Results for "Danilo Rezende"

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4d Lorentzian Holst action with topological termsFeb 19 2009We study the Hamiltonian formulation of the general first order action of general relativity compatible with local Lorentz invariance and background independence. The most general simplectic structure (compatible with diffeomorphism invariance and local ... More
Taming VAEsOct 01 2018In spite of remarkable progress in deep latent variable generative modeling, training still remains a challenge due to a combination of optimization and generalization issues. In practice, a combination of heuristic algorithms (such as hand-crafted annealing ... More
Variational Inference with Normalizing FlowsMay 21 2015Jun 14 2016The choice of approximate posterior distribution is one of the core problems in variational inference. Most applications of variational inference employ simple families of posterior approximations in order to allow for efficient inference, focusing on ... More
Variational Information Maximisation for Intrinsically Motivated Reinforcement LearningSep 29 2015The mutual information is a core statistical quantity that has applications in all areas of machine learning, whether this is in training of density models over multiple data modalities, in maximising the efficiency of noisy transmission channels, or ... More
Variational inference for Monte Carlo objectivesFeb 22 2016Jun 01 2016Recent progress in deep latent variable models has largely been driven by the development of flexible and scalable variational inference methods. Variational training of this type involves maximizing a lower bound on the log-likelihood, using samples ... More
The theta parameter in loop quantum gravity: effects on quantum geometry and black hole entropyNov 20 2007The precise analog of the theta-quantization ambiguity of Yang-Mills theory exists for the real SU(2) connection formulation of general relativity. As in the former case theta labels representations of large gauge transformations, which are super-selection ... More
The Sturm-Liouville problem and the Polar Representation TheoremJun 29 2010The polar representation theorem for the n-dimensional time-dependent linear Hamiltonian system with continuous coefficients, states that, given two isotropic solutions (Q1, P1) and (Q2, P2), with the identity matrix as Wronskian,the formula Q2 = rcos(f), ... More
Variational Intrinsic ControlNov 22 2016In this paper we introduce a new unsupervised reinforcement learning method for discovering the set of intrinsic options available to an agent. This set is learned by maximizing the number of different states an agent can reliably reach, as measured by ... More
Stochastic Backpropagation and Approximate Inference in Deep Generative ModelsJan 16 2014May 30 2014We marry ideas from deep neural networks and approximate Bayesian inference to derive a generalised class of deep, directed generative models, endowed with a new algorithm for scalable inference and learning. Our algorithm introduces a recognition model ... More
Normalizing Flows on Riemannian ManifoldsNov 07 2016Nov 09 2016We consider the problem of density estimation on Riemannian manifolds. Density estimation on manifolds has many applications in fluid-mechanics, optics and plasma physics and it appears often when dealing with angular variables (such as used in protein ... More
Conditional Neural ProcessesJul 04 2018Deep neural networks excel at function approximation, yet they are typically trained from scratch for each new function. On the other hand, Bayesian methods, such as Gaussian Processes (GPs), exploit prior knowledge to quickly infer the shape of a new ... More
Periodical plane puzzles with numbersJun 06 2011Consider a periodical (in two independent directions) tiling of the plane with polygons (faces). In this article we shall only give examples using squares, regular hexagons, equilateral triangles and parallelograms ("unions" of two equilateral triangles). ... More
A contribution for a mathematical classification of square tilesJun 16 2012In this article we study some geometric properties of a non-trivial square tile (a non-trivial square tile is a non-constant function on a square). Consider infinitely many copies of this single square tile and cover the plane with them, without gaps ... More
Semi-Supervised Learning with Deep Generative ModelsJun 20 2014Oct 31 2014The ever-increasing size of modern data sets combined with the difficulty of obtaining label information has made semi-supervised learning one of the problems of significant practical importance in modern data analysis. We revisit the approach to semi-supervised ... More
Variational Memory Addressing in Generative ModelsSep 21 2017Aiming to augment generative models with external memory, we interpret the output of a memory module with stochastic addressing as a conditional mixture distribution, where a read operation corresponds to sampling a discrete memory address and retrieving ... More
Beyond Greedy Ranking: Slate Optimization via List-CVAEMar 05 2018Feb 23 2019The conventional solution to the recommendation problem greedily ranks individual document candidates by prediction scores. However, this method fails to optimize the slate as a whole, and hence, often struggles to capture biases caused by the page layout ... More
