• 대한인간공학회지
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• 제30권5호
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• pp.645-650
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• 2011

Objective: The aim of this study is to design a sampling inspection plan with human error which is changing according to inspection time. Background: Typical sampling inspection plans have been established typically based on an assumption of the perfect inspection without human error. However, most of all inspection tasks include human errors in the process of inspection. Therefore, a sampling inspection plan should be designed with consideration of imperfect inspection. Method: A model for single sampling inspection plans were proposed for the cases that visual inspection error rate is changing according to inspection time. Additionally, a sampling inspection plan for an optimal inspection time was proposed. In order to show an applied example of the proposed model, an experiment for visual inspection task was performed and the inspection error rates were measured according to the inspection time. Results: Inspection error rates changed according to inspection time. The inspection error rate could be reflected on the single sampling inspection plans for attribute. In particular, inspection error rate in an optimal inspection time may be used for a reasonable single sampling plan in a practical view. Conclusion: Human error rate in inspection tasks should be reflected on typical single sampling inspection plans. A sampling inspection plan with consideration of human error requires more sampling number than a typical sampling plan with perfect inspection. Application: The result of this research may help to determine more practical sampling inspection plan rather than typical one.

• Communications for Statistical Applications and Methods
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• 제13권1호
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• pp.11-17
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• 2006

The spacing of inspection times in intermittent inspection is of great interest, and several ways for the determination of inspection times have been proposed. In most inspection schemes including equally spaced inspection and optimally spaced inspection, the best inspection times in each inspection scheme depend on the unknown parameter, and we need an initial guess of the unknown parameter for practical use. Thus it is evident that the efficiency of the resulting inspection scheme highly depends on the choice of the initial value. However, since we can obtain some information about the unknown parameter at each inspection, we may use the accumulated information and adjust the next inspection time. In this paper, we study this sequential determination of the inspection times in optimally spaced inspection.

• 한국안전학회지
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• 제10권1호
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• pp.50-55
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• 1995

In this thesis, the safety inspection of the T-beam bridges were studied. The stage of the safety inspection were classified according to the importance of the inspection contents the preliminary inspection, the resume inspection, the detail inspection, and the close inspection. By stages, the Inspection contents, the inspection items, and the inspection methods were systematized. And the method of the repair or the reinforcement for the demaged bridges were also suggested.

• 한국구조물진단유지관리공학회 논문집
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• 제20권5호
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• pp.50-57
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• 2016

교량의 안전은 점검에 의해 보장된다. 그리고 교량의 유지관리는 점검결과를 토대로 시작된다. 따라서 점검결과는 '교량의 안전'과 '효율적인 유지관리'를 위한 가장 중요한 정보이다. 따라서 본 논문에서는 교량의 점검신뢰도를 평가하고 이를 제고 할 수 있는 방안을 제시하고자 한다. 이를 위해 본 논문에서는 교량의 점검신뢰도를 평가 할 수 있는 세 가지 점검신뢰도를 제시하였다: 명목점검신뢰도, 실질점검신뢰도, DS명목점검신뢰도. 교량의 점검신뢰도 분석 방법은 정밀안전진단결과를 참값으로 간주하고 당해년도 정밀(정기)점검과 차년도 정밀안전 진단결과를 비교하였다. 인적오류를 고려한 DS명목신뢰도를 기준으로 현재 고속도로교량의 점검신뢰도 85%로 양호한 편으로 평가 된다. 이는 현재 고속도로 교량의 평균공용연수가 13년으로 대부분의 교량이 'A'와 'B'등급에 집중적으로 분포되어 상태변화가 크지 않기 때문인 것으로 판단된다. 점검신뢰도를 제고하기 위해서는 점검자의 역량을 강화하고 전문점검인력 육성이 필요하며 점검결과에 대해 QC(Quality Control, 품질관리)를 실시하여 점검결과의 신뢰도 향상이 필요하다.

• Journal of Ship and Ocean Technology
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• 제2권1호
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• pp.42-57
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• 1998

Genetic Algorithm (GA) is applied to obtain optimal Inspection plan for fatigue deteriorating structures. The optimization problem is defined so as to minimize inspection cost in the 1ifs-time of the structure under the constraint that the increment of failure probability in each inspection interval is maintained below a target value. Optimization parameters are the inspection timing and the inspection quality. The inspection timing is selected from the discrete intervals such as one year, two years, three years, etc. The inspection quality is selected from the followings; no inspection, normal inspection, sampling inspection or precise inspection. The applicability of the proposed GA approach is demonstrated through the numerical calculations assuming a structure consisting of four member sets. Influences of the level of target failure probability, initial defect condition and stress increase due to plate thickness reduction caused by corrosion on inspection planning are discussed.

• Corrosion Science and Technology
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• 제18권6호
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• pp.253-257
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• 2019

A deep learning based real-time painting surface inspection algorithm is proposed herein, designed for developing an autonomous inspection drone. The painting surface inspection is usually conducted manually. However, the manual inspection has a limitation in obtaining accurate data for correct judgement on the surface because of human error and deviation of individual inspection experiences. The best method to replace manual surface inspection is the vision-based inspection method with a camera, using various image processing algorithms. Nevertheless, the visual inspection is difficult to apply to surface inspection due to diverse appearances of material, hue, and lightning effects. To overcome technical limitations, a deep learning-based pattern recognition algorithm is proposed, which is specialized for painting surface inspections. The proposed algorithm functions in real time on the embedded board mounted on an autonomous inspection drone. The inspection results data are stored in the database and used for training the deep learning algorithm to improve performance. The various experiments for pre-inspection of painting processes are performed to verify real-time performance of the proposed deep learning algorithm.

• Industrial Engineering and Management Systems
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• 제16권1호
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• pp.1-21
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• 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.

• 대한산업공학회지
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• 제35권3호
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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.

• 자동차안전학회지
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• 제4권2호
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• pp.17-21
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• 2012

The periodic technical vehicle inspection is to prevent the accident through the finding and fixing the defects of the vehicle. The periodic technical vehicle inspection in Korea was studied for assessing the adequacy of the inspection frequency. The inspection frequencies of many countries including EU, USA and Japan were compared. The average mileages by the vehicle usage and type were represented. The warranty period and recommended replacement period of parts of the domestic auto makers was studied. Currently, the inspection frequency for the periodic technical vehicle inspection in Korea is appropriate. The pass-fail rate and the cost-benefit analysis for the periodic technical inspection in Korea will be needed in the decision making process for the inspection frequency.

• 한국안전학회지
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• 제16권4호
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• pp.175-181
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• 2001

In compliance with the Industrial Safely and Health Acts, the owners/users have performed self-inspection at regular intervals to secure safety in the use of hazardous machinery, equipment and facilities However, securing safety, which is the goal of self-inspection, has not been thoroughly understood in most small businesses and factories. The objective of this research is to analyze the importance and effects of self-inspection in preventing accidents in businesses and factories that use hazardous machinery and facilities. The result shows that self-inspection has made a good contribution to the prevention of accidents. Most businesses and factories that responded the survey answered they have improved safety in the use of machinery and facilities through self-inspection, though the ways of self-inspection were not all the same. However, the result also reveals that there are rooms for further improvement in the areas of self-inspection intervals, self-inspection methods and the selection of self-inspection objects. This improvement is necessary to improve the effect of self-inspection and to minimize regulations of the government on business activities.