ppxscal/embedding_network huggingface dataset:
Memory access patterns of parallel scientific programs
Authors: F. Darema-Rogers, G. F. Pfister, K. So
Venue: Proceedings of the 1987 ACM SIGMETRICS conference on Measurement and modeling of computer systems (1987)

A parallel simulator, PSIMUL, has been used to collect information on the memory access patterns and synchronization overheads of several scientific applications. The parallel simulation method we use is very efficient and it allows us to simulate execution of an entire application program, amounting to hundreds of millions of instructions. We present our measurements on the memory access characteristics of these applications; particularly our observations on shared and private data, their frequency of access and locality. We have found that, even though the shared data comprise the largest portion of the data in the application program, on the average a small fraction of the memory references are to shared data. The low averages do not preclude bursts of traffic to shared memory nor does it rule out positive benefits from caching shared data. We also discuss issues of synchronization overheads and their effect on performance.
Optimal pipelining in supercomputers
Authors: S. R. Kunkel, J. E. Smith
Venue: ACM SIGARCH Computer Architecture News (1986)

This paper examines the relationship between the degree of central processor pipelining and performance. This relationship is studied in the context of modern supercomputers. Limitations due to instruction dependencies are studied via simulations of the CRAY-1S. Both scalar and vector code are studied. This study shows that instruction dependencies severely limit performance for scalar code as well as overall performance.The effects of latch overhead are then considered. The primary cause of latch overhead is the difference between maximum and minimum gate propagation delays. This causes both the skewing of data as it passes along the data path, and unintentional clock skewing due to clock fanout logic. Latch overhead is studied analytically in order to lower bound the clock period that may be used in a pipelined system. This analysis also touches on other points related to latch clocking. This analysis shows that for short pipeline segments both the Earle latch and polarity hold latch give the same clock period bound for both single-phase and multi-phase clocks. Overhead due to data skew and unintentional clock skew are each added to the CRAY-1S simulation model. Simulation results with realistic assumptions show that eight to ten gate levels per pipeline segment lead to optimal overall performance. The results also show that for short pipeline segments data skew and clock skew contribute about equally to the degradation in performance.
A model for naming, addressing and routing
Authors: Bernard M. Hauzeur
Venue: ACM Transactions on Information Systems (TOIS) (1986)

Naming and addressing are areas in which there is still a need for clarification. Many definitions for names, addresses, and routes have been proposed, but the exact relations among these concepts are obscure. A taxonomy of names, addresses, and routes is presented. First, we identify names and routes as the essential concepts of communication. Then, addresses are introduced as an intermediate form that eases the process of mapping between names and routes; an original definition of an address is thus proposed. Relations among names, addresses, and routes are explained with the concept of mapping. On this basis, a general model relating names, addresses, and routes is built and then applied recursively throughout a layered architecture, leading to a layered naming and addressing model which may play the same role for naming and addressing features that the OS1 reference model plays for the definition of services and protocols. Finally, the model is particularized to a typical network architecture. The model may also be applied to non-OSI layered systems; naming, addressing, and routing issues in any network architecture could be a particular instance of this layered model.
TIRS: a topological information retrieval system satisfying the requirements of the Waller-Kraft wish list
Authors: S. Cater, D. Kraft
Venue: Proceedings of the 10th annual international ACM SIGIR conference on Research and development in information retrieval (1987)

Most document retrieval systems based on probabilistic models of feature distributions assume random selection of documents for retrieval. The assumptions of these models are met when documents are randomly selected from the database or when retrieving all available documents. A more suitable model for retrieval of a single document assumes that the best document available is to be retrieved first. Models of document retrieval systems assuming random selection and best-first selection are developed and compared under binary independence and two Poisson independence feature distribution models. Under the best-first model, feature discrimination varies with the number of documents in each relevance class in the database. A weight similar to the Inverse Document Frequency weight and consistent with the best-first model is suggested which does not depend on knowledge of the characteristics of relevant documents.
Computer Science Program Accreditation: the first-year activities of the computing sciences accreditation board
Authors: Taylor Booth Raymond E. Miller
Venue: Communications of the ACM (1987)

This report summarizes the activities of the Computing Sciences Accreditation Board from its inception in 1984 through its first accreditation cycle completed in June 1986. The major activities during this period were directed at developing the CSAB structure necessary to carry out the accreditation process, and at conducting the first round of accreditation visits and actions.
Inference with path resolution and semantic graphs
Authors: Neil V. Murray, Erik Rosenthal
Venue: Journal of the ACM (JACM) (1987)

