Results for "Mads Almassalkhi"

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Convex inner approximation of the feeder hosting capacity limits on dispatchable demandMay 14 2019This paper presents a method to obtain a convex inner approximation that aims to improve the feasibility of optimal power flow (OPF) models in distribution feeders. For a resistive distribution network, both real and reactive power effect the node voltages ... More
Corrective dispatch of uncertain energy resources using chance-constrained receding horizon controlOct 19 2018Oct 24 2018To optimally dispatch uncertain, energy-constrained reserves, model predictive control offers a viable tool to develop an appropriate trade-off between closed-loop performance and robustness of the dispatch. Therefore, this paper investigates the uncertainty ... More
Towards network admissible optimal dispatch of flexible loads in distribution networksJul 15 2019This paper presents a computationally tractable convex, optimal power flow (OPF) formulation that is admissible with respect to voltage and current limits. This is achieved by considering bounds on the non linear terms in the power flow equations. The ... More
Optimal multi-period dispatch of distributed energy resources in unbalanced distribution feedersJun 10 2019This paper develops an efficient algorithm for the optimal dispatch of deterministic inverter-interfaced energy storage in an unbalanced distribution feeder with significant solar PV penetration.The three-phase non-convex loss-minimization problem is ... More
A Model-Predictive Control Method for Coordinating Virtual Power Plants and Packetized Resources, with Hardware-in-the-Loop ValidationJan 12 2019In this paper, we employ a bi-level control system to react to disturbances and balance power mismatch by coordinating distributed energy resources (DERs) under packetized energy management. Packetized energy management (PEM) is a novel bottom-up asynchronous ... More
The Kelly growth optimal strategy with a stop-loss ruleNov 11 2013Nov 19 2013From the Hamilton-Jacobi-Bellman equation for the value function we derive a non-linear partial differential equation for the optimal portfolio strategy (the dynamic control). The equation is general in the sense that it does not depend on the terminal ... More
Maximal regularity of the time-periodic Navier-Stokes systemAug 26 2013Time-periodic solutions to the linearized Navier-Stokes system in the $n$-dimensional whole-space are investigated. For time-periodic data in $L^q$-spaces, maximal regularity and corresponding a priori estimates for the associated time-periodic solutions ... More
A fundamental solution to the time-periodic Stokes equationsMay 15 2015Oct 31 2015The concept of a fundamental solution to the time-periodic Stokes equations in dimension $n\geq 2$ is introduced. A fundamental solution is then identified and analyzed. Integrability and pointwise estimates are established.
Existence and regularity of time-periodic solutions to the three-dimensional Navier-Stokes equationsSep 23 2013May 20 2014Existence, uniqueness, and regularity of time-periodic solutions to the Navier-Stokes equations in the three-dimensional whole-space are investigated. We consider the Navier-Stokes equations with a non-zero drift term corresponding to the physical model ... More
Atomistic theory for the damping of vibrational modes in mono-atomic gold chainsApr 29 2009Jul 31 2009We develop a computational method for evaluating the damping of vibrational modes in mono-atomic metallic chains suspended between bulk crystals under external strain. The damping is due to the coupling between the chain and contact modes and the phonons ... More
Renewal Time Points for Hawkes ProcessesJun 05 2019Jun 08 2019In the last decade Hawkes processes have received much attention as models for functional connectivity in neural spiking networks and other dynamical systems with a cascade behavior. In this paper we establish a renewal approach for analyzing this process. ... More
Two dimensional electron transport in disordered and ordered distributions of magnetic flux vorticesApr 18 1994We have considered the conductivity properties of a two dimensional electron gas (2DEG) in two different kinds of inhomogeneous magnetic fields, i.e.\ a disordered distribution of magnetic flux vortices, and a periodic array of magnetic flux vortices. ... More
Estimates of time-periodic fundamental solutions to the linearized Navier-Stokes equationsOct 28 2016Dec 12 2016Fundamental solutions to the time-periodic Stokes and Oseen linearizations of the Navier-Stokes equations in dimension $n\geq 2$ are investigated. Integrability properties and pointwise estimates are established.
