Pawel Kulakowski

Technical Communication: Angle-of-arrival localization based on antenna arrays for wireless sensor networks

Among the large number of contributions concerning the localization techniques for wireless sensor networks (WSNs), there is still no simple, energy and cost efficient solution suitable in outdoor scenarios. In this paper, a technique based on antenna arrays and angle-of-arrival (AoA) measurements is carefully discussed. While the AoA algorithms are rarely considered for WSNs due to the large dimensions of directional antennas, some system configurations are investigated that can be easily incorporated in pocket-size wireless devices. A heuristic weighting function that enables decreasing the location errors is introduced. Also, the detailed performance analysis of the presented system is provided. The localization accuracy is validated through realistic Monte-Carlo simulations that take into account the specificity of propagation conditions in WSNs as well as the radio noise effects. Finally, trade-offs between the accuracy, localization time and the number of anchors in a network are addressed.

Wireless Sensor Network Deployment for Monitoring Wildlife Passages

Wireless Sensor Networks (WSNs) are being deployed in very diverse application scenarios, including rural and forest environments. In these particular contexts, specimen protection and conservation is a challenge, especially in natural reserves, dangerous locations or hot spots of these reserves (i.e., roads, railways, and other civil infrastructures). This paper proposes and studies a WSN based system for generic target (animal) tracking in the surrounding area of wildlife passages built to establish safe ways for animals to cross transportation infrastructures. In addition, it allows target identification through the use of video sensors connected to strategically deployed nodes. This deployment is designed on the basis of the IEEE 802.15.4 standard, but it increases the lifetime of the nodes through an appropriate scheduling. The system has been evaluated for the particular scenario of wildlife monitoring in passages across roads. For this purpose, different schemes have been simulated in order to find the most appropriate network operational parameters. Moreover, a novel prototype, provided with motion detector sensors, has also been developed and its design feasibility demonstrated. Original software modules providing new functionalities have been implemented and included in this prototype. Finally, main performance evaluation results of the whole system are presented and discussed in depth.

Performance study of wireless sensor and actuator networks in forest fire scenarios

SUMMARY Wireless sensor and actuator networks (WSANs) for environmental disaster scenarios are considered in this paper. A fully independent and autonomous WSAN system that is able to detect and extinguish a fire in a burning wildland area is proposed. Although forest fire detection is a classical application for sensor networks, in this paper, this research area is extended, taking into account actuators and their ability to put out fire in the presence of measurement inaccuracy and network degradation. A system architecture is proposed, modelled and discussed. An extensive set of computer simulations analysing the system performance is reported. The presented results show the efficiency of fire-fighting actions depending on the sensors’ density and the actuators’ mobility. Copyright

Sensors-actuators cooperation in WSANs for fire-fighting applications

Wireless sensor and actuator networks for environmental operations are discussed in this paper. A scenario of a forest being under fire is analyzed. While the forest fire detection is a classical application for sensor networks, here this research area is extended, taking into account actuators and focusing on sensors-actuators cooperation. First, the spreading of the fire is illustrated, adapting a well-known model based on percolation theory and explaining its relations with epidemics propagation models. Then, it is shown how the temperature data gathered by sensors can be used by actuators to automatically perform actions to battle with blaze. Finally, the simulation results are presented, documenting the correctness of the decisions taken by the system and the efficiency of fire-fighting actions related to the sensors density.

Measurements on MIMO-FRET Nano-Networks Based on Alexa Fluor Dyes

Nanocommunication has gained significant attention in the last few years, as a means to establish information transfer between future nanomachines. Comparing with other communication techniques for nanoscale (calcium ions signaling, molecular or catalytic nanomotors, pheromones propagation, bacteria-based communication), the phenomenon called Förster Resonance Energy Transfer (FRET) offers significantly smaller propagation delays and high channel throughput. In this paper, we report our recent experiments on FRET-based nanonetworks performed in the Laboratory of Cell Biophysics of the Jagiellonian University, Kraków. We propose to use Alexa Fluor dyes as nano transmitters and receivers, as they enable to create multiple-input multioutput (MIMO) FRET communication channels and thus enhance FRET efficiency. We measure FRET efficiency values, calculate bit error rates for the measured scenarios, and extend the calculations to consider a general case of MIMO (n, m) FRET channels.

