نتایج جستجو برای: view selection
تعداد نتایج: 572813 فیلتر نتایج به سال:
View selection is important in many data-intensive systems e.g., commercial database and data warehousing systems to improve query performance. View selection can be de ned as the process of selecting a set of views to be materialized in order to optimize query evaluation. To support this process, di erent related issues have to be considered. Whenever a data source is changed, the materialized...
In this paper, we investigate the problem of view selection for workloads of conjunctive queries under bag semantics. In particular we aim to limit the search space of candidate viewsets. In that respect we start delineating the boundary between query workloads for which certain restricted search spaces suffice. They suffice in the sense that they do not compromise optimality in that they conta...
For the first time, we formulate a flexible density function from the selection mechanism viewpoint (see, for example, Bayarri & DeGroot (1992) and ArellanoValle et al. (2006)) which possesses nice biological and physical interpretations. The new density function contains as special cases many models that have been proposed recently in the literature. In our model, we assume that the number of ...
In this paper, I respond to arguments proposed by Brunnander in this journal issue concerning my position regarding the Creative View of natural selection (Razeto-Barry & Frick, 2011). Brunnander argues that (i) the Creative View we defend does not serve to answer William Paley's question because (ii) Paley's question is "why there are complex things rather than simple ones" and (iii) natural s...
Data Warehousing (DW) systems store materialized views, data marts and data cubes, and provide nicely data exploration and analysis interfaces via OnLine Analytical Processing (OLAP) (Gray et al., 1997) and Data Mining (DM) tools and algorithms. Also, OnLine Analytical Mining (OLAM) (Han, 1997) integrates the previous knowledge discovery methodologies and offers a meaningfully convergence betwe...
The explosive popularity of social media produces mountains of high-dimensional data and the nature of social media also determines that its data is often unlabelled, noisy and partial, presenting new challenges to feature selection. Social media data can be represented by heterogeneous feature spaces in the form of multiple views. In general, multiple views can be complementary and, when used ...
In order to facilitate query processing, the information contained in data warehouses is typically stored as a set of materialized views. Deciding which views to materialize presents a considerable challenge. The task is to select from a very large search space a set of views that minimizes view maintenance and query processing costs. Heuristic methods have been employed to find near optimal so...
We address the problem of multi-view multi-target tracking using multiple stationary cameras in the application of hockey tracking and test the approach with data from two cameras. The system is based on the previous work by Okuma et al. [50]. We replace AdaBoost detection with blob detection in both image coordinate systems after background subtraction. The sets of blob-detection results are t...
Streamline visualization can be formulated as the problem of streamline placement or streamline selection. In this paper, we present an importance-driven approach to view-dependent streamline selection that guarantees coherent streamline update when the view changes gradually. Given a large number of randomly or uniformly seeded and traced streamlines and sample viewpoints, our approach evaluat...
OLAP applications use precomputation of aggregate data to improve query response time. While this problem has been well-studied in the recent database literature, to our knowledge all previous work has focussed on the special case in which all aggregates are computed from a single cube (in a star schema, this corresponds to there being a single fact table). This is unfortunate, because many rea...
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