It is a research subject in computer vision to 3D reconstruction of an object represented by a single 2D line drawing. Previous works on 3D reconstruction from 2D line drawings focus on objects with lines, plane, view...It is a research subject in computer vision to 3D reconstruction of an object represented by a single 2D line drawing. Previous works on 3D reconstruction from 2D line drawings focus on objects with lines, plane, view, and so on. This paper mainly studies the 3D reconstruction from 2D line drawings. Besides, a new approach is proposed： it is that for the research of the point coordinates of 2D line drawings, so as to achieve the object reconstruction by the reconstruction of point coordinates. The reconstruction process includes： （1） the collection of point coordinates （X,Y） of 2D line drawings; （2） the derivation of mathematical formula about the reconstruction of the point of 2D line drawings, and calculating the corresponding point of the 3D coordinates; （3） the regeneration of 3D graphics with 3D points; （4） analyze error by the proportional of parallel of axonometric projection, in order to prove the accuracy of the method.展开更多
Aiming at the problem that it is difficult to generate the dynamic decoupling equation of the parallel six-dimensional acceleration sensing mechanism,two typical parallel six-dimensional acceleration sensing mechanism...Aiming at the problem that it is difficult to generate the dynamic decoupling equation of the parallel six-dimensional acceleration sensing mechanism,two typical parallel six-dimensional acceleration sensing mechanisms are taken as examples.By analyzing the scale constraint relationship between the hinge points on the mass block and the hinge points on the base of the sensing mechanism,a new method for establishing the dynamic equation of the sensing mechanism is proposed.Firstly,based on the scale constraint relationship between the hinge points on the mass block and the hinge points on the base of the sensing mechanism,the expression of the branch rod length is obtained.The inherent constraint relationship between the branches is excavated and the branch coordination closed chain of the“12-6”configuration is constructed.The output coordination equation of the sensing mechanism is successfully derived.Secondly,the dynamic equations of“12-4”and“12-6”configurations are constructed by the Newton-Euler method,and the forward decoupling equations of the two configurations are solved by combining the dynamic equations and the output coordination equations.Finally,the virtual prototype experiment is carried out,and the maximum reference errors of the forward decoupling equations of the two configuration sensing mechanisms are 4.23%and 6.53%,respectively.The results show that the proposed method is effective and feasible,and meets the real-time requirements.展开更多
Although the Cramer-Rao Bound(CRB) can be used as the benchmark of estimation algorithm performance,it's too complicated for joint training sequence(TS) design for multiple input multiple output(MIMO) orthogonal f...Although the Cramer-Rao Bound(CRB) can be used as the benchmark of estimation algorithm performance,it's too complicated for joint training sequence(TS) design for multiple input multiple output(MIMO) orthogonal frequency division multiplexing(OFDM) coordination on multiple point(CoMP) systems.So a minimum mean square error(MSE) based sub-optimal sequence design criterion was proposed,including ideal sequence correlation property and sequence length constraint.The simulation results verify the theory analysis.展开更多
Deployment of buoy systems is one of the most important procedures for the operation of buoy system. In the present study, a single-point mooring buoy system which contains surface buoy, cable segments with components...Deployment of buoy systems is one of the most important procedures for the operation of buoy system. In the present study, a single-point mooring buoy system which contains surface buoy, cable segments with components, anchor and so on is modeled by applying multi-body dynamics method. The motion equations are developed in discrete node description and fully Cartesian coordinates. Then numerical method is used to solve the ordinary differential equations and dynamics simulations are achieved while anchor is casting from board. The trajectories and velocities of different nodes without current and with current in buoy system are obtained. The transient tension force of each part of the cable is analyzed in the process of deployment. Numerical results indicate that the transient payload increases to a peak value when the anchor is touching the seabed and the maximum tension force will vary with different floating configuration. This work is helpful for design and deployment planning of buoy system.展开更多
