ppxscal/embedding_network huggingface dataset:
Sentence paraphrasing from a conceptual base
Authors: Neil M. Goldman
Venue: Communications of the ACM (1975)

A model of natural language generation based on an underlying language-free representation of meaning is described. A program based on this model is able to produce sentence paraphrases which demonstrate understanding with respect to a given context. This generator operates in conjunction with a natural language analyzer and a combined memory and inference model. In generating sentences from meaning structures, the program employs both the information retrieval and deduction capabilities of the memory model. The model encompasses several diverse classes of linguistic knowledge, which include: (1) executable tests of conceptual properties stored in discrimination nets; (2) information relating conceptual to syntactic roles, stored in a word-sense dictionary, and (3) surface grammatical knowledge, stored in a formal grammar.
A Spatio-Frequency Trade-Off Scale for Scale-Space Filtering
Authors: Luc Florack
Venue: IEEE Transactions on Pattern Analysis and Machine Intelligence (2000)

We study implementation issues for spatial convolution filters and their Fourier alternative, with the aim to optimize the accuracy of filter output. We focus on Gaussian scale-space filters and show that there exists a trade-off scale that subdivides the available scale range into two subintervals of equal length. Below this trade-off scale Fourier filtering yields more accurate results than spatial filtering; above it is the other way around. This should be contrasted with demands of computational speed, which show the opposite tenet.
Parallelization of a Dynamic Unstructured Algorithm Using Three Leading Programming Paradigms
Authors: Leonid Oliker, Rupak Biswas
Venue: IEEE Transactions on Parallel and Distributed Systems (2000)

The success of parallel computing in solving real-life computationally intensive problems relies on their efficient mapping and execution on large-scale multiprocessor architectures. Many important applications are both unstructured and dynamic in nature, making their efficient parallel implementation a daunting task. This paper presents the parallelization of a dynamic unstructured mesh adaptation algorithm using three popular programming paradigms on three leading supercomputers. We examine an MPI message-passing implementation on the Cray T3E and the SGI Origin2000, a shared-memory implementation using the cache coherent nonuniform memory access (CC-NUMA) feature of the Origin2000, and a multithreaded version on the newly released Tera Multithreaded Architecture (MTA). We compare several critical factors of this parallel code development, including runtime, scalability, programmability, portability, and memory overhead. Our overall results demonstrate that multithreaded systems offer tremendous potential for quickly and efficiently solving some of the most challenging real-life problems on parallel computers.
The C31 parallel benchmark suite - introduction and preliminary results
Authors: Rakesh Jha, Richard C. Metzger, Brian VanVoorst, Luiz S. Pires, Wing Au, Minesh Amin, David A. Castanon, Vipin Kumar
Venue: Proceedings of the 1996 ACM/IEEE conference on Supercomputing (CDROM) (1996)

Current parallel benchmarks, while appropriate for scientific applications, lack the defense relevance and representativeness for developers who are considering parallel computers for their Command, Control, Communication, and Intelligence (C3I) systems. We present a new set of compact application benchmarks which are specific to the C3I application domain. The C3I Parallel Benchmark Suite (C3IPBS) program is addressing the evaluation of not only machine performance, but also the software implementation effort. Our methodology currently draws heavily from the PARKBENCH[2] and NAS Parallel Benchmarks[1]. The paper presents the benchmarking methodology, introduces the benchmarks, and reports initial results and analysis. Finally, we describe the lessons that we have learned so far from formulating and implementing the C3I benchmarks.
A Combinatorial Optimization Technique for the Sequential Decomposition of Erosions and Dilations
Authors: Ronaldo Fumio Hashimoto, Junior Barrera, Carlos Eduardo Ferreira
Venue: Journal of Mathematical Imaging and Vision (2000)

