Results for "Christian Ruben Alexander Jahren"

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Evolved Art with Transparent, Overlapping, and Geometric ShapesApr 12 2019In this work, an evolutionary art project is presented where images are approximated by transparent, overlapping and geometric shapes of different types, e.g., polygons, circles, lines. Genotypes representing features and order of the geometric shapes ... More
Evolved Art with Transparent, Overlapping, and Geometric ShapesApr 12 2019May 15 2019In this work, an evolutionary art project is presented where images are approximated by transparent, overlapping and geometric shapes of different types, e.g., polygons, circles, lines. Genotypes representing features and order of the geometric shapes ... More
Evolved Art with Transparent, Overlapping, and Geometric ShapesApr 12 2019May 16 2019In this work, an evolutionary art project is presented where images are approximated by transparent, overlapping and geometric shapes of different types, e.g., polygons, circles, lines. Genotypes representing features and order of the geometric shapes ... More
Stealth BranesJul 20 2001Jan 11 2002We discuss the brane world model of Dvali, Gabadadze and Porrati in which branes evolve in an infinite bulk and the brane curvature term is added to the action. If Z_2 symmetry between the two sides of the brane is not imposed, we show that the model ... More
D-brane couplings and Generalised GeometryJan 30 2013The goal of this paper is to re-examine D-brane Ramond-Ramond field couplings in the presence of a B-field. We will argue that the generalised geometry induced on the world volume by the B-field results in an important but subtle change on the coupling. ... More
Whitehead torsion of inertial h-cobordismsNov 13 2017We study the Whitehead torsions of inertial h-cobordisms, and identify various types representing a nested sequence of subsets of the Whitehead group. A number of examples are given to show that these subsets are all different in general.
The TensorFlow Partitioning and Scheduling Problem: It's the Critical Path!Nov 06 2017State-of-the-art data flow systems such as TensorFlow impose iterative calculations on large graphs that need to be partitioned on heterogeneous devices such as CPUs, GPUs, and TPUs. However, partitioning can not be viewed in isolation. Each device has ... More
StreamLearner: Distributed Incremental Machine Learning on Event Streams: Grand ChallengeJun 26 2017Today, massive amounts of streaming data from smart devices need to be analyzed automatically to realize the Internet of Things. The Complex Event Processing (CEP) paradigm promises low-latency pattern detection on event streams. However, CEP systems ... More
A simplification problem in manifold theoryFeb 09 2018Aug 31 2018Two smooth manifolds M and N are called R-diffeomorphic if their product with the real line are diffeomorphic. We consider the following simplification problem: does R-diffeomorphism imply diffeomorphism or homeomorphism? For compact manifolds, analysis ... More
How different can h-cobordant manifolds be?Sep 12 2012Sep 19 2012We study the homeomorphism types of manifolds h-cobordant to a fixed one. Our investigation is partly motivated by the notion of special manifolds introduced by Milnor in his study of lens spaces. In particular we revisit and clarify some of the claims ... More
Free involutions on S^1xS^nFeb 14 2008Topological free involutions on S^1xS^n are classified up to conjugation. As a byproduct we obtain a new computation of the group of concordance classes of homeomorphisms of the projective space RP^n.
