Results for "Quintin N. Meier"

total 74111took 0.15s
Charged domain walls in improper ferroelectric hexagonal manganites and gallatesJun 16 2018Jul 04 2018Ferroelectric domain walls are attracting broad attention as atomic-scale switches, diodes and mobile wires for next-generation nanoelectronics. Charged domain walls in improper ferroelectrics are particularly interesting as they offer multifunctional ... More
A dynamical magnetic field accompanying the motion of ferroelectric domain wallsApr 12 2019The recently proposed dynamical multiferroic effect describes the generation of magnetization from temporally varying electric polarization. Here, we show that the effect can lead to a magnetic field at moving ferroelectric domain walls, where the rearrangement ... More
Synchrotron Constraints on a Hybrid Cosmic-Ray and Thermally-Driven Galactic WindApr 13 2009Jan 13 2010Cosmic rays and magnetic fields can substantially impact the launching of large-scale galactic winds. Many researchers have investigated the role of cosmic rays; our group previously showed that a cosmic-ray and thermally-driven wind could explain soft ... More
Small Seifert fibered surgery on hyperbolic pretzel knotsOct 29 2012Jul 23 2013We complete the classification of hyperbolic pretzel knots admitting Seifert fibered surgeries. This is the final step in understanding all exceptional surgeries on hyperbolic pretzel knots. We also present results toward similar classifications for non-pretzel ... More
Enumeration in Incremental FPT-TimeApr 20 2018Aug 27 2018In this paper, we study the relationship of parametrised enumeration complexity classes defined by Creignou et al. (MFCS 2013). Specifically, we introduce two hierarchies (IncFPTa and CapIncFPTa) of enumeration complexity classes for incremental fpt-time ... More
Second harmonic generation on incommensurate structures: The case of multiferroic MnWO4Aug 17 2010A comprehensive analysis of optical second harmonic generation (SHG) on an incommensurate (IC) magnetically ordered state is presented using multiferroic MnWO4 as model compound. Two fundamentally different SHG contributions coupling to the primary IC ... More
Spectral Sequences in String TopologyJan 27 2010Aug 08 2015In this paper, we investigate the behaviour of the Serre spectral sequence with respect to the algebraic structures of string topology in generalized homology theories, specificially with the Chas-Sullivan product and the corresponding coproduct and module ... More
A high-energy density antiferroelectric made by interfacial electrostatic engineeringDec 22 2018Dielectric capacitors hold a tremendous advantage for energy storage due to their fast charge/discharge times and stability in comparison to batteries and supercapacitors. A key limitation to today's dielectric capacitors, however, is the low storage ... More
New model of axion monodromy inflation and its cosmological implicationsDec 14 2014Jun 11 2016We propose a new realization of axion monodromy inflation in which axion monodromy arises from torsional cycles in a type IIB compactification. A class of monomial potentials is obtained with specific values for the power index. Moreover, the inflaton ... More
Searching for features of a string-inspired inflationary model with cosmological observationsJul 20 2015Jan 04 2016The latest Planck results show a power deficit in the temperature anisotropies near $\ell \approx 20$ in the cosmic microwave background (CMB). This observation can hardly be explained within the standard inflationary $\Lambda$-cold-dark-matter ($\Lambda$CDM) ... More
Evidence for interacting dark energy from BOSSDec 08 2014Feb 23 2017The result presented by the BOSS-SDSS Collaboration measuring the baryon acoustic oscillations of the Lyman-$\alpha$ forest from high-redshift quasars indicates a $2.5\sigma$ departure from the standard $\Lambda$-cold-dark-matter model. This is the first ... More
An Alternative Between Non-unique and Negative Yamabe Solutions to the Conformal Formulation of the Einstein Constraint EquationsJun 05 2013The conformal method has been effective for parametrizing solutions to the Einstein constraint equations on closed 3-manifolds. However, it is still not well-understood; for example, existence of solutions to the conformal equations for zero or negative ... More
Generalized Solutions to Semilinear Elliptic PDE with Applications to the Lichnerowicz EquationDec 01 2011Mar 18 2013In this article we investigate the existence of a solution to a semilinear, elliptic, partial differential equation with distributional coefficients and data. The problem we consider is a generalization of the Lichnerowicz equation that one encounters ... More
Fibrancy of Partial Model CategoriesAug 12 2014We investigate fibrancy conditions in the Thomason model structure on the category of small categories. In particular, we show that the category of weak equivalences of a partial model category is fibrant. Furthermore, we describe connections to calculi ... More
The cohomology of right angled Artin groups with group ring coefficientsJan 15 2004Feb 27 2004We give an explicit formula for the cohomology of a right angled Artin group with group ring coefficients in terms of the cohomology of its defining flag complex.
