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灌溉用水管理多向图及其应用
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作者 朱景武 薛振德 《农田水利与小水电》 1990年第7期13-15,共3页
灌溉用水管理多向图把渠道供水能力、田间耗水强度、效益面积、灌水时间等因素融于一体,按照一定关系以曲线组绘成合轴相关图。通过该图既可初步设计渠道流量,选定灌溉面积,也可确定轮灌周期、轮灌面积等。该图查用方便,容易掌握,查算... 灌溉用水管理多向图把渠道供水能力、田间耗水强度、效益面积、灌水时间等因素融于一体,按照一定关系以曲线组绘成合轴相关图。通过该图既可初步设计渠道流量,选定灌溉面积,也可确定轮灌周期、轮灌面积等。该图查用方便,容易掌握,查算结果可靠。 展开更多
关键词 灌溉 用水管理 多向图
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Guide Rules for Electronic Atlas Project in China
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作者 REN Fu DU Qingyun 《Geo-Spatial Information Science》 2006年第1期71-75,共5页
Electronic atlas project (E-atlas project) plays a n important role in the procedure of popularizing maps and is diversifying its a pplication widely in China. Practice for E-atlas projects is a basic approach f or ac... Electronic atlas project (E-atlas project) plays a n important role in the procedure of popularizing maps and is diversifying its a pplication widely in China. Practice for E-atlas projects is a basic approach f or achieving public accessibility to national spatial data infrastructure (N SDI) and meets people’s inherent needs of updated maps. This paper provides a d escription and assessment of an integration of E-atlas projects, analyzes curre nt progress and characters of E-atlas project, summarizes basic guide rules, an d provides solution and interpretation. It depicts a conceptual framework of an authoring toolkit that is driven by application of E-atlas on the basis of succ essful instances. The toolkit which improves interactive interface, decreases op erational difficulties is developed in Visual C++ and used widely in China. 展开更多
关键词 electronic atlas project multimedia atlas electronic atlas
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Identification Method of Gas-Liquid Two-phase Flow Regime Based on Image Multi-feature Fusion and Support Vector Machine 被引量:6
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作者 周云龙 陈飞 孙斌 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2008年第6期832-840,共9页
The knowledge of flow regime is very important for quantifying the pressure drop, the stability and safety of two-phase flow systems. Based on image multi-feature fusion and support vector machine, a new method to ide... The knowledge of flow regime is very important for quantifying the pressure drop, the stability and safety of two-phase flow systems. Based on image multi-feature fusion and support vector machine, a new method to identify flow regime in two-phase flow was presented. Firstly, gas-liquid two-phase flow images including bub- bly flow, plug flow, slug flow, stratified flow, wavy flow, annular flow and mist flow were captured by digital high speed video systems in the horizontal tube. The image moment invariants and gray level co-occurrence matrix texture features were extracted using image processing techniques. To improve the performance of a multiple classifier system, the rough sets theory was used for reducing the inessential factors. Furthermore, the support vector machine was trained by using these eigenvectors to reduce the dimension as flow regime samples, and the flow regime intelligent identification was realized. The test results showed that image features which were reduced with the rough sets theory could excellently reflect the difference between seven typical flow regimes, and successful training the support vector machine could quickly and accurately identify seven typical flow regimes of gas-liquid two-phase flow in the horizontal tube. Image multi-feature fusion method provided a new way to identify the gas-liquid two-phase flow, and achieved higher identification ability than that of single characteristic. The overall identification accuracy was 100%, and an estimate of the image processing time was 8 ms for online flow regime identification. 展开更多
关键词 flow regime identification gas-liquid two-phase flow image processing multi-feature fusion support vector machine
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An Improved Directed Acyclic Graph Support Vector Machine
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作者 Adel RHUMA Syed Mohsen NAQVI Jonathon CHAMBERS 《Journal of Measurement Science and Instrumentation》 CAS 2011年第4期367-370,共4页
In this paper, we propose an improved Directed Acyclic Graph Support Vector Machine (DAGSVM) for multi-class classification. Compared with the traditional DAGSVM, the improved version has advantages that the structu... In this paper, we propose an improved Directed Acyclic Graph Support Vector Machine (DAGSVM) for multi-class classification. Compared with the traditional DAGSVM, the improved version has advantages that the structure of the directed acyclic graph is not chosen random and fixed, and it can be adaptive to be optimal according to the incoming testing samples, thus it has a good generalization performance. From experiments on six datasets, we can see that the proposed improved version of DAGSVM is better than the traditional one with respect to the accuracy rate. 展开更多
关键词 class classification directed acyclic graph support vector machine
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A Heuristic Approach to Fast NOVCA (Near Optimal Vertex Cover Algorithm)
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作者 Sanj aya Gajurel Roger Bielefeld 《Computer Technology and Application》 2014年第2期83-90,共8页
This paper describes an extremely fast polynomial time algorithm, the NOVCA (Near Optimal Vertex Cover Algorithm) that produces an optimal or near optimal vertex cover for any known undirected graph G (V, E). NOVC... This paper describes an extremely fast polynomial time algorithm, the NOVCA (Near Optimal Vertex Cover Algorithm) that produces an optimal or near optimal vertex cover for any known undirected graph G (V, E). NOVCA is based on the idea of(l) including the vertex having maximum degree in the vertex cover and (2) rendering the degree of a vertex to zero by including all its adjacent vertices. The three versions of algorithm, NOVCA-I, NOVCA-II, and NOVCA-random, have been developed. The results identifying bounds on the size of the minimum vertex cover as well as polynomial complexity of algorithm are given with experimental verification. Future research efforts will be directed at tuning the algorithm and providing proof for better approximation ratio with NOVCA compared to any available vertex cover algorithms. 展开更多
关键词 Vertex cover problem combinatorial problem NP-complete problem approximation algorithm OPTIMIZATION algorithms.
