• Nuclear Engineering and Technology
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• v.21 no.4
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• pp.294-301
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• 1989

The Axial Power Distribution Monitoring System(APDMS) program was developed to calculate a detailed axial power distribution using two-level excore detector, cold leg temperature and control rod position signals. The unnormalized two-level excore detector signals were corrected for the rod shadowing factor determined by control rod position and for the temperature shadowing factor calculated based on cold leg temperature. A shape annealing matrix was then applied to the corrected excore detector response to yield peripheral power. After the core average power was obtained using linear relationship bet-ween core average and peripheral power, the boundary point power correction coefficient was applied to core average power in order to obtain boundary power for both upper and lower core axial boundaries. Then, the axial power distribution was synthesized by spline approximation. In spite of burnup, power level, control rod postion and axial offset changes, the comparisons of axial power distributions between BOXER simulation program and APDMS results showed good agreements within 5% root mean square error for Kori Unit 3 Cycle 4.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.25 no.9
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• pp.912-918
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• 2014

In this paper, a VHF band multi channel phase discriminator for direction finding equipment using tripple baseline interferometer technique is proposed. In order to measure simultaneously phase difference between IF(Intermediate Frequency) signals of the direction finding equipment, phase discriminator was designed to have parallel structure with multi channel, the phase correlator of phase discriminator was designed with I, Q mixer for reducing number of components. And digital LUT(Look Up Table) was applied for compensating error of phase discriminator due to phase unbalance of RF components. The measured phase accuracy of fabricated phase discriminator was 2 degree RMS(Root Mean Square) at 30 dB SNR condition, which is superior to the phase accuracy of conventional product.

• Journal of Convergence for Information Technology
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• v.7 no.3
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• pp.97-103
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• 2017

In this paper, we aim to investigate the generalization of ZRC codes by performing performance analysis on various coding rates and channel conditions of Zero Reduction Code (ZRC) for dimming control in VLC system. Simulation results show that the ZRC codes with relatively high coding rate achieve the enhanced BER performance as the RMS (Root Mean Square) delay spread value increases in the NLOS channelse. Therefore, it is expected that the designing of the dimming control technology using ZRC in the future visible light communication system will help to determine the coding rate according to the channel state through the analysis result in this study.

• Journal of Korean society of Dental Hygiene
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• v.18 no.6
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• pp.979-986
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• 2018

Objectives: The purpose of this study was to investigate the relationship between socioeconomic status and periodontal disease. Methods: The data used for the analysis were obtained from the sixth Korean National Health and Nutrition Examination Survey (2015). A total of 5,632 adults, aged over 19 years, were included in the study. This study analyzed data relating to socioeconomic status and health behaviors. The socioeconomic status was defined as an exogenous factor. Periodontal disease was the endogenous variable. Health behavior was a mediating variable. The study hypotheses were tested using Structural Equation Modeling analysis with Mplus 7.0 software. Results: According to the model fit test, the associated root-mean-square error was 0.05 (90% CI: 0.046-0.059); comparative fit index was 0.93; Tucker-Lewis index was 0.88; and standardized root-mean-square residual was 0.03. We found that socioeconomic status had significant effects on health behaviors (${\beta}=0.304$, p<0.001) and periodontal disease (${\beta}=-0.289$, p=0.001). Moreover, health behaviors had significant effects on periodontal diseases (${\beta}=0.143$, p<0.001). The analysis of a possible relationship between socioeconomic status and periodontal disease using path analysis demonstrated health behaviors difficulties, along with direct and indirect effects, further increased the risk of periodontal disease. Conclusions: The findings suggest that future interventions for the prevention of periodontal disease should consider health behavior.

• The Journal of the Korea Contents Association
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• v.21 no.5
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• pp.996-1003
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• 2021

The purpose of this study is to evaluate the reliability of repeated measurements of several dental scanners. Blue-lighted scanners, white-light scanners and optical-type scanners are used in the study of repeatability in this study. The measurement results were calculated as root mean square (RMS) and the significance level was confirmed by applying the 1-way ANOVA statistical technique (𝛼=.05). According to the statistical analysis, the scanner with the largest RMS value was Z-opt group (38.2 ㎛. Next, D-white was 35.2 ㎛ and the group with the lowest RMS value was I-blue (34.1 ㎛). The comparison of RMS means between each group was not significant (p>.05). From this result, the blue light had the lowest error in repeatability of dental scanners, but no statistical significance. The conclusion of this study is that the study results are clinically acceptable.

