Results for "Tor Arne Johansen"

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Fault-Tolerant Control Allocation: an Unknown Input Observer based approachJun 23 2013This paper focuses on the use of unknown input observers for detection and isolation of actuator and effector faults with control reconfiguration in overactuated systems. The control allocation actively uses input redundancy in order to make relevant ... More
Multi-agent formation control for circumnavigation of dynamic shapesMay 07 2018Sep 22 2018The problem of multi-agent formation control for target tracking is considered in this paper. The target is an irregular dynamic shape approximated by a circle with moving centre and varying radius. It is assumed that there are n agents and one of them ... More
Cooperative decentralized circumnavigation with application to algal bloom trackingMar 14 2019Harmful algal blooms occur frequently and deteriorate water quality. A reliable method is proposed in this paper to track algal blooms using a set of autonomous surface robots. A satellite image indicates the existence and initial location of the algal ... More
Regret Analysis of the Anytime Optimally Confident UCB AlgorithmMar 29 2016May 06 2016I introduce and analyse an anytime version of the Optimally Confident UCB (OCUCB) algorithm designed for minimising the cumulative regret in finite-armed stochastic bandits with subgaussian noise. The new algorithm is simple, intuitive (in hindsight) ... More
Regret Analysis of the Finite-Horizon Gittins Index Strategy for Multi-Armed BanditsNov 18 2015May 27 2016I analyse the frequentist regret of the famous Gittins index strategy for multi-armed bandits with Gaussian noise and a finite horizon. Remarkably it turns out that this approach leads to finite-time regret guarantees comparable to those available for ... More
Towards autonomous ocean observing systems using Miniature Underwater Gliders with UAV deployment and recovery capabilitiesFeb 08 2019This paper presents preliminary results towards the development of an autonomous ocean observing system using Miniature Underwater Gliders (MUGs) that can operate with the support of Unmanned Aerial Vehicles (UAVs) and Unmanned Surface Vessels (USVs) ... More
R-hadron at ATLAS -Discovery Prospects and PropertiesJan 30 2007Jan 31 2007R-hadrons are massive, meta-stable particles predicted in several Super- symmetry scenarios. Studies exploring the discovery potential of R-hadrons at the ATLAS detector have mainly focused on gluino R-hadrons. These studies have shown that gluino R-hadrons ... More
On Flow Equivalence of Sofic ShiftsOct 10 2012The flow equivalence of sofic shifts is examined using results about the structure of the corresponding covers. A canonical cover generalising the left Fischer cover to arbitrary sofic shifts is introduced and used to prove that the left Krieger cover ... More
New Permutation Trinomials From Niho Exponents over Finite Fields with Even CharacteristicJun 12 2016In this paper, a class of permutation trinomials of Niho type over finite fields with even characteristic is further investigated. New permutation trinomials from Niho exponents are obtained from linear fractional polynomials over finite fields, and it ... More
New Binomial Bent Function over the Finite Fields of Odd CharacteristicJul 20 2009The $p$-ary function $f(x)$ mapping $\mathrm{GF}(p^{4k})$ to $\mathrm{GF}(p)$ given by $f(x)={\rm Tr}_{4k}\big(x^{p^{3k}+p^{2k}-p^k+1}+x^2\big)$ is proven to be a weakly regular bent function and the exact values of its Walsh transform coefficients are ... More
Cleaning up the neighborhood: A full classification for adversarial partial monitoringMay 23 2018Partial monitoring is a generalization of the well-known multi-armed bandit framework where the loss is not directly observed by the learner. We complete the classification of finite adversarial partial monitoring to include all games, solving an open ... More
Refined Lower Bounds for Adversarial BanditsMay 24 2016We provide new lower bounds on the regret that must be suffered by adversarial bandit algorithms. The new results show that recent upper bounds that either (a) hold with high-probability or (b) depend on the total lossof the best arm or (c) depend on ... More
Interior-point algorithms for convex optimization based on primal-dual metricsNov 08 2014We propose and analyse primal-dual interior-point algorithms for convex optimization problems in conic form. The families of algorithms we analyse are so-called short-step algorithms and they match the current best iteration complexity bounds for primal-dual ... More
On the Equation $x^{2^l+1}+x+a=0$ over $\mathrm{GF}(2^k)$ (Extended Version)Oct 22 2008Oct 07 2009In this paper, the polynomials $P_a(x)=x^{2^l+1}+x+a$ with $a\in\mathrm{GF}(2^k)$ are studied. New criteria for the number of zeros of $P_a(x)$ in $\mathrm{GF}(2^k)$ are proved. In particular, a criterion for $P_a(x)$ to have exactly one zero in $\mathrm{GF}(2^k)$ ... More
Several Classes of Permutation Trinomials From Niho ExponentsDec 28 2016Motivated by recent results on the constructions of permutation polynomials with few terms over the finite field $\mathbb{F}_{2^n}$, where $n$ is a positive even integer, we focus on the construction of permutation trinomials over $\mathbb{F}_{2^n}$ from ... More
