• Journal of Korean Society of Steel Construction
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• v.22 no.5
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• pp.399-409
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• 2010

Steel structures are threatened to reduce load-carrying capacity as the cross section is decreased by corrosion. However, there has been no method in definitely evaluating residual load-carrying capacity and the effect of corrosion to the load-carrying capacity of steel. This study evaluated tensile residual load-carrying capacity of corroded steel plates by using tensile tests of specimens, which were selected from the web of temporary structure's main beam. After the surface shapes were measured and tensile tests were examined, the rust of 21 corroded specimens was, first of all, removed using a chemical method. From the tensile test result, which of reference specimens that was picked off at the flange of the same main 13-mm-thick beam and corroded specimens were based, surface geometry and correlation with the reduction of corroded thickness and strain, yield strength or tensile strength was established as constant numbers. Effective thickness of corroded steel with irregular cross sections could be calculated using average residual thickness and standard deviation. The irregular cross sections could be the evaluated tensile strength that is equalized to non-corroded uniform steel's regardless of corrosion. Also, reasonable measuring intervals of residual thickness could be proposed by using this result to apply for executive work.

• Journal of Nutrition and Health
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• v.44 no.6
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• pp.577-591
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• 2011

A food exchange system for diabetes is a useful tool for meal planning and nutritional education. The first edition of the Korean food exchange lists was developed in 1988 and the second edition was revised in 1995. With recent changes in the food marketplace and eating patterns of Koreans, the third edition of food exchange lists was revised in 2010 by the Korean Diabetes Association, the Korean Nutrition Society, the Korean Society of Community Nutrition, the Korean Dietetic Association and the Korean Association of Diabetes Dietetic Educators through a joint research effort. The third edition is based on nutritional recommendations for people with diabetes and focuses on adding foods to implement personalized nutrition therapy considering individual preferences in diverse dietary environment. Foods were selected based on scientific evidence including the 2007 Korea National Health and Nutrition Examination Survey data analysis and survey responses from 53 diabetes dietetic educators. While a few foods were deleted, a number of foods were added, with 313 food items in food group lists and 339 food items in the appendix. Consistent with previous editions, the third edition of the food exchange lists included six food categories (grains, meat, vegetables, fats and oils, milk, and fruits). The milk group was subdivided into whole milk group and low fat milk. The standard nutrient content in one exchange from each food group was almost the same as the previous edition. Korea Food & Drug Administration's FANTASY (Food And Nutrient daTA SYstem) database was used to obtain nutrient values for each individual food and to determine the serving size most appropriate for matching reference nutrients values by each food group. The revised food exchange lists were subjected to a public hearing by experts. The third edition of the food exchange lists will be a helpful tool for educating people with diabetes to select the kinds and amounts of foods for glycemic control, which will eventually lead to preventing complications while maintaining the pleasure of eating.

• Journal of Soil and Groundwater Environment
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• v.17 no.6
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• pp.33-42
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• 2012

This study was performed to find the problems according to interference factors (organic matter, pH, Cr, Mn, Fe, clay, and etc.) when we analyzed the hexavalent chromium [Cr(VI)] in soils using UV/VIS spectrometer (US EPA 7196A), attempted to evaluate the domestic applicability of analytical method (US EPA 7199) using IC-UV/VIS spectrometer as alternative method. The recovery rate of certified reference materials was 75.0% (US EPA 7196A) and 101.4% (US EPA 7199) by the analytical methods. As the results of performing QA/QC about US EPA 7199, method detection limit (MDL) and limit of quantification (LOQ) were 0.062 mg/kg, 0.196 mg/kg, respectively. The LOQ of US EPA 7199 was lower than that of the current soil official testing method in Korea (0.5 mg/kg). Cr(VI) contents in 23 soil samples were compared by the analytical methods of EPA 7196A and 7199. Cr(VI) was detected in 13 of 23 soil samples by EPA 7196A, while EPA 7199 was not detected in any soil samples. The Cr(VI) content in 23 soil samples by EPA 7196A was not clearly correlated with Cr, Fe, Mn and clay content in the soil samples. However, the contents of Cr(VI) and organic matter of the soil samples had the highest coefficient of determination ($R^2$) of 0.80. In order to evaluate the correlation between the recovery rates of Cr(VI) and organic matter contents in the soil samples, the recovery rates of 5 soil samples added Cr(VI) standard solution were analyzed by the analytical methods. According to the results, the higher the organic matter contents in soil samples, the lower the recovery rates of Cr(VI) by US EPA 7196, while in case of US EPA 7199, the recovery rates were stable regardless of the organic matter contents.

