网络环境下动态分布内容的自组织语义整合框架

随着网络和多媒体技术的发展,新型网络技术不断出现,并通过互联网络不断融合,使得网络更加泛在化、开放和动态化.目前,网络中动态分布的内容爆炸式增长与用户个性化需求之间的矛盾也日益突出.因此,基于开放的网络环境下海量的内容,如何提供个性化、智能的内容服务,已成为研究界和工业界共同关注的问题.基于开放、动态的网络环境,以个性化的语义整合服务为核心目标,将语义技术与网络通信机制相结合,提出了动态分布内容自组织语义整合的网络结构和关键技术的实现机制,包括关系路由模型、自组织语义整合技术框架和实现流程,以支持在网络环境下针对动态分布的内容构建个性化和智能的语义整合应用,并且为动态分布内容的语义整合系统提供工程设计方案和技术实现方法.     

MING-I: a distributed interactive multimedia document development mechanism

The next generation of interactive multimedia documents can contain both static media, e.g., text, graph, image, and continuous media, e.g., audio and video, and can provide user interactions in distributed environments. However, the temporal information of multimedia documents cannot be described using traditional document structures, e.g., Open Document Architecture (ODA) and Standard Generalized Mark-up Language (SGML); the continuous transmission of media units also raises some new synchronization problems, which have not been met before, for processing user interactions. Thus, developing a distributed interactive multimedia document system should resolve the issues of document model, presentation control architecture, and control scheme. In this paper, we (i) propose a new multimedia document model that contains the logical structure, the layout structure, and the temporal structure to formally describe multimedia documents, and (ii) point out main interaction-based synchronization problems, and propose a control architecture and a token-based control scheme to solve these interaction-based synchronization problems. Based on the proposed document model, control architecture, and control scheme, a distributed interactive multimedia document development mechanism, which is called MING-I, is developed on SUN workstations.     

X window based group collaborative editing system

Group collaborative editing is an activity by which people geographically dispersed can edit the same document simultaneously. It makes use of computers and network communication to provide an interactive and convenient environment, so people can save much of their time and cost. We have developed a group collaborative editing system which not only allows participants to jointly view and process multimedia documents but also provides real-time interactive conversation facilities to let users feel realistic and friendly. This paper describes the concepts of group collaboration and the mechanisms of our system. It also presents the interface design strategy and the synchronization control method.     

A model for secure multimedia document database system in a distributed environment

The Internet provides a universal platform for large-scale distribution of information and supports inter-organizational services, system integration, and collaboration. Use of multimedia documents for dissemination and sharing of massive amounts of information is becoming a common practice for Internet-based applications and enterprises. With the rapid proliferation of multimedia data management technologies over the Internet, there is growing concern about security and privacy of information. Composing multimedia documents in a distributed heterogeneous environment involves integrating media objects from multiple security domains that may employ different access control policies for media objects. In this paper, we present a security model for distributed document management system that allows creation, storage, indexing, and presentation of secure multimedia documents. The model is based on a time augmented Petri-net and provides a flexible, multilevel access control mechanism that allows clearance-based access to different levels of information in a document. In addition, the model provides detailed multimedia synchronization requirements including deterministic and non-deterministic temporal relations and incomplete timing information among media objects.     

A Java framework for Web-based multimedia and collaborativeapplications

MultiTel is a compositional framework for developing collaborative multimedia applications, and also designates a Web-based distributed platform that supports intercomponent communication. This article shows how compositional and coordination paradigms can be successfully applied to design cooperative Java applications with multimedia data exchange. The focus is on multimedia and network architectures, which define generic and specific components coordinated by connectors for resolving the resource management needs of collaborative applications. The MultiTel platform composes application components dynamically, providing mechanisms for building services with plug-and-play transport and multimedia resources     

A Scalable Toolkit for Designing Multimedia Authoring Environments

This paper introduces Kaomi, a scalable toolkit for designing authoring environments of multimedia documents. The underlying concept is to provide the designer of multimedia applications with a fast method to get an authoring system based on a set of synchronized views (the presentation view for displaying the document, the scenario view for showing the temporal organization of the document, ...) so that each view is the support of editing actions. Kaomi is flexible enough to support a variety of multimedia documents declarative formats. It is indeed a scalable toolkit since it provides facilities for extending and/or for modifying the resulting authoring environment. In addition, cross-platform portability is provided which allows operation in the heterogenous Internet environment. The use of Kaomi is mainly described through the design of two authoring environments: one for authoring a sub-set of the Smil standard of the W3C and the other one for Madeus, a constraint based multimedia language.     

