• Journal of Korean Society for Quality Management
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• v.17 no.1
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• pp.116-124
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• 1989

A multi-period production-inventory scheduling model, which extends the customary dynamic lot sizing model to the one for deteriorating items, is developed. The amount of deterioration during a period is assumed to be proportional to the on-hand inventory at the end of the period. It is futher assumed that the deterioration rates vary from period to period. In addtion, an expediting cost due to the delay of outstanding order is included and it is allowed to offset the order release date in advance, instead, in order to avoid incurring the cost. Finally, a quasi-WW algorithm corresponding to the Wagar-Whitin algorithm is proposed to obtain the optimal production-inventory schedules.

• Proceedings of the Korean Society for Quality Management Conference
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• 2006.04a
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• pp.400-404
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• 2006

The environmental problem come because the demage cost of environmental pollution is not properly reflected in market price. The government regulations for market is justified to solve the problem. The policy needs a close analysis of environmental, economical effect for the point of time, methods, rational decision making of the government regulations. Especially, we need to assume and analyze about social expenses by environmental pollution and policy execution. The cost-benefit analysis about environmental pollution is used to support decision making. The value of benefit about damage by environmental pollution or about improvement changes a monetary unit through the cost-benefit analysis. The working like this is said environmental material valuation or measuring valuation. This work is studied about looking for proper analysis model to apply our environmental materials.

• Industrial Engineering and Management Systems
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• v.13 no.2
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• pp.231-249
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• 2014

This paper discusses a green supply chain with a manufacturer and a collection trader, and it proposes an optimal production planning for remanufacturing of parts in used products with quality classification errors made by the collection trader. When a manufacturer accepts an order for parts from a retailer and procures used products from a collection trader, the collection trader might have some quality classification errors due to the lack of equipment or expert knowledge regarding quality classification. After procurement of used products, the manufacturer inspects if there are any classification errors. If errors are detected, the manufacturer reclassifies the misclassified (overestimated) used products at a cost. Accordingly, the manufacturer decides to remanufacture from the higher-quality used products based on a remanufacturing ratio or produce parts from new materials. This paper develops a mathematical model to find how quality classification errors affect the optimal decisions for a lower limit of procurement quality of used products and a remanufacturing ratio under the lower limit and the expected profit of the manufacturer. Numerical analysis investigates how quality of used products, the reclassification cost and the remanufacturing cost of used products affect the optimal production planning and the expected profit of a manufacturer.

• Journal of Korean Society for Atmospheric Environment
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• v.27 no.6
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• pp.805-818
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• 2011

The unequivocal risk of climate change, the weakness of energy security, and the problem of air quality will be possibly accelerated by the same reason, the enhanced fossil fuel dependancy in the future. It is obvious that greenhouse gases and air pollutants are mainly emitted from same sources. Moreover, greenhouse gases and air pollutants have their adversed impacts on same socio-economical, and environmental sectors. With these regards, several but limited studies have emphasized on the importance of the integrated management of climate change and air quality problem. In this study, we address the current trend of energy consumption and the change of air quality condition. Also the related policies are checked out in order to reduce emissions of greenhouse gases and air pollutants in Korea. By surveying previous studies, it is shown that the cost of climate change actions can be reduced by air quality co-benefits and vis-a-versa. Also the integrated strategy for climate change and air quality is introduced in term of cost-effectiveness and co-benefit.

• International conference on construction engineering and project management
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• 2024.07a
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• pp.738-744
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• 2024

Cost measurement plays the fundamental role within the modern construction and project management models, where not only materials, labors and services are measured by cost but also programme delays, quality defects and project risks are converted to be measured as cost. However, the problems of cost measurement models have been analyzed only from the aspect of owners and contractors who construct the buildings, not from the aspect of users who use buildings. In this article, analysis of data surrounding the current high inflation of construction costs in England is conducted, to find out its route causes within the current and historical development of construction cost measurement models. The conclusion is that current cost measurement models are based on the aspect of owners and contractors, which is to assess buildings as monetary asset for short-term taxation purpose, without due regard how buildings are used by users for long-term. Alternative cost measurement models based on the aspect of users are proposed, which assess buildings as functional asset for its long life-cycle. Pros and cons of these two adverse models are discussed in details, and harmonization between owners, contractors and users are sought, in order to arrive at a more consistent cost measurement approach which can be equally applied to buildings and built-environment by all stakeholders involved.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.42 no.3
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• pp.80-88
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• 2019

