Pubs:conference

<bibtex> @inproceedings{ventresque2012a, address = {Dublin}, author = {Ventresque, Anthony and Bragard, Quentin and S. Liu, Elvis and Nowak,Dawid and Murphy, Murphy and Theodoropoulos, Georgios and Liu, Qi}, booktitle = {Distributed Simulations and Real-Time Applications (Ds-RT)}, title = {SParTSim: A Space Partitioning Guided by Road Network for Distributed Traffic Simulations}, year = {2012} } </bibtex> <bibtex> @inproceedings{Robitzsch2012a, address = {San Francisco}, author = {Robitzsch, Sebastian and Murphy, Liam}, booktitle = {World of Wireless Mobile and Multimedia Networks (WOWMOM Wkshps)}, title = {Analysis and Validation of the Maximal Reasonable Link Group Size in Static 802.11a Wireless Mesh Networks: A Study Towards Channel Assignment}, year = {2012}, pdf = {2012 - Robitzsch, Murphy - Analysis and Validation of the Maximal Reasonable Link Group Size in Static 802.11a Wireless Mesh Networks A Study Towards Channel Assignment.pdf} } </bibtex> <bibtex> @inproceedings{Robitzsch2012b, address = {San Francisco}, author = {Robitzsch, Sebastian and Murphy, Liam}, booktitle = {World of Wireless Mobile and Multimedia Networks (WOWMOM Wkshps)}, title = {Empirical Analysis of Measured 802.11 Receive Signal Strength Values Using Various Atheros Based Mini-PCI Cards}, year = {2012}, pdf= {2012 - Robitzsch, Murphy - Empirical Analysis of Measured 802.11 Receive Signal Strength Values Using Various Atheros Based Mini-PCI Cards.pdf} } </bibtex> <bibtex> @inproceedings{Robitzsch2011, abstract = {Self-Configuration Frameworks for 802.11 Wireless Mesh Networks mainly use measured Received Signal Strength values to mitigate interferences such as Adjacent Channel Interference and Inter Channel Interference by applying interference and capacity aware channel assignment algorithms and radio configuration techniques. For such tasks accurate Received Signal Strength values are essential with a granularity of less than 1 dB. This paper investigates the poor accuracy of Received Signal Strength values reported by Atheros chipsets and develops a Slope-Intercept approach to provide accurate Received Signal Strength values over various transmission power settings. In addition this work also investigates the mechanism by which ambient noise can enable the Ambient Noise Immunity feature implemented in Atheros chipsets and in the Linux Multiband Atheros Driver for Wireless Fidelity which negatively affects the reported Received Signal Strength and Noise Floor.}, author = {Robitzsch, Sebastian and Murphy, Liam and Fitzpatrick, John}, booktitle = {IEEE GLOBECOM Workshops (GC Wkshps)}, doi = {10.1109/GLOCOMW.2011.6162422}, pdf = {2011 - Robitzsch, Murphy, Fitzpatrick - An Analysis of the Received Signal Strength Accuracy in 802.11a Networks Using Atheros Chipsets A Solution Towards Self Configuration.pdf}, isbn = {978-1-4673-0040-7}, month = dec, pages = {1429--1434}, publisher = {IEEE}, title = {An Analysis of the Received Signal Strength Accuracy in 802.11a Networks Using Atheros Chipsets: A Solution Towards Self Configuration}, year = {2011} } </bibtex> <bibtex> @misc{Robitzsch2010a, address = {Athens}, author = {Robitzsch, Sebastian and Fitzpatrick, John and Murphy, Se\'{a}n and Murphy, Liam}, booktitle = {European Coorperation in the Field of Scientific and Technical Research, COST 2100}, publisher = {European Coorperation in the Field of Scientific and Technical Research, COST 2100}, title = {An Experimental Evaluation of Co-Channel Interference in IEEE802.11a Multi-Radio Mesh Nodes}, year = {2010}, pdf = {2010 - Robitzsch et al. - Behind-the-Scenes of IEEE 802.11a Based Multi-Radio Mesh Networks A Measurement Driven Evaluation of Inter-Channel Interference.pdf} } </bibtex> <bibtex> @inproceedings{254, author={Bogdan Ciubotaru; Gabriel–Miro Muntean}, title={Smooth Adaptive Soft Handover Algorithm for Multimedia Streaming over Wireless Networks}, booktitle={IEEE Wireless Communications & Networking Conference (WCNC)}, year={2009}, abstract={Inter-network mobility is achieved by allowing a mobile node to change its point of attachment to the network while preserving connectivity to its corresponding nodes. Most handover solutions proposed in the literature directly change the whole data flow from one network to another relying on only one network to transfer the entire data stream. These solutions involve a certain amount of quality degradation due to increasing loss and delay and suffer in terms of scalability, efficient resource allocation and resilience to different mobile node speeds. This paper proposes the Smooth Adaptive Soft-Handover Algorithm (SASHA) which increases the quality of the multimedia delivery process when performing handover in heterogeneous wireless environment by gracefully transferring the load from one connection to the other. }, keywords={Heterogeneous mobile networks, Handover, Load balance, Multimedia streaming}, pdf={Ciubotaru_Muntean_WCNC_09.pdf}, } </bibtex> <bibtex> @inproceedings{256, author={Vasile Horia Muntean and Gabriel-Miro Muntean}, title={A Novel Adaptive Multimedia Delivery Algorithm for Increasing User Quality of Experience during Wireless and Mobile E-learning}, booktitle={IEEE International Symposium on Broadband Multimedia Systems and Broadcasting (BMSB)}, year={2009}, abstract={Multimedia content is distributed via all types of networks to viewers found in a variety of locations and using different types of devices. Increasing the performance of multimedia stream delivery requires overcoming many technological challenges, all of them having a direct effect on the user perceived quality of experience. The quality of experience influences in turn the quality of any e-learning process. This is as users in general and learners in particular are becoming increasingly quality-aware in their expectations. Therefore delivering a good quality video stream as a part of any e-learning process is very important. This paper proposes a new adaptive multimedia delivery algorithm which can be used in the context of e-learning. The Dynamic Quality Oriented Adaptation Scheme (D-QOAS) adapts the multimedia content sent based on both user preferences and network conditions, while adjusting dynamically its adaptation policy during delivery. Simulation results show that for different user profiles and various network conditions the improvement in end-user perceived quality is significant. Important benefits are obtained in terms of the total number of simultaneous users and in the link utilization, as well as in quality as measured by some video quality metrics.}, keywords={dynamic content adaptation, e-learning, multimedia, rate control, wireless networks}, } </bibtex> <bibtex> @inproceedings{259, author={Brid Kilbane; Sabine Moebs; Jennifer McManis}, title={Learning Styles or Not? A Classroom Experience}, booktitle={EdTech 2009 - the Irish Educational Technology Users' Conference}, year={2009}, abstract={Secondary Teacher Assistant Researchers (STARs) is a program of Science Foundation Ireland (SFI) that supports research collaboration between secondary school teachers and SFI funded scientists and engineers. The main idea of the program is to disseminate new skills and knowledge to teachers, which can be passed on to their students, by providing them an opportunity to work in a research laboratory. The goal of the project “Social Media to Support Learning Styles of Secondary Students in the Junior Cycle” was to explore whether a blended learning setting consisting of online learning materials matching different learning styles in addition to a face-to-face class results in a significant impact on the learning results.}, keywords={learning styles, blended learning, social media}, pdf={poster_Kilbane_moebs_mcmanis_final_090501.pdf}, } </bibtex> <bibtex> @inproceedings{260, author={Andreea Molnar; Cristina Hava Muntean}, title={Enhancing Domain Model with Performance Oriented Metadata for Adaptive E-learning Systems }, booktitle={EdTech}, year={2009}, abstract={Due to the increasing complexity of web site navigation, but also as a response to the “one size fits all” approach, adaptation mechanisms have emerged and have started to be used by a large number of on-line educational systems. As educational content may be delivered though various types of networks that differ in characteristics and vary with the time, the quality of the transmitted information is affected. PAMAH (Performance-Aware Multimedia-based Adaptive Hypermedia) proposes to overcome this barrier by taking into consideration in the personalisation process not only the classic learner profile but also the performance of the network connection used by the learner, when rich media content is delivered. This paper focuses on presenting performance oriented metadata required for modelling the educational content and for enhancing the adaptation process. The goal is to provide a personalised media rich content suitable for the learner network connection. }, keywords={Adaptive and personalized e-learning, domain modelling, multimedia }, pdf={Enhancing Domain Model with Performance Oriented Metadata for Adaptive E-learning Systems.pdf}, } </bibtex> <bibtex> @inproceedings{261, author={Andreea Molnar; Cristina Hava Muntean}, title={Performance Aware and Cost Oriented Adaptive e-Learning Framework}, booktitle={IADIS International Conference e-Learning}, year={2009}, abstract={Nowadays learners have access to multiple wireless networks from the same hand held device challenging them to choose the best network in terms of cost and performance. However, the Internet billing plans are still difficult to understand, predict and control by most users. This paper presents a user oriented adaptive e-learning framework which takes into consideration: (i) the learner profile when content adaptation is done, (ii) user device that can have multiple wireless connections with different characteristics, (iii) how much the learner is willing to pay, and (iv) the network delivery performance. The goal is to ensure that the learner gets educational content that best suits his/her profile and that content will be delivered over the network which assures the best delivery performance, maintaining also a small price for getting the requested information.}, keywords={adaptive and personalised e-learning, wireless connectivity, budget, framework, user modelling}, pdf={Performance Aware And Cost Oriented Adaptive e-Learning Framework.pdf}, } </bibtex> <bibtex> @inproceedings{340, author={Genc,V.;Murphy,S.;Murphy,J.}, title={System-Level Performance Evaluation of Multi-Cell Transparent Mode Relay 802.16j Systems}, booktitle={IEEE Globecom 2009}, year={2009}, abstract={In this paper, the system capacity of a multi-cell IEEE 802.16j system operating in transparent mode is investigated. A previous published analytical model is used and incorporates interference from neighbouring cells. The model can be used to determine downlink performance under max-min fairness constraints for both sectored and omnidirectional systems with different amounts of relays. The study provides guidelines on the design of 802.16j systems operating in transparent mode – specifically, how to maximise throughput for such systems. It is shown that inter-cell interference from relays is limited in a suburban environment and that relays can deliver significant gains over single hop systems: gains of 30% and 60% can be achieved without and with spatial reuse in an omnidirectional system while 15% and 25% in a sectorised system.