ppxscal/embedding_network huggingface dataset:
Modelling Waves with Computer Algebra
Authors: D. A. Diver
Venue: Journal of Symbolic Computation (1991)

A sophisticated model for linear waves in an inhomogeneous plasma is tackled completely using the computer algebra system REDUCE. The algebra code mirrors the mathematics, and is structured in a simple and straightforward manner. In so doing, the solution technique is made obvious, and the overall philosophy of the approach is intuitive to the non-specialist computer algebra user.
Reveng: a cost-effective approach to reverse-engineering
Authors: Xavier A. Debest, Rüdiger Knoop, Jürgen Wagner
Venue: ACM SIGSOFT Software Engineering Notes (1992)

Like many other Software Engineering buzzwords, "Reverse Engineering" emerges as an attempt to formalize some specific tasks, which have long been performed by almost every software development or maintenance team, but which were not judged worth before to be considered an engineering discipline. The emergence of powerful Computer Aided Software Engineering (CASE) tools opens new opportunities for the cost-effective re-use of the investments made in existing software systems, and thus for the development of specific tools and techniques to recover the original design of these systems.While most of the current discussion is centered around the development and utilization of tools to automate the Reverse Engineering Process, our attention focuses on the practical application of these tools and techniques under conditions found in real world entreprises. From this view-point, the scope of the Reverse Engineering Techniques appears to be much broader than implied by the characteristics of individual tools.Our approach is based on experiences gained by CMG in projects, either directly related to Reverse Engineering or dealing with tasks, where specific Reverse Engineering Techniques and Tools were advantageously used (e.g. Software Maintenance, Re-Design, Down-Sizing, Conversion). It also evidentiates some pitfalls, which may lead to the failure of some Reverse Engineering projects.
An object-oriented kernel for an integrated design and process planning system
Authors: S. J. Feghhi, M. Marefat, R. L. Kashyap
Venue: Proceedings of the 27th ACM/IEEE Design Automation Conference (1991)

An object-oriented kernel that integrates design and process planning in the domain of mechanical parts is presented. The kernel has identified and separated the integral elements of its domain from the elements that are associated with a particular design/manufacturing environment. Consequently, it can be customized to a wide range of environments and be used as a rapid prototyping tool. A prototype has been developed and implemented in Smalltalk-80.
Unification of underlying concepts in different office models
Authors: Sandhya M. Desai
Venue: ACM SIGMIS Database (1991)

Several office models based on different perspectives of offices have been published in the literature. Most of the models emphasize a particular aspect of an office and consequently do not capture all the nuances of offices. We study eight representative office models with regards to their expressive power and underlying concepts.From the set of concepts embedded in these models we arrive at a minimal set of three concepts, namely, office information, office work and office agents. These are the essential aspects to be captured in a model reflecting all the complexities of offices. Based on this minimal set, three basic entities -- object, activity and role -- are proposed. An outline of an office model in terms of its basic entities is presented. The existing models are analysed with reference to the characteristics of the basic entities.
N-Poisson document modelling
Authors: Eugene L. Margulis
Venue: Proceedings of the 15th annual international ACM SIGIR conference on Research and development in information retrieval (1992)

This paper is a report of a study investigating the validity of the Multiple Poisson (nP) model of word distribution in document collections. An nP distribution is a mixture of n Poisson distributions with different means. We describe a practical algorithm for determining if a certain word is distributed acording to an nP distribution and computing the distribution parameters. The algorithm was applied to every word in four different document collections. It was found that over 70% of frequently occurring words and terms indeed behave according to the nP distributions. The results indicate that the proportion of nP words depends on the collection size, document length and the frequency of the individual words. Most of the nP words recognised are distributed according to the mixture of relatively few single Poisson distributions (two, three or four). There is an indication that the number of single Poisson components in the mixture of relatively few single Poisson distributions (two, three or four). There is an indication that the number of single Poisson components in the mixture depends on the collection frequency of words.
Hierarchical Performance Evaluation Based on Formally Specified Communication Protocols
Authors: Elke Heck, Dieter Hogrefe, Bruno Müller-Clostmann
Venue: IEEE Transactions on Computers (1991)

Combining formal description techniques (FDTs) with performance evaluation (PE) is a requirement known from the 'single-specification/multiple-techniques' approach associated with the protocol engineering vision. The approach presented here assumes that a formally defined open systems interconnection (OSI) communication protocol can be syntactically transformed to a form suitable to a performance evaluation tool, and afterwards enhanced by implementation-dependence information on the protocol's resource requirements. Such a module, describing functional and performance behavior of the protocol, can then be embedded in a framework which allows its performance evaluation. This framework comprises an OSI-service provider as a transportation medium, processors providing computing services, and means for communication with the adjacent upper layer by use of associated input and output buffers. The present approach uses concepts from the performance evaluation tool HIT. Its applicability to OSI-communication architectures is sketched by means of the PE-modeling language HI-SLANG and the FD-language SDL.
Fault-tolerant computation in the full information model (extended abstract)
Authors: Oded Goldreich, Shafi Goldwasser, Nathan Linial
Venue: Proceedings of the 32nd annual symposium on Foundations of computer science (1991)

