ppxscal/embedding_network huggingface dataset:
High-Order Schemes, Entropy Inequalities, and Nonclassical Shocks
Authors: Philippe G. LeFloch, Christian Rohde
Venue: SIAM Journal on Numerical Analysis (2000)

We are concerned with the approximation of undercompressive, regularization-sensitive, nonclassical solutions of hyperbolic systems of conservation laws by high-order accurate, conservative, and semidiscrete finite difference schemes. Nonclassical shock waves can be generated by diffusive and dispersive terms kept in balance. Particular attention is given here to a class of systems of conservation laws including the scalar equations and the system of nonlinear elasticity and to linear diffusion and dispersion in either the conservative or the entropy variables.First, we investigate the existence and the properties of entropy conservative schemes---a notion due to Tadmor [ Math. Comp., 49 (1987), pp. 91--103]. In particular we exhibit a new five-point scheme which is third-order accurate, at least.Second, we study a class of entropy stable and high-order accurate schemes satisfying a single cell entropy inequality. They are built from any high-order entropy conservative scheme by adding to it a mesh-independent, numerical viscosity, which preserves the order of accuracy of the base scheme. These schemes can only converge to solutions of the system of conservation laws satisfying the entropy inequality. These entropy stable schemes exhibit mild oscillations near shocks and, interestingly, may converge to classical or nonclassical entropy solutions, depending on the sign of their dispersion coefficient.Then, based on a third-order, entropy conservative scheme, we propose a general scheme for the numerical computation of nonclassical shocks. Importantly, our scheme satisfies a cell entropy inequality. Following Hayes and LeFloch [SIAM J. Numer. Anal., 35 (1998), pp. 2169--2194], we determine numerically the kinetic function which uniquely characterizes the dynamics of nonclassical shocks for each regularization of the conservation laws. Our results compare favorably with previous analytical and numerical results.Finally, we prove that there exists no fully discrete and entropy conservative scheme and we investigate the entropy stability of a class of fully discrete, Lax--Wendroff type schemes.
Source-to-Source Instrumentation for the Optimization of an Automatic Reading System
Authors: P. Pereira, L. Heutte, Y. Lecourtier
Venue: The Journal of Supercomputing (2001)

Recording address traces that occur during a program execution is a significant technique for computer performance analysis. This paper describes a software method for address tracing via the instrumentation of C based languages. All program transformations are performed at the language level. This approach, which differs from the usual methods, allows portable and flexible program instrumentation. This tool has been developed to make easier the memory optimization of LIRECh&egrave;ques, an automatic bank check reading system. Two applications of the tool are clearly identified: (i) data cache use optimization, (ii) dynamic memory use optimization.
Different bounds on the different Betti numbers of semi-algebraic sets
Authors: Saugata Basu
Venue: Proceedings of the seventeenth annual symposium on Computational geometry (2001)

A classic result in real algebraic geometry due to Oleinik-Petrovsky, Thom and Milnor, bounds the {\em topological complexity} (the sum of the Betti numbers) of basic semi-algebraic sets. This bound is tight as one can construct examples having that many connected components. However, till now no significantly better bounds were known on the individual higher Betti numbers.In this paper we prove separate bounds on the different Betti numbers of basic semi-algebraic sets, as well as arrangements of algebraic hypersurfaces. These are the first results in this direction.
Scheduling multi-task multi-agent systems
Authors: Rong Xie, Daniela Rus, Cliff Stein
Venue: Proceedings of the fifth international conference on Autonomous agents (2001)

We present a centralized and a distributed algorithms for scheduling multi-task agents in heterogeneous networks. Our centralized algorithm has an upper bound on the overall completion time and is used as a module in the distributed algorithm. Extensive simulations show promising results.
Automatically tuned collective communications
Authors: Sathish S. Vadhiyar, Graham E. Fagg, Jack Dongarra
Venue: Proceedings of the 2000 ACM/IEEE conference on Supercomputing (CDROM) (2000)

