ppxscal/embedding_network huggingface dataset:
PDP-11 simulator for Apple Macintosh is designed for instructional use
Authors: Roy Fuller
Venue: ACM SIGCSE Bulletin (1991)

We describe a interactive PDP-11 simulator that runs on the Apple Macintosh. The simulator has been extremely easy for students at the University of Arkansas to learn and operate after a fraction of one lecture period of explanation. It has been utilized for three years in two undergraduate courses: computer organization and assemblers, translators amp; compilers. Compared to using an actual PDP-11 or a simulator (not the author's) running on our University's mainframe, we have found that the students using the Macintosh simulator achieve higher productivity, measured not by the number of lines assembled or executed in a second but by the number of human hours spent writing and debugging a program. Students gain a clearer understanding of concepts that are intrinsically dynamic (such as the birth and death of activation records) due to the ease with which (simulated) memory and registers can be monitored during execution.
A data path layout assembler for high performance DSP circuits
Authors: H. Cai, S. Note, P. Six, H. De Man
Venue: Proceedings of the 27th ACM/IEEE Design Automation Conference (1991)

A system is presented which automatically generates layout of bit-sliced data paths in high performance DSP circuits. The system consists of a linear placement tool, a track assignment tool and detailed layout tools. In this paper we will present algorithms for linear placement of modules and routing track assignment across the modules. By taking advantage of the inherent structure of the circuits an A* based linear placement algorithm has produced better results compared to a simulated annealing based approach.
Compiler support for garbage collection in a statically typed language
Authors: Amer Diwan, Eliot Moss, Richard Hudson
Venue: ACM SIGPLAN Notices (1992)

We consider the problem of supporting compacting garbage collection in the presence of modern compiler optimizations. Since our collector may move any heap object, it must accurately locate, follow, and update all pointers and values derived from pointers. To assist the collector, we extend the compiler to emit tables describing live pointers, and values derived from pointers, at each program location where collection may occur. Significant results include identification of a number of problems posed by optimizations, solutions to those problems, a working compiler, and experimental data concerning table sizes, table compression, and time overhead of decoding tables during collection. While gc support can affect the code produced, our sample programs show no significant changes, the table sizes are a modest fraction of the size of the optimized code, and stack tracing is a small fraction of total gc time. Since the compiler enhancements are also modest, we conclude that the approach is practical.
A cautionary tale
Authors: Robert R. Korfhage, Jing-Jye Yang
Venue: ACM SIGIR Forum (1991)

Recently we have been investigating various methods for improving the retrieval of documents. One frequently used context for such studies is to work with a known database and set of queries, where sufficient work has previously been done to establish an "official" set of relevant documents for each query. Working within such a context, we have discovered at least one instance wherein the combination of the document descriptions in the database, the query, and the set of documents deemed relevant foredooms our attempts at retrieval improvement to failure. This note is to caution other researchers against such possibilities, and to recommend that the database in question, that of the National Physical Laboratory (NPL), as represented on Virginia Disk 1, be retired from use.
Dynamic display of computing processes
Authors: John Sigle
Venue: ACM SIGCSE Bulletin (1990)

Dynamic (animated) displays of computing processes such as algorithm execution seem useful in teaching computer science. Not everyone agrees with this view, however, and indeed there are some pedagogical pitfalls. This paper addresses this issue and argues that there is a proper role for such capabilities, provided that sufficient attention is given to careful reasoning about programs.
Analog implementations of auditory models
Authors: Richard F. Lyon
Venue: Proceedings of the workshop on Speech and Natural Language (1991)

