Ontology-based Semantic Annotations for Business
Processes in BPMN2.0
Hui Liu
1,2
and Jean-Pierre Bourey
1,2
1
Univ Lille Nord de France, Lille, F-59000, France
2
Ecole Centrale de Lille, Laboratoire de Modélisation et de Management des Organisations
Cité Scientifique – BP 48 – 59651, Villeneuve d’Ascq, France
Abstract. This paper analyzes the reason of BPMN emergence and points out
that business processes in BPMN2.0 need semantic information to align
Business and IT. In order to supplement semantic information in BPMN2.0,
four methods of ontology-based semantic annotations are proposed and they are
all built on the extension mechanism of BPMN2.0. The advantages and
disadvantages of the four methods are subsequently discussed. This paper also
discusses how semantic annotations benefit the vertical model transformation of
business processes.
1 Introduction
Before the advent of computers, business processes are written in papers and
performed by human beings. After information systems came out in computer science
domain in 1970s [1], business processes were partially implemented by application
logics (software) [2], which improved the management efficiency and productivity of
companies. However, all of business processes were buried in software, and they were
not easy to monitor by managers in companies. So in 1990’s, workflow management
systems (WMS) appeared, and they were later renamed Business Process
Management Systems (BPMS), which can design, implement, execute, manage and
analyze business processes explicitly [3]. Unfortunately in WMS/BPMS, business
processes description languages were derived from the traditional programming
languages and they were difficult for business analysts to learn and use [2]. It means
that there is a wide gap between business domain and IT domain. During the
alignment of business and IT, BPMS and SOA went together to realize business
agility [4] – companies could be more rapidly adapted to business changes from
customers, market or themselves. As web service is de-facto implementation protocol
of SOA, nowadays BPMSs are more and more based on web service-based XML
execution languages [5]. However, these languages such as WS-BPEL[6] are still
oriented to IT engineers, not to business people. In order to address the interoperation
of business processes at human-level [5], BPMN was created and published out in
Version 1.1 by OMG in 2008. In order to model collaborations between companies,
some important concepts such as “conversation” and “choreography” were added into
BPMN2.0 released in January 2011.
Liu H. and Bourey J..
Ontology-based Semantic Annotations for Business Processes in BPMN2.0.
DOI: 10.5220/0003567200240033
In Proceedings of the International Joint Workshop on Information Value Management, Future Trends of Model-Driven Development, Recent Trends in
SOA Based Information Systems and Modelling and Simulation, Verification and Validation (FTMDD-2011), pages 24-33
ISBN: 978-989-8425-60-7
Copyright
c
2011 SCITEPRESS (Science and Technology Publications, Lda.)
BPMN2.0 can provide business people and IT engineers with a common and user-
friendly graphical notation of business processes, but it can’t make them have the
same understanding of contents in business processes. That’s to say BPMN2.0 defines
the graphical notation and expression syntax of business processes, but it lacks
semantic information about contents of business processes. So in order to align
business and IT, semantic information of business processes is necessary. Besides, if
business processes have semantic information, it will help to discover and reuse
processes (or process fragments) [7-9] and it will also improve the automation degree
of BPM [9-11].
Moreover, Model-Driven Architecture (MDA) [12]/Model-Driven Interoperability
(MDI) [13] are attracting more and more attentions in both scientific and industrial
domains to align business and IT, so MDA/MDI and business process management
(BPM) are integrated together, especially in order to research
collaborations/interoperability between enterprises from the viewpoint of MDA/MDI.
[14, 15] use collaborative business processes to model their collaborations at the
computation-independent model (CIM) level and BPMN is the preferable model
language. [14, 15] all point out that the modeling of collaborative business processes
must be supported by ontologies. So this paper will provide four ontology-based
methods to annotate semantic information into BPMN2.0-based business processes.
The rest of the paper is structured as follows. Section 2 presents the related work in
the research domain of semantic business processes. Section 3 elaborates the four
methods of ontology-based semantic annotations and compares them. Section 4 shows
the benefits of semantic annotations to the vertical model transformation of business
processes. Section 5 concludes the whole paper.
