name stringlengths 5 6 | title stringlengths 8 144 | abstract stringlengths 0 2.68k | fulltext stringlengths 1.78k 95k | keywords stringlengths 22 532 |
|---|---|---|---|---|
611453 | The Chebyshev iteration revisited. | Compared to Krylov space methods based on orthogonal or oblique projection, the Chebyshev iteration does not require inner products and is therefore particularly suited for massively parallel computers with high communication cost. Here, six different algorithms that implement this method are presented and compared wit... | Introduction
The Chebyshev iteration [2{4] has been one of the favorite Krylov space methods
for solving a large sparse linear system of equations in a parallel environ-
ment, since, unlike methods based on orthogonalization (such as the conjugate
gradient (CG) and biconjugate gradient (BiCG) methods and GMRes|to
name ... | coupled two-term recurrences;chebyshev iteration;second-order Richardson iteration;sparse linear systems;roundoff error analysis |
613633 | Scalable Human-Friendly Resource Names. | Currently, Uniform Resource Locators (URLs) are used to name and access Web-based resources. However, URLs pose a significant scalability problem because they cannot be used to refer to replicated Web pages. The authors propose a new URI scheme called Human-Friendly Names (HFNs) to solve this scalability problem. HFNs ... | Introduction
Resources in the World Wide Web are named using Uniform Resource Identifiers
(URIs). The most common and well-known type of URI is the Uniform Resource
Locator (URL). A URL is used in the Web for two distinct purposes: to identify
resources and to access resources. Unfortunately, combining these two leads ... | DNS;scalability;resource location;wide-area systems;keywords: naming |
613982 | Assessing the Performance of the New IBM SP2 Communication Subsystem. | IBM has recently launched an upgrade of the communication subsystem of its SP2 parallel computer. This change affects both hardware and software elements: high-performance switch, message interface adapters, and a new implementation of the MPI message-passing library. To characterize to what extent these changes will a... | Introduction
A long time has passed since the high-performance computing community realized that
the highest computation speeds at reasonable cost can only be reached via massive
parallelism. During the eighties and early nineties a sort of "building euphoria" led to the
* This work has been done while R. Beivide and J... | massively parallel computers;message-passing network;performance evaluation;IBM SP2;communication subsystem |
614294 | Visualization of Multidimensional Shape and Texture Features in Laser Range Data Using Complex-Valued Gabor Wavelets. | AbstractThis paper describes a new method for visualization and analysis of multivariate laser range data using complex-valued non-orthogonal Gabor wavelets, principal component analysis and a topological mapping network. The initial data set that provides both shape and texture information is encoded in terms of both ... | Introduction
One of the major challenges of vision research was, and still is, to develop methods for the automatic
modeling of complex geometric objects or scenes. In spite of countless efforts during the
last decades [2], [42], [32], [36] there is not yet a generic solution to this problem. Electronic
photogrammetry,... | gabor wavelets;wavelet transform;shape;feature extraction;subspace mapping;principal components;and texture analysis;multidimensional visualization;feature-based visualization |
614303 | A Predictor-Corrector Technique for Visualizing Unsteady Flow. | AbstractWe present a method for visualizing unsteady flow by displaying its vortices. The vortices are identified by using a vorticity-predictor pressure-corrector scheme that follows vortex cores. The cross-sections of a vortex at each point along the core can be represented by a Fourier series. A vortex can be faithf... | Introduction
In order to study the complex behavior of an unsteady (i.e., time-varying) fluid flow, one
might imagine being immersed within the flow but not disturbing it. One could then roam
about the flow field, free to observe its development or to measure quantities of interest. This
scenario is impossible in real ... | vortex identification;data reduction;vortex visualization;feature extraction;numerical flow animation;vortex core;numerical flow visualization |
614304 | Quaternion Frame Approach to Streamline Visualization. | AbstractCurves in space are difficult to perceive and analyze, especially when they form dense sets as in typical 3D flow and volume deformation applications. We propose a technique that exposes essential properties of space curves by attaching an appropriate moving coordinate frame to each point, reexpressing that mov... | Introduction
We introduce techniques and tools for visualizing
streamline data that are based on the differential
geometry of 3D space curves. Intrinsic
properties of space curves give rise to scalar fields
over the curves such as the curvature and torsion.
A moving coordinate frame on a curve is a tensor
field that is... | frenet frame;quaternion;orientation frame |
614306 | Visualization of Geometric Algorithms. | AbstractThis paper investigates the visualization of geometric algorithms. We discuss how limiting the domain makes it possible to create a system that enables others to use it easily. Knowledge about the domain can be very helpful in building a system which automates large parts of the users task. A system can be desi... | Introduction
The visualization of mathematical concepts goes
back to the early days of graphics hardware [21],
[2], and continues to the present [18], [16], [15],
[19]. These videos use graphics and motion to
explain geometric ideas in three dimensions and
higher. They have been widely accepted as the
necessary compani... | algorithm animation;three-dimensional geometric algorithms;computational geometry |
614325 | Volume-Preserving Free-Form Solids. | AbstractSome important trends in geometric modeling are the reliance on solid models rather than surface-based models and the enhancement of the expressive power of models, by using free-form objects in addition to the usual geometric primitives and by incorporating physical principles. An additional trend is the empha... | Introduction
Modern geometric modeling emphasizes solid
models rather than surface-based models, usage
of free-form objects in addition to the usual geometric
primitives, incorporation of physical prin-
ciples, and interactive performance. In this paper
we integrate these four issues in a single setting
by endowing the... | continuity constraints;volume preservation;uzawa's algorithm;free-form deformations FFD;physics-based modeling;energy constraints;free-form solids |
614330 | A Near Optimal Isosurface Extraction Algorithm Using the Span Space. | AbstractWe present the "Near Optimal IsoSurface Extraction" (NOISE) algorithm for rapidly extracting isosurfaces from structured and unstructured grids. Using the span space, a new representation of the underlying domain, we develop n isosurface extraction algorithm with a worst case complexity of $O\left ({\sqrt n} k\... | Introduction
Isosurface extraction is a powerful tool for investigating
scalar fields within volumetric data sets. The position of
an isosurface, as well as its relation to other neighboring
isosurfaces, can provide clues to the underlying structure
of the scalar field. In medical imaging applications, isosurfaces
perm... | unstructured grids;isosurface extraction;span space;kd-trees |
614335 | Interactive Time-Dependent Particle Tracing Using Tetrahedral Decomposition. | AbstractStreak lines and particle traces are effective visualization techniques for studying unsteady fluid flows. For real-time applications, accuracy is often sacrificed to achieve interactive frame rates. Physical space particle tracing algorithms produce the most accurate results although they are usually too expen... | INTRODUCTION
Unsteady particle tracing is a relatively new visualization technique that has emerged because of
the need to visualize unsteady or time-dependent data sets. Steady-state flow simulations only
require one set of grid and solution data to describe a flow, while unsteady flow simulations may
comprise of hund... | streak line;particle tracing;tetrahedral decomposition;unsteady flow;scientific visualization;computational fluid dynamics;time-dependent;curvilinear grid |
614347 | A Real-Time Photo-Realistic Visual Flythrough. | AbstractIn this paper we present a comprehensive flythrough system which generates photo-realistic images in true real-time. The high performance is due to an innovative rendering algorithm based on a discrete ray casting approach, accelerated by ray coherence and multiresolution traversal. The terrain as well as the 3... | Introduction
The quest for real-time photo-realistic rendering has been one of the major
goals of 3D computer graphics in recent years. Techniques for adding realism
to the image, such as shading, shadow, textures, and transparency have
been developed. The generation of realistic images in real-time is currently
being ... | parallel rendering;terrain visualization;flight simulator;visual simulations;voxel-based modeling;ray casting |
614361 | Animation of Deformable Models Using Implicit Surfaces. | AbstractThis paper presents a general approach for designing and animating complex deformable models with implicit surfaces. Implicit surfaces are introduced as an extra layer coating any kind of structure that moves and deforms over time. Offering a compact definition of a smooth surface around an object, they provide... | Introduction
In traditional animation systems based on key-framing,
specifying the motion and the successive shapes of objects
interacting with a simulated world, requires a great amount
of specialized knowledge and intuition from the animator.
