Slide 1Slide 2Slide 3Slide 4Slide 5Slide 6Slide 7Slide 8Slide 9Slide 10Slide 11Slide 12Slide 13Slide 14Slide 15Slide 16Slide 17Slide 18Slide 19Slide 20Slide 21Slide 22Slide 23Slide 24Slide 25Semantic WebA Very Brief Overview…with terminology, figures, definitions, examples, charts, and issues1. What is the Semantic Web?2. Why the Semantic Web?3. Semantic Web Stack4. Semantic Web Layers5. Ontologies6. Example7. Graph Theory8. Solved Problems9. Unsolved ProblemsSemantic WebCooperative Information Systems:1. support smooth interaction with a large variety of independent multi-vendor data sources and legacy applications2. run on heterogeneous platforms and distributed information networks3. support metadata to describe the contents of data sources and facilitate their integration4. support community-oriented interaction patterns such as navigation, query, and retrievalWhat is the Semantic WebCooperative Information Systems (cont):5. support personalized notification, annotation, and profiling mechanisms6. support interactions via intelligent interface with application software7. support dynamic integration into customized and highly connected cooperative environments8. ensure security, privacy, and accuracy of contentsWhat is the Semantic WebSyntactic: relating to structureSemantic: relating to meaningThe Semantic Web allows information to be processed automatically by tools as well as manually and can infer potential relationships among pieces of data. It extends principles of the World Wide Web from documents to data through the development of a common framework that allows data to be shared and reused across application, enterprise, and community boundaries. Why the Semantic WebThe Semantic Web solves problems today that were previously unsolvable:•Facilitates interchange between entities with ever-changing requirements without breaking systems•Provides the ability to share or annotate search results/data•Provides capability to analyze items that are potentially relatedWhy the Semantic WebMust serve a diverse mix of demands characterized by content, community, and commerceOn the web (open availability, a.k.a. Linked Open Data):•data AND semantics of data must be available (Why?)•for human, semantics are achieved via a presentation format•for application programs, semantics are achieved via a formal, machine-processable formThe problem:•the meaning of traditional Web content is not machine-accessibleWhy the Semantic WebGoogleFacebookBestBuySearsK-MartWalmartGoodRelations and Schema.org ontologies yield rich search in web searchesLeveraged by:GoogleYahoo!Etc.Semantic tagging allows engines to improve summaryWhy the Semantic WebWho is Using It?Terminology (or Alphabet Soup?)•Specification Oriented Approach •EJB3, JAAS, SSL, W3C Workflow XPDL 2.0•Namespaces: vCard, FOAF, Dublin CoreSimplified Technology Stack•XML•RDF•RDFS•OWL, OWL 2Semantic Web StackLayers(Onion or Parfait?)Semantic Web LayersSemantic Web OntologiesOntology === Abstract Domain Model === SchemaOntology:•the nature of existence•an explicit and formal specification of a conceptualizationSemantic Web Ontologies•Provides for interchangeable format systems to exchange data removing the need for rewrites when information changes•Technology utilizes flexible storage—the storage schema doesn’t require change as problem complexity increases•Next generation of visualization through browsers•Ability to add analytical data through reasoningSemantic Web ExampleFord Taurus HierarchySemantic Web ExampleExpanding the Ford Motor Company ontology will lead to a more formalized data structure and with implied relationships between different pieces of data.For instance Ford produces more than one type of vehicle, and they also make parts for the vehicles they manufacture.Look at what happens when the F-150 Truck, Expedition Sport Utility Vehicle, and some vehicle parts—like a chassis and engine for each—are added.XML DiagramSemantic Web ExampleXML DiagramSemantic Web ExampleWhat happens when Ford Motor Company uses an outside parts manufacturer to supply a part for one of the vehicles it manufactures?What happens when Ford produces another vehicle under a different make and model like the Mercury Sable that is virtually identical to the Taurus?What happens when Ford Motor Company purchases Hughes Aerospace and begins producing aircraft and aircraft parts?XML DiagramSemantic Web ExampleXML DiagramSemantic Web ExampleThe next diagram shows how RDF has simplified the data representation by cleaning up the duplication and establishing the relationships between the different data objects.RDF DiagramSemantic Web ExampleRDF DiagramSemantic Web Graph TheoryGraph Theory is a basic concept used in Semantic Web technologyConsider the subgraph: [node1]---(edge1)---[node2]Then, this is also a triple (node1, edge1, node2)In the Semantic Web, all graphs are directed graphs[node1] ------ (edge1) ------►► [node2]..in the form…(subject, predicate, object) ◄ more on this laterConsider a graph…Semantic Web Graph TheoryN1N2N9N8N6N7N5N4N3E1E7E2E6E5E3E4E8E9The directed graph below can be expressed as triples……as follows…N1, E1, N2N1, E2, N3N2, E3, N4N2, E4, N5N4, E5, N6N5, E6, N6N3, E7, N7N7, E8, N8N8, E9, N9Semantic Web Graph TheoryN1N2N9N8N6N7N5N4N3E1E7E2E6E5E3E4E8E9Semantic Web Solved Problems•Vocabulary oriented ontologies•Solved problem space:We can bring back 3,000 entries from 5 terabytes of data in 250 milliseconds.We can materialize URI’s in 20 milliseconds per URI.As a result, we can bring back one page of data to scale.Utilizes non-relational structure either partially or fully resulting in polynomial response times.RDF & RDFS:Semantic Web Unsolved Problems•Large polynomial based reasoning.•Native RDF viewers.•Vocabulary homogenization•Accuracy with unstructured text (entities and relationships)•Ontology enforcement issuesSemantic Web Summary•The Semantic Web is an initiative that aims at improving the current state of the World Wide Web•The key idea is the use of machine-processable Web information•Key technologies include explicit metadata, ontologies, logic and inferencing, and intelligent agents•The development of the Semantic Web proceeds in