• Computational Structural Engineering
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• v.4 no.1
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• pp.20-27
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• 1991

본 논문에서는 유체-구조 상호작용해석의 일종의 3차원 접수구조물의 진동해석을 효과적으로 수행하기 위한 해석방법을 제시하기 위하여 동적재해석기법을 검토하였다. 접수구조물의 유한구조 상호작용해석 결과는 구조진동의 관심 주파수역에서는 3차원 연성 부가수질량으로 표현되는 관성력으로 나타난다. 따라서 구조질량행렬에 부가수질량 행렬이 더해져서 전체 관성력으로 표현된다. 이 부가수질량을 추가질량으로 보고 재해석기법을 응용하는 방법을 수치실험을 통해 검증하였다. 이 때 재해석기법이 갖추어야 할 조건은 원구조의 질량과 거의 같은 정도의 질량이 추가되고 또한 완전 연성질량이 추가된 경우에도 정확한 해를 주어야 한다는 것이다. 이를 검증하기 위해 직접재해석기법과 섭동법을 이용한 재해석기법으로 4질량 스프링지지구조에 대한 해석을 수행한 결과 직접재해석기법의 응용이 적합함을 쉽게 입증할 수 있었다. 접수구조물의 예로는 3차원 잠수주상체에 대해 접수진동해석을 수행하였으며 그 결과 선체진동해석에 전통적으로 이용되고 있는 2차원 부가수질량과 3차원 수정계수를 사용한 기준차수법에서는 수지모드와 수평-비틔 연성모드와 같이 서로 독립적인 모드에 대해서는 따로 진동해석을 수행해 주어야 하는 단점이 발견되었다. 이 단점을 보완한 각 모드의 3차원 수정계수행렬을 이용한 재해석기법을 도입하여 모드에 상관없이 동시에 해를 구할 수 있었다. 그러나, 이 방법은 3차원 수정계수가 구해져 있는 경우에 한해서만 적용가능하며 실제 선체진동의 경우에는 10Hz 미만의 저차 주선체 진동에 한해서만 적용가능한 방법이다. 고차의 진도옴드에는 3차원 수정계수를 구할 수 없기 때문에 유체-구조 상호작용 해석결과로부터 얻은 3차원 연성 부가수질량을 이용하게 되며 이 때 이 행렬이 접수구조 표면의 전 자유도와 연성되어 있기 때문에 방대한 방정식을 푸어야 하지만 직접재해석기법을 적용함으로써 정확한 해를 구할 수 있었다. 또한 3차원 부가수질량을 이용한 직접재해석기법은 종래의 2차원 부가수질량과 3차원 수정계수를 이용한 방법에 비해 해석시간 면에서도 전혀 불리한 점이 없는 경제적 방법임이 밝혀졌다. 앞으로 Slamming 혹은 수중폭파 등의 충격하중에 의한 천이 구조응답 해석을 위한 효과적인 방법에 대해서도 연구결과를 발표할 계획이다.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2000.11a
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• pp.91-95
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• 2000

계면활성제를 이용하여 토양에 존재하는 유기 오염물질을 제거하는데 있어서, 계면활성제가 토양과의 상호작용시 투수계수를 상당히 ($10^2$ 이상) 감소시키면 이 복원방법은 실용성이 없다 그러므로 본 연구의 목적은 선택된 계면활성제와 투수계수 사이의 상관 관계를 고찰하는데 있다. 본 연구 결과 계면활성제(DOSL) 사용 후 증류수와의 상대적 비교치로써 투수계수는 21~35 % 감소하였다. 이 감소 수치의 의미는 선택된 계면활성제(DOSL)는 토양 복원 연구에 사용될 수 있음을 보여준다.