Invariants of Lagrangian cobordisms via spectral numbersMay 19 2016May 24 2016We extend parts of the Lagrangian spectral invariants package recently developed by Leclercq and Zapolsky to the theory of Lagrangian cobordism developed by Biran and Cornea. This yields a new lower bound for the "cobordism metric" introduced by Cornea ... More
Strong Spin-Filtering and Spin-Valve Effects in a Molecular V-C60-V ContactMay 17 2012Motivated by the recent achievements in manipulation of C60 molecules in STM experiments, we study theoretically the structure and electronic properties of a C60 molecule in an STM-tunneljunction with a magnetic tip and magnetic adatom on a Cu(111) surface ... More
On a (no longer) new Segal algebra - a review of the Feichtinger algebraAug 16 2016Jul 25 2017Since its invention in 1979, the Feichtinger algebra has become a very useful Banach space of functions with applications in time-frequency analysis, the theory of pseudo-differential operators and several other topics. It is easily defined on locally ... More
Nonlinear acoustics: Blackstock-Crighton equations with a periodic forcing termOct 17 2017Mar 02 2018The Blackstock-Crighton equations describe the motion of a viscous, heat-conducting, compressible fluid. They are used as models for acoustic wave propagation in a medium in which both nonlinear and dissipative effects are taken into account. In this ... More
Minimal Walking TechnicolorOct 23 2007I report on our construction and analysis of the effective low energy Lagrangian for the Minimal Walking Technicolor (MWT) model. The parameters of the effective Lagrangian are constrained by imposing modified Weinberg sum rules and by imposing a value ... More
On Variational Methods for Motion Compensated InpaintingSep 21 2018We develop in this paper a generic Bayesian framework for the joint estimation of motion and recovery of missing data in a damaged video sequence. Using standard maximum a posteriori to variational formulation rationale, we derive generic minimum energy ... More
Nonlinear Wave Equation with Damping: Periodic Forcing and Non-Resonant Solutions to the Kuznetsov EquationNov 27 2016Existence of non-resonant solutions of time-periodic type are established for the Kuznetsov equation with a periodic forcing term. The equation is considered in a three-dimensional whole-space, half-space and bounded domain, and with both non-homogeneous ... More
Theory of the Eigler-swithDec 02 1993We suggest a simple model to describe the reversible field-induced transfer of a single Xe-atom in a scanning tunneling microscope, --- the Eigler-switch. The inelasticly tunneling electrons give rise to fluctuating forces on and damping of the Xe-atom ... More
On a (no longer) new Segal algebraAug 16 2016Since its invention in 1979, the Feichtinger algebra has become a very useful Banach space of functions with applications in time-frequency analysis, the theory of pseudo-differential operators and several other topics. It is easily defined on locally ... More
Renewal Time Points for Hawkes ProcessesJun 05 2019In the last decade Hawkes processes have received much attention as models for functional connectivity in neural spiking networks and other dynamical systems with a cascade behavior. In this paper we establish a renewal approach for analyzing this process. ... More
Efficient fourth order symplectic integrators for near-harmonic separable Hamiltonian systemsJan 18 2015Feb 09 2015Efficient fourth order symplectic integrators are proposed for numerical integration of separable Hamiltonian systems H(p,q)=T(p)+V(q). Symmetric splitting coefficients with five to nine stages are obtained by higher order decomposition of the simple ... More
Transmission eigenchannels from non-equilibrium Green's functionsFeb 13 2007Sep 28 2007The concept of transmission eigenchannels is described in a tight-binding nonequilibrium Green's function (NEGF) framework. A simple procedure for calculating the eigenchannels is derived using only the properties of the device subspace and quantities ... More
Time-periodic Stokes equations with inhomogeneous Dirichlet boundary conditions in a half-spaceSep 07 2018Oct 06 2018The time-periodic Stokes problem in a half-space with fully inhomogeneous right-hand side is investigated. Maximal regularity in a time-periodic Lp setting is established. A method based on Fourier multipliers is employed that leads to a decomposition ... More
On the asymptotic structure of steady Stokes and Navier-Stokes flows around a rotating two-dimensional bodySep 10 2018We establish pointwise decay estimates for the velocity field of a steady two-dimensional Stokes flow around a rotating body via a new approach rather than analysis adopted in the previous literature. The novelty is to analyze the singular behavior of ... More
A distance expanding flow on exact Lagrangian cobordism classesAug 20 2016Given an exact Lagrangian $L$ of an exact symplectic manifold $(M,d\lambda )$, Cornea and Shelukhin recently introduced a remarkable "cobordism metric" $d_c$ on the exact Lagrangian cobordism class $\mathcal{L}(L)$ of $L$. In this note we show that the ... More
Estimates of time-periodic fundamental solutions to the linearized Navier-Stokes equationsOct 28 2016Fundamental solutions to the time-periodic Stokes and Oseen linearizations of the Navier-Stokes equations in dimension $n\geq 2$ are investigated. Integrability properties and pointwise estimates are established.
