ppxscal/embedding_network huggingface dataset:
Extending Domain Theories: Two Case Studies in Student Modeling
Authors: D. Sleeman, Haym Hirsh, Ian Ellery, In-Yung Kim
Venue: Machine Learning (1990)

By its very nature, artificial intelligence is concerned with investigating topics that are ill-defined and ill-understood. This paper describes two approaches to expanding a good but incomplete theory of a domain. The first uses the domain theory as far as possible and fills in specific gaps in the reasoning process, generalizing the suggested missing steps and adding them to the domain theory. The second takes existing operators of the domain theory and applies perturbations to form new plausible operators for the theory. The specific domain to which these techniques have been applied is high-school algebra problems. The domain theory is represented as operators corresponding to algebraic manipulations, and the problem of expanding the domain theory becomes one of discovering new algebraic operators. The general framework used is one of generate and test&mdash;generating new operators for the domain and using tests to filter out unreasonable ones. The paper compares two algorithms, INFER and MALGEN, examining their performance on actual data collected in two Scottish schools and concluding with a critical discussion of the two methods.
Managing Ada projects: the people issues
Authors: D. G. Firesmith
Venue: Proceedings of the conference on TRI-Ada '88 (1989)

In order to successfully manage the new Ada technology, the software manager must be able to: successfully interact with upper management, negotiate with and educate the contracting agency, user, and Independent Verification and Validation (IV V) personnel, and lead an often diverse group of developers using new software development methods and tools in addition to a new language. This paper points out problems and offers solutions for dealing with project politics, sociology, and psychology that often have a larger impact on the success of Ada projects than do the technical issues.
Microarchitecture choices (implementation of the VAX)
Authors: Y. M. Patt
Venue: ACM SIGMICRO Newsletter (1989)

The VAX Architecture provides hardware implementors with an opportunity or a nightmare, depending on your point of view. Such characteristics as 304 opcodes, a large number of addressing modes, a large number of supported data types, and non-regularities in the ISA semantics all provide challenges to the microarchitect. The VAX architecture was introduced in 1977 with its first microarchitecture, the VAX 11/780, a TTL MSI implementation. Since then, there have been several distinct implementations, each reflecting (1) the technology in which it was implemented, (2) the performance/cost tradeoffs it was supposed to consider, and (3) the design methodology of its implementors. This paper is a first attempt at discussing several VAX implementations from the standpoint of the choices made in the microarchitecture as driven by the context of the device technology, the performance/cost tradeoffs, and other considerations.
Automating software analysis and testing using a program transformation system
Authors: G. Kotik, L. Markosian
Venue: ACM SIGSOFT Software Engineering Notes (1989)

We describe an approach to software analysis and test generation that combines several technologies: object-oriented databases and parsers for capturing and representing software; pattern languages for writing program templates and querying and analyzing a database of software; and transformation rules for automatically generating test cases based on the analysis results, and for automatically creating program &ldquo;mutants&rdquo; to determine adequacy of coverage of the test cases. We present a program transformation system, REFINE&trade;1, that incorporates these technologies in an open environment for software analysis and test generation. Next we present concrete examples of how our approach is being applied to analysis and test generation for C software.
Implementing the Baumslag-Cannonito-Miller polycyclic quotient algorithm
Authors: Charles C. Sims
Venue: Journal of Symbolic Computation (1990)

This paper discusses the practical problems associated with developing a computerimplementation of an algorithm described by Baumslag, Cannonito, and Miller for computing polycyclic quotients of a finitely presented group. Attention is drawn to the connection with the method of Grobner bases and techniques for computing nilpotent quotients. Some experimentation with computing class-2 nilpotent quotients and metabelian polycyclic quotients is described.
Fault Tolerance in Linear Systolic Arrays Using Time Redundancy
Authors: A. Majumdar, C. S. Raghavendra, M. A. Breuer
Venue: IEEE Transactions on Computers (1990)

