The full wave FDTD method was used to analyze the Hilbert and H fractal curves antennas. The computational results of the input impedance of Hilbert fractal antenna are in good agreement with the experiments in the do...The full wave FDTD method was used to analyze the Hilbert and H fractal curves antennas. The computational results of the input impedance of Hilbert fractal antenna are in good agreement with the experiments in the documents. The results also show that the self-similarity of the fractal structure leads to the multiplicity of resonances over some predetermined operating bandwidths of the antenna. Fractal geometries of Hilbert and H curves can be implemented to miniaturize the antenna, too. The results also show that the higher order fractal antenna leads to the more efficient reduction of the antenna size than the lower order one. Furthermore, the far field patterns remain almost the same as those of the dipole at their own resonant frequencies.展开更多
This paper describes a novel method of online composite shape recognition interms of the relevance feedback technology to capture a user's intentions incrementally, and adynamic user modeling method to adapt to va...This paper describes a novel method of online composite shape recognition interms of the relevance feedback technology to capture a user's intentions incrementally, and adynamic user modeling method to adapt to various users' styles. First, the relevance feedback isadapted to refine the recognition results and reduce the ambiguity incrementally based on theestablishment of a feature-based vector model of a user's sketches. Secondly, a dynamic usermodeling is introduced to model the user's sketching habits based on recording and analyzinghistorical information incrementally. A model-based matching strategy is also employed in the methodto recognize sketches dynamically. Experiments prove that the proposed method is both effective andefficient.展开更多
关于这个话题,我们从两个方面来谈。什么是PDCA？近些年来,各家企业为完成企业任务目标,在执行前应对会影响任务目标的相关因素进行分析和计划,确定计划后开始执行,执行的结果要和目标进行比对验证,对总结检查的结果进行处理,成功的经...关于这个话题,我们从两个方面来谈。什么是PDCA？近些年来,各家企业为完成企业任务目标,在执行前应对会影响任务目标的相关因素进行分析和计划,确定计划后开始执行,执行的结果要和目标进行比对验证,对总结检查的结果进行处理,成功的经验加以肯定并适当推广、流程化、标准化;失败的教训加以总结,未解决的问题放到下一个循环里。这就是＂计划-执行-检核-改善＂的PDCA （Plan Do Check Action）管理循环,如图1所示。展开更多
Based on Fermat’s principle, two-point ray tracing method was studied in three-dimensional structure. By means of first order Taylor’s incomplete series expansion (i.e. no expansion to the length of the ray), a symm...Based on Fermat’s principle, two-point ray tracing method was studied in three-dimensional structure. By means of first order Taylor’s incomplete series expansion (i.e. no expansion to the length of the ray), a symmetry block tridiagonal matrix equation set was deduced. Further, the positive definiteness of coefficient matrix was discussed, and the positive definiteness was accurately proved in a mathematical way. It assured that the algorithm was well-posed. Associated with iterative method, the solution to ray tracing can be got through step-by-step linearized iteration of the nonlinear problem. An algorithm of the whole path iterative ray tracing method in three-dimensional velocity structure was obtained. This method shows a clear and simple as well as explicit computation formula, which makes ray tracing computation easily applicable in practice. The correction vector is obtained through finding the solution to the positive definite block tridiagonal equation set, which ensures the method is robust convergence. This study offers a new kind of feasible and efficient ray tracing method for three dimensional seismic migration and tomography. Meanwhile, it also provides the prerequisite guarantee to design a fast algorithm.展开更多
A hierarchical non-linear method for image registration was presented, which integrates image segmentation and registration under a variational framework. An improved deformable model is used to simultaneously segment...A hierarchical non-linear method for image registration was presented, which integrates image segmentation and registration under a variational framework. An improved deformable model is used to simultaneously segment and register feature from multiple images. The objects in the image pair are segmented by evolving a single contour and meanwhile the parameters of affine registration transformation are found out. After that, a contour-constrained elastic registration is applied to register the images correctly. The experimental results indicate that the proposed approach is effective to segment and register medical images.展开更多
