• Journal of the Korean Society of Food Science and Nutrition
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• v.41 no.12
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• pp.1753-1757
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• 2012

A new liquid chromatographic tandem mass spectrometric (LC-MS/MS) assay for the quantification of ginsenoside Rb1 in human plasma was developed and validated. The separation was performed on a Agilent C18 column ($4.6mm{\times}150mm$, particle size 5 ${\mu}m$) with a gradient elution of 0.1% formic acid in water and 0.1% formic acid in methanol and a flow rate of 0.9 mL/min. The analyte was determined using electrospray positive ionization mass spectrometry in the multiple reaction monitoring (MRM) mode (m/z 1131.714${\rightarrow}$365.303). Human plasma samples were extracted with acetone : water (50:50) by the liquid-liquid extraction method. The method was linear over the dynamic range of 10~500 ng/mL with a correlation coefficient of r=0.9995. The intra-and inter-day precision over the concentration range of ginsenoside Rb1 was lower than 5.8% (correlation of variance, CV), and the accuracy was between 96.0~104.6%. This LC-MS/MS assay of ginsenoside Rb1 in human plasma is applicable for quantification in a pharmacokinetic study.

• Journal of Pharmaceutical Investigation
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• v.38 no.2
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• pp.135-142
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• 2008

The present study describes the evaluation of the bioequivalence of two atorvastatin tablets, Lipitor $Tablet^{(R)}$ (Pfizer, reference drug) and Atorva $Tablet^{(R)}$ (Yuhan, test drug), according to the guidelines of Korea Food and Drug Administration (KFDA). Forty-nine healthy male Korean volunteers received each medicine at the atorvastatin dose of 40 mg in a $2{\times}2$ crossover study with a two weeks washout interval. After drug administration, serial blood samples were collected at a specific time interval from 0-48 hours. The plasma atorvastatin concentrations were monitored by an high performance liquid chromatography -tandem mass spectrometer (LC-MS/MS) employing electrospray ionization technique and operating in multiple reaction monitoring (MRM) and positive ion mode. The total chromatographic run time was 4.5 min and calibration curves were linear over the concentration range of 0.1-100 ng/mL for atorvastatin. The method was validated for selectivity, sensitivity, linearity, accuracy and precision. $AUC_t$ (the area under the plasma concentration-time curve from time zero to 48hr) was calculated by the linear log trapezoidal rule method. $C_{max}$ (maximum plasma drug concentration) and $T_{max}$ (time to reach $C_{max}$) were complied trom the plasma concentration-time data. Analysis of variance was carried out using logarithmically transformed $AUC_t$ and $C_{max}$. No significant sequence effect was found for all of the bioavailability parameters indicating that the crossover design was properly performed. The 90% confidence intervals of the $AUC_t$ ratio and the $C_{max}$ ratio for Atorva $Tablet^{(R)}$ / Lipitor $Tablet^{(R)}$ were ${\log}\;0.9413{\sim}{\log}\;1.0179$ and ${\log}\;0.831{\sim}{\log}\;1.0569$, respectively. These values were within the acceptable bioequivalence intervals of ${\log}\;0.8{\sim}{\log}\;1.25$. Based on these statistical considerations, it was concluded that the test drug, Atorva $Tablet^{(R)}$ was bioequivalent to the reference drug, Lipitor $Tablet^{(R)}$.

• The Journal of Engineering Geology
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• v.25 no.4
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• pp.587-598
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• 2015

We examined various existing threshold methods for the determination of the first arrival time of acoustic emission (AE), and developed a new variable threshold method that could determine the first arrival time of AE more accurately and more quickly than existing methods. The new method, a modification of an existing threshold method, does not fix the threshold, but applies variable thresholds for the AE signals according to noise analysis. Two- and three-dimensional models were established to test the effectiveness of the new method. It could determine source locations of AE in a two-dimensional model 38.3% more accurately than the pre-existing threshold methods. Its accuracy improvement over the existing methods in a three-dimensional model was about 15.2%. A practical test involved measuring the source locations of AE during three-point bending tests of granite cores. The new method placed the sources closer to the fracture plane than did the pre-existing methods, indicating its superior (and quicker) ability to determine the source locations of AE.

