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Model of visual contrast gain control and pattern masking
 Journal of the Optical Society of America A
, 1997
"... We have implemented a model of contrast gain control in human vision which incorporates a number of key features, including a contrast sensitivity function, multiple oriented bandpass channels, accelerating nonlinearities, and a divisive inhibitory gaincontrol pool. The parameters of this model ha ..."
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Cited by 139 (4 self)
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We have implemented a model of contrast gain control in human vision which incorporates a number of key features, including a contrast sensitivity function, multiple oriented bandpass channels, accelerating nonlinearities, and a divisive inhibitory gaincontrol pool. The parameters of this model have been optimized through a fit to the recent data that describe masking of a Gabor function by cosine and Gabor masks [Foley, J. M. (1994). Human luminance pattern mechanisms: masking experiments require a new model. Journal of the Optical Society of America A 11(6), 17101719]. The model achieves a good fit to the data. We also demonstrate how the concept of recruitment may accommodate a variant of this model in which excitatory and inhibitory paths share a common accelerating nonlinearity, but which include multiple channels tuned to different levels of contrast [Teo, P. C. & Heeger, D. J. (1994). Perceptual image distortion. Proceedings,
The scaling of the noscale potential and de Sitter model building
"... We propose a variant of the KKLT (A)dS flux vacuum construction which does not require an antibrane to source the volume modulus. The strategy is to find nonzero local minima of the noscale potential in the complex structure and dilaton directions in moduli space. The corresponding noscale potenti ..."
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Cited by 55 (3 self)
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We propose a variant of the KKLT (A)dS flux vacuum construction which does not require an antibrane to source the volume modulus. The strategy is to find nonzero local minima of the noscale potential in the complex structure and dilaton directions in moduli space. The corresponding noscale potential expanded about this point sources the volume modulus in the same way as does the antibrane of the KKLT construction. We exhibit explicit examples of such nonzero local minima of the noscale potential in a simple toroidal orientifold model.
A Survey on the Theorema Project
 In International Symposium on Symbolic and Algebraic Computation
, 1997
"... The Theorema project aims at extending current computer algebra systems by facilities for supporting mathematical proving. The present earlyprototype version of the Theorema software system is implemented in Mathematica 3.0. The system consists of a general higherorder predicate logic prover and ..."
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Cited by 49 (11 self)
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The Theorema project aims at extending current computer algebra systems by facilities for supporting mathematical proving. The present earlyprototype version of the Theorema software system is implemented in Mathematica 3.0. The system consists of a general higherorder predicate logic prover and a collection of special provers that call each other depending on the particular proof situations. The individual provers imitate the proof style of human mathematicians and aim at producing humanreadable proofs in natural language presented in nested cells that facilitate studying the computergenerated proofs at various levels of detail. The special provers are intimately connected with the functors that build up the various mathematical domains. 1 The Objectives of the Theorema Project The Theorema project aims at providing a uniform (logic and software) frame for computing, solving, and proving. In a simplified view, given a "knowledge base" K of formulae (and a logical / computat...
A HandwritingBased Equation Editor
, 1999
"... Current equation editing systems rely on either textbased equation description languages or on interactive construction by means of structure templates and menus. These systems are often tedious to use, even for experts, because the user is forced to "parse" the expressions mentally before ..."
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Cited by 37 (5 self)
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Current equation editing systems rely on either textbased equation description languages or on interactive construction by means of structure templates and menus. These systems are often tedious to use, even for experts, because the user is forced to "parse" the expressions mentally before they are entered. This step is not normally part of the process of writing equations on paper or on a whiteboard. We describe a prototype equation editor that is based on handwriting recognition and automatic equation parsing. It is coupled with a user interface that incorporates a set of simple procedures for correcting errors made by the automatic interpretation. Although some correction by the user is typically necessary before the formula is recognized, we have found that the system is simpler and more natural to use than systems based on specialized languages or templatebased interaction.
