ppxscal/embedding_network huggingface dataset:
Reduced distance routing in single-state shuffle-exchange interconnection networks
Authors: Ziao-Nan Tan, Kenneth C. Sevcik
Venue: Proceedings of the 1987 ACM SIGMETRICS conference on Measurement and modeling of computer systems (1987)

In multiprocessor architectures, it is frequently necessary to provide parallel communication among a potentially large number of processors and memories. Among the many interconnection schemes that have been proposed and analyzed, shuffle-exchange networks have received much attention due to their ability to allow a message to pass from any node to any other node in a number of steps that grows only logarithmically with the number of interconnected nodes (in the absence of contention) while keeping the number of hardware connections per node independent of the number of nodes. Straight-forward use of shuffle-exchange networks to interconnect &Ngr; nodes involves having every packet pass through log2 &Ngr; stages enroute to its destination. By exploiting common structure in the addresses of the source and destination nodes, however, more sophisticated routing can reduce the average number of steps per message below log2 &Ngr;. In this paper, we describe and evaluate three levels of improvements to basic single-stage shuffle-exchange routing. Each one yields successively more benefit at the cost of more complexity. Using simulation, we show that the use of routing schemes that reduce the average distance can substantially reduce average message delay times and increase interconnection network capacity. We quantify the performance gains only in the case where messages from one node are destined with uniform probability over all nodes. However, it is clear that the advantage of the new schemes we propose would be still greater if there is some &ldquo;locality&rdquo; of communication that can be exploited by having the most frequent communication occur between pairs of nodes with shorter distances separating them.
Comments on "Direct Implementation of Discrete and Residue-Based Functions Via Optimal Encoding: A Programmable Array Logic Approach"
Authors: M M Mirsalehi, T K Gaylord
Venue: IEEE Transactions on Computers (1986)

An analytic expression for the lower bound on the complexity of residue multiplication is developed. Significant reduction of the required stored logic in a content-addressable memory is noted. Errors in Figs. 5(a), 7, and 8 of the above paper1 are corrected.
A Recursion Theoretic Approach to Program Testing
Authors: J. C. Cherniavsky, C. H. Smith
Venue: IEEE Transactions on Software Engineering (1987)

Inductive inference, the automatic synthesis of programs, bears certain ostensible relationships with program testing. For inductive inference, one must take a finite sample of the desired input/output behavior of some program and produce (synthesize) an equivalent program. In the testing paradigm, one seeks a finite sample for a function such that any program (in a given set) which computes something other than the object function differs from the object function on the finite sample. In both cases, the finite sample embodies sufficient knowledge to isolate the desired program from all other possibilities. These relationships are investigated and general recursion theoretic properties of testable sets of functions are exposed.
Condensed Linear Feedback Shift Register (LFSR) Testing A Pseudoexhaustive Test Technique
Authors: Laung-Terng Wang, Edward J. McCluskey
Venue: IEEE Transactions on Computers (1986)

This paper presents a design technique for linear feedback shift registers that generate test patterns for pseudoexhaustive testing. This technique is applicable to any combinational network in which none of the outputs depends on all inputs. It does not rewire the original network inputs during in-circuit test pattern generation. Thus, the possibility of undetected faults on some inputs is eliminated.
Graphic displays of data structures on the IBM PC
Authors: Moshe Augenstein, Yedidyah Langsam
Venue: Proceedings of the seventeenth SIGCSE technical symposium on Computer science education (1986)

Immediately or soon after an introductory course in programming, traditional computer science education usually includes a course on data structures. Such courses, however, have suffered from a lack of non-textual materials for classroom and non-classroom use. Consequently, it is difficult for students to comprehend the abstractions involved in implementing and applying fundamental data structures without laboriously employing printed materials. The work discussed herein addresses the problem by developing software for the IBM PC that will allow data structure users to view graphically the effects of primitive operations and application programs on basic data structures. Several such structures and applications are examined and plans for a program interface are discussed.
On the power series solution of a system of algebraic equations
Authors: S. Moritsugu
Venue: ACM SIGSAM Bulletin (1987)

This paper discusses the power series solution of a system of algebraic equations which is computed by the multivariate symbolic Newton's method. Applying Newton's method naively, we obtain a power series solution the coefficients of which are large rational function of the initial approximation. An algorithm is given to reduce the solution to the normal form by using Gr ouml;bner basis method.
The design and implementation of distributed Smalltalk
Authors: John K. Bennett
Venue: ACM SIGPLAN Notices (1987)