}, keywords={IEEE 802.16j, transparent relay, multicell, interference, spatial reuse, performance}, pdf={system level.pdf}, } </bibtex> <bibtex> @inproceedings{341, author={Holub,V.;Parsons,T.;O'Sullivan,P.;Murphy,J.}, title={Run-Time Correlation Engine for System Monitoring & Testing}, booktitle={IEEE International Conference on Autonomic Computing(ICAC-09)}, year={2009}, abstract={Today’s enterprise applications can produce vast amounts of information both during system testing and in production. Correlation of this information can be difficult as it is generally stored in a range of different event logs, the format of which can be application or vendor specific. Furthermore these large logs can be physically distributed across a number of different locations. As a result it can be difficult to form a coherent understanding of the overall system behaviour. This has implications for a number of domains (e.g. autonomic computing, system testers), where an understanding of the system behaviour at run-time is required (e.g. for problem determination, autonomic management etc.) This paper presents an approach and implementation of run-time correlation of large volumes of log data and symptom matching of known issues in the context of large enterprise applications. Our solution provides for automatic data collection, data normalisation into a common format, run-time correlation and analysis of the data to give a coherent view of system behaviour at run-time and a symptom matching mechanism that can identify known errors in the correlated data on the fly.}, keywords={System Monitoring and Testing, Event Correlation, Event Filtering}, pdf={real time.pdf}, } </bibtex> <bibtex> @inproceedings{342, author={Fallon,E.;Murphy,L.;Murphy,J.}, title={Optimising Metropolitan Area Wireless Path Selection using Media Independent Handover}, booktitle={International Workshop on Cross Layer Design}, year={2009}, abstract={The Stream Control Transmission Protocol (SCTP) is a transport layer protocol which can support mobility through its multi-homing feature. SCTP's mobility support can be subdivided into 2 areas: path performance evaluation and switch implementation. As a transport layer protocol, SCTP's path performance evaluation is limited by its end-to-end network view. In modern heterogeneous networks, it is likely that the wireless access element of an end-to-end association is the point of performance degradation. SCTP's adherence to protocol boundaries abstracts the precision and meaning of performance metrics. In this paper, we analyze how the emerging cross layer switch management approach, Media Independent Handover (MIH), can be used to optimize path selection for metropolitan area wireless broadband networks. In such an environment line of sight can easily be obstructed, causing temporary path communication failure. We investigate how Received Signal Strength (RSS) can be used as a performance indicator, which triggers MIH path migration events in such a scenario. Results are presented which illustrate that our MIH based approach has significant performance improvement over standard SCTP strategies.}, keywords={cross layer, MIH, SCTP, mobility, WiMax}, pdf={optimising.pdf}, } </bibtex> <bibtex> @inproceedings{343, author={Nowak,D.;Murphy,J.;Perry,P.}, title={Bandwidth Allocation in DiffServ Enabled Ethernet Passive Optical Networks}, booktitle={IET Communications}, year={2009}, abstract={Ethernet Passive Optical Networks (EPONs) have attracted consider- able attention from industry as they offer a simple, highly flexible and cost effective solution to the problem of providing broadband access to a customer. In this paper, a new approach to bandwidth allocation in EPONs is presented where the Optical Line Terminator (OLT) has full control over the access mechanism. This results in much simpler Optical Network Unit (ONU) architecture. It is shown in this paper that such an OLT-centric architecture offers full support for Differentiated Services and makes enforcement of Service Level Agreements possible. Extensive simulation experiments show that bandwidth allocation algorithms deployed in such a central- ized environment can deliver good performance in terms of average and maximum packet delay. In this paper two new algorithms are introduced that target SLA- aware EPONs and provide a good protection of offered quality of service against interference from other sources.}, keywords={Ethernet,LAN}, pdf={bandwidth allocation.pdf}, pdf={optimising.pdf}, } </bibtex> <bibtex> @inproceedings{449, author={C.Xu;E.Fallon;Y.Qiao;Gabriel-Miro Muntean;X.Li;A.Hanley}, title={Analysis of Real-Time Multimedia Transmission over PR-SCTP with Failover Detection Delay & Reliablity Level Diffrential}, booktitle={IEEE International Conference on Communication Software & Networks}, year={2009}, abstract={The growing availability of different wireless access technologies provides the opportunity for real-time distribution of multimedia content using multi-homing technology. Investigating the behaviors and quality of such applications under heavy network load is necessary. This paper studies the effect of path failure detection threshold and reliability level on Stream Control Transmission Protocol Partial Reliability Extension (PR-SCTP) performance in symmetric and asymmetric path conditions respectively with different path loss rates. The platform Evalvid-SCTP implemented in the University of Delaware’s SCTP ns-2 module performs the emulation experiment.}, keywords={Real-time; PR-SCTP; Evalvid-SCTP}, } </bibtex> <bibtex> @inproceedings{460, author={G.Cunningham;P.Perry;J.Murphy;L.Murphy}, title={Seamless Handover of IPTV Streams in a Wireless LAN Network}, booktitle={}, year={2009}, abstract={A robust mechanism to enable seamless handover of streamed IPTV in a WLAN is presented. Handover in a wireless network is usually based on signal strength measurements, but that approach does not consider levels of congestion within the network. Here, the case of stationary nodes with varying levels of network congestion is considered. A scheme that analyses the jitter is used to establish the relationship between congestion and loss in WLANs. This Moving Average of Negative Jitter is used as the basis of a handover scheme which can minimize loss. The handover scheme uses a client with two simultaneous connections to the same server through two separate WLANs, and it is shown that the client can compare the jitter in the two streams to determine which network delivers the best performance; this information is then used to determine when to perform a handover. The proposed scheme is implemented and results are presented that show the successful handover of an RTP over UDP stream in a live WLAN environment. The test scenario used is aimed at “Over-The-Top” service delivery, but the core algorithm is expected to be more broadly applicable.}, keywords={IPTV, Handover, Streamed Video, Wireless LAN1.}, pdf={seamless.pdf}, } </bibtex> <bibtex> @inproceedings{461, author={S.Fallon;P.Jacob;Y.Qiao;A.Hanley;L.Murphy}, title={Using 802.11 MAC Retransmission for Path Selection in Multi-Homed Transport Layer Protocols}, booktitle={IEEE Globecom}, year={2009}, abstract={The Stream Transmission Control Protocol(SCTP)is a transport layer protocol which can support mobility through its multi-homing feature. One of the key parameters used by SCTP to manage path selection is Retransmission Time Out(RTO).We illustrate that SCTP evaluation of underlying paths using end to end metrics,results is the calculation of excessive RTO for degraded wireless paths.}, keywords={SCTP,RTO,MAC Retransmissions,Mobility}, pdf={using 802.11.pdf}, } </bibtex> <bibtex> @inproceedings{462, author={C.Lamoriniere;A.Nafaa;L.Murphy}, title={Dynamic Switching Between Adaptive FEC Protocols For Multi-Source Streaming}, booktitle={}, year={2009}, abstract={Multi-source streaming is essential for the design of a large-scale P2P streaming architecture. In this paper, we focus on improving the dependability of multi-source video streaming as an alternative to the more prevalent point-to-point streaming. We have designed and implemented a dynamic FEC (D-FEC) protocol for multi-source video streaming. Our D-FEC protocol has the ability to dynamically switch between 4 different FEC techniques to adapt to varying network conditions. A comprehensive performance evaluation was performed with a full-scale system prototype that gives insights into the behavior of the different adaptive FEC schemes, and shows the feasibility of the concept of switching FEC schemes during a streaming session. Guidelines are given in order to best design a FEC protocol switching strategy taking into account the experienced loss rate, the loss burstiness, and the original video stream rate.}, keywords={P2P,FEC,Multi-Source Streaming}, pdf={dynamic switching.pdf}, } </bibtex> <bibtex> @inproceedings{463, author={Y.Yu;S.Murphy;L.Murphy}, title={Interference Aware Relay Station Location Planning for IEEE 802.16j Mobile Multi-Hop Relay Networks}, booktitle={12th ACM International Conference on Modeling Analysis & Simulation of Wireless & Mobile Systems}, year={2009}, abstract={In this paper, an interference aware algorithm for multi-cell Relay Station (RS) location planning problem is proposed in order to investigate the capacity gains possible using transparent mode 802.16j. The study focuses on the problem of determining the best choice of locations for RS from a given set of candidate sites - Base Station (BS) and Subscriber Station (SS) locations are assumed given. The proposed algorithm evaluates each RS based on the channel conditions of the links between the RS and its surrounding Subscriber Stations(SS) and the throughput gain it could deliver, taking into account co-channel interference. The performance statistics were collected over a large amount of experiments with many different configurations, including Base Station(BS) antenna types, number of candidate RS sites, RS transmitting power, with/without spatial reuse, etc. The results can be divided into two sections. Firstly, the algorithm was tested for optimality and scalability and was shown to perform well compared to classical Integer Programming solution techniques. Secondly, the results generated by the algorithm when applied to different scenarios were analyzed. Results show that using spatial reuse could achieve a much higher throughput gain, 3-5 time, then without using spatial reuse, although sectorised BS antenna limits the separation of co-channel RSs in a sector. The results demonstrate the characteristics of the trade-off between number of RSs and throughput gain for different configurations.}, keywords={IEEE 802.16j, Spatial Reuse, Network Planning, Relay Station Location Problem}, pdf={interference aware.pdf}, } </bibtex> <bibtex> @inproceedings{468, author={Scotton, J.; Moebs, S,; McManis, J.; Cristea, A.I.