=Paper= {{Paper |id=None |storemode=property |title=MDROntology : An Ontology for Managing Ontology Changes Impacts on Business Rules |pdfUrl=https://ceur-ws.org/Vol-890/paper3.pdf |volume=Vol-890 |dblpUrl=https://dblp.org/rec/conf/semweb/ChnitiAC12 }} ==MDROntology : An Ontology for Managing Ontology Changes Impacts on Business Rules== https://ceur-ws.org/Vol-890/paper3.pdf
    MDROntology : An Ontology for Managing
    Ontology Changes Impacts on Business Rules

                 Amina Chniti1,2 , Patrick Albert1 , Jean Charlet2,3
                                  1
                                CAS France, IBM
                    {amina.chniti,albertpa}@fr.ibm.com
    2
      Inserm UMRS 872 q.20, Ingénierie des Connaissances en Santé, Paris, France
                            Jean.Charlet@upmc.fr
                            3
                              AP-HP, Paris, France



        Abstract. In this paper, we focus on the impact of ontology changes
        on rules, or more specifically on business rules authored over ontolo-
        gies. For this we develop the MDR framework (Model-Detect-Repair)
        based on the MDROntology and a set of rules. As rules depend on the
        ontology entities, ontology changes may make them inconsistent. The
        MDR framework analyses an ontology change to detect its impact (e.g.
        inconsistency) on rules and propose solutions, called repair, to repair the
        change impact. The MDROntology includes, among others, a change
        model, ontology changes classification and the impact of such changes
        on rules.
        Keywords: Ontology Change, Business Rule, Change Impact, Rule In-
        consistency


1     Introduction
Integration of ontologies and rules is a research area of interest especially for the
semantic web community. Ontologies changes also take the attention of many
research works, which propose solutions to manage the changes of the ontologies
while maintaining their consistency. In this paper we focus on the integration of
OWL-DL ontologies and business rules and on the impact on ontology changes on
rules authored over ontologies. Business Rules are a description of a business pol-
icy, encoded in a natural controlled language. They define or specify constraints
of some aspect of the business4 and enable automating business decisions. An
example of a business rule is given in the following :
      IF the yearly income of the borrower is less than 20000
      and the amount of the loan is more than 60000
      THEN reject the loan request;

   The purpose of integration ontologies and business rules is to bring the ex-
pressiveness of OWL ontologies to business users by means of business rules
authored in a controlled natural language. In [3] the authors present a proto-
type which enables authoring and executing business rules over OWL ontologies.
4
    http://www.businessrulesgroup.org
This prototype, called OWL plug-in for WODM, is based on the Business Rule
Management System (BRMS) WebSphere Operational Decision Management
(WODM). Due to this new dependency of business rules on ontologies, changes
to this ontologies have an impact on them and may cause inconsistencies.
    To cope with the problem of inconsistencies, caused by ontology changes, we
develop5 a new approach, Model-Detect-Repair (MDR), which supports con-
sistency maintenance of business rules when ontologies evolve. The general idea
of MDR consists of modeling the ontology change, detecting the inconsistencies
that could be caused by it and propose solutions, called repairs, to resolve the
inconsistencies.

2   MDROntology
The MDROntology, represents the different entities that are important to de-
tect the impact of ontology changes on rules. It contains the concepts to model
business ontology changes, business rule inconsistencies and inconsistency re-
pairs. The MDROntology contains more than one hundred concepts, the most
important are:
 – Entity: represents the entities of an ontology (i.e. concept, property, and
   individual);
 – ChangeObject: represents the OWL-DL construct on which the change ope-
   rates. Six categories of OWL-DL constructs are represented based on the
   W3C guide 6 :
     • ClassAxiomConstruct: rdfs:subClassOf, owl:equivalentClass, owl:disjoint-
       With;
     • ClassDescription: owl:oneOf, owl:intersectionOf, owl:unionOf, owl:comp-
       lementOf ;
     • PropertyRestriction:
         ∗ Cardinality restriction: owl:maxCardinality, owl:minCardinality, owl:-
           cardinality;
         ∗ Value restriction: owl:allValuesFrom, owl:hasValue, owl:someValues-
           From.
     • PropertyRelation: owl:equivalentProperty and owl:inverseOf
     • PropertyCharacteristic:owl:FunctionalProperty,owl:InverseFuctional-
       Property, owl:SymmetricProperty,owl:TransitiveProperty;
     • RDFConstruct: rdfs:subPropertyOf, rdfs:subClassOf, rdfs:domain, rdfs:range.
 – Change: represents ontology changes that have impacts on the rules. We
   distinguish between three categories of change
     • OWLConstructChange: consists of changes that impact a construct. We
       define six categories of OWLConstructChangewhich are ClassAxiomCons-
       tructChange, ClassDescriptionChange, PropertyRestrictionChange,
       PropertyRelationChange, PropertyCharacteristicChange and RDF-
       ConstructChange.
5
  This work is partially founded by the European Commission under the project ON-
  TORULE (IST-2009-231875).
6
  http://www.w3.org/TR/owl-ref/
     • StructuralChange: consists of adding or removing entities;
     • RenameOntologyEntity.
 – Rule: represents the business rules authored by business users, which are
   impacted by a change. They have a ConditionPart and an ActionPart and
   they are authored over the ontology entities (represented by the concept
   Entity);
 – Inconsistency: represents the inconsistencies that could impact rules due
   to an ontology change and we focus on 4 types on inconsistency [6]; Contra-
   diction, Domain Violation, Invalid Rule and Rule Never Apply.
 – Repair : represents the repairs that are proposed to resolve an inconsistency.




