• 방사성폐기물학회지
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• 제16권4호
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• pp.431-439
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• 2018

Less mature nuclear reactor technologies are characterized by a greater uncertainty due to insufficient detailed design information, operational data, cost information, etc., but the expected performance characteristics of less mature options are usually more attractive in comparison with more mature ones. The greater uncertainty is, the higher economic risks associated with the project realization will be. Within a comparative evaluation of less and more mature nuclear reactor technologies, it is necessary to apply economic risk measures to balance judgments regarding the economic performance of less and more mature options. Assessments of any risk metrics involve calculating different characteristics of probability distributions of associated economic performance indicators and applying the Monte-Carlo method. This paper considers the applicability of statistical risk measures for different economic performance indicators within a trial case study on a comparative evaluation of less and more mature unspecified LWRs. The presented case study demonstrates the main trends associated with the incorporation of economic risk metrics into a comparative evaluation of less and more mature nuclear reactor technologies.

• 환경영향평가
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• 제15권3호
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• pp.165-178
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• 2006

Environmental Impact Assessment (EIA) and Environmental Management Systems (EMS) are perceived by many to be separate environmental tools. EIA serves as a systematic and predictive tool for assessing the potentially significant impacts of developments on the environment. An EMS, on the other hand, is used to consider the key impacts of operational businesses on the environment. The main difference to note is that during the EIA process impacts on developments are predicted. A proposed development has yet to be built and therefore an element of uncertainty is associated with these assessments. With an EMS, the business or organization's processes are already in operation. Even though there is also an element of prediction involved, it is a comparatively easier task to investigate what the environmental impacts of these processes are. However, in contrast with the orientation of EIA to further development actions, EMS involves the review, assessment and incremental improvement of an existing organization's environmental effects. EMS can thus be regarded as a continuation of EIA principles into the operational stage of a policy, plan, program and project. EIA may be carried out without fully supporting necessary informations to EMS.

• International Journal of Automotive Technology
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• 제8권5호
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• pp.637-650
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• 2007

A new on-line fault detection and isolation(FDI) scheme has been proposed for engines using an adaptive neural network classifier; this paper investigates the robustness of this scheme by evaluating in a wide range of operational modes. The neural classifier is made adaptive to cope with the significant parameter uncertainty, disturbances, and environmental changes. The developed scheme is capable of diagnosing faults in the on-line mode and can be directly implemented in an on-board diagnosis system(hardware). The robustness of the FDI for the closed-loop system with crankshaft speed feedback is investigated by testing it for a wide range of operational modes, including robustness against fixed and sinusoidal throttle angle inputs, change in load, change in an engine parameter, and all changes occurring simultaneously. The evaluations are performed using a mean value engine model(MVEM), which is a widely used benchmark model for engine control system and FDI system design. The simulation results confirm the robustness of the proposed method for various uncertainties and disturbances.

• 한국경제지리학회지
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• 제14권4호
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• pp.568-582
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• 2011

본 연구에서는 소무역을 둘러싼 다양한 행위 주체들의 관계를 중심으로 한 중 소무역의 성격을 규명하고, 소무역 활동이 직면하는 불확실성 내지 위험을 극복하기 위해 소무역상들이 동원하는 사회 자본을 중심으로 한 중 소무역의 운영 메커니즘을 밝혀보고자 했다. 한 중 소무역은 비공식적인 성격에도 불구하고 일자리 창출과 지역 경제의 활성화 및 이윤 추구 등 공식 부문이 당면하고 있는 사안들과 맞물리면서, 지방 정부와 세관, 기업, 그리고 해운사 등 공식 부문의 암묵적인 지원과 묵인 속에 운영되고 있다. 또한 한 중 소무역은 타 지역에서와 마찬가지로 그 운영에 있어 가족 네트워크, 민족네트워크, 사회적 네트워크 및 신뢰 등 사회 자본이 중요한 역할을 하는 것으로 나타났다.

• Smart Structures and Systems
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• 제19권1호
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• pp.39-46
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• 2017

Finite element model updating is very effective procedure to determine the uncertainty parameters in structural model and minimize the differences between experimentally and numerically identified dynamic characteristics. This procedure can be practiced with manual and automatic model updating procedures. The manual model updating involves manual changes of geometry and analyses parameters by trial and error, guided by engineering judgement. Besides, the automated updating is performed by constructing a series of loops based on optimization procedures. This paper addresses the ambient vibration based finite element model updating of long span reinforced concrete highway bridges using manual model updating procedure. Birecik Highway Bridge located on the $81^{st}km$ of Şanliurfa-Gaziantep state highway over Firat River in Turkey is selected as a case study. The structural carrier system of the bridge consists of two main parts: Arch and Beam Compartments. In this part of the paper, the arch compartment is investigated. Three dimensional finite element model of the arch compartment of the bridge is constructed using SAP2000 software to determine the dynamic characteristics, numerically. Operational Modal Analysis method is used to extract dynamic characteristics using Enhanced Frequency Domain Decomposition method. Numerically and experimentally identified dynamic characteristics are compared with each other and finite element model of the arch compartment of the bridge is updated manually by changing some uncertain parameters such as section properties, damages, boundary conditions and material properties to reduce the difference between the results. It is demonstrated that the ambient vibration measurements are enough to identify the most significant modes of long span highway bridges. Maximum differences between the natural frequencies are reduced averagely from %49.1 to %0.6 by model updating. Also, a good harmony is found between mode shapes after finite element model updating.

