• Atmosphere
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• v.25 no.1
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• pp.19-30
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• 2015

The Ka-band cloud radar (KCR) has been operated by the National Institute of Meteorological Research (NIMR) of Korea Meteorological Administration (KMA) at Boseong National Center for Intensive Observation of severe weather since 2013. Evaluation of data quality is an essential process to further analyze cloud information. In this study, we estimate the measurement error and the sampling uncertainty to evaluate data quality. By using vertically pointing data, the statistical uncertainty is obtained by calculating the standard deviation of each radar parameter. The statistical uncertainties decrease as functions of sampling number. The statistical uncertainties of horizontal and vertical reflectivities are identical (0.28 dB). On the other hand, the statistical uncertainties of Doppler velocity (spectrum width) are 2.2 times (1.6 times) larger at the vertical channel. The reflectivity calibration of KCR is also performed using X-band vertically pointing radar (VertiX) and 2-dimensional video disdrometer (2DVD). Since the monitoring of calibration values is useful to evaluate radar condition, the variation of calibration is monitored for five rain events. The average of calibration bias is 10.77 dBZ and standard deviation is 3.69 dB. Finally, the statistical characteristics of cloud properties have been investigated during two months in autumn using calibrated reflectivity. The percentage of clouds is about 26% and 16% on September to October. However, further analyses are required to derive general characteristics of autumn cloud in Korea.

• Bulletin of the Korean Chemical Society
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• v.31 no.11
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• pp.3139-3144
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• 2010

A model system has been established for the evaluation of the uncertainty of the value from measurements of multiple subsamples by isotope dilution mass spectrometry (IDMS). In this report, we apply this model system for the evaluation of measurement uncertainty in determination of folic acid in infant formula. Five subsamples were analyzed by IDMS. The mean of the measurement results of the five subsamples was assigned as the final measurement value. The standard deviation (s) of the results from five subsamples was attributable to repeatability of the measurement. The uncertainty components in the IDMS measurement methods were categorized into two groups. Group I includes uncertainty components which give common systematic effects to all subsamples and do not contribute to the variation among multiple measurements (repeatability). Group II includes uncertainty components that give random effects on the measurement results, and are related with the measurement repeatability. These random effects are attributed to s. Therefore, the uncertainty of the final value was calculated by combining the standard deviation of the mean of multiple measurements, $s/{\surd}n$ (where n = 5), and the measurement uncertainty associated with the uncertainty components that give systematic effects.

• Journal of the Optical Society of Korea
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• v.20 no.2
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• pp.314-320
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• 2016

The glass thermal forming process provides a high volume, low cost approach to producing aspherical reflectors for x-ray optics. Thin glass sheets are shaped into mirror segments by replicating the mold shape at high temperature. Heating parameters in the glass thermal slumping process are crucial to improve surface quality of the formed glass. In this research, the heating process of a thermal slumping glass sheet on a concave parabolic mold was simulated with the finite-element method (FEM) to investigate the effects of heating rate and soaking temperature. Based on the optimized heating conditions, glass samples 0.5 mm thick were formed in a furnace with a steel concave parabolic mold. The figure errors of the formed glass were measured and discussed in detail. It was found that the formed glass was not fully slumped at the edges, and should be trimmed to achieve better surface deviation. The root-mean-square (RMS) deviation and peak-valley (PV) deviation between formed glass and mold along the axial direction were 2.3 μm and 4.7 μm respectively.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.12
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• pp.140-149
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• 2014

Image enhancement has become an important area of study with the recent development of hi-fidelity devices, such as UHD displays. While conventional methods are able to enhance the image contrast and detail, this sometimes results in contrast reversion in boundary region. Therefore, this paper proposes the use of multi-layers and intensity deviation in boundary areas to enhance the perceived image quality. First, the image contrast of individual blocks is enhanced using multi-layers with different sizes. After calculating the block boundaries, weights are then determined based on the intensity deviation and used to enhance the image detail. Experiments with several test images confirm that the proposed algorithm is superior that image contrast and detail to conventional methods.

