• 아시안잔디학회지
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• 제12권4호
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• pp.195-202
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• 1998

The development of a protocol for high efficiency of embryogenic callus separation, maintenance and plant regeneration from the seeds of zoysiagrass cv. Zenith was studied. Embryogenic callus ratio is absolutely determined by genotype, but by adding high concentration of copper into medium, changing light condition and maintaining callus on initial induction medium for 8∼10 weeks, embryogenic callus can be easily distinguished and its growth can be promoted. There were significant differences among selected callus lines (each from one seed) according to their growth rates and regeneration percentages. Callus pre-treatment with activated charcoal inhibited callus growth, increased the level of precocious germination during culture and promoted shoot cluster formation after transfer to regeneration medium. For long-term callus maintenance, N6AA medium was better than MS medium, because the former inhibited non-embryogenic callus formation and kept vigor of embryogenic callus. The best callus lines Z-(5) has been successfully used for transformation and somaclonal variation selection in our laboratory.

• 한국철도학회논문집
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• 제7권4호
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• pp.406-411
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• 2004

BOM(Bill of Materials) is a listing or description of raw materials, parts, and assemblies that define a product. In order to evaluate the performance of proposed BOM management system, which is very important to maintenance information system of urban transit. We develop component based BOM data and rule-set to design data structure that is mutually independent and integrated efficiently. It divides data whit management interface using component technology. The component based master BOM have advantage in database size and flexibility. Flexibility is measured as the number of updating records in accordance with added new product or engineering change. In database size, component based BOM is the best. we develop master BOM management system in web environment.

• 한국산학기술학회논문지
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• 제12권8호
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• pp.3785-3793
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• 2011

본 연구에서는 상업용 임대건물을 대상으로 사용자, 소유자, 관리자 3자와 이들 3면에 발생되는 권리와 의무, 급부와 반대급부에서 나타나는 문제점과 이들을 둘러싼 법과 제도의 문제점을 문헌조사와 전문가 인터뷰 그리고 현장의 설문조사를 통하여 건물관리 제도의 총체적 문제점을 도출하고자 하였다. 현재와 같이 급변하는 시대에 각 분야에서 그들의 다양성에 맞도록 각종 개선을 요구하지만 제한된 시간과 인력 그리고 예산 등의 이유로 최선의 개선에 따른 우선순위는 능률적이고 경제적 지출을 필요로 하는 중요한 사안이다. 이에 본 연구에서는 도출된 문제점에서 BSC관점으로 평가요소를 추출하고 추출된 평가요소에 AHP 기법을 활용하여 가중치를 구한 후 가중치 적용 전 후를 비교 평가하여 중요도를 정함으로써 3자3면을 위한 효과적인 대안과 합리적 지출을 실현할 수 있게 된다. 이로서 향후 건물기능의 스마트화 및 가치의 극대화, 사용자 편익이 보장되는 건물관리제도가 현실화되는 계기를 마련하고자 한다.

• 항공우주시스템공학회지
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• 제10권4호
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• pp.67-74
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• 2016

한국형 상태기준정비는 현재 한국해군 함정에 설치된 ICAS를 최대한 활용하여 전투준비태세를 완비하고, 선제적 정비/보급 지원과 군수자산의 경제적 운용, 데이터 기반 장비수명관리를 위한 것이다. 이러한 목적을 달성하기 위해서는 장비상태의 기준을 설정해야 하는데 이는 제작사에서 원천적인 기술을 제공하고 있지 않아 각 장비별 성능 맵 확보가 필요하고 고장패턴 등의 자료 축적이 필요하다. 본 연구에서는 소형 가스터빈엔진을 활용하여 가스터빈 성능 맵을 확인하고 고장정보를 축적하여 실시간으로 장비성능 확인과 성능 경향을 나타내게 하였고 이를 통해 운용자의 행동지침과 정비자의 검사 절차등을 명시하여 최적의 장비상태가 유지 될 수 있도록 솔루션을 개발하였다. 본 연구를 기반으로 실제 함정의 데이터를 이용한 상태진단기법 발전에 활용할 예정이다.

• 산업경영시스템학회지
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• 제40권1호
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• pp.57-64
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• 2017

In order to reduce damages to major railroad components, which have the potential to cause interruptions to railroad services and safety accidents and to generate unnecessary maintenance costs, the development of rolling stock maintenance technology is switching from preventive maintenance based on the inspection period to predictive maintenance technology, led by advanced countries. Furthermore, to enhance trust in accordance with the speedup of system and reduce maintenances cost simultaneously, the demand for fault diagnosis and prognostic health management technology is increasing. The objective of this paper is to propose a highly reliable learning model using various machine learning algorithms that can be applied to critical rolling stock components. This paper presents a model for railway rolling stock component fault diagnosis and conducts a mechanical failure diagnosis of motor components by applying the machine learning technique in order to ensure efficient maintenance support along with a data preprocessing plan for component fault diagnosis. This paper first defines a failure diagnosis model for rolling stock components. Function-based algorithms ANFIS and SMO were used as machine learning techniques for generating the failure diagnosis model. Two tree-based algorithms, RadomForest and CART, were also employed. In order to evaluate the performance of the algorithms to be used for diagnosing failures in motors as a critical railroad component, an experiment was carried out on 2 data sets with different classes (includes 6 classes and 3 class levels). According to the results of the experiment, the random forest algorithm, a tree-based machine learning technique, showed the best performance.

