• The Journal of Korean Society for Radiation Therapy
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• v.23 no.1
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• pp.51-58
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• 2011

Purpose: In this study, we tried to check the usefulness of two Linear Accelerators, Clinac IX and 21EX (Varian, Palo Alto, CA), which are equipped in Ajou Medical Center. From 2008 to 2010, we evaluated the error range of Absolute Dose based on the daily output, which was measured by CHECKMATE$^{TM}$ (Sun Nuclear, Melbourne, FL). Materials and Methods: For Daily Q.A, photon beams of two linear accelerators, 21EX and IX (6 MV and 10 MV, respectively) were measured daily by using CHECKMATE$^{TM}$ just before the treatment began, while the absolute dose was measured biweekly by using water phantom. We analyzed the data of measured values from the daily Q.A and the absolute dose from 2008 to 2010 for 21EX, and from 2009 to 2010 for IX. We utilized Excel 2007 (Microsoft, USA) to evaluate Average, Standard deviation and Confidence level of the data. Furthermore, in order to check the measured values of CHECKMATE$^{TM}$ and the significance of absolute dose, each error value was compared and analyzed. Results: During the observation period, the output of two equipment's absolute dose increased in process of time and in both 6 MV and 10 MV, there was a similar increasing trend. In addition, the error rate of the measured value of CHECKMATE$^{TM}$ and the value of absolute dose were under 0.34, which means that there is a similarity relationship between the two measured values. After checking that the measured value of CHECKMATE$^{TM}$ increased, We measured the absolute dose to adjust that. When the error range was close to 2~3%, the number of changing the output was four for 21EX and three for IX. Conclusion: As a result of measuring and analyzing the daily output changes for two years by using CHECKMATE$^{TM}$, we could find that there is a significance between the output which we should obey during Q.A, and the measured value of absolute dose within the error tolerance of 2~3%. Thus, the use of CHECKMATE$^{TM}$ can be positively considered for more efficient and reliable daily output verification of linear accelerator. It can also be a good standard for other medical centers to understand the trends of linear accelerator and to refer to for the correction of each output.

• The Korean Journal of Nuclear Medicine Technology
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• v.14 no.2
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• pp.3-8
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• 2010

Purpose: $^{11}C$-Acetate PET/CT is useful in detecting lesions that are related to livers in the human body and leads to a sensitivity of 87.3%. On the other hand, $^{18}F$-FDG PET/CT has a sensitivity of 47.3% and it has been reported that if both $^{18}F$-FDG and $^{11}C$-Acetate PET/CT are carried out together, their cumulative sensitivity is around 100%. However, the normal intake of the pancreas and the spleen in $^{11}C$-Acetate PET/CT can influence the $^{18}F$-FDG PET/CT leading to an inaccurate diagnosis. This research was aimed at the verification of the usefulness of how much influence these two radioactive medical supplies can cause on the medical images through comparative analysis between the one-day and two-day protocol. Materials and Methods: This research was carried out based on 46 patients who were diagnosed with liver cancer and have gone through the PET/CT (35 male, 11 female participants, average age: $54{\pm}10.6$ years, age range: 29-69 years). The equipment used for this test was the Biograph TruePoint40 PET/CT (Siemens Medical Systems, USA) and 21 participants who went through the one-day protocol test were first given the $^{11}C$-Acetate PET/CT and the $^{18}F$-FDG PET/CT, the latter exactly after one hour. The other 25 participants who went through the two-day protocol test were given the $^{11}C$-Acetate PET/CT on the first day and the $^{18}F$-FDG PET/CT on the next day. These two groups were then graded comparatively by assigning identical areas of interest of the pancreas and the spleen in the $^{18}F$-FDG images and by measuring the Standard Uptake Value (SUV). SPSS Ver.17 (SPSS Inc., USA) was used for statistical analysis, where statistical significance was found through the unpaired t-test. Results: After analyzing the participants' medical images from each of the two different protocol types, the average${\pm}$standard deviation of the SUV of the pancreas carried out under the two-day protocol were as follows: head $1.62{\pm}0.32$ g/mL, body $1.57{\pm}0.37$ g/mL, tail $1.49{\pm}0.33$ g/mL and the spleen $1.53{\pm}0.28$ g/mL. Whereas, the results for participants carried out under the one-day protocol were as follows: head $1.65{\pm}0.35$ g/mL, body $1.58{\pm}0.27$ g/mL, tail $1.49{\pm}0.28$ g/mL and the spleen $1.66{\pm}0.29$ g/mL. Conclusion: It was found that no statistical significant difference existed between the one-day and two-day protocol SUV in the pancreas and the spleen (p<0.05), and nothing which could be misconceived as false positive were found from the PET/CT medical image analysis. From this research, it was also found that no overestimation of the SUV occurred from the influence of $^{11}C$-Acetate on the $^{18}F$-FDG medical images where those two tests were carried out for one day. This result was supported by the statistical significance of the SUV of measurement. If $^{11}C$-Acetate becomes commercialized in the future, the diagnostic ability of liver diseases can be improved by $^{18}F$-FDG and one-day protocol. It is from this result where tests can be accomplished in one day without the interference phenomenon of the two radioactive medical supplies and furthermore, could reduce the waiting time improving customer satisfaction.

