ppxscal/embedding_network huggingface dataset:
Fast ray tracing by ray classification
Authors: James Arvo, David Kirk
Venue: Proceedings of the 14th annual conference on Computer graphics and interactive techniques (1987)

We describe a new approach to ray tracing which drastically reduces the number of ray-object and ray-bounds intersection calculations by means of 5-dimensional space subdivision. Collections of rays originating from a common 3D rectangular volume and directed through a 2D solid angle are represented as hypercubes in 5-space. A 5D volume bounding the space of rays is dynamically subdivided into hypercubes, each linked to a set of objects which are candidates for intersection. Rays are classified into unique hypercubes and checked for intersection with the associated candidate object set. We compare several techniques for object extent testing, including boxes, spheres, plane-sets, and convex polyhedra. In addition, we examine optimizations made possible by the directional nature of the algorithm, such as sorting, caching and backface culling. Results indicate that this algorithm significantly outperforms previous ray tracing techniques, especially for comples environments.
A microprogramming project for a course in computer systems
Authors: J. Archer Harris
Venue: ACM SIGCSE Bulletin (1988)

This paper describes a microprogramming project in a course in Computer Systems and Architecture. The project requires the students to write a machine language emulator on a simple microarchitecture. The limited scope of the machine language and the simplicity of the microarchitecture reduce the project to a manageable size. A simulator implements the microarchitecture, producing tracing output which allows students to follow the flow of their microprograms. The project and the simulator have proved to be a useful tools in teaching the concepts of emulation and microcoding.
Systems of linear equations with dense univariate polynomial coefficients
Authors: Stanley Cabay, Bart Domzy
Venue: Journal of the ACM (JACM) (1987)

An algorithm for computing the power series solution of a system of linear equations with components that are dense univariate polynomials over a field is described and analyzed. A method for converting the power series solution to rational form is derived. Theoretical and experimental cost estimates are obtained and used to identify classes of problems for which the power series method outperforms modular methods. Finally, it is shown that the power series method also provides an effective mechanism for solving the problem in which the coefficients of the polynomials are from the ring of integers.
Time warp operating system
Authors: D. Jefferson, B. Beckman, F. Wieland, L. Blume, M. Diloreto
Venue: Proceedings of the eleventh ACM Symposium on Operating systems principles (1987)

This paper describes the Time Warp Operating System, under development for three years at the Jet Propulsion Laboratory for the Caltech Mark III Hypercube multi-processor. Its primary goal is concurrent execution of large, irregular discrete event simulations at maximum speed. It also supports any other distributed applications that are synchronized by virtual time.The Time Warp Operating System includes a complete implementation of the Time Warp mechanism, and is a substantial departure from conventional operating systems in that it performs synchronization by a general distributed process rollback mechanism. The use of general rollback forces a rethinking of many aspects of operating system design, including programming interface, scheduling, message routing and queueing, storage management, flow control, and commitment.In this paper we review the mechanics of Time Warp, describe the TWOS operating system, show how to construct simulations in object-oriented form to run under TWOS, and offer a qualitative comparison of Time Warp to the Chandy-Misra method of distributed simulation. We also include details of two benchmark simulations and preliminary measurements of time-to-completion, speedup, rollback rate, and antimessage rate, all as functions of the number of processors used.
On the Height of Multidimensional Height-Balanced Trees
Authors: V K Vaishnavi
Venue: IEEE Transactions on Computers (1986)

It is shown that the worst case height of a k- dimensional height-balanced tree, k = 2, is the same as that of an AVL-tree, to within an additive factor of 2k - 2.
Bounds on Algorithm-Based Fault Tolerance in Multiple Processor Systems
Authors: Rrithviraj Banerjee, Jacob A. Abraham
Venue: IEEE Transactions on Computers (1986)

An important consideration in the design of high- performance multiple processor systems should be in ensuring the correctness of results computed by such complex systems which are extremely prone to transient and intermittent failures. The detection and location of faults and errors concurrently with normal system operation can be achieved through the application of appropriate on-line checks on the results of the computations. This is the domain of algorithm-based fault tolerance, which deals with low-cost system-level fault-tolerance techniques to produce reliable computations in multiple processor systems, by tailoring the fault-tolerance techniques toward specific algorithms. This paper presents a graph-theoretic model for determining upper and lower bounds on the number of checks needed for achieving concurrent fault detection and location. The objective is to estimate ate the overhead in time and the number of processors required for such a scheme. Faults in processors, errors in the data, and checks on the data to detect and locate errors are represented as a tripartite graph. Bounds on the time and processor overhead are obtained by considering a series of subproblems. First, using some crude concepts for t-fault detection and t-fault location, bounds on the maximum size of the error patterns that can arise from such fault patterns are obtained. Using these results, bounds are derived on the number of checks required for error detection and location. Some numerical results are derived from a linear programming formulation.
A RISC architecture for symbolic computation
Authors: Richard B. Kieburtz
Venue: ACM SIGARCH Computer Architecture News (1987)

