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A federation approach for security in future distributed service delivery platforms for mobile users offers some key advantages over an integrated solution relying on a common choice of a standardized authentication technology. By agreeing on an exchange protocol for security assertions rather than on the detailed security mechanisms, Service Aggregators and Access Network Operators will be able to...
This paper discusses the concept of adaptive wavelets and their application to signal compression and classification. When wavelet non-linear functions are used in the neurons of a neural network we can estimate the wavelet parameters—scale and translation and the relative importance (weight) of each basis function optimally with respect to approximating a given function (signal) in the minimum mean...
Multi-topology routing is a new strategy to provide traffic-engineering and resilience in IP networks. In case of network failures, affected traffic demands are routed in intact sub-topologies for which the routing information is predetermined. This paper investigates an optimal design of the topologies with respect to a shortest path protection routing. We formulate mathematical programs for global...
The peer-to-peer (P2P) paradigm not only allows end users to share own resources, but is also regarded as a new networking paradigm due to its robust, self-organizing character, abandoning infrastructure and relying on end-users equipment. In contrast to common fixed-line Internet file sharing P2P systems, in this paper, we address critical issues regarding scalable personal communications and heterogeneous...
In this paper, we have proposed a heterodyne technique to generate an optical millimeter-wave signal for ultra-wideband communication. First, we have investigated the characteristics of semiconductor lasers locked to another semiconductor under the RF modulation having many sidebands. The RF-modulated master laser is represented by a series of Bessel functions. This model is then inserted into Lang's...
In this paper, we address the problem of capacity assignment (CA) for latency-sensitive traffic in multi-service IP networks. The CA problem is formulated as an optimization problem with nonlinear constraints, where the total link capacity shares allocated to the given service are minimized subject to performance constraints in terms of end-to-end delay requirements. We introduce a new extension to...
This paper seeks to provide the analysis of a model of two overflow traffic components that originated from several Poisson traffics served by a common primary trunk group. Overflow parts of two of them are served in a secondary trunk group, but with changed and different serving intensities. The general solution of the system was obtained by generating function techniques, and call losses, time losses...
The determined component values by means of conventional approach to the design of analogue electronic circuits, typically do not coincide with all manufactured standard values and the designer selects the nearest standard value, thus causing a design deviation. In general, a better set of standard values will exist in the discrete domain of standard component values. However, this set will be in...
Medium access using the distributed coordination function of IEEE 802.11 is not efficient in wireless multihop networks if the devices are equipped with beamforming antennas. This paper proposes a distributed MAC protocol that goes completely away from the spatial reservation scheme of 802.11. It facilitates the use of beamforming antennas by following an announcement-objection scheme: a potential...
Security for ad hoc network environments has received a lot of attention as of today. Previous work has mainly been focussing on secure routing, fairness issues, and malicious node detection. However, the issue of introducing and conserving trust relationships has received considerably less attention. In this article, we present a scalable method for the use of public key certificates and their revocation...
ASON/GMPLS is promoted as one of the key technologies to reduce operational expenditures (OPEX) of network operators, since it provides the tools for automating the network operations. This paper gives a detailed model and qualitative analysis of the major OPEX-affecting operation processes in the area of core and metropolitan area transport networks. Moreover, a first quantitative evaluation of the...
In today's networks, mobile terminals may be provided with advanced services. In order to avoid re-initialization from scratch after a handover, the so-called context of these services may either be transferred to the new Wireless LAN access point, or the respective data stream may be forwarded from the service instead. However, committing context transfers for fast terminals infers unnecessary expenses,...
This paper proposes the application of the Single Univalve Segment Assimilating Nucleus (SUSAN) algorithm for the reduction of coding artifacts in wavelet video-coding schemes. The SUSAN filter is as an image-structure preserving non-linear filter with low computational complexity. The filter adapts its bandwidth and stop-band attenuation based on a simple pixel classification procedure. In addition...
Space–time coding is an effective approach to increase the data rate and capacity of a wireless communication system that employs multiple transmit and multiple receive antennas. It involves coding techniques that are designed for multiple transmit antennas. We apply the analytical constant modulus algorithm (ACMA) for blind channel estimation (no use of training sequences) of space–time coded systems...
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