}, title={A Case Study on Merging Strategies for Authoring QoE-based Adaptive Hypermedia}, booktitle={ECTEL 2009}, year={2009}, abstract={This paper describes recent work on strategy merger development in the authoring process of adaptive hypermedia. The goal of a merging strategy is to break a complex adaptation decision into a number of simpler ones which may be reused more easily and applied in different orders. To demonstrate the proposed method we present an example case study and sample strategies written in the LAG language. The case study is based on a recently proposed model for Quality of Experience in e-learning. This model exposes the complex interaction between a number of factors affecting QoE and hence presents a good candidate for the application of a strategy merger. Finally some evaluation points are identified, a conclusion is drawn and next steps are outlined.}, keywords={LAG, Quality of Experience, Quality of Service, Multimedia Learning, Educational Adaptive Hypermedia, Adaptation, Strategy merger}, pdf={A3H09Paper_FinalPostReviewChanges_ScottonMoebsMcManisCristea.pdf}, } </bibtex> <bibtex> @inproceedings{469, author={Andreea Molnar; Cristina Hava Muntean}, title={Billing Issues when Accessing Personalised Educational Content}, booktitle={China-Ireland International Conference on Information and Communications Technologies (CIICT 2009)}, year={2009}, abstract={The increased affordability of mobile devices combined with the availability of the latest wireless technologies have made mobile devices an attractive tool for learning. Nowadays learners can choose between multiple wireless networks with different characteristics, belonging to the same or to different mobile operators. Unfortunately, the Internet billing plans are still difficult to predict and control by most users. This paper presents an algorithm which aims to determine the best network, from a list of available ones (in terms of price), for delivering the selected educational content.}, keywords={cost, mobile data billing plan, mobile learning, adaptive and personalised learning}, } </bibtex> <bibtex> @inproceedings{470, author={Andreea Molnar; Cristina Hava Muntean}, title={QoE-MOT – A Learner Quality of Experience- Oriented Authoring Tool}, booktitle={European Conference on Technology Enhanced Learning, A3H: 7th International Workshop on Authoring of Adaptive and Adaptable Hypermedia}, year={2009}, abstract={This paper introduces Quality of Experience My Online Teacher (QoE-MOT), a user quality of experience oriented version of the generic authoring tool MOT. QoE-MOT is an authoring tool which enables the creation of performance-aware adaptive courses, by adapting the educational content to the learner network conditions. MOT was developed based on LAOS, a complex five layer authoring model. In similar fashion, QoE-MOT was constructed following the QoE-LAOS, a learner quality of experience oriented authoring model. This paper illustrates how an adaptive educational course has been enhanced with performance oriented metadata and how this metadata and QoE parameters are used during the adaptation process.}, keywords={Authoring tool, Adaptive e-learning, LAOS, QoE, MOT, LAG}, pdf={QoE-MOT.pdf}, } </bibtex> <bibtex> @inproceedings{109, author={Sabine Moebs; Jennifer McManis}, title={A Learner, is a Learner, is a User, is a Customer - So what exactly do you mean by Quality of Experience?}, booktitle={Adaptive Hypermedia and Adaptive Web-based Systems}, year={2008},

abstract={An e-learner’s Quality of Experience (QoE) is informed by previous experiences as a learner, a user of computer/web-based systems, and a customer. This paper surveys different concepts for Quality of Experience (QoE) from different areas such as psychology, internet marketing, web engineering, systems and product development as well as philosophy of education. They are summarized into a proposal for a definition of Learner QoE in adaptive multimedia e-learning systems. A number of factors are identified that are likely to impact on QoE. We propose a <st1:place w:st="on">Delphi</st1:place> study to be used to provide an initial ranking of the importance of these factors. Additional user testing will be required to confirm the findings of this study.

 

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keywords={adaptive hypermedia, quality of experience, educational philosophy}, pdf={ah_ws6_moebs_mcmanis.pdf}, } </bibtex> <bibtex> @inproceedings{162, author={C. Thorpe; S. Murphy; L. Murphy}, title={Analysis of Variation in IEEE802.11k Channel Load Measurements for Neighbouring WLAN Systems}, booktitle={ICT Mobile Summit}, year={2008}, abstract={This paper focuses on analysing the variation in IEEE802.11k channel load measurements for neighbouring WLAN systems. The channel load functionality was implemented in the QualNet simulation tool, and several scenarios were configured for testing. The effects of different numbers of active systems with different traffic patterns were examined. The results obtained indicate significant variation in channel load values calculated by different stations experiencing different levels of interference. This variation leads us to question the usefulness of a single channel load measurement; hence considerable care must be taken when using and interpreting such measurements. }, keywords={IEEE802.11k, Channel Load Measurements, Interference}, pdf={ICTMobileSummit_Paper_Camera_Ready.pdf}, } </bibtex> <bibtex> @inproceedings{183, author={Sabine Moebs}, title={A Learner, is a Learner, is a User, is a Customer - QoS-based Experience-aware Adaptation}, booktitle={ACM Multimedia}, year={2008}, abstract={This paper describes an outline of the doctoral thesis work concerning adaptation policies towards quality of experience (QoE) in performance-aware adaptive multimedia e-learning systems. QoE is considered to be mainly affected by the psychological concept of flow and learning-related factors. In turn, for multimedia systems, these factors can be heavily influenced by quality of service (QoS). In an ideal world, QoS would not be an issue and content optimally tailored to a user’s needs could always be perfectly delivered. Unfortunately, delivery conditions are not always ideal, and it may be infeasible to deliver certain multimedia content such as high quality video while maintaining an acceptable QoS. The goal of this research is to balance the constraints imposed by QoS restrictions with the requirements of flow and learning in order to produce the highest possible QoE for the learner using an adaptive multimedia system.}, keywords={Algorithms, Performance, Design, Human Factors, QoE, QoS, Flow, Learning}, pdf={smoebs_multimedia2008_ds.pdf}, } </bibtex> <bibtex> @inproceedings{184, author={S. Moebs; J. McManis}, title={ADAPTIVE SOCIAL CONNECTEDNESS IN A MULTIMEDIA E-LEARNING ENVIRONMENT}, booktitle={China-Ireland Conference on ICT (CIICT)}, year={2008}, abstract={Adaptive hypermedia systems are beneficial to e-learners in tailoring content to individual characteristics such as prior knowledge, learning preferences, etc. However, unlike popular non-adaptive learning management systems such as Moodle and Blackboard they do not support social connectedness by allowing communication with other learners. This can lead to feelings of isolation amongst learners and ultimately learner demotivation. Enabling communication has been shown to improve cohesion within a learner group and allows a tutor to monitor learner participation and intervene before learners become disengaged. This paper outlines a stand-alone component connect! for the selection of multimedia communication tools in adaptive e-learning systems to support social connectedness. In addition to the already proven benefits of supporting social interaction, attaching such a module to an adaptive hypermedia system allows us to introduce the novel feature of tailoring the communication method to the individual needs of the learner. We draw on research in the area of media ecology to assist us in making our decisions.}, keywords={adaptive systems, social connectedness}, pdf={moebs_mcmanis_adaptive_social_connectedness_final.pdf}, } </bibtex> <bibtex> @inproceedings{186, author={Seung-Bum Lee;Gabriel-Miro Muntean;Alan F. Smeaton}, title={Smart PIN: Utility-based Replication and Delivery of Multimedia Content to Mobile Users in Wireless Networks.}, booktitle={IEEE International Symposium on Broadband Multimedia Systems and Broadcasting 2008: Mobile and Handheld Systems for Entertainment on the Go}, year={2008}, abstract={Next generation wireless networks rely on heterogeneous connectivity technologies to support various rich media services such as personal information storage, file sharing and multimedia streaming. Due to users mobility and dynamic characteristics of wireless networks, data availability in collaborating devices is a critical issue. In this context Smart PIN was proposed as a personal information network which focuses on performance of delivery and cost efficiency. Smart PIN uses a novel data replication scheme based on individual and overall system utility to best balance the requirements for static data and multimedia content delivery with variable device availability due to user mobility. Simulations show improved results in comparison with other general purpose data replication schemes in terms of data availability.}, keywords={Content management, Non-real-time service, Interactive systems, Mobile systems, Portable and handheld devices}, } </bibtex> <bibtex> @inproceedings{187, author={Seung-Bum Lee;Gabriel-Miro Muntean;Alan F. Smeaton}, title={User-centric Utility-based Data Replication in Heterogeneous Networks.}, booktitle={IEEE International Conference on Communications, Workshop on Digital Television and Mobile Multimedia Broadcasting (ICC 2008)}, year={2008}, abstract={Information overload and convergence of devices aggravate the difficulties of accessing data distributed among various user devices especially when this is performed by mobile users and over heterogeneous wireless networks. Existing data replication systems help increase the performance of the distributed data system, but they do not consider users different levels of interest in various pieces of data and neither heterogeneous wireless connectivity issues. This paper presents the Smart Personal Information Network (Smart PIN), a performance and cost-aware personal information network which uses a novel usercentric utility-based data replication scheme to exchange content automatically, based on both network performance and user interests. The proposed user-centric data replication scheme s evaluation, through simulation, shows improved results in comparison with existing solutions.