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350320 | A Comparison of Three Rounding Algorithms for IEEE Floating-Point Multiplication. | AbstractA new IEEE compliant floating-point rounding algorithm for computing the rounded product from a carry-save representation of the product is presented. The new rounding algorithm is compared with the rounding algorithms of Yu and Zyner [26] and of Quach et al. [17]. For each rounding algorithm, a logical descrip... | Introduction
Every modern microprocessor includes a
oating-point multiplier that complies with the IEEE
754 Standard [13]. The latency of the FP multiplier is critical to the
oating-point performance
since a large portion of the FP instructions consists of FP multiplications. For example, Oberman
reports that FP multip... | floating-point multiplication;IEEE 754 Standard;floating-point arithmetic;IEEE rounding |
350326 | Integer Multiplication with Overflow Detection or Saturation. | AbstractHigh-speed multiplication is frequently used in general-purpose and application-specific computer systems. These systems often support integer multiplication, where two $n$-bit integers are multiplied to produce a $2n$-bit product. To prevent growth in word length, processors typically return the $n$ least sign... | Introduction
1.1 Multiplication
Multiplication is an essential arithmetic operation for general purpose computers
and digital signal processors. High-performance systems support parallel multiplication
in hardware. Various high-speed parallel multipliers have been proposed and
realized. Most parallel multiplier designs... | integer;computer arithmetic;saturation;two's complement;tree multipliers;array multipliers;unsigned;overflow |
350566 | Computing Functions of a Shared Secret. | In this work we introduce and study threshold (t-out-of-n) secret sharing schemes for families of functions ${\cal F}$. Such schemes allow any set of at least t parties to compute privately the value f(s) of a (previously distributed) secret s, for any $f\in {\cal F}$. Smaller sets of players get no more information a... | Introduction
. Suppose, for example, that we are interested in sharing a
secret le among n parties in a way that will later allow any t of the parties to test
whether a particular string (not known in the sharing stage) appears in this le.
This test should be done without revealing the content of the whole le, or givin... | secret sharing;private computations;private channels;interaction;broadcast channel |
350571 | The Online Transportation Problem. | We study the online transportation problem under the assumption that the adversary has only half as many servers at each site as the online algorithm. We show that the GREEDY algorithm is $\Theta( {\rm min}(m, \lg C))$-competitive under this assumption, where m is the number of server sites and C is the total number of... | Introduction
We consider the natural online version of the well-known transportation problem
[2, 5]. The initial setting consists of a collection of server
sites in a metric space M. Each server site s j has a positive integral capacity c j .
The online algorithm A sees over time a sequence ng of requests for
service, ... | matching;online algorithms;competitive analysis |
350710 | Superlinear Convergence of an Interior-Point Method Despite Dependent Constraints. | We show that an interior-point method for monotone variational inequalities exhibits superlinear convergence provided that all the standard assumptions hold except for the well-known assumption that the Jacobian of the active constraints has full rank at the solution. We show that superlinear convergence occurs even wh... | Introduction
. We consider the following monotone variational inequality
over a closed convex set C ae
Find z 2 C such that (z
(1)
and the set C is defined by the following algebraic inequality:
. The mapping \Phi is assumed to be C 1 (continuously differentiable)
and monotone; that is,
while each component function g ... | interior-point method;superlinear convergence;monotone variational inequalities |
350715 | An Inexact Hybrid Generalized Proximal Point Algorithm and Some New Results on the Theory of Bregman Functions. | We present a new Bregman-function-based algorithm which is a modification of the generalized proximal point method for solving the variational inequality problem with a maximal monotone operator. The principal advantage of the presented algorithm is that it allows a more constructive error tolerance criterion in solvin... | Introduction
In this paper, we are concerned with proximal point algorithms for solving
the variational inequality problem. Specifically, we consider the methods
which are based on Bregman distance regularization. Our objective is two-
fold. First of all, we develop a hybrid algorithm based on inexact solution of
proxi... | maximal monotone operator;bregman function;variational inequality;proximal point method |
351137 | Performance Evaluation of Conservative Algorithms in Parallel Simulation Languages. | AbstractParallel discrete event simulation with conservative synchronization algorithms has been used as a high performance alternative to sequential simulation. In this paper, we examine the performance of a set of parallel conservative algorithms that have been implemented in the Maisie parallel simulation language. ... | Introduction
Parallel discrete event simulation (PDES) refers to the execution of a discrete event simulation
program on parallel or distributed computers. Several algorithms have been developed to synchronize
the execution of PDES models, and a number of studies have attempted to evaluate the performance
of these algo... | lookahead;parallel simulation languages;discrete-event simulation;algorithmic efficiency;parallel and distributed simulation;conservative algorithms |
351138 | Modeling and Performance Comparison of Reliability Strategies for Distributed Video Servers. | AbstractLarge scale video servers are typically based on disk arrays that comprise multiple nodes and many hard disks. Due to the large number of components, disk arrays are susceptible to disk and node failures that can affect the server reliability. Therefore, fault tolerance must be already addressed in the design o... | Introduction
1.1 Server Design Issues
Many multimedia applications such as online news, interactive television, and video-on-demand require large
video servers that are capable of transmitting video data to thousands of users. In contrary to traditional file
systems, video servers are subject to real-time constraints t... | reliability modeling;performance and cost analysis;distributed video servers;SHARPE;markov chains |
351186 | A PTAS for Minimizing the Total Weighted Completion Time on Identical Parallel Machines. | We consider the problem of scheduling a set ofn jobs onm identical parallel machines so as to minimize the weighted sum of job completion times. This problem is NP-hard in the strong sense. The best approximation result known so far was a 1/2 (1 2)-approximation algorithm that has been derived by Kawaguchi and Kyan bac... | Introduction
The problem. We consider the following machine scheduling model. We are given a set J of n independent
jobs that have to be scheduled on m identical parallel machines or processors. Each job
is specified by its positive processing requirement p j and by its positive weight w j . In a feasible schedule
for ... | approximation scheme;combinatorial optimization;worst-case ratio;scheduling theory;approximation algorithm |
351414 | Machine-adaptable dynamic binary translation. | Dynamic binary translation is the process of translating and optimizing executable code for one machine to another at runtime, while the program is executing on the target machine. Dynamic translation techniques have normally been limited to two particular machines; a competitor's machine and the hardware manufacturer'... | INTRODUCTION
Binary translation is a migration technique that allows software
to run on other machines achieving near native code
performance. Binary translation grew out of emulation
techniques in the late 1980s in order to provide for a migration
path from legacy CISC machines to the newer RISC machines.
Such techniq... | dynamic execution;binary translation;interpretation;emulation;dynamic compilation |
351523 | On the Eigenvalues of the Volume Integral Operator of Electromagnetic Scattering. | The volume integral equation of electromagnetic scattering can be used to compute the scattering by inhomogeneous or anisotropic scatterers. In this paper we compute the spectrum of the scattering integral operator for a sphere and the eigenvalues of the coefficient matrices that arise from the discretization of the in... | Introduction
. The convergence of iterative solvers for systems of linear equations is closely related
to the eigenvalue distribution of the coefficient matrix. To be able to predict the convergence of
iterative solvers one therefore needs to look at how the matrix and its eigenvalues arise from a discretization
of a p... | electromagnetic scattering;spectrum of linear operators;eigenvalues of matrices;iterative methods;integral equations |
351531 | A Priori Sparsity Patterns for Parallel Sparse Approximate Inverse Preconditioners. | Parallel algorithms for computing sparse approximations to the inverse of a sparse matrix either use a prescribed sparsity pattern for the approximate inverse or attempt to generate a good pattern as part of the algorithm. This paper demonstrates that, for PDE problems, the patterns of powers of sparsified matrices (P... | Introduction
. A sparse approximate inverse approximates the inverse of a
(usually sparse) matrix A by a sparse matrix M . This can be accomplished, for
example in the least-squares method, by minimizing the matrix residual norm 1
F
with the constraint that M is sparse. In general, the degrees of freedom of this
proble... | preconditioned iterative methods;graph theory;sparse approximate inverses;parallel computing |
351534 | Mesh Independence of Matrix-Free Methods for Path Following. | In this paper we consider a matrix-free path following algorithm for nonlinear parameter-dependent compact fixed point problems. We show that if these problems are discretized so that certain collective compactness and strong convergence properties hold, then this algorithm can follow smooth folds and capture simple bi... | Introduction
. The purpose of this paper is to extend the results in [4], [5], and [16] on
mesh-independent convergence of the GMRES, [21], iterative method for linear equations to a
class of matrix-free methods for solution of parameter dependent nonlinear equations of the form
In Banach space.