Multi-layer Relation NetworksNov 05 2018Relational Networks (RN) as introduced by Santoro et al. (2017) have demonstrated strong relational reasoning capabilities with a rather shallow architecture. Its single-layer design, however, only considers pairs of information objects, making it unsuitable ... More
Universality in Chern-Simons theoryMar 04 2012May 25 2012We show that the perturbative part of the partition function in the Chern-Simons theory on a 3-sphere as well as the central charge and expectation value of the unknotted Wilson loop in the adjoint representation can be expressed in terms of the universal ... More
On duality and negative dimensions in the theory of Lie groups and symmetric spacesOct 31 2010We give one more interpretation of the symbolic formulae $U(-N)=U(N)$ and $Sp(-2N)=SO(2N)$ by comparing the values of certain Casimir operators in the corresponding tensor representations. We show also that such relations can be extended to the classical ... More
HYPE: Massive Hypergraph Partitioning with Neighborhood ExpansionOct 26 2018Nov 14 2018Many important real-world applications-such as social networks or distributed data bases-can be modeled as hypergraphs. In such a model, vertices represent entities-such as users or data records-whereas hyperedges model a group membership of the vertices-such ... More
A Link between Guruswami--Sudan's List--Decoding and Decoding of Interleaved Reed--Solomon CodesJun 08 2010The Welch--Berlekamp approach for Reed--Solomon (RS) codes forms a bridge between classical syndrome--based decoding algorithms and interpolation--based list--decoding procedures for list size l=1. It returns the univariate error--locator polynomial and ... More
A rigorous geometric derivation of the chiral anomaly in curved backgroundsAug 21 2015Apr 01 2016We discuss the chiral anomaly for a Weyl field in a curved background and show that a novel index theorem for the Lorentzian Dirac operator can be applied to describe the gravitational chiral anomaly. A formula for the total charge generated by the gravitational ... More
Fluctuations and response in a non-equilibrium micron-sized systemJun 16 2010Nov 30 2010The linear response of non-equilibrium systems with Markovian dynamics satisfies a generalized fluctuation-dissipation relation derived from time symmetry and antisymmetry properties of the fluctuations. The relation involves the sum of two correlation ... More
DeepPose: Human Pose Estimation via Deep Neural NetworksDec 17 2013Aug 20 2014We propose a method for human pose estimation based on Deep Neural Networks (DNNs). The pose estimation is formulated as a DNN-based regression problem towards body joints. We present a cascade of such DNN regressors which results in high precision pose ... More
Computation of Bivariate Characteristic Polynomials of Finitely Generated Modules over Weyl AlgebrasDec 08 2012In this paper we generalize the classical Groebner basis technique to prove the existence and present a method of computation of a dimension polynomial in two variables associated with a finitely generated D-module, that is, a finitely generated module ... More
Probing transition form factors in the rare $B\to K^*ν\barν$ decayMay 08 2018Sep 11 2018We compare the Standard Model (SM) predictions for the differential branching ratio of the rare $B\to K^*\nu\bar\nu$ decays using $B \to K^*$ form factors obtained from holographic light-front QCD (hLFQCD) and Sum Rules (SR) Distribution Amplitudes. For ... More
Generic Trace LogicsMar 16 2011We combine previous work on coalgebraic logic with the coalgebraic traces semantics of Hasuo, Jacobs, and Sokolova.
Computation of the Strength of PDEs of Mathematical Physics and their Difference ApproximationsMay 30 2012We develop a method for evaluation of A. Einstein's strength of systems of partial differential and difference equations based on the computation of Hilbert-type dimension polynomials of the associated differential and difference field extensions. Also ... More
Heteroclinic Dynamics of Localized Frequency Synchrony: Stability of Heteroclinic Cycles and NetworksOct 15 2018In the first part of this paper, we showed that three coupled populations of identical phase oscillators give rise to heteroclinic cycles between invariant sets where populations show distinct frequencies. Here, we now give explicit stability results ... More
Solving isomorphism problems about 2-designs from disjoint difference familiesJul 05 2018Recently, two new constructions of $(v,k,k-1)$ disjoint difference families in Galois rings were presented by Davis, Huczynska, and Mullen and Momihara. Both were motivated by a well-known construction of difference families from cyclotomy in finite fields ... More
Form factors in $B\to ππ\ell\barν_\ell$ from QCD light-cone sum rulesNov 08 2015Feb 29 2016The form factors of the semileptonic $B\to \pi\pi\ell\bar\nu$ decay are calculated from QCD light-cone sum rules with the distribution amplitudes of dipion states. This method is valid in the kinematical region, where the hadronic dipion state has a small ... More
