ppxscal/embedding_network huggingface dataset:
File archive activity in a supercomputing environment
Authors: David W. Jensen, Daniel A. Reed
Venue: Proceedings of the 7th international conference on Supercomputing (1993)

The National Center for Supercomputing Applications (NCSA) at the University of Illinois typifies current, high-performance computing centers that support a diverse user base of both academic and industrial accounts. The data requirements of this user community, coupled with resource constraints, mandate the use of an archival file system. This paper analyzes the spatial and temporal patterns of file archive transactions on the NCSA file archive. Analysis of archive transaction traces shows that the access patterns differ from those observed during studies of secondary storage systems: the files are larger, there are large temporal and spatial variations in transaction patterns, and a small number of research groups can easily account for twenty percent of the total traffic.
Challenges facing researchers using multimedia data: tools for layering significance
Authors: Ricki Goldman-Segall
Venue: ACM SIGGRAPH Computer Graphics (1994)

Two distinct communities of visual media users have begun to influence each other over the last few decades --- those who use media as forms of art and entertainment, and those, from a variety of knowledge domains, who use media forms as tools to explain, illustrate or communicate. From the entertainment and cinematic world, a rich grammar has evolved which describes a range of identifiable genres and basic structures --- what Davenport and her research team at MIT refer to as primitives (1991).However, in the world of academia, we have just begun to think deeply about non-print media as being other than vehicles for representing our knowledge via slides, tapes, overheads, images in books and various other visualization or acoustic aids. This article will show why these two communities have much to learn from each other in the light of emerging multimedia networks. First, I will describe the challenges facing researchers who use multimedia data, and then I will explain several features of an existing multimedia research tool which address these challenges.
Original Contribution: A method for improving the real-time recurrent learning algorithm
Authors: Thierry Catfolis
Venue: Neural Networks (1993)

Williams and Zipser (1989) proposed two analogue learning algorithms for fully recurrent networks. The first method is an exact gradient-following algorithm for problems where data consists of epochs. The second method, called the Real-Time Recurrent Learning (RTRL) algorithm, uses data described by a temporal stream of inputs and outputs, without time marks or epochs. In this paper we describe a new implementation of this RTRL algorithm. This improved implementation makes it possible to increase the performance of the learning algorithm during the training phase by using some a priori knowledge about the temporal necessities of the problem. The reduction of the computational expense of the training enables the use of this algorithm for more complex problems. Some simulations of a process control task demonstrate the properties of this algorithm.
Precision synchronization of computer network clocks
Authors: David L. Mills
Venue: ACM SIGCOMM Computer Communication Review (1994)

This paper builds on previous work involving the Network Time Protocol, which is used to synchronize computer clocks in the Internet. It describes a series of incremental improvements in system hardware and software which result in significantly better accuracy and stability, especially in primary time servers directly synchronized to radio or satellite time services. These improvements include novel interfacing techniques and operating system features. The goal in this effort is to improve the synchronization accuracy for fast computers and networks from the tens of milliseconds regime of the present technology to the submillisecond regime of the future.In order to assess how well these improvements work, a series of experiments is described in which the error contributions of various modern Unix system hardware and software components are calibrated. These experiments define the accuracy and stability expectations of the computer clock and establish its design parameters with respect to time and frequency error tolerances. The paper concludes that submillisecond accuracies are indeed practical, but that further improvements will be possible only through the use of temperature-compensated local clock oscillators.
The Cobbler's children: applying total quality management to business process improvement, information engineering and software engineering
Authors: William E. Hefley
Venue: ACM SIGSOFT Software Engineering Notes (1993)

This paper describes an approach to, and the relationship among, Business Process Improvement, Business Case Analysis, Information Engineering, and Total Quality Management. This approach is shown to not only complement existing software engineering approaches; but to also provide a framework for implementing continuous improvement processes focused on improving the quality of the organization's processes, services and products.
An old-fashioned recipe for real time
Authors: Martín Abadi, Leslie Lamport
Venue: ACM Transactions on Programming Languages and Systems (TOPLAS) (1994)