We present an algorithm... | fold point;bifurcation;arnoldi method;singularity;matrix-free method;GMRES;path following;collective compactness;mesh independence |
351540 | Robustness and Scalability of Algebraic Multigrid. | Algebraic multigrid (AMG) is currently undergoing a resurgence in popularity, due in part to the dramatic increase in the need to solve physical problems posed on very large, unstructured grids. While AMG has proved its usefulness on various problem types, it is not commonly understood how wide a range of applicability... | Introduction
. Algebraic multigrid (AMG) was rst introduced in the early
1980's [11, 8, 10, 12], and immediately attracted substantial interest [32, 28, 30, 29].
Research continued at a modest pace into the late 1980's and early 1990's [18, 14, 21,
25, 20, 26, 22]. Recently, however, there has been a major resurgence o... | scalability;algebraic multigrid;interpolation;unstructured meshes |
351544 | Observability of 3D Motion. | This paper examines the inherent difficulties in observing 3D rigid motion from image sequences. It does so without considering a particular estimator. Instead, it presents a statistical analysis of all the possible computational models which can be used for estimating 3D motion from an image sequence. These computatio... | Introduction
Visual Servoing and Motion Estimation
A broad definition of visual servoing amounts to the control of motion on the basis of image analysis. Thus,
a driver adjusting the turning of the wheel by monitoring some features in the scene, a system attempting to
insert a peg through a hole, a controller at some c... | positive depth constraint;error analysis;epipolar constraint;3D motion estimation |
351545 | First-Order System Least-Squares for the Helmholtz Equation. | This paper develops a multilevel least-squares approach for the numerical solution of the complex scalar exterior Helmholtz equation. This second-order equation is first recast into an equivalent first-order system by introducing several "field" variables. A combination of scaled L2 and H-1 norms is then applied to the... | Introduction
. The scalar Helmholtz equation with exterior radiation boundary
conditions describes a variety of wave propagation phenomena. One such phenomenon
is the electromagnetic scattering of time-harmonic waves, which, since the
advent of stealth technology, has helped propel an interest in e#cient numerical solu... | first-order system least-squares;helmholtz equation;nonstandard multigrid |
351604 | Robust Real-Time Periodic Motion Detection, Analysis, and Applications. | AbstractWe describe new techniques to detect and analyze periodic motion as seen from both a static and a moving camera. By tracking objects of interest, we compute an object's self-similarity as it evolves in time. For periodic motion, the self-similarity measure is also periodic and we apply Time-Frequency analysis t... | Introduction
Object motions that repeat are common in both nature and the man-made environment in which we
live. Perhaps the most prevalent periodic motions are the ambulatory motions made by humans and
animals in their gaits (commonly referred to as "biological motion" [16]). Other examples include
a person walking, a... | motion-based recognition;periodic motion;motion segmention;object classification;person detection;motion symmetries |
351607 | A Bayesian Computer Vision System for Modeling Human Interactions. | AbstractWe describe a real-time computer vision and machine learning system for modeling and recognizing human behaviors in a visual surveillance task [1]. The system is particularly concerned with detecting when interactions between people occur and classifying the type of interaction. Examples of interesting interact... | Introduction
We describe a real-time computer vision and machine
learning system for modeling and recognizing human
behaviors in a visual surveillance task. The system
is particularly concerned with detecting when interactions
between people occur, and classifying the type
of interaction.
Over the last decade there has... | Hidden Markov Models;tracking;visual surveillance;human behavior recognition;people detection |
351611 | Normalized Cuts and Image Segmentation. | AbstractWe propose a novel approach for solving the perceptual grouping problem in vision. Rather than focusing on local features and their consistencies in the image data, our approach aims at extracting the global impression of an image. We treat image segmentation as a graph partitioning problem and propose a novel ... | Introduction
Nearly launched the Gestalt approach which laid out the
importance of perceptual grouping and organization in visual perception. For our purposes,
the problem of grouping can be well motivated by considering the set of points shown in the
figure (1).
Figure
1: How many groups?
Typically a human observer ... | graph partitioning;image segmentation;grouping |
352648 | A Comparison of Prediction Accuracy, Complexity, and Training Time of Thirty-Three Old and New Classification Algorithms. | Twenty-two decision tree, nine statistical, and two neural network algorithms are compared on thirty-two datasets in terms of classification accuracy, training time, and (in the case of trees) number of leaves. Classification accuracy is measured by mean error rate and mean rank of error rate. Both criteria place a sta... | Introduction
There is much current research in the machine learning and statistics communities
on algorithms for decision tree classifiers. Often the emphasis is on the accuracy of
the algorithms. One study, called the StatLog Project (Michie, Spiegelhalter and
Taylor, 1994), compares the accuracy of several decision t... | decision tree;classification tree;statistical classifier;neural net |
352664 | A Study of Reinforcement Learning in the Continuous Case by the Means of Viscosity Solutions. | This paper proposes a study of Reinforcement Learning (RL) for continuous state-space and time control problems, based on the theoretical framework of viscosity solutions (VSs). We use the method of dynamic programming (DP) which introduces the value function (VF), expectation of the best future cumulative reinforcemen... | Introduction
This paper is about Reinforcement Learning (RL) in the continuous state-space and
time case. RL techniques (see (Kaelbling, Littman, & Moore, 1996) for a survey)
are adaptive methods for solving optimal control problems for which only a partial
amount of initial data are available to the system that learns... | optimal control;reinforcement learning;viscosity solutions;finite difference and finite element methods;dynamic programming;Hamilton-Jacobi-Bellman equation |
352748 | Robust Plane Sweep for Intersecting Segments. | In this paper, we reexamine in the framework of robust computation the Bentley--Ottmann algorithm for reporting intersecting pairs of segments in the plane. This algorithm has been reported as being very sensitive to numerical errors. Indeed, a simple analysis reveals that it involves predicates of degree 5, presumably... | Introduction
As is well known, Computational Geometry has traditionally adopted the arithmetic
model of exact computation over the real numbers. This model has been extremely
productive in terms of algorithmic research, since it has permitted a vast community
to focus on the elucidation of the combinatorial (topologica... | segment intersection;robust algorithms;plane sweep;computational geometry |
352753 | Binary Space Partitions for Fat Rectangles. | We consider the practical problem of constructing binary space partitions (BSPs) for a set S of n orthogonal, nonintersecting, two-dimensional rectangles in ${\Bbb R}^3$ such that the aspect ratio of each rectangle in $S$ is at most $\alpha$, for some constant $\alpha \geq 1$. We present an $n2^{O(\sqrt{\log n})}$-time... | Introduction
How to render a set of opaque or partially transparent objects
in IR 3 in a visually realistic way is a fundamental problem
in computer graphics [12, 22]. A central component of
this problem is hidden-surface removal: given a set of ob-
jects, a viewpoint, and an image plane, compute the scene
visible from... | solid modelling;aspect ratio;computer graphics;computational geometry;binary space partitions;rectangles |
352757 | An Optimal Algorithm for Monte Carlo Estimation. | A typical approach to estimate an unknown quantity $\mu$ is to design an experiment that produces a random variable Z, distributed in [0,1] with E[Z]=\mu$, run this experiment independently a number of times, and use the average of the outcomes as the estimate. In this paper, we consider the case when no a priori inf... | Introduction
The choice of experiment, or experimental design, forms an important aspect of statistics.
One of the simplest design problems is the problem of deciding when to stop sampling.
