ppxscal/embedding_network huggingface dataset:
Deterministic execution testing of concurrent Ada programs
Authors: R. Carver, K. C. Tai
Venue: Proceedings of the conference on Tri-Ada '89: Ada technology in context: application, development, and deployment (1989)

An execution of a concurrent program P exercises a sequence of synchronization events, called a synchronization sequence or a SYN-sequence. This non-deterministic execution behavior creates a problem during the testing phase of P: when testing P with input X, a single execution is insufficient to determine the correctness of P with input X. In this paper, we show how to accomplish deterministic execution testing of a concurrent Ada program according to a given SYN-sequence. We first define the format of a SYN-sequence which provides sufficient information for deterministic execution. Then we show how to transform a concurrent Ada program P into a slightly different program P* (also written in Ada) so that an execution of P* with (X,S) as input, where X and S are an input and SYN-sequence of P respectively, determines whether or not S is feasible for P with input X and produces the same result as P with input X and SYN-sequence S would, provided that S is feasible. Tools for transforming concurrent Ada programs for deterministic execution testing are described.
Preferences for power in expert systems by novice users
Authors: Michael D. Coovert, Kathleen McNelis, Kamesh Ramakrishna, Eduardo Sala
Venue: ACM SIGCHI Bulletin (1988)

The focus in building expert systems has typically been to build them to be as powerful as possible. These systems continue to impact directly or indirectly on nearly every aspect of our lives. Among the myriad applications which currently exist, expert systems have been designed to diagnose medical problems (Buchnan amp; Shortliffe, 1984), instruct students (Freedman, 1987), and schedule airline reservations (Rich, 1981.
Analytic response time model for distributed systems
Authors: Janice H. Cook, Leo H. Groner
Venue: ACM SIGAPL APL Quote Quad (1990)

Network designers are faced with a combinatorial explosion of choices not only among various vendors' workstations, hosts and servers, but also among application distribution strategies, communication media, communication protocols, and network topologies. To study performance trade-offs among various designs, the authors have developed a generic system thruput and response time model for distributed systems. We have applied the model to actual customer networks. The modeller describes the system in a language of model statements describing operations, resources, submodels, parameters and transactions flows. Model statements are &ldquo;compiled&rdquo; into arrays that form the input to the analytical queueing network model. The modeling package is written in APL2 and is based on an earlier VSAPL package developed for manufacturing planning. Since the package is designed with an open set of submodel types, and since APL2 is portable across many architectures and operating systems, we can easily integrate non-APL2 code.
A procedural semantics for well founded negation in logic programs
Authors: K. A. Ross
Venue: Proceedings of the eighth ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems (1989)

We introduce global SLS-resolution, a procedural semantics for well-founded negation as defined by Van Gelder, Ross and Schlipf. Global SLS-resolution extends Prsymusinski's SLS-resolution, and may be applied to all programs, whether locally stratified or not.1 Global SLS-resolution is defined in terms of global trees, a new data structure representing the dependence of goals on derived negative subgoals. We prove that global SLS-resolution is sound with respect to the well-founded semantics, and complete for non-floundering queries.
How to make ad-hoc polymorphism less ad hoc
Authors: P. Wadler, S. Blott
Venue: Proceedings of the 16th ACM SIGPLAN-SIGACT symposium on Principles of programming languages (1989)

This paper presents type classes, a new approach to ad-hoc polymorphism. Type classes permit overloading of arithmetic operators such as multiplication, and generalise the &ldquo;eqtype variables&rdquo; of Standard ML. Type classes extend the Hindley/Milner polymorphic type system, and provide a new approach to issues that arise in object-oriented programming, bounded type quantification, and abstract data types. This paper provides an informal introduction to type classes, and defines them formally by means of type inference rules.
Updating derived relations: detecting irrelevant and autonomously computable updates
Authors: José A. Blakeley, Neil Coburn, Per-:1Vke Larson
Venue: ACM Transactions on Database Systems (TODS) (1989)

Consider a database containing not only base relations but also stored derived relations (also called materialized or concrete views). When a base relation is updated, it may also be necessary to update some of the derived relations. This paper gives sufficient and necessary conditions for detecting when an update of a base relation cannot affect a derived relation (an irrelevant update), and for detecting when a derived relation can be correctly updated using no data other than the derived relation itself and the given update operation (an autonomously computable update). The class of derived relations considered is restricted to those defined by PSJ-expressions, that is, any relational algebra expressions constructed from an arbitrary number of project, select and join operations (but containing no self-joins). The class of update operations consists of insertions, deletions, and modifications, where the set of tuples to be deleted or modified is specified by a selection condition on attributes of the relation being updated.
Three steps to views: extending the object-oriented paradigm
Authors: J. J. Shiling, P. F. Sweeney
Venue: Conference proceedings on Object-oriented programming systems, languages and applications (1989)

