Time filter

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Feng Y.,National University of Singapore | Liu Y.,National University of Singapore | Li Y.-F.,University of Queensland | Zhang D.,Institute National des Telecommunications
SSIRI 2010 - 4th IEEE International Conference on Secure Software Integration and Reliability Improvement | Year: 2010

The current Semantic Web ontology language has been designed to be both expressive for specifying complex concepts and decidable for automated reasoning. In recent years, the Semantic Web Rules Language has been proposed to add more expressiveness to the family of ontology languages. However the inclusion of rules has created new challenges of not only verifying the consistency of an ontology, but also checking for anomalies of a set of rules by itself. Currently automated tool support for reasoning about ontologies with rules is relatively limited compared to those for standard ontology reasoning. This paper addresses these challenges by defining notions of rule anomalies and proposing a method of discovering such anomalies by using the constraint logic programming technique and the state-of-the-art Semantic Web reasoners. © 2010 IEEE.

Cavalli A.,Institute National des Telecommunications | Lee D.,Bell Laboratories | Maag S.,Institute National des Telecommunications
Proceedings of the 6th IASTED International Conference on Software Engineering and Applications, SEA 2002 | Year: 2012

Feature interactions in communication systems manifest themselves as unexpected behaviors when multiple features are invoked jointly. We present a new approach for feature interaction detection, based on the analysis of scenarios and structures of the systems. We study the theoretical foundation of the feature interaction and propose efficient algorithms for their detection. As a case study, we also present an experiment on a real system in order to illustrate our approach.

Grosicki E.,Ecole Nationale Superieure de Telecommunication de Paris | Abed-Meraim K.,Ecole Nationale Superieure de Telecommunication de Paris | Muhammad W.,Institute National des Telecommunications
European Signal Processing Conference | Year: 2015

In this paper, a new method for the estimation of the direction-of-arrival (DOA) and relative propagation delay in the context of multipath rays is described. The proposed algorithm processes the received signals at a uniform circular array and uses ESPRIT-like approach for the estimation of the relevant parameters. We show, in particular that in the context of circular arrays, this algorithm increases drastically the accuracy of the estimated parameters with only a small number of sensors and limited processing complexity. These results encourage the use of such configurations in future wireless networks. © 2002 EUSIPCO.

Bernardo-Quintero J.,University of Antioquia | Duitama-Munoz J.F.,Institute National des Telecommunications | Duitama-Munoz J.F.,University of Antioquia
Ingenieria y Universidad | Year: 2011

Reusing models is one of the most widely accepted strategies among recent methodological approaches to software development. It is so much so that these approaches have extensively included various models with the suggestion that, in order to develop a software application, it is just necessary to build models and to transform them semi-automatically with the support of an information system. However, there are still considerable challenges in the adoption of modelfocused approaches, such as a variety of techniques, languages, and tools available for model transformation. This variety of resources complicates the standard selection of strategies for transforming models which are appropriate for a particular project or company. This paper analyzes the different model engineering approaches, as well as previous studies in model transformation, in order to serve as a guide in the selection process of model-focused approaches for software development.

Muhammad W.,Institute National des Telecommunications | Grosicki E.,ESPCI ParisTech | Abed-Meraim K.,ESPCI ParisTech | Delmas J.P.,Institute National des Telecommunications | Desbouvries F.,Institute National des Telecommunications
European Signal Processing Conference | Year: 2015

A performance comparison between radio location positioning (LP) in Wide band Code Division Multiple Access (WCDMA), more precisely in UMTS FDD cellular phones, using the Uplink (UL) and Downlink (DL) scenarios, is carried out. The radio location algorithm using the Time Difference Of Arrival (TDOA) is applied, where the TDOA is the difference between two TOA estimated at two base stations. We propose a practical algorithm to obtain high precision PL under high level interference. It consists in a matched filter followed by high resolution MUltiple SIgnal Classification (MUSIC) algorithm to estimate with a high resolution the TOA. indeed, in practice near-far resistant detection algorithms are not easy to implement directly on the received data due to the large spreading factors. The power-up and Idle Slot (IS) techniques together with Interference cancellation algorithms are used to combat the near-far problem. Simulations were carried out in the same observation conditions for UL and DL scenarios. The results show an enhancement in the LP using MUSIC algorithm after matched filtering besides, a better performance in the DL scenario. © 2002 EUSIPCO.