网格环境下基于HLA的分布交互仿真动态交互研究

基于HLA开发的分布交互仿真缺乏灵活性，不支持动态资源分配。网格服务是开发基于网络的分布交互仿真的另一途径，但只应用网格服务开发分布交互仿真，开发者必须自己创建通信机制来协调仿真执行。本文提出了一个动态交互框架，将基于HLA的分布交互仿真建立在网格服务的基础之上，来克服两者所存在的问题并发挥各自的优点，实现仿真资源的动态分配、动态状态监控及任务动态迁移。文中详细地阐述了框架的构成、框架关键服务构建的设计和实现、各种网格服务的机制及服务接口，并给出实例进行验证。     

A user-centric network communication broker for multimedia collaborative computing

The development of collaborative multimedia applications today follows a vertical development approach, where each application is built on top of low-level network abstractions such as the socket interface. This stovepipe development process is a major inhibitor that drives up the cost of development and slows down the innovation pace of new generations of communication applications. In this paper, we propose a network communication broker (NCB) that provides a unified higher-level abstraction for the class of multimedia collaborative applications. We demonstrate how NCB encapsulates the complexity of network-level communication control and media delivery, and expedites the development of applications with various communication logics. We investigate the minimum necessary requirements for the NCB abstraction. We identify that the concept of user-level sessions involving multiple parties and multiple media, is critical to designing a reusable NCB to facilitate next-generation multimedia communications. Furthermore, the internal design of NCB decouples the user-level sessions from network-level sessions, so that the NCB framework can accommodate heterogeneous networks, and applications can be easily ported to new network environments. In addition, we demonstrate how the extensible and self-managing design of NCB supports dynamic adaptation in response to changes in network conditions and user requirements.     

A CORBA Based QOS Support for Distributed Multimedia Applications

Advance object oriented computing platform such as the Common Object Request Broker Architecture (CORBA) provides a conducive and standardized framework for the development of distributed applications. Most of the off-the-shelf CORBA are implemented over legacy network transports and distributed processing platforms such as TCP/IP and RPC. They are not suitable for real-time applications due to their high processing overheads, and lack of features and mechanisms in supporting quality of service both at the network level and at the end-host level. To overcome this limitation we have designed and implemented a CORBA-based Real Time Stream Service (RTSS) that allows real-time streams to be managed through the CORBA channel but by-passing the heavy CORBA protocol stacks. RTSS aims to achieve an integrated QOS framework that incorporates both host scheduling and end-to-end network-level QOS to better support the processing of distributed multimedia applications over ATM networks. For host scheduling, a novel scheme of frequency-based scheduling mechanism has been proposed to cope with dynamic CPU load condition. The scheme has been implemented for a stand-alone host and will be extended to the networked environment. At the network-level QOS, RTSS provides object-oriented application programming interfaces (APIs) which guarantee end-to-end QOS when operating directly over ATM adaptation layers. The benefits of RTSS for the development of real-time multimedia distributed applications are demonstrated through a number of experiments.     

Using UML Profiles for Documenting Web-Based Application Frameworks

The Web now offers an exceptional infrastructure for the development of distributed collaborative services and applications. However, most of the existing applications only make use of the Web access and visualization facilities, without exploiting its distributed-processing potential capabilities. Web technologies are currently more focused on the provision of semantics to data and the design of dynamic Web pages, while paying little attention to the distributed architecture of the applications – that should go beyond client-server architectures. Application frameworks are one of the key technologies that may provide the mechanisms required for the design and development of reusable and scalable systems in these environments. However, the way to document such frameworks so they can be effectively tailored and reused still remains unresolved. In this paper we propose the use of UML profiles for documenting Web-based application frameworks, as a standard means for expressing their semantics. UML profiles allow all stakeholders of a system to share a common graphical notation and vocabulary, and permit more precise specifications and better documentation on how to use and customize applications. As an example, we build a UML profile for MultiTEL, a framework particularly well suited for the development of Internet-based multimedia and collaborative systems, and show how systems designers can use it to derive and document their applications.     