Efficient two-party protocols for fault-tolerant computation of any two-argument function are presented. It is proved that the influence of a dishonest player in these protocols is the minimum one possible (up to polylogarithmic factors). Also presented are efficient m-party fault-tolerant protocols for sampling a general distribution (m>or=2). Efficient m-party protocols for computation of any m-argument function are given, and it is proved for these protocols that for most functions, the influence of any t dishonest players on the outcome of the protocol is the minimum one possible (up to polylogarithmic factors).
Determining Reflectance Properties of an Object Using Range and Brightness Images
Authors: Katsushi Ikeuchi, Kosuke Sato
Venue: IEEE Transactions on Pattern Analysis and Machine Intelligence (1991)

The authors discuss a method of recovering reflectance properties of a surface from a range image given by a range finder and a brightness image given by a standard TV camera. The Torrance-Sparrow model is used for the reflectance model. The model consists of the Lambertian and specular components: its reflectance properties consist of the relative strength between the Lambertian and specular components and specular sharpness as well as light source direction. An iterative least square fitting method is used to obtain these parameters based on the range and brightness images. An input image is segmented into four different parts using the parameters: Lambertian reflection, specular reflection, interreflection, and shadow part. The authors also reconstruct ideal images that consist of only Lambertian or specular reflection.
A sequential abstract machine for a distributed logic language
Authors: José C. Cunha, Manuel B. Carvalhosa
Venue: Proceedings of the 1992 ACM annual conference on Communications (1992)

Delta Prolog is a concurrent logic programming language founded on the theoretical model of Distributed Logic and extending the Prolog language in order to allow the specification of concurrent systems. This paper describes Delta Prolog, its operational semantics and a sequential abstract machine (DAM) for the language.
Stability of block algorithms with fast level-3 BLAS
Authors: James W. Demmel, Nicholas J. Higham
Venue: ACM Transactions on Mathematical Software (TOMS) (1992)

Block algorithms are becoming increasingly popular in matrix computations. Since their basic unit of data is a submatrix rather than a scalar, they have a higher level of granularity than point algorithms, and this makes them well suited to high-performance computers. The numerical stability of the block algorithms in the new linear algebra program library LAPACK is investigated here. It is shown that these algorithms have backward error analyses in which the backward error bounds are commensurate with the error bounds for the underlying level-3 BLAS (BLAS3). One implication is that the block algorithms are as stable as the corresponding point algorithms when conventional BLAS3 are used. A second implication is that the use of BLAS3 based on fast matrix multiplication techniques affects the stability only insofar as it increases the constant terms in the normwise backward error bounds. For linear equation solvers employing LU factorization, it is shown that fixed precision iterative refinement helps to mitigate the effect of the larger error constants. Despite the positive results presented here, not all plausible block algorithms are stable; we illustrate this with the example of LU factorization with block triangular factors and describe how to check a block algorithm for stability without doing a full error analysis.
Scatter/Gather: a cluster-based approach to browsing large document collections
Authors: Douglass R. Cutting, David R. Karger, Jan O. Pedersen, John W. Tukey
Venue: Proceedings of the 15th annual international ACM SIGIR conference on Research and development in information retrieval (1992)

Document clustering has not been well received as an information retrieval tool. Objections to its use fall into two main categories: first, that clustering is too slow for large corpora (with running time often quadratic in the number of documents); and second, that clustering does not appreciably improve retrieval. We argue that these problems arise only when clustering is used in an attempt to improve conventional search techniques. However, looking at clustering as an information access tool in its own right obviates these objections, and provides a powerful new access paradigm. We present a document browsing technique that employs document clustering as its primary operation. We also present fast (linear time) clustering algorithms which support this interactive browsing paradigm.
Specifying metaphors algebraically
Authors: Werner Kuhn, Jeffrey P. Jackson, Andrew U. Frank
Venue: ACM SIGCHI Bulletin (1991)

A sound engineering approach to user interface design requires the formalization of key interaction concepts, one of them being metaphor. Few formal theories of metaphor exist and most of them have been developed in the context of natural language understanding, learning, or reasoning. Work on metaphors in human-computer interaction has been largely non-formal so far.
Algorithmic Synthesis of MVL Functions for CCD Implementation
Authors: Mostafa H. Abd-El-Barr, Zvonko G. Vranesic, Safwat G. Zaky
Venue: IEEE Transactions on Computers (1991)

