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of scientific revolutions, thomas kuhn argued that the process of observation and evaluation takes place within a " paradigm ", which he describes as " universally recognized achievements that for a time provide model problems and solutions to community of practitioners. " a paradigm implicitly identifies the objects and relations under study and suggests what experiments, observations or theoretical improvements need to be carried out to produce a useful result. he characterized normal science as the process of observation and " puzzle solving " which takes place within a paradigm, whereas revolutionary science occurs when one paradigm overtakes another in a paradigm shift. kurn was a historian of science, and his ideas were inspired by the study of older paradigms that have been discarded, such as aristotelian mechanics or aether theory. these had often been portrayed by historians as using " unscientific " methods or beliefs. but careful examination showed that they were no less " scientific " than modern paradigms. both were based on valid evidence, both failed to answer every possible question. a paradigm shift occurred when a significant number of observational anomalies arose in the old paradigm and efforts to resolve them within the paradigm were unsuccessful. a new paradigm was available that handled the anomalies with less difficulty and yet still covered ( most of ) the previous results. over a period of time, often as long as a generation, more practitioners began working within the new paradigm and eventually the old paradigm was abandoned. for kuhn, acceptance or rejection of a paradigm is a social process as much as a logical process. kuhn ' s position, however, is not one of relativism ; he wrote " terms like ' subjective ' and ' intuitive ' cannot be applied to [ paradigms ]. " paradigms are grounded in objective, observable evidence, but our use of them is psychological and our acceptance of them is social. = = current approaches = = = = = naturalism ' s axiomatic assumptions = = = according to robert priddy, all scientific study inescapably builds on at least some essential assumptions that cannot be tested by scientific processes ; that is, that scientists must start with some assumptions as to the ultimate analysis of the facts with which it deals. these assumptions would then be justified partly by their adherence to the types of occurrence of which we are directly conscious, and partly by their success in representing the observed facts with a certain generality, devoid of ad hoc suppositions. " kuhn also claims that all science is based on assumptions about the character of the universe, rather than | https://en.wikipedia.org/wiki/Philosophy_of_science |
this paper provides counterexamples to a previously conjectured upper bound on the first index $ n _ 0 $ at which a zero appears in constant term sequences of the form $ a _ p ( n ) = ct ( p ^ n ) \ mod p $, where $ p ( t ) \ in \ mathbb { z } [ t, t ^ { - 1 } ] $. the conjecture posited that the first zero must occur at some index $ n _ 0 < p ^ { \ text { deg } ( p ) } $. we prove an automaton state - based bound for univariate polynomials $ n _ 0 < p ^ { \ kappa ( p, p ) } $, where $ \ kappa ( p, p ) $ is the automaticity of $ ( a _ p ( n ) ) _ { n \ geq 0 } $ over $ \ mathbb { f } _ p $. we support our theoretical results with randomized experiments on low degree laurent polynomials and propose the $ \ kappa ( p, p ) $ based bound as a practical alternative to the general worst case bound arising from the rowland zeilberger construction. | arxiv:2504.19031 |
we propose a parameter optimization method for achieving static equilibrium of discrete elastic rods. our method simultaneously optimizes material stiffness and rest shape parameters under box constraints to exactly enforce zero net force while avoiding stability issues and violations of physical laws. for efficiency, we split our constrained optimization problem into primal and dual subproblems via the augmented lagrangian method, while handling the dual subproblem via simple vector updates. to efficiently solve the box - constrained primal subproblem, we propose a new active - set cholesky preconditioner. our method surpasses prior work in generality, robustness, and speed. | arxiv:2412.16461 |
one of the fundamental problems in extracting the cosmic microwave background signal ( cmb ) from millimeter / submillimeter observations is the pollution by emission from the milky way : synchrotron, free - free, and thermal dust emission. to extract the fundamental cosmological parameters from cmb signal, it is mandatory to minimize this pollution since it will create systematic errors in the cmb power spectra. in previous investigations, it has been demonstrated that the neural network method provide high quality cmb maps from temperature data. here the analysis is extended to polarization maps. as a concrete example, the wmap 7 - year polarization data, the most reliable determination of the polarization properties of the cmb, has been analysed. the analysis has adopted the frequency maps, noise models, window functions and the foreground models as provided by the wmap team, and no auxiliary data is included. within this framework it is demonstrated that the network can extract the cmb polarization signal with no sign of pollution by the polarized foregrounds. the errors in the derived polarization power spectra are improved compared to the errors derived by the wmap team. | arxiv:1202.6538 |
