一、程序中的按键处理应用程序中,对按键和鼠标的控制十分重要,它常常用于控制程序的走向。在FoxPro2.5 for DOS中,提供了很多的命令和函数,用以控制按键和鼠标,其主要的命令和函数有:INKEY()LASTKEY()READKEY()ON KEY ON KEY= ON KEY L...一、程序中的按键处理应用程序中,对按键和鼠标的控制十分重要,它常常用于控制程序的走向。在FoxPro2.5 for DOS中,提供了很多的命令和函数,用以控制按键和鼠标,其主要的命令和函数有:INKEY()LASTKEY()READKEY()ON KEY ON KEY= ON KEY LABELON ESCAPE ON ERROR PUSH KEYPOP KEY其中ON KEY LABEL命令经常使用,与ONKEY命令的最大不同在于用户可一次设多个ON KEYLABEL命令,使多个按键被设置成热键以分别执行不同的命令或程序。ON展开更多
In this paper, a generalized three-dimensional(3D) scattering channel model for macrocellular land mobile environments is considered. This model simultaneously describes angular arrival of multi-path signals in the az...In this paper, a generalized three-dimensional(3D) scattering channel model for macrocellular land mobile environments is considered. This model simultaneously describes angular arrival of multi-path signals in the azimuth and elevation planes in an environment where uniformly distributed scatterers are assumed to be present in hemispheroids around the base station(BS) and mobile station(MS). Using this channel model, we first derive the closed-form expression for the joint and marginal probability density functions of the angle-of-arrival and time-of-arrival measured at the BS and the MS corresponding to the azimuth and elevation angles. Next, we derive an expression for the Doppler spectral distribution caused by motion of the MSs. Furthermore, we analyze the performance of multiple-input multiple-output antenna systems numerically. The results show that the proposed 3D scattering channel model performs better than previously proposed two-dimensional(2D) models for indoor and outdoor environments. We compare the results with previous scattering channel models and measurement results to validate the generalizability of our model.展开更多
文摘一、程序中的按键处理应用程序中,对按键和鼠标的控制十分重要,它常常用于控制程序的走向。在FoxPro2.5 for DOS中,提供了很多的命令和函数,用以控制按键和鼠标,其主要的命令和函数有:INKEY()LASTKEY()READKEY()ON KEY ON KEY= ON KEY LABELON ESCAPE ON ERROR PUSH KEYPOP KEY其中ON KEY LABEL命令经常使用,与ONKEY命令的最大不同在于用户可一次设多个ON KEYLABEL命令,使多个按键被设置成热键以分别执行不同的命令或程序。ON
基金supported by the National Nature Science Foundation of China (No.61471153)the Scientific and Technological Support Project (Industry) of Jiangsu Province (No. BE2011195)the Major Program of the Natural Science Foundation of Institution of Higher Education of Jiangsu Province (No. 14KJA510001)
文摘In this paper, a generalized three-dimensional(3D) scattering channel model for macrocellular land mobile environments is considered. This model simultaneously describes angular arrival of multi-path signals in the azimuth and elevation planes in an environment where uniformly distributed scatterers are assumed to be present in hemispheroids around the base station(BS) and mobile station(MS). Using this channel model, we first derive the closed-form expression for the joint and marginal probability density functions of the angle-of-arrival and time-of-arrival measured at the BS and the MS corresponding to the azimuth and elevation angles. Next, we derive an expression for the Doppler spectral distribution caused by motion of the MSs. Furthermore, we analyze the performance of multiple-input multiple-output antenna systems numerically. The results show that the proposed 3D scattering channel model performs better than previously proposed two-dimensional(2D) models for indoor and outdoor environments. We compare the results with previous scattering channel models and measurement results to validate the generalizability of our model.
