Verification of SAP reference models - LORIA · 1)The EPC is correct, i.e. it is always possible to execute the process without ending up in some undesired state. 2)The EPC is incorrect,

Boudewijn van Dongen

Monique Jansen-Vullers

Verification of SAP reference models

www.processmining.org

Verification of SAP reference models

1) Motivation

2) SAP Reference Models

3) EPC verification process

4) Results

5) Conclusions


Reference Models

Definition

Generic conceptual models that formalise recommended practices for a certain

domain (Fettke and Loos, 2003)

Supports software development, -selection and –configuration, education and

process (re)design

A correct reference model is extremely important!


SAP Reference Models

Enterprise Resource Planning software

Supporting (almost) all business processes

World Market leader

Reference models available in ARIS for MySAP

Modeled in EPCs (informal semantics)


Verification of Process Models

Process models with formal semantics

Model is correct

Model is incorrect

Process models with informal semantics

Formal executable semantics for an informal model

Alternative:

The designer decides semantically correctness


Verification Process

Starting point

Informal modelling language

Process designer has deep knowledge of the process under consideration

Process model is not intended for use on an execution level

Verify the EPC in the ProM Framework

– Export from ARIS for MySAP

– Import in the ProM Framework


Verification in the ProM Framework

Based on graph reduction techniques

The designer decides which combinations of initial events could initiate the process

The ProM Tool calculates events which are dealt with or not

The designer decides which outcomes are desirable or not

This set can be empty

Iterative process


1) The EPC is correct, i.e. it is always possible to execute the process without

ending up in some undesired state.

2) The EPC is incorrect, i.e. there is some part of the EPC that cannot be executed

without running into some undesired behaviour.

3) The EPC may execute correctly, i.e. the EPC

can be executed, but special care has to be

taken to make sure that an execution does not

produce some undesired result.

A B

e2

e5

e4

e3 XX

/\

/\

C D

e1

/\

Result of the verification process



Further steps

Explaining result in terms of the original EPC and acting on it should be

done by the designer again

If the EPC is not correct and executable, there are three options:

1) Redefine the possible sets of initial events

2) Reconsider the acceptable sets of final events

3) Accept the EPC as it is, since it is not intended to be an executable specification

If the EPC is incorrect, a pointer is given to the area where the problem occurs.


Results: Procurement module (40 submodels)

Correct models: 36

Incorrect models: 2

– Internal procurement

– Procurement via subcontracting

May be correct models: 2

– Materials and external services

– Outline purchase agreements

Most errors in the higher level models!





Results: Guided model selection

Most errors in the higher level models, and occur frequently

1. Initial event(s) applied in several (sub)modules

Sometimes joined by XOR

Sometimes joined by AND




Results: Guided model selection

Most errors in the higher level models, and occur frequently

Initial event applied in several (sub)modules

Sometimes joined by XOR

Sometimes joined by AND

2. Reuse of parts of models




Conclusions

Only a few problems in low level models

Many problems in high level models

Errors, if found, are easily repaired

Verification tools help to create correct reference models

Thank you for your attention

Documents

Verification of SAP reference models - LORIA · 1)The EPC is correct, i.e. it is always possible to execute the process without ending up in some undesired state. 2)The EPC is incorrect,