Mobile devices integrating wireless short-range communication technologies make possible new applications for spontaneous communication, interaction and collaboration. An interesting approach is to use collaboration to facilitate communication when mobile devices are not able to establish direct communication paths. Opportunistic networks, formed when mobile devices communicate with each other while users are in close proximity, can help applications still exchange data in such cases. In opportunistic networks routes are built dynamically, as each mobile device acts according to the store-carry-and-forward paradigm. Thus, contacts between mobile devices are seen as opportunities to move data towards destination. In such networks data dissemination is done using forwarding and is usually based on a publish subscribe model. Opportunistic data dissemination also raises questions concerning user privacy and incentives. Such problems are addressed dierently by various opportunistic data dissemination techniques. In this we analyze existing relevant work in the area of data dissemination in opportunistic networks. We present the categories of a proposed taxonomy that capture the capabilities of data dissemination techniques used in such networks. Moreover, we survey relevant data dissemination techniques and analyze them using the proposed taxonomy. In this we analyze existing work in the area of data dissemination in opportunistic networks. We analyze dif- ferent collaboration-based communication solutions, em- phasizing their capabilities to opportunistically dissemi- nate data. We present the advantages and disadvantages of the analyzed solutions. Furthermore, we propose the categories of a taxonomy that captures the capabilities of data dissemination techniques used in opportunistic net- works. Using the categories of the proposed taxonomy, we also present a critical analysis of four opportunistic data dissemination solutions. To our knowledge, a classication of data dissemination techniques has never been previously proposed.
Personal computing devices, such as smart-phones and PDAs, are commonplace, bundle several wireless network interfaces, can support compute intensive tasks, and are equipped with powerful means to produce multimedia content. Thus, they provide the resources for what we envision as a human pervasive network: a network formed by user devices, suitable to convey to users rich multimedia content and services according to their interests and needs. Similar to opportunistic networks, where the communication is built on connectivity opportunities, we envisage a network above these resources that joins together features of traditional pervasive networks and opportunistic networks fostering a new computing paradigm: opportunistic computing. In this article we discuss the evolution from opportunistic networking to opportunistic computing; we survey key recent achievements in opportunistic networking, and describe the main concepts and challenges of opportunistic computing. We finally envision further possible scenarios and functionalities to make opportunistic computing a key player in the next-generation Internet.