ppxscal/embedding_network huggingface dataset:
New methods for computing visibility graphs
Authors: M. H. Overmars, E. Welzl
Venue: Proceedings of the fourth annual symposium on Computational geometry (1988)

Let S be a set of n non-intersecting line segments in the plane. The visibility graph GS of S is the graph that has the endpoints of the segments in S as nodes and in which two nodes are adjacent whenever they can &ldquo;see&rdquo; each other (i.e., the open line segment joining them is disjoint from all segments or is contained in a segment). Two new methods are presented to construct GS. Both methods are very simple to implement. The first method is based on a new solution to the following problem: given a set of points, for each point sort the other points around it by angle. It runs in time &Ogr;(n2). The second method uses the fact that visibility graphs often are sparse and runs in time &Ogr;(m log n) where m is the number of edges in GS. Both methods use only Ogr;(n) storage.
Meta-circular interpreter for a strongly typed language
Authors: Masami Hagiya
Venue: Journal of Symbolic Computation (1989)

A functional language is introduced, whose type system is defined by its meta-circular interpreter. The functional language is an extension of @l-calculus augmented with the rule for conditional terms that allows the condition of a conditional term to be used for reducing its branches. This makes it possible to deduce the well-typing of terms with dependent types including the meta-circular interpreter. In the type system built by the interpreter, types are represented by ordinary terms, which reflects the recent object-oriented programming languages, in which classes are manipulated as ordinary objects. The paper first discusses the untyped system of the functional language and its consistency, then develops the representation of types and the representation of terms, and define a meta-circular interpreter, by which the well-typing of the language is defined and also discusses the extensibility of the interpreter and the type system.
DEBL: a knowledge-based language for specifying and debugging programs
Authors: W.-H. S. Cheug, V. E. Wallentine
Venue: Proceedings of the 17th conference on ACM Annual Computer Science Conference (1989)

This paper describes a knowledge-based language-DEBL which integrates specification and debugging features for distributed programs. It provides programming language independent facilities which makes it adaptable to different programming environments. The semantics of DEBL is based on a temporal logic system which enhances DEBL with rigorous deduction power. The items in the knowledge-base form a hierarchy in which higher level and more complex logical concepts are constructed from lower and simpler ones.
Data intensive production systems: the DIPS approach
Authors: T. Sellis, C. Lin, L. Raschid
Venue: ACM SIGMOD Record (1989)

In this paper we highlight the basic approach taken in the design of the DIPS system, and briefly present the main contributions. These include the use of special data structures to store rule definitions; they are implemented using relations. A matching algorithm uses these structures to efficiently identify when the antecedents of productions are satisfied, making them applicable for execution. Partial match information stored in the data structures is used by the matching algorithm. We also describe a proposed concurrent execution strategy for applicable productions, which surpasses in performance, the traditional sequential OPS5 production execution algorithm. The requirements for a correct, serializable execution, based on locking, is described. An advantage of the matching technique in DIPS is that it is fully parallelizable, which makes it attractive for implementation in parallel computing environments.
A computer assisted optimal depth lower bound for sorting networks with nine inputs
Authors: I. Parberry
Venue: Proceedings of the 1989 ACM/IEEE conference on Supercomputing (1989)

It is demonstrated that there is no nine-input sorting network of depth six. The proof was obtained by executing on a supercomputer a branch-and-bound algorithm which constructs and tests a critical subset of all possible candidates. Such proofs can be classified as experimental science, rather than mathematics. In keeping with the paradigms of experimental science, a high-level description of the experiment and analysis of the result are given.
Three-dimensional numerical simulations of the czochralski bulk flow on a CRAY X-MP multiprocessor architecture
Authors: W. E. Nagel, K. Wingerath
Venue: Proceedings of the 2nd international conference on Supercomputing (1988)

Today, numerical simulation is used more and more to get detailed information about crystal growth processes. In the Czochralski crystal growth from electrically conductive melts, the application of an external magnetic field has become a very useful technique for improving crystal quality. The integration of the magnetic field into the simulation program leads to a system of coupled partial differential equations, i.e. incompressible Navier-Stokes equations and convective heat equations in combination with an external magnetic field, which have to be solved. Because of the regular access to data this problem is suitable for vector computers. The CRAY X-MP provides vectorization and multiprocessing capabilities. With multitasking it is possible to run different parts of one program in parallel. Both multitasking concepts, macrotasking and microtasking, were examined to evaluate their potential to speed-up the Czochralski crystal growth simulation program implemented on a CRAY X-MP. We will give a survey of the application, and will describe the concepts of macrotasking and microtasking on the CRAY X-MP architecture as well as the integration of these concepts into the simulation program. Timing results provide information about the user benefit obtained by using these techniques.
On prolog and the occur check problem
Authors: K. Marriott, H. Sondergaard
Venue: ACM SIGPLAN Notices (1989)