A Proof Carrying Code Framework for Inlined Reference Monitors in Java BytecodeDec 14 2010We propose a light-weight approach for certification of monitor inlining for sequential Java bytecode using proof-carrying code. The goal is to enable the use of monitoring for quality assurance at development time, while minimizing the need for post-shipping ... More
Two-dimensional electron transport in the presence of magnetic flux vorticesNov 04 1994We have considered the conductivity properties of a two dimensional electron gas (2DEG) in two different kinds of inhomogeneous magnetic fields, i.e. a disordered distribution of magnetic flux vortices, and a periodic array of magnetic flux vortices. ... More
On Time-Periodic Solutions to Parabolic Boundary Value Problems of Agmon-Douglis-Nirenberg TypeMay 20 2017Oct 17 2017Time-periodic solutions to partial differential equations of parabolic type corresponding to an operator that is elliptic in the sense of Agmon-Douglis-Nirenberg are investigated. In the whole- and half-space case we construct an explicit formula for ... More
Unitarity implications of diboson resonance in the TeV region for Higgs physicsJul 03 2015We investigate the implications of a putative new resonance in the TeV region coupled to the weak bosons. By studying perturbative unitarity in longitudinal WW scattering, we find that a weakly coupled spin-1 resonance, that explains the ATLAS diboson ... More
Density and duality theorems for regular Gabor framesApr 21 2015We investigate Gabor frames on locally compact abelian groups with time-frequency shifts along non-separable, closed subgroups of the phase space. Density theorems in Gabor analysis state necessary conditions for a Gabor system to be a frame or a Riesz ... More
Light Higgs from Scalar See-Saw in TechnicolorNov 30 2012We consider a TeV scale see-saw mechanism leading to light scalar resonances in models with otherwise intrinsically heavy scalars. The mechanism can provide a 125 GeV technicolor Higgs in e.g. two-scale TC models
Discovering a Light Scalar or Pseudoscalar at The Large Hadron ColliderMar 18 2012The allowed standard model Higgs mass range has been reduced to a region between 114 and 130 GeV or above 500 GeV, at the 99% confidence level, since the Large Hadron Collider (LHC) program started. Furthermore some of the experiments at Tevatron and ... More
Sampling and periodization of generators of Heisenberg modulesNov 27 2018This paper considers generators of Heisenberg modules in the case of twisted group $C^*$-algebras of closed subgroups of locally compact abelian groups and how the restrction and/or periodization of these generators yield generators for other Heisenberg ... More
Existence of a Unique Quasi-stationary Distribution for Stochastic Reaction NetworksAug 21 2018In the setting of stochastic dynamical systems that eventually go extinct, the quasi-stationary distributions are useful to understand the long-term behavior of a system before evanescence. For a broad class of applicable continuous-time Markov processes ... More
Co-compact Gabor systems on locally compact abelian groupsNov 18 2014Apr 21 2015In this work we extend classical structure and duality results in Gabor analysis on the euclidean space to the setting of second countable locally compact abelian (LCA) groups. We formulate the concept of rationally oversampling of Gabor systems in an ... More
Probabilistic Output Analysis by Program ManipulationSep 29 2015The aim of a probabilistic output analysis is to derive a probability distribution of possible output values for a program from a probability distribution of its input. We present a method for performing static output analysis, based on program transformation ... More
Duality of Gabor frames and Heisenberg modulesJun 14 2018Sep 11 2018Given a locally compact abelian group $G$ and a closed subgroup $\Lambda$ in $G\times\widehat{G}$, Rieffel associated to $\Lambda$ a Hilbert $C^*$-module $\mathcal{E}$, known as a Heisenberg module. He proved that $\mathcal{E}$ is an equivalence bimodule ... More
Simple and efficient way of speeding up transmission calculations with $k$-point samplingMay 13 2015The transmissions as functions of energy are central for electron or phonon transport in the Landauer transport picture. We suggest a simple and computationally "cheap" post-processing scheme to interpolate transmission functions over $k$-points to get ... More
Localized edge vibrations and edge reconstruction by Joule heating in graphene nanostructuresNov 04 2009Control of the edge topology of graphene nanostructures is critical to graphene-based electronics. A means of producing atomically smooth zigzag edges using electronic current has recently been demonstrated in experiments [Jia et al., Science 323, 1701 ... More
