Results for "Risto Paatelainen"

total 141took 0.12s
Minijet initial state of heavy-ion collisions from next-to-leading order perturbative QCDSep 11 2014The aim of this thesis is to calculate field-theoretically as rigorously as possible the initial state of partonic matter produced in ultrarelativistic heavy-ion collisions at CERN-LHC and BNL-RHIC colliders. The computed minijet initial conditions are ... More
The one loop gluon emission light cone wave functionNov 02 2016Light cone perturbation theory has become an essential tool to calculate cross sections for various small-$x$ dilute-dense processes such as deep inelastic scattering and forward proton-proton and proton-nucleus collisions. Here we set out to do one loop ... More
The one loop gluon emission light cone wave functionNov 02 2016Feb 21 2017Light cone perturbation theory has become an essential tool to calculate cross sections for various small-$x$ dilute-dense processes such as deep inelastic scattering and forward proton-proton and proton-nucleus collisions. Here we set out to do one loop ... More
Gluon Radiation from a Classical Point ParticleMar 04 2019We consider an initially at rest colored particle which is struck by an ultra-relativistic nucleus. The particle is treated classically both with respect to its motion and its color charge. The nucleus is treated as a sheet of colored glass within the ... More
Latest results from the EbyE NLO EKRT modelApr 13 2017We review the results from the event-by-event next-to-leading order perturbative QCD + saturation + viscous hydrodynamics (EbyE NLO EKRT) model. With a simultaneous analysis of LHC and RHIC bulk observables we systematically constrain the QCD matter shear ... More
Systematics of the charged-hadron P_T spectrum and the nuclear suppression factor in heavy-ion collisions from sqrt{s}=200 GeV to sqrt{s} =2.76 TeVMar 28 2011Jun 01 2011In this paper, our goal is to make a simultaneous analysis of the high- and low-P_T parts of the charged-hadron P_T spectrum measured by the ALICE collaboration in central Pb-Pb collisions at sqrt{s}=2.76 TeV at the Large Hadron Collider (LHC), based ... More
Latest predictions from the EbyE NLO EKRT modelJul 06 2018We present the latest results from the NLO pQCD + saturation + viscous hydrodynamics (EbyE NLO EKRT) model. The parameters in the EKRT saturation model are fixed by the charged hadron multiplicity in the 0-5 \% 2.76 TeV Pb+Pb collisions. The $\sqrt{s}$, ... More
Turning the LHC Ring into a New Physics Search MachineFeb 28 2017The LHC Collider Ring is proposed to be turned into an ultimate automatic search engine for new physics in four consecutive phases: (1) Searches for heavy particles produced in Central Exclusive Process (CEP): pp -> p + X + p based on the existing Beam ... More
A Preon Model Based UniverseOct 31 2002Dec 31 2004The model is not satisfactory.