The performance of the MPI's collective communications is critical in most MPI-based applications. A general algorithm for a given collective communication operation may not give good performance on all systems due to the differences in architectures, network parameters and the storage capacity of the underlying MPI implementation. In this paper we discuss an approach in which the collective communications are tuned for a given system by conducting a series of experiments on the system. We also discuss a dynamic topology method that uses the tuned static topology shape, but re-orders the logical addresses to compensate for changing run time variations. A series of experiments were conducted comparing our tuned collective communication operations to various native vendor MPI implementations. The use of the tuned collective communications resulted in about 30 percent to 650 percent improvement in performance over the native MPI implementations.
An Efficient Optimal Normal Basis Type II Multiplier
Authors: Ç. K. Koç, B. Sunar
Venue: IEEE Transactions on Computers (2001)

This paper presents a new parallel multiplier for the Galois field $GF(2^m)$ whose elements are represented using the optimal normal basis of type II. The proposed multiplier requires $1.5(m^2-m)$ XOR gates, as compared to $2(m^2-m)$ XOR gates required by the Massey-Omura multiplier. The time complexities of the proposed and the Massey-Omura multipliers are similar.
Localization and identification of visual landmarks
Authors: Dan Knights, Jeff Lanza
Venue: Proceedings of the sixth annual CCSC northeastern conference on The journal of computing in small colleges (2001)

This project focused on designing and evaluating methods for reading barcodes on visual landmarks. Such landmarks have many applications, including visual tracking, servo-ing, and mobile robot navigation. Our goal was to improve a preliminary version of the barcode reader developed the previous summer in the Middlebury Robotics and Vision Lab.
DataTiles: a modular platform for mixed physical and graphical interactions
Authors: Jun Rekimoto, Brygg Ullmer, Haruo Oba
Venue: Proceedings of the SIGCHI conference on Human factors in computing systems (2001)

The DataTiles system integrates the benefits of two major interaction paradigms: graphical and physical user interfaces. Tagged transparent tiles are used as modular construction units. These tiles are augmented by dynamic graphical information when they are placed on a sensor-enhanced flat panel display. They can be used independently or can be combined into more complex configurations, similar to the way language can express complex concepts through a sequence of simple words. In this paper, we discuss our design principles for mixing physical and graphical interface techniques, and describe the system architecture and example applications of the DataTiles system.
A Block Algorithm for Matrix 1-Norm Estimation, with an Application to 1-Norm Pseudospectra
Authors: Nicholas J. Higham, Françoise Tisseur
Venue: SIAM Journal on Matrix Analysis and Applications (2000)

The matrix 1-norm estimation algorithm used in LAPACK and various other software libraries and packages has proved to be a valuable tool. However, it has the limitations that it offers the user no control over the accuracy and reliability of the estimate and that it is based on level 2 BLAS operations. A block generalization of the 1-norm power method underlying the estimator is derived here and developed into a practical algorithm applicable to both real and complex matrices. The algorithm works with n &times; t matrices, where t is a parameter. For t=1 the original algorithm is recovered, but with two improvements (one for real matrices and one for complex matrices). The accuracy and reliability of the estimates generally increase with t and the computational kernels are level 3 BLAS operations for t > 1. The last t-1 columns of the starting matrix are randomly chosen, giving the algorithm a statistical flavor. As a by-product of our investigations we identify a matrix for which the 1-norm power method takes the maximum number of iterations. As an application of the new estimator we show how it can be used to efficiently approximate 1-norm pseudospectra.
Reducing garbage collector cache misses
Authors: Hans-J. Boehm
Venue: ACM SIGPLAN Notices (2001)

