• 산업경영시스템학회지
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• 제40권4호
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• pp.96-104
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• 2017

A one-shot system (device) refers to a system that is stored for a long period of time and is then disposed of after a single mission because it is accompanied by a chemical reaction or physical destruction when it operates, such as shells, munitions in a defense weapon system and automobile airbags. Because these systems are primarily related with safety and life, it is required to maintain a high level of storage reliability. Storage reliability is the probability that the system will operate at a particular point in time after storage. Since the stored one-shot system can be confirmed only through inspection, periodic inspection and maintenance should be performed to maintain a high level of storage reliability. Since the one-shot system is characterized by a large loss in the event of a failure, it is necessary to determine an appropriate inspection period to maintain the storage reliability above the reliability goal. In this study, we propose an optimal inspection policy that minimizes the total cost while exceeding the reliability goal that the storage reliability is set in advance for the one-shot system in which periodic inspections are performed. We assume that the failure time is the Weibull distribution. And the cost model is presented considering the existing storage reliability model by Martinez and Kim et al. The cost components to be included in the cost model are the cost of inspection $c_1$, the cost of loss per unit time between failure and detection $c_2$, the cost of minimum repair of the detected breakdown of units $c_3$, and the overhaul cost $c_4$ of $R_s{\leq}R_g$. And in this paper, we will determine the optimal inspection policy to find the inspection period and number of tests that minimize the expected cost per unit time from the finite lifetime to the overhaul. Compare them through numerical examples.

• 한국산학기술학회논문지
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• 제12권4호
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• pp.1559-1564
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• 2011

본 논문에서는 생산 현장에서 작업자가 육안으로 하고 있는 자동차 부품 카시트 프레임의 전수(全數) 검사를 위한 머신 비전 시스템의 개발에 관한 연구를 다룬다. 이러한 제안된 머신비전 검사시스템은 생산 현장에서 날로 증가하는 품질 향상에 대한 요구와 수요를 충족시키기 위해 설계되었다. 이 컴퓨터 기반의 검사시스템은 실시간으로 제품의 다양한 결함들에 대한 품질 검사를 할 수 있도록 설계되었다. 본 연구의 검사방법에 사용된 소프트웨어는 NI-LabVIEW가 사용하였으며, LabVIEW Vision 이미지 함수를 사용하여 검사 프로그램을 개발하였다. 개발된 검사 알고리즘은 생산 부품의 실시간 검사에 적용 될 수 있으며, 검사 영역과 설정 값을 비전 시스템 운용자가 설정할 수있도록 프로그램이 만들어져 검증되었다. 제안된 검사시스템은 카시트 프레임 검사를 성공적으로 수행하였다.

• 한국안전학회지
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• 제38권4호
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• pp.47-53
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• 2023

In the inspection of workplace hazards/risk factors by specialized institutions dedicated to safety management, inspection reports vary based on the inspectors, who lack the authority to enforce improvement of workplace hazards/risk factors. Thus, improvement and accident rates remain steady without decreasing. This study performed a regression analysis on the relationship between improvement and accident rates of categorized inspection items by classifying hazards/risk factors from inspection reports submitted by a specialized safety management institution in Chungbuk after inspecting 10 food and beverage manufacturers over the past three years. The hazards/risk factors were classified into five categories: mechanical, electrical, chemical, human, and environmental. The regression analysis revealed that the improvement rate of hazards/risk factors inspected by the specialized safety management institution influenced accident rates. To enhance improvement rates based on these findings, this study prioritized the correction of the five most frequently cited inspection items with the lowest improvement rates in each area. Based on these inspection items, this study suggested a checklist for use in workplace safety inspections of food manufacturers. This proposed checklist is expected to reduce accident rates in food manufacturing facilities. Currently, guidance and inspection of workplaces are mainly focused on accident rates rather than correcting hazards/risks. Thus, accident rates remain unchanged as workplace risks are inadequately improved according to the unique characteristics of each workplace. When conducting workplace guidance and inspection, policy measures and inspection methods are warranted to increase the improvement rate of hazards/risks.

• 전기전자학회논문지
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• 제28권3호
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• pp.474-478
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• 2024

본 논문에서는 의약 용기의 다중카메라 인라인 검사 시스템에서의 품질 검사를 위한 딥러닝 네트워크를 제안한다. 제안하는 딥러닝 네트워크는 현장에서 생산되는 의약 용기의 데이터를 사용하여 의약 용기에 특화된 딥러닝 네트워크로 더욱 정확하게 품질을 검사한다. 또한, 인라인 검사가 가능한 딥러닝 네트워크를 사용하여 품질 검사의 속도를 증대시킬 수 있다. 다중카메라 인라인 검사 시스템에서의 품질 검사를 위한 딥러닝 네트워크의 개발은 3단계로 나뉜다. 첫 번째로 실제 의약 용기 생산 현장에서 1개의 이물검사용 line 카메라, 3개의 치수검사용 area 카메라를 통해 얻은 약 10,000장의 이미지로 데이터셋을 구축한다. 두 번째로 의약 용기 데이터 전처리에서는 이물 검사, 치수검사의 용도에 맞게 불량이 일어날 수 있는 곳에 ROI를 지정하여 데이터를 전처리한다. 세 번째로 전처리된 데이터를 이용하여 딥러닝 네트워크를 학습한다. 딥러닝 네트워크는 적은 채널 수를 적용하여 linear layer를 사용하지 않아 판정 속도를 향상하고, PReLU와 residual learning를 적용하여 정확도를 향상한다. 이를 통해 4개의 카메라에서 구축한 데이터셋에 맞는 4개의 딥러닝 모듈을 제작한다. 제안된 의약 용기의 다중카메라 인라인 검사 시스템에서의 품질 검사를 위한 딥러닝 네트워크의 성능을 평가하기 위하여 공인시험기관에서 실험한 결과는, 딥러닝 모듈의 판별 정확도가 99.4%로 세계 최고 수준인 95% 보다 우수한 성적을 달성하였고, 평균 판별 속도가 0.947초로 측정되어 세계 최고 수준인 1초보다 우수한 성적을 달성하였다. 따라서, 본 논문에서 제안한 의약 용기의 다중카메라 인라인 검사 시스템에서의 품질 검사를 위한 딥러닝 네트워크의 효용성이 입증되었다.

