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recently, many organizations have been installing middleboxes in their networks in large numbers to provide various services to their customers. although middleboxes have the advantage of not being dependent on specific hardware and being able to provide a variety of services, they can become a new attack target for hackers. therefore, many researchers have proposed security - enchanced tls protocols, but their results have some limitations. in this paper, we proposed a middlebox - delegated tls ( mdtls ) protocol that not only achieves the same security level but also requires relatively less computation compared to recent research results. mdtls is a tls protocol designed based on the proxy signature scheme, which requires about 39 % less computation than middlebox - aware tls ( matls ), which is the best in security and performance among existing research results. in order to substantiate the enhanced security of mdtls, we conducted a formal verification using the tamarin. our verification demonstrates that mdtls not only satisfies the security properties set forth by matls but also complies with the essential security properties required for proxy signature scheme.
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arxiv:2306.03573
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aims : we have studied the bulge and the disk kinematics of the giant low surface brightness galaxy eso 323 - g064 in order to investigate its dynamical properties and the radial mass profile of the dark matter ( dm ) halo. methods : we observed the galaxy with integral field spectroscopy ( vlt / vimos, in ifu configuration ), measured the positions of the ionized gas by fitting gaussian functions to the o [ iii ] and hbeta emission lines, and fit stellar templates to the galaxy spectra to determine velocity and velocity dispersions. we modeled the stellar kinematics in the bulge with spherical isotropic jeans models and explored the implications of self consistent and dark matter scenarios for nfw and pseudo isothermal halos. results : in the bulge - dominated region, r < 5 ", the emission lines show multi - peaked profiles. the disk dominated region of the galaxy, 13 " < r < 30 ", exhibits regular rotation, with a flat rotation curve that reaches 248 + / - 6 km / sec. from this we estimate the total barionic mass to be m _ bar ~ 1. 9 10 ^ 11 m _ sun and the total dm halo mass to be m _ dm ~ 4. 8 10 ^ 12 m _ sun. the stellar velocity and velocity dispersion have been measured only in the innermost ~ 5 " of the bulge, and reveal a regular rotation with an observed amplitude of 140 km / sec and a central dispersion of sigma = 180 km / sec. our simple jeans modeling shows that dark matter is needed in the central 5 " to explain the kinematics of the bulge, for which we estimate a mass of ( 7 + / - 3 ) 10 ^ 10 m _ sun. however, we are not able to disentangle different dm scenarios. the computed central mass density of the bulge of eso 323 - g064 resembles the central mass density of some high surface brightness galaxies, rather than that of low surface brightness galaxies.
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arxiv:0809.1785
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we present the discovery of deep but sporadic transits in the flux of sbss 1232 + 563, a metal - rich white dwarf polluted by disrupted exoplanetary debris. nearly 25 years of photometry from multiple sky surveys reveal evidence of occasional dimming of the white dwarf, most notably evident in an 8 - months - long event in 2023 that caused a > 40 % drop in flux from the star. in - transit follow - up shows additional short - timescale ( minutes - to hours - long ) dimming events. tess photometry suggests a coherent 14. 842 - hr signal that could represent the dominant orbital period of debris. six low - resolution spectra collected at various transit depths over two decades show no evidence of significant changes in the observed elemental abundances. sbss 1232 + 563 demonstrates that debris transits around white dwarfs can be sporadic, with many years of inactivity before large - amplitude dimming events.
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arxiv:2501.02050
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we develop further basic tools in the theory of continuous bounded cohomology of locally compact groups. we apply this tools to establish a milnor - wood type inequality in a very general context and to prove a global rigidity result which was originally announced by the authors with a sketch of a proof using bounded cohomology techniques and then proven by koziarz and maubon using harmonic map techniques. as a corollary one obtains that a lattice in su ( p, 1 ) cannot be deformed nontrivially in su ( q, 1 ), if either p is at least 2 or the lattice is cocompact. this generalizes to noncocompact lattices a theorem of goldman and millson.
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arxiv:math/0505069
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relation extraction ( re ) is the task of extracting semantic relationships between entities in a sentence and aligning them to relations defined in a vocabulary, which is generally in the form of a knowledge graph ( kg ) or an ontology. various approaches have been proposed so far to address this task. however, applying these techniques to biomedical text often yields unsatisfactory results because it is hard to infer relations directly from sentences due to the nature of the biomedical relations. to address these issues, we present a novel technique called reonto, that makes use of neuro symbolic knowledge for the re task. reonto employs a graph neural network to acquire the sentence representation and leverages publicly accessible ontologies as prior knowledge to identify the sentential relation between two entities. the approach involves extracting the relation path between the two entities from the ontology. we evaluate the effect of using symbolic knowledge from ontologies with graph neural networks. experimental results on two public biomedical datasets, biorel and ade, show that our method outperforms all the baselines ( approximately by 3 \ % ).
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arxiv:2309.01370
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we prove that a holomorphic fixed point germ in two complex variables, tangent to the identity, and whose only characteristic direction is non - degenerate, has a domain of attraction on which the map is conjugate to a translation. in the case of a global automorphism, the corresponding domain of attraction is a fatou - bieberbach domain.
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arxiv:1202.0269
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metal - air batteries are among the most promising next - generation energy storage devices. relying on abundant materials and offering high energy densities, potential applications lie in the fields of electro - mobility, portable electronics, and stationary grid applications. now, research on secondary zinc - air batteries is revived, which are commercialized as primary hearing aid batteries. one of the main obstacles for making zinc - air batteries rechargeable is their poor lifetime due to the degradation of alkaline electrolyte in contact with atmospheric carbon dioxide. in this article, we present a continuum theory of a commercial varta powerone button cell. our model contains dissolution of zinc and nucleation and growth of zinc oxide in the anode, thermodynamically consistent electrolyte transport in porous media, and multi - phase coexistance in the gas diffusion electrode. we perform electrochemical measurements and validate our model. excellent agreement between theory and experiment is found and novel insights into the role of zinc oxide nucleation and growth and carbon dioxide dissolution for discharge and lifetime is presented. we demonstrate the implications of our work for the development of rechargeable zinc - air batteries.
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arxiv:1612.03464
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in this paper, we study the initial - boundary value problem of one - dimensional isentropic compressible euler equations with the source term $ \ beta \ rho | u | ^ { \ alpha } u $. by means of wave decomposition and the uniform a - priori estimates, we prove the global existence of smooth solutions under small perturbations around the supersonic fanno flow. then, by gronwall ' s inequality, we get the smooth solution is time - periodic.
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arxiv:2204.01939
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we show that if $ k $ is a self - similar $ 1 $ - set that is not contained in a line and either satisfies the strong separation condition or is defined via homotheties then there are at most finitely many lines through the origin such that the projection of $ k $ onto them is an interval.
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arxiv:1611.05948
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visual grounding is a task that aims to locate a target object according to a natural language expression. as a multi - modal task, feature interaction between textual and visual inputs is vital. however, previous solutions mainly handle each modality independently before fusing them together, which does not take full advantage of relevant textual information while extracting visual features. to better leverage the textual - visual relationship in visual grounding, we propose a query - conditioned convolution module ( qcm ) that extracts query - aware visual features by incorporating query information into the generation of convolutional kernels. with our proposed qcm, the downstream fusion module receives visual features that are more discriminative and focused on the desired object described in the expression, leading to more accurate predictions. extensive experiments on three popular visual grounding datasets demonstrate that our method achieves state - of - the - art performance. in addition, the query - aware visual features are informative enough to achieve comparable performance to the latest methods when directly used for prediction without further multi - modal fusion.
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arxiv:2206.09114
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artin solved hilbert ' s 17th problem, proving that a real polynomial in $ n $ variables that is positive semidefinite is a sum of squares of rational functions, and pfister showed that only $ 2 ^ n $ squares are needed. in this paper, we investigate situations where pfister ' s theorem may be improved. we show that a real polynomial of degree $ d $ in $ n $ variables that is positive semidefinite is a sum of $ 2 ^ n - 1 $ squares of rational functions if $ d \ leq 2n - 2 $. if $ n $ is even, or equal to $ 3 $ or $ 5 $, this result also holds for $ d = 2n $.
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arxiv:1602.07330
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recent breakthroughs in defenses against adversarial examples, like adversarial training, make the neural networks robust against various classes of attackers ( e. g., first - order gradient - based attacks ). however, it is an open question whether the adversarially trained networks are truly robust under unknown attacks. in this paper, we present interval attacks, a new technique to find adversarial examples to evaluate the robustness of neural networks. interval attacks leverage symbolic interval propagation, a bound propagation technique that can exploit a broader view around the current input to locate promising areas containing adversarial instances, which in turn can be searched with existing gradient - guided attacks. we can obtain such a broader view using sound bound propagation methods to track and over - approximate the errors of the network within given input ranges. our results show that, on state - of - the - art adversarially trained networks, interval attack can find on average 47 % relatively more violations than the state - of - the - art gradient - guided pgd attack.
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arxiv:1906.02282
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in this survey, we dive into tabular data learning ( tdl ) using graph neural networks ( gnns ), a domain where deep learning - based approaches have increasingly shown superior performance in both classification and regression tasks compared to traditional methods. the survey highlights a critical gap in deep neural tdl methods : the underrepresentation of latent correlations among data instances and feature values. gnns, with their innate capability to model intricate relationships and interactions between diverse elements of tabular data, have garnered significant interest and application across various tdl domains. our survey provides a systematic review of the methods involved in designing and implementing gnns for tdl ( gnn4tdl ). it encompasses a detailed investigation into the foundational aspects and an overview of gnn - based tdl methods, offering insights into their evolving landscape. we present a comprehensive taxonomy focused on constructing graph structures and representation learning within gnn - based tdl methods. in addition, the survey examines various training plans, emphasizing the integration of auxiliary tasks to enhance the effectiveness of instance representations. a critical part of our discussion is dedicated to the practical application of gnns across a spectrum of gnn4tdl scenarios, demonstrating their versatility and impact. lastly, we discuss the limitations and propose future research directions, aiming to spur advancements in gnn4tdl. this survey serves as a resource for researchers and practitioners, offering a thorough understanding of gnns ' role in revolutionizing tdl and pointing towards future innovations in this promising area.
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arxiv:2401.02143
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gravitinos and axinos produced in the late decays of other supersymmetric particles are well - motivated dark matter ( dm ) candidates, whose experimental evidences are very distinctive and different from other standard candidates, as thermal produced neutralinos in similar supersymmetric models. in particular, charged sleptons could appear stable because of the length of its lifetime. the direct production of such particles at both the large hadron collider ( lhc ) and a future international linear collider ( ilc ) can give not only a clear signature of supersymmetry but also the first non - gravitational evidence of dark matter.