the objective of this paper is to minimize the energy consumption of a quantized min - sum ldpc decoder, by considering aggressive voltage downscaling of the decoder circuit. since low power supply may introduce faults in the memories used by the decoder architecture, this paper proposes to optimize the energy consumption of the faulty min - sum decoder while satisfying a given performance criterion. the proposed optimization method relies on a coordinate descent algorithm that optimizes code and decoder parameters which have a strong influence on the decoder energy consumption : codeword length, number of quantization bits, and failure probability of the memories. optimal parameter values are provided for several codes defined by their protographs, and significant energy gains are observed compared to non - optimized setups. | arxiv:2108.11812 |
we study the question of when a given countable ordinal $ \ alpha $ is $ \ sigma ^ 1 _ n $ - or $ \ pi ^ 1 _ n $ - reflecting in models which are neither $ \ mathsf { pd } $ models nor the constructible universe, focusing on generic extensions of $ l $. we prove, amongst other things, that adding any number of cohen or random reals, or forcing with sacks forcing or any lightface borel weakly homogeneous ccc forcing notion cannot change such reflection properties. moreover we show that collapse forcing increases the value of the least reflecting ordinals but, curiously, to ordinals which are still smaller than the $ \ omega _ 1 $ of $ l $. | arxiv:2311.12533 |
we construct a new, simple phenomenological model along the lines of ads / qcd. the essential new ingredient is the brane - antibrane effective action including the open string tachyon proposed by sen. chiral symmetry breaking happens because of tachyon dynamics. we fit a large number of low - spin meson masses at the 10 % - 15 % level. the only free parameters involved in the fits correspond to the overall qcd - scale and the quark masses. several aspects of previous models are qualitatively improved. | arxiv:1003.2377 |
three - dimensional thermoelastic analysis in presence of electro magnetic field is investigated of a rectangular plate. in the context of green - naghdi model - ii, fractional order energy equation is adopted for a rotating anisotropic rectangular plate which is subjected to simply supported and isothermal on its four lateral edges. normal mode analysis is adopted to the governing equations to formulate a vector - matrix differential equation. the analytical closed form solution of the vector - matrix differential equation is obtained for the physical parameters using eigen value approach methodology. numerical results are represented graphically with a sinusoidal spatial variations of the stress applied on the top surface of the plate. | arxiv:1808.07423 |
we report the first comprehensive study of emission line variability in an accreting young brown dwarf. we have collected 14 high - resolution optical spectra of 2massw j1207334 - 393254 ( m8 ), a likely member of the nearby 8 - million - year - old tw hydrae association. these spectra show a variety of emission lines that are commonly seen in classical t tauri stars. halpha line in particular shows dramatic changes in shape and intensity in our dataset, both on timescales of several weeks and several hours. in spectra from late - january, the line is relatively weak and only slightly asymmetric. spectra from mid - and late - march show intense, broad and asymmetric halpha emission, indicative of on - going disk accretion. we estimate that the accretion rate could have changed by a factor of 5 - 10 over ~ 6 weeks in this brown dwarf. march spectra also reveal significant ` quasi - periodic ' changes in the halpha line profile over the course of a night, from clearly double - peaked to nearly symmetric. these nightly profile changes, roughly consistent with the brown dwarf ' s rotation period, could be the result of a redshifted absorption feature coming into and out of our line of sight ; when the profile is double - peaked we may be looking into an accretion column, flowing from the inner disk edge on to the central object, indicating that the accretion is probably channelled along the magnetic field lines. our findings provide strong support for the magnetospheric accretion scenario, and thus for the existence of large - scale magnetic fields, in the sub - stellar regime ( abridged ). | arxiv:astro-ph/0507122 |
let $ x $ be a surface of degree $ n $, projected onto $ \ mathbb { cp } ^ 2 $. the surface has a natural galois cover with galois group $ s _ n. $ it is possible to determine the fundamental group of a galois cover from that of the complement of the branch curve of $ x. $ in this paper we survey the fundamental groups of galois covers of all surfaces of small degree $ n \ leq 4 $, that degenerate to a nice plane arrangement, namely a union of $ n $ planes such that no three planes meet in a line. we include the already classical examples of the quadric, the hirzebruch and the veronese surfaces and the degree $ 4 $ embedding of $ \ mathbb { cp } ^ 1 \ times \ mathbb { cp } ^ 1, $ and also add new computations for the remaining cases : the cubic embedding of the hirzebruch surface $ f _ 1 $, the cayley cubic ( or a smooth surface in the same family ), for a quartic surface that degenerates to the union of a triple point and a plane not through the triple point, and for a quartic $ 4 $ - point. in an appendix, we also include the degree $ 8 $ surface $ \ mathbb { cp } ^ 1 \ times \ mathbb { cp } ^ 1 $ embedded by the $ ( 2, 2 ) $ embedding, and the degree $ 2n $ surface embedded by the $ ( 1, n ) $ embedding, in order to complete the classification of all embeddings of $ \ mathbb { cp } ^ 1 \ times \ mathbb { cp } ^ 1, $ which was begun in \ cite { 15 }. | arxiv:1005.4203 |