Delmas J.-P.,Institute National des Telecommunications | Meurisse Y.,Institute National des Telecommunications
European Signal Processing Conference | Year: 2015

This paper addresses asymptotically minimum variance (AMV) algorithms in the class of algorithms based on second-order statistics for estimating frequencies of mixed complex circular processes. To reduce the computational complexity due to the nonlinear minimization required by the matching approach, the covariance matching estimation techniques (COMET) is included in the algorithm. Numerical examples illustrate the performance of the AMV algorithm. © 2002 EUSIPCO.

Boutiouta S.,Institute National des Telecommunications | Bouizem F.,Institute National des Telecommunications | Bouderbala M.T.,Institute National des Telecommunications
Teledetection | Year: 2012

GNSS Systems (Global Navigation Satellite Systems: GPS, GLONASS, Galileo and COMPASS) have been implemented to provide global coverage and help users to determinetheir positions and reachtheir destination any time, wherever and whatever the weather conditions. Thesesystems have pavedthewayforother applications thannavigation:firstlyspaceclimate (SpaceWeather),thenmodeling of total electron content (TEC)whichsheds light on the ionosphereactivity in terms of electrondensity over a locality, region or global area, and finally, content modelingintegrated Water Vapor (IWV) in the troposphere. TEC and IWV quantities are used to make corrections of the effect of the propagation medium whichacts on the GNSS signalsdelayingthem (refractioneffect). Our work shows the different uses of GNSS measurementsat the level of the GPS Base Station "ITOB" INTTIC (Oran) in the following applications: Determination of the atmosphericerror on the GPS signals [model of Klobuchar], Modeling of the TEC in the ionosphereusing the differencetwo pseudo P1 and P2 measurementscarried out on the twofrequencies (F1=1575.42 MHz; F2=1227.60 MHz) of the GPS signals. It alsodescribes the dependence of the TEC of magneticactivity of the Earthnamed by Kpindexandthe IWV modeling in the tropospherefrom station Switzerland "ZIMMERWALD GPS measurements. Finally,thisworkdescribes the dependence of the IWV of weather conditions (temperature and pressure on the ground). © Revue Télédétection.

Delmas J.-P.,Institute National des Telecommunications
European Signal Processing Conference | Year: 2015

This paper addresses the asymptotic normal distribution of the sample covariance matrix of mixed spectra time series containing a sum of sinusoids and a linear stationary process. A new central limit theorem is proved for real or complex valued processes whose linear stationary process is possibly noncircular and not necessarily Gaussian. As an application of this result, the asymptotic normal distribution of any sinusoidal frequency estimator of such a time series based on second-order statistics is deduced. The case of the noise whitening is also considered in this general formulation. It is shown, in particular, that under mild assumptions, the asymptotic performance of most covariance-based frequency estimators is independent of the distribution of the noise. © 2000 EUSIPCO.

Kofidis E.,Institute National des Telecommunications | Regalia P.A.,Institute National des Telecommunications
European Signal Processing Conference | Year: 2015

The problem of designing an N-band biorthogonal FIR analysis/synthesis system, given K of its analysis and synthesis filters, is addressed in this paper. A necessary and sufficient condition on the K filters, that guides their selection, is derived and the solution set is completely parameterized via ladder-type structures that guarantee the perfect reconstruction property under both coefficient quantization and roundoff errors. Results are presented for both nonlinear- and linear-phase systems. A design example is provided to illustrate the theory. © 2000 EUSIPCO.

Regalia P.A.,Institute National des Telecommunications | Kofidis E.,Institute National des Telecommunications
European Signal Processing Conference | Year: 2015

By reexamining some initialization strategies for blind equalizers, we develop an approximation to a common contrast function for equalization which enjoys a 'unimodal' property: the solution obtained from the modified criterion is unique to within standard scale factor ambiguity, and moreover yields a perfect equalizer whenever such is attainable. In the more realistic situation in which perfect equalization is unattainable, the modified criterion yields a good approximation which is quantified herein, and is therefore justified as an initialization strategy. An on-line interpretation leads to an adaptive Volterra filter followed by a tensor product approximation which furnishes the coefficients of a linear equalizer, and ties in with some earlier work on equalizer design restricted to finite data sets and Volterra kernel approximations. © 2000 EUSIPCO.

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