一种多媒体通信机制的实现

分布式多媒体信息点播系统DMIoDS(Distribut-ed Multimedia Information on Demand Systems)是对VoD系统的扩充,可以满足人们对包括视频在内的各种各样的信息的点播需求。为了支持DMIoDS系统的设计与实现,我们提出并且实现了一种多媒体通信机制——服务质量受控型管道QCPIPE(Quality-     

一种分布多媒体信息点播系统模型

分布式多媒体信息点播系统ＤＭＩｏＤＳ作为对ＶｏＤ系统的一种扩展。已经成为我媒体信息处理技术中的一个新的应用领域。本从分析ＤＭＩｏＤＳ的几个特点出发，提出了种ＤＭＩｏＤＳ的抽象功能层次模型，依据这个抽象模型，给出了一个原型系统，并对原型作了实现。     

网构软件数据语用的一种动态支撑方法

网构软件不确定的数据需求导致了其数据语用(data pragmatics,简称DP)的不确定性,进而要求数据语用的支撑机制具备动态适应能力,即应用的对象属性与数据表之间的对应关系可以按需动态地创建、更新、删除.针对当前持久化技术缺乏数据语用的动态适应性问题,提出了一种基于对象/关系映射的数据语用动态支撑方法POD(persistence on demand),并且在主流ORM(object/relational mapping)框架的基础上实现了一个遵循POD的持久化框架的原型系统.     

基于RTSP和DVB-C协议的VOD系统的实现

视频点播VOD(Video On Demand)是一种交互式多媒体信息点播系统,其本质是信息使用者可根据自己的需求主动获取多媒体信息.视频点播的网络选择与方案实现是目前VOD系统实现的技术关键和主要研究方向.基于RTSP和DVB-C协议可在现有互联网和HFC网(数字电视广播网)基础上构建一个易于管理、效果流畅、功能完善的VOD系统.     

商业导购多媒体信息系统的设计与实现

本文以研制一个商业导购多媒体信息系统为例，讨论了基于FoxPro for Windows系统开发多媒体信息系统的技术和方法。内容包括：结合地理信息平台（MapInfo）的地图查询，通用逐级过滤查询，文本显示处理，MPEG、MI－DI、Sound等多媒体信息处理技术。     

一种多媒体通信机制--服务质量受控型管道

提出一种多媒体通信机制--服务质量受控型管道,作为基于服务质量的平台层点对点多媒体通信抽象,以支持分布式多媒体应用的描述与开发.给出了服务质量受控型管道的形式定义,详细讨论了其工作过程.该抽象已经成功地应用于分布式多媒体信息点播系统和分布式多媒体信息系统等.实践表明,服务质量受控型管道既可以直接支持点对点多媒体通信,也可以作为多媒体组通信抽象的基础.     

Analyzing Effect of Demand Rate on Safety of Systems with Periodic Proof-tests

Quantitative safety assessment of safety systems plays an important role in decision making at all stages of system lifecycle, i.e.,design,deployment and phase out.Most safety assessment methods consider only system parameters,such as configuration,hazard rate,coverage,repair rate,etc.along with periodic proof-tests (or inspection).Not considering demand rate will give a pessimistic safety estimate for an application with low demand rate such as nuclear power plants,chemical plants,etc.In this paper,a basic model of IEC 61508 is used.The basic model is extended to incorporate process demand and behavior of electronic- and/or computer-based system following diagnosis or proof-test.A new safety index,probability of failure on actual demand (PFAD) based on extended model and demand rate is proposed.Periodic proof-test makes the model semi-Markovian,so a piece-wise continuous time Markov chain (CTMC) based method is used to derive mean state probabilities of elementary or aggregated state.Method to determine probability of failure on demand (PFD) (IEC 61508) and PFAD based on these state probabilities are described.In example,safety indices of PFD and PFAD are compared.     

