• 한국생산제조학회지
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• 제23권2호
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• pp.118-126
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• 2014

In this paper, a new method is proposed for the five-degree-of-freedom precision alignment and stitching of three-dimensional surface-profile data sets. The control parameters for correcting thealignment error are calculated from the surface profile data for overlapped areas among the adjacent measuring areas by using the "least squares method" and "maximum lag position of cross correlation function." To ensure the alignment and stitching reliability, the relationships betweenthe alignment uncertainty, overlapped area, and signal-to-noise level of the measured profile data are investigated. Based on the results of this uncertainty analysis, an appropriate size is proposed for the overlapped area according to the specimen's surface texture and noise level.

• 대한간호학회지
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• 제45권2호
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• pp.271-279
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• 2015

Purpose: This study was done to examine the relation of uncertainty, uncertainty appraisal, and self-management in patients undergoing hemodialysis, and to identify factors influencing self-management. Methods: A convenience sample of 92 patients receiving hemodialysis was selected. Data were collected using a structured questionnaire and medical records. The collected data were analyzed using descriptive statistics, t-test, ANOVA, Pearson correlations and multiple regression analysis with the SPSS/WIN 20.0 program. Results: The participants showed a moderate level of uncertainty with the highest score being for ambiguity among the four uncertainty subdomains. Scores for uncertainty danger or opportunity appraisals were under the mid points. The participants were found to perform a high level of self-management such as diet control, management of arteriovenous fistula, exercise, medication, physical management, measurements of body weight and blood pressure, and social activity. The self-management of participants undergoing hemodialysis showed a significant relationship with uncertainty and uncertainty appraisal. The significant factors influencing self-management were uncertainty, uncertainty opportunity appraisal, hemodialysis duration, and having a spouse. These variables explained 32.8% of the variance in self-management. Conclusion: The results suggest that intervention programs to reduce the level of uncertainty and to increase the level of uncertainty opportunity appraisal among patients would improve the self-management of hemodialysis patients.

• 한국수자원학회논문집
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• 제42권10호
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• pp.773-783
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• 2009

강우유출모형의 입력 자료로 사용되는 강우 관측 자료의 불확실성이 유량예측에 미치는 영향을 분석하기 위하여 모형변수 검정의 불확실성 연구에서 사용하는 GLUE (Generalized Likelihood Uncertainty Estimation)방법을 입력 자료 부분으로 확장하여 적용 하였다. 독일의 Weida 유역의 강우 관측 자료를 바탕으로 구조적 및 비구조적인 불확실성 부분을 각각 구조적인 오차 수정 과정과 DUE (Data Uncertainty Engine)을 통하여 강우자료를 구성하였다. 이를 유역의 수문학적 작용을 고려하기 위해 선정한 집중형 강우유출모형, PDM (Probability Distribution Model)에 MC (Monte Carlo)와 GLUE 방법을 활용하여 적용하였다. MC검정변수들의 검정 후 반응 표면(Posterior response surface)을 검토하고 GLUE 의 반응검정 모형변수(Behavioural model parameter set)를 선택, 간략한 GLUE 유량곡선들을 계산하였다. 계산된 GLUE 유량곡선들을 모두 합하여 앙상블 유량을 산정하고, 이 유량의 90 분위를 강우량자료 및 모형변수 검정의 불확실성을 고려한 신뢰구간으로 제시하였다. PDM 모형의 결과는 유량곡선의 전구간에서 안정적인 모의 능력을 보여주고 있으나, 첨두유량 부분이 적게 산정되는 문제점을 보이고 있다. 본 연구에서 상대적으로 적은 수의 강우 시나리오 및 반응검정 모형변수의 적용이라는 한계에도 불구하고, GLUE 방법을 강우관측자료의 불확실성 부분으로 확장하여 강우자료 및 변수 검정의 불확실성을 고려한 모의된 유량예측의 신뢰구간의 적용가능성을 보여주고 있다.

• 근관절건강학회지
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• 제4권2호
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• pp.238-248
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• 1997

This study was conducted to identify the characteristics of uncertainty in patients having rheumatoid arthritis. Subjects of the study constituted 528 patients who visited outpatient clinics of two university hospitals and one general hospital in Seoul. A self report questionnaire was used to measure the uncertainty. Reliability coefficients of this instrument was found Cronbach's ${\alpha}=.84$. In data analysis, SPSS PC 6.0 computer program was utilized for descriptive statistics and factor analysis. Three factors were appointed on the basis of literature review for the principal component factor analysis method and Varimax Orthogonal Rotation. The results of factor analysis were as follows ; 1) Three factors for uncertainty were identified through the principal component analysis and varimax rotation, and these contributed 37.4% of the valiance in the total score. Twenty six items among the whole items in the scale loaded above .39 on one of 3 factors. 2) The naming of each factor was as follows : Factor 1 was 'ambiguity' and has 12 items, factor 2 was 'lack of information' and has 8 items, factor 3 was 'unpredictability' and has 7 items. 3) Cronbach's alpha for internal consistency was .84 for the total items and .81, .80, .50 for each of three subscales in that order.