Models based on simplified physical laws have been proposed
for automating ... | inelasticity;animation;implicit surfaces;collision detection;collision response;deformable models |
614370 | The Lazy Sweep Ray Casting Algorithm for Rendering Irregular Grids. | AbstractLazy Sweep Ray Casting is a fast algorithm for rendering general irregular grids. It is based on the sweep-plane paradigm, and it is able to accelerate ray casting for rendering irregular grids, including disconnected and nonconvex (even with holes) unstructured irregular grids with a rendering cost that decrea... | Introduction
For the visualization of three-dimensional data, whether scalar or vector, direct volume rendering
has emerged as a leading, and often preferred, method. While surface rendering method can be
Partially supported by Sandia National Labs, and by the National Science Foundation (NSF), grant CDA-9626370.
Part ... | ray tracing;computational geometry;scientific visualization;irregular grids;volumetric data;volume rendering;sweep algorithms |
614371 | Speeding Up Isosurface Extraction Using Interval Trees. | AbstractThe interval tree is an optimally efficient search structure proposed by Edelsbrunner [5] to retrieve intervals on the real line that contain a given query value. We propose the application of such a data structure to the fast location of cells intersected by an isosurface in a volume dataset. The resulting sea... | Introduction
A scalar volume dataset is a pair (V; W ), ng is a finite set
of points spanning a
ng is a corresponding
set of values of a scalar field f(x; z), sampled at the points of V , i.e., w
mesh \Sigma
subdividing\Omega into polyhedral cells having their vertices at the points of V is also
given (or computed from... | marching cubes;isosurface extraction;volume visualization;interval tree |
614386 | Multiresolution Representation and Visualization of Volume Data. | AbstractA system to represent and visualize scalar volume data at multiple resolution is presented. The system is built on a multiresolution model based on tetrahedral meshes with scattered vertices that can be obtained from any initial dataset. The model is built off-line through data simplification techniques, and st... | Introduction
Volume datasets used in current applications have different characteristics, but a common problem: a
portant with curvilinear and irregular datasets, where the mesh topology must be stored explicitly for
visualization purposes [40]. Therefore, in some cases interactive image generation from very large data... | multiresolution representation;volume data visualization;tetrahedral meshes |
614387 | Out-of-Core Streamline Visualization on Large Unstructured Meshes. | AbstractThis paper presents an out-of-core approach for interactive streamline construction on large unstructured tetrahedral meshes containing millions of elements. The out-of-core algorithm uses an octree to partition and restructure the raw data into subsets stored into disk files for fast data retrieval. A memory m... | Introduction
Most visualization software tools have been designed for data that can fit into the main memory
of a single workstation. For many scientific applications, data at the desirable accuracy
overwhelm the memory capacity of the scientist's desk-top workstation. This is particularly
true for data obtained from t... | interactive techniques;streamline visualization;disk management;computational fluid dynamics;memory management;out-of-core algorithms;unstructured meshes |
614396 | A New Line Integral Convolution Algorithm for Visualizing Time-Varying Flow Fields. | AbstractNew challenges on vector field visualization emerge as time-dependent numerical simulations become ubiquitous in the field of computational fluid dynamics (CFD). To visualize data generated from these simulations, traditional techniques, such as displaying particle traces, can only reveal flow phenomena in pres... | Introduction
Vector field data arise from computer simulations in a variety of disciplines such as computational
fluid dynamics (CFD), global climate modeling, and electromagnetism. Visualizing these vector
data effectively is a challenging problem due to the difficulties in finding suitable graphical icons
to represen... | flow visualization;flow animation;unsteady flows;line integral convolution;image convolution;parallel algorithm;texture synthesis;vector field visualization |
614405 | Dynamic Catmull-Clark Subdivision Surfaces. | AbstractRecursive subdivision schemes have been extensively used in computer graphics, computer-aided geometric design, and scientific visualization for modeling smooth surfaces of arbitrary topology. Recursive subdivision generates a visually pleasing smooth surface in the limit from an initial user-specified polygona... | INTRODUCTION
Generating smooth surfaces of arbitrary topology is a grand challenge in geometric modeling, computer
graphics and visualization. The recursive subdivision scheme first introduced by Chaikin [1] is very well
suited for this purpose. During the past two decades, a wide variety of subdivision schemes for mod... | finite elements;subdivision surfaces;interactive techniques;computer graphics;visualization;dynamics;CAGD;deformable models |
614463 | Accessibility Analysis Using Computer Graphics Hardware. | AbstractAnalyzing the accessibility of an object's surface to probes or tools is important for many planning and programming tasks that involve spatial reasoning and arise in robotics and automation. This paper presents novel and efficient algorithms for computing accessible directions for tactile probes used in 3D dig... | Introduction
Reasoning about space is crucial for planning and programming of tasks
executed by robots and other computer-controlled machinery. Accessibility
analysis is a spatial reasoning activity that seeks to determine the directions
along which a tool or probe can contact a given portion of a solid object's
surfac... | rasterizing computer graphics hardware;visibility;spatial reasoning;direction cones;visual inspection;dimensional inspection planning;configuration space;accessibility analysis;CAD/CAM;coordinate measuring machines |
614468 | Interactive Virtual Relighting of Real Scenes. | AbstractComputer augmented reality (CAR) is a rapidly emerging field which enables users to mix real and virtual worlds. Our goal is to provide interactive tools to perform common illumination, i.e., light interactions between real and virtual objects, including shadows and relighting (real and virtual light source mod... | For a lighting designer, this system provides realistic
tools to experiment with the illumination of an enhanced
real environment. All that is required is a few photographs
of the real scene, the reconstruction of a small number of
objects, and the system preprocess as will be described in
this paper; the designer can ... | computer augmented reality;virtual relighting;interactivity;common illumination;hierarchical radiosity;global illumination |
615161 | Concurrency control issues in nested transactions. | The concept of nested transactions offers more decomposable execution units and finer-grained control over concurrency and recovery than "flat" transactions. Furthermore, it supports the decomposition of a "unit of work" into subtasks and their appropriate distribution in a computer system as a prerequisite of intratra... | Introduction
When multiple users access a database simultaneously, their data operations have to be coordinated in
order to prevent incorrect results and to preserve the consistency of the shared data. This activity is
called concurrency control and should provide each concurrent user with the illusion that he is refer... | locking;object hierarchies;concurrency control;nested transactions |
618430 | Animals with Anatomy. | Applying anatomical and physiological principles to model and animate animals achieves greater realism. Underlying components represent bones, muscles, and soft tissue; for speed and simplicity, we can model these from ellipsoids. Muscles stretch across joints, and their orientations, sizes, and shapes change during jo... | Introduction
Animals are beautiful, varied, and common, and we would like to see more, and more realistic, ones in
computer-generated images and animations. In general, computer graphics achieves greater realism by developing
methods that simulate the real world, rather than using adhoc methods that just appear somewha... | computer animation;computer modeling;computer graphics;animal and skin modeling |
620236 | Implications of Classical Scheduling Results for Real-Time Systems. | Important classical scheduling theory results for real-time computing are identified. Implications of these results from the perspective of a real-time systems designer are discussed. Uni- processor and multiprocessor results are addressed as well as important issues such as future release times, precedence constraints... | Introduction
Every real-time systems designer should be familiar with a set of important classical scheduling
theory results, i.e., those results largely taken from the literature in complexity theory and
operations research. While knowledge of these results rarely provides a direct solution for
the designer, the impli... | scheduling theory;multiprocessor scheduling;uniprocessor scheduling;real-time |
623900 | Low-Latency Communication Over ATM Networks Using Active Messages. | Recent developments in communication architectures for parallel machines have reduced the communication overheads and latencies by over an order of magnitude. This paper examines whether these techniques can carry over to clusters of workstations connected by an ATM network even though clusters use standard operating s... | Introduction
The shift from slow broadcast-based local area networks
to high bandwidth switched network architectures is
making the use of clusters of workstations 1 as platforms
for parallel processing more and more attractive. While
a number of software packages [5,6] already support
1. The term cluster is used here ... | message passing;communication performance;communication layer;network of workstations;parallel computing |
623929 | A Constant-Time Parallel Sorting Algorithm and Its Optical Implementation. | Sorting is a fundamental operation that has important implications in a vast number of areas. For instance, sorting is heavily utilized in applications such as database machines, where hashing techniques are used to accelerate data processing algorithms. It is also the basis for interprocessor message routing and has s... | Introduction
Sorting is a basic, fundamental operation used for many symbolic, numeric, and artificial intelligence
(AI) tasks. Some of the applications of sorting include the "togetherness" problem,
i.e., the problem of bringing all identical items in a list or file together. Sorting can also be
used for matching prob... | optical computing;parallel processing;parallel sorting;sorting |
624159 | Virtual Network Transport Protocols for Myrinet. | This article describes a protocol for a general-purpose cluster communication system that supports multiprogramming with virtual networks, direct and protected network access, reliable message delivery using message time-outs and retransmissions, a powerful return-to-send error model for applications, and automatic net... | Introduction
With microsecond switch latencies, gigabytes per
second of scalable bandwidth, and low transmission
error rates, cluster interconnection networks
such as Myrinet [BCF+95] can provide substantially
more performance than conventional lo-
This research is supported in part by ARPA grant F30602-95-
C-0014, the... | multiprogramming;cluster communications;network transport protocols;Myrinet LAN |
624870 | Assuring Good Style for Object-Oriented Programs. | The language-independent Law of Demeter, which encodes the ideas of encapsulation and modularity in an easy-to-follow form for object-oriented programmers, is presented. The law was developed during the design and implementation of the Demeter system, which provides a high-level interface to class-based, object-oriente... | Introduction
This paper describes the object-oriented programming style rule called The Law of Demeter.
