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图论法在基于混合网格的油藏数值模拟软件设计中的应用 被引量:1
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作者 王涛 李秀生 程林松 《石油大学学报(自然科学版)》 EI CSCD 北大核心 2002年第5期52-54,共3页
在油藏数值模拟中 ,井模型的选取直接影响整个计算结果。充分考虑了井附近的渗流特征 ,建立了更符合井区域渗流规律的井模型。将图论理论应用于油藏数值模拟软件的设计中 ,使计算变得迅捷 ,有效地实现了对复杂形状网格的管理。根据图论... 在油藏数值模拟中 ,井模型的选取直接影响整个计算结果。充分考虑了井附近的渗流特征 ,建立了更符合井区域渗流规律的井模型。将图论理论应用于油藏数值模拟软件的设计中 ,使计算变得迅捷 ,有效地实现了对复杂形状网格的管理。根据图论网格管理系统的特点 ,采用全隐式和IMPES相结合的数值算法 ,编制了油藏数值模拟软件。简单算例的计算结果表明 ,采用新井模型的油藏数值模拟软件 ,其计算结果比传统的数模软件更能准确合理地反映井底流压的变化。 展开更多
关键词 图论生 混合网格 油藏 数值模拟软件 井模型 网格 图论 设计 应用
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TWO IMPROVED GRAPH-THEORETICAL CLUSTERING ALGORITHMS 被引量:2
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作者 王波 丁军娣 陈松灿 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI 2012年第3期263-272,共10页
Graph-theoretical approaches have been widely used for data clustering and image segmentation recently. The goal of data clustering is to discover the underlying distribution and structural information of the given da... Graph-theoretical approaches have been widely used for data clustering and image segmentation recently. The goal of data clustering is to discover the underlying distribution and structural information of the given data, while image segmentation is to partition an image into several non-overlapping regions. Therefore, two popular graph-theoretical clustering methods are analyzed, including the directed tree based data clustering and the minimum spanning tree based image segmentation. There are two contributions: (1) To improve the directed tree based data clustering for image segmentation, (2) To improve the minimum spanning tree based image segmentation for data clustering. The extensive experiments using artificial and real-world data indicate that the improved directed tree based image segmentation can partition images well by preserving enough details, and the improved minimum spanning tree based data clustering can well cluster data in manifold structure. 展开更多
关键词 image segmentation data clustering graph-theoretical approach directed tree method minimum spanning tree method
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DISCUSSION ON MINIMUM FLOW MODEL FOR ITS RELATIONSHIP WITH HAMILTONIAN PATH PROBLEM 被引量:1
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作者 NINGXuan-xi 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI 2004年第4期322-325,共4页
A negative example shows that the model given by Mason Iri is used to prove that the relationship between the minimum flow problem and the Hamiltonian path problem in a (directed) network, is not rigorous. A new model... A negative example shows that the model given by Mason Iri is used to prove that the relationship between the minimum flow problem and the Hamiltonian path problem in a (directed) network, is not rigorous. A new model called minimum spanning flow in a network is established to revise the old one. It is proved that the problem of determining whether there is a Hamiltonian path from a specified vertex s to another t on a given digraph can be reducible at polynomial time to the problem of constructing a minimum spanning flow in a two-terminal extended network s,t , with the unit capacity for all arcs. 展开更多
关键词 graph theory Hamiltonian path spanning flow
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k-Factors and Spanning Subgraph in Graphs
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作者 WANG Zhi-guo ZHANG Yi 《Chinese Quarterly Journal of Mathematics》 CSCD 北大核心 2006年第1期143-147,共5页
In this paper, we discussed k-factors and spanning subgraph, and propose a conjecture which will lead to a series of important conclusion.
关键词 K-FACTOR 2-connected graph spanning subgraph
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On the Decay Number of a Graph
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作者 LIDe-ming 《Chinese Quarterly Journal of Mathematics》 CSCD 北大核心 2005年第2期121-127,共7页
The decay number of a connected graph is defined to be the minimum number of the components of the cotree of the graph. Upper bounds of the decay numbers of graphs are obtained according to their edge connectivities. ... The decay number of a connected graph is defined to be the minimum number of the components of the cotree of the graph. Upper bounds of the decay numbers of graphs are obtained according to their edge connectivities. All the bounds in this paper are tight.Moreover, for each integer k between one and the upper bound, there are infinitely many graphs with the decay number k. 展开更多
关键词 decay number edge connectivity BOUND
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The Spatial Equivalence Between Wavelet Decomposition and Phase Space Embedding of EEG
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作者 YOU Rong-yi, HUANG Xiao-jing 《Chinese Journal of Biomedical Engineering(English Edition)》 2008年第3期101-105,共5页
Using both the wavelet decomposition and the phase space embedding, the phase trajectories of electroencephalogram (EEG) is described. It is illustrated based on the present work,that is,the wavelet decomposition of E... Using both the wavelet decomposition and the phase space embedding, the phase trajectories of electroencephalogram (EEG) is described. It is illustrated based on the present work,that is,the wavelet decomposition of EEG is essentially a projection of EEG chaotic attractor onto the wavelet space opened by wavelet filter vectors, which is in correspondence with the phase space embedding of the same EEG. In other words, wavelet decomposition and phase space embedding are equivalent in methodology. Our experimental results show that in both the wavelet space and the embedded space the structure of phase trajectory of EEG is similar to each other. These results demonstrate that wavelet decomposition is effective on characterizing EEG time series. 展开更多
