ppxscal/embedding_network huggingface dataset:
Computing Optimal Checkpointing Strategies for Rollback and Recovery Systems
Authors: P. L'Ecuyer, J. Malenfant
Venue: IEEE Transactions on Computers (1988)

A numerical approach for computing optimal dynamic checkpointing strategies for general rollback and recovery systems is presented. The system is modeled as a Markov renewal decision process. General failure distributions, random checkpointing durations, and reprocessing-dependent recovery times are allowed. The aim is to find a dynamic decision rule to maximize the average system availability over an infinite time horizon. A computational approach to approximate such a rule is proposed. This approach is based on value-iteration stochastic dynamic programming with spline or finite-element approximation of the value and policy functions. Numerical illustrations are provided.
Omega A Data Flow Analysis Tool for the C Programming Language
Authors: Cindy Wilson, Leon J. Osterweil
Venue: IEEE Transactions on Software Engineering (1985)

This paper describes Omega, a prototype system designed to analyze data flow in C programs. Omega is capable of detecting certain types of common programming errors, or assuring their absence. Omega also addresses the problems of analyzing pointer variables.
Delay analysis of a window tree conflict resolution algorithm in a local area network environment
Authors: George C. Polyzos, Mart L. Molle
Venue: Proceedings of the 1987 ACM SIGMETRICS conference on Measurement and modeling of computer systems (1987)

Expressions are found for the throughput and delay performance of a Tree Conflict Resolution Algorithm that is used in a Local Area Network with carrier sensing (and possibly also collision detection). We assume that Massey's constant size window algorithm is used to control access to the channel, and that the resulting conflicts (if any) are resolved using a Capetanakis-like preorder traversal tree algorithm with d-ary splitting. We develop and solve functional equations for various performance metrics of the system and apply the &ldquo;Moving Server&rdquo; technique to calculate the main component of the delay. Our results compare very favorably with those for CSMA protocols, which are commonly used in Local Area Networks that support sensing.
A database design methodology and tool for information systems
Authors: Roger King, Dennis McLeod
Venue: ACM Transactions on Information Systems (TOIS) (1985)

A model and methodology for describing the information objects in an office information system and how such objects flow among the components of such a system are presented. The model and methodology support the specification of information objects at multiple levels of abstraction. An interactive prototype design tool based on the methodology and model has been designed and experimentally implemented.
Rectilinear Shortest Paths and Minimum Spanning Trees in the Presence of Rectilinear Obstacles
Authors: Ying-Fung Wu, Peter Widmayer, Martine D. F. Schlag, C. K. Wong
Venue: IEEE Transactions on Computers (1987)

We study the rectilinear shortest paths and minimum spanning tree (MST) problems for a set of points in the plane in the presence of rectilinear obstacles. We use the track graph, a suitably defined grid-like structure, to obtain efficient solutions for both problems. The track graph consists of rectilinear tracks defined by the obstacles and the points for which shortest paths and a minimum spanning tree are sought. We use a growth process like Dijkstra's on the track graph to find shortest paths from any point in the set to all other points (the one-to-all shortest paths problem). For the one-to-all shortest paths problem for n points we derive an O(n min {log n, log e} + (e + k) log t) time algorithm, where e is the total number of edges of all obstacles, t is the number of extreme edges of all obstacles, and k is the number of intersections among obstacle tracks (all bounds are for the worst case). The MST for the points is constructed also in time O(n log n + (e + k) log t) by a hybrid method of searching for shortest paths while simultaneously constructing an MST. An interesting application of the MST algorithm is the approximation of Steiner trees in graphs.
The senior information systems design project seminar
Authors: Mary Sumner
Venue: ACM SIGCSE Bulletin (1987)

One of the challenges of teaching MIS is preparing students to apply the knowledge they have gained in a real project. Although they have developed proficiency in problem-solving, structured design techniques, and programming during course work, many MIS students have never interviewed a user or been asked to make design changes at a user's request. In addition, many students have never had to work on a project team, manage schedules, and meet project deadlines.The senior information systems design project course provides students with an opportunity to apply systems concepts and techniques in the design of an information system. Students identify &ldquo;live&rdquo; projects and work on project teams. In the past, many of these projects have been programming design and implementation projects provided by local industry. However, in large-scale projects, students could not start with problem definition, proceed to requirements specification, and complete detailed design, because all of this could not be accomplished in a single term. As a result, they would do segments of larger projects.With the advent of the microcomputer, however, many smaller scale projects became available in offices seeking to automate records management, routine accounting, and other office automation systems. These projects created an opportunity for students to do an entire project, from systems analysis to detailed design.The purpose of this paper is to describe the objectives and procedures of the information systems design project seminar and to discuss the nature and scope of design projects conducted in university offices during the fall, 1985 quarter. The paper will describe the respective roles of student systems analysts and users, the systems development practices followed, and some of the successes and pitfalls of the experience.
RiTSE: The reactor trip simulation environment
Authors: S Epstein
Venue: Issue 97 (July 1986) (1986)

