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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288212 | Analysis of windowing mechanisms with infinite-state stochastic Petri nets. | In this paper we present a performance evaluation of windowing mechanisms in world-wide web applications. Previously, such mechanisms have been studied by means of measurements only, however, given suitable tool support, we show that such evaluations can also be performed conveniently using infinite-state stochastic Pe... | Introduction
W HEN modeling and evaluating the performance of
modern distributed systems, complex system behavior
(involving networks, switches, servers, flow control
mechanisms, etc.) as well as very complex workloads (often
a mix of batch data, interactive data and real-time data for
voice and video) need to be taken... | matrix-geometric methods;window flow control;congestion control;stochastic Petri nets |
288307 | Filter-based model checking of partial systems. | Recent years have seen dramatic growth in the application of model checking techniques to the validation and verification of correctness properties of hardware, and more recently software, systems. Most of this work has been aimed at reasoning about properties of complete systems. This paper describes an automatable ap... | INTRODUCTION
Modern software is, increasingly, built as a collection
of independently produced components which are assembled
to achieve a system's requirements. A typical
software system consists of instantiations of generic,
reusable components and components built specifically
This work was supported in part by NSF ... | filter-based analysis;assume-guarantee reasoning;software verification and validation;model checking |
288321 | Automated test data generation using an iterative relaxation method. | An important problem that arises in path oriented testing is the generation of test data that causes a program to follow a given path. In this paper, we present a novel program execution based approach using an iterative relaxation method to address the above problem. In this method, test data generation is initiated w... | Introduction
Software testing is an important stage of software develop-
ment. It provides a method to establish confidence in the
reliability of software. It is a time consuming process and
accounts for 50% of the cost of software development [10].
Given a program and a testing criteria, the generation of
test data th... | predicate sliccs;input dependency set;predicate residuals;relaxation methods;dynamic test data generation;path testing |
288811 | Learning to Recognize Volcanoes on Venus. | Dramatic improvements in sensor and image acquisition technology have created a demand for automated tools that can aid in the analysis of large image databases. We describe the development of JARtool, a trainable software system that learns to recognize volcanoes in a large data set of Venusian imagery. A machine lear... | Introduction
Detecting all occurrences of an object of interest in a set of images is a problem that
arises in many domains, including industrial product inspection, military surveil-
lance, medical diagnosis, astronomy, and planetary geology. Given the prevalence
of this problem and the fact that continued improvement... | automatic cataloging;data mining;detection of natural objects;principal components analysis;JARtool;volcanoes;trainable;learning from examples;pattern recognition;venus;machine learning;large image databases;Magellan SAR |
288858 | Interference-Minimizing Colorings of Regular Graphs. | Communications problems that involve frequency interference, such as the channel assignment problem in the design of cellular telephone networks, can be cast as graph coloring problems in which the frequencies (colors) assigned to an edge's vertices interfere if they are too similar. The paper considers situations mode... | Introduction
This paper is motivated by telecommunication problems such as the design of planar regions
for cellular telephone networks and the assignment of allowable frequencies to the regions. In
our graph abstraction, vertices are regions, edges are pairs of contiguous regions, and colors
correspond to frequencies.... | graph coloring;interference threshold;regular graph |
288859 | Combinatorial Properties and Constructions of Traceability Schemes and Frameproof Codes. | In this paper, we investigate combinatorial properties and constructions of two recent topics of cryptographic interest, namely frameproof codes for digital fingerprinting and traceability schemes for broadcast encryption. We first give combinatorial descriptions of these two objects in terms of set systems and also di... | Introduction
Traceability schemes for broadcast encryption were defined by Chor, Fiat and Naor [8], and
frameproof codes for digital fingerprinting were proposed by Boneh and Shaw [4]. Although
these two objects were designed for different purposes, they have some similar aspects. One
of the purposes of this paper is t... | traceability scheme;hash family;frameproof code;t-design |
288861 | A Randomness-Rounds Tradeoff in Private Computation. | We study the role of randomness in multiparty private computations. In particular, we give several results that prove the existence of a randomness-rounds tradeoff in multiparty private computation of $\fxor$. We show that with a single random bit, $\Theta(n)$ rounds are necessary and sufficient to privately compute $\... | Introduction
A 1-private (or simply, private) protocol A for computing a function f is a protocol that allows
possessing an individual secret input, x i , to compute the value
of f(~x) in a way that no single player learns more about the initial inputs of other players
than what is revealed by the value of f(~x) and it... | lower bounds;randomness;private distributed computations;sensitivity |
288866 | The Number of Intersection Points Made by the Diagonals of a Regular Polygon. | We give a formula for the number of interior intersection points made by the diagonals of a regular n-gon. The answer is a polynomial on each residue class modulo 2520. We also compute the number of regions formed by the diagonals, by using Euler's formula 2. | Introduction
We will find a formula for the number I(n) of intersection points formed inside
a regular n-gon by its diagonals. The case depicted in Figure 1. For a
generic convex n-gon, the answer would be
, because every four vertices would
be the endpoints of a unique pair of intersecting diagonals. But I(n) can be l... | intersection points;diagonals;adventitious quadrangles;regular polygons;roots of unity |
288868 | Rankings of Graphs. | A vertex (edge) coloring $\phi:V\rightarrow \{1,2,\ldots ,t\}$ ($\phi':E\rightarrow \{1,2,\ldots,$ $t\}$) of a graph G=(V,E) is a vertex (edge) t-ranking if, for any two vertices (edges) of the same color, every path between them contains a vertex (edge) of larger color. The {\em vertex ranking number} $\chi_{r}(G)$ ({... | Introduction
In this paper we consider vertex rankings and edge rankings of graphs. The vertex
ranking problem, also called the ordered coloring problem [15], has received
much attention lately because of the growing number of applications. There
are applications in scheduling problems of assembly steps in manufacturin... | edge ranking;treewidth;vertex ranking;graph algorithms;ranking of graphs;graph coloring |
288976 | Directions of Motion Fields are Hardly Ever Ambiguous. | If instead of the full motion field, we consider only the direction of the motion field due to a rigid motion, what can we say about the three-dimensional motion information contained in it? This paper provides a geometric analysis of this question based solely on the constraint that the depth of the surfaces in view i... | addition, in order to give practical significance to these uniqueness results for the case of
a limited field of view, we also characterize the locations on the image where the motion
vectors due to the different motions must have different directions.
additional constraints are met, then the two rigid
motions could pr... | motion field;egomotion;qualitative vision;optic flow |
289045 | A Nested FGMRES Method for Parallel Calculation of Nuclear Reactor Transients. | A semi-iterative method based on a nested application of Flexible Generalized Minimum Residual)FGMRES) was developed to solve the linear systems resulting from the application of the discretized two-phase hydrodynamics equations to nuclear reactor transient problems. The complex three-dimensional reactor problem is dec... | Introduction
. The analysis of nuclear reactor transient behavior has always
been one of the most difficult computational problems in nuclear engineering. Because
the computational load to calculate detailed three-dimensional solutions of the field
equations is prohibitive, variations of the power, flow, and temperatur... | fluid dynamics;Preconditioned GMRES;parallel computing;nuclear reactor simulation |
289829 | Stochastic Integration Rules for Infinite Regions. | Stochastic integration rules are derived for infinite integration intervals, generalizing rules developed by Siegel and O'Brien [ SIAM J. Sci. Statist. Comput., 6 (1985), pp. 169--181] for finite intervals. Then random orthogonal transformations of rules for integrals over the surface of the unit m-sphere are used to p... | Introduction
A common problem in applied science and statistics is to numerically compute integrals in the form
with . For statistics applications the function p(') may be an unnormalized unimodal
posterior density function and g(') is some function for which an approximate expected value is needed.
