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1.
Multimedia presentations are the basic objects of multimedia databases. Since a multimedia presentation is not an instant display of a query result, the control knowledge (or synchronization requirements) has to be incorporated into the database and necessary precautions have to be taken for a lengthy presentation. Active databases provide a mechanism for incorporation of control knowledge by using event-condition-action (ECA) rules. In this paper, we describe how multimedia synchronization can be handled within a database using ECA rules. We present a prototype presentation synchronization database, named as PressBase, for distributed multimedia systems. We have adopted one of the synchronization models, SynchRuler, and then incorporated into a relational database system. 相似文献
2.
Increased network speeds coupled with new services delivered via the Internet have increased the demand for intelligence and
flexibility in network systems. This paper argues that both can be provided by new hardware platforms comprised of heterogeneous
multi-core systems with specialized communication support. We present and evaluate an experimental network service platform
that uses an emergent class of devices—network processors—as its communication support, coupled via a dedicated interconnect
to a host processor acting as a computational core. A software infrastructure spanning both enables the dynamic creation of
application-specific services on the network processor, mediated by middleware and controlled by kernel-level communication
support. Experimental evaluations use a Pentium IV-based computational core coupled with an IXP 2400 network processor. The
sample application services run on both include an image manipulation application and application-level multicasting.
相似文献
3.
The delivery of continuous and synchronous multimedia data from a database (or file) server to multiple destinations over
a network presents new challenges in the area of buffer management. Many factors that were not considered in conventional
buffer management must be examined. In this paper, we investigate the principles of buffer model and management for multimedia
data presentations in distributed systems. The primary goal is to minimize the response time of multimedia presentations while
ensuring that all continuity and synchronization requirements are satisfied. A framework for buffer model and management is
introduced. Minimum buffering requirements at both client and server sides to guarantee the continuity and synchrony of the
presentation of multimedia data are examined. A prefetching and replacement strategy which satisfies these requirements is
then offered. These principles and techniques provide users with the full range of information required to develop a distributed
system for multimedia presentations. 相似文献
4.
In this paper we present IMP, a platform to support the authoring and run-time management of interactive multimedia applications in distributed environments. The multi-level platform model encourages slot-in extensibility to cater for the evolving environment. We illustrate with our prototype platform built above the Cambridge multimedia environment. The authoring model emphasises reusability, tailorability and use of environment features in a uniform way. We have shown the validity of our approach by constructing a variety of application types. 相似文献
5.
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. 相似文献
6.
In a distributed environment, the presentation of structured, composite multimedia information poses new challenges in dealing
with variable bandwidth (BW) requirements and synchronization of media data objects. The detailed knowledge of BW requirements
obtained by analyzing document structure can be used for efficient utilization of system resources. A client–server environment
consists of various system components that are either dedicated to a client (e.g., client buffer space and BW) or shared across
multiple clients (e.g., server buffer space and BW). A shared server could benefit from fine granularity advanced reservation
of resources based on true BW requirements. Prefetching by utilizing advance knowledge of BW requirements can further improve
resource utilization. The prefetch schedule needs also to be aware of the BW fragmentation in a partitioned server. In this paper, we describe the JINSIL middleware for retrieval of a composite document that takes into account the available
BW and buffer resources and the nature of sharing in each component on delivery paths. It reshapes BW requirements, creates
prefetch schedules for efficient resource utilization in clients and servers, and reserves necessary BW and buffer space.
We also consider good choices for placement of prefetch buffers across client and server nodes. 相似文献
7.
In the face of massive parallel multimedia streaming and user access, multimedia servers are often in an overload state, resulting in the delay of service response and the low utilization of wireless resources, which makes it is difficult to satisfy the user experience quality. Aiming at the problems of low utilization rate of multimedia communication resources and large computing load of servers, this paper proposes a self management mechanism and architecture of wireless resources based on multimedia flow green communication. First, based on the combination of multimedia server, relay base station and user cluster, a multimedia green communication system architecture is built based on the comprehensive utilization rate of multimedia communication, and a cluster green communication control algorithm is proposed. Secondly, aiming at the dynamic service demand and asynchronous multimedia communication environment, aiming at ensuring the balance of resource allocation and accelerating the speed of resource allocation, we build a dynamic multimedia wireless resource architecture. Finally, the experimental results of statistics and analysis, from the server in different scale parallel multimedia streams under different scale delay, number of users relay network free resources proportion, user satisfaction, packet loss rate and other performance show that the proposed algorithm is effective and feasible. 相似文献
8.
We address the problem of integrating user preferences with network quality of service parameters for the streaming of media content, and suggest protocol stack configurations that satisfy user and technical requirements to the best available degree. Our approach is able to handle inconsistencies between user and networking considerations, formulating the problem of construction of tailor-made protocols as a prioritization problem, solvable using fuzzy programming. 相似文献
9.
This paper presents the Distributed InterProcess Communication System (DIPCS) as a framework for managing communication in a distributed multimedia system. Within DIPCS, connection level management is provided through a novel distributed process group model called ADP-Group communication. The ADP-Group paradigm defines a new type of group message passing, called qos-reliable. Qos-reliable semantics are appropriate to controlling real-time multimedia communication, by allowing a spectrum of performance and reliability specifications to co-exist within one group. DIPCS also provides an abstract programming model of multimedia devices, easing control of a heterogeneous multimedia system. Distributed multimedia applications can be rapidly developed using simple group operation primitives. We show how ADP-Group message delivery semantics can be directly mapped into an efficient Integrated Services Network support policy.Supported by Computational Diagnostics, Inc., and the Benjamin Franklin Fund for the Commonwealth of Pennsylvania.Supported by the Rome Laboratory (RL) of the Air Force Material Command and the Defense Advanced Research Projects Agency (Contract F30602-93-C-0038). 相似文献
11.
