Magneto-optic(MO)coupling of guided optical waves with microwave magnetostatic waves(MSWs)simultaneously excited by multiple radio frequency(RF)signals can lead to multifrequency diffraction effects and then parallel ...Magneto-optic(MO)coupling of guided optical waves with microwave magnetostatic waves(MSWs)simultaneously excited by multiple radio frequency(RF)signals can lead to multifrequency diffraction effects and then parallel processing of RF signals can be realized by using of the characteristics that diffraction efficiencies(DEs)are approximately in direct proportion to RF signals intensities and diffraction angles are related to frequencies of the corresponding RF signals within linear MO interaction region.In this paper,studied is the multifrequency MO Bragg diffraction in first-order MO interaction approximation,and obtained was the approximate analytical expression for principle diffraction efficiency(PDE).Also,put forward was a parallel imaging method of relative intensity of RF signals based on single-frequency diffraction.By calculation and analysis,it is shown that the relative error is not more than 0.3dB for the case of three RF signals within the frequency space of 60MHz.展开更多
A Cartesian grid generation method is developed in this study.Two kinds of solid modeling methods,CSG and STL models,are used for complicated solid modeling.The staircase boundary approximation is implemented to handl...A Cartesian grid generation method is developed in this study.Two kinds of solid modeling methods,CSG and STL models,are used for complicated solid modeling.The staircase boundary approximation is implemented to handle irregular geometries and the computational domain is discretized using a regular Cartesian grid.Using the edge-based integral slice algorithm,the models are sliced with a set of parallel planes to generate 2D slices information.The scan line filling technique is used to achieve grid generation after slicing.Two grid generation examples with a CSG model and a STL model are given to test the capability of the grid generation method.For grid displaying,a method is proposed to remove the hidden surfaces fasten based on the topology of orthogonal hexahedral grids.The parallelization of grid displaying is achieved by employing multi-threaded parallel technique.Parallel test results show that the parallel algorithm has the absolute advantage on speed compared to the serial algorithm.展开更多
The line segment intersection problem is one of the basic problems in computational geometry and has been widely used in spatial analysis in Geographic Information Systems （GIS）. Lots of traditional algorithms study...The line segment intersection problem is one of the basic problems in computational geometry and has been widely used in spatial analysis in Geographic Information Systems （GIS）. Lots of traditional algorithms study the problem in a serial environment. However, in GIS, a spatial object is much more complicated and is considered to be always composed of multiple line segments, and one line segment connects another line segment at its endpoint. On the other hand, along with the advances made in computer hardware, more and more personal computers have multiple cores or CPUs equipped. Thus, to make full use of the increasing computing resources, parallel technique is applied as one of the most available methods. Apparently, the traditional algorithms should be improved to take advantage of the technologies. Under these circumstances, based on the modified uniform grid algorithm, which is adapted to dealing with spatial objects in GIS, this paper proposes a parallel strategy in a shared memory architecture. Also, experimental results are given in the final part of this paper to demonstrate the efficiency this strategy brings.展开更多
基金National Natural Science Foundation of China(60671027)Sichuan Province Basic Research Project(07JY029-089)
文摘Magneto-optic(MO)coupling of guided optical waves with microwave magnetostatic waves(MSWs)simultaneously excited by multiple radio frequency(RF)signals can lead to multifrequency diffraction effects and then parallel processing of RF signals can be realized by using of the characteristics that diffraction efficiencies(DEs)are approximately in direct proportion to RF signals intensities and diffraction angles are related to frequencies of the corresponding RF signals within linear MO interaction region.In this paper,studied is the multifrequency MO Bragg diffraction in first-order MO interaction approximation,and obtained was the approximate analytical expression for principle diffraction efficiency(PDE).Also,put forward was a parallel imaging method of relative intensity of RF signals based on single-frequency diffraction.By calculation and analysis,it is shown that the relative error is not more than 0.3dB for the case of three RF signals within the frequency space of 60MHz.
基金supported by the National Basic Research Program of China(Grant No.2010CB832706)the National Natural Science Foundation of China(Grant No.11172041)the Project of State Key Laboratory of Explosion Science and Technology(Grant No.YBKT14-03)
文摘A Cartesian grid generation method is developed in this study.Two kinds of solid modeling methods,CSG and STL models,are used for complicated solid modeling.The staircase boundary approximation is implemented to handle irregular geometries and the computational domain is discretized using a regular Cartesian grid.Using the edge-based integral slice algorithm,the models are sliced with a set of parallel planes to generate 2D slices information.The scan line filling technique is used to achieve grid generation after slicing.Two grid generation examples with a CSG model and a STL model are given to test the capability of the grid generation method.For grid displaying,a method is proposed to remove the hidden surfaces fasten based on the topology of orthogonal hexahedral grids.The parallelization of grid displaying is achieved by employing multi-threaded parallel technique.Parallel test results show that the parallel algorithm has the absolute advantage on speed compared to the serial algorithm.
文摘The line segment intersection problem is one of the basic problems in computational geometry and has been widely used in spatial analysis in Geographic Information Systems （GIS）. Lots of traditional algorithms study the problem in a serial environment. However, in GIS, a spatial object is much more complicated and is considered to be always composed of multiple line segments, and one line segment connects another line segment at its endpoint. On the other hand, along with the advances made in computer hardware, more and more personal computers have multiple cores or CPUs equipped. Thus, to make full use of the increasing computing resources, parallel technique is applied as one of the most available methods. Apparently, the traditional algorithms should be improved to take advantage of the technologies. Under these circumstances, based on the modified uniform grid algorithm, which is adapted to dealing with spatial objects in GIS, this paper proposes a parallel strategy in a shared memory architecture. Also, experimental results are given in the final part of this paper to demonstrate the efficiency this strategy brings.
