ppxscal/embedding_network huggingface dataset:
A specification language to assist in analysis of discrete event simulation models
Authors: C Michael Overstreet, Richard E. Nance
Venue: Communications of the ACM (1985)

Effective development environments for discrete event simulation models should reduce development costs and improve model performance. A model specification language used in a model development environment is defined. This approach is intended to reduce modeling costs by interposing an intermediate form between a conceptual model (the model as it exists in the mind of the modeler) and an executable representation of that model. As a model specification is constructed, the incomplete specification can be analyzed to detect some types of errors and to provide some types of model documentation. The primitives used in this specification language, called a condition specification (CS), are carefully defined. A specification for the classical patrolling repairman model is used to illustrate this language. Some possible diagnostics and some untestable model specification properties, based on such a representation, are summarized.
Adaptive forward differencing for rendering curves and surfaces
Authors: Sheue-Ling Lien, Michael Shantz, Vaughan Pratt
Venue: Proceedings of the 14th annual conference on Computer graphics and interactive techniques (1987)

An adaptive forward differencing algorithm is presented for rapid rendering of cubic curves and bicubic surfaces. This method adjusts the forward difference step size so that approximately one pixel is generated along an ordinary or rational cubic curve for each forward difference step. The adjustment involves a simple linear transformation on the coefficients of the curve which can be accomplished with shifts and adds. This technique combines the advantages of traditional forward differencing and adaptive subdivision. A hardware implementation approach is described including the adaptive control of a forward difference engine. Surfaces are rendered by drawing many curves spaced closely enough together so that no pixels are left unpainted. A simple curve anti-aliasing algorithm is also presented in this paper. Anti-aliasing cubic curves is supported via tangent vector output at each forward difference step. The adaptive forward differencing algorithm is also suitable for software implementation.
Active objects in hybrid
Authors: O. M. Nierstrasz
Venue: Conference proceedings on Object-oriented programming systems, languages and applications (1987)

Most object-oriented languages are strong on reusability or on strong-typing, but weak on concurrency. In response to this gap, we are developing Hybrid, an object-oriented language in which objects are the active entities. Objects in Hybrid are organized into domains, and concurrent executions into activities. All object communications are based on remote procedure-calls. Unstructured sends and accepts are forbidden. To this the mechanisms of delegation and delay queues are added to enable switching and triggering of activities. Concurrent subactivities and atomic actions provided for compactness and simplicity. We show how solutions to many important concurrent problems, such a pipelining, constraint management and &ldquo;administration&rdquo; can be compactly expressed using these mechanisms.
Modeling Multicomputer Systems with PARET
Authors: Kathleen Nichols, John T. Edmark
Venue: Computer (1988)

The authors discuss the parallel architecture and evaluation tool (PARET), a software package that provides a multicomputer system laboratory for studying the interaction of algorithms and architectures; the effects of varying physical resources on system performance; and alternate mapping, scheduling, and routing strategies, both static and dynamic. To handle the complexity of the problem and explore performance questions, PARET provides an interactive and animated environment in which the user exercises multicomputer models. The authors examined previous and related work, examine PARET's unified modeling approach and its user interface. They present two PARET models to illustrate the modeling process.
A generalized model management system for mathematical programming
Authors: Daniel R. Dolk
Venue: ACM Transactions on Mathematical Software (TOMS) (1986)

This paper examines mathematical programming software in the context of model management and decision support. The concept of a model management system (MMS) is introduced and compared to traditional modeling systems. An MMS is seen as a much more generalized software system that requires the confluence of existing operations research, database management, and artificial intelligence techniques. By incorporating powerful, abstraction-based representation structures, an MMS can support multiple levels of model abstraction, only one of which corresponds to traditional, solution-oriented modeling software. The database structures required to implement a knowledge-based MMS are discussed and a prototype system for mathematical programming, the Generalized eXperimental Math Programming system (GXMP), is described. An algebraic language developed for use in GXMP is described in detail.
Operator work load: when is enough enough?
Authors: Moira LeMay, Eric Hird
Venue: Communications of the ACM (1986)

Three measures of operator mental work load were tested with a large, interactive computer system. Two&mdash;operator rating of time stress, and the ratio of the time required to time allowed for each subtask&mdash;proved to be significant and easy to use.
Engineering VAX Ada for a multi-language programming environment
Authors: Charles Z Mitchell
Venue: Proceedings of the second ACM SIGSOFT/SIGPLAN software engineering symposium on Practical software development environments (1987)