Distributed Smalltalk (DS) is an implementation of Smalltalk that allows objects on different machines to send and respond to messages. It also provides some capability for sharing objects among users. The distributed aspects of the system are largely user transparent and preserve the reactive quality of Smalltalk objects. Distributed Smalltalk is currently operational on a network of Sun workstations. The implementation includes an incremental distributed garbage collector and support for remote debugging, access control, and object mobility. This paper concentrates on the important design issues encountered and some of the more interesting implementation details. Performance measurements of the current implementation are included.
Closures of database hypergraphs
Authors: Domenico Saccà
Venue: Journal of the ACM (JACM) (1985)

A hypergraph formalism is introduced to represent database schemata. In particular, a database schema B, described by one full join dependency and a set of functional dependencies, is represented by a (database) hypergraph H, containing both undirected and directed hyperedges. Undirected hyperedges correspond to the relations in the join dependency, and directed hyperedges correspond to the functional dependencies. In addition, two classes of database hypergraphs are defined: e-acyclic hypergraphs and e-independent hypergraphs. A hypergraph is e-acyclic if it is equivalent to some acyclic hypergraph; it is e-independent if it is equivalent to some independent (i.e., cover-embedding) hypergraph. Furthermore, the closure of a database hypergraph is defined as the extension of the transitive closure of a graph. By using a lower bound and an upper bound of the hypergraph closure (called L-closure and U-closure, respectively), it is proved that two e-acyclic (e-independent) hypergraphs are equivalent if and only if they have the same closure. Moreover, a hypergraph is e-acyclic (e-independent) if and only if its closure is acyclic (independent) and, in most cases, such a recognition can be done in polynomial time. Finally, it is shown how to use the database hypergraph closure to solve some database design problems.
BAROQUE: a browser for relational databases
Authors: Amihai Motro
Venue: ACM Transactions on Information Systems (TOIS) (1986)

The standard, most efficient method to retrieve information from databases can be described as systematic retrieval: The needs of the user are described in a formal query, and the database management system retrieves the data promptly. There are several situations, however, in which systematic retrieval is difficult or even impossible. In such situations exploratory search (browsing) is a helpful alternative. This paper describes a new user interface, called BAROQUE, that implements exploratory searches in relational databases. BAROQUE requires few formal skills from its users. It does not assume knowledge of the principles of the relational data model or familiarity with the organization of the particular database being accessed. It is especially helpful when retrieval targets are vague or cannot be specified satisfactorily. BAROQUE establishes a view of the relational database that resembles a semantic network, and provides several intuitive functions for scanning it. The network integrates both schema and data, and supports access by value. BAROQUE can be implemented on top of any basic relational database management system but can be modified to take advantage of additional capabilities and enhancements often present in relational systems.
Steps to an Advanced Ada1Programming Environment
Authors: Richard N. Taylor, Thomas A. Standish
Venue: IEEE Transactions on Software Engineering (1985)

Conceptual simplicity, tight coupling of tools, and effective support of host-target software development will characterize advanced Ada programming support environments. Several important principles have been demonstrated in the Arcturus system, including template-assisted Ada editing, command completion using Ada as a command language, and combining the advantages of interpretation and compilation. Other principles, relating to analysis, testing, and debugging of concurrent Ada programs, have appeared in other contexts. This paper discusses several of these topics, considers how they can be integrated, and argues for their inclusion in an environment appropriate for software development in the late 1980's.
A knowledge-based approach to multiple query processing in distributed database system
Authors: J. T. Park, T. J. Teorey
Venue: Proceedings of the 1987 Fall Joint Computer Conference on Exploring technology: today and tomorrow (1987)

The collective processing of multiple queries in a database system has recently received renewed attention due to its capability of improving the overall performance of a database system and its applicability to the design of knowledge-based expert systems and extensible database systems. A new multiple query processing strategy is presented which utilizes semantic knowledge on data integrity and information on predicate conditions of the access paths (plans) of queries. The processing of multiple queries is accomplished by the utilization of subset relationships between intermediate results of query executions, which is inferred employing both semantic knowledge and logical information. Given a set of fixed order access plans, the A* algorithm is used to find the set of reformulated access plans which is optimal for a given collection of semantic knowledge.
Burnside's theorem
Authors: D. Binger
Venue: ACM SIGSAM Bulletin (1987)

This project was derived directly from Eva Gray's translation of project No. 001-001, Satz von Burnside, by E. Graf from ETH.
Structured Highlight Inspection of Specular Surfaces
Authors: A. C. Sanderson, L. E. Weiss, S. K. Nyar
Venue: IEEE Transactions on Pattern Analysis and Machine Intelligence (1988)

