Results for "Risto Paatelainen"

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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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
Optimizing Gaze Direction in a Visual Navigation TaskFeb 16 2016Navigation in an unknown environment consists of multiple separable subtasks, such as collecting information about the surroundings and navigating to the current goal. In the case of pure visual navigation, all these subtasks need to utilize the same ... 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
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
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
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 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
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
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
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
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
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
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
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
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
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
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
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
Diffusion and Current of Brownian Particles in Tilted Piecewise Linear Potentials: Amplification and CoherenceFeb 01 2004Overdamped motion of Brownian particles in tilted piecewise linear periodic potentials is considered. Explicit algebraic expressions for the diffusion coefficient, current, and coherence level of Brownian transport are derived. Their dependencies on temperature, ... 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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
Electron transport through quantum wires and point contactsJun 07 2004We have studied quantum wires using the Green's function technique and the density-functional theory, calculating the electronic structure and the conductance. All the numerics are implemented using the finite-element method with a high-order polynomial ... 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
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
Soft Classification of Diffractive Interactions at the LHCDec 30 2010Multivariate machine learning techniques provide an alternative to the rapidity gap method for event-by-event identification and classification of diffraction in hadron-hadron collisions. Traditionally, such methods assign each event exclusively to a ... 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
The aqueous and crystalline forms of L-alanine zwitterionApr 20 2007The structural properties of L-alanine amino acid in aqueous solution and in crystalline phase have been studied by means of density-functional electronic-structure and molecular dynamics simulations. The solvated zwitterionic structure of L-alanine (+NH3-C2H4-COO-) ... More
Photoelectron Emission from Metal Surfaces Induced by Radiation Emitted by a 14 GHz Electron Cyclotron Resonance Ion SourceSep 01 2015Photoelectron emission measurements have been performed using a room-temperature 14 GHz ECR ion source. It is shown that the photoelectron emission from Al, Cu, and stainless steel (SAE 304) surfaces, which are common plasma chamber materials, is predominantly ... More
Modeling and Efficient Cancellation of Nonlinear Self-Interference in MIMO Full-Duplex TransceiversJun 03 2014Oct 10 2014This paper addresses the modeling and digital cancellation of self-interference in in-band full-duplex (FD) transceivers with multiple transmit and receive antennas. The self-interference modeling and the proposed nonlinear spatio-temporal digital canceller ... More
Evolutionary Neural AutoML for Deep LearningFeb 18 2019Apr 09 2019Deep neural networks (DNNs) have produced state-of-the-art results in many benchmarks and problem domains. However, the success of DNNs depends on the proper configuration of its architecture and hyperparameters. Such a configuration is difficult and ... More
In-Band Full-Duplex Wireless: Challenges and OpportunitiesNov 03 2013May 20 2014In-band full-duplex (IBFD) operation has emerged as an attractive solution for increasing the throughput of wireless communication systems and networks. With IBFD, a wireless terminal is allowed to transmit and receive simultaneously in the same frequency ... More
Spin dependent electron transport through a magnetic resonant tunneling diodeNov 24 2004Electron transport properties in nanostructures can be modeled, for example, by using the semiclassical Wigner formalism or the quantum mechanical Green's functions formalism. We compare the performance and the results of these methods in the case of ... More
Fast convergence to equilibrium for long-chain polymer melts using a MD/continuum hybrid methodMay 30 2012Effective and fast convergence toward an equilibrium state for long-chain polymer melts is realized by a hybrid method coupling molecular dynamics and the elastic continuum. The required simulation time to achieve the equilibrium state is reduced drastically ... More
Dissecting Robotics - historical overview and future perspectivesApr 27 2017Robotics is called to be the next technological revolution and estimations indicate that it will trigger the fourth industrial revolution. This article presents a review of some of the most relevant milestones that occurred in robotics over the last few ... More