• Journal of the Korean Wood Science and Technology
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• v.40 no.3
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• pp.186-193
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• 2012

The wood-concrete composite can be effectively applied for bridge superstructure, and the concept of fully composite action between each member is one of the most important consideration. Until now, related researches have been done mainly in North America and EU countries not enough to cover the fundamental studies. Therefore, this study is planned to perform one of the important issue for using the wood-concrete composite. The objective of this study is evaluation of shear performance with different anchorage length of steel rebar in wood. Prediction of the yield mode and the reference design value was firstly performed as the preliminary investigation. Then, initial stiffness, yield load and maximum load were derived from the shear test due to different anchorage length of the steel rebar (SD30A in Korean Standard) in wood. It was found out from this study that initial stiffness and yield load are not related with the anchorage length over 20 mm of anchorage length while maximum load shows increasing tendency till 60 mm of anchorage length. Pullout strength of inserted steel rebar in wood is considered to be one reason and this was also verified with the x-ray radiography.

• Journal of Positioning, Navigation, and Timing
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• v.5 no.4
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• pp.181-191
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• 2016

A Satellite Based Augmentation System (SBAS) provides differential correction and integrity information through geostationary satellite to users in order to reduce Global Navigation Satellite System (GNSS)-related errors such as ionospheric delay and tropospheric delay, and satellite orbit and clock errors and calculate a protection level of the calculated location. A SBAS is a system, which has been set as an international standard by the International Civilian Aviation Organization (ICAO) to be utilized for safe operation of aircrafts. Currently, the Wide Area Augmentation System (WAAS) in the USA, the European Geostationary Navigation Overlay Service (EGNOS) in Europe, MTSAT Satellite Augmentation System (MSAS) in Japan, and GPS-Aided Geo Augmented Navigation (GAGAN) are operated. The System for Differential Correction and Monitoring (SDCM) in Russia is now under construction and testing. All SBASs that are currently under operation including the WAAS in the USA provide correction and integrity information about the Global Positioning System (GPS) whereas the SDCM in Russia that started SBAS-related test services in Russia in recent years provides correction and integrity information about not only the GPS but also the GLONASS. Currently, LUCH-5A(PRN 140), LUCH-5B(PRN 125), and LUCH-5V(PRN 141) are assigned and used as geostationary satellites for the SDCM. Among them, PRN 140 satellite is now broadcasting SBAS test messages for SDCM test services. In particular, since messages broadcast by PRN 140 satellite are received in Korea as well, performance analysis on GPS/GLONASS Multi-Constellation SBAS using the SDCM can be possible. The present paper generated correction and integrity information about GPS and GLONASS using SDCM messages broadcast by the PRN 140 satellite, and performed analysis on GPS/GLONASS Multi-Constellation SBAS performance and APV-I availability by applying GPS and GLONASS observation data received from multiple reference stations, which were operated in the National Geographic Information Institute (NGII) for performance analysis on GPS/GLONASS Multi-Constellation SBAS according to user locations inside South Korea utilizing the above-calculated information.

• Journal of the Korean Chemical Society
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• v.55 no.3
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• pp.472-477
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• 2011

The concentration of selenium in grain samples was determined using isotope dilution method in ORC-ICPMS. The experimental conditions were optimized to $H_2$ mode and the flow rate was $4.0\;mL\;min^{-1}$. ORC in $H_2$ mode proved to eliminate most of polyatomic interferences except $BrH^+$ when Br is present in sample matrix. Chemical removal of Br was very difficult and the mathematical correction was successfully employed. The fraction of $BrH^+$ generated from Br at the current experimental condition was 14.1%. The signal on m/z 82 was corrected and calculated for isotope dilution. The analytical reliability of the propose method was successfully evaluated by analyzing the certified standard reference material NIST SRM 1566 and 1567. The method was applied to real samples and the results are $0.034{\pm}0.001\;{\mu}g\;g^{-1}$ for white rice, $0.059{\pm}0.002_5\;{\mu}g\;g^{-1}$ for brown rice, $0.029{\pm}0.001_4\;{\mu}g\;g^{-1}$ for black rice, and $0.034{\pm}0.002\;{\mu}g \;g^{-1}$ for barley. The detection limits ($3\sigma$) for Se was $0.012\;ng\;g^{-1}$.