Cache misses are currently a major factor in the cost of garbage collection, and we expect them to dominate in the future. Traditional garbage collection algorithms exhibit relatively little temporal locality; each live object in the heap is likely to be touched exactly once during each garbage collection. We measure two techniques for dealing with this issue: prefetch-on-grey, and lazy sweeping. The first of these is new in this context. Lazy sweeping has been in common use for a decade. It was introduced as a mechanism for reducing paging and pause times; we argue that it is also crucial for eliminating cache misses during the sweep phase. Our measurements are obtained in the context of a non-moving garbage collector. Fully copying garbage collection inherently requires more traffic through the cache, and thus probably also stands to benefit substantially from something like the prefetch-on-grey technique. Generational garbage collection may reduce the benefit of these techniques for some applications, but experiments with a non-moving generational collector suggest that they remain quite useful.
Task concurrency management methodology to schedule the MPEG4 IM1 player on a highly parallel processor platform
Authors: Chun Wong, Paul Marchal, Peng Yang
Venue: Proceedings of the ninth international symposium on Hardware/software codesign (2001)

This paper addresses the concurrent task management of complex multi-media systems, like the MPEG4 IM1 player, with emphasis on how to derive energy-cost vs time-budget curves through task scheduling on a multi-processor platform. Starting from the original &ldquo;standard&rdquo; specification, we extract the concurrency originally hidden by implementation decisions in a &ldquo;grey-box&rdquo; model. Then we have applied two high-level transformations on this model to improve the task-level concurrency. Finally, by scheduling the transformed task-graph, we have derived energy-cost vs time-budget curves. These curves will be used to get globally optimized design decisions when combining subsystems into one complete system or to be used by a dynamic scheduler. The results on the MPEG4 IM1 player confirm the validity of our assumptions and the usefulness of our approach.
Implementing Clenshaw-Curtis quadrature, II computing the cosine transformation
Authors: W. Morven Gentleman
Venue: Communications of the ACM (1972)

In a companion paper to this, &ldquo;I Methodology and Experiences,&rdquo; the automatic Clenshaw-Curtis quadrature scheme was described and how each quadrature formula used in the scheme requires a cosine transformation of the integrand values was shown. The high cost of these cosine transformations has been a serious drawback in using Clenshaw-Curtis quadrature. Two other problems related to the cosine transformation have also been troublesome. First, the conventional computation of the cosine transformation by recurrence relation is numerically unstable, particularly at the low frequencies which have the largest effect upon the integral. Second, in case the automatic scheme should require refinement of the sampling, storage is required to save the integrand values after the cosine transformation is computed. This second part of the paper shows how the cosine transformation can be computed by a modification of the fast Fourier transform and all three problems overcome. The modification is also applicable in other circumstances requiring cosine or sine transformations, such as polynomial interpolation through the Chebyshev points.
The role of computer system models in performance evaluation
Authors: Stephen R. Kimbleton
Venue: Communications of the ACM (1972)

Models constitute a useful means of investigating computer system performance. This paper examines the interrelationships between models and other methods for evaluating the performance of computer systems and establishes circumstances under which the use of a model is appropriate.
Mixed initiative interfaces for learning tasks: SMARTedit talks back
Authors: Steven A. Wolfman, Tessa Lau, Pedro Domingos, Daniel S. Weld
Venue: Proceedings of the 6th international conference on Intelligent user interfaces (2001)

Applications of machine learning can be viewed as teacher-student interactions in which the teacher provides training examples and the student learns a generalization of the training examples. One such application of great interest to the IUI community is adaptive user interfaces. In the traditional learning interface, the scope of teacher-student interactions consists solely of the teacher/user providing some number of training examples to the student/learner and testing the learned model on new examples. Active learning approaches go one step beyond the traditional interaction model and allow the student to propose new training examples that are then solved by the teacher. In this paper, we propose that interfaces for machine learning should even more closely resemble human teacher-student relationships. A teacher's time and attention are precious resources. An intelligent student must proactively contribute to the learning process, by reasoning about the quality of its knowledge, collaborating with the teacher, and suggesting new examples for her to solve. The paper describes a variety of rich interaction modes that enhance the learning process and presents a decision-theoretic framework, called DIAManD, for choosing the best interaction. We apply the framework to the SMARTedit programming by demonstration system and describe experimental validation and preliminary user feedback.
Models and areas for CS education research
Authors: John Stasko, Mark Guzdial, Mike Clancy, Nell Dale, Sally Fincher
Venue: ACM SIGCSE Bulletin (2001)

