• Journal of the Korean GEO-environmental Society
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• v.13 no.4
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• pp.93-104
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• 2012

Efforts to understand and develop reasonable analysis methods for the uncertainty of ground have been made since the 20th century, and the concept of safety factor has been used. However, this concept has limitation in measuring the relative reliability of ground structures because the representative values of the actually used factors have uncertainty. Nevertheless, there is no method to completely remove uncertainty. In most cases, the ground investigation results in Korea are not enough for applying such statistical methods. Furthermore, performing a design without accurate investigation of consolidation state even though consolidation characteristics such as settlement and consolidation velocity vary greatly by the consolidation history can lead to many problems. Therefore, in this paper, as part of the effort to reduce the uncertainty of design around over consolidation ratio among the consolidation factors, the consolidation state was assessed on the basis of the results of high-quality laboratory tests that were performed in Gwangyang and Busan in the southern coast of Korea. Furthermore, consolidation characteristics such as over consolidation ratio by depth were proposed for different regions through statistical processes such as the test of normality and the removal of abnormal values to reduce the uncertainty of design parameters.

• Journal of Advanced Navigation Technology
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• v.22 no.6
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• pp.630-635
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• 2018

In this paper, we consider the stability condition for the linear discrete systems with time-varying delay and unstructured uncertainty. The considered system has time invariant system matrices for non-delayed and delayed state variables, but its delay time is time-varying within certain interval and it is subjected to nonlinear unstructured uncertainty which only gives information on uncertainty magnitude. In the many previous literatures, the time-varying delay and unstructured uncertainty can not be dealt in simultaneously but separately. In the paper, new stability conditions are derived for the case to which two factors are subjected together and compared with the existing results considering only one factor. The new stability conditions improving many previous results are proposed as very effective inequality equations without complex numerical algorithms such as LMI(Linear Matrix Inequality) or Lyapunov equation. By numerical examples, it is shown that the proposed conditions are able to include the many existing results and have better performances in the aspects of expandability and effectiveness.

• Journal of Korean Clinical Nursing Research
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• v.26 no.3
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• pp.314-326
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• 2020

Purpose: This study was conducted to examine the effects of uncertainty, social support, and sick role behavior on health-related quality of life in patients with peripheral arterial disease. Methods: This study is a descriptive research using self-reporting questionnaire. Data were collected from 167 patients with peripheral arterial disease. Measurement tools were Multidimensional Scale of Perceived Social Support(MSPSS), Mishel's Uncertainty in Illness Scale (MUIS), Sick role behavior measurement tools and SF-36 Version I. The data were analyzed using descriptive statistics, correlation, and regression analysis by using SPSS/WIN 24.0. Results: Factors that significantly influenced physical health-related quality of life were age (β=-.19, p=.010), monthly income (β=.17, p=.027), uncertainty (β=-.29, p<.001), and exercise and rest (β=.28, p<.001) that all together accounted for 32.6% of the variance. Factors that significantly influenced mental health-related quality of life were monthly income (β=.20, p=.015), drinking (β=.17, p=.040), uncertainty (β=-.24, p=.001), and exercise and rest in sick role behavior (β=.26, p=.003) that all together accounted for 18.2% of the variance. Social support was an insignificant factor on physical and mental health-related quality of life. Conclusion: To improve the health-related quality of life of people with peripheral arterial disease, it is necessary to develop a systematic nursing intervention program including a strong support system, education, strategies for alcohol abstinence, and exercise and rest therapy.

