Guest Editorial: Special Issue on Clouds for Social Computing

IN recent time, two complimentary Internet based research areas are emerging: social computing and cloud computing. On the one hand, social computing empowers individual users with relatively low technological sophistication to use the web to engage in social interactions, contribute their expertise and share their content, experiences and opinions. On the other hand, cloud computing offers everyone sophisticated computing infrastructures and resources as utilities, so that individual users with relatively low computing knowledge can have at their disposal a high performing computing infrastructure (e.g., compute, storage, applications, etc.) with little investment. Together, these two complementary technological advances form the backbone of our digitized world, when coupled with the rise of sensors, mobile devices and the internet of things. Of course, they also face significant challenges. We briefly look at each area and describe how they complement each other. The Social Web has become an important means of communication for everyone: individuals, organizations, and governments all use it to disseminate and share information, offer opinions and engage in discussions. This medium creates large social networks through which vast amount of information flows quickly and easily. Many events are now first reported on the social web (e.g., Twitter, FaceBook, etc.). This is true for emergencies such as fires or sudden riots, but also news items. For example, the news of the hit on Bin Laden first broke out on Twitter long before the US president officially announced it on the public media. Another instance is the recent Occupy of Wall Street protests which spread out quickly and widely to a larger population due to its Facebook page. The growth andpopularity of social networks pose unique challenges in terms of scalability, maintenance and management. Managing and processing a network with millions of edges (e.g., LinkedIn), distributing status updates to millions of users (e.g., Twitter, Facebook, WhatsUp, etc.), and distributing user generated content to millions of users spread across the globe are some of the practical challenges posed by social networks, or the social web in general, where cloud computing can contribute solutions. An important research area is thus to develop distributed cloud architectures that can handle sustained traffic generated by millions of users in social networks. One of the interesting features of social networks is their growth characteristics: sudden and unpredictable. Social networks grow in members and contents following the principle of human dynamics—bursts followed by a long tail. For example, social media platforms such as Twitter go abuzz when a certain event occurs (e.g., Arab Spring [1], Haiti Earthquake [2], New Zealand Earthquake [3], etc.). To address these sudden needs, high computing resources are required during periods of burst characterized by uncertainty and unpredictability. As a direct result, scalability also becomes a problem, i. e., how resources are scaled to cope with the needs of a sudden burst. Cloud computing, with its inherent features of resources elasticity and having applications, software and hardware provided as a service over the Internet [4], becomes a natural choice to address this problem. This is thus the key point of intersection between the social web and cloud computing. Mobile devices, smartphones in particular, have penetrated our social life, compounding this social communication revolution and its need for scalability of processing power. A recent survey report from TripAdvisor suggests that 87 percent of global travellers use smartphones while on holiday, and 35 percent of US travellers use smartphones for accessing social media. One of the problems with smartphones is the limitation of their battery power. The increasing complexity of new mobile applications puts a heavy load on batteries. To overcome this problem, some techniques off-load mobile computations to software clones of real devices in the cloud. This process involves communication among many entities like mobile devices, their clones, the cloud providers, and mobile network operators. Establishing trust in the communication chain, more specifically with the cloud provider and the mobile network operators, is challenging. A lot of private information could be eavesdropped on and revealed. Yet, as people increasingly employ mobile devices to communicate and interact, both in their private and business lives, secure cloud computing infrastructures are crucial to capturing and processing the data they generate on-the-go. This is the second point of intersection between the social web and cloud computing. More generally, researchers in social computing have started exploiting the availability of cloud computing to crunch the large amount of data resulting from the digitization of social behavior—i.e., the capture of all social behaviors in a digitized world. Data collected from our daily S. Nepal and C. Paris are with CSIRO Computational Informatics, Sydney, Australia. E-mail: {surya.nepal, Cecile.paris}@ndsu.edu. A. Bouguettaya is with the School of Computer Science and Information Technology, RMIT University, Melbourne, Australia. E-mail: [email protected].