检索结果-南通市图书馆

Seabed Classification Using BP Neural Network Based on GA

在线全文

学校读者我要写书评

暂无评论

Acta Oceanologica Sinica 2003年第4期22卷 523-531页

作者： Yang Fanlin1, Liu Jingnan2.1. GPS Engineering Research Center, wuhan university, wuhan 4.0079, China. 2. Presidential Secretariat, wuhan university, wuhan 4.0079, China wuhan Univ GPS Engn Res Ctr Wuhan 430079 Peoples R China

Side scan sonar imaging is one of the advanced methods for seabed study. In order to be utilized in other projects, such as ocean engineering, the image needs to be classified according to the distributions of different classes of seabed materials. In this paper, seabed image is classified according to BP neural network, and. Genetic Algorithm is adopted in train network in this paper. The feature vectors are average intensity, six statistics of texture and two dimensions of fractal. It considers not only the spatial correlation between different pixels, but also the terrain coarseness. The texture is denoted by the statistics of the co-occurrence matrix. Double Blanket algorithm is used to calculate dimension. Because a uniform fractal may not be sufficient to describe a seafloor, two dimensions are calculated respectively by the upper blanket and the lower blanket. However, in sonar image, fractal has directivity, i. e. there are different dimensions in different direction. Dimensions are different in acrosstrack and alongtrack, so the average of four directions is used to solve this problem. Finally, the real data verify the algorithm. In this paper, one hidden layer including six nodes is adopted. The BP network is rapidly and accurately convergent through GA. Correct classification rate is 92.5 % in the result.

关键词： BP network co-occurrence matrix fractal classification genetic algorithin

Analysis on the long term discharge of a catchment

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2000年第3期12卷 279-285页

作者： HONG Lin 1, TAKASE Keiji 2. SATO Koichi 2.(1. wuhan university of Hydraulic and Electric Engineering, wuhan 4.0072. China 2. Ehime university, Japan) wuhan university of Hydraulic and Electric Engineering Wuhan 430072 China Ehime university Japan

In this study, the characteristics of the long term discharge of a Terraced Paddy Field Catchment are studied. 2.Kind of Tank Models are proposed and used to simulate the discharge of the catchment. The characteristics of the model simulations of the discharge of the catchment are analyzed and compared with those of a forest catchment.

关键词： long term discharge model simulation terraced paddy field catchment

Second-order consensus in networks of dynamic agents with communication time-delays

在线全文

学校读者我要写书评

暂无评论

Journal of Systems Engineering and Electronics 2010年第1期21卷 88-94页

作者： Bo Yang1,2. Huajing Fang3, and Hua Wang4.1. School of Navigation, wuhan university of Technology, wuhan 4.0063, P. R. China 2. wuhan Second Ship Design and Research Institute, wuhan 4.0064. P. R. China 3. Department of Control Science and Engineering, Huazhong university of Science and Technology, wuhan 4.0074. P. R. China 4. Department of Aerospace and Mechanical Engineering, Boston university, Boston MA02.15, USA School of Navigation Wuhan University of Technology Wuhan 430063 P. R. China wuhan Second Ship Design and Research Institute Wuhan 430064 E R. China Department of Control Science and Engineering Huazhong University of Science and Technology Wuhan 430074 P. R. China Department of Aerospace and Mechanical Engineering Boston University Boston MA02215 USA

This paper proposes second-order consensus protocols with time-delays and gives the measure of the robustness of the protocols to the time-delay existing in the network of agents with second-order dynamics. By employing a frequency domain method, it is proven that the information states and their time derivatives of all the agents in the network achieve consensus asymptotically, respectively, for appropriate communication timedelay if the topology of weighted network is connected. Particularly, a tight upper bound on the communication time-delay that can be tolerated in the dynamic network is found. The consensus protocols are distributed in the sense that each agent only needs information from its neighboring agents, which reduces the complexity of connections between neighboring agents significantly. Numerical simulation results are provided to demonstrate the effectiveness and the sharpness of the theoretical results for second-order consensus in networks in the presence of communication time-delays.

关键词： second-order consensus protocols dynamic networks algebraic graph theory frequency domain analysis com-munication constraints.

