• Asia pacific journal of information systems
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• 제13권4호
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• pp.191-206
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• 2003

More views in data warehouse, can respond to the users more rapidly because the user's requests might be processed by accessing only the materialized views with higher probabilities rather than accessing base relations. But, the update duration for maintaining materialized views limits the number of materialized views in data warehouse. In this paper, we propose the algorithm for reducing update duration of materialized views, of which aggregation functions are maintained by self-maintenance. We also implement the proposed algorithm and evaluate the performance of the algorithm.

• 한국환경보건학회지
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• 제42권5호
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• pp.302-313
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• 2016

Objectives: This study was conducted to assess environmental health status on a local scale using environmental health-related indicators. It demonstrated the possibility of using a structural equation model, a methodological approach to provide synthesized information. Methods: Eighteen indicators were selected from official statistical data published by local governments. Each environmental health-related indicator was classified according to the PSR (pressure-state-response) model. Aggregation methods were performed using principal component analysis and fuzzy sets. Results: The five principal components were classified through principal component analysis (PCA) and obtained eigenvalues >1.0 from the initial 18 indicators. The aggregated index was obtained by condensing the original information into two broad and simple categories through fuzzy sets. Conclusion: This could be useful in that the aggregation procedure may provide a basis for establishing environmental health policies and a decision-making process. However, the availability and quality of indicators, assessment of aggregation method bias, choice of weighted scores for indicators, and other factors should be examined in future studies.

• 한국IT서비스학회지
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• 제14권2호
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• pp.69-86
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• 2015

The current contract awarding process regulated by laws and ordinances is analyzed and more reasonable processes are suggested. To this end, the principle of economic analysis is described with emphasis on the cost-effectiveness analysis, and the laws and ordinances regulating the process are thoroughly examined. The current contract awarding rule is based on the weighted sum of effectiveness score and cost score. This may not conform to the framework of economic analysis where effectiveness is supposed to be measured as an output and cost measured as an input. An improvement is attempted to the defense acquisition system and it is recognized that the economic analysis and policy consideration should be performed separately. Concept of statistical testing is introduced to see if the results of the cost effectiveness analyses show the significant difference between the alternatives. It is suggested that the contract awarding process can be improved by performing significance test followed by the aggregation of the two analyses. A minor improvement is also suggested on the application of current rules.

• 한국경영과학회지
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• 제22권1호
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• pp.123-140
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• 1997

In this paper we consider closed flow line systems with samploing inspections. The total number of parts in the system is assumed to be N. The processings carried out of each station do not always meet the requirement of quality. Therefore, upon completion of its processing at each station, a part is inspected to determine whether the processings meet the requirement of quality or not. We assume that inspection are done on a random basis. If a part is found to be defective by an inspection, it is fed back to the apropriate station. Two different cases will be considered in this study : a three-station flow line system with infinite buffers and a two-station flow line system with finite buffers. For each case, we will develop an exact method to obtain the performance measures such as throughput, machinen utilization, average outgoing quality and manufacturing lead time. For the case of the two-station flow line system ith finite buffers, we will also develop an approximation method using a stage-aggregation technique. Then using buffers, we will also develop an approximation method using a stage-aggregation technique. Then using these results, we will try to find an optimal inspection policy which maximizes the expected net profit under a certain cost structure. Although we present the results only for the two or three station flow line system in this paper, the results obtained in this paper can be extended easily to the system which consists of more than two or three stations.

• East Asian Economic Review
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• 제18권1호
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• pp.3-27
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• 2014

This paper examines the effects of financial crises on the long memory volatility dependency of daily exchange returns focusing on the Asian crisis in 97-98 and the Global crisis in 08-09. By using the daily KRW-USD and JPY-USD exchange rates which have different trading regions and volumes, this paper first applies both the parametric FIGARCH model and the semi-parametric Local Whittle method to estimate the long memory volatility dependency of the daily returns and the temporally aggregated returns of the two exchange rates. Then it compares the effects of the two financial crises on the long memory volatility dependency of the daily returns. The estimation results reflect that the long memory volatility dependency of the KRW-USD is generally greater than that of the JPY-USD returns and the long memory dependency of the two returns appears to be invariant to temporal aggregation. And, the two financial crises appear to affect the volatility dynamics of all the returns by inducing greater long memory dependency in the volatility process of the exchange returns, but the degree of the effects of the two crises seems to be different on the exchange rates.

• 기술혁신학회지
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• 제9권1호
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• pp.26-51
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• 2006

최근 국가 연구개발 활동에 있어서 연구개발 성과의 측정 및 관리가 중요한 이슈가 되고 있다. 특히 기술의 사업화는 연구개발의 결과물을 최종 경제적 성과로 전환하는 것으로서, 연구개발 활동의 경제적 기여를 위해 필수적인 과정이다. 이 논문에서는 국가 R&D 정책에서 중요하게 다루어지고 있는 기술사업화의 현황 및 추세를 파악하기 위하여 국가 기술사업화와 관련된 다양한 정보들을 종합한 국가기술사업화지표를 개발하였다. 개발된 지표는 기술사업화 활동, 협력 및 네트워크, 기술사업화 성과 기술사업화 환경, 심리지수의 다섯 가지 부문으로 구성되어 있고 각 부문의 지수는 각각 다섯 개의 세부 지표로 구성되어 있다. 개발된 지표는 우리나라의 기술시장 및 사업화 정책 수립을 위한 유용한 기초 자료로서 기술사업화 현황 및 수준, 예측 등 다양한 정보를 제공할 것이다.

