• Korean Journal of Soil Science and Fertilizer
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• v.39 no.3
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• pp.144-150
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• 2006

Chemical characteristics and their interrelationships of 156 soils included by 74 sandy loam and 82 loam soils collected from plastic film house in Chungbuk area were investigated from 1998 to 2001. Seventeen chemical properties including pH, organic matter (OM), electrical conductivity (EC), inorganic nitrogen, available phosphorus, exchangeable cations, CEC, etc., were analyzed by correlation, standardized partial regression coefficient, and principal factor analysis. Standardized partial regression coefficients of chemical properties were estimated to determine the degree of contribution of EC and OM contents in soils. Principal factor analysis was applied to classify the studied chemical properties into different groups having similar chemical properties. The pH of experimental soils ranged from 4.24 to 7.14 and 4.95 to 7.35 for loam and sandy loam soils, respectively. The EC of soils varied from 0.93 to $15.65dS\;m^{-1}$ for loam and $0.91{\sim}22.30dS\;m^{-1}$ for sandy loam soils, respectively with significant differences among them. The EC measured by 1:5 $H_2O$ dilution method and saturation method were significantly related with 8.163 and 8.599 as the slopes of regression equation for loam and sandy loam soils, respectively. These slopes more than 8.0 in this regression equation was higher than the slope of 5.0 that is estimated from dilution coefficient suggesting that EC measured by 1:5 dilution method might be erratic. The standardized partial regression coefficient of different chemical properties for the estimation of EC was in the order of $NO_3{^-}$ > $Cl^-$ > OM > exchangeable Mg for loam soils and $NO_3{^-}$ > exchangeable Mg > $Cl^-$ for sandy loam soils. Contribution order of the chemical properties based on standardized partial regression coefficient differed 1:5 dilution method and saturation method, indicating that different chemical compounds might be present in the extract solutions of these two methods. Consequently the measurement of EC by saturation method was thought be still better for estimation of chemical property because accuracy of EC measurement by 1:5 dilution method can't be improved by any specific coefficient for adjustment of EC. Regardless of differences in soil textures and extraction methods, correlation coefficients between EC and the other chemical properties were routinely in the order of $NO_3{^-}$ > $Cl^-$ > degree of base saturation > exchangeable Mg > exchangeable Ca > $SO{_4}^{2-}$. The principal factor analysis revealed four factor groups of the chemical properties studied. The groups for sandy loam were as follows; ; 1. salt components, 2. soil reaction components, 3. fixed and adsorption components, 4. CEC components. The groupings of loam soils were similar to sandy loam except that exchangeable Na substituted the CEC of sandy loam.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.38 no.5
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• pp.431-436
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• 2014

Conductance is a concept contrary to flow resistance and is extensively used as a flow index on how easily fluid is transported through a pneumatic pipe or fluid device. However, research on flow conductance is very rare to date, and a systematic investigation is needed for the standardization of pneumatic devices. In the present study, a computational fluid dynamics method was applied to solve the compressible Navier-Stokes equations with two-equation turbulence models. The present CFD results were validated with existing experimental data. The conductance values and friction factors at the inlet and outlet of a pneumatic pipe were used to assess the flow rates. The present results showed that the conductance depends on the pressure ratio at the inlet and outlet of a pipe.

• The Journal of the Acoustical Society of Korea
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• v.30 no.5
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• pp.265-272
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• 2011

In most of the ISF (or LSF) based real time speech codec, SVQ (split vector quantization) method is used to decrease the quantizer complexity and memory size of codebook. However, it produces drawback that the level of correlation between code vectors can not be used during vector splits. This paper presents a new method of adaptive ISF vector quantization, which compensates the drawbacks of SVQ structured quantizer for wideband speech codec. In each different frame, the proposed method makes use of the correlation between splitted vectors by adaptively changing codebook distribution according to ordering property of ISF. The algorithm is evaluated in AMR-WB, and shows about 1.5 bit per frame improvement.

