ppxscal/embedding_network huggingface dataset:
DC parallelism of connection graph
Authors: R. Loganantharaj
Venue: Proceedings of the 1987 Fall Joint Computer Conference on Exploring technology: today and tomorrow (1987)

In general, theorem provers are relatively slow. Speed up can be achieved by directing the search towards finding a proof and by using parallelism. In this paper we discuss dc parallel link resolution of connection graph refutation. In dc parallelism, the links (edges) incident to distinct clauses are resolved in parallel. Concurrent resolution of dc links may result in missing links between resolvents. The previous solutions of the missing link problem are not satisfactory: one leads to an indefinite wait and the other one restricts the dc links and therefore reducing the amount of parallelism available when applied with strategies and heuristics. We provide a solution to the missing link problem that will not restrict the dc links or not lead to an indefinite wait. We also provide the correctness of our parallel algorithms. A proof procedure using dc parallelism is outlined and an efficient method to obtain very promising dc links towards finding the empty clause is also described. In all the algorithms, we used the conventional parallel constructs. Finally, we describe the realization of the parallel constructs with an Encore Multimax (a tightly coupled multiprocessor) primitives.
The Balance Multiprocessor System
Authors: Shreekant Thakkar, Paul Gifford, Gary Fielland
Venue: IEEE Micro (1988)

A description is given of the architecture, operating system, and performance of Balance, a shared-memory, tightly coupled multiprocessor system. Balance can contain two to thirty 32-bit microprocessors with an aggregate performance of up to 21 million instructions per second (MIPS). Each processor has a private cache as well as a small local memory to hold frequently used kernel routines. The system features a high-bandwidth pipelined bus, up to 28 Mbytes of main memory, a diagnostic and console processor, up to four IEEE 769 (Multibus) adapters, an IEEE 802.3 (Ethernet) LAN interface, and an ANSI Small Computer System Interface (SCSI). Dynix, a multiprocessor operating system supporting both the 4.2 BSD and System V Unix environments, manages Balance, providing transparent support for multiprocessing as well as tools and libraries for developing parallel applications. The various subsystems and the Dynix operating system are examined. Applications and performance are discussed.
Incomplete Hypercubes
Authors: Howard P. Katseff
Venue: IEEE Transactions on Computers (1988)

Since a k-dimensional hypercube has 2/sup k/ vertices, these systems are restricted to having exactly 2/sup k/ computing nodes. Because system sizes must be a power of two, there are large gaps in the sizes of systems that can be built with hypercubes. Routing and broadcast algorithms are presented for hypercubes that are missing certain of their nodes, called incomplete hypercubes. Unlike hypercubes, incomplete hypercubes can be used to interconnect systems with any number of processors. The routing and broadcast algorithms for incomplete hypercubes are shown also to be simple and deadlock-free.
Computer literacy and the older learner: a computer department's response
Authors: Jerry Maren
Venue: ACM SIGCSE Bulletin (1987)

As a computer science educator it is personally gratifying to learn of the success achieved by former students as they experience the thrill of accomplishment in their first computer related job. However, the student who shared one such experience with me last summer was uniquely different from the typical college student. She was over 55" and back to work for the first time in 25 years. Mastery of word processing and spreadsheet software applications had led to her placement in a job employing those skills. Her employer s pleasure with the high quality of her work was as much a joy to me as it was to her. Six months prior to that day she had never worked on a computer and had no thought of doing so. Her progress and subsequent success, as well as that of 15 other older workers, has motivated this article, as well as additional computer training classes for the older workers in our community.
An Empirical Study of Distributed Application Performance
Authors: K. A. Lantz, William I. Nowicki, Marvin M. Theimer
Venue: IEEE Transactions on Software Engineering (1985)

A major reason for the rarity of distributed applications, despite the proliferation of networks, is the sensitivity of their performance to various aspects of the network environment. We demonstrate that distributed applications can run faster than local ones, using common hardware. We also show that the primary factors affecting performance are, in approximate order of importance: speed of the user's workstation, speed of the remote host (if any), and the high-level (above the transport level) protocols used. In particular, the use of batching, pipelining, and structure in high-level protocols reduces the degradation often experienced between different bandwidth networks. Less significant, but still noticeable improvements result from proper design and implementation of the underlying transport protocols. Ultimately, with proper application of these techniques, network bandwidth is rendered virtually insignificant.
Dealing with disparate audiences in computer science courses using a project group within a traditional class
Authors: R. Waldo Roth, Arthur White
Venue: Proceedings of the eighteenth SIGCSE technical symposium on Computer science education (1987)