We are interested i... | multiple integrals;numerical integration;monte carlo;statistical computation |
289834 | Multigrid Method for Ill-Conditioned Symmetric Toeplitz Systems. | In this paper, we consider solutions of Toeplitz systems where the Toeplitz matrices An are generated by nonnegative functions with zeros. Since the matrices An are ill conditioned, the convergence factor of classical iterative methods, such as the damped Jacobi method, will approach one as the size n of the matrices b... | Introduction
In this paper we discuss the solutions of ill-conditioned symmetric Toeplitz systems A n by the
multigrid method. The n-by-n matrices A n are Toeplitz matrices with generating functions f that
are nonnegative even functions. More precisely, the matrices A n are constant along their diagonals
with their dia... | toeplitz matrices;multigrid method |
289843 | Accelerated Inexact Newton Schemes for Large Systems of Nonlinear Equations. | Classical iteration methods for linear systems, such as Jacobi iteration, can be accelerated considerably by Krylov subspace methods like GMRES @. In this paper, we describe how inexact Newton methods for nonlinear problems can be accelerated in a similar way and how this leads to a general framework that includes many... | Introduction
. Our goal in this paper is twofold. A number of iterative solvers
for linear systems of equations, such as FOM [23], GMRES [26], GCR [31], Flexible
GMRES [25], GMRESR [29] and GCRO [7], are in structure very similar to iterative
methods for linear eigenproblems, like shift and invert Arnoldi [1, 24], Davi... | nonlinear problems;iterative methods;newton's method;inexact Newton |
289882 | Quantitative Evaluation of Register Pressure on Software Pipelined Loops. | Software Pipelining is a loop scheduling technique that extracts loop parallelism by overlapping the execution of several consecutive iterations. One of the drawbacks of software pipelining is its high register requirements, which increase with the number of functional units and their degree of pipelining. This paper a... | Introduction
Current high-performance floating-point microprocessors try to maximize the exploitable
parallelism by: heavily pipelining functional units (1;2) , making aggressive
use of parallelism (3;4) , or a combination of both (5) which is the trend in current
and future high-performance microprocessors. To exploit... | SOFTWARE PIPELINING;REGISTER REQUIREMENTS;SPILL CODE;LOOP TRANSFORMATIONS;PERFORMANCE EVALUATION |
290063 | A Feasibility Decision Algorithm for Rate Monotonic and Deadline Monotonic Scheduling. | Rate monotonic and deadline monotonic scheduling are commonly used for periodic real-time task systems. This paper discusses a feasibility decision for a given real-time task system when the system is scheduled by rate monotonic and deadline monotonic scheduling. The time complexity of existing feasibility decision alg... | INTRODUCTION
Hard real-time systems have been defined as those containing processes that have
deadlines that cannot be missed [Bur89a]. Such deadlines have been termed hard: they
must be met under all circumstances otherwise catastrophic system failure may result
To meet hard deadlines implies constraints upon the way ... | deadline monotonic scheduling;priority inheritance protocol;rate monotonic scheduling;feasibility decision algorithm;periodic task |
290070 | The Synchronous Approach to Designing Reactive Systems. | Synchronous programming is available through several formally defined languages having very different characteristics: Esterel is imperative, while Lustre and Signal are declarative in style; Statecharts and Argos are graphical languages that allow one to program by constructing hierarchical automata. Our motivation fo... | Introduction
Reactive computer systems continuously respond to external stimuli generated by their en-
vironments. They are critical components of our technology dominated lives, be they in
control systems such as ABS for cars, fly-by-wire in aircraft, railway signalling, power gen-
eration, shopfloor automation, or in... | embedded software;synchronous automata;reactive systems;synchronous programming |
290092 | Filters, Random Fields and Maximum Entropy (FRAME). | This article presents a statistical theory for texture modeling. This theory combines filtering theory and Markov random field modeling through the maximum entropy principle, and interprets and clarifies many previous concepts and methods for texture analysis and synthesis from a unified point of view. Our theory chara... | Introduction
Texture is an important characteristic of the appearance of objects in natural scenes,
and is a powerful cue in visual perception. It plays an important role in computer vision,
graphics, and image encoding. Understanding texture is an essential part of understanding
human vision.
Texture analysis and synt... | texture analysis and synthesis;minimax entropy;texture modeling;markov random field;feature pursuit;visual learning;maximum entropy |
290114 | A Router Architecture for Real-Time Communication in Multicomputer Networks. | AbstractParallel machines have the potential to satisfy the large computational demands of real-time applications. These applications require a predictable communication network, where time-constrained traffic requires bounds on throughput and latency, while good average performance suffices for best-effort packets. Th... | Introduction
Real-time applications, such as avionics, industrial process
control, and automated manufacturing, impose strict
timing requirements on the underlying computing system.
As these applications grow in size and complexity, parallel
processing plays an important role in satisfying the
large computational deman... | link scheduling;packet switching;multicomputer router;wormhole switching;real-time communication |
290115 | Minimum Achievable Utilization for Fault-Tolerant Processing of Periodic Tasks. | AbstractThe Rate Monotonic Scheduling (RMS) policy is a widely accepted scheduling strategy for real-time systems due to strong theoretical foundations and features attractive to practical uses. For a periodic task set of n tasks with deadlines at the end of task periods, it guarantees a feasible schedule on a single p... | Introduction
In the realm of real-time computation, we frequently encounter systems where the tasks are required
to execute periodically. Applications where this requirement is common are often found in, for
example, process control, space applications, avionics and others. Even when the external events
that trigger ta... | minimum achievable utilization;real-time systems;rate monotonic scheduling;periodic tasks;fault tolerance |
290123 | Efficient Region Tracking With Parametric Models of Geometry and Illumination. | AbstractAs an object moves through the field of view of a camera, the images of the object may change dramatically. This is not simply due to the translation of the object across the image plane. Rather, complications arise due to the fact that the object undergoes changes in pose relative to the viewing camera, change... | Introduction
Visual tracking has emerged as an important component of systems in several application
areas including vision-based control [1, 32, 38, 15], human-computer interfaces [10, 14, 20],
surveillance [30, 29, 19], agricultural automation [27, 41], medical imaging [12, 4, 45] and
visual reconstruction [11, 42, 4... | motion estimation;real-time vision;visual tracking;illumination;robust statistics |
290124 | Scale-Space Derived From B-Splines. | AbstractIt is well-known that the linear scale-space theory in computer vision is mainly based on the Gaussian kernel. The purpose of the paper is to propose a scale-space theory based on B-spline kernels. Our aim is twofold. On one hand, we present a general framework and show how B-splines provide a flexible tool to ... | Introduction
Scale is a fundamental aspect of early image representation. Koenderink [1] emphasized that the
problem of scale must be faced in any imaging situation. A multiscale representation is of crucial
importance if one aims at describing the structure of the world. Both the psychophysical and
physiological exper... | b-spline;image modeling;scaling theorem;wavelet;scale-space;fingerprint theorem |
290131 | Efficient Error-Correcting Viterbi Parsing. | AbstractThe problem of Error-Correcting Parsing (ECP) using an insertion-deletion-substitution error model and a Finite State Machine is examined. The Viterbi algorithm can be straightforwardly extended to perform ECP, though the resulting computational complexity can become prohibitive for many applications. We propos... | Introduction
The problem of Error-Correcting Parsing (ECP) is fundamental in Syntactic Pattern
Recognition (SPR) [11, 13], where data is generally distorted or noisy. It also arises
in many other areas such as Language Modeling [23, 6], Speech Processing [7, 22],
OCR [18], Grammatical Inference [20], Coding Theory [8, ... | depth-first topological sort;shape recognition;viterbi algorithm;priority queues;error-correcting parsing;beam search;sequence alignment;language processing;bucketsort |
290216 | Simple Fast Parallel Hashing by Oblivious Execution. | A hash table is a representation of a set in a linear size data structure that supports constant-time membership queries. We show how to construct a hash table for any given set of n keys in O(lg lg n) parallel time with high probability, using n processors on a weak version of a concurrent-read concurrent-write paral... | Introduction
Let S be a set of n keys drawn from a finite universe U . The hashing problem is to construct a
with the following attributes:
Injectiveness: no two keys in S are mapped by H to the same value,
Space efficiency: both m and the space required to represent H are O(n), and
Time efficiency: for every x 2 U , H... | data structures;randomization;parallel computation;hashing |
290221 | Downward Separation Fails Catastrophically for Limited Nondeterminism Classes. | The $\beta$ hierarchy consists of classes $\beta_k={\rm NP}[logkn]\subseteq {\rm NP}$. Unlike collapses in the polynomial hierarchy and the Boolean hierarchy, collapses in the $\beta$ hierarchy do not seem to translate up, nor does closure under complement seem to cause the hierarchy to collapse. For any consistent s... | Introduction
. Although standard nondeterministic algorithms solve many
NP-complete problems with O(n) nondeterministic moves, there are other problems
that seem to require very different amounts of nondeterminism. For instance, clique
can be solved with only O(
n) nondeterministic moves, and Pratt's algorithm [16]
sol... | oracles;structural complexity theory;hierarchies;limited nondeterminism |
