ppxscal/embedding_network huggingface dataset:
Variational approach to the sixth-order boundary value problems
Authors: Ji-Huan He
Venue: Applied Mathematics and Computation (2003)

Recently, Wazwaz [Appl. Math. Comput. 118 (2001) 311-325] applied the Adomian's decomposition method to solve analytically the solution of sixth-order boundary value problems. The same problem is discussed via the variational principle, which reveals to be much more simpler and much more efficient.
Formulation of the Audze--Eglais uniform Latin hypercube design of experiments
Authors: S. J. Bates, J. Sienz, D. S. Langley
Venue: Advances in Engineering Software (2003)

This paper describes a method for formulating the Audze-Eglais Uniform Latin Hypercube design of experiments (DoE). The formulation of the Audze-Eglais DoE has not been reported in any previous research.The principle of the Audze-Eglals DoE is to distribute experiment points as uniformly as possible within the design variable domain. This is achieved by minimizing the potential energy of the points of a DoE. The DoE for N variables and P experiments is independent of the application under consideration, so once the design is formulated for P points and N design variables, it is stored in a matrix and need not be formulated again.The generation of the Audze-Eglais DoE is time consuming and requires optimization to solve the minimization problem. Therefore, the major aim of the paper is to identify a design variable encoding method for use in optimization. The two methods for encoding the DoE for use in the optimizer are presented. The method adopted in this study uses the co-ordinates of the plan points as design variables. The results for the potential energy are compared to published Audze-Eglais Uniform Latin Hypercube DoE and to random sampling Latin Hypercube DoE. The results indicate that the method works well and improvement over previous results has been achieved.
A Geometric Theory for Preconditioned Inverse Iteration. III:A Short and Sharp Convergence Estimate for Generalized EigenvalueProblems.
Authors: Andrew Knyazev, Klaus Neymeyr
Venue:  (2001)

In two previous papers by Neymeyr: A geometric theory for preconditioned inverse iteration I: Extrema of the Rayleigh quotient, LAA 322: (1-3), 61-85, 2001, and A geometric theory for preconditioned inverse iteration II: Convergence estimates, LAA 322: (1-3), 87-104, 2001, a sharp, but cumbersome, convergence rate estimate was proved for a simple preconditioned eigensolver, which computes the smallest eigenvalue together with the corresponding eigenvector of a symmetric positive definite matrix, using a preconditioned gradient minimization of the Rayleigh quotient. In the present paper, we discover and prove a much shorter and more elegant, but still sharp in decisive quantities, convergence rate estimate of the same method that also holds for a generalized symmetric definite eigenvalue problem. The new estimate is simple enough to stimulate a search for a more straightforward proof technique that could be helpful to investigate such practically important method as the locally optimal block preconditioned conjugate gradient eigensolver. We demonstrate practical effectiveness of the latter for a model problem, where it compares favorably with two well-known Jacobi-Davidson type methods, JDQR and JDCG.
Searching social networks
Authors: Bin Yu, Munindar P. Singh
Venue: Proceedings of the second international joint conference on Autonomous agents and multiagent systems (2003)

A referral system is a multiagent system whose member agents are capable of giving and following referrals. The specific cases of interest arise where each agent has a user. The agents cooperate by giving and taking referrals so each can better help its user locate relevant information. This use of referrals mimics human interactions and can potentially lead to greater effectiveness and efficiency than in single-agent systems.Existing approaches consider what referrals may be given and treat the referring process simply as path search in a static graph. By contrast, the present approach understands referrals as arising in and influencing dynamic social networks, where the agents act autonomously based on local knowledge. This paper studies strategies using which agents may search dynamic social networks. It evaluates the proposed approach empirically for a community of AI scientists (partially derived from bibliographic data). Further, it presents a prototype system that assists users in finding other users in practical social networks.
B-Course: A Web Service for Bayesian Data Analysis
Authors: Petri Myllymaki, Tomi Silander, Henry Tirri, Pekka Uronen
Venue: Proceedings of the 13th IEEE International Conference on Tools with Artificial Intelligence (2001)

B-Course (http://b-course.cs.helsinki.fi) is a free web-based online data analysis tool, which allows the users to analyze their data for multivariate probabilistic dependencies. These dependencies are represented as Bayesian network models. In addition to this, B-Course also offers facilities for inferring certain type of causal dependencies from the data. The software uses a novel "tutorial style" user-friendly interface which intertwines the steps in the data analysis with support material that gives an informal introduction to the Bayesian approach adopted. Although the analysis methods, modeling assumptions and restrictions are totally transparent to the user, this transparency is not achieved at the expense of analysis power: with the restrictions stated in the support material, B-Course is a powerful analysis tool exploiting several theoretically elaborate results developed recently in the fields of Bayesian and causal modeling. B-Course can be used with most web-browsers (even Lynx), and the facilities include features such as automatic missing data handling and discretization, a flexible graphical interface for probabilistic inference on the constructed Bayesian network models (for Java enabled browsers), automatic pretty-printed layout for the networks, exportation of the models, and analysis of the importance of the derived dependencies. In this paper we discuss both the theoretical design principles underlying the B-Course tool, and the pragmatic methods adopted in the implementation of the software.
Finite transition matrices for permutations avoiding pairs of length four patterns
Authors: Darla Kremer, Wai Chee Shiu
Venue: Discrete Mathematics (2003)

