Juan R. Diaz

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.

Noninvasive ventilatory assistance during exercise for patients with kyphoscoliosis : A pilot study

Vila B, Servera E, Marín J, Díaz J, Giménez M, Komaroff E, Bach J: Noninvasive ventilatory assistance during exercise for patients with kyphoscoliosis: a pilot study. Am J Phys Med Rehabil 2007;86:672–677. The goal was to determine whether noninvasive ventilatory assistance (NIV) could facilitate exercise performance and benefit physiologic parameters for eight hypercapnic kyphoscoliosis patients using a cycloergometer for 6-min periods at a constant power (20 W). The exercise protocols were performed in random order while breathing unaided (spontaneous breathing test or SBT) and also while receiving NIV (NIV test or NIVT). The NIV was pressure support (15 cm H2O) plus positive end expiratory pressure (PEEP) (4 cm H2O) via a nasal mask. Of the compared parameters, heart rate was not significantly different, but acidosis (pH = 7.32 ± 0.04 vs. 7.36 ± 0.04), hypoxia (PaO2 = 61.5 ± 15.9 vs. 69.5 ± 15.7 mm Hg), and hypercapnia (PaCO2 = 54.3 ± 7.6 vs. 47.1 ± 7.1 mm Hg) were significantly greater for the SBT than for the NIVT (P < 0.05). The hypercapnia and hypoxia for the NIVT were not significantly greater than preexercise resting levels. Dyspnea and perceived effort were significantly greater for the SBT (P < 0.05). In conclusion, NIV can improve clinical and physiologic response to exercise.

Communication Ad Hoc Protocol for Intelligent Video Sensing Using AR Drones

In order to use intelligent video sensing systems, three main features should be satisfied. HD video transmission to provide enough video quality for image treatment, a wireless ad hoc network to intelligent locate and focus the issue to be sensed and enough available bandwidth to provide HD video quality. This paper presents a communication protocol designed and deployed to provide HD video transfers between several mobile devices working with Android and Linux OS. Experimental results using AR Drones with Wi-Fi forming an ad hoc network demonstrate the big potential of this kind of networks in mobile devices. The use of AR Drones will revolution the field of HD video communications over air for intelligent video sensing because they have many sensors to be controlled autonomously using GPS or manually using remote control.

A Smart M2M Deployment to Control the Agriculture Irrigation

Wireless sensor networks (WSN) have become in a very powerful infrastructure to manage all kind of services. They provide the mechanism to control a big number of devices distributed around a big geographical space. The implementation of a sensor network is cheap and fast and it allows us to add a smart layer over the physical topology. For these reasons, they have begun to be used in many applications and environments. In this paper, we propose a new smart M2M system based on wireless sensor network to manage and control irrigation sprinklers. Humidity and temperature of soil are used to extract information about soil conditions. The network protocol builds an ad hoc infrastructure to exchange the information over the whole WSN. The proposed algorithm uses the meteorological parameters and characteristics of soil to decide which irrigation sprinklers have to be enabled and when we have to do it. Using our intelligent system we can reduce irrigation water consumption, avoiding activation of sprinklers when they are not needed.

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.

A QoS-Based Wireless Multimedia Sensor Cluster Protocol

Wireless Sensor Networks (WSNs) provide a wireless network infrastructure for sensed data transport in environments where wired or satellite technologies cannot be used. Because the embedded hardware of the sensor nodes has been improved very much in the last years and the number of real deployments is increasing considerably, they have become a reliable option for the transmission of any type of sensed data, from few sensed measures to multimedia data. This paper proposes a new protocol that uses an ad hoc cluster based architecture which is able to adapt the logical sensor network topology to the delivered multimedia stream features, guaranteeing the quality of the communications. The proposed protocol uses the quality of service (QoS) parameters, such as bandwidth, delay, jitter, and packet loss, of each type of multimedia stream as a basis for the sensor clusters creation and organization inside the WSN, providing end-to-end QoS for each multimedia stream. We present real experiments that show the performance of the protocol for several video and audio cases when it is running.

An architecture to connect disjoint multimedia networks based on node's capacity

TCP/IP protocol suite allows building multimedia networks of nodes according to nodes’ content sharing. Some of them have different types of protocols (some examples given in unstructured P2P file-sharing networks are Gnutella 2, FastTrack, OpenNap, eDonkey and so on). This paper proposes a new protocol to connect disjoint multimedia networks using the same resource or content sharing to allow multimedia content distribution. We show how nodes connect with nodes from other multimedia networks based on nodes’ capacity. The system is scalable and fault-tolerant. The designed protocol, its mathematical model, the messages developed and their bandwidth cost are described. The architecture has been developed to be applied in multiple types of multimedia networks (P2P file-sharing, CDNs and so on). We have developed a general-purpose application tool with all designed features. Results show the number of octets, the number of messages and the number of broadcasts sent through the network when the protocol is running.

A new multimedia-oriented architecture and protocol for wireless ad hoc networks

The number of smart phones, tablets, PDAs and other type of mobile devices used regularly by the population is growing fast. They are able to offer high processing capacities while having several wireless interfaces. Wireless ad hoc networks are currently widely used to share resources between users. In this paper, we propose a new multimedia-oriented application layer protocol. It takes into account the multimedia services offered by the nodes in the wireless ad hoc network to select the best multimedia service provider node and to provide the best QoE and quality of service QoS to the nodes participating in the ad hoc network. We will explain the designed protocol and decision algorithms to provide the best multimedia service to the end users. Then, we will show a study case and we will validate our proposed system through the measurements taken from a real test bench. There is no protocol designed such as the one presented in this paper.

802.11g WLANs Design for Rural Environments Video-surveillance

There is a lot of literature where researches show the best way to develop WLANs inside buildings. Their approaches try to provide large coverage and high performance taking into account wall looses and other issues. WLAN outdoor deployments are usually used to provide Internet access for citizens. In this article we show all parameters taken into account and the measurements taken to develop a new type of WLANs: WLAN for rural environments video-surveillance. These types of wireless networks are usually covered by other wireless frequencies, not by 802.11g. First we will start from the election of the MPEG-4 codec that will be used for transmission. It will be chosen as a function of the devices used in the deployment. Second, we will show the issues of a rural environment design and the wireless coverage area mathematical design. We will take into account signal looses given in rural environments. Finally we will show the number of octets per second, the number of messages per second and the network utilization in % measured from a public natural park deployment

Deployment and Performance Study of an Ad Hoc Network Protocol for Intelligent Video Sensing in Precision Agriculture

Recent advances in technology applied to agriculture have made possible the Precision Agriculture (PA). It has been widely demonstrated that precision agriculture provides higher productivity with lower costs. The goal of this paper is to show the deployment of a real-time precision sprayer which uses video sensing captured by lightweight UAVs (unmanned aerial vehicles) forming ad hoc network. It is based on a geo-reference system that takes into account weeds inside of a mapped area. The ad hoc network includes devices such as AR Drones, a laptop and a sprayer in a tractor. The experiment was carried out in a corn field with different locations selected to represent the diverse densities of weeds that can be found in the field. The deployed system allows saving high percentage of herbicide, reducing the cost spent in fertilizers and increasing the quality of the product.