• Journal of Korean Neurosurgical Society
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• v.61 no.4
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• pp.503-508
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• 2018

Objective : Anterior odontoid screw fixation is a safe and effective method for the treatment of odontoid fractures. The surgical technique is recommended for perforation of the apical cortex of the dens by the lag screw. However, overpenetration of the apical cortex may lead to potentially serious complications such as damages of adjacent vascular and neural structures. The purpose of this study was to assess the role of three-dimensional computed tomography (CT) scan to evaluate the safe margin beyond dens tip to ventral dura for anterior odontoid screw fixation. Methods : We retrospectively analyzed the three-dimensional CT scans of the cervical spines in 55 consecutive patients at our trauma center. The patients included 38 males and 17 females aged between 22 and 73 years (mean age${\pm}$standard deviation, $45.8{\pm}14.2years$). Using sagittal images of 3-dimensional CT scan, the safe margins beyond dens tip to ventral dura as well as the appropriate screw length were measured. Results : The mean width of the apical dens tip was $9.6{\pm}1.1mm$. The mean lengths from the screw entry point to the apical dens tip and posterior end of dens tip were $39.2{\pm}2.6mm$ and $36.6{\pm}2.4mm$. The safe margin beyond apical dens tip to ventral dura was $7.7{\pm}1.7mm$. However, the safe margin beyond the posterior end of dens tip to ventral dura was decreased to $2.1{\pm}3.2mm$, which was statistically significant (p<0.01). There were no significant differences of safe margins beyond dens tip to ventral dura with patient gender and age. Conclusion : Extension by several millimeters beyond the dens tip is safe, if the trajectory of anterior odontoid screw is targeted at the apical dens tip. However, if the trajectory of the screw is targeted to the posterior end of dens tip, extension beyond dens tip may lead to damage immediately adjacent to the vental dura mater.

• Korean Journal of Human Ecology
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• v.9 no.1
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• pp.137-152
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• 2000

The purpose of this study was to investigate the disposition of adolescents in their ornament wearing pattern associate with their life style and clothing behavior. The subject of this study consists of 345 middle and high school girls living in Chung-Nam Province and Taejon Metropolitan City. SPSS/PC+ program was utilized to calculated frequency(N), mean value(M) and standard deviation(SD) for statistical analysis. Differences among the populations were examined through f test, ANOVA. The results of this study reveals that the ornaments wearing patterns are significantly different according to their life style and clothing behavior as follows: 1. Correlation between the wear of ornaments and the life style: School girls who pursue the modernistic life style prefer the fashionable ornaments (e.g. sunglasses) and they are always in contact with the latest information. On the contrary, school girls who pursue the practical life style emphasize on the practical use when they purchase the ornaments, e.g. umbrella. School girls having romantic or passive nature have a preference for the brand name and brand image of the ornaments and they in general would like to buy ornaments such as the bracelets. 2. Correlation between the wear of ornaments and the clothing behavior: School girls having sympathetic nature and being deeply interested in clothing put a stress on the latest fashion of the ornaments. They usually want to buy fashionable ornaments such as the cellular phone, beeper and sunglasses. Subjects who estimate themselves by their garments are sensitive to the price of the ornaments while aesthetes emphasize the brand image of the ornaments. Chaste school girls put their emphasis on the quality of the ornaments and they most want to have functional hair bands. Following suggestions can be made based on the discussions above: It is necessary for us to have correct understanding about the correlation between the ornaments and clothing of school girls in order to lead them to have appropriate clothing behavior. Furthermore, it is required to construct a bridge linking a course of study to rational habits guidance which will provide us more appropriate tools for clothing behavior guidance.

• Clinical and Experimental Pediatrics
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• v.51 no.6
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• pp.629-633
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• 2008