A linear systolic array with fault-tolerant capabilities is described. Fault tolerance is achieved by using triple time redundancy. The array is capable of undergoing reconfiguration and can operate in a gracefully degradable mode. The concept of algorithm remapping on degraded (smaller) arrays is integrated with that of graceful degradation to obtain a general fault-tolerance technique. A new technique for restructuring algorithms and executing them on a degraded array is discussed. The requisite modifications of the interconnection, switching, and control structures to achieve fault tolerance are discussed. Reliability analysis of the system is carried out, and the reliability is compared to that of nonredundant systolic arrays. Finally, the average performance of the system, with running time and throughput as performance metrics, is estimated.
Multidimensional Balanced Binary Trees
Authors: Vijay K. Vaishnavi
Venue: IEEE Transactions on Computers (1989)

A new balanced multidimensional tree structure called a k-dimensional balanced binary tree, where k is a positive integer, is presented and integrated. It is shown that the data structure can be used to manage a set of n k-dimensional data items such that access, insertion, and deletion operations can be supported in O(log n+k) time. The data structure is a multidimensional generalization of a balanced binary tree and retains much of the simplicity and efficiency of the base structure. The data structure requires O(k) single rotations for each insertion or deletion operation.
Algorithms and software: integrating theory and practice in the undergraduate computer science curriculum
Authors: Judith Wilson, Newcomb Greenleaf, Robert Trenary
Venue: ACM SIGCSE Bulletin (1989)

A theoretical trend in the development of undergraduate computer science curricula is described. While this curriculum trend can be seen as a natural evolution of a discipline, there are other reasons for it. An opposite trend can be observed that seeks to integrate theory and practice in the undergraduate curriculum. We offer general guidelines based on this second curriculum philosophy.
Performance evaluation of static and dynamic memory systems on the Cray-2
Authors: D. A. Calahan
Venue: Proceedings of the 2nd international conference on Supercomputing (1988)

A performance study is made of dynamic and static memory versions of the CRAY-2. This includes comparative kernel-level performance as well as direct measurement of memory accessing delays. A &ldquo;black-box&rdquo; memory accessing model is proposed and the results of preliminary tests on this model are given. Open questions in relating memory characteristics and code performance are reviewed.
Research for human-computer interaction at the MRC Applied Psychology Unit (lab review)
Authors: Phil Barnard
Venue: Proceedings of the SIGCHI conference on Human factors in computing systems: Empowering people (1990)

Since its formation in World War II, and under a series of distinguished directors (Craik, Bartlett, Mackworth, Broadbent, and currently, Baddeley), the APU has developed a broad base of research capability. Areas now covered are audition, vision, attention, memory, language, reasoning, motor behavior, psychophysiology, clinical and neuropsychology. Our work on human interaction with real world artifacts focuses on the preparation and comprehension of information in documents, car driving, and, of course, the use of computers. Across these areas, the APU has often played a pioneering role, not only in individual research contributions, but in helping to establish the paradigms, theory, and practice of a given field of research. The Unit is funded by the Department of Education and Science through the Medical Research Council. Our core budget is supplemented by external grants and contracts, providing in total for a research staff of around 45 and a support staff of 30. Each year we also have 10-12 graduate students and 6-15 visiting scientists.
Automatic layout of silicon-on-silicon hybrid packages
Authors: B. Preas, M. Pedram, D. Curry
Venue: Proceedings of the 26th ACM/IEEE Design Automation Conference (1989)

In modern, high speed computer systems, performance and density limits are being set more by interconnection and packaging constraints than by transistor characteristics. The most severe limitation comes from the single-chip packages that carry the VLSI circuits. Multichip, silicon-on-silicon hybrid packages can significantly improve performance by eliminating this level of packaging. A system has been developed to automatically generate hybrid layouts given a schematic description and layouts of the VLSI circuits. This paper describes the hybrid technology, the design automation system foundation, and the hybrid layout system. This layout method, in combination with the fabrication technology, produces layouts that are 5 to 8 times more dense than the same circuits implemented with single-chip packages on printed circuit boards. Simulations show that clock speeds can be increased by a factor of two.
Traditional dialogue design applied to modern user interfaces
Authors: Jakob Nielsen
Venue: Communications of the ACM (1990)

