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Multimedia Applications (multimedia + application)
Selected AbstractsDesign and use of a multimedia trainer for the subject Descriptive GeometryCOMPUTER APPLICATIONS IN ENGINEERING EDUCATION, Issue 1 2009Máximo Pérez Morales Abstract Less and less time is being dedicated to Descriptive Geometry in Technical Careers. For that reason, a multimedia application that allows us improve and optimize the teaching,learning process in the resolution of typical problems of this subject has been designed. Easy of use, interactiveness or efficiency are characteristics that can be related to this application. In this article, we describe the more important aspects of the developed Multimedia Trainer, as well as the results obtained in an experience with students with the purpose of evaluating its possibilities of use. © 2008 Wiley Periodicals, Inc. Comput Appl Eng Educ 17: 13,24, 2009; Published online in Wiley InterScience (www.interscience.wiley.com); DOI 10.1002/cae20164 [source] A study on video performance of multipoint-to-point video streaming with multiple description coding over ad hoc networksELECTRICAL ENGINEERING IN JAPAN, Issue 4 2010Keisuke Utsu Abstract Supporting multimedia applications over wireless networks has become a very active research topic recently because video applications are forecast to receive high demand in future wireless networks, such as ad hoc networks. However, enabling video transmission over wireless ad hoc networks is more challenging than over other wireless networks due to node mobility, interference, and the absence of a supporting infrastructure. This paper addresses the problem of video transmission over ad hoc networks. We propose to combine Multiple Description Coding (MDC) with multiple source transport (Multipoint-to-Point transfer: MP2P) in order to maintain smooth video streaming over wireless ad hoc networks. In this paper, we describe a comprehensive simulation and test bed experiment designed to show the effect of the proposed MP2P video transfer with MDC for two description cases of video streaming over wireless ad hoc networks. The results show that the proposed mechanism successfully improves video transfer performance in terms of video packet reachability and throughput. © 2009 Wiley Periodicals, Inc. Electr Eng Jpn, 170(4): 43,50, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20999 [source] An adaptive min,max fair bandwidth allocation scheme for cellular multimedia networksEUROPEAN TRANSACTIONS ON TELECOMMUNICATIONS, Issue 5 2006Mohammad 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] Secure fast WLAN handoff using time-bound delegated authenticationINTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS, Issue 5 2009Hung-Yu Chien Abstract To support multimedia applications with good quality of services for roaming wireless local area network users, it is imperative to reduce the long re-authentication latency that users experience during handoff among access points (APs). Athough a great deal of research resources have been put into the reduction of the re-authentication latency, these schemes developed so far seem to either suffer from heavy overhead problems or have weak security. In this paper, we propose a novel approach to reducing the re-authentication latency. With the authentication server (AS) periodically delegating its authentication authority to the authenticated APs, the APs can authenticate the roaming users on behalf of the AS. As our performance analysis and simulation results demonstrate, our new approach is capable of greatly reducing the latency and overhead while achieving a high security level. Furthermore, it does not increase the complexity on the AP side because only the already existing four-way handshake with new keying mechanism is required. Copyright © 2008 John Wiley & Sons, Ltd. [source] Characterizing user-perceived impairment events using end-to-end measurementsINTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS, Issue 10 2005Soshant Bali Abstract Measures of quality of service (QoS) must correlate to end-user experience. For multimedia services, these metrics should focus on the phenomena that are observable by the end-user. Metrics such as delay and loss may have little direct meaning to the end-user because knowledge of specific coding and/or adaptive techniques is required to translate delay and loss to the user-perceived performance. Impairment events, as defined in this paper, are observable by the end-users independent of coding, adaptive playout or packet loss concealment techniques employed by their multimedia applications. Time between impairments and duration of impairments are metrics that are easily understandable by a network user. Methods to detect these impairment events using end-to-end measurements are developed here. In addition, techniques to identify Layer 2 route changes and congestion events using end-to-end measurements are also developed. These are useful in determining what caused the impairments. End-to-end measurements were conducted for about 26 days on 9 different node pairs to evaluate the developed techniques. Impairments occurred at a high rate on the two paths on which congestion events were detected. On these two paths, congestion occurred for 6,8 hours during the day on weekdays. Impairments caused by route changes were rare but lasted for several minutes. Copyright © 2005 John Wiley & Sons, Ltd. [source] A new delay-constrained algorithm for multicast routing tree constructionINTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS, Issue 10 2004Mohamed Aissa Abstract New multimedia applications provide guaranteed end-to-end quality of service (QoS) and have stringent constraints on delay, delay-jitter, bandwidth, cost, etc. The