Entity

Time filter

Source Type


Da Penha Jr. O.S.,Federal University of Amazonas | Nakamura E.F.,Research and Technological Innovation Center
Proceedings - IEEE Symposium on Computers and Communications | Year: 2010

Wireless Sensor Networks (WSN) are often designed to detect events based on measurements provided by sensor nodes. In this work, we propose and evaluate two algorithms, based on information fusion methods, for fire detection in rainforests when we have only light and temperature sensors. The idea is to have acceptable detection methods even when we do not have (or cannot afford) other sensor units that would lead to more accurate inferences, such as humidity sensors, smoke detectors or video cameras. In this sense, we collect and analyze real environmental data in situations that are similar to those found in real scenarios. Then, we create some controlled fire (events) of small proportion, close to sensor nodes, to force event occurrences. Experimental results indicate that forest fire can be detected at night by using just light measurements. In addition, light data can be used to distinguish heat resulting from sunbeam and fire. The first method is based on the moving average filter and thresholds (Threshold method), while the second uses the moving average filter and the Dempster-Shafer theory. Both methods present similar results regarding the detection efficacy considering the generated instances. However, the Threshold method is more stable, due to the use of state machine to represent the environment conditions.© 2010 IEEE. Source


Da Silva Campos B.,Federal University of Amazonas | Da Silva Campos B.,University of Beira Interior | Nakamura E.F.,Research and Technological Innovation Center | Figueiredo C.M.S.,Research and Technological Innovation Center | Rodrigues J.J.P.C.,University of Beira Interior
Proceedings - IEEE Symposium on Computers and Communications | Year: 2011

In this paper, it is presented the design of a Universal Plug and Play (UPnP) gateway for wireless sensor networks (WSNs), capable of discovering all the services of a WSN, and creating a unique UPnP device to advertise them to interested UPnP control points. Besides, an application protocol for WSN is designed to exchange UPnP-related data between the WSN and the gateway. Experiments in an indoor environment with restricted sensor nodes confirm the feasibility of this solution. © 2011 IEEE. Source


Nakamura E.F.,Research and Technological Innovation Center | Souza E.L.,Federal University of Amazonas
Proceedings - IEEE Symposium on Computers and Communications | Year: 2010

The majority of event-based solutions for wireless sensor networks (WSNs) are evaluated considering a given event-detection model, such as a fixed radius. Such models are used to validate algorithms for different problems in WSNs, such as coverage, routing, density control, and target tracking. However, current models are not suitable for every scenario. Usually, the detection efficacy depends on several factors, such as environmental conditions, sensor reliability, measurement methods, and event characteristics. In this work, we propose a probabilistic detection-model that aims at modeling different scenarios, and can be configured to properly approximate other detection models adopted in WSNs. We simulate the detection capability of our model in comparison to the popular fixed radius. © 2010 IEEE 459. Source


Oliveira H.A.B.F.,Federal University of Amazonas | Barreto R.S.,Federal University of Amazonas | Fontao A.L.,Federal University of Amazonas | Loureiro A.A.F.,Federal University of Minas Gerais | Nakamura E.F.,Research and Technological Innovation Center
Proceedings - International Conference on Computer Communications and Networks, ICCCN | Year: 2010

Sink nodes are responsible for aggregating data gathered by a Wireless Sensor Network (WSN) and transmitting them to a monitoring facility. Usually, these are static nodes that serve as gateways to infrastructured networks. In some applications, these sink nodes move around the monitoring area, usually in lower speeds (e.g., robots, dirigibles). In this work, we go further and study WSN scenarios in which sink nodes can move at higher speeds, such as an Unmanned Aerial Vehicle (UAV) or even an airplane. In these cases, propagated queries cannot be answered by using the sink's position when the query was sent, since the sink will be elsewhere due to its high speed. Thus, we propose and evaluate the performance of three algorithms for data query in WSNs when the sink is moving at a high speed. Our results show clearly the need for new algorithms for these scenarios as well as the good performance of our proposed algorithms. © 2010 IEEE. Source


Onety R.E.,Federal University of Minas Gerais | Onety R.E.,Polytechnic University of Turin | Onety R.E.,Research and Technological Innovation Center | Tadei R.,Polytechnic University of Turin | And 2 more authors.
Applied Soft Computing Journal | Year: 2013

This paper presents a Genetic Algorithm for the optimization of multiple indices of Quality of Service of Multi Protocol Label Switching (MPLS) IP networks. The proposed algorithm, the Variable Neighborhood Multiobjective Genetic Algorithm (VN-MGA), is a Genetic Algorithm based on the NSGA-II, with the particular feature that solutions are encoded defining two different kinds of neighborhoods. The first neighborhood is defined by considering as decision variables the edges that form the routes to be followed by each request, whilst the second part of solution is kept constant. The second neighborhood is defined by considering the request sequence as decision variable, with the first part kept constant. Comparisons are performed with: (i) a VNS algorithm that performs a switch between the same two neighborhoods that are used in VN-MGA; and (ii) the results obtained with an integer linear programming solver, running a scalarized version of the multiobjective problem. The results indicate that the proposed VN-MGA outperforms the pure VNS algorithm, and provides a good approximation of the exact Pareto fronts obtained with Integer Linear Programming (ILP) approach, at a much smaller computational cost. Besides potential benefits of the application of the proposed approach to the optimization of packet routing in MPLS networks, this work raises the theoretical issue of the systematic application of variable encodings, which allow variable neighborhood searches, as generic operators inside general evolutionary computation algorithms. © 2012 Elsevier B.V. All rights reserved. Source

Discover hidden collaborations