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  • 651.
    Schmidt, Mischa
    et al.
    NEC Europe Laboratories.
    Abbadessa, Daniele
    NEC Europe Laboratories.
    Felis, Sebastian
    NEC Europe Laboratories.
    Enriching IMS based IPTV with Virtual Identity Management: Experiences2007Conference paper (Other academic)
  • 652.
    Baraër, Christophe
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    Phanse, Kaustubh
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    Nykvist, Johan
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    Birsa, Luka
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    ExPLoIT: exploiting past location information and transitivity for positioning in mobile sensor networks2007In: 2nd International Conference on Communication Systems Software and Middleware, 2007: COMSWARE 2007 ; 7 - 12 Jan. 2007, Bangalore, India, Piscataway, NJ: IEEE Communications Society, 2007Conference paper (Refereed)
    Abstract [en]

    We present a novel distributed range-free technique called ExPLoIT for estimating geographical location of sensor nodes in mobile sensor networks. ExPLoIT is the first positioning technique that exploits location information at regular nodes in addition to using seeds. The key idea is the notion of confidence that a node has in its location estimate which can be used by other nodes for localization. Using Monte Carlo integration, a node estimates its current location and confidence based on its past location and the location information it receives from its neighbors. Node mobility is exploited to transitively localize the network. Our extensive simulation study shows that our proposal outperforms three other state-of-the-art range-free localization techniques under a wide range of conditions. The strength of ExPLoIT is that it is robust to irregular radio propagation, arbitrary seed and node density, and stochastic seed and node mobility; no special hardware is necessary at sensor nodes.

  • 653.
    Nugent, Chris
    et al.
    University of Ulster.
    Davies, Richard
    University of Ulster.
    Hallberg, Josef
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Donnelly, Mark
    University of Ulster.
    Synnes, Kåre
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    Poland, Michael
    University of Ulster.
    Wallace, Jonathan
    University of Ulster.
    Finlay, Dewar
    University of Ulster.
    Mulvenna, Maurice
    University of Ulster.
    Craig, David
    Belfast City Hospital/Queen’s University of Belfast.
    HomeCI - a visual editor for healthcare professionals in the design of home based care2007In: 2007 annual international conference of the IEEE Engineering in Medicine and Biology Society: [EMBC '07] ; Lyon, France, 22 - 26 August 2007, IEEE Communications Society, 2007, p. 2787-2790Conference paper (Refereed)
    Abstract [en]

    The demands of introducing more practical means of managing and monitoring technology within the home environment to support independent living are increasing. Within this paper we present a prototype solution referred to as HomeCI which allows healthcare professionals to establish the conditions within which technology in the home should operate. The HomeCI concept is based on the use of visual notation and has been designed for use by persons with a non technical background. Within the paper we present the design of the first version of the HomeCI visual editor and present the results of a usability study conducted on 4 healthcare professionals.

  • 654.
    Nugent, Chris
    et al.
    University of Ulster.
    Finlay, Dewar
    University of Ulster.
    Davies, Richard
    University of Ulster.
    Wang, Hui
    University of Ulster.
    Zheng, Huiru
    University of Ulster.
    Hallberg, Josef
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Synnes, Kåre
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    Mulvenna, Maurice
    University of Ulster.
    homeML - an open standard for the exchange of data within smart environments2007In: Pervasive Computing for Quality of Life Enhancement: 5th International Conference on Smart Homes and Health Telematics, ICOST 2007, Nara, Japan, June 21 - 23, 2007 ; proceedings / [ed] Takeshi Okadome; Tatsuya Yamazaki; Mounir Makhtari, Berlin: Encyclopedia of Global Archaeology/Springer Verlag, 2007, p. 121-129Conference paper (Refereed)
    Abstract [en]

    This work describes a potential solution to the problems caused by the heterogeneous nature of the data which may be collected within smart home environments. Such information may be generated at an intra- or interinstitutional level following laboratory testing or based on in-situ evaluations. We offer a solution to this problem in the form of a system/application/format independent means of storing such data. This approach will inevitably support the exchange of data within the research community and form the basis of the establishment of an openly accessible data repository. Within this abstract we present the outline design of homeML, an XML based schema for representation of information within smart homes and through exemplars demonstrate the potential of such an approach. An example of the typical type of software browser required for the data representation is also presented.

  • 655.
    Schmidt, Mischa
    et al.
    NEC Laboratories Europe, NEC Europe Ltd., Heidelberg.
    Wilde, Andreas
    NEC Europe Ltd..
    Schülke, Anett
    NEC Europe Ltd..
    Costa, Henrique
    NEC Portugal.
    IMS interoperability and conformance aspects [IP Multimedia Systems (IMS) Infrastructure and Services]2007In: IEEE Communications Magazine, ISSN 0163-6804, E-ISSN 1558-1896, Vol. 45, no 3, p. 138-142Article in journal (Refereed)
    Abstract [en]

    In this article, we take a closer look at interoperability and conformance aspects when using 3GPP IMS, ETSI TISPAN NGN, and related OMA service enablers. Considering the increasingly important role of 3GPP IMS within mobile and NGN (next generation network) contexts, we highlight the importance of interoperability and conformance testing of IMS products

  • 656.
    Andersson, Karl
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    Granlund, Daniel
    Åhlund, Christer
    M4: MultiMedia Mobility Manager: a seamless mobility management architecture supporting multimedia applications2007In: Proceedings of the 6th International Conference on Mobile and Ubiquitous Multimedia: December 12 - 14, 2007, Oulu, Finland / [ed] Timo Ojala, Red Hook, NY: Curran Associates, Inc., 2007, p. 6-13Conference paper (Refereed)
    Abstract [en]

    In this paper, a proof-of-concept and a software architecture, M4 (MultiMedia Mobility Manager), is presented. In short, M4 is offering seamless mobility management to multimedia appli­cations using a variety of wireless access networks. First, M4 is built on multihomed Mobile IP building on the principle of soft handovers. Second, network selection in M4 is based on a network layer metric combining round-trip times and jitter in round-trip times. Third, the end-user can enter its own preferences on network selection through a policy-based extension to the proposed network selection algorithm.The proposed architecture is evaluated in a live heterogeneous networking environment where handover performance is studied in detail. In addition, user-perceived quality of experience for Voice over IP using the M4 software architecture has been studied. Last, downloads of large amount of data using a combination of high and low capacity wireless networks in M4 were studied.Results indicate that the architecture as a whole and the proposed algorithms perform well. M4 can thus be seen as an imple­mentation of the "Always Best Connected" vision.

