Results for "Gianluigi Catelani"

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Exchange-interaction of two spin qubits mediated by a superconductorSep 21 2015Entangling two quantum bits by letting them interact is the crucial requirements for building a quantum processor. For qubits based on the spin of the electron, these two-qubit gates are typically performed by exchange interaction of the electrons captured ... More
Efficient quasiparticle traps with low dissipation through gap engineeringJul 10 2019Quasiparticles represent an intrinsic source of perturbation for superconducting qubits, leading to both dissipation of the qubit energy and dephasing. Recently, it has been shown that normal-metal traps may efficiently reduce the quasiparticle population ... More
Interaction corrections: temperature and parallel field dependencies of the Lorentz number in two-dimensional disordered metalsOct 12 2006Jan 31 2007The electron-electron interaction corrections to the transport coefficients are calculated for a two-dimensional disordered metal in a parallel magnetic field via the quantum kinetic equation approach. For the thermal transport, three regimes (diffusive, ... More
Parity switching and decoherence by quasiparticles in single-junction transmonsJan 22 2014The transmon superconducting qubit is being intensely investigated as a promising approach for the physical implementation of quantum information processing, and high quality factors of order $10^6$ have been achieved both in two- and three-dimensional ... More
Superheating field of superconductors within Ginzburg-Landau theoryAug 26 2010We study the superheating field of a bulk superconductor within Ginzburg-Landau theory, which is valid near the critical temperature. We calculate, as functions of the Ginzburg-Landau parameter $\kappa$, the superheating field $\Hsh$ and the critical ... More
Measurement and Control of Quasiparticle Dynamics in a Superconducting QubitJun 27 2014Oct 24 2014Superconducting circuits have attracted growing interest in recent years as a promising candidate for fault-tolerant quantum information processing. Extensive efforts have always been taken to completely shield these circuits from external magnetic field ... More
Zeeman-limited Superconductivity in Crystalline Al FilmsMar 10 2017We report the evolution of the Zeeman-mediated superconducting phase diagram (PD) in ultra-thin crystalline Al films. Parallel critical field measurements, down to 50 mK, were made across the superconducting tricritical point of films ranging in thickness ... More
Categorical Proof Theory of Co-Intuitionistic Linear LogicJul 12 2014Sep 19 2014To provide a categorical semantics for co-intuitionistic logic one has to face the fact, noted by Tristan Crolard, that the definition of co-exponents as adjuncts of coproducts does not work in the category Set, where coproducts are disjoint unions. Following ... More
Temperature dependence of the superheating field for superconductors in the high-k London limitOct 26 2008Dec 08 2008We study the metastability of the superheated Meissner state in type II superconductors with k >> 1 beyond Ginzburg-Landau theory, which is applicable only in the vicinity of the critical temperature. Within Eilenberger's semiclassical approximation, ... More
Shielding superconductors with thin filmsJun 28 2015Determining the optimal arrangement of superconducting layers to withstand large amplitude AC magnetic fields is important for certain applications such as superconducting radiofrequency cavities. In this paper, we evaluate the shielding potential of ... More
Effect of Coulomb interaction on current noise in open quantum dotsNov 13 2007We analyze the effect of Coulomb interaction on the noise of electric current through an open quantum dot. We demonstrate that the ensemble average value of the noise power acquires an interaction correction even for a dot coupled to the leads by reflectionless ... More
Interaction corrections to the thermal transport coefficients in disordered metals: quantum kinetic equation approachMay 14 2004We consider the singular electron-electron interaction corrections to the transport coefficients in disordered metals to test the validity of the Wiedemann-Franz law. We develop a local, quantum kinetic equation approach in which the charge and energy ... More
Response to comment on theoretical RF field limits of multilayer coating structures of superconducting resonator cavitiesOct 16 2013A comment to the authors' SRF Conference pre-print [1] was submitted by A. Gurevich to the arXiv [2]. In this response, we show that the arguments used in the comment are not valid. [1] arXiv:1309.3239 [2] arXiv:1309.5626
Flux Qubits with Long Coherence Times for Hybrid Quantum CircuitsMar 16 2014Jul 04 2014We present measurements of superconducting flux qubits embedded in a three dimensional copper cavity. The qubits are fabricated on a sapphire substrate and are measured by coupling them inductively to an on-chip superconducting resonator located in the ... More
