ppxscal/embedding_network huggingface dataset:
Discrete-event simulation on the World Wide Web using Java
Authors: Arnold H. Buss, Kirk A. Stork
Venue: Proceedings of the 28th conference on Winter simulation (1996)

This paper introduces Simkit, a small set of Java classes for creating discrete event simulation models. Simkit may be used to either implement stand-alone models or Web page applets. Exploiting network capabilities of Java, the lingua franca of the World Wide Web (WWW), Simkit models can easily be implemented as applets and executed in a Web browser. Java's graphical capabilities enable the rapid development of intuitive user interfaces. Java's use of in terpreted bytecodes, while imposing a performance penalty, enable development of platform-independent models. The language's inherent internet-awareness make other possibilities, such as distributed simulation, much easier to implement.
Harmonnic and Intermodulation Performance of Op-Amp Power-Supply Current and the Dual Translinear Loop
Authors: Muhammad Taher Abuelma’atti, Sofian Mustafa Abed
Venue: Analog Integrated Circuits and Signal Processing (1998)

The nonlinear behavior of the op-amp power supply current and the dual translinear loop are analyzed. Closed-form expressions are obtained for the harmonic and intermodulation components resulting from a multisinusoidal input signal. These expressions can be used to predict the limiting values of the input current for a prespecified tolerable distortion percentage.
Performance analysis of a system of communicating processes
Authors: Sujit Dey, Surendra Bommu
Venue: Proceedings of the 1997 IEEE/ACM international conference on Computer-aided design (1997)

Efficient exploration of the system design space necessitates fast and accurate performance estimation as opposed to the computationally prohibitive alternative of exhaustive simulation. The paper addresses the issue of worst case performance analysis of a system described as a set of concurrent communicating processes. We show that the synchronization overhead associated with inter process communication can contribute significantly to the overall system performance. Application of existing performance analysis techniques, which target single process descriptions, lead to inaccurate performance estimates as the synchronization overhead is not accounted for. We present PERC, a fast and accurate worst case performance analysis technique which analyzes inter process communication, and accounts for synchronization overhead while computing the worst case performance estimate of a given system implementation. Application of PERC to example systems described as multiple communicating processes shows the ability of the proposed method to accurately estimate the worst case performance of the system implementation.
Challenges in type systems research
Authors: Martin Odersky
Venue: ACM SIGPLAN Notices (1997)

Type systems are one backbones of programming language design and implementation. Current research addresses questions in fields as diverse as mathematical logic, program analysis, and human factors engineering. Some of the future challenges for the field are: increasing the expressiveness of typed programming languages, broadening the information carried by types, and making type systems amenable to user definition and customization.
On the perfect accuracy of an approximate subscript analysis test
Authors: David Klappholz, Kleanthis Psarris, Xiangyun Kong
Venue: Proceedings of the 4th international conference on Supercomputing (1990)

The Banerjee test is commonly considered to be the more accurate of the two major approximate data dependence tests used in automatic vectorization/parallelization of loops, the other being the GCD test. From its derivation, however, there is no simple explanation of why the Banerjee test should be nearly as accurate as it is given credit for. We present a set of sufficient conditions for the Banerjee test's accuracy, and explain its perceived accuracy in actual practice by proving that under circumstances which occur extremely frequently in actual code, the Banerjee test is, in fact, not approximate, but perfectly accurate.
Breadth-first rollback in spatially explicit simulations
Authors: Ewa Beelman, Boleslaw K. Szymanski
Venue: Proceedings of the eleventh workshop on Parallel and distributed simulation (1997)

The efficiency of parallel discrete event simulations that use the optimistic protocol is strongly dependent on the overhead incurred by rollbacks. The paper introduces a novel approach to rollback processing which limits the number of events rolled back as a result of a straggler or antimessage. The method, called breadth-first rollback (BFR), is suitable for spatially explicit problems where the space is discretized and distributed among processes and simulation objects move freely in the space. BFR uses incremental state saving, allowing the recovery of causal relationships between events during rollback. These relationships are then used to determine which events need to be rolled back. The results demonstrate an almost linear speedup-a dramatic improvement over the traditional approach to rollback processing.
Simulating the (HE3/HE3/S):(PRP/ &infin; / &infin;) queuing model for a maintenance problem
Authors: Weixing Zhang, Way Kuo, Victor M. Tamashunas
Venue: Proceedings of the 17th conference on Winter simulation (1985)

