• Journal of the Computational Structural Engineering Institute of Korea
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• v.33 no.3
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• pp.179-186
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• 2020

In this study, the wall stress and rupture risk for abdominal aortic aneurysms were calculated based on the age and geometry of the examined abdominal aortic aneurysms. The geometry of the abdominal aorta was simulated using computed tomography data from patients with abdominal aortic aneurysms. With regard to material properties, the Gasser-Ogden-Holzapfel model was applied to the analysis to simulate the anisotropic hyperelastic characteristics of the artery. In addition, each material parameter was estimated to consider the properties for age and for normal and aneurysm tissue. Moreover, the correlation between the diameter and angle of the aortic aneurysms was analyzed based on data from patients with abdominal aortic aneurysms, and series simulations were conducted. As a result, the rupture risk for the abdominal aortic aneurysms was evaluated based on the age and geometry of the aneurysm.

• Korean Journal of Head & Neck Oncology
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• v.18 no.1
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• pp.50-55
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• 2002

Objectives: Thyroid cancer is the most common endocrine malignancy with favorable histologic and prognostic characteristics. Total or near total thyroidectomy has been used as a standard surgical procedure. The aims of this study are to determine the extent of resection of thyroid gland and to find the influencing factors of lymph node metastasis. Materials and Methods: The authors reviewed the records of 194 patients of thyroid cancer surgically treated at Department of General Surgery, Inje University Busan Paik Hospital from January, 1996 to December, 2000. Pathologic classifications, surgical procedures, and lymph node metastasis were analyzed. Results: There were 163 women and 31 men. The age ranged from 12 to 79 years old (mean age 43.2 years). The histological classifications of 194 cases revealed papillary cancer in 171 cases (88.1%), follicular cancer in 17 cases (8.8%), undifferentiated cancer in 3 cases (1.6%), medullary cancer in 2 cases (1.0%) and mixed cancer in 1 case (0.5%). Among the 194 patients, lobectomy was perfomed in 31 patients, subtotal thyroidectomy in 30 patients, near total thyroidectomy in 82 patients and total thyroidectomy in 51 patients. In the subgroup of papillary carcinoma 141 cases with lymph node dissection, lymph node metastasis had no statistical significance according to sex, age and primary tumor size. Conclusions: The mainly performed surgical procedures were total thyroidectomy and near total thyroidectomy. In thyroid cancer surgery, the extent of resection was influenced by age, differentiation and primary tumor size. The lymph node dissection should be decided by lymph node metastasis identified by preoperative radiologic evaluation or intraoperative lymph node findings.

• Korean Journal of Veterinary Research
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• v.51 no.3
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• pp.227-231
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• 2011

This study was undertaken to assess the lateral ventricle, which was some portion of brain and related to congenital anomalies, from 1, 2, 4, and 8 months of age in healthy micropigs. They were induced general anesthesia and performed magnetic resonance imaging (MRI) with a 0.3 Tesla magnet. Each age group was evaluated by three subjects such as lateral ventricular volume, ventricular volume ratio and asymmetry. T1 weighted transverse images were acquired for calculation of lateral ventricular and corresponding brain parenchyma areas. The ratio of bilateral ventricle areas used to analyze the asymmetry. The mean ventricular volumes of each month were $676.74{\pm}25.58mm^3$ (1 month-old), $630.64{\pm}143.84mm^3$ (2 month-old), $992.12{\pm}106.03mm^3$ (4 month-old) and $1172.62{\pm}237.57mm^3$ (8 month-old), respectively. The ventricular volume ratio was the smallest at 2 month-old and re-increased from that age. The ratio was significantly different between 2 month-old and other age groups (p < 0.05). The value of bilateral area ratio showed within 1.5 in all experimental animals. Consequently the lateral ventricle showed a positive correlation with aging and symmetric shapes in both sides. The developmental pattern of the lateral ventricle provides basic data in micropigs as an experimental animal model for physiological and neurosurgical approach.

