• Journal of the Society of Naval Architects of Korea
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• v.51 no.3
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• pp.212-219
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• 2014

As subsea production has been revived up, the demand of subsea equipment has also been increased. Among the equipment, subsea tree plays a major role in safety. The tubing hanger is one of the most important components in subsea tree. In this study structural reliability analysis on dual bore tubing hanger of subsea tree is performed. The target reliability which is introduced in ISO regulation is used for judging whether tubing hanger is safe or not. The considered loads are working pressure, working temperature and suspended tubing weight. Thermal-stress analysis on tubing hanger is performed and kriging model is created based on the results of FEM analysis. According to von Mises criterion, limit state equation can be estimated. Reliability analysis is performed by using level 2 method and the result is verified by that of Monte Carlo Simulation. For finding most probable failure point, enhanced HL-RF method is adopted. Because the reliability of model doesn't reach target reliability, an improvement measure should be considered. Thus, it is suggested to change the material of tubing hanger main body to AISI 4140.

• Physical Therapy Korea
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• v.14 no.2
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• pp.61-67
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• 2007

The purpose of this study was to examine inter- and intra-examiner reliability of the sacroiliac joint (SIJ) anatomical landmarks palpation. Two physical therapists and one doctor specializing in rehabilitation examined 22 asymptomatic subjects. They examined anterior superior iliac supine (ASIS), posterior superior iliac supine (PSIS) and iliac crest (IC). For the assessment of intra-examiner reliability, 3 examiners repeated the measurements 3 times over a 2-week interval. Kappa (Kg) yielded intra-examiner reliability that ranged between slight to fair for the ASIS (Kg=.06 to .26; mean Kg=.19), and slight for the PSIS(Kg=-.04 to .18; mean Kg=.07) and slight to fair for the IC (Kg=.06 to .32; mean Kg=.21). Inter-examiner reliability was slight (ASIS Kg=.13; PSIS Kg=.05; IC Kg=.14). These results suggest that the reliability of the assessing SIJ anatomical landmarks using palpation and observation as an indication of SIJ dysfunction still remains questionable. Before this test can be relied upon as an accurate indicator of SIJ dysfunction, it must undergo further research. This further research needs to examine not only reliability, but also validity, sensitivity and specificity.

• Journal of the Korean GEO-environmental Society
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• v.20 no.12
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• pp.41-47
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• 2019

This paper deals with the reliability analysis of foundation for an offshore wind turbine system. Reliability analyses were carried out for suction bucket foundation considering the uncertainties in soil and structural parameters. In reliability analysis, the vertical and lateral resistances are defined as base limit states. The case studies were carried out using the preliminarily designed foundations at western-south mainland sea of Korea. From reliability analyses, vertical resistance for free-slip condition has overall lower reliability index, and submerged unit weight and internal friction angle of seabed soil are governing factors in vertical and lateral resistance in this case.

• 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.

• Particle and aerosol research
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• v.7 no.3
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• pp.99-108
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• 2011

To establish area specific control strategies for the reduction of the ozone concentration, the Ozone Isopleth Plotting Package for Research(OZIPR) model has been widely used. However, the model results tend to changed by various input parameters such as the background concentration, emission amount of NOx and volatile organic compounds (VOCs), and meteorological condition. Thus, sensitivity analysis should be required to ensure the reliability of the result. The OZIPR modeling results for five local government districts in the Seoul Metropolitan Area (SMA) in June 2000 were used for the sensitivity analysis. The sensitivity analysis result showed that the modeling result of the SMA being VOC-limited region be still valid for a wide range of input parameters' variation. The estimated ozone concentrations were positively related with the initial VOCs concentrations while were negatively related with the initial NOx concentrations. But, the degree of the variations at each local district was different suggesting area specific characteristics being also important. Among the five local governments, Suwon was chosen to identify other variance through the period from April to September in 2000. The monthly modeling results show different ozone values, but still showing the characteristics of VOCs-limited region. Limitations due to not considering long range transport and transfer from neighbor area, limitation of input data, error between observed data and estimated data are all discussed.

• Journal of Industrial Technology
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• v.26 no.B
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• pp.83-92
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• 2006

A probabilistic analysis model. one of reliability analysis methods introducing the concept of variables, was developed to investigate the uncertainty of dominant factors influencing the degree of consolidation in the radial consolidation theories. Based on the developed probabilistic analysis model, sensitivity study of those factors was performed to find their trends of affecting the degree of consolidation in the vertical drain method. Various radial consolidation theories, proposed by Barron(1948), Hansbo(1979), Yoshikuni(1979) and Onoue(1988), were used for this parametric study with the influencing factors such as size of smear zone, reduction ratio of permeability in the smear zone, discharge capacity, permeability for horizontal flow and coefficient of consolidation for horizontal flow. As results of this sensitivity study, for the given consolidation theory, contribution of each factor to the degree of consolidation was figure out and compared to each other. For the given value of each factor, the sensitivity to the degree of consolidation in the various theories was evaluated and their applicability and limitations were assessed.