• Journal of radiological science and technology
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• v.46 no.3
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• pp.219-229
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• 2023

In this study, basic characteristics such as reproducibility, linearity, and directionality of RPL glass dosimeters were evaluated to improve the reliability of dose evaluation through RPL glass dosimeters, and uncertainty elements such as sensitivity by glass element and magazine slot sensitivity were evaluated. Using a mathematical model to calibrate the measured values of the RPL glass dosimeter, the measurement uncertainty was calculated assuming an example. As a result of the characteristic evaluation, the RPL glass dosimeter showed excellent performance with a standard deviation of ±1% (1 SD) for the reproducibility of the reading process, a coefficient of determination for linearity of 0.99997. And the read-out of the RPL glass dosimeter are affected by the circular rotation direction of the glass dosimeter during irradiation, fading according to the period after irradiation, the number of laser pulses of the reader, and response degradation due to repeated reading, it is judged that measurement uncertainty can be reduced by irradiation and reading in consideration of these factors. In addition, it was confirmed that the dose should be determined by calculating the correction factors for the sensitivity of each element and, the sensitivity of each reading magazine slot. It is believed that the reliability of dosimetry using glass dosimeters can be improved by using a mathematical model for correction of glass dosimeter readings and calculating measurement uncertainty.

• Analytical Science and Technology
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• v.26 no.2
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• pp.125-134
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• 2013

This study was demonstrated to estimate the measurement uncertainty of 23 multiple-component amino acids from beef bone extract by high performance liquid chromatography (HPLC). The sources of measurement uncertainty (i.e. sample weight, final volume, standard weight, purity, standard solution, calibration curve, recovery and repeatability) in associated with the analysis of amino acids were evaluated. The estimation of uncertainty obtained on the GUM (Guide to the expression of uncertainty in measurement) and EURACHEM document with mathematical calculation and statistical analysis. The content of total amino acids from beef bone extract was 36.18 g/100 g and the expanded uncertainty by multiplying coverage factor (k, 2.05~2.36) was 3.81 g/100 g at a 95% confidence level. The major contributors to the measurement uncertainty were identified in the order of recovery and repeatability (25.2%), sample pretreatment (24.5%), calibration-curve (24.0%) and weight of the reference material (10.4%). Therefore, more careful experiments are required in these steps to reduce uncertainties of amino acids analysis with a better personal proficiency improvement.

• Analytical Science and Technology
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• v.24 no.1
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• pp.1-9
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• 2011

We described an estimation of measurement uncertainty in quantitative analysis of 11-nor-9-carboxy-${\Delta}^9$-tetrahydrocannabinol (THC-COOH), the metabolite of ${\Delta}^9$-tetrahydrocannabinol, in hair samples by using the bead-assisted liquid-liquid extraction and gas chromatography-tandem mass spectrometric (GC-NCI-MS/MS) detection. Traceability of measurement was established through the use of reference materials, calibrated volumetric tubes, volume measuring devices, and measuring instruments. The analytical results were compared and the different contributions to the uncertainty were evaluated. Inter-day variation was performed by using statistical analysis of several indicative factors. Measurement uncertainty associated with the analyte in real forensic hair samples were estimated using QC data. The major factor of contribution to combined standard uncertainty was inter-day repeatability, while those associated with preparation of analytical standard and also sample of weight were insignificant considering the degree of contribution. Relative uncertainty of relative extended standard uncertainty divided into the measured concentration of the analyte was 17% in a hair sample. The uncertainty of result evaluation will be invaluable to improve quality of the analysis.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.4
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• pp.248-259
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• 2017

This descriptive correlational study was conducted to identify the factors influencing the uncertainty of patients undergoing chemotherapy for lung neoplasms. One hundred and eleven patients were recruited from the chemotherapy clinic of a university hospital. Data were collected from July 25 to December 31, 2014, and analyzed by descriptive statistics, the t-test, ANOVA, the Scheffe test, Pearson's product moment correlation coefficients and multiple regression analysis with SPSS for Windows Version 18.0. The mean score of the uncertainty of the patients undergoing chemotherapy for lung neoplasms was 2.61(${\pm}0.46$), which was higher than that of the patients with other diseases. The uncertainty was positively correlated with the seriousness of the illness (r=.74, p<.01) and consistency of the symptoms (r=.27, p<.01). Multiple regression analysis showed that the (main) factor influencing the uncertainty was the seriousness of the illness, which explained 54% of the uncertainty of the patients undergoing chemotherapy for lung neoplasms. As a result, nursing interventions are needed to reduce the uncertainty of lung neoplasm patients who are receiving chemotherapy. The seriousness of the illness should be considered when developing nursing interventions to reduce the uncertainty of lung neoplasm patients.

