ppxscal/embedding_network huggingface dataset:
Non-convex contour reconstruction
Authors: P. Alevizos, J. D. Boissonnat, M. Yvinec
Venue: Journal of Symbolic Computation (1990)

We present algorithms to reconstruct the planar cross-section of a simply connected object from data points measured by rays. The rays are semi-infinite curves representing, for example, the laser beam or the articulated arms of a robot moving around the object. This paper shows that the information provided by the rays is crucial (though generally neglected) when solving 2-dimensional reconstruction problems. The main property of the rays is that they induce a total order on the measured points. This order is shown to be computable in optimal time O(n log n). The algorithm is fully dynamic and allows the insertion or the deletion of a point in O(log n) time. From this order a polygonal approximation of the object can be deduced in a straightforward manner. However, if insufficient data are available or if the points belong to several connected objects, this polygonal approximation may not be a simple polygon or may intersect the rays. This can be checked in O(n log n) time. The order induced by the rays can also be used to find a strategy for discovering the exact shape of a simple (but not necessarily convex) polygon by means of a minimal number of probes. When each probe outcome consists of a contact point, a ray measuring that point and the normal to the object at the point, we have shown that 3n-3 probes are necessary and sufficient if the object has n non-colinear edges. Each probe can be determined in O(log n) time yielding an O(n log n)-time 0(n)-space algorithm. When each probe outcome consists of a contact point and a ray measuring that point but not the normal, the same strategy can still be applied. Under a mild condition, 8n-4 probes are sufficient to discover a shape that is almost surely the actual shape of the object.
A Theory of Fault-Based Testing
Authors: L. J. Morell
Venue: IEEE Transactions on Software Engineering (1990)

A theory of fault-based program testing is defined and explained. Testing is fault-based when it seeks to demonstrate that prescribed faults are not in a program. It is assumed that a program can only be incorrect in a limited fashion specified by associating alternate expressions with program expressions. Classes of alternate expressions can be infinite. Substituting an alternate expression for a program expression yields an alternate program that is potentially correct. The goal of fault-based testing is to produce a test set that differentiates the program from each of its alternates. A particular form of fault-based testing based on symbolic execution is presented. In symbolic testing, the output from the system is an expression in terms of the input and the symbolic alternative. Equating this with the output from the original program yields a propagation equation whose solutions determine those alternatives which are not differentiated by this test. Since an alternative set can be infinite, it is possible that no finite test differentiates the program from all its alternates. Circumstances are described as to when this can be decided.
Using the campus network to link faculty, staff, and graduate students with their children
Authors: Sue Stager
Venue: ACM SIGUCCS Newsletter (1991)

This past fall, University Computing Services provided a computer hook-up at the Indiana University - Bloomington campus day care center, enabling four-, five-, and six-year-old children to communicate with their parents during the day. The parents are faculty, staff, and students at Indiana University, and have access to computers in their office or at public computing sites throughout campus.
VAX-11 Fortran: a flaw in efficient code generation
Authors: M. R. Khalil
Venue: ACM SIGPLAN Fortran Forum (1991)

This report describes the following flaws in VAX-11 Fortran version 3.5-62 compiler that may cause erroneous results without any warning. (1) It fails to detect an overflow condition in integer addition and subtraction; (2) it violates the semantic requirement of Fortran language with equal precedence operations of addition and subtraction.
The mismatch between technology planning and user needs
Authors: Arthur E. Paris
Venue: ACM SIGUCCS Newsletter (1991)

The professional and trade literature about computing as work activity obscures key features of the daily context in which computing technology is used. Organizational managers and their superiors in charge of this technology lack a clear understanding of the mundane context of people's work and computer use. Consequently, they misunderstand the issues surrounding its use and adoption, and, absent a more realistic view, will be unable to deliver on their and its promises of significantly improved productivity.
EUG'91 meeting notes
Authors: Peter R. Wilson
Venue: ACM SIGMOD Record (1992)

The first annual meeting of the EXPRESS Users Group was held in Houston, Texas on 17-18 October 1991. There was a good international audience at the conference, two thirds of whom were from North America with the remainder from several European countries and Japan.
Interprocess Communication Dependency on Network Load
Authors: Alessandro Braccini, Alberto Del Bimbo, Enrico Vicario
Venue: IEEE Transactions on Software Engineering (1991)