• Journal of the Korean Society for Library and Information Science
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• v.41 no.2
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• pp.335-357
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• 2007

There has been many studies representing intellectual structures with multidimensional scaling(MDS) However MDS configuration is limited in representing local details and explicit structures. In this paper, we identified two components of MDS mapping approach; one is MDS algorithm and the other is preparation of data matrix. Various combinations of the two components of MDS mapping are compared through some measures of fit. It is revealed that the conventional approach composed of ALSCAL algorithm and Euclidean distance matrix calculated from Pearson's correlation matrix is the worst of the compared MDS mapping approaches. Otherwise the best approach to make MDS map is composed of PROXSCAL algorithm and z-scored Euclidean distance matrix calculated from Pearson's correlation matrix. These results suggest that we could obtain more detailed and explicit map of a knowledge domain through careful considerations on the process of MDS mapping.

• The Korean Journal of Nuclear Medicine Technology
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• v.13 no.3
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• pp.31-42
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• 2009

Purpose: As the number of domestic medical institutions installing PET/CT is increasing rapidly, the transfer of PET/CT images among medical institutions is also increasing. Thus, it is necessary to collect the comparative SUV data from several medical institutions' PET/CT systems through a phantom study which semi-quantitatively compares the SUV on one bed, the change scale of the SUV on the slices, and the time of measuring. The phantom study to find differences among the SUVs from various PET/CT offers the opportunity to obtain the reliability of the SUV in PET/CT images. Materials and Methods: Ten PET/CT systems from medical institutions in Korea were used. To obtain the accurate data, the study has been using the radiation detector of Korea Research Institute of Standards and Science to verify. The internal structures of NEMA $phantom^{TM}$ were removed and Six thousand milliliters of distilled water which has 1mCi of $^{18}F$-FDG put into the phantom. The water was properly integrated with $^{18}F$-FDG using magnetic stirrer. The images were acquired at 60, 70, 80, 90, 100, 110 and 120-minutes for 3 minute each. Two hundred square centimeters of region of interests were placed and analyzed. To confirm the usefulness, the correction-table came out from patients' data. Results: The coefficient of variability of the SUV from -11.0 to 9.90 % fell into the range of international standards(${\pm}10%$) along with the SUV on a bed, the change scale of the SUV on the slices, and the time of measuring, except one PET/CT system. Using the data of the differences among the SUVs, we came to withdraw the correction-table ranging from 0.803 to 1.246. The correction-table was confirmed its usefulness through Linear Regression Analysis which was applied to normal cases. Conclusions: Although studies have been made on the variation of the SUV, there is little attention on the standardization of the SUV. Based on this study of the quantitatively comparable data about the SUV accommodating the correction-table, it would help to have more corrective diagnosis.

• Korean Journal of Food Science and Technology
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• v.50 no.4
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• pp.377-382
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• 2018

An HPLC method was developed to quantitate a marker, oxyresveratrol (ORT), for the standardization of mulberry branch extracts (MBE) as a functional ingredient. HPLC was performed on a $C_{18}$ column with a gradient elution using 0.05% $H_3PO_4$ and acetonitrile at a flow rate of 0.8 mL/min, and detected at 320 nm. The HPLC method was validated according to Korea Food and Drug Administration (KFDA) guideline of analytical procedures with respect to specificity, linearity, accuracy and precision. Calibration curve of ORT showed high linearity ($R^2=1$), and limits of detection and quantification were 0.3 and $1.0{\mu}g/mL$, respectively. Relative standard deviation values from intra-and inter-day precision were less than 3.52 and 4.70%, respectively. Recovery rate ranged from 97.64% to 103.69%, and ORT content in MBE was approximately 3.78%. These results suggest that the HPLC method developed for the analysis of ORT in MBE is simple, efficient, and could contribute to the quality control of MBE.

