• 한국항해항만학회지
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• 제30권6호
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• pp.525-531
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• 2006

항만에 있어서 하역장비는 매우 중요하다. 컨테이너 크레인이나 트랜스퍼 크레인 같은 장비가 고장이 나면 수리나 예비품의 재주문에 걸리는 시간동안 작업이 이루어지지 못하므로 엄청난 비용손실을 초래한다. 그러나 가격이 고가이므로 예비품을 많이 보유할 수도 없는 형편이다. 대체적으로 부피가 크고 고가인 항만 장비의 특성상 효율적인 예방정비와 고장 분석을 통해 장비의 신뢰성을 확보하는 것이 무엇보다 필요하다. 본 연구는 항만 장비 중 주요 장비인 트랜스퍼 크레인을 선정하여 시스템 및 기능, 고장 메카니즘을 분석하였으며, 고장/정비 이력 데이터의 수집 및 정리를 통하여 고장과 정비 작업의 내용을 표준화하였다. 장비의 운영 및 정비 작업을 전산화하기 위한 기초 작업인 본 연구는 다음 세대 장비의 최적 설계와 장비의 최적 운영 정책을 설계하는 새로운 시도가 될 것이다.

• Korean Chemical Engineering Research
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• 제43권5호
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• pp.571-578
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• 2005

불연속 화학공정은 소비자 수요에 탄력성 있게 대처할 수 있는 장점이 있는 반면에 그 특유의 동특성 때문에 복잡하고, 계획된 조업 시간과 실제 조업 시간 사이에서 외란(disruption) 또는 불확실 변수(uncertainty)에 의한 차이가 자주 발생하는 단점이 있다. 이에, 본 논문에서는 예측 생산계획(predictive scheduling)에 의해 결정된 생산계획에서 미래에 발생하는 공정 변수 값의 변화를 실시간으로 예측 생산계획을 수정, 제시하여 주는 생산 계획 시스템인 동적 생산계획(reactive scheduling) 기법을 개발하였다. 불확실 인자를 고려한 동적 생산계획에서, 본 논문에서는 장치 이상(equipment failure)이 발생하였을 때 공정 운전조건의 변화를 실시간으로 반영하여, 예측 생산계획(predictive scheduling) 모델에 의하여 제시된 전체 생산 계획을 최대한 유지하고 공정 변수의 변화를 실시간으로 반영하기 위하여 right shift rescheduling과 total regeneration 기법을 사용하였다. 또한, 불확실 인자의 발생 전후의 predictive scheduling과 reactive scheduling 간의 변화 정도를 측정하는 수단인 schedule stability 위하여, 본 논문에서는 수정된 sequence deviation과 percentage change in makespan을 사용하여 제안된 동적 생산계획의 안정성을 측정하였다. 본 논문에서 제안한 동적 생산계획 시스템은 기존에 제시되었던 경험 법칙에 의한 결과값에 비해 좋은 결과를 보여주었다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 하계학술대회 논문집 Vol.8
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• pp.525-526
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• 2007

Continuous on-line temperature monitoring provides the means to evaluate current condition of equipment and detect abnormality. It allows corrective measures to be taken to prevent upcoming failure. Continuous temperature monitoring and event recording provides information on the energized equipment's response to normal and emergency conditions. On-line temperature monitoring helps to coordinate equipment specifications and ratings, determine the real limits of the monitored equipment and optimize facility operations. Using wireless technique eliminates any need for special cables and wires with lower installation costs if compared to other types of online condition monitoring equipment. In addition, wireless temperature monitoring works well under difficult conditions in strategically important locations. Wireless technology for on-line condition monitoring of energized equipment is applicable both as standalone system and with an interface with power quality monitoring system.

• 한국군사과학기술학회지
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• 제21권5호
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• pp.607-613
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• 2018

Hydraulic systems are widely used in the field of defense, construction machinery, agricultural machinery, and general industries, due to various advantages such as quick response speed and precision control. The defense equipments such as light rescue vehicle is operated in very harsh environments, so hydraulic components used in defense equipment are required to have very high reliability. In particular, hydraulic piston pump is very important component in a hydraulic systems, so life prediction of pump is essential. Therefore, in this study, we analyze the potential failure and the main failure mode of the hydraulic piston pump for the light rescue vehicle through the FMEA analysis, and predict the life of the pump by the accelerated life test considering the usage conditions.

