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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273577 | Numerical Condition of Discrete Wavelet Transforms. | The recursive algorithm of a (fast) discrete wavelet transform, as well as its generalizations, can be described as repeated applications of block-Toeplitz operators or, in the case of periodized wavelets, multiplications by block circulant matrices. Singular values of a block circulant matrix are the singular values o... | Introduction
. Orthogonality is a very strong property. It might exclude
other useful properties like, for example, symmetry in the case of compactly supported
wavelets [6, 7]. Consequently, in many applications biorthogonal wavelets have
been used rather than the orthogonal ones. Stability of such bases has been studi... | block-Toeplitz operators;translational bases;biorthogonal wavelets;numerical condition;block circulant matrices |
273582 | Robust Solutions to Least-Squares Problems with Uncertain Data. | We consider least-squares problems where the coefficient matrices A,b are unknown but bounded. We minimize the worst-case residual error using (convex) second-order cone programming, yielding an algorithm with complexity similar to one singular value decomposition of A. The method can be interpreted as a Tikhonov regul... | Introduction
. Consider the problem of finding a solution x to an overdetermined
set of equations Ax ' b, where the data matrices A 2 R n\Thetam , b 2 R n are given.
The Least Squares (LS) fit minimizes the residual k\Deltabk subject to resulting
in a consistent linear model of the form \Deltab) that is closest to the ... | uncertainty;robustness;ill-conditioned problem;regularization;least-squares problems;second-order cone programming;robust identification;robust interpolation;semidefinite programming |
273585 | Locality of Reference in LU Decomposition with Partial Pivoting. | This paper presents a new partitioned algorithm for LU decomposition with partial pivoting. The new algorithm, called the recursively partitioned algorithm, is based on a recursive partitioning of the matrix. The paper analyzes the locality of reference in the new algorithm and the locality of reference in a known and ... | Introduction
. Algorithms that partition dense matrices into blocks and operate
on entire blocks as much as possible are key to obtaining high performance
on computers with hierarchical memory systems. Partitioning a matrix into blocks
creates temporal locality of reference in the algorithm and reduces the number of
wo... | LU factorization;gaussian elimination;cache misses;partial pivoting;locality of reference |
273592 | A Survey of Combinatorial Gray Codes. | The term combinatorial Gray code was introduced in 1980 to refer to any method for generating combinatorial objects so that successive objects differ in some prespecified, small way. This notion generalizes the classical binary reflected Gray code scheme for listing n-bit binary numbers so that successive numbers diffe... | Introduction
One of the earliest problems addressed in the area of combinatorial algorithms was that of
efficiently generating items in a particular combinatorial class in such a way that each item is
generated exactly once. Many practical problems require for their solution the sampling of a
random object from a combi... | cayley graphs;hamilton cycles;permutations;combinations;linear extensions;vertex-transitive graphs;de Bruijn sequences;boolean lattice;set partitions;acyclic orientations;gray codes;restricted growth functions;catalan families;integer partitions;necklaces;compositions;binary strings |
273702 | Fully Discrete Finite Element Analysis of Multiphase Flow in Groundwater Hydrology. | This paper deals with the development and analysis of a fully discrete finite element method for a nonlinear differential system for describing an air-water system in groundwater hydrology. The nonlinear system is written in a fractional flow formulation, i.e., in terms of a saturation and a global pressure. The satura... | Introduction
. In this paper we develop and analyze a fully-discrete finite element
procedure for solving the flow equations for an air-water system in groundwater
hydrology,
@t
kk rff
porous medium, OE and k are the porosity and absolute
permeability of the porous system, ae ff , s ff , p ff , u ff , and - ff are the ... | error estimate;air-water system;finite element;porous media;numerical experiments;mixed method;compressible flow;time discretization |
273705 | Convergence of a Multigrid Method for Elliptic Equations with Highly Oscillatory Coefficients. | Standard multigrid methods are not so effective for equations with highly oscillatory coefficients. New coarse grid operators based on homogenized operators are introduced to restore the fast convergence rate of multigrid methods. Finite difference approximations are used for the discretization of the equations. Conver... | Introduction
Consider the multigrid method arising from the finite difference approximations to elliptic
equations with highly oscillatory coefficients of the following type
@
a ffl
where a ffl
strictly positive, continuous and 1-periodic in
each component of y. Also, the operator L ffl is uniformly elliptic. That is, ... | convergence;oscillation;homogenization theory;elliptic equation;finite difference;multigrid method |
273720 | Multidimensional Interpolatory Subdivision Schemes. | This paper presents a general construction of multidimensional interpolatory subdivision schemes. In particular, we provide a concrete method for the construction of bivariate interpolatory subdivision schemes of increasing smoothness by finding an appropriate mask to convolve with the mask of a three-direction box spl... | iii. The function ' is in some H-older class C ff for suitable ff.
The function ' is fundamental, if i holds, and it is refinable, if ii holds. The sequence h is
called the refinement mask of the function '.
In that sense the paper is a continuation of [25] where we considered compactly supported
fundamental solutions ... | subdivision schemes;box splines;wavelets;interpolatory subdivision schemes;interpolation |
273734 | Quasi-Optimal Schwarz Methods for the Conforming Spectral Element Discretization. | The spectral element method is used to discretize self-adjoint elliptic equations in three-dimensional domains. The domain is decomposed into hexahedral elements, and in each of the elements the discretization space is the set of polynomials of degree N in each variable. A conforming Galerkin formulation is used, the c... | Introduction
. In the past decade, many preconditioners have been developed
for the large systems of linear equations arising from the finite element discretization
of elliptic self-adjoint partial differential equations; see e.g. [6], [14], [27]. A specially
challenging problem is the design of preconditioners for thr... | schwarz methods;preconditioned conjugate gradients;iterative substructuring;domain decomposition;spectral element method |
273914 | Theory of neuromata. | A finite automatonthe so-called neuromaton, realized by a finite discrete recurrent neural network, working in parallel computation mode, is considered. Both the size of neuromata (i.e., the number of neurons) and their descriptional complexity (i.e., the number of bits in the neuromaton representation) are studied. It... | Introduction
Neural networks [7] are models of computation motivated by our ideas about brain
functioning. Both their computational power and their efficiency have been traditionally
investigated [4, 14, 15, 19, 21] within the framework of computer science.