Theoretical estimates of maximum fields in superconducting resonant radio frequency cavities: Stability theory, disorder, and laminatesJul 31 2016Oct 26 2016Theoretical limits to the performance of superconductors in high magnetic fields parallel to their surfaces are of key relevance to current and future accelerating cavities, especially those made of new higher-Tc materials such as Nb$_3$Sn, NbN, and MgB$_2$. ... More
Theoretical Field Limits for Multi-Layer SuperconductorsSep 12 2013Sep 16 2013The SIS structure---a thin superconducting film on a bulk superconductor separated by a thin insulating film---was propsed as a method to protect alternative SRF materials from flux penetration by enhancing the first critical field $B_{c1}$. In this work, ... More
Theoretical estimates of maximum fields in superconducting resonant radio frequency cavities: Stability theory, disorder, and laminatesJul 31 2016Aug 03 2016We review our work on theoretical limits to the performance of superconductors in high magnetic fields parallel to their surfaces. These limits are of key relevance to current and future accelerating cavities, especially those made of new higher-$T_c$ ... More
Spin Related Effects in Transport Properties of "Open" Quantum DotsSep 14 2005We study the interaction corrections to the transport coefficients in open quantum dots (i.e. dots connected to leads of large conductance $G \gg e^2/\pi\hbar$), via a quantum kinetic equation approach. The effects of all the channels of the universal ... More
Waiting Times in Simulated Stock MarketsFeb 22 2008Exploiting a precise reproduction of a stock exchange, the robustness of the Continuous Double Auction (CDA) mechanism, evaluated by means of the waiting time distributions, has been proved versus 36 different set ups made by varying both the operators' ... More
Holographic polymer-dispersed liquid crystal Bragg grating integrated inside a solid core photonic crystal fiberNov 04 2013A polymer/liquid crystal-based fiber Bragg grating (PLC-FBG) is fabricated with visible two-beam holography by photo-induced modulation of a pre-polymer/LC solution infiltrated into the hollow channels of a solid core photonic crystal fiber (PCF). The ... More
Tree Projections and Structural Decomposition Methods: Minimality and Game-Theoretic CharacterizationDec 11 2012Tree projections provide a mathematical framework that encompasses all the various (purely) structural decomposition methods that have been proposed in the literature to single out classes of nearly-acyclic (hyper)graphs, such as the tree decomposition ... More
On the Application of Reduced Basis Methods to Bifurcation Problems in Incompressible Fluid DynamicsJan 03 2018In this paper we apply a reduced basis framework for the computation of flow bifurcation (and stability) problems in fluid dynamics. The proposed method aims at reducing the complexity and the computational time required for the construction of bifurcation ... More
Bounding the Uncertainty of Graphical Games: The Complexity of Simple Requirements, Pareto and Strong Nash EquilibriaJul 04 2012We investigate the complexity of bounding the uncertainty of graphical games, and we provide new insight into the intrinsic difficulty of computing Nash equilibria. In particular, we show that, if one adds very simple and natural additional requirements ... More
Reduced basis approaches for parametrized bifurcation problems held by non-linear Von Kármán equationsApr 05 2018This work focuses on the detection of the buckling phenomena and bifurcation analysis of the parametric Von K\'arm\'an plate equations based on reduced order methods and spectral analysis. The computational complexity - due to the fourth order derivative ... More
Certified Reduced Basis Method for Affinely Parametric Isogeometric Analysis NURBS ApproximationOct 17 2017In this work we apply reduced basis methods for parametric PDEs to an isogeometric formulation based on NURBS. The motivation for this work is an integrated and complete work pipeline from CAD to parametrization of domain geometry, then from full order ... More
Reduced formulation of a steady fluid-structure interaction problem with parametric couplingMay 19 2010We propose a two-fold approach to model reduction of fluid-structure interaction. The state equations for the fluid are solved with reduced basis methods. These are model reduction methods for parametric partial differential equations using well-chosen ... More
Choreographies and Behavioural Contracts on the Way to Dynamic UpdatesNov 14 2014We survey our work on choreographies and behavioural contracts in multiparty interactions. In particular theories of behavioural contracts are presented which enable reasoning about correct service composition (contract compliance) and service substitutability ... More
Mechanisms for Fair Allocation Problems: No-Punishment Payment Rules in Fully Verifiable SettingsSep 15 2012Mechanism design is addressed in the context of fair allocations of indivisible goods with monetary compensation. Motivated by a real-world social choice problem, mechanisms with verification are considered in a setting where (i) agents' declarations ... More
