• 대한조선학회논문집
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• 제40권5호
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• pp.1-9
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• 2003

To predict the powering performance of full scale ships from the towing tank tests, resistance, propeller open water and self-propulsion tests are conducted. Model tests inevitably include the experimental error defined as the sum of two types of uncertainties, bias and precision errors. The induced errors in each element of model test are propagated through various routes and correlated with one another. The correlation coefficients are very important in the uncertainty analysis. The coefficient gives a direction(increase or decrease) for a value of error in individual elements. If the coefficient is not used accurately, the error bounds of the individual elements are overestimated or underestimated. In this study, the new methodology is applied to the uncertainty analysis of HMRI's towing tank tests, thus error bounds of each element is suggested and verified by several repetitive experiments.

• 제어로봇시스템학회논문지
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• 제5권6호
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• pp.667-675
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• 1999

In this paper, we propose a robust controller design of RTP(Rapid Thermal Processing) system using structured uncertainty approach. Using the weighted mixed sensitivity function, we solve the robust stability problem against disturbance and temperature variation, and design a $\mu$ controller using curve fitting method against structured uncertainty. Also the reduction method should be requried because of the difficulty of implementaion with the obtained high order controller. We dal with robust stability and performance of RTP system by the design of $\mu$ controller for original model and Schur balanced reduced model. Finally the simulation results are proposed to show the validity of the proposed method.

• Structural Engineering and Mechanics
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• 제27권3호
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• pp.263-276
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• 2007

This paper presents a fuzzy finite element model for the analysis of structures in the presence of multiple uncertainties. A new methodology to evaluate the cumulative effect of multiple uncertainties on structural response is developed in the present work. This is done by modifying Muhanna's approach for handling single uncertainty. Uncertainty in load and material properties is defined by triangular membership functions with equal spread about the crisp value. Structural response is obtained in terms of fuzzy interval displacements and rotations. The results are further post-processed to obtain interval values of bending moment, shear force and axial forces. Membership functions are constructed to depict the uncertainty in structural response. Sensitivity analysis is performed to evaluate the relative sensitivity of displacements and forces to uncertainty in structural parameters. The present work demonstrates the effectiveness of fuzzy finite element model in establishing sharp bounds to the uncertain structural response in the presence of multiple uncertainties.

• 한국항만경제학회지
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• 제32권1호
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• pp.165-178
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• 2016

컨테이너 항만은 공급망관리(SCM)에 있어서 연결점(link) 역할을 하고 있어 국제 간 무역에서 중요한 위치를 차지하고 있다. 그러므로 컨테이너 항만의 운영 상태를 파악하기 위하여 컨테이너 항만의 운영 효율성을 평가하는 것은 공급망 관리에 있어서 중요한 일이다. 과거 항만의 효율성을 측정하기 위해 많은 방법을 사용되었다. 그 가운데 자료포락분석(DEA, Data Envelopment Analysis) 방법은 가장 일반적인 방법으로 활용되고 있다. 그러나 DEA 모델에 사용되는 투입, 산출 데이터는 때때로 복잡하고 불확실하기 때문에 기존 DEA모델 사용에 한계점이 존재한다. 이 논문에서는 기존모델의 한계를 해결하기 위해 불확실변수를 취급할 수 있는 불확실성 DEA(UDEA, Uncertainty DEA)모델을 제안하였다. 제안된 불확실성 DEA모델을 이용하여 41개 컨테이너 항만의 효율성을 측정하여 불확실성 DEA 모델의 유효성을 검증하였다. 또한 항만 클러스터링 방법으로 항만의 규모별로 효율성을 측정하여 6개의 컨테이너 항만이 효율성이 있음을 식별하였다. 이와 같이 제안된 불확실성 DEA(UDEA)모델이 기존 DEA모델 보다 효율성 측정에 효과적임을 확인하였다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.2-2
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• 2000

This paper presents an adaptive control against uncertainties in tail-controlled STT (skid-to-Turn) missiles. First, we derive an analytic uncertainty model from a parametricaffine missile model developed by the authors. Based on this analytic model, an adaptive feedbacklinearizing control law accompanied by a sliding model control law is proposed. We provide analyses of stability and output tracking performance of the overall adaptive missile system. The performance and validity of the proposed adaptive control scheme is demonstrated by simulation.

