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a new approach for the calculation of collisional inverse bremsstrahlung absorption of laser light in dense plasmas is presented. quantum statistical formalism used allows avoiding { \ em ad hoc } cutoffs that were necessary in classical approaches. thus, the current method remains reliable for strong electron - ion interactions. in addition, both the dynamic, field dependent response and hard electron - ion collisions, are consistently incorporated. the latter were treated in an average manner as a stopping power that in turn was cast into a form of a friction force. here, for the first time a link between the stopping power and the problem of collisional laser absorption is drawn. this allows the theories developed for the stopping power calculation, such as the quantum t - matrix approach, to be applied to the problem of collisional laser absorption. the new approach accommodates the low - and high - frequency limits explained in the text and is valid for arbitrary laser field intensities. a comparison with classical md simulation is indicative of the validity of the new method in the wide parameter range tested.
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arxiv:0905.4374
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this work investigates the influence of a probe string on the complexity of braneworld according to the ca ( complexity equals action ) conjecture within the horndeski gravity. in the current study, it is considered that scalar fields that source horndeski gravity has a spatial dependence. in addition, our system contains a particle moving on the boundary, which corresponds to the insertion of a fundamental string in the higher dimensional bulk. such an effect is given by the nambu - goto term, which also incorporates the time - dependence and evolution in our system. both warp factor, scalar field, and superpotential values are derived numerically assuming appropriate initial conditions, and the growth rate of holographic complexity is analyzed within the so - called wheeler - de witt ( wdw ) patch with null - like hypersurfaces present.
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arxiv:2210.11596
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we construct an operational calculus supported on the algebraic operational calculus introduced by bengochea and verde. with this operational calculus we study the solution of certain bessel type equations.
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arxiv:1305.6562
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we propose superluminal solitons residing in the momentum gap ( k - gap ) of nonlinear photonic time - crystals. these gap solitons are structured as plane - waves in space while being periodically self - reconstructing wavepackets in time. the solitons emerge from modes with infinite group velocity causing superluminal evolution, which is opposite to the stationary nature of the analogous bragg gap soliton residing at the edge of an energy gap ( or a spatial gap ) with zero group velocity. we explore the faster - than - light pulsed propagation of these k - gap solitons in view of einstein ' s causality by introducing a truncated input seed as a precursor of signal velocity forerunner, and find that the superluminal propagation of k - gap solitons does not break causality.
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arxiv:2208.09220
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wheeler ' s conjectured " spacetime foam " - - large quantum fluctuations of spacetime at the planck scale - - could have important implications for quantum gravity, perhaps even explaining why the cosmological constant seems so small. here i explore this problem in a midisuperspace model consisting of metrics with local spherical symmetry. classically, an infinite class of ` ` foamy ' ' initial data can be constructed, in which cancellations between expanding and contracting regions lead to a small average expansion even if $ \ lambda $ is large. quantum mechanically, the model admits corresponding stationary states, for which the probability current is also nearly zero. these states appear to describe a self - reproducing spacetime foam with very small average expansion, effectively hiding the cosmological constant.
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arxiv:2106.09751
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we study the entanglement properties of a class of ground states defined by matrix product states, which are generalizations of the valence bond solid ( vbs ) state in one dimension. it is shown that the transfer matrix of these states can be related to representations of the temperley - lieb algebra, allowing an exact computation of renyi entropy. for an alternating bipartition, we find that the renyi entropy can be mapped to an eight vertex model partition function on a rotated lattice. we also show that for the vbs state, the renyi entropy of the alternating partition is described by a critical field theory with central charge $ c = 1 $. the generalization to $ su ( n ) $ vbs and its connection with a dimerization transition in the entanglement hamiltonian is discussed.
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arxiv:1408.1716
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a spherically symmetric distribution of classical blackbody radiation is considered, at conditions in which gravitational self - interaction effects become not negligible. static solutions to einstein field equations are searched for, for each choice of the assumed central energy density. spherical cavities at thermodynamic equilibrium, i. e. filled with blackbody radiation, are then studied, in particular for what concerns the relation among the mass m of the ball of radiation contained in them and their temperature at center and at the boundary. for these cavities it is shown, in particular, that : i ) there is no absolute limit to m as well to their central and boundary temperatures ; ii ) when radius r is fixed, however, limits exist both for mass and for boundary energy density rho _ b : m < = k m _ s ( r ) and rho _ b < = q / r ^ 2, with k = 0. 493 and q = 0. 02718, dimensionless, and m _ s ( r ) the schwarzschild mass for that radius. some implications of the existence and the magnitude of these limits are considered. finally the radial profiles for entropy for these systems are studied, in their dependence on the mass ( or central temperature ) of the ball of radiation.
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arxiv:gr-qc/0603097
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a study of the distribution of oh gas in the central region of the nearby active starburst galaxy m82 has confirmed two previously known bright masers and revealed several new main line masers. three of these are seen only at 1665 mhz, one is detected only at 1667 mhz, while the rest are detected in both lines. observations covering both the 1665 and 1667 mhz lines, conducted with both the very large array ( vla ) and the multi - element radio linked interferometer network ( merlin ), have been used to accurately measure the positions and velocities of these features. this has allowed a comparison with catalogued continuum features in the starburst such as hii regions and supernova remnants, as well as known water and satellite line oh masers. most of the main line masers appear to be associated with known hii regions although the two detected only at 1665 mhz are seen along the same line of sight as known supernova remnants.
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arxiv:0706.1149
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the basic financial purpose of an enterprise is maximization of its value. trade credit management should also contribute to realization of this fundamental aim. many of the current asset management models that are found in financial management literature assume book profit maximization as the basic financial purpose. these book profitbased models could be lacking in what relates to another aim ( i. e., maximization of enterprise value ). the enterprise value maximization strategy is executed with a focus on risk and uncertainty. this article presents the consequences that can result from operating risk that is related to purchasers using payment postponement for goods and / or services. the present article offers a method that uses portfolio management theory to determine the level of accounts receivable in a firm. an increase in the level of accounts receivables in a firm increases both net working capital and the costs of holding and managing accounts receivables. both of these decrease the value of the firm, but a liberal policy in accounts receivable coupled with the portfolio management approach could increase the value. efforts to assign ways to manage these risks were also undertaken ; among them, special attention was paid to adapting assumptions from portfolio theory as well as gauging the potential effect on the firm value.
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arxiv:1301.3823
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we consider the massless tricritical ising model m ( 4, 5 ) perturbed by the thermal operator in a cylindrical geometry and apply integrable boundary conditions, labelled by the kac labels ( r, s ), that are natural off - critical perturbations of known conformal boundary conditions. we derive massless thermodynamic bethe ansatz ( tba ) equations for all excitations by solving, in the continuum scaling limit, the tba functional equation satisfied by the double - row transfer matrices of the a _ 4 lattice model of andrews, baxter and forrester ( abf ) in regime iv. the resulting tba equations describe the massless renormalization group flow from the tricritical to critical ising model. as in the massive case of part i, the excitations are completely classified in terms of ( m, n ) systems but the string content changes by one of three mechanisms along the flow. using generalized q - vandemonde identities, we show that this leads to a flow from tricritical to critical ising characters. the excited tba equations are solved numerically to follow the continuous flows from the uv to the ir conformal fixed points.
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arxiv:hep-th/0302093
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we present a method of design of control systems for $ n $ bodies in the real line $ \ bbb r ^ 1 $ and on the unit circle $ s ^ 1 $, to be collision - free and controllable. the problem reduces to designing a control - affine system in $ \ bbb r ^ n $ and in $ n $ - torus $ t ^ n, $ respectively, that avoids certain obstacles. we prove the controllability of the system by showing that the vector fields that define the control - affine system, together with their brackets of first order, span the whole tangent space of the state space, and then by applying the rashevsky - chow theorem.
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arxiv:2209.10824
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the unprecedented sensitivity of herschel coupled with the high resolution of the hifi spectrometer permits studies of the intensity - velocity relationship i ( v ) in molecular outflows, over a higher excitation range than possible up to now. in the course of the chess key program, we have observed toward the bright bowshock region l1157 - b1 the co rotational transitions between j = 5 - 4 and j = 16 - 15 with hifi, and the j = 1 - 0, 2 - 1 and 3 - 2 with the iram - 30m and the cso telescopes. we find that all the line profiles i _ { co } ( v ) are well fit by a linear combination of three exponential laws exp ( - | v / v _ 0 | ) with v _ 0 = 12. 5, 4. 4 and 2. 5km / s. the first component dominates the co emission at j _ up > 13, as well as the high - excitation lines of sio and h2o. the second component dominates for 3 < j _ up < 10 and the third one for j _ up < 2. we show that these exponentials are the signature of quasi - isothermal shocked gas components : the impact of the jet against the l1157 - b1 bowshock ( t = 210k ), the walls of the outflow cavity associated with b1 ( t = 64k ) and the older cavity l1157 - b2 ( t = 23k ), respectively. analysis of the co line flux in the large - velocity gradient approximation further shows that the emission arises from dense gas ( n ( h2 ) > 1e5 - 1e6 cm - 3 ) close to lte up to j = 20. we find that the co j = 2 - 1 intensity - velocity relation observed in various other molecular outflows is satisfactorily fit by similar exponential laws, which may hold an important clue to their entrainment process.
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arxiv:1208.4140
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starting from the standard form of the five discrete painlev \ ' e equations we show how one can obtain ( through appropriate limits ) a host of new equations which are also the discrete analogues of the continuous painlev \ ' e equations. a particularly interesting technique is the one based on the assumption that some simplification takes place in the autonomous form of the mapping following which the deautonomization leads to a new $ n $ - dependence and introduces more new discrete painlev \ ' e equations.
