 8.5 bar as the lubricant that is supplied to the bearing through the orifice restrictor. We calculate the bearing stiffness and flow rate for various gauge pressure ratios and select the orifice diameter providing the maximum bearing stiffness. Additionally, we conduct a rotordynamic analysis based on the calculated bearing stiffness and damping considering design parameters of the turbo expander. The predicted Cambell diagram indicates that there are two critical speeds under the rated speed and there exists a sufficient separation margin for the rated speed. In addition, the predicted rotor vibration is under 1 ㎛ at the rated speed. We conduct the operating test of the turbo expander in the test rig. For the operation, we supply pressurized air to the turbine and monitor the shaft vibration during the test. The test results show that there are two critical speeds under the rated speed, and the shaft vibration is controlled under 2.5 ㎛.

• 국내 학술지 테스트 저널
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• 제11권2호
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• pp.221-227
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• 2023

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• 산업경영시스템학회지
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• 제29권3호
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• pp.25-32
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• 2006

자동차 개발 단계는, 본질적으로, 수차례의 개발 단계를 거치면서 설계 그룹들 간의 정보 전달과 교환이 여러 차례 반복적으로 발생하게 된다. 이러한 복잡한 상호 정보 교환 과정을 정확하게 이해하여 업무가 수행되지 못하면 불필요한 재작업을 야기시킬 수 있으며, 이는 비용 낭비 및 계획에 차질이 발생할 수 있다. 이 연구에서는 시스템 다이나믹 모델을 개발하여 빈번한 design-built-test 싸이클이 자동차 개발 단계에 미치는 영향 및 이점들을 고찰하였다.

• 한국시뮬레이션학회:학술대회논문집
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• 한국시뮬레이션학회 2003년도 추계학술대회 및 정기총회
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• pp.193-200
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• 2003

급변하는 시장환경에서 고객수요가 불확실한 상황에서 고객서비스를 최우선으로 하는 기업에서는 전략적인 제휴를 통해 기업의 경쟁력을 확보하는 것이 최우선이라고 하겠다. 이러한 환경에서 대두된 경영혁신 기법들이 공급체인관리와 아웃소싱 개념이라고 할 수 있는데, 이에 본 연구에서는 제조기업의 입장에서 제품가격 경쟁력을 확보하기 위한 일환으로 재고량을 줄이고, 판매량을 늘리는 방안을 제고하고자 한다. 비용과 서비스 관점에서 볼 때 이들은 서로 상충관계에 있지만, 본 연구에서 제안하는 재고 공유 시스템을 통한 공동 재고정책은 기업의 입장에서 볼 때, 보다 적은 재고를 보유함으로써, 재고유지비용을 절감하고, 이는 최종 제품가격의 하락으로 이어져 가격효과를 통한 매출량의 증대시킬 수 있게 된다. 이를 검증하기 위해 본 연구에서는 시스템 다이나믹스 방법을 이용하고, 이를 통하여 본 연구에서 제시된 재고 공유 시스템구축의 타당성을 검증하고, 분석하였다