Transversality of isotropic projections, unrectifiability and Heisenberg groupsMay 14 2012We show that the family of $m$-dimensional isotropic projections in $\R^{2n}$ is transversal. As an application we show that the Besicovitch-Federer projection theorem holds for isotropic projections. We also use transversality to obtain almost sure estimates ... More
Extracting $\hat{q}$ in event-by-event hydrodynamics and the centrality/energy puzzleMay 03 2017In our analysis, we combine event-by-event hydrodynamics, within the EKRT formulation, with jet quenching -ASW Quenching Weights- to obtain high-$p_T$ $R_{\rm AA}$ for charged particles at RHIC and LHC energies for different centralities. By defining ... More
Difference Picard theorem for meromorphic functions of several variablesMar 23 2009It is shown that if three distinct values of a meromorphic function f:C^n -> P^1 of hyper-order strictly less than 2/3 have forward invariant pre-images with respect to a translation t:C^n -> C^n, t(z)=z+c, then f is a periodic function with period c. ... More
Supersymmetric Preons and the Standard ModelApr 30 2018The experimental fact that standard model superpartners have not been observed compels one to consider an alternative implementation for supersymmetry. The basic supermultiplet proposed here consists of a photon and a charged spin 1/2 preon field, and ... More
Soft Decision Decoding of the Orthogonal Complex MIMO Codes for Three and Four Transmit AntennasJan 11 2010Orthogonality is a much desired property for MIMO coding. It enables symbol-wise decoding, where the errors in other symbol estimates do not affect the result, thus providing an optimality that is worth pursuing. Another beneficial property is a low complexity ... More
Sharp forms of Nevanlinna error terms in differential equationsAug 21 2006Sharp versions of some classical results in differential equations are given. Main results consists of a Clunie and a Mohon'ko type theorems, both with sharp forms of error terms. The sharpness of these results is discussed and some applications to nonlinear ... More
Creative AI Through Evolutionary ComputationJan 12 2019In the last decade or so we have seen tremendous progress in Artificial Intelligence (AI). AI is now in the real world, powering applications that have a large practical impact. Most of it is based on modeling, i.e. machine learning of statistical models ... More
A new Clunie type theorem for difference polynomialsMar 25 2009It is shown that if w(z) is a finite-order meromorphic solution of the equation H(z,w) P(z,w) = Q(z,w), where P(z,w) = P(z,w(z),w(z+c_1),...,w(z+c_n)) is a homogeneous difference polynomial with meromorphic coefficients, and H(z,w) = H(z,w(z)) and Q(z,w) ... More
Systematics of parton-medium interaction from RHIC to LHCJun 13 2011Despite a wealth of experimental data for high-P_T processes in heavy-ion collisions, discriminating between different models of hard parton-medium interactions has been difficult. A key reason is that the pQCD parton spectrum at RHIC is falling so steeply ... More
An extension of Picard's theorem for meromorphic functions of small hyper-orderMar 23 2009Apr 16 2009A version of the second main theorem of Nevanlinna theory is proved, where the ramification term is replaced by a term depending on a certain composition operator of a meromorphic function of small hyper-order. As a corollary of this result it is shown ... More
Constraining energy loss from high-$p_{\rm T}$ azimuthal asymmetriesFeb 20 2019The nuclear modification factor $R_{\rm AA}$ has been satisfactorily described by various jet quenching models. Nonetheless, all these formalisms, until very recently, underpredicted the high-$p_{\rm T}$ (> 10 GeV) elliptic flow $v_2$. We find that the ... More
Temperature dependence of $η/s$: uncertainties from the equation of stateNov 05 2018We perform a global model-to-data comparison on Au+Au collisions at $\sqrt{s_{NN}}=200$ GeV and Pb+Pb collisions at $2.76$ TeV and $5.02$ TeV, using a 2+1D hydrodynamics model with the EKRT initial state and a shear viscosity over entropy density ratio ... More
Jet quenching as a probe of the initial stages in heavy-ion collisionsFeb 08 2019Jet quenching provides a very flexible variety of observables which are sensitive to different energy- and time-scales of the strongly interacting matter created in heavy-ion collisions. Exploiting this versatility would make jet quenching an excellent ... More