Results of an analysis of the communication performance as perceived by the application layer in the presence of background load are presented. The analysis was carried out on two distinct protocol suites, TCP/IP and XNS, on a single Ethernet LAN with personal computer workstations. Service times for a reliable transfer and an unreliable transmission as perceived by the application layer were measured. An appropriate model of the reliable transfer process was used to derive service time analytical estimates. Owing to the close relation between measured and estimated values, the model was used to identify the major sources of delay and to evaluate the effects of possible improvements. The most important causes affecting the transport layer performance as background load increases are identified, and different strategies are examined in order to reduce their impact. The improvement margin offered by the implementation of a lightweight transport protocol specifically tailored to the requirements of a bulk data transfer over an Ethernet is addressed.
Object-oriented video: interaction with real-world objects through live video
Authors: Masayuki Tani, Kimiya Yamaashi, Koichiro Tanikoshi, Masayasu Futakawa, Shinya Tanifuji
Venue: Proceedings of the SIGCHI conference on Human factors in computing systems (1992)

Graphics and live video are widely employed in remotely-controlled systems like industrial plants. Interaction with live video is, however, more limited compared with graphics as users cannot interact with objects being observed in the former. Object-Oriented Video techniques are described allowing object-oriented interactions, including the use of real-world objects in live video as reference cues, direct manipulation of them, and graphic overlays based on them, which enable users to work in a real spatial context conveyed by the video. Users thereby understand intuitively what they are operating and see the result of their operation.
Compact input coding for speech recognition by neural net (abstract)
Authors: Thomas M. English, Louis C. Boggess
Venue: Proceedings of the 1990 ACM annual conference on Cooperation (1990)

Error back-propagation has been used to train a multilayer perceptron to classify an individual's utterances of digits. The network has made no errors in classifying 300 new utterances, and has exhibited robust performance with gross variations in speaking style and signal-to-noise ratio. The novelty of the approach is the way in which temporal information is encoded for use by the perceptron. Specifically, the input is a pattern of decaying activations in a self-organized map of speech spectra. At uniform steps in time, the unit in the map that most accurately represents the current speech sound is fully activated. The activation of the unit subsequently decays exponentially, and at any time the level of activation of a unit indicates how recently its corresponding speech sound has occurred. One may imagine the map as a screen of luminescent elements and the speech signal as a point of light moving across the screen. The role of the network is to classify trajectories of digits on the screen. We have found that the rate of decay in the feature map is not an important factor in isolated digit recognition. Decay rate is expected to be a critical factor in training the perceptron to spot utterances of digits in fluent speech, however. Use of the digit-classifier in a &ldquo;bootstrap&rdquo; training procedure for a continuous speech recognizer is proposed.
Grace meets the &ldquo;real world&rdquo;: tutoring COBOL as a second language
Authors: Rob Radlinski, Jean McKendree
Venue: Proceedings of the SIGCHI conference on Human factors in computing systems (1992)

Grace is an intelligent tutoring system for COBOL which has been used to teach both novice and experienced programmers. While the tutor was quite effective in several classes and was designed with cognitive and interface principles in mind, we discuss a number of interesting issues that we have discovered when novice and experienced programmers used the tutor. Most of these problems are related to incompatibilities between the tutor interactions and the students' expectations in two areas: (1) the interactions with the tutor versus the interactions in their usual work environment and (2) the way in which experienced programmers solve problems. We describe these issues along with our solutions in the revised version of the tutor.
Efficient Algorithms for Selection of Recovery Points in Tree Task Models
Authors: Subhada K. Mishra, Vijay V. Raghavan, Nian-Feng Tzeng
Venue: IEEE Transactions on Software Engineering (1991)

Efficient solutions to the problem of optimally selecting recovery points are developed. The solutions are intended for models of computation in which task precedence has a tree structure and a task may fail due to the presence of faults. An algorithm to minimize the expected computation time of the task system under a uniprocessor environment has been developed for the binary tree model. The algorithm has time complexity of O(N/sub 2/), where N is the number of tasks, while previously reported procedures have exponential time requirements. The results are generalized for an arbitrary tree model.
Comprehensive Testing of Multistage Interconnection Networks
Authors: Antoine Mourad, Banu Özden, Miroslaw Malek
Venue: IEEE Transactions on Computers (1991)

The authors present efficient methods for testing packet-switched multistage interconnection networks. In addition to testing the data paths and routing capabilities, tests for detecting faults in the control circuitry including the conflict resolution capabilities are provided. Using a general model of the switch, testing sequences are constructed for the internal functions of the f*f switch requiring only O(f/sup 2/2/sup f/) tests in the case of round-robin priority and O(f2/sup f-1/) in the case of fixed priority (f is usually a constant that is less than or equal to eight). Algorithms are then presented to test the entire network using at most twice the number of tests needed to test a switch, independently of the network size, which results in O(log N) testing time for an N-processor network. It is shown that the method achieves higher coverage and several-orders-of-magnitude reduction in the testing time of complex multiprocessor systems compared to previous methods.
Performance Prediction and Evaluation of Parallel Processing on a NUMA Multiprocessor
Authors: Xiaodong Zhang, Xiaohan Qin
Venue: IEEE Transactions on Software Engineering (1991)