An index theorem for Lorentzian manifolds with compact spacelike Cauchy boundaryJun 02 2015May 09 2018We show that the Dirac operator on a compact globally hyperbolic Lorentzian spacetime with spacelike Cauchy boundary is a Fredholm operator if appropriate boundary conditions are imposed. We prove that the index of this operator is given by the same expression ... More
Fair Division Without Disparate ImpactJun 06 2019We consider the problem of dividing items between individuals in a way that is fair both in the sense of distributional fairness and in the sense of not having disparate impact across protected classes. An important existing mechanism for distributionally ... More
An index theorem for Lorentzian manifolds with compact spacelike Cauchy boundaryJun 02 2015We show that the Dirac operator on a compact globally hyperbolic Lorentzian spacetime with spacelike Cauchy boundary is a Fredholm operator if appropriate boundary conditions are imposed. We prove that the index of this operator is given by the same expression ... More
Relays: A New Approach for the Finite Departure Problem in Overlay NetworksSep 13 2018A fundamental problem for overlay networks is to safely exclude leaving nodes, i.e., the nodes requesting to leave the overlay network are excluded from it without affecting its connectivity. To rigorously study self-tabilizing solutions to this problem, ... More
Suitable Initial Conditions for Newtonian Simulations with Massive NeutrinosOct 29 2018Initial conditions for cosmological N-body simulations are usually calculated by rescaling the present day linear power spectrum obtained from an Einstein-Boltzmann solver to the initial time employing the scale-independent matter growth function. For ... More
Semi-Bounded Restrictions of Dirac Type Operators and the Unique Continuation PropertyApr 03 2000Aug 11 2000Let M be a connected Riemannian manifold and let D be a Dirac type operator acting on smooth compactly supported sections in a Hermitian vector bundle over M. Suppose D has a self-adjoint extension A in the Hilbert space of square-integrable sections. ... More
On the Complexity of Local Graph TransformationsApr 25 2019We consider the problem of transforming a given graph $G_s$ into a desired graph $G_t$ by applying a minimum number primitives from a particular set of local graph transformation primitives. These primitives are local in the sense that each node can apply ... More
On solving isomorphism problems about 2-designs using block intersection numbersJul 11 2019In this paper, we give a partial solution to a new isomorphism problem about $2$-$(v,k,k-1)$ designs from disjoint difference families in finite fields and Galois rings. Our results are obtained by carefully calculating and bounding some block intersection ... More
Comparing AdS/QCD and Sum Rules predictions for $B\to K^*ν\barν$Jul 27 2018Using the form factors obtained from holographic AdS/QCD and QCD sum rules, we predict the differential branching ratio and longitudinal polarization fraction for the rare $B\to K^* \nu \bar\nu$ decay. This is an interesting decay channel as it does not ... More
Heating of the IGM by FRII radio sourcesFeb 01 1999We present results of a numerical integration of the hydrodynamical equations governing the self-similar, two-dimensional gas flow behind the bow shock of an FRII radio source embedded in an IGM with a power law density profile. The model predicts pressure ... More
On the cosmological evolution of the FRII radio source populationSep 22 1998Oct 21 1998We present an analytical model for the cosmological evolution of the FRII source population. Based on an earlier model for the intrinsic radio luminosity - linear size evolution of these objects, we construct theoretical source samples. The source distributions ... More
Rs-sectorial operators and generalized Triebel-Lizorkin spacesJul 17 2012We introduce a notion of generalized Triebel-Lizorkin spaces associated with sectorial operators in Banach function spaces. Our approach is based on holomorphic functional calculus techniques. Using the concept of $\mathcal{R}_s$-sectorial operators, ... More
Q-Graph: Preserving Query Locality in Multi-Query Graph ProcessingMay 30 2018Arising user-centric graph applications such as route planning and personalized social network analysis have initiated a shift of paradigms in modern graph processing systems towards multi-query analysis, i.e., processing multiple graph queries in parallel ... More
Magnetic switching dynamics in a ferrimagnetic two sub-lattice model including ultrafast exchange scatteringOct 21 2014Mar 25 2015We study the heat-induced magnetization dynamics in a toy model of a ferrimagnetic alloy, which includes localized spins antiferromagnetically coupled to an itinerant carrier system with a Stoner gap. We determine the one-particle spin-density matrix ... More