Along with the 'goto-rule' and other programming style rules inherited from the procedural
programming paradigm, many of which still apply, the Law should be part of the programming
knowledge that is considered when ... | modularity;coupling control;object forms;object-oriented programs;law of demeter;structured induction;encapsulation;information restriction;user interfaces;information hiding;object-oriented programming;demeter system;class forms;good style;high-level interface;programming environments;information localization |
624907 | Recognizing Design Decisions in Programs. | The authors present a characterization of design decisions that is based on the analysis of programming constructs. The characterization underlies a framework for documenting and manipulating design information to facilitate maintenance and reuse activities. They identify and describe the following categories of design... | to express solutions to problems, other concerns such as target machine characteristics intrude. The middle
ground between specifications and code is more nebulous. Webster 1 surveys the variety of notations and
graphical representations that have been used. The design process as a whole can be described as repeatedly
... | interleaving;design decisions;reuse activities;design information;encapsulation;composition;specialization;representation;decomposition;generalization;programming constructs;programming;maintenance;software engineering |
626675 | Efficient Instruction Sequencing with Inline Target Insertion. | Inline target insertion, a specific compiler and pipeline implementation method for delayed branches with squashing, is defined. The method is shown to offer two important features not discovered in previous studies. First, branches inserted into branch slots are correctly executed. Second, the execution returns correc... | Introduction
The instruction sequencing mechanism of a processor determines the instructions to be fetched from
the memory system for execution. In the absence of branch instructions, the instruction sequencing
mechanism keeps requesting the next sequential instructions in the linear memory space. In this
This research... | compiler;instruction sequencing;exceptions;interrupts;pipeline;branch slots;pipeline processing;delayed branches;inline target insertion;parallel programming;squashing;program counter;program compilers |
626722 | Finite Precision Error Analysis of Neural Network Hardware Implementations. | Through parallel processing, low precision fixed point hardware can be used to build a very high speed neural network computing engine where the low precision results in a drastic reduction in system cost. The reduced silicon area required to implement a single processing unit is taken advantage of by implementing mult... | Introduction
The high speed desired in the implementation of many neural network algorithms, such as
back-propagation learning in a multilayer perceptron (MLP), may be attained through the
use of finite precision hardware. This finite precision hardware; however, is prone to errors.
A method of theoretically deriving a... | feedforward neural nets;low precision;neural network algorithms;neural network hardware;multilayer perceptron;forward retrieving;silicon area;finite precision computation;neural chips;error analysis;back-propagation learning;parallel processing;system cost |
626771 | Reconfigurability and Reliability of Systolic/Wavefront Arrays. | The authors study fault-tolerant redundant structures for maintaining reliable arrays. In particular, they assume that the desired array (application graph) is embedded in a certain class of regular, bounded-degree graphs called dynamic graphs. The degree of reconfigurability (DR) and DR with distance (DR/sup d/) of a ... | Introduction
Highly parallel pipelined structures such as systolic or wavefront arrays are attractive
architectures for achieving high throughput [9]. Examples of important potential applications
include digital signal processing [11, 2], large-scale scientific computation on
arrays for solving partial differential equ... | systolic arrays;bounded-degree graphs;wavefront arrays;fault tolerant computing;reconfigurable architectures;reconfigurability;finitely reconfigurable;reliable arrays;dynamic graphs;locally reconfigurable;time complexity;lower bound;fault-tolerant redundant structures;application graph;reliability |
626779 | Fault Injection and Dependability Evaluation of Fault-Tolerant Systems. | The authors describe a dependability evaluation method based on fault injection that establishes the link between the experimental evaluation of the fault tolerance process and the fault occurrence process. The main characteristics of a fault injection test sequence aimed at evaluating the coverage of the fault toleran... | Introduction
The evaluation of a fault tolerant system is a complex task that requires the use of different
levels of modeling (axiomatic, empirical and physical models) and related tools [1]. A large
number of studies (e.g., see [2-4]), have shown the prominence of the efficiency of the fault
tolerance algorithms and ... | dependability measures;distributed fault-tolerant architecture;fault injection;dependability evaluation;distributed processing;fault occurrence process;test sequence;Esprit Delta-4 Project;fault-tolerant systems;fault tolerance process;fault tolerant computing |
626781 | Scattering and Gathering Messages in Networks of Processors. | The operations of scattering and gathering in a network of processors involve one processor of the network (P/sub 0/) communicating with all other processors. In scattering, P/sub 0/ sends distinct messages to P/sub 0/. The authors consider networks that are trees of processors. Algorithms for scattering messages from ... | Introduction
1.1 Communication in Parallel Computation
Communication is an essential component of parallel computation. A variety of modes of
communication have been studied within the framework of networks of processors - identical
processing elements (PEs) that communicate by means of an interconnection network. The
... | multiprocessor interconnection networks;queueing mechanisms;trees of processors;message scattering;distributed processing;networks of processors;buffering;messages gathering;noncolliding paths;scheduling;spanning trees |
626788 | A Data Structure for Circular String Analysis and Visualization. | A csdawg for circular strings, which is obtained by making simple modifications to the compact symmetric directed acyclic word graph (csdawg) for linear strings, is proposed. This data structure does not contain extraneous vertices and, consequently, avoids the disadvantages of previous methods. Using this method, algo... | Introduction
The circular string data type is used to represent a number of objects such as circular
genomes, polygons, and closed curves. Research in molecular biology involves the identification
of recurring patterns in data and hypothesizing about their causes and/or effects
[1, 2]. Research in pattern recognition a... | space complexities;data structure;linear strings;computational geometry;visualization;circular string analysis;compact symmetric directed acyclic word graph;time complexity;data structures;data visualisation;object-oriented language;computational complexity;directed graphs |
626842 | Performance Evaluation of Hierarchical Ring-Based Shared Memory Multiprocessors. | Investigates the performance of word-packet, slotted unidirectional ring-based hierarchical direct networks in the context of large-scale shared memory multiprocessors. Slotted unidirectional rings are attractive because their electrical characteristics and simple interfaces allow for fast cycle times and large bandwid... | Introduction
In this paper we study the performance of large-scale, shared-memory multiprocessors that use a
word-packet, ring-based hierarchical network. This class of architectures is of interest for several
reasons. First, by distributing the shared memory among the processor modules, associating caches
with each pr... | shared memory multiprocessors;parallel architectures;hector prototype;performance;hot spots;communication locality;prefetching;slotted unidirectional ring;memory banks;performance evaluation;shared memory systems;large-scale systems;ring-based;large scale parallel systems |
626879 | Computing Display Conflicts in String Visualization. | Strings are used to represent a variety of objects such as DNA sequences, text, and numerical sequences. A model for a system for the visualization and analysis of strings was proposed by D. Mehta and S. Sahni (1992). The problem of display conflicts that arise in this model was identified and methods to overcome it we... | Introduction
The string data type is used to represent a number of objects such as text strings, DNA
or protein sequences in molecular biology, numerical sequences, etc. Research in molecular
biology, text analysis, and interpretation of numerical data involves the identification of
recurring patterns in data and hypot... | DNA sequences;display conflicts;data visualisation;directed graphs;numerical sequences;string visualization |
626911 | Assignment of Task Modules in Hypercube Multicomputers with Component Failures for Communication Efficiency. | The problem of assigning task modules within a hypercube multicomputer with possible link failures is investigated. A concept of indirect optimization is introduced and a function, called communication traffic, is proposed as the objective of optimization. The assignments obtained from optimizing this function are show... | Introduction
While the abundance of nodes in a hypercube multicomputer allows for executing tasks
that require a large number of nodes, inter-node communication is still a major bottleneck
in achieving the overall speedup. To achieve communication efficiency, considerable efforts
have been made to improve routing algor... | hypercube multicomputers;fault-tolerant routing;communication cost;component failures;communication turnaround time;optimization;communication traffic;indirect optimization;task assignment;NP hard problem;link failures;telecommunication traffic;performance measure;communication efficiency;task modules;hypercube network... |
626918 | A Comparison of Trace-Sampling Techniques for Multi-Megabyte Caches. | The paper compares the trace-sampling techniques of set sampling and time sampling. Using the multi-billion reference traces of A. Borg et al. (1990), we apply both techniques to multi-megabyte caches, where sampling is most valuable. We evaluate whether either technique meets a 10% sampling goal: a method meets this g... | Introduction
Computer designers commonly use trace-driven simulation to evaluate alternative CPU caches [SMIT82].
