ppxscal/embedding_network huggingface dataset:
Cautious transaction schedulers with admission control
Authors: Naoki Katoh, Toshihide Ibaraki, Tiko Kameda
Venue: ACM Transactions on Database Systems (TODS) (1985)

We propose a new class of schedulers, called cautious schedulers, that grant an input request if it will not necessitate any rollback in the future. In particular, we investigate cautious WRW-schedulers that output schedules in class WRW only. Class WRW consists of all schedules that are serializable, while preserving the write-read and read-write conflict, and is the largest polynomially recognizable subclass of serializable schedules currently known. It is shown, in this paper however, that cautious WRW-scheduling is, in general, NP-complete. Therefore, we introduce a special type (type 1R) of transaction, which consists of no more than one read step (an indivisible set of read operations) followed by multiple write steps. It is shown that cautious WRW-scheduling can be performed efficiently if all transactions are of type 1R and if admission control can be exercised. Admission control rejects a transaction unless its first request is immediately grantable.
Fast algorithms for testing unsatisfiability of ground horn clauses with equations
Authors: Jean H. Gallier
Venue: Journal of Symbolic Computation (1987)

This paper presents two fast algorithms for testing the unsatisfiability of a set of ground Horn clauses with or without equational atomic formulae. If the length of the set H of Horn clauses (viewed as the string obtained by concatenating the clauses in H) is n, it is possible to design an algorithm running in time O(n log(n)). These algorithms are obtained by generalising the concept of congruence closure to ground Horn clauses. The basic idea behind these algorithms is that the congruence closure induced by a set of ground Horn clauses can be obtained by interleaving steps in which an equational congruence closure is computed, and steps in which an implicational type of closure is computed.
Towards efficient implementation of singly-implicit methods
Authors: J. C. Butcher
Venue: ACM Transactions on Mathematical Software (TOMS) (1988)

It has been observed that for problems of low dimension the transformations used in the implementation of singly-implicit Runge-Kutta methods consume an unreasonable share of the total computational costs. Two proposals for reducing these costs are presented here. The first makes use of an alternative transformation for which the combined operation counts of the transformations together with the iterations themselves are lower than for the standard implementation scheme for singly-implicit methods. The second proposal is to use a Runge-Kutta method for which the first row of the coefficient matrix is zero but which still possesses acceptable stability properties. It is hoped that by combining these two proposals increased efficiency in the implementation of Runge-Kutta methods for stiff problems can be achieved.
QUICKTALK: a Smalltalk-80 dialect for defining primitive methods
Authors: Mark B. Ballard, David Maier, Allen Wirfs-Brock
Venue: ACM SIGPLAN Notices (1986)

QUICKTALK is a dialect of Smalltalk-80 that can be compiled directly into native machine code, instead of virtual machine bytecodes. The dialect includes &ldquo;hints&rdquo; on the class of method arguments, instance variables, and class variables. We designed the dialect to describe primitive Smalltalk methods. QUICKTALK achieves improved performance over bytecodes by eliminating the interpreter loop on bytecode execution, by reducing the number of message send/returns via binding some target methods at compilation, and by eliminating redundant class checking. We identify changes to the Smalltalk-80 system and compiler to support the dialect, and give performance measurements.
Code generation for hybrid mixed mode formulation in finite element analysis
Authors: Paul S. Wang, Hui-Qian Tan, Atef F. Saleeb, Tse-Yung P. Chang
Venue: Proceedings of the fifth ACM symposium on Symbolic and algebraic computation (1986)

Recently developed techniques for the symbolic derivation of formulas and the automatic generation of code for numerical computation are applied to formulate the hybrid mixed model in finite element analysis. The hybrid mixed model is a promising approach to overcome several difficulties associated with the more traditional displacement models for the analysis of &ldquo;constrained-media&rdquo; problems. Applying the FINGER (FINite element GEneratoR) system, FORTRAN code has been generated for computing the strain-displacement coefficients and the stiffness coefficients for a sample hybrid mixed plate bending element. Attention is paid to improving the efficiency of code generated and the generality of the approach. Described is the first full-scale problem which subject the approach to stringent conditions and requirements of an actual engineering application.
Computer science in secondary schools: curriculum and teacher certification
Authors: A. J. Turner
Venue: Communications of the ACM (1985)