  • 657.
    Brännström, Robert
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    Mobility management in heterogeneous access networks2007Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis proposes, describes and validates solutions to enhance mobility in heterogeneous access networks. Wireless access networks have become available almost everywhere and current research strives to make them pervasive. Users having wireless access to the Internet are driving the demand for mobile and heterogeneous solutions where services could be accessed from anywhere, any time and from any device. Future wireless connectivity will be provided through a mix of coexisting heterogeneous access network technologies. To enhance mobility in heterogeneous networks this thesis focuses on mobility management systems and connectivity of wireless multi-hop ad hoc networks to the Internet. In a wireless environment with overlapping service areas, mobile nodes need to select which gateway(s) to use to access the wireless infrastructure. The metrics used to select the point of attachment within an access technology are insufficient to compare the capacity of different technologies or multi-hop routes. This thesis proposes, describes and validates solutions to calculating network layer metrics and using them in gateway selection and handover decisions. To enable connectivity of a mobile ad hoc network (MANET) to the Internet, a gateway must bridge the wired single-hop and wireless multi-hop approaches. A MANET enables connectivity to more than one gateway at a time and combined with multihoming it provides seamless handover between subnets. The gateway selection and handover decisions are complicated by the multihoming capabilities. Connectivity to Internet services makes it important to maintain the efficient route to the gateway. It is also important to identify the location of a destination to separate the management of Internet and intra MANET destinations. This thesis proposes,describes and validates solutions to deploying multihomed mobility into MANETs and thereby handling multi-hop gateway discovery, registration of multiple gateways and tunneling to selected gateway(s). The solution maintains gateway connectivity in MANETs by installing routes to gateways using advertisements and manages route discovery based on the destination locality. Both applications with mobility awareness (e.g. SIP phones) and those without it must be supported by a mobility management system. The existence of network layer mobility management can enhance an application layer system. This thesis proposes, describes and validates deployment of a mobility management system with support of both application and network layer mobility. With wireless access networks some technologies might not support some types of applications and a single technology might not cope with all the application demands from a mobile node. Thus the control of individual traffic flows could be used to share the load on multiple access technologies and to direct flows over specified technologies. This thesis proposes, describes and validates solutions to identification and mobility management of individual traffic flows in a heterogeneous network environment. Finally this thesis proposes, describes and validates a deployment proposal of route evaluation and flow control to enable load balancing in wireless multi-hop networks.

  • 658.
    Andersson, Karl
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    Sarker, ANM. Zaheduzzaman
    Luleå University of Technology.
    Åhlund, Christer
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    Multihomed mobile IPv6: OPNET simulation of network selection and handover timing in heterogeneous networking environments2007In: Proceedings of the Eleventh Annual OPNET Technology Conference: OPNETWORK 2007, 2007Conference paper (Refereed)
  • 659.
    Brännström, Robert
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    Åhlund, Christer
    Andersson, Karl
    Granlund, Daniel
    Multimedia flow mobility in heterogeneous networks using multihomed mobile IP2007In: Journal of Mobile Multimedia, ISSN 1550-4646, E-ISSN 1550-4654, Vol. 3, no 3, p. 218-234Article in journal (Refereed)
    Abstract [en]

    Communication in next generation networks will use multiple access technologies, creating a heterogeneous network environment. To enable end-user terminals to move between access networks with minimal disruption, the terminals should be able to maintain multiple active network connections. Such a multihomed mobile host will experience differences in capabilities and coverage area depending on the access technologies. This paper proposes and evaluates an extension to Mobile IP enabling multihoming, regardless of the access technology. Mobility of multimedia communication in this environment should adapt to changing conditions and be based on dynamic measurements and user preferences. The proposed architecture gives opportunities for mobile multimedia applications to use multiple access networks simultaneously and the possibility to move individual flows between access networks and between user devices. Media flows are identified by destination IP address, protocol and port number. Evaluation results are presented both from a simulation study and from a real world prototype implementation using three different wireless access technologies: 802.11, UMTS and 802.16-2004.

  • 660.
    Wallin, Stefan
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    Leijon, Viktor
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Multipurpose models for QoS monitoring2007In: 21st International Conference on Advanced Information Networking and Applications Workshops: Niagara Falls, Ontario, Canada, 21 - 23 May 2007 ; proceedings, Los Alamitos, Calif: IEEE Communications Society, 2007, Vol. 1, p. 900-905Conference paper (Refereed)
    Abstract [en]

    Telecom operators face an increasing need for service quality management to cope with competition and complex service portfolios in the mobile sector. Improvements in this area can lead to significant market benefits for operators in highly competitive markets. We propose an architecture for a service monitoring tool, including a time aware formal language for model specification. Using these models allows for increased predictability and flexibility in a constantly changing environment.

  • 661.
    Brännström, Robert
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    Åhlund, Christer
    Zaslavsky, Arkady
    Port-based multihomed mobile IPv6: load-balancing in mobile ad hoc networks2007In: Proceedings: the 31st IEEE Conference on Local Computer Networks, LCN 2006 : Tampa, Florida, U.S.A., November 14 - 16, 2006, Piscataway, NJ: IEEE Communications Society, 2007, p. 269-271Conference paper (Refereed)
    Abstract [en]

    With today's heterogeneous access to the Internet, users will move between wired and wireless environments and between infrastructure mode and ad hoc mode of wireless communication. When a mobile node moves from an infrastructure connection and connects multihop to an Internet gateway, the performance will degrade and it may not be able to send all of its traffic via a single gateway. This highlights the need of load-balancing between Internet gateways, especially since the behavior of users today involves a multitude of parallel activities generating multiple flows. This paper proposes a solution that enables distribution of individual traffic flows via different Internet gateways instead of using one single gateway. The proposal includes extensions to Mobile IP in order to handle flow mobility bindings. The performance of the solution is verified by simulation studies.

  • 662.
    Andersson, Karl
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    Åhlund, Christer
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    Projekt: Hybrinet@Skellefteå2007Other (Other (popular science, discussion, etc.))
    Abstract [sv]

    Projektet Hybrinet@Skellefteå studerar effektiv multimediedistribution i heterogena nätverksmijöer

  • 663.
    Jayaraman, Prem Prakash
    et al.
    Monash University, Melbourne, VIC.
    Zaslavsky, Arkady
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    Delsing, Jerker
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Sensor data collection using heterogeneous mobile devices2007In: 2007 IEEE International Conference on Pervasive Services: [ICPS '07] ; Istanbul, Turkey, 15 - 20 July 2007, Piscataway, NJ: IEEE Communications Society, 2007, p. 161-164Conference paper (Refereed)
    Abstract [en]

    Data collection has always been a major challenge in sensor networks and various techniques have been proposed to enable efficient data collection. One such methodology is the use of mobile elements within the existing infrastructure to enable data collection. The paper proposes the use of existing mobile elements like mobile phones which have enough spare capacity to act as data carriers within a sensor network to carry sensor data. With advent of technology, mobile devices have become so powerful that they can work in a pervasive environment and make decisions based on context information like presence, location etc. Our proposal is an intelligent heterogeneous network in which the sensor nodes act as the data accumulators and the context-aware mobile phones act as data carriers of the sensed data. A framework that enables the mobile node and sensor node communication over Bluetooth is proposed and a p implementation is presented.

  • 664.
    Scholl, Jeremiah
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science. Norwegian Centre for Telemedicine.
    McCarthy, John
    University College London.
    Harr, Rikard
    Umeå universitet.
    A comparison of chat and audio in media rich environments2006In: Computer Supported Cooperative Work: Proceedings of the 2006 20th anniversary conference on Computer supported cooperative work, IEEE Communications Society, 2006, p. 323-332Conference paper (Refereed)
    Abstract [en]

    This paper presents two case studies of informal group communication using multimedia conferencing that supports various media including video, audio and chat. The studies provide a comparison of audio and chat as communication medium and present data on usage patterns, user preferences and attitudes. The quantitative and qualitative data collected suggest that chat does have advantages in some situations when used for informal communication along with video. The results provide evidence against the hypothesis that chat is a low bandwidth alternative only used when audio communication is unavailable. This suggests that video mediated chat deserves further attention from designers and the research community, since it is often ignored as a "useful" scenario.