Beyond Greedy Ranking: Slate Optimization via List-CVAEMar 05 2018May 24 2018The conventional approach to solving the recommendation problem is through greedy ranking by prediction scores for individual document candidates. However these methods fail to optimize the slate as a whole, and often struggle at capturing biases caused ... More
Asymptotic estimates for unimodular multilinear forms on sequence spaces with small normsOct 26 2017Mar 19 2019The existence of unimodular forms on sequence spaces with small norms is crucial in a variety of problems in modern analysis. As a consequence of our results, we prove that the optimal solution $f(n_{1},\dots,n_{d})$ for the asymptotic estimate \[ 0<B_{d}\leq\inf\frac{\left\Vert ... More
Constructing a class of solutions for the Hamilton-Jacobi equation in field theorySep 12 2007A new approach leading to the formulation of the Hamilton-Jacobi equation for field theories is investigated within the framework of jet-bundles and multi-symplectic manifolds. An algorithm associating classes of solutions to given sets of boundary conditions ... More
Markov subshifts and partial representation of F_nJul 03 2001In this paper we fix a set \Lambda^* of positive elements of the free group F_n (e.g. the set of finite words occurring in a Markov subshift) as well as n partial isometries on a Hilbert space H. Based on these we define a map S:F_n --> L(H) which we ... More
Interaction Networks for Learning about Objects, Relations and PhysicsDec 01 2016Reasoning about objects, relations, and physics is central to human intelligence, and a key goal of artificial intelligence. Here we introduce the interaction network, a model which can reason about how objects in complex systems interact, supporting ... More
Towards Principled Unsupervised LearningNov 19 2015Dec 03 2015General unsupervised learning is a long-standing conceptual problem in machine learning. Supervised learning is successful because it can be solved by the minimization of the training error cost function. Unsupervised learning is not as successful, because ... More
DRAW: A Recurrent Neural Network For Image GenerationFeb 16 2015May 20 2015This paper introduces the Deep Recurrent Attentive Writer (DRAW) neural network architecture for image generation. DRAW networks combine a novel spatial attention mechanism that mimics the foveation of the human eye, with a sequential variational auto-encoding ... More
Stream cipher based on quasigroup string transformations in $Z_p^*$Mar 30 2004Apr 22 2004In this paper we design a stream cipher that uses the algebraic structure of the multiplicative group $\bbbz_p^*$ (where p is a big prime number used in ElGamal algorithm), by defining a quasigroup of order $p-1$ and by doing quasigroup string transformations. ... More
The Crossed Product by a Partial Endomorphism and the Covariance AlgebraMar 21 2005Given a local homeomorphism \sigma:U -> X where U is a clopen subset of an compact and Hausdorff topological space X, we obtain the possible transfer operators L_\rho which may occur for \al:C(X) -> C(U) given by \al(f)=f\sigma. We obtain examples of ... More
Partial group algebra with projections and relationsAug 03 2018We introduce the notion of the partial group algebra with projections and relations and show that this C*-algebra is a partial crossed product. Examples of partial group algebras with projections and relations are the Cuntz-Krieger algebras and the unitization ... More
Existence of solutions for Hamiltonian field theories by the Hamilton-Jacobi techniqueJul 12 2010The paper is devoted to prove the existence of a local solution of the Hamilton-Jacobi equation in field theory, whence the general solution of the field equations can be obtained. The solution is adapted to the choice of the submanifold where the initial ... More
Unsupervised Learning of 3D Structure from ImagesJul 03 2016A key goal of computer vision is to recover the underlying 3D structure from 2D observations of the world. In this paper we learn strong deep generative models of 3D structures, and recover these structures from 3D and 2D images via probabilistic inference. ... More
Generative Temporal Models with Spatial Memory for Partially Observed EnvironmentsApr 25 2018Jul 19 2018In model-based reinforcement learning, generative and temporal models of environments can be leveraged to boost agent performance, either by tuning the agent's representations during training or via use as part of an explicit planning mechanism. However, ... More
Towards Conceptual CompressionApr 29 2016We introduce a simple recurrent variational auto-encoder architecture that significantly improves image modeling. The system represents the state-of-the-art in latent variable models for both the ImageNet and Omniglot datasets. We show that it naturally ... More
Towards a Definition of Disentangled RepresentationsDec 05 2018How can intelligent agents solve a diverse set of tasks in a data-efficient manner? The disentangled representation learning approach posits that such an agent would benefit from separating out (disentangling) the underlying structure of the world into ... More