Kohn-Sham decomposition in real-time time-dependent density-functional theory: An efficient tool for analyzing plasmonic excitationsMar 08 2017The real-time-propagation formulation of time-dependent density-functional theory (RT-TDDFT) is an efficient method for modeling the optical response of molecules and nanoparticles. Compared to the widely adopted linear-response TDDFT approaches based ... More
Fast k-NN searchSep 23 2015Aug 19 2016Efficient index structures for fast approximate nearest neighbor queries are required in many applications such as recommendation systems. In high-dimensional spaces, many conventional methods suffer from excessive usage of memory and slow response times. ... More
Robot_gym: accelerated robot training through simulation in the cloud with ROS and GazeboAug 30 2018Rather than programming, training allows robots to achieve behaviors that generalize better and are capable to respond to real-world needs. However, such training requires a big amount of experimentation which is not always feasible for a physical robot. ... More
Nanoplasmonics simulations at the basis set limit through completeness-optimized, local numerical basis setsSep 03 2015We present an approach for generating local numerical basis sets of improving accuracy for first-principles nanoplasmonics simulations within time-dependent density functional theory. The method is demonstrated for copper, silver, and gold nanoparticles ... More
Challenges in Truncating the Hierarchy of Time-Dependent Reduced Density Matrices Equations: Open ProblemsApr 19 2012In this work, we analyze the Born, Bogoliubov, Green, Kirkwood and Yvon (BBGKY) hierarchy of equations for describing the full time-evolution of a many-body fermionic system in terms of its reduced density matrices (at all orders). We provide an exhaustive ... More
Multivariate Techniques for Identifying Diffractive Interactions at the LHCSep 16 2009Close to one half of the LHC events are expected to be due to elastic or inelastic diffractive scattering. Still, predictions based on extrapolations of experimental data at lower energies differ by large factors in estimating the relative rate of diffractive ... More
Asymptotic Analysis of SU-MIMO Channels With Transmitter Noise and Mismatched Joint DecodingJun 19 2014Oct 22 2014Hardware impairments in radio-frequency components of a wireless system cause unavoidable distortions to transmission that are not captured by the conventional linear channel model. In this paper, a 'binoisy' single-user multiple-input multiple-output ... More
Adsorption of metal impurities on H-terminated Si surfaces and their influence on the wet chemical etching of SiJul 10 2008We use first-principles methods to investigate the adsorption of Cu, Pb, Ag, and Mg onto a H-terminated Si surface. We show that Cu and Pb can adsorb strongly while Ag and Mg are fairly inert. In addition, two types of adsorption states are seen to exist ... More
Quantized evolution of the plasmonic response in a stretched nanorodSep 03 2015Dec 07 2015Quantum aspects, such as electron tunneling between closely separated metallic nanoparticles, are crucial for understanding the plasmonic response of nanoscale systems. We explore quantum effects on the response of the conductively coupled metallic nanoparticle ... More
First principles electron transport: finite-element implementation for nanostructuresJun 20 2005We have modeled transport properties of nanostructures using the Green's function method within the framework of the density-functional theory. The scheme is computationally demanding so that numerical methods have to be chosen carefully. A typical solution ... More
Measurement of the energy distribution of electrons escaping minimum-B ECR plasmasNov 15 2017The measurement of the electron energy distribution (EED) of electrons escaping axially from a minimum-B electron cyclotron resonance ion source (ECRIS) is reported. The experimental data were recorded with a room-temperature 14 GHz ECRIS at the JYFL ... More
Evolutionary Neural AutoML for Deep LearningFeb 18 2019Feb 21 2019Deep neural networks (DNNs) have produced state-of-the-art results in many benchmarks and problem domains. However, the success of DNNs depends on the proper configuration of its architecture and hyperparameters. Such a configuration is difficult and ... More
Forward Physics with Rapidity Gaps at the LHCNov 02 2008Aug 03 2009A rapidity gap program with great potential can be realized at the Large Hadron Collider, LHC, by adding a few simple forward shower counters (FSCs) along the beam line on both sides of the main central detectors, such as CMS. Measurements of single diffractive ... More
Conversion Rate Optimization through Evolutionary ComputationMar 01 2017Apr 30 2017Conversion optimization means designing a web interface so that as many users as possible take a desired action on it, such as register or purchase. Such design is usually done by hand, testing one change at a time through A/B testing, or a limited number ... More
Advanced Self-interference Cancellation and Multiantenna Techniques for Full-Duplex RadiosJan 14 2014In an in-band full-duplex system, radios transmit and receive simultaneously in the same frequency band at the same time, providing a radical improvement in spectral efficiency over a half-duplex system. However, in order to design such a system, it is ... More