• Journal of Korea Society of Industrial Information Systems
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• v.27 no.2
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• pp.71-82
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• 2022

In order to replace the sampling tensile test of products produced in the tab welding process, which is one of the automotive battery manufacturing processes, vision inspectors are currently being developed and used. However, the vision inspection has the problem of inspection position error and the cost of improving it. In order to solve these problems, there are recent cases of applying deep learning technology. As one such case, this paper tries to examine the usefulness of applying Faster R-CNN, one of the deep learning technologies, to existing product inspection. The images acquired through the existing vision inspection machine are used as training data and trained using the Faster R-CNN ResNet101 V1 1024x1024 model. The results of the conventional vision test and Faster R-CNN test are compared and analyzed based on the test standards of 0% non-detection and 10% over-detection. The non-detection rate is 34.5% in the conventional vision test and 0% in the Faster R-CNN test. The over-detection rate is 100% in the conventional vision test and 6.9% in Faster R-CNN. From these results, it is confirmed that deep learning technology is very useful for detecting welding error of lead tabs in automobile batteries.

• Journal of the Korean Institute of Gas
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• v.7 no.1 s.18
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• pp.33-40
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• 2003

In this work, a novel approach was introduced to assess cost of loss resulting from risk as well as to help deciding inspection period through quantifying risk. In order to quantifying risk of city gas pipeline, frequency and consequence analysis were required. The main causes of city gas accident were analyzed to be digging, external corrosion, ground movement, and equipment failure. Tools to evaluate frequency of each cause was also suggested. Among city gas accidents, fire damage is the dominant one and mainly discussed; fatality, burning injury, and damage to building were estimated using the consequence model suggested. By combining frequency and consequence analysis, evaluating cost of risk management together with calculating example. This work could be applicable for city gas companies to plan how to manage risk most effectively.

• Proceedings of the National Institute of Ecology of the Republic of Korea
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• v.2 no.1
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• pp.26-31
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• 2021

Reproduction and molt are costly processes in avian life histories. These two fitness-related traits are expected to be under one of physiological trade-offs. Age-related molt is known to be higher in young birds than that in adults presumably due to the cost of reproduction in adults. The present study partially replicated a previous study using a non-invasive method of seasonal wing feather loss instead of capture-inspection for molting progress in oriental storks (Ciconia boyciana). We first examined characteristics of the known six wing feather types (i.e., primaries [P], primary coverts [PC], secondaries [S], secondary coverts [SC], and tertials [T]) from two specimens with four wings. Results were utilized as references for further investigation. We then collected a total of 3,807 wing feathers shedded by 61 captive storks for one year and classified them into six wing feather types based on the reference with structures of vane (i.e., how asymmetrical) and calamus (i.e., how rigidly attached to skin) of wing feathers. Our results indicated that annual losses of all six-type wing feathers decreased with increasing ages, ranging from 29% to 58% for PC, alula, SC, P, S, and T in order. Our results were also comparable to those of a former study, suggesting that the pattern of age-specific molt might be associated with the cost of reproduction in adults. However, juveniles might shed more wing feathers with low quality formed during the previous development stage than older birds.

• Journal of the military operations research society of Korea
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• v.11 no.2
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• pp.64-68
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• 1985

This paper considers the following case: (1) the product is paid by the right price for a lot accepted by a given consumer's acceptance sampling plan, and (2) the product is paid by the discounted price for a lot rejected by this plan. In such a case, the producer's sampling plan need not be the same as that of the consumer's. From the producer's view point, the producer need to determine the preliminary sample size which maximizes his revenue. This paper, therefore, determines an optimal preliminary sample size from the producer's view point. This preliminary sample size is affected by the consumer's acceptance sampling plan, percent defective, preliminary inspection cost and the discount rate of the price.

• Proceedings of the KSR Conference
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• 2011.05a
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• pp.1174-1181
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• 2011

This paper investigates the current established preventive maintenance and its corresponding data on a point machine among railway signalling facilities and suggests a part of considerable plans when the policy of the preventive maintenance is modified. It is not appropriated to apply the optimized preventive replacement period considered with the cost simply. In that case, it is suggested that the reliability should be analyzed failure mode and effects through collecting the on-site failure data sufficiently. Then, that result can be proposed to adjust the proper criteria into the rational way by comparing the initial maintenance criteria. In this paper, the alternative way to determine the feasibility of the inspection period using failure probability is introduced.

• Journal of Korean Institute of Industrial Engineers
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• v.32 no.1
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• pp.51-60
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• 2006

When the nature of measuring a performance variable is destructive or very expensive, it is attractive to use a surrogate variable which is highly correlated with the performance variable and less expensive to measure. In this paper, we propose rectifying screening procedures using the performance and surrogate variables. Two screening procedures are considered; a statistically-based screening procedure to reduce the current proportion of nonconforming items to a specified lower value after screening, and an economically-based screening procedure where the screening limit is determined so that the expected cost is minimized. It is assumed that the surrogate variable given the performance variable is normally distributed with known mean and standard deviation. For two screening procedures, methods of finding the optimal solutions are presented and numerical examples are also given.

• Agribusiness and Information Management
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• v.9 no.1
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• pp.1-6
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• 2017

Recent scandals of milk additives in several developing countries provoked controversy about quality issue of dairy products, grapping academic attention to the dairy supply chain. In this paper, we first focus on moral hazard problem of self-interested entities about the quality across the dairy supply chain, due to unobservable and unverifiable quality management efforts of all entities - including dairy producers, stations, and a final producer - and high inspection cost for the quality. Based on the identified moral hazard problem, we understand why the adoption of IoT-based tracking systems about quality produced from each entity is a must, different from RFID-based tracking systems.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.28 no.6
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• pp.867-875
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• 2004

In order to inspect burr geometry and hole quality in micro-drilling processes, a cost-effective method using an image processing and shape from focus (SFF) methods on the machine tool is proposed. A CCD camera with a zoom lens and a novel illumination unit is used in this paper. Since the on-machine vision unit is incorporated with the CNC function of the machine tool, direct measurement and condition monitoring of micro-drilling processes are conducted between drilling processes on the machine tool. Stainless steel and hardened tool steel are used as specimens, as well as twist drills made of carbide are used in experiments. Validity of the developed system is confirmed through experiments.

• Journal of Korean Institute of Industrial Engineers
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• v.14 no.1
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• pp.83-89
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• 1988

Optimal screening procedures with dichotomous performance variable T and continuous screening variable X are presented for assuring with a specified degree of confidence that at least ${\ell}$ out of m items found acceptable in screening inspection are conforming. It is assumed that T is a Bernoulli random variable and that the conditional distribution of X given T=t is normal. When m is also to be determined, optimal m and cut-off value of X minimizing the total expected cost are obtained. Cases of known and unknown parameters are considered and for unknown parameter cases, Bayesian approaches are used to find the optimal screening procedures.

• 한국생물공학회:학술대회논문집
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• 2003.10a
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• pp.259-262
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• 2003

In this study, batch production of lactic acid from cheap law material such as barley, wheat, and corn, was tried to lower the total production cost of lactic acid. Although no nutrients were supplemented, lactic acid productivities were achieved up to 0.88 $g/(L{\cdot}hr)$ from barley, wheat and com enzymatic hydrolysate. By adding corn steep liquor to com and wheat hydrolysate media, realtively high lactic acid $productivities(4.14\;g/(L{\cdot}hr))$ were obtained.