presented by Barbara Weber Parts of this research was funded by the Austrian Science Fund (FWF): P23699-N23.

Overcoming the challenges of reuse in

large process model repositories

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Agenda

Motivation Process of Process Modeling Supporting the Process of Process Modeling Refactoring Test driven Modeling Literate Process Modeling

Summary

MOTIVATION quality of process models as a necessary precondition for reuse

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Reuse of Common Process Knowledge

Increasing adoption of process-aware information systems

Emergence of large process model repositories often comprising a large number of related process fragments

Reuse of common process knowledge to reduce process modeling and maintenance efforts

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Quality Problems

Error rates between 10% and 50% in industrial process model collections (Mendling 2009, Mendling et al. 2008)

Impedes comprehensibility and maintainability of process models (Mendling 2008, Weber & Reichert 2008, Weber et al. 2011)

o Non intention-revealing or inconsistent naming (Mendling et al. 2010)

o Redundant process fragments (Hallerbach et al. 2010)

o Large and unnecessarily complex process models (Soto et al. 2008)

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Quality Problems

Error rates between 10% and 50% in industrial process model collections (Mendling 2009, Mendling et al. 2008)

Impedes comprehensibility and maintainability of process models (Mendling 2008, Weber & Reichert 2008, Weber et al. 2011)

o Non intention-revealing or inconsistent naming (Mendling et al. 2010)

o Redundant process fragments (Hallerbach et al. 2010)

o Large and unnecessarily complex process models (Soto et al. 2008)

THE PROCESS OF PROCESS MODELING

how does the process of creating, modifying, and reusing process models look like

Process of Process Modeling (PPM) • Iterative, highly flexible process • Depends on individual modeler • 3 successive phases

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Comprehension

Modeling Reconciliation (Pinggera et al. 2010, Pinggera et al. 2011, Pinggera et al. 2012)

• Understand requirements • Understand existing process model • Understand components for reuse • Chunking (Cant et al. 1995)

– Understanding in chunks (group of information)

Process of Process Modeling Comprehension

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Comprehension

Modeling Reconciliation

• Central Concept: Working Memory • Required by all conscious mental activities • Severely limited: 7 +/- 2 information „slots“ (Miller 1956) • Mental effort: utilization of working memory (Paas et al.

2003) • Overflow: rapid performance decrease! (Sweller 1988)

Process of Process Modeling Comprehension

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Comprehension

Modeling Reconciliation

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• Abstraction o hiding of irrelevant information (Parnas 1972) o supports human mind’s attention management (Larking

and Simon 1987) • Split-attention effect (Sweller and Chandler 1994)

o occurs when information from several sources needs to be integrated

o switching attention between models

Process of Process Modeling Comprehension

Comprehension

Modeling Reconciliation

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• External memory o mechanism for reducing mental effort o Information storage outside the human cognitive system

(e.g., pencil and paper or a blackboard)

• Cognitive Trace o Information taken from working memory and stored in an

external memory (e.g., to mark, update, and highlight information)

Process of Process Modeling Comprehension

Comprehension

Modeling Reconciliation

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• comprehended chunks are formalized in process model – by creating new model elements – by integrating reusable components

• varying number of modeling steps

Process of Process Modeling Modeling

Comprehension

Modeling Reconciliation

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• improve understandability – reorganize model (refactor) – utilize secondary notation, typographic cues

• facilitate next comprehension phase

Process of Process Modeling Reconciliation

Comprehension

Modeling Reconciliation

REFACTORING fostering reusability of large process model repositories

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• Improving model quality without changing the observable behavior of the model

Process Model Refactoring Reconciliation Support Fostering Reuse

Comprehension

Modeling Reconciliation

(Weber and Reichert 2008, Weber et al. 2011) 03.09.2012 17

Typical Process Model Smells PMS1: Non-intention Revealing Naming of Activities / Process Model

PMS2: Contrived Complexity

PMS3: Redundant Process Fragment

PMS4: Large Process Models

PMS5: Lazy Process Models

PMS6: Unused Branches

PMS7: Frequently Occurring Instance Changes

PMS8: Frequently Occurring Variant Changes

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Identification of Process Model Smells

Application of Refactoring Techniques

RF1: Rename Activity

RF2: Rename Process Schema

RF3: Substitute Process Fragment

RF4: Extract Process Fragment

RF5: Replace Process Fragment by Reference

RF6: Inline Process Fragment

RF7: Re-label Collection

RF8: Remove Redundancies

RF9: Generalize Variant Change

RF10: Remove Unused Branches

RF11: Pull Up Instance Change 19

Process Model Refactorings

(Weber and Reichert 2008, Weber et al. 2011)

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Labeling of Process Models

• PMS1. Non intention revealing naming of activities / process models

o Ambiguous or non intention revealing labels

o Inconsistent use of labeling styles

(Weber et al. 2011)

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Number of ways students name an activity in a process model • Insights from a process modeling experiment

with 113 students.

