ppxscal/embedding_network huggingface dataset:
Developing computational science curricula: the EarthVision experience
Authors: Ralph K. Coppola, Eva Erdosne Toth
Venue: Proceedings of the 1995 ACM/IEEE conference on Supercomputing (CDROM) (1995)

Technology is used to empower students to go beyond traditional limitations. EarthVision provides the opportunity to participate in an authentic research environment enables the students to develop a sense of self worth and esteem established in the context of a phased curriculum, bringing together experts in a variety of disciplines. New techniques such as modeling and scientific visualization are employed to expand the types of phenomena which are possible to examine at a high school level. The use of concept strands going from simple elements to complicated representations helps to move the teacher/student teams from a highly structured learning environment to one that is highly independent. The scientific method, which employs validation throughout the computational science process, brings rigor and integrity which stimulates skill development needed for the development of autonomy. The result is significant cognitive development coupled with a positive affective orientation.
Towards an effective calculus for object query languages
Authors: Leonidas Fegaras, David Maier
Venue: Proceedings of the 1995 ACM SIGMOD international conference on Management of data (1995)

We define a standard of effectiveness for a database calculus relative to a query language. Effectiveness judges suitability to serve as a processing framework for the query language, and comprises aspects of coverage, manipulability and efficient evaluation. We present the monoid calculus, and argue its effectiveness for object-oriented query languages, exemplified by OQL of ODMG-93. The monoid calculus readily captures such features as multiple collection types, aggregations, arbitrary composition of type constructors and nested query expressions. We also show how to extend the monoid calculus to deal with vectors and arrays in more expressive ways than current query languages do, and illustrate how it can handle identity and updates.
Rejection-inversion to generate variates from monotone discrete distributions
Authors: W. Hörmann, G. Derflinger
Venue: ACM Transactions on Modeling and Computer Simulation (TOMACS) (1996)

For discrete distributions a variant of reject from a continuous hat function is presented. The main advantage of the new method, called rejection-inversion, is that no extra uniform random number to decide between acceptance and rejection is required, which means that the expected number of uniform variates required is halved. Using rejection-inversion and a squeeze, a simple universal method for a large class of monotone discrete distributions is developed. It can be used to generate variates from the tails of most standard discrete distributions. Rejection-inversion applied to the Zipf (or zeta) distribution results in algorithms that are short and simple and at least twice as fast as the fastest methods suggested in the literature.
Leave-in-Time: a new service discipline for real-time communications in a packet-switching network
Authors: Norival R. Figueira, Joseph Pasquale
Venue: Proceedings of the conference on Applications, technologies, architectures, and protocols for computer communication (1995)

Leave-in-Time is a new rate-based service discipline for packet-switching nodes in a connection-oriented data network. Leave-in-Time provides sessions with upper bounds on end-to-end delay, delay jitter, buffer space requirements, and an upper bound on the probability distribution of end-to-end delays. A Leave-in-Time session's guarantees are completely determined by the dynamic traffic behavior of that session, without influence from other sessions. This results in the desirable property that these guarantees are expressed as functions derivable simply from a single fixed-rate server (with rate equal to the session's reserved rate) serving only that session. Leave-in-Time has a non-work-conserving mode of operation for sessions desiring low end-to-end delay jitter. Finally, Leave-in-Time supports the notion of delay shifting, whereby the delay bounds of some sessions may be decreased at the expense of increasing those of other sessions. We present a set of admission control algorithms which support the ability to do delay shifting in a systematic way.
Repository mirroring
Authors: Eric Grosse
Venue: ACM Transactions on Mathematical Software (TOMS) (1995)

