• Korean Management Science Review
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• v.33 no.3
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• pp.89-103
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• 2016

In this paper, we design sampling inspections and service capacities simultaneously for multi-products. Products are supplied in batches after rectifying inspections, that is, rejected lot is subject to total inspection and defective products are reworked to good ones. When supplied, all defective products are uncovered and returned to service. Particularly, we extend Kim [1] by introducing the fixed costs of providing services and show that the cost function of a product is no longer linear or convex in terms of the level of service provision. We develop a framework for a product to deal with this joint design problem and a dynamic programming algorithm for multi-products which allocates the given number of the total service capacities among products with the considerably smaller computations than the total number of possible allocations.

• Journal of Korean Society for Quality Management
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• v.7 no.2
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• pp.17-21
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• 1979

There are many kinds of the mathematical models which are developed for choosing the economic inspection plan. The aim of this paper is to classify these mathematical models, and to examine their characteristics. The mathematical models for choosing the economic inspection plan can be classified into three groups. The first of it is the break-even analysis, the second group of the model is to choose the inspection plan so as to minimize total sampling inspection cost function, and the third group of it is the model to choose the inspection plan which maximize the profit function of the sampling inspection. As a result of examining the characteristics of this classified group of the models the model to choose the inspection plan which minimize total sampling inspection cost is more economical than the other models.

• Journal of Korean Society for Quality Management
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• v.27 no.3
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• pp.113-124
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• 1999

Inspection policies deal with stochastically failing systems in which failures cannot be detected without inspection. In this paper, we considered an effective inspection policy to detect system failure under imperfect inspection. Approximate total expected cost is derived and a simple algorithm to determine inspection schedule is Presented. Numerical examples showed that the inspection policy is easily applicable and cost effective.

• Journal of the Korean Operations Research and Management Science Society
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• v.28 no.3
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• pp.49-60
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• 2003

In this paper, we study the joint design of sampling inspections and service capacities for multi-products. Products of different defect rates which are either deterministic or random variables are supplied in batches after sampling inspection and rework. When supplied, all defective products that have not been inspected in batches are uncovered through total inspection and returned to service. We identify the optimal inspection policies and service capacities for multi-products reflecting the relationships between inspection rework costs and service provision costs. We also develope a marginal allocation algorithm for the optimal allocation of the limited total service capacity to products as well as inspection quantities.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.21 no.45
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• pp.201-213
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• 1998

We address the problem of choosing the most economic mean value for an automatic filling operation on a production line through the sampling inspection. If quality characteristic of a unit is less than inspection specification then the goods is not accepted. Otherwise, it is accepted. The lots that the numbers of non-conforming units in a sample are larger than the allowable number of non-conforming units are rejected. The non-conforming units in the rejected lots are separated by the screening inspection. The non-conforming units separated are sold in discount price. We assume that quality characteristic is larger-the-better characteristic, the distribution of quality characteristic is normal distribution, and the standard deviation of the distribution is known. This paper presents total expected profit function model considering sales revenue, inspection costs, and material costs. The manufacturing process mean value maximizing total expected profit is determined, and the results of the process target value and total expected profit is analyzed as coefficients change.

• Journal of Korean Institute of Industrial Engineers
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• v.35 no.3
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• pp.194-202
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• 2009

In this paper, we address an optimization problem and a case study for minimizing the cost of inspections incurred throughout an inspection system, which includes a K-stage inspection system, a source inspection shop, and a re-inspection shop. In order to formulate the inspection cost function, we make a time-based flow analysis between nodes (or shops), and derive the limiting sizes of flows between nodes and limiting defective rates by solving a set of nonlinear balance equations. It turns out that the number of items reworked throughout the inspection system is invariant irrespective of the defective rate of items moved through the K-stage inspection system. Hence we define the inspection cost as the total number of items inspected, and we provide an enumeration method for determining an optimal value of K which minimizes the number of items inspected.

• Journal of the Korean Operations Research and Management Science Society
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• v.35 no.1
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• pp.97-109
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• 2010

In this paper, we study a joint design problem of sampling inspections and service capacities for multi-products. Products are supplied in batches after rectifying inspections, that is, rejected lots are 100% inspected and defective products are reworked to good ones. When supplied, all defective products are uncovered through total inspection and returned to service. By exploiting the first and second order properties of the objective function, we identify the optimal inspection policies and service capacities for individual products, and develop allocation algorithms to obtain an optimal allocation of the limited total service capacity to products with the small number of computations.

• Journal of Applied Reliability
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• v.1 no.1
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• pp.35-46
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• 2001

Replacement policy of a degradation system is investigated by incorporating the loss function. Loss function is defined by the deviation of the value of quality characteristic from its target value, which determines the loss cost. Cost function is comprised of the inspection cost, replacement cost and loss cost. Two cost minimization problems are formulated : 1)determination of an optimal inspection period given the state for the replacement and 2)determination of an optimal state for replacement under fixed inspection period. Simulation analysis is performed to observe the variation of total cost with respect to the variation of the parameters of loss function and inspection cost, respectively As a result, parameters of loss function are seen to be the most sensitive to the total cost. On the contrary, inspection cost is observed to be insensitive. This study can be applied to the replacement policy of a degradation system which has to produce the quality critical product.

• The Korean Nurse
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• v.32 no.5
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• pp.78-92
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• 1994

The purposes of this study were to evaluate the results of the hospital self inspection with the medical insurance and to offer basic materials to the medical insurance inspection and the education of medical insurance. The study was undertaken with 4,730 cases among the total 13,810 medical insurance in patients from Jan. 1990 to Dec. 1990 at one university hospital in Pusan. The major contents of the inspection were the omission of diagnosis and medical fee, curtailment, application mistake, the rates of inclusion, subtraction and total accumulation. The data were collected using patients charts and bills. The results of the paper analysis were as follows. 1. From the pre-discharge hospital self inspection, major omission were treatment and material fee but medication fee were moderately high and high curtailment was operation fee. 2. Decreasing order of operation fee adjustment were digestive(22.4%) muscular(22%) and neuro system operation(21.4%). Majority of the medication fee adjustments were injection form of medication(95.7%). 50% of the treatment fee adjustments were composed of injection fee(27.9%) and dressing or post-operative dressing fee(22.3%). 74.7% of material costs were composed of oxygen(30.6%), blood and the blood composed materials(44.1%). 3. Pre-discharge inspection showed 6% adjustment rate, 4.3% addition and 2.1% curtailment rate. Most of the adjustment were omission(66.1%). 4. Omission were divided by event omission(92.6%)and application mistake(7.4%). The decreasing order of omission fee were operation(21.84%), treatment(18.71 %) diagnosis(18.68%), medication (14.53%) and material costs(10.84%). So operation and treatment part were the major part of the total omission fee(40.55%). 5. The average omission of diagnosis were 1,800 per month.

• Journal of Industrial Technology
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• v.3
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• pp.27-32
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• 1983

This paper develops and provides formulas for calculating the Average Outgoing Quality and the Average Total Inspection for nine different sample/rest-of-lot disposition policies in which rectifying multiple sampling inspection by attribute can be carried out. The formulas are considered for perfect inspection as well as error-prone inspection.