• 보건행정학회지
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• 제23권2호
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• pp.176-187
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• 2013

Background: In 2006 Emergency Medical Services Index (EMSI), which summarizes the performance of regional emergency medical services system, was developed. This study assesses the performance of the EMSI to help determine whether EMSI can be used as evaluation tool. Methods: To build a composite score of the EMSI from predefined 24 indicators, 3 normalized values were calculated for each indicator, the normalized values of each indicator were weighted using 4 weighting methods, and the weighted values were aggregated into the final composite score using 2 aggregation schemes. The performance of EMSI was evaluated using 3 criteria: discrimination, construct validity, and sensitivity. Discrimination was the proportion of regions that did not include the overall median rank in the 5th to 95th percentiles rank interval, which was calculated from Monte Carlo simulation. Construct validity was a correlation among the alternative EMSIs. Sensitivity of EMSIs was evaluated by total shift of quartile membership and changes of 5th to 95th percentile intervals. Results: The total discrimination performance of the EMSI was 50.0%. Correlation coefficients between EMSIs using standardized values and those using rescaled values ranged from 0.621 to 0.997. Variation of the quartile membership of regions ranged from 0.0% to 75.0%. The total change in the 5th to 95th percentile intervals ranged from -19 to +17 places. Conclusion: The results suggested that the EMSI could be used as a tool for evaluating quality of regional EMS system and for identifying the areas for quality improvement.

• 국제지역연구
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• 제22권2호
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• pp.93-119
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• 2018

2004년부터 2013년까지 계속된 중국의 자동차 소비자 보호 정책 수립과정에서 소비자, 제조 업체, 판매 대리상, 수리업체 사이에 이익 표출과 이익집약이 반영되었다. 특히 중국소비자협회의 노력과 수정 안건 제시로 분산된 소비자들의 이익이 표출되는데 성공했다. 그리고 판매 업체들은 중국 자동차 유통협회를 통해 자동차 제조업체에 책임을 추궁할 수 있는 권리를 최종 규정에 넣었다. 마지막으로 자동차 업체들의 적극적인 이익 표출로 인해 정책 수립이 지연되기도 하고 소비자들에게 이익이 되는 정책을 촉진시키기도 하였다. 따라서 중국의 자동차 소비자 보호 정책 수립과정을 통해 본 중국의 국가-사회관계는 단순히 국가조합주의로 환원시키기에는 한계가 있고, 사회조합주의와 같은 상향식 이익 표출과 정책수정 활동 역시 중요하다는 것을 알 수 있다.

• 수산경영론집
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• 제41권2호
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• pp.107-133
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• 2010

As policy makers are often concerned about dynamic effects of demand behavior and its welfare analysis by quantity changes, the paper shows how dynamic price formation systems can be built up to analyze the effect of policy options to the markets dynamically. The paper develops dynamic model of price formation for fish from the intertemporal optimization of the consumer choice problem. While the resulting model has a similar form of the error correction types of dynamic price formation system, it provides the rational demand behavior contrary to the myopic behavior of error correction demand models. The paper also develops appropriate tools of dynamic welfare analysis in quantity space using only short-run demand estimates both theoretically and empirically as a first attempt in the literature of price formation and fisheries. The empirical results of Korean fish markets show that the dynamic model and the welfare measures are reasonably plausible. The methodology and theory of this research can be applied and extended to the commodity aggregation, dynamic demand estimation, and dynamic welfare effects of regulation in the similar framework. Thus, it is hoped that this will enhance its applications to the demand-side economics.

• 한국CDE학회논문집
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• 제9권4호
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• pp.361-372
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• 2004

Collaborative and distributed engineering web services are emerging as a viable alternative to the traditional design and engineering process automation. Existing approaches have limitations in supporting long-running engineering transactions, automatic engineering process orchestration and choreography, synchronous and asynchronous conversation, and geometric abstraction for transmission and sharing. In this paper, we present a process-centric engineering web service methodology to overcome these limitations by utilizing BPEL-based (Business Process Execution Language) process templates and coordination broker-based conversation support. This paper discusses the synchronization of engineering web services which can be either peer-centric or process-centric to support long-running engineering transactions and conversation. The process orchestration and choreography broker works as a service dispatching and aggregation mediator for executing process templates, which enables the individual activity or the engineering process to dynamically select and invoke one of the alternative web services through the run-time process brokering. Further, the paper presents how to support collaboration over the running process using conversation policy.