• Proceedings of the KAIS Fall Conference
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• 2003.06a
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• pp.325-327
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• 2003

원자력 발전소 2차계통수에는 pH를 조절하여 부식을 억제하기 위해 pH제어제로 암모니아를 사용하였으나 상변화 지역에서 액상의 pH가 낮아 부식생성물이 생성, 증기발생기로 유입되어 진열관의 부식을 촉진 시킨다. pH 제어제로 암모니아 대신 ETA를 도입하여 pH를 증가시키고 증기발생기로 유입되는 부식생성물의 양을 감소하여 진열관의 부식을 억제시키고 있다. 그러나 암모니아에서 ETA로 변경함에 따라 증기 발생기취출수계통의 탈염의 운진기간이 단축되었다. 따라서 본 연구의 목적은 탈염기의 수지 교체주기도 연장시키고 안전성도 확보할 수 있는 탈염기내 양ㆍ음이온 이온교환수지 조성 비율을 최적화하는데 있다. 연속화학평형모델을 이용한 결과 양ㆍ음이온 이온교환수지 비율이 10:1일 경우 최적인 것으로 조사되었다.

• Proceedings of the Korea Information Processing Society Conference
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• 2012.11a
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• pp.60-63
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• 2012

최근 스마트폰 시장에서 제품 수명주기가 계속 짧아지고 있다. 소비자는 항상 최신의 스마트폰을 원하고 있고, 그로 인해 스마트폰 교체시기가 점점 짧아지는 추세이다. 그러나 스마트폰의 교체시 저장되어 있는 개인적인 자료의 백업 및 복원은 필수적이다. 본 논문에서는 소프트웨어적 지식이 없는 소비자들이 안드로이드 시스템에서 터치 몇 번으로 쉽고 간편하게 주소록이나 SMS 메시지 등의 자료를 저장하고 백업할 수 있는 시스템의 개발에 대해서 설명한다. 본 시스템을 이용하면 일반 소비자들이 필요한 자료를 저장하고 백업을 할 수 있어 시간을 절약하고 불필요한 노력을 줄일 수 있을 것으로 기대한다.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.4
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• pp.52-58
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• 2013

Replacement policy is one of the key factors determining the effectiveness of a cache. The LRU replacement policy has remained the standard for caches for many years. However, the traditional LRU has ineffective performance in zero-reuse line intensive workloads, although it performs well in high temporal locality workloads. To address this problem, We propose a new replacement policy; DCR(Dynamic Counter based Replacement) policy. A temporal locality of workload dynamically changes across time and DCR policy is based on the detection of these changing. DCR policy improves cache miss rate over a traditional LRU policy, by as much as 2.7% at maximum and 0.47% at average.

• Journal of the Korean Society for Railway
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• v.11 no.3
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• pp.317-325
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• 2008

As a result of recent research, it is reported that the periodic replacements criterion of rails is able to extend as grinding rail surface and using the continuous welded rail (CWR). This study evaluated correlation between conditions of track and load capacity of rail by analysing the dynamic response of track while the metro train is running. Also, it was converted the measured stress waveform into stress frequency histogram by the rain-flow counting methods, and then accumulated fatigue damage ratio and remaining service life of laid rail were calculated so as the apply the equivalence of stress to S-N curve of a new welded rail. Finally, this study suggests a revision of the periodic replacements criterion of CWR, which was based on accumulated passing tonnage, classified by the types and conditions of track system.

• Journal of dental hygiene science
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• v.13 no.2
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• pp.151-157
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• 2013

The purpose of this study was to examine the toothbrush bristles' wear index and wear rate used by preschool children to provide information on the establishment of criteria for toothbrush replacement cycle for preschool children. One thousand twenty-two toothbrushes were collected from September 20 to November 16, 2012 was analyzed. The findings of the study were as follows: 1. As a result of analyzing the toothbrush wear index, 48.5% of the collected toothbrushes was above 0.400, and the average wear index was $0.421{\pm}0.239$. 2. As a result of analyzing the wear rate of the toothbrushes, score 2 and 3 accounted for 70.4%, and the average wear rate stood at $1.936{\pm}0.848$. 3. As a result of analyzing the state of toothbrush management, the most common average toothbrush replacement cycle was one or two months (63.9%). Concerning the method of toothbrush replacement, the largest group (52.7%) replied they changed toothbrushes based on the abrasivity of toothbrush bristles, and 16.7 percent did that at the request of parents. Given the above-mentioned findings of the study, preschool teachers and parents should be educated to ensure the successful management of preschool children toothbrushes. In addition, it's required to set evident criteria for the right toothbrush replacement cycle for preschool children, and how to provide oral health education in an efficient way should be considered as well.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.19 no.6
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• pp.203-212
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• 2019

