• 제목/요약/키워드: life-time use

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무한 평면체에 존재하는 복수 표면균열의 성장에 대한 수명예측용 시뮬레이션 개발에 관한 연구 (A Program Development of Life Prediction Simulation for Multi-Surface Cracks on the Finite Plate)

  • 황남성;서창민;남승훈
    • 한국해양공학회지
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    • 제11권4호
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    • pp.61-75
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    • 1997
  • The social demand urges us to use some equipments and structures in high temperature environment. By this occasion, the necessity of studying the fatigue crack growth is an important aspect of new materials. However, the present situation is rarely to accumulate the fatigue data. Especially, 1Cr-1Mo-0.25V steel and 304 stainless steel have been increased to be used under the severe condition of high temperature. And so, the fatigue estimation of those materials is important and appropriate. Fatigue tests have been carried out to examine the crack initiation, growth behaviour for the small fatigue crack of 1Cr-1Mo-0.25V steel and 304 stainless steel at room temperature and 538^{\circ}C$. The remote measurement system which has many merits of checking and saving the image for detailed examination was applied to closely detect the crack length. Generally, the fatigue crack initiated in the form of multiple cracks and grew each other. And then it coalesced to become a major crack. The major crack governed the rest of the fatigue life. In the growing process, each peripheral cracks interact and grow for a certain period. After then, it coalesced and fractured. On the basis of the above experimental data for the small crack, a simulation program was developed to predict the residual life time and to estimate the integrity of machine elements and structures. At the same time, the simulation was extended to 1Cr-1Mo-0.25V steel. The simulation results have shown a good agreement to those of the experimental ones for both materials of 1Cr-1Mo-0.25V steel and 304 stainless steel with small cracks. The NASCRAC has applied to compare the fatigue life with the experimental results. And so, it can be said that the simulation program is valuable tools to the industrial fields.

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한.중.일 중학생의 생활양식 비교 및 생활양식이 주관적 건강에 미치는 영향 (The Factors Influencing Perceived Health: A Comparison of Life Styles in Korean, Chinese and Japanese Adolescents)

  • 최은희;남은우;이규식;진기남
    • 한국학교ㆍ지역보건교육학회지
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    • 제11권2호
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    • pp.1-12
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    • 2010
  • Objectives: This study examined the life style differences of middle school students among in Korea, China and Japan and analyzed the factors influencing on the perceived health. Methods: The data of 1,390 students aged between 14 years and 16 from three countries collected between in November, 2008 and January, 2009 and analyzed the data using $x^2$-test, ANOVA-test and logistic regression analysis in SPSS Win 12.0. Results: Korean students spent more time on study and mobile phone use than Japanese, and more time on TV computer game than Chinese students. In addition, Korean students had a higher percentage in skipping breakfast and in not exercising than the other two countries. Overall, students who went to bed before midnight, having breakfast or doing exercise had better perceived health. Conclusions: The policies on health education should be conducted at a national level in order to improve their unhealthy life styles of Korean middle school students.

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항공엔진 열화데이터 기반 잔여수명 예측력 향상을 위한 데이터 전처리 방법 연구 (A study on Data Preprocessing for Developing Remaining Useful Life Predictions based on Stochastic Degradation Models Using Air Craft Engine Data)

  • 윤연아;정진형;임준형;장태우;김용수
    • 산업경영시스템학회지
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    • 제43권2호
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    • pp.48-55
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    • 2020
  • Recently, a study of prognosis and health management (PHM) was conducted to diagnose failure and predict the life of air craft engine parts using sensor data. PHM is a framework that provides individualized solutions for managing system health. This study predicted the remaining useful life (RUL) of aeroengine using degradation data collected by sensors provided by the IEEE 2008 PHM Conference Challenge. There are 218 engine sensor data that has initial wear and production deviations. It was difficult to determine the characteristics of the engine parts since the system and domain-specific information was not provided. Each engine has a different cycle, making it difficult to use time series models. Therefore, this analysis was performed using machine learning algorithms rather than statistical time series models. The machine learning algorithms used were a random forest, gradient boost tree analysis and XG boost. A sliding window was applied to develop RUL predictions. We compared model performance before and after applying the sliding window, and proposed a data preprocessing method to develop RUL predictions. The model was evaluated by R-square scores and root mean squares error (RMSE). It was shown that the XG boost model of the random split method using the sliding window preprocessing approach has the best predictive performance.