Traditional methods for specifying and reasoning about concurrent systems work for real-time systems. Using TLA (the temporal logic of actions), we illustrate how they work with the examples of a queue and of a mutual-exclusion protocol. In general, two problems must be addressed: avoiding the real-time programming version of Zeno's paradox, and coping with circularities when composing real-time assumption/guarantee specifications. Their solutions rest on properties of machine closure and realizability.
Enhancements of ANALYZE: a computer-assisted analysis system for linear programming
Authors: Harvey J. Greenberg
Venue: ACM Transactions on Mathematical Software (TOMS) (1993)

This describes enhancements to provide more advanced computer-assisted analysis of instances of linear programming models. Three categories of enhancements are described: views, engines for obtaining information, and rule-based advising. Examples of their uses include redundancy and infeasiblity diagnoses.
Maya: a simulation platform for distributed shared memories
Authors: Divyakant Agrawal, Manhoi Choy, Hong Va Leong, Ambuj K. Singh
Venue: ACM SIGSIM Simulation Digest (1994)

Maya is a simulation platform for evaluating the performance of parallel programs on parallel architectures. It allows the rapid prototyping of memory protocols with varying degrees of coherence and facilitates the study of the impact of these protocols on application programs. The design of Maya and its simulation mechanism are discussed. Performance results on architectural simulation with different memory coherence protocols are presented. Parallel discrete event simulation techniques are adopted for the execution-driven simulation of parallel architectures.
Efficient distribution-free learning of probabilistic concepts
Authors: Michael J. Kearns, Robert E. Schapire
Venue: Journal of Computer and System Sciences (1994)

In this paper we investigate a new formal model of machine learning in which the concept (Boolean function) to be learned may exhibit uncertain or probabilistic behavior-thus, the same input may sometimes be classified as a positive example and sometimes as a negative example. Such probabilistic concepts (or p-concepts) may arise in situations such as weather prediction, where the measured variables and their accuracy are insufficient to determine the outcome with certainty. We adopt from the Valiant model of learining [28] the demands that learning algorithms be efficient and general in the sense that they perform well for a wide class of p-concepts and for any distribution over the domain. In addition to giving many efficient algorithms for learning natural classes of p-concepts, we study and develop in detail an underlying theory of learning p-concepts.
A note on slowing Quicksort
Authors: R. Chaudhuri, A. C. Dempster
Venue: ACM SIGCSE Bulletin (1993)

We present a simple linear time algorithm for generating a worst case sequence for Quicksort when the pivot element is chosen as the middle elements of the (sub)array in each pass.
PARDES: a data-driven oriented active database model
Authors: Opher Etzion
Venue: ACM SIGMOD Record (1993)

Most active database models adopted an event-driven approach in which whenever a given event occurs the database triggers some actions. Many derivations are data-driven by nature, deriving the values of data-elements as a function of the values of other derived data-elements. The handling of such rules by current active databases suffers from semantic and pragmatic fallacies. This paper explores these fallacies and reports about the PARDES language and supporting architecture, aiming at the support of data-driven rules, in an active database framework.
Real-time replication garbage collection
Authors: Scott Nettles, James O'Toole
Venue: Proceedings of the ACM SIGPLAN 1993 conference on Programming language design and implementation (1993)

We have implemented the first copying garbage collector that permits continuous unimpeded mutator access to the original objects during copying. The garbage collector incrementally replicates all accessible objects and uses a mutation log to bring the replicas up-to-date with changes made by the mutator. An experimental implementation demonstrates that the costs of using our algorithm are small and that bounded pause times of 50 milliseconds can be readily achieved.
Integration of different system engineering methods using an object-oriented model
Authors: Horst D. Clausen, Anton Hofmann, Gabriele H. Pawlitzek
Venue: ACM SIGPLAN OOPS Messenger (1993)

