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a new type of solar neutron detector ( fib ) was launched onboard the space shuttle endeavour on july 16, 2009, and it began collecting data at the international space station ( iss ) on august 25, 2009. this paper summarizes the three years of observations obtained by the solar neutron detector fib until the end of july 2012. the solar neutron detector fib can determine both the energy and arrival direction of neutrons. we measured the energy spectra of background neutrons over the saa region and elsewhere, and found the typical trigger rates to be 20 counts / sec and 0. 22 counts / sec, respectively. it is possible to identify solar neutrons to within a level of 0. 028 counts / sec, provided that directional information is applied. solar neutrons were observed in association with the m - class solar flares that occurred on march 7 ( m3. 7 ) and june 7 ( m2. 5 ) of 2011. this marked the first time that neutrons were observed in m - class solar flares. a possible interpretaion of the prodcution process is provided. | arxiv:1208.0656 |
we study the quantum counterpart of the theorem on energy equipartition for classical systems. we consider a free quantum brownian particle modelled in terms of the caldeira - leggett framework : a system plus thermostat consisting of an infinite number of harmonic oscillators. by virtue of the theorem on the averaged kinetic energy $ e _ k $ of the quantum particle, it is expressed as $ e _ k = \ langle \ mathcal e _ k \ rangle $, where $ \ mathcal e _ k $ is thermal kinetic energy of the thermostat per one degree of freedom and $ \ langle... \ rangle $ denotes averaging over frequencies $ \ omega $ of thermostat oscillators which contribute to $ e _ k $ according to the probability distribution $ \ mathbb p ( \ omega ) $. we explore the impact of various dissipation mechanisms, via the drude, gaussian, algebraic and debye spectral density functions, on the characteristic features of $ \ mathbb { p } ( \ omega ) $. the role of the system - thermostat coupling strength and the memory time on the most probable thermostat oscillator frequency as well as the kinetic energy $ e _ k $ of the brownian particle is analysed. | arxiv:1904.07555 |
the nonnegative wigner function of all quantum states involved in teleportation of gaussian states using the standard continuous - variable teleportation protocol means that there is a local realistic phase - space description of the process. this includes the coherent states teleported up to now in experiments. we extend the phase - space description to teleportation of non - gaussian states using the standard protocol and conclude that teleportation of non - gaussian states with fidelity of 2 / 3 is a " gold standard " for this kind of teleportation. | arxiv:quant-ph/0401149 |
fo aqr is a bright intermediate polar that has long displayed large amplitude photometric variations corresponding to the 20. 9 min spin period of its white dwarf. between 2016 and 2020, the system suffered a series of unprecedented low - states, but recent data shows that it has now recovered to its normal optical luminosity. we compare the light curves obtained by k2 / kepler in 2014 with photometry from the tess mission obtained in 2021. we find that the spin pulse that had been the dominant feature of the light curve in 2014 is now weak over the second half the binary orbit and that a beat pulse is enhanced in the tess photometry. variations at approximately twice the spin frequency are now seen over the second half of the orbit. these photometric properties may be the new normal for fo aqr now that its white dwarf has begun to spin down. | arxiv:2210.13492 |
this paper concerns the harmonic shift - invert residual arnoldi ( hsira ) and jacobi - - davidson ( hjd ) methods as well as their refined variants rhsira and rhjd for the interior eigenvalue problem. each method needs to solve an inner linear system to expand the subspace successively. when the linear systems are solved only approximately, we are led to the inexact methods. we prove that the inexact hsira, rhsira, hjd and rhjd methods mimic their exact counterparts well when the inner linear systems are solved with only low or modest accuracy. we show that ( i ) the exact hsira and hjd expand subspaces better than the exact sira and jd and ( ii ) the exact rhsira and rhjd expand subspaces better than the exact hsira and hjd. based on the theory, we design stopping criteria for inner solves. to be practical, we present restarted hsira, hjd, rhsira and rhjd algorithms. numerical results demonstrate that these algorithms are much more efficient than the restarted standard sira and jd algorithms and furthermore the refined harmonic algorithms outperform the harmonic ones very substantially. | arxiv:1210.4658 |
proteins are the main workhorses of biological functions in a cell, a tissue, or an organism. identification and quantification of proteins in a given sample, e. g. a cell type under normal / disease conditions, are fundamental tasks for the understanding of human health and disease. in this paper, we present deepnovo, a deep learning - based tool to address the problem of protein identification from tandem mass spectrometry data. the idea was first proposed in the context of de novo peptide sequencing [ 1 ] in which convolutional neural networks and recurrent neural networks were applied to predict the amino acid sequence of a peptide from its spectrum, a similar task to generating a caption from an image. we further develop deepnovo to perform sequence database search, the main technique for peptide identification that greatly benefits from numerous existing protein databases. we combine two modules de novo sequencing and database search into a single deep learning framework for peptide identification, and integrate de bruijn graph assembly technique to offer a complete solution to reconstruct protein sequences from tandem mass spectrometry data. this paper describes a comprehensive protocol of deepnovo for protein identification, including training neural network models, dynamic programming search, database querying, estimation of false discovery rate, and de bruijn graph assembly. training and testing data, model implementations, and comprehensive tutorials in form of ipython notebooks are available in our github repository ( https : / / github. com / nh2tran / deepnovo ). | arxiv:1710.02765 |
a _ { nn } $ = - 18. 95, - 16. 0, - 22. 0, and + 18. 22 fm, respectively. the theoretical uncertainties are due to the fitting procedure and radiative corrections. our results seem to exclude the possibility of constraining a negative $ a _ { nn } $ with an uncertainty of less than $ \ sim \ pm $ 3 fm through an accurate determination of the muon capture rates, but the uncertainty on the present empirical value will not complicate the interpretation of the ( forth - coming ) experimental results for $ \ gamma ^ d $. finally, a comparison with the already available experimental data discourages the possibility of a bound $ nn $ state. | arxiv:1409.4260 |
this study examines the quantile connectedness among grain futures markets in brics and international markets, with a particular focus on the ongoing and escalating impacts of the russia - ukraine conflict. the findings reveal significant heterogeneity in spillover effects across different quantiles and market conditions. specifically, the time - varying total connectedness index ( tci ) consistently fluctuated around 95 \ % under both extreme bearish and bullish market conditions, markedly higher than in normal market conditions. moreover, across all quantile levels, the tci was higher during the pre - outbreak period than in the post - outbreak period. this systemic risk has notably decreased following the onset of the russia - ukraine conflict and the subsequent changes to the black sea grain initiative. apart from rice, u. s. grain futures maintained a dominant position as benchmarks for international grain prices, exerting substantial influence over the grain futures markets in brics throughout most of the period. finally, the study highlights that the influence of grain type and regional proximity strengthens pairwise connectedness among futures markets, with short - term spillovers being dominant and the spillover effect generally symmetric across quantiles. | arxiv:2409.19307 |
correlation boxes are hypothetical systems capable of producing the maximal algebraic violation of bell inequalities, beyond the quantum bound and without superluminal signaling. the fact that these systems show stronger correlations than those presented by maximally entangled quantum states has been regarded as a demonstration that the former are more nonlocal than the latter. by employing an alternative, consistent measure of nonlocality, we show that this conclusion is not necessarily true. in addition, we find a class of correlation boxes that are less nonlocal than the quantum singlet with respect to the clauser - horne - shimony - holt inequality, being, at the same time, more nonlocal with respect to the 3322 inequality. | arxiv:1605.04577 |
in this work we show how to calculate the equilibrium and non - equilibrium charge fluctuations in a gated normal mesoscopic conductor which is attached to one normal lead and one superconducting lead. we then consider an example where the structure is placed in a high magnetic field, such that the transport is dominated by edge states. we calculate the equilibrium and non - equilibrium charge fluctuations in the gate, for a single edge state, comparing our results to those for the same system, but with two normal leads. we then consider the specific example of a quantum point contact and calculate the charge fluctuations in the gate for more than one edge state. | arxiv:cond-mat/9911076 |
this is the second of a series of three papers which provide proofs of results announced in arxiv : 1210. 7494. in this paper we consider the gromov - hausdorff limits of metrics with cone singularities in the case when the limiting cone angle is less than 2 \ pi. we show that these are in a natrual way projective algebraic varieties. in the case when the limiting variety and the limiting divisor are smooth we show that the limiting metric also has standard cone singularities. | arxiv:1212.4714 |
we categorize general messenger and matter interactions in gauge - mediated susy breaking models by an r - parity for the messengers and study their phenomenological consequences. the new interactions may induce baryon - and lepton - number violating processes as well as flavor - changing neutral currents. bounds on the couplings from low - energy data are generally weak due to the large messenger mass suppression, except for the constraint from proton decay. the soft masses for the scalar particles receive negative corrections from the new interactions. consequently, in certain region of susy parameter space the \ mu - parameter is greatly reduced. the pattern of radiative electroweak symmetry breaking, susy particle mass spectrum and decay channels are also affected, leading to observable experimental signature at the current and future colliders. | arxiv:hep-ph/9802422 |
we present the conformal freeze - in ( cofi ) scenario for dark matter production. at high energies, the dark sector is described by a gauge theory flowing towards a banks - zaks fixed point, coupled to the standard model via a non - renormalizable portal interaction. at the time when the dark sector is populated in the early universe, it is described by a strongly coupled conformal field theory. as the universe cools, cosmological phase transitions in the standard model sector, either electroweak or qcd, induce conformal symmetry breaking and confinement in the dark sector. one of the resulting dark bound states is stable on the cosmological time scales and plays the role of dark matter. with the higgs portal, the cofi scenario provides a viable dark matter candidate with mass in a phenomenologically interesting 0. 1 - 1 mev range. with the quark portal, a dark matter candidate with mass around 1 kev is consistent with observations. conformal bootstrap puts a non - trivial constraint on model building in this case. | arxiv:1910.10160 |
