This paper presents a Doppler passive location method for moving targets with fixed single station using the Doppler frequency shift and time difference information.First,based on the relationship between frequency sh...This paper presents a Doppler passive location method for moving targets with fixed single station using the Doppler frequency shift and time difference information.First,based on the relationship between frequency shift and path difference,the virtual path difference is calculated from the measured value of Doppler frequency shift by means of mean value correction.Then,under the assumption that the target is moving at a constant speed along a straight line,two coaxial virtual double base arrays are constructed by using the moving track of the moving target based on the method of fixed period time difference.On this basis,the moving distance of the moving target can be calculated by using the ratio relationship between the frequency difference and the radial distance between the two adjacent detection points in the middle of the array,and the linear solution of the two double base path difference positioning equations.At this point,the relative coordinate position of the moving target can be obtained by directly using the linear solution of the double base path difference positioning equation again.展开更多
Virtual path concept has several valuable features to re construct an economical and efficient ATM network.The most important effect of VPs is to afford transmission efficiently through the dynamic control of VPs reso...Virtual path concept has several valuable features to re construct an economical and efficient ATM network.The most important effect of VPs is to afford transmission efficiently through the dynamic control of VPs resource including buffer and bandwidth.This paper described the problem of dynamic resource control of VP in ATM networks.Based on a discrete event dynamic model of resource control of VP in ATM networks,the optimal control law of resource allocation of VP in ATM networks with the method of dynamic programming was presented.The results of the theorem proof and simulation show that the dynamic control is more efficient to reduce the calls block rate comparing with the static allocation.展开更多
This article proposes a novel fuzzy virtual force （FVF） method for unmanned aerial vehicle （UAV） path planning in compli-cated environment. An integrated mathematical model of UAV path planning based on virtual fo...This article proposes a novel fuzzy virtual force （FVF） method for unmanned aerial vehicle （UAV） path planning in compli-cated environment. An integrated mathematical model of UAV path planning based on virtual force （VF） is constructed and the corresponding optimal solving method under the given indicators is presented. Specifically,a fixed step method is developed to reduce computational cost and the reachable condition of path planning is proved. The Bayesian belief network and fuzzy logic reasoning theories are applied to setting the path planning parameters adaptively,which can reflect the battlefield situation dy-namically and precisely. A new way of combining threats is proposed to solve the local minima problem completely. Simulation results prove the feasibility and usefulness of using FVF for UAV path planning. Performance comparisons between the FVF method and the A＊ search algorithm demonstrate that the proposed approach is fast enough to meet the real-time requirements of the online path planning problems.展开更多
Although computer capabilities have been improved significantly, a large-scale virtual reality （VR） system demands much more in terms of memory and computation than the current computer systems can offer. This paper...Although computer capabilities have been improved significantly, a large-scale virtual reality （VR） system demands much more in terms of memory and computation than the current computer systems can offer. This paper discusses two important issues related to VR performance and applications in building navigation. These are dynamic loading of models based on cell segmentation for the optimal VR operation, and the route optimization based on path planning for easy navigation. The VR model of engineering and information technology complex （EITC） building at the University of Manitoba is built as an example to show the feasibility of the proposed methods. The reality, enhanced by three-dimensional （3D） real-time interactivity and visualization, leads navigators into a state of the virtual building immersion.展开更多
We present a new algorithm to compute a geodesic path over a triangle mesh. Based on Novotni＇s propagating wavefront method which is similar to the well known Dijkstra algorithm, we made some improvements which Novot...We present a new algorithm to compute a geodesic path over a triangle mesh. Based on Novotni＇s propagating wavefront method which is similar to the well known Dijkstra algorithm, we made some improvements which Novotni had missed and we also gave the method to find out the geodesic path which Novotni had not. It can handle both convex and non-convex surfaces or even with boundaries. Experiment results show that our method works very well both in efficiency and precision.展开更多
文摘This paper presents a Doppler passive location method for moving targets with fixed single station using the Doppler frequency shift and time difference information.First,based on the relationship between frequency shift and path difference,the virtual path difference is calculated from the measured value of Doppler frequency shift by means of mean value correction.Then,under the assumption that the target is moving at a constant speed along a straight line,two coaxial virtual double base arrays are constructed by using the moving track of the moving target based on the method of fixed period time difference.On this basis,the moving distance of the moving target can be calculated by using the ratio relationship between the frequency difference and the radial distance between the two adjacent detection points in the middle of the array,and the linear solution of the two double base path difference positioning equations.At this point,the relative coordinate position of the moving target can be obtained by directly using the linear solution of the double base path difference positioning equation again.
文摘Virtual path concept has several valuable features to re construct an economical and efficient ATM network.The most important effect of VPs is to afford transmission efficiently through the dynamic control of VPs resource including buffer and bandwidth.This paper described the problem of dynamic resource control of VP in ATM networks.Based on a discrete event dynamic model of resource control of VP in ATM networks,the optimal control law of resource allocation of VP in ATM networks with the method of dynamic programming was presented.The results of the theorem proof and simulation show that the dynamic control is more efficient to reduce the calls block rate comparing with the static allocation.
基金National Natural Science Foundation of China (60975073)Aeronautical Science Foundation of China (2008ZC13011)+1 种基金Research Foundation for Doctoral Program of Higher Education of China (20091102110006)Fundamental Research Funds for the Central Universities
文摘This article proposes a novel fuzzy virtual force （FVF） method for unmanned aerial vehicle （UAV） path planning in compli-cated environment. An integrated mathematical model of UAV path planning based on virtual force （VF） is constructed and the corresponding optimal solving method under the given indicators is presented. Specifically,a fixed step method is developed to reduce computational cost and the reachable condition of path planning is proved. The Bayesian belief network and fuzzy logic reasoning theories are applied to setting the path planning parameters adaptively,which can reflect the battlefield situation dy-namically and precisely. A new way of combining threats is proposed to solve the local minima problem completely. Simulation results prove the feasibility and usefulness of using FVF for UAV path planning. Performance comparisons between the FVF method and the A＊ search algorithm demonstrate that the proposed approach is fast enough to meet the real-time requirements of the online path planning problems.
基金supported by Discovery Grants of National Science and Engineering Research Council of Canada (NSERC) and Faculty of Engineering at University of Manitoba
文摘Although computer capabilities have been improved significantly, a large-scale virtual reality （VR） system demands much more in terms of memory and computation than the current computer systems can offer. This paper discusses two important issues related to VR performance and applications in building navigation. These are dynamic loading of models based on cell segmentation for the optimal VR operation, and the route optimization based on path planning for easy navigation. The VR model of engineering and information technology complex （EITC） building at the University of Manitoba is built as an example to show the feasibility of the proposed methods. The reality, enhanced by three-dimensional （3D） real-time interactivity and visualization, leads navigators into a state of the virtual building immersion.
基金This work was supported by National Natural Science Foundation of PRC(No.60503058,No.60533080)the Science and Technology Fund of Huawei Technologies Co.,Ltd.
文摘We present a new algorithm to compute a geodesic path over a triangle mesh. Based on Novotni＇s propagating wavefront method which is similar to the well known Dijkstra algorithm, we made some improvements which Novotni had missed and we also gave the method to find out the geodesic path which Novotni had not. It can handle both convex and non-convex surfaces or even with boundaries. Experiment results show that our method works very well both in efficiency and precision.