A neuronal dynamics study on a neuromorphic chipMar 10 2017Neuronal firing activities have attracted a lot of attention since a large population of spatiotemporal patterns in the brain is the basis for adaptive behavior and can also reveal the signs for various neurological disorders including Alzheimer's, schizophrenia, ... More
Analysis of a three flavor neutrino oscillation fit to recent Super-Kamiokande dataOct 07 1999Nov 03 1999We have analyzed the most recent available Super-Kamiokande data in a three flavor neutrino oscillation model. We have here neglected possible matter effects and performed a fit to atmospheric and solar Super-Kamiokande data. We have investigated a large ... More
The Association of Jet Production with Geometrically Thick Accretion Flows and Black Hole RotationOct 12 2000A model is presented in which the strongest radio-emitting jet outflows are produced in black hole systems when the accretion is a geometrically thick ($H/R \sim 1$) inflow ({\it e.g.}, ADAF, CDAF) {\em and} if the black hole is rotating. For galactic ... More
Grand Unification of AGN and the Accretion and Spin ParadigmsAug 26 1999While attempts to unify certain classes of AGN using orientation and environmental effects have been successful, it is widely recognized that intrinsic properties of the accreting black hole system also must play a role in determining the appearance of ... More
C*-algebras associated to shift spacesAug 03 2008These are some notes I wrote for the summer school "Symbolic dynamics and homeomorphisms of the Cantor set" at the University of Copenhagen, 23 - 27 June 2008. The notes contain the definition of the C*-algebra associated to a shift space and some basic ... More
Eigenspaces of the Spin Dirac operator over S^3Mar 21 2011Mar 23 2011We calculate the spectrum and a basis of eigenvectors for the Spin Dirac operator over the standard 3-sphere. For the spectrum, we use the method of Hitchin which we transfer to quaternions and explain in more detail. The eigenbasis (in terms of polynomials) ... More
Orbit equivalence of higher-rank graphsMar 17 2019We study the notions of continuous orbit equivalence and eventual one-sided conjugacy of finitely-aligned higher-rank graphs and two-sided conjugacy of row-finite higher-rank graphs with finitely many vertices and no sinks or sources. We show that there ... More
Thermodynamics and Spin Tunneling Dynamics in Ferric Wheels with Excess SpinJul 02 2001We study theoretically the thermodynamic properties and spin dynamics of a class of magnetic rings closely related to ferric wheels, antiferromagnetic ring systems, in which one of the Fe (III) ions has been replaced by a dopant ion to create an excess ... More
Spinc Dirac operators over the flat 3-torusMar 02 2011Apr 17 2011The aim of this paper is to study a possible "boundary phenomenon" for Spinc Dirac operators in a special case. If you parametrise Spinc Dirac operators by a family of connections on a Spinc 4-manifold with boundary, this boundary inherits also a family ... More
Unconventional order-disorder phase transition in improper ferroelectric hexagonal manganitesJul 30 2017The improper ferroelectricity in YMnO$_3$ and related hexagonal manganites is known to cause topologically protected ferroelectric domains that give rise to rich and diverse physical phenomena. The local structure and structural coherence across the transition, ... More
Unconventional order-disorder phase transition in improper ferroelectric hexagonal manganitesJul 30 2017Apr 11 2018The improper ferroelectricity in YMnO$_3$ and other related multiferroic hexagonal manganites are known to cause topologically protected ferroelectric domains that give rise to rich and diverse physical phenomena. The local structure and structural coherence ... More
