Showing papers on "IP Multimedia Subsystem published in 1993"

Providing connection-oriented network services to mobile hosts

Abstract: Mobile computers using wireless networks, along with multimedia applications, are two emerging trends in computer systems. This new mobile multimedia computing environment presents many challenges, due to the requirements of multimedia applications and the mobile nature of hosts. We present several alternative schemes for maintaining network connections used to provide multimedia service, as hosts move through a nano-cellular radio network. These algorithms modify existing connections by partially reestablishing them to perform handoffs. Using a simple analytical model, we compare the schemes on the basis of the service disruption caused by handoffs, required buffering, and excess resources required to perform the handoffs.

Feedback Techniques for Intra-Media Continuity and Inter-Media Synchronization in Distributed Multimedia Systems

Abstract: Future advances in networking and storage will make it feasible to build multimedia on-demand servers that provide services similar to those of a neighbourhood videotape rental store over metropolitan area networks such as B-ISDN. Such multimedia servers can support real-time retrieval of multimedia objects by users onto their ISDN videophones and audiophones for playback. The design of techniques and protocols for providing continuous and synchronous access to multimedia services constitutes the subject matter of this paper

A synchronization and communication model for distributed multimedia objects

Abstract: As the demand for multimedia information systems increases and network technology provides the capability to handle multimedia data, effective communication and synchronization mechanisms are needed in a distributed environment to realize the successful retrieval, composition and presentation of multimedia objects. In this paper, we propose a specification model for the communication and synchronization of multimedia objects in a distributed environment. This model specifies all the necessary functions for the communication and presentation of multimedia objects. We also implement several synchronization schemes in our model that provide mechanisms to handle synchronization anomalies during the presentation of multimedia objects.

Efficient group communication with guaranteed quality of service

Abstract: A specific class of multimedia applications is expected to be of importance for future communication networks: multi-party interactive multimedia (MIM). Based on the isolation and characterization of MIM applications, concrete network support requirements are derived. The varying degree of connectivity, the vastly different sizes in terms of participants and the reliance on a guaranteed quality of service make MIM support a difficult problem. Starting with the definition of multimedia communication abstractions, principles of solutions are sketched. For an important subclass of applications, a particularly efficient and practicable alternative implementation based on half-duplex channels is introduced. Interfaces at both the transport and network layers are also considered. >

Multimedia user interfaces for telecommunications products and services

Abstract: The emergence of multimedia systems, which incorporate media types such as text, graphics, audio, video, and animation, has great potential to change how people interact with systems and with each other. As multimedia technologies and their applications in telecommunications products and services evolve, some critical human factors challenges in designing these systems are emerging. This paper describes how the use of new multimedia technologies, complemented by the proper application of human factors design principles, can enhance the usability of AT&T products and services. Examples of three types of applications — multimedia-based training, multimedia-based performance support, and multimedia conferencing — highlight challenges specific to the design of multimedia user interfaces.

Context-sensitive multimedia

Abstract: The integration of multimedia into heterogeneous computer applications exposes the need for context-sensitive multimedia objects which can adapt to the fluctuating resources and needs of the application The typical model of a multimedia application is to give the application access to a library of static multimedia objects System management of the presentation is limited to synchronization We contend that multimedia objects should be dynamic and adaptable to their application environments At the very least, multimedia objects should be scalable in terms of resource usage, eg, the use of screen space, network bandwidth, and computational resources Multimedia objects should also be able to alter their modes of representation in response to the changing needs of the user Finally, multimedia objects should be capable of altering their content to fit the preferences of the user and the context of the presentation We present a multimedia distribution system called O, which enables the creation of dynamic multimedia objects for distribution over a network These objects are `self-aware,' in that they can be programmed with the behaviors necessary to respond to a changing presentation environment O is featured as the multimedia distribution tool in both a personalized information retrieval application and a mapping application© (1993) COPYRIGHT SPIE--The International Society for Optical Engineering Downloading of the abstract is permitted for personal use only

