Telecommunications, 2007. AICT 2007. The Third Advanced International Conference on

Service composition technologies are very important to telecom industry today since they allow application developers to make use of existing services as building blocks to create new services in a rapid and flexible manner in order to catch the fast changing market dynamics. The building block services are usually telecom network capabilities exposed through various protocols (e.g., SIP, Parlay) ... View full abstract»

In this paper, we use the continuous- time PH/M/n/m preemptive priority queue to model the traffic behaviour between the ISP and a future HAN. From the simulated results of the model, one can then approximate the amount of bandwidth required for each traffic class per household so that the total bandwidth required is minimized while the QoS requirements (delay and blocking probability) of the home... View full abstract»

Today's computer-based annotation systems implement a wide range of functionalities that often go beyond those available in traditional paper-and- pencil annotations. Conceptually, annotation systems are based on thoroughly investigated psycho-sociological and pedagogical learning theories. They offer a huge diversity of annotation types that can be placed in textual as well as in multimedia forma... View full abstract»

BGP can be looked as a distributed algorithm to solve the stable paths problem. Routing policies conflict among ASes may cause routing divergence in Internet. Several research efforts analyze BGP convergence by describing BGP routing mechanism statically and designating BGP events in artificial sequence. In this paper, we present a stochastic high-level petri net model of simple path vector protoc... View full abstract»

The paper presents a model of a group of cells, exploiting the effects of connection handoff between cells, aimed at increasing the traffic capacity of a system. The analytical model proposed is based on the model of limited-availability group, which makes it possible to determine basic traffic characteristics in the system under consideration. The results of analytical calculations of blocking in... View full abstract»

The article proposes an analytical method for determining traffic characteristics of systems which are offered overflow traffic composed of multi-rate traffic streams. Additionally, a method for determining parameters of the traffic overflowing from primary groups and an approximate method for dimensioning systems servicing multi-service switching networks with overflow traffic are also presented. View full abstract»

In order to obtain evidence about the security strength in products we need automated information security analysis, validation, evaluation and testing approaches. Unfortunately, no widely accepted practical approaches are available. Information security testing of software-intensive and telecommunications systems typically relies heavily on the experience of the security professionals. In this st... View full abstract»

Various researchers have reported that traffic measurements demonstrate considerable burstiness on several time scales, with properties of self-similarity. Also, the rapid development of technologies has widened the scope of network and Internet applications and, in turn, increased traffic. The self-similar nature of this data traffic may exhibit spikiness and burstiness on large scales with such ... View full abstract»

We propose to use stochastic comparison method in order to compute packet loss rates in IP routers for MPLS networks. We study an IP buffer with finite capacity B and we consider two kinds of packets. Those who are delay sensitive and those who are loss sensitive. We propose a new service discipline which we denoted by "LATIN" service discipline and for buffer management; we propose to use push-ou... View full abstract»

One of the biggest challenges in ultra-wideband (UWB) radio is the accurate timing acquisition for the receiver. In this paper, we develop a simple and accurate algorithm based on minimum average error probability (MAEP) of coherent detector for pulse-level synchronization. The multipath interference (MI) problem for timing offset estimation is considered. The MSE and BER performances of our propo... View full abstract»

Muni WiFi deployments have been widely covered by the media during the last two years. However, the economical feasibility and performance of such deployments as an alternative for voice services has not been proven. In this paper we measure the voice performance and coverage of the Google network. Then we evaluate the economical feasibility versus cellular deployments. The results show that provi... View full abstract»

In this paper, a novel two-stage synchronization algorithm is proposed employing an energy capture scheme in the first stage and a correlation-and- comparison method in the second stage, fully exploiting adequate multipath component. Only one symbol observation is required to achieve frame synchronization, which speeds up the overall synchronization process with higher accuracy and lower complexit... View full abstract»

The aim of this paper is to evaluate the performance of an energy aware routing protocol, called ECB-AODV (Energy Constraint protocol Based on AODV) which derives from the AODV protocol and which is based on the local decisions of intermediate stations to maintain the connectivity of the network as long as possible. The results obtained using the network Simulator NS-2 demonstrate how small change... View full abstract»

The use of sensor networks should keep developing, mainly in such fields as scientific, logistic, military or healthcare applications. However, sensor size represents a significant limitation mainly in terms of energy autonomy and therefore of life period, for the batteries have to be too tiny. This is the reason why intensive research is being conducted nowadays on how to control sensor energy co... View full abstract»

This paper introduces two new algorithms for the minimum connected dominating set (MCDS) problem with constraints applicable to wireless network design, based on simulated annealing and tabu search principles. Each algorithm is tested on a selection of random graphs and shown to produce significantly smaller connected dominating sets when compared to a number of established methods. The simulated ... View full abstract»

Many fundamental important questions regarding Internet processes and protocols cross-layer interaction are still remained unexplored. One of the questions is network complexity as a character of network behavior. Today complexity has three distinct and almost opposite meanings. In one case, complexity is synonymous with fluctuation in traffic dynamics and the lack of predictable structure. The se... View full abstract»

One of the main challenges that face wireless multimedia communications is spectral limitations. Current second generation (2G) systems cannot support the demanding throughput requirements of the ever increasing wireless services. Third generation (3G) systems, which promised to provide a data rate of 2 Mbps for indoor users and 384 kbps for mobile users, are also unable to support the requirement... View full abstract»

The topic of policy-based management is introduced. Its specific application by the Accent project to call control is then discussed. The Appel policy language supports regular policies as well as resolution policies that deal with conflict handling. The core Appel language can be specialised, e.g. for call control. Ontologies are introduced as a means of capturing domain-specific knowledge - here... View full abstract»

Based on the good time-frequency localization of the pulse shaping, it is possible to build a multicarrier modulation that reduces both narrowband interferences and multipath channel interferences. In this paper, the given solution is based on wavelet theory: wavelet packet based multicarrier modulation is introduced and compared to the useful orthogonal frequency domain multiplexing (OFDM) modula... View full abstract»