A frequent problem in advanced computer science courses is having students enrolled in a single class whose backgrounds range from upper division students with significant work experience to sophomores who have completed only a few computer science courses. This paper proposes a solution to this problem by combining a research project for those advanced students within a traditional course for the remaining enrollees. Although the specific course dealt with in this instance is data communications, it is believed that the model proposed is transportable to other advanced courses in computer science which have students with varied backgrounds.
Express&mdash;rapid prototyping and product development via integrated knowledge-based executable specifications
Authors: P. Topping, J. McInroy, W. Livley, S. Sheppard
Venue: Proceedings of the 1987 Fall Joint Computer Conference on Exploring technology: today and tomorrow (1987)

A knowledge based software development environment under development at Lockheed's Software Technology Center (STC) in Austin, Texas. The environment, called Express, consists of several very high level executable specification languages, their corresponding translation systems, and a knowledge based framework to integrate and manage the specifications both at specification time and execution time. Express generates code automatically via a series of correctness-preserving transformations on the specifications. The ultimate effect is a dramatic increase in software development productivity and maintainability. This paper provides an overview of the environment and highlights the development of the Graphical Specification Subsystem which is the component of the environment for prototyping the interface between the target user and the embedded system interface.
Random sampling with a reservoir
Authors: Jeffrey S. Vitter
Venue: ACM Transactions on Mathematical Software (TOMS) (1985)

We introduce fast algorithms for selecting a random sample of n records without replacement from a pool of N records, where the value of N is unknown beforehand. The main result of the paper is the design and analysis of Algorithm Z; it does the sampling in one pass using constant space and in O(n(1 + log(N/n))) expected time, which is optimum, up to a constant factor. Several optimizations are studied that collectively improve the speed of the naive version of the algorithm by an order of magnitude. We give an efficient Pascal-like implementation that incorporates these modifications and that is suitable for general use. Theoretical and empirical results indicate that Algorithm Z outperforms current methods by a significant margin.
Performance analysis of several back-end database architectures
Authors: Robert Brian Hagmann, Domenico Ferrari
Venue: ACM Transactions on Database Systems (TODS) (1986)

The growing acceptance of database systems makes their performance increasingly more important. One way to gain performance is to off-load some of the functions of the database system to aback-end computer. The problem is what functions should be off-loaded to maximize the benefits of distributed processing. Our approach to this problem consisted of constructing several variants of an existing relational database system. INGRES, that partition the database system software into two parts, and assigning these two parts to two computers connected by a local area network. For the purposes of this experiment, six different variants of the database software were constructed to test the sir most interesting functional subdivisions. Each variant was then benchmarked using two different databases and query streams. The communication medium and the communication software were also benchmarked to measure their contribution to the performance of each configuration. Combining the database and network measurement results, various conclusions were reached about the viability of the configurations, the desirable properties of the communications mechanisms to he used, the operating system interface and overhead, and the performance of the database system. The variants to be preferred depend on the hardware technology, operating system features, database system internal structure, and network software overhead.
An analysis of length equation using a dynamic approach
Authors: T Y Chen, S C Kwan
Venue: ACM SIGPLAN Notices (1986)

This paper is to compare the dynamic and static approaches towards the analysis of the length equation, which is the most fundamental and important equation in the theory of software science. In addition to intuition, our empirical results give further support to the claim that dynamic approach is more appropriate than the static approach towards the theory of software science.
Specification and verification of liveness properties of cyclic, concurrent processes
Authors: Joylyn Reed, Raymond T. Yeh
Venue: ACM Transactions on Programming Languages and Systems (TOPLAS) (1988)

A technique is described for software specification and verification of concurrent, distributed systems. The complete specification of a program is given in terms of a hierarchical structure of module specifications. Module external specifications are abstract; module internal specifications are descriptions of internal implementations, either in terms of submodules or actual code. The verification that an implementation satisfies its specification is language independent for the former and language dependent for the latter. Distinguishing the liveness properites provided by a module and the liveness properties required by a module (from its comodules) allows the specification and verification of a given module to be independent from the specification and verification of its comodules.
An Algorithm for Geometric Set Operations Using Cellular Subdivision Techniques
Authors: Ingrid Carlbom
Venue: IEEE Computer Graphics and Applications (1987)

Geometric set operations play an integral role in systems for CAD/CAM, for robot planning, and for modeling objects such as underground formations from empirical data. Two major issues in the implementation of geometric set operations are efficiency in the search for geometric intersections and effectiveness in the treatment of singular intersection cases. This article presents an algorithm for geometric set operations on planar polyhedral nonmanifold objects that addresses both these issues. First, an efficient search for geometric intersections is obtained by localizing the search to small regions of object space through a cellular subdivision scheme using the polytree data structure. Second, an effective treatment of singular intersection cases is obtained by mapping each singular intersection occurring in a region into one of a small set of cases.
On the consistency assumption, monotone criterion and the monotone restriction
Authors: James B. H. Kwa
Venue: Issue 103 (Jan., 1988) (1988)

