• 제목/요약/키워드: Expected life

검색결과 3,171건 처리시간 0.035초

FMEA에서 주기적인 고장원인 감시하의 기대손실모형에 대한 소고 (Comments on : An Expected Loss Model for FMEA under Periodic Monitoring of Failure Causes)

  • 윤원영;권혁무
    • 대한산업공학회지
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    • 제40권3호
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    • pp.321-324
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    • 2014
  • Kwon et al. (2013) studied the optimal monitoring interval of systems with finite life cycle. It is assumed that there are several failure modes from several failure causes and the occurrence of causes follows a homogeneous Poisson process. The total expected cost is used as an optimization criterion. In this article, we derive newly the total expected cost under the same assumptions and consider some extended models.

중전압 전선의 통계적 수명예측 계산과 응용 방법 (Statistical Life Expectancy Calculation of MV Cables and Application Methods)

  • 조종은;이온유;김상봉;김강식
    • KEPCO Journal on Electric Power and Energy
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    • 제8권2호
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    • pp.61-68
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    • 2022
  • In this paper, the change history of various types of MV (Medium Voltage) cables was investigated. In addition, the statistical life expectancy of each type was calculated by using the operation data and the failure data. For cut-off year, 10 years was applied, and realistically applicable statistical life expectancy was calculated by correcting the cause of failure entered by mistake. The life expectancy of FR-CNCO-W was calculated as 51.2 years, CNCV-W 38.1 years, and CNCV 31.4 years and the overall average is 33.8 years. Currently, the life expectancy of TR CNCV-W is 29.4 years, but it is estimated that the lifespan will be extended if failure data is accumulated. As a result, it is expected that life expectancy results can be applied to Asset Management System (AMS) in the future.

X-65 배관용 재료의 손상해석 (Analysis of Gas Pipelines Damaged in X-65 Steels)

  • 진영준
    • 한국산업융합학회 논문집
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    • 제8권4호
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    • pp.197-204
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    • 2005
  • It is well known that pipelines have the highest capacity and are the safest and least environmentally disruptive form of transporting oil and gas. However, pipeline damages caused by both internal and external corrosion is a major concern threatening the reliability of oil and gas transportation and the soundness of pipeline structure. In this study, we estimated the expected allowable damage defect by comparing the ASTM B31G code which has been developed as the evaluation method of reliability and incident prevention of damaged pipelines based on the amount of loss due to corrosion and the yield strength of materials to a modified theory considering diverse detailed corrosional forms. Furthermore, we suggested the method that estimates the expected life span of used pipelines by utilizing the reliability method based on major variables such as, the depth and length of damage and corrosional rate affecting the life expectancy of pipelines.

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Comparisons of Two-Stage Acceptance Life Test Sampling Plans for Exponential Lifetime Distribution

  • Cho, Ho Sung;Seo, Sun Keun
    • 품질경영학회지
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    • 제20권1호
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    • pp.22-32
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    • 1992
  • This thesis compares life test acceptance sampling plans under lifetime has an exponential distribution. Various practical considerations may lead a user adopt a two-stage, or double sampling, test procedure. Hewett and Spurrier(1983) provided a survey of two-stage methods, as well as examples of experiments for which a two-stage procedure would be appropriate. The plans are compared in terms of the expected number of failures, and the expected time required to reach a dicision. Computational experiments are conducted and the results are tabulated to provide guidelines for selecting an appropriate plan for a given situation.

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유리섬유가 충진된 PTFE 절연재를 채용한 이상용 절연구분장치 개발 (Development of Enhanced Insulator for Section Insulator)

  • 조호령;주종민
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2011년도 제42회 하계학술대회
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    • pp.2173-2174
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    • 2011
  • At the moment, the section insulators for different phases used for over head contact wire system has been all imported since its first application. However, because the section insulators need frequent maintenance and replacement due to the wear by the friction with pantograph and the contamination, which causes its life shorter than as expected, it is required to develop the insulation material with better wear-resistance characteristics and contamination-resistance characteristics. In this thesis, the author developed the section insulator which adopts Teflon tube insulation material which is composed of the Teflon material with the excellent electrical characteristics and wear-resistance characteristics for a longer expected life than that made of conventional FRP.

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부하반환법에 의한 20KVA 비정질 변압기의 경년열화 연구 (Aging Test of 20kVA Amorphous Core Transformer by Loading Back Method)

  • 민복기;송재성;정영호;임정재
    • 대한전기학회논문지
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    • 제43권2호
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    • pp.278-285
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    • 1994
  • Aging test was done by loading back method for 20kVA amorphous core transformers manufactured by Hyosung Industries Co. and korea Electric Power Corporation. Iron losses, copper losses and insulation oil temperatures of the transfromers was measured for all the testing period. Expected life of amorphous core transformers on the basis of the degradation of the insulators was 46 years at 100% load, and 2.4 years at 130% load. Average temperature rising of transformer oil of amorphous core transformers was higher than that of silicon steel core transformers. Hence lowering the oil temperature by optimized design is needed for improving the expected life of the amorphous transformers.

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The Software Reliability Growth Models for Software Life-Cycle Based on NHPP

  • Nam, Kyung-H.;Kim, Do-Hoon
    • 응용통계연구
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    • 제23권3호
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    • pp.573-584
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    • 2010
  • This paper considers the differences in the software execution environments in the testing phase and the operational phase to determine the optimal release time and warranty period of software systems. We formulate equations for the total expected software cost until the end of the software life cycle based on the NHPP. In addition, we derive the optimal release time that minimizes the total expected software cost for an imperfect debugging software reliability model. Finally, we analyze the sensitivity of the optimal testing and maintenance design related to variation of the cost model parameters based on the fault data observed in the actual testing process, and discuss the quantitative properties of the proposed model.

