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we consider manipulation strategies for the rank - maximal matching problem. in the rank - maximal matching problem we are given a bipartite graph $ g = ( a \ cup p, e ) $ such that $ a $ denotes a set of applicants and $ p $ a set of posts. each applicant $ a \ in a $ has a preference list over the set of his neighbours in $ g $, possibly involving ties. preference lists are represented by ranks on the edges - an edge $ ( a, p ) $ has rank $ i $, denoted as $ rank ( a, p ) = i $, if post $ p $ belongs to one of $ a $ ' s $ i $ - th choices. a rank - maximal matching is one in which the maximum number of applicants is matched to their rank one posts and subject to this condition, the maximum number of applicants is matched to their rank two posts, and so on. a rank - maximal matching can be computed in $ o ( \ min ( c \ sqrt { n }, n ) m ) $ time, where $ n $ denotes the number of applicants, $ m $ the number of edges and $ c $ the maximum rank of an edge in an optimal solution. a central authority matches applicants to posts. it does so using one of the rank - maximal matchings. since there may be more than one rank - maximal matching of $ g $, we assume that the central authority chooses any one of them randomly. let $ a _ 1 $ be a manipulative applicant, who knows the preference lists of all the other applicants and wants to falsify his preference list so that he has a chance of getting better posts than if he were truthful. in the first problem addressed in this paper the manipulative applicant $ a _ 1 $ wants to ensure that he is never matched to any post worse than the most preferred among those of rank greater than one and obtainable when he is truthful. in the second problem the manipulator wants to construct such a preference list that the worst post he can become matched to by the central authority is best possible or in other words, $ a _ 1 $ wants to minimize the maximal rank of a post he can become matched to.
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arxiv:1710.11462
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let $ x $ be a real banach space with a normalized duality mapping uniformly norm - to - weak $ ^ \ star $ continuous on bounded sets or a reflexive banach space which admits a weakly continuous duality mapping $ j _ { \ phi } $ with gauge $ \ phi $. let $ f $ be an { \ em $ \ alpha $ - contraction } and $ \ { t _ n \ } $ a sequence of nonexpansive mapping, we study the strong convergence of explicit iterative schemes x _ { n + 1 } = \ alpha _ n f ( x _ n ) + ( 1 - \ alpha _ n ) t _ n x _ n with a general theorem and then recover and improve some specific cases studied in the literature
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arxiv:0712.1172
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for a newform for gamma _ 0 ( n ) of even weight k, we prove that its attached p - adic l - function is not identically zero on the group z _ p of the p - adic units. if p > 3, we prove that the order of vanishing at any p - adic integer is finite.
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arxiv:0905.4682
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the spontaneous emergence of contraction - inducing electrical activity in the uterus at the beginning of labor remains poorly understood, partly due to the seemingly contradictory observation that isolated uterine cells are not spontaneously active. it is known, however, that the expression of gap junctions increases dramatically in the approach to parturition, which results in a significant increase in inter - cellular electrical coupling. in this paper, we build upon previous studies of the activity of electrically excitable smooth muscle cells ( myocytes ) and investigate the mechanism through which the coupling of these cells to electrically passive cells results in the generation of spontaneous activity in the uterus. using a recently developed, realistic model of uterine muscle cell dynamics, we investigate a system consisting of a myocyte coupled to passive cells. we then extend our analysis to a simple two - dimensional lattice model of the tissue, with each myocyte being coupled to its neighbors, as well as to a random number of passive cells. we observe that different dynamical regimes can be observed over a range of gap junction conductances : at low coupling strength, the activity is confined to cell clusters, while the activity for high coupling may spread across the entire tissue. additionally, we find that the system supports the spontaneous generation of spiral wave activity. our results are both qualitatively and quantitatively consistent with observations from in vitro experiments. in particular, we demonstrate that an increase in inter - cellular electrical coupling, for realistic parameter values, strongly facilitates the appearance of spontaneous action potentials that may eventually lead to parturition.
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arxiv:1409.5302
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this paper presents the operator form of the effective potential v governing the time evolution in 2 and 3 and n dimensional subspace of states. the general formula for the n dimensional case is considered the starting point for the calculation of the explicit formulae for 2 and 3 dimensional degenerate and non - degenerate cases. we relate the 2 and 3 dimensional cases to some physical systems which are currently investigated.
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arxiv:hep-th/0001058
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industrial cyber - infrastructure is normally a multilayered architecture. the purpose of the layered architecture is to hide complexity and allow independent evolution of the layers. in this paper, we argue that this traditional strict layering results in poor transparency across layers affecting the ability to significantly improve resiliency. we propose a contract - based methodology where components across and within the layers of the cyber - infrastructure are associated with contracts and a light - weight resilience manager. this allows the system to detect faults ( contract violation monitored using observers ) and react ( change contracts dynamically ) effectively. it results in ( 1 ) improving transparency across layers ; helps resiliency, ( 2 ) decoupling fault - handling code from application code ; helps code maintenance, ( 3 ) systematically generate error - free fault handling code ; reduces development time. using an industrial case study, we demonstrate the proposed methodology.
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arxiv:2004.04444
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phase invariants are important pieces of information about the atomic structures of crystals. there are several mathematical methods in x - ray crystallography to estimate phase invariants. the multi - wave diffraction phenomenon offers a unique opportunity of physically measuring phase invariants. in this work, the underneath principals for developing an automatic procedure to extract accurate phase - invariant values are described. a general systematic procedure is demonstrated, in practice, by analyzing intensity data from a kdp crystal.
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arxiv:cond-mat/0409487
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given a simple graph $ g $ and an integer $ k $, the goal of $ k $ - clique problem is to decide if $ g $ contains a complete subgraph of size $ k $. we say an algorithm approximates $ k $ - clique within a factor $ g ( k ) $ if it can find a clique of size at least $ k / g ( k ) $ when $ g $ is guaranteed to have a $ k $ - clique. recently, it was shown that approximating $ k $ - clique within a constant factor is w [ 1 ] - hard [ lin21 ]. we study the approximation of $ k $ - clique under the exponential time hypothesis ( eth ). the reduction of [ lin21 ] already implies an $ n ^ { \ omega ( \ sqrt [ 6 ] { \ log k } ) } $ - time lower bound under eth. we improve this lower bound to $ n ^ { \ omega ( \ log k ) } $. using the gap - amplification technique by expander graphs, we also prove that there is no $ k ^ { o ( 1 ) } $ factor fpt - approximation algorithm for $ k $ - clique under eth. we also suggest a new way to prove the parameterized inapproximability hypothesis ( pih ) under eth. we show that if there is no $ n ^ { o ( \ frac { k } { \ log k } ) } $ algorithm to approximate $ k $ - clique within a constant factor, then pih is true.
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arxiv:2111.14033
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##tion of property rights. = = = welfare = = = welfare economics uses microeconomics techniques to evaluate well - being from allocation of productive factors as to desirability and economic efficiency within an economy, often relative to competitive general equilibrium. it analyses social welfare, however measured, in terms of economic activities of the individuals that compose the theoretical society considered. accordingly, individuals, with associated economic activities, are the basic units for aggregating to social welfare, whether of a group, a community, or a society, and there is no " social welfare " apart from the " welfare " associated with its individual units. = = macroeconomics = = macroeconomics, another branch of economics, examines the economy as a whole to explain broad aggregates and their interactions " top down ", that is, using a simplified form of general - equilibrium theory. such aggregates include national income and output, the unemployment rate, and price inflation and subaggregates like total consumption and investment spending and their components. it also studies effects of monetary policy and fiscal policy. since at least the 1960s, macroeconomics has been characterised by further integration as to micro - based modelling of sectors, including rationality of players, efficient use of market information, and imperfect competition. this has addressed a long - standing concern about inconsistent developments of the same subject. macroeconomic analysis also considers factors affecting the long - term level and growth of national income. such factors include capital accumulation, technological change and labour force growth. = = = growth = = = growth economics studies factors that explain economic growth – the increase in output per capita of a country over a long period of time. the same factors are used to explain differences in the level of output per capita between countries, in particular why some countries grow faster than others, and whether countries converge at the same rates of growth. much - studied factors include the rate of investment, population growth, and technological change. these are represented in theoretical and empirical forms ( as in the neoclassical and endogenous growth models ) and in growth accounting. = = = business cycle = = = the economics of a depression were the spur for the creation of " macroeconomics " as a separate discipline. during the great depression of the 1930s, john maynard keynes authored a book entitled the general theory of employment, interest and money outlining the key theories of keynesian economics. keynes contended that aggregate demand for goods might be insufficient during economic downturns, leading to unnecessarily high unemployment and losses of potential output. he
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https://en.wikipedia.org/wiki/Economics
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a quantal system in an eigenstate, of operators with a continuous nondegenerate eigenvalue spectrum, slowly transported round a circuit c by varing parameters in its hamiltonian, will acquire a generalized geometrical phase factor. an explicit formula for a generalized geometrical phase is derived in terms of the eigenstates of the hamiltonian. as an illustration the generalized geometrical phase is calculated for relativistic spinning particles in slowly - changing electromagnetic fields. it is shown that the the s - matrix and the usual scattering ( with negligible reflexion ) phase shift can be interpreted as a generalized geometrical phase.
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arxiv:0804.4082
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we present numerically exact continuous - time quantum monte carlo algorithm for fermions with a general non - local in space - time interaction. the new determinantal grand - canonical scheme is based on a stochastic series expansion for the partition function in the interaction representation. the method is particularly applicable for multi - band time - dependent correlations since it does not invoke the hubbard - stratonovich transformation. the test calculations for exactly solvable models as well results for the green function and for the time - dependent susceptibility of the multi - band super - symmetric model with a spin - flip interaction are discussed.
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arxiv:cond-mat/0411344
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this paper describes how it is possible to increase gp computing power via volunteer computing ( vc ) using the boinc framework. two experiments using well - known gp tools - lil - gp & ecj - are performed in order to demonstrate the benefit of using vc in terms of computing power and speed up. finally we present an extension of the model where any gp tool or framework can be used inside boinc regardless of its programming language, complexity or required operating system.
