Gossip-based ad hoc routing

Many ad hoc routing protocols are based on some variant of flooding. Despite various optimizations of flooding, many routing messages are propagated unnecessarily. We propose a gossiping-based approach, where each node forwards a message with some probability, to reduce the overhead of the routing protocols. Gossiping exhibits bimodal behavior in sufficiently large networks: in some executions, the gossip dies out quickly and hardly any node gets the message; in the remaining executions, a substantial fraction of the nodes gets the message. The fraction of executions in which most nodes get the message depends on the gossiping probability and the topology of the network. In the networks we have considered, using gossiping probability between 0.6 and 0.8 suffices to ensure that almost every node gets the message in almost every execution. For large networks, this simple gossiping protocol uses up to 35% fewer messages than flooding, with improved performance. Gossiping can also be combined with various optimizations of flooding to yield further benefits. Simulations show that adding gossiping to AODV results in significant performance improvement, even in networks as small as 150 nodes. Our results suggest that the improvement should be even more significant in larger networks.     

Combined and iterative form of spatial and temporal error concealment for video signals

Video transmission over unreliable channels may suffer from the data loss or corruption. To facilitate the transmission, video content is compressed to save the bandwidth. The compression algorithms remove the redundancies in the video signal, meanwhile increasing the dependencies among symbols in the compressed bit-stream. Thus, when errors occur, they may propagate in both space and time. Among various error control techniques, error concealment (EC) is an effective method that is performed at the decoder to mitigate the influence of errors on the quality of reconstructed images. In this paper, a joint spatial and temporal EC algorithm (JSTEC) is presented. First, several existing temporal EC algorithms are combined in an appropriate order. Then, the spatial correlation in the video is exploited in an iterative form to improve the performance of the temporal EC. Experimental results show that JSTEC performs better both in peak signal-to-noise ratio and subjective quality of images than the existing algorithms.     

Low complexity iterative decoding for bit-interleaved coded modulation

Bit-interleaved coded modulation with iterative decoding (ID) is an effective scheme for both AWGN and fading channels because it simultaneously realizes large Euclidean distance and high diversity. In the literature, ID schemes with hard-decision feedback (HDF), as well as soft-decision feedback (SDF), have been investigated. While HDF/ID exhibits a performance inferior to SDF/ID, it is much simpler to implement. To enhance the performance of HDF/ID with moderate additional complexity, we propose a uniform soft-decision feedback ID (USF/ID) scheme. The proposed scheme is applicable in both single antenna and multiple antenna communication systems. The simulation results verify that it achieves impressive performance gain over HDF/ID and has a practically more attractive implementation than SDF/ID, especially for complexity-constrained wireless applications.     

汽车变速箱性能检测系统设计与实现

本文从整体上论述了汽车变速箱性能检测系统的测试原理和设计方案,并从硬件和软件两方面详细阐述了汽车变速箱性能检测系统的组成。现场总线的采用,使本系统的结构更加简单,实施更加方便。实践证明,该方法是可行的,可靠的。     

基于MATLAB的控制器设计研究

文章首先对MATLAB软件作了简要的介绍,强调了它目前在各个领域中都得到了广泛的应用。接着总结了控制系统校正的主要方法,包括串联校正和反馈校正等。最后结合两个具体的例子,给出了利用MATLAB设计出不同的控制器的方法。     

多线程技术在嵌入式数据采集系统中的应用

讨论了多线程技术在嵌入式数据采集系统中的应用，给出了PC机与嵌入式计算机系统的多线程串行通信的实现。     

基于自适应模糊控制器的氧枪冷却水系统

针对炼钢厂水站系统中的氧枪枪位控制，设计了一种自适应模糊控制器。根据控制器输出误差在线调整参数，并按照氧枪枪位随流量变化的规律进行连续调节，给出相应的自适应算法。以实时修正模糊规则。从而确定了每一炉各个阶段氧枪的基本枪位，改变了原系统水泵长期伞速运行造成严重能耗损失的状况。仿真结果表明：自适应模糊控制器能适应流量的变化，使氧枪枪位在整个炉役期都能处于最优的位置，改善了系统性能。     

基于语义激活的智能图形处理系统

全面分析了目前知识处理系统所存在的弊病,提出了下一代语义激活系统,探讨了新一代知识系统所应提供的服务;并将之运用于图形处理系统,阐明了图形数据从统一表示到有效存储、建模、再现和检索等一系列智能处理过程;进而提出了图形信息的语义表示和智能推理模型.     

基于小波分析方法的装备价格指数变化研究

针对传统时间序列方法对物价指数的非平稳现象适应性较差的问题,提出运用小波分析方法,将原始数据分解成不同频率段的平稳信号,进而采用传统方法进行处理,从而提高了预测精度,获得令人满意的效果。     

经济型网络化数控系统的开发与应用

文中介绍了基于工业PC和专用DSP运动控制技术的经济型网络化开放式数控系统。在WINDOWS平台下,利用PC丰富成熟的资源和专用DSPMCX314AS强大的运动控制功能,并使用VisualC++和COM技术开发系统软件和API,最终形成多功能、低价格、高性能、简单、可靠、具有多轴多通道控制能力,丰富的标准接口,可配套使用多种伺服驱动单元和真彩色液晶显示器,连接以太网络通信、同CAD/CAM及管理系统互动的数控系统产品。该系统已成功应用于对立式铣床X8126的改造。