• Journal of Korean Society for Quality Management
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• v.31 no.3
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• pp.185-192
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• 2003

In this paper, the properties on the optimal replacement policies for the general failure model are developed. In the general failure model, two types of system failures may occur : one is Type I failure (minor failure) which can be removed by a minimal repair and the other, Type II failure (catastrophic failure) which can be removed only by complete repair. It is assumed that, when the unit fails, Type I failure occurs with probability 1-p and Type II failure occurs with probability p, $0\leqp\leq1$. Under the model, the system is minimally repaired for each Type I failure, and it is repaired completely at the time of the Type II failure or at its age T, whichever occurs first. We further assume that the repair times are non-negligible. It is assumed that the minimal repair times in a renewal cycle consist of a strictly increasing geometric process. Under this model, we study the properties on the optimal replacement policy minimizing the long-run average cost per unit time.

• Journal of Information Technology Services
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• v.8 no.2
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• pp.43-70
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• 2009

As software development and maintenance cost increase quickly, information systems managers are more concerned about how to effectively manage software cost. To estimate the software development cost, most public institutes of Korea use the software cost estimation standard established by the government. Unfortunately, the accuracy of the estimation derived from the standard has not been satisfactory in spite of repetitive modifications made to improve it. One of the major reasons for the inaccuracy is that the standard has too small a number of cost adjustment factors to reflect the various characteristics of a software development project. To remedy this problem, we propose new cost adjustment factors which can be incorporated into the standard and are important to enhance the estimation accuracy, based on the analysis of several well-known software estimation models. Furthermore, by applying the proposed model to real world software projects, we show that the proposed model can produce more accurate estimates than the current standard.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.19 no.40
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• pp.233-240
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• 1996

A fixed amount compensator is proposed for a process with a linear tool wear function. A Cost model is constructed which involve process adjustment cost and quality loss. Symmetric and asymmetric quadratic functions of the deviation of a quality measurement from the nominal target value are considered as the quality loss functions. Methods of finding optimal values of initial setting and compensation limit are presented and a numerical example is given.

• Proceedings of the Safety Management and Science Conference
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• 2011.11a
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• pp.683-694
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• 2011

This study analysed impact of service quality on customer satisfaction and loyalty in the take-out coffee shop. The switching barrier was also studied as a moderating effect. Particularly, this study focused on relationships between customer loyalty and switching barriers. A lot of previous studies interest only in customers satisfaction. This study also analysed relationships among service quality, customer satisfaction, switching barriers and brand loyalty. Eventually, service quality significantly affects customer satisfaction, moderating effects, brand loyalty and marketing performance. SERVQUAL model which was established by PZB (1988) was used as a service quality factors. The impact on customer satisfaction was analysed using multiple regression analysis. Simple regression analysis was used to find effects of customer satisfaction and customer loyalty. Additional factors of switching barriers was classified based on previous studies. Hierarchical multiple regression analysis was used to find factors of customer loyalty among switching barriers. In the result, we can find that the importance of tangibles, responsiveness in service quality factors and contract cost, search cost and continuous cost in moderating effects.

• Journal of Korean Society for Quality Management
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• v.8 no.2
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• pp.45-58
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• 1980

The relationship between the subcontractor and the subcontractor in current industries, especially in the machine manufacturing industry, should be developed to the "Efficient Q-C-D System" in which the three elements of consideration-Quality, Cost and Delivery condition, are in a state of equillibrium. From this point of view the two parts of a subcontract must cooperate in the whole activity: ranging from the initial products planning, through the manufacturing process, to the final usage by customers. In this report, we tried to present Korean machine manufacturing industry with the model of management system of subcontracts in order that machine manufacturers may assure the quality, reduce the production cost and enhance the productivity with the model.

• International conference on construction engineering and project management
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• 2009.05a
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• pp.409-416
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• 2009

This paper presents a tool called Quality-Cost optimization system (QCOS), which integrates Multi-Objective Genetic Algorithm (MOGA) and Quality Function Deployment (QFD), for tradeoff between quality and cost of the unitized metal curtain-wall unit. A construction owner as the external customer pursues to maximize the quality of the curtain-wall unit. However, the contractor as the internal customer pursues to minimize the cost involved in designing, manufacturing and installing the curtain-wall unit. It is crucial for project manager to find the tradeoff point which satisfies the conflicting interests pursued by the both parties. The system would be beneficial to establish a quality plan satisfying the both parties. Survey questionnaires were administered to the construction owner who has an experience of curtain-wall project, the architects who are the independent assessor, and the contractors who were involved in curtain-wall design and installation. The Customer Requirements (CRs) and their importance weights, the relationship between CRs and Technical Attributes (TAs) consisting of a curtain-wall unit, and the cost ratios of each components consisting curtain-wall unit are obtained from the three groups mentioned previously. The data obtained from the surveys were used as the QFD input to compute the Owner Satisfaction (OS) and Contractor Satisfaction (CS). MOGA is applied to optimize resource allocation under limited budget when multi-objectives, OS and CS, are pursued at the same time. The deterministic multi-objective optimization method using MOGA and QFD is extended to stochastic model to better deal with the uncertainties of QFD input and the variability of QFD output. A case study demonstrates the system and verifies the system conformance.

