Franca Delmastro

Experimenting an indoor bluetooth-based positioning service

The Bluetooth wireless technology is an emerging technology originally designed as a short-range connectivity solution for personal, portable, and handheld electronic devices. This paper briefly presents the functionality, and the architecture of an indoor positioning service based on this technology. Most of the design choices for the service have been strongly influenced by Bluetooth features. The effectiveness of the indoor positioning service is critically analyzed. Experimental and simulation results used for defining the policy of mobile device discovery are shown.

CAMEO: A novel context-aware middleware for opportunistic mobile social networks

Abstract Mobile systems are characterized by several dynamic components such as user mobility, device interoperability, and interactions among users and their devices. In this scenario, context-awareness and the emerging concept of social-awareness become a fundamental requirement to develop optimized systems and applications. In this paper we present CAMEO, a light-weight context-aware middleware platform for mobile devices designed to support the development of real-time mobile social network (MSN) applications. MSNs extend the paradigm of online social networks with additional interaction opportunities generated by user mobility and opportunistic wireless communications among users which share interests, habits, and needs. Specifically, CAMEO is designed to collect and reason upon multidimensional context information, derived by the local device, the local user, and their physical interactions with other devices and users. It provides a common application programming interface to MSN applications through which they can exploit context- and social-aware functionalities to optimize their features. CAMEO has been implemented on an Android platform together with a real example of an MSN application. Validation and performance evaluation have been conducted through an experimental testbed.

Pervasive communications in healthcare

The evolution of wireless communication technologies opened the way to the definition of innovative eHealth systems aimed at providing a continuous and remote support to patients and new instruments to improve the workflow of the medical personnel. This paper presents a survey of wireless communication technologies currently applied in eHealth systems, deeply analysing communication standards, protocols and performance results achieved in this field. The analysis of advantages and drawbacks of current technologies introduces also the definition of new research issues and possible solutions for future eHealth systems.

Experimental comparison of routing and middleware solutions for mobile ad hoc networks: legacy vs cross-layer approach

In this paper we present an experimental evaluation of a full ad hoc network architecture with particular attention to routing and middleware layers. In particular we set up a MANET prototype on which we performed a large set of experiments: in a first phase, we analyzed performances of a proactive and a reactive routing protocols in case of low mobility scenarios in small-medium scale ad hoc networks; then we studied the performances of a first prototype of an optimized p2p system for ad hoc networks (CrossROAD), based on a cross-layer interaction with a proactive routing protocol. Our analysis shows that the use of a proactive routing protocol does not negatively influence system performances, furthermore it allows the optimization of a structured p2p system on ad hoc networks, providing a complete and timely updated knowledge of the network topology. In this way, the overlay network is completely self-organizing and correctly manages network partitioning and topology changes.

People-centric computing and communications in smart cities

The extremely pervasive nature of mobile technologies, together with the users need to continuously interact with her personal devices and to be always connected, strengthen the user-centric approach to design and develop new communication and computing solutions. Nowadays users not only represent the final utilizers of the technology, but they actively contribute to its evolution by assuming different roles: they act as humans, by sharing contents and experiences through social networks, and as virtual sensors, by moving freely in the environment with their sensing devices. Smart cities represent an important reference scenario for the active participation of users through mobile technologies. It involves multiple application domains and defines different levels of user engagement. Participatory sensing, opportunistic sensing, and mobile social networks (MSNs) currently represent some of the most promising people-centric paradigms. In addition, their integration can further improve the user involvement through new services and applications. In this article we present SmartCitizen app, an MSN application designed in the framework of a smart city project to stimulate the active participation of citizens in generating and sharing useful contents related to the quality of life in their city. The app has been developed on top of a context- and social-aware middleware platform (CAMEO) able to integrate the main features of people-centric computing paradigms, lightening the app developers effort. Existing middleware platforms generally focus on a single people-centric paradigm, exporting a limited set of features to mobile applications. CAMEO overcomes these limitations and, through Smart- Citizen, we highlight the advantages of implementing this type of mobile application in a smart city scenario. Experimental results shown in this article can also represent the technical guidelines for the development of heterogeneous people-centric mobile applications embracing different application domains.