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arxiv:solv-int/9510011
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recent models of emotion recognition strongly rely on supervised deep learning solutions for the distinction of general emotion expressions. however, they are not reliable when recognizing online and personalized facial expressions, e. g., for person - specific affective understanding. in this paper, we present a neural model based on a conditional adversarial autoencoder to learn how to represent and edit general emotion expressions. we then propose grow - when - required networks as personalized affective memories to learn individualized aspects of emotion expressions. our model achieves state - of - the - art performance on emotion recognition when evaluated on \ textit { in - the - wild } datasets. furthermore, our experiments include ablation studies and neural visualizations in order to explain the behavior of our model.
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arxiv:1904.12632
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a new x - ray transient, designated xte j1739 - 302, was discovered with the proportional counter array ( pca ) on the rossi x - ray timing explorer ( rxte ) in data from 12 august 1997. although it was the brightest source in the galactic center region while active ( about 3. 0 x 10 ^ - 9 ergs / cm2 / s from 2 to 25 kev ), it was only observed on that one day ; it was not detectable nine days earlier or two days later. there is no known counterpart at other wavelengths, and its proximity to the galactic center will make such an identification difficult due to source confusion and extinction. the x - ray spectrum and intensity suggest a giant outburst of a be / neutron star binary, although no pulsations were observed and the outburst was shorter than is usual from these systems.
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arxiv:astro-ph/9805178
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the dynamical behavior of the magnetism of diluted magnetic semiconductors ( dms ) has been investigated by means of atomistic spin dynamics simulations. the conclusions drawn from the study are argued to be general for dms systems in the low concentration limit, although all simulations are done for 5 % mn - doped gaas with various concentrations of as antisite defects. the magnetization curve, $ m ( t ) $, and the curie temperature $ t _ c $ have been calculated, and are found to be in good correspondence to results from monte carlo simulations and experiments. furthermore, equilibrium and non - equilibrium behavior of the magnetic pair correlation function have been extracted. the dynamics of dms systems reveals a substantial short ranged magnetic order even at temperatures at or above the ordering temperature, with a non - vanishing pair correlation function extending up to several atomic shells. for the high as antisite concentrations the simulations show a short ranged anti - ferromagnetic coupling, and a weakened long ranged ferromagnetic coupling. for sufficiently large concentrations we do not observe any long ranged ferromagnetic correlation. a typical dynamical response shows that starting from a random orientation of moments, the spin - correlation develops very fast ( $ \ sim $ 1ps ) extending up to 15 atomic shells. above $ \ sim $ 10 ps in the simulations, the pair correlation is observed to extend over some 40 atomic shells. the autocorrelation function has been calculated and compared with ferromagnets like bcc fe and spin - glass materials. we find no evidence in our simulations for a spin - glass behaviour, for any concentration of as antisites. instead the magnetic response is better described as slow dynamics, at least when compared to that of a regular ferromagnet like bcc fe.
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arxiv:0809.5187
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in this paper, we propose and analyse a novel class of exponential collocation methods for solving conservative or dissipative systems based on exponential integrators and collocation methods. it is shown that these novel methods can be of arbitrarily high order and exactly or nearly preserve first integrals or lyapunov functions. we also consider order estimates of the new methods. furthermore, we explore and discuss the application of our methods in important stiff gradient systems, and it turns out that our methods are unconditionally energy - diminishing and strongly damped even for very stiff gradient systems. practical examples of the new methods are derived and the efficiency and superiority are confirmed and demonstrated by three numerical experiments including a nonlinear schr \ " { o } dinger equation. as a byproduct of this paper, arbitrary - order trigonometric / rkn collocation methods are also presented and analysed for second - order highly oscillatory / general systems. the paper is accompanied by numerical results that demonstrate the great potential of this work.
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arxiv:1712.07830
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the dynamics of grain ejection consecutive to a sphere impacting a granular material is investigated experimentally and the variations of the characteristics of grain ejection with the control parameters are quantitatively studied. the time evolution of the corona formed by the ejected grains is reported, mainly in terms of its diameter and height, and favourably compared with a simple ballistic model. a key characteristic of the granular corona is that the angle formed by its edge with the horizontal granular surface remains constant during the ejection process, which again can be reproduced by the ballistic model. the number and the kinetic energy of the ejected grains is evaluated and allows for the calculation of an effective restitution coefficient characterizing the complex collision process between the impacting sphere and the fine granular target. the effective restitution coefficient is found to be constant when varying the control parameters.
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arxiv:0808.2295
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the problem of increasing the accuracy of an approximate solution is considered for boundary value problems for parabolic equations. for ordinary differential equations ( odes ), nonstandard finite difference schemes are in common use for this problem. they are based on a modification of standard discretizations of time derivatives and, in some cases, allow to obtain the exact solution of problems. for multidimensional problems, we can consider the problem of increasing the accuracy only for the most important components of the approximate solution. in the present work, new unconditionally stable schemes for parabolic problems are constructed, which are exact for the fundamental mode. such two - level schemes are designed via a modification of standard schemes with weights using pad \ ' { e } approximations. numerical results obtained for a model problem demonstrate advantages of the proposed fundamental mode exact schemes.
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arxiv:1705.07010
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our concern is the completeness problem for spi - logics, that is, sets of implications between strictly positive formulas built from propositional variables, conjunction and modal diamond operators. originated in logic, algebra and computer science, spi - logics have two natural semantics : meet - semilattices with monotone operators providing birkhoff - style calculi, and first - order relational structures ( aka kripke frames ) often used as the intended structures in applications. here we lay foundations for a completeness theory that aims to answer the question whether the two semantics define the same consequence relations for a given spi - logic.
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arxiv:1708.03403
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using scanning tunneling spectroscopy we have studied the effects of nitrogen gas exposure on the bismuth selenide density of states. we observe a shift in the dirac point which is qualitatively consistent with theoretical modeling of nitrogen binding to selenium vacancies. in carefully controlled measurements, bi $ _ 2 $ se $ _ 3 $ crystals were initially cleaved in a helium gas environment and then exposed to a 22 scfh flow of ultra - high purity n $ _ 2 $ gas. we observe a resulting change in the spectral curves, with the exposure effect saturating after approximately 50 minutes, ultimately bringing the dirac point about 50 mev closer to the fermi level. these results are compared to density functional theoretical calculations, which support a picture of $ n _ 2 $ molecules physisorbing near se vacancies and dissociating into individual n atoms which then bind strongly to se vacancies. in this interpretation, the binding of the n atom to a se vacancy site removes the surface defect state created by the vacancy and changes the position of the fermi energy with respect to the dirac point.
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arxiv:2004.01631
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the tajmar anomaly is an unexplained acceleration observed by gyroscopes close to, but isolated from, rotating rings cooled to 5k. the observed ratio between the gyroscope and ring accelerations was 3 + / - 1. 2 * 10 ^ - 8 for clockwise rotations and about half this size for anticlockwise ones. here, this anomaly is predicted using a new model that assumes that the inertial mass of the gyroscope is caused by unruh radiation that appears as the ring and the fixed stars accelerate relative to it, and that this radiation is subject to a hubble - scale casimir effect. the model predicts that the sudden acceleration of the ring causes a slight increase in the inertial mass of the gyroscope, and, to conserve momentum the gyroscope must move with the ring with an acceleration ratio of 2. 67 + / - 0. 24 * 10 ^ - 8 for clockwise rotations and 1. 34 + / - 0. 12 * 10 ^ - 8 for anticlockwise ones, in agreement with the observations. the model predicts that in the southern hemisphere the anomaly should be larger for anticlockwise rotations instead, and that with a significant reduction of the mass of the disc, the decay of the effect with vertical distance should become measurable.
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arxiv:1106.3266
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the contribution of a chiral three - nucleon force to the strength of an effective spin - orbit coupling is estimated. we first construct a reduced two - body interaction by folding one - nucleon degrees of freedom of the three - nucleon force in nuclear matter. the spin - orbit strength is evaluated by a scheerbaum factor obtained by the $ g $ - matrix calculation in nuclear matter with the two - nucleon interaction plus the reduced two - nucleon interaction. the problem of the insufficiency of modern realistic two - nucleon interactions to account for the empirical spin - orbit strength is resolved. it is also indicated that the spin - orbit coupling is weaker in the neutron - rich environment. because the spin - orbit component from the three - nucleon force is determined by the low - energy constants fixed in the two - nucleon sector, there is little uncertainty in the present estimation.
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arxiv:1209.5048
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the perturbative qcd corrections to the nonleptonic decay rate of the $ b $ quark are discussed. by considering the limit where the final charmed quarks are slow, it is argued that the coefficients of the $ \ alpha _ s ^ 2 $ terms, corresponding to next - to - next - to - leading order in the standard renormalization group expansion in $ \ ln ( m _ w / m _ b ) $, are naturally large. the large coefficients arise from the final - state gluon exchange between quarks and are associated with the region of rather low momenta, which may further enhance the phenomenological significance of these terms.
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arxiv:hep-ph/9602256
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we present an extension of the two - point optical microrheology technique introduced by crocker \ textit { et al. } [ phys. rev. lett. \ textbf { 85 }, 888 ( 2000 ) ] to high frequencies. the correlated fluctuations of two probe spheres held by a pair of optical tweezers within a viscoelastic medium are determined using optical interferometry. a theoretical model is developed to yield the frequency - dependent one - and two - particle response functions from the correlated motion. we demonstrate the validity of this method by determining the one - and two - particle correlations in a semi - dilute solution of polystyrene in decalin. we find that the ratio of the one - and two - particle response functions is anomalous which we interpret as evidence for a slip boundary condition caused by depletion of polymer from the surface of the particle.
