• 대한안전경영과학회지
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• 제16권3호
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• pp.239-248
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• 2014

Most systems used in industrial sites, actually have non-linearity and uncertainty. Therefore there are a lot of difficulties in evaluating conditions of these systems. Generally, the quantitative analysis and expression are found hard because the general public cannot easily make an accurate interpretation on the systems. Thus development of a system that utilizes an expertise from skilled analysts is required. In this research, a real-time sensor signal conditioning system and Fuzzy-expert system have been separately set up into an inference algorithm. So that it ensures a fast, accurate, objective and quantitative operational condition value provided to the manager. Therefore, FE_AFCDM is suggested in this literature, as an effective system for diagnosing the problems related to the air compressor. It can quantify the uncertain and absurd condition to operate the air compressor facilities safely and financially.

• 조명전기설비학회논문지
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• 제23권2호
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• pp.148-153
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• 2009

FMECA는 전력설비의 기능, 고장 모드, 고장 원인 및 고장의 파급 효과 등을 분석하고 각 고장 모드가 시스템의 기능 유지에 영향을 미치는 정도인 심각도(Severity)와 고장 발생의 빈도의 정도인 치명도(Criticality)를 평가하여 치명도 매트릭스(Criticality Matrix)를 구성함으로써 높은 위험성을 갖는 고장 모드를 판별하고 효과적인 시스템 구성을 위한 참고 자료를 제공한다[4-5]. 대부분의 경우, 고장 모드의 두 지수는 미리 정해진 기준에 따라 전문가들의 정성적인 평가에 의해 결정된다. 따라서 본 논문에서는 두 지수들에 대한 다양한 전문가의 의견을 종합하여 결론을 도출하기 위한 방법론으로 기존의 Linear Opinion Pool에 퍼지이론을 결합하는 방식을 제안하였다. 또한 기존의 치명도 매트릭스 방식으로 위험도를 판별하던 방식의 한계를 인식하고 운영자의 관심에 따라 두 지수를 종합적으로 평가하기 위해 퍼지 FMECA 전문가 시스템을 구성하였다.[7-8]. 사례연구에서는 대표적인 전력 설비에 대한 적용 예를 나타내었다.

• 농촌계획
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• 제16권3호
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• pp.11-17
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• 2010

With international attention to the rural landscape, there have been landscape management and conservation efforts. Because it contains characteristics of rural area, rural landscape has been recognized as an important component of rurality. With rural amenity resources survey projects launched since 2005, rural landscape categorization and evaluation such as resource value, use value, beauty, originality, traditionality, maintenance are performed by expert questionnaire survey and 100 rural amenity resources are selected. In this study, we performed fractal analysis for developing evaluation system of the rural landscape photographs. In evaluating processes, main and surrounding landscape are separated and fractal indexes are calculated and analyzed with beauty value scoured by experts. Results show that beauty value is not significantly related with fractal index but differences of main and surrounding landscape fractal index.

• Nuclear Engineering and Technology
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• 제46권5호
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• pp.619-632
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• 2014

The Best Estimate Plus Uncertainty (BEPU) method has been widely used to evaluate the uncertainty of a best-estimate thermal hydraulic system code against a figure of merit. This uncertainty is typically evaluated based on the physical model's uncertainties determined by expert judgment. This paper introduces the application of data assimilation methodology to determine the uncertainty bands of the physical models, e.g., the mean value and standard deviation of the parameters, based upon the statistical approach rather than expert judgment. Data assimilation suggests a mathematical methodology for the best estimate bias and the uncertainties of the physical models which optimize the system response following the calibration of model parameters and responses. The mathematical approaches include deterministic and probabilistic methods of data assimilation to solve both linear and nonlinear problems with the a posteriori distribution of parameters derived based on Bayes' theorem. The inverse problem was solved analytically to obtain the mean value and standard deviation of the parameters assuming Gaussian distributions for the parameters and responses, and a sampling method was utilized to illustrate the non-Gaussian a posteriori distributions of parameters. SPACE is used to demonstrate the data assimilation method by determining the bias and the uncertainty bands of the physical models employing Bennett's heated tube test data and Becker's post critical heat flux experimental data. Based on the results of the data assimilation process, the major sources of the modeling uncertainties were identified for further model development.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2018년도 추계학술대회
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• pp.27-30
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• 2018

의사결정나무를 이용한 토마토 스마트 팜 용 전문가시스템을 설계하여 각 하우스의 주변 환경에 따라 달라지는 요소들에 의해 생성되는 데이터를 사용하여 보다 농민의 결정과 비슷한 의사결정구조를 가진 제어시스템을 구축한다. 현재 스마트 팜의 제어시스템은 지금까지 농민들이 해온 방식과 유사하게 스스로 제어하지 못하였기에 스마트 팜 제어시스템의 의존율은 여전히 높지 못하다. 스마트 팜 내의 센서 값 등 주변 환경을 기준으로 한 환경제어에 농민들의 직접적인 개입이 필수불가결 하다. 그래서 보다 농민의 의사결정과 비슷한 시스템을 만들기 위하여 전문가시스템에 의사결정나무를 접목시킨 제어기를 설계하는 것을 목표로 하였다. 하우스 내의 장비를 제어하기에 앞서 여러 환경요소 중에 가장 직접적인 영향을 미치는 것을 자동으로 선정한 후, 농민들의 의사결정 선정기준을 포함시켜 복합적인제어를 위하여 전문가시스템을 구축한다. 이번 연구는 무거운 툴을 사용하지 않고 데이터를 이용하여 결과를 도출하는 것에 초점을 맞추어 진행하였다. 현재 많은 농장에서 스마트 팜을 이용한 데이터들이 쏟아져 나오고 있고 이것을 농민들이 손쉽고 빠르게 접근하여 직접적인 개입을 줄일 수 있는 방법론에 대한 표준이 될 수 있을 것으로 예상 한다.

