Results for "Kristoffer H. Madsen"

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Ergodicity-breaking reveals time optimal economic behavior in humansJun 11 2019Jun 12 2019Ergodicity describes an equivalence between the expectation value and the time average of observables. Applied to human behaviour, ergodic theory reveals how individuals should tolerate risk in different environments. To optimise wealth over time, agents ... More
An explicit formula for optimal portfolios in complete Wiener driven markets: a functional Itô calculus approachOct 17 2016Dec 29 2017We consider a standard optimal investment problem in a complete financial market driven by a Wiener process and derive an explicit formula for the optimal portfolio process in terms of the vertical derivative from functional It^o calculus. An advantage ... More
Constructive martingale representation in functional Itô calculus: a local martingale extensionNov 28 2016Dec 10 2018The constructive martingale representation theorem of functional It\^o calculus is extended, from the space of square integrable martingales, to the space of local martingales. The setting is that of an augmented filtration generated by a Wiener process. ... More
A regular equilibrium solves the extended HJB systemNov 09 2016Mar 15 2019Control problems not admitting the dynamic programming principle are known as time-inconsistent. The game-theoretic approach is to interpret such problems as intrapersonal dynamic games and look for subgame perfect Nash equilibria. A fundamental result ... More
Deep Convolutional Neural Networks for Interpretable Analysis of EEG Sleep Stage ScoringOct 02 2017Sleep studies are important for diagnosing sleep disorders such as insomnia, narcolepsy or sleep apnea. They rely on manual scoring of sleep stages from raw polisomnography signals, which is a tedious visual task requiring the workload of highly trained ... More
Short Selling with Margin Risk and Recall RiskMar 28 2019Short sales are regarded as negative purchases in textbook asset pricing theory. In reality, however, the symmetry between purchases and short sales is broken by a variety of costs and risks peculiar to the latter. We formulate an optimal stopping model ... More
On Finding Equilibrium Stopping Times for Time-Inconsistent Markovian ProblemsSep 15 2017Dec 04 2018Standard Markovian optimal stopping problems are consistent in the sense that the first entrance time into the stopping set is optimal for each initial state of the process. Clearly, the usual concept of optimality cannot in a straightforward way be applied ... More
On time-inconsistent stopping problems and mixed strategy stopping timesApr 19 2018May 07 2018A game-theoretic framework for time-inconsistent stopping problems where the time-inconsistency is due to the consideration of a non-linear function of an expected reward is developed. A class of mixed strategy stopping times that allows the agents in ... More
Nonparametric Modeling of Dynamic Functional Connectivity in fMRI DataJan 04 2016Jun 08 2016Dynamic functional connectivity (FC) has in recent years become a topic of interest in the neuroimaging community. Several models and methods exist for both functional magnetic resonance imaging (fMRI) and electroencephalography (EEG), and the results ... More
On a common generalization of Koszul duality and tilting equivalenceJul 19 2010We propose a new definition of Koszulity for graded algebras where the degree zero part has finite global dimension, but is not necessarily semi-simple. The standard Koszul duality theorems hold in this setting. We give an application to algebras arising ... More
The Koszul dual of a weakly Koszul moduleFeb 02 2007We study the so-called weakly Koszul modules and characterise their Koszul duals. We show that the (adjusted) associated graded module of a weakly Koszul module exactly determines the homology modules of the Koszul dual. We give an example of a quasi-Koszul ... More
Probabilistic PARAFAC2Jun 21 2018The PARAFAC2 is a multimodal factor analysis model suitable for analyzing multi-way data when one of the modes has incomparable observation units, for example because of differences in signal sampling or batch sizes. A fully probabilistic treatment of ... More