User Preferences Modeling and Learning for Pleasing Photo Collage GenerationJun 01 2015In this paper we consider how to automatically create pleasing photo collages created by placing a set of images on a limited canvas area. The task is formulated as an optimization problem. Differently from existing state-of-the-art approaches, we here ... More
Reduced basis approaches for parametrized bifurcation problems held by non-linear Von Kármán equationsApr 05 2018Jun 22 2019This work focuses on the detection of the buckling phenomena and bifurcation analysis of the parametric Von K\'arm\'an plate equations based on reduced order methods and spectral analysis. The computational complexity - due to the fourth order derivative ... More
Tunable superconducting nanoinductorsJul 23 2010Sep 27 2010We characterize inductors fabricated from ultra-thin, approximately 100 nm wide strips of niobium (Nb) and niobium nitride (NbN). These nanowires have a large kinetic inductance in the superconducting state. The kinetic inductance scales linearly with ... More
On The Power of Tree Projections: Structural Tractability of Enumerating CSP SolutionsMay 10 2010Jun 30 2010The problem of deciding whether CSP instances admit solutions has been deeply studied in the literature, and several structural tractability results have been derived so far. However, constraint satisfaction comes in practice as a computation problem ... More
Greedy Strategies and Larger Islands of Tractability for Conjunctive Queries and Constraint Satisfaction ProblemsMar 31 2016Jul 04 2016Structural decomposition methods have been developed for identifying tractable classes of instances of fundamental problems in databases, such as conjunctive queries and query containment, of the constraint satisfaction problem in artificial intelligence, ... More
Tree Projections and Structural Decomposition Methods: The Power of Local Consistency and Larger Islands of TractabilityMay 15 2012Dec 28 2012Evaluating conjunctive queries and solving constraint satisfaction problems are fundamental problems in database theory and artificial intelligence, respectively. These problems are NP-hard, so that several research efforts have been made in the literature ... More
THE VELOCITY OF THE EMITTING PLASMA OF THE SUPERLUMINAL GALACTIC SOURCE GRS 1915+105Jan 12 1995We calculate the flux and size ratio of radio emitting features moving in antiparallel directions at relativistic speeds, taking into account that the pattern we observe may move at a velocity different from the one of the emitting plasma. Both velocities ... More
Ride Sharing with a Vehicle of Unlimited CapacityJul 09 2015Jun 09 2016A ride sharing problem is considered where we are given a graph, whose edges are equipped with a travel cost, plus a set of objects, each associated with a transportation request given by a pair of origin and destination nodes. A vehicle travels through ... More
Efficient Geometrical parametrization for finite-volume based reduced order methodsJan 18 2019In this work we present a new approach for the efficient treatment of parametrized geometries in the context of POD-Galerkin reduced order methods based on Finite Volume full order approximations. On the contrary to what is normally done in the framework ... More
Jupiter's North Equatorial Belt and Jet: III, The 'great northern upheaval' in 2012Sep 25 2018In Paper II we described the extreme changes in Jupiter's North Equatorial Belt (NEB) which took place in 2011-12: quiescence, narrowing, and fading of the belt, along with acceleration of the prograde NEBs jet to super-fast speed. Here we describe how ... More
A Cointuitionistic Adjoint LogicAug 19 2017One leading question with respect to Bi-intuitionistic logic (BINT) is, what does BINT look like across the three arcs -- logic, typed $\lambda$-calculi, and category theory -- of the Curry-Howard-Lambek correspondence? Categorically, BINT can be seen ... More
Dissipation in a superconducting artificial atom due to a single non-equilibrium quasiparticleSep 01 2017We study a superconducting artificial atom which is represented by a single Josephson junction or a Josephson junction chain, capacitively coupled to a coherently driven transmission line, and which contains exactly one residual quasiparticle (or up to ... More
Superconducting RF Technology R&D for Future Accelerator ApplicationsAug 09 2012Dec 17 2012Superconducting rf technology (SRF) is evolving rapidly as are its applications. While there is active exploitation of what one may term the current state-of-the-practice, there is also rapid progress expanding in several dimensions the accessible and ... More
A local ergodic theorem for non-uniformly hyperbolic symplectic maps with singularitiesOct 06 2010Mar 12 2012In this paper, we prove a criterion for the local ergodicity of non-uniformly hyperbolic symplectic maps with singularities. Our result is an extension of a theorem of Liverani and Wojtkowski.