text - to - image diffusion - based generative models have the stunning ability to generate photo - realistic images and achieve state - of - the - art low fid scores on challenging image generation benchmarks. however, one of the primary failure modes of these text - to - image generative models is in composing attributes, objects, and their associated relationships accurately into an image. in our paper, we investigate compositional attribute binding failures, where the model fails to correctly associate descriptive attributes ( such as color, shape, or texture ) with the corresponding objects in the generated images, and highlight that imperfect text conditioning with clip text - encoder is one of the primary reasons behind the inability of these models to generate high - fidelity compositional scenes. in particular, we show that ( i ) there exists an optimal text - embedding space that can generate highly coherent compositional scenes showing that the output space of the clip text - encoder is sub - optimal, and ( ii ) the final token embeddings in clip are erroneous as they often include attention contributions from unrelated tokens in compositional prompts. our main finding shows that significant compositional improvements can be achieved ( without harming the model ' s fid score ) by fine - tuning only a simple and parameter - efficient linear projection on clip ' s representation space in stable - diffusion variants using a small set of compositional image - text pairs. | arxiv:2406.07844 |
motivated by recent results of $ n $ th order muffin - tin orbital ( nmto ) implementation of the density functional theory ( dft ), we re - examine low - temperature ground - state properties of the anti - ferromagnetic insulating phase of vanadium sesquioxide v $ _ 2 $ o $ _ 3 $. the hopping matrix elements obtained by the nmto - downfolding procedure differ significantly from those previously obtained in electronic structure calculations and imply that the in - plane hopping integrals are as important as the out - of - plane ones. we use the nmto hopping matrix elements as input and perform a variational study of the ground state. we show that the formation of stable molecules throughout the crystal is not favorable in this case and that the experimentally observed magnetic structure can still be obtained in the atomic variational regime. however the resulting ground state ( two $ t _ { 2g } $ electrons occupying the degenerate $ e _ g $ doublet ) is in contrast with many well established experimental observations. we discuss the implications of this finding in the light of the non - local electronic correlations certainly present in this compound. | arxiv:0904.2757 |
the linear and nonlinear properties of the rao - dust - magnetohydrodynamic ( r - d - mhd ) waves in a dusty magnetoplasma are studied. by employing the inertialess electron equation of motion, inertial ion equation of motion, amp \ ` ere ' s law, faraday ' s law, and the continuity equation in a plasma with immobile charged dust grains, the linear and nonlinear propagation of two - dimensional r - d - mhd waves are investigated. in the linear regime, the existence of immobile dust grains produces the rao cutoff frequency, which is proportional to the dust charge density and the ion gyrofrequency. on the other hand, the dynamics of an amplitude modulated r - d - mhd waves is governed by the cubic nonlinear schroedinger equation. the latter has been derived by using the reductive perturbation technique and the two - timescale analysis which accounts for the harmonic generation nonlinearity in plasmas. the stability of the modulated wave envelope against non - resonant perturbations is studied. finally, the possibility of localized envelope excitations is discussed. | arxiv:physics/0402050 |
the discovery of supersymmetry is one of the major goals of the current experiments at the tevatron and in proposed experiments at the large hadron collider ( lhc ). however when sparticles are produced the signatures of their production will to a significant degree depend on their hierarchical mass patterns. here we investigate hierarchical mass patterns for the four lightest sparticles within one of the leading candidate theories - the sugra model. specifically we analyze the hierarchies for the four lightest sparticles for the msugra as well as for a general class of supergravity unified models including nonuniversalities in the soft breaking sector. it is shown that out of nearly $ 10 ^ 4 $ possibilities of sparticle mass hierarchies, only a small number survives the rigorous constraints of radiative electroweak symmetry breaking, relic density and other experimental constraints. the signature space of these mass patterns at the lhc is investigated using a large set of final states including multi - leptonic states, hadronically decaying $ \ tau $ s, tagged $ b $ jets and other hadronic jets. in all, we analyze more than 40 such lepton plus jet and missing energy signatures along with several kinematical signatures such as missing transverse momentum, effective mass, and invariant mass distributions of final state observables. it is shown that a composite analysis can produce significant discrimination among sparticle mass patterns allowing for a possible identification of the source of soft breaking. while the analysis given is for supergravity models, the techniques used in the analysis are applicable to wide class of models including string and brane models. | arxiv:0808.3157 |
