• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.10a
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• pp.830-835
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• 1995

To quickly determine the effect of the substitute component on the machine's performance is very important in the defign and the manufacturing processes. And minimizing machine cost and maximizing machine quality mandata predictability of machine accuracy. In the study, in order to evaluate the effects of the component's geometric errors and dimensions on the machining accuracy of gantry-type 5-axis machining centers, a geometric error analysis and virtual manufacturing system is developed based on the mathematical model for the shape generation motion of machine tool considering the component's geometric errors and dimensions, the solid modeling techniques and so on.

• Journal of Industrial Technology
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• v.28 no.B
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• pp.227-234
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• 2008

Reliability predictions for selected electronic parts using 217-Plus have been performed in this study. 217-Plus has recently developed and may be applied for electronics failure prediction as a surrogate of MIL-HDBK-217. We first briefly reviewed 217-Plus component models. Based on three selected components, predictions using both MIL-HDBK-217 and 217-Plus have been made and the results were compared. Even though the comprehensive conclusion may be drawn from extensive component and system level analyses, the results in this study may provide general insights towards reliability through two specifications.

• Journal of the Korean Data and Information Science Society
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• v.14 no.4
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• pp.751-758
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• 2003

We consider a life testing experiment in which several two-component shared parallel systems are put on test, and the test is terminated at a predesigned experiment time. The bivariate data obtained from such a system-level life testing can be classified into three cases: 1) the case of failed two components with known failures times, 2) the case of censored two components, and 3) the case of one censored component and the other failed component of which the failure time might be known or unknown. In this thesis, the likelihood estimators for Freund's bivariate exponential life distribution under above censoring scheme are obtained. Results of comparative studies based on Monte Carlo simulation are presented.

• KSCI Review
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• v.2 no.2
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• pp.7-18
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• 1996

In this paper library is proposed to store and retrieve the software components, in addition to that designed and implemented the user interface for management and control of this library. Applying components to this library for version control, component's quantitative testing are processed. In the case of user selection of component's a high quantative rate components can be selected.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.629-630
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• 2008

Before applying the HTS power cable to the real utility, the system needs to be analyzed using certain simulation tools. The impedance of superconductor is changed due to the magnitude of current, temperature, and magnetic field. PSCAD/EMTDC does not provide the superconductor component which has the impedance characteristic. The authors have developed the HTS power cable component in EMTDC program which included the same electrical characteristics as real HTS power cable previously. Based on the research results, the authors analyzed fault current characteristics of HTS power cable using the developed EMTDC model component.

• Proceedings of the Korea Database Society Conference
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• 2008.05a
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• pp.369-377
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• 2008

This paper is to provide the method of dynamic service composition in ubiquitous environment. This method is extended of Service Component Architecture, which is a standard about service composition. This standard only supports service composition in system design time. It has problem we cannot it ubiquitous environment, requests dynamic service composition. To solve this problem, we suggest dynamic service composition method based on SCA.

• KIEE International Transactions on Power Engineering
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• v.2A no.4
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• pp.153-159
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• 2002

Power transformer protective relay should block the tripping during magnetizing inrush and rapidly operate the tripping during internal faults. Recently, the frequency environment of power system has been made more complicated and the quantity of 2nd frequency component in inrush state has been decreased because of the improvement of core steel. And then, traditional approaches will likely be maloperate in the case of magnetizing inrush with low second harmonic component and internal faults with high second harmonic component. This paper proposes a new relaying algorithm to enhance the fault detection sensitivities of conventional techniques by using a fuzzy logic approach. The proposed fuzzy based relaying algorithm consists of flux-differential current derivative curve, harmonic restraint, and percentage differential characteristic curve. The proposed relaying was tested with relaying signals obtained from EMTP simulation package and showed a fast and accurate trip operation.

• Journal of Korean Society for Geospatial Information Science
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• v.8 no.1 s.15
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• pp.65-72
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• 2000

Travel demand forecasting is the important process of transportation policy and planning, especially trip assignment is also important because it finds deficiency of network GIS can be applied to transportation due to its various merits. Recently Program development environment is changed to component-based and transportation-component is necessary. This study evolves in implementing trip assignment model with GIS and tries to apply the system to the Cheongju City.

• Journal of the Korea Society of Computer and Information
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• v.22 no.6
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• pp.131-140
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• 2017

As video equipments such as CCTV are used for various purposes in fields of society, digital video data processing technology such as automatic motion detection is essential. In this paper, we proposed and implemented a more stable and accurate motion detection system based on background subtraction technique. We could improve the accuracy and stability of motion detection over existing methods by efficiently processing color information of digital image data. We divided the procedure of color information processing into each components of color information : brightness component, color component of color information and merge them. We can process each component's characteristics with maximum consideration. Our color information processing provides more efficient color information in motion detection than the existing methods. We improved the success rate of motion detection by our background update process that analyzed the characteristics of the moving background in the natural environment and reflected it to the background image.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.3 no.3
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• pp.23-34
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• 1980

The method of principal component analysis is originated by K. Pearson, who considered this as geometrical method Principal component analysis is the most elementary method, and this means that the information having various type of characteristics which have been correlated among themselves, are summarized by orthogonal transformations of characteristics. I: Even though we have different result whether this method is applied to homogeneous population or not. In this research we should deal with the case of homogeneous population only. II: On the other hand, we can have different result whether we start from covariance matrix or matrix of correlation- coefficients. In this research we are studying based on covariance matrix.