ppxscal/embedding_network huggingface dataset:
Technical aspects of the AT T Teaching Theater at the University of Maryland at College Park
Authors: Walter Gilbert
Venue: ACM SIGUCCS Newsletter (1992)

This paper describes the technological aspects of the AT amp;T Teaching Theater at the University of Maryland at College Park. These can be separated into four categories: computers, networks, audio/video, and control. All electronic equipment in the Teaching Theater is interconnected: the computers form a local-area-network which is also attached to the Campus network; the computer monitors, keyboards, and mice are interconnected via a signal-switching system; all A/V devices are connected to a video signal switcher which is connected to the computers and to the Campus video cable system; and the control system permits convenient operation of the computers, A/V, and room lighting.
Microcomputers and multi-tasking machine control
Authors: Anthony A. Kempka
Venue: ACM SIGSMALL/PC Notes (1991)

Microcomputers offer the world of machine control an unequaled tool in providing flexible control of large and complicated machines. Traditionally a microcomputer is allotted for each machine to be controlled thereby massing several microcomputers. However, factors such as economic considerations or logistics may force a designer to stretch a microcomputer beyond its traditional capabilities. A method of providing concurrent control of multiple machines using a single uni-tasking microcomputer system is investigated. The investigation is founded upon a working system designed and built for the USDA-ARS soils laboratory in Morris, Minnesota. The analysis, therefore, has a certain practical flair to it that can be found useful for other projects where multiple tasks need to be handled simultaneously.
An integrated architecture for intelligent agents
Authors: Barbara Hayes-Roth
Venue: ACM SIGART Bulletin (1991)

Our research focuses on highly sophisticated intelligent agents having three key characteristics requiring integration:* Adaptivity. An intelligent agent interacts with--influences and is influenced by--other dynamic entities in its environment. It perceives data from the environment, reasons to interpret perceptions, solve problems, make decisions, etc., acts to affect external entities and to achieve its goals. To keep pace with external events and avoid missing important demands and opportunities for action, the agent performs these functions asynchronously, concurrently, and selectively. Nonetheless, these functions must be integrated. Perception must inform reasoning and action. Reasoning must guide perception and action. Action must feed back on perception and reasoning.
APL for the USSR: perception, problems, perspective (a case of potential users)
Authors: Alexey I. Kononov
Venue: ACM SIGAPL APL Quote Quad (1991)

This article is the printed version of the report made at the annual Scientific and Practical Conference on APL, organized by the Union of Soviet APL Users for Soviet and foreign participants, which was held in April, 1991 in Leningrad, USSR. Some different aspects of APL representation in the Obninsk Post-graduate Extension School and the relation to it of a variety of specialists who studied there, are analyzed. The difficulties in APL utilization by Soviet users, their requirements, and a special view on the future of APL are shown.
Synchronization mechanisms for distributed event-driven computation
Authors: Vijay K. Madisetti, David A. Hardaker
Venue: ACM Transactions on Modeling and Computer Simulation (TOMACS) (1992)

We analyze distributed event-driven computation on message-passing parallel computing systems. Synchronization is the mechanism that ensures that causality in the ordering of stochastically generated events for execution during the computation is maintained. We characterize distributed event-driven computation into weakly coupled (weak interactions) and strongly coupled (strong interactions) distributed systems and propose and analyze a number of new algorithms for efficient synchronization. The analytical results for steady state performance are complemented with detailed simulations of the transient performance. We show that synchronization enforced separately from computation results in an efficient implementation. Effects of the memory hierarchy and communication delays are also incorporated.
Learning to Perceive and Act by Trial and Error
Authors: Steven D. Whitehead, Dana H. Ballard
Venue: Machine Learning (1991)

This article considers adaptive control architectures that integrate active sensory-motor systems with decision systems based on reinforcement learning. One unavoidable consequence of active perception is that the agent's internal representation often confounds external world states. We call this phoenomenon perceptual aliasing and show that it destabilizes existing reinforcement learning algorithms with respect to the optimal decision policy. We then describe a new decision system that overcomes these difficulties for a restricted class of decision problems. The system incorporates a perceptual subcycle within the overall decision cycle and uses a modified learning algorithm to suppress the effects of perceptual aliasing. The result is a control architecture that learns not only how to solve a task but also where to focus its visual attention in order to collect necessary sensory information.
Optimal VLSI architectures for multidimensional DFT (preliminary version)
Authors: Ginfranco Bilardi, Scot W. Hornick, Majid Sarrafzadeh
Venue: ACM SIGARCH Computer Architecture News (1991)

