Automatic Generation of Ontologies from Business Process Models

Lukas Riehl Figueiredo and Hilda Carvalho de Oliveira

Institute of Geosciences and Exact Sciences, São Paulo State University (Unesp), Rio Claro, Brazil

Keywords: Business Process Model, BPMN, XPDL, Ontology, OWL, SPARQL.

Abstract: Business process models are used in organizational environments for a better understanding of the interactions

between the different sectors and the interdependencies between processes. However, business process

models may present legibility problems and navigation difficulties as they become extensive. The

representation of implicit knowledge is complex, as well as the interdependencies are not always easy to be

understood. The use of ontologies has opened a complementary perspective to provide processes with

machine-accessible semantics. Ontologies contribute to the conceptualization and organization of the

embedded and unstructured information that is present in the business processes and that must be explored.

The ontologies are used to structure the implicit knowledge that is present in the business processes, allowing

the understanding by machine. They also facilitate the sharing and reusing of knowledge by various agents,

human or artificial. In this context, this work presents a systematic process to generate an ontology from a

business process model in BPMN, allowing to query information about the model. For this, the PM2ONTO

tool was developed, aiming to generate the ontology in OWL automatically and to provide predefined queries,

elaborated with SPARQL.

1 INTRODUCTION

Business process models are used by business

professionals for a better understanding of the

interactions between the different sectors that make

up an organizational environment and the

interdependencies between processes. Despite the

importance of business processes, these processes are

not always part of the organization's knowledge base,

being available only in business process modeling

tools (Guido et al., 2016).

On the other hand, the understanding of the

business domain is also essential for professionals in

the area of Information Technology (IT). They are

responsible for software solutions and for automating

the organization's process flows. Software

requirements must be adherent to the business

environment, both in relation to processes performed

in the environment and to the vocabulary and

language of the business domain. However, many

times the gap between the vision/language of business

professionals and the ones of IT is often too great.

Przybylek (2014) already observed that the

Requirements Engineering process is hampered by

the lack of communication due to the use of many

different notations between the business area and IT.

The BPMN notation (Business Process Model

Notation) defines many graphical features for visual

representation of the elements of a business process

model. In addition, BPMN is a standard of the OMG

(Object Management Group) consortium and has

been increasingly used worldwide. On the other hand,

Correia and Abreu (2015) emphasize that the BPMN

specification is a relatively complex document for

process modelers.

Another important aspect is that the BPMN

specification does not provide a standard for

documenting business process models.

Business process models may present legibility

problems and navigational difficulties as they become

extensive. The representation of the implicit

knowledge in its elements is complex, and

interdependencies are not always easy to understand.

Often, the reading of these models is limited to the

understanding of the graphic elements that compose

the models and their relations.

Some approaches of Business Process

Management follow an ontological perspective,

aiming to provide processes with semantics

accessible by machine (GÓMEZ-PÉREZ, 2010).

According to Gábor and Kõ (2016), the ontologies

contribute to the conceptualization and organization

Riehl Figueiredo, L. and Carvalho de Oliveira, H.

Automatic Generation of Ontologies from Business Process Models.

DOI: 10.5220/0006709100810091

In Proceedings of the 20th International Conference on Enterprise Information Systems (ICEIS 2018), pages 81-91

ISBN: 978-989-758-298-1

of the embedded and unstructured information that is

present in the business processes and that must be

explored. Ontologies are used to structure the implicit

knowledge that is present in the business processes,

allowing the understanding of this knowledge by

machine. They also facilitate the sharing and reuse of

knowledge by various agents, whether human or

artificial.

In this direction, this paper aims to propose a

systematic process for the automatic generation of an

ontology from a business process model in BPMN

notation v2.0. The ontology can map explicit and

implicit knowledge in the model, evidencing existed

relations and interdependencies, as well as facilitating

queries by software systems.

The systematic process requires that the business

process model be exported to the language XPDL

(XML Process Definition Language) v2.2.

