• Journal of the Korean Data and Information Science Society
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• v.26 no.1
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• pp.41-53
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• 2015

In meteorological field, many researchers have tried to develop micro scale weather analysis modules for providing real-time weather information service in the metropolitan area. This effort enables us to cope with various economic and social harms coming from serious change in the micro meteorology of a metropolitan area due to rapid urbanization such as quantitative expansions in its urban activity, growth of population, and building concentration. The accuracy of the micro scale weather analysis modules (MSWAM) directly related to usefulness and quality of the real-time weather information service in the metropolitan area. This paper design a evaluation system along with verification tools that sufficiently accommodate spatio-temporal characteristics of the outputs of the MSWAM. For this we proposes a test for the equality of mean vectors of the output series of the MSWAM and corresponding observed time series by using a spectral analysis technique. As a byproduct, a time series cluster analysis method, using a function of the test statistic as the distance measure, is developed. A real data application is given to demonstrate the utility of the method.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.4
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• pp.1295-1302
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• 2013

The structural deformed shape is important information to structural analysis. If the sufficient measuring points are secured at the structural monitoring system, reasonable and accurate structural deformation shapes can be obtained and structural analysis is possible using this deformation. However, the accurate estimation of the global structural shapes might be difficult if sufficient measuring points are not secure under cost limitations. In this study, SFSM-LS algorithm, the economic and effective estimation method for the structural deformation shapes with limited displacement measuring points is developed and suggested. In the suggested method, the global structural deformation shape is determined by the superposition of the pre-investigated structural deformed shapes obtained by preliminary FE analyses, with their optimum weight factors which lead minimization of the estimate errors. 2-span continuous bridge model is used to verify developed algorithm and parametric studies are performed. By the parametric studies, the characteristics of the estimation results obtained by the suggested method were investigated considering essential parameters such as pre-investigated structural shapes, locations and numbers of displacement measuring points. By quantitative comparison of estimation results with the conventional methods such as polynomial, Lagrange and spline interpolation, the applicability and accuracy of the suggested method was validated.

• Proceedings of the Korean Society of Medical Physics Conference
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• 2002.09a
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• pp.407-410
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• 2002

Monochromatic x-ray CT has several advantages over conventional CT, which utilizes bremsstrahlung white x-rays from an x-ray tube. There are several methods to produce such monochromatic x-rays. The most popular one is crystal diffraction monochromatization, which has been commonly used because of the fact that the energy spread is very narrow and the energy can be changed continuously. The alternative method is the use of fluorescent x-ray, which has several advantages such as large beam size and fast energy change. We have developed a parallel-beam and a fan-beam monochromatic x-ray CT, and compared some characteristics such as accuracy of CT numbers between those systems. The fan beam monochromatic x-rays were generated by irradiating target materials by incident white x-rays from a bending magnet beam line NE5 in 6.5 GeV Accumulation Ring at Tukuba. The parallel beam monochromatic x-rays were generated by using a silicon double crystal monochromator at the bending magnet beam line BL-20BM in Spring-8. A Cadmium telluride (CdTe) 256 channel array detector with 512mm sensitive width capable of operating at room temperature was used in the photon counting mode. A cylindrical phantom containing eight concentrations of gadolinium was used for the fan beam monochromatic x-ray CT system, while a phantom containing acetone, ethanol, acrylic and water was used for the parallel monochromatic x-ray CT system. The linear attenuation coefficients obtained from CT numbers of those monochromatic x-ray CT images were compared with theoretical values. They showed a good agreement within 3%. It was found that the quantitative measurement can be possible by using the fan beam monochromatic x-ray CT system as well as a parallel beam monochromatic X-ray CT system.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.40 no.1
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• pp.37-44
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• 2014