Computing accurate Horner form approximations to special functions in finite precision arithmeticAug 13 2015In various applications, computers are required to compute approximations to univariate elementary and special functions such as $\exp$ and $\arctan$ to modest accuracy. This paper proposes a new heuristic for automating the design of such implementations. ... More
Linear dependence of bivariate Minimal Support and LR B-splines over LR-meshesNov 12 2018The focus on locally refined spline spaces has grown rapidly in recent years due to the need in Isogeoemtric analysis (IgA) of spline spaces with local adaptivity: a property not offered by the strict regular structure of tensor product B-spline spaces. ... More
Magnetization in 2+1 dimensional QED at Finite Temperature and DensityOct 24 1994We consider Dirac fermions moving in a plane with a static homogeneous magnetic field orthogonal to the plane. We calculate the effective action at finite temperature and density. The magnetization is derived and it is shown that the fermion gas exhibits ... More
Finite genome size can halt Muller's ratchetSep 21 2001We study the accumulation of deleterious mutations in a haploid, asexually reproducing population, using analytical models and computer simulations. We find that Muller's ratchet can come to a halt in small populations as a consequence of a finite genome ... More
Weighted inequalities and uncertainty principles for the $\boldsymbol{(k,a)}$-generalized Fourier transformFeb 17 2015Jan 15 2016We obtain several versions of the Hausdorff-Young and Hardy-Littlewood inequalities for the $(k,a)$-generalized Fourier transform recently investigated at length by Ben Sa\"i d, Kobayashi, and {\O} rsted. We also obtain a number of weighted inequalities ... More
Large Stock Market Price Drawdowns Are OutliersOct 03 2000Jul 25 2001Drawdowns are essential aspects of risk assessment in investment management. They offer a more natural measure of real market risks than the variance or other cumulants of daily (or some other fixed time scale) distributions of returns. Here, we extend ... More
Evaluation of the quantitative prediction of a trend reversal on the Japanese stock market in 1999Feb 03 2000In January 1999, the authors published a quantitative prediction that the Nikkei index should recover from its 14 year low in January 1999 and reach $\approx 20500$ a year later. The purpose of the present paper is to evaluate the performance of this ... More
Download relaxation dynamics on the WWW following newspaper publication of URLJul 23 1999Jul 24 1999A few key properties of the World-Wide-Web (WWW) has been established indicating the lack of any characteristic scales for the WWW, both in its topology and in its dynamics. Here, we report an experiment which quantifies another power law describing the ... More
Analysis of the Forward Search using some new results for martingales and empirical processesFeb 02 2016The Forward Search is an iterative algorithm for avoiding outliers in a regression analysis suggested by Hadi and Simonoff (J. Amer. Statist. Assoc. 88 (1993) 1264-1272), see also Atkinson and Riani (Robust Diagnostic Regression Analysis (2000) Springer). ... More
Significance of log-periodic precursors to financial crashesJun 26 2001We clarify the status of log-periodicity associated with speculative bubbles preceding financial crashes. In particular, we address Feigenbaum's [2001] criticism and show how it can be rebuked. Feigenbaum's main result is as follows: ``the hypothesis ... More
Harvesting the decay energy of $^{26}$Al to drive lightning discharge in protoplanetary discsAug 17 2017Chondrules in primitive meteorites likely formed by recrystallisation of dust aggregates that were flash-heated to nearly complete melting. Chondrules may represent the building blocks of rocky planetesimals and protoplanets in the inner regions of protoplanetary ... More
Generalized Complexity of ALC SubsumptionMay 03 2012The subsumption problem with respect to terminologies in the description logic ALC is EXPTIME-complete. We investigate the computational complexity of fragments of this problem by means of allowed Boolean operators. Hereto we make use of the notion of ... More
3-Colourability of Dually Chordal Graphs in Linear TimeJun 01 2012Nov 13 2012A graph G is dually chordal if there is a spanning tree T of G such that any maximal clique of G induces a subtree in T. This paper investigates the Colourability problem on dually chordal graphs. It will show that it is NP-complete in case of four colours ... More
Lorentz-covariant quantum transport and the origin of dark energyMar 19 2010May 04 2011A possible explanation for the enigma of dark energy, responsible for about 76 % of the mass-energy of the universe, is obtained by requiring only that the rigorous continuity equation (the Boltzmann transport equation) for quanta propagating through ... More
Principes locaux-globaux pour certaines fibrations en torseurs sous un toreMay 03 2013Jan 11 2015Let $k$ be a number field and let $T$ be a $k$-torus. Consider a fibration in torsors under $T$, i.e. a morphism $f: X \to \mathbb{P}^1_k$ from a smooth, projective $k$-variety $X$ to $\mathbb{P}^1_k$ such that the generic fibre $X_\eta \to \eta$ is a ... More