in recent years, non - hermitian quantum physics has gained a lot in popularity in the quantum optics and condensed matter communities in order to model quantum systems with varying symmetries. in this paper, we identify a non - standard inner product that implies bosonic commutator relations for local electric and magnetic field observables and leads to a natural local biorthogonal description of the quantised electromagnetic field. when comparing this description with an alternative local hermitian description, in which the states of local photonic particles - i. e. of so - called bosons localised in position ( blips ) - are orthogonal under the conventional hermitian inner product, we find that there is an equivalence between the two approaches. careful consideration needs to be given to the physical interpretation of the different descriptions. whether a hermitian or a non - hermitian approach is more suitable depends on the circumstances that we want to model. | arxiv:2208.01532 |
we reanalyze data of heao1 / a2 - - cosmic x - ray experiment - - in order to repeat the measurements of the cosmic x - ray background ( cxb ) intensity and accurately compare this value with other measurements of the cxb. we used the data of med, hed1 and hed3 detectors in scan mode, that allowed us to measure effective solid angles and effective areas of detectors self consistently, in the same mode as the cxb intensity was measured. we obtained the average value of the cxb intensity is 1. 96 + / - 0. 10 x10 ^ { - 11 } erg / s / cm2 / deg2 in the energy band 2 - 10 kev, or 9. 7 + / - 0. 5 phot / s / cm2 / sr at 1 kev assuming the power law spectral shape with photon index gamma = 1. 4 in this energy band. we compare the obtained measurements with those obtained by different instruments over last decades. | arxiv:astro-ph/0412304 |
$ - freeness, we tend to get a small size non - induced [ induced ] $ p $ - saturating family. | arxiv:2003.04282 |
although it is well known that exploration plays a key role in reinforcement learning ( rl ), prevailing exploration strategies for continuous control tasks in rl are mainly based on naive isotropic gaussian noise regardless of the causality relationship between action space and the task and consider all dimensions of actions equally important. in this work, we propose to conduct interventions on the primal action space to discover the causal relationship between the action space and the task reward. we propose the method of state - wise action refined ( swar ), which addresses the issue of action space redundancy and promote causality discovery in rl. we formulate causality discovery in rl tasks as a state - dependent action space selection problem and propose two practical algorithms as solutions. the first approach, td - swar, detects task - related actions during temporal difference learning, while the second approach, dyn - swar, reveals important actions through dynamic model prediction. empirically, both methods provide approaches to understand the decisions made by rl agents and improve learning efficiency in action - redundant tasks. | arxiv:2201.00354 |
temporal variability of narrow absorption lines in high - resolution spectra of type ia supernovae ( sne ia ) is studied to search for circumstellar matter. time series which resolve the profiles of absorption lines such as na i d or ca ii h & k are expected to reveal variations due to photoionisation and subsequent recombination of the gases. the presence, composition, and geometry of circumstellar matter may hint at the elusive progenitor system of sne ia and could also affect the observed reddening law. to date, there are few known cases of time - varying na i d absorption in sne ia, all of which occurred during relatively late phases of the supernova evolution. photoionisation, however, is predicted to occur during the early phases of sne ia, when the supernova peaks in the ultraviolet. we therefore attempt to observe early - time absorption - line variations by obtaining high - resolution spectra of sne before maximum light. we have obtained photometry and high - resolution spectroscopy of sne ia 2013gh and iptf 13dge, to search for absorption - line variations. furthermore, we study interstellar absorption features in relation to the observed photometric colours of the sne. results. both sne display deep na i d and ca ii h & k absorption features. furthermore, small but significant variations are detected in a feature of the na i d profile of sn 2013gh. the variations are consistent with either geometric effects of rapidly moving or patchy gas clouds or photoionisation of na i gas at r \ approx 1019 cm from the explosion. our analysis indicates that it is necessary to focus on early phases to detect photoionisation effects of gases in the circumstellar medium of sne ia. different absorbers such as na i and ca ii can be used to probe for matter at different distances from the sne. | arxiv:1605.01738 |
data - enabled predictive control ( deepc ) has garnered significant attention for its ability to achieve safe, data - driven optimal control without relying on explicit system models. traditional deepc methods use pre - collected input / output ( i / o ) data to construct hankel matrices for online predictive control. however, in systems with evolving dynamics or insufficient pre - collected data, incorporating real - time data into the deepc framework becomes crucial to enhance control performance. this paper proposes an online deepc framework for time - varying systems ( i. e., systems with evolving dynamics ), enabling the algorithm to update the hankel matrix online by adding real - time informative signals. by exploiting the minimum non - zero singular value of the hankel matrix, the developed online deepc selectively integrates informative data and effectively captures evolving system dynamics. additionally, a numerical singular value decomposition technique is introduced to reduce the computational complexity for updating a reduced - order hankel matrix. simulation results on two cases, a linear time - varying system and the vehicle anti - rollover control, demonstrate the effectiveness of the proposed online reduced - order deepc framework. | arxiv:2407.16066 |
we study the twisted index of 4d $ \ mathcal { n } $ = 2 class s theories on a closed hyperbolic 3 - manifold $ m _ 3 $. via 6d picture, the index can be written in terms of topological invariants called analytic torsions twisted by irreducible flat connections on the 3 - manifold. using the topological expression, we determine the full perturbative 1 / n expansion of the twisted index. the leading part nicely matches the bekestein - hawking entropy of a magnetically charged black hole in the holographic dual $ ads _ 5 $ with $ ads _ 2 \ times m _ 3 $ near - horizon. | arxiv:1907.03430 |
merging neutron star binaries are prime candidate sources for heavy r - process nucleosynthesis. the amount of heavy r - process material is consistent with the mass ejection and rates of mergers, and abundances of relic radioactive materials suggest that heavy r - process material is produced in rare events. observations of possible macronovae provide further support for this model. still, some concerns remain. one is the observation of heavy r - process elements in ultra faint dwarf ( ufd ) galaxies. the escape velocities from ufds are so small that the natal kicks, taking place at neutron stars birth, might eject such binaries from ufds. furthermore the old stellar populations of ufds requires that r - process nucleosynthesis must have taken place very early on, while it may take several gyr for compact binaries to merge. this last problem arises also within the milky way where heavy r - process materials has been observed in some low metallicity stars. we show here that since a significant fraction of neutron star binaries form with a very small proper motion those won ' t be ejected even from a ufd. furthermore, a significant fraction of these binaries merge within a few hundred myr and in some cases the merger time is even shorter than a hundred myr. this population of " rapid mergers " explains the appearance of heavy r - process material in both ufds and in the milky way. | arxiv:1607.02148 |
we define, for each subset $ s $ of primes, an $ s _ n $ - module $ lie _ n ^ s $ with interesting properties. when $ s = \ emptyset, $ this is the well - known representation $ lie _ n $ of $ s _ n $ afforded by the free lie algebra. the most intriguing case is $ s = \ { 2 \ }, $ giving a decomposition of the regular representation as a sum of { exterior } powers of modules $ lie _ n ^ { ( 2 ) }. $ this is in contrast to the theorems of poincar \ ' e - birkhoff - witt and thrall which decompose the regular representation into a sum of symmetrised $ lie $ modules. we show that nearly every known property of $ lie _ n $ has a counterpart for the module $ lie _ n ^ { ( 2 ) }, $ suggesting connections to the cohomology of configuration spaces via the character formulas of sundaram and welker, to the eulerian idempotents of gerstenhaber and schack, and to the hodge decomposition of the complex of injective words arising from hochschild homology, due to hanlon and hersh. for arbitrary $ s, $ the symmetric and exterior powers of the module $ lie _ n ^ s $ allow us to deduce schur positivity for a new class of multiplicity - free sums of power sums. | arxiv:1803.09368 |
we study the role of different spatial inhomogeneities in generating the conditions for the appearance of a superconducting diode effect in the fraunhofer pattern of wide josephson junctions. through the scattering matrix approach, we highlight the role of mirror symmetry of the junction in forbidding the diode effect in both the two - terminal and the multi - terminal case. as sources of mirror symmetry breaking, we study spatial potentials of long and short wavelength with respect to the size of the system, mimicking the effect of side gates and atomic scale disorder, respectively, as well as the geometry of the junction, and assess their impact on the diode effect. as a common trend, we observe qualitatively similar rectification patterns magnified at the nodal points of the fraunhofer pattern by destructing interference. in multi - terminal mirror - symmetric setups, we single out the phase at additional terminals as a controllable knob to tune the diode effect at the finite field. the work presents a comprehensive treatment of the role of pure spatial inhomogeneity in the emergence of a diode effect in wide junctions. | arxiv:2411.19338 |
we study a three - body system with zero - range interactions in a one - dimensional harmonic trap. the system consists of two spin - polarized fermions and a third particle which is distinct from two others ( 2 + 1 system ). first we assume that the particles have equal masses. for this case the system in the strongly and weakly interacting limits can be accurately described using wave function factorized in hyperspherical coordinates. inspired by this result we propose an interpolation ansatz for the wave function for arbitrary repulsive zero - range interactions. by comparison to numerical calculations, we show that this interpolation scheme yields an extremely good approximation to the numerically exact solution both in terms of the energies and also in the spin - resolved densities. as an outlook, we discuss the case of mass imbalanced systems in the strongly interacting limit. here we find spectra that demonstrate that the triply degenerate spectrum at infinite coupling strength of the equal mass case is in some sense a singular case as this degeneracy will be broken down to a doubly degenerate or non - degenerate ground state by any small mass imbalance. | arxiv:1411.6544 |
