Sira Yongchareon1, Chengfei Liu1, and Xiaohui Zhao2

1Faculty of Information & Communication Technologies

Swinburne University of Technology, Australia2Faculty of Creative Industries and Business

Unitec Institute of Technology, New Zealand

An Artifact-centric View-based Approach to Modeling Inter-organizational Business Processes

WISE’11, 12-14 October 2011, Sydney, Australia

WISE’11, 12-14 October 2011, Sydney, Australia Sira Yongchareon, Chengfei Liu, and Xiaohui Zhao 2

Introduction & Related works Motivation & Issues Artifact-centric Collaboration Model (ACC model)

ACC Construction method – a view-based approach ACC Verification Changes and Validation

Conclusion

Outline

WISE’11, 12-14 October 2011, Sydney, Australia Sira Yongchareon, Chengfei Liu, and Xiaohui Zhao 3

Inter-organizational workflows

Introduction : Inter-org workflows

Taken from Chebbi, I, et al. Data & Knowledge Engineering 56 (2006)

WISE’11, 12-14 October 2011, Sydney, Australia Sira Yongchareon, Chengfei Liu, and Xiaohui Zhao 4

Public view can be used to facilitate the inter-org coordination

Introduction : Inter-org workflows

Taken from Chebbi, I, et al. Data & Knowledge Engineering 56 (2006)

WISE’11, 12-14 October 2011, Sydney, Australia Sira Yongchareon, Chengfei Liu, and Xiaohui Zhao 5

Process view framework for (traditional) inter-org workflow management

Introduction : Inter-org workflows

From Jiang, P, et al. Advanced Engineering Informatics 24 (2010)

WISE’11, 12-14 October 2011, Sydney, Australia Sira Yongchareon, Chengfei Liu, and Xiaohui Zhao 6

Issues on current task-based approaches Process still inflexible? Due to procedural nature of task-based model

(and contract) How to ensure that the changes can preserve both local and global goals? Contract not formed by goals of all participants, but their task interactions

Data related issues? Due to lack of holistic view of data in the model Most control decisions made based on “data” How to preserve the

integrity and consistency of data effected by the change of tasks? How key data interested by business stakeholders can be modelled and

monitored?

Artifact-centric workflow modeling an emerging and promising approach that can tackle those issues

Introduction : An emerging approach

WISE’11, 12-14 October 2011, Sydney, Australia Sira Yongchareon, Chengfei Liu, and Xiaohui Zhao 7

Introduction : Artifact-centric model Business Artifacts and their lifecycle – Purchasing

process example The purchasing process starts when a buyer places a purchase order

to a supplier for particular products and it ends when the buyer pays an invoice.

The shipping process starts when the supplier requests a logistic to create a shipping order and it ends when the items arrives to the buyer

WISE’11, 12-14 October 2011, Sydney, Australia Sira Yongchareon, Chengfei Liu, and Xiaohui Zhao 8

Introduction : How they glued together Business rules – to associate artifacts and tasks

sync rule

WISE’11, 12-14 October 2011, Sydney, Australia Sira Yongchareon, Chengfei Liu, and Xiaohui Zhao 9

Introduction : High-level framework 4-Dimensional Framework for Artifact-Centric Business

Process Modeling (Hull, R., CoopIS 2008)

Business artifacts Macro Lifecycles Services (Tasks) Associations

WISE’11, 12-14 October 2011, Sydney, Australia Sira Yongchareon, Chengfei Liu, and Xiaohui Zhao 10

Introduction : Artifacts in inter-org Business Artifacts in the inter-org processes

Local artifact – involved in a single org (cross-department is possible) Shared artifact – involved cross-organizational process Part of a “message

” passing between orgs? What are the “concerns” in the collaborative environment?

Flexibility Need to allow organization to freely change and implement its own responsible part of the collaboration

Autonomy Changes can be done locally and privately without revealing any private parts to others

Compliance Changes made to the private parts conform to the “agreed contract” and do not interfere the overall process

WISE’11, 12-14 October 2011, Sydney, Australia Sira Yongchareon, Chengfei Liu, and Xiaohui Zhao 11

Issues and challenges? How to define/model inter-org processes by using

artifact-centric modeling approach How to guarantee a desired behavior of inter-org

processes How to validate changes occurring within local

processes but may impact the overall collaboration

WISE’11, 12-14 October 2011, Sydney, Australia Sira Yongchareon, Chengfei Liu, and Xiaohui Zhao 12

From Private view to Public view to “Service Contract”

To achieve high-degree of autonomy, flexibility, and compliance of inter-org processes