Several examples show that principles for the design of usable dialogues are just as important for modern graphical user interfaces as they are for traditional text-based interfaces.
On distributed processibility of datalog queries by decomposing databases
Authors: Guozhu Dong
Venue: ACM SIGMOD Record (1989)

We consider distributed or parallel processing of datalog queries. We address this issue by decomposing databases into a number of subdatabases such that the computation of a program on a database can be achieved by unioning its independent evaluations on the subdatabases. More specifically, we identify two kinds of distributed-processible programs according to the properties of database decomposition. (i) A program is disjoint distributive if it is distributed processible over a decomposition consisting of subdatabases with disjoint domains. A characterization of such programs is given in terms of an easily decidable syntactic property called connectivity. (ii) A program is bounded distributive if it is distributed processible over a decomposition consisting of subdatabases with a fixed size. Three interesting characterizations of such a program are presented, the first by bounded recursion, the second by equivalence to a 1-bounded-recursive program, and the third by constant parallel complexity
Tree Searched Chain Coding for Subpixel Reconstruction of Planar Curves
Authors: R. Sriraman, J. Koplowitz, S. Mohan
Venue: IEEE Transactions on Pattern Analysis and Machine Intelligence (1989)

Coding schemes for the quantization of line drawings that outperform basic chain codes are investigated. First, subpixel accuracy reconstruction is obtained by a simple linear filtering of the chain code points, which achieves a factor-of-three to-four reduction in average reconstruction distortion for smooth curves. Second, the basic chain encoding schemes are generalized to a multipath-tree-searched encoding scheme. A variation of the (M,L)-algorithm is used to maintain M contending chain code paths in storage and choose the best path from these. Over a wide variety of source curves, tree-searched chain coding results in nearly an order of magnitude reduction in average reconstruction distortion over smoother chain codes. The performance improvement for curves is obtained with only a slight increase in bit rate over basic chain codes.
Generalized B-spline surfaces of arbitrary topology
Authors: Charles Loop, T. D. DeRose
Venue: Proceedings of the 17th annual conference on Computer graphics and interactive techniques (1990)

B-spline surfaces, although widely used, are incapable of describing surfaces of arbitrary topology. It is not possible to model a general closed surface or a surface with handles as a single non-degenerate B-spline. In practice such surfaces are often needed. In this paper, we present generalizations of biquadratic and bicubic B-spline surfaces that are capable of capturing surfaces of arbitrary topology (although restrictions are placed on the connectivity of the control mesh). These results are obtained by relaxing the sufficient but not necessary smoothness constraints imposed by B-splines and through the use of an n-sided generalization of B eacute;zier surfaces called S-patches.
Verification and validation: a consultant's perspective
Authors: J. S. Carson,  II
Venue: Proceedings of the 21st conference on Winter simulation (1989)

The purpose of this paper is to look at the questions and issues regarding verification and validation of simulation models from the industrial and/or consultant's perspective. We will discuss some of the practical as well as conceptual issues involved. In addition, this paper and presentation will briefly describe several simulation projects/case studies and the verification and validation techniques used in them.
Graphinators and the duality of SIMD and MIMD
Authors: Paul Hudak, Eric Hohr
Venue: Proceedings of the 1988 ACM conference on LISP and functional programming (1988)