we apply the wigner formalism of quantum optics to study the role of the zeropoint field fluctuations in entanglement swapping produced via parametric down conversion. it is shown that the generation of mode entanglement between two initially non interacting photons is related to the quadruple correlation properties of the electromagnetic field, through the stochastic properties of the vacuum. the relationship between the process of transferring entanglement and the different zeropoint inputs at the nonlinear crystal and the bell - state analyser is emphasized. | arxiv:1311.6062 |
we have investigated molecular distributions in protoplanetary disks, adopting a disk model with a temperature gradient in the vertical direction. the model produces sufficiently high abundances of gaseous co and hco + to account for line observations of t tauri stars using a sticking probability of unity and without assuming any non - thermal desorption. in regions of radius r > 10 au, with which we are concerned, the temperature increases with increasing height from the midplane. in a warm intermediate layer, there are significant amounts of gaseous molecules owing to thermal desorption and efficient shielding of ultraviolet radiation by the flared disk. the column densities of hcn, cn, cs, h2co, hnc and hco + obtained from our model are in good agreement with the observations of dm tau, but are smaller than those of lkca15. molecular line profiles from our disk models are calculated using a 2 - dimensional non - local - thermal - equilibrium ( nlte ) molecular - line radiative transfer code for a direct comparison with observations. deuterated species are included in our chemical model. the molecular d / h ratios in the model are in reasonable agreement with those observed in protoplanetary disks. | arxiv:astro-ph/0202060 |
we calculate the thermal euclidean correlators and the spectral functions of the energy - momentum tensor for pure gauge theories, including at non - zero spatial momentum, at leading order in perturbation theory. our goal is to improve the extraction of transport properties from euclidean correlators that are computable in lattice qcd. based on our results and the predictions of hydrodynamics for the structure of the spectral functions at low frequencies, we show that the shear and bulk viscosities can advantageously be extracted from the euclidean correlators of the conserved charges, energy and momentum, at small but non - vanishing spatial momentum. the spectral functions in these channels are free of the ultraviolet $ \ omega ^ 4 $ term which represents a large background to the thermal physics encoded in the correlators of the fluxes. | arxiv:0806.3914 |
we introduce a notion of duality solution for a single or a system of transport equations in spaces of probability measures reminiscent of the viscosity solution notion for nonlinear parabolic equations. our notion of solution by duality is, under suitable assumptions, equivalent to gradient flow solutions in case the single / system of equations has this structure. in contrast, we can deal with a quite general system of nonlinear nonlocal, diffusive or not, system of pdes without any variational structure. | arxiv:2206.03968 |
goal - oriented chatbots are essential for automating user tasks, such as booking flights or making restaurant reservations. a key component of these systems is dialogue state tracking ( dst ), which interprets user intent and maintains the dialogue state. however, existing dst methods often rely on fixed ontologies and manually compiled slot values, limiting their adaptability to open - domain dialogues. we propose a novel approach that leverages instruction tuning and advanced prompt strategies to enhance dst performance, without relying on any predefined ontologies. our method enables large language model ( llm ) to infer dialogue states through carefully designed prompts and includes an anti - hallucination mechanism to ensure accurate tracking in diverse conversation contexts. additionally, we employ a variational graph auto - encoder ( vgae ) to model and predict subsequent user intent. our approach achieved state - of - the - art with a jga of 42. 57 % outperforming existing ontology - less dst models, and performed well in open - domain real - world conversations. this work presents a significant advancement in creating more adaptive and accurate goal - oriented chatbots. | arxiv:2410.22767 |
with every real polynomial $ f $, we associate a family $ \ { f _ { \ epsilon r } \ } _ { \ epsilon, r } $ of real polynomials, in explicit form in terms of $ f $ and the parameters $ \ epsilon > 0, r \ in n $, and such that $ \ vert f - f _ { \ epsilon r } \ vert _ 1 \ to 0 $ as $ \ epsilon \ to 0 $. let $ v \ subset r ^ n $ be a real algebraic set described by finitely many polynomials equations $ g _ j ( x ) = 0, j \ in j $, and let $ f $ be a real polynomial, nonnegative on $ v $. we show that for every $ \ epsilon > 0 $, there exist nonnegative scalars $ \ { \ lambda _ j ( \ epsilon ) \ } _ { j \ in j } $ such that, for all $ r $ sufficiently large, $ $ f _ { \ epsilon r } + \ sum _ { j \ in j } \ lambda _ j ( \ epsilon ) g _ j ^ 2, \ quad is a sum of squares. $ $ this representation is an obvious certificate of nonnegativity of $ f _ { \ epsilon r } $ on $ v $, and very specific in terms of the $ g _ j $ that define the set $ v $. in particular, it is valid with { \ it no } assumption on $ v $. in addition, this representation is also useful from a computation point of view, as we can define semidefinite programing relaxations to approximate the global minimum of $ f $ on a real algebraic set $ v $, or a semi - algebraic set $ k $, and again, with { \ it no } assumption on $ v $ or $ k $. | arxiv:math/0412400 |
##ncipia mathematica, which set the groundwork for physical laws that remained current until the 19th century. some modern scholars, including andrew cunningham, perry williams, and floris cohen, argue that natural philosophy is not properly called science and that genuine scientific inquiry began only with the scientific revolution. according to cohen, " the emancipation of science from an overarching entity called ' natural philosophy is one defining characteristic of the scientific revolution. " other historians of science, including edward grant, contend that the scientific revolution that blossomed in the 17th, 18th, and 19th centuries occurred when principles learned in the exact sciences of optics, mechanics, and astronomy began to be applied to questions raised by natural philosophy. grant argues that newton attempted to expose the mathematical basis of nature – the immutable rules it obeyed – and, in doing so, joined natural philosophy and mathematics for the first time, producing an early work of modern physics. the scientific revolution, which began to take hold in the 17th century, represented a sharp break from aristotelian modes of inquiry. one of its principal advances was the use of the scientific method to investigate nature. data was collected, and repeatable measurements were made in experiments. scientists then formed hypotheses to explain the results of these experiments. the hypothesis was then tested using the principle of falsifiability to prove or disprove its accuracy. the natural sciences continued to be called natural philosophy, but the adoption of the scientific method took science beyond the realm of philosophical conjecture and introduced a more structured way of examining nature. newton, an english mathematician and physicist, was a seminal figure in the scientific revolution. drawing on advances made in astronomy by copernicus, brahe, and kepler, newton derived the universal law of gravitation and laws of motion. these laws applied both on earth and in outer space, uniting two spheres of the physical world previously thought to function independently, according to separate physical rules. newton, for example, showed that the tides were caused by the gravitational pull of the moon. another of newton ' s advances was to make mathematics a powerful explanatory tool for natural phenomena. while natural philosophers had long used mathematics as a means of measurement and analysis, its principles were not used as a means of understanding cause and effect in nature until newton. in the 18th century and 19th century, scientists including charles - augustin de coulomb, alessandro volta, and michael faraday built upon newtonian mechanics by exploring electromagnetism, or the interplay of forces with positive | https://en.wikipedia.org/wiki/Natural_science |
we compute the non - factorisable $ { \ cal o } ( \ alpha _ s ^ 2 ) $ corrections to $ t $ - channel single - top quark production at the lhc. these peculiar corrections arise because of interactions between the heavy - and the light - quark lines and appear for the very first time at next - to - next - to - leading order in perturbative qcd. we find that the non - factorisable corrections change the single - top production cross section and the relevant kinematic distributions in this process by about half a percent. | arxiv:2204.05770 |
in this article we investigate the influence of nuclear effects in the production of gluinos in nuclear collisions at the lhc, and estimate the transverse momentum dependence of the nuclear ratios $ r _ { pa } = { \ frac { d \ sigma ( pa ) } { dy d ^ 2 p _ t } } / a { \ frac { d \ sigma ( pp ) } { dy d ^ 2 p _ t } } $ and $ r _ { aa } = { \ frac { d \ sigma ( aa ) } { dy d ^ 2 p _ t } } / a ^ 2 { \ frac { d \ sigma ( pp ) } { dy d ^ 2 p _ t } } $. we demonstrate that depending on the magnitude of the nuclear effects, the production of gluinos could be enhanced, compared to proton - proton collisions. the study of these observables can be useful to determine the magnitude of the shadowing and antishadowing effects in the nuclear gluon distribution. moreover, we test different sps scenarios, corresponding to different soft susy breaking mechanisms, and find that the nuclear ratios are strongly dependent on that choice. | arxiv:1101.4910 |
disease control experts inspect public health data streams daily for outliers worth investigating, like those corresponding to data quality issues or disease outbreaks. however, they can only examine a few of the thousands of maximally - tied outliers returned by univariate outlier detection methods applied to large - scale public health data streams. to help experts distinguish the most important outliers from these thousands of tied outliers, we propose a new task for algorithms to rank the outputs of any univariate method applied to each of many streams. our novel algorithm for this task, which leverages hierarchical networks and extreme value analysis, performed the best across traditional outlier detection metrics in a human - expert evaluation using public health data streams. most importantly, experts have used our open - source python implementation since april 2023 and report identifying outliers worth investigating 9. 1x faster than their prior baseline. other organizations can readily adapt this implementation to create rankings from the outputs of their tailored univariate methods across large - scale streams. | arxiv:2401.01459 |
we review our expectations in the last year before the lhc commissioning. | arxiv:0807.4841 |
we show that for a locally free action of a simply connected nilpotent lie group on a compact manifold, if every real valued cocycle is cohomologous to a constant cocycle, then the action is parameter rigid. the converse is true if the action has a dense orbit. using this, we construct parameter rigid actions of simply connected nilpotent lie groups whose lie algebras admit rational structures with graduations. this generalizes the results of dos santos [ parameter rigid actions of the heisenberg groups. ergod. th. & dynam. sys. 27 ( 2007 ), 1719 - 1735 ] concerning the heisenberg groups. | arxiv:1101.4161 |