This language is specified by the organization WfMC

(Workflow Management Coalition) and provides a

XML-structured file containing the process

definitions. It is important to emphasize that the

business process models that will be used to generate

the ontologies must follow some good modeling

practices and present documentation of their

elements.

The expected objective with the application of the

systematic process is that the BPMN graphic

elements and the documentation associated to them

are properly mapped to classes of the generated

ontology, evidencing the relations and

interdependencies among them.

In addition, this paper presents the PM2ONTO

tool (Process Model To Ontology), to generate the

ontology and allow predefined queries about the

ontology. The XPDL files which correspond to the

business process model are used as inputs for the

generation of the ontology in the language OWL

(Web Ontology Language), using the framework

Apache JENA (Apache Software Foundation, 2017).

The queries about ontology are coded with the

language SPARQL. The Protégé system is used for

the analysis and visualization of the generated

ontologies.

To better understand the context of this work,

Section 2 presents some works related to the

generation of ontologies from business process

models. The intention is to show other directions and

the markable differences with the proposal of this

work. Section 3 presents the steps of the systematic

process for automatic ontology generation. In Section

4 an overview of PM2ONTO tool is presented, as

well as the process for mapping the XPDL elements

to the ontology classes. This section also presents

SPARQL language queries defined for the

PM2ONTO tool. Section 5 presents the application of

the systematic process and the PM2ONTO tool on a

real business process model. The final considerations

and the future works are presented in Section 6.

2 RELATED WORK

Some works in the literature also present approaches

for the creation of ontologies from business process

models in BPMN. Among them: Haller et al. (2007),

Missikoff et al. (2010), Fanesi et al. (2015), Ternai et

al. (2016) and Guido et al. (2016). Only Haller et al.

(2007) and Missikoff et al. (2010) also export the

models to the XPDL language, but they use versions

prior to XPDL 2.2. In addition, the BPMN elements

are not mapped individually to the ontology, as in this

work. On the other hand, Guido et al. (2016) define

only basic relations between the elements of BPMN

and interdependencies are not deeply explored.

However, in this work will be defined all the possible

relations to be extracted from the context where each

element is in the model.

Haller et al. (2007) apply ontology concepts to the

XPDL language (version 2.0), in order to add

semantic value in the process definitions. The authors

present a tool that performs the automatic conversion

of process instances to the ontology, called oXPDL.

The BPMN elements are used to define ontology's

properties, such as functional, control, informational,

organizational, and operational aspects.

In another direction, Missikoff et al. (2010)

propose the creation of a framework based on the

BPAL (Business Process Abstract Language)

language, in order to add semantics to business

process schemas through formalisms and rules. This

language is used in conjunction with domain

ontologies using OWL (Web Ontology Language) to

capture the knowledge of business processes,

resulting in an enterprise knowledge base. It is

observed, the construction of the knowledge base

does not use logical formalisms but a direct mapping

from the BPMN elements to an ontology in OWL.

Fanesi et al. (2015) aim to add greater semantic

value to business process models using the definition

of an unified ontology (composed of several layers)

based on the OWL-FA language (an extension of

OWL-DL). The first layer of the ontology is

composed by metamodels, which contain the

ontology classes. The second layer is formed by

instances of concepts that compose the ontology in

the first layer. Instances of this second layer make up

the third one. The intention of the authors is to allow

ICEIS 2018 - 20th International Conference on Enterprise Information Systems

ontology queries on several aspects of a business

process model. The ontology defined by the authors

should classify each class relative to a BPMN

element, as well as its instance, in a layer. This

approach classifies concepts as classes, instances, or

even then as classes and instances at the same time.

However, in this work, all the elements of a model are

defined as classes, favoring their categorization in the

ontology, as well as the definition of relations and

queries.

Guido et al. (2016) define a metamodel for BPMN

notation v2.0 composed of classes and properties in

OWL. This metamodel covers the same BPMN

elements as this work, with the following major

classes: graphical_element (subclasses swimlane,

flow_object, connecting_object, artifact and data),

lane, pool and supporting_element (subclasses

event_detail and participant). Disjunction constraint

classes are defined from object instances and

properties. However, the relations defined for BPMN

elements are limited and are not self-explanatory,

which makes it difficult to understand the

interdependencies existing in business process

models. In this paper, this type of problem has been

mitigated, since it is not limited only to the direct

relations existing in the business process model;

relations encompass all elements belonging to

interdependencies.

