Research and Technological Innovation Center

and Technological, Brazil

Research and Technological Innovation Center

and Technological, Brazil
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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.


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.


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.


Luiz D.F.,Federal University of Amazonas | Figueiredo C.M.S.,Research and Technological Innovation Center | Nakamura E.F.,Federal University of Amazonas | Nakamura E.F.,Research and Technological Innovation Center
Proceedings - IEEE Symposium on Computers and Communications | Year: 2012

Many applications in Wireless Sensor Networks (WSNs) consider remote and large scale monitoring. For those scenarios, the whole network is difficultly fully connected all the time. A possible vision is the union of WSNs and Disruptive Tolerant Network(DTNs) concepts, where mobile nodes make collect data in sparse networks and deliver them to a base station. This work presents a buffer management strategy, which is a basic principle in DTN networks. The proposed solution considers the global coverage to choose which messages are dropped, therefore, minimizing the impact on monitoring application. Such solutions are important for WSNs applications with limited resources. We show through simulation that the proposed Coverage-Based Drop-Policy in Wireless Sensor Network with Disruptive Connections (CBDP) improves the network coverage compared to traditional DTN drop policies like Drop Last Packet (DL) and Drop First Packet (DF). © 2012 IEEE.


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.


Campos A.N.,Federal University of Amazonas | Souza E.L.,Federal University of Amazonas | Nakamura F.G.,Federal University of Amazonas | Nakamura E.F.,Federal University of Amazonas | And 2 more authors.
Sensors (Switzerland) | Year: 2012

Target tracking is an important application of wireless sensor networks. The networks' ability to locate and track an object is directed linked to the nodes' ability to locate themselves. Consequently, localization systems are essential for target tracking applications. In addition, sensor networks are often deployed in remote or hostile environments. Therefore, density control algorithms are used to increase network lifetime while maintaining its sensing capabilities. In this work, we analyze the impact of localization algorithms (RPE and DPE) and density control algorithms (GAF, A3 and OGDC) on target tracking applications. We adapt the density control algorithms to address the k-coverage problem. In addition, we analyze the impact of network density, residual integration with density control, and k-coverage on both target tracking accuracy and network lifetime. Our results show that DPE is a better choice for target tracking applications than RPE. Moreover, among the evaluated density control algorithms, OGDC is the best option among the three. Although the choice of the density control algorithm has little impact on the tracking precision, OGDC outperforms GAF and A3 in terms of tracking time. © 2012 by the authors; licensee MDPI, Basel, Switzerland.


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.


Diaz J.J.M.,Research and Technological Innovation Center | De A. Maues R.,Research and Technological Innovation Center | Soares R.B.,Research and Technological Innovation Center | Nakamura E.F.,Research and Technological Innovation Center | Figueiredo C.M.S.,Research and Technological Innovation Center
Proceedings - IEEE Symposium on Computers and Communications | Year: 2010

Location-Based Services have become quite popular in mobile computing. However, these services are often not effective when devices are in indoor environments. This paper presents an indoor room-level Bluetooth-based localization system. Fixed stations distributed throughout the environment get the RSSI from user devices. With these data, we compute the distance between the device and the stations, based on the signal propagation. In this paper, we propose a room localization method, based on a voting scheme, that eliminates cells close to a base station detecting devices with a weak signal. Another contribution of this paper is the empirical evaluation of the methods within a real environment. © 2010 IEEE.


Machado K.,Federal University of Pará | Rosario D.D.,Federal University of Pará | Nakamura E.,Research and Technological Innovation Center | Abelem A.,Federal University of Pará | Cerqueira E.,Federal University of Pará
LANC 2011 - Proceedings of the 6th Latin America Networking Conference | Year: 2011

This paper sets out an extension of an AODV routing protocol, called Routing by Energy and Link quality indicator (REL). The proposed protocol adopts a new cross-layer approach as a mechanism to select the best routes. The paths are selected on the basis of remaining energy, a proposed link quality estimator (WeakLink), and hop count. Thus, REL provides reliability, energy-efficiency, and a fair distribution of network resources. © 2011 ACM.


PubMed | Research and Technological Innovation Center
Type: Journal Article | Journal: Sensors (Basel, Switzerland) | Year: 2012

Routing is a basic function in wireless sensor networks (WSNs). For these networks, routing algorithms depend on the characteristics of the applications and, consequently, there is no self-contained algorithm suitable for every case. In some scenarios, the network behavior (traffic load) may vary a lot, such as an event-driven application, favoring different algorithms at different instants. This work presents a hybrid and adaptive algorithm for routing in WSNs, called Multi-MAF, that adapts its behavior autonomously in response to the variation of network conditions. In particular, the proposed algorithm applies both reactive and proactive strategies for routing infrastructure creation, and uses an event-detection estimation model to change between the strategies and save energy. To show the advantages of the proposed approach, it is evaluated through simulations. Comparisons with independent reactive and proactive algorithms show improvements on energy consumption.

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