• The Journal of Engineering Geology
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• v.24 no.1
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• pp.53-67
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• 2014

Numerical modeling is commonly used to reproduce the physical phenomena of dam-break and to compile resulting flood hazard maps. The accuracy of a dam-break model depends on the physical structure that describes the volume of storage, breach formation and progress, input variables, and model parameters. Model input and parameters are subjective in that they are prescribed; hence, caution is needed when interpreting the results. This study focuses on three parameters (breach degree ${\theta}$, shape factor P, and collapse rate k) used when the dam-break model is coupled with FLO-2D (a two-dimensional flood simulation model) to estimate flood coverage and depth etc. The results show that the simulation is sensitive to the shape factor P and the collapse rate k but not to the breach degree ${\theta}$. This study will contribute to reducing flood damage from dam-break disasters in the future.

• Science of Emotion and Sensibility
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• v.20 no.4
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• pp.41-54
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• 2017

Physical activity has positive effects on cognitive functions by aging. However, it is rare to find research that have scientifically investigated the effects on the affective-cognitive function. Thus, this study aims to brain-scientifically research its effects of physical activity on the affective-cognitive function of adults in adolescence and senescence. As subjects of this study, a total of 60 males adults in D region were selected, and then equally divided into four groups of young exercise group(25~35y/o), young non-exercise group(26~35y/o), old exercise group(60~70y/o), and old non-exercise group(60~70y/o). As experiment tools, the EEG measuring equipment and International Affective Picture System(IAPS) were used. The experiment of this study used an affective-cognitive task where subjects pressed a button depending on emotional valence(positive, neutral, negative) shown in the pictures. During the task, EEG measured eight areas(Fp1, Fp2, Fz, C3, C4, Cz, T3, T4) out of brain areas in accordance with the international 10-20 electrode system, EEG was measured. For statistical analysis, a three-way ANOVA on $4(group){\times}3(stimulus){\times}8(area)$ was conducted. The results showed main effects of group in both reaction time and accuracy, and also in the latency of P3. And there was an interaction between group and stimulus the amplitude of P3. In conclusion, Physical activity has positive effects on the affective-cognitive function of people in adolescence and senescence.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.16 no.1
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• pp.39-46
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• 2004

In the GIS construction to land and sea in Korea, GIS construction on land was completed mostly for big cities by NGIS(National Geography Information System) business. However, Marine GIS being constructed by the National Oceanographic Research Institute is still constructing geography information and definition of attribute information and real condition. We have done researches to get maximized ripple effect linking GPS and Navigation techniques on GIS. GPS in accuracy is divided into navigation and precise surveying equipments. Now, GPS technology has been developed very much and with low price GPS equipments are being introduced. But costs on the GPS equipments are high yet. Therefore, the GPS equipments for navigation can be substituted by cheap GPS equipments in a car or ship. In this paper, the authors developed algorithm to convert ellipsoid coordinate between WGS84 and Bessel ellipsoid and to analyze map projection between BESSEL ellipsoid and UTM plane coordinate system. And the author developed ship navigation system with cheap GPS equipments using algorithm of ellipsoid conversion and map projection. The authors proposed the necessity on constructing Internet GIS to manage many ships.