Distributed administration of network repositories demands a low-overhead procedure for cooperating repositories around the world to ensure they hold identical contents. Netlib has adopted some refinements on the widespread scheme of anonymous ftp and s-R. Checksum files and two small C programs give an easily maintained system that copes with communication breakdowns and subtle changes in repository contents. The packaging of these C programs inside a shell pipeline provides an explicit command stream that can readily be checked before execution. Protecting files, keeping logs, and so forth become effortless and reliable. The same tools, applied on a smaller scale, allow more people to participate in the editorial work of maintaining a high-quality repository, by eliminating the need for directly manipulating files at remote sites.
NIFDY: a low overhead, high throughput network interface
Authors: Timothy Callahan, Seth Copen Goldstein
Venue: Proceedings of the 22nd annual international symposium on Computer architecture (1995)

In this paper we present NIFDY, a network interface that uses admission control to reduce congestion and ensures that packets are received by a processor in the order in which they were sent, even if the underlying network delivers the packets out of order. The basic idea behind NIFDY is that each processor is allowed to have at most one outstanding packet to any other processor unless the destination processor has granted the sender the right to send multiple unacknowledged packets. Further, there is a low upper limit on the number of outstanding packets to all processors.We present results from simulations of a variety of networks (meshes, tori, butterflies, and fat trees) and traffic patterns to verify NIFDY's efficacy. Our simulations show that NIFDY increases throughput and decreases overhead. The utility of NIFDY increases as a network's bisection bandwidth decreases. When combined with the increased payload allowed by in-order delivery NIFDY increases total bandwidth delivered for all networks. The resources needed to implement NIFDY are small and constant with respect to network size.
A communication and cooperation scheme to support distributed knowledge-based systems
Authors: Gyutae Baek
Venue:  (1995)

A new perspective of the validation problem for simulation models is formulated in this article. The approach is knowledge-based and focuses on behavioral validation. It has the important feature of providing a basis for the development of a software environment that can automate the validation activity. Discrete, continuous and combined simulation models can be treated in a uniform manner. The key element of the approach is a validation knowledge base (VKB). This is developed as three disjoint sets of relationships among the input and output variables of the simulation model. These relationships serve to capture all aspects of expected behavior of the simulation model. A simple characterization of model behavior is presented which provides the basis for specifying the relationships from which the VKB is constructed. The utilization of all the information in the VKB in an efficient way is an important subgoal of our system architecture. This requirement gives rise to an experiment design problem. This problem is carefully formulated and examined within the framework of the behavior characterizations that exist in the VKB. In particular, a basis for its solution is established in a constraint set framework by carrying out a transformation on the relationships within the VKB. The constraint set context for the problem has the advantage of providing an environment which not only facilitates analysis but also enables the application of a variety of solution techniques.
A note on probabilistically verifying integer and polynomial products
Authors: Michael Kaminski
Venue: Journal of the ACM (JACM) (1989)

Probabilistic algorithms are presented for testing the result of the product of two n-bit integers in O(n) bit operations and for testing the result of the product of two polynomials of degree n over any integral domain in 4n + o(n) algebraic operations with the error probability o(l/n1-&egr;) for any &egr; > 0. The last algorithm does not depend on the constants of the underlying domain.
Invariants of Six Points and Projective Reconstruction From Three Uncalibrated Images
Authors: Long Quan
Venue: IEEE Transactions on Pattern Analysis and Machine Intelligence (1995)

There are three projective invariants of a set of six points in general position in space. It is well known that these invariants cannot be recovered from one image, however an invariant relationship does exist between space invariants and image invariants. This invariant relationship is first derived for a single image. Then this invariant relationship is used to derive the space invariants, when multiple images are available.This paper establishes that the minimum number of images for computing these invariants is three, and the computation of invariants of six points from three images can have as many as three solutions. Algorithms are presented for computing these invariants in closed form.The accuracy and stability with respect to image noise, selection of the triplets of images and distance between viewing positions are studied both through real and simulated images.Applications of these invariants are also presented. Both the results of Faugeras [1] and Hartley et al. [2] for projective reconstruction and Sturm¿s method [3] for epipolar geometry determination from two uncalibrated images with at least seven points are extended to the case of three uncalibrated images with only six points.
On a QR-like Algorithm for Some StructuredEigenvalue Problems
Authors: A. George, Kh. D. Ikramov, E. V. Matushkina, W.-P. Tang
Venue: SIAM Journal on Matrix Analysis and Applications (1995)

