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Principle 6 – Actions are chosen contextually: A repertoire of actions and oper-
ations is created, maintained, and made available to any activity, which may be
performed by making contextual choices from the repertoire.
Principle 7 – Actions are understood contextually: The immediate goal of an
action may not be identical to the objective of the activity of which the action is a
component. It is enough to have an understanding of the overall objective of the
activity to motivate successful execution of an action.
Principle 8 – Plans guide work: A plan is not a blueprint or prescription of work
to be performed, but merely a guide, which is modified depending on context
during the execution of the work.
Principle 9 – Exceptions have value: Exceptions are merely deviations from
a preconceived plan. Deviations will occur with almost every execution of the
plan, and give rise to a learning experience, which can then be incorporated into
future executions.
Principle 10 – Granularity based on perspective: A particular piece of work
might be an activity or an action depending on the perspective of the viewer.
Activity Theory offers a number of interesting insights into workflow research
domains, particularly the related issues of workflow adaptability, flexibility, evo-
lution, and exception handling. The derived principles above have formed the
theoretical foundations for the implementation and deployment of the Worklet Ser-
vice. Activity Theory was chosen as the theoretical framework because it provides,
as demonstrated in this section, a tight fit between actual work practices and the
requirements of PAIS designed to support them. This section does not claim Activ-
ity Theory to be the only applicable theoretical framework, but merely one from
which sound principles of work practice for adaptive business processes could be
derived.

4.4 Conceptualization of Worklets

The consideration of the derived principles of Activity Theory formed the concep-
tual foundations of the Worklet Service, a discrete service that transforms otherwise
static workflow processes into fully flexible and dynamically extensible process
instances that are also supported by dynamic exception handling capabilities (cf.
Chap. 5). This chapter represents a conceptual view of the Worklet Service; the
implementation and use of the service is described in detail in Chap. 11.
Fundamentally, a workflow management system that is based on the principles
derived from Activity Theory would satisfy the following criteria:
A flexible modeling framework: a process model is to be regarded as a guide to
an activity’s objective, rather than a prescription for it
A repertoire of actions: extensible at any time, the repertoire would be made
available for each task during each execution instance of a process model