ViMediaNet: an emulation system for interactive multimedia based telepresence services

The telepresence service (TPS) leverages advanced communication, virtual reality, and cooperative web technologies to provide remote engaged users an immersive experience of being fully present, which are widely used in teleconferencing, remote surgery, and hazardous environment exploration. The common feature of TPS-based applications lies in that the users’ experiences heavily depend on the quality of interactive multimedia services, that is, most deliveries of multimedia contents are mission-critical, as well as time-critical, to ensure the control and operation accuracy for telerobots. Therefore, the delivery performance of multimedia contents over heterogeneous networks becomes the primary concern in the TPS system design, especially for those delay sensitive applications, like remote surgery and environment exploration. In this paper, we incorporate video processing tools with the network simulator to design and implement a joint emulation system, named as the virtual media network (ViMediaNet), through which, the TPS designer can readily deploy the TPS system over a heterogeneous network virtualized by the network emulator, investigate the critical network performance metrics in the multimedia content delivery, such as transmission delay and packet jitter, and observe control results in real time. To verify the capability of ViMediaNet in emulating the real-setting TPS system, we take a mobile device based vision navigation system as an example to evaluate performance impacts of the rate adaptation technology in the telerobot control. The experimental results reveal that the adaptive video streaming is a promising solution to significantly enhance the control accuracy of telerobots in TPS systems.     

基于CORBA的分布式多媒体服务的QoS模型

对于分布式多媒体来说,必须保证包括端系统、通讯系统以及网络在内的整个系统的服务质量（QoS）。CORBA提供了一个开放式的分布式对象计算环境,它能使许多普通的网络程序设计自动化,并允许应用在异构环境下无缝链接。文章根据分布式多媒体通讯系统中的层次结构模型（QOS－A）,提出了一种基于CORBA的分布式多媒体模型。     

Dynamic IP configuration of terminals in broadcasting networks

The concept of synergy between broadcasting and telecommunication networks has been strengthened by the emergence of multi-modal terminals, which are used in a broadcast environment (mainly in DTV-Digital Television networks) to provide IP-based multimedia services. The migration of IPv4/IPv6 applications, either interactive or not, in a broadcasting network, requires that certain parameters, such as Host, Gateway and DNS IP addresses are configured in the terminals, either statically or dynamically. This paper discusses issues of dynamic configuration of IP parameters for DTV terminals, based on an overview of relevant mechanisms usually used in access networks. It proposes an IP-based auto-configuration protocol tailored to the needs of an IP/DTV access platform, describes its implementation and evaluates its behaviour in a laboratory-based DVB-T network.     

MobiPADS: a reflective middleware for context-aware mobile computing

Traditionally, middleware technologies, such as CORBA, Java RMI, and Microsoft's DCOM, have provided a set of distributed computing services that essentially abstract the underlying network services to a monolithic "black box." In a mobile operating environment, the fundamental assumption of middleware abstracting a unified distributed service for all types of applications operating over a static network infrastructure is no longer valid. In particular, mobile applications are not able to leverage the benefits of adaptive computing to optimize its computation based on current contextual situations. In this paper, we introduce the Mobile Platform for Actively Deployable Service (MobiPADS) system. MobiPADS is designed to support context-aware processing by providing an executing platform to enable active service deployment and reconfiguration of the service composition in response to environments of varying contexts. Unlike most mobile middleware, MobiPADS supports dynamic adaptation at both the middleware and application layers to provide flexible configuration of resources to optimize the operations of mobile applications. Within the MobiPADS system, services (known as mobilets) are configured as chained service objects to provide augmented services to the underlying mobile applications so as to alleviate the adverse conditions of a wireless environment.     

协同多媒体菱工具中演示文档的同步模型

多媒体演示文档的协同菱对文档本身的结构与同步模型提出了一定的要求。为了便于面向对象的实现以及灵活多粒度的共享，提出了一个协同多媒体著作工具中分布交互式多媒体文档的同步模型。在此模型中，文档结构分为三层：页面层、对象组层及单媒体对象层，根据各层的特点，其同步分别采用基于跳转、基于事件及基于时间的策略。     

Collaborative clustering of XML documents

Clustering XML documents is extensively used to organize large collections of XML documents in groups that are coherent according to structure and/or content features. The growing availability of distributed XML sources and the variety of high-demand environments raise the need for clustering approaches that can exploit distributed processing techniques. Nevertheless, existing methods for clustering XML documents are designed to work in a centralized way. In this paper, we address the problem of clustering XML documents in a collaborative distributed framework. XML documents are first decomposed based on semantically cohesive subtrees, then modeled as transactional data that embed both XML structure and content information. The proposed clustering framework employs a centroid-based partitional clustering method that has been developed for a peer-to-peer network. Each peer in the network is allowed to compute a local clustering solution over its own data, and to exchange its cluster representatives with other peers. The exchanged representatives are used to compute representatives for the global clustering solution in a collaborative way. We evaluated effectiveness and efficiency of our approach on real XML document collections varying the number of peers. Results have shown that major advantages with respect to the corresponding centralized clustering setting are obtained in terms of runtime behavior, although clustering solutions can still be accurate with a moderately low number of nodes in the network. Moreover, the collaborativeness characteristic of our approach has revealed to be a convenient feature in distributed clustering as found in a comparative evaluation with a distributed non-collaborative clustering method.     