We show that the four classes of pattern avoiding permutations, Sn(1234, 3214), Sn(4123, 3214), Sn(2341, 2143) and Sn(1234, 2143) are enumerated by the formula (4n-1 + 2)/3. In an electronic appendix we provide finite transition matrices for the number |Sn(u, v)| of permutations avoiding pairs (u, v) of length four patterns where u contains the subsequence 123 and v contains the subsequence 321 as well as a transition matrix for |Sn(1234, 43215)|.
Case study: fishing for information on the Internet
Authors: R. Mitchell, D. Day, L. Hirschman
Venue: Proceedings of the 1995 IEEE Symposium on Information Visualization (1995)

As the Internet continues to grow, the amount of accessible information becomes increasingly vast. Search tools exist that allow users to find relevant information. However, a search can often produce such a large amount of data that it becomes hard to ferret out the most appropriate and highest quality information. In addition, some search tools lose valuable information when displaying the results to the user. The paper describes a search visualization tool, called FISH, for viewing hierarchically structured information and managing information overload. FISH (Forager for the Information Super Highway) allows users to visualize the results of search requests across large document spaces in a way that preserves the structure of the information space. FISH displays the returned documents as rectangles, using a combination of order, indentation, size, and color to denote document hierarchy, the score of the documents with respect to the search, and other data attributes. In addition, the user can navigate through the document space for in-depth probing and refinement.
The creation of novelty in artificial chemistries
Authors: Dominique Groß, Barry McMullin
Venue: Proceedings of the eighth international conference on Artificial life (2002)

We observe that the world surrounding us perpetually creates novelty. The question we examine in this article is whether it is possible to build computer models that are similarly creative. The discussion focuses specifically on artificial chemistries.
IRIDIUM: a program to model reaction of silicate liquid infiltrating a porous solid assemblage
Authors: Alan E. Boudreau
Venue: Computers Geosciences (2003)

The migration of silicate liquid through porous rock can give rise to compositional changes in both the liquid and the host solid assemblage that are important in a number of fields of igneous petrology. Ongoing studies in numerical models of crystallization and compaction behavior in layered intrusions by our group have lead to a need to incorporate more realistic silicate crystallization behavior. The computer program IRIDIUM incorporates liquid-mineral equilibria with one-dimensional transport equations for modeling magmatic infiltration-reaction (IR) phenomenon. The program allows calculation of mineral precipitation/dissolution and chromatographic fronts as silicate liquid percolates through a porous solid matrix. The liquid-mineral equilibria part of the IRIDIUM program is based on the free energy minimization algorithm used in the MELTS software algorithm of Ghiorso and coworkers and includes trace element modeling. The IRIDIUM program incorporates both general and compaction-driven thermal and mass transport equations. A simple example involving infiltration metasomatism in olivine cumulates in the Muskox intrusion shows some of the capabilities of the program.
Accurate Discretization for Singular Perturbations: The One-Dimensional Case
Authors: X. C. Hu, T. A. Manteuffel, S. McCormick, Thomas F. Russell
Venue:  (1994)

This paper develops a discretization method for one-dimensional singular perturbation problems based on a Petrov-Galerkin finite element, or an equivalent finite volume, scheme. The method is unique in that: its discretization error has a bound that is second order in the mesh size and uniform in the perturbation parameter; it satisfies a local discrete conservation law; and it exhibits a discrete maximum principle. Numerical results are included for comparison with the theory.
Quality-driven software architecture composition
Authors: Hans de Bruin, Hans van Vliet
Venue: Journal of Systems and Software (2003)

This paper discusses an approach for the top-down composition of software architectures. First, an architecture is derived that addresses functional requirements only. This architecture contains a number of variability points which are next filled in to address quality concerns. The quality requirements and associated architectural solution fragments are captured in a so-called feature-solution (FS) graph. The solution fragments captured in this graph are used to iteratively compose an architecture driven by quality requirements. Our versatile composition technique allows for pre- and post-refinements, refinements that involve multiple variability points, and functionality extensions. In addition, the usage of the FS-graph supports aspect-oriented programming at the architecture level.
Analysis and Design of Virtual Reality Applications in the WEB: A Case of Study
Authors: A de Abreu
Venue: Proceedings of the 1999 International Conference on Information Visualisation (1999)

