A new authentication algorithm for grid identity trusted computing unlimited by hardware is presented;the trusted root is made as an image data.The grid entity is trusted in the soft platform when its feature of image...A new authentication algorithm for grid identity trusted computing unlimited by hardware is presented;the trusted root is made as an image data.The grid entity is trusted in the soft platform when its feature of image root is entirely matched with that from the other entities＇ feature database in a scale space process.To recognize and detect the stable image root feature,the non-homogeneous linear expandable scale space is proposed.Focusing on relations between the scale parameter of the inhomogeneous Gaussian function terms and the space evolution of thermal diffusion homogeneous equations,three space evolution operators are constructed to exact and mark the feature from image root.Analysis and verification are carried on the new scale space,operators and the core of making decisions for grid entities certifications.展开更多
目前基于正交时频空(orthogonal time frequency space,OTFS)的雷达目标参数估计算法以在网估计为主,但在网估计算法无法有效应对现实应用中的离网现象。同时,现有离网估计算法的目标参数估计性能受建模误差的限制,也难以确保雷达系统...目前基于正交时频空(orthogonal time frequency space,OTFS)的雷达目标参数估计算法以在网估计为主,但在网估计算法无法有效应对现实应用中的离网现象。同时,现有离网估计算法的目标参数估计性能受建模误差的限制,也难以确保雷达系统在复杂环境下的有效应用。针对以上问题,提出了一种基于OTFS调制的动态稀疏贝叶斯(dynamic-sparse Bayesian learning,dynamic-SBL)算法。该算法在稀疏贝叶斯学习框架下引入动态虚拟网格,通过不断更新调整网格参数降低建模误差,提升目标参数估计性能。同时利用OTFS雷达信道特有的稀疏性对网格参数进行选择性局部更新,以降低算法的复杂度。仿真结果表明,所提算法估计的目标归一化时延和多普勒频率的均方误差较小,目标参数的估计性能优于传统离网估计方法的。该算法在实际雷达系统中具有较大应用潜力。展开更多
In wind power generation system the grid-connected inverter is an important section for energy conversion and transmission, of which the performance has a direct influence on the entire wind power generation system. T...In wind power generation system the grid-connected inverter is an important section for energy conversion and transmission, of which the performance has a direct influence on the entire wind power generation system. The mathematical model of the grid-connected inverter is deduced firstly. Then, the space vector pulse width modulation （SVPWM） is analyzed. The power factor can be controlled close to unity, leading or lagging, which is realized based on H-type current controller and grid voltage vector-oriented control. The control strategy is verified by the simulation and experimental results with a good sinusoidal current, a small harmonic component and a fast dynamic response.展开更多
Based on the desilting research of one scheduling project in the southwest of China, the method of setting grid desilting gallery before the desilting tunnel is put forward to expand the scope of the scouring funnel b...Based on the desilting research of one scheduling project in the southwest of China, the method of setting grid desilting gallery before the desilting tunnel is put forward to expand the scope of the scouring funnel before the dam and solve the problem of sediment deposition at the power station water intake. The experimental results show that, in the design of a grid desilting gallery, the width of the grid gallery should not be smaller than that of the desiring bottom intake, the size of the grid orifice should be in the range of 1.5 m--2.0 m along the flow direction, and the grid spacing should be 3--5 times the size of the grid orifice. The discharging ability of the desilting bottom intake will decrease after the grid desilting gallery is added. The average of the decrease rates is about 5%-10%. The scouring funnel draws in the longitudinal direction before the dam obviously after the construction of the grid desilting gallery.展开更多
The Sensitivity Encoding (SENSE) parallel reconstruction scheme for magnetic resonance imaging (MRI) is implemented with non-cartesian sampled k-space trajectories in this paper. SENSE has the special capability to re...The Sensitivity Encoding (SENSE) parallel reconstruction scheme for magnetic resonance imaging (MRI) is implemented with non-cartesian sampled k-space trajectories in this paper. SENSE has the special capability to reduce the scanning time for MRI experiments while maintaining the image resolution with under-sampling data sets. In this manner, it has become an increasingly popular technique for multiple MRI data acquisition and image reconstruction schemes. The gridding algorithm is also implemented with SENSE due to its ability in evaluating forward and adjoin operator with non-cartesian sampled data. In this paper, the sensitivity map profile, field map information and the spiral k-space data collected from an array of receiver coils are used to reconstruct unaliased images from under-sampled data. The performance of SENSE with real data set identifies the computational issues to be improved for researched.展开更多
地理信息系统(Geographical Information System,简称GIS)是处理地理空间数据的信息系统,它集现实世界中对象的空间位置和人文经济信息的管理于一体.全面阐述了如何将Arcinfo软件的Grid模块应用到水利,进行洪水预报系统的开发.将地理信...地理信息系统(Geographical Information System,简称GIS)是处理地理空间数据的信息系统,它集现实世界中对象的空间位置和人文经济信息的管理于一体.全面阐述了如何将Arcinfo软件的Grid模块应用到水利,进行洪水预报系统的开发.将地理信息系统与Grid模块的水文表面分析工具相结合,形成直观的流域环境显示,再通过计算、统计、分析,可获得精确的水文因子数据,为洪水预报系统提供快速、准确的实时流域参数.展开更多
基金Foundation item: Supported by the National Natural Science Foundation (61070151,60903203,61103246)the Natural Science Foundation of Fujian Province (2010J01353)+1 种基金the Xiamen University of Technology Scientific Research Foundation (YKJ11024R)Xiamen Scientific Research Foundation (3502Z20123037)
文摘A new authentication algorithm for grid identity trusted computing unlimited by hardware is presented;the trusted root is made as an image data.The grid entity is trusted in the soft platform when its feature of image root is entirely matched with that from the other entities＇ feature database in a scale space process.To recognize and detect the stable image root feature,the non-homogeneous linear expandable scale space is proposed.Focusing on relations between the scale parameter of the inhomogeneous Gaussian function terms and the space evolution of thermal diffusion homogeneous equations,three space evolution operators are constructed to exact and mark the feature from image root.Analysis and verification are carried on the new scale space,operators and the core of making decisions for grid entities certifications.
