Results for "Tom Van Doorsselaere"

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Stellar flares observed in long cadence data from the Kepler missionNov 07 2017We aim to perform a statistical study of stellar flares observed by Kepler. We want to study the flare amplitude, duration, energy and occurrence rates, and how they are related to the spectral type and rotation period. To that end, we have developed ... More
Coronal loop transverse oscillations excited by different driver frequenciesMay 14 2019We analyse transverse oscillations of a coronal loop excited by continuous monoperiodic motions of the loop footpoint at different frequencies in the presence of gravity. Using the MPI-AMRVAC code, we perform three-dimensional numerical magnetohydrodynamic ... More
Broadening of the DEM by multi-shelled and turbulent loopsOct 15 2018Broad differential emission measure (DEM) distributions in the corona are a sign of multi-thermal plasma along the line-of-sight. Traditionally, this is interpreted as evidence of multi-stranded loops. Recently, however, it has been shown that multi-stranded ... More
High-frequency dynamics of active region moss as observed by IRISMay 02 2019The high temporal, spatial and spectral resolution of Interface Region Imaging Spectrograph (IRIS) has provided new insights into the understanding of different small-scale processes occurring at the chromospheric and transition region (TR) heights. We ... More
Resonant absorption of surface sausage and surface kink modes under photospheric conditionsOct 09 2017Nov 17 2017We study the effect of resonant absorption of surface sausage and surface kink modes under photospheric conditions where the slow surface sausage modes undergo resonant damping in the slow continuum and the surface kink modes in the slow and Alfv\'{e}n ... More
Wave modes excited by photospheric p-modes and mode conversion in a multi-loop systemMay 06 2019Context. Waves are ubiquitous in the solar corona and there are indications that they are excited by photospheric p-modes. However, it is unclear how p-modes in coronal loops are converted to sausage modes and transverse (kink) modes, which are observed ... More
Non-equilibrium Ionization Effects on Extreme-Ultraviolet Emissions Modulated by Standing Sausage Modes in Coronal LoopsNov 21 2018Forward-modeling the emission properties in various passbands is important for confidently identifying magnetohydrodynamic waves in the structured solar corona. We examine how Non-equilibrium Ionization (NEI) affects the Extreme Ultraviolet (EUV) emissions ... More
Observational Tests of Damping by Resonant Absorption in Coronal Loop OscillationsSep 17 2003One of the proposed damping mechanisms of coronal (transverse) loop oscillations in the kink-mode is resonant absorption as a result of the Alfven speed variation at the outer boundary of coronal loops. Analytical expressions for the period and damping ... More
Forward Modeling of SDO/AIA and X-Ray Emission from a Simulated Flux Rope EjectionApr 22 2019We conduct forward-modeling analysis based on our 2.5 dimensional magnetohydrodynamics (MHD) simulation of magnetic flux rope (MFR) formation and eruption driven by photospheric converging motion. The current sheet (CS) evolution during the MFR formation ... More
Resonant Absorption of Transverse Oscillations and Associated Heating in a Solar Prominence. I- Observational aspectsJun 30 2015Transverse magnetohydrodynamic (MHD) waves have been shown to be ubiquitous in the solar atmosphere and can in principle carry sufficient energy to generate and maintain the Sun's million-degree outer atmosphere or corona. However, direct evidence of ... More
Reflection Of Propagating Slow Magneto-acoustic Waves In Hot Coronal Loops : Multi-instrument Observations and Numerical ModellingApr 27 2016May 20 2016Slow MHD waves are important tools for understanding the coronal structures and dynamics. In this paper, we report a number of observations, from X-Ray Telescope (XRT) on board HINODE and SDO/AIA of reflecting longitudinal waves in hot coronal loops. ... More
Heating effects from driven transverse and Alfvén waves in coronal loopsNov 19 2018Recent numerical studies revealed that transverse motions of coronal loops can induce the Kelvin-Helmholtz Instability (KHI). This process could be important in coronal heating because it leads to dissipation of energy at small spatial-scale plasma interactions. ... More
Simulations of fully deformed oscillating flux tubesJan 23 2018In recent years, a number of numerical studies have been focusing on the significance of the Kelvin-Helmholtz instability (KHI) in the dynamics of oscillating coronal loops. This process enhances the transfer of energy into smaller scales, and has been ... More