One less commonly studied task which we will be addressing is ... | hopfield networks;finite neural networks;regular expressions;descriptional complexity;emptiness problem;string acceptors |
274068 | Online Learning versus Offline Learning. | We present an off-line variant of the mistake-bound model of learning. This is an intermediate model between the on-line learning model (Littlestone, 1988, Littlestone, 1989) and the self-directed learning model (Goldman, Rivest Schapire, 1993, Goldman & Sloan, 1994). Just like in the other two models, a learner in the... | Introduction
The mistake-bound model of learning, introduced by Littlestone [L88, L89], has attracted a considerable
amount of attention (e.g., [L88, L89, LW89, B90a, B90b, M91, CM92, HLL92, GRS93, GS94])
and is recognized as one of the central models of computational learning theory. Basically it models
a process of i... | mistake-bound;On-Line Learning;rank of trees |
274165 | Factorial Hidden Markov Models. | Hidden Markov models (HMMs) have proven to be one of the most widely used tools for learning probabilistic models of time series data. In an HMM, information about the past is conveyed through a single discrete variablethe hidden state. We discuss a generalization of HMMs in which this state is factored into multiple s... | Introduction
Due to its flexibility and to the simplicity and efficiency of its parameter estimation
algorithm, the hidden Markov model (HMM) has emerged as one of the basic statistical
tools for modeling discrete time series, finding widespread application in the
areas of speech recognition (Rabiner & Juang, 1986) and... | mean field theory;bayesian networks;hidden markov models;graphical models;time series;EM algorithm |
274791 | Approximate graph coloring by semidefinite programming. | We consider the problem of coloring k-colorable graphs with the fewest possible colors. We present a randomized polynomial time algorithm that colors a 3-colorable graph on n vertices with min{O(&Dgr;1/3 log1/2 &Dgr; log n), O(n1/4 log1/2 n)} colors where &Dgr; is the maximum degree of any vertex. Besides giving the be... | Introduction
A legal vertex coloring of a graph G(V; E) is an assignment of colors to its vertices such that no
two adjacent vertices receive the same color. Equivalently, a legal coloring of G by k colors is a
partition of its vertices into k independent sets. The minimum number of colors needed for such
a coloring is... | approximation algorithms;randomized algorithms;NP-completeness;graph coloring;chromatic number |
275325 | Compiler blockability of dense matrix factorizations. | The goal of the LAPACK project is to provide efficient and portable software for dense numerical linear algebra computations. By recasting many of the fundamental dense matrix computations in terms of calls to an efficient implementation of the BLAS (Basic Linear Algebra Subprograms), the LAPACK project has, in large p... | Introduction
The processing power of microprocessors and supercomputers has increased dramatically and continues
to do so. At the same time, the demand on the memory system of a computer is to increase
dramatically in size. Due to cost restrictions, typical workstations cannot use memory chips that
have the latency and... | LAPACK;LU decomposition;QR decomposition;BLAS;cholesky decomposition;cache optimization |
275339 | Component Based Design of Multitolerant Systems. | AbstractThe concept of multitolerance abstracts problems in system dependability and provides a basis for improved design of dependable systems. In the abstraction, each source of undependability in the system is represented as a class of faults, and the corresponding ability of the system to deal with that undependabi... | Introduction
Dependability is an increasingly relevant system-level requirement that encompasses the ability of
a system to deliver its service in a desirable manner, in spite of the occurrence of faults, security
intrusions, safety hazards, configuration changes, load variations, etc. Achieving this ability is
difficu... | formal methods;stepwise design;correctors;graceful degradation;dependability;compositional design;fault-tolerance;detectors;interference-freedom |
275347 | Generalized Queries on Probabilistic Context-Free Grammars. | AbstractProbabilistic context-free grammars (PCFGs) provide a simple way to represent a particular class of distributions over sentences in a context-free language. Efficient parsing algorithms for answering particular queries about a PCFG (i.e., calculating the probability of a given sentence, or finding the most like... | Introduction
pattern-recognition problems start from observations generated by some structured
stochastic process. Probabilistic context-free grammars (PCFGs) [1], [2]
have provided a useful method for modeling uncertainty in a wide range of structures,
including natural languages [2], programming languages [3], images... | probabilistic context-free grammars;bayesian networks |
275840 | Efficient Sparse LU Factorization with Partial Pivoting on Distributed Memory Architectures. | AbstractA sparse LU factorization based on Gaussian elimination with partial pivoting (GEPP) is important to many scientific applications, but it is still an open problem to develop a high performance GEPP code on distributed memory machines. The main difficulty is that partial pivoting operations dynamically change co... | Currently with the Computer Science Department, University of Illinois at Urbana-Champaign.
pivoting operations interchange rows based on the numerical values of matrix elements during the
elimination process, it is impossible to predict the precise structures of L and U factors without
actually performing the numerica... | dense structures;Sparse LU factorization;gaussian elimination with partial pivoting;irregular parallelism;asynchronous computation scheduling |
275845 | Strong Interaction Fairness Via Randomization. | AbstractWe present MULTI, a symmetric, distributed, randomized algorithm that, with probability one, schedules multiparty interactions in a strongly fair manner. To our knowledge, MULTI is the first algorithm for strong interaction fairness to appear in the literature. Moreover, the expected time taken by MULTI to esta... | Introduction
A multiparty interaction is a set of I/O actions executed jointly by a number of processes, each of
which must be ready to execute its own action for any of the actions in the set to occur. An attempt
to participate in an interaction delays a process until all other participants are available. After
the ac... | multiparty interaction;weak interaction fairness;randomized algorithms;committee coordination;distributed algorithms;strong interaction fairness |
275853 | Scheduling Block-Cyclic Array Redistribution. | AbstractThis article is devoted to the run-time redistribution of one-dimensional arrays that are distributed in a block-cyclic fashion over a processor grid. While previous studies have concentrated on efficiently generating the communication messages to be exchanged by the processors involved in the redistribution, w... | Introduction
Run-time redistribution of arrays that are distributed in a block-cyclic fashion over a multidimensional
processor grid is a difficult problem that has recently received considerable attention. This
interest is motivated largely by the HPF [13] programming style, in which scientific applications
are decomp... | block-cyclic distribution;MPI;distributed arrays;scheduling;HPF;redistribution |
275931 | Timestep Acceleration of Waveform Relaxation. | Dynamic iteration methods for treating certain classes of linear systems of differential equations are considered. It is shown that the discretized Picard--Lindelf (waveform relaxation) iteration can be accelerated by solving the defect equations with a larger timestep, or by using a recursive procedure based on a succ... | Introduction
. Much of modern chemical and physical research relies on the numerical
solution of various wave equations. Since these problems are extremely demanding of both
storage and cpu-time, new numerical methods and fast algorithms are needed to make optimal
use of advanced computers. The dynamic iteration or wav... | multigrid methods;waveform relaxation;wave equation |
275958 | A Fast Iterative Algorithm for Elliptic Interface Problems. | A fast, second-order accurate iterative method is proposed for the elliptic equation \[ \grad\cdot(\beta(x,y) \grad u) =f(x,y) \] in a rectangular region $\Omega$ in two-space dimensions. We assume that there is an irregular interface across which the coefficient $\beta$, the solution u and its derivatives, and/or the ... | Introduction
. Consider the elliptic equation
r (fi(x;
2\Omega
Given BC on
in a rectangular
domain\Omega in two space dimensions. Within the region, suppose there
is an irregular interface \Gamma across which the coefficient fi is discontinuous. Referring to
Fig 1, we assume that fi(x; y) has a constant value in each s... | GMRES method;immersed interface method;discontinuous coefficients;elliptic equation;schur complement;preconditioning;cartesian grid |
275961 | Inner and Outer Iterations for the Chebyshev Algorithm. | We analyze the preconditioned Chebyshev iteration in which at each step the linear system involving the preconditioner is solved inexactly by an inner iteration. We allow the tolerance used in the inner iteration to decrease from one outer iteration to the next. When the tolerance converges to zero, the asymptotic con... | Introduction
The Chebyshev iterative algorithm [1] for solving linear systems of equations often requires
at each step the solution of a subproblem i.e. the solution of another linear system. We
assume that the subproblem is also solved iteratively by an "inner iteration". The term
"outer iteration" refers to a step of... | inexact iteration;iterative methods;inner iteration |
275988 | The Value Function of the Singular Quadratic Regulator Problem with Distributed Control Action. | We study the regularity properties of the value function of a quadratic regulator problem for a linear distributed parameter system with distributed control action. No definiteness assumption on the cost functional is assumed. We study the regularity in time of the value function and also the s... | Introduction
. In this paper we are concerned with a general class of finite
horizon linear quadratic optimal control problems for evolution equations with distributed
control and non-definite cost. More precisely, we consider the following
abstract differential equation over a finite interval [-; T
where A is the infi... | distributed systems;value function;quadratic regulator |
276242 | Two-Dimensional Periodicity in Rectangular Arrays. | String matching is rich with a variety of algorithmic tools. In contrast, multidimensional matching has had a rather sparse set of techniques. This paper presents a new algorithmic technique for two-dimensional matching: periodicity analysis. Its strength appears to lie in the fact that it is inherently two-dimensiona... | Introduction
String matching is a field rich with a variety of algorithmic ideas. The early string matching
algorithms were mostly based on constructing a pattern automaton and subsequently using it
to find all pattern appearances in a given text ([KMP-77, AC-75, BM-77]). Recently developed
algorithms [G-85, V-85, V-91... | string matching;witness;parallel algorithm;periodicity;sequential algorithm;two-dimensional |
276469 | Convergence Analysis of Pseudo-Transient Continuation. | Pseudo-transient continuation ($\Psi$tc) is a well-known and physically motivated technique for computation of steady state solutions of time-dependent partial differential equations. Standard globalization strategies such as line search or trust region methods often stagnate at local minima. \ptc succeeds in many of t... | Introduction
. Pseudo-transient continuation (\Psitc) is a method for computation of steady-state
solutions of partial differential equations. We shall interpret the method in the context of
a method-of-lines solution, in which the equation is discretized in space and the resulting finite
dimensional system of ordinary... | pseudo-transient continuation;nonlinear equations;global convergence;steady state solutions |
276471 | Wavelet-Based Numerical Homogenization. | A numerical homogenization procedure for elliptic differential equations is presented. It is based on wavelet decompositions of discrete operators in fine and coarse scale components followed by the elimination of the fine scale contributions. If the operator is in divergence form, this is preserved by the homogeniza... | Introduction
In many applications the problem and solution exhibit a number of different scales.
