ppxscal/embedding_network huggingface dataset:
Numerical Solution of the Three-Dimensional Ginzburg--Landau Models Using Artificial Boundary
Authors: Qiang Du, Xiaonan Wu
Venue: SIAM Journal on Numerical Analysis (1999)

For three-dimensional simulations of the vortex phenomena in superconductors based on the Ginzburg--Landau (GL) theory, the physical variables must be solved in the whole space in general. Exact boundary conditions on an artificial boundary are discussed to reformulate the problem in a finite domain. Approximations of these boundary conditions with high accuracy are given, and their convergence properties are examined. Error estimates are derived for the finite element approximations with the approximate boundary conditions.
A new method for similarity indexing of market basket data
Authors: Charu C. Aggarwal, Joel L. Wolf, Philip S. Yu
Venue: Proceedings of the 1999 ACM SIGMOD international conference on Management of data (1999)

In recent years, many data mining methods have been proposed for finding useful and structured information from market basket data. The association rule model was recently proposed in order to discover useful patterns and dependencies in such data. This paper discusses a method for indexing market basket data efficiently for similarity search. The technique is likely to be very useful in applications which utilize the similarity in customer buying behavior in order to make peer recommendations. We propose an index called the signature table, which is very flexible in supporting a wide range of similarity functions. The construction of the index structure is independent of the similarity function, which can be specified at query time. The resulting similarity search algorithm shows excellent scalability with increasing memory availability and database size.
Some Design Aspects of a Two-Stage Rail-to-Rail CMOS Op Amp
Authors: Sander L. J. Gierkink, Peter J. Holzmann, Remco J. Wiegerink, Roelof F. Wassenaar
Venue: Analog Integrated Circuits and Signal Processing (1999)

A two-stage low-voltage CMOS op amp with rail-to-rail input and output voltage ranges is presented. The circuit uses complementary differential input pairs to achieve the rail-to-rail common-mode input voltage range. The differential pairs operate in strong inversion, and the constant transconductance is obtained by keeping the sum of the square roots of the tail currents constant. Such an input stage has an offset voltage which depends on the common input voltage level, resulting in a poor common-mode rejection ratio. Therefore, special attention has been given to the reduction of the op amp&rsquo;s systematic offset voltage. Gain-boost amplifiers are connected in a special way to provide not only an increase of the low-frequency open-loop gain, but also to provide a significant reduction of the systematic offset voltage.
On the Topological Derivative in Shape Optimization
Authors: J. Sokolowski, A. Zochowski
Venue: SIAM Journal on Control and Optimization (1999)

In this paper the topological derivative for an arbitrary shape functional is defined. Examples are provided for elliptic equations and the elasticity system in the plane. The topological derivative can be used for solving shape optimization problems in structural mechanics.
Note on a Fourth Order Finite Difference Scheme for the Wave Equation
Authors: Yuehong Qian, Jose Jimenez
Venue: Journal of Scientific Computing (1998)

The linear wave equation is one of the simplest partial differential equations. It has been used as a test equation of hyperbolic systems for different numerical schemes &lsqb;Richtmyer and Morton (1967)&semi; Euvrard (1994)&semi; and Lax (1990&rsqb;. In this short note, a Fourth order finite difference scheme for this equation is proposed and studied. Numerical simulations confirm our theoretical analyses of accuracy and stability condition. It will be interesting to extend the scheme to nonlinear hyperbolic systems.
Computer modelling of fallen snow
Authors: Paul Fearing
Venue: Proceedings of the 27th annual conference on Computer graphics and interactive techniques (2000)

