时隙ALOHA在MATLAB中的仿真

时隙ALOHA使用了各种控制算法以保证系统的稳定性,在应用控制算法前,必须对算法的性能进行前期仿真测试．在比较三种常用网络仿真工具的基础上,分析了MATLAB离散事件仿真原理及基于蒙特卡洛法的随机数生成原理．给出了MATLAB仿真平台下实现时隙ALoHA控制算法的流程图,并依据该流程编写了MATLAB代码对时隙ALOHA的伪贝叶控制算法性能进行测试．仿真结果表示,MATLAB能很好的实现对时隙ALOHA控制算法的仿真．     

下一代网络过渡技术研究

目前,IPv6及相关协议已经相对成熟,然而,IPv4网络向IPv6网络的过渡和互通仍然是个艰巨的任务,直接影响了IPv6的发展。讨论了IPv4向IPv6过渡的3种基本技术,阐述了IPv4向IPv6分阶段过渡的流程。     

SVC的RTP封装及其在NS2包调度中的应用研究

随着流媒体技术的发展,实时传输协议RTP被广泛用于各种多媒体传榆系统中,为实时应用提供端到端的传输。可伸缩视频编码（SVC）因其时域、空间和质量的可分级,能够为用户提供可分级性更强的视频流,满足不同终端设备用户的需求。本文针对SVC视频流应用于NS2网络传输仿真而设计了一套可伸缩视频编码的RTP卦装方案,并将其应用于NS2仿真环境,实现了真实视频流的实时调度与传输。实验结果验证了该RTP卦装方案的正确性和有效性。     

基于目录服务器的Oracle Net应用

本文分析了OracleNet网络的体系结构,提出了基于目录服务器的OracleNet网络应用解决方案及具体实施方法。     

基于PCI Express总线协议开销的性能分析

在计算机内部和外部,统一总线标准和提高总线带宽一直是计算机发展的重要问题,本文从技术的角度介绍了PCI Express总线的基本拓扑结构和体系结构,并详细介绍了PCI Express总线的分层体系结构,然后对总线的协议开销来源,以及计算方法进行了详细的阐述,并结合实例进行了计算与分析。     

Assessment of the lactate and ventilatory thresholds by breathing frequency in runners

The aim of this study was to establish the validity of the breakpoint in breathing frequency for the assessment of the lactate threshold and the ventilatory threshold during incremental running exercise. Twelve trained runners (mean +/- s: age 29 +/- 8 years; body mass 68.7 8.8 kg; V O 2m ax 57.9 +/- 4.1 ml . kg -1 . min -1 ) performed randomly assigned incremental treadmill tests on separate days. In addition to the assessment of the V O 2m ax (Test 1), the subjects performed two standard multi-stage treadmill tests (4-min stages) for the assessment of the lactate threshold while wearing (Test 2) and not wearing (Test 3) a standard mouthpiece and noseclip arrangement. Breathing frequency was measured by a thermistor, which was positioned in the back of the mouthpiece for Test 2, and fixed 3 cm in front of the mouth using a headband and flexible wiring for Test 3. All exercise tests were recorded on videotape and mean breathing frequency and stride rate were calculated for the last minute of each stage from real-time playback of the videotapes. The breathing frequency breakpoint was determined in six subjects only for Test 2 and in five subjects only for Test 3. For Test 2, there were no differences between the breakpoint in breathing frequency (14.7 +/- 0.9 km . h - 1), the lactate threshold (14.7 +/- 0.9 km . h -1 ) and the ventilatory threshold (14.7 +/- 1.1 km . h -1 ). For Test 3, the breakpoint in breathing frequency (14.0 +/- 1.0 km . h -1 ) was not appreciably different from the lactate threshold (14.7 +/- 1.2 km . h -1 ). Hey plots showed marked interindividual differences in the responses of breathing frequency and tidal volume to exercise. In four subjects, the ventilatory threshold was mediated by a non-linear increase in tidal volume, with breathing frequency either increasing in a linear manner (n = 1) or remaining constant owing to entrainment of breathing frequency to cadence (n = 3). We conclude that the breakpoint in breathing frequency does not provide a valid method for the field-based assessment of the lactate or ventilatory thresholds in most subjects for running exercise.     

WAP手机图书馆的应用研究与实现

文章通过分析手机图书馆的应用现状和WAP2.0技术的特点,确立了手机图书馆功能结构模型和系统建设方案,并在此基础上,开发实现了桂林理工大学WAP手机图书馆系统。     

基于ISDN计算机网络体系结构分析

ISDN是在IDN基础上发展起来的,由于使用单一的网络来提供不同的业务,而无需为每种业务单独建网,ISDN大大提高了网络资源的利用率.用户应用的业务不同,却可以使用统一接口.我国数字电话网已基本形成,丰富的IDN资源是发展ISDN的最大优势.     

无线Mesh网中基于声誉的安全路由协议研究

无线Mesh网(wireless mesh networks,WMNs)是一种新兴的无线网络技术,支持节点多跳路由和转发功能。节点合作与否是实现通信的关键。在缺少预先约定的信任关系时,判断节点合作性的安全机制是解决恶意节点破坏网络通信的有效手段。在对WMNs中AODV协议安全分析的基础上,提出了一种基于局部声誉值的安全路由解决方案。