Phonon transport unveils the prevalent point defects in GaNDec 21 2017Determining the types and concentrations of vacancies present in intentionally doped GaN is a notoriously difficult and long-debated problem. Here we use an unconventional approach, based on thermal transport modeling, to determine the prevalence of vacancies ... More
Higher-order Rewriting for Executable Compiler SpecificationsFeb 18 2011In this paper we outline how a simple compiler can be completely specified using higher order rewriting in all stages: parsing, analysis/optimization, and code emission, specifically using the system for a small declarative language called ... More
Improved Path Planning by Tightly Combining Lattice-based Path Planning and Numerical Optimal ControlMar 19 2019Mar 25 2019This paper presents a unified optimization-based path planning approach to efficiently compute locally optimal solutions to advanced path planning problems. The approach is motivated by first showing that a lattice-based path planner can be cast and analyzed ... More
High order finite difference methods for the wave equation with non-conforming grid interfacesSep 25 2015We use high order finite difference methods to solve the wave equation in the second order form. The spatial discretization is performed by finite difference operators satisfying a summation-by-parts property. The focus of this work is on the numerical ... More
Discretization of Linear Problems in Banach Spaces: Residual Minimization, Nonlinear Petrov-Galerkin, and Monotone Mixed MethodsNov 13 2015Jul 29 2018This work presents a comprehensive discretization theory for abstract linear operator equations in Banach spaces. The fundamental starting point of the theory is the idea of residual minimization in dual norms, and its inexact version using discrete dual ... More
Three-dimensional Brownian motion and the golden ratio ruleMar 12 2013Let $X=(X_t)_{t\ge0}$ be a transient diffusion process in $(0,\infty)$ with the diffusion coefficient $\sigma>0$ and the scale function $L$ such that $X_t\rightarrow\infty$ as $t\rightarrow \infty$, let $I_t$ denote its running minimum for $t\ge0$, and ... More
Tracking the Consumption Junction: Temporal Dependencies between Articles and Advertisements in Dutch NewspapersMar 27 2019Historians have regularly debated whether advertisements can be used as a viable source to study the past. Their main concern centered on the question of agency. Were advertisements a reflection of historical events and societal debates, or were ad makers ... More
On the stability of solitary water waves with a point vortexNov 19 2018This paper investigates the stability of traveling wave solutions to the free boundary Euler equations with a submerged point vortex. We prove that sufficiently small-amplitude waves with small enough vortex strength are conditionally orbitally stable. ... More
On the propagation of singularities for a class of linearised hybrid inverse problemsAug 02 2017For a general formulation of linearised hybrid inverse problems in impedance tomography, the qualitative properties of the solutions are analysed. Using an appropriate scalar pseudo-differential formulation, the problems are shown to permit propagating ... More
almaBTE: a solver of the space-time dependent Boltzmann transport equation for phonons in structured materialsApr 13 2017almaBTE is a software package that solves the space- and time-dependent Boltzmann transport equation for phonons, using only ab-initio calculated quantities as inputs. The program can predictively tackle phonon transport in bulk crystals and alloys, thin ... More
Towards end-to-end optimisation of functional image analysis pipelinesOct 13 2016The study of neurocognitive tasks requiring accurate localisation of activity often rely on functional Magnetic Resonance Imaging, a widely adopted technique that makes use of a pipeline of data processing modules, each involving a variety of parameters. ... More
Adaptive Smoothing in fMRI Data Processing Neural NetworksOct 02 2017Functional Magnetic Resonance Imaging (fMRI) relies on multi-step data processing pipelines to accurately determine brain activity; among them, the crucial step of spatial smoothing. These pipelines are commonly suboptimal, given the local optimisation ... More
Giga-Hertz quantized charge pumping in bottom gate defined InAs nanowire quantum dotsSep 04 2015Semiconducting nanowires (NWs) are a versatile, highly tunable material platform at the heart of many new developments in nanoscale and quantum physics. Here, we demonstrate charge pumping, i.e., the controlled transport of individual electrons through ... More