Proof of Riemann's zeta-hypothesisSep 30 2008Oct 14 2013Make an exponential transformation in the integral formulation of Riemann's zeta-function zeta(s) for Re(s) > 0. Separately, in addition make the substitution s -> 1 - s and then transform back to s again using the functional equation. Using residue calculus, ... More
Colliding Singularities in F-theory and Phase TransitionsOct 16 1996Oct 27 1996We study F-theory on elliptic threefold Calabi-Yau near colliding singularities. We demonstrate that resolutions of those singularities generically correspond to transitions to phases characterized by new tensor multiplets and enhanced gauge symmetry. ... More
Keynesian Economics After AllJul 15 2011It is demonstrated that the US economy has on the long-term in reality been governed by the Keynesian approach to economics independent of the current official economical policy. This is done by calculating the two-point correlation function between the ... More
Almost Everywhere Convergence of the inverse Jacobi Transform and Endpoint Results for a Disc MultiplierJan 03 2011Jul 06 2011We introduce a maximal operator for the natural analogue of the disc multiplier in the framework of Jacobi analysis and determine the mapping properties of said maximal operator, including weak type endpoint results. In particular we obtain sharp information ... More
On a Class of Non-Integrable Multipliers for the Jacobi TransformAug 18 2011We show that a bounded function $m$ on $\R$ not necessarily integrable at infinity may still yield $L^p$-bounded convolution operators for the Jacobi transform if the nontangential boundary values of $\omega m$ along the edges of a certain strip in $\C$ ... More
Protoplanetary Disk Turbulence Driven by the Streaming Instability: Non-Linear Saturation and Particle ConcentrationFeb 23 2007We present simulations of the non-linear evolution of streaming instabilities in protoplanetary disks. The two components of the disk, gas treated with grid hydrodynamics and solids treated as superparticles, are mutually coupled by drag forces. We find ... More
SensIs - Underwater acoustic network for ice-monitoringApr 08 2016Routing for low latency underwater acoustic network-communication is investigated. The application is monitoring of ice-threats to offshore operations in the Arctic - to provide warnings that enable operators to react to such threats. The scenario produces ... More
Well-posedness of space and time dependent transport equations on a networkJun 26 2015This article is concerned with the study of weak solutions of a linear transport equation on a bounded domain with coupled boundary data for general non smooth space and time dependent velocity fields. The existence of solutions, its uniqueness and the ... More
Finite-time singularity in the dynamics of the world population, economic and financial indicesFeb 05 2000Dec 19 2001Contrary to common belief, both the Earth's human population and its economic output have grown faster than exponential, i.e., in a super-Malthusian mode, for most of the known history. These growth rates are compatible with a spontaneous singularity ... More
Large financial crashesApr 15 1997Jun 16 1997We propose that large stock market crashes are analogous to critical points studied in statistical physics with log-periodic correction to scaling. We extend our previous renormalization group model of stock market prices prior to and after crashes [D. ... More
Modeling the Stock Market prior to large crashesNov 05 1998We propose that the minimal requirements for a model of stock market price fluctuations should comprise time asymmetry, robustness with respect to connectivity between agents, ``bounded rationality'' and a probabilistic description. We also compare extensively ... More
Hardy--Littlewood inequalities for the Heckman--Opdam transformJan 26 2015We establish Hardy--Littlewood inequalities for the Heckman--Opdam transform associated to a general root datum $(\mathfrak{a},\Sigma,m)$ that generalizes an analogous result for the spherical Fourier transform on a Riemannian symmetric space of the non-compact ... More
Protoplanetary Disk Turbulence Driven by the Streaming Instability: Linear Evolution and Numerical MethodsFeb 23 2007We present local simulations that verify the linear streaming instability that arises from aerodynamic coupling between solids and gas in protoplanetary disks. This robust instability creates enhancements in the particle density in order to tap the free ... More
Frozen time in hyperbolic spacetime motionJul 25 2011Aug 24 2011According to the Lorentz transformation and clearly seen from the Minkowski diagram, hyperbolic spacetime motion of a test object relative to a stationary reference frame can be performed in a specific way such that time becomes frozen in the moving frame ... More
A short note on the Radon-Riesz property for continuous Banach space valued functionsJun 25 2015Jun 26 2015We present a generalization of the Radon-Riesz property to sequences of continuous functions with values in uniformly convex and uniformly smooth Banach spaces.
