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QoS Parameters (qo + parameter)

Distribution by Scientific Domains
Engineering60%

Selected Abstracts

A quality-of-service-based framework for creating distributed heterogeneous software components

CONCURRENCY AND COMPUTATION: PRACTICE & EXPERIENCE, Issue 12 2002
Rajeev R. Raje
Abstract Component-based software development offers a promising solution for taming the complexity found in today's distributed applications. Today's and future distributed software systems will certainly require combining heterogeneous software components that are geographically dispersed. For the successful deployment of such a software system, it is necessary that its realization, based on assembling heterogeneous components, not only meets the functional requirements, but also satisfies the non-functional criteria such as the desired quality of service (QoS). In this paper, a framework based on the notions of a meta-component model, a generative domain model and QoS parameters is described. A formal specification based on two-level grammar is used to represent these notions in a tightly integrated way so that QoS becomes a part of the generative domain model. A simple case study is described in the context of this framework. Copyright © 2002 John Wiley & Sons, Ltd. [source]

An adaptive min,max fair bandwidth allocation scheme for cellular multimedia networks

EUROPEAN TRANSACTIONS ON TELECOMMUNICATIONS, Issue 5 2006
Mohammad Mahfuzul Islam
Depending on the flexibility in controlling the transmission rate and the differences between on-line (real time) and off-line transmission modes, multimedia applications can potentially include a wide range of services, with the traditional stringent quality-of-service (QoS) requirement at the extreme to the highly adaptive ones that can tolerate or smartly adapt to the transient fluctuations in the QoS parameters. Keeping the cellular multimedia networks efficient with low call dropping and blocking rates and high bandwidth utilisation while maintaining a fair distribution of bandwidth by synergistically addressing the differences among these services remains a significant challenge. This paper addresses this issue by developing a novel min,max fairness scheme where bandwidth is distributed with equal share only after ensuring the minimum requirements. Besides borrowing in-use bandwidth through redistribution, this scheme also allows for using the reserved bandwidth for the offline services. Simulation results confirm the superiority of this scheme against the rate-based borrowing and the max,min fairness schemes, the two most recent works addressing similar issues. Copyright © 2005 AEIT. [source]

The end-user application toolkit: a QoS portal for the next generation Internet

INTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS, Issue 7 2003
Charilaos A. Tsetsekas
Abstract The support of quality of service (QoS) in the Internet has become one of the most important topics within the Internet community. The introduction of the Integrated Services (IntServ) and the Differentiated Services (DiffServ) architectures was a major breakthrough in this direction. Enhanced by the Bandwidth Broker concept, DiffServ aims to provide QoS in the Internet through the prioritization of some IP flows over others. However, up to now the DiffServ architecture lacks a standard mechanism for the interaction between users/applications and the Bandwidth Brokers (BB), so that end-to-end QoS can be achieved. In this paper we present a distributed middleware architecture for the transparent support of QoS in the Internet. The paper focuses on bridging the gap that currently exists between applications and the network and presents the end-user application toolkit (EAT). The EAT middleware provides a framework for the presentation of network services to users, the description and selection of QoS parameters, the forwarding of reservation requests and the verification of the accredited QoS level. Through the concept of application profiles, it aims to support QoS for legacy applications, that is, commercial applications that cannot be modified to support QoS. Copyright © 2003 John Wiley & Sons, Ltd. [source]

Quality of service for satellite IP networks: a survey

INTERNATIONAL JOURNAL OF SATELLITE COMMUNICATIONS AND NETWORKING, Issue 4-5 2003
Sastri Kota
Abstract The future media rich applications such as media streaming, content delivery distribution and broadband access require a network infrastructure that offers greater bandwidth and service level guarantees. As the demand for new applications increases, ,best effort' service is inadequate and results in lack of user satisfaction. End-to-end quality of service (QoS) requires the functional co-operation of all network layers. To meet future application requirements, satellite is an excellent candidate due to features such as global coverage, bandwidth flexibility, broadcast, multicast and reliability. At each layer, the user performance requirements should be achieved by implementation of efficient bandwidth allocation algorithms and satellite link impairment mitigation techniques. In this paper, a QoS framework for satellite IP networks including requirements, objectives and mechanisms are described. To fully understand end-to-end QoS at each layer, QoS parameters and the current research are surveyed. For example at physical layer (modulation, adaptive coding), link layer (bandwidth allocation), network layer (IntServ/DiffServ, MPLS traffic engineering), transport layer (TCP enhancements, and alternative transport protocols) and security issues are discussed. Some planned system examples, QoS simulations and experimental results are provided. The paper also includes the current status of the standardization of satellite IP by ETSI, ITU and IETF organizations. Copyright © 2003 John Wiley & Sons, Ltd. [source]

The impact of cognitive styles on perceptual distributed multimedia quality

BRITISH JOURNAL OF EDUCATIONAL TECHNOLOGY, Issue 4 2003
Gheorghita Ghinea
Multimedia technology has been widely used in web-based instruction, but previous studies have indicated that individual differences, especially cognitive styles, have significant effects on users' preferences with respect to presentation of multimedia content. However, such research has thus far neglected to examine the effect of cognitive styles on users' subjective perceptions of multimedia quality. This study aims to examine the relationships among users' cognitive styles, the multimedia Quality of Service (QoS) delivered by the underlying network, and Quality of Perception (QoP), which encompasses user levels of enjoyment and understanding of the informational content provided by multimedia material. Accordingly, 132 users took part in an experiment in which they were shown multimedia video clips presented with different values of two QoS parameters (frame rate and colour depth). Results show that, whilst the two QoS parameters do not impact user QoP, multimedia content and dynamism levels significantly influence the user understanding and enjoyment component of QoP. [source]