2 Related Work
In order to research semantic information of business processes, two aspects should
be considered: which kind of information should be ontologized and how to represent
the information. For the first aspect [16, 17], which are based on European SUPER
project (Semantics Utilised for Process management within and between EnterPrise)
1
,
have proposed three kinds of ontologies: process ontology, organisational ontology
and domain ontology. Process ontology describes the structure of business processes
whereas organisation ontology describes the artifacts involved in business processes
(such as actors, resources etc), and domain ontology provides information specific to
a company. [16] also shows that the three kinds of ontologies have different contents
in different phases of BPM lifecycle.
For the second aspect, we have two choices: first, represent whole business
processes as ontologies including the structure and the content of business processes;
second, add semantic annotation for contents of business processes. [18] has proposed
a General Process Ontology and an application domain ontology to ontologize the
structure and content of business processes. In order to do the experiments of
semantic process retrieval, [19] has transformed approximately 5000 business
1
http://www.ip-super.org/
25
processes into OWL described by the concepts of MIT Process Handbook
2
. [20] has
proposed semantic BPMN which constructs BPMN concepts in OWL and uses these
definitions to instantiate BPMN processes. [20] has also proposed semantic BPEL
(sBPEL), semantic Event Process Chain (sEPC) to describe business processes and it
wants to transform business processes based on these ontologies into that based on
BPMO and at last it hopes BPMO can bridge sBPMN, sEPC and sBPEL together. To
achieve the goal, [21] has done the ontology-based translation of business process
models from Business Process Modeling Ontology (BPMO) to sBPEL and from
sBPEL to BPMO. This paper will discuss the second choice, like SAWSDL
3
realized
by WSMO Studio
4
.
3 Semantic Annotations for Business Processes in BPMN
In this paper, semantic annotations for business processes are based on ontologies,
i.e., the annotations will refer to concepts, properties or instances in ontologies
(shown in Fig. 1). However, the construction and distribution of ontologies are
beyond the scope of this paper, so this paper will just focus on how to associate
ontology with BPMN2.0-based business processes. Before that, we provide a concrete
Fig. 1. Ontology-based Semantic Annotations for Business Processes.
example that indicates why a semantic annotation is necessary to business processes:
in a company, for the preparation of an anniversary celebration, there are lots of tasks
to do, one of which is to buy 5 beautiful notebooks as awards. To the organisers of the
preparation activity, “notebook” maybe means “book with blank pages for recording
notes or memoranda”
5
. However, if the preparation process of the celebration is
supported by information systems and the task, “buy 5 notebooks”, is implemented by
IT engineers as “find a notebook provider on the Internet and send electronic
request”, to IT engineers, “notebook” may be “notebook computer (a small compact
portable computer)”
5
. That’s to say “notebook” has ambiguity in the “preparation”
process. However, this is just one case for semantic heterogeneity [22, 23]. So the
contents in business processes must be annotated with semantic information for
disambiguation between different people. The following will explain how to realize
the semantic annotation for BPMN2.0-based business processes.
BPMN2.0 metamodel provides an extension mechanism. This allows business
process metamodel to be extended but to be still BPMN-compliant. In BPMN2.0
metamodel, such extensibility is implied in the definitions of “baseElement” (Page 64
2
http://ccs.mit.edu/ph/
3
http://www.w3.org/TR/sawsdl/
4
http://www.wsmostudio.org
5
http://wordnetweb.princeton.edu/perl/webwn
26
of [5]), “rootElement” (Page 65 of [5]), “documentation” (Page 64 of [5]), and
“extension” (Page 60 of [5]. This paper proposes the four ontology-based methods of
semantic annotations. Before the elaboration of the four methods, the outline of
BPMN2.0 files is provided in Fig. 2 (a). BPMN2.0 files are based on XML, and their
root element is “definitions” (Page 54 of [5]), and normally it contains two scopes:
one for the structure of collaborations/choreographies/processes and the other for the
visualization of all graphical notations in business collaborations/choreographies/
processes.
