ppxscal/embedding_network huggingface dataset:
An introductory algorithm teacher
Authors: William G. Bulgren, Rose M. Marra, Gregory F. Wetzel
Venue: Proceedings of the eighteenth SIGCSE technical symposium on Computer science education (1987)

A non-machine specific design of an algorithm teacher is proposed. It is a programmed environment to help students in a beginning computer science course learn problem solving skills. This paper provides an overview of the problem, a motivation and justification, followed by a brief description of what the program should provide the student.
Impulse-86: a substrate for object-oriented interface design
Authors: Reid G. Smith, Rich Dinitz, Paul Barth
Venue: ACM SIGPLAN Notices (1986)

Impulse-86 provides a general and extensible substrate upon which to construct a wide variety of interactive user interfaces for developing, maintaining, and using knowledge-based systems. The system is based on five major building blocks: Editor, Editor Window, PropertyDisplay, Menu, and Operations. These building blocks are interconnected via a uniform framework and each has a well-defined set of responsibilities in an interface.Customized interfaces can be designed by declaratively replacing some of the building blocks in existing Impulse-86 templates. Customization may involve a wide range of activities, ranging from simple override of default values or methods that control primitive operations (e.g., font selection), to override of more central Impulse-86 methods (e.g., template instantiation). Most customized interfaces require some code to be written&mdash;to handle domain-specific commands. However, in all cases, the Impulse-86 substrate provides considerable leverage by taking care of the low-level details of screen, mouse, and keyboard manipulation.Impulse-86 is implemented in Strobe, a language that provides object-oriented programming support for Lisp. This simplifies customization and extension.
A minicomputer network management monitoring and analysis system using APL
Authors: Fred A. Gross,  III, James C. Taylor
Venue: ACM SIGAPL APL Quote Quad (1987)

This article describes an integrated group of utilities distributed about an eleven super-minicomputer network for such purposes as mediating network-wide file backup without user intervention, centralized verification of all archival processes, centralized monitoring and analysis of network and individual node statistics, general system housekeeping, and notification of systems staff of trouble spots (particularly security and system use growth behavior). This facility uses APL (the Data General APL Interpreter AOS/VS APL&trade;) for network control and file transfer, use of remote network node peripherals, interpretation of native files and file structures, native system logging processes, and for the creation and manipulation of APL and non-APL processes.
An event/trigger mechanism to enforce complex consistency constraints in design databases
Authors: Klaus R. Dittrich, Angelika M. Kotz, Jutta A. Mülle
Venue: ACM SIGMOD Record (1986)

Data objects in engineering applications, especially computer aided design, show highly complex structures and a lot of intricate dependencies. Hence a large amount of variably composed consistency constraints have to be dealt with. Furthermore, long transactions which are typical for CAD result in the need to tolerate inconsistencies over unpredictably long periods of time. The demands on mechanisms to enforce consistency in design database systems thus differ from those in business and administrative applications. Comprehensive consistency of the design data can only be attained by degrees. The time and extent of checking have to be determined dynamically and under control by the user. In the case of consistency violations, flexible kinds of reaction are necessary. In this paper we propose an event/trigger mechanism to enforce consistency in design databases that complements the transaction-oriented mechanisms suitable for traditional applications. The underlying ideas are derived from exception handling in programming languages. We present in detail the requirements to meet and how our concept copes with them. We also present an implementation that provides reasonable performance.
Discrete-event simulation in Ada: concepts
Authors: R. W. Shore
Venue: ACM SIGAda Ada Letters (1987)

Ada was designed to include unique features which make it appropriate for a wide variety of programming tasks. In addition, the packaging and separate-compilation features of Ada allow a programmer to extend the language through the inclusion of specialized toolkits for specific applications. This paper discusses the concepts behind a series of Ada packages which allow a programmer to construct a discrete-event simulation in Ada. A simple barbership simulation is used as a running example.
How to share memory in a distributed system
Authors: Eli Upfal, Avi Wigderson
Venue: Journal of the ACM (JACM) (1987)

The power of shared-memory in models of parallel computation is studied, and a novel distributed data structure that eliminates the need for shared memory without significantly increasing the run time of the parallel computation is described. More specifically, it is shown how a complete network of processors can deterministically simulate one PRAM step in O(log n/(log log n)2) time when both models use n processors and the size of the PRAM's shared memory is polynomial in n. (The best previously known upper bound was the trivial O(n)). It is established that this upper bound is nearly optimal, and it is proved that an on-line simulation of T PRAM steps by a complete network of processors requires &OHgr;(T(log n/ log log n)) time. A simple consequence of the upper bound is that an Ultracomputer (the currently feasible general-purpose parallel machine) can simulate one step of a PRAM (the most convenient parallel model to program) in O((log n)2log log n) steps.
Tree-Based Broadcasting in Multihop Radio Networks
Authors: I. Chlamtac, S. Kutten
Venue: IEEE Transactions on Computers (1987)