A new queuing model (HE3/HE3/S):(PRP/&infin;/&infin;), in which both the interarrival times and the service times follow the hyperexponential distributions with three branches, has been justified for a machine maintenance problem. Analysis of the problem is based on the data obtained from a large and complex manufacturing system. The GPSS model is constructed so that it collects desired queuing statistics under alternative conditions of a different number of servers. The essential purpose of this study is to model a priority queuing problem with multi-servers. The GPSS design can apply to waiting line problems where random variables of interest have large variations.
Object-oriented practice in 1998 (panel): does it help or hinder collaboration?
Authors: John Artim, Charlie Bridgeford, Lillian Christman, James Coplien, Mary Beth Rosson, Stanley Taylor, Rebecca Wirfs-Brock
Venue: ACM SIGPLAN Notices (1998)

Groups of people working in concert perform most commercial, industrial or in-house software development. These groups are often quite diverse. This panel brings together object-oriented consultants and developers as well as practitioners and researchers interested in human factors and user-centered design, project management and technical writing. The panel will address the question, "To successfully complete today's projects, does object-oriented development as practiced today do an adequate job of supporting ALL of the participants who must collaborate?"
I/O scheduling for digital continuous media
Authors: Deepak R. Kenchammana-Hosekote, Jaideep Srivastava
Venue: Multimedia Systems (1997)

A growing set of applications require access to digital video and audio. In order to provide playback of such continuous media (CM), scheduling strategies for CM data servers (<b>CMS</b>) are necessary. In some domains, particularly defense and industrial process control, the timing requirements of these applications are strict and essential to their correct operation. In this paper we develop a scheduling strategy for multiple access to a <b>CMS</b> such that the timing guarantees are maintained at all times. First, we develop a scheduling strategy for the steady state, i.e., when there are no changes in playback rate or operation. We derive an optimal <i>Batched SCAN</i> <b>(BSCAN)</b> algorithm that requires minimum buffer space to schedule concurrent accesses. The scheduling strategy incorporates two key constraints: (1) data fetches from the storage system are assumed to be in integral multiples of the block size, and (2) playback guarantees are ensured for frame-oriented streams when each frame can span multiple blocks. We discuss modifications to the scheduling strategy to handle compressed data like motion-JPEG and MPEG.Second, we develop techniques to handle dynamic changes brought about by <i>VCR</i>-like operations executed by applications. We define a suite of primitive <i>VCR</i>-like operations that can be executed. We show that an unregulated change in the <b>BSCAN</b> schedule, in response to <i>VCR</i>-like operations, will affect playback guarantees. We develop two general techniques to ensure playback guarantees while responding to <i>VCR</i>-like operations: passive and active accumulation. Using user response time as a metric we show that active accumulation algorithms outperform passive accumulation algorithms. An optimal response-time algorithm in a class of active accumulation strategies is derived. The results presented here are validated by extensive simulation studies.
Highly Scalable Parallel Algorithms for Sparse Matrix Factorization
Authors: Anshul Gupta, George Karypis, Vipin Kumar
Venue: IEEE Transactions on Parallel and Distributed Systems (1997)

