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Publicações

Publicações por José Carlos Alves

2014

A Mission Programming System for an Autonomous Sailboat

Autores
Alves, JC; Cruz, NA;

Publicação
2014 OCEANS - ST. JOHN'S

Abstract
Robotic sailing vehicles can provide the support for carrying out long ocean sampling missions, using solely renewable energy for propulsion and for powering the computing, communication and electromechanical systems. The basic automatic sailing tasks required to visit a sequence of waypoints has already been correctly addressed by various teams. However, an effective system for specifying long term autonomous missions is necessary to fill the gap between the developers of the robotic platforms and the scientific end users, mainly interested in the data they can get. This paper presents a simple, flexible and easy to use mission programming system implemented in the autonomous sailing boat FASt. A mission is programmed by defining events and assigning to them sequences of high level actions. The support of conditional statements allows the implementation of a basic control flow mechanism to make route decisions during the deployment of the mission. Examples are presented to illustrate the construction of mission programs.

2015

AIS-Enabled Collision Avoidance Strategies for Autonomous Sailboats

Autores
Alves, JC; Cruz, NA;

Publicação
Robotic Sailing 2015

Abstract

2015

An FPGA Framework for Genetic Algorithms: Solving the Minimum Energy Broadcast Problem

Autores
dos Santos, PV; Alves, JC; Ferreira, JC;

Publicação
2015 EUROMICRO CONFERENCE ON DIGITAL SYSTEM DESIGN (DSD)

Abstract
Solving complex optimization problems with genetic algorithms (GAs) with custom computing architectures is a way to improve the execution time of this metaheuristic, which is known to consume considerable amounts of time to converge to final solutions. In this work, we present a scalable computing array architecture to accelerate the execution of cellular GAs (cGAs), a variant of genetic algorithms which can conveniently exploit the coarse- grain parallelism afforded by custom parallel processing. The proposed architecture targets Xilinx FPGAs and is used as an auxiliary processor of an embedded CPU (MicroBlaze). To handle different optimization problems, a high- level synthesis (HLS) design flow is proposed where the problem- dependent operations are specified in C++ and synthesised to custom hardware, thus requiring a minimum knowledge of digital design for FPGAs. The minimum energy broadcast (MEB) problem in wireless ad hoc networks is used as a case study. An existing software implementation of a GA to solve this problem is ported to the proposed computing array to demonstrate its effectiveness and the HLS- based design flow. Implementation results in a Virtex- 6 FPGA show significant speedups, while finding solutions with improved quality.

2014

Navigation Performance of an Autonomous Sailing Robot

Autores
Cruz, NA; Alves, JC;

Publicação
2014 OCEANS - ST. JOHN'S

Abstract
Autonomous sailing robots are a relatively new technology for oceanographic missions, targeting at long term presence in the ocean by using wind as the main source of propulsion. This paper addresses the navigation performance of FASt, an autonomous sailboat being developed in Porto, Portugal, since 2008. A series of results selected from various sea trials illustrate the accuracy of navigation and the maneuvering ability. The paper provides some quantitative performance in downwind, sidewind and upwind trajectories, with various environmental conditions. It also addresses the ability to stay within a watch circle of a few tens of meters, during the station keeping maneuver.

2014

TEC4SEA-A Modular Platform for Research, Test and Validation of Technologies Supporting a Sustainable Blue Economy

Autores
Monica, P; Martins, A; Olivier, A; Matos, A; Almeida, JM; Cruz, N; Alves, JC; Salgado, H; Pessoa, L; Jorge, P; Campos, R; Ricardo, M; Pinho, C; Silva, A; Jesus, S; Silva, E;

Publicação
2014 OCEANS - ST. JOHN'S

Abstract
This paper presents the TEC4SEA research infrastructure created in Portugal to support research, development, and validation of marine technologies. It is a multidisciplinary open platform, capable of supporting research, development, and test of marine robotics, telecommunications, and sensing technologies for monitoring and operating in the ocean environment. Due to the installed research facilities and its privileged geographic location, it allows fast access to deep sea, and can support multidisciplinary research, enabling full validation and evaluation of technological solutions designed for the ocean environment. It is a vertically integrated infrastructure, in the sense that it possesses a set of skills and resources which range from pure conceptual research to field deployment missions, with strong industrial and logistic capacities in the middle tier of prototype production. TEC4SEA is open to the entire scientific and enterprise community, with a free access policy for researchers affiliated with the research units that ensure its maintenance and sustainability. The paper describes the infrastructure in detail, and discusses associated research programs, providing a strategic vision for deep sea research initiatives, within the context of both the Portuguese National Ocean Strategy and European Strategy frameworks.

2013

Development of an Unmanned Capsule for LargeScale Maritime Search and Rescue

Autores
Matos, A; Silva, E; Cruz, N; Alves, JC; Almeida, D; Pinto, M; Martins, A; Almeida, J; Machado, D;

Publicação
2013 OCEANS - SAN DIEGO

Abstract
This paper describes the development and testing of a robotic capsule for search and rescue operations at sea. This capsule is able to operate autonomously or remotely controlled, is transported and deployed by a larger USV into a determined disaster area and is used to carry a life raft and inflate it close to survivors in large-scale maritime disasters. The ultimate goal of this development is to endow search and rescue teams with tools that extend their operational capability in scenarios with adverse atmospheric or maritime conditions.

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