For example, suppose Z are independently and identically distributed according
to Z in the interval [0; 1] with mean -Z . From Ber... | monte carlo estimation;sequential estimation;stochastic approximation;stopping rule;approximation algorithm |
352762 | Separating Complexity Classes Using Autoreducibility. | A set is autoreducible if it can be reduced to itself by a Turing machine that does not ask its own input to the oracle. We use autoreducibility to separate the polynomial-time hierarchy from exponential space by showing that all Turing complete sets for certain levels of the exponential-time hierarchy are autoreducib... | Introduction
While complexity theorists have made great strides in understanding the structure of complexity
classes, they have not yet found the proper tools to do nontrivial separation of complexity classes
such as P and NP. They have developed sophisticated diagonalization, combinatorial and algebraic
techniques but... | complexity classes;autoreducibility;completeness;coherence |
352775 | Self-Testing without the Generator Bottleneck. | Suppose P is a program designed to compute a function f defined on a group G. The task of self-testing P, that is, testing if P computes f correctly on most inputs, usually involves testing explicitly if P computes f correctly on every generator of G. In the case of multivariate functions, the number of generators, and... | Introduction
. The notions of program result-checking, self-testing, and self-correcting
as introduced in [4, 17, 5] are powerful tools for attacking the problem
of program correctness. These methods offer both realistic and efficient tools for
software verification. Various useful mathematical functions have been show... | program correctness;generator bottleneck;self-testing |
353196 | An approach to safe object sharing. | It is essential for security to be able to isolate mistrusting programs from one another, and to protect the host platform from programs. Isolation is difficult in object-oriented systems because objects can easily become aliased. Aliases that cross program boundaries can allow programs to exchange information without ... | Introduction
In the age of Internet programming, the importance of sound
security mechanisms for systems was never greater. A host
can execute programs from unknown network sources, so it
needs to be able to run each program in a distinct protection
domain. A program running in a protection domain is
prevented from acc... | access control;protection domains;sharing;aliasing |
353280 | Merging and Splitting Eigenspace Models. | AbstractWe present new deterministic methods that given two eigenspace modelseach representing a set of $n$-dimensional observationswill: 1) merge the models to yield a representation of the union of the sets and 2) split one model from another to represent the difference between the sets. As this is done, we accuratel... | Introduction
The contributions of this paper are: (1) a method for
merging eigenspace models; (2) a method for splitting
eigenspace models. These represent an advance in
that previous methods for incremental computation
of eigenspace models considered only the addition (or
subtraction) of a single observation to (or fr... | principal component analysis;eigenspace models;model merging;model splitting;gaussian mixture models |
353382 | Enforceable security policies. | A precise characterization is given for the class of security policies enforceable with mechanisms that work by monitoring system execution, and automata are introduced for specifying exactly that class of security policies. Techniques to enforce security policies specified by such automata are also discussed. | Introduction
A security policy defines execution that, for one reason or another, has been
deemed unacceptable. For example, a security policy might concern
access control, and restrict what operations principals can perform on
objects,
ffl information flow, and restrict what things principals can infer about
objects f... | security automata;security policies;safety properties;proof carrying code;SASI;EM security policies;inlined reference monitors |
353938 | Integrating object-oriented programming and protected objects in Ada 95. | Integrating concurrent and object-oriented programming has been an active research topic since the late 1980's. There is a now a plethora of methods for achieving this integration. The majority of approaches have taken a sequential object-oriented language and made it concurrent. A few approaches have taken a concurren... | Introduction
Arguably, Ada 95 does not fully integrate its models of concurrent and object-oriented
programming (Atkinson and Weller, 1993; Wellings et al., 1996; Burns
and Wellings, 1998). For example, neither tasks nor protected objects are exten-
sible. When Ada 95 was designed, the extensions to Ada 83 for object-o... | concurrency;concurrent object-oriented programming;ada 95;inheritance anomaly |
353944 | Data Dependence Analysis of Assembly Code. | Determination of data dependences is a task typically performed with high-level language source code in today's optimizing and parallelizing compilers. Very little work has been done in the field of data dependence analysis on assembly language code, but this area will be of growing importance, e.g., for increasing ins... | Introduction
The determination of data dependences is nowadays
most often done by parallelizing and optimizing compiler
systems on the level of source code, e.g. C or FORTRAN
90, or some intermediate code, e.g. RTL [21]. Data
dependence analysis on the level of assembly code aims
at increasing instruction level paralle... | assembly code;memory reference disambiguation;value-based dependences;monotone data flow frameworks;data dependence analysis |
353947 | Loop Shifting for Loop Compaction. | The idea of decomposed software pipelining is to decouple the software pipelining problem into a cyclic scheduling problem without resource constraints and an acyclic scheduling problem with resource constraints. In terms of loop transformation and code motion, the technique can be formulated as a combination of loop s... | Introduction
Modern computers now exploit parallelism at the instruction level in the microprocessor itself. A
sequential microprocessor is not anymore a simple unit that processes instructions following a
unique stream. The processor may have multiple independent functional units, some pipelined
and possibly some othe... | list scheduling;software pipelining;cyclic scheduling;circuit retiming |
353953 | Efficient Rule-Based Attribute-Oriented Induction for Data Mining. | Data mining has become an important technique which has tremendous potential in many commercial and industrial applications. Attribute-oriented induction is a powerful mining technique and has been successfully implemented in the data mining system DBMiner (Han et al. Proc. 1996 Int'l Conf. on Data Mining and Knowledge... | Introduction
Data mining (also known as Knowledge Discovery in Databases) is the nontrivial extraction of implicit,
previously unknown, and potentially useful information from data [12]. Over the past twenty years, huge
amounts of data have been collected and managed in relational databases by industrial, commercial or... | data mining;rule-based concept hierarchy;rule-based concept generalization;inductive learning;learning and adaptive systems;attribute-oriented induction;knowledge discovery in databases |
354178 | The FERET Evaluation Methodology for Face-Recognition Algorithms. | AbstractTwo of the most critical requirements in support of producing reliable face-recognition systems are a large database of facial images and a testing procedure to evaluate systems. The Face Recognition Technology (FERET) program has addressed both issues through the FERET database of facial images and the establi... | Introduction
Over the last decade, face recognition has become an active area of research in computer
vision, neuroscience, and psychology. Progress has advanced to the point that
face-recognition systems are being demonstrated in real-world settings [5]. The rapid development
of face recognition is due to a combinatio... | face recognition;algorithm evaluation;FERET database |
354183 | Completion Energies and Scale. | AbstractThe detection of smooth curves in images and their completion over gaps are two important problems in perceptual grouping. In this study, we examine the notion of completion energy of curve elements, showing, and exploiting its intrinsic dependence on length and width scales. We introduce a fast method for comp... | Introduction
The smooth completion of fragmented curve segments
is a skill of the human visual system that has been demonstrated
through many compelling examples. Due to this skill
people often are able to perceive the boundaries of objects
even in the lack of sufficient contrast or in the presence of oc-
clusions. A n... | elastica curve;multiscale;induction field;completion field;perceptual grouping;fast summation;scale;least-energy curve;curve completion;curve saliency |
354191 | Self-Calibration of a 1D Projective Camera and Its Application to the Self-Calibration of a 2D Projective Camera. | AbstractWe introduce the concept of self-calibration of a 1D projective camera from point correspondences, and describe a method for uniquely determining the two internal parameters of a 1D camera, based on the trifocal tensor of three 1D images. The method requires the estimation of the trifocal tensor which can be ac... | Introduction
A CCD camera is commonly modeled as a 2D projective device that projects a point in P 3 (the
projective space of dimension 3) to a point in P 2 . By analogy, we can consider what we call a 1D
projective camera which projects a point in P 2 to a point in P 1 . This 1D projective camera may seem
very abstrac... | self-calibration;camera model;vision geometry;planar motion;1D camera |
354357 | Look-Ahead Procedures for Lanczos-Type Product Methods Based on Three-Term Lanczos Recurrences. | Lanczos-type product methods for the solution of large sparse non-Hermitian linear systems either square the Lanczos process or combine it with a local minimization of the residual. They inherit from the underlying Lanczos process the danger of breakdown. For various Lanczos-type product methods that are based on the L... | Introduction
. Lanczos-type product methods (LTPMs) like (Bi)CGS [42],
BiCGStab [44], BiCGStab2 [22], and BiCGStab(') [38], [41] are among the most
efficient methods for solving large systems of linear equations
sparse system matrix A 2 C
N \ThetaN . Compared to the biconjugate gradient