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arxiv:hep-ph/0701011
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as alignment links are not given between english sentences and abstract meaning representation ( amr ) graphs in the amr annotation, automatic alignment becomes indispensable for training an amr parser. previous studies formalize it as a string - to - string problem and solve it in an unsupervised way, which suffers from data sparseness due to the small size of training data for english - amr alignment. in this paper, we formalize it as a syntax - based alignment problem and solve it in a supervised manner based on syntax trees, which can address the data sparseness problem by generalizing english - amr tokens to syntax tags. experiments verify the effectiveness of the proposed method not only for english - amr alignment, but also for amr parsing.
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arxiv:1606.02126
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the survival of salmonella spp. as pathogen indicator in composting was studied. the inoculums technique was used to gives the known amounts of salmonella spp. involved in composting. the inoculums of salmonella spp. solution was added directly into the compost material. the direct inoculum was compared with inoculums in vial technique. the salmonella spp. solution placed into a vial and inserted into the middle of compost material before starting the composting process. the conventional method that is used for the enumeration of salmonella spp. is serial dilution followed by standard membrane filtration as recommended in the compost quality standard method pas 100 and the british standard ( bs en iso 6579 : 2002 ). this study was designed to investigate the relationship of temperature and contact material that may also involve in pathogen activation specifically to salmonella spp. the exposure to an average temperature during composting of about 55 - 60 { \ deg } c was kept for at least 3 days as it was reported sufficiently kills the vast majority of enteric pathogen ( deportes et al., 1995 ). the amount of salmonella spp. and temperature for both samples was set as indicator to determine the survival of salmonella spp. in direct and non - direct inoculums. this study gives the figures of die - off rate for salmonella spp. during composting. the differentiation between direct contact ( sample a ) and non - contact of salmonella spp. with compost material ( sample b ) during composting was also revealed. the results from laboratory scale of composting study has been showed that after 8 days ( which included at least at 66 { \ deg } c ) the numbers of salmonella spp. in sample a were below the limits in uk compost standard ( known as pas 100 ) ( bsi, 2005 ) which required the compost to be free of salmonella spp. meanwhile, sample b still gives high amount of salmonella spp. in even after composting for 20 days.
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arxiv:1404.5212
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a rigorous proof for convergence of the wolf method for calculating electrostatic energy of a periodic lattice is presented. in particular, we show that for an arbitrary lattice of unit cells, the lattice sum obtained via wolf method converges to the one obtained via ewald method.
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arxiv:1102.0049
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wireless sensor networks ( wsns ) enable a wealth of new applications where remote estimation is essential. individual sensors simultaneously sense a dynamic process and transmit measured information over a shared channel to a central fusion center. the fusion center computes an estimate of the process state by means of a kalman filter. in this paper we assume that the wsn admits a tree topology with fusion center at the root. at each time step only a subset of sensors can be selected to transmit observations to the fusion center due to a limited energy budget. we propose a stochastic sensor selection algorithm that randomly selects a subset of sensors according to certain probability distribution, which is opportunely designed to minimize the asymptotic expected estimation error covariance matrix. we show that the optimal stochastic sensor selection problem can be relaxed into a convex optimization problem and thus solved efficiently. we also provide a possible implementation of our algorithm which does not introduce any communication overhead. the paper ends with some numerical examples that show the effectiveness of the proposed approach.
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arxiv:1107.1752
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new experimental data on 2 + energies of 136, 138sn confirms the trend of lower 2 + excitation energies of even - even tin isotopes with n > 82 compared to those with n < 82. however, none of the theoretical predictions using both realistic and empirical interactions can reproduce experimental data on excitation energies as well as the transition probabilities ( b ( e2 ; 6 + - > 4 + ) ) of these nuclei, simultaneously, apart from one whose matrix elements have been changed empirically to produce mixed seniority states by weakening pairing. we have shown that the experimental result also shows good agreement with the theory in which three body forces have been included in a realistic interaction. the new theoretical results on transition probabilities have been discussed to identify the experimental quantities which will clearly distinguish between different views.
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arxiv:1411.2353
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we investigate the translational and rotational relaxation dynamics of a crowded two - dimensional system of monodisperse penrose kites, in which crystallization, quasi - crystallization, and nematic ordering are suppressed, from low to high area fractions along the metastable ergodic fluid branch. first, we demonstrate a decoupling between both the translational and the rotational diffusion coefficients and the relaxation time : the diffusivities are not inversely proportional to the relaxation time, neither in the low - density normal liquid regime nor in the high - density supercooled regime. our simulations reveal that this inverse proportionality breaks in the normal liquid regime due to the mermin - wagner long - wavelength fluctuations and in the supercooled regime due to the dynamical heterogeneities. we then show that dynamical heterogeneities are mainly spatial for translational degrees of freedom and temporal for rotational ones, that there is no correlation between the particles with the largest translational and rotational displacements, and that different dynamical length scales characterize the translational and the rotational motion. hence, despite the translational and the rotational glass - transition densities coincide, according to a mode - coupling fit, translations and rotations appear to decorrelate via different dynamical processes.
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arxiv:1912.04449
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we studied the abundance of hcn, h13cn, and hn13c in a sample of prestellar cores, in order to search for species associated with high density gas. we used the iram 30m radiotelescope to observe along the major and the minor axes of l1498, l1521e, and tmc 2, three cores chosen on the basis of their co depletion properties. we mapped the j = 1 - 0 transition of hcn, h13cn, and hn13c towards the source sample plus the j = 1 - 0 transition of n2h + and the j = 2 - 1 transition of c18o in tmc 2. we used two different radiative transfer codes, making use of recent collisional rate calculations, in order to determine more accurately the excitation temperature, leading to a more exact evaluation of the column densities and abundances. we find that the optical depths of both h13cn ( 1 - 0 ) and hn13c ( 1 - 0 ) are non - negligible, allowing us to estimate excitation temperatures for these transitions in many positions in the three sources. the observed excitation temperatures are consistent with recent computations of the collisional rates for these species and they correlate with hydrogen column density inferred from dust emission. we conclude that hcn and hnc are relatively abundant in the high density zone, n ( h2 ) about 10 ^ 5 cm - 3, where co is depleted. the relative abundance [ hnc ] / [ hcn ] differs from unity by at most 30 per cent consistent with chemical expectations. the three hyperfine satellites of hcn ( 1 - 0 ) are optically thick in the regions mapped, but the profiles become increasingly skewed to the blue ( l1498 and tmc 2 ) or red ( l1521e ) with increasing optical depth suggesting absorption by foreground layers.
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arxiv:1108.5073
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we study structural properties of trees grown by preferential attachment. in this mechanism, nodes are added sequentially and attached to existing nodes at a rate that is strictly proportional to the degree. we classify nodes by their depth n, defined as the distance from the root of the tree, and find that the network is strongly stratified. most notably, the distribution f _ k ^ ( n ) of nodes with degree k at depth n has a power - law tail, f _ k ^ ( n ) ~ k ^ { - \ gamma ( n ) }. the exponent grows linearly with depth, gamma ( n ) = 2 + ( n - 1 ) / < n - 1 >, where the brackets denote an average over all nodes. therefore, nodes that are closer to the root are better connected, and moreover, the degree distribution strongly varies with depth. similarly, the in - component size distribution has a power - law tail and the characteristic exponent grows linearly with depth. qualitatively, these behaviors extend to a class of networks that grow by a redirection mechanism.
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arxiv:0905.1920
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an elementary presentation of the methods for the canonical quantization of constraint systems with fermi variables is given. the emphasis is on the subtleties of the construction of an appropriate classical bracket that could be consistently replaced by commutators or anti - - commutators of operators, as required by canonical quantization procedure for bosonic and fermionic degrees of freedom respectively. i present a consequent canonical quantization of the dirac field, in which the role of poincar \ ' e invariance is made marginal. this simple example provides an introduction to the poincar \ ' e - - free quantization of spinor electrodynamics in the second part of the paper.
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arxiv:1010.5797
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recently deep neural networks ( dnns ) have been used to learn speaker features. however, the quality of the learned features is not sufficiently good, so a complex back - end model, either neural or probabilistic, has to be used to address the residual uncertainty when applied to speaker verification, just as with raw features. this paper presents a convolutional time - delay deep neural network structure ( ct - dnn ) for speaker feature learning. our experimental results on the fisher database demonstrated that this ct - dnn can produce high - quality speaker features : even with a single feature ( 0. 3 seconds including the context ), the eer can be as low as 7. 68 %. this effectively confirmed that the speaker trait is largely a deterministic short - time property rather than a long - time distributional pattern, and therefore can be extracted from just dozens of frames.
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arxiv:1705.03670
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we study orbital and physical properties of trojan asteroids of jupiter. we try to discern all families previously discussed in literature, but we conclude there is only one significant family among trojans, namely the cluster around asteroid ( 3548 ) eurybates. it is the only cluster, which has all of the following characteristics : ( i ) it is clearly concentrated in the proper - element space ; ( ii ) size - frequency distribution is different from background asteroids ; ( iii ) we have a reasonable collisional / dynamical model of the family. henceforth, we can consider it as a real collisional family. we also report a discovery of a possible family around the asteroid ( 4709 ) ennomos, composed mostly of small asteroids. the asteroid ( 4709 ) ennomos is known to have a very high albedo $ p _ v \ simeq 0. 15 $, which may be related to a hypothetical cratering event which exposed ice ( fern \ ' andez et al. 2003 ). the relation between the collisional family and the exposed surface of the parent body is a unique opportunity to study the physics of cratering events. however, more data are needed to confirm the existence of this family and its relationship with ennomos.
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arxiv:1109.1109
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recently dolgov and pozdnyakov proposed a new baryogenesis mechanism in which baryon asymmetry is produced without violating baryon number at the lagrangian level. in this scenario, baryon asymmetry is generated by absorption of a new particle x carrying baryon number onto primordial black holes ( pbhs ). assuming cp - violation, the particle x is absorbed at a different rate than the antiparticle $ \ bar { x } $, producing an asymmetry in the baryonic number. we independently test this scenario, finding that it suffers from two fundamental issues. \ \ at the phenomenological level, strong absorption by pbhs initially increases the baryon asymmetry. however, at later times such asymmetry is completely absorbed by pbhs. in order to overcome this issue, we account for pbh evaporation, which provides a natural way of halting the absorption while keeping a finite baryon asymmetry. we provide a systematic study of the parameter space, identifying the regions leading to the production of the baryon asymmetry without violating the known constraints on pbhs concentration. at the theoretical level, a model realizing the cp - violation postulated in this scenario is difficult to realize. we show, by implementing a minimal model, that the framework proposed in the original work in order to produce cp - violation, even if qualitatively correct, is quantitatively in disagreement with the observed baryon asymmetry, namely this mechanism produces only a fraction of the total baryon asymmetry.