This paper presents a general algorithm for the automatic proof that an erosion (respectively, dilation) has a sequential decomposition or not. If the decomposition exists, an optimum decomposition is presented. The algorithm is based on a branch and bound search, with pruning strategies and bounds based on algebraic and geometrical properties deduced formally. This technique generalizes classical results as Zhuang and Haralick, Xu, and Park and Chin, with equivalent or improved performance. Finally, theoretical analysis of the proposed algorithm and experimental results are presented.
Efficient and small representation of line arrangements with applications
Authors: David P. Dobkin, Ayellet Tal
Venue: Proceedings of the seventeenth annual symposium on Computational geometry (2001)

This paper addresses the problem of lossy compression of arrangements. Given an arrangement of $n$ lines in the plane, we show how to construct another arrangement consisting of many fewer lines. We give theoretical and empirical bounds to demonstrate the tradeoffs between the size of the new arrangement and the error from lossiness.For the specific application of computing discrepancies of point sets, we demonstrate that speedups by factors of several hundred are possible while introducing small errors. This research has been enabled by various visualization techniques and is accompanied by a video.
Pattern width at a given angle
Authors: Allen Klinger
Venue: Communications of the ACM (1971)

That the pattern feature &ldquo;width as a function of angle&rdquo; possesses several possible interpretations is demonstrated in this paper, which is a review of the width concept in pattern recognition and the geometrical concept itself. The object of the work is to clarify how the word description can be made precise so that computer algorithms for feature extraction may be obtained; the focus is on theoretical subject matter. The results consist of a set-theoretic definition of width-at-angle, a theorem relating it to the pattern boundary radius vector, and descriptions of alternate widths. All widths are calculated for an illustrative example; graphical and tabular comparisons are given. Substantial variation in width-at-angle magnitude is found. The principal conclusion is that the set-theoretic width-at-angle is a useful pattern feature when it can be easily computed. Further investigation of the information contained in only part of a width function is recommended for cases where computation of width-at-angle is difficult.
Recursion analysis for compiler optimization
Authors: Kenneth G. Walter
Venue: Communications of the ACM (1976)

A relatively simple method for the detection of recursive use of procedures is presented for use in compiler optimization. Implementation considerations are discussed, and a modification of the algorithm is given to further improve optimization. This analysis can also be used to determine what possible subset of values could be assumed by variables which can only take on a relatively small discrete set of values. The most common are parameters of variables assuming values of label, procedure, or Pascal's enumerated type.
Design of the S system for data analysis
Authors: Richard A. Becker, John M. Chambers
Venue: Communications of the ACM (1984)

S is a language and system for interactive data analysis and graphics. It emphasizes interactive analysis and graphics, ease of use, flexibility, and extensibility. While sharing many characteristics with other statistical systems, S differs significantly in its design goals, its implementation, and the way it is used. This paper presents some of the design concepts and implementation techniques in S and relates these general ideas in computing to the specific design goals for S and to other statistical systems.
Improving Error Bounds for Multipole-Based Treecodes
Authors: Ananth Grama, Vivek Sarin, Ahmed Sameh
Venue: SIAM Journal on Scientific Computing (1999)

Rapid evaluation of potentials in particle systems is an important, time-consuming step in many physical simulations. Over the past decade, the development of treecodes, such as the fast multipole method and Barnes--Hut method, has enabled large scale simulations in astrophysics, molecular dynamics, material science, etc. These methods use fixed-degree polynomial approximations of the potential at a point, due to a set of particles in a hierarchical representation of the particle system. In this paper, we present analysis and experiments to illustrate that fixed-degree multipole approximations can lead to large aggregate errors. We describe an alternate strategy based on careful selection of the multipole degree that leads to asymptotically lower errors while incurring minimal computation overhead. First, we estimate the error associated with each particle-cluster interaction and the aggregate error for each particle. Then we describe a technique for computing the multipole degree of each interaction with a view to reducing aggregate error, and establish the computational complexity of the new method. Following this, we discuss numerical experiments that demonstrate favorable error properties of the new method at the expense of marginal increase in computation. Finally, we report a parallel implementation on the SGI Origin 2000 that achieves excellent speedup for problems from domains such as astrophysics and boundary element solvers.
Robbers, marshals, and guards: game theoretic and logical characterizations of hypertree width
Authors: Georg Gottlob, Nicola Leone, Francesco Scarcello
Venue: Proceedings of the twentieth ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems (2001)

