• Journal of Korean Society for Quality Management
• /
• v.24 no.4
• /
• pp.207-223
• /
• 1996

These days, customers have attached great importance to the function of product liability and quality assurance. In Korea, the single rectifying sampling inspection for attribute (KS A 3105) has been used. But this inspection plan given by tables (KS A 3105) has some defects. There are limitations in the range of applications and irrationality of approximate probability and the double rectifying sampling inspection is not mentioned. Moreover, ATI (average total inspection) does not reflect sampling costs and the loss of nonconforming item. Therefore, the objectives of this study is to develope new algorithms and computer program that provide the optimal sampling inspection plan based on minimum linear costs (single & double inspection plan). The result of this study revealed that the new algorithm is less than KS A 3105 in ATI and basically, double inspection plan is more economical. Also it comes over restrictions in KS A 3105. So, it is definite that the optimal solution can be obtained considering cost factors in manufacturing and sampling process, and costs can be saved in the long term.

• Industrial Engineering and Management Systems
• /
• v.8 no.3
• /
• pp.131-138
• /
• 2009

The variable sampling inspection scheme with screening for the purpose of assuring the upper limit of maximum expected surplus loss after inspection has been proposed. In this inspection scheme, it has been assumed that a product lot consists of products manufactured through a single production line and lot quality characteristics follow a normal distribution. In the previous literature with respect to inspection schemes, it has been commonly assumed that lot quality characteristics obey a single normal distribution under the condition that all products are manufactured in the same condition. On the other hand, the production line is designed in order that the workload of respective processes becomes uniform from the viewpoint of line balancing. One of the solutions for the bottleneck process is to arrange the workshops in parallel. The lot quality characteristics from such a production line with the process consisting of some parallel workshops might not follow strictly the single normal distribution. Therefore, we expand an applicable scope of the above mentioned variable sampling inspection scheme with screening in this article. Concretely, we consider the variable sampling inspection with screening for the purpose of assuring the upper limit of average outgoing surplus quality loss in the production lots when the lot quality follows the mixed normal distribution.

• Journal of the Korean Society of Safety
• /
• v.32 no.1
• /
• pp.53-59
• /
• 2017

Safety inspection activities of the facilities including the electricity, gas, building, and firefighting, etc. are individual checks by the separate law of each government department, comprehensive inspections for the specific managed facilities or during a weak season, and national safety overall diagnostics for the disaster prevention. Thus, types of the inspections are various and they have been carried out repeatedly as well as duplicately. That can make the people or institutes to take such inspections feel great burdens. Therefore, the investigation on the current situation of the individual inspection by the separate law for the electricity, gas, building, and firefighting, etc. as well as of various others by the government needs to be carried out and according to the results the repetitive and duplicated inspections should be reduced and converged to one comprehensive one. In this regard, we proposed solutions to improve the government safety inspection system, function, and role.

• Journal of Korean Society for Quality Management
• /
• v.33 no.4
• /
• pp.88-95
• /
• 2005

Multistage screening is a common practice when a component has a critical effect on the function of the assembly. A defect in a component might incur malfunction of an electronic device, resulting in a great amount of loss. Multistage screening, including duplicated screening inspections, may provide a good solution for this problem when inspection errors are present. In the company studied here, the manufacturing process of the multiple layer chip capacitor includes two-stage screening. In the first stage, screening inspection is performed repeatedly until no defects are found in the lot. In the second stage, sampling inspection is performed by a group of experts prior to shipment. In this article, we review the procedure used in the field and suggest a revised model of the multiple screening procedure and solution method for this situation. The usefulness of the proposed model is discussed through a practical example.

• Journal of Korean Society for Quality Management
• /
• v.32 no.4
• /
• pp.208-219
• /
• 2004

This paper considers a nonparametric estimation of lifetime distribution for ramp stress tests with stress bound under intermittent inspection. The test items are inspected only at specified time points an⊂1 so the collected observations are grouped data. Under the cumulative exposure model, two nonparametric estimation methods of estimating the lifetime distribution at use condition stress are proposed for the situation which the time transformation function relating stress to lifetime is a type of the inverse power law. Each of items is initially put on test under ramp stress and then survivors are put on test under constant stress, where all failures in the Inspection interval are assumed to occur at the midi)oint or the endpoint of that interval. Two proposed estimators of quantile from grouped data consisting of the number of items failed in each inspection interval are numerically compared with the maximum likelihood estimator(MLE) based on Weibull distribution.

• Journal of the Korean Operations Research and Management Science Society
• /
• v.35 no.1
• /
• pp.97-109
• /
• 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 Korea Multimedia Society
• /
• v.25 no.6
• /
• pp.833-843
• /
• 2022

Based on the problems of untimely Expressway fire rescue and backward traditional fire rescue methods, an emergency fire fighting and inspection robot riding on expressway guardrail is designed. The overall mechanical structure design of emergency fire fighting and inspection robot riding on expressway guardrail is completed by using three-dimensional design software. The target fire detection is realized by using the target detection algorithm of Yolov5; By selecting a variety of sensors and using the control method of multi algorithm fusion, the basic function of robot on duty early warning is realized, and it has the ability of intelligent fire extinguishing. The BMS battery charging and discharging system is used to detect the real-time power of the robot. The design of the expressway emergency fire fighting and inspection robot provides a new technical means for the development of emergency fire fighting equipment, and improves the reliability and efficiency of expressway emergency fire fighting.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.22 no.10
• /
• pp.34-40
• /
• 2008

In this paper, a device for safety inspection of a guard lamp with an automatic switch which has been recently employed in some local autonomous entities was developed. It is technically enhanced by installing a separate inspection box down below, which allows the inspectors can measure the leakage current, the sound function of the electric leakage breaker(ELB), the insulation resistance and the grounding resistance, on the ground. This inspection box makes the inspectors free from the electric shock by being designed to minimize the potential direct contact with the energized terminals. The deliverables of this paper are expected to contribute to carry out the inspection for the guard lamps safely and effectively.

• Proceedings of the Korean Operations and Management Science Society Conference
• /
• 2000.04a
• /
• pp.469-472
• /
• 2000

Replacement policy of a degradation of system is investigated by incorporating the loss function defined by the deviation of the value of quality characteristic from its target value, which determines the 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 inspect ion period. Simulation analysis is performed to observe the variation of total cost with respect to the variation of the parameters of loss function, inspection cost, respectively. As a result, parameters of loss function are seen to be the most sensitive to the total cost. On the contrary, inspect ion cost is observed to be insensitive.

• The Korean Journal of Applied Statistics
• /
• v.10 no.2
• /
• pp.375-384
• /
• 1997

In this paper, chain-shaped multi-level skip-lot sampling plan is designed, which is a normal inspection plan between Choi(1993)'s tightened inspection plan and Choi(1995)'s reduced inspection plan. In every skipping inspection of the proposed plan, when designed numbers of consecutively inspected lots are accepted, switch to the next skipping inspection, and when a lot is rejected, switch to the skipping inspection of two-level lower. Also, the formulae of the operating chareacteristic function, average sampling number and average outgoing quality for the proposed skip-lot sampling plan are derived using the morkov chain approach and their properties are studied and graphically compared with those of the other multi-level skip-lot sampling plans.