In the presence of noncompact symmetry, the stability of relative equilibria under momentum-preserving perturbations does not generally imply robust stability under momentum-changing perturbations. For axisymmetric relative equilibria of Hamiltonian systems with Euclidean symmetry, we investigate different mechanisms of stability: stability by energy-momentum confinement, KAM, and Nekhoroshev s...

Advances in low-power electronics design and wireless communication have enabled the development of low cost, low power micro-sensor nodes. These sensor nodes are capable of sensing, processing and forwarding which have many applications such as underwater networks. In underwater wireless sensor networks (UWSNs) applications, sensors which are placed in underwater environments and predicted ena...

The development of two new classes of commercial underwater robotic vehicles – deep diving work-class remotely operated vehicles and survey-class autonomous vehicles – is being driven by the needs of deep water oil production and deep ocean telecommunication cable operations. This paper presents a survey of the present state and future directions of commercial underwater robotics, examines prin...

As industrial activities continue to grow on the Brazilian coast, underwater sound measurements are becoming of great scientific importance as they are essential to evaluate the impact of these activities on local ecosystems. In this context, the use of commercial underwater recorders is not always the most feasible alternative, due to their high cost and lack of flexibility. Design and constru...

Underwater cameras are widely used to observe the sea floor. They are usually included in autonomous underwater vehicles (AUVs), unmanned underwater vehicles (UUVs), and in situ ocean sensor networks. Despite being an important sensor for monitoring underwater scenes, there exist many issues with recent underwater camera sensors. Because of light’s transportation characteristics in water and th...

Reliability and energy efficiency are the crucial issues for construction of Underwater Acoustic Networks (UANs). Many schemes have been developed to improve reliability and energy efficiency in UANs. However, most of the existing schemes are based on the unrealistic assumptions that the noise in the underwater surrounding is uniformly distributed and the attenuation of noise is not considered....