ppxscal/embedding_network huggingface dataset:
An O(log n) expected rounds randomized byzantine generals protocol
Authors: Gabriel Bracha
Venue: Journal of the ACM (JACM) (1987)

Byzantine Generals protocols enable processes to broadcast messages reliably in the presence of faulty processes. These protocols are run in a system that consists of n processes, t of which are faulty. The protocols are conducted in synchronous rounds of message exchange. It is shown that, in the absence of eavesdropping, without using cryptography, for any &egr; > 0 and t = n/(3 + &egr;), there is a randomized protocol with O(log n) expected number of rounds. If cryptographic methods are allowed, then, for &egr; > 0 and t = n/(2 + &egr;), there is a randomized protocol with O(log n) expected number of rounds. This is an improvement on the lower bound of t + 1 rounds required for deterministic protocols, and on a previous result of t/log n expected number of rounds for randomized noncryptographic protocols.
A test of a common elements theory of transfer
Authors: P. G. Polson, E. Muncher, G. Engelbeck
Venue: ACM SIGCHI Bulletin (1986)

All discussions of interface design criteria emphasize the importance of consistent operating procedures both within and across applications. This paper presents a model for positive transfer and thus a theoretical definition of consistency. An experiment manipulating training orders for utility tasks was designed to evaluate the transfer model. The experimental manipulations produced large transfer effects. Quantitative predictions were derived from the Kieras and Polson (1985) theory of human-computer interaction and the transfer model and fit using regression techniques. The transfer model accounted for 88% of the variance of the 31 cell means.
On classifying recursive algorithms
Authors: L. Carl Leinbach, Alex L. Wijesinha
Venue: ACM SIGCSE Bulletin (1986)

A scheme is presented for classifying recursive problems based upon an analysis of their parameters. Several well known recursive algorithms are then classified according to this scheme. The classification is used to determine if strategies for effecting significant savings in computation time of a recursive algorithm can be developed. Such strategies and the results of applying them are also discussed.
Providing activities for students to apply data structures concepts
Authors: Janet Hartman, Carol Chrisman
Venue: ACM SIGCSE Bulletin (1987)

This paper will describe possible types of activities that can be used in a data structures course to give students experience applying the concepts being taught. It is suggested that problems be presented within a real context and in situations where there is more than one reasonable solution. Having students develop possible data structure solutions for a problem, determine appropriate criteria for comparison of the solutions, evaluate the solutions, and select a solution for a particular problem will provide them with valuable experience. In order to successfully do this, students need to have some experience using their analysis and synthesis skills to solve problems involving data structures. Many real life problems require not just one data structure but a combination of several data structures. Students will benefit from designing data structures for both simple and complex problems. They will not only have learned what each data structure is and how to manipulate it, but also when to use each particular data structure.
Data model issues for object-oriented applications
Authors: Jay Banerjee, Hong-Tai Chou, Jorge F. Garza, Won Kim, Darrell Woelk, Nat Ballou, Hyoung-Joo Kim
Venue: ACM Transactions on Information Systems (TOIS) (1987)

Presented in this paper is the data model for ORION, a prototype database system that adds persistence and sharability to objects created and manipulated in object-oriented applications. The ORION data model consolidates and modifies a number of major concepts found in many object-oriented systems, such as objects, classes, class lattice, methods, and inheritance. These concepts are reviewed and three major enhancements to the conventional object-oriented data model, namely, schema evolution, composite objects, and versions, are elaborated upon. Schema evolution is the ability to dynamically make changes to the class definitions and the structure of the class lattice. Composite objects are recursive collections of exclusive components that are treated as units of storage, retrieval, and integrity enforcement. Versions are variations of the same object that are related by the history of their derivation. These enhancements are strongly motivated by the data management requirements of the ORION applications from the domains of artificial intelligence, computer-aided design and manufacturing, and office information systems with multimedia documents.
Two algorithms for maintaining order in a list
Authors: P. Dietz, D. Sleator
Venue: Proceedings of the nineteenth annual ACM symposium on Theory of computing (1987)

The order maintenance problem is that of maintaining a list under a sequence of Insert and Delete operations, while answering Order queries (determine which of two elements comes first in the list). We give two new algorithms for this problem. The first algorithm matches the O(1) amortized time per operation of the best previously known algorithm, and is much simpler. The second algorithm permits all operations to be performed in O(1) worst-case time.
A Digital Orrery
Authors: James H. Applegate, Michael R. Douglas, Yekta Gürsel, Peter Hunter, Charles L. Seitz, Gerald J. Sussman
Venue: IEEE Transactions on Computers (1985)