Along with the recent fourth industrial revolution, the world's manufacturing powerhouses are pushing for national strategies to revive the sluggish manufacturing industry. Moon Jae-in, the government is in accordance with the trend, called 'advancement of science and technology is leading the fourth round of the Industrial Revolution' strategy. Intelligent information technology such as IoT, Cloud, Big Data, Mobile, and AI, which are key technologies that lead the fourth industrial revolution, is promoting the emergence of new industries such as robots and 3D printing and the smarting of existing major manufacturing industries. Advances in technologies such as smart factories have enabled IoT-based sensing technology to measure various data that could not be collected before, and data generated by each process has also exploded. Thus, this paper uses data generators to generate virtual data that can occur in smart factories, and uses them to analyze the cause of the defect in real time and to predict the replacement cycle of the facility.

• Tunnel and Underground Space
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• v.33 no.6
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• pp.534-546
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• 2023

If the disc cutter is excessively worn or damaged, it becomes incapable of rotating and efficiently cutting rockmass. Therefore, it is important to appropriately manage the replacement cycle of the disc cutter based on its degree of wear. In general, the replacement cycle is determined based on the results of manual inspection. However, the manual measurements has issues related to worker safety and may lead to inaccurate measurement results. For these reasons, some foreign countries are developing the real-time measurement system of disc cutter wear by using different sensors. The ultrasonic sensors, eddy current sensors, magnetic sensors, and others are utilized for measuring the wear amount of disc cutters. In this study, the applicability of eddy current sensors for real-time measurement of wear amount in TBM disc cutters was evaluated. The distance measurement accuracy of the eddy current sensor was assessed through laboratory tests. In particular, the accuracy of eddy-current sensor was evaluated in various environmental conditions within the cutterhead chamber. In addition, the measurement accuracy of the eddy current sensor was validated using a 17-inch disc cutter.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.4
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• pp.311-316
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• 2020

The main cause of DMSMS is the rapid replacement cycle and short life cycle of parts, according to the development of science, compared to the long life cycle of weapons systems. In particular, the problem of the supply and demand of such parts becomes even more acute during the operation maintenance phase after the mass production and power generation stage. To eliminate DMSMS problems that arise continuously from development to the operation of weapon systems and select the most cost-effective countermeasures to obsolescence, this paper suggests a standard to determine the appropriate time for quantitative performance improvement by conducting total life cycle cost analysis. For such purpose, this study examined the domestic and overseas cost analysis methods and applied it to single domestic weapon system to verify the research. This study responds to the issue of discontinuing components and helps reduce the total life cycle cost of military products.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.20 no.44
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• pp.263-271
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• 1997

This paper presents a preventive maintenance model for determining the preventive replacement period of a system in which a failure rate is affected by the cumulative damage of fault and inspection. Especially, the failure rate function is considered to be a function of the cumulative damage of the fault and inspection time. Types of replacement considered are preventive replacement and failure replacement. Failure rate and expected cost function between replacement are derived. An optimal policy is obtained that minimizes the average cost per unit time for preventive replacement, failure replacement, inspection and repair.

• Proceedings of the Korean Reliability Society Conference
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• 2001.06a
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• pp.219-222
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• 2001

제품의 신뢰도 데이터는 새로운 제품의 개발, 제품의 신뢰도 개선, 최적 번인기간의 결정, 보증정책의 결정, 예방교체 또는 정비/수리정책의 결정 등 제품의 수명주기동안의 각종 활동에 필요한 중요한 정보를 제공한다. 여기서는 IEC 300-3-2 의 현장 신뢰성 데이터의 수집에 관한 내용을 중심으로 현장에서 가동되는 아이템의 신뢰도, 가용도, 보전도 및 정비지원과 관련한 데이터의 수집에 관한 지침을 소개하고, 데이터의 수집, 표현, 분석 및 결과와 관련된 주제들을 간단히 살펴본다.