CSS 496 Business Process Re-engineering for BS(CS)

1. CSS 496 Business Process Re-engineering for BS(CS) Chapter 3: Enterprise modeling Khurram Shahzad mks@ciitlahore.edu.pk Based on Petia, Marlon, Aalst and Weske Lectures

2. Enterprise Resource Planning • ERP definition • Software solution that addresses the enterprise needs taking the process view of an organisation to meet the organisational goals tightly integrating all functions of an enterprise • ERP means integration of • Processes • Databases • Tools • Applications • Interfaces

3. Enterprise Resource Planning • Drawback of ERP • Costly implementation • Dependency on vendor • Forgoing “best-of-breed” solutions • Solution: EAI • Enterprise Application Integration (EAI) is “the unrestricted sharing of data and business processes among any connected applications and data sources in the enterprise”.

4. Architectures of EAI Message Broker Process Broker Point to Point

5. Goal Modeling • How to make the goals of an enterprise explicit • Purpose of Goal Modeling • Describing the goals of an enterprise • Showing how the goals are interrelated • Finding problems that hinder goal fulfillment • Finding opportunities that facilitate goal fulfillment

6. Components of a Goal Model

7. An Example

8. An Example

9. A Goal Model for a Library

10. Goal Decomposition

11. Goal Decomposition

12. An Example • Per runs a campaign for president. His main opponent is Eva. Construct a goal model for the following: • Victory in the election • Get support from EU supporters • Get support from EU critics • Make the opponent look dishonourable • Per has misused credit cards • Eva has misused credit cards • Get many TV commercials • The budget is limited • Get financial support from big business • Get an image as independent • Get an image as trustworthy

13. Solution

14. Process Modeling • Purpose of Process Modeling

15. Basic Workflow Concepts • Task - a logical unit of work that is carried out as a single whole • Resource - a person or a machine that can perform specific tasks • Activity - the performance of a task by a a resource • Case - a sequence of activities performed to achieve some goal, an order, an insurance claim, a car assembly • Work item - the combination of a case and a task that is just to be carried out • Process - describes how a particular category of cases shall be managed • Control flow construct - sequence, selection, iteration, parallelisation

16. Process Modeling • Focus on • Petri Nets • BPMN • EPC

17. Petri Nets • Petri Nets – a formal approach based upon an established formalism for the modeling and analysis of processes • Advantages • It forces precise definitions • Ambiguities, uncertainties, and contradictions are thus prevented, in contrast to many informal diagramming techniques • Formalism often enables the use of number of analytical techniques

18. Petri Nets • Classic Petri nets • Simple process model • Just three elements: places, transitions and arcs. • Graphical and mathematical description. • Formal semantics and allows for analysis.

19. Petri Nets • A Petri nets consists of places and transitions • Places are indicated by a circle • A transition is shown as a rectangle

20. Petri Nets • Rules • Connections are directed. • No connections between two places or two transitions. • Places may hold zero or more tokens. • First, we consider the case of at most one arc between two nodes.

21. Petri Nets • Enabled • A transition is enabled if each of its input places contains at least one token. enabled Not enabled Not enabled

22. Petri Nets • Firing • An enabled transition can fire (i.e., it occurs). • When it fires it consumes a token from each input place and produces a token for each output place. fired

23. Petri Nets • Example

24. Petri Nets • Enabled Transition • A transition is enabled when there is token in each of its input places

25. Petri Nets • Traffic Light Example

26. Petri Nets • Traffic Light Example

27. Petri Nets • Traffic Light Example

28. Petri Nets • Two traffic light

29. Colored Petri Nets

30. Petri Nets with Time • Every token gets a timestamp, indicating the time from which the token is available • A transition is enabled when each token to be consumed has a timestamp equal or prior to the current time • Each transition gives a delay to a token produced by the transition.

31. Traffic Lights with Time

32. Swimming School Exercise

33. Basic Workflow Concepts • Task - a logical unit of work that is carried out as a single whole • Resource - a person or a machine that can perform specific tasks • Activity - the performance of a task by a a resource • Case - a sequence of activities performed to achieve some goal, an order, an insurance claim, a car assembly • Work item - the combination of a case and a task that is just to be carried out • Process - describes how a particular category of cases shall be managed • Control flow construct - sequence, selection, iteration, parallelisation

34. Workflow Concepts in Petri Nets • Task - transition • Resource - token • Activity - transition that fires • Case - token • Work item - enabled transition • Process - Petri net • Control flow construct - modelled by places and transitions

35. Swimming School Exercise

36. Workflow Analysis • Types of Analysis • Qualitative (correctness) • Deadlock • Livelock • … • Quantitative (performance) • Average completion time • Level of service • …

37. Reachability Analysis

38. Reachability Analysis

39. Reachability Analysis

40. Reachability Analysis

41. Reachability Graph Exercies

42. Quantitative Analysis • Resource utilization • Number of cases in progress • Waiting time • System time

43. Resource utilization • Consider a process with one task • Number of cases in progress • λ is the number of incoming cases per time unit • µ is the number of cases the resource is able to process per time unit • The resource utilization is • ρ = λ / µ

44. Resource utilization λ = 4 µ = 5 The resource utilisation is ρ = λ / µ = 4 / 5 = 0.8

45. Slides 6 from Paul Johannesson