Panel on Knowledge Repositories

1. Panel on Knowledge Repositories Organizer: Chitta Baral chitta@asu.edu Panel members: Michael Gelfond Vladimir Lifschitz

2. What do I mean by a knowledge repository? • A collection of knowledge modules. • That can be used by knowledge base developers. • Similar to Java or C++ libraries. • But building a knowledge repository • poses a lot more challenges; • to be discussed in later slides. • and will be much larger in size.

3. Why do we need knowledge repositories? • Reasoning with Knowledge and learning knowledge is the essence of AI. • Evident from the meaning of “intelligence” in a dictionary • Lot of progress in Knowledge Representation. • Especially with respect to AnsProlog (logic programming with answer set semantics) • A core language with many suggested extensions • A large body of theoretical results • Many implementations • Many applications

4. But we need to … • Go beyond • Writing knowledge axioms from scratch • Small knowledge bases • Be able to build large knowledge bases without starting from scratch. • Make it easier to build knowledge bases. • Reuse knowledge modules developed by others. • Make knowledge bases part of most AI systems.

5. Applications and Impacts of Knowledge Repositories • Question answering systems • Text: John took a flight from Rome to Paris 6 hours ago? • Question: Where is John now? Where is his wife who saw him off at the airport? • Any system that needs to use common-sense reasoning. • Any system that needs to reason with knowledge in one or many domains.

6. Is this a blue sky dream? • Not really? • Wordnet (http://wordnet.princeton.edu/) • An electronic repository of words and their meanings has been very useful. • It took a lot of work to get built. • A knowledge repository will need a lot more work.

7. What does building a Knowledge Repository involve? • A large body of Knowledge modules possibly grouped in packages • Common sense modules • Domain specific modules • High level modules: actions, time, space, etc. • Methodology to facilitate building modules • Inheritance, encapsulation, modeling languages, etc. • Interface mechanisms similar (in functionality) to interface mechanisms in Java, C++ etc.

8. Existing efforts: CYC • CYC: a pioneer • Possible IP and legal issues. • subsets (ResearchCYC) need signing of a lot of legal documents. • CYC’ s language is proprietary and untested outside of CYC. (mostly unpublished outside). • But if this can be overcome, then it could be a good starting or reference point.

9. Existing efforts: CYC • CYC : our effort :: Celera effort : Open Genomics effort • We would like the whole community to be involved in building. • Openmind: collects NL knowledge over the web.

10. Existing effort: SUMO and MILO • http://www.ontologyportal.org/ • SUMO and MILO are freely available • SUMO • http://cvs.sourceforge.net/viewcvs.py/*checkout*/sigmakee/KBs/Merge.kif?rev=1.3 • MILO • http://cvs.sourceforge.net/viewcvs.py/*checkout*/sigmakee/KBs/Mid-level-ontology.kif?rev=1.2

11. SUMO • SUMO (Suggested Upper Merged Ontology) • Based on first-order logic. • It incorporates • elements of John Sowa's upper ontology • Russell and Norvig's ontology • PSL (Process Specification Language), • Casati and Varzi's theory of holes, • Allen's temporal axioms, etc. • It has a nice browsing and editing tools, and • Inference and Ontology management system • http://sigmakee.sourceforge.net/

12. MILO (MId-Level Ontology) • Aim is to be a bridge between the abstract content of the SUMO and the rich detail of the various domain ontologies. • In progress, incomplete. • Contains a Description Logic Knowledge base • Class-subclass • Class-instances • Relations

13. Going beyond SUMO and MILO? • Why? • Both SUMO and MILO are based on first-order logic. • Need ways to express defaults and exceptions, • need ways to express problem solving queries, such as planning, diagnosis, etc. • …

14. Recall: What do we need? • A large body of Knowledge modules possibly grouped in packages • Common sense modules • Domain specific modules • High level modules: actions, time, space, etc. • Methodology to facilitate building modules • Inheritance, encapsulation, modeling languages, etc. • Interface mechanisms similar (in functionality) to interface mechanisms in Java, C++ etc.