The Weka4WS framework for distributed data mining in service‐oriented Grids

The service‐oriented architecture paradigm can be exploited for the implementation of data and knowledge‐based applications in distributed environments. The Web services resource framework (WSRF) has recently emerged as the standard for the implementation of Grid services and applications. WSRF can be exploited for developing high‐level services for distributed data mining applications. This paper describes Weka4WS, a framework that extends the widely used open source Weka toolkit to support distributed data mining on WSRF‐enabled Grids. Weka4WS adopts the WSRF technology for running remote data mining algorithms and managing distributed computations. The Weka4WS user interface supports the execution of both local and remote data mining tasks. On every computing node, a WSRF‐compliant Web service is used to expose all the data mining algorithms provided by the Weka library. The paper describes the design and implementation of Weka4WS using the WSRF libraries and services provided by Globus Toolkit 4. A performance analysis of Weka4WS for executing distributed data mining tasks in different network scenarios is presented. Copyright © 2008 John Wiley & Sons, Ltd.     

A multimodal alignment framework for spoken documents

We present a multimodal document alignment framework, which highlights existing alignment relationships between documents that are discussed and recorded during multimedia events such as meetings. These relationships that should help indexing the archives of these events are detected using various techniques from natural language processing and information retrieval. The main alignment strategies studied are based on thematic, quotation and reference relationships. At the analysis level, the alignment framework was applied at several levels of granularity of documents, requiring specific document segmentation techniques. Our framework that is language independent was evaluated on corpora in French and English, including meetings and scientific presentations. The satisfactory evaluation results obtained at several stages show the importance of our approach in bridging the gap between meeting documents, independently from the language and domain. They highlight also the utility of the multimodal alignment in advanced applications, e.g. multimedia document browsing, content-based / temporal-based searching, etc.     

Multiuser 3D virtual simulation environments support in the Gnutella peer-to-peer network

One of the challenges for 3D multiuser virtual simulation environments (3DMUVEs) developers is to keep the shared virtual simulation environment synchronized among all the participating users’ terminals. Support to 3DMUVEs through traditional client–server communication model offers simpler management but can lead to bottlenecks and higher latencies. Peer-to-peer communication model, on the other hand, offers no central coordination but are more complex to manage. Current peer-to-peer networks, such as KaZaA and Gnutella, provide multimedia sharing services but do not support multiuser 3D virtual environment (VE) applications.This paper describes a solution to support 3DMUVEs in a hybrid peer-to-peer Gnutella network, which provides session control and distributed shared VE synchronization. As a result of this work, two components specified by the ongoing multiuser extension to the MPEG-4 standard were implemented and integrated to the Gnutella network for control and synchronization. This solution minimizes the disadvantages of client–server and pure peer-to-peer models. The results show that this approach can be a feasible solution, specially for spontaneous 3DMUVEs that can emerge from any user, with no investment needed (apart from his own computer). The use of peer-to-peer networks such as the Gnutella could be used as a test environment for companies wishing to check both their multiuser 3DMUVEs software for correctness and their acceptance by the users community before making heavy investments.     

MediaWeaver—A Distributed Media Authoring System for Networked Scholarly Workspaces

We describe MediaWeaver—a software framework for composing distributed media in the context of university research and instruction. Authors compose networked media, software tools and mediastreams, and can freely annotate media by media of any form using schema of their own design. Faculty and student authors compose distributed media using common Macintosh, World Wide Web and NeXTSTEP applications, supported by services from UNIX workstations.The MediaWeaver system mediates between network multimedia services and interface kits with which novice programmers and non-programmers may easily create radically different interactive views into shared mediabases. The network services include search engine abstractions, filters, relational modeling frameworks.MediaWeaver has supported collaborative projects in history, drama, music, art, anthropology, environmental studies, and other fields since 1993. Applications range from traditional relational text databases and indexed HTML WWW sites to course readers, research archives, journals and seminar spaces.