Quasiparticle dynamics in granular aluminum close to the superconductor to insulator transitionFeb 06 2018Feb 07 2018Superconducting high kinetic inductance elements constitute a valuable resource for quantum circuit design and millimeter-wave detection. Granular aluminum (GrAl) in the superconducting regime is a particularly interesting material since it has already ... More
Effect of Quasiparticles Injection on the AC Response of a SuperconductorJul 08 2010We calculate the AC linear response of a superconductor in a nonequilibrium electronic state. The nonequilibrium state is produced by injecting quasiparticles into the superconductor from normal leads through asymmetric tunnel contacts. The dissipative ... More
Fermi-liquid effects in the gapless state of marginally thin superconducting filmsSep 24 2008We present low temperature tunneling density-of-states measurements in Al films in high parallel magnetic fields. The thickness range of the films, t=6-9 nm, was chosen so that the orbital and Zeeman contributions to their parallel critical fields were ... More
Spin-Resolved Tunneling Studies of the Exchange Field in EuS/Al BilayersMay 18 2011We use spin-resolved electron tunneling to study the exchange field in the Al component of EuS/Al bilayers, in both the superconducting and normal-state phases of the Al. Contrary to expectation, we show that the exchange field, Hex, is a non-linear function ... More
Tunneling anomaly of superconducting films in strong magnetic fieldsJan 17 2006We consider the tunneling Density of States (DoS) of superconducting films driven to the paramagnetic phase by the Zeeman splitting. We show that there is minimum in the DoS whose position depends on the orientation of the applied field. This dependence, ... More
Saturation of the Anomalous Hall Effect in Critically Disordered Ultra-thin CNi3 FilmsJan 31 2010We demonstrate that a distinct high-disorder anomalous Hall effect phase emerges at the correlated insulator threshold of ultra-thin, amorphous, ferromagnetic CNi3 films. In the weak localization regime, where the sheet conductance G >> e^2/h, the anomalous ... More
Measurement of Conduction Electron Polarization Via the Pairing ResonanceJul 10 2009We show that the pairing resonance in the Pauli-limited normal state of ultra-thin superconducting Al films provides a spin-resolved probe of conduction electron polarization in thin magnetic films. A superconductor-insulator-ferromagnet tunneling junction ... More
On the signature of tensile blobs in the scattering function of a stretched polymerAug 29 1997We present Monte Carlo data for a linear chain with excluded volume subjected to a uniform stretching. Simulation of long chains (up to 6000 beads) at high stretching allows us to observe the signature of tensile blobs as a crossover in the scaling behavior ... More
Undecidability of Asynchronous Session SubtypingNov 15 2016The most prominent proposals of subtyping for asynchronous session types are by Mostrous and Yoshida for binary sessions, by Chen et al. for binary sessions under the assumption that every message emitted is eventually consumed, and by Mostrous et al. ... More
Ultra-Sparse Non-Binary LDPC Codes for Probabilistic Amplitude ShapingAug 18 2017This work shows how non-binary low-density parity-check codes over GF($2^p$) can be combined with probabilistic amplitude shaping (PAS) (B\"ocherer, et al., 2015), which combines forward-error correction with non-uniform signaling for power-efficient ... More
Client-server multi-task learning from distributed datasetsDec 22 2008Jan 11 2010A client-server architecture to simultaneously solve multiple learning tasks from distributed datasets is described. In such architecture, each client is associated with an individual learning task and the associated dataset of examples. The goal of the ... More
A novel Multiplicative Polynomial Kernel for Volterra series identificationMay 20 2019Volterra series are especially useful for nonlinear system identification, also thanks to their capability to approximate a broad range of input-output maps. However, their identification from a finite set of data is hard, due to the curse of dimensionality. ... More
Flux expulsion in niobium superconducting radio-frequency cavities of different purity and essential contributions to the flux sensitivityJun 06 2019Magnetic flux trapped during the cooldown of superconducting radio-frequency cavities through the transition temperature due to incomplete Meissner state is known to be a significant source of radio-frequency losses. The sensitivity of flux trapping depends ... More
Ultrametricity of optimal transport substates for multiple interacting paths over a square lattice networkNov 15 2016We model a set of point-to-point transports on a network as a system of polydisperse interacting self-avoiding walks (SAWs) over a finite square lattice. The ends of each SAW may be located both at random, uniformly distributed, positions or with one ... More
