Social networks define a ubiquitous complex system which comprises various mathematical models and theories to study its behaviour and to explain and predict its dynamics. Social networks, sometimes called “relationship networks,” help people and organizations connect online to share information and ideas. Concurrently, the ubiquity of smartphones makes them the focal point of the consumer internet economy, as the range of connected devices is now greater than ever. Opportunistic mobile social networks (OMSN) are a form of mobile ad-hoc networks that exploit human social characteristics, such as similarities, daily routines, mobility patterns, and interests to perform message routing and data sharing. In such networks, the users with mobile devices can form on-the-fly social networks to communicate with each other and share data objects.

Unlike mobile ad-hoc networks (MANETs) that require end-to-end communication paths for message exchange, the communication in OMSN occurs on the establishment of opportunistic contacts among mobile nodes, without the availability of end-to-end message routing paths. As mobile devices can make contact only when humans come into contact, such networks are tightly coupled with human social networks. Therefore, the OMSNs exploit human behaviours and social relationships to build more efficient and trustworthy message dissemination schemes, OMSNs have many novel applications such as mobile data traffic offloading, opportunistic computing (utilizing shared resources, content, services, applications, and computing resources, by devices connected in an opportunistic mobile social network, to provide a platform for the execution of distributed computing tasks) and recommender systems (track the user activities, mobility patterns, and utilize the user's contextual information to provide recommendations on variety of items). However at the same time, OMSNs face numerous challenges due to the frequent disruptions and delays, and intermittent connectivity environment. One of the major challenges is the insecure communication in such networks, as due to the distributed nature, it is not possible to utilize mature security mechanisms, such as cryptography that requires centralized trusted authority. Moreover, it is also difficult to maintain trust among the peer nodes due to the disconnected and decentralized environments.

The primary scope of this Special Issue is to deliberate the progress and challenges of using innovative, novel, secure, and smart solutions to define models as well as methods that explore aspects of dynamics in complex mobile social networks. We welcome original research and review articles.

Potential topics include but are not limited to the following:

• Opportunistic communications and social participation
• Social properties in mobile networks
• Data dissemination in opportunistic mobile social networks
• Decision making and real-time monitoring
• Applications of systems science and complexity science in social systems
• User profiling and personalization
• Opportunistic crowd computing
• Recommender systems
• Trust and reputation models
• Opportunistic computing
• Computational offloading
• Secure data routing in OMSN