• Journal of Korean Institute of Industrial Engineers
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• v.33 no.1
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• pp.26-32
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• 2007

This study deals with waiting-time dependent backordering rate during stock-out period in the EconomicProduction Quantity (EPQ) model. Assuming that the backordering rate follows an exponentially decreasingfunction of the waiting time, the backorder rate is developed under First-Come-First-Served (FCFS) andLast-Come-First-Served (LCFS) Policy. The mathematical models are developed based on differential equations.Through numerical examples, the validity of the developed models is illustrated.

• Proceedings of the KSR Conference
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• 2011.05a
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• pp.775-789
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• 2011

Centering on KTX stations, Korea is implementing specialized development of metropolitan business zones nationwide and is in the process of building the transfer link system of transportation in order to actualize intermodalism nationwide. Daejeon station, hub of high-speed railway requires the effective transportation transfer system considering Daejeon station area reorganization plan and opening of second phase high-speed railway. Based on the analysis of the possibility and validity of building a transit center under the Transportation System Efficiency Act, it is necessary to make a mutual benefit in a regional development by installing the resonable transfer system between railway and other transportation services. Through analysis of current situations and technical, economic and environmental feasibility evaluation, design plan of effective transportation transfer system in Daejeon station is proposed.

• Proceedings of the KSR Conference
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• 2011.05a
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• pp.1582-1590
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• 2011

An analysis of the railroad industry for R&D investments has been insufficient whereas there are lots of analysis of accumulation of technology, economic performances and ripple effects for macroscopic view and other industry of R&D investments. This study decided intellectual rights, patent, and paper as common indicators of scientific and technological performances for setting up performance targets through surveying and analysis of preceding study and verified a appropriateness of scientific and technological performances for railroad R&D 11 projects which were successfully finished. Preceding study has been set up performance targets by research investments as input, but this study made a performance target by model through a cross-sectional and residual analysis of performances of railroad R&D 11 Projects in applying research investments, capital investments, inner labor cost and inner labor cost per man and research time as inputs, and verified a validity and a empirical analysis through analysis of other project.

• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.1407-1410
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• 1997

Advanced sensor design and filtering technology have been studied to obtain information for condition monitoring and diagnostics inmachining processes. To develope and economic monitoring system in end milling processes, indirect and reliable type of cutting force estimators were required. In this paper, an estimation method of cutting forces during end milling processes was studied through the measurement of current signals obtained from spindle and feeddrive motors. Cutting force and torque models were derived from the cutting geometry in down milling processes. Relationships between motor currents and cutting forces were also developed in the form of AC and DC components from the developed force models. The validity of the cutting force estimator was confirmed by the experiments under various cutting conditions.

• Culinary science and hospitality research
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• v.20 no.5
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• pp.93-100
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• 2014

This study performed to identify the relationships among experiential value, brand image, satisfaction and customer loyalty in context of full-service restaurant, and to find the moderating effect of gender on the formulated model. SPSS 18.0 and AMOS 18.0 were employed to conduct frequency analysis, reliability analysis, exploratory and confirmatory factor analysis, and multigroup analysis to examine moderating effect. Results confirmed the validity and reliability and found significant relationships among the constructs. First, two factors of experiential value (e.g., aesthetic and economic value) have positive influence on brand image, satisfaction, and brand image was significant predictor of customer satisfaction. Second, satisfaction was significant antecedent of attitudinal loyalty and the attitudinal loyalty has influence on behavioral loyalty. In addition, current study identified moderating effect of gender between playfulness and brand image even though there was on significant relationship between both constructs. These results will be meaningful for developing marketing strategies and successful business especially for full-service restaurants.

• Journal of Information Technology Services
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• v.18 no.5
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• pp.193-207
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• 2019

In recent years, Digital Social Innovation has been emerging at home and abroad and new solutions are being proposed by the perspective of User using digital technology in order to solve social and economic problems of the city. In addition, Living Labs which is an innovative tools and space enable to solve problems doing activities with various participants led by users. Therefore, this study aims to systematically manage the activities of Living Lab in Digital Social Innovation and improves the Living Lab sustainability using the performance indicators which are going to be developed. Furthermore, construct the appropriate indicator of each project process and take test at real Living Labs. As a result, performance indicator was derived from each procedure in the Living Lab project, and proved validity and reliability of the indicators through qualitative and quantitative methods by interviews and the questionnaire from the participants of Living Labs.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.27 no.1
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• pp.74-78
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• 2004

Systems are often operated by not integration but blocking, i.e., non-standardization. The system blocking is mainly caused by non-standardization or incompatibility. The integrated system is effective, but researches for quantification of effectiveness from Integrating system are few. System blocking causes additional cost which is almost intangible and potential. In this paper we proposed a model to quantify the effectiveness of system integration. To verify the validity of proposed model, we applied the model for Korean information and communication industry and forecasted the cost of integration for South and North Korean telecommunication industry in the way of three scenarios.

• KCI Concrete Journal
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• v.13 no.2
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• pp.26-32
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• 2001

A simple expected damage cost model is developed and a systematic approach to evaluate the economic effects of seismic hazards to reinforced concrete structures is presented. An expected damage cost function during a specific lifetime is modeled by a Poisson's process with uniform continuous cash flow assumption. It is possible that the proposed method can decouple the damage cost effect from random earthquake events. Thus, expected damage cost function can be formulated as a combination of three independent terms; a present worth factor of Poisson's process, a damage cost interpolation function and a mean occurrence rate of earthquake intensity. The validity of the proposed method is demonstrated by a comparative study of LCC evaluations with the previous study.

• The Journal of Fisheries Business Administration
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• v.38 no.1 s.73
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• pp.19-45
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• 2007

There have not been many studies which considered both quantitative and qualitative location factors on the issues of site selection problems for a fish farm. This study develops AHP(analytic hierarchy process) model to resolve site selection problem for a fish raising farm by using quantitative and qualitative factors. In order to evaluate the validity of the location factors found in the literature review, the study used advice from fish raising farmers and related academic experts. Four major factors have been selected as economic factors, social factors, natural environmental factors and infrastructures. An AHP structural diagram has developed by considering the factors and potential sites proposed for fish farming. Through the survey on the preference of factors and potential sites, pairwise comparison matrices have been estimated and used to calculated the relative weights of each potential site. The AHP model process shown in the study can be applied to resolve site selection problems for fish raising farmers.

• 한국신재생에너지학회:학술대회논문집
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• 2005.06a
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• pp.51-54
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• 2005

Generator efficiency optimization is important for economic saving and environmental pollution reduction. In general, the machine loss can be reduced by the decreasing the flux level, resulting in the significant reduction of the core loss. This paper proposesan model-based controller is used to decrement the excitation current component on the basis of measured stator current and machine parameters and the q-axis current component controls the generator torque, by which the speed of the induction generator iscontrolled according to the variation of the wind speed in order to produce the maximum output power. The generator reference speed is adjusted according to the optimum tip-speed ratio. The generated power flows into the utility grid through the back-to-back PWM converter. The grid-side converter controls the dc link voltage and the line-side power factor by the q-axis and the d-axis current control, respectively. Experimental results are shown to verify the validity of the proposed scheme.