The cloud radio access network(C-RAN) has recently been proposed as an important component of the next generation wireless networks providing opportunities for improving both spectral and energy effi ciencies. The per...The cloud radio access network(C-RAN) has recently been proposed as an important component of the next generation wireless networks providing opportunities for improving both spectral and energy effi ciencies. The performance of this network structure is however constrained by severe inter-cell interference due to the limited capacity of fronthaul between the radio remote heads(RRH) and the base band unit(BBU) pool. To achieve performance improvement taking full advantage of centralized processing capabilities of C-RANs,a set of RRHs can jointly transmit data to the same UE for improved spectral effi ciency. In this paper,a user centralized joint coordinated transmission(UC-JCT) scheme is put forth to investigate the downlink performance of C-RANs. The most important benefit the proposed strategy is the ability to translate what would have been the most dominant interfering sources to usable signal leading to a signifi cantly improved performance. Stochastic geometry is utilized to model the randomness of RRH location and provides a reliable performance analysis. We derive an analytical expression for the closed integral form of the coverage probability of a typical UE. Simulation results confirm the accuracy of our analysis and demonstrate that significant performance gain can be achieved from the proposed coordination schemes.展开更多
We studied a pure coordination game in which swimmers had to agree on the distance that they would swim underwater up a line after diving into a swimming pool. The swimmers were not able to communicate with each other...We studied a pure coordination game in which swimmers had to agree on the distance that they would swim underwater up a line after diving into a swimming pool. The swimmers were not able to communicate with each other. To win the game, the swimmer had to surface at exactly the same point as his partner. This pure coordination game was played by 81 swimmers, 43 of whom then put their decisions into practice in a 25-metre pool. The results revealed the presence of two Schelling points. One point （at 12.5 metres） was that predicted by theory and corresponded to half the maximum possible distance. The other Schelling point （at 25 metres） was practical in nature and reflected a taste for underwater swimming--even though performance （in terms of the distance swum underwater） was not relevant in this game. The results show that swimmers underestimate their water competence when they are not subjected to a competitive challenge.展开更多
In modern warfare,unpowered glide munitions,represented by JDAM,are widely used.Accurately predicting the future trajectory of such targets is crucial for intercepting them.This paper proposes a future point predictio...In modern warfare,unpowered glide munitions,represented by JDAM,are widely used.Accurately predicting the future trajectory of such targets is crucial for intercepting them.This paper proposes a future point prediction method for unpowered gliding targets based on attitude computation.By estimating the current state of the target,we derive the target’s attitude coordinate system.Subsequently,the paper analyzes the forces acting on the target and updates the state transition matrix,ultimately calculating the future position of the target.Experimental results show that,compared to traditional methods,this approach improves the accuracy of future point predictions by 9%to 45%.展开更多
文摘It is a research subject in computer vision to 3D reconstruction of an object represented by a single 2D line drawing. Previous works on 3D reconstruction from 2D line drawings focus on objects with lines, plane, view, and so on. This paper mainly studies the 3D reconstruction from 2D line drawings. Besides, a new approach is proposed： it is that for the research of the point coordinates of 2D line drawings, so as to achieve the object reconstruction by the reconstruction of point coordinates. The reconstruction process includes： （1） the collection of point coordinates （X,Y） of 2D line drawings; （2） the derivation of mathematical formula about the reconstruction of the point of 2D line drawings, and calculating the corresponding point of the 3D coordinates; （3） the regeneration of 3D graphics with 3D points; （4） analyze error by the proportional of parallel of axonometric projection, in order to prove the accuracy of the method.
基金supported in part by the National Natural Science Foundation of China(No.51405237)。
文摘Aiming at the problem that it is difficult to generate the dynamic decoupling equation of the parallel six-dimensional acceleration sensing mechanism,two typical parallel six-dimensional acceleration sensing mechanisms are taken as examples.By analyzing the scale constraint relationship between the hinge points on the mass block and the hinge points on the base of the sensing mechanism,a new method for establishing the dynamic equation of the sensing mechanism is proposed.Firstly,based on the scale constraint relationship between the hinge points on the mass block and the hinge points on the base of the sensing mechanism,the expression of the branch rod length is obtained.The inherent constraint relationship between the branches is excavated and the branch coordination closed chain of the“12-6”configuration is constructed.The output coordination equation of the sensing mechanism is successfully derived.Secondly,the dynamic equations of“12-4”and“12-6”configurations are constructed by the Newton-Euler method,and the forward decoupling equations of the two configurations are solved by combining the dynamic equations and the output coordination equations.Finally,the virtual prototype experiment is carried out,and the maximum reference errors of the forward decoupling equations of the two configuration sensing mechanisms are 4.23%and 6.53%,respectively.The results show that the proposed method is effective and feasible,and meets the real-time requirements.