                      Fig. 1. MDROntology main concepts


   Within the MDROntology a change is defined as follows (see Figure 1):

 – a change has a ChangeObject which is the OWL construct impacted by the
   change (i.e. owl:subclassOf, owl:allValuesFrom, owl:oneOf. . . );
 – a change is applied to a Change entity that can be a concept or a property;
 – a change has a change type: {Add, Remove, Modify};
 – a change has impact on Rule;
 – a change has impact an Inconsistency hat is repaired by a Repair.

    Nevertheless, depending on the change to apply to the ontology, more infor-
mation should be provided to enable detecting its impact on rules. For example,
in case of an enumeration change, the new collection of the enumeration is pro-
vided (see Figure 2), in case of a rename entity change, the new name of an
entity, in case of a range change, the new range of a property. . .
                      Fig. 2. Enumeration change template


3   MDR Framework

The MDR approach is inspired by ONTO-EVOA L [4], which deals with the
consistency maintenance of OWL ontologies while they evolve. In this context




                           Fig. 3. General architecture


we assume that inconsistencies in the ontology have been resolved. Our focus is
on the inconsistencies that emerge in the rule set as a consequence of the change
in the ontology over which the rule set is authored.
    The general idea of the MDR approach is: (1) to model the changes that
the business user wants to apply to an ontology, (2) to detect which changes
produce inconsistencies and (3) to provide solutions to repair them.
    Figure 3 gives an overview of our approach. We distinguish two different lay-
ers : the Business Layer and the MDR layer. The Business layer consists of the
business ontology which is subject to changes and the business rules authored
over this ontology by the business user. These business rules are possibly im-
pacted by the ontology changes. The MDR layer depicts the architecture of
our system. It contains the MDROntology which models our problem domain
(e.g.ontology change, rules inconsistencies and inconsistency repairs). Addition-
ally, it contains two rule sets, the Inconsistency Detection Rules (IDR) and the
Repair Rules (RR). These rules are authored over the MDROntology using the
OWL plug-in for WODM.The IDR detects which inconsistencies in the business
rules are caused by the change, while the RR proposes the appropriate repairs
for any combination of a change and an inconsistency. These repairs can be ei-
ther changes to the business rule set or to the business ontology. The MDR


                                                                                                     Ontology concept
                                                                                                     Ontology property
                                                                                                     Property value
                                    (c) Iconsistency                                                 Property range
       (d) Repair Rule
                                     Detection Rule
            (RR)
                                          (IDR)
          repairedBy                 Inconsistency
                                                                        “Remove”
                                                              “Add”                “Modify”


                                            hasImpact
            Repair
                                                                      changeType




         Rule              hasImpactOn               Change             hasChangeEntity         Entity



         hasRuleName                                      hasChangeObject                 hasLocalName



            String                                            ChangeObject                  String
                          (b) Rule filter
                         (automatically)
                                                                  (a) The user model
                                                                       (manually)




                                            Fig. 4. MDR Process


process to detect the impact of an ontology change on rules is as follow (see
Figure 4); (a) It starts by modeling the required business ontology changes .
This is done by the business user, by creating individuals of the MDROntology.
These change instances refer to entities in the business ontology that are subject
to change. This change model serves as input for the consistency process. (b)
The Rule Filter module is executed to detected rules that are impacted by a
change. This module updates the change model by adding the impacted rules.
(c) The updated model is used to trigger the IDRs, in order to detect the type
of inconsistencies on the impacted business rules. This step updates the change
model with the detected inconsistencies for each impacted business rule. (d) Fi-
nally, this new updated model is used to trigger the RRs in order to find possible
repairs for each inconsistency.