Road horizontal alignment contains three elements: straight line,circular arc,and clothoid.In AutoCAD,clothoid can only be fitted by polyline or spline,and the graphics which are separated from the road data are indep...Road horizontal alignment contains three elements: straight line,circular arc,and clothoid.In AutoCAD,clothoid can only be fitted by polyline or spline,and the graphics which are separated from the road data are independent of each other.Therefore,it is necessary to develop a new curve for road horizontal alignment.Firstly,the differential approximation and series integration methods for clothoid were discussed.Secondly,the geometric formulae for road line which contain the three elements were derived as a whole.Then,the advantages and feasibility of customizing a road line class,which was derived from the curve base class,were analyzed based on ObjectARX(AutoCAD Runtime eXtension) techniques.Finally,the data structure and operations for the road line class were stressed.The experimental results show that the road line can integrate the road elements,graphics and data to implement the graphics-oriented design,which can be widely used in road alignment design.展开更多
This paper deals withthe automatic connection of contourlines extracted from a scanned browngeographical map. For the variety oftopographical elements contained on amap, the factors causing the interrup-tion of contou...This paper deals withthe automatic connection of contourlines extracted from a scanned browngeographical map. For the variety oftopographical elements contained on amap, the factors causing the interrup-tion of contour line are also multiform,which make the connection task verydifficult. On the basis of separatingthose elements always making the con-tours break and regarding them as ref-erent layers, a layering-based methodis presented. The purpose is to takeinto account property information (likeinclination and configuration) of con-tour lines when they come across otherdifferent symbols, such as gully, cliff,dry land and elevation annotation etc.In this paper, the authors propose thatit should be far more effective and di-rect to adopt different algorithmic op-erators to different factors than usingsingle one operator to all.展开更多
Moving ships produce a set of waves of "V' pattern on the ocean. These waves can often be seen by Synthetic Aperture Radar (SAR). The detection of these wakes can provide important information for surveillanc...Moving ships produce a set of waves of "V' pattern on the ocean. These waves can often be seen by Synthetic Aperture Radar (SAR). The detection of these wakes can provide important information for surveillance of shipping, such as ship traveling direction and speed. A novel approach to the detection of ship wakes in SAR images based on frequency domain is provided in this letter. Compared with traditional Radon-based approaches, computation is reduced by 20%-40% without losing nearly any of detection performance. The testing results using real data and simulation of synthetic SAR images test the algorithm's feasibility and robustness.展开更多
By truncating the Painleve expansion at the constant level term,the Hirota bilinear form is obtainedfor a (3+1)-dimensional variable-coefficient Kadomtsev-Petviashvili equation.Based on its bilinear form,solitary-wave...By truncating the Painleve expansion at the constant level term,the Hirota bilinear form is obtainedfor a (3+1)-dimensional variable-coefficient Kadomtsev-Petviashvili equation.Based on its bilinear form,solitary-wavesolutions are constructed via the ε-expansion method and the corresponding graphical analysis is given.Furthermore,the exact solution in the Wronskian form is presented and proved by direct substitution into the bilinear equation.展开更多
文摘The full wave FDTD method was used to analyze the Hilbert and H fractal curves antennas. The computational results of the input impedance of Hilbert fractal antenna are in good agreement with the experiments in the documents. The results also show that the self-similarity of the fractal structure leads to the multiplicity of resonances over some predetermined operating bandwidths of the antenna. Fractal geometries of Hilbert and H curves can be implemented to miniaturize the antenna, too. The results also show that the higher order fractal antenna leads to the more efficient reduction of the antenna size than the lower order one. Furthermore, the far field patterns remain almost the same as those of the dipole at their own resonant frequencies.
文摘This paper describes a novel method of online composite shape recognition interms of the relevance feedback technology to capture a user's intentions incrementally, and adynamic user modeling method to adapt to various users' styles. First, the relevance feedback isadapted to refine the recognition results and reduce the ambiguity incrementally based on theestablishment of a feature-based vector model of a user's sketches. Secondly, a dynamic usermodeling is introduced to model the user's sketching habits based on recording and analyzinghistorical information incrementally. A model-based matching strategy is also employed in the methodto recognize sketches dynamically. Experiments prove that the proposed method is both effective andefficient.
