一种实时以太网介质访问控制协议的时延性能分析

本文提出一种新的基于持续竞争的实时以太网介质访问控制协议,该协议能够保证实时信号的发送有确定的最大时延.在新协议下,如果检测到冲突,实时节点并不像普通以太网节点一样停止传输,而是坚持发送竞争信号,利用信道冲突通知非实时节点或者低优先级实时节点停止传输,把信道留给高优先级的实时节点.而且该协议与普通以太网介质访问控制协议兼容,这样实时节点与普通以太网节点能共存于同一网络系统中互相通信.文中详细描述了新型以太网介质访问控制协议,分析了实时信号的发送时延,理论分析和仿真均证明了该协议是可行和有效的.     

Kernel Thread Scheduling in Real‐Time Linux for Wearable Computers

In Linux, real‐time tasks are supported by separating real‐time task priorities from non‐real‐time task priorities. However, this separation of priority ranges may not be effective when real‐time tasks make the system calls that are taken care of by the kernel threads. Thus, Linux is considered a soft real‐time system. Moreover, kernel threads are configured to have static priorities for throughputs. The static assignment of priorities to kernel threads causes trouble for real‐time tasks when real‐time tasks require kernel threads to be invoked to handle the system calls because kernel threads do not discriminate between real‐time and non‐real‐time tasks. We present a dynamic kernel thread scheduling mechanism with weighted average priority inheritance protocol (PIP), a variation of the PIP. The scheduling algorithm assigns proper priorities to kernel threads at runtime by monitoring the activities of user‐level real‐time tasks. Experimental results show that the algorithms can greatly improve the unexpected execution latency of real‐time tasks.     

使用去调频宽带LFM信号的SAR实时成像处理

本文阐述了对采用去调频宽带LFM信号方法的SAR条带模式数据进行高分辨率实时成像的处理算法.与以前的实时处理不同之处在于:(1)距离向目标的回波信号经过了去调频处理;(2)要对距离单元迁移实时校正;(3)方位向单孔径实时连续成像.本文详细讨论了对SAR距离向去调频数据处理的原理和方法,提出适合实时处理的距离迁移校正的方法,并分析了整个实时处理流程的时限和计算量.实践证明本文的实时处理算法和流程是有效的.     

Real-time monitoring of cardiac regional function using fastHARP MRI and region-of-interest reconstruction

Cardiovascular stress test imaging assists in the diagnosis and monitoring of cardiovascular disease. The procedure can be carried out in a magnetic resonance (MR) scanner using pharmacological agents that mimic the effects of natural exercise. In order to provide real time indication of ischemia, thereby assisting in diagnosis and helping to assure patient safety, it is desirable to have real time monitoring of the myocardial regional function. This paper presents an algorithm for the real time myocardium region-of-interest reconstruction and myocardial strain computation using data acquired from a real time pulse sequence that has been previously reported. The chirp Fourier transform is used for efficient computation, enabling a real-time continuous strain map at a rate of 25 frames/s. Coupled with a real time data path from the scanner to a laptop computer, this algorithm enables real time continuous monitoring of cardiac strain and is targeted for use in the early detection and quantification of ischemia during MR stress tests.     

QoS‐based radio network dimensioning for LTE networks with heavy real‐time traffic

Applications of video streaming and real‐time gaming, which generate large amounts of real‐time traffic in the network, are expected to gain considerable popularity in Long Term Evolution networks. Maintaining the QoS such as packet delay, packet loss ratio, median, and cell border throughput requirements in networks dominated by real time traffic, is critical. The existing dimensioning methodology does not consider QoS parameters of real‐time traffic in network dimensioning. Moreover, exhaustive and time‐consuming simulations are normally required to evaluate the performance and QoS of real‐time services. To overcome this problem, we propose an improved radio network dimensioning framework that considers the QoS of real‐time traffic in network dimensioning. In this framework, an analytical model is proposed to evaluate the capacity and performance of real‐time traffic dominant Long Term Evolution networks. The proposed framework provides a fast and accurate means of finding the trade‐off between system load, packet delay, packet loss ratio, required median, and cell border throughput. It also provides network operators with an analytical means for obtaining the minimum number of sites required by jointly considering coverage, capacity and QoS requirements. The accuracy of the proposed model is validated through simulations. Copyright © 2012 John Wiley & Sons, Ltd.     