Computer science in secondary schools is an area of increasing interest and concern to educators as well as to computer science professionals. Each of the next two reports addresses an issue of major importance regarding computer science in secondary schools. The first report recommends computer science courses for the secondary school curriculum, and the second report recommends requirements for teacher certification in computer science.In 1983 the ACM Education Board initiated efforts to formulate recommendations for secondary school computer science. Two task forces, one for curriculum recommendations and the other for teacher certification recommendations, were established under the Education Board's Elementary and Secondary Schools Subcommittee. The work of the two task forces was also supported by the IEEE Computer Society Educational Activities Board, and the final reports from the task forces were jointly approved by the ACM and IEEE-CS boards in July 1984. Thus the reports are significan't not only for the important issues that they address, but also because they represent a joint activity between ACM and the IEEE Computer Society.The work of the two task forces is summarized in the next two reports. The full reports are available as the publication Computer Science in Secondary Schools: Curriculum and Teacher Certification, Order Number 201850, from the ACM Order Department, P.O. Box 64145, Baltimore, MD 21264.
On the modes and meaning of feedback to transaction designers
Authors: David Stemple, Subhasish Mazumdar, Tim Sheard
Venue: ACM SIGMOD Record (1987)

An analysis of database transactions in the presence of database integrity constraints can lead to several modes of feedback to transaction designers. The different kinds of feedback include tests and updates that could be added to the transaction to make it obey the integrity constraints, as well as predicates representing post-conditions guaranteed by a transaction's execution. We discuss the various modes, meanings, and uses of feedback. We also discuss methods of generating feedback from integrity constraints, transaction details and theorems constituting both generic knowledge of database systems and specific knowledge about a particular database. Our methods are based on a running system that generates tailored theories about database systems from their schemas and uses these theories to prove that transactions obey integrity constraints.
Transfer between text editors
Authors: Peter G. Polson, Susan Bovair, David Kieras
Venue: ACM SIGCHI Bulletin (1986)

This paper describes a successful test of a quantitative model that accounts for large positive transfer effects between similar screen editors, between different line editors and from line editors to a screen editor, and between text and graphic editors. The model is tested in an experiment using two very similar full-screen text-editors differing only in the structure of their editing commands, verb-noun vs noun-verb. Quantitative predictions for training time were derived from a production system model based on the Polson and Kieras (1985) model of text editing.
A Mapping Strategy for Parallel Processing
Authors: S.-Y. Lee, J. K. Aggarwal
Venue: IEEE Transactions on Computers (1987)

This paper presents a mapping strategy for parallel processing using an accurate characterization of the communication overhead. A set of objective functions is formulated to evaluate the optimality of mapping a problem graph onto a system graph. One of them is especially suitable for real-time applications of parallel processing. These objective functions are different from the conventional objective functions in that the edges in the problem graph are weighted and the actual distance rather than the nominal distance for the edges in the system graph is employed. This facilitates a more accurate quantification of the communication overhead. An efficient mapping scheme has been developed for the objective functions, where two levels of assignment optimization procedures are employed: initial assignment and pairwise exchange. The mapping scheme has been tested using the hypercube as a system graph.
A statistical analysis of the effect of discrete mathematics on the performance of computer science majors in beginning computing classes
Authors: James R. Sidbury
Venue: Proceedings of the seventeenth SIGCSE technical symposium on Computer science education (1986)

During the 1983-84 academic year, the University of Scranton instituted an experimental two semester discrete mathematics course for freshman students majoring in computer science. Approximately one-third of them were enrolled in this sequence while the remaining freshmen were enrolled in a traditional algebra-calculus mathematics sequence. At the end of the academic year the records of the freshman computer science majors were examined to see if there was any difference in performance between those who took discrete mathematics and those who did not. There is a strong indication that students who take discrete mathematics make higher grades in computer science than do the students who take the algebra-calculus sequence of courses. There is no indication that students who take discrete mathematics are more (or less) likely to change majors during the freshman year than those who take a traditional mathematics course.
A comparative feature-analysis of microcomputer prolog implementations
Authors: J Weeks, H Berghel
Venue: ACM SIGPLAN Notices (1986)

In recent years, no programming language has received the international attention of PROLOG. Currently the Japanese Fifth Generation computing Systems Project (ICOT) is attempting to build an entire series of computers around this language in order to implement a new generation of computers based on symbolic inferencing techniques. In the United States and Europe, PROLOG is being used in relational database applications, natural language processing, theorem proving and automated reasoning, and a variety of other artificial intelligence applications.In this article, we compare several of the newer PROLOG interpreters and compilers with regard to their functionality. This information is useful to researchers in selecting the product which will be the most relevant to their applications.
On implementing Buchberger's algorithm for Grobner bases
Authors: S. R. Czapor, K. O. Geddes
Venue: Proceedings of the fifth ACM symposium on Symbolic and algebraic computation (1986)