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arxiv:2106.11980
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the increasing popularity of regression discontinuity methods for causal inference in observational studies has led to a proliferation of different estimating strategies, most of which involve first fitting non - parametric regression models on both sides of a treatment assignment boundary and then reporting plug - in estimates for the effect of interest. in applications, however, it is often difficult to tune the non - parametric regressions in a way that is well calibrated for the specific target of inference ; for example, the model with the best global in - sample fit may provide poor estimates of the discontinuity parameter. in this paper, we propose an alternative method for estimation and statistical inference in regression discontinuity designs that uses numerical convex optimization to directly obtain the finite - sample - minimax linear estimator for the regression discontinuity parameter, subject to bounds on the second derivative of the conditional response function. given a bound on the second derivative, our proposed method is fully data - driven, and provides uniform confidence intervals for the regression discontinuity parameter with both discrete and continuous running variables. the method also naturally extends to the case of multiple running variables.
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arxiv:1705.01677
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reduced exciton mass, polarizability, and dielectric constant of the surrounding medium are essential properties for semiconducting materials, and they have been extracted recently from the magnetoexciton energies. however, the acceptable accuracy of the suggested method requires very high magnetic intensity. therefore, in the present paper, we propose an alternative method of extracting these material properties from recently available experimental magnetoexciton s - state energies in monolayer transition - metal dichalcogenides ( tmdcs ). the method is based on the high sensitivity of exciton energies to the material parameters in the rytova - keldysh model. it allows us to vary the considered material parameters to get the best fit of the theoretical calculation to the experimental exciton energies for the $ 1s $, $ 2s $, and $ 3s $ states. this procedure gives values of the exciton reduced mass and $ 2d $ polarizability. then, the experimental magnetoexciton spectra compared to the theoretical calculation also determine the average dielectric constant. concrete applications are presented only for monolayers wse $ _ 2 $ and ws $ _ 2 $ from the recently available experimental data ; however, the presented approach is universal and can be applied to other monolayer tmdcs. the mentioned fitting procedure requires a fast and effective method of solving the schr \ " { o } dinger equation of an exciton in monolayer tmdcs with a magnetic field. therefore, we also develop such a method in this paper for highly accurate magnetoexciton energies.
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arxiv:2303.08089
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we prove a conjecture by d. zeilberger on the determinant of a certain matrix and relate it to a problem of non - existence of 1 - cycles in this note.
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arxiv:1402.0020
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we report doppler measurements of the stars hd187085 and hd20782 which indicate two high eccentricity low - mass companions to the stars. we find hd187085 has a jupiter - mass companion with a ~ 1000d orbit. our formal ` best fit ' solution suggests an eccentricity of 0. 47, however, it does not sample the periastron passage of the companion and we find that orbital solutions with eccentricities between 0. 1 and 0. 8 give only slightly poorer fits ( based on rms and chi ^ 2 ) and are thus plausible. observations made during periastron passage in 2007 june should allow for the reliable determination of the orbital eccentricity for the companion to hd187085. our dataset for hd20782 does sample periastron and so the orbit for its companion can be more reliably determined. we find the companion to hd20782 has m sin i = 1. 77 + / - 0. 22m _ jup, an orbital period of 595. 86 + / - 0. 03d and an orbit with an eccentricity of 0. 92 + / - 0. 03. the detection of such high - eccentricity ( and relatively low velocity amplitude ) exoplanets appears to be facilitated by the long - term precision of the anglo - australian planet search. looking at exoplanet detections as a whole, we find that those with higher eccentricity seem to have relatively higher velocity amplitudes indicating higher mass planets and / or an observational bias against the detection of high eccentricity systems.
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arxiv:astro-ph/0603335
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analysing next - generation cosmological data requires balancing accurate modeling of non - linear gravitational structure formation and computational demands. we propose a solution by introducing a machine learning - based field - level emulator, within the hamiltonian monte carlo - based bayesian origin reconstruction from galaxies ( borg ) inference algorithm. built on a v - net neural network architecture, the emulator enhances the predictions by first - order lagrangian perturbation theory to be accurately aligned with full $ n $ - body simulations while significantly reducing evaluation time. we test its incorporation in borg for sampling cosmic initial conditions using mock data based on non - linear large - scale structures from $ n $ - body simulations and gaussian noise. the method efficiently and accurately explores the high - dimensional parameter space of initial conditions, fully extracting the cross - correlation information of the data field binned at a resolution of $ 1. 95h ^ { - 1 } $ mpc. percent - level agreement with the ground truth in the power spectrum and bispectrum is achieved up to the nyquist frequency $ k _ \ mathrm { n } \ approx 2. 79h \ ; \ mathrm { mpc } ^ { - 1 } $. posterior resimulations - using the inferred initial conditions for $ n $ - body simulations - show that the recovery of information in the initial conditions is sufficient to accurately reproduce halo properties. in particular, we show highly accurate $ m _ { 200 \ mathrm { c } } $ halo mass function and stacked density profiles of haloes in different mass bins $ [ 0. 853, 16 ] \ times 10 ^ { 14 } m _ { \ odot } h ^ { - 1 } $. as all available cross - correlation information is extracted, we acknowledge that limitations in recovering the initial conditions stem from the noise level and data grid resolution. this is promising as it underscores the significance of accurate non - linear modeling, indicating the potential for extracting additional information at smaller scales.
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arxiv:2312.09271
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these notes contain an introduction to the theory of complex semisimple quantum groups. our main aim is to discuss the classification of irreducible harish - chandra modules for these quantum groups, following joseph and letzter. along the way we cover extensive background material on quantized universal enveloping algebras and explain connections to the analytical theory in the setting of locally compact quantum groups.
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arxiv:1705.05661
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lens spaces are the only 3 - manifolds that admit gradient - like flows with four fixed points. this is an immediate corollary of morse inequality and of the morse function with four critical points existence. a similar question for gradient - like diffeomorphisms is open. solution can be approached by describing a complete topological conjugacy invariant of the class of considered diffeomorphisms and constructing of representative diffeomorphism for every conjugacy class by the abstract invariant. ch. bonnati and v. z. grines proved that the topological conjugacy class of morse - smale flows with unique saddle is defined by the equivalence class of the hopf knot in $ \ mathbb s ^ 2 \ times \ mathbb s ^ 1 $ which is projection of one - dimensional saddle separatrice and used the mentioned approach to prove that the ambient manifold of a diffeomorphism of this class is the three - dimensional sphere. in the present paper similar result is obtained for the gradient - like diffeomorphisms with exactly two saddle points and the unique heteroclinic curve.
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arxiv:2209.04815
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we provide local formulas for the pressure of incompressible fluids. the pressure can be expressed in terms of its average and averages of squares of velocity increments in arbitrary small neighborhoods. as application, we give a brief proof of the fact that $ c ^ { \ alpha } $ velocities have $ c ^ { 2 \ alpha } $ ( or lipschitz ) pressures. we also give some regularity criteria for 3d incompressible navier - stokes equations.
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arxiv:1309.5789
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the fast bunch integrator is a bunch intensity monitor designed around the measurements made from resistive wall current monitors. during the run ii period these were used in both tevatron and main injector for single and multiple bunch intensity measurements. this paper presents an overview of the design and use of these systems during this period.
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arxiv:1209.2714
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investigations of high - energy graviton - graviton and gluon - gluon scattering are performed in the leading eikonal approximation for the kinematic regime of large center of mass energy and low momentum transfer. we find a double copy relation between the amplitudes of the two theories to all loop orders when, on the gauge theory side, we retain only the set of diagrams at each loop order for which the collinear divergences cancel amongst themselves. for this to happen the color structure of all diagrams in the set must be identical. using standard field theoretic methods, it is shown that this relation is reflected in a similar double copy relationship between the classical shockwaves of the two theories as well.
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arxiv:1210.8111
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egocentric vision systems aim to understand the spatial surroundings and the wearer ' s behavior inside it, including motions, activities, and interaction with objects. since a person ' s attention and situational responses are influenced by their physiological state, egocentric systems must also detect this state for better context awareness. in this paper, we propose egoppg, a novel task for egocentric vision systems to extract a person ' s heart rate ( hr ) as a key indicator of the wearer ' s physiological state from the system ' s built - in sensors ( e. g., eye tracking videos ). we then propose egopulseformer, a method that solely takes eye - tracking video as input to estimate a person ' s photoplethysmogram ( ppg ) from areas around the eyes to track hr values - without requiring additional or dedicated hardware. we demonstrate the downstream benefit of egopulseformer on egoexo4d, where we find that augmenting existing models with tracked hr values improves proficiency estimation by 14 %. to train and validate egopulseformer, we collected a dataset of 13 + hours of eye - tracking videos from project aria and contact - based blood volume pulse signals as well as an electrocardiogram ( ecg ) for ground - truth hr values. 25 participants performed diverse everyday activities such as office work, cooking, dancing, and exercising, which induced significant natural motion and hr variation ( 44 - 164 bpm ). our model robustly estimates hr ( mae = 8. 82 bpm ) and captures patterns ( r = 0. 81 ). our results show how egocentric systems may unify environmental and physiological tracking to better understand user actions and internal states.
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arxiv:2502.20879
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micro - raman spectroscopy has become an important tool in probing thermophysical behavior in emerging functional materials such as two - dimensional ( 2d ) layered structures. localized heating by the focused raman excitation laser beam is expected to produce both stress and nonequilibrium temperature distributions in the material. here we investigate the effects of hot optical phonons in the raman spectra of molybdenum disulphide ( mos2 ) and distinguish them from those caused by thermally - induced compressive stress, which causes a raman frequency blue shift in the focused raman laser spot. with the stress effect accounted for in micro - raman measurements, the degree of nonequilibrium between the hot optical phonons and the acoustic phonon bath is found to be much smaller than those observed in prior micro - raman measurements of suspended graphene. the observation agrees with a first - principles based theoretical prediction of overpopulated zone - center optical phonons compared to other optical phonons in the brillouin zone and acoustic phonons. the findings provide detailed insight into the energy relaxation processes in this emerging 2d transition metal dichalcogenide ( tmd ) electronic and optoelectronic material and clarify an important question in micro - raman measurements of thermal transport in this and other 2d materials.
