Abstract
In this paper, we discuss some of the potential applications of small scale autonomous sailboats. The use of autonomous sailboats for ocean sampling has been tentatively proposed before, but there have been minor efforts towards the development and deployment of actual prototypes, due to a number of technical limitations and significant risks of operation. We show that, currently, most of the limitations have been surpassed, with the existing availability of extremely low power electronics, flexible computational systems and high performance renewable power sources. At the same time, some of the major risks have been mitigated, allowing this emerging technology to become an effective tool for a wide range of applications in real scenarios. We illustrate some of these scenarios and we describe the status of the current efforts being made to develop operational prototypes, with some promising results already being achieved.

Abstract
Ultra Wide Band (UWB) systems based on Multiband Orthogonal Frequency Division Multiplexing (MB-OFDM) modulation, similarly to traditional OFDM systems, are particularly sensitive to oscillators instability, as carrier and sampling frequency offsets between the transmitter and the receiver destroy the subchannel orthogonality. Precise carrier and sampling frequency offsets estimation and compensation at the receiver side are therefore necessary, and should use methods with moderate complexity due to the high system transmission rates that require fast acquisition times. We formulate algorithms that are based upon the received frequency domain symbols, where the effect of both offsets can be observed, and jointly estimate them with either a linear least squares or maximum likelihood approach. The performance of the algorithms is assessed through simulation in a realistic UWB channel scenario and compared with previous literature results.

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Abstract
In this article, we present detailed results on the fabrication and characterization of mechanically induced gratings produced by winding a string around a fiber/tube set. A comparison between the mechanical and arc-induced gratings is made, which allowed its to draw some conclusions on the formation mechanisms of the latter. The usefulness of mechanical gratings in research labs is discussed and two typical applications are. also presented. (C) 2008 Wiley Periodicals, Inc.

Abstract
A novel analytical Gaussian approximation is developed for the evaluation of the distortion spectrum introduced by a nonlinear amplifier. This method allows to consider high-order distortion contributions when the device is driven by a broadband signal with Gaussian amplitude distribution. The results are applied to a ninth-order power series model based on well known single-tone and two-tone analysis parameters. The cascade of two or more amplifiers is investigated as well providing a complete set of tools for the early system specification of broadband transceivers. Simulations shows excellent agreement even for high input power levels, when former third-order and fifth-order approximations fail to yield accurate predictions. © 2008 IEEE.

Abstract