an important part of textual inference is making deductions involving monotonicity, that is, determining whether a given assertion entails restrictions or relaxations of that assertion. for instance, the statement ' we know the epidemic spread quickly ' does not entail ' we know the epidemic spread quickly via fleas ', but ' we doubt the epidemic spread quickly ' entails ' we doubt the epidemic spread quickly via fleas '. here, we present the first algorithm for the challenging lexical - semantics problem of learning linguistic constructions that, like ' doubt ', are downward entailing ( de ). our algorithm is unsupervised, resource - lean, and effective, accurately recovering many de operators that are missing from the hand - constructed lists that textual - inference systems currently use. | arxiv:0906.2415 |
the purpose of this article is to expose and further develop a simple yet surprisingly far - reaching framework for generating monotone quantities for positive solutions to linear heat equations in euclidean space. this framework is intimately connected to the existence of a rich variety of algebraic closure properties of families of sub / super - solutions, and more generally solutions of systems of differential inequalities capturing log - convexity properties such as the li - - yau gradient estimate. various applications are discussed, including connections with the general brascamp - - lieb inequality and the ornstein - - uhlenbeck semigroup. | arxiv:1509.01949 |
exoplanet discoveries over recent years have shown that terrestrial planets are exceptionally common. many of these planets are in compact systems that result in complex orbital dynamics. a key step toward determining the surface conditions of these planets is understanding the latitudinally dependent flux incident at the top of the atmosphere as a function of orbital phase. the two main properties of a planet that influence the time - dependent nature of the flux are the obliquity and orbital eccentricity of the planet. we derive the criterion for which the flux variation due to obliquity is equivalent to the flux variation due to orbital eccentricity. this equivalence is computed for both the maximum and average flux scenarios, the latter of which includes the effects of the diurnal cycle. we apply these calculations to four known multi - planet systems ( gj 163, k2 - 3, kepler - 186, and proxima centauri ), where we constrain the eccentricity of terrestrial planets using orbital dynamics considerations and model the effect of obliquity on incident flux. we discuss the implications of these simulations on climate models for terrestrial planets and outline detectable signatures of planetary obliquity. | arxiv:1709.09240 |
current submillimetre surveys are hindered in their ability to reveal detailed information on the epoch of galaxy formation and the evolutionary history of a high - redshift starburst galaxy population. the difficulties are due to the small primary apertures ( d < 15 m ) of existing submillimetre telescopes and the limited sensitivities of their first generation of bolometer cameras. this situation is changing rapidly due to a variety of powerful new ground - based, airborne and satellite fir to millimetre wavelength facilities. improving our understanding of the luminosity and clustering evolution provides the motivation for conducting cosmological submillimetre and millimetre surveys. it is therefore important that we quantify the limitations of the future surveys and the significance of the results that can be drawn from them. in this paper we present simulated surveys which are made as realistic as possible in order to address some key issues confronting existing and forthcoming surveys. we discuss the results from simulations with a range of wavelengths ( 200 um - 1. 1 mm ), spatial resolutions ( 6 arcsec - 27 arcsec ) and flux densities ( 0. 01 - 310 mjy ). we address how the measured source - counts could be affected by resolution and confusion, by the survey sensitivity and noise, and by the sampling variance due to clustering and shot - noise. | arxiv:astro-ph/0004002 |
in this paper, we present a method for factor analysis of discrete data. this is accomplished by fitting a dependent poisson model with a factor structure. to be able to analyze ordinal data, we also consider a truncated poisson distribution. we try to find the model with the lowest aic by employing a forward selection procedure. the probability to find the correct model is investigated in a simulation study. moreover, we heuristically derive the corresponding asymptotic probabilities. an empirical study is also included. | arxiv:1903.04919 |
