Abstract
A vector-valued impulsive control problem is considered whose dynamics, defined by a differential inclusion, are such that the vector fields associated with the singular term do not satisfy the so called Frobenius condition. A concept of proper solution based on a reparametrization procedure is adopted which enables the derivation of optimality conditions of the Hamilton-Jacobi type. These conditions are obtained by taking a limit of those for an appropriate sequence of auxiliary "standard" optimal control problems approximating the original one. Copyright (C) 2001 IFAC.

Abstract

Abstract

Abstract
Due to the complexity of underwater transients and background interference, model based approaches to transient detection/classification are often not practical. This has motivated an interest for data-driven, model-free methods. One such method was presented in [2] and modified in [1], where it was applied to the detection of underwater transients. In this article, we will extend that approach, to allow its use in the more demanding environment of a brown water environment, where background noise is constituted by a multitude of different interferences, non-white, and highly non-stationary. Also, the assumption of linear separability amongst the transients and the background noise in the time-frequency or related domains will be discarded, leading to the use of an additional classifier stage. A technique to minimize the number of prototypes on this classifier will be presented. The developed methods are used to detect and classify real underwater transients, recorded off the Portuguese coast. Estimation of the overall error rate of the method is obtained using cross-validation with the available data set, showing that these methods can effectively be used in real environment situations.

Abstract
In this paper, we present a low-cost versatile device developed to support the navigation of autonomous underwater vehicles. Unlike the usual transponders extensively used for LBL acoustic navigation of a single vehicle, this device allows the navigation of multiple vehicles and the remote tracking of their positions, without any extra acoustic signals being transmitted. The navigation beacon has a radio buoy connected to an underwater reconfigurable multi-frequency transponder. A remote tracking station receives data from the buoy and monitors the position of the vehicles in real time. We describe the mechanical, electronic and software modules involved, as well as the tracking algorithm, and we also present experimental data from an operational mission.

Abstract
The wastewater plumes show to be very difficult to observed in detail. The several studies already conducted exhibit very complex and patchy structures both in vertical and horizontal sections. It is not clear if this plume patchiness is due to physical processes or measurement limitations. Rapid tow-yo sampling is expected to reduce the time variability during and between transects. The AUVs may be a useful instrument to map and detect wastewater plumes. This paper presents several prediction studies using time series files of actual in-situ measurements integrated in a near field model. The model predictions of the plume characteristics at the end of near field support the definition of the best sampling strategy for an AUV monitoring mission in a Portuguese west coast outfall.