Ternai et al. (2016) use the business process

model converted to an XML file using the BOC

ADONIS modeling platform (Boc Group, 2013).

From this XML file, the authors generate a process

ontology of a metamodel with the following classes:

Actor, IT_System, Data_Object, Process_Step e

Decision_Point. The conversion of a business process

model into an ontology is accomplished through a

script in the XSLT language (Extensible Stylesheet

Language for Transformation). However, this script

must follow a predefined structure; otherwise not all

the elements of the model will be mapped to the

ontology. Instead of using scripts, this work uses a

metamodel that can be applied to any XPDL file to

obtain the classes that will compose the ontology

because it conforms to the existing definitions in the

XPDL files.

3 SYSTEMATIC PROCESS FOR

AUTOMATIC GENERATION

OF THE ONTOLOGY

This section presents the systematization of the steps

for the automatic generation of an ontology in OWL

from a business process model in BPMN v2.0. The

objective is that the graphic elements of BPMN and

the documentation associated to these elements be

properly mapped to ontology classes, evidencing the

relations and interdependencies between these

elements.

In this context, Section 3.1 presents some criteria

in order to execute the mapping to the ontology

suceessfully. Section 3.2 presents the process to

automatically generate the ontology that represents a

business process model.

3.1 Criteria to Business Process Models

The elements of BPMN considered in the business

process models for this work are: activities, sub-

process, events, gateways (exclusives, inclusives and

parallels), artifacts (groups and annotations), data

objects, data stores, extended attributes, pools, lanes,

sequence flows and message flows.

The graphic elements of the model must be

associated with textual documentation, according to

the format of the selected BPMN modeling system

(there is no standardized way to structure the

organization of textual information of the BPMN

elements).

In addition, the models must satisfy the following

criteria, based on good modeling practices:

− Every process must have an unique event, start

event and at least one end, with names "Start"

and "End" respectively;

− A process must contain at least one participant;

− The textual documentation of each BPMN

element must contain at least one of its

descriptive properties: name, description or

documentation;

− The name of an activity must use a verb in the

infinitive;

− The type of activities must always be defined;

− An activity must be performed by at least one

actor;

− Activity actions must not be assigned as gateway

names (gateways represent the routing logic after

a decision making);

− Sequence flows of an exclusive gateway must be

named, except in the case that there are only two

flows representing "Yes" or "No". In this case,

only one of the names can be explicit and the

other can be deduced;

Automatic Generation of Ontologies from Business Process Models

− Sequence flows of an inclusive gateway must be

named;

− Activities that are preceded by a parallel gateway

must be connected at the end by another parallel

type gateway;

− Activities that are preceded by an inclusive

gateway must be connected at the end by another

gateway of the inclusive type;

In this work, extended attributes add important

value to the ontology. These attributes are not

available in all BPMN modeling systems, but are very

useful and their use is encouraged. Extended

attributes assist in documenting the business process

model and in the identification of some software

elements for this work. The Fig. 1 shows the

extended attribute to the activity “Validate Invoice”.

(These attributes will be categorized in the ontology

as functional requirements ("FR"), nonfunctional

requirements (NFR) or business rules ("BR"),

according to the Requirements Heuristics defined by

Nogueira and Oliveira (2017).

Figure 1: Example of extended attribute defined for an

activity.

3.2 Ontology’s Generation

The process for the generation of the ontology counts

on three steps, that must be executed sequentially in

this order:

− Step 1: the business process model in BPMN

notation v2.0 must be exported to the XPDL v2.2

language through a system for business process

modeling. Considering that the model has n sub-

processes, this export will generate n + 1 XPDL

files, one for each sub-process and one for the

main process;

− Step 2: the PM2ONTO ("Process Model to

Ontology") tool should be used to generate the

ontotology automatically, using the XPDL files

generated in the previous step as input. The result

will be an ontology defined in the OWL language

that represents the original business process

model. The PM2ONTO tool executes the

following steps in this order, as illustrated in Fig.