• Journal of Intelligence and Information Systems
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• v.23 no.1
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• pp.23-46
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• 2017

Although there have been cases of evaluating the value of specific companies or projects which have centralized on developed countries in North America and Europe from the early 2000s, the system and methodology for estimating the economic value of individual technologies or patents has been activated on and on. Of course, there exist several online systems that qualitatively evaluate the technology's grade or the patent rating of the technology to be evaluated, as in 'KTRS' of the KIBO and 'SMART 3.1' of the Korea Invention Promotion Association. However, a web-based technology valuation system, referred to as 'STAR-Value system' that calculates the quantitative values of the subject technology for various purposes such as business feasibility analysis, investment attraction, tax/litigation, etc., has been officially opened and recently spreading. In this study, we introduce the type of methodology and evaluation model, reference information supporting these theories, and how database associated are utilized, focusing various modules and frameworks embedded in STAR-Value system. In particular, there are six valuation methods, including the discounted cash flow method (DCF), which is a representative one based on the income approach that anticipates future economic income to be valued at present, and the relief-from-royalty method, which calculates the present value of royalties' where we consider the contribution of the subject technology towards the business value created as the royalty rate. We look at how models and related support information (technology life, corporate (business) financial information, discount rate, industrial technology factors, etc.) can be used and linked in a intelligent manner. Based on the classification of information such as International Patent Classification (IPC) or Korea Standard Industry Classification (KSIC) for technology to be evaluated, the STAR-Value system automatically returns meta data such as technology cycle time (TCT), sales growth rate and profitability data of similar company or industry sector, weighted average cost of capital (WACC), indices of industrial technology factors, etc., and apply adjustment factors to them, so that the result of technology value calculation has high reliability and objectivity. Furthermore, if the information on the potential market size of the target technology and the market share of the commercialization subject refers to data-driven information, or if the estimated value range of similar technologies by industry sector is provided from the evaluation cases which are already completed and accumulated in database, the STAR-Value is anticipated that it will enable to present highly accurate value range in real time by intelligently linking various support modules. Including the explanation of the various valuation models and relevant primary variables as presented in this paper, the STAR-Value system intends to utilize more systematically and in a data-driven way by supporting the optimal model selection guideline module, intelligent technology value range reasoning module, and similar company selection based market share prediction module, etc. In addition, the research on the development and intelligence of the web-based STAR-Value system is significant in that it widely spread the web-based system that can be used in the validation and application to practices of the theoretical feasibility of the technology valuation field, and it is expected that it could be utilized in various fields of technology commercialization.

• Journal of Korean Home Economics Education Association
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• v.18 no.1 s.39
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• pp.31-47
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• 2006

This study developed practical reasoning teaching-learning material for middle school home economics education and tested its effects on middle school students' self-esteem The type of this study was a quasi-experimental research and its independent variable was practical reasoning instruction and its dependent variable was self-esteem. The research design for this study was a pretest-posttest design. Practical reasoning instruction was given for experimental group whereas traditional instruction was given to comparison group. For measuring self-esteem, 'self-esteem scale' developed by Choi & Jun(1993) was used and its Cronbach'a was ranged from .69 to .84. Statistic analysis was done by mean and standard deviation for general characteristics of samples and paired t-test for testing difference of pretest-posttest. The results of this study showed that practical reasoning instruction improved middles school students' self-esteem, the general self-esteem and social self-esteem among sub-areas of self-esteem in particular.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.3
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• pp.360-369
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• 2012

Parent material, climate, topography, biological factors, and time are considered five soil forming factors. This study was conducted to elucidate the effects of several environment factors on soil distribution using quantitative analysis method, called soil series estimation algorithm in the soils of Jeju Island. We selected environment factors including mean temperature, annual precipitation, surface geology, altitude, slope, aspect, altitude difference within 1 $km^2$ area, topographic wetness index, distance from the shore, distance from the mountain peak, and landuse for a quantitative analysis. We analyzed the ranges of environment factors for each soil series and calculated probabilities of possible-soil series for certain locations using estimation algorithm. The algorithm can predicted exact soil series on the soil map with correctness of 33% on $1^{st}$ ranking, 62% within $2^{nd}$ ranking, 74% within $5^{th}$ ranking after estimating using randomly extracted environment factors. In predicted soil map, soil sequences of Entisols-Alfisols-Andisols on northern area and Alfisols-Ultisols-Andisols on western area can be suggested along increasing altitude. More modeling studies will be needed for the genesis process of soils in Jeju Island.