Learning models for visual 3D localization with implicit mappingJul 04 2018Dec 12 2018We consider learning based methods for visual localization that do not require the construction of explicit maps in the form of point clouds or voxels. The goal is to learn an implicit representation of the environment at a higher, more abstract level. ... More
One-Shot Generalization in Deep Generative ModelsMar 16 2016May 25 2016Humans have an impressive ability to reason about new concepts and experiences from just a single example. In particular, humans have an ability for one-shot generalization: an ability to encounter a new concept, understand its structure, and then be ... More
Unsupervised Learning of 3D Structure from ImagesJul 03 2016Jun 19 2018A key goal of computer vision is to recover the underlying 3D structure from 2D observations of the world. In this paper we learn strong deep generative models of 3D structures, and recover these structures from 3D and 2D images via probabilistic inference. ... More
Unsupervised Predictive Memory in a Goal-Directed AgentMar 28 2018Animals execute goal-directed behaviours despite the limited range and scope of their sensors. To cope, they explore environments and store memories maintaining estimates of important information that is not presently available. Recently, progress has ... More
Neural ProcessesJul 04 2018A neural network (NN) is a parameterised function that can be tuned via gradient descent to approximate a labelled collection of data with high precision. A Gaussian process (GP), on the other hand, is a probabilistic model that defines a distribution ... More
Consistent Generative Query NetworksJul 05 2018Apr 22 2019Stochastic video prediction models take in a sequence of image frames, and generate a sequence of consecutive future image frames. These models typically generate future frames in an autoregressive fashion, which is slow and requires the input and output ... More
Generative Temporal Models with MemoryFeb 15 2017Feb 21 2017We consider the general problem of modeling temporal data with long-range dependencies, wherein new observations are fully or partially predictable based on temporally-distant, past observations. A sufficiently powerful temporal model should separate ... More
Consistent Jumpy Predictions for Videos and ScenesJul 05 2018Oct 02 2018Stochastic video prediction models take in a sequence of image frames, and generate a sequence of consecutive future image frames. These models typically generate future frames in an autoregressive fashion, which is slow and requires the input and output ... More
Graph C*-algebras, branching systems and the Perron-Frobenius operatorAug 07 2009Jul 03 2014In this paper we show how to produce a large number of representations of a graph C*-algebra in the space of the bounded linear operators in $L^2(X,\mu)$. These representations are very concrete and, in the case of graphs that satisfy condition (K), we ... More
Holographic formula for the determinant of the scattering operator in thermal AdSDec 11 2008Aug 26 2009A 'holographic formula' expressing the functional determinant of the scattering operator in an asymptotically locally anti-de Sitter(ALAdS) space has been proposed in terms of a relative functional determinant of the scalar Laplacian in the bulk. It stems ... More
Artin algebras of finite type and finite categories of $Δ$-good modulesMay 13 2015We give an alternative proof to the fact that if the square of the infinite radical of the module category of an Artin algebra is equal to zero then the algebra is of finite type by making use of the theory of postprojective and preinjective partitions. ... More
Riemann Hypothesis: a special case of the Riesz and Hardy-Littlewood wave and a numerical treatment of the Baez-Duarte coefficients up to some billions in the k-variableSep 17 2006We consider the Riesz and Hardy-Littlewood wave i.e. a ``critical function'' whose behaviour is concerned with the possible truth of the Riemann Hypothesis (RH). The function is studied numerically for the case alpha = 15/2 and beta = 4 in some range ... More
The criteria of Riesz, Hardy-Littlewood et al. for the Riemann Hypothesis revisited using similar functionsJan 07 2006The original criteria of Riesz and of Hardy-Littlewood concerning the truth of the Riemann Hypothesis (RH) are revisited and further investigated in light of the recent formulations and results of Maslanka and of Baez-Duarte concerning a representation ... More
The evolution of the rest-frame J- and H-band luminosity function of galaxies to z=3.5Nov 30 2011Nov 12 2012We present the rest-frame J- and H-band luminosity function (LF) of field galaxies, based on a deep multi-wavelength composite sample from the MUSYC, FIRES and FIREWORKS survey public catalogues, covering a total area of 450 arcmin^2. The availability ... More
Unitary equivalence of representations of graph algebras and branching systemsNov 24 2009In this paper we show that, for a class of countable graphs, every representation of the associated graph algebra in a separable Hilbert space is unitarily equivalent to a representation obtained via branching systems.