290287 | A rejection technique for sampling from log-concave multivariate distributions. | Different universal methods (also called automatic or black-box methods) have been suggested for sampling form univariate log-concave distributions. The descriptioon of a suitable universal generator for multivariate distributions in arbitrary dimensions has not been published up to now. The new algorithm is based on t... | Introduction
For the univariate case there is a large literature on generation methods for
standard distributions (see e.g. [Dev86] and [Dag88]) and in the last years some
papers appeared on universal (or black-box) methods (see [Dev86, chapter VII],
[GW92], [Ahr95], [H-or95a], [HD94] and [ES97]); these are algorithms ... | rejection method;multivariate log-concave distributions |
290382 | Mixed-Mode BIST Using Embedded Processors. | In complex systems, embedded processors may be used to run software routines for test pattern generation and response evaluation. For system components which are not completely random pattern testable, the test programs have to generate deterministic patterns after random testing. Usually the random test part of the pr... | Introduction
Integrating complex systems into single chips or implementing
them as multi-chip modules (MCMs) has become
a widespread approach. A variety of embedded processors
and other embedded coreware can be found on the
market, which allows to appropriately split the system
functionality into both hardware and soft... | embedded systems;deterministic BIST;BIST;random pattern testing |
290837 | Code generation for fixed-point DSPs. | This paper examines the problem of code-generation for Digital Signal Processors (DSPs). We make two major contributions. First, for an important class of DSP architectures, we propose an optimal O(n) algorithm for the tasks of register allocation and instruction scheduling for expression trees. Optimality is guarantee... | INTRODUCTION
Digital Signal Processors (DSPs) are receiving increased attention recently due to
their role in the design of modern embedded systems like video cards, cellular telephones
and other multimedia and communication devices. DSPs are largely used
in systems where general-purpose architectures are not capable o... | register allocation;scheduling;code generation |
290839 | Estimation of lower bounds in scheduling algorithms for high-level synthesis. | To produce efficient design, a high-level synthesis system should be able to analyze a variety of cost-performance tradeoffs. The system can use lower-bound performance estimated methods to identify and puune inferior designs without producint complete designs. We present a lower-bound performance estimate method that ... | Introduction
High-level synthesis takes an abstract behavioral specification of a digital system and finds a
register-transfer level structure that realizes the given behavior. Usually, there are many different
structures that can be used to realize a given behavior. One of the main goals of a synthesis
system is to fi... | high-level synthesis;lower-bound estimated;dynamic programming;scheduling |
291058 | Value speculation scheduling for high performance processors. | Recent research in value prediction shows a surprising amount of predictability for the values produced by register-writing instructions. Several hardware based value predictor designs have been proposed to exploit this predictability by eliminating flow dependencies for highly predictable values. This paper proposed a... | INTRODUCTION
Modern microprocessors extract instruction level
parallelism (ILP) by using branch prediction to break
control dependencies and by using dynamic memory
disambiguation to resolve memory dependencies [1].
However, current techniques for extracting ILP are still
insufficient. Recent research has focused on va... | value speculation;instruction level parallelism;VLIW instruction schedulings;value prediction |
291061 | An empirical study of decentralized ILP execution models. | Recent fascination for dynamic scheduling as a means for exploiting instruction-level parallelism has introduced significant interest in the scalability aspects of dynamic scheduling hardware. In order to overcome the scalability problems of centralized hardware schedulers, many decentralized execution models are being... | Introduction
To extract significant amounts of parallelism from sequential
programs, instruction-level parallel (ILP) processors often
perform dynamic scheduling. The hardware typically
collects decoded instructions in an instruction window, and
executes instructions as and when their source operands become
available. ... | speculative execution;instruction-level parallelism;hardware window;control dependence;dynamic scheduling;decentralization;execution unit dependence;data dependence |
291129 | Metric details for natural-language spatial relations. | Spatial relations often are desired answers that a geographic information system (GIS) should generate in response to a user's query. Current GIS's provide only rudimentary support for processing and interpreting natural-language-like spatial relations, because their models and representations are primarily quantitati... | Figure
1: Geometric interpretations of the 19 line-region relations that can be realized from the
9-intersection (Egenhofer and Herring 1991).
The only other topological invariant used here is the concept of the number of component. A
component is a separation of any of the nine intersections (Egenhofer and Franzosa 1... | geographic information systems;topological relations;spatial relations;metric refinements;GIS |
291275 | Performance Analysis of Stochastic Timed Petri Nets Using Linear Programming Approach. | AbstractStochastic timed Petri nets are a useful tool in performance analysis of concurrent systems such as parallel computers, communication networks, and flexible manufacturing systems. In general, performance measures of stochastic timed Petri nets are difficult to obtain for practical problems due to their sizes. I... | Introduction
Stochastic Timed Petri Nets (STPN) are Petri nets where transitions have -ring delays.
Since the last decade, they have been receiving increasing interest in the modeling and
performance analysis of discrete event systems. Such a tool is particularly useful for modeling
systems which exhibit concurrent, as... | mean token number;linear programming;throughput;stochastic timed petri net;uniformization;performance bound |
291356 | On Generalized Hamming Weights for Galois Ring Linear Codes. | The definition of generalized Hamming weights (GHW) for linear codes over Galois rings is discussed. The properties of GHW for Galois ring linear codes are stated. Upper and existence bounds for GHW of ZF_4 linear codes and a lower bound for GHW of the Kerdock code over Z_4 are derived. GHW of some ZF_4 linear codes ar... | Introduction
For any code D, -(D), the support of D, is the set of positions where not all the
codewords of D are zero, and w s (D), the support weight of D, is the weight of
-(D). For an [n; k] code C and any r, where 1 - r - k, the r-th Hamming weight
is defined [7],[14] by
d r is an [n; r] subcode of Cg:
In [1],[4],... | generalized Hamming weights;galois ring linear codes |
291364 | Time- and VLSI-Optimal Sorting on Enhanced Meshes. | AbstractSorting is a fundamental problem with applications in all areas of computer science and engineering. In this work, we address the problem of sorting on mesh connected computers enhanced by endowing each row and each column with its own dedicated high-speed bus. This architecture, commonly referred to as a mesh ... | Introduction
With the tremendous advances in VLSI, it is technologically feasible and economically viable
to build parallel machines featuring tens of thousands of processors [4, 22, 39, 40, 42, 47].
However, practice indicates that this increase in raw computational power does not always
translate into performance inc... | parallel algorithms;VLSI-optimality;lower bounds;sorting;meshes with multiple broadcasting;time-optimality |
291368 | Theoretical Analysis for Communication-Induced Checkpointing Protocols with Rollback-Dependency Trackability. | AbstractRollback-Dependency Trackability (RDT) is a property that states that all rollback dependencies between local checkpoints are on-line trackable by using a transitive dependency vector. In this paper, we address three fundamental issues in the design of communication-induced checkpointing protocols that ensure R... | Introduction
A distributed computation consists of a finite set of processes connected by a communication
network, that communicate and synchronize by exchanging messages through the network.
A local checkpoint is a snapshot of the local state of a process, saved on nonvolatile storage
to survive process failures. It c... | communication-induced protocols;checkpointing;rollback recovery;rollback-dependency trackability;on-line algorithms |
291369 | Diskless Checkpointing. | AbstractDiskless Checkpointing is a technique for checkpointing the state of a long-running computation on a distributed system without relying on stable storage. As such, it eliminates the performance bottleneck of traditional checkpointing on distributed systems. In this paper, we motivate diskless checkpointing and ... | Introduction
Checkpointing is an important topic in fault-tolerant computing as the basis for rollback recovery. Suppose a
user is executing a long-running computation and for some reason (hardware or software), the machine running the
computation fails. In the absence of checkpointing, when the machine becomes functio... | memory redundancy;checkpointing;RAID systems;error-correcting codes;rollback recovery;copy-on-write;fault tolerance |
291520 | Computing the Local Consensus of Trees. | The inference of consensus from a set of evolutionary trees is a fundamental problem in a number of fields such as biology and historical linguistics, and many models for inferring this consensus have been proposed. In this paper we present a model for deriving what we call a local consensus tree T from a set of trees... | Introduction
An evolutionary tree (also called a phylogeny or phylogenetic tree) for a species set S is a rooted
tree with leaves labeled by distinct elements in S. Because evolutionary history is difficult
to determine (it is both computationally difficult as most optimization problems in this area are
NP-hard, and sc... | graphs;algorithms;evolutionary trees |
291523 | First-Order Queries on Finite Structures Over the Reals. | We investigate properties of finite relational structures over the reals expressed by first-order sentences whose predicates are the relations of the structure plus arbitrary polynomial inequalities, and whose quantifiers can range over the whole set of reals. In constraint programming terminology, this corresponds to... | Introduction
In this paper we are motivated by two fields of
computer science which heavily rely on logic: relational
databases and constraint programming.
