Armir Bujari

Movement pattern recognition through smartphone's accelerometer

Sensor-enabled smartphones have become a mainstream platform for researchers due to their ability to collect and process large quantities of data, hence creating new opportunities for innovative applications. Yet, the limits in employing sensors to opportunistically detect human behaviors are not clear and deserve investigation. To this purpose, in this article, we discuss movement pattern recognition in day-by-day urban street behavior. As a case study, we restrict at recognizing situations when a pedestrian stops, crosses a street ruled by a traffic light; to do so we only use data coming from the accelerometer of the pedestrians smartphone.

Social-aware delay tolerant networking for mobile-to-mobile file sharing

Peer-to-peer (P2P) overlay networks and mobile ad hoc networks share many key characteristics such as self-organization and decentralization; they also face the crucial challenge of providing connectivity in a decentralized, dynamic environment. However, when considering ad hoc networks composed of mobile devices such as smartphones, we cannot rely on the continuous end-to-end path between peers as for classic Internet P2P applications; rather, we have to deal with low node density that creates mobile-disconnected networks. Porting the P2P paradigm into mobile networks to create a mobile-to-mobile file sharing application will create a modern type of delay/disruption tolerant network. In this context, we discuss our new approach for P2P file sharing that considers networks composed of mobile smartphones. As an innovative feature, we leverage on peer mobility to reach data in other disconnected networks by implementing a delay/disruption tolerant network-like store-delegate-and-forward communication model, where a peer can delegate unaccomplished file download tasks to other peers. In order to increase the chances of eventually receiving the requested file while reducing the number of transmitted messages and data, social awareness is exploited by nodes to delegate unaccomplished tasks only to peers that are expected to be encountered again in the future. Copyright

A survey on interactive games over mobile networks

The mobile revolution has brought us the possibility to enjoy our favorite applications anywhere and anytime. In this context, interactive games over mobile networks embody a fascinating case study both for their commercial success and for their technical challenges, thus, sparking interest and development. The current state of the art of interactive games over mobile networks is captured in this article. We discuss main requirements and analyze possible combinations of existing solutions to provide better support for highly interactive game sessions with mobile players. Copyright

Using gamification to discover cultural heritage locations from geo-tagged photos

Many enchanting cultural heritage locations are hidden from tourists, especially when considering countries full of historic attractions. Tourists tend to consider only mainstream monuments and towns, neglecting wonderful little jewels along their travel itinerary. However, this is generally not their fault, as travelers cannot be aware of all the surrounding beauties when visiting a new region. To this aim, we discuss and analyze here PhotoTrip, an interactive tool able to autonomously recommend charming, even if not mainstream, cultural heritage locations along travel itineraries. PhotoTrip is able to identify these points of interest by gathering pictures and related information from Flickr and Wikipedia and then provide the user with suggestions and recommendations. An important technical challenge for this kind of services is the ability to provide only the most relevant pictures among the many available for any considered itinerary. To this aim, we have exploited social networks, crowdsourcing and gamification to involve users in the process of improving the response quality of our system.

A delay/disruption tolerant solution for mobile-to-mobile file sharing

Due to mobility, communication links between mobile nodes are transient and network maintenance overhead is a major performance bottleneck for data transmission. Low node density makes it difficult to establish end-to-end connection, thus impeding a continuous end-to-end path between a source and a destination. This creates a modern type of DTN, which was originally intended for communication in outer space, but is now directly accessible from our pockets. In this paper, we present a special purpose system for searching and transferring files tailored to both the characteristics of MANETs and the requirements of P2P file sharing. Our approach is based on an application layer overlay network. We port a DTN type solution into an infrastructure-less environment like MANETs and leverage peer mobility to reach data in other disconnected networks. This is done by implementing an asynchronous communication model, store-delegate-and-forward, like DTNs, where a peer can delegate unaccomplished file download or query tasks to special peers. To improve data transmission performance while reducing communication overhead, we select these special peers by the expectation of encountering them again in future and assign them different download starting point on the file.

