Diana Bri

A Wireless Sensor Network Deployment for Rural and Forest Fire Detection and Verification

Forest and rural fires are one of the main causes of environmental degradation in Mediterranean countries. Existing fire detection systems only focus on detection, but not on the verification of the fire. However, almost all of them are just simulations, and very few implementations can be found. Besides, the systems in the literature lack scalability. In this paper we show all the steps followed to perform the design, research and development of a wireless multisensor network which mixes sensors with IP cameras in a wireless network in order to detect and verify fire in rural and forest areas of Spain. We have studied how many cameras, sensors and access points are needed to cover a rural or forest area, and the scalability of the system. We have developed a multisensor and when it detects a fire, it sends a sensor alarm through the wireless network to a central server. The central server selects the closest wireless cameras to the multisensor, based on a software application, which are rotated to the sensor that raised the alarm, and sends them a message in order to receive real-time images from the zone. The camera lets the fire fighters corroborate the existence of a fire and avoid false alarms. In this paper, we show the test performance given by a test bench formed by four wireless IP cameras in several situations and the energy consumed when they are transmitting. Moreover, we study the energy consumed by each device when the system is set up. The wireless sensor network could be connected to Internet through a gateway and the images of the cameras could be seen from any part of the world.

Real Deployments of Wireless Sensor Networks

Sensor networks are becoming one of the most used technologies in our lives. Although there are several surveys about sensor networks, almost all of them focus on theoretical basis with little simulations. Some of the studies only explain where these kinds of networks can be useful, without details on how can they be applied. This paper classifies the applications of wireless sensor networks and describes real implementations. The target is to complement the existing surveys, by presenting details on real implementations in order to understand how these networks run, and how they are designed, maintained and operated.

A Cluster-Based Architecture to Structure the Topology of Parallel Wireless Sensor Networks

A wireless sensor network is a self-configuring network of mobile nodes connected by wireless links where the nodes have limited capacity and energy. In many cases, the application environment requires the design of an exclusive network topology for a particular case. Cluster-based network developments and proposals in existence have been designed to build a network for just one type of node, where all nodes can communicate with any other nodes in their coverage area. Let us suppose a set of clusters of sensor nodes where each cluster is formed by different types of nodes (e.g., they could be classified by the sensed parameter using different transmitting interfaces, by the node profile or by the type of device: laptops, PDAs, sensor etc.) and exclusive networks, as virtual networks, are needed with the same type of sensed data, or the same type of devices, or even the same type of profiles. In this paper, we propose an algorithm that is able to structure the topology of different wireless sensor networks to coexist in the same environment. It allows control and management of the topology of each network. The architecture operation and the protocol messages will be described. Measurements from a real test-bench will show that the designed protocol has low bandwidth consumption and also demonstrates the viability and the scalability of the proposed architecture. Our ccluster-based algorithm is compared with other algorithms reported in the literature in terms of architecture and protocol measurements.

Using MANET Protocols in Wireless Sensor and Actor Networks

Although there are several routing protocols for wireless sensor and actor networks (WSAN), none of them have became standard. Now, there are several standard protocols for mobile ad hoc networks (MANET) that have been developed for devices with higher computing features than the sensor nodes. On the other hand, one of the main characteristics of the MANET protocols is their scalability. In this paper, we show the performance of a WSAN, when MANET protocols are used, for several topologies. We will discuss and evaluate which standard protocol is the best one depending on the number of nodes in the topology and depending on their mobility. Finally we will show their comparison. As far as we know, there is not any performance comparison of MANET protocols such as the one presented in this paper.

Vertical WLAN handover algorithm and protocol to improve the IPTV QoS of the end user

The appearance of several IEEE 802.11 variants made possible the availability of many wireless local area network access options for end users in the same location. Network requirements for IPTV service become higher when the quality of the delivered video is higher. Moreover, in wireless networks the network performance is highly degraded when there is high number of users. In this paper, we propose a protocol and algorithm that makes to handover IPTV users to the best available WLAN when the QoS parameters received by the end user reaches a threshold. It guarantees anytime the highest QoS for the user. Real measurements show that the vertical handover performed by the user is performed without noticing it. This algorithm is highly appropriate for mobile users.