Hitherto, the consistency assumption has been deemed to be strong and it suffices for the purposes of proving certain important properties of the A* algorithm to use either of two weaker versions, viz. monotone criterion and monotone restriction. Here, we show that the opposite is true -- the consistency assumption is not only weaker, but sufficient. Moreover, it implies admissibility.
Unification in combinations of collapse-free regular theories
Authors: Katherine A. Yelick
Venue: Journal of Symbolic Computation (1987)

This paper presents a method for combining equational unification algorithms to handle terms containing 'mixed' sets of function symbols. For example, given one algorithm for unifying associative-commutative operators, and another for unifying commutative operators, our algorithm provides a method for unifying terms containing both kinds of operators. As a special case of the combining problem, our algorithm lifts a variable-only case algorithm to the general case with multiple operator instances and free symbols. We restrict our attention to a class of equational theories called the collapse-free regular theories. We give some results characterizing the unification problem in this class of theories, and specifically show the restrictions are necessary and sufficient for the correctness of our algorithm. An implementation has been done as part of a larger system for reasoning about equational theories.
The Illinois functional programming interpreter
Authors: A. D. Robison
Venue: ACM SIGPLAN Notices (1987)

The Illinois Functional Programming (IFP) language is a modified version of Backus' FP(1). IFP has the same side-effect free combinator style of Backus FP, while introducing an ALGOL-like syntax and structure. While IFP superficially appears to be an inefficient language to execute, its simplicity makes it quick to interpret. Functions are always monadic and there are no variable or parameter names. Furthermore, combinator-style languages allow common housekeeping operations to be condensed into efficient machine-language primitives.By reference-counting, the interpreter can often convert call-by-value to destructive call-by-reference while preserving referential transparency. The interpreter has an expression cache which can improve the asymptotic time of some combinatorial functions. IFP function definitions are stored as UNIX files, so much of UNIX's functionality is immediately borrowed into the IFP environment, e.g. ls, more, and grep.Benchmarks indicate that IFP is an order of magnitude faster than Berkeley FP[2], and is competitive with interpreted von-Neumann languages such as BASIC. The interpreter can parallel process on shared-memory multiprocessors, e.g. the Encore Multimax. IFP currently runs on machines as varied as the IBM PC, VAX, and CRAY-XMP.
Supporting office document architectures with constrained types
Authors: W. B. Croft, D. W. Stemple
Venue: ACM SIGMOD Record (1987)

Data models have been proposed as a means of defining the objects and operations in an office information system. Office documents, because of their highly variable structure and multimedia content, are a difficult class of objects to model. The modeling task is further complicated by document architecture standards used for interchange between systems. We present an approach to data modeling based on constrained type definitions that allows architecture standards to be defined and ensures that individual document types conform to those standards. The ADABTPL model, which is used to define the schema of document types and standards, is described.
A two-bit contention-based TDMA technique for data transmissions
Authors: D Tsai, J Chang
Venue: Proceedings of the ACM SIGCOMM conference on Communications architectures protocols (1986)

The performance of a contention-based TDMA technique is studied in this paper. The frame structure of the time-axis is similar to [1] and [2]. The protocols proposed in [1],[2] and here are all active multiaccess techniques. The protocol in [1] is contention free and suitable for heavy traffic while a contention-based protocol suitable for light traffic is considered in [2]. The protocol to be studied in this paper is also contention in nature and performs considerably better than [2]. This protocol is less complicated than [1] and out-performs [1] unless traffic is very high. Performance analyses, both transient and steady-state, have been successfully completed. Results obtained include average queue length and packet delay, etc. The validity of analysis is also verified by computer simulations.
Compiler Optimizations for Enhancing Parallelism and Their Impact on Architecture Design
Authors: C. D. Polychronopoulos
Venue: IEEE Transactions on Computers (1988)

By examining the structure and characteristics of parallel programs the author isolates potential overhead sources. The first compiler optimization considered is cycle shrinking which can be used to parallelize certain types of serial loops. A run-time dependence analysis is then considered along with how it can be performed through compiler-inserted bookkeeping and control statements. Loops with unstructured parallelism, that cannot benefit from existing optimizations, can be parallelized through run-time dependence checking. Finally, barrier synchronization is discussed as one of the most serious sources of run-time overhead in parallel programs. To reduce the impact of barriers, the author briefly discusses the implementation of distributed barriers through the use of a set of shared registers.
PARIS: a system for reusing partially interpreted schemas
Authors: S. Katz C. A. Richter, K.-S. The
Venue: Proceedings of the 9th international conference on Software Engineering (1987)