4     Experimentation

The MDR approach is implemented as a WODM plug-in called the Change
Management plug-in. To illustrate our work, we present a business scenario that
stages two agents representing business users who are involved in the process of
consistency maintenance.
   Marc is the business analyst. His mission is to formalize the business knowl-
edge. He has to make sure that the business model is correct, complete and valid.
Alice is the domain expert. She is in charge of authoring the business rules. She
understands quite well their formalization and uses business rules tools to up-
date, create and test them.
   The business ontology we will use in this section is an extract of the use case
used in the ONTORULE project 7 . The use case, provided by Audi, models a
scenario of a car development. One domain constraint that must be verified is



                                                     Method
                                               description : Section



                                                 VirtualMethod



                                                 MicroSlipTest




                           if
                                  the description of the micro slip test is the section
                      R1
                           then
                                      set the strap is conform to the regulation ;




Fig. 5. Example of a portion of the Audi use case ontology and the rule authored over
it.


that the SolutionConcepts are conform to Regulations. The MicroSlipTest
is a Method that is used to test the quality of a seat belt. When a Method is
based on a Section, the required SolutionConcept for the Process that uses
this Method must be conform to a Regulation. For this, we authored the rule
described in Figure 5 using the OWL plug-in for WODM. This rule expresses,
7
    http://ontorule-project.eu/
that the required Strap (which is a SolutionConcept) for the MicroSlipTest
conforms to a Regulation.
    Let us consider an ontology change that consists of removing the subclass
relation between VirtualMethod and MicroSlipTest. In this case, the rule
R1 will be invalid as it tests the property description of MicroSlipTest, an
inherited property that will be lost after the change application.
    The application of the MDR approach will be as described in the following :
1. Change modeling
   Marc requests the change by modeling its structure. An instantiation of the
   change concept corresponding to the subclass change that he wants to apply
   is given in Figure 6.




                       Fig. 6. Subclass Change structure


   When Marc activates the Change Management plug-in, a list of the requested
   changes is shown. Then, when Alice selects the change(s) to apply, the rule
   filter is triggered to detect the impacted rules. The impacted rules are de-
   tected based on the change entity and the change object. For example, in our
   case the impacted rules are the one using the change entity with an inherited
   property.

2. Inconsistency detection
   Depending on the modeled change, the IDRs are executed. Each change has
   to satisfy constraint(s). For the subclass change, the constraint to verify is
    that, in the rule set, there is no rule using the change entity with a property
    of its super class. If this constraint is not satisfied an inconsistency of type
    Invalid Rule will be detected by the following rule.
    IF change.objectChange = subclassConstruct
    && change.type = "Remove"
    && change.hasImpactOn(a_rule)
    && a_rule.hasRuleEntity(changeEntity)
    && changeEntity.hasRuleProperty(prop)
    && super_concept in changeEntity.superClass
    && super_concept.hasProperty(prop)
    THEN
    change.add_inconsistency(invalid_rule);
3. Inconsistency repair
   Depending on the change to apply and the detected inconsistency one or
   more repair are proposed. For this example, the proposed repairs are :
    – an alternative ontology change; a proposition of additional ontology
       change that will enable to avoid the inconsistency;
       In this case, one of the proposed repairs is to add the missing property (ı.e
       description) to the concept MicroSlipTest. This repair is proposed
       by the following RR.
        IF invalid_rule in change.impact
        && change.changeObject = subclassConstruct
        then
           addMissingProperty();
     – common repairs, which consist of removing the rule or the rule part that
       causes this inconsistency. These repairs are proposed independently of
       the requested change and the detected inconsistency.

5   Conclusion
In this paper, we presented the MDR framework built on top of the MDROn-
tology. This approach enables the impact of ontology changes on rules authored
OWL ontologies. This approach analyses the impact of a change, detects the
inconsistencies that could be caused by its application and proposes repairs to
resolve these inconsistencies. Nevertheless, in the current state of the work, the
IDRs detect only three types of inconsistencies which are the Invalid Rule, Do-
main Violation and Rule Never Apply caused by enumeration change or subclass
changes.
    The IDRs defines the constraints that each change should verify. The de-
velopment of this kind of rules is not an easy task as it is necessary to cover
the changes that impact an ontology and to define manually the constraint that
each change should verify. It would be rewarding to develop a module enabling
to automatically generate these rules depending on the change to apply in a way
to detect more inconsistencies that could impact business rules.
    Another important point to improve is the change modeling step. It would be
interesting to develop a module that detects automatically an ontology change
and models its structure, which will avoid the change modeling step.
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