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灯笼图的奇优美标号 被引量:3
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作者 把丽娜 刘倩 +1 位作者 刘信生 姚兵 《数学的实践与认识》 北大核心 2017年第9期166-176,共11页
提出了灯笼图、多向灯笼图、复杂灯笼图,研究了它们的奇优美性,证明灯笼图是二分奇优美图、超级边魔幻图和超级反魔幻图.
关键词 简单灯笼 多向灯笼 复杂灯笼 二分奇优美标号
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THE LINEAR ARBORICITY OF COMPOSITION GRAPHS
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作者 WU Jianliang +2 位作者 LIU Guizhen Yuliang 《Journal of Systems Science & Complexity》 SCIE EI CSCD 2002年第4期372-375,共4页
The linear arboricity la(G) of a graph G is the minimum number of linear forests which partition the edges of G. Akiyama, Exoo and Harary conjectured that la(G) = [△(G)+1/2] for any regular graph G. In this paper, we... The linear arboricity la(G) of a graph G is the minimum number of linear forests which partition the edges of G. Akiyama, Exoo and Harary conjectured that la(G) = [△(G)+1/2] for any regular graph G. In this paper, we prove the conjecture for some composition graphs, in particular, for complete multipartite graphs. 展开更多
关键词 GRAPH composition of graphs linear arboricity complete multipartite graph.
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DETERMINATION OF THE DENSEST SUBGRAPH
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作者 DONGJinquan LIUYanpei 《Journal of Systems Science & Complexity》 SCIE EI CSCD 2004年第1期23-27,共5页
Define the density d(G) of a graph G as (ε(G))/(v(G)). A polynomialalgorithm for finding the densest subgraph of a graph is provided. Some results related to thedensity of the densest subgraph of a graph are obtained... Define the density d(G) of a graph G as (ε(G))/(v(G)). A polynomialalgorithm for finding the densest subgraph of a graph is provided. Some results related to thedensity of the densest subgraph of a graph are obtained as well. 展开更多
关键词 DENSITY ALGORITHM ORIENTATION computable
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Pfaffian graphs embedding on the torus 被引量:2
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作者 ZHANG LianZhu WANG Yan LU FuLiang 《Science China Mathematics》 SCIE 2013年第9期1957-1964,共8页
An orientation of a graph G with even number of vertices is Pfaffian if every even cycle C such that G-V(C) has a perfect matching has an odd number of edges directed in either direction of the cycle. The significance... An orientation of a graph G with even number of vertices is Pfaffian if every even cycle C such that G-V(C) has a perfect matching has an odd number of edges directed in either direction of the cycle. The significance of Pfaffian orientations stems from the fact that if a graph G has one, then the number of perfect matchings of G can be computed in polynomial time. There is a classical result of Kasteleyn that every planar graph has a Pfaffian orientation. Little proved an elegant characterization of bipartite graphs that admit a Pfaffian orientation. Robertson, Seymour and Thomas (1999) gave a polynomial-time recognition algorithm to test whether a bipartite graph is Pfaffian by a structural description of bipartite graphs. In this paper, we consider the Pfaffian property of graphs embedding on the orientable surface with genus one (i.e., the torus). Some sufficient conditions for Pfaffian graphs on the torus are obtained. Furthermore, we show that all quadrilateral tilings on the torus are Pfaffian if and only if they are not bipartite graphs. 展开更多
关键词 Pfaffian graph perfect matching crossing orientation
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A New Conception of Image Texture and Remote Sensing Image Segmentation Based on Markov Random Field 被引量:1
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作者 GONG Yan SHU Ning +2 位作者 LI Jili LIN Liqun LI Xue 《Geo-Spatial Information Science》 2010年第1期16-23,共8页
The texture analysis is often discussed in image processing domain, but most methods are limited within gray-level image or color image, and the present conception of texture is defined mainly based on gray-level imag... The texture analysis is often discussed in image processing domain, but most methods are limited within gray-level image or color image, and the present conception of texture is defined mainly based on gray-level image of single band. One of the essential characters of remote sensing image is multidimensional or even high-dimensional, and the traditional texture conception cannot contain enough information for these. Therefore, it is necessary to pursuit a proper texture definition based on remote sensing images, which is the first discussion in this paper. This paper describes the mapping model of spectral vector in two-dimensional image space using Markov random field (MRF), establishes a texture model of multiband remote sensing image based on MRF, and analyzes the calculations of Gibbs potential energy and Gibbs parameters. Further, this paper also analyzes the limitations of the traditional Gibbs model, prefers a new Gibbs model avoiding estimation of parameters, and presents a new texture segmentation algorithm for hy-perspectral remote sensing image later. 展开更多
关键词 hyperspectral multispectral MRF Gibbs model texture segmentation
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