The mutual interaction of powerful radio galaxies and their environmentsSep 09 1998Using a self-similar model for the expansion of cocoons surrounding the jets in powerful extragalactic radio sources (type FRII), we investigate the influence of the properties of the gas surrounding these objects on their evolution. The variation of ... More
Generalized 4 $\times$ 4 Matrix Formalism for Light Propagation in Anisotropic Stratified Media: Study of Surface Phonon Polaritons in Polar Dielectric HeterostructuresJul 03 2017We present a generalized 4 $\times$ 4 matrix formalism for the description of light propagation in birefringent stratified media. In contrast to previous work, our algorithm is capable of treating arbitrarily anisotropic or isotropic, absorbing or non-absorbing ... More
Galactic structure in the outer disk: the field in the line of sight to the intermediate-age open cluster Tombaugh 1Dec 13 2016We employ optical photometry and high-resolution spectroscopy to study a field toward the open cluster Tombaugh 1, where we identify a complex population mixture, that we describe in terms of young and old Galactic thin disk. Of particular interest is ... More
ADWISE: Adaptive Window-based Streaming Edge Partitioning for High-Speed Graph ProcessingDec 22 2017May 30 2018In recent years, the graph partitioning problem gained importance as a mandatory preprocessing step for distributed graph processing on very large graphs. Existing graph partitioning algorithms minimize partitioning latency by assigning individual graph ... More
Fabrication, detection and operation of a three-dimensional nanomagnetic conduitJun 12 2017Three-dimensional (3D) nanomagnetic devices such as the vertical racetrack memory have attracted a huge interest due to their potential for memory and logic applications. However, their implementation has not been realised due to great challenges regarding ... More
Bursting and Synchrony in Networks of Model NeuronsOct 06 2016Bursting neurons are considered to be a potential cause of over-excitability and seizure susceptibility. The functional influence of these neurons in extended epileptic networks is still poorly understood. There is mounting evidence that the dynamics ... More
Non-minimal Higgs Inflation and Frame Dependence in CosmologyJan 23 2013We investigate a very general class of cosmological models with scalar fields non-minimally coupled to gravity. A particular representative in this class is given by the non-minimal Higgs inflation model in which the Standard Model Higgs boson and the ... More
O(α_sα) corrections to Drell-Yan processes in the resonance regionMay 27 2014Jul 14 2014Drell-Yan-like W-boson and Z-boson production in the resonance region allows for some high-precision measurements that are crucial to carry experimental tests of the Standard Model to the extremes, such as the determinations of the W-boson mass and the ... More
Weak radiative corrections to dijet production at the LHCJun 26 2013We summarize the calculation of the weak corrections to dijet production at hadron colliders, comprising tree-level effects of O(\alpha_s\alpha,\alpha^2) and loop corrections of O(\alpha_s^2\alpha). Although suppressed by the small value of the coupling ... More
Dominant $\mathcal{O}(α_sα)$ corrections to Drell-Yan processes in the resonance regionJan 08 2016Apart from the well-known NNLO QCD and NLO electroweak corrections to W- and Z-boson production at hadron colliders, the most important fixed-order corrections are given by the mixed QCD-electroweak corrections of $\mathcal{O}(\alpha_s\alpha)$. The knowledge ... More
Geometric scaling of elastic instabilities in the Taylor-Couette geometry: A theoretical, experimental and numerical studyJun 01 2018We investigate the curvature-dependence of the visco-elastic Taylor-Couette instability. The radius of curvature is changed over almost a decade and the critical Weissenberg numbers of the first linear instability are determined. Experiments are performed ... More
Hadronic effects and observables in $B\to π\ell^+\ell^-$ decay at large recoilJun 25 2015Oct 08 2015We calculate the amplitude of the rare flavour-changing neutral-current decay $B\to \pi\ell^+\ell^-$ at large recoil of the pion. The nonlocal contributions in which the weak effective operators are combined with the electromagnetic lepton-pair emission ... More
Breaking the $\tildeΩ(\sqrt{n})$ Barrier: Fast Consensus under a Late AdversaryMay 02 2018We study the consensus problem in a synchronous distributed system of $n$ nodes under an adaptive adversary that has a slightly outdated view of the system and can block all incoming and outgoing communication of a constant fraction of the nodes in each ... More
Finite Variation of Fractional Levy ProcessesDec 29 2010Various characterizations for fractional Levy process to be of finite variation are obtained, one of which is in terms of the characteristic triplet of the driving Levy process, while others are in terms of differentiability properties of the sample paths. ... More
ILP-based Local Search for Graph PartitioningFeb 20 2018Computing high-quality graph partitions is a challenging problem with numerous applications. In this paper, we present a novel meta-heuristic for the balanced graph partitioning problem. Our approach is based on integer linear programs that solve the ... More
