• Applied Microscopy
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• 제47권3호
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• pp.187-202
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• 2017

The classical electron band theory is a powerful tool to describe the electronic structures of solids. However, the band theory and corresponding density functional theory become inappropriate if a system comprises localized electrons in a scenario wherein strong electron correlations cannot be neglected. $SrRuO_3$ is one such system, and the partially localized d-band electrons exhibit some interesting behaviors such as enhanced effective mass, spectral incoherency, and oppression of ferromagnetism and itinerancy. In particular, a Metal-Insulator transition occurs when the thickness of $SrRuO_3$ approaches approximately four unit cells. In the computational studies, irrespective of the inclusion of on-site Hubbard repulsion and Hund's coupling parameters, correctly depicting the correlation effects is difficult. Because the oxygen atoms and the symmetry of octahedra are known to play important roles in the system, scrutinizing both the electronic band structure and the lattice system of $SrRuO_3$ is required to find the origin of the correlated behaviors. Transmission electron microscopy is a promising solution to this problem because of its integrated functionalities, which include atomic-resolution imaging and electron energy loss spectroscopy.

• 한국멀티미디어학회논문지
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• 제6권1호
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• pp.67-77
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• 2003

멀티미디어에 삽입된 워터마크의 검출은 저작권 보호 및 인증 분야에서 매우 중요한 역할을 한다. 최근 워터마크의 검출에 많이 사용되는 유사도 기반 알고리즘은 대상 영상의 분포 특성을 이용하지 않기 때문에 검출 성능이 떨어지는 단점을 가진다. 따라서 본 논문에서는 웨이블릿 변환 영역에서 효율적인 워터마크 검출 알고리즘을 제안하였다. 제안한 워터마크 검출 알고리즘은 통계적 판정법에 근거하여 Bayes판정 이론, Neyman-Pearson 정리, 및 웨이블릿 계수들의 분포 모델을 이용한다. 따라서 제안한 검출 알고리즘에서는 주어진 오류 검출 확률에 대하여 간과 검출 확률을 최소화할 수 있는 장점이 있다. 제안한 검출 알고리즘의 성능 평가는 견고성 측면에서 수행되었고, 실험 결과로부터 제안한 알고리즘이 유사도 기반 알고리즘에 비하여 우수한 성능을 나타냄을 확인하였다.

• Journal of Chest Surgery
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• 제19권4호
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• pp.558-562
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• 1986

The extracorporeal circulation has been much improved recently, but has yet much complex problems such as the protein denaturation and the activation of the complement system by the exposure of the blood to the foreign surface, which may result in such as the postperfusion syndrome. We studied the changes of the plasma protein fractions by the electrophoresis and the complement consumption [C3, C4] by the immunodiffusion method in the patients undergoing cardiac operation from Mar. 1, 1986 to Aug. 31, 1986. The results were summarized as follows: 1. y-globulin fraction was decreased [p<0.02 by paired t-test, N=25], but a,-globulin was increased [p<0.001 by paired t test, N=25] after operation. 2. C3,C4 were significantly reduced [p<0.001 by paired t-test, N=14] postoperatively and normalized from 24 hours after operation. 3. The consumption of C3,C4 had significant linear correlation [correlation coefficient r=0.97] and C, was more markedly reduced comparing with C3, which probably means the complement activation by classical pathway in our bubble oxygenator group.

• 과학교육연구지
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• 제34권1호
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• pp.155-163
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• 2010

이 연구의 목적은 본 연구는 영재선발도구로서 지필 검사 문항의 적합성에 대한 검토를 위해 초등과학영재교육원의 학생 선발에 지난 3년간 사용된 지필 검사 문항들을 대상으로 문항 분석을 하여, 영재교육 대상자 선발 방법에 대한 새로운 전형방식에 주는 교훈을 얻기 위하여 실시하였다. 문항 분석 결과, 평균 문항 난이도와 변별도는 대체로 양호한 편이었으며, 교과 및 내용별로도 큰 차이가 없는 것으로 분석되었다. 서술형 문항이 객관형 문항에 비해 어렵게 출제되었으며, 변별력이 높았던 것으로 분석되었다. 특정 문항들과 총점과의 상관관계에서 객관형 문항의 경우는 물질 문항과, 자료변환 및 자료해석 문항에서 가장 높은 상관이 나타났으며, 서술형 문항의 창의성 문항이 총점과의 상관이 가장 높은 것으로 분석되었다. 선발 시험에 응시한 학생들의 성별의 따른 차이를 t 검증으로 분석한 결과, 자료변환 및 자료해석과 창의성에서 남학생의 평균이 유의미하게 높은 것으로 나타났다.

