Encontrados 21 documentos, a visualizar página 1 de 3
Prototype WSN platform for performing dynamic monitoring of civil engineering s...
Aguilar, Rafael; Ramos, Luís F.; Lourenço, Paulo B.; Severino, Ricardo; Gomes, Ricardo; Gandra, Paulo; Alves, Mário; Tovar, EduardoStructural Health Monitoring represents the present and future of the civil engineering since, until few years ago, structural diagnosis works had been performed with few resources regarding to experimental techniques. Precisely in the field of monitoring sensors, the progress of new technologies based on wireless communications and Micro-Electro-Mechanical- Systems (MEMS) are of high interest for replacing the...
Order and chaos : interactive computational activities for the classroom
Severino, Ricardo; Torres, M. J.It has long been believed that typical students learn better through contemporary approaches to questions originated by physics problems that allow experiments. This belief motivated us to develop interactive computational didactic materials about contemporaneous mathematics that can be used both in the classroom and in mathematics clubs in school. Dynamical Systems, the study of how physical systems evolve wit...
Difference Equations and Nonlinear Boundary Value Problems for Hyperbolic Systems
Sharkovsky, Alexander; Severino, Ricardo; Vinagre, SandraIt is known that solutions of certain classes of linear hyperbolic systems with nonlinear boundary conditions and consistent initial conditions can be written via the iteration of a map of the interval. In this work we characterize the solutions of such problems, with a vortex as initial condition and the iteration of a bimodal map of the interval, using the bimodal topological invariants.
A traffic differentiation add-on to the IEEE 802.15.4 protocol: implementation ...
Severino, Ricardo; Batsa, Manish; Alves, Mário; Koubâa, AnisThe IEEE 802.15.4 is the most widespread used protocol for Wireless Sensor Networks (WSNs) and it is being used as a baseline for several higher layer protocols such as ZigBee, 6LoWPAN or WirelessHART. Its MAC (Medium Access Control) supports both contention-free (CFP, based on the reservation of guaranteed time-slots GTS) and contention based (CAP, ruled by CSMA/CA) access, when operating in beacon-enabled mod...
Dimensioning and worst-case analysis of cluster-tree sensor networks
Jurcik, Petr; Severino, Ricardo; Koubâa, Anis; Alves, Mário; Tovar, EduardoModeling the fundamental performance limits of Wireless Sensor Networks (WSNs) is of paramount importance to understand their behavior under the worst-case conditions and to make the appropriate design choices. This is particular relevant for time-sensitive WSN applications, where the timing behavior of the network protocols (message transmission must respect deadlines) impacts on the correct operation of these...
A wireless sensor network platform for structural health monitoring: enabling a...
Severino, Ricardo; Gomes, Ricardo; Alves, Mário; Sousa, Paulo; Tovar, Eduardo; Ramos, Luis; Aguilar, RafaelStructural health monitoring has long been identified as a prominent application of Wireless Sensor Networks (WSNs), as traditional wired-based solutions present some inherent limitations such as installation/maintenance cost, scalability and visual impact. Nevertheless, there is a lack of ready-to-use and off-the-shelf WSN technologies that are able to fulfill some most demanding requirements of these applicat...
Kneading curves for Lozi maps
Baptista, Diogo; Severino, Ricardo; Vinagre, SandraWe explore some analogy between unimodal tent maps of the interval and Lozi maps, defining the critical point and the kneading sequence of a Lozi map. Then, we show that the set of parameter plane curves corresponding to Lozi maps with some initial kneading sequence has a structure close to the tree of unimodal tent kneading sequences, introduced by Sousa Ramos.
The basin of attraction of Lozi mappings
Baptista, Diogo; Severino, Ricardo; Vinagre, SandraFor parameter values which assure its existence, we characterize the basin of attraction for the Lozi map strange attractor.
Quality-of-service in wireless sensor networks: state-of-the-art and future dir...
Alves, Mário; Baccour, Nouha; Koubâa, Anis; Severino, Ricardo; Dini, Gianluca; Pereira, Nuno; Sá, Rui; Savino, Ida; Sousa, Paulo Gandra deWireless sensor networks (WSNs) are one of today’s most prominent instantiations of the ubiquituous computing paradigm. In order to achieve high levels of integration, WSNs need to be conceived considering requirements beyond the mere system’s functionality. While Quality-of-Service (QoS) is traditionally associated with bit/data rate, network throughput, message delay and bit/packet error rate, we believe that...
Operational modal monitoring of ancient structures using wireless technology
Aguilar, Rafael; Ramos, Luis; Lourenço, Paulo; Severino, Ricardo; Gomes, Ricardo; Sousa, Paulo Gandra de; Alves, Mário; Tovar, EduardoOperational Modal Analysis is currently applied in structural dynamic monitoring studies using conventional wired based sensors and data acquisition platforms. This approach, however, becomes inadequate in cases where the tests are performed in ancient structures with esthetic concerns or in others, where the use of wires greatly impacts the monitoring system cost and creates difficulties in the maintenance and...
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