We will look at the latter from the perspective of
the former.
In classical relational database theory [1], a database
is modeled as a relational structure. The
dom... | linear arithmetic;first-order logic;relational databases;constraint programming |
291534 | An Asymptotic-Induced Scheme for Nonstationary Transport Equations in the Diffusive Limit. | An asymptotic-induced scheme for nonstationary transport equations with the diffusion scaling is developed. The scheme works uniformly for all ranges of mean-free paths. It is based on the asymptotic analysis of the diffusion limit of the transport equation.A theoretical investigation of the behavior of the scheme in t... | Introduction
. Transport equations are used to describe many physical phe-
nomena. Some of the best known examples are neutron transport, radiative transfer
equations, semiconductors or gas kinetics. The situation for small mean free paths
is mathematically described by an asymptotic analysis. Depending on the transpor... | asymptotic analysis;diffusion limit;transport equations;numerical methods for stiff equations |
291683 | On Residue Symbols and the Mullineux Conjecture. | This paper is concerned with properties of the Mullineux map, which plays a rle in p-modular representation theory of symmetric groups. We introduce the residue symbol for a p-regular partitions, a variation of the Mullineux symbol, which makes the detection and removal of good nodes (as introduced by Kleshchev) in the... | Introduction
It is a well known fact that for a given prime p the p-modular irreducible
representations D - of the symmetric group S n of degree n are labelled in a
canonical way by the p-regular partitions - of n. When the modular irreducible
representation D - of S n is tensored by the sign representation we get a ne... | signature sequence;good nodes in residue diagram;modular representation;mullineux conjecture;symmetric group |
291689 | The Enumeration of Fully Commutative Elements of Coxeter Groups. | A Coxeter group element w is fully commutative if any reduced expression for w can be obtained from any other via the interchange of commuting generators. For example, in the symmetric group of degree n, the number of fully commutative elements is the nth Catalan number. The Coxeter groups with finitely many fully comm... | Introduction
A Coxeter group element w is said to be fully commutative if any reduced word for w
can be obtained from any other via the interchange of commuting generators. (More
explicit definitions will be given in Section 1 below.)
For example, in the symmetric group of degree n, the fully commutative elements are
t... | coxeter group;braid relation;reduced word |
292363 | An Iterative Perturbation Method for the Pressure Equation in the Simulation of Miscible Displacement in Porous Media. | The miscible displacement problem in porous media is modeled by a nonlinear coupled system of two partial differential equations: the pressure-velocity equation and the concentration equation. An iterative perturbation procedure is proposed and analyzed for the pressure-velocity equation, which is capable of producing ... | Introduction
Miscible displacement occurs, for example, in the tertiary oil-recovery process which can enhance
hydrocarbon recovery in the petroleum reservoir. This process involves the injection of a solvent
at injection wells with the intention of displacing resident oil to production wells. The resident
oil may have... | miscible displacement;iterative method;perturbation method;galerkin method;flow in porous media |
292374 | A Sparse Approximate Inverse Preconditioner for Nonsymmetric Linear Systems. | This paper is concerned with a new approach to preconditioning for large, sparse linear systems. A procedure for computing an incomplete factorization of the inverse of a nonsymmetric matrix is developed, and the resulting factorized sparse approximate inverse is used as an explicit preconditioner for conjugate gradien... | Introduction
. In this paper we consider the solution of nonsingular linear systems
of the form
(1)
where the coefficient matrix A 2 IR n\Thetan is large and sparse. In particular, we are concerned
with the development of preconditioners for conjugate gradient-type methods. It is well-known
that the rate of convergence... | approximate inverses;incomplete factorizations;sparse linear systems;conjugate gradient-type methods;sparse matrices;preconditioning |
292377 | Approximate Inverse Preconditioners via Sparse-Sparse Iterations. | The standard incomplete LU (ILU) preconditioners often fail for general sparse indefinite matrices because they give rise to "unstable" factors L and U. In such cases, it may be attractive to approximate the inverse of the matrix directly. This paper focuses on approximate inverse preconditioners based on minimizing ... | Introduction
. The incomplete LU factorization preconditioners were originally
developed for M-matrices that arise from the discretization of very simple partial
differential equations of elliptic type, usually in one variable. For the rather common
situation where the matrix A is indefinite, standard ILU factorization... | approximate inverse;threshold dropping strategies;preconditioning;krylov subspace methods |
292401 | Perturbation Analyses for the Cholesky Downdating Problem. | New perturbation analyses are presented for the block Cholesky downdating problem These show how changes in R and X alter the Cholesky factor U. There are two main cases for the perturbation matrix $\D R$ in R: (1) $\D R$ is a general matrix; (2)$\D R$ is an upper triangular matrix. For both cases, first-order perturba... | Introduction
. Let A 2 R n\Thetan be a symmetric positive definite matrix. Then
there exists a unique upper triangular matrix R 2 R n\Thetan with positive diagonal elements
such that A = R T R. This factorization is called the Cholesky factorization,
and R is called the Cholesky factor of A.
In this paper we give pertu... | asymptotic condition;downdating;cholesky factorization;perturbation analysis;sensitivity;condition |
292410 | Condition Numbers of Random Triangular Matrices. | Let Ln be a lower triangular matrix of dimension n each of whose nonzero entries is an independent N(0,1) variable, i.e., a random normal variable of mean 0 and variance 1. It is shown that kn, the 2-norm condition number of Ln, satisfies \begin{equation*} \sqrt[n]{\kn} \rightarrow 2 \:\:\: \text{\it almost surely} \en... | Introduction
Random dense matrices are well-conditioned. If each of the n 2 entries of a
matrix of dimension n is an independent N(0; 1) variable, Edelman has shown
This work was supported by NSF Grant DMS-9500975CS and DOE Grant DE-FG02-
y Department of Computer Science, Cornell University, Ithaca, NY 14853 (diva-
kar... | exponentially nonnormal matrices;matrix condition numbers;random triangular matrices;strong limit theorems |
292837 | Continuous Time Matching Constraints for Image Streams. | Corresponding image points of a rigid object in a discrete sequence of images fulfil the so-called multilinear constraint. In this paper the continuous time analogue of this constraint, for a continuous stream of images, is introduced and studied. The constraint links the Taylor series expansion of the motion of the im... | Introduction
A central problem in scene analysis is the analysis
of 3D-objects from a number of its 2D-images,
obtained by projections. In this paper, the case of
rigid point con-gurations with known correspondences
is treated. The objective is to calculate the
shape of the object using the shapes of the images
and to ... | multilinear constraint;calibrated camera;structure;motion;optical flow;uncalibrated |
292853 | The Hector Distributed Run-Time Environment. | AbstractHarnessing the computational capabilities of a network of workstations promises to off-load work from overloaded supercomputers onto largely idle resources overnight. Several capabilities are needed to do this, including support for an architecture-independent parallel programming environment, task migration, a... | INTRODUCTION
AND PREVIOUS WORK
A. Networks of Workstations
Networked workstations have been available for many years. Since a modern network of
workstations represents a total computational capability on the order of a supercomputer, there is
strong motivation to use a network of workstations (NOW) as a type of low-cos... | task migration;load balancing;fault tolerance;resource allocation;parallel computing |
292856 | A Fault-Tolerant Dynamic Scheduling Algorithm for Multiprocessor Real-Time Systems and Its Analysis. | AbstractMany time-critical applications require dynamic scheduling with predictable performance. Tasks corresponding to these applications have deadlines to be met despite the presence of faults. In this paper, we propose an algorithm to dynamically schedule arriving real-time tasks with resource and fault-tolerant req... | Introduction
Real-time systems are defined as those systems in which the correctness of the system depends not only
on the logical result of computation, but also on the time at which the results are produced [22]. Real-
This work was supported by the Indian National Science Academy, and the Department of Science and T... | run-time anomaly;dynamic scheduling;fault tolerance;safety critical application;resource reclaiming;real-time system |
293004 | New Perspectives in Turbulence. | Intermittency, a basic property of fully developed turbulent flow, decreases with growing viscosity; therefore classical relationships obtained in the limit of vanishing viscosity must be corrected when the Reynolds number is finite but large. These corrections are the main subject of the present paper. They lead to a ... | Introduction
In February 1996 I had the privilege of meeting Prof. G.I. Barenblatt, who had just
arrived in Berkeley. In our first extended conversation we discovered that we had been
working on similar problems with different but complementary tools, which, when wielded
in unison, led to unexpected results. We have be... | wall-bounded turbulence;local structure;intermittency;statistical theory;turbulence;scaling |
293148 | Boundary representation deformation in parametric solid modeling. | One of the major unsolved problems in parametric solid modeling is a robust update (regeneration) of the solid's boundary representation, given a specified change in the solid's parameter values. The fundamental difficulty lies in determining the mapping between boundary representations for solids in the same parametri... | consumer applications, probably has to do more with development and successful marketing of new parametric
("feature-based" and "constraint-based") user interfaces than with the mathematical soundness of solid
modeling systems. These parametric interfaces allow the user to define and modify solid models in terms of
hig... | parametric editing;boundary deformation;cell complex;algebraic topology;persistent naming;soild modeling;boundary representation |
293633 | The edge-based design rule model revisited. | A model for integrated circuit design rules based on rectangle edge constraints has been proposed by Jeppson, Christensson, and Hedenstierna. This model appears to be the most rigorous proposed to date for the description of such edge-based design rules. However, in certain rare circumstances their model is unable to e... | Introduction
The technology used to manufacture integrated circuits [8] imposes certain limits on the sizes and relative positioning
of features on the wafer. The resolution of optical lithography equipment, the amount of undercutting during a
wet-etch processing step, the control over lateral diffusion and junction de... | design rules;layout verification;design rule checking |
293906 | Discrete Lotsizing and Scheduling by Batch Sequencing. | The discrete lotsizing and scheduling problem for one machine with sequence-dependent setup times and setup costs is solved as a single machine scheduling problem, which we term the batch sequencing problem. The relationship between the lotsizing problem and the batch sequencing problem is analyzed. The batch sequencin... | Introduction
In certain manufacturing systems a significant amount of setup is required to change production from
one type of products to another, such as in the scheduling of production lines or in chemical engineering.