HCWCI/Carbon Steel Bimetal Liner by Liquid-Liquid Compound Lost Foam Casting

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2012年第10期19卷 13-19页

作者： XIAO Xiao-feng1,2. YE Sheng-ping2. YIN Wei-xin3, XUE Qiong4.(1. School of Mechanical Engineering and Automation, wuhan Textile university, wuhan 4.0073, Hubei, China 2. State Key Laboratory of Material Processing and Die and Mould Technology, Huazhong university of Science and Technology, wuhan 4.0074. Hubei, China 3. wuhan Zhike Abrasive-Resistant Material Science and Technology Development Co Ltd, wuhan 4.0073, Hubei, China 4. College of Science, wuhan university of Technology, wuhan 4.0079, Hubei, China) [a] School of Mechanical Engineering and Automation Wuhan Textile University Wuhan 430073 Hubei China [b] State Key Laboratory of Material Processing and Die and Mould Technology Huazhong University of Science and Technology Wuhan 430074 Hubei China [c] wuhan Zhike Abrasive-Resistant Material Science and Technology Development Co Ltd Wuhan 430073 Hubei China [d] College of Science Wuhan University of Technology Wuhan 430079 Hubei China

Impact, friction and corrosion from the grinding balls and the grinding medium during the mineral processing result in liner breakage. Liner, made from Hadfield steel or alloyed steel, could not have served in wet grinding environment for more than ten months. Composite liner, made from HCWCI (high Cr white cast iron) and carbon steel, has been developed successfully with liquid-liquid composing process based on LFC (lost foam casting). The microstructure of composite was analyzed with optical microscope, SEM (scanning electron microscope)/EDX energy-dispersive X-ray and XRD (X-ray diffraction). According to micrograph, the combination region of two metals was staggered like dogtooth, no mixtures occurred between two liquid metals, and its interface presented excellent metallurgical bonding state. The results of mechanical property test show that, the hardness of HRC, the fracture toughness, and the bending strength are more than 61, 16.5 J/cm2.and 1 600 MPa, respectively. Comparison between liners made from bimetal composite and alloyed steel has also been investigated in industrial hematite ball mill. The results of eight months test in wet grinding environment prove that the service life of bimetal composite liner is three times as long as that of one made from alloyed steel.

关键词： composite liner bimetal liquid-liquid compound composite interface lost foam casting high Cr white cast iron

Evaluation Method of Web Site Structure Based on Web Structure Mining

在线全文

学校读者我要写书评

暂无评论

wuhan university Journal of Natural Sciences 2003年第3A期8卷 791-796页

作者： Li Jun\|e 1 , Zhou Dong\|ru 2.1. Computer Center,wuhan university, wuhan {4. Hubei, China 2. School of Computer,wuhan university, wuhan {4. Hubei,China wuhan university Computer Center Wuhan Hubei China (GRID:grid.49470.3e) (ISNI:***) wuhan university School of Computer Wuhan Hubei China (GRID:grid.49470.3e) (ISNI:***)

The structure of Web site became more complex than before. During the design period of a Web site, the lack of model and method results in improper Web structure, which depend on the designer's experience. From the point of view of software engineering, every period in the software life must be evaluated before starting the next period's work. It is very important and essential to search relevant methods for evaluating Web structure before the site is completed. In this work, after studying the related work about the Web structure mining and analyzing the major structure mining methods (Page\|rank and Hub/Authority), a method based on the Page\|rank for Web structure evaluation in design stage is proposed. A Web structure modeling language WSML is designed, and the implement strategies for evaluating system of the Web site structure are given out. Web structure mining has being used mainly in search engines before. It is the first time to employ the Web structure mining technology to evaluate a Web structure in the design period of a Web site. It contributes to the formalization of the design documents for Web site and the improving of software engineering for large scale Web site, and the evaluating system is a practical tool for Web site construction.

关键词： web structure mining page\|rank web structure evaluation modeling language for web structure

Minimal systems of generators for central division algebra and semi-simple algebra

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 1998年第21期43卷 1777-1780页

作者： QIU Qizhang 1 and SUN Ling 2.1. Department of Mathematics, wuhan university, wuhan {4. China 2. Department of Information science, wuhan university, wuhan {4. China. Department of Mathematics Wuhan University Wuhan China Department of Information science Wuhan University Wuhan China

Suppose that F is a field of characteristic zero and (ⅰ) D is a finite-dimensional central division algabra over F; (ⅱ) A is a finite-dimensional semi-simple algabra over F. It is proved that as F-algebras, D and A ... 详细信息

关键词： central division algebra semi-simple algebra generator minimal system of generators.