It is well-known that omission of the occur check in unification leads to unsound Prolog systems. Nevertheless, most Prolog systems omit the occur check because this makes unification much faster and unsoundness allegedly seldom manifests itself. We revisit the occur check problem and point to two aspects that have previously received no attention. Firstly, "unification without the occur check" is ambiguous, and in practice, Prolog systems vary markedly in their reaction to programs having occur check problems. Secondly, even very simple program transformations are unsafe for pure Prolog when the occur check is omitted. We conclude that the occur check problem is important, and in particular, that the current efforts to standardize Prolog should address it.
A rule network for efficient implementation of a mixed-initiative reasoning scheme
Authors: G. Biswas, X. Yu
Venue: Proceedings of the 17th conference on ACM Annual Computer Science Conference (1989)

MIDST (Mixed Inferencing Dempster Shafer Tool) is a rule-based expert system shell that incorporates mixed-initiative reasoning and uncertain reasoning based on the Dempster-Shafer evidence combination scheme. This paper discusses the design and implementation of a rule network for MIDST that facilitates an efficient implementation of the mixed-initiative reasoning scheme.
A methodology for parallelizing programs for multicomputers and complex memory multiprocessors
Authors: J. Ramanujam, P. Sadayappan
Venue: Proceedings of the 1989 ACM/IEEE conference on Supercomputing (1989)

The availability of large distributed memory multiprocessors and parallel computers with complex memory hierarchies have left the programmer with the difficult task of planning the detailed parallel execution of a program; for example, in the case of distributed memory machines, the programmer is forced to manually distribute code and data in addition to managing communication among tasks explicitly. Current work in compiler support for this task has focused on automating task partitioning, assuming a fixed data partition or a programmer-specified (in the form of annotations) data partition. This paper argues that one of the reasons for inefficient parallel execution is the lack of synergism between task partitioning and data partitioning and allocation; hence data and task allocation should both be influenced by the inherent dependence structure of the computation (which is the source of synergism). We present a methodology based on a unified approach to task and data partitioning; we show how to derive data and task partitions for computations expressed as nested loops that exhibit regular dependencies and how to map these onto distributed memory multiprocessors. Based on the mapping, we show how to derive code for the nodes of a distributed memory machine with appropriate message transmission constructs. We also discuss related communication optimizations.
Polling: a new randomized sampling technique for computational geometry
Authors: J. H. Reif, S. Sen
Venue: Proceedings of the twenty-first annual ACM symposium on Theory of computing (1989)

We introduce a new randomized sampling technique, called Polling which has applications to deriving efficient parallel algorithms. As an example of its use in computational geometry, we present an optimal parallel randomized algorithm for intersection of half-spaces in three dimensions. Because of well-known reductions, our methods also yield equally efficient algorithms for fundamental problems like the convex hull in three dimensions, Voronoi diagram of point sites on a plane and Euclidean minimal spanning tree. Our algorithms run in time T = O(logn) for worst-case inputs and uses P = O(n) processors in a CREW PRAM model where n is the input size. They are randomized in the sense that they use a total of only O(log2 n) random bits and terminate in the claimed time bound with probability 1 - n-&agr; for any &agr; > 0. They are also optimal in P . T product since the sequential time bound for all these problems is &OHgr;(nlogn). The best known determistic parallel algorithms for 2-D Voronoi-diagram and 3-D Convex hull run in O(log2 n) and O(log2 nlog * n) time respectively while using O(n) processors.
Resource management in a distributed internetwork environment
Authors: G. Skinner, J. M. Wrabetz, Louis Schreir
Venue: Proceedings of the ACM workshop on Frontiers in computer communications technology (1987)

The resource management system is designed to support location-transparent access to resources and to improve performance in a distributed internetwork environment. In this environment, access to one of several machines that have a given resource is determined by the effective bandwidth and reliability of internetwork communications, the ability to interact with the machines offering the resources, and the load on those machines. Using these criteria, the resources management system enables applications to determine and obtain access to the &ldquo;best&rdquo; copy of a resource. Should the resource become unavailable from one machine, the resource management system can dynamically direct the applications to another machine known to offer the same resource. This paper discusses some of the problems that motivated the design, an implementation for a UNIX workstation environment, and future directions for the resource management system.
Survey and comparison of PARLOG and Concurrent Prolog
Authors: D. Talia
Venue: ACM SIGPLAN Notices (1990)

