• 대한화학회지
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• 제24권3호
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• pp.201-208
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• 1980

CNDO/2 MO 계산방법을 사용하여 양성자화된 아세트알데히드와 알코올 및 양성자화된 아세트산과 알코올간의 기체반응에 대한 전이상태구조를 최적화하였다. 계산으로 얻은 구조에 따르면 전자의 반응은 공격하는 알코올의 alkyl-O 절단으로 진행되고 후자의 반응은 acyl-O 절단으로 진행될 것임을 보여주어 실험결과와 일치하였다. 또 반응물질들의 eigenvector 성질들로 판단할 때 전자의 반응은 charge controlled인 반면 후자의 반응은 orbital controlled임을 예측케 해주었다. Caserio 등이 제안한 전이상태를 가정한 CNDO/2 활성화에너지 결과에 따르면 후자의 경우는 실험결과와 일치하는 알코올의 반응성 순위를 주지만 전자의 경우는 실험결과와 반대되는 순위를 주었다.

• 대한기계학회논문집A
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• 제27권1호
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• pp.66-76
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• 2003

The arbitrary V-notched crack problem is considered. The general expressions for the stress components on this problem are obtained as explicit series forms composed of independent unknown coefficients which are denoted by coefficients of eigenvector. For this results eigenvalue equation is performed first through introducing complex stress functions and applying the traction free boundary conditions. Next solving this equation, eigenvalues and corresponding eigenvectors are obtained respectively, and finally inserting these results into stress components, the general equations are obtained. These results are also shown to be applicable to the symmetric V-notched crack or straight crack. It can be shown that this solutions are composed of the linear combination of Mode I and Mode II solutions which are obtained from different characteristic equations, respectively. Through performing asymptotic analysis for stresses, the stress intensity factor is given as a closed form equipped with the unknown coefficients of eigenvector. In order to calculate the unknown coefficients. based on these general explicit equations, numerical programming using the overdetermined boundary collocation method which is algorithmed originally by Carpenter is also worked out. As this programming requires the input data, the commercial FE analysis for stresses is performed. From this study, for some V-notched problems, unknown coefficients can be calculated numerically and also fracture parameters are determined.

• 디지털융복합연구
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• 제14권9호
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• pp.301-308
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• 2016

양질의 논문을 생산하고 자신의 논문이 저명한 학술지에 게재되어 보다 큰 영향력을 가지는 것은 모든 연구자들이 원하는 바라고 할 수 있다. 이 논문은 사회연결망분석을 통해 행정학과 정책학 분야의 일반학술지 9개를 선정하여 네트워크를 구성하고 이 9개 학술지들 간의 상호인용분석을 통해 각 학술지들이 네트워크상에서 가지는 영향력을 분석하였다. 네트워크상에서의 영향력에 대해 각각 의미하는 바가 다른 연결중심성, 베타중심성, 고유벡터중심성의 3개 중심성지수를 통해 분석한 결과 한국행정학보가 행정학과 정책학분야를 통틀어 가장 큰 영향력을 가지는 학술지로 나타났고 한국정책학회보가 그 뒤를 이었다. 그리고 중심성지수의 선택이 달라질 때 마다 학술지들이 가지는 영향력 순위가 달라지는 경향을 보였다.

• 한국통신학회논문지
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• 제19권12호
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• pp.2303-2312
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• 1994

등간격 선형 어레이로 입사하는 다중 협대역 신호를 분리 추정하기 위한 고해상도 알고리즘을 제안한다. 코히어런트 신호로 인한 여러가지 문제점을 해결하기 위하여 잡음 고유벡터를 기본으로 한 방법들이 제안되어 왔다. 그러나, 여러가지 이유로 인하여 이러한 방법들은 뛰어난 분해능을 보여 주지 못한다. 그리하여, 제안된 알고리즘은 공분간 행렬의 큰 고유치에 대응하는 신호 고유벡터가 가지고 있는 근본적인 성질을 이용하여 등간격 선형 어레이로 입사하는 평면파의 도래각 추정 문제를 해결한다. 시뮬레이션을 통하여 비교 분석한 결과 제안된 방법이 MUSIC 및 spatial smoothed MUSIC 방법 보다 높은 분해성능을 보여 주었다.

• 대한기계학회논문집A
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• 제28권5호
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• pp.503-510
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• 2004

In this paper, the well-conditioned observer for a stochastic system is designed so that the observer is less sensitive to the ill-conditioning factors in transient and steady-state observer performance. These factors include not only deterministic uncertainties such as unknown initial estimation error, round-off error, modeling error and sensing bias, but also stochastic uncertainties such as disturbance and sensor noise. In deterministic perspectives, a small value in the L$_{2}$ norm condition number of the observer eigenvector matrix guarantees robust estimation performance to the deterministic uncertainties. In stochastic viewpoints, the estimation variance represents the robustness to the stochastic uncertainties and its upper bound can be minimized by reducing the observer gain and increasing the decay rate. Both deterministic and stochastic issues are considered as a weighted sum with a LMI (Linear Matrix Inequality) formulation. The gain in the well-conditioned observer is optimally chosen by the optimization technique. Simulation examples are given to evaluate the estimation performance of the proposed observer.

