• Journal of the Korean Statistical Society
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• v.23 no.2
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• pp.403-420
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• 1994

An economic design of the $\bar{X}-R$ chart using variable sample size (VSS) scheme is proposed in this paper. In this design the sample size at each sampling time changes according to the values of the previous two sample statistics, sample mean and range. The VSS scheme uses large sample if the sample statistics appear near inside the control limits and smaller sample otherwise. The set of process parameters, such as the sampling interval, control limits and the sample sizes, are chosen to minimize the expected cost per hour. The efficiency of the VSS scheme is compared to the fixed sample size one for cases where there is multiple of assignable causes. Percent reductions of the expected cost in the VSS design are calculated for some given sets of cost parameters. It is shown that the VSS scheme improves the confidence of the procedure and performs statistically better in terms of the number of false alarms and the average time to signal, respectively.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.32A no.10
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• pp.81-92
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• 1995

In this paper, we present a high-level synthesis system that generates area-efficient RT-level datapaths with multiport memories. The proposed scheduling algorithm assigns an operation to a specific control step such that maximal sharing of functional units can be achieved with minimal number of memory ports, while satisfying given constraints. We propose a measure of multiport memory cost, MAV (Multiple Access Variable) which is defined as a variable accessed at several control steps , and overall memory cost is reduced by equally distributing the MAVs throughout all the control steps. Experimental results show the effectiveness of the proposed algorithm. When compared with previous approaches for several benchmarks available from literature, the proposed algorithm generates the datapaths with less memory modules and interconnection structures by reflecting the memory cost in the scheduling process.

• Journal of Distribution Science
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• v.10 no.11
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• pp.79-88
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• 2012

Purpose - The objective of this paper is to suggest that a company's CRM activities have an effect on customer loyalty in the Korean retail industry. Typically, Korean customers use large local marts with convenience in the absence of any other choice. Therefore, this study aims to shed light on the fact that customers do not break away from their preferred retail stores, either owing to their stringent loyalty (the lie loyalty) or difficulty in turning to alternative choices. Research design, data, methodology - By surveying a sample of 200 hyper-markets through a questionnaire, and excluding dubious and missing responses, I obtained 181 samples to be included in the empirical analysis. The survey was conducted for two weeks during October 2011. AMOS and SPSS18 statistical packages were used for conducting statistical analysis for this study. This paper was developed using the concept of customer equity on CRM, which is known to have a positive impact on customer loyalty through the satisfaction and switching-barrier parameters. The hypothesis of this paper is that customer equity is composed of relationship equity, value equity and brand equity, and that the relationship equity variable has positive effects on the value equity and brand equity amongst other types of customer equity. Moreover, customer equity influences customer loyalty through parameters including customer satisfaction and switching costs in the Korean retail industry. Results - According to the results of the analysis, it was confirmed that relationship value had a positive effect (+) on all variables, including the perceived QoS (Quality of Service), store brand images, economic value, and store convenience. It was also confirmed that the assumption that the perceived QoS (Quality of Service), economic value, and store convenience had a positive effect on customer satisfaction was shown to be statistically significant, with a p-value below 0.05. Only the store brand value variable had an effect on the switching-cost variable with respect to the causal sequence of the variables, including the perceived QoS, store brand value, economic value, and store convenience. The remaining variables did not seem to influence the switching-cost variable. On the other hand, another effect showed that customer satisfaction had a statistically significant influence on the switching-costs variable. Moreover, the customer satisfaction and switching-cost variables also had a statistical influence on customer loyalty. Conclusions - The CRM activities had an influence on various variables (including perceived QoS, perceived economic value, store brand value, and store convenience) pertaining to customer values. Customer satisfaction and switching-cost had some effects on customer loyalty as a parameter. This confirms that stringent loyalty exists with respect to customer loyalty in the retail industry. The fact that the variable had such a statistically significant influence on the switching-cost and store brand equity variables means that consumers react to the reputation of a brand, confidence about the store, and quality confidence. The implications of this study in the retail industry should be further extended to devise strategies for customer retention.

• Journal of Korean Academy of Nursing Administration
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• v.10 no.1
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• pp.1-9
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• 2004

Korean health insurance has adopted preliminary DRG payment system through 8 DRGs from 1997. But present DRG payment system gives economic incentives for hospitals to hire less nurse. This study was attempted to develope DRG adjust index to differentiate DRG price by nurse staffing level for nursing care quality. Method: We analyzed inpatient care cost by medical institute and developed DRG adjust index to differentiate DRG price by nurse staffing level. Results: Among same medical institute, inpatient care cost are very different according to hospital's nurse staffing level. In the case of casarean section, inpatient care cost of the 1st grade general hospital are more expensive 85,732won than the 6th grade hospital. The cost difference are 8.24% of total casarean section DRG price and 16.48% of DTG variable price. We developed DRG adjust index-a to apply DRG variable price and index-b to apply DRG total price for compensation cost difference of hospitals. Conclusions: DRG price adjust index will give economic incentive for hospitals to hire more nurse and improve nursing care quality.