Productivity can then be increased by batching in order to avoid setups. However, demand for differ... | batch sequencing;Sequence-Dependent Setup Times and Setup Costs;Bounding/Dominance Rule;Discrete Lotsizing and Scheduling;Branch-and-Bound Algorithm |
293922 | Synthesis of Novel Views from a Single Face Image. | Images formed by a human face change with viewpoint. A new technique is described for synthesizing images of faces from new viewpoints, when only a single 2D image is available. A novel 2D image of a face can be computed without explicitly computing the 3D structure of the head. The technique draws on a single generic ... | Introduction
Given only a driver's license photograph of a
person's face, can one infer how the face might
look like from a different viewpoint? The three-dimensional
structure of an object determines how
the image of the object changes with a change in
viewpoint. With viewpoint changes, some previously
visible regions... | face recognition;flexible templates;image synthesis;rotation invariance |
293923 | Quasi-Invariant Parameterisations and Matching of Curves in Images. | In this paper, we investigate quasi-invariance on a smooth manifold, and show that there exist quasi-invariant parameterisations which are not exactly invariant but approximately invariant under group transformations and do not require high order derivatives. The affine quasi-invariant parameterisation is investigated ... | Introduction
The distortions of an image curve caused by the
relative motion between the observer and the
scene can be described by specific transformation
groups (Mundy and Zisserman, 1992). For exam-
ple, the corresponding pair of contour curves of
a surface of revolution projected on to an image
center can be descri... | bilateral symmetry;integral invariants;semi-local invariants;differential invariants;curve matching;quasi-invariant parameterisations |
293932 | Rational Filters for Passive Depth from Defocus. | A fundamental problem in depth from defocus is the measurement of relative defocus between images. The performance of previously proposed focus operators are inevitably sensitive to the frequency spectra of local scene textures. As a result, focus operators such as the Laplacian of Gaussian result in poor depth estimat... | Introduction
A pertinent problem in computational vision is the recovery of three-dimensional scene
structure from two-dimensional images. Of all problems studied in vision, the above
has, by far, attracted the most attention. This has resulted in a variety of sensors and
algorithms [Jarvis-1983, Besl-1988] that can be... | scene textures;texture invariance;depth estimation;blur function;depth confidence measure;normalized image ratio;real-time performance;passive depth from defocus;broadband rational operators |
294178 | The Efficient Computation of Sparse Jacobian Matrices Using Automatic Differentiation. | This paper is concerned with the efficient computation of sparse Jacobian matrices of nonlinear vector maps using automatic differentiation (AD). Specifically, we propose the use of a graph coloring technique, bicoloring, to exploit the sparsity of the Jacobian matrix J and thereby allow for the efficient determination... | Introduction
The efficient numerical solution of nonlinear systems of algebraic equations, F
usually requires the repeated calculation or estimation of the matrix of first derivatives, the Jacobian
In large-scale problems matrix J is often sparse and it is important to exploit
this fact in order to efficiently determin... | sparse finite differencing;NP-complete problems;ADOL-C;automatic differentiation;nonlinear systems of equations;bicoloring;computational differentiation;sparse Jacobian matrices;partition problem;nonlinear least squares;graph coloring |
294403 | Inertias of Block Band Matrix Completions. | This paper classifies the ranks and inertias of hermitian completion for the partially specified 3 x 3 block band hermitian matrix (also known as a "bordered matrix") P=\pmatrix{A&B&?\cr B^*&C&D\cr ?&D^*&E}. The full set of completion inertias is described in terms of seven linear inequalities involving inertias and ra... | Introduction
We address the following completion problem: given a partially specified hermitian matrix
characterize all the possible inertias In d) of the various hermitian completions H of
P: We call this set the "inertial set" or "inertial polygon" of P .
The issue of classifying positive definite and semidefinite co... | matrices;minimal rank;inertia;hermitian;completion |
295659 | Finitary fairness. | Fairness is a mathematical abstraction: in a multiprogramming environment, fairness abstracts the details of admissible (fair) schedulers; in a distributed environment, fairness abstracts the relative speeds of processors. We argue that the standard definition of fairness often is unnecessarily weak and can be replaced... | Introduction
Interleaving semantics provides an elegant and abstract way of modeling concurrent computation.
In this approach, a computation of a concurrent system is obtained by letting, at each step, one of
the enabled processes execute an atomic instruction. If all interleaving computations of a system
satisfy a pro... | distributed consensus;modeling of asynchronous systems;fairness;program verification |
295660 | Space/time-efficient scheduling and execution of parallel irregular computations. | In this article we investigate the trade-off between time and space efficiency in scheduling and executing parallel irregular computations on distributed-memory machines. We employ acyclic task dependence graphs to model irregular parallelism with mixed granularity, and we use direct remote memory access to support fas... | INTRODUCTION
Considerable effort in parallel system research has been spent on time-efficient par-
allelizations. This article investigates the trade-off between time and space efficiency
in executing irregular computations when memory capacity on each processor is
limited, since a time-efficient parallelization may le... | irregular parallelism;run-time support;DAG scheduling;direct remote memory access |
295662 | Equality-based flow analysis versus recursive types. | Equality-based control-flow analysis has been studied by Henglein, Bondorf and Jrgensen, DeFouw, Grove, and Chambers, and others. It is faster than the subset-based-0-CFA, but also more approximate. Heintze asserted in 1995 that a program can be safety checked with an equality-based control-flow analysis if and only if... | Introduction
Control-flow analysis is done to determine approximate sets of functions that may be called
from the call sites in a program. In this paper we address an instance of the question:
Question: How does flow analysis relate to type systems?
