Search

A novel and fully scalable model for enabling a scalable video codec to achieve optimality over a wide range of bit rate, resolution and frame rate is presented. Findings reveal the efficiency of the proposed model.

Bitmap indices are efficient for answering queries on low-cardinality attributes. In this article, we present a new compression scheme called Word-Aligned Hybrid (WAH) code that makes compressed bitmap indices efficient even for high-cardinality attributes. We further prove that the new compressed bitmap index, like the best variants of the B-tree index, is optimal for one-dimensional range queries. More specifically, the time required to answer a one-dimensional range query is a linear function of the number of hits. This strongly supports the well-known observation that compressed bitmap indices are efficient for multidimensional range queries because results of one-dimensional range queries computed with bitmap indices can be easily combined to answer multidimensional range queries. Our timing measurements on range queries not only confirm the linear relationship between the query response time and the number of hits, but also demonstrate that WAH compressed indices answer queries faster than the commonly used indices including projection indices, B-tree indices, and other compressed bitmap indices. Categories and Subject Descriptors: E.4 [Coding and Information Theory]: Data compaction and compression; H.3.1 [Information Systems]: Content Analysis and Indexing--Indexing methods General Terms: Performance, Algorithms Additional Key Words and Phrases: Compression, bitmap index, query processing

A rate-distortion framework is used to define a displacement vector field estimation technique for use in video coding. This technique achieves maximum reconstructed image quality under the constraint of a target bit rate for the coding of the vector sequence. The technique may be adapted so as to limit its smoothing effect to homogeneous areas and avoid highly textured areas and edges. Use of this technique is evaluated for two application areas in which the need for high compression of displacement vector fields is particularly acute. The first is motion field coding for very-low-bit-rate image sequence transmission, as in video-phone applications. The second application area is coding for the transmission of dense disparity fields. This is needed for the generation at the receiver of intermediate viewpoints through spatial interpolation. It is also needed in a number of other applications requiring accurate depth knowledge, including three-dimensional medical data transmission and transmission of scenes to be postprocessed using depth-keyed segmentation. Experimental results illustrating the performance of the proposed technique in these application areas are presented and evaluated. Index Terms - Depth-map coding, rate-distortion theory, vector field coding, very-low-bit-rate coding.

Fully parallel modified signed-digit arithmetic operations are realized based o redundant bit representation of the digits proposed. A new truth-table minimizing technique is presented based on redundant-bit-representation coding. It is shown that only 34 minterms are enough for implementing one-step modified signed-digit addition and subtraction with this new representation. Two optical implementation schemes, correlation and matrix multiplication, are described. Experimental demonstrations of the correlation architecture are presented. Both architectures use fixed minterm masks for arbitrary-length operands, taking ful advantage of the parallelism of the modified signed-digit number system and optics. Keywords: Modified signed-digit arithmetic, redundant bit representation, truth table minimizing digital optical computing

A new procedure for time mapping of uniform dependence algorithms with nested loops into (k - 1)-dimensional processor arrays is reported. The approach, which is based on the Hermite normal form of the mapping matrix, obtains the essential but sufficient circumstances under which conflict-free mapping can take place. By considering the derived conditions, the problem is thus recast into an integer programming problem.

Recent advances in algorithms and the speed of computer hardware now allow programmers to compute the values of constants such as pi to billions of decimal places. Functions can also be computed to a large number of decimal places. By performing simple conversions on the digits, it is possible to create bitmap images generated from the digits. The purpose of this article is to issue a challenge to the readership of JRM to find interesting images generated using this data.

New types of multiple-bit upset (MBU) modes have been identified in high-density DRAMs (16 Mbit and 64 Mbit). The identification of the mechanisms responsible for the new modes is based on detailed physical bit-map analysis.