Andrea Seraghiti

Self-adapting maximum flow routing for autonomous wireless sensor networks

Autonomous wireless sensor networks are subject to power, bandwidth, and resource limitations that can be represented as capacity constraints imposed to their equivalent flow networks. The maximum sustainable workload (i.e., the maximum data flow from the sensor nodes to the collection point which is compatible with the capacity constraints) is the maxflow of the flow network. Although a large number of energy-aware routing algorithms for ad-hoc networks have been proposed, they usually aim at maximizing the lifetime of the network rather than the steady-state sustainability of the workload. Energy harvesting techniques, providing renewable supply to sensor nodes, prompt for a paradigm shift from energy-constrained lifetime optimization to power-constrained workload optimization.This paper presents a self-adapting maximum flow (SAMF) routing strategy which is able to route any sustainable workload while automatically adapting to time-varying operating conditions. The theoretical properties of SAMF routing are formally proved and a simulation model is developed on top of OMNeT++ (http://www.omnetpp.org/) in order to enable simulation-based assessment and design exploration. Simulation results are reported which demonstrate the applicability of the proposed approach.

Filtering obfuscated email spam by means of phonetic string matching

Rule-based email filters mainly rely on the occurrence of critical words to classify spam messages. However, perceptive obfuscation techniques can be used to elude exact pattern matching. In this paper we propose a new technique for filtering obfuscated email spam that performs approximate pattern matching both on the original message and on its phonetic transcription.

Self-Adapating Maxflow Routing for Autonomous Wireless Sensor Networks

Energy-harvesting wireless sensor networks (EHWSNs) can be modeled as flow networks with channel capacities limited by the ratio between the environmental power available at the nodes and the energy they need to process each packet.The maximum workload that can be sustained by environmental power is the maxflow that can be routed across the network from sensor nodes to the sink.This paper presents a theoretically-optimum maxflow routing algorithm that makes EH-WSNs able to transparently adapt to time-varying environmental power conditions during their normal operation.

Multicast TV Channels over Wireless Neutral Access Networks

IP Television (IPTV) is commonly considered to be the killer application for next-generation networks (NGNs). There is, however, a chicken and egg situation between the deployment of broadband access networks and the diffusion of high quality multimedia services, such as high definition television, which actually impairs the development of NGNs. As a matter of fact, most existing access infrastructures are still under-provisioned and they provide no suitable support to the widespread diffusion of global Internet TV channels, while wireless access networks are sprouting worldwide to provide nomadic connectivity and to bridge digital divide in sparsely populated regions. In this scenario, IPTV services are delivered only within the walled gardens of biggest wireline operators and they are far away from reaching the critical mass required to attract investments in NGNs. This paper proposes technological and architectural solutions which enable the widespread diffusion of Internet TV channels over existing wireless access networks, thus overcoming the deadlock between services and infrastructures and paving the way to NGNs. In particular, the paper addresses both technological and market issues and presents the results of a real-world experiment conducted within the wireless campus of the University of Urbino.

Demo: Mobile Crowdsensing of Road Surface Roughness

The roughness of the road surface affects driving safety and comfort. Having complete and up to date information on the state of the road network is essential for maintenance planning, but it entails time consuming and costly monitoring activities. As a matter of fact, maintenance interventions are mainly based on the results of case by case inspections prompted by drivers’ reports. Moreover, qualitative observations are seldom supported by objective measures, making it difficult for administrators to collect data providing a clear perception of the actual priorities. Recent studies have shown that it is possible to exploit the triaxial accelerometers with which smartphones are equipped to obtain a sound indicator of road surface roughness [1, 2]. A crowdsensing system, called SmartRoadSense [3], has been developed to allow any driver to contribute with his/her smartphone in monitoring the status of the roads he/she travels by car. As shown in Fig. 1, Smartroadsense is composed of: a mobile application, a cloud-based backend, and a web portal. The application runs in background on any car-mounted Android smartphone, reads the accelerometer data at a fre-

Neutral Access Network Implementation Based on Linux Policy Routing

Neutral access networks (NANs) have been proposed as a mean for overcoming the stagnation of broadband market by granting positive externality to access infrastructures, in order to trigger a virtuous circle among investors, network operators, users, and service providers. From a technical point of view, NANs prompt for the development of new solutions to design and implement a shared infrastructure which enables unregistered users to associate to the network, to take advantage of local services delivered within the access network, and to register seamlessly with the Internet service provider of choice to gain instantaneous access to the Internet. This paper presents a NAN implementation, based on Linux policy routing, which has been developed and tested within the wireless campus of the University of Urbino.

Self-adapting maxflow routing algorithm for WSNs: practical issues and simulation-based assessment

Autonomous wireless sensor networks are subject to power, bandwidth, and resource limitations that can be represented as capacity constraints imposed to their equivalent flow networks. The maximum sustainable workload of a sensor net work (i.e., the maximum data flow from the sensor nodes to the collection point which is compatible with the capacity constraints) is the maxflow of the flow network. This paper presents a self-adapting maxflow routing algorithm which is able to route any sustainable workload while automatically adapting to time-varying operating conditions. The algorithm has been implemented on top of OMNeT++ [1] in order to address practical issues and to enable simulation-based assessment and design exploration Simulation results demonstrate the effectiveness and the applicability of the proposed approach

Exploiting ultra-low-power ultrasonic wake-up triggering for sensor nodes distance measurements

Out-of-band signaling provides a valuable support to the management of wireless sensor networks. Among other signals, sound has a propagation speed in air which is fast enough to be neglected in typical sensor network applications, and slow enough to be measured by means of low-cost embedded systems. An ultrasonic triggering mechanism has been recently developed for VirtualSense, an ultra-low-power sensor node featuring a Java runtime environment. Ultrasonic triggers provide on-demand wakeup capabilities that can be exploited by routing nodes to be switched on whenever there is a packet to be routed towards the sink, while spending all the idle time in an ultra low power inactive state where even the radio module is turned off. In addition, the same hardware components can be used to perform pairwise distance measurements that can be exploited for localization. In this demonstration we show the possible use of VirtualSense ultrasonic wake-up modules as distance estimators.

User-Provided Wireless Neutral Access Networks

Involving end-users in the creation of an overlay wireless access network, which provides nomadic connectivity by exploiting under-utilized residential connections, is an attractive perspective, which has motivated the emergence of WiFi communities worldwide. The practical exploitation of user-provided local loops, however, raises organizational, administrative, technical, and regulatory issues the solution of which strongly depends on the business models and network architectures adopted by local broadband operators. This paper discusses the relationship between access network architectures and user-provided local loops, pointing out the suitability of neutral access networks as a framework for exploiting end-users’ networking potentials.