• Proceedings of the Safety Management and Science Conference
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• 2011.04a
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• pp.731-746
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• 2011

The successful and sustainable growth of SMEs depends on their ability of strengthen their competitiveness in quality and cost and service more than anything else as a fundamental of operation. Among these key competitive factors of SMEs, quality is the most critical factor in manufacturing business fields. Because quality strongly influence cost and service performance on this manufacturing business field. There are many different ways to improve the quality performance but it needs proper management decision to choose the best way what can maximize outputs with minimum inputs. And it needs effective measurement methods and some indicators to analysis the quality performance properly. The quality cost is one of the simplest key indicators to measure the quality performance and the effectiveness of quality related management decisions. The major purpose of this study is to diagnose the categorized current level of actual quality cost of local SMEs to maximize their quality management effectiveness through comparing their level with others what's expressed in early studies. In this study, through survey on local SMEs, we found that their average annual quality cost ratio versus turnover - Total amount of annual quality cost divided by annual turnover - is around 3.69% excluded some SME's performances what have different quality control measures with others. And we found some results what corresponded with the early studies on the correlations between those categorized quality costs factors and some discrepancies between some of the literature model and the early case study results as follows. There were negative correlations between the Prevention costs and the External failure costs, and the Appraisal costs and the External failure costs, and there was positive correlation between the Appraisal costs and Internal failure costs same as early studies. But, we couldn't found any strong negative correlations between the Cost of control - Preventive costs & Appraisal costs - and the Cost of Failure of control - Internal & External failure costs -. It reveals not only the lack of effectiveness on their preventive or appraisal activities but also it can reveal there were so many effective ways to prevent the failure costs properly such as some innovative investment on Factory automation includes Error Proofing and more preventive actions to improve the effectiveness of the typical management methods likes CE (Concurrent Engineering), APQP (Advanced Product Quality Planning), FMEA (Failure Mode & Effect Analysis) etc.

• Proceedings of the Korean Society for Quality Management Conference
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• 2006.11a
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• pp.294-301
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• 2006

This study attempts to investigate a general service sector model which aims to describe the extent to which customer repurchase intention is influenced by customer satisfaction, Customer loyalty, switching cost. This study attempts to investigate different group. Brand group 1 is higher Brand loyalty than Brand group 2. Brand Group 1 is 276 and Brand Group 2 is 271 consumers in service sector that they were used into data analysis. The data were analyzed by factor analysis and Structural Equation Model using SPSS and AMOS program. The results show that nearly all of the hypothesized relationships construct are supported. First, the direct effects of customer satisfaction on customer loyalty and switching cost were confirmed. The service company not only strengthens customer loyalty, but also strategically makes the most use of switching cost to satisfy customer satisfaction and create sustainable company advantages. Second, the interactive relationships among switching cost and customer loyalty were very significant. The proper management of these mediating variables plays key roles in connecting customer satisfaction with repurchase intention. Third, the effects of customer loyalty and brand preference on repurchase intention were supported but switching cost rejected in the path analysis. Implications of the results for path analysis are discussed and future research directions are offered.

• Proceedings of the Korean Society for Quality Management Conference
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• 2006.04a
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• pp.120-125
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• 2006

This study attempts to investigate a general service sector model which aims to describe the extent to which customer repurchase intention is influenced by customer satisfaction, customer loyalty, switching cost. 195 consumers in service sector were used into data analysis. The data were analyzed by factor analysis and Structural Equation Model using SPSS and AMOS program. The results show that nearly all of the hypothesized relationships construct are supported. First, the direct effects of customer satisfaction on customer loyalty and switching cost were com firmed. The service company not only strengthens customer loyalty, but also strategically makes the most use of switching cost to satisfy customer satisfaction and create sustainable company advantages. Second, the interactive relationships among switching cost and customer loyalty were very significant. The proper management of these mediating variables plays key roles in connecting customer satisfaction with repurchase intention. Third, the effects of customer loyalty and brand preference on repurchase intention were supported but switching cost rejected in the path analysis. Implications of the results for path analysis are discussed and future research directions are offered.

• Journal of Nutrition and Health
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• v.36 no.5
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• pp.515-527
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• 2003

Objectives： A meta-analysis of the literatures was conducted to evaluate the cost-effectiveness of medical nutrition therapy by dietitians. Methods : The 30 studies were identified from a computerized search of published research on MEDLINE, Science-Direct and the PQD database until May, 2002 and a review of reference lists. The main search terms were“dietitian”,“dietary intervention”,“nutrition intervention”, “cost”,“cost-effectiveness”and“cost-benefit analysis”. The subgroup analysis was performed by publication year, study design, intervention provider, type of patient (in/out-patient) and type of cost (total cost/direct cost). Two reviewers independently selected trials for inclusion, assessed the quality and extracted the data. Results : The 30 studies were identified using the electric database search and bibliographies. The 17 trials were eligible for inclusion criteria, then the systematic review and a meta-analysis were conducted on effectiveness and cost-effectiveness of medical nutrition therapy. The quality of the studies was evaluated using the quality assessment tool for observational studies. The quality score was 0.515 $\pm$ 0.121 (range : 0.279-0.711, median : 0.466). The meta-analysis of 17 studies based on the random effect model showed that medical nutrition therapy was highly effective in treating the diseases (effect size 0.3092 : 95% confidence interval 0.2282-0.3303). The vote-counting method, one of meta-analysis methods, was applied to evaluate the cost-effectiveness of medical nutrition therapy conducted by dietitians. Two criteria (method 1, method 2) for voting were used. The calculated p-values for method 1 (more conservative method) and method 2 (less conservative method) were 0.1250 and 0.0106, respectively. Medical nutrition therapy by dietitians was significantly cost-effective in the method 2. Conclusion. This meta-analysis showed that the effectiveness of medical nutrition therapy was statistically significant in treating disease (effect size 0.3092), and that the cost-effectiveness of medical nutrition therapy was statistically significant in the method 2 (less conservative method) of vote counting. (Korean J Nutrition 36(5): 515~527, 2003)