• Title/Summary/Keyword: physical uncertainty

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IMPLEMENTATION OF DATA ASSIMILATION METHODOLOGY FOR PHYSICAL MODEL UNCERTAINTY EVALUATION USING POST-CHF EXPERIMENTAL DATA

  • Heo, Jaeseok;Lee, Seung-Wook;Kim, Kyung Doo
    • Nuclear Engineering and Technology
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    • v.46 no.5
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    • pp.619-632
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    • 2014
  • The Best Estimate Plus Uncertainty (BEPU) method has been widely used to evaluate the uncertainty of a best-estimate thermal hydraulic system code against a figure of merit. This uncertainty is typically evaluated based on the physical model's uncertainties determined by expert judgment. This paper introduces the application of data assimilation methodology to determine the uncertainty bands of the physical models, e.g., the mean value and standard deviation of the parameters, based upon the statistical approach rather than expert judgment. Data assimilation suggests a mathematical methodology for the best estimate bias and the uncertainties of the physical models which optimize the system response following the calibration of model parameters and responses. The mathematical approaches include deterministic and probabilistic methods of data assimilation to solve both linear and nonlinear problems with the a posteriori distribution of parameters derived based on Bayes' theorem. The inverse problem was solved analytically to obtain the mean value and standard deviation of the parameters assuming Gaussian distributions for the parameters and responses, and a sampling method was utilized to illustrate the non-Gaussian a posteriori distributions of parameters. SPACE is used to demonstrate the data assimilation method by determining the bias and the uncertainty bands of the physical models employing Bennett's heated tube test data and Becker's post critical heat flux experimental data. Based on the results of the data assimilation process, the major sources of the modeling uncertainties were identified for further model development.

Surface Color Measurement Uncertainties

  • Hwang, Jisoo;Jeong, Ki-Lyong
    • Journal of the Optical Society of Korea
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    • v.19 no.6
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    • pp.649-657
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    • 2015
  • We present a surface color measurement including quantities of surface color, methods, and uncertainty evaluation. Based on a relation between spectral reflectance and surface color, we study how an uncertainty of spectral reflectance propagates to surface color. In analyzing the uncertainty propagation, we divide the uncertainty into uncorrelated components, fully correlated components, and correlated components with spectrally varying correlations. As an experimental example, we perform spectro-reflectometric measurements for ceramic color plates. With measured spectral reflectance and its uncertainty evaluation, we determine surface color and analyze uncertainties of the ceramic color plates.

Effects of Uncertainty and Depression on the Quality of Life of Elderly People (노인의 불확실성과 우울이 삶의 질에 미치는 영향)

  • Kim, Hyun-Seung;Cho, Sung-Hyoun
    • Journal of The Korean Society of Integrative Medicine
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    • v.10 no.3
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    • pp.209-219
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    • 2022
  • Purpose : The purpose of this study was two-fold: to investigate the effects of uncertainty and depression on the quality of life (QoL) of elderly people with chronic diseases and to provide basic data on the physical, emotional, and psychological factors affecting their QoL in the field of physical therapy. Methods : A questionnaire covering uncertainty, depression, and QoL was distributed among 320 elderly people. Pearson's correlation analysis was performed to examine the correlation between uncertainty (ambiguity, complexity, inconsistency, and unpredictability), depression, and QoL (physical, psychological, social, and living environment domains) of the respondents; furthermore, multiple regression analysis was performed to identify the factors affecting the QoL of the respondents with a chronic disease. Results : The sub-factors of uncertainty and QoL-"complexity and social domain" (r=-.295, p<.001), "complexity and living environment domain" (r=-.302, p<.001), and "inconsistency and living environment domain" (r=-.360, p<.001)-showed a negative (-) correlation, as did depression and the sub-factors of QoL-"depression and physical domain" (r=-.782, p<.001), "depression and psychological domain" (r=-.876, p<.001), "depression and social domain" (r=-.668, p<.001), and "depression and living environment domain" (r=-.731, p<.001). The factors affecting QoL were complexity (𝛽=-.122, p<.001), inconsistency (𝛽=-.102, p=.002), unpredictability (𝛽=.112, p<.001), and depression (𝛽=-.850, p<.001). The relative influence of the independent variables was in the order of depression, complexity, unpredictability, and inconsistency, and the explanatory power was 77.1 % (F=215.853, p<.001). Conclusion : It is important to help the elderly with chronic diseases reduce the negative impact on their quality of life by helping them gain support from their families and medical professionals and by increasing their understanding through communication so that they can transition from negative emotions to positive emotions of opportunity.