一种开源软核OR1200的系统级描述方法研究

探讨了一种基于ADL(体系结构描述语言)的系统级设计方法,并以一款32位嵌入式开源软核OpenRISC1200为原型,采用系统级的ADL—SystemC语言对这款软核从体系结构角度进行系统级抽象,主要实现了OR1200CPU模块的描述,并通过嵌入式逻辑分析仪SignalTap II对系统进行验证。     

市场观象

IBM on-demand进入实施期 近日,IBM公司e-business on demand部门总经理Wladawsky-Berger博士访华,向业界介绍了全球开始实施e-business on demand用户的情况。现在,IBM正在转换成一个on de-mand的企业,自身希望利用on demand商业方法,在产品的研发、定单处理、生产等各个流程方面,使管理更有效。Wladawsky-Berger认为要真正成为一个on demand的电子商务企业,必须具备非常快的响应速度。     

分布式入侵检测模型研究

提出了分布级别的概念对分布式入侵检测系统进行分类，并引入信息抽象级别对入侵检测中审计数据所经历的逻辑抽象层次进行表述．在对现有的层次检测模型和协作检测模型的优点和缺陷进行详细分析之后，提出了一种用于分布式入侵检测系统的层次化协作模型(HCM)，并完成了相应的原型系统．该模型可以有效地综合两种现有模型的优点，在保证结点可控性和检测效率的同时提高系统的容错性和协作能力．     

基于CSCW的多媒体多模式集成模型的研究

ＣＳＣＷ是一个新的多学科领域．在分析ＣＳＣＷ的主要研究内容──多媒体多模式集成模型的主要研究内容和关键技术的基础上，提出了其协同工作空间模型、系统组成的功能模型和层次结构模型．     

A computation-oriented multimedia data streams model for content-based information retrieval

Multimedia applications nowadays are becoming prevalent. In the past the relational database model was generalized to the multimedia database model. More recently the relational database model was generalized to the data streams model, as the technology advanced and data became bulky and unbounded in size due to the utilization of sensor networks. In this paper we take one more step of generalization by providing a multimedia data streams model. The objective is to furnish a formal framework to design multimedia data streams (MMDS) schema for efficient content based information retrieval. We also extend the functional dependency theory and the normalization framework to handle multimedia data streams. Finally we present algorithmic methods of generating continuous multimedia queries along with examples for illustration.     

多媒体会议系统研究

多媒体会议系统是一种典型实用的计算机支持的协同工作（ＣＳＣＷ）应用，最近几年发展很快，受到了广泛的重视。我们从多媒体技术和计算机网络技术两方面出发对多媒体会议系统进行系统研究，在此基础上，提出多媒体会议系统的总体设计，特别是针对多媒体会议系统的关键问题和支持多媒体网络协议存在的问题，提出了多媒体通信服务模型，以试衅弥补当前网络协议对服务质量（ＱＯＳ）的不足，同时也给出了新服务模型下的参考实现框架。     

Heterogeneous and Multifaceted Multimedia Objects in DOOR/MM: A Role-Based Approach with Views

Although the distributed multimedia information system is getting popular nowadays, existing database systems do not offer adequate support to structural nor behavioral extension of multimedia objects. Moreover, the multifaceted nature of multimedia data has seldom been investigated. Besides the flexibility for multimedia authoring tools, dynamic extension and multifacet modeling can in general ease the task on integrating the multimedia information of heterogeneous formats over a distributed network. This paper presents the support of dynamic extension and multifacet modeling of multimedia objects in a client-server, object-role database system called DOOR. The resultant system, with multimedia functionalities, is named as DOOR/MM (DOOR with multimedia extensions). First, the underlying data model for DOOR is summarized. We then present the extension of the data model, by means of meta-object protocol (MOP), to implement the metaclasses for multimedia objects. In DOOR, objects are structured as a tree of roles. Each role may carry different properties and interact with other roles cooperatively. An object may acquire or drop multiple roles during its lifetime. Structural and behavioral extensions of multimedia objects are achieved by dynamic role playing. Multifaceted interfaces of an multimedia object are modeled by means of views on roles. In particular, we discuss different ways of using views to model different abstraction levels of the heterogeneous multimedia resources. Throughout the paper, examples such as text, bitmap, MIDI, and 3D graphic objects are used to demonstrate the significance of our approach.     