NEST: An environment for neural systems simulations
 In T. Plesser and V. Macho (Eds.), Forschung und wisschenschaftliches Rechnen, Beitrage zum HeinzBillingPreis 2001, Volume 58 of GWDGBericht
, 2002
"... NEST is a framework for simulating large, structured neuronal systems. It is designed to investigate the functional behavior of neuronal systems in the context of their anatomical, morphological, and electrophysiological properties. NEST aims at large networks, while maintaining an appropriate degre ..."
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Cited by 11 (3 self)
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NEST is a framework for simulating large, structured neuronal systems. It is designed to investigate the functional behavior of neuronal systems in the context of their anatomical, morphological, and electrophysiological properties. NEST aims at large networks, while maintaining an appropriate degree of biological detail. This is achieved by combining a broad range of abstraction levels in a single network simulation. Great biological detail is then maintained only at the points of interest, while the rest of the system can be modeled by more abstract components. Here, we describe the conception of NEST and illustrate its key features. We demonstrate that software design and organizational aspects were of equal importance for the success of the project. 1
Focus windows: A new technique for proof presentation
 Artificial Intelligence, Automated Reasoning and Symbolic Computation, number 2385 in LNAI
, 2002
"... ..."
Theorema 2.0: A Graphical User Interface for a Mathematical Assistant System
"... Theorema 2.0 stands for a redesign including a complete reimplementation of the Theorema system, which was originally designed, developed, and implemented by Bruno Buchberger and his Theorema group at RISC. In this paper, we present the first prototype of a graphical user interface (GUI) for the n ..."
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Cited by 6 (4 self)
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Theorema 2.0 stands for a redesign including a complete reimplementation of the Theorema system, which was originally designed, developed, and implemented by Bruno Buchberger and his Theorema group at RISC. In this paper, we present the first prototype of a graphical user interface (GUI) for the new system. It heavily relies on powerful interactive capabilities introduced in recent releases of the underlying Mathematica system, most importantly the possibility of having dynamic objects connected to interface elements like sliders, menus, checkboxes, radiobuttons and the like. All these features are fully integrated into the Mathematica programming environment and allow the implementation of a modern interface comparable to standard Javabased GUIs. 1
Spectral Factorization Of The Krylov Matrix And Convergence Of Gmres
"... Is it possible to use eigenvalues and eigenvectors to establish accurate results on GMRES performance? Existing convergence bounds, that are extensions of analysis of Hermitian solvers like CG and MINRES, provide no useful information when the coefficient matrix is almost defective. In this paper we ..."
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Cited by 6 (2 self)
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Is it possible to use eigenvalues and eigenvectors to establish accurate results on GMRES performance? Existing convergence bounds, that are extensions of analysis of Hermitian solvers like CG and MINRES, provide no useful information when the coefficient matrix is almost defective. In this paper we propose a new framework for using spectral information for convergence analysis. It is based on what we call the spectral factorization of the Krylov matrix. Using the new apparatus, we prove that two related matrices are equivalent in terms of GMRES convergence, and derive necessary conditions for the worstcase righthand side vector. We also show that for a specific family of application problems, the worstcase vector has a compact form. In addition, we present numerical data that shows that two matrices that yield the same worstcase GMRES behavior may differ significantly in their average behavior.
Adiabatic connection approach to density functional theory of electronic systems
 Int. J. Quantum Chem
"... ABSTRACT: Using recent calculations we review some wellknown aspects of density functional theory: the Hohenberg–Kohn theorems, the Kohn–Sham method, the adiabatic connection, and the approximations of local nature. Emphasis is put upon using model Hamiltonians, of which the noninteracting or the p ..."
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Cited by 6 (5 self)
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ABSTRACT: Using recent calculations we review some wellknown aspects of density functional theory: the Hohenberg–Kohn theorems, the Kohn–Sham method, the adiabatic connection, and the approximations of local nature. Emphasis is put upon using model Hamiltonians, of which the noninteracting or the physical ones are just particular cases. The model Hamiltonians allow us to produce multireference density functional theory and continuously switch to the physical system. © 2003 Wiley