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pl:miw:piw08_hekateonto [2008/06/30 11:39] ikaf |
pl:miw:piw08_hekateonto [2008/07/03 00:03] ikaf grammar;] |
* RuleML | * RuleML |
* [[http://oxygen.informatik.tu-cottbus.de/rewerse-i1/?q=ERDF|ERDF]] | * [[http://oxygen.informatik.tu-cottbus.de/rewerse-i1/?q=ERDF|ERDF]] |
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co to jest [[wp>datalog]]... | co to jest [[wp>datalog]]... \\ |
| (język reguł i zapytań dla dedukcyjnych baz danych, składnia podzbiorem Prologu. W przeciwieństwie do Prologu: |
| * nie dopuszcza złożonych termów jako argumentów predykatów |
| * narzuca pewne ograniczenia na użycie negacji i rekurencji |
| * nie dopuszcza "wolnych" zmiennych - zmienna w następniku reguły musi wystąpić w nie zanegowanej klauzuli poprzednika |
| Ponadto w datalogu kolejność klauzul nie ma znaczenia dla wyniku zapytania.) |
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business rules orchestration | business rules orchestration |
A generalized attribute Ai is a function (or partial function) of the form\\ | A generalized attribute Ai is a function (or partial function) of the form\\ |
{{:pl:miw:atrybut-def2.png|:pl:miw:atrybut-def2.png}}\\ | {{:pl:miw:atrybut-def2.png|:pl:miw:atrybut-def2.png}}\\ |
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"RDF is based on the idea that the things being described have properties which have values, and that resources can be described by making statements that specify those properties and values. RDF uses a particular terminology for talking about the various parts of statements." (W3C RDF Primer) | "RDF is based on the idea that the things being described have properties which have values, and that resources can be described by making statements that specify those properties and values. RDF uses a particular terminology for talking about the various parts of statements." (W3C RDF Primer) |
**Attributes are represented in RDF in a form of RDF Triples (subject, predicate, object) where subject denote the resource being described, predicate indicate the name of the attribute and object points to the attribute (predicate) value.** RDF statements (triples) consist of subject, predicate and object which all are identified by URIs. | **Attributes are represented in RDF in a form of RDF Triples (subject, predicate, object) where subject denotes the resource being described, predicate indicates the name of the attribute and object points to the attribute (predicate) value.** RDF statements (triples) consist of subject, predicate and object which all are identified by URIs. |
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^ Part of an RDF triple ^ Can be ^ | ^ Part of an RDF triple ^ Can be ^ |
* URI references, blank node identifiers and variable that appear in the object position are expressed as values of the attributes rdf:resource, rdf:nodeID and rdf:variable respectively: <code xml> <ex:denotationOf f:resource="#Grigoris"/> </code> | * URI references, blank node identifiers and variable that appear in the object position are expressed as values of the attributes rdf:resource, rdf:nodeID and rdf:variable respectively: <code xml> <ex:denotationOf f:resource="#Grigoris"/> </code> |
* literals that appear in the subject position are expressed as the text content of the corresponding subelement | * literals that appear in the subject position are expressed as the text content of the corresponding subelement |
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==== OWL - Web Ontology Language ==== | ==== OWL - Web Ontology Language ==== |
=== Basic information === | === Basic information === |
"The OWL Web Ontologoy Language is a language for defining and instantiating Web ontologies. Ontology is a term borrowed from philosophy that refers to the science of describing the kinds of entities in the world and how they are related. An OWL ontology may include descriptions of classes, properties and their instances. Given such an ontology, the OWL formal semantics specifies how to derive its logical consequences, i.e. facts not literally present in the ontology, but entailed by the semantics. These entailments may be based on a single document or multiple distributed documents that have been combined using defined OWL mechanisms." ([[http://www.w3.org/TR/2004/REC-owl-guide-20040210/#Introduction|OWL Guide]]) | OWL Web Ontologoy Language - a language for defining and instantiating Web ontologies. |
| Ontology is a term borrowed from philosophy that refers to the science of describing the kinds of entities in the world and how they are related. |
| An OWL ontology may include descriptions of classes, properties and their instances. |
| Given such an ontology, the OWL formal semantics specifies how to derive its logical consequences, i.e. facts not literally present in the ontology, but entailed by the semantics. |
| These entailments may be based on a single document or multiple distributed documents that have been combined using defined OWL mechanisms. (from [[http://www.w3.org/TR/2004/REC-owl-guide-20040210/#Introduction|OWL Guide]]) |
| == Three sublanguages of OWL == |
| OWL provides three increasingly expressive sublanguages designed for use by specific communities of implementers and users. |
| * OWL Lite |
| - supports those users primarily needing a classification hierarchy and simple constraints |
| - it should be simpler to provide tool support for OWL Lite than its more expressive relatives |
| - provides a quick migration path for thesauri and other taxonomies |
| - has a lower formal complexity than OWL DL |
| * OWL DL |
| - supports those users who want the maximum expressiveness while retaining computational completeness (all conclusions are guaranteed to be computable) and decidability (all computations will finish in finite time) |