main task of QoS routing is to find a route in the network, with sufficient resources to satisfy the constraints. Most multicast routing algorithms are not fast enough for large-scale networks and where the source node uses global cost information to construct a multicast tree. We propose a fast and simple heuristic algorithm (EPDT) for delay-constrained routing problem for multicast tree construction. This algorithm uses a greedy strategy based on shortest-path and minimal spanning trees. It combines the minimum cost and the minimum radius objectives by combining respectively optimal Prim's and Dijkstra's algorithms. It biases routes through destinations. Besides, it uses cost information only from neighbouring nodes as it proceeds, which makes it more practical, from an implementation point of view. Copyright © 2004 John Wiley & Sons, Ltd. [source] Congestion control for multimedia applications in the wireless internetINTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS, Issue 7 2004Veselin Rakocevic Abstract This paper provides a parallel review of two important issues for the next-generation multimedia networking. Firstly, the emerging multimedia applications require a fresh approach to congestion control in the Internet. Currently, congestion control is performed by TCP; it is optimised for data traffic flows, which are inherently elastic. Audio and video traffic do not find the sudden rate fluctuations imposed by the TCP multiplicative-decrease control algorithm optimal. The second important issue is the mobility support for multimedia applications. Wireless networks are characterized by a substantial packet loss due to the imperfection of the radio medium. This increased packet loss disturbs the foundation of TCP's loss-based congestion control. This paper contributes to the ongoing discussion about the Internet congestion control by providing a parallel analysis of these two issues. The paper describes the main challenges, design guidelines, and existing proposals for the Internet congestion control, optimised for the multimedia traffic in the wireless network environment. Copyright © 2004 John Wiley & Sons, Ltd. [source] Implementation solutions for the interworking between MMS and streamingINTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS, Issue 10 2003Miraj-E-Mostafa Abstract Multimedia messaging service (MMS) and streaming are forerunner multimedia applications in mobile communication. Use of streaming in the retrieval of continuous multimedia content of MMS is the identified optimum scope (extent) of interworking between MMS and streaming. The optimum interworking can remove a limitation visible in MMS,retrieving content requiring more storage space than available in a mobile terminal. This paper presents two different solutions for implementing the interworking. The implementation solutions are consistent with the existing mobile frameworks and the working principles and procedures of both MMS and streaming. Consistency is very important here not only to avoid creating isolated solution, but also to preserve user experience. This paper describes in detail how each of the solutions operates, including the process of using streaming in the MMS retrieval. Pros and cons of both the solutions are also analysed to compare those. Other important factors tackled in the analysis are implementation flexibility, complexity, terminal capability indication, and content adaptation. Copyright © 2003 John Wiley & Sons, Ltd. [source] Evaluating the expedited forwarding of voice traffic in a differentiated services networkINTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS, Issue 9 2002Artur Ziviani Abstract The Differentiated Services architecture offers a scalable alternative to provide Quality of Service (QoS) to the new multimedia applications in the Internet. This paper aims at evaluating the delay and jitter experienced by voice traffic when handled by the Expedited Forwarding (EF) scheme. The analysis includes the effects of different packet scheduling mechanisms implementing EF and of the voice packet size. We also evaluate how efficiently each type of traffic uses an extra allocated bandwidth and the impact of traffic shaping. The results show that increasing the service rate share allocated to the EF aggregate does not significantly affect the competing best effort (BE) traffic. This holds as long as the BE traffic can use the bandwidth left unused by the EF traffic in idle periods. Copyright © 2002 John Wiley & Sons, Ltd. [source] Efficient packet scheduling for heterogeneous multimedia provisioning over broadband satellite networks: An adaptive multidimensional QoS-based designINTERNATIONAL JOURNAL OF SATELLITE COMMUNICATIONS AND NETWORKING, Issue 1 2009Hongfei Du Abstract With their inherent broadcast capabilities and reliable extensive geographical coverage, the broadband satellite networks are emerging as a promising approach for the delivery of multimedia services in 3G and beyond systems. Given the limited capacity of the satellite component, to meet the diverse quality of service (QoS) demands of multimedia applications, it is highly desired that the available resources can be adaptively utilized in an optimized way. In this paper, we draw our attention on the development and evaluation of an efficient packet scheduling scheme in a representative broadband satellite system, namely satellite digital multimedia broadcasting (SDMB), which is positioned as one of the most attractive solutions in the convergence of a closer integration with the terrestrial mobile networks for a cost-effective delivery of point-to-multipoint services. By taking into account essential aspects of a successful QoS provisioning while preserving the system power/resource constraints, the