Experimental study of ore gabbro liquid immiscibility

在线全文

学校读者我要写书评

暂无评论

Science China Earth Sciences 2005年第4期48卷 496-505页

作者： SANG Zunan1,2. XIA Bin1, ZHOU Yongsheng3 & JIN Zhenmin4.1. Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 51064., China 2. wuhan university, wuhan {2. China 3. Institute of Geology, China Seismological Bureau, Beijing 10002., China 4. Faculty of Earth Sciences, China university of Geosciences, wuhan 4.0074. China 1. Guangzhou Institute of Geochemistry Chinese Academy of Sciences 510640 Guangzhou China 2. wuhan university 430072 Wuhan China 3. Institute of Geology China Seismological Bureau 100029 Beijing China 4. Faculty of Earth Sciences China University of Geosciences 430074 Wuhan China

In this paper, the authors present the results of a preliminary experimental study on partial melting of fine-grained gabbro, Panzhihua, Sichuan Province, China. Experiments were conducted under (confining) pressure ranging from 4.0 to 500 MPa and temperature of 900— 12.0℃. The results show that the initial melt is distributed along grain boundaries and triple junctions. Liquid immiscibility phenomena are noted in the melt with two compositional different melt phases, i.e. matrix and sphere phases. The matrix phase is relatively rich in Si, Al and K, and is depleted in Mg, Fe, Ca, Na and Ti, whereas the sphere phase shows opposite trends. The calculation of the melt free energy indicates that the liquid immiscibility is governed by the rule of thermodynamics, as the liquid immiscibility would result in the decrease in free energy of the melt system. The field relationships suggest that the liquid immiscibility may have played an important role in the generation of ore magma of Panzhihua V-Ti magnetite ore deposit. This study thus provides experimental constraints on the mechanism of the formation of V-Ti magnetite deposite.

关键词： partial melting, experimental study, gabbro, liquid immiscibility, ore formation mechanism.

Preparation and Characterization of Chitosan/Carboxymethylated Konjac Glucomannan Blend Films

在线全文

学校读者我要写书评

暂无评论

wuhan university Journal of Natural Sciences 2002年第1期7卷 107-112页

作者： Zheng Hua 1 , Du Yu-min 2.1. Department of Chemical Engineering, wuhan university of Technology, wuhan 4.0070, Hubei, China 2. College of Chemistry and Molecular Sciences, wuhan university, wuhan 4.0072. Hubei, China wuhan university of Technology Department of Chemical Engineering Wuhan Hubei China (GRID:grid.162110.5) (ISNI:***) wuhan university College of Chemistry and Molecular Sciences Wuhan Hubei China (GRID:grid.49470.3e) (ISNI:***)

In order to improve the mechanical and water swelling properties of the chitosan (CS) film, a series of transparent films were prepared by blending 2.(weight) chitosan acetic acid solution with 1.5%(weight) carboxymethylated konjac glucomannan (CMKGM) aqueous solution according to predetermined ratio and drying at 30°C. The morphological structure, miscibility, thermal stability, mechanical properies, and swelling capacity of the blend films were studied by infrared (IR), X-ray diffraction (XRD), differential thermal analysis (DTA), scanning electron micrograph (SEM), and measurements of the mechanical properties and swelling properties. The results demonstrated that there was strong interaction and good miscibility between CS and CMKGM resulted from intermolecular hydrogen bonding and electrostatic force. The mechanical properties in dry state and wet state, thermostability, and water swelling properties of the blend films were obviously improved. The best values of the tensile strength in the dry and wet state achieved 89 MPa and 4. MPa, respectively, when the CMKGM content was 30%(weight). The CS/ CMKGM blend films provided promising biomedical applications.

关键词： Key words chitosan carboxymethylated konjac glucomannan blend films structure characterization

Electronic Structure of Doped Trans-Polyacetylene

在线全文

学校读者我要写书评

暂无评论

wuhan university Journal of Natural Sciences 2002年第1期7卷 51-53页

作者： Ren Da-zhi 1,2. Zhuang Wei 2. Wang Jun 2.1. wuhan {4. Journals Press,wuhan 4.0072.Hubei,China 2. School of Physics and Technology, wuhan {4., wuhan 4.0072.Hubei,China wuhan university Journals Press Wuhan Hubei China (GRID:grid.49470.3e) (ISNI:***) wuhan university School of Physics and Technology Wuhan Hubei China (GRID:grid.49470.3e) (ISNI:***) wuhan university School of Physics and Technology Wuhan Hubei China (GRID:grid.49470.3e) (ISNI:***)

The behavior of electronic structures of doped trans-polyacetylene is revealed by a simple method. (C2.H2.)+n is used to simulate p-type doped trans-polyacetylene at various doping concentrations. The electronic structure is calculated, by CNDO/2.method. These calculations show that at low doping level, the decrease of electronic energy compensates the increase of elastic energy, thus the bond alternation exists, and the charge carriers are solitons. When doping level is high, the increase of elastic energy is larger than the decrease, of electronic energy, the bond alternation disappears, solitons no longer exist, and polyacetylene is in a metalic state.

关键词： trans polyacetylene CNDO/2 electronic structure doped