An implementation in the Maple system of Buchberger's algorithm for computing Gr&ouml;bner bases is described. The efficiency of the algorithm is significantly affected by choices of polynomial representations, by the use of criteria, and by the type of coefficient arithmetic used for polynomial reductions. The improvement possible through a slightly modified application of the criteria is demonstrated by presenting time and space statistics for some sample problems. A fraction-free method for polynomial reduction is presented. Timings on problems with integer and polynomial coefficients show that a fraction-free approach is recommended.
Timing Issues in the Distributed Execution of Ada Programs
Authors: R. A. Volz, T. N. Mudge
Venue: IEEE Transactions on Computers (1987)

This paper examines, in the context of distributed execution, the meaning of Ada constructs involving time. In the process, unresolved questions of interpretation and problems with the implementation of a consistent notion of time across a network are uncovered. It is observed that there are two Ada mechanisms that can involve a distributed sense of time: the conditional entry call, and the timed entry call. It is shown that a recent interpretation by the Language Maintenance Committee resolves the questions for the conditional entry calls but results in an anomaly for timed entry calls. A detailed discussion of alternative implementations for the timed entry call is made, and it is argued that: 1) timed entry calls imply a common sense of time between the machines holding the calling and called tasks; and 2) the measurement of time for the expiration of the delay and the decision of whether or not to perform the rendezvous should be made on the machine holding the called task. The need to distinguish the unreadiness of the called task from timeouts caused by network failure is pointed out. Finally, techniques for realizing a single sense of time across the distributed system (at least to within an acceptable degree of uncertainty) are also discussed.
A paperless environment for group effort in documentation development
Authors: John A Cross
Venue: Proceedings of the 4th annual international conference on Systems documentation (1986)

Research into the effect of word processing on writing and a paperless environment for the submission and grading of student assignments has led to considerations for new technology to support the development of system documentation. We assert that a relatively paperless system which integrates the concepts of word processing, electronic mail, computer conferencing and the HANDIN paperless system for student assignments (Cross and Wolfe, 1985) has potential for facilitating the process of developing system documentation. A conceptual framework and specific system features are presented. Research goals and methodologies are briefly considered.
A Method for Equijoin Queries in Distributed Relational Databases
Authors: To-Yat Cheung
Venue: IEEE Transactions on Computers (1982)

A simple and efficient method for processing general equijoin queries in a distributed relational database is described. The query is first decomposed into a set of simple queries, each being involved with only one of the joining domains and its relevant equijoins. An extended version of Hevner and Yao's STRATEGY PARALLEL or STRATEGY SERIAL is then applied on each of them for generating transmission schedules. These schedules will fully reduce (with respect to a simple query) some specified relations. The latter are then transmitted to the result site for final processing. In the case of minimizing total time, our method has a lower order of complexity than ALGORITHM GENERAL studied by Hevner and Apers. Examples show that our method gives better and more efficient solutions than theirs.
Parameterized programming in OBJ2
Authors: K. Futatsugi, J. Goguen, J. Meseguer, K. Okada
Venue: Proceedings of the 9th international conference on Software Engineering (1987)

Parameterized programming [9] is a powerful technique for the construction, maintenance, and reuse of software. In this technique, modules may be parameterized over very general interfaces that describe what properties of an environment are required for the module to work correctly. Ease of construction, maintenance, and reuse of software are all enhanced by the flexibility of the parameterization mechanism provided.OBJ2 [8] is designed to support parameterized programming, using algebraic specification techniques [2, 16, 17]; it provides facilities for user-definable abstract data types, parameterized
The memory extender personal filing system
Authors: W. P. Jones
Venue: Proceedings of the SIGCHI conference on Human factors in computing systems (1986)

The benefits of electronic information storage are enormous and largely unrealized. As its cost continues to decline, the number of files in the average user's personal database may increase substantially. How is a user to keep track of several thousand, perhaps several hundred thousand, files? The Memory Extender (ME) system improves the user interface to a personal database by actively modeling the user's own memory for files and for the context in which these files are used. Files are multiply indexed through a network of variably weighted term links. Context is similarly represented and is used to minimize the user input necessary to disambiguate a file. Files are retrieved from the context through a spreading-activation-like process. The system aims towards an ideal in which the computer provides a natural extension to the user's own memory.
Improving the software process
Authors: W. E. Riddle
Venue: Proceedings of the 9th international conference on Software Engineering (1987)

