469 research outputs found

    A personal networking solution

    Get PDF
    This paper presents an overview of research being conducted on Personal Networking Solutions within the Mobile VCE Personal Distributed Environment Work Area. In particular it attempts to highlight areas of commonality with the MAGNET initiative. These areas include trust of foreign devices and service providers, dynamic real-time service negotiation to permit context-aware service delivery, an automated controller algorithm for wireless ad hoc networks, and routing protocols for ad hoc networking environments. Where possible references are provided to Mobile VCE publications to enable further reading

    A resource management architecture for future mobile communications systems

    Get PDF
    This paper presents an overview of a hierarchical Resource Management architecture for future mobile communications systems. The architecture is designed to be generic and can therefore be adopted for a range of Radio Access Methodologies. In particular it provides a mechanism for radio resource management across airinterfaces such as those being defined for use with UMTS. Given the move towards packet-switched technologies both in the Core Network and the Radio Access Network [1], the architecture embraces the concept of statistical QoS applied to individual flows in the form of a commitment level. I

    Design and evaluation of dynamic policy-based flow redirection for multihomed mobile netwotks

    Get PDF
    This paper presents the design, implementation and evaluation of a solution for dynamic redirection of traffic flows for multihomed mobile networks. The solution was developed for a mobile user that disposes of a Personal Area Network (PAN) with a Personal Mobile Router (PMR), in order to achieve Always Best Connected(ABC) service by distributing flows belonging to different applications among the most appropriate access networks. Designed in a modular way for a NEMO based mobility and multihoming support, the proposed flow redirection solution can be easily coupled with and controlled by dynamic traffic policies that come from advanced network intelligence, according to the currently available network resources and user and application requirements. A prototype implementation was validated and assessed on a testbed as proof-of-concept

    Securing personal distributed environments

    Get PDF
    The Personal Distributed Environment (PDE) is a new concept being developed by Mobile VCE allowing future mobile users flexible access to their information and services. Unlike traditional mobile communications, the PDE user no longer needs to establish his or her personal communication link solely through one subscribing network but rather a diversity of disparate devices and access technologies whenever and wherever he or she requires. Depending on the servicesā€™ availability and coverage in the location, the PDE communication configuration could be, for instance, via a mobile radio system and a wireless ad hoc network or a digital broadcast system and a fixed telephone network. This new form of communication configuration inherently imposes newer and higher security challenges relating to identity and authorising issues especially when the number of involved entities, accessible network nodes and service providers, builds up. These also include the issue of how the subscribed service and the userā€™s personal information can be securely and seamlessly handed over via multiple networks, all of which can be changing dynamically. Without such security, users and operators will not be prepared to trust their information to other networks

    A personal distributed environment for future mobile systems

    Get PDF
    A Personal Distributed Environment (PDE) embraces a user-centric view of communications that take place against a backdrop of multiple user devices, each with its distinct capabilities, in physically separate locations. This paper provides an overview of a Personal Distributed Environment and some of the research issues related to the implementation of the PDE concept that are being considered in the current Mobile VCE work programme

    Comparison of ISMA and DECT-DCS channel access policies for indoor wireless communications systems

    Get PDF
    This letter is concerned with the assessment of channel access mechanisms for indoor 3G mobile communications systems offering packet based services. One such service in which the channel access mechanism will have a significant impact is Voice Over Internet Protocol (VOIP). This letter considers the impact of two channel allocation schemes for the indoor environment: mobile-controlled dynamic channel selection (DCS), and basestation-controlled inhibit sense multiple access (ISMA). It is shown that the DCS scheme is subject to inferior performance in packet based voice transmission due to a higher degree of front end clipping which is introduced

    Empirical modelling and simulation of transmission loss between wireless sensor nodes in gas turbine engines

    Get PDF
    Transmission loss measurements between a grid of hypothetical WSN node locations on the surface of a gas turbine engine are reported for eight frequencies at 1 GHz intervals in the frequency range 3.0 to 11.0 GHz. An empirical transmission loss model is derived from the measurements. The model is incorporated into an existing system channel model implemented using Simulink as part of a wider project concerning the development of WSNs for the testing and condition monitoring of gas turbine engines

    Rapid electron transfer reactions associated with oxygen evolution in photosystem II preparations from spinach and Phormidium laminosum

    Get PDF
    AbstractWe have measured the nanosecond kinetics of Chl-a+II reduction in oxygen-evolving detergent preparations of PS II from the cyanobacterium Phormidium laminosum and from higher plants (spinach) at 824 and 680 nm. Compared to earlier studies at 680 nm with higher plant material, we obtained an improved signal: noise ratio for measurements on a ns to ms time scale. The kinetics of Chl-a+II reduction in the ns range are consistent in the two preparations and are comparable to other studies of higher plant and cyanobacterial material. The ns kinetics are tightly connected to the ability for O2 evolution. Analysis of the Ī¼s kinetics indicates three phases: (a) the slow phase (t12 ~ 150 Ī¼s in spinach and ~ 500 Ī¼s in Phormidium) reflects the back reaction between Chl-a+II and Qāˆ’; (b) the phase with t125ā€“10 Ī¼s is probably due to a donor which is not connected to an intact water oxidation system; (c) the intermediate Ī¼s component (t12 30ā€“40 Ī¼s) may be related to water oxidation

    Multinet : enabler for next generation enterprise wireless services

    Get PDF
    Wireless communications are currently experiencing a fast migration toward the beyond third-generation (B3G)/fourth generation (4G) era. This represents a generational change in wireless systems: new capabilities related to mobility and new services support is required and new concepts as individual-centric, user-centric or ambient-aware communications are included. One of the main restrictions associated to wireless technology is mobility management, this feature was not considered in the design phase; for this reason, a complete solution is not already found, although different solutions are proposed and are being proposed. In MULTINET project, features as mobility and multihoming are applied to wireless network to provide the necessary network and application functionality enhancements for seamless data communication mobility considering end-user scenario and preferences. The aim of this paper is to show the benefits of these functionalities from the Service Providers and final User point of view

    An optimum network selection solution for multihomed hosts using Hopfield Networks

    Get PDF
    This work introduces a Hopfield Neural Network approach to network selection for multihomed hosts which considers a range of relevant network parameters including available radio access technologies and traffic types (VoIP, video streaming, Web browsing and FTP-based). Also proposed is a novel utility function that further improves network selection. Results show that, in terms of QoS, the allocation obtained using proposed algorithm outperforms other two reference allocation schemes under a range of different scenarios
    • ā€¦
    corecore