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arxiv:2206.15473
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this is a colloquium - style introduction to two electronic processes in a carbon monolayer ( graphene ), each having an analogue in relativistic quantum mechanics. both processes couple electron - like and hole - like states, through the action of either a superconducting pair potential or an electrostatic potential. the first process, andreev reflection, is the electron - to - hole conversion at the interface with a superconductor. the second process, klein tunneling, is the tunneling through a p - n junction. existing and proposed experiments on josephson junctions and bipolar junctions in graphene are discussed from a unified perspective. contents : i. introduction ii. basic physics of graphene ( dirac equation ; time reversal symmetry ; boundary conditions ; pseudo - diffusive dynamics ) iii. andreev reflection ( electron - hole conversion ; retro - reflection vs. specular reflection ; dirac - bogoliubov - de gennes equation ; josephson junctions ; further reading ) iv. klein tunneling ( absence of backscattering ; bipolar junctions ; magnetic field effects ; further reading ) v. analogies ( mapping between ns and p - n junction ; retro - reflection vs. negative refraction ; valley - isospin dependent quantum hall effect ; pseudo - superconductivity )
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arxiv:0710.3848
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altermagnets have emerged as a class of materials combining certain ferromagnetic properties with zero net magnetization. this combination is highly promising for spintronics, especially if a material can be brought to a nanoscale size. however, experimental studies of the 2d limit of altermagnets and evolution of their properties with thickness are lacking. here, we study epitaxial films on silicon of the weyl altermagnet gdalsi ranging from more than a hundred unit cells to a single unit cell. the films are synthesized by molecular beam epitaxy and, expectedly, do not show any discernible net magnetic moments. electron transport studies reveal a remarkable transformation of the electron state with the film thickness. thick films exhibit negative longitudinal magnetoresistance associated with the chiral anomaly but do not demonstrate altermagnetic properties in electron transport due to symmetry restrictions. in ultrathin films, a spontaneous anomalous hall effect manifests itself, indicating a non - relativistic spin splitting in the electronic structure. the transformation is associated with crystal symmetry breaking accompanying the 3d - to - 2d crossover. the work highlights the role of dimensionality in altermagnetism and provides a platform for studies of altermagnets aiming at ultra - compact spintronics.
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arxiv:2406.07172
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we study a system of two distant quantum emitters coupled via a one - dimensional waveguide where the electromagnetic field has a direction - dependent velocity. as a consequence, the onset of collective emission is non - simultaneous and, for appropriate parameters, while one of the emitters exhibits superradiance the other can be subradiant. interference effects enable the system to radiate in a preferential direction depending on the atomic state and the field propagation phases. we characterize such directional emission as a function of various parameters, delineating the conditions for optimal directionality.
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arxiv:2108.12951
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the degree polynomial of a multigraph $ g $ is given by $ \ sum _ { v \ in v ( g ) } x ^ { \ mbox { deg } ( v ) } $. we investigate here properties of the roots of such polynomials. in addition to examining the roots for some families of graphs with few and many degrees, we provide some bounds on the moduli of the roots. we also propose a region that contains all roots for multigraphs of order $ n $.
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arxiv:2505.04882
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the gravitational wave ( gw ) signal from the merger of two black holes can serve as a standard sirens for cosmological inference. however, a degeneracy exists between the luminosity distance and the inclination angle between the binary system ' s orbital angular momentum and the observer ' s line of sight, limiting the precise measurement of the luminosity distance. in this study, we investigate how higher harmonics affect luminosity distance estimation for third - generation ( 3g ) gw detectors in binary black hole mergers. our findings demonstrate that considering higher harmonics significantly enhances distance inference results compared with using only the ( 2, 2 ) mode. this improved accuracy in distance estimates also strengthens constraints on host galaxies, enabling more precise measurements of the hubble constant. these results highlight the significant influence of higher harmonics on the range estimation accuracy of 3g ground - based gw detectors.
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arxiv:2405.11279
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temporal networks representing a stream of timestamped edges are seemingly ubiquitous in the real - world. however, the massive size and continuous nature of these networks make them fundamentally challenging to analyze and leverage for descriptive and predictive modeling tasks. in this work, we propose a general framework for temporal network sampling with unbiased estimation. we develop online, single - pass sampling algorithms and unbiased estimators for temporal network sampling. the proposed algorithms enable fast, accurate, and memory - efficient statistical estimation of temporal network patterns and properties. in addition, we propose a temporally decaying sampling algorithm with unbiased estimators for studying networks that evolve in continuous time, where the strength of links is a function of time, and the motif patterns are temporally - weighted. in contrast to the prior notion of a $ \ bigtriangleup t $ - temporal motif, the proposed formulation and algorithms for counting temporally weighted motifs are useful for forecasting tasks in networks such as predicting future links, or a future time - series variable of nodes and links. finally, extensive experiments on a variety of temporal networks from different domains demonstrate the effectiveness of the proposed algorithms. a detailed ablation study is provided to understand the impact of the various components of the proposed framework.
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arxiv:1910.08657
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bright and dark solitons of the cubic nonlinear schrodinger equation are used to construct complex - valued potentials with all - real spectrum. the real part of these potentials is equal to the intensity of a bright soliton while their imaginary part is defined by the product of such soliton with its concomitant, a dark soliton. considering light propagation in kerr media, the real part of the potential refers to the self - focusing of the signal and the imaginary one provides the system with balanced gain - and - loss rates.
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arxiv:1805.00058
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today is a time of rapid e - commerce development, and jing dong, china ' s e - commerce giant, has taken its place in the highly competitive industry with its self - built logistics system. this paper analyzed the impact of jing dong ' s self - built logistics system characteristics on user satisfaction and continuous use intention by using the technology acceptance model as the theoretical framework. this paper collected 295 valid samples using a questionnaire survey ; all the respondents are users and potential users of jing dong from mainland china. the empirical results of data analysis showed that marketing information quality, logistics system quality, and logistics service have significant effects on the perceived usefulness of jing dong ' s self - built logistics, while only marketing information quality and logistics system quality have significant effects on the perceived usefulness of self - built logistics among the self - built logistics system characteristics dimensions. additionally, the willingness to continue using a product and user satisfaction were both directly and significantly impacted by perceived usefulness ; perceived ease of use had an indirect impact on users ' willingness to continue use by affecting perceived usefulness and user satisfaction, and user satisfaction has the most significant impact on users ' continuous use of jing dong shopping and using jing dong self - built logistics.
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arxiv:2407.15011
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integrated models are a popular tool for analyzing species of conservation concern. species of conservation concern are often monitored by multiple entities that generate several datasets. individually, these datasets may be insufficient for guiding management due to low spatio - temporal resolution, biased sampling, or large observational uncertainty. integrated models provide an approach for assimilating multiple datasets in a coherent framework that can compensate for these deficiencies. while conventional integrated models have been used to assimilate count data with surveys of survival, fecundity, and harvest, they can also assimilate ecological surveys that have differing spatio - temporal regions and observational uncertainties. motivated by independent aerial and ground surveys of lesser prairie - chicken, we developed an integrated modeling approach that assimilates density estimates derived from surveys with distinct sources of observational error into a joint framework that provides shared inference on spatio - temporal trends. we model these data using a bayesian markov melding approach and apply several data augmentation strategies for efficient sampling. in a simulation study, we show that our integrated model improved predictive performance relative to models that analyzed the surveys independently. we use the integrated model to facilitate prediction of lesser prairie - chicken density at unsampled regions and perform a sensitivity analysis to quantify the inferential cost associated with reduced survey effort.
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arxiv:2211.12642
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in interactive multi - agent settings, decision - making and planning are challenging mainly due to the agents ' interconnected objectives. dynamic game theory offers a formal framework for analyzing such intricacies. yet, solving constrained dynamic games and determining the interaction outcome in the form of generalized nash equilibria ( gne ) pose computational challenges due to the need for solving constrained coupled optimal control problems. in this paper, we address this challenge by proposing to leverage the special structure of many real - world multi - agent interactions. more specifically, our key idea is to leverage constrained dynamic potential games, which are games for which gne can be found by solving a single constrained optimal control problem associated with minimizing the potential function. we argue that constrained dynamic potential games can effectively facilitate interactive decision - making in many multi - agent interactions. we will identify structures in realistic multi - agent interactive scenarios that can be transformed into weighted constrained potential dynamic games ( wcpdgs ). we will show that the gne of the resulting wcpdg can be obtained by solving a single constrained optimal control problem. we will demonstrate the effectiveness of the proposed method through various simulation studies and show that we achieve significant improvements in solve time compared to state - of - the - art game solvers. we further provide experimental validation of our proposed method in a navigation setup involving two quadrotors carrying a rigid object while avoiding collisions with two humans.
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arxiv:2308.05876
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using integral field spectroscopy from manga, we study the resolved microstructures in a shocked region in criss cross nebula ( ccn ), with an unprecedentedly high resolution of $ \ lesssim $ 1000 au. we measure surface brightness maps for 34 emission lines, which can be broadly divided into three categories : ( 1 ) the [ oiii ] $ \ lambda $ 5007 - like group including seven high - ionization lines and two [ oii ] auroral lines which uniformly present a remarkable lane structure, ( 2 ) the h $ \ alpha $ $ \ lambda $ 6563 - like group including 23 low - ionization or recombination lines which present a clump - like structure, and ( 3 ) [ oii ] $ \ lambda $ 3726 and [ oii ] $ \ lambda $ 3729 showing high densities at both the [ oiii ] $ \ lambda $ 5007 lane and the h $ \ alpha $ clump. we use these measurements to constrain resolved shock models implemented in mappings v. we find our data can be reasonably well - fitted by a model which includes a plane - parallel shock with a velocity of $ 133 \ pm5 $ km / s, plus an isotropic two - dimensional gaussian component which is likely another clump of gas ionized by photons from the shocked region, and a constant background. we compare the electron density and temperature profiles as predicted by our model with those calculated using observed emission line ratios. we find different line ratios to provide inconsistent temperature maps, and the discrepancies can be attributed to observational effects caused by limited spatial resolution and projection of the shock geometry, as well as contamination of the additional gaussian component. implications on shock properties and perspectives on future ifs - based studies of ccn are discussed.
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arxiv:2312.03602
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the rapid development in designs and fabrication techniques of superconducting qubits has helped making coherence times of qubits longer. in the near future, however, the radiative decay of a qubit into its control line will be a fundamental limitation, imposing a trade - off between fast control and long lifetime of the qubit. in this work, we successfully break this trade - off by strongly coupling another superconducting qubit along the control line. this second qubit, which we call a josephson quantum filter ( jqf ), prevents the qubit from emitting microwave photons and thus suppresses its relaxation, while faithfully transmitting large - amplitude control microwave pulses due to the saturation of the quantum filter, enabling fast qubit control. we observe an improvement of the qubit relaxation time without a reduction of the rabi frequency. this device could potentially help in the realization of a large - scale superconducting quantum information processor in terms of the heating of the qubit environments and the crosstalk between qubits.
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arxiv:2002.01635
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a brief historical review is presented of progressing understanding of transverse coherent instabilities of charged particles beams in circular machines when both coulomb and wake fields are important. the paper relates to a talk given at icfa workshop on mitigation of coherent beam instabilities in particle accelerators, 23 - 27 september 2019 in zermatt, switzerland.
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arxiv:2005.10829
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knowledge - grounded dialogue is a task of generating a fluent and informative response based on both conversation context and a collection of external knowledge, in which knowledge selection plays an important role and attracts more and more research interest. however, most existing models either select only one knowledge or use all knowledge for responses generation. the former may lose valuable information in discarded knowledge, while the latter may bring a lot of noise. at the same time, many approaches need to train the knowledge selector with knowledge labels that indicate ground - truth knowledge, but these labels are difficult to obtain and require a large number of manual annotations. motivated by these issues, we propose knoformer, a dialogue response generation model based on reinforcement learning, which can automatically select one or more related knowledge from the knowledge pool and does not need knowledge labels during training. knoformer is evaluated on two knowledge - guided conversation datasets, and achieves state - of - the - art performance.