Scalable Group Level Probabilistic Sparse Factor AnalysisDec 14 2016Many data-driven approaches exist to extract neural representations of functional magnetic resonance imaging (fMRI) data, but most of them lack a proper probabilistic formulation. We propose a group level scalable probabilistic sparse factor analysis ... More
Ergodicity-breaking reveals time optimal economic behavior in humansJun 11 2019Ergodicity describes an equivalence between the expectation value and the time average of observables. Applied to human behaviour, ergodic theory reveals how individuals should tolerate risk in different environments. To optimise wealth over time, agents ... More
Homological stability of diffeomorphism groupsMar 19 2012Sep 04 2012In this paper we prove a stability theorem for block diffeomorphisms of 2d-dimensional manifolds that are connected sums of S^d x S^d. Combining this with a recent theorem of S. Galatius and O. Randal-Williams and Morlet's lemma of disjunction, we determine ... More
Spin(7)-manifolds with three-torus symmetryApr 15 2011Metrics of exceptional holonomy are vacuum solutions to the Einstein equation. In this paper we describe manifolds with holonomy contained in Spin(7) preserved by a three-torus symmetry in terms of tri-symplectic geometry of four-manifolds. These complement ... More
Invariant strong KT geometry on four-dimensional solvable Lie groupsNov 03 2009A strong KT (SKT) manifold consists of a Hermitian structure whose torsion three-form is closed. We classify the invariant SKT structures on four-dimensional solvable Lie groups. The classification includes solutions on groups that do not admit compact ... More
The stable moduli space of Riemann surfaces: Mumford's conjectureDec 23 2002Jul 14 2004The main result of this paper amounts to a complete evaluation of the integral cohomological structure of the stable mapping class group. In particular it verifies the conjecture of D.Mumford about the rational cohomology of the stable mapping class group. ... More
On bounds of homological dimensions in Nakayama algebrasOct 12 2017Let $A$ be a Nakayama algebra with $n$ simple modules and a simple module $S$ of even projective dimension $m$. Choose $m$ minimal such that a simple $A$-module with projective dimension $2m$ exists, then we show that the global dimension of $A$ is bounded ... More
The odd side of torsion geometryJul 12 2012Dec 10 2012We introduce and study a notion of `Sasaki with torsion structure' (ST) as an odd-dimensional analogue of K\"ahler with torsion geometry (KT). These are normal almost contact metric manifolds that admit a unique compatible connection with 3-form torsion. ... More
Closed forms and multi-moment mapsOct 29 2011We extend the notion of multi-moment map to geometries defined by closed forms of arbitrary degree. We give fundamental existence and uniqueness results and discuss a number of essential examples, including geometries related to special holonomy. For ... More
Toric geometry of Spin(7)-manifoldsOct 30 2018Nov 01 2018We study $\mathrm{Spin}(7)$-manifolds with an effective multi-Hamiltonian action of a four-torus. On an open dense set, we provide a Gibbons-Hawking type ansatz that describes such geometries in terms of a symmetric $4\times4$-matrix of functions. This ... More
The 2018 X-ray and Radio Outburst of Magnetar XTE J1810-197Feb 22 2019Mar 15 2019We present the earliest X-ray observations of the 2018 outburst of XTE J1810-197, the first outburst since its 2003 discovery as the prototypical transient and radio-emitting anomalous X-ray pulsar (AXP). The Monitor of All-sky X-ray Image (MAXI) detected ... More
Oxygen Ordering Superstructures and Structural Phase Diagram of YBa_2Cu_3O_{6+x} Studied by Hard X-ray DiffractionJun 16 1999High energy x-ray diffraction is used to investigate the bulk oxygen ordering properties of YBa_2Cu_3O_{6+x}. Superstructures of Cu-O chains aligned along the b axis and ordered with periodicity ma, along the a axis have been observed. For $x < 0.62$ ... More
Functional form of the generalized gradient approximation for exchange: The PBE$α$ functionalSep 15 2006Nov 14 2006A new functional form for the exchange enhancement in the generalized gradient approximation within density functional theory is given. The functional form satisfies the constraints used to construct the Perdew-Burke-Ernzerhof (PBE) functional but can ... More
