基于PowerPC的流媒体QoS监测工具

文章提出和实现了一种新颖的基于PowerPC的网络多媒体流QoS监测工具:MDUMP.该系统通过实现内核态流媒体数据分析.提高了QoS信息获取的实时性.采用SoC设计方法,网络多媒体QoS监控丢你个海,器与流媒体服务分离,解决了传统网络多媒体QoS监控工具的依赖性问题.另外.该系统又充分利用了PowerPC 440EP和Linux在嵌入式和网络处理方面的优势,降低了网络延迟.本文中,介绍了采用SoC设计方法,实现一个独立的嵌入式多媒体流QoS监控器.     

嵌入式技术在煤矿井下排水系统中的应用

煤矿井下排水系统是煤矿安全生产的重要环节,传统的基于单片机的系统稳定性、可靠性较差.因此,将可靠性、实时性很高的嵌入式系统应用于煤矿井下排水系统中具有极强的现实意义.该系统实现了煤矿井下排水系统的基于嵌入式系统的网络接入,采用基于ARM处理器网络接口的硬件设计,以及μC/OS-Ⅱ嵌入式实时操作系统,并阐述了网络芯片应用中的几个技术问题.     

矿井无线传感器网络的网关设计

无线传感器网络在煤矿井下的推广和应用要求无线传感器网络和井下主干网络以太网进行互联,接入网关是关键部件。该文分析现有的无线传感器网络和以太网互联的通信实现方案,提出基于高性能网络处理器和嵌入式实时操作系统的网关解决方案,介绍基于嵌入式微处理器S3C4510B和嵌入式操作系统VxWorks实现矿井无线传感器网络接入网关的关键技术和具体方法。     

基于自适应QoS保证的多媒体监控系统模型研究

分析分多媒体监控特点,认为多媒体流的QoS保证是一个重要的研究课题。提出了支持自适应QoS保证的嵌入式IP网络多媒体监控系统模型。QoS保证方案包括系统资源监测,网络带宽的预估计,借助PID算法实现多媒体自适应流的自调节,以及音频优先保证。实验表明,该模型结构简单,制定的QoS控制策略能够实时地对视音频参数进行动态调整,资源利用率高,图像传输流畅。     

一种新型的基于IPTV网络的视频会话系统

基于IPTV网络的视频会话系统具有广阔的应用前景。研究并实现了一种基于IPTV网络的具有服务质量保证的新型视频会话系统,阐述了该系统的体系架构及业务流程,提出了适用于本视频会话系统的嵌入式IP机顶盒的体系架构,并针对嵌入式系统资源受限的特点进行了性能优化设计,特别提出了一种带宽自适应的QoS机制,充分保证视频会话应用在IPTV网络多业务环境下的用户体验。     

实时嵌入式环境中面向构件系统的QoS模型研究

将基于构件技术的开发引入到实时嵌入式软件平台能够很好地适应嵌入式领域多样性的特点,满足对软件开发效率和软件质量的要求。为保证实时嵌入式环境对资源动态变化的需求，考虑到系统资源的全局管理特性，仅从应用中增加QoS适应机制是不够的，还需在现有的构件框架中增加QoS管理机制。为此，提出了一种面向CCM构件系统的QoS模型，能够主动适应动态变化的资源状态，模型中层次式的QoS转换器的设计简化了用户对服务的QoS参数配置。     

嵌入式软件中一种修正QoS值的构件选择方法

CBSD(Component-Based Software Development)已经成为嵌入式软件开发的主流技术。在嵌入式环境下,有大量功能相似的构件,在开发过程中基于QoS的构件选择已成为研究热点。然而这些构件的QoS声明与提供者给出的往往并不一致。为此,提出一种基于修正QoS值的构件选择方法,该方法将QoS信任度作为权重,修正QoS值,再结合模糊逻辑,推理出该构件的综合服务能力。通过嵌入式VOD仿真实验,验证了算法的有效性,保证了构件选择的客观性和准确性。     

井下视频行人检测方法

针对现有基于深度学习的行人检测方法存在计算量较大、检测效率严重依赖硬件性能等问题,对基于SSD网络的行人检测方法进行改进,设计了一种基于DenseNet网络的轻量级卷积神经网络作为SSD网络的基础网络,以满足井下视频行人实时检测需求,并设计了基于ResNet网络的辅助网络,以增强特征表征能力,提高行人检测准确性。将基于改进SSD网络的井下视频行人检测方法部署在嵌入式平台Jetson TX2上进行实验,结果表明该方法对井下视频中行人的检测准确率为87.9%,针对井下行人低密度场景的检测准确率近100%,且运算速度达48帧/s,约为基于SSD网络的行人检测方法的4.4倍,满足井下行人实时检测需求。     

嵌入式无线局域网中H. 264视频传输的QoS研究

就H. 264在无线环境中的传输问题展开研究,针对嵌入式特点对现有的视频传输策略进行了改进,在服务这样可以将网络、缓冲和实时性等加以综合考虑,既保证了视频传输的实时性又提供了一定的网络QoS。且经过实验验证,这两种方法都取得了满意的效果。     

过程节点集群与网络实时QoS控制技术研究

利用互连网上的空闲资源实现非娱乐站点面向过程的信息集群,给出了涉及的实现原理与技术细节,并且有效地运用所有网络节点均具备的通用硬软件平台,按照嵌入式机制,大大提升了互连网的实时QoS和整体运营效率.     

