1. McGuinness Feb 28, 2002 1 Explanation for Query Answering: Logical Foundations Deborah McGuinness Associate Director and Senior Research Scientist Knowledge Systems Laboratory Stanford University dlm@ksl.stanford.edu With support from Richard Fikes, Jessica Jenkins, Gleb Frank, Yulin Li, Steve Wilder

2. McGuinness Feb 28, 2002 2 Outline n Background and Motivation n Needs * IR - Input Requested for list and priorities n Issues * IR n Action items / Next Steps *IR

3. McGuinness Feb 28, 2002 3 What is an explanation? From Merriam Webster: 1 a : to make known b : to make plain or understandable 2 : to give the reason for or cause of 3 : to show the logical development or relationships of intransitive senses : to make something plain or understandable For operational computer systems, we can consider an explanation to be a justification of system belief or a justification of a statement.*

4. McGuinness Feb 28, 2002 4 Simple Motivating Example n Why is Stanford a school in Santa Clara County (or why is Stanford an instance of the class school and why is Stanford in Santa Clara County)? n Possible answers: l Because I told you so and I am always right l Because authoritative source XYZ says so l Because source XYZ and PQR says so (& no awareness of contradictions) l Because authoritative reasoner deduced it l Because authoritative reasoner deduced it as follows: Because Stanford is believed to be a University (stated in in authoritative source S1) and all universities are schools (stated in authoritative source S2) and if x isa y and y is a z, then x isa z

5. McGuinness Feb 28, 2002 5 Justifications n Necessary components for a simple justification foundation: l Inference rule l Bindings for variables in the inference rule l Source of information n Sample Inference Rule InheritanceX => YY=> Z X => Z n Note: Follow-up questions follow from logical form of rule

6. McGuinness Feb 28, 2002 6 Example InheritanceX => YY=> Z X => Z (inference list available for some systems: CLASSIC, DAML+OIL, …) Why is Stanford an instance of School? Sample Application: Rule: Inheritance Bindings: from query X=Stanford, Z=School, Y=University Source X=>Y db1 Y=>Z daml ontology library organizations

7. McGuinness Feb 28, 2002 7 One Approach n For any statement expressible in your kb, allow a user to ask why the system believes it n Some system (possibly a separate explainer system) generates a justification for the statement (alternative, present a list of inferences(SHAKEN), present some form of (abstracted) proof tree,…) n Justifications are first class objects so that follow-up questions may be asked about statements (and about inference rules) n Justifications may be viewed as portable, exchangeable objects that facilitate system interaction n Background work done in normalize/compare DL systems, tableaux-based reasoning systems, model elimination reasoners (ATP/JTP), …

8. McGuinness Feb 28, 2002 8 (RKF) Needs for Justifications n People need a justification in order to: l Trust the validity of a statement l (Re)use an answer l Share answers and/or share deductions across systems ** l Debug surprising information l Maintain knowledge bases l Train people on knowledge bases l Train programs (e.g., Disciple) l Provide customer service support l Present contradictions more usefully (defend how system determined contradictions) l Support for kb updates due to information changes l Distinguish between types of knowledge (e.g., lookup vs. deduction) l Support adjudication between hypotheses (helps in handling non- monotonically changing kbs, conflicting kbs, etc.)

9. McGuinness Feb 28, 2002 9 Challenges/Issues n Proof traces quickly become hard to understand and large n Although techniques exist to help manage large presentations of proofs (atomic justifications, stepwise explanation, automatic follow-up questions, …) these may not be enough n Management techniques for presenting underlying reasoning may not be appropriate (e.g., tableaux methods are unintuitive….) n Explanations may be needed at many levels of abstractions – for novice users, advanced users, simple agents, sophisticated agents, etc. n Portable proofs need to understand the other systems inference rules n Extra challenges from contradictions, distributed knowledge sources, distributed authoring, sound & complete vs. incomplete vs. heuristic strategies, … n …

10. McGuinness Feb 28, 2002 10 Next Steps n Working Group? n Maintain Needs and Issues list and prioritize n Maintain RKF researcher list – input from Clark, interest from Tecuci, Mehrotra n Publish inference ruleset(s) for portable proofs n …