DIGITAL's VAX&trade; Adar is a validated, production-quality implementation of the full Ada language that is well-integrated into the VMS&trade; operating system environment on VAX systems. The programming support environment consists of an Ada compiler, an Ada program library manager, and a multi-language programming environment including a variety of tools which all work together. The Ada compiler has many features which allow full access to the underlying operating system and hardware and which permit the use of Ada in mixed language programs in the VAX/VMS Common Language Environment. The Ada program library manager provides Ada-specific features to reduce manual bookkeeping by programmers and to support programming projects. Some of the available multi-language tools include a source code tracking system, a language-sensitive editor, a symbolic debugger, a performance and test coverage analyzer, and a test system manager.
Controls for Interorganization Networks
Authors: Deborah Estrin
Venue: IEEE Transactions on Software Engineering (1987)

Interorganization computer networks support person-to-person communication via electronic mail; exchange of cad/cam data, software modules, or documents via file transfer; input to an order-entry or accounting system via a database query and update protocol; and use of shared computational resources via an asynchronous message protocol or remote login. In most such interorganization arrangements, the set of resources that an organization wants to make accessible to outsiders is significantly smaller than the set of resources that it wants to remain strictly-internal (i.e., accessible to employees of the organization only). In addition, because the potential user is a person (or machine) outside the boundaries of the organization, the damage associated with undesired use can be high. Because of these characteristics, Interorganization Networks (ION's) have unique usage-control requirements.
Approach to a disciplined development process - the ISTAR integrated project support environment
Authors: M Lehman
Venue: ACM SIGSOFT Software Engineering Notes (1986)

This paper is an extended, written, version of a presentation to the Second Process Workshop. It presents a systematic, top down, approach to the design of integrated project and programming support environments (IPSEs) using the ISTAR project at Imperial Software Technology Ltd as an illustration. In the context of the Workshop the talk was intended to describe an approach to software development and evolution in general. If that be his concern the reader may so interpret the text. Alternatively it may be seen as an introduction to ISTAR and a contribution to IPSE development technology.
The tea-leaf reader algorithm: an efficient implementation of CRC-16 and CRC-32
Authors: Georgia Griffiths, G. Carlyle Stones
Venue: Communications of the ACM (1987)

The tea-leaf reader CRC algorithms are error-detection algorithms that use a look-ahead table to increase execution speed.
APL as a prototyping language: case study of a compiler development project
Authors: Matsuki Yoshino
Venue: ACM SIGAPL APL Quote Quad (1986)

We are applying prototyping method using APL to a commercial compiler's development Project. This paper will discuss the following matters based on our one year experience of the project: Merits of APL as a prototyping language. An environment of the prototype. A representation of tables and the intermediate language of compilers in an APL environment. A strategy of transforming the APL prototype into final product written in Pascal. Evaluation of this method.
Knowledge-based support for system verification during requirements analysis
Authors: Mohan R Tanniru, S Sakthivel
Venue: Proceedings of the conference on The 1987 ACM SIGBDP-SIGCPR Conference (1987)

Requirement analysis is the first step in the development of information systems and its objective is to ensure that any proposed system meets the projected requirements of the user. As a part of this requirement analysis, an analyst is asked to verify that the proposed system is representationally accurate before undertaking any other evaluation. This paper proposes a Petri Net representation of an information system and the use of a PROLOG-based knowledge base to test its representational accuracy.
Measuring Consensus Effectiveness by a Generalized Entropy Criterion
Authors: Harry E. Stephanou
Venue: IEEE Transactions on Pattern Analysis and Machine Intelligence (1988)

A quantitative criterion for measuring the effectiveness of the consensus obtained by pooling evidence from two knowledge sources is introduced. A brief review of the Dempster-Shafer theory of mathematical evidence, which is based on a set-theoretic description of subjective uncertainty, is given. The concept of generalized entropy as a measure of the uncertainty in a knowledge source is also introduced. It is proven that the pooling of evidence by Dempster's rule of combination decreases the total amount of generalized entropy in the knowledge sources. The decrease of entropy corresponds to the focusing of knowledge, and is used as a measure of consensus effectiveness. Several examples are used to illustrate this measure.
Panel: Extensible database systems
Authors: D. S. Batory, M. Mannino
Venue: ACM SIGMOD Record (1986)

