Business processes, the next-generation workflows, have attracted considerable research interest in the last 15 years. More recently, several XML-based languages have been proposed for specifying and orchestrating business processes,resultingintheWS-BPELlanguage.EvenifWS-BPELhasbeendevelopedtospecifyautomatedbusiness processes that orchestrate activities of multiple Web services, there are many applications and situations requiring that people be considered as additional participants who can influence the execution of a process. Significant omissions from WS-BPEL are the specification of activities that require interactions with humans to be completed, called human activities, and the specification of authorization information associating users with human activities in a WS-BPEL business process and authorization constraints, such as separation of duty, on the execution of human activities. In this article, we address these deficiencies by introducing a new type of WS-BPEL activity to...