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arxiv:0801.1210
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the stability, electronic and optical properties of single - walled carbon nanotubes ( cnts ) and graphene noncovalently functionalized with free - base tetraphenylporphyrin ( tpp ) molecules is addressed by density functional theory calculations, including corrections to dispersive interactions. we study the tpp physisorption on 42 cnt species, particularly those with chiral indices ( $ n $, $ m $ ), where $ 5 \ leq n \ leq 12 $ and $ 0 \ leq m \ leq n $. our results show a quite strong $ \ pi $ - $ \ pi $ interaction between tpp and the cnt surface, with binding energies ranging from 1. 1 to 1. 8 ev, where higher energies can be associated with increasing cnt diameters. we also find that the tpp optical absorptions would not be affected by the cnt diameter or chirality. results for the tpp physisorption on graphene show a remarkable stability with binding energy of 3. 2 ev, inducing a small redshift on the $ \ pi $ - stacked tpp absorption bands. the strong graphene - tpp interaction also induces a charge transfer from tpp to graphene, indicating a $ n $ - type doping mechanism without compromising the graphene structure.
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arxiv:1506.00282
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marine stratocumulus cloud decks are regarded as the reflectors of the climate system, returning back to space a significant part of the income solar radiation, thus cooling the atmosphere. such clouds can exist in two stable modes, open and closed cells, for a wide range of environmental conditions. this emergent behavior of the system, and its sensitivity to aerosol and environmental properties, is captured by a set of nonlinear equations. here, using linear stability analysis, we express the transition from steady to a limit - cycle state analytically, showing how it depends on the model parameters. we show that the control of the droplet concentration ( n ) the environmental carrying - capacity ( h0 ) and the cloud recovery parameter ( tau ) can be linked by a single nondimensional parameter mu = n / ( alfa * tau * h0 ), suggesting that for deeper clouds the transition from open ( oscillating ) to closed ( stable fixed point ) cells will occur for higher droplet concentration ( i. e. higher aerosol loading ). the analytical calculations of the possible states, and how they are affected by changes in aerosol and the environmental variables, provide an enhanced understanding of the complex interactions of clouds and rain.
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arxiv:1609.01981
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the sea quark contribution to the nucleon spin is an important piece for a complete understanding of the nucleon spin structure. the production of $ w $ bosons in longitudinally polarized $ p + p $ collisions at rhic provides an unique probe for the sea quark polarization, through the parity - violating single - spin asymmetry, $ a _ l $. at the star experiment, $ w $ bosons can be effectively detected through the leptonic decay channel $ w \ to e \ nu $ with the electromagnetic calorimeters and time projection chamber at mid - rapidity. the previous star measurements of $ a _ l $ for $ w $ boson production from datasets taken in 2011 and 2012 have provided significant constraints on the helicity distribution functions of $ \ bar u $ and $ \ bar d $ quarks. in 2013 the star experiment collected $ p + p $ data with an integrated luminosity of about 250 pb $ ^ { - 1 } $ at $ \ sqrt s $ = 510 gev with an average beam polarization of about $ 56 \ % $, which is about three times the total integrated luminosity of previous years. the final $ a _ l $ results from the star 2013 data sample are presented and are also combined with previous 2011 + 2012 results. the comparison with theoretical expectations suggests a flavor asymmetry with $ \ delta \ bar { u } ( x ) $ $ > $ $ \ delta \ bar { d } ( x ) $ for sea quark helicity distributions with $ 0. 05 < x < 0. 25 $.
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arxiv:1901.01734
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we investigate macroscopic behavior of a dynamical network consisting of a time - evolving wiring of interactions among a group of random walkers. we assume that each walker ( agent ) has an oscillator and show that depending upon the nature of interaction, synchronization arises where each of the individual oscillators are allowed to move in such a random walk manner in a finite region of three dimensional space. here the vision range of each oscillator decides the number of oscillators with which it interacts. the live interaction between the oscillators is of intermediate type ( i. e., not local as well as not global ) and may or may not be bidirectional. we analytically derive density dependent threshold of coupling strength for synchronization using linear stability analysis and numerically verify the obtained analytical results. additionally, we explore the concept of basin stability, a nonlinear measure based on volumes of basin of attractions, to investigate how stable the synchronous state is under large perturbations. the synchronization phenomenon is analyzed taking limit cycle and chaotic oscillators for wide ranges of parameters like interaction strength k between the walkers, speed of movement v and vision range r.
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arxiv:1707.01263
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this paper introduces an innovative application of foundation models, enabling unmanned ground vehicles ( ugvs ) equipped with an rgb - d camera to navigate to designated destinations based on human language instructions. unlike learning - based methods, this approach does not require prior training but instead leverages existing foundation models, thus facilitating generalization to novel environments. upon receiving human language instructions, these are transformed into a ' cognitive route description ' using a large language model ( llm ) - a detailed navigation route expressed in human language. the vehicle then decomposes this description into landmarks and navigation maneuvers. the vehicle also determines elevation costs and identifies navigability levels of different regions through a terrain segmentation model, ganav, trained on open datasets. semantic elevation costs, which take both elevation and navigability levels into account, are estimated and provided to the model predictive path integral ( mppi ) planner, responsible for local path planning. concurrently, the vehicle searches for target landmarks using foundation models, including yolo - world and efficientvit - sam. ultimately, the vehicle executes the navigation commands to reach the designated destination, the final landmark. our experiments demonstrate that this application successfully guides ugvs to their destinations following human language instructions in novel environments, such as unfamiliar terrain or urban settings.
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arxiv:2410.10577
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seismocardiography ( scg ) has gained significant attention due to its potential applications in monitoring cardiac health and diagnosing cardiovascular conditions. conventional scg methods rely on accelerometers attached to the chest, which can be uncomfortable or inconvenient. in recent years, researchers have explored non - contact methods to capture scg signals, and one promising approach involves analyzing video recordings of the chest. in this study, we investigate a vision - based method based on the gunnar - farneback optical flow to extract scg signals from the chest skin movements recorded by a smartphone camera. we compared the scg signals extracted from the chest videos of four healthy subjects with those obtained from accelerometers and our previous method based on sticker tracking. our results demonstrated that the vision - based scg signals extracted by the proposed method closely resembled those from accelerometers and stickers, although these signals were captured from slightly different locations. the mean squared error between the vision - based scg signals and accelerometer - based signals was found to be within a reasonable range, especially between signals on head - to - foot direction ( 0. 2 $ < $ mse $ < $ 1. 5 ). additionally, heart rates derived from the vision - based scg exhibited good agreement with the gold - standard ecg measurements, with a mean difference of 0. 8 bpm. these results indicate the potential of this non - invasive method in health monitoring and diagnostics.
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arxiv:2408.09512
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in the quark model, hadrons are dominantly bound states of quark - antiquark pairs ( mesons ) or three quarks ( baryons ), but qcd also allows hadronic states to be composed of more quarks bound together. recently, besiii, belle and lhcb have confirmed the existence of four - quark and pentaquark candidates. these new states, along with experimentally observed resonances that do not fit well into the charmonium and bottomonium spectra, present challenges and opportunities for strong interaction theory. in this talk, i will review results on charmonium - like exotic quark states that have been observed by the besiii experiment at the beijing electron positron collider ii ( bepcii ).
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arxiv:1510.01239
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the probability distribution of stock price changes is studied by analyzing a database ( the trades and quotes database ) documenting every trade for all stocks in three major us stock markets, for the two year period jan 1994 - - dec 1995. a sample of 40 million data points is extracted, which is substantially larger than studied hitherto. we find an asymptotic power - law behavior for the cumulative distribution with an exponent alpha approximately 3, well outside the levy regime 0 < alpha < 2.
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arxiv:cond-mat/9803374
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the synchrosqueezing method aims at decomposing 1d functions as superpositions of a small number of " intrinsic modes ", supposed to be well separated both in time and frequency. based on the unidimensional wavelet transform and its reconstruction properties, the synchrosqueezing transform provides a powerful representation of multicomponent signals in the time - frequency plane, together with a reconstruction of each mode. in this paper, a bidimensional version of the synchrosqueezing transform is defined, by considering a well - adapted extension of the concept of analytic signal to images : the monogenic signal. the natural bidimensional counterpart of the notion of intrinsic mode is then the concept of " intrinsic monogenic mode " that we define. thereafter, we investigate the properties of its associated monogenic wavelet decomposition. this leads to a natural bivariate extension of the synchrosqueezed wavelet transform, for decomposing and processing multicomponent images. numerical tests validate the effectiveness of the method for different examples.
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arxiv:1211.5082
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we consider a bilayer system of two - dimensional bose - einstein - condensed dipolar dark excitons ( upper layer ) and bright ones ( bottom layer ). we demonstrate that the interlayer interaction leads to a mixing between excitations from different layers. this mixing leads to the appearance of a second spectral branch in the spectrum of bright condensate. the excitation spectrum of the condensate of dark dipolar excitons then becomes optically accessible during luminescence spectra measurements of the bright condensate, which allows one to probe its kinetic properties. this approach is relevant for experimental setups, where detection via conventional techniques remains challenging ; in particular, the suggested method is useful for studying dark dipolar excitons in transition metal dichalcogenide monolayers.