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arxiv:2108.13686
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recently, studies have shown the potential of integrating field - type iterative methods with deep learning ( dl ) techniques in solving inverse scattering problems ( isps ). in this article, we propose a novel variational born iterative network, namely, vbim - net, to solve the full - wave isps with significantly improved structural rationality and inversion quality. the proposed vbim - net emulates the alternating updates of the total electric field and the contrast in the variational born iterative method ( vbim ) by multiple layers of subnetworks. we embed the analytical calculation of the contrast variation into each subnetwork, converting the scattered field residual into an approximate contrast variation and then enhancing it by a u - net, thus avoiding the requirement of matched measurement dimension and grid resolution as in existing approaches. the total field and contrast of each layer ' s output is supervised in the loss function of vbim - net, imposing soft physical constraints on the variables in the subnetworks, which benefits the model ' s performance. in addition, we design a training scheme with extra noise to enhance the model ' s stability. extensive numerical results on synthetic and experimental data both verify the inversion quality, generalization ability, and robustness of the proposed vbim - net. this work may provide some new inspiration for the design of efficient field - type dl schemes.
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arxiv:2405.18731
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that progress is still not sufficient to meet the target of doubling the global rate of improvement in energy efficiency. " goal 11 : " make cities and human settlements inclusive, safe, resilient and sustainable " by designing sustainable cities and communities, clean technology takes parts in the architectural aspect, transportation, and city environment. for example : global fuel economy initiative ( gfei ) - relaunched to accelerate progress on decarbonizing road transport. its main goal for passenger vehicles, in line with sdg 7. 3, is to double the energy efficiency of new vehicles by 2030. this will also help mitigate climate change by reducing harmful co2 emissions. goal 13 : " take urgent action to combat climate change and its impacts * " greenhouse gas emissions have significantly impacted the climate, and this results in a rapid solution for consistently increasing emission levels. united nations held the " paris agreement " for dealing with greenhouse gas emissions mainly within countries and for finding solutions and setting goals. = = see also = = environmental science greentech ( disambiguation ) sustainable engineering wipo green = = references = = = = external links = = investing : green technology has big growth potential, los angeles times, 2011 the global cleantech innovation index 2014, by cleantech group and wwf
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https://en.wikipedia.org/wiki/Clean_technology
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the hedgehog lattice ( hl ) is a three - dimensional topological spin texture hosting a periodic array of magnetic monopoles and antimonopoles. it has been studied theoretically for noncentrosymmetric systems with the dzyaloshinskii - moriya interaction, but the stability, as well as the magnetic and topological properties, remains elusive in the centrosymmetric case. we here investigate the ground state of an effective spin model with long - range bilinear and biquadratic interactions for a centrosymmetric cubic metal by simulated annealing. we show that our model stabilizes a hl composed of two pairs of left - and right - handed helices, resulting in no net scalar spin chirality, in stark contrast to the noncentrosymmetric case. we find that the hl turns into topologically - trivial conical states in an applied magnetic field. from the detailed analyses of the constituent spin helices, we clarify that the ellipticity and angles of the helical planes change gradually while increasing the magnetic field. we discuss the results in comparison with the experiments for a centrosymmetric cubic metal srfeo $ _ 3 $.
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arxiv:2206.03042
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social networks ' omnipresence and ease of use has revolutionized the generation and distribution of information in today ' s world. however, easy access to information does not equal an increased level of public knowledge. unlike traditional media channels, social networks also facilitate faster and wider spread of disinformation and misinformation. viral spread of false information has serious implications on the behaviors, attitudes and beliefs of the public, and ultimately can seriously endanger the democratic processes. limiting false information ' s negative impact through early detection and control of extensive spread presents the main challenge facing researchers today. in this survey paper, we extensively analyze a wide range of different solutions for the early detection of fake news in the existing literature. more precisely, we examine machine learning ( ml ) models for the identification and classification of fake news, online fake news detection competitions, statistical outputs as well as the advantages and disadvantages of some of the available data sets. finally, we evaluate the online web browsing tools available for detecting and mitigating fake news and present some open research challenges.
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arxiv:2105.10671
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the analytical expression of the magnetic field distribution within the aperture of a circular vacuum chamber due to the induced eddy is derived. two cases are discussed, one is the absence of iron, the other is that the vacuum chamber is between the iron poles, that implies the use of the image current methods. the current angular distribution in the vacuum chamber can be calculated from the ramping rate of the exposed field, then the contour integration is applied to the circular current to obtain the field distribution. the formula can be used to estimate the undesired fields from a circular beam box when it is exposed to a ramping field.
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arxiv:1910.09781
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scarcity of domain - specific data in the portuguese financial domain has disfavored the development of natural language processing ( nlp ) applications. to address this limitation, the present study advocates for the utilization of synthetic data generated through data augmentation techniques. the investigation focuses on the augmentation of a dataset sourced from the central bank of brazil faq, employing techniques that vary in semantic similarity. supervised and unsupervised tasks are conducted to evaluate the impact of augmented data on both low and high semantic similarity scenarios. additionally, the resultant dataset will be publicly disseminated on the hugging face datasets platform, thereby enhancing accessibility and fostering broader engagement within the nlp research community.
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arxiv:2311.11331
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we present a study of the inclusive production in $ p \ overline p $ collisions of the pentaquark states $ p _ c ( 4440 ) $ and $ p _ c ( 4457 ) $ with the decay to the $ j / \ psi p $ final state previously observed by the lhcb experiment. using a sample of candidates originating from decays of $ b $ - flavored hadrons, we find an enhancement in the $ j / \ psi p $ invariant mass distribution consistent with a sum of $ p _ c ( 4440 ) $ and $ p _ c ( 4457 ) $. the significance, with the input parameters set to the lhcb values, is $ 3. 0 \ sigma $. this is the first confirmatory evidence for these pentaquark states. we measure the ratio $ n _ { \ rm prompt } / n _ { \ rm nonprompt } = 0. 05 \ pm 0. 39 $ and set an upper limit of 0. 8 at the 95 \ % credibility level. the ratio of the yield of the $ p _ c ( 4312 ) $ to the sum of $ p _ c ( 4440 ) $ and $ p _ c ( 4457 ) $ is less than 0. 6 at the 95 \ % credibility level. the study is based on $ 10. 4 ~ \ rm { fb ^ { - 1 } } $ of data collected by the d0 experiment at the fermilab tevatron collider.
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arxiv:1910.11767
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direct speech - to - speech translation ( s2st ) has achieved impressive translation quality, but it often faces the challenge of slow decoding due to the considerable length of speech sequences. recently, some research has turned to non - autoregressive ( nar ) models to expedite decoding, yet the translation quality typically lags behind autoregressive ( ar ) models significantly. in this paper, we investigate the performance of ctc - based nar models in s2st, as these models have shown impressive results in machine translation. experimental results demonstrate that by combining pretraining, knowledge distillation, and advanced nar training techniques such as glancing training and non - monotonic latent alignments, ctc - based nar models achieve translation quality comparable to the ar model, while preserving up to 26. 81 $ \ times $ decoding speedup.
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arxiv:2406.07330
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the neutrino sector in a left - right extension of the standard model depends on how su ( 2 ) _ r is broken. i list all possible scenarios, including the ones where the majorana nu _ r mass is naturally much smaller than the su ( 2 ) _ r breaking scale, which is desirable for generating the proper baryon asymmetry of the universe. the best such choice is identified and discussed.
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arxiv:hep-ph/0308092
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superconducting materials find applications in a rapidly growing number of technological areas, and searching for novel superconductors continues to be a major scientific task. however, the steady increase in the complexity of candidate materials presents a big challenge to the researchers in the field. in particular, conventional experimental methods are not well suited to efficiently search for candidates in compositional space exponentially growing with the number of elements ; neither do they permit quick extraction of reliable multidimensional phase diagrams delineating the physical parameters that control superconductivity. new research paradigms that can boost the speed and the efficiency of superconducting materials research are urgently needed. high - throughput methods for rapid screening and optimization of materials have demonstrated their utility for accelerating research in bioinformatics and pharmaceutical industry, yet remain rare in quantum materials research. in this paper, we will briefly review the history of high - throughput research paradigm and then focus on some recent applications of this paradigm in superconductivity research. we consider the role these methods can play in all stages of materials development, including high - throughput computation, synthesis, characterization, and the emerging field of machine learning for materials. the high - throughput paradigm will undoubtedly become an indispensable tool of superconductivity research in the near future.
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arxiv:1912.09006
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we report on chandra x - ray observations of sn 2016jae and sn 2018cqj, both low luminosity type ia supernova that showed the presence of a h line in their early optical spectrum. no x - ray emission is detected at the location of either sn. upper limits to the luminosity of up to 2 $ \ times 10 ^ { 40 } \, $ erg s $ ^ { - 1 } $ are calculated for each sn, depending on the assumed spectral model, temperature and column density. this luminosity is comparable to that of another low - luminosity type ia sn, sn 2018fhw, that was observed with chandra. it is generally lower than upper limits calculated for type ia - csm sne observed in x - rays, and also below that of sn 2012ca, the only type ia - csm sn to have been detected in x - rays. comparisons are made to other type ia sn with a h line observed in x - rays. the observations suggest that while the density into which the sn is expanding may have been high at the time the h $ \ alpha $ line was detected, it had decreased considerably by the time of x - ray observations.
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arxiv:2407.00279
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we prove that every finite lattice l can be embedded in a three - generated finite lattice k. we also prove that every algebraic lattice with accessible cardinality is a complete sublattice of an appropriate algebraic lattice k such that k is completely generated by three elements. note that zfc has a model in which all cardinal numbers are accessible. our results strengthen p. crawley and r. a. dean ' s 1959 results by adding finiteness, algebraicity, and completeness.
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arxiv:1512.03971
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how should we present training examples to learners to teach them classification rules? this is a natural problem when training workers for crowdsourcing labeling tasks, and is also motivated by challenges in data - driven online education. we propose a natural stochastic model of the learners, modeling them as randomly switching among hypotheses based on observed feedback. we then develop strict, an efficient algorithm for selecting examples to teach to workers. our solution greedily maximizes a submodular surrogate objective function in order to select examples to show to the learners. we prove that our strategy is competitive with the optimal teaching policy. moreover, for the special case of linear separators, we prove that an exponential reduction in error probability can be achieved. our experiments on simulated workers as well as three real image annotation tasks on amazon mechanical turk show the effectiveness of our teaching algorithm.