• The following sentence in the process description resulted into 84 different ways for naming this particular activity:

“Afterwards the scouting team attends games of the player they are interested in live in the football stadium.”

(Fahland 2012)

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Inconsistent Names and Labeling Styles • Repository with 70 process models from healthcare • 16 out of 70 process models contained activities

regarding the scheduling of medical procedures (e.g., surgeries, medical examinations, drug administration)

• Although activities had similar intentions, different labels and labeling styles were used o “Make appointment”, “appointment”, “schedule examination”,

“fix day”, “agree on surgery date”, “plan”

(Weber et al. 2011)

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Labeling Conventions + Refactoring of Labels • Usage of labeling conventions and domain thesauri (Becker et al. 2009)

• Technique for automatically refactoring from action-noun style to labels in verb-object style

(Leopold, Smirnov, and Mendling 2012)

• Activities with similar labels provide potential refactoring opportunities

(Dijkman et al. 2011)

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Redundant Process Fragments Candidates for Reuse • PMS3: Redundant Process Fragments

o Redundant process fragments can be commonly found in existing process models

(Weber et al. 2011)

o More than 560 clones in the SAP reference model (Dumas et al. 20xx)

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Extracting Sub Processes • Method for automatically detecting exact clones,

which can be extracted to sub processes (Dumas et al. 20xx)

Similar process fragments as potential refactoring opportunities (Dijkman et al. 2011) o Exact matches o Similar fragments, whereby some activities

only appear in one fragment o Same activities, but different business objects

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Extracting Sub Processes • Method for automatically detecting exact clones,

which can be extracted to sub processes (Dumas et al. 20xx)

Similar process fragments as potential refactoring opportunities (Dijkman et al. 2011) o Exact matches o Similar fragments, whereby some activities

only appear in one fragment o Same activities, but different business objects

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Large Process Models are Difficult to Understand, Maintain, and to Reuse • PMS4: Large Process Models

o Process models with several hundred activities are not

uncommon (Soto et al. 2008)

o Large process models tend to comprise more formal flaws than smaller ones (Mendling et al. 2008)

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Automatically Extracting Sub processes • Method for automatic modularization of business

process models (Reijers et al. 2011)

• Method for the automatic labeling of process models (Leopold et al. 2011)

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Automatically Extracting Sub processes • Method for automatic modularization of business

process models (Reijers et al. 2011)

• Method for the automatic labeling of process models (Leopold et al. 2011)

TEST DRIVEN MODELING fostering understandability, maintainability, and reuse of declarative processes

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• Is the model really doing what it is expected to do?

Test Driven Modeling Comprehension Support Fostering Reuse

Comprehension

Modeling Reconciliation

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Interactions between Constraints Make Declarative Processes Difficult to Understand

Must be executed at least once

Must be first activity executed

Activity

Complete paper writing must be executed before Format to instructions

Must be executed once

Get acceptance must not be followed by Work on revision

Each execution of write response letter must be preceded by read reviews for revising paper

(Zugal et al. 2012b)

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Interactions between Constraints Make Declarative Processes Difficult to Understand

Must be executed at least once

Must be first activity executed

Activity

Complete paper writing must be executed before Format to instructions

Must be executed once

Get acceptance must not be followed by Work on revision

Each execution of write response letter must be preceded by read reviews for revising paper

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Interactions between Constraints Make Declarative Processes Difficult to Understand

Must be executed at least once

Must be first activity executed

Activity

Complete paper writing must be executed before Format to instructions

Must be executed once

Get acceptance must not be followed by Work on revision

Each execution of write response letter must be preceded by read reviews for revising paper

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Test Driven Modeling

Central Concept Test Cases: allows to

specify behavior the process model must exhibit or prohibit Test Case consist of

Execution Trace (1) Set of assertions (2), (3), (4)

(Zugal et al. 2012a)

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Test Driven Modeling Suite

(Zugal et al. 2012a)

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Test Driven Modeling

Makes information explicit that is only implicit in the process model, thus fostering understandability by supporting computational offloading

Allows for testing execution traces in an automated way

Test cases constitute an executable documentation

Reduces mental effort, speeds up changes, and reduces errors (Zugal et al. 2011, Zugal et al. 2012c)

LITERATE PROCESS MODELING

fostering understandability, maintainability and reuse by intervening text and model

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• What is the model doing and why have certain design decisions been taken?

Literate Process Modeling Comprehension Support Fostering Reuse

Comprehension

Modeling Reconciliation

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Literate Process Modeling

Supports domain experts and system analysts during model comprehension by flexibly interlinking textual descriptions and formal process model Fosters model understandability Provides a documentation of the process model Facilitates model comprehension as well as

model changes by documenting design decisions

(Pinggera et al. 2012b)

(Pinggera et al. 2012b) 41

Literate Process Modeling

SUMMARY

wrap up

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Conclusions

• Quality a necessary precondition for reuse • Creating, maintaining, and reusing process fragments

is a process in itself, which requires support

Comprehension

Modeling Reconciliation Process Model Refactoring

Test Driven Modeling Literate Process Modeling

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