method they have the advantage o... | lanczos-type product methods;look-ahead;sparse linear systems;non-Hermitian matrices;iterative methods |
354387 | A Block Algorithm for Matrix 1-Norm Estimation, with an Application to 1-Norm Pseudospectra. | The matrix 1-norm estimation algorithm used in LAPACK and various other software libraries and packages has proved to be a valuable tool. However, it has the limitations that it offers the user no control over the accuracy and reliability of the estimate and that it is based on level 2 BLAS operations. A block generali... | Introduction
. Research in matrix condition number estimation began in the
1970s with the problem of cheaply estimating the condition number
and an approximate null vector of a square matrix A given some factorization of
it. The earliest algorithm is one of Gragg and Stewart [10]. It was improved by
Cline, Moler, Stewa... | LAPACK;matrix condition number;p-norm power method;level 3 BLAS;1-norm pseudospectrum;condition number estimation;matrix 1-norm;matrix norm estimation |
354402 | Constraint Preconditioning for Indefinite Linear Systems. | The problem of finding good preconditioners for the numerical solution of indefinite linear systems is considered. Special emphasis is put on preconditioners that have a 2 2 block structure and that incorporate the (1,2) and (2,1) blocks of the original matrix. Results concerning the spectrum and form of the eigenvec... | Introduction
In this paper we are concerned with investigating a new class of preconditioners
for indefinite systems of linear equations of a sort which arise in constrained
optimization as well as in least-squares, saddle-point and Stokes problems. We
attempt to solve the indefinite linear system
A
where A 2 IR n\Thet... | indefinite matrices;preconditioning;krylov subspace methods |
354647 | A bandwidth analysis of reliable multicast transport protocols. | Multicast is an efficient communication technique to save bandwidth for group communication purposes. A number of protocols have been proposed in the past to provide a reliable multicast service. Briefly classified, they can be distinguished into sender-initiated, receiver-initiated and tree-based approaches. In this p... | INTRODUCTION
A number of reliable multicast transport protocols have been
proposed in the literature, which are based on the acknowledgment
scheme. Reliability is ensured by replying acknowledgment
messages from the receivers to the sender, either
Permission to make digital or hard copies of all or part of this work fo... | analysis;receiver-initiated;bandwidth;tree-based;reliable multicast;sender-initiated;AAK |
354704 | Parametric Analysis of Computer Systems. | A general parametric analysis problem which allows the use of parameter variables in both the real-time automata and the specifications is proposed and solved. The analysis algorithm is much simpler and can run more efficiently in average cases than can previous works. | Introduction
A successful real-world project management relies on the satisfaction of various timing and nontiming restraints
which may compete with each other for resources. Examples of such restraints include timely re-
sponses, budget, domestic or international regulations, system configurations, environments, compa... | real-time systems;parameters;verification;model-checking |
354705 | Modelling IP Mobility. | We study a highly simplified version of the proposed mobility support in version 6 of Internet Protocols (IP). We concentrate on the issue of ensuring that messages to and from mobile agents are delivered without loss of connectivity. We provide three models, of increasingly complex nature, of a network of routers and ... | Introduction
We study the modelling of mobile hosts on a network using a simple process
description language, with the intention of being able to prove properties about a
protocol for supporting mobility. The present case study grew out of our interest in
understanding the essential aspects of some extant mechanisms pr... | internet protocols;formal methods;mobility;bisimulation;modelling;process description languages;protocol analysis;verification |
354864 | Design and Evaluation of a Switch Cache Architecture for CC-NUMA Multiprocessors. | AbstractCache coherent nonuniform memory access (CC-NUMA) multiprocessors provide a scalable design for shared memory. But, they continue to suffer from large remote memory access latencies due to comparatively slow memory technology and large data transfer latencies in the interconnection network. In this paper, we pr... | Introduction
To alleviate the problem of high memory access latencies, shared memory multiprocessors employ
processors with small fast on-chip caches and additionally larger off-chip caches. Symmetric multiprocessor
(SMP) systems are usually built using a shared global bus. However the contention on
the bus and memory ... | shared memory multiprocessors;wormhole routing;crossbar switches;scalable interconnects;cache architectures;execution-driven simulation |
354866 | Properties of Rescheduling Size Invariance for Dynamic Rescheduling-Based VLIW Cross-Generation Compatibility. | AbstractThe object-code compatibility problem in VLIW architectures stems from their statically scheduled nature. Dynamic rescheduling (DR) [1] is a technique to solve the compatibility problem in VLIWs. DR reschedules program code pages at first-time page faults, i.e., when the code pages are accessed for the first ti... | Introduction
The object-code compatibility problem in VLIW architectures stems from their statically
scheduled nature. The compiler for a VLIW machine schedules code for a specific machine
model (or a machine generation), for precise, cycle-by-cycle execution at run-time. The
machine model assumptions for a given code ... | list encoding;instruction cache;VLIW;microarchitecture;processor architecture;instruction-set encoding |
354867 | Computing Orthogonal Drawings with the Minimum Number of Bends. | AbstractWe describe a branch-and-bound algorithm for computing an orthogonal grid drawing with the minimum number of bends of a biconnected planar graph. Such an algorithm is based on an efficient enumeration schema of the embeddings of a planar graph and on several new methods for computing lower bounds of the number ... | Introduction
Various graphic standards have been proposed to draw graphs, each one devoted
to a specific class of applications. An extensive literature on the subject can be
found in [4, 23, 2]. In particular, an orthogonal drawing maps each edge into a
chain of horizontal and vertical segments and an orthogonal grid d... | planar embedding;orthogonal drawings;bends;branch and bound;planar graphs;graph drawing |
354877 | Xor-trees for efficient anonymous multicast and reception. | We examine the problem of efficient anonymous multicast and reception in general communication networks. We present algorithms that achieve anonymous communication, are protected against traffic analysis, and require O(1) amortized communication complexity on each link and low computational comlexity. The algorithms su... | Introduction
One of the primary objectives of an adversary is to locate and to destroy command-and-control
centers - that is, sites that send commands and data to various stations/agents. Hence, one
of the crucial ingredients in almost any network with command centers is to conceal and
to confuse the adversary regardin... | anonymous communication;anonymous multicast |
354878 | Configuring role-based access control to enforce mandatory and discretionary access control policies. | Access control models have traditionally included mandatory access control (or lattice-based access control) and discretionary access control. Subsequently, role-based access control has been introduced, along with claims that its mechanisms are general enough to simulate the traditional methods. In this paper we provi... | INTRODUCTION
Role-based access control (RBAC) has recently received considerable attention as
a promising alternative to traditional discretionary and mandatory access controls
(see, for example, Proceedings of the ACM Workshop on Role-Based Access Con-
trol, 1995-2000). In RBAC, permissions are associated with roles, ... | mandatory access control;lattice-based access control;role-based access control;discretionary access control |
355051 | Automated systematic testing for constraint-based interactive services. | Constraint-based languages can express in a concise way the complex logic of a new generation of interactive services for applications such as banking or stock trading, that must support multiple types of interfaces for accessing the same data. These include automatic speech-recognition interfaces where inputs may be p... | INTRODUCTION
Today, it is becoming more and more commonplace for modern
interactive services, such as those for personal banking or stock
trading, to have more than one interface for accessing the same
data. For example, many banks allow customers to access personal
banking services from an automated teller machine, ba... | model checking;interactive services;testing;state-space reduction;constraint-based languages;state explosion;verification |
355188 | Interpreting Stale Load Information. | AbstractIn this paper, we examine the problem of balancing load in a large-scale distributed system when information about server loads may be stale. It is well-known that sending each request to the machine with the apparent lowest load can behave badly in such systems, yet this technique is common in practice. Other ... | Introduction
When balancing load in a distributed system, it is well known that the strategy of sending
each request to the least-loaded machine can behave badly if load information is old [11,
18, 21]. In such systems a "herd effect" often develops, and machines that appear to be
underutilized quickly become overloade... | server selection;load balancing;distributed systems;queuing theory;stale information |
355190 | A Protocol-Centric Approach to on-the-Fly Race Detection. | AbstractWe present the design and evaluation of a new data-race-detection technique. Our technique executes at runtime rather than post-mortem, and handles unmodified shared-memory applications that run on top of CVM, a software distributed shared memory system. We do not assume explicit associations between synchroniz... | Introduction
Despite the potential savings in time and effort, data-race detection techniques are not yet an accepted tool of builders
of parallel and distributed systems. Part of the problem is surely the restricted domain in which most such mechanisms