In this paper, a QR-like algorithm, called the con-QR algorithm, for computing the Youla form of a general complex matrix is presented. The Youla form is an analog of the Schur form where unitary congruences instead of unitary similarities are employed. We introduce a set of invariants of a unitary congruence transformation which are called coneigenvalues, and discuss their condition. Finally, the practical value of the Youla form is discussed.
Horizontal Principal Structure of Layered Mixed Matrices: Decomposition of Discrete Systems by Design-Variable Selections
Authors: Satoru Iwata, Kazuo Murota
Venue: SIAM Journal on Discrete Mathematics (1996)

A matrix $A=\bigl(\begin{smallmatrix}Q\\T\end{smallmatrix}\bigr)$ is called a layered mixed matrix (LM-matrix) if the set of nonzero entries of $T$ is algebraically independent over the field to which the entries of $Q$ belong. This concept has been proposed as a mathematical tool for describing discrete physical/engineering systems. It is known that there uniquely exists a finest block-triangularization of an LM-matrix, which is called the combinatorial canonical form (CCF). In this paper, associated with an LM-matrix we introduce a new submodular function $q$ characterizing its rank. This submodular function $q$ is defined on a modular lattice. It will be shown that the principal structure of $q$ gives the coarsest decomposition of the row side that is finer than any decomposition induced by the CCF of the submatrix consisting of a base of the column vectors of $A$. This gives a best possible bound on the extent to which the whole system can be decomposed by a suitable choice of design variables.
Hierarchical Cubic Networks
Authors: Kanad Ghose, Kiran R. Desai
Venue: IEEE Transactions on Parallel and Distributed Systems (1995)

We introduce a new interconnection network for large-scale distributed memory multiprocessors called the Hierarchical Cubic Network (HCN). We establish that the number of routing steps needed by several data parallel applications running on a HCN-based system and a hypercube-based system are about identical. Further, hypercube connections can be emulated on the HCN in constant time. Simulation of uniform and localized traffic patterns reveal that the normalized average internode distances in a HCN are better than in a comparable hypercube. Additionally, the HCN also has about three-fourths the diameter of a comparable hypercube, although it uses about half as many links per node¿a fact that has positive ramifications on the implementation of HCN-connected systems.Index Terms¿Data parallel algorithm, hypercubes, interconnection networks, loosely-coupled multiprocessors.
On the practical applicability of VC dimension bounds
Authors: Sean B. Holden, Mahesan Niranjan
Venue: Neural Computation (1995)

This article addresses the question of whether some recent Vapnik-Chervonenkis (VC) dimension-based bounds on sample complexity can be regarded as a practical design tool. Specifically, we are interested in bounds on the sample complexity for the problem of training a pattern classifier such that we can expect it to perform valid generalization. Early results using the VC dimension, while being extremely powerful, suffered from the fact that their sample complexity predictions were rather impractical. More recent results have begun to improve the situation by attempting to take specific account of the precise algorithm used to train the classifier. We perform a series of experiments based on a task involving the classification of sets of vowel formant frequencies. The results of these experiments indicate that the more recent theories provide sample complexity predictions that are significantly more applicable in practice than those provided by earlier theories; however, we also find that the recent theories still have significant shortcomings.
Clustering for improved system-level functional partitioning
Authors: Frank Vahid, Daniel D. Gajski
Venue: Proceedings of the 8th international symposium on System synthesis (1995)