• Journal of the Earthquake Engineering Society of Korea
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• v.13 no.6
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• pp.27-37
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• 2009

A method of instrumentally estimating seismic intensity (MMI) based on the Fourier Acceleration Spectrum of earthquake ground-motion, the so-called 'FAS MMI method' of Sokolov and Wald (2002), was evaluated for its applicability to Korea based on the empirical models of mean (m) and standard deviation (${\sigma}$) for Korea according to individual seismic intensity for MMI ${\leq}$ IV (Yun et al., 2009). This evaluation showed that the error in estimating the seismic intensity using the FAS MMI method is ${\sigma}$ = 0.74 MMI, and was further reduced to ${\sigma}$ = 0.61 MMI if the dependency of the error on earthquake magnitude and distance is additionally corrected. It is also shown that FAS MMI based on the FAS semi-empirically evaluated from small earthquakes for damaging earthquakes in Korea with maximum MMI ${\geq}$ VI could predict the observed MMI with the maximum error of 0.63 by using the combined FAS m-${\sigma}$ models of Korea for MMI ${\leq}$ IV and global region for MMI ${\geq}$ V.

• Journal of Food Hygiene and Safety
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• v.34 no.6
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• pp.519-525
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• 2019

The Ministry of Food and Drug Safety (MFDS) is amending its test methods for health functional foods (dietary food supplements) to establish regulatory standards and specifications in Korea. In this regard, we are continuing our research on analytical method development for the items listed in the Korean Health Functional Food Codex. In this study, we have developed a sensitive and selective test method that could simultaneously separate and determine coenzyme Q10 based on liquid chromatographic-tandem mass spectrometry (LC-MS/MS). Calibration curves showed linearity with a correlation coefficient (R²) of > 0.999 and the limits of detection (LODs) and limits of quantitation (LOQs) were in the range of 26.0 ㎍/L and 78.9 ㎍/L, respectively. The recovery results ranged between 98.6-107.0% at 3 different concentration levels with relative standard deviations (RSDs) less than 5%. The proposed analytical method was characterized with high resolution of the coenzyme Q10 and the assay was fully validated as well.

• The Journal of Engineering Geology
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• v.26 no.1
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• pp.71-78
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• 2016

This study aimed to evaluate the occurrence of natural radionuclides in Korean groundwater. Groundwater radionuclide data for the period 2000-2011 were obtained from the National Institute of Environmental Research and published literature, classified into five groups according to host rock type, and used to construct detailed concentration maps. Radon, uranium, gross-α, and radium concentrations ranged from 0.4 to 64,688.0 pCi/L (mean: 4,907 pCi/L), 0 to 2,297 μg/L (mean: 27.5 μg/L), 0 to 312 pCi/L (mean: 3.9 pCi/L), and 0 to 17.4 pCi/L (mean: 0.2 pCi/L), respectively. Radon concentrations in 562 of a total 1,501 wells (i.e., 53.5%) exceeded 4,000 pCi/L, which is the acceptable contamination threshold established by the United States Environmental Protection Agency. Uranium, gross-α, and radium concentrations exceeded the respective thresholds of 30 μg/L, 15 pCi/L, and 5 pCi/L in 121 of 1,031 wells (11.9%), 34 of 978 wells (3.5%), and 4 of 89 wells (4.5%), respectively. The mean radionuclide concentration in groundwaters hosted by igneous and metamorphic rocks was higher than that in groundwaters hosted by other rock types, such as volcanics, carbonates, and other sedimentary rocks. The correlations between individual radionuclides were weak or insignificant.

