Christian Quadri

Opportunistic mobile games using public transportation systems: a deployability study

With the growing availability of personal communication devices, we are witnessing a tremendous increase in the demand for mobile services based on location and context. Mobile gaming as a service is, of course, no exception. Unfortunately, differently from other services, location- and context-based gaming strictly requires near-field communication to interact with nearby players to create teams and arenas. Since currently adopted technologies suffer from scalability (Bluetooth) or energy (WiFi) constraints, opportunistic networks (ONs) have already been addressed as a viable solution to involve a considerable number of players on a wider area. Nevertheless, it is not yet clear how player experience will be affected by the increased delay and probabilistic message forwarding introduced by an ON. In this paper, we address the aforementioned problems by studying, by means of simulations, the feasibility to deploy a contact-based game on top of the ON provided by the public transportation systems (PTSs) of three cities: Milan (Italy), Edmonton (AB, Canada), and Chicago (IL, USA). Furthermore, to provide playability and scalability considerations, we also study an opportunistic collaborative version of a famous standalone game. The focus on this specific game is functional to foster the use of the PTS itself. The contribution of this paper is twofold. Firstly, we provide simulation results hinting that deployment on a PTS is feasible when targeting users commuting inside the city. Secondly, we provide a number of considerations and guidelines for game designers to actually deliver a compelling and intriguing experience.

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.

Multidimensional human dynamics in mobile phone communications

In todays technology-assisted society, social interactions may be expressed through a variety of techno-communication channels, including online social networks, email and mobile phones (calls, text messages). Consequently, a clear grasp of human behavior through the diverse communication media is considered a key factor in understanding the formation of the todays information society. So far, all previous research on user communication behavior has focused on a sole communication activity. In this paper we move forward another step on this research path by performing a multidimensional study of human sociality as an expression of the use of mobile phones. The paper focuses on user temporal communication behavior in the interplay between the two complementary communication media, text messages and phone calls, that represent the bi-dimensional scenario of analysis. Our study provides a theoretical framework for analyzing multidimensional bursts as the most general burst category, that includes one-dimensional bursts as the simplest case, and offers empirical evidence of their nature by following the combined phone call/text message communication patterns of approximately one million people over three-month period. This quantitative approach enables the design of a generative model rooted in the three most significant features of the multidimensional burst - the number of dimensions, prevalence and interleaving degree - able to reproduce the main media usage attitude. The other findings of the paper include a novel multidimensional burst detection algorithm and an insight analysis of the human media selection process.

On the scalability of delay-tolerant routing protocols in urban environment

In these last years the demand for personal and ubiquitous communication has raised at a tremendous rate. Mobile services, which are nowadays typically offered based on location and context, suffer from various 3G shortcomings, and many data providers are looking for innovative solutions offering a carrier-independent, location-based, and cheaper than 3G data distribution. The deployment of a Delay Tolerant Network (DTN) in a urban scenario seems to be a viable solution to support city-wide information services exploiting public transportation systems as virtual backbones. The majority of DTN routing protocols make use of a multi-copy forwarding approach and are usually designed for campus-wide or rural area communication. The contribution of this paper is an assessment on the scalability limits of popular DTN routing protocols when applied to a real city using its actual public transportation system. We show that multi-copy algorithms do not scale well to a huge area and demonstrate that performance of a probability-based single-copy algorithm degrades more gracefully even with very high levels of traffic.

On the Feasibility of Opportunistic Collaborative Mixed Reality Games in a Real Urban Scenario

In these last years the growing availability of personal mobile devices has boosted the demand for mobile services offered based on location and context. Mobile gaming services are, of course, no exception. Unfortunately, the 3G networks infrastructure struggles to keep pace due to scalability limitations and a pull-based service model. One feasible solution, also for gaming, is to adopt an Opportunistic Network (ON) to exploit unplanned contact opportunities between players to perform data exchange and forwarding in ad hoc mode. When designing a game for an ON, the main issue is about forecasting the feasibility of a given gameplay when applied to a real - and complex - environment. In this paper we address this issue proposing an opportunistic game that is meaningful for the category of collaborative puzzle games. The game is evaluated by means of simulations on the topology of a real city in order to understand its scalability and setback on the gameplay.