we introduce the notion of a totally ( $ k $ - ) bounded element of a w * - probability space $ ( m, \ varphi ) $ and, borrowing ideas of kadison, give an intrinsic characterization of the $ ^ * $ - subalgebra $ m _ { tb } $ of totally bounded elements. namely, we show that $ m _ { tb } $ is the unique strongly dense $ ^ * $ - subalgebra $ m _ 0 $ of totally bounded elements of $ m $ for which the collection of totally $ 1 $ - bounded elements of $ m _ 0 $ is complete with respect to the $ \ | \ cdot \ | _ \ varphi ^ \ # $ - norm and for which $ m _ 0 $ is closed under all operators $ h _ a ( \ log ( \ delta ) ) $ for $ a \ in \ mathbb { n } $, where $ \ delta $ is the modular operator and $ h _ a ( t ) : = 1 / \ cosh ( t - a ) $ ( see theorem 4. 3 ). as an application, we combine this characterization with rieffel and van daele ' s bounded approach to modular theory to arrive at a new language and axiomatization of w * - probability spaces as metric structures. previous work of dabrowski had axiomatized w * - probability spaces using a smeared version of multiplication, but the subalgebra $ m _ { tb } $ allows us to give an axiomatization in terms of the original algebra operations. finally, we prove the ( non - ) axiomatizability of several classes of w * - probability spaces. | arxiv:2501.14153 |
we discuss how internal rotation with fixed angular frequency can affect the solitons in the baby skyrme model in which the global o ( 3 ) symmetry is broken to the so ( 2 ). two particular choices of the potential term are considered, the " old " potential and the " new " double vacuum potential, we do not impose any assumptions about the symmetry on the fields. our results confirm existence of two types of instabilities determined by the relation between the mass parameter of the potential and the angular frequency. | arxiv:1309.4318 |
with the extraordinary maturity of data exchange in network environments and increasing the attackers capabilities, information security has become the most important process for data storage and communication. in order to provide such information security the confidentiality, data integrity, and data origin authentication must be verified based on cryptographic encryption algorithms. this paper presents a development of the advanced encryption standard ( aes ) algorithm, which is considered as the most eminent symmetric encryption algorithm. the development focuses on the generation of the integration between the developed aes based s - boxes, and the specific selected secret key generated from the quantum key distribution. | arxiv:1504.03406 |
we observe and comprehend the dynamical coulomb blockade suppression of the electrical conductance across an electronic quantum channel submitted to a temperature difference. a broadly tunable, spin - polarized ga ( al ) as quantum channel is connected on - chip, through a micron - scale metallic node, to a linear $ rc $ circuit. the latter is made up of the node ' s geometrical capacitance $ c $ in parallel with an adjustable resistance $ r \ in \ { 1 / 2, 1 / 3, 1 / 4 \ } \ times h / e ^ 2 $ formed by 2 - - 4 quantum hall channels. the system is characterized by three temperatures : a temperature of the electrons in the large electrodes ( $ t $ ) and in the node ( $ t _ \ mathrm { node } $ ), and a temperature of the electromagnetic modes of the $ rc $ circuit ( $ t _ \ mathrm { env } $ ). the temperature in the node is selectively increased by local joule dissipation, and characterized from current fluctuations. for a quantum channel in the tunnel regime, a close match is found between conductance measurements and tunnel dynamical coulomb blockade theory. in the opposite near ballistic regime, we develop a theory that accounts for different electronic and electromagnetic bath temperatures, again in very good agreement with experimental data. beyond these regimes, for an arbitrary quantum channel set in the far out - of - equilibrium situation where the temperature in the node significantly exceeds the one in the large electrodes, the equilibrium ( uniform temperature ) prediction for the conductance is recovered, albeit at a rescaled temperature $ \ alpha t _ \ mathrm { node } $. | arxiv:2104.03812 |
in this paper, a method for the digital simulation of wind velocity fields by fractional spectral moment function is proposed. it is shown that by constructing a digital filter whose coefficients are the fractional spectral moments, it is possible to simulate samples of the target process as superposition of riesz fractional derivatives of a gaussian white noise processes. the key of this simulation technique is the generalized taylor expansion proposed by the authors. the method is extended to multivariate processes and practical issues on the implementation of the method are reported. | arxiv:1212.3845 |
historically, spectroscopic techniques have been essential for studying the optical properties of thin solid films. however, existing formulae for both normal transmission and reflection spectroscopy often rely on simplified theoretical assumptions, which may not accurately align with real - world conditions. for instance, it is common to assume ( 1 ) that the thin solid layers are deposited on completely transparent thick substrates and ( 2 ) that the film surface forms a specular plane with a relatively small wedge angle. while recent studies have addressed these assumptions separately, this work presents an integrated framework that eliminates both assumptions simultaneously. in addition, the current work presents a deep review of various formulae from the literature, each with their corresponding levels of complexity. our review analysis highlights a critical trade - off between computational complexity and expression accuracy, where the newly developed formulae offer enhanced accuracy at the expense of increased computational time. our user - friendly code, which includes several classical transmittance and reflectance formulae from the literature and our newly proposed expressions, is publicly available in both python and matlab at this link. | arxiv:2409.02323 |