Branching systems and representations of Cohn-Leavitt path algebras of separated graphsMar 06 2014We construct for each separated graph (E;C) a family of branching systems over a set X and show how each branching system induces a representation of the Cohn-Leavitt path algebra associated to (E;C) as homomorphisms over the module of functions in X. ... More
On finite groups in which commutators are covered by Engel subgroupsJan 03 2019Let $m,n$ be positive integers and $w$ a multilinear commutator word. Assume that $G$ is a finite group having subgroups $G_1,\ldots,G_m$ whose union contains all $w$-values in $G$. Assume further that all elements of the subgroups $G_1,\ldots,G_m$ are ... More
Statistical inference for time-inhomogeneous volatility modelsJun 22 2004This paper offers a new approach for estimating and forecasting the volatility of financial time series. No assumption is made about the parametric form of the processes. On the contrary, we only suppose that the volatility can be approximated by a constant ... More
Ultragraphs and shifts spaces over infinite alphabetsOct 15 2015Oct 16 2015In this paper we further develop the theory of one sided shift spaces over infinite alphabets, characterizing one-step shifts as edge shifts of ultragraphs and partially answering a conjecture regarding shifts of finite type (we show that there exists ... More
Infinite alphabet edge shift spaces via ultragraphs and their C*-algebrasMar 15 2017May 18 2017We define a notion of (one-sided) edge shift spaces associated to ultragraphs. In the finite case our notion coincides with the edge shift space of a graph. In general, we show that our space is metrizable and has a countable basis of clopen sets. We ... More
Dynamics for a class of polynomial maps in $\mathbb{R}^2$Dec 30 2017In this work we consider a class of endomorphisms of $\mathbb{R}^2$ defined by $f(x,y)=(xy+c,x)$, where $c\in\mathbb{R}$ is a real number and we prove that when $-1<c<0$, the forward (respectively backward) filled Julia set of $f$ is the union of stable ... More
Exploration, inference and prediction in neuroscience and biomedicineFeb 21 2019The last decades saw dramatic progress in brain research. These advances were often buttressed by probing single variables to make circumscribed discoveries, typically through null hypothesis significance testing. New ways for generating massive data ... More
$\mathcal{W}$-algebra constraints and topological recursion for $A_N$-singularityFeb 29 2016We derive a Bouchard--Eynard type topological recursion for the total descendant potential of $A_N$-singularity. Our argument relies on a certain twisted representation of a Heisenberg Vertex Operator Algebra (VOA) constructed via the periods of $A_N$-singularity. ... More
Bounded Engel elements in residually finite groupsDec 11 2018Let $q$ be a prime. Let $G$ be a residually finite group satisfying an identity. Suppose that for every $x \in G$ there exists a $q$-power $m=m(x)$ such that the element $x^m$ is a bounded Engel element. We prove that $G$ is locally virtually nilpotent. ... More
Leavitt path algebras as partial skew group ringsFeb 13 2012We realize Leavitt path algebras as partial skew group rings and give new proofs, based on partial skew group ring theory, of the Cuntz-Krieger uniqueness theorem and simplicity criteria for Leavitt path algebras.
C*-algebras Associated do Stationary Ordered Bratteli DiagramsAug 18 2011Aug 23 2011In this paper, we introduce a C*-algebra associated to any substitution (via its Bratteli diagram model). We show that this C*-algebra contains the partial crossed product C*-algebra of the corresponding Bratteli-Vershik system and show that these algebras ... More
Simplicity and chain conditions for ultragraph Leavitt path algebras via partial skew group ring theoryJun 12 2017Jun 13 2017We realize Leavitt ultragraph path algebras as partial skew group rings. Using this realization we characterize artinian ultragraph path algebras and give simplicity criteria for these algebras.
