• Wind and Structures
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• v.15 no.3
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• pp.209-221
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• 2012

The flutter reliability analysis of long span bridges requires use of a software tool that predicts the uncertainty in a flutter response due to uncertainties in the model formulation and input parameters. Existing flutter analysis numerical codes are not capable of dealing with stochastic uncertainty in the analysis of long span bridges. The goal of the present work is to develop a software tool (FREASB) to enable designers to efficiently and accurately conduct flutter reliability analysis of long span bridges. The FREASB interfaces an open-source Matlab toolbox for structural reliability analysis (FERUM) with a typical deterministic flutter analysis code. The paper presents a brief introduction to the generalized first-order reliability method implemented in FREASB and key steps involved in coupling it with a typical deterministic flutter analysis code. A numerical example concerning flutter reliability analysis of a long span suspension bridge with a main span of 1385 m is presented to demonstrate the application and effectiveness of the methodology and the software.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.52 no.2
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• pp.53-60
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• 2003

This paper deals with steady-state analysis of a single-phase line-start permanent magnet synchronous motor. In order to analyze the steady-state characteristics, the asymmetric single-phase line-start synchronous motor is converted to the symmetric two-phase synchronous motor, that is, the asymmetric magnetic field is separated from the positive and the negative symmetric components using symmetrical-component theory. The analysis method of the synchronous motor on the d-q axis coordinates is used for the positive component and the equivalent circuit of the induction motor is applied for the negative component analysis. Moreover, d-q axis inductance considering current phase angle is applied to positive component analysis for precise characteristic analysis. In order to validate the proposed analysis method, the analysis results are compared with the experimental results.

• International Journal of Highway Engineering
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• v.16 no.3
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• pp.59-66
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• 2014

PURPOSES : This study is to suggest heavy snow risk analysis in Seoul. METHODS : Recently, the increase of extreme weather caused by global warming raises the occurrences of unpredictable natural disasters and the loss potential of human disasters by land use facilities accumulation. It is necessary to develop the risk analysis for the natural and human disasters. RESULTS : In this study, heavy snow risk analysis among natural disasters in Seoul was suggested. The spatial unit of risk analysis level was established for the lines and administrative districts. CONCLUSIONS : The risk analysis was performed using risk matrix of disaster occurrence score and disaster damage score. The components affecting the risk disaster analysis by types were analyzed and the application of heavy snow risk analysis was suggested.

• Journal of Korean Academy of Nursing Administration
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• v.9 no.1
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• pp.113-128
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• 2003

Purpose : The aim of this study is to review cost analysis methodological issues in the nursing literature. Method : The subjects of this study were articles published in Korea from 1961 to August, 2002. They were searched by key words 'cost' and 'nursing' from various DB(National Assembly Library, The National Library of Korea, RICH etc). Finally, 31 articles were collected. Results : 1) The major type of cost analysis was a cost comparison study. 2) The important methodological weaknesses were as followers: First, many studies did not describe a cost analysis framework or a cost analysis assumption. Second, a few studies described selection criteria of cost items and effectiveness items. Third, many studies did not do a sensitivity analysis. Conclusion : With these results, it will be possible to develop a more proper cost analysis methodological framework and also to make an evaluation criteria for cost analysis nursing study.

• Proceedings of the Korea Concrete Institute Conference
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• 2003.11a
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• pp.301-304
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• 2003

Nowadays, hydration heat analysis using FEM is common in thermal crack control of concrete structure. Many kinds of general FEM programs for hydration heat analysis are used in practice. But there are some problems in this using. In this study hydration heat analysis of wall according to placement length are performed. In this results we could get two conclusions. First, general structures like wall having general geometry and construction condition have similar behavior. So it is not necessary to analysis thermal crack in every case. Second, the results of 2D analysis is possible to be applied instead of those of 3D analysis because the results of 2D analysis is similar to 3D analysis in long wall having about 15~18m or over length at 3m height.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.10a
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• pp.613-616
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• 1997

MDO(Multidisciplinary Design Optimization) methodology is an emerging new technology to solve a complicate structural analysis and design problem with a number of design variables and constraints. In this paper MDO methodology is adopted through the use of computer aided engineering(CAE) system. And this paper treats the structural design problem of RIROB(Reactor Inspection Robot) through the application of MDO methodology. In a MDO methodology application to the structural design of RIBOS, kinetodynamic analysis is done using a simple fluiddynamic analysis model for the warter flow over the sensor support surface instead of difficult fluid dynamic analysis. Simultaneously the structural static analysis is done to obtain the optimum structural condition. The minimum thickness (0.8cm) of the RIROB housing is obtained for the safe design of RIROB. The kinetodynamic analysis of RIROB. The kinetodynamic analysis of RIROB is done using ADAMS and the static structural analysis of RIROB is done using NISA.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.15 no.5
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• pp.18-24
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• 2016

An electromagnetic linear actuator is controlled precisely and securely and is useful in devices that require linear motion. The most commonly used method in the performance verification process for an electromagnetic actuator is finite element analysis that utilizes CAE. However, finite element analysis has the disadvantage that modeling and analysis consume a lot of time. Accordingly, lumped parameter analysis can be an alternative approach to the finite element method because of its computation iteration capability with fair accuracy. In this paper, the lumped parameter model and simulation results are presented. In addition, the results of the lumped parameter analysis are compared with those obtained from finite element analysis for verification.

• International Journal of Naval Architecture and Ocean Engineering
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• v.3 no.2
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• pp.116-121
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• 2011

The Spectral Fatigue Analysis is representative fatigue life assessment method for vessels. This Analysis is performed generally for the whole vessel and many assessment sites. The spectral fatigue analysis is performed through the process of hydrodynamic response analysis, global structural analysis, local structural analysis and calculation of fatigue damage. In these processes, fatigue damage is affected by many variables. The representative variables are S-N curve data, wave scatter data, wave spectrum, bandwidth effect and etc. In this paper, the effects of these variables to the fatigue damage are analyzed through the spectral fatigue analysis for 170k LNGC.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.18-24
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• 2010

Conventional methods for railway vehicle dynamic analysis have mostly relied on the approximate method based on 2-dimensional contact analysis. Recently, 3-dimensional approaches to achieve an accurate solution for wheel-rail contact analysis have been proposed, but are not practical to apply to actual simulation due to time-consuming processes. The main focus of this study is to present a new method of railway vehicle dynamic analysis by calculating wheel-rail contact forces based on efficient 3-dimensional wheel-rail contact analysis. A 3-dimensional wheel-rail contact analysis and numerical analysis of wheelset dynamic equations will be presented.

• Journal of Korean Society for Quality Management
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• v.22 no.2
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• pp.143-153
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• 1994

Cluster analysis is a primitive technique in which no assumptions are made concerning the data structure. And the number of groups is known a priori discriminant analysis provides an information how well N individuals are classified into their own groups. In this study, clustering, which is any partition of a collection of data points, generated by the application of eight hierarchical clustering methods was re-classified by discriminant analysis. Then correct classification ratios were obtained for the application of discriminant analysis through each clustering method and the direct application of discriminant analysis. By comparing the correct classification ratios, the applicability of cluster analysis and discriminant analysis considered.