11. McGuinness Feb 28, 2002 11 Extras

12. McGuinness Feb 28, 2002 12 Why Query Answering (and not just information retrieval)

13. McGuinness Feb 28, 2002 13

14. McGuinness Feb 28, 2002 14 Sometimes it is better… Google Searched the web for universities in santa clara county. Results 1 - 10 of about 13,500.universitiesinsanta clara county PlanningPlanning... San Jose State University; Santa Clara University; Silicon Valley... Sonoma County. Empire College; Santa Rosa Junior College;... Colleges and Universities Beyond the Bay... ** Santa Clara County Network for a Hate-Free CommunitySanta Clara County Network for a Hate-Free Community... *Universities include Stanford University, Santa Clara University, San Jose State... Copyright 2001 Santa Clara County ISD Web Development Team. College and Universtity Links - Santa Clara County LibraryCollege and Universtity Links - Santa Clara County Library... University Links This guide to colleges and universities can be sorted by name, state, and type... Santa Clara County Library, 1095 N. 7th Street, ** Master Gardeners of Santa Clara County – MissionMaster Gardeners of Santa Clara County – Mission... system was established to encourage state universities to better serve the agricultural... Santa Clara County As volunteer representatives of the Related Links - Santa Clara Transportation AuthorityRelated Links - Santa Clara Transportation Authority... Clara, County of Santa Clara County Office of Education Saratoga... Page Downtown San Jose Santa Cruz Silicon Valley... Bay Area Colleges And Universities. California Colleges & Universities Contact Directory RegionCalifornia Colleges & Universities Contact Directory Region, Community Health Library of Los Gatos - Web Resources, San Francisco East Bay Education and Research, Santa Clara University : Convocation Speech 2000 : The Valley..., City of Santa Clara, California, Plans and Ordinances;. Daniel Roest Interview,Community Health Library of Los Gatos - Web ResourcesSan Francisco East Bay Education and ResearchSanta Clara University : Convocation Speech 2000 : The Valley... Daniel Roest Interview

15. McGuinness Feb 28, 2002 15 Sometimes it is worse… Google Searched the web for sources of advanced degrees in santa clara county. Results 1 - 10 of about 1,560.sourcesofadvanceddegreesinsanta clara county Catholic Charities Santa ClaraCatholic Charities Santa Clara... by professional counselors with advanced degrees in social work or... 2002 Catholic Charities of Santa Clara County, 2625 Zanker Road, San Jose... Community Health Library of Los Gatos - Web ResourcesCommunity Health Library of Los Gatos - Web Resources... Santa Clara County Department of Environmental... a jump station for sources of information on... research and offering advanced degrees in the... San Francisco East Bay Education and ResearchSan Francisco East Bay Education and Research... for graduate degrees.... second to Santa Clara and that... laboratories, Alameda County is a... energy sources, combustion technology... electronics, advanced materials... Santa Clara University : Convocation Speech 2000 : The Valley... Santa Clara University : Convocation Speech 2000 : The Valley...... The reason Santa Clara has started the... can become sources of threat and... come here for advanced degrees, immigrants make... idyllic Marin County don't... City of Santa Clara, California, Plans and Ordinances,...... is 41 degrees. Rain is... cost-effective sources including cogeneration... of the County, Santa Clara's taxable retail... Store, National Advanced Systems... Daniel Roest Interview, Calptect, Health Statistics Eritreans at CSULB - Our BylawsCity of Santa Clara, California, Plans and Ordinances,... Daniel Roest Interview CalptectHealth Statistics Eritreans at CSULB - Our Bylaws

16. McGuinness Feb 28, 2002 16 Geog-Containmnt:GeogContains(A,C)GeogContains(C,D) GeogContains(A,D)

17. McGuinness Feb 28, 2002 17Issues l Collaboration among distributed teams l Interconnectivity with many systems/standards l Analysis and diagnosis l Scale l Versioning l Security l Ease of use l Diverse training levels /user support l Presentation style l Lifecycle l Extensibility