The integration of logic programming and concurrent programming has created a new class of languages, concurrent logic languages. These languages are born from a new interpretation of Horn clauses, called the process interpretation. The main goal of concurrent logic languages is the exploitation of parallelism which is inside logic programs. Furthermore, they extend the application areas of logic programming. This paper surveys and compares the two most significant concurrent programming languages, PARLOG and Concurrent Prolog. For both languages the main features are presented and discussed.
The effective use of undergraduates to staff large introductory CS courses
Authors: Stuart Reges, John McGrory, Jeff Smith
Venue: ACM SIGCSE Bulletin (1988)

In the past few years many schools have tried to simultaneously achieve the following goals in their introductory CS courses: Allow more students to enroll Improve the quality of education Keep spending at current levels Everyone has discovered that the first two goals are difficult to achieve in the presence of the third. This paper presents a model that has evolved over the last five years at Stanford University where all three goals have been accomplished by replacing graduate student TAs with undergraduate section leaders.
Mathematical formula editor for CAI
Authors: Yasutomo Nakayama
Venue: Proceedings of the SIGCHI conference on Human factors in computing systems: Wings for the mind (1989)

Many students in lower grades who study mathematics with computers have difficulty in inputting formulas by using existing methods. It would be much easier for them if they could input formulas naturally, as they appear in textbooks. This paper describes such an interface program module for use in CAI. This module makes it easy for students to input and edit complex formulas solely by key operations, without using a mouse. The difference between the module and existing mathematical expression editors is that it converts formulas into character strings syntactically. In this way, CAI programs can understand the meanings of the formulas.
Limits on multiple instruction issue
Authors: M. D. Smith, M. Johnson, M. A. Horowitz
Venue: ACM SIGARCH Computer Architecture News (1989)

This paper investigates the limitations on designing a processor which can sustain an execution rate of greater than one instruction per cycle on highly-optimized, non-scientific applications. We have used trace-driven simulations to determine that these applications contain enough instruction independence to sustain an instruction rate of about two instructions per cycle. In a straightforward implementation, cost considerations argue strongly against decoding more than two instructions in one cycle. Given this constraint, the efficiency in instruction fetching rather than the complexity of the execution hardware limits the concurrency attainable at the instruction level.
Computer-aided derivation of spherical harmonic spectral equations in astrogeophysics
Authors: M. L. Dudley, R. W. James
Venue: Journal of Symbolic Computation (1989)

The numerical solution of mathematical problems in global astrogeophysics is often based on spherical harmonic spectral analysis of the governing partial differential equations. We report here on successful applications of the computer algebra programs MACSYMA, MAPLE and REDUCE for the generation of spectral equations associated with the magnetic induction equation, one of the fundamental vector equations involved in modelling magnetohydrodynamic interactions in the Earth's core, stellar atmospheres and stellar interiors. This application indicates that computer algebra programs will be a powerful tool for deriving spherical harmonic spectral equations for partial differential equations in mathematical physics.
Six-digit coding method
Authors: Jinan Qiao Yizheng Qiao, Sanzheng Qiao
Venue: Communications of the ACM (1990)

The Six-Digit Coding Method (SDCM) is a new coding method for Chinese characters. It is based on the structural analysis of Chinese characters. We recently developed this method and have successfully used it to code 11,100 characters, including the simplified, traditional, and variant forms found in Xin Hua Dictionary [7]. This article illustrates the basic principes, features, and some viewpoints concerning the method.
Continuation-passing, closure-passing style
Authors: A. W. Appel, T. Jim
Venue: Proceedings of the 16th ACM SIGPLAN-SIGACT symposium on Principles of programming languages (1989)

We implemented a continuation-passing style (CPS) code generator for ML. Our CPS language is represented as an ML datatype in which all functions are named and most kinds of ill-formed expressions are impossible. We separate the code generation into phases that rewrite this representation into ever-simpler forms. Closures are represented explicitly as records, so that closure strategies can be communicated from one phase to another. No stack is used. Our benchmark data shows that the new method is an improvement over our previous, abstract-machine based code generator.
The impact of structured editing on introductory computer science education: the results so far
Authors: D. R. Goldenson
Venue: ACM SIGCSE Bulletin (1989)

Properly done, introductory computer science courses have great potential, both for preparing future computing professionals and for the broad goals of general education. Yet the performance all too often lags well behind the promise. Poor grades, high failure and drop out rates are all too common at both the collegiate and pre-collegiate levels. However the advent of seamless programming environments based on structure editing provides us with an opportunity to change the situation in fundamental ways. Initial studies show dramatic differences between students who do and do not use a structure editor based environment.
Logic simulation on massively parallel architectures
Authors: S. Kravitz, R. E. Bryant, R. Rutenbar
Venue: ACM SIGARCH Computer Architecture News (1989)