In certain cases we are interested in finding the correct coarse-scale features of the
solution without resolving the finer scales. The fine-scale features may be of lesser
importance, or they may be prohibitively expensive... | wavelets;elliptic operators;homogenization |
276474 | Numerical Integrators that Preserve Symmetries and Reversing Symmetries. | We consider properties of flows, the relationships between them, and whether numerical integrators can be made to preserve these properties. This is done in the context of automorphisms and antiautomorphisms of a certain group generated by maps associated to vector fields. This new framework unifies several known const... | Introduction
Recently there has been a lot of interest in constructing numerical integration schemes
for ordinary differential equations (ODEs) in such a way that some qualitative geometrical
property of the solution of the ODE is exactly preserved. This has resulted in much
work on integration schemes that can preserv... | symmetries;automorphisms;numerical integrators |
276485 | Analysis of Algorithms Generalizing B-Spline Subdivision. | A new set of tools for verifying smoothness of surfaces generated by stationary subdivision algorithms is presented. The main challenge here is the verification of injectivity of the characteristic map. The tools are sufficiently versatile and easy to wield to allow, as an application, a full analysis of algorithms gen... | Introduction
The idea of generating smooth free-form surfaces of arbitrary topology by iterated mesh
refinement dates back to 1978, when two papers [CC78], [DS78] appeared back to back in
the same issue of Computer Aided Design. Named after their inventors, the Doo-Sabin
and the Catmull-Clark algorithm represent genera... | arbitrary topology;b-spline;doo-sabin algorithm;characteristic map;catmull-clark algorithm;subdivision |
276487 | Discrete Shocks for Finite Difference Approximations to Scalar Conservation Laws. | Numerical simulations often provide strong evidences for the existence and stability of discrete shocks for certain finite difference schemes approximating conservation laws. This paper presents a framework for converting such numerical observations to mathematical proofs. The framework is applicable to conservative s... | Introduction
In this paper, we provide a general framework for proving the existence and stability of continuous
discrete shock profiles for conservative finite difference schemes which approximate
scalar conservation laws
Research supported by ARPA/GNR grant N00014-92-J-1890.
We consider schemes of conservative form:
... | conservation law;weighted ENO;discrete shock |
276491 | A New Spectral Boundary Integral Collocation Method for Three-Dimensional Potential Problems. | In this work we propose and analyze a new global collocation method for classical second-kind boundary integral equations of potential theory on smooth simple closed surfaces $\Gamma \subset {\Bbb R}^3$. Under the assumption that $\Gamma$ is diffeomorphic to the unit sphere $\partial B$, the original equation is trans... | Introduction
In this work we present a new spectrally convergent collocation method for second-kind
boundary integral equations of potential theory. Our method is the result of a search
for a three-dimensional analogue of well-known discrete global Galerkin or "pseudospec-
tral" schemes for integral equations on planar... | fourier approximation;pseudospectral method;boundary integral equation;three-dimensional potential problems;collocation |
277067 | Incorporating speculative execution into scheduling of control-flow intensive behavioral descriptions. | Speculative execution refers to the execution of parts of a computation before the execution of the conditional operations that decide whether it needs to be executed. It has been shown to be a promising technique for eliminating performance bottlenecks imposed by control flow in hardware and software implementations a... | Introduction
Speculative execution refers to the execution of a part of a computation
before it is known if the control path to which it belongs
will be executed (for example, execution of the code after a branch
statement before the branch condition itself is evaluated). It has
been used to overcome, to some extent, t... | high-level synthesis;telecommunication |
277563 | Minimization of Communication Cost Through Caching in Mobile Environments. | AbstractUsers of mobile computers will soon have online access to a large number of databases via wireless networks. Because of limited bandwidth, wireless communication is more expensive than wire communication. In this paper, we present and analyze various static and dynamic data allocation methods. The objective is ... | Introduction
Users of mobile computers, such as palmtops, notebook computers and personal communication
systems, will soon have online access to a large number of databases via wireless networks. The
potential market for this activity is estimated to be billions of dollars annually, in access and
communication charges.... | probabilistic analysis;mobile computing;communication cost;wireless communication;dynamic data allocation;caching |
277606 | Concurrency Control and View Notification Algorithms for Collaborative Replicated Objects. | AbstractThis paper describes algorithms for implementing a high-level programming model for synchronous distributed groupware applications. In this model, several application data objects may be atomically updated, and these objects automatically maintain consistency with their replicas using an optimistic algorithm. C... | Introduction
Synchronous distributed groupware applications
are finding larger audiences and increased interest
with the popularity of the World Wide Web. Major
browsers include loosely integrated groupware applications
like chat and whiteboards. With browser functionality
extensible through programmability (Java
apple... | optimistic concurrency control;pessimistic views;optimistic views;groupware;replicated objects;model-view-controller programming paradigm |
277653 | Complete removal of redundant expressions. | Partial redundancy elimination (PRE), the most important component of global optimizers, generalizes the removal of common subexpressions and loop-invariant computations. Because existing PRE implementations are based on code motion, they fail to completely remove the redundancies. In fact, we observed that 73% of loop... | Introduction
Partial redundancy elimination (PRE) is a widely used and
effective optimization aimed at removing program statements
that are redundant due to recomputing previously
produced values [27]. PRE is attractive because by targeting
statements that are redundant only along some execution
paths, it subsumes and ... | speculative execution;demand-driven frequency data-flow analysis;control flow restructuring;partial redundancy elimination;profile-guided optimization |
277715 | An implementation of complete, asynchronous, distributed garbage collection. | Most existing reference-based distributed object systems include some kind of acyclic garbage collection, but fail to provide acceptable collection of cyclic garbage. Those that do provide such GC currently suffer from one or more problems: synchronous operation, the need for expensive global consensus or termination a... | Introduction
Automatic garbage collection is an important feature for
modern high-level languages. Although there is a lot of accumulated
experience in local garbage collection, distributed
programming still lacks effective cyclic garbage collection.
A local garbage collector should be correct and complete.