(M + 1)-step shift spaces that are not conjugate to M-step shift spacesMay 28 2014Jun 27 2014Recently Ott, Tomforde and Willis proposed a new approach for one sided shift spaces over infinite alphabets. In this new approach the conjugacy classes of shifts of finite type, edge shifts, and M-step shifts are distinct and the authors conjecture that ... More
Approaching Maximum Embedding Efficiency on Small Covers Using Staircase-Generator CodesAug 10 2015We introduce a new family of binary linear codes suitable for steganographic matrix embedding. The main characteristic of the codes is the staircase random block structure of the generator matrix. We propose an efficient list decoding algorithm for the ... More
Representations and the reduction theorem for ultragraph Leavitt path algebrasJan 31 2019In this paper we study representations of ultragraph Leavitt path algebras via branching systems and, using partial skew ring theory, prove the reduction theorem for these algebras. We apply the reduction theorem to show that ultragraph Leavitt path algebras ... More
Engel-like conditions in fixed points of automorphisms of profinite groupsFeb 21 2019Let $q$ be a prime and $A$ an elementary abelian $q$-group acting as a coprime group of automorphisms on a profinite group $G$. We show that if $A$ is of order $q^2$ and some power of each element in $C_G(a)$ is Engel in $G$ for any $a\in A^{\#}$, then ... More
Rate of approximation for multivariate sampling Kantorovich operators on some functions spacesNov 09 2014In this paper, the problem of the order of approximation for the multivariate sampling Kantorovich operators is studied. The cases of the uniform approximation for uniformly continuous and bounded functions/signals belonging to Lipschitz classes and the ... More
Dynamical Casimir effect with $δ-δ^{\prime}$ mirrorsJan 22 2016Nov 01 2016We calculate the spectrum and the total rate of created particles for a real massless scalar field in $1+1$ dimensions, in the presence of a partially transparent moving mirror simulated by a Dirac $\delta-\delta^{\prime}$ point interaction. We show that, ... More
A Probabilistic U-Net for Segmentation of Ambiguous ImagesJun 13 2018Jan 29 2019Many real-world vision problems suffer from inherent ambiguities. In clinical applications for example, it might not be clear from a CT scan alone which particular region is cancer tissue. Therefore a group of graders typically produces a set of diverse ... More
Few-shot Autoregressive Density Estimation: Towards Learning to Learn DistributionsOct 27 2017Feb 28 2018Deep autoregressive models have shown state-of-the-art performance in density estimation for natural images on large-scale datasets such as ImageNet. However, such models require many thousands of gradient-based weight updates and unique image examples ... More
Tropical Jucys CoversAug 03 2018Jan 02 2019We study monotone and strictly monotone Hurwitz numbers from a bosonic Fock space perspective. This yields to an interpretation in terms of tropical geometry involving local multiplicities given by Gromov-Witten invariants. Furthermore, this enables us ... More
On the joint distribution of first-passage time and first-passage area of drifted Brownian motionSep 22 2016For drifted Brownian motion $X(t)= x - \mu t + B_t \ (\mu >0)$ starting from $x>0,$ we study the joint distribution of the first-passage time below zero, $\tau(x),$ and the first-passage area, $A(x),$ swept out by $X$ till the time $\tau(x).$ In particular, ... More
Efficient Scheduling for the Massive Random Access Gaussian ChannelMay 16 2019This paper investigates the massive random access Gaussian channel with a focus on small payloads. For this problem, grant-based schemes have been regarded as inefficient due to the necessity of large feedbacks and the use of inefficient scheduling request ... More
Learning and Querying Fast Generative Models for Reinforcement LearningFeb 08 2018A key challenge in model-based reinforcement learning (RL) is to synthesize computationally efficient and accurate environment models. We show that carefully designed generative models that learn and operate on compact state representations, so-called ... More
Generalized Topological Transition MatrixNov 14 2013This article represents a major step in the unification of the theory of algebraic, topological and singular transition matrices by introducing a definition which is a generalization that encompasses all of the previous three. When this more general transition ... More
Spectrum-Diverse Neuroevolution with Unified Neural ModelsJan 06 2019Learning algorithms are being increasingly adopted in various applications. However, further expansion will require methods that work more automatically. To enable this level of automation, a more powerful solution representation is needed. However, by ... More