(a)
<definitions …>
</definitions>
Scope of semantics
Scope of visualization
Scope of structure
(b)
(c)
(d)
Fig. 2. Structures of BPMN2.0 Files.
3.1 “rootElement”-based Semantic Annotation
According to BPMN2.0 metamodel, “rootElement” is a child element of “definitions”
and it can be replaced by its subclasses, so we can define a subclass of rootElement’s
data type and create a corresponding element to replace “rootElement”. The schema
definition for the scope of semantics is as follows.
Schema definition for semantic annotations of BPMN2.0 (not complete)
<xs:complexType name="tSemanticAnnotation">
<xs:complexContent>
<xs:extension base="bpmn20:tRootElement">
<xs:sequence>
<xs:element name="detail" type="tSemanticDetail"
minOccurs="0" maxOccurs="1"/></xs:sequence>
<xs:attribute name="bpmnElement" type="xs:QName"/>
<xs:attribute name="ontologyRef" type="xs:anyURI"/>
<xs:attribute name="level" type="tMDALevel"/>
</xs:extension></xs:complexContent>
</xs:complexType>
<xs:complexType name="tSemanticAnnotationList">
<xs:complexContent>
<xs:extension base="bpmn20:tRootElement">
<xs:sequence>
<xs:element name="semanticAnnotation"
type="tSemanticAnnotation" minOccurs="0"
maxOccurs="unbounded"/>
</xs:sequence></xs:extension></xs:complexContent>
</xs:complexType>
<xs:element name="semanticAnnotationList"
type="tSemanticAnnotationList"
substitutionGroup="bpmn20:rootElement"/>
27
In the above code, the type “tSemanticAnnotation” defines which attributes
should be included in the semantic annotation for an element in BPMN2.0-based
business processes. Its attribute “bpmnElement” points to a corresponding element in
the scope of structure. The attribute “ontologyRef” points to a concept defined in an
ontology and the concept explains what the above “bpmnElement” means. The
attribute “level” means an MDA level at which the semantic annotation is. The sub-
element “detail” contains the detailed semantic information of the annotated element
and it can appear at most one time in a semantic annotation, for example, for a certain
task in a business process, there is not any corresponding concept/instance in the
dependent ontology, then the task can be described by its actors, action, resources and
other conditions which may have corresponding concepts/instances. Besides, the list
semanticAnnotationList” contains all required semantic annotations for elements in
business processes.
After applying the above schema into a business process in BPMN2.0, the
BPMN2.0 files will be like Fig. 2 (b). The following gives an example of the scope of
semantics (the namespace in Italic is the namespace of the dependent ontology).
Example of “rootElement”-based semantic annotation
<bpmnsa:semanticAnnotationList id="sid-1">
<bpmnsa:semanticAnnotation id="sid-2_s"
bpmnElement="sid-2"
ontologyRef="{namespace}/logisticOnto.owl#TrainTicket"
level="CIM"/>
</bpmnsa:semanticAnnotationList>
However, this method requires that the new schema and the original BPMN2.0
schema (metamodel) share the same “targetNamespace”, and BPMN2.0 schema must
include the new schema. That’s to say the original BPMN2.0 schema will be
modified, and this is the drawback of the method.
3.2 “extension”-based Semantic Annotation
According to BPMN2.0 metamodel, “extension” is a sub-element of “definitions”,
and it can be extended. So this method is to add semantic annotations into the
“extension” element. The definition of semantic annotations is the same as that in the
first method. After applying this method into a business process, the BPMN2.0 files
will be like Fig. 2 (c). The following gives an example of the scope of semantics. In
this method, the scope of semantics is included in the scope of “extension”, not
directly stored as the sibling scope of business processes’ structures like
“rootElement”-based method, so the representation style of semantic annotations in
this method is less clear than that in “rootElement”-based method.