proposed adaptive multidimensional QoS-based (AMQ) packet scheduling scheme in this paper aims to effectively satisfy diverse QoS requirements and adaptively optimize the resource utilization for the satellite multimedia broadcasting. The proposed scheme is formulated via an adaptive service prioritization algorithm and an adaptive resource allocation algorithm. By taking into account essential performance criteria, the former is capable of prioritizing contending flows based on the QoS preferences and performance dynamics, while the latter allocates the resources, in an adaptive manner, according to the current QoS satisfaction degree of each session. Simulation results show that the AMQ scheme achieves significantly better performance than those of existing schemes on multiple performance metrics, e.g. delay, throughput, channel utilization and fairness. Copyright © 2008 John Wiley & Sons, Ltd. [source] A bicriterion approach for routing problems in multimedia networksNETWORKS: AN INTERNATIONAL JOURNAL, Issue 4 2003João C. N. Clímaco Abstract Routing problems in communication networks supporting multiple services, namely, multimedia applications, involve the selection of paths satisfying multiple constraints (of a technical nature) and seeking simultaneously to "optimize" the associated metrics. Although traditional models in this area are single-objective, in many situations, it is important to consider different, eventually conflicting, objectives. In this paper, we consider a bicriterion model dedicated to calculating nondominated paths for specific traffic flows (associated with video services) in multiservice high-speed networks. The mathematical formulation of the problem and the bicriterion algorithmic approach developed for its resolution are presented together with computational tests regarding an application to video-traffic routing in a high-speed network. The algorithmic approach is an adaptation of recent work by Ernesto Martins and his collaborators, namely, the MPS algorithm. © 2003 Wiley Periodicals, Inc. [source] An analysis of capital expenses and performance trade-offs among IMS CSCF deployment optionsBELL LABS TECHNICAL JOURNAL, Issue 4 2008Anne Lee Service providers around the world are deploying or planning to deploy the IP Multimedia Subsystem (IMS) in their core networks. IMS allows the delivery of new multimedia applications that can enhance the user's experience and bring in new revenue for the operators. These operators are now faced with deciding how to best deploy the various IMS functional elements in their networks. In this paper, the authors provide a survey of the various options available to the operators and present an analysis of some of those deployment options. In particular, the paper addresses questions around the advantages and disadvantages of centralizing or distributing control functions such as the call session control function (CSCF) in terms of capital expenditure (CAPEX) costs and latency trade-offs. Without the proper deployment strategy, there can be major differences in the overall cost of the network and therefore it is important to perform such an analysis. Initial recommendations and general observations are given that can assist network planners and operators to more efficiently develop an IMS deployment strategy. Further analysis and study that includes operational expenditure (OPEX) costs should also be factored into the final decision. © 2008 Alcatel-Lucent. [source] End-to-end availability considerations for services over IMSBELL LABS TECHNICAL JOURNAL, Issue 3 2006Abhaya Asthana Lucent IP Multimedia Subsystem (IMS) architecture provides an open framework for multimedia applications that support blended text, voice, and video services. Providing objectives for service downtime and failure rates, which reflect the end customer perspective, can be used to drive corrective and preventive action that better satisfy end customer expectations. However, the frameworks and techniques to do this on an end-to-end basis for network solutions of the complexity and size of IMS are not well established. In this paper we address the questions of specifying, estimating, and verifying the end-to-end availability for services over IMS. The purpose of this paper is to present a framework for establishing availability requirements and service failure rate metrics, and for performing "end-to-end" service downtime analysis. The framework can be used to guide network design and evaluate end-to-end performance in the field. © 2006 Lucent Technologies Inc. [source] Service control for next-generation applications in wireless IP multimedia networksBELL LABS TECHNICAL JOURNAL, Issue 1 2003Lynell E. Cannell Within the 3rd Generation Partnership Project (3GPP), the thrust of the session initiation protocol (SIP)-based Internet protocol (IP) multimedia subsystem (IMS) is envisaged to allow a swift progression towards the provision of multimedia applications for increasingly demanding end users. The paradigm of service programmability using open network application programming interfaces (APIs), with open service access (OSA) as its main exponent, is helping to drive this development together with the use of SIP. The focal point of this paper will be the multimedia services architecture in the IMS by providing details of the interaction of the IMS and the application servers in the form of the OSA gateway and the SIP application server. The paper aims to assess the value of the IMS service control (ISC) interface on application server interaction in the IMS. The paper will provide an OSA application use case, and will also present the presence server as an example of a SIP application server that fits in with the IMS. © 2003 Lucent Technologies Inc. [source] | ||||||||||