Galileons from Lovelock actionsFeb 02 2011Feb 10 2011We demonstrate how, for an arbitrary number of dimensions, the Galileon actions and their covariant generalizations can be obtained through a standard Kaluza-Klein compactification of higher-dimensional Lovelock gravity. In this setup, the dilaton takes ... More
Fine strand-like structure in the solar corona from MHD transverse oscillationsMay 01 2014Current analytical and numerical modelling suggest the existence of ubiquitous thin current sheets in the corona that could explain the observed heating requirements. On the other hand, new high resolution observations of the corona indicate that its ... More
Numerical simulations of transverse oscillations in radiatively cooling coronal loopsOct 29 2015We aim to study the influence of radiative cooling on the standing kink oscillations of a coronal loop. Using the FLASH code, we solved the 3D ideal magnetohydrodynamic equations. Our model consists of a straight, density enhanced and gravitationally ... More
Heating by transverse waves in simulated coronal loopsJun 08 2017Jun 13 2017Recent numerical studies of oscillating flux tubes have established the significance of resonant absorption in the damping of propagating transverse oscillations in coronal loops. The nonlinear nature of the mechanism has been examined alongside the Kelvin-Helmholtz ... More
Wave heating in gravitationally stratified coronal loops in the presence of resistivity and viscosityJan 09 2019Jan 15 2019In recent years, coronal loops have been the focus of studies related to the damping of different magnetohydrodynamic (MHD) surface waves and their connection with coronal seismology and wave heating. For a better understanding of wave heating, we need ... More
Inverse Magnetic Catalysis in the three-flavor NJL model with axial-vector interactionNov 27 2014Dec 12 2014In this paper we explore the chiral phase transition in QCD within the three-flavor Nambu-Jona-Lasinio (NJL) model with a negative coupling constant in the isoscalar axial-vector channel, which is associated with a polarized instanton--anti-instanton ... More
An Inside Look at Sunspot Oscillations with Higher Azimuthal WavenumbersMay 17 2017Solar chromospheric observations of sunspot umbrae offer an exceptional view of magneto-hydrodynamic wave phenomena. In recent years, a wealth of wave signatures related to propagating magneto-acoustic modes have been presented, which demonstrate complex ... More
Coronal rain in magnetic arcades: Rebound shocks, Limit cycles, and Shear flowsJul 03 2015We extend our earlier multidimensional, magnetohydrodynamic simulations of coronal rain occurring in magnetic arcades with higher resolution, grid-adaptive computations covering a much longer ($>6$ hour) timespan. We quantify how in-situ forming blob-like ... More
Omnipresent long-period intensity oscillations in open coronal structuresSep 12 2012Quasi-periodic propagating disturbances in coronal structures have been interpreted as slow magneto-acoustic waves and/or periodic upflows. Here we aim to understand their nature from the observed properties using a three-hour imaging sequence from AIA/SDO ... More
Forward Modelling of Standing Kink Modes in Coronal Loops I. Synthetic ViewsMar 04 2016Kink magnetohydrodynamic (MHD) waves are frequently observed in various magnetic structures of the solar atmosphere. They may contribute significantly to coronal heating and could be used as a tool to diagnose the solar plasma. In this study, we synthesise ... More
Line-of-sight geometrical and instrumental resolution effects on intensity perturbations by sausage modesMar 25 2013Diagnostics of MHD waves in the solar atmosphere is a topic which often encounters problems of interpretation, due partly to the high complexity of the solar atmospheric medium. Forward modeling can significantly guide interpretation, bridging the gap ... More
Forward Modelling of Standing Kink Modes in Coronal Loops II. ApplicationsFeb 24 2016Magnetohydrodynamic waves are believed to play a significant role in coronal heating, and could be used for remote diagnostics of solar plasma. Both the heating and diagnostic applications rely on a correct inversion (or backward modelling) of the observables ... More
The polytropic index of solar coronal plasma in sunspot fan loops and its temperature dependenceOct 19 2018Observations of slow magneto-acoustic waves have been demonstrated to possess a number of applications in coronal seismology. Determination of the polytropic index ($\gamma$) is one such important application. Analysing the amplitudes of oscillations ... More