2.1. Reading and mapping XPDL elements for

classes defined from a metamodel that

contemplates the elements of BPMN

considered in this work;

2.2. Generation of the concepts of the ontology

and of the relation properties of them from

the classes generated in step 2.1;

2.3. Storage of the ontology content generated in

a database and provision of the ontology

OWL file for download.

Figure 2: Overview of the PM2ONTO tool.

4 PM2ONTO TOOL

The PM2ONTO tool was developed in Java language

v1.8 to be used in the Web browser. In addition to the

generation of ontologies, PM2ONTO allows queries

about the generated ontologies (Fig. 3). Queries are

defined in the SPARQL language and can extract

basic information from the elements as well as their

relations within a business process model.

Figure 3: Functionalities of the PM2ONTO tool.

The Apache Jena freeware framework was used to

generate ontologies and queries. The Hibernate

framework (an implementation of Java Persistence

API) was used for persistence and object-relational

mapping of the database; this allowed the storage of

the generated ontologies in a database. The database

system used was MySQL v. 5.7. Protégé system (v.

ICEIS 2018 - 20th International Conference on Enterprise Information Systems

5.0.0 or higher) can be used for the purpose of

visualizing and validating the generated ontologies.

Section 4.1 presents how is the process for

mapping elements of the XPDL files to the classes of

the generated ontology. On the other hand, Section

4.2 presents the predefined queries in the current

version of the PM2ONTO tool.

4.1 Mapping Metamodel’s Classes to

Ontology’s Classes

A metamodel was defined to enable the mapping of

the BPMN elements to the concepts of the ontology.

Fig. 4 shows part of the metamodel in UML (Unified

Modeling Language) notation, while Table 1 shows

the relations used in the metamodel. In Fig. 4 it can

be observed that all classes, with the exception of the

Actor class, have at least the following basic

attributes: identifier, name, description,

documentation, and type. The Actor class does not

contain the type attribute, but contains the other basic

attributes mentioned.

Figure 4: Part of the metamodel’s classes.

The metamodel is formed by 19 classes divided

into three categories:

− Main classes, which correspond to the following

elements of BPMN: Process, Activity,

SubProcess, Event, Gateway, Actor and Artifact;

− Auxiliary or enumerator classes, that define

the types and other specificities of BPMN

elements: SubProcessType, ActivityType,

GatewayType, EventType, ArtifactType,

GatewayDirection and EventTrigger;

− Relation classes, which define the relation

between two or more BPMN elements:

SuceededBy, UsesInput, ProducesOutput,

ExchangesMessageWith, and ExecutedBy.

Table 1: Relations in the metamodel.

Relation Source element Target

Element

Is suceeded by SubProcess,

Activity, Event,

Gatewa

SubProcess,

Activity, Event,

Gatewa

Is executed by Activity Actor

Exchanges

message with

SubProcess,

Activity, Event,

Gateway, Acto

SubProcess,

Activity, Event,

Gateway, Acto

Uses input Activity Artifact

Produces out

ut Activit

, Event Artifact

It is important to mention that the information

defined in the XPDL file about the relative

positioning (coordinates) of the elements in the

business process model were not considered in this

work.

When XPDL files related to a business process

model are entered as input into the PM2ONTO

system, the elements of each XPDL file are analyzed

for the metamodel application and generation of the

ontology. For this, Table 2 shows how the

correspondences between the XPDL elements and the

classes of the metamodel were made. The other

XPDL elements were not considered for class

mapping in this work.

The elements identified as "Performer" were

mapped to the "Actor" class of the metamodel. The

"DataStore", "DataObject" and "Artifact" elements

have been mapped to the Artifact class of the

Metamodel . The "Activity" elements of each process

flow can define one of the following classes of the

metamodel: Activity, Event or Gateway.