The challenge of making cost-effective implementations of auditory models has led us to pursue an analog VLSI micro-power approach. Experiments with the first few generations of analog cochlea chips showed some of both the potential and the problems of this approach. The inherent exponential behavior of MOS transistors in the subthreshold or weak-inversion region leads to nonlinear filter circuits, in which the small-signal and large-signal behaviors can be quite different. Early problems with instability, poor dynamic range, and excessive noise are now understood in terms of the transition behavior between these regions, and this understanding has led us to design filter stages with appropriately compressive behavior, resulting in more robust cochea performance. Several types of correlator circuits to follow the cochlea have also been developed into working demonstrations. Videotapes of circuit outputs and simulations illustrate the recent ideas and progress.
Design and performance evaluation of new massively parallel VLSI mask verification algorithms in JIGSAW
Authors: Erik C. Carlson, Rob A. Rutenbar
Venue: Proceedings of the 27th ACM/IEEE Design Automation Conference (1991)

This paper describes JIGSAW, the massively parallel mask checking system that has evolved from our earlier feasibility study on large-scale, fine-grain parallelism in simple mask checking tasks [1]. Unlike previous systems, JIGSAW parallelizes all phases of the checking process. We describe new techniques to handle all-angle geometry, the first massively parallel mask flattening and multi-layer netlist extraction algorithms, and measurements made comparing JIGSAW, running on a Connection Machine, against industry-standard tools. End-to-end speedups, (i.e., from CIF to errors) range from 19 to 58 over DRACULA, with larger masks producing larger speedups.
A simulation study of the performance of the extra-stage cube and the augmented-shuffle exchange networks under faults
Authors: Abdullah A. Abonamah, Fadi N. Sibai
Venue: ACM SIGSIM Simulation Digest (1992)

In this paper, we conducted a simulation study to compare the performance of the Extra-Stage Cube (ESC) and the Augmented-Shuffle Exchange (ASE) networks in the presence of multiple link failures. The main objective of this study is gain an insight as to which of these two networks can better support graceful degradation under varying network loads and link failure rates. To achieve this task, three performance metrics are introduced, these are throughput, Message-Delivery ratio, and Average Delay Per Message and three simulation experiments using the simulation package COMNET II.5 are designed.The simulation results indicate that with respect to the three performance metrics, the ESC network outperforms the ASE for network size N ge;32 and link MTTF=0.75 hours. However, when the link MTTF=0.12 hours, the ASE network outperforms the ESC network for N lt;64. In both cases, the ESC network outperforms the ASE network when N=64. This result appears to be directly related to the link complexities of the two networks. For large networks, the link complexity of the ASE is much larger than that of the ESC network and accounts for its poorer performance when N lt;32.
The role of the activity adjacency matrix in the critical path method
Authors: Edward Y. H. Lin
Venue: ACM SIGAPL APL Quote Quad (1991)

This paper introduces the use of an activity adjacency matrix in the critical path method to avoid the confusion created by converting the project into its network representation, particularly in performing the cost time trade-offs. A set of APL code was developed to illustrate this point.
Prioritized asynchronism in Ada 9X
Authors: K. C. Elsom
Venue: Proceedings of the fourth international workshop on Real-time Ada issues (1990)

This paper discusses the semantics for asynchronous message passing between prioritized tasks including the case where the messages may themselves be given explicit priority. A highly flexible scheme results that is applicable to a wide range of scheduling algorithms. The impact in the case of a simple priority-inheritance scheduler is explored.
How the Nintendo generation learns
Authors: Elliot Soloway
Venue: Communications of the ACM (1991)

Recently, I was chatting with my son, Daniel (age 7) about Nintendo. I asked him if he could bring it in to school for show and tell and he was horrified! &ldquo;No,&rdquo; he exclaimed, &ldquo;that's not for learning.&rdquo; Well, what do you, dear reader, think about that? Is Nintendo for learning? No one is watching/listening &hellip; go ahead &hellip; admit it &hellip; You don't really like Nintendo. (Of course, when you play Tetris, that is exercising problem-solving skills. Right.) And, afterall, you didn't use all that technology in school, and you learned just fine. So, why do &ldquo;kids these days&rdquo; need all this new multimedia technology, anyhow? That technology just makes it fun and easy to learn&mdash;it's just glitz. And as for calculators.....
Model-Based Visual Feedback Control for a Hand-Eye Coordinated Robotic System
Authors: John T. Feddema, C. S. George Lee, O. Robert Mitchell
Venue: Computer (1992)

