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JAKUB J. MOSKAL MIECZYSLAW “MITCH” M. KOKAR BRIAN E. ULICNY NOVEMBER 19, 2014 Comprehension of RDF Data Using Situation Theory and Concept Maps

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Outline 2 Lots of RDF data. Querying with SPARQL produces complicated RDF graphs Objective: Generate “simple” Concept Maps Situation Theory (Barwise, Perry, Devlin) STO: Situation Theory Ontology Process outline and processing steps Examples Conclusions

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Abundance of Data 3 Analysts are required to sift through tremendously large amounts of data Keyword-based queries yield poor results Structured data is needed The number of RDF data sets is growing rapidly Even though RDF data is structured, it can be very difficult to analyze Source: http://lod-cloud.net/http://lod-cloud.net/

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Linked Open Data cloud diagram As of 08/30/2014 4 Linking Open Data cloud diagram 2014, by Max Schmachtenberg, Christian Bizer, Anja Jentzsch and Richard Cyganiak. http://lod-cloud.net/

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Example Query Query: What were the circumstances of Richard H. Barter’s death? RDF Data: SPARQL Endpoint: http://dbpedia.org/sparql SPARQL query: PREFIX dbpedia-owl: DESCRIBE ?resource WHERE { ?resource dbpedia-owl:abstract ?abstract. FILTER langMatches(lang(?abstract), "EN" ). FILTER REGEX(str(?abstract), "Richard H. Barter") } LIMIT 10 5

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Query Result: RDF graph 6

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Our Approach 7 Objective: Given a query, transform the input RDF graph to a Concept Map that: Provides answer to the query Contains facts that are relevant to the query (context) Is more abstract than the original RDF graph(easier to comprehend) Approach: Use key aspects of Situation Theory of Barwise and Perry (extended and formalized by Devlin) Map the problem to this theory and implement algorithms for constructing concept maps based on such a framework

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Expected Benefits 8 Increased analyst productivity Easier comprehension Tailored visualization Explanatory facts Improved quality of analyst products Fewer false alarms More detections of relevant events Enriched fact base via inference Augmented with situation types and their instances Integration with other analyst tools Export to standard formats

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Concept Maps 9

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A Bit of Situation Theory 10 - Infon - S “supports” Infon - Situation Type - Abstract Situation - Definitional Query - Inferring situations and their types - “Relevance” – via entailment

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Situation Theory – Relevance Reasoning Relevant entities with respect to a given query Q are those entities that are necessary for proving that a specific set of facts S Q supported by a situation satisfies Q. 11

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Situation Theory – Why? It grounds meaning in the world, rather than in the language (unlike in FrameNets) It allows specifying views of the world (situations) that are globally inconsistent, but locally consistent Situations are first-class citizens – they have their own relations and attributes Meaning of a declarative sentence is a relation between utterances and described situations 12

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STO Ontology 13

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CONOPS 14

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Representing Queries (in terms of ElementaryInfon and Situation Type) 15 “Did an insurgent visit a weapons cache?” Expressible in pure OWL: InsurgentWeaponsCacheSituation ≡ Situation and (supportedInfon some (ElementaryInfon and (anchor1 some Insurgent) and (anchor2 some WeaponsCache) and (relation value visit))) “Which insurgents spied on a relative?” Not expressible in pure OWL, requires use of variables Rules are necessary, for instance: Situation(s) ∧ ElementaryInfon(i) ∧ Object(a1) ∧ Object(a2) ∧ Relation(spiedOn) ∧ supportedInfon(s, i) ∧ anchor1(i, a1) ∧ anchor2(i, a2) ∧ relation(i, spiedOn) ∧ Insurgent(a1) ∧ Person(a2) ∧ relative(anchor1, anchor2) → RelativeSpySituation(s)

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Answering Queries: Process 16

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A Running Example (based on SynCOIN) 17 Query: Which known insurgents are connected to people who have been to a weapons cache? WCSit ≡ Situation and (supportedInfon some (ElementaryInfon and (anchor1 some Insurgent) and (anchor2 some (Person and hasBeeonTo some WeaponsCache))) and (relation value isConnectedTo))) Initial facts:

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(1) Domain Inference 18 Infer implicit facts about the domain If necessary, add additional axioms to the dataset We added a few axioms to SynCOIN:

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(2) Situation Reasoning 19 Analyze situation type definitions (both in OWL and rules) Extract relevant relations used in definitions (visit and spiedOn in previous examples). Then extract relevant individuals. For each relation rel that is part of a situation type: For each pair of individuals a 1 and a 2 that are associated with each other by the property rel: 1. Assert that there is an individual s of RDF type sto:Situation 2. Assert that there is an individual i of RDF type sto:ElementaryInfon, supported by situation s 3. Assert the following facts: (i anchor1 a 1 ), (i anchor2 a 2 ) and (i relation rel)

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Example – cont. 20 Initial Graph: Current Answer:

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(3) Context Derivation 21 Derive the context for the answer Find relevant facts: all individuals and relations that are relevant to the situation that represents the answer to the query Derivation based on domain-independent rules, which backtrack OWL inference Currently: Property chain, sub-property, transitive property Example derivation rule for transitive property: For a situation s, and a query q, if s satisfies the query: For every fact (i 1 rel i 2 ) relevant to s and an individual i 3, if rel is a transitive property and if (i 1 rel i 3 ) and (i 3 rel i 2 ) are facts asserted in the knowledge base: 1. Add (i 1 rel i 3 ) and (i 3 rel i 2 ) as facts relevant to s.

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Example – cont. 22 Previous Step: Current Answer

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(4) Simplification 23 Context derivation is likely to produce a lot of “noise” We need to remove facts that are relevant to a situation, but that are not necessary to comprehend the graph Simplification based on domain-independent rules Example simplification rule for sub-property relation between relevant relations: For a situation s, and a query q, if s satisfies the query: For every relation r 1 and r 2 relevant to s, if r 1 is a sub-property of r 2 : For every two facts (i 1 r 1 i 2 ) and (i 1 r 2 i 2 ) that are both relevant to s: 1.Remove (i 1 r 2 i 2 ) from the context of s.

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Example – cont. 24 Previous step: Final answer:

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Conclusions 25 Objective: simplify answers to queries against RDF data Approach: use Situation Theory (Barwise, Perry, Devlin) Approximate Situation Theory formalization by using STO: Situation Theory Ontology, OWL and Rules Queries represented by STO:ElementaryInfon and STO:Situation Used OWL axioms to enhance reasoning about the domain Developed domain-agnostic rules for inferring relevant situations, situation types, relations and individuals in situations Developed context derivation rules Developed context simplification rules Developed a prototype and showed (on examples) that it works BaseVISor was used for inference To make it practical, “meta-reasoning” was needed.

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Future Work 26 More domain-independent inference rules needed Clustering Inference-driven generalization Machine Learning Feedback collected from GUI Concept/Link removal (affects transformation rules) Graphical arrangement (affects clustering) Scalability Very large scale graph databases Integration with data analytics Evaluate with analysts!

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Thank You

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