15. Coupling modules and inference mechanism • AnsProlog versus ASP • AnsProlog -- Programming in logic with answer sets • ASP – seems to be focused on the generate and test problem solving • Need modules of various kinds • Is ancestor(john,mary)? (Prolog style) • Find a plan (ASP style) • Find a schedule (CLP) • Different kinds of modules may need different inference mechanisms

16. Next Steps, challenges • Lets look at the AAAI’06 Spring Symposium CFP.

17. AAAI’06 Spring symposium • Title: Formalizing and Compiling Background Knowledge and its applications to Knowledge Representation and Question Answering. • Organizing Committee: • Chitta Baral (chitta@asu.edu) • Alfredo Gabaldon (alfredo.gabaldon@nicta.com.au) • Michael Gelfond (mgelfond@cs.ttu.edu) • Joohyung Lee (appsmurf@cs.utexas.edu) • Vladimir Lifschitz (vl@cs.utexas.edu) • Steve Maiorano (stevemai@mac.com) • Sheila McIlraith (sheila@cs.toronto.edu) • Leora Morgenstern (leora@steam.stanford.edu)

18. CFP: Requests contributions that are • A: formalizations (knowledge modules) of background knowledge in specific domains as well as, • B: papers addressing general challenges such as formalizing background knowledge for use by multiple users on multiple reasoning tasks. • Interface issues, reuse, etc.

19. A: Knowledge module papers • No restriction on the domain to be formalized or on the level of specificity • Suggested common format • A knowledge base (KB) written in English. • Examples of informal consequences of KB, preferably accompanied by some explanations, including defaults and other commonsense knowledge not directly mentioned in KB but needed to produce the desired consequence.

20. A: Knowledge module papers (cont.) • Information about which logic/language is used in formalizing it. (Syntax, semantics, and where the reasoning system is available.) • The formalization • Short description on how the formalization can be tested using the reasoning system.

21. Existing knowledge encoded in AnsProlog • Small AnsProlog programs (not quite modules – don’t have modular interface) • Knowledge Representation, Reasoning and Declarative Problem Solving. Baral • Various surveys: Niemela et al.; Gelfond and Leone. Etc. • Larger programs • RCS-USA Advisor (http://www.krlab.cs.ttu.edu///Software/) • www.baral.us/bookone/ • Vladimir is collecting a list of ASP applications.

22. Further ideas for submissions of type A. • At various abstractions • Actions, time, space, etc. • Various domains • Travel, terrorism, etc. • Further collections and catalogues of existing encoded knowledge.

23. B: Interface and Engineering issues • How to call a module from another module: interface syntax and semantics • Object oriented issues • Encapsulation • Classes, sub-classes, Inheritance • Polymorphism • Modeling language

24. Some initial steps on Interface issues • Towards an Integration of Answer Set and Constraint Solving. Baselice, Bonatti and Gelfond. ICLP’05 • A language for modular ASP. Tari, Baral, & Anwar. ASP’05. • Enhancing ASP with templates. Ianni et al. NMR’2004. • Personal communication. Lifschitz. • F-logic papers. Kifer et al.

25. Challenges vis-à-vis C++ and Java libraries • Number of modules could be much larger and much varied than classes and methods in Java libraries • Multiple AnsProlog sub-languages, each with a different reasoning mechanism • Various sources of knowledge – some would be learned • Initially a smaller number of developers • Language is still evolving (core is there)

26. More info on the symposium • Symposium Dates: • March 27-29 2006. • AAAI site: • http://www.aaai.org/Symposia/Spring/2006/sssparticipation-06.pdf • Symposium cite • http://www.public.asu.edu/~cbaral/aaai06-ss/ • Deadlines: • Submission: October 7, 2005 (extended to October 21st) • Response: November 4, 2005 • Camera ready due at AAAI: January 27, 2006 • Symposium date: March 27-29 2006.

27. Thank You