The efficiency of the basic operations of a NUMA (nonuniform memory access) multiprocessor determines the parallel processing performance on a NUMA multiprocessor. The authors present several analytical models for predicting and evaluating the overhead of interprocessor communication, process scheduling, process synchronization, and remote memory access, where network contention and memory contention are considered. Performance measurements to support the models and analyses through several numerical examples have been done on the BBN GP1000, a NUMA shared-memory multiprocessor. Analytical and experimental results give a comprehensive understanding of the various effects, which are important for the effective use of NUMA shared-memory multiprocessor. The results presented can be used to determine optimal strategies in developing an efficient programming environment for a NUMA system.
SCinet '91&mdash;Supercomputing '91s gigabit network
Authors: Alex Nussbaum
Venue: ACM SIGSMALL/PC Notes (1992)

Albuquerque, NM: In a spirit of cooperation unparalleled in the computing business, technicians, company CEOs, scientists, and engineers worked together to create SCinet '91, a gigabit network designed specifically for the fourth conference on high-performance computing, SUPERCOMPUTING '91, held November 18-22 in Albuquerque. In addition to hundreds of person-hours in the past few weeks and several months of planning, donations of cable and equipment came from Cray Research, IBM, Digital Equipment, USWest Communications, Network Systems, Ultra Network Technologies, SynOptics Communications, Broadband Communications Products, Interop, Aquila Group, and Siecor to develop this unique example of the cooperation and networking envisioned in the National Research and Education Network (NREN). NREN is part of the President's High Performance Computing and Communication initiative, a bill that just passed in the House of Representatives and is currently in the Senate. D. Allan Bromley, Science Advisor to the President, gave the keynote address at SUPERCOMPUTING '91 and expressed strong hope that the bill would pass.
Adaptive admission congestion control
Authors: Zygmunt Haas
Venue: ACM SIGCOMM Computer Communication Review (1991)

In this paper, we describe a novel congestion control scheme for high-speed networks. The scheme is based on periodic transmission through the network of time-stamped sampling packets that sense the congestion status of the network. Upon reception, the sampling packet delays are calculated, averaged, and used to determine the state of the network. The information on the state of the network is then used to drive the network adaptive admission control. The major advantage of the proposed scheme over conventional congestion control techniques is that it copes with traffic surges that are shorter than the network round-trip delay. This is achieved by controlling traffic admission with continuous estimate of the network state. The scheme is targeted toward networks that carry aggregated traffic, and can be applied to ATM-based networks.
Time-sequenced DMA for multimedia computers
Authors: Stuart C. Wray
Venue: ACM SIGARCH Computer Architecture News (1991)

Current computer architectures are well suited to the transfer of large amounts of data where latency is not important, and to transfering small amounts of data where latency is important. However, when latency is important and the quantity of data is large, today's computers do not perform so well. In this paper I describe a variety of scatter-gather DMA in which large amounts of data can be transfered with low latency through a computer system by using synchronised clocks in the transmitting and receiving devices.
Applications of parametric searching in geometric optimization
Authors: Pankaj K. Agarwal, Micha Sharir, Sivan Toledo
Venue: Proceedings of the third annual ACM-SIAM symposium on Discrete algorithms (1992)

We present several applications in computational geometry of Megiddo's parametric searching technique. These applications include; (1) Finding the minimum Hausdorff distance in the Euclidean metric between two polygonal regions under translation; (2) Computing the biggest line segment that can be placed inside a simple polygon; (3) Computing the smallest width annulus that can contain a given set of points in the plane; (4) Solving the 1-segment center problem&mdash;given a set of points in the plane, find a placement for a given line segment (under translation and rotation) which minimizes the largest distance from the segment to the given points; (5) Given a set of n points in 3-space, finding the largest radius r such that if we place a ball of radius r around each point, no segment connecting a pair of points is intersected by a third ball. Besides obtaining efficient solutions to all these problems (which, in every case, either improve considerably previous solutions or are the first non-trivial solutions to these problems), our goal is to demonstrate the versatility of the parametric searching technique.
Graphical fisheye views of graphs
Authors: Manojit Sarkar, Marc H. Brown
Venue: Proceedings of the SIGCHI conference on Human factors in computing systems (1992)

A fisheye lens is a very wide angle lens that shows places nearby in detail while also showing remote regions in successively less detail. This paper describes a system for viewing and browsing planar graphs using a software analog of a fisheye lens. We first show how to implement such a view using solely geometric transformations. We then describe a more general transformation that allows hierarchical, structured information about the graph to modify the views. Our general transformation is a fundamental extension to the previous research in fisheye views.
The metric based compiler: a current requirement
Authors: Reiner Dumke, Kerstin Neumann, Kerstin Stoeffler
Venue: ACM SIGPLAN Notices (1992)

