Discusses the adaptive compression of computer files of numerical data whose statistical properties are not given in advance. A new lossless coding method for this purpose, which utilizes Adelson-Velskii and Landis (AVL) trees, is proposed. The method is effective to any word length. Its application to the lossless compression of gray-scale images…

Proposes a cost/benefit model coupled with a decision tree for determining normal forms, which are used in information systems development processes to group data into well-refined structures. The three primary variables that impact the benefits and costs of normalization (reduced anomalies, storage requirements, and transaction response times)…

Examines two models to study the consequences for coding efficiency of sample fluctuations, a specific type of error in the statistics on which data compression codes are based. The possibility that random fluctuation can be exploited for data compression is discussed. (six references) (KRN)

Discussion of multimedia libraries and the need for storage, indexing, and retrieval techniques focuses on the combination of computer vision and data mining techniques to model high-level concepts for image retrieval based on perceptual features of the human visual system. Uses fuzzy set theory to measure users' assessments and to capture users'…

Describes a method for compressing tomographic images obtained using Positron Emission Tomography (PET) and Magnetic Resonance (MR) by applying transform compression using all available dimensions. This takes maximum advantage of redundancy of the data, allowing significant increases in compression efficiency and performance. (13 references) (KRN)

Discusses a flexible, high performance subband coding system. Residual vector quantization is discussed as a basis for coding subbands, and subband decomposition and bit allocation issues are covered. Experimental results showing the quality achievable at low bit rates are presented. (13 references) (KRN)

Discusses traditional information retrieval through indexing terms and describes a document storage and retrieval system based on structured information, where the SGML document is transformed into Grove (Graph Representation of Property Values) and stored at an element level by an object-oriented database management system. Also discusses query…

Proposes a scheme of hierarchical piecewise linear approximation as an adaptive image pyramid. A progressive image coder comes naturally from the proposed image pyramid. The new pyramid is semantically more powerful than regular tessellation but syntactically simpler than free segmentation. This compromise between adaptability and complexity…

Discussion of office document search procedures focuses on variable bit-block compression (VBC) signature files and extends VBC signatures for document ranking. Topics include weighted VBC and aggregate VBC; word size, in bits, of term frequencies; storage and retrieval; logarithmic scaling and linear scaling; and ranking performance. (LRW)

Describes a detailed algorithm for fast text compression. Related to the PPM (prediction by partial matching) method, it simplifies the modeling phase by eliminating the escape mechanism and speeds up coding by using a combination of quasi-arithmetic coding and Rice coding. Details of the use of quasi-arithmetic code tables are given, and their…

Describes the design of optimal tree-structured vector quantizers that minimize the expected distortion subject to cost functions related to storage cost, encoding rate, or quantization time. Since the optimal design problem is intractable in most cases, the performance of a general design heuristic based on successive partitioning is analyzed.…

Discusses information retrieval and the use of binary trees as a fast access method for search strategies such as hashing. Proposes new methods based on compact binary trees that provide faster access and more compact storage, explains the theoretical basis, and confirms the validity of the methods through empirical observations. (LRW)

Discusses general problems of thesaurus construction theory and practice. Highlights include lexical control and its tools in various databases; natural language versus conceptual networks; systems approach; thesaurus versus classification, including associative relations; and thesaurus role in information storage and retrieval. (110 references)…

Presents a new image compression algorithm that employs some of the most successful approaches to adaptive lossless compression to perform adaptive online (single pass) vector quantization with variable size codebook entries. Results of tests of the algorithm's effectiveness on standard test images are given. (12 references) (KRN)

Evaluates the performance of different methods of data compression coding in several situations. Huffman's code, arithmetic coding, fixed codes, fast approximations to arithmetic coding, and splay coding are discussed in terms of their speed, memory requirements, and proximity to optimal performance. Recommendations for the best methods of…