• Journal of Korea Water Resources Association
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• v.56 no.8
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• pp.509-520
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• 2023

Various drought indices are widely used for assessing drought conditions which are affected by many factors such as precipitation, soil moisture, and runoff. The values of drought indices varies depending on hydro-meteorological data and calculation formulas, and the judgment of the drought condition may also vary. This study selected four calculation components such as precipitation data length, accumulation period, probability distribution function, and parameter estimation method as the sources of uncertainty in the calculation of standardized precipitation index (SPI), and evaluated their contributions to the uncertainty using root mean square error (RMSE) and linear mixed model (LMM). The RMSE estimated the overall errors in the SPI calculation, and the LMM was used to quantify the uncertainty contribution of each factor. The results showed that as the accumulation period increased and the data period extended, the RMSEs decreased. The comparison of relative uncertainty using LMM indicated that the sample size had the greatest impact on the SPI calculation. In addition, as sample size increased, the relative uncertainty related to the sample size used for SPI calculation decreased and the relative uncertainty associated with accumulation period and parameter estimation increased. In conclusion, to reduce the uncertainty in the SPI calculation, it is essential to collect long-term data first, followed by the appropriate selection of probability distribution models and parameter estimation methods that represent well the data characteristics.

• Journal of the Korean Geotechnical Society
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• v.21 no.3
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• pp.5-17
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• 2005

Spatial uncertainty of Busan marine clay ground, which commonly occurs during site investigation testing, data analysis and transformation modeling, has been described. In this paper geotechnical uncertainty of shear strength indicator $N_k$ has been quantified in both horizontal direction and vertical direction using geostatistical Kriging method. Most of soil data used are from 25 boring tests, 75 laboratory tests, 124 field vane tests and 25 cone penetration tests (CPT). CPT-$N_k$ data for undrained shear strength determination, which are the most important properties in geotechnical design stages, have been analysed. Comparison between cone factor from conventional CPT-based method and that of geostatistical method shows that geostatistical Kriging method is an ideal tool to quantify the spatial variability of uncertainty from self-correlation of soil property of interest, and can be recommended to identify the spatial distribution of consolidation .md shear strength of soils at any sites concerned.

• Nuclear Engineering and Technology
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• v.54 no.2
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• pp.523-531
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• 2022

In order to study the sensitivity and the uncertainty of the Moroccan research reactor TRIGA Mark II, a model of this reactor has been developed in our ERSN laboratory for use with the N-Particle MCNP Monte Carlo transport codes (version 6). In this article, the sensitivities of the effective multiplication factor of this reactor are evaluated using the ENDF/B-VII.0, ENDF/B-VII.1 and JENDL-4.0 libraries and in 44 energy groups, for the cross sections of the fuel (U-235 and U-238) and the moderator (H-1 and O-16). However, the quantification of the uncertainty of the nuclear data is performed using the nuclear code NJOY99 for the generation and processing of covariance matrices. On the one hand, the highest uncertainty deviations, calculated using the ENDFB-VII.1 and JENDL4.0 evaluations, are 2275, 386 and 330 pcm respectively for the reactions U₂₃₅(n, f), $ U_{235}(n\bar{\nu})$ and H₁(n, γ). On the other hand, these differences are very small for the neutron reactions of O-16 and U-238. Regarding the neutron spectra, in CT-mid plane, they are very close for the three evaluations (ENDF/B-VII.0, ENDF/B-VII.1 and JENDL-4.0). These spectra present two peaks (thermal and fission) around the energies 0.05 eV and 1 MeV.