A graphical representation of quantifier-free predicate calculus formulas in negation normal form and a new rule of inference that employs this representation are introduced. The new rule, path resolution, is an amalgamation of resolution and Prawitz analysis. The goal in the design of path resolution is to retain some of the advantages of both Prawitz analysis and resolution methods, and yet to avoid to some extent their disadvantages. Path resolution allows Prawitz analysis of an arbitrary subgraph of the graph representing a formula. If such a subgraph is not large enough to demonstrate a contradiction, a path resolvent of the subgraph may be generated with respect to the entire graph. This generalizes the notions of large inference present in hyperresolution, clash-resolution, NC-resolution, and UR-resolution. A class of subgraphs is described for which deletion of some of the links resolved upon preserves the spanning property.
Cost benefit analysis of information systems: a survey of methodologies
Authors: Peter G. Sassone
Venue: Proceedings of the ACM SIGOIS and IEEECS TC-OA 1988 conference on Office information systems (1988)

Cost justification has become one of the most important factors influencing the pace of business automation, particularly end user computing. The primary difficulty in cost justification is the evaluation of benefits. This paper identifies and discusses eight methodologies which have evolved to quantify the benefits of information systems. These are: decision analysis, cost displacement/avoidance, structural models, cost of effectiveness analysis, breakeven analysis, subjective analysis, time savings times salary, and the work value model.
Layer Assignment Problem for Three-Layer Routing
Authors: K. C. Chang, H. C. Du
Venue: IEEE Transactions on Computers (1988)

The layer assignment problem for interconnect is the problem of determining which layers should be used for wiring the signal nets so that the number of vias is minimized. The problem is often referred to as the via minimization problem. The problem is considered for three-layer routing, concentrating on one version called the constrained via minimization (CVM3) problem. It is shown that the CVM3 problem is NP-complete and a heuristic algorithm is proposed. The experimental results show that the proposed algorithm is efficient and generates fairly good solutions.
Modeling and Verification of Real-Time Protocols for Broadcast Networks
Authors: P. Jain, S. S. Lam
Venue: IEEE Transactions on Software Engineering (1987)

A class of demand-assigned multiple-access (DAMA) protocols have been proposed for high-speed local area networks (LAN's) that offer integrated services for data, voice, video, and facsimile traffic. These protocols exploit the directionality of signal propagation and implement stringent real-time constraints to achieve collision-freedom. Correct implementation of DAMA protocols will require a very careful analysis of time-dependent interactions using a formal method. To date, most verification methods have been focused on asynchronous communication over point-to-point links.
Distributed system V IPC in LOCUS: a design and implementation retrospective
Authors: B D Fleisch
Venue: ACM SIGCOMM Computer Communication Review (1986)

This paper describes new interprocess communications facilities that have been added to the Locus system [POPEK 81][WALKER 83]. The facilities improve Locus's interprocess communication repertoire by providing distributed support for three separate subsystems from System V UNIX: messages, semaphores, and shared memory. Here we describe these subsystems and their integration into in the Locus architecture.
Transaction management in the R* distributed database management system
Authors: C. Mohan, B. Lindsay, R. Obermarck
Venue: ACM Transactions on Database Systems (TODS) (1986)

This paper deals with the transaction management aspects of the R* distributed database system. It concentrates primarily on the description of the R* commit protocols, Presumed Abort (PA) and Presumed Commit (PC). PA and PC are extensions of the well-known, two-phase (2P) commit protocol. PA is optimized for read-only transactions and a class of multisite update transactions, and PC is optimized for other classes of multisite update transactions. The optimizations result in reduced intersite message traffic and log writes, and, consequently, a better response time. The paper also discusses R*'s approach toward distributed deadlock detection and resolution.
Uncertainty, Energy, and Multiple-Valued Logics
Authors: J P Hayes
Venue: IEEE Transactions on Computers (1986)

The multiple-valued logics obtained by introducing uncertainty and energy considerations into classical switching theory are studied in this paper. First, the nature of uncertain or unknown signals is examined, and two general uncertainty types called U-values and P-values are identified. It is shown that multiple-valued logics composed of U/P-values can be systematically derived from 2-valued Boolean algebra. These are useful for timing and hazard analysis, and provide a rigorous framework for designing gate-level logic simulation programs. Next, signals of the form (v, s) are considered where v and s denote logic level and strength, respectively, and the product vs corresponds to energy flow or power. It is shown that these signals form a type of lattice called a pseudo-Boolean algebra. Such algebras characterize the behavior of digital circuits at a level (the switch level) intermediate between the conventional analog and logical levels. They provide the mathematical basis for an efficient new class of switch-level simulation programs used in MOS VLSI design.
Induction of models under uncertainty
Authors: P Cheeseman
Venue: Proceedings of the ACM SIGART international symposium on Methodologies for intelligent systems (1986)