The integration of a single camera into a robotic system to control the relative position and orientation between the robot's end-effector and a moving part in real time is discussed. Only monocular vision techniques are considered because of current limitations in the speed of computer vision analysis. The approach uses geometric models of both the part and the camera, as well as the extracted image features, to generate the appropriate robot control signals for tracking. Part and camera models are also used during the teaching stage to predict important image features that appear during task completion.
Self-perceptions and job preferences of entry-level information systems professionals: implications for career development
Authors: Ephraim R. McLean, John R. Tanner, Stanley J. Smits
Venue: ACM SIGCPR Computer Personnel (1991)

This study describes the self-perceptions and job preferences of 938 students majoring in information systems at 37 colleges and universities just prior to their graduation. Scores on a specially-devised Personal Characteristics Inventory (25 items) and Job Preference Inventory (20 items) were factor analyzed as a data reduction technique and treated as dependent variables. Five independent variables (career certainty, sex, type of degree, age, and overall grade point average) accounted for 38 significant differences in the dependent variables.Career certainty, sex, and age were strongly related to self-described work capacities, traits, and behaviors. Undergraduate versus graduate degree candidacy was the variable most strongly influencing the importance the students assigned to specific job characteristics.Based upon these findings, these entry-level IS professionals are profiled according to their characteristics, perceptions, and preferences; and these profiles are then discussed in terms of career development and career management.
The Python compiler for CMU Common Lisp
Authors: Robert A. MacLachlan
Venue: Proceedings of the 1992 ACM conference on LISP and functional programming (1992)

The Python compiler for CMU Common Lisp has been under development for over five years, and now forms the core of a production quality public domain Lisp implementation. Python synthesizes the good ideas from Lisp compilers and source transformation systems with mainstream optimization and retargetability techniques. Novel features include strict type checking and source-level debugging of compiled code. Unusual attention has been paid to the compiler's user interface.
An assumption about computer security (it ain't necessarily so.) (abstract)
Authors: Lee Ohringer
Venue: Proceedings of the 1990 ACM annual conference on Cooperation (1990)

It is often stated that &ldquo;A chain is only as strong as its weakest link.&rdquo; However, this maxim doesn't hold true for Computer Security! Do not despair if there are parts of your organization's computer security practices that defy your best efforts to improve them. You may be able to compensate for weaknesses in one part of your program by beefing-up other parts. For example, software security is one of the links in the computer security chain. For some computers, this link is weak or almost nonexistent. But realize that the computer users are another link in the computer security chain. By strengthening the computer user link, which we can do by improving user awareness, we can more than compensate for weakness in the software security link. By doing so, we also buy time to develop appropriate software security. So don't let the assumption that computer security is only as strong as its weakest link deter you from implementing good security, because it ain't necessarily so.
Using approximation algorithms to design parallel algorithms that may ignore processor allocation (preliminary version)
Authors: Michael T. Goodrich
Venue: Proceedings of the 32nd annual symposium on Foundations of computer science (1991)

A framework is presented for designing parallel algorithms that may ignore processor allocation. A number of fast approximation algorithms are developed, and it is shown how to use these algorithms to simulate any algorithm that fits this framework in a work-preserving fashion on a randomized CRCW PRAM. Several applications of the approach to parallel computational geometry are given.
InternetExpress: An Inter-Desktop Multimedia Data-Transfer Service
Authors: Murugappan Palaniappan, George Fitzmaurice
Venue: Computer (1991)