• Journal of Food Hygiene and Safety
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• v.33 no.1
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• pp.44-49
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• 2018

As generic health functional food items have been expanded, this research project has been conducted to prepare a scientific and systematic standardized analytical method of relevant food item and examine the suitability of the method for health/functional foods on sale. Total polyphenol was necessary for development and verification of standardized analytical method. The method exhibited high linearity in the tannic acid calibration curve ($r^2$ > 0.999) over concentrations of $5-50{\mu}g/mL$. The limits of detection and quantitation for tannic acid were $5{\mu}g/mL$ and $15{\mu}g/mL$, respectively, while tannic acid recovery was 102.3-112.4% with standard deviations of 0.8-3.2%. To verify the accuracy of the analytical method, the labeled amounts of purchased health functional foods were monitored. The recovery for tannic acid was 105.6% of the labeled amounts. Thus, the new method was suitable for all cases.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.5
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• pp.274-280
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• 2020

The purpose of this study was to identify the average cost and present status of non-benefit medical expenses by using the data of tertiary hospitals released by the Health Insurance Review and Assessment Service(HIRA), and to compare the data to find cost variations. The target of analysis was the present status of the non-benefit medical expenses reported by 41 tertiary hospitals among the 44 previously designated hospitals (three were excluded due to revocation or new designation) for 2015, 2016, 2017, and 2018 (until April). This study was conducted after approval of using the released data of the HIRA's data opening system. This study was analyzed by its general characteristics, annual non-benefit medical expenses by frequency analysis, and annual understanding of variation by designating Coefficient of Variation (C.V.). The research found out that the number of details of non-benefit medical expense was gradually increased: the numbers of categories were 51 in 2015, 53 in 2016, and 98 in 2017, but there was a rapid increase in 2018 by 193. As a result, to standardize non-benefit medical expense items across tertiary hospitals due to their variations in the expenses, the government should expand standardized non-benefit medical expenses and make it mandatory for medical institutions to use the standardized items or names of such expenses.

• Analytical Science and Technology
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• v.29 no.6
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• pp.255-260
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• 2016

Based on the Korean Health Functional Food Act, health functional foods are dietary supplements containing nutrients or other substances that have nutritional or physiological effects. Since generic health functional food items have been expanded, this project was performed to develop a standardized analytical method of examining such sale items. The method exhibited high linearity in the quercetin calibration curve ($R^2$ > 0.999) over concentrations of $0-40{\mu}g/mL$. The limits of detection and quantitation for quercetin were $0.12{\mu}g/mL$ and $0.36{\mu}g/mL$, respectively, while quercetin recovery was 97.1-105.4 % with standard deviations of 1.15-3.11 %. To verify the accuracy of the analytical methods, the labeled amounts of purchased health functional foods were monitored. The recovery rate for multiple quercetin concentrations ranged from 82.5-105.1 % of the labeled amounts. Thus, the new method was suitable for all cases.

• Korean Journal of Food Science and Technology
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• v.51 no.5
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• pp.420-424
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• 2019

An HPLC analysis method was developed and standardized for the detection of dieckol as a functional food ingredient in Ecklonia cava extracts. HPLC was performed using a Capcell Pak C18 column ($250{\times}4.6mm$, $5{\mu}m$) with a gradient elution of water and acetonitrile, both containing 0.1% (v/v) trifluoroacetic acid, at a flow rate of 1.0 mL/min at $25^{\circ}C$. The eluate was detected at 230 nm. For validation, the specificity, linearity, accuracy, precision, limit of detection (LOD), and limit of quantification (LOQ) of dieckol were measured. The calibration curve for the detection of dieckol had high linearity ($R^2=0.9994$), with LOD and LOQ values of 0.38 and $1.16{\mu}g/mL$, respectively. Recovery of the quantified compound ranged from 99.61 to 100.71%. The relative standard deviation values of the intra-day and inter-day precisions were less than 1.7 and 1.25%, respectively. These results indicate that the reported HPLC method is simple, reliable, and reproducible for the detection of dieckol in Ecklonia cava extracts.