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arxiv:cond-mat/0205309
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it is well known that a weak solution $ \ varphi $ to the initial boundary value problem for the uniformly parabolic equation $ \ partial _ t \ varphi - \ mbox { div } ( a \ nabla \ varphi ) + \ omega \ varphi = f $ in $ \ omega _ t \ equiv \ omega \ times ( 0, t ) $ satisfies the uniform estimate $ $ \ | \ varphi \ | _ { \ infty, \ omega _ t } \ leq \ | \ varphi \ | _ { \ infty, \ partial _ p \ omega _ t } + c \ | f \ | _ { q, \ omega _ t }, \ \ \ c = c ( n, \ lambda, q, \ omega _ t ), $ $ provided that $ q > 1 + \ frac { n } { 2 } $, where $ \ omega $ is a bounded domain in $ \ mathbb { r } ^ n $ with lipschitz boundary, $ t > 0 $, $ \ partial _ p \ omega _ t $ is the parabolic boundary of $ \ omega _ t $, $ \ omega \ in l ^ 1 ( \ omega _ t ) $ with $ \ omega \ geq 0 $, and $ \ lambda $ is the smallest eigenvalue of the coefficient matrix $ a $. this estimate is sharp in the sense that it generally fails if $ q = 1 + \ frac { n } { 2 } $. in this paper we show that the linear growth of this upper bound in $ \ | f \ | _ { q, \ omega _ t } $ can be improved. to be precise, we establish \ begin { equation * } \ | \ varphi \ | _ { \ infty, \ omega _ t } \ leq \ | \ varphi _ 0 \ | _ { \ infty, \ partial _ p \ omega _ t } + c \ | f \ | _ { 1 + \ frac { n } { 2 }, \ omega _ t } \ left ( \ ln ( \ | f \ | _ { q, \ omega _ t } + 1 ) + 1 \ right ). \ end { equation * }
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arxiv:1711.01965
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accurate fading characterization and channel capacity determination are of paramount importance in both conventional and emerging communication systems. the present work addresses the nonlinearity of the propagation medium and its effects on the channel capacity. such fading conditions are first characterized using information theoretic measures, namely, shannon entropy, cross entropy and relative entropy. the corresponding effects on the channel capacity with and without power adaptation are then analyzed. closed - form expressions are derived and validated through comparisons with respective results from computer simulations. it is shown that the effects of fading nonlinearities are significantly larger than those of fading parameters such as the scattered - wave power ratio, and the correlation coefficient between the in - phase and quadrature components in each cluster of multipath components.
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arxiv:1507.08111
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we present a simple semi - perturbative argument in favour of a peculiar infrared behaviour of the ( singlet ) higgs propagator. on the basis of ` triviality ' one expects a continuum limit with a two - point function $ \ gamma _ 2 ( q ) \ to ( q ^ 2 + m ^ 2 _ h ) $. however, this is not valid in the limit $ q \ to 0 $ where one actually finds a singular behaviour. this is in agreement with both non - perturbative analyses of the effective potential and with lattice computations of the propagator and of the zero - momentum susceptibility in the broken phase. the singular behaviour persists in an o ( n ) continuous - symmetry theory, the case first pointed out by symanzik, and supports the existence of an extremely weak $ 1 / r $ potential that does not disappear when coupling the scalar fields to gauge bosons.
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arxiv:hep-ph/0003293
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a project engineer. chemical engineers serving as project engineers use their knowledge in selecting optimal production methods and plant equipment to minimize costs and maximize safety and profitability. after plant construction, chemical engineering project managers may be involved in equipment upgrades, troubleshooting, and daily operations in either full - time or consulting roles. = = see also = = = = = related topics = = = = = = related fields and concepts = = = = = = associations = = = = = references = = = = bibliography = =
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https://en.wikipedia.org/wiki/Chemical_engineering
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we have analyzed fuse observations of six hot white dwarf stars : four da white dwarfs with t _ eff > = 45000k, the dao feige55 ( t _ eff = 55000k ), and the da cd - 38 10980 ( t _ eff = 24000k ). photospheric lines from siiv, pv, and svi can be observed in the majority of the five hotter objects. feige55 shows also several other heavier elements. the measured abundances agree only partly with the predictions of the radiative levitation theory. we attribute this to current limitations of the models and the probable presence of mass loss. in the spectrum of cd - 38 10980, we have observed the quasi - molecular satellites of lbeta. this confirms theoretical predictions about the visibility range for these features.
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arxiv:astro-ph/0105024
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quantum thermodynamics addresses the emergence of thermodynamical laws from quantum mechanics. the link is based on the intimate connection of quantum thermodynamics with the theory of open quantum systems. quantum mechanics inserts dynamics into thermodynamics giving a sound foundation to finite - time - thermodynamics. the emergence of the 0 - law i - law ii - law and iii - law of thermodynamics from quantum considerations is presented. the emphasis is on consistence between the two theories which address the same subject from different foundations. we claim that inconsistency is the result of faulty analysis pointing to flaws in approximations.
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arxiv:1305.2268
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uncertain, unpredictable, real time, and lifelong evolution causes operational failures in intelligent software systems, leading to significant damages, safety and security hazards, and tragedies. to fully unleash the potential of such systems and facilitate their wider adoption, ensuring the trustworthiness of their decision making under uncertainty is the prime challenge. to overcome this challenge, an intelligent software system and its operating environment should be continuously monitored, tested, and refined during its lifetime operation. existing technologies, such as digital twins, can enable continuous synchronisation with such systems to reflect their most updated states. such representations are often in the form of prior knowledge based and machine learning models, together called model universe. in this paper, we present our vision of combining techniques from software engineering, evolutionary computation, and machine learning to support the model universe evolution.
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arxiv:2309.13342
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ai models make mistakes when recognizing images - whether in - domain, out - of - domain, or adversarial. predicting these errors is critical for improving system reliability, reducing costly mistakes, and enabling proactive corrections in real - world applications such as healthcare, finance, and autonomous systems. however, understanding what mistakes ai models make, why they occur, and how to predict them remains an open challenge. here, we conduct comprehensive empirical evaluations using a " mentor " model - a deep neural network designed to predict another " mentee " model ' s errors. our findings show that the mentor excels at learning from a mentee ' s mistakes on adversarial images with small perturbations and generalizes effectively to predict in - domain and out - of - domain errors of the mentee. additionally, transformer - based mentor models excel at predicting errors across various mentee architectures. subsequently, we draw insights from these observations and develop an " oracle " mentor model, dubbed supermentor, that can outperform baseline mentors in predicting errors across different error types from the imagenet - 1k dataset. our framework paves the way for future research on anticipating and correcting ai model behaviors, ultimately increasing trust in ai systems. all code, models, and data will be made publicly available.
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arxiv:2410.02384
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current ai - generated music lacks fundamental principles of good compositional techniques. by narrowing down implementation issues both programmatically and musically, we can create a better understanding of what parameters are necessary for a generated composition nearly indistinguishable from that of a master composer.
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arxiv:2101.00169
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we study the growth of harmonic functions on complete riemann - ian manifolds where the extrinsic diameter of geodesic spheres is sublinear. it is an generalization of a result of a. kazue. we also get a cheng and yau estimates for the gradient of harmonic functions.
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arxiv:1503.05506
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an operad ( this paper deals with non - symmetric operads ) may be conceived as a partial algebra with a family of insertion operations, gerstenhaber ' s circle - i products, which satisfy two kinds of associativity, one of them involving commutativity. a cat - operad is an operad enriched over the category cat of small categories, as a 2 - category with small hom - categories is a category enriched over cat. the notion of weak cat - operad is to the notion of cat - operad what the notion of bicategory is to the notion of 2 - category. the equations of operads like associativity of insertions are replaced by isomorphisms in a category. the goal of this paper is to formulate conditions concerning these isomorphisms that ensure coherence, in the sense that all diagrams of canonical arrows commute. this is the sense in which the notions of monoidal category and bicategory are coherent. the coherence proof in the paper is much simplified by indexing the insertion operations in a context - independent way, and not in the usual manner. this proof, which is in the style of term rewriting, involves an argument with normal forms that generalizes what is established with the completeness proof for the standard presentation of symmetric groups. this generalization may be of an independent interest, and related to matters other than those studied in this paper. some of the coherence conditions for weak cat - operads lead to the hemiassociahedron, which is a polyhedron related to, but different from, the three - dimensional associahedron and permutohedron.
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arxiv:1005.4633
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we prove lower bounds for higher - order methods in smooth non - convex finite - sum optimization. our contribution is threefold : we first show that a deterministic algorithm cannot profit from the finite - sum structure of the objective, and that simulating a pth - order regularized method on the whole function by constructing exact gradient information is optimal up to constant factors. we further show lower bounds for randomized algorithms and compare them with the best known upper bounds. to address some gaps between the bounds, we propose a new second - order smoothness assumption that can be seen as an analogue of the first - order mean - squared smoothness assumption. we prove that it is sufficient to ensure state - of - the - art convergence guarantees, while allowing for a sharper lower bound.
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arxiv:2103.05138
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" norms " which characterize real science. if any of the norms were violated, merton considered the enterprise to be non - science. his norms were : originality : the tests and research done must present something new to the scientific community. detachment : the scientists ' reasons for practicing this science must be simply for the expansion of their knowledge. the scientists should not have personal reasons to expect certain results. universality : no person should be able to more easily obtain the information of a test than another person. social class, religion, ethnicity, or any other personal factors should not be factors in someone ' s ability to receive or perform a type of science. skepticism : scientific facts must not be based on faith. one should always question every case and argument and constantly check for errors or invalid claims. public accessibility : any scientific knowledge one obtains should be made available to everyone. the results of any research should be published and shared with the scientific community. = = = refusal to acknowledge problems = = = in 1978, paul thagard proposed that pseudoscience is primarily distinguishable from science when it is less progressive than alternative theories over a long period of time, and its proponents fail to acknowledge or address problems with the theory. in 1983, mario bunge suggested the categories of " belief fields " and " research fields " to help distinguish between pseudoscience and science, where the former is primarily personal and subjective and the latter involves a certain systematic method. the 2018 book about scientific skepticism by steven novella, et al. the skeptics ' guide to the universe lists hostility to criticism as one of the major features of pseudoscience. = = = criticism of the term = = = larry laudan has suggested pseudoscience has no scientific meaning and is mostly used to describe human emotions : " if we would stand up and be counted on the side of reason, we ought to drop terms like ' pseudo - science ' and ' unscientific ' from our vocabulary ; they are just hollow phrases which do only emotive work for us ". likewise, richard mcnally states, " the term ' pseudoscience ' has become little more than an inflammatory buzzword for quickly dismissing one ' s opponents in media sound - bites " and " when therapeutic entrepreneurs make claims on behalf of their interventions, we should not waste our time trying to determine whether their interventions qualify as pseudoscientific. rather, we should ask them : how do you know that your intervention works? what is your evidence? " = = = alternative definition = = = for
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https://en.wikipedia.org/wiki/Pseudoscience
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we probed spin - spin correlations up to 725 k with 63cu nqr in the s = 1 / 2 three - leg ladder sr2cu3o5. we present experimental evidence that below 300 k, weak inter - ladder coupling causes dimensional crossover of the spin - spin correlation length \ xi from quasi - 1d ( \ xi ~ 1 / t ) to anisotropic 2d regime ( \ xi \ ~ exp [ 2 \ pi \ rho _ { s } / t ], where 2 \ pi \ rho _ { s } = 290 + / - 30 k is the effective spin stiffness ). this is the first experimental verification of the renormalized classical behavior of the anisotropic non - linear sigma model in 2d, which has been recently proposed for the striped phase in high t _ { c } cuprates.