Security for Wiretap Networks via Rank-Metric CodesDec 29 2007May 02 2008The problem of securing a network coding communication system against a wiretapper adversary is considered. The network implements linear network coding to deliver $n$ packets from source to each receiver, and the wiretapper can eavesdrop on $\mu$ arbitrarily ... More
Fast Encoding and Decoding of Gabidulin CodesJan 16 2009Apr 05 2009Gabidulin codes are the rank-metric analogs of Reed-Solomon codes and have a major role in practical error control for network coding. This paper presents new encoding and decoding algorithms for Gabidulin codes based on low-complexity normal bases. In ... More
Assessing the Predictive Power of Galaxy Formation Models with the Rest-Frame Optical Luminosity Functions at 2.0<z<3.3Jan 10 2008We compare recently measured rest-frame V-band luminosity functions (LFs) of galaxies at redshifts 2.0<z<3.3 to predictions of semianalytic models by De Lucia & Blaizot and Bower et al. and hydrodynamic simulations by Dave et al. The models succeed for ... More
Assessing the Predictive Power of Galaxy Formation Models: A Comparison of Predicted and Observed Rest-Frame Optical Luminosity Functions at 2.0<z<3.3May 29 2007Jan 07 2008Recent galaxy formation models successfully reproduce the local luminosity function (LF) of galaxies by invoking mechanisms to suppress star formation in low- and high-mass galaxies. As these models are optimized to fit the LF at low redshift, a crucial ... More
AdS Chern-Simons Gravity induces Conformal GravityNov 21 2013Dec 25 2013The leitmotif of this paper is the question of whether four- and higher even-dimensional Conformal Gravities do have a Chern-Simons pedigree. We show that Weyl gravity can be obtained as dimensional reduction of a five-dimensional Chern-Simons action ... More
Partition functions and double-trace deformations in AdS/CFTFeb 20 2007Feb 19 2008We study the effect of a relevant double-trace deformation on the partition function (and conformal anomaly) of a CFT at large N and its dual picture in AdS. Three complementary previous results are brought into full agreement with each other: bulk and ... More
On the AdS Higher Spin / O(N) Vector Model Correspondence: degeneracy of the holographic imageMar 10 2006May 04 2006We explore the conjectured duality between the critical O(N) vector model and minimal bosonic massless higher spin (HS) theory in AdS. In the boundary free theory, the conformal partial wave expansion (CPWE) of the four-point function of the scalar singlet ... More
Determinant and Weyl anomaly of Dirac operator: a holographic derivationNov 07 2011Nov 18 2011We present a holographic formula relating functional determinants: the fermion determinant in the one-loop effective action of bulk spinors in an asymptotically locally AdS background, and the determinant of the two-point function of the dual operator ... More
A Self-Consistent Extrapolation Method for the Complex Permittivity and Permeability Based on Finite Frequency DataFeb 14 2014Dec 04 2014We describe a method of extrapolation based on a "truncated" Kramers-Kronig relation for the complex permittivity ($\epsilon$) and permeability ($\mu$) parameters of a material, based on finite frequency data. Considering a few assumptions, such as the ... More
An experimental comparison of label selection methods for hierarchical document clustersMay 24 2018The focus of this paper is on the evaluation of sixteen labeling methods for hierarchical document clusters over five datasets. All of the methods are independent from clustering algorithms, applied subsequently to the dendrogram construction and based ... More
A summability principle and applicationsApr 09 2019The main result of the present paper is a new Inclusion Theorem for summing operators, that encompasses several recent similar results as particular cases. As applications, we improve estimates of certain Hardy--Littlewood inequalities for multilinear ... More
Casimir force between $δ-δ^{\prime}$ mirrors transparent at high frequenciesJul 21 2016Aug 14 2016We investigate, in the context of a real massless scalar field in $1+1$ dimensions, models of partially reflecting mirrors simulated by Dirac $\delta-\delta^{\prime}$ point interactions. In the literature, these models do not exhibit full transparency ... More
Quaternion Gradient and HessianJun 13 2014The optimization of real scalar functions of quaternion variables, such as the mean square error or array output power, underpins many practical applications. Solutions often require the calculation of the gradient and Hessian, however, real functions ... More
Understanding the One-Pixel Attack: Propagation Maps and Locality AnalysisFeb 08 2019Deep neural networks were shown to be vulnerable to single pixel modifications. However, the reason behind such phenomena has never been elucidated. Here, we propose Propagation Maps which show the influence of the perturbation in each layer of the network. ... More