An integrated desktop data-transfer service called InternetExpress, which was designed to overcome the shortcomings in existing network-based transfer tools with respect to heterogeneity, seamlessness, user-interface simplicity, timeliness and security, is presented. This service allows users to share data conforming to any data standard across heterogeneous environments on the Internet, assuming the environments follow the general principles of the desktop metaphor. InternetExpress is selection-based. A prototype of InternetExpress has been implemented in the Intermedia desktop environment.
Algorithm 707: CONHYP: a numerical evaluator of the confluent hypergeometric function for complex arguments of large magnitudes
Authors: Mark Nardin, W. F. Perger, Atul Bhalla
Venue: ACM Transactions on Mathematical Software (TOMS) (1992)

A numerical evaluator for the confluent hypergeometric function for complex arguments with large magnitudes using a direct summation of Kummer's series is presented. Extended precision subroutines using large arrays to accumulate a single numerator and denominator are ultimately used in a single division to arrive at the final result. The accuracy has been verified through a variety of tests and they show the evaluator to be consistently accurate to 13 significant figures, and on rare occasion accurate to only 9 for magnitudes of the arguments ranging into the thousands in any quadrant in the complex plane. Because the evaluator automatically determines the number of significant figures of machine precision, and because it is written in FORTRAN 77, tests on various computers have shown the evaluator to provide consistently accurate results, making the evaluator very portable. The principal drawback is that, for certain arguments, the evaluator is slow; however, the evaluator remains valuable as a benchmark even in such cases.
An Analysis of Camera Noise
Authors: Robert A. Boie, Ingemar J. Cox
Venue: IEEE Transactions on Pattern Analysis and Machine Intelligence (1992)

The class of cameras that are based on ionization sensors, which includes the most common charge-coupled device (CCD) and vidicon cameras, is examined. Camera signals are shown to be corrupted by direction-dependent stationary electronic noise sources and fluctuations due to the statistical nature of the sensing process. The authors develop and test a model of the inherent noises in cameras. These results are confirmed by measurement, and they suggest a locally stationary model of noise for adaptive signal processing.
The Set Theory of Arithmetic Decomposition
Authors: T. M. Carter, J. E. Robertson
Venue: IEEE Transactions on Computers (1990)

The set theory of arithmetic decomposition is a method of designing complex addition/subtraction circuits at any radix using strictly positional, sign-local number systems. The specification of an addition circuit is simply an equation that describes the inputs and the outputs as weighted digit sets. Design is done by applying a set of rewrite rules known as decomposition operators to the equation. The order in which and weight at which each operator is applied maps directly to a physical implementation, including both multiple-level logic and connectivity. The method is readily automated, and has been used to design some higher radix arithmetic circuits. It is possible to compute the cost of a given adder before the detailed design is complete.
An analysis of soar as an integrated architecture
Authors: John Laird, Mike Hucka, Scott Huffman, Paul Rosenbloom
Venue: ACM SIGART Bulletin (1991)

In this article we provide a brief analysis of the Soar architecture [Laird et al., 1987; Laird et al., 1990; Rosenbloom et al., 1991a] with respect to the issues listed in the preface of this collection.
ConMod: a system for conceptual consistency verification and communication
Authors: Robert E. Braudes, John L. Sibert
Venue: ACM SIGCHI Bulletin (1991)

The ConMod system is a modelling tool for the construction, verification, and communication of user conceptual models. A basic premise behind the research is that consistency at the syntactic and lexical levels cannot counteract conceptual inconsistencies designed into a system, and a working definition of conceptual consistency is maintained in a user-extensible knowledge base. The system designer has the option to test the model for completeness and conceptual consistency based upon high-level knowledge of the types of objects in the model. ConMod also generates conceptual specifications for discussing the model with end users and prototyping and implementation teams. Finally, ConMod allows the conceptual structure of one model to be reused in a different model.
The art of search: a study of art directors
Authors: Sharon R. Garber, Mitch B. Grunes
Venue: Proceedings of the SIGCHI conference on Human factors in computing systems (1992)