28
Example of “extension”-based semantic annotation
<extension definition="semanticAnnotation">
<documentation>
<bpmnsa:semanticAnnotationList id="sidl-1">
<bpmnsa:semanticAnnotation id="sid-2_s"
bpmnElement="sid-2"
ontologyRef=
"{namespace}/logisticOnto.owl#TrainTicket"/>
</bpmnsa:semanticAnnotationList>
</documentation></extension>
3.3 Attribute/Element-based Semantic Annotation
In BPMN2.0 metamodel, the type of “baseElement” makes it possible to add new
attributes or new elements into it, and fortunately collaboration, choreography,
process, task, artefact, event, message, gateway, participant and expression are
extended based on the type of “baseElement”, so all of the above concepts can add a
new attribute to point to a concept defined in an ontology. The attribute can be
defined as follows.
Attribute definition for semantic annotation
<xs:attribute name="ontologyRef" type="xs:anyURI" />
So after applying such annotation method, the extended business process is
obtained and the following shows one fragment.
Example of attribute-based semantic annotation
<dataObject id="sid-2" isCollection="false"
name="ticket"
bpmnsa:ontologyRef=
"{namespace}/logisticOnto.owl#TrainTicket"/>
In this method, all semantic annotations are scattered in BPMN2.0 files, not like
the above two methods where all semantic annotations are collected in one scope. The
structure of BPMN2.0 files is like Fig. 2 (d). This method is similar to SAWSDL.
3.4 “textAnnotation”-based Semantic Annotation
As “textAnnotation” is extended from the type of “baseElement”, so it has
extensibility inherently. And “textAnnotation” can be associated with activities,
events, gateways, message flows, sequence flows and other objects whose type is
derived from the type of “baseElement”. So “textAnnotation” can be used as a
method of semantic annotations. However, “textAnnotation” is associated with an
annotated element by an association, not like the above three methods which associate
semantic annotations and annotated elements by ID mappings (“bpmnElement” in
Section 3.1). In a business process, the usage of “textAnnotation”-based semantic
annotation is as follows and the structure of BPMN2.0 files will be like Fig. 2 (d).
29
Example of “textAnnotation”-based semantic annotation
<textAnnotation id="sid-3" textFormat="text/plain">
<text>
<bpmnsa:semanticAnnotation id="sid-2_s"
ontologyRef=
"{namespace}/logisticOnto.owl#TrainTicket"/>
</text></textAnnotation>
In terms of the above elaboration of four methods, the first two methods collect all
semantic annotations together in the scope of semantics, instead the second two
methods merge semantic annotations within the scope of business processes’
structures. Table 1 compares the four methods in detail.
Table 1. Comparison between four semantic annotation methods of business processes.
Semantic Annotation advantages disadvantages
“rootElement”-based Keep all semantic
annotations together;
Modify the metamodel of
BPMN2.0;
“extension”-based Keep all semantic
annotations together;
Less clear than “rootElement”-
based SA
attribute/element-based Semantic annotations are
attached directly to
designated BPMN elements;
All semantic annotations are
scattered in the structure scope
of BPMN files;
“textAnnotation”-based Semantic annotations are
attached to designated;
BPMN elements
Not directly mapped;
“textAnnotation” appears
everywhere in BPMN
graphical diagrams;
The above four ontology-based semantic annotation methods can be adopted by
BPMN2.0 Tools such as BizAgi Xpress
6
, Oracle BPM Suite
7
, Bonita Open Solution
8
etc. According to Table 1, the second method is preferable. If BPMN2.0 tools want to
add semantic annotations into business processes, they must provide IT engineers
with a graphical user interface (GUI) which could show all concepts/instances in
dependent ontologies and which should also easily associate them with graphical
elements in business processes. Of course, these tools should also provide a GUI for
IT engineers to create detailed semantic annotations -- “detail” in Section 3.1, which
can help generate new concepts/instances in dependent ontologies.