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arxiv:1811.08802
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a wide range of mechanisms have been proposed to supply the energy for gamma - ray bursts ( grb ) at cosmological distances. it is a common misconception that some of these, notably ns - ns mergers, cannot meet the energy requirements suggested by recent observations. we show here that grb energies, even at the most distant redshifts detected, are compatible with current binary merger or collapse scenarios involving compact objects. this is especially so if, as expected, there is a moderate amount of beaming, since current observations constrain the energy per solid angle much more strongly and directly than the total energy. all plausible progenitors, ranging from ns - ns mergers to various hypernova - like scenarios, eventually lead to the formation of a black hole with a debris torus around it, so that the extractable energy is of the same order, 1e + 54 ergs, in all cases. mhd conversion of gravitational into kinetic and radiation energy can significantly increase the probability of observing large photon fluxes, although significant collimation may achieve the same effect with neutrino annihilation in short bursts. the lifetime of the debris torus is dictated by a variety of physical processes, such as viscous accretion and various instabilities ; these mechanisms dominate at different stages in the evolution of the torus and provide for a range of gamma - ray burst lifetimes.
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arxiv:astro-ph/9808106
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in this paper we prove some results about k3 surfaces with picard number 1 and 2. in particular, we give a new simple proof of a theorem due to oguiso which shows that, given an integer $ n $, there is a k3 surface with picard number 2 and at least $ n $ non - isomorphic fm - partners. we describe also the mukai vectors of the moduli spaces associated to the fourier - mukai partners of k3 surfaces with picard number 1.
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arxiv:math/0205126
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we propose to use nonparametric bernstein copulas as bivariate pair - copulas in high - dimensional vine models. the resulting smooth and nonparametric vine copulas completely obviate the error - prone need for choosing the pair - copulas from parametric copula families. by means of a simulation study and an empirical analysis of financial market data, we show that our proposed smooth nonparametric vine copula model is superior to competing parametric vine models calibrated via akaike ' s information criterion.
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arxiv:1210.2043
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we estimate the energy distribution of positrons produced in the interaction of ultra - relativistic electrons with a high - intensity laser beam. the underlying trident process is factorized on the probabilistic level. that is, we deploy a two - step mechanism for the formation of electron - positron pairs. in the first step, a high - energy photon is produced as a result of nonlinear compton scattering. in the second step, an electron - positron pair is created by the nonlinear ( multi - photon ) breit - wheeler process.
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arxiv:2108.13043
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deep neural networks ( dnns ) are shown to be promising solutions in many challenging artificial intelligence tasks. however, it is very hard to figure out whether the low precision of a dnn model is an inevitable result, or caused by defects. this paper aims at addressing this challenging problem. we find that the internal data flow footprints of a dnn model can provide insights to locate the root cause effectively. we develop deepmorph ( dnn tomography ) to analyze the root cause, which can guide a dnn developer to improve the model.
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arxiv:1909.02190
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we analyze far - ultraviolet spectra and ancillary data of the super star cluster ssc - n and its surrounding h ii region in the nearby dwarf galaxy ii zw 40. from the ultraviolet spectrum, we derive a low internal reddening of e ( b - v ) = 0. 07 + / - 0. 03, a mass of ( 9. 1 + / - 1. 0 ) x 10 ^ 5 lsol, a bolometric luminosity of ( 1. 1 + / - 0. 1 ) x 10 ^ 9 lsol, a number of ionizing photons of ( 6 + / - 2 ) x 10 ^ 52 s ^ - 1, and an age of ( 2. 8 + / - 0. 1 ) myr. these parameters agree with the values derived from optical and radio data, indicating no significant obscured star formation, absorption of photons by dust, or photon leakage. ssc - n and its nebulosity are an order of magnitude more massive and luminous than 30 doradus and its ionizing cluster. photoionization modeling suggests a high ionization parameter and a c / o ratio where c is between primary and secondary. we calculate diagnostic emission - line ratios and compare ssc - n to local star - forming galaxies. the ssc - n nebula does not coincide with the locus defined by local galaxies. rather, it coincides with the location of " green pea " galaxies, objects which are often considered nearby analogs of the galaxies reionizing the universe. most stellar features are well - reproduced by synthetic spectra. however, the ssc - n cluster has strong, broad, stellar he ii 1640 emission that cannot be reproduced, suggesting a deficit of he - enhanced stars with massive winds in the models. we discuss possible sources for the broad he ii emission, including very massive stars and / or enhanced mixing processes.
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arxiv:1808.04332
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podcast episodes often contain material extraneous to the main content, such as advertisements, interleaved within the audio and the written descriptions. we present classifiers that leverage both textual and listening patterns in order to detect such content in podcast descriptions and audio transcripts. we demonstrate that our models are effective by evaluating them on the downstream task of podcast summarization and show that we can substantively improve rouge scores and reduce the extraneous content generated in the summaries.
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arxiv:2103.02585
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in this paper, a new concept, radial coverage strength, is first proposed to characterize the visual sensing performance when the orientation of the target pose is considered. in particular, the elevation angle of the optical pose of the visual sensor is taken to decompose the visual coverage strength into effective and ineffective components, motivated by the imaging intuition. an optimization problem is then formulated for a multi - camera network to maximize the coverage of the object area based on the strength information fusion along the effective coverage strength direction through the deployment of the angle between radial coverage vector of the camera optical pose. both simulation and experiments are conducted to validate the proposed approach and comparison with existing methods is also provided.
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arxiv:2004.00787
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irreducibility of the set of quantum field operators has been proved in noncommutative quantum field theory in the general case when time does not commute with spatial variables.
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arxiv:1209.0206
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we present spintronic devices based hardware implementation of unet for segmentation tasks. our approach involves designing hardware for convolution, deconvolution, rectified activation function ( relu ), and max pooling layers of the unet architecture. we designed the convolution and deconvolution layers of the network using the synaptic behavior of the domain wall mtj. we also construct the relu and max pooling functions of the network utilizing the spin hall driven orthogonal current injected mtj. to incorporate the diverse physics of spin - transport, magnetization dynamics, and cmos elements in our unet design, we employ a hybrid simulation setup that couples micromagnetic simulation, non - equilibrium green ' s function, spice simulation along with network implementation. we evaluate our unet design on the camvid dataset and achieve segmentation accuracies of 83. 71 $ \ % $ on test data, on par with the software implementation with 821mj of energy consumption for on - chip training over 150 epochs. we further demonstrate nearly one order $ ( 10 \ times ) $ improvement in the energy requirement of the network using unstable ferromagnet ( $ \ delta $ = 4. 58 ) over the stable ferromagnet ( $ \ delta $ = 45 ) based relu and max pooling functions while maintaining the similar accuracy. the hybrid architecture comprising domain wall mtj and unstable fm - based mtj leads to an on - chip energy consumption of 85. 79mj during training, with a testing energy cost of 1. 55 $ \ mu j $.
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arxiv:2403.02863
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we present a real - time multivariate anomaly detection algorithm for data streams based on the probabilistic exponentially weighted moving average ( pewma ). our formulation is resilient to ( abrupt transient, abrupt distributional, and gradual distributional ) shifts in the data. the novel anomaly detection routines utilize an incremental online algorithm to handle streams. furthermore, our proposed anomaly detection algorithm works in an unsupervised manner eliminating the need for labeled examples. our algorithm performs well and is resilient in the face of concept drifts.
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arxiv:2209.12398
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we explore as clearly as possible the features of neutrino oscillation which are relevant for measurements of the cp violating kobayashi - maskawa phase delta and the sign of \ delta m ^ 2 _ { 13 }. we focus on the so called low - energy option and discuss principles for optimizing experimental parameters to measure these two quantities simultaneously. toward the goal, we first formulate a method for obtaining a bird - eye view of the phenomenon of neutrino oscillation by introducing a new powerful tool called the ` ` cp trajectory diagram in bi - probability space ' '. it allows us to represent pictorially the three effects separately in a single diagram ; effect from genuine cp violation due to the sin delta term, effect from the cp conserving cos delta term, and the fake cp violating effect due to earth matter. by using the cp trajectory diagram we observe that there is a two - fold ambiguity in the determination of delta which is related with the sign of delta m ^ 2 _ { 13 }. we then address the question of what are the promising options for conceptual design of experiments at low energies which looks for cp violation and at the same time would resolve the two - fold ambiguity. we point out that a version with distance of about 700 km, with a megaton class water cherenkov detector gives an optimal design which allows simultaneous determination of delta and the sign of delta m ^ 2 _ { 13 } { \ it in situ }. we also point out that there is a possibility that the similar { \ it in situ } measurement of both quantities can be done at the phase ii of jhf experiment with much shorter baseline, under the assumption of nature ' s kind setting of delta to the region of sin { delta } \ cdot delta m ^ 2 _ { 13 } < 0. a technique of running at high ( sim 1 gev ) and low ( sim 0. 5 gev ) beam energies is proposed as a method for better identification of delta.
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arxiv:hep-ph/0108085
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we study the standing periodic waves in the semi - discrete integrable system modelled by the ablowitz - ladik equation. we have related the stability spectrum to the lax spectrum by separating the variables and by finding the characteristic polynomial for the standing periodic waves. we have also obtained rogue waves on the background of the modulationally unstable standing periodic waves by using the end points of spectral bands and the corresponding eigenfunctions. the magnification factors for the rogue waves have been computed analytically and compared with their continuous counterparts. the main novelty of this work is that we explore a non - standard linear lax system, which is different from the standard lax representation of the ablowitz - ladik equation.
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arxiv:2303.17052
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we report an experiment to generate maximally entangled states of d - dimensional quantum systems, qudits, by using transverse spatial correlations of two parametric down - converted photons. apertures with d - slits in the arms of the twin fotons define the qudit space. by manipulating the pump beam correctly the twin photons will pass only by symmetrically opposite slits, generating entangled states between these differents paths. experimental results for qudits with d = 4 and d = 8 are shown. we demonstrate that the generated states are entangled states.
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arxiv:quant-ph/0411054
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scattered ovi 6825 \ aa \ line during the outburst, is consistent with the ionisation structure of hot components in symbiotic stars during active phases.
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arxiv:1705.00076
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electroweak production of single top quarks is an as - yet - unverified prediction of the standard model, potentially sensitive to new physics. two of the single top quark productions channels have significant charge asymmetries at the lhc, while the much larger background from $ t \ bar { t } $ is nearly charge - symmetric. this can be used to reduce systematic uncertainties and make precision measurements of single top quark production.