Implementation of CAMEO: A context-aware middleware for Opportunistic Mobile Social Networks

Opportunistic Mobile Social Networks represent the emerging trend in mobile applications combining the novel paradigm of opportunistic networking with the need of users to generate and share contents anywhere and anytime. In this demo we present a real implementation of a context-aware middleware for the development of optimized opportunistic Mobile Social Networks. To highlight the advantages of this platform we present also an innovative application for tourists aimed at enriching the touristic experience with useful information and virtual social interactions with other users.

Effects of unstable links on AODV performance in real testbeds

A link between a pair of nodes is defined unstable if it is characterized by a packet loss which is not negligible in one or both directions. The presence of unstable links in multihop ad hoc networks is very likely and it depends on several factors (e.g., different transmission capabilities of the devices, interferences caused by additional wireless devices). Their management by the routing protocols is of paramount importance since they negatively affect applications performance. In our previous experimental studies, we found that AODV is characterized by very low performance in some specific situations and, in this work, we demonstrate that it mainly depends on the wrong management of unstable links as valid routes. We present some policies that have been proposed in literature to avoid this problem, and we validate two of them through experimental results, exploiting also a direct comparison with the proactive routing protocol OLSR. Our results show that AODV is not able to avoid the use of unstable links, even when an alternative stable route exists. In the same conditions, OLSR outperforms AODV by correctly managing unstable links. In fact, it is able to guarantee a higher packet delivery ratio to the application by using the most stable path to reach the destination.

Social-aware Content Sharing in Opportunistic Networks

Opportunistic networks represent the emerging pervasive communication paradigm that supports intermittent connectivity scenarios. To develop reliable data exchange and communications both protocols and services can be enhanced exploiting context and content information, defining thus a novel data-centric communication paradigm. In this demo we present a socialaware content sharing service based on the exchange of a combination of the user personal information, interests, social relationships and information related to shared contents. In this way, the system is able to implement cooperative downloading mechanisms allowing users to share files even they will never be directly connected.

XScribe: a stateless, cross-layer approach to P2P multicast in multi-hop ad hoc networks

Using p2p systems on multi-hop ad hoc networks is an amazingly interesting challenge. While the features of p2p systems designed for Internet are particularly suitable for ad hoc networking environments, the very assumptions behind their design are usually at odds with the ad hoc network distinctive features. It is thus challenging to port p2p features to ad hoc networks in an efficient way. In this work we focus on p2p multicasting, and design a Scribe cross-layer replacement, suitable for ad hoc networks (XScribe). We discuss the main XScribe features, and evaluate its performance on a real multi-hop ad hoc network. Results show that XScribe drastically improves the Scribe performance in terms of packet loss and delay. At the same time, they also indicate XScribe limitations, and suggest directions to further improve its design.

MobileMAN: integration and experimentation of legacy mobile multihop ad hoc networks

Although research on mobile ad hoc networks has been ongoing for some time, there are relatively few experiences with real ad hoc networks in laboratory testbeds, and users never use multihop ad hoc networks. This seems due to a gap between what end users might find useful, and what research is currently addressing. Indeed, a large portion of research activities concentrate on the development of novel solutions to optimize lower-layer protocols in often unrealistic settings, while little attention is devoted to the quality of service (QoS) these networks may provide to end users in realistic applicative scenarios. The MobileMAN project tried to contribute to reduce this gap by promoting a research plan aimed at combining theoretical research with the integration of developed solutions in prototypes to be used for validating them in realistic small- and medium-scale scenarios (few hops and 10‐20 nodes). The aim is to design and integrate a full protocol stack and experimentally quantify the QoS the system is able to provide to the users. This research approach points out that, also in this limited setting, several problems still exist to construct efficient multihop ad hoc networks. In the next article [1] we discuss how cross layering can be exploited to fix some performance problems identified in our analyses.