Algorithms for synthesis of four-valued one- and two-variable functions for CCD (charge coupled device) implementation are proposed. One-variable synthesis is based on the observation that the cost of a realization of a function f(x) increases in the presence of breaks, or negative transitions, in the value of f as x increases. The function is decomposed to minimize the number of such transitions. Two-variable functions are synthesized as a sum of products of literals, taking advantage of literals that are easily implemented in CCD technology. It is concluded that the proposed algorithms perform better than those published previously.
When Computers Were Human
Authors: Paul E. Ceruzzi
Venue: IEEE Annals of the History of Computing (1991)

A memorandum dated April 27, 1942, from the National Advisory Committee for Aeronautics, is reproduced. The memorandum describes a computing facility at the Langley Memorial Aeronautical Laboratory, in which a team of humans equipped with mechanical calculators was organized to assist in aeronautics research. The memorandum reveals much about the state of computing as it existed just before the invention of automatic digital computers, whose introduction would bring this era to a close.
Fat triangles determine linearly many holes
Authors: Jiří Matoušek, Nathaly Miller, Micha Sharir, Shmuel Sifrony, János Pach, Emo Welzl
Venue: Proceedings of the 32nd annual symposium on Foundations of computer science (1991)

It is shown that for every fixed delta >0 the following holds: if F is a union of n triangles, all of whose angles are at least delta , then the complement of F has O(n) connected components, and the boundary of F consists of O(n log log n) segments. This latter complexity becomes linear if all triangles are of roughly the same size or if they are all infinite wedges. A randomized algorithm that computes F in expected time O(n2/sup alpha (n)/ log n) is given. Several applications of these results are presented.
An analysis of loop latency in dataflow execution
Authors: Walid A. Najjar, W. Marcus Miller, A. P. Wim Böhm
Venue: ACM SIGARCH Computer Architecture News (1992)

Recent evidence indicates that the exploitation of locality in dataflow programs could have a dramatic impact on performance. The current trend in the design of dataflow processors suggest a synthesis of traditional non-strict fine grain instruction execution and a strict coarse grain execution in order to exploit locality. While an increase in instruction granularity will favor the exploitation of locality within a single execution thread, the resulting grain size may increase latency among execution threads. In this paper, the resulting latency incurred through the partitioning of fine grain instructions to quantify coarse grain input and output latencies using a set of numeric benchmarks. The results offer compelling evidence that the inner loops of a significant number of numeric codes would benefit from coarse grain execution. Based on cluster execution times, more than 60% of the measured benchmarks favor a coarse grain execution. IN 64% of the cases the input latency to the cluster is the same in coarse or fine grain execution modes. The results suggest that the effects of increased instruction granularity on latency is minimal for a high percentage of the measured codes, and in large part is offset by available intra-thread locality. Furthermore, simulation results indicate that strict or non-strict data structure access does not change the basic cluster characteristics.
On the Detection of Motion and the Computation of Optical Flow
Authors: James H. Duncan, Tsai-Chia Chou
Venue: IEEE Transactions on Pattern Analysis and Machine Intelligence (1992)

A method for the detection of motion in image sequences is presented. In this method, the intensity history at each pixel is convolved with the second derivative in time of a temporal Gaussian smoothing function. The zero crossings in a single frame of the resulting function indicate the positions of moving edges. Intensity changes in time due to illumination effects do not produce zero crossings; thus, they are not interpreted as motion by the present method. It is also shown that the spatial and temporal derivatives of this function can be used to compute the component of the optical flow that is normal to the zero-crossing contours. This computation is also insensitive to nonconvective temporal and spatial variations in the image intensity that are caused by illumination effects.
The Dotted straightening algorithm
Authors: Tim Mcmillan, Neil L. White
Venue: Journal of Symbolic Computation (1991)

If a homogeneous bracket polynomial is antisymmetric in certain subsets of its points, then it can be represented in an abbreviated form called a dotted bracket expression. These dotted bracket expressions lead to a more compact expression in terms of tableaux than the usual representation. Consequently, we can derive a much more efficient straightening algorithm than the ordinary one for bracket polynomials already given in dotted form. This dotted straightening algorithm gives precisely the same result as the ordinary one, and preserves the dotted property at every step.
A compiler construction project for an object-oriented language
Authors: Mark C. Temte
Venue: Proceedings of the twenty-third SIGCSE technical symposium on Computer science education (1992)