This work examines the mapping of logic simulation onto massively parallel computer architectures. We discuss alternative communication primitives for a massively parallel instruction set architecture and the impact of the choice of communication primitives on logic simulation. We have developed compilation tools to automatically map the simulation of an MOS transistor circuit onto a massively parallel computer. We analyze the efficiency of this mapping as a function of the available communication primitives. The compilation process is illustrated by describing our pilot implementation on a 32k processor Connection Machine.
Information retrieval using a singular value decomposition model of latent semantic structure
Authors: G. W. Furnas, S. Deerwester, S. T. Dumais, T. K. Landauer, R. A. Harshman, L. A. Streeter, K. E. Lochbaum
Venue: Proceedings of the 11th annual international ACM SIGIR conference on Research and development in information retrieval (1988)

In a new method for automatic indexing and retrieval, implicit higher-order structure in the association of terms with documents is modeled to improve estimates of term-document association, and therefore the detection of relevant documents on the basis of terms found in queries. Singular-value decomposition is used to decompose a large term by document matrix into 50 to 150 orthogonal factors from which the original matrix can be approximated by linear combination; both documents and terms are represented as vectors in a 50- to 150- dimensional space. Queries are represented as pseudo-documents vectors formed from weighted combinations of terms, and documents are ordered by their similarity to the query. Initial tests find this automatic method very promising.
Curve-to-curve associations in spline-based inbetweening and sweeping
Authors: R. H. Bartel, R. T. Hardock
Venue: ACM SIGGRAPH Computer Graphics (1989)

We are concerned in this paper with associations between spline curves that will hold at all inbetween positions when the control points of these curves are used as key points for animation or sweeping. It is established that any association between two spline curves that can be expressed as the equality of two linear mappings will hold throughout an inbetweening process provided the inbetweening trajectories are coordinated splines that uniquely interpolate the control-point key positions. Multiple associations are possible, so long as the basic requirements of linearity and coordination are observed.
What is EuroParc?
Authors: T. P. Moran
Venue: ACM SIGCHI Bulletin (1989)

EuroPARC is a systems research laboratory supported by Rank Xerox Limited and allied with the Xerox Palo Alto Research Center (PARC). The decision to create EuroPARC was announced in November of 1986, and the lab was officially dedicated in June of 1988. EuroPARC's research charter is human-computer interaction. The research program is coordinated with PARC's, but the goal is to combine PARC-style systems research with European points of view, issues, and approaches.
The computer construction of matrix representationsof finite groups over finite fields
Authors: R. A. Parker, R. A. Wilson
Venue: Journal of Symbolic Computation (1990)

Given an abstract group G it is important to be able to find explicit generators for a concretegroup isomorphic to G, in order to perform calculations with the group. In this paper we describe a method of using the ''Meat-axe'' to construct explicit matrix generators for a given group.
SIMS: a uniform environment for planning and performing user's tasks
Authors: Jasmina Pavlin, Raymond L. Bates
Venue: Proceedings of the 1st international conference on Industrial and engineering applications of artificial intelligence and expert systems - Volume 1 (1988)

SIMS is an environment which greatly reduces the burden of planning and performing tasks involving multiple diverse software servers. The user interacts with SIMS in the language natural for the task domain, which is independent of available services. Two main functions of SIMS are task planning and execution. Planning is the main focus of the paper. Planning is supported by the knowledge about domain terminology, models of tasks and of the functionality of servers. Tasks and servers can be modeled in SIMS in different levels of detail. More detailed models enable more efficient search for services relevant for the task. Search is also limited by the hierarchical structure of knowledge. Besides helping users, SIMS gives a methodology for building more maintainable systems by providing the language for specifying server functionality and a principled method for modifying the system when services are modified.
Texture Boundary Detection Based on the Long Correlation Model
Authors: R. L. Kashyap, K.-B. Eom
Venue: IEEE Transactions on Pattern Analysis and Machine Intelligence (1989)

The problem of detecting texture boundaries without assuming any knowledge on the number of regions or the types of textures is considered. Texture boundaries are often regarded as better features than intensity edges, because a large class of images can be considered a composite of several different texture regions. An algorithm is developed that detects texture boundaries at reasonably high resolution without assuming any prior knowledge on the texture composition of the image. The algorithm utilizes the long correlation texture model with a small number of parameters to characterize textures. The parameters of the model are estimated by a least-squares method in the frequency domain. The existence and the location of texture boundary is estimated by the maximum-likelihood method. The algorithm is applied to several different images, and its performance is shown by examples. Experimental results show that the algorithm successfully detects texture boundaries without knowing the number of types of textures in the image.