A family of VLSI architectures for computing an (n1 times; n2 times; hellip; times; nd)-point multidimensional DFT (MDDFT) over #8484;M, the ring of integers modulo M, is presented. These architectures achieve VLSI area A = O ((N2log2M)/T2 for any computation time T #8714; [ Omega;(logN), O ( radic;NlogM)] where N = prod;dk=1nk and it is assumed that logM = O (logN). A lower bound argument is developed to show that the proposed architectures are area-time optimal. The applicability of these architectures to computation of the MDDFT over the complex field is also discussed. Using fixed-point arithmetic with b bits of precision, their area-time performance is AT2 = O (N2b2) for any computation time T #8714; [ Omega;(logN), O( radic;Nb)].
Usability testing vs. heuristic evaluation: was there a contest?
Authors: Robin Jeffries, Heather Desurvire
Venue: ACM SIGCHI Bulletin (1992)

Recent research comparing usability assessment methods has been interpreted by some to imply that usability testing is no longer necessary, because other techniques, such as heuristic evaluation, can find some usability problems more cost-effectively. Such an interpretation grossly overstates the actual results of the studies. In this article, we, as authors of studies that compared inspection methods to usability testing, point out the rather severe limitations to using inspection methods as a substitute for usability testing and argue for a more balanced repertoire of usability assessment techniques.
The use of think-aloud evaluation methods in design
Authors: Peter C. Wright, Andrew F. Monk
Venue: ACM SIGCHI Bulletin (1991)

This paper reports on two studies in which teams of two or three trainee designers evaluated a user interface by observing a user working through some set tasks. These users were instructed to think aloud as they worked. The instruction received by the designers took the form of a brief how-to-do-it manual. Study 1 demonstrates that this method is effective. Study 2 found that more problems were detected by the designers of the system than other groups. Also, designers cannot predict the problems users will experience in advance of user testing.
Generation of Digit Reversed Address Sequences for Fast Fourier Transforms
Authors: T. C. Choinski, T. T. Tylaska
Venue: IEEE Transactions on Computers (1991)

The hardware design of a circuit capable of producing digit reversed sequences for radix-2, radix-4, and mixed radix-2/4 fast Fourier transform (FFT) algorithms is presented in detail. The design requires selectively routing the output of a binary counter to the output address pointer used during the execution of the FFT. The digit reversed counter is capable of generating address sequences for fast sequences for fast Fourier transforms varying in size from 4 to 64 K data points.
Neural nets for image restoration
Authors: A. D. Kulkarni
Venue: Proceedings of the 1990 ACM annual conference on Cooperation (1990)

No imaging system in practice is perfect, in fact the recorded images are always distorted or of finite resolution. An image recording system can be modeled by a Fredholm integral equation of the first kind. An inversion of the kernel representing the system, in the presence of noise, is an ill posed problem. The direct inversion often yields an unacceptable solution. In this paper, we suggest an Artificial Neural Network (ANN) architecture to solve ill posed problems in the presence of noise. We use two types of neuron like processing units: the units that use the weighted sum and the units that use the weighted product. The weights in the model are initialized using the eigen vectors of the kernel matrix that characterizes the recording system. We assume the solution to be a sample function of a wide sense stationary process with a known auto-correlation function. As an illustration, we consider two images that are degraded by motion blur.
Structured programming with limited private types in Ada: nesting if for the soaring eagles
Authors: Henry G. Baker
Venue: ACM SIGAda Ada Letters (1991)

Many traditional styles of programming cannot cope with the limitations of Ada limited private types. We present a style of programming that enables structured programming in Ada with limited private types. The problem of "finalization" is safely and cleanly handled through the use of a generic package which guarantees that a variable of the limited private type will be finalized even in the presence of exceptions.Finalization is often desired in order to perform automatic garbage collection, whether by reference counting or by marking. We have proved our structured technique by developing a garbage-collected Lisp system in Ada in which the Lisp values are instances of a limited private type. The Ada code was so highly structured, that it was generated automatically using a simple compiler. The garbage collector in this system was easily and safely implemented, and different garbage collection techniques were tested without affecting user code.
Lucinda&mdash;an overview
Authors: Paul Butcher, Hussein Zedan
Venue: ACM SIGPLAN Notices (1991)

This document describes the courting of Linda (a coordination language) by Russell (a computation language), and the subsequent conception of their child Lucinda. Mother and baby are both doing well.A number of disadvantages with current Linda implementations are discussed, and a new language, Lucinda, is proposed to overcome them. Lucinda provides multiple, typed tuple spaces, polymorphism, and a novel approach to data structuring and storage.
Some remarks on numerical iterations in a symbolic manipulation system
Authors: Aik-Koan Heng
Venue: Journal of Symbolic Computation (1990)