But as cache sizes reach one megabyte and more, traditional trace-driven simulation requires very long traces
(e.g., billions of references) to determine steady-state performance [BOKW90, STON90]. But long ... | consecutive references;memory architecture;relative error;reference traces;time sampling;performance evaluation;multi-megabyte caches;program diagnostics;sampling goal;cold-start bias;trace-sampling techniques;digital simulation;buffer storage |
626956 | Faster Numerical Algorithms Via Exception Handling. | An attractive paradigm for building fast numerical algorithms is the following: 1) try a fast but occasionally unstable algorithm, 2) test the accuracy of the computed answer, and 3) recompute the answer slowly and accurately in the unlikely event it is necessary. This is especially attractive on parallel machines wher... | Introduction
A widely accepted design paradigm for computer hardware is to execute the most common
instructions as quickly as possible, and replace rarer instructions by sequences of more common
ones. In this paper we explore the use of this paradigm in the design of numerical
algorithms. We exploit the fact that there... | exception handling;parallel algorithms;numerical linear algebra;digital arithmetic;parallel machines;fast numerical algorithms;LAPACK library;IEEE floating point arithmetic;convergence of numerical methods;eigenvalues and eigenfunctions;linear algebra;unstable algorithms |
626961 | Distributed Reset. | A reset subsystem is designed that can be embedded in an arbitrary distributed system in order to allow the system processes to reset the system when necessary. Our design is layered, and comprises three main components: a leader election, a spanning tree construction, and a diffusing computation. Each of these compone... | Introduction
We describe in this paper how to "augment" an arbitrary distributed system so that each of
its processes can reset the system to a predefined global state, when deemed necessary. The
augmentation does not introduce new processes or new communication channels to the system.
It merely introduces additional m... | diffusing computation;robustness;fault tolerant computing;process failures;self-stabilizing components;system recovery;distributed reset subsystem;distributed processing;channel failures;process repairs;up-process coordination;leader election;embedded system;layered design;channel repairs;fault tolerance;spanning tree ... |
626974 | Memory Latency Effects in Decoupled Architectures. | Decoupled computer architectures partition the memory access and execute functions in a computer program and achieve high-performance by exploiting the fine-grain parallelism between the two. These architectures make use of an access processor to perform the data fetch ahead of demand by the execute process and hence a... | Introduction
The execution of a computer program involves two interrelated processes - accessing
data elements from memory and the true computations. A large amount of parallelism
exists between these two tasks. The concurrent execution of these tasks can result in high
performance and this is the principle of decouple... | interleaving;decoupled architectures;simulation study;memory access delays;performance evaluation;computer architecture;decoupled systems;fine-grain parallelism;cache based uniprocessors;memory latency effects;performance studies;digital simulation;buffer storage |
626977 | A Time Redundancy Approach to TMR Failures Using Fault-State Likelihoods. | Failure to establish a majority among the processing modules in a triple modular redundant (TMR) system, called a TMR failure, is detected by using two voters and a disagreement detector. Assuming that no more than one module becomes permanently faulty during the execution of a task, Re-execution of the task on the Sam... | Introduction
Fault tolerance is generally accomplished by using redundancy in hardware, software,
time, or combination thereof. There are three basic types of redundancy in hardware and
software: static, dynamic, and hybrid. Static redundancy masks faults by taking a majority
of the results from replicated tasks [13]. ... | bayes methods;voters;time redundancy approach;redundancy;adaptive recovery method;triple modular redundant system;system reconfiguration;processing modules;disagreement detector;fault-state likelihoods;simulation results;bayes theorem;TMR failures;fault tolerant computing;digital simulation |
626980 | Efficient Boolean Manipulation with OBDD''s Can be Extended to FBDD''s. | OBDD's are the state-of-the-art data structure for Boolean function manipulation. Basic tasks of Boolean manipulation such as equivalence test, satisfiability test, tautology test and single Boolean synthesis steps can be performed efficiently in terms of fixed ordered OBDD's. The bottleneck of most OBDD-applications i... | Introduction
The need for data structures for Boolean functions becomes obvious if one has applications
in mind as circuit design, optimization, verification, testing, etc. Let us
consider e.g. basic problems of logic verification. By means of hardware description
languages circuits can be described at a very high leve... | tautology test;data structure;satisfiability test;OBDD;circuit design;total computation;equivalence test;data structures;canonical representations;boolean manipulation;boolean functions;logic design;boolean function manipulation |
627003 | Buffered Banks in Multiprocessor Systems. | AbstractA memory design based on logical banks is analyzed for shared memory multiprocessor systems. In this design, each physical bank is replaced by a logical bank consisting of a fast register and subbanks of slower memory. The subbanks are buffered by input and output queues which substantially reduce the effective... | Introduction
The gap between memory speed and processor
request rate is increasing rapidly in high
performance systems. This gap is due to a
decrease in processor cycle time, the use of
superscalar and other multiple issue mecha-
nisms, the increase in the number of processors
in shared memory systems, and the demands
... | logical memory banks;buffered memories;vector processors;Cray Y-MP;memory conflicts |
627005 | Flexible and Adaptable Buffer Management Techniques for Database Management Systems. | AbstractThe problem of buffer management in database management systems is concerned with the efficient main memory allocation and management for answering database queries. Previous works on buffer allocation are based either exclusively on the availability of buffers at runtime or on the access patterns of queries. I... | Introduction
In relational database management systems, the buffer manager is responsible for all the operations
on buffers, including load control. That is, when buffers become available, the manager needs to
decide whether to activate a query from the waiting queue and how many buffers to allocate to
that query. Figu... | buffer management;performance analysis;relational databases |
627029 | Distributed Memory Compiler Design For Sparse Problems. | AbstractThis paper addresses the issue of compiling concurrent loop nests in the presence of complicated array references and irregularly distributed arrays. Arrays accessed within loops may contain accesses that make it impossible to precisely determine the reference pattern at compile time. This paper proposes a run ... | Introduction
On modern scalable multicomputers it is widely recognized that, in addition to detecting
and exploiting available parallelism, reducing communication costs is crucial in achieving
good performance. Existing systems such as DINO [34], Fortran D [12], Superb [44],
and communication optimizations only in the ... | compiler;data parallel language;distributed memory;irregular problems;parallel computing |
627083 | Characterizing the Performance of Algorithms for Lock-Free Objects. | AbstractConcurrent access to shared data objects must be regulated by a concurrency control protocol to ensure correctness. Many concurrency control protocols require that a process set a lock on the data it accesses. Recently, there has been considerable interest in lock-free concurrency control algorithms. Lock-free ... | Introduction
Processes (or tasks, threads, etc.) in a concurrent system often access shared objects to coordinate their
activities, whether performing a user computation or maintaining system resources. We regard a shared
object to be a shared data structure and a set of operations on the data structure (in this paper ... | performance modeling;parallel processing;nonblocking;lock-free;synchronization |
627095 | Zero-Aliasing for Modeled Faults. | AbstractWhen using built-in self-test (BIST) for testing VLSI circuits the circuit response to an input test sequence, which may consist of thousands to millions of bits, is compacted into a signature which consists of only tens of bits. Usually a linear feedback shift register (LFSR) is used for response compaction vi... | Introduction
Built-In Self-Test (BIST) is the capability of a circuit to test itself. The idea behind BIST is to
create pattern generators (PGs) to generate test patterns for the circuit and response analyzers
(RAs) to compact the circuit response to the inputs that are applied. The circuit response,
which may consist ... | built-in self-test;linear feedback shift registers;response compaction;zero-aliasing;signature analysis |
627097 | An Algorithm for Exact Bounds on the Time Separation of Events in Concurrent Systems. | AbstractDetermining the time separation of events is a fundamental problem in the analysis, synthesis, and optimization of concurrent systems. Applications range from logic optimization of asynchronous digital circuits to evaluation of execution times of programs for real-time systems. We present an efficient algorithm... | Introduction
In this paper, we derive an exact algorithm that
determines tight upper and lower bounds on the separation
in time of an arbitrary pair of system events.
