Semantic MediaWiki (SMW) is a popular semantic wiki engine that enables collective knowledge modeling within the expressivity of a small subset of OWL. However, SMW is limited in offering native support for modeling rules. In this paper, we show that by using templates and semantic queries provided by SMW, it is possible to model several types of rules within SMW, e.g., OWL entailment rules and logic programs. Such modeling practice enables us to perform some broadly useful inference tasks on SMW, e.g., integrity constraint checking

Bao, Jie

Braines, Dave

Ding, Li

Jones, Gareth

Smart, Paul R

English

Abstract—Semantic MediaWiki (SMW) is a popular semantic wiki engine that enables collective knowledge modeling within the expressivity of a small subset of OWL. However, SMW is limited in offering native support for modeling rules. In this paper, we show that by using templates and semantic queries provided by SMW, it is possible to model several types of rules within SMW, e.g., OWL entailment rules and logic programs. Such modeling practice enables us to perform some broadly useful inference tasks on SMW, e.g., integrity constraint checking. I

Jie Bao

Li Ding

Paul R. Smart

Dave Braines

Gareth Jones

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Rule modeling using semantic mediawiki

Southampton (e-Prints Soton)

Rule Modeling Using Semantic MediaWikiJie Bao, Li DingDepartment of Computer Science,Rensselaer Polytechnic Institute,Troy, NY 12180, USA.baojie@cs.rpi.edudingl@cs.rpi.eduPaul R. SmartSchool of Electronics andComputer Science,University of Southampton,Southampton, SO17 1BJ, United Kingdom.ps02v@ecs.soton.ac.ukDave Braines, Gareth JonesEmerging Technology Services,IBM United Kingdom Ltd, Hursley Park,Winchester, Hampshire,SO21 2JN, United Kingdom.dave_braines@uk.ibm.comgarethj@uk.ibm.comAbstract—Semantic MediaWiki (SMW) is a popular semanticwiki engine that enables collective knowledge modeling within theexpressivity of a small subset of OWL. However, SMW is limitedin offering native support for modeling rules. In this paper, weshow that by using templates and semantic queries provided bySMW, it is possible to model several types of rules within SMW,e.g., OWL entailment rules and logic programs. Such modelingpractice enables us to perform some broadly useful inferencetasks on SMW, e.g., integrity constraint checking.I. INTRODUCTIONSemantic MediaWiki (SMW)1 is an extension of Medi-aWiki, the wiki engine used by Wikipedia, that allows users toadd simple semantic annotations (such as categories and typedlinks) to wiki contents. SMW is probably the most successfulsemantic wiki engine with wide adoption and an active usercommunity. One of the limitations of SMW, however, is itslack of native support for modeling rules. Thus, it does notoffer the ability to infer new facts from explicitly stated factsin the wiki. This limitation results in the absence of somefeatures that would otherwise be highly useful. For example,SMW does not provide inferences about the domain and rangeof a property.To overcome this limitation, we show that by using severalextensions of SMW it is possible to model several typesof rules. In the current paper, we report the results of ourrule modeling efforts with respect to two rule types: OWLentailment rules and logic programs. We also demonstrate howSMW rule modeling capabilities can be used to support rule-based integrity constraint checking.SMW has been used in ITA to demonstrate its ability inintelligence collection and plan modeling [1]. It may serve asa tool for military personnel (e.g., soldiers) to codify their ﬁrst-line observations and facilitate automated debrieﬁng. However,due to the lack of rule inference support in SMW, the currentefforts in ITA are limited in addressing some critical needs,e.g., modeling complex operational plans. This paper providessome foundations that may help addressing these issues.II. RULE MODELING IN SMWWe now describe a general strategy in modeling rules withinSMW. The modeling of rules in SMW is enabled by several1http://semantic-mediawiki.org. In this paper we study SMW 1.4.components or extensions of MediaWiki and SMW, includingthe following:² “Ask” Query (part of SMW): SMW provides a simplequery language using the “ask” function2. An ask queryretrieves facts from the wiki based on its query conditions,and presents the query result in a user speciﬁed way.² Semantic Template (part of SMW): a semantic template isa “template” wiki page that can take parameters (in the formof fffparaggg), and speciﬁes the layout, content and semanticannotations of its instances (which are also wiki pages).² Parser Function3: this is an extension to MediaWiki thatincludes the support for conditional content generation, usingthe syntax: ff#if: condition j A j B gg. If “condition” is true,“A” will be generated, otherwise “B” will be generated.² Arraymap (part of SMW): this is a loop function.The general strategy we adopted is to model a rule as atemplate. The antecedents of a rule are speciﬁed by a useror by a semantic query; the satisﬁcation of the antecedents istested using a “if” or an “arraymap” (when a loop is necessary)parser function, and the consequent of the rule correspondsto some new semantic annotations. For example, suppose wehave the following wiki script on a page “Template:Uncle”,which speciﬁes “if X is a brother of Y and Y is the father ofZ, then X is an uncle of Z”.{{#arraymap:{{getValue|[[{{PAGENAME}}]]|brother of}}|,|Y|{{#arraymap:{{getValue|[[Y]]|father of}}|,|Z|[[uncle of::Z]] }} }}Where “getValue” is a template such that{{getValue|A|P}} will return list of property P values ofthe wiki page A. It is essentially an “ask” query:{{#ask:[[{{{1}}}]] |?