The G-machine is a language-directed processor architecture designed to support graph reduction as a model of computation. It can carry out lazy evaluation of functional language programs and can evaluate programs in which logical variables are used. To support these language features, the abstract machine requires tagged memory and executes some rather complex instructions, such as to evaluate a function application.This paper explores an implementation of the G-machine as a high performance RISC architecture. Complex instructions can be represented by RISC code without experiencing a large expansion of code volume. The instruction pipeline is discussed in some detail. The processor is intended to be integrated into a standard, 32-bit memory architecture. Tagged memory is supported by aggregating data with tags in a cache.
On the evaluation strategy of EDUCE
Authors: Jorge Bocca
Venue: ACM SIGMOD Record (1986)

Educe is a logic programming system for handling large knowledge bases. It was constructed by fully integrating the logic programming language Prolog and the relational data base management system Ingres. Educe uses a hybrid strategy for the evaluation of queries. This strategy is based on two contrasting strategies. The strategy known as sets retrieval, transforms recursive and non-recursive queries into a form suitable for evaluation by a relational data base management system. The other strategy, known as one-tuple-at-a time, evaluates queries by imitating the evaluation strategy of the programming language Prolog. In earlier versions of Educe, users selected the strategy by using two different query languages. In order to remove this responsibility from the user, algorithms to map expressions from either of the languages into the other were implemented and added to Educe. This paper briefly reviews the implementation of both evaluators and the mappings compares the basic strategies of evaluation, and then proceeds to explain Educe's own strategy.
Organization of clustered files for consecutive retrieval
Authors: J S. Deogun, V V. Raghavan, T K.W. Tsou
Venue: ACM Transactions on Database Systems (TODS) (1984)

This paper studies the problem of storing single-level and multilevel clustered files. Necessary and sufficient conditions for a single-level clustered file to have the consecutive retrieval property (CRP) are developed. A linear time algorithm to test the CRP for a given clustered file and to identify the proper arrangement of objects, if CRP exists, is presented. For the single-level clustered files that do not have CRP, it is shown that the problem of identifying a storage organization with minimum redundancy is NP-complete. Consequently, an efficient heuristic algorithm to generate a good storage organization for such files is developed. Furthermore, it is shown that, for certain types of multilevel clustered files, there exists a storage organization such that the objects in each cluster, for all clusters in each level of the clustering, appear in consecutive locations.
Interprocessor Traffic Scheduling Algorithm for Multiple-Processor Networks
Authors: Jr, R. P. Bianchini, J. P. Shen
Venue: IEEE Transactions on Computers (1987)

Recent research on parallel systems has shown that the most difficult problem for system designers and users is interprocessor connection and communication. A methodology for the automated design and implementation of interprocessor communication for certain multiple-processor systems has been developed and is presented in this paper. For many application- specific and mission-oriented systems, the interprocessor communication is deterministic and can be specified at system inception. This specification can then be automatically mapped or complied onto a physical multiple-processor system using a network traffic scheduler. An algorithm for such a scheduler, which is capable of obtaining optimal network traffic patterns, has been developed. It is shown that the order of complexity of network scheduler components is polynomial, rather than expopential as in classical solutions.
Complexity and parallel processing: an interview with Richard Karp
Authors: Karen A. Frenkel
Venue: Communications of the ACM (1986)

In the following interview, which took place at ACM 85 in Denver, Karp discusses the relation of his work to leading-edge computing topics like parallel processing and artificial intelligence. Tracing his experience as a pioneer in highly theoretical computer science, Karp describes how the decision to go against established wisdom led to the work for which he is best known and how a colleague's findings led him to see links between two previously unrelated areas. Throughout, he stresses the exchange of ideas with colleagues that helped yield fundamental insights.
A microcode-based environment for noninvasive performance analysis
Authors: S. W. Melvin, Y. N. Patt
Venue: Proceedings of the 19th annual workshop on Microprogramming (1986)

