一种高速实时数据采集系统的设计与实现

介绍了一种采用PCI总线实现数据高速采集、传输的设计方法。并提供了PCI总线控制器的实现和系统的硬件电路设计。最后介绍了设备驱动程序及应用程序的软件实现方法。     

State space collapse with application to heavy traffic limits for multiclass queueing networks

Heavy traffic limits for multiclass queueing networks are a topic of continuing interest. Presently, the class of networks for which these limits have been rigorously derived is restricted. An important ingredient in such work is the demonstration of state space collapse. Here, we demonstrate state space collapse for two families of networks, first-in first-out (FIFO) queueing networks of Kelly type and head-of-the-line proportional processor sharing (HLPPS) queueing networks. We then apply our techniques to more general networks. To demonstrate state space collapse for FIFO networks of Kelly type and HLPPS networks, we employ law of large number estimates to show a form of compactness for appropriately scaled solutions. The limits of these solutions are next shown to satisfy fluid model equations corresponding to the above queueing networks. Results from Bramson [4,5] on the asymptotic behavior of these limits then imply state space collapse. The desired heavy traffic limits for FIFO networks of Kelly type and HLPPS networks follow from this and the general criteria set forth in the companion paper Williams [41]. State space collapse and the ensuing heavy traffic limits also hold for more general queueing networks, provided the solutions of their fluid model equations converge. Partial results are given for such networks, which include the static priority disciplines. This revised version was published online in June 2006 with corrections to the Cover Date.     

基于FPGA密集假目标干扰的实现

在现代电子战中,应对新体制雷达、雷达干扰机转向采用欺骗性干扰方式,结合DRFM的机理,介绍了可控变间隔的密集假目标产生机理,基于FPGA内部IP核 FIFO 产生密集假目标,通过控制FIFO的存储深度来实现假目标的延迟时间;通过开关控制假目标的输出数量。仿真分析了假目标产生机理的正确性,同时验证了密集假目标产生的硬件可实现性,并给出了硬件实现假目标调幅调频的方法,为相关雷达干扰机硬件实现提供了参考。     

一种高性能的异步FIFO结构

针对现有FIFO设计方法的不足,本文提出一种新的异步FIFO结构——WG-FIFO,采用加权Gray码进行指针编码,采用实时状态检测器控制写/读操作.模拟结果表明,在FIFO深度为4~16的情况下,该结构与已有的FIFO结构相比在性能、面积开销以及写/读操作效率等方面都获得了明显的改善.特别地,当FIFO的深度为8、宽度为32时,相比B-FIFO,WG-FIFO的最高时钟频率提高31.6%,单元面积减少17.1%,且写/读效率最大能提高47%.     

Convergence to equilibria for fluid models of FIFO queueing networks

The qualitative behavior of open multiclass queueing networks is currently a topic of considerable activity. An important goal is to formulate general criteria for when such networks possess equilibria, and to characterize these equilibria when possible. Fluid models have recently become an important tool for such purposes. We are interested here in a family of such models, FIFO fluid models of Kelly type. That is, the discipline is first-in, first-out, and the service rate depends only on the station. To study such models, we introduce an entropy function associated with the state of the system. The corresponding estimates show that if the traffic intensity function is at most 1, then such fluid models converge exponentially fast to equilibria with fixed concentrations of customer types throughout each queue. When the traffic intensity function is strictly less than 1, the limit is always the empty state and occurs after a finite time. A consequence is that generalized Kelly networks with traffic intensity strictly less than 1 are positive Harris recurrent, and hence possess unique equilibria.1991Mathematics Subject Classification, 60K25, 68M20, 90B10. Partially supported by NSF Grant DMS-93-00612.