We hope to alert attendees of this panel to a number of aspects of CS education research: bull; previous work that provides good models for future research; bull; current projects and results; bull; areas that deserve more inquiry; bull; questions for which research is unlikely at the moment to yield useful information.The panel is aimed at people who don't need to be convinced about the value of CS education research, but who perhaps are unfamiliar with what's happening or how they might get involved themselves.
Genetic Programming Prediction of Stock Prices
Authors: M. A. Kaboudan
Venue: Computational Economics (2000)

Based on predictions of stock-prices using genetic programming (or GP), a possibly profitable trading strategy is proposed. A metric quantifying the probability that a specific time series is GP-predictable is presented first. It is used to show that stock prices are predictable. GP then evolves regression models that produce reasonable one-day-ahead forecasts only. This limited ability led to the development of a single day-trading strategy (SDTS) in which trading decisions are based on GP-forecasts of daily highest and lowest stock prices. SDTS executed for fifty consecutive trading days of six stocks yielded relatively high returns on investment.
Enhancing Jini for use across non-multicastable networks
Authors: Ahmed Al-Theneyan, Piyush Mehrotra, Mohammed Zubair
Venue: ACM SIGOPS Operating Systems Review (2001)

Distributed heterogeneous systems are being increasingly used to execute a variety of large size simulation and computational problems. Resource management is one of the most important issues in building such systems. Recently, Sun introduced the Jini connection technology for building plug-and-play networks of resources. Jini relies on multicasting across the network for its internal protocols. However, in a distributed environment, such as the one under consideration here, multicasting may not be supported across the subnets for various reasons. In this paper we describe enhancements to Jini required to use it for building a middleware resource management system in a distributed environment that does not support multicasting. In particular, we introduce a lightweight service, called the Tunneling Service, which tunnels multicast messages across the subnets. We have implemented our mechanism and used it to successfully tunnel messages between subnets in a single domain and also between different domains. In this paper we describe our design choices and our implementation of the system.
Face and Eye Detection by CNN Algorithms
Authors: David Balya, Tamás Roska
Venue: Journal of VLSI Signal Processing Systems (1999)

A novel approach to critical parts of face detection problems is given, based on analogic cellular neural network (CNN) algorithms. The proposed CNN algorithms find and help to normalize human faces effectively while their time requirement is a fraction of the previously used methods. The algorithm starts with the detection of heads on color pictures using deviations in color and structure of the human face and that of the background. By normalizing the distance and position of the reference points, all faces should be transformed into the same size and position. For normalization, eyes serve as points of reference. Other CNN algorithm finds the eyes on any grayscale image by searching characteristic features of the eyes and eye sockets. Tests made on a standard database show that the algorithm works very fast and it is reliable.
A pre-serialization transaction management technique for mobile multidatabases
Venue: Mobile Networks and Applications (2000)

Rapid advances in hardware and wireless communication technology have made the concept of mobile computing a reality. Thus, evolving database technology needs to address the requirements of the future mobile user. The frequent disconnection and migration of the mobile user violate underlying presumptions about connectivity that exist in wired database systems and introduce new issues that affect transaction management. In this paper, we present the Pre&dash;Serialization &lpar;PS&rpar; transaction management technique for the mobile multidatabase environment. This technique addresses disconnection and migration and enforces a range of atomicity and isolation criteria. We also develop an analytical model to compare the performance of the PS technique to that of the Kangaroo model.
Legal implications of computer use
Authors: Roy N. Freed
Venue: Communications of the ACM (1962)