We have developed an environment which allows us to collect data for performance analysis by modifying the microcode of a VAX 8600. This use of microprogramming permits data to be collected with minimal system perturbation (i.e. the data is almost as good as that obtained with a hardware monitor) but at the cost and with the ease of use of a software simulator. In this paper we describe the environment that we have developed and present two examples of its use. The first example, procedure call instrumentation, illustrates a technique for gathering data on how certain architectural features are used. The second example, instruction tracing, illustrates a technique for collecting data that can then be used in trace&mdash;driven simulation.
A natural language based legal expert system for consultation and tutoring&mdash;the LEX project
Authors: F. Haft, R. P. Jones, Th. Wetter
Venue: Proceedings of the 1st international conference on Artificial intelligence and law (1987)

The LEX (Legal Expert System) project is one of the European based projects investigating legal expert systems from both a professional and a teaching perspective. The project is a cooperative project between the University of T&uuml;bingen and IBM Germany and developed out of research into a User Specialty Language system (USL) for natural language queries to a relational data base. The LEX system has as its main components a Natural Language Analyzer for analysis and logic representation of written texts. A Knowledge Base holding; sources from the legal codes, explanations from legal commentaries, some common sense knowledge, and a lexicon of approximately 20000 words. Finally a Deductive Component based upon tableau calculus, conducts inference within the system. The system has as its primary aim to enable lawyers to input in natural language a set of case facts and to ask questions on the juridical issues connected to those facts. Dialogue is controlled enabling intelligent explanation to the user when required. A secondary aim is to provide additional components so as to enable the system to tutor on the legal domain held within the system. The development of the system has enabled the project team to gain insights into the problem of formalization of legal rules within the German legal system.
A survival strategy for APL
Authors: Dick Bowman
Venue: ACM SIGAPL APL Quote Quad (1987)

Echoing the concerns of the conference Call for Papers, APL no longer holds the market niche which it once had - over the past few years new developments in the world of computing have overtaken many of the areas which were once our exclusive province. Given that the computing industry is one which focuses hard on 'winners', we have to ask ourselves whether or not there is a long-term place for APL, what that place might be and how we can attain it. The contention of this paper is that an honorable future for APL can be found and that we can reach this position more easily if we work toward it together the exact path to be outlined here is not necessarily the 'correct' one but at the present stage of the game our most urgent need is to consider as many of the facts as we can muster.
Software quality and reliability basics
Authors: J. D. Musa
Venue: Proceedings of the 1987 Fall Joint Computer Conference on Exploring technology: today and tomorrow (1987)

The importance of software quality and the relationship of software reliability to software quality are discussed. The need for software reliability measures is demonstrated by outlining some possible applications. Basic software reliability concepts are presented, including software modeling.
A fourth-order-accurate Fourier method for the Helmholtz equation in three dimensions
Authors: Ronald F. Boisvert
Venue: ACM Transactions on Mathematical Software (TOMS) (1987)

We present fourth-order-accurate compact discretizations of the Helmholtz equation on rectangular domains in two and three dimensions with any combination of Dirichlet, Neumann, or periodic boundary conditions. The resulting systems of linear algebraic equations have the same block-tridiagonal structure as traditional central differences and hence may be solved efficiently using the Fourier method. The performance of the method for a variety of test cases, including problems with nonsmooth solutions, is presented. The method is seen to be roughly twice as fast as deferred corrections and, in many cases, results in a smaller discretization error.
Associative searching in multiple storage units
Authors: C. T. Wu, Walter A. Burkhard
Venue: ACM Transactions on Database Systems (TODS) (1987)

A file maintenance model, called the multiple random access storage units model, is introduced. Storage units can be accessed simultaneously, and the parallel processing of an associative query is achieved by distributing data evenly among the storage units. Maximum parallelism is obtained when data satisfying an associative query are evenly distributed for every possible query. An allocation scheme called M-cycle allocation is proposed to maintain large files of data on multiple random access storage units. The allocation scheme provides an efficient and straightforward indexing over multidimensional key spaces and supports the parallel processing of orthogonal range queries. Our analysis shows that M-cycle allocation achieves the near-optimum parallelism for processing the orthogonal range queries. Moreover, there is no duplication of records and no increase in insertion/deletion cost.
Report on German Joint Venture Tool Integration Projects
Authors: G. Merbeth
Venue: Proceedings of the 1987 Fall Joint Computer Conference on Exploring technology: today and tomorrow (1987)

A wide range of high standard software engineering tools is available worldwide. For most users, however, the possibility of integrating various tools to a software production environment is insufficient. In an attempt to improve this situation and to make use of existing tools, major German tool suppliers and research institutes started in 1985, with the support of the German Federal Ministry for Research and Technology (BMFT), joint projects in which a high degree of inter- connectability between their tools should be achieved. This is a report of these four projects, their results and experiences.
An Approach to User Specification of Interactive Display Interfaces
Authors: Leonard J. Bass
Venue: IEEE Transactions on Software Engineering (1985)

