• Journal of Korean Society for Atmospheric Environment
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• v.9 no.3
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• pp.207-215
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• 1993

In order to statistically predict $O_3$ levels in Seoul, the study used the TMS (telemeted air monitoring system) data from the Department of Environment, which have monitored at 20 sites in 1989 and 1990. Each data in each site was characterized by 6 major criteria pollutants ($SO_2, TSP, CO, NO_2, THC, and O_3$) and 2 meteorological parameters, such as wind speed and wind direction. To select proper variables and to determine each pollutant's behavior, univariate statistical analyses were extensively studied in the beginning, and then various applied statistical techniques like cluster analysis, regression analysis, and expert system have been intensively examined. For the initial study of high level $O_3$ prediction, the raw data set in each site was separated into 2 group based on 60 ppb $O_3$ level. A hierarchical cluster analysis was applied to classify the group based on 60 ppb $O_3$ into small calsses. Each class in each site has its own pattern. Next, multiple regression for each class was repeatedly applied to determine an $O_3$ prediction submodel and to determine outliers in each class based on a certain level of standardized redisual. Thus, a prediction submodel for each homogeneous class could be obtained. The study was extended to model $O_3$ prediction for both on-time basis and 1-hr after basis. Finally, an expect system was used to build a unified classification rule based on examples of the homogenous classes for all of sites. Thus, a concept of high level $O_3$ prediction model was developed for one of $O_3$ alert systems.

• Journal of the Korea Society for Simulation
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• v.19 no.4
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• pp.319-326
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• 2010

Effectiveness analysis of weapon system has been accomplished using engagement-level model alone. However, most previous works are prone to errors due to lack of behavioral information about the weapon systems. In order to overcome these limitations, this paper proposes an interoperation approach between the engagement- and engineering-level models. The proposed approach enables the engagement-level model to be supported by the engineering-level model representing the detailed behavior of weapon systems. Our methodology consider a limited combat situation including operational environments, dynamics and operational errors of weapons, and engagement orders. The paper describes a formalization of the system effectiveness analysis and defines an interface for interoperation between engagement- and engineering-level models. Then, we perform an anti-torpedo combat simulation as a case study.

• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.10
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• pp.56-63
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• 2015

Not only performance analysis but also power analysis at early design stages is important in designing a system-on-chip. We propose a power modeling based on clock gating enable signals that enables accurate power analysis at a high-level. Power state is defined as combinations of the values of the clock gating enable signals and we can extract the clock gating enable signals to generate the power model automatically. Experimental results show that the average power accuracy is about 96% and the speed gain of power analysis at the high-level power is about 280 times compared to that at the gate-level.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.52 no.7
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• pp.363-370
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• 2003

This paper presents the analysis of the load transfer capacity and study of conductor size for variable contingencies in distribution systems. The operation capacity of feeders was changed to improve operation efficiency in KEPCO, considerations for contingencies are still based on the previous capacity. In order to cope with the changes such as operation capacity, it is necessary to study whether the present "contingency support criteria" is reasonable or not, also to confirm the whether the present criteria should be improved or not. We analyze the load transfer capacity and conductor size on a distribution system for contingency levels such as the substation-level, bank-level, feeder-level, and zone-level.one-level.

• Asia pacific journal of information systems
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• v.11 no.3
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• pp.105-126
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• 2001

The objective of research is to find out exogenous variables that influence the usage and performance EDI in the Korea firms. Specifically the goals of this research are; (1) to examine relationships between exogenous variables, such as management, technology, inter-firm relationship characteristics, and EDI performance, and (2) to measure EDI volume, EDI diversity, EDI depth among Korea firms. The questionnaire consists of two versions; One for the EDI system managers and the other for the EDI users. The analysis of this study is designed as cross level to examine the causal relationship among variables in different analysis level. The reliability and validity of data was tested by explanatory factor analysis, Cronbach's alpha coefficient, confirmatory factor analysis, and correlation analysis. Also, the structural equation model(SEM) analysis was performed to test the usefulness of the model. The analysis results revealed that education level, IS growth, trust, support, power are major influential variables on the usage level and performance of EDI. Especially, persuasive power turned out to be more important than coercive power, and technical financial support from organizations was also found to be a significant variables.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.26 no.3
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• pp.199-205
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• 2013

In this study, the methodology for the fatigue life prediction using finite element method(FEM) in wire, bundle and assembly level of the wire harness system and the development of the fatigue life test machine for the numerical analysis are investigated. To obtain stress-life(S-N) histories of the componential wires of the system, five kinds of wires are prepared and applied to the repeated bending motion using developed fatigue life test equipment. Equivalent model of the wire from the rule of mixtures theory is used for the material modeling of sheath and wire core combination. Contact conditions among the wires, taping conditions are established through the bundle level test and numerical bundle analysis. Wire and bundle level results are adopted for the assembly level analysis. For the assembly level analysis, real wire harness system including bundle and grommet is numerically modeled and applied contact condition between wires with real opening motion. The fatigue life more than 700,000 cycles of the assembly is obtained from the FEM, and it is confirmed that the result has good agreement with the experimental result.