Abstract: Partitioning of system functionality for implementation among multiple system components, such as among hardware and software components, is becoming an increasingly important topic. Various heuristics can accomplish such partitioning. We demonstrate that clustering can be used to merge pieces of functionality before applying other heuristics, resulting in reduced runtimes with little or no loss in quality, and often with improvements in quality. In addition, we show that clustering, when used for N-way partitioning, fills the gap between fast heuristics and highly-optimizing heuristics.
Maximizing Robustness in Nonlinear Illposed Inverse Problems
Authors: Kazufumi Ito, Karl Kunisch
Venue: SIAM Journal on Control and Optimization (1995)

A framework for maximizing the robustness of nonlinear illposed inverse problems by choosing appropriate system inputs is presented. This framework is based on maximizing the lowest eigenvalues of the linearized and regularized nonlinear mapping. Stability and sensitivity of the eigenvalues of the linearization are studied. The results are applied to parameter estimation problems for elliptic partial differential equations. Numerical examples illustrating the results are given.
On nominal delay minimization in LUT-based FPGA technology mapping
Authors: Jason Cong, Yuzheng Ding
Venue: Proceedings of the 1995 ACM third international symposium on Field-programmable gate arrays (1995)

We study the nominal delay minimization problem in LUT-based FPGA technology mapping, where interconnect delay is assumed proportional to net fannout size. We prove that the delay-optimal K-LUT mapping problem under the nominal delay model is NP-hard when K&ge;3, and remains NP-hard for duplication-free mapping and tree-based mapping for K&ge;5 (but is polynomial time solvable for K = 2). We also present a simple heuristic to take nominal delay into consideration during LUT mapping for delay minimization.
Designing stimulating programming assignments for an algorithms course: a collection of exercises based on random graphs
Authors: Michael Mitzenmacher
Venue: ACM SIGCSE Bulletin (1996)

The field of random graphs contains many surprising and interesting results. Here we demonstrate how some of these results can be used to develop stimulating, open-ended exercises for courses in algorithms and data structures or graph theory. Specifically, we provide problems for algorithms that compute minimum spanning trees, connected components, maximum flows, and all-pairs shortest paths.
Simulation of communication networks
Authors: Averill M. Law, Michael G. McComas
Venue: Proceedings of the 27th conference on Winter simulation (1995)

This paper discusses how simulation is used to design and analyze communications networks. Topics discussed include: network issues addressed by simulation, simulation software for network modeling, techniques for building valid and credible models, and statistical considerations. A comprehensive example is also given.
Object orientation in multidatabase systems
Authors: Evaggelia Pitoura, Omran Bukhres, Ahmed Elmagarmid
Venue: ACM Computing Surveys (CSUR) (1995)

A multidatabase system (MDBS) is a confederation of preexisting distributed, heterogeneous, and autonomous database systems. There has been a recent proliferation of research suggesting the application of object-oriented techniques to facilitate the complex task of designing and implementing MDBSs. Although this approach seems promising, the lack of a general framework impedes any further development. The goal of this paper is to provide a concrete analysis and categorization of the various ways in which object orientation has affected the task of designing and implementing MDBSs.We identify three dimensions in which the object-oriented paradigm has influenced this task: the general system architecture, the schema architecture, and the heterogeneous transaction management. Then we provide a classification and a comprehensive analysis of the issues related to each of the above dimensions. To demonstrate the applicability of this analysis, we conclude with a comparative review of existing multidatabase systems.
ALGORITHM 643: FEXACT: a FORTRAN subroutine for Fisher's exact test on unordered r&times;c contingency tables
Authors: Cyrus R. Mehta, Nitin R. Patel
Venue: ACM Transactions on Mathematical Software (TOMS) (1986)

The computer code for Mehta and Patel's (1983) network algorithm for Fisher's exact test on unordered r&times;c contingency tables is provided. The code is written in double precision FORTRAN 77. This code provides the fastest currently available method for executing Fisher's exact test, and is shown to be orders of magnitude superior to any other available algorithm. Many important details of data structures and implementation that have contributed crucially to the success of the network algorithm are recorded here.
Designing Efficient Parallel Algorithms on CRAP
Authors: Tzong-Wann Kao, Shi-Jinn Horng, Yue-Li Wang, Horng-Ren Tsai
Venue: IEEE Transactions on Parallel and Distributed Systems (1995)