we summarize recent results on the evolution of unpolarized parton densities and deep - inelastic structure functions in massless perturbative qcd. due to last year ' s extension of the integer - moment calculations of the three - loop splitting functions, the nnlo evolution of the parton distributions can now be performed reliably at momentum fractions x > = 10 ^ - 4, facilitating a considerably improved theoretical accuracy of their extraction from data on deep - inelastic scattering. the nnlo corrections are not dominated, at relevant values of x, by their leading small - x terms. at large x the splitting - function series converges very rapidly, hence, employing results on the three - loop coefficient functions, the structure functions can be analysed at n ^ 3lo for x > 10 ^ - 2. the resulting values for alpha _ s do not significantly change beyond nnlo, their renormalization scale dependence reaches about + - 1 % at n ^ 3lo. | arxiv:hep-ph/0107194 |
we studied screening masses in the equilibrium thermodynamics of su ( 2 ) and su ( 3 ) pure gauge theories on the lattice. at a temperature of 2 tc we found strong evidence for dimensional reduction in the non - perturbative spectrum of screening masses. mass ratios in the high temperature su ( 3 ) theory are consistent with those in the pure gauge theory in three dimensions. at the first order su ( 3 ) phase transition we report the first measurement of the true scalar screening mass. | arxiv:hep-lat/9806034 |
the switching mechanisms in artificial spin ice systems are investigated with focus on shakti and modified shakti lattices. minimum energy paths are calculated using the geodesic nudged elastic band ( gneb ) method implemented with a micromagnetic description of the system, including the internal magnetic structure of the islands and edge modulations. two switching mechanisms, uniform magnetization rotation and domain wall formation, are found to have comparable activation energy. the preference for one over the other depends strongly on the saturation magnetization and the magnetic ordering of neighboring islands. surprisingly, these mechanisms can coexist, leading to an enhanced probability of magnetization reversal. these results provide valuable insight that can help control internal magnetization switching processes in spin ice systems and help predict their thermodynamic properties. | arxiv:2503.04237 |
the relationship between elliptic ruijsenaars - schneider ( rs ) and calogero - moser ( cm ) models with sklyanin algebra is presented. lax pair representations of the elliptic rs and cm are reviewed. for n = 2 case, the eigenvalue and eigenfunction for lame equation are found by using the result of the bethe ansatz method. | arxiv:hep-th/0201211 |
on the basis of the data given in the works of different authors a criterion of phase - photometric method of measurement of energy angle of divergence has been formulated. validity of application of the obtained relations for a ray beam with an arbitrary diameter and an arbitrary shape of the wave front has been proved. advantages of the proposed phase - photometric method in comparison with the focal - spot method have been confirmed. necessity and possibility of building a standard solid angle has been proved. | arxiv:physics/0212012 |
an algorithm for digital signal analysis using convolutional neural networks ( cnn ) was developed in this work. the main objective of this algorithm is to make the analysis of experiments with active target time projection chambers more efficient. the code is divided in three steps : baseline correction, signal deconvolution and peak detection and integration. the cnns were able to learn the signal processing models with relative errors of less than 6 \ %. the analysis based on cnns provides the same results as the traditional deconvolution algorithms, but considerably more efficient in terms of computing time ( about 65 times faster ). this opens up new possibilities to improve existing codes and to simplify the analysis of the large amount of data produced in active target experiments. | arxiv:2202.12941 |
deep convolutional neural networks ( cnn ) have massively influenced recent advances in large - scale image classification. more recently, a dynamic routing algorithm with capsules ( groups of neurons ) has shown state - of - the - art recognition performance. however, the behavior of such networks in the presence of a degrading signal ( noise ) is mostly unexplored. an analytical study on different network architectures toward noise robustness is essential for selecting the appropriate model in a specific application scenario. this paper presents an extensive performance analysis of six deep architectures for image classification on six most common image degradation models. in this study, we have compared vgg - 16, vgg - 19, resnet - 50, inception - v3, mobilenet and capsulenet architectures on gaussian white, gaussian color, salt - and - pepper, gaussian blur, motion blur and jpeg compression noise models. | arxiv:1807.10108 |
a measurement of wz electroweak ( ew ) vector boson scattering is presented. the measurement is performed in the leptonic decay modes wz $ \ to $ $ \ ell \ nu \ ell ' \ ell ' $, where $ \ ell, \ ell ' = $ e, $ \ mu $. the analysis is based on a data sample of proton - proton collisions at $ \ sqrt { s } = $ 13 tev at the lhc collected with the cms detector and corresponding to an integrated luminosity of 35. 9 fb $ ^ { - 1 } $. the wz plus two jet production cross section is measured in fiducial regions with enhanced contributions from ew production and found to be consistent with standard model predictions. the ew wz production in association with two jets is measured with an observed ( expected ) significance of 2. 2 ( 2. 5 ) standard deviations. constraints on charged higgs boson production and on anomalous quartic gauge couplings in terms of dimension - eight effective field theory operators are also presented. | arxiv:1901.04060 |
dielectric interfaces are crucial to the behavior of charged membranes, from graphene to synthetic and biological lipid bilayers. understanding electrolyte behavior near these interfaces remains a challenge, especially in the case of rough dielectric surfaces. a lack of analytical solutions consigns this problem to numerical treatments. we report an analytic method for determining electrostatic potentials near curved dielectric membranes in a two - dimensional periodic ' slab ' geometry using a periodic summation of green ' s functions. this method is amenable to simulating arbitrary groups of charges near surfaces with two - dimensional deformations. we concentrate on one - dimensional undulations. we show that increasing membrane undulation increases the asymmetry of interfacial charge distributions due to preferential ionic repulsion from troughs. in the limit of thick membranes we recover results mimicking those for electrolytes near a single interface. our work demonstrates that rough surfaces generate charge patterns in electrolytes of charged molecules or mixed - valence ions. | arxiv:2311.00570 |
the boundary line between the ferromagnetic and the spin - glass phases was investigated. finite size corrections to the free energy and magnetization were calculated. the situation coincides with the case in the information theory, when the transmission rate equals to the capacity of channel. | arxiv:cond-mat/9601092 |
in this paper we survey several intersection and non - intersection phenomena appearing in the realm of symplectic topology. we discuss their implications and finally outline some new relations of the subject to algebraic geometry. | arxiv:math/0304260 |
we numerically investigate the dynamics and linear rheology of disordered systems made of patchy particles, focussing on the role of valence, temperature and bonding mechanism. we demonstrate that the dynamics is enslaved to bonding, giving rise to an activated behaviour at low temperature. by independently computing the diffusion constant and the viscosity from the simulations, we also confirm the validity of the stokes - einstein relation in valence - limited systems, with two caveats : ( i ) the diffusion constant requires a finite - size correction, at least at the intermediate density we investigate, and ( ii ) there is the onset of a breakdown that appears at the lowest temperatures considered. finally, our results show that the storage and loss moduli of mixtures of divalent and $ m $ - valent particles exhibit an apparent power - law dependence on frequency, hinting at the possibility of using the composition to finely tune the rheological response of these materials. our results compare well with literature experimental data on valence - limited dna nanostars. in addition, the wealth of data we present and analyse here will help to develop and test theoretical frameworks aimed at describing the dynamics of flexible limited - valence particles that self - assemble into disordered networks. | arxiv:2403.12665 |
in a series of papers we combined the bethe ansatz with a kinetic ( boltzmann ) equation in order to compute exactly transport properties in a luttinger liquid with an impurity. in a recent comment [ cond - mat / 9708163 ], skorik claimed that while our results were correct in linear response, there was a ` ` serious flaw ' ' in our calculation at finite voltage. we explain here why skorik ' s arguments are inappropriate, and that there is no flaw in our work [ cond - mat / 9408068 ; cond - mat / 9505031 ; cond - mat / 9503172 ]. | arxiv:cond-mat/9710205 |
let $ s $ be a rational homology complex projective plane with quotient singularities. the algebraic montgomery - yang problem conjectures that the number of singular points of $ s $ is at most three if its smooth locus is simply - connected. in this paper, we leverage results from the study of smooth 4 - manifolds, including the donaldson diagonalization theorem and heegaard floer correction terms, to establish additional conditions for $ s $. as a result, we eliminate the possibility of a rational homology complex projective plane of specific types with four singularities. moreover, we identify large families encompassing infinitely many types of singularities that satisfy the orbifold bmy inequality, a key property in algebraic geometry, yet are obstructed from being a rational homology complex projective plane due to smooth conditions. additionally, we discuss computational results related to this problem, offering new insights into the algebraic montgomery - yang problem. | arxiv:2402.04569 |
let $ c $ be a convex subset of a locally convex space. we provide optimal approximate fixed point results for sequentially continuous maps $ f \ colon c \ to \ bar { c } $. first we prove that if $ f ( c ) $ is totally bounded, then it has an approximate fixed point net. next, it is shown that if $ c $ is bounded but not totally bounded, then there is a uniformly continuous map $ f \ colon c \ to c $ without approximate fixed point nets. we also exhibit an example of a sequentially continuous map defined on a compact convex set with no approximate fixed point sequence. in contrast, it is observed that every affine ( not - necessarily continuous ) self - mapping a bounded convex subset of a topological vector space has an approximate fixed point sequence. moreover, it is constructed a affine sequentially continuous map from a compact convex set into itself without fixed points. | arxiv:1206.3544 |
we study competition between different phases in a strongly correlated nano - structure with an edge. making use of the self - consistent green ' s function and density matrix renormalization group methods, we study a system described by the t - jz and t - j models on a strip of a square lattice with a linear hole density n _ | |. at intermediate interaction strength j / t we find edge stripe - like states, reminiscent of the bulk stripes that occur at smaller j / t. we find that stripes attach to edges more readily than hole pairs, and that the edge stripes can exhibit a peculiar phase separation. | arxiv:cond-mat/0401616 |