  • 665. Kristiansson, Johan
    et al.
    Parnes, Peter
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    An application-layer approach to seamless mobile multimedia communication2006In: IEEE Transactions on Network and Service Management, ISSN 1932-4537, E-ISSN 1932-4537, Vol. 3, no 1, p. 33-42Article in journal (Refereed)
    Abstract [en]

    Providing seamless IP mobility support is one of the most challenging problems towards a world of mobile and ubiquitous multimedia communication. This paper proposes an application-layer framework based on the Session Initiation Protocol and the Resilient Mobile Socket to provide mobility support for distributed multimedia applications. As a part of the framework the paper describes a new handover strategy called Competition-based Soft-Handover Management that uses simulcast to improve quality of service and to seamlessly hand over multimedia traffic to the network interface that currently offers better network characteristics. In short, during a handover packets are simulcasted through all available network interfaces, and when the packets are received by the remote end-point, they are merged back into one stream. As each network connection competes with other connections in contributing to the merged stream at the remote end-point, the handover process can be viewed as a competition where the connection that contributes most is selected after the handover. As a proof of concept, the framework has been integrated into Marratech, which is a commercially available audio/video group communication application. By using network emulators, the paper demonstrates how the framework can be used to improve QoS, compare end-to-end performance, and perform lossless handovers while reducing redundant packets.

  • 666.
    Andersson, Karl
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    Åhlund, Christer
    An architecture for seamless mobility management in various types of applications using a combination of MIP and SIP2006In: Proceedings of Swedish National Computer Networking Workshop 2006: sponsored by IEEE VT/COM Sweden : October 26-27, 2006, Luleå University of Technology, Luleå: Luleå tekniska universitet, 2006, p. 33-36Conference paper (Refereed)
    Abstract [en]

    In the future, mobile users will have the possibility to use a variety of wireless access networks simultaneously making the vision "Always best connected" come true. The Internet Protocol (IP) will most likely be the least common divisor allowing service providers to deploy services in a unified way regardless of access network type (being wired or wireless). The 3GPP-led development of the IP Multimedia Subsystem (IMS) is a promising step towards the vision. However, there are a number of obstacles along this way forward. Various deployment difficulties related to already installed base of user and infrastructure equipment and service providers protecting their old investments are the most common obstacles. In addition to those reasons, somewhat conservative regulatory authorities, short-comings in digital rights management, multiple standardization bodies proposing non-aligned solutions, as well as non-uniformed and non-optimized use of radio spectrum do not improve the speed of change.Our research is performed within the area of seamless real-time multimedia distribution in heterogeneous wireless access networks with a user-centric and end-to-end system approach. Having proposed various extensions to Mobile IP (MIP) including multihoming and port-based handling of flows, as well as solutions for global connectivity in ad hoc networks we now present a combined architecture using both MIP and Session Initiation Protocol (SIP) for mobility management where MIP is used for TCP connections and SIP is used for UDP traffic carrying real-time multimedia streams of data.

  • 667. Kodikara, E. Ruwini
    et al.
    Brännström, Robert
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    Åhlund, Christer
    Zaslavsky, Arkady
    APM: Adaptive Performance Metric2006Conference paper (Other academic)
  • 668.
    Kodikara, R.E
    et al.
    Caulfield School of Information Technology, Monash University.
    Zaslavsky, Arkady
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    Åhlund, Christer
    ConEx: context exchange in MANETs for real time multimedia2006In: International Conference on Networking: ICN 2006 ; Morne, Mauritius, 23 - 28 April, 2006 ; bonus: International Conference on Mobile Communications and Learning Technologies (MCL 2006), International Conference on Systems (ICONS 2006) ; proceedings / [ed] Pascal Lorenz, Los Alamitos, Calif: IEEE Computer Society Press , 2006, p. 70-Conference paper (Refereed)
    Abstract [en]

    MANETs are important and integral part of next generation wireless networking. Real time multimedia communication over MANETs is challenging due to reasons like network topology changes, limitations of wireless links and demanding requirements of multimedia. Channel adaptivity is adopting applications to the dynamic and unpredictable network conditions. QoS adaptivity is adopting lower layers to multimedia application requirements. The novel cross layer context exchange approach called ConEx, presented in this paper improves the efficiency of this two-way information exchange. This paper focuses on adaptive multimedia applications over mobile ad hoc networks, which addresses the challenges of multimedia applications. ConEx uses publish-subscribe event notification system for vertical context exchange across layers of the mobile host and horizontal context exchange across the MANET. ConEx architecture and implementation issues are discussed in this paper.

  • 669.
    Svensson, Sara
    et al.
    Luleå tekniska universitet.
    Hallberg, Josef
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Lindgren, Per
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Östmark, Åke
    Delsing, Jerker
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Synnes, Kåre
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    Cross-country skiers go on-line2006Report (Other academic)
    Abstract [en]

    This article presents a pervasive computing system which give spectators of sport events an enriched media experience. The system utilizes Internet- enabled sensor technology integrated into a context-aware platform and was evaluated during real-life use at the Vasaloppet cross-country ski event. Sensor data was transmitted from contestants, using Bluetooth wireless ad- hoc networking and GPRS technology, to the context-aware platform which in turn presented the sport event spectator with a personalized and context- aware view. The system architecture and integration of components are discussed in this article, together with evaluations from technical and user perspectives. The results confirm that our approach is technically feasible and that the system provides an enriched media-experience for the majority of spectators.

  • 670.
    Bodin, Ulf
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    Schelén, Olov
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    Vemmervik, Claes
    Operax AB.
    End-to-End QoS control architectures from a wholesale and retail perspective: benefits and challenges2006Conference paper (Refereed)
  • 671.
    Lindgren, Anders
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    Phanse, Kaustubh
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    Evaluation of queueing policies and forwarding strategies for routing in intermittently connected networks2006In: The 1st International Conference on Communication System Software and Middleware: COMSWARE 2006 : January 8-12, 2006, Delhi, India, Piscataway, N.J.: IEEE Communications Society, 2006, p. 1-10Conference paper (Refereed)
    Abstract [en]

    Delay tolerant networking (DTN) and more specifically the subset known as intermittently connected networking, is emerging as a solution for supporting asynchronous data transfers in challenging environments where a fully connected end-to-end path between a source and destination may never exist. Message delivery in such networks is enabled via scheduled or opportunistic communication based on transitive local connectivity among nodes influenced by factors such as node mobility. Given the inherently store-and-forward and opportunistic nature of the DTN architecture, the choice of buffer management policies and message forwarding strategies can have a major impact on system performance. In this paper, we propose and evaluate different combinations of queueing policies and forwarding strategies for intermittently connected networks. We show that a probabilistic routing approach along with the correct choice of buffer management policy and forwarding strategy can result in much performance improvements in terms of message delivery, overhead and end-to-end delay.