Low Rank Approximation of Binary Matrices: Column Subset Selection and GeneralizationsNov 05 2015Apr 20 2017Low rank matrix approximation is an important tool in machine learning. Given a data matrix, low rank approximation helps to find factors, patterns and provides concise representations for the data. Research on low rank approximation usually focus on ... More
Filtrations in abelian categories with a tilting object of homological dimension twoJul 20 2010We consider filtrations of objects in an abelian category $\catA$ induced by a tilting object $T$ of homological dimension at most two. We define three disjoint subcategories with no maps between them in one direction, such that each object has a unique ... More
Patience of Matrix GamesJun 08 2012For matrix games we study how small nonzero probability must be used in optimal strategies. We show that for nxn win-lose-draw games (i.e. (-1,0,1) matrix games) nonzero probabilities smaller than n^{-O(n)} are never needed. We also construct an explicit ... More
A Rotating-Frame Perspective on High-Harmonic Generation of Circularly Polarized LightFeb 23 2016We employ a rotating frame of reference to elucidate high-harmonic generation of circularly polarized light by bicircular driving fields. In particular, we show how the experimentally observed circular components of the high-harmonic spectrum can be directly ... More
Cohomological Comparison TheoremMay 06 2014If $f$ is an idempotent in a ring $\Lambda$, then we find sufficient \linebreak conditions which imply that the cohomology rings $\oplus_{n\ge 0}Ext^n_{\Lambda}(\Lambda/{\br},\Lambda/{\br})$ and \linebreak $\oplus_{n\ge 0}Ext^n_{f\Lambda f}(f\Lambda f/f{\br} ... More
Effects of core space and excitation levels on ground-state correlation and photoionization dynamics of Be and NeNov 26 2018We explore the effects of correlation on the ground-state energies and on photoionization dynamics in atomic Be and Ne. We apply the time-dependent restricted-active-space self-consistent-field method for several excitation schemes and active orbital ... More
WISE Discovery of Low Metallicity Blue Compact Dwarf GalaxiesJun 23 2011We report two new low metallicity blue compact dwarf galaxies (BCDs), WISEP J080103.93+264053.9 (hereafter W0801+26) and WISEP J170233.53+180306.4 (hereafter W1702+18), discovered using the Wide-field Infrared Survey Explorer (WISE). We identified these ... More
Variability in the Near-Infrared Synchrotron Emission From Cassiopeia AJun 03 2016We present multi-epoch Ks band imaging of the supernova remnant Cassiopeia A (Cas A). The morphology of the emission in this band is generally diffuse and filamentary, consistent with synchrotron radiation observed at radio wavelengths. However, in one ... More
Quantitative analysis of quantum dot dynamics and emission spectra in cavity quantum electrodynamicsOct 28 2012Dec 04 2012We present detuning-dependent spectral and decay-rate measurements to study the difference between spectral and dynamical properties of single quantum dots embedded in micropillar and photonic-crystal cavities. For the micropillar cavity, the dynamics ... More
Temperature dependence of an Efimov resonance in $^{39}\mathrm{K}$Jul 13 2018Nov 27 2018Ultracold atomic gases are an important testing ground for understanding few-body physics. In particular, these systems enable a detailed study of the Efimov effect. We use ultracold $^{39}\mathrm{K}$ to investigate the temperature dependence of an Efimov ... More
Time-inconsistent stochastic control: solving the extended HJB system is a necessary condition for regular equilibriaNov 09 2016Time-inconsistent stochastic control is a game-theoretic generalization of standard stochastic control, with well-known applications in economics and finance. One of the most important results of standard (time-consistent) stochastic control is the characterization ... More
A regular equilibrium solves the extended HJB systemNov 09 2016Dec 11 2018Control problems not admitting the dynamic programming principle are known as time-inconsistent. The game-theoretic approach is to interpret such problems as intrapersonal dynamic games and look for subgame perfect Nash equilibria. A fundamental result ... More