Event-by-event fluctuations in perturbative QCD + saturation + hydro model: pinning down QCD matter shear viscosity in ultrarelativistic heavy-ion collisionsMay 11 2015We introduce an event-by-event perturbative-QCD + saturation + hydro ("EKRT") framework for ultrarelativistic heavy-ion collisions, where we compute the produced fluctuating QCD-matter energy densities from next-to-leading order perturbative QCD using ... More
Pinning down QCD-matter shear viscosity in ultrarelativistic heavy-ion collisions via EbyE fluctuations using pQCD + saturation + hydrodynamicsSep 09 2015We introduce an event-by-event pQCD + saturation + hydro ("EKRT") framework for high-energy heavy-ion collisions, where we compute the produced fluctuating QCD-matter energy densities from next-to-leading order (NLO) perturbative QCD (pQCD) using saturation ... More
Comment on "Motion of a helical vortex filament in superfluid 4He under the extrinsic form of the local induction approximation"Oct 01 2013We comment on the paper by Van Gorder ["Motion of a helical vortex filament in superfluid ${}^4$He under the extrinsic form of the local induction approximation", Phys. Fluids 25, 085101 (2013)]. We point out that the flow of the normal fluid component ... More
Beyond Shared Hierarchies: Deep Multitask Learning through Soft Layer OrderingOct 31 2017Feb 13 2018Existing deep multitask learning (MTL) approaches align layers shared between tasks in a parallel ordering. Such an organization significantly constricts the types of shared structure that can be learned. The necessity of parallel ordering for deep MTL ... More
Existence of meromorphic solutions of first order difference equationsAug 25 2017May 30 2018It is shown that if It is shown that if \begin{equation}\label{abstract_eq} f(z+1)^n=R(z,f),\tag{\dag} \end{equation} where $R(z,f)$ is rational in $f$ with meromorphic coefficients and $\deg_f(R(z,f))=n$, has an admissible meromorphic solution, then ... More
Value distribution and linear operatorsSep 12 2013Nevanlinna's second main theorem is a far-reaching generalisation of Picard's Theorem concerning the value distribution of an arbitrary meromorphic function f. The theorem takes the form of an inequality containing a ramification term in which the zeros ... More
Improved Training Speed, Accuracy, and Data Utilization Through Loss Function OptimizationMay 27 2019As the complexity of neural network models has grown, it has become increasingly important to optimize their design automatically through metalearning. Methods for discovering hyperparameters, topologies, and learning rate schedules have lead to significant ... More
Second Main Theorem in the Tropical Projective SpaceJan 22 2014Feb 27 2015Tropical Nevanlinna theory, introduced by Halburd and Southall as a tool to analyze integrability of ultra-discrete equations, studies the growth and complexity of continuous piecewise linear real functions. The purpose of this paper is to extend tropical ... More
Optimal Sensing via Multi-armed Bandit Relaxations in Mixed Observability DomainsMar 15 2016Sequential decision making under uncertainty is studied in a mixed observability domain. The goal is to maximize the amount of information obtained on a partially observable stochastic process under constraints imposed by a fully observable internal state. ... More
From Nodes to Networks: Evolving Recurrent Neural NetworksMar 12 2018Jun 07 2018Gated recurrent networks such as those composed of Long Short-Term Memory (LSTM) nodes have recently been used to improve state of the art in many sequential processing tasks such as speech recognition and machine translation. However, the basic structure ... More
Pseudo-task Augmentation: From Deep Multitask Learning to Intratask Sharing---and BackMar 11 2018Jun 12 2018Deep multitask learning boosts performance by sharing learned structure across related tasks. This paper adapts ideas from deep multitask learning to the setting where only a single task is available. The method is formalized as pseudo-task augmentation, ... More
Planning for robotic exploration based on forward simulationFeb 09 2015Jun 29 2016We address the problem of controlling a mobile robot to explore a partially known environment. The robot's objective is the maximization of the amount of information collected about the environment. We formulate the problem as a partially observable Markov ... More
Antecedents for Successful Collaboration in Requirements EngineeringJun 05 2016The main focus of the requirements engineering (RE) literature has been on the technical aspects related to the RE projects. Furthermore, research has mainly focused on the specific methods for collecting the requirements for an information system. To ... More
