2016
Autores
Silva, E; Martins, A; Dias, A; Matos, A; Olivier, A; Pinho, C; de Sa, FA; Ferreira, H; Silva, H; Alves, JC; Almeida, JM; Pessoa, L; Ricardo, M; Cruz, N; Dias, N; Monica, P; Jorge, P; Campos, R;
Publicação
OCEANS 2016 MTS/IEEE MONTEREY
Abstract
INESC TEC is strongly committed to become a center of excellence in maritime technology and, in particular, deep sea technology. The STRONGMAR project aims at creating solid and productive links in the global field of marine science and technology between INESC TEC and established leading research European institutions, capable of enhancing the scientific and technological capacity of INESC TEC and linked institutions, helping raising its staff's research profile and its recognition as a European maritime research center of excellence. The STRONGMAR project seeks complementarity to the TEC4SEA research infrastructure: on the one hand, TEC4SEA promotes the establishment of a unique infrastructure of research and technological development, and on the other, the STRONGMAR project intends to develop the scientific expertise of the research team of INESC TEC.
2017
Autores
Ricardo, Manuel; Campos, Rui; Ruela, Jose; Morla, Ricardo; Teixeira, Filipe; Pessoa, Luis; Salgado, Henrique;
Publicação
Wireless Days
Abstract
2015
Autores
Pinto, P; Pinto, A; Ricardo, M;
Publicação
IEEE SENSORS JOURNAL
Abstract
Real-time monitoring applications may be used in a wireless sensor network (WSN) and may generate packet flows with strict quality of service requirements in terms of delay, jitter, or packet loss. When strict delays are imposed from source to destination, the packets must be delivered at the destination within an end-to-end delay (EED) hard limit in order to be considered useful. Since the WSN nodes are scarce both in processing and energy resources, it is desirable that they only transport useful data, as this contributes to enhance the overall network performance and to improve energy efficiency. In this paper, we propose a novel cross-layer admission control (CLAC) mechanism to enhance the network performance and increase energy efficiency of a WSN, by avoiding the transmission of potentially useless packets. The CLAC mechanism uses an estimation technique to preview packets EED, and decides to forward a packet only if it is expected to meet the EED deadline defined by the application, dropping it otherwise. The results obtained show that CLAC enhances the network performance by increasing the useful packet delivery ratio in high network loads and improves the energy efficiency in every network load.
2014
Autores
Abreu, C; Miranda, F; Ricardo, M; Mendes, PM;
Publicação
SPRINGERPLUS
Abstract
Biomedical wireless sensor networks are a key technology to support the development of new applications and services targeting patient monitoring, in particular, regarding data collection for medical diagnosis and continuous health assessment. However, due to the critical nature of medical applications, such networks have to satisfy demanding quality of service requirements, while guaranteeing high levels of confidence and reliability. Such goals are influenced by several factors, where the network topology, the limited throughput, and the characteristics and dynamics of the surrounding environment are of major importance. Harsh environments, as hospital facilities, can compromise the radio frequency communications and, consequently, the network's ability to provide the quality of service required by medical applications. Furthermore, the impact of such environments on the network's performance is hard to manage due to its random and unpredictable nature. Consequently, network planning and management, in general or step-down hospital units, is a very hard task. In such context, this work presents a quality of service based management tool to help healthcare professionals supervising the network's performance and to assist them managing the admission of new sensor nodes (i.e., patients to be monitored) to the biomedical wireless sensor network. The proposed solution proves to be a valuable tool both, to detect and classify potential harmful variations in the quality of service provided by the network, avoiding its degradation to levels where the biomedical signs would be useless; and to manage the admission of new patients to the network.
2015
Autores
da Silva, PM; Dias, J; Ricardo, M;
Publicação
WIRELESS INTERNET (WICON 2014)
Abstract
Erasure codes have been employed in a wide range of applications to increase content availability, improve channel reliability, or to reduce downloading time. For several applications, such as P2P file sharing, MDS erasure codes are more suitable as the network is typically the most constrained resource, not the CPU. Rateless MDS erasure codes also enable to adjust encoding and decoding algorithms as function of dynamic variables to maximize erasure coding gains. State-of-the-art MDS erasure codes are either fixed-rate or have practical limitations. We propose Storm erasure codes, a rateless MDS construction of Reed-Solomon codes over the finite field F-p2, where p is a Mersenne prime. To the best of our knowledge, we are the first to propose a rateless construction (n can be increased in steps of k) with Theta (n log k) encoding time complexity and min {Theta(n log n), Theta(k log(2) k)} upper bound for decoding time complexity. We provide the complexity analysis of encoding and decoding algorithms and evaluate Storm's performance.
2015
Autores
da Silva, PM; Dias, J; Ricardo, M;
Publicação
Proceedings of the 8th International Conference on Simulation Tools and Techniques, Athens, Greece, August 24-26, 2015
Abstract
ns-3 is the successor of ns-2, the most popular network simulator. Network simulators such as ns-3 play an important role on understanding, designing, and building Internet systems. But simulations are only as good as their models, and the simulation of large scale Internet systems using accurate and complex models is a challenging task. ns-3 simulates realistically the network stack but the scale and complexity of the Internet topology is, from our point of view, limited by the IP forwarding operations. This work proposes CIDRarchy, an IPv4 routing protocol for ns-3 that uses CIDR as the base to create an hierarchical Internet-like network topology that enables (1) IP forwarding with constant time complexity and automatic IPv4 address assignment, and (2) the implementation of an ns-3 helper to ease network topology creation. We implemented CIDRarchy, evaluated its performance, and obtained simulation time reduction over existing ns-3 routing protocols implementations that can reach over one order of magnitude. Copyright © 2015 ICST.
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