Inference Web: Inference Web: Portable and Sharable Portable and Sharable Proofs for Hybrid Systems Proofs for Hybrid Systems Deborah L. McGuinness, Paulo Pinheiro da Silva and Bill MacCartney with Richard Fikes, Gleb Frank, Jessica Jenkins, Rob McCool, Yulin Li Knowledge Systems Laboratory Stanford University http://www.ksl.stanford.edu {dlm | pp} @ksl.stanford.edu
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Inference Web: Portable and Sharable Proofs for Hybrid Systems Deborah L. McGuinness, Paulo Pinheiro da Silva and Bill MacCartney with Richard Fikes, Gleb.
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Inference Web: Inference Web: Portable and Sharable Proofs Portable and Sharable Proofs
for Hybrid Systemsfor Hybrid Systems
Deborah L. McGuinness, Paulo Pinheiro da Silva and Bill MacCartney
with Richard Fikes, Gleb Frank, Jessica Jenkins, Rob McCool, Yulin Li
Provenance information - explain where source information: source name, date and author of last update, author(s) of original information, trustworthiness rating, etc.
Reasoning information - explain where derived information came from: the reasoner used, reasoning method, inference rules, assumptions, etc.
Explanation generation – provide abbreviated descriptions of the proof – may include reliance on a description of the representation language (e.g., DAML+OIL, OWL, RDF, …), axioms capturing the semantics, rewriting rules based on axioms, other abstraction techniques, etc.
Distributed web-based deployment of proofs - build proofs that are portable, sharable, and combinable that may be published on multiple clients, registry is web available and potentially distributed, …
Proof/explanation presentation - Presentation should have manageable (small) portions that are meaningful alone (without the context of an entire proof), users should be supported in asking for explanations and follow-up questions, users should get automatic and customized proof pruning, web browsing option, multiple formats, customizable, etc.
McGuinness, Pinheiro da Silva, and MacCartney, 2003 4
Inference WebInference Web
Framework for explaining reasoning tasks by storing, exchanging, combining, annotating, filtering, segmenting, comparing, and rendering proofs and proof fragments provided by reasoners. DAML+OIL/OWL specification of proofs is an interlingua for proof
interchange
Proof browser for displaying IW proofs and their explanations (possibly from multiple inference engines)
Registration for inference engines/rules/languages
Proof explainer for abstracting proofs into more understandable formats
Proof generation service for facilitate the creation of IW proofs by inference engines
Prototype implementation with Stanford’s JTP reasoner and SRI’s SNARK reasoner
“Weapons-grade nuclear material may be derived from uranium ore if refining technology is available, or it may be acquired from a black market source. Foobarstan is known to have either uranium ore or a black market source, but not both. Foobarstan will build a nuclear warhead if and only if it can obtain nuclear material, a detonator, and the bomb casing. A warhead and a missile, or a warhead and a truck, constitute a nuclear threat. Foobarstan has either a missile or a truck.”
QUESTION: Is Foobarstan a nuclear threat?
McGuinness, Pinheiro da Silva, and MacCartney, 2003 13
Example: proof by contradictionExample: proof by contradiction
McGuinness, Pinheiro da Silva, and MacCartney, 2003 14
Example: a proof treeExample: a proof tree
McGuinness, Pinheiro da Silva, and MacCartney, 2003 15
An example in FOLAn example in FOL
McGuinness, Pinheiro da Silva, and MacCartney, 2003 16
Registering SNARK: next stepsRegistering SNARK: next steps
Add support for ‘source’ and ‘author’ fields Match with IW-registered ontologies where possible
Standardize treatment of SNARK rewrites When do rewrites correspond to resolution, hyperresolution,
paramodulation?
Utilize SNARK rewrites for IW abstraction strategies
Consider tableaux approaches for explanation
Implement correct handling of SNARK procedural attachments SNARK includes procedural attachments for math, lists
User can define new procedural attachments on the fly
This constitutes an inference rule with an open-ended definition
Track variable bindings through course of proof
Integrate IW interface into SNARK standard release
McGuinness, Pinheiro da Silva, and MacCartney, 2003 17
Conclusion/Next StepsConclusion/Next Steps Proof specification ready for feedback/use
McGuinness, Pinheiro da Silva, and MacCartney, 2003 18
ExtraExtra
McGuinness, Pinheiro da Silva, and MacCartney, 2003 19
Proof browsing: an example Proof browsing: an example (1)(1)
Tools can be used for browsing IW proofs. The following example demonstrates the use of the IW Browser to visualize, navigate and ask follow-up questions.
Lets assume a Wines ontology:
Determination of the type of a concept or instance is a typical problem on the Semantic Web. A reasoner may ask either about the type of an object and may also ask if an object is of a particular type Example Query: (rdf:type TonysSoftShell ?X)
McGuinness, Pinheiro da Silva, and MacCartney, 2003 20
Proof browsing: An example Proof browsing: An example (2)(2)
Browsers can display portions of proofs.
Selecting premises users can navigate throughout proof trees.
Proof browsing: An example Proof browsing: An example (2)(2)
McGuinness, Pinheiro da Silva, and MacCartney, 2003 21
Trust DisclosureTrust Disclosure
IW proofs can be used:
to provide provenance for “lookup” information
to display (distributed) deduction justifications
to display inference rule static information
Trust DisclosureTrust Disclosure
McGuinness, Pinheiro da Silva, and MacCartney, 2003 22
Technical RequirementsTechnical Requirements annotate information with meta information such as source, date,
author, … at appropriate granularity level (per KB, per term, …)
explain where source information is from
explain where derived information came from
prune information and explanations for presentation (utilizing user context and information context for presentation)
provide a query language capable of expressing user requests along with filtering restrictions
provide a ubiquitous source annotation language
provide a ubiquitous proof language for interchange
Compare answers
propagate meta information appropriately (if I got something from a source I consider trusted and you consider me a trusted source, you may want to consider my source trusted as well)