• Journal of Korean Neurosurgical Society
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• v.61 no.2
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• pp.127-166
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• 2018

Despite advancements in treating ruptured cerebral aneurysms, an aneurysmal subarachnoid hemorrhage (aSAH) is still a grave cerebrovascular disease associated with a high rate of morbidity and mortality. Based on the literature published to date, world-wide academic and governmental committees have developed clinical practice guidelines (CPGs) to propose standards for disease management in order to achieve the best treatment outcomes for aSAHs. In 2013, the Korean Society of Cerebrovascular Surgeons issued a Korean version of the CPGs for aSAHs. The group researched all articles and major foreign CPGs published in English until December 2015 using several search engines. Based on these articles, levels of evidence and grades of recommendations were determined by our society as well as by other related Quality Control Committees from neurointervention, neurology and rehabilitation medicine. The Korean version of the CPGs for aSAHs includes risk factors, diagnosis, initial management, medical and surgical management to prevent rebleeding, management of delayed cerebral ischemia and vasospasm, treatment of hydrocephalus, treatment of medical complications and early rehabilitation. The CPGs are not the absolute standard but are the present reference as the evidence is still incomplete, each environment of clinical practice is different, and there is a high probability of variation in the current recommendations. The CPGs will be useful in the fields of clinical practice and research.

• Journal of the Korea Institute of Building Construction
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• v.18 no.2
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• pp.125-132
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• 2018

In this study, a direct tensile test was planned to identify the tensile performance of UHPC, and the irregularity of cracks, which is a problem of the direct tensile test, was complemented through the introduction of notches at the center of a specimen. In this regard, a number of specimens divided by batch to reduce the deviation of direct tensile test values were fabricated to present reference data with respect to highly reliable direct tensile strength values. In addition, the mechanical properties and reliability of the specimens were examined under the curing conditions of the specified design strength of 120MPa for the steel fiber reinforced concrete with 1.5% fiber volume fraction, which is most suitable for the field application. As a result, the deviation of averages by batch between compressive strength and direct tensile strength did not show a large difference, and all cracks occurred within 20mm in the direct tensile test. At the 95% confidence interval of the direct tensile strength, the range was considerably small in the mean and the standard deviation, and there was no significant difference depending on the curing conditions. The results confirmed that a stable direct tensile test was performed, and highly reliable results were obtained through the fabrication of specimens by batch and test progress.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.33 no.1
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• pp.31-43
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• 2015

This study had been aimed to conduct the camera calibration on VLBI antenna in the Space Geodetic Observation Center of Sejong City with a low-cost digital camera, which embedded in a mobile phone to determine the three-dimension position coordinates of the VLBI antenna, based on stereo images. The initial values for the camera calibration have been obtained by utilizing the Direct Linear Transformation algorithm and the commercial digital photogrammetry system, PhotoModeler $Scanner^{(R)}$ ver. 6.0, respectively. The accuracy of camera calibration results was compared with that the camera calibration results, acquired by a bundle adjustment with nonlinear collinearity condition equation. Although two methods showed significant differences in the initial value, the final calibration demonstrated the consistent results whichever methods had been performed for obtaining the initial value. Furthermore, those three-dimensional coordinates of feature points of the VLBI antenna were respectively calculated using the camera calibration by the two methods to be compared with the reference coordinates obtained from a total station. In fact, both methods have resulted out a same standard deviation of $X=0.004{\pm}0.010m$, $Y=0.001{\pm}0.015m$, $Z=0.009{\pm}0.017m$, that of showing a high degree of accuracy in centimeters. From the result, we can conclude that a mobile phone camera opens up the way for a variety of image processing studies, such as 3D reconstruction from images captured.

• Analytical Science and Technology
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• v.14 no.2
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• pp.131-139
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• 2001

There is personal difference in the concentrations of trace elements in human hair according to human life or history suck as occupation, race, sex, age, food habit, social condition and so on. It is also found that the individual's deviation of elemental concentrations is reflecting the degree of environmental pollutants exposure to human body, intakes of food and metabolism. To compare the degree of accumulation in the hair tissue, human hair samples were collected from five positions of head and analyzed by non-destructive neutron activation analysis with and without washing according to IAEA's recommended method. Analytical quality control is performed using the certified reference material. The relative error of Cu, Cr, Na, Co, Mg, As, Se, Zn and those of Mn, Ca, Fe, Sr are within ${\pm}5%$ and ${\pm}10%$, respectively and the relative standard deviation of elements are within ${\pm}10%$. The deviations between the individuals and hair sampling positions were estimated. The deviation of individual was seven times more than that of positions. Under the defined condition, the difference and the correlation of elemental concentrations were compared with two different groups, office and factory workers. The result can be used as a fundamental data for human health and environment assessment.