Generalized phase mixing: Turbulence-like behaviour from unidirectionally propagating MHD wavesFeb 08 2017Nov 02 2017We present the results of three-dimensional (3D) ideal magnetohydrodynamics (MHD) simulations on the dynamics of a perpendicularly inhomogeneous plasma disturbed by propagating Alfv\'enic waves. Simpler versions of this scenario have been extensively ... More
Simulations of Gyrosynchrotron Microwave Emission from an Oscillating 3D Magnetic LoopFeb 24 2015Radio observations of solar flares often reveal various periodic or quasi-periodic oscillations. Most likely, these oscillations are caused by magnetohydrodynamic (MHD) oscillations of flaring loops which modulate the emission. Interpretation of the observations ... More
Modelling of Reflective Propagating Slow-mode Wave in a Flaring LoopSep 15 2015Quasi-periodic propagating intensity disturbances have been observed in large coronal loops in EUV images over a decade, and are widely accepted to be slow magnetosonic waves. However, spectroscopic observations from Hinode/EIS revealed their association ... More
A Parity Game Tale of Two CountersJul 26 2018Aug 02 2018Parity games have important practical applications in formal verification and synthesis, especially for problems related to linear temporal logic and to the modal mu-calculus. The problem is believed to admit a solution in polynomial time, motivating ... More
Oink: an Implementation and Evaluation of Modern Parity Game SolversJan 11 2018Mar 05 2018Parity games have important practical applications in formal verification and synthesis, especially to solve the model-checking problem of the modal mu-calculus. They are also interesting from the theory perspective, as they are widely believed to admit ... More
The variance of the Euler totient functionJun 13 2017In this paper we study the variance of the Euler totient function (normalized to $\varphi(n)/n$) in the integers $\mathbb{Z}$ and in the polynomial ring $\mathbb{F}_q[T]$ over a finite field $\mathbb{F}_q$. It turns out that in $\mathbb{Z}$, under some ... More
Oscillations in stellar superflaresApr 07 2015Two different mechanisms may act to induce quasi-periodic pulsations (QPP) in whole-disk observations of stellar flares. One mechanism may be magneto-hydromagnetic (MHD) forces and other processes acting on flare loops as seen in the Sun. The other mechanism ... More
Computing the Cassels-Tate pairing on 3-isogeny Selmer groups via cubic norm equationsNov 07 2017We explain a method for computing the Cassels-Tate pairing on the 3-isogeny Selmer groups of an elliptic curve. This improves the upper bound on the rank of the elliptic curve coming from a descent by 3-isogeny, to that coming from a full 3-descent. One ... More
Necessary conditions for Schur-maximalityNov 27 2017May 08 2018McNamara and Pylyavskyy conjectured precisely which connected skew shapes are maximal in the Schur-positivity order, which says that $B\leq _s A$ if $s_A-s_B$ is Schur-positive. Towards this, McNamara and van Willigenburg proved that it suffices to study ... More
A large HI cloud near the centre of the Virgo clusterMay 19 2005We report the discovery of a large HI cloud in the central regions of the Virgo cluster. It is 110 x 25 kpc in size and contains 3.4 x 10^8 Msol of HI. The morphology and kinematics of this cloud strongly suggest that it consists of HI removed from the ... More
Parameterized Complexity of Graph Constraint LogicSep 09 2015Graph constraint logic is a framework introduced by Hearn and Demaine, which provides several problems that are often a convenient starting point for reductions. We study the parameterized complexity of Constraint Graph Satisfiability and both bounded ... More
An Analytical Model of the Kelvin-Helmholtz Instability of Transverse Coronal Loop OscillationsJan 18 2019Recent numerical simulations have demonstrated that transverse coronal loop oscillations are susceptible to the Kelvin-Helmholtz (KH) instability due to the counter-streaming motions at the loop boundary. We present the first analytical model of this ... More
Quasi-periodic pulsations in solar and stellar flares: an overview of recent resultsSep 09 2016Quasi-periodic pulsations (or QPPs) are periodic intensity variations in the flare emission, across all wavelength bands. In this paper, we review the observational and modelling achievements since the previous review on this topic by Nakariakov & Melnikov ... More
Observational Signatures of Waves and Flows in the Solar CoronaOct 05 2015Propagating perturbations have been observed in extended coronal loop structures for a number of years, but the interpretation in terms of slow (propagating) magneto-acoustic waves and/or as quasi-periodic upflows remains unresolved. We used forward-modelling ... More