At the core of any sophisticated software development and maintenance environment is a large mass of complex data. The data (the central data of the environment) is composed of smaller sets of data that can be related in complicated and often subtle ways. The user or developer of the environment will be more effective if they are able to deal with conceptual slices, or views, of the large, complex structure. This paper presents an architectural building block for object-based software environments based on the views concept. The building block allows the construction of global abstractions that describe unified behavior of large sets of objects. The basis of the architecture relies on extending the object-oriented paradigm in three steps: (1) defining multiple interfaces in object classes; (2) controlling visibility of instance variables; and (3) allowing multiple copies of an instance variable to occur within an object instance. This paper focuses on the technical aspects of the views approach.
Increasing availability under mutual exclusion constraints with dynamic vote reassignment
Authors: Daniel Barbara, Hector Garcia-Molina, Annemarie Spauster
Venue: ACM Transactions on Computer Systems (TOCS) (1989)

Voting is used commonly to enforce mutual exclusion in distributed systems. Each node is assigned a number of votes, and only the group with a majority of votes is allowed to perform a restricted operation. This paper describes techniques for dynamically reassigning votes upon node or link failure, in an attempt to make the system more resilient to future failures. We focus on autonomous methods for achieving this, that is, methods that allow the nodes to make independent choices about changing their votes and picking new vote values, rather than group consensus techniques that require tight coordination among the remaining nodes. Protocols are given which allow nodes to install new vote values while still maintaining mutual exclusion requirements. The lemmas and theorems to validate the protocols are presented. A simple example shows how to apply the method to a database object-locking scheme; the protocols, however, are versatile and general purpose, and can be used for any application requiring mutual exclusion. In addition, policies are presented that allow nodes to autonomously select their new vote values. Simulation results are presented comparing the autonomous methods to static vote assignments and to group consensus strategies. These results demonstrate that under high failure rates, dynamic vote reassignment shows great improvement over a static assignment of votes in terms of availability. In addition, many autonomous methods for determining a new vote assignment yield almost as much availability as a group consensus method and at the same time are faster and more flexible.
An object addressing mechanism for statically typed languages with multiple inheritance
Authors: R. C. H. Conner, A. Dearle, R. Morrison, A. L. Brown
Venue: Conference proceedings on Object-oriented programming systems, languages and applications (1989)

In this paper we are concerned with addressing techniques for statically typed languages with multiple inheritance. The addressing techniques are responsible for the efficient implementation of record field selection. In object-oriented languages, this record selection is equivalent to the access of methods. Thus, the efficiency of these techniques greatly affects the overall performance of an object-oriented language. We will demonstrate that addresses, in such systems, cannot always be calculated statically and show how symbol tables have been used as address maps at run time. The essence of the paper is a new addressing technique that can statically calculate either the address of a field or the address of the address of the field. This technique is powerful enough to support an efficient implementation of multiple inheritance with implicit subtyping as described by Cardelli.
Compact distributed data structures for adaptive routing
Authors: B. Awerbuch, A. Bar-Noy, N. Linial, D. Peleg
Venue: Proceedings of the twenty-first annual ACM symposium on Theory of computing (1989)

In designing a routing scheme for a communication network it is desirable to use as short as possible paths for routing messages, while keeping the routing information stored in the processors' local memory as succinct as possible. The efficiency of a routing scheme is measured in terms of its stretch factor - the maximum ratio between the cost of a route computed by the scheme and that of a cheapest path connecting the same pair of vertices. This paper presents a family of adaptive routing schemes for general networks. The hierarchical schemes H Sk (for every fixed k &ge; 1) guarantee a stretch factor of O (k2 &middot; 3k) and require storing at most O (knk log n) bits of routing information per vertex. The new important features, that make the schemes appropriate for adaptive use, are applicability to networks with arbitrary edge costs; name-independence, i.e., usage of original names; a balanced distribution of the memory; an efficient on-line distributed preprocessing.
Average case selection
Authors: Walter Cunto, J. Ian Munro
Venue: Journal of the ACM (JACM) (1989)

It is shown that n + k - O(1) comparisons are necessary, on average, to find the kth smallest of n numbers (k &lne; n/2). This lower bound matches the behavior of the technique of Floyd and Rivest to within a lower-order term. 7n/4 &plusmn; o(n) comparisons, on average, are shown to be necessary and sufficient to find the maximum and median of a set. An upper bound of 9n/4 &plusmn; o(n) and a lower bound of 2n - o(n) are shown for the max-min-median problem.
LFP: a logic for linguistic descriptions and an analysis of its complexity
Authors: William C. Rounds
Venue: Computational Linguistics (1988)