An explicit formula for optimal portfolios in complete Wiener driven markets: a functional Itô calculus approachOct 17 2016The optimal investment problem is one of the most important problems in mathematical finance. The main contribution of the present paper is an explicit formula for the optimal portfolio process. Our optimal investment problem is that of maximizing the ... More
Intrinsic spectral blueshifts in rapidly rotating stars?Sep 12 2003Spectroscopic radial velocities for several nearby open clusters suggest that spectra of (especially earlier-type) rapidly rotating stars are systematically blueshifted by 3 km/s or more, relative to the spectra of slowly rotating ones. Comparisons with ... More
Optimal Stopping of a Brownian Bridge with an Uncertain Pinning TimeFeb 26 2019We consider the problem of optimally stopping a Brownian bridge with an uncertain pinning time so as to maximise the value of the process upon stopping. Adopting a Bayesian approach, we consider a general prior distribution of the pinning time and allow ... More
Best Practices for Administering Concept InventoriesApr 25 2014There are a plethora of concept inventories in physics available for faculty to use, but it is not always clear exactly why you would use these tests, or how you should administer them and interpret the results. These multiple-choice research-based tests ... More
Nuclear-Motion Effects in Attosecond Transient Absorption Spectroscopy of MoleculesFeb 20 2015Apr 15 2015We investigate the characteristic effects of nuclear motion on attosecond transient absorption spectra in molecules by calculating the spectrum for different model systems. Two models of the hydrogen molecular ion are considered: one where the internuclear ... More
Mid-Infrared Selection of AGN with the Wide-Field Infrared Survey Explorer. I. Characterizing WISE-Selected AGN in COSMOSMay 03 2012The Wide-field Infrared Survey Explorer (WISE) is an extremely capable and efficient black hole finder. We present a simple mid-infrared color criterion, W1-W2 \geq 0.8 (i.e., [3.4]-[4.6] \geq 0.8, Vega), which identifies 61.9 \pm 5.4 AGN candidates per ... More
Constructive martingale representation using Functional Itô Calculus: a local martingale extensionNov 28 2016The constructive martingale representation theorem and the vertical derivative of Functional It\^o Calculus are extended, from the space of square integrable martingales, to a space of local martingales. The relevant filtration is the augmented filtration ... More
Solitary gravity-capillary water waves with point vorticesMar 20 2015Nov 02 2015We construct small-amplitude solitary traveling gravity-capillary water waves with a finite number of point vortices along a vertical line, on finite depth. This is done using a local bifurcation argument. The properties of the resulting waves are also ... More
A two-phase stochastic programming approach to biomass supply planning for combined heat and power plantsOct 25 2018Due to the new carbon neutral policies, many district heating operators start operating their combined heat and power (CHP) plants using different types of biomass instead of fossil fuel. The contracts with the biomass suppliers are negotiated months ... More
High-throughput exploration of alloying as design strategy for thermoelectricsAug 14 2015We explore a material design strategy to optimize the thermoelectric power factor. The approach is based on screening the band structure changes upon a controlled volume change. The methodology is applied to the binary silicides and germanides. We first ... More
Comparing the performance of LDA and GGA functionals in predicting the lattice thermal conductivity of semiconductor materials: the case of AlAsNov 15 2018In this contribution we assess the performance of two different exchange-correlation functionals in the first-principle prediction of the lattice thermal conductivity of bulk semiconductors, namely the local density approximation (LDA) and the Perdew-Burke-Ernzerhof ... More
BoltzTraP. A code for calculating band-structure dependent quantitiesFeb 08 2006A program for calculating the semi-classic transport coefficients is described. It is based on a smoothed Fourier interpolation of the bands. From this analytical representation we calculate the derivatives necessary for the transport distributions. The ... More