We have designed and built the Orrery, a special computer for high-speed high-precision orbital mechanics computations. On the problems the Orrery was designed to solve, it achieves approximately 10 Mflops in about 1 ft3 of space while consuming 150 W of power. The specialized parallel architecture of the Orrery, which is well matched to orbital mechanics problems, is the key to obtaining such high performance. In this paper we discuss the design, construction, and programming of the Orrery.
Building a visual designer's environment
Authors: M. Graf
Venue: Proceedings of the 1987 Fall Joint Computer Conference on Exploring technology: today and tomorrow (1987)

Computer systems designers use a variety of visual representations in developing, recording and communicating their designs. This paper describes the development of a prototype visual environment for these designers, describes early results and discusses future research directions.
Issues limiting the acceptance of user interfaces using gesture input and handwriting character recognition (panel)
Authors: John Sibert, Michael G. Buffa, Hewitt D. Crane, Wolfgang Doster, James Rhyne, Jean Renaerd Ward
Venue: ACM SIGCHI Bulletin (1986)

Recently there has been increasing attention to character recognition/graphical user interfaces under the name of &ldquo;gesture input&rdquo;. This technique actually has a long history: &ldquo;sketch recognition&rdquo; interfaces of 15 or more years ago were highly praised [Applicon 73], and user interfaces using handwriting input before the wide use of text keyboards were one of the first research goals in computer science [Bledsoe 59]. The underlying character and symbol recognition technologies have been a major research area in their own right since the early 1950s [Suen 80].The last two years have seen an upsurge in the number of developments in this area, both from commercial companies attempting to exploit new character and symbol recognition technologies, [CIC 85] [Pencept 84] [Cooper 82] and from researchers starting from fundamental questions in user interactions [Buxton 86] [Wolf 86]. However, one question still remains: &ldquo;Why has this set of techniques had so little impact on user interface design practice, despite its long history and promise?&rdquo; This panel discussion should give many answers to this question.Panelists include the leading commercial developers of handwriting input products, well-known researchers in the psychological aspects of graphical user interactions, and representatives of the research community for character recognition.The issue of supporting this type of interface is very timely: recent standardization efforts such as PHIGS and GKS for graphics interactions are known to have the unfortunate side effects of excluding some of the current user interface designs using this class of technology [10].
Demand-Driven Interpretation of FP Programs on a Data-Flow Multiprocessor
Authors: Yi-Hsiu Wei, Jean-Luc Gaudiot
Venue: IEEE Transactions on Computers (1988)

Presents a demand-driven evaluation system for list-structure language systems, using the functional language FP. It enables execution in a data-driven environment. A formal approach for transforming FP programs into lazy programs, which contain the notion of demands, is used. The superset language of FP is called DFP (demand-driven FP). A demand reduction scheme is used to remove unnecessary demand propagations on DFP programs to reduce run-time overhead. The DFP programs are translated into data-flow graphs according to the graph schemata developed from the FP-DFP transformation rules. The execution characteristics of the DFP graphs are identified and the architecture supports for efficient execution are suggested. The system allows programming in FP by infinite data structures and the application of partial-function-value evaluation. Examples of these applications are used to demonstrate the transformation process, the principles of run-time interpretation, the effectiveness of the transformation, and the power of the evaluation system.
An Optimal Algorithm for Processing Distributed Star Queries
Authors: Arbee L. P. Chen, Victor O. K. Li
Venue: IEEE Transactions on Software Engineering (1985)

The problem of optimal query processing in distributed database systems was shown to be NP-hard. However, for a special type of queries called star queries, we have developed a polynomial optimal algorithm. Semijoin tactics are applied for query processing. An execution graph is introduced to represent the semijoin programs associated with the distributed processing of the queries. We then identify optimality properties of semijoin programs for star queries, and use these properties to derive the optimal semijoin program. We have shown that the optimal semijoin program can be found from serial semijoin strategies, defined as serial semijoin programs which include each semijoin associated with the query exactly once. By making certain assumptions on the file sizes and the semijoin selectivities, we can obtain the optimal semijoin program from these strategies in polynomial time. Our assumption on selectivites is consistent in the sense that we consider the selectivity of a semijoin based on the current database state, i.e., we take into consideration the reduction effects of all prior semijoins.
Queueing delays in buffered multistage interconnection networks
Authors: Christos Bouras, John Garofalakis
Venue: Proceedings of the 1987 ACM SIGMETRICS conference on Measurement and modeling of computer systems (1987)

Our work deals with the analysis of the queueing delays of buffered multistage Banyan networks of multiprocessors. We provide tight upper bounds on the mean delays of the second stage and beyond, in the case of infinite buffers. Our results are validated by simulations performed on a network simulator constructed by us. The analytic work for network stages beyond the first, provides a partial answer to open problems posed by previous research.
Proceedings of the 20th annual symposium on Simulation
Authors: Ross A. Gagliano
Venue: Annual Simulation Symposium (1987)