We investigate the weak expressive power of a notation using first-order logic, augmented with a facility for recursion, to give linguistic descriptions. The notation is precise and easy to read, using ordinary conventions of logic. Two versions of the notation are presented. One, called CLFP, speaks about strings and concatenation, and generates the class EXPTIME of languages accepted by Turing machines in time 2cn for some c > 0. The other, called ILFP, speaks about integer positions in strings, and generates the class PTIME of languages recognizable in polynomial time. An application is given, showing how to code Head Grammars in ILFP, showing why these grammars generate only polynomial time languages.
A phased programming paradigm
Authors: C. T. Zahn
Venue: ACM SIGCSE Bulletin (1988)

Correctness and efficiency are both legitimate concerns in program development. Through an extended example we present a multi-phase paradigm which encourages early algorithms to be abstract and maximally nondeterministic in the spirit of Dijkstra's guarded commands [4] but which caters equally for correctness, termination, data representation, efficiency and practical implementation in a low level language.
Group Theoretic Signature Analysis
Authors: Bella Bose
Venue: IEEE Transactions on Computers (1990)

A new class of data-compression techniques called group-theoretic signature analysis (GTSA) for testing a logic network is proposed, and the fault coverage of the method is analyzed. This method is a generalization of accumulator compression testing. Built-in-self-test for processor environments is feasible with GTSA.
APL\?
Authors: Roger K. W. Hui, Kenneth E. Iverson, E. E. McDonnell, Arthur T. Whitney
Venue: ACM SIGAPL APL Quote Quad (1990)

This paper describes a version of APL based upon the dictionary [1], but significantly simplified and enhanced, and directly usable on any machine that provides ASCII characters. It also describes salient features of a C implementation that has been tested on several machines, and is available as freeware. There have been four primary motivations for this work: To provide an APL system for use in teaching mathematics and related topics that is modern, free, and transportable. To devise a spelling scheme based on the ASCII alphabet that preserves the major advantages of the one-letter words based on the special alphabet commonly used in APL. To exploit the advantages of breaking from the strict conformance with earlier APL that is normally obligatory in commercial systems. To explore an unusual style of C programming that makes heavy use of pre-processing facilities. Examples of the use of the language in a variety of topics are provided in an appendix. We are indebted to a number of colleagues for advice and help: Anthony Howe, David Steinbrook, Bob Bernecky, Mark Czerwinski, L.J. Dickey, Jiri Dvorak, James Hui, Eric Iverson, Paul Jackson, and Roland Pesch.
Developing knowledge-based systems: reorganizing the system development life cycle
Authors: John R. Weitzel, Larry Kerschberg
Venue: Communications of the ACM (1989)

Through methodological evolution, the development of the Knowledge-Based Development Life Cycle is supported. In this methodology, processes replace phases and stages and during system development, dynamic activation of processes allows the system to evolve.
Memory-reference characteristics of multiprocessor applications under MACH
Authors: A. Agawal, A. Gupta
Venue: Proceedings of the 1988 ACM SIGMETRICS conference on Measurement and modeling of computer systems (1988)

Shared-memory multiprocessors have received wide attention in recent times as a means of achieving high-performance cost-effectively. Their viability requires a thorough understanding of the memory access patterns of parallel processing applications and operating systems. This paper reports on the memory reference behavior of several parallel applications running under the MACH operating system on a shared-memory multiprocessor. The data used for this study is derived from multiprocessor address traces obtained from an extended ATUM address tracing scheme implemented on a 4-CPU DEC VAX 8350. The applications include parallel OPS5, logic simulation, and a VSLI wire routing program. Among the important issues addressed in this paper are the amount of sharing in user programs and in the operating system, comparing the characteristics of user and system reference patterns, sharing related to process migration, and the temporal, spatial, and processor locality of shared blocks. We also analyze the impact of shared references on cache coherence in shared-memory multiprocessors.
The Probabilistic Peaking Effect of Viewed Angles and Distances with Application to 3-D Object Recognition
Authors: J. Ben-Arie
Venue: IEEE Transactions on Pattern Analysis and Machine Intelligence (1990)

Two novel probabilistic models for viewed angles and distances are derived using an observability sphere method. The method, which is based on the assumption that the prior probability density is isotropic for all viewing orientations, can be used for the computation of observation probabilities for object's aspects, features, and probability densities of their quantitative attributes. Using the sphere, it is discovered that the probability densities of viewed angles, distances, and even projected curvature have sharp peaks at their original values. From this peaking effect, it is concluded that in most cases, the values of angles and distances are being altered only slightly by the imaging process, and they can still serve as a strong cue for model-based recognition. The probabilistic models for 3-D object recognition from monocular images are used. To form the angular elements that are needed, the objects are represented by their linear features and specific points primitives. Using the joint density model of angles and distances, the probabilities of initial matching hypotheses and mutual information coefficients are estimated. These results are then used for object recognition by optimal matching search and stochastic labeling schemes. Various synthetic and real objects are recognized by this approach.
AS/RS amd warehouse modeling
Authors: D. J. Muller
Venue: Proceedings of the 21st conference on Winter simulation (1989)