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arxiv:cond-mat/9906141
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pegasus iii ( peg iii ) is one of the few known ultra - faint stellar systems in the outer halo of the milky way. we present the results from a follow - up campaign with magellan / imacs and keck / deimos. deep stellar photometry down to $ r _ 0 \ approx 25 $ mag at 50 % completeness level has allowed accurate measurements of its photometric and structural properties. the color - magnitude diagram of peg iii confirms that the stellar system is well described by an old ( $ \ gtrsim12 $ gyr ) and metal - poor ( [ fe / h ] $ \ lesssim - 2. 0 $ dex ) stellar population at a heliocentric distance of $ 215 \ pm12 $ kpc. the revised half - light radius $ r _ { h } = 53 \ pm14 $ pc, ellipticity $ \ epsilon = 0. 38 ^ { + 0. 22 } _ { - 0. 38 } $, and total luminosity $ m _ { v } = - 3. 4 \ pm0. 4 $ are in good agreement with the values quoted in our previous paper. we further report on the spectroscopic identification of seven, possibly eight member stars of peg iii. the ca ii triplet lines of the brightest member stars indicate that peg iii contains stars with metallicity as low as [ fe / h ] = $ - 2. 55 \ pm0. 15 $ dex. peg iii has a systemic velocity of $ - 222. 9 \ pm 2. 6 $ km s $ ^ { - 1 } $ and a velocity dispersion of $ 5. 4 ^ { + 3. 0 } _ { - 2. 5 } $ km s $ ^ { - 1 } $. the inferred dynamical mass within the half - light radius is $ 1. 4 ^ { + 3. 0 } _ { - 1. 1 } \ times 10 ^ 6 \ rm { m _ { \ odot } } $ and the mass - to - light ratio $ \ rm { m / l } $ $ _ { v } = 1470 ^ { + 5660 } _ { - 1240 } $ $ \ rm { m _ { \ odot } / l _ { \ odot } } $, providing further evidence that peg iii is a dwarf galaxy satellite. we find that peg iii and another distant dwarf satellite pisces ii lie relatively close to each other ( $ \ delta d _ { spatial } = 43 \ pm
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arxiv:1608.04934
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we collect some recent results that together provide an almost complete answer to the question stated in the title. for the dimension d = 2 the answer is three. for the dimensions d = 3 and d > 4 the answer is four. for the dimension d = 4 the answer is either three or four. curiously, the exact number in d = 4 seems to be an open problem.
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arxiv:1504.01590
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ages are key to truly understand a large plethora of astrophysical phenomena. on the other hand, stellar clusters are open windows to understand stellar evolution, specifically, the change with time and mass of different stellar properties. as such, they are our laboratories where different theories can be tested, but without accurate ages, our knowledge would impaired. we revisit here a large number of age - dating techniques and discuss their advantages and draw - backs. in addition, a step - by step process is suggested in order to built a coherent age scale ladder, minimizing the error budget and the sources of uncertainty.
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arxiv:1606.09448
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in this paper, we give sharp rusak - and markov - type inequalities for rational functions on several intervals when the system of intervals is a \ textquotedblleft rational function inverse image \ textquotedblright \, of an interval and those functions are large in gaps.
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arxiv:1412.1644
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using two different methods, we have determined the rescaling of the scalar condensate $ z \ equiv z _ \ phi $ near the critical line of a 4d ising model. our lattice data, in agreement with previous numerical indications, support the behavior $ z _ \ phi \ sim \ ln ( { \ lambda } ) $, $ \ lambda $ being the ultraviolet cutoff. this result is predicted in an alternative description of symmetry breaking where there are no upper bounds on the higgs boson mass from ` triviality '.
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arxiv:hep-lat/0407024
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this paper explores the possibility that an exactly decoherent set of histories may be constructed from an approximately decoherent set by small distortions of the operators characterizing the histories. in particular, for the case of histories of positions and momenta, this is achieved by doubling the set of operators and then finding, amongst this enlarged set, new position and momentum operators which commute, so decohere exactly, and which are ` ` close ' ' to the original operators. the enlarged, exactly decoherent, theory has the same classical dynamics as the original one, and coincides with the so - called deterministic quantum theories of the type recently studied by ' t hooft. these results suggest that the comparison of standard and deterministic quantum theories may provide an alternative method of characterizing emergent classicality. a side - product is the surprising result that histories of momenta in the quantum brownian motion model ( for the free particle in the high - temperature limit ) are exactly decoherent.
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arxiv:quant-ph/0011103
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when light and matter interact strongly, the resulting hybrid system inherits properties from both constituents, allowing one to modify material behavior by engineering the surrounding electromagnetic environment. this concept underlies the emerging paradigm of cavity materials engineering, which aims at the control of material properties via tailored vacuum fluctuations of dark photonic environments. the theoretical description of such systems is challenging due to the combined complexity of extended electronic states and quantum electromagnetic fields. here, we derive an effective, non - perturbative theory for low - dimensional crystals embedded in a fabry - p \ ' erot resonator, within the long - wavelength limit. our approach incorporates the multimode and dispersive nature of the cavity field and reduces it to an effective single - mode description by imposing the condition of negligible momentum transfer from light to matter. importantly, the resulting effective mode is characterized by a finite mode volume - even in the limit of extended cavities - which is directly linked to realistic cavity parameters. this ensures that the light - matter coupling remains finite in bulk systems. by explicitly accounting for the finite reflectivity of cavity mirrors, our theory also avoids double counting the contribution from free - space light - matter coupling. overall, our results provide a robust and realistic framework for describing cavity - matter interactions at the hamiltonian level, incorporating the electromagnetic environment beyond the idealized perfect - mirror approximation.
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arxiv:2312.17374
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some new directions to lay a rigorous mathematical foundation for the phase - portrait - based modelling of fingerprints are discussed in the present work. couched in the language of dynamical systems, and preparing to a preliminary modelling, a back - to - basics analogy between poincar \ ' { e } ' s categories of equilibria of planar differential systems and the basic fingerprint singularities according to purkyn \ v { e } - galton ' s standards is first investigated. then, the problem of the global representation of a fingerprint ' s flow - like pattern as a smooth deformation of the phase portrait of a differential system is addressed. unlike visualisation in fluid dynamics, where similarity between integral curves of smooth vector fields and flow streamline patterns is eye - catching, the case of an oriented texture like a fingerprint ' s stream of ridges proved to be a hard problem since, on the one hand, not all fingerprint singularities and nearby orientational behaviour can be modelled by canonical phase portraits on the plane, and on the other hand, even if it were the case, this should lead to a perplexing geometrical problem of connecting local phase portraits, a question which will be formulated within poincar \ ' { e } ' s index theory and addressed via a normal form approach as a bivariate hermite interpolation problem. to a certain extent, the material presented herein is self - contained and provides a baseline for future work where, starting from a normal form as a source image, a transport via large deformation flows is envisaged to match the fingerprint as a target image.
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arxiv:1802.05671
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we present an su ( 4 ) model of high - $ t _ c $ superconductivity. one dynamical symmetry of this model corresponds to the previously proposed so ( 5 ) model for unification of superconductivity and antiferromagnetism, but there are two additional dynamical symmetries : so ( 4 ), associated with antiferromagnetic order and su ( 2 ), associated with a d - wave pairing condensate. these provide a 3 - phase microscopic model of high - $ t _ c $ superconductivity and permit a clear understanding of the role played by the so ( 5 ) symmetry.
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arxiv:cond-mat/9903150
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let h be the n - dimensional hyperbolic space of constant sectional curvature - 1 and let g be the identity component of the isometry group of h. we find all the g - invariant pseudo - riemannian metrics on the space og _ n of oriented geodesics of h ( modulo orientation preserving reparametrizations ). we characterize the null, time - and space - like curves, providing a relationship between the geometries of og _ n and h. moreover, we show that og _ 3 is k \ " { a } hler and find an orthogonal almost complex structure on og _ 7.
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arxiv:math/0702365
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let $ \ mathsf { x } $ be the product of a complex projective space and a polydisc. we study poisson brackets on $ \ mathsf { x } $ that are log symplectic, that is, generically symplectic and such that the inverse two - form has only first order poles. we propose a method of constructing such poisson brackets that additionally are elliptic, in a precise sense. our method relies on the local torelli theorem for log symplectic manifolds of pym, schedler and the author, and uses combinatorics of smoothing diagrams. we demonstrate effectiveness of the method on a series of examples, recovering, in particular, all log symplectic cases of elliptic feigin - odesskii poisson brackets $ q _ { n, k } $ on $ \ mathbb { p } ^ { n - 1 } $.