In this paper, we present a new model of snow accumulation and stability for computer graphics. Our contribution is divided into two major components, each essential for modelling the appearance of a thick layer of snowfall on the ground. Our accumulation model determines how much snow a particular surface receives, allowing for such phenomena as flake flutter, flake dusting and wind-blown snow. We compute snow accumulation by shooting particles upwards towards the sky, giving each source surface independent control over its own sampling density, accuracy and computation time. Importance ordering minimises sampling effort while maximising visual information, generating smoothly improving global results that can be interrupted at any point. Once snow lands on the ground, our stability model moves material away from physically unstable areas in a series of small, simultaneous avalanches. We use a simple local stability test that handles very steep surfaces, obstacles, edges, and wind transit. Our stability algorithm also handles other materials, such as flour, sand, and flowing water.
Solution of Parabolic Equations by Backward Euler-Mixed Finite Element Methods on a Dynamically Changing Mesh
Authors: Clint Dawson, Robert Kirby
Venue: SIAM Journal on Numerical Analysis (1999)

We develop and analyze methods based on combining the lowest-order mixed finite element method with backward Euler time discretization for the solution of diffusion problems on dynamically changing meshes. The methods developed are shown to preserve the optimal rate error estimates that are well known for static meshes. The novel aspect of the scheme is the construction of a linear approximation to the solution, which is used in projecting the solution from one mesh to another. Extensions to advection-diffusion equations are discussed, where the advection is handled by upwinding. Numerical results validating the theory are also presented.
Server selection on the World Wide Web
Authors: Nick Craswell, Peter Bailey, David Hawking
Venue: Proceedings of the fifth ACM conference on Digital libraries (2000)

Significant efforts are being made to digitize rare and valuable library materials, with the goal of providing patrons and historians digital facsimiles that capture the "look and feel" of the original materials. This is often done by digitally photographing the materials and making high resolution 2D images available. The underlying assumption is that the objects are flat. However, older materials may not be flat in practice, being warped and crinkled due to decay, neglect, accident and the passing of time. In such cases, 2D imaging is insufficient to capture the "look and feel" of the original. For these materials, 3D acquisition is necessary to create a realistic facsimile. This paper outlines a technique for capturing an accurate 3D representation of library materials which can be integrated directly into current digitization setups. This will allow digitization efforts to provide patrons with more realistic digital facsimile of library materials.
Discretization on Unstructured Grids for Inhomogeneous, Anisotropic Media. Part I: Derivation of the Methods
Authors: I. Aavatsmark, T. Barkve, O. Bøe
Venue: SIAM Journal on Scientific Computing (1998)

Discretization methods are proposed for control-volume formulations on polygonal and triangular grid cells in two space dimensions. The methods are applicable for any system of conservation laws where the flow density is defined by a gradient law, like Darcy's law for porous-media flow. A strong feature of the methods is the ability to handle media inhomogeneities in combination with full-tensor anisotropy. This paper gives a derivation of the methods, and the relation to previously published methods is also discussed. A further discussion of the methods, including numerical examples, is given in the companion paper, Part II [SIAM J. Sci. Comput., pp. 1717--1736].
A Wavelet-Optimized, Very High Order Adaptive Grid and Order Numerical Method
Authors: Leland Jameson
Venue: SIAM Journal on Scientific Computing (1998)

Wavelets detect information at different scales and at different locations throughout a computational domain. Furthermore, wavelets can detect the local polynomial content of computational data. Numerical methods are most efficient when the basis functions of the method are similar to the data present. By designing a numerical scheme in a completely adaptive manner around the data present in a computational domain, one can obtain optimal computational efficiency. This paper extends the numerical wavelet-optimized finite difference (WOFD) method to arbitrarily high order, so that one obtains, in effect, an adaptive grid and adaptive order numerical method which can achieve errors equivalent to errors obtained with a "spectrally accurate" numerical method.
Scheduling critical channels in conservative parallel discrete event simulation
Authors: Z. Xiao, B. Unger, R. Simmonds, J. Cleary
Venue: Proceedings of the thirteenth workshop on Parallel and distributed simulation (1999)