In a previous paper [10], the authors introduced the notion of hypertree decomposition and the corresponding concept of hypertree width and showed that the conjunctive queries whose hypergraphs have bounded hypertree-width can be evaluated in polynomial time. Bounded hypertree-width generalizes the notions of acyclicity and bounded treewidth and corresponds to larger classes of tractable queries. In the present paper, we provide natural characterizations of hypergraphs and queries having bounded hypertree-width in terms of game-theory and logic. First we define the Robber and Marshals game, and prove that a hypergraph H has hypertree-width at most k iff k marshals have a winning strategy on H, allowing them to trap a robber who moves along the hyperedges. This game is akin the well-known Robber and Cops game (which characterizes bounded treewidth), except that marshals are more powerful than cops: They can control entire hyperedges instead of just vertices. Kolaitis and Vardi [17] recently gave an elegant characterization of the conjunctive queries having treewidth < k in terms of the k-variable fragment of a certain logic L ( = existential-conjunctive fragment of positive FO). We use the Robber and Marshals game to derive a surprisingly simple and equally elegant characterization of the class HW[k] of queries of hypertree-width at most k in terms of guarded logic. In particular, we show that HW[k] = GFk (L), where GFk(L) denotes the k-guarded fragment of L. In this fragment, conjunctions of k atoms rather than just single atoms are allowed to act as guards. Note that, for the particular case k = 1, our results provide new characterizations of the class of acyclic queries. We extend the notion of bounded hypertreewidth to nonrecursive stratified datalog and show that the k-guarded fragment GFk(FO) of first order logic has the same expressive power as nonrecursive stratified datalog of hypertreewidth &lne; k.
A general purpose data entry program
Authors: Jonathan P. Jacky, Ira J. Kalet
Venue: Communications of the ACM (1983)

Simulations constitute an important family of computer applications in science and engineering. To perform each simulation run, it is usually necessary to provide extensive data specifying the parameters of the simulation as well as data which support the calculation models involved. We have designed a program and a file structure that provides a method for convenient data entry, and creates and edits data files according to specifications contained in a separate file that serves as a template. By providing different templates, the same program can be made to serve numerous applications. The structure of the data files allows a degree of flexibility difficult to achieve using conventional database systems.
Difference Sets in Z_4^m and F_2^2m
Authors: Jacques Wolfmann
Venue: Designs, Codes and Cryptography (2000)

Let { R}=GR(4,m) be the Galois ring of cardinality 4^m and let { T} be the Teichm&uuml;ller system of { R}. For every map \lambda of { T} into \lbrace -1,+1\rbrace and for every permutation \pi of { T}, we define a map \phi_{\lambda}^{\pi} of { R} into \lbrace -1,+1\rbrace as follows: if x\in { R} and if x=a+2b is the 2-adic representation of x with a\in{ T} and b\in{ T}, then \phi_{\lambda}^{\pi}(x)=\lambda(a)+2Tr(\pi(a)b), where Tr is the trace function of { R} . For i=1 or i=-1, define D_i as the set of x in { R} such that\phi_{\lambda}^{\pi}=i . We prove the following results: 1) D_i is a Hadamard difference set of ({ R},+). 2) If \Phi is the Gray map of { R} into \F_2^{2m}, then \Phi(D_i) is a difference set of (\F_2^{2m},+). 3) The set of D_i and the set of \Phi(D_i) obtained for all maps \lambda and \pi, both are one-to-one image of the set of binary Maiorana-McFarland difference sets in a simple way. We also prove that special multiplicative subgroups of { R} are difference sets of kind D_i in the additive group of { R}. Examples are given by means of morphisms and norm in { R}.
Fixed-word-length arrays in variable-word-length computers
Authors: John A. Sonquiest
Venue: Communications of the ACM (1962)