Evolutionary reconstruction of networksNov 09 2001Can a graph specifying the pattern of connections of a dynamical network be reconstructed from statistical properties of a signal generated by such a system? In this model study, we present an evolutionary algorithm for reconstruction of graphs from their ... More
Time-periodic solutions to the Navier-Stokes equations in the three-dimensional whole-space with a non-zero drift term: Asymptotic profile at spatial infinityOct 03 2016An asymptotic expansion at spatial infinity of a weak time-periodic solution to the Navier-Stokes equations with a non-zero drift term in the three-dimensional whole-space is carried out. The asymptotic profile is explicitly identified and expressed in ... More
Time-period flow of a viscous liquid past a bodySep 30 2016Time-periodic solutions to the Navier-Stokes equations that govern the flow of a viscous liquid past a three-dimensional body moving with a time-periodic velocity are investigated. The net motion of the body over a full time-period is assumed to be non-zero. ... More
A Method for Discriminating Between Dark Matter Models and MOND Modified Inertia via Galactic Rotation CurvesOct 09 2017Mar 07 2018Dark Matter (DM) and Modified Newtonian Dynamics (MOND) models of rotationally supported galaxies lead to curves, $\mathcal{C}$, with different geometries in $(g_{\rm bar},g_{\rm tot})$-space ($g2$-space). Here $g_{\rm tot}$ is the total centripetal acceleration ... More
Investigating Dark Matter and MOND Models with Galactic Rotation Curve DataMay 27 2018We study geometries of galactic rotation curves from Dark Matter (DM) and Modified Newtonian Dynamics (MOND) models in $(g_{\rm bar},g_{\rm tot})$-space ($g2$-space) where $g_{\rm tot}$ is the total centripetal acceleration of matter in the galaxies and ... More
Reproducing formulas for generalized translation invariant systems on locally compact abelian groupsMay 20 2014Apr 21 2015In this paper we connect the well established discrete frame theory of generalized shift invariant systems to a continuous frame theory. To do so, we let $\Gamma_j$, $j \in J$, be a countable family of closed, co-compact subgroups of a second countable ... More
Probabilistic Resource Analysis by Program TransformationAug 03 2016The aim of a probabilistic resource analysis is to derive a probability distribution of possible resource usage for a program from a probability distribution of its input. We present an automated multi- phase rewriting based method to analyze programs ... More
Composite "zigzag" structures in the 1D complex Ginzburg-Landau equationApr 27 2001We study the dynamics of the one-dimensional complex Ginzburg Landau equation (CGLE) in the regime where holes and defects organize themselves into composite superstructures which we call zigzags. Extensive numerical simulations of the CGLE reveal a wide ... More
Asymmetric dark matter and the SunMar 23 2010Jun 01 2010Cold dark matter particles with an intrinsic matter-antimatter asymmetry do not annihilate after gravitational capture by the Sun and can affect its interior structure. The rate of capture is exponentially enhanced when such particles have self-interactions ... More
iTIMP: isotriplet Technicolor Interacting Massive Particle as Dark MatterNov 09 2009Dec 10 2009We suggest that a weak isotriplet composite scalar possessing an unbroken U(1) global symmetry naturally arises in technicolor models leading to an interesting type of dark matter candidate: the iTIMP. We propose explicit models of the iTIMP, study earth ... More
Probabilistic Resource Analysis by Program TransformationAug 03 2016Dec 15 2016The aim of a probabilistic resource analysis is to derive a probability distribution of possible resource usage for a program from a probability distribution of its input. We present an automated multi- phase rewriting based method to analyze programs ... More
Cosmic Sum RulesOct 29 2010May 23 2011We introduce new sum rules allowing to determine universal properties of the unknown component of the cosmic rays and show how they can be used to predict the positron fraction at energies not yet explored by current experiments and to constrain specific ... More
The Up-Shot of Inelastic Down-Scattering at CDMS-SiJan 03 2014Feb 21 2014We study dark matter that inelastically scatters and de-excites in direct detection experiments, as an interpretation of the CDMS-Si events in light of the recent LUX data. The constraints from LUX and XENON10 require the mass-splitting between the DM ... More
Delineating the conformal windowJul 09 2010Jul 20 2010We identify and characterise the conformal window in gauge theories relevant for beyond the standard model building, e.g. Technicolour, using the criteria of metric confinement and causal analytic couplings, which are known to be consistent with the phase ... More