Purpose : This study was designed to investigate normal domestic values for the diameter of the left main coronary artery (LCA), the left anterior descending coronary artery (LAD) and the right coronary artery (RCA). These data are necessary to define dilatation of coronary arteries in Kawasaki disease cases. Methods : Study subjects were 43 normal healthy children whose ages ranged from 3 months to 6 years. They children visited Konkuk University hospital for echocardiograph examination between March 2005 and November 2007. Measurements of coronary arterial diameters at each branch were done by off-line analyses of recorded images. Simple regression analysis of each the measurements were performed using the body size (body surface area, etc.) as the independent variable. Results : Body surface area was significantly related to the diameters of LCA ($r^2=0.20$, P=0.0038), of LAD ($r^2=0.41$, P<0.0001), and of RCA ($r^2=0.30$, P=0.0002). In the regression model, the estimates of the y-intercept were 1.703, 1.058, and 1.007; the estimates of the regression coefficient were 0.971, 1.175, and 1.177; and the estimates of the standard deviation were 0.315, 0.221, and 0.282 with respect to the three coronary arteries. Conclusion : A the linear regression model of the diameters of three coronary arteries adjusted for body surface area was produced. With these results, the Z-score calculation of the diameter of three coronary arteries, based on normal domestic data, will be possible.

• Korean Journal of Remote Sensing
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• v.36 no.5_1
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• pp.793-806
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• 2020

In this study,for YSU (Yonsei University), MYJ(Mellor-Yamada-Janjic), ACM2 (Asymmetric Convective Model), and BouLac (Bougeault-Lacarrere) PBL schemes, numerical experiments were performed for the case period (June 26-30, 2014). The PBLH calculated by using the backscatter signal produced by the mobile vehicle-mounted lidar system (LIVE) and the PBLH calculated by the prediction of each PBL schemes of WRF were compared and analyzed. In general, the experiments using the non-local schemes showed a higher correlation than the local schemes for lidar observation. The standard deviation of the PBLH difference for daylight hours was small in the order of YSU (≈0.39 km), BouLac (≈0.45 km), ACM2 (≈0.47 km), MYJ (≈0.53 km) PBL schemes. In the RMSE comparison for the case period, the YSU PBL scheme was found to have the highest precision. The meteorological lider mounted on the vehicle is expected to provide guidance for the analysis of the planetary boundary layer in a numerical model under various weather conditions.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.42 no.8
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• pp.692-700
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• 2014

In this work, satellite FE (finite element) model updating for the prediction of the effect of micro-vibration is described. In the case of satellites launched in low earth orbit, high agility and more mission accomplishments are required by the customer in order to procure many images from satellites. To achieve the goal, many mechanisms, including high capacity wheels and antennas with multi-axis gimbals have been widely adopted, but they become a source of micro-vibration which could significantly deteriorate the quality of images. To investigate the effect due to the micro-vibration in orbit on the ground, a prediction is conducted through an integrated model coupling the measured jitter sources with FE (finite element) model. Before prediction, the FE model is updated to match simulation results with the modal survey test. Subsequently, the quality of FE model is evaluated in terms of frequency deviation error, the resemblance of mode shapes and FRFs (frequency response functions) between test and analysis.

• Environmental Analysis Health and Toxicology
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• v.29
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• pp.12.1-12.8
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• 2014

Objectives Cohort studies of associations between air pollution and health have used exposure prediction approaches to estimate individual-level concentrations. A common prediction method used in Korean cohort studies is ordinary kriging. In this study, performance of ordinary kriging models for long-term particulate matter less than or equal to $10{\mu}m$ in diameter ($PM_{10}$) concentrations in seven major Korean cities was investigated with a focus on spatial prediction ability. Methods We obtained hourly $PM_{10}$ data for 2010 at 226 urban-ambient monitoring sites in South Korea and computed annual average $PM_{10}$ concentrations at each site. Given the annual averages, we developed ordinary kriging prediction models for each of the seven major cities and for the entire country by using an exponential covariance reference model and a maximum likelihood estimation method. For model evaluation, cross-validation was performed and mean square error and R-squared ($R^2$) statistics were computed. Results Mean annual average $PM_{10}$ concentrations in the seven major cities ranged between 45.5 and $66.0{\mu}g/m^3$ (standard deviation=2.40 and $9.51{\mu}g/m^3$, respectively). Cross-validated $R^2$ values in Seoul and Busan were 0.31 and 0.23, respectively, whereas the other five cities had $R^2$ values of zero. The national model produced a higher cross-validated $R^2$ (0.36) than those for the city-specific models. Conclusions In general, the ordinary kriging models performed poorly for the seven major cities and the entire country of South Korea, but the model performance was better in the national model. To improve model performance, future studies should examine different prediction approaches that incorporate $PM_{10}$ source characteristics.