Recently, automobile manufacturing companies, which are major customers of them, are requiring IATF 16949 (ISO/TS 16949) certification as a mandatory requirement to secure product quality. In particular, IATF 16949 : 2016, revised in October 2016, was reinforced product traceability requirements for production information management by lot in the production process. Therefore, small and medium-sized precision parts processing companies in the automobile industry are very difficult to survive due to quality and price competition for customers satisfaction. MES (Manufacturing Execution System) is required to solve this problem. However, small and medium sized precision parts processing enterprises are reluctant to introduce the MES which is not suitable for the manufacturing environment of them such as high cost and low utilization. Even if the system is introduced, it is difficult to operate and maintain the system because the lack of computer manpower. In this paper, we propose a method for building a lot tracking system for small and medium precision parts processing companies by reviewing relevant literature and analyzing cases. In addition, by managing the production history for each lot of the final product in the system, we will grasp the effect of reducing the quality failure cost obtained by minimizing the range of defect selection.

• Journal of Korean Society for Quality Management
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• v.11 no.2
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• pp.25-31
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• 1983

Often arrangement for effective product assessment and audit have not been completely satisfactory. The underlying reasons are: (a) The lack of early evidence of new unit quality. (b) The collection and processing of data. (c) Ineffective data analysis techniques. (d) The variability of information on which decision making is based. Because of the nature of the product the essential outputs from an affective QA organization would be: (a) Confirmation of new unit quality. (b) Detection of failures which are either epidemic or slowly degradatory. (c) Identification of failure cases. (d) Provision of management information at the right time to effect the necessary corrective action. The heart of an effective QA scheme is the acquisition and processing of data. With the advent of data processing for quality monitoring becomes feasible in an automotive testing environment. This paper shows how the method enables us to use Automotive Testing data for the cost benefits of QA management.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.40 no.2
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• pp.129-136
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• 2017

Among the information technology and automation that have rapidly developed in the manufacturing industries recently, tens of thousands of quality variables are estimated and categorized in database every day. The former existing statistical methods, or variable selection and interpretation by experts, place limits on proper judgment. Accordingly, various data mining methods, including decision tree analysis, have been developed in recent years. Cart and C5.0 are representative algorithms for decision tree analysis, but these algorithms have limits in defining the tolerance of continuous explanatory variables. Also, target variables are restricted by the information that indicates only the quality of the products like the rate of defective products. Therefore it is essential to develop an algorithm that improves upon Cart and C5.0 and allows access to new quality information such as loss cost. In this study, a new algorithm was developed not only to find the major variables which minimize the target variable, loss cost, but also to overcome the limits of Cart and C5.0. The new algorithm is one that defines tolerance of variables systematically by adopting 3 categories of the continuous explanatory variables. The characteristics of larger-the-better was presumed in the environment of programming R to compare the performance among the new algorithm and existing ones, and 10 simulations were performed with 1,000 data sets for each variable. The performance of the new algorithm was verified through a mean test of loss cost. As a result of the verification show, the new algorithm found that the tolerance of continuous explanatory variables lowered loss cost more than existing ones in the larger is better characteristics. In a conclusion, the new algorithm could be used to find the tolerance of continuous explanatory variables to minimize the loss in the process taking into account the loss cost of the products.

• Journal of Korean Society for Quality Management
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• v.30 no.3
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• pp.150-167
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• 2002

Normative theory suggests that control systems should be designed to complement management's objectives and strategies. However, few empirical studies have focused on how control systems have been modified to complement new manufacturing techniques, such as zero-defect strategy. The major purpose of this study is to examine the effects of the attributes of quality strategy and control system on performance. The previous studies have subdivided quality strategy into the ECL(economic conformance level) and ZD(zero-defect) strategy. To accomplish the purpose, this study empirically analysed the data based on the questionnaires from manufacturing department personnel of 67 Korean companies. The major results are as follows. The companies that had implemented the ZD strategy and its control system outperformed the companies that had implemented ECL strategy. Also, the ZD strategy differs from ECL strategy in control system, the criteria of performance evaluation and feedback frequence variable. There is no difference in quality performance monitoring and communication variable. From this results, although many companies have strived for continuous improvement of quality, it was restricted in improvement activities that dont's required much investment cost, quality performance monitoring and communication.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• autumn
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• pp.286-289
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• 2003

In turn-key projects, escalation of cost by design errors is not allowed because a contractor prepares the design. Therefore, cost escalation by design errors results in increasing the cost of the prime contractor. The rate of profit decreases finally. In addition, design errors bring not only schedule delay but also serious quality problem by unknown errors. This study tries to dissolve problems, that of cost increase. process delay and a falling-off in quality by investigating cause of design errors and presenting a scheme for reducing design errors.