基金International Science&Technology Cooperation Projects of Qinghai,China(Nos.2013-H-811,2014-HZ-821)Chunhui Plan Projects,China(Nos.Z2014013,Z2014014)
文摘Although the Cramer-Rao Bound(CRB) can be used as the benchmark of estimation algorithm performance,it's too complicated for joint training sequence(TS) design for multiple input multiple output(MIMO) orthogonal frequency division multiplexing(OFDM) coordination on multiple point(CoMP) systems.So a minimum mean square error(MSE) based sub-optimal sequence design criterion was proposed,including ideal sequence correlation property and sequence length constraint.The simulation results verify the theory analysis.
基金supported by the National Natural Science Foundation of China (Grant No. 51175484)the Science Foundation of Shandong Province (Grant No. ZR2010EM052)
文摘Deployment of buoy systems is one of the most important procedures for the operation of buoy system. In the present study, a single-point mooring buoy system which contains surface buoy, cable segments with components, anchor and so on is modeled by applying multi-body dynamics method. The motion equations are developed in discrete node description and fully Cartesian coordinates. Then numerical method is used to solve the ordinary differential equations and dynamics simulations are achieved while anchor is casting from board. The trajectories and velocities of different nodes without current and with current in buoy system are obtained. The transient tension force of each part of the cable is analyzed in the process of deployment. Numerical results indicate that the transient payload increases to a peak value when the anchor is touching the seabed and the maximum tension force will vary with different floating configuration. This work is helpful for design and deployment planning of buoy system.
基金supported in part by the National Natural Science Foundation of China (Grant No. 61222103)the Beijing Natural Science Foundation (Grant No. 4131003)+1 种基金the Specialized Research Fund for the Doctoral Program of Higher Education (SRFDP) (Grant No. 20120005140002)the National High Technology Research and Development Program (863 Program) of China under Grant No. 2014AA01A707
文摘The cloud radio access network(C-RAN) has recently been proposed as an important component of the next generation wireless networks providing opportunities for improving both spectral and energy effi ciencies. The performance of this network structure is however constrained by severe inter-cell interference due to the limited capacity of fronthaul between the radio remote heads(RRH) and the base band unit(BBU) pool. To achieve performance improvement taking full advantage of centralized processing capabilities of C-RANs,a set of RRHs can jointly transmit data to the same UE for improved spectral effi ciency. In this paper,a user centralized joint coordinated transmission(UC-JCT) scheme is put forth to investigate the downlink performance of C-RANs. The most important benefit the proposed strategy is the ability to translate what would have been the most dominant interfering sources to usable signal leading to a signifi cantly improved performance. Stochastic geometry is utilized to model the randomness of RRH location and provides a reliable performance analysis. We derive an analytical expression for the closed integral form of the coverage probability of a typical UE. Simulation results confirm the accuracy of our analysis and demonstrate that significant performance gain can be achieved from the proposed coordination schemes.
文摘We studied a pure coordination game in which swimmers had to agree on the distance that they would swim underwater up a line after diving into a swimming pool. The swimmers were not able to communicate with each other. To win the game, the swimmer had to surface at exactly the same point as his partner. This pure coordination game was played by 81 swimmers, 43 of whom then put their decisions into practice in a 25-metre pool. The results revealed the presence of two Schelling points. One point （at 12.5 metres） was that predicted by theory and corresponded to half the maximum possible distance. The other Schelling point （at 25 metres） was practical in nature and reflected a taste for underwater swimming--even though performance （in terms of the distance swum underwater） was not relevant in this game. The results show that swimmers underestimate their water competence when they are not subjected to a competitive challenge.
文摘In modern warfare,unpowered glide munitions,represented by JDAM,are widely used.Accurately predicting the future trajectory of such targets is crucial for intercepting them.This paper proposes a future point prediction method for unpowered gliding targets based on attitude computation.By estimating the current state of the target,we derive the target’s attitude coordinate system.Subsequently,the paper analyzes the forces acting on the target and updates the state transition matrix,ultimately calculating the future position of the target.Experimental results show that,compared to traditional methods,this approach improves the accuracy of future point predictions by 9%to 45%.