The new coming era of the WEB represents a challenge in the development analysis of software systems, incorporating new technologies to access and present information, that combines 3D images, sounds, video, and text, in a way that the user gets involved in the interaction with it. This is known as non-inmersive Virtual Reality. Reusing software to solve such problems is then necessary. On the other hand, there are no other known specific methods or/and techniques for the development of applications on the WEB. In this article, we present an analysis and design of a WEB application,. a Virtual Reality Architecture Editor (EVA)[1], using the OOSE method for defining the system architecture, where the reused and developed parts are showed, along with their communication relationships. The ACM Portal is published by the Association for Computing Machinery. Copyright © 2010 ACM, Inc. Terms of Usage Privacy Policy Code of Ethics Contact Us Useful downloads: Adobe Acrobat QuickTime Windows Media Player Real Player
Fast Algorithms for $N$-body Simulation
Authors: Sridhar Sundaram
Venue:  (1993)

Many physical models require the simulation of a large number ($N$) of particles interacting through pair-wise inverse square law forces. $N$-body simulations are employed in fluid-dynamics, biochemistry, astrophysics, electrodynamics and molecular dynamics. The computational problem is intrinsically hard and these simulations are time-intensive. Existing algorithms exploit either the spatial proximity of particles or the temporal proximity of states. In this thesis, we formally combine the two approaches and present an algorithm with sequential time complexity $O(N^{4/3})$ to integrate $N$ uniformly distributed particles in 3D over one crossing time against the $O(N^{8/3})$ complexity of the direct method. Under reasonable assumptions, our algorithm is optimal. The core of the algorithm is the temporal multipole expansion of the field in terms of the space-time coordinates of the field-point. We also present efficient parallel algorithms on the 2D and 3D Mesh and Hypercube which amortize communication costs through temporal multipole expansions. The parallel algorithms offer an order of magnitude improvement over existing algorithms for even $10^{4}$ particles. A sequential implementation of the algorithm for two-dimensional $N$-body systems shows the predicted asymptotic scaling. A parallel version on a 16-processor Intel iPSC/860 machine is also in conformance with theoretical expectations. The ACM Portal is published by the Association for Computing Machinery. Copyright © 2010 ACM, Inc. Terms of Usage Privacy Policy Code of Ethics Contact Us Useful downloads: Adobe Acrobat QuickTime Windows Media Player Real Player
Direct Manipulation of Isosurfaces and Cutting Planes in Virtual Environments
Authors: Tom Meyer, Al Globus
Venue:  (1993)

We present some novel interface techniques for the visualization of scalar field data in virtual reality (VR) environments. In particular, we discuss the direct manipulation of isosurfaces and cutting planes and give general guidelines for design of user interfaces and algorithms for scientific visualization in virtual environments. This work was motivated by the need to visualize scalar field data from computational fluid dynamics (CFD) calculations interactively in the Virtual Wind Tunnel at NASA Ames, but the techniques are applicable to other problem areas, including medical imaging and geological and mathematical visualization.
"Where Are You Pointing At?" A Study of Remote Collaboration in a Wearable Videoconference System
Authors: Martin Bauer, Gerd Kortuem, Zary Segall
Venue: Proceedings of the 3rd IEEE International Symposium on Wearable Computers (1999)

This paper reports on an empirical study aimed at evaluating the utility of a reality-augmenting telepointer in a wearable videoconference system. Results show that using this telepointer a remote expert can effectively guide and direct a field worker's manual activities. By analyzing verbal communication behavior and pointing gestures, we were able to determine that experts overwhelmingly preferred pointing for guiding workers through physical tasks.
On Petrov-Galerkin Formulations for the Linear Hyperbolic Equation
Authors: L. P. Franca, A. Russo
Venue:  (1998)

We consider conforming Petrov-Galerkin formulations for the advective and advective-diffusive equations. For the linear hyperbolic equation, the continuous formulation is set up using different spaces and the discretization follows with different ``bubble'''' enrichments for the test and trial spaces. Boundary conditions for residual-free bubbles are modified to accommodate with the first order equation case and regular bubbles are used to enrich the other space. Using piecewise linears with these enrichments, the final formulations are shown to be equivalent to the SUPG method, provided the data is assumed to be piecewise constant. Generalization to include diffusion is also presented.
A note on maximal partial spreads with deficiency q + 1, q even
Authors: Dieter Jungnickel, Leo Storme
Venue: Journal of Combinatorial Theory Series A (2003)

We settle an open case for the spectrum of sizes of maximal partial spreads in PG(3, q) by constructing an MPS of deficiency q + 1 for all even q ≥ 8.
Literacy in the Information Age: Inquiries Into Meaning Making With New Technologies
Authors: Bertram C. Bruce
Venue:  (2003)

