• 대기
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• 제25권1호
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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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• 제31권11호
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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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• 제20권2호
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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.

• 전자공학회논문지
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• 제51권12호
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• pp.140-149
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• 2014

최근 초고해상도 디스플레이의 개발로 영상의 화질 향상에 관한 연구가 활발히 이루어지고 있다. 기존의 화질 향상 방법은 대비와 디테일을 동시에 향상시키는 과정에서 경계 영역을 중심으로 대비의 역전현상이 발생하는 문제가 있다. 본 논문은 영상의 화질 향상을 향상하는 과정에서 계층적 정보와 경계 영역의 밝기편차를 고려함으로써 이를 해결하고자 하였다. 먼저 크기가 다른 계층들에 대하여 블록의 크기별로 대비를 향상한다. 다음으로 각 블록별 경계영역을 계산하고 해당 영역의 밝기 변화율을 기반으로 가중치를 결정한다. 결정된 가중치를 이용하여 디테일 향상을 수행한다. 다양한 영상에 대하여 실험한 결과 제안한 알고리즘의 대비 및 디테일이 우수함을 확인하였다.

• 대한가정학회지
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• 제36권4호
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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.

• 한국학교ㆍ지역보건교육학회지
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• 제19권2호
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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.

• 품질경영학회지
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• 제48권3호
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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.

• 품질경영학회지
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• 제21권2호
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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.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2002년도 Proceedings of the International Welding/Joining Conference-Korea
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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.

• 한국정밀공학회지
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• 제26권4호
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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.