• 한국정밀공학회지
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• 제28권4호
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• pp.404-409
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• 2011

Report on the notion of uncertainty is important. The reason is that the measured value includes a lot of uncertain factors. Reliable results can't be derived without the notion of uncertainty. The mathematical model to evaluate uncertainty considering the quality of vibration is important to evaluate uncertainty, and it must contain the every quantity which contributes significantly to uncertainty in the measured results. In this paper, the evaluation of uncertainty analysis about rotor vibration measurements of machine tools is presented to evaluate the most important factors of uncertainty.

• 한국수자원학회논문집
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• 제56권1호
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• pp.35-43
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• 2023

미래 유량분석은 기후변화 시나리오와 수문모형의 매개변수에 영향을 받고 이에 따른 불확실성이 존재한다. 본 연구에서는 Shared Socioeconomic Pathway (SSP) 시나리오와 수문모형 매개변수에 따른 미래 유량 분석의 불확실성을 분석하고자 하였다. SSP 시나리오 중, 대표적으로 사용되는 SSP2-4.5와 SSP5-8.5시나리오를 사용하였으며, 수문모형으로는 Soil and Water Assessment Tool (SWAT) 모형을 사용하였다. SWAT 모형의 매개변수는 SWAT-CUP을 이용해 관측된 유량 데이터에 따라 총 11개의 기간에 대해 매개변수 최적화를 각각 수행하였다. 그 후 분포의 차이를 계산 할 수 있는 Jensen-Shannon Divergence (JS-D)를 이용해 과거 유량 대비 미래 추정된 유량의 불확실성 분석을 수행하였다. 분석결과 미래 유량의 불확실성은 SSP5-8.5에서 SSP2-4.5보다 더 크게 분석되었으며, 가까운 미래(2021-2060년) 보다 먼 미래(2061-2100년)에서 더 크게 분석되었다. 강우-유출 분석은 수문모형 매개변수에 따라 88.5%-108.5%까지 차이가 발생하였으며, 이에 따라 미래 유량을 추정하는데 불확실성이 발생하였다. 본 연구에서의 수문 모형의 매개변수에 따른 미래 유량 추정의 불확실성은 평년 대비 유량이 적은 연도의 관측 유량 데이터를 이용한 매개변수를 이용할 시 불확실성이 크게 분석되었다. 또한 평년 대비 유량 변화가 큰 기간의 매개 변수일수록 미래 유량 추정의 불확실성이 크게 분석되었다.

• 한국지능시스템학회:학술대회논문집
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• 한국퍼지및지능시스템학회 2003년도 ISIS 2003
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• pp.555-558
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• 2003

The Choquet-Stieltjes integral is defined. It is shown that the Choquet -Stieltjes integral is rep-resented by a Choquet integral. As an application of the theorem above, it is shown that Choquet expected utility model for decision under uncertainty and rank dependent utility model for decision under .risk are respectively same as their simplified version.

• Nuclear Engineering and Technology
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• 제46권3호
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• pp.353-362
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• 2014

The effects of nuclear data uncertainties are studied on a typical PWR fuel assembly model in the framework of the OECD Nuclear Energy Agency UAM (Uncertainty Analysis in Modeling) expert working group. The "Fast Total Monte Carlo" method is applied on a model for the Monte Carlo transport and burnup code SERPENT. Uncertainties on $k_{\infty}$, reaction rates, two-group cross sections, inventory and local pin power density during burnup are obtained, due to transport cross sections for the actinides and fission products, fission yields and thermal scattering data.

• East Asian Economic Review
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• 제16권1호
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• pp.25-66
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• 2012

The paper analyzes the effect of expected future demand on the investment decisions of multinational enterprises. In particular, I explore the issue of the timing of switching between exporting and FDI in the host developing country and explicitly incorporate the firm's attitude toward risk in the model. The model demonstrates that the optimal time for switching to FDI depends on the expected future demand and the degree of its uncertainty.