Management Analysis Company, located in San Diego, is a general consulting corporation dealing almost exclusively with nuclear power generation.
Spanner: A Tool for the Specification, Analysis, and Evaluation of Protocols
Authors: Sudhir Aggarwal, Daniel Barbará, Kalman Z. Meth
Venue: IEEE Transactions on Software Engineering (1987)

SPANNER is a software package for the specification, analysis, and evaluation of protocols. It is based on a mathematical model of coordinating processes called the selection/resolution model.
The MIRRORS/II simulator
Authors: C. Lynne D'Autrechy, James A. Reggia
Venue: Proceedings of the 20th annual symposium on Simulation (1987)

MIRRORS/II is a software system for developing connectionist models. This paper discusses the unique features of MIRRORS/II: application independence, specification language, multiple target languages, extensibility, and accumulative resources. A detailed example of the use of MIRRORS/II is given. Finally, MIRRORS/II is compared with other existing connectionist modelling systems and future plans are discussed.
Processing encrypted data
Authors: Niv Ahituv, Yeheskel Lapid, Seev Neumann
Venue: Communications of the ACM (1987)

A severe problem in the processing of encrypted data is that very often, in order to perform arithmetic operations on the data, one has to convert the data back to its nonencrypted origin before performing the required operations. This paper addresses the issue of processing data that have been encrypted while the data are in an encrypted mode. It develops a new approach for encryption models that can facilitate the processing of such data. The advantages of this approach are reviewed, and a basic algorithm is developed to prove the feasibility of the approach.
Problems and some solutions in customization of natural language database front ends
Authors: Fred J. Damerau
Venue: ACM Transactions on Information Systems (TOIS) (1985)

This paper is concerned with some of the issues arising in the development of a domain-independent English interface to IBM SQL-based program products. The TQA system falls into the class of multilayered natural language processing systems. As a result, there is a large number of potential points at which customization to a particular database can be done. Of these, we discuss procedures that affect the reader, the lexicon, the lowest level of grammar rules, the semantic interpreter, and the output formatter. Our tests lead us to believe that the approach we are taking will make it possible for database administrators to generate robust English interfaces to particular databases without help from linguistic experts.
Integration of a primal simplex network algorithm with a large-scale mathematical programming system
Authors: J. A. Tomlin, J. S. Welch
Venue: ACM Transactions on Mathematical Software (TOMS) (1985)

In this paper we discuss the implementation of a primal simplex algorithm for network problems in the MPSIII mathematical programming system. Because of the need to interface with the rest of the MPS this implementation is unorthodox, but computationally effective, and has a number of advantages over &ldquo;stand alone&rdquo; network optimizers. It is argued that a similar approach is appropriate for other general-purpose mathematical programming systems, and has applications beyond pure network optimization.
Optimization of join operations in horizontally partitioned database systems
Authors: Arie Segev
Venue: ACM Transactions on Database Systems (TODS) (1986)

This paper analyzes the problem of joining two horizontally partitioned relations in a distributed database system. Two types of semijoin strategies are introduced, local and remote. Local semijoins are performed at the site of the restricted relation (or fragment), and remote semijoins can be performed at an arbitrary site. A mathematical model of a semijoin strategy for the case of remote semijoins is developed, and lower bounding and heuristic procedures are proposed. The results of computational experiments are reported. The experiments include an analysis of the heuristics' performance relative to the lower bounds, sensitivity analysis, and error analysis. These results reveal a good performance of the heuristic procedures, and demonstrate the benefit of using semijoin operations to reduce the size of fragments prior to their transmission. The algorithms for the case of remote semijoins were found to be superior to the algorithms for the case of local semijoins. In addition, we found that the estimation accuracy of the selectivity factors has a significant effect on the incurred communication cost.
Using prototypical objects to implement shared behavior in object-oriented systems
Authors: Henry Lieberman
Venue: ACM SIGPLAN Notices (1986)