The development of large, complex systems consisting of both hardware and software normally involves several companies and/or development teams for the development of the different subsystems forming the entire system. Depending on the kind of subsystem to be developed, these different development teams normally use different system engineering methodologies and/or tool sets to produce their subsystems. However, the usage of different methodologies and tools makes technical management and quality assurance for the entire development effort a difficult task. Therefore the development as well as the maintenance of future systems with their increasing size and complexity requires a common frame for the entire system development and maintenance effort covering different kinds of subsystems, like graphical user interfaces, database systems, expert systems, real-time systems, and so on. This common frame should support the separate and independent development of the different subsystems by different subcontractors using different system engineering methods, the integration of these subsystems to the entire system as well as the maintenance of the entire system. A hierarchical object-oriented model for the encapsulation and integration of different system engineering methods can serve as this common frame, providing traceability from the system requirements model to the implemented system while giving each subsystem development team full scope in choosing the system engineering method most suitable for a specific subsystem. The approach underlying this object-oriented model is the encapsulation of the different subsystems in &ldquo;high-level objects,&rdquo; which can be either further decomposed into &ldquo;high-level object&rdquo; or described in more detail using any appropriate system engineering method. The integration of these &ldquo;high-level objects&rdquo; to the entire system is supported by a &ldquo;definition object&rdquo; on each layer of each system engineering models and the different &ldquo;high-level objects.&rdquo;
Perceptual vs. hardware performance in advanced acoustic interface design
Authors: Elizabeth M. Wenzel
Venue: Proceedings of the INTERACT '93 and CHI '93 conference on Human factors in computing systems (1993)

This panel brings together experts in the field of non-speech auditory displays with points of view ranging from long-term basic research in human perception to the timely production of useable tools in commercial systems. The panel will examine issues of perceptual validity and engineering performance from several different perspectives representative of current work in the field, and discuss how such issues can or should impact decisions made during technology development. Panelists' perspectives include: levels of analysis in designing and using auditory interfaces (Gaver), an example of what can be learned about implementation requirements for low-level psychophysical studies (Wenzel), designing integrated systems to encompass sonification in a three-dimensional environment (Foster), issues in the study of information transfer in representational acoustic signals (Levkowitz), and the design of a generalized technology platform for acoustic signal presentation (Powell).
Can visibility graphs be represented compactly?
Authors: Pankaj K. Agarwal, Noga Alon, Boris Aronov, Subhash Suri
Venue: Proceedings of the ninth annual symposium on Computational geometry (1993)

We consider the problem of representing the visibility graph of line segments as a union of cliques and bipartite cliques. Given a graph G, a family G=G1,G2,&ldots;,Gk is called a clique cover of G if (i) each Gi is a clique or a bipartite clique, and (ii) the union of Gi is G. The size of the clique cover G is defined as i=1kni , where ni is the number of vertices in Gi. Our main result is that there exist visibility graphs of n nonintersecting line segments in the plane whose smallest clique cover has size Wn2/log 2n . An upper bound of On2/logn on the clique cover follows from a well-known result in extremal graph theory. On the other hand, we show that the visibility graph of a simple polygon always admits a clique cover of size Onlog3 n , and that there are simple polygons whose visibility graphs require a clique cover of size Wnlogn .
What causes a trap in IEEE-754 floating-point?
Authors: Fred Tydeman
Venue: ACM SIGNUM Newsletter (1994)

In the ANSI/IEEE Std 754-1985 (IEEE Standard for Binary Floating-point Arithmetic), and the ANSI/IEEE Std 854-1987 (IEEE Standard for Radix-Independent Floating-Point Arithmetic), is signaling a trap an "edge-triggered" or a "level-sensitive" event? Does it matter if an exception is signaled by an arithmetic operation versus a user setting a status flag?
Bump Shading for Volume Textures
Authors: Nelson L. Max, Barry G. Becker
Venue: IEEE Computer Graphics and Applications (1994)