• Journal of Korean Neurosurgical Society
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• v.51 no.1
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• pp.24-30
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• 2012

Objective : This study was conducted to assess the clinical significance of traumatic brain stem injury (TBSI) reflected on Glasgow Coma Score (GCS) and Glasgow Outcome Score (GOS) by various clinical variables. Methods : A total of 136 TBSI patients were selected out of 2695 head-injured patients. All initial computerized tomography and/or magnetic resonance imaging studies were retrospectively analyzed according to demographic- and injury variables which result in GCS and GOS. Results : In univariate analysis, mode of injury showed a significant effect on combined injury (p<0.001), as were the cases with skull fracture on radiologic finding (p<0.000). The GCS showed a various correlation with radiologic finding (p<0.000), mode of injury (p<0.002), but less favorably with impact site (p<0.052), age (p<0.054) and skull fracture (p<0.057), in order of statistical significances. However, only GOS showed a definite correlation to radiologic finding (p<0.000). In multivariate analysis, the individual variables to enhance an unfavorable effect on GCS were radiologic finding [odds ratio (OR) 7.327, 95% confidence interval (CI)], mode of injury (OR; 4.499, 95% CI) and age (OR; 3.141, 95% CI). Those which influence an unfavorable effect on GOS were radiologic finding (OR; 25.420, 95% CI) and age (OR; 2.674, 95% CI). Conclusion : In evaluation of TBSI on outcome, the variables such as radiological finding, mode of injury, and age were revealed as three important ones to have an unfavorable effect on early stage outcome expressed as GCS. However, mode of injury was shown not to have an unfavorable effect on late stage outcome as GOS. Among all unfavorable variables, radiological finding was confirmed as the only powerful prognostic variable both on GCS and GOS.

• Journal of the Korean Recycled Construction Resources Institute
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• v.7 no.2
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• pp.93-100
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• 2019

In this study, the mechanical properties of early-age concrete were evaluated by mixing the electric arc furnace oxidizing slag fine aggregate with 30% and 50% replacement ratio. Slump test, air content test and unit volume weight test were performed for fresh concrete, and compressive strength test and chloride penetration experiments were carried out in hardened concrete. The compressive strength increased up to 7 days of curing age with increasing replacement ratio of the electric furnace oxidizing slag, but the strength decreased to 90% level of OPC concrete at 28 days of age. Regarding the result of chloride penetration test, no significant differences from OPC concrete were evaluated, which shows a feasibility of application to concrete aggregate.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.4
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• pp.2533-2540
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• 2013

Background: Although screening is necessary where gastric cancer is particularly common in Asia, the performance outcomes of mass screening programs have remained unclear. This study was conducted to evaluate cost-effectiveness outcomes of the national cancer screening program (NCSP) for gastric cancer in South Korea. Materials and Methods: People aged 40 years or over during 2002-2003 (baseline) were the target population. Screening recipients and patients diagnosed with gastric cancers were identified using the NCSP and Korea Central Cancer Registry databases. Clinical outcomes were measured in terms of mortality and life-years saved (LYS) of gastric cancer patients during 7 years based on merged data from the Korean National Health Insurance Corporation and National Statistical Office. We considered direct, indirect, and productivity-loss costs associated with screening attendance. Incremental cost-effectiveness ratio (ICER) estimates were produced according to screening method, sex, and age group compared to non-screening. Results: The age-adjusted ICER for survival was 260,201,000-371,011,000 Korean Won (KW; 1USD=1,088 KW) for the upper-gastrointestinal (UGI) tract over non-screening. Endoscopy ICERs were lower (119,099,000-178,700,000 KW/survival) than UGI. To increase 1 life-year, additional costs of approximately 14,466,000-15,014,000 KW and 8,817,000-9,755,000 KW were required for UGI and endoscopy, respectively. Endoscopy was the most cost-effective strategy for males and females. With regard to sensitivity analyses varying based on the upper age limit, endoscopy NCSP was dominant for both males and females. For males, an upper limit of age 75 or 80 years could be considered. ICER estimates for LYS indicate that the gastric cancer screening program in Korea is cost-effective. Conclusion: Endoscopy should be recommended as a first-line method in Korea because it is beneficial among the Korean population.