Value distribution theory of $q$-differences in several complex variablesDec 22 2016Feb 23 2017In this paper, $q$-difference analogues of several central results in value distribution theory of several complex variables are obtained. The main result is the $q$-difference second main theorem for hypersurfaces. In addition, $q$-difference versions ... More
Observables of QCD DiffractionDec 03 2016A new combinatorial vector space measurement model is introduced for soft QCD diffraction. The model independent mathematical construction resolves experimental complications; the theoretical framework of the approach includes the Good-Walker view of ... More
Modular Universal Reparameterization: Deep Multi-task Learning Across Diverse DomainsMay 31 2019As deep learning applications continue to become more diverse, an interesting question arises: Can general problem solving arise from jointly learning several such diverse tasks? To approach this question, deep multi-task learning is extended in this ... More
Studies of Differences from the point of view of Nevanlinna TheoryJun 01 2018This paper consists of three parts. First, we give so far the best condition under which the shift invariance of the counting function, and of the characteristic of a subharmonic function, holds. Second, a difference analogue of logarithmic derivative ... More
Observables of QCD DiffractionDec 03 2016Dec 13 2016A new combinatorial vector space measurement model is introduced for soft QCD diffraction. The model independent mathematical construction resolves experimental complications; the theoretical framework of the approach includes the Good-Walker view of ... More
Meromorphic solutions of algebraic difference equationsJan 05 2017May 11 2017It is shown that the difference equation \begin{equation}\label{abseq} (\Delta f(z))^2=A(z)(f(z)f(z+1)-B(z)), \qquad\qquad (1) \end{equation} where $A(z)$ and $B(z)$ are meromorphic functions, possesses a continuous limit to the differential equation ... More
A new version of the second main theorem for meromorphic mappings intersecting hyperplanes in several complex variablesJan 21 2016Let $c\in \mathbb{C}^{m},$ $f:\mathbb{C}^{m}\rightarrow\mathbb{P}^{n}(\mathbb{C})$ be a linearly nondegenerate meromorphic mapping over the field $\mathcal{P}_{c}$ of $c$-periodic meromorphic functions in $\mathbb{C}^{m}$, and let $H_{j}$ $(1\leq j\leq ... More
Enhancing Evolutionary Conversion Rate Optimization via Multi-armed Bandit AlgorithmsMar 10 2018Nov 16 2018Conversion rate optimization means designing web interfaces such that more visitors perform a desired action (such as register or purchase) on the site. One promising approach, implemented in Sentient Ascend, is to optimize the design using evolutionary ... More
Growth of meromorphic solutions of delay differential equationsFeb 26 2016Necessary conditions are obtained for certain types of rational delay differential equations to admit a non-rational meromorphic solution of hyper-order less than one. The equations obtained include delay Painlev\'e equations and equations solved by elliptic ... More
From minijet saturation to global observables in A + A collisions at the LHC and RHICApr 30 2014We review the recent results from the computation of saturated next-to-leading order perturbative QCD minijet intial conditions combined with viscous hydrodynamical evolution of ultrarelativistic heavy-ion collisions at the LHC and RHIC. Comparison with ... More
Fluid dynamics with saturated minijet initial conditions in ultrarelativistic heavy-ion collisionsOct 11 2013Using next-to-leading order perturbative QCD and a conjecture of saturation to suppress the production of low-energy partons, we calculate the initial energy densities and formation times for the dissipative fluid dynamical evolution of the quark-gluon ... More
Central Diffraction at the LHCbJul 22 2009Jul 23 2009The LHCb experiment is shown to be ideal for studies of exclusive final states from central diffractive reactions. The gluon-rich environment of the central system allows detailed QCD studies and searches for exotic meson states, such as glueballs, molecules, ... More
Central Diffraction at ALICESep 17 2010The ALICE experiment is shown to be well suited for studies of exclusive final states from central diffractive reactions. The gluon-rich environment of the central system allows detailed QCD studies and searches for exotic meson states, such as glueballs, ... More