How the Weather Impacts on the Performance of an Outdoor WLAN

It is believed that meteorological factors such as rain, wind or temperature do not affect significantly to wireless systems operating at radio frequencies below 10 GHz. However, using an appropriate statistical analysis to the measurements taken from an outdoor IEEE 802.11b/g WLAN, we show that this is not true. Although these networks operate at 2.4 GHz, we have been able to prove a significant relationship between some meteorological factors and the behavior of several control frames in these networks.

Study and performance of a group-based Content Delivery Network

It is known that a group-based system provides better performance and more scalability to the whole system while it decreases the communication traffic. Group-based architectures in Content Delivery Networks (CDNs) could be a good solution to the need of scalability or when the bandwidth is a limitation. There is no pure group-based CDN in existence, although we proposed a group-based system to interconnect CDNs of different providers in a previous work. This article shows a new Content Delivery Network based on grouping surrogates. We will show the benefits of our proposal and its application environment. We will describe the protocol developed to connect surrogates from the same group and from different groups. The neighbor selection algorithm is based on their distance and Round Trip Delay in order to provide lower content distribution times. The system improves the Quality of Service (QoS) by connecting surrogates with higher available capacity. Real measurements of the network control traffic and of the performance of the surrogates in a controlled environment are shown. We will also demonstrate its scalability by comparing the control traffic for different numbers of surrogates in the CDN. Finally we will show the differences with the system proposed in our previous work.

How the Atmospheric Variables Affect to the WLAN Datalink Layer Parameters

There are many issues that affect to WLAN connections (walls, vegetation, rain, objects in the Fresnel zone, etc.). Network designers and telecommunication practitioners must take them into account when they are planning wireless connections between devices. Some studies have demonstrated the implication of the atmospheric variables in the frequency attenuation and in the line of sight of the waves. But, to the extend of our knowledge, there is not any work published that relates the atmospheric variables with the datalink layer parameters of the WLANs. We must take into account that the datalink layer allows us to measure quite more parameters than the physical layer. After a review of the published related works, first, we will show the atmospheric variables measured during two months, and, then we will show the datalink layer parameters that we have been able to measure during those months. Finally, we will discuss the implications of the atmospheric variables in the measured parameters and we will estimate the laws followed by our measurements.

A content distribution network deployment over WLANs for fire detection in rural environments

In the recent years, there have been published many works about content distribution schemes and algorithms, but most of them have not got beyond the planning stage, while others are complemented only by some simulations. This paper shows a real deployment of a wireless network which distributes the information in a different manner based on the type of content delivered (video steaming, sensor information or sensor alarms). On the other hand, the system has multiple video and sensor sources and two types of users: the regular users and the firefighters. P2P connections are established between video stream sources and the end users. The aim of the network is to detect and monitor any fire in rural and forest environments while it is being used to show the rural area to the visitors. We will show our network design taking into account the type of content and the application environment. Then, we will show the measurements we made to take the election of the codec to use for the video streaming. Finally, on one hand we will show the end user and firefighter interface, and on the other hand, the measurements and their analysis we made to test the performance of the network.

A Multisensor Proposal for Wireless Sensor Networks

Every sensor node in a wireless sensor network (WSN) has a microcontroller, a transmitter/receiver and a sensor. It is able to acquire data from specific point in a real environment and transmit it through the WSN. Sometimes it is useful to gather different type of data from the same place in order to obtain a final result. In the related literature, very few works are about sensing different parameters using a unique sensor. In this paper we propose a Wireless IP multisensor that is able to gather several types of data from the environment and transmit the result of their combination. Our proposal decision has being mainly based on its development costs, its expansion capacity and its flexibility to add more features to the sensor node. We will show all the characteristics of our proposal and its application areas. A comparison with other wireless IP sensors will be also provided.