• Industrial Engineering and Management Systems
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• 제11권1호
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• pp.54-69
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• 2012

Chan and Qi (SCM 8/3 (2003) 209) developed an innovative measurement method that aggregates performance measures in a supply chain into an overall performance index. The method is useful and makes a significant contribution to supply chain management. Nevertheless, it can be cumbersome in computation due to its highly complex algorithmic fuzzy model. In aggregating the performance information, weights used by Chan and Qi-which aim to address the imprecision of human judgments-are incompatible with weights in additive models. Furthermore, the default assumption of linearity of its scoring procedure could lead to an inaccurate assessment of the overall performance. This paper addresses these limitations by developing an alternative measurement that takes care of the above. This research integrates three different approaches to multiple criteria decision analysis (MCDA)-the multiattribute value theory (MAVT), the swing weighting method and the eigenvector procedure-to develop a comprehensive assessment of supply chain performance. One case study is presented to demonstrate the measurement of the proposed method. The performance model used in the case study relies on the Supply Chain Operations Reference (SCOR) model level 1. With this measurement method, supply chain managers can easily benchmark the performance of the whole system, and then analyze the effectiveness and efficiency of the supply chain.

• 인터넷정보학회논문지
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• 제16권5호
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• pp.39-47
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• 2015

그래프에서 각 노드에 대해 그래프 내의 중요도를 나타내는 중심성(centrality)을 계산할 수 있고, 그 값에 따라 각 노드는 중요도 순위(ranking)를 갖는다. 중심성을 나타내는 방법으로는 여러 척도가 있는데, 본 연구에서는 연결도(degree) 중심성, 밀접도(closeness) 중심성, 특성벡터(eigenvector) 중심성, betweenness 중심성에 국한하여 연구를 수행하였다. 본 연구는 그래프에서 에지를 하나 추가할 경우, 그래프 내 노드 전체에 미치는 노드의 중심성 및 순위의 변화를 실험계산을 통해 확인한다. 그리고, 추가되는 에지가 노드 전체의 중심성 및 순위에 미치는 영향은 그래프의 형태에 따라 달라진다는 것을 PCA(Principal Component Analysis)를 통해 밝혔다. 이 사실은 그래프의 구조적 특성을 구분하는 방법으로도 사용될 수 있다.

• 임상간호연구
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• 제25권3호
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• pp.209-220
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• 2019

Purpose: A significant amount of public opinion about nurse bullying is expressed on the internet. The purpose of this study was to analyze the linkage structures among words extracted from comments on internet articles related to nurse workplace bullying using semantic network analysis. Methods: From February 2018 to April 2019, comments made on news articles posted to the Daum and Naver web portal containing keywords such as "nurse", "Taeum", and "bullying" were collected using a web crawler written in Python. A morphological analysis performed with Open Korean Text in KoNLPy generated 54 major nodes. The frequencies, eigenvector centralities, and betweenness centralities of the 54 nodes were calculated and semantic networks were visualized using the UCINET and NetDraw programs. Convergence of iterated correlations (CONCOR) analysis was performed to identify structural equivalence. Results: This paper presents results about March 2018 and January 2019 because these months had highest number of articles. Of the 54 major nodes, "nurse", "hospital", "patient", and "physician" were the most frequent and had the highest eigenvector and betweenness centralities. The CONCOR analysis identified work environment, nurse, gender, and military clusters. Conclusion: This study structurally explored public opinion about nurse bullying through semantic network analysis. It is suggested that various studies on nursing phenomena will be conducted using social network analysis.

• 산업경영시스템학회지
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• 제26권3호
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• pp.58-66
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• 2003

The cut tree approach of Montreuil and Ratliff [16] and eigenvector approach [10] are used to automatically draw a feasible facility layout with aisle structure. The department arrangement can minimize an aisle distance criterion considering door locations and dimension constraints. The aisle distance is measured by the door to door distance between departments. An eigenvector and cut tree approaches [1] are implemented based on the branch and bound technique in Kim et al. [2] in order to obtain feasible layouts. Then, the algorithm to fix the door location of each department is developed. After the door locations are determined, the factory layout is evaluated in terms of aisle distance. The aisle structure is obtained by expanding the original layout. The solution is kept until we will find better factory layout. The proposed approach based on the branch and bound technique, in theory, will provide the optimal solution. If the runs are time and/or node limited, the proposed method is a strong heuristic. The technique is made further practical by the fact that the solution is constrained such that the rectangular shape dimensions length(l) and width(w) are fixed and a perfect fit is generated if a fit is possible.

• The Plant Pathology Journal
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• 제39권3호
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• pp.245-254
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• 2023

The plant microbiota plays a crucial role in promoting plant health by facilitating the nutrient acquisition, abiotic stress tolerance, biotic stress resilience, and host immune regulation. Despite decades of research efforts, the precise relationship and function between plants and microorganisms remain unclear. Kiwifruit (Actinidia spp.) is a widely cultivated horticultural crop known for its high vitamin C, potassium, and phytochemical content. In this study, we investigated the microbial communities of kiwifruit across different cultivars (cvs. Deliwoong and Sweetgold) and tissues at various developmental stages. Our results showed that the microbiota community similarity was confirmed between the cultivars using principal coordinates analysis. Network analysis using both degree and eigenvector centrality indicated similar network forms between the cultivars. Furthermore, Streptomycetaceae was identified in the endosphere of cv. Deliwoong by analyzing amplicon sequence variants corresponding to tissues with an eigenvector centrality value of 0.6 or higher. Our findings provide a foundation for maintaining kiwifruit health through the analysis of its microbial community.