공연분석: 오스터마이어의 <햄릿> (프랑스 2008, 한국 2010) (Performance Analysis of Ostermeier's Hamlet)

  • 이인순
    • 한국연극학
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    • 제52호
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    • pp.229-270
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    • 2014
  • Ostermeier's Hamlet has no particular contemporary reinterpretation. Alternately devoting to show retrospect in illusion and existence through revenging actions. However, Shakespeare's metaphorical and implicative language is dissipated and the style of the play is not an illusive space-time, but a tragic theatrical production that uses rough language to express the depth of the story. The Perfomance of Hamlet is a sensuous jumble up of a diverse range of mass media. The double roles that the actors carry out give an affect of isolation between the audience and the play itself showing both empathy and liberty. Ostermeier's Hamlet distinctively shows a post-modern performance through the prominent elements of dirt, the use of mixed genre, theatric emphasis, making an image and the fulfillment of acting. Nonetheless, Ostermeier's performance stays off the point on the breakup strategy of the post-modern drama without suspending the narrative of Shakespeare's Hamlet. Besides aiming to show a performance centered by the imagery of physical expression, his performance shows New Realism in the 1960's, showing everyday life. Ostermeier thinks, that theatre helps give contemporary people an accurate reality check in the constant unstable periods of time. Therefore, Hamlet shows post-modern physical expression and outspoken dramaturgy using the effects of mass media in New Realism without breaking up realistic narration. With being the aberration of the Castle Helsingor, the main character Hamlet, expresses lunacy and can be considered as metaphor for young adults whom are broken down and isolated from the economic system. He is a substitute for those who experience agony, anger, torment, etc. and other suppressed emotions in everyday life. With the method of direction in the portrayal of Hamlet show signs of succession in the abundant popularization of the classics by communicating with the audience by following the trend of modern mass media and audio-visual perception; emphasizing the point of the philosophical topic 'life and death,' 'life and theatre,' and 'illusion and reality.'

Optimization of medium components and incubation time for the production of Paecilomyces tenuipes mycelia in submerged culture

  • Ha, Si Young;Jung, Ji Young;Lee, Dong Hwan;Yang, Jae-Kyung
    • 한국버섯학회지
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    • 제19권1호
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    • pp.1-8
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    • 2021
  • The choice of the culture medium is an important factor for the mass production of mycelia in submerged cultures. The influence of liquid medium on the mycelial dry weight of Paecilomyces tenuipes was investigated in this study. The regression equation is expressed as Y=-1292.94187+17.78612X1+18.92425X2+2.11464X3-0.019375X1X2-0.006276X1X3+0.008177X2X3-0.070169X12-0.292175X22-0.008818X32, where Y represents the value of the mycelial dry weight (g/L), X1 is the particle size of wood sawdust in liquid medium (mesh), X2 is the concentration of the wood sawdust in liquid medium, and X3 is incubation time (h). The medium was optimized using a response surface methodology, and the optimal medium contained 30 g of wood sawdust (140 mesh), 20 g of glucose, and 10 g/L of peptone. Under these conditions, the mycelial dry weight reached 38.1 g/L (actual value). The culture medium containing wood sawdust is simple and easy to use, highly efficient, and eco-friendly, and its effectiveness in large preparations of P. tenuipes mycelia with low material costs has been demonstrated.

수명예측 방법에 따른 마이크로스위치의 수명분석 및 신뢰도 예측 (Life Analysis and Reliability Prediction of Micro Switches based on Life Prediction Method)

  • 지정건;신건영;이덕규;손영진;이희성
    • 한국철도학회:학술대회논문집
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    • 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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    • pp.14-21
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    • 2011
  • Reliability means that a product maintains its initial quality and performance at certain period of time(time, distance, cycle etc) under given condition without failure. Given conditions include both environmental condition and operating condition. Environmental condition means common natural environment such as temperature, humidity, vibration, and working condition means artificial environment such as voltage, current load, install place, hours of use, which occurs during using the product. In the field of railway vehicles, although components of railway vehicles with reliability are the trend of mandatory as persisting period of railway vehicles is extended, using components of railway vehicles is insufficient for the practical reliability assessment. but the meaning of the first railway operating agnecy to acquire the parts in the field, the data suggest the reliability of products if you can and can show the reliability of modular units and modular units can provide the reliability of if you can present reliability of the entire system is thought to be here. In this study, lifespan of micro-switch for master controller is analyzed and prediction is performed based on its field data considering the special circumstances of railway vehicles operating agency, such as a large number of trains operates on the same line.