Multiplicities and $p_T$ spectra in ultrarelativistic heavy ion collisions from a next-to-leading order improved perturbative QCD + saturation + hydrodynamics modelNov 02 2012We bring the EKRT framework, which combines perturbative QCD (pQCD) minijet production with gluon saturation and hydrodynamics, to next-to-leading order (NLO) in pQCD as rigorously as possible. We chart the model uncertainties, and study the viability ... More
Vortex filament method as a tool for computational visualization of quantum turbulenceMay 13 2013Feb 20 2014Vortex filament model has become a standard and powerful tool to visualize the motion of quantized vortices in helium superfluids. In this article, we present an overview of the method and highlight its impact in aiding our understanding of quantum turbulence, ... More
Polymer adhesion: first-principles calculations of the adsorption of organic molecules onto Si surfacesApr 16 2007The structures and energetics of organic molecules adsorbed onto clean and H-passivated Si(001)-(2$\times$1) surfaces have been calculated using density functional theory. For benzene adsorbed on the clean Si surface the tight-bridge structure was found ... More
Predictions for 5.023 TeV Pb+Pb collisions at the LHCNov 13 2015We compute predictions for various low-transverse-momentum bulk observables in $\sqrt{s_{NN}} = 5.023$ TeV Pb+Pb collisions at the LHC from the event-by-event next-to-leading-order perturbative-QCD + saturation + viscous hydrodynamics ("EKRT") model. ... More
Pinning down QCD-matter shear viscosity in A+A collisions via EbyE fluctuations using pQCD + saturation + hydrodynamicsDec 16 2015We compute the initial energy densities produced in ultrarelativistic heavy-ion collisions from NLO perturbative QCD using a saturation conjecture to control soft particle production, and describe the subsequent space-time evolution of the system with ... More
Holomorphic curves with shift-invariant hyperplane preimagesMar 18 2009Sep 13 2012If f: C -> P^n is a holomorphic curve of hyper-order less than one for which 2n + 1 hyperplanes in general position have forward invariant preimages with respect to the translation t(z)=z+c, then f is periodic with period c. This result, which can be ... More
Power Allocation for Type-I ARQ Two-Hop Cooperative Networks for Ultra-Reliable CommunicationApr 14 2019We analyze the performance of amplify-and-forward (AF) automatic repeat request (ARQ) for a two-hop cooperative system with reliability constrains. For this setup, we first derive the closed-form outage probability expression. Next, we present a power ... More
Quantum turbulence in superfluids with wall-clamped normal componentNov 13 2013In Fermi superfluids, like superfluid 3He, the viscous normal component can be considered to be stationary with respect to the container. The normal component interacts with the superfluid component via mutual friction which damps the motion of quantized ... More
Evidence against the polarization rotation model of piezoelectric perovskites at the morphotropic phase boundaryOct 15 2008The origin of the very large piezoelectric response observed in the vicinity of the morphotropic phase boundary (MPB) in perovskite lead zirconate titanate and related systems has been under intensive studies. Polarization rotation ideas are frequently ... More
On the amplification of diffusion on piecewise linear potentails by direct currentAug 27 2002Oct 01 2002The diffusive motion of overdamped Brownian particles in tilted piecewise linear pontentials is considered. It is shown that the enhancement of diffusion coefficient by an external static force is quite sensitive to the symmetry of periodic potential. ... More
Three and four current reversals versus temperature in correlation ratchets with a simple sawtooh potentialJul 01 2002Oct 01 2002Transport of Brownian particles on a simple sawtooth potential subjected to both unbiased thermal and nonequilibrium symmetric three-level Markovian noise is considered. The new effects of three and four current reversals as a function of temperature ... More
Looking for pure glueball statesMar 15 2018Feb 07 2019A phenomenological analysis of the scalar glueball and scalar meson spectra is carried out by using the $AdS/QCD$ framework in the bottom-up approach. We make use of the relation between the mode functions in $AdS/QCD$ and the wave functions in Light-Front ... More
Higher Rank Interference Effect on Weak Beamforming or OSTBC TerminalsApr 05 2014Oct 15 2014User performance on a wireless network depends on whether a neighboring cochannel interferer applies a single (spatial) stream or a multi stream transmission. This work analyzes the impact of interference rank on a beamforming and orthogonal space-time ... More