Chapter 34 - Every Moment Counts: Synchrophasors for Distribution Networks with Variable ResourcesAug 08 2014Historically, with mostly radial power distribution and one-way power flow, it was only necessary to evaluate the envelope of design conditions, e.g., peak loads or fault currents, rather than continually observe the operating state. But the growth of ... More
On Hong and Szymanski's description of the primitive-ideal space of a graph algebraDec 09 2015May 03 2019In 2004, Hong and Szymanski gave a complete description of the primitive-ideal space of the C*-algebra of a directed graph. This article details a slightly different approach, in the simpler context of row-finite graphs with no sources, obtaining an explicit ... More
Ultra-low material pixel layers for the Mu3e experimentOct 06 2016The upcoming Mu3e experiment will search for the charged lepton flavour violating decay of a muon at rest into three electrons. The maximal energy of the electrons is 53 MeV, hence a low material budget is a key performance requirement for the tracking ... More
SIMMUNE, a tool for simulating and analyzing immune system behaviorMar 28 1999We present a new approach to the simulation and analysis of immune system behavior. The simulations that can be done with our software package called SIMMUNE are based on immunological data that describe the behavior of immune system agents (cells, molecules) ... More
Nonsingular bouncing cosmologies in light of BICEP2Apr 16 2014Aug 18 2014We confront various nonsingular bouncing cosmologies with the recently released BICEP2 data and investigate the observational constraints on their parameter space. In particular, within the context of the effective field approach, we analyze the constraints ... More
The $C_2$-spectrum $Tmf_1(3)$ and its invertible modulesJul 29 2015Dec 07 2016We explore the $C_2$-equivariant spectra $Tmf_1(3)$ and $TMF_1(3)$. In particular, we compute their $C_2$-equivariant Picard groups and the $C_2$-equivariant Anderson dual of $Tmf_1(3)$. This implies corresponding results for the fixed point spectra $TMF_0(3)$ ... More
Phasor-Based Approach for Harmonic Assessment from Multiple Distributed Energy ResourcesJul 27 2014This paper analyzes impacts and interactions of harmonics from multiple sources, especially distributed energy resources, on distribution networks. We propose a new index, the Phasor Harmonic Index (PHI), that considers both harmonic source magnitude ... More
Search for transient variations of the fine structure constant and dark matter using fiber-linked optical atomic clocksJul 05 2019Jul 09 2019We search for transient variations of the fine structure constant using data from a European network of fiber-linked optical atomic clocks. By searching for coherent variations in the recorded clock frequency comparisons across the network, we significantly ... More
Orbit equivalence of graphs and isomorphism of graph groupoidsOct 31 2016Jan 24 2017We show that the groupoids of two directed graphs are isomorphic if and only if the two graphs are orbit equivalent by an orbit equivalence that preserves isolated eventually periodic points. We also give a complete description of the (topological) isolated ... More
Wireless Interference Identification with Convolutional Neural NetworksMar 02 2017The steadily growing use of license-free frequency bands requires reliable coexistence management for deterministic medium utilization. For interference mitigation, proper wireless interference identification (WII) is essential. In this work we propose ... More
$C^*$-algebras associated to Boolean dynamical systemsOct 22 2015Feb 08 2016The goal of these notes is to present the C*-algebra $C^*(B,L,\theta)$ of a Boolean dynamical system $(B,L,\theta)$, that generalizes the $C^*$-algebra associated to Labelled graphs introduced by Bates and Pask, and to determine its simplicity, its gauge ... More