• 산업경영시스템학회지
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• 제37권3호
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• pp.16-23
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• 2014

Most of metal cutting and processing companies are going through the difficulties such as frequent downtime and high failure rates by missing times to replace parts of CNC equipment. The reason is that the correct operation times of expensive CNC equipment can't be calculated. In this paper, to solve this problem, we try to construct the intelligent production information system for a case company and analyze its expected effects. The effects are as follows. First, it saves money about 3 million won each year during the useful life of three years by reducing downtime and failure rates, and increasing production rates etc. Second, it makes easily find and fix the cause of faulty through traceability of the production process, and enables to perform a systematic facility management through the calculation of reliable equipment's overall efficiency. This case can be easily applied in similar industries, and will contribute greatly to enhancing the competitiveness of related industries.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 춘계학술대회 논문집
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• pp.1168-1173
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• 2007

The Seoul Subway is one of the most heavily used Subway System in the world. It provides reliable transportation services, conveys nearly 4 million Passengers across 117 subway stations with a length of 134.9 Km. Over the years the safety for the Subway has been a major concern, trains going off the track, equipment failure, careless operation, Signal failure are increasing day by day. In a Recent Public opinion 40% said the causes to above facts are Vehicle breakdown because of Operators, Old rail defect, Quality of material. 20% of the opinion said the obstacles were because of Operation, crew carelessness, negligence in signal operation. In case of any accident the crew members cannot resolve the issue on site (Aid insufficiency), because of lack of knowledge and carelessness. The main obstacles for Subway are vehicle breakdown, Electric equipment failure, Signal Equipment failure, and Crew carelessness. This paper aims to provide major problems which are needed to be solved as quickly as possible for citizen's safety for a comfortable subway system making a comfortable ride and providing better service gradually.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2017년도 춘계학술대회
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• pp.383-386
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• 2017

임베디드 시스템의 일종인 항공전자 장비는 높은 안전성과 신뢰도를 요구한다. 항공전자 장비 고장은 항공기 운용에 중대한 영향을 미칠 뿐만 아니라 최악의 경우에는 조종사와 승객의 인명 손실을 초래할 수도 있다. 본 논문에서는 항공전자 장비의 신뢰도를 높이기 위해 장비에 발생 가능한 고장을 사전에 감지할 수 있는 Built-In-Test(이하: BIT) 설계 기법과 장비의 Mean Time Between Failure(이하: MTBF)를 향상시킬 수 있는 설계 방법을 연구하고 실제 항공전자 장비에 적용하여 신뢰도를 향상시킨 사례를 소개한다.

• Journal of Electrical Engineering and Technology
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• 제9권3호
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• pp.957-963
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• 2014

Converter transformers play important roles in high-voltage direct current transmission systems. This paper presents experimental and analysis results of the combined electrical and thermal aging of oil-impregnated paper at pulsating DC voltages. Breakdown voltages and time-to-breakdown of oil-paper specimens were measured by using short-time and constant-stress tests. The breakdown characteristics of combined electrical and thermal aging on insulation system were discussed. According to the relationship between failure time and aging temperature, the two-parameter Weibull model was improved. On the basis of the competing risk algorithm and the improved Weibull model, the two factors failure model was calculated. And the influence of temperature in the insulation system has been analyzed. This model performs better than the two-parameter Weibull model when both time and temperature are considered as variables in estimating the lifetime of oil-paper insulation.

• 드라이브 ㆍ 컨트롤
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• 제15권4호
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• pp.48-54
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• 2018

The hydraulic servo actuator has always operated very precisely with high frequency and small displacement, and is used continuously for a long time. The hydraulic servo actuator of the test equipment used in the accelerated life test in order to guarantee the service life of the automotive parts failed earlier than the products before finishing the test. This study performed an analysis on the cause of the failure of the hydraulic servo actuator used in the test equipment, changed the design of the actuator to solve the root cause of the main failure mode, and developed the improved servo actuator. Based on above process, this study established a better performances and longer lifetime of the servo actuator after testing.

• 한국경영과학회:학술대회논문집
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• 한국경영과학회 2006년도 추계학술대회
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• pp.618-629
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• 2006

This Paper is about optimizing preventive maintenance period of connected (r,s) out of(m,n) : F lattice system that one of multi-component system, (m,n) matrix failure of whole system is occurrence when parts that belong in (r,s) matrix part procession of parts arranged with procession are breakdown all. The preventive maintenance about system is very important viewing from system reliability and operational expense viewpoint. Preventive maintenance that misses a time calls big loss by system failure and expense of frequent full equipment is paid excessively in preventive maintenance itself but expense is paid much in preventive maintenance itself and whole expense escalation can be achieved preferably. Through this research, reliability model is constructed that do expense by smallest under full equipment policy chosen through comparison of each full equipment policy and preventive maintenance expense full equipment cycle and r ,s value are made using simulated annealing algorithm and simulated annealing algorithm that converge fast in multi-component system certified most suitable to optimization decision