This paper introduces the Critical Channel Traversing (CCT) algorithm, a new scheduling algorithm for both sequential and parallel discrete event simulation. CCT is a general conservative algorithm that is aimed at the simulation of low-granularity network models on shared-memory multi-processor computers.An implementation of the CCT algorithm within a kernel called TasKit has demonstrated excellent performance for large ATM network simulations when compared to previous sequential, optimistic and conservative kernels. TasKit has achieved two to three times speedup on a single processor with respect to a splay tree central-event-list based sequential kernel. On a 16 processor (R8000) Silicon Graphics PowerChallenge, TasKit has achieved an event-rate of 1.2 million events per second and a speedup of 26 relative to the sequential kernel for a large ATM network model.Performance is achieved through a multi-level scheduling scheme that supports the scheduling of large grains of computation even with low-granularity events. Performance is also enhanced by supporting good cache behavior and automatic load balancing.The paper describes the algorithm and its motivation, proves its correctness and briefly presents performance results for TasKit.
The friendly intelligent tutoring environment
Authors: Ljubomir Jerinic, Vladan Devedzic
Venue: ACM SIGCHI Bulletin (2000)

The advancement of using the Artificial Intelligence (AI) methods and techniques in design Intelligent Tutoring Systems (ITSs) makes understanding them more difficult, so that teachers are less and less prepared to accept these systems. As a result, the gap between researchers in the field of ITSs and the educational community is constantly widening. While ITSs are becoming more common and proving to be increasingly effective, each one must still be built from scratch at a significant cost. Also present ITSs need quite big development environments, huge computing resources and, in consequence, are expensive and hardly portable to personal computers. This paper describes our efforts toward developing uniform data, explanation and control structures that can be used by a wide circle of authors who are involved in building ITSs (e.g., domain experts, teachers, curriculum developers, etc.) that is, the model of the ITSs framework, the GET-BITS model.
Component-based e-commerce: assessment of current practices and future directions
Authors: Martin Bichler, Arie Segev, J. Leon Zhao
Venue: ACM SIGMOD Record (1998)

Component-based e-commerce technology is a recent trend towards resolving the e-commerce challenge at both system and application levels. Instead of delivering a system as a prepacked monolith system containing any conceivable feature, component-based systems consist of a lightweight kernel to which new features can be added in the form of components. In order to identify the central problems in component-based e-commerce and ways to deal with them, we investigate prototypes, technologies, and frameworks that will transcend the current state of the practice in Internet commerce. In this paper, we first discuss the current practices and trends in component-based electronic commerce based on the International Workshop on Component-based Electronic Commerce. Then, we investigate a number of research issues and future directions in component-based development for electronic commerce.
A Root System Criterion for Fully Commutative and Short Braid-Avoiding Elements in Affine Weyl Groups
Authors: Paola Cellini, Paolo Papi
Venue: Journal of Algebraic Combinatorics: An International Journal (2000)

We provide simple characterizations of short-braid avoiding and fully commutative elements in an affine Weyl group W, generalizing results of Fan and Stembridge for finite Weyl groups. Our results rely on the combinatorics of the compatible subsets of the root system of W.
Cognitive modeling demonstrates how people use anticipated location knowledge of menu items
Authors: Anthony J. Hornof, David E. Kieras
Venue: Proceedings of the SIGCHI conference on Human factors in computing systems: the CHI is the limit (1999)

This research presents cognitive models of a person selecting an item from a familiar, ordered, pull-down menu. Two different models provide a good fit with human data and thus two different possible explanations for the low- level cognitive processes involved in the task. Both models assert that people make an initial eye and hand movement to an anticipated target location without waiting for the menu to appear. The first model asserts that a person knows the exact location of the target item before the menu appears, but the model uses nonstandard Fitts law coefficients to predict mouse pointing time. The second model asserts that a person would only know the approximate location of the target item, and the model uses Fitts law coefficients better supported by the literature. This research demonstrates that people can develop considerable knowledge of locations in a visual task environment, and that more work regarding Fitts law is needed.
On Updating Problems in Latent Semantic Indexing
Authors: Hongyuan Zha, Horst D. Simon
Venue: SIAM Journal on Scientific Computing (1999)