Parameterized Verification of Safety Properties in Ad Hoc Network ProtocolsAug 09 2011We summarize the main results proved in recent work on the parameterized verification of safety properties for ad hoc network protocols. We consider a model in which the communication topology of a network is represented as a graph. Nodes represent states ... More
Minimal founded semantics for disjunctive logic programs and deductive databasesDec 15 2003In this paper, we propose a variant of stable model semantics for disjunctive logic programming and deductive databases. The semantics, called minimal founded, generalizes stable model semantics for normal (i.e. non disjunctive) programs but differs from ... More
On the efficiency of particle acceleration by rotating magnetospheres in AGNSep 12 2006Mar 16 2007To investigate the efficiency of centrifugal acceleration of particles as a possible mechanism for the generation of ultra-high $\gamma$-ray nonthermal emission from TeV blazars, we study the centrifugal acceleration of electrons by rotating magnetic ... More
Boosting as a kernel-based methodAug 08 2016Boosting is an important learning technique for classification and regression. In this paper, we show a connection between boosting and kernel based methods, highlighting both theoretical and practical applications. In the context of $\ell_2$ boosting, ... More
Identification of stable models via nonparametric prediction error methodsJul 02 2015A new Bayesian approach to linear system identification has been proposed in a series of recent papers. The main idea is to frame linear system identification as predictor estimation in an infinite dimensional space, with the aid of regularization/Bayesian ... More
Protograph-Based LDPC Code Design for Shaped Bit-Metric DecodingApr 14 2015A protograph-based low-density parity-check (LDPC) code design technique for bandwidth-efficient coded modulation is presented. The approach jointly optimizes the LDPC code node degrees and the mapping of the coded bits to the bit-interleaved coded modulation ... More
Bit-Metric Decoding of Non-Binary LDPC Codes with Probabilistic Amplitude ShapingSep 11 2018A new approach for combining non-binary low-density parity-check (NB-LDPC) codes with higher-order modulation and probabilistic amplitude shaping (PAS) is presented. Instead of symbol-metric decoding (SMD), a bit-metric decoder (BMD) is used so that matching ... More
CURL: Co-trained Unsupervised Representation Learning for Image ClassificationMay 29 2015Sep 11 2015In this paper we propose a strategy for semi-supervised image classification that leverages unsupervised representation learning and co-training. The strategy, that is called CURL from Co-trained Unsupervised Representation Learning, iteratively builds ... More
Dust Emission from Quasars and Quasar Host GalaxiesFeb 04 1999We test emission models of circum-nuclear dust torii around quasars, at low and high redshifts, by using a large collection of photometric data for an unbiased sample of 120 optically-selected objects with millimetric and sub-millimetric fluxes, including ... More
Combined parameter and model reduction of cardiovascular problems by means of active subspaces and POD-Galerkin methodsNov 29 2017Mar 20 2018In this chapter we introduce a combined parameter and model reduction methodology and present its application to the efficient numerical estimation of a pressure drop in a set of deformed carotids. The aim is to simulate a wide range of possible occlusions ... More
Computational reduction strategies for the detection of steady bifurcations in incompressible fluid-dynamics: applications to Coanda effect in cardiologyAug 31 2017We focus on reducing the computational costs associated with the hydrodynamic stability of solutions of the incompressible Navier-Stokes equations for a Newtonian and viscous fluid in contraction-expansion channels. In particular, we are interested in ... More
Bayesian kernel-based system identification with quantized output dataApr 26 2015In this paper we introduce a novel method for linear system identification with quantized output data. We model the impulse response as a zero-mean Gaussian process whose covariance (kernel) is given by the recently proposed stable spline kernel, which ... More
Coded Slotted ALOHA: A Graph-Based Method for Uncoordinated Multiple AccessJan 08 2014Sep 30 2015In this paper, a random access scheme is introduced which relies on the combination of packet erasure correcting codes and successive interference cancellation (SIC). The scheme is named coded slotted ALOHA. A bipartite graph representation of the SIC ... More
A Spectral Element Reduced Basis Method for Navier-Stokes Equations with Geometric VariationsDec 28 2018We consider the Navier-Stokes equations in a channel with a narrowing of varying height. The model is discretized with high-order spectral element ansatz functions, resulting in 6372 degrees of freedom. The steady-state snapshot solutions define a reduced ... More
On the Boundary between Decidability and Undecidability of Asynchronous Session SubtypingMar 02 2017Feb 12 2018Session types are behavioural types for guaranteeing that concurrent programs are free from basic communication errors. Recent work has shown that asynchronous session subtyping is undecidable. However, since session types have become popular in mainstream ... More