A distribut... | distributed object systems;storage management;garbage collection;reference tracking |
277725 | The implementation of the Cilk-5 multithreaded language. | The fifth release of the multithreaded language Cilk uses a provably good "work-stealing" scheduling algorithm similar to the first system, but the language has been completely redesigned and the runtime system completely reengineered. The efficiency of the new implementation was aided by a clear strategy that arose fr... | Introduction
Cilk is a multithreaded language for parallel programming
that generalizes the semantics of C by introducing linguistic
constructs for parallel control. The original Cilk-1 release
[3, 4, 18] featured a provably efficient, randomized, "work-
stealing" scheduler [3, 5], but the language was clumsy,
because ... | programming language;runtime system;multithreading;critical path;parallel computing |
277743 | Optimizing direct threaded code by selective inlining. | Achieving good performance in bytecoded language interpreters is difficult without sacrificing both simplicity and portability. This is due to the complexity of dynamic translation ("just-in-time compilation") of bytecodes into native code, which is the mechanism employed universally by high-performance interpreters.We... | Introduction
Bytecoded languages such as Smalltalk [Gol83], Caml
[Ler97] and Java [Arn96, Lin97] offer significant engineering
advantages over more conventional languages: higher
levels of abstraction, dynamic execution environments with
incremental debugging and code modification, compact representation
of executable ... | threaded code;bytecode interpretation;dynamic translation;inlining;just-in-time compilation |
277884 | Transient loss performance of a class of finite buffer queueing systems. | Performance-oriented studies typically rely on the assumption that the stochastic process modeling the phenomenon of interest is already in steady state. This assumption is, however, not valid if the life cycle of the phenomenon under study is not large enough, since usually a stochastic process cannot reach steady sta... | Introduction
For a queueing system with finite buffer, loss performance
is usually of great interest. One may want to know
the probability that loss of workload occurs, or the expected
workload loss ratio, due to buffer overflow. In the
existing literature, this issue is typically addressed under
the assumption that th... | stochastic modeling;transient loss performance;queueing systems |
277888 | Queueing-based analysis of broadcast optical networks. | We consider broadcast WDM networks operating with schedules that mask the transceiver tuning latency. We develop and analyze a queueing model of the network in order to obtain the queue-length distribution and the packet loss probability at the transmitting and receiving side of the nodes. The analysis is carried out a... | Introduction
It has long been recognized that Wavelength Division Multiplexing
(WDM) will be instrumental in bridging the gap
between the speed of electronics and the virtually unlimited
bandwidth available within the optical medium. The wave-length
domain adds a significant new degree of freedom to
network design, all... | markov modulated bernoulli process;discrete-time queueing networks;optical networks;wavelength division multiplexing |
277910 | Modeling set associative caches behavior for irregular computations. | While much work has been devoted to the study of cache behavior during the execution of codes with regular access patterns, little attention has been paid to irregular codes. An important portion of these codes are scientific applications that handle compressed sparse matrices. In this work a probabilistic model for th... | Introduction
Sparse matrices are in the kernel of many numerical appli-
cations. Their compressed storage [?], which permits both
operations and memory savings, generates irregular access
patterns. This fact reduces and makes hard to predict the
performance of the memory hierarchy. In this work a probabilistic
model fo... | probabilistic model;irregular computation;sparse matrix;cache performance |
277915 | Application and evaluation of large deviation techniques for traffic engineering in broadband networks. | Accurate yet simple methods for traffic engineering are important for efficient dimensioning of broadband networks. The goal of this paper is to apply and evaluate large deviation techniques for traffic engineering. In particular, we employ the recently developed theory of effective bandwidths, where the effective band... | Introduction
The rapid progress and successful penetration of broadband
communications in recent years has led to important new
problems in traffic modeling and engineering. Among oth-
ers, call admission control and network dimensioning for
cases of guaranteed QoS (which is one of the most important
features supported... | broadband networks;large deviations;effective bandwidths;traffic engineering;ATM |
277973 | Fast Multigrid Solution of the Advection Problem with Closed Characteristics. | The numerical solution of the advection-diffusion problem in the inviscid limit with closed characteristics is studied as a prelude to an efficient high Reynolds-number flow solver. It is demonstrated by a heuristic analysis and numerical calculations that using upstream discretization with downstream relaxation orderi... | Introduction
Efficient multigrid algorithms for the numerical solution of partial differential
problems normally require good ellipticity measures on all scales of
the problem, which implies that nonsmooth solution components can be re-solved
by local processing [2]. But problems with small ellipticity measures
are mar... | recirculating flow;upstream discretization;advection-diffusion;multigrid |
278097 | An Integral Invariance Principle for Differential Inclusions with Applications in Adaptive Control. | The Byrnes--Martin integral invariance principle for ordinary differential equations is extended to differential inclusions on {Bbb R}N. The extended result is applied in demonstrating the existence of adaptive stabilizers and servomechanisms for a variety of nonlinear system classes. | Introduction
. Suppose that -
semidynamical system on
R N with semiflow ' and so, for each x 0 2 R N , is the unique maximal
forwards-time solution of the initial-value problem -
In [2], Byrnes
Martin prove the following integral invariance principle: if '(\Delta; x 0 ) is bounded and
continuous function l : R N ! R+ :... | differential inclusions;universal servomechanisms;invariance principles;nonlinear systems;adaptive control |
278098 | Optimal Boundary Control of the Stokes Fluids with Point Velocity Observations. | This paper studies constrained linear-quadratic regulator (LQR) problems in distributed boundary control systems governed by the Stokes equation with point velocity observations. Although the objective function is not well defined, we are able to use hydrostatic potential theory and a variational inequality in a Banach... | Introduction
.
In this paper, we are concerned with the problems in boundary control of fluid
flows. We consider the following constrained optimal boundary control problems in
the systems governed by the Stokes equation with point velocity observations.
Let\Omega ae R 3 be a bounded domain with smooth boundary \Gamma, ... | hydrostatic potential;boundary integral equation;stokes fluid;singularity decomposition;distributed boundary control;point observation;LQR |
278124 | Lipschitzian Stability for State Constrained Nonlinear Optimal Control. | For a nonlinear optimal control problem with state constraints, we give conditions under which the optimal control depends Lipschitz continuously in the L2 norm on a parameter. These conditions involve smoothness of the problem data, uniform independence of active constraint gradients, and a coercivity condition for t... | Introduction
We consider the following optimal control problem involving a parameter:
minimize
subject to
where the state x(t) 2 R
dt x, the control u(t) 2 R m , the parameter p lies
in a metric space, the functions h
Throughout the paper, L ff (J denotes the usual Lebesgue space
of functions equipped with its standard... | optimal control;state constraints;lipschitzian stability;implicit function theorem |
278885 | Connectors for Mobile Programs. | AbstractSoftware Architecture has put forward the concept of connector to express complex relationships between system components, thus facilitating the separation of coordination from computation. This separation is especially important in mobile computing due to the dynamic nature of the interactions among participat... | Introduction
As the complexity of software systems grows, the role of Software Architecture is increasingly seen as the unifying
infrastructural concept/model on which to analyse and validate the overall system structure in various phases of the
software life cycle. In consequence, the study of Software Architecture ha... | transient interactions;connectors;UNITY;software architecture |
278970 | A Framework-Based Approach to the Development of Network-Aware Applications. | AbstractModern networks provide a QoS (quality of service) model to go beyond best-effort services, but current QoS models are oriented towards low-level network parameters (e.g., bandwidth, latency, jitter). Application developers, on the other hand, are interested in quality models that are meaningful to the end-user... | INTRODUCTION
applications use networks to provide access to remote
services and resources. However, in today's net-
works, users experience large variations in performance; e.g.,
bandwidth or latency may change by several orders of magnitude
during a session.
Such dramatic changes are observed in mobile environments
(w... | frameworks;software construction;network-aware computing;adaptive applications |
279011 | Unsupervised Segmentation of Markov Random Field Modeled Textured Images Using Selectionist Relaxation. | AbstractAmong the existing texture segmentation methods, those relying on Markov random fields have retained substantial interest and have proved to be very efficient in supervised mode. The use of Markov random fields in unsupervised mode is, however, hampered by the parameter estimation problem. The recent solutions ... | INTRODUCTION
Textured image segmentation consists in partitioning an image into regions that are
homogeneous with regards to some texture measure. Texture description is an important
issue with respect to this task. Existing texture segmentation methods are
commonly classified according to the texture description they ... | genetic algorithms;unsupervised texture segmentation;selectionist relaxation;partition function approximation;markov/gibbs random fields |
279017 | A Hierarchical Latent Variable Model for Data Visualization. | AbstractVisualization has proven to be a powerful and widely-applicable tool for the analysis and interpretation of multivariate data. Most visualization algorithms aim to find a projection from the data space down to a two-dimensional visualization space. However, for complex data sets living in a high-dimensional spa... | Introduction
Many algorithms for data visualization have been proposed by both the neural computing
and statistics communities, most of which are based on a projection of the data onto a two-dimensional
visualization space. While such algorithms can usefully display the structure
of simple data sets, they often prove i... | maximum likelihood;latent variables;principal component analysis;factor analysis;statistics;density estimation;hierarchical mixture model;EM algorithm;data visualization;clustering |
279092 | Interpolating Arithmetic Read-Once Formulas in Parallel. | A formula is read-once if each variable appears in it at most once. An arithmetic formula is one in which the operations are addition, subtraction, multiplication, and division (and constants are allowed). We present a randomized (Las Vegas) parallel algorithm for the exact interpolation of arithmetic read-once formula... | Introduction
The problem of interpolating a formula (from some class C) is the problem of exactly
identifying the formula from queries to the assignment (membership) oracle.
The interpolation algorithm queries the oracle with an assignment a and the oracle
returns the value of the function at a.