Modelling observed decay-less oscillations as resonantly enhanced Kelvin-Helmholtz vortices from transverse MHD waves and their seismological applicationSep 30 2016In the highly structured solar corona, resonant absorption is an unavoidable mechanism of energy transfer from global transverse MHD waves to local azimuthal Alfv\'en waves. Due to its localised nature, a direct detection of this mechanism is extremely ... More
The incompleteness of complete pseudoscalar-meson photoproductionMar 12 2013May 28 2013[Background] A complete set is a minimum set of observables which allows one to determine the underlying reaction amplitudes unambiguously. Pseudoscalar-meson photoproduction from the nucleon is characterized by four such amplitudes and complete sets ... More
The Frequency-dependent Damping of Slow Magnetoacoustic Waves in a Sunspot Umbral AtmosphereAug 16 2017High spatial and temporal resolution images of a sunspot, obtained simultaneously in multiple optical and UV wavelengths, are employed to study the propagation and damping characteristics of slow magnetoacoustic waves up to transition region heights. ... More
Learning with Value-RampAug 12 2016We study a learning principle based on the intuition of forming ramps. The agent tries to follow an increasing sequence of values until the agent meets a peak of reward. The resulting Value-Ramp algorithm is natural, easy to configure, and has a robust ... More
Modules over axial algebrasApr 20 2017Jan 25 2018We introduce axial representations and modules over axial algebras as new tools to study axial algebras. All known interesting examples of axial algebras fall into this setting, in particular the Griess algebra whose automorphism group is the Monster ... More
The latest on ApertifJul 29 2010We describe a Phased Array Feed (PAF) system, called Apertif, which will be installed in the Westerbork Synthesis Radio Telescope (WSRT). The aim of Apertif is, at frequencies from 1.0 to 1.7 GHz, to increase the instantaneous field of view of the WSRT ... More
Import2vec - Learning Embeddings for Software LibrariesMar 27 2019We consider the problem of developing suitable learning representations (embeddings) for library packages that capture semantic similarity among libraries. Such representations are known to improve the performance of downstream learning tasks (e.g. classification) ... More
Local Gromov-Witten Invariants are Log InvariantsDec 14 2017Apr 28 2019We prove a simple equivalence between the virtual count of rational curves in the total space of an anti-nef line bundle and the virtual count of rational curves maximally tangent to a smooth section of the dual line bundle. We conjecture a generalization ... More
Energisation of interstellar media and cosmic ray production by jets from X-ray binariesApr 08 2005Drawing on recent estimates of the power of jets from X-ray binary systems as a function of X-ray luminosity, combined with improved estimates of the relevant Log(N)-Log(L_X) luminosity functions, we calculate the total energy input to the interstellar ... More
Revisiting Decision Diagrams for SATMay 09 2018Symbolic variants of clause distribution using decision diagrams to eliminate variables in SAT were shown to perform well on hard combinatorial instances. In this paper we revisit both existing ZDD and BDD variants of this approach. We further investigate ... More
The Role of Normware in Trustworthy and Explainable AIDec 06 2018For being potentially destructive, in practice incomprehensible and for the most unintelligible, contemporary technology is setting high challenges on our society. New conception methods are urgently required. Reorganizing ideas and discussions presented ... More
EEG-informed attended speaker extraction from recorded speech mixtures with application in neuro-steered hearing prosthesesFeb 18 2016Feb 05 2019OBJECTIVE: We aim to extract and denoise the attended speaker in a noisy, two-speaker acoustic scenario, relying on microphone array recordings from a binaural hearing aid, which are complemented with electroencephalography (EEG) recordings to infer the ... More
Tabling as a Library with Delimited ControlJul 29 2015Tabling is probably the most widely studied extension of Prolog. But despite its importance and practicality, tabling is not implemented by most Prolog systems. Existing approaches require substantial changes to the Prolog engine, which is an investment ... More
The Sierpinski Object in the Scott Realizability ToposApr 30 2019We study the Sierpinski Object in the Scott Realizability Topos.