}, keywords={ Data replication, Utility Function, Heterogeneous Network}, } </bibtex> <bibtex> @inproceedings{193, author={Bogdan Ciubotaru; Gabriel-Miro Muntean}, title={M3S - Multimedia Mobility Management and Load Balancing in Wireless Broadcast Networks}, booktitle={China-Ireland International Conference on Information and Communications Technologies 2008 (CIICT 2008)}, year={2008}, pages={515-521}, abstract={Wireless local-area networks represent a viable broadband Internet access solution for enterprise, residential and public areas. Due to its short range radio, multiple wireless access points are necessary to cover a certain physical area. The tendency of mobile users to group in certain areas of interest and of mobile devices to connect to the access point with the highest signal strength determines the overall network load to be highly unbalanced. To overcome this issues which drastically affects user bandwidth share as well as the efficiency of network resource utilization, special load balancing techniques has to be employed. This paper presents the Multimedia Mobility Management System (M3S), a quality oriented mobility management framework which aims at maximizing user perceived multimedia quality by efficiently distributing the traffic load over all the communication resources available. Simulation based testing results are presented, outlining the performance of M3S against other load balancing techniques which rely on mobile device re-association with least congested access points.}, keywords={wireless broadcast networks, load balance, mobility management}, pdf={Ciubotaru_Muntean_CIICT08.pdf}, } </bibtex> <bibtex> @inproceedings{218, author={J. Fitzpatrick, S. Murphy, M. Atiquzzaman, J. Murphy}, title={ECHO: A Quality of Service based Endpoint Centric Handover scheme for VoIP}, booktitle={Wireless Communications and Networking Conference (WCNC)}, year={2008}, abstract={Existing terminal oriented handover mechanisms capable of meeting the strict delay bounds of real time applications such as VoIP do not consider the QoS of candidate handover networks. In this paper ECHO – a QoS based handover solution for VoIP– is proposed. ECHO is endpoint centric and does not require any network support; it leverages the SCTP transport protocol. ECHO incorporates network metrics that directly affect VoIP quality into the handover decision process. A dynamic variant of the ITU-T E-Model is used to calculate how the network metrics map to a user perceived voice quality metric known as the MOS. The MOS value is then used to make handover decisions between each of the available access networks. The results show that the addition of the QoS capabilities significantly improves the handover decisions that are made.}, keywords={ECHO, QoS, E-Model, SCTP, Handover, VoIP}, } </bibtex> <bibtex> @inproceedings{223, author={Yang Yu;Sean Murphy;Liam Murphy}, title={A Clustering Approach to Planning Base Station and Relay Station Locations in IEEE 802.16j Multi-hop Relay Networks}, booktitle={Proc. IEEE International Conference on Communications (ICC 2008)}, year={2008}, abstract={In this paper, a clustering approach to solve a network planning problem for 802.16j relay networks is considered. Our clustering approach consists of three basic steps: (1) divide the nodes into k distinct clusters, (2) solve the planning problem separately for each cluster, and (3) perform a final optimization to reduce issues arising at cluster boundaries. Simulation results show that our approach is more efficient than existing approaches: solutions of equivalent quality can be found in 40% of the time. Thus our technique can be used to solve larger problems with similar hardware, or similar size problems in less time.}, keywords={network planning,802.16j,Wimax,relay network,clustering}, } </bibtex> <bibtex> @inproceedings{224, author={Yang Yu;Sean Murphy;Liam Murphy}, title={Planning Base Station and Relay Station Locations in IEEE 802.16j Multi-hop Relay Networks}, booktitle={Proc. 2nd IEEE Broadband Wireless Access Workshop, colocated with IEEE CCNC 2008}, year={2008}, abstract={In this paper, a problem formulation for determining optimal node location for Base Stations (BSs) and Relay Stations (RSs) in relay-based 802.16 networks is developed. The formulation results in an Integer Programming problem. A small modification to the original model is also considered in which the state space is reduced by limiting which nodes can be associated with which. Standard branch and bound techniques are used to solve the problem. The key findings of the paper are that standard techniques can be used to find solutions to problems of small metropolitan scale or for areas within a larger city.}, keywords={network planning,802.16j,Wimax,relay network}, } </bibtex> <bibtex> @inproceedings{230, author={Vasken Genc; Sean Murphy; John Murphy}, title={An Interference-Aware Analytical Model for Performance Analysis of Transparent Mode 802.16j Systems}, booktitle={Broadband Wireless Access Workshop co-located with GLOBECOM}, year={2008}, abstract={In this paper, an interference-aware analytical model of IEEE 802.16j systems operating in transparent mode is described. The model can be used to determine the throughput gain that can be achieved by 802.16j relay- based systems under a max-min fairness constraint in which the difference between the data rate delivered to all subscribers is minimized. Two variants of the model are considered – one in which there is no spatial reuse and one in which there is spatial reuse. The study finds that this variant of 802.16j system can deliver significant gains over traditional single-hop access systems: 40% in the case in which there is no spatial reuse and up to 80% when spatial reuse is realised.}, keywords={IEEE 802.16j, optimisation problem, performance gain, transparent multihop relay}, pdf={camerayready-BWA08.pdf}, } </bibtex> <bibtex> @inproceedings{231, author={Vasken Genc; Sean Murphy; John Murphy}, title={Performance Analysis of Transparent Relays in 802.16j MMR Networks}, booktitle={WiOpt}, year={2008}, abstract={A simulation study of the performance of transparent mode relay-based 802.16j systems is described. The study focuses on the gain in throughput that is possible in omnidirectional relay systems and increases in signalling requirements that arise due to the multihop network architecture. The study finds that the introduction of transparent mode relays cannot deliver improved throughput for a substantial part of the coverage area of a Base Station (BS) – only approximately half of the total area covered by the BS can benefit from throughput enhancement. Further, the study shows that 802.16j based systems require significant signalling overhead, with almost twice that of 802.16e in the cases studied. Finally, the study demonstrates that in a topology with users uniformly distributed within the BS cell coverage, the maximum throughput increase on the downlink that can be achieved is relatively low. Much further work is necessary to realise useful gains from these systems.}, keywords={MMR, transparent multihop relay, performance, omnidirectional antenna}, pdf={wiopt08-cameraready.pdf}, } </bibtex> <bibtex> @inproceedings{331, author={Parsons,T.;Mos,A.;Murphy,J.;Trofin,M.;Gschwind,T.}, title={Extracting Interactions in Component Based Systems}, booktitle={IEEE Transactions on Software Engineering}, year={2008}, abstract={Monitoring, analysing and understanding component based enterprise software systems are challenging tasks. These tasks are essential in solving and preventing performance and quality problems. Obtaining component level interactions which show the relationships between different software entities is a necessary prerequisite for such efforts. This paper focuses on component based Java applications, currently widely used by industry. They pose specific challenges while raising interesting opportunities for component level interaction extraction tools. We present a range of representative approaches for dynamically obtaining and using component interactions. For each approach we detail the needs it addresses, and the technical requirements for building an implementation of the approach. We also take a critical look at the different available implementations of the various techniques presented. We give performance and functional considerations and contrast them against each other by outlining their relative advantages and disadvantages. Based on this data, developers and system integrators can better understand the current state of the art and the implications of choosing or implementing different dynamic interaction extraction techniques.}, keywords={Distributed objects, components, containers, tracing.}, pdf={extracting.pdf}, } </bibtex> <bibtex> @inproceedings{332, author={Alocci,I.;Murphy,S.;Nafaa,A.;Murphy,J.}, title={Development of an IEEE 802.11s Simulation Model for QualNet}, booktitle={Networking & Electronic Commerce Research Conference}, year={2008}, abstract={In this work, an initial variant of an 802.11s simulation model for the QualNet simulator is described. The tool builds on the existing QualNet 802.11 model by adding capabilities suitable for mesh networking. More specifically, the model provides support for propagation of beacon frames in mesh networks and link establishment procedures by which nodes attach to the network.}, keywords={Networking,QOS}, pdf={development.pdf}, } </bibtex> <bibtex> @inproceedings{333, author={Qiao,Y.;Fallon,E.;Murphy,L.;Murphy,J.;Hanley,A.}, title={Path Selection of SCTP Fast Retransmission in Multi-Homed Wireless Environments}, booktitle={13th IFIP International Conference on Personal Wireless Communications}, year={2008}, abstract={In heterogeneous wireless network environments, network connections of a device may have a significant differential. This paper studies the effect of path bandwidth differential on the performance of fast retransmission strategies in Multi-homing environments. It identifies that fast retransmission on an alternate path may cause receive buffer blocking when path bandwidth differential is significant and the receive buffer is limited. A theoretical model is proposed for selecting retransmission path during the fast retransmission phase, which is based on receive buffer and path conditions. The model is verified through simulations with various path differentials.}, keywords={Wireless Communication}, pdf={path selection.pdf}, } </bibtex> <bibtex> @inproceedings{335, author={Fallon,E.;Murphy,L.;Murphy,J.}, title={An Analysis of the Performance of an MIH Based Switch Strategy for Heterogenous Network Mobility}, booktitle={IEEE 17th IST Mobile & Wireless Communications Summit}, year={2008}, abstract={The increasingly ubiquitous deployment of wireless networks has created significant opportunities for mobile application developers. The availability of highcapacity, low financial cost networks has the potential to enable mobile application developers to offer feature-rich end-user-oriented product offerings. Standardisation efforts such as Media Independent Handover (MIH) will support this trend by providing developers with a detailed view of the financial cost and performance capabilities of available wireless and mobile networks. Even with the increasingly pervasive deployment of Wireless LAN (WLAN), it is unlikely those mobile applications will exclusively utilise WLAN networks, as many are deployed without consideration of seamless network mobility. In the scenario where WLAN coverage gaps exist, it will be necessary to utilise mobile networks such as UMTS as a communication bridge. In such an environment, the mobility support provided by multi-homed protocols such as the Stream Control Transmission Protocol (SCTP) has significant potential. This paper investigates how MIH performance characteristics - in particular the Received Signal Strength (RSS) from a WLAN Access Point (AP) - can be used to optimise SCTP switch performance. Results indicate that in certain situations there is a performance problem with utilising a "retransmit on same path" approach to lost packet retransmission when the primary path is explicitly set, as would be the case with MIH. Careful configuration of the RSS threshold for switchover is shown to alleviate the problem.