The actors were associated to the activities they

perform through the mapping of the "Performer"

elements when found inside the "Activity" element;

in this case, the relations between the actors and their

activities were mapped for the class of the metamodel

ExecutedBy.

The relations between data objects and/or data stores

with activities or events, defined by the

"DataAssociation” and "DataStoreReference"

associations, have been mapped to the UsesInput and

ProducesOutput classes.

When the Activity, Event and Gateway classes

present extended attribute stores, they must be

mapped to the ExtendedAttribute class. Extended

attributes with name "RN", "RF" or "RNF" were

defined as business rule, functional requirement or

Automatic Generation of Ontologies from Business Process Models

Table 2: Relations among the XPDL elements and classes

of the metamodel.

XPDL element Metamodel´s class

WorkflowProcess Process

Performe

Acto

Activity (with element

Task defined)

Activity

Activity (with element

Event defined

)

Event

Activity (with element

Route defined)

Gateway

Activit

Set SubProcess

DataStore Artifact

DataObject Artifact

Artifact Artifact

Artifact (with

ArtifactType defined as

Annotation)

Annotation

Artifact (with

ArtifactType defined as

Grou

Group

ExtendedAttribute ExtendedAttribute

Transition SuceededB

MessageFlow ExchangesMessageWith

Activity (with element

Performer defined)

ExecutedBy

Data Association UsesInput/ProducesOutput

Data Store Reference UsesInput/ProducesOutput

nonfunctional requirement, respectively. In the

sequence, the "ActivitySet" elements were analyzed

and mapped as sub-processes; for each occurrence of

an "ActivitySet", the previous steps of mapping

BPMN elements to the classes were repeated, to

define all the elements belonging to the sub-

processes.

The transitions (element "Transition") contained

in the XPDL files were mapped to the SuceededBy

class of the metamodel, which is formed by two

attributes: source element and destination element.

Message flows ("MessageFlow" element) have been

mapped to the ExchangesMessageWith class, which

also contains the "source element" and "destination

element" attributes.

The classes of the metamodel define the concepts

and the relations that compose the ontology. The

ontology classes are categorized into levels according

to the BPMN elements to which they refer (Fig. 5).

Each class defined from the metamodel is analyzed

and then included as a new class in the ontology,

being classified according to the defined

categorization.

Figure 5: Categorization of classes for the ontology.

The first level classes are:

− AuxiliaryElements: composed of the following

subclasses: EventTriggers, GatewayDirections

and GatewaysOutputs. The class EventTriggers

defines the possible triggers for the event

triggering. The GatewayDirections class defines

the possible directions of a Gateway (divergent

or convergent). The GatewaysResponses class

defines the possible gateway return types;

− Model: is the class that defines the main

information of the original business process

model;

−

ModelElements: this class includes the classes

of the business processes itselves (Process

subclasses) and their elements (ProcessElements

subclasses); this class of the ontology is

composed by the classes of all the elements of a

model. This class is related to the Model class by

means of the isComposedBy object property,

indicating that a business process model is

characterized by a set of elements.

The ProcessElements class is present on the

second level and contains the subclasses: Activity,

Actor, Artifact, Event, ExtendedAttribute, Gateway,

and SubProcess. It is important to mention that the

Activity, Event, Gateway and SubProcess classes are

categorized according to the type they belong to. The

Gateway class, for example, is categorized as

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Exclusive, Parallel, and Inclusive because only the

exclusive, parallel, and inclusive gateways are

considered in this work.

The following data properties were defined for the

ontology with the objective to describe better the

classes: id, name, description and documentation, as

well as the boolean properties isBusinessRule,

isFunctionalRequirement and

isNonFunctionalRequirement. When these boolean

properties have the value "true", it means that the

class that contains this property is identified as a

business rule, functional requirement or non-

functional requirement.