An approach to illumination and imaging of specular surfaces that yields three-dimensional shape information is described. The structured highlight approach uses a scanned array of point sources and images of the resulting reflected highlights to compute local surface height and orientation. A prototype structured highlight inspection system, called SHINY, has been implemented. SHINY demonstrates the determination of surface shape for several test objects including solder joints. The current SHINY system makes the distant-source assumption and requires only one camera. A stereo structured highlight system using two cameras is proposed to determine surface-element orientation for objects in a much larger field of view. Analysis and description of the algorithms are included. The proposed structured highlight techniques are promising for many industrial tasks.
The partition model: a deductive database model
Authors: Nicolas Spyratos
Venue: ACM Transactions on Database Systems (TODS) (1987)

We present a new database model in which each attribute is modeled by a family of disjoint subsets of an underlying population of objects. Such a family is called a partitioning, and the set of all partitionings is turned into a lattice by appropriately defining product and sum. A database is seen as a function from a sublattice into the lattice of partitionings. The model combines the following features: (1) syntactic simplicity (essentially that of the relational model), (2) powerful means for the specification of semantic information (in the form of lattice equations), and (3) deductive capability (essentially that of set theory). The relational model of data and the basic constructs of semantic modeling can be embedded into our model in a simple and straightforward manner.
Biographies
Authors: Eric Weiss
Venue: IEEE Annals of the History of Computing (1988)

No abstract available.
Real time design and animation of fractal plants and trees
Authors: Peter E. Oppenheimer
Venue: ACM SIGGRAPH Computer Graphics (1986)

The goal of science is to understand why things are the way they are. By emulating the logic of nature, computer simulation programs capture the essence of natural objects, thereby serving as a tool of science. When these programs express this essence visually, they serve as an instrument of art as well.This paper presents a fractal computer model of branching objects. This program generates pictures of simple orderly plants, complex gnarled trees, leaves, vein systems, as well as inorganic structures such as river deltas, snow flakes, etc. The geometry and topology of the model are controlled by numerical parameters which are analogous to the organism's DNA. By manipulating the genetic parameters, one can modify the geometry of the object in real time, using tree based graphics hardware. The random effects of the environment are taken into account, to produce greater diversity and realism. Increasing the number of significant parameters yields more complex and evolved species.The program provides a study in the structure of branching objects that is both scientific and artistic. The results suggest that organisms and computers deal with complexity in similar ways.
The BANG file: A new kind of grid file
Authors: Michael Freeston
Venue: ACM SIGMOD Record (1987)

A new multi-dimensional file structure has been developed in the course of a project to devise ways of improving the support for interactive queries to database and knowledge bases. Christened the 'BANG' file - a Balanced And Nested Grid - the new structure is of the 'grid file' type, but is fundamentally different from previous grid file designs in that it does not share their common underlying properties. It has a tree-structured directory which has the self-balancing property of a B-tree and which, in contrast to previous designs, always expands at the same rate as the data, whatever the form of the data distribution. Its partitioning strategy both accurately reflects the clustering of points in the data space, and is flexible enough to adapt gracefully to changes in the distribution.
A shading model for atmospheric scattering considering luminous intensity distribution of light sources
Authors: Tomoyuki Nishita, Yasuhiro Miyawaki, Eihachiro Nakamae
Venue: Proceedings of the 14th annual conference on Computer graphics and interactive techniques (1987)

Studio spotlights produce dazzling shafts of light, while light scattered from fog illuminated by automobile headlights renders driving difficult. This is because the particles in the illuminated volume become visible by scattering light. A shading model for scattering and absorption of light caused by particles in the atmosphere is proposed in this paper. The method takes into account luminous intensity distribution of light sources, shadows due to obstacles, and density of particles. The intensity at a viewpoint is calculated by integration of light scattered by particles between the viewpoint and a given point on an object. The regions to be treated in this manner are localized by considering illumination volumes and shadow volumes caused by obstacles in the illumination volumes.
An Intrusion-Detection Model
Authors: Dorothy E. Denning
Venue: IEEE Transactions on Software Engineering (1987)

A model of a real-time intrusion-detection expert system capable of detecting break-ins, penetrations, and other forms of computer abuse is described. The model is based on the hypothesis that security violations can be detected by monitoring a system's audit records for abnormal patterns of system usage. The model includes profiles for representing the behavior of subjects with respect to objects in terms of metrics and statistical models, and rules for acquiring knowledge about this behavior from audit records and for detecting anomalous behavior. The model is independent of any particular system, application environment, system vulnerability, or type of intrusion, thereby providing a framework for a general-purpose intrusion-detection expert system.
Checkpointing and Rollback-Recovery for Distributed Systems
Authors: Richard Koo Sam Toueg
Venue: IEEE Transactions on Software Engineering (1987)