Compact Toroidal Ion Trap Design and OptimizationJul 14 2010We present the design of a new type of compact toroidal, or "halo", ion trap. Such traps may be useful for mass spectrometry, studying small Coulomb cluster rings, quantum information applications, or other quantum simulations where a ring topology is ... More
Bayesian regional flood frequency analysis for large catchmentsFeb 26 2018Mar 02 2018Regional flood frequency analysis is commonly applied in situations where there exists insufficient data at a location for a reliable estimation of flood quantiles. We develop a Bayesian hierarchical modeling framework for a regional analysis of data ... More
Charge order in Magnetite. An LDA+$U$ studyDec 21 2004The electronic structure of the monoclinic structure of Fe$_3$O$_4$ is studied using both the local density approximation (LDA) and the LDA+$U$. The LDA gives only a small charge disproportionation, thus excluding that the structural distortion should ... More
Interface of the polarizable continuum model of solvation with semi-empirical methods in the GAMESS programMar 19 2013May 22 2013An interface between semi-empirical methods and the polarized continuum model (PCM) of solvation successfully implemented into GAMESS following the approach by Chudinov et al (Chem. Phys. 1992, 160, 41). The interface includes energy gradients and is ... More
New Measurements of the Motion of the Zodiacal DustMay 26 2004Using the Wisconsin H-Alpha Mapper (WHAM), we have measured at high spectral resolution and high signal-to-noise the profile of the scattered solar Mg I 5184 absorption line in the zodiacal light. The observations were carried out toward 49 directions ... More
Wavelength Shifts in Solar-Type SpectraSep 09 2004Spectral-line displacements away from the wavelengths naively expected from the Doppler shift caused by stellar radial motion may originate as convective shifts (correlated velocity and brightness patterns in the photosphere), as gravitational redshifts, ... More
A Quark-Antiquark Condensate in Three-Dimensional QCDMar 16 1998Jul 08 1998Three-dimensional lattice QCD is studied by Monte Carlo simulations within the quenched approximation. At zero temperature a quark-antiquark condensate is observed in the limit of vanishing quark masses. The condensate vanishes continuously at the finite-temperature ... More
Time series analysis in Astronomy: limits and potentialitiesOct 15 2004In this paper we consider the problem of the limits concerning the physical information that can be extracted from the analysis of one or more time series (light curves) typical of astrophysical objects. On the basis of theoretical considerations and ... More
The Configuration Model for Partially Directed GraphsMar 17 2015The configuration model was originally defined for undirected networks and has recently been extended to directed networks. Many empirical networks are however neither undirected nor completely directed, but instead usually partially directed meaning ... More
Modeling temporal fluctuations in avalanching systemsJul 22 2008We demonstrate how to model the toppling activity in avalanching systems by stochastic differential equations (SDEs). The theory is developed as a generalization of the classical mean field approach to sandpile dynamics by formulating it as a generalization ... More
h: A Plank for Higher-order Attribute Contraction SchemesNov 09 2017We present and formalize h, a core (or "plank") calculus that can serve as the foundation for several compiler specification languages, notably CRSX (Combinatory Reductions Systems with eXtensions), HACS (Higher-order Attribute Contraction Schemes), and ... More
Integrative clustering of high-dimensional data with joint and individual clusters, with an application to the Metabric studyOct 31 2014When measuring a range of different genomic, epigenomic, transcriptomic and other variables, an integrative approach to analysis can strengthen inference and give new insights. This is also the case when clustering patient samples, and several integrative ... More
Surface Waves in Almost Incompressible Elastic MaterialsSep 16 2013A recent study shows that the classical theory concerning accuracy and points per wavelength is not valid for surface waves in almost incompressible elastic materials. The grid size must instead be proportional to $(\frac{\mu}{\lambda})^{(1/p)}$ to achieve ... More
