Social networks drive todays opinion and content diffusion. Humans interact in social media on the basis of their emotional states and it is important to capture people emotional scales for a particular theme. Such interactions are facilitated and become evident in smart environments characterized by mobile devices and new smart city contexts. This work proposes a sentiment analysis approach wh...

Youngsters maintain contact with each other through social-networking websites. We propose new ways of nurturing contacts by monitoring users’ activity with mobile phones (i.e., by monitoring text messages, phone calls, and encounters captured by Bluetooth). We show that, based on user’s activity, one is able to recommend new friends, track health of friendships (and alert users they may be neg...

Opportunistic Mobile Social Networks (OMSNs), formed by people moving around carrying mobile devices, enhance spontaneous communication among users that opportunistically encounter each other without additional infrastructure. Multicast is an important communication service in OMSNs. Most of the existing multicast algorithms neglect or adopt static social factors that are inadequate to catch no...

The widely used mobile phone, as well as its related technologies had opened opportunities for a complete change on how people interact and build relationship across geographic and time considerations. The convenience of instant communication by mobile phones that broke the barrier of space and time is evidently the key motivational point on why such technologies so important in people's life a...

The construction of social networks over mobile devices in the events or at locations has emerged as a new network paradigm. These new mobile social networks enable people to communicate and share their experiences without the need to have Internet access and with minimum required infrastructure. However, the functionality and security of such networks would be potentially undermined without an...

The security of communication in everyday life becomes very important. On the other hand, all existing encryption protocols require from user additional knowledge end resources. In this paper we discuss the problem of public key distribution between interested parties. We propose to use a popular social media as a channel to publish public keys. This way of key distribution allows also easily c...

We analyze a massive social network gathered from a large mobile phone operator’s records, comprised of millions of users and tens of millions of calls. We examine the following questions: what is the distribution of phone calls per customer; total talk time per customer; and distinct partners per customer? We find that these distributions are skewed, and that they significantly deviate from wh...