This paper points out a variety of ways computer systems used in business and industry can be involved in legal entanglements and suggests that computer specialists have a responsibility to call for assistance in forestalling or minimizing those entanglements during the planning stage. Techniques are suggested for making legal clearance effective with the least burden on the new technology and for achieving a favorable legal climate for it generally. Computer specialists also are alerted to potential opportunities to interpret to lawyers the technical aspects of computer systems involved in legal situations.
Teaching a first-level programming course to management students: a flexible approach
Authors: Kay Bryant
Venue: Proceedings of the Australasian conference on Computing education (2000)

Many universities are providing a flexible format in their teaching programmes. A wealth of literature exist on the various methods that many researchers have employed in providing a flexible learning environment for students. However, much of the current research focuses on instructional design and learner characteristics in general rather than on specific course areas. This study explorers the use of a flexible approach to teaching management students the rudiments of programming in a business degree. The results of this study indicate student performance has been enhanced through the use of the flexible learning approach and that they believe Web-based technologies provide an effective learning environment. Further research is being conducted to extend these findings to other student cohorts.
A rapid development process with UML
Authors: Giuliano Armano, Michele Marchesi
Venue: ACM SIGAPP Applied Computing Review (2000)

Since "design-oriented" life-cycles came to their maturity, dramatic changes have been introduced as far as programming tools and computer hardware are concerned. Such changes made it possible to develop applications focusing on refactoring rather than on analysis and design. The underlying hypothesis is that by adopting suitable tools and target languages, refactoring would possibly cost less than the overhead introduced by modern A amp;D techniques. Recently, extreme programming has been proposed as an alternative to a "design-oriented" life-cycle.In this paper we describe a software application developed using a software life-cycle that basically follows the guidelines suggested by extreme programming. Such an approach requires highly expressive programming languages and powerful CASE tools. UML has been selected as the underlying modeling language throughout the whole process, for it incorporates well-known diagrams for describing a software application from different perspectives. Smalltalk has been selected as target language, as it allows fast prototyping and early delivery. We claim that, for small and medium-sized projects, a life-cycle based on refactoring and supported by suitable languages and tools allows team productivity to be greatly enhanced.
Negative and zero subscripts in Fortran II programming for the IBM 1620
Authors: M. J. Garber
Venue: Communications of the ACM (1965)

The requirement that subscripts be unsigned integers creates some inconvenience in FORTRAN programming for summarization of completed questionnaires in which the responses may be scaled beginning at zero.
Rough and ready error estimates in Gaussian integration of analytic functions
Authors: Philip Rabinowitz
Venue: Communications of the ACM (1969)

Two expressions are derived for use in estimating the error in the numerical integration of analytic functions in terms of the maximum absolute value of the function in an appropriate region of regularity. These expressions are then specialized to the case of Gaussian integration rules, and the resulting error estimates are compared with those obtained by the use of tables of error coefficients.
Structured data structures
Authors: Ben Shneiderman, Peter Scheuermann
Venue: Communications of the ACM (1974)

Programming systems which permit arbitrary linked list structures enable the user to create complicated structures without sufficient protection. Deletions can result in unreachable data elements, and there is no guarantee that additions will be performed properly. To remedy this situation, this paper proposes a Data Structure Description and Manipulation Language which provides for the creation of a restricted class of data structures but ensures the correctness of the program. This is accomplished by an explicit structure declaration facility, a restriction on the permissible operations, and execution-time checks.
American standard code for information interchange
Authors: S. Gorn, R. W. Bemer, J. Green
Venue: Communications of the ACM (1963)

There was the germ of an idea in two previous papers [1, 2] which no one seems to have picked up in almost five years. For certain functions it seems desirable to transform the argument to a short range symmetric about 1.0. I will give examples of this usage for the square root and logarithm function for both binary and decimal machines.