• Journal of Korean Society of Environmental Engineers
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• v.38 no.10
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• pp.558-565
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• 2016

Water quality data including flow rates and BOD/COD/T-N/T-P/SS/TOC concentrations in Nakdong river tributaries were analyzed to determine priority management areas using 699 data sets from 195 locations in 2015. It was pointed out that the coefficients of variation, the ratio of the standard deviation to the mean, for the concentrations and loading rates of BOD, T-P, and TOC in each monitoring location were so large that average values of water quality monitoring data might be not appropriate to determine the priority management areas among all 195 monitoring stations in Nakdoing river. Therefore we suggested two evaluation methods using each water quality data independently. In the first method the excess numbers of the BOD, T-P, and TOC concentrations comparing to the water quality standards in the medium-sized management areas in Nakdong river was evaluated for each monitoring station. In the second method the percentile ranks of the loading rates of the BOD, T-P, and TOC were obtained for each monitoring data. The two groups of the priority management areas determined by each method were compared and the water quality characteristics in Nakdoing river were investigated.

• Korean Journal of Psychosomatic Medicine
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• v.12 no.1
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• pp.66-75
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• 2004

Objectives: This study was intended to see the relationship between psychiatric consequences and injury severity following traffic accidents. Methods: We surveyed the 134 patients who were hospitalized from 1994 to 2003 at Chosun University Hospital for psychiatic disability evaluation following traffic accident. We reevaluate demographic factors from admission note. Psychiatric symptoms from mental status exam in medical records. Psychological tests(MMPI, BAI, BDI, K-WAIS) were done. Then we calculate the injury severity score and McBride's rate of disability due to diagnosis from emergency care hospital records. Their relationships were evaluated by statistical methods which were t-test and Pearson correlation analysis using SPSS-10. Results: When physical injury was not severe, suicidal attempt was more frequent and depression, hysteria, psychasthenia, psychopathic deviation subscales were high in MMPI. But when physical injury was severe, they have diffficulty in concentration, impaired orientation, and changed in IQ score. There was no relationship between physical injury severity and faking bad scales(F, Ds-r). Conclusion: We must not assume when physical injury was not severe, the severe sympomts are just faking for their benefit.

• Analytical Science and Technology
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• v.18 no.1
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• pp.27-34
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• 2005

$Li_2B_4O_7$ and $Na_2B_4O_7$ were synthesized with boron isotopic standard material for the measurement of boron isotopes of positive ions (PTIMS) such as $Li_2BO_2{^+}$ (mass 56, 57) and $Na_2BO_2{^+}$ (mass 88, 89) instead of boron mass 10 and 11. The negative ions (NTIMS) such as $^{10}BO_2{^-}$ and $^{11}BO_2{^-}$(mass 42와 43) were also measured with the same boron isotopic standard material. The precision and accuracy were compared between each method, and prescan of isobaric effect was studied. Good result was obtained from NTIMS method which provided the stable and enough peak intensities with good precision and accuracy. The measurement of boron isotopes were performed in ground water sample with about 8 ng-B ($5{\mu}L$ sample solution) obtained from IAEA for international inter-comparison analysis. The standard deviation was found to be 0.03%. Boron content of this ground water was measured using the NTIMS-IDMS. The result was $1.65{\pm}0.003ug-B/mL$ which was better precision compared to the ICP-AES result.

• The Journal of the Korea Contents Association
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• v.18 no.2
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• pp.468-475
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• 2018

The current system of making course evaluations mandatory in universities in Korea in order to supplement low participation levels is a major hindering factor for the validity of the evaluation results due to students' insincere responses. This study points out the problems in course evaluations that are in the form of surveys and instead proposes a sample course evaluation system that utilizes a sample mean to deduce a population mean, attempting to prove through simulation that this is statistically significant. Thus, small, medium, and large scale courses as well as cyber courses that were available in S University in the fall 2016 semester were set as the population, and each course's evaluation average grade was set as the population mean. Furthermore, we used the average grade and standard deviation of the same courses from the previous year in order to decide the sample number, the reliability level was set as 95%, and the margin of error was set as ${\pm}0.25$. As a result of carrying out a simulation using the data analysis tool R, all the courses (small scale, medium scale, large scale, and cyber) showed to have a reliability level close to 95% including the population mean, and consequently practicality of the representative sample course evaluation system was proven.