文摘关于这个话题,我们从两个方面来谈。什么是PDCA？近些年来,各家企业为完成企业任务目标,在执行前应对会影响任务目标的相关因素进行分析和计划,确定计划后开始执行,执行的结果要和目标进行比对验证,对总结检查的结果进行处理,成功的经验加以肯定并适当推广、流程化、标准化;失败的教训加以总结,未解决的问题放到下一个循环里。这就是＂计划-执行-检核-改善＂的PDCA （Plan Do Check Action）管理循环,如图1所示。
基金Project(40674071) supported by the National Natural Science Foundation of Chinaproject(KFAS2002-2003) supported by Korea Foundation for Advanced Studies
文摘Based on Fermat’s principle, two-point ray tracing method was studied in three-dimensional structure. By means of first order Taylor’s incomplete series expansion (i.e. no expansion to the length of the ray), a symmetry block tridiagonal matrix equation set was deduced. Further, the positive definiteness of coefficient matrix was discussed, and the positive definiteness was accurately proved in a mathematical way. It assured that the algorithm was well-posed. Associated with iterative method, the solution to ray tracing can be got through step-by-step linearized iteration of the nonlinear problem. An algorithm of the whole path iterative ray tracing method in three-dimensional velocity structure was obtained. This method shows a clear and simple as well as explicit computation formula, which makes ray tracing computation easily applicable in practice. The correction vector is obtained through finding the solution to the positive definite block tridiagonal equation set, which ensures the method is robust convergence. This study offers a new kind of feasible and efficient ray tracing method for three dimensional seismic migration and tomography. Meanwhile, it also provides the prerequisite guarantee to design a fast algorithm.
基金National Natural Science Foundation ofChina (No.60271033)
文摘A hierarchical non-linear method for image registration was presented, which integrates image segmentation and registration under a variational framework. An improved deformable model is used to simultaneously segment and register feature from multiple images. The objects in the image pair are segmented by evolving a single contour and meanwhile the parameters of affine registration transformation are found out. After that, a contour-constrained elastic registration is applied to register the images correctly. The experimental results indicate that the proposed approach is effective to segment and register medical images.
基金Project(51108049)supported by the National Natural Science Foundation of ChinaProject(kfj090207)supported by Open Fund of Key Laboratory of Road Structure and Material of Ministry of Transport(Changsha University of Science and Technology),China
文摘Road horizontal alignment contains three elements: straight line,circular arc,and clothoid.In AutoCAD,clothoid can only be fitted by polyline or spline,and the graphics which are separated from the road data are independent of each other.Therefore,it is necessary to develop a new curve for road horizontal alignment.Firstly,the differential approximation and series integration methods for clothoid were discussed.Secondly,the geometric formulae for road line which contain the three elements were derived as a whole.Then,the advantages and feasibility of customizing a road line class,which was derived from the curve base class,were analyzed based on ObjectARX(AutoCAD Runtime eXtension) techniques.Finally,the data structure and operations for the road line class were stressed.The experimental results show that the road line can integrate the road elements,graphics and data to implement the graphics-oriented design,which can be widely used in road alignment design.
基金the Scientific Research Foundation of Wuhan University (No. 40071071).
文摘This paper deals withthe automatic connection of contourlines extracted from a scanned browngeographical map. For the variety oftopographical elements contained on amap, the factors causing the interrup-tion of contour line are also multiform,which make the connection task verydifficult. On the basis of separatingthose elements always making the con-tours break and regarding them as ref-erent layers, a layering-based methodis presented. The purpose is to takeinto account property information (likeinclination and configuration) of con-tour lines when they come across otherdifferent symbols, such as gully, cliff,dry land and elevation annotation etc.In this paper, the authors propose thatit should be far more effective and di-rect to adopt different algorithmic op-erators to different factors than usingsingle one operator to all.
文摘Moving ships produce a set of waves of "V' pattern on the ocean. These waves can often be seen by Synthetic Aperture Radar (SAR). The detection of these wakes can provide important information for surveillance of shipping, such as ship traveling direction and speed. A novel approach to the detection of ship wakes in SAR images based on frequency domain is provided in this letter. Compared with traditional Radon-based approaches, computation is reduced by 20%-40% without losing nearly any of detection performance. The testing results using real data and simulation of synthetic SAR images test the algorithm's feasibility and robustness.
基金Supported by the National Natural Science Foundation of China under Grant No.60772023the Open Fund of the State Key Laboratory of Software Development Environment under Grant No.BUAA-SKLSDE-09KF-04+1 种基金Beijing University of Aeronautics and Astronautics,by the National Basic Research Program of China (973 Program) under Grant No.2005CB321901the Specialized Research Fund for the Doctoral Program of Higher Education under Grant Nos.20060006024 and 200800130006,the Ministry of Education
文摘By truncating the Painleve expansion at the constant level term,the Hirota bilinear form is obtainedfor a (3+1)-dimensional variable-coefficient Kadomtsev-Petviashvili equation.Based on its bilinear form,solitary-wavesolutions are constructed via the ε-expansion method and the corresponding graphical analysis is given.Furthermore,the exact solution in the Wronskian form is presented and proved by direct substitution into the bilinear equation.
