2010
Authors
Ferreira, P; Ferreira, JC; Alves, JC;
Publication
International Conference on Field Programmable Logic and Applications, FPL 2010, August 31 2010 - September 2, 2010, Milano, Italy
Abstract
The Erlang programming language is a concurrency oriented functional language, based on the notion of independent processes and uses message passing for communication between processes. It is specially adapted to the realization of highly reliable distributed systems. In this paper it is analyzed the use of the Erlang's computational paradigm for the design and implementation of application specific heterogeneous computational systems. The main objective is to use for the low level implementation the same computational model used in high level view of the system. This will allow an easier and faster design space exploration and optimization. © 2010 IEEE.
2012
Authors
dos Santos, PV; Alves, JC; Ferreira, JC;
Publication
2012 INTERNATIONAL CONFERENCE ON RECONFIGURABLE COMPUTING AND FPGAS (RECONFIG)
Abstract
Cellular Genetic Algorithms (cGAs) exhibit a natural parallelism that makes them interesting candidates for hardware implementation, as several processing elements can operate simultaneously on subpopulations shared among them. This paper presents a scalable architecture for a cGA, suitable for FPGA implementation. A regular array of custom designed processing elements (PEs) works on a population of solutions that is spread into dual-port memory blocks locally shared by adjacent PEs. A travelling salesman problem with 150 cities was used to verify the implementation of the proposed cGA on a Virtex-6 FPGA, using a population of 128 solutions with different levels of parallelism (1, 4, 16 and 64 PEs). Results have shown that an increase of the number of PEs does not degrade the quality of the convergence of the iterative process, and that the throughput increases almost linearly with the number of PEs. Comparing with a software implementation running in a PC, the cGA with 64 PEs has shown a 45x speedup.
2011
Authors
Cardoso, JMP; Diniz, PC; Petrov, Z; Bertels, K; Hübner, M; van Someren, H; Gonçalves, F; de Coutinho, JGF; Constantinides, GA; Olivier, B; Luk, W; Becker, J; Kuzmanov, G; Thoma, F; Braun, L; Kühnle, M; Nane, R; Sima, VM; Krátký, K; Alves, JC; Ferreira, JC;
Publication
Reconfigurable Computing
Abstract
2012
Authors
Xiao, L; Alves, JC; Cruz, NA; Jouffroy, J;
Publication
2012 OCEANS
Abstract
This paper briefly presents the main points on the development and testing of an extremum seeking controller used to maximize the longitudinal velocity of surface sailing vehicles by changing the angle of the sail. The algorithm is suitable for sailing purposes since it requires only the measurements of the vehicle's velocity and the sail angle. As an illustration, we present a few simulation results on our previously-obtained sailing yacht simulator, which was developed based on a 4 DOF nonlinear dynamic model for surface sailing vehicles, showing that the proposed extremum seeking controller is capable of maximizing the sailing yacht's speed performance through online sail tuning. Furthermore, the proposed sail optimization algorithm is tested at sea on an experimental platform, i.e. a small scale autonomous sailboat, illustrating the potential of the controller.
2008
Authors
Alves, JC; Cruz, NA;
Publication
OCEANS 2008, VOLS 1-4
Abstract
Sailing has been for long times the only means of ship propulsion at sea. Although the performance of a sailing vessel is well below the present power driven ships, either in terms of navigation speed and predictability, wind energy is absolutely renewable, clean and free. Unmanned autonomous sailing boats may exhibit a virtually unlimited autonomy and be able to perform unassisted missions at sea for long periods of time. Promising applications include oceanographic and weather data collecting, surveillance and even military applications. The Microtransat competition, launched in Europe in 2006, has been a key initiative to promote the development of robotic unmanned sailing boats. Various regattas have taken place across Europe and the ultimate challenge will be a transatlantic race. This paper presents an autonomous sailing boat developed at the University of Porto, Portugal, with emphasis on the hardware and software computing infrastructure. This platform is capable of carrying a few kilograms of sensing equipment that can be hooked to the boat's main computer, also providing support for short and long range data communications.
2008
Authors
Cruz, NA; Alves, JC;
Publication
OCEANS 2008, VOLS 1-4
Abstract
Autonomous sailboats are robotic vessels that use wind energy for propulsion and control the sails and rudders without human intervention. 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. Currently, most of the limitations have been surpassed, with the availability of extremely low power electronics, flexible computational systems, reliable communication devices 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.
The access to the final selection minute is only available to applicants.
Please check the confirmation e-mail of your application to obtain the access code.