Efficient web searching using temporal factors
We study the issues involved in the design of algorithms for performing information gathering more efficiently, by taking advantage of anticipated variations in access times in different regions at different times of the day or week. We look at the problem theoretically, as a generalisation of single processor sequencing with release times and deadlines, in which performance times (lengths) of the tasks can change in time. The new problem is called Variable Length Sequencing Problem (VLSP). We show that although the decision version of VLSP seems to be intractable in the general case, it can be solved optimally for lengths 1 and 2. This result opens the possibility of practicable algorithms to schedule searches efficiently when expected access times can be categorised as either slow or fast. Some algorithms for more general cases are examined and complexity results derived. (C) 2001 Elsevier Science B.V. All rights reserved.
web searching sequencing matching approximation random