A non-traditional compiler construction project is described for an object-oriented language modeled after Smalltalk. Central issues include implementation of message sending and inheritance and the relationship with the run-time environment. The project offers diversity and challenge and has been successfully completed by small teams.
From Invention to Production: The Development of Punched-card Machines by F. R. Bull and K. A. Knutsen 1918-1930
Authors: Lars Heide
Venue: IEEE Annals of the History of Computing (1991)

Punched-card machines were in a number of ways predecessors to computers. The punched-card technique was invented in the United States in the 1880s by Herman Hollerith, who continued development for another two decades. His firm later became the main component of IBM. Only two main competitors to Hollerith emerged, Powers in the United States and Bull first in Norway and later in France. This article covers the development of the Bull machines in the Norwegian period, 1918- 1930.
Deductive databases: achievements and future directions
Authors: Jeffrey D. Ullman, Carlo Zaniolo
Venue: ACM SIGMOD Record (1990)

In the recent years, Deductive Databases have been the focus of intense research, which has brought dramatic advances in theory, systems and applications. A salient feature of deductive databases is their capability of supporting a declarative, rule-based style of expressing queries and applications on databases. As such, they find applications in disparate areas, such as knowledge mining from databases, and computer-aided design and manufacturing systems. In this paper, we briefly review the key concepts behind deductive databases and their newly developed enabling technology. Then, we describe current research on extending the functionality and usability of deductive databases and on providing a synthesis of deductive databases with procedural and object-oriented approaches.
A comparison of four pseudo random number generators implemented in Ada
Authors: William N. Graham
Venue: ACM SIGSIM Simulation Digest (1992)

Four random number generators implemented in Ada are compared in terms of their equidistribution, independence, speed and period. Each generator is described and it's code presented. The tests used to evaluate the generators were simple ones. First, a stream of random numbers generated were checked for equidistribution by means of a chi-square test. Next, the numbers were checked for independence by means of a serial test. The code was then timed for a certain number of iterations. Finally, the reported periods of the generators are compared.
Fast text processing for information retrieval
Authors: Tomek Strzalkowski, Barabara Vauthey
Venue: Proceedings of the workshop on Speech and Natural Language (1991)

We describe an advanced text processing system for information retrieval from natural language document collections. We use both syntactic processing as well as statistical term clustering to obtain a representation of documents which would be more accurate than those obtained with more traditional key-word methods. A reliable top-down parser has been developed that allows for fast processing of large amounts of text, and for a precise identification of desired types of phrases for statistical analysis. Two statistical measures are computed: the measure of informational contribution of words in phrases, and the similarity measure between words.
Empirical investigation of knowledge representation servers: design issues and applications experience with KRS
Authors: Brain R. Gaines
Venue: ACM SIGART Bulletin (1991)

The design and application of KRS, a knowledge representation server in the KL-ONE, KRYPTON, CLASSIC family, are described. The server is designed as an open architecture module that can be used as a stand-alone service or embedded in other systems. It accepts the constraints necessary to make subsumption and recognition tractable, and maintains a careful distinction between definitions and assertions. It is implemented as a class library in an object-oriented language using generic, reusable objects. The approach taken to the integration of the server with external knowledge representation servers of similar or dissimilar types is analyzed. The server supports reasoning with exceptions and incomplete data through computation of a three-valued subsumption relation that is able to determine the possibility of further inferences if more assertions are made. KRS demonstrates that it is now possible to develop knowledge representation servers on a par with floating-point arithmetic units and numeric libraries, as modules with well-defined functionality and fast, reliable performance. It is also proving a useful tool for the empirical investigation of some large-scale knowledge representation server applications.
Distributed priority algorithms under one-bit-delay constraint
Authors: Reuven Cohen, Adrian Segall
Venue: Proceedings of the eleventh annual ACM symposium on Principles of distributed computing (1992)

The paper deals with the issue of station delay in token-ring networks. It explains why one-bit-delay is the minimum possible delay at every station and shows that the station delay depends on the distributed computations performed in the ring. Then, the paper introduces the distributed priority mechanism for token-rings, as approved by the IEEE-802.5 standard. This mechanism attaches to the token, that circulates around the ring and controls the access to the shared medium, a priority field P and a reservation field R. These two fields work together in an attempt to match the service priority of the ring to the highest priority message that is waiting to be sent. It is shown that due to the computation restrictions imposed by the one-bit-delay requirements, this priority mechanism has a grave deficiency as follows. When the token priority is higher than the maximum reservation (P > R), the token should make up to P round-trips, where P is the number of priority levels, before P is reduced to R. During this time period, no station may seize the token and send a message. This leads to loss of bandwidth. The paper presents a new priority mechanism that retains the desired properties of the standard. However, in the new protocol when P > R holds, P is reduced to R in at most 1 round-trip rather than in up to P round-trips.