This paper outlines a procedure for performing induction under uncertainty. This procedure uses a probabilitic representation and uses Bayes' theorem to decide between alternative hypotheses (theories). This procedure is illustrated by a robot with no prior world experience performing induction on data it has gathered about the world. The particular inductive problem is the formation class descriptions both for the tutored and untutored cases. The resulting class definitions are inherenty probabilistic and so do not have any sharply defined membership criterion. This robot example raises some fundamental problems about induction&mdash;particularly it is shown that inductively formed theories are not the best way of making predictions. Another difficulty is the need to provide prior probabilities for the set of possible theories. The main criterion for such priors is a proagmatic one aimed at keeping the theory structure as simple as possible, while still reflecting any structure discovered in the data.
A temporally oriented data model
Authors: Gad Ariav
Venue: ACM Transactions on Database Systems (TODS) (1986)

The research into time and data models has so far focused on the identification of extensions to the classical relational model that would provide it with &ldquo;adequate&rdquo; semantic capacity to deal with time. The temporally oriented data model (TODM) presented in this paper is a result of a different approach, namely, it directly operationalizes the pervasive three-dimensional metaphor for time. One of the main results is thus the development of the notion of the data cube: a three-dimensional and inherently temporal data construct where time, objects, and attributes are the primary dimensions of stored data. TODM's cube adds historical depth to the tabular notions of data and provides a framework for storing and retrieving data within their temporal context. The basic operations in the model allow the formation of new cubic views from existing ones, or viewing data as one moves up and down in time within cubes. This paper introduces TODM, a consistent set of temporally oriented data constructs, operations, and constraints, and then presents TOSQL, a corresponding end-user's SQL-like query syntax. The model is a restricted but consistent superset of the relational model, and the query syntax incorporates temporal notions in a manner that likewise avoids penalizing users who are interested solely in the current view of data (rather than in a temporal perspective). The naturalness of the spatial reference to time and the added semantic capacity of TODM come with a price&mdash;the definitions of the cubic constructs and basic operations are relatively cumbersome. As rudimentary as it is, TODM nonetheless provides a comprehensive basis for formulating an external data model for a temporally oriented database.
A computer science courseware factory
Authors: Michael J. Barnes, R. Hsu, N. Hsu, T. Sun, T. Nguyen, G. Haus, P. D. Smith
Venue: Proceedings of the seventeenth SIGCSE technical symposium on Computer science education (1986)

A model for computer science courseware development within universities is proposed. This model asserts that masters level graduate and undergraduate students are a valuable software development resource that can be utilized to design, prototype, field test, and refine quality courseware. To support this contention four prototype courseware packages are used to briefly describe the Visible Algorithms project at Northridge. These packages provide tutorials on, and graphic animations of: linked list, binary tree, B-tree, and memory management algorithms.
Software engineering practicums: a case study of a senior capstone sequence
Authors: Paul W Oman,  Jr.
Venue: ACM SIGCSE Bulletin (1986)

Increasing demand for software engineers has caused academia to search for means to incorporate software engineering into the existing computer science curriculum. This paper explores traditional software engineering instructional methods and then provides a case study of a two semester practicum modeled after specialized training programs. These practicums, integrated into the University of Idaho Computer Science program, require all computer science seniors to solve "real-world" software engineering problems for actual customers. The practicums serve as quality control exit requirements to ensure that computer science graduates have the software engineering skills required in industry and graduate school. The integrated nature of the computer science program uniquely provides experiential variety while fostering individual responsibility, group interaction skills, and practical experience.
Predictions of the skills required by the systems analyst of the future
Authors: T D Crossman
Venue: ACM SIGCPR Computer Personnel (1986)

It can be expected that people's opinions about the future will differ. Consequently a high degree of concurrence cannot be anticipated if a mixed group of academics and practitioners are asked to forecast aspects of the future of application systems development.
Specification versus implementation based on Estelle
Authors: L Kovacs, A Ercsényi
Venue: ACM SIGCOMM Computer Communication Review (1986)

The main problems of the ESTELLE communication protocol specification language are discussed by analyzing the present version of the ISO draft proposal language definition. Two different directions of the future development of ESTELLE are proposed. The first is the creation of the exact, formal semantic definition. The second direction of the language development leads to the high-level implementation languages. The separability technique (separate compilation) which can be used in the case of ESTELLE documents is investigated and a different structuring principle is suggested. The inner contradiction of the module instantiation is revealed and the construction of an alternative specification is suggested. The ESTELLE process concept is compared with an implementation process concept. Analyzing the structures of the protocol specifications it is pointed out that some implementation considerations are smuggled into the protocol specifications described in ESTELLE.
An O(lg n) expected rounds randomized Byzantine generals protocol
Authors: G Bracha
Venue: Proceedings of the seventeenth annual ACM symposium on Theory of computing (1985)

