
158 ◾ Secure Data Provenance and Inference Control
10.4 Experiments
Our experiments were conducted on an IBM workstation with 8 × 2.5-GHz pro-
cessors and 32 GB RAM. Our prototype is efficient for both finding the shared
resource over an original provenance graph and evaluating the production rules
over the shared resource. We choose three conventions for preordering the produc-
tion rules: (1) the original ordering (O,O), (2) lowest to highest utility (LHO), and
(3) highest to lowest utility (HLO). We believe that provenance is more useful when
it is least altered. erefore, we define utility as
−
×
alteredtriples
original triples in G
q
0