Nonequilibrium electron-vibration coupling and conductance fluctuations in a C60-junctionSep 25 2012We investigate chemical bond formation and conductance in a molecular C60-junction under finite bias voltage using first-principles calculations based on density functional theory and nonequilibrium Green's functions (DFT-NEGF). At the point of contact ... More
Symmetries and composite dynamics for the 750 GeV diphoton excessJan 20 2016Mar 18 2016The ATLAS and CMS experiments at LHC observe small excesses of diphoton events with invariant mass around 750 GeV. Here we study the possibility of nearly parity degenerate and vector-scalar degenerate spectra as well as composite dynamics in 2 scenarios ... More
Managing Communication Latency-Hiding at Runtime for Parallel Programming Languages and LibrariesJan 18 2012This work introduces a runtime model for managing communication with support for latency-hiding. The model enables non-computer science researchers to exploit communication latency-hiding techniques seamlessly. For compiled languages, it is often possible ... More
Distribution Theory by Riemann IntegralsOct 10 2018It is the purpose of this article to outline a course that can be given to engineers looking for an understandable mathematical description of the foundations of distribution theory and the necessary functional analytic methods. Arguably, these are needed ... More
Technicolor Dark MatterDec 17 2008Dec 23 2008Dark Matter candidates are natural in Technicolor theories. We introduce a general framework allowing to predict signals of Technicolor Dark Matter at colliders and set constraints from earth based experiments such as CDMS and XENON. We show that the ... More
Gene Expression Noise Facilitates Adaptation and Drug Resistance Independently of MutationOct 28 2011Nov 16 2011We show that the effect of stress on the reproductive fitness of noisy cell populations can be modelled as first-passage time problem, and demonstrate that even relatively short-lived fluctuations in gene expression can ensure long-term survival of a ... More
Surface decorated silicon nanowires: a route to high-ZT thermoelectricsJul 13 2009Based on atomistic calculations of electron and phonon transport, we propose to use surface decorated Silicon nanowires (SiNWs) for thermoelectric applications. Two examples of surface decorations are studied to illustrate the underlying deas: Nanotrees ... More
Electron- and phonon transport in silicon nanowires: an atomistic approach to thermoelectric propertiesOct 30 2008We compute both electron- and phonon transmissions in thin disordered silicon nanowires. Our atomistic approach is based on tight-binding and empirical potential descriptions of the electronic and phononic systems, respectively. Surface disorder is modeled ... More
Field effect in stacked van der Waals heterostructures: Stacking sequence mattersAug 17 2016Stacked van der Waals (vdW) heterostructures where semi-conducting two-dimensional (2D) materials are contacted by overlayed graphene electrodes enable atomically-thin, flexible electronics. We use first-principles quantum transport simulations of graphene-contacted ... More
Gabor Duality Theory for Morita Equivalent $C^*$-algebrasMay 06 2019The duality principle for Gabor frames is one of the pillars of Gabor analysis. We establish a far-reaching generalization to Morita equivalent $C^*$-algebras where the equivalence bimodule is a finitely generated projective Hilbert $C^*$-module. These ... More
Stochastically generated turbulence with improved kinematic propertiesFeb 07 2017We present a stochastic turbulence generator based on a vorticity formulation where the generated turbulent field implicitly fulfills the kinematic constraints of an incompressible flow. The generator allows direct access to the turbulent velocity and ... More
Current-induced atomic forces in gated graphene nanoconstrictionsMay 03 2019Electronic current densities can reach extreme values in highly conducting nanostructures where constrictions limit current. For bias voltages on the 1 volt scale, the highly non-equilibrium situation can influence the electronic density between atoms, ... More
Inelastic fingerprints of hydrogen contamination in atomic gold wire systemsAug 23 2006Oct 26 2006We present series of first-principles calculations for both pure and hydrogen contaminated gold wire systems in order to investigate how such impurities can be detected. We show how a single H atom or a single H2 molecule in an atomic gold wire will affect ... More
Atomic-scale model for the contact resistance of the nickel-graphene interfaceFeb 01 2012Apr 03 2012We perform first-principles calculations of electron transport across a nickel-graphene interface. Four different geometries are considered, where the contact area, graphene and nickel surface orientations and the passivation of the terminating graphene ... More
125 GeV Higgs from a not so light Technicolor ScalarNov 06 2012Jun 05 2013Assuming that the observed Higgs-like resonance at the Large Hadron Collider is a technicolor isosinglet scalar (the technicolor Higgs), we argue that the standard model top-induced radiative corrections reduce its dynamical mass towards the desired experimental ... More