A stochastic theory for temporal fluctuations in self-organized critical systemsOct 22 2007Jul 22 2008A stochastic theory for the toppling activity in sandpile models is developed, based on a simple mean-field assumption about the toppling process. The theory describes the process as an anti-persistent Gaussian walk, where the diffusion coefficient is ... More
Traveling water waves with critical layersAug 19 2015We establish the existence of small-amplitude uni- and bimodal steady periodic gravity waves with an affine vorticity distribution. The solutions describe waves with critical layers and an arbitrary number of crests and troughs in each minimal period. ... More
Combining Vision, Machine Learning and Automatic Control to Play the Labyrinth GameFeb 01 2016The labyrinth game is a simple yet challenging platform, not only for humans but also for control algorithms and systems. The game is easy to understand but still very hard to master. From a system point of view, the ball behaviour is in general easy ... More
Optimal Prediction of the Last-Passage Time of a Transient DiffusionDec 26 2013We identify the integrable stopping time $\tau_*$ with minimal $L^1$-distance to the last-passage time $\gamma_z$ to a given level $z>0$, for an arbitrary non-negative time-homogeneous transient diffusion $X$. We demonstrate that $\tau_*$ is in fact the ... More
Sympathetic Cooling of Trapped Cd+ IsotopesDec 14 2001We sympathetically cool a trapped 112Cd+ ion by directly Doppler-cooling a 114Cd+ ion in the same trap. This is the first demonstration of optically addressing a single trapped ion being sympathetically cooled by a different species ion. Notably, the ... More
First-principles quantitative prediction of the lattice thermal conductivity in random semiconductor alloys: the role of force-constant disorderDec 07 2017The standard theoretical understanding of the lattice thermal conductivity, $\kappa_{\ell}$, of semiconductor alloys assumes that mass disorder is the most important source of phonon scattering. In contrast, we show that the hitherto neglected contribution ... More
BoltzTraP2, a program for interpolating band structures and calculating semi-classical transport coefficientsDec 21 2017BoltzTraP2 is a software package for calculating a smoothed Fourier expression of periodic functions and the Onsager transport coefficients for extended systems using the linearized Boltzmann transport equation. It uses only the band and $k$-dependent ... More
On the Construction of Jointly Superregular Lower Triangular Toeplitz MatricesApr 26 2016Apr 27 2016Superregular matrices have the property that all of their submatrices, which can be full rank are so. Lower triangular superregular matrices are useful for e.g., maximum distance separable convolutional codes as well as for (sequential) network codes. ... More
Strong-field approximation for Coulomb explosion of H_2^+ by short intense laser pulsesApr 19 2007We present a simple quantum mechanical model to describe Coulomb explosion of H$_2^+$ by short, intense, infrared laser pulses. The model is based on the length gauge version of the molecular strong-field approximation and is valid for pulses shorter ... More
ExB mean flows in finite ion temperature plasmasApr 14 2016Aug 24 2016The impact of ion pressure dynamics on E x B mean flows is investigated. Three stresses in addition to the Reynolds stress are shown to modify the E x B mean flow. These additional terms in the stress tensor all require ion pressure fluctuations. Quasi-linear ... More
High Order Finite Difference Schemes for the Elastic Wave Equation in Discontinuous MediaSep 23 2013Finite difference schemes for the simulation of elastic waves in materi- als with jump discontinuities are presented. The key feature is the highly accurate treatment of interfaces where media discontinuities arise. The schemes are constructed using finite ... More
Angular Momentum of Electromagnetic Radiation. Fundamental physics applied to the radio domain for innovative studies of space and development of new concepts in wireless communicationsMay 02 2009In this diploma thesis we study the characteristics of electromagnetic fields carrying orbital angular momentum (OAM) by analyzing and utilizing results achieved in optics and then apply them to the radio domain to enable innovative radio studies of space ... More