  • 672.
    Drugge, Mikael
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    Witt, Hendrik
    TZI, Wearable Computing Lab, University of Bremen.
    HotWire: an apparatus for simulating primary tasks in wearable computing2006In: CHI '06 extended abstracts on Human factors in computing systems, New York: ACM Digital Library, 2006, p. 1535-1540Conference paper (Refereed)
    Abstract [en]

    In this paper we present a novel apparatus for simulating real world primary tasks typically found in wearable computing. Additionally, we report on a preliminary interruption study using the new apparatus in a laboratory experiment and compare its results with previous work to show its applicability for research in human-computer interaction for wearable computers.

  • 673.
    Brännström, Robert
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    Åhlund, Christer
    Kodikara, E. Ruwini
    Zaslavsky, Arkady
    Implementing global connectivity and mobility support in a wireless multi-hop ad hoc network2006In: Proceedings of the 4th Asian International Mobile Computing Conference: AMOC 2006, 2006, article id 100-063Conference paper (Refereed)
    Abstract [en]

    Pervasive access to the Internet is driven by users who want wireless connectivity to ad hoc as well as infrastructure networks. Multi-hop wireless connectivity widens the coverage areas of access networks and enables two-way wireless traffic into previously dead-spot areas. This paper addresses network mobility issues, which are essential for roaming users who connect to the Internet through wireless access networks. We propose to support connectivity to wired infrastructure through multiple gateways with possibly different capabilities and utilization. Increased network performance can be achieved by adapting to variations in performance and coverage and by switching between gateways when beneficial. We present an efficient solution to enable ad hoc access to the Internet as well as interoperation of reactive routing protocols with Mobile IP. Our solution combines the benefits of proactive agent advertisement and reactive route discovery into a flexible multi-hop access network. We also discuss wireless network metrics that can be used for more intelligent decision making on gateway selection. The feasibility of our approach is validated by simulation and implementation.

  • 674.
    Drugge, Mikael
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    Interaction aspects of wearable computing for human communication2006Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis presents the use of wearable computers for aiding human communication over a distance, focusing on interaction aspects that need to be resolved in order to realize this goal. As wearable computers by definition are highly mobile, always on, and always accessible, the ability to communicate becomes independent of place, time and situation. This also imposes new requirements on the user interface of the wearable computer, calling for natural and unobtrusive interaction with the user.One of the key challenges in wearable computing today is to streamline the user’s interaction, so that it is tailored for the situation at hand. A user interface that takes too much effort to use, interrupts or requires more than a minimum of attention, will inevitably hamper the user’s ability to perform tasks in real life. At the same time, human communication involves both effort, interruptions and paying attention, so the key is to find a balance where wearable computers can aid human communication without being intrusive. To design user interfaces supporting this, we need to know what roles different aspects of interaction have in the field of wearable computing. In this thesis, the use of wearable computing for aiding human communication is explored around three aspects of interaction.The first aspect deals with how information can be conveyed by the wearable computer user, allowing a user to retrieve advice and guidance from experts, and remote persons to share experiences over a distance. The thesis presents findings of using wearable computing for sharing knowledge and experience, both for informal exchange among work colleagues, as well as enabling more efficient communication among health-care personnel. The second aspect is based on findings from these trials and concerns how the wearable computer interacts with the user. As the user performs tasks in the real world, it is important to determine how different methods of notifying the user affects her attention and performance, in order to design interfaces that are efficient yet pleasant to use. The thesis presents user studies examining the impact of different methods of interruption, and provides guidelines for how to make notifications less intrusive. The third and final aspect considers how the user’s physical interaction with the wearable computer can be improved. The thesis presents rapid prototyping of systems employing user centric design. Furthermore, a framework for ubiquitousmultimedia communication is presented, enabling wearable computers to be dynamically configurable and utilize resources in the environment to supplement the user’s equipment.All in all, the thesis presents how wearable communications systems can be developed and deployed, how their human-computer interaction should be designed for unobtrusive operation, and how they can come to practical use in real world situations.

  • 675.
    Brännström, Robert
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    E, Ruwini Kodikara
    Monash University, Melbourne, VIC.
    Åhlund, Christer
    Zaslavsky, Arkady
    Mobility management for multiple diverse applications in heterogeneous wireless networks2006In: New technologies for consumer networking and communications: eliminating boundaries: 2006 3rd IEEE Consumer Communications and Networking Conference ; CCNC 2006 ; Harrah's Las Vegas Casino & Hotel, Las Vegas, Nevada, USA, 8 - 10 January 2006, Piscataway, NJ: IEEE Communications Society, 2006, p. 818-822Conference paper (Refereed)
    Abstract [en]

    This paper presents a mobility management solution to support both applications who are mobility-aware and those who are not. Mobility management in heterogeneous network environments needs to address the double meaning of the IP address as an endpoint identifier and a location identifier. Application-layer mobility use a non-IP endpoint identifier (e.g. user @ realm) while network-layer mobility uses a fixed home IPaddress as endpoint identifier. The resolving of the endpoint identifier to a temporary unicast IP address as location identifier needs support from a mobility management system. This paper proposes a mobility support system that integrates the benefits of application-layer SIP mobility with network-layer MIP mobility. A cross-layer information system provides context for mobility adaptation. Context awareness enhances handover decisions, transport performance and media adoption. The network-layer mobility supports the application to locate the destination ondemand for the initial setup of the sessions. The paper includes an initial evaluation of the network-layer mobility part of the solution.

  • 676.
    Phanse, Kaustubh
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    Bhat, Aniket
    Computer Networks and Software Inc., Springfield.
    Silva, Luiz A. Da
    Virginia Polytechnic Institute and State University.
    Modeling and evaluation of a policy provisioning architecture for mobile ad-hoc networks2006In: Journal of Network and Systems Management, ISSN 1064-7570, E-ISSN 1573-7705, Vol. 14, no 2, p. 261-278Article in journal (Refereed)
    Abstract [en]

    The ability to dynamically configure mobile ad-hoc network (MANET) devices is critical for supporting complex services such as quality of service (QoS), security and access control in these networks. In our work, we address the problem of policy distribution and provisioning in MANETs. Previously, we have proposed a policy provisioning architecture that enables the operator, e.g., a military command and control center, to maintain a logically centralized control of the network as a whole, while allowing a physically decentralized and self-managing implementation essential for a MANET environment. In this paper, we present an analytical model of the availability of the policy distribution service in a MANET and analyze the performance using stochastic Petri nets (SPNs). We develop the model at two levels of complexity: as a simple Markovian model with Poisson assumptions and as a more accurate non-Markovian model with general distributions obtained using statistical parameterization. We compare and cross-validate the analytical results with simulation and experimental results. Finally, we illustrate the effectiveness of the architecture for managing QoS for soft real-time applications, using an emulated mobile ad-hoc network testbed.

  • 677.
    Nykvist, Johan
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Phanse, Kaustubh
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    Modeling connectivity in mobile ad-hoc network environments2006In: Proceedings, 6th Scandinavian Workshop on Wireless Ad-hoc Networks (ADHOC'06), Stockholm: Wireless at KTH, Royal institute of technology , 2006Conference paper (Refereed)
    Abstract [en]

    Spatial mobility models are commonly used to evaluate protocol performance in mobile ad-hoc networks. Choosing parameters for such models so that they correspond to the target environments is not trivial. In this paper, we present a temporal connection model that we believe is better suited for the task. We analyze traces from real world adhoc networks in order to create models that correspond to the topological and temporal properties of these networks.