Our focus is on:
1. equality-based control-flow analysis which has bee... | flow analysis;type systems |
295663 | A new, simpler linear-time dominators algorithm. | We present a new linear-time algorithm to find the immediate dominators of all vertices in a flowgraph. Our algorithm is simpler than previous linear-time algorithms: rather than employ complicated data structures, we combine the use of microtrees and memoization with new observations on a restricted class of path comp... | INTRODUCTION
We consider the problem of nding the immediate dominators of vertices in a
graph. A
owgraph is a directed graph r) with a distinguished start
vertex , such that there is a path from r to each vertex in V . Vertex
w dominates vertex v if every path from r to v includes w; w is the immediate
dominator (idom)... | compilers;dominators;microtrees;path compression;flowgraphs |
295681 | Coordinating agent activities in knowledge discovery processes. | Knowledge discovery in databases (KDD) is an increasingly widespread activity. KDD processes may entail the use of a large number of data manipulation and analysis techniques, and new techniques are being developed on an ongoing basis. A challenge for the effective use of KDD is coordinating the use of these techniques... | INTRODUCTION
KDD-knowledge discovery in databases-has become a
widespread activity undertaken by an increasing number
and variety of industrial, governmental, and research
organizations. KDD is used to address diverse and often
unprecedented questions on issues ranging from marketing,
to fraud detection, to Web analysi... | knowledge discovery process;process programming;agent coordination;knowledge representation;agenda management |
295692 | The design of an interactive online help desk in the Alexandria Digital Library. | In large software systems such as digital libraries, electronic commerce applications, and customer support systems, the user interface and system are often complex and difficult to navigate. It is necessary to provide users with interactive online support to help users learn how to effectively use these applications. ... | INTRODUCTION
Online customer service systems such as "Call Centers" or
"Customer Care Centers" have been widely used, e.g., home-
banking, telephone registration, online shopping, airline ticket
booking, and digital libraries, etc. However, most of
Supported in part by NSF grants IRI-9411330 and IRI-9700370.
To appear ... | online support;digital library;user interface;online help desk;collaboration |
296252 | Time and Cost Trade-Offs in Gossiping. | Each of n processors has a value which should be transmitted to all other processors. This fundamental communication task is called gossiping. In a unit of time every processor can communicate with at most one other processor and during such a transmission each member of a communicating pair learns all values currently... | Introduction
Gossiping (also called all-to-all broadcasting) is one of the fundamental tasks in network
communication. Every node of a network (processor) has a piece of information (value)
which has to be transmitted to all other nodes, by exchanging messages along the links
of the network. Gossiping algorithms have b... | gossiping;lower bounds;algorithm |
296347 | High-level design verification of microprocessors via error modeling. | A design verification methodology for microprocessor hardware based on modeling design errors and generating simulation vectors for the modeled errors via physical fault testing techniques is presented. We have systematically collected design error data from a number of microprocessor design projects. The error data i... | INTRODUCTION
It is well known that about a third of the cost of developing a new microprocessor is devoted
to hardware debugging and testing [25]. The inadequacy of existing hardware verification
methods is graphically illustrated by the Pentium's FDIV error, which cost its manufacturer
an estimated $500 million. The d... | design errors;error modeling;design verification |
296377 | Extracting Hidden Context. | Concept drift due to hidden changes in context complicates learning in many domains including financial prediction, medical diagnosis, and communication network performance. Existing machine learning approaches to this problem use an incremental learning, on-line paradigm. Batch, off-line learners tend to be ineffectiv... | Introduction
In real world machine learning problems, there can be important properties of the
domain that are hidden from view. Furthermore, these hidden properties may
change over time. Machine learning tools applied to such domains must not only
be able to produce classifiers from the available data, but must be abl... | concept drift;hidden context;contextual clustering;batch learning;context-sensitive learning |
296379 | Tracking the Best Disjunction. | Littlestone developed a simple deterministic on-line learning algorithm for learning k-literal disjunctions. This algorithm (called {\sc Winnow}) keeps one weight for each of then variables and does multiplicative updates to its weights. We develop a randomized version of {\sc Winnow} and prove bounds for an adaptation... | Introduction
One of the most significant successes of the Computational Learning Theory community
has been Littlestone's formalization of an on-line model of learning and
the development of his algorithm Winnow for learning disjunctions (Littlestone,
1989, 1988). The key feature of Winnow is that when learning disjunct... | concept drift;prediction;computational learning theory;amortized analysis;on-line learning |
296382 | Tracking the Best Expert. | We generalize the recent relative loss bounds for on-line algorithms where the additional loss of the algorithm on the whole sequence of examples over the loss of the best expert is bounded. The generalization allows the sequence to be partitioned into segments, and the goal is to bound the additional loss of the algor... | Introduction
Consider the following on-line learning model. The learning occurs in a series of
trials labeled In each trial t the goal is to predict the outcome y t 2 [0; 1]
which is received at the end of the trial. At the beginning of trial t, the algorithm
receives an n-tuple x t . The element x t;i 2 [0; 1] of the ... | experts;multiplicative updates;shifting;amortized analysis;on-line learning |
296419 | On Asymptotics in Case of Linear Index-2 Differential-Algebraic Equations. | Asymptotic properties of solutions of general linear differential-algebraic equations (DAEs) and those of their numerical counterparts are discussed. New results on the asymptotic stability in the sense of Lyapunov as well as on contractive index-2 DAEs are given. The behavior of the backward differentiation formula (B... | Introduction
. The present paper is devoted to the study of asymptotic properties
of solutions of differential-algebraic equations (DAE's) on infinite intervals and
those of their numerical counterparts in integration methods. It is rather surprising
that, in spite of numerous papers on numerical integration, there are... | asymptotic properties;backward differentiation formulas;differential-algebraic equation;runge-kutta method;stability |
296420 | On Improving the Convergence of Radau IIA Methods Applied to Index 2 DAEs. | This paper presents a simple new technique to improve the order behavior of Runge--Kutta methods when applied to index 2 differential-algebraic equations. It is then shown how this can be incorporated into a more efficient version of the code {\sc radau5} developed by E. Hairer and G. Wanner. | Introduction
In recent years, differential algebraic equations (DAEs) have been studied by various authors (see
[HW91], [HLR89], [BCP91]), and their importance acknowledged by the development of specific solvers
such as DASSL from [Pet86] or RADAU5 from [HW91]. An especially important class of DAEs arising
in practice ... | rooted trees;runge-kutta methods;composition;differential-algebraic systems of index 2;Radau IIA methods;simplifying assumptions |
296955 | Rapid Concept Learning for Mobile Robots. | Concept learning in robotics is an extremely challenging problem: sensory data is often high-dimensional, and noisy due to specularities and other irregularities. In this paper, we investigate two general strategies to speed up learning, based on spatial decomposition of the sensory representation, and simultaneous lea... | Introduction
Programming mobile robots to successfully operate in unstructured environments,
including offices and homes, is tedious and difficult. Easing this programming burden
seems necessary to realize many of the possible applications of mobile robot
technology [7]. One promising avenue towards smarter and easier-... | robot learning;neural networks;concept learning |
297106 | Power balance and apportionment algorithms for the United States Congress. | We measure the performance, in the task of apportioning the Congress of the United States, of an algorithm combining a heuristic-driven (simulated annealing) search with an exact-computation dynamic programming evaluation of the apportionments visited in the search. We compare this with the actual algorithm currently u... | 1. MOTIVATION AND OVERVIEW
How should the seats in the House of Representatives of the United States be
allocated among the states? The Constitution stipulates only that "Representa-
tives shall be apportioned among the several states according to their respective
numbers, counting the whole numbers of persons in each ... | simulated annealing;power indices;apportionment algorithms |
297115 | Coordination of heterogeneous distributed cooperative constraint solving. | In this paper we argue for an alternative way of designing cooperative constraint solver systems using a control-oriented coordination language. The idea is to take advantage of the coordination features of MANIFOLD for improving the constraint solver collaboration language of BALI. We demonstrate the validity of our i... | INTRODUCTION
The need for constraint solver collaboration is widely rec-
ognized. The general approach consists of making several
solvers cooperate in order to process constraints that could
not be solved (at least not efficiently) by a single solver.
