General approach to efficient implementation of 2-D denominator-separable digital transfer functions

A functional theoretical framework is reported for obtaining efficient 2-D digital filter realisations. A given 2-D transfer function having a separable denominator polynomial is developed into certain expansions which may be realised as two-stage structures. In such structures, only suitable 1-D substructures need to be searched for to obtain a complete realisation by connecting 1-D substructures using the corresponding weighting matrix.<>     

A language-based approach to protocol implementation

Morpheus is a special-purpose programming language that facilitates the efficient implementation of communication protocols. Protocols are divided into three categories, called shapes, so that they can inherit code and data structures based on their category. The programmer implements a particular protocol by refining the inherited structure. Morpheus optimization techniques reduce per-layer overhead on time-critical operations to a few assembler instructions even though the protocol stack is not determined until run time. This supports divide-and-conquer simplification of the programming task by minimizing the penalty for decomposing complex protocols into combinations of simpler protocols     

A multimedia synchronization model and its implementation intransport protocols

An implementation of a synchronization mechanism in transport protocol to support multimedia applications over a packet or cell switched network is proposed. In designing such a mechanism for practical use, ease of implementation and capability of handling random delay of packets are two key issues for success. Since the random delay of packet or cell switched networks makes synchronization among media more complicated after the transmission across the network, a model which considers the random transmission delay is hence required to specify the temporal relationship among media. Therefore, a real-time synchronization model is presented to satisfy this requirement in the paper. Based on the proposed synchronization model, a transport protocol, namely the multimedia synchronization transport protocol (MSTP), is designed and implemented. We have implemented a prototype system using the MSTP protocol and built a simulation system for the wide area network (WAN) environment in order to evaluate the performance of the MSTP protocol     

A joint signal processing and cryptographic approach to multimedia encryption.

In recent years, there has been an increasing trend for multimedia applications to use delegate service providers for content distribution, archiving, search, and retrieval. These delegate services have brought new challenges to the protection of multimedia content confidentiality. This paper discusses the importance and feasibility of applying a joint signal processing and cryptographic approach to multimedia encryption, in order to address the access control issues unique to multimedia applications. We propose two atomic encryption operations that can preserve standard compliance and are friendly to delegate processing. Quantitative analysis for these operations is presented to demonstrate that a good tradeoff can be made between security and bitrate overhead. In assisting the design and evaluation of media security systems, we also propose a set of multimedia-oriented security scores to quantify the security against approximation attacks and to complement the existing notion of generic data security. Using video as an example, we present a systematic study on how to strategically integrate different atomic operations to build a video encryption system. The resulting system can provide superior performance over both generic encryption and its simple adaptation to video in terms of a joint consideration of security, bitrate overhead, and friendliness to delegate processing.     

A computationally efficient two-step implementation of the GLRT

In this paper, the performance of a new two-step adaptive detection algorithm is analyzed. The two-step GLRT consists of an initial adaptive matched filter (AMF) test followed by a generalized likelihood ratio test (GLRT). Analytical expressions are provided for the probability of false alarm (P_FA) and the probability of detection (P_D) in unknown complex Gaussian interference. The analysis shows that the two-step GLRT significantly reduces the computational load over the GLRT while maintaining detection and sidelobe rejection performance commensurate with the GLRT. The two-step GLRT detection algorithm is also compared with another two-step detection algorithm: the adaptive sidelobe blanker (ASB). Both the two-step GLRT and the ASB are characterized in terms of the mainbeam detection performance and the rejection of sidelobe targets. We demonstrate that for a given P_FA, the two-step GLRT has a broad range of threshold pairs (one threshold for the AMF test and one for the GLRT) that provide performance identical to the GLRT. This is in contrast with the ASB, where the threshold pairs that maximize the P_D are a function of the target's signal-to-interference-plus-noise ratio (SINR). Hence, for a fixed pair of thresholds, the two-step GLRT can provide slightly better mainbeam detection performance than the ASB in the transition region from low to high detection probabilities     

A modular approach to the communication protocol and standard for multimedia information: A review

The paper focuses on a modular approach to design of a communication protocol and an MPEG-like standard for multimedia information processing. Generally, the following basic problems can be considered: (i) selection, (ii) composition, and (iii) combinatorial evolution and forecasting. Here, the composition problem is examined. The ZigBee Protocol for wireless sensor networks is studied as an example for the modular design. A generalized MPEG-like standard is considered as a representative example as well. Morphological (modular) system design is used for composition of the elements (components) of the protocol/standard. The solving process is based on Hierarchical Morphological Multicriteria Design (HMMD): (i) multicriteria selection of alternatives for system components, (ii) synthesis of the selected alternatives into a resultant combination. Numerical examples illustrate the design process.     