  • 678.
    Åhlund, Christer
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    Brännström, Robert
    Andersson, Karl
    Tjernström, Örjan
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    Multimedia flow mobility in heterogeneous networks using multihomed mobile IPv62006In: Proceedings of the 4th International Conference on Advances in Mobile Computing and Multimedia: MoMM 2006, 2006Conference paper (Refereed)
    Abstract [en]

    Communication in next generation networks will use multiple access technologies, creating a heterogeneous network environment. To enable end-user terminals to move between access networks with minimal disruption, the terminals should be able to maintain multiple active network connections. Such a multihomed mobile host will experience different capabilities and coverage area depending on the access technologies. This paper proposes and evaluates an extension to Mobile IPv6 enabling multihoming, regardless of the access technology. Mobility of multimedia communication in this environment should adapt to changing conditions and be base on dynamic measurements and user preferences. The proposed architecture gives opportunities for mobile multimedia applications to use multiple access networks simultaneously and the possibility to move individual flows. Media flows are identified by destination IP address, protocol and port number. Results from a real world prototype are presented using three different wireless access technologies: 802.11, UMTS and 802.16-2004.

  • 679.
    Kristiansson, Johan
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    On technologies for ubiquitous multimedia communication2006Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The proliferation of multimedia and deployment of wireless networks over the last decade have made it possible for users to communicate and share information using e-meeting services from almost any location at anytime. While these new services offer new ways to communicate, they are not always easy to use because of the heterogeneity of networks and devices, which must be managed by the users to take full advantage of the possible benefits. Switching to another communication service running on another terminal requires even more configuration efforts. In addition, it is expected that the configuration efforts required by the users will become more time-consuming in the future as the need for richer communication grows and the diversity of services and networks increases. This doctoral thesis proposes and evaluates new methods to create a ubiquitous multimedia communication system, which makes it easier for users to participate in online e-meetings using the most suitable network or terminal. The thesis makes several contributions related to mobility and bandwidth management. One contribution is a new mobility protocol called the Resilient Mobile Socket and an algorithm called Competition-based Soft-Handovers Management designed to manage host mobility and seamlessly migrate media streams between different network connections. To deal with bandwidth variation, the thesis proposes a method based on microeconomic theory to adapt and share bandwidth efficiently between media within an application, thereby relieving the users from manually adjusting bandwidth utilization after switching network. In regards to switching terminals, the thesis proposes a concept called media resources, and a framework for managing media resources using context-awareness. The most beneficial media resource is automatically selected using an algorithm, which is also presented in the thesis. The proposed methods, frameworks, and algorithms have been evaluated through a combination of theoretical analysis, controlled laboratory experiments, user studies, and exploratory experiments using prototypes. The results from these investigations show that it is possible to create a ubiquitous multimedia communication system that enables richer communication in mobile settings by better utilizing available networks and combining multiple terminals. A final conclusion is that it is crucial to minimize configuration efforts, but the user should always have the final decision if a configuration procedure cannot be automated with complete accuracy.

  • 680.
    Phanse, Kaustubh
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    Nykvist, Johan
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Opportunistic wireless access networks2006In: Proceedings of the 1st international conference on Access networks, New York: ACM Digital Library, 2006, article id 11Conference paper (Refereed)
    Abstract [en]

    Today, intermittent connectivity is common in wireless access networks and it seems like mobile users will have to deal with discontinuous network access in the future. But existing network protocol architectures are not resilient to disruption of communication links and often communication fails when faced with sporadic connectivity. We discuss a new paradigm for wireless access called opportunistic collaborative networking, where communication is disruption-tolerant and wireless devices exploit any opportunity of communication, albeit temporary, to forward messages towards the destination. For developing protocols for these innovative networks requires understanding of their structure and dynamics. We present some results from analysis of real-life traces representing two such mobile network environments with ad-hoc, intermittent connectivity.

  • 681.
    Åhlund, Christer
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    Brännström, Robert
    Andersson, Karl
    Tjernström, Örjan
    Port-based multihomed mobile IPv6 for heterogeneous networks2006In: Proceedings: the 31st IEEE Conference on Local Computer Networks, LCN 2006 : Tampa, Florida, U.S.A., November 14 - 16, 2006, Piscataway, NJ: IEEE Communications Society, 2006, p. 567-568Conference paper (Refereed)
    Abstract [en]

    Future wireless networks are expected to be based on coexistence of multiple different access network technologies. Mobile devices will then be equipped with multiple wireless interfaces enabling connectivity via multiple architectures. Different wireless techno-logies differ widely considering their capabilities and coverage. This requires a mobile node to maintain multiple active connections depending on the appli-cations used and available access networks. To enable this, a mobile node needs to be multihomed and able to direct traffic flows via different interfaces. This paper describes a proposal extending Mobile IPv6 with multihoming functionality. Multihoming is managed using IP address, protocol and port number.

  • 682.
    Wallin, Stefan
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    Leijon, Viktor
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Rethinking network management solutions2006In: IT Professional Magazine, ISSN 1520-9202, E-ISSN 1941-045X, Vol. 8, no 6, p. 19-23Article in journal (Refereed)
    Abstract [en]

    Telecommunication network management solutions need to shift perspective from one of network element management to service management. Operators need a service view of their network, with automatic service-impact correlation. This requires some major changes in the underlying solutions: equipment vendors must improve the supplied management interfaces and network management solutions must implement a higher degree of automation and correlation with a service focus. One obstacle is the lack of models and formalism to describe topology and service structures

  • 683.
    Nyberg, Gustav
    et al.
    Umeå universitet.
    Åhlund, Christer
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    Röjmyr, Tomas
    Umeå universitet.
    SEMO: a policy-based system for handovers in heterogeneous networks2006In: International Conference on Wireless and Mobile Communications: [ICWMC 2006] ; Bucharest, Romania, July 29 - 31, 2006 / [ed] Petre Dini, Los Alamitos, Calif: IEEE Communications Society, 2006, p. 62-Conference paper (Refereed)
    Abstract [en]

    A vision of future wireless networks is the coexistence of multiple access network technologies. Different access networks will coexist and the Internet Protocol will be the glue. To fulfil this vision, one of the greatest challenges is to develop sophisticated policies for vertical handovers. When and in what way the handovers are performed, affects the performance of the mobile services. Traditional handover policies are based on received signal strength comparison. To be able to support vertical handover, policies have to consider parameters such as capacity, utilization cost, power consumption, security and QoS guarantees. This paper describes a proposal for a policy-based vertical handover model for heterogeneous networks. Analysis, design, implementation and evaluation of "SEMO", a policy-based vertical handover system, are presented.