Depending on the level of abstraction in the specifica-
tion, events may represent low-level signal transitions
at a circuit interface or control flow in... | discrete event systems;asynchronous systems;concurrent systems;time separation of events;abstract algebra;timing verification |
627126 | Edge-Disjoint Spanning Trees on the Star Network with Applications to Fault Tolerance. | AbstractData communication and fault tolerance are important issues in parallel computers in which the processors are interconnected according to a specific topology. One way to achieve fault tolerant interprocessor communication is by exploiting and effectively utilizing the disjoint paths that exist between pairs of ... | Introduction
The star network was proposed in [1] as "an attractive alternative to the n-cube" topology for interconnecting
processors in parallel computers. Since its introduction, the network received considerable attention. Let
us denote by Vn the set of n! permutations of symbols f1; 2; :::; ng. A star interconnect... | communication algorithm;interconnection network;spanning tree;edge-disjoint trees;parallel algorithm;star network;fault tolerance |
627189 | Automatic Accurate Cost-Bound Analysis for High-Level Languages. | This paper describes a language-based approach for automatic and accurate cost-bound analysis. The approach consists of transformations for building cost-bound functions in the presence of partially known input structures, symbolic evaluation of the cost-bound function based on input size parameters, and optimizations ... | Introduction
Analysis of program cost, such as running time and space consumption, is important for
real-time systems, embedded systems, interactive environments, compiler optimizations,
performance evaluation, and many other computer applications. It has been extensively
This work was supported in part by NSF under Gr... | space analysis;worst-case execution time;performance analysis and measurements;timing analysis;cost bound;program optimization;cost analysis;program analysis and transformation;time analysis |
627209 | Design, Implementation, and Performance Evaluation of a Detection-Based Adaptive Block Replacement Scheme. | A new buffer replacement scheme, called DEAR (DEtection-based Adaptive Replacement), is presented for effective caching of disk blocks in the operating system. The proposed DEAR scheme automatically detects block reference patterns of applications and applies different replacement policies to different applications dep... | Introduction
The speed gap between the processor and disks is becoming wider as VLSI technologies advance at
an enormous rate. To overcome this speed gap, buffer caches [1] are used to keep in main memory
This paper was presented in part at the USENIX 1999 Annual Technical Conference and at the Fourth IEEE
Internationa... | performance evaluation;reference pattern;buffer cache;FreeBSD;replacement policy |
627222 | Using Application Benefit for Proactive Resource Allocation in Asynchronous Real-Time Distributed Systems. | This paper presents two proactive resource allocation algorithms, called RBA* and OBA, for asynchronous real-time distributed systems. The algorithms consider an application model where timeliness requirements are expressed using Jensen's benefit functions and propose adaptation functions to describe anticipated applic... | set PR ? p1;p2;p3; .;p . We assume that the clocks of
the processors are synchronized using an algorithm such as
[21]. Furthermore, we use the nonpreemptive version of the
process-scheduling algorithm used at the processors for
scheduling packets at the switch. This is done for system
homogeneity and the consequent sim... | switched real-time Ethernet;asynchronous real-time distributed systems;distributed real-time systems;best-effort resource allocation;benefit functions;best-effort real-time scheduling;proactive resource allocation;adaptive resource allocation |
627258 | Cycle-Time Properties of the Timed Token Medium Access Control Protocol. | AbstractWe investigate the timing properties of the timed token protocol that are necessary to guarantee synchronous message deadlines. A tighter upper bound on the elapse time between the token's lth arrival at any node i and its (l+v)th arrival at any node k is found. A formal proof to this generalized bound is prese... | Introduction
In a distributed system for hard real-time applications, communication through message
exchange between tasks residing on different nodes must happen in bounded time, in order to
guarantee that end-to-end deadline requirements are met. This motivates the use of medium
access control (MAC) communication pro... | timed token medium access control MAC protocol;real-time communications;FDDI networks;protocol timing properties;timed token networks |
627400 | The LDL System Prototype. | The logic data language (LDL) system provides a declarative logic-based language and integrates relational database and logic programming technologies so as to support advanced data and knowledge-based applications. A comprehensive overview of the system and a description of LDL language and the compilation techniques ... | Introduction
The objective of the Logic Data Language (LDL) System is to develop the
technology for a new generation of database systems that support the rapid
development of sophisticated applications-such as expert systems and advanced
scientific and engineering applications. This objective is not new,
since there ha... | knowledge based systems;LDL language;runtime environment;compiled queries;relational database;knowledge-based applications;optimization techniques;high level languages;relational databases;compilation techniques;stored data;target query execution plans;logic programming technologies;logic programming;LDL queries;logic ... |
627416 | A Knowledge-Based Environment for Modeling and Simulating Software Engineering Processes. | The design and representation schemes used in constructing a prototype computational environment for modeling and simulating multiagent software engineering processes are described. This environment is called the articulator. An overview of the articulator's architecture identifying five principal components is provide... | Introduction
Modeling the process of software engineering represents a promising approach toward understanding
and supporting the development of large-scale software systems. The software
process is the collection of related activities, seen as a coherent process subject to reason-
ing, involved in the production of a ... | knowledge based systems;knowledge-based environment;statics;software process behavior simulator;articulator;knowledge base querying mechanism;modelling;prototype computational environment;simulating software engineering processes;design;dynamics;representation schemes;modeling;programming environments;knowledge metamod... |
627506 | Generalization by Neural Networks. | The authors discuss the requirements of learning for generalization, where the traditional methods based on gradient descent have limited success. A stochastic learning algorithm based on simulated annealing in weight space is presented. The authors verify the convergence properties and feasibility of the algorithm. An... | Introduction
Neural networks are being applied to a wide variety of applications from speech generation[1], to handwriting
recognition[2]. Last decade has seen great advances in design of neural networks for a class of problems called
recognition problems, and in design of learning algorithms[3-5, 5-7]. The learning of... | simulated annealing;weight space;learning;convergence properties;learning systems;stochastic learning algorithm;gradient descent;neural networks;neural nets;generalization |
627540 | Incremental Recovery in Main Memory Database Systems. | Recovery activities, like checkpointing and restart, in traditional database management systems are performed in a quiescent state where no transactions are active. This approach impairs the performance of online transaction processing systems, especially when a large volatile memory is used. An incremental scheme for ... | Introduction
The task of a recovery manager in a transaction processing system is to ensure that, despite system and trans-action
failures, the consistency of the database is maintained. To perform this task, book-keeping activities are
performed during the normal operation of the system and restoration activities take... | high-level recovery manager;checkpointing;database management systems;system recovery;updates;storage management;incremental database recovery;page-based incremental restart algorithm;nonvolatile RAM;online transaction processing systems;memory database systems;transaction processing |
627561 | Using Tickets to Enforce the Serializability of Multidatabase Transactions. | To enforce global serializability in a multidatabase environment the multidatabase transaction manager must take into account the indirect (transitive) conflicts between multidatabase transactions caused by local transactions. Such conflicts are difficult to resolve because the behavior or even the existence of local t... | Introduction
M ULTIDATABASE SYSTEM (MDBS) [1], [2] is a facility
that supports global applications accessing
data stored in multiple databases. It is assumed that the
access to these databases is controlled by autonomous and
possibly heterogeneous Local Database Systems (LDBSs).
The MDBS architecture (Figure 1) allows ... | global serializability;local cascadelessness;forced local conflicts;distributed databases;global scheduler;multidatabase transactions;multidatabase transaction manager;local database system;schedules;local strictness;serialization orders;indirect conflicts;data manipulation operations;analogous execution;transaction pr... |
627595 | A System for Approximate Tree Matching. | Ordered, labeled trees are trees in which each node has a label and the left-to-right order of its children (if it has any) is fixed. Such trees have many applications in vision, pattern recognition, molecular biology, programming compilation, and natural language processing. Many of the applications involve comparing ... | Introduction
Ordered, labeled trees are trees in which each node has a label and the left-to-right order of its children (if it has
any) is fixed. 1 Such trees have many applications in vision, molecular biology, programming compilation and
natural language processing, including the representation of images [29], patte... | semantic taxonomy;trees mathematics;molecular biology;approximate-tree-by-example;approximate tree matching;labeled trees;tree data structures;programming compilation;database theory;search problems;pattern recognition;natural language processing;vision;RNA structures;automatic error recovery;dictionary definitions;que... |
627641 | Compiling Conceptual Graphs. | AbstractThis paper addresses problems in conceptual graph implementation: subsumption and classification in a taxonomy. Conceptual graphs are typically stored using a directed acyclic graph data structure based on the partial order over conceptual graphs.We give an improved algorithm for classifying conceptual graphs i... | Introduction
A central element of many natural language processing,
information retrieval, and knowledge based systems is a
large collection of information. This information may be
viewed as a large set of sentences. This paper concentrates
on the problem of answering queries on this set of sentences.
A query is a sent... | associative retrieval;partial orders;conceptual graphs;compilation;hierarchical knowledge bases |
627645 | Structuring Knowledge In Vague Domains. | AbstractIn this paper, we propose a model for structuring knowledge in vague and continuous domains where similarity plays a role in coming up with plausible inferences. The model consists of two levels, one of which is an inference network with nodes representing concepts and links representing rules connecting concep... |
--R
A Connectionist Scheme For Modeling Context
Symbolic Logic and echanical Theorem Proving
The Logic of Plausible Reasoning: A Core Theory
Mundane reasoning by parallel constraint satisfaction
An Introduction to Possibilistic and Fuzzy Logics
Neural Representation of Conceptual Knowledge
Recognition of Semanticall... | knowledge-based systems;vagueness;artificial intelligence;reasoning;knowledge representation;neural networks |
627655 | Chain-Split Evaluation in Deductive Databases. | AbstractMany popularly studied recursions in deductive databases can be compiled into one or a set of highly regular chain generating paths, each of which consists of one or a set of connected predicates. Previous studies on chain-based query evaluation in deductive databases take a chain generating path as an insepara... | Introduction
regular chain forms [8, 9, 21]. Interesting recursive query evaluation techniques [2], such as transitive closure
algorithms [10], magic sets and counting [1], can be applied to the efficient evaluation of compiled chains in
deductive databases. However, it is interesting to observe that some recursions, e... | query optimization;deductive database;recursive query evaluation;query analysis;logic programming;query processing |
627662 | Unified Integration of Explicit Knowledge and Learning by Example in Recurrent Networks. | AbstractWe propose a novel unified approach for integrating explicit knowledge and learning by example in recurrent networks. The explicit knowledge is represented by automaton rules, which are directly injected into the connections of a network. This can be accomplished by using a technique based on linear programming... | Introduction
The resurgence of interest in connectionist models has led several researchers to investigate
their application to the building of "intelligent systems". Unlike symbolic models proposed
in artificial intelligence, learning plays a central role in connectionist models. Many
successful applications have main... | automatic speech recognition;recurrent neural networks;learning automata |
627680 | Implementing Temporal Integrity Constraints Using an Active DBMS. | AbstractThe paper proposes a general architecture for implementing temporal integrity constraints by compiling them into a set of active DBMS rules. The modularity of the design allows easy adaptation to different environments. Both differences in the specification languages and in the target rule systems can be easily... | Introduction
INCE the introduction of databases, the notions of data
consistency and integrity constraints have been playing
an important role in the database application design
process. Integrity constraints can usually be divided into
two categories: static (referring to a static snapshot of the
database) and tempora... | constraint checking;integrity constraints;temporal databases;dynamic constraints |
627693 | Critics for Knowledge-Based Design Systems. | AbstractExpert critics have been built to critique human performance in various areas such as engineering design, decision making, etc. We suggest that critics can also be useful in the building and use of knowledge-based design systems (KBDSs).Knowledge engineers elicit knowledge from domain experts and build a knowle... | Introduction
Engineering design is a domain where a knowledge-based approach has often been adopted
due to the very large number of factors that must be considered and the difficulty in accurately
characterizing them [17]. A brute-force approach is out of the question for configuration
design tasks due to its computati... | knowledge acquisition;design;critiquing;knowledge-based systems |
627698 | A Graph-Based Data Model and its Ramifications. | AbstractCurrently, database researchers are investigating new data models in order to remedy the deficiences of the flat relational model when applied to nonbusiness applications. Herein we concentrate on a recent graph-based data model called the hypernode model. The single underlying data structure of this model is t... | INTRODUCTION
Relational DataBase Management Systems (DBMSs) are currently dominating the commercial
database market-place. The flat relational model (commonly known as the relational model) has
been advocated by Codd since the early 1970's [CODD70]. It has taken about 20 years for the
relational model to attain its pre... | computable update;query and update language;hypernode database;non-well-founded sets;hypernode functional dependency;set-based data model;hypertext;graph-based data model |
627706 | Time-Constrained Query Processing in CASE-DB. | AbstractCASE-DB is a real-time, single-user, relational prototype DBMS that permits the specification of strict time constraints for relational algebra queries. Given a time constrained nonaggregate relational algebra query and a fragment chain for each relation involved in the query, CASE-DB initially obtains a respon... | Introduction
A real-time database has strict, real-time timing constraints in responding to queries. A time-constrained
query is of the form "evaluate the query Q in at most t time units". In a multi-user, real-time DBMS, the
resources (i.e., CPU and data) are shared, and the issue of meeting the time constraint in eva... | query modification;relational databases;databases;real-time databases;query processing |
627715 | A Formal Characterization of Epsilon Serializability. | AbstractEpsilon serializability (ESR) is a generalization of classic serializability (SR). In this paper, we provide a precise characterization of ESR when queries that may view inconsistent data run concurrently with consistent update transactions.Our first goal is to understand the behavior of queries in the presence... | Introduction
Epsilon Serializability (ESR) [21, 29], a generalization of classic serializability (SR), explicitly
allows some limited amount of inconsistency in transaction processing (TP). ESR enhances
concurrency since some non-SR execution schedules are permitted. For example, epsilon-
transactions (ETs) that just p... | concurrency control;epsilon serializability;formal techniques;ACTA;transaction processing |
627724 | A Temporal Access Control Mechanism for Database Systems. | AbstractThis paper presents a discretionary access control model in which authorizations contain temporal intervals of validity. An authorization is automatically revoked when the associated temporal interval expires. The proposed model provides rules for the automatic derivation of new authorizations from those explic... | Introduction
In many real-world situations, permissions have a temporal dimension, in that they are usually limited in time
or may hold only for specific periods of time. In general, however, access control mechanisms provided as part
of commercial data management systems do not have temporal capabilities. In a typical... | access control;temporal reasoning;general logic programs;database security;database management;temporal authorization |
627737 | A Guide to the Literature on Learning Probabilistic Networks from Data. | AbstractThis literature review discusses different methods under the general rubric of learning Bayesian networks from data, and includes some overlapping work on more general probabilistic networks. Connections are drawn between the statistical, neural network, and uncertainty communities, and between the different me... | Introduction
Probabilistic networks or probabilistic graphical models
are a representation of the variables in a problem and
the probabilistic relationships among them. Bayesian net-
works, a popular kind of probabilistic network, have been
used in different applications including fault diagnosis,
medical expert system... | bayesian networks;learning;graphical models;hidden variables;knowledge discovery;learning structure;probabilistic networks |
627752 | Objective-Driven Monitoring for Broadband Networks. | AbstractAn approach to sensor configuration, installation, and activation for real-time monitoring of broadband networks for managing its performance is presented. An objective-driven measurement strategy for establishing the dynamic and statistical databases of the network is described. Objective driven monitoring all... | Introduction
Broadband networks consist of many subsystems (switching nodes, multiplexers, links, etc.) that
are geographically distributed, carry multiple classes of traffic and have access to different information
patterns. Although these subsystems make their own local decisions, they work together
for the achieveme... | sensor;monitoring;knowledge-based systems;quality of service;performance management;network |
627754 | Optimization of Parallel Execution for Multi-Join Queries. | AbstractIn this paper, we study the subject of exploiting interoperator parallelism to optimize the execution of multi-join queries. Specifically, we focus on two major issues: 1) scheduling the execution sequence of multiple joins within a query, and 2) determining the number of processors to be allocated for the exec... | Introduction
There has been a growing interest in applying general purpose parallel machines to database applications
[7, 8, 12, 19, 34, 43, 50]. Several research systems have been developed to explore this
trend, including GAMMA [16], XPRS [49], DBS3 [4], GRACE [31], and BUBBA [6]. Relational
databases have a certain ... | multi-join query;system fragmentation;synchronous execution time;execution dependency;bushy trees |
627765 | A Knowledge-Based Approach for Retrieving Images by Content. | AbstractA knowledge-based approach is introduced for retrieving images by content. It supports the answering of conceptual image queries involving similar-to predicates, spatial semantic operators, and references to conceptual terms. Interested objects in the images are represented by contours segmented from images. Im... | Introduction
Retrieving images by content is a key technology for image databases. Pixel matching methods
employed for content-based retrieval are time-consuming and of limited practical use
since little of the image object semantics is explicitly modeled. QBIC [18] uses global shape
features such as area and circulari... | spatial relationship model;knowledge-based spatial image model;cooperative query processing;shape model;retrieve image by feature and content;spatial query processing;medical Image database;knowledge-based query processing |
627767 | Tries for Approximate String Matching. | AbstractTries offer text searches with costs which are independent of the size of the document being searched, and so are important for large documents requiring spelling checkers, case insensitivity, and limited approximate regular secondary storage. Approximate searches, in which the search pattern differs from the d... | Introduction
The need to find an approximate match to a string arises in many practical
problems. For example, if an optical character reader interprets a "D" as
an "O", an automatic checker would need to look up the resulting word, say
"eoit" in a dictionary to find that "edit" matches it up to one substitution. Or
a ... | approximate matching;text search |
627771 | The Starburst Active Database Rule System. | AbstractThis paper describes our development of the Starburst Rule System, an active database rules facility integrated into the Starburst extensible relational database system at the IBM Almaden Research Center. The Starburst rule language is based on arbitrary database state transitions rather than tuple- or statemen... | Introduction
Active database systems allow users to create rules-rules specify data manipulation operations
to be executed automatically whenever certain events occur or conditions are met.
Active database rules provide a general and powerful mechanism for traditional database features
such as integrity constraint enfo... | expert database systems;extensible database systems;database production rules;active database systems |
627784 | Computation of Stable Models and Its Integration with Logical Query Processing. | AbstractThe well-founded semantics and the stable model semantics capture intuitions of the skeptical and credulous semantics in nonmonotonic reasoning, respectively. They represent the two dominant proposals for the declarative semantics of deductive databases and logic programs. However, neither semantics seems to be... | Introduction
Significant progress has been made in understanding the declarative semantics of deductive
databases and logic programs with negation. Two dominant proposals are the well-founded
semantics [31] and the stable model semantics [13]. For a normal logic program, where the body
of each rule is a conjunction of ... | stable model semantics;alternating fixpoint logic;deductive database;logic programming;logical query evaluation;nonmonotonic reasoning;well-founded semantics |
627792 | Storage Allocation Policies for Time-Dependent Multimedia Data. | AbstractMultimedia computing requires support for heterogeneous data types with differing storage, communication, and delivery requirements. Continuous media data types such as audio and video impose delivery requirements that are not satisfied by conventional physical storage organizations. In this paper, we describe ... | Introduction
Files comprised of multimedia data are different from conventional data files in many re-
spects. As shown in Table 1, multimedia data, and hence files, consume enormous space
and bandwidth relative to program files or "text" documents. For example, a single feature-length
JPEG-compressed movie can require... | performance modeling;multimedia;time-dependent audio and video data;scheduling;physical data organization;file systems;secondary storage |
627797 | Efficient Mining of Association Rules in Distributed Databases. | AbstractMany sequential algorithms have been proposed for mining of association rules. However, very little work has been done in mining association rules in distributed databases. A direct application of sequential algorithms to distributed databases is not effective, because it requires a large amount of communicatio... | Introduction
Database mining has recently attracted tremendous amount of attention in database research because
of its applicability in many areas, including decision support, marketing strategy and financial
forecast. The research community has observed that data mining, together with data warehousing
and data reposit... | distributed data mining;data mining;knowledge discovery;distributed database;association rule;partitioned database;distributed algorithm |
627803 | Parallel Mining of Association Rules. | AbstractWe consider the problem of mining association rules on a shared-nothing multiprocessor. We present three algorithms that explore a spectrum of trade-offs between computation, communication, memory usage, synchronization, and the use of problem-specific information. The best algorithm exhibits near perfect scale... | Introduction
With the availability of inexpensive storage and the progress in data capture technology, many organizations have
created ultra-large databases of business and scientific data, and this trend is expected to grow. A complementary
technology trend is the progress in networking, memory, and processor technolo... | data mining;parallel algorithms;association rules |
627813 | The Role of Polymorphic Reuse Mechanisms in Schema Evolution in an Object-Oriented Database. | AbstractA seamless approach to the incremental design and reuse of object-oriented methods and query specifications is presented. We argue for avoiding or minimizing the effort required for manually reprogramming methods and queries due to schema modifications, and demonstrate how the role of polymorphic reuse mechanis... | Introduction
Schema evolution, in general, is the ability of a database system to respond to the real world requirement
changes by allowing the schema to evolve as seamlessly as possible. Seamless extension of an
The work carried out at the University of Frankfurt was supported partly by the European Committee under ES... | program adaptation;adaptive software specification and development;object-oriented database systems;schema evolution;software reuse;knowledge reasoning |
627818 | Object-Based Semantic Real-Time Concurrency Control with Bounded Imprecision. | AbstractThis paper describes a concurrency control technique for real-time object-oriented databases that supports logical consistency and temporal consistency, as well as bounded imprecision that results from their trade-offs. The concurrency control technique uses a semantic locking mechanism within each object and u... | Introduction
Real-time applications such as air traffic control, autonomous vehicle control, and automated manufacturing
involve large amounts of environmental sensor data. These applications are supported
by real-time database systems (RTDBMS) [1]. In addition to supporting typical logical consistency
requirements, a ... | semantic concurrency control;bounded imprecision;real-time object-oriented databases |
627837 | Reusing Analogous Components. | AbstractUsing formal specifications to represent software components facilitates the determination of reusability because they more precisely characterize the functionality of the software, and the well-defined syntax makes processing amenable to automation. This paper presents an approach, based on formal methods, to ... | Introduction
The major objectives of a reuse system are to classify the reusable components, to retrieve
them from an existing library, and to modify the retrieved components to satisfy the query
specification [1, 2]. In previous investigations, the construction and retrieval processes have been
formally specified and ... | program modification;analogical reasoning;software reuse;formal methods |
627843 | Efficient Bulk-Loading of Gridfiles. | AbstractThis paper considers the problem of bulk-loading large data sets for the gridfile multiattribute indexing technique. We propose a rectilinear partitioning algorithm that heuristically seeks to minimize the size of the gridfile needed to ensure no bucket overflows. Empirical studies on both synthetic data sets a... | Introduction
We are developing a scientific database to support retrieval of subsets of Computational Fluid Dynamics
(CFD) data sets. Retrieval of subsets is required for visualization and data exploration. All of our data
is two or three-dimensional and thus requires multiattribute indexing. We are specifically intere... | gridfile;bulk loading;databases;dynamic programming;multidimensional indexing;rectilinear partitioning |
627846 | Logic as a Query Language. | AbstractResearch in nonmonotonic reasoning has focused largely on the idea of representing knowledge about the world via rules that are generally true but can be defeated. Even if relational databases are nowadays the main tool for storing very large sets of data, the approach of using nonmonotonic AI formalisms as rel... | Introduction
F OR the purpose of Knowledge Representation, non-monotonic
reasoning (NMR henceforth) formalisms
can be used in two dierent ways:
as languages for representing knowledge about the
world, via rules that are generally true but can be de-
feated. Retrieving information from a non-monotonic
knowledge base of ... | expressive power;default logic;relational databases;query languages;nonmonotonic reasoning |
627861 | Establishing the Relevancy of the Bookkeeping Libraries to the Functional Testing of Computer Implementations. | AbstractIn this paper, we address issues related to the definition of "faults," "errors," and "failures" and their separability, and attribution to the different development processes of computing systems. In particular, we deal with historical databases, which presumably contain certain data (i.e., test failure data) ... | Introduction
Functional testing, defined here as the process of evaluating the functions of computer systems and software
products to assure that they meet pre-specified requirements, constitutes an integral and important process
in the development of computer systems and software products. Functional testing, as most ... | software reliability;error prediction models;faults;error data;data accuracy;functional testing;errors |
627878 | Boolean Similarity Measures for Resource Discovery. | AbstractAs the number of Internet servers increases rapidly, it becomes difficult to determine the relevant servers when searching for information. We develop a new method to rank Internet servers for Boolean queries. Our method reduces time and space complexity from exponential to polynomial in the number of Boolean t... | Introduction
Searching for information in the Internet is a considerable
task. Thousands of servers provide different information
over the networks. Determining appropriate servers
for searching is a common problem. For novice users, they
have no idea where to send requests, and experienced users
may miss new servers h... | resource discovery;ranking;boolean query;information retrieval;similarity measure |
627899 | Coherence Approach to Logic Program Revision. | AbstractIn this paper, we present a new approach to the problem of revising extended programs; we base this approach on the coherence theory initially advocated by Gardenfors for belief revision. Our approach resolves contradiction by removing only conflicting information, not the believed source of it, and therefore, ... | Introduction
T HE extension of logic programs with classical negation
significantly increases the expressive power of logic
programs, but also presents new challenges [9]. Among
other things, the contradiction problem brought up by classical
negation has to be addressed.
Unlike normal programs, an extended program with... | logic programming;knowledge representation;nonmonotonic reasoning;belief revision |
627906 | Efficient Data Mining for Path Traversal Patterns. | AbstractIn this paper, we explore a new data mining capability that involves mining path traversal patterns in a distributed information-providing environment where documents or objects are linked together to facilitate interactive access. Our solution procedure consists of two steps. First, we derive an algorithm to c... | Introduction
Due to the increasing use of computing for various applications, the importance of database mining
is growing at a rapid pace recently. Progress in bar-code technology has made it possible for
retail organizations to collect and store massive amounts of sales data. Catalog companies can also
collect sales ... | data mining;performance analysis;distributed information system;World Wide Web;traversal patterns |
627922 | Performance Analysis of Three Text-Join Algorithms. | AbstractWhen a multidatabase system contains textual database systems (i.e., information retrieval systems), queries against the global schema of the multidatabase system may contain a new type of joinsjoins between attributes of textual type. Three algorithms for processing such a type of joins are presented and their... | Introduction
Researches in multidatabase system have been intensified in recent years [4, 5, 9, 13, 12, 16, 19]. In this
paper, we consider a multidatabase system that contains both local systems that manage structured data
(e.g., relational DBSs) and local systems that manage unstructured data (e.g., information retri... | textual database;join algorithm;multidatabase;information retrieval;query processing |
627933 | Declustering and Load-Balancing Methods for Parallelizing Geographic Information Systems. | AbstractDeclustering and load-balancing are important issues in designing a high-performance geographic information system (HPGIS), which is a central component of many interactive applications(such as real-time terrain visualization. The current literature provides efficient methods for declustering spatial point-data... | Introduction
A high performance geographic information system (HPGIS) is a central component of many interactive
applications like real-time terrain visualization, situation assessment, and spatial decision making. The
geographic information system (GIS) often contains large amounts of geometric and feature data (e.g.
... | high performance;geographic information systems;polygon clipping;declustering methods;range query;load-balancing |
627934 | Navigational Accesses in a Temporal Object Model. | AbstractA considerable research effort has been devoted in past years to query languages for temporal data in the context of both the relational and the object-oriented model. Object-oriented databases provide a navigational approach for data access based on object references. In this paper, we investigate the navigati... | Introduction
temporal join
-join time-
join
navigational
Path expressions
implicit joins explicit
joins
dangling
The importance of temporal data management has long been recognized by the database community
and many techniques for modeling and managing temporal data have been introduced [19, 21]. Most
research in tempo... | static analysis and type checking;navigational data accesses;temporal query languages;temporal object-oriented data models |
627971 | Techniques and Systems for Image and Video Retrieval. | AbstractStorage and retrieval of multimedia has become a requirement for many contemporary information systems. These systems need to provide browsing, querying, navigation, and, sometimes, composition capabilities involving various forms of media. In this survey, we review techniques and systems for image and video re... | Introduction
The increasing availability of multimedia information combined with the decreasing storage and processing
costs have changed the requirements on information systems drastically. Today, general purpose
database systems are incorporating support for multimedia storage and retrieval, as well as features
which... | image and video retrieval;content-based retrieval;information retrieval;multimedia databases |
627982 | Generalization and Generalizability Measures. | AbstractIn this paper, we define the generalization problem, summarize various approaches in generalization, identify the credit assignment problem, and present the problem and some solutions in measuring generalizability. We discuss anomalies in the ordering of hypotheses in a subdomain when performance is normalized ... | Introduction
Generalization in psychology is the tendency to respond in the same way to
different but similar stimuli [6]. Such transfer of tendency may be based on
temporal stimuli, spatial cues, or other physical characteristics. Learning, on
the other hand, may be considered as a balance between generalization and d... | VLSI cell placement and routing;subdomains;probability of win;anomalies in generalization;machine learning;credit assignment problem generalization |
628000 | Symbolic Interpretation of Artificial Neural Networks. | AbstractHybrid Intelligent Systems that combine knowledge-based and artificial neural network systems typically have four phases involving domain knowledge representation, mapping of this knowledge into an initial connectionist architecture, network training, and rule extraction, respectively. The final phase is import... | Introduction
Several researchers have investigated the design of hybrid systems that combine expert and connectionist
subsystems [44, 45, 54, 10, 16, 15, 27]. The typical result is a Knowledge Based Neural
Network (KBNN) system with four phases: (i) the rule base representation phase, where initial
domain knowledge is ... | rule evaluation;neural networks;hybrid systems;knowledge refinement;rule extraction |
628007 | Volume Leases for Consistency in Large-Scale Systems. | AbstractThis article introduces volume leases as a mechanism for providing server-driven cache consistency for large-scale, geographically distributed networks. Volume leases retain the good performance, fault tolerance, and server scalability of the semantically weaker client-driven protocols that are now used on the ... | Introduction
To fulfill the promise of an environment in which essentially all human knowledge is available from
a set of servers distributed across wide area networks, the data infrastructure must evolve from
protocols optimized for one application-browsers-to protocols that support a range of more
demanding applicati... | file system;scalable server;lease;cache consistency;fault tolerance;volume |
628018 | The Ant System Applied to the Quadratic Assignment Problem. | AbstractIn recent years, there has been growing interest in algorithms inspired by the observation of natural phenomena to define computational procedures that can solve complex problems. In this article, we describe a distributed heuristic algorithm that was inspired by the observation of the behavior of ant colonies,... | Introduction
The Quadratic Assignment Problem (QAP) of order n consists in looking for the best
allocation of n activities to n locations, where the terms activity and location should be
considered in their most general sense. It was first formulated in (Koopmans and Beckman,
1957) and since then it has been recognized... | evolutionary computation;combinatorial optimization;knowledge pooling;distributed algorithms;ant system;heuristic algorithms;quadratic assignment problem |
628025 | Finding Interesting Patterns Using User Expectations. | AbstractOne of the major problems in the field of knowledge discovery (or data mining) is the interestingness problem. Past research and applications have found that, in practice, it is all too easy to discover a huge number of patterns in a database. Most of these patterns are actually useless or uninteresting to the ... | Introduction
In knowledge discovery, techniques are constantly being developed and improved for
discovering various types of patterns in databases. While these techniques were shown to be
useful in numerous applications, new problems have also emerged. One of the major problems
is that, in practice, it is all too easy ... | pattern ranking;interesting patterns;post-analysis of patterns;knowledge discovery;unexpectedness |
628028 | Automatic Text Categorization and Its Application to Text Retrieval. | AbstractWe develop an automatic text categorization approach and investigate its application to text retrieval. The categorization approach is derived from a combination of a learning paradigm known as instance-based learning and an advanced document retrieval technique known as retrieval feedback. We demonstrate the e... | Introduction
Text categorization has recently become an active research topic in the area of information retrieval. The
objective of text categorization is to assign entries from a set of pre-specified categories to a document.
A document here refers to a piece of text. Categories may be derived from a sparse classific... | text categorization;instance-based learning;automatic classification;text retrieval;query processing |
628030 | Data Consistency in Intermittently Connected Distributed Systems. | AbstractMobile computing introduces a new form of distributed computation in which communication is most often intermittent, low-bandwidth, or expensive, thus providing only weak connectivity. In this paper, we present a replication scheme tailored for such environments. Bounded inconsistency is defined by allowing con... | Introduction
Advances in telecommunications and in the development of portable computers have provided for
wireless communications that permit users to actively participate in distributed computing even
while relocating from one support environment to another. The resulting distributed environment
is subject to restric... | concurrency control;mobile computing;replication;disconnected operation;adaptability;consistency;transaction management |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.