On Local Integrability Conditions Of Jet GroupoidsAug 10 2007A Jet groupoid R_q over a manifold X is a special Lie groupoid consisting of q-jets of local diffeomorphisms from X to X. As a subbundle of the q-th order jet bundle of the trivial bundle X times X, a jet groupoid can be considered as a nonlinear system ... More
Niho Bent Functions and Subiaco/Adelaide HyperovalsOct 17 2012In this paper, the relation between binomial Niho bent functions discovered by Dobbertin et al. and o-polynomials that give rise to the Subiaco and Adelaide classes of hyperovals is found. This allows to expand the class of bent functions that corresponds ... More
$m$-Sequences of Different Lengths with Four-Valued Cross CorrelationDec 21 2007{\bf Abstract.} Considered is the distribution of the cross correlation between $m$-sequences of length $2^m-1$, where $m$ is even, and $m$-sequences of shorter length $2^{m/2}-1$. The infinite family of pairs of $m$-sequences with four-valued cross correlation ... More
Modeling Deep Learning Accelerator Enabled GPUsNov 19 2018Feb 21 2019The efficacy of deep learning has resulted in its use in a growing number of applications. The Volta graphics processor unit (GPU) architecture from NVIDIA introduced a specialized functional unit, the "tensor core", that helps meet the growing demand ... More
Experiments in vortex avalanchesFeb 03 2004Avalanche dynamics is found in many phenomena spanning from earthquakes to the evolution of species. It can be also found in vortex matter when a type II superconductor is externally driven, for example, by increasing the magnetic field. Vortex avalanches ... More
On the Feeding Zone of Planetesimal Formation by the Streaming InstabilityJul 22 2014The streaming instability is a promising mechanism to overcome the barriers in direct dust growth and lead to the formation of planetesimals. Most previous studies of the streaming instability, however, were focused on a local region of a protoplanetary ... More
Approximate implicitization using linear algebraMay 27 2016In this paper we consider a family of algorithms for approximate implicitization of rational parametric curves and surfaces. The main approximation tool in all of the approaches is the singular value decomposition, and they are therefore well suited to ... More
Concentration and Confidence for Discrete Bayesian Sequence PredictorsJun 29 2013Bayesian sequence prediction is a simple technique for predicting future symbols sampled from an unknown measure on infinite sequences over a countable alphabet. While strong bounds on the expected cumulative error are known, there are only limited results ... More
Free Lunch for Optimisation under the Universal DistributionAug 16 2016Function optimisation is a major challenge in computer science. The No Free Lunch theorems state that if all functions with the same histogram are assumed to be equally probable then no algorithm outperforms any other in expectation. We argue against ... More
Online Learning to Rank with FeaturesOct 05 2018We introduce a new model for online ranking in which the click probability factors into an examination and attractiveness function and the attractiveness function is a linear function of a feature vector and an unknown parameter. Only relatively mild ... More
On the discovery of Birkhoff's theoremAug 22 2005Sep 06 2005Birkhoff showed in 1923 that the Schwarzschild solution for the metric from a point particle was also valid in the a priori non-static case as long as the spherical symmetry was maintained. This theorem was actually discovered and published two years ... More
Convergence and Rates for Fixed-Interval Multiple-Track Smoothing Using $k$-Means Type OptimizationJun 08 2015May 04 2016We address the task of estimating multiple trajectories from unlabelled data. This problem arises in many settings, one could think of the construction of maps of transport networks from passive observation of travellers, or the reconstruction of the ... More
Spin-pumping and Enhanced Gilbert Damping in Thin Magnetic Insulator FilmsMar 20 2013Precessing magnetization in a thin film magnetic insulator pumps spins into adjacent metals; however, this phenomenon is not quantitatively understood. We present a theory for the dependence of spin-pumping on the transverse mode number and in-plane wave ... More
Equivalence between pathbreadth and strong pathbreadthSep 17 2018We say that a given graph $G = (V, E)$ has \emph{pathbreadth} at most $\rho$, denoted $\pb(G) \leq \rho$, if there exists a Roberston and Seymour's path decomposition where every bag is contained in the $\rho$-neighbourhood of some vertex. Similarly, ... More
The Measurement Problem Is the "Measurement" ProblemOct 10 2018Physics builds on two tenets: On the one hand, statements are expressed in formal languages. On the other, these statements are to be tested against experience. Observers are the nexus between experience and the account thereof. Whether this very account ... More
Finite Dimensional Representations of the Projective Modular GroupOct 19 2006We study finite dimensional representations of the projective modular group. Various explicit dimension formulas are given.