The multimedia information link control

Abstract: This paper describes the preliminary design of a multimedia information link control (MILC) that provides a framework for multimedia application development. Many of the multimedia systems, such as distributed multimedia database system and multimedia conferencing system, involve communication via the network. However, the existing transmission protocols do not preserve the characteristics of multimedia information, like real-time requirements and the preservation of temporal relation between data streams. All these features must be included in the next generation transport protocol in order to efficiently support multimedia communication. The design of MILC is not only to exploit the characteristics of multimedia information, but also to modularize information and processing rather than processing alone. The object-oriented approach has been applied to model MILC. >

Network and Operating System Support for Digital Audio and Video: Third International Workshop, la Jolla, California, U. S. A., November 1992, Proceedings

Abstract: Adaptive, best-effort delivery of digital audio and video across packet-switched networks.- The architecture of rattlesnake: A real-time multimedia network.- Beyond ST-II: Fulfilling the requirements of multimedia communication.- An approach to real-time scheduling - but is it really a problem for multimedia?.- Design and analysis of a grouped sweeping scheme for multimedia storage management.- Admission control algorithms for multimedia on-demand servers.- The design and implementation of a continuous media storage server.- Performance studies of digital video in a client/server environment.- Basic synchronisation concepts in multimedia systems.- Synchronization in Joint-Viewing environments.- Synchronization of multi-sourced multimedia data for heterogeneous target systems.- An intermedia skew control system for multimedia data presentation.- System support for efficient dynamically-configurable multi-party interactive multimedia applications.- Requirements for network delivery of stored interactive multimedia.- Multimedia processing model for a distributed multimedia I/O system.- Enhancing the Touring Machine API to support integrated digital transport.- Preliminary measurement of the RMTP/RTIP.- The multimedia multicast channel.- Analysis of a resequencer model for multicast over ATM networks.- An integrated platform and computational model for open distributed multimedia applications.- Scheduling multimedia documents using temporal constraints.- The stratification system a design environment for random access video.- On the design of multimedia interchange formats.- Bus bandwidth management in a high resolution video workstation.- Analysis of I/O subsystem design for multimedia workstations.- Tactus: Toolkit-level support for synchronized interactive multimedia.- An analytical model for real-time multimedia disk scheduling.- Real-time scheduling support in Ultrix-4.2 for multimedia communication.- Continuous media synchronization in distributed multimedia systems.- High speed networks and the digital TV studio.- The impact of scaling on a multimedia connection architecture.- An admission control algorithm for predictive real-time service (extended abstract).- MEGAPHONE: A multimedia application based on object-oriented communication.- System support for dynamic QOS control of continuous media communication.- NMFS: Network multimedia file system protocol.- A continuous media player.- Architecture of a multimedia information system for content-based retrieval.- Application construction and component design in an object-oriented multimedia framework.- Audio and video extensions to graphical user interface toolkits.- An introduction to HeiMAT: The Heidelberg multimedia application toolkit.

A Call Model for Distributed Multimedia Communications

Abstract: Most experiments in building multimedia communications systems to date have adopted application architectures which are intended for communication-specific applications such as teleconferencing, and support only particular kinds of communication channels and mechanisms. This paper describes an application architecture which gives developers of diverse applications, from word processor and spreadsheet programs to large distributed multi-user systems, a means to enable users to control real-time communications directly in the context of their work. It also provides unifonn application-level control of distributed multimedia resources. It is designed for eventual use in a distributed object system and provides a programming interface based on intuitive operations on a telephone call which model basic communication tasks such as placing and forwarding a call. Analogies are drawn between properties of a call system and those of a window system. The architecture and its implementation allow numerous communication services to be controlled together and can control any service with a suitable switching interface. In addition to supporting switching for traditional communications media, it is possible, for example, to control sets of connections between clients and servers in a distributed computing environment. A particularly powerful example is provided by the addition of switching control for connections between X Windows clients and servers, giving rise to shared rnultitMdia workspaces which provide a seamless integration between personal work contexts and communication contexts.

Access transport network system for multimedia communication services

Abstract: Access transport networks are proposed for multimedia communications services, especially five-layer network architecture for intelligent multimedia services. In the proposed architecture, it is very important to develop the distributed cooperative problem solving protocol wherein agents exchange their knowledge and negotiate with each other. The distributed cooperative interprocess communication mechanism is proposed. >