A common systems approach to emergency medical communications

An effective communications capability is an absolute necessity to the success of any emergency medical services system. This paper discusses the common systems approach adopted in Docket 19880 as the most effective way to provide for today's medical communications requirements.     

A unified approach to the real-time implementation ofmicroprocessor-based PWM waveforms

A method for real-time implementation of any two-level three-phase pulse-width-modulator (PWM) invertor waveform is discussed. The hardware and software of the scheme are built around the 16 b 8086 microprocessor and its peripherals, with a few additional digital ICs. The suggested scheme realizes the PWM waveforms without harmonic distortion. The implementation procedure is a universal one and it generates in real time any two-level three-phase PWM waveform with the chosen hardware structure. There is no need for hardware alteration for realization of different types of PWM waveforms     

An interactive and team approach to multimedia design curriculum

Over the past decade, increasingly powerful technologies have made it easier to compress, distribute, and store multimedia content. The merger of computing and communications has created a ubiquitous infrastructure that brings digital multimedia closer to the users and opens up tremendous educational and commercial opportunities in multimedia content creation, delivery, rendering, and archiving for millions of users worldwide. Multimedia has become a basic skill demanded by an increasing number of potential jobs for electrical engineering/computer science graduates. In this article, the authors intend to share their experiences and new ways of thinking about curriculum development. It is beneficial for colleagues in the multimedia signal processing areas for use in developing or revising the curriculum to fit the needs and resources of their own programs.     

多媒体互动展示系统的设计与实现

文章设计了多媒体互助展示系统。首先对系统的需求进行了分析;设计了系统的硬件系统和软件系统,最后设计了数据库,该系统的实现采用Windows 2007 Advaneed Server+11S 6.0+ASP.NET+Microsoft SQL Server 2008平台。     

The design and implementation of an operating system to supportdistributed multimedia applications

Support for multimedia applications by general purpose computing platforms has been the subject of considerable research. Much of this work is based on an evolutionary strategy in which small changes to existing systems are made. The approach adopted is to start ab initio with no backward compatibility constraints. This leads to a novel structure for an operating system. The structure aims to decouple applications from one another and to provide multiplexing of all resources, not just the CPU, at a low level. The motivation for this structure, a design based on the structure, and its implementation on a number of hardware platforms is described     

A new approach to designing computationally efficient interpolatedFIR filters

More efficient use of multipliers in FIR filters can be achieved at the expense of a slight increase in delay by designing sparse filter structures. We have developed a new, relatively simple approach to designing sparse cascaded filters, also described in the literature as interpolated FIR filters. Our method is heuristic in nature, but gives surprisingly good results without requiring iterative design or investigation of a large number of alternative parameterizations. The design uses the efficient and widely available Remez exchange algorithm along with some routines that we have written for Matlab. Although the resulting designs are not optimal in a minimax-error sense, they have reduced RMS error, which may be attractive for some applications. We give design examples, and study the effects of coefficient quantization     

A new efficient expression generation and automatic cloning method for multimedia actors

This paper describes a new and efficient method for facial expression generation on cloned synthetic head models. The system uses abstract facial muscles called action units (AUs) based on both anatomical muscles and the facial action coding system. The facial expression generation method has real-time performance, is less computationally expensive than physically based models, and has greater anatomical correspondence than rational free-form deformation or spline-based, techniques. Automatic cloning of a real human head is done by adapting a generic facial and head mesh to Cyberware laser scanned data. The conformation of the generic head to the individual data and the fitting of texture onto it are based on a fully automatic feature extraction procedure. Individual facial animation parameters are also automatically estimated during the conformation process. The entire animation system is hierarchical; emotions and visemes (the visual mouth shapes that occur during speech) are defined in terms of the AUs, and higher-level gestures are defined in terms of AUs, emotions, and visemes as well as the temporal relationships between them. The main emphasis of the paper is on the abstract muscle model, along with limited discussion on the automatic cloning process and higher-level animation control aspects.     

