基于ModBus协议的负载模拟系统设计

为了对实际的外部设备进行有效的控制,设计了一种基于 ModBus 协议的负载物理模拟平台控制系统。上位机采用C++ Builder XE2进行主站的通信程序设计,下位机采用西门子 S7-200 SMART,使用 ModBus RTU 协议库设计通信程序,将计算机与 PLC 连接起来,组成高性价比的负载物理模拟平台自动控制系统。通过上位机的数据的发送和接收实验,验证了设计的负载物理模拟平台控制系统的有效性和可行性。     

A queuing model for distributed scheduling in IEEE 802.16 wireless mesh networks

The IEEE 802.16 standard for wireless broadband networks includes the mesh mode in its specifications, where network nodes interact to deliver packets from a client to a remote destination through intermediate nodes. This paper presents a study of the capacity of IEEE 802.16 wireless networks in mesh mode by using M/G/1/L queuing model that represents each network node by incorporating the features of the standard in order to calculate the average delay and throughput in the node. An iterative method integrates the calculation results at each node, obtaining the end‐to‐end delay from any node of the mesh to the Base Station. Because of multiple hops, a node far from the Base Station may have its flows damaged. To minimize this problem, we propose a criterion for a fair distribution of resources. We show the numerical results of the model which indicate a good fit when compared with simulation results. Copyright © 2013 John Wiley & Sons, Ltd.     

The implementation of IEEE 802.16m protocol module for ns-3 simulator

This paper presents the first IEEE 802.16m medium access control (MAC) protocol module embedded in the network simulator version 3 (ns-3). The designed module provides a validation tool for researchers to verify simulated results related to the IEEE 802.16m. This module supports the basic MAC functions which includes an initial ranging (IR) function; four types of bandwidth request (BR) procedures; five types of standard-specified quality-of-service (QoS); a QoS-based transmission scheduler; an adaptive modulation and coding (AMC) selection function; a physical (PHY) layer with a channel propagation model. The designed module provides modification flexibility to adapt to other simulation modules. Various scenarios are simulated to show the capacity of the implemented IEEE 802.16m module in details. Results of different types of traffic are tested with the path loss effect on transmission to visualize the numeric capability of the module.     

计算机节能监视系统的设计与实现

计算机节能是节能减排的一项举措,通过编制程序来获取目的计算机的活动性,有效的掌握计算机开机情况。     

Bounded memory protocols

It is well-known that the Dolev–Yao adversary is a powerful adversary. Besides acting as the network, intercepting, decomposing, composing and sending messages, he can remember as much information as he needs. That is, his memory is unbounded. We recently proposed a weaker Dolev–Yao like adversary, which also acts as the network, but whose memory is bounded. We showed that this Bounded Memory Dolev–Yao adversary, when given enough memory, can carry out many existing protocol anomalies. In particular, the known anomalies arise for bounded memory protocols, where although the total number of sessions is unbounded, there are only a bounded number of concurrent sessions and the honest participants of the protocol cannot remember an unbounded number of facts or an unbounded number of nonces at a time. This led us to the question of whether it is possible to infer an upper-bound on the memory required by the Dolev–Yao adversary to carry out an anomaly from the memory restrictions of the bounded protocol. This paper answers this question negatively (Theorem 8).     

基于FPGA的千兆以太网协议分析技术

该文主要阐述在FPGA（Field—Programmable Gate Array）内千兆以太网协议数据流帧的生成、编码、组帧、解帧及协议帧分析,详细地阐述了BCM5421和FPGA组合的硬件设计技术、协议发生的FPGA设计技术、协议解码、过滤、性能分析的FPGA设计技术等关键技术的实现途径。     

TCP拥塞控制建模分析方法

随着互联网技术的迅猛发展,传输控制协议(TCP)传输面临越来越严重的拥塞问题。为了更深入了解拥塞现象发生的原因,设计有效的拥塞控制机制,基于着色Petri网性能评价理论,论述了TCP传输控制建模分析的方法,分析了拥塞发生中拥塞窗口和缓存队列的变化过程。在分析结果的基础上,提出了在设计拥塞机制时应综合考虑窗口大小和缓存大小,在控制发送速率的基础上,达到较好的带宽利用率。     

Femto系统设备兼容性故障的定位分析与解决方法

通过研究和分析Femto与核心网之间的信令协议,探讨了由于不同厂家对3GPP协议中描述理解的不同而造成的设备兼容性问题,并提出了切实可行的故障定位及处理方法,为解决类似问题提供了思路。     

NIDS模型中检测引擎模块的设计与实现

设计和实现了一个NIDS模型中检测引擎模块,并且在Linux系统下实现了其功能,采用一种新的基于协议分析的检测算法.提高了检测能力,减少了漏报率.