There are a number of c... | read-once formula;learning theory;parallel algorithm |
279128 | Localizing a Robot with Minimum Travel. | We consider the problem of localizing a robot in a known environment modeled by a simple polygon P. We assume that the robot has a map of P but is placed at an unknown location inside P. From its initial location, the robot sees a set of points called the visibility polygon V of its location. In general, sensing at a... | Introduction
Numerous tasks for a mobile robot require it to have a map of its environment and knowledge of
where it is located in the map. Determining the position of the robot in the environment is known
as the robot localization problem. To date, mobile robot research that supposes the use of a map
generally assumes... | navigation;optimization;localization;visibility;positioning;NP-hard;competitive strategy;robot;sensing |
279140 | A Controlled Experiment to Assess the Benefits of Procedure Argument Type Checking. | Type checking is considered an important mechanism for detecting programming errors, especially interface errors. This report describes an experiment to assess the defect-detection capabilities of static, intermodule type checking. The experiment uses ANSI C and Kernighan&Ritchie (K&R) C. The relevant difference is tha... | Introduction
The notion of data type is an important concept in
programming languages. A data type is an interpretation
applied to a datum, which otherwise would just
be a sequence of bits. The early FORTRAN compilers
already used type information to generate efficient
code for expressions. For instance, the code produ... | controlled experiment;defects;productivity;quality;type checking |
279143 | Optimal Elections in Faulty Loop Networks and Applications. | AbstractLoop networks (or Hamiltonian circulant graphs) are a popular class of fault-tolerant network topologies which include rings and complete graphs. For this class, the fundamental problem of Leader Election has been extensively studied, assuming either a fault-free system or an upper-bound on the number of link f... | Introduction
1.1 Loop Networks
A common technique to improve reliability of ring networks is to introduce link redun-
dancy; that is, to have each node connected to two or more additional nodes in the
network. With alternate paths between nodes, the network can sustain several nodes and
links failures. Several ring net... | fault tolerance;loop networks;interconnection networks;leader election;sense of direction;distributed algorithms |
279154 | Logic Testing of Bridging Faults in CMOS Integrated Circuits. | AbstractWe describe a system for simulating and generating accurate tests for bridging faults in CMOS ICs. After introducing the Primitive Bridge Function, a characteristic function describing the behavior of a bridging fault, we present the Test Guarantee Theorem, which allows for accurate test generation for feedback... | Introduction
In the search for increased quality of integrated circuits, manufacturers must ensure that shipped
parts are actually good. To do this, manufacturers must test for the defects that are likely to occur.
Shen, Maly, and Ferguson have performed defect simulation experiments showing that the majority
of spot d... | realistic faults;test pattern generation;fault simulation;fault models;bridging faults |
279239 | An Unbiased Detector of Curvilinear Structures. | AbstractThe extraction of curvilinear structures is an important low-level operation in computer vision that has many applications. Most existing operators use a simple model for the line that is to be extracted, i.e., they do not take into account the surroundings of a line. This leads to the undesired consequence tha... | Introduction
Extracting curvilinear structures, often simply called lines, in digital images is an important low-level
operation in computer vision that has many applications. In photogrammetric and remote
sensing tasks it can be used to extract linear features, including roads, railroads, or rivers, from
satellite or ... | lines;medical images;contour linking;feature extraction;aerial images;low-level processing;scale-space;curvilinear structures |
279243 | A Generic Grouping Algorithm and Its Quantitative Analysis. | AbstractThis paper presents a generic method for perceptual grouping quality. The grouping method is fairly general: It may be used the grouping of various types of data features, and to incorporate different grouping cues operating over feature sets of different sizes. The proposed method is divided into two parts: co... | Introduction
This work proposes a generic algorithm for perceptual grouping. The paper presents the new
approach, and focuses on analyzing the relation between the information available to the
grouping process and the corresponding grouping quality. The proposed generic algorithm
may serve to generate domain specific g... | maximum likelihood;generic grouping algorithm;perceptual grouping;grouping analysis;performance prediction;Wald's SPRT;graph clustering |
279249 | Decomposition of Arbitrarily Shaped Binary Morphological Structuring Elements Using Genetic Algorithms. | AbstractA number of different algorithms have been described in the literature for the decomposition of both convex binary morphological structuring elements and a specific subset of nonconvex ones. Nevertheless, up to now no deterministic solutions have been found to the problem of decomposing arbitrarily shaped struc... | INTRODUCTION
MATHEMATICAL morphology [1], [2], [3] concerns the study of shape
using the tools of set theory. Mathematical morphology has been
extensively used in low-level image processing and analysis appli-
cations, since it allows to filter and/or enhance only some characteristics
of objects, depending on their mor... | genetic algorithms;arbitrarily shaped structuring element decomposition;mathematical morphology |
279272 | A Volumetric/Iconic Frequency Domain Representation for Objects With Application for Pose Invariant Face Recognition. | AbstractA novel method for representing 3D objects that unifies viewer and model centered object representations is presented. A unified 3D frequency-domain representation (called Volumetric Frequency RepresentationVFR) encapsulates both the spatial structure of the object and a continuum of its views in the same data ... | Introduction
A major problem in 3-D object recognition is the method of representation, which actually
determines to a large extent, the recognition methodology and approach. The large variety
of representation methods presented in the literature do not provide a direct link between the
3-D object representation and it... | Volumetric frequency representation VFR;pose invariant face recognition;object representation;4D Fourier space;face pose estimation;projection-slice theorem |
279531 | An Efficient Solution to the Cache Thrashing Problem Caused by True Data Sharing. | AbstractWhen parallel programs are executed on multiprocessors with private caches, a set of data may be repeatedly used and modified by different threads. Such data sharing can often result in cache thrashing, which degrades memory performance. This paper presents and evaluates a loop restructuring method to reduce or... | Introduction
Parallel processing systems with memory hierarchies have become quite common today. Commonly,
most multiprocessor systems have a local cache in each processor to bridge the speed gap between the
processor and the main memory. Some systems use multi-level caches [5, 14]. Very often, a copy-back
snoopy cache... | multiprocessors;parallelizing compilers;parallel threads;loop transformations;cache thrashing;true data sharing |
279583 | Modulo Scheduling with Reduced Register Pressure. | AbstractSoftware pipelining is a scheduling technique that is used by some product compilers in order to expose more instruction level parallelism out of innermost loops. Modulo scheduling refers to a class of algorithms for software pipelining. Most previous research on modulo scheduling has focused on reducing the nu... | Introduction
Increasing the instruction level parallelism is an observed trend in the design of current
microprocessors. This requires a combined effort from the hardware and software in order
to be effective. Since most of the execution time of common programs is spent in loops,
many efforts to improve performance hav... | software pipelining;register allocation;register spilling;loop scheduling;instruction scheduling |
279588 | Algorithms for Variable Length Subnet Address Assignment. | AbstractIn a computer network that consists of M subnetworks, the L-bit address of a machine consists of two parts: A prefix si that contains the address of the subnetwork to which the machine belongs, and a suffix (of length L$-$ |si|) containing the address of that particular machine within its subnetwork. In fixed-l... | Introduction
This introduction discusses the connection between computer networking and the abstract problems
for which algorithms are subsequently given. It also introduces some terminology.
In a computer network that consists of M subnetworks, the L-bit address of a machine consists
of two parts: A prefix that contai... | prefix codes;addressing;algorithms;computer networks |
279589 | Analysis of Cache-Related Preemption Delay in Fixed-Priority Preemptive Scheduling. | AbstractWe propose a technique for analyzing cache-related preemption delays of tasks that cause unpredictable variation in task execution time in the context of fixed-priority preemptive scheduling. The proposed technique consists of two steps. The first step performs a per-task analysis to estimate cache-related pree... | INTRODUCTION
In real-time systems, tasks have timing constraints that must be satisfied for correct op-
eration. To guarantee such timing constraints, extensive studies have been performed on
schedulability analysis [1, 2, 3, 4, 5, 6]. They, in many cases, make a number of assumptions
to simplify the analysis. One such... | cache memory;fixed-priority scheduling;preemption;schedulability analysis;real-time system |
279654 | Checkpointing Distributed Shared Memory. | Distributed shared memory (DSM) is a very promising programming model for exploiting the parallelism of distributed memory systems, because it provides a higher level of abstraction than simple message passing. Although the nodes of standard distributed systems exhibit high crash rates only very few DSM environments ha... | INTRODUCTION
Distributed Shared Memory (DSM) systems provide the shared memory programming
model on top of distributed memory systems (i.e. distributed memory multiprocessors or
networks of workstations). DSM is appealing because it combines the performance and
scalability of distributed memory systems with the ease of... | portability;fault-tolerance;checkpointing;distributed shared memory |
280273 | Using permutations in regenerative simulations to reduce variance. | We propose a new estimator for a large class of performance measures obtained from a regenerative simulation of a system having two distinct sequences of regeneration times. To construct our new estimator, we first generate a sample path of a fixed number of cycles based on one sequence of regeneration times, divide t... | INTRODUCTION
The regenerative method is a simulation-output-analysis technique for estimating
certain performance measures of regenerative stochastic systems; see [Crane and
Iglehart 1975]. The basis of the approach is to divide the sample path into i.i.d.