We develop new SVD-updating algorithms for three types of updating problems arising from latent semantic indexing (LSI) for information retrieval to deal with rapidly changing text document collections. We also provide theoretical justification for using a reduced-dimension representation of the original document collection in the updating process. Numerical experiments using several standard text document collections show that the new algorithms give higher (interpolated) average precisions than the existing algorithms, and the retrieval accuracy is comparable to that obtained using the complete document collection.
Grammatical Inference using an Adaptive Recurrent Neural Network
Authors: Li-Hui Chen, Hock-Chuan Chua, Poy-Boon Tan
Venue: Neural Processing Letters (1998)

In this study, we proposed an adaptive recurrent neural network that is capable of inferring a regular grammar, and at the same time of extracting the underlying grammatical rules emulated by a finite-state automata. Our proposed network adapts from an initial analog phase, which has good training behavior, to a discrete phase for automatic rule extraction. A modified objective function is proposed to accomplish the discretisation process as well as logic learning. Comparison on learning Tomita grammars shows that our network has a significant advantage over other approaches.
Analysis of Iterative Line Spline Collocation Methods for Elliptic Partial Differential Equations
Authors: A. Hadjidimos, E. N. Houstis, J. R. Rice, E. Vavalis
Venue: SIAM Journal on Matrix Analysis and Applications (1999)

In this paper we present the convergence analysis of iterative schemes for solving linear systems resulting from discretizing multidimensional linear second-order elliptic partial differential equations (PDEs) defined in a hyperparallelepiped $\Omega$ and subject to Dirichlet boundary conditions on some faces of $\Omega$ and Neumann on the others, using line cubic spline collocation (LCSC) methods. Specifically, we derive analytic expressions or obtain sharp bounds for the spectral radius of the corresponding Jacobi iteration matrix and from this we determine the convergence ranges and compute the optimal parameters for the extrapolated Jacobi and successive overrelaxation (SOR) methods. Experimental results are also presented.
Intelligent Analysis and Off-Line Debugging of VLSI Device Test Programs
Authors: Yuhai Ma, Wanchun Shi
Venue: Journal of Electronic Testing: Theory and Applications (1999)

Today&lsquo;s microelectronics researchers design VLSI devices to achieve highly differentiated devices, both in performance and functionality. As VLSI devices become more complex, VLSI device testing becomes more costly and time consuming. The increasing test complexity leads to longer device test programs development time as well as more expensive test systems, and debugging test programs is a great burden to the test programs development. On the other hand, there is little formal theory of debugging, and attempts to develop a methodology of debugging are rare. The aim of the investigation in this paper is to create a theory to support analysis and debugging of VLSI device test programs, and then, on the basis of this theory, design and develop an off-line debugging environment, OLDEVDTP, for the creation, analysis, checking, identifying, error location, and correction of the device test programs off-line from the target VLSI test system, to achieve a dramatic cost and time reduction. In the paper, fuzzy comprehensive evaluation techniques are applied to the program analysis and debugging process to reduce restrictions caused by computational complexity. Analysis, design, and implementation of OLDEVDTP are also addressed in the paper.
Efficient model reduction of interconnect via approximate system gramians
Authors: Jing-Rebecca Li, Jacob White
Venue: Proceedings of the 1999 IEEE/ACM international conference on Computer-aided design (1999)

