0.25
0.5
0.75
1.25
1.5
1.75
2
Certain Answers for SPARQL with Blank Nodes
Published on Nov 22, 20182727 Views
Blank nodes in RDF graphs can be used to represent existential values known to exist but whose identity remains unknown. A prominent example of such usage can be found in the Wikidata dataset where, e
Related categories
Chapter list
Certain Answers for SPARQL with Blank Nodes00:00
Example 1: Beowulf was written by somebody00:07
The meaning of blank nodes - 100:29
The meaning of blank nodes - 200:40
Example 2: Who killed her? - 101:00
Example 2: Who killed her? - 201:16
Questions02:15
Example 3: Women not killed by athletes - 102:36
Example 3: Women not killed by athletes - 202:55
Example 3: Women not killed by athletes - 303:13
Example 3: Women not killed by athletes - 404:17
Example 3: Women not killed by athletes - 504:44
Recall the complexity gap!04:55
The studied solution05:17
Approximating certain and possible answers05:42
Approximation05:57
Over approximation of poss(R on S) ∼ poss(R) on poss(S) 05:59
Under approximation of cert(R on S) ∼ cert(R) on cert(S) 06:13
Over approximation of poss(R − S) ∼ poss(R) − cert(S) 06:18
Under approximation of cert(R − S) ∼ cert(R) − poss(S)06:31
Translation from SPARQL to Relational Algebra06:40
Translation to fix queries06:57
Experiments07:34
General evaluation settings07:44
Basic unification experiments - 107:57
Basic unification experiments - 208:06
Basic unification experiments - 308:19
Basic unification experiments - 408:33
Wikidata survey: Numbers of Wikidata use-case queries09:06
Evaluation of Wikidata example queries10:50
Conclusions11:27