• Communications for Statistical Applications and Methods
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• 제23권5호
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• pp.433-444
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• 2016

When we observe binary responses in a cluster (such as rat lab-subjects), they are usually correlated to each other. In clustered binomial counts, the independence assumption is violated and we encounter an extra-variation. In the presence of extra-variation, the ordinary statistical analyses of binomial data are inappropriate to apply. In testing the homogeneity of proportions between several treatment groups, the classical Pearson chi-squared test has a severe flaw in the control of Type I error rates. We focus on modifying the chi-squared statistic by incorporating variance inflation factors. We suggest a method to adjust data in terms of dispersion estimate based on a quasi-likelihood model. We explain the testing procedure via an illustrative example as well as compare the performance of a modified chi-squared test with competitive statistics through a Monte Carlo study.

• Structural Engineering and Mechanics
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• 제3권4호
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• pp.299-312
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• 1995

A new reinforcing steel model which is embedded inside a concrete element and also accounts for the effect of bond-slip is developed. Unlike the classical bond-link or bond-zone element using double nodes, the proposed model is considering the bond-slip effect without taking double nodes by incorporation of the equivalent steel stiffness. After calculation of nodal displacements, the deformation of steel at each node can be found through the back-substitution technique from the first to the final steel element using a governing equation constructed based on the equilibrium at each node of steel and the compatibility condition between steel and concrete. This model results in significant savings in the number of nodes needed to account for the effect of bond-slip, in particular, when the model is used for three dimensional finite element problems. Moreover a new nonlinear solution scheme is developed in connection with this model. Finally, correlation studies between analytical and experimental results and several parameter studies are conducted with the objective to establish the validity of the proposed model.

• Structural Engineering and Mechanics
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• 제46권6호
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• pp.853-868
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• 2013

The comparison of the effectiveness of artificial neural network (ANN) and linear regression (LR) in the prediction of strain in tie section using experimental data from eight high-strength-self-compact-concrete (HSSCC) deep beams are presented here. Prior to the aforementioned, a suitable ANN architecture was identified. The format of the network architecture was ten input parameters, two hidden layers, and one output. The feed forward back propagation neural network of eleven and ten neurons in first and second TRAINLM training function was highly accurate and generated more precise tie strain diagrams compared to classical LR. The ANN's MSE values are 90 times smaller than the LR's. The correlation coefficient value from ANN is 0.9995 which is indicative of a high level of confidence.

• Bulletin of the Korean Chemical Society
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• 제32권2호
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• pp.439-443
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• 2011

Using the projection operator technique, a reduced density matrix theory for linear absorption spectrum of energy transfer systems is developed for the theoretical absorption line shape of the systems with non-Condon transitions. As an application, we considered a model system of OH vibrations of water. In the present model calculation, the OH vibration modes are coupled to each other via intra-molecular coupling mechanism while their intermolecular couplings are turned off. The time-correlation functions appearing in the formulation are calculated from a mixed quantum/classical mechanics method. The present theory is successful in reproducing the exact absorption line shape. Also the present theory was improved from an existing approximate theory, time-averaged approximation approach.

• 대한기관식도과학회지
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• 제4권2호
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• pp.193-196
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• 1998

Gastroesophageal reflux (GER) has been considered one of major causes in patient with globus symptom. Diagnostic methods for GER are gastroesophagoscopy, acid perfusion test esophagogram, esophageal manometry, 24-hour double probe pH-metry, and so on. According to the literature, positive rate of GER on esophagogram was reported variably from 4.7% to 45.9% and the outcome of classical treatment with antacid and prokinetic agent was reported from 70% to 84%. We reviewed the medical records of 81 patients with globus symptom. Each patient had been performed esophagogram and treated with antacid and prokinetic agent. Positive rate of GER on esophagogram was 46.9%. Complete resolution and improvement of globus symptom was 79% overally, 92% in positive group of GER rut esophgogram, and 72% in negative group. Considering aspects of time-cost and compliance of patient esophagogram is one of the screening methods of GER in patients with globus symptom. Antacid and prokinetic agent is recommended in treatment of patients with globus symptom.

• 한국농공학회논문집
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• 제49권1호
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• pp.3-13
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• 2007

In this study, spatial characteristics of rainfall in Imha basin were investigated by cross-correlation analysis among rainfall gaging stations and rainfall-runoff analysis used in HEC-HMS model for analysis of influence on observed rainfall. The Kriging technique was applied to rain(all analysis in Imha basin to reflect spatial characteristics of regional rainfall. Their results are compared to rainfall-runoff data with spatially distributed rainfall data as well as the classical thiessen method. The results by kriging technique approached by geostatistical method could reflect spatial characteristics of regional rainfall properly in Imha basin.