Resonant Absorption of Transverse Oscillations and Associated Heating in a Solar Prominence. II- Numerical aspectsJun 30 2015Transverse magnetohydrodynamic (MHD) waves are ubiquitous in the solar atmosphere and may be responsible for generating the Sun's million-degree outer atmosphere. However, direct evidence of the dissipation process and heating from these waves remains ... More
Forward Modelling of Propagating Slow Waves in Coronal Loops and Their Frequency-Dependent DampingFeb 02 2016Propagating slow waves in coronal loops exhibit a damping which depends upon the frequency of the waves. In this study we aim to investigate the relationship of the damping length (L$_d$) with the frequency of the propagating wave. We present a 3-D coronal ... More
Resonant Absorption of Axisymmetric Modes in Twisted Magnetic Flux TubesJun 29 2017It has been shown recently that magnetic twist and axisymmetric MHD modes are ubiquitous in the solar atmosphere and therefore, the study of resonant absorption for these modes have become a pressing issue as it can have important consequences for heating ... More
Plasmon confinement in fractal quantum systemsJan 19 2018Recent progress in the fabrication of materials has made it possible to create arbitrary non-periodic two-dimensional structures in the quantum plasmon regime. This paves the way for exploring the plasmonic properties of electron gases in complex geometries ... More
Time delays in quasi-periodic pulsations observed during the X2.2 solar flare on 2011 February 15Mar 28 2012We report observations of quasi-periodic pulsations (QPPs) during the X2.2 flare of 2011 February 15, observed simultaneously in several wavebands. We focus on fluctuations on time scale 1-30 s and find different time lags between different wavebands. ... More
PSPACE-completeness of Bloxorz and of Games with 2-ButtonsNov 21 2014Bloxorz is an online puzzle game where players move a 1 by 1 by 2 block by tilting it on a subset of the two dimensional grid. Bloxorz features switches that open and close trapdoors. The puzzle is to move the block from its initial position to an upright ... More
Bisimilarity of Open Terms in Stream GSOSNov 08 2018Feb 12 2019Stream GSOS is a specification format for operations and calculi on infinite sequences. The notion of bisimilarity provides a canonical proof technique for equivalence of closed terms in such specifications. In this paper, we focus on open terms, which ... More
Analysis of a Gibbs sampler method for model based clustering of gene expression dataJan 14 2008Over the last decade, a large variety of clustering algorithms have been developed to detect coregulatory relationships among genes from microarray gene expression data. Model based clustering approaches have emerged as statistically well grounded methods, ... More
Drag and lift forces on a counter-rotating cylinder in rotating flowNov 24 2009Apr 06 2010Results are reported of an experimental investigation into the motion of a heavy cylinder free to move inside a water-filled drum rotating around a horizontal axis. The cylinder is observed to either co- or, counter intuitively, counter-rotate with respect ... More
Damping of nonlinear standing kink oscillations: a numerical studySep 22 2016We aim to study the standing fundamental kink mode of coronal loops in the nonlinear regime, investigating the changes in energy evolution in the cross-section and oscillation amplitude of the loop which are related to nonlinear effects, in particular ... More
The instability and non-existence of multi-stranded loops, when driven by transverse wavesApr 14 2016In recent years, omni-present transverse waves have been observed in all layers of the solar atmosphere. Coronal loops are often modeled as a collection of individual strands, in order to explain their thermal behaviour and appearance. We perform 3D ideal ... More
Automatic Detection of Online Jihadist Hate SpeechMar 13 2018We have developed a system that automatically detects online jihadist hate speech with over 80% accuracy, by using techniques from Natural Language Processing and Machine Learning. The system is trained on a corpus of 45,000 subversive Twitter messages ... More
How do neural networks see depth in single images?May 16 2019Deep neural networks have lead to a breakthrough in depth estimation from single images. Recent work often focuses on the accuracy of the depth map, where an evaluation on a publicly available test set such as the KITTI vision benchmark is often the main ... More
The Capabilities of the EISCAT Svalbard Radar for Inter-hemispheric Coordinated StudiesApr 21 2004In this article we want to present the EISCAT Svalbard Radar (ESR) in some detail, as well as some of the instruments of interest for ionospheric and magnetospheric research that are located in the vicinity of it. We particularly describe how this instrument ... More
The HI halo of NGC 2403Sep 07 2000Deep VLA HI observations of the nearby spiral galaxy NGC 2403 reveal the presence of an extended HI halo that shows slower rotation and a general inflow (about 15-25 km\s) towards the center of the galaxy.