강상자형교의 생애주기비용 최적설계 (Life-Cycle Cost Optimization for Steel Box Girder Bridges)

  • 조효남;민대홍;권우성;정기영
    • 한국전산구조공학회:학술대회논문집
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    • 한국전산구조공학회 2001년도 봄 학술발표회 논문집
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    • pp.128-136
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    • 2001
  • This paper presents an optimum deck and girder system design for minimizing the life-cycle cost (LU) of steel box girder bridges. The problem of optimum LCC design of steel box girder bridges is formulated as that of minimization of the expected total LCC that consists of initial cost, maintenance cost, expected retrofit costs for strength, deflection, and crack. To demonstrate the effect of LCC optimum design of steel box girder bridges, the LCC optimum design is compared with conventional design method for steel box girder bridges design. From the numerical investigations, it may be positively stated that the optimum design of steel box girder bridges based on LCC will lead to more rational, economical and safer design.

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노인 홈 케어를위한 CNN 기반의 비정상 인간 활동 인식 시스템 (Abnormal Human Activity Recognition System Based on CNN For Elderly Home Care)

  • 아레주;이효종
    • 한국정보처리학회:학술대회논문집
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    • 한국정보처리학회 2019년도 춘계학술발표대회
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    • pp.542-544
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    • 2019
  • Changes in a person's health affect one's lifestyle and work activities. According to the World Health Organization (WHO), abnormal activity is growing faster in people aged 60 or more than any other age group in almost every country. This trend steadily continues and expected to increase further in the near future. Abnormal activity put these people at high risk of expected incidents since most of these people live alone. Human abnormal activity analysis is a challenging, useful and interesting problem among the researchers and its particularly crucial task in life and health care areas. In this paper, we discuss the problem of abnormal activities of old people lives alone at home. We propose Convolutional Neural Network (CNN) based model to detect the abnormal behaviors of elderlies by utilizing six simulated action data from daily life actions.

대퇴경부 골절 환자의 입원 생활 (The Hospital Life of the Patient with Femoral Neck Fracture)

  • 김경자;지성애
    • 간호행정학회지
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    • 제2권1호
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    • pp.35-56
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    • 1996
  • Nowerdays, the increase of traffic accidents and old age population make the Femoral Neck Fracture(FNF) patients increase. By the improvement of education and standard of living the patients demand better medical service than before. This study is designed to give practical help for the FNF patients by observing their hospital life and establish practical nursing strategies for the FNF patients. For these purposes the Ethnographic Participant Observation was adopted. By this study is focused on the hospital life patient's view. For this end, the field study adopted orthopedic ward in the C University Hospital with 400 beds in Seoul. The object patients of the study were twelve patients. The patients experienced five stages : Embarrassment, Conflict, Stability, Independent, and Extension Stage. The findings and prepared nursing strategies are stated as follows. First, in the Embarrassment Stage they suffered embarrassment, anxiety, pain, they could not do ordinary things. The patients who accidental fractures had anxiety from unfamiliar tests and from hospitalization itself. They lamented that they could not ordinary things, and do nothing but obeying the hospital, and endure the pain. They recognized the changed environment and resigned themselves to life in the ward. In this stage, full openness by the nurses is needed. Second, the attribute of the Conflict Stage were conflict, fear, curiosity, belief, reflection. When they sign the consentment form, they experience conflicts about the possibility of complication, fear of recovery from anesthesia, curiosity about the operation procedure, post - operation state, reflection on their past life, and promise to care for their family members after discharge and keep their religious life faithfully. And they accepted the operation depending on God, believing in modern medicine, and the surgeon. Asking for their changed informations, they expected positive results from the operation. In this stage, an empathic attitude by the nurses is needed. Third, the attribute of the Stability Stage were relief, gratitude, difficulty with excretion, and pain. When they awoke from anesthesia, they felt relief because of a the end of the operation, but they experienced extreme pain, difficulty of excretion in bed. They accepted the changed environment and expected recovery. In this stage, support by the nurses is needed. Fourth, the attributes of the Independence Stage were freedom, exercise, nurturing, anxiety, and discomfort. When they ambulated and exercised, they experienced freedom. They showed exhibited weakness of the digestive organs and discomfort hospital's space, structure, and facilities, the delay of medical certificate issue the lack of prompt response by the medical agents. They ate nurturious food and felt anxiety on the end of hospital life and returning to their ordinary life. They showed the independence of overcoming their environment by increasing exercise and expected their discharges. In this stage, respect by the nurses is needed for the patients to, overcome their environment and prepare for their independence. Fifth, the attributes of the Extension Stage were pessimism, isolation, dissatisfaction, and pain. Accompanied injury and old age made their ward life extend to over seven weeks. They exhibited weariness, melancholy, skeptisis, general pessimistic feeling, and desperation caused by their isolated life. They experienced the digestive discomfort caused by the prolonged medication and psycological pain caused by long-time hospitalization. As a, result, their dissatisfaction on the human, physical, and systematic environments had been increased. They acquired critical power and sought for something to do spending their time. They expected vaguely about the returning of their ordinary life. In this stage, counseling is needed by the nurse to overcome positively their psychological, social, and physical problems. The process of the FNF patient's ward life starts from the dependent state, when they are hospitalized, and gradually progresses to self-fulfillment in order to keep independent life. As a result, the FNF patients showed "Response in Challenge" or "Adaptation in Conflict" through their experiences of social, physical, and psychological difficulties.

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