• Nuclear Engineering and Technology
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• 제44권1호
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• pp.33-42
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• 2012

In the present study, CFD is employed to investigate phenomena occurring during a process of thermal stratification in U-bent pipes at transitional Reynolds number. URANS evaluation had been chosen for its low computational costs during transient analysis and for the evaluation of modeling performance in these conditions. Application of CFD at transitional Reynolds number and buoyancy driven flows indeed contains deeper uncertainties in relation to the range of applicability for hydrodynamic and thermal models. The methodology applied in the work points out, through validations with the basic problems constituting the complex stratified phenomenon, the applicability of the current turbulence modeling. Accurate predictions have been found in relation to transitional Reynolds number in bent pipes and region of stability induced by the gravitational field. On the other hand the defects introduced in the unstable region of the U bent pipe, are discussed in relation to the adopted modeling.

• 전기학회논문지
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• 제57권5호
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• pp.839-844
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• 2008

A novel state of health estimation method for hybrid electric vehicle lithium battery using sliding mode observer has been presented. A simple R-C circuit method has been used for the lithium battery modeling for the reduced calculation time and system resources due to the simple matrix operations. The modeling errors of simple model are compensated by the sliding mode observer. The design methodology for state of health estimation using dual sliding mode observer has been presented in step by step. The structure of the proposed system is simple and easy to implement, but it shows robust control property against modeling errors and temperature variations. The convergence of proposed observer system has been proved by the Lyapunov inequality equation and the performance of system has been verified by the sequence of urban dynamometer driving schedule test. The test results show the proposed observer system has superior tracking performance with reduced calculation time under the real driving environments.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 하계학술대회 논문집 Vol.4 No.1
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• pp.252-255
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• 2003

The pulsed laser deposition process modeling is investigated using neural networks based on radial basis function networks and multi-layer perceptron. Two input factors are examined with respect to the PL intensity. In order to minimize the joint confidence region of fabrication process with varying the conditions, D-optimal experimental design technique is performed and photoluminescence intensity is characterized by neural networks. The statistical results were then used to verify the fitness of the nonlinear process model. Based on the results, this modeling methodology can be optimized process conditions for pulsed laser deposition process.

• 정보관리학회지
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• 제14권2호
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• pp.165-189
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• 1997

기존의 모델링 방법은 분석, 설계, 구현단계에서 시스템이 수행해야 할 기능적 및 비기능적 요구를 완전하고 일관성 있게 반영할 수 있는 설계절차와 명세서가 미흡하다. 이러한 문제점은 다양한 형태의 자료와 다양한 검색방법을 요구하고 있는 문헌정보 시스템에서는 문제가 있을것으로 본다. 따라서 본 논문에서는 OMT에서 제시되고 있는 방법을 부분적으로 개선하여 시스템개발에 적용할 수 있도록 OMT를 변형한 객체모델링을 도서관 이용자 시스템 요구사항을 대상으로 설계하였다.

• 대한안전경영과학회지
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• 제6권4호
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• pp.227-238
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• 2004

This development has tried to scheme out the convenience for users to use the 3D modeling solution which is developed from the existing programs. The extended 3D modeling solution, to be developed through the use of the API which is provided and Microsoft Access, database is able to reuse the parts, subassemblies of parts, and assemblies. A methodology exhibits the possibility to use a Spinfire Professional Spinfire Reader program. The web evaluation system, which is used to connected with the Internet explorer and to construct a web service, will repeat the evaluations of the company staffs and customers about the new products which the company have designed. The furniture manufacturing company will adopt the 3D modelling solution in modelling the new products and go through the web evaluation system to collect dissatisfied facts of the customers or the company staffs against the new product. Finally, it will contribute to the enormous benefit creation of the enterprise.

• 산업공학
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• 제12권1호
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• pp.102-113
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• 1999

BOM(Bill of Material) is a description of parts, assemblies and raw materials that comprise a product structure. In manufacturing companies that produce various products with short life cycles, it is very important to manage to BOM of products with various options and versions efficiently. This paper describes an effective modeling and implementing technique of Generic BOM Management System(GBMS) for management of number of variant products. In this paper, OMT(Object Modeling Technique) was used to model a generic BOM and Object-Relational Database Management System(ORDBMS) was used to implement the GBMS database. In order to prove the effectiveness of proposed methodology, a case that assembles computer with various options was studied.

• Wind and Structures
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• 제22권5호
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• pp.543-553
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• 2016

The growing complexity of modern technological systems requires more flexible and powerful reliability analysis tools. Existing tools encounter a number of limitations including lack of modeling power to address components interactions for complex systems and lack of flexibility in handling component failure distribution. We propose a reliability modeling framework based on the Bayesian network (BN). It can combine historical data with expert judgment to treat data scarcity. The proposed methodology is applied to wind turbines reliability analysis. The observed result shows that a BN based reliability modeling is a powerful potential solution to modeling and analyzing various kinds of system components behaviors and interactions. Moreover, BN provides performing several inference approaches such as smoothing, filtering, what-if analysis, and sensitivity analysis for considering system.

• 한국전자거래학회:학술대회논문집
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• 한국전자거래학회 1999년도 학술대회지 vol.1
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• pp.207-213
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• 1999

When function modeling with IDEF0 which is called as a standard methodology for CALS (FIPS 183), the initial work is to determine the purpose and viewpoint, and the next work is to generate a data list and an activity list. This work requires participant's discussion and agreements. The main problems for these working are a communication between participants and efficient discussion processing. Brainstorming is the most useful method for this work. The paper is for development for the modeling assistant tool to promote the business modeling. In this paper, we will introduce the tool which name is 'MindMapper' and 'Dyna-IDEF'. Mind-mapper is software for mind-map method that is used for creative thinking. Using this tool, we refine the result of the brainstorming about activity list and translate the result into the functional model of IDEF0 using Dyna-IDEF. The translated functional model is prototype model without ICOM arrows.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2010년도 학술발표회
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• pp.1439-1442
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• 2010

Time-lag recurrent neural networks model (Time-Lag RNNM) is used to estimate daily pan evaporation (PE) using limited climatic variables such as max temperature ($T_{max}$), min temperature ($T_{min}$), mean wind speed ($W_{mean}$) and mean relative humidity ($RH_{mean}$). And, for the performances of Time-Lag RNNM, it is composed of training and test performances, respectively. The training and test performances are carried out using daily time series data, respectively. From this research, we evaluate the impact of Time-Lag RNNM for the modeling of the nonlinear time series data. We should, thus, construct the credible data of the daily PE using Time-Lag RNNM, and can suggest the methodology for the irrigation and drainage networks system. Furthermore, this research represents that the strong nonlinear relationship such as pan evaporation modeling can be generalized using Time-Lag RNNM.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part 1
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• pp.264-265
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• 2006

The directions of further developments in the modeling of sintering are pointed out, including multi-scale modeling of sintering, on-line sintering damage criteria, particle agglomeration, sintering with phase transformations. A true multi-scale approach is applied for the development of a new meso-macro methodology for modeling of sintering. The developed macroscopic level computational framework envelopes the mesoscopic simulators. No closed forms of constitutive relationships are assumed for the parameters of the material. The model framework is able to predict the final dimensions of the sintered specimen on a global scale and identify the granular structure in any localized area for prediction of the material properties.