New implementation techniques and new capabilities for database systems are being developed and proposed at a rapid rate. Novel file structures and improved algorithms for query optimization, buffer and recovery management, and transaction management have the potential of realizing significant gains in DBMS performance. The proposed integration of design objects, voice, text, rules, vector graphics, and images into databases promises exciting new capabilities for DBMSs. To accommodate advances in database technology and to support new classes of database applications, DBMSs must be extensible (i.e., customizable). To achieve extensibility forces a fundamental rethinking about how DBMSs are built, and how special-purpose features can be integrated into a DBMS with little effort and expense. Customizing DBMSs implies the availability of extensible data models, to allow for the introduction of new object types and operations, and extensible storage structures, to take advantage of special properties of stored data or operations to enhance performance. Although research on extensible DBMSs is still in its infancy, a fundamental concept underlying their construction is now evident. This is the standardization of interfaces and the plug-compatibility of modules. An extensible DBMS will be a 'software bus' whereby new modules (and hence new DBMS capabilities) can be added, exchanged, or removed by plugging or unplugging modules. Extensible DBMSs will thus rely on extensive software libraries, where new modules can be added as needed. Furthermore, changes to DBMSs can be made in months rather than years, and the reinvention of established technology is kept to a minimum because of the reusability of modules. The perception of DBMSs as monolithic entities that are difficult to modify will change as extensible DBMS technology becomes better understood. The use of database systems will not change, the ANSI/SPARC roles of database users, who write and execute transactions, and the database administrator (DBA), who designs and writes database schemas, will remain. Extensible DBMSs will require the introduction of an additional party, the database architecture administrator (DDA), who is responsible for the construction and customization of a DBMS. A growing number of researchers are developing extensible DBMSs. The purpose of this panel is to explain and discuss some of the approaches that are now being taken (and those that can be taken), and to survey the problems that confront extensible database technology. Descriptions of the systems and research represented at this panel are given in the following sections.
Parsing and compiling using Prolog
Authors: Jacques Cohen, Timothy J. Hickey
Venue: ACM Transactions on Programming Languages and Systems (TOPLAS) (1987)

This paper presents the material needed for exposing the reader to the advantages of using Prolog as a language for describing succinctly most of the algorithms needed in prototyping and implementing compilers or producing tools that facilitate this task. The available published material on the subject describes one particular approach in implementing compilers using Prolog. It consists of coupling actions to recursive descent parsers to produce syntax-trees which are subsequently utilized in guiding the generation of assembly language code. Although this remains a worthwhile approach, there is a host of possibilities for Prolog usage in compiler construction. The primary aim of this paper is to demonstrate the use of Prolog in parsing and compiling. A second, but equally important, goal of this paper is to show that Prolog is a labor-saving tool in prototyping and implementing many non-numerical algorithms which arise in compiling, and whose description using Prolog is not available in the literature. The paper discusses the use of unification and nondeterminism in compiler writing as well as means to bypass these (costly) features when they are deemed unnecessary. Topics covered include bottom-up and top-down parsers, syntax-directed translation, grammar properties, parser generation, code generation, and optimizations. Newly proposed features that are useful in compiler construction are also discussed. A knowledge of Prolog is assumed.
A relational model for unstructured documents
Authors: A. Salminen
Venue: Proceedings of the 10th annual international ACM SIGIR conference on Research and development in information retrieval (1987)

The logical structure of a document is usually a tree in which the order of the nodes is important at least at some level of the tree. We call a document unstructured if its structure is a single-level ordered tree. The purpose of this paper is to present a many-sorted algebra for handling unstructured documents. The documents in the model are represented by relations. An algebra for handling documents of one type can be extended to an algebra for handling documents of several types. Further, an algebra for handling documents can be extended by the relational algebra for handling documents and relations in a common algebra. The model of this paper can be regarded as a part of a general document model. On the other hand, unstructured documents themselves are an important group of documents. We will show by examples that the simple model covers a wide range of document handling and information retrieval problems.
Saving time and space in spline calculations
Authors: George C Bush
Venue: ACM SIGNUM Newsletter (1987)

There are many descriptions in the literature of the use of cubic splines for interpolation, approximating derivatives, etc. The purpose of this note is to explore some shortcuts in computation that are possible if the tabular points (knots) are equally spaced.
Environmental Testing Techniques for Software Certification
Authors: Myron S. Karasik
Venue: IEEE Transactions on Software Engineering (1985)

The problems of developing software requirements and quality assurance techniques have basically dealt with an environment where a single organization acts as the designer, developer, and user of the software product. Since the mid-1970' s, however, there has been a great increase in the use of "packaged" software products designed and developed by one organization for use in a variety of other organizations. The great profusion of products has resulted in many products being peddled for generic applications (accounting, manufacturing, etc.) which are of questionable quality and/or "fit" to a given organization's environment. This paper describes some techniques that are being used to certify software produced by third parties and how to determine if the "fit" is there. Current quality assurance techniques deal with the "correctness" of a program as compared to its specifications [2], [4], [7], [8], [12]. The real issue for a purchaser of software is whether the software is "correct" for its environment.
Extending a database system with procedures
Authors: Michael Stonebraker, Jeff Anton, Eric Hanson
Venue: ACM Transactions on Database Systems (TODS) (1987)