In this paper, we describe scalable parallel algorithms for symmetric sparse matrix factorization, analyze their performance and scalability, and present experimental results for up to 1,024 processors on a Cray T3D parallel computer. Through our analysis and experimental results, we demonstrate that our algorithms substantially improve the state of the art in parallel direct solution of sparse linear systems¿both in terms of scalability and overall performance. It is a well known fact that dense matrix factorization scales well and can be implemented efficiently on parallel computers. In this paper, we present the first algorithms to factor a wide class of sparse matrices (including those arising from two- and three-dimensional finite element problems) that are asymptotically as scalable as dense matrix factorization algorithms on a variety of parallel architectures. Our algorithms incur less communication overhead and are more scalable than any previously known parallel formulation of sparse matrix factorization. Although, in this paper, we discuss Cholesky factorization of symmetric positive definite matrices, the algorithms can be adapted for solving sparse linear least squares problems and for Gaussian elimination of diagonally dominant matrices that are almost symmetric in structure. An implementation of one of our sparse Cholesky factorization algorithms delivers up to 20 GFlops on a Cray T3D for medium-size structural engineering and linear programming problems. To the best of our knowledge, this is the highest performance ever obtained for sparse Cholesky factorization on any supercomputer.
Comments on "Property-Based Software Engineering Measurement: Refining the Additivity Properties"
Authors: Geert Poels, Guido Dedene
Venue: IEEE Transactions on Software Engineering (1997)

The recently published measure property set of Briand, Morasca, and Basili [1] establishes the foundation of a real software measurement theory. Unfortunately, a number of inconsistencies related to additivity properties might hinder its acceptance and further elaboration. In this paper, it is shown how to remove the ambiguity in the property definitions.
Using Forward Accumulation for Automatic Differentiation of Implicitly-Defined Functions
Authors: M. C. Bartholomew-Biggs
Venue: Computational Optimization and Applications (1998)

This paper deals with the calculation of partial derivatives (w.r.t. the independent variables, x) of a vec of dependent variables y which satisfy a system of nonlinear equationsg(u(x), y) = 0 . A number of authors have suggested that the forward accumulation method of automatic differentiation can be applied to a suitable iterative scheme for solving the nonlinear system with a view to giving simultaneous convergence both to the correct value y and also to its Jacobian matrixy_x . It is known, however, that convergence of the derivatives may not occur at the same rate as the convergence of they values. In this paper we avoid both the difficulty and the potential cost of iterating the gradient part of the calculation to sufficient accuracy. We do this by observing that forward accumulation need only be applied to the functions g after the dependent variables, y, have been computed in standard real arithmetic usin g any appropriate method. This so-called Post-Differentiation (PD) technique is shown, on a number of examples, to have an advantage in terms of both accuracy and speed over approaches where forward accumulation is applied over the entire iterative process. Moreover, the PD technique can be implemented in such a way as to provide a friendly interface for non-specialist users.
Optimal On-Line Search and Sublinear Time Update in String Matching
Authors: Paolo Ferragina, Roberto Grossi
Venue: SIAM Journal on Computing (1998)

This paper investigates the problem of searching on-line for the occurrences (occ) of an arbitrary pattern of length p in a text of length n subjected to some updates after its preprocessing. Each text update consists of inserting or deleting an arbitrary string of length y. We present the first dynamic algorithm that achieves optimal query time, i.e., $\Theta(p+occ)$, sublinear time per update, i.e., $O(\sqrt{n} + y)$, and optimal space, i.e., $\Theta(n)$, in the worst case. As a result, our algorithm obtains the same query time and space usage of suffix trees [McCreight, J. Assoc. Comput. Mach., 23 (1976), pp. 262--272] while improving their O(n + y) update performance.
Ownership types for flexible alias protection
Authors: David G. Clarke John M. Potter, James Noble
Venue: ACM SIGPLAN Notices (1998)

Object-oriented programming languages allow inter-object aliasing. Although necessary to construct linked data structures and networks of interacting objects, aliasing is problematic in that an aggregate object's state can change via an alias to one of its components, without the aggregate being aware of any aliasing.Ownership types form a static type system that indicates object ownership. This provides a flexible mechanism to limit the visibility of object references and restrict access paths to objects, thus controlling a system's dynamic topology. The type system is shown to be sound, and the specific aliasing properties that a system's object graph satisfies are formulated and proven invariant for well-typed programs.
Simulation of a pyramid processor
Authors: Duane R. Ball, Gerard C. Blais, David Schaefer, Gregory Wilcox, R. Neil Wagoner
Venue: Proceedings of the 17th conference on Winter simulation (1985)

