• Proceedings of the Safety Management and Science Conference
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• 2008.04a
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• pp.283-293
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• 2008

Analysis of Means(ANOM) is a visualization tool for comparing several means to the grand mean like control chart type. This paper reviews five ANOM methods for continuous data such as ANOM, ANOME (ANOM for Treatment Effects), ANCON (Analysis of Contrasts), ANOMV (ANOM for Variance), ANOMC (ANOM for Correaltion). Three ANOM tools for discrete data such as ANOMNP (ANOM for Nonconforming Proportions), ANOMNC (ANOM for Nonconforming Unit), ANOMNPU (ANOM for Nonconfirmities Per Unit) are also developed.

• Journal of the Korea Safety Management & Science
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• v.11 no.1
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• pp.131-136
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• 2009

The research develops the calculation steps of Z sigma level, process capability index(PCI) and process performance index(PPI) applicable to the discrete process in the service industry. The paper presents three following topics used related process indexes according to the precision and accuray in the continuous process. The contents include diverse process indexs for nonconformities by SPC attribute control charts and bias coefficient. The same technique of the nonconformites is also used in the nonconforming units. The practical examples are provided to help easier understanding for users.

• Journal of Korean Society for Quality Management
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• v.23 no.3
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• pp.140-155
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• 1995

This paper proposes a quality control method of assembly parts based on parts inspection information. We use the parts inspection information for reduction of defective fraction in assembly and prediction of assembly quality. At first, we build the functional relationship between parts and assembled unit by regression analysis. Secondly, if we use the inspection informations of parts which are estimators of means and variances, we can predict the nonconforming probability of assembled unit and propose the best assembly method. In a case study, we showed the efficency of the proposed method in two part assembly.

• Management Science and Financial Engineering
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• v.16 no.1
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• pp.119-135
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• 2010

In this paper, we readdress the optimization problem for minimizing the inspection cost in a back-light unit inspection system, which forms a network including a K-stage inspection system, a source inspection shop, and a re-inspection shop. In order to formulate our objective function when the system is in a steady state, assuming that the number of nonconforming items in a lot follows a binomial distribution when a lot is formed for inspection, we make a steady-state network flow analysis between shops, and derive the steady-state amount of flows between nodes and the steady-state fraction defectives by solving a nonlinear balance equation. Finally we provide some fundamental properties and an enumeration method for determining an optimal value of K which minimizes our objective function. In addition, we compare our results numerically with previous ones.

• Journal of Korean Institute of Industrial Engineers
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• v.24 no.3
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• pp.359-365
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• 1998

An economic process monitoring procedure is presented when the major quality characteristic of the item is dichotomous. Every item is inspected and decided whether it is conforming or not. If an item is found to be nonconforming, the previous number of the successive conforming items is compared with a predetermined number r to check the process for existence of any assignable cause of variation. A cost model is constructed on the basis of costs of inspection, illegal signal, undetected out-of-control state and corrective action. By minimizing the expected total cost per unit time, the optimal value of r is obtained. The effects of cost coefficients are studied numerically.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.40 no.1
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• pp.165-172
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• 2017

Machines are physically or chemically degenerated by continuous usage. One of the results of this degeneration is the process mean shift. Under the process mean shift, production cost, failure cost and quality loss function cost are increasing continuously. Therefore a periodic preventive resetting the process is necessary. We suppose that the wear level is observable. In this case, process mean shift problem has similar characteristics to the maintenance policy model. In the previous studies, process mean shift problem has been studied in several fields such as 'Tool wear limit', 'Canning Process' and 'Quality Loss Function' separately or partially integrated form. This paper proposes an integrated cost model which involves production cost by the material, failure cost by the nonconforming items, quality loss function cost by the deviation between the quality characteristics from the target value and resetting the process cost. We expand this process mean shift problem a little more by dealing the process variance as a function, not a constant value. We suggested a multiplier function model to the process variance according to the analysis result with practical data. We adopted two-side specification to our model. The initial process mean is generally set somewhat above the lower specification. The objective function is total integrated costs per unit wear and independent variables are wear limit and initial setting process mean. The optimum is derived from numerical analysis because the integral form of the objective function is not possible. A numerical example is presented.