operate, i.e., parallelizing compilers. Compiler support is usuall... | shared memory;DSM;data races;on-the-fly |
355277 | Metric operations on fuzzy spatial objects in databases. | Uncertainty management for geometric data is currently an important problem for (extensible) databases in general and for spatial databases, image databases, and GIS in particular. In these systems, spatial data are traditionally kept as determinate and sharply bounded objects; the aspect of spatial vagueness is not an... | INTRODUCTION
Representing, storing, quering, and manipulating spatial information
is important for many non-standard database applications. But
so far, spatial data modeling has implicitly assumed that the extent
and hence the borders of spatial objects are precisely determined
("boundary syndrome"). Special data types... | fuzzy sets;fuzzy-valued metric operation;fuzzy line;real-valued metric operation;fuzzy region;fuzzy spatial data type |
355442 | The Volumetric Barrier for Semidefinite Programming. | We consider the volumetric barrier for semidefinite programming, or "generalized" volumetric barrier, as introduced by Nesterov and Nemirovskii. We extend several fundamental properties of the volumetric barrier for a polyhedral set to the semidefinite case. Our analysis facilitates a simplified proof of self-concordan... | Introduction
This paper concerns the volumetric barrier for semidefinite programming. The volumetric
barrier for a polyhedral set A is an m \Theta n matrix, was introduced
by Vaidya (1996). Vaidya used the volumetric barrier in the construction of a cutting plane
algorithm for convex programming; see also Anstreicher (... | self-concordance;volumetric barrier;semidefinite programming |
355443 | General Interior-Point Maps and Existence of Weighted Paths for Nonlinear Semidefinite Complementarity Problems. | Extending the previous work of Monteiro and Pang (1998), this paper studies properties of fundamental maps that can be used to describe the central path of the monotone nonlinear com-plementarity problems over the cone of symmetric positive semidefinite matrices. Instead of focusing our attention on a specific map as w... | Introduction
section1
In a series of recent papers (see Kojima, Shida and Shindoh 1997, 1998, 1999, Kojima, Shindoh
and Hara 1997, Shida and Shindoh 1996, Shida, Shindoh and Kojima 1997, 1998), Hara, Kojima,
Shida and Shindoh have introduced the monotone complementarity problem in symmetric matrices,
studied its proper... | interior point methods;maximal monotonicity;generalized complementarity problems;monotone maps;mixed nonlinear complementarity problems;nonlinear semidefinite programming;weighted central path;continuous trajectories |
355485 | Building tractable disjunctive constraints. | Many combinatorial search problems can be expressed as 'constraint satisfaction problems'. This class of problems is known to be NP-hard in general, but a number of restricted constraint classes have been identified which ensure tractability. This paper presents the first general results on combining tractable constrai... | INTRODUCTION
Many combinatorial search problems can be expressed as 'constraint satisfaction
problems' [Montanari 1974; Mackworth 1977], in which the aim is to nd an assignment
of values to a given set of variables subject to specied constraints. For ex-
ample, the standard propositional satisability problem [Garey and... | constraint satisfaction problem;relations;complexity;NP-completeness;disjunctive constraints;independence |
356483 | The CREW PRAM Complexity of Modular Inversion. | One of the long-standing open questions in the theory of parallel computation is the parallel complexity of the integer gcd and related problems, such as modular inversion. We present a lower bound $\Omega (\log n)$ for the parallel time on a concurrent-read exclusive-write parallel random access machine (CREW PRAM) co... | Introduction
. In this paper we address the problem of parallel computation of the inverse of
integers modulo an integer M . That is, given positive integers M # 3 and x < M , with gcd(x,
we want to compute its modular inverse inv M (x) # N defined by the conditions
is the Euler function, inversion can be considered as... | parallel computation;CREW PRAM complexity;exponential sums;modular inversion |
356488 | On Interpolation and Automatization for Frege Systems. | The interpolation method has been one of the main tools for proving lower bounds for propositional proof systems. Loosely speaking, if one can prove that a particular proof system has the feasible interpolation property, then a generic reduction can (usually) be applied to prove lower bounds for the proof system, some... | Introduction
One of the most important questions in propositional proof complexity is to show that there is a
family of propositional tautologies requiring superpolynomial size proofs in a Frege or Extended
Frege proof system. The problem is still open, and it is thus a very important question to
understand which techn... | diffie-hellman;threshold circuits;propositional proof systems;frege proof systems |
356491 | Constructing Planar Cuttings in Theory and Practice. | We present several variants of a new randomized incremental algorithm for computing a cutting in an arrangement of n lines in the plane. The algorithms produce cuttings whose expected size is O(r2), and the expected running time of the algorithms is O(nr). Both bounds are asymptotically optimal for nondegenerate arrang... | Introduction
A natural approach for solving various problems in computational geometry is the divide-and-
conquer paradigm. A typical application of this paradigm to problems involving a set L of n
lines in the plane, is to fix a parameter r ? 0, and to partition the plane into regions R
(those regions are usually vert... | range-searching;cuttings;computational geometry |
356493 | Gadgets, Approximation, and Linear Programming. | We present a linear programming-based method for finding "gadgets," i.e., combinatorial structures reducing constraints of one optimization problem to constraints of another. A key step in this method is a simple observation which limits the search space to a finite one. Using this new method we present a number of ne... | Introduction
. A \gadget" is a nite combinatorial structure which translates
a given constraint of one optimization problem into a set of constraints of a
second optimization problem. A classical example is in the reduction from 3SAT to
MAX 2SAT, due to Garey, Johnson and Stockmeyer [6]. Given an instance of 3SAT
on va... | reductions;intractability;combinatorial optimization;approximation algorithms;NP-completeness;probabilistic proof systems |
357383 | An Evaluation of Statistical Approaches to Text Categorization. | This paper focuses on a comparative evaluation of a wide-range of text categorization methods, including previously published results on the Reuters corpus and new results of additional experiments. A controlled study using three classifiers, kNN, LLSF and WORD, was conducted to examine the impact of configuration ... | Introduction
Text categorization is the problem of assigning predefined categories to free text documents. A growing number of
statistical learning methods have been applied to this problem in recent years, including regression models[5, 18],
nearest neighbor classifiers[3, 19], Bayes belief networks [14, 9], decision ... | comparative study;evaluation;text categorization;statistical learning algorithms |
357485 | Secure Execution of Java Applets Using a Remote Playground. | AbstractMobile code presents a number of threats to machines that execute it. We introduce an approach for protecting machines and the resources they hold from mobile code and describe a system based on our approach for protecting host machines from Java 1.1 applets. In our approach, each Java applet downloaded to the ... | Introduction
Advances in mobile code, particularly Java, have
considerably increased the exposure of networked computers
to attackers. Due to the "push" technologies
that often deliver such code, an attacker can download
and execute programs on a victim's machine without
the victim's knowledge or consent. The attacker'... | security;remote method invocation;mobile code |
357769 | An Optimal Hardware-Algorithm for Sorting Using a Fixed-Size Parallel Sorting Device. | AbstractWe present a hardware-algorithm for sorting $N$ elements using either a p-sorter or a sorting network of fixed I/O size $p$ while strictly enforcing conflict-free memory accesses. To the best of our knowledge, this is the first realistic design that achieves optimal time performance, running in $\Theta ( {\frac... | Introduction
Recent advances in VLSI have made it possible to implement algorithm-structured chips as building blocks
for high-performance computing systems. Since sorting is one of the most fundamental computing problems,
it makes sense to endow general-purpose computer systems with a special-purpose parallel sorting ... | sorting networks;VLSI;special-purpose architectures;columnsort;hardware-algorithms |
357777 | Tracing the lineage of view data in a warehousing environment. | We consider the view data lineageproblem in a warehousing environment: For a given data item in a materialized warehouse view, we want to identify the set of source data items that produced the view item. We formally define the lineage problem, develop lineage tracing algorithms for relational views with aggregation, a... | Introduction
In a data warehousing system, materialized views over source data are defined, computed, and
stored in the warehouse to answer queries about the source data (which may be stored in distributed
and legacy systems) in an integrated and efficient way [Wid95]. Typically, on-line analytical
processing and minin... | lineage;materialized views;data warehouse;derviation |
358017 | A method for obtaining digital signatures and public-key cryptosystems. | An encryption method is presented with the novel property that publicly revealing an encryption key does not thereby reveal the corresponding decryption key. This has two important consequences: Couriers or other secure means are not needed to transmit keys, since a message can be enciphered using an encryption key pu... | Introduction
The era of "electronic mail" [10] may soon be upon us; we must ensure that two
important properties of the current "paper mail" system are preserved: (a) messages
are private, and (b) messages can be signed . We demonstrate in this paper how to
build these capabilities into an electronic mail system.