The ontology classes are related through object

properties. In this work, these properties relate two or

more classes of the ontology and are divided into two

groups:

− Basics: define the direct relations that BPMN

elements can assume (Table 3). They are formed

from the transitions, message flows, and

associations present in XPDL files. Inverse

properties have been defined for some of the

basic object properties, such as isPerformedBy,

whose inverse property is isExecutorOfActivity;

− Advanceds: aim to provide a better

understanding of the interdependencies of the

sub-processes, activities, gateways and events

present in a business process model. Table 4

shows the four advanced properties defined and

which are explained below.

The advanced object property

isActivatedWhenEventIsTriggered is defined for the

BPMN elements that are preceded by events. The

intention is to indicate that these elements are invoked

from the trigger caused by the related event.

The isExecutedWhen [Activity name] OutputIs

object property defines the relation between two

BPMN elements interconnected by a routing of an

exclusive gateway. This relation is intended to make

the connection between the element preceding the

exclusive gateway and the element after that gateway

clearer. The element that succeeds the exclusive

gateway is executed after the routing of the execution

result of the first element. It is important to note that

the "[Activity name]" part of the property identifier

refers to the name of the activity that is executed

before the routing performed by the exclusive

gateway. Thus, the constraint for the application of

this property is the existence of an activity succeeded

by an exclusive gateway, provided that the outputs

resulting from the routing of that gateway are

properly named.

Table 3: Basic object properties defined for the ontology.

Pro

ert

Domain Ran

isComposedBy Model ModelElements

isPartOfProcess SubProcess,

Activity,

Event,

Gateway,

Actor,

Artifact

Process

isPartOfSubProce

Activity,

Event,

Gateway,

Actor,

Artifact

SubProcess

isPartOfGroup SubProcess,

Activity,

Event,

Gateway,

Actor,

Artifact

Group

isSuceededBy SubProcess,

Activity,

Event,

Gatewa

SubProcess,

Activity, Event,

Gateway

isPrecededBy SubProcess,

Activity,

Event,

Gateway

SubProcess,

Activity, Event,

Gateway

isPerformedBy Activity Actor

isExecutorOfActi

vit

Actor Activity

usesInput Activity DataStore,

DataObject

producesOutput Activity,

Event

DataStore,

DataObject

hasExtendedAttri

bute

Activity,

Gateway,

Event

ExtendedAttribute

isAnnotatedBy SubProcess,

Activity,

Event,

Gateway

Annotation

exchangesMessag

eWith

SubProcess,

Activity,

Event,

Gatewa

SubProcess,

Activity, Event,

Gateway

The isExecutedAfterParallelExecutionOf object

property defines the relation between a sub-process,

activity, event, or gateway with the parallel flow that

precedes it, if this occurs. The usage constraint of this

property is related to one of the good practices that

must be applied to the business process models used

in the systematic (see Section 3.1). This restriction

defines that all elements between two parallel

gateways indicate the existence of a parallel flow. All

Automatic Generation of Ontologies from Business Process Models

Table 4: Advanced object properties for the ontology.

Pro

ert

Domain Ran

isActivateWhenEventIsTri

ggered

SubProc

ess,

Activity,

Event,

Gatewa

Event

isExecutedWhen[Name of

the activity before the

gateway]OutputIs

SubProc

ess,

Activity

GatewaysOu

tputs

isExecutedAfterParalelExe

cutionOf

SubProc

ess,

Activity

ParallelFlow

(accepts

more than

one)

isExecutedAfterInclusiveE

xecutionOf

SubProc

ess,

Activity

InclusiveFlo

w (accepts

more than

one

)

parallel flows that must be run before an activity are

included as subclass of the ParallelFlow class and

associated with the

isExecutedAfterParallelExecutionOf property.

The isExecutedAfterInclusiveExecutionOf object

property presents practically the same characteristics

as the isExecutedAfterParallelExecutionOf property.

The only difference is that its usage restriction is

defined by two inclusive gateways. All elements

between two inclusive gateways define an inclusive

flow. All inclusive flows that must be run before an

activity are included as a subclass of the

InclusiveFlow class and associated with the

isExecutedAfterInclusiveExecutionOf property.