This paper describes a simulation model of the MPP Pyramid [1] that has been constructed at the George Mason University. This model has been designed to facilitate experiments in processor control and in instruction set design.
Reducing garbage in Java
Authors: C. E. McDowell
Venue: ACM SIGPLAN Notices (1998)

One of the important advantages of Java, from a programmers prospective, is the use of garbage collection. One aspect of memory management in Java is that all objects are created on a garbage collected heap. Only primitive types, mostly numeric types and references to objects, are allocated on the runtime stack. We speculated that a significant number of objects behaved like traditional automatic variables, that are normally allocated on the runtime stack. We instrumented a Java virtual machine to test this hypothesis. The percentage of objects that could have been allocated on a stack instead of on the heap ranged from zero to possibly as high as 56%, but were generally in the 5--15% range.
System calls and interrupt vectors in an operating systems course
Authors: Mark A. Holliday
Venue: ACM SIGCSE Bulletin (1997)

The introductory operating systems course has a tendency to appear to the student as a disparate collection of topics such as synchronization primitives, process scheduling algorithms, and page replacement policies. We describe a sequence of material to cover early in the operating systems course that prevents this tendency by clarifying the goal of the course and by providing a framework for understanding how the later course material is used in kernel design. The material centers around two concepts. First is the importance of the abstraction provided by the system call interface, that the kernel is the implementation of that interface, and the analogy with the instruction set interface the student has already encountered. Second is how the interrupt vector mechanism in a broad sense is central to how the kernel functions and underpins the actual implementation of many of the other topics in the course. Illustration through code from a real operating system kernel is a key feature of how this sequence makes clear the workings of an operating system.
A Fast Stable Solver for Nonsymmetric Toeplitz and Quasi-Toeplitz Systems of Linear Equations
Authors: S. Chandrasekaran, Ali H. Sayed
Venue: SIAM Journal on Matrix Analysis and Applications (1998)

We derive a stable and fast solver for nonsymmetric linear systems of equations with shift structured coefficient matrices (e.g., Toeplitz, quasi-Toeplitz, and product of two Toeplitz matrices). The algorithm is based on a modified fast QR factorization of the coefficient matrix and relies on a stabilized version of the generalized Schur algorithm for matrices with displacement structure. All computations can be done in O(n2) operations, where n is the matrix dimension, and the algorithm is backward stable.
Scattered Data Interpolation Using C2 Supersplines of Degree Six
Authors: Ming-Jun Lai, Larry L. Schumaker
Venue: SIAM Journal on Numerical Analysis (1997)

We show how C2 supersplines of degree six can be used to interpolate Hermite data at the vertices of a quadrangulation. We also present error bounds that show that our method has full approximation order seven, and compare its efficiency with other C2interpolation methods in the literature.
MPEG-4: an object-based multimedia coding standard supporting mobile applications
Authors: Atul Puri, Alexandros Eleftheriadis
Venue: Mobile Networks and Applications (1998)

The ISO MPEG committee, after successful completion of the MPEG-1 and the MPEG-2 standards is currently working on MPEG-4, the third MPEG standard. Originally, MPEG-4 was conceived to be a standard for coding of limited complexity audio-visual scenes at very low bit-rates; however, in July 1994, its scope was expanded to include coding of scenes as a collection of individual audio-visual objects and enabling a range of advanced functionalities not supported by other standards. One of the key functionalities supported by MPEG-4 is robustness in error prone environments. In general, the MPEG-4 standard provides solutions for coding of natural or synthetic video and audio, as well as a system for multiplex/demultiplex and description of scenes in a truly flexible manner. With focus on the mobile multimedia functionality, we present an overview of the current status as well as the details of the MPEG-4 coding standard. We also discuss profiles, a mechanism used for partitioning MPEG-4 into realizable subsets. Finally, plans for testing and verification of current MPEG-4 (Version 1) standard, ongoing work for MPEG-4 Version 2, as well as directions for MPEG-7, the next MPEG standard, are briefly discussed.
Building real-time imprecise computations in Ada
Authors: Gary J. Gregory, Kwei-Jay Lin
Venue: Proceedings of the conference on TRI-ADA '90 (1990)

