Crowdsourcing tasks to social networks in BPEL4People

Human-interactions are a substantial part of today's business processes. In service-oriented systems this has led to specifications such as WS-HumanTask and BPEL4People which aim at standardizing the interaction protocol between software processes and humans. These specifications received considerable attention from major industry players due to their extensibility and interoperability. Recently, crowdsourcing has emerged as a new paradigm for leveraging a human workforce using Web technologies. We argue that crowdsourcing techniques and platforms could benefit from XML-based standards such as WS-HumanTask and BPEL4People as these specifications allow for extensibility and cross-platform operation. However, most efforts to model human interactions using BPEL4People focus on relatively static role models for selecting the right person to interact with. Thus, BPEL4People is not well suited for specifying and executing processes involving crowdsourcing of tasks to online communities. Here, we extend BPEL4People with non-functional properties that allow to cope with the inherent dynamics of crowdsourcing processes. Such properties include human capabilities and the level of skills. We discuss the formation of social networks that are particularly beneficial for processing extended BPEL4People tasks. Furthermore, we present novel approaches for the automated assignment of tasks to a social group. The feasibility of our approach is shown through a proof of concept implementation of various concepts as well as simulations and experiments to evaluate our ranking and selection approach.