分布式视频编码在视频压缩中的应用

阐述了分布式视频编码的理论基础，即Slepian—Wolf无损源编码理论和Wyner-Ziv有损源编码理论，介绍了分布式视频编码技术在视频压缩中的应用，并对其中关键技术的最新研究进展进行了综述，最后给出了结论及今后的研究方向。     

网格编码调制与空时块码的级联和空时格码的比较

介绍了空时编码，阐述了正交空时分组编码的编解码过程及其与网格编码调制相结合的系统，并对空时分组编码、空时格栅编码、网格编码调制和空时分组编码级联这三者在相同的发送功率、相同的信息速率和相同的频带利用率的条件下的BER(误比特率)性能进行了比较，得出简单的网格编码调制和空时分组编码级联后的系统，可以比同复杂度甚至更高复杂度的空时格栅编码系统节省SNR(信噪比)。结论是针对两根发送天线和一根接收天线的，但对于更多天线的无线系统同样适用。     

MPEG-4自然视频编码技术

对MPEG－4自然视频编码的关键技术作了详细的分析和阐述。首先介绍MPEG－4频语法结构，并对视频编码的框架概要分析。接着分析了自然视频编码中涉及到的关键技术，包括：VOP的产生；二值和灰度级α平面的编码技术；运动估计和补偿方法；纹理编码；基于对象的时间分级和空间分级；MPEG－4提供的再同步和各种错误掩盖，刷新方法，精 编码技术和零树小波基的静止图像编码技术。指出MPEG－4和MPEG－1，MPEG－2等标准的异同，突出MPEG－4的三个主要特点。最后给出MPEG－4技术在网络视频传输中的应用，并给出测试和分析。     

数字电视编码及调制技术

从数字电视的系统组成入手，阐述了数字电视的压缩编码技术与标准，及数字电视传输技术，并对各国数字电视的制式标准进行了比较。     

图像压缩编码方法分析

介绍图像压缩编码技术发展过程,对图像压缩编码,特别是自适应预测编码、模型法编码、分形编码、小波变换压缩编码、神经网络压缩编码原理和特点进行分析,并阐述图像压缩编码的作用.     

网络视频编码技术

随着视频信息在网络上的应用需求的日益广泛和迫切,适合网络传输的视频编码技术成为了现在研究的一个热点,文章旨在综述网络视频编码技术的发展历程。详细介绍并对比了目前主要的网络视频编码技术:传统的视频编码技术在传输中的应用,视频的可扩展性编码以及视频的多描述编码,最后进一步阐述了未来网络视频编码技术可能的发展方向,分析了综合运用各种编码技术的可能。     

使用ISDN基本接口的可视电话

可视电话已成为热门领域，这是由于编码技术，ＶＬＳＩ、ＩＳＤＮ和标准化的发展，本文就ＩＳＤＮ可视电话和编码进行了阐述。     

数字音频编码及其应用

音频信号数字化后的数据量相当大，不利于传榆和存储，在日益广泛应用的数字技术中，数字音频的压缩成为其中的关键技术之一。介绍了频编码的模型及原理，分析了国内外现存的一些常用音频编码系统，并阐述了它们的性能特点以及实际中的应用。     

多描述编码及其视频应用

本介绍了多描述编码的编码模型，与分级编码的区别，并说明了多描述编码在视频领域中的应用及其优点。     

信源编码技术在广播电视信号数字化中的应用

介绍了编码的目的以及信源编码的原理,阐述了信源编码的功能。并介绍了实现音频、视频编码的方法,以及音频压缩编码和图像压缩编码的种类和标准。     

Development of embedded piezoelectric acoustic sensor array architecture

This paper examines development of novel piezoelectric acoustic sensors, which are capable of sensing high frequency acoustic emissions in a composite/metallic plate. The fabrication of the piezoelectric acoustic sensors, made from piezoceramic ribbons, is described in the paper. An attempt was made to build directionality into the sensing system itself. Continuous sensors placed at right angles on a plate are discussed as a new approach to measure and locate the source of the acoustic waves. Novel signal processing algorithms based on bio-inspired neural systems for spatial filtering of large numbers of embedded sensor arrays in laminated composite media are presented. It is expected that the present work would help in the development of microelectronic sensing aiding diagnostics and prognostics techniques for highly efficient health monitoring of integrated aerospace vehicles and structures.     