基于以太网的实时音频网络传输技术研究

应用数字网络技术,根据音频传输网络的要求,结合传统以太网技术,提出了实时传输BPA算法和N-Message的时钟同步算法,在网络数据链路层构造虚拟令牌,成功设计出了基于以太网的实时网络协议,较好地解决了音频实时传输的问题。     

空间目标光电探测控制与实时处理软件的设计

光电信息处理分系统是某天文台空间目标可见光光电探测系统的重要组成部分,本文针对该分系统控制复杂、CCD图像处理算法实时性要求高等特点,着重描述了该系统中的控制与实时处理软件的设计方法以及实现途径.本文简要介绍了控制与实时处理子系统的硬件结构和它在分系统中的地位和作用,描述了控制与实时处理子系统的软件系统组成和实现方法,并讨论了软件系统中的实时处理算法及实现.该软件系统已经成功应用到空间目标可见光光电探测系统中,实践结果表明,软件系统设计合理,算法软件实时有效.     

基于嵌入式实时操作系统uc/os-II的数据采集系统的设计

主要介绍了基于嵌入式实时操作系统uc/os II的单片机数据采集系统的设计。该系统比传统的数据采集系统具有更好的安全性和实时性。并可应用在实时图像监控等复杂系统中。     

一种基于信号机制在UNIX实时应用中快速传递信息的方法

在多进程的实时应用程序中,进程之间往往需要通过传递一些信息来达到资源共享的目的。介绍了一种基于信号机制在UNIX实时应用中的两个进程之间实现快速传递信息的方法,提高了实时性。     

基于异构多核处理器的实时红外人体目标检测技术

红外实时人体目标检测因无需主动光源、易于去除环境干扰等优点成为近年来人工智能领域的一个研究热点。当前主流实时红外嵌入式图像采集处理方式因图像传输、接口速度、工程量等技术局限,制约了红外人体目标检测的便捷实现和实时利用。针对传统嵌入式处理器难以同时采集和处理红外数据这一影响红外人体目标检测实时性的技术问题,研究了基于ZYNQ异构多核处理器的实时检测技术。采用FPGA+多核ARM架构,由FPGA端实现人体红外图像的VDMA采集、预处理及显示,由多核ARM端完成HOG-SVM算法处理,并使用TBB进行加速。实验结果表明:该技术能够完成人体目标的实时有效检测,兼具功耗低、开发简单、实用性强和集成度高等优点。     

RTX 在激光制导炸弹半实物仿真中的应用

三轴仿真转台是激光制导炸弹导引头半实物仿真系统中的关键设备之一, 针对高精度三轴仿真转台实时控制的要求, 讨论了基于RTX 的实时控制系统的设计和实现方法, 介绍了RTX 的实时特征, 对Windows- NT 系统和RTX 实时操作系统在实时精度方面的性能进行了比较。并给出弹道跟踪曲线等实验结果。实验证明, 该系统实时性高, 工作稳定可靠。     

实时时钟芯片DS1302在DSP嵌入式系统中的应用

在许多嵌入式应用场合需要实时时钟的功能,通常DSP（数字信号处理器）芯片并不具备此功能,因此在实际使用过程中需要外扩实时时钟芯片来解决该问题。文中介绍了串行时钟芯片DS1302的功能以及在DSP嵌入式实时处理系统中的应用,给出了基于CPLD（复杂可编程逻辑器件）的控制器逻辑设计和DSP底层软件驱动编写的方法,指出了逻辑设计中需要注意的问题。实现一种分层、高效和可移植的嵌入式系统。经过长期的试验．实时时钟运行稳定准确,取得了良好的效果。     