any n = 2 superconformal field theory ( scft ) in four dimensions has a sector of operators related to a two - dimensional chiral algebra containing a virasoro sub - algebra. moreover, there are well - known examples of isolated scfts whose chiral algebra is a virasoro algebra. in this note, we consider the chiral algebras associated with interacting n = 2 scfts possessing an exactly marginal deformation that can be interpreted as a gauge coupling ( i. e., at special points on the resulting conformal manifolds, free gauge fields appear that decouple from isolated scft building blocks ). at any point on these conformal manifolds, we argue that the associated chiral algebras possess at least three generators. in addition, we show that there are examples of scfts realizing such a minimal chiral algebra : they are certain points on the conformal manifold obtained by considering the low - energy limit of type iib string theory on the three complex - dimensional hypersurface singularity x _ 1 ^ 3 + x _ 2 ^ 3 + x _ 3 ^ 3 + a x _ 1x _ 2x _ 3 + w ^ 2 = 0. the associated chiral algebra is the a ( 6 ) theory of feigin, feigin, and tipunin. as byproducts of our work, we argue that ( i ) a collection of isolated theories can be conformally gauged only if there is a susy moduli space associated with the corresponding symmetry current moment maps in each sector, and ( ii ) n = 2 scfts with a > = c have hidden fermionic symmetries ( in the sense of fermionic chiral algebra generators ). | arxiv:1603.00887 |
query performance prediction ( qpp ) is a core task in information retrieval. the qpp task is to predict the retrieval quality of a search system for a query without relevance judgments. research has shown the effectiveness and usefulness of qpp for ad - hoc search. recent years have witnessed considerable progress in conversational search ( cs ). effective qpp could help a cs system to decide an appropriate action to be taken at the next turn. despite its potential, qpp for cs has been little studied. we address this research gap by reproducing and studying the effectiveness of existing qpp methods in the context of cs. while the task of passage retrieval remains the same in the two settings, a user query in cs depends on the conversational history, introducing novel qpp challenges. in particular, we seek to explore to what extent findings from qpp methods for ad - hoc search generalize to three cs settings : ( i ) estimating the retrieval quality of different query rewriting - based retrieval methods, ( ii ) estimating the retrieval quality of a conversational dense retrieval method, and ( iii ) estimating the retrieval quality for top ranks vs. deeper - ranked lists. our findings can be summarized as follows : ( i ) supervised qpp methods distinctly outperform unsupervised counterparts only when a large - scale training set is available ; ( ii ) point - wise supervised qpp methods outperform their list - wise counterparts in most cases ; and ( iii ) retrieval score - based unsupervised qpp methods show high effectiveness in assessing the conversational dense retrieval method, convdr. | arxiv:2305.10923 |
model extraction attacks are a kind of attacks where an adversary obtains a machine learning model whose performance is comparable with one of the victim model through queries and their results. this paper presents a novel model extraction attack, named tempest, applicable on tabular data under a practical data - free setting. whereas model extraction is more challenging on tabular data due to normalization, tempest no longer needs initial samples that previous attacks require ; instead, it makes use of publicly available statistics to generate query samples. experiments show that our attack can achieve the same level of performance as the previous attacks. moreover, we identify that the use of mean and variance as statistics for query generation and the use of the same normalization process as the victim model can improve the performance of our attack. we also discuss a possibility whereby tempest is executed in the real world through an experiment with a medical diagnosis dataset. we plan to release the source code for reproducibility and a reference to subsequent works. | arxiv:2109.14857 |
this paper presents the measured sensitivity of csiro ' s first mk. ii phased array feed ( paf ) on an askap antenna. the mk. ii achieves a minimum system - temperature - over - efficiency $ t _ \ mathrm { sys } / \ eta $ of 78 k at 1. 23 ghz and is 95 k or better from 835 mhz to 1. 8 ghz. this paf was designed for the australian ska pathfinder telescope to demonstrate fast astronomical surveys with a wide field of view for the square kilometre array ( ska ). | arxiv:1509.00544 |
hierarchies are of fundamental interest in both stochastic optimal control and biological control due to their facilitation of a range of desirable computational traits in a control algorithm and the possibility that they may form a core principle of sensorimotor and cognitive control systems. however, a theoretically justified construction of state - space hierarchies over all spatial resolutions and their evolution through a policy inference process remains elusive. here, a formalism for deriving such normative representations of discrete markov decision processes is introduced in the context of graphs. the resulting hierarchies correspond to a hierarchical policy inference algorithm approximating a discrete gradient flow between state - space trajectory densities generated by the prior and optimal policies. | arxiv:1801.00048 |
