Three applications for mobile epidemic algorithms

This paper presents a framework for the pervasive sharing of data using wireless networks. 'FarCry' uses the mobility of users to carry files between separated networks. Through a mix of ad-hoc and infrastructure-based wireless networking, files are transferred between users without their direct involvement. As users move to different locations, files are then transmitted on to other users, spreading and sharing information. We examine three applications of this framework. Each of these exploits the physically proximate nature of social gatherings. As people group together in, for example, business meetings and cafés, this can be taken as an indication of similar interests, e.g. in the same presentation or in a type of music. MediaNet affords sharing of media files between strangers or friends, MeetingNet shares business documents in meetings, and NewsNet shares RSS feeds between mobile users. NewsNet also develops the use of pre-emptive caching: collecting information from others not for oneself, but for the predicted later sharing with others. We offer observations on developing this system for a mobile, multi-user, multi-device environment

An Internet Heartbeat

Obtaining sound inferences over remote networks via active or passive measurements is difficult. Active measurement campaigns face challenges of load, coverage, and visibility. Passive measurements require a privileged vantage point. Even networks under our own control too often remain poorly understood and hard to diagnose. As a step toward the democratization of Internet measurement, we consider the inferential power possible were the network to include a constant and predictable stream of dedicated lightweight measurement traffic. We posit an Internet "heartbeat," which nodes periodically send to random destinations, and show how aggregating heartbeats facilitates introspection into parts of the network that are today generally obtuse. We explore the design space of an Internet heartbeat, potential use cases, incentives, and paths to deployment

Subversion Over OpenNetInf and CCNx

We describe experiences and insights from adapting the Subversion version control system to use the network service of two information-centric networking (ICN) prototypes: OpenNetInf and CCNx. The evaluation is done using a local collaboration scenario, common in our own project work where a group of people meet and share documents through a Subversion repository. The measurements show a performance benefit already with two clients in some of the studied scenarios, despite being done on un-optimised research prototypes. The conclusion is that ICN clearly is beneficial also for non mass-distribution applications. It was straightforward to adapt Subversion to fetch updated files from the repository using the ICN network service. The adaptation however neglected access control which will need a different approach in ICN than an authenticated SSL tunnel. Another insight from the experiments is that care needs to be taken when implementing the heavy ICN hash and signature calculations. In the prototypes, these are done serially, but we see an opportunity for parallelisation, making use of current multi-core processors

ABAKA : a novel attribute-based k-anonymous collaborative solution for LBSs

The increasing use of mobile devices, along with advances in telecommunication systems, increased the popularity of Location-Based Services (LBSs). In LBSs, users share their exact location with a potentially untrusted Location-Based Service Provider (LBSP). In such a scenario, user privacy becomes a major con- cern: the knowledge about user location may lead to her identification as well as a continuous tracing of her position. Researchers proposed several approaches to preserve users’ location privacy. They also showed that hiding the location of an LBS user is not enough to guarantee her privacy, i.e., user’s pro- file attributes or background knowledge of an attacker may reveal the user’s identity. In this paper we propose ABAKA, a novel collaborative approach that provides identity privacy for LBS users considering users’ profile attributes. In particular, our solution guarantees p -sensitive k -anonymity for the user that sends an LBS request to the LBSP. ABAKA computes a cloaked area by collaborative multi-hop forwarding of the LBS query, and using Ciphertext-Policy Attribute-Based Encryption (CP-ABE). We ran a thorough set of experiments to evaluate our solution: the results confirm the feasibility and efficiency of our proposal

Performance evaluation of floating content for context-aware applications

Context-awareness is a peculiar characteristic of an expanding set of applications that make use of a combination of restricted spatio-temporal locality and mobile communications, to deliver a variety of services. Opportunistic communications satisfy well the communication requirements of these applications, because they naturally incorporate context. Recently, an opportunistic communication paradigm called "Floating Content" was proposed, to support infrastructure-less, distributed content sharing. It aims at ensuring the availability of data within a certain geographic area called "anchor zone". In literature, the focus was on understanding the asymptotic properties of the floating lifetime, i.e., the duration of time for which content floats in the anchor zone. Instead, our objective is to characterize the performance of context-aware applications using floating content as a communication service. First, we present a simple approximate analytical model for accessing the viability of floating content to act as a communication service for context-aware applications. We focus on the "success probability", which captures the likelihood for a user to receive the content when traversing the anchor zone and apply our analysis to estimate the success probability for three representative categories of context-aware applications, and show how the system can be configured to achieve the application’s target. Second, we investigate the impact of different mobility models on the performance of context-aware applications that use floating content. In particular, we consider four different mobility models, and, by using extensive simulation experiments, we investigate the performance of three different categories of context-aware applications. By comparing the simulation results to the performance predictions of our previously proposed simple analytical model, we show that our model can provide useful performance predictions even for complex and realistic mobility models. Simulation results under different mobility models also confirm the viability of floating content to act as a communication service for a variety of context-aware applications. Finally, we investigate the performance of floating content in a real world setting by developing and deploying an Android mobile application based on floating content in an office and a university campus environment. To the best of our knowledge, this is the first ever experimental evaluation of floating content service in a real setting. Our results provide quite interesting indications for the viability and the implementation of applications using floating content in the considered environments. We also propose a novel simple analytical model that accounts for the peculiarities of the mobility patterns in such a real world setting, and that can accurately predict the effectiveness of floating content for the implementation of context-aware applications in an office and a campus setting.Programa Oficial de Doctorado en Ingeniería TelemáticaPresidente: Claudio E. Casetti.- Secretario: Carlos Jesús Bernardos Cano.- Vocal: Antonio García Marqué