Carlitz Rank and Index of Permutation PolynomialsNov 19 2016Carlitz rank and index are two important measures for the complexity of a permutation polynomial $f(x)$ over the finite field $\F_q$. In particular, for cryptographic applications we need both, a high Carlitz rank and a high index. In this article we ... More
Extensions of smoothing via taut stringsMar 20 2008Jan 29 2009Suppose that we observe independent random pairs $(X_1,Y_1)$, $(X_2,Y_2)$, >..., $(X_n,Y_n)$. Our goal is to estimate regression functions such as the conditional mean or $\beta$--quantile of $Y$ given $X$, where $0<\beta <1$. In order to achieve this ... More
Branching form of the resolvent at threshold for multi-dimensional discrete LaplaciansAug 12 2016Mar 15 2017We consider the discrete Laplacian on $\mathbb Z^d$, and compute asymptotic expansions of its resolvent around thresholds embedded in continuous spectrum as well as those at end points. We prove that the resolvent has a square-root branching if $d$ is ... More
Kick Motions for the NAO Robot using Dynamic Movement PrimitivesJun 02 2016In this paper, we present the probably first application of the popular \emph{Dynamic Movement Primitives (DMP)} approach to the domain of soccer-playing humanoid robots. DMPs are known for their ability to imitate previously demonstrated motions as well ... More
Counterintuitive properties of the fixation time in network-structured populationsJun 17 2014Apr 22 2015Evolutionary dynamics on graphs can lead to many interesting and counterintuitive findings. We study the Moran process, a discrete time birth-death process, that describes the invasion of a mutant type into a population of wild-type individuals. Remarkably, ... More
Microscopic Calibration and Validation of Car-Following Models -- A Systematic ApproachMar 19 2014Calibration and validation techniques are crucial in assessing the descriptive and predictive power of car-following models and their suitability for analyzing traffic flow. Using real and generated floating-car and trajectory data, we systematically ... More
Online traffic state estimation based on floating car dataDec 21 2010Besides the traditional data collection by stationary detectors, recent advances in wireless and sensor technologies have promoted new potentials for a vehicle-based data collection and local dissemination of information. By means of microscopic traffic ... More
Fermion loops, loop cancellation and density correlations in two dimensional Fermi systemsMay 18 1998May 19 1998We derive explicit results for fermion loops with an arbitrary number of density vertices in two dimensions at zero temperature. The 3-loop is an elementary function of the three external momenta and frequencies, and the N-loop can be expressed as a linear ... More
Spin transport in mesoscopic rings with inhomogeneous spin-orbit couplingNov 03 2006Oct 26 2007We revisit the problem of electron transport through mesoscopic rings with spin-orbit (SO) interaction. In the well-known path-integral approach, the scattering states for a quasi-1D ring with quasi-1D leads can be expressed in terms of spinless electrons ... More
Shot noise in ferromagnet--normal metal systemsMay 15 2001Aug 14 2002A semiclassical theory of the low frequency shot noise in ferromagnet - normal metal systems is formulated. Non-collinear magnetization directions of the ferromagnetic leads, arbitrary junctions and the elastic and inelastic scattering regimes are considered. ... More
Statistical Speech Model Description with VMF Mixture ModelAug 02 2018In this paper, we present the LSF parameters by a unit vector form, which has directional characteristics. The underlying distribution of this unit vector variable is modeled by a von Mises-Fisher mixture model (VMM). With the high rate theory, the optimal ... More
Instability of resonances under Stark perturbationsApr 16 2018Let $H^{\varepsilon}=-\frac{d^2}{dx^2}+\varepsilon x +V$, $\varepsilon\geq0$, on $L^2(\mathbf{R})$. Let $V=\sum_{k=1}^Nc_k|\psi_k\rangle\langle\psi_k|$ be a rank $N$ operator, where the $\psi_k\in L^2(\mathbf{R})$ are real, compactly supported, and even. ... More
Uniqueness and stability result for Cauchy's equation of motion for a certain class of hyperelastic materialsFeb 04 2014Feb 05 2014We consider Cauchy's equation of motion for hyperelastic materials. The solution of this nonlinear initial-boundary value problem is the vector field which discribes the displacement which a particle of this material perceives when exposed to stress and ... More