the growing popularity of virtual and augmented reality communications and 360 { \ deg } video streaming is moving video communication systems into much more dynamic and resource - limited operating settings. the enormous data volume of 360 { \ deg } videos requires an efficient use of network bandwidth to maintain the desired quality of experience for the end user. to this end, we propose a framework for viewport - driven rate - distortion optimized 360 { \ deg } video streaming that integrates the user view navigation pattern and the spatiotemporal rate - distortion characteristics of the 360 { \ deg } video content to maximize the delivered user quality of experience for the given network / system resources. the framework comprises a methodology for constructing dynamic heat maps that capture the likelihood of navigating different spatial segments of a 360 { \ deg } video over time by the user, an analysis and characterization of its spatiotemporal rate - distortion characteristics that leverage preprocessed spatial tilling of the 360 { \ deg } view sphere, and an optimization problem formulation that characterizes the delivered user quality of experience given the user navigation patterns, 360 { \ deg } video encoding decisions, and the available system / network resources. our experimental results demonstrate the advantages of our framework over the conventional approach of streaming a monolithic uniformly encoded 360 { \ deg } video and a state - of - the - art reference method. considerable video quality gains of 4 - 5 db are demonstrated in the case of two popular 4k 360 { \ deg } videos. | arxiv:1803.08177 |
counterfactual prediction is about predicting outcome of the unobserved situation from the data. for example, given patient is on drug a, what would be the outcome if she switch to drug b. most of existing works focus on modeling counterfactual outcome based on static data. however, many applications have time - varying confounding effects such as multiple treatments over time. how to model such time - varying effects from longitudinal observational data? how to model complex high - dimensional dependency in the data? to address these challenges, we propose deep recurrent inverse treatment weighting ( deeprite ) by incorporating recurrent neural networks into two - phase adjustments for the existence of time - varying confounding in modern longitudinal data. in phase i cohort reweighting we fit one network for emitting time dependent inverse probabilities of treatment, use them to generate a pseudo balanced cohort. in phase ii outcome progression, we input the adjusted data to the subsequent predictive network for making counterfactual predictions. we evaluate deeprite on both synthetic data and a real data collected from sepsis patients in the intensive care units. deeprite is shown to recover the ground truth from synthetic data, and estimate unbiased treatment effects from real data that can be better aligned with the standard guidelines for management of sepsis thanks to its applicability to create balanced cohorts. | arxiv:2010.15028 |
in this paper, we propose a novel cross - attention - based generative adversarial network ( gan ) for the challenging person image generation task. cross - attention is a novel and intuitive multi - modal fusion method in which an attention / correlation matrix is calculated between two feature maps of different modalities. specifically, we propose the novel xinggan ( or crossinggan ), which consists of two generation branches that capture the person ' s appearance and shape, respectively. moreover, we propose two novel cross - attention blocks to effectively transfer and update the person ' s shape and appearance embeddings for mutual improvement. this has not been considered by any other existing gan - based image generation work. to further learn the long - range correlations between different person poses at different scales and sub - regions, we propose two novel multi - scale cross - attention blocks. to tackle the issue of independent correlation computations within the cross - attention mechanism leading to noisy and ambiguous attention weights, which hinder performance improvements, we propose a module called enhanced attention ( ea ). lastly, we introduce a novel densely connected co - attention module to fuse appearance and shape features at different stages effectively. extensive experiments on two public datasets demonstrate that the proposed method outperforms current gan - based methods and performs on par with diffusion - based methods. however, our method is significantly faster than diffusion - based methods in both training and inference. | arxiv:2501.08900 |
high - dimensional biphoton states are promising resources for quantum applications, ranging from high - dimensional quantum communications to quantum imaging. a pivotal task is fully characterising these states, which is generally time - consuming and not scalable when projective measurement approaches are adopted. however, new advances in coincidence imaging technologies allow for overcoming these limitations by parallelising multiple measurements. here, we introduce biphoton digital holography, in analogy to off - axis digital holography, where coincidence imaging of the superposition of an unknown state with a reference one is used to perform quantum state tomography. we apply this approach to single photons emitted by spontaneous parametric down - conversion in a nonlinear crystal when the pump photons possess various quantum states. the proposed reconstruction technique allows for a more efficient ( 3 order - of - magnitude faster ) and reliable ( an average fidelity of 87 % ) characterisation of states in arbitrary spatial modes bases, compared with previously performed experiments. multi - photon digital holography may pave the route toward efficient and accurate computational ghost imaging and high - dimensional quantum information processing. | arxiv:2301.13046 |