Bump mapping was introduced as a method of rendering realistic shading on bumpy surfaces, without actually rendering a full 3D model of the bumps. Bump mapping works well for parameterized surfaces. The authors interpret the 3D texture as a displacement function to be added to the surface position.
E-mail court case: Epson America
Authors: Andrew Clement
Venue: ACM SIGOIS Bulletin (1993)

"When Alana Shoars arrived for work at Epson America one morning in January 1990, she discovered her supervisor reading and printing out electronic mail messages between other employees. As electronic mail administrator, Ms. Shoars was appalled. When she had trained employees to use the computerized system, Ms. Shoars told them their mail was private. Now a company manager was violating that trust.When she questioned the practice, Ms. Shoars said, she was told to mind her own business. A day later, she said she was fired for insubordination. She has since filed a $1 million wrongful termination suit.. . . She still bristles about Epson: 'You don't read other people's mail, just as you don't listen to their phone conversations. Right is right, and wrong is wrong.'Michael Simmons, chief information officer at the Bank of Boston, disagrees completely, 'If the corporation owns the equipment and pays for the network, that asset belongs to the company and it has a right to look and see if people are using it for purposes other than running the business,' he said." (excerpt from Rifkin, NY Times, Dec. 8, 1991)
Functional composition algorithms via blossoming
Authors: Tony D. DeRose, Ronald N. Goldman, Hans Hagen, Stephen Mann
Venue: ACM Transactions on Graphics (TOG) (1993)

In view of the fundamental role that functional composition plays in mathematics, it is not surprising that a variety of problems in geometric modeling can be viewed as instances of the following composition problem: given representations for two functions F and G, compute a representation of the function H = F o G. We examine this problem in detail for the case when F and G are given in either Be&acute;zier or B-spline form. Blossoming techniques are used to gain theoretical insight into the structure of the solution which is then used to develop efficient, tightly codable algorithms. From a practical point of view, if the composition algorithms are implemented as library routines, a number of geometric-modeling problems can be solved with a small amount of additional software.
A cross-cultural comparison of personal computer utilization by managers: United States vs. Republic of South Africa
Authors: Charles H. Mawhinney, Albert L. Lederer, William John Dunn du Toit
Venue: Proceedings of the 1993 conference on Computer personnel research (1993)

This paper reports on research in progress which compares personal computer (PC) utilization by 105 managers in the United States with a similar set of 85 managers in the Republic of South Africa. The analysis completed to date has indicated, among other things, that 1) average weekly computer use time was higher in South Africa, 2) PCs in the United States were more accessible, and 3) users in the United States were generally more satisfied with their systems. Future analysis will focus on resolving which of the observed differences were attributable to cultural rather than sampling differences.
Multiapplication Support in a Parallel-Program Performance Tool
Authors: R. Bruce Irvin, Barton P. Miller
Venue: IEEE Parallel Distributed Technology: Systems Technology (1994)

We added new features for analyzing multiple programs to the IPS-2 parallel-program performance tools and were surprised at the wide range of performance problems for which this modified IPS-2 can be used. With multiapplication IPS-2, programmers can simultaneously run and analyze cooperating or contending applications; combine performance displays and metrics of multiple applications or multiple versions of the same application to directly compare performance; analyze critical paths of execution for individual applications, for a single application and the applications with which it interacts, or for entire workloads; study how the application workload performance affects the hardware, operating system, and network performance; study an application's evolution through multiple versions, hardware platforms, or input sets; study a workload's aggregate behavior, how applications interact, or how individual applications perform in the presence of other applications; and compare the measured performance of a program with predictions made by simulations or analytical models. This modified parallel-program performance tool analyzes multiple applications in a single session, allowing better performance tuning than is possible when programs are run in isolation.
Domain-specific software architecture (DSSA) frequently asked questions (FAQ)
Authors: Will Tracz
Venue: ACM SIGSOFT Software Engineering Notes (1994)