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arxiv:hep-ph/0503110
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the main topic of long - term researches by g. a. shajn is the nature of diffuse matter, its distribu - tion in the galaxy and extragalactic systems, interaction with the interstellar medium and hot stars, the formation of emission and reflection nebulae and stars have become the main theme of researches by shajn during some years. based on the analysis of experimental data, mainly pho - tographic observations of nebulae in the milky way and extragalactic systems, he made conclu - sions and suggested well - founded hypotheses on a wide range of the considered problems, in - cluding those related to cosmogony. the structure of nebulae, their masses and sizes give a reason to the conclusion that most of them are formed not in the process of ejection of matter from the stars, but this is the objects, which are born and evolved, and quite often comprised in giant conglomerates of gas, dust and stars. the distribution of o - stars and nebulae in spiral branches points to their genetic relation and the fundamental role of the interstellar medium as a source of their formation. the structural features of nebulae are determined by the action of magnetohydrodynamic forces. magnetic fields in a galaxy control the motion of diffuse gas - dust matter and ensure the maintenance of its spiral structure. these ideas continue being developed in modern directions of astrophysics.
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arxiv:1804.08690
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we show that any infinite collection $ ( \ gamma _ n ) _ { n \ in \ mathbb n } $ of icc, hyperbolic, property ( t ) groups satisfies the following von neumann algebraic \ emph { infinite product rigidity } phenomenon. if $ \ lambda $ is an arbitrary group such that $ l ( \ oplus _ { n \ in \ mathbb n } \ gamma _ n ) \ cong l ( \ lambda ) $ then there exists an infinite direct sum decomposition $ \ lambda = ( \ oplus _ { n \ in \ mathbb n } \ lambda _ n ) \ oplus a $ with $ a $ icc amenable such that, for all $ n \ in \ mathbb n $, up to amplifications, we have $ l ( \ gamma _ n ) \ cong l ( \ lambda _ n ) $ and $ l ( \ oplus _ { k \ geq n } \ gamma _ k ) \ cong l ( ( \ oplus _ { k \ geq n } \ lambda _ k ) \ oplus a ) $. the result is sharp and complements the previous finite product rigidity property found in [ cdss16 ]. using this we provide an uncountable family of restricted wreath products $ \ gamma \ cong \ sigma \ wr \ delta $ of icc, property ( t ) groups $ \ sigma $, $ \ delta $ whose wreath product structure is recognizable, up to a normal amenable subgroup, from their von neumann algebras $ l ( \ gamma ) $. along the way we highlight several applications of these results to the study of rigidity in the $ \ mathbb c ^ * $ - algebra setting.
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arxiv:1804.04558
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with more than 80 transits observed in the corot light curve with a cadence of 32 s, corot - exo - 2b provides an excellent case to search for the secondary eclipse of the planet, with an expected signal of less than 10 ^ - 4 in relative flux. the activity of the star causes a modulation on the flux that makes the detection of this signal challenging. we describe the technique used to seek for the secondary eclipse, that leads to a tentative 2. 5 sigma detection of a 5. 5x10 ^ - 5 eclipse. if the effect of the spots are not taken into account, the times of transit centers will also be affected. they could lead to an erroneous detection of periodic transit timing variations of ~ 20 s and with a 7. 45 d period. by measuring the transit central times at different depths of the transit ( transit bisectors ), we show that there are no such periodic variations in the corot - exo - 2b o - c residuals larger than ~ 10 s.
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arxiv:0807.4828
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prompting - based large language models ( llms ) are surprisingly powerful at generating natural language reasoning steps or chains - of - thoughts ( cot ) for multi - step question answering ( qa ). they struggle, however, when the necessary knowledge is either unavailable to the llm or not up - to - date within its parameters. while using the question to retrieve relevant text from an external knowledge source helps llms, we observe that this one - step retrieve - and - read approach is insufficient for multi - step qa. here, \ textit { what to retrieve } depends on \ textit { what has already been derived }, which in turn may depend on \ textit { what was previously retrieved }. to address this, we propose ircot, a new approach for multi - step qa that interleaves retrieval with steps ( sentences ) in a cot, guiding the retrieval with cot and in turn using retrieved results to improve cot. using ircot with gpt3 substantially improves retrieval ( up to 21 points ) as well as downstream qa ( up to 15 points ) on four datasets : hotpotqa, 2wikimultihopqa, musique, and iirc. we observe similar substantial gains in out - of - distribution ( ood ) settings as well as with much smaller models such as flan - t5 - large without additional training. ircot reduces model hallucination, resulting in factually more accurate cot reasoning. code, data, and prompts are available at \ url { https : / / github. com / stonybrooknlp / ircot }
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arxiv:2212.10509
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state - of - the - art nlp models can adopt shallow heuristics that limit their generalization capability ( mccoy et al., 2019 ). such heuristics include lexical overlap with the training set in named - entity recognition ( taill \ ' e et al., 2020 ) and event or type heuristics in relation extraction ( rosenman et al., 2020 ). in the more realistic end - to - end re setting, we can expect yet another heuristic : the mere retention of training relation triples. in this paper, we propose several experiments confirming that retention of known facts is a key factor of performance on standard benchmarks. furthermore, one experiment suggests that a pipeline model able to use intermediate type representations is less prone to over - rely on retention.
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arxiv:2109.12008
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let $ x $ and $ y $ be compact hausdorff spaces, $ e $ and $ f $ be real or complex banach spaces, and $ a ( x, e ) $ be a subspace of $ c ( x, e ) $. in this paper we study linear operators $ s, t : a ( x, e ) \ lo c ( y, f ) $ which are jointly separating, in the sense that $ \ coz ( f ) \ cap \ coz ( g ) = \ emptyset $ implies that $ \ coz ( tf ) \ cap \ coz ( sg ) = \ emptyset $. here $ \ coz ( \ cdot ) $ denotes the cozero set of a function. we characterize the general form of such maps between certain class of vector - valued ( as well as scalar - valued ) spaces of continuous functions including spaces of vector - valued lipschitz functions, absolutely continuous functions and continuously differentiable functions. the results can be applied for a pair $ t : a ( x ) \ lo a ( x ) $ and $ s : a ( x, e ) \ lo a ( x, e ) $ of linear operators, where $ a ( x ) $ is a regular banach function algebra on $ x $, such that $ f \ cdot g = 0 $ implies $ tf \ cdot sg = 0 $, for $ f \ in a ( x ) $ and $ g \ in a ( x, e ) $. if $ t $ and $ s $ are jointly separating bijections between banach algebras of scalar - valued functions of this class, then they induce a homeomorphism between $ x $ and $ y $ and, furthermore, $ t ^ { - 1 } $ and $ s ^ { - 1 } $ are also jointly separating maps.
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arxiv:1804.10915
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continuous photoplethysmography ( ppg ) - based blood pressure monitoring is necessary for healthcare and fitness applications. in artificial intelligence ( ai ), signal classification levels with the machine and deep learning arrangements need to be explored further. techniques based on time - frequency spectra, such as short - time fourier transform ( stft ), have been used to address the challenges of motion artifact correction. therefore, the proposed study works with ppg signals of more than 200 patients ( 650 + signal samples ) with hypertension, using stft with various neural networks ( convolution neural network ( cnn ), long short - term memory ( lstm ), bidirectional long short - term memory ( bi - lstm ), followed by machine learning classifiers, such as, support vector machine ( svm ) and random forest ( rf ). the classification has been done for two categories : prehypertension ( normal levels ) and hypertension ( includes stage i and stage ii ). various performance metrics have been obtained with two batch sizes of 3 and 16 for the fusion of the neural networks. with precision and specificity of 100 % and recall of 82. 1 %, the lstm model provides the best results among all combinations of neural networks. however, the maximum accuracy of 71. 9 % is achieved by the lstm - cnn model. further stacked ensemble method has been used to achieve 100 % accuracy for meta - lstm - rf, meta - lstm - cnn - rf and meta - stft - cnn - svm.
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arxiv:2405.14556
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we derive a fully discrete inverse scattering transform as a method for solving the initial - value problem for the q3 $ _ \ delta $ lattice ( difference - difference ) equation for real - valued solutions. the initial condition is given on an infinite staircase within an n - dimensional lattice and must obey a given summability condition. the forward scattering problem is one - dimensional and the solution to q3 $ _ \ delta $ is expressed through the solution of a singular integral equation. the solutions obtained depend on n discrete independent variables and n parameters.
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arxiv:1210.1869
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the lithium abundance in 62 halo dwarfs is determined from accurate equivalent widths reported in the literature and an improved infrared flux method ( irfm ) temperature scale. the li abundance of 41 plateau stars ( those with teff > 6000 k ) is found to be independent of temperature and metallicity, with a star - to - star scatter of only 0. 06 dex over a broad range of temperatures ( 6000 k < teff < 6800 k ) and metallicities ( - 3. 4 < [ fe / h ] < - 1 ), thus imposing stringent constraints on depletion by mixing and production by galactic chemical evolution. we find a mean li plateau abundance of a ( li ) = 2. 37 dex ( 7li / h = 2. 34 x 10 ^ { - 10 } ), which, considering errors of the order of 0. 1 dex in the absolute abundance scale, is just in borderline agreement with the constraints imposed by the theory of primordial nucleosynthesis and wmap data ( 2. 51 < a ( li ) [ wmap ] < 2. 66 dex ).
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arxiv:astro-ph/0409383
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quantum networks have the potential to transform secure communication via quantum key distribution and enable novel concepts in distributed quantum computing and sensing. coherent quantum light generation at telecom wavelengths is fundamental for fibre - based network implementations, but fourier - limited emission and subnatural linewidth photons have so far only been reported from systems operating in the visible to near - infrared wavelength range. here, we use inas / inp quantum dots to demonstrate photons with coherence times much longer than the fourier limit at telecom wavelength. evidence of the responsible elastic laser scattering mechanism is observed in a distinct signature in two - photon interference measurements, and is confirmed using a direct measurement of the emission coherence. further, we show that even the inelastically scattered photons have coherence times within the error bars of the fourier limit. finally, we make direct use of the minimal attenuation in fibre for these photons by measuring two - photon interference after 25 km of fibre, thereby demonstrating indistinguishability of photons emitted about 100 000 excitation cycles apart.