}, keywords={SCTP, WLAN, Network Migration}, pdf={an analysis.pdf}, } </bibtex> <bibtex> @inproceedings{436, author={B.Ciubotaru;Gabriel-Miro Muntean}, title={M3S-Multimedia Mobility Management & Load Balancing in Wireless Broadcast Networks}, booktitle={IET Chine-Ireland International Conference on Information & Communications Technology}, year={2008}, abstract={Wireless local-area networks represent a viable broadband Internet access solution for enterprise, residential and public areas. Due to its short range radio, multiple wireless access points are necessary to cover a certain physical area. The tendency of mobile users to group in certain areas of interest and of mobile devices to connect to the access point with the highest signal strength determines the overall network load to be highly unbalanced. To overcome this issues which drastically affects user bandwidth share as well as the efficiency of network resource utilization, special load balancing techniques has to be employed. This paper presents the multimedia mobility management system (M3S), a quality oriented mobility management framework which aims at maximizing user perceived multimedia quality by efficiently distributing the traffic load over all the communication resources available. Simulation based testing results are presented, outlining the performance of M3S against other load balancing techniques which rely on mobile device re-association with least congested access points}, keywords={Multimedia,Wireless Networks,Mobile Communication}, } </bibtex> <bibtex> @inproceedings{446, author={C.Xu;Gabriel-Miro Muntean;E.Fallon;A.Hanley;F.Karayel}, title={A Balanced Tree-based Strategy for Unstructured Media Distribution in P2P Networks}, booktitle={IEEE International Conference on Communication}, year={2008}, abstract={Most research on P2P multimedia streaming assumes that users access video content sequentially and passively. Unlike P2P live streaming in which the peers start playback from the current point of streaming when they join the streaming session, in P2P video-on-demand streaming VCR-like operations such as forward, backward, and random-seek have to be supported. Providing this level of interactive streaming service in a P2P environment is a significant challenge. This paper proposes a Balanced Binary Tree-based strategy for Unstructured video-ondemand distribution in P2P networks (BBTU). BBTU assumes videos can be divided into several segments which can be fetched from different peers. BBTU involves two steps: 1) balance binary tree construction based on a prefetching algorithm in order to support interactivity; 2) unstructured video dissemination over network based on gossip protocol, which is the overlay for video distribution. Analysis and simulation show how BBTU is an efficient interactive streaming solution in P2P environment.}, keywords={P2P video-on-demand; interactivity; balanced}, pdf={a balanced.pdf}, } </bibtex> <bibtex> @inproceedings{447, author={C.XU;Gabriel-Miro Muntean;E.Fallon;X.Li}, title={DONET-VOD:A Hybrid Overlay Solution for Efficient Peer-to-Peer Video on Demand Services}, booktitle={IEEE International Conference on Multimedia & Expo(ICME)}, year={2008}, abstract={The existing DONet-based approach uses successfully a random gossip algorithm for scalable live video streaming. This pure mesh overlay network-based solution may lead to unacceptable latency or even failure of VCR operations in Video-on-Demand (VoD) services where nodes usually have different playing offsets, across a wide range. This paper proposes DONet-VoD which enhances DONet in order to address issues related to VoD delivery and VCR operations. In DONet-VoD, DONet principle is employed for the video distribution over the overlay network and a novel algorithm which uses a multi-way tree structure and extra prefetching buffers at the nodes is proposed to support efficient VoD operations. Video segments are prefetched and stored in a distributed manner in the nodes’ prefetching buffer along the tree. The cooperation between DONetbased video delivery and the tree-located multimedia components enable multimedia streaming interactive commands to be performed efficiently. This paper presents and discusses the prefetching scheme, details the cooperation procedure, and then analyses the performance of the proposed DONet-VoD}, keywords={Peer-to-peer, VoD, prefetching, multiway}, pdf={donet.pdf}, } </bibtex> <bibtex> @inproceedings{448, author={C.Xu;Y.Qiao;E.Fallon;Gabriel-Miro Muntean}, title={Comparitive Study of Real-Time Multimedia Transmission over Multi-Homing Transport Protocols}, booktitle={IEEE /IFIP International Conference on Management of Multimedia Networks & Services}, year={2008}, abstract={The availability of multimedia applications suitable for deployment using 3G and GPRS networks has led to a requirement for end-to-end quality of service. More efficient mechanisms are needed in order to provide the required end user quality of service in wireless data networks. This paper investigates the performance implications of transmitting real-time multimedia content over a multi-homed transport protocol in a manner which is tolerant of network failure. It evaluates video quality with different retransmission policies combined with various path failure detection thresholds, path bandwidths, delays and loss rate conditions through Partial Reliable Stream Control Transmission Protocol (PRSCTP). A solution called Evalvid-SCTP, which is a trace driven simulation of MPEG-4 video over SCTP, was designed to achieve the performance evaluation.}, keywords={PR-SCTP, Multi-homing, MPEG-4 Video, Congestion Control}, pdf={comparitive study.pdf}, } </bibtex> <bibtex> @inproceedings{185, author={Seung-Bum Lee;Gabriel-Miro Muntean;Alan F. Smeaton}, title={Cost-oriented Context and Content Data Pair Delivery in Smart PIN}, booktitle={China-Ireland International Conference on Information and Communications Technologies}, year={2007}, pages={97-204}, abstract={With evolutions of wireless technologies and advances in mobile services, ubiquitous devices have huge acquired and storing data which requires metadata for user to handle easily. For this purpose, this paper introduces Smart PIN - a novel performance and cost-oriented, context-aware personal information network. Smart PIN architecture includes network components, service components and management components. At the service components, there should be consideration for service discovery, service composition, data replication management and data pair transfer. Among these issues, this paper proposes a novel scheme for efficient delivery of context and content data based on pull and push scheme controlling logical and physical cost function.}, keywords={Context-awareness, Data replication, Cost-effectiveness, Wireless PAN}, } </bibtex> <bibtex> @inproceedings{216, author={S. Murphy, M. Atiquzzaman, J. Fitzpatrick, J. Murphy}, title={Terminal-oriented solutions for seamless service delivery via heterogeneous radio access networks (Invited Paper)}, booktitle={Sarnoff Symposium 2007}, year={2007}, abstract={In this paper, options for providing seamless service delivery to mobile terminals via heterogeneous radio access networks are considered. Despite its current popularity, the Mobile IP solution for mobility management of mobile hosts is discounted due to problems associated with introducing the required network infrastructure and poor handover performance. Rather, the solution described here comprises of a number of key technologies working together. More specifically, the paper argues that the most appropriate solution comprises of the following: adaptive applications, an abstraction layer between application and transport layer, an intelligent transport layer with multi-homing and multi-path support and a means to obtain current state information about each of the available access networks. While work has been ongoing on each of these individual components little has been done to address how they can all be integrated and consider how they may perform in the context of different radio access technologies, potentially operated by different entities. This paper attempts to address some of these issues.}, keywords={Heterogeneous wireless access networks, Handover, Mobile Networking}, } </bibtex> <bibtex> @inproceedings{217, author={J. Fitzpatrick, S. Murphy, M. Atiquzzaman, J. Murphy}, title={Evaluation of VoIP in a Mobile Environment using an SCTP based Handoff Mechanism}, booktitle={IST Mobile Summit}, year={2007}, abstract={In parallel with the growth of VoIP services, a large number of manufacturers have begun to develop multimode devices capable of connecting to multiple wireless access networks simultaneously. These multimode terminals have, in principle, the capability to support seamless handover between different radio access networks. One handover solution that utilises the IP diversity which these multimode devices can deliver is SIGMA. SIGMA is a promising end-to-end transport layer handover solution based on SCTP. The objective of this paper is to investigate if SIGMA is capable of providing seamless handover of VoIP calls without degradation in voice quality. To achieve this, we developed a Linux based testbed on which we implemented a VoIP client and server using SIGMA handoff . Each voice call uses the G.711 voice codec over RTP. PR-SCTP is used in place of the traditional UDP as the transport layer protocol. SIGMA based handover was used during full duplex voice calls between the client and server. The ITU-T E-Model has been used to calculate the voice quality during the handover. Results show that SIGMA can be used as a seamless handover mechanism for VoIP without any impact on voice quality.}, keywords={SCTP, VoIP, SIGMA, Seamless Handover}, } </bibtex> <bibtex> @inproceedings{233, author={Odd Inge Hillestad; Andrew Perkis; Vasken Genc; Sean Murphy; John Murphy}, title={Adaptive H.264/MPEG-4 SVC video over IEEE 802.16 Broadband Wireless Networks}, booktitle={Packet Video}, year={2007}, abstract={In this paper we present a solution for delivering streaming video-on-demand to subscribers via an 802.16 broadband wireless access network. The solution leverages the forthcoming H.264/AVC Scalable Video Coding (SVC) scheme and a mechanism to perform rate adaptation based on monitoring changes to the amount of flow traffic in the network at any time. A simulation-based approach is used to determine how the system performs in a rural deployment. Results show that the scheme provides high utilization of the wireless access system, at over 96%. Further, it maintains smooth transmission rate for the video applications, and ensures that no interruptions in continuous video playback occur during the streaming session. Lastly, a comparison with single-layer H.264/AVC is performed, showing how the proposed solution performs better with respect to both system utilization and the fact that no clients suffer interruptions in continuous playback.