At th... | electronic funds transfer;privacy;digital signatures;public-key cryptosystems;cryptography;electronic mail;factorization;authentication;prime number;security;message-passing |
358684 | Efficient Address Generation for Affine Subscripts in Data-Parallel Programs. | Address generation for compiling programs, written in HPF, to executable SPMD code is an important and necessary phase in a parallelizing compiler. This paper presents an efficient compilation technique to generate the local memory access sequences for block-cyclically distributed array references with affine subscript... | Introduction
Generally speaking, data-parallel languages support
three regular data distributions: block, cyclic, and
block-cyclic data distributions. The block distribution
is to distribute contiguous array elements evenly
onto processors. The cyclic distribution is to distribute
each array element onto processors one... | affine subscripts;data-parallel languages;data distribution;address generation;multiple induction variables MIVs;distributed-memory multicomputers;single program multiple data SPMD |
358700 | Solving Fundamental Problems on Sparse-Meshes. | AbstractA sparse-mesh, which has PUs on the diagonal of a two-dimensional grid only, is a cost effective distributed memory machine. Variants of this machine have been considered before, but none are as simple and pure as a sparse-mesh. Various fundamental problems (routing, sorting, list ranking) are analyzed, proving... | Introduction
On ordinary two-dimensional meshes we must accept that, due to their small
bisection width, for most problems the maximum achievable speed-up with n 2
processing units (PUs) is only \Theta(n). On the other hand, networks such as hypercubes
impose increasing conditions on the interconnection modules with in... | routing;theory of parallel computation;algorithms;meshes;sorting;networks;list-ranking |
358939 | Data prefetch mechanisms. | The expanding gap between microprocessor and DRAM performance has necessitated the use of increasingly aggressive techniques designed to reduce or hide the latency of main memory access. Although large cache hierarchies have proven to be effective in reducing this latency for the most frequently used data, it is still ... | Introduction
By any metric, microprocessor performance has increased at a dramatic rate over the past decade.
This trend has been sustained by continued architectural innovations and advances in
microprocessor fabrication technology. In contrast, main memory dynamic RAM (DRAM)
performance has increased at a much more l... | prefetching;memory latency |
359194 | Dynamically Relaxed Block Incomplete Factorizations for Solving Two- and Three-Dimensional Problems. | To efficiently solve second-order discrete elliptic PDEs by Krylov subspace-like methods, one needs to use some robust preconditioning techniques. Relaxed incomplete factorizations (RILU) are powerful candidates.\ Unfortunately, their efficiency critically depends on the choice of the relaxation parameter $\omega$ whos... | Introduction
. As model problem, we take the following self-adjoint second
order elliptic PDE
in\Omega with suitable boundary conditions on
where\Omega denotes the unit square (2D case) or cube (3D case); the coefficients p, q
and r are positive and bounded while t is nonnegative and bounded. The differential
operator ... | large sparse linear systems;preconditioned conjugate gradient;incomplete factorizations;diagonal relaxation;discretized partial differential equations |
359199 | The Finite Mass Method. | The finite mass method, a new Lagrangian method for the numerical simulation of gas flows, is presented and analyzed. In contrast to the finite volume and the finite element method, the finite mass method is founded on a discretization of mass, not of space. Mass is subdivided into small mass packets of finite extensio... | Introduction
. Fluid mechanics is usually stated in terms of conservation
laws that link the change of a quantity like mass or momentum inside a given volume
to a flux of this quantity across the boundary of the volume. The finite volume
method is directly based on this formulation. Space is subdivided into little cell... | finite mass method;gridless discretizations;compressible fluids |
359222 | Discrete Kinetic Schemes for Multidimensional Systems of Conservation Laws. | We present here some numerical schemes for general multidimensional systems of conservation laws based on a class of discrete kinetic approximations, which includes the relaxation schemes by S. Jin and Z. Xin. These schemes have a simple formulation even in the multidimensional case and do not need the solution of the... | Introduction
. In this paper we present a new class of numerical schemes
based on a discrete kinetic approximation for multidimensional hyperbolic systems of
conservation laws. Consider a weak solution u
K to the Cauchy
problem
where the system is hyperbolic (symmetrizable) and the flux functions A d are locally
Lipsch... | conservation laws;hyperbolic systems;kinetic schemes;BGK models;numerical convergence |
359822 | An architecture for more realistic conversational systems. | In this paper, we describe an architecture for conversational systems that enables human-like performance along several important dimensions. First, interpretation is incremental, multi-level, and involves both general and task- and domain-specific knowledge. Second, generation is also incremental, proceeds in parallel... | INTRODUCTION
Our goal is to design and build systems that approach
human performance in conversational interaction. We limit
our study to practical dialogues: dialogues in which the conversants
are cooperatively pursuing specific goals or tasks.
Applications involving practical dialogues include planning
(e.g. designin... | architectures for intelligent;cooperative;distributed;conversational systems;multimodal interfaces |
360091 | Separation of Transparent Layers using Focus. | Consider situations where the depth at each point in the scene is multi-valued, due to the presence of a virtual image semi-reflected by a transparent surface. The semi-reflected image is linearly superimposed on the image of an object that is behind the transparent surface. A novel approach is proposed for the separat... | Introduction
The situation in which several (typically two) linearly superimposed contributions exist is often
encountered in real-world scenes. For example [12, 20], looking out of a car (or room) window,
we see both the outside world (termed real object [35, 36, 41, 42, 43, 45]), and a semi-reflection
of the objects ... | blur estimation;semireflections;enhancement;optical sectioning;blind deconvolution;depth from focus;inverse problems;signal separation;image reconstruction and recovery;decorrelation |
360328 | The effect of reconfigurable units in superscalar processors. | This paper describes OneChip, a third generation reconfigurable processor architecture that integrates a Reconfigurable Functional Unit (RFU) into a superscalar Reduced Instruction Set Computer (RISC) processor's pipeline. The architecture allows dynamic scheduling and dynamic reconfiguration. It also provides support ... | INTRODUCTION
Recently, the idea of using reconfigurable resources along
with a conventional processor has led to research in the area
Permission to make digital or hard copies of all or part of this work for
personal or classroom use is granted without fee provided that copies are
not made or distributed for profit or ... | reconfigurable processors;onechip;superscalar processors |
360393 | Validation of an Augmented Lagrangian Algorithm with a Gauss-Newton Hessian Approximation Using a Set of Hard-Spheres Problems. | An Augmented Lagrangian algorithm that uses Gauss-Newton approximations of the Hessian at each inner iteration is introduced and tested using a family of Hard-Spheres problems. The Gauss-Newton model convexifies the quadratic approximations of the Augmented Lagrangian function thus increasing the efficiency of the iter... | Introduction
In recent years we have been involved with the development of algorithms based
on sequential quadratic programming [11] and inexact restoration [16, 18] for minimization
problems with nonlinear equality constraints and bounded variables.