Master Spaces for stable pairsJul 17 1996Jan 17 1997We construct master spaces for oriented torsion free sheaves coupled with morphisms into a fixed reference sheaf. These spaces are projective varieties endowed with a natural $\C^*$-action. The fixed point set of this action contains the moduli space ... More
The Topological B-model on a Mini-Supertwistor Space and Supersymmetric Bogomolny Monopole EquationsMay 18 2005Dec 09 2005In the recent paper hep-th/0502076, it was argued that the open topological B-model whose target space is a complex (2|4)-dimensional mini-supertwistor space with D3- and D1-branes added corresponds to a super Yang-Mills theory in three dimensions. Without ... More
Absolute emission rates of Spontaneous Parametric Down Conversion into single transverse Gaussian modesJan 15 2008Apr 29 2008We provide an estimate on the absolute values of the emission rate of photon pairs produced by spontaneous parametric down conversion in a bulk crystal when all interacting fields are in single transverse Gaussian modes. Both collinear and non-collinear ... More
On Underlay-Aware Self-Stabilizing Overlay NetworksSep 07 2018We present a self-stabilizing protocol for an overlay network that constructs the Minimum Spanning Tree (MST) for an underlay that is modeled by a weighted tree. The weight of an overlay edge between two nodes is the weighted length of their shortest ... More
Shared-memory Exact Minimum CutsAug 16 2018The minimum cut problem for an undirected edge-weighted graph asks us to divide its set of nodes into two blocks while minimizing the weight sum of the cut edges. In this paper, we engineer the fastest known exact algorithm for the problem. State-of-the-art ... More
Skueue: A Scalable and Sequentially Consistent Distributed QueueFeb 21 2018Aug 20 2018We propose a distributed protocol for a queue, called \textsc{Skueue}, which spreads its data fairly onto multiple processes, avoiding bottlenecks in high throughput scenarios. \textsc{Skueue} can be used in highly dynamic environments, through the addition ... More
Survey on Remote Electronic VotingFeb 09 2017Electronic and remote voting has become a large field of research and brought forth a multiplicity of schemes, systems, cryptographic primitives as well as formal definitions and requirements for electronic elections. In this survey we try to give a brief ... More
Differential cohomology and locally covariant quantum field theoryJun 05 2014Dec 08 2016We study differential cohomology on categories of globally hyperbolic Lorentzian manifolds. The Lorentzian metric allows us to define a natural transformation whose kernel generalizes Maxwell's equations and fits into a restriction of the fundamental ... More
Splitting methods for time integration of trajectories in combined electric and magnetic fieldsOct 06 2015The equations of motion of a single particle subject to an arbitrary electric and a static magnetic field form a Poisson system. We present a second-order time integration method which preserves well the Poisson structure and compare it to commonly used ... More
Data-adaptive unfolding of nonergodic spectra: Application to disordered ensemblesJan 05 2014Jan 23 2014The statistical study of spectral fluctuations can depend sensitively on the unfolding procedure that serves to separate global properties from local fluctuations. Previously, we presented a parameterfree unfolding method that we applied to standard Gaussian ... More
Graphene-Enhanced Hybrid Phase Change Materials for Thermal Management of Li-Ion BatteriesMay 17 2013Li-ion batteries are crucial components for progress in mobile communications and transport technologies. However, Li-ion batteries suffer from strong self-heating, which limits their life-time and creates reliability and environmental problems. Here ... More
Towards Establishing Monotonic Searchability in Self-Stabilizing Data Structures (full version)Dec 21 2015Distributed applications are commonly based on overlay networks interconnecting their sites so that they can exchange information. For these overlay networks to preserve their functionality, they should be able to recover from various problems like membership ... More
Asymptotically exact streaming algorithmsAug 08 2014We introduce a new computational model for data streams: asymptotically exact streaming algorithms. These algorithms have an approximation ratio that tends to one as the length of the stream goes to infinity while the memory used by the algorithm is restricted ... More
One-loop divergences for gravity non-minimally coupled to a multiplet of scalar fields: calculation in the Jordan frame. I. The main resultsJan 26 2011May 27 2011Using the generalized Schwinger-DeWitt technique, we calculate the divergent part of the one-loop effective action for gravity non-minimally coupled to a multiplet of scalar fields. All the calculations are consistently done in the Jordan frame.