BALI [21, 23, 22] is a realization of such a system, in terms of
a l... | constraint solver cooperation;dynamic coordination;solver collaboration language;coordination model |
297118 | Coordinating autonomous entities with STL. | This paper describes ECM, a new coordination model and STL its corresponding language. STL's power and expressiveness are shown through a distributed implementation of a generic autonomy-based multi-agent system, which is applied to a collective robotics simulation, thus demonstrating the appropriateness of STL for dev... | Introduction
Coordination constitutes a major scientific domain
of Computer Science. Works coming within Coordination
encompass conceptual and methodological issues
as well as implementations in order to efficiently
help expressing and implementing distributed appli-
cations. Autonomous Agents, a discipline of Artifici... | autonomous agents;distributed systems;coordination;collective robotics |
297577 | Supporting Scenario-Based Requirements Engineering. | AbstractScenarios have been advocated as a means of improving requirements engineering yet few methods or tools exist to support scenario-based RE. The paper reports a method and software assistant tool for scenario-based RE that integrates with use case approaches to object-oriented development. The method and operati... | Introduction
Several interpretations of scenarios have been proposed ranging from examples of
behaviour drawn from use cases [29], descriptions of system usage to help understand
socio-technical systems [30], and experience based narratives for requirements elicitation
and validation [39], [50]. Scenarios have been adv... | scenarios;use cases;reuse;requirements engineering;scenario generation;exception types;patterns |
297588 | The Use of Cooperation Scenarios in the Design and Evaluation of a CSCW System. | AbstractDesign and evaluation of groupware systems raise questions which do not have to be addressed in the context of single user systems. The designer has to take into account not only the interaction of a single user with the computer, but also the computer-supported interaction of several users with each other. In ... | Introduction
COMPUTER SUPPORTED COOPERATIVE WORK (CSCW) is an interdisciplinary field of research, dealing with
cooperative work supported by computer systems (for an overview see e.g. [6]). Computer science naturally is a
major contributor. However, psychology, sociology, and other disciplines are involved, as well. T... | access control;evaluation;design methodology;groupware;CSCW;cooperation scenarios;scenario-based design |
297636 | Convergence to Second Order Stationary Points in Inequality Constrained Optimization. | We propose a new algorithm for the nonlinear inequality constrained minimization problem, and prove that it generates a sequence converging to points satisfying the KKT second order necessary conditions for optimality. The algorithm is a line search algorithm using directions of negative curvature and it can be viewed ... | Introduction
We are concerned with the inequality constrained minimization problem (P)
min f(x)
are three times continuously differentiable.
Our aim is to develope an algorithm that generates sequences converging to points
x satisfying, together with a suitable multiplier - 2 IR m , both the KKT first order
necessary o... | inequality constrained optimization;penalty function;KKT second order necessary conditions;LC 1 function;negative curvature direction |
297706 | A Trace Cache Microarchitecture and Evaluation. | AbstractAs the instruction issue width of superscalar processors increases, instruction fetch bandwidth requirements will also increase. It will eventually become necessary to fetch multiple basic blocks per clock cycle. Conventional instruction caches hinder this effort because long instruction sequences are not alway... | Introduction
High performance superscalar processor organizations
divide naturally into an instruction fetch mechanism and an
instruction execution mechanism. These two mechanisms
are separated by instruction issue buffers, for example, issue
queues or reservation stations. Conceptually, the instruction
fetch mechanism... | multiple branch prediction;instruction fetching;trace cache;instruction cache;superscalar processors |
297709 | Automatic Compiler-Inserted Prefetching for Pointer-Based Applications. | AbstractAs the disparity between processor and memory speeds continues to grow, memory latency is becoming an increasingly important performance bottleneck. While software-controlled prefetching is an attractive technique for tolerating this latency, its success has been limited thus far to array-based numeric codes. I... | Introduction
OFTWARE -controlled data prefetching [1], [2] offers
the potential for bridging the ever-increasing speed
gap between the memory subsystem and today's high-performance
processors. In recognition of this potential,
a number of recent processors have added support for
prefetch instructions [3], [4], [5]. Whi... | compiler optimization;prefetching;performance evaluation;caches;shared-memory multiprocessors;recursive data structures;pointer-based applications |
297713 | Analysis of Temporal-Based Program Behavior for Improved Instruction Cache Performance. | AbstractIn this paper, we examine temporal-based program interaction in order to improve layout by reducing the probability that program units will conflict in an instruction cache. In that context, we present two profile-guided procedure reordering algorithms. Both techniques use cache line coloring to arrive at a fin... | Introduction
C ACHE memories are found on most microprocessors
designed today. Caching the instruction stream can
be very beneficial since instruction references exhibit a high
degree of spatial and temporal locality. Still, cache misses
will occur for one of three reasons [1]:
1. first time reference,
2. finite cache ... | temporal locality;instruction caches;conflict misses;program reordering;graph pruning;graph coloring |
297715 | Randomized Cache Placement for Eliminating Conflicts. | AbstractApplications with regular patterns of memory access can experience high levels of cache conflict misses. In shared-memory multiprocessors conflict misses can be increased significantly by the data transpositions required for parallelization. Techniques such as blocking which are introduced within a single threa... | Introduction
If the upward trend in processor clock frequencies during
the last ten years is extrapolated over the next ten years,
we will see clock frequencies increase by a factor of twenty
during that period [1]. However, based on the current 7%
per annum reduction in DRAM access times [2], memory
latency can be exp... | cache architectures;performance evaluation;conflict avoidance |
297718 | The Impact of Exploiting Instruction-Level Parallelism on Shared-Memory Multiprocessors. | AbstractCurrent microprocessors incorporate techniques to aggressively exploit instruction-level parallelism (ILP). This paper evaluates the impact of such processors on the performance of shared-memory multiprocessors, both without and with the latency-hiding optimization of software prefetching. Our results show that... | Introduction
Shared-memory multiprocessors built from commodity
microprocessors are being increasingly used to provide high
performance for a variety of scientific and commercial ap-
plications. Current commodity microprocessors improve
performance by using aggressive techniques to exploit high
levels of instruction-le... | instruction-level parallelism;performance evaluation;shared-memory multiprocessors;software prefetching |
297811 | Bayesian Function Learning Using MCMC Methods. | AbstractThe paper deals with the problem of reconstructing a continuous one-dimensional function from discrete noisy samples. The measurements may also be indirect in the sense that the samples may be the output of a linear operator applied to the function (linear inverse problem, deconvolution). In some cases, the lin... | Introduction
The problem of reconstructing (learning) an unknown function from a set of experimental
data plays a fundamental role in engineering and science. In the present paper,
the attention is restricted to scalar functions of a scalar variable
the main ideas may apply to more general maps as well. In the most fav... | system identification;inverse problems;Markov chain Monte Carlo methods;dynamic systems;smoothing;bayesian estimation |
297817 | Bayesian Classification With Gaussian Processes. | AbstractWe consider the problem of assigning an input vector to one of m classes by predicting P(c|${\schmi x}$) for m. For a two-class problem, the probability of class one given ${\schmi x}$ is estimated by (y(${\schmi x}$)), where Gaussian process prior is placed on y(${\schmi x}$), and is combined with the training... | Introduction
We consider the problem of assigning an input vector x to one out of m classes by predicting P (cjx) for
classic example of this method is logistic regression. For a two-class problem, the probability
of class 1 given x is estimated by oe(w T x+ b), where \Gammay ). However, this method is not at all
"flex... | gaussian processes;Markov chain Monte Carlo;classification problems;hybrid Monte Carlo;bayesian classification;parameter uncertainty |
297877 | A Positive Acknowledgment Protocol for Causal Broadcasting. | AbstractCausal broadcasting has been introduced to reduce the asynchrony of communication channels inside groups of processes. It states that if two broadcast messages are causally related by the happened-before relation, these messages are delivered in their sending order to each process of the group. Even though prot... | Introduction
Asynchrony of communication channels is one of the major causes of nondeterminism in distributed
systems. The concept of causal ordering of messages has been introduced in the context of broadcasting
communication by Birman and Joseph [8] in order to reduce such an asynchrony. Causal
ordering means if two ... | sliding windows;causal broadcasting;happened-before relation;distributed systems;group communication;asynchrony;vector times |
298300 | Algebraic and Geometric Tools to Compute Projective and Permutation Invariants. | AbstractThis paper studies the computation of projective invariants in pairs of images from uncalibrated cameras and presents a detailed study of the projective and permutation invariants for configurations of points and/or lines. Two basic computational approaches are given, one algebraic and one geometric. In each ca... | Introduction