• Journal of Korean Academy of Nursing
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• v.53 no.6
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• pp.652-665
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• 2023

Purpose: This study aimed to develop a nursing clinical judgment scale (NCJS) and verify its validity and reliability in assessing the clinical judgment of nurses. Methods: A preliminary instrument of the NCJS comprising 38 items was first developed from attributes and indicators derived from a literature review and an in-depth/focus interview with 12 clinical nurses. The preliminary tool was finalized after 7 experts conducted a content validity test based on a data from a preliminary survey of 30 hospital nurses in Korea. Data were collected from 443 ward, intensive care unit, emergency room nurses who voluntarily participated in the survey through offline and online for the verification of the construct validity and reliability of the scale. Results: The final scale comprised 23 items scored on a 5-point Likert scale. Six factors - integrated data analysis, evaluation and reflection on interventions, evidence on interventions, collaboration among health professionals, patient-centered nursing, and collaboration among nurse colleagues - accounted for 64.9% of the total variance. Confirmatory factor analysis supported the fit of the measurement model, comprising six factors (root mean square error of approximation = .07, standardized root mean square residual = .04, comparative fit index = .90). Cronbach's α for all the items was .92. Conclusion: The NCJS is a valid and reliable tool that fully reflects the characteristics of clinical practice, and it can be used effectively to evaluate the clinical judgment of Korean nurses. Future research should reflect the variables influencing clinical judgment and develop an action plan to improve it.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.37 no.2
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• pp.303-310
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• 2017

Evapotranspiration is a significant hydrologic quantity for understanding the amount of available water resource evaluation, water balance analysis, water circulation and energy circulation. Various methods have been developed for estimating the evapotranspiration using data observed at meteorological observatories. Especially, the focus of methods has been on the complementary relationship that the actual evapotranspiration is equal to the difference between the twice of evapotranspiration in the wet condition and the potential evapotranspiration. The Granger and Gary (GG) method is an empirical formula that can be used to estimate the evapotranspiration using only empirical parameters based on the complementary relationship and using only the net radiation and temperature of the region. In this study, we compared the evapotranspiration data observed at 10 sites in Asia within the dataset of FLUXNET2015, with the evapotranspiration calculated by GG method. The evapotranspiration in inland area was estimated more accurately than that of coastal area. Simulated Annealing (SA) was used for the coastal area to modify the parameters. Using the modified GG method, we could improve the statistics such as root mean square error, the coefficient of determination ($R^2$), and the mean absolute ${\mid}BIAS{\mid}$ of the evapotranspiration estimation in coastal area.

• Journal of the Korean Association of Geographic Information Studies
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• v.22 no.4
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• pp.197-214
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• 2019

In this study, the correlation analysis was conducted between observed air temperature (maximum, minimum, and mean air temperature) and the daytime and nighttime data of Terra/Aqua MODIS LST(Moderate Resolution Imaging Spectroradiometer Land Surface Temperature) for 86 weather stations. All the data of the recent 11 years from 2008 to 2018 were prepared with daily base. In particular, the characteristics of the cold and heat waves incidence period in 2018 were analyzed. The correlation analysis was performed using the Pearson correlation coefficient(R) and root mean square error(RMSE). As a result of time series analysis, the trend between observed air temperature and MODIS LST were similar, showing the correlation above 0.9 in maximum temperature, above 0.8 in mean and minimum temperature. Especially, the maximum temperature was found to have the highest accuracy with Terra MODIS LST daytime, and the minimum temperature had the highest correlation with Terra MODIS LST nighttime. During the cold wave period, both Terra and Aqua MODIS LST showed higher correlations with nighttime data than daytime data. For the heat wave period, the Aqua MODIS LST daytime data was good, but the overall R was below 0.5. Additional analysis is necessary for further study considering such as land cover and elevation characteristics.

• Ecology and Resilient Infrastructure
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• v.5 no.4
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• pp.246-256
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• 2018

In order to analyze hydraulic characteristics of discharge coefficient, hydraulic jump height, and hydraulic jump length, accompanied sediment transport, in the under-flow type vertical lift gate, the hydraulic model experiment and dimensional analysis were performed. The correlations between Froude number and hydraulic characteristics were schematized according to the presence and absence of sediment transport; the correlation of hydraulic characteristics and non-dimensional parameters was analyzed and multiple regression formulae were developed. In the hydraulic characteristics accompanied the sediment transport, by identifying the aspect different from the case that the sediment transport is absent, we verified that it is necessary to introduce variables that can express the characteristics of sediment transport. The multiple regression equations were suggested and each determination coefficient appeared high as 0.749 for discharge coefficient, 0.896 for hydraulic jump height, and 0.955 for hydraulic jump length. In order to evaluate the applicability of the developed hydraulic characteristic equations, 95% prediction interval analysis was conducted on the measured and the calculated by regression equations, and it was determined that NSE (Nash-Sutcliffe Efficiency), RMSE (root mean square), and MAPE (mean absolute percentage error) are appropriate, for the accuracy analysis related to the prediction on hydraulic characteristics of discharge coefficient, hydraulic jump height and length.

• Wind and Structures
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• v.19 no.4
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• pp.371-387
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• 2014

Probability plotting positions are popular and used as the basis for distribution fitting and for inspecting the quality of the fit because of its simplicity. The plotting positions that lead to excellent approximation to the mean of the order statistics should be used if the objective of the fitting is to estimate quantiles. Since the mean depends on the sample size and is not amenable for simple to use closed form solution, many plotting positions have been presented in the literature, including a new plotting position that is derived based on the weighted least-squares method. In this study, the accuracy of using the new plotting position to fit the Gumbel distribution for estimating quantiles is assessed. Also, plotting positions derived by fitting the mean of the order statistics for all ranks is proposed, and an approximation to the covariance of the order statistics for the Gumbel (and Weibull) variate is given. Relative bias and root-mean-square-error of the estimated quantiles by using the proposed plotting position are shown. The use of the proposed plotting position to estimate the quantiles of annual maximum wind speed is illustrated.