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arxiv:2205.07997
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a general model - based extended state observer ( gmb - eso ) is proposed for single - input single - output linear time - invariant systems with a given state space model, where the total disturbance, a lump sum of model uncertainties and external disturbances, is defined as an extended state in the same manner as in the original formulation of eso. the conditions for the existence of such an observer, however, are shown for the first time as 1 ) the original plant is observable ; and 2 ) there is no invariant zero between the plant output and the total disturbance. then, the finite - step convergence and error characteristics of gmb - eso are shown by exploiting its inherent connection to the well - known unknown input observer ( uio ). furthermore, it is shown that, with the relative degree of the plant greater than one and the observer eigenvalues all placed at the origin, gmb - eso produces the identical disturbance estimation as that of uio. finally, an improved gmb - eso with built - in zero dynamics is proposed for those plants with zero dynamics, which is a problem that has not been addressed in all existing eso designs.
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arxiv:2208.12314
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a theoretical understanding of the experimental electronic transport phenomena in gas sensors based on dna functionalized graphene is presented by quantitatively investigating the time - dependent electronic transport in these devices using the nonequilibrium green ' s function ( negf ) formalism and tight - binding approximation. the time - dependent zeroth and first order contributions to the current are calculated with derivations of the equation of motion and dyson equation. the zeroth order contribution is identified as the time - dependent landauer formula in terms of the slow time variable and the first order contribution is found to be small in this experiment. the current is explicitly calculated by deriving a formula for the transmission function and considering a form for the hopping integral which includes the effect of chemical vapors on the charge distribution of the carbon atoms and the nearest - neighbor carbon - carbon distance $ \ rm a _ { cc } $. theoretical results are found in agreement with the experimental results. a shift in the fermi level ( $ \ rm \ varepsilon _ f $ ) is calculated, which is a result of shift in the dirac point due to adsorption of vapors on the dna functionalized graphene. the work suggests that using the same values of change in $ \ rm a _ { cc } $ due to the four dna bases for a specific target vapor, the theoretical values of the current response can be predicted for different dna sequences leading to the application of the graphene sensors as a dna analyser.
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arxiv:1309.3373
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the well - known 5 - parameter isometry group of plane gravitational waves in $ 4 $ dimensions is identified as levy - leblond ' s carroll group in $ 2 + 1 $ dimensions with no rotations. our clue is that plane waves are bargmann spaces into which carroll manifolds can be embedded. we also comment on the scattering of light by a gravitational wave and calculate its electric permittivity considered as an impedance - matched metamaterial.
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arxiv:1702.08284
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miriad is a radio interferometry data - reduction package, designed for taking raw data through to the image analysis stage. the miriad project, begun in 1988, is now middle - aged. with the wisdom of hindsight, we review design decisions and some of miriad ' s characteristics.
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arxiv:astro-ph/0612759
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in this paper, we present a general theory of aperiodic subwavelength arrays for controlling electromagnetic waves. the considered platform is formed by an array of electrically small loaded scatterers above a ground plane. while the array is geometrically periodic, all the loads can be in general different, so that the distributions of currents induced by plane waves are not periodic. to allow analytical solutions, we study arrays of thin wires or strips loaded by bulk loads. we demonstrate a practical way of creating tunable and reconfigurable multifunctional devices, on examples of superdirective beam splitters, focusing lenses establishing subdiffraction focusing, and absorbers going beyond perfect absorption. contrary to the constraints imposed by the floquet theorem in periodic counterparts like periodic metasurfaces or metagratings, where a fixed angle of incidence and period dictate the propagating directions of reflected waves, the proposed aperiodic designs allow controlling all propagating modes in any direction, which provides more freedom in manipulating electromagnetic waves. we hope that these results can be useful in multiple applications, such as telecommunications, radar techniques, signal processing, and energy harnessing.
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arxiv:2404.07608
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we investigated the statistical distributions of physical quantities of solar flares and associated coronal mass ejections ( cmes ). we found that the distributions of the x - ray peak fluxes of cme - related flares, their time intervals, and speeds of associated cmes are in good agreement with log - normal distributions. one possible interpretation of this is that only large energetic mass ejections can escape from the solar corona, which become cmes in the interplanetary space. this ` ` filtering effect ' ' may be the reason why statistical distributions of some physical quantities are similar to log - normal distribution. it is known that the distributions of several physical quantities of gamma - ray bursts ( grbs ) are also log - normal distributions, and that the time variations of gamma - ray intensity in grbs are very similar to those of hard x - rays of solar flares. on the basis of these similarities and physical consideration of magnetohydrodynamic properties of an accretion disk around a black hole, which is supposed to be situated in the central engine of a grb, we propose a new model of the central engine of grbs, the { \ it flare / cme model }, in which grbs are formed by nonsteady jets consisting of intermittent ejections of mass ( like solar cmes ) associated with reconnection events ( like solar flares ) in the accretion disk corona. such nonsteady mhd jets would produce many shocks as well as local reconnection events far from the central engine. in this model, only large energetic mass ejections can escape from the accretion disk corona, so that statistical distributions of some physical quantities are similar to log - normal distributions.
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arxiv:astro-ph/0401352
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we present a model of pressure effects of a two - band superconductor based on a ginzburg - landau free energy with two order parameters. the parameters of the theory are pressure as well as temperature dependent. new pressure effects emerge as a result of the competition between the two bands. the theory then is applied to mgb2. we identify two possible scenaria regarding the fate of the two $ \ sigma $ subbands under pressure, depending on whether or not both subbands are above the fermi energy at ambient pressure. the splitting of the two subbands is probably caused by the e2g distortion. if only one subband is above the fermi energy at ambient pressure ( scenario i ), application of pressure diminishes the splitting and it is possible that the lower subband participates in the superconductivity. the corresponding crossover pressure and gruneisen parameter are estimated. in the second scenario both bands start above the fermi energy and they move below it, either by pressure or via the substitution of mg by al. in both scenaria, the possibility of electronical topological transition is emphasized. experimental signatures of both scenaria are presented and existing experiments are discussed in the light of the different physical pictures.
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arxiv:cond-mat/0301491
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we report on the magnetic and structural properties of ferromagnetic - insulating la $ _ 2 $ comno $ _ 6 $ thin films grown on top of ( 001 ) sto substrates by means of rf sputtering technique. careful structural analysis, by using synchrotron x - ray diffraction, allows identifying two different crystallographic orientations that are closely related to oxygen stoichiometry and to the features ( coercive fields and remanence ) of the hysteresis loops. both curie temperature and magnetic hysteresis turn out to be dependent on the oxygen stoichiometry. in situ annealing conditions allow tailoring the oxygen content of the films, therefore controlling their microstructure and magnetic properties.
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arxiv:1407.2072
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previous surveys in a few metal - poor globular clusters ( gcs ) showed that the determination of abundances for li and proton - capture elements offers a key tool to address the intracluster pollution scenario. in this letter, we present na, o, and li abundances in a large sample of dwarf stars in the metal - rich gc 47 tucanae. we found a clear na - o anticorrelation, in good agreement with what obtained for giant members by carretta et al. while lithium and oxygen abundances appear to be positively correlated with each other, there is a large scatter, well exceeding observational errors, and no anticorrelation with sodium. these findings suggest that li depletion, due to mechanisms internal to the stars ( which are cooler and more metal - rich than those on the spite plateau ), combines with the usual pollution scenario responsible for the na - o anticorrelation.
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arxiv:1003.0013
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in this paper, we present a stochastic method for the simulation of laplace ' s equation with a mixed boundary condition in planar domains that are polygonal or bounded by circular arcs. we call this method the reflected walk - on - spheres algorithm. the method combines a traditional walk - on - spheres algorithm with use of reflections at the neumann boundaries. we apply our algorithm to simulate numerical conformal mappings from certain quadrilaterals to the corresponding canonical domains, and to compute their conformal moduli. finally, we give examples of the method on three dimensional polyhedral domains, and use it to simulate the heat flow on an l - shaped insulated polyhedron.
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arxiv:2312.15382
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robotic surface consisting of many actuators can change shape to perform tasks, such as facilitating human - machine interactions and transporting objects. increasing the number of actuators can enhance the robot ' s capacity, but controlling them requires communication bandwidth to increase equally in order to avoid time delays. we propose a novel control method that has constant time delays no matter how many actuators are in the robot. having a distributed nature, the method first approximates target shapes, then broadcasts the approximation coefficients to the actuators, and relies on themselves to compute the inputs. we build a robotic pin array and measure the time delay as a function of the number of actuators to confirm the system size - independent scaling behavior. the shape - changing ability is achieved based on function approximation algorithms, i. e. discrete cosine transform or matching pursuit. we perform experiments to approximate target shapes and make quantitative comparison with those obtained from standard sequential control method. a good agreement between the experiments and theoretical predictions is achieved, and our method is more efficient in the sense that it requires less control messages to generate shapes with the same accuracy. our method is also capable of dynamic tasks such as object manipulation.
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arxiv:2412.00492
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motion trajectories offer reliable references for physics - based motion learning but suffer from sparsity, particularly in regions that lack sufficient data coverage. to address this challenge, we introduce a self - supervised, structured representation and generation method that extracts spatial - temporal relationships in periodic or quasi - periodic motions. the motion dynamics in a continuously parameterized latent space enable our method to enhance the interpolation and generalization capabilities of motion learning algorithms. the motion learning controller, informed by the motion parameterization, operates online tracking of a wide range of motions, including targets unseen during training. with a fallback mechanism, the controller dynamically adapts its tracking strategy and automatically resorts to safe action execution when a potentially risky target is proposed. by leveraging the identified spatial - temporal structure, our work opens new possibilities for future advancements in general motion representation and learning algorithms.
