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Reconciling facts: how to check the consistency of facts
created from web crawling
Dr Rob StaceyTrue Knowledge Ltd.
True Knowledge Open Domain question answering Semantic query language Structured and Unstructured
knowledge acquisition >300 million facts 20k+ classes Billions of inferred facts
Answering a question Query processing
Triple representation[london] [is an instance of] [city]
Temporal knowledge represented by “facts about facts” [fact: [“123”]] [applies for timeperiod] [<1970 onwards>]
Richness within entity representation• “parametered” objects
[integer: [“8128”]] [group: [london]; [san francisco]]
* Actually 4 with negative relation
Reconciliation- What system assessment can do
Accept incoming knowledge Contradict knowledge Make knowledge superfluous
Uses user assessments and scoring to determine which facts are believed
How assessment works Run a negative version of the query
• [married] ~[applies to] [madonna] If the query is unknown the fact is
new to the knowledge base If the result is no then fact is either
superfluous or an endorsement If the result is yes the there is a
contradiction
Fact already proven The assertion may simply be an
existing fact – if so more weight is added to the truth of that fact
If the fact is different then it is superfluous to the system, though still valid is it removes the need for inference.
Contradiction One of two facts must be wrong
Assessment scoring decides which fact to believe
The loser is contradicted and not believed or used in query processing