4 Semantic Annotations and Model Transformation
Besides facilitating process (or process fragment) discovery and reuse, semantic
information in business processes can also help model transformation in MDA
research domain. In [15], a process-based method for enterprise interoperability has
been proposed and it is integrated with MDA. At the CIM level, this method uses
collaborative business processes to describe collaboration requirements between
6
http://www.bizagi.com/index.php?option=com_content&view=article&id=19&Itemid=100
7
http://www.oracle.com/us/corporate/press/079865
8
http://www.bonitasoft.com/
30
enterprises and after several model (business process) transformations, it is expected
to generate several executable business processes. Each business process
transformation will need semantic information retrieved from ontologies and add new
information into generated business processes. Semantic Annotations for business
processes can be a suitable method to support such business process transformation.
Fig.3 shows a general model transformation in the method of [15] and the
transformation takes advantage of semantic annotations. In Fig. 3, Business Process i
has the existing semantic annotations which point to ontology, especially point to
Ontology i, and the newly generated Business Process j contains new semantic
annotations besides the originals. The new semantic annotations also point to
ontology, especially points to Ontology j. During the transformation from Business
Process i to j (from MDA high level to MDA low level), the mapping between
Ontology i and j will be needed. With the help of the mapping, the transformation will
find the concepts/instances in Ontology j corresponding to concepts/instances in
existing semantic annotations of Business Process i. The new semantics will be added
into Business Process j.
Business Process i
Scope of Semantics
Existing
Semantics
Business Process j
Scope of Semantics
Existing
Semantics
New Semantics
Ontology
Ontology i
Ontology j
Model transformation
mapping
Fig. 3. Semantic Annotations in Business Process Transformation.
From the above narration, semantic annotations of business processes are very
useful for vertical model transformation (from MDA high level to low level).
5 Conclusions
Business processes need semantic information during the alignment between business
and IT. In order to supplement semantic information in BPMN2.0-based business
processes, this paper has presented four methods of ontology-based semantic
annotations and these methods are all built on the existent extensibility mechanism of
BPMN2.0. After the comparison of the four methods, the “extension”-based semantic
31
annotation method will be preferable to the other three methods. This paper has also
shown that semantic annotations are helpful to the vertical transformation of business
processes (a business process is regarded as a model in MDA).
Apart from bringing benefits to BPMN2.0-based business processes, semantic
annotations are also beneficial to ontologies. This paper has indicated that the detailed
semantic annotations will help to generate new concepts/instances to enhance
contents of ontologies. Furthermore, semantic annotations imply the reversible
associations between business processes and ontologies, hence some
concepts/instances in ontologies have corresponding structural elements in business
processes and they can find their preconditions/post-conditions through business
processes. In fact, business processes can be regarded as contexts for some
concepts/instances in ontologies. So, BPMN2.0-based business processes are one kind
of structural annotations for ontologies.
Acknowledgements
This work has been partially funded by the ISTA3 project. This project has been
labeled by the Aerospace Valley Pole in Aquitaine/Midi-Pyrénées in France.
References
1. C. Avgerou, "Information systems: what sort of science is it?," Omega, vol. 28, pp. 567-
579, 2000.
2. D. E. Jenz. Ontology-based business process management-the vision statement. 2003.
Available: http://www.bpiresearch.com/Resources/WP_BPMVision.pdf
3. W. M. P. van der Aalst, A. H. M. ter Hofstede, and M. Weske, "Business Process
Management: A Survey," in Proceedings of the International Conference of Business
Process Management, Eindhoven, The Netherlands, 2003, pp. 1-12.
4. C. Ling and L. Xin, "Achieving Business Agility by Integrating SOA and BPM
Technology," in 2009 International Forum on Information Technology and Applications,
Chengdu, China, 2009, pp. 334-337.
5. OMG, "Business Process Model and Notation (BPMN) Version 2.0," ed: Object
Management Group, 2011.
6. A. Alve and A. Arkin, "Web Services Business Process Execution Language Version 2.0,"
ed: OASIS, 2007.
7. K. Belhajjame and M. Brambilla, "Ontology-based Description and Discovery of Business
Processes," in 10th Workshop on Business Process Modeling, Development, and Support
(BPMDS) at CAiSE 2009, Amsterdam, 2009, pp. 85-98.
