• 제목/요약/키워드: reference index

검색결과 946건 처리시간 0.025초

Bayesian reliability estimation in a stress-strength system

  • Chang, In-Hong;Oh, Soo-Jin
    • 한국신뢰성학회지:신뢰성응용연구
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    • 제11권2호
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    • pp.151-165
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    • 2011
  • We consider the problem of estimating the system reliability using noninformative priors when both stress and strength follow generalized gamma distributions with index, scale, and shape parameters. We first derive group-ordering reference priors using the reparametrization. We next provide the sufficient condition for propriety of posterior distributions and provide marginal posterior distributions under those noninformative priors. Finally, we provide and compare estimated values of the system reliability based on the simulated values of parameter of interest in some special cases.

다중루프 PID 제어기의 자동 동조 (Automatic Tuning of Multi-Loop PID Controller)

  • 김진훈
    • 대한전기학회논문지
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    • 제39권5호
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    • pp.478-484
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    • 1990
  • An automatic tuning method of a PID controller which is used for single input single output processes is proposed. In the proposed tuning method, the frequency response data model is adopted along with the performance index which is an integral of time weighted square error between reference model and process frequency response data model for tuning. This method is easier to retune when either the process dynamics is changed or the reference model is changed. Finally, an example is provided to show the usefulness of the method.

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정규화된 PWSCC 민감도 지수를 이용한 Alloy 600 기기 검사 우선순위 선정 (Alloy 600 Components Inspection Prioritization Using the Normalized PWSCC Susceptibility Index)

  • 김태룡;김형준
    • 한국압력기기공학회 논문집
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    • 제12권1호
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    • pp.17-22
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    • 2016
  • Alloy 600 widely used in nuclear power plant is susceptible to primary water stress corrosion cracking (PWSCC). It is important to prioritize the inspection of Alloy 600 components using PWSCC susceptibility index. Plant-specific model for the susceptibility index was reviewed. The normalized PWSCC susceptibility index to a reference value is suggested and applied. The result was found to be reasonable.

The Utilization of Google Earth Images as Reference Data for The Multitemporal Land Cover Classification with MODIS Data of North Korea

  • Cha, Su-Young;Park, Chong-Hwa
    • 대한원격탐사학회지
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    • 제23권5호
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    • pp.483-491
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    • 2007
  • One of the major obstacles to classify and validate Land Cover maps is the high cost of acquiring reference data. In case of inaccessible areas such as North Korea, the high resolution satellite imagery may be used for reference data. The objective of this paper is to investigate the possibility of utilizing QuickBird high resolution imagery of North Korea that can be obtained from Google Earth data via internet for reference data of land cover classification. Monthly MODIS NDVI data of nine months from the summer of 2004 were classified into L=54 cluster using ISODATA algorithm, and these L clusters were assigned to 7 classes - coniferous forest, deciduous forest, mixed forest, paddy field, dry field, water, and built-up areas - by careful use of reference data obtained through visual interpretation of the high resolution imagery. The overall accuracy and Kappa index were 85.98% and 0.82, respectively, which represents about 10% point increase of classification accuracy than our previous study based on GCP point data around North Korea. Thus we can conclude that Google Earth may be used to substitute the traditional reference data collection on the site where the accessibility is severely limited.

표준화 방법에 따른 기후변화 취약성 지수의 민감성 연구 (Study on Sensitivity of different Standardization Methods to Climate Change Vulnerability Index)

  • 남기표;김철희
    • 환경영향평가
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    • 제22권6호
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    • pp.677-693
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    • 2013
  • IPCC showed that calculation of climate vulnerability index requires standardization process of various proxy variables for the estimation of climate exposure, sensitivity, and adaptive capacity. In this study, four different methodologies of standardization methods: Z-score, Rescaling, Ranking, and Distance to the reference country, are employed to evaluate climate vulnerability-VRI (Vulnerability-Resilience Indicator) over Korean peninsula, and the error ranges of VRI, arising from employing the different standardization are estimated. All of proxy variables are provided by CCGIS (Climate Change adaptation toolkit based on GIS) which hosts information on both past and current socio-economic data and climate and environmental IPCC SRES (A2, B1, A1B, A1T, A1FI, and A1 scenarios) climate data for the decades of 2000s, 2020s, 2050s, and 2100s. The results showed that Z-score and Rescaling methods showed statistically undistinguishable results with minor differences of spatial distribution, while Ranking and Distance to the reference country methods showed some possibility to lead the different ranking of VRI among South Korean provinces, depending on the local characteristics and reference province. The resultant VRIs calculated from different standardization methods showed Cronbach's alpha of more than 0.84, indicating that all of different methodologies were overall consistent. Similar horizontal distributions were shown with the same trends: VRI increases as province is close to the coastal region and/or it close toward lower latitude, and decreases as it is close to urbanization area. Other characteristics of the four different standardization are discussed in this study.