UBVRI photometric comparison sequences for symbiotic stars. IIMar 15 2001We present accurate and deep UBVRI photometric sequences for an additional 20 symbiotic stars. As for the 20 targets of Paper I, the sequences extend over wide brightness and color ranges, and are suited to cover both quiescence and outburst phases. The ... More
Dynamics of cosmic strings and springs; a covariant formulationApr 20 1993A general family of charge-current carrying cosmic string models is investigated. In the special case of circular configurations in arbitrary axially symmetric gravitational and electromagnetic backgrounds the dynamics is determined by simple point particle ... More
A Domain-Specific Language for Rich Motor Skill ArchitecturesFeb 26 2013Model-driven software development is a promising way to cope with the complexity of system integration in advanced robotics, as it already demonstrated its benefits in domains with comparably challenging system integration requirements. This paper reports ... More
Quantum Spin Tomography in Ferromagnet-Normal ConductorsFeb 12 2010We present a theory for a complete reconstruction of non-local spin correlations in ferromagnet-normal conductors. This quantum spin tomography is based on cross correlation measurements of electric currents into ferromagnetic terminals with controllable ... More
Spin and Charge Pumping by Ferromagnetic-Superconductor Order ParametersApr 24 2004Sep 06 2004We study transport in ferromagnetic-superconductor/normal-metal systems. It is shown that charge and spin currents are pumped from ferromagnetic superconductors into adjacent normal metals by adiabatic changes in the order parameters induced by external ... More
Computing the Rank and a Small Nullspace Basis of a Polynomial MatrixMay 11 2005We reduce the problem of computing the rank and a nullspace basis of a univariate polynomial matrix to polynomial matrix multiplication. For an input n x n matrix of degree d over a field K we give a rank and nullspace algorithm using about the same number ... More
Homotopy theory of C*-algebrasNov 30 2008In this work we construct from ground up a homotopy theory of C*-algebras. This is achieved in parallel with the development of classical homotopy theory by first introducing an unstable model structure and second a stable model structure. The theory ... More
Family complexity and cross-correlation measure for families of binary sequencesAug 21 2014We study the relationship between two measures of pseudorandomness for families of binary sequences: family complexity and cross-correlation measure introduced by Ahlswede et al.\ in 2003 and recently by Gyarmati et al., respectively. More precisely, ... More
Logarithmic good reduction of abelian varietiesDec 08 2015Oct 23 2016Let $K$ be a field which is complete for a discrete valuation. We prove a logarithmic version of the N\'eron-Ogg-Shafarevich criterion: if $A$ is an abelian variety over $K$ which is cohomologically tame, then $A$ has good reduction in the logarithmic ... More
Magnetostrictive behaviour of thin superconducting disksJul 14 2003Flux-pinning-induced stress and strain distributions in a thin disk superconductor in a perpendicular magnetic field is analyzed. We calculate the body forces, solve the magneto-elastic problem and derive formulas for all stress and strain components, ... More
Shape Distortion by Irreversible Flux-Pinning-Induced MagnetostrictionDec 08 1997Exact analytical results are obtained for the flux-pinning-induced magnetostriction in cylindrical type-II superconductors placed in parallel magnetic field. New modes of irreversible deformation are found: In contrast to the circular cylinder where shape ... More
Mapping Self-Organized Criticality onto CriticalityNov 28 1994We present a general conceptual framework for self-organized criticality (SOC), based on the recognition that it is nothing but the expression, ''unfolded'' in a suitable parameter space, of an underlying {\em unstable} dynamical critical point. More ... More
Degenerate Feedback Loops in Recommender SystemsFeb 27 2019Mar 03 2019Machine learning is used extensively in recommender systems deployed in products. The decisions made by these systems can influence user beliefs and preferences which in turn affect the feedback the learning system receives - thus creating a feedback ... More