Real numbers are represented as rational numbers in a symbolic manipulation system. The advantage of using this type of system performing numerical iterations is to reduce the round-off error of operations. In fact, the roundoff error of operations is equal to zero as the calculation is exact. In this article, we will study the convergence properties of numerical iterations in this type of machine.
Multiple Resolution Segmentation of Textured Images
Authors: Charles Bouman, Bede Liu
Venue: IEEE Transactions on Pattern Analysis and Machine Intelligence (1991)

A multiple resolution algorithm is presented for segmenting images into regions with differing statistical behavior. In addition, an algorithm is developed for determining the number of statistically distinct regions in an image and estimating the parameters of those regions. Both algorithms use a causal Gaussian autoregressive model to describe the mean, variance, and spatial correlation of the image textures. Together, the algorithms can be used to perform unsupervised texture segmentation. The multiple resolution segmentation algorithm first segments images at coarse resolution and then progresses to finer resolutions until individual pixels are classified. This method results in accurate segmentations and requires significantly less computation than some previously known methods. The field containing the classification of each pixel in the image is modeled as a Markov random field. Segmentation at each resolution is then performed by maximizing the a posteriori probability of this field subject to the resolution constraint. At each resolution, the a posteriori probability is maximized by a deterministic greedy algorithm which iteratively chooses the classification of individual pixels or pixel blocks. The unsupervised parameter estimation algorithm determines both the number of textures and their parameters by minimizing a global criterion based on the AIC information criterion. Clusters corresponding to the individual textures are formed by alternately estimating the cluster parameters and repartitioning the data into those clusters. Concurrently, the number of distinct textures is estimated by combining clusters until a minimum of the criterion is reached.
Towards a shared-memory massively parallel multiprocessor
Authors: Daniel Litaize, Abdelaziz Mzoughi, Christine Rochange, Pascal Sainrat
Venue: Proceedings of the 19th annual international symposium on Computer architecture (1992)

A set of ultra high throughput (more than one Gigabits per second) serial links used as processor-memory network can lead to the starting up of a shared-memory massively parallel multiprocessor. The bandwidth of the network is far beyond values found in present shared-memory multiprocessor networks. To feed this network the memory must be serially multiported. Such a multiprocessor can actually be build with current technologies. This paper analyzes the characteristics of such a novel architecture, presents the solutions that must be considered and the practical problems associated with close of experiments. These results show then the way to effectively build this multiprocessor, taking into account main topics such as data coherency, latency time and scalability.
Integrating reaction and planning in a heterogeneous asynchronous architecture for mobile robot navigation
Authors: Erann Gat
Venue: ACM SIGART Bulletin (1991)

We present an architecture for controlling autonomous mobile robots based on control of continuous activities (processes) rather than discrete actions. We define a hierarchy of activity, and argue that different levels of activities require different sorts of computational mechanisms to control them. Many controversial issues concerning the use of persistent internal state and higher levels of abstraction can be better understood in terms of this hierarchy. Two experiments using the architecture to control mobile robots performing complex navigation tasks are described.
Arrays and pointers considered harmful
Authors: D. C. Ince
Venue: ACM SIGPLAN Notices (1992)

Formal methods of software development are becoming important topics in software engineering as evidenced by the fact that three important publications IEEE Transactions on Software Engineering, IEEE Software and IEEE Computer were recently devoted to this topic. This paper looks at the effect that current problems with formal methods might have on language design. The paper describes what a formal method of software development is, provides an example of a mathematical specification and then, by examining the problems involved in formal data refinement, puts forward the proposition that we should now regard the array and the pointer in the same way that we regarded the goto statement during the seventies.
An object-oriented specification for compiler
Authors: Pei-Chi Wu, Feng-Jian Wang
Venue: ACM SIGPLAN Notices (1992)

In this paper, we present an object-oriented approach to compiler specification. Our method treats grammar symbols as templates which instantiate nodes of parse tree for object-oriented semantic analysis. To have better classification and inheritance for semantic description, it uses restricted CFG to specify grammar rules. The semantic specification is done based on a class hierarchy generated from the restricted CFG. Besides, that a path expression is booted to describe the possible receivers of a message releases the restriction on the specification of message (value) propagations in attribute grammar methods.
A Model of Workloads and its Use in Miss-Rate Prediction for Fully Associative Caches
Authors: Jaswinder Pal Singh, Harold S. Stone, Dominique F. Thiébaut
Venue: IEEE Transactions on Computers (1992)