• Journal of the Korean Home Economics Association
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• v.36 no.4
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• pp.189-198
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• 1998

The purpose of this study was to examine the children's social competence according to not only the day care centers overall, but subordinate quality. Subiects for this study involved auditions, observations, and the use of questionnaires. By using a SAS statistic program, the average, and the standard deviation, and the One-way ANOVA/Duncan test were obtained from the study: The following results were obtained from the study: 1. For the test of the day care centers overall and subordinate quality, an average of the centers whole quality scored 2.56 and the subordinate quality ranged from 1.94 to 2.88. 2. When the children's social copetence according to the day care centers overall quality was examined, high-quality centers ranked higher social competence of children than that of low-quality centers. 3. Finally, the children's social competence according to the day care centers subordinate quality was inspected. Here, the results showed a significat difference in the 'planning and operation of curriculum' and the 'interaction between terachers and children'. not unlike the above results, high subordinate-quality day care centers scored higher social competence of children than that of low subordinate-quality day care centers.

• The Journal of Korean Society for School & Community Health Education
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• v.19 no.2
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• pp.43-52
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• 2018

Objects: In this study, we analyzed the correlation between stress and depression related to the quality of life of one elderly household, and analyzed the influence of stress and depression on the quality of life. In this study, I tried to make a plan for improving the quality of life for one elderly. Methods: In this study, the frequency and percentage according to the general characteristics of one elderly household were frequency analyzed. And the mean and standard deviation of stress, depression, quality of life were analyzed on average. And continuous analysis of stress, depression, quality of life, etc., conducted a technical analysis. Relationship to stress, depression, quality of life, correlation analysis was done. The effect of stress and depression on the quality of life was linear regression analysis. SPSS Version 23.0 was used for analysis. Result: Increased stress and increased depression in elderly single households was a static (+) correlation. And the results of the regression analysis showed that the higher the stress and depression of one elderly household, the lower the quality of life. Conclusion: For the improvement of the quality of life of one elderly household, the government should support stress and depression prevention programs according to sex, age, number of chronic diseases.

• Journal of Korean Society for Quality Management
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• v.48 no.3
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• pp.481-492
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• 2020

Purpose: The purpose of this study was to minimize the difference between color of fibers of combat uniforms occurring depending on the type of dye or process of each manufacturer. Methods: Color difference between combat uniforms made from different manufacturers in mass production by lot was analyzed using spectrophotometer and calculated by color difference formula. Results: By the results of analyzing the color difference between combat uniforms made from different manufacturers with moving average and time series analysis, the feedback to each manufacturer was given. Conclusion: By this study, the color deviation of combat uniforms from different manufacturers was improved to be reduced.

• Journal of Korean Society for Quality Management
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• v.21 no.2
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• pp.61-70
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• 1993

The concept of producer's tolerance, in contrast to the consumer's tolerance, is a natural consequence of continuous loss functions. It is based on the premise that any unit product whose quality characteristic deviated from its traget value inflicts a loss, and that this less is a continuous monotonically increasing function of the magnitude of deviation. This concept of the emphasis on loss function to improve quality of products on the side of customer is introduced by Taguchi. This paper considers the problem of determining the optimum producer's tolerance by continous loss fuction of Taguchi and proposes a probablistic model for the problem. The difference between the proposed probablistic approach and the approach taken in Taguchi is also pointed out.

• Proceedings of the KWS Conference
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• 2002.10a
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• pp.606-611
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• 2002

Welding using lasers can be mass-produced in high speed. In the laser welding, performing real-time monitoring system of the welding quality is very important in enhancing the efficiency of welding. In this study, the plasma and molten metal which are generated during laser welding were measured using the UV sensor and IR sensors. The results of laser welding were classified into five categories such as optimal heat input, little low heat input, low heat input, partial joining due to gap mismatch, and nozzle deviation. Also, a system was formulated which uses the measured signals with a fuzzy pattern recognition method which is used to perform real-time evaluation of the welding quality and the defects which can occur in laser welding.

• Journal of the Korean Society for Precision Engineering
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• v.26 no.4
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• pp.128-133
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• 2009

Focused-ion-beam (FIB) system is capable of both machining and measuring in nano-scale; hence nano-scale focusing quality is important. This paper investigates design parameters of two electrostatic lenses in order to achieve the best ion beam focusing performance. Commercial SIMION simulator is used to optimize the dimensions of the condenser and objective lenses and investigate the influence of assembly error on focusing quality The simulation results show that the beam focusing quality is not influenced by angle deviation within ${\pm}0.02\;deg$ and geometrical eccentricity within ${\pm}50$ micrometers.