Seltrapping in flat band lattices with nonlinear disorderOct 11 2018We study the selftrapping properties of an initially localized excitation in several flat band lattices, in the presence of nonlinear (Kerr) disorder. In the weak nonlinearity regime, the dynamics is controlled by the degeneracy of the bands leading to ... More
Low-Complexity Integer-Forcing Methods for Block Fading MIMO Multiple-Access ChannelsNov 21 2017Integer forcing is an alternative approach to conventional linear receivers for multiple-antenna systems. In an integer-forcing receiver, integer linear combinations of messages are extracted from the received matrix before each individual message is ... More
RefDiff: Detecting Refactorings in Version HistoriesApr 05 2017Refactoring is a well-known technique that is widely adopted by software engineers to improve the design and enable the evolution of a system. Knowing which refactoring operations were applied in a code change is a valuable information to understand software ... More
Universal Secure Error-Correcting Schemes for Network CodingJan 19 2010This paper considers the problem of securing a linear network coding system against an adversary that is both an eavesdropper and a jammer. The network is assumed to transport n packets from source to each receiver, and the adversary is allowed to eavesdrop ... More
Wall-crossing and recursion formulae for tropical Jucys coversMay 06 2019In recent work, the authors derived a tropical interpretation of monotone and strictly monotone double Hurwitz numbers. In this paper, we apply the technique of tropical flows to this interpretation in order to provide a new proof of the piecewise polynomiality ... More
Casimir force between $δ-δ^{\prime}$ mirrors transparent at high frequenciesJul 21 2016Nov 01 2016We investigate, in the context of a real massless scalar field in $1+1$ dimensions, models of partially reflecting mirrors simulated by Dirac $\delta-\delta^{\prime}$ point interactions. In the literature, these models do not exhibit full transparency ... More
Generating Predicate Callback Summaries for the Android FrameworkMar 27 2017Mar 29 2017One of the challenges of analyzing, testing and debugging Android apps is that the potential execution orders of callbacks are missing from the apps' source code. However, bugs, vulnerabilities and refactoring transformations have been found to be related ... More
Universal Secure Network Coding via Rank-Metric CodesSep 21 2008Apr 27 2010The problem of securing a network coding communication system against an eavesdropper adversary is considered. The network implements linear network coding to deliver n packets from source to each receiver, and the adversary can eavesdrop on \mu arbitrarily ... More
On Metrics for Error Correction in Network CodingMay 25 2008Aug 28 2009The problem of error correction in both coherent and noncoherent network coding is considered under an adversarial model. For coherent network coding, where knowledge of the network topology and network code is assumed at the source and destination nodes, ... More
Polar metals as electrodes to suppress the critical-thickness limit in ferroelectric nanocapacitorsNov 19 2016Enhancing the performance of nanoscale ferroelectric (FE) field-effect transistors and FE capacitors for memory devices and logic relies on miniaturizing the metal electrode/ferroelectric area and reducing the thickness of the insulator. Although size ... More
Riemann Hypothesis: Architecture of a conjecture "along" the lines of Pólya. From trivial zeros and Harmonic Oscillator to information about non-trivial zeros of the Riemann zeta-functionJun 16 2013Jun 20 2013We propose an architecture of a conjecture concerning the Riemann Hypothesis in the form of an "alternative" to the P\'olya strategy: we construct a Hamiltonian H_Polya whose spectrum coincides exactly with that of the Harmonic Oscillator Hamiltonian ... More
Self Organizing Classifiers: First Steps in Structured Evolutionary Machine LearningNov 20 2018Learning classifier systems (LCSs) are evolutionary machine learning algorithms, flexible enough to be applied to reinforcement, supervised and unsupervised learning problems with good performance. Recently, self organizing classifiers were proposed which ... More
Two-dimensional materials in the presence of nonplanar interfacesOct 21 2018We consider a planar two-dimensional system between two media with different dielectric constants and in the presence of a third dielectric medium separated by a nonplanar interface. Extending a perturbative method for solving Poisson's equation, developed ... More
Coded Packet Transport for Optical Packet/Burst Switched NetworksJan 26 2016This paper presents the Coded Packet Transport (CPT) scheme, a novel transport mechanism for Optical Packet/Burst Switched (OPS/OBS) networks. The CPT scheme exploits the combined benefits of source coding by erasure codes and path diversity to provide ... More