Information Technology

  2010 MAR 16 - (VerticalNews.com) -- "Based on stereographic projection (SP), a novel and systematic three-dimensional (3D) objects' intersection predicate theory is inferred and formularized. The theory is deduced from the intersection of quasi-convex bodies," researchers in Changchun, People's Republic of China report.

  "Since composite mapping has omnidirectional one-to-one mapping properties for any quasi-convex bodies, they can be accurately projected to the equatorial plane, and their intersection predicate can be simplified into two dimensions. Those predicate conclusions are further applied to common polyhedrons by the introduction of the radial dividing point concept. 'Point inclusion' and 'line traversing' are mathematically abstracted as the primary intersection predicate types for all kinds of 3D objects, even including curved line and curved surface. As a special case of 'point inclusion', 'polyhedron entirely included' is also pointed out," wrote S.Q. Zhang and colleagues, Chinese Academy of Science ...read more

  2010 MAR 16 - (VerticalNews.com) -- According to a study from Haifa, Israel, "When integrating geo-spatial data sets, a join algorithm is used for finding sets of corresponding objects (i.e., objects that represent the same real-world entity). This article investigates location-based join algorithms for integration of several data sets."

  "First, algorithms for integration of two data sets are presented and their performances, in terms of recall and precision, are compared. Then, two approaches for integration of more than two data sets are described. In one approach, all the integrated data sets are processed simultaneously. In the second approach, a join algorithm for two data sets is applied sequentially, either in a serial manner, where in each join at least one of the joined data sets is a single source, or in a hierarchical manner, where two join results can be joined. For the two approaches, join algorithms are given. The algorithms are designed to perform well even when location of objects are imprecise and each data set represents only some of the real-world entities. Results of extensive experiments with the different approaches are provided and analyzed. The experiments show the differences, in accuracy and efficiency, between the approaches, under different circumstances," wrote E. Safra and colleagues ...read more

  2010 MAR 16 - (VerticalNews.com) -- "In this paper, we introduce a system able to generate an intuitive, human-like linguistic description of the topological relationships between two objects. The description includes approximate terms commonly found in daily communications," scientists in Guelph, Canada report.

  "It attempts to capture the essential characteristics of the relationships, while leaving out superfluous and possibly overwhelming detail. The objects are 2-D image objects. They need not be convex, nor connected, and they may have holes in them. Each description is built around Allen relations, based on information extracted from F-histograms. It consists of a topological component that indicates the primary topological relationships, directional estimates of where these relationships are most prominent, and a self-assessment component which reflects the complexity of the situation," wrote P. Matsakis and colleagues, University of Guelph ...read more