This paper describes PARIS, an implemented system that facilitates the reuse of partially interpreted schemas. A schema is a program and specification with abstract, or uninterpreted, entities. Different interpretations of those entities will produce different programs. The PARIS System maintains a library of such schemas and provides an interactive mechanism to interpret a schema into a useful program by means of partially automated matching and verification procedures.
Free-form deformation of solid geometric models
Authors: Thomas W. Sederberg, Scott R. Parry
Venue: ACM SIGGRAPH Computer Graphics (1986)

A technique is presented for deforming solid geometric models in a free-form manner. The technique can be used with any solid modeling system, such as CSG or B-rep. It can deform surface primitives of any type or degree: planes, quadrics, parametric surface patches, or implicitly defined surfaces, for example. The deformation can be applied either globally or locally. Local deformations can be imposed with any desired degree of derivative continuity. It is also possible to deform a solid model in such a way that its volume is preserved.The scheme is based on trivariate Bernstein polynomials, and provides the designer with an intuitive appreciation for its effects.
An Algorithm to Decide Feasibility of Linear Integer Constraints Occurrng in Decision Tables
Authors: S. Biswas, V. Rajarman
Venue: IEEE Transactions on Software Engineering (1987)

To detect errors in decision tables one needs to decide whether a given set of constraints is feasible or not. This paper describes an algorithm to do so when the constraints are linear in variables that take only integer values. Decision tables with such constraints occur frequently in business data processing and in nonnumeric applications. The aim of the algorithm is to exploit. the abundance of very simple constraints that occur in typical decision table contexts. Essentially, the algorithm is a backtrack procedure where the the solution space is pruned by using the set of simple constrains. After some simplications, the simple constraints are captured in an acyclic directed graph with weighted edges. Further, only those partial vectors are considered from extension which can be extended to assignments that will at least satisfy the simple constraints. This is how pruning of the solution space is achieved. For every partial assignment considered, the graph representation of the simple constraints provides a lower bound for each variable which is not yet assigned a value. These lower bounds play a vital role in the algorithm and they are obtained in an efficient manner by updating older lower bounds. Our present algorithm also incorporates an idea by which it can be checked whether or not an (m -2)-ary vector can be extended to a solution vector of m components, thereby backtracking is reduced by one component.
Disaligning macro, meso and micro due process: a case study of office automation in Quebec colleges
Authors: Francois Blanchard, Alberto Cambrosio
Venue: Proceedings of the ACM SIGOIS and IEEECS TC-OA 1988 conference on Office information systems (1988)

By drawing on recent studies of computing in the interactionist tradition, and more particularly on the notion of due process, the paper presents a case study of the introduction of office automation in Quebec colleges. Failures to reach negotiated agreements about conflicting representations of ongoing work processes in software systems are categorized by actors as problems of &ldquo;fitting&rdquo;, i.e. of achieving a satisfactory balance between needs and technology. Representations of what constitutes an &ldquo;appropriate fit&rdquo; are accompanied by representations of the appropriate organizational level at which a &ldquo;good fit&rdquo; may be attained. In our study, this has resulted in the displacement over time of the locus of software design. The disalignment of levels of work organization appears to be a central part of the work of achieving a temporary closure of the due process problem and should be taken into account when attempting to provide computational solutions to this problem.
Interface design: a neglected issue in educational software
Authors: Douglas Frye, Elliot Soloway
Venue: ACM SIGCHI Bulletin (1987)

The user interface is particularly important for educational software because 1) it must provide an entry to the content domain of the program rather than vice versa and 2) it must be sensitive to the general skill and/or developmental level of the user. In spite of these special characteristics, interface design for educational software has been given little attention. This study evaluates a representative interface from arithmetic software now used in the schools. It was found that the interface caused students a large number of difficulties. These difficulties were sufficient to interfere with the instructional effectiveness of the software. Designing interfaces that will benefit educational software will require careful study of the users of these programs along with an in-depth understanding of the domains being taught.
Inverter-Minimum Networks
Authors: K. Nakamura
Venue: IEEE Transactions on Computers (1987)

Let Fm= (f1,...,fm) be a vector of m logical functions. Let Inv (Fm), the inversion complexity of Fm, be the minimum number of inverters required to realize Fm by a feed-forward network using AND gates, OR gates, and inverters.