• Title, Summary, Keyword: Inspection

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A Sampling Inspection Plan with Human Error: Considering the Relationship between Visual Inspection Time and Human Error Rate

  • Lee, Yong-Hwa;Hong, Seung-Kweon
    • Journal of the Ergonomics Society of Korea
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    • v.30 no.5
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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.

Deep Learning Based Real-Time Painting Surface Inspection Algorithm for Autonomous Inspection Drone

  • Chang, Hyung-young;Han, Seung-ryong;Lim, Heon-young
    • Corrosion Science and Technology
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    • v.18 no.6
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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.

Sequential Design of Inspection Times in Optimally Spaced Inspection

  • Park San-Gun;Kim Hyun-Joong;Lim Jong-Gun
    • Communications for Statistical Applications and Methods
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    • v.13 no.1
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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.

A Study on the Safety Inspection of the T-Beam Bridges (철근콘크리트 T형교의 안전진단에 관한 연구)

  • 채원규
    • Journal of the Korean Society of Safety
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    • v.10 no.1
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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.

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Development of Bridge Inspection Reliability and Improvement Strategy (교량 점검신뢰도 분석법 개발과 향상방안)

  • Jeong, Yo-Seok;Kim, Woo-Seok;Lee, Il-Keun;Lee, Jae-Ha
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.20 no.5
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    • pp.50-57
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    • 2016
  • The present study proposed three inspection reliability indices which compared inspection results evaluated at in-depth(routine) inspection and in-depth safety inspection; Nominal inspection reliability index, Real inspection reliability index, and DS nominal inspection reliability index. The methods to improve the inspection reliability were also proposed. Since bridge inspection process is critical to ensuring the safety of bridges and identifying repair and maintenance needs, the quality of the inspection data produced from the inspection process is very important. Consequently, the inspection reliability indices were suggested to evaluate quality of current inspection practices. Specifically, approximately 85% of inspection errors evaluated by the DS nominal inspection reliability index are within 1 rating grade(equal to or less than damage score ${\pm}0.1$). In order to improve the inspection reliability, transportation agency should implement QC(Quality Control) practices and develop professional expertises of inspectors by higher requirements for inspectors, on-off line inspection training and etc.

Application of Generic Algorithm to Inspection Planning of Fatigue Deteriorating Structure

  • Kim, Sung-chan;Fujimoto, Yukio;Hamada, Kunihiro
    • Journal of Ship and Ocean Technology
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    • v.2 no.1
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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.

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Optimal Operation for Reverse Supply Chain Incorporating Inspection Policy into Remanufacturing of Used Products

  • Yamaguchi, Shin;Kusukawa, Etsuko
    • Industrial Engineering and Management Systems
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    • v.16 no.1
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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.

Histogram Specification Method Development for Accurate Visual Inspection (정확한 비전 검사를 위한 히스토그램 지정 기법 개발)

  • Park, Se-Hyuk;Kang, Su-Min;Han, Kwang-Hee;Huh, Kyung-Moo
    • Proceedings of the KIEE Conference
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    • pp.145-146
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    • 2008
  • The appearance inspection of various electronic products and parts has been executed by the eyesight of human. But inspection by eyesight cannot bring about uniform inspection result. Because the appearance inspection result by eyesight of human is changed by condition of physical and spirit of the checker. So machine vision inspection system is currently used to many appearance inspection fields instead of the checker. However the inspection result of machine vision is changed by the illumination of workplace. Therefore we proposed histogram specification in this paper for machine vision inspection accuracy. As a result of histogram specification algorithm, we could increase the exactness of visual inspection and prevent system error from physical and spirit condition of human. More specifically, average inspection error rate was 7.5[%] in existing inspection method but we could see 0.6[%] error rate after applying the algorithm which is presented in this paper.

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The Importance of Self-Inspection in Accident Prevention (자체검사제도가 갖는 재해예방 효과)

  • 백종배
    • Journal of the Korean Society of Safety
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    • v.16 no.4
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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.

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