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Mobile data collection is one of research highlights for sparse threedimensional underwater sensor networks. Therein, optimal or nearoptimal cruise trajectory planning of mobile sink is very crucial. A 3D Dubins curves based continuous path programming algorithm (GA-3DTSP in short) for underwater mobile sink with non-holonomic constraints such as well-known autonomous underwater vehicle is proposed. The objective of GA-3DTSP algorithm is to trace sparsely deployed sensor nodes by mobile sink so as to achieve near-optimal energy conservation efficiency. First, an extended 3D Dubins curve is proposed and the length calculation formulae for 3D Dubins curve are investigated. Furthermore, genetic algorithm is used to tackle this difficult NP-complete problem of planning shortest paths in a heuristic manner. Finally, simulation results verify that the proposed GA- 3DTSP method can conserve cruise energy of mobile sink effectively. [ABSTRACT FROM AUTHOR]

Enhancing the performance of passive target tracking and trajectory estimation of marine traffic ships is focused using a monocular camera mounted on an unmanned surface vessel. To accurately estimate the trajectory of a target traffic ship, the relative bearing and range information between the observing ship and the target ship is required. Monocular vision provides bearing information with reasonable accuracy but with no explicit range information. The relative range information can be extracted from the bearing changes induced by the relative ship motion in the framework of bearings-only tracking (BOT). BOT can be effective in crossing situations with large bearing angle changes. However, it often fails in head-on or overtaking situations due to small bearing angle changes and the resulting low observability of the tracking filter. To deal with the lack of observability, the vertical pixel distance between the horizon and the target ship in the image is used, which improves the overall target tracking performance. The feasibility and performance of the proposed tracking approach were validated through field experiments at sea. [ABSTRACT FROM AUTHOR]

In the framework of the behavioural approach, a new definition of the passive circuit component is proposed. It is based on the concept of a forwards concatenation set of an admissible trajectory. The so far elusive notion of the non-dynamic circuit component is also clarified. As an example of application, the passivity and available energy of the N-dimensional resistive, the Thévenin source, is thoroughly investigated. [ABSTRACT FROM AUTHOR]