论广播中心的播出系统备份应急方案

播出系统备份应急方案主要由三部分组成,即直播室系统、总控室系统、音频工作站系统.备份应急系统的作用就是在播出系统出故障时能紧急启动,并解说如何通过故障判断启动相应的应急预案.     

职业院校课堂中如何巧妙运用多媒体教学

多媒体教学的最大优势就是生动形象,更加直观,最大化的提高教学效果。采用多媒体教学能够促进学生对专业知识的掌握程度,同时能够对培养学生的实践能力起到辅助作用,因此多媒体教学被广泛运用到职业院校课堂的教学中。但是在职业教育中,如何运用现代技术发挥职业教育的优势依旧存在着一些问题和弊端,本文通过对职业院校课堂多媒体教学存在的问题进行分析,研究解决这些问题的对策,用更巧妙的方式在职业院校课堂中运用多媒体教学。     

EPON无线接入多媒体终端的设计与实现

EPON(以太网无源光网络)作为具有广阔应用前景的光纤接入网技术已经越来越多地应用于接入网系统中.文章提出将WLAN(无线局域网)技术与EPON系统相结合,实现EPON系统的无线接入服务.通过对这两种技术相结合的可行性的理论分析,对所提出系统的架构进行了描述,并通过系统测试验证了所提出系统的可行性和有效性.     

智能化远程多媒体体育教学系统的设计与实现

在如今这个科学技术发展迅速的时代,远程教学及多媒体教学已经广泛应用于各个学科的教学中去,并且也获得了显著成效。近些年来,智能化远程多媒体教学方式越来越广泛地应用到教学中,但是该技术还处于发展阶段,存在着一定的不足和缺陷,但是智能化远程多媒体体育教学系统确实为教师和学生提供了很大帮助,同时也激发了学生学习体育的兴趣。本文首先对智能化远程多媒体体育教学系统的设计准则进行概述,并对智能化远程多媒体教学在体育课程中的应用进行简要分析,阐述了智能化远程多媒体体育教学系统的需求,最后针对系统需求进行设计和实现。     

基于ARM-Linux多媒体播放器的设计与实现

针对目前大多数多媒体播放系统都需要通过专门的视频编解码芯片对视频文件进行编解码,所带来的成本高、开发繁琐等问题,结合ARM微处理器、嵌入式Linux操作系统、MPlayer应用程序等,设计一种基于ARM-Linux的嵌入式多媒体播放系统。该系统采用了低成本、低功耗、高性能的ARM处理器,嵌入了开源、移植性高,功能强大的Linux操作系统。同时使用了网络文件系统NFS,实现不同操作平台上的文件共享。最终在该嵌入式系统下,通过经移植的应用程序MPlayer将音视频文件直接经软解码后实现了多媒体播放器的功能,播放音画质流畅稳定,达到预期效果。结果表明,该设计不仅降低了成本,且简化了开发的过程。     

A flexible middleware for multimedia communication: design,implementation, and experience

Distributed multimedia applications require a variety of communication services. These services and different application requirements have to be provided and supported within: (1) end-systems in an efficient and integrated manner, combining the precise specification of quality-of-service (QoS) requirements, application interfaces, multicast support, and security features and (2) the network. The Da CaPo++ system presented in this paper provides an efficient end-system middleware for multimedia applications, capable of handling various types of applications in a modular fashion. Application needs and communication demands are specified by values in terms of QoS attributes and functional properties, such as encryption requirements or multicast support. Da CaPo++ automatically configures suitable communication protocols, provides for an efficient runtime support, and offers an easy-to-use, object-oriented application programming interface. While its applicability to real-life applications was shown by prototype implementations, performance evaluations have been carried out yielding practical experiences and numerical results