Scientific users of small-scale variable-word-length computers, such as the IBM 1401, may frequently have the occasion to use fixed-word-length arrays. For instance, it is common practice to store matrices row-wise in linear arrays. A linear array whose elements are addresses is a common storage allocation scheme for handling pushdown lists. The ACM Portal is published by the Association for Computing Machinery. Copyright © 2010 ACM, Inc. Terms of Usage Privacy Policy Code of Ethics Contact Us Useful downloads: Adobe Acrobat QuickTime Windows Media Player Real Player
First-Order System Least Squares for the Stokes and Linear Elasticity Equations: Further Results
Authors: Z. Cai, C.-O. Lee, T. A. Manteuffel, S. F. McCormick
Venue: SIAM Journal on Scientific Computing (1999)

First-order system least squares (FOSLS) was developed in [ SIAM J. Numer. Anal., 34 (1997), pp. 1727--1741; SIAM J. Numer. Anal., 35 (1998), pp. 320--335] for Stokes and elasticity equations. Several new results for these methods are obtained here. First, the inverse-norm FOSLS scheme that was introduced but not analyzed in [ SIAM J. Numer. Anal., 34 (1997), pp. 1727--1741] is shown to be continuous and coercive in the L2 norm. This result is shown to hold for pure displacement or pure traction boundary conditions in two or three dimensions, and for mixed boundary conditions in two dimensions. Next, the FOSLS schemes developed in [ SIAM J. Numer. Anal., 35 (1998), pp. 320--335] are applied to the pure displacement problem in planar and spatial linear elasticity by eliminating the pressure variable in the FOSLS formulations of [SIAM J. Numer. Anal., 34 (1997), pp. 1727--1741]. The idea of two-dimensional variable rotation is then extended to three dimensions to make the intervariable coupling subdominant (uniformly so in the Poisson ratio for elasticity). This decoupling ensures optimal (uniform) performance of finite element discretization and multigrid solution methods. It also allows special treatment of the new trace variable, which corresponds to the divergence of velocity in the case of Stokes, so that conservation can be easily imposed, for example. Numerical results for various boundary value problems of planar linear elasticity are studied in a companion paper [SIAM J. Sci. Comput., 21 (2000), pp. 1706--1727].
Simultaneous events and lookahead in simulation protocols
Authors: Vikas Jha, Rajive Bagrodia
Venue: ACM Transactions on Modeling and Computer Simulation (TOMACS) (2000)

A discrete event simulation model may contain several events that have the same timestamp, referred to as simultaneous events. In general, the results of a simulation depend on the order in which simultaneous events are executed. Simulation languages and protocols use different, sometimes ad hoc, tie-breaking mechanisms to order simulataneous events. As a result, it may be impossible to reproduce the results of a simulation model across different simulators. This article presents a systematic analysis of the lookahead requirements for sequential and parallel simulation protocols, utilizing the process-oriented world view, with respect to their abililty to execute models with simultaneous events in a deterministic order. In particular, the article shows that most protocols, including the global event list protocol and commonly used parallel conservative and optimistic protocols, require that the simulation model provide some form of lookahead guarantee to enforce deterministc ordering of simultaneous events. The article also shows that the lookahead requirements for many protocols can be weakened if the model allows simultaneous events to be processed in a nondeterministic order. Finally, the lookahead properties that must be satisfied by a model in order for its execution to make guaranteed progress are derived using various simulation protocols.
Application of computer technologies for industrial development and protection of carpathians
Authors: Nestor Bybliuk, Oleg Styranivskiy
Venue: Proceedings of the symposium on Contemporary computing in Ukraine (2000)

In article a directed methods of ecological estimation of technological logging processes with use of computer GIS-technologies allows to face out fast spatial analysis and prognostication of change of natural conditions and ecological state of woodsy massif, perfection estimation and economic expediency of technological operations and technical logging methods with visual effect. Executed researches bear out fitness of this methods for reception of officient administrative decisions from logging technology choice, planning of network of woodsy roads on level of woodsy enterprise or his structural subsection.
An application of FORMAC
Authors: L. D. Neidleman
Venue: Communications of the ACM (1967)

