The provably NP-hard problem of finding optimal piecewise linear approximation for images is extended from 1D curve fitting to 2D surface fitting by a dual-agent algorithm. The results not only yield a storage-efficient codec for range, or intensity, images but also a surface triangulation technique to generate a succinct, accurate and visually pleasant 3D visualization model. Compared with the traditional piecewise linear image coding (PLIC) algorithms, triangulation of a range image is more adaptive due to conformity of the shape, orientation and size of triangles with the image contents. The triangularization algorithm presented here differs from previous approaches in that it strives to minimize the total number of triangles (or vertices) needed to approximate the image surface while keeping the deviation of any intensity value to within a prescribed error tolerance. Unlike most methods of bottom-up triangularization, which could bog down before any mesh simplification even begins, this algorithm fits the surface in a top-down manner, avoiding the generation of most unnecessary triangles. When combined with an efficient 3D triangulation-encoding scheme, the algorithm achieves compact code length with guaranteed error bound, thus providing a more faithful representation of all image features. A variety of benchmark test images have been experimented with and compared.

We examine progressive lossy to lossless compression of medical volumetric data using three-dimensional (3D) integer wavelet packet transforms and set partitioning in hierarchical trees (SPIHT). To achieve good lossy coding performance, we describe a 3D integer wavelet packet transform that allows implicit bit shifting of wavelet coefficients to approximate a 3D unitary transformation. We also address context modeling for efficient entropy coding within the SPIHT framework. Both lossy and lossless coding performance are better than those previously reported.

This paper presents a dynamically adaptive stabilization scheme for parallel matrix computation. The scheme performs automatic error detection and correction through inserting redundant, but concurrent tracer computations within the folds of the regular computation. It also eliminates the costly row interchange used in classical pivoting. A fault-tolerant double wavefront matrix algorithmfor a MIMD array multi-processor with toroidal inter connection has been designed to demonstrate the strength of the proposed scheme. This algorithm can compute: i) matrix inverse ii) solution vector to the linear system and Hi) predetermined linear combination of the solution vector from identical algorithmic framework. This efficient tri-solution algorithm excels most other known methods in parallel performance.

A hierarchical neural network approach is presented for the automatic conversion of image documents (ACID), which specifically describes a prototype symbol recognition system (SRS) for automatic computer processing of electrical engineering drawings. This approach achieves a significant reduction of human involvement in the symbol model encoding and recognition processes in contrast to such traditional approaches based on thinning, line tracing, and other structural feature extraction techniques. A set of image intensity moments, which are invariant to geometric transformations, is used as features. A hierarchical neural classifier demonstrates faster and more accurate capabilities for model encoding and recognition. The test results from hand-drawn images by using templates achieves a recognition rate of 98.5% on training symbols and 89% on test symbols.>

The authors present an animation tool for visualizing the complex, dynamic behavior of parallel algorithms. The key idea behind this tool design is to abstract run-time activities and turn them into graphical representations that move and vary in location, size, and color. With proper abstractions, it establishes a technical foundation for monitoring, analyzing, and improving complex parallel algorithms. It represents animated views in an informative and coherent manner. There are two unique attributes that distinguish the animation tool from others: (1) it provides a general simulation environment for analyzing parallel algorithms with arbitrary program structures and sizes; and (2) it allows the visualization for computation status of parallel processes and their run-time interactions.>

We present a novel approach for automating the functional design of digital systems. Given a set of behavioral specifications, the objective is to produce an optimal functional design which minimizes certain design criteria. One distinct feature of this approach is adding the step of function minimization. That is, the abstraction of the primitive operations into a set of functions that generates the desired behavior attempts to minimize the cost of that set according to the design criteria. For this purpose, it is important to have a powerful search strategy which will lead to a near-optimal solution in a reasonable time. We have adopted best-first search (A* algorithm) as the general framework, and developed several domain-specific heuristic functions (h') which control the search process. Preliminary experimental results are reported.

The problem of residue, or modular, arithmetic is fundamental to symbolic and algebraic computation, coding theory and applications, as well as to error-free arithmetic computations. This paper describes novel algorithms that can lead to efficient hardware for arithmetic operations in residue domains. One of the main achievements is in allowing the flexibility of changing moduli. The technology of systolic array has been used to implement one of the most representative operations, the modular multipler. It is shown that a linear systolic array can compute N modular products in time O(N) with constant number of cells.

An expert system known as CMS-HELP has been developed to serve as an on-line consultant to users of the VM/CMS opening system. It assists computer users (novice or experienced), who attempt to use unfamiliar system facilities, by giving prompt advice of a sequence of commands to accomplish a desired user task. The domain for CMS-HELP is the collection of CMS command modules and EXEC's at IBM Research. This set of command facilities is treated as data by the expert system. The source of knowledge is mainly provided by the command descriptions and system consultants, who are expert users of these commands. This expert system exemplifies data/knowledge engineering to develop an intelligent agent capable of providing on-line consultation. Thereby, the system serves important functions to both the developers and the users of CMS commands: it makes the programs more usable and understandable and it makes the users more productive and receptive. Thus, the system brings data/knowledge and its users closer together.

In this paper the problem of computing the Discrete Fourier Transform (DFT) in VLSI is considered. We describe an approach to extend the linear systolic array algorithm to the multidimensional systolic network algorithm. The proposed networks is based on the pipeline design and have regular structure. Among them the mesh-connected network matches, with a small factor, the known theoretical Ω(n2) lower bound to the (area × time2) measure of complexity in the planar VLSI.

The computation of residues with respect to a set of given moduli and the Chinese remainder algorithm can be considered a pair of general invertible algebraic mappings. This class of algebraic mappings include the more familiar mappings of evaluation and interpolation as well as forward and inverse fast Fourier transform (FFT). The utility and significance of these mappings are fully recognized in such fields as symbolic and algebraic computation and signal processing. The importance of the more general pair of mappings as algebraic techniques is just beginning to be appreciated. All these mapping techniques are presented in this paper from a unifying perspective. Then, a uniform upper bound for these pairs of invertible mappings in terms of computational cost or time is established. Hopefully, this effort alleviates concerns of applicability of these mapping techniques and encourages their use in numerous other potential application areas.