The computer simulation of Automated Storage and Retrieval Systems (AS/RS) and warehousing systems often present the modeler with numerous issues dealing with modeling strategies. The modeler must decide the level of detail needed to represent the various components of the system in order to obtain results which can be used in the evaluation process. This paper presents some of the warehouse components to be considered in modeling warehouse applications. It then discusses the different objectives modelers have in modeling storage facilities and the general concepts behind three modeling approaches which vary in complexity. The paper concludes with an example of the detailed warehouse modeling approach for tracking individual products and storage locations.
Using partial fraction formulas to sum some slowly convergent series analytically for molecular integral calculations
Authors: M. P. Barnett
Venue: ACM SIGSAM Bulletin (1989)

Two sets of rational expressions, needed for quantum chemical calculations, have been constructed by mechanical application of partial fraction and polynomial operations on a CYBER 205. The algorithms were coded in FORTRAN, using simple array manipulation. The results suggest extensions that could be tackled with general algebraic manipulation programs.
Diversity in the use of electronic mail: a preliminary inquiry
Authors: Wendy E. Mackay
Venue: ACM Transactions on Information Systems (TOIS) (1988)

This paper describes a series of interviews that examine the ways that professional office workers use electronic mail to manage their daily work. The purpose is to generate hypotheses for future research. A number of implications for the design of flexible mail systems are discussed. Two principal claims are made. First, the use of electronic mail is strikingly diverse, although not infinitely so. Individuals vary both in objective measures of mail use and in preferred strategies for managing work electronically. Feelings of control are similarly diverse and are related to the size of the user's inbox, numbers of folders, and subscriptions to distribution lists. This diversity implies that one's own experiences with electronic mail are unlikely to provide sufficient understanding of other's uses of mail. Mail designers should thus seek flexible primitives that capture the important dimensions of use and provide flexibility for a wide range of users. The second claim is that electronic mail is more than just a communication system. Users archive messages for subject retrieval, prioritize messages to sequence work activities, and delegate tasks via mail. A taxonomy of work management is proposed in which mail is used for information management, time management, and task management activities. Directions for future research are suggested.
Productivity enhancement from computer-mediated communication: a systems contingency approach
Authors: Starr Roxanne Hiltz
Venue: Communications of the ACM (1988)

A systems contingency approach to social impacts of computing predicts that productivity enhancement will be a function of a complex interaction of social and technical systems.
Dataflow Computing Models, Languages, and Machines for Intelligence Computations
Authors: J. Herath, Y. Yamaguchi, N. Saito, T. Yuba
Venue: IEEE Transactions on Software Engineering (1988)

The authors compare dataflow computing models, languages, and dataflow computing machines for numerical and nonnumerical computations. The high-level-language-graph transformations that must be performed to achieve high performance for numerical and nonnumerical programs executed in a dataflow computing environment are described for Lisp, using the DCBL transformations. Some general problems of dataflow computing machines are discussed. Performance evaluation measurements obtained by executing benchmark programs in the ETL nonnumerical dataflow computing environment, the EM-3, are presented.
How slow is one gigabit per second?
Authors: Craig Partridge
Venue: ACM SIGCOMM Computer Communication Review (1989)

At first blush, one would expect that increasing data network transfer rates by two orders of magnitude (from the ubiquitous 10 Mbit speed of today's LANs to the greater than 1 gigabit-per-second speeds we expect of networks in the early 1990s) would severely impact our choice of network protocols and architectures. This report presents the strawman argument that, in fact, moving to one-gigabit data rates presents surprisingly few problems.
Building analytical models into an interactive performance prediction tool
Authors: D. Arapattu, D. Gannon
Venue: Proceedings of the 1989 ACM/IEEE conference on Supercomputing (1989)

In this paper we describe an interactive tool designed for performance prediction of parallel programs. Static performance prediction, in general, is a very difficult task. In order to avoid some inherent problems, we concentrate on reasonably structured scientific programs. Our prediction system, which is built as a sub-system of a larger interactive environment, uses a parser, dependence analyzer, database and an X-window based front end in analyzing programs. The system provides the user with execution times of different sections of programs. When there are unknowns involved, such as number of processors or unknown loop bounds, the output is an algebraic expression in terms of these variables. We propose a simple analytical model as an attempt to predict performance degradation due to data references in hierarchical memory systems. The predicted execution times of some Lawrence Livermore loop kernels are given together with the experimental values obtained by executing the loops on Alliant FX/8.