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arxiv:2310.05284
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finding the ground - state energy of molecules is an important and challenging computational problem for which quantum computing can potentially find efficient solutions. the variational quantum eigensolver ( vqe ) is a quantum algorithm that tackles the molecular groundstate problem and is regarded as one of the flagships of quantum computing. yet, to date, only very small molecules were computed via vqe, due to high noise levels in current quantum devices. here we present an alternative variational quantum scheme that requires significantly less qubits. the reduction in qubit number allows for shallower circuits to be sufficient, rendering the method more resistant to noise. the proposed algorithm, termed variational quantum selected - configuration - interaction ( vq - sci ), is based on : ( a ) representing the target groundstate as a superposition of slater determinant configurations, encoded directly upon the quantum computational basis states ; and ( b ) selecting a - priory only the most dominant configurations. this is demonstrated through a set of groundstate calculations of the h $ _ 2 $, lih, beh $ _ 2 $, h $ _ 2 $ o, nh $ _ 3 $ and c $ _ 2 $ h $ _ 4 $ molecules in the sto - 3g basis set, performed on ibm quantum devices. we show that the vq - sci reaches the full - ci ( fci ) energy within chemical accuracy using the lowest number of qubits reported to date. moreover, when the sci matrix is generated ` ` on the fly ", the vq - sci requires exponentially less memory than classical sci methods. this offers a potential remedy to a severe memory bottleneck problem in classical sci calculations. finally, the proposed scheme is general and can be straightforwardly applied for finding the groundstate of any hermitian matrix, outside the chemical context.
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arxiv:2302.06691
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the processes regulating protoplanetary disk evolution are constrained by studying how mass accretion rates scale with stellar and disk properties. the spread in these relations can be used as a constraint to the models of disk evolution, but only if the impact of accretion variability is correctly accounted for. while the effect of variability might be substantial in the embedded phases of star formation, it is often considered limited at later stages. here we report on the observed large variation in the accretion rate for one target, xx cha, and we discuss the impact on population studies of classical t tauri stars. the mass accretion rate determined by fitting the uv - to - near - infrared spectrum in recent x - shooter observations is compared with the one measured with the same instrument 11 years before. xx cha displays an accretion variability of almost 2 dex between 2010 and 2021. although the timescales on which this variability happens are uncertain, xx cha displays an extreme accretion variability for a classical t tauri star. if such behavior is common among classical t tauri stars, possibly on longer timescales than previously probed, it could be relevant for discussing the disk evolution models constrained by the observed spread in accretion rates. finally, we remark that previous studies of accretion variability based on spectral lines may have underestimated the variability of some targets.
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arxiv:2208.01447
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we consider three one - dimensional continuous - time markov processes on a lattice, each of which models the conduction of heat : the family of brownian energy processes with parameter $ m $, a generalized brownian energy process, and the kipnis - marchioro - presutti process. the hydrodynamic limit of each of these three processes is a parabolic equation, the linear heat equation in the case of the bep $ ( m ) $ and the kmp, and a nonlinear heat equation for the gbep ( $ a $ ). we prove the hydrodynamic limit rigorously for the bep $ ( m ) $, and give a formal derivation for the gbep ( $ a $ ). we then formally derive the pathwise large - deviation rate functional for the empirical measure of the three processes. these rate functionals imply gradient - flow structures for the limiting linear and nonlinear heat equations. we contrast these gradient - flow structures with those for processes describing the diffusion of mass, most importantly the class of wasserstein gradient - flow systems. the linear and nonlinear heat - equation gradient - flow structures are each driven by entropy terms of the form $ - \ log \ rho $ ; they involve dissipation or mobility terms of order $ \ rho ^ 2 $ for the linear heat equation, and a nonlinear function of $ \ rho $ for the nonlinear heat equation.
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arxiv:1403.4994
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decolorization is the process to convert a color image or video to its grayscale version, and it has received great attention in recent years. an ideal decolorization algorithm should preserve the original color contrast as much as possible. meanwhile, it should provide the final decolorized result as fast as possible. however, most of the current methods are suffering from either unsatisfied color information preservation or high computational cost, limiting their application value. in this paper, a simple but effective technique is proposed for real - time decolorization. based on the typical rgb2gray ( ) color conversion model, which produces a grayscale image by linearly combining r, g, and b channels, we propose a dominant color hypothesis and a corresponding distance measurement metric to evaluate the quality of grayscale conversion. the local optimum scheme provides several " good " candidates in a confidence interval, from which the " best " result can be extracted. experimental results demonstrate that remarkable simplicity of the proposed method facilitates the process of high resolution images and videos in real - time using a common cpu.
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arxiv:1404.2728
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software has eaten the world with many of the necessities and quality of life services people use requiring software. therefore, tools that improve the software development experience can have a significant impact on the world such as generating code and test cases, detecting bugs, question and answering, etc., the success of deep learning ( dl ) over the past decade has shown huge advancements in automation across many domains, including software development processes. one of the main reasons behind this success is the availability of large datasets such as open - source code available through github or image datasets of mobile graphical user interfaces ( guis ) with rico and redraw to be trained on. therefore, the central research question my dissertation explores is : in what ways can the software development process be improved through leveraging dl techniques on the vast amounts of unstructured software engineering artifacts?
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arxiv:2310.10921
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the reconstruction of the unknown acoustic source is studied using the noisy multiple frequency data on a remote closed surface. assume that the unknown source is coded in a spatial dependent piecewise constant function, whose support set is the target to be determined. in this setting, the unknown source can be formalized by a level set function. the function is explored with bayesian level set approach. to reduce the infinite dimensional problem to finite dimension, we parameterize the level set function by the radial basis expansion. the well - posedness of the posterior distribution is proven. the posterior samples are generated according to the metropolis - hastings algorithm and the sample mean is used to approximate the unknown. several shapes are tested to verify the effectiveness of the proposed algorithm. these numerical results show that the proposed algorithm is feasible and competitive with the mat \ ' ern random field for the acoustic source problem.
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arxiv:1907.08660
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the recent years have seen remarkable progress in establishing the complexity of the reachability problem for vector addition systems with states ( vass ), equivalently known as petri nets. existing work primarily considers the case in which both the vass as well as the initial and target configurations are part of the input. in this paper, we investigate the reachability problem in the setting where the vass is fixed and only the initial configuration is variable. we show that fixed vass fully express arithmetic on initial segments of the natural numbers. it follows that there is a very weak reduction from any fixed such number - theoretic predicate ( e. g. primality or square - freeness ) to reachability in fixed vass where configurations are presented in unary. if configurations are given in binary, we show that there is a fixed vass with five counters whose reachability problem is pspace - hard.
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arxiv:2310.16740
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we point out that protoplanets created in the framework of the tidal downsizing ( td ) theory for planet formation play a very important role for the evolution of accretion discs hosting them. since all td protoplanets are initially as massive as $ \ sim 10 $ jupiter masses, they are able to open very deep gaps in their discs, and even completely isolate the inner disc flows from the outer ones. furthermore, in contrast to other planet formation theories, td protoplanets are mass donors for their protostars. one potentially observable signature of planets being devoured by their protostars are fu ori like outbursts, and episodic protostar accretion more generally, as discussed by a number of authors recently. here we explore another observational implication of td hypothesis : dust poor inner accretion flows, which we believe may be relevant to some of the observed mm - bright transitional discs around protostars. in our model, a massive protoplanet interrupts the flow of the outer dust - rich disc on its protostar, and at the same time looses a part of its dust - poor envelope into the inner disc. this then powers the observed gas - but - no - dust accretion onto the star. upon a more detailed investigation, we find that this scenario is quite natural for young massive discs but is less so for older discs, e. g., those whose self - gravitating phase has terminated a fraction of a million year or more ago. this stems from the fact that td protoplanets of such an age should have contracted significantly, and so are unlikely to loose much mass. therefore, we conclude that either ( i ) the population of " transition discs " with large holes and dust - poor accretion is much younger than generally believed ; or ( ii ) there is a poorly understood stage for late removal of dust - poor envelopes from td planets ; ( iii ) another explanation for the observations is correct.
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arxiv:1302.1389
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we consider the production of heavy quark jets at the $ z $ - pole at the next - to - leading order ( nlo ) using the { \ it cambridge jet - algorithm }. we study the effects of the quark mass in two - and three - jet observables and the uncertainty due to unknown higher order corrections as well as due to fragmentation. we found that the three - jet observable has remarkably small nlo corrections, which are stable with respect to the change of the renormalization scale, when expressed in terms of the { \ it running quark mass } at the $ m _ z $ - scale. the size of the hadronization uncertainty for this observable remains reasonably small and is very stable with respect to changes in the jet resolution parameter $ y _ c $.
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arxiv:hep-ph/9807489
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the observed upper bound on the spin down rate of the otherwise typical soft gamma - ray repeater sgr 0418 + 5729 has challenged the interpretation of this source as a neutron star with ultrastrong magnetic fields. current limits imply a dipole magnetic field strength of less than 7. 5 x 10 ^ { 12 } g ( rea et al. 2010 ), which is significantly smaller than that of a typical sgr. independent of the properties inferred from x - ray timing, the x - ray spectra of neutron stars allow a measurement of their magnetic field strengths because they are distorted from pure blackbodies due to the presence of a magnetic field in a radiative equilibrium atmosphere. in this paper, we model high signal - to - noise xmm - newton spectra of sgr 0418 + 5729 to place constraints on the strength of the magnetic field at the surface of the neutron star. our analysis shows that neutron star atmosphere models with moderate magnetic field strengths ( 10 ^ { 12 - 13 } g ) cannot fit the x - ray spectra, whereas, models with stronger magnetic fields are able to account for the observations. we find that the strength of the magnetic field at the surface is 1. 0 x 10 ^ { 14 } g. this value, although lower than all of the other sgrs analyzed to date, is still high enough to generate the observed x - ray bursts from the source. in connection to the spindown limits, it also implies a significantly non - dipolar structure of the magnetic field. we discuss the results of our spectral modeling and compare them with other sgrs.