:Educators today want to go beyond how-to manuals and publications that merely celebrate the many exciting new technologies as they appear in schools. Students are immersed in an evolving world of new technology development in which they are not passive recipients of these technologies but active interpreters of them. How do you help learners interpret these technologies as we all become immersed in the new information age?Editor Bertram C. Bruce provides this collection of 32 Technology Departments from the Journal of Adolescent & Adult Literacy covering the 1998 to 2002 volume years, which examines critical aspects of literacy in the new information age and the complex issues surrounding the use of new technologies. The pieces build on specific examples from classrooms, Web use, and other experiences with new digital information and communication environments.Bruce has grouped the chapters conceptually rather than chronologically into the following six sections: Historical Perspective, New Media Practices, Personal Meanings, Ethical and Policy Issues, Learning Opportunities, and Community. The book also addresses issues such as credibility, access, and privacy, and most centrally an understanding of what new media mean for teaching, learning, and literacy development.Educators feel the challenge of preparing students to live productively within this emerging world and deciding what learning experiences can best prepare students for becoming literate in today's world. This collection will provide the tools for you and your students to explore the way new literacies are evolving as they become ever more central in your lives.
A Selection Technique for Replicated Multicast Video Servers
Authors: Akihito Hiromori, Hirozumi Yamaguchi, Keiichi Yasumoto, Teruo Higashino, Kenichi Taniguchi
Venue: Proceedings of the 2002 International Conference on Parallel Processing (2002)

In this paper, we propose a selection technique for replicated multicast video servers. We assume that each replicated video server transmits the same video source as different quality levels' multicast streams. Using an IGMP facility like mtrace, each receiver monitors packet count information of those streams on routers and periodically selects the one which is expected to provide low loss rate and to be suitable for the current available bandwidth of receivers. Moreover, collection of packet count information is done in a scalable and efficient manner by sharing the collected information across receivers. Our experimental results using the networksimulator have shown that our method could achieve much higher quality satisfaction of receivers, under the reasonable amount of tracing traffic.
Performance of the ISIS Distributed Computing Toolkit
Authors: Kenneth P. Birman, Timothy Clark
Venue:  (1994)

The ISIS Toolkit is a programming environment for building process-group structured distributed software. The system is widely used in settings requiring high reliability, strong distributed consistency guarantees, and highspeed communication. In this paper, we describe experimental studies of ISIS performance. Our work explores the impact of hardware support for multicast performance, with a focus on flow control mechanisms. The use of hardware multicast in ISIS has not been discussed elsewhere. One conclusion of the paper is that although ISIS performance is limited primarily by flow control considerations, this type of hardware support can lead to significant performance improvements for certain communication patterns. A second conclusion was that the ISIS flow-control problem is surprisingly difficult. More work in this area, and on the underlying operating system communications layer (UDP), could have significant impact on the system. Keywords and phrases: Distributed computing, performance, process groups, atomic broadcast, causal and total message ordering, cbcast, abcast, multiple process groups, hardware multicast, IP multicast, virtual synchrony, faulttolerance.
On Properties of Random Reductions
Authors: Pankaj Rohatgi
Venue:  (1993)

Randomness is widely accepted as a powerful computational resource because the most elegant and efficient solutions to several computational problems are randomized. A recurrent theme in the theory of randomized computation is the notion of a random reduction. Random reductions are similar to many-one ($\leq^{P}_{m}$) reductions except for the fact that they are carried out by probablistic transducers which may make errors with small probability. Such reductions are used explicitly in many basic results in complexity theory and implicitly in several randomized algorithms. This thesis investigates the properties of random reductions as a tool towards understanding the power and limitations of randomness. We first prove some startling results which indicate that random reductions can be quite successful in reducing harder problems to simpler ones. We then propose the thesis that in many situations there is a sharp {\em probability threshold} which governs just how successful random reductions can be in this regard. As evidence, we prove that for several complexity classes ${\cal C}$, under standard assumptions, there exist corresponding {\em probability thresholds\/} ${\cal C}_T$, such that random reductions with success probability below ${\cal C}_T$ can reduce the hardest languages in ${\cal C}$ to simpler ones but reductions with success probability above ${\cal C}_T$ cannot do so. Based on these thresholds, we then propose a meaningful definition of completeness under random reductions which resolves several anomalies caused by the traditional definitions which did not place much emphasis on the success probability. The results described above depend on standard but unproven complexity-theoretic assumptions. In order to show that such behavior is inherent to random reductions and not an artifact introduced by these assumptions, we also prove that it is present in very high complexity classes {\em without any assumptions}. In this thesis we also examine other basic aspects of random reducibility. We prove several {\em absolute} separation results between the notions of completeness under various polynomial-time random reductions with different success probabilities and between various random reductions and deterministic polynomial-time reductions. In addition, we also prove new results on the consequences of having random reductions from NP-complete sets to sparse sets.