  • 684.
    Phanse, Kaustubh
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    Akhavan, Mohammad-Reza
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    Olsson, Ulf
    LKAB.
    Study of IEEE 802.11 wireless networks in harsh environments2006In: Condition Monitoring and Diagnostic Engineering Management: COMADEM 2006 ; proceedings of the 19th international congress, Luleå, Sweden, 12 - 15 June 2006 / [ed] Uday Kumar, Luleå: Luleå tekniska universitet, 2006Conference paper (Refereed)
    Abstract [en]

    IEEE 802.11 technologies are expected to remain the popular wireless local area networking solution for home and office environments. With growing interest within the process and manufacturing industry to go wireless, these technologies are a natural choice for enabling tetherless control and maintenance. However, the use of IEEE 802.11 suite of protocols for wireless access in unconventional, harsh environments is limited and their behavior and performance in these settings is not yet well understood. A prime example of such a setting is the LKAB underground iron-ore mine in Kiruna, Sweden. LKAB envisions an economical and effective wireless access solution in the mines for increasing automation, e.g., remotely control mining equipment such as mobile loading machines and drilling equipment. In this paper, we present our experiences of operating an IEEE 802.11g based wireless network in the LKAB underground iron-ore mine. Using measurements, we characterize and model the environment and its effect on the performance of higher layer protocols. We derive the theoretical limits of IEEE 802.11g and compare them with our experimental results. We observe a highly reflective environment in the mine, which causes multipath fading and in turn, considerably degrades the maximum achievable throughput in practice.

  • 685.
    Åhlund, Christer
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    Brännström, Robert
    Zaslavsky, Arkady
    Traffic load metrics for multihomed mobile IP and global connectivity2006In: Telecommunications Systems, ISSN 1018-4864, E-ISSN 1572-9451, Vol. 33, no 1-3, p. 155-185Article in journal (Refereed)
    Abstract [en]

    Support for host mobility an essential and necessary feature for roaming users who connect to wireless networks via access points. Access points may have different capabilities, be connected to different networks and be installed by different providers. A mobile host will discover multiple access points in this environment. In such an environment, a mobile host should be able to use the best available connection to communicate with a correspondent host and perhaps use multiple connections for different hosts. In areas with wireless local area network access, pockets with limited or no coverage could exist. Such restricted connectivity could be compensated by neighbor hosts who form an ad hoc network and relay packets until they reach an access point. This paper describes and discusses a proposed solution towards enabling and supporting connectivity in wireless networks. In the proposed solution the network layer software will evaluate and decide which wireless network connections to use. A Running Variance Metric (RVM) and a Relative Network Load(RNL) are used to measure the traffic load of access points in wireless access networks. RVM and RNL can be efficiently used for both infrastructure networks and ad hoc networks. Multihomed Mobile IP (M-MIP) is an extension of Mobile IP that enables mobile hosts to use multiple care-of addresses simultaneously. The extension enhances network connectivity by enabling the mobile host, the home agent and correspondent hosts to evaluate and select the best connection. A proposed gateway architecture using M-MIP that integrates wired IP networks with ad hoc networks is described. The M-MIP and gateway architecture using the RVM and RNL metrics have been validated with simulation studies and results are presented.

  • 686. Drugge, Mikael
    et al.
    Witt, Hendrik
    TZI, Bremen.
    Parnes, Peter
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    Synnes, Kåre
    Using the "HotWire'' to study interruptions in wearable computing primary tasks2006In: Proceedings: Tenth IEEE International Symposium on Wearable Computers, ISWC 2006 : Montreux, Switzerland, October 11 - 14, 2006, Piscataway, NJ: IEEE Communications Society, 2006, p. 37-44Conference paper (Refereed)
    Abstract [en]

    As users of wearable computers are often involved in real-world tasks of critical nature, the management and handling of interruptions is crucial for efficient interaction and task performance. We present a study about the impact that different methods for interruption have on those users, to determine how interruptions should be handled. The study is performed using an apparatus called "HotWire" for simulating primary tasks in a laboratory experiment, while retaining the properties of wearable computers being used in mobile, physical, and practical tasks.

  • 687. Drugge, Mikael
    et al.
    Hallberg, Josef
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Parnes, Peter
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    Synnes, Kåre
    Wearable systems in nursing home care: prototyping experience2006In: IEEE pervasive computing, ISSN 1536-1268, E-ISSN 1558-2590, Vol. 5, no 1, p. 86-91Article in journal (Refereed)
    Abstract [en]

    The development of a wearable prototype systems after studies conducted in a nursing home care is discussed. The specific problems encountered by medical workers at nursing homes includes communication, information dissemination, access to patient charts and organizational issues. The failure of which may cause stress, discomfort, and dissatisfaction among caretakers and patients as well as possible detrimental health consequences for patients. A Wizard of Oz experiments was used to retrieve information, process interrupting phone calls, to simplify communication with others, and to minimize the interaction needed with the wearable computer.

  • 688.
    Nilsson, Marcus
    et al.
    Luleå tekniska universitet.
    Drugge, Mikael
    Liljedahl, Urban
    Synnes, Kåre
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    Parnes, Peter
    A study on users' preference on interruption when using wearable computers and head mounted displays2005In: Third IEEE International Conference on Pervasive Computing and Communications, PerCom 2005: Kauai Island, HI; 8 March 2005 through 12 March 2005, Los Alamitos: IEEE Computer Society Press , 2005, p. 149-158Conference paper (Refereed)
    Abstract [en]

    An important part of making a wearable computer un-obtrusive is the user interface and the way it interrupts the user. The amount of interruption that have to be made on the users primary task should be minimized. Usage without interruption is of course best for the performance of the primary task but is often not possible as many tasks that the wearable computer is involved in do need interaction with the user. It is therefore important to understand what type of interruption that will benefit the user most. The question about which interruption that causes the least amount of stress for the user is as important as which interruption that gives the best performance. This paper continues on previous work where performance of the users was measured for different types of interruption. In this paper subjective data is analyzed to understand how to build user interfaces for wearable computers and head mounted displays that considers stress and other subjective variables.

  • 689. Kristiansson, Johan
    et al.
    Scholl, Jeremiah
    Parnes, Peter
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    Bridging the gap between multimedia application and heterogeneous networks using a market-based middleware2005In: Proceedings: Sixth IEEE International Symposium on a World of Wireless Mobile and Multimedia Networks, WoWMoM 2005 : Taormina - Giardini Naxos, Italy, 13 - 16 June 2005 / [ed] Giuseppe Anastasi, Los Alamitos, Calif: IEEE Computer Society Press , 2005, p. 463-465Conference paper (Refereed)
    Abstract [en]

    This paper¹ presents a middleware that applies a micro-economic model to help multimedia applications utilize available bandwidth in a way that maximizes the user’s net benefit. The key components are a bandwidth broker that puts the supply of available bandwidth on a virtual market, and utility functions for each media, which are used to calculate the relative gain they can offer the user by using this bandwidth. Basic supply and demand principles are used where the broker raises the price if the total demand from all media exceeds the available supply, or lowers the price if the demand is lower than the available supply.

  • 690. Scholl, Jeremiah
    et al.
    Parnes, Peter
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    McCarthy, John D.
    University College London.
    Sasse, Angela
    University College London.
    Designing a large-scale video chat application2005In: ACM Multimedia 2005: proceedings of the 13th ACM International Conference on Multimedia, November 6-11, 2005, Singapore, New York: ACM Digital Library, 2005, p. 71-80Conference paper (Refereed)
    Abstract [en]

    Studies of video conferencing systems generally focus on scenarios where users communicate using an audio channel. However, text chat serves users in a wide variety of contexts, and is commonly included in multimedia conferencing systems as a complement to the audio channel. This paper introduces a prototype application which integrates video and text communication, and describes a formative evaluation of the prototype with 53 users in a social setting. We focus the evaluation on bandwidth and view navigation requirements in order to determine how to better serve users with video chat, and discuss how the findings from this evaluation can inform the design of future video chat applications. Bandwidth requirements are evaluated through user perceptions of video delivered using three different bandwidth schemes. For view navigation, we examine a system that automatically switches the video focus to the current "chatter", instead of requiring users to navigate manually to find the video steam they are interested in viewing.