Managing end-to-end QoS in distributed embedded applications

Maintaining end-to-end quality of service (QoS) is a challenge in distributed real time embedded systems due to dynamically changing network environments and resource requirements. The authors' middleware QoS management approach encapsulates QoS behaviors as software components. Using the Corba component model, they build these specialized QoS components and combine them to produce a comprehensive management system that maintains QoS. The authors illustrate the approach by building a real-world medium-scale system with these components. Using this example, they demonstrate the reusability of each component in different contexts.     

无线传感器网络基于模糊信息的QoS路由发现方法

有效使用片上受限资源以保持最长的生命周期是无线传感器网络的核心问题.无线传感器网络不断增长的多媒体应用引发人们研究如何满足具体应用的服务质量约束.能量因素与QoS各参数的相互影响构成了一个NP完全问题.本文引入模糊数学理论中的区间数概念抽象现实网络提供的信息,利用排队论方法将多业务多类型QoS多参数的约束和目标简化,从而得到了一种满足多类型业务多参数QoS要求的路由算法.仿真实验结果表明,在满足多类型业务多参数QoS要求的前提下,本文算法能很好支持多种业务的资源需求分配,可达到全网最优能耗均衡,延长网络寿命.     

Embedded fuzzy expert system for Adaptive Weighted Fair Queueing

This paper introduces an embedded fuzzy expert system for Adaptive Weighted Fair Queueing (AWFQ) located in the network traffic router to update weights for output queues. WFQ algorithm allows differentiated service for traffic classes according to Quality of Service (QoS) requirements. Link sharing and packet scheduling methods are the most critical factors when guaranteeing QoS. There are many different scheduling mechanisms but adequate and adaptive QoS aware scheduling solutions are still in a phase of development due to the rapid growth of multimedia in the Internet. The proposed AWFQ model in this work simplifies the link sharing to two service classes: one for UDP and another for TCP. The implementation of the model is based on adaptive change of weight coefficients that determine the amount of allowed bandwidth for the service class. New weight coefficients are calculated periodically on routers according to developed embedded fuzzy expert system. It is shown through simulations that the AWFQ model is more stable and reacts faster to different traffic states than the traditional WFQ scheduler. The embedded expert system adjusts the weights of AWFQ with two parameters that are based on the share of the UDP and TCP input traffic data rate and the change of the share of the UDP and TCP input data rate.     

Supporting end-to-end quality of service properties in OMG data distribution service publish/subscribe middleware over wide area networks

Assuring end-to-end quality-of-service (QoS) in distributed real-time and embedded (DRE) systems is hard due to the heterogeneity and scale of communication networks, transient behavior, and the lack of mechanisms that holistically schedule different resources end-to-end. This paper makes two contributions to research focusing on overcoming these problems in the context of wide area network (WAN)-based DRE applications that use the OMG Data Distribution Service (DDS) QoS-enabled publish/subscribe middleware. First, it provides an analytical approach to bound the delays incurred along the critical path in a typical DDS-based publish/subscribe stream, which helps ensure predictable end-to-end delays. Second, it presents the design and evaluation of a policy-driven framework called Velox. Velox combines multi-layer, standards-based technologies—including the OMG DDS and IP DiffServ—to support end-to-end QoS in heterogeneous networks and shield applications from the details of network QoS mechanisms by specifying per-flow QoS requirements. The results of empirical tests conducted using Velox show how combining DDS with DiffServ enhances the schedulability and predictability of DRE applications, improves data delivery over heterogeneous IP networks, and provides network-level differentiated performance.     

支持QoS的SIP代理服务器方案的设计与实现

从如何提高基于SIP协议的VoIP系统的语音质量出发,分析了该系统与MPLS技术结合处的难点,并提出了一种支持QoS的SIP代理服务器模型的解决方案。该方案的设计结构清晰、可扩展性强,解决了SIP代理服务器在IP网络中没有会话服务质量控制能力的问题,是一种好的融合VoIP及MPLS两大技术的应用模型。该方案目前已运用于基于嵌入式Linux平台的VoIP系统中,完全能够满足高质量语音的需求。     

Supporting SIP-based end-to-end Data Distribution Service QoS in WANs

Assuring end-to-end QoS in enterprise distributed real-time and embedded (DRE) systems is hard due to the heterogeneity and transient behavior of communication networks, the lack of integrated mechanisms that schedule communication and computing resources holistically, and the scalability limits of IP multicast in wide-area networks (WANs). This paper makes three contributions to research on overcoming these problems in the context of enterprise DRE systems that use the OMG Data Distribution Service (DDS) quality-of-service (QoS)-enabled publish/subscribe (pub/sub) middleware over WANs. First, it codifies the limitations of conventional DDS implementations deployed over WANs. Second, it describes a middleware component called Proxy DDS that bridges multiple, isolated DDS domains deployed over WANs. Third, it describes the NetQSIP framework that combines multi-layer, standards-based technologies including the OMG-DDS, Session Initiation Protocol (SIP), and IP DiffServ to support end-to-end QoS in a WAN and shield pub/sub applications from tedious and error-prone details of network QoS mechanisms. The results of experiments using Proxy DDS and NetQSIP show how combining DDS with SIP in DiffServ networks significantly improves dynamic resource reservation in WANs and provides effective end-to-end QoS management.     

Rapidio网络QoS多目标优化

针对现有Rapidio网络路由管理策略的缺点,提出了一种基于改进的遗传算法的优化策略。通过改进的路由分配策略以及对传统遗传算法编码、交叉和变异等方面的改进,明显提高了Rapidio网络服务质量（QoS）诸项指标;同时相对于传统遗传算法,改进的遗传算法拥有更快的收敛速度。该算法适用于基于Rapidio网络的嵌入式应用,具有较强的工程实用价值。