人机交互中的声源定位与增强方法

基于人机交互的实际应用场景,提出了一种交互目标声源三维定位与语音增强算法。该算法首先在广义相关法的基础上提出一种声达时延差的估计方法,通过由6个麦克风构成的平行均匀线阵接收模型,实现对目标声源的三维定位;然后在交互目标声源定位的基础上,通过调整时延波束叠加的权值,实现对目标语音的增强。仿真实验结果表明,文中提出的算法能够准确定位目标声源并对目标语音进行有效增强。在信噪比大于1.5 dB 的环境中,该算法可使目标声源达到98%以上定位精度,5 dB 以上信噪比改善,同时算法运算量小且易于硬件实现。     

欠定条件下弱稀疏源信号混合矩阵盲估计

针对源信号的稀疏性影响欠定混合矩阵的估计精度, 在源信号单源频率及非单源频率分量分析的基础上,通过对观测信号频率峰值的幅值比值所 构成的列向量聚类,提出欠定条件下弱稀疏源信号混合矩阵的盲估计方法。鉴于经典聚类算 法的局部收敛性带来聚类结果的不稳定性,采用全局收敛特性较好的遗传模拟退火聚类算法 提高聚类结果的鲁棒性。仿真实验表明,本文提出的混合矩阵估计方法及采用的聚类算法 在不同欠定条件及噪声环境下具有较强的估计性能。     

室内装修的环境污染及其预防探讨

介绍了室内环境污染的来源、装修材料的污染性,探讨了造成室内环境污染的因素,并在此基础上提出了一系列新型环保节能的建筑材料和室内装修污染的防治措施。     

东山煤矿“三下采煤”应用经验

概述了东山煤矿“三下采煤”技术发展现状、工艺流程、技术要求及发展过程中遇到的难点问题,并对“三下采煤”技术给东山煤矿带来的经济效益和社会效益进行了分析。     

Sparkle measurement revisited: A closer look at the details

Four years after introduction of the first instrument for measurement of sparkle, the foundations have been reconsidered, and the pool of practical experience has been analyzed to provide a more detailed and complete picture of the subject matter. The following aspects are introduced and discussed: observation conditions and resulting requirements for imaging (sampling) and filtering, analysis of spatial periods and frequencies as a basis for filtering, spatial filtering concepts, sparkle in the frequency domain, sparkle evaluation based on analysis of single images and difference images, origins of unwanted sparkle components, scaling and offset in sparkle evaluation, and verification of the method.     

基于PCI和RS-422的隔离多路信号源与上位机通信的设计与实现

设计了基于PCI总线和RS-422的隔离多路信号源,PCI9054搭建起PCI接口电路,采用分片、分帧的乒乓数据传输结构完成数据的传输;该数据传输方式具有通用性强、操作灵活、升级和扩展能力强等优点;重点分析了上位机与测试台的PCI通信协议,乒乓数据结构及测试台内部板卡间的RS-422通信方式,并调试其与上位机通信;实验测试证明,与传统方式相比,数据准确性和稳定性明显提高,能以86MBps的速率进行数据传输。     

噪声系数的测量方法研究

该文介绍了三种测量噪声系数的方法：增益法,Y因子法和冷源法。重点介绍了当我们做精确测量时Y因子法的不足和冷源法的突破以及给出了这两种方法的实际测试例子。     

On the use of open-source firewalls in ICS/SCADA systems

ABSTRACT

Firewalls are one of the most widely used security devices to protect a communications network. They help secure it by blocking unwanted traffic from entering or leaving the protected network. Several commercial vendors have extended their firewall capabilities to support SCADA protocols or designed SCADA-specific firewalls. Although open-source firewalls are used successfully in IT networks, their use in SCADA networks has not been properly investigated. In this research we investigate the major open-source firewalls for their use in SCADA networks and identify Linux iptables’ potential as an effective SCADA firewall. Iptables is a powerful open-source firewall solution available as part of most Linux distributions in use today. In general, use of iptables as a network-level firewall for SCADA systems has been limited to basic port and host filtering, without further inspection of control messages. We propose and demonstrate a novel methodology to use iptables as an effective firewall for SCADA systems. This is achieved by utilizing advanced iptables features that allow for dynamic inspection of packet data. It is noteworthy to mention that the proposed solution does not require any modification to the netfilter/iptables framework, making it possible to turn a Linux system into an effective SCADA firewall. The approach has been tested by defining filtering rules for the Modbus TCP protocol and validating its ability to defend against various attacks on the protocol.     

基于物联网的辐射源安全监管系统的设计与实现

辐射源具有强烈的社会敏感性,无论是丢弃还是泄漏,都会给人类社会和环境造成无法估量的损失和危害。为了使其能够进一步造福于人类社会,对辐射源进行规范使用,安全监管尤为重要。文章介绍了一套集辐射源剂量监测、RFID电子标签、GPS地球定位、位移检测、视频监控和管理为一体的安全监管物联网应用系统,以降低辐射源被盗的风险,准确高效地实现辐射源安全监管的目标。     

Using the World Wide Web for Art and Humanities Reference Services

Abstract

This paper describes what the World Wide Web is and what is needed in order to access its information. It discusses the future of art and humanities reference resources and presents criteria for evaluating Web sites. A review of the literature related to “Generation X” and their information expectations was done. There is an annotated list of specific World Wide Web resources related to African Diaspora, American Poetry, Comparative Literature, Gay and Lesbian Literature, and Outsider Art. This list provides examples for evaluation and is not meant to be exhaustive.