• Title/Summary/Keyword: Sampling inspection

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Improvement of Predictive and Corrective Inspection Methods to Control Nosema bombycis Infection in the Silkworm, Bombyx mori

  • Nguyen, Mau-Tuan;Jon
    • Journal of Sericultural and Entomological Science
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    • v.39 no.2
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    • pp.146-153
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    • 1997
  • The microsporidian infection with Nosema bombycis, reconfirmed its high virulence and transovarial tranmissibility, however, the characteristic symptom of the spots like pepper grains on the diseased larval skin was no more recognized by present varieties of the silkworm. Transovarial transmission rate detected from moth was above 90% in dead eggs or dead larvae in the rearing by mulberry leaves, 80% in the newly hatched larvae starved to death. Transovarially transmitted N. bombycis was easily observed from dead eggs and larvae, and were suggested an individual inspection of a few of dead eggs for detection of the pathogenic spores. The progeny population provided indicative factors on the sampling of predictive and corrective inspection. The higher concentration of N. bombycis spores included in the hindabdormal part of infected moth, applicative on the simple method of indivisual moth inspection. For the predictive inspection of growned 5th-instar larvae, N. bombycis infection was detectable without microscopic observation by the unique symptom of turbid milky-white spots on the silk gland. Inspection of the meconia artificially discharged from silkworm moth, was also succesful of microscopic observation before crossing, without killing or homogenize the moths. The results provided a basis of rational methods for the inspection of N. bombycis infection of the silkworm.

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A Case Study for Estimating the Defect Rate of PLC Using Sampling Inspection and Improving the Cause of Defects (샘플링검사를 이용한 PLC의 불량률 추정 및 불량원인 개선 사례연구)

  • Moon, In-Sun;Lee, Dong-Hyung
    • Journal of Korean Society of Industrial and Systems Engineering
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    • v.44 no.4
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    • pp.128-135
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    • 2021
  • WDM(Wavelength Division Multiplexing) is called a wavelength division multiplexing optical transmission method and is a next-generation optical transmission technology. Case company F has recently developed and sold PLC(Planar Lightwave Circuit), a key element necessary for WDM system production. Although Chinese processing companies are being used as a global outsourcing strategy to increase price competitiveness by lowering manufacturing unit prices, the average defect rate of products manufactured by Chinese processing companies is more than 50%, causing many problems. However, Chinese processing companies are trying to avoid responsibility, saying that the cause of the defect is the defective PLC Wafer provided by Company F. Therefore, in this study, the responsibility of the PLC defect is clearly identified through estimating the defect rate of PLC using the sampling inspection method, and the improvement plan for each cause of the PLC defect for PLC yeild improvement is proposed. The result of this research will greatly contribute to eliminating the controversy over providing the cause of defects between global outsourcing companies and the head office. In addition, it is expected to form a partnership with Company F and a Chinese processing company, which will serve as a cornerstone for successful global outsourcing. In the future, it is necessary to increase the reliability of the PLC yield calculation by extracting more precisely the number of defects.

Development of Automatic Program for Noise Inspection of Auto-transmission (자동변속기(Auto-Transmission)의 이상음 검사자동화 시스템개발)

  • 김재열
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.9 no.6
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    • pp.9-18
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    • 2000
  • This study includes noise automatic inspection system for washing machine auto-transmission one of modern home necessary. We effort to find and certificate sound noise source by sound power and sound intensity, and apply to frequency analysis in vibration related sound noise. still more we have been studying to data acquisition and programming for MS VisualBasic version 5.0. System component is below. 1) Pentium PC or data acquisition. 2) DSO for noise acquisition. 3)S/W for comparison and decision. 4) I/F Board for data communication. Wave form data through the DSO are converting to ASCII code data. The ASCII code through binary converting S/W. Finally we will making noise monitoring system and automatic inspection system.

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An Economic Optimization of the Target Value (경제성을 고려한 공정 목표값 최적화)

  • 윤철환;유정현;윤덕균
    • 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.

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A study on equilibrium of the amount of requisite materials and purchasing materials considering the fraction defective of the lot (로트불량율을 고려한 자재소요량과 자재구입량의 균형화 연구)

  • 이회식
    • Journal of Korean Society of Industrial and Systems Engineering
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    • v.9 no.13
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    • pp.13-16
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    • 1986
  • In this paper we study the decision rule for the amount of purchasing materials according to the fraction defective in the single sampling inspection by attributes based on operating characteristics. In deciding the amount of purchasing materials, it is important that we ought to occupy the practical purchasing amount, considering the fraction defective of the lot in acceptance inspection, because the acceptance probability is variant with the fraction defective of the lot.

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A Study on the Determination of the Economic Sample Size of the Attribute Acceptance Sampling Plans for Destructive Testing (파괴시험 계수형 샘플링검사 경제적 시료 크기 결정에 관한 연구)

  • 김병재
    • Journal of Korean Society of Industrial and Systems Engineering
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    • v.4 no.5
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    • pp.11-14
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    • 1981
  • This study intends to decide the economic sample size based on the cost of sampling Inspection for destructive testing. The marginal percent defective is used as the lot tolerance percent defective (LTPD), and the Newton's iterative method is adopted to calculate the optimum sample size(n), given by the consumer's risk($\beta$ - risk) and the acceptance number(c).

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