Uncertainty assessment of industrial platinum resistance thermometers for different lead-wire connection methods (산업용 백금저항온도센서의 결선방식에 따른 측정불확도 평가방법)

  • Kim, Yong-Gyoo;Gam, Kee-Sool;Yang, In-Seok
    • Journal of Sensor Science and Technology
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    • v.18 no.4
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    • pp.322-326
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    • 2009
  • To estimate the measurement uncertainty for industrial platinum resistance thermometers(IPRTs) made with 3-wire connection, the immersion temperature profile was investigated using a liquid bath. Two types of IPRTs having lead wires made of silver and nickel were constructed and the immersion profiles were measured at temperatures from -50 $^{\circ}C$ to 250 $^{\circ}C$ using 3-wire and 4-wire method. As immersion depth and temperature increased, the resistances measured by 3-wire method increased linearly but not for 4-wire method. To calibrate a 3-wire IPRT, the immersion effect must be accounted for. We propose a linear equation to assess correctly the measurement uncertainty.

Perceived Anxiety and Uncertainty in Hematopoietic Stem Cell Transplantation Recipients to and from Isolation Unit (격리병동 입.퇴실시 조혈모세포 이식 환자가 지각하는 불안과 불확실성)

  • Kim, Hye-Jo;Choi, Dong-Won;Park, Ho-Ran;Sohng, Kyeong-Yae
    • Journal of Korean Academy of Fundamentals of Nursing
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    • v.13 no.3
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    • pp.428-436
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    • 2006
  • Purpose: To investigate the levels of uncertainty and anxiety at admission and discharge to the isolation unit for patients undergoing hematopoietic stem cell transplantation (HSCT). Method: The data were collected from 60 patients who were admitted to the department of HSCT. Uncertainty and anxiety were assessed using the Mishel Uncertainty in Illness Scale (MUIS) and Anxiety Inventory (STAI). Collected data were analyzed using the SAS program. Results: The mean score for anxiety at admission was 2.20, and at discharge 2.10. The mean score for uncertainty at admission was 2.19, and at discharge 2.07. The anxiety at admission the group with physical discomfort was higher than that of group without physical discomfort. A positive relationship was found between anxiety and uncertainty at admission and at discharge. The major variables were expectation for cure and physical discomfort, explaining 25.87% of the anxiety at admission. The major variable was expectation for cure, explaining 20.94% of the uncertainty at admission. Conclusion: Front the above results, it can be concluded that support and consideration are required to reduce anxiety of the inpatient in single room.

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A Linear Reservoir Model with Kslman Filter in River Basin (Kalman Filter 이론에 의한 하천유역의 선형저수지 모델)

  • 이영화
    • Journal of Environmental Science International
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    • v.3 no.4
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    • pp.349-356
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    • 1994
  • The purpose of this study is to develop a linear reservoir model with Kalman filter using Kalman filter theory which removes a physical uncertainty of :ainfall-runoff process. A linear reservoir model, which is the basic model of Kalman filter, is used to calculate runoff from rainfall in river basin. A linear reservoir model with Kalman filter is composed of a state-space model using a system model and a observation model. The state-vector of system model in linear. The average value of the ordinate of IUH for a linear reservoir model with Kalman filter is used as the initial value of state-vector. A .linear reservoir model with Kalman filter shows better results than those by linear reserevoir model, and decreases a physical uncertainty of rainfall-runoff process in river basin.

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Uncertainty, Depression, and Quality of Life in Patients with Stroke (뇌졸중 환자가 지각하는 불확실성, 우울, 삶의 질)

  • Kang, Yu Jin;Yoo, Hye Jin;Kim, Keum Soon
    • Journal of muscle and joint health
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    • v.27 no.2
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    • pp.189-198
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    • 2020
  • Purpose: The prevalence rate of stroke is increasing due to the rise in the aging population. The stroke sequela, including physical and mental disabilities, remain even though patients are alive, and these circumstances are causing major problems, both socially and economically. This correlation study aimed to identify uncertainty, depression, and quality of life among stroke patients. Methods: Participants included 94 outpatients who were diagnosed with stroke and discharged from a tertiary hospital in S city. Between September and October 2014, a survey on uncertainty, depression, and quality of life was conducted. Data collected were analyzed using SPSS 22.0. Results: The average scores of uncertainty, depression, and quality of life were 48.36 out of 80, 41.90 out of 80, and 175.94 out of 245, respectively. The uncertainties exhibited a positive correlation with depression and a negative correlation with quality of life. The correlation between depression and quality of life was found to be negative. Conclusion: To enhance the quality of life of stroke patients, interventions to reduce uncertainty and depression as well as improve physical care to reduce difficulties in daily living should be implemented.