• Archives of design research
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• v.17 no.1
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• pp.383-392
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• 2004

The power tools is the product using working power generated by electric motor. Many companies are manufacturing numerous devices. Main features of tools are included various assembled products, small, light and solid and durable enough to match several standards. Fundamental requirements for the product is excellent performance and convenience for use. The quality of them depends on the equipped motor'(s) capability, accuracy of gear and endurance against worn-out. By adapting the state-of-the-art parts, they could be used in the place from home to heavy industry broadly. They can be classified electronic drills, grinders, saws and sanders families for the household appliances. For industrial tools, bore drill, grinder, polisher, and driver drill are classified as special and high priced group. This study presents the strategy of power tool development of BOSCH, BLACK&DECKER and KEYANG. Their products were analyzed in terms of product line and product mix concept. Then they are examined by design elements, such as color, shape and material for housing. As an analysis method, the image scale parameter and criteria were applied to each company's product.

• Analytical Science and Technology
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• v.29 no.4
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• pp.202-208
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• 2016

본 연구에서는 사료 첨가제로 이용되고 있는 유기산 7종(formic acid, malic acid, lactic acid, acetic acid, citric acid, fumaric acid, propionic acid)의 동시분석법 개발을 위한 연구를 실시하였다. 7종의 화합물은 표준물질의 Retention time과 UV spectra를 통해 구별하였고, 분석법 검증은 직선성, 민감성, 선택성, 정확성, 정밀성을 통하여 검증하였다. 그 결과로 LOD와 LOQ의 범위가 각각 43~26,755 μg/kg, 12-8,026 μg/kg으로 설정하였고, 평균 회수율이 79.3~95.2%로 우수하게 보였으며, intra-day, inter-day에 대한 전반적인 상대 표준 편차(%RSD)는 3.2% 미만으로 나타났다. 이와 같이 검증된 자료를 통해 유기산의 동시분석에 대한 직선성, 민감성, 선택성, 정확성 및 정밀성을 확인하였고, 높은 수준을 나타냄을 알 수 있었다. 이를 바탕으로 유기산이 검출되는 단미사료 46 가지를 분석에 적용하여 진행하였고, 정량과 동시분석 검출을 위한 방법은 RP-HPLC/UV 검출기를 이용하여 성공적으로 개발되었다. 따라서 본 연구결과를 바탕으로 하여 사료 중의 유기산의 분석이 신속하고 정확해졌을 뿐 아니라, 다른 종류의 사료 또한 이를 적용하여 효율적으로 이용할 수 있을 것으로 판단된다.

• Analytical Science and Technology
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• v.25 no.2
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• pp.152-157
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• 2012

Currently, many types of compound preparations are being used but the quality control guidelines for their use are lacking. In case of single compound drug, the quality control methods are specified in the pharmacopeia. However, there is no method to simultaneously analyze compound preparations. In this study, a simple validated analytical method for HPLC separation of chlorquinaldol and promestriene is introduced. Validation was divided into categories including linearity, precision, accuracy (recovery) and system suitability. The contents of the products which are on the market were monitored using the validated analytical method and the robustness of the analytical method was tested by conducting an inter-laboratory validation.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.10 no.6
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• pp.609-616
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• 2017

In this paper, we propose an algorithm to obtain more stable and high recognition rate by using left and right rotation information of input image in order to obtain a stable recognition rate in face recognition. The proposed algorithm uses the facial image as the input information in the web camera environment to reduce the size of the image and normalize the information about the brightness and color to obtain the improved recognition rate. We apply Principal Component Analysis (PCA) to the detected candidate regions to obtain feature vectors and classify faces. Also, In order to reduce the error rate range of the recognition rate, a set of data with the left and right $45^{\circ}$ rotation information is constructed considering the directionality of the input face image, and each feature vector is obtained with PCA. In order to obtain a stable recognition rate with the obtained feature vector, it is after scattered in the eigenspace and the final face is recognized by comparing euclidean distant distances to each feature. The PCA-based feature vector is low-dimensional data, but there is no problem in expressing the face, and the recognition speed can be fast because of the small amount of calculation. The method proposed in this paper can improve the safety and accuracy of recognition and recognition rate faster than other algorithms, and can be used for real-time recognition system.