Needs and possibilities for software processes are constantly changing, and improvement is therefore a continual process. Part of the task of software process improvement is the comparative evaluation of alternatives with the intent of deciding whether to shift to a new process or keep/adjust an existing one. An equally important task is to constantly increase the flexibility to adapt a software process to meet new project-related or organizational needs or utilize new technology.The intent of this panel is to expose, compare and contrast a variety of strategies and tactics for improving the software process. The assumption is that no single strategy or set of tactics will ever be best in all situations. To set the stage, the strategy and tactics discussed in the paper &ldquo;Tailoring the Software Process to Project Goals and Environments,&rdquo; by Basili and Rombach, will be presented. The panelists, each of whom has a direct responsibility for software technology improvement, will then briefly present the approaches they are using to guide software process improvement. The ensuing discussion is intended to uncover critical differences and similarities and lead to an understanding of the contexts in which the various approaches can succeed.
Self-adjusting binary search trees
Authors: Daniel Dominic Sleator, Robert Endre Tarjan
Venue: Journal of the ACM (JACM) (1985)

The splay tree, a self-adjusting form of binary search tree, is developed and analyzed. The binary search tree is a data structure for representing tables and lists so that accessing, inserting, and deleting items is easy. On an n-node splay tree, all the standard search tree operations have an amortized time bound of O(log n) per operation, where by &ldquo;amortized time&rdquo; is meant the time per operation averaged over a worst-case sequence of operations. Thus splay trees are as efficient as balanced trees when total running time is the measure of interest. In addition, for sufficiently long access sequences, splay trees are as efficient, to within a constant factor, as static optimum search trees. The efficiency of splay trees comes not from an explicit structural constraint, as with balanced trees, but from applying a simple restructuring heuristic, called splaying, whenever the tree is accessed. Extensions of splaying give simplified forms of two other data structures: lexicographic or multidimensional search trees and link/cut trees.
Efficient plane sweeping in parallel
Authors: M J Atallah, M T Goodrich
Venue: Proceedings of the second annual symposium on Computational geometry (1986)

We present techniques which result in improved parallel algorithms for a number of problems whose efficient sequential algorithms use the plane-sweeping paradigm. The problems for which we give improved algorithms include intersection detection, trapezoidal decomposition, triangulation, and planar point location. Our technique can be used to improve on the previous time bound while keeping the space and processor bounds the same, or improve on the previous space bound while keeping the time and processor bounds the same. We also give efficient parallel algorithms for visibility from a point, 3-dimensional maxima, multiple range-counting, and rectilinear segment intersection counting. We never use the AKS sorting network in any of our algorithms.
An efficient algorithm for the &ldquo;optimal&rdquo; stable marriage
Authors: Robert W. Irving, Paul Leather, Dan Gusfield
Venue: Journal of the ACM (JACM) (1987)

In an instance of size n of the stable marriage problem, each of n men and n women ranks the members of the opposite sex in order of preference. A stable matching is a complete matching of men and women such that no man and woman who are not partners both prefer each other to their actual partners under the matching. It is well known [2] that at least one stable matching exists for every stable marriage instance. However, the classical Gale-Shapley algorithm produces a marriage that greatly favors the men at the expense of the women, or vice versa. The problem arises of finding a stable matching that is optimal under some more equitable or egalitarian criterion of optimality. This problem was posed by Knuth [6] and has remained unsolved for some time. Here, the objective of maximizing the average (or, equivalently, the total) &ldquo;satisfaction&rdquo; of all people is used. This objective is achieved when a person's satisfaction is measured by the position of his/her partner in his/her preference list. By exploiting the structure of the set of all stable matchings, and using graph-theoretic methods, an O(n4) algorithm for this problem is derived.
A dynamic cluster maintenance system for information retrieval
Authors: F. Can, E. Ozkarahan
Venue: Proceedings of the 10th annual international ACM SIGIR conference on Research and development in information retrieval (1987)

Partitioning by clustering of very large databases is a necessity to reduce the space/time complexity of retrieval operations. However, the contemporary and modern retrieval environments demand dynamic maintenance of clusters. A new cluster maintenance strategy is proposed and its similarity/stability characteristics, cost analysis, and retrieval behavior in comparison with unclustered and completely reclustered database environments have been examined by means of a series of experiments.
Contemporary trends in computing
Authors: Richard M. Plishka
Venue: Proceedings of the seventeenth SIGCSE technical symposium on Computer science education (1986)

Many computer science curricula use Special Topics courses as a vehicle to introduce students to new concepts and technologies. Although the same policy is practiced at our institution, one course required of our Associate Degree students provides a forum for surveying contemporary trends in computing. Such a course is essential for providing &ldquo;a foundation of knowledge and skills sufficient to serve as a base for continued learning.&rdquo; [1] The purpose and content of this course is the topic that follows.
The partial metrics system: modeling the stepwise refinement process using partial metrics
Authors: Robert G. Reynolds
Venue: Communications of the ACM (1987)

The Partial Metrics System design is explained, with an emphasis on the refinement process. A model, with its three phases, shows that the pseudocode refinement process can be monitored in partial metric terms.