A Finite Volume approximation of the Navier-Stokes equations with nonlinear filtering stabilizationJan 16 2019We consider a Leray model with a nonlinear differential low-pass filter for the simulation of incompressible fluid flow at moderately large Reynolds number (in the range of a few thousands) with under-refined meshes. For the implementation of the model, ... More
Projection-based reduced order models for a cut finite element method in parametrized domainsJan 12 2019This work presents a reduced order modelling technique built on a high fidelity embedded mesh finite element method. Such methods, and in particular the CutFEM method, are attractive in the generation of projection-based reduced order models thanks to ... More
Interplay between kinetic inductance, non-linearity and quasiparticle dynamics in granular aluminum MKIDsOct 29 2018Nov 10 2018Microwave kinetic inductance detectors (MKIDs) are thin film, cryogenic, superconducting resonators. Incident Cooper pair-breaking radiation increases their kinetic inductance, thereby measurably lowering their resonant frequency. For a given resonant ... More
Non-Poissonian Quantum Jumps of a Fluxonium Qubit due to Quasiparticle ExcitationsJun 06 2014Dec 09 2014As the energy relaxation time of superconducting qubits steadily improves, non-equilibrium quasiparticle excitations above the superconducting gap emerge as an increasingly relevant limit for qubit coherence. We measure fluctuations in the number of quasiparticle ... More
A Path to Higher Q0 with Large Grain Niobium CavitiesMay 30 2012The improvement of the quality factor Q0 of superconducting radio-frequency (SRF) cavities at medium accelerating gradients (20-25 MV/m) is important in order to reduce the cryogenic losses in continuous wave (CW) accelerators used for a variety of applications. ... More
High Throughput Random Access via Codes on Graphs: Coded Slotted ALOHAFeb 12 2011In this paper, coded slotted ALOHA (CSA) is introduced as a powerful random access scheme to the MAC frame. In CSA, the burst a generic user wishes to transmit in the MAC frame is first split into segments, and these segments are then encoded through ... More
Dark spots along slowly scaling chains of plasmonic nanoparticlesMay 28 2016We numerically investigate the optical response of slowly scaling linear chains of mismatched silver nanoparticles. Hybridized plasmon chain resonances manifest unusual local field distributions around the nanoparticles that result from symmetry breaking ... More
Maximum Entropy Vector Kernels for MIMO system identificationAug 12 2015Sep 29 2016Recent contributions have framed linear system identification as a nonparametric regularized inverse problem. Relying on $\ell_2$-type regularization which accounts for the stability and smoothness of the impulse response to be estimated, these approaches ... More
Bayesian and regularization approaches to multivariable linear system identification: the role of rank penaltiesSep 29 2014Recent developments in linear system identification have proposed the use of non-parameteric methods, relying on regularization strategies, to handle the so-called bias/variance trade-off. This paper introduces an impulse response estimator which relies ... More
Track billiardsJun 04 2008We study a class of planar billiards having the remarkable property that their phase space consists up to a set of zero measure of two invariant sets formed by orbits moving in opposite directions. The tables of these billiards are tubular neighborhoods ... More
Tractable Optimization Problems through Hypergraph-Based Structural RestrictionsSep 15 2012Several variants of the Constraint Satisfaction Problem have been proposed and investigated in the literature for modelling those scenarios where solutions are associated with some given costs. Within these frameworks computing an optimal solution is ... More
Protograph-Based LDPC Code Design for Bit-Metric DecodingJan 22 2015A protograph-based low-density parity-check (LDPC) code design technique for bandwidth-efficient coded modulation is presented. The approach jointly optimizes the LDPC code node degrees and the mapping of the coded bits to the bit-interleaved coded modulation ... More
LT Code Design for Inactivation DecodingAug 12 2014We present a simple model of inactivation decoding for LT codes which can be used to estimate the decoding complexity as a function of the LT code degree distribution. The model is shown to be accurate in variety of settings of practical importance. The ... More
How Far Can You Get By Combining Change Detection Algorithms?May 12 2015Apr 04 2018Given the existence of many change detection algorithms, each with its own peculiarities and strengths, we propose a combination strategy, that we termed IUTIS (In Unity There Is Strength), based on a genetic Programming framework. This combination strategy ... More
