36124114
Schema virtualization in object-oriented databases
A description is given of the concept and implementation techniques of schema virtualization in object-oriented databases. The objective of schema virtualization is to provide users with multiple views of a database. First, the notions of virtual classes and virtual schemata, which are natural extension of views in relational databases, is introduced. Then, procedures to convert a schema into a virtual one, as well as rules schemata and their conversion should satisfy, are discussed. The key issue of the design of virtual classes and virtual schemata is 'regarding procedures as objects'. Closure properties of classes and schemata are also discussed. Finally, several implementation techniques for realizing schema virtualization in Smalltalk-80 are presented.<<ETX>>
46335278
Tree-Structured Data Organization with Consecutive Retrieval Property
COMP2011 Aleksandar Ignjatovic 2005 c 2 Figure 1: A medieval copy of arguably the most influential textbook ever written, Eu-clid's Elements (Στoι χε´ια), from about 300 BC. It contains the oldest known algorithm recorded, Euclid's algorithm for computing the Greatest Common Divisor (GCD) of two natural numbers. Figure 2: First data structures: a Mesopotamian cuneiform tablet from about 3000 BC with an inventory list. Preface This booklet is not meant to be a textbook, but only a companion to the textbook that we use in this course, Cormen, Leiserson, Rivest and Stein's Introduction to Algorithms, the second edition. Its purpose is to help you read the appropriate sections of the textbook, and integrate it better with the rest of the course. It also adds a number of exercises not present in the textbook. Please read the textbook and do not rely on this supplement only.
1810071
Testing of Join Dependency Preserving by a Modified Chase Method
205099974
Organization of quasi-consecutive retrieval files
Abstract In 1972, Ghosh introduced the consecutive retrieval (CR) file organization. It is an efficient file organization in which all records pertinent to a query are consecutively stored on linear storage locations. In this paper, we introduce the quasi-consecutive retrieval (QCR) file organization. The QCR file organization is an extension of Ghosh's CR file organization and normally offers less redundancy. In the QCR file, all the records pertinent to each query are not necessarily stored consecutively, but rather they are stored within an area of the buffer size. In this paper, we discuss graph theoretic properties of CR files and QCR files by using the properties of interval graphs well known in graph theory. We provide a basic condition for the existence of a QCR file without redundancy for a given buffer size. By introducing redundant queries, such a condition is simplified. Furthermore, a heuristic computer algorithm is given to organize a QCR file with less redundancy for a given buffer size.
32965529
Interval Queries on Object Histories
Abstract The present paper introduces the notion of “interval queries” on object histories and explores a certain closure property. In particular, conditions are provided under which an interval query applied to object histories described by one “computational-tuple sequence scheme” (CSS) yields, as its answer, the set of all object histories which can be described by another CSS.
18193868
Interval Queries on Object Histories: Extended Abstract
This extended abstract introduces the notion of ’ interval queries ’ on historical data for objects (here, called ‘object histories’) and explores a certain closure property. As for describing historical data for objects, we use our mathematical model introduced in our earlier paper. The major construct in the model is a ‘computation-tuple sequence scheme’ (abbreviated CSS), which specifies the set of all possible ‘valid’ object histories for the same type of object. Interval queries are those queries which return an interval (history) from a given object history. We provide conditions under which an interval query applied to object histories described by one CSS yields, as its answers. the set of all object histories which can be described by another CSS.
3517036
Fixed Point Theory in Weak Second-Order Arithmetic
Abstract We develop a basic part of fixed point theory in the context of weak subsystems of second-order arithmetic. RCA0 is the system of recursive comprehension and Σ01 induction. WKL0 is RCA0 plus the weak Konig's lemma: every infinite tree of sequences of 0's and 1's has an infinite path. A topological space X is said to possess the fixed point property if every continuous function f:X→X has a point x ϵ X such that f(x) = x. Within WKL0 (indeed RCA0), we prove Brouwer's theorem asserting that every nonempty compact convex closed set C in R n has the fixed point property, provided that C is expressed as the completion of a countable subset of Q n. We then extend Brouwer's theorem to its infinite dimensional analogue (the Tychonoff-Schauder theorem for R N ) still within RCA0. As an application of this theorem, we prove the Cauchy-Peano theorem for ordinary differential equations within WKL0, which was first shown by Simpson without reference to the fixed point theorem. Within RCA0, we also prove the Markov-Kakutani theorem which asserts the existence of a common fixed point for certain families of affine mappings. Adapting Kakutani's ingenious proof for deducing the Hahn–Banach theorem from the Markov-Kakutani theorem, we also establish the Hahn-Banach theorem for seperable Banach spaces within WKL0, which was first shown by Brown and Simpson in a different way.
43363560
Adaptive Dynamic Voltage Scaling for Real-Time Systems
15731243
TORNADO: omnistereo video imaging with rotating optics
One of the key techniques for vision-based communication is omnidirectional stereo (omnistereo) imaging, in which stereoscopic images for an arbitrary horizontal direction are captured and presented according to the viewing direction of the observer. Although omnistereo models have been surveyed in several studies, few omnistereo sensors have actually been implemented. In this paper, a practical method for capturing omnistereo video sequences using rotating optics is proposed and evaluated. The rotating optics system consists of prism sheets, circular or linear polarizing films, and a hyperboloidal mirror. This system has two different modes of operation with regard to the separation of images for the left and right eyes. In the high-speed shutter mode, images are separated using postimage processing, while, in the low-speed shutter mode, the image separation is completed by optics. By capturing actual images, we confirmed the effectiveness of the methods.
18847598
A method for panoramic stereo image acquisition
One of the key technologies for one-to-many visual communication is panoramic stereo, in which stereoscopic images for arbitrary horizontal directions are presented to multiple users, according to their positions and postures. In this paper, one of the methods for capturing panoramic stereo motion pictures is proposed and evaluated, along with an experimentation. Through preliminary experimentation, we have confirmed the effectiveness of methods using a curved mirror.
7016005
Non standard Analysis in WKL0
Within a weak subsystem of second-order arithmetic WKL0, we develop basic part of non-standard analysis up to the Peano existence theorem.