Efficient sampling of Gaussian graphical models using conditional Bayes factorsSep 09 2014Bayesian estimation of Gaussian graphical models has proven to be challenging because the conjugate prior distribution on the Gaussian precision matrix, the G-Wishart distribution, has a doubly intractable partition function. Recent developments provide ... More
Positivity bounds on gluon TMDs for hadrons of spin $\le$ 1Sep 22 2017We consider the transverse momentum dependent gluon distribution functions (called gluon TMDs) by studying the light-front gluon-gluon correlator, extending the results for unpolarized and vector polarized targets to also include tensor polarized targets ... More
Enrichment and aggregation of topological motifs are independent organizational principles of integrated interaction networksSep 09 2011Topological network motifs represent functional relationships within and between regulatory and protein-protein interaction networks. Enriched motifs often aggregate into self-contained units forming functional modules. Theoretical models for network ... More
Quasi-periodic pulsations in a solar flare with an unusual phase shiftDec 24 2018Two kinds of processes could occur during the flare decay phase: processes of energy release or processes of energy relaxation. Quasi-periodic pulsations (QPPs) of the broadband emission are a good tool for the verification of mechanisms. We aim to study ... More
Dictionary-free MR Fingerprinting reconstruction of balanced-GRE sequencesNov 24 2017Magnetic resonance fingerprinting (MRF) can successfully recover quantitative multi-parametric maps of human tissue in a very short acquisition time. Due to their pseudo-random nature, the large spatial undersampling artifacts can be filtered out by an ... More
$A$-dependence of quasielastic charged-current neutrino-nucleus cross sectionsApr 25 2017Mar 26 2018Background: 12C has been and is still widely used in neutrino-nucleus scattering and oscillation experiments. More recently, 40Ar has emerged as an important nuclear target for current and future experiments. Liquid argon time projection chambers (LArTPCs) ... More
Circuit-Model Analysis for Spintronic Devices with Chiral Molecules as Spin InjectorsApr 05 2019Recent research discovered that charge transfer processes in chiral molecules can be spin selective and named the effect Chiral-Induced Spin Selectivity (CISS). Follow-up work studied hybrid spintronic devices with conventional electronic materials and ... More
Stable divisorial gonality is in NPAug 21 2018Divisorial gonality and stable divisorial gonality are graph parameters, which have an origin in algebraic geometry. Divisorial gonality of a connected graph $G$ can be defined with help of a chip firing game on $G$. The stable divisorial gonality of ... More
The nature of Elsässer variables in compressible MHDFeb 05 2019The Els\"{a}sser variables are often used in studies of plasma turbulence, in helping differentiate between MHD waves propagating parallel or anti-parallel to the main magnetic field. While for pure Alfv\'en waves in a homogeneous plasma the method is ... More
Neural Networks for Information RetrievalJan 07 2018Machine learning plays a role in many aspects of modern IR systems, and deep learning is applied in all of them. The fast pace of modern-day research has given rise to many approaches to many IR problems. The amount of information available can be overwhelming ... More
Gluon transverse momentum dependent correlators in polarized high energy processesSep 09 2016We investigate the gluon transverse momentum dependent correlators as Fourier transform of matrix elements of nonlocal operator combinations. At the operator level these correlators include both field strength operators and gauge links bridging the nonlocality. ... More
Improving Strong-Scaling of CNN Training by Exploiting Finer-Grained ParallelismMar 15 2019Scaling CNN training is necessary to keep up with growing datasets and reduce training time. We also see an emerging need to handle datasets with very large samples, where memory requirements for training are large. Existing training frameworks use a ... More
Influence of short-range correlations in neutrino-nucleus scatteringJun 01 2016Aug 17 2016Background: Nuclear short-range correlations (SRCs) are corrections to mean-field wave functions connected with the short-distance behavior of the nucleon-nucleon interaction. These SRCs provide corrections to lepton- nucleus cross sections as computed ... More
Causality on Longitudinal Data: Stable Specification Search in Constrained Structural Equation ModelingMay 22 2016Apr 04 2017A typical problem in causal modeling is the instability of model structure learning, i.e., small changes in finite data can result in completely different optimal models. The present work introduces a novel causal modeling algorithm for longitudinal data, ... More
Validating module network learning algorithms using simulated dataMay 04 2007In recent years, several authors have used probabilistic graphical models to learn expression modules and their regulatory programs from gene expression data. Here, we demonstrate the use of the synthetic data generator SynTReN for the purpose of testing ... More
Apertif - the focal-plane array system for the WSRTDec 01 2009We describe a focal plane array (FPA) system, called Apertif, that is being developed for the Westerbork Synthesis Radio Telescope (WSRT). The aim of Apertif is to increase the instantaneous field of view of the WSRT by a factor of 37 and its observing ... More