4.2 Queries about the Generated

Ontology

The PM2ONTO tool provides predefined queries,

structured in the SPARQL language, for users to

obtain information about the ontology. Thus, users do

not need to manually construct a SPARQL query.

Queries are classified into two groups: basic and

advanced.

Basic queries provide information about BPMN

elements, which have been mapped as classes to the

ontology, regardless of the relations defined for those

classes. These queries can use the following data

properties defined for the classes as filters: identifier,

name, description, and documentation. It is also

possible to filter the SubProcess, Activity, Event,

Gateway, and Artifact classes by the "type" attribute.

The expected outputs for basic queries are the main

information about one or more BPMN elements, i.e.

identifier, name, type, description, and

documentation. Queries about any element mapped to

the ontology from the metamodel may contain filters

related to the values of their data properties.

Advanced queries provide information about the

relations and interdependencies between the classes

generated for the BPMN elements. The object

properties defined for the classes of the ontology

enabled the definition of the advanced queries, which

are listed below (PM2ONTO tool version):

1. Activities performed by a specific actor;

2. Predecessor/successor element of a filtered

element in the query;

3. Elements that perform messages exchanges;

4. Elements identified as functional requirements;

5. Elements identified as non-functional

requirements;

6. Elements identified as business rules;

7. Elements that use an artifact as input;

8. Activities that produce an artifact as output (Fig.

6);

9. Activities preceded by an exclusive gateway;

10. Activities preceded by an inclusive gateway;

11. Activities preceded by a parallel gateway.

Figure 6: SPARQL code for query number 8.

5 EXAMPLE OF APPLICATION

OF THE PROPOSED PROCESS

In order to show how to apply the systematized

process presented in Section 3, a business process

model in BPMN v2.0 was selected from the

repository: http://www.bizagi.com/en/community/

process-xchange. There are models with different

levels of complexity in this repository, but all of them

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have been elaborated with the Bizagi modeling

system. This system allows the export of a business

process model to XPDL v2.2 and also allows the use

of extended attributes in the BPMN elements

documentation.

The choice of model took into account that the

conditions presented in Section 3.1 should be

satisfactory. Additionally, the following

characteristics were considered in order to better

demonstrate the process: (a) textual documentation

considered appropriate for all the BPMN elements of

the model; (b) complexity level of the model

considered from medium to high; (c) presence of sub-

processes; (d) presence of extended attributes; (e)

presence of more than one pool.

The "Accounts Payable" business process model

satisfies the requirements of Section 3.1 and the

requirements from (a) to (e), although it required

some adjustments to supplement the documentation.

This model refers to the processes of an Accounting

Department, including submission of documents by

suppliers and subsequent release of the payment after

the validation of them. Fig. 7 shows the Accounts

Payable model with its subprocess.

In order to apply the Step 1, Bizagi modeling

system (v3.1.0.01) was used to export the model to

XPDL v2.2 files. A folder with the XPDL file was

then generated. This file was selected as the input for

the PM2ONTO tool in order to apply the Step 2. The

steps from 2.1 to 2.3 were then executed by the tool,

generating the ontology of the Accounts Payable

Model. Figs. 8 and 9 show excerpts from the ontology

according to the visualization of the Protégé system

(v5.2.0). In these excerpts, interdependencies of

activities and sub-processes with other activities and

sub-processes are evidenced by directing the result

through an exclusive gateway.

The complete ontology presented the following

results:

− 36 classes;

− 129 relations, axioms classes defined from

the object properties;

− 4 business rules;

− 6 Functional Requirements;

− 3 Non Functional Requirements.

It should be noted that the business rules, the

functional requirements and the non-functional

requirements will also assist the Information

Technology (IT) team. These elements can be

obtained in the ontology from the extended attribute

classes, which have the properties of boolean data

(isBusinessRule, isFunctionalRequirement and

isNonFunctionalRequirement) defined with the value

"true". Thus, all business rules, functional

requirements and non-functional requirements can be

queried using the generated ontology.

Figure 7: Accounts Payable Model from Bizagi Repository.