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arxiv:1103.3024
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as for human avatar reconstruction, contemporary techniques commonly necessitate the acquisition of costly data and struggle to achieve satisfactory results from a small number of casual images. in this paper, we investigate this task from a few - shot unconstrained photo album. the reconstruction of human avatars from such data sources is challenging because of limited data amount and dynamic articulated poses. for handling dynamic data, we integrate a skinning mechanism with deep marching tetrahedra ( dmtet ) to form a drivable tetrahedral representation, which drives arbitrary mesh topologies generated by the dmtet for the adaptation of unconstrained images. to effectively mine instructive information from few - shot data, we devise a two - phase optimization method with few - shot reference and few - shot guidance. the former focuses on aligning avatar identity with reference images, while the latter aims to generate plausible appearances for unseen regions. overall, our framework, called havefun, can undertake avatar reconstruction, rendering, and animation. extensive experiments on our developed benchmarks demonstrate that havefun exhibits substantially superior performance in reconstructing the human body and hand. project website : https : / / seanchenxy. github. io / havefunweb /.
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arxiv:2311.15672
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news articles typically mention numerous entities, a large fraction of which are tangential to the story. detecting the salience of entities in articles is thus important to applications such as news search, analysis and summarization. in this work, we explore new approaches for efficient and effective salient entity detection by fine - tuning pretrained transformer models with classification heads that use entity tags or contextualized entity representations directly. experiments show that these straightforward techniques dramatically outperform prior work across datasets with varying sizes and salience definitions. we also study knowledge distillation techniques to effectively reduce the computational cost of these models without affecting their accuracy. finally, we conduct extensive analyses and ablation experiments to characterize the behavior of the proposed models.
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arxiv:2405.20461
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the neural network needs excessive costs of time because of the complexity of architecture when trained on images. transfer learning and fine - tuning can help improve time and cost efficiency when training a neural network. yet, transfer learning and fine - tuning needs a lot of experiment to try with. therefore, a method to find the best architecture for transfer learning and fine - tuning is needed. to overcome this problem, neuro - evolution using a genetic algorithm can be used to find the best architecture for transfer learning. to check the performance of this study, dataset chestx - ray 14 and densenet - 121 as a base neural network model are used. this study used the auc score, differences in execution time for training, and mcnemar ' s test to the significance test. in terms of result, this study got a 5 % difference in the auc score, 3 % faster in terms of execution time, and significance in most of the disease detection. finally, this study gives a concrete summary of how neuro - evolution transfer learning can help in terms of transfer learning and fine - tuning.
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arxiv:2004.07136
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in this note we describe a relation between euler ' s elasticae and sub - riemannian geodesics on se ( 2 ). analyzing the hamiltonian system of pontryagin maximum principle we show that these two curves coincide only in the case when they are segments of a straight line.
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arxiv:1609.03704
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in the last years the possibility of creating and manipulating quantum states of light has paved the way to the development of new technologies exploiting peculiar properties of quantum states, as quantum information, quantum metrology & sensing, quantum imaging... in particular quantum imaging addresses the possibility of overcoming limits of classical optics by using quantum resources as entanglement or sub - poissonian statistics. albeit quantum imaging is a more recent field than other quantum technologies, e. g. quantum information, it is now substantially mature for application. several different protocols have been proposed, some of them only theoretically, others with an experimental implementation and a few of them pointing to a clear application. here we present a few of the most mature protocols ranging from ghost imaging to sub shot noise imaging and sub rayleigh imaging.
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arxiv:1601.06066
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the basis of the so - called zenon effect in quantum mechanics, is the limiting behavior of the unitary solution of schroedinger ' s equation, under repeated measurments. we examine the limit of a sequence of operators complosed by a usual operator and a projection operator.
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arxiv:0906.0830
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serverless computing provides fine - grain resource sharing between cloud tenants through containers. each function invocation ( action ) runs in an individual container. when there is not an already started container for a user function, a new container has to be created for it. however, the long cold startup time of a container results in the long response latency of the action. our investigation shows that the containers for some user actions share most of the software packages. if an action that requires a new container can ` ` borrow ' ' a similar warm container from other actions, the long cold startup can be eliminated. based on the above finding, we propose pagurus, a runtime container management system for eliminating the cold startup in serverless computing. pagurus is comprised of an inter - action container scheduler and an intra - action container scheduler for each action. the inter - action container scheduler schedules shared containers among actions. the intra - action container scheduler deals with the management of the container lifecycle. our experimental results show that pagurus effectively eliminates the time - consuming container cold startup. an action may start to run in 10ms with pagurus, even if there is not warm container for it.
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arxiv:2108.11240
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we study integrable deformations of sine - liouville conformal field theory. every integrable perturbation of this model is related to the series of quantum integrals of motion ( hierarchy ). we construct the factorized scattering matrices for different integrable perturbed conformal field theories. the perturbation theory, bethe ansatz technique, renormalization group and methods of perturbed conformal field theory are applied to show that all integrable deformations of sine - liouville model possess non - trivial duality properties.
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arxiv:1705.06424
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noncommutative geometry provides both a unified description of the standard model of particle physics together with einstein - hilbert action ( in euclidean signature ) and some tools to go beyond the standard model. in this paper, we extend to the full noncommutative geometry of the standard model the twist ( in the sense of connes - moscovici ) initially worked out for the electroweak sector and the free dirac operator only. namely, we apply the twist also to the strong interaction sector and the finite part of the dirac operator. to do so, we are forced to take into account a violation of the twisted first - order condition. as a result, we still obtain the extra scalar field required to stabilise the electroweak vacuum and fit the higgs mass, but it now has two chiral components. we also get the additive field of 1 - forms already pointed out in the electroweak model, but with a richer structure. finally, we obtain a pair of higgs doublets, which are expected to combine into a single higgs doublet in the action formula, as will be investigated in the second part of this work.
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arxiv:2008.01629
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we investigate under which conditions the three - dimensional ( 3d ) multicomponent abelian - higgs ( ah ) field theory ( scalar electrodynamics ) is the continuum limit of statistical lattice gauge models, i. e., when it characterizes the universal behavior at critical transitions occurring in these models. we perform monte carlo simulations of the lattice ah model with compact gauge fields and $ n $ - component scalar fields with charge $ q \ ge 2 $ for $ n = 15 $ and 25. finite - size scaling analyses of the monte carlo data show that the transitions along the line separating the confined and deconfined phases are continuous and that they belong to the same universality class for any $ q \ ge 2 $. moreover, they are in the same universality class as the transitions in the lattice ah model with noncompact gauge fields along the coulomb - to - higgs transition line. we finally argue that these critical behaviors are described by the stable charged fixed point of the renormalization - group flow of the 3d ah field theory.
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arxiv:2201.01082
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let $ \ gamma = \ langle a, b | a b ^ { p } a ^ { - 1 } = b ^ { q } \ rangle $ be a baumslag - - solitar group and $ g $ be a complex reductive algebraic group with maximal compact subgroup $ k < g $. we show that, when $ p $ and $ q $ are relatively prime with distinct absolute values, there is a strong deformation retraction retraction of $ hom ( \ gamma, g ) $ onto $ hom ( \ gamma, k ) $.
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arxiv:1902.04046
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in the unix / linux environment the kernel can log every command process created by every user using process accounting. this data has many potential uses, including the investigation of security incidents. however, process accounting data is also sensitive since it contains private user information. consequently, security system administrators have been hindered from sharing these logs. given that many interesting security applications could use process accounting data, it would be useful to have a tool that could protect private user information in the logs. for this reason we introduce scrub - pa, a tool that uses multi - level multi - dimensional anonymization on process accounting log files in order to provide different levels of privacy protection. it is our goal that scrub - pa will promote the sharing of process accounting logs while preserving privacy.
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arxiv:cs/0601079
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a new version of quantum hashing technique is developed wherein a quantum hash is constructed as a sequence of single - photon high - dimensional states ( qudits ). a proof - of - principle implementation of the high - dimensional quantum hashing protocol using orbital - angular momentum encoding of single photons is implemented. it is shown that the number of qudits decreases with increase of their dimension for an optimal ratio between collision probability and decoding probability of the hash. thus, increasing dimension of information carriers makes quantum hashing with single photons more efficient.
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arxiv:2210.10501
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the ability of bumblebee gravity models to explain dark energy, which is the phenomenon responsible for the universe ' s observed accelerated expansion, is one of their most significant applications. an effect that causes faster expansion can be linked to how much the lorentz symmetry of our universe is violated. moreover, since we do not know what generates dark energy, the bumblebee gravity theory seems highly plausible. by utilizing the physical changes happening around a rotating bumblebee black hole ( rbbh ), we aim to obtain more specific details about the bumblebee black hole ' s spacetime and our universe. however, as researched in the literature, slow - spinning rbbh ( srbbh ) spacetime, which has a higher accuracy, will be considered instead of general rbbh. to this end, we first employ the rindler - - ishak method ( rim ), which enables us to study how light is bent in the vicinity of a gravitational lens. we evaluate the deflection angle of null geodesics in the equatorial plane of the srbbh spacetime. then, we use astrophysical data to see the effect of the lorentz symmetry breaking ( lsb ) parameter on the bending angle of light for numerous astrophysical stars and black holes. we also acquire the analytical greybody factors ( gfs ) and quasinormal modes ( qnms ) of the srbbh. finally, we visualize and discuss the results obtained in the conclusion section.
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arxiv:2305.10815
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a notion of curvature is introduced in multivariable operator theory and an analogue of the gauss - bonnet - chern theorem is established for graded ( contractive ) hilbert modules over the complex polynomial algebra in d variables, d = 1, 2, 3,.... the curvature invariant, euler characteristic, and degree are computed for some explicit examples based on varieties in ( multidimensional ) complex projective space, and applications are given to the structure of graded ideals in c [ z _ 1,..., z _ d ] and to the existence of " inner sequences " for closed submodules of the free hilbert module h ^ 2 ( c ^ d ).