A mathematical model for the behavior of programs or workloads is presented and from it is extracted the miss ratio of a finite, fully associative cache (or other first-level memory) using least-recently-used replacement under those workloads. To obtain miss ratios, the function u(t, L), defined to be the number of unique lines of size L referenced before time t, is modeled. Empirical observations show that this function appears to have the form u(t, L)=(W L/sup a/t/sup b/) (d/sup log/ /sup L log t/) where W, a, b, d are constants that are related, respectively, to the working set size, locality of references to nearby addresses (spatial locality), temporal locality (locality in time not attributable to spatial locality), and interactions between spatial locality and temporal locality. The miss ratio of a finite fully associative cache can be approximated as the time derivative of u(t, L) evaluated where the function has a value equal to the size of the cache. When the miss ratios from this model are compared to measured miss ratios for a representative trace, the accuracy is high for large caches. For smaller caches, the model is close but not highly precise.
Positioning Quadric Surfaces in all Active Stereo Imaging System
Authors: Joseph H. Nurre, Ernest L. Hall
Venue: IEEE Transactions on Pattern Analysis and Machine Intelligence (1991)

The location of surfaces using stereo imaging techniques is an important area of research for robot guidance and machine inspection applications, The underlying geometry of finite focal length stereo pinhole cameras is investigated. This is the model used in both active and passive stereo imaging systems. It is shown that the points of intersecting views from the pinhole models result in conic sections. This information is used to locate quadric surfaces in the inspection space. When the projected fringe pattern is encoded to a quadric surface, the underlying intersection mapping can be used to estimate the position of the surface. Subsets of most smooth objects can be fitted to a conic section. For inspection of smooth surfaces with projection moire techniques, this fringe interpretation method would allow for correct placement of the object.
Log on education: Quick, where do the computers go?
Authors: Elliot Soloway
Venue: Communications of the ACM (1991)

History has dealt computer and information science a special role in the inevitable restructuring of the educational system in the United States. In the coming decade computing and information technology will be the backbone of the most significant change in education in over 100 years. Rather than being an adjunct to learning and teaching, technology is facilitating a fundamental re-thinking of what should be learned and how. Such changes present the Communications readership with a unique opportunity and a serious responsibility. Toward meeting this challenge, in this column I will address some key issues in education and technology. For example, this first column examines how our basic notion of what needs to be learned is changing, and how this affects the ways in which technology is used. Subsequent columns will explore topics such as &ldquo;programming's role in learning,&rdquo; &ldquo;multi-media, and nationwide, computer-based,&rdquo; testing.
Estimating subdivision depths for rational curves and surfaces
Authors: Fuhua Cheng
Venue: ACM Transactions on Graphics (TOG) (1992)

An algorithm to estimate subdivision depths for rational curves and surfaces is presented. The subdivision depth is not estimated for the given curve/surface directly. The algorithm computes a subdivision depth for the polynomial curve/surface of which the given rational curve/surface is the image under the standard perspective projection. This subdivision depth, however, guarantees the required flatness of the given curve/surface after the subdivision. This work has applications in surface rendering, surface/surface intersection, and mesh generation.
The RightPages Image-Based Electronic Library for Alerting and Browsing
Authors: Guy A. Story, Lawrence O'Gorman, David Fox, Louise Levy Schaper, H. V. Jagadish
Venue: Computer (1992)

The RightPages electronic library prototype system, which gives users full online library services, is described. The prototype takes advantage of fast hardware, multimedia workstations, and broadband networks to process scientific and technical journals for users and to offer a service that: alerts them to the arrival of new journal articles matching their interest profiles; lets them immediately examine images of pages in the alerted articles and browse through other articles in the database; and enables them to order paper copies of any articles in the database. The system runs on a local area network that connects one or more scanning stations, a centralized document database server and multiple user stations running X Windows servers. The RightPages interface runs as an X Windows application on Sun workstations or X terminals. The system's image and document processing, including noise reduction, document layout analysis, text processing, and display processing are discussed.
A Circular Binary Search
Authors: Benjamin Arazi
Venue: IEEE Transactions on Computers (1992)

In a standard binary search, the binary representation of the index of an element in an ordered linear array is recovered serially bit by bit. For an array of N elements, the index of an element is recovered, in principle, by assigning to each element one value out of log/sub 2/ N possibilities. It is shown here that by arranging 2/sup n/-1 elements in a circular array, the bits of the binary representation of the index of an element are all recovered simultaneously based n assigning to each element one value out of two possibilities. The main theoretical result shows that the parity of an integer X is trivially recovered from the parity of the Hamming weight of the binary representation of X, X+1, X+2, and X+3, whereas, on the other hand, the parity of the Hamming weight of the binary representation of an integer is consistent with modular arithmetic considerations.