A solution for mobile DTN in a real urban scenario

The growing number of mobile devices equipped with a wireless interface and the end-user trend to shift toward wireless technology is opening new possibilities for networking. In particular, opportunistic communication embodies a feasible solution for environments with scarce or costly infrastructure-based connectivity. In this context we provide a delay-tolerant solution that provides service opportunistic connectivity. Our approach follows the Delay/Disruption Tolerant Network (DTN) paradigm by implementing a store-carry-and-forward communication model among mobile users and buses, the latter embodying carrier entities. A user can delegate the carrier a request which involves Internet access. This request is then forwarded to the bus stations Internet Gateway (IG) in an opportunistic fashion, including both data muling and multi-hop transmission through other buses. Once the request is served at the bus stations IG, the result is opportunistically sent back toward the bus line where the user expects the result. In this paper we present our idea and discuss results obtained through simulations in a realistic urban scenario.

A Survey of Opportunistic Data Gathering and Dissemination Techniques

Opportunistic Networking (ON) is an emerging networking paradigm exploiting contact opportunities and node mobility to move data between nodes. Differently from infrastructure networks, where conventional information like network topology could be used to route messages, ON demands for new techniques able to cope with a dynamic evolving network topology and scenarios with limited or no information. Further, the heterogeneity of the autonomous actors involved in the network processes translates into different network protocol constraints which, if not considered carefully could lead to scalability problems of the devised solutions. In this context, in this article, we provide a survey of relevant opportunistic solutions and their motivation, with emphasis on the data gathering and dissemination processes. Despite the major research effort, it emerges there is no one silver bullet.

P2P file sharing on mobile phones: Design and implementation of a prototype

Mobile phones have already evolved from simple voice communication means into a powerful device able to handle multimedia documents, personal productivity applications, and all sort of connections to the Internet. It is hence expected to see a popular application such as file sharing to become widely utilized even in this context. Indeed, the combination among mobile users and file sharing seems a match made in heaven: people could exchange files of interest just passing by each other. Moreover, new context related applications may be developed to exploit this possibility enriching our lives. In this work, we present design issues and implementation details about a real P2P file sharing application for mobile phones.

An overview of opportunistic ad hoc communication in urban scenarios

In the era of the Internet of Everything, users with handheld or wearable devices equipped with sensing capability have become producers as well as consumers of information and services. The more powerful these devices get, the more likely it is that they will generate and share content locally, through ad hoc opportunistic connectivity, leading to the presence of distributed information sources and forwarders and the diminishing role of centralized, infrastructure-based servers. Despite this interesting portrait, the mobile and volatile nature of this network presents severe challenges demanding new networking techniques able to cope with the unpredictable and resource-constrained nature of mobile entities comprising it. In this context, we discuss novel data gathering and dissemination strategies in urban scenarios which do not rely on strict infrastructure mediation. While preserving the general aspects of our study and without loss of generality, we focus our attention toward practical applicative case studies which help us capture the characteristics of ad hoc opportunistic communication networks, and devise efficient solutions for use in real applicative contexts.

Vegas Over Access Point: Making Room for Thin Client Game Systems in a Wireless Home

Cloud-based entertainment is gaining momentum. With the cost of commodity hardware lowering by the day and the consumer market penetration of in-house digital entertainment systems, a new generation of interactive services has come into being. This new technological wave has launched new content producers and providers that are rapidly adapting to match the consumer demand. In this context, thin client or cloud-based gaming is attracting much attention, shifting the computational burden to the cloud while the consumer enjoys a fat video feed accessed through its thin client via the shared wireless gateway. However, this model of interaction raises new challenges that demand for specific networking solutions aimed at addressing the heterogeneous flow coexistence problem at the home wireless gateway. We propose a solution to this problem by devising a Transmission Control Protocol Vegas-like congestion control algorithm deployed on top of the home gateway. Our solution works out of the box with the standard protocols at the server, router, and client levels, thereby making deployment straightforward. Experimental assessment with real traffic traces shows that our solution addresses the problem effectively.