Various visual or visually-guided robotics tasks may be carried out using only a
projective representation which show the importance of projective informations
at different steps in the perception-action cycle. We can mention here the obstacle
detection and avoidance [14], goal position prediction for visu... | indexation;uncalibrated stereo;grassmann-cayley algebra;projective reconstruction;projective and permutation invariants;cross ratio |
298503 | L-Printable Sets. | A language is L-printable if there is a logspace algorithm which, on input 1n, prints all members in the language of length n. Following the work of Allender and Rubinstein [SIAM J. Comput., 17 (1988), pp. 1193--1202] on P-printable sets, we present some simple properties of the L-printable sets. This definition of "L... | Introduction
. What is an easy set? Typically, complexity theorists view
easy sets as those with easy membership tests. An even stronger requirement might
be that there is an easy algorithm to print all the elements of a given length. These
"printable" sets are easy enough that we can efficiently retrieve all of the in... | context-free languages;sparse sets;kolmogorov complexity;ranking;l-isomorphisms;computational complexity;regular languages;logspace |
298506 | The Inverse Satisfiability Problem. | We study the complexity of telling whether a set of bit-vectors represents the set of all satisfying truth assignments of a Boolean expression of a certain type. We show that the problem is coNP-complete when the expression is required to be in conjunctive normal form with three literals per clause (3CNF). We also pro... | Introduction
. Logic deals with logical formulae, and more particularly with
the syntax and the semantics of such formulae, as well as with the interplay between
these two aspects [CK90]. In the domain of Boolean logic, for example, a Boolean
formula OE may come in a variety of syntactic classes-conjunctive normal form... | coNP-completeness;boolean satisfiability;model;computational complexity;polynomial-time algorithms |
298507 | On Syntactic versus Computational Views of Approximability. | We attempt to reconcile the two distinct views of approximation classes: syntactic and computational. Syntactic classes such as MAX SNP permit structural results and have natural complete problems, while computational classes such as APX allow us to work with classes of problems whose approximability is well understood... | Introduction
The approximability of NP optimization (NPO) problems has been investigated in the past via the definition
of two different types of problem classes: syntactically-defined classes such as MAX SNP, and
computationally-defined classes such as APX (the class of optimization problems to which a constant factor... | approximation algorithms;computational classes;computational complexity;local search;complete problems;polynomial reductions |
298555 | A Spectral Algorithm for Seriation and the Consecutive Ones Problem. | In applications ranging from DNA sequencing through archeological dating to sparse matrix reordering, a recurrent problem is the sequencing of elements in such a way that highly correlated pairs of elements are near each other. That is, given a correlation function f reflecting the desire for each pair of elements to ... | Introduction
. Many applied computational problems involve ordering a set
so that closely coupled elements are placed near each other. This is the underlying
problem in such diverse applications as genomic sequencing, sparse matrix envelope
reduction and graph linear arrangement as well as less familiar settings such a... | consecutive ones property;eigenvector;analysis of algorithms;fiedler vector;seriation |
298560 | New Collapse Consequences of NP Having Small Circuits. | We show that if a self-reducible set has polynomial-size circuits, then it is low for the probabilistic class ZPP (NP). As a consequence we get a deeper collapse of the polynomial-time hierarchy PH to ZPP(NP) under the assumption that NP has polynomial-size circuits. This improves on the well-known result in Karp and L... | Introduction
. The question of whether intractable sets can be efficiently
decided by non-uniform models of computation has motivated much work in structural
complexity theory. In research from the early 1980's to the present, a variety of results
has been obtained showing that this is impossible under plausible assump... | polynomial-size circuits;lowness;advice classes;randomized computation |
298690 | Optimal Parallel Algorithms for Finding Proximate Points, with Applications. | AbstractConsider a set P of points in the plane sorted by x-coordinate. A point p in P is said to be a proximate point if there exists a point q on the x-axis such that p is the closest point to q over all points in P. The proximate point problem is to determine all the proximate points in P. Our main contribution is t... | Introduction
Consider a parallel algorithm that solves an instance of size n of some problem in T p (n) time
using p processors. Traditionally, the main complexity measure for assessing the performance of
Work supported in part by NSF grant CCR-9522093, by ONR grant N00014-97-1-0526, and by Grant-in-Aid for
Encourageme... | parallel algorithms;proximate points;digital geometry;convex hulls;pattern recognition;largest empty circles;cellular systems;image analysis |
298705 | Basic Operations on the OTIS-Mesh Optoelectronic Computer. | AbstractIn this paper, we develop algorithms for some basic operationsbroadcast, window broadcast, prefix sum, data sum, rank, shift, data accumulation, consecutive sum, adjacent sum, concentrate, distribute, generalize, sorting, random access read and writeon the OTIS-Mesh [1] model. These operations are useful in the... | Introduction
The Optical Transpose Interconnection System ( OTIS ), proposed by Marsden et al. [4], is a hybrid
optical and electronic interconnection system for large parallel computers. The OTIS architecture
space optics to connect distant processors and electronic interconnect to connect
nearby processors. Specifica... | optoelectronic;random access write;distribute;adjacent sum;random access read;prefix sum;OTIS-Mesh;concentrate;data accumulation;window broadcast;consecutive sum;sorting;broadcast;data sum;generalize;shift |
298770 | Co-Evolution in the Successful Learning of Backgammon Strategy. | Following Tesauros work on TD-Gammon, we used a 4,000 parameter feedforward neural network to develop a competitive backgammon evaluation function. Play proceeds by a roll of the dice, application of the network to all legal moves, and selection of the position with the highest evaluation. However, no backpropagation, ... | Introduction
It took great chutzpah for Gerald Tesauro to start wasting computer cycles on temporal
difference learning in the game of Backgammon (Tesauro, 1992). Letting a machine
learning program play itself in the hopes of becoming an expert, indeed! After all, the
dream of computers mastering a domain by self-play ... | coevolution;reinforcement;temporal difference learning;self-learning;backgammon |
298803 | Locality Analysis for Parallel C Programs. | AbstractMany parallel architectures support a memory model where some memory accesses are local and, thus, inexpensive, while other memory accesses are remote and potentially quite expensive. In the case of memory references via pointers, it is often difficult to determine if the memory reference is guaranteed to be lo... | Introduction
One of the key problems in parallel processing is to provide
a programming model that is simple for the pro-
grammer. One would like to give the programmer a
familiar programming language, and have the programmer
focus on high-level aspects such as coarse-grain parallelism
and perhaps some sort of static o... | compiling for parallel architectures;locality analysis;multithreaded architectures |
298815 | An Index-Based Checkpointing Algorithm for Autonomous Distributed Systems. | AbstractThis paper presents an index-based checkpointing algorithm for distributed systems with the aim of reducing the total number of checkpoints while ensuring that each checkpoint belongs to at least one consistent global checkpoint (or recovery line). The algorithm is based on an equivalence relation defined betwe... | Introduction
Checkpointing is one of the techniques for providing
fault-tolerance in distributed systems [6]. A global check-point
consists of a set of local checkpoints, one for each pro-
cess, from which a distributed computation can be restarted
after a failure. A local checkpoint is a state of a process
saved on st... | checkpointing;rollback-recovery;performance evaluation;global snapshot;distributed systems;timestamp management;causal dependency;fault tolerance;protocols |
298827 | Dynamically Configurable Message Flow Control for Fault-Tolerant Routing. | AbstractFault-tolerant routing protocols in modern interconnection networks rely heavily on the network flow control mechanisms used. Optimistic flow control mechanisms, such as wormhole switching (WS), realize very good performance, but are prone to deadlock in the presence of faults. Conservative flow control mechani... | Introduction
Modern multiprocessor interconnection networks feature the use of message pipelining coupled
with virtual channels to improve network throughput and insure deadlock freedom
[6,9,21,24]. Messages are broken up into small units called flits or flow control digits [9]. In
wormhole switching (WS), data flits i... | multiphase routing;multicomputer;fault-tolerant routing;pipelined interconnection network;message flow control;virtual channels;wormhole switching;routing protocol |
299336 | Vexillary Elements in the Hyperoctahedral Group. | In analogy with the symmetric group, we define the vexillary elements in the hyperoctahedral group to be those for which the Stanley function is a single Schur Q-function. We show that the vexillary elements can be again determined by pattern avoidance conditions. These results can be extended to include the root syste... | Introduction
The vexillary permutations in the symmetric group have interesting connections with
the number of reduced words, the Littlewood-Richardson rule, Stanley symmetric func-
tions, Schubert polynomials and the Schubert calculus. Lascoux and Sch-utzenberger [14]
have shown that vexillary permutations are charact... | stanley symmetric function;reduced word;hyperoctahedral group;vexillary |
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