• Journal of Mechanical Science and Technology
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• 제19권4호
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• pp.985-992
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• 2005

Vehicle Stability Control (VSC) system prevents vehicle from spinning or drifting out mainly by braking intervention. Although a control threshold of conventional VSC is designed by vehicle characteristics and centered on average drivers, it can be a redundancy to expert drivers in critical driving conditions. In this study, a manual adaptation of VSC is investigated by changing the control threshold. A control threshold can be determined by phase plane analysis of side slip angle and angular velocity which is established with various vehicle speeds and steering angles. Since vehicle side slip angle is impossible to be obtained by commercially available sensors, a side slip angle is designed and evaluated with test results. By using the estimated value, phase plane analysis is applied to determine control threshold. To evaluate an effect of control threshold, we applied a 23-DOF vehicle nonlinear model with a vehicle planar motion model based sliding controller. Controller gains are tuned as the control threshold changed. A VSC with various control thresholds makes VSC more flexible with respect to individual driver characteristics.

• 국제학술발표논문집
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• The 6th International Conference on Construction Engineering and Project Management
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• pp.696-697
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• 2015

Cost, schedule, and quality are the three major performance indicators for any construction project. Under the globalized competition in the nuclear industry, researchers and practitioners have also explored a systemized and integrated management system for cost, schedule, and quality. In order to address this issue, the concept of earned value management system (EVMS) has been often utilized. However, implementing EVMS for a mega-project of nuclear power plant (NPP) construction requires extensive overhead efforts. Though previous studies proposed structures and methods for effective NPP EVMS, there has been no legitimate study for data collection strategy for practical implementation. In this context, the purpose of this paper is to develop an effective data collection strategy for NPP EVMS. Firstly, the barriers to practical NPP EVMS were identified based on literature review and expert interviews. Strategies for data collection were then developed based on different phases of project life cycle. This study focuses on the 'life-cycle integrated progress management system' for NPP construction from an owner's perspective Therefore, results of this study can be used as a guide for preparing request for proposals (RFP) of an NPP owner organization.

• 한국건설관리학회논문집
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• 제15권2호
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• pp.71-78
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• 2014

국내 건설산업의 효율성 제고와 건설프로젝트의 가치를 향상시키기 위해 VE제도가 도입 된지도 30여년의 시간이 지났으나 국내 현실은 프로젝트의 기능분석 과정에 많은 시간과 노력을 투자하지 못하고 있으며, 이를 바탕으로 해야 할 전문가 협업워크숍 부분이 부족하여 창의적인 아이디어의 도출이 부족하게 되고 결과적으로 VE활동은 설계검토와 비용절감 부분에 초점이 맞추어지는 것이 현실이다. 이를 개선하기 위해서는 체계화된 VE Job Plan 프로세스와 워크숍 협업 전산시스템이 필요하다. 본 연구에서는 프로젝트 의사결정을 위한 기능분석 및 FAST도 전산모델, 웹기반 VE워크숍 수행 및 프로젝트 의사결정프로그램을 제안하였으며, 이는 기능향상 및 비용절감을 목적으로 하는 다양한 분야에서 활용이 가능한 시스템이며 객관적인 성능 및 기능분석을 실행하여 다양한 이해관계에 놓인 의사결정자의 신속한 의사결정을 지원하며 VE업무 효율화를 극대화시킬 수 있으리라 기대된다.

• 산업경영시스템학회지
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• 제4권4호
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• pp.63-69
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• 1981

As enterprises are getting bigger and bigger and more competecious, an engineering economy for the maximization of profit based on basic theory must be considered. This thesis present dynamic computer model for the decision which controls complicated and various man- machine system optimally. This model occur in general stage can be adaptable to every kind of enterprises. So, any one who has no expert knowledge is able to get the optimal solution. And decision tree used in this paper can be applied in every kinds of academic circles as well as whole the industrial world. This paper studied optimal management of engineering project based upon basic theory of engineering economy. It introduces and functionizes the variables which generalize every possible elements, set up a model in order to find out the variable which maximize the calculated value among many other variables. And the selected values ate used as decision- marking variables for the optimal management of engineering projects. It found out some problem of this model. They are : 1. In some kinds of man-machine system it refers to Probability, but other case, it depends on only experimental probability. 2. Unless decision making process (decision tree) goes on, this model can not be applied. So these cases, this paper says, can be solved by adapting finite decision tree which is analyzed by using the same technic as those in product introduction problem. And this paper set up the computer model in order to control every procedure quickly and optimally, using Fortran IV.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 2000년도 추계 학술발표회 논문집 Proceedings of EESK Conference-Fall 2000
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• pp.251-260
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• 2000

Seismic performance evaluation systems require rational classification of structure systems, proper evaluation criteria, and their scoring index for synthesis. Current seismic performance systems need expert judgments based on collection of available data, approximate analysis of important items, and various scoring system. This study presents a three-step seismic performance evaluation system for building structures in Korea. Each evaluation step determines the seismic performance and the method depends on the degree of refinement of analysis. The preliminary step evaluation involves the global attributes of structures such as vertical irregularity, asymmetric plan, redundancy, and age of structures. The second step requires an elastic analysis for estimation of forces acting on critical sections and checks the strength and ductility. The final step requires inelastic capacity of structures. Each stephas own evaluation scheme with proper weighing factor dependent on the importance and consequence. This study applies the fuzzy theory to a scoring method that synthesizes the individual quantity to a representative value.