The Advanced Research Projects Agency's Domain-Specific Software Architecture (DSSA) Project has been the focal point of much interest in the software engineering community. This paper provides a list of "Frequently Asked Questions" (FAQ)1. For a more thorough treatment of DSSA, the reader should consult "Architecture-Based Acquisition and Development of Software: Guidelines and Recommendations from the ARPA Domain-Specific Software Architecture (DSSA) Program by Dr. Frederick Hayes-Roth (see address below).
A pump for rapid, reliable, secure communication
Authors: Myong H. Kang, Ira S. Moskowitz
Venue: Proceedings of the 1st ACM conference on Computer and communications security (1993)

Communication from a low- to a high-level system without acknowledgements will be unreliable; with acknowledgements, it can be insecure. We propose to provide quantifiable security, acceptable reliability, and minimal performance penalties by interposing a device (called the Pump) to push messages to the high system and provide a controlled stream of acknowledgements to the low system.This paper describes how the Pump supports the transmission of messages upward and limits the capacity of the covert timing channel in the acknowledgement stream without affecting the average acknowledgement delay seen by the low system or the message delivery delay seen by the high system in the absence of actual Trojan horses. By adding random delays to the acknowledgment stream, we show how to further reduce the covert channel capacity even in the presence of cooperating Trojan horses in both the high and low systems. We also discuss engineering trade-offs relevant to practical use of the Pump.
On the topological shape of planar Voronoi diagrams
Authors: A. Corbalan, M. Mazon, T. Recio, F. Santos
Venue: Proceedings of the ninth annual symposium on Computational geometry (1993)

Voronoi diagrams in the plane for strictly convex distances have been studied in [3], [5] and [7]. These distances induce the usual topology in the plane and, moreover, the Voronoi diagrams they produce enjoy many of the good properties of Euclidean Voronoi diagrams. Nevertheless, we show (Th.1) that it is not possible to transform, by means of a bijection from the plane into itself, the computation of such Voronoi diagrams to the computation of Euclidean Voronoi diagrams (except in the trivial case of the distance being affinely equivalent to the Euclidean distance). The same applies if we want to compute just the topological shape of a Voronoi diagram of at least four points (Th.2). Moreover, for any strictly convex distance not affinely equivalent to the Euclidean distance, new, non Euclidean shapes appear for Voronoi diagrams, and we show a general construction of a nine-point Voronoi diagram with non Euclidean shape (Th.3).
Speculative prefetching
Authors: Y. Jégou, O. Temam
Venue: Proceedings of the 7th international conference on Supercomputing (1993)

A hardware prefetching mechanism named Speculative Prefetching is proposed. This scheme detects vector accesses issued by a load/store instruction and prefetches the corresponding data. The scheme requires no software add-on, and in some cases it is more powerful than software techniques for identifying regular accesses. The tradeoffs related to its hardware implementation are extensively discussed in order to finely tune the mechanism. Experiments show that average memory access time of regular codes is brought within 10% of optimum for processors with usual issue rates, while performance of irregular codes is little reduced though never degraded. The scheme performance is discussed over a wide range of parameters.
Exploring the status of the turnover and salary of information technology professionals in Singapore
Authors: Margaret Tan, Magid Igbaria
Venue: Proceedings of the 1993 conference on Computer personnel research (1993)

The rapid growth of technology in Singapore and the shortage of IT professionals had an impact on the country's competitiveness. The study shows that the turnover rate among IT professionals is still high, particularly among software professionals. There are large differences in the salaries of IT professionals. Salaries vary by job title (category), sector, working experience, nationality, education and in some jobs, by gender. The turnover rate and the number of job openings fell in 1990 and is expected to fall more in the near future. This study also reports that the main reasons for turnover are competition from other employers in remuneration and limited advancement opportunities. The managerial implications of these findings are discussed.