文摘目前基于正交时频空(orthogonal time frequency space,OTFS)的雷达目标参数估计算法以在网估计为主,但在网估计算法无法有效应对现实应用中的离网现象。同时,现有离网估计算法的目标参数估计性能受建模误差的限制,也难以确保雷达系统在复杂环境下的有效应用。针对以上问题,提出了一种基于OTFS调制的动态稀疏贝叶斯(dynamic-sparse Bayesian learning,dynamic-SBL)算法。该算法在稀疏贝叶斯学习框架下引入动态虚拟网格,通过不断更新调整网格参数降低建模误差,提升目标参数估计性能。同时利用OTFS雷达信道特有的稀疏性对网格参数进行选择性局部更新,以降低算法的复杂度。仿真结果表明,所提算法估计的目标归一化时延和多普勒频率的均方误差较小,目标参数的估计性能优于传统离网估计方法的。该算法在实际雷达系统中具有较大应用潜力。
基金supported by Delta Power Electronic Science and Education Development in 2007 (Grant No.DRES2007002)
文摘In wind power generation system the grid-connected inverter is an important section for energy conversion and transmission, of which the performance has a direct influence on the entire wind power generation system. The mathematical model of the grid-connected inverter is deduced firstly. Then, the space vector pulse width modulation （SVPWM） is analyzed. The power factor can be controlled close to unity, leading or lagging, which is realized based on H-type current controller and grid voltage vector-oriented control. The control strategy is verified by the simulation and experimental results with a good sinusoidal current, a small harmonic component and a fast dynamic response.
基金Supported by National Key Technology R&D Program during the11th Five-Year Plan Period of China (No.2006BAD11B03)
文摘Based on the desilting research of one scheduling project in the southwest of China, the method of setting grid desilting gallery before the desilting tunnel is put forward to expand the scope of the scouring funnel before the dam and solve the problem of sediment deposition at the power station water intake. The experimental results show that, in the design of a grid desilting gallery, the width of the grid gallery should not be smaller than that of the desiring bottom intake, the size of the grid orifice should be in the range of 1.5 m--2.0 m along the flow direction, and the grid spacing should be 3--5 times the size of the grid orifice. The discharging ability of the desilting bottom intake will decrease after the grid desilting gallery is added. The average of the decrease rates is about 5%-10%. The scouring funnel draws in the longitudinal direction before the dam obviously after the construction of the grid desilting gallery.
文摘The Sensitivity Encoding (SENSE) parallel reconstruction scheme for magnetic resonance imaging (MRI) is implemented with non-cartesian sampled k-space trajectories in this paper. SENSE has the special capability to reduce the scanning time for MRI experiments while maintaining the image resolution with under-sampling data sets. In this manner, it has become an increasingly popular technique for multiple MRI data acquisition and image reconstruction schemes. The gridding algorithm is also implemented with SENSE due to its ability in evaluating forward and adjoin operator with non-cartesian sampled data. In this paper, the sensitivity map profile, field map information and the spiral k-space data collected from an array of receiver coils are used to reconstruct unaliased images from under-sampled data. The performance of SENSE with real data set identifies the computational issues to be improved for researched.
文摘地理信息系统(Geographical Information System,简称GIS)是处理地理空间数据的信息系统,它集现实世界中对象的空间位置和人文经济信息的管理于一体.全面阐述了如何将Arcinfo软件的Grid模块应用到水利,进行洪水预报系统的开发.将地理信息系统与Grid模块的水文表面分析工具相结合,形成直观的流域环境显示,再通过计算、统计、分析,可获得精确的水文因子数据,为洪水预报系统提供快速、准确的实时流域参数.