• 벤처창업연구
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• 제12권5호
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• pp.117-126
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• 2017

일자리 창출과 국가산업경쟁력 측면에서 중소기업의 중요성이 강조되고 있다. 글로벌 환경의 불확실성과 공급사슬 간 경쟁으로의 패러다임의 변환은 공급사슬 내 중소 공급업체의 역량에 더욱 관심이 집중되고 있다. 이러한 점에서, 공급사슬상의 구매자-공급자 관계에서 중소공급업체의 SCM(공급사슬관리) 역량이 중소공급업체의 운영성과에 미치는 영향을 실증 분석하였다. 또한 환경적 요소로서 수요불확실성이 이러한 관계에 어떤 조절효과를 미칠 수 있는지 살펴보았다. 이러한 목적을 달성하기 위해 전기 전자, 금속 기계, 자동차 등의 산업에 속한 중소공급업체를 대상으로 설문조사를 실시하였으며, 구조방정식 모형을 이용하여 관련 연구가설을 검정하였다. 연구결과, 중소 공급업체의 공급사슬역량인 관계자본은 운영성과에 유의한 정(+)의 영향을 미치는 것으로 나타나고, 조정역량은 운영성과에 유의한 영향이 나타나지 않았다. 수요 불확실성의 조절효과를 살펴보면, 관계자본 역량과 운영성과 간에는 수요불확실성의 정(+)적인 조절효과가 나타난 반면, 조정역량과 운영성과 간에는 유의한 조절효과가 나타나지 않는다. 이러한 결과는 관계자본 역량은 운영성과에 긍정적인 영향을 미치며, 수요불확실성의 상황에서도 운영성과를 제고시키는 역할을 하고 있는 것을 알 수 있다. 반면에 조정역량의 경우, 구매기업과의 핵심 비즈니스 프로세스를 통합할 수 있는 정보공유, 커뮤니케이션 등의 외부적 조정역량을 향상시킬 수 있는 프로세스의 강화와 더불어 공급사슬관련 업무를 효과적으로 수행할 수 있는 중소공급업체 내부 관련부서들 간의 조정이 뒷받침되어야 한다는 점을 시사한다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1993년도 한국자동제어학술회의논문집(국제학술편); Seoul National University, Seoul; 20-22 Oct. 1993
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• pp.321-326
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• 1993

A gain scheduling approach for the suspension control of a nonlinear MAGLEV System is presented. We show that this technique is ver useful for improving not only performance to the operational disturbances originating aerodynamic force but also robustness to the uncertainty of payload. As a scheduling variable, even though the external disturbance need to be estimated in real time, but the additive measurement is not required to do it. Some simulations show that the gain scheduling control system performs very well comparing with other method using a nonlinear feedback linearization or a fixed gain linear feedback.

• 한국시뮬레이션학회:학술대회논문집
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• 한국시뮬레이션학회 2001년도 The Seoul International Simulation Conference
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• pp.435-439
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• 2001

In many make-to-order production systems customers ask due date confirmed and kept. Unexpected urgent orders from valuable customers often requires short lead times, which causes existing orders in the production schedule to be delayed so that their confirmed due dates cannot be met. This Imposes significant uncertainty on the production schedule in a supply chain. In this paper, we propose a new concept of capacity reservation as a viable tool for due date promising and suggest its operational alternatives. Simulation results show that the reserved capacity scheme appears to outperform simple FCFS scheduling policy in terms of the number of valuable urgent orders accepted and total profit attained.

• 대한기계학회논문집
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• 제18권9호
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• pp.2257-2264
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• 1994

A method to evaluate the position performance for a stochastically defined planar robot manipulator is presented. Performance is defined as the operational reliability based upon the positional errors of the manipulator tip. An analytical method is developed and applied to a two-link robot manipulator through forward kinematics. This study includes uncertainties in the link length, pin center location and radial clearance. By virtue of the effective link length model, only the nominal manipulator model and statistical information on the uncertainties are required. The results from the analytical method is compared to those from the Monte Carlo simulation.

• 한국시스템다이내믹스연구
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• 제1권1호
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• pp.133-157
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• 2000

This paper deals with the social system from the point of system thinking consisting the fundamental construct of system dynamics. The Bertalanffy's general system theory, having been criticized because of its ambiguity, and the complex science theory, emerging system theory, are integrated by using the system thinking which is characterized with three concepts, 'feedback thinking', 'dynamic thinking', 'operational thinking'. In the integration, system thinking suggests the dynamic pattern of the social system have not only an equilibrium status but also complex status. The science of complexity gives an implication to system dynamics the important of the uncertainty and complexity if we interpret the social system as an open system. To show more concrete description, I simulate the cooperation model based on the iterated prisoner dilemma. The simulation results show the diverse patterns of cooperation and betrayal. Especially the sensitivity of initial payoff will cause the chaotic strategic landscapes as the game gose on. These results mean that we should not give the hasty prescription to control social system artificially. Because social system retains the self-organizing force in itself.