Gluon and Wilson loop TMDs for hadrons of spin $\leq$ 1Jul 06 2016Sep 15 2016In this paper we consider the parametrizations of gluon transverse momentum dependent (TMD) correlators in terms of TMD parton distribution functions (PDFs). These functions, referred to as TMDs, are defined as the Fourier transforms of hadronic matrix ... More
Correlations in neutrino-nucleus scatteringJun 28 2016We present a detailed study of charged-current quasielastic neutrino-nucleus scattering and of the influence of correlations on one- and two-nucleon knockout processes. The quasielastic neutrino-nucleus scattering cross sections, including the influence ... More
Prospects of Transition Interface Sampling simulations for the theoretical study of zeolite synthesisJan 15 2007The transition interface sampling (TIS) technique allows to overcome large free energy barriers within reasonable simulation time, which is impossible for straightforward molecular dynamics. Still, the method does not impose an artificial driving force, ... More
On Exploration, Exploitation and Learning in Adaptive Importance SamplingOct 31 2018We study adaptive importance sampling (AIS) as an online learning problem and argue for the importance of the trade-off between exploration and exploitation in this adaptation. Borrowing ideas from the bandits literature, we propose Daisee, a partition-based ... More
Comparative analysis of module-based versus direct methods for reverse-engineering transcriptional regulatory networksMay 07 2009We have compared a recently developed module-based algorithm LeMoNe for reverse-engineering transcriptional regulatory networks to a mutual information based direct algorithm CLR, using benchmark expression data and databases of known transcriptional ... More
Synthesis of Biologically Realistic Human Motion Using Joint Torque ActuationApr 30 2019Using joint actuators to drive the skeletal movements is a common practice in character animation, but the resultant torque patterns are often unnatural or infeasible for real humans to achieve. On the other hand, physiologically-based models explicitly ... More
Herding Vulnerable Cats: A Statistical Approach to Disentangle Joint Responsibility for Web Security in Shared HostingAug 22 2017Hosting providers play a key role in fighting web compromise, but their ability to prevent abuse is constrained by the security practices of their own customers. {\em Shared} hosting, offers a unique perspective since customers operate under restricted ... More
Dueling Network Architectures for Deep Reinforcement LearningNov 20 2015Apr 05 2016In recent years there have been many successes of using deep representations in reinforcement learning. Still, many of these applications use conventional architectures, such as convolutional networks, LSTMs, or auto-encoders. In this paper, we present ... More
Decomposition algebras and axial algebrasMay 09 2019We introduce decomposition algebras as a natural generalization of axial algebras, Majorana algebras and the Griess algebra. They remedy three limitations of axial algebras: (1) They separate fusion laws from specific values in a field, thereby allowing ... More
Regularizing Solutions to the MEG Inverse Problem Using Space-Time Separable Covariance FunctionsApr 17 2016In magnetoencephalography (MEG) the conventional approach to source reconstruction is to solve the underdetermined inverse problem independently over time and space. Here we present how the conventional approach can be extended by regularizing the solution ... More
A recursive estimation approach to distributed identification of large-scale multi-input-single-output FIR systemsJul 21 2018The problem of identifying single modules in multiple-input-single-output (MISO) systems is considered. A novel approach to distributed identification of MISO finite impulse response systems is presented. The distributed identification is discerned by ... More
Pulsating or not? A search for hidden pulsations below the red edge of the ZZ instability stripJun 05 2002The location of the red edge of the ZZ Ceti instability strip is defined observationally as being the lowest temperature for which a white dwarf with a H-rich atmosphere (DA) is known to exhibit periodic brightness variations. Whether this cut-off in ... More
Putting Logic-Based Distributed Systems on Stable GroundsJul 20 2015Jul 25 2015In the Declarative Networking paradigm, Datalog-like languages are used to express distributed computations. Whereas recently formal operational semantics for these languages have been developed, a corresponding declarative semantics has been lacking ... More
Tranco: A Research-Oriented Top Sites Ranking Hardened Against ManipulationJun 04 2018Dec 17 2018In order to evaluate the prevalence of security and privacy practices on a representative sample of the Web, researchers rely on website popularity rankings such as the Alexa list. While the validity and representativeness of these rankings are rarely ... More
Reverse-engineering transcriptional modules from gene expression dataApr 08 2009"Module networks" are a framework to learn gene regulatory networks from expression data using a probabilistic model in which coregulated genes share the same parameters and conditional distributions. We present a method to infer ensembles of such networks ... More