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arxiv:1402.2092
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foundation models like clip allow zero - shot transfer on various tasks without additional training data. yet, the zero - shot performance is less competitive than a fully supervised one. thus, to enhance the performance, fine - tuning and ensembling are also commonly adopted to better fit the downstream tasks. however, we argue that such prior work has overlooked the inherent biases in foundation models. due to the highly imbalanced web - scale training set, these foundation models are inevitably skewed toward frequent semantics, and thus the subsequent fine - tuning or ensembling is still biased. in this study, we systematically examine the biases in foundation models and demonstrate the efficacy of our proposed generalized logit adjustment ( gla ) method. note that bias estimation in foundation models is challenging, as most pre - train data cannot be explicitly accessed like in traditional long - tailed classification tasks. to this end, gla has an optimization - based bias estimation approach for debiasing foundation models. as our work resolves a fundamental flaw in the pre - training, the proposed gla demonstrates significant improvements across a diverse range of tasks : it achieves 1. 5 pp accuracy gains on imagenet, an large average improvement ( 1. 4 - 4. 6 pp ) on 11 few - shot datasets, 2. 4 pp gains on long - tailed classification. codes are in \ url { https : / / github. com / beierzhu / gla }.
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arxiv:2310.08106
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recently, profile - based spoken language understanding ( slu ) has gained increasing attention, which aims to incorporate various types of supplementary profile information ( i. e., knowledge graph, user profile, context awareness ) to eliminate the prevalent ambiguities in user utterances. however, existing approaches can only separately model different profile information, without considering their interrelationships or excluding irrelevant and conflicting information within them. to address the above issues, we introduce a heterogeneous graph attention network to perform reasoning across multiple profile information, called pro - han. specifically, we design three types of edges, denoted as intra - pro, inter - pro, and utterance - pro, to capture interrelationships among multiple pros. we establish a new state - of - the - art on the proslu dataset, with an improvement of approximately 8 % across all three metrics. further analysis experiments also confirm the effectiveness of our method in modeling multi - source profile information.
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arxiv:2402.03900
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we combine radial velocities, proper motions, and low resolution abundances for a sample of 315 k and m giants in the baade ' s window ( l, b ) = ( 0. 9, - 4 ) galactic bulge field. the velocity ellipsoid of stars with [ fe / h ] > - 0. 5 dex shows a vertex deviation in the plot of radial versus transverse velocity, consistent with that expected from a population with orbits supporting a bar. we demonstrate that the significance of this vertex deviation using non - parametric rank correlation statistic is > 99 %. the velocity ellipsoid for the metal poor ( [ feh ] < - 0. 5 ) part of the population shows no vertex deviation and is consistent with an isotropic, oblate rotating population. we find no evidence for kinematic subgroups, but there is a mild tendency for the vertical velocity dispersion sigma _ b to decrease with increasing metallicity.
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arxiv:astro-ph/0611433
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the notion of ontological states is introduced here with reference to the cellular automaton interpretation of quantum mechanics proposed by g. ' t hooft. a class of discrete deterministic " hamiltonian " cellular automata is defined that has been shown to bear many features in common with continuum quantum mechanical models, however, deformed by the presence of a finite discreteness scale $ l $, such that for $ l \ rightarrow 0 $ the usual properties result - - e. g., concerning linearity, dispersion relations, multipartite systems, and superposition principle. we argue that within this class of models only very primitive realizations of ontological states and their dynamics can exist, since the equations of motion tend to produce superposition states that are not ontological. the most interesting, if not only way out seems to involve interacting multipartite systems composed of two - state " ising spins ", which evolve by a unitary transfer matrix. thus, quantum like and ontological models appear side by side here, but distinguished by second - order and first - order dynamics, respectively.
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arxiv:1711.00324
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we address the problem of the foundation of generalized ensembles in statistical physics. the approach is based on boltzmann ' s concept of orthodes. these are the statistical ensembles that satisfy the heat theorem, according to which the heat exchanged divided by the temperature is an exact differential. this approach can be seen as a mechanical approach alternative to the well established information - theoretic one based on the maximization of generalized information entropy. our starting point are the tsallis ensembles which have been previously proved to be orthodes, and have been proved to interpolate between canonical and microcanonical ensembles. here we shall see that the tsallis ensembles belong to a wider class of orthodes that include the most diverse types of ensembles. all such ensembles admit both a microcanonical - like parametrization ( via the energy ), and a canonical - like one ( via the parameter $ \ beta $ ). for this reason we name them ` ` dual ' '. one central result used to build the theory is a generalized equipartition theorem. the theory is illustrated with a few examples and the equivalence of all the dual orthodes is discussed.
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arxiv:cond-mat/0701538
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we present an eigensystem multiscale analysis for proving localization ( pure point spectrum with exponentially decaying eigenfunctions, dynamical localization ) for the anderson model in an energy interval. in particular, it yields localization for the anderson model in a nonempty interval at the bottom of the spectrum. this eigensystem multiscale analysis in an energy interval treats all energies of the finite volume operator at the same time, establishing level spacing and localization of eigenfunctions with eigenvalues in the energy interval in a fixed box with high probability. in contrast to the usual strategy, we do not study finite volume green ' s functions. instead, we perform a multiscale analysis based on finite volume eigensystems ( eigenvalues and eigenfunctions ). in any given scale we only have decay for eigenfunctions with eigenvalues in the energy interval, and no information about the other eigenfunctions. for this reason, going to a larger scale requires new arguments that were not necessary in our previous eigensystem multiscale analysis for the anderson model at high disorder, where in a given scale we have decay for all eigenfunctions.
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arxiv:1611.02650
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volume rendering is an important technique for visualizing three - dimensional scalar data grids and is commonly employed for scientific and medical image data. direct volume rendering ( dvr ) is a well established and efficient rendering algorithm for volumetric data. neural rendering uses deep neural networks to solve inverse rendering tasks and applies techniques similar to dvr. however, it has not been demonstrated successfully for the rendering of scientific volume data. in this work, we introduce deep direct volume rendering ( deepdvr ), a generalization of dvr that allows for the integration of deep neural networks into the dvr algorithm. we conceptualize the rendering in a latent color space, thus enabling the use of deep architectures to learn implicit mappings for feature extraction and classification, replacing explicit feature design and hand - crafted transfer functions. our generalization serves to derive novel volume rendering architectures that can be trained end - to - end directly from examples in image space, obviating the need to manually define and fine - tune multidimensional transfer functions while providing superior classification strength. we further introduce a novel stepsize annealing scheme to accelerate the training of deepdvr models and validate its effectiveness in a set of experiments. we validate our architectures on two example use cases : ( 1 ) learning an optimized rendering from manually adjusted reference images for a single volume and ( 2 ) learning advanced visualization concepts like shading and semantic colorization that generalize to unseen volume data. we find that deep volume rendering architectures with explicit modeling of the dvr pipeline effectively enable end - to - end learning of scientific volume rendering tasks from target images.
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arxiv:2106.05429
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we study the generalized k \ " ahler - ricci flow on complex surfaces with nondegenerate poisson structure, proving long time existence and convergence of the flow to a weak hyperk \ " ahler structure.
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arxiv:1601.02981
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to investigate the star formation process, we present a multi - wavelength study of a massive star - forming site rafgl 5085, which has been associated with the molecular outflow, hii region, and near - infrared cluster. the continuum images at 12, 250, 350, and 500 $ \ mu $ m show a central region ( having m $ _ { \ rm clump } $ $ \ sim $ 225 m $ _ { \ odot } $ ) surrounded by five parsec - scale filaments, revealing a hub - filament system ( hfs ). in the { \ it herschel } column density ( $ n ( { { \ rm { h } } } _ { 2 } ) $ ) map, filaments are identified with higher aspect ratios ( length / diameter ) and lower $ n ( { { \ rm { h } } } _ { 2 } ) $ values ( $ \ sim $ 0. 1 - - 2. 4 $ \ times $ 10 $ ^ { 21 } $ cm $ ^ { - 2 } $ ), while the central hub is found with a lower aspect ratio and higher $ n ( { { \ rm { h } } } _ { 2 } ) $ values ( $ \ sim $ 3. 5 - - 7. 0 $ \ times $ 10 $ ^ { 21 } $ cm $ ^ { - 2 } $ ). the central hub displays a temperature range of [ 19, 22. 5 ] ~ k in the { \ it herschel } temperature map, and is observed with signatures of star formation ( including radio continuum emission ). the jcmt $ ^ { 13 } $ co ( j = 3 - - 2 ) line data confirm the presence of the hfs and its hub is traced with supersonic and non - thermal motions having higher mach number and lower thermal to non - thermal pressure ratio. in the $ ^ { 13 } $ co position - velocity diagrams, velocity gradients along the filaments toward the hfs appear to be observed, suggesting the gas flow in the rafgl 5085 hfs and the applicability of the clump - fed scenario.
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arxiv:2210.04658
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artifact removal in electroencephalography ( eeg ) is a longstanding challenge that significantly impacts neuroscientific analysis and brain - computer interface ( bci ) performance. tackling this problem demands advanced algorithms, extensive noisy - clean training data, and thorough evaluation strategies. this study presents the artifact removal transformer ( art ), an innovative eeg denoising model employing transformer architecture to adeptly capture the transient millisecond - scale dynamics characteristic of eeg signals. our approach offers a holistic, end - to - end denoising solution for diverse artifact types in multichannel eeg data. we enhanced the generation of noisy - clean eeg data pairs using an independent component analysis, thus fortifying the training scenarios critical for effective supervised learning. we performed comprehensive validations using a wide range of open datasets from various bci applications, employing metrics like mean squared error and signal - to - noise ratio, as well as sophisticated techniques such as source localization and eeg component classification. our evaluations confirm that art surpasses other deep - learning - based artifact removal methods, setting a new benchmark in eeg signal processing. this advancement not only boosts the accuracy and reliability of artifact removal but also promises to catalyze further innovations in the field, facilitating the study of brain dynamics in naturalistic environments.
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arxiv:2409.07326
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the degeneracy locus of a generically symplectic poisson structure on a fano manifold is always a singular hypersurface. we prove that there exists just one family of generically symplectic poisson structures in fano manifold with cyclic picard group having a reduced simple normal crossing degeneracy locus.