edge states of semi - infinite nanowires in tight binding limit are examined. we argue that understanding these edge states provides a pathway to generic comprehension of surface states in many semi - infinite physical systems. it is shown that the edge states occur within the gaps of the corresponding bulk spectrum ( thus also called the midgap states ). more importantly, we show that the presence of these midgap states reflects an underlying generalized supersymmetry. this supersymmetric structure is a generalized rotational symmetry among sublattices and results in a universal tendency : all midgap states tend to vanish with periods commensurate with the underlying lattice. based on our formulation, we propose a structure with superlattice in hopping to control the number of localized electronic states occurring at the ends of the nanowires. other implications are also discussed. in particular, it is shown that the ordinarily recognized impurity states can be viewed as disguised midgap states. | arxiv:cond-mat/0411430 |
accreting neutron stars ( nss ) are expected to emit a redshifted 2. 2 mev line due to the capture of neutrons produced through the spallation processes of $ ^ 4 $ he and heavier ions in their atmospheres. detecting this emission would offer an independent method for constraining the equation of state of nss and provide valuable insights into nuclear reactions occurring in extreme gravitational and magnetic environments. typically, a higher mass accretion rate is expected to result in a higher 2. 2 mev line intensity. however, when the mass accretion rate approaches the critical threshold, the accretion flow is decelerated by the radiative force, leading to a less efficient production of free neutrons and a corresponding drop in the flux of the spectral line. this makes the brightest x - ray pulsars unsuitable candidates for gamma - ray line detection. in this work, we present a theoretical framework for predicting the optimal x - ray luminosity required to detect a redshifted 2. 2 mev line in a strongly magnetized ns. as the integral mission nears its conclusion, we have undertaken a thorough investigation of the spi data of this line in a representative sample of accreting nss. no redshifted 2. 2 mev line was detected. for each spectrum, we have determined the 3 - sigma upper limits of the line intensity, assuming different values of the line width. our findings suggest that advancing our understanding of the emission mechanism of the 2. 2 mev line, as well as the accretion flow responsible for it, will require a substantial increase in sensitivity from future mev missions. for example, for a bright x - ray binary such as sco x - 1, we would need at least a 3 - sigma line point source sensitivity of ~ 1e - 6 ph / cm ^ 2 / s, that is, about two orders of magnitude better than that currently achieved. [ abridged ] | arxiv:2409.05535 |
we use the method of darboux coverings to discuss the invariant submanifolds of the kp equations, presented as conservation laws in the space of monic laurent series in the spectral parameter ( the space of the hamiltonian densities ). we identify a special class of these submanifolds with the rational invariant submanifolds entering matrix models of $ 2d $ - - gravity, recently characterized by dickey and krichever. four examples of the general procedure are provided. | arxiv:solv-int/9610002 |
the formation of cosmic structures is an important diagnostic for both the dynamics of the cosmological model and the underlying theory of gravity. at the linear level of these structures, certain degeneracies remain between different cosmological models and alternative gravity theories. it is thus indispensable to study the non - linear, late - time evolution of cosmic structures to try and disentangle their fundamental properties caused by the cosmological model or gravity theory itself. conventionally, non - linear cosmic structure formation is studied by means of computationally expensive numerical simulations. since these inevitably suffer from shot noise and are too time consuming to systematically scrutinize large parameter spaces of cosmological models or fundamental theories, analytical methods are needed to overcome the limitations of numerical simulations. recently, a new analytic approach to non - linear cosmic structure formation has been proposed based on kinetic field theory for classical particle ensembles. within this theory, a closed, analytic, non - perturbative and parameter - free equation could be derived for the non - linear power spectrum of cosmic density perturbations which agrees very well with numerically simulated results to wave numbers $ k \ lesssim10 \, h \, \ mathrm { mpc } ^ { - 1 } $ at redshift $ z = 0 $. in this letter, we study for the first time the implications of alternative gravity theories for non - linear cosmic structure formation applying this promising new analytