name stringlengths 5 6 | title stringlengths 8 144 | abstract stringlengths 0 2.68k | fulltext stringlengths 1.78k 95k | keywords stringlengths 22 532 |
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334342 | Signed Digit Addition and Related Operations with Threshold Logic. | AbstractAssuming signed digit number representations, we investigate the implementation of some addition related operations assuming linear threshold networks. We measure the depth and size of the networks in terms of linear threshold gates. We show first that a depth-$2$ network with $O(n)$ size, weight, and fan-in co... | Introduction
High performance addition and addition related operations, such as multiplication, play
an important role in the computer based computational paradigm. A major impediment
to improve the speed of arithmetic execution units incorporating addition and addition
related operations is the presence of carry and b... | redundant adders;carry-free addition;computer arithmetic;redundant multipliers;neural networks;threshold logic;signed-digit arithmetic;signed-digit number representation |
334346 | Algebraic Foundations and Broadcasting Algorithms for Wormhole-Routed All-Port Tori. | AbstractThe one-to-all broadcast is the most primary collective communication pattern in a multicomputer network. We consider this problem in a wormhole-routed torus which uses the all-port and dimension-ordered routing model. We derive our routing algorithms based on the concept of span of vector spaces in linear alge... | Introduction
One-to-all broadcast is an essential communication
operator in multicomputer networks, which has many
applications, such as algebraic problems, barrier syn-
chronization, parallel graph and matrix algorithms,
cache coherence in distributed-share-memory systems,
and data re-distribution in HPF. Wormhole rou... | torus;wormhole routing;interconnection network;one-to-all broadcast;parallel processing;collective communication |
334347 | Lower Bounds on Communication Loads and Optimal Placements in Torus Networks. | AbstractFully populated torus-connected networks, where every node has a processor attached, do not scale well since load on edges increases superlinearly with network size under heavy communication, resulting in a degradation in network throughput. In a partially populated network, processors occupy a subset of availa... | Introduction
Meshes and torus based interconnection networks have been utilized extensively in the design
of parallel computers in recent years [5]. This is mainly due to the fact that these
families of networks have topologies which reflect the communication pattern of a wide
An extended abstract was presented in the ... | routing;torus;interconnection network;edge separator;bisection;placement |
334348 | A Minimal Universal Test Set for Self-Test of EXOR-Sum-of-Products Circuits. | AbstractA testable EXOR-Sum-of-Products (ESOP) circuit realization and a simple, universal test set which detects all single stuck-at faults in the internal lines and the primary inputs/outputs of the realization are given. Since ESOP is the most general form of AND-EXOR representations, our realization and test set ar... | INTRODUCTION
The large increase in the complexity of ASICs has led to a
much greater need for circuit testability and Built-In-Self-Test
(BIST) [1]. The testability properties of different forms of two-level
networks have attracted many researchers
[2, 3, 4, 5, 6]. The forms investigated include Positive Polarity
Reed-... | Built-in Self-Test BIST;easily testable combinational networks;test pattern generation;Design for Testing DFT;AND-EXOR realizations;universal test set;reed-muller expressions;self-testable circuits;single stuck-at fault model |
334432 | Fast Approximation Methods for Sales Force Deployment. | Sales force deployment involves the simultaneous resolution of four interrelated subproblems: sales force sizing, salesman location, sales territory alignment, and sales resource allocation. The first subproblem deals with selecting the appropriate number of salesman. The salesman location aspect of the problem involve... | Introduction
In many selling organizations, sales force deployment is a key means by which sales management
can improve profit. In general, sales force deployment is complicated and has attracted
much analytical study. It involves the concurrent resolution of four interrelated subproblems:
sizing the sales force, sales... | marketing models;salesman location;Application/Distribution of Beverages;Sales Force Sizing;Sales Territory Alignment;Sales Resource Allocation |
334735 | Transparent replication for fault tolerance in distributed Ada 95. | In this paper we present the foundations of RAPIDS ("Replicated Ada Partitions In Distributed Systems"), an implementation of the PCS supporting the transparent replication of partitions in distributed Ada 95 using semi-active replication. The inherently non-deterministic executions of multi-tasked partitions are model... | Introduction
Virtual nodes (i.e., partitions in Ada 95) in a distributed
application can be rendered fault-tolerant by replication. A
failure of a replica of a replicated partition can be masked
thanks to the remaining replicas, which ensure that the partition
remains available in spite of the failure.
Despite Ada's st... | fault tolerance;piecewise determinism;distributed systems;semi-active replication;group communication |
334808 | The Martin Boundary of the Young-Fibonacci Lattice. | In this paper we find the Martin boundary for the Young-Fibonacci lattice YF. Along with the lattice of Young diagrams, this is the most interesting example of a differential partially ordered set. The Martin boundary construction provides an explicit Poisson-type integral representation of non-negative harmonic functi... | Introduction
The Young-Fibonacci lattice YF is a fundamental example of a differential partially
ordered set which was introduced by R. Stanley [St1] and S. Fomin [F1]. In many
ways, it is similar to another major example of a differential poset, the Young lattice
Y. Addressing a question posed by Stanley, S. Okada has... | differential poset;okada algebra;harmonic function;non-commutative symmetric function;martin boundary |
335045 | Structural gate decomposition for depth-optimal technology mapping in LUT-based FPGA designs. | In this paper we study structural gate decomposition in general, simple gate networks for depth-optimal technology mapping using K-input Lookup-Tables (K-LUTs). We show that (1) structural gate decomposition in any K-bounded network results in an optimal mapping depth smaller than or equal to that of the original netwo... | Introduction
The field programmable gate arrays (FPGAs) have been widely used in circuit design
implementation and system prototyping for the advantages of short design cycles and low non-recurring
engineering cost. An important class of FPGAs use lookup-tables (LUTs) as the basic logic elements. A
K-input LUT (K-LUT) ... | simplification;technology mapping;delay minimization;system design;decomposition;logic optimization;programmable logic;computer-aided design of VSLI;synthesis;FPGA |
335179 | Affine Structure and Motion from Points, Lines and Conics. | In this paper several new methods for estimating scene structure and camera motion from an image sequence taken by affine cameras are presented. All methods can incorporate both point, line and conic features in a unified manner. The correspondence between features in different images is assumed to be known.Three new t... | Introduction
Reconstruction of a three-dimensional object from
a number of its two-dimensional images is one of
the core problems in computer vision. Both the
structure of the object and the motion of the camera
are assumed to be unknown. Many approaches
have been proposed to this problem and apart
Supported by the ESP... | closure constraints;matching constraints;reconstruction;affine cameras;multiple view tensors;factorization methods |
335180 | Large Occlusion Stereo. | A method for solving the stereo matching problem in the presence of large occlusion is presented. A data structurethe disparity space imageis defined to facilitate the description of the effects of occlusion on the stereo matching process and in particular on dynamic programming (DP) solutions that find matches and occ... | Introduction
Our world is full of occlusion. In any scene, we are
likely to find several, if not several hundred, occlusion
edges. In binocular imagery, we encounter occlusion
times two. Stereo images contain occlusion edges that
are found in monocular views and occluded regions
that are unique to a stereo pair[ 7]. Oc... | occlusion;dynamic-programming stereo;stereo;disparity-space |
335436 | Efficient and cost-effective techniques for browsing and indexing large video databases. | We present in this paper a fully automatic content-based approach to organizing and indexing video data. Our methodology involves three steps: Step 1: We segment each video into shots using a Camera-Tracking technique. This process also extracts the feature vector for each shot, which consists of two statistical varia... | Introduction
With the rapid advances in data compression and
networking technology, video has become an inseparable
part of many important applications such as digital
libraries, distance learning, public information systems,
electronic commerce, movies on demand, just to name
a few. The proliferation of video data has... | video retrieval;video indexing;video similarity model;shot detection;video browsing |
336059 | Information dependencies. | This paper uses the tools of information theory to examine and reason about the information content of the attributes within a relation instance. For two sets of attributes X and Y, an information dependency measure (InD measure) characterizes the uncertainty remaining about the values for the set Y when the values for... | Introduction
That the well-developed discipline of information theory seemed to have so little to say about information
systems is a long-standing conundrum. Attempts to use information theory to "measure"
the information content of a relation are blocked by the inability to accurately characterize the
underlying domai... | multivalued dependency;armstrong's axioms;functional dependency;entropy;information dependency |
336271 | Efficient Interprocedural Array Data-Flow Analysis for Automatic Program Parallelization. | AbstractSince sequential languages such as Fortran and C are more machine-independent than current parallel languages, it is highly desirable to develop powerful parallelization-tools which can generate parallel codes, automatically or semiautomatically, targeting different parallel architectures. Array data-flow analy... | Introduction
Program execution speed has always been a fundamental concern for computation-intensive applications.
To exceed the execution speed provided by the state-of-the-art uniprocessor machines, programs need to
take advantage of parallel computers. Over the past several decades, much effort has been invested in
... | interprocedural analysis;parallelizing compiler;array data-flow analysis;symbolic analysis |
336423 | Analyzing bounding boxes for object intersection. | Heuristics that exploit bouning boxes are common in algorithms for rendering, modeling, and animation. While experience has shown that bounding boxes improve the performance of these algorithms in practice, the previous theoretical analysis has concluded that bounding boxes perform poorly in the worst case. This paper ... | Introduction
Many computer graphics algorithms improve their performance by using bounding
boxes. The bounding box of a geometric object is a simple volume that encloses
the object, forming a conservative approximation to the object. The most common
form is an axis-aligned bounding box, whose extent in each dimension o... | collison detection;bounding boxes;aspect ratio |
336662 | Content-based book recommending using learning for text categorization. | Recommender systems improve access to relevant products and information by making personalized suggestions based on previous examples of a user's likes and dislikes. Most existing recommender systems use collaborative filtering methods that base recommendations on other users' preferences. By contrast,content-based me... | INTRODUCTION
There is a growing interest in recommender systems that suggest
music, films, books, and other products and services to
users based on examples of their likes and dislikes [19, 26,
11]. A number of successful startup companies like Fire-
fly, Net Perceptions, and LikeMinds have formed to provide
recommendi... | recommender systems;text categorization;information filtering;machine learning |
337106 | Hybrid Fault Simulation for Synchronous Sequential Circuits. | We present a fault simulator for synchronous sequential circuits that combines the efficiency of three-valued logic simulation with the exactness of a symbolic approach. The simulator is hybrid in the sense that three different modes of operationthree-valued, symbolic and mixedare supported. We demonstrate how an autom... | Introduction
Simulation is a basic technique applied in many areas of electronic design. As is well known, the
task of simulation at gate level is to determine values (in a given logic) for every lead of the circuit
with respect to a set of primary input assignments. Also in the testing area numerous tools use
simulati... | symbolic simulation;fault simulation;MOT;BDD;SOT |
337198 | Software evolution in componentware using requirements/assurances contracts. | In practice, pure top-down and refinement-based development processes are not sufficient. Usually, an iterative and incremental approach is applied instead. Existing methodologies, however, do not support such evolutionary development processes very well. In this paper, we present the basic concepts of an overall metho... | INTRODUCTION
Most of today's software engineering methodologies are
This paper originates from the research in the project A1
\Methods for Component-Based Software Engineering" at the
chair of Prof. Dr. Manfred Broy, Institut fur Informatik,
Technische Universitat Munchen. A1 is part of \Bayerischer
Forschungsverbund S... | formal methods;contracts;componentware;software evolution;software architecture;description techniques;object-orientation |
337205 | Deriving test plans from architectural descriptions. | INTRODUCTION
In recent years the focus of software engineering is continuosly
moving towards systems of larger dimensions
and complexity. Software production is becoming more
and more involved with distributed applications running
on heterogeneous networks, while emerging technologies
such as commercial o-the-shelf (CO... | labelled transition systems;functional test plans;software achitectures;integration testing | |
337220 | Three approximation techniques for ASTRAL symbolic model checking of infinite state real-time systems. | ASTRAL is a high-level formal specification language for real-time systems. It has structuring mechanisms that allow one to build modularized specifications of complex real-time systems with layering. Based upon the ASTRAL symbolic model checler reported in [13], three approximation techniques to speed-up the model che... | Introduction
ASTRAL is a high-level formal specification language
for real-time systems. It includes structuring mechanisms
that allow one to build modularized specifications
of complex systems with layering [9]. It has been successfully
used to specify a number of interesting real-time
systems [1, 2, 9, 10, 11, 12]. T... | formal methods;ASTRAL;real-time systems;state machines;formal specification and verification;timing requirements;model checking |
337222 | Light-weight context recovery for efficient and accurate program analyses. | To compute accurate information efficiently for programs that use pointer variables, a program analysis must account for the fact that a procedure may access different sets of memory locations when the procedure is invoked under different callsites. This paper presents light-weight context recovery, a technique that ca... | INTRODUCTION
Software development, testing, and maintenance activities
are important but expensive. Thus, researchers
have investigated ways to provide software tools to improve
the e#ciency, and thus reduce the cost, of these
activities. Many of these tools require program analyses
to extract information about the pro... | program analysis;aliasing;slicing |
337257 | Learning functions represented as multiplicity automata. | We study the learnability of multiplicity automata in Angluin's exact learning model, and we investigate its applications. Our starting point is a known theorem from automata theory relating the number of states in a minimal multiplicity automaton for a function to the rank of its Hankel matrix. With this theorem in ha... | Introduction
The exact learning model was introduced by Angluin [5] and since then attracted a lot of
attention. In particular, the following classes were shown to be learnable in this model:
deterministic automata [4], various types of DNF formulae [1, 2, 3, 6, 16, 17, 18, 20, 29,
33] and multi-linear polynomials over... | DNF;learning disjoint;multiplicity automata;computational learning;learning polynomials |
337358 | An inheritance-based technique for building simulation proofs incrementally. | This paper presents a technique for incrementally constructing safety specifications, abstract algorithm descriptions, and simulation proofs showing that algorithms meet their specifications.The technique for building specifications (and algorithms) allows a child specification (or algorithm) to inherit from its parent... | INTRODUCTION
Formal modeling and validation of software systems is
a major challenge, because of their size and complex-
ity. Among the factors that could increase widespread
usage of formal methods is improved cost-effectiveness
and scalability (cf. [20, 22]). Current software engineering
practice addresses problems o... | system modeling/verification;specialization by inheritance;simulation;refinement;interface extension |
337371 | Towards the principled design of software engineering diagrams. | Diagrammatic specification, modelling and programming languages are increasingly prevalent in software engineering and, it is often claimed, provide natural representations which permit of intuitive reasoning. A desirable goal of software engineering is the rigorous justification of such reasoning, yet many formal acco... | INTRODUCTION
Diagrammatic representations - and attempts to formalise
them - are an area of increasing attention
in modern software engineering. Visual specification
and modelling languages, most notably UML [21], and
domain-specific programming languages [15, 24] typically
have a strong diagrammatic flavour; software
... | software diagrams;programmable logic controllers;diagrammatic languages |
337455 | An approach to architectural analysis of product lines. | This paper addresses the issue of how to perform architectural analysis on an existing product line architecture. The con tribution of the paper is to identify and demonstrate a repeatable product line architecture analysis process. The approach defines a good product line architecture in terms of those quality attribu... | INTRODUCTION
A software product line is a collection of systems that
share a managed set of properties that are derived from
a common set of software assets [4]. A product line
approach to software development is attractive to most
organizations due to the focus on reuse of both intellec-
This research was performed wh... | software architecture analysis;software archtecture;product lines;interferometry software |
337790 | A Faster and Simpler Algorithm for Sorting Signed Permutations by Reversals. | We give a quadratic time algorithm for finding the minimum number of reversals needed to sort a signed permutation. Our algorithm is faster than the previous algorithm of Hannenhalli and Pevzner and its faster implementation by Berman and Hannenhalli. The algorithm is conceptually simple and does not require special da... | Introduction
. In this paper we study the problem of sorting signed permutations
by reversals. A signed permutation is a permutation on the
integers each number is also assigned a sign of plus or minus. A
reversal, (i; j), on transforms to
The minimum number of reversals needed to transform one permutation to another... | reversal distance;computational molecular biology;sorting permutations |
338410 | Strategies in Combined Learning via Logic Programs. | We discuss the adoption of a three-valued setting for inductive concept learning. Distinguishing between what is true, what is false and what is unknown can be useful in situations where decisions have to be taken on the basis of scarce, ambiguous, or downright contradictory information. In a three-valued setting, we l... | Introduction
Most work on inductive concept learning considers a two-valued setting. In such a
setting, what is not entailed by the learned theory is considered false, on the basis
of the Closed World Assumption (CWA) [44]. However, in practice, it is more often
the case that we are confident about the truth or falsity... | inductive logic programming;multi-strategy learning;explicit negation;contradiction handling;non-monotonic learning |
338432 | Relations Between Regularization and Diffusion Filtering. | Regularization may be regarded as diffusion filtering with an discretization where one single step is used. Thus, iterated regularization with small regularization parameters approximates a diffusion process. The goal of this paper is to analyse relations between noniterated and iterated regularization and diffusion fi... | Introduction
Image restoration is among other topics such as optic flow, stereo, and shape-from-
shading one of the classical inverse problems in image processing and computer vision
[4]. The inverse problem of image restoration consists in recovering information about
the original image from incomplete or degraded dat... | regularization;image restoration;total variation denoising;diffusion filtering;inverse problems |
338435 | The Topological Structure of Scale-Space Images. | We investigate the deep structure of a scale-space image. The emphasis is on topology, i.e. we concentrate on critical pointspoints with vanishing gradientand top-pointscritical points with degenerate Hessianand monitor their displacements, respectively generic morsifications in scale-space. Relevant parts of catastrop... | Introduction
1.1 Historical Background
A fairly well understood way to endow an image with a topology is to embed it into a one-parameter
family of images known as a "scale-space image". The parameter encodes "scale" or "resolution"
(coarse/fine scale means low/high resolution, respectively).
Among the simplest is the ... | image topology;catastrophe theory;critical points;scale-space;deep structure |
338870 | Timing Analysis for Data and Wrap-Around Fill Caches. | The contributions of this paper are twofold. First, an automatic tool-based approach is described to bound worst-case data cache performance. The approach works on fully optimized code, performs the analysis over the entire control flow of a program, detects and exploits both spatial and temporal locality within data ... | Introduction
Real-time systems rely on the assumption that the worst-case execution time
(WCET) of hard real-time tasks be known to ensure that deadlines of tasks can be
met - otherwise the safety of the controlled system is jeopardized [18, 3]. Static
Compiler
Information
Control Flow
Configurations
I/D-Cache
Interfac... | wrap-around fill cache;worst-case execution time;data cache;timing analysis |
339206 | A Comparison of Graphical Techniques for Asymmetric Decision Problems. | We compare four graphical techniques for representation and solution of asymmetric decision problems-decision trees, influence diagrams, valuation networks, and sequential decision diagrams. We solve a modified version of Covaliu and Oliver's Reactor problem using each of the four techniques. For each technique, we hig... | Introduction
This paper compares four graphical techniques for representing and solving asymmetric decision
problems-traditional decision trees (DTs), Smith, Holtzman and Matheson's (SHM) [1993] influence
diagrams (IDs), Shenoy's [1993b, 1996] valuation networks (VNs), and Covaliu and
Oliver's [1995] sequential decisio... | Asymmetric Decision Problems;decision trees;influence diagrams;Sequential Decision Diagrams;valuation networks |
339211 | Partitioning Customers Into Service Groups. | We explore the issues of when and how to partition arriving customers into service groups that will be served separately, in a first-come first-served manner, by multiserver service systems having a provision for waiting, and how to assign an appropriate number of servers to each group. We assume that customers can be ... | Introduction
In this paper we consider how to design service systems. We assume that it is possible
to initially classify customers according to some attributes. We then consider partitioning
these customer classes into disjoint subsets that will be served separately, each in a first-come
first-served manner. We assume... | resource sharing;multiserver queues;service-system design;queues;Service Systems with Express Lines;service systems |
339353 | A Multigrid Algorithm for the Mortar Finite Element Method. | The objective of this paper is to develop and analyze a multigrid algorithm for the system of equations arising from the mortar finite element discretization of second order elliptic boundary value problems. In order to establish the inf-sup condition for the saddle point formulation and to motivate the subsequent trea... | Introduction
The mortar method as a special domain decomposition methodology appears to be
particularly attractive because different types of discretizations can be employed in
different parts of the domain. It has been analyzed in a series of papers [5, 6, 20]
mainly in connection with second order elliptic boundary v... | saddle point problems;domain decomposition;mortar method;trace spaces |
339364 | A Theory of Single-Viewpoint Catadioptric Image Formation. | Conventional video cameras have limited fields of view which make them restrictive for certain applications in computational vision. A catadioptric sensor uses a combination of lenses and mirrors placed in a carefully arranged configuration to capture a much wider field of view. One important design goal for catadioptr... | Introduction
Many applications in computational vision require that a large field of view is imaged.
Examples include surveillance, teleconferencing, and model acquisition for virtual reality.
A number of other applications, such as ego-motion estimation and tracking, would also
benefit from enhanced fields of view. Un... | panoramic imaging;defocus blur;sensor resolution;omnidirectional imaging;sensor design;image formation |
339377 | Trust Region Algorithms and Timestep Selection. | Unconstrained optimization problems are closely related to systems of ordinary differential equations (ODEs) with gradient structure. In this work, we prove results that apply to both areas. We analyze the convergence properties of a trust region, or Levenberg--Marquardt, algorithm for optimization. The algorithm may a... | Introduction
. This work involves ideas from two areas of numerical anal-
ysis: optimization and the numerical solution of ordinary differential equations
(odes). We begin by pointing out a connection between the underlying mathematical
problems.
Given a smooth function f R, an algorithm for unconstrained optimization
... | steady state;global convergence;superlinear convergence;gradient system;levenberg-marquardt;unconstrained optimization;quadratic convergence |
339427 | An efficient algorithm for finding a path subject to two additive constraints. | One of the key issues in providing end-to-end quality-of-service guarantees in packet networks is how to determine a feasible route that satisfies a set of constraints while simultaneously maintaining high utilization of network resources. In general, finding a path subject to multiple additive constraints (e.g., delay... | Introduction
Integrated network services (e.g., ATM, Intserv, Diffserv) are being designed to provide quality-
of-service (QoS) guarantees for various applications such as audio, video, and data. Many of these
applications have multiple QoS requirements in terms of bandwidth, delay, delay-jitter, loss, etc. One
of the ... | scalable routing;multiple constrained path selection;QoS routing |
339659 | Energy-driven integrated hardware-software optimizations using SimplePower. | With the emergence of a plethora of embedded and portable applications, energy dissipation has joined throughput, area, and accuracy/precision as a major design constraint. Thus, designers must be concerned with both optimizing and estimating the energy consumption of circuits, architectures, and software. Most of the ... | INTRODUCTION
With more than 95% of current microprocessors going into
embedded systems, the need for low power design has become
vital. Even in environments not limited by battery
life, power has become a major constraint due to concerns
about circuit reliability and packaging costs. The increasing
need for low power s... | compiler optimizations;energy optimization and estimation;hardware-software interaction;system energy;energy simulator;low-power architectures |
339891 | Integral Equation Preconditioning for the Solution of Poisson''s Equation on Geometrically Complex Regions. | This paper is concerned with the implementation and investigation of integral equation based solvers as preconditioners for finite difference discretizations of Poisson equations in geometrically complex domains. The target discretizations are those associated with "cut-out" grids. We discuss such grids and also descr... | Introduction
. This paper deals with the creation of effective solvers for the solution
of linear systems of equations arising from the discretization of Poisson's equation
in multiply connected, geometrically complex, domains. The focus is on discretizations
associated with "cut-out" grids (grids which result from exc... | poisson;integral equation;multiply connected;iterative;preconditioning |
339893 | On-the-Fly Model Checking Under Fairness that Exploits Symmetry. | An on-the-fly algorithm for model checking under fairness is presented. The algorithm utilizes symmetry in the program to reduce the state space, and employs novel techniques that make the on-the-fly model checking feasible. The algorithm uses state symmetry and eliminates parallel edges in the reachability graph. Expe... | Introduction
The state explosion problem is one of the major bottlenecks in temporal logic model
checking. Many techniques have been proposed in the literature [6, 5, 9, 8, 13, 11,
12, 16, 17] for combating this problem. Among these, symmetry based techniques
have been proposed in [5, 9, 13]. In these methods the state... | model checking;automata;symmetry reduction;state explosion;verification |
339896 | Galerkin Projection Methods for Solving Multiple Linear Systems. | In this paper, we consider using conjugate gradient (CG) methods for solving multiple linear systems $A^{(i)} where the coefficient matrices $A^{(i)}$ and the right-hand sides $b^{(i)}$ are different in general.\ In particular, we focus on the seed projection method which generates a Krylov subspace from a set of direc... | Introduction
We want to solve, iteratively using Krylov subspace methods, the following linear systems:
A (i) x
where A (i) are real symmetric positive definite matrices of order n, and in general A (i) 6= A (j)
and b (i) 6= b (j) for i 6= j. Unlike for direct methods, if the coefficient matrices and the right-hand
sid... | krylov space;conjugate gradient method;multiple linear systems;galerkin projection |
339901 | A Fast Algorithm for Deblurring Models with Neumann Boundary Conditions. | Blur removal is an important problem in signal and image processing. The blurring matrices obtained by using the zero boundary condition (corresponding to assuming dark background outside the scene) are Toeplitz matrices for one-dimensional problems and block-Toeplitz--Toeplitz-block matrices for two-dimensional cases.... | Introduction
A fundamental issue in signal and image processing is blur removal. The signal or image obtained
from a point source under the blurring process is called the impulse response function or the
point spread function. The observed signal or image g is just the convolution of this blurring
function h with the "... | toeplitz matrix;circulant matrix;boundary conditions;cosine transform;deblurring;hankel matrix |
339903 | Ordering, Anisotropy, and Factored Sparse Approximate Inverses. | We consider ordering techniques to improve the performance of factored sparse approximate inverse preconditioners, concentrating on the AINV technique of M. Benzi and M. T\r{u}ma. Several practical existing unweighted orderings are considered along with a new algorithm, minimum inverse penalty (MIP), that we propose. W... | Introduction
. Consider solving the system of linear equations:
where A is a sparse nn matrix. Depending on the size of A and the nature of the
computing environment an iterative method, with some form of preconditioning to
speed convergence, is a popular choice. Approximate inverse preconditioners, whose
application r... | preconditioner;conjugate gradient-type methods;anisotropy;approximate inverse;ordering methods |
339937 | A Parallel Algorithm for the Reduction to Tridiagonal Form for Eigendecomposition. | One-sided orthogonal transformations which orthogonalize columns of a matrix are related to methods for finding singular values. They have the advantages of lending themselves to parallel and vector implementations and simplifying access to the data by not requiring access to both rows and columns. They can be used to ... | Introduction
Symmetric eigenvalue problems appear in many applications ranging from computational
chemistry to structural engineering. Algorithms for symmetric eigenvalue
problems have been extensively discussed in the literature [11, 9] and implemented
in various software packages (e.g. LAPACK [1]). With the broader i... | one-sided reductions;reduction algorithms;parallel computing |
340195 | Spatial Color Indexing and Applications. | We define a new image feature called the color correlogram and use it for image indexing and comparison. This feature distills the spatial correlation of colors and when computed efficiently, turns out to be both effective and inexpensive for content-based image retrieval. The correlogram is robust in tolerating large ... | Introduction
In recent times, the availability of image and video
resources on the World-Wide Web has increased
tremendously. This has created a demand for effective
and flexible techniques for automatic image
retrieval and video browsing [4, 8, 9, 15, 30, 31, 33,
40]. Users need high-quality image retrieval (IR)
syste... | image indexing;model-based object recognition;spatial correlation;image features;content-based image retrieval |
340331 | Green''s Functions for Multiply Connected Domains via Conformal Mapping. | A method is described for the computation of the Green's function in the complex plane corresponding to a set of K symmetrically placed polygons along the real axis. An important special case is a set of K real intervals. The method is based on a Schwarz-Christoffel conformal map of the part of the upper half-plane e... | Introduction
. Green's functions in the complex plane are basic tools for the
analysis of real and complex polynomial approximations [10,21,24,30,32], which are
of central importance in the fields of digital signal processing [16,17,19] and matrix
iterations [5,6,11,20,28]. The aim of this article is to show that when ... | krylov subspace iteration;chebyshev polynomial;potential theory;conformal mapping;polynomial approximation;schwarz-christoffel formula;digital filter;green's function |
341024 | Bounds on the Extreme Eigenvalues of Real Symmetric Toeplitz Matrices. | We derive upper and lower bounds on the smallest and largest eigenvalues, respectively, of real symmetric Toeplitz matrices. The bounds are first obtained for positive-definite matrices and then extended to the general real symmetric case. They are computed as the roots of rational and polynomial approximations to spec... | Introduction
The study of eigenvalues of Toeplitz matrices continues to be of interest, due to the
occurrence of these matrices in a host of applications (see [4] for a good overview) including
linear prediction, a well-known problem in digital signal processing.
In this work we present improved bounds on the extreme e... | toeplitz matrix;spectral equation;bounds;rational approximation;secular equation;eigenvalues |
341067 | Analysis of Iterative Line Spline Collocation Methods for Elliptic Partial Differential Equations. | In this paper we present the convergence analysis of iterative schemes for solving linear systems resulting from discretizing multidimensional linear second-order elliptic partial differential equations (PDEs) defined in a hyperparallelepiped $\Omega$ and subject to Dirichlet boundary conditions on some faces of $\Omeg... | Introduction
.
We consider the following second order linear elliptic PDE
subject to Dirichlet and/or Neumann boundary conditions
on
of\Omega (2a)
where Bu is u or @u
is a rectangular domain in R k (the space of
real variables) and ff i (! 0), fi i , fl(- 0), f and g are functions of k variables.
If Line Cubic Spline C... | SOR iterative method;collocation methods;elliptic partial differential equations |
342586 | A Class of Highly Scalable Optical Crossbar-Connected Interconnection Networks (SOCNs) for Parallel Computing Systems. | AbstractA class of highly scalable interconnect topologies called the Scalable Optical Crossbar-Connected Interconnection Networks (SOCNs) is proposed. This proposed class of networks combines the use of tunable Vertical Cavity Surface Emitting Lasers (VCSEL's), Wavelength Division Multiplexing (WDM) and a scalable, hi... | as opposed to the L N2 log2Nlinks required for a
standard binary hypercube. This multiplexing greatly
reduces the link complexity of the entire network, reducing
implementation costs proportionately.
4.2 Network Diameter
The diameter of a network is defined as the minimum
distance between the two most distant processo... | multiprocessor interconnection;parallel architectures;scalability;wavelength division multiplexing;crossbars;optical interconnections;networks;hypercubes |
343378 | On Hoare logic and Kleene algebra with tests. | We show that Kleene algebra with tests (KAT) subsumes propositional Hoare logic (PHL). Thus the specialized syntax and deductive apparatus of Hoare logic are inessential and can be replaced by simple equational reasoning. In addition, we show that all relationally valid inference rules are derivable in KAT and that dec... | INTRODUCTION
Hoare logic, introduced by C. A. R. Hoare in 1969 [Hoare 1969], was the first formal
system for the specification and verification of well-structured programs. This
pioneering work initiated the field of program correctness and inspired dozens of
technical articles [Cook 1978; Clarke et al. 1983; Cousot 19... | kleene algebra;hoare logic;dynamic logic;specification;kleene algebra with tests |
343386 | Locality of order-invariant first-order formulas. | A query is local if the decision of whether a tuple in a structure satisfies this query only depends on a small neighborhood of the tuple. We prove that all queries expressible by order-invariant first-order formulas are local. | Introduction
One of the fundamental properties of first-order formulas is their locality, which means
that the decision of whether in a fixed structure a formula holds at some point (or at a
tuple of points) only depends on a small neighborhood of this point (tuple). This result,
proved by Gaifman [5], gives a good int... | logics;first-order logic;ordered structures;locality |
343442 | Statement-Level Communication-Free Partitioning Techniques for Parallelizing Compilers. | This paper addresses the problem of communication-free partition of iteration spaces and data spaces along hyperplanes. To finding more possible communication-free hyperplane partitions, we treat statements within a loop body as separate schedulable units. Instead of using the information about data dependence distance... | Introduction
It has been widely accepted that local memory access is much faster than memory access involving
interprocessor communication on distributed-memory multicomputers. If data and computation
are not properly distributed across processors, it may cause heavy interprocessor communication.
Although the problem o... | hyperplane partition;parallelizing compilers;communication-free;distributed-memory multicomputers;data communication |
343453 | A Low Overhead Logging Scheme for Fast Recovery in Distributed Shared Memory Systems. | This paper presents an efficient, writer-based logging scheme for recoverable distributed shared memory systems, in which logging of a data item is performed by its writer process, instead of every process that accesses the item logging it. Since the writer process maintains the log of data items, volatile storage can ... | Introduction
Distributed shared memory(DSM) systems[15] transform an existing network of workstations to a powerful
shared-memory parallel computer which could deliver superior price/performance ratio. However,
with more workstations engaged in the system and longer execution time, the probability of failures in-
creas... | rollback-recovery;checkpointing;distributed shared memory system;fault tolerant system;message logging |
343503 | Interval routing schemes allow broadcasting with linear message-complexity (extended abstract). | The purpose of compact routing is to provide a labeling of the nodes of a network, and a way to encode the routing tables so that routing can be performed efficiently (e.g., on shortest paths) while keeping the memory-space required to store the routing tables as small as possible. In this paper, we answer a long-stand... | INTRODUCTION
This paper addresses a problem originally formulated by
D. Peleg, and that can be informally summarized as follows:
\Does networks supporting shortest path compact routing
schemes present specic ability in term of distributed com-
putation? E.g., broadcasting, leader-election, etc." This pa-
Part of this w... | broadcasting;distributed computing;compact routing;interval routing |
343530 | Token-Templates and Logic Programs for Intelligent Web Search. | We present a general framework for the information extraction from web pages based on a special wrapper language, called token-templates. By using token-templates in conjunction with logic programs we are able to reason about web page contents, search and collect facts and derive new facts from various web pages. We gi... | Introduction
In the last few years it became appearant that there is an increasing need for more intelligent
World-Wide-Web information systems. The existing information systems are mainly document
search engines, e.g. Alta Vista, Yahoo, Webcrawler, based on indexing techniques
and therefore only provide the web user a... | logic robots;softbots;information extraction;template based wrappers;logic programming;mediators;deductive web databases;theory reasoning |
343534 | Clock synchronization with faults and recoveries (extended abstract). | We present a convergence-function based clock synchronization algorithm, which is simple, efficient and fault-tolerant. The algorithm is tolerant of failures and allows recoveries, as long as less than a third of the processors are faulty 'at the same time'. Arbitrary (Byzantine) faults are tolerated, without requiring... | INTRODUCTION
Accurate and synchronized clocks are extremely useful to
coordinate activities between cooperating processors, and
therefore essential to many distributed algorithms and sys-
tems. Although computers usually contain some hardware-based
clock, most of these are imprecise and have substantial
drift, as highl... | clock synchronization;proactive systems;mobile adversary |
343562 | A New Convergence Proof for Finite Volume Schemes Using the Kinetic Formulation of Conservation Laws. | We give a new convergence proof for finite volume schemes approximating scalar conservation laws. The main ingredients of the proof are the kinetic formulation of scalar conservation laws, a discrete entropy inequality, and the velocity averaging technique. | Introduction
. We consider the Cauchy problem for nonlinear hyperbolic
scalar conservation laws in several space dimensions.
#t
on the slab # := [0, T
for compactly supported initial data
(R d-1 ). We assume the
flux function f in C 1,1
loc (R) and As is well known, solutions of nonlinear
conservation laws may become d... | conservation laws;finite volume scheme;velocity averaging;kinetic formulation;convergence;entropy solutions;discrete entropy inequality |
343587 | Multigrid for the Mortar Finite Element Method. | A multigrid technique for uniformly preconditioning linear systems arising from a mortar finite element discretization of second order elliptic boundary value problems is described and analyzed. These problems are posed on domains partitioned into subdomains, each of which is independently triangulated in a multilevel ... | Introduction
The mortar finite element method is a non-conforming domain decomposition
technique tailored to handle problems posed on domains that are partitioned into
independently triangulated subdomains. The meshes on different subdomains need
not align across subdomain interfaces. The flexibility this technique off... | mortar;multigrid;finite element method;v-cycle;domain decomposition;preconditioning |
344497 | A Theory-Based Representation for Object-Oriented Domain Models. | AbstractFormal software specification has long been touted as a way to increase the quality and reliability of software; however, it remains an intricate, manually intensive activity. An alternative to using formal specifications directly is to translate graphically based, semiformal specifications into formal specific... | INTRODUCTION
As the field of software engineering continues to evolve toward a more traditional engineering dis-
cipline, a concept that is emerging as important to this evolution is the use of formal specifications,
the representation of software requirements by a formal language [1],[2]. Such a representation
has man... | software engineering;domain models;transformation systems;formal methods |
344876 | Interactive control for physically-based animation. | We propose the use of interactive, user-in-the-loop techniques for controlling physically-based animated characters. With a suitably designed interface, the continuous and discrete input actions afforded by a standard mouse and keyboard allow for the creation of a broad range of motions. We apply our techniques to inte... | Introduction
Interactive simulation has a long history in computer graphics, most
notably in flight simulators and driving simulators. More recently,
it has become possible to simulate the motion of articulated human
models at rates approaching real-time. This creates new opportunities
for experimenting with simulated ... | user interfaces;physically based animation |
344985 | Sequential Regularization Methods for Simulating Mechanical Systems with Many Closed Loops. | The numerical simulation problem of large multibody systems has often been treated in two separate stages: (i) the forward dynamics problem for computing system accelerations from given force functions and constraints and (ii) the numerical integration problem for advancing the state in time. For the forward dynamics p... | Introduction
There has been a growing interest in the development of more efficient algorithms for
multibody dynamics simulations. The increase in size and complexity of spacecraft
and robotic systems is one motivation for this development; another is physically-based
modeling in computer graphics. The numerical simula... | robot simulation;stabilization;regularization;constraint singularities;differential-algebraic equations;multibody systems;higher index |
344992 | The Procrustes Problem for Orthogonal Stiefel Matrices. | In this paper we consider the Procrustes problem on the manifold of orthogonal Stiefel matrices. Given matrices ${\cal A}\in {\Bbb R}^{m\times k},$ ${\cal B}\in {\Bbb R}^{m\times p},$ $m\ge p \ge k,$ we seek the minimum of $\|{\cal A}-{\cal B}Q\|^2$ for all matrices $Q\in {\Bbb R}^{p\times k},$ $Q^TQ=I_{k\times k}$. We... | Introduction
We begin by defining the set OSt(p; k) of orthogonal Stiefel matrices:
which is a compact submanifold of dimension
of the manifold
O(p) of all p \Theta p orthogonal matrices which has dimension 1
(trace A T
2 denote the standard Frobenius norm in R m\Thetak .
The Procrustes problem for orthogonal Stiefel m... | stiefel manifolds;projections on ellipsoids;relaxation methods;procrustes problem |
344994 | Inexact Preconditioned Conjugate Gradient Method with Inner-Outer Iteration. | An important variation of preconditioned conjugate gradient algorithms is inexact preconditioner implemented with inner-outer iterations [G. H. Golub and M. L. Overton, Numerical Analysis, Lecture Notes in Math. 912, Springer, Berlin, New York, 1982], where the preconditioner is solved by an inner iteration to a presc... | Introduction
Iterative methods for solving linear systems are usually combined with a preconditioner that can be
easily solved. For some practical problems, however, a natural and efficient choice of preconditioner
may be one that can not be solved easily by a direct method and thus may require an iterative
method (cal... | conjugate gradient method;inexact preconditioner;inner-outer iterations |
344999 | Distributed Schur Complement Techniques for General Sparse Linear Systems. | This paper presents a few preconditioning techniques for solving general sparse linear systems on distributed memory environments. These techniques utilize the Schur complement system for deriving the preconditioning matrix in a number of ways. Two of these preconditioners consist of an approximate solution process for... | Introduction
The successful solution of many "Grand-Challenge" problems in scientific computing depends
largely on the availability of adequate large sparse linear system solvers. In this context, iterative
solution techniques are becoming a mandatory replacement to direct solvers due to their
more moderate computation... | domain decomposition;parallel preconditioning;distributed sparse linear systems;schur complement techniques |
345249 | A Machine Learning Approach to POS Tagging. | We have applied the inductive learning of statistical decision trees and relaxation labeling to the Natural Language Processing (NLP) task of morphosyntactic disambiguation (Part Of Speech Tagging). The learning process is supervised and obtains a language model oriented to resolve POS ambiguities, consisting of a set ... | Introduction
Part of Speech (pos) Tagging is a very basic and well known Natural Language
Processing (nlp) problem which consists of assigning to each word of a text the
proper morphosyntactic tag in its context of appearance. It is very useful for a
number of nlp applications: as a preprocessing step to syntactic pars... | decision trees induction;part of speech tagging;constraint satisfaction;corpus-based and statistical language modeling;relaxation labeling |
345313 | Automated generation of agent behaviour from formal models of interaction. | We illustrate how a formal model of interaction can be employed to generate documentation on how to use an application, in the form of an Animated Agent. The formal model is XDM, an extension of Coloured Petri Nets that enables representing user-adapted interfaces, simulating their behaviour and making pre-empirical us... | INTRODUCTION
The increasing complexity of user interfaces requires specific
methods and tools to design and describe them; an emerging
solution is to employ formal methods for a precise and
unambiguous specification of interaction. Graphical methods are
preferred since they are more easily perceived by users without a
... | user manuals generation;formal models of interaction;animated agents |
345541 | A novel method for the evaluation of Boolean query effectiveness across a wide operational range. | Traditional methods for the system-oriented evaluation of Boolean IR system suffer from validity and reliability problems. Laboratory-based research neglects the searcher and studies suboptimal queries. Research on operational systems fails to make a distinction between searcher performance and system performance. This... | Figure
1. An example of a high recall Oriented
query used by Harter [10] to illustrate the facet
based query planning approach.
(information retrieval OR
online systems OR
AND
trial(1w)error
expert systems OR
artificial intelligence OR
behavior?/DE,ID,TI
fundamental validity problem. Queries exploit the Boolean IR
mod... | structured queries;test collections;evaluation general;testing methodology |
345772 | Making Nondeterminism Unambiguous. | We show that in the context of nonuniform complexity, nondeterministic logarithmic space bounded computation can be made unambiguous. An analogous result holds for the class of problems reducible to context-free languages. In terms of complexity classes, this can be stated as NL/poly | Introduction
In this paper, we combine two very useful algorithmic techniques (the inductive
counting technique of [Imm88, Sze88] and the isolation lemma of [MVV87]) to
give a simple proof that two fundamental concepts in complexity theory coincide
in the context of nonuniform computation.
Unambiguous computation has b... | ULOG;NLOG;nondeterministic space;unambiguous computation;LogCFL |
345773 | A Combinatorial Consistency Lemma with Application to Proving the PCP Theorem. | The current proof of the probabilistically checkable proofs (PCP) theorem (i.e., ${\cal NP}={\cal PCP}(\log,O(1))$) is very complicated. One source of difficulty is the technically involved analysis of low-degree tests. Here, we refer to the difficulty of obtaining strong results regarding low-degree tests; namely, res... | Introduction
The characterization of NP in terms of Probabilistically Checkable Proofs (PCP systems) [AS,
ALMSS], hereafter referred to as the PCP Characterization Theorem, is one of the more fundamental
achievements of complexity theory. Loosely speaking, this theorem states that membership in
any NP-language can be v... | parallelization of probabilistic proof systems;probabilistically checkable proofs PCP;low-degree tests |
345777 | Reducibility and Completeness in Private Computations. | We define the notions of reducibility and completeness in (two-party and multiparty) private computations. Let g be an n-argument function. We say that a function f is reducible to a function g if n honest-but-curious players can compute the function f n-privately, given a black box for g (for which they secretly ... | Introduction
We consider (two party and multi-party) private computations. Quite informally, given an arbitrary n-
argument function f , a t-private protocol should allow n players, each possessing an individual secret input,
to satisfy simultaneously the following two constraints: (1) (Correctness): all players learn ... | reducibility;oblivious-transfer;completeness;private computation |
345785 | Application-Controlled Paging for a Shared Cache. | We propose a provably efficient application-controlled global strategy for organizing a cache of size k shared among P application processes. Each application has access to information about its own future page requests, and by using that local information along with randomization in the context of a global caching alg... | Introduction
Caching is a useful technique for obtaining high performance in these days where the
latency of disk access is relatively high. Today's computers typically have several
application processes running concurrently on them, by means of time sharing and
multiple processors. Some processes have special knowledg... | application-controlled;competitive;online;caching;randomized |
345884 | Minimizing Expected Loss of Hedging in Incomplete and Constrained Markets. | We study the problem of minimizing the expected discounted loss $$ E\left[e^{-\int_0^Tr(u)du}( C- X^{x,\pi}(T))^+\right] $$ when hedging a liability C at time t=T, using an admissible portfolio strategy $\pi(\cdot)$ and starting with initial wealth x. The existence of an optimal solution is established in the context... | Introduction
In a complete financial market which is free of arbitrage opportunities, any sufficiently integrable
random payoff (contingent claim) C, whose value has to be delivered and is known
at time can be hedged perfectly: starting with a large enough initial capital x, an
agent can find a trading strategy - that ... | hedging;incomplete markets;portfolio constraints;expected loss;dynamic measures of risk |
345891 | On the Minimizing Property of a Second Order Dissipative System in Hilbert Spaces. | We study the asymptotic behavior at infinity of solutions of a second order evolution equation with linear damping and convex potential. The differential system is defined in a real Hilbert space. It is proved that if the potential is bounded from below, then the solution trajectories are minimizing for it and conve... | Introduction
. Consider the following dierential system dened in a real
Hilbert space H
where
is dierentiable. It is customary to call this equation non-linear
oscillator with damping. Here, the damping or friction has a linear dependence
on the velocity. This is a particular case of the so called dissipative systems. ... | convexity;linear damping;implicit discretization;asymptotic behavior;iterative-variational algorithm;weak convergence;dissipative system |
345912 | Analysis of a local-area wireless network. | To understand better how users take advantage of wireless networks, we examine a twelve-week trace of a building-wide local-area wireless network. We analyze the network for overall user behavior (when and how intensively people use the network and how much they move around), overall network traffic and load characteri... | INTRODUCTION
More companies and schools are installing wireless networks
to support a growing population of mobile laptop and PDA users.
Part of the motivation for these installations is to reduce the costs
of running cable. Another important motivation is to meet the
demands of users who wish to stay connected to the ... | local-area wireless networks;network analysis |
346037 | Reducing virtual call overheads in a Java VM just-in-time compiler. | Java, an object-oriented language, uses virtual methods to support the extension and reuse of classes. Unfortunately, virtual method calls affect performance and thus require an efficient implementation, especially when just-in-time (JIT) compilation is done. Inline caches and type feedback are solutions used by compil... | Introduction
Java is a recently created object-oriented programming
language [5]. As an object-oriented programming
language, it supports virtual methods, which allow different
code to be executed for objects of dierent types
with the same call.
Virtual method calls in Java incur a performance
penalty because the targe... | Java JIT compilation;type feedback;adaptive compilation;virtual method call;inline cache |
346607 | Symbolic Cache Analysis for Real-Time Systems. | Caches impose a major problem for predicting execution times of real-time systems since the cache behavior depends on the history of previous memory references. Too pessimistic assumptions on cache hits can obtain worst-case execution time estimates that are prohibitive for real-time systems. This paper presents a nove... | Introduction
Due to high-level integration and superscalar architectural designs the
computational capability of microprocessors has increased significantly
in the last few years. Unfortunately the gap between processor cycle
time and memory latency increases. In order to fully exploit the potential
of processors, the ... | worst-case execution time;symbolic evaluation;cache hit prediction;static analysis |
346866 | Analytical comparison of local and end-to-end error recovery in reactive routing protocols for mobile ad hoc networks. | In this paper we investigate the effect of local error recovery vs. end-to-end error recovery in reactive protocols. For this purpose, we analyze and compare the performance of two protocols: the Dynamic Source Routing protocol (DSR[2]), which does end-to-end error recovery when a route fails and the Witness Aided Rout... | Introduction
Routing protocols for ad hoc networks can be classified in two
general categories: reactive and proactive, depending on their
reaction to changes in the network topology. Proactive proto-
cols, such as distance-vector protocols (DSDV[4]), are highly
sensitive to topology changes. They require mobile hosts ... | mobile ad hoc network;performance analysis;routing protocol |
347309 | On the Perturbation Theory for Unitary Eigenvalue Problems. | Some aspects of the perturbation theory for eigenvalues of unitary matrices are considered. Making use of the close relation between unitary and Hermitian eigenvalue problems a Courant--Fischer-type theorem for unitary matrices is derived and an inclusion theorem analogous to the Kahan theorem for Hermitian matrices... | Introduction
. New numerical methods to compute eigenvalues of unitary
matrices have been developed during the last ten years. Unitary QR-type methods
[19, 9], a divide-and-conquer method [20, 21], a bisection method [10], and some special
methods for the real orthogonal eigenvalue problem [1, 2] have been presented.
I... | unitary eigenvalue problem;perturbation theory |
347479 | Speed is as powerful as clairvoyance. | We introduce resource augmentation as a method for analyzing online scheduling problems. In resource augmentation analysis the on-line scheduler is given more resources, say faster processors or more processors, than the adversary. We apply this analysis to two well-known on-line scheduling problems, the classic unipro... | Introduction
We consider several well known nonclairvoyant
scheduling problems, including the problem of minimizing
the average response time [13, 15], and best-effort
firm real-time scheduling [1, 2, 3, 4, 8, 11, 12, 18].
(We postpone formally defining these problems until
the next section.) In nonclairvoyant scheduli... | resource augmentation;multi-level feedback scheduling;scheduling |
347482 | Balanced sequences and optimal routing. | The objective pursued in this paper is two-fold. The first part addresses the following combinatorial problem: is it possible to construct an infinite sequence over n letters where each letter is distributed as evenly as possible and appears with a given rate? The second objective of the paper is to use this constructi... | Introduction
It is a rather general problem to consider a system with multiple resources and tasks. Tasks
can be performed by any resource and arrive in the system sequentially. The problem is to
construct a routing of the tasks to the resources to minimize a given cost function. Such
models are common in multiprocesso... | optimal control;stochastic event graphs;multimodularity;balanced sequences |
347550 | New Methods for Estimating the Distance to Uncontrollability. | Controllability is a fundamental concept in control theory. Given a linear control system, we present new algorithms for estimating its distance to uncontrollability, i.e., the norm of the normwise smallest perturbation that makes the given system uncontrollable. Many algorithms have been previously proposed to estimat... | Introduction
One of the most fundamental concepts in control theory is that of controllability. A matrix pair
n\Thetan \Theta C n\Thetam is controllable (see Kailath [20, pages 85-90]) if the state function
in the linear control system
can be directed from any given state to a desired state in finite time by an input
c... | QR factorization;controllability;complexity;numerical stability |
347551 | On the propagation of long-range dependence in the Internet. | This paper analyzes how TCP congestion control can propagate self-similarity between distant areas of the Internet. This property of TCP is due to its congestion control algorithm, which adapts to self-similar fluctuations on several timescales. The mechanisms and limitations of this propagation are investigated, and i... | INTRODUCTION
Statistical self-similarity and long-range dependence are important
topics of recent research studies. Both phenomena
are related to certain scale-independent statistical proper-
ties. Statistical self-similarity can be detected when trafc
rate
uctuates on several timescales and its distribution
scales wit... | TCP congestion control;long-range dependence;TCP adaptivity;self-similarity |
347556 | Staircase Failures Explained by Orthogonal Versal Forms. | Treating matrices as points in n2-dimensional space, we apply geometry to study and explain algorithms for the numerical determination of the Jordan structure of a matrix. Traditional notions such as sensitivity of subspaces are replaced with angles between tangent spaces of manifolds in n2-dimensional space. We show t... | Introduction
. The problem of accurately computing Jordan and Kronecker canonical structures
of matrices and pencils has captured the attention of many specialists in numerical linear algebra.
Standard algorithms for this process are denoted "staircase algorithms" because of the shape of the
resulting matrices [22, Pag... | kronecker structure;jordan structure;SVD;staircase algorithm;versal deformation |
347613 | Structure in Approximation Classes. | The study of the approximability properties of NP-hard optimization problems has recently made great advances mainly due to the results obtained in the field of proof checking. The last important breakthrough proves the APX-completeness of several important optimization problems and thus reconciles "two distinct views... | Introduction
In his pioneering paper on the approximation of combinatorial optimization problems [20],
David Johnson formally introduced the notion of approximable problem, proposed approximation
algorithms for several problems, and suggested a possible classification of optimization
problems on grounds of their approx... | approximation algorithms;complexity classes;reducibilities |
347814 | A computational study of routing algorithms for realistic transportation networks. | We carry out an experimental analysis of a number of shortest-path (routing) algorithms investigated in the context of the TRANSIMS (TRansportation ANalysis and SIMulation System) project. The main focus of the paper is to study how various heuristic as well as exact solutions and associated data structures affect the ... | Introduction
TRANSIMS is a multi-year project at the Los Alamos National Laboratory and is funded by the
Department of Transportation and by the Environmental Protection Agency. The main purpose
of TRANSIMS is to develop new methods for studying transportation planning questions. A
prototypical question considered in t... | shortest-paths algorithms;transportation planning;design and analysis of algorithms;network design;experimental analysis |
347863 | Automatic sampling with the ratio-of-uniforms method. | Applying the ratio-of-uniforms method for generating random variates results in very efficient, fast, and easy-to-implement algorithms. However parameters for every particular type of density must be precalculated analytically. In this article we show, that the ratio-of-uniforms method is also useful for the design of ... | Introduction
There exists a large literature on generation methods for standard continuous
distributions; see, for example, Devroye (1986). These algorithms are often especially
designed for a particular distribution and tailored to the features of each
density. However in many situations the application of standard di... | t-concave;rejection method;ratio of uniforms;universal method;nonuniform;adaptive method;random-number generation;log-concave |
348028 | Power optimization of technology-dependent circuits based on symbolic computation of logic implications. | This paper presents a novel approach to the problem of optimizing combinational circuits for low power. The method is inspired by the fact that power analysis performed on a technology mapped network gives more realistic estimates than it would at the technology-independent level. After each node's switching activity i... | INTRODUCTION
Excessive power dissipation in electronic circuits reduces reliability and battery
life. The severity of the problem increases with the level of transistor integra-
tion. Therefore, much work has been done on power optimization techniques at
all stages of the design process. During high-level design, power... | automation;logic design;design synthesis |
348058 | Efficient optimal design space characterization methodologies. | One of the primary advantages of a high-level synthesis system is its ability to explore the design space. This paper presents several methodologies for design space exploration that compute all optimal tradeoff points for the combined problem of scheduling, clock-length determination, and module selection. We discuss ... | INTRODUCTION
For many years, one of the most compelling reasons for developing high-level synthesis
systems [Gajski et al. 1994] [De Micheli 1994] has been the desire to quickly
explore a wide range of designs for the same behavioral description. Given a set
of designs, two metrics are commonly used to evaluate their q... | module selection;design space exploration;bounding;efficient searching;clock-length determination;scheduling;high-level synthesis |
348304 | Optimizing computations for effective block-processing. | Block-processing can decrease the time and power required to perform any given computation by simultaneously processing multiple samples of input data. The effectiveness of block-processing can be severely limited, however, if the delays in the dataflow graph of the computation are placed suboptimally. In this paper we... | Introduction
In many application domains, computations are defined on semi-infinite or very long streams
of data. The rate of the incoming data is dictated by the nature of the application and often
cannot be satisfied by a straightforward implementation of the specification. Although the
speed of hardware components h... | retiming;combinatorial optimization;computation dataflow graphs;embedded systems;integer linear programming;scheduling;high-level synthesis;vectorization |
348754 | Fast and flexible word searching on compressed text. | We present a fast compression technique for natural language texts. The novelties are that (1) decompression of arbitrary portions of the text can be done very efficiently, (2) exact search for words and phrases can be done on the compressed text directly, using any known sequential pattern-matching algorithm, and (3) ... | INTRODUCTION
In this paper we present an efficient compression technique for natural language
texts that allows fast and flexible searching of words and phrases. To search for
simple words and phrases, the patterns are compressed and the search proceeds
without any decoding of the compressed text. Searching words and p... | natural language text compression;word-based Huffman coding;compressed pattern matching;word searching |
348857 | Ontological Approach for Information Discovery in Internet Databases. | The Internet has solved the age-old problem of network connectivity and thus enabling the potential access to, and data sharing among large numbers of databases. However, enabling users to discover useful information requires an adequate metadata infrastructure that must scale with the diversity and dynamism of both us... | Introduction
The emergence of the Internet [?] and the World Wide Web (WWW) [?] have been
among the most important developments in the computer industry. Particularly,
the Web has brought a wave of new users and service providers to the Internet. It
is now the most popular distributed information repository. This globa... | internet databases;distributed ontologies;information discovery |
348872 | UML-Based integration testing. | Increasing numbers of software developers are using the Unified Modeling Language (UML) and associated visual modeling tools as a basis for the design and implementation of their distributed, component-based applications. At the same time, it is necessary to test these components, especially during unit and integration... | Figure
1: Alternating Bit Protocol Example
The example in Figure 1 represents an alternating bit
communication protocol2 in which there are four separate
components Timer, Transmitter, ComCh (Communication
Channel) and Receiver and several internal as well as external
interfaces and stimuli.
The protocol is a unidirec... | UML statecharts;COM/DCOM;test generation;CORBA;distributed components;test execution;functional testing |
348916 | Which pointer analysis should I use?. | During the past two decades many different pointer analysis algorithms have been published. Although some descriptions include measurements of the effectiveness of the algorithm, qualitative comparisons among algorithms are difficult because of varying infrastructure, benchmarks, and performance metrics. Without such... | INTRODUCTION
Programs written in languages with pointers can be troublesome
to analyze because the memory location accessed
through a pointer is not known by inspecting the statement.
To effectively analyze such languages, knowledge of pointer
behavior is required. Without such knowledge, conserva-
This copy is posted ... | interprocedural pointer analysis;data flow analysis |
348938 | Simplifying failure-inducing input. | Given some test case, a program fails. Which part of the test case is responsible for the particular failure? We show how our delta debugging algorithm generalizes and simplifies some failing input to a minimal test case that produces the failure.In a case study, the Mozilla web browser crashed after 95 user acti... | INTRODUCTION
Often people who encounter a bug spend a lot of time
investigating which changes to the input file will make the bug go
away and which changes will not affect it.
- Richard Stallman, Using and Porting GNU CC
The Mozilla engineers faced imminent doom. In July 1999, more
than 370 open bug reports were stored... | automated debugging;combinatorial testing |
349130 | Improving the precision of INCA by preventing spurious cycles. | The Inequality Necessary Condition Analyzer (INCA) is a finite-state verification tool that has been able to check properties of some very large concurrent systems. INCA checks a property of a concurrent system by generating a system of inequalities that must have integer solutions if the property can be violated. ... | INTRODUCTION
Finite-state verication tools deduce properties of nite-
state models of computer systems. They can be used to
check such properties as freedom from deadlock, mutually
exclusive use of a resource, and eventual response to a re-
quest. If the model represents all the executions of a system
(perhaps by makin... | INCA;integer programming;finite-state verification;cycles |
349141 | A thread-aware debugger with an open interface. | While threads have become an accepted and standardized model for expressing concurrency and exploiting parallelism for the shared-memory model, debugging threads is still poorly supported. This paper identifies challenges in debugging threads and offers solutions to them. The contributions of this paper are threefold.... | INTRODUCTION
Threads have become an accepted abstraction of concurrency
using the shared-memory programming paradigm and
provide the means to exploit parallelism in a shared-memory
multi-processor environment. Today, many thread implementations
adhere to the POSIX Threads (Pthreads) standard
[21], which denes a common ... | concurrency;open interface;debugging;active debugging;threads |
349154 | Upper and Lower Bounds on the Learning Curve for Gaussian Processes. | In this paper we introduce and illustrate non-trivial upper and lower bounds on the learning curves for one-dimensional Guassian Processes. The analysis is carried out emphasising the effects induced on the bounds by the smoothness of the random process described by the Modified Bessel and the Squared Exponential covar... | Introduction
A fundamental problem for systems learning from examples is to estimate
the amount of training samples needed to guarantee satisfactory generalisation
capabilities on new data. This is of theoretical interest but also of vital
practical importance; for example, algorithms which learn from data should
not b... | gaussian processes;bounds;generalisation error;bayesian inference |
349155 | Rapid Evaluation of Nonreflecting Boundary Kernels for Time-Domain Wave Propagation. | We present a systematic approach to the computation of exact nonreflecting boundary conditions for the wave equation. In both two and three dimensions, the critical step in our analysis involves convolution with the inverse Laplace transform of the logarithmic derivative of a Hankel function. The main technical result ... | argument, z, satisfying Im(z) 0. The number of poles is bounded by O log ||
log 1 +log2 ||+||1 log2 1 . A similar representation for derived which
is valid for Im(z) >0 requiring O log 1 log 1 +log 1 log log 1 +log 1 log log 1
poles.
In section 2, we introduce nonreflecting boundary kernels. In section 3 we collect
... | high-order convergence;wave equation;approximation;radiation boundary condition;nonreflecting boundary condition;absorbing boundary condition;maxwell's equations;bessel function |
349174 | Convergence Rates for Relaxation Schemes Approximating Conservation Laws. | In this paper, we prove a global error estimate for a relaxation scheme approximating scalar conservation laws. To this end, we decompose the error into a relaxation error and a discretization error. Including an initial error $\omega(\ep)$ we obtain the rate of convergence of $\sqrt{\ep}$ in L1 for the relaxation ste... | Introduction
be the unique global entropy solution in the sense of Kru-zkov [11] to
the Cauchy problem for the conservation law
with initial data
(IR). The solution u satisfies Kru-zkov's
entropy conditions
IAN, Otto-von-Guericke-Universit?t Magdeburg, PSF 4120, D-39016 Magdeburg, Germany. Supported
by an Alexander von... | convergence rate;relaxation model;relaxation scheme |
349319 | Improved spill code generation for software pipelined loops. | Software pipelining is a loop scheduling technique that extracts parallelism out of loops by overlapping the execution of several consecutive iterations. Due to the overlapping of iterations, schedules impose high register requirements during their execution. A schedule is valid if it requires at most the number of reg... | Introduction
Software pipelining [9] is an instruction scheduling technique that exploits instruction level
parallelism (ILP ) out of a loop by overlapping operations from various successive loop
iterations. Different approaches have been proposed in the literature [2] for the generation
of software pipelined schedules... | software pipelining;spill code;instruction-level parallelism;register allocation |
349336 | A generational on-the-fly garbage collector for Java. | An on-the-fly garbage collector does not stop the program threads to perform the collection. Instead, the collector executes in a separate thread (or process) in parallel to the program. On-the-fly collectors are useful for multi-threaded applications running on multiprocessor servers, where it is important to fully ut... | Introduction
Garbage collectors free the space held by unreachable (dead) objects so that this space can be reused in
future allocations. On multiprocessor platforms, it is not desirable to stop the program and perform the
collection in a single thread on one processor, as this leads both to long pause times and poor p... | memory management;programming languages;garbage collection;generational garbage collection |
350130 | Stochastic Grammatical Inference of Text Database Structure. | For a document collection in which structural elements are identified with markup, it is often necessary to construct a grammar retrospectively that constrains element nesting and ordering. This has been addressed by others as an application of grammatical inference. We describe an approach based on stochastic grammati... | Introduction
1.1. Text Structure
For electronically stored text, there are well known advantages to identifying structural
elements (e.g., chapters, titles, paragraphs, footnotes) with descriptive markup
[4, 5, 12]. Most commonly, markup is in the form of labeled tags interleaved with
the text as in the following examp... | text database structure;stochastic grammatical inference |
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