The perceptual and attentive impact of delay and jitter in multimedia delivery

In this paper we present the results of a study that examines the user’s perception—understood as both information assimilation and subjective satisfaction—of multimedia quality, when impacted by varying network-level parameters (delay and jitter). In addition, we integrate eye-tracking assessment to provide a more complete understanding of user perception of multimedia quality. Results show that delay and jitter significantly affect user satisfaction; variation in video eye path when either no single/obvious point of focus exists or when the point of attention changes dramatically. Lastly, results showed that content variation significantly affected user satisfaction, as well as user information assimilation

Computing infrastructure issues in distributed communications systems : a survey of operating system transport system architectures

The performance of distributed applications (such as file transfer, remote login, tele-conferencing, full-motion video, and scientific visualization) is influenced by several factors that interact in complex ways. In particular, application performance is significantly affected both by communication infrastructure factors and computing infrastructure factors. Several communication infrastructure factors include channel speed, bit-error rate, and congestion at intermediate switching nodes. Computing infrastructure factors include (among other things) both protocol processing activities (such as connection management, flow control, error detection, and retransmission) and general operating system factors (such as memory latency, CPU speed, interrupt and context switching overhead, process architecture, and message buffering). Due to a several orders of magnitude increase in network channel speed and an increase in application diversity, performance bottlenecks are shifting from the network factors to the transport system factors.This paper defines an abstraction called an "Operating System Transport System Architecture" (OSTSA) that is used to classify the major components and services in the computing infrastructure. End-to-end network protocols such as TCP, TP4, VMTP, XTP, and Delta-t typically run on general-purpose computers, where they utilize various operating system resources such as processors, virtual memory, and network controllers. The OSTSA provides services that integrate these resources to support distributed applications running on local and wide area networks.A taxonomy is presented to evaluate OSTSAs in terms of their support for protocol processing activities. We use this taxonomy to compare and contrast five general-purpose commercial and experimental operating systems including System V UNIX, BSD UNIX, the x-kernel, Choices, and Xinu

A QoS monitoring system in a heterogeneous multi-domain DVB-H platform

The MobileTV, IPTV, and DVB standards (DVB-H/T) have been defined to offer mobile users interactive multimedia services with quality of service (QoS) consistency analogous to TV services. However, the market has yet to provide effective and economical solutions for the real-time delivery of such services to the corresponding transmitters over multi-domain IP networks. The monitoring system proposed in this paper enables the QoS in the IP networks involved in the delivery of real-time multimedia content to the transmitters to be ascertained. The system utilizes the QoS parameters defined in MPEG-2 Transport Streams to detect problems occurring in the heterogeneous multi-domain IP networks. The ability to detect problems having an adverse effect on QoS allows appropriate control actions to be determined to recover the QoS across the composite IP network. The design and implementation of the proposed QoS-Monitoring system (QoS-MS) is presented, followed by analysis of experimental results that demonstrate the feasibility of the system

Multicriteria decision making for enhanced perception-based multimedia communication

This paper proposes an approach that integrates technical concerns with user perceptual considerations for intelligent decision making in the construction of tailor-made multimedia communication protocols. Thus, the proposed approach, based on multicriteria decision making (MDM), incorporates not only classical networking considerations, but, indeed, user preferences as well. Furthermore, in keeping with the task-dependent nature consistently identified in multimedia scenarios, the suggested communication protocols also take into account the type of multimedia application that they are transporting. Lastly, this approach also opens the possibility for such protocols to dynamically adapt based on a changing operating environment and user's preferences

Multicriteria decision making for enhanced perception-based multimedia communication

This paper proposes an approach that integrates technical concerns with user perceptual considerations for intelligent decision making in the construction of tailor-made multimedia communication protocols. Thus, the proposed approach, based on multicriteria decision making (MDM), incorporates not only classical networking considerations, but, indeed, user preferences as well. Furthermore, in keeping with the task-dependent nature consistently identified in multimedia scenarios, the suggested communication protocols also take into account the type of multimedia application that they are transporting. Lastly, this approach also opens the possibility for such protocols to dynamically adapt based on a changing operating environment and user’s preferences

Managing the Adaptive Processing of Distributed Multimedia Information

The term multimedia conjures up visions of desktop computers reproducing digital movies, high-resolution images and stereo sound. While many current systems support such functionality, none do so elegantly-especially when data is fetched and synchronized from dissimilar sources distributed across resource-limited networks. Our research investigates general approaches for managing the flow of multimedia information in a distributed computing environment, providing adaptive support for time-sensitive retrieval and presentation based on multimedia document specifications. The benefit of our approach is that it provides flexible, content-based utilization of resources without over

The Integrated Media Approach to Networked Multimedia Systems

Applications which require real-time multimedia services[13] face a number of difficult problems in the transmission of multimedia information. Among the most difficult problems are the heterogeneity of end nodes and the heterogeneity of media Quality of Service (QoS) requirements. End nodes typically consist of a computer and number of sensory input and output devices, such as displays, microphones, and cameras. QoS requirements[18] include degrees of reliability, jitter, and delay. We propose an integrated approach to address these problems. Multimedia input data comprise a sensory environment which an application will make available; these data are packaged together into an Integrated Multimedia Message (IMM). From a received IMM, output data are selectively reproduced to create another sensory environment. We propose an IMM format and protocol behaviors for generation, presentation, and synchronization of these messages. While IMM\u27s are aesthetically pleasing, well-suited to proposed high- speed networks, and ease intramessage synchronization, they are potentially plagued by the need to deliver QoS which meets the worst-case requirements of all of their components[6]. We believe that this problem can be addressed, and are testing that belief experimentally with the U. Penn Experimental Multimedia Conferencing System, which will be embedded in the AURORA Gigabit Testbed