the potential of deploying large - scale antenna arrays in future wireless systems has stimulated extensive research on hybrid transceiver designs aiming to approximate the optimal fully - digital schemes with much reduced hardware cost and signal processing complexity. generally, this hybrid transceiver structure requires a joint design of analog and digital processing to enable both beamsteering and spatial multiplexing gains. in this paper, we develop various weighted mean - square - error minimization ( wmmse ) based hybrid transceiver designs over multiple - input multiple - output ( mimo ) interference channels at both millimeter wave ( mmwave ) and microwave frequencies. firstly, a heuristic joint design of hybrid precoder and combiner using alternating optimization is proposed, in which the majorization - minimization ( mm ) method is utilized to design the analog precoder and combiner with unit - modulus constraints. it is validated that this scheme achieves the comparable performance to the wmmse fully - digital solution. to further reduce the complexity, a phase projection - based two - stage scheme is proposed to decouple the designs of analog and digital precoder combiner. secondly, inspired by the fully - digital solutions based on the block - diagonalization zero - forcing ( bd - zf ) and signal - to - leakage - plus - noise ratio ( slnr ) criteria, low - complexity mmbased bd - zf and slnr hybrid designs are proposed to well approximate the corresponding fully - digital solutions. thirdly, the partially - connected hybrid structure for reducing system hardware cost and power consumption is considered, for which the mm - based alternating optimization still works. numerical results demonstrate the similar or superior performance of all the above proposed schemes over the existing benchmarks. | arxiv:1911.05906 |
a search is presented for hadronic signatures of beyond the standard model ( bsm ) physics, with an emphasis on signatures of a strongly - coupled hidden dark sector accessed via resonant production of a $ z ' $ mediator. the atlas experiment dataset collected at the large hadron collider from 2015 to 2018 is used, consisting of proton - proton collisions at $ \ sqrt { s } $ = 13 tev and corresponding to an integrated luminosity of 140 fb $ ^ { - 1 } $. the $ z ' $ mediator is considered to decay to two dark quarks, which each hadronize and decay to showers containing both dark and standard model particles, producing a topology of interacting and non - interacting particles within a jet known as ` ` semi - visible ". machine learning methods are used to select these dark showers and reject the dominant background of mismeasured multijet events, including an anomaly detection approach to preserve broad sensitivity to a variety of bsm topologies. a resonance search is performed by fitting the transverse mass spectrum based on a functional form background estimation. no significant excess over the expected background is observed. results are presented as limits on the production cross section of semi - visible jet signals, parameterized by the fraction of invisible particles in the decay and the $ z ' $ mass, and by quantifying the significance of any generic gaussian - shaped mass peak in the anomaly region. | arxiv:2505.01634 |
planetary bodies are formed by coagulation of solid dust grains in protoplanetary disks. therefore, it is crucial to constrain the physical and chemical properties of the dust grains. in this study, we measure the dust albedo at mm - wavelength, which depends on dust properties at the disk midplane. since the albedo and dust temperature are generally degenerate in observed thermal dust emission, it is challenging to determine them simultaneously. we propose to break this degeneracy by using multiple optically - thin molecular lines as a dust - albedo independent thermometer. in practice, we employ pressure - broadened co line wings that provide an exceptionally high signal - to - noise ratio as an optically thin line. we model the co $ j = 2 - 1 $ and $ 3 - 2 $ spectra observed by the atacama large millimeter / sub - millimeter array ( alma ) at the inner region ( $ r < 6 \ { \ rm au } $ ) of the tw hya disk and successfully derived the midplane temperature. combining multi - band continuum observations, we constrain the albedo spectrum at $ 0. 9 - 3 $ mm for the first time without assuming a dust opacity model. the albedo at these wavelengths is high, $ \ sim0. 5 - 0. 8 $, and broadly consistent with the ricci et al. ( 2010 ), diana, and dsharp dust models. even without assuming dust composition, we estimate the maximum grain size to be $ \ sim 340 \ \ mu m $, the power law index of the grain size distribution to be $ > - 4. 1 $, and porosity to be $ < 0. 96 $. the derived dust size may suggest efficient fragmentation with the threshold velocity of $ \ sim 0. 08 \ { \ rm m \ s ^ { - 1 } } $. we also note that the absolute flux uncertainty of $ \ sim10 \ % $ ( $ 1 \ sigma $ ) is measured and used in the analysis, which is approximately twice the usually assumed value. | arxiv:2412.10731 |
two - dimensional ( 2d ) lateral heterojunctions of transition metal dichalcogenides ( tmdcs ) have become a reality in recent years. semiconducting tmdc layers in their common h - structure have a nonzero in - plane electric polarization, which is a topological invariant. we show by means of first - principles calculations that lateral 2d heterojunctions between tmdcs with a different polarization generate one - dimensional ( 1d ) metallic states at the junction, even in cases where the different materials are joined epitaxially. the metallicity does not depend upon structural details, and is explained from the change in topological invariant at the junction. nevertheless, these 1d metals are susceptible to 1d instabilities, such as charge - and spin - density waves, making 2d tmdc heterojunctions ideal systems for studying 1d physics. | arxiv:2008.06758 |
we prove that a variation of graded - polarizable mixed hodge structure over a punctured disk with unipotent monodromy, has a limiting mixed hodge structure at the puncture ( i. e., it is admissible in the sense of [ sz ] ) which splits over $ \ r $, if and only if certain grading of the complexified weight filtration, depending smoothly on the hodge filtration, extends across the puncture. in particular, the result exactly supplements schmid ' s theorem for pure structures, which holds for the graded variation, and gives a hodge - theoretic condition for the relative monodromy weight filtration to exist. | arxiv:math/0007040 |
we show that oscillating flow of a simple fluid in both the newtonian and the non - newtonian regime can be described by a universal function of a single dimensionless scaling parameter $ \ omega \ tau $, where $ \ omega $ is the oscillation ( angular ) frequency and $ \ tau $ is the fluid relaxation - time ; geometry and linear dimension bear no effect on the flow. experimental energy dissipation data of mechanical resonators in a rarefied gas follow this universality closely in a broad linear dimension ( $ 10 ^ { - 6 } $ m $ < l < 10 ^ { - 2 } $ m ) and frequency ( $ 10 ^ 5 $ hz $ < \ omega / 2 \ pi < 10 ^ 8 $ hz ) range. our results suggest a deep connection between flows of simple and complex fluids. | arxiv:0811.3028 |
we consider a non - local tumour growth model of phase - field type, describing the evolution of tumour cells through proliferation in presence of a nutrient. the model consists of a coupled system, incorporating a non - local cahn - hilliard equation for the tumour phase variable and a reaction - diffusion equation for the nutrient. first, we establish novel regularity results for such a model, by applying maximal regularity theory in weighted $ l ^ p $ spaces. this technique enables us to prove the local existence and uniqueness of a regular solution, including also chemotaxis effects. by leveraging time - regularisation properties and global boundedness estimates, we further extend the solution to a global one. these results provide the foundation for addressing an optimal distributed control problem, aimed at identifying a suitable therapy guiding the tumour towards a predefined target. specifically, we prove the existence of an optimal therapy and, by studying the fr \ ' echet - differentiability of the control - to - state operator and introducing the adjoint system, we derive first - order necessary optimality conditions. | arxiv:2402.04204 |
in this work, a quantum dot couples to two helical edge states of a 2d topological insulator through weak tunnelings is studied. we show that if the electron interactions on the edge states are repulsive, with luttinger liquid parameter $ k < 1 $, the system flows to a stable two - channel fixed point at low temperatures. this is in contrast to the case of a quantum dot couples to two luttinger liquid leads. in the latter case, a strong electron - electron repulsion is needed, with $ k < 1 / 2 $, to reach the two - channel fixed point. this two - channel fixed point is described by a boundary sine - gordon hamiltonian with a $ k $ dependent boundary term. the impurity entropy at zero temperature is shown to be $ \ ln \ sqrt { 2k } $. the impurity specific heat is $ c \ propto t ^ { \ frac { 2 } { k } - 2 } $ when $ 2 / 3 < k < 1 $, and $ c \ propto t $ when $ k < 2 / 3 $. we also show that the linear conductance across the two helical edges has non - trivial temperature dependence as a result of the renormalization group flow. | arxiv:0904.2262 |
ancholik - ner is a linguistically diverse dataset for named entity recognition ( ner ) in bangla regional dialects, capturing variations across sylhet, chittagong, barishal, noakhali, and mymensingh. the dataset has around 17, 405 sentences, 3, 481 sentences per region. the data was collected from two publicly available datasets and through web scraping from various online newspapers, articles. to ensure high - quality annotations, the bio tagging scheme was employed, and professional annotators with expertise in regional dialects carried out the labeling process. the dataset is structured into separate subsets for each region and is available in csv format. each entry contains textual data along with identified named entities and their corresponding annotations. named entities are categorized into ten distinct classes : person, location, organization, food, animal, colour, role, relation, object, and miscellaneous. this dataset serves as a valuable resource for developing and evaluating ner models for bangla dialectal variations, contributing to regional language processing and low - resource nlp applications. it can be utilized to enhance ner systems in bangla dialects, improve regional language understanding, and support applications in machine translation, information retrieval, and conversational ai. | arxiv:2502.11198 |
the effect of some properties of twisted groups on the associated algebras, particularly cayley - dickson and clifford algebras. it is conjectured that the hilbert space of square - summable sequences is a cayley - dickson algebra. | arxiv:1107.1375 |
detecting and localizing anomalies in cyber - physical systems ( cps ) has become increasingly challenging as systems grow in complexity, particularly due to varying sensor reliability and node failures in distributed environments. while federated learning ( fl ) provides a foundation for distributed model training, existing approaches often lack mechanisms to address these cps - specific challenges. this paper introduces an enhanced fl framework with three key innovations : adaptive model aggregation based on sensor reliability, dynamic node selection for resource optimization, and weibull - based checkpointing for fault tolerance. the proposed framework ensures reliable condition monitoring while tackling the computational and reliability challenges of industrial cps deployments. experiments on the nasa bearing and hydraulic system datasets demonstrate superior performance compared to state - of - the - art fl methods, achieving 99. 5 % auc - roc in anomaly detection and maintaining accuracy even under node failures. statistical validation using the mann - whitney u test confirms significant improvements, with a p - value less than 0. 05, in both detection accuracy and computational efficiency across various operational scenarios. | arxiv:2501.16666 |
