Visibility (geometry)

Abstract: Objective methods for assessing perceptual image quality traditionally attempted to quantify the visibility of errors (differences) between a distorted image and a reference image using a variety of known properties of the human visual system. Under the assumption that human visual perception is highly adapted for extracting structural information from a scene, we introduce an alternative complementary framework for quality assessment based on the degradation of structural information. As a specific example of this concept, we develop a structural similarity index and demonstrate its promise through a set of intuitive examples, as well as comparison to both subjective ratings and state-of-the-art objective methods on a database of images compressed with JPEG and JPEG2000. A MATLAB implementation of the proposed algorithm is available online at http://www.cns.nyu.edu//spl sim/lcv/ssim/.

Abstract: Polygon partitions Orthogonal polygons Mobile guards Miscellaneous shapes Holes Exterior visibility Visibility groups Visibility algorithms Minimal guard covers Three-dimensions and miscellany.

Abstract: Updates made to a central database (3), or to another partially replicated database (23-1) are selectively propagated to the partially replicated database (23-2) if the owner of the partially replicated database (23-2) is deemed to have visibility to the data being updated. Visibility is determined by use of predetermined rules stored in a rules database. Stored rules are assessed against data content of various tables that make up a logical entity, known as a docking object, that is being updated. The stored rules are assessed against data content of various tables that make up a docking object, not necessarily being the docking object that is being updated. The visibility rules of these related docking objects are recursively determined. Changes in visibility are determined to enable the central computer to direct the nodes to insert the docking object into its partially replicated database. The predetermined rules are in declarative form and specify visibility of data based upon structure of the data without reference to data content. Database objects and transactions have an associated visibility strength used to determine the visibility of a transaction to an object.

Abstract: The invention relates to a method of managing a database. The database includes a central database ( 3 ) and separate partially replicated databases ( 23 - a , 23 - b , 23 - c ). Each partially replicated database resides on a separate node ( 21 - a , 21 - b , 21 - c ). Each replicated database has an associated visibility strength. The method of managing a database determines the visibility strength of a partially replicated database to data being propagated, determines therefrom the visibility of the partially replicated database to the data being propagated, and propagates the data to a partially replicated database only if the node of the partially replicated database has visibility to the data.

Abstract: Database management method and system, for a database having a central database (1) and a plurality of partially replicated databases (21-a, 21-b, 21-c). The database management (9) method and system determine the visibility of a user of a separate replicated database to the central database from a set of visibility rules stored at a central location.