1,720,966 research outputs found
A Reputation-based Approach to Tolerate Misbehaving Carriers in Delay Tolerant Networks
No full textDelay Tolerant Network (DTN) is a network paradigm used to deliver messages when network connectivity is not guaranteed. In a DTN, communication is made possible by carriers, mobile nodes that physically carry messages from a network partition to another. Selecting carriers that provide the best delivery probability is a crucial issue. However, if carriers misbehave, the integrity and availability of a DTN is endangered. In this paper we present a decentralised reputation-based system aimed at tolerating misbehaving carriers. A prototype of the system has been integrated into Context Aware Routing (CAR) [1]. Simulations show that the resulting system RCAR provides a greater delivery probability than CAR and Epidemic Routing [2] without increasing the average delivery delay
A Cryptographic Suite for Underwater Cooperative Applications
No full textAn underwater acoustic scenario raises many problems in terms of security because of the limited bandwidth provided by the underwater medium. In this paper we face with the problem of secure cooperation among underwater acoustic vehicles. We propose a cryptographic suite able to reduce at the minimum the message overhead added by security. The cryptographic suite provides vehicles authentication, confidentiality and integrity of messages and key management. A prototype has been implemented and preliminary performance evaluation tests are shown
Towards a Reputation-based Routing Protocol to Contrast Blackholes in a Delay Tolerant Network
No full textA Delay Tolerant Network (DTN) relies on the implicit assumption that nodes cooperate towards message forwarding. However, this assumption cannot be satisfied when there are malicious nodes acting as blackholes and voluntarily attracting and dropping messages.
In this paper we propose a reputation-based protocol for contrasting blackholes. Every node locally maintains the reputation of forwarding nodes it comes in touch with and, then, upon selecting the next forwarding node, the node chooses among those having the highest reputation. The proposed reputation protocol is composed of three basic mechanisms—acknowledgments, node lists, and aging—that make communication efficient and capable of adapting to the changing operating conditions of a DTN.
The protocol has been used to extend CAR [1]. The resulting protocol RCAR (reputation-based CAR) has been compared with T-ProPHET [2], a state-of-the-art reputation-based DTN routing protocol, from several standpoints. As it turns out, RCAR is more effective than T-ProPHET and outperforms it in most cases
Mobile underwater sensor networks for protection and security: field experience at the UAN11 experiment
Get PDFThe EU-funded project UAN (Underwater Acoustic Network) was aimed at conceiving, developing, and testing at sea an innovative and operational concept for integrating underwater and above-water sensors in a unique communication system to protect offshore and coastline critical infrastructures. This work gives details on the underwater part of the project. It introduces a set of original security features and gives details on the integration of autonomous underwater vehicles (AUVs) as mobile nodes of the network and as surveillance assets, acoustically controlled by the command and control center to respond against intrusions. Field results are given of the final UAN project sea trial, UAN11, held in May 2011 in Norway. During the experimental activities, a UAN composed of four fixed nodes, two AUVs, and one mobile node mounted on the supporting research vessel was operated continuously and integrated into a global protection system. In this article, the communication performance of the network is reported in terms of round-trip time, packet loss, and average delivery ratio. The major results of the experiment can be thus summarized: the implemented network structure was successful in continuously operating over five days with nodes seamlessly entering and exiting the network; the performance of the network varied greatly with fluctuations in the acoustic channel; the addition of security features induced a minor degradation in network performance with respect to channel variation; the AUVs were successfully controlled from a remote station through acoustic signals routed by the network
Secure Cooperation of Mobile Sensors in an Underwater Acoustic Network
No full textMethodologies and algorithms are presented for the
secure cooperation of a team of mobile underwater sensors,
connected through an acoustic communication network, within
surveillance and patrolling applications. The work proposes a
cooperative algorithm where the mobile underwater sensors
(installed on Autonomous Underwater Vehicles – AUVs) respond
to simple local rules based on the available information to
perform the mission and maintain the communication link with
the network. The algorithm is intrinsically robust, in the sense