Uniform trace formulae for SU(2) and SO(3) symmetry breakingJul 30 1998Nov 09 1998We develop uniform approximations for the trace formula for non-integrable systems in which SU(2) symmetry is broken by a non-linear term of the Hamiltonian. As specific examples, we investigate H\'enon-Heiles type potentials. Our formalism can also be ... More
Parameterised Complexity for AbductionJun 03 2019Abductive reasoning is a non-monotonic formalism stemming from the work of Peirce. It describes the process of deriving the most plausible explanations of known facts. Considering the positive version asking for sets of variables as explanations, we study, ... More
Stop the ChaseJan 26 2009May 06 2009The chase procedure, an algorithm proposed 25+ years ago to fix constraint violations in database instances, has been successfully applied in a variety of contexts, such as query optimization, data exchange, and data integration. Its practicability, however, ... More
Foundations of SPARQL Query OptimizationDec 19 2008Jan 26 2009The SPARQL query language is a recent W3C standard for processing RDF data, a format that has been developed to encode information in a machine-readable way. We investigate the foundations of SPARQL query optimization and (a) provide novel complexity ... More
Equivalence and stable isomorphism of groupoids, and diagonal-preserving stable isomorphisms of graph C*-algebras and Leavitt path algebrasFeb 08 2016Sep 14 2016We prove that ample groupoids with sigma-compact unit spaces are equivalent if and only if they are stably isomorphic in an appropriate sense, and relate this to Matui's notion of Kakutani equivalence. We use this result to show that diagonal-preserving ... More
$C^*$-algebras of labelled graphs III - $K$-theory computationsMar 14 2012Jan 20 2015In this paper we give a formula for the $K$-theory of the $C^*$-algebra of a weakly left-resolving labelled space. This is done by realising the $C^*$-algebra of a weakly left-resolving labelled space as the Cuntz-Pimsner algebra of a $C^*$-correspondence. ... More
Bayesian Nonparametric Analysis of Multivariate Time Series: A Matrix Gamma Process ApproachNov 26 2018While there is an increasing amount of literature about Bayesian time series analysis, only a few Bayesian nonparametric approaches to multivariate time series exist. Most methods rely on Whittle's Likelihood, involving the second order structure of a ... More
Maximal extensions and singularities in inflationary spacetimesMar 19 2018Jul 18 2018Extendibility of inflationary spacetimes with flat spatial geometry is investigated. We find that the past boundary of an inflationary spacetime becomes a so-called parallely propagated curvature singularity if the ratio $\dot{H}/a^2$ diverges at the ... More
Elementary solution to the time-independent quantum navigation problemSep 23 2014A quantum navigation problem concerns the identification of a time-optimal Hamiltonian that realises a required quantum process or task, under the influence of a prevailing `background' Hamiltonian that cannot be manipulated. When the task is to transform ... More
The integral cohomology of the group of loopsMar 01 2009Let PSigma_n denote the group that can be thought of either as the group of motions of the trivial n-component link or the group of symmetric automorphisms of a free group of rank n. The integral cohomology ring of PSigma_n is determined, establishing ... More
The BNS-invariant for the pure braid groupsJun 18 2013In 1987 Bieri, Neumann and Strebel introduced a geometric invariant for discrete groups. In this article we compute and explicitly describe the BNS-invariant for the pure braid groups.
