Context-aware workflow management in eHealth applications

Workflows are a technology to structure work in functional, non-overlapping steps. They define
not only the order of execution of the steps, and describe whether steps are executed in
parallel, they also specify who or what tool has to fulfill which step. Workflows offer the possibility
to automate work, to increase the understandability of processes, and they ease the
control of process execution. The tools to manage workflows, so called workflow management
systems (WfMSs), are traditionally rigid as they separate workflow definition done at build time
from workflow execution done at run time. This makes them ill-suited for managing flexible and
unstructured workflows. In this thesis, we focus on the support of flexible processes in eHealth,
which are affected by more foreseen than unforeseen events. To bridge the gap between rigid
WfMSs and flexible workflows, we developed a concept for dynamic and context-aware workflow
management called Flexwoman. Although our focus lies on flexible eHealth processes,
Flexwoman is a generic approach that can be applied to several different application domains.
Flexwoman supports the usage of context information to adapt processes automatically at run
time to foreseen events. Processes can also be manually adapted to handle unforeseen events.
To achieve this flexibility, context information from different sensors is unified and thus can be
analyzed in the same way. The analysis and adaptation of workflows is executed with a rule engine.
A rule engine can store, reason about and apply knowledge automatically and efficiently.
Rules and application logic are separated, thus, rules can be changed during run time without
affecting application logic or process description. Workflows are internally described by Hierarchical
Colored Petri nets (HCPNs) and executed by a HCPN execution engine. HCPNs allow for
a deterministic execution of workflows and can represent workflows on different levels of detail.
In summary, in Flexwoman, significant context changes (events) trigger automated adaptations
that replace parts of the workflow by sub workflows, which can in turn be adapted. The adaptations
and the rules for context-aware adaptation are saved in the organizational memory for
later reuse. Flexwoman’s event based behavior facilitates proactive adaptations instead of only
allowing for adaptations while entering or leaving a task. Replacements are not bound to special
places defined at build time but each part of the workflow, which has not been executed yet, can
be replaced at run time. We implemented and evaluated the concept. The evaluations show
i) that all required functionality is available, ii) that the system scales with a growing number of
rules, and iii) that the system correctly handles failure situations.