• Journal of Korean Society for Quality Management
• /
• v.21 no.1
• /
• pp.65-77
• /
• 1993

Often in a production process, the quality of items is serially dependent. We assume that the quality of items is an attribute which can be classified as good or bad with a Markovian dependence structure. In order to determine sampling inspection plan characteristics such as total inspection cost and average outgoing quality, we design an economic model and illustrate an efficient procedure for design of best inspection plan using graphs based on numerical calculations.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2020.06a
• /
• pp.220-221
• /
• 2020

Strarting with Buyeong Apartment in Dongtan-2 disrict in 2017, collective complaints of residents are frequently occurring due to low quality problem such as improper construction and defects of apartment houses. Because of this, the Ministry of Land and Transport is preparing a comprehensive improvement scheme to improve the quality of Apartment Housing(AH), taking into account the continuing complaints from the residents of AH and the problem raised by the National Assembly. The basic profile of the improvement scheme is induce the tenants and experts to discover and point out defects that are repaired until the date of use inspection or due date. For this purpose, we suggested this defects management system linkaged by the preliminary inspection and quality inspection system for prospective occupants. In this context, this paper aims to suggest an effective likage method between the preliminary inspection of prospective residents and the quality inspection system implemented by local governments as an ordinance.

• Industrial Engineering and Management Systems
• /
• v.16 no.1
• /
• pp.1-21
• /
• 2017

This paper discusses a reverse supply chain (RSC) which consists of the process flows from procurement of used products collected from a market, through remanufacturing products from the used products, to sales of the products in a market. In general, it is conceivable for the RSC to face the uncertainty in quality of used products collected from a market. Inspection is one of efficient methods to deal with the problem regarding quality of used products. However, there is a trade-off between inspection cost and inspection accuracy. This paper focuses on the following five types of inspection: (1) 100% inspection, (2) sampling inspection, (3) sampling inspection with screening of rejected lots, (4) sampling inspection with screening of acceptable lots, and (5) no inspection, and determines the optimal operation consisting of the optimal number of procured used products and the optimal inspection policy. Numerical analysis clarifies not only how changes of conditions of the RSC affect the manufacturer's optimal operation but also features of each inspection type. In addition, from the results of numerical analysis, this paper shows the usability to add the proposed inspection in this paper, the sampling inspection with screening of acceptable lots, to choices of inspection type.

• Journal of Korean Society for Quality Management
• /
• v.11 no.2
• /
• pp.37-41
• /
• 1983

Nine different rectification inspection policies are considered. For each variation, the cost breakeven points between acceptance without inspection, 100% inspection and sampling inspection are evaluated in both cases where process average is constant and varies as a beta distribution.

• Journal of Korean Society for Quality Management
• /
• v.27 no.3
• /
• pp.113-124
• /
• 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 Korean Society for Quality Management
• /
• v.23 no.4
• /
• pp.74-89
• /
• 1995

In recent years, the safety of customers and the demand for rights to be protected from the risk have become stronger than ever day by day, and the function concerning product liability(PL) and quality assurance(QA) has been emphasized. Basically these functions can be obtained by inspection and there is the single rectifying sampling inspection for attribute (KSA-3105) as an existing method. But we can not say this method is good enough because of limitations in the range of applications and the approximate design of inspection methods which can not meet the rapidity and accuracy of quality information transfer according to the maturity of information period. Therefore, in this paper, a new algorithm is developed which can design the accurate inspection method by using the linear cost function that has not been considered in the existing inspection methods. Also in addition to this, a optimal rectifying sampling inspection plan, contributing to minimize the total costs, can be developed by programming the algorithm developed in this study and it can be applied to any field having many processes almost limitlessly.

• Journal of Korean Institute of Industrial Engineers
• /
• v.27 no.3
• /
• pp.297-304
• /
• 2001

Procurement decisions for inspection equipment are often made heavily based on the initial purchase price instead of the effects of inspection cost, equipment calibration and utilization over the lifetime. Cost of ownership(COO) models that take into account all of these cost factors together have been developed focusing on a single quality characteristic. In modern manufacturing environment, inspection equipment often can deal with more than one quality characteristic simultaneously. In this paper, we propose the revised COO model for the economic evaluation of the inspection equipment that can accommodate multiple quality characteristics. We also employ an engineering economy model to compare equipments with different life span. Software is developed for handy comparison of the COO of alternative equipments along with sensitivity analysis far the optimal procurement decision.

• Journal of the Korean Society for Precision Engineering
• /
• v.20 no.9
• /
• pp.92-99
• /
• 2003

Quality inspection of textile products is an important problem for fabric manufacturers. This paper presents an automatic vision-based system for quality control of web textile fabrics. Typical web material is 1-3m wide and is driven with speeds ranging from 20m/min to 200m/min. At the present, the quality assessment procedures are performed manually by expert. But worker can not detect more than 60％ of the present defect and inspect the fabric if moving faster than 30m/min. To increase the overall quality and homogeneity of textile, an automated visual inspection system is needed fur the productivity. However, the existing inspection system are too expensive to purchase for small companies. In this paper, the proposed PC based real-time inspection algorithm gives low cost textile inspection system, high detection rate with good accuracy and low rate of false alarms. The method shows good results in the detection of several types of fabric defects.

• Journal of Korean Institute of Industrial Engineers
• /
• v.22 no.3
• /
• pp.473-483
• /
• 1996

For situations where there are several markets with different price/cost structures, economic complete inspection plans are developed for determining the market to ship the product to. Two complete inspection plans are considered; the plan based on the performance variable of interest, and the plan based on a variable which is correlated with the performance variable. Profit models are constructed which involve selling price, cost incurred by imperfect quality, and quality inspection cost. Methods of finding the optimal complete inspection plans are presented and a numerical example is given.

• Journal of the Korea Safety Management & Science
• /
• v.21 no.4
• /
• pp.67-74
• /
• 2019

Visual inspection is regarded as one of the critical activities for quality control in a manufacturing company. it is thus important to improve the performance of detecting a defective part or product. There are three probable working modes for visual inspection: fully automatic (by automatic machines), fully manual (by human operators), and semi-automatic (by collaboration between human operators and automatic machines). Most of the current studies on visual inspection have been focused on the improvement of automatic detection performance by developing a better automatic machine using computer vision technologies. However, there are still a range of situations where human operators should conduct visual inspection with/without automatic machines. In this situation, human operators'performance of visual inspection is significant to the successful quality control. However, visual inspection of components assembled into a mobile camera module belongs to those situations. This study aims to investigate human performance issues in visual inspection of the components, paying more attention to human errors. For this, Abstraction Hierarchy-based work domain modeling method was applied to examine a range of direct or indirect factors related to human errors and their relationships in the visual inspection of the components. Although this study was conducted in the context of manufacturing mobile camera modules, the proposed method would be easily generalized into other industries.