• Earthquakes and Structures
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• 제17권2호
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• pp.131-141
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• 2019

Structural control systems have uncertainties in their structural parameters and control devices which by using reliability analysis, uncertainty can be modeled. In this paper, reliability of controlled structures equipped with semi-active Magneto-Rheological (MR) dampers is investigated. For this purpose, at first, the effect of the structural parameters and damper parameters on the reliability of the seismic responses are evaluated. Then, the reliability of MR damper force is considered for expected levels of performance. For sensitivity analysis of the parameters exist in Bouc- Wen model for predicting the damper force, the importance vector is utilized. The improved first-order reliability method (FORM), is used to reliability analysis. As a case study, an 11-story shear building equipped with 3 MR dampers is selected and numerically obtained experimental data of a 1000 kN MR damper is assumed to study the reliability of the MR damper performance for expected levels. The results show that the standard deviation of random variables affects structural reliability as an uncertainty factor. Thus, the effect of uncertainty existed in the structural model parameters on the reliability of the structure is more than the uncertainty in the damper parameters. Also, the reliability analysis of the MR damper performance show that to achieve the highest levels of nominal capacity of the damper, the probability of failure is greatly increased. Furthermore, by using sensitivity analysis, the Bouc-Wen model parameters which have great importance in predicting damper force can be identified.

• International Journal of Fluid Machinery and Systems
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• 제2권4호
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• pp.278-285
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• 2009

Operational modal analysis (OMA) allows modal parameters, such as natural frequencies and damping, to be estimated solely from data collected during operation. However, a main shortcoming of these methods resides in the evaluation of the accuracy of the results. This paper will explore the uncertainty and possible variations in the estimates of modal parameters for different operating conditions. Two algorithms based on the Least Square Complex Exponential (LSCE) method will be used to estimate the modal parameters. The uncertainties will be calculated using a Monte-Carlo approach with the hypothesis of constant modal parameters at a given operating condition. In collaboration with Andritz-Hydro Ltd, data collected on two different stay vanes from an Andritz-Hydro Ltd Francis turbine will be used. This paper will present an overview of the procedure and the results obtained.

• 한국음향학회지
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• 제43권3호
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• pp.285-292
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• 2024

소나 탐지확률을 계산하는 경우, 수중음향 불확정성은 표준편차가 8 dB ~ 9 dB인 정규분포를 따르는 것으로 고려되고 있다. 하지만, 소나 탐지성능은 실험해역, 해양환경 변동성에 따라 크게 변화하기 때문에 해상실험 데이터 기반의 수중음향 불확정성을 반영한 탐지성능 예측이 필요하다. 본 논문에서는 동해 천해환경에서 측정된 중주파수(2.3 kHz, 3 kHz) 소음준위와 전달손실 자료 기반의 수중음향 불확정성이 산출되었다. 해상실험 데이터 기반의 수중음향 불확정성을 반영한 예상탐지확률을 산출한 후, 이를 기존의 탐지확률 결과, 레일리 분포의 불확정성과 음으로 치우친 분포의 불확정성을 반영한 예상탐지확률 결과와 비교하였다. 결과적으로 각각의 수중음향 불확정성에 따라 탐지영역의 차이가 발생하는 것을 확인할 수 있었다.

• 한국항만경제학회지
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• 제32권1호
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• pp.165-178
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• 2016

컨테이너 항만은 공급망관리(SCM)에 있어서 연결점(link) 역할을 하고 있어 국제 간 무역에서 중요한 위치를 차지하고 있다. 그러므로 컨테이너 항만의 운영 상태를 파악하기 위하여 컨테이너 항만의 운영 효율성을 평가하는 것은 공급망 관리에 있어서 중요한 일이다. 과거 항만의 효율성을 측정하기 위해 많은 방법을 사용되었다. 그 가운데 자료포락분석(DEA, Data Envelopment Analysis) 방법은 가장 일반적인 방법으로 활용되고 있다. 그러나 DEA 모델에 사용되는 투입, 산출 데이터는 때때로 복잡하고 불확실하기 때문에 기존 DEA모델 사용에 한계점이 존재한다. 이 논문에서는 기존모델의 한계를 해결하기 위해 불확실변수를 취급할 수 있는 불확실성 DEA(UDEA, Uncertainty DEA)모델을 제안하였다. 제안된 불확실성 DEA모델을 이용하여 41개 컨테이너 항만의 효율성을 측정하여 불확실성 DEA 모델의 유효성을 검증하였다. 또한 항만 클러스터링 방법으로 항만의 규모별로 효율성을 측정하여 6개의 컨테이너 항만이 효율성이 있음을 식별하였다. 이와 같이 제안된 불확실성 DEA(UDEA)모델이 기존 DEA모델 보다 효율성 측정에 효과적임을 확인하였다.

• 한국관개배수논문집
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• 제11권2호
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• pp.47-54
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• 2004

The flow measurements have been .carried out without the evaluation for data accuracy. For the reliable data acquisition, the experimental watershed has been operated and the uncertainty analysis for flow measurements and the developed rating curves are i

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2006년도 하계학술발표대회 논문집
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• pp.369-374
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• 2006

Quantification of infiltration rate is an important issue in HVAC system design. The infiltration in buildings depends on many uncertain parameters that vary with significant magnitude and hence, the results from standard deterministic simulation approach can be unreliable. The authors utilize uncertainty analysis In predicting the airflow rates. The paper presents relevant uncertain parameters such as meteorological data, building parameters (leakage areas of windows, doors, etc.), etc. Uncertainties of the aforementioned parameters are quantified based on available data from literature. Then, the Latin Hypercube Sampling (LHS) method was used for the uncertainty propagation. The LHS is one of the Monte Carlo simulation techniques that is suited for our needs. The CONTAMW was chosen to simulate infiltration phenomena in a residential apartment that is typical of residential buildings in Korea. It will be shown that the uncertainty propagating through this process is not negligible and may significantly influence the prediction of the airflow rates.