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arxiv:1312.3596
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following the prediction by akaishi and yamazaki of relatively narrow $ \ bar k $ - nuclear states, deeply bound by over 100 mev where the main decay channel $ \ bar k n \ to \ pi \ sigma $ is closed, several experimental signals in stopped $ k ^ - $ reactions on light nuclei have been interpreted recently as due to such states. in this talk i review ( i ) the evidence from $ k ^ - $ - atom data for a { \ it deep } $ \ bar k $ - nucleus potential, as attractive as $ v _ { \ bar k } ( \ rho _ 0 ) \ sim - ( 150 - 200 ) $ mev at nuclear matter density, that could support such states ; and ( ii ) the theoretical arguments for a { \ it shallow } potential, $ v _ { \ bar k } ( \ rho _ 0 ) \ sim - ( 40 - 60 ) $ mev. i then review a recent work by mare \ v { s }, friedman and gal in which $ \ bar k $ - nuclear bound states are generated dynamically across the periodic table, using a rmf lagrangian that couples the $ \ bar k $ to the scalar and vector meson fields mediating the nuclear interactions. substantial polarization of the core nucleus is found for light nuclei, with central nuclear densities enhanced by almost a factor of two. the binding energies and widths calculated in this dynamical model differ appreciably from those calculated for a static nucleus. these calculations provide a lower limit of $ \ gamma _ { \ bar k } \ sim 50 \ pm 10 $ mev on the width of nuclear bound states for $ \ bar k $ binding energy in the range $ b _ { \ bar k } = 100 - 200 $ mev.
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arxiv:nucl-th/0604067
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a closed connected oriented riemannian manifold $ n $ with non - vanishing euler characteristic, non - negative curvature operator and $ 0 < 2 \ text { ric } _ n < \ text { scal } _ n $ is area - rigid in the sense that any area non - increasing spin map $ f \ colon m \ to n $ from a closed connected oriented riemannian manifold $ m $ with non - vanishing $ \ hat { a } $ - degree and $ \ text { scal } _ m \ geq \ text { scal } _ n \ circ f $ is a riemannian submersion with $ \ text { scal } _ m = \ text { scal } _ n \ circ f $. this is due to goette and semmelmann and generalizes a result by llarull. in this article, we show area - rigidity for not necessarily orientable manifolds with respect to a larger class of maps $ f \ colon m \ to n $ by replacing the topological condition on the $ \ hat { a } $ - degree by a less restrictive condition involving the so - called higher mapping degree. this includes fiber bundles over even dimensional spheres with enlargeable fibers, e. g. $ \ text { pr } _ 1 \ colon s ^ { 2n } \ times t ^ k \ to s ^ { 2n } $. we develop a technique to extract from a non - vanishing higher index a geometrically useful family of almost $ \ mathcal { d } $ - harmonic sections. this also leads to a new proof of the fact that any closed connected spin manifold with non - negative scalar curvature and non - trivial rosenberg index is ricci flat.
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arxiv:2402.05834
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this study presents an innovative approach utilising autoencoder convolutional neural networks ( aecnns ) for pneumonia detection in paediatric chest x - rays. the research addresses the complexity of pneumonia, considering diverse causative agents, including bacteria, viruses, and aspiration. autoencoder convolutional neural networks are employed to enhance anomaly detection by revealing hidden patterns in the data. the evaluation process involves meticulous analysis of the histogram reconstruction error, leading to the establishment of a threshold for anomaly identification. the results demonstrate distinct differences in error magnitudes during testing and training periods, with a threshold providing a tangible criterion for anomaly detection. the study contributes valuable insights into the discriminative capability of autoencoder convolutional neural networks, with a threshold of 0. 0127, in detecting pneumonia in paediatric chest x - rays, emphasising their potential for improving diagnostic precision.
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arxiv:2409.02142
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$ ( \ tau ^ + \ tau ^ - ) _ b $ is an atom of simple hydrogenlike structure similar to positronium $ ( e ^ + e ^ - ) _ b $ and $ ( \ mu ^ + \ mu ^ - ) _ b $. in this paper energy levels and decay widths of different decay channels of $ ( \ tau ^ + \ tau ^ - ) _ b $ are given. cross section of production of this atomic system in $ e ^ + e ^ - $ annihilation taking into account radiative corrections is calculated. according to our estimates 886 $ ( \ tau ^ + \ tau ^ - ) _ b $ atoms may be produced at bepcii and 29 $ ( \ tau ^ + \ tau ^ - ) _ b $ atoms are produced at vepp - 4m under the present experimental conditions.
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arxiv:0807.4114
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we present a reciprocal transformation which links the geng - xue equation to a particular reduction of the first negative flow of the boussinesq hierarchy. we discuss two reductions of the reciprocal transformation for the degasperis - procesi and novikov equations, respectively. with the aid of the darboux transformation and the reciprocal transformation, we obtain a compact parametric representation for the smooth soliton solutions such as multi - kink solutions of the geng - xue equation.
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arxiv:2202.03041
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the safe application of reinforcement learning ( rl ) requires generalization from limited training data to unseen scenarios. yet, fulfilling tasks under changing circumstances is a key challenge in rl. current state - of - the - art approaches for generalization apply data augmentation techniques to increase the diversity of training data. even though this prevents overfitting to the training environment ( s ), it hinders policy optimization. crafting a suitable observation, only containing crucial information, has been shown to be a challenging task itself. to improve data efficiency and generalization capabilities, we propose compact reshaped observation processing ( crop ) to reduce the state information used for policy optimization. by providing only relevant information, overfitting to a specific training layout is precluded and generalization to unseen environments is improved. we formulate three crops that can be applied to fully observable observation - and action - spaces and provide methodical foundation. we empirically show the improvements of crop in a distributionally shifted safety gridworld. we furthermore provide benchmark comparisons to full observability and data - augmentation in two different - sized procedurally generated mazes.
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arxiv:2304.13616
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a model of story generation recently proposed by riedl and young casts it as planning, with the additional condition that story characters behave intentionally. this means that characters have perceivable motivation for the actions they take. i show that this condition can be compiled away ( in more ways than one ) to produce a classical planning problem that can be solved by an off - the - shelf classical planner, more efficiently than by riedl and youngs specialised planner.
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arxiv:1401.5856
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by prior work, there is a distributed algorithm that finds a maximal fractional matching ( maximal edge packing ) in $ o ( \ delta ) $ rounds, where $ \ delta $ is the maximum degree of the graph. we show that this is optimal : there is no distributed algorithm that finds a maximal fractional matching in $ o ( \ delta ) $ rounds. our work gives the first linear - in - $ \ delta $ lower bound for a natural graph problem in the standard model of distributed computing - - - prior lower bounds for a wide range of graph problems have been at best logarithmic in $ \ delta $.
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arxiv:1304.1007
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the traditional view in numerical conformal mapping is that once the boundary correspondence function has been found, the map and its inverse can be evaluated by contour integrals. we propose that it is much simpler, and 10 - 1000 times faster, to represent the maps by rational functions computed by the aaa algorithm. to justify this claim, first we prove a theorem establishing root - exponential convergence of rational approximations near corners in a conformal map, generalizing a result of d. j. newman in 1964. this leads to the new algorithm for approximating conformal maps of polygons. then we turn to smooth domains and prove a sequence of four theorems establishing that in any conformal map of the unit circle onto a region with a long and slender part, there must be a singularity or loss of univalence exponentially close to the boundary, and polynomial approximations cannot be accurate unless of exponentially high degree. this motivates the application of the new algorithm to smooth domains, where it is again found to be highly effective.
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arxiv:1804.08127
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in this work we calculate the local elastic moduli in a weakly polydisperse 2dlennard - jones glass undergoing a quasistatic shear deformation at zero temperature. the numerical method uses coarse grained microscopic expressions for the strain, displacement and stress fields. this method allows us to calculate the local elasticity tensor and to quantify the deviation from linear elasticity ( local hooke ' s law ) at different coarse - graining scales. from the results a clear picture emerges of an amorphous material with strongly spatially heterogeneous elastic moduli that simultaneously satisfies hooke ' s law at scales larger than a characteristic length scale of the order of five interatomic distances. at this scale the glass appears as a composite material composed of a rigid scaffoldingand of soft zones. only recently calculated in non homogeneous materials, the local elastic structure plays a crucial role in the elasto - plastic response of the amorphous material. for a small macroscopic shear strain the structures associated with the non - affine displacement field appear directly related to the spatial structure of the elastic moduli. moreover for a larger macroscopic shear strain we show that zones of low shear modulus concentrate most of the strain in form of plastic rearrangements. the spatio - temporal evolution of this local elasticity map and its connection with long term dynamical heterogeneity as well as with the plasticity in the material is quantified. the possibility to use this local parameter as a predictor of subsequent local plastic activity is also discussed.
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arxiv:0906.2053
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this paper tackles the problem of finding the optimal non - coherent detector for the reacquisition of weak global navigation satellite system ( gnss ) signals in the presence of bits and phase uncertainty. two solutions are derived based on using two detection frameworks : the bayesian approach and the generalized likelihood ratio test ( glrt ). we also derive approximate detectors of reduced computation complexity and without noticeable performance degradation. simulation results reveal a clear improvement of the detection probability for the proposed techniques with respect to the conventional detectors implemented in high sensitivity gnss ( hs - gnss ) receivers to acquire weak gnss signals. finally, we draw conclusions on which is the best technique to reacquire weak gnss signals in practice considering a trade - off between performance and complexity.
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arxiv:1810.04085
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perovskite - type iridates sriro $ _ { 3 } $ and cairo $ _ { 3 } $ are a dirac line node semimetal protected by crystalline symmetry, providing an interesting playground to investigate electron correlation effects on topological semimetals. the effect of sn doping was examined by growing srir $ _ { 1 - x } $ sn $ _ { x } $ o $ _ { 3 } $ and cair $ _ { 1 - x } $ sn $ _ { x } $ o $ _ { 3 } $ thin films epitaxially on srtio $ _ { 3 } $ ( 001 ) substrate using pulsed laser deposition. upon sn doping, the semimetallic ground state switches into an insulator. as temperature is lowered, the resistivity, $ \ rho ( t ) $, of srir $ _ { 1 - x } $ sn $ _ { x } $ o $ _ { 3 } $ above a critical doping level ( $ x _ { \ text { c } } \ sim 0. 1 $ ) shows a well - defined transition from the semimetal to a weakly ferromagnetic insulator at $ t = t _ { \ text { c } } $. in contrast, the $ \ rho ( t ) $ of cair $ _ { 1 - x } $ sn $ _ { x } $ o $ _ { 3 } $ with increasing $ x $ shows a rapid increase of magnitude but does not show clear signature of metal - insulator transition in the temperature dependence. we argue that the contrasted behavior of the two closely related iridates reflects the interplay between the effects of electron correlation and disorder enhanced by sn doping.
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arxiv:1909.12544
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one of the most intriguing puzzles in hadron spectroscopy are the numerous charmonium - like states observed in the last decade, including charged states that are manifestly exotic. the $ babar $ and belle experiments have extensively studied those in b meson decays, initial state radiation processes and two photon reactions. we can question what we have understood after 11 year search in this field, and try to combine results to conclude on what these new unpredicted resonant states are, and how they can be accommodated in the theory. big effort has been made from theoretical and experimental point of view, as the potential models unlikely explain the presence of so many enhancements, for mass values above the $ d \ bar d $ threshold. in this report the $ babar $ and belle results of the two invariant mass systems of $ j / \ psi \ phi $ and $ j / \ psi \ omega $ are put in comparison in a search for non - conventional charmonium states. this involves the study of the systems of $ j / \ psi k ^ + k ^ - $ and $ j / \ psi \ pi ^ + \ pi ^ - \ pi ^ 0 $, respectively. there are strong theoretical arguments in favor of the presence of hybrids or exotic states, in those invariant mass distributions. remarks on these data analyses are given, based on the $ babar $ and belle experimental results.