Surface Compression Using Dynamic Color PalettesJan 19 2019Off-chip memory traffic is a major source of power and energy consumption on mobile platforms. A large amount of this off-chip traffic is used to manipulate graphics framebuffer surfaces. To cut down the cost of accessing off-chip memory, framebuffer ... More
Corrigendum to New Generalized Cyclotomic Binary Sequences of Period $p^2$Jul 09 2018New generalized cyclotomic binary sequences of period $p^2$ are proposed in this paper, where $p$ is an odd prime. The sequences are almost balanced and their linear complexity is determined. The result shows that the proposed sequences have very large ... More
Thermal entanglement in a molecular chainSep 29 2008We investigate entanglement in a linear chain of $N$ polar molecules coupled by dipole interaction. In our model, nearest neighbour interaction predominate, and we compute entanglement with the help of a two-party correlation entanglement measure. We ... More
Spontaneous-Symmetry-Breaking Mechanism of Adiabatic PumpingJul 02 2004May 26 2005We consider heterostructures consisting of regions with a continuous symmetry in contact with regions wherein the symmetry is spontaneously broken. The low-frequency dynamics of the corresponding order parameter are shown to induce nonequilibrium transport, ... More
An Open-Source Microscopic Traffic SimulatorDec 22 2010We present the interactive Java-based open-source traffic simulator available at In contrast to most closed-source commercial simulators, the focus is on investigating fundamental issues of traffic dynamics rather than simulating ... More
Calibration and validation of models describing the spatiotemporal evolution of congested traffic patternsAug 10 2010We propose a quantitative approach for calibrating and validating key features of traffic instabilities based on speed time series obtained from aggregated data of a series of neighboring stationary detectors. We apply the proposed criteria to historic ... More
Phase Diagram of a Lattice Microemulsion Model in Two DimensionsJul 06 1992The phase diagram of a lattice microemulsion model proposed by Ciach, H{\o}ye and Stell is studied using mean-field theory and Monte Carlo simulations. Surfactant directional degrees of freedom are summed out exactly before mean-field theory is applied, ... More
Nonnegative HMM for Babble Noise Derived from Speech HMM: Application to Speech EnhancementSep 16 2017Deriving a good model for multitalker babble noise can facilitate different speech processing algorithms, e.g. noise reduction, to reduce the so-called cocktail party difficulty. In the available systems, the fact that the babble waveform is generated ... More
Open Source Automatic Speech Recognition for GermanJul 26 2018High quality Automatic Speech Recognition (ASR) is a prerequisite for speech-based applications and research. While state-of-the-art ASR software is freely available, the language dependent acoustic models are lacking for languages other than English, ... More
Tropical covers of curves and their moduli spacesMar 26 2013We define the tropical moduli space of covers of a tropical line in the plane as weighted abstract polyhedral complex, and the tropical branch map recording the images of the simple ramifications. Our main result is the invariance of the degree of the ... More
Fixation probabilities in populations under demographic fluctuationsAug 31 2017We study the fixation probability of a mutant type when introduced into a resident population. As opposed to the usual assumption of constant pop- ulation size, we allow for stochastically varying population sizes. This is implemented by a stochastic ... More
Almost all random graphs are amplifiers of selection for Birth-death dynamics, but suppressors of selection for death-Birth dynamicsApr 15 2015We analyze evolutionary dynamics on graphs, where the nodes represent individuals of a population. The links of a node describe which other individuals can be displaced by the offspring of the individual on that node. Amplifiers of selection are graphs ... More
Logarithmic good reduction of abelian varietiesDec 08 2015Let $K$ be a field which is complete for a discrete valuation. We prove a logarithmic version of the N\'eron-Ogg-Shafarevich criterion: if $A$ is an abelian variety over $K$ which is cohomologically tame, then $A$ has good reduction in the logarithmic ... More