| - includes all OWL language constructs, but they can be used only under certain restrictions |
| - is so named due to its correspondence with [[pl:miw:piw08_hekateonto:description logics]] |
| * OWL Full |
| - is meant for users who want maximum expressiveness and the syntactic freedom of RDF with no computational guarantees |
| - allows an ontology to augment the meaning of the pre-defined (RDF or OWL) vocabulary |
| - it is unlikely that any reasoning software will be able to support complete reasoning for every feature of OWL Full. |
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| Each of these sublanguages is an extension of its simpler predecessor, both in what can be legally expressed and in what can be validly concluded. |
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| === Attributes representation === |
| Ontologies consist of taxonomies which describe hierarchy and relations between classes and of inference rules to operate on these classes. In this section I will concentrate on the first part. |
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| Using OWL one can represent attributes of classes and individuals. \\ |
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| :?: Czy relacje typu: subclassOf, subpropertyOf to tez atrybuty, czy atrybutami są tylko "pola klasy"? :-| \\ \\ |
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| Describing OWL ontologies one can use ''rdf'', ''rdfs'' and ''owl'' vocabulary.\\ \\ |
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| == Representing attributes regarding the taxonomy== |
| __Sample (and incomplete) definition of a class__ |
| <code xml> |
| <owl:Class rdf:ID="Wine"> |
| <rdfs:subClassOf rdf:resource="&food;PotableLiquid"/> |
| <rdfs:label xml:lang="en">wine</rdfs:label> |
| <rdfs:label xml:lang="fr">vin</rdfs:label> |
| ... |
| </owl:Class> |
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| <owl:Class rdf:ID="Pasta"> |
| <rdfs:subClassOf rdf:resource="#EdibleThing" /> |
| ... |
| </owl:Class> |
| </code> |
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| __Sample description of an individual__ |
| <code xml> |
| <owl:Thing rdf:ID="CentralCoastRegion" /> |
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| <owl:Thing rdf:about="#CentralCoastRegion"> |
| <rdf:type rdf:resource="#Region"/> |
| </owl:Thing> |
| </code> |
| rdf:type is an RDF property that ties an individual to a class of which it is a member. |
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| == Representing properties == |
| Properties let us assert general facts about the members of classes and specific facts about individuals. A property is a binary relation. \\ |
| There are two types of properties in OWL: |
| * datatype properties, relations between instances of classes and RDF literals and XML Schema datatypes [[http://www.w3.org/TR/2004/REC-owl-guide-20040210/#term_datatype|Properties and Datatypes]] |
| * object properties, relations between instances of two classes. |
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| Defining property restrictions: |
| * one can specify the domain and range |
| <code xml> |
| <owl:ObjectProperty rdf:ID="madeFromGrape"> |
| <rdfs:domain rdf:resource="#Wine"/> |
| <rdfs:range rdf:resource="#WineGrape"/> |
| </owl:ObjectProperty> |
| </code> |
| (In OWL, a sequence of elements without an explicit operator represents an implicit conjunction. The property madeFromGrape has a domain of Wine and a range of WineGrape. That is, it relates instances of the class Wine to instances of the class WineGrape. Multiple domains mean that the domain of the property is the intersection of the identified classes (and similarly for range).) |
| * The property can be defined to be a specialization (subproperty) of an existing property using ''rdfs:subPropertyOf'' |
| <code xml> |
| <owl:ObjectProperty rdf:ID="hasWineDescriptor"> |
| <rdfs:domain rdf:resource="#Wine" /> |
| <rdfs:range rdf:resource="#WineDescriptor" /> |
| </owl:ObjectProperty> |
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| <owl:ObjectProperty rdf:ID="hasColor"> |
| <rdfs:subPropertyOf rdf:resource="#hasWineDescriptor" /> |
| <rdfs:range rdf:resource="#WineColor" /> |
| ... |
| </owl:ObjectProperty> |
| </code> |
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| * It is possible to specify property characteristics, which provides a powerful mechanism for enhanced reasoning about a property. Properties can be: |
| * transitive |
| * symmetric |
| * functional |
| * inverse |
| * inverse functional |
| See: [[http://www.w3.org/TR/2004/REC-owl-guide-20040210/#PropertyCharacteristics|Property characteristics]] for details. |
| * One can add further restrictions using ''owl:allValuesFrom'', ''owl:someValuesFrom'', ''owl:cardinality'', ''owl:hasValue'' |
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| == Representing equivalence == |
| Using attributes ''equivalentClass'', ''equivalentProperty'', ''sameAs'' one can define equivalence of classes, properties and individuals. |
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====== Sprawozdanie ====== | ====== Sprawozdanie ====== |
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[[http://gigapedia.org/items/51325/logical-foundations-for-rule-based-systems--studies-in-computational-intelligence---studies-in-computational-intelligence-|A.Ligęza - Logical Foundations for Rule-Based Systems]] \\ | [[http://gigapedia.org/items/51325/logical-foundations-for-rule-based-systems--studies-in-computational-intelligence---studies-in-computational-intelligence-|A.Ligęza - Logical Foundations for Rule-Based Systems]] \\ |
http://oxygen.informatik.tu-cottbus.de/IT/Research/ERDF-JAIR-2008.pdf\\ | http://oxygen.informatik.tu-cottbus.de/IT/Research/ERDF-JAIR-2008.pdf\\ |
| http://www.w3.org/TR/2004/REC-owl-guide-20040210/\\ |
| http://www.w3.org/TR/2004/REC-owl-features-20040210/\\ |