On the Transition from Potential Flow to Turbulence Around a Microsphere Oscillating in Superfluid ^4HeJan 20 2017Nov 16 2017The flow of superfluid $^4$He around a translationally oscillating sphere, levitating without mechanical support, can either be laminar or turbulent, depending on the velocity amplitude. Below a critical velocity $v_c$ that scales as $\omega ^{1/2}$, ... More
Next-to-leading order improved perturbative QCD + saturation + hydrodynamics model for A+A collisionsJan 21 2014We calculate initial conditions for the hydrodynamical evolution in ultrarelativistic heavy-ion collisions at the LHC and RHIC in an improved next-to-leading order perturbative QCD + saturation framework. Using viscous relativistic hydrodynamics, we show ... More
Quantifying Point-Prediction Uncertainty in Neural Networks via Residual Estimation with an I/O KernelJun 03 2019Neural Networks (NNs) have been extensively used for a wide spectrum of real-world regression tasks, where the goal is to predict a numerical outcome such as revenue, effectiveness, or a quantitative result. In many such tasks, the point prediction is ... More
Looking for pure glueball statesMar 15 2018Aug 07 2019A phenomenological analysis of the scalar glueball and scalar meson spectra is carried out by using the $AdS/QCD$ framework in the bottom-up approach. We make use of the relation between the mode functions in $AdS/QCD$ and the wave functions in Light-Front ... More
Difference analogue of Cartan's Second Main Theorem for slowly moving periodic targetsMar 02 2016We extend the difference analogue of Cartan's second main theorem for the case of slowly moving periodic hyperplanes, and introduce two different natural ways to find a difference analogue of the truncated second main theorem. As applications, we obtain ... More
Evolutionary Architecture Search For Deep Multitask NetworksMar 10 2018Apr 17 2018Multitask learning, i.e. learning several tasks at once with the same neural network, can improve performance in each of the tasks. Designing deep neural network architectures for multitask learning is a challenge: There are many ways to tie the tasks ... More
Hierarchical Policy Design for Sample-Efficient Learning of Robot Table Tennis Through Self-PlayNov 30 2018Feb 17 2019Training robots with physical bodies requires developing new methods and action representations that allow the learning agents to explore the space of policies efficiently. This work studies sample-efficient learning of complex policies in the context ... More
Functional Generative Design: An Evolutionary Approach to 3D-PrintingApr 19 2018Consumer-grade printers are widely available, but their ability to print complex objects is limited. Therefore, new designs need to be discovered that serve the same function, but are printable. A representative such problem is to produce a working, reliable ... More
Low-Mass Diffraction at the LHCJun 16 2011Jul 06 2011The expected resonance structure for the low-mass single diffractive states from a Regge-dual model elaborated paper by the present authors in a previous is predicted. Estimates for the observable low-mass single diffraction dissociation (SDD) cross sections ... More
An information model for modular robots: the Hardware Robot Information Model (HRIM)Feb 05 2018Feb 16 2018Today's landscape of robotics is dominated by vertical integration where single vendors develop the final product leading to slow progress, expensive products and customer lock-in. Opposite to this, an horizontal integration would result in a rapid development ... More
Toward Multimodal Model-Agnostic Meta-LearningDec 18 2018Gradient-based meta-learners such as MAML are able to learn a meta-prior from similar tasks to adapt to novel tasks from the same distribution with few gradient updates. One important limitation of such frameworks is that they seek a common initialization ... More
Superconducting receiver arrays for magnetic resonance imagingMay 22 2018Superconducting QUantum-Interference Devices (SQUIDs) make magnetic resonance imaging (MRI) possible in ultra-low microtesla-range magnetic fields. In this work, we investigate the design parameters affecting the signal and noise performance of SQUID-based ... More
Computational study of (111) epitaxially strained ferroelectric perovskites BaTiO3 and PbTiO3Jun 03 2008Aug 18 2008The phase transition behaviour of PbTiO3 and BaTiO3 under (111) epitaxial strain is investigated using density-functional theory calculations. From tensile strains of +0.015 to compressive strains of -0.015, PbTiO3 undergoes phase transitions from C2 ... More
