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

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

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”.

Architectures of EAI Message Broker Process Broker Point to Point

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

Components of a Goal Model

An Example

An Example

A Goal Model for a Library

Goal Decomposition

Goal Decomposition

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

Solution

Process Modeling Purpose of Process Modeling

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

Process Modeling Focus on Petri Nets BPMN EPC

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

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.

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

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.

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

Petri Nets Firing fired 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

Petri Nets Example

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

Petri Nets Traffic Light Example

Petri Nets Traffic Light Example

Petri Nets Traffic Light Example

Petri Nets Two traffic light

Colored Petri Nets

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.

Traffic Lights with Time

Swimming School Exercise

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

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

Swimming School Exercise

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

Reachability Analysis

Reachability Analysis

Reachability Analysis

Reachability Analysis

Reachability Graph Exercies

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

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

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

Slides 6 from Paul Johannesson