• 대한안전경영과학회지
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• 제21권4호
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• pp.67-74
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• 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.

• 한국산학기술학회:학술대회논문집
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• 한국산학기술학회 2007년도 춘계학술발표논문집
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• pp.253-255
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• 2007

The increasing requirement for consistency and quality in the automotive industry started the development of a Machine Vision Inspection System (MVIS) for a car seat bottom cushion frame with the goal of providing a higher precision Inspection System with minimal components and less human intervention. The modifications made to an existing PC-based MVIS were shown to improve the accuracy and precision of the system. By using four monochrome cameras, the working distance was lowered and the image distortions were lessened without resorting to extensive image processing. The inspection scripts were evaluated if it could recognize good and bad products and were shown to be robust and able to reach an acceptable level of precision. It was also shown that the amount of human interaction was lessened.

• Current Optics and Photonics
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• 제1권1호
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• pp.45-50
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• 2017

Optical instruments based on polymer-dispersed liquid crystal (PDLC) have been used to inspect transparent electrodes. Generally the operating voltage of an inspection instrument using PDLC is very high, over 300 V, reducing its lifetime and reliability. The operating-voltage issue becomes more serious in the inspection of touch-screen panel (TSP) electrodes, due to the bezel structure protruding over the electrodes. We have theoretically calculated the parameters affecting the operating voltage as a function of the distance between the TSP and the PDLC, the thickness, and the dielectric constant of the sublayers when the inspection module was away from the TSP electrodes. We have experimentally verified the results, and have proposed a way to reduce the operating voltage by substituting a plastic substrate film with a hard coating layer of smaller thickness and higher dielectric constant.

• Corrosion Science and Technology
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• 제7권4호
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• pp.208-211
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• 2008

Safety operation of main pipelines is primarily provided by anticorrosive monitoring. Anticorrosive monitoring of oil pipeline transportation objects is based on results of complex corrosion inspections, analysis of basic data including design data, definition of a corrosion residual rate and diagnostic of general equipment's technical condition. All the abovementioned arrangements are regulated by normative documents. For diagnostics of corrosion-technical condition of oil pipeline transportation objects one presently uses different methods such as in-line inspection using devices with ultrasonic, magnetic or another detector, acoustic-emission diagnostics, electrometric survey, general external corrosion diagnostics and cameral processing of obtained data. Results of a complex of diagnostics give a possibility: $\cdot$ to arrange a pipeline's sectors according to a degree of corrosion danger; $\cdot$ to check up true condition of pipeline's metal; $\cdot$ to estimate technical condition and working ability of a system of anticorrosive protection. However such a control of corrosion technical condition of a main pipeline creates the appearance of estimation of a true degree of protection of an object if values of protective potential with resistive component are taken into consideration only. So in addition to corrosive technical diagnostics one must define a true residual corrosion rate taking into account protective action of electrochemical protection and true protection of a pipeline one must at times. Realized anticorrosive monitoring enables to take a reasonable decision about further operation of objects according to objects' residual life, variation of operation parameters, repair and dismantlement of objects.

• Journal of the Korean Data and Information Science Society
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• 제15권4호
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• pp.793-801
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• 2004

In this paper, we propose control charts for failure rate using the number of failures based on the fixed interval inspection with replacement. And we investigate the power of detection of the proposed control charts by the ARL.

• 한국산학기술학회논문지
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• 제15권6호
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• pp.3416-3422
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• 2014

쇼크 업쇼바의 로드는 피스톤부 중심에 위치하여 왕복운동을 담당하는 부분으로 표면의 불량(찍힘)이 있을 경우 감쇠력에 대한 차이로 제품 성능을 제대로 발휘하는데 문제 발생의 요인이 되고 있다. 로드표면은 열처리 상태로 표면 광택으로 인하여 쉽게 불량이 표시되지 않으며, 작업자가 육안으로 로드의 이물질 및 찍힘, 기포 검사를 진행함으로써 눈의 피로도가 높아지고, 작업자 육안에 의존하기 때문에 제품의 검사 품질이 일정하지 않다. 본 연구에서는 제품의 원통 형상을 고려하여 라인스캔카메라를 이용한 머신비전 영상처리 기법으로 0.3mm이상의 표면의 불량을 검출하고, 검사단계에서 발생할 수 있는 표면 불량을 최소화하기 위한 전 공정 자동이송 및 양불 제품의 혼입을 방지하는 자동검사 시스템 개발에 대한 연구를 수행하였다. 표면검사 시스템 개발로 작업자의 육안 검사에 의존하고 있던 쇼크업쇼버 로드의 표면에 대한 정밀 검사시스템 구축으로 품질검사 기준을 확보하고 표준화된 검사로 신뢰도가 향상되었다.