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arxiv:1411.0720
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in the geometric transportation problem, we are given a collection of points $ p $ in $ d $ - dimensional euclidean space, and each point is given a supply of $ \ mu ( p ) $ units of mass, where $ \ mu ( p ) $ could be a positive or a negative integer, and the total sum of the supplies is $ 0 $. the goal is to find a flow ( called a transportation map ) that transports $ \ mu ( p ) $ units from any point $ p $ with $ \ mu ( p ) > 0 $, and transports $ - \ mu ( p ) $ units into any point $ p $ with $ \ mu ( p ) < 0 $. moreover, the flow should minimize the total distance traveled by the transported mass. the optimal value is known as the transportation cost, or the earth mover ' s distance ( from the points with positive supply to those with negative supply ). this problem has been widely studied in many fields of computer science : from theoretical work in computational geometry, to applications in computer vision, graphics, and machine learning. in this work we study approximation algorithms for the geometric transportation problem. we give an algorithm which, for any fixed dimension $ d $, finds a $ ( 1 + \ varepsilon ) $ - approximate transportation map in time nearly - linear in $ n $, and polynomial in $ \ varepsilon ^ { - 1 } $ and in the logarithm of the total supply. this is the first approximation scheme for the problem whose running time depends on $ n $ as $ n \ cdot \ mathrm { polylog } ( n ) $. our techniques combine the generalized preconditioning framework of sherman, which is grounded in continuous optimization, with simple geometric arguments to first reduce the problem to a minimum cost flow problem on a sparse graph, and then to design a good preconditioner for this latter problem.
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arxiv:1902.08384
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we discuss the various post - main sequence phases of massive stars, focusing on wolf - rayet stars, luminous blue variables, plus connections with other early - type and late - type supergiants. end states for massive stars are also investigated, emphasising connections between supernovae originating from core - collapse massive stars and gamma ray bursts.
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arxiv:astro-ph/0305141
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in this paper, we build on the techniques developed in albrecher et al. ( 2013 ), to generate initial - boundary value problems for ruin probabilities of surplus - dependent premium risk processes, under a renewal case scenario, erlang ( 2 ) claim arrivals, and an exponential claims scenario, erlang ( 2 ) claim sizes. applying the approximation theory of solutions of linear ordinary differential equations developed in fedoryuk ( 1993 ), we derive the asymptotics of the ruin probabilities when the initial reserve tends to infinity. when considering premiums that are { \ it linearly } dependent on reserves, representing for instance returns on risk - free investments of the insurance capital, we firstly derive explicit formulas for the ruin probabilities, from which we can easily determine their asymptotics, only to match the ones obtained for general premiums dependent on reserves. we compare them with the asymptotics of the equivalent ruin probabilities when the premium rate is fixed over time, to measure the gain generated by this additional mechanism of binding the premium rates with the amount of reserve own by the insurance company.
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arxiv:2101.03335
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let claw be the graph $ k _ { 1, 3 } $. a graph $ g $ on $ n \ geq 3 $ vertices is called \ emph { o } - heavy if each induced claw of $ g $ has a pair of end - vertices with degree sum at least $ n $, and 1 - heavy if at least one end - vertex of each induced claw of $ g $ has degree at least $ n / 2 $. in this note, we show that every 2 - connected $ o $ - heavy or 3 - connected 1 - heavy graph is hamiltonian if we restrict fan - type degree condition or neighborhood intersection condition to certain pairs of vertices in some small induced subgraphs of the graph. our results improve or extend previous results of broersma et al., chen et al., fan, goodman & hedetniemi, gould & jacobson, and shi on the existence of hamilton cycles in graphs.
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arxiv:1212.6466
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we introduce a new type of the spacetime quantization based on the spinorial description suggested by loop quantum gravity. specifically, we build our theory on a string theory inspired $ spin ( 3, 1 ) $ worldsheet action. because of its connection with quantum gravity theories, our proposal may in principle link back to string theory, connect to loop quantum gravity where $ su ( 2 ) $ is suggested as the fundamental symmetry, or serve as a lorentzian spin network. we derive the generalized uncertainty principle and demonstrate the holographic nature of our theory. due to the quantization of spacetime, geodesics in our theory are fuzzy, but the fuzziness is shown to be much below conceivable astrophysical bounds.
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arxiv:1606.01490
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in autonomous robot navigation, terrain cost assignment is typically performed using a semantics - based paradigm in which terrain is first labeled using a pre - trained semantic classifier and costs are then assigned according to a user - defined mapping between label and cost. while this approach is rapidly adaptable to changing user preferences, only preferences over the types of terrain that are already known by the semantic classifier can be expressed. in this paper, we hypothesize that a machine - learning - based alternative to the semantics - based paradigm above will allow for rapid cost assignment adaptation to preferences expressed over new terrains at deployment time without the need for additional training. to investigate this hypothesis, we introduce and study pacer, a novel approach to costmap generation that accepts as input a single birds - eye view ( bev ) image of the surrounding area along with a user - specified preference context and generates a corresponding bev costmap that aligns with the preference context. using both real and synthetic data along with a combination of proposed training tasks, we find that pacer is able to adapt quickly to new user preferences while also exhibiting better generalization to novel terrains compared to both semantics - based and representation - learning approaches.
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arxiv:2410.23488
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we present a systematic study of jet measurements in pp, p - - pb and pb - - pb collisions using the alice detector at the lhc. jet production cross sections are measured in pp collisions at $ \ sqrt { s } $ = 2. 76 and 7 ~ tev, in p - - pb collisions at $ \ sqrt { s _ { \ rm nn } } $ = 5. 02 ~ tev and in pb - - pb collisions at $ \ sqrt { s _ { \ rm nn } } $ = 2. 76 ~ tev. jet shape observables and fragmentation distributions are measured in pp collisions at 7 ~ tev. jets are reconstructed at midrapidity in a wide range of transverse momentum using sequential recombination jet finding algorithms ( $ k _ { \ rm t } $, anti - $ k _ { \ rm t } $, and siscone ) with several values of jet resolution parameter $ r $ in the range 0. 2 - - 0. 6. measurements are compared to next - to - leading order ( nlo ) perturbative quantum chromodynamics ( pqcd ) calculations and predictions from monte carlo ( mc ) event generators such as pythia, phojet and herwig. jet production cross sections are well reproduced by nlo pqcd calculations in pp collisions at $ \ sqrt { s } $ ~ = ~ 2. 76 ~ tev. mc models could not explain the jet cross sections in pp collisions at $ \ sqrt { s } $ = 7 tev, whereas jet shapes and fragmentation distributions are rather well reproduced by these models. the jet nuclear modification factor $ r _ { \ rm ppb } $ in p - - pb collisions is found to be consistent with unity indicating the absence of large modifications of the initial parton distribution or strong final state effects on jet production, whereas a large jet suppression is observed in pb - - pb central events with respect to peripheral events indicating formation of a dense medium in central pb - - pb events.
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arxiv:1601.04462
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we report the manifestation of field - induced berezinskii - kosterlitz - thouless ( bkt ) correlations in the weakly coupled spin - 1 / 2 heisenberg layers of the molecular - based bulk material [ cu ( pz ) $ _ 2 $ ( 2 - hopy ) $ _ 2 $ ] ( pf $ _ 6 $ ) $ _ 2 $. due to the moderate intralayer exchange coupling of $ j / k _ \ mathrm { b } = 6. 8 $ k, the application of laboratory magnetic fields induces a substantial $ xy $ anisotropy of the spin correlations. crucially, this provides a significant bkt regime, as the tiny interlayer exchange $ j ^ \ prime / k _ \ mathrm { b } \ approx 1 $ mk only induces 3d correlations upon close approach to the bkt transition with its exponential growth in the spin - correlation length. we employ nuclear magnetic resonance and $ \ mu ^ { + } $ sr measurements to probe the spin correlations that determine the critical temperatures of the bkt transition as well as that of the onset of long - range order. further, we perform stochastic series expansion quantum monte carlo simulations based on the experimentally determined model parameters. finite - size scaling of the in - plane spin stiffness yields excellent agreement of critical temperatures between theory and experiment, providing clear evidence that the nonmonotonic magnetic phase diagram of [ cu ( pz ) $ _ 2 $ ( 2 - hopy ) $ _ 2 $ ] ( pf $ _ 6 $ ) $ _ 2 $ is determined by the field - tuned $ xy $ anisotropy and the concomitant bkt physics.
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arxiv:2209.11085
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fourteen linguistically - motivated numerical indicators are evaluated for their ability to categorize verbs as either states or events. the values for each indicator are computed automatically across a corpus of text. to improve classification performance, machine learning techniques are employed to combine multiple indicators. three machine learning methods are compared for this task : decision tree induction, a genetic algorithm, and log - linear regression.
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arxiv:cmp-lg/9709002
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we have calculated evolution of neutron star binaries towards the coalescence driven by gravitational radiation. the hydrodynamical effects as well as the general relativistic effects are important in the final phase. all corrections up to post $ ^ { 2. 5 } $ - newtonian order and the tidal effect are included in the orbital motion. the star is approximated by a simple newtonian stellar model called affine star model. stellar spins and angular momentum are assumed to be aligned. we have showed how the internal stellar structure affects the stellar deformation, variations of the spins, and the orbital motion of the binary just before the contact. the gravitational wave forms from the last a few revolutions significantly depend on the stellar structure.
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arxiv:gr-qc/9610032
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the detection of 200 - 1000 mev neutrons requires large amounts, $ \ sim $ 100 cm, of detector material because of the long nuclear interaction length of these particles. in the example of the neuland neutron time - of - flight detector at fair, this is accomplished by using 3000 monolithic scintillator bars of 270 $ \ times $ 5 $ \ times $ 5 cm $ ^ 3 $ size made of a fast plastic. each bar is read out on the two long ends, and the needed time resolution of $ \ sigma _ t $ $ < $ 150 ps is reached with fast timing photomultipliers. in the present work, it is investigated whether silicon photomultiplier ( sipm ) photosensors can be used instead. experiments with a picosecond laser system were conducted to determine the timing response of the assembly made up of sipm and preamplifier. the response of the full system including also the scintillator was studied using 30 mev single electrons provided by the elbe superconducting electron linac. the elbe data were matched by a simple monte carlo simulation, and they were found to obey an inverse - square - root scaling law. in the electron beam tests, a time resolution of $ \ sigma _ t $ = 136 ps was reached with a pure sipm readout, well within the design parameters for neuland.
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arxiv:1601.04603
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