8. M. Dimitrov, A. Simov, S. Stein, and M. Konstantinov, "A BPMO Based Semantic
Business Process Modelling Environment," in ESWC-SBPM, Innsbruck, Austria, 2007.
9. W. Abramowicz, K. Haniewicz, M. Kaczmarek, and D. Zyskowski, "Semantic Modelling
of Collaborative Business Processes," presented at the Proceedings of the 2009
International Conference on Information, Process, and Knowledge Management, 2009.
10. A. Awad, A. Polyvyanyy, and M. Weske, "Semantic Querying of Business Process
Models," in Enterprise Distributed Object Computing Conference, 2008. EDOC '08. 12th
International IEEE, 2008, pp. 85-94.
32
11. M. Hepp, F. Leymann, J. Domingue, A. Wahler, and D. Fensel, "Semantic Business
Process Management: A Vision Towards Using Semantic Web Services for Business
Process Management," in Proceedings of the IEEE ICEBE, 2005, pp. 535-540.
12. J. Miller and J. Mukerji, "MDA Guide Version 1.0.1," ed: Object Management Group,
2003.
13. J.-P. Bourey, R. Grangel, G. Doumeingts, and B. Arne-J., "Deliverable DTG2.3 Report on
Model-Driven Interoperability," 15 May 2007.
14. J. Touzi, "Aide à conception de système d'information Collaboratif support de
l'interopérabilité des enterprises," Doctoral, Centre de Génie Industriel, Ecole des Mines
d'Albi Carmaux, 2007.
15. H. Liu, A.-F. Cutting-Decelle, and J.-P. Bourey, "Use of Ontology for Solving
Interoperability Problems between Enterprises," in Collaborative Networks for a
Sustainable World--11th IFIP WG 5.5 Working Conference on Virtual Enterprises, PRO-
VE 2010, St. Etienne, France, October 11-13, 2010. Proceedings. vol. 336, L. Camarinha-
Matos, X. Boucher, and H. Afsarmanesh, Eds., ed: Springer Boston, 2010, pp. 730-737.
16. A. Filipowska, M. Hepp, M. Kaczmarek, and I. Markovic, "Organisational Ontology
Framework for Semantic Business Process Management," in Business Information Systems.
vol. 21, W. Abramowicz, Ed., ed: Springer Berlin Heidelberg, 2009, pp. 1-12.
17. A. Filipowska, M. Kaczmarek, M. Kowalkiewicz, I. Markovic, and X. Zhou,
"Organizational ontologies to support semantic business process management," presented at
the Proceedings of the 4th International Workshop on Semantic Business Process
Management, Heraklion, Greece, 2009.
18. Y. Lin and H. Ding, "Ontology-based Semantic Annotation for Semantic Interoperability of
Process Models," in Proceedings of the International Conference on Computational
Intelligence for Modelling, Control and Automation and International Conference on
Intelligent Agents, Web Technologies and Internet Commerce Vol-1 (CIMCA-IAWTIC'06)
2005, pp. 162-167.
19. C. Kiefer, A. Bernstein, H. J. Lee, M. Klein, and M. Stocker, "Semantic Process Retrieval
with iSPARQL," presented at the Proceedings of the 4th European conference on The
Semantic Web: Research and Applications, Innsbruck, Austria, 2007.
20. SUPER-Project, "D.1.1. Business Process Ontology Framework," SUPER
Deliverable,April 2007.
21. B. Norton, L. Cabral, and J. Nitzsche, "Ontology-Based Translation of Business Process
Models," presented at the Proceedings of the 2009 Fourth International Conference on
Internet and Web Applications and Services, 2009.
22. Z. Xu and Y. C. Lee, "Semantic Heterogeneity Of Geodata " in ISPRS Commission IV, WG
IV/2, Ottawa, Canada, 2002.
23. H. Wang and J. N. K. Liu, "Analysis of Semantic Heterogeneity Using a New Ontological
Structure Based on Description Logics," in Fuzzy Systems and Knowledge Discovery, 2009.
FSKD '09. Sixth International Conference on, 2009, pp. 216-221.
33