The Annual Simulation Symposium is a non-profit corporation formed to provide a forum for the interchange of information related to computer simulation. Its objectives are: bull;to provide a continuation of the forum for the exchange of working experiences in the field of computer simulation, to bull;permit an opportunity to survey the state-of-the-art across a broad range of applications, to bull;demonstrate the widest possible range of simulation languages, with strengths for individual problems, and to bull;furnish an opportunity for comprehensive understanding of techniques through organized question and answer periods and personal contact. It also aims to bull;provide potential users of simulation with first-hand exposure to methods, to bull;display for library perusal, the range of literature available in the field, to bull;maintain objectivity to the art of simulation, through a non-commercial meeting without obligation to any specific language or hardware, and to bull;underwrite, through grants, the advancement of the art of simulation.Membership is provided as a result of registration at the Annual Symposium. Board of Directors is elected by the membership, one Director per year for a three year term.
Microcomputer software management: a user-oriented approach
Authors: Kathie France
Venue: Proceedings of the 15th annual ACM SIGUCCS conference on User Services (1987)

Microcomputers at Eastern Wyoming College have become an everyday tool for students, faculty, support staff, and administrators. As the impact of the increased usage of microcomputers became apparent to the Computer Services staff, a Software Management Plan was implemented. The most important consideration in the development of this plan was the user.
Story driven animation
Authors: Yosuke Takashima, Hideo Shimazu, Masahiro Tomono
Venue: ACM SIGCHI Bulletin (1986)

An animation system has been developed which generates animations from stories written in natural language. The system consists of three modules: story understanding module, stage directing module and action generating module. The story understanding module extracts actions that are not explicitly described in the story and makes a scenario. The stage directing module adapts the scenario by determining the actors' positions on the stage and setting the stage. Actors are defined as 3-Dimensional articulated figures. Each component of an actor has its primitive motion method. To achieve complicated actions, primitive motions are combined. Referring to these complicated actions, the action generating module produces animated sequences from the adapted scenario. These three modules are tightly coupled with their knowledge bases. As an example, the story of the &ldquo;Hare and Tortoise&rdquo; from Aesop's Fables, written for elementary schoolchildren is used. This example proves that it is possible to produce computer animation directly from the story written in natural language, now in Japanese.
Transformations of denotational semantics in semantics directed compiler generation
Authors: Veronique Royer
Venue: ACM SIGPLAN Notices (1986)

In semantics-directed compiler generation one is faced with the problem of how to translate a source semantic definition of a programming language into on equivalent target semantics closer to an implementation. Most of the existing works solve this problem in a non constructive way : a target semantics is exhibited first and then only proved correct against the source. We try to show that target semantics can be derived from source semantics in a constructive way and so that some correctness ideas are automatically preserved. The framework is denotational semantics.
Permutations on Illiac IV-Type Networks
Authors: C. S. Raghavendra, V. K. Prasanna Kumar
Venue: IEEE Transactions on Computers (1986)

Performing permutations of data on SIMD computers efficiently is important for high-speed execution of parallel algorithms. In this correspondence we consider realizing permutations such as perfect shuffle, matrix transpose, bit-reversal, the class of bit-permute- complement (BPC), the class of Omega, and inverse Omega permutations on N = 2n processors with Illiac IV-type interconnection network, where each processor is connected to processors at distances of &plusmn; 1 and &plusmn; N. The minimum number of data transfer operations required for realizing any of these permutations on such a network is shown to be 2(N &minus; 1). We provide a general three-phase strategy for realizing permutations and derive routing algorithms for performing perfect shuffle, Omega, Inverse Omega, bit reversal, and matrix-transpose permutations in 2(N &minus; 1) steps. Our approach is quite simple, and unlike previous approaches, makes efficient use of the topology of the Illiac IV-type network to realize these permutations using the optimum number of data transfers. Our strategy is quite powerful: any permutation can be realized using this strategy in 3(N &minus; 1) steps.
Self: The power of simplicity
Authors: David Ungar, Randall B. Smith
Venue: ACM SIGPLAN Notices (1987)

Self is a new object-oriented language for exploratory programming based on a small number of simple and concrete ideas: prototypes, slots, and behavior. Prototypes combine inheritance and instantiation to provide a framework that is simpler and more flexible than most object-oriented languages. Slots unite variables and procedures into a single construct. This permits the inheritance hierarchy to take over the function of lexical scoping in conventional languages. Finally, because Self does not distinguish state from behavior, it narrows the gaps between ordinary objects, procedures, and closures. Self's simplicity and expressiveness offer new insights into object-oriented computation.
The Reliability of Voting Mechanisms
Authors: D. Barbara, H. Garcia-Molina
Venue: IEEE Transactions on Computers (1987)