• Hwankyungkyoyuk
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• v.19 no.3
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• pp.138-149
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• 2006

The purpose of this study was to develop the environmental sensitivity(ES) measurement instrument and to apply for middle school students. The questionnaire was developed to evaluate ES. The developed questionnaire consists of 15 items in 5 categories. Each item of the instrument was developed through the conceptional analysis of the definition of ES. The 5 categories included natural environment, activity at natural environment, artificial environment, environmental pollution, environmental destruction. Data for this study were collected from 397 middle school students including 46 environmental class and 351 non-environmental class students. It was found that the developed instrument to measure ES was valid and reliable. Reliability coefficient, Cronbach $\alpha$ was 0.75. Using the developed instrument of ES, the ES was measured for the students of experimental group to which a inqury-based EE model was applied. The result was that the effect of ES of the students of the experimental group was not statistically significant. Futher research is needed related to the EE model based on the inquiry learning model and measurement of environmental sensitivity.

• Water for future
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• v.21 no.4
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• pp.407-414
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• 1988

The purpose of this paper is to study the following ; (1) how the stability and sensitivity of a given stream water quality model can be analyzed theoretically by means of the stability theory and the sensitivity theory, and (2) point out that the results of this study prove that numerical analysis for the given stream water quality model is reliable, and the model is sensitive for the variations of parameters. A stability theory which is described by the infinite Fourier series is used to analyze the numerical scheme of the model. The numerical shheme is used a backward implicit scheme. a sensitivity theory which is described by the first order linear vector equation is used to analyze theoretically the effect of variations of water quality parameters such as BOD loads, flow rate, temperature. The results of sensitivity theory are of general applicability and are presented in a analytical form. The results of this study seems to be satisfactory for the reliability of stream water quality model with respect to the numerical scheme and the variations of the water quality parameters.

• Journal of Advanced Marine Engineering and Technology
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• v.22 no.4
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• pp.560-568
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• 1998

Recently to develop an automobile with better properities many researches and investments have been executed. In this paper we intend to improve the automobile properties by reducing the weight of the engine without changing the dynamic characteristics. At first the vibration analysis by the Substructure Synthesis Mehtod and the exciting test of the engine model performed to confirm the reliability of the analyzing tools. And the weight minimiza-tion is performed by the Sensitivity Analysis and the Optimum Structural Modificationl. To decrease the engine weight ideally the weight of the parts with the low sensitivity is to cut mainly and the changing quantity of the natural frequency by the cut is to be recovered by the weight modification of the parts with the high sensitivity. As actually the mathematical unique solution for the homogeneous problem(i. e. 0 object func-tion problem)does not exist we redesign the engine block with much thinner initial thickness and recover the natural frequencies and natural modes of original structure by the sensitivity analy-sis and then observe the Frequency Response Function(FRF) for the interesting points. In this analysis the original thickness of the engine model is 8mm and the redesigned initial thicknesses are 5mm and 6mm, And the number of the interesting natural frequencies are 1, 2, 3, 4 and 5 respectively.

• The Journal of Asian Finance, Economics and Business
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• v.8 no.5
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• pp.707-715
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• 2021

This article examines the potential impact of the Covid-19 Lockdown on earnings manipulation and stock market sensitivity to earnings announcements. It also explores the effects of earnings manipulation after the COVID-19 outbreak on the share price sensitivity to the earnings disclosures. The study uses a quantitative method to analyze the financial data consisting of 87 firms listed on the Iraq Stock Exchange for the period from 2018 to 2020, which constitutes a total of (174 observations). We used Ohlson (1995) model to estimate financial market reaction and sensitivity to earnings manipulation fluctuations and accounting information. The results show that companies practice earnings manipulation to maintain earnings over a time series, which means a negative impact of earnings manipulation on all earnings measures' value relevance (EPS, BVS, and CFS). Accordingly, earnings manipulation negatively influences investor behavior in the financial market, based mainly on financial reporting. The value relevance of financial reports has also decreased because of the COVID-19 outbreak and related economic Lockdown. These results reflect a long-term adverse impact of earnings manipulation on investor behavior and financial statements reliability.