Preservatives such as paraben, phenoxyethanol, and chlorphene are commonly used in cosmetics thanks to cheap price and good antiseptic effect. Recently, consumers' concerns about their possible toxicity and skin irritation forced them to be replaced with straight 1,2-alkanediols. However, as the alkanediols may also irritate skin, limited amount of them should be used in cosmetics. Three 1,2-alkanediols including 1,2-pentanediol, 1,2-hexanediol, and 1,2-octanediol in cosmetics were analyzed simultaneously by gas chromatogrphy with flame ionization detector. As a result of method validation, the specificity was confirmed by the calibration curves of 1,2-pentanediol, 1,2-hexanediol, and 1,2-octanediol showing good linearity correlation coefficient of above 0.999 over the concentration range of $100{\sim}1,200{\mu}g/g$. The limit of detection (LOD) and quantification (LOQ) of 1,2-pentanediol, 1,2-hexanediol, and 1,2-octanediol were 31, 40, and $19{\mu}g/g$ and 98, 108, and $57{\mu}g/g$, respectively. The precision (Repeatability) of the amount in cosmetics showed less than 2.0%. Relative Standard Deviation (% RSD) and the Accuracy (% recovery) of the amount in cosmetics showed 99.3 ~ 103.3, 99.4 ~ 106.7, 97.5 ~ 107.3% respectively. As a result, simultaneous analysis of antimicrobial three 1,2-alkanediols in cosmetics were possible. This method can be utilized in accurate quantitative analysis of 1,2-alkanediols in cosmetics.

• The Journal of Engineering Geology
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• v.14 no.4 s.41
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• pp.443-450
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• 2004

This study developed a prediction model of debris flow to predict a landslide probability on natural terrain composed of the Tertiary sedimentary and volcanic rocks using a logistic regression analysis. The landslides data were collected around Pohang, Gyeongbuk province where more than 100 landslides were occurred in 1998. Considered with basic characteristics of the logistic regression analysis, field survey and laboratory soil tests were performed for both slided points and not-slided points. The final iufluential factors on landslides were selected as six factors by the logistic regression analysis. The six factors are composed of two topographic factors and four geologic factors. The developed landslide prediction model has more than $90\%$ of prediction accuracy. Therefore, it is possible to make probabilistic and quantitative prediction of landslide occurrence using the developed model in this study area as well as the previously developed model for metamorphic and granitic rocks.

• Journal of Korea Water Resources Association
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• v.41 no.9
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• pp.943-958
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• 2008

This study employs Bayesian regression analysis for fitting discharge rating curves. The parameter estimates using the Bayesian regression analysis were compared to ordinary least square method using the t-distribution. In these comparisons, the mean values from the t-distribution and the Bayesian regression are not significantly different. However, the difference between upper and lower limits are remarkably reduced with the Bayesian regression. Therefore, from the point of view of uncertainty analysis, the Bayesian regression is more attractive than the conventional method based on a t-distribution because the data size at the site of interest is typically insufficient to estimate the parameters in rating curve. The merits and demerits of the two types of estimation methods are analyzed through the statistical simulation considering heteroscedasticity. The validation of the Bayesian regression is also performed using real stage-discharge data which were observed at 5 gauges on the Anyangcheon basin. Because the true parameters at 5 gauges are unknown, the quantitative accuracy of the Bayesian regression can not be assessed. However, it can be suggested that the uncertainty in rating curves at 5 gauges be reduced by Bayesian regression.

• The KIPS Transactions:PartD
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• v.13D no.6 s.109
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• pp.823-832
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• 2006

The Purpose of Similarity(Reproduction) Degree Appraisal is to determine the equality or similarity between two programs and it is a system that presents the technical grounds of judgment which is necessary to support the resolution of software intellectual property rights through expert eyes. The most important things in proceeding software appraisal are not to make too much of expert's own subjective judgment and to acquire the accurate-appraisal results. However, up to now standard research and development for its systematic techniques are not properly made out and as different expert as each one could approach in a thousand different ways, even the techniques for software appraisal types have not exactly been presented yet. Moreover, in the analyzing results of all the appraisal cases finished before, through a practical way, we blow that there are some damages on objectivity and accuracy in some parts of the appraisal results owing to the problems of existing appraisal procedures and techniques or lack of expert's professional knowledge. In this paper we present the model for the standardization of software-similarity-appraisal techniques and objective-evaluation methods for decreasing a tolerance that could make different results according to each expert in the same-evaluation points. Especially, it analyzes and evaluates the techniques from various points of view concerning the standard appraisal process, setting a range of appraisal, setting appraisal domains and items in detail, based on unit processes, setting the weight of each object to be appraised, and the degree of logical and physical similarity, based on effective solutions to practical problems of existing appraisal techniques and their objective and quantitative standardization. Consequently, we believe that the model for the standardization of software-similarity-appraisal techniques will minimizes the possibility of mistakes due to an expert's subjective judgment as well as it will offer a tool for improving objectivity and reliability of the appraisal results.

