Representing & Querying Temporal Workflow Schemas

Abstract Workflows are activities involving the co-ordinated execution of multiple tasks performed by entities, in the enterprise environment. Workflow systems support the encoding and execution of workflows. A workflow management system is proposed, in which a considerable attention is paid on the utilisation of the services provided by the underlying flexible database formalism. Flexible database formalisms must permit the modelling of trends, seasonality (periodicity), cyclic variations of trends and irregular activities (no predictable patterns) in the enterprise environment This paper will be restricted in workflow management system design, and activity scheduling, in a post relational environment whereas relational operators, utilise paths (links between domains), in order to express interdependencies between activities. Keywords : Temporal Activities, Time Model, Temporal Activities, and Temporal Workflows 1. INTRODUCTION Workflow Management systems improve business process by integrating information, from more than one domains, directly or indirectly related with a specific enterprise function. In a non-stable and changing business environment, there is a critical need to become more competitive, by controlling the flow of information throughout the enterprise in a timely manner. Many business activities have restrictions such as a constrained duration, dates of resubmission, maximum and minimum duration of an activity. Typically time violations increase the cost of a business function, because they introduce some kind of exception handling [1]. Existing workflow management systems offer limited support for management and representation of activities with constrained or infinite duration. The latter includes periodical and recurring activities [2] with either known or known unknown frequency of reoccurrence. Therefore a workflow management system should provide information about an activity, its calendric restrictions, and the time requirements about the activity. This paper presents a temporal post relational environment that utilises the concept of lattices and hierarchies for the support of the major components defined within a workflow environment. In representing activities, encoding seasonality and trends a temporal model and representation at the database level is required and thus is proposed. The way that parallel and conditionally executed activities are related through the dimension of time, is defined and presented.