• 한국신재생에너지학회:학술대회논문집
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• 2005.06a
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• pp.586-591
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• 2005

우리나라는 에너지의 안정적 공급과 에너지이용 과정에서 발생하는 환경적, 안보적 외부성을 최소화하는 에너지수급 구조를 마련하기 위해 2003년 12월 '제2차 신재생에너지 기술개발 및 이용보급 기본계획(2003-2012)'을 발표하였다. 이 계획에서는 2011년까지 전체 TPES의 $5\%$를 신재생에너지로 공급하는 것을 정책목표로 수립하고 수소, 태양광 그리고 풍력기술을 중점적으로 추진하기로 하였다. 특히 수소부문에서는 주택 및 건물용, 발전용, 수송용 연료전지의 개발을 중심으로 개발하여 세계 기술시장의 $20\%$를 확보한다는 계획을 발표하였다. 이러한 기술 잠재력을 기반으로 우리 정부도 미국이나 일본과 같이 수소경제로의 전환을 준비하고 있으며 2020년대 이후 우리나라의 에너지부문은 새로운 국면에 접어들 것으로 전망된다. 에너지나 환경기술의 효과적 인 개발을 위해서는 이들 기술의 직접적인 비용측면에 대한 분석 즉 경제성 평가와 새로운 기술변화로 인한 중장기적인 사회경제적 영향평가가 선행되어야 한다. 이러한 평가는 대상 기술의 사회경제적 파급효과가 광범위할수록 더욱 복잡한 분석이 요구된다. 본 연구의 주제인 수소에너지기술은 지금까지 이용되던 것과는 전혀 새로운 에너지캐리어(carrier)를 개발하는 것으로 에너지부문 및 여타 다른 산업부문이 공유하고 있는 에너지 관련 인프라의 전면적인 조정이 요구되며 에너지 이용과 관련된 사회경제적 측면의 급속한 변화를 수반한다. 본 연구는 수소경제로의 이행에 대한 사회경제적 영향평가의 방법론적 요소들과 기법을 제시한다."중등도 독성"으로 나타났다 이상의 결과는 전기도금을 이용하여 교정용 선재의 직경을 증가시키는 방법이 임상에 적용되기 위해서는 세포독성을 줄이기 위한 추가의 연구가 필요함을 시사하였다.의하게 가장 낮은 정지. 운동 마찰력을 보였고 브라켓-호선 각도가 증가함에 따라 유의하게 정지, 운동 마찰력도 증가하였다 (P<0.001)%$ 낮추지만(p value=0.260) 평균 $D_{max}$는 거의동일 하여($0.3\%$ 감소, p value=0.867), 전통적인 방법보다 우수성이 크게는 없는 것으로 평가되었다. 그러나 환자의 체곡선이 보상체와 잘 일치하는 경우에는 DII가 $18\%$까지 감소하였다. 결론 : Multistatic field 방법은 모든 환자에 대하여 선량분포의 균일성을 전반적으로 향상시키는 효과적인 방법으로 평가되는 반면 공용보상체의 사용은 보상체의 크기가 환자의 체 윤곽과 잘 일치하는 경우만 효과적으로, 적용의 범위에는 한계가 있는 방법으로 평가되었다.비교하여 계통에 따르는 차이가 있음을 알 수 있었다. 그러므로 가임기 여성의 방사선 진단 및 치료시 Rugh의 10일 법칙을 적용하여 착상전기 방사선 조사로 인한 부작용들을 적극적으로 예방하는 것이 매우 중요하다고 생각한다.equirements of the prematured infants during the early weeks of life. 모든 치근단 수준에서 비표준화 medium 크기 master cone 사용군이 ISO 표준화 규격의 master cone 사용군에 비해

• Tunnel and Underground Space
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• v.19 no.3
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• pp.203-212
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• 2009

The prediction of near field behavior around an underground high-level radioactive waste repository is important for the repository design as well as the safety assessment. In this study, a sensitivity analysis for seven parameters consisted of design parameters and material properties was carried out using a three-dimensional finite difference code. From the sensitivity analysis, it was found that the effects of borehole spacing, tunnel spacing, cooling time and rock thermal conductivity were more significant than the other parameters. For getting a statistical distribution of buffer and rock temperatures around the repository, an artificial neural network, backpropagation, was applied. The reliability of the trained neural network was tested with the cases with randomly chosen input parameters. When the parameter variation is within ${\pm}10%$, the prediction from the network was found to be reliable with about a 1% error. It was possible to calculate the temperature distribution for many cases quickly with the trained neural network. The buffer and rock temperatures showed a normal distribution with means of $98^{\circ}C$ and $83.9^{\circ}C$ standard deviations of $3.82^{\circ}C$ and $3.67^{\circ}C$, respectively. Using the neural network, it was also possible to estimate the required change in design parameters for reducing the buffer and rock temperatures for $1^{\circ}C$.