• Korean Journal of Child Studies
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• v.9 no.2
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• pp.1-28
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• 1988

The purpose of this study was to develop a behavior rating scale for the evaluation of children's development for utilization by preschool teachers. The procedures for the study included content validation, pilot test, and main study. A total of 97 items were retained after the content validation and pilot test. The items of the scale were grouped into five areas (physical, language, cognitive, emotional, and social development) and 11 sub-areas. The resulting "Behavior Rating Scale for Preschool Children" was administered to 479 boys and girls, 3-6 through 6-5 years of age, selected from 10 different kindergartens and early education centers in Seoul, Pusan, and Chonju. The analysis of data was done with SPSS computer programs, including item analysis, Cronbach's ${\alpha}$ for reliability, factor analysis to test construct validity, two-way ANOVA to test age and sex differences, and percentile norms. The 97 items of the scale were found to be satisfactory in terms of item discrimination with indices ranging from .31 to .73. Cronbach's ${\alpha}$ was .98 for the total scale and ranged from .87 to .93 in specific domains, which was considered satisfactory. The factors extracted from each area were consistent with the educational objectives of the Yonsei Open Education Program except for emotional development. The intercorrelations among the domains were relatively high, ranging from .56 to .81. Age differences were significant in cognitive, physical, and language development, but not significant in social and emotional development. Sex differences were significant in all areas with girls higher on the average than the boys. Percentile ranks were drived from the total score for each age group and quartiles were calculated for sub-scores in each domain.

• Educational Technology International
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• v.17 no.1
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• pp.59-85
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• 2016

The purpose of the study is to report differences in the effects of learner characteristics on the self-regulated learning (SRL) abilities between Chinese and Korean distance learners by using a structured SRL scale. A standardized 54-item self-regulated learning scale (SRAS) was used. The reliability was tested both in China and Korea which showed the scale had good reliability. The comparative study were conducted by administering the SRAS on 1999 Chinese distance learners from the Open Distance Education Center of Beijing Normal University and 1941 Korean distance learners from H Cyber University. Data on four dimensions of SRL - planning, control, regulating, and evaluation - were analyzed using 't-test' and 'ANOVA' with regards to the learner characteristics such as gender, age, prior education level, semesters, location and major. Results indicated that the average participant had an above medium level of SRL ability in all of the four dimensions. There were significant differences in the self-regulated learning ability between Chinese and Korean distance learners. Chinese distance learners scored higher in SRAS than Korean distance learners. The effects of learner characteristics on the SRL ability showed different patterns in the two countries. As for gender, male learners scored better in SRL than female learners in China, whereas it was just the opposite in Korea. No age differences were found in China, but Korean data exhibited a consistent age effect in all dimensions. In Korea, the age group older than 46 scored the highest, followed by the group between 35 to 45 years old, the group between 26 to 35 years old and the group younger than 25. As for location, Korean distance students from metropolitan were better than those from other regions, whereas it was on the contrary in China, albeit the location effect was not statistically significant. Prior education level had a clear and consistent effect on the SRL ability in both countries: the distance learners from junior colleges had better planning, regulating and evaluating abilities than those who came from senior high schools. These results have been discussed in various contexts of distance/online education as well as in relation to different culture between China and Korea. The results will also have implications for designing distance and online learning generally.

• Analytical Science and Technology
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• v.29 no.6
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• pp.269-276
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• 2016

Gosan-ri site is known as the early Neolithic cultural heritage, in which an archaic plainware, called as the Gosan-ri-type pottery, was excavated regarding as the first pottery manufactured in Korea. In this study, OSL dating was carried out to five soil layer samples collected in stratigraphic cross-section for evaluating the formation and occupation of the Gosan-ri site. Paleodose of each soil sample was calculated using the single aliquot regenerative dose (SAR) method with preheat of $220^{\circ}C$ and finally determined using maximum age model, considering its deposition process. The OSL age was determined from the ratio of paleodose to annual dose rate. From the resultant OSL ages and the related 14C dates, it was concluded that the Gosan-ri site was formed after 9,000 BC and a variety of cultural feature including the Gosan-ri-type pottery were occupied ranging from the early Neolithic to the middle of 4,000 BC. Finally, the Gosan-ri site was discarded in the middle of 4,000 BC and has been arrived at present through natural deposits.

• Communications of Mathematical Education
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• v.31 no.4
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• pp.367-387
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• 2017

The educational environment in the digital age of the 21st century definitely affects teaching and learning methods to be changed. In addition, the perceptions and methods of mathematics education in the digital age have also been changing. This study proposes a university mathematics education model suitable for the digital age, which makes full use of the internet/digital environment and leads the students to participate in the learning processes. We apply the proposed model to Linear Algebra course, and present a concrete method of teaching and learning model including evaluation. This will be the first study on how to organize and operate digital courses in Korea in accordance with the mathematics education in the digital era which is rapidly spreading around the world.