We formulated a model of visual search by conducting a work flow study and task analysis of art directors as they searched for images to use in an advertisement. The analysis revealed the presence of artistic and image concepts, flexible structures which guide the search and are molded by them. Analysis results were used to build a model-based interface for visual search. Results from presenting the interface to users indicate that the interface has the potential to make significant contributions to the visual search task, both in time savings and as an aid to the creative process.
Transfer of Learning by Composing Solutions of Elemental Sequential Tasks
Authors: Satinder Pal Singh
Venue: Machine Learning (1992)

Although building sophisticated learning agents that operate in complex environments will require learning to perform multiple tasks, most applications of reinforcement learning have focused on single tasks. In this paper I consider a class of sequential decision tasks (SDTs), called composite sequential decision tasks, formed by temporally concatenating a number of elemental sequential decision tasks. Elemental SDTs cannot be decomposed into simpler SDTs. I consider a learning agent that has to learn to solve a set of elemental and composite SDTs. I assume that the structure of the composite tasks is unknown to the learning agent. The straightforward application of reinforcement learning to multiple tasks requires learning the tasks separately, which can waste computational resources, both memory and time. I present a new learning algorithm and a modular architecture that learns the decomposition of composite SDTs, and achieves transfer of learning by sharing the solutions of elemental SDTs across multiple composite SDTs. The solution of a composite SDT is constructed by computationally inexpensive modifications of the solutions of its constituent elemental SDTs. I provide a proof of one aspect of the learning algorithm.
Optimal Morphological Pattern Restoration from Noisy Binary Images
Authors: Dan Schonfeld, John Goutsias
Venue: IEEE Transactions on Pattern Analysis and Machine Intelligence (1991)

A theoretical analysis of morphological filters for the optimal restoration of noisy binary images is presented. The problem is formulated in a general form, and an optimal solution is obtained by using fundamental tools from mathematical morphology and decision theory. Consideration is given to the set-difference distance function as a measure of comparison between images. This function is used to introduce the mean-difference function as a quantitative measure of the degree of geometrical and topological distortion introduced by morphological filtering. It is proved that the class of alternating sequential filters is a set of parametric, smoothing morphological filters that best preserve the crucial structure of input images in the least-mean-difference sense.
State space exploration in Markov models
Authors: Edmundo de Souza e Silva, Pedro Mejiá Ochoa
Venue: Proceedings of the 1992 ACM SIGMETRICS joint international conference on Measurement and modeling of computer systems (1992)

Performance and dependability analysis is usually based on Markov models. One of the main problems faced by the analyst is the large state space cardinality of the Markov chain associated with the model, which precludes not only the model solution, but also the generation of the transition rate matrix. However, in many real system models, most of the probability mass is concentrated in a small number of states in comparison with the whole state space. Therefore, performability measures may be accurately evaluated from these &ldquo;high probable&rdquo; states. In this paper, we present an algorithm to generate the most probable states that is more efficient than previous algorithms in the literature. We also address the problem of calculating measures of interest and show how bounds on some measures can be efficiently calculated.
Instrumentation for a massively parallel MIMD application
Authors: R. R. Glenn, D. V. Pryor
Venue: ACM SIGMETRICS Performance Evaluation Review (1991)

This paper describes an application implemented on a simulated machine called Horizon. One purpose of this study is to investigate some of the features of a possible future machine (or class of machines) with a view toward deciding, early on in the research cycle, where problems may come up, what features should be added or strengthened, and what proposed features seem to be unnecessary. Another purpose is to learn more about how to program, instrument and debug a shared memory, massively parallel MIMD computer, and to begin to answer some of the questions: What tools does a programmer need to debug this type of machine? How can a programmer know if the machine is performing well? How can bottlenecks be identified? How can the massive amount of instrumentation information be condensed and presented to a user in a way that makes sense?