Strong classification of purely infinite Cuntz-Krieger algebrasMay 19 2016In 2006, Restorff completed the classification of all Cuntz-Krieger algebras with finitely many ideals (i.e., those that are purely infinite) up to stable isomorphism. He left open the questions concerning strong classification up to stable isomorphism ... More
Quantum Spin Dynamics in Molecular MagnetsMay 22 2002The detailed theoretical understanding of quantum spin dynamics in various molecular magnets is an important step on the roadway to technological applications of these systems. Quantum effects in both ferromagnetic and antiferromagnetic molecular clusters ... More
A Riemannian approach to Randers geodesicsJul 29 2015Sep 01 2016In certain circumstances tools of Riemannian geometry are sufficient to address questions arising in the more general Finslerian context. We show that one such instance presents itself in the characterisation of geodesics in Randers spaces of constant ... More
High-dimensional additive modelingJun 25 2008Nov 18 2009We propose a new sparsity-smoothness penalty for high-dimensional generalized additive models. The combination of sparsity and smoothness is crucial for mathematical theory as well as performance for finite-sample data. We present a computationally efficient ... More
Black hole formation in a contracting universeSep 08 2016Sep 22 2016We study the evolution of cosmological perturbations in a contracting universe. We aim to determine under which conditions density perturbations grow to form large inhomogeneities and collapse into black holes. Our method consists in solving the cosmological ... More
Black hole formation in a contracting universeSep 08 2016Nov 15 2016We study the evolution of cosmological perturbations in a contracting universe. We aim to determine under which conditions density perturbations grow to form large inhomogeneities and collapse into black holes. Our method consists in solving the cosmological ... More
How Turbulence Enables Core-Collapse Supernova ExplosionsMay 31 2017Jan 24 2019An important result in core-collapse supernova (CCSN) theory is that spherically-symmetric, one-dimensional simulations routinely fail to explode, yet multi-dimensional simulations often explode. Numerical investigations suggest that turbulence eases ... More
Object Recognition with Multi-Scale Pyramidal Pooling NetworksJul 07 2012We present a Multi-Scale Pyramidal Pooling Network, featuring a novel pyramidal pooling layer at multiple scales and a novel encoding layer. Thanks to the former the network does not require all images of a given classification task to be of equal size. ... More
Even flying cops should think aheadJan 22 2018We study the entanglement game, which is a version of cops and robbers, on sparse graphs. While the minimum degree of a graph G is a lower bound for the number of cops needed to catch a robber in G, we show that the required number of cops can be much ... More
Optical Depth Estimates and Effective Critical Densities of Dense Gas Tracers in the Inner Parts of Nearby Galaxy DiscsDec 13 2016High critical density molecular lines like HCN(1-0) or HCO+(1-0) represent our best tool to study currently star-forming, dense molecular gas at extragalactic distances. The optical depth of these lines is a key ingredient to estimate the effective density ... More
Penetrating particle ANalyzer (PAN)Jan 14 2019Jan 21 2019PAN is a scientific instrument suitable for deep space and interplanetary missions. It can precisely measure and monitor the flux, composition, and direction of highly penetrating particles ($> \sim$100 MeV/nucleon) in deep space, over at least one full ... More
TweetCred: Real-Time Credibility Assessment of Content on TwitterMay 21 2014Jan 30 2015During sudden onset crisis events, the presence of spam, rumors and fake content on Twitter reduces the value of information contained on its messages (or "tweets"). A possible solution to this problem is to use machine learning to automatically evaluate ... More
Accuracy and performance of phase change and latent heat models in metal additive manufacturing process simulationJun 14 2019This work proposes a thermal finite element model for the simulation of metal powder bed fusion additive manufacturing processes on macroscale with a focus on phase change and latent heat effects. Specifically, two well-known existing schemes for the ... More