• 정보과학회 컴퓨팅의 실제 논문지
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• 제23권1호
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• pp.1-12
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• 2017

예방정비는 대규모 산업시설에서 설비의 성능을 최적으로 유지하는 활동을 의미하며, 궁극적으로 고장을 미연에 방지하여 생산 효율을 극대화하는 것을 목적으로 한다. 일반적으로 인력에 의한 주기적인 정비가 이루어지지만, 지속적으로 발생하는 고장을 방지할 수 없는 문제가 있다. 또한, 문제를 조기에 해결하기 위한 고장에 대한 조치는 설비 전문가에 의존하기 때문에, 전문가의 부재 상황이나 미숙련된 전문가에 의한 진단 오류로 인한 대응의 한계가 있다. 인력에 의존한 설비 진단과 문제의 조기 발견을 돕기위해 알람 시스템이 활용되고 있지만, 단순 정보 수집을 위해 설계되고, 방대하게 알람을 발생시키므로 실제적인 효용성이 없다. 본 논문에서는 시스템에 의한 고장징후 포착과 문제의 원인 및 향후 발생할 문제를 파악하기 위해서, 전문가의 경험지식을 시스템 지식으로 구축을 통한 자동화된 예방정비시스템을 설계 및 개발하였으며, 전문가 지식을 재이용하기 위한 시스템의 구조와 활용 방안에 대해서 논한다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 제40회 하계학술대회
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• pp.686_687
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• 2009

The traceability maintenance system for the AC voltage and current has been developed at the frequency range of 20 Hz to 100 Hz without using any compensation technique which is used at thermal converter (TC) ac-dc transfer system at low frequencies. The system uses a digital voltmeter (DVM) as a data acquisition system of the input waveform and stored data in memory. The developed algorithm acquires and processes the sampling data to calculate the root mean square (rms) value of the input voltage of DVM which operates at DC 10 V range for better accuracy. The best uncertainty of the AC voltage measurements is $3 {\mu}V/V$ within the frequency range. The best uncertainty of the AC current measurements is better than the $5 {\mu}A/A$ and mainly depend on the current to voltage converter, ac-dc current shunt or Current Transformer (CT), used for the measurement

• 건설안전기술
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• 통권52호
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• pp.58-66
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• 2011

This study presents an algorithm to select the best alternative plane among various bridge superstructure types (Steel box girder, Rational girder, PSC-I girder) using Value Engineering (VE). Economical efficiency, landscape, constructability, maintenance, stability, function of bridge superstructure were taken into consideration in the designing of bridge. Economical efficiency was evaluated for each alternative plan with optimal design considering Life Cycle Cost (LCC), Repair and rehabilitation histories and some factors were set to get reasonable results. In the application of Analytic Hierarchy Process (AHP), consistency of Pairwise Comparisons Matrix was evaluated and the best plan was determined.

• International Journal of Railway
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• 제6권2호
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• pp.45-52
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• 2013

Railway construction needs vast soil investigation for its infrastructure foundation designs along the planned railway path to identify the design parameters for stability and serviceability checks. The soil investigation data are usually classified and grouped to decide design input parameters per each construction section and budget estimates. Deterministic design method which most civil engineer and practitioner are familiar with has a clear limitation in construction/maintenance budget control, and occasionally produced overdesigned or unsafe design problems. Instead of using a batch type analysis with predetermined input parameters, data population collected from site soil investigation and design load condition can be statistically estimated for the mean and variance to present the feature of data distribution and optimized with a best fitting probability function. Probabilistic approach using entire feature of design input data enables to predict the worst, best and most probable cases based on identified ranges of soil and load data, which will help railway designer select construction method to save the time and cost. This paper introduces two Monte Carlo simulations actually applied on estimation of retaining wall external stability and long term settlement of organic soil in soil investigation area for a recent high speed railway project.

• 한국안전학회지
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• 제24권6호
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• pp.79-85
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• 2009

This study presents an algorithm to select the best alternative plane among various bridge superstructure types(Steel box girder, Rational girder, PSC-I girder) using Value Engineering(VE). Economical efficiency, landscape, constructability, maintenance, stability, function of bridge superstructure were taken into consideration in the designing of bridge. Economical efficiency was evaluated for each alternative plan with optimal design considering Life Cycle Cost(LCC). Repair and rehabilitation histories and some factors were set to get reasonable results. In the application of Analytic Hierarchy Process(AHP), consistency of Pairwise Comparisons Matrix was evaluated and the best plan was determined.