Constraining Walking and Custodial TechnicolorDec 12 2007We show how to constrain the physical spectrum of walking technicolor models via precision measurements and modified Weinberg sum rules. We also study models possessing a custodial symmetry for the S parameter at the effective Lagrangian level - custodial ... More
Simple and efficient LCAO basis sets for the diffuse states in carbon nanostructuresMar 05 2018May 16 2018We present a simple way to describe the lowest unoccupied diffuse states in carbon nanostructures in density functional theory (DFT) calculations using a minimal LCAO (linear combination of atomic orbitals) basis set. By comparing plane wave basis calculations, ... More
Conductance switching in a molecular device: the role of sidegroups and intermolecular interactioDec 09 2002We report first-principles studies of electronic transport in monolayers of Tour wires functionalized with different side groups. An analysis of the scattering states and transmission eigenchannels suggests that the functionalization does not strongly ... More
Age Dependent Hawkes ProcessJun 17 2018In the last decade, Hawkes processes have received a lot of attention as good models for functional connectivity in neural spiking networks. In this paper we consider a variant of this process, the Age Dependent Hawkes process, which incorporates individual ... More
Near-Earth supernova activity during the past 35 MyrAug 28 2017Here we combine observations of open clusters (OCs) with single- and binary population synthesis models and a Galactic potential to reconstruct the SN activity of these OCs during the past 35 Myr. We find that several OCs potentially hosting SN progenitors ... More
Asymmetric Dark Matter Models and the LHC Diphoton ExcessMar 30 2016The existence of dark matter (DM) and the origin of the baryon asymmetry are persistent indications that the SM is incomplete. More recently, the ATLAS and CMS experiments have observed an excess of diphoton events with invariant mass of about 750 GeV. ... More
The inner kernel theorem for a certain Segal algebraJun 16 2018The Segal algebra ${\textbf{S}}_{0}(G)$ is well defined for arbitrary locally compact Abelian Hausdorff (LCA) groups $G$. Despite the fact that it is a Banach space it is possible to derive a kernel theorem similar to the Schwartz kernel theorem, of course ... More
Self-organized stable pacemakers near the onset of birhythmicityNov 16 2000General amplitude equations for reaction-diffusion systems near to the soft onset of birhythmicity described by a supercritical pitchfork-Hopf bifurcation are derived. Using these equations and applying singular perturbation theory, we show that stable ... More
Flexural phonon scattering induced by electrostatic gating in grapheneSep 19 2016Graphene has an extremely high carrier mobility partly due to its planar mirror symmetry inhibiting scattering by the highly occupied acoustic flexural phonons. Electrostatic gating of a graphene device can break the planar mirror symmetry yielding a ... More
Vanilla Technicolor at Linear CollidersMar 16 2011We analyze the reach of Linear Colliders (LC)s for models of dynamical electroweak symmetry breaking. We show that LCs can efficiently test the compositeness scale, identified with the mass of the new spin-one resonances, till the maximum energy in the ... More
Heat conductance is strongly anisotropic for pristine silicon nanowiresJan 08 2009We compute atomistically the heat conductance for ultra-thin pristine silicon nanowires (SiNWs) with diameters ranging from 1 to 5 nm. The room temperature thermal conductance is found to be highly anisotropic: wires oriented along the <110> direction ... More
Fourth Lepton Family is Natural in TechnicolorMay 10 2009Imagine to discover a new fourth family of leptons at the Large Hadron Collider (LHC) but no signs of an associated fourth family of quarks. What would that imply? An intriguing possibility is that the new fermions needed to compensate for the new leptons ... More
Data Augmentation of Spectral Data for Convolutional Neural Network (CNN) Based Deep ChemometricsOct 05 2017Deep learning methods are used on spectroscopic data to predict drug content in tablets from near infrared (NIR) spectra. Using convolutional neural networks (CNNs), features are ex- tracted from the spectroscopic data. Extended multiplicative scatter ... More
Laser-like vibrational instability in rectifying molecular conductorsMar 10 2011We study the damping of molecular vibrations due to electron-hole pair excitations in donor-acceptor(D-A) type molecular rectifiers. At finite voltage additional non-equilibrium electron-hole pair excitations involving both electrodes become possible, ... More