Krylov-subspace based methods for generating low-order models of complicated interconnect are extremely effective, but there is no optimality theory for the resulting models. Alternatively, methods based on truncating a balanced realization (TBR), in which the observability and controllability gramians have been diagonalized, do have an optimality property but are too computationally expensive to use on complicated problems. In this paper we present a method for computing reduced-order models of interconnect by projection via the orthogonalized union of the approximate dominant eigenspaces of the system's controllability and observability gramians. The approximate dominant eigenspaces are obtained efficiently using an iterative Lyapunov equation solver, Vector ADI, which requires only linear matrix-vector solves. A spiral inductor and a transmission line example are used to demonstrate that the new method accurately approximates the TBR results and gives much more accurate wideband models than Krylov subspace-based moment matching methods.
The Damocles Sword of Academic Publishing: sharper students or duller sword in the MIS field?
Authors: Kai Larsen
Venue: Crossroads (1998)

Doctoral students often find it hard to understand at what level of productivity they should be. Through an analysis of resums of doctoral students in the Management Information Systems (MIS) field, a better understanding of what is expected of current students as compared to former students is achieved. Both conference presentations and publications in journals are examined. Finally, there is an examination of whether the quantity of publications can be related to the ranking of the school that a student attends.
A workflow-based electronic marketplace on the Web
Authors: Asuman Dogac, Ilker Durusoy, Sena Arpinar, Nesime Tatbul, Pinar Koksal, Ibrahim Cingil, Nazife Dimililer
Venue: ACM SIGMOD Record (1998)

In this paper, we describe an architecture for an open marketplace exploiting the workflow technology and the currently emerging data exchange and metadata representation standards on the Web. In this market architecture electronic commerce is realized through the adaptable workflow templates provided by the marketplace to its users. Having workflow templates for electronic commerce processes results in a component-based architecture where components can be agents (both buying and selling) as well as existing applications invoked by the workflows. Other advantages provided by the workflow technology are forward recovery, detailed logging of the processes through workflow history manager and being able to specify data and control flow among the workflow components. In the architecture proposed, the resources expose their metadata using Resource Description Framework (RDF) to be accessed by the resource discovery agents and their content through Extensible Markup Language (XML) to be accessed by the selling agents by using Document Object Model (DOM). The common set of Document Type Definitions (DTDs) are used to eliminate the need for an ontology. The marketplace contains an Intelligent Directory Service (IDS) which makes it possible for agents to find out about each other through a match making mechanism. References to the related Document Type Definitions (DTDs) are stored in IDS. The IDS also contains the template workflows for buying and selling processes.
An Overview of Public, Research and Private Data Networks
Authors: Hamad Al-Sulaiym, Abdulaziz Al-Muammar, Saad Haj Bakry
Venue: International Journal of Network Management (1997)

This article is an overview of 137 data networks available in different parts of the world including 66 public networks, 41 research networks, and 30 special or private networks. The overview emphasizes the importance of data networks for different applications, and illustrates their worldwide integration through the Internet. &copy; 1997 John Wiley Sons, Ltd.
The 3L Algorithm for Fitting Implicit Polynomial Curves and Surfaces to Data
Authors: Michael M. Blane, Zhibi Lei, Hakan Çivi, David B. Cooper
Venue: IEEE Transactions on Pattern Analysis and Machine Intelligence (2000)

In this paper, we introduce a completely new approach to fitting implicit polynomial geometric shape models to data and to studying these polynomials. The power of these models is in their ability to represent nonstar complex shapes in two- (2D) and three-dimensional (3D) data to permit fast, repeatable fitting to unorganized data which may not be uniformly sampled and which may contain gaps, to permit position-invariant shape recognition based on new complete sets of Euclidean and affine invariants and to permit fast, stable single-computation pose estimation. The algorithm represents a significant advancement of implicit polynomial technology for four important reasons. First, it is orders of magnitude faster than existing fitting methods for implicit polynomial 2D curves and 3D surfaces, and the algorithms for 2D and 3D are essentially the same. Second, it has significantly better repeatability, numerical stability, and robustness than current methods in dealing with noisy, deformed, or missing data. Third, it can easily fit polynomials of high, such as 14th or 16th, degree. Fourth, additional linear constraints can be easily incorporated into the fitting process, and general linear vector space concepts apply.