Combinatorial signatures for data encoding and searching
CA 2000006 C · Owner: Chang, Walter W. · Inventors: Chang, Walter W.; Schek, Hans G.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
This invention encodes information (such as the field values of a database record, or the words of a text document) so that the original information may beefficiently searched by a computer. An information object is encoded into a small "signature" or codeword using a method. A base or "leaf" signature S1 34 is computed by a known technique such as hashing. The logical intersection (AND) ofeach possible combination of pairs of bits of the base signature is computed and the, result is stored as one bit of a longer combinatorial signature CS1 42. The bit-wise logical union (bit-OR) of the combinatorial signatures of a group of records produces a second-level combinatorial signature CS2 52 …
Read the whole patent
Listed from its CIPO record in Patent Yard's archive of Canadian patents past their term. Its claims, description and drawings are in the CIPO record and on Google Patents, and the Claude kit works from them.
Why it's free to use
- Filed October 2, 1989 and granted July 12, 1994. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended October 2, 2009.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by October 2, 2011.
- We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
Timeline
Timeline From CIPO dates
Sources & verification
Official CIPO records
Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.