Epistemic Temporal Logic for Information Flow SecurityAug 30 2012Temporal epistemic logic is a well-established framework for expressing agents knowledge and how it evolves over time. Within language-based security these are central issues, for instance in the context of declassification. We propose to bring these ... More
Play or science?: a study of learning and framing in crowdscience gamesOct 23 2015Crowdscience games may hold unique potentials as learning opportunities compared to games made for fun or education. They are part of an actual science problem solving process: By playing, players help scientists, and thereby interact with real continuous ... More
Modeling inelastic phonon scattering in atomic- and molecular-wire junctionsMay 19 2005Nov 30 2005Computationally inexpensive approximations describing electron-phonon scattering in molecular-scale conductors are derived from the non-equilibrium Green's function method. The accuracy is demonstrated with a first principles calculation on an atomic ... More
On the identification of pristine and defected graphene nanoribbons by phonon signatures in the electron transport characteristicsJan 09 2015Inspired by recent experiments where electron transport was measured across graphene nanoribbons (GNR) suspended between a metal surface and the tip of a scanning tunneling microscope [Koch \textit{et al}., Nat. Nanotechnol. {\bf 7}, 713 (2012)], we present ... More
Optimization over Geodesics for Exact Principal Geodesic AnalysisAug 11 2010May 02 2013In fields ranging from computer vision to signal processing and statistics, increasing computational power allows a move from classical linear models to models that incorporate non-linear phenomena. This shift has created interest in computational aspects ... More
Atomic carbon chains as spin-transmitters: an \textit{Ab initio} transport studySep 09 2009Jun 17 2010An atomic carbon chain joining two graphene flakes was recently realized in a ground-breaking experiment by Jin {\it et al.}, Phys. Rev. Lett. {\bf 102}, 205501 (2009). We present {\it ab initio} results for the electron transport properties of such chains ... More
Transport in Silicon Nanowires: Role of Radial Dopant ProfileJan 08 2008We consider the electronic transport properties of phosphorus (P) doped silicon nanowires (SiNWs). By combining ab initio density functional theory (DFT) calculations with a recursive Green's function method, we calculate the conductance distribution ... More
Higher representations on the lattice: perturbative studiesFeb 06 2008We present analytical results to guide numerical simulations with Wilson fermions in higher representations of the colour group. The ratio of $\Lambda$ parameters, the additive renormalization of the fermion mass, and the renormalization of fermion bilinears ... More
Modeling of inelastic transport in one-dimensional metallic atomic wiresNov 04 2004Inelastic effects in electron transport through nano-sized devices are addressed with a method based on nonequilibrium Green's functions (NEGF) and perturbation theory to infinite order in the electron-vibration coupling. We discuss the numerical implementation ... More
Colliding clusters and dark matter self-interactionsAug 15 2013Jan 17 2014When a dark matter halo moves through a background of dark matter particles, self-interactions can lead to both deceleration and evaporation of the halo and thus shift its centroid relative to the collisionless stars and galaxies. We study the magnitude ... More
Chromospheric emission of planet candidate systems - a way to identify false positivesAug 28 2016Aug 30 2016It has been hypothesized that the presence of closely orbiting giant planets is associated with enhanced chromospheric emission of their host stars. The main cause for such a relation would likely be enhanced dynamo action induced by the planet. We present ... More
X-ray Lines from Dark Matter: The Good, The Bad, and The UnlikelyMar 06 2014May 26 2014We consider three classes of dark matter (DM) models to account for the recently observed 3.5 keV line: metastable excited state DM, annihilating DM, and decaying DM. We study two examples of metastable excited state DM. The first, millicharged composite ... More
ABS-NET: Fully Decentralized Runtime Adaptation for Distributed ObjectsOct 17 2013We present a formalized, fully decentralized runtime semantics for a core subset of ABS, a language and framework for modelling distributed object-oriented systems. The semantics incorporates an abstract graph representation of a network infrastructure, ... More
Knowledge Formation and Inter-Game Transfer With Classical and Quantum PhysicsAug 26 2016In order to facilitate an intuitive understanding of classical physics concepts we have developed Potential Penguin - a game where players manipulate the landscape around a sliding penguin in order to control its movement. The learning goal of Potential ... More