The Edgeworth-Kuiper debris diskJun 11 2010(Abridged) The Edgeworth-Kuiper belt with its presumed dusty debris is a natural reference for extrsolar debris disks. We employ a new algorithm to eliminate the inclination and the distance selection effects in the known TNO populations to derive expected ... More
Dominant mixed QCD-electroweak $\mathcal{O}(α_sα)$ corrections to Drell-Yan processes in the resonance regionNov 25 2015A precise theoretical description of W- and Z-boson production in the resonance region is essential for the correct interpretation of high-precision measurements of the W-boson mass and the effective weak mixing angle. Currently, the largest unknown fixed-order ... More
Weak radiative corrections to dijet production at hadron collidersOct 01 2012We present the calculation of the most important electroweak corrections to dijet production at the LHC and the Tevatron, comprising tree-level effects of O(\alpha_s\alpha,\alpha^2) and weak loop corrections of O(\alpha_s^2\alpha). Although negligible ... More
Maximum Number of Modes of Gaussian MixturesFeb 16 2017Apr 18 2019Gaussian mixture models are widely used in Statistics. A fundamental aspect of these distributions is the study of the local maxima of the density, or modes. In particular, it is not known how many modes a mixture of $k$ Gaussians in $d$ dimensions can ... More
On a class of generating vector fields for the extremum seeking problem: Lie bracket approximation and stability propertiesMar 07 2017Nov 13 2017In this paper, we describe a broad class of control functions for extremum seeking problems. We show that it unifies and generalizes existing extremum seeking strategies which are based on Lie bracket approximations, and allows to design new controls ... More
Magnetization dynamics and damping due to electron-phonon scattering in a ferrimagnetic exchange modelMay 09 2014We present a microscopic calculation of magnetization damping for a magnetic "toy model." The magnetic system consists of itinerant carriers coupled antiferromagnetically to a dispersionless band of localized spins, and the magnetization damping is due ... More
Frontal Screens on Head-Mounted Displays to Increase Awareness of the HMD Users' State in Mixed Presence CollaborationMay 15 2019In the everyday context, e.g., a household, HMD users remain a part of the social life for Non-HMD users being co-located with them. Due to the social context situations arise that demand interaction between the HMD and the Non-HMD user. We focus on the ... More
Robust Multi-agent Counterfactual PredictionApr 03 2019We consider the problem of using logged data to make predictions about what would happen if we changed the `rules of the game' in a multi-agent system. This task is difficult because in many cases we observe actions individuals take but not their private ... More
Fork Sequential Consistency is BlockingMay 14 2008We consider an untrusted server storing shared data on behalf of clients. We show that no storage access protocol can on the one hand preserve sequential consistency and wait-freedom when the server is correct, and on the other hand always preserve fork ... More
Dynamics of end-linked star polymer structuresMay 04 2005In this work we focus on the dynamics of macromolecular networks formed by end-linking identical polymer stars. The resulting macromolecular network can then be viewed as consisting of spacers which connect branching points (the cores of the stars). We ... More
Towards a Universal Approach for Monotonic Searchability in Self-Stabilizing Overlay NetworksJul 18 2016Sep 28 2016For overlay networks, the ability to recover from a variety of problems like membership changes or faults is a key element to preserve their functionality. In recent years, various self-stabilizing overlay networks have been proposed that have the advantage ... More
Will New Horizons see dust clumps in the Edgeworth-Kuiper belt?Apr 16 2014Debris disks are thought to be sculptured by neighboring planets. The same is true for the Edgeworth-Kuiper debris disk, yet no direct observational evidence for signatures of giant planets in the Kuiper belt dust distribution has been found so far. Here ... More
Introduction to the GiNaC Framework for Symbolic Computation within the C++ Programming LanguageApr 27 2000Jul 10 2001The traditional split-up into a low level language and a high level language in the design of computer algebra systems may become obsolete with the advent of more versatile computer languages. We describe GiNaC, a special-purpose system that deliberately ... More
Mixed QCD-electroweak O(α_sα) corrections to Drell-Yan processes in the resonance region: pole approximation and non-factorizable correctionsMar 13 2014Drell-Yan-like W-boson and Z-boson production in the resonance region allows for high-precision measurements that are crucial to carry experimental tests of the Standard Model to the extremes, such as the determination of the W-boson mass and the effective ... More
RoBuSt: A Crash-Failure-Resistant Distributed Storage SystemSep 17 2014Feb 23 2015In this work we present the first distributed storage system that is provably robust against crash failures issued by an adaptive adversary, i.e., for each batch of requests the adversary can decide based on the entire system state which servers will ... More
