• 한국경영과학회:학술대회논문집
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• 대한산업공학회/한국경영과학회 2000년도 춘계공동학술대회 논문집
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• pp.469-472
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• 2000

Replacement policy of a degradation of system is investigated by incorporating the loss function defined by the deviation of the value of quality characteristic from its target value, which determines the loss cost . Two cost minimization problems are formulated : 1)determination of an optimal inspection period given the state for the replacement and 2)determination of an optimal state for replacement under fixed inspect ion period. Simulation analysis is performed to observe the variation of total cost with respect to the variation of the parameters of loss function, inspection cost, respectively. As a result, parameters of loss function are seen to be the most sensitive to the total cost. On the contrary, inspect ion cost is observed to be insensitive.

• 한국신뢰성학회:학술대회논문집
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• 한국신뢰성학회 2000년도 추계학술대회
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• pp.329-333
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• 2000

Delay time analysis is a pragmatic mathematical concept readily embraced by engineers which has been developed as a means to model maintenance decision problem. This paper considers an inspection period using delay time analysis for fishing vessel equipment. We assume that delay time distribution is Weibull and inspections are perfect. In this paper, we determine the optimal inspection period which minimize the expected downtime per unit time.

• 열처리공학회지
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• 제13권1호
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• pp.16-20
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• 2000

There have been little reports on the degradation of medium-carbon steel tubes served at high temperature for a long period. The purpose of this research was to provide the information of the proper replacement span of the tubes with the new ones. We investigated the medium-carbon steel tubes which were used at petrochemical plant for about 50,000 hrs to examine their mechanical properties and microstructures. Experimental results showed that the tubes satisfied the specification of ASTM despite such a long period of service, but mechanical properties, especially charpy impact values, were reduced. It concludes that the tubes on service at the plants needs a periodical inspection.

• Smart Structures and Systems
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• 제25권6호
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• pp.733-749
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• 2020

This study presents a computer vision-based approach for representing time evolution of structural damages leveraging a database of inspection images. Spatially incoherent but temporally sorted archival images captured by robotic cameras are exploited to represent the damage evolution over a long period of time. An access to a sequence of time-stamped inspection data recording the damage growth dynamics is premised to this end. Identification of a structural defect in the most recent inspection data set triggers an exhaustive search into the images collected during the previous inspections looking for correspondences based on spatial proximity. This is followed by a view synthesis from multiple candidate images resulting in a single reconstruction for each inspection round. Cracks on concrete surface are used as a case study to demonstrate the feasibility of this approach. Once the chronology is established, the damage severity is quantified at various levels of time scale documenting its progression through time. The proposed scheme enables the prediction of damage severity at a future point in time providing a scope for preemptive measures against imminent structural failure. On the whole, it is believed that the present study will immensely benefit the structural inspectors by introducing the time dimension into the autonomous condition assessment pipeline.

• 항공우주시스템공학회지
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• 제15권1호
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• pp.63-71
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• 2021

한국해군은 1978년에 하푼 유도탄을 최초 도입 후 단계적인 획득을 통하여 현재까지 운용하고 있다. 하푼 유도탄을 장기 운용함에 따라 성능보장을 위한 적극적인 후속 군수지원이 필요하며, 유도탄 검사는 유도탄 상태를 확인하기 위한 기본 활동이다. 본 연구는 장기간 운용 중인 하푼 유도탄의 기존 검사주기가 적절한지 확인하기 위하여 수행되었으며, 연구 방법은 해군의 야전운용자료를 바탕으로 Martinez 이론과 비모수적 MCF 기법을 활용하여 운용 기간에 따른 구간별 검사주기를 분석하여 제시하였다.