A traditional philosophical controversy between representing general concepts as abstract sets or classes and representing concepts as concrete prototypes is reflected in a controversy between two mechanisms for sharing behavior between objects in object oriented programming languages. Inheritance splits the object world into classes, which encode behavior shared among a group of instances, which represent individual members of these sets. The class/instance distinction is not needed if the alternative of using prototypes is adopted. A prototype represents the default behavior for a concept, and new objects can re-use part of the knowledge stored in the prototype by saying how the new object differs from the prototype. The prototype approach seems to hold some advantages for representing default knowledge, and incrementally and dynamically modifying concepts. Delegation is the mechanism for implementing this in object oriented languages. After checking its idiosyncratic behavior, an object can forward a message to prototypes to invoke more general knowledge. Because class objects must be created before their instances can be used, and behavior can only be associated with classes, inheritance fixes the communication patterns between objects at instance creation time. Because any object can be used as a prototype, and any messages can be forwarded at any time, delegation is the more flexible and general of the two techniques.
Two Access Methods Using Compact Binary Trees
Authors: W. de Jonge, A. S. Tanenbaum, R. P. van de Riet
Venue: IEEE Transactions on Software Engineering (1987)

It is shown how a highly compact representation of binary trees can be used as the basis of two access methods for dynamic files, called BDS-trees and S-trees, respectively. Both these methods preserve key-order and offer easy and efficient sequential access. They are different in the way the compact binary trees are used for searching. With a BDS-tree the search is a digital search using binary digits. Although the S-tree search is performed on a bit-by-bit basis as well, it will appear to be slightly different. Actually, with S-trees the compact binary trees are used to represent separators at low storage costs. As a result, the fan-out, and thus performance, of a B-tree can be improved by using within each index page an S-tree for representing separators efficiently.
Permutation groups in NC
Authors: L. Babai, E. Luks, A. Seress
Venue: Proceedings of the nineteenth annual ACM symposium on Theory of computing (1987)

We show that the basic problems of permutation group manipulation admit efficient parallel solutions. Given a permutation group G by a list of generators, we find a set of NC-efficient strong generators in NC. Using this, we show, that the following problems are in NC: membership in G; determining the order of G; finding the center of G; finding a composition series of G along with permutation representations of each composition factor. Moreover, given G, we are able to find the pointwise stabilizer of a set in NC. One consequence is that isomorphism of graphs with bounded multiplicity of eigenvalues is in NC. The analysis of the algorithms depends, in several ways, on consequences of the classification of finite simple groups.
Research into fuzzy extensions of information retrieval
Authors: Donald H Kraft
Venue: ACM SIGIR Forum (1986)

Modern computerized information retrieval systems consist of mechanisms to acquire, describe (e.g., index), and store "documents", and to receive, analyze, and respond to queries for information for users. A key element is the index language, by which the users (or user intermediaries) and indexers can communicate. Modern technology allows natural language processing mechanisms to begin to be incorporated in the sense of matching terms found in the free text specification of the query and the free text within the document.
Turing Plus: a comparison with C and Pascal
Authors: S. Perelgut, James R. Cordy
Venue: ACM SIGPLAN Notices (1988)

It is desirable to do systems programming in a high-level language. C is attractive since it yields efficient machine code without placing many restrictions on the programmer. This lack of restrictions and language-supported checking, however, can make C code unreadable and unmaintainable. Pascal is attractive since it provides strong type checking in a relatively elegant package but Pascal compilers don't produce efficient code. Turing Plus offers the advantages of both these languages, including efficient machine code and strong type checking. It also has a number of other features that make it a very attractive alternative. For example, Turing Plus offers controlled access to machine-dependencies, type checked separate compilation, linkage to external routines, language-specified concurrency and exception handling. Portable compilers with replaceable code generators (allowing easy access to cross-compilation) are available and a Turing Plus to C translator is under construction to allow fast portability to all systems supporting C compilers.
Adaptive linear information retrieval models
Authors: P. Bollmann, S. K. M. Wong
Venue: Proceedings of the 10th annual international ACM SIGIR conference on Research and development in information retrieval (1987)

Missing, non-applicable and imprecise values arise frequently in Office Information Systems. There is a need to treat them in a consistent and useful manner. This paper proposes a method and gives the precise semantics of the retrieval operations in a system where imprecision is allowed. It also suggests a way to handle the uncertainty introduced by imprecise data values.
Defining constraints graphically
Authors: A. Borning
Venue: ACM SIGCHI Bulletin (1986)

