• Proceedings of the Korean Institute of Building Construction Conference
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• 2016.05a
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• pp.237-238
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• 2016

Rework is a major cause that adversely affects the performance of a construction project, such as schedule delay or cost overrun. In order to prevent rework, research has been mainly conducted to analyze the cause of rework, but limited to quantitatively measure cost of rework and analyze its impact on project performance. Therefore, this paper aims to analyze impact of rework cost using 369 rework items collected from 3 construction site. This research is expected to accurately determine control target of rework and to improve efficiency of business operations in construction project.

• KIEE International Transactions on Power Engineering
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• v.4A no.3
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• pp.159-166
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• 2004

Forecasting prices in electricity markets is critical for consumers and producers in planning their operations and managing their price risk. We utilize the generalized autoregressive conditionally heteroskedastic (GARCH) method to forecast the electricity prices in two regions of New York： New York City and Central New York State. We contrast the one-day forecasts of the GARCH against techniques such as dynamic regression, transfer function models, and exponential smoothing. We also examine the effect on our forecasting of omitting some of the extreme values in the electricity prices. We show that accounting for the extreme values and the heteroskedactic variance in the electricity price time-series can significantly improve the accuracy of the forecasting. Additionally, we document the higher volatility in New York City electricity prices. Differences in volatility between regions are important in the pricing of electricity options and for analyzing market performance.

• Korean journal of food and cookery science
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• v.23 no.5
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• pp.677-684
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• 2007

This study analyzed the influence service quality has on customers satisfaction and revisits to foodservice enterprises located in the Jeonju area. The result are as followings. First, factor analysis was performed with 25 variables, drawing out five accessibility, materiality, assurance, speciality, and correspondence. Second, study model analysis showed that the service quality of foodservice operations located in the Jeonju area had an influence on customers satisfaction. This was especially significant for the factors of accessibility and materiality. Third, when considering customer satisfaction with restaurants, satisfaction with the area's image, and satisfaction with the area's sightseeing, we found that satisfaction with the restaurants and satisfaction with the area's image influenced revisits. This suggests that the higher a customer's satisfaction the more foodservice businesses they want to visit. Thus the foodservice businesses located in the Jeonju area must promote service quality so that customers are satisfied and repeatedly visit the restaurants.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.139-142
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• 2008

Construction Management by using 4D CAD system analyzes operations information based on 3D and 4D objects. But it is difficult to provide a variety of documents linked by 4D objects in a lump from 4D CAD system based on visual object, and to get an optimal decision-making information to conduct business. Therefore, it is necessary to construct effective construction information management systems and to organize integrated information through linking non-objects to objects. This study suggests methodologies of effective construction management for railway facilities through building of framework for practical application and methodologies to link 4D objects to IETM documents. Accordingly, it is possible to establish a systematic decision-making for an effective construction management of railway facilities, and this provide integrated methodology for linking non-objects to objects.

• Korean Management Science Review
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• v.21 no.2
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• pp.27-42
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• 2004

Assimilation is defined as the extent to which the use of a technology diffuses across organizational work processes and becomes routinized in the activities associated with those processes. Assimilation is an important construct in the casual chain of influence from the organizational adoption of an information technology to the evidence of its impacts on business performance. Given a wide range of experiences with the effective assimilation of Web technologies. there is a need to discover how firms can institutionally encourage the managerial activities that will result in greater levels of technology assimilation. This study analyzes or shows which organizational and strategical factors like management belief. management participation. strategic investment rationale and coordination mechanism have impact on the assimilation of web technologies. Moreover. this research is tried under the different types of firms. manufacturing and service firms. The result shows that the management belief among the determinants had a significant effect on the assimilation of web technology. However. the result would be generalized with the inclusion of the psychological factors to the current model.

• Management Science and Financial Engineering
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• v.13 no.1
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• pp.55-72
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• 2007

We consider the product differentiation model of online channel competition and examine the strategies of hybrid firms in terms of efficiency. After measuring the social cost of online business strategies, we show that (i) online channel of hybrid firm under blockaded entry may increase the social cost if the firms' delivery cost is sufficiently smaller than the consumer's transportation cost, and (ii) online competition under free entry may increase the social cost if the firms' delivery cost is sufficiently larger than the consumer's transportation cost. Finally, we discuss the strategic incentive of hybrid firms to reduce delivery cost and investigate the effect of the Internet maturity on the social cost.

• Management Science and Financial Engineering
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• v.13 no.1
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• pp.25-34
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• 2007

This paper is concerned with proving a conjecture that the two stage assembly system is reversible in deterministic makespan scheduling context. The reversibility means that a job sequence in the assembly system has the same makespan as that of its reverse sequence in the disassembly system which is the reversal of the assembly system. The proposed conjecture shows that the reversibility of serial flowshops can be extended to non-serial and synchronized shops.

• Korean Management Science Review
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• v.33 no.1
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• pp.59-75
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• 2016

The domestic simple payment service was not activated yet compared to foreign countries and there are many things to complement in the legal, institutional, and technical aspects. The future image of the domestic electronic payment propulsion was considered by the scenario planning focusing on the simple payment. Total 6 future scenarios were drawn through the scenario planning, and 3 major strategy directions for attaining the preferred future scenario were drawn. This study drew a meaningful scenario through various analyses and industry specialist questionnaire about the future of the simple payment service which will be a crucial change of the domestic electronic payment under the uncertain future situation, and suggested an implication for the government and every interested party who provides the industrial service to prepare for the future.

• Korean Management Science Review
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• v.24 no.2
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• pp.115-126
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• 2007

Weekly minima of daily log returns of Korean composite stock price index 200 and its five industry-based business divisions over the period from January 1990 to December 2005 are fitted using two block-based extreme distributions: Generalized Extreme Value(GEV) and Generalized Logistic(GLO). Parameters are estimated using the probability weighted moments. Applicability of two distributions is investigated using the Monte Carlo simulation based empirical p-values of Anderson Darling test. Our empirical results indicate that both the GLO and GEV models seem to be comparably applicable to the weekly minima. These findings are against the evidences in Gettinby et al.[7], who claimed that the GEV model was not valid in many cases, and supported the significant superiority of the GLO model.

• Management Science and Financial Engineering
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• v.21 no.1
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• pp.1-9
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• 2015

We consider an m-machine flow shop scheduling problem to minimize the latest completion time, where processing times are uncertain. Processing time uncertainty is described through a finite set of processing time vectors. The objective is to minimize maximum deviation from optimality for all scenarios. Since this problem is known to be NP-hard, we consider it with an ordered property. We discuss optimality properties and develop a pseudo-polynomial time approach for the problem with a fixed number of machines and scenarios. Furthermore, we find two special structures for processing time uncertainty that keep the problem NP-hard, even for two machines and two scenarios. Finally, we investigate a special structure for uncertain processing times that makes the problem polynomially solvable.