Outlier Detection by Logic ProgrammingSep 09 2004Oct 13 2005The development of effective knowledge discovery techniques has become in the recent few years a very active research area due to the important impact it has in several relevant application areas. One interesting task thereof is that of singling out anomalous ... More
Finite Length Analysis of Irregular Repetition Slotted ALOHA in the Waterfall RegionMar 04 2018A finite length analysis is introduced for irregular repetition slotted ALOHA (IRSA) that enables to accurately estimate its performance in the moderate-to-high packet loss probability regime, i.e., in the so-called waterfall region. The analysis is tailored ... More
IAT - Image Annotation Tool: ManualFeb 18 2015The annotation of image and video data of large datasets is a fundamental task in multimedia information retrieval and computer vision applications. In order to support the users during the image and video annotation process, several software tools have ... More
Amending ChoreographiesAug 02 2013Choreographies are global descriptions of system behaviors, from which the local behavior of each endpoint entity can be obtained automatically through projection. To guarantee that its projection is correct, i.e. it has the same behaviors of the original ... More
High-Throughput Random Access via Codes on GraphsOct 18 2010Oct 19 2010Recently, contention resolution diversity slotted ALOHA (CRDSA) has been introduced as a simple but effective improvement to slotted ALOHA. It relies on MAC burst repetitions and on interference cancellation to increase the normalized throughput of a ... More
How Far Can You Get By Combining Change Detection Algorithms?May 12 2015Nov 18 2015In this paper we investigate how state-of-the-art change detection algorithms can be combined and used to create a more robust change algorithm leveraging their individual peculiarities. We exploited Genetic Programming (GP) to automatically select the ... More
A new kernel-based approach to system identification with quantized output dataOct 03 2016In this paper we introduce a novel method for linear system identification with quantized output data. We model the impulse response as a zero-mean Gaussian process whose covariance (kernel) is given by the recently proposed stable spline kernel, which ... More
Inactivation Decoding of LT and Raptor Codes: Analysis and Code DesignJun 19 2017In this paper we analyze LT and Raptor codes under inactivation decoding. A first order analysis is introduced, which provides the expected number of inactivations for an LT code, as a function of the output distribution, the number of input symbols and ... More
Inactivation Decoding Analysis for LT CodesOct 28 2015We provide two analytical tools to model the inactivation decoding process of LT codes. First, a model is presented which derives the expected number of inactivations occurring in the decoding process of an LT code. This analysis is then extended allowing ... More
Shape optimization through proper orthogonal decomposition with interpolation and dynamic mode decomposition enhanced by active subspacesMay 14 2019We propose a numerical pipeline for shape optimization in naval engineering involving two different non-intrusive reduced order method (ROM) techniques. Such methods are proper orthogonal decomposition with interpolation (PODI) and dynamic mode decomposition ... More
Stabilized weighted reduced basis methods for parametrized advection dominated problems with random inputsNov 30 2017Nov 02 2018In this work, we propose viable and efficient strategies for stabilized parametrized advection dominated problems, with random inputs. In particular, we investigate the combination of wRB (weighted reduced basis) method for stochastic parametrized problems ... More
A Reduced Order technique to study bifurcating phenomena: application to the Gross-Pitaevskii equationJul 16 2019We are interested in the steady state solution of the Gross-Pitaevskii equation, which describes the ground state of a quantum system of identical bosons under simplifying hypotheses, and their stability properties. Often referred to as a non-linear Schr\"odinger ... More
Atomic-scale tailoring of spin susceptibility via non-magnetic spin-orbit impuritiesNov 13 2018Following the discovery of topological insulators, there has been a renewed interest in superconducting systems that have strong spin-orbit (SO) coupling. Here we address the fundamental question of how the spin properties of a otherwise spin-singlet ... More
Collective modes in the fluxonium qubitJun 29 2015Superconducting qubit designs vary in complexity from single- and few-junction systems, such as the transmon and flux qubits, to the many-junction fluxonium. Here we consider the question of wether the many degrees of freedom in the fluxonium circuit ... More
Photon-assisted charge-parity jumps in a superconducting qubitApr 12 2019We evaluate the rates of energy and phase relaxation of a superconducting qubit caused by stray photons with energy exceeding the threshold for breaking a Cooper pair. All channels of relaxation within this mechanism are associated with the change in ... More