In this dissertation, the traditional Gabor represantation with sinusoidal basis functions, which is widely used in the time-frequency analysis of non-stationary signals, is extended to the Fractional Gabor expansion with fractionally modulated basis functions. The completeness and biorthoganility conditions of the analysis and synthesis basis sets of the expansion are derived. Then, a discrete fractional…
Witnessing the omnipresence of ever complex yet so intuitive digital video media, research community has raised the question of its meaningful use and management. Stored in immense multimedia databases, digital videos need to be retrieved and structured in an intelligent way, relying on the content and the rich semantics involved. Therefore, the third generation of…
Con dence measures for the results of speech/speaker recognition make the systems more useful in the real time applications. Con dence measures provide a test statistic for accepting or rejecting the recognition hypothesis of the speech/speaker recognition system. Speech/speaker recognition systems are usually based on statistical modeling techniques. In this thesis we de ned con dence measures for statistical…
This thesis includes a collection of papers that analyze and derive the properties of Ultra Wideband (UWB) radio systems that use Time Hopping for Multiple Access and binary Pulse Position Modulation. New families and generation methods of Time Hopping codes are proposed and properties in terms of cross -correlation, SNR, error probabilities are given. Moreover,…
This dissertation is devoted to the analysis of fairness at the physical layer in multi-antenna multi-user communications, which implies a new view on traditional techniques. However, the degree of equality/inequality of any resource distribution has been extensively studied in other fields such as Economics or Social Sciences. Indeed, engineers usually aim at optimizing the total…
This Ph.D. dissertation addresses the design of multi-antenna systems, where the most general case corresponds to a transmitter and a receiver with more than one antenna, i.e., a multiple-input-multiple-output (MIMO) channel. The main advantage is that they can provide a much better performance than single-antenna systems, both in terms of transmission quality and system capacity,…
Since several years, multi-antenna systems are foreseen as a potential solution for increasing the throughput of future wireless communication systems. The aim of this thesis is to study and to improve the transmitter and receiver’s techniques of these MIMO (Multiple Input Multiple Output) systems in the context of a multi-carrier transmission. On the one hand,…
To measure the speed of a vehicle, the revolution of a wheel or a rigid axle is traditionally used. Therefore non corrigible systematic errors occur which are caused by slip, spin and by the change of wheel diameter due to fretting. Train control and traction systems require new robust as well as precise methods of…
Dans cette th?se, nous explorons premi?rement la notion de directionnalit? lors de la conception de rep?res d’ondelettes du plan. Cette propri?t?, qui semble essentielle pour la vision biologique, donne lieu ? une meilleure repr?sentation des contours d’ob jets dans les d?compositions d’images utilisant ces rep?res. Elle g?n?re en outre une redondance suppl?mentaire qui, exploit?e ?…