Increasing Behavioral Complexity for Evolved Virtual Creatures with the ESP MethodOct 27 2015Since their introduction in 1994 (Sims), evolved virtual creatures (EVCs) have employed the coevolution of morphology and control to produce high-impact work in multiple fields, including graphics, evolutionary computation, robotics, and artificial life. ... More
Clauser-Horne-Shimony-Holt Bell inequality test in an optomechanical deviceMar 01 2018Oct 17 2018We propose here a scheme, based on the measurement of quadrature phase coherence, aimed at testing the Clauser-Horne-Shimony-Holt Bell inequality in an optomechanical setting. Our setup is constituted by two optical cavities dispersively coupled to a ... More
A Comparison of the Taguchi Method and Evolutionary Optimization in Multivariate TestingAug 25 2018Multivariate testing has recently emerged as a promising technique in web interface design. In contrast to the standard A/B testing, multivariate approach aims at evaluating a large number of values in a few key variables systematically. The Taguchi method ... More
Meta Continual LearningJun 11 2018Using neural networks in practical settings would benefit from the ability of the networks to learn new tasks throughout their lifetimes without forgetting the previous tasks. This ability is limited in the current deep neural networks by a problem called ... More
Singularity of projections of 2-dimensional measures invariant under the geodesic flowApr 14 2011We show that on any compact Riemann surface with variable negative curvature there exists a measure which is invariant and ergodic under the geodesic flow and whose projection to the base manifold is 2-dimensional and singular with respect to the 2-dimensional ... More
Automatic Spatial Calibration of Ultra-Low-Field MRI for High-Accuracy Hybrid MEG--MRIMar 15 2019With a hybrid MEG--MRI device that uses the same sensors for both modalities, the co-registration of MRI and MEG data can be replaced by an automatic calibration step. Based on the highly accurate signal model of ultra-low-field (ULF) MRI, we introduce ... More
Non-Equilibrium Electron Transport in Two-Dimensional Nano-Structures Modeled by Green's Functions and the Finite-Element MethodAug 06 2003We use the effective-mass approximation and the density-functional theory with the local-density approximation for modeling two-dimensional nano-structures connected phase-coherently to two infinite leads. Using the non-equilibrium Green's function method ... More
Influence of van der Waals forces on the adsorption structure of benzene on siliconMar 19 2008May 14 2008Two different adsorption configurations of benzene on the Si(001)-(2x1) surface, the tight-bridge and butterfly structures, were studied using density functional theory. Several exchange and correlation functionals were used, including the recently developed ... More
Mason's theorem with a difference radicalJun 01 2018Differential calculus is not a unique way to observe polynomial equations such as $a+b=c$. We propose a way of applying difference calculus to estimate multiplicities of the roots of the polynomials $a$, $b$ and $c$ satisfying the equation above. Then ... More
Evaluation of Deep Reinforcement Learning Methods for Modular RobotsFeb 07 2018We propose a novel framework for Deep Reinforcement Learning (DRL) in modular robotics using traditional robotic tools that extend state-of-the-art DRL implementations and provide an end-to-end approach which trains a robot directly from joint states. ... More
Hierarchical Learning for Modular RobotsFeb 12 2018We argue that hierarchical methods can become the key for modular robots achieving reconfigurability. We present a hierarchical approach for modular robots that allows a robot to simultaneously learn multiple tasks. Our evaluation results present an environment ... More
Non-linear spin torque, pumping and cooling in superconductor/ferromagnet systemsJun 30 2019We study the effects of the coupling between magnetization dynamics and the electronic degrees of freedom in a heterostructure of a metallic nanomagnet with dynamic magnetization coupled with a superconductor containing a steady spin-splitting field. ... More
Constrained Phase Noise Estimation in OFDM Using Scattered Pilots Without Decision FeedbackJun 02 2016In this paper, we consider an OFDM radio link corrupted by oscillator phase noise in the receiver, namely the problem of estimating and compensating for the impairment. To lessen the computational burden and delay incurred onto the receiver, we estimate ... More
