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An important class of problems is related to performing activities, and the planning of future activity. The “doing of things” is at the heart of human endeavour. The WWW has primarily concentrated to date on information storage and retrieval, and the data models and standards mostly relate to such things. More emphasis should now be placed on modelling activity and the collaboration between human and system agents that can be conducted through the WWW.

The planning and process modelling communities have started to develop shared models and ontologies to represent activities, tasks, agent capabilities, constraints etc. These might form the generic core of a shared ontology to support the movement of information about activities over the WWW.

The paper describes some work on producing collaborative, multi-agent systems with a mix of human and software agents engaging in planning and plan and execution support over the WWW. The work includes O-Plan, Process Panels and I-X. The underlying process ontology constraint model of activity and the more general constraint model of synthesised artefacts are described. These could provide a robust conceptual model to underlie future web standards for describing task achieving agents on the web and their behaviours.