Conformal Structures and Period Matrices of Polyhedral SurfacesSep 07 2009We recall the theory of linear discrete Riemann surfaces and show how to use it in order to interpret a surface embedded in R^3 as a discrete Riemann surface and compute its basis of holomorphic forms on it. We present numerical examples, recovering known ... More
Pressure-robustness in quasi-optimal a priori estimates for the Stokes problemJun 07 2019Recent analysis of the divergence constraint in the incompressible Stokes/Navier--Stokes problem has stressed the importance of equivalence classes of forces and how it plays a fundamental role for an accurate space discretization. Two forces in the momentum ... More
Modularization of Research Software for Collaborative Open Source DevelopmentJul 12 2019Software systems evolve over their lifetime. Changing conditions, such as requirements or customer requests make it inevitable for developers to perform adjustments to the underlying code base. Especially in the context of open source software where everybody ... More
Thermal Percolation Threshold and Thermal Properties of Composites with Graphene and Boron Nitride FillersJul 10 2018We investigated thermal properties of the epoxy-based composites with a high loading fraction - up to f=45 vol.% - of the randomly oriented electrically conductive graphene fillers and electrically insulating boron nitride fillers. It was found that both ... More
An application of Pappus' Involution Theorem in euclidean and non-euclidean geometryDec 23 2014Pappus' Involution Theorem is a powerful tool for proving theorems about non-euclidean triangles and generalized triangles in Cayley-Klein models. Its power is illustrated by proving with it some theorems about euclidean and non-euclidean polygons of ... More
Brane Content of Branes' StatesDec 16 2002Feb 16 2003The problem of decomposition of unitary irreps of (super) tensorial (i.e. extended with tensorial charges) Poincar{\'e} algebra w.r.t. its different subalgebras is considered. This requires calculation of little groups for different configurations of ... More
Membrane solitons in eight-dimensional hyper-Kaehler backgroundsNov 11 2003Dec 16 2003We derive the BPS equations satisfied by lump solitons in $(2+1)$-dimensional sigma models with toric 8-dimensional hyper-K\"ahler (${HK}_8$) target spaces and check they preserve 1/2 of the supersymmetry. We show how these solitons are realised in M ... More
On marginal deformation of WZNW model and PP-wave limit of deformed $AdS_{3}\times S^{3}$ string geometryJun 24 2002We discuss the Penrose limit of the classical string geometry obtained from a truly marginal deformation of $SL(2)\otimes SU(2)$ WZNW model.
High-energy interactions at the Pierre Auger ObservatoryOct 23 2015The interaction of Ultra High Energy Cosmic Rays (UHECRs) with the atoms of the atmosphere can occur at center-of-mass energies that surpass 100 TeV, while present human-made accelerators go up to 13 TeV. Therefore it provides a unique opportunity to ... More
On principal minors of Bezout matrixJul 06 2012Let $x_1,...,x_{n}$ be real numbers, $P(x)=p_n(x-x_1)...(x-x_n)$, and $Q(x)$ be a polynomial of degree less than or equal to $n$. Denote by $\Delta(Q)$ the matrix of generalized divided differences of $Q(x)$ with nodes $x_1,...,x_n$ and by $B(P,Q)$ the ... More
An Interpolation Procedure for List Decoding Reed--Solomon codes Based on Generalized Key EquationsOct 18 2011The key step of syndrome-based decoding of Reed-Solomon codes up to half the minimum distance is to solve the so-called Key Equation. List decoding algorithms, capable of decoding beyond half the minimum distance, are based on interpolation and factorization ... More
Demaq: A Foundation for Declarative XML Message ProcessingDec 21 2006This paper gives an overview of Demaq, an XML message processing system operating on the foundation of transactional XML message queues. We focus on the syntax and semantics of its fully declarative, rule-based application language and demonstrate our ... More
Differential cohomology and locally covariant quantum field theoryJun 05 2014We study differential cohomology on categories of globally hyperbolic Lorentzian manifolds. The Lorentzian metric allows us to define a natural transformation whose kernel generalizes Maxwell's equations and fits into a restriction of the fundamental ... More
Question of quantum equivalence between Jordan frame and Einstein frameAug 25 2014Jul 18 2015In the framework of a general scalar-tensor theory, we investigate the equivalence between two different parametrizations of fields that are commonly used in cosmology - the so-called Jordan frame and Einstein frame. While it is clear that both parametrizations ... More
Maximum Number of Modes of Gaussian MixturesFeb 16 2017Oct 30 2017Gaussian mixture models are widely used in Statistics. A fundamental aspect of these distributions is the study of the local maxima of the density, or modes. In particular, it is not known how many modes a mixture of $k$ Gaussians in $d$ dimensions can ... More
Minimum Linear Arrangement of Series-Parallel GraphsOct 16 2014We present a factor $14D^2$ approximation algorithm for the minimum linear arrangement problem on series-parallel graphs, where $D$ is the maximum degree in the graph. Given a suitable decomposition of the graph, our algorithm runs in time $O(|E|)$ and ... More