segments (cycles), where the endpoints of the segments are dete... | variance reduction;permutations;efficiency improvement;regenerative simulation |
280293 | Intelligent Adaptive Information Agents. | Adaptation in open, multi-agent information gathering systems is important for several reasons. These reasons include the inability to accurately predict future problem-solving workloads, future changes in existing information requests, future failures and additions of agents and data supply resources, and other future... | Introduction
Adaptation is behavior of an agent in response to unexpected
(i.e., low probability) events or dynamic environments. Examples
of unexpected events include the unscheduled failure
of an agent, an agent's computational platform, or underlying
information sources. Examples of dynamic environments include
the ... | intelligent agents;Distributed AI;agent architectures;Multi-Agent Systems;information gathering |
280345 | 3-D Scene Data Recovery Using Omnidirectional Multibaseline Stereo. | A traditional approach to extracting geometric information from a large scene is to compute multiple 3-D depth maps from stereo pairs or direct range finders, and then to merge the 3-D data. However, the resulting merged depth maps may be subject to merging errors if the relative poses between depth maps are not known ... | Introduction
A traditional approach to extracting geometric information from a large scene is to compute multiple
(possibly numerous) 3-D depth maps from stereo pairs, and then to merge the 3-D data [Ferrie
and Levine, 1987; Higuchi et al., 1993; Parvin and Medioni, 1992; Shum et al., 1994]. This is not
only computatio... | 3-D median filtering;omnidirectional stereo;panoramic structure from motion;scene modeling;8-point algorithm;multibaseline stereo |
281209 | Multiple Experiment Environments for Testing. | Concurrent simulation (CS) has been used successfully as a replacement for serial simulation. Based on storing differences from experiments, CS saves storage, speeds up simulation time and allows excellent internal observation of events. In this paper, we introduce Multiple Domain Concurrent Simulation (MDCS) which lik... | Introduction
Concurrent Simulation(CS)[1, 2] has been proven
to be powerful and efficient for simulating single
stuck-at faults but inadequate for exhaustive applications
like Multiple Stuck-at Fault (MSAF)
simulations. It was developed as a speedup mechanism
over serial simulation, thus experiments are
independent and... | scenario;interactive experimentation;concurrent fault simulation;multiple stuck-at |
282692 | Gossiping on Meshes and Tori. | AbstractAlgorithms for performing gossiping on one- and higher-dimensional meshes are presented. As a routing model, the practically important wormhole routing is assumed. We especially focus on the trade-off between the start-up time and the transmission time. For one-dimensional arrays and rings, we give a novel lowe... | Introduction
Meshes and Tori. One of the most thoroughly investigated interconnection schemes for parallel
computers is the n\Thetan mesh, in which n 2 processing units (PUs) are connected by a two-dimensional grid of
communication links. A torus is a mesh with wrap-around connections. Their immediate generalizations
a... | wormhole routing;mesh networks;torus networks;gossip;global communication |
282725 | An Efficient Algorithm for Row Minima Computations on Basic Reconfigurable Meshes. | AbstractA matrix A of size mn containing items from a totally ordered universe is termed monotone if, for every i, j, 1 i < jm, the minimum value in row j lies below or to the right of the minimum in row i. Monotone matrices, and variations thereof, are known to have many important applications. In particular, the prob... | Introduction
Recently, in an attempt to reduce its large computational diameter, the mesh-connected architecture
has been enhanced with various broadcasting capabilities. Some of these involve endowing the
mesh with static buses, that is buses whose configuration is fixed and cannot change; more recently,
researches ha... | basic reconfigurable meshes;monotone matrices;cellular system design;row minima;search problems;facility location problems;VLSI design;reconfigurable meshes;totally monotone matrices |
282729 | Designing Masking Fault-Tolerance via Nonmasking Fault-Tolerance. | AbstractMasking fault-tolerance guarantees that programs continually satisfy their specification in the presence of faults. By way of contrast, nonmasking fault-tolerance does not guarantee as merely guarantees that when faults stop occurring, program executions converge to states from where programs continually (re)sa... | Introduction
In this paper, we present a new method for the design of "masking" fault-tolerant systems [1-4].
We focus our attention on masking fault-tolerance because it is often a desirable -if not an ideal-
property for system design: masking the effects of faults ensures that a system always satisfies its
problem s... | masking and nonmasking fault-tolerance;correctors;stepwise design formal methods;distributed systems;component based design;detectors |
284742 | Local Convergence of the Symmetric Rank-One Iteration. | We consider conditions under which the SR1 iteration is locally convergent. We apply the result to a pointwise structured SR1 method that has been used in optimal control. | Introduction
. The symmetric rank-one (SR1) update [1] is a quasi-Newton
method that preserves symmetry of an approximate Hessian (optimization problems)
or Jacobian (nonlinear equations). The analysis in this paper is from the nonlinear
equations point of view. Our purpose is to prove a local convergence result using
... | optimal control;SR1 update;pointwise quasi-Newton method |
284954 | Approximation Algorithms for the Feedback Vertex Set Problem with Applications to Constraint Satisfaction and Bayesian Inference. | A feedback vertex set of an undirected graph is a subset of vertices that intersects with the vertex set of each cycle in the graph. Given an undirected graph G with n vertices and weights on its vertices, polynomial-time algorithms are provided for approximating the problem of finding a feedback vertex set of G with s... | Introduction
E) be an undirected graph and let be a weight function on
the vertices of G. A cycle in G is a path whose two terminal vertices coincide. A feedback
vertex set of G is a subset of vertices F ' V (G) such that each cycle in G passes through
at least one vertex in F . In other words, a feedback vertex set F ... | bayesian networks;combinatorial optimization;approximation algorithms;constraint satisfaction;vertex feedback set |
284962 | Surface Approximation and Geometric Partitions. | Motivated by applications in computer graphics, visualization, and scientific computation, we study the computational complexity of the following problem: given a set S of n points sampled from a bivariate function f(x,y) and an input parameter $\eps > 0$, compute a piecewise-linear function $\Sigma(x,y)$ of minimum co... | Introduction
In scientific computation, visualization, and computer graphics, the modeling and construction
of surfaces is an important area. A small sample of some recent papers [2, 3, 5, 7, 10,
13, 20, 21] on this topic gives an indication of the scope and importance of this problem.
The first author has been support... | simplification;visualization;approximation algorithms;levels of detail;dynamic programming;machine learning;terrains |
284973 | Computational Complexity and Knowledge Complexity. | We study the computational complexity of languages which have interactive proofs of logarithmic knowledge complexity. We show that all such languages can be recognized in ${\cal BPP}^{\cal NP}$. Prior to this work, for languages with greater-than-zero knowledge complexity only trivial computational complexity bounds ... | Introduction
The notion of knowledge-complexity was introduced in the seminal paper of Goldwasser
Micali and Rackoff [GMR-85, GMR-89]. Knowledge-complexity (KC) is intended to measure
the computational advantage gained by interaction. Satisfactory formulations of knowledge-
complexity, for the case that it is not zero,... | knowledge complexity;interactive proofs;randomness;cryptography;complexity classes;zero knowledge |
284976 | Guaranteeing Fair Service to Persistent Dependent Tasks. | We introduce a new scheduling problem that is motivated by applications in the area of access and flow control in high-speed and wireless networks. An instance of the problem consists of a set of persistent tasks that have to be scheduled repeatedly. Each task has a demand to be scheduled "as often as possible." There ... | Introduction
In this paper we consider a new form of a scheduling
problem which is characterized by two features:
Persistence of the tasks: A task does not simply go
away once it is scheduled. Instead, each task must
be scheduled innitely many times. The goal is to
schedule every task as frequently as possible.