It is important to mention that all the BPMN

elements and the associated documentation were

mapped to the ontology as well as the relations

between the element. The interdependencies were

more explicit in the ontology than in relation to the

business process model. The advanced object

properties, present in the ontology, facilitated the

understanding of some sequences of elements in the

model, such as the property

isExecutedWhen[Activity name]OutputIs (Figs. 8 e

9). This property was defined to improve

understanding of all the business process model parts

that are formed by a decision, indicated by an

exclusive gateway. Moreover, since the

interdependencies were defined as object properties,

the queries about the BPMN elements from their

Automatic Generation of Ontologies from Business Process Models

Figure 8: Relations obtained for a subprocess in the ontology.

Figure 9: Relations obtained for an activity in the ontology.

Figure 10: Result displayed in the Protégé system for the query exemplified as "8".

relations became possible. Thus, the queries

mentioned in Section 4.2 can be made using the

PM2ONTO tool. Table 5 shows the answers to some

query examples for the "Accounts Payable" ontology,

generated from the Accounts Payable Model. That

table shows examples of filters (second column) that

can be passed to the PM2ONTO tool for the 11 types

of available queries (first column). The results shown

in Table 5 are in textual format. However, the

PM2ONTO tool allows results to be displayed in the

OWL language. An example of such a case is shown

in Fig. 10, which illustrates how the query output

exemplified as "8" in Table 5 can be viewed

automatically in the Protégé system.

Table 5: Examples of results for the predefined queries.

Nº Filters Results

1 Actor Name =

'Recepcionist'

Activity Name =

'Receive Invoice'

2 Activity Name =

'Validate Invoice'

Predecessor Name =

'Receive Invoice',

Successor Name =

‘Invoice match with

PO'

3 Activity Name =

'Validate Invoice'

4 Extended Attribute

Name = 'FR'

Extended Attribute

Name = 'FR'

5 Extended Attribute

Name = 'RULE'

Extended Attribute

Name = 'RULE'

6 Extended Attribute

Name = 'NFR'

Extended Attribute

Name = 'NFR'

7 Activity Name =

'Receive Invoice'

Data Object Name =

'Receive Invoice

Form'

8 Activity Name =

'Inform Supplier'

Data Object Name =

'Reject Notification'

9 Gateway Name =

'Invoice match with PO'

Activity Name =

'Validate Invoice'

10 Gateway Name =

'Invoice match with PO'

11 Gateway Name =

'Invoice match with PO'

6 CONCLUSION

The goal of this paper was to present a process to map

elements and knowledge extracted from a business

process model in BPMN to an ontology. The

PM2ONTO tool was introduced to support the

process of automatic generation of the ontology and

provide means for a human user to consult

information about the business process model. The

paper showed how the mapping was designed and

implemented in the PM2ONTO tool. The application

ICEIS 2018 - 20th International Conference on Enterprise Information Systems

of the process for generating the ontology with the

support of the PM2ONTO tool was exemplified

using a real model in this paper.

In order to validate the ontology, criteria based on

the works of Fanesi et al. (2015) and Pizzoleto and

Oliveira (2017) are being elaborated. For this,

organized questions about various aspects of the

business processes model are key tools.

The alternative way of representing a business

process model using an ontology brings several

benefits. Whereas ontologies generated are readable

structures and manipulated by machine, they allow

the application of various techniques and interactions

with digital systems.

The navigation of the model through the ontology

allows better understanding of the activities and

resources, complementing the knowledge about the

business process model. Knowledge can be

embedded in the ontology and shared between

business teams and other interested teams, such as the

IT teams. This helps to approximate the views of

business and IT teams and, consequently, assists the

processes of Requirements Engineering for software

being developed for the organization.

Using ontology integration techniques, business

process models can be integrated, providing broader

queries of interest to the organization. Text mining

techniques can be applied to ontologies, allowing to

improve the system of strategic queries. Information

visualization techniques can also be applied to

business process models using their ontological

representations.

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Automatic Generation of Ontologies from Business Process Models