Abstract
Is there a limit to the maximum resolution one can achieve when representing the signal's energy in the Time-Frequency plane? Some authors sustain that such a limit exists, and ignoring it is the cause of the known difficulties with some joint Time-Frequency distributions; others maintain that there is no such limit. In this article, we propose to analyze the merits and demerits of the several existing approaches, and suggest further arguments one might wish to consider. This will take us to the conclusion that, both from a tool-specific and from a general information-theoretic point of view, there is, indeed, a lower limit on the achievable resolution, even though the expression for that limit can not be given by the traditional Heisenberg-Gabor relations.

Abstract
Ville's definition of Instantaneous Frequency (IF), even though widely used and accepted, fails in most cases of practical interest. This failure has been often reported, namely in the multicomponent case. In this paper, we will analyze the advantages and shortcomings of that definition, and determine when and why it fails, integrating all previously reported cases of failure in a simple unified theory. We will also be able to extrapolate and predict the behavior of the traditional definition for any type of multicomponent signal. Alternative definitions of IF are discussed.

Abstract
In this paper we present an experimental approach for QoS-aware and bandwidth-efficient transmission of multimedia sources over ATM networks. VER video sources are statistically multiplexed at the application level and the UPC parameters of a single connection for the aggregate traffic are dynamically renegotiated with the network during the session lifetime, A statistical multiplexer computes the required bandwidth for the aggregate traffic and dynamically assigns bandwidth according to the performances requested and network resources availability. A dynamic UPC manager using feedback information sent by the network, may initiate a renegotiation of traffic parameters upon receiving a request from the statistical multiplexer. Performing the connection admission control procedures for the aggregate traffic, allows significant reductions in the value of the total peak rate when compared to the sum of peak rates of individual connections. It also reduces the burstiness of the flow submitted to the network, thus increasing the lifetime of each set of UPC parameters.

Abstract
An all fiber interrogation technique for Bragg sensors is presented. It is based on generation of an electric carrier by modulating the coupling length of a wavelength division multiplexer. Results are given when both serrodyne and sinusoidal modulation formats are considered.

Abstract
In this paper we are proposing an approach for coordinating a team of homogeneous agents based on a flexible common Team Strategy as well as on the concepts of Situation Based Strategic Positioning and Dynamic Positioning and Role Exchange. We also introduce an Agent Architecture including a specific high-level decision module capable of implementing this strategy. Our proposal is based on the formalization of what is a team strategy for competing with an opponent team having opposite goals. A team strategy is composed of a set of agent types and a set of tactics, which are also composed of several formations. Formations are used for different situations and assign each agent a default spatial positioning and an agent type (defining its behaviour at several levels). Agent's reactivity is also introduced for appropriate response to the dynamics of the current situation. However, in our approach this is done in a way that preserves team coherence instead of permitting uncoordinated agent behaviour. We have applied, with success, this coordination approach to the RoboSoccer simulated domain. The FC Portugal team, developed using this approach won the RoboCup2000 (simulation league) European and World championships scoring a total of 180 goals and conceding none. © 2001 Springer-Verlag Berlin Heidelberg.

Abstract
An all fiber technique for interrogation of interferometric low-finesse Fabry-Perot cavities is presented. It is based on the modulation of the spectral transfer function of a wavelength division multiplexer. Results are given when both serrodyne and sinusoidal modulation formats are considered.