Process view approach

Taken from van der Aalst, W.M.P., et al. The Computer Journal 53(1) (2010)

WISE’11, 12-14 October 2011, Sydney, Australia Sira Yongchareon, Chengfei Liu, and Xiaohui Zhao 13

Construct private view – a complete (concrete) local process owned by each individual organization

Construct public view of local process – an abstracted version of private view that is publicly visible to every organization By applying state condensation technique on the lifecycle of artifact

(Yongchareon, S. et al., CoopIS 2010)

Construct ACC model - an integration of all views in the collaboration

Construction method

WISE’11, 12-14 October 2011, Sydney, Australia Sira Yongchareon, Chengfei Liu, and Xiaohui Zhao 14

Private/Public view construction - Running example. Purchasing process consists of three core artifacts: Purchase Order, Shipping Order, and Invoice

The purchasing process starts when a buyer places a purchase order to a supplier for particular products and it ends when the buyer pays an invoice.

The shipping process starts when the supplier requests a logistic to create a shipping order and it ends when the items arrives to the buyer

Construction method

WISE’11, 12-14 October 2011, Sydney, Australia Sira Yongchareon, Chengfei Liu, and Xiaohui Zhao 15

Private/Public view construction – Buyer’s view Buyer’s private process consists of Purchase Order, Quote, and Invoice

artifacts

Purchase Order and Invoice are shared artifacts Quote is local artifact (belong only to Buyer’s local process)

Construction method

Synchronization dependency

Private-to-public view abstraction we denote it as p(buyer)

WISE’11, 12-14 October 2011, Sydney, Australia Sira Yongchareon, Chengfei Liu, and Xiaohui Zhao 16

Private/Public view construction – Supplier’s view Supplier’s private process consists of Purchase Order, Picking List,

Shipping Order, and Invoice artifacts

Notice changes in Purchase Order Buyer’s local part disappear

Construction method

Buyer’s view

Buyer’s view

WISE’11, 12-14 October 2011, Sydney, Australia Sira Yongchareon, Chengfei Liu, and Xiaohui Zhao 17

Private/Public view construction – Logistics’ view Logistics' private process consists of Purchase Order, Shipping List,

and Shipping Order artifacts

Notice NO Invoice artifact

Construction method

WISE’11, 12-14 October 2011, Sydney, Australia Sira Yongchareon, Chengfei Liu, and Xiaohui Zhao 18

Private ACC Model Construction Integrate private view of each organization in the collaboration

Construction method

v buyer + v supplier+ v logistics= v ACC

WISE’11, 12-14 October 2011, Sydney, Australia Sira Yongchareon, Chengfei Liu, and Xiaohui Zhao 19

Public ACC Model Construction Integrate public view of each organization in the collaboration

Construction method

p(v buyer ) + p(v supplier ) + p(v logistics ) = p(v ACC )

WISE’11, 12-14 October 2011, Sydney, Australia Sira Yongchareon, Chengfei Liu, and Xiaohui Zhao 20

Model verification Traditional compositional model verification approach

can be used for the behavior verification of ACC model (e.g., LIND-NIELSEN, J., Formal Methods in System Design 2001)

“soundness” guarantee the desired and correct behavior of overall process

Local soundness vs. Global soundness Local soundness soundness of individual private view Global soundness soundness of ACC model

WISE’11, 12-14 October 2011, Sydney, Australia Sira Yongchareon, Chengfei Liu, and Xiaohui Zhao 21

Model verification Artifact lifecycle and ACC lifecycle

1) Artifact lifecycle generated by interpreting BRs

2) ACC lifecycle generated by using compositional technique

WISE’11, 12-14 October 2011, Sydney, Australia Sira Yongchareon, Chengfei Liu, and Xiaohui Zhao 22

Model verification Given two lifecycles, we can compose them into new

composed lifecycle

There inference rules for combined transition formation

LC = L(C1) Å L(C2)L(C2)L(C1)

s1 s2 s3 s4

s1, s3 s2, s3 s2, s4r1 [C2.s3]

r3 [C2.s4 Ù C3.s5]

r2 [C1.s2]

r3 [C4.s6] r1 r2

r3 [C3.s5 Ù -C4.s6]init initinit, init

s1, s4

r3 [-C3.s5 Ù C4.s6]

r3 [C3.s5 Ù C4.s6]r3 [C4.s6]

WISE’11, 12-14 October 2011, Sydney, Australia Sira Yongchareon, Chengfei Liu, and Xiaohui Zhao 23

