2014
Autores
Cota, MP; Barroso, J; Ferreira, SBL; Fonseca, B; Mikropoulos, TA; Paredes, H;
Publicação
DSAI
Abstract
2014
Autores
Cruz, F; Rocha, R; Goldstein, SC; Pfenning, F;
Publicação
THEORY AND PRACTICE OF LOGIC PROGRAMMING
Abstract
We have designed a new logic programming language called LM (Linear Meld) for programming graph- based algorithms in a declarative fashion. Our language is based on linear logic, an expressive logical system where logical facts can be consumed. Because LM integrates both classical and linear logic, LM tends to be more expressive than other logic programming languages. LM programs are naturally concurrent because facts are partitioned by nodes of a graph data structure. Computation is performed at the node level while communication happens between connected nodes. In this paper, we present the syntax and operational semantics of our language and illustrate its use through a number of examples.
2014
Autores
Rocha, P; Rodrigues, R; Gomes, AM; Toledo, FMB; Andretta, M;
Publicação
IFAC Proceedings Volumes (IFAC-PapersOnline)
Abstract
This paper analyses distinct methods to represent a polygon through circle covering, which satisfy specific requirements, that impact primarily the feasibility and the quality of the layout of final solution. The trade-off between the quality of the polygonal representation and its derived number of circles is also discussed, showing the impact on the resolution of the problem, in terms of computational efficiency. The approach used to tackle the Nesting problem in strip packing uses a Non-Linear Programming model. Addressing these problems allows to tackle real world problems with continuous rotations. © IFAC.
2014
Autores
Severino, R; Pereira, N; Tovar, E;
Publicação
SPRINGERPLUS
Abstract
While Cluster-Tree network topologies look promising for WSN applications with timeliness and energy-efficiency requirements, we are yet to witness its adoption in commercial and academic solutions. One of the arguments that hinder the use of these topologies concerns the lack of flexibility in adapting to changes in the network, such as in traffic flows. This paper presents a solution to enable these networks with the ability to self-adapt their clusters' duty-cycle and scheduling, to provide increased quality of service to multiple traffic flows. Importantly, our approach enables a network to change its cluster scheduling without requiring long inaccessibility times or the re-association of the nodes. We show how to apply our methodology to the case of IEEE 802.15.4/ZigBee cluster-tree WSNs without significant changes to the protocol. Finally, we analyze and demonstrate the validity of our methodology through a comprehensive simulation and experimental validation using commercially available technology on a Structural Health Monitoring application scenario.
2014
Autores
Doroftei, D; Matos, A; de Cubber, G;
Publicação
Applied Mechanics and Materials
Abstract
In the event of a large crisis (think about typhoon Haiyan or the Tohoku earthquake and tsunami in Japan), a primordial task of the rescue services is the search for human survivors on the incident site. This is a complex and dangerous task, which often leads to loss of lives among the human crisis managers themselves. The introduction of unmanned search and rescue devices can offer a valuable tool to save human lives and to speed up the search and rescue process. In this context, the EU-FP7-ICARUS project [1] concentrates on the development of unmanned search and rescue technologies for detecting, locating and rescuing humans. The complex nature and difficult operating conditions of search and rescue operations pose heavy constraints on the mechanical design of the unmanned platforms. In this paper, we discuss the different user requirements which have an impact of the design of the mechanical systems (air, ground and marine robots). We show how these user requirements are obtained, how they are validated, how they lead to design specifications for operational prototypes which are tested in realistic operational conditions and we show how the final mechanical design specifications are derived from these different steps. An important aspect of all these design steps which is emphasized in this paper is to always keep the end-users in the loop in order to come to realistic requirements and specifications, ensuring the practical deployability [2] of the developed platforms. © (2014) Trans Tech Publications, Switzerland.
2014
Autores
Fernandes, P; Leite, IT; Teixeira, JM; Hierro Rodriguez, A; Araujo, JP; Guerreiro, A;
Publicação
23RD INTERNATIONAL CONFERENCE ON OPTICAL FIBRE SENSORS
Abstract
In this work we show numerically the potential of using a metamaterial constituted by ordered arrays of silver nanowires as a sensor for refractive index changes of a surrounding dielectric medium. The results show a strong dependence of the reflectance spectrum on the refractive index of the dielectric medium.
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