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arxiv:2402.13820
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surface spin waves in the short - wavelength regime enable ultrafast, nanoscale magnon - based devices. here we report the emergence of surface spin - wave excitations within the bulk magnon band gap of type - a van der waals antiferromagnets composed of antiferromagnetically coupled ferromagnetic monolayers. in contrast to the magnetostatic damon - eshbach modes in magnetic slabs, these surface waves are pure exchange modes owing to the reduced interlayer exchange coupling at surface layers, and thus persist in ultrathin multilayer stacks and at large wave numbers. we show that they can be efficiently excited by electromagnetic waves, with absorption power comparable to or even exceeding that of bulk modes. moreover, their magnetic stray fields exhibit pronounced even - odd oscillations with the number of monolayers that should be observable by nv - center magnetometry.
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arxiv:2504.21465
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i report on progress in the calculation of one - loop amplitudes with a space - like gluon. amplitudes with space - like partons are relevant for factorization procedure s that require initial - state partons with non - vanishing transverse momentum components.
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arxiv:1807.05930
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the polycrystalline sm2mgmno6 ( smmo ) was synthesized at 1173k by means of sol - gel technique. rietveld refine - ment of x - ray diffraction ( xrd ) pattern confirmed the formation of a single phase monoclinic structure with space group p21 / n. the band gap achieved from uv - vis spectra shows the semiconducting nature of the material. to observe the effect of grains and grain - boundaries in the conduction process and dielectric relaxation measurements are carried out on smmo sample at different frequencies between 313 k and 673 k. an electrical equivalent circuit consisting of the resistance and constant phase element is used to clarify the impedance data.
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arxiv:1706.10038
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the copper fluoride $ cu _ 2f _ 5 $ is a proposed stable compound that can be seen as a layered lattice of $ s = 1 $ and $ s = 1 / 2 $ sites, corresponding to copper ions. intending to cast light on the transport properties of ferrimagnetic magnons, we use the linear spin wave approach to study the magnon band structure of the 2d lattice in a ferrimagnetic off - plane order, as well as the transverse transport of magnons in the crystal bulk. a magnetic field or temperature gradient can induce transverse ( hall - like ) transport within the linear response theory generated by the berry curvature of the eigenstates. as in most cases involving magnons, the berry curvature is related to dzyaloshinskii - moriya interactions between next - near - neighbors. the band structure of the system is non - degenerate and the transport coefficients are non - null. the novel and interesting feature of the system is that, within certain conditions, the transport coefficients versus temperature curves are non - monotonic and present a sign change, opening the exciting possibility of controlling the transverse magnon flow direction and magnitude with the temperature change.
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arxiv:2403.07169
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the non - thermal, non - pulsed x - ray emission of msps is investigated. as in young pulsars, msps emit a relativistic wind, which interacting with the interstellar medium and / or a binary companion can significantly contribute to the non - pulsed emission of these pulsars. an application and extension of a simple model developed for young pulsars is applied to the old recycled msp b1957 + 20. it is found that the pulsar wind can, indeed, contribute to both the resolved and unresolved x - ray emission. for other msp in the galactic field where the spectral index of the non - pulsed component has been measured ( i. e., psr b1937 + 21, j0218 + 4232 ) the contribution of the pulsar wind to the non - pulsed x - ray luminosity is estimated. for the msps in the core regions of globular clusters, the pulsar wind nebula is likely affected by its interaction with the dense stellar environment, possibly leading to a diminished contribution to the total x - ray emission. in this case, the existence of non - thermal non - pulsed x - ray emission is more likely for binary rather than isolated msps with the emission arising from the interaction of the relativistic pulsar wind with a binary companion. our study suggests that the magnetization parameter in the pulsar wind nebulae of msps is significantly larger than that of the crab nebula by about a factor of 10. the emission from msps moving at high velocities may appear spatially extended with a tail - like morphology, which may contribute to the faint filamentary x - ray source subpopulation in the galaxy.
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arxiv:astro-ph/0602609
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in 2009, cygnus x - 3 ( cyg x - 3 ) became the first microquasar to be detected in the gev { \ gamma } - ray regime, via the satellites fermi and agile. the addition of this new band to the observational toolbox holds promise for building a more detailed understanding of the relativistic jets of this and other systems. we present a rich dataset of radio, hard and soft x - ray, and { \ gamma } - ray observations of cyg x - 3 made during a flaring episode in 2010 may. we detect a ~ 3 - d softening and recovery of the x - ray emission, followed almost immediately by a ~ 1 - jy radio flare at 15 ghz, followed by a 4. 3 { \ sigma } { \ gamma } - ray flare ( e > 100 mev ) ~ 1. 5 d later. the radio sampling is sparse, but we use archival data to argue that it is unlikely the { \ gamma } - ray flare was followed by any significant unobserved radio flares. in this case, the sequencing of the observed events is difficult to explain in a model in which the { \ gamma } - ray emission is due to inverse compton scattering of the companion star ' s radiation field. our observations suggest that other mechanisms may also be responsible for { \ gamma } - ray emission from cyg x - 3.
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arxiv:1104.5248
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we study sum - free sets in sparse random subsets of even order abelian groups. in particular, we determine the sharp threshold for the following property : the largest such set is contained in some maximum - size sum - free subset of the group. this theorem extends recent work of balogh, morris and samotij, who resolved the case g = z _ { 2n }, and who obtained a weaker threshold ( up to a constant factor ) in general.
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arxiv:1310.3236
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i show that a spontaneous electric polarization is developed in the solution of the falicov - kimball model ( fkm ) by mapping the strong coupling limit of the model into an $ xxz $ spin 1 / 2 model with a magnetic field. in this way, i can determine the phase diagram of the strongly interacting model that shows a transition to a mixed valence regime containing two phases : orbital ordering and bose - einstein condensation of excitons with a built in electric polarization. the results are extended to the intermeditate and weak coupling regimes.
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arxiv:cond-mat/0207331
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dynamical systems in nature exhibit self - similar fractal space - time fluctuations on all scales indicating long - range correlations and therefore the statistical normal distribution with implicit assumption of independence, fixed mean and standard deviation cannot be used for description and quantification of fractal data sets. the author has developed a general systems theory which predicts the following ( i ) the fractal fluctuations signify an underlying eddy continuum, the larger eddies being the integrated mean of enclosed smaller - scale fluctuations. ( ii ) the probability distribution of eddy amplitudes and the variance ( square of eddy amplitude ) spectrum of fractal fluctuations follow the universal boltzmann inverse power law expressed as a function of the golden mean. the predicted distribution is very close to statistical normal distribution for moderate events within two standard deviations from the mean but exhibits a fat long tail that are associated with hazardous extreme events. continuous periodogram power spectral analyses of available ghcn annual total rainfall time series for the period 1900 to 2008 for indian and usa stations show that the power spectra and the corresponding probability distributions follow model predicted universal inverse power law form signifying an eddy continuum structure underlying the observed inter - annual variability of rainfall. global warming related atmospheric energy input will result in intensification of fluctuations of all scales and can be seen immediately in high frequency ( short - term ) fluctuations such as devastating floods / droughts resulting from excess / deficit annual, quasi - biennial and other shorter period ( years ) rainfall cycles.
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arxiv:1002.3230
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the choice of convolutional routines ( primitives ) to implement neural networks has a tremendous impact on their inference performance ( execution speed ) on a given hardware platform. to optimise a neural network by primitive selection, the optimal primitive is identified for each layer of the network. this process requires a lengthy profiling stage, iterating over all the available primitives for each layer configuration, to measure their execution time on the target platform. because each primitive exploits the hardware in different ways, new profiling is needed to obtain the best performance when moving to another platform. in this work, we propose to replace this prohibitively expensive profiling stage with a machine learning based approach of performance modeling. our approach speeds up the optimisation time drastically. after training, our performance model can estimate the performance of convolutional primitives in any layer configuration. the time to optimise the execution of large neural networks via primitive selection is reduced from hours to just seconds. our performance model is easily transferable to other target platforms. we demonstrate this by training a performance model on an intel platform and performing transfer learning to amd and arm processor devices with minimal profiled samples.
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arxiv:2010.10621
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we present a new machine learning technique which calculates a real - valued, time independent, finite dimensional hamiltonian matrix from only experimental data. a novel cost function is given along with a proof that the cost function has the theoretically correct hamiltonian as a global minimum. we present results based on data simulated on a classical computer and results based on simulations of quantum systems on ibm ' s ibmqx2 quantum computer. we conclude with a discussion on the limitations of this data driven framework, as well as several possible extensions of this work. we also note that algorithm presented in this article not only serves as an example of using domain knowledge to design a machine learning framework, but also as an example of using domain knowledge to improve the speed of such algorithm.
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arxiv:1911.12548
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blazars are active galactic nuclei characterized by relativistic jets launched in the vicinity of the central engine ( i. e. a supermassive black hole ), that are oriented close to our line of sight. their peculiar orientation makes them very efficient tracers of the overall jetted population, and due to their brightness they can be visible up to very high redshifts. a deep knowledge of these objects can provide fundamental clues to the models of formation and growth of the first supermassive black holes, but their search in the early universe must be careful and follow a systematic approach. the discovery in the last $ \ sim15 $ years of extremely massive blazars at very high redshifts ( $ m _ { \ rm bh } > 10 ^ 9m _ \ odot, \, z > 4 $ ) revolutionized our perception of their earliest evolution : there seem to be different formation epochs for extremely massive black holes hosted in jetted ( $ z \ sim4 $ ) and non - jetted systems ( $ z \ sim2. 5 $ ). this is not easy to explain, since one would expect that jetted sources accrete less efficiently. small differences in the population are also derived from the search of such high - $ z $ sources : we will go through the open questions in order to understand where the common knowledge stands and which steps must be undertaken to better understand the formation and common evolution of supermassive black holes and jets in the early universe.