We consider the problem of bringing a distributed system to a consistent state after transient failures. We address the two components of this problem by describing a distributed algorithm to create consistent checkpoints, as well as a rollback-recovery algorithm to recover the system to a consistent state. In contrast to previous algorithms, they tolerate failures that occur during their executions. Furthermore, when a process takes a checkpoint, a minimal number of additional processes are forced to take checkpoints. Similarly, when a process rolls back and restarts after a failure, a minimal number of additional processes are forced to roll back with it. Our algorithms require each process to store at most two checkpoints in stable storage. This storage requirement is shown to be minimal under general assumptions.
Socrates: a project integrating human science with computer science
Authors: Carl M. Vogel
Venue: Issue 105 (July 1988) (1988)

This paper regards a project whose design objective was a synthesis of two perspectives on the use of computers in education. Computers may be used to educate, and people may be educated to use computers. Socrates is a project in the area of expert systems development. It was designed to be a workable tool in the field of abnormal psychology, but the educational setting was prominent during the design process. The tool chosen for development was a diagnostic expert system capable of producing a valid, reliable diagnosis on Axes I and III of the American Psychiatric Association's Diagnostic and Statistical Manual, Third Edition (DSM-III) of alcohol-use related maladaptive behavior patterns. The development of Socrates was approached using some of the perspectives that software engineers bring to the development of complex software systems. However, using algorithmic tools to solve a problem that is answerable only through heuristics renders those tools less useful. The system, implemented in PROLOG, was constructed from complex functional representations of data. Data flow diagrams (DFDs) tended to distort the exact picture of the system's functioning. If we simply rename the tool "Logical Instantiation Diagram" (LID), the psychological limitations of DFD's are eliminated since there is no longer any demand to adhere to DFD convention. Naturally, a project of this complexity involves the programmers very deeply in the implementation environment. PROLOG was studied as an applicative programming language, and yet it was discovered that it is possible to force procedurality onto PROLOG. The bridge between learning about expert system development and integrating the domain of a particular system is knowledge engineering. Here the emphasis is not on specialized programming techniques, but on the programmer's ability to reason inside the problem domain and to communicate that reasoning through the language at hand, be it LFD's actual PROLOG code, or the code of some other computer language. The knowledge engineer will come to recognize ways of thinking that are perhaps not included in a traditional programming discipline. Socrates is more than a project in expert system design; it is a study of learning. The project progressed from difficulties in representing ambiguous situations unambiguously to the recognition that the chief domain document is flawed inherently, as is any system which applies a finite number of classifications to an infinite number of possibilities. We propose Socrates as a model of liberal arts education. As a study of knowledge engineering it unites two distinct disciplines in a program of joint discovery. In working on Socrates we were able to develop specific ideas about the nature of our implementation, we made observations about the environment in which we were working, and finally, we were able to generalize the tools used in other areas of software development adapting them effectively to our own uses.
The information economy: A new perspective for effective information systems management
Authors: Robert W Zmud, Andrew C Boynton, Gerry C Jacobs
Venue: ACM SIGMIS Database (1986)

"The basic function of administration appears to be co-alignment, not merely of people in coalitions but of institutionalized action --- of technology and task environment into a viable domain, and of organizational design and structure appropriate to it. Administration, when it works well, keeps the organization at the nexus of several necessary streams of action" [13].
The impact of robotics on computer science
Authors: John E. Hopcroft
Venue: Communications of the ACM (1986)

The rapid development of robotics and the resulting need for computer scientists to be better trained in traditional mathematics necessitate changes in computer science curricula.
Correct memory operation of cache-based multiprocessors
Authors: C. Scheurich, M. Dubois
Venue: Proceedings of the 14th annual international symposium on Computer architecture (1987)

This paper shows that cache coherence protocols can implement indivisible synchronization primitives reliably and can also enforce sequential consistency. Sequential consistency provides a commonly accepted model of behavior of multiprocessors. We derive a simple set of conditions needed to enforce sequential consistency in multiprocessors. These conditions are easily applied to prove the correctness of existing cache coherence protocols that rely on one or multiple broadcast buses to enforce atomicity of updates; in these protocols, all processing elements must be connected to the broadcast buses. The conditions are also used in this paper to establish new protocols which do not rely on the atomicity of updates and therefore do not require single access buses to propagate invalidations or to perform distributed WRITEs. It is also shown how such protocols can implement atomic READ MODIFY operations for synchronization purposes.