Reconstruction of groupoids and C*-rigidity of dynamical systemsNov 03 2017We show how to construct a graded locally compact Hausdorff \'etale groupoid from a C*-algebra carrying a coaction of a discrete group, together with a suitable abelian subalgebra. We call this groupoid the extended Weyl groupoid. When the coaction is ... More
Flow equivalence and orbit equivalence for shifts of finite type and isomorphism of their groupoidsOct 31 2016Sep 28 2018We give conditions for when continuous orbit equivalence of one-sided shift spaces implies flow equivalence of the associated two-sided shift spaces. Using groupoid techniques, we prove that this is always the case for shifts of finite type. This generalises ... More
An algorithm for list decoding number field codesJul 12 2011Apr 05 2012We present an algorithm for list decoding codewords of algebraic number field codes in polynomial time. This is the first explicit procedure for decoding number field codes whose construction were previously described by Lenstra and Guruswami. We rely ... More
Spin dynamics and coherent tunnelling in the molecular magnetic rings Fe_6 and Fe_8Sep 11 2001Apr 16 2002We present detailed calculations of low-energy spin dynamics in the ``ferric wheel'' systems Na:Fe_6 and Cs:Fe_8 in a magnetic field. We compute by exact diagonalisation the low-energy spectra and matrix elements for total-spin and N'eel-vector components, ... More
Non-CMC solutions of the Einstein constraint equations on asymptotically Euclidean manifoldsDec 02 2013In this note we prove two existence theorems for the Einstein constraint equations on asymptotically Euclidean manifolds. The first is for arbitrary mean curvature functions with restrictions on the size of the transverse-traceless data and the non-gravitational ... More
Bremsstrahlung Pair Production In Relativistic Heavy Ion CollisionJul 14 1997We calculate production of electron- and muon-pairs by the bremsstrahlung process in hadron collisions and compare it with the dominant two-photon process. Results for the total cross section are given for proton-proton and heavy-ion collisions at energies ... More
Two-dimensional imaging of the spin-orbit effective magnetic fieldDec 07 2007We report on spatially resolved measurements of the spin-orbit effective magnetic field in a GaAs/InGaAs quantum-well. Biased gate electrodes lead to an electric-field distribution in which the quantum-well electrons move according to the local orientation ... More
Fragile entanglement statisticsMay 07 2015Aug 25 2015If X and Y are independent, Y and Z are independent, and so are X and Z, one might be tempted to conclude that X, Y, and Z are independent. But it has long been known in classical probability theory that, intuitive as it may seem, this is not true in ... More
Quantum splinesJun 12 2012Sep 04 2012A quantum spline is a smooth curve parameterised by time in the space of unitary transformations, whose associated orbit on the space of pure states traverses a designated set of quantum states at designated times, such that the trace norm of the time ... More
Team Semantics for the Specification and Verification of HyperpropertiesSep 25 2017Jun 25 2018We develop team semantics for Linear Temporal Logic (LTL) to express hyperproperties, which have recently been identified as a key concept in the verification of information flow properties. Conceptually, we consider an asynchronous and a synchronous ... More
Approximation and Dependence via Multiteam SemanticsOct 30 2015Dec 21 2015We define a variant of team semantics called multiteam semantics based on multisets and study the properties of various logics in this framework. In particular, we define natural probabilistic versions of inclusion and independence atoms and certain approximation ... More
Strong Backdoors for Linear Temporal LogicFeb 16 2016In the present paper we introduce the notion of strong backdoors into the field of temporal logic for the CNF-fragment of linear temporal logic introduced by Fisher. We study the parameterised complexity of the satisfiability problem parameterised by ... More
Probabilistic team semanticsMar 06 2018Team semantics is a semantical framework for the study of dependence and independence concepts ubiquitous in many areas such as databases and statistics. In recent works team semantics has been generalised to accommodate also multisets and probabilistic ... More