despite the rapid observational progress in the study of young massive star clusters, the formation of globular clusters still remains poorly understood. yet, it is emerging that globular cluster formation is intimately linked to the formation of the galaxy. i discuss a generic scenario of the cluster formation within progenitor galaxies, based on the available observational constraints. the oldest clusters formed around redshift z = 7, but the process continued at least until z = 3. because of their high density, globular clusters survived when their progenitor galaxies were disrupted by the galactic tidal field. | arxiv:astro-ph/0210556 |
quantum process tomography ( qpt ) methods aim at identifying, i. e. estimating, a quantum process. qpt is a major quantum information processing tool, since it especially allows one to experimentally characterize the actual behavior of quantum gates, that may be used as the building blocks of quantum computers. we here consider unitary, possibly dense ( i. e. without sparsity constraints ) processes, which corresponds to isolated systems. moreover, we aim at developing qpt methods that are applicable to a significant number of qubits and hence to a high state space dimension, which allows one to tackle more complex problems. using the unitarity of the process allows us to develop methods that first achieve part of qpt by performing an eigenanalysis of the estimated density matrix of a process output. building upon this idea, we first develop a class of complete algorithms that are single - stage, i. e. that use only one eigendecomposition. we then extend them to multiple - stage algorithms ( i. e. with several eigendecompositions ), in order to address high - dimensional state spaces while being less limited by the estimation errors made when using an arbitrary given quantum state tomography ( qst ) algorithm as a building block of our overall methods. we first propose two - stage methods and we then extend them to dichotomic methods, whose number of stages increases with the considered state space dimension. the relevance of our methods is validated by means of simulations. single - stage and two - stage methods first yield the following results. just running them with standard pc and software already makes it possible to evaluate their performance for up to 13 qubits, i. e. with state space dimensions up to a few thousands. this shows their attractiveness in terms of accuracy and proves that they solve the core of the dense qpt problem in a very limited time frame. for other test results, see the paper. | arxiv:2407.13542 |
in order to get the primary energy of cosmic rays from their extensive air showers using the fluorescence detection technique, the invisible energy should be added to the measured calorimetric energy. the invisible energy is the energy carried away by particles that do not deposit all their energy in the atmosphere. it has traditionally been calculated using monte carlo simulations that are dependent on the assumed primary particle mass and on model predictions for neutrino and muon production. in this work the invisible energy is obtained directly from events detected by the pierre auger observatory. the method applied is based on the correlation of the measurements of the muon number at the ground with the invisible energy of the showers. by using it, the systematic uncertainties related to the unknown mass composition and to the high energy hadronic interaction models are significantly reduced, improving in this way the estimation of the energy scale of the observatory. | arxiv:1905.04178 |
transiting planets around young stars are hard to find due to the enhanced stellar activity. only a few transiting planets have been detected around stars younger than 100 myr. we initially detected a transit - like signal in the k2 light curve of a very cool m dwarf star ( epic 211101996 ) in the pleiades open cluster, with an estimated age of about 100 myr. our detailed analysis of the per - pixel light curves, detrending with the w \ = { o } tan software and transit search with the transit least squares algorithm showed that the source of the signal is a contaminant source ( gaia dr3 66767847894609792 ) 20 " west of the target. the v - like shape of its phase - folded light curve and eclipse depth of ~ 15 % suggest that it is a grazing eclipsing binary. the contaminant has hitherto been listed as a single star, which we now identify as an eclipsing stellar binary with a period of about 6 days. | arxiv:2408.16797 |
personal variations severely limit the performance of appearance - based gaze tracking. adapting to these variations using standard neural network model adaptation methods is difficult. the problems range from overfitting, due to small amounts of training data, to underfitting, due to restrictive model architectures. we tackle these problems by introducing the spatial adaptive gaze estimator ( spaze ). by modeling personal variations as a low - dimensional latent parameter space, spaze provides just enough adaptability to capture the range of personal variations without being prone to overfitting. calibrating spaze for a new person reduces to solving a small optimization problem. spaze achieves an error of 2. 70 degrees with 9 calibration samples on mpiigaze, improving on the state - of - the - art by 14 %. we contribute to gaze tracking research by empirically showing that personal variations are well - modeled as a 3 - dimensional latent parameter space for each eye. we show that this low - dimensionality is expected by examining model - based approaches to gaze tracking. we also show that accurate head pose - free gaze tracking is possible. | arxiv:1807.00664 |
unsupervised representation learning has significantly advanced various machine learning tasks. in the computer vision domain, state - of - the - art approaches utilize transformations like random crop and color jitter to achieve invariant representations, embedding semantically the same inputs despite transformations. however, this can degrade performance in tasks requiring precise features, such as localization or flower classification. to address this, recent research incorporates equivariant representation learning, which captures transformation - sensitive information. however, current methods depend on transformation labels and thus struggle with interdependency and complex transformations. we propose self - supervised transformation learning ( stl ), replacing transformation labels with transformation representations derived from image pairs. the proposed method ensures transformation representation is image - invariant and learns corresponding equivariant transformations, enhancing performance without increased batch complexity. we demonstrate the approach ' s effectiveness across diverse classification and detection tasks, outperforming existing methods in 7 out of 11 benchmarks and excelling in detection. by integrating complex transformations like augmix, unusable by prior equivariant methods, this approach enhances performance across tasks, underscoring its adaptability and resilience. additionally, its compatibility with various base models highlights its flexibility and broad applicability. the code is available at https : / / github. com / jaemyung - u / stl. | arxiv:2501.08712 |
we show that there exist limit - periodic schr \ " odinger operators such that the associated integrated density of states is lipschitz continuous. these operators arise in the inverse spectral theoretic kam approach of p \ " oschel. | arxiv:1801.01867 |
with more intense sources of cold and ultracold neutrons becoming available and with improved experimental techniques being developed, determination of | vud | from neutron beta decay with a similar precision to that from from superallowed beta decays is within reach. determination of | vud | from neutron beta decay, free from nuclear corrections, hold the most promise for a further improvement of the determination of | vud |. the current and future neutron beta decay correlation experiments including the ucna experiment at los alamos national laboratory are reviewed | arxiv:0704.2365 |
we investigate into the rank - size distributions of urban agglomerations for india between 1981 to 2011. the incidence of a power law tail is prominent. a relevant question persists regarding the evolution of the power tail coefficient. we have developed a methodology to meaningfully track the power law coefficient over time, when a country experience population growth. a relevant dynamic law, gibrat ' s law, is empirically tested in this connection. we argue that these empirical findings for india goes in contrast with the findings in case of china, another country with population growth but monolithic political system. | arxiv:1202.3102 |
software protection aims at safeguarding assets embedded in software by preventing and delaying reverse engineering and tampering attacks. this paper presents an architecture and supporting tool flow to renew parts of native applications dynamically. renewed and diversified code and data belonging to either the original application or to linked - in protections are delivered from a secure server to a client on demand. this results in frequent changes to the software components when they are under attack, thus making attacks harder. by supporting various forms of diversification and renewability, novel protection combinations become available, and existing combinations become stronger. the prototype implementation is evaluated on a number of industrial use cases. | arxiv:2003.00916 |
the nearly continuous stream of miniature comets dominated by the kreutz sungrazers has been an unexpected bonanza for cometary science initiated by the launch of the solar and heliospheric observatory ( soho ) in 1995. over the nearly 30 years since the time, no serious attempt has been made to formulate a self - consistent model for the formation and evolution of this stream of kreutz comets - - the goal of the present two - part investigation. part i describes historical highlights of the research that has been relevant to the problem of soho sungrazers ( including the major contributions by hubbard, kreutz, and marsden ) and furnishes preliminaries of diagnostic value that are intended to facilitate, and provide critical information for, the work in part ii. formerly noted issues, such as the high frequency of close pairs in the soho database, are proposed to be products of a broader process of swarming, seen in both the nodal longitude and time. i present examples of tight swarms revealed by high arrival rates of the soho kreutz sungrazers, primarily from population i. | arxiv:2401.00845 |
, remained in use for over 300 years. zhu zaiyu, prince of zheng used 81 position abacus to calculate the square root and cubic root of 2 to 25 figure accuracy, a precision that enabled his development of the equal - temperament system. in the late 16th century, matteo ricci decided to published western scientific works in order to establish a position at the imperial court. with the assistance of xu guangqi, he was able to translate euclid ' s elements using the same techniques used to teach classical buddhist texts. other missionaries followed in his example, translating western works on special functions ( trigonometry and logarithms ) that were neglected in the chinese tradition. however, contemporary scholars found the emphasis on proofs — as opposed to solved problems — baffling, and most continued to work from classical texts alone. = = qing dynasty = = under the kangxi emperor, who learned western mathematics from the jesuits and was open to outside knowledge and ideas, chinese mathematics enjoyed a brief period of official support. at kangxi ' s direction, mei goucheng and three other outstanding mathematicians compiled a 53 - volume work titled shuli jingyun ( " the essence of mathematical study " ) which was printed in 1723, and gave a systematic introduction to western mathematical knowledge. at the same time, mei goucheng also developed to meishi congshu jiyang [ the compiled works of mei ]. meishi congshu jiyang was an encyclopedic summary of nearly all schools of chinese mathematics at that time, but it also included the cross - cultural works of mei wending ( 1633 – 1721 ), goucheng ' s grandfather. the enterprise sought to alleviate the difficulties for chinese mathematicians working on western mathematics in tracking down citations. in 1773, the qianlong emperor decided to compile the complete library of the four treasuries ( or siku quanshu ). dai zhen ( 1724 – 1777 ) selected and proofread the nine chapters on the mathematical art from yongle encyclopedia and several other mathematical works from han and tang dynasties. the long - missing mathematical works from song and yuan dynasties such as si - yuan yu - jian and ceyuan haijing were also found and printed, which directly led to a wave of new research. the most annotated works were jiuzhang suanshu xicaotushuo ( the illustrations of calculation process for the nine chapters on the mathematical art ) contributed by li huang and siyuan yujian xicao ( the detailed explanation of | https://en.wikipedia.org/wiki/Chinese_mathematics |