Forms have become widely used as a user interface for database systems. By analyzing the components of forms, a unified treatment of aggregation operators, headings, subheadings, and internal logic of a form is possible. In this paper we present a theory and a system based on that theory which allows users to easily specify displays. Displays are composed of components and the user can specify geometry of the components and grouping relationships between the components which allow for the generation of the desired display.
Self-assessment procedure XVII
Authors: Eric A. Weiss
Venue: Communications of the ACM (1987)

A self-assessment procedure dealing with ACM
Floating-Point to Logarithmic Encoder Error Analysis
Authors: Thanos Stouraitis, Fred J. Taylor
Venue: IEEE Transactions on Computers (1988)

The logarithmic number (LNS), which supports high-speed, high-precision arithmetic, is envisioned as a possible arithmetic coprocessor attachment to a floating-point (FLP) processor. An error analysis of an FLP-to-LNS encoder is presented. Analytic expressions for the probability density function of the encoding error are derived for a number of cases, according to the memory word lengths used for the encoding. Simulation has verified the theoretical results.
Some comments on &ldquo;Pitfalls in Prolog Programming&rdquo;
Authors: W F Clocksin
Venue: ACM SIGPLAN Notices (1986)

In their useful article "Pitfalls in Prolog Programming", Ng and Ma [1] discuss some ways that novice programmers can be confused while learning Prolog. They suggest that the confusions result from certain properties of Prolog, in particular the way that it diverges from the "ideal" of programming in pure logic. In fact, I suggest that Ng and Ma are attributing to Prolog powers that it simply does not have, and that confusions are usually the result of the novice's misplaced confidence in his abilities to reason about programs.
Self-improvement in problem-solving
Authors: R B Banerji
Venue: Proceedings of the ACM SIGART international symposium on Methodologies for intelligent systems (1986)

For the purposes of this paper self-improvement will be defined to be the automatic development of problem solving heuristics. The reason for such a narrow definition will be indicated. Precise formulation of the concepts of problem and game will form the basis for the discussion of self-improving programs and an attempt to deal with the question of their adequacies. The relationship between self improvement and the process of learning will be established in specific cases. The idea of &ldquo;proof generalization&rdquo; as a basis of self-improvement will also be discussed. Case studies, where they exist and are understood will be indicated.
DELIS: A decision support system generator for frequency data
Authors: Richard W. Butterworth, Robert A. Stephan
Venue: ACM SIGAPL APL Quote Quad (1986)

The title of this paper suggests two concepts, namely Decision Support Systems (DSS) and frequency style data, that were built upon by the APL application called &ldquo;DELIS&rdquo;. DELIS was developed originally for interactive display of certain frequency data arrays, and has evolved over the past 8 years into a comprehensive system for developing a broad class of related applications. Our paper's objective is to explain the title concepts well enough to give the reader a feel for the DELIS design and to explain generally how APL was used in its implementation. The concepts work well together in a way that seems natural to APL users and that may have applicability for other designers and developers of APL based information systems.
Some problems arising out of the cross-disciplinary nature of information systems security
Authors: Tung-chien Wang
Venue: ACM SIGCPR Computer Personnel (1987)

Information Systems Security has recently become an important issue. As this subject crosses three main academic fields and professions -- risk management, auditing and information systems -- three main kinds of problems arise: organization management problems, education problems, and research and development problems. This paper will propose the following:1. A new point in management theory -- that risk management departments are the appropriate location for the "information security risk manager" (ISRM) position with its professional standards.2. A new interdisciplinary course for managing information systems security.3. The establishment of data and knowledge bases for information security risk management to develop expert systems in a way that would fully incorporate currently diverse efforts to modify or correct past directions and to point out future directions.
The object management system of PCTE as a software engineering database management system
Authors: Ferdinando Gallo, Regis Minot, Ian Thomas
Venue: Proceedings of the second ACM SIGSOFT/SIGPLAN software engineering symposium on Practical software development environments (1987)

The PCTE project is specifying, designing and implementing a host structure for Software Engineering Environments. The host structure is designed to run on powerful, bitmap screen terminals connected to a local network. It features an Object Management System based on a Binary Entity-Relationship model that manages a database that is transparently distributed over the workstations connected to the network. Migration to this new hosting structure is facilitated by compatibility at the executable file level with Unix System V*. This paper examines how the OMS corresponds to the requirements for Software Engineering databases.