• Nuclear Medicine and Molecular Imaging
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• v.42 no.6
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• pp.435-443
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• 2008

Purpose: Gated myocardial perfusion SPECT provides not only myocardial perfusion status but also various functional parameters of left ventricle. We compared left ventricular ejection fraction, end-diastolic volume, LV mass by cardiac SPECT using Quantitative Gated SPECT (QGS), 4D-MSPECT software and standard 2D-echocardiography. Materials and Methods: One hundred fourteen patients (male 51, female 63; 29-85 years old, mean $61.3\;{\pm}\;13.3$ years old) with normal perfusion status on Tc-99m tetrofosmin gated myocardial perfusion SPECT were analyzed retrospectively. Ejection fraction (LVEF), End-diastolic volume (LVED), LV mass (LVM) were calculated using QGS, 4D-MSPECT, and LVEF, LVM using 2D-echocardiography. Statistical analysis including Bland-Altman plot was performed using $MedCalc^{(R)}$ (MedCalc software, Mariakerke, Belgium). Results: The correlation of LVEF between methods was good: 0.95/0.96 (stress/rest) between QGS and 4D-MSPECT, 0.79 between QGS and echocardiography, 0.79 between 4D-MSPECT and echocardiography (p<0.001). Using Bland-Altman plot, the 95% confidence interval of agreement between QGS and 4D-MSPECT ranged from -12.7% to 7.3% / from -12.2% to 6.5% (stress/rest). The agreement between QGS and echocardiography, 4D-MSPECT and echocardiography ranged from -17.4% to 24.0%, and -14.8% to 27.0% respectively. The correlation of LVM between methods was also good: 0.95 between QGS and 4D-MSPECT, 0.76 between QGS and echocardiography, 0.73 between 4D-MSPECT and echocardiography (p<0.001). The 95% confidence interval of agreement between QGS and 4D-MSPECT ranged from -33.8g to 14.1g (stress/rest), The 95% confidence interval of agreement between QGS and echocardiography, 4D-MSPECT and echocardiography ranged from -148.7 g to 21.8. g, and -142.8 g to 35.5 g, respectively. Conclusion: There was a good correlation for LVEF, LVEO, LVM among methods (QGS, 4D-MSPECT, echocardiography), but the variance between methods was big. Therefore, the functional parameters by each method cannot be used interchangeably.

• Journal of Korean Society of Transportation
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• v.30 no.4
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• pp.33-42
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• 2012

Recent development and penetrating expansion in ICT(Information and Communication Technology) has brought considerable improvements in transportation services. However, there is a controversial debate whether transportation and communications behave as substitutes or as complements to one another. On this subject, recent studies considered those two industries as services, but transportation and communications are broadly put for intermediary goods into other industries. Hence, it is essential to examine this issue from understanding their relationships to each other with respect to manufacturing and services. In this study, input-output tables of benchmark years from 1980 to 2005 have been analysed to explore the relationships between transportation and communications using Spearman's correlation analysis. The results show that both industries had complementary roles over the period, but, to some extent, changed into substitution roles in some categories.

• Proceedings of the Korea Water Resources Association Conference
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• 2008.05a
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• pp.2095-2099
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• 2008

본 연구에서는 충분히 보정되고 검증되어진 SWAT-K 모형으로부터 생성된 자료를 이용하여 강우-유출-유사 사이의 상호 관계를 도출해 보았다. 소양댐 상류유역을 대상으로 유역내 각 지점별 강우에 따른 유출 및 유사, 유출과 유사의 상호 관계 등을 도시하여 검토한 결과, 약 40 mm 이하의 강우에 대해서는 유사 발생이 많지 않음을 알 수 있었으며, 그 이상의 강우에 대해서 강우와 유사 사이에 이차원 관계의 회귀식을 유도할 수 있었다. 또한, 유출과 유사 사이에도 거듭제곱 형태의 관계식을 유도할 수 있었으며 그에 따른 결정 계수도 높게 나타나 상호간의 회귀식이 매우 상관성이 높음을 알 수 있었다. 이와 같은 관계로부터 향후 복잡한 모형을 이용하지 않아도 대상유역의 특정 지역에 대해 강우로부터 유출이나 유사를 추정하는데 비교적 간편하고 신뢰성 있게 적용될 수 있을 것으로 판단된다.