The validation of these algorithms require their comparison with well... | numerical methods;augmented Lagrangians;nonlinear programming |
360547 | Selecting Examples for Partial Memory Learning. | This paper describes a method for selecting training examples for a partial memory learning system. The method selects extreme examples that lie at the boundaries of concept descriptions and uses these examples with new training examples to induce new concept descriptions. Forgetting mechanisms also may be active to re... | Introduction
Partial memory learners are on-line systems that select and maintain a portion of
the past training examples, which they use together with new examples in subsequent
training episodes. Such systems can learn by memorizing selected new facts,
or by using selected facts to improve the current concept descrip... | on-line concept learning;partial memory models;concept drift |
360834 | Diamond Quorum Consensus for High Capacity and Efficiency in a Replicated Database System. | Many quorum consensus protocols have been proposed for the management of replicated data in a distributed environment. The advantages of a replicated database system over a non-replicated one include high availability and low response time. We note further that the multiple sites can act as multiple agents so that at a... | Introduction
A replicated database system is built in a distributed environment with multiple
sites, in which copies of data are stored at multiple sites. The main motivations of a
replicated database are to improve the reliability and performance. By storing data
at multiple sites, the database system can continue to ... | fault-tolerant computing;quorum consensus;mutual exclusion;distributed systems;replicated database systems |
361028 | Optimizing static calendar queues. | The calendar queue is an important implementation of a priority queue that is particularly useful in discrete event simulators. We investigate the performance of the static calendar queue that maintains N active events. The main contribution of this article is to prove that, under reasonable assumptions and with the pr... | INTRODUCTION
The calendar queue data structure, as described by Brown [Brown 1988], is an
important implementation of a priority queue that is useful as the event queue in
a discrete event simulator. At any time in a discrete event simulator there are
active events, where each event e has an associated event time t(e) ... | priority queue;optimization;calendar queue;discrete event simulation;data structures;algorithm analysis;markov chain |
361168 | Critical Motions for Auto-Calibration When Some Intrinsic Parameters Can Vary. | Auto-calibration is the recovery of the full camera geometry and Euclidean scene structure from several images of an unknown 3D scene, using rigidity constraints and partial knowledge of the camera intrinsic parameters. It fails for certain special classes of camera motion. This paper derives necessary and sufficient c... | Introduction
One of the core problems in computer vision is the recovery of 3D scene
structure and camera motion from a set of images. However, for certain
con-gurations there are inherent ambiguities. This kind of problem
was already studied in optics in the early 19th century, for example,
by Vieth in 1818 and Muller... | critical motions;absolute conic;calibration;structure and motion;projective geometry;auto-calibration;3D reconstruction |
361263 | Tolerance to Multiple Transient Faults for Aperiodic Tasks in Hard Real-Time Systems. | AbstractReal-time systems are being increasingly used in several applications which are time-critical in nature. Fault tolerance is an essential requirement of such systems, due to the catastrophic consequences of not tolerating faults. In this paper, we study a scheme that guarantees the timely recovery from multiple ... | Introduction
The interest in embedded systems has been growing steadily in the recent past, specially those
ples include autopilot systems, satellite and launch vehicle control, as well as robots, whether in
collaborating teams or not. For some of these systems, termed hard real-time systems (HRTSs), the
consequences o... | real-time scheduling;fault-tolerant schedules;fault recovery;earliest-deadline first |
361273 | On Load Balancing in Multicomputer/Distributed Systems Equipped with Circuit or Cut-Through Switching Capability. | AbstractFor multicomputer or distributed systems that use circuit switching, wormhole routing, or virtual cut-through (the last two are collectively called the cut-through switching), the communication overhead and the message delivery time depend largely upon link contention rather than upon the distance between the s... | Introduction
In multicomputer or distributed systems, dynamic creation/deletion of data and/or files may
temporarily overload some nodes'/sites' storage space while leaving some others' underloaded. Since
storage resources at a node/site are usually limited, uneven data/file distribution may result in
inefficient use o... | minimax flow problem;overloaded/underloaded nodes;load balancing;excess/deficit load;link traffic |
361502 | An Implementation of Constructive Synchronous Programs in POLIS. | Design tools for embedded reactive systems commonly use a model of computation that employs both synchronous and asynchronous communication styles. We form a junction between these two with an implementation of synchronous languages and circuits (Esterel) on asynchronous networks (POLIS). We implement fact propagation,... | Introduction
Our purpose is to reduce the gap between two distinct models of concurrency that are fundamental
in the embedded systems framework, the synchronous and asynchronous models, with
application to systems written in the Esterel synchronous programming language and implemented
in the POLIS system developed at U... | embedded systems;finite state machines;synchronous programming;asynchronous networks |
363459 | Wavelet and Fourier Methods for Solving the Sideways Heat Equation. | We consider an inverse heat conduction problem, the sideways heat equation, which is a model of a problem, where one wants to determine the temperature on both sides of a thick wall, but where one side is inaccessible to measurements. Mathematically it is formulated as a Cauchy problem for the heat equation in a quart... | Introduction
In many industrial applications one wishes to determine the temperature
on the surface of a body, where the surface itself is inaccessible for measurements
[1]. It may also be the case that locating a measurement device
(e.g. a thermocouple) on the surface would disturb the measurements so
that an incorrec... | cauchy problem;ill-posed;heat conduction;wavelet;inverse problem;fourier analysis |
363462 | Accuracy of Decoupled Implicit Integration Formulas. | Dynamical systems can often be decomposed into loosely coupled subsystems. The system of ordinary differential equations (ODEs) modelling such a problem can then be partitioned corresponding to the subsystems, and the loose couplings can be exploited by special integration methods to solve the problem using a parallel ... | Introduction
. The numerical solution of stiff systems of ordinary differential
equations (ODEs) requires implicit discretization formulas. The implicit algebraic
problems are usually solved by a Newton-type iteration method which involves the
solution of systems of linear equations that often turn out to be sparse. At... | parallel numerical integration;absolute stability;multirate formulas;backward differentiation formulas;euler's implicit formula;partitioned systems |
363956 | Theory of dependence values. | A new model to evaluate dependencies in data mining problems is presented and discussed. The well-known concept of the association rule is replaced by the new definition of dependence value, which is a single real number uniquely associated with a given itemset. Knowledge of dependence values is sufficient to describe ... | INTRODUCTION
A well known problem in data mining is the search for association rules, a powerful
and intuitive conceptual tool to represent the phenomena that are recurrent in a
data set. A number of interesting solutions of that problem has been proposed in
the last five years together with as many powerful algorithms... | entropy;dependence rules;variables independence;association rules |
364001 | Discontinuous enrichment in finite elements with a partition of unity method. | We present an approximate analytical method to evaluate efficiently and accurately the call blocking probabilities in wavelength routing networks with multiple classes of calls. The model is fairly general and allows each source-destination pair to service calls of different classes, with each call occupying one wavele... | Introduction
The modeling of evolving discontinuities with the finite element method is
cumbersome due to the need to update the mesh topology to match the
geometry of the discontinuity. In this paper, we present a technique to model
discontinuities in the finite element framework in a general fashion. The
essential fe... | partition-of-unity;fracture;discontinuous enrichment |
364268 | Recognizing Action Units for Facial Expression Analysis. | AbstractMost automatic expression analysis systems attempt to recognize a small set of prototypic expressions, such as happiness, anger, surprise, and fear. Such prototypic expressions, however, occur rather infrequently. Human emotions and intentions are more often communicated by changes in one or a few discrete faci... | Introduction
Recently facial expression analysis has attracted attention in the computer vision literature [3, 5, 6, 9,
11, 13, 17, 19]. Most automatic expression analysis systems attempt to recognize a small set of prototypic
expressions (i.e. joy, surprise, anger, sadness, fear, and disgust) [11, 17]. In everyday lif... | neural network;facial expression analysis;action units;multistate face and facial component models;computer vision;facial action coding system;AU combinations |
365027 | Scale effects in steering law tasks. | Interaction tasks on a computer screen can technically be scaled to a much larger or much smaller sized input control area by adjusting the input device's control gain or the control-display (C-D) ratio. However, human performance as a function of movement scale is not a well concluded topic. This study introduces a ne... | INTRODUCTION
This research addresses the following questions: Can we successfully
accomplish the two steering tasks in Figure 1 in the
same amount of time? Can a large input device be substituted
with a small one without significantly impacting user
performance? Does size matter to input control quality? Can
a small-si... | input device;movement scale;C-D ratio;joints;elbow;motor control;finger;control gain;steering law;wrist;device size |
365035 | Empirically validated web page design metrics. | A quantitative analysis of a large collection of expert-rated web sites reveals that page-level metrics can accurately predict if a site will be highly rated. The analysis also provides empirical evidence that important metrics, including page composition, page formatting, and overall page characteristics, differ amon... | INTRODUCTION
There is currently much debate about what constitutes good
web site design [19, 21]. Many detailed usability guidelines
have been developed for both general user interfaces
and for web page design [6, 16]. However, designers have
historically experienced difficulties following design guidelines
[2, 7, 15, ... | World Wide Web;automated usability evaluation;empirical studies;web site design |
365334 | Optimal Reward-Based Scheduling for Periodic Real-Time Tasks. | AbstractReward-based scheduling refers to the problem in which there is a reward associated with the execution of a task. In our framework, each real-time task comprises a mandatory and an optional part. The mandatory part must complete before the task's deadline, while a nondecreasing reward function is associated wit... | Introduction
In a real-time system each task must complete and produce correct output by the specified deadline.