}, keywords={IEEE 802.16, video streaming, scalable video coding}, } </bibtex> <bibtex> @inproceedings{322, author={Ormond,O.;Murphy,J.;Muntean,G.}, title={Dynamic Network Selection in Wireless LAN/MAN Heterogenous Networks}, booktitle={Mobile WiMAX:Toward Broadband Wireless Metropolitan Area Networks}, year={2007}, abstract={In future generations of wireless networks, it is expected that different users with various multi-homed personal wireless devices will have the option of accessing their desired services via different available radio access networks. Given the variability of the radio environment properties and user mobility, the availability and characteristics of an access network will change in time and are highly dependent on location. As a result, dynamic reselection of the access network will be a necessary part of the mobility management mechanism (which maintains the session connectivity as the user moves and/or the available access characteristics change). In their selection of a radio access network customers will consider cost and perceptive quality preferences for the current application and will rely on intelligent network selection decision strategies to aid or automate their choice. These dynamic selection strategies will need to take into account different dynamic, and sometimes conflicting, metrics}, keywords={Wireless Communication}, pdf={dynamic network.pdf}, } </bibtex> <bibtex> @inproceedings{323, author={Carrig,B.;Denieffe,D.;Murphy,J.}, title={A Non-Elevated Scheduling Solution for First Person Shooter Games in IEEE 802.11 Networks}, booktitle={IEEE Globecom 2007}, year={2007}, abstract={First Person Shooter (FPS) games are a popular online gaming genre played predominately over wired networks. FPS games are highly interactive and have stringent delay requirements. However, the explosive growth in wireless LAN (WLAN) deployment has seen an increase in the use of such networks for gaming purposes. The varied performance of the IEEE 802.11 MAC Distributed Coordination Function (DCF) has tended to make WLANs unsuitable for FPS games. The IEEE 802.11e standard introduces Quality of Service (QoS) mechanisms including Enhanced Distributed Channel Access (EDCA) allowing prioritization of competing flows. Using the NS- 2 simulator, we evaluate the capability of 802.11g and 802.11e WLANs to support Quake IV games traffic in the presence of web traffic. We compare the results achieved using EDCA with those achieved by a non-elevated differentiated services scheduler known as Best Effort with Loss Trade-off (BELT). We find that the BELT scheduler compares favorably with EDCA in this context.}, keywords={Online Gaming,LAN,QOS}, pdf={non elevated.pdf}, } </bibtex> <bibtex> @inproceedings{324, author={Carrig,B.;Denieffe,D.;Murphy,J.}, title={A Congestion-only Charging Mechanism for Multiplayer Gaming in Diffrentiated Service Networks}, booktitle={IEEE Globecom 2007}, year={2007}, abstract={In networks based on the Di®erentiated Services (Di®Serv) architecture, users may be presented the opportunity to choose their Assured Forwarding (AF) class. Users will attempt to maximize their Consumer Surplus (CS) in such an environment. They can increase their CS by choosing the lowest cost AF class that satis¯es their Quality of Service (QoS) requirements. Previously the authors have proposed an algorithm known as Consumer Surplus Maximization (CSM) [2]. Although this algorithm improves CS for users, widespread adoption of the algorithm can provoke network instability. If many users switch classes at once, degradation on one AF class can easily propagate. The likelihood of such an occurrence can be reduced by replacing ¯xed per- byte or per-packet charges associated with individual AF classes with a lightweight Congestion-only Charging (CoC) pricing mechanism. An additional charge is only applied to packets that receive discernible bene¯t from belonging to a particular class. We present simulation results from a networking scenario where users connect across a single Di®Serv domain to engage in a multiplayer First Person Shooter (FPS) game.}, keywords={Pricing, Quality of Service, Di®Serv}, pdf={congestion only.pdf}, } </bibtex> <bibtex> @inproceedings{325, author={Murphy,L.;Noonan,J.;Perry,P.;Murphy,J.}, title={An Application-quality based Mobility Management Scheme}, booktitle={9th International Conference on Mobile & Wireless Communication Networks}, year={2007}, abstract={Experimental results are presented for end-point controlled handover of a stream of voice-like packet data traffic between two independent wireless networks. The handover was achieved by using a version of the Stream Control Transmission Protocol (SCTP) that had been modified to monitor link quality and switch the primary connection to the “best” quality link available, where quality is evaluated in terms of application performance. The results clearly show that mobility management based solely on received signal strength is not suitable for wireless systems with contention-based access policies such as WiFi.}, keywords={Mobile Communication, Network Testing, Packet Radio, Wide area networks, Wireless LAN, Handover, VoIP, Call Quality}, pdf={application-quality.pdf}, } </bibtex> <bibtex> @inproceedings{326, author={Carrig,B.;Denieffe,D.;Murphy,J.}, title={Supporting First Person Shooter Games in Wireless Local Area Networks}, booktitle={IEEE 18th International Symposium on Personal,Indoor & Mobile Radio Communications}, year={2007}, abstract={First Person Shooter (FPS) games are a popular online gaming genre played predominately over wired networks. FPS games are highly interactive and have stringent delay requirements. However, the explosive growth in wireless LAN (WLAN) deployment has seen an increase in the use of such networks for gaming purposes. The varied performance of the IEEE 802.11 MAC Distributed Coordination Function (DCF) has tended to make WLANs unsuitable for FPS games. The IEEE 802.11e standard introduces Quality of Service (QoS) mechanisms including Enhanced Distributed Channel Access (EDCA) allowing prioritization of competing flows. Using the NS-2 simulator, we evaluate the capability of 802.11g and 802.11e WLANs to support Quake IV games traffic in the presence of web traffic. We compare the results achieved using EDCA with those achieved by a non-elevated differentiated services scheduler known as Best Effort with Loss Trade-off (BELT). We find that the BELT scheduler compares favorably with EDCA in this context.}, keywords={Online Gaming,LAN,QOS,IEEE 802.16}, pdf={supporting first.pdf}, } </bibtex> <bibtex> @inproceedings{327, author={Carrig,B.;Denieffe,D.;Murphy,J.;OSE,D.}, title={Congestion-only Charging: A Novel PricinG Mechanism for use in Diffrentiated Service Networks}, booktitle={ACM 4th International Conference on Heterogenous Networking for Quality,Reliablity,Security & Robustness,Qshine2007}, year={2007}, abstract={In networks based on the Di®erentiated Services (Di®Serv) architecture, users may be presented the opportunity to choose their Assured Forwarding (AF) class. Users will attempt to maximize their Consumer Surplus (CS) in such an environment. They can increase their CS by choosing the lowest cost AF class that satis¯es their Quality of Service (QoS) requirements. Previously the authors have proposed an algorithm known as Consumer Surplus Maximization (CSM) [2]. Although this algorithm improves CS for users, widespread adoption of the algorithm can provoke network instability. If many users switch classes at once, degradation on one AF class can easily propagate. The likelihood of such an occurrence can be reduced by replacing ¯xed per- byte or per-packet charges associated with individual AF classes with a lightweight Congestion-only Charging (CoC) pricing mechanism. An additional charge is only applied to packets that receive discernible bene¯t from belonging to a particular class. We present simulation results from a networking scenario where users connect across a single Di®Serv domain to engage in a multiplayer First Person Shooter (FPS) game.}, keywords={Pricing, Quality of Service, DiffServ}, pdf={congestion novel.pdf}, } </bibtex> <bibtex> @inproceedings{328, author={Qiao,Y.;Fallon,E.;Murphy,L.;Murphy,J.;Hanley,A.;Zhu,X.;Matthews,A.;Conway,E.}, title={SCTP Performance Issue on Path Delay Diffrential }, booktitle={WWIC 5th International Conference on Wired/Wireless Internet Communications}, year={2007}, abstract={This paper studies the effect of path delay on SCTP performance. It focuses on the SCTP fast retransmit algorithm and demonstrates that the performance in the current retransmission strategy will degrade acutely when the secondary path delay is less than the primary path delay at a certain level. The performance degradation is due to the disordered SACKs and constant congestion window size during the fast retransmit phase. Some modifications aimed at these problems are proposed and evaluated. This paper also identifies that the cause of the performance degradation in SCTP is a result of the single path configuration oriented design of the current fast retransmit algorithm. Several fast retransmission strategies are evaluated for different path delay and bandwidth configurations.}, keywords={SCTP, Multi-homing, Retransmission strategy, Path difference.}, pdf={sctp.pdf}, } </bibtex> <bibtex> @inproceedings{329, author={Hnetynka,P.;Murphy,J.}, title={Deployment of Java Based Components in Embedded Environment}, booktitle={International Conference Applied Computing}, year={2007}, abstract={Component-based development has brought the benefits of easier reuse, integration and rapid development into the software engineering process. Many contemporary component-based platforms (e.g. EJB, CCM, SOFA, Fractal) are implemented in Java because of Java features such as platform independence, dynamic loading, type safety, and others. Another reason is that Java becomes more and more ubiquitous as devices like mobile phones, PDAs, etc. embed the Java implementation. However in the area of embedded systems, applications are usually still monolithic and therefore hard to maintain and reuse. On the other hand, the embedded Java platform has several important limitations, which prevent straightforward reuse of component-based platforms. In this paper, we present how to overcome these limitations and use contemporary component platforms for developing applications for embedded systems. We demonstrate the approach on the SOFA 2.0 component platform. The paper shows that the only parts of the SOFA 2.0 platform, which have to be adapted, are the deployment process and the runtime environment. The rest of the platform suits for development for embedded systems without any change and allows for benefiting from SOFA 2.0 features like behavior validation, multiple communication styles, separated control part of components, etc.