Model verification Lifecycle of ACC is “sound” if it is:

safe for every business rule r in ACC, r induces one and only one

transition

and goal-reachableFor every state s in ACC, there exists final state sf in ACC such that

s is reachable from the initial state and sf is reachable from s

For every final state sf in ACC, sf is reachable from the initial state

WISE’11, 12-14 October 2011, Sydney, Australia Sira Yongchareon, Chengfei Liu, and Xiaohui Zhao 24

Process changes Changes can be made locally on the private view

Refinement Replace states or a transition of shared artifact with new sub-lifecycle (called Lifecycle fragment or L-fragment)

Lifecycle refinement and synchronization refinement

Extension Add new local artifact(s) with the synchronization to some existing artifact in the process

WISE’11, 12-14 October 2011, Sydney, Australia Sira Yongchareon, Chengfei Liu, and Xiaohui Zhao 25

Process changes Examples of changes in process

Several possible ways of refinement with extension

WISE’11, 12-14 October 2011, Sydney, Australia Sira Yongchareon, Chengfei Liu, and Xiaohui Zhao 26

Process changes Issues?

How to guarantee valid changes the result of refinement/extension preserves the global soundness of the collaboration

Compositional model verification Unrealistic to access local artifacts owned by other organizations Is expensive and leads to state exposition problem

We propose to validate the process locally but can assert global soundness, i.e., Validating individual private view based on local modification

WISE’11, 12-14 October 2011, Sydney, Australia Sira Yongchareon, Chengfei Liu, and Xiaohui Zhao 27

Process changes : Validation Change Validation Framework “View conformance”

(covers)

conforms to

WISE’11, 12-14 October 2011, Sydney, Australia Sira Yongchareon, Chengfei Liu, and Xiaohui Zhao 28

Process changes : Validation The modified private view must be behavioral-

consistent to its original private view Consistency checking by lifecycle coverage checking

(a) is public view and (b), (c), and (d) are private views of (a) with lifecycle modification

(a) is covered by (c) and (d), but not (b) (c) and (d) are consistent to (a)

Notice this is observation consistency

WISE’11, 12-14 October 2011, Sydney, Australia Sira Yongchareon, Chengfei Liu, and Xiaohui Zhao 29

ACC Model : Validating changes Key questions….

How to ensure that changes make a modified private view consistent to its original view?

We need to guarantee that every change is valid by imposing construction rules on both “refinement” and “extension”

Refinement consistency can adapt from SESE block checking in programming language verification

Extension consistency By imposing refinement consistency checking and consistent synchronization rules

WISE’11, 12-14 October 2011, Sydney, Australia Sira Yongchareon, Chengfei Liu, and Xiaohui Zhao 30

ACC Model : Validating changes Synchronization consistency checking

Locally-bound lifecycle When an extended artifact totally syncs within the refined SESE L-fragment

Transitivity Extended artifact syncs within another locally-bound extended artifact

WISE’11, 12-14 October 2011, Sydney, Australia Sira Yongchareon, Chengfei Liu, and Xiaohui Zhao 31

ACC Model : Conclusion Artifact-centric Collaboration model

Private/Public view construction Model verification

Changes and validation Valid change Modified private view consistent to its original private

view and conforms to the public ACC Consistent “refinement” and “extension”

What’s this all about? Organization is flexible and free to change and implement its own

part without revealing its private/sensitive information to other organization while still preserving global correctness of the collaboration

WISE’11, 12-14 October 2011, Sydney, Australia Sira Yongchareon, Chengfei Liu, and Xiaohui Zhao 32

Open Challenges Realization approach?

On traditional “task-based” workflow system Need model-model transformation, e.g., ArtiFlow BPEL (Narendra,

N.C., SCC 2009 and Liu, G., ICSOC 2009) Pose loss of information and degrade flexibility (of business rules)

Inefficiency in Monitoring/Tracking due to model conversion/mapping

Alternative? Pure artifact-centric workflow systemProcess driven by pure business rule engine (SOA supported)

Artifact-centric model can be directly (fully automated) executed

Efficient-level of flexibility and monitoring ability

WISE’11, 12-14 October 2011, Sydney, Australia Sira Yongchareon, Chengfei Liu, and Xiaohui Zhao 33

Open Challenges Our current developing work “A Framework for Automated

Realization of Artifact-centric Business Processes in SOA” ACP Realization framework

ACP System architecture

To be appeared in the proceeding of DASFAA 2012To be appeared in the proceeding of DASFAA 2012

WISE’11, 12-14 October 2011, Sydney, Australia Sira Yongchareon, Chengfei Liu, and Xiaohui Zhao 34

Thank you