In a faulty distributed system, voting is commonly used to achieve mutual exclusion among groups of isolated nodes. Each node is assigned a number of votes, and any group with a majority of votes can perform the critical operations. Vote assignments can have a significant impact on system reliability. In this paper we address the problem of selecting vote assignments in order to maximize the probability that the critical operations can be performed at a given time by some group of nodes. We suggest simple heuristics to assign votes, and show that they give good results in most cases. We also study three particular homogeneous topologies (fully connected, Ethernet, and ring networks), and derive analytical expressions for system reliability. These expressions provide useful insights into the reliability provided by voting mechanisms.
A generalized iterative construct and its semantics
Authors: Ed Anson
Venue: ACM Transactions on Programming Languages and Systems (TOPLAS) (1987)

A new programming language construct, called DOupon, subsumes Dijkstra's selective (IF) and iterative (DO) constructs. DOupon has a predicate transformer approximately equivalent in complexity to that for DO. In addition, it simplifies a wide variety of algorithms, in form as well as in discovery and proof. Several theorems are demonstrated that are useful for correctness proofs and for optimization and that are not applicable to DO or IF. The general usefulness of DOupon derives from a separation of the concerns of invariance, through iteration, from those of termination.
The Illinois resource network&mdash;linking business and government with university and federal laboratory expertise
Authors: R. A. Zollinger
Venue: Proceedings of the 1987 Fall Joint Computer Conference on Exploring technology: today and tomorrow (1987)

The Illinois Resource Network (IRN), a statewide, computerized information service, puts business, government and the public in touch with more than 6500 university faculty experts and federal research laboratory scientists. Since 1984, IRN has been used nearly 4000 times by business, government and education. In a recent telephone survey of 111 IRN business and government clients, joint-cooperative activities/projects with faculty and scientists were begun by 36 percent (40 searches) of the respondents.
A system for interactive viewing of structured documents
Authors: Ian H. Witten, Bob Bramwell
Venue: Communications of the ACM (1985)

An existing typesetting system is tied by bridging software to an existing page-presentation program to effect both hard (typeset) copy and interactive browsing. The typesetting system formats documents for a variety of output devices, and the &ldquo;browsing&rdquo; feature appears to the user as simply another output device that happens to be interactive.
Smoothing of polyhedral models
Authors: P O Fjällström
Venue: Proceedings of the second annual symposium on Computational geometry (1986)

This paper is divided in two parts of which the first describes a method to obtain solid models with free-form geometry from polyhedral models. This is achieved by replacing the edges of the original model with curved faces, i.e. sharp edges are replaced by rounds or fillets. The &ldquo;radii&rdquo; of these rounds and fillets are controlled by weight values assigned to the original edges. The value of each weight can vary in the interval from 0 to 1, which gives increased possibilities for the user to control the radius of a round or fillet without changing the topology or shape of the polyhedral model.Several of the curved faces will be non-rectangular and in the second part of the paper a method to determine surfaces to these faces is described. To do this we can either split these faces into rectangular subfaces and fit rectangular surfaces to the subfaces or use non-rectangular surfaces. I have tried the second alternative and used a scheme that is inspired by the methods presented by Gregory Charrot, (1980), (1983) and (1984). However, my method differs from theirs in some respects:Their methods are based on a convex combination of Boolean sum surfaces which interpolate position and slope along to adjacent boundaries. The Boolean sum surfaces are based on linear Taylor interpolants. Instead of Boolean sum surfaces I use convex combinations of Taylor interpolants.I have also found that linear Taylor interpolants may not always give a satisfactory shape of the interior of the surface. A considerable improvement can be obtained by using higher degree interpolants.
Matching, unification and complexity
Authors: Deepak Kapur, Paliath Narendran
Venue: ACM SIGSAM Bulletin (1987)

Pattern matching and unification are two key primitive operations used in many inference based systems including theorem provers, term rewriting systems, computer algebra systems, deductive data bases, Prolog, logic programming systems, functional language systems, systems for analysis of specifications and program synthesis, and program verification systems. In this note, we give results recently obtained in studying the complexity of matching and unification problems for first-order terms especially when some function symbols are interpreted. For further details and proofs, the reader may wish to refer to a forthcoming paper by the authors.
Some thoughts on quality issues of end-user developed systems
Authors: Maryam Alavi
Venue: Proceedings of the twenty-first annual conference on Computer personnel research (1985)

A growing number of end-users are developing their own application systems. The potential benefits of application development by end-users include: enhanced productivity of professionals and white-collar workers, creating user-friendly applications and overcoming the implementation problems by transferring the process to the end-users. In the enthusiasm to take advantage of these benefits, it is important not to overlook the costs and risks of low quality end-user developed applications. This paper focuses on quality issues of end-user created applications and makes specific recommendations for quality control.