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arxiv:2107.09940
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we present a novel solution procedure for initial boundary value problems. the procedure is based on an action principle, in which coordinate maps are included as dynamical degrees of freedom. this reparametrization invariant action is formulated in an abstract parameter space and an energy density scale associated with the space - time coordinates separates the dynamics of the coordinate maps and of the propagating fields. treating coordinates as dependent, i. e. dynamical quantities, offers the opportunity to discretize the action while retaining all space - time symmetries and also provides the basis for automatic adaptive mesh refinement ( amr ). the presence of unbroken space - time symmetries after discretization also ensures that the associated continuum noether charges remain exactly conserved. the presence of coordinate maps in addition provides new freedom in the choice of boundary conditions. an explicit numerical example for wave propagation in $ 1 + 1 $ dimensions is provided, using recently developed regularized summation - by - parts finite difference operators.
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arxiv:2404.18676
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in this paper, we consider the initial neumann boundary value problem for a degenerate kinetic model of keller - - segel type. the system features a signal - dependent decreasing motility function that vanishes asymptotically, i. e., degeneracies may take place as the concentration of signals tends to infinity. in the present work, we are interested in the boundedness of classical solutions when the motility function satisfies certain decay rate assumptions. roughly speaking, in the two - dimensional setting, we prove that classical solution is globally bounded if the motility function decreases slower than an exponential speed at high signal concentrations. in higher dimensions, boundedness is obtained when the motility decreases at certain algebraical speed. the proof is based on the comparison methods developed in our previous work \ cite { fj19a, fj19b } together with a modified alikakos - - moser type iteration. besides, new estimations involving certain weighted energies are also constructed to establish the boundedness.
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arxiv:2007.05728
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in this paper we study the convergence of a lie - trotter operator splitting for stochastic semi - linear evolution equations in a hilbert space. the abstract hilbert space setting allows for the consideration of convergence of the approximation for both the original and spatially discretized problems. it is known that the strong convergence of this scheme is classically of half - order, at best. we demonstrate that this is in fact the optimal order of convergence in the proposed setting, with the actual order being dependent upon the regularity of noise collected from applications.
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arxiv:1901.06371
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we construct universal prediction systems in the spirit of popper ' s falsifiability and kolmogorov complexity and randomness. these prediction systems do not depend on any statistical assumptions ( but under the iid assumption they dominate, to within the usual accuracy, conformal prediction ). our constructions give rise to a theory of algorithmic complexity and randomness of time containing analogues of several notions and results of the classical theory of kolmogorov complexity and randomness.
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arxiv:1603.04283
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the dual $ f $ - signature is a numerical invariant defined via the frobenius morphism in positive characteristic. it is known that the dual $ f $ - signature characterizes some singularities. however, the value of the dual $ f $ - signature is not known except only a few cases. in this paper, we determine the dual $ f $ - signature of cohen - macaulay modules over two - dimensional rational double points. the method for determining the dual $ f $ - signature is also valid for determining the hilbert - kunz multiplicity. we discuss it in appendix.
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arxiv:1407.5230
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we prove a maximum principle for the problem of optimal control for a fractional diffusion with infinite horizon. further, we show existence of fractional backward stochastic differential equations on infinite horizon. we illustrate our findings with an example.
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arxiv:1206.3432
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exploiting higher - order derivatives in convex optimization is known at least since 1970 ' s. in each iteration higher - order ( also called tensor ) methods minimize a regularized taylor expansion of the objective function, which leads to faster convergence rates if the corresponding higher - order derivative is lipschitz - continuous. recently a series of lower iteration complexity bounds for such methods were proved, and a gap between upper an lower complexity bounds was revealed. moreover, it was shown that such methods can be implementable since the appropriately regularized taylor expansion of a convex function is also convex and, thus, can be minimized in polynomial time. only very recently an algorithm with optimal convergence rate $ 1 / k ^ { ( 3p + 1 ) / 2 } $ was proposed for minimizing convex functions with lipschitz $ p $ - th derivative. for convex functions with lipschitz third derivative, these developments allowed to propose a second - order method with convergence rate $ 1 / k ^ 5 $, which is faster than the rate $ 1 / k ^ { 3. 5 } $ of existing second - order methods.
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arxiv:2208.13190
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recent developments in natural language processing have demonstrated the potential of large language models ( llms ) to improve a range of educational and learning outcomes. of recent chatbots based on llms, chatgpt and bard have made it clear that artificial intelligence ( ai ) technology will have significant implications on the way we obtain and search for information. however, these tools sometimes produce text that is convincing, but often incorrect, known as hallucinations. as such, their use can distort scientific facts and spread misinformation. to counter polarizing responses on these tools, it is critical to provide an overview of such responses so stakeholders can determine which topics tend to produce more contentious responses - - key to developing targeted regulatory policy and interventions. in addition, there currently exists no annotated dataset of chatgpt and bard responses around possibly polarizing topics, central to the above aims. we address the indicated issues through the following contribution : focusing on highly polarizing topics in the us, we created and described a dataset of chatgpt and bard responses. broadly, our results indicated a left - leaning bias for both chatgpt and bard, with bard more likely to provide responses around polarizing topics. bard seemed to have fewer guardrails around controversial topics, and appeared more willing to provide comprehensive, and somewhat human - like responses. bard may thus be more likely abused by malicious actors. stakeholders may utilize our findings to mitigate misinformative and / or polarizing responses from llms
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arxiv:2307.12402
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an a - infinity algebra is given by a codifferential on the tensor coalgebra of a ( graded ) vector space. an associative algebra is a special case of an a - infinity algebra, determined by a quadratic codifferential. the notions of hochschild and cyclic cohomology generalize from associative to a - infinity algebras, and classify the infinitesimal deformations of the algebra, and those deformations preserving an invariant inner product, respectively. similarly, an l - infinity algebra is given by a codifferential on the exterior coalgebra of a vector space, with lie algebras being special cases given by quadratic codifferentials. there are natural definitions of cohomology and cyclic cohomology, generalizing the usual lie algebra cohomology and cyclic cohomology, which classify deformations of the algebra and those which preserve an invariant inner product. this article explores the definitions of these infinity algebras, their cohomology and cyclic cohomology, and the relation to their infinitesimal deformations.
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arxiv:math/0111088
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the brick wall model is a semi - classical approach to understanding the microscopic origin of black hole entropy. we outline the formalism for the brick wall model in arbitrary number of dimensions and generalize it to include both charged spacetimes and charged probes in order to systematically show how to calculate the entropy for any black hole, in higher orders of the wkb approximation. we calculate the entropy for the reissner - nordstr \ " { o } m and charged btz black holes, and by looking at the chargeless limits we recover the entropy of the schwarzschild and neutral btz black holes. we also study noncommutative corrections to the black hole entropy by using a drinfeld twist to deform spacetime symmetries. using the noncommutative action for a charged scalar field, we derive the noncommutative klein - gordon equation and the radial equation in arbitrary dimension on which we generalize the brick wall method. we study case by case the noncommutative reissner - nordstr \ " { o } m and noncommutative charged btz black holes, the entropy of which we calculate using the generalized brick wall method. corrections due to higher order in the wkb approximation arise, and they are given by the logarithms of the black hole area. the corrections in the lowest order of wkb due to noncommutativity are also given by the logarithms of the black hole area.
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arxiv:2407.13233
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we study the ` enhancon ', a spherical hypersurface apparently made of d - branes, which arises in string theory studies of large n su ( n ) pure gauge theories with eight supercharges. when the gauge theory is 2 + 1 dimensional, the enhancon is an s ^ 2. a relation to charge n bps multi - monopoles is exploited to uncover many of its detailed properties. it is simply a spherical slice through an atiyah - hitchin - like submanifold of the charge $ n $ bps monopole moduli space. in the form of nahm data, it is built from the n dimensional irreducible representation of su ( 2 ). in this sense the enhancon is a non - commutative sphere, reminiscent of the spherical ` dielectric ' branes of myers.
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arxiv:hep-th/0004068
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big bang nucleosynthesis ( bbn ) offers one of the most strict evidences for the lambda - cdm cosmology at present, as well as the cosmic microwave background ( cmb ) radiation. in this work, our main aim is to present the outcomes of our calculations related to primordial abundances of light elements, in the context of higher dimensional steady - state universe model in the dilaton gravity. our results show that abundances of light elements ( primordial d, 3he, 4he, t, 7li ) are significantly different for some cases, and a comparison is given between a particular dilaton gravity model and lambda - cdm in the light of the astrophysical observations.
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arxiv:1310.6145
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the objective of this paper is to share our enthusiasm for optical pumping experiments and to encourage their use in researches on practical physics. the experimental technique has been well developed and the apparatus sophisticated, but, by paying attention to a few details, reliable operation can be repeated. some theoretical principles for optical pumping are also introduced and they can be demonstrated experimentally.
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arxiv:0810.2579
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an elementary derivation of the chiral gauge anomaly in all even dimensions is given in terms of noncommutative traces of pseudo - differential operators.
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arxiv:hep-th/9412129
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three - dimensional models of craniofacial variation over the general population are useful for assessing pre - and post - operative head shape when treating various craniofacial conditions, such as craniosynostosis. we present a new method of automatically building both sagittal profile models and full 3d surface models of the human head using a range of techniques in 3d surface image analysis ; in particular, automatic facial landmarking using supervised machine learning, global and local symmetry plane detection using a variant of trimmed iterative closest points, locally - affine template warping ( for full 3d models ) and a novel pose normalisation using robust iterative ellipse fitting. the pca - based models built using the new pose normalisation are more compact than those using generalised procrustes analysis and we demonstrate their utility in a clinical case study.
