Abel2007enabling presented by Tim Lebo 25 sept 2008 Shangguan 4

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• Question is for the Presentation: Abel2007enabling presented by Tim Lebo 25 sept 2008
• Question is asked by: Zhenning Shangguan
• The Question is: About evaluation part. The author only gave the response time when increasing the number of FROM and WHERE clauses. Is this response time acceptable? What portion does it take in the overall query response time? Since the RDF queries are expanded, will this bring extra overheard to the query processing and execution? Moreover, the author should compare with response time resulting from other access control mechanisms, as stated in section 3.

About evaluation part. The author only gave the response time when increasing the number of FROM and WHERE clauses. ONE: Is this response time acceptable? TWO: What portion does it take in the overall query response time? THREE: Since the RDF queries are expanded, will this bring extra overheard to the query processing and execution? FOUR: Moreover, the author should compare with response time resulting from other access control mechanisms, as stated in section 3.

Response:ONE: it depends. TWO: Assuming "it" is referring to the "policy pre-filtering and query expansion" presented in this approach, the portion "it" takes is not determined from the presented evaluation and /should be/. THREE: This question is addressed by the evaluation presented. Consider the gray dotted line (0 extra from clauses) in condition A (no MINUS operator removing deny conditions) as the number of WHERE clauses increases. The response time is exhibiting a linear growth in terms of the additional WHERE clauses that result from the query expansion. FOUR: Agreed. They should also compare response time of WITH and WITHOUT access control for the same queries. I will address this at the end of my talk.warning.pngString representation ONE: it depends. TWO: Assuming "it" is ref […] I will address this at the end of my talk. is too long.