This paper presents the closed-form expression to the expected density of progress for wireless ad hoc networks with Nakagami-m fading. The expected density of progress is defined as the expectation of a product betwe...This paper presents the closed-form expression to the expected density of progress for wireless ad hoc networks with Nakagami-m fading. The expected density of progress is defined as the expectation of a product between the number of simultaneous successful transmission per unit area and the distance towards the destination. Numerical results show that the expected density of progress is determined by two factors, terminal density and the probability that a terminal attempts to transmit.展开更多
The reflecting and transmitting effects of a planar unidirectionally conducting screen are analyzed based on the accurate closed-form expression for electric field of an arbitrarily oriented electric dipole.For a dipo...The reflecting and transmitting effects of a planar unidirectionally conducting screen are analyzed based on the accurate closed-form expression for electric field of an arbitrarily oriented electric dipole.For a dipole oriented along the wire elements of the screen,the screen acts as a perfectly electrically conducting plane.For a dipole perpendicular to the wire elements,the fields reflected by the screen can be interpreted as the contribution of an image dipole and image transmission-line current source,while the transmitted field is arisen from image transmission-line source.The expressions of related surface waves are derived and can be compared with previous results.展开更多
For a Riemann surface X of conformally finite type （g, n）, let dT, dL and dpi （i = 1, 2） be the Teichmuller metric, the length spectrum metric and Thurston＇s pseudometrics on the Teichmutler space T（X）, respect...For a Riemann surface X of conformally finite type （g, n）, let dT, dL and dpi （i = 1, 2） be the Teichmuller metric, the length spectrum metric and Thurston＇s pseudometrics on the Teichmutler space T（X）, respectively. The authors get a description of the Teichmiiller distance in terms of the Jenkins-Strebel differential lengths of simple closed curves. Using this result, by relatively short arguments, some comparisons between dT and dL, dpi （i = 1, 2） on Tε（X） and T（X） are obtained, respectively. These comparisons improve a corresponding result of Li a little. As applications, the authors first get an alternative proof of the topological equivalence of dT to any one of dL, dp1 and dp2 on T（X）. Second, a new proof of the completeness of the length spectrum metric from the viewpoint of Finsler geometry is given. Third, a simple proof of the following result of Liu-Papadopoulos is given： a sequence goes to infinity in T（X） with respect to dT if and only if it goes to infinity with respect to dL （as well as dpi （i = 1, 2））.展开更多
基金Supported by the National High Technology and Development Program of China （No.2007AA10Z235） , the National Basic Research Program of China（No.2009CB320407）, the National Natural Science Foundation of China（No.60872049,60871042,60971082,60972073）, and the National Science Specific Project（2009ZX03003-011）.
文摘This paper presents the closed-form expression to the expected density of progress for wireless ad hoc networks with Nakagami-m fading. The expected density of progress is defined as the expectation of a product between the number of simultaneous successful transmission per unit area and the distance towards the destination. Numerical results show that the expected density of progress is determined by two factors, terminal density and the probability that a terminal attempts to transmit.
文摘The reflecting and transmitting effects of a planar unidirectionally conducting screen are analyzed based on the accurate closed-form expression for electric field of an arbitrarily oriented electric dipole.For a dipole oriented along the wire elements of the screen,the screen acts as a perfectly electrically conducting plane.For a dipole perpendicular to the wire elements,the fields reflected by the screen can be interpreted as the contribution of an image dipole and image transmission-line current source,while the transmitted field is arisen from image transmission-line source.The expressions of related surface waves are derived and can be compared with previous results.
基金supported by the National Natural Science Foundation of China (No. 10871211)
文摘For a Riemann surface X of conformally finite type （g, n）, let dT, dL and dpi （i = 1, 2） be the Teichmuller metric, the length spectrum metric and Thurston＇s pseudometrics on the Teichmutler space T（X）, respectively. The authors get a description of the Teichmiiller distance in terms of the Jenkins-Strebel differential lengths of simple closed curves. Using this result, by relatively short arguments, some comparisons between dT and dL, dpi （i = 1, 2） on Tε（X） and T（X） are obtained, respectively. These comparisons improve a corresponding result of Li a little. As applications, the authors first get an alternative proof of the topological equivalence of dT to any one of dL, dp1 and dp2 on T（X）. Second, a new proof of the completeness of the length spectrum metric from the viewpoint of Finsler geometry is given. Third, a simple proof of the following result of Liu-Papadopoulos is given： a sequence goes to infinity in T（X） with respect to dT if and only if it goes to infinity with respect to dL （as well as dpi （i = 1, 2））.