关键词 electroencephalogram (EEG) wavelet decomposition embedded space EQUIVALENCE
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The Application of Schema Theory to English Reading Teaching in Junior High School
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作者 LI Jian-ping ZANG Li-sha 《Sino-US English Teaching》 2016年第1期14-21,共8页
Reading is an effective means to cultivate junior high school students' comprehensive ability of using English and plays an important role in English study. Schema theory is a scientific reading theory advocated by m... Reading is an effective means to cultivate junior high school students' comprehensive ability of using English and plays an important role in English study. Schema theory is a scientific reading theory advocated by modern teaching, and it regards the reading comprehension as a process that readers' knowledge and skills interact with the information in the reading material. In this paper, a questionnaire is conducted to reveal the fact that students lack schemata in reading and then a proposal that language schema, content schema, and form schema be integrated to activate students' existing schemata in the process of reading is put forward 展开更多
关键词 schema theory English reading teaching junior high school
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Graph-Theoretic Approach to Network Analysis
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作者 Nabil Hassan 《Computer Technology and Application》 2013年第12期625-634,共10页
Networks are a class of general systems represented by becomes a weighted graph visualizing the constraints imposed their UC-structure. Suppressing the nature of elements the network by interconnections rather than th... Networks are a class of general systems represented by becomes a weighted graph visualizing the constraints imposed their UC-structure. Suppressing the nature of elements the network by interconnections rather than the elements themselves. These constraints follow generalized Kirchhoff's laws derived from physical constraints. Once we have a graph; then the working environment becomes the graph-theory. An algorithm derived from graph theory is developed within the paper in order to analyze general networks. The algorithm is based on computing all the spanning trees in the graph G with an associated weight. This weight is the product ofadmittance's of the edges forming the spanning tree. In the first phase this algorithm computes a depth first spanning tree together with its cotree. Both are used as parents for controlled generation of off-springs. The control is represented in selecting the off-springs that were not generated previously. While the generation of off-springs, is based on replacement of one or more tree edges by cycle edges corresponding to cotree edges. The algorithm can generate a frequency domain analysis of the network. 展开更多
关键词 UC-structure NETWORK spanning tree depth-first search spanning trees generation algorithm.
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A Graph-theoretic Analysis of Stressors Confronting Giant Panda Habitat across Minshan Mountain Region,China 被引量:1
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作者 肖燚 欧阳志云 +2 位作者 赵景柱 黄宝荣 朱春全 《Journal of Resources and Ecology》 CSCD 2010年第4期339-344,共6页
岷山地区位于四川盆地西北部,是我国生物多样性保护的优先地区,还是保护大熊猫的关键区域。本文以社会-经济-自然复合生态系统为基础,运用图论分析法研究了岷山地区影响大熊猫生境的人类活动方式,以及这些影响因子相互的关系。研究表明... 岷山地区位于四川盆地西北部,是我国生物多样性保护的优先地区,还是保护大熊猫的关键区域。本文以社会-经济-自然复合生态系统为基础,运用图论分析法研究了岷山地区影响大熊猫生境的人类活动方式,以及这些影响因子相互的关系。研究表明:影响大熊猫生境的人类活动的66对组合中,47.0%的因子间存在直接的联系,其中89.2%的影响具有增大效应。这说明人类活动对大熊猫生境的影响具有协同增大效应,并占主导地位。旅游景点开发、公路建设、采矿、高压电线、农业开发、放牧、薪柴采集这些影响因子存在强连通性,它们会将其他人类活动对大熊猫生境的影响放大,加剧对大熊猫生境的不利影响,表明它们是影响岷山地区大熊猫生境的主导人类活动。要想有效地保护岷山地区的大熊猫生境,就必须对这些主导人类活动进行有效的控制。本研究还表明图论分析法有助于明确影响熊猫生境的主导和关键因子,它能为制定有效的大熊猫保护策略提供科学依据。 展开更多
关键词 giant panda habitat anthropogenic stressors graph-theoretic analysis Minshan
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Axiomatization of Special Relativity in First Order Logic
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作者 罗懿晨 陈磊 +2 位作者 何宛亭 马永革 张昕禹 《Communications in Theoretical Physics》 SCIE CAS CSCD 2016年第7期19-28,共10页
The axiomatization of physical theories is a fundamental issue of science. The first-order axiomatic system SpecR el for special relativity proposed recently by Andr′eka et al. is not enough to explain all the main r... The axiomatization of physical theories is a fundamental issue of science. The first-order axiomatic system SpecR el for special relativity proposed recently by Andr′eka et al. is not enough to explain all the main results in the theory, including the twin paradox and energy-mass relation. In this paper, from a four-dimensional spacetime perspective, we introduce the concepts of world-line, proper time and four-momentum to our axiomatic system SpecR el^+. Then we introduce an axiom of mass(Ax Mass) and take four-momentum conservation as an axiom(Ax CFM)in SpecR el^+. It turns out that the twin paradox and energy-mass relation can be derived from SpecR el+logically. Hence,as an extension of SpecR el, SpecR el^+is a suitable first-order axiomatic system to describe the kinematics and dynamics of special relativity. 展开更多
关键词 special relativity first-order logic axiomatization
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