• Journal of Korean Society for Atmospheric Environment
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• v.33 no.1
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• pp.31-44
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• 2017

The aim of this study is to evaluate the accuracy and variability of the oak pollen concentrations over the Seoul metropolitan region (SMR) simulated by the Community Multiscale Air Quality (CMAQ)-based pollen dispersion model, which is the CMAQ-pollen model integrated with the improved oak pollen emission model(PEM-oak). The PEM-oak model developed is based on hourly emission flux parameterization that includes the effects of plant-specific release, meteorological adjustment, and diurnal variations of oak pollen concentrations. A 33 day-run for oak pollen simulation was conducted by the CMAQ-pollen model with a 3 km spatial resolution for the SMR during the 2014 spring pollen season. Modeled concentrations were evaluated against the hourly measurements at three Burkard sampling sites. Temporal variations of oak concentrations were largely well represented by the model, but the quantitative difference between simulations and measurements was found to be significant in some periods. The model results also showed that large variations in oak pollen concentrations existed in time and space and high concentrations in the SMR were closely associated with the regional transport under strong wind condition. This study showed the effective application of the CMAQ-pollen modeling system to simulate oak pollen concentration in the SMR. Our results could be helpful in providing information on allergenic pollen exposure. Further efforts are needed to further understand the oak pollen release characteristics such as interannual variation of the oak pollen productivity and its spatio-temporal flowering timing.

• Journal of Korean Society of Water and Wastewater
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• v.27 no.6
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• pp.827-836
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• 2013

Due to the stringent drinking water quality, formaldehyde will be included in Korean drinking water standard from year 2014. However, its standard analytical method has not yet been established. This study compares two analytical methods, DNPH-LC and ACFAS with respect to their analysis principles, Method Detection Limit (MDL), Limit Of Quantitation(LOQ), precision, accuracy, reproducibility, convenience, number of samples analyzed per hour and analysis cost. These methods measure absorption intensity at 360 nm by using HPLC after DNPH-derivatization (DNPH-LC) and at 410 nm by using Automated Continuous Flow Absorption Spectrophotometer (ACFAS), respectively. Reproducibility was tested by repeating the analysis 7 times using a standard solution for each method. For DNPH-LC method, MDL was $0.5{\mu}g/L$, LOQ was $1.58{\mu}g/L$ with standard deviation of $0.16{\mu}g/L$. For ACFAS method, they were $0.27{\mu}g/L$, $0.85{\mu}g/L$L with standard deviation of $0.09{\mu}g/L$, respectively. Both methods satisfied the requirement set by the Korean drinking water quality standard. Complexity of sample pretreatment procedure for DNPH-LC method may cause large error and, consequently, the analytical result will depend on the level of skill of analyst. In contrast, ACFAS method which used only one reagent equipped with an automated injection device showed little analytical error. It costs about $5.00 and $1.00 for one sample to analyze by the DNPH-LC method and the ACFAS method, respectively. Compared to the DNPH-LC method, ACFAS method provided more reliable analytical results. In terms of convenience, easiness and analytical cost, ACFAS method was demonstrated to be superior to the DNPH-LC method. The results of this study suggested that the ACFAS method could be adapted as a proper method for determining formaldehyde content in drinking water.

• Korean Journal of Food Science and Technology
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• v.45 no.3
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• pp.279-284
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• 2013

A quantitative method using ultra performance liquid chromatography with a photodiode array detector (UPLCPDA) was established for the analysis of 2 major plant metabolites: ${\beta}$-asarone and ${\alpha}$-asarone from Acorus gramineus, A. tatarinowii, A. calamus and Anemone altaica, and their contents are compared with other herbs of Acorus species. The method was validated according to the International Conference on harmonization (ICH) guideline for validation of analytical procedures with respect to precision, accuracy, and linearity. The average content of ${\beta}$-asarone in Acorus gramineus was significantly higher than that in others, with the second highest concentration observed in A. tatarinowii, and only a trace amounts found in A. calamus and Anemone altaica. In contrast, the average content of ${\alpha}$-asarone in A. calamus was the highest, followed by that in Acorus gramineus and A. tatarinowii. principle component analysis (PCA) confirmed that ${\beta}$-asarone and ${\alpha}$-asarone content differed among the species. These results suggest that this UPLC-PDA method can be considered as good quality control criteria for Acorus gramineus.