A number of constraint-oriented, interactive graphical systems have been constructed. A typical problem in such systems is that, to define a new kind of constraint, the user must leave the graphical domain and write code in the underlying implementation language. This makes it difficult for less experienced users to add new kinds of constraints. As a step toward solving this problem, the system described here allows the graphical definition of constraints. An interface has been built in which a user can conveniently construct a new kind of object, annotating it with the relations that it must obey.
A preliminary excursion into step-logics
Authors: J Drapkin, D Perlis
Venue: Proceedings of the ACM SIGART international symposium on Methodologies for intelligent systems (1986)

We have suggested that a new kind of logical study that focuses on individual deductive steps is appropriate to agents that must do commonsense reasoning. In order to adequately study such reasoners, a formal description of such &ldquo;steps&rdquo; is necessary. Here we carry further this program for the propositional case. In particular we give a result on completeness for reasoning about agents.
Correctness proofs of distributed termination algorithms
Authors: Krzysztof R. Apt
Venue: ACM Transactions on Programming Languages and Systems (TOPLAS) (1986)

The problem of correctness of the solutions to the distributed termination problem of Francez [7] is addressed. Correctness criteria are formalized in the customary framework for program correctness. A very simple proof method is proposed and applied to show correctness of a solution to the problem. It allows us to reason about liveness properties of temporal logic (see, e.g., Manna and Pnueli [12]) using a new notion of weak total correctness.
Reference identification and reference identification failures
Authors: Bradley A. Goodman
Venue: Computational Linguistics (1986)

The goal of this work is the enrichment of human-machine interactions in a natural language environment. Because a speaker and listener cannot be assured to have the same beliefs, contexts, perceptions, backgrounds, or goals at each point in a conversation, difficulties and mistakes arise when a listener interprets a speaker's utterance. These mistakes can lead to various kinds of misunderstandings between speaker and listener, including reference failures or failure to understand the speaker's intention. We call these misunderstandings miscommunication. Such mistakes can slow, and possibly break down, communication. Our goal is to recognize and isolate such miscommunications and circumvent them. This paper highlights a particular class of miscommunication - reference problems - by describing a case study and techniques for avoiding failures of reference. We want to illustrate a framework less restrictive than earlier ones by allowing a speaker leeway in forming an utterance about a task and in determining the conversational vehicle to deliver it. The paper also promotes a new view for extensional reference.
Development of APL&mdash;based distributed processing systems
Authors: Steven I. Promisel
Venue: Proceedings of the international conference on APL: APL in transition (1987)

Business users of APL generally need to maximize results while minimizing costs. Current APL technology gives the APL developer many environments to work in (mainframe, mini and micro). In addition, there are more tools available to work with in these environments. These tools include APL compilers and commercial database management systems on mainframes; full-screen input and communications utilities on microcomputers. To the end user, Distributed Processing applications combine mainframes and microcomputers into a single working environment. By programming a Distributed Processing solution in APL, the user will not need to know the details of telecommunications. The purpose of this paper is to propose questions and suggest techniques to develop Distributed Processing applications using APL.
Modes survey
Authors: Jeff Johnson, George Engelbeck
Venue: ACM SIGCHI Bulletin (1988)

A survey of the literature, informal discussions with colleagues, and a pilot version of this survey distributed among immediate colleagues suggests that though researchers and designers may give similar definitions for the concept of "modes" in interactive systems, they don't agree much on whether or not particular systems are moded. This survey is intended to determine the extent to which this is true.
Automatic verification of finite-state concurrent systems using temporal logic specifications
Authors: E. M. Clarke, E. A. Emerson, A. P. Sistla
Venue: ACM Transactions on Programming Languages and Systems (TOPLAS) (1986)

We give an efficient procedure for verifying that a finite-state concurrent system meets a specification expressed in a (propositional, branching-time) temporal logic. Our algorithm has complexity linear in both the size of the specification and the size of the global state graph for the concurrent system. We also show how this approach can be adapted to handle fairness. We argue that our technique can provide a practical alternative to manual proof construction or use of a mechanical theorem prover for verifying many finite-state concurrent systems. Experimental results show that state machines with several hundred states can be checked in a matter of seconds.
Conference grading of computer programs
Authors: Ernest Ferguson
Venue: ACM SIGCSE Bulletin (1987)

Two methods of grading computer science programs in a CSI course were evaluated in terms of (1) benefit to the student, (2) advantages for the instructor and (3) plagiarism. The two methods compared were conference grading and grading using written comments.Results indicate that students thought the grading was more fair when graded by one-on-one conference than when graded with written comments. The time required by the instructor was nearly the same. More was communicated orally in this time than in writing. There was less plagiarism in programs graded by conference, and the students whose programs had been graded by conference performed better on a programming test than those who had their programs graded by written comments. There was no significant difference between the two groups on the written examinations.