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Publicações

Publicações por CRAS

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.

2015

REX 2014-Robotic Exercises 2014 Multi-robot field trials

Autores
Marques, MM; Martins, A; Matos, A; Cruz, N; Almeida, JM; Alves, JC; Lobo, V; Silva, E;

Publicação
OCEANS 2015 - MTS/IEEE WASHINGTON

Abstract
Today there are different teams specializing in different areas such as shipwrecked rescue, searching for mines, environmental monitoring, border surveillance, traffic control, search and rescue and harbor protecting. Robotic systems and unmanned vehicles can provide additional capabilities and new innovative solutions that contribute to these applications. This paper presents the Robotic Exercises 2014 (REX'14) and the lessons learned with various field experiments performed with multiple unnamed systems in the context of the Portuguese Navy concept of operations. During the REX'2014 multiple experiments and systems were operated. Autonomy and environment characterization and assessment missions were performed with autonomous surface vehicles such as the ROAZ autonomous surface vehicle or with autonomous underwater vehicle MARES. Autonomy and system validation was performed for fast water jet propelled surface systems such as the SWIFT autonomous surface vehicle and the ICARUS unmanned rescue capsule, wind propulsion tests were also performed with unnamed surface vehicles and new maritime wireless communication protocols were tested.

2015

Integration of Wind Propulsion in an Electric ASV

Autores
Cruz, NA; Alves, JC; Guedes, T; Rodrigues, R; Pinto, V; Campos, D; Silva, D;

Publicação
Robotic Sailing 2015

Abstract

2015

Message from the general chairs

Autores
Matos, JS; Alves, JC;

Publicação
Proceedings - 41st Euromicro Conference on Software Engineering and Advanced Applications, SEAA 2015

Abstract

2015

Message from the General Chairs

Autores
Matos, JS; Alves, JC;

Publicação
Proceedings - 18th Euromicro Conference on Digital System Design, DSD 2015

Abstract

2015

A Centralized Approach to the Coordination of Marine Robots

Autores
Ferreira, BM; Matos, AC; Cruz, NA; Moreira, AP;

Publicação
CONTROLO'2014 - PROCEEDINGS OF THE 11TH PORTUGUESE CONFERENCE ON AUTOMATIC CONTROL

Abstract
This paper presents a centralized coordination scheme for multiple marine vehicles. The only requirements for proper operation of this method are the presence of bidirectional communication links with a virtual leader and bounded reference tracking errors. By relying on a, lower level, individual position tracking control, coordination is achieved by means of a centralized potential-field that uniquely defines the desired formation geometry as well as its position. The formation can be driven along a path that does not necessarily need to be predefined. Instead, a virtual leader defines the formation position at each instant of time. Furthermore, the possibility of setting stationary points over the path followed by the formation is guaranteed. The approach is illustrated in practice with autonomous surface vehicles in real environment, subjected to disturbances such as wind and waves.

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