Byzantine Generals protocols enable processes to reliably broadcast messages in the presence of faulty processes. These protocols are run in a system of consists of n processes, t of which are faulty. The protocols are conducted in synchronous rounds of message exchange. We show that, without using cryptography, for t = n/(3 + &dgr;), there is a randomized protocol with &Ogr;(lg n) expected number of rounds. If we allow cryptographic methods, then, for t = n / (2 + &dgr;), there is a randomized protocol with &Ogr;(lg n) expected number of rounds. This is an improvement on the lower bound of t + 1 rounds required for det &hellip; &hellip; previous result of t/lg n expected nu rounds for randomized protocols.
Describing and analyzing distributed software system designs
Authors: George S. Avrunin, Jack C. Wileden
Venue: ACM Transactions on Programming Languages and Systems (TOPLAS) (1985)

In this paper we outline an approach to describing and analyzing designs for distributed software systems. A descriptive notation is introduced, and analysis techniques applicable to designs expressed in that notation are presented. The usefulness of the approach is illustrated by applying it to a realistic distributed software-system design problem involving mutual exclusion in a computer network.
A simplex algorithm whose average number of steps is bounded between two quadratic functions of the smaller dimension
Authors: Ilan Adler, Nimrod Megiddo
Venue: Journal of the ACM (JACM) (1985)

It has been a challenge for mathematicians to confirm theoretically the extremely good performance of simplex-type algorithms for linear programming. In this paper the average number of steps performed by a simplex algorithm, the so-called self-dual method, is analyzed. The algorithm is not started at the traditional point (1, &hellip; , l)T, but points of the form (1, &egr;, &egr;2, &hellip;)T, with &egr; sufficiently small, are used. The result is better, in two respects, than those of the previous analyses. First, it is shown that the expected number of steps is bounded between two quadratic functions c1(min(m, n))2 and c2(min(m, n))2 of the smaller dimension of the problem. This should be compared with the previous two major results in the field. Borgwardt proves an upper bound of O(n4m1/(n-1)) under a model that implies that the zero vector satisfies all the constraints, and also the algorithm under his consideration solves only problems from that particular subclass. Smale analyzes the self-dual algorithm starting at (1, &hellip; , 1)T. He shows that for any fixed m there is a constant c(m) such the expected number of steps is less than c(m)(ln n)m(m+1); Megiddo has shown that, under Smale's model, an upper bound C(m) exists. Thus, for the first time, a polynomial upper bound with no restrictions (except for nondegeneracy) on the problem is proved, and, for the first time, a nontrivial lower bound of precisely the same order of magnitude is established. Both Borgwardt and Smale require the input vectors to be drawn from spherically symmetric distributions. In the model in this paper, invariance is required only under certain
Atmospheric illumination and shadows
Authors: Nelson L. Max
Venue: Proceedings of the 13th annual conference on Computer graphics and interactive techniques (1986)

The shadow volume algorithm of Frank Crow was reorganized to provide information on the regions of illuminated space in front of each visible surface. This information is used to calculate the extra intensity due to atmospheric scattering, so when the atmosphere is partly in shadow, columns of scattered light will be visible. For efficiency in sorting the shadow edges, the image is computed in polar coordinates.
Implementing an elementary function library
Authors: Peter Thompson
Venue: ACM SIGNUM Newsletter (1987)

This paper describes the author's experience of implementing a comprehensive library of elementary functions in the INMOS proprietry language occam, to support scientific and engineering applications of transputers.
Microprocessor sequence revitalization
Authors: W. E. Mattis
Venue: ACM SIGCSE Bulletin (1988)

The rationale for the revamping of microprocessor courses serving the Electrical Engineering and Computer Science Departments at Villanova University is described, including the choice of one processor for instruction, the sequencing of lecture material, and the development of a laboratory to reinforce the lecture material.
Automated Software Quality Assurance
Authors: Harry M. Sneed, András Mérey
Venue: IEEE Transactions on Software Engineering (1985)

This paper describes a family of tools which not only supports software development, but also assures the quality of each software product from the requirements definition to the integrated system. It is based upon an explicit definition of the design objectives and includes specification verification, design evaluation, static program analysis, dynamic program analysis, integration test auditing, and configuration management.
A manager's guide to integrated services digital network
Authors: James C. Brancheau, Justus D. Naumann
Venue: ACM SIGMIS Database (1987)

Large businesses are becoming increasingly dependent on telecommunications for their continued survival. A recent development in telecommunications which will have enormous strategic impact through the next decade is the concept of integrated services digital network (ISDN). ISDN's strategic value is tied to its goal of providing low cost voice, data, and video access to nearly every home and office in the United States, and eventually, the world. This paper describes what ISDN means and explores many of the issues surrounding its evolution, development, and potential use as a strategic weapon. To support the discussion of ISDN, the current public telecommunications network is described in some detail. Market and competitive forces, motivating and inhibiting the evolution toward ISDN are discussed with some observations on what the future may bring. Finally, planning considerations with respect to ISDN and its strategic implications for business are discussed.