This paper describes the situation in the use of software metrics for the development of software. Today many basic metrics - including code metrics - are applied in very different tools for the development of software. But the user is not sure to obtain the correct instructions for the most efficient implementation in the sense of the lowest psychological complexity. The application of the classical code metrics (Halstead's software science and McCabe's cyclomatic number) is not possible for all languages.Therefore it is necessary that the compiler writer or the compiler writing systems includes the meaningful code metrics in the process of the compiler construction. The compiler writer must know this metrics for "his" language.This paper gives some directions for the derivation of code metrics for different languages and their use as metric based software tools.
The user command processor
Authors: Jim Weigang
Venue: Proceedings of the international conference on APL '91 (1991)

The User Command Processor is a new feature of several APL*PLUS systems which allows users to define commands, analogous to system commands, that can be executed from within any workspace. This enhancement is implemented by means of two simple changes to the APL interpreter. Coupled with a suite of two-dozen predefined commands, the result is a file-based program storage and execution environment that integrates many important features not provided in standard APL systems. Using the command processor, applications of unlimited size can be developed, run, and maintained without many of the headaches that are characteristic of workspace-based systems. This paper describes the basic methods whereby the command processor operates, provides an overview of the predefined commands, shows how a new command can be defined, and illustrates how a large application can be built using the command processor.
Analysis of 2-D Occlusion by Subtracting Out
Authors: Julian R. Ullmann
Venue: IEEE Transactions on Pattern Analysis and Machine Intelligence (1992)

A provably correct polynomial-time algorithm for complete systematic analysis of occlusion in synthetically generated noise-free pictures of 2-D objects is introduced. The algorithm first recognizes occluding objects and then ignores the mismatch with pixels in occluding objects while recognizing occluded objects by template matching.
PARASPICE: a parallel circuit simulator for shared-memory multiprocessors
Authors: Gung-Chung Yang
Venue: Proceedings of the 27th ACM/IEEE Design Automation Conference (1991)

This paper presents a general approach to parallelizing direct method circuit simulation. The approach extracts parallel tasks at the algorithmic level for each compute-intensive module and therefore is suitable for a wide range of shared-memory multiprocessors. The implementation of the approach in SPICE2 resulted in a portable parallel direct circuit simulator, PARASPICE. The superior performance of PARASPICE is demonstrated on an 8-CE Alliant FX/80 using a number of benchmark circuits.
A general approximation technique for constrained forest problems
Authors: Michel X. Goemans, David P. Williamson
Venue: Proceedings of the third annual ACM-SIAM symposium on Discrete algorithms (1992)

We present a general approximation technique for a large class of graph problems. Our technique mostly applies to problems of covering, at minimum cost, the vertices of a graph with trees, cycles or paths satisfying certain requirements. In particular, many basic combinatorial optimization problems fit in this framework, including the shortest path, minimum spanning tree, minimum-weight perfect matching, traveling salesman and Steiner tree problems. Our technique produces approximation algorithms that run in O(n2 log n) time and come within a factor of 2 of optimal for most of these problems. For instance, we obtain a 2-approximation algorithm for the minimum-weight perfect matching problem under the triangle inequality. Our running time of O(n2 log n) time compares favorably with the best strongly polynomial exact algorithms running in O(n3) time for dense graphs. A similar result is obtained for the 2-matching problem and its variants.We also derive the first approximation algorithms for many NP-complete problems, including the non-fixed point-to-point connection problem, the exact path partitioning problem and complex location-design problems. Moreover, for the prize-collecting traveling salesman or Steiner tree problems, we obtain 2-approximation algorithms, therefore improving the previously best-known performance guarantees of 2.5 and 3, respectively [4].
Performance variation across benchmark suites
Authors: Carl Ponder
Venue: ACM SIGMETRICS Performance Evaluation Review (1990)

The performance ratio between two systems tends to vary across different benchmarks. Here we study this variation as a "signature" or "fingerprint" of the systems under consideration. This "fingerprint" can be used to guess the performance of programs not represented in a benchmark suite, assess the breadth and credibility of the benchmark suite, and infer details of the system design.
Using Flat Concurrent Prolog in System Modeling
Authors: Yoheved Dotan, Benjamin Arazi
Venue: IEEE Transactions on Software Engineering (1991)

The flat concurrent Prolog (FCP) language, which enables the implementation of synchronization through data flow, communication through shared variables, parallelism through the reduction of the AND components in the clause's body, and indeterminacy through guarded commands, is discussed. It is shown that FCP, used in conjunction with Petri net methods, forms a powerful tool in the modeling of parallel systems that involve concurrency. The simulation of systems represented by various types of Petri nets is achieved using the reduction process of FCP. AND parallelism supports free competition among conflicting enabled transitions. A structural analysis of systems is provided using the metaprogramming technique.