}, keywords={Hierarchical components, deployment, embedded environment, Java.}, pdf={deployment.pdf}, } </bibtex> <bibtex> @inproceedings{330, author={Carrig,B.;Denieffe,D.;Murphy,J.}, title={A User Controlled Priority Selection Strategy for Multiplayer Games}, booktitle={IEEE 4th Consumer Communications & Networking Conference}, year={2007}, abstract={Future Quality of Service (QoS) aware networks, such as those based on the Differentiated Services (DiffServ) architecture, will provide users with the opportunity to assign a priority to the traffic they receive and generate. Different priorities will entail different per-byte or per-packet charges. To aid users operating within such an environment, a priority selection strategy is required. In this paper, we propose a priority selection strategy based on the concept of Consumer Surplus (CS), which is the positive difference between utility or the user’s willingness-to-pay and cost. We then evaluate this strategy in a networking scenario where a user is involved in a multiplayer Counterstrike game, in which different priorities may be assigned to the downstream traffic. A utility curve, applicable to a First Person Shooter (FPS) game like Counterstrike, is presented. Using simulation results we show that for varied traffic loads, the CS strategy offers comparable application performance to that of always selecting the highest priority, but at a reduced cost to the user.}, keywords={Qos,DiffServ,Online Gaming}, pdf={user-controlled.pdf}, } </bibtex> <bibtex> @inproceedings{435, author={Z.Fratczak;Gabriel-Miro Muntean;K.Collins}, title={Electronic Monitoring of Nutritional Components}, booktitle={Information & Telecommunication Technology}, year={2007}, abstract={Obesity and other diseases related to unhealthy diet are problems of near epidemic proportion and become a growing issue every year. This paper presents a solution to this issue by proposing the use of a computer application that is able to suggest the appropriate products related to one’s diet, and to keep track of nutritional intake. The paper also describes the principle of the solution, system architecture and implementation and presents testing results. If the application’s instructions are followed by users it is expected that an optimal diet will be achieved resulting in users good health.}, keywords={Healthy diet, e-health, utility function, nutrition control}, pdf={electronic.pdf}, } </bibtex> <bibtex> @inproceedings{440, author={J.Adams;Gabriel-Miro Muntean}, title={Power Save Adaptation Algorithm for Multimedia Streaming to Mobile Devices}, booktitle={IEEE International Conference on Portable Information Devices}, year={2007}, abstract={Batteries have not followed the exponential technological improvements of other mobile device related hardware, such as CPU, memory and wireless networking. Battery power often introduces significant limitations to the use of mobile devices and their applications, including those involved in multimedia streaming that have significant high power requirements. This paper proposes a power save adaptation algorithm for mobile multimedia streaming that aims to increase streaming time given limited battery power resources. The multimedia streaming process is divided into three stages: data reception, decoding and playing and power saving solutions for each of these stages are proposed. These power save mechanisms are then combined to give the power save algorithm. Preliminary tests results show that significant increases in battery lifetime have been achieved when the power save mechanisms proposed in this paper are used.}, keywords={Algorithm,Multimedia Streaming,Mobile Devices}, pdf={power save.pdf}, } </bibtex> <bibtex> @inproceedings{441, author={E.Casey;Gabriel-Miro Muntean}, title={A Mechanism for Greediness Management whenStreaming Multimedia to Portable Devices}, booktitle={IEEE International Conference on Portable Information Devices}, year={2007}, abstract={The majority of streaming solutions use rate adaptaion based on congestion avoidance mechanisms that try to obtain as much bandwidth as possible from the limited network resources. This is good if we assume that all clients have equal requirements. However this is rarely the case as devices have unique characterstics ( e.g. screen size, screen resolution, location etc) that influence streaming related parameters & consequently the experience obtained by the end user.Due to the inherent greediness of streaming protocols & lack of knowledge about the characterstics of the users devices, this may result in certain devices receiving higher bandwidth share than they actually need & others not receiving enough,affecting the users perceived quality. Therefore there is a need to allow for client diffrentiation in order to provide an acceptable service for all cliemts,taking their device characterstics into account.This paper proposes a Greediness Control Algorithm(GCA),a specially designed application layer solution that tunes the greediness of the multimedia streaming based on client priority, to make more efficient use of the wireless network and increase the overall user perceived quality.}, keywords={Algorithm,Multimedia,Portable Devices}, pdf={mechanism.pdf}, } </bibtex> <bibtex> @inproceedings{442, author={Gabriel-Miro Muntean;N.Cranley}, title={User Quality of Experience-Aware Multimedia Streaming over Wireless Home Area Network}, booktitle={IEEE Vehicular Technology Conference}, year={2007}, abstract={For multimedia streaming over wireless networks, there is a trade-off between the capacity of the wireless links and the end-user perceived-quality, which can be affected by the compression scheme used, content characteristics and adaptation algorithm (if any). In this paper, this trade-off is investigated for streaming various motion content multimedia over an IEEE 802.11b-based Wireless-Home Area Network using the Quality-Oriented Adaptation Scheme (QOAS). QOAS performance is compared to that of a non-adaptive scheme when using MPEG-2 and MPEG-4 encoding in terms of average end-user perceived quality, number of streaming sessions concurrently supported, loss rate, delay, jitter and total throughput. Simulation results show that by using QOAS and MPEG-4 encoded streams a much higher number of concurrent streams are supported at an average quality above “good” level on the ITU-T five-point quality scale in comparison with other situations. In this case all the other streaming performance parameters were also significantly better.}, keywords={Adaptive video streaming, Wireless Home Area Network, grading scheme, end-user perceived quality.}, pdf={user quality.pdf}, } </bibtex> <bibtex> @inproceedings{443, author={J.Adams;Gabriel-Miro Muntean}, title={Adaptive Buffer Power Save Mechanism for Mobile Multimedia Streaming}, booktitle={IEEE International Conference on Communication}, year={2007}, abstract={Wireless networks are becoming a part of everyday life for many people. When a mobile device has wireless LAN capability, multimedia content can be streamed over a wireless network to that device. However, a major disadvantage of all mobile devices is their limited battery lifetime. Multimedia streaming puts extra pressure on the battery, causing it to discharge faster. In some cases, streaming tasks cannot be completed purely because the battery of the device becomes fully discharged, which causes significant user dissatisfaction. Consequently, it is necessary to devise mechanisms to enable longer battery lifetime in order to support complex applications such as those involving mobile multimedia streaming. This paper proposes an Adaptive-Buffer Power Save mechanism (AB-PSM) for increasing the battery life of mobile devices during multimedia streaming. This increase is achieved by controlling how and when data is sent over a wireless LAN. AB-PSM introduces an additional buffer which hides data from the station it is intended for, allowing it to return to sleep and consequently saving power. Data is eventually delivered in one of the station’s following attempts to receive it. Tests involving AB-PSM have been performed and show good results in terms of significant increases in battery lifetime. The comparison between AB-PSM and the IEEE 802.11 legacy power save mechanism shows important increases in battery lifetime of more than 100%.}, keywords={Wireless Network,Mobile Communications}, pdf={adaptive buffer.pdf}, } </bibtex> <bibtex> @inproceedings{444, author={T.Casey;Gabriel-Miro Muntean;D.Denieffe}, title={Influence of Mobile User Velocity on Data Transfer in a Muti-Network Wireless Environments}, booktitle={9th International Conference on Mobile & Wireless Communication Networks}, year={2007}, abstract={Heterogeneous wireless environments are now a reality in many urban areas. Designing and deploying a wireless network in such an environment is complicated by the unpredictable propagation paths of radio signals and by the unpredictable behaviour of the network users themselves. Network simulation and modelling can be used to assist in the design process. However, in order for simulation models to be effective they must be realistic. Efforts have been made to render simulation models more realistic through the analysis of real world wireless networks and through the examination and evaluation of existing simulation models. The most fundamental characteristics of a mobile user are their mobility, and the speed at which they move. The various velocities used in simulation models are unrealistic with respect to pedestrian behaviour in urban environments. In addition, the possible influence of mobile user velocity on the amount of data transferred by the user is not considered. In this paper we examine the influence of a mobile user’s velocity on throughput in a wireless network using a range of realistic velocities.}, keywords={heterogeneous wireless network environment,}, pdf={influence.pdf}, } </bibtex> <bibtex> @inproceedings{445, author={Gabriel-Miro Muntean}, title={Effect of Delivery Latency,Feedback Frequency & Network Load on Adaptive Multimedia Streaming}, booktitle={IEEE 32nd Local Computer Neworks Conference }, year={2007}, abstract={As video on demand systems gain popularity, it seems likely that the desire to serve a high number of customers from limited network resources could lead to a degradation of the endusers’ perceived quality. Quality-Oriented Adaptation Scheme (QOAS) balances the need for high quality with increased network utilization when streaming multimedia. QOAS requires client-side monitoring of some transmission-related parameters, grading of the end-user’s quality and feedback that informs the server about the received quality. In response to this feedback, the server adjusts the streaming process in order to maximize the end-user perceived quality in the current conditions. This paper studies the effect of delivery latency and feedback frequency on quality-oriented adaptive multimedia streaming. It also shows how high end-user perceived quality is maintained in the presence of different types of background traffic while recording a significant increase in link utilization and a very low loss rate.