A cross-bridge reconfigurable array of processors is a parallel processing system which has the ability to change dynamically the supported interconnection scheme during the execution of an algorithm. Based on this architecture, several $O(1)$ time basic operations such as the transpose, the untranspose, the shift, the unshift and the prefix sum of a binary sequence are first proposed. Then, these basic operations can be used to find the $k$th smallest element of $N$$m$ bits unsigned integers in $O(m)$ time using $N$ processors and to sort $N$ data items in $O(1)$ time using $O(N^{{5}\over{3}})$ processors instead of using $O(N^2)$ processors as those proposed by other researchers [2], [4], [8], [12], [17], respectively.Index Terms¿Prefix sum, selection, sort, parallel algorithms, cross-bridge, reconfigurable bus, reconfigurable array of processors.
Matrix Pairs in Two-Dimensional Systems: An Approach Based on Trace Series and Hankel Matrices
Authors: Ettore Fornasini, Maria Elena Valcher
Venue: SIAM Journal on Control and Optimization (1995)

Two-dimensional system dynamics depends on matrix pairs that represent the shift operators along coordinate axes. The structure of a matrix pair is analysed according to its characteristic polynomial and to the traces of suitable matrices in the algebra generated by the elements of the pair. Necessary and sufficient conditions for properties L and P are provided by resorting to Hankel matrix theory. Finite memory and separable systems, as well as two-dimensional systems whose characteristic polynomials exhibit one-dimensional structures, are finally characterized in terms of spectral properties and traces.
A discipline for constructing multiphase communication protocols
Authors: Ching-Hua Chow, Mohamed G. Gouda, Simon S. Lam
Venue: ACM Transactions on Computer Systems (TOCS) (1985)

Many communication protocols can be observed to go through different phases performing a distinct function in each phase. A multiphase model for such protocols is presented. A phase is formally defined to be a network of communicating finite-state machines with certain desirable correctness properties; these include proper termination and freedom from deadlocks and unspecified receptions. A multifunction protocol is constructed by first constructing separate phases to perform its different functions. It is shown how to connect these phases together to realize the multifunction protocol so that the resulting network of communicating finite state machines is also a phase (i.e., it possesses the desirable properties defined for phases). The modularity inherent in multiphase protocols facilitates not only their construction but also their understanding and modification. An abundance of protocols have been found in the literature that can be constructed as multiphase protocols. Three examples are presented here: two versions of IBM's BSC protocol for data link control and a token ring network protocol.
Training with noise is equivalent to Tikhonov regularization
Authors: Chris M. Bishop
Venue: Neural Computation (1995)

It is well known that the addition of noise to the input data of a neural network during training can, in some circumstances, lead to significant improvements in generalization performance. Previous work has shown that such training with noise is equivalent to a form of regularization in which an extra term is added to the error function. However, the regularization term, which involves second derivatives of the error function, is not bounded below, and so can lead to difficulties if used directly in a learning algorithm based on error minimization. In this paper we show that for the purposes of network training, the regularization term can be reduced to a positive semi-definite form that involves only first derivatives of the network mapping. For a sum-of-squares error function, the regularization term belongs to the class of generalized Tikhonov regularizers. Direct minimization of the regularized error function provides a practical alternative to training with noise.
Smarter recompilation
Authors: Robert W. Schwanke, Gail E. Kaiser
Venue: ACM Transactions on Programming Languages and Systems (TOPLAS) (1988)

Tichy's Smart Recompilation method can be made smarter by permitting benign type inconsistencies between separately compiled modules. This enhanced method helps the programmer to make far-reaching changes in small, manageable steps.