Depende... | dining philosophers problem;fairness;interval graphs;scheduling |
284994 | An Algorithm for Finding the Largest Approximately Common Substructures of Two Trees. | AbstractOrdered, labeled trees are trees in which each node has a label and the left-to-right order of its children (if it has any) is fixed. Such trees have many applications in vision, pattern recognition, molecular biology and natural language processing. We consider a substructure of an ordered labeled tree T to be... | Introduction
Ordered, labeled trees are trees in which each node has a label and the left-to-right order of its children (if
it has any) is fixed. 1 Such trees have many applications in vision, pattern recognition, molecular biology
and natural language processing, including the representation of images [12], patterns ... | trees;pattern recognition;dynamic programming;pattern matching;computational biology |
285006 | On the Power of Finite Automata with both Nondeterministic and Probabilistic States. | We study finite automata with both nondeterministic and random states (npfa's). We restrict our attention to those npfa's that accept their languages with a small probability of error and run in polynomial expected time. Equivalently, we study Arthur--Merlin games where Arthur is limited to polynomial time and consta... | Introduction
The classical subset construction of Rabin and Scott [25] shows that finite state automata with
just nondeterministic states (nfa's) accept exactly the regular languages. Results of Rabin
[24], Dwork and Stockmeyer [7] and Kaneps and Freivalds [17] show that the same is true of
probabilistic finite state a... | nondeterministic probabilistic finite automata;interactive proof systems;matrix tiling;hankel matrices;arthur-merlin games |
285057 | Formal verification of complex coherence protocols using symbolic state models. | Directory-based coherence protocols in shared-memory multiprocessors are so complex that verification techniques based on automated procedures are required to establish their correctness. State enumeration approaches are well-suited to the verification of cache protocols but they face the problem of state space explosi... | Introduction
Caching data close to the processor dynamically is an important technique for reducing
the latency of memory accesses in a shared-memory multiprocessor system. Because multiple
copies of the same memory block may exist, a cache coherence protocol often maintains coherence
among all data copies [29]. In lar... | state enumeration methods;formal methods;cache coherence protocols;shared-memory multiprocessors;state abstraction |
285060 | Property testing and its connection to learning and approximation. | In this paper, we consider the question of determining whether a function f has property P or is &egr;-far from any function with property P. A property testing algorithm is given a sample of the value of f on instances drawn according to some distribution. In some cases, it is also allowed to query f on instances of i... | Introduction
We are interested in the following general question of Property
Let P be a fixed property of functions, and f
be an unknown function. Our goal is to determine (possibly
if f has property P or if it is far from any
function which has property P, where distance between functions
is measured with respect to s... | approximation algorithms;computational learning theory;graph algorithms |
285064 | A Theory for Total Exchange in Multidimensional Interconnection Networks. | AbstractTotal exchange (or multiscattering) is one of the important collective communication problems in multiprocessor interconnection networks. It involves the dissemination of distinct messages from every node to every other node. We present a novel theory for solving the problem in any multidimensional (cartesian p... | Introduction
Multidimensional (or cartesian product) networks have prevailed the interconnection network design
for distributed memory multiprocessors both in theory and in practice. Commercial machines
like the Ncube, the Cray T3D, the Intel iPSC, Delta and Paragon, have a node interconnection
structure based on multi... | total exchange;collective communications;interconnection networks;packet-switched networks;multidimensional networks |
285099 | Capabilities-Based Query Rewriting in Mediator Systems. | Users today are struggling to integrate a broad range of information sources providing different levels of query capabilities. Currently, data sources with different and limited capabilities are accessed either by writing rich functional wrappers for the more primitive sources, or by dealing with all sources at a lowes... | Introduction
Organizations today must integrate multiple heterogeneous
information sources, many of which are
not conventional SQL database management systems.
Examples of such information sources include bibliographic
databases, object repositories, chemical structure
databases, WAIS servers, etc. Some of these system... | query containment;heterogeneous sources;query rewriting;cost optimization;mediator systems |
285120 | A Parallel Algorithm to Reconstruct Bounding Surfaces in 3D Images. | The growing size of 3D digital images causes sequential algorithms to be less and less usable on whole images and a parallelization of these algorithm is often required. We have developed an algorithm named Sewing Faces which synthesizes both geometrical and topological information on bounding surface of 6-connected3D ... | Introduction
Over the past decade, 3D digitalization techniques such as the Magnetic Resonance Imaging
have been extensively developed. They have opened new research topics in 3D digital image
processing and are of primary importance in many application domains such as medical imaging.
The classical notions of 2D image... | computer graphics;parallel applications;3D digital images;coars and fine-grain parallelization;bounding surfaces reconstruction |
285191 | Linearly Derived Steiner Triple Systems. | We attach a graph to every Steiner triple system. The chromatic number of this graph is related to the possibility of extending the triple system to a quadruple system. For example, the triple systems with chromatic number one are precisely the classical systems of points and lines of a projective geometry over the two... | Introduction
In November of 1852 Steiner [32] posed an infinite series of questions concerning
what are now known as Steiner triple systems. The second of these
questions asked whether or not it was always possible, given a Steiner triple
system on n points, to introduce n(n 4-subsets of the underlying
set of the given... | graphs;chromatic number;derived triple systems;steiner triple systems |
285263 | Achieving bounded fairness for multicast and TCP traffic in the Internet. | There is an urgent need for effective multicast congestion control algorithms which enable reasonably fair share of network resources between multicast and unicast TCP traffic under the current Internet infrastructure. In this paper, we propose a quantitative definition of a type of bounded fairness between multicast a... | Introduction
Given the ubiquitous presence of TCP traffic in the Internet,
one of the major barriers for the wide-range deployment
of reliable multicast is the lack of an effective congestion
control mechanism which enables multicast traffic to share
network resources reasonably fairly with TCP. Because it is
crucial f... | internet;phase effect;RED and drop-tail gateways;flow and congestion control;multicast |
286191 | Efficient Distributed Detection of Conjunctions of Local Predicates. | AbstractGlobal predicate detection is a fundamental problem in distributed systems and finds applications in many domains such as testing and debugging distributed programs. This paper presents an efficient distributed algorithm to detect conjunctive form global predicates in distributed systems. The algorithm detects ... | Introduction
Development of distributed applications requires the ability to analyze their behavior
at run time whether to debug or control the execution. In particular, it is sometimes
essential to know if a property is satisfied (or not) by a distributed computation.
Properties of the computation, which specify desir... | on-the-fly global predicate detection;distributed systems |
286949 | Safe metaclass programming. | In a system where classes are treated as first class objects, classes are defined as instances of other classes called metaclasses. An important benefit of using metaclasses is the ability to assign properties to classes (e.g. being abstract, being final, tracing particular messages, supporting multiple inheritance), i... | Introduction
It has been shown that programming with metaclasses is of great benefit [KAJ
interesting use of metaclasses is the assignment of specific properties to classes. For example, a class can
be abstract, have a unique instance, trace messages received by its instances, define pre-post conditions on
its methods,... | compatibility;class property propagation;metaclasses;class specific properties |
286966 | Visualizing dynamic software system information through high-level models. | Dynamic information collected as a software system executes can help software engineers perform some tasks on a system more effectively. To interpret the sizable amount of data generated from a system's execution, engineers require tool support. We have developed an off-line, flexible approach for visualizing the opera... | INTRODUCTION
Effective performance of many software engineering tasks requires
knowledge of how the system works. Gaining the desired
knowledge by studying or statically analyzing the source
code can be difficult. Static analysis, for instance, can help
a software engineer determine if two classes can interact, but
it ... | software visualization;performance;software structure;program comprehension;execution trace;programming environments |
286977 | Multiple dispatch as dispatch on Tuples. | Many popular object-oriented programming languages, such as C++, Smalltalk-80, Java, and Eiffel, do not support multiple dispatch. Yet without multiple dispatch, programmers find it difficult to express binary methods and design patterns such as the "visitor" pattern. We describe a new, simple, and orthogonal way to ad... | INTRODUCTION
Single dispatch, as found in C++ [Stroustrup 97], Java
[Arnold & Gosling 98, Gosling et al. 96], Smalltalk-80
[Goldberg & Robson 83], and Eiffel [Meyer 92, Meyer 97],
selects a method using the dynamic class of one object, the
message's receiver. Multiple dispatch, as found in CLOS
[Chapter 28, Steele 90] ... | semantics;tuple;multimethods;generic functions;typing;binary methods;single dispatch;multiple dispatch;language design |