Neuromorphic Hardware learns to learnMar 15 2019Mar 18 2019Hyperparameters and learning algorithms for neuromorphic hardware are usually chosen by hand. In contrast, the hyperparameters and learning algorithms of networks of neurons in the brain, which they aim to emulate, have been optimized through extensive ... More
Curious iLQR: Resolving Uncertainty in Model-based RLApr 15 2019Curiosity as a means to explore during reinforcement learning problems has recently become very popular. However, very little progress has been made in utilizing curiosity for learning control. In this work, we propose a model-based reinforcement learning ... More
Performance of the large scale HV-CMOS pixel sensor MuPix8May 22 2019The Mu3e experiment is searching for the charged lepton flavour violating decay $ \mu^+\rightarrow e^+ e^- e^+ $, aiming for an ultimate sensitivity of one in $10^{16}$ decays. In an environment of up to $10^9$ muon decays per second the detector needs ... More
Dissolution-Dynamic Nuclear Polarization with Rapid Transfer of a Polarized SolidJun 30 2018We present a new method for preparing solutions with high degrees of nuclear spin polarization. The nuclear spins in the sample are polarized using conventional dynamic nuclear polarization (DNP) at a temperature of 1.5 Kelvin and a field of 6.7 Tesla. ... More
Anomalous Hall effect in granular ferromagnetic metals and effects of weak localizationDec 16 2008Jul 27 2009We theoretically investigate the anomalous Hall effect in a system of dense-packed ferromagnetic grains in the metallic regime. Using the formalism recently developed for the conventional Hall effect in granular metals, we calculate the residual anomalous ... More
Perturb-and-MPM: Quantifying Segmentation Uncertainty in Dense Multi-Label CRFsMar 01 2017Mar 02 2017This paper proposes a novel approach for uncertainty quantification in dense Conditional Random Fields (CRFs). The presented approach, called Perturb-and-MPM, enables efficient, approximate sampling from dense multi-label CRFs via random perturbations. ... More
Polylogarithms from the bound state S-matrixJul 16 2019Higher-point functions of gauge invariant composite operators in N=4 super Yang-Mills theory can be computed via triangulation. The elementary tile in this process is the hexagon introduced for the evaluation of structure constants. A glueing procedure ... More
Co-universal algebras associated to product systems, and gauge-invariant uniqueness theoremsJun 26 2009Sep 26 2009Let X be a product system over a quasi-lattice ordered group. Under mild hypotheses, we associate to X a C*-algebra which is co-universal for injective Nica covariant Toeplitz representations of X which preserve the gauge coaction. Under appropriate amenability ... More
Cosmological perturbations and stability of nonsingular cosmologies with limiting curvatureApr 13 2017Aug 04 2017We revisit nonsingular cosmologies in which the limiting curvature hypothesis is realized. We study the cosmological perturbations of the theory and determine the general criteria for stability. For the simplest model, we find generic Ostrogradski instabilities ... More
On Quasi-Cyclic Codes as a Generalization of Cyclic CodesAug 18 2011May 25 2012In this article we see quasi-cyclic codes as block cyclic codes. We generalize some properties of cyclic codes to quasi-cyclic ones such as generator polynomials and ideals. Indeed we show a one-to-one correspondence between l-quasi-cyclic codes of length ... More
Anisotropy induced vortex lattice rearrangement in CaKFe$_4$As$_4$Feb 06 2019The magnetic penetration depth anisotropy $\gamma_\lambda=\lambda_{c}/\lambda_{ab}$ ($\lambda_{ab}$ and $\lambda_{c}$ are the in-plane and the out-of-plane components of the magnetic penetration depth) in a CaKFe$_4$As$_4$ single crystal sample (the critical ... More
Learning Neural Models for End-to-End ClusteringJul 11 2018We propose a novel end-to-end neural network architecture that, once trained, directly outputs a probabilistic clustering of a batch of input examples in one pass. It estimates a distribution over the number of clusters $k$, and for each $1 \leq k \leq ... More
Enhancing clinical MRI Perfusion maps with data-driven maps of complementary nature for lesion outcome predictionJun 12 2018Stroke is the second most common cause of death in developed countries, where rapid clinical intervention can have a major impact on a patient's life. To perform the revascularization procedure, the decision making of physicians considers its risks and ... More