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arxiv:math/9808100
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grs 1915 + 105, one of the two known galactic microquasars, shows an extremely complex variability in the x - ray band, comparable to no other x - ray source in the sky. making use of rxte / pca data, we have analyzed the x - ray spectral distribution throughout the variability. we find that all variations can be attributed to the rapid appearance and disappearance of the inner region of an optically - thick accretion disk. since the time scale for each event is related to the maximum radius of the disappearing region, the difference in time structure is due to the time distribution of such radii. the observed relation between the extent of the missing inner region of the disk and the duration of an event is in remarkable agreement with the expected radius dependence of the viscous time scale of the radiation - dominated region of an accretion disk.
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arxiv:astro-ph/9712232
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this article is devoted to the investigation of structure of wrap groups of connected fiber bundles over the fields of real $ \ bf r $, complex $ \ bf c $ numbers, the quaternion skew field $ \ bf h $ and the octonion algebra $ \ bf o $. iterated wrap groups are studied as well. their smashed products are constructed.
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arxiv:0804.4286
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we explicate a procedure to solve general linear differential equations, which connects the desired solutions to monomials x ^ m of an appropriate degree m. in the process the underlying symmetry of the equations under study, as well as that of the solutions are made transparent. we demonstrate the efficacy of the method by showing the common structure of the solution space of a wide variety of differential equations viz. hermite, laguerre, jocobi, bessel and hypergeometric etc. we also illustrate the use of the procedure to develop approximate solutions, as well as in finding solutions of many particle interacting systems.
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arxiv:1205.0385
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the " eternal war in cache " has reached browsers, with multiple cache - based side - channel attacks and countermeasures being suggested. a common approach for countermeasures is to disable or restrict javascript features deemed essential for carrying out attacks. to assess the effectiveness of this approach, in this work we seek to identify those javascript features which are essential for carrying out a cache - based attack. we develop a sequence of attacks with progressively decreasing dependency on javascript features, culminating in the first browser - based side - channel attack which is constructed entirely from cascading style sheets ( css ) and html, and works even when script execution is completely blocked. we then show that avoiding javascript features makes our techniques architecturally agnostic, resulting in microarchitectural website fingerprinting attacks that work across hardware platforms including intel core, amd ryzen, samsung exynos, and apple m1 architectures. as a final contribution, we evaluate our techniques in hardened browser environments including the tor browser, deter - fox ( cao el al., ccs 2017 ), and chrome zero ( schwartz et al., ndss 2018 ). we confirm that none of these approaches completely defend against our attacks. we further argue that the protections of chrome zero need to be more comprehensively applied, and that the performance and user experience of chrome zero will be severely degraded if this approach is taken.
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arxiv:2103.04952
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resource - aware type systems statically approximate not only the expected result type of a program, but also the way external resources are used, e. g., how many times the value of a variable is needed. we extend the type system of featherweight java to be resource - aware, parametrically on an arbitrary grade algebra modeling a specific usage of resources. we prove that this type system is sound with respect to a resource - aware version of reduction, that is, a well - typed program has a reduction sequence which does not get stuck due to resource consumption. moreover, we show that the available grades can be heterogeneous, that is, obtained by combining grades of different kinds, via a minimal collection of homomorphisms from one kind to another. finally, we show how grade algebras and homomorphisms can be specified as java classes, so that grade annotations in types can be written in the language itself.
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arxiv:2302.07782
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##vable in order to discriminate a viable de model among a slew of models which are degenerated in cmb. also we obtain the lower limit on w0 > - 1. 5 from the cmb acoustic peaks and this will provide the useful limitation on phantom models.
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arxiv:1409.1355
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known simulations of random access machines ( rams ) or parallel rams ( prams ) by boolean circuits incur significant polynomial blowup, due to the need to repeatedly simulate accesses to a large main memory. consider a single modification to boolean circuits that removes the restriction that circuit graphs are acyclic. we call this the cyclic circuit model. note, cyclic circuits remain combinational, as they do not allow wire values to change over time. we simulate pram with a cyclic circuit, and the blowup from our simulation is only polylogarithmic. consider a pram program $ p $ that on a length - $ n $ input uses an arbitrary number of processors to manipulate words of size $ \ theta ( \ log n ) $ bits and then halts within $ w ( n ) $ work. we construct a size - $ o ( w ( n ) \ cdot \ log ^ 4 n ) $ cyclic circuit that simulates $ p $. suppose that on a particular input, $ p $ halts in time $ t $ ; our circuit computes the same output within $ t \ cdot o ( \ log ^ 3 n ) $ gate delay. this implies theoretical feasibility of powerful parallel machines. cyclic circuits can be implemented in hardware, and our circuit achieves performance within polylog factors of pram. our simulated pram synchronizes processors via logical dependencies between wires.
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arxiv:2309.05133
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in this paper, we characterize the ( generalized ) frobenius powers and critical exponents of two classes of monomial ideals of a polynomial ring in positive characteristic : powers of the homogeneous maximal ideal, and ideals generated by positive powers of the variables. in doing so, we effectively characterize the test ideals and $ f $ - jumping exponents of sufficiently general homogeneous polynomials, and of all diagonal polynomials. our characterizations make these invariants computable, and show that they vary uniformly with the congruence class of the characteristic modulo a fixed integer. moreover, we confirm that for a diagonal polynomial over a field of characteristic zero, the test ideals of its reduction modulo a prime agree with the reductions of its multiplier ideals for infinitely many primes.
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arxiv:1808.09508
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the structural degrees of freedom of a material are the various distortions most straightforwardly activated by external stimuli. a highly successful design strategy in materials chemistry involves controlling these individual distortions to produce useful functional responses. in a ferroelectric such as lead titanate, for example, the key degree of freedom involves displacements of pb $ ^ { 2 + } $ ; by coupling these together, the system interacts with electric fields. an exciting development has been to exploit the interplay between different distortions : $ e. g. $ generating polarisation by combining different polyhedral rotations. thus, degrees of freedom act as geometric ` elements ' that can be combined to engineer materials with interesting properties. just as the discovery of new elements diversified chemical space, identifying new types of structural degrees of freedom is a key strategy for developing new functional materials. in this context, molecular frameworks are a fertile source of unanticipated distortion types, many of which have no parallel in conventional solid - state chemistry. framework materials are solids whose structures are assembled from nodes and linkers to form scaffolding - like networks. these structures usually contain cavities, which may host additional ions for charge balance. in the well - established systems - - - such as lead titanate - - - these components are all atomic, but in molecular frameworks, at least one ion is molecular. here, we survey the unconventional degrees of freedom introduced through the replacement of atoms by molecules. our motivation is to understand the role these new distortions play in different materials properties. the various degrees of freedom are summarised and described in the context of experimental examples. we highlight a number of directions for future research, which demonstrate the extraordinary possibilities for this nascent field.
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arxiv:2011.13765
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to be a poetic and allegorical work rather than a literal history, and many christian churches — including the eastern orthodox church, the roman catholic, anglican and the more liberal denominations of the lutheran, methodist, congregationalist and presbyterian faiths — have either rejected creation science outright or are ambivalent to it. belief in non - literal interpretations of genesis is often cited as going back to saint augustine. theistic evolution and evolutionary creationism are theologies that reconcile belief in a creator with biological evolution. each holds the view that there is a creator but that this creator has employed the natural force of evolution to unfold a divine plan. religious representatives from faiths compatible with theistic evolution and evolutionary creationism have challenged the growing perception that belief in a creator is inconsistent with the acceptance of evolutionary theory. spokespersons from the catholic church have specifically criticized biblical creationism for relying upon literal interpretations of biblical scripture as the basis for determining scientific fact. = = = scientific criticism = = = the national academy of sciences states that " the claims of creation science lack empirical support and cannot be meaningfully tested " and that " creation science is in fact not science and should not be presented as such in science classes. " according to joyce arthur writing for skeptic magazine, the " creation ' science ' movement gains much of its strength through the use of distortion and scientifically unethical tactics " and " seriously misrepresents the theory of evolution. " scientists have considered the hypotheses proposed by creation science and have rejected them because of a lack of evidence. furthermore, the claims of creation science do not refer to natural causes and cannot be subject to meaningful tests, so they do not qualify as scientific hypotheses. in 1987, the united states supreme court ruled that creationism is religion, not science, and cannot be advocated in public school classrooms. most mainline christian denominations have concluded that the concept of evolution is not at odds with their descriptions of creation and human origins. a summary of the objections to creation science by scientists follows : creation science is not falsifiable : an idea or hypothesis is generally not considered to be in the realm of science unless it can be potentially disproved with certain experiments, this is the concept of falsifiability in science. the act of creation as defined in creation science is not falsifiable because no testable bounds can be imposed on the creator. in creation science, the creator is defined as limitless, with the capacity to create ( or not ), through fiat alone, infinite
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https://en.wikipedia.org/wiki/Creation_science
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in this work, we consider an inhomogeneous ( discrete time ) markov chain and are interested in its long time behavior. we provide sufficient conditions to ensure that some of its asymptotic properties can be related to the ones of a homogeneous ( continuous time ) markov process. renowned examples such as a bandit algorithms, weighted random walks or decreasing step euler schemes are included in our framework. our results are related to functional limit theorems, but the approach differs from the standard " tightness / identification " argument ; our method is unified and based on the notion of pseudotrajectories on the space of probability measures.
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arxiv:1601.06266
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the main focus of this article is the study of ergodicity of interacting particle systems ( ips ). we present a simple lemma showing that scaling time is equivalent to taking the convex combination of the transition matrix of the ips with the identity. as a consequence, the ergodic properties of ips are invariant under this transformation. surprisingly, this simple observation has non - trivial implications : it allows to extend any result that does not respect this invariance, which we demonstrate with examples. additionally, we develop a recursive method to deduce decay of correlations for ips with alphabets of arbitrary ( finite ) size, and apply the time - scaling lemma to that as well. as an application of this new criterion we show that certain one - dimensional ips are ergodic answering an open question of toom et al..
