• 제목/요약/키워드: effective variables

검색결과 3,077건 처리시간 0.029초

고온초전도케이블 단말 저온조의 열유동해석 (Numerical Analysis of Thermal Flow in HTS Cable Termination)

  • 김도형;조승연;양형석;김동락;김승현
    • 한국초전도저온공학회:학술대회논문집
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    • 한국초전도저온공학회 2003년도 학술대회 논문집
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    • pp.163-166
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    • 2003
  • Maintaining low temperature is very important in operating HTS cable termination in which Joule heat is generated at current lead. In this study, numerical analysis using FLUENT is performed to find an optimized flow conditions for effective cooling of HTS cable terminal system using subcooled liquid nitrogen (L$N_2$) as refrigerant. The variables considered here are mass flow rate of L$N_2$, location of inlet and diameter of inlet and outlet. Simplified models are investigated under these variables. Based on maximum temperatures in the cryostat, the configuration for effective cooling of HTS cable was determined.

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Comparison of Database Models for Developing a Pavement Performance Analysis System

  • Choi Jae-ho
    • 한국건설관리학회논문집
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    • 제5권4호
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    • pp.79-86
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    • 2004
  • One of the most difficult tasks in pavement management information systems is establishing the links between performance measures of a structure and the design and construction inputs. In-situ pavement performance can be considered a response variable to many project input variables, such as design, construction, and traffic loading effects. If we are to fully understand the component of pavement performance and specify the inputs through design and construction specifications to achieve that performance we must develop quantitative relationship between input and response variables through a scientific, fully integrated Pavement Performance Analysis System (PPAS). Hence, the objective of this study is to design a database model required for developing an effective database template that will allow analysis of pavement performance measures based on design and construction information linked by location. In order to select the most appropriate database model, a conceptual database model (Entity Relationship Model) and dimensional model, which is believed to be the most effective modeling technique for data warehouse project, are designed and compared. It is believed that other state highway agencies could adopt the proposed design strategy for implementing a PPAS at the discretion of the state highway agencies.

국방조달에서 부정당업자 판별분석 모형 개발 (Discriminant Analysis for the Prediction of Unlawful Company in Defense Procurement)

  • 한홍규;최석철
    • 한국군사과학기술학회지
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    • 제14권3호
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    • pp.467-473
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    • 2011
  • The contractor management for the effective defense project is essential factor in the modern defense acquisition task. The occurrence of unlawful company causes hastiness for project manager and setback to the deployment of defense weapon system. In this paper, we develop a prediction model for the effective defense project by using the discriminant analysis and analyse the variables that discriminate the unlawful company in many variables. It is expected that our model can be used to improve the project management capability of defense acquisition and contribute to the establishment of efficient procurement procedure through entry of the reliable defense manufacturer.

Employing Response Surface Methodology for optimization of slow release Biostimulant ball in contaminated coastal sediments in Busan, South Korea

  • Song, Young-Chae;Subha, Bakthacachallam;Woo, Jung Hui
    • 한국항해항만학회:학술대회논문집
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    • 한국항해항만학회 2014년도 추계학술대회
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    • pp.87-88
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    • 2014
  • The Coastal sediment is highly contaminated due to ship transportation, industries discharges and urban sources. Various contaminants release into seawater and settle in marine sediment and it significantly affect marine eco system. In the present study evaluated the optimization of slow release biostimulant ball (BSB) in coastal sediment in busan. The effective variables like BSB size, distance and month variables on VS reduction was determined by using Response surface methodology(RSM). The analysis of variance (ANOVA) and coefficient determination (R2) of VS was 0.9369 and maximum reduction of VS was obtained in 3cm ball size and 5.5cm distance and 4 month interval time. This result revealed that the BSB in effective VS reduction in coastal sediment.

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일체화 성형 서브프레임 개발을 위한 벤딩 공정의 영향성 연구 (A Study of Bending Process for Development of Subframe by Hydroforming)

  • 서창희;이우식;김헌영;임희택
    • 한국소성가공학회:학술대회논문집
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    • 한국소성가공학회 2003년도 춘계학술대회논문집
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    • pp.262-265
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    • 2003
  • In the present study, subframe was developed using hydroforming technology. The manufacturing process for subframe consists of tube bending, pre-forming and hydroforming. The effects of bending process for manufacturing hydroformed subframe were researched. And the variables of bending process were studied by FEM simulation. The bending method is rotary draw bending that is the most popular, cost-effective bending method for thin walled tubes.

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점진적 정수 중단 하에서의 와이블분포에 대한 계량형 샘플링검사 (Variables Sampling Plans for the Weibull Distribution under Progressive Failure Censoring)

  • 이상호;전치혁
    • 한국경영과학회:학술대회논문집
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    • 한국경영과학회/대한산업공학회 2005년도 춘계공동학술대회 발표논문
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    • pp.922-926
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    • 2005
  • Progressively censored variables sampling plans are proposed for the lot acceptance of parts whose life follows Weibull distribution with known shape parameter. Progressive type-II censoring gives us not only time to failure but also degradation information. So, one can construct more flexible and more cost effective sampling plans. Design parameters of our sampling plan are determined by using the usual two-point approach.