한국 남해안 대형선망어업의 생태계 위험도 분석에 의한 자원평가 연구 (Stock assessment by ecosystem risk analysis of large purse seine fishery in the southern sea of Korea)

  • 서영일;장창익;이재봉;차형기
    • 수산해양기술연구
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    • 제47권4호
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    • pp.369-389
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    • 2011
  • Changes in ecosystem risks were evaluated using the ecosystem-based fisheries assessment (EBFA) approach of Zhang et al. (2009, 2010) and the comprehensive ecosystem-based fisheries management (EBFM) plan was made for the southern sea of Korea in this study. The risk assessment of the southern sea ecosystem was conducted by establishing ecosystem management objectives and by estimating risk scores (RS) for indicators. To conduct this analysis a number of indicators and their reference points for assessing these risk scores were developed in this study. The number of indicators in the risk analysis was 28 for the quantitative tier 1 analysis and 30 for the qualitative tier 2 analysis. The objective risk index (ORI), species risk index (SRI) and fisheries risk index (FRI) were calculated from the risk scores. Comparing the past (1988) and the current (2008) status of fisheries resources, management implications were discussed. The fishery risk index (FRI) of large purse seine fishery in the southern sea of Korea decreased substantially from 0.972 in 1988 to 0.883 in 2008, and improvement in the management of fisheries operated in the southern sea of Korea.

생태마을의 계획요소 적용 현황 분석에 관한 연구 - 안솔기마을을 중심으로 - (A Study on the Present Condition analysis of Planning Index in Ecovillage - Focusing on Ansolgi village -)

  • 나하영;천득염
    • 한국주거학회논문집
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    • 제18권6호
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    • pp.15-23
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    • 2007
  • It was undeniable that rapid development of scientific technology gave us not only convenience and efficiency but troubles for existence of human due to destruction of ecosystem. Especially, rapid and massive expansion of the city deteriorated those phenomenons. Constructing Ecovillage was important and could be an alternative dwelling model in that it was sustainable so that we could cope with the troubles. But now, meaning and purpose of it was being hazy while thoughtless Ecovillage and notions of it were diffused. This study began to derive planning and evaluation index of Ecovillage on the basis of reference studies and suggestion for the notion and purpose of Ecovillage. This study began to suggest more clear notion of Ecovillage with reference study and derive planning and evaluation index of Ecovillage on the basis of the prior study. After Interviewing research and Field study, the derived index was applied to Ansolgi village and an evaluation for the application was made to suggest a direction and ways to develop and activate Ecovillage. The result of evaluation with the indices showed that Ansolgi village had those declined to visible and easy to make planning factors. Therefore, to activate and sustain Ecovillage in KOREA, even, simultaneous and well linked planning and evaluation indices should be developed. At this moment, since ten years have passed from the beginning of Ecovillage in KOREA, a study reflecting dwellers' evaluation is needed. And it is the most important the dwellers' cognition for the problems and will to resolve them and continuous interest and investment of government and others who are interested in sustainable development.

지문의 중심점 검출에 대한 연구 (A Study on Fingerprint Core-point Detection)

  • 김선주;이동재;김주섭;김재희
    • 대한전자공학회:학술대회논문집
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    • 대한전자공학회 2000년도 하계종합학술대회 논문집(4)
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    • pp.238-241
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    • 2000
  • A fingerprint core-point detection algorithm is presented in this paper. Core-point is useful for fingerprint classification and also for the fingerprint verification since it giver a reference to a fingerprint. Traditional methods of finding the core-point is introduced. These methods are the method using poincare index and the method using sine component of ridge directions. The proposed method is modified algorithm of the latter using the poincare index. The experimental results show that the proposed algorithm achieves almost the same accuracy with faster speed.

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최적제어 설계에 있어서의 2차형 하중행렬의 한 결정법 (AN ALGORITHM FOR DETERMINING THE WEIGHTING MATRICES OF THE QUADRATIC PERFORMANCE INDEX IN OPTIMAL CONTROL)

  • 황창선;김정택
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 1989년도 추계학술대회 논문집 학회본부
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    • pp.407-410
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    • 1989
  • Optimizing transient response for both tracking reference signals and disturbance rejection is determined by the poles and zeros of the transfer function. Thus, optimal pole assignment and how should weighting matrix for the performance index be chosen is very important to achieve optimum transient response. This paper focus its attention on the choosing and analysis of weighting matrix for optimum pole assignment. Optimum pole assignment is defined for linear time-invariant continuous systems.

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