  • 691.
    Åhlund, Christer
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    Extended mobile IP and support for global connectivity in hybrid networks2005Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Mobility is an essential and necessary feature for roaming users who connect to wireless networks via access points. Access points may have different capabilities, be connected to different networks and be installed by different providers. A mobile host will discover multiple access points in this environment. A mobile host should be able to use the best available connectivity to communicate with a correspondent host and perhaps use multiple connections for different hosts. In areas with wireless local area network access, pockets with limited or no coverage could exist. Such restricted connectivity could be compensated by neighbor hosts who form an ad hoc network and relay packets until they reach an access point. This thesis describes and discusses the proposed solutions towards enabling and supporting connectivity in wireless access networks. In the proposed solutions the network layer software will evaluate and decide which wireless network connections to use. This thesis proposes a Running Variance Metric (RVM) and a Relative Network Load (RNL) as performance metrics to classify the traffic load of access points in wireless access networks. RVM and RNL can be efficiently used for infrastructure networks and ad hoc networks. This thesis proposes an extension to Mobile IP in order to enable mobile hosts to use multiple care-of addresses simultaneously. These extensions enhance network connectivity by enabling the mobile host, the home agent and correspondent hosts to evaluate and select the best connection. The proposed extension to Mobile IP is called Multihomed Mobile IP to emphasize support for multiple connections for a mobile host at the same time. This thesis describes a proposed gateway architecture that integrates wired IP networks with ad hoc networks. Routes between a mobile host and gateways are maintained continuously where multi-hop ad hoc connections are supported. Communication between peers in ad hoc networks is based on reactive ad hoc routing. Mobile hosts moving between ad hoc networks are supported by Multihomed Mobile IP. This thesis describes developed prototypes and simulation results to validate multihomed Mobile IP and the gateway architecture which integrates ad hoc networks and wired IP networks.

  • 692.
    Lindgren, Anders
    et al.
    Kungliga tekniska högskolan, KTH.
    Phanse, Kaustubh
    Johansson, Tomas
    Brännström, Robert
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    Åhlund, Christer
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    Future directions in ad hoc networking research2005In: 5th Scandinavian Workshop on Wireless Ad-hoc Networks: ADHOC ´05, Stockholm: Wireless at KTH, Royal institute of technology , 2005Conference paper (Other academic)
    Abstract [en]

    Much effort has gone into mobile ad-hoc network (MANET) research over the past decade. Yet, even today, mobile ad-hoc networking is seen as a relatively new area of research. The reason for this can be traced to the fact that the maturity in truly understanding these networks is still alarmingly low and actual deployment of these networks rare. In this paper, we investigate the reasons for this lack and suggest ways for overcoming the shortcomings. We then describe four sub-topics in ad hoc networking that have not received much attention, but are crucial for making real deployment of MANETs feasible.

  • 693. Phanse, Kaustubh
    et al.
    DaSilva, L.
    Midkiff, S.
    Park, J.
    Hadjichristofi, G.
    Lin, T.
    Davis, N.
    Interoperable security, routing and quality of service for ad-hoc network mobility2005In: Military communications: papers and posters presented at the symposium organised by the Information Systems Technology Panel (IST) in Rome, Italy, 18-19 April 2005 = Les communications militaires, Neuilly-sur-Seine: NATO Research and Technology Organisation , 2005Conference paper (Refereed)
  • 694.
    Channakeshava, Karthik
    et al.
    Virginia Tech, Blacksburg, Virginia.
    Phanse, Kaustubh
    DaSilva, Luiz A.
    Virginia Tech, Blacksburg, Virginia.
    Ravindran, Binoy
    Virginia Tech, Blacksburg, Virginia.
    Midkiff, Scott F.
    Virginia Tech, Blacksburg, Virginia.
    Jensen, E. Douglas
    MITRE Corporation, Bedford, MD.
    IP quality of service support for soft real-time applications2005In: Proceedings - RTN 2005, 4th Intl. Workshop on Real-Time Networks (formerly RTLIA: Palma de Mallorca, Spain, July 5, 2005 ; satellite event to ECRTS 2005, 6 - 8 July, Palma de Mallorca, Spain / [ed] Jörg Kaiser, Magdeburg: Otto-von-Guericke Univ , 2005Conference paper (Refereed)
    Abstract [en]

    To obtain acceptable timeliness performance for emerging large-scale distributed real-time control applications operating in large IP internetworks, a scalable quality of service (QoS) architecture is needed. In this paper, we propose a scalable QoS architecture (abbreviated as RTQoS) in support of real-time systems, one that implements real-time scheduling at end-hosts and stateless QoS in the core routers. We address challenges and explore potential benefits achieved by integrating network services with real-time systems, through the use of a network testbed. Experimental evaluation demonstrates the RTQoS architecture as a promising approach for soft real-time applications that are subject to time/utility function time constraints and utility accrual optimality criteria.

  • 695.
    Parviainen, Roland
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    Large scale and mobile group communication systems2005Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This doctoral thesis examines different attributes of large scale group communication systems such as scalability, security and mobility by studying two different prototype systems - mIR (multicast Interactive Radio) and MES (Mobile E-meeting Services). mIR is a system for large scale real-time music distribution, designed as an interactive radio system for the Internet. MES is a collection of tools for improving the use of e-meeting and video conferencing tools in a mobile environment. The mIR prototype has been used to study scalability and security. Scalability in mIR concerns how to support as many users as possible without degrading the experience. This is achieved using IP multicast together with algorithms that limits the bandwidth usage regardless of the number of users. The work on security have focused on copy prevention through digital watermarking. By adding a unique watermark, i.e. a fingerprint, to each media copy a pirated copy can be traced back to a specific user, which can act as a deterrent. The thesis shows how we can combine the different goals of fingerprinting and IP-multicast while still maintaining the scalability features of multicast. Many issues need to be considered if e-meetings and video conferencing will become widespread and popular. Scalability and security, discussed in the first part of the thesis are two examples, and the second part of the thesis tries to address a third issue: mobility. In particular we are interested in enabling access to an e-meeting in a mobile environment, where we often have difficult conditions such as bad network connections, the user only have access to the Internet through a web browser or the available devices are small and limited. In many cases it is currently impossible to participate in an e-meeting when you're not in the office. The prototype system developed in the second part of the thesis aims to enable participation from any location and device that have some sort of Internet connection. We try to achieve this by allowing a mobile user to access an e-meeting session from a web browser or from a Java enabled mobile phone. Further, the system makes it possible to review missed events in an e-meeting as it is likely that there are many times where no Internet connection at all is available. The general style of work has been prototype driven with a goal of creating usable prototypes - i.e. the prototypes should be easy to deploy and it should be possible to use and test the prototypes daily. Most the prototypes described in this thesis have indeed been deployed and have seen daily use.