Hierarchical Parallel Matrix Multiplication on Large-Scale Distributed Memory PlatformsJun 18 2013Matrix multiplication is a very important computation kernel both in its own right as a building block of many scientific applications and as a popular representative for other scientific applications. Cannon algorithm which dates back to 1969 was the ... More
On the decoding of quasi-BCH codesDec 22 2012In this paper we investigate the structure of quasi-BCH codes. In the first part of this paper we show that quasi-BCH codes can be derived from Reed-Solomon codes over square matrices extending the known relation about classical BCH and Reed-Solomon codes. ... More
Event Detection and Localization in Distribution Grids with Phasor Measurement UnitsNov 15 2016The recent introduction of synchrophasor technology into power distribution systems has given impetus to various monitoring, diagnostic, and control applications, such as system identification and event detection, which are crucial for restoring service, ... More
Topology Detection in Microgrids with Micro-SynchrophasorsJan 08 2015Network topology in distribution networks is often unknown, because most switches are not equipped with measurement devices and communication links. However, knowledge about the actual topology is critical for safe and reliable grid operation. This paper ... More
Diagnostics of a Nuclear Starburst: Water and Methanol MasersNov 19 2018We test models of starburst driven outflows using observations of the 22.2 GHz H$_2$O and 36.2 GHz class I CH$_3$OH maser lines. We have observed the starburst galaxy NGC 253 using the Karl G. Jansky Very Large Array. We present evidence for entrainment ... More
Survey of Water and Ammonia in Nearby galaxies (SWAN): Resolved Ammonia Thermometry, and Water and Methanol Masers in IC 342, NGC 6946 and NGC 2146Apr 02 2018The Survey of Water and Ammonia in Nearby galaxies (SWAN) studies atomic and molecular species across the nuclei of four star forming galaxies: NGC\,253, IC\,342, NGC\,6946, and NGC\,2146. As part of this survey, we present Karl G. Jansky Very Large Array ... More
Domain Adaptation-based Augmentation for Weakly Supervised Nuclei DetectionJul 10 2019The detection of nuclei is one of the most fundamental components of computational pathology. Current state-of-the-art methods are based on deep learning, with the prerequisite that extensive labeled datasets are available. The increasing number of patient ... More
Homocoupling defects in a conjugated polymer limit exciton diffusionDec 10 2018May 16 2019Copolymers such as PCDTBT (poly(N-9'-heptadecanyl-2,7-carbazole-alt-5,5-(4',7'-di-2-thienyl- 2',1',3'-benzothiadiazole))) are commonly employed as donor material in bulk heterojunction solar cells. Recently, chemical defects such as homocouplings have ... More
Quasi 2-D magnetism in the Kagome layer compound FeSnJul 17 2019Single crystals of the single Kagome layer compound FeSn are investigated using x-ray and neutron scattering, magnetic susceptibility and magnetization, heat capacity, resistivity, Hall, Seebeck, thermal expansion, thermal conductivity measurements and ... More
Dielectrophoretic force-driven convection in annular geometry under Earth's gravityDec 13 2018Apr 15 2019Context: A radial temperature gradient together with an inhomogeneous radial electric field gradient is applied to a dielectric fluid confined in a vertical cylindrical annulus inducing thermal electro-hydrodynamic convection. Aims: Identification of ... More
PhaseLink: A Deep Learning Approach to Seismic Phase AssociationSep 08 2018Jan 10 2019Seismic phase association is a fundamental task in seismology that pertains to linking together phase detections on different sensors that originate from a common earthquake. It is widely employed to detect earthquakes on permanent and temporary seismic ... More
Independent ferroelectric contributions and rare-earth-induced polarization reversal in multiferroic TbMn2O5Dec 08 2011Three independent contributions to the magnetically induced spontaneous polarization of multiferroic TbMn2O5 are uniquely separated by optical second harmonic generation and an analysis in terms of Landau theory. Two of them are related to the magnetic ... More
Cosmic String Loops as the Seeds of Super-Massive Black HolesMar 08 2015Jul 03 2015Recent discoveries of super-massive black holes at high redshifts indicate a possible tension with the standard Lambda CDM paradigm of early universe cosmology which has difficulties in explaining the origin of the required nonlinear compact seeds which ... More