Combinator reduction is a well-known implementation technique for executing functional programs. In this paper we present a new method for parallel combinator reduction based on viewing combinators simply as &ldquo;graph mutators.&rdquo; We show that each combinator in Turner's standard set can be expressed using two primitive operations on a binary graph &mdash; one to alter an edge and one to insert a vertex &mdash; and four symmetric variants of them. We call these primitive operations graphinators, and present a single 7-step graphinator sequence which implements the reduction rules for all combinators in the set. This sequence allows redexes involving any of the combinators to be reduced in parallel on a SIMD machine. We have implemented a graph reducer on the Connection Machine based on these results, together with a novel execution strategy called prudent evaluation. Preliminary performance results suggest that our implementation does reasonably well, significantly better than previous efforts, but perhaps still not well enough to be practical. Nevertheless, the approach suggests a new way of thinking about program execution, and we have thoughts on how to improve our implementation.
A distributed deadlock detection algorithm for CSP-like communication
Authors: S. -T. Huang
Venue: ACM Transactions on Programming Languages and Systems (TOPLAS) (1990)

An algorithm for detecting deadlocks in distributed systems with CSP-like communication is proposed. Unlike previous work, the proposed algorithm avoids periodically sending deadlock-detecting messages by the processes and requires no local storage for the processes with size predetermined by the number of processes in the system. The algorithm is proven to have the following properties: (0) it never detects false deadlocks; (1) it has only one process in a knot report the deadlock; and (2) it detects every true deadlock in finite time.
Assembly language courses in transition
Authors: R. Rainey Little, Mark K. Smotherman
Venue: ACM SIGCSE Bulletin (1988)

Although the CS 3 course of the ACM Curriculum '78 was defined almost a decade ago, the broader perspectives that are desired for that course have not been present in many undergraduate programs. Only recently has the pivotal role of this course begun to attract the attention of computer science faculties. This development is prompted by the increasing awareness in our profession of the need to convey basic principles along with programming skills in introductory courses, and is accompanied by the increasing availability of more well-rounded textbooks. This paper describes the transition at Clemson University from a skills-oriented &ldquo;assembly language course&rdquo; to a principles-oriented &ldquo;introduction to computer systems&rdquo; course. The course that has resulted will better prepare students for subsequent studies in languages, operating systems, and applications support software.
Algorithms for solid noise synthesis
Authors: J. P. Lewis
Venue: Proceedings of the 16th annual conference on Computer graphics and interactive techniques (1989)

A solid noise is a function that defines a random value at each point in space. Solid noises have immediate and powerful applications in surface texturing, stochastic modeling, and the animation of natural phenomena.Existing solid noise synthesis algorithms are surveyed and two new algorithms are presented. The first uses Wiener interpolation to interpolate random values on a discrete lattice. The second is an efficient sparse convolution algorithm. Both algorithms are developed for model-directed synthesis, in which sampling and construction of the noise occur only at points where the noise value is required, rather than over a regularly sampled region of space. The paper attempts to present the rationale for the selection of these particular algorithms.The new algorithms have advantages of efficiency, improved control over the noise power spectrum, and the absence of artifacts. The convolution algorithm additionally allows quality to be traded for efficiency without introducing obvious deterministic effects. The algorithms are particularly suitable for applications where high-quality solid noises are required. Several sample applications in stochastic modeling and solid texturing are shown.
Implementation of rule-based technology in a shop scheduling system
Authors: D. P. Yancey, S. Peterson
Venue: Proceedings of the 21st conference on Winter simulation (1989)

FACTOR is a product which schedules and sequences activities based on discrete event simulation; recently two new software modules have been added. The Output Analysis System (OAS) module analyzes simulation output, determines performance problems, suggests solutions, and implements the solutions by changing the model. The Site Specific Tailoring (SST) module supports an in-model rulebase which can implement control logic.This paper provides an overview of the rule-based approach which was used to implement these modules and a review of their operation. The focus of this paper is to explore what expert system technology was utilized and how it was implemented for scheduling. Development issues and application examples are discussed.
APL2OS: design considerations for a nested array file system
Authors: David M. Weintraub
Venue: ACM SIGAPL APL Quote Quad (1990)