水声扩频信号发射机的研究

设计了大功率水声扩频信号发射机,该发射机具有调制方式多样,效率高,功率大,体积小等特点,并给出了发射机硬件的电路设计和软件控制程序实现过程。本扩频信号发射机采用ARM7 LPC2378作为主控芯片进行编码计算后输出扩频基带信号,采用直接数字式频率合成器(DDS)完成扩频信号的调制输出。根据全桥拓扑功率电路和绝缘栅双极性晶体管(IGBT)功率管的特点,设计了扩频信号发射机的功放输出电路。最后,对该扩频信号发射机的输出功率进行了实验验证,结果表明整机电路设计完全达到设计要求。     

Doppler effect in flexible and expandable light waveguide and development of new fiber-optic vibration/acoustic sensor

New principle and a geometrical arrangement of an optical fiber for a vibration/acoustic measurement are proposed in the present paper. The sensor is based on a new finding that a frequency of light wave transmitted through a bent optical fiber is shifted by vibration at the bent region. The phenomenon can be explained as Doppler's effect in flexible and expandable light waveguide. Several configurations of the sensor have been designed, and very high sensitivity is achieved in the extremely wide frequency range. Principle, sensor configuration and theoretical sensitivity, measurement system, and some experimental consideration are described in the present paper. The sensor sensitivity was examined experimentally in the low and middle frequency range, and the detectability was confirmed experimentally in the frequency range of acoustic emission signals.     

耳机的人机关系及声学设计

介绍了今后耳机的发展方向,阐述了耳机的人机关系,它关系到耳朵佩戴的舒适性.利用声学电路图详细说明了耳机的声学设计,以使对耳机腔体的设计有更深的了解,最后给出了耳机的声学参数和音质的关系.     

Underwater acoustic imaging

Underwater acoustic imaging systems are useful in providing underwater observation and inspection capabilities whenever optical systems cannot. Underwater acoustic imaging is a part of the larger field of acoustic imaging, and as such, has its own peculiarities and attributes as compared with the rest of the acoustic imaging field. In this report, the general characteristics of underwater acoustic imaging are presented. Three basic techniques of acoustic imaging that are appropriate for underwater imaging are discussed (focused, beamformed, and holographic) and examples of each of them are described. Then the limitations and promise for the future in underwater acoustic imaging are explored.     

特征关联编码对相似声目标学习记忆的影响

为了考察特征关联编码对相似声目标学习记忆的影响,对两组被试进行了相同任务的学习记忆实验.学习周期为13天,每天学习强度(声目标呈现次数)相同,学习结束后进行了遗忘测量,持续到第16天.对照组未采用任何特殊记忆方法,实验组在学习记忆任务时呈现听觉特征与数序关联编码信息.实验结果表明,实验组被试整体记忆饱和点出现较晚,且容量有显著提高,但记忆遗忘速率较大,不过保持量相对对照组更高.实验证明了听觉特征与数序关联编码能够提供有效的记忆编码信息,提升被试的学习记忆效率.     

Microwave Acoustic Devices for Pulse Compression Filters

The ability of devices based on the phenomena of magnetoelastic waves, acoustic bulk waves, acoustic surface waves, and the optoacoustic interaction to fulfill the requirements for a dispersive filter for a pulse compression RADAR are reviewed. The performance and current limitations of devices that use techniques employing these effects are described. The discussion is generally limited to devices which have been operated in the frequency range above 100 MHz. For comparison, other solid-state techniques that do not employ acoustic waves which can be used to make dispersive filter are described.     

声场设计应用

通过对厅堂建筑声学的分析,阐述了房间结构、装饰和室内声学的关系,以及在声学设计中为避免产生不合理因素而需处理的几个方面.通过实际设计举例,介绍了房间吸声的处理方法和影响房间声学指标的几个因素:把建筑声学和电声学结合在一起,通过计算举例,说明了二者的关系,以及如何进行室内楚声和电声的计算.     

Microwave Variable Delay Devices

Needs for nondispersive microwave variable delay devices exist in RADAR, communication, ECM, and test systems. Methods which have been investigated to satisfy these needs are reviewed in this paper. Techniques that employ solid-state microwave acoustic interactions and that have promise of satisfying some of the microwave variable delay requirements are described in detail, and their present capabilities and potential capabilities are discussed. One technique employing magnetoelastic waves is particularly promising and the state of the art of this technique is analyzed thoroughly.     

基于声表面波的微驱动技术的发展

基于声表面波技术近年来在微驱动技术领域快速发展的现状以及声表面波器件在生物、医疗、片上实验室等领域具有广阔应用前景的重要意义,就近几年来声表面波微驱动器的最新应用做了简要总结,介绍了声表面波,包括叉指换能器的结构和声表面波产生原理。着重介绍了声表面波在新型器件方面的多种最新应用,主要包括微流体加热、微流体雾化、微粒集聚/混合、微流体驱动、线性固体驱动以及平面固体驱动等,并分析了目前研究过程中存在的一些技术难点和解决方案。