一种实用广角成像系统几何畸变数字实时校正方法

图像的几何畸变广泛存在于应用广角镜头的成像系统,畸变的存在尤其不利于基于图像分析的定量分析领域。针对一个基于图像分析的红外角位置测量系统,提出一种实用广角成像系统几何畸变数字实时校正方法,阐述其畸变参数的标定方法,图像的空间变换和灰度插值方法,基于实时性要求,给出畸变校正的算法步骤,实验表明,此广角成像系统几何畸变数字实时校正方法有效提高了角位置测量系统的测量精度,并具有一定的实时性能。     

An integrated routing and admission control mechanism for real‐time multicast connection establishment

There are two major difficulties in real‐time multicast connection setup. One is the design of an efficient distributed routing algorithm which optimizes the network cost of routing trees under the real‐time constraints. The other is the integration of routing with admission control into one single phase of operations. This paper presents a real‐time multicast connection setup mechanism, which integrates multicast routing with real‐time admission control. The proposed mechanism performs the real‐time admission tests on a cost optimal tree (COT) and a shortest path tree (SPT) in parallel, aiming at optimizing network cost of the routing tree under real‐time constraints. It has the following important features: (1) it is fully distributed; (2) it achieves sub‐optimal network cost of routing trees; (3) it takes less time and less network messages for a connection setup. Copyright © 2001 John Wiley & Sons, Ltd.     

复值核结构元数学形态学二值图像实时光学并行处理

用光学实时并行图像处理与计算机的灵活特性相结合可实现数学形态学实时并行图像处理。提出了采用实时光学处理系统和复值核结构元光学频域滤波方法实现二值图像数学形态学实时并行处理     

一种实时数据流认证方案

数据源认证是信息安全体系中的重要部分,在实时数据流的认证过程中,认证速度和效率是两项重要指标。文章在数字摘要和数字签名技术的基础上,根据实时数据流的传输特点,设计了一种并行处理的实时数据流认证方案,并从传输密度和认证窗口两方面进行了性能分析。这一方案提高了实时阶段的效率,适合于在不安全网络上对实时数据流进行认证。     

A Novel Effective Bandwidth Based Call Admission Control for Multimedia CDMA Systems

A novel Call Admission Control(CAC)scheme is proposed for multimedia CDMA systems.The effectivebandwidth of real time calls is reserved in the CAC with the consideration of active factors.The admission of non-real timecalls is controlled by the system according to the residual effective bandwidth left from real time calls.Simulation resultshave shown that the novel CAC has greatly enlarged the admission region for real time calls and make the transmission de-lay of non-real time calls under an acceptable level.     

空间载波相移法用于全息CT测量气体温度场

为了能从干涉图像中快速识别相位,将空间载波相移法用于实时全息检测,以电热丝周围的气体为研究对象,采用单次曝光法作了实时全息实验,获得两种干涉图像,结合全息CT技术,均得到了待测气体的温度场.研究结果经比较表明,该方法在实时全息干涉测量中,不但可行,而且准确度高,便于实际应用.     

Real time infrared image processing

The paper studies the techniques of real time infrared image processing. The enhancement of real time infrared image is mainly discussed. With enhancement of real time infrared image, the authors suggest main methods that are local histogram equalization, pseudo color display, average of multiple frames and accumulation of multiple fields, contour enhancement and restoration coefficient. Empasis is laid on the restoration coefficient method, in this paper. On the basis of describing the model of the method, the conerete project for realizing enhancement of the real time infrared image is put forward, and the practical example is given.     

联机采集与联机采集技术

电信业务量的变大使得要采集的数据量也越来越大,手工采集和按月计费处理已经无法适应竞争的要求。联机采集系统与交换机直接连接,实时采集交换机生成的计费原始话单,并将其标准化后送往本地计费帐务中心,是新一代电信实时计费帐务系统的基础。分析了联机采集的作用和意义,介绍了联机采集的前置采集和集中采集组网方式。联机采集系统的实现是计费帐务和营业受理完全实时化的关键一步,它将使电信行业的计费帐务和营业受理推到实时处理的新的高度。