Scaling online collaborative games to urban level

With the growing availability of personal communication devices we are witnessing a tremendous increase in the demand for mobile services based on location and context. Mobile gaming is, of course, following this same trend. Unfortunately, differently from other services, location- and context-based gaming strictly requires near-field communication to interact with nearby players in order to create teams and arenas. Since currently adopted technologies suffer from scalability (Bluetooth) or energy (WiFi) constraints, Opportunistic Networks (ONs) have already been addressed as a viable solution to involve a considerable number of players on a wider area. While massive multiplayer games are commonplace on wired networks, it is not yet clear how player experience is affected by the increased delay and probabilistic message forwarding introduced by a huge population over an ON. In this paper we address this problem by proposing an opportunistic collaborative game, which is meaningful for the category of collaborative puzzle games, and evaluating its playability and scalability by means of simulations on a real city topology.

Urban communications and social interactions through the lens of mobile phone data

Abstract The social network built on top of mobile phone data has drawn increasing attention in recent years, due to its being far more accurate than its online counterpart in mirroring people’s offline sociality. In this paper, we leverage a large dataset of mobile Call Detail Records (CDRs), provided by one of the primary Italian operators, to build the multiplex social network given by call and text message activities of the operator’s subscribers. By discussing the multiplex network characteristics – ranging from ego-networks, dyads and triads all the way to cliques – the paper offers a comprehensive and thorough overview of human sociality as carried on through mobile phone; in addition, it highlights the need to consider more than one communication media when aiming to understand people’s sociality.Finally, by investigating on-phone cliques, we show people’s inclination to gather in cohesive and restricted groups of close friends, thus providing strong ominous indicators of where many recent online social networks, namely Snapchat, WeChat and others, are leading.

Big-Data Inspired, Proximity-Aware 4G/5G Service Supporting Urban Social Interactions

Unlike virtual sociality, in their daily social behavior individuals are used to communicate with a limited number of persons and periodically meet their inner social circle in specific city locations to perform common social activities. Physical encounters among a restricted number of people interestingly give rise to a significant amount of in-proximity voice/data traffic on the cellular network and advocate the provisioning of a new class of services supporting it. This paper gives empirical evidence of the role played by these location-centered social interactions through the extensive analysis of a large anonymized dataset of Call Detail Records (CDR) relying on the phone activities of nearly 1 million people in the city of Milano. The analysis and understanding of these human interactions have inspired the design of a new mobile service that detects, after users consent, proximity with a person in my inner social circle and autonomously deploys the mobile social network supporting proximity interactions. The approach we propose brings together a few important contributions: first, it concretely shows that the current NFV-enabled trend of placing cloud services at the edge of the operators network has a payoff in terms of traffic offloading and improved users experience; secondly, it demonstrates for the first time that a few typical cloud-based services can actually be directly performed by the mobile network operator by simply leveraging the rich amount of data they possess and never exploit.

Calling and Texting: Social Interactions in a Multidimensional Telecom Graph

The growing awareness that human communications and social interactions are assuming a stratified structure, due to the availability of multiple techno-communication channels, including online social networks, mobile phone calls, short messages (SMS) and e-mails, has recently led to the study of multidimensional networks. In this context we perform the first study of the multiplex mobile social network, gathered from the records of both call and text message activities of millions of users of a large mobile phone operator over a period of 12 weeks. While social networks constructed from mobile phone datasets have drawn great attention in recent years, so far studies have dealt with text message and call data, separately, providing a very partial view of people sociality expressed on phone. Here we analyze how the call and the text message dimensions overlap showing how many information about links and nodes could be lost only accounting for a single layer and how users adopt different media channels to interact with their neighborhood.

THINPLE - the new online Sociality is built on top of NFC-based Contacts

The rapid densification of todays online social networks is progressively draining their early value of mirroring real life sociality. This paper describes THINPLE, a novel mobile computing app aiming at building a protected and trusted online social space where the growth of the sociality of a person is only fuelled by contacts in the physical world. THINPLE exploits each physical contact, through the short radio range of Near Field Communication, NFC, to capture the explicit willingness and trustworthiness to initiate a online relationship. Moreover, through physical contacts, inanimate objects of the real world can be added to the online sociality of individuals, thus turning into practice the concept of Internet of things and people.