287011 | Similarity and Symmetry Measures for Convex Shapes Using Minkowski Addition. | AbstractThis paper is devoted to similarity and symmetry measures for convex shapes whose definition is based on Minkowski addition and the Brunn-Minkowski inequality. This means, in particular, that these measures are region-based, in contrast to most of the literature, where one considers contour-based measures. All ... | Introduction
The problem of shape similarity has been extensively investigated in both machine vision
and biological vision. Although for human perception, different features such as shape,
color, reflectance, functional information play an important role while comparing objects,
in machine vision usually only geometri... | symmetry measure;minkowski addition;convex set;similarity measure;brunn-minkowski inequality |
287016 | Location- and Density-Based Hierarchical Clustering Using Similarity Analysis. | AbstractThis paper presents a new approach to hierarchical clustering of point patterns. Two algorithms for hierarchical location- and density-based clustering are developed. Each method groups points such that maximum intracluster similarity and intercluster dissimilarity are achieved for point locations or point sepa... | Introduction
Clustering explores the inherent tendency of a point pattern to form sets of points
(clusters) in multidimensional space. Most of the previous clustering methods assume
tacitly that points having similar locations or constant density create a single cluster
(location- or density-based clustering). Two idea... | point patterns;density-based clustering;location-based clustering;hierarchy of clusters;spatially interleaved clusters;clustering |
287330 | Scalable S-To-P Broadcasting on Message-Passing MPPs. | AbstractIn s-to-p broadcasting, s processors in a p-processor machine contain a message to be broadcast to all the processors, 1 sp. We present a number of different broadcasting algorithms that handle all ranges of s. We show how the performance of each algorithm is influenced by the distribution of the s source proce... | Introduction
The broadcasting of messages is a basic communication
operation on coarse-grained, message passing
massively parallel processors (MPPs). In the
standard broadcast operation, one processor broadcasts
a message to every other processor. Various
implementations of this operation for architectures
with differe... | scalability;message-passing MPPs;broadcasting;communication operations |
287341 | Deterministic Voting in Distributed Systems Using Error-Correcting Codes. | AbstractDistributed voting is an important problem in reliable computing. In an N Modular Redundant (NMR) system, the N computational modules execute identical tasks and they need to periodically vote on their current states. In this paper, we propose a deterministic majority voting algorithm for NMR systems. Our votin... | Introduction
Distributed voting is an important problem in the creation of fault-tolerant computing systems,
e.g., it can be used to keep distributed data consistent, to provide mutual exclusion in distributed
systems. In an N Modular Redundant (NMR) system, when the N computational modules
execute identical tasks, the... | MDS code;error-correcting codes;NMR system;majority voting;communication complexity |
287352 | A comparison of reliable multicast protocols. | We analyze the maximum throughput that known classes of reliable multicast transport protocols can attain. A new taxonomy of reliable multicast transport protocols is introduced based on the premise that the mechanisms used to release data at the source after correct delivery should be decoupled from the mechanisms use... | Introduction
The increasing popularity of real-time applications supporting
either group collaboration or the reliable dissemination
of multimedia information over the Internet is making the
provision of reliable and unreliable end-to-end multicast services
an integral part of its architecture. Minimally, an end-
to-en... | ACK implosion;multicast transport protocols;reliable multicast;tree-based protocols |
287532 | Using the Matrix Sign Function to Compute Invariant Subspaces. | The matrix sign function has several applications in system theory and matrix computations. However, the numerical behavior of the matrix sign function, and its associated divide-and-conquer algorithm for computing invariant subspaces, are still not completely understood. In this paper, we present a new perturbation th... | Introduction
. Since the matrix sign function was introduced in early 1970s,
it has been the subject of numerous studies and used in many applications. For
example, see [30, 31, 11, 26, 23] and references therein. Our main interest here is
to use the matrix sign function to build parallel algorithms for computing invar... | newton's method;matrix sign function;eigenvalue problem;deflating subspaces;invariant subspace |
287537 | Parameter Estimation in the Presence of Bounded Data Uncertainties. | We formulate and solve a new parameter estimation problem in the presence of data uncertainties. The new method is suitable when a priori bounds on the uncertain data are available, and its solution leads to more meaningful results, especially when compared with other methods such as total least-squares and robust esti... | Introduction
. The central problem in estimation is to recover, to good ac-
curacy, a set of unobservable parameters from corrupted data. Several optimization
criteria have been used for estimation purposes over the years, but the most im-
portant, at least in the sense of having had the most applications, are criteria... | least-squares estimation;total least-squares;regularized least-squares;ridge regression;secular equation;modeling errors;robust estimation |
287637 | Computing rank-revealing QR factorizations of dense matrices. | We develop algorithms and implementations for computing rank-revealing QR (RRQR) factorizations of dense matrices. First, we develop an efficient block algorithm for approximating an RRQR factorization, employing a windowed version of the commonly used Golub pivoting strategy, aided by incremental condition estimation.... | INTRODUCTION
We briefly summarize the properties of a rank-revealing QR factorization (RRQR
factorization). Let A be an m \Theta n matrix (w.l.o.g. m - n) with singular values
and define the numerical rank r of A with respect to a threshold - as follows:
oe r
oe r+1
Also, let A have a QR factorization of the form
R 11 ... | rank-revealing orthogonal factorization;block algorithm;QR factorization;least-squares systems;numerical rank |
287639 | An object-oriented framework for block preconditioning. | General software for preconditioning the iterative solution of linear systems is greatly lagging behind the literature. This is partly because specific problems and specific matrix and preconditioner data structures in order to be solved efficiently, i.e., multiple implementations of a preconditioner with specialized d... | INTRODUCTION
In the iterative solution of the linear system
a preconditioner M is often used to transform the system into one which has better
convergence properties, for example, in the left-preconditioned case,
M \Gamma1 is referred to as the preconditioning operator for the matrix A and, in general,
is a sequence of... | preconditioners;block matrices |
287640 | A combined unifrontal/multifrontal method for unsymmetric sparse matrices. | We discuss the organization of frontal matrices in multifrontal methods for the solution of large sparse sets of unsymmetric linear equations. In the multifrontal method, work on a frontal matrix can be suspended, the frontal matrix can be stored for later reuse, and a new frontal matrix can be generated. There are thu... | Introduction
. We consider the direct solution of sets of linear equations
the coefficient matrix A is sparse, unsymmetric, and has a general
nonzero pattern. In a direct approach, a permutation of the matrix A is factorized
into its LU factors, are permutation matrices chosen
to preserve sparsity and maintain numerica... | frontal methods;sparse unsymmetric matrices;linear equations;multifrontal methods |
287731 | On Two Interior-Point Mappings for Nonlinear Semidefinite Complementarity Problems. | Extending our previous work ( Monteiro and Pang 1996), this paper studies properties of two fundamental mappings associated with the family of interior-point methods for solving monotone nonlinear complementarity problems over the cone of symmetric positive semidefinite matrices. The first of these maps lead to a famil... | Introduction
In a series of recent papers (see Kojima, Shida and Shindoh 1995a, Kojima, Shida and Shindoh
1995b, Kojima, Shida and Shindoh 1996, Kojima, Shindoh and Hara 1997, Shida and Shindoh
1996, Shida, Shindoh and Kojima 1995, Shida, Shindoh and Kojima 1996), Hara, Kojima, Shida
and Shindoh have introduced the mon... | interior point methods;maximal monotonicity;problems;mixed nonlinear complementarity problems;generalized complementarity;nonlinear semidefinite programming;weighted central path;monotone mappings;continuous trajectories |
287884 | Engineering Software Design Processes to Guide Process Execution. | AbstracttUsing systematic development processes is an important characteristic of any mature engineering discipline. In current software practice, Software Design Methodologies (SDMs) are intended to be used to help design software more systematically. This paper shows, however, that one well-known example of such an S... | Introduction
If software engineering is to make solid progress
towards becoming a mature discipline, then it must
move in the direction of establishing standardized, disciplined
methods and processes that can be used systematically
by practitioners in carrying out their routine
software development tasks. We note that ... | software design process;design methodology;design methods |
288204 | Applications of non-Markovian stochastic Petri nets. | nets represent a powerful paradigm for modeling parallel and distributed systems. Parallelism and resource contention can easily be captured and time can be included for the analysis of system dynamic behavior. Most popular stochastic Petri nets assume that all firing times are exponentially distributed. This is found ... | Introduction
Over the past decade, stochastic and timed Petri
nets of several kinds have been proposed to overcome
limitations on the modeling capabilities of
Petri nets (PNs). Although very powerful in capturing
synchronization of events and contention for
R.M. Fricks is with the SIMEPAR Laboratory and
Ponticia Univer... | stochastic Petri nets;numerical analysis;markov regenerative processes;preemption policies |
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