niobium does not show any structure transition up to very high pressures. nonetheless, by using density functional theory, we demonstrate in this work that it exhibits striking softening in elastic moduli c44 and c ' at a pressure from 20 to 150 gpa. a novel anomaly softening in c44 from 275 to 400 gpa is also predicted. the physics behind these two anomalies is elaborated by electronic structure calculations, which revealed that they are actually different, with the first one directly relates to an underlying rhombohedral distortion whereas the latter originates in an electronic topological transition. the large magnitude of the softening leads to a remarkable elastic anisotropy in both the shear and the young ' s moduli of nb. further investigation shows that thermo - electrons have an important role on these anomalies. this effect has not been noticed before. with increased electronic temperature, it is found that all anomalies ( both the elastic softening and anisotropy ) in nb are gradually diminished, effectively giving rise to a temperature - induced hardening phenomenon. | arxiv:1801.02915 |
we consider the phase diagram of the most general su ( 4 ) - symmetric two - site hamiltonian for a system of two fermions per site ( ie self - conjugate $ \ bf 6 $ representation ) on the square lattice. it is known that this model hosts magnetic phases breaking su ( 4 ) symmetry and quantum disordered dimer - like phases breaking lattice translation symmetry. motivated by a previous work [ o. gauth \ ' e, s. capponi and d. poilblanc, phys. rev. b $ \ textbf { 99 } $, 241112 ( r ) ( 2019 ) ], we investigate the possibility of the existence of su ( 4 ) quantum spin liquid phases in this model, using su ( 4 ) - symmetric projected entangled pair states ( peps ) of small bond dimensions, which can be classified according to point group and charge ( c ) symmetries. among several ( disconnected ) families of su ( 4 ) - symmetric peps, breaking or not c - symmetry, we identify critical or topological spin liquids which may be stable in some regions of the phase diagram. these results are confronted to exact diagonalisation ( ed ) and density matrix renormalisation group ( dmrg ) calculations. | arxiv:2002.05572 |
despite the many implicit references to the social aspects of search within information seeking and retrieval research, there has been relatively little work that has specifically investigated the additional requirements for collaborative search software. in this paper we re - assess a recent evaluation framework, designed for individual information seeking experiences, to see a ) how it could still be applied to collaborative search software ; b ) how it could produce additional requirements for collaborative search ; and c ) how it could be extended in future work to be even more appropriate for collaborative search evaluation. the position held after the assessment is that it can be used to evaluate collaborative search software, while providing new insights into their requirements. finally, future work will validate the frameworks applicability to collaborative search and investigate roles within collaborative groups as a means to extend the framework. | arxiv:0908.0703 |
scenario - based probabilistic forecasts have become vital for decision - makers in handling intermittent renewable energies. this paper presents a recent promising deep learning generative approach called denoising diffusion probabilistic models. it is a class of latent variable models which have recently demonstrated impressive results in the computer vision community. however, to our knowledge, there has yet to be a demonstration that they can generate high - quality samples of load, pv, or wind power time series, crucial elements to face the new challenges in power systems applications. thus, we propose the first implementation of this model for energy forecasting using the open data of the global energy forecasting competition 2014. the results demonstrate this approach is competitive with other state - of - the - art deep learning generative models, including generative adversarial networks, variational autoencoders, and normalizing flows. | arxiv:2212.02977 |
when fischler and susskind proposed a holographic prescription based on the particle horizon, they found that spatially closed cosmological models do not verify it due to the apparently unavoidable recontraction of the particle horizon area. in this article, after a short review of their original work, we expose graphically and analytically that spatially closed cosmological models can avoid this problem if they expand fast enough. it has been also shown that the holographic principle is saturated for a codimension one brane dominated universe. the fischler - susskind prescription is used to obtain the maximum number of degrees of freedom per planck volume at the planck era compatible with the holographic principle. | arxiv:0704.1637 |
three different variations of pso algorithms, i. e. canonical, gaussian bare - bone and l \ ' evy bare - bone pso, are tested to optimize the ultimate oil recovery of a large heavy oil reservoir. the performance of these algorithms was compared in terms of convergence behaviour and the final optimization results. it is found that, in general, all three types of pso methods are able to improve the objective function. the best objective function is found by using the canonical pso, while the other two methods give similar results. the gaussian bare - bone pso may picks positions that are far away from the optimal solution. the l \ ' evy bare - bone pso has similar convergence behaviour as the canonical pso. for the specific optimization problem investigated in this study, it is found that the temperature of the injection steam, co2 composition in the injection gas, and the gas injection rates have bigger impact on the objective function, while steam injection rate and the liquid production rate have less impact on the objective function. | arxiv:1306.4092 |
in this paper, we define the phases of a complex sectorial matrix to be its canonical angles, which are uniquely determined from a sectorial decomposition of the matrix. various properties of matrix phases are studied, including those of compressions, schur complements, matrix products, and sums. in particular, by exploiting a notion known as the compound numerical range, we establish a majorization relation between the phases of the eigenvalues of $ ab $ and the phases of $ a $ and $ b $. this is then applied to investigate the rank of $ i + ab $ with phase information of $ a $ and $ b $, which plays a crucial role in feedback stability analysis. a pair of problems : banded sectorial matrix completion and decomposition is studied. the phases of the kronecker and hadamard products are also discussed. | arxiv:1904.07211 |
in this paper charged black holes are obtained assuming that a born - infeld electrodynamics may arise from an interaction between the electromagnetic field and a vacuum component. in this context cauchy horizons do not appear in the maximal analytical extension once an event horizon is formed so that the interior spacetime does not suffer from any sort of instabilities which are well known in the literature. on the contrary, the causal structure exhibits an event horizon - - encapsulating a spacelike singularity - - and a cosmological horizon. we show that the strong cosmic censorship is then restored for a wide range of the parameters including configurations in which the black hole charge is much larger than its mass. we also show that the black hole thus formed described by our solution exhibits an unstable photon sphere analogous to that of the schwarzschild metric. | arxiv:2405.10293 |
performing fits to all publicly available data, we analyze the extent to which the latest results from the lhc and tevatron ( including new results presented at the rencontres de moriond ) constrain the couplings of the higgs boson - like state at ~ 125 gev, as well as possible decays into invisible particles. | arxiv:1305.4635 |
we prove that there is an finite number of friezes in type d _ n, and we provide a formula to count them. as a corollary, we obtain formulas to count the number of friezes in types b _ n, c _ n and g _ 2. we conjecture finiteness ( and precise numbers ) for other dynkin types. | arxiv:1409.3698 |
we study large - scale height fluctuations of random stepped surfaces corresponding to uniformly random lozenge tilings of polygons on the triangular lattice. for a class of polygons ( which allows arbitrarily large number of sides ), we show that these fluctuations are asymptotically governed by a gaussian free ( massless ) field. this complements the similar result obtained in kenyon [ comm. math. phys. 281 ( 2008 ) 675 - 709 ] about tilings of regions without frozen facets of the limit shape. in our asymptotic analysis we use the explicit double contour integral formula for the determinantal correlation kernel of the model obtained previously in petrov [ asymptotics of random lozenge tilings via gelfand - tsetlin schemes ( 2012 ) preprint ]. | arxiv:1206.5123 |
based on a modified expression of the rate of the convective constraint release, we present a new contour - variable model of constitutive equations in which the non - uniform segmental stretch and the non - gaussian chain statistical treatment of the single chain are considered to describe the polymer chain dynamics and the rheological behavior of an entangled system composed of linear polymer chains. the constitutive equations are solved numerically in the cases of steady shear and transient start - up of steady shear. the results indicate that the orientation and stretch, as well as the tube survival probability, have strong dependence on the chain contour variable, especially in the high - shear - rate region. however, the inclusion of the non - uniform features in the constitutive models has little modification comparing with the uniform models in determining the rheological properties both qualitatively and quantitatively. | arxiv:0907.5452 |
we investigate the stellar masses of the class of star - forming objects known as luminous compact blue galaxies ( lcbgs ) by studying a sample of galaxies in the distant cluster ms $ ~ $ 0451. 6 - 0305 at $ z \ approx0. 54 $ with ground - based multicolor imaging and spectroscopy. for a sample of 16 spectroscopically - confirmed cluster lcbgs ( colour $ b - v < 0. 5 $, surface brightness $ \ mu _ b < 21 $ mag arcsec $ ^ { - 2 } $, and magnitude $ m _ b < - 18. 5 $ ), we measure stellar masses by fitting spectral energy distribution ( sed ) models to multiband photometry, and compare with dynamical masses ( determined from velocity dispersion between 10 $ < $ $ \ sigma _ v ( \ rm km ~ s ^ { - 1 } ) $ $ < $ 80 ), we previously obtained from their emission - line spectra. we compare two different stellar population models that measure stellar mass in star - bursting galaxies, indicating correlations between the stellar age, extinction, and stellar mass derived from the two different sed models. the stellar masses of cluster lcbgs are distributed similarly to those of field lcbgs, but the cluster lcbgs show lower dynamical - to - stellar mass ratios ( $ \ rm m _ { dyn } / m _ { \ ast } = 2. 6 $ ) than their field lcbg counterparts ( $ \ rm m _ { dyn } / m _ { \ ast } = 4. 8 $ ), echoing trends noted previously in low - redshift dwarf elliptical galaxies. within this limited sample, the specific star formation rate declines steeply with increasing mass, suggesting that these cluster lcbgs have undergone vigorous star formation. | arxiv:1706.04534 |