}, keywords={Adaptive video streaming, grading scheme, end-user}, pdf={effect of delivery.pdf}, } </bibtex> <bibtex> @inproceedings{452, author={Gabriel-Miro Muntean;N.Cranley}, title={Resource Efficient Quality-Oriented Wireless Broadcasting of Adaptive Multimedia Content}, booktitle={IEEE Trans. on Broadcasting}, year={2007}, abstract={The performance of multimedia stream delivery is influenced by encoding scheme, streaming solution and network conditions. This paper studies the performance of multimedia streaming when using the Quality-Oriented Adaptive Scheme (QOAS) over an IEEE 802.11b Wireless LAN and compares it to that achieved when using other solutions that do not consider end-user quality in their delivery process such as TFRC, LDA+, and non-adaptive schemes. The performance is assessed in terms of average end-user perceived quality, number of concurrent streaming sessions, loss rate, delay, jitter and total throughput when streaming MPEG-4 encoded content. Simulation results show that the QOAS out-performs these other streaming solutions in all aspects of network delivery. QOAS can support a greater number of concurrent streaming sessions at a higher average quality. In addition, for the same number of clients QOAS achieved a higher average end-user quality, as well as better network delivery streaming performance parameters.}, keywords={Adaptive multimedia streaming, end-user quality}, pdf={rsource.pdf}, } </bibtex> <bibtex> @inproceedings{170, author={C. Thorpe; S. Murphy; L. Murphy}, title={Seamless Handover in Heterogeneous Radio Access Networks}, booktitle={IT&T}, year={2006}, abstract={This paper provides a detailed discussion of the problem of Seamless Handover in Heterogeneous Radio Access Networks. Brief descriptions of several wireless access technologies are included to provide some background information and to illustrate the importance of solving the seamless handover problem for network subscribers. Several approaches to providing a handover solution have been proposed, some of which will be described and compared, in order to indicate possible directions for continuing to search for a seamless handover solution. Various problems are present in the existing solutions, and are discussed in this paper. These problems are significant enough to warrant further investigation in the handover area, and leave scope for modifications and improvements.}, keywords={Seamless Handover, Heterogenous Networks, SCTP}, pdf={christina-itt06-cameraReady.pdf}, } </bibtex> <bibtex> @inproceedings{161, author={C. Thorpe; L. Murphy}, title={A Survey of Seamless Handover in Heterogeneous Radio Access Networks}, booktitle={ACM/IEEE International Symposium on Modeling, Analysis and Simulation of Wireless and Mobile Systems}, year={2006}, abstract={This paper provides a detailed discussion of the problem of Seamless Handover in Heterogeneous Radio Access Networks. Several approaches to providing a handover solution have been proposed, some of which will be described and compared, in order to indicate possible directions for continuing to search for a seamless handover solution. Various problems are present in the existing solutions, and are discussed in this paper. }, keywords={Seamless Handover, Heterogenous Networks, SCTP}, pdf={Christina-MSWIM-Oct-2006.pdf}, } </bibtex> <bibtex> @inproceedings{213, author={J. Fitzpatrick, S. Murphy and J. Murphy}, title={An Approach to Transport Layer Handover of VoIP over WLAN}, booktitle={CCNC}, year={2006}, abstract={In this paper a transport layer handover mechanism for Voice over Internet Protocol (VoIP) using the Stream Control Transmission Protocol (SCTP) is proposed. This handover mechanism utilizes the multi-homing feature of SCTP to allow connection to multiple wireless networks. Each available wireless network is probed with simulated VoIP data to obtain network performance metrics. Handover decisions are made based on the Mean Opinion Score (MOS) calculated from the ITU-T E-Model for voice quality assessment using the obtained measurements. Implementation and simulations were carried out using the NS2 network simulator. The results show the MOS obtained using the proposed handover mechanism on IEEE 802.11b WLAN access points (APs) under varying load conditions. High correlation is shown between the MOS from the proposed handover scheme and the MOS experienced by a VoIP node present in the network. A simulation showing an SCTP endpoint handover between AP’s is presented.}, keywords={SCTP, E-Model, VoIP, Handover, Heterogeneous Networks}, } </bibtex> <bibtex> @inproceedings{215, author={J. Fitzpatrick, S. Murphy, J. Murphy}, title={RTS/CTS Based Endpoint Admission Control for VoIP Over 802.11e}, booktitle={MMNS}, year={2006}, abstract={In this paper an endpoint-based admission control mechanism for VoIP over WLAN is proposed. The mechanism operates by first measuring the utilisation of the channel and comparing this to a pre-determined threshold, if the channel utilisation exceeds this threshold, the call is rejected. One important aspect of the mechanism is that it can operate in the presence of hidden terminals. This is done by using the Request-to-Send/Clear-to-Send WLAN signalling to determine channel utilisation. The scheme is designed to be flexible; it can operate with heterogeneous data rates, with varying traffic types and in the presence of legacy 802.11 nodes. The scheme was developed and evaluated using the Qualnet network simulator. An empirical approach was used to determine appropriate admission thresholds. Then, simulations were performed to demonstrate the successful operation of the scheme.}, keywords={Call Admission Control, VoIP, 802.11e, RTS/CTS}, } </bibtex> <bibtex> @inproceedings{311, author={Carrig,B.;Denieffe,D.;Murphy,J.}, title={A Relative Delay Minimization Scheme for Multiplayer Gaming in Diffrentiated Services Network}, booktitle={ACM SIGCOMM Workshop on Network & System Support for Games}, year={2006}, abstract={Multiplayer gaming over the Internet continues to grow in popularity, despite a lack of Quality of Service (QoS) mechanisms. Future QoS-aware networks such as those based on the Differentiated Services (DiffServ) framework will provide an opportunity for gamers to enhance their game-playing experience. An important QoS metric for networked games is a user’s delay relative to the delay of other users. In this paper, we propose a Relative Delay Minimization (RDM) algorithm for use in DiffServ environments. Simulation results are described and presented showing that the algorithm can reduce the Relative Delay Variation (RDV) between users in a DiffServ environment.}, keywords={Network Games, Relative Delay, DiffServ, QoS}, pdf={a relative delay.pdf}, } </bibtex> <bibtex> @inproceedings{312, author={Noonan,J.;Perry,P.;Murphy,J.}, title={End-point Synchronisation & Handover For Multi-homed Services}, booktitle={IEE Proceedings-Communications}, year={2006}, abstract={It is proposed to implement a synchronised routing table at the transport layer, referred to as an Association Routing Table (ART), to improve the performance of multi-homed transport protocols. An algorithm is described that ensures that the routing tables can be synchronised, which is then used to implement a handover mechanism. The ART is implemented within SCTP. It is shown that by using a synchronised ART, it is possible to implement failover in cases where standard SCTP cannot, con¯gurations are more resilient to network errors, and it is possible to perform a handover without any network support.}, keywords={Multi-homing, routing, transport layer, SCTP, handovers}, pdf={end point-sychronization.pdf}, } </bibtex> <bibtex> @inproceedings{313, author={Hillestad,O.I.;Perkis,A.;Genc,V.;Murphy,S.;Murphy,J.}, title={Delivery of On-Demand Video Services in Rural Areas via IEEE 802.16 Broadband Wireless Access Networks}, booktitle={ACM 2nd Workshop on Wireless Multimedia Networking & Performance Modelling }, year={2006}, abstract={A simulation study of delivery of streaming video on-demand via IEEE 802.16 based technologies is described. A number of scenarios are simulated which are representative of rural area deployments of such technologies. The study finds that IEEE 802.16 can support up to 9/10 simultaneous users streaming typical cinematic video content in CIF resolution, 24 frames/s, at average rates of around 750 kbps. Further, the study demonstrates the utility of H.264/AVC Scalable Video Coding (SVC) and a buffer-based congestion control algorithm in an adaptive video streaming solution.}, keywords={IEEE 802.16, video streaming, scalable video coding}, pdf={delivering of on demand.pdf}, } </bibtex> <bibtex> @inproceedings{314, author={Ormond,O.;Muntean,G.;Murphy,J.}, title={Evaluation of an Intelligent Utility-Based Strategy for Dynamic Wireless Network Selection}, booktitle={Autonomic Management of Mobile Multimedia Services}, year={2006}, abstract={In the case of next generation wireless networks, different users with various multi-homed personal wireless devices will aim to exploit the full potential of the choice of services and applications available over different radio access networks. In their selection of a certain radio access network consumers will consider money and delay preferences for the current application and will rely on intelligent network-selection decision strategies to aid them in their choice. This paper describes the evaluation of an intelligent utility-based strategy for network selection in a multi-access network situation for transfer of large non real-time data files. A number of scenarios are examined which compare the proposed network selection strategy against other possible strategies. Test results show how by using this network selection strategy significant benefits in terms of combined average delay and cost per file transferred as well as transfer efficiency are obtained.}, keywords={Heterogeneous Wireless Networks, Multi-homed Radio Terminals, User-centric Network Selection.}, pdf={evaluation.pdf}, } </bibtex> <bibtex> @inproceedings{315, author={Parsons,T.;Mos,A.;Murphy,J.}, title={Non-Intrusive End to End Run-time Path Tracing for J2EE Systems}, booktitle={IEE Proceedings-Software}, year={2006}, abstract={An end-to-end runtime path-tracing approach for J2EE systems has been introduced. The approach is non-intrusive and thus does not require instrumentation of middleware or application source code. The implementation of the system has been realised in the COMPAS Java end-to-end monitoring tool that extends and integrates a number of open source projects. The first set of results shows the performance overhead associated with the tool. Further results show the portability of this approach, by applying it to a number of different application server implementations. Finally, it is also shown that runtime paths collected by the implementation can be used for reasoning about the overall system structure and design of complex enterprise applications.}, keywords={IEEE ,Server}, pdf={non-intrusive.pdf}, } </bibtex>