• 제어로봇시스템학회:학술대회논문집
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• 1986.10a
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• pp.367-369
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• 1986

Guaranteed cost control is a method applicable to a class of systems with uncertain parameters that guarantees an upper bound of the cost functional. This paper is concerned with a matrix decomposition technique used to yield a reasonable upper bound of the cost functional for a finite-time LQ regulator problem. The uncertain linear systems dealt with in this paper are described by a set of state equations of single-input phase-variable canonical form which contain unknown but bounded uncertain parameters.

• Journal of Korean Institute of Industrial Engineers
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• v.19 no.1
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• pp.73-77
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• 1993

This paper considers an Economic Order Quantity Model under random life cycle. It is assumed that the life cycle of the product is unknown; a random variable. Three cost parameters are considered; ordering cost, inventory carrying cost and salvage cost. Expected total cost is the optimization criterion. We show that the optimal cycle length is unique and finite, and present a simple line search method to find an optimal cycle length.

• Journal of Korean Society for Quality Management
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• v.36 no.4
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• pp.77-86
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• 2008

Due to the rapid growth in automated testing and manufacturing systems, screening inspection becomes very attractive. In this paper, we investigate the effects of limited capacity on screening inspection using a surrogate variable. The model is developed under the assumption that the reprocessed and nonreprocessed items are produced by the same manufacturing process and therefore their quality characteristics are independently and identically distributed. Profit models are constructed which involve four price/cost components; selling price, cost incurred by imperfect quality, reprocessing and quality inspection costs. Methods of finding the optimal screening limits are presented, and a numerical example is given. Sensitivity analyses are also performed to study the effect of a process standard deviation on this model.

• Korean Journal of Computational Design and Engineering
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• v.8 no.4
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• pp.212-221
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• 2003

In order to reduce the lead-time and cost, the technology of rapid prototyping (RP) has been widely used. A new rapid prototyping process, transfer-type variable lamination manufacturing process by using expandable polystyrene foam (VLM-ST), has been developed to reduce building time, apparatus cost and additional post-processing. At the same time, VLM Slicer, the CAD/CAM software for VLM-ST has been developed. In this study, algorithms for accuracy improvement of VLM-ST, which include offset and overrun of a cutting path and generation of a reference shape are developed. Offset algorithm improves cutting accuracy, overrun algorithm enables the VLM-ST process to make a shape of sharp edge and reference shape generation algorithm adds additional shape which makes off-line lamination easier. In addition, proposed algorithms are applied to practical CAD models for verification.

• IE interfaces
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• v.20 no.2
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• pp.103-111
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• 2007

A heterogeneous VRP which considers various capacities, fixed and variable costs was suggested in this study. The transportation cost for vehicle is composed of its fixed and variable costs incurred proportionately to the travel distance. The main objective is to minimize the total sum of transportation costs. A mathematical programming model was suggested for this purpose and it gives an optimal solution by using OPL-STUDIO (ILOG CPLEX). A genetic algorithm which considers improvement of an initial solution, new fitness function with weighted cost and distance rates, and flexible mutation rate for escaping local solution was also suggested. The suggested algorithm was compared with the results of a tabu search and sweeping method by Taillard and Lee, respectively. The suggested algorithm gives better solutions rather than existing algorithms.

• Asian Journal of Innovation and Policy
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• v.12 no.1
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• pp.101-130
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• 2023

The increasing cost, and demand for, household energy has increased attention to the phenomena of energy burdens. Despite this increased attention, a lack of consensus remains in pinpointing the strongest predictors, and geographic differences, that exist within the energy ecosystem. This study addresses this gap by utilizing a series of dummy variable regressions across cities, suburbs, and rural areas within Erie County, New York-a county noted to have particularly high energy burdens. Specifically, three types of predictor sets were incorporated into the methodology: a set of socioeconomic variables, physical variables, and a combination of both variable sets. The results of this study suggest that cities tend to have the highest electricity burdens. Despite the aging infrastructure in Erie County, high energy burdens were driven primarily by socioeconomic factors such as housing cost burden and poverty status. Lastly, this study explores various planning and policy implications Erie County can utilize to reduce energy burdens. In turn, this study highlights the importance of focusing policy efforts on existing social service programs to provide support to the region's neediest households.