Multiple Model-Free KnockoffsDec 12 2018Dec 20 2018Model-free knockoffs is a recently proposed technique for identifying covariates that is likely to have an effect on a response variable. The method is an efficient method to control the false discovery rate in hypothesis tests for separate covariates. ... More
Optimal dividends and capital injection under dividend restrictionsFeb 17 2019We study a singular stochastic control problem faced by the owner of an insurance company that dynamically pays dividends and raises capital in the presence of the restriction that the surplus process must be above a given dividend payout barrier in order ... More
Multiple Model-Free KnockoffsDec 12 2018Mar 28 2019Model-free knockoffs is a recently proposed technique for identifying covariates that is likely to have an effect on a response variable. The method is an efficient method to control the false discovery rate in hypothesis tests for separate covariates. ... More
Traveling gravity water waves with critical layersAug 19 2015Dec 09 2016We establish the existence of small-amplitude uni- and bimodal steady periodic gravity waves with an affine vorticity distribution, using a bifurcation argument that differs slightly from earlier theory. The solutions describe waves with critical layers ... More
Melting transitions in biomembranesApr 02 2019We investigated melting transitions in biological membranes in their native state that include their membrane proteins. These membranes originated from \textit{E. coli}, \textit{B. subtilis}, lung surfactant and nerve tissue from the spinal cord of several ... More
Approximation Techniques for Stochastic Analysis of Biological SystemsJan 22 2019There has been an increasing demand for formal methods in the design process of safety-critical synthetic genetic circuits. Probabilistic model checking techniques have demonstrated significant potential in analyzing the intrinsic probabilistic behaviors ... More
Optimized Orthogonal Basis Tight Binding. Application to IronApr 18 2011The formal link between the linear combination of atomic orbitals approach to density functional theory and two-center Slater-Koster tight-binding models is used to derive an orthogonal $d$-band tight-binding model for iron with only two fitting parameters. ... More
Ab initio lattice thermal conductivity of bulk and thin-film $α$-Al$\mathrm{_2}$O$\mathrm{_3}$Jun 22 2018Aug 28 2018The thermal conductivities ($\kappa$) of bulk and thin-film $\alpha$-Al$_2$O$_3$ are calculated from first principles using both the local density approximation (LDA), and the generalized gradient approximation (GGA) to exchange and correlation. The room ... More
Comparison of the Green-Kubo and homogeneous non-equilibrium molecular dynamics methods for calculating thermal conductivityMar 16 2017Jun 01 2017Different molecular dynamics methods like the direct method, the Green-Kubo (GK) method and homogeneous non-equilibrium molecular dynamics (HNEMD) method have been widely used to calculate lattice thermal conductivity ($\kappa_\ell$). While the first ... More
STAMINA: STochastic Approximate Model-checker for INfinite-state AnalysisJun 01 2019Stochastic model checking is a technique for analyzing systems that possess probabilistic characteristics. However, its scalability is limited as probabilistic models of real-world applications typically have very large or infinite state space. This paper ... More
Long-memory effects in linear-response models of Earth's temperature and implications for future global warmingMay 22 2013A linearized energy-balance model for global temperature is formulated, featuring a scale-free long-range memory (LRM) response and stochastic forcing representing the influence on the ocean heat reservoir from atmospheric weather systems. The model is ... More
Asymptotic distribution of principal component scores for pervasive, high-dimensional eigenvectorsJan 13 2014Jun 01 2015Plots of scores from principal component analysis are a popular approach to visualize and explore high-dimensional genetic data. However, the inconsistency of the high-dimensional eigenvectors has discredited classical principal component analysis and ... More
Electronic structure and transport in CsBi$_4$Te$_6$Apr 12 2006The band structure of the novel low-temperature thermoelectric material, \CBT, is calculated and analyzed using the semi-classic transport equations. It is shown that to obtain a quantitative agreement with measured transport properties a band gap of ... More