Tài liệu Advances in Database Technology- P3 docx

... minimize the information loss in moving from clustering to clustering This information loss is given by We can also view the information loss as the increase in the uncertainty. Recall that Since H(A) ... Constrained Indexing and Query Indexing are proposed for efficient evaluation of this kind of queries at a central location. Several other indexing structures and algorithms for handling...

Ngày tải lên: 14/12/2013, 15:15

... relational databases into an XML format or to store the information in an XML object in a relational database, increasing the cost of e-business development. Moreover, specifying the mapping in the ... USA, 2002. J. Chomicki. Querying with intrinsic preferences. In Proc. of the Int. Conf. on Advances in Database Technology (EDBT), Prague, Czech Republic, 2002 R. Fagin, A. Lotem...

Ngày tải lên: 14/12/2013, 15:16

... designing the annotation specifications, considering the specifics of data integrity constraint checking, and ascertaining the impact on particular tools remain challenging (and interesting) tasks. focuses ... watermark. Computing and Handling Cardinal Direction Information 335 Fig. 3. Polygon clipping 3 Computing Cardinal Direction Relations Typically, in Geographical Information Systems a...

Ngày tải lên: 14/12/2013, 15:16

... between index nodes from corresponding trees in a priority queue and recursively (top-down) refining the search. In this case, using histograms, one could perform, in addition to the type of pruning ... the minimum bounding constraint, which increases the general overlap. In memory, for instance, RS verifies four times more objects than AC. Point-Enclosing Queries. Because queries lik...

Ngày tải lên: 24/12/2013, 02:18

... projection pushing and join reordering in terms of the treewidth of the join graph. (Note that the focus in [28] is on projection pushing in recursive queries; the non-recursive case is not investigated.) While ... section. 5 Improvements Using Domain Information So far we have discussed in what cases we do not need to normalize queries in the containment test, and in what cases w...

Ngày tải lên: 24/12/2013, 02:18

... process of integrating it into computing systems, some prior approaches have been proposed to map MEMS-based storage into disk-like devices. Using disk terminology, a cylinder is defined as the ... up memory by deleting a set of nodes such that the increase in TSSENC (see definition in Equation 6) is minimized and a certain factor of the memory allocated for cost modeling is freed. allows...

Ngày tải lên: 24/12/2013, 02:18

... and since each iteration is actually a generalized bargaining step, using a nested bargaining within a bargaining will only increase the number of exchanged messages. 4 Experimental Study In order ... be computed quickly, in a single pass over the data tuples in in the (arbitrary) order of their arrival. At any point in time, our query-processing algorithms can combine the maintained...

Ngày tải lên: 24/12/2013, 02:18

... see that as time advances, PJoin maintains an almost steady output rate whereas the output rate of XJoin drops. This decrease in XJoin output rate occurs because the XJoin state increases over ... of XJoin. We differ in that no previous work incorporates both constraint-exploiting mech- anism and adaptivity into join execution logic itself. Unlike the k-constraint- exploiting algori...

Ngày tải lên: 24/12/2013, 02:18

... to maintain than a LIST without any indices or the T-INDEX. For 10000 distinct values, the G-INDEX with 50 groups is faster than the T-INDEX and faster than maintaining a sliding window using ... watermark. On Indexing Sliding Windows over Online Data Streams 729 7 Conclusions and Open Problems This paper began with questions regarding the feasibility of maintaining sliding window indices. .....

Ngày tải lên: 24/12/2013, 02:18

... could be obtained through mining or just from in- formation retrieval. Data mining is an important tool in making the web more intelligent. That is, data mining may be used to mine the data on ... with work on information systems engineering involving, for example, databases and web services. E. Bertino et al. (Eds.): EDBT 2004, LNCS 2992, pp. 3–16, 2004. © Springer-Verlag Berlin Heidelbe...

Ngày tải lên: 14/12/2013, 15:15