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승차감 향상을 위한 액티브서스펜션의 제어알고리즘 (Control Algorithms of Active Suspension Systems for Ride Comfort Improvement)

  • 탁태오
    • 산업기술연구
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    • 제12권
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    • pp.61-67
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    • 1992
  • Two control algorithms of active suspension system for improving ride quality are described and their effectiveness is assessed using a quarter car model. Optimal control approach demonstrates great flexibility to meet various running conditions of a vehicle. However, in order to fully utilize the power of optimal control apporach, accurate estimation of the state variables is essential. Simple, yet effective sky-hook algorithm seems to be well suited for real application because of its much relaxed requirements on sensing the stste variables and relative easiness to implment.

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건식 진공펌프의 상태진단 및 예지보수 기법 (Predictive Diagnosis and Preventive Maintenance Technologies for Dry Vacuum Pumps)

  • 정완섭
    • 진공이야기
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    • 제2권1호
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    • pp.31-34
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    • 2015
  • This article introduces fundamentals of self-diagnosis and predictive (or preventive) maintenance technologies for dry vacuum pumps. The state variables of dry pumps are addressed, such as the pump and motor body temperatures, consumption currents of main and booster pumps, mechanical vibration, and exhaust pressure, etc. The adaptive parametric models of the state variables of the dry pump are exploited to provide dramatic reduction of data size and computation time for self-diagnosis. Two indicators, the Hotelling's $T^2$ and the sum of squares residuals (Q), are illustrated to be quite effective and successful in diagnosing dry pumps used in the semiconductor processes.

기후변화 취약성 지수 산출을 위한 한반도 관측 기후 특성 분석 (Analysis of Climate Characteristics Observed over the Korean Peninsula for the Estimation of Climate Change Vulnerability Index)

  • 남기표;강정언;김철희
    • 환경영향평가
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    • 제20권6호
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    • pp.891-905
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    • 2011
  • Climate vulnerability index is usually defined as a function of the climate exposure, sensitivity, and adaptive capacity, which requires adequate selection of proxy variables of each variable. We selected and used 9 proxy variables related to climate exposure in the literature, and diagnosed the adequacy of them for application in Korean peninsula. The selected proxy variables are: four variables from temperature, three from precipitation, one from wind speed, and one from relative humidity. We collected climate data over both previous year (1981~2010) and future climate scenario (A1B scenario of IPCC SERES) for 2020, 2050, and 2100. We introduced the spatial and temporal diagnostic statistical parameters, and evaluated both spatial and time variabilities in the relative scale. Of 9 proxy variables, effective humidity indicated the most sensitive to climate change temporally with the biggest spatial variability, implying a good proxy variable in diagnostics of climate change vulnerability in Korea. The second most sensitive variable is the frequency of strong wind speed with a decreasing trend, suggesting that it should be used carefully or may not be of broad utility as a proxy variable in Korea. The A1B scenario of future climate in 2020, 2050 and 2100 matches well with the extension of linear trend of observed variables during 1981~2010, indicating that, except for strong wind speed, the selected proxy variables can be effectively used in calculating the vulnerability index for both past and future climate over Korea. Other local variabilities for the past and future climate in association with climate exposure variables are also discussed here.

시스템다이내믹스를 이용한 신규간호사의 조직사회화과정 모델 개발 (The Development of an Organizational Socialization Process Model for New Nurses using a System Dynamics Approach)

  • 최순옥
    • 대한간호학회지
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    • 제35권2호
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    • pp.323-335
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    • 2005
  • Purpose: The purpose of this study was to examine the problems and relevant variables for effective Organizational Socialization of new nurses, to produce a causal map, to build up a simulation model and to test its validity. Method: The basic data was collected from Sep. 2002 to July 2003. The Organizational Socialization process of new nurses was analyzed through a model simulation. The VENSIM 5.0b DSS program was used to develop the study model. Result: This Model shows interrelation of these result variables: organizational commitment, job satisfaction, job performance, intention of leaving the work setting, decision making ability, and general results of Organizational Socialization. The model's factors are characteristic of organization and individual values, task-related knowledge and skills, and emotion and communication that affects new nurses' socialization process. These elements go through processes of anticipatory socialization, encounter, change and acquisition. The Model was devised to induce effective Organizational Socialization results within 24 months of its implementation. The basic model is the most efficient and will also contribute to the development of knowledge in the body of nursing. Conclusion: This study will provide proper direction for new Nurse's Organizational Socialization. Therefore, developing an Organizational Socialization Process Model is meaningful in a sense that it could provide a framework that could create effective Organizational Socialization for new nurses.