Reuse of Neural Modules for General Video Game PlayingDec 04 2015A general approach to knowledge transfer is introduced in which an agent controlled by a neural network adapts how it reuses existing networks as it learns in a new domain. Networks trained for a new domain can improve their performance by routing activation ... More
Low missing mass, single- and double diffraction dissociation at the LHCNov 26 2012Low missing mass, single- and double diffraction dissociation is calculated for the LHC energies from a dual-Regge model, dominated by a Pomeron Regge pole exchange. The model reproduces the rich resonance structure in the low missing mass Mx region. ... More
A new mechanism of hypersensitive transport in tilted sharp ratchets induced by noise flatnessMar 24 2003May 18 2003The noise-flatness-induced hypersensitive transport of overdamped Brownian particles in a tilted ratchet system driven by multiplicative nonequilibrium three-level Markovian noise and additive white noise is considered. At low temperatures the enhancement ... More
Functional Generative Design of Mechanisms with Recurrent Neural Networks and Novelty SearchMar 25 2019Consumer-grade 3D printers have made it easier to fabricate aesthetic objects and static assemblies, opening the door to automated design of such objects. However, while static designs are easily produced with 3D printing, functional designs with moving ... More
Myopic Policy Bounds for Information Acquisition POMDPsJan 27 2016This paper addresses the problem of optimal control of robotic sensing systems aimed at autonomous information gathering in scenarios such as environmental monitoring, search and rescue, and surveillance and reconnaissance. The information gathering problem ... More
On Number of Almost Blank Subframes in Heterogeneous Cellular NetworksApr 08 2013Aug 09 2013In heterogeneous cellular scenarios with macrocells, femtocells or picocells users may suffer from significant co-channel cross-tier interference. To manage this interference 3GPP introduced almost blank subframe (ABSF), a subframe in which the interferer ... More
Besicovitch-Federer projection theorem and geodesic flows on Riemann surfacesApr 18 2011Dec 12 2012We extend the Besicovitch-Federer projection theorem to transversal families of mappings. As an application we show that on a certain class of Riemann surfaces with constant negative curvature and with boundary, there exist natural 2-dimensional measures ... More
Spin currents driven by the Higgs mode in magnetic superconductorsJul 01 2019Higgs mode in superconducting materials describes slowly-decaying oscillations of the order parameter amplitude. We demonstrate that in magnetic superconductors with built-in spin-splitting field Higgs mode is strongly coupled to the spin degrees of freedom ... More
An information model for modular robots: the Hardware Robot Information Model (HRIM)Feb 05 2018Feb 06 2018Today's landscape of robotics is dominated by vertical integration where single vendors develop the final product leading to slow progress, expensive products and customer lock-in. Opposite to this, an horizontal integration would result in a rapid development ... More
Growth of (110) Diamond using pure DicarbonOct 05 2000We use a density-functional based tight-binding method to study diamond growth steps by depositing dicarbon species onto a hydrogen-free diamond (110) surface. Subsequent C_2 molecules are deposited on an initially clean surface, in the vicinity of a ... More
Turning the LHC Ring into a New Physics Search MachineApr 20 2016Apr 22 2016By combining the LHC Beam Loss Monitoring (BLM) system with the LHC experiments, a powerful search machine for new physics beyond the standard model can be realised. The pair of final state protons in the central production process, exit the LHC beam ... More
Towards self-adaptable robots: from programming to training machinesFeb 12 2018We argue that hardware modularity plays a key role in the convergence of Robotics and Artificial Intelligence (AI). We introduce a new approach for building robots that leads to more adaptable and capable machines. We present the concept of a self-adaptable ... More
On Covers of Dihedral 2-Groups by Powerful SubgroupsJan 10 2019A finite $p$-group $G$ is called \textit{powerful} if either $p$ is odd and $[G,G]\subseteq G^p$ or $p=2$ and $[G,G]\subseteq G^4$. A {\em{cover}} for a group is a collection of subgroups whose union is equal to the entire group. We will discuss covers ... More