the stability of colloidal suspensions is crucial in a wide variety of processes including the fabrication of photonic materials and scaffolds for biological assemblies. the ionic strength of the electrolyte that suspends charged colloids is widely used to control the physical properties of colloidal suspensions. the extensively used two - body derjaguin - landau - verwey - overbeek ( dlvo ) approach allows for a quantitative analysis of the effective electrostatic forces between colloidal particles. dlvo relates the ionic double - layers, which enclose the particles, to their effective electrostatic repulsion. nevertheless, the double layer is distorted at high macroion volume fractions. therefore, dlvo cannot describe the many - body effects that arise in concentrated suspensions. we show that this problem can be largely resolved by identifying effective point charges for the macroions using cell theory. this extrapolated point charge ( epc ) method assigns effective point charges in a consistent way, taking into account the excluded volume of highly charged macroions at any concentration, and thereby naturally accounting for high volume fractions in both salt - free and added - salt conditions. we provide an analytical expression for the effective pair potential and validate the epc method by comparing molecular dynamics simulations of macroions and monovalent microions that interact via coulombic potentials to simulations of macroions interacting via the derived epc effective potential. the simulations reproduce the macroion - macroion spatial correlation and the virial pressure obtained with the epc model. our findings provide a route to relate the physical properties such as pressure in systems of screened - coulomb particles to experimental measurements. | arxiv:1410.0731 |
in this paper, we fully resolve two major conjectures on odd edge - colorings and odd edge - coverings of graphs, proposed by petru { \ v { s } } evski and { \ v { s } } krekovski ( { \ it european journal of combinatorics, } 91 : 103225, 2021 ). the first conjecture states that for any loopless and connected graph $ g $ with $ \ chi _ { \ text { odd } } ' ( g ) = 4 $, there exists an edge $ e $ such that $ g \ backslash \ { e \ } $ is odd $ 3 $ - edge - colorable. the second conjecture states that any simple graph $ g $ with $ \ chi _ { \ text { odd } } ' ( g ) = 4 $ admits an odd $ 3 $ - edge - covering in which only one edge receives two or three colors. in addition, we strongly confirm the second conjecture by demonstrating that there exists an odd $ 3 $ - edge - covering in which only one edge receives two colors. | arxiv:2406.10192 |
solution combustion synthesized hole transport layer of co - doped spinel nickel cobaltite were fabricated using doctor - blading technique for planar inverted perovskite solar cells. perovskite solar cells incorporating co - doped spinel nickel cobaltite shown an increase in device performance parameters compared to un - doped spinel nickel cobaltite, leading to pce of 16. 5 %. x - ray photoelectron spectroscopy measurements revealed the tendency of cu cations to replace preferably the surface ni atoms changing the surface stoichiometry of spinel nickel cobaltite inducing a cathodic polarization. ultraviolet photoelectron spectroscopy measurements unveiled the increase of the ionization potential by 0. 1 ev for co - doped spinel nickel cobaltite film compare to undoped spinel nickel cobaltite - based hole transporting layer. we attribute the enhanced pce of inverted perovskite solar cells presented due to improved hole extraction properties of co - doped spinel nickel cobaltite hole transporting layer. | arxiv:1906.02432 |
understanding where and when human mobility is associated with disease infection is crucial for implementing location - based health care policy and interventions. previous studies on covid - 19 have revealed the correlation between human mobility and covid - 19 cases. however, the spatiotemporal heterogeneity of such correlation is not yet fully understood. in this study, we aim to identify the spatiotemporal heterogeneities in the relationship between human mobility flows and covid - 19 cases in u. s. counties. using anonymous mobile device location data, we compute an aggregate measure of mobility that includes flows within and into each county. we then compare the trends in human mobility and covid - 19 cases of each county using dynamic time warping ( dtw ). dtw results highlight the time periods and locations ( counties ) where mobility may have influenced disease transmission. also, the correlation between human mobility and infections varies substantially across geographic space and time in terms of relationship, strength, and similarity. | arxiv:2109.13765 |
we obtain results on mixing for a large class of ( not necessarily markov ) infinite measure semiflows and flows. erickson proved, amongst other things, a strong renewal theorem in the corresponding i. i. d. setting. using operator renewal theory, we extend erickson ' s methods to the deterministic ( i. e. non - i. i. d. ) continuous time setting and obtain results on mixing as a consequence. our results apply to intermittent semiflows and flows of pomeau - manneville type ( both markov and nonmarkov ), and to semiflows and flows over collet - eckmann maps with nonintegrable roof function. | arxiv:1701.08440 |
we fix any bicategory $ \ mathscr { a } $ together with a class of morphisms $ \ mathbf { w } _ { \ mathscr { a } } $, such that there is a bicategory of fractions $ \ mathscr { a } [ \ mathbf { w } _ { \ mathscr { a } } ^ { - 1 } ] $. given another such pair $ ( \ mathscr { b }, \ mathbf { w } _ { \ mathscr { b } } ) $ and any pseudofunctor $ \ mathcal { f } : \ mathscr { a } \ rightarrow \ mathscr { b } $, we find necessary and sufficient conditions in order to have an induced equivalence of bicategories from $ \ mathscr { a } [ \ mathbf { w } _ { \ mathscr { a } } ^ { - 1 } ] $ to $ \ mathscr { b } [ \ mathbf { w } _ { \ mathscr { b } } ^ { - 1 } ] $. in particular, this gives necessary and sufficient conditions in order to have an equivalence from any bicategory of fractions $ \ mathscr { a } [ \ mathbf { w } _ { \ mathscr { a } } ^ { - 1 } ] $ to any given bicategory $ \ mathscr { b } $. | arxiv:1410.6395 |
n + 1 ) } k ( l _ { k ( n ) } s ^ 0 ) $. also, we show that there is a spectral sequence \ [ h ^ s _ \ mathrm { cts } ( g _ n, \ pi _ t ( k ( e _ n ) \ otimes t ( n + 1 ) ) ) \ longrightarrow \ pi _ { t - s } ( ( k ( e _ n ) \ otimes t ( n + 1 ) ) ^ { hg _ n } ). \ ] | arxiv:2302.13533 |
the 1. 5 formalism played a key role in the discovery of supergravity and it has been used to prove the invariance of essentially all supergravity theories under local supersymmetry. it emerged from the gauging of the super poincare group to find supergravity. we review both of these developments as well as the auxiliary fields for simple supergravity and its most general coupling to matter using the tensor calculus. | arxiv:2201.06874 |
for a compact hyperk \ " ahler manifold x, we show certain zariski decomposition for every pseudo - effective r - divisor, and give a sufficient condition for x to be bimeromorphic to a ( holomorphic ) lagrangian fibration. we also prove that any sequence of d - flops between projective hyperk \ " ahler manifolds terminates after finite steps. | arxiv:0907.5311 |
a multivariate signal denoising method is proposed which employs a novel multivariate goodness of fit ( gof ) test that is applied at multiple data scales obtained from discrete wavelet transform ( dwt ). in the proposed multivariate gof test, we first utilize squared mahalanobis distance ( md ) measure to transform input multivariate data residing in m - dimensional space $ \ mathcal { r } ^ m $ to a single - dimensional space of positive real numbers $ \ mathcal { r } _ + $, i. e., $ \ mathcal { r } ^ m \ rightarrow \ mathcal { r } _ + $, where $ m > 1 $. owing to the properties of the md measure, the transformed data in $ \ mathcal { r } _ + $ follows a distinct distribution. that enables us to apply the gof test using statistic based on empirical distribution function ( edf ) on the resulting data in order to define a test for multivariate normality. we further propose to apply the above test locally on multiple input data scales obtained from discrete wavelet transform, resulting in a multivariate signal denoising framework. within the proposed method, the reference cumulative distribution function ( cdf ) is defined as a quadratic transformation of multivariate gaussian random process. consequently, the proposed method checks whether a set of dwt coefficients belong to multivariate reference distribution or not ; the coefficients belonging to the reference distribution are discarded. the effectiveness of our proposed method is demonstrated by performing extensive simulations on both synthetic and real world datasets. | arxiv:2005.11616 |
chikungunya virus ( chikv ) is one of the most relevant arboviruses affecting public health today. it belongs to the togaviridae family and alphavirus genus, causing an arthritogenic disease known as chikungunya fever ( chikf ). this multifaceted disease is distinguished from other arbovirus infections by intense arthralgia, which can persist for months or even years in some individuals. the virus has re - emerged as a global health threat in recent decades, originating in africa and spreading across asia and america, leading to widespread outbreaks affecting millions. despite more than 50 years of research on chikv pathogenesis, no drugs or vaccines are available. current management focuses on supportive care to alleviate symptoms and improve patient ' s quality of life. the ongoing threat posed by chikv highlights the need to understand its pathogenesis better. this review provides a comprehensive overview of chikv, focusing on host factors, vector - related factors, and complex viral genetic interactions. by exploring these intricate connections, we aim to offer insights that may lead to more effective strategies for preventing and managing this re - emerging global health threat. | arxiv:2411.12779 |
intensity variations in image texture can provide powerful quantitative information about physical properties of biological tissue. however, tissue patterns can vary according to the utilized imaging system and are intrinsically correlated to the scale of analysis. in the case of ultrasound, the nakagami distribution is a general model of the ultrasonic backscattering envelope under various scattering conditions and densities where it can be employed for characterizing image texture, but the subtle intra - heterogeneities within a given mass are difficult to capture via this model as it works at a single spatial scale. this paper proposes a locally adaptive 3d multi - resolution nakagami - based fractal feature descriptor that extends nakagami - based texture analysis to accommodate subtle speckle spatial frequency tissue intensity variability in volumetric scans. local textural fractal descriptors - which are invariant to affine intensity changes - are extracted from volumetric patches at different spatial resolutions from voxel lattice - based generated shape and scale nakagami parameters. using ultrasound radio - frequency datasets we found that after applying an adaptive fractal decomposition label transfer approach on top of the generated nakagami voxels, tissue characterization results were superior to the state of art. experimental results on real 3d ultrasonic pre - clinical and clinical datasets suggest that describing tumor intra - heterogeneity via this descriptor may facilitate improved prediction of therapy response and disease characterization. | arxiv:1601.03531 |
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