• The Journal of the Convergence on Culture Technology
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• v.9 no.4
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• pp.223-228
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• 2023

This study examines the relationship between teacher-perceived teaching efficacy and happiness and teacher-infant interaction, and analyzes the effect of teaching efficacy and happiness on teacher-infant interaction. The purpose was to reveal that it was an important variable in the quality of action. Frequency analysis and descriptive statistics analysis were conducted for the Korean Children's Panel 7th year (2014) data, and Pearson's moment-moment correlation coefficient was calculated for correlation analysis between variables. Multiple regression analysis was conducted to examine the influence of teachers' teaching efficacy and happiness on teacher-infant and infant-infant interactions. The research results were as follows. First, teachers' teaching efficacy, teacher happiness, teacher-infant, and infant-infant interactions were all found to have significant positive correlations. Second, teachers' teaching efficacy was found to have a significant effect on teacher-infant and infant-infant interactions, and the influence increased when teacher's happiness was added. Therefore, we need to come up with a plan to increase teachers' teaching efficacy and teacher happiness at the same time so that the quality of teacher-infant and infant-infant interactions can be meaningfully improved.

• Journal of Korean Tunnelling and Underground Space Association
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• v.3 no.1
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• pp.27-35
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• 2001

Four road tunnels, which consists of biotite gneiss and granite gneiss and shows a similar geological conditions, were selected in this study. Laboratory and field tests, the rock mass rating for the four tunnels were conducted. A regression analysis was performed to find out the correlations of test results. It was proposed an equation of reduction factor which can assess the deformation modulus for biotite gneiss and granite gneiss. It was also found that there was a close correlation between Q and RQD in four tunnels according to the analysis between RMR and Q, RMR and RQD, Q and RQD and laboratory and field tests.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.5 no.1
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• pp.118-132
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• 1994

The purpose of this study was to compare communication and mother-child interactions of reactive attachment disordered children with normal children. The subjects were 24 children and their mothers participated in this study'12 reactive attachment disordered children and mothers, 12 normal children and mothers. The mother and her child were brought into a p]lay room and the mother was instructed to play with her child as she normally would at home. The play situations were videotaped. Tapes were transcribed and transcribed data was analyzed with 13 mutually exclusive categories encompassing pragmatic functions represented in communication form the early stage of multiword speech in childhood. The tapes were analyzed with 10 behavioral mother-child interaction patterns. As the statistical method, t-test and correlation was calculated. The results of this study were as follows : 1) Reactive attachment disordered children used significantly fewer 'filler', 'information', 'requests', 'describes' and 'disscus self'. 2) Reactive attachment disordered children's mother used significantly fewer 'filler' and 'names'. 3) Reactive attachment disordered children used significantly more 'independent play', fewer 'intiates interaction', 'responsiveness' and 'answer' Reactive attachment disordered children's mother used more 'control play', 'observe' and fewer 'initiates interaction'. 4) Children's communication patterns were related lo mother·'s communication and mother-child interaction types. Children's 'filler', 'information requests', 'describes' and 'disscus self' were consistantly related to mother's 'filler' and 'names', (Children's 'filler', 'information requests', 'describes'. 'disscus self' and mother-child's intiates interaction 'responsivness' were significantly positively correlationed and 'independant play', 'control play', 'observation' were significantly negatively correlationed. The results of reveal that communication and mother-child interaction pattern of reactive attachment disordered group was different from normal group and children's communication pattern were influenced by mother's communication and interaction patterns.

• Korean Journal of Applied Biomechanics
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• v.18 no.3
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• pp.1-10
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• 2008

One of the major factors affecting maneuverability of an athlete is frictional force caused at an outsole of his shoe. The magnitude of the frictional force is closely related to pattern and hardness of outsole and roughness of ground or floor. This study then focuses on the effect of outsole pattern of sports shoes on the frictional force. After surveying outsole patterns of sports shoes in markets, we select 4 types of outsole patterns, such as straight, W, O, and wave as primary outsole patterns of sports shoe and we also select depth, pitch and slope as design parameters of each pattern. Corresponding to those patterns and design parameters, various outsole specimen are prepared for frictional experiments. After performing frictional tests with those specimen, coefficients of friction(COF) are collected and analyzed with a statistical tool to draw useful conclusion.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.1D
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• pp.59-66
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• 2006

This study was to construct the linear density predictive models on the on-ramp junctions in urban freeway. From the analyses of the real-time traffic characteristic data, and the construction and verification of the linear density predictive models, the models showed a considerable explanatory power with the determination coefficients ($R^2$) of over 0.7 between the density and speed data. Also, they showed a considerably high correlativeness with the correlation coefficients (r) of over 0.8 between the calculated density data and the expected ones estimated by the models.