APL2OS is an External Function for the APL2 system, designed to enable APL2 applications to access operating system files (and information about these files) in a straightforward and efficient way, using the power of APL2 syntax to maximum advantage. The design goals and approaches for APL2OS are discussed, in the context of a summary of its features.
The travelling salesman problem, revisited with APL
Authors: Gérard A. Langlet
Venue: ACM SIGAPL APL Quote Quad (1990)

This paper introduces a new algorithm for the TSP and the class of n-p complete combinatory problems, which was first found empirically, with the help of APL - used as a &ldquo;tool of thought&rdquo;. Then, a demonstration was worked out, which shows that simplicity - as well as vector programming - might lead to significant progresses in some fields of optimization. Programs are short and efficient. Reprogramming in Pascal or Fortran leads to a code that proved to run indeed faster than the interpreted APL models.&hellip; but only to a certain extent. The use of parallel processors would still greatly improve the solution of the TSP. APL should also play a role in this new tendency of computer science.
Tutorial: abstraction in numerical methods
Authors: Gerald Jay Sussman, Matthew Halfant
Venue: Proceedings of the 1988 ACM conference on LISP and functional programming (1988)

We illustrate how the liberal use of high-order procedural abstractions and infinite streams helps us to express some of the vocabulary and methods of numerical analysis. We develop a software toolbox encapsulating the technique of Richardson extrapolation, and we apply these tools to the problems of numerical integration and differentiation. By separating the idea of Richardson extrapolation from its use in particular circumstances we indicate how numerical programs can be written that exhibit the structure of the ideas from which they are formed.
On continuous Homotopic one layer routing
Authors: S. Gao, M. Jerrum, M. Kaufman, K. Mehlhorn, W. Rülling
Venue: Proceedings of the fourth annual symposium on Computational geometry (1988)

We give an &Ogr;(n3&middot;log n) time and &Ogr;(n3) space algorithm for the continuous homotopic one layer routing problem. The main contribution is an extension of the sweep paradigm to a universal cover space of the plane.
Understanding Bayesian reasoning via graphical displays
Authors: W. G. Cole
Venue: ACM SIGCHI Bulletin (1989)

Bayesian reasoning, updating subjective probability in light of new information, is notoriously difficult. One factor that may contribute to this difficulty is lack of a mental model for how to combine the three key parameters in any Bayesian problem. An experiment was conducted contrasting four representations of Bayesian problems: three types of diagrams and a two by two contingency table. All four representations led to extremely good performance on a Bayesian task. This advantage also extended to a superficially dissimilar task and also persisted beyond the day of training, suggesting that graphic and tabular representation can lead to flexible and durable changes in the way people think about such problems.
Multiprocessor transitive closure algorithms
Authors: R. Agrawal, H. V. Jagadish
Venue: Proceedings of the first international symposium on Databases in parallel and distributed systems (2000)

We present parallel algorithms to compute the transitive closure of a database relation. These algorithms are applicable both on shared-memory and message-passing architectures. Experimental verification shows an almost linear speed-up with these algorithms.
Bounding the Maximum Size of a Packet Radio Network
Authors: C. G. Prohazka
Venue: IEEE Transactions on Computers (1988)

The author addresses the problem, arising in the topology design of packet radio networks (PRNs) which use time-division multiplexing and have a diameter constraint, of what is the maximum number n/sub c/(f,k) of users which can be contained in a diameter-k PRN with f time slots per frame. The author assumed that users cannot transmit and receive simultaneously and cannot transmit/receive more than one packet at a time. This assumption implies that no two channels accessed by the same user may be assigned the same time slot. It is shown that the problem of determining n/sub c/(f,k) is identical to the problem of determining the largest number of vertices which can be contained in an f-edge colorable directed graph with diameter k. Lower bounds on n/sub c/(f,k) for f/2, k=3, 4, 5, . . . are obtained by generating large graphs of this type. The graphs are constructed and colored by simple and fast procedures which are similar for different values of f and k. An extensive bibliography on the edge-coloring problem is included.