• Korea Journal of Hospital Management
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• v.17 no.3
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• pp.1-22
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• 2012

The purpose of this study is to analyze the mediating effect of informatization level between characteristics of introducing information system and organizational performance in hospital settings, and to provide suggestions to improve the performance level of strategic information system of hospitals. In order to achieve study purpose, a causal path model was developed and empirically tested. Data were collected from 746 managers of 92 hospitals keeping information system in Busan, Ulsan and Kyungnam Province using self-administered structured questionnaire. Major results of this study were as follows; The results of the path analysis showed that organizational characteristics variables except informatization strength within health industry had significant effects on informatization level, and had indirect effects on organizational performance mediated by informatization level. On the other hand, informatization level, especially revelation capability among informatization level variables, was found to have significant direct effect on organizational performance. These results of empirical test imply that informatization level variables are both important affecting factors on organizational performance and mediating factors between organizational characteristics and organizational performance. Therefore, in order to increase organizational performance, measures improving informatization level should be developed and carried out continuously. And, especially, focusing on building and strengthening revelation capability is crucial to those efforts.

• Journal of the Earthquake Engineering Society of Korea
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• v.18 no.3
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• pp.141-150
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• 2014

A methodology to evaluate the seismic performance of interface piping systems that cross the isolation interface in the seismically isolated nuclear power plant (NPP) was developed. The developed methodology was applied to the safety-related interface piping system to demonstrate the seismic performance of the target piping system. Not only the seismic performance for the design level earthquakes but also the performance for the beyond design level earthquakes were evaluated. Two artificial seismic ground input motions which were matched to the design response spectra and two historical earthquake ground motions were used for the seismic analysis of piping system. The preliminary performance evaluation results show that the excessive relative displacements can occur in the seismically isolated piping system. If the input ground motion contained relatively high energy in the low frequency region, we could find that the stress response of the piping system exceed the allowable stress level even though the intensity of the input ground motion is equal to the design level earthquake. The structural responses and seismic performances of piping system were varied sensitively with respect to the intensities and frequency contents of input ground motions. Therefore, for the application of isolation system to NPPs and the verification of the safety of piping system, the seismic performance of the piping system subjected to the earthquake at the target NPP site should be evaluated firstly.

• Land and Housing Review
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• v.2 no.3
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• pp.249-258
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• 2011

In order to achieve an efficient urban regeneration of the nation, it is required to determine the extent of decline nation-wide and the declined areas for each district and also to evaluate the potentials of the concerned areas. For this task to be accomplished, a construction of a comprehensive diagnostic system based on spatial information considering diversity and complexity is required. In this study, a total information system architecture for urban regeneration is designed as part of the construction of such a diagnostic system. In order to develop the system, a city and district level unit decline diagnostic indicators has been constructed and a decline diagnostic system has been developed. Also, a scheme to promote the advancement of the system is proposed. The DB construction is based on the city and district level nation-wide and metadata for the concerned level is constructed as well. The system is based on the Open API and designed to be flexible for extension. Also, an RIA-based intuitive UI has been implemented. Main features of the system consist of the management of the indicators, diagnostic analysis (city and district level decline diagnosis), related information, etc. As for methods for the advancement, an information model in consideration of the spation relations of the urban regeneration DB has been designed and application methods of semantic webs. Also, for improvement methods for district unit analytical model, district level analysis models, GIS based spatial analysis platforms and linked utiliation of KOPSS analysis modules are suggested. A use of a total information system for urban regeneration is anticipated to facilitate concerned policy making through the identification of the status of city declines to identify and the understanding of the demands for regeneration.

• Journal of Families and Better Life
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• v.9 no.2
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• pp.103-117
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• 1991

The purpose of this study was to investigate causal relations of resources and demands, family financial management and subjective financial wee-being among urban households by applying a system's approach. The data were collected through the questionnaire whose respondent were 455 housewives in Seoul. The data were analyzed by various statistical methods such as Frequency. Percentile, ANOVA , F-test, T-test, Pearson's correlation analysis, Multiple Regression Analysis. Path Analysis. The results of this research were as follows. 1) The level of subjective financial wee-being among urban households exceeded the middle level. It had significant differences according to resource variables such as age of housewife. education level of housewife, housewife's occupation, househead's occupation. per capita income, debt/net asset ratio, and according to demand variables such as aspiration, expectancy, perception of financial progress, relative deprivation. 2) The level of subjective financial well-being among urban households according to level of family financial management capability has significant differences. Therefore, the higher family financial management capability, the higher level of subjective financial well-being. 3) Among all variables affecting the subjective financial well-being among urban households. aspiration had the highest relative influence on the subjective financial well-being and per capita income, occupation of househead and family financial management variables were in this order. 4) Among all variables affecting the subjective financial well-being among urban households aspiration, occupation of househead, per capita income and finacial management variables had direct effect on subjective financial well-being . Besides housewife's education level, aspiration and per capita income had indirect effect on it through family financial management.