A convex hull-based approximation of forest fire shape with distributed wireless sensor networks

Monitoring of physical phenomena is one of the most promising application fields of wireless sensor networks. In this work we focus on obtaining the shape of a forest fire. In this kind of applications, the information sensed by network nodes is usually transmitted to a base station located at the border of the network, where it is finally processed. However, such an approach requires that a large amount of data is transmitted through the network. In this paper, we assume that network nodes are able to collaborate in order to obtain an approximation of the forest fire shape without any base station, in a completely distributed way. We propose and analyze two techniques for performing this approximation. The first one makes intensive use of resources, while the second model incorporates an aggregation technique, reducing significantly resource requirements.

Nanocommunication via FRET With DyLight Dyes Using Multiple Donors and Acceptors

The phenomenon of Förster Resonance Energy Transfer, commonly used to measure the distances between fluorophore molecules and to study interactions between fluorescent-tagged proteins in life sciences, can also be applied in nanocommunication networks to transfer information bits. The mechanism offers a relatively large throughput and very small delays, but at the same time the channel bit error rate is too high and the transmission ranges are too limited for communication purposes. In this paper, multiple donors at the transmitter side and multiple acceptors at the receiver side are considered to decrease the bit error rate. As nanoantennas, the DyLight fluorescent dyes, which are very well suited to long range nanocommunication due to their large Förster distances and high degrees of labeling, are proposed. The reported results of the recent laboratory experiments confirm efficient communication on distances over 10 nm.

Routing in FRET-Based Nanonetworks

Nanocommunications, understood as communications between nanoscale devices, is commonly regarded as a technology essential for cooperation of large groups of nanomachines and thus crucial for development of the whole area of nanotechnology. While solutions for pointto- point nanocommunications have already been proposed, larger networks cannot function properly without routing. In this article we focus on nanocommunications via FRET, which was found to be a technique with a very high signal propagation speed, and discuss how to route signals through nanonetworks. We introduce five new routing mechanisms, based on biological properties of specific molecules. We experimentally validate one of these mechanisms. Finally, we analyze open issues showing the technical challenges for signal transmission and routing in FRET-based nanocommunications.

ARROW: Azimuth-Range ROuting for large-scale Wireless sensor networks

During the past few years, the development of wireless sensor network technologies has spurred the design of novel protocol paradigms capable of meeting the needs of a wide broad of applications while taking into account the inherent constraints of the underlying network technologies, e.g. limited energy and computational capacities. Geographic routing is one of such paradigms whose principles of operation are based on the geographic location of the network nodes. Even though the large number of works already reported in the literature, there are still many open issues towards the design of robust and scalable geographic routing algorithms. In this study, after an analysis of the most relevant solutions reported in the literature, we introduce Azimuth-Range ROuting for large-scale Wireless (ARROW) sensor networks. ARROW goes a step further on the design of geographic routing protocols by defining a simple and robust routing protocol whose operation principles completely free the network nodes of the burden of keeping routing records. Under ARROW, nodes carry out all routing decisions exclusively using the information imbedded in the data packets while avoiding the risk of routing loops, a major challenge when designing routing protocols for large-scale networks. Moreover, ARROW is supplemented with a simple yet effective forwarder resolution protocol, also introduced in this study, allowing the fast and loop-free selection of the forwarding node in a hop-to-hop basis. Both protocols, ARROW and the proposed forwarder resolution protocol, are validated by extensive computer simulations. Our results show that both protocols exhibit excellent scalability properties by limiting the overhead.

Limited resources in ambient systems for disaster scenarios

We describe a concept of autonomous intelligent and ambient networks suited for disaster scenarios (e.g. pollution leakages, earthquakes or forest fires) where the decisions are made only on the basis of sensed data, without human control. We discuss possible system architectures: its passive component (sensors) that monitors the environment, as well as the active one, i.e. robots or other machines (actuators) that are able to react accordingly to the previously gathered data. We highlight some challenges regarding distributed and self-organizational aspects of these networks. Also, we address an issue of collaboration that should exist between sensors and actuators. The decisions about the actuator operations are made based on previously sensed data, but these operations can also improve the quality of information gathered later. As an example, we present a simulated scenario of a network able to detect and cease a wildland fire. It is shown how the network performance depends on its limited resources and how sensors readings and actuators actions depend on each other.