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arxiv:1601.05593
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experimental and theoretical developments of the last decade in the study of exotic atoms and some related low - energy reactions are reviewed, in order to provide information on the in - medium hadron - nucleon t matrix over a wide range of densities up to central nuclear densities. in particular, we review pionic deeply bound atomic states and related evidence for partial restoration of chiral symmetry in dense nuclear matter. the case for relatively narrow deeply bound atomic states for antikaons and antiprotons is made, based on the physics of strong nuclear absorption. recent experimental suggestions for signals of antikaon - nuclear deeply bound states are reviewed, and dynamical models for calculating binding energies, widths and densities of antikaon nuclear states are discussed. specific features of low - energy in - medium interactions of kaons, antiprotons and of sigma hyperons are discussed, and suggestions to study experimentally cascade atoms are reviewed.
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arxiv:0705.3965
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given a network and a subset of interesting vertices whose identities are only partially known, the vertex nomination problem seeks to rank the remaining vertices in such a way that the interesting vertices are ranked at the top of the list. an important variant of this problem is vertex nomination in the multi - graphs setting. given two graphs $ g _ 1, g _ 2 $ with common vertices and a vertex of interest $ x \ in g _ 1 $, we wish to rank the vertices of $ g _ 2 $ such that the vertices most similar to $ x $ are ranked at the top of the list. the current paper addresses this problem and proposes a method that first applies adjacency spectral graph embedding to embed the graphs into a common euclidean space, and then solves a penalized linear assignment problem to obtain the nomination lists. since the spectral embedding of the graphs are only unique up to orthogonal transformations, we present two approaches to eliminate this potential non - identifiability. one approach is based on orthogonal procrustes and is applicable when there are enough vertices with known correspondence between the two graphs. another approach uses adaptive point set registration and is applicable when there are few or no vertices with known correspondence. we show that our nomination scheme leads to accurate nomination under a generative model for pairs of random graphs that are approximately low - rank and possibly with pairwise edge correlations. we illustrate our algorithm ' s performance through simulation studies on synthetic data as well as analysis of a high - school friendship network and analysis of transition rates between web pages on the bing search engine.
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arxiv:2010.14622
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near - term quantum simulators are mostly based on qubit - based architectures. however, their imperfect nature significantly limits their practical application. the situation is even worse for simulating fermionic systems, which underlie most of material science and chemistry, as one has to adopt fermion - to - qubit encodings which create significant additional resource overhead and trainability issues. thanks to recent advances in trapping and manipulation of neutral atoms in optical tweezers, digital fermionic quantum simulators are becoming viable. a key question is whether these emerging fermionic simulators can outperform qubit - based simulators for characterizing strongly correlated electronic systems. here, we perform a comprehensive comparison of resource efficiency between qubit and fermionic simulators for variational ground - state emulation of fermionic systems in both condensed matter systems and quantum chemistry problems. we show that the fermionic simulators indeed outperform their qubit counterparts with respect to resources for quantum evolution ( circuit depth ), as well as classical optimization ( number of required parameters and iterations ). in addition, they show less sensitivity to the random initialization of the circuit. the relative advantage of fermionic simulators becomes even more pronounced as interaction becomes stronger, or tunneling is allowed in more than one dimension, as well as for spinful fermions. importantly, this improvement is scalable, i. e., the performance gap between fermionic and qubit simulators only grows for bigger system sizes.
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arxiv:2306.14842
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a series on nanocrystalline fe100 - xcrx alloys prepared by mechanical alloying was investigated with x - ray diffraction ( xrd ), scanning electron microscopy ( sem ) and m \ " ossbauer spectroscopy ( ms ) techniques. xrd and sem were used to structurally characterize the samples whereas ms permitted phase analysis as well as determination of the debye temperature, theta _ d. concerning the latter, an enhancement relative to bulk theta _ d - values was revealed in the range of ca. 40 < x < 50. in a sample of fe55. 5cr44. 5 two phases were detected viz. ( 1 ) crystalline and magnetic with theta _ d = 572 ( 56 ) k and ( 2 ) amorphous and paramagnetic with theta _ d = 405 ( 26 ) k.
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arxiv:1505.06374
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detecting and evaluating surface coating defects is important for marine vessel maintenance. currently, the assessment is carried out manually by qualified inspectors using international standards and their own experience. automating the processes is highly challenging because of the high level of variation in vessel type, paint surface, coatings, lighting condition, weather condition, paint colors, areas of the vessel, and time in service. we present a novel deep learning - based pipeline to detect and evaluate the percentage of corrosion, fouling, and delamination on the vessel surface from normal photographs. we propose a multi - stage image processing framework, including ship section segmentation, defect segmentation, and defect classification, to automatically recognize different types of defects and measure the coverage percentage on the ship surface. experimental results demonstrate that our proposed pipeline can objectively perform a similar assessment as a qualified inspector.
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arxiv:2203.09580
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malware still constitutes a major threat in the cybersecurity landscape, also due to the widespread use of infection vectors such as documents. these infection vectors hide embedded malicious code to the victim users, facilitating the use of social engineering techniques to infect their machines. research showed that machine - learning algorithms provide effective detection mechanisms against such threats, but the existence of an arms race in adversarial settings has recently challenged such systems. in this work, we focus on malware embedded in pdf files as a representative case of such an arms race. we start by providing a comprehensive taxonomy of the different approaches used to generate pdf malware, and of the corresponding learning - based detection systems. we then categorize threats specifically targeted against learning - based pdf malware detectors, using a well - established framework in the field of adversarial machine learning. this framework allows us to categorize known vulnerabilities of learning - based pdf malware detectors and to identify novel attacks that may threaten such systems, along with the potential defense mechanisms that can mitigate the impact of such threats. we conclude the paper by discussing how such findings highlight promising research directions towards tackling the more general challenge of designing robust malware detectors in adversarial settings.
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arxiv:1811.00830
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we present a simple isospin invariant parametrization for $ ( b \ to k \ pi ) $ decay amplitudes which consistently includes cp violation and ( quasi - elastic ) hadronic final states interactions. we find that the observed $ ( b \ to k \ pi ) $ decays do not lead to a significant bound on the angle $ \ gamma $ of the unitarity triangle. on the other hand, we claim that a sizeable cp violation asymmetry in $ ( b ^ { \ pm } \ to k \ pi ^ { \ pm } ) $ rates is by no means excluded.
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arxiv:hep-ph/9711469
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operations research deals with modeling and solving real - world problems as mathematical optimization problems. while solving mathematical systems is accomplished by analytical software, formulating a problem as a set of mathematical operations has been typically done manually by domain experts. recent machine learning methods have shown promise in converting textual problem descriptions to corresponding mathematical formulations. this paper presents an approach that converts linear programming word problems into mathematical formulations. we leverage the named entities in the input and augment the input to highlight these entities. our approach achieves the highest accuracy among all submissions to the nl4opt competition, securing first place in the generation track.
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arxiv:2212.13201
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we present citnetexplorer, a new software tool for analyzing and visualizing citation networks of scientific publications. citnetexplorer can for instance be used to study the development of a research field, to delineate the literature on a research topic, and to support literature reviewing. we first introduce the main concepts that need to be understood when working with citnetexplorer. we then demonstrate citnetexplorer by using the tool to analyze the scientometric literature and the literature on community detection in networks. finally, we discuss some technical details on the construction, visualization, and analysis of citation networks in citnetexplorer.
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arxiv:1404.5322
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efficient solution of 3d elasticity problems is an important part of many industrial and scientific applications. smoothed aggregation algebraic multigrid using rigid body modes for the tentative prolongation operator construction is an efficient and robust choice for the solution of linear systems arising from the discretization of elasticity equations. the system matrices on every level of the multigrid hierarchy have block structure, so using block representation and block arithmetics should significantly improve the solver efficiency. however, the tentative prolongation operator construction may only be done using scalar representation. the paper proposes a couple of practical approaches for enabling the use of block arithmetics with smoothed aggregation algebraic multigrid based on the open - source amgcl library. it is shown on the example of two real - world model problems that the suggested improvements may speed up the solution by 50 % and reduce the memory requirements for the preconditioner by 30 %. the implementation is straightforward and only requires a minimal amount of code.
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arxiv:2202.09056
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we prove that the system resulting of coupling the standard map with a fast hyperbolic system is robustly non - uniformly hyperbolic.
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arxiv:1211.3380
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full radiative transfer in 3d space has been solved to pursue the reionization history in an inhomogeneous universe. it has been shown that the reionization of an inhomogeneous universe is not a prompt event, but a fairly slow process. also, qso absorption line systems are simulated with using the results of radiative transfer calculations. ly $ \ alpha $ continuum depression implies that the metagalactic uv intensity decreases rapidly with $ z $ at $ z > 5 $, and the reionization must have taken place between $ z = 6 $ and 10. finally, it is stressed that h $ \ alpha $ forest is a more powerful tool to probe the reionization history and the density fluctuations in the universe at $ z > 5 $.
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arxiv:astro-ph/0108176
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we present psl, a lightweight, secure and stateful function - as - a - serivce ( faas ) framework for trusted execution environments ( tees ). the framework provides rich programming language support on heterogeneous tee hardware for statically compiled binaries and / or webassembly ( wasm ) bytecodes, with a familiar key - value store ( kvs ) interface to secure, performant, network - embedded storage. it achieves near - native execution speeds by utilizing the dynamic memory mapping capabilities of intel sgx2 to create an in - enclave wasm runtime with just - in - time ( jit ) compilation. psl is designed to efficiently operate within an asynchronous environment with a distributed tamper - proof confidential storage system, assuming minority failures. the system exchanges eventually - consistent state updates across nodes while utilizing release - consistent locking mechanisms to enhance transactional capabilities. the execution of psl is up to 3. 7x faster than the state - of - the - art sgx wasm runtime. psl reaches 95k ops / s with ycsb 100 % read workload and 89k ops / s with 50 % read / write workload. we demonstrate the scalability and adaptivity of psl through a case study of secure and distributed training of deep neural networks.
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arxiv:2410.20004
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