The model of imprecise computation is an effective way to structure programs that must always meet deadlines in real-time systems. Under severe time constraints, an imprecise computation may return an imprecise, though correct value. In this way, timing faults can be avoided. In this paper, we describe two implementations of an imprecise computation package in Ada. We have also studied their performance differences under different system and programming environments. Finally, we present our experience in implementing real-time applications using Ada.
Decomposition in Real-Time Safety-Critical Systems
Authors: Paul Mukherjee, Victoria Stavridou
Venue: Real-Time Systems (1998)

Existing formal techniques for the development of software for use in safety-critical systems do not adequately address non-functional system requirements such as those involving timing. In this paper we describe a formal development method in which specifications may be decomposed into unexceptional programs whilst preserving the functional and timing requirements of the specification. We illustrate the method with a speed monitoring example.
Preconditioning of Block Toeplitz Matrices by Sine Transforms
Authors: Fabio Di Benedetto
Venue: SIAM Journal on Scientific Computing (1997)

The iterative solution of a block Toeplitz linear system by the conjugate gradient method is analyzed, the preconditioning step being solved by means of a discrete sine transform. Convergence properties are established and compared to the behavior of the block circulant preconditioner recently proposed in the literature. As in the scalar case, the new approach takes advantage if the system is ill conditioned.
Pitfalls in Parameter Estimation for Delay Differential Equations
Authors: Christopher T. H. Baker, Christopher A. H. Paul
Venue: SIAM Journal on Scientific Computing (1997)

Given a set of data $\{U(\gamma_{i}) \approx u(\gamma_{i};\sfp^{\star})\}$ corresponding to the {\em delay differential equation} \vspace{-3pt} $$ \begin{array}{rcll} u'(t;\sfp) &=& f(t,u(t;\sfp),u(\alpha(t;\sfp);\sfp);\sfp) & \hbox{for } t \ge t_{0}(\sfp),\\ u(t;\sfp) &=& \Psi(t;\sfp) & \hbox{for } t \le t_{0}(\sfp), \end{array} $$ the basic problem addressed here is that of calculating the vector $\sfp^{\star} \in {\blackboardd R}^{n}$. (We also consider neutral differential equations.) Most approaches to parameter estimation calculate $\sfp^{\star}$ by minimizing a suitable objective function that is assumed by the minimization algorithm to be sufficiently smooth. In this paper, we use the derivative discontinuity tracking theory for delay differential equations to analyze how jumps can arise in the derivatives of a natural objective function. These jumps can occur when estimating parameters in lag functions and estimating the position of the initial point, and as such are not expected to occur in parameter estimation problems for ordinary differential equations.
A Penalized Finite-Element Method for a Compressible Stokes System
Authors: R. Bruce Kellogg, Biyue Liu
Venue: SIAM Journal on Numerical Analysis (1997)

The linearized steady-state compressible viscous Navier--Stokes equations with constant coefficients are considered in this paper. A penalty method has been applied to the continuity equation. A finite-element formulation is constructed by applying a streamline diffusion method to the penalized continuity equation and applying the usual Galerkin method to the momentum equations. The resulting finite-element formulation is uniquely solvable without requiring any compatibility condition on the subspaces for velocity and pressure. An error estimate is obtained.
Generalized Controlled Invariance for Nonlinear Systems
Authors: H. J. C. Huijberts, C. H. Moog, R. Andiarti
Venue: SIAM Journal on Control and Optimization (1997)

A general setting is developed which describes controlled invariance for nonlinear control systems and which incorporates the previous approaches dealing with controlled invariant (co -) distributions. A special class of controlled invariant subspaces, called controllability cospaces, is introduced. These geometric notions are shown to be useful for deriving a (geometric) solution to the dynamic disturbance decoupling problem and for characterizing the so-called fixed dynamics for noninteracting control. These fixed dynamics are a central issue in studying noninteracting control with stability. The class of quasi-static state feedbacks is used.