基于分布式环境的多媒体同步应用框架的设计

多媒体信息的同步是分布式多媒体信息系统的关键技术，在Meyer,Effelsberg等人的4层媒体同步参考模型的基础上，提出了一个实际应用的分布式多媒体同步应用框架，并对其中的一些关键内容及模块进行了讨论。     

On automated lesson construction from electronic textbooks

An electronic book may be viewed as an application with a multimedia database. We define an electronic textbook as an electronic book that is used in conjunction with instructional resources such as lectures. We propose an electronic textbook data model with topics, topic sources, metalinks (relationships among topics), and instructional modules, which are multimedia presentations possibly capturing real-life lectures of instructors. Using the data model, the system provides users a topic-guided multimedia lesson construction. We concentrate, in detail, on the use of one metalink type in lesson construction, namely, prerequisite dependencies, and provide a sound and complete axiomatization of prerequisite dependencies. We present a simple automated way of constructing lessons for users where the user lists a set of topic names (s)he is interested in, and the system automatically constructs and delivers the "best" user-tailored lesson as a multimedia presentation, where "best" is characterized in terms of both topic closures with respect to prerequisite dependencies and what the user knows about topics. We model and present sample lesson construction requests for users, discuss their complexity, and give algorithms that evaluate such requests. For expensive lesson construction requests, we list heuristics and empirically evaluate their performance. We also discuss the worst-case performance guarantees of lesson request algorithms.     

A model for specification and synchronization of data for distributed multimedia applications

As network technology provides the capability to handle multimedia traffic and the demand of multimedia services increases, protocols are required for effective communication of multimedia data in a distributed environment. Synchronization is one of the key issues in a multimedia system. Most of the current approaches do not support an integrated solution to the problem of synchronization. In this paper we propose a mechanism for synchronization of multimedia data in distributed environment where the accuracy of the protocol can be tailored to the application. The system model supports live and video-on-demand service. We present a scheme where the specification of the temporal requirements provided by the application can be directly mapped to obtain the information necessary to enforce the synchronization required. We present two examples of specifying the temporal requirements and process of obtaining the information and present performance results of our simulation studies.     

Interactive hypermedia applications: A model and its implementation

By referring to the object-oriented efforts of the Multimedia and Hypermedia information coding Expert Group (MHEG), and the augmented Petri net model, we present a formal definition of the multimedia hypermedia Petri net (MHPN) model. Through this proposed model, issues of authoring, rendering and synchronization of multimedia information (i.e. structure authoring, spatial temporal relationships, user interaction, etc.) can all be laid to rest. We have implemented a testbed system, the Petri net object information system (POIS), which offers considerable potential for the development of distributed hypermedia applications. The testbed has been implemented on an IBM-PC486 under Windows 3.1. We are now in the process of porting the testbed model to Windows NT.     

Modeling spatio-temporal constraints for multimedia objects

The presentation of multimedia data is not only characterized by precise temporal constraints; also spatial constraints must be taken into account. An important requirement in multimedia systems is thus the integrated modeling of spatio-temporal constraints. Moreover, it is important to devise methods for checking the consistency of the specified constraints. In this paper, we first propose a spatio-temporal object graph (STOG) model that provides an integrated and graphical representation of spatio-temporal constraints. Second, we investigate consistency conditions between spatial and temporal constraints expressed in the STOG model. Then, we present a prototype system implementing the proposed model.     

多媒体任务管理中的过程模型及其形式化描述

多媒体任务管理(称为MTM)是一个多媒体业务过程的全部或部分自动执行.为了实现多媒体任务管理,必须将多媒体业务过程从现实世界中抽象出来,并用一种形式化方法对其进行描述,其结果称为多媒体任务的过程模型.提出了一种面向图的多媒体任务过程模型(称为GOMM).GOMM由多媒体内容所涉及的不可分割的、自包含的媒体、语义、功能3方面特征及版本信息组成.提供了把本体知识集成进GOMM的方法,并对GOMM进行了形式化描述.