• Journal of the Korean Society for Aeronautical & Space Sciences
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• 제33권3호
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• pp.18-25
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• 2005

Existing methods have performed the reliability analysis using nonlinear optimization techniques. This is mainly due to the fact that they directly apply Multidisciplinary Design Optimization(MDO) frameworks to the reliability analysis formulation. Accordingly, the reliability analysis and the Multidisciplinary Analysis(MDA) are tightly coupled in a single optimizer, which hampers utilizing the recursive and function-approximation based reliability analysis methods such as the Advanced First Order Reliability Method(AFORM). In order to utilize the efficient reliability analysis method under multidisciplinary analysis systems, we propose a new strategy named Sequential Approach on Reliability Analysis under Multidisciplinary analysis systems(SARAM). In this approach, the reliability analysis and the MDA are decomposed and arranged in a sequential manner, making a recursive loop. The efficiency of the SARAM method was verified using three illustrative examples taken from the literatures. Compared with existing methods, it showed the least number of subsystem analyses over other methods while maintaining accuracy.

• Corrosion Science and Technology
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• 제7권5호
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• pp.296-299
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• 2008

High order statistical parameters were evaluated using the electrochemical noise data collected during corrosion of type 430 stainless steel coupled to a inert, platinum electrode in 3.5% NaCl solution. High order statistical parameters are shown to predict uniform corrosion properly. However, Localization index, skewness of current, kurtosis and skewness of potential are capable of predicting pitting corrosion only when the transients are large with long life time. Of the high order statistical parameters evaluated, kurtosis of current is found to be the most sensitive parameter for detecting uniform and pitting corrosion.

• The Pure and Applied Mathematics
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• 제29권2호
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• pp.125-139
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• 2022

In this paper we wish to establish some results relating to the growths of composition of two entire functions with their corresponding left and right factors on the basis of their generalized relative order (α, β) and generalized relative lower order (α, β) where α and β are continuous non-negative functions defined on (-∞, +∞).

• Korea Journal of Hospital Management
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• 제11권2호
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• pp.61-86
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• 2006

Based on a previous literature about hospital capital structure(Shyam- Sunder & Myers, 1999), this study attempted comparison and analysis on whether the forecast of trade-off and pecking order theory could be validated in hospital's capital structure. First, this study analyzed whether hospitals follow the priority for each capital source as suggested by pecking order theory under lack of capital running in hospital. Next, it analyzed whether debt level is regressed on the average to target debt level so as to verify the validity of trade-off theory. Finally, it also analyzed possible associations between debt level and determinants of capital structure as adopted in static trade-off theory, so as to verify relative advantages of these two theories about hospital capital structure. The analysis over whole period showed that both trade-off theory and pecking order theory isn't supported particularly. This mean that each hospital's financing behaviors is different and that has not dominant financing behaviors. In the midst of separation of dispensary from medical practice, medical institutions in Korea first finances funds required using retained earnings and then use liabilities. however pecking order theory is supported, the preference of long-term liabilities and short-term liabilities is not clear. In addition, considering that debt level is in no average regression to target debt ratio, it is found that hospital capital structure following trade-off theory turns into that subject to pecking order theory via the separation of dispensary from medical practice.

• Journal of the Institute of Electronics Engineers of Korea SC
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• 제38권6호
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• pp.56-64
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• 2001

In this paper, we proposed the simple and selective method for the order of model that reflected the feature of the heart rate variability without the complicated calculation in the power spectral analysis of heart rate variability using autoregressive model. The power spectral analysis of short-term of heart rate variability using autoregressive have been problem to resolution of spectral estimates by the selective model order. As a result that the proposed method for the order comparative tested with the AIC and the fixed order method, the calculation process could become very simple and select the order which correspond with the feature of the time series. We verified it could removed the noisy power components by the fixed order.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 한국조명전기설비학회 2005년도 춘계학술대회논문집
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• pp.398-401
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• 2005

This paper presents a user-friendly application for voltage sag analysis and effective visualization for analysis date. This developed tool provides basic functions for voltage sag analysis such as load flow analysis, short circuit analysis and determination of vulnerability of sensitive equipments. Particularly it has the ability to visualize analysis results effectively using computer graphic and animation. In order to give the real sense, analysis results are displayed with geographical information in an intuitive and rapid manner. The developed voltage sag simulator is applied to the Jeju-Island power system in order to show its capabilities.

• Journal of Electrical Engineering and Technology
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• 제9권1호
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• pp.114-120
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• 2014

In this paper, a method for multi-physics analysis of the temperature-dependent properties of an oil-immersed transformer is discussed. To couple thermal fields with electromagnetic and fluid fields, an algorithm employing a user defined function (UDF) is proposed. Using electromagnetic analysis, electric power loss dependent on temperature rise is calculated; these are used as input data for multi-physics analysis in order to predict the temperature rise. A heat transfer coefficient is applied only at the outermost boundary between transformer and the atmosphere in order to reduce the analysis region. To verify the validity of the proposed method, the predicted temperature rises in high-voltage (HV) and low-voltage (LV) windings and radiators were compared with the experimental values.

• Journal of Biomedical Engineering Research
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• 제18권1호
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• pp.45-50
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• 1997

In this paper, we designed a Molter analysis system using the visual programming method It differs from the existing analysis system in that the various signal processing algorithms represented by icons were designed by GUI concept which provide unskilled user with easy and convenient analysis environment. In order to analyze ECG signal. we only select the icon representing an algorithm to be applied by mouse and arrange the selected icons upon the order to be jlrocessed on screen. As a result it provides a convenient usage and flexibility of analysis. Also, we can find the optimal algorithm for the ambulatory ECG analysis by comparing the several results obtained from the various analysis configuration.

• Communications for Statistical Applications and Methods
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• 제2권2호
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• pp.184-197
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• 1995

An objective and one-step detection procedure of multiple outliers is suggested by using the gaps of the order statistics. The detection procedure can be used as a routine outlier detection method of a statistical analysis computer program. The procedure is applied to some examples including the data selected by Kitagawa.

• 한국기계연구소 소보
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• 통권14호
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• pp.17-31
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• 1985

The Primary object of this study is to predict rigid carbody's vertical and pitch acceleration and/or displacement frequency response to vertical sinusoidal rail surface irregularities for any specified point of the carbody, and to verify the predictions by means of experiments. The developed computer program also calculates vertical and pith transmissibilities and acceleration spectra. This model can be used for first order analysis of ride behabior. it's main advantage is its simplicity and ease of use. This model can be used for first order analysis of ride quality behabior. It's main advantage is its simplicity and ease of use. The model was designed with 6 degreed of freedom. Equations of motion were derived by Lagrangian method. This calculation was applied to the vertical dynamic analysis in order to pursue a possible improvement of the dynamic performance of co-co locomotive, and results were very useful.