Uncertainty Quantification of the Experimental Spectroscopic Factor from Transfer Reaction Models

  • Song, Young-Ho;Kim, Youngman
    • Journal of the Korean Physical Society
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    • v.73 no.9
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    • pp.1247-1254
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    • 2018
  • We study the uncertainty stemming from different theoretical models in the spectroscopic factors extracted from experiments. We use three theoretical approaches, the distorted wave Born approximation (DWBA), the adiabatic distorted wave approximation (ADWA) and the continuum discretized coupled-channels method (CDCC), and analyze the $^{12}C(d,p)^{13}C$, $^{14}C(d,p)^{15}C$ reactions. We find that the uncertainty associated with the adopted theoretical models is less than 20%. We also investigate the contribution from the remnant term and observe that it gives less than 10% uncertainty. We finally make an attempt to explain the discrepancy in the spectroscopic factors of $^{17}C(\frac{3}{2}^+)$ between the ones extracted from experiments and from shell model calculations by analyzing the $^{16}C(d,p)^{17}C$ reaction.

Uncertainty Evaluation of Color Measurement on Light Sources and Display Devices (광원 및 디스플레이 기기의 색특성 측정의 불확도 평가)

  • Park, Seong-Chong;Lee, Dong-Hoon;Kim, Yong-Wan;Park, Seung-Nam
    • Korean Journal of Optics and Photonics
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    • v.20 no.2
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    • pp.110-117
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    • 2009
  • This work introduces the uncertainty evaluation formulation on color measurement of light sources and display devices, such as CIE 1931 (x, y) chromaticity, CIE 1960 (u, v) chromaticity, correlated color temperature, and distribution temperature. All the mentioned quantities are reduced from spectral data in the visible range, for which uncertainties are strongly correlated between different wavelengths. Using matrix algebra we have formulated the uncertainty propagation from the SI- traceable spectral irradiance standard to the individual color related measurement quantities taking the correlation between wavelengths into account. As a result, we have demonstrated uncertainty evaluation examples of 3 types of light sources: CIE illuminant A, LED white light, and LCD white light. This method can be applied to any other quantities based on spectral measurement such as solar irradiance, material color measurement, etc.

Evaluation of Uncertainty Sources in Temperature Measurement Using Platinum Resistance Thermometer Caused by Temperature Gradient in Furnace and Sealed-type Freezing Point Cells (전기로 및 봉입형 응고점 셀 내의 온도구배가 미치는 표준백금저항온도계 온도측정의 불확도 요소 평가)

  • Kang, Kee-Hoon;Gam, Kee-Sool;Kim, Yong-Gyoo;Song, Chang-Ho
    • Journal of Sensor Science and Technology
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    • v.13 no.6
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    • pp.411-416
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    • 2004
  • In the international temperature scale of 1990 (ITS-90), standard platinum resistance thermometer (SPRT) is a defining standard thermometer used in the temperature range from 13.8033 K to $961^{\circ}C$. Uncertainty of SPRT is about several mK and uncertainty of defining fixed points of the ITS-90 which is used for calibrating SPRT is about several tenth of mK. Above $0^{\circ}C$. the defining fixed points are gallium melting point and indium, tin, zinc, aluminium and silver freezing points which are all realized using an electric furnace or a liquid bath. To realize freezing point of tin ($231.928^{\circ}C$) and zinc ($419.527^{\cir}C$), two 3-zone furnaces which have 3 electric heaters were manufactured. Temperature gradient of the constructed furnaces were tested. Uncertainty caused by temperature gradient of furnace and immersion effect of SPRT in the sealed-type freezing point cells were evaluated 0.038 mK for tin freezing point and 0.036 mK for zinc freezing point.