A nonlinear circuit analysis problem is stated and the way in which it was solved using FORMAC is indicated. The solution of the problem using FORMAC was notable since several other methods that were tried failed. The problem is straightforward (although untenable by hand) but nevertheless involved an elaborate use of the FORMAC language. The program was fairly large and utilized practically every command. In particular, it made extensive use of the PART command. Several tricks were necessary in order to circumvent some of the shortcomings of the FORMAC system. This paper is more concerned with the use of programming techniques in FORMAC than with the actual engineering problem, although readers may be interested in the problem because it is stated in a general (mathematical) sense and could be of interest in areas other than circuit analysis.
Experience with a space efficient way to store a dictionary
Authors: Robert Nix
Venue: Communications of the ACM (1981)

The paper, &ldquo;Computer Programs for Detecting and Correcting Spelling Errors&rdquo; by James L. Peterson [3], listed methods for checking and correcting spelling errors. One significant method, however, was not included: a probabilistic technique suggested by Carter, Floyd, Gill, Markovsky, and Wegman [1]. The present note discusses aspects of these practical space efficient algorithms for testing set membership&mdash;a simple abstraction of looking a word up in a dictionary. An implementation of one of these algorithms uses only 20 percent of the space used by the Stanford SPELL program described by Peterson.
A bounded storage algorithm for copying cyclic structures
Authors: J. M. Robson
Venue: Communications of the ACM (1977)

A new algorithm is presented which copies cyclic list structures using bounded workspace and linear time. Unlike a previous similar algorithm, this one makes no assumptions about the storage allocation system in use and uses only operations likely to be available in a high-level language. The distinctive feature of this algorithm is a technique for traversing the structure twice, using the same spanning tree in each case, first from left to right and then from right to left.
Note on an anomaly in paging
Authors: John E. Pomeranz
Venue: Communications of the ACM (1970)

In [1] the authors use a lemma to prove their Theorem 1 (pp. 352-353). While the lemma is true, there is a defect in its proof, for one cannot assume that each of the symbols appearing as a type IV reference is in t(Ek , s). Using their example (p. 350) as a reference string with k = 12, t(E12 , 3) is 534 and lacks the two symbols (1 and 2) which appear as type IV references.
Implementing Clenshaw-Curtis quadrature, I methodology and experience
Authors: W. Morven Gentleman
Venue: Communications of the ACM (1972)

Clenshaw-Curtis quadrature is a particularly important automatic quadrature scheme for a variety of reasons, especially the high accuracy obtained from relatively few integrand values. However, it has received little use because it requires the computation of a cosine transformation, and the arithmetic cost of this has been prohibitive. This paper is in two parts; a companion paper, &ldquo;II Computing the Cosine Transformation,&rdquo; shows that this objection can be overcome by computing the cosine transformation by a modification of the fast Fourier transform algorithm. This first part discusses the strategy and various error estimates, and summarizes experience with a particular implementation of the scheme.
Analysis of the Functional Block Involved in the Design of Radial Basis Function Networks
Authors: I. Rojas, H. Pomares, J. Gonzáles, J. L. Bernier, E. Ros, F. J. Pelayo, A. Prieto
Venue: Neural Processing Letters (2000)

The main architectures, learning abilities and applications of radial basis function (RBF) neural networks are well documented. However, to the best of our knowledge, no in-depth analyses have been carried out into the influence on the behaviour of the neural network arising from the use of different alternatives for the design of an RBF (different non-linear functions, distances, number of neurons, structures, etc.). Thus, as a complement to the existing intuitive knowledge, it is necessary to have a more precise understanding of the significance of the different alternatives. In the present contribution, the relevance and relative importance of the parameters involved in such a design are investigated by using a statistical tool, the ANalysis Of the VAriance (ANOVA). In order to obtain results that are widely applicable, various problems of classification, functional approximation and time series estimation are analyzed. Conclusions are drawn regarding the whole set.