Multimedia systems must be able to support a certain quality of service (QoS) to satisfy the stringent real-time performance
requirements of their applications. HeiRAT, the Heidelberg Resource Administration Technique, is a comprehensive QoS management
system that was designed and implemented in connection with a distributed multimedia platform for networked PCs and workstations.
HeiRAT includes techniques for QoS negotiation, QoS calculation, resource reservation, and resource scheduling for local and
network resources. 相似文献
12.
To simplify the task of building distributed streaming applications, we propose a new abstraction for information flow –
Infopipes. Infopipes make information flow primary, not an auxiliary mechanism that is hidden away. Systems are built by connecting
predefined component Infopipes such as sources, sinks, buffers, filters, broadcasting pipes, and multiplexing pipes. The goal
of Infopipes is not to hide communication, like an RPC system, but to reify it: to represent communication explicitly as objects that the program can interrogate and manipulate. Moreover, these objects
represent communication in application-level terms, not in terms of network or process implementation. 相似文献
13.
The Journal of Supercomputing - In this study, we investigated the problem of scheduling streaming applications on a heterogeneous cluster environment and, based on our previous work, developed the... 相似文献
14.
SuiteSound, a programming environment with integrated support for multimedia, is discussed. SuiteSound is built in the Suite object-based system on a conventional UNIX operating system. SuiteSound objects incorporate multimedia by creating flows and filters. Flows are streams of multimedia data moving through a sequence of objects. They bridge the gap between objects representing the state of an entity at a discrete point in time and space and continuous media such as live audio or video. Filters are intermediate objects between the source and destination of a flow. They take flow as input, perform one of several operations such as multiplex-in, multiplex-out, gain control, or silence deletion on it, and send the resulting flow to its destination. In effect, they provide a virtual device interface for the application programmer that is uniform and independent of any physical device. The design and implementation of SuiteSound on the Sun SparcStation are described. Experiments performed to determine the network and CPU load of the sound tool are reviewed 相似文献
15.
In this paper, we present a separable, reusable middleware solution that provides coordinated, end-to-end QoS management
over any type of service component, and can use existing (legacy) QoS management solutions (by using wrappers) in a distributed
multimedia system. Our middleware solution incorporates strategic and tactical QoS managers, and supports protocols and messages
between tactical managers and managed application components, and between QoS managers in the management hierarchy. Strategic
QoS managers take a global view of QoS provided by a set of application components within the manager's policy domain. Tactical
QoS managers provide local control over application components. We introduce the concept of QoS policy domains to scope the
authority of a strategic QoS manager. We describe how the management hierarchy is dynamically configured and reconfigured
based on runtime needs of the application. 相似文献
16.
One of the challenges in the design of a distributed multimedia system
is devising suitable specification models for various schemas in
different levels of the system.
Another important research issue is
the integration and synchronization of heterogeneous multimedia
objects. In this paper, we present our models for multimedia schemas
and transformation algorithms. They transform high-level
multimedia objects into schemas that can be used to
support the presentation and communication of the multimedia objects.
A key module in the system is the Object Exchange Manager (OEM). In this paper,
we present the design and implementation of the OEM module,
and discuss in detail the interaction
between the OEM and other modules in a
distributed multimedia system. 相似文献
17.
The way by which multimedia contents are produced, delivered across networks, and consumed by intended users have shifted
significantly during the past 10 years. In this paper we postulate that, in the near future, flexible and self-organizing
facilities will play a dominating role in distributed multimedia systems. We discuss how such systems can be designed, using
a three-layer (sensor, distribution, and user layer) architecture, SOMA (Self Organizing Multimedia Architecture), as an example.
We also present innovative directions in three main aspects of self-organized multimedia systems: (i) the self-organizing
aspects of multimedia user communities, e.g., the wisdom, intentions, and needs of users; (ii) a fresh look at video streams
that treat them as a collection of units that can be composed taking user and network aspects into account; and (iii) new
delivery paradigms and how self-organization and multimedia delivery can be combined. 相似文献
18.
Object Composition Petri Nets, Priority Petri Nets, Dynamic OCPN, and Enhanced P-Nets have extended the original Petri Net to achieve the modeling of media synchronization and asynchronous user interactions during multimedia playback. The dynamic Petri Net (DPN) has been conceptualized to tackle existing problems in these two areas of modeling distributed multimedia systems. DPN features dynamic modeling elements which allows iteration and hence is able to reduce graph sizes of synchronous playback models while allowing greater details to be shown. DPN also introduces asynchronous event handling techniques that are powerful and effective. DPN was used in the design and modeling of a multimedia orchestration tool which is a typical representation of an application that works in a distributed multimedia system. 相似文献
19.
Multimedia Tools and Applications - Cloud computing is a new technology that is increasing in popularity day-by-day. One of the reasons for its popularity can be its elasticity feature. In other... 相似文献
20.
Without user interactions, multimedia presentations are just fancy slide shows with sound and video supports. User interactions
by themselves do not change the temporal relationships among multimedia objects, such as texts, graphics, images, audio, and
video, but affect the playback schedules. In this paper, we propose a synchronization mechanism to guarantee the quality of
multimedia presentation with user interactions. In our protocol, each presentation site requests media transmission from the
required media servers at certain time intervals prior to the playback deadlines, where these time intervals are the response
times to cover possible experienced end-to-end delays and packet losses, and waits for an initial setup time to ensure intermedia
synchronization before starting the presentation. Users may interact with the presentation. This synchronization mechanism
solves the problems incurred by user interactions by determining the new presentation scenario produced by the interactive
operation, calculating the corresponding setup time, and then rendering the new playback and retrieval schedules. 相似文献
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