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arxiv:2312.06935
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in a previous study, we presented vt - lane, a three - step framework for real - time vehicle detection, tracking, and turn movement classification at urban intersections. in this study, we present a case study incorporating the highly accurate trajectories and movement classification obtained via vt - lane for the purpose of speed estimation and driver behavior calibration for traffic at urban intersections. first, we use a highly instrumented vehicle to verify the estimated speeds obtained from video inference. the results of the speed validation show that our method can estimate the average travel speed of detected vehicles in real - time with an error of 0. 19 m / sec, which is equivalent to 2 % of the average observed travel speeds in the intersection of the study. instantaneous speeds ( at the resolution of 30 hz ) were found to be estimated with an average error of 0. 21 m / sec and 0. 86 m / sec respectively for free - flowing and congested traffic conditions. we then use the estimated speeds to calibrate the parameters of a driver behavior model for the vehicles in the area of study. the results show that the calibrated model replicates the driving behavior with an average error of 0. 45 m / sec, indicating the high potential for using this framework for automated, large - scale calibration of car - following models from roadside traffic video data, which can lead to substantial improvements in traffic modeling via microscopic simulation.
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arxiv:2106.09932
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we establish upper bounds for moments of smoothed quadratic dirichlet character sums under the generalized riemann hypothesis, confirming a conjecture of m. jutila.
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arxiv:2403.14634
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we establish, in the setting of equivariant motivic homotopy theory for a finite group, a version of tom dieck ' s splitting theorem for the fixed points of a suspension spectrum. along the way we establish structural results and constructions for equivariant motivic homotopy theory of independent interest. this includes geometric fixed point functors and the motivic adams isomorphism.
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arxiv:1910.11485
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we report on strong enhancement of mid - infrared second harmonic generation ( shg ) from sic nanopillars due to the resonant excitation of localized surface phonon - polaritons within the reststrahlen band. the magnitude of the shg peak at the monopole mode experiences a strong dependence on the resonant frequency beyond that described by the field localization degree and the dispersion of linear and nonlinear - optical sic properties. comparing the results for the identical nanostructures made of 4h and 6h sic polytypes, we demonstrate the interplay of localized surface phonon polaritons with zone - folded weak phonon modes of the anisotropic crystal. tuning the monopole mode in and out of the region where the zone - folded phonon is excited in 6h - sic, we observe a prominent increase of the already monopole - enhanced shg output when the two modes are coupled. envisioning this interplay as one of the showcase features of mid - infrared nonlinear nanophononics, we discuss its prospects for the effective engineering of nonlinear - optical materials with desired properties in the infrared spectral range.
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arxiv:1607.05158
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our present knowledge of the properties of the various planetary bow shocks is briefly reviewed. we do not follow the astronomical ordering of the planets. we rather distinguish between magnetised and unmagnetised planets which groups mercury and earth with the outer giant planets of the solar system, mars and moon in a separate group lacking magnetic fields and dense atmospheres, and venus together with the comets as the atmospheric celestial objects exposed to the solar wind. asteroids would, in this classification, fall into the group together with the moon and should behave similarly though being much smaller. extrasolar planets are not considered as we have only remote information about their behaviour. the presentation is brief in the sense that our in situ knowledge is rather sporadic yet, depending on just a countable number of bow shock crossings from which just some basic conclusions can be drawn about size, stationarity, shape and nature of the respective shock. the only bow shock of which we have sufficient information to deal in sufficient depth with its physics is earth ' s bow shock. this has been reviewed in other places in this volume and therefore is mentioned here only as the bow shock paradigm in passing.
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arxiv:0808.1701
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developing whole - body tactile skins for robots remains a challenging task, as existing solutions often prioritize modular, one - size - fits - all designs, which, while versatile, fail to account for the robot ' s specific shape and the unique demands of its operational context. in this work, we introduce gentact toolbox, a computational pipeline for creating versatile whole - body tactile skins tailored to both robot shape and application domain. our method includes procedural mesh generation for conforming to a robot ' s topology, task - driven simulation to refine sensor distribution, and multi - material 3d printing for shape - agnostic fabrication. we validate our approach by creating and deploying six capacitive sensing skins on a franka research 3 robot arm in a human - robot interaction scenario. this work represents a shift from " one - size - fits - all " tactile sensors toward context - driven, highly adaptable designs that can be customized for a wide range of robotic systems and applications. the project website is available at https : / / hiro - group. ronc. one / gentacttoolbox
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arxiv:2412.00711
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we present a new method to address multipolar resonances and to control the scattered field of a spherical scatterer. this method is based on the engineering of the multipolar content of the incident beam. we propose experimentally feasible techniques to generate light beams which contain only a few multipolar modes. the techniques uses incident beams with a well defined component of the angular momentum and appropriate focusing with aplanatic lenses. the control of the multipolar content of light beams allow for the excitation of single mie resonances and unprecedented control of the scattered field from spherical particles.
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arxiv:1207.3148
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the unprecedented photorealistic results achieved by recent text - to - image generative systems and their increasing use as plug - and - play content creation solutions make it crucial to understand their potential biases. in this work, we introduce three indicators to evaluate the realism, diversity and prompt - generation consistency of text - to - image generative systems when prompted to generate objects from across the world. our indicators complement qualitative analysis of the broader impact of such systems by enabling automatic and efficient benchmarking of geographic disparities, an important step towards building responsible visual content creation systems. we use our proposed indicators to analyze potential geographic biases in state - of - the - art visual content creation systems and find that : ( 1 ) models have less realism and diversity of generations when prompting for africa and west asia than europe, ( 2 ) prompting with geographic information comes at a cost to prompt - consistency and diversity of generated images, and ( 3 ) models exhibit more region - level disparities for some objects than others. perhaps most interestingly, our indicators suggest that progress in image generation quality has come at the cost of real - world geographic representation. our comprehensive evaluation constitutes a crucial step towards ensuring a positive experience of visual content creation for everyone.
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arxiv:2308.06198
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in recent years, there have been a large number of studies which support violation of statistical isotropy. meanwhile, there are some studies which also found inconsistency. we use the power tensor method defined earlier in the literature to study the new cmbr data. the orientation of these three orthogonal vectors, as well as the power associated with each vector, contains information about possible violation of statistical isotropy. this information is encoded in two entropy measures, the power - entropy and alignment - entropy. we apply this method to wmap 9 - year and planck data. here, we also revisit the statistics to test high - l anomaly reported in our earlier paper and find that the high degree of isotropy seen in earlier wmap 5 - year data is absent in the revised wmap 9 - year data.
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arxiv:1710.09641
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while the accurate description of redox reactions remains a challenge for first - principles calculations, it has been shown that extended hubbard functionals ( dft + u + v ) can provide a reliable approach, mitigating self - interaction errors, in materials with strongly localized d or f electrons. here, we first show that dft + u + v molecular dynamics is capable to follow the adiabatic evolution of oxidation states over time, using representative li - ion cathode materials. in turn, this allows to develop redox - aware machine - learned potentials. we show that considering atoms with different oxidation states ( as accurately predicted by dft + u + v ) as distinct species in the training leads to potentials that are able to identify the correct ground state and pattern of oxidation states for redox elements present. this can be achieved, e. g., through a systematic combinatorial search for the lowest energy configuration or with stochastic methods. this brings the advantages of machine - learned potentials to key technological applications ( e. g., rechargeable batteries ), which require an accurate description of the evolution of redox states.
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arxiv:2412.01652
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data61 and western water worked collaboratively to apply engineering expertise and machine learning tools to find a cost - effective solution to the pipe failure problem in the region west of melbourne, where on average 400 water main failures occur per year. to achieve this objective, we constructed a detailed picture and understanding of the behaviour of the water pipe network by 1 ) discovering the underlying drivers of water main breaks, and 2 ) developing a machine learning system to assess and predict the failure likelihood of water main breaking using historical failure records, descriptors of pipes, and other environmental factors. the ensuing results open up an avenue for western water to identify the priority of pipe renewals
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arxiv:2006.03385
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we present a new analytic fitting profile to model the ram pressure exerted over satellite galaxies on different environments and epochs. the profile is built using the information of the gas particle distribution in hydrodynamical simulations of groups and clusters of galaxies to measure the ram pressure directly. we show that predictions obtained by a previously introduced $ \ beta $ - profile model can not consistently reproduce the dependence of the ram pressure on halocentric distance and redshift for a given halo mass. it features a systematic underestimation of the predicted ram pressure at high redshifts ( $ z > 1. 5 $ ), which increases towards the central regions of the haloes and it is independent of halo mass, reaching differences larger than two decades for satellites at $ r < 0. 4r _ \ mathrm { vir } $. this behaviour reverses as redshift decreases, featuring an increasing over - estimation with halocentric distance at $ z = 0 $. as an alternative, we introduce a new universal analytic model for the profiles which can recover the ram pressure dependence on halo mass, halocentric distance and redshift. we analyse the impact of our new profile on galaxy properties by applying a semi - analytic model of galaxy formation and evolution on top of the simulations. we show that galaxies experiencing large amounts of cumulative ram pressure stripping typically have low stellar masses ( $ m _ \ star \ leq 10 ^ { 9. 5 } \ text { m } _ \ odot $ ). besides, their specific star formation histories depend on the ram pressure modelling applied, particularly at high redshifts ( $ z > 1. 5 $ ).
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arxiv:2102.00132
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multi - modal image fusion ( mmif ) maps useful information from various modalities into the same representation space, thereby producing an informative fused image. however, the existing fusion algorithms tend to symmetrically fuse the multi - modal images, causing the loss of shallow information or bias towards a single modality in certain regions of the fusion results. in this study, we analyzed the spatial distribution differences of information in different modalities and proved that encoding features within the same network is not conducive to achieving simultaneous deep feature space alignment for multi - modal images. to overcome this issue, a multi - modal asymmetric unet ( mma - unet ) was proposed. we separately trained specialized feature encoders for different modal and implemented a cross - scale fusion strategy to maintain the features from different modalities within the same representation space, ensuring a balanced information fusion process. furthermore, extensive fusion and downstream task experiments were conducted to demonstrate the efficiency of mma - unet in fusing infrared and visible image information, producing visually natural and semantically rich fusion results. its performance surpasses that of the state - of - the - art comparison fusion methods.
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arxiv:2404.17747
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