that with loss of communication among the vehicles the coverage
performance (i.e., the mission goal) is degraded but not lost. The
cooperative algorithm relies however on the fact that the available
information from the other sensors, though not necessarily
complete, is trustworthy. To ensure trustworthiness, a secure
communication suite has been designed specifically oriented to the
underwater scenario
A Secure Communication Suite for Underwater Acoustic Sensor Networks
Get PDFIn this paper we describe a security suite for Underwater Acoustic Sensor Networks comprising both fixed and mobile nodes. The security suite is composed of a secure routing protocol and a set of cryptographic primitives aimed at protecting the confidentiality and the integrity of underwater communication while taking into account the unique characteristics and constraints of the acoustic channel. By means of experiments and simulations based on real data, we show that the suite is suitable for an underwater networking environment as it introduces limited, and sometimes negligible, communication and power consumption overhead
Tour-pedia: a Web Application for Sentiment Visualization in Tourism Domain
No full textTour-pedia is a Web application which shows the sentiment of users about touristic locations in some of the most important cities and regions in Europe. It is implemented within the OpeNER project, which aims to provide a pipeline for processing natural language. More specifically, Tour-pedia, exploits the OpeNER pipeline to analyse users' reviews on places. All reviews are extracted from social media. Once analysed, each review is associated to a rate, which ranges from 0 to 100. The sentiment of each place is calculated as a function of all the reviews sentiment on that place. As a result, Tour-pedia shows all the places and their users sentiments on a map
AUVs as mobile nodes in acoustic networks: field experience at the UAN10 experiment
No full textThe UAN - Underwater Acoustic Network - project has among its goals the investigation of networked communication modalities in which mobile nodes are located in the environment in order to optimize the communication characteristics of the acoustic channel. The mobile network nodes in UAN are placed on Autonomous Underwater Vehicles (AUVs) carrying appropriate acoustic modems and capable of autonomous decisions. With this contribution we focus on the architectural design and implementation on AUVs of the "Folaga" class of a mission supervisor handling the communication, environmental sampling and decision making tasks, and reports the first results in terms of network communication capabilities as obtained in the UAN10 experimental activities that took place the Tuscan Archipelago, Mediterranean Sea, in September 2010
Towards a DBpedia of tourism: The case of Tourpedia
No full textIn this paper we illustrate Tourpedia, which would be the DBpedia of tourism. Tourpedia contains more than half a million places, divided in four categories: accommodations, restaurants, points of interests and attractions. They are related to eight locations: Amsterdam, Barcelona, Berlin, Dubai, London, Paris, Rome and Tuscany, but new locations are continuously added. Information about places were extracted from four social media: Facebook, Foursquare, GooglePlaces and Booking and were integrated in order to build a unique catalogue. Tourpedia provides also a Web API and a SPARQL endpoint to access data
Secure Cooperation of Autonomous Mobile Sensors Using an Underwater Acoustic Network
No full textMethodologies and algorithms are presented for the secure cooperation of a team of autonomous mobile underwater sensors, connected through an acoustic communication network, within surveillance and patrolling applications. In particular, the work proposes a cooperative algorithm in which the mobile underwater sensors (installed on Autonomous Underwater Vehicles—AUVs) respond to simple local rules based on the available information to perform the mission and maintain the communication link with the network (behavioral approach). The algorithm is intrinsically robust: with loss of communication among the vehicles the coverage performance (i.e., the mission goal) is degraded but not lost. The ensuing form of graceful degradation provides also a reactive measure against Denial of Service. The cooperative algorithm relies on the fact that the available information from the other sensors, though not necessarily complete, is trustworthy. To ensure trustworthiness, a security suite has been designed, specifically oriented to the underwater scenario, and in particular with the goal of reducing the communication overhead introduced by security in terms of number and size of messages. The paper gives implementation details on the integration between the security suite and the cooperative algorithm and provides statistics on the performance of the system as collected during the UAN project sea trial held in Trondheim, Norway, in May 2011
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