This paper suggests that more powerful database systems (DBMS) can be built by supporting database procedures as full-fledged database objects. In particular, allowing fields of a database to be a collection of queries in the query language of the system is shown to allow the natural expression of complex data relationships. Moreover, many of the features present in object-oriented systems and semantic data models can be supported by this facility. In order to implement this construct, extensions to a typical relational query language must be made, and considerable work on the execution engine of the underlying DBMS must be accomplished. This paper reports on the extensions for one particular query language and data manager and then gives performance figures for a prototype implementation. Even though the performance of the prototype is competitive with that of a conventional system, suggestions for improvement are presented.
A project-based course in compiler construction
Authors: Harbans L. Sathi
Venue: Proceedings of the seventeenth SIGCSE technical symposium on Computer science education (1986)

The paper describes the experience gained by teaching a project-based course in Compiler Construction. The course is a blend of theoretical concepts and practical considerations that go into the development of a compiler. A project in compiler writing is an important component of this course. ASP, a subset of standard PASCAL, is used as the source language. The compiler for ASP is to be developed in various phases: character manipulator, lexical analyzer, syntax analyzer, semantic analyzer, and code generator. Recursive descent method is used to parse the various syntactic entities. The code generator emits code for a hypothetical machine called AOC (ALGOL Object Code). A simulator executes this code.
A crisis in computer science education at liberal arts colleges
Authors: Greg W Scrugg
Venue: ACM SIGCSE Bulletin (1987)

A crisis now pervades computer science education at small liberal arts colleges: too many programs are not able to boot strap their programs into existence at a level where they can sustain themselves. The costs, not necessarily in dollars, have far exceeded the original expectations of the colleges, resulting in inappropriate environments, inadequate educational goals, broken faculty careers and unrealistic research expectations, and ultimately failure of the programs as bonafide computer science. In what follows, I take as a given that computer science is not only an appropriate, but a central and important discipline for liberal arts colleges. This has been argued elsewhere and will not be addressed here, as my primary concern is with the institutions which have (at least officially) accepted this premise.I will first attempt to describe the major symptoms and then the causes of some of the problems encountered by many small liberal arts colleges. Finally, I will offer a preliminary set of suggestions for possible solution.
A simple parallel algorithm for the maximal independent set problem
Authors: M Luby
Venue: Proceedings of the seventeenth annual ACM symposium on Theory of computing (1985)

Simple parallel algorithms for the maximal independent set (MIS) problem are presented. The first algorithm is a Monte Carlo algorithm with a very local property. The local property of this algorithm may make it a useful protocol design tool in distributed computing environments and artificial intelligence. One of the main contributions of this paper is the development of powerful and general techniques for converting Monte Carlo algorithms into deterministic algorithms. These techniques are used to convert the Monte Carlo algorithm for the MIS problem into a simple deterministic algorithm with the same parallel running time.
Use of mathematical switches to solve differential equation problems
Authors: Yi Ling Chiang
Venue: ACM SIGNUM Newsletter (1986)

Mathematical switches have been used to choose the suitable numerical scheme automatically at every computing step while solving differential equation problems with a multischeme approach. The concept of using mathematical switches in a numerical computation with a multiprocessor computer is feasible. The use of the switches in a multischeme computation yields a more accurate solution than the use of only a single scheme. We examined the use of two mathematical switches, namely, the one of exact error and of truncation error. The numerical results from the use of the former switch confirmed our conjecture that a combined solution of several schemes is indeed more accurate than one of an individual scheme. However, a switch of exact error is not practical and the one of truncation error is not satisfactory. Hence, further study is needed to design more practical and more satisfactory mathematical switches, and to establish the practical value on their use.
A comment on &ldquo;A note on Einstein metrics&rdquo;
Authors: Eberhard Schrüfer
Venue: ACM SIGSAM Bulletin (1988)

In a recent note, Nielsen and Pedersen [1] reported how they verified some solutions of Einstein's field equations with the help of REDUCE. They used a program which is contained in the standard REDUCE [2] testfile and which was written by Barton and Fitch.
A new analysis of LALR formalisms
Authors: Joseph C.H. Park, K. M. Choe, C. H. Chang
Venue: ACM Transactions on Programming Languages and Systems (TOPLAS) (1985)

The traditional LALR analysis is reexamined using a new operator and an associated graph. An improved method that allows factoring out a crucial part of the computation for defining states of LR(0) canonical collection and for computing LALR(1) lookahead sets is presented. This factorization leads to significantly improved algorithms with respect to execution time as well as storage requirements. Experimental results including comparison with other known methods are presented.