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삼해주 양조에 관한 문헌적 고찰 (A Bibliographical Study on the Processing Methods of Samhaeju)

  • 이성우;배상면
    • 동아시아식생활학회지
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    • 제1권2호
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    • pp.115-127
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    • 1991
  • Information on brew time for Samhaeju can get from the 26 kinds of classical literature, which deal with Samhaeju. Usually, Samhaeju is brewed on any day of the Boar in January of the lunar calendar. However, any day of the Boar in a year seams to be possible for the brew time. In the first step of the manufacture procedure, nonglutinous and glutinous rice are used with the same propontion. The nonglutious and glutinous rice ratio become higher on the 2nd and the 3rd step than in the 1st step. The amount of water adding to the Samhaeju-base is increased step by step. In the first step, processing type of the cereal is predominantly gruel type, which is followed by rice calce. In the 2nd step, rice cake and doughnut-type rice cake are more common type than gruel type. In the 3rd step, processing type of the cereal in Samhaeju is mostly steamed water-soaked rice. Companing China and Japan with Korea, there is difference in the processing types of the cereal. They use steamed water-soaked rice in any step. Nuruk(fermenter) is added to the cold processed cereal in the first step.

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한국과 중국 아동의 방과 후 생활실태와 여가요구 및 학업스트레스 (The After-School Lives of Korean and Chinese Children, Their Need for Leisure, and Academic Stress)

  • 장위천;이완정
    • 가정과삶의질연구
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    • 제27권6호
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    • pp.31-42
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    • 2009
  • The purpose of this study was to compare the after-school lives of Korean and Chinese children, as well as their need on leisure, and academic stress. A total of 746 subjects participated in the study: 369 4th graders and 377 3rd graders; some were sampled in Incheon City, South Korea, and others in Dandong City, China. The SPSS WIN 12.0 Program was used to analyze the collected data, and the statistical methods employed were Frequency, the Chi-square test, the two-way ANOVA. The main results showed that neither Korean nor Chinese children had various after school.activities, or had enough time for leisure. Whereas the Korean children tended to study or use computers during their after-school time, their Chinese counterparts mainly studied or did homework, and they experienced a higher level of academic stress from their parents than the Korean children.

An Orthologous Group Clustering Technique based on the Grid Computing

  • Oh, J.S.;Kim, T.K.;Kim, S.S.;Kwon, H.R.;Kim, Y.C.;Yoo, J.S.;Cho, W.S.
    • 한국생물정보학회:학술대회논문집
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    • 한국생물정보시스템생물학회 2005년도 BIOINFO 2005
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    • pp.72-77
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    • 2005
  • Orthologs are genes having the same function across different species that specialize from a single gene in the last common ancestor of these species. Orthologous groups are useful in the genome annotation, studies on gene evolution, and comparative genomics. However, the construction of an orthologous group is difficult to automate and it takes so much time. It is also hard to guarantee the accuracy of the constructed orthologous groups. We propose a system to construct orthologous groups on many genomes automatically and rapidly. We utilize the grid computing to reduce the sequence alignment time, and we use clustering algorithm in the application of database to automate whole processes. We have generated orthologous groups for 20 complete prokaryotes genomes just in a day because of the grid computing. Furthermore, new genomes can be accommodated easily by the clustering algorithm and grid computing. We compared the generated orthologous groups with COGs (Clusters of orthologous Group of proteins) and KO (KEGG Ortholog). The comparison shows about 85 percent similarity compared with previous well-known orthologous databases.

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수명예측 방법에 따른 마이크로스위치의 수명분석 및 신뢰도 예측 (Life Analysis and Reliability Prediction of Micro-Switches based on Life Prediction Method)

  • 지정건;신건영;이덕규;이희성
    • 시스템엔지니어링학술지
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    • 제7권1호
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    • pp.57-69
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    • 2011
  • Reliability means that a product maintains its initial quality and performance at certain period of time(time, distance, cycle etc) under given condition without failure. Given conditions include both environmental condition and operating condition. Environmental condition means common natural environment such as temperature, humidity, vibration, and working condition means artificial environment such as voltage, current load, install place, hours of use, which occurs during using the product. In the field of railway vehicles, although components of railway vehicles with reliability are the trend of mandatory as persisting period of railway vehicles is extended, using components of railway vehicles is insufficient for the practical reliability assessment. but the meaning of the first railway operating agency to acquire the parts in the field, the data suggest the reliability of products if you can and can show the reliability of modular units and modular units can provide the reliability of if you can present reliability of the entire system is thought to be here In this study, lifespan of micro-switch for master controller is analyzed and prediction is performed based on its field data considering the special circumstances of railway vehicles operating agency, such as a large number of trains operates on the same line.