However, if the system is overloaded it is not possible to meet each deadline. In the past, several
techniques have been introduced by the research community regarding the appropriate strategy to use
in over... | deadline scheduling;real-time systems;reward maximization;periodic task scheduling;imprecise computation |
365430 | Optimal covering tours with turn costs. | We give the first algorithmic study of a class of covering tour problems related to the geometric Traveling Salesman Problem: Find a polygonal tour for a cutter so that it sweeps out a specified region (pocket), in order to minimize a cost that depends not only on the length of the tour but also on the number of turns.... | Introduction
An important algorithmic problem in manufacturing is to
compute effective paths and tours for covering ("milling")
a given region ("pocket") with a cutting tool: Find a path
or tour along which to move a prescribed cutter in order
that the sweep of the cutter (exactly) covers the re-
gion, removing all of ... | lawn mowing;approximation algorithms;manufacturing;traveling salesman problem TSP;NP-completeness;NC machining;turn costs;milling;covering;m-guillotine subdivisions;polynomial-time approximation scheme PTAS |
365707 | Resolving Motion Correspondence for Densely Moving Points. | AbstractThis paper studies the motion correspondence problem for which a diversity of qualitative and statistical solutions exist. We concentrate on qualitative modeling, especially in situations where assignment conflicts arise either because multiple features compete for one detected point or because multiple detecte... | Introduction
Motion correspondence has a number of applications in computer vision, ranging from motion analysis,
object tracking and surveillance to optical flow and structure from motion [11], [24], [25], [26]. Motion
# The authors are with the Department of Mediamatics, Faculty of Information Technology and Systems,... | target tracking;algorithms;motion correspondence;feature point tracking |
365735 | A framework for symmetric band reduction. | We develop an algorithmic framework for reducing the bandwidth of symmetric matrices via orthogonal similarity transformations. This framework includes the reduction of full matrices to banded or tridiagonal form and the reduction of banded matrices to narrower banded or tridiagonal form, possibly in multiple steps. Ou... | INTRODUCTION
Reduction to tridiagonal form is a major step in eigenvalue computations for symmetric
matrices. If the matrix is full, the conventional Householder tridiagonal-
ization approach (e.g., [Golub and Van Loan 1989]) or a block variant thereof
[Dongarra et al. 1989] is usually considered the method of choice.
... | blocked Householder transformations;symmetric matrices;tridiagonalization |
365880 | Exact Analysis of Exact Change. | We introduce the k-payment problem: given a total budget of N units, the problem is to represent this budget as a set of coins, so that any k exact payments of total value at most N can be made using k disjoint subsets of the coins. The goal is to minimize the number of coins for any given N and k, while allowing the ... | Introduction
Consider the following everyday scenario. You want to withdraw N units of money from your
bank. The teller asks you "how would you like to have it?" Let us assume that you need to
have "exact change," i.e., given any payment request P - N , you should be able to choose a
subset of your "coins" whose sum is... | coin allocation;change-making;exact change;electronic cash;k-payment problem |
365883 | Graph Searching and Interval Completion. | In the early studies on graph searching a graph was considered as a system of tunnels in which a fast and clever fugitive is hidden. The "classical" search problem is to find a search plan using the minimal number of searchers. In this paper, we consider a new criterion of optimization, namely, the search cost. First... | Introduction
Search problems on graphs attract the attention of researchers from different
fields of Mathematics and Computer Science for a variety of reasons. In the
first place, this is the resemblance of graph searching to certain pebble games
[18] that model sequential computation. The second motivation of the inte... | interval graph completion;graph searching;linear layout;search cost;profile;cograph;vertex separation |
365895 | Probabilistic Models of Appearance for 3-D Object Recognition. | We describe how to model the appearance of a 3-D object using multiple views, learn such a model from training images, and use the model for object recognition. The model uses probability distributions to describe the range of possible variation in the object's appearance. These distributions are organized on two level... | Introduction
Object recognition requires a model of appearance that can be matched to new images. In
this paper, a new model representation will be described that can be derived automatically
from a sample of images of the object. The representation models an object by a probability
distribution that describes the rang... | object recognition;model indexing;appearance representation;visual learning;model-based vision;clustering |
365936 | On the Fourier Properties of Discontinuous Motion. | Retinal image motion and optical flow as its approximation are fundamental concepts in the field of vision, perceptual and computational. However, the computation of optical flow remains a challenging problem as image motion includes discontinuities and multiple values mostly due to scene geometry, surface translucency... | Introduction
A fundamental problem in processing sequences of
images is the computation of optical
ow, an approximation
to image motion dened as the projection
of velocities of 3D surface points onto the
imaging plane of a visual sensor. The importance
of motion in visual processing cannot be under-
stated: in particul... | image motion;aperture problem;occlusion;optical flow;non-Fourier motion |
365972 | Logic Based Abstractions of Real-Time Systems. | When verifying concurrent systems described by transition systems, state explosion is one of the most serious problems. If quantitative temporal information (expressed by clock ticks) is considered, state explosion is even more serious. We present a notion of abstraction of transition systems, where the abstraction is ... | Introduction
In this paper we address the problem of verifying systems in which time plays
a fundamental role for a correct behaviour. We refer to the Algebra of Timed
Processes (ATP) [22] as a formalism able both to model time dependent systems
and to prove their properties. ATP is an extension of traditional process ... | temporal logic;ATP;state explosion |
367881 | Empirical Studies of a Prediction Model for Regression Test Selection. | AbstractRegression testing is an important activity that can account for a large proportion of the cost of software maintenance. One approach to reducing the cost of regression testing is to employ a selective regression testing technique that 1) chooses a subset of a test suite that was used to test the software befor... | Introduction
Regression testing is an important activity that can account for a large proportion of the cost of software
maintenance [5, 17]. Regression testing is performed on modified software to provide confidence that the
software behaves correctly and that modifications have not adversely impacted the software's q... | regression test selection;software maintenance;selective retest;regression testing |
368139 | A flexible message passing mechanism for objective VHDL. | When defining an object-oriented extension to VHDL, the necessary message passing is one of the most complex issues and has a large impact on the whole language. This paper identifies the requirements for message passing suited to model hardware and classifies different approaches. To allow abstract communication and r... | Introduction
A (hardware) system can be described in the object-oriented
fashion as a set of interacting or communicating
(concurrent) objects. In consequence to encapsulation the
objects tend to be relatively autonomous and only loosely
coupled with their environment [13]. Further, an object
should contain most of the... | message passing;communication;object-oriented hardware modelling |
368247 | Optimal temporal partitioning and synthesis for reconfigurable architectures. | We develop a 0-1 non-linear programming (NLP) model for combined temporal partitioning and high-level synthesis from behavioral specifications destined to be implemented on reconfigurable processors. We present tight linearizations of the NLP model. We present effective variable selection heuristics for a branch and bo... | Introduction
Dynamically reconfigurable processors are becoming
increasingly viable with the advent of modern field-programmable
devices, especially the SRAM-based
FPGAs. Execution of hardware computations using
reconfigurable processors necessitates a temporal partitioning
of the specification. Temporal partitioning
d... | temporal partitioning;non-linear programming;integer linear programming;synthesis |
368299 | Fast sequential circuit test generation using high-level and gate-level techniques. | A new approach for sequential circuit test generation is proposed that combines software testing based techniques at the high level with test enhancement techniques at the gate level. Several sequences are derived to ensure 100% coverage of all statements in a high-level VHDL description, or to maximize coverage of pat... | Introduction
Most recent work in the area of sequential circuit test
generation has focused on the gate level and has been
targeted at single stuck-at faults. Both deterministic
fault-oriented and simulation-based approaches have
been used e#ectively, although execution times are often
long. The key factor limiting the... | automatic test generation;test sequence compaction;sequential circuits;software testing |
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