  • 696.
    Brännström, Robert
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    Åhlund, Christer
    Zaslavsky, Arkady
    Maintaining gateway connectivity in multi-hop ad hoc networks2005In: Proceedings: the IEEE Conference on Local Computer Networks, 30th anniversary : Sydney, Australia, November 15 - 17, 2005, Los Alamitos, Calif: IEEE Computer Society Press , 2005, p. 682-689Conference paper (Refereed)
    Abstract [en]

    The need for maintaining gateway connectivity in an ad hoc access network is vital considering the 80/20 ratio of Internet traffic. There are several proposals of how to integrate gateway forwarding strategies but they all rely on the route discovery procedure of reactive routing protocols. We propose a proactive approach to avoid the delay of the route discovery process. Mobile IP is often suggested to handle macro mobility and we use the advertisements periodically sent by the gateway to update routing tables in the ad hoc network. Since advertisements may arrive to a mobile host through multiple paths, it is important to keep track of the best path to each gateway. We demonstrate the use of a proposed dynamic metric and how to handle location of correspondent hosts. A simulation study demonstrates the usefulness and efficiency of our approach.

  • 697. Kristiansson, Johan
    et al.
    Scholl, Jeremiah
    Parnes, Peter
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    Managing bandwidth in multimedia applications using a market-based middleware2005In: Management of Multimedia Networks and Services: 8th International Conference on Management of Multimedia Networks and Services, MMNS 2005, Barcelona, Spain, October 24-26, 2005. Proceedings / [ed] Jordi Dalmau Royo, Berlin: Encyclopedia of Global Archaeology/Springer Verlag, 2005, p. 216-227Conference paper (Refereed)
    Abstract [en]

    This paper presents an application-layer middleware that applies a microeconomic model to help multimedia applications utilize available bandwidth in a way that maximizes the user’s net benefit. The key components are a bandwidth broker that puts the supply of available bandwidth on a virtual market residing inside the application, and utility functions for each media, which are used to calculate their relative gain to the user at each bandwidth level. Basic supply and demand principles are used where the broker raises a virtual price if the total demand from all media exceeds the available supply, or lowers the price if demand is lower than the available supply. The advantage of the middleware is that it allows problems related to network management (usually affecting the supply) and human computer interaction (usually affecting demand) to be researched and integrated separately into an application and combined to leverage bandwidth in the best possible way. As a proof of concept, a prototype has been built by integrating the middleware into Marratech Pro, a commercially available e-meeting application. The paper presents experimental results using this prototype

  • 698.
    Åhlund, Christer
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    Brännström, Robert
    Zaslavsky, Arkady
    M-mip: extended mobile ip to maintain multiple connections to overlapping wireless access networks2005In: Networking - ICN 2005: 4th International Conference on Networking, Reunion Island, France, April 17 - 21, 2005; / [ed] Pascal Lorenz, Berlin: Encyclopedia of Global Archaeology/Springer Verlag, 2005, p. 204-213Conference paper (Refereed)
    Abstract [en]

    In future wireless access networks, connectivity to wired infrastructure will be provided through multiple access points with possibly different capabilities and utilization. The demand for increased network performance requires the ability to predict the best overall performance of those access points and to switch access point when the performance changes. Then there is the demand for mobility between networks with maintained connectivity which requires the ability to switch the point of attachment. We propose Multihomed Mobile IP, enabling performance discovery at the networks layer and the capability to decide what AP to use. Mobile IP support is needed to allow mobile hosts to move between networks with maintained connectivity. Multihomed Mobile IP enables mobile hosts to register multiple care-of addresses at the home agent, to enhance the performance of wireless network connectivity. This article describes a simulator evaluation of multihomed Mobile IP.

  • 699.
    Brännström, Robert
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    Network-layer mobility in wireless ad hoc access networks2005Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis proposes and discusses solutions to enable network-layer mobility in wireless ad hoc access networks. The deployment of wireless access networks has made them ubiquitous and current research strives to make them pervasive. Users having wireless access to wired IP networks and the Internet are driving the demand for mobile and heterogeneous solutions. To enable all kinds of mobility in heterogeneous All-IP networks there are many issues to be solved. This thesis focuses on network-layer mobility and connectivity of wireless multi-hop ad hoc networks to the Internet. In a wireless environment with overlapping service areas, mobile hosts need to select which gateway(s) to use to access the wireless infrastructure. The signal-to-noise ratio of an access point, which is part of a wireless LAN, does not reflect the number of attached hosts or the traffic between them. The throughput of the access point could be low while the signal is strong. At the same time an access point with weaker signal could allow higher throughput. In ad hoc routing, hop count is the most common metric and the selection of a route to a gateway is affected by the same utilization problem. This could lead to a situation where a short route is used by more hosts and performing worse than a longer route serving fewer hosts. This thesis proposes and discusses solutions to calculating network-layer metrics and using them in gateway selection and handover decisions. To enable connectivity of a mobile ad hoc network (MANET) to the Internet, a gateway must support the wired single-hop and wireless multi-hop approaches. To deploy network-layer mobility in a MANET, the Mobile IP protocol needs to be adapted for the multi-hop environment. A MANET enables connectivity to more than one gateway at a time and combined with multihoming it provides seamless handover between subnets. The gateway selection and handover decisions are complicated by the multihoming capabilities. This thesis proposes and discusses solutions to deploying multihomed mobility into MANETs and thereby handling multi-hop gateway discovery, registration of multiple gateways and tunneling to selected gateway(s). Traffic patterns in wired LANs generally follow the 80/20 ratio of Internet destined vs. local traffic. The same traffic patterns generally hold true for wireless hosts. Therefore it is important to maintain the route to the gateway for the Internet destined traffic. This thesis proposes and discusses a solution to maintaining gateway connectivity in MANETs by installing routes to gateways using advertisements. Deciding the locality of a peer and setting up the forwarding route differs between single-hop and multi-hop networks. In single-hop networks a source matches the destination prefix with its own to decide what forwarding policy to use. Local traffic is sent directly to the destination with the link- layer protocol while global traffic is forwarded to a default gateway. In multi-hop networks the ad hoc routing protocol finds the route to a destination either proactively or on-demand. This thesis proposes and discusses a solution to deciding on the mobile host destination locality in a MANET.

  • 700. Drugge, Mikael
    et al.
    Hallberg, Josef
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Synnes, Kåre
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    Parnes, Peter
    Relieving the medical workers' daily work through wearable and pervasive computing2005In: ICE2005: the 11th International Conference on Concurrent Enterprising : integrated engineering of products, services and organisations, Munich, Germany 20-22 June 2005, Nottingham: Centre for concurrent enterprising, University of Nottongham , 2005Conference paper (Refereed)
    Abstract [en]

    We intend to relieve the daily work at care-centers, allowing medical workers to focus on the patients and their needs. This goal can be achieved by employing technology that automate and simplify tasks previously requiring tedious interventions, giving more time for the important human to human interaction. For any technology to become accepted by the medical workers, we must ensure that it is highly natural and unobtrusive, without interfering with their caregiving. By studying the medical workers’ daily work, we can draw conclusions on what problems they encounter, allowing us to develop prototypes which can be deployed and used at the care-centers. In doing this, we can proceed to study the acceptance and usability of our proposed solution, and see whether and how it solves the problem. In this position paper, we present our current and future research in wearable and pervasive health-care.

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