{{{2}}}=|mainlabel=- |format=list |link=none}}.To invoke this rule at a page X, we can simply add thescript {{Uncle}} to X. Thus if X is related to any wiki pageZ via the “brother of” and “father of” property chain, then Xalso has the annotation “[[uncle of::Z]]” (the SMW script thatstates that X has an “uncle of” property value Z).III. CONCRETE RULE MODELING SCENARIOSIn this section we illustrate the modeling of several broadlyuseful types of rules.2A Mediawiki function is an extension to the basic Mediawiki script syntax,in the form of ff#f: ...gg where f is the function name.3http://meta.wikimedia.org/wiki/ParserFunctions.A. Modeling OWL Entailment RulesInference with OWL (Web Ontology Language) may berealized using a set of entailment rules4. In general, OWLentailment rules may generate sound but not necessarily com-plete inference results. While SMW has only limited nativesupport for inference, we show that some of those rulescan be implemented using the aforementioned template-basedapproach. For example, the following wiki script on the page“Template:Domain” deﬁnes the “rdfs:domain” inference rule:{{#if:{{getValue|[[:{{PAGENAME}}]]|{{{1}}} }}|[[Category:{{{2}}}]] }}Thus, if “{{Domain|has author|Document}}” is addedto a wiki page, then whenever the page has a “has au-thor” property value, the page must be an instance of Cat-egory:Document. In practice, it is often useful to use anothertemplate page as a container of all the rules a user wants touse, and have the container template directly or indirectly (viasome template inclusion chain) included on relevant pages. Ingeneral, this approach will render sound, but not necessarilycomplete, inference results. Many other OWL entailment rulescan be deﬁned in a similar manner5.B. Modeling Logic ProgramsLogic Programs (LP) are a widely used family of rules. Alogic program is a set of rules of the form “H :- B1,..., Bn”,where H is the head of the rule, and Bi is a body literal (abody literal may be a positive or a negative atom predicate).In LP, “not” indicates negation as failure. For example, astatement that “every person is by default right-handed, unlessit is known that the person is left-handed” (this is known asa default rule) can be represented as a LP rule:RightHanded(x):-Person(x), not LeftHanded(x).To model this rule in SMW, we use the following wiki script:{{LP Rule|body= 1::Person; 1:not:LeftHanded|head= RightHanded }}Where “LP Rule” is a template name, “1::Person” indi-cates a unary positive body literal and “1:not:LeftHanded”indicates a unary negative body literal. “Template:LP Rule”is designed in such a way that whenever the body literals areall true, the head will be added as an inferred fact (e.g., as[[Category:RightHanded]]). Due to space limitations, the fulldeﬁnition of the LP Rule template is given online6.C. Application: Integrity Constraint CheckingWe now show a speciﬁc application of rule modeling,namely integrity constraint (IC) checking. An IC rule describeswhen and how a dataset is not complete. From the modelingpoint of view, an IC rule can be represented as a special typeof LP rule with an empty head. For example, if we want to4http://www.w3.org/TR/owl2-proﬁles5For OWL entailment rules that rely on constructs not natively supported bySMW, they can be designed with respect to an OWL meta-model extension [1].6http://tw.rpi.edu/dev/cnl/LP Testspecify that “Every person who is not a child should have aSSN number”, we can represent this constraint as a LP rule::- Person(x), not Child(x), not Has_SSN(x,y)Fig. 1. IC Checking ExampleWe alsoimplementIC rules inSMW in a waythat is similarto that seenfor LP rules.This approachsupports anumber of ICdiagnostic capabilities: it automatically evaluates instancesthat violate an IC rule, and it generates a warning on wikipages containing instances that violate an IC rule (e.g., seeFig. 1). A more complete example is available online7.IV. DISCUSSION AND CONCLUSIONIn this paper, we have shown that by combining SMWwith several other MediaWiki extensions, it is possible tosupport the modeling of several types of rules, e.g. OWLentailment rules and logic programs. We have also shownan application of rule modeling to the problem of integrityconstraint checking in SMW.The most closely related work is the rule extension proto-type of SMW from the Vulcan project halAR8. This prototypeallows users to encode F-Logic rules in order to derive inferredknowledge in the wiki, relying on an external rule engine.In contrast, our approach does not require any external ruleengine. Our approach also allows rules to be locally invokedby controlling template inclusion. This may help to deal withissues of scalability in rule execution.Our future work will focus on the encoding of OWL 2 RLentailment rules in SMW. We will also explore a number ofways to support rule authoring using supportive user interfaces.ACKNOWLEDGEMENTThis research was sponsored by the U.S. Army Research Labora-tory and the U.K. Ministry of Defence and was accomplished underAgreement Number W911NF-06-3-0001. The views and conclusionscontained in this document are those of the author(s) and should notbe interpreted as representing the ofﬁcial policies, either expressedor implied, of the U.S. Army Research Laboratory, the U.S. Gov-ernment, the U.K. Ministry of Defence or the U.K. Government.The U.S. and U.K. Governments are authorized to reproduce anddistribute reprints for Government purposes notwithstanding anycopyright notation hereon.REFERENCES[1] Jie Bao, Paul R. Smart, Nigel R. Shadbolt, and Dave Braines. AControlled Natural Language Interface for Semantic Media Wiki Usingthe Rabbit Language. In Workshop on Controlled Natural Language(CNL’09) (In Press), 2009.7http://tw.rpi.edu/dev/cnl/Integrity Constraint8http://ruledemo.ontoprise.com

A Controlled Natural Language Interface for Semantic Media Wiki Using the Rabbit Language.

Rule Modeling Using Semantic MediaWiki

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Rule Modeling Using Semantic MediaWiki

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