• 한국건설관리학회논문집
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• 제20권2호
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• pp.13-27
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• 2019

가설공사는 임시시설물이지만 공사기간동안 사용빈도가 높으며 공사비의 10% 내외를 차지하고 있어 체계적인 관리가 필요하다. 하지만 가설공사의 시공검측정보들은 설계도서 및 시방사항에 특별한 명시가 없는 경우가 많으며 제기준에 대한 사항도 방대하다. 이로 인해 가설공사에 대하여 품질점검을 실시할 경우 관련 점검업무들을 비효율적으로 수행하며, 인간적인 오류가 발생할 확률이 높다. 따라서 본 연구에서는 가설공사에 대하여 품질점검 업무수행을 지원하고 관련 정보를 제공할 수 있는 전자작업지원시스템을 적용하고자 한다. 이를 위해 IDEF0를 활용하여 업무 단위프로세스별 정보흐름을 규명하고 EPSS기반 품질점검 업무체계를 정리하여 프로토타입을 개발한다. 이후 현장적용을 통한 검증방법으로 가설공사 품질점검 업무의 효율과 정보접근성을 향상하고자 한다.

• 한국구조물진단유지관리공학회 논문집
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• 제7권2호
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• pp.135-140
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• 2003

As a construction technique is developed recently, the construction space and construction period are considered to important matters. Especially, in case of construction period, several method is proposed for strength control in the construction field. However there are very little strength control models for application of internal condition. The purpose of this study is to develop a strength control model for application of variety internal condition at construction field. The results are as follows ; 1) According to the results of compressive strength of concrete evaluated by logistic curve and proposed curve, proposed curve is applicable of construction field because there is similar relation with logistic curve. 2) It is shown that the construction period is shortened by reduction of the formwork removal time, because a predicted compressive strength of using the new curve is higher than the proposed compressive strength of standard.

• 농약과학회지
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• 제16권3호
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• pp.195-201
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• 2012

본 연구는 경기도에서 유통 중인 수입과실류에 대한 잔류농약 분석을 수행하였다. 총 22품목 124건의 시료를 구입하여 GC/NPD-ECD, TOF/MS, UPLC/PDA 및 HPLC/FLD, LC/MS/MS를 이용하여 218종 잔류농약을 동시 다성분 분석법으로 분석한 결과 18건의 과실에서 잔류농약이 0.003~0.3 mg/kg 범위로 검출되었으나 기준초과 시료는 없었다. 과실의 부위별 특성에 따른 잔류농약정도를 알아보기 위해 농약이 검출된 과실류 중 14건에 대하여 분리 실험을 실시하였으며, 그 결과 과피 14건에서 0.03~1.5 mg/kg, 과육의 경우 2건에서 검출한계 미만으로 나타났다. 실험결과 모두 잔류농약허용기준 이내에서 검출되어 정상적인 방법으로 섭취할 경우 위해도는 매우 낮은 수준이었다. 그러나 미량이라도 장기간 섭취시 인체에 유해할 수 있으며, 검출빈도가 높은 성분들이 검출되므로 수입과실에 대한 지속적이고 체계적인 모니터링이 필요하겠다.

• 한국건축시공학회지
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• 제13권3호
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• pp.209-217
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• 2013

The execution of a construction project involves the engagement of many participants. Generally, the Authority uses CM to certify that the Work is built according to the contract documents. The CM work scope is expressed in the Construction Technology Management Act and its Regulation. The mandated and delegated CM services are limited to the construction period. If Contractor is required to repair a construction defect, the Contractor should bear the burden of the inspection service for the defect repair, because it is associated with him. Nevertheless, CM should submit a bond to provide the inspection and supervision service for the defect repair. These may result in conflict with each liability. Therefore, CM service in the law and regulation was investigated and analyzed in this study to classify the characteristics of CM contracts, and it was suggested that the CM liability for the inspection and supervision service for the defect repair should be reconsidered.

• 한국압력기기공학회 논문집
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• 제10권1호
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• pp.20-24
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• 2014

Recently, it is getting more and more important ensuring the integrity for the equipment degradation according to the increase of nuclear power plant operating period. In many equipment of the nuclear power plant, snubbers mainly installed in reactor coolant pumps, steam generators and piping protected the equipment and piping from the occurrence of transient dynamic loads such as the earthquake, thermal load during the plant operation. This report describes the function, regulation, inspection requirements and management status of the snubbers installed in domestic nuclear power plants.