This paper considers the issue of broadcasting protocols in multihop radio networks. The objective of a broadcasting protocol is to deliver the broadcasted message to all network nodes. To efficiently achieve this objective the broad- casting protocol in this paper utilizes two basic properties of the multihop radio network. One is the broadcast nature of the radio which allows every single trasmission to reach all nodes that are in line of sight and within range of the transmitting node. The other, spatial reuse of the radio channel, which due to the multihop nature of the network allows multiple simultaneous transmissions to be received correctly. The proposed protocol incorporates these properties to obtain a collision free forwarding of the broadcasted message on a tree. Centralized and distributed algorithms for the tree construction are presented. The obtained trees are unique in incorporating radio oriented time ordering as part of their definition. In this way multiple copies of one or more broadcasted messages can be transmitted simultaneously without collision, requiring only a small number of message transmissions. Consequently, the protocol not only guarantees that the broadcasted message reaches all network nodes in bounded time, but also ensures that the broadcasting activity will use only limited channel bandwidth and node memory. The proposed broadcast protocol thus possesses the advantages of TDM solutions while allowing the channel bandwidth to be shared, concurrently with the broadcast, with other transmission activities as dictated, for instance, by data link protocols. Some NP-completeness proofs are also given.
Case study: IBM's system/360-370 architecture
Authors: David Gifford, Alfred Spector
Venue: Communications of the ACM (1987)

The architecture of IBM's System/360-370 series of compatible processors is one of the most durable artifacts of the computer age. Through two major revisions of the product line and 23 years of technological change, it has remained a viable and versatile interface between machine and user.
A new compaction scheme based on compression ridges
Authors: P. C. Shah, H. N. Mahabala
Venue: Proceedings of the 24th ACM/IEEE Design Automation Conference (1987)

This paper presents a compaction scheme, based on the concept of compression ridges (CRs). The virtual grid based stick diagram of a layout is first converted automatically into a detailed layout which confirms to the design rules. All CRs are enumerated in both X and Y directions and their widths are calculated. The technique for choosing the CR to use for squeezing is based on the fact that a CR not only reduced area based on its width and length but may also preempt the reduction by some other CRs, both in the same and orthogonal directions. Choosing a CR with a certain width may reduce the maximum reduction possible (calculated based on a flow model) in the same direction and in the orthogonal direction (due to X-Y decision). Each CR is associated with a weight which signifies a measure of net reduction in area possible and the one with maximum weight is chosen to compact at each step.
Use of graph-theoretic models for optimal relational database accesses to perform join
Authors: Sakti Pramanik, David Ittner
Venue: ACM Transactions on Database Systems (TODS) (1985)

A graph model is presented to analyze the performance of a relational join. The amount of page reaccesses, the page access sequence, and the amount of buffer needed are represented in terms of graph parameters. By using the graph model formed from the index on the join attributes, we determine the relationships between these parameters. Two types of buffer allocation strategies are studied, and the upper bound on the buffer size with no page reaccess is given. This bound is shown to be the maximum cut value of a graph. Hence, the problem of computing this upper bound is NP-hard. We also give algorithms to determine a page access sequence requiring a near optimal buffer size with no page reaccess. The optimal page access sequence for a fixed buffer size has also been considered.
A system development model for a changing environment
Authors: Bernard C Glasson
Venue: Proceedings of the twenty-first annual conference on Computer personnel research (1985)

The traditional approaches to system development are being challenged by the improved end-user software that is becoming available for traditional users and systems professionals in their roles as system developers. To meet these challenges there might need to be a fundamental rethink of the traditional approaches at a step back from the ongoing methodological debate that is presently evidencing the profession's response to these challenges. This paper proposes one solution which is the result of an in depth study of methodologies. It proposes an approach that utilises a comprehensive but highly adaptable system development model &mdash; which is based on human activities, development roles, a comprehensive set of potential development tasks and a means of establishing and supporting the relationship between all three by software. It is claimed that the approach can be effectively applied in order to respond positively to the changing system development environment.
Stepwise Refinement and Verification in Box-Structured Systems
Authors: Harlan D. Mills
Venue: Computer (1988)

The author proposes that the formality of specifications and designs be developed together in box structures with many sponsor and user interfaces. Box structures of data abstractions allow the stepwise refinement and verification of hierarchical system designs from their specifications at formal and informal levels. He discusses the features and advantages of the approach. He used a navigation and weather buoy case study and gives a detailed, step-by-step application of the method.
Description of an extension of the Matrix package of :20Reduce&rdquo;
Authors: H Caprasse
Venue: ACM SIGSAM Bulletin (1986)

Matrix manipulations in REDUCE [1] are governed by a matrix subprogram made by HEARN which works nicely but gives too restrictive possibilities to the user working exclusively in the algebraic mode. Specifically, apart from the basic algebraic operations, one has the possibilities to compute the inverse, the transpose, the determinant and the trace of a matrix.
A logical design methodology for relational databases using the extended entity-relationship model
Authors: Toby J. Teorey, Dongqing Yang, James P. Fry
Venue: ACM Computing Surveys (CSUR) (1986)

A database design methodology is defined for the design of large relational databases. First, the data requirements are conceptualized using an extended entity-relationship model, with the extensions being additional semantics such as ternary relationships, optional relationships, and the generalization abstraction. The extended entity-relationship model is then decomposed according to a set of basic entity-relationship constructs, and these are transformed into candidate relations. A set of basic transformations has been developed for the three types of relations: entity relations, extended entity relations, and relationship relations. Candidate relations are further analyzed and modified to attain the highest degree of normalization desired. The methodology produces database designs that are not only accurate representations of reality, but flexible enough to accommodate future processing requirements. It also reduces the number of data dependencies that must be analyzed, using the extended ER model conceptualization, and maintains data integrity through normalization. This approach can be implemented manually or in a simple software package as long as a "good" solution is acceptable and absolute optimality is not required.
The elicitation of system knowledge by picture probes
Authors: P. Barnard, M. Wilson, A. MacLean
Venue: ACM SIGCHI Bulletin (1986)

A technique is described in which a user's knowledge of a software package is elicited by means of a series of photographs depicting the system in a variety of states. The resultant verbal protocols were codified and scored in relation to the way in which the system actually worked. In the illustrative study described, the probes were administered twice after 5 and 10 hrs of system experience with an office product (VisiOn*). The number of true claims elicited increased with experience but the number of false claims remained stable. The potential value of the technique and its output are discussed.
Extending the relational algebra to support transaction time
Authors: Edwin McKenzie, Richard Snodgrass
Venue: ACM SIGMOD Record (1987)

In this paper we discuss extensions to the conventional relational algebra to support transaction time. We show that these extensions are applicable to historical algebras that support valid time, yielding a temporal algebraic language. Since transaction time concerns the storage of information in the database, the notion of state is central. The extensions are formalized using denotational semantics. The additions preserve the useful properties of the conventional relational algebra.
A turnable protocol for symmetric surveillance in distributed systems
Authors: B Walter
Venue: Proceedings of the ACM SIGCOMM conference on Communications architectures protocols (1986)

In distributed systems surveillance protocols are used for monitoring the status of remote sites. A remote site is regarded as being available as long as messages are received from this site, otherwise it is regarded as being unavailable. If a site becomes unavailable, this will be reported to other sites and recovery actions can be initiated. Using an example it will be shown that in certain cases it is necessary, that whenever some site S1 detects the unavailability of some other site S2, within a fixed amount of time S2 must also have detected an unavailability of S1. Unfortunately, this cannot be guaranteed by existing surveillance protocols. Another problem with existing protocols is, that remote sites are usually reported as being unavailable after being timed out only once, i.e. the loss of just one message might cause complete systems to back out. Two versions of a protocol for so-called symmetric surveillance are presented. Both guarantee, that if S1 detects the unavailability of S2 at time t0, then S2 (provided that S2 has not crashed) will become aware of this fact at t1 such that [t1 - t0] < &Dgr;. This property is of special interest for handling network partitionings. Additionally, one of the versions is tunable, i.e. it can be specified, how many timeouts may occur before a site is regarded as being unavailable.
SEGRAS—a formal and semigraphical language combining Petri nets and abstract data types for the specification of distributed systems
Authors: B. Krämer
Venue: Proceedings of the 9th international conference on Software Engineering (1987)

SEGRAS is formal language for writing and analyzing specifications of distributed software systems. It unifies algebraic specifications of abstract data types with high-level Petri net specifications of nonsequential systems in a common syntactic and semantic framework. The data structure of a system, the information content of its local states, and static constraints to state changes are specified algebraically using positive conditional equations. Dynamic behavior is specified by high level Petri nets. Each net defines a (distributed) initial state and a partial ordering in which state changing operations may happen. SEGRAS addresses advanced programming methodologies by offering facilities for modularization and parameterization, and a type system which supports polymorphism with dependent types, higher-order types, subtypes, and overloading. Some examples are given to illustrate these language concepts.
Applications of Byzantine agreement in database systems
Authors: Hector Garcia Molina, Frank Pittelli, Susan Davidson
Venue: ACM Transactions on Database Systems (TODS) (1986)

In this paper we study when and how B Byzantine agreement protocol can he used in general-purpose database management systems. We present an overview of the failure model used for Byzantine agreement, and of the protocol itself. We then present correctness criteria for database processing in this failure environment and discuss strategies for satisfying them. In doing this, we present new failure models for input/output nodes and study ways to distribute input transactions to processing nodes under these models. Finally, we investigate applications of Byzantine agreement protocols in the more common failure environment where processors are assumed to halt after a failure.
Provably good routing in graphs: regular arrays
Authors: P Raghavan, C D Thompson
Venue: Proceedings of the seventeenth annual ACM symposium on Theory of computing (1985)

We examine the problem of routing wires on a VLSI chip where the nodes to be connected are arranged in a two-dimensional array. We develop provably good algorithms that find a solution close to the optimal one with high probability. Our approximation algorithms solve the relevant 0-1 integer optimization problems by solving their relaxed versions and then rounding by an interesting probabilistic technique. One of our algorithms, using multicommodity flow, has applications to routing in circuit switching networks.
Strategies for encouraging successful adoption of office communication systems
Authors: Susan F. Ehrlich
Venue: ACM Transactions on Information Systems (TOIS) (1987)

The adoption of new computer communication systems into organizations requires behavioral change. Planning for successful adoption requires knowledge of individual organizational communication patterns and the relationship between those patterns and particular communication system solutions. This paper documents a sequence of studies of organizational communication. Needs for office communication systems were identified, as were social and psychological factors temporarily inhibiting their use. Strategies for assuring smooth adoption of such systems are highlighted.
Portability of syntax and semantics in DATALOG
Authors: Carole D. Hafner, Kurt Godden
Venue: ACM Transactions on Information Systems (TOIS) (1985)

This paper presents a discussion of the techniques developed and problems encountered during the design, implementation, and experimental use of a portable natural language processor. Datalog (for &ldquo;database dialogue") is an experimental natural language query system, which was designed to achieve a maximum degree of portability and extendibility. Datalog uses a three-level architecture to provide both portability of syntax to new and extended tasks and portability of semantics to new database applications. The implementation of each of the three levels, the structures and conventions that control the interactions among them, and the way in which different aspects of the design contribute to portability are described. Finally, two specific, implemented examples are presented, showing how it was possible to transport or extend Datalog by changing only one &ldquo;layer&rdquo; of the system's knowledge and achieve correct processing of the extended input by the entire system.
On the Design of Pseudoexhaustive Testable PLAs
Authors: D. S. Ha, S. M. Reddy
Venue: IEEE Transactions on Computers (1988)

A method is presented to design pseudoexhaustive testable (PET) PLAs (programmable logic arrays) that are suitable for BIST (built-in self-test) environments. The key idea of the design is to partition inputs and product lines into groups. During testing, a group of inputs and a group of product lines are selected and tested exhaustively. The proposed design leads to small test sizes and relatively small area overhead. Experimental results on 30 PLAs, comparing test set sizes and area overhead of different BIST PLA designs, are reported.
Automating the design of graphical presentations of relational information
Authors: Jock Mackinlay
Venue: ACM Transactions on Graphics (TOG) (1986)

The goal of the research described in this paper is to develop an application-independent presentation tool that automatically designs effective graphical presentations (such as bar charts, scatter plots, and connected graphs) of relational information. Two problems are raised by this goal: The codification of graphic design criteria in a form that can be used by the presentation tool, and the generation of a wide variety of designs so that the presentation tool can accommodate a wide variety of information. The approach described in this paper is based on the view that graphical presentations are sentences of graphical languages. The graphic design issues are codified as expressiveness and effectiveness criteria for graphical languages. Expressiveness criteria determine whether a graphical language can express the desired information. Effectiveness criteria determine whether a graphical language exploits the capabilities of the output medium and the human visual system. A wide variety of designs can be systematically generated by using a composition algebra that composes a small set of primitive graphical languages. Artificial intelligence techniques are used to implement a prototype presentation tool called APT (A Presentation Tool), which is based on the composition algebra and the graphic design criteria.
The Bath algebraic number package
Authors: J. A. Abbott, R. J. Bradford, J. H. Davenport
Venue: Proceedings of the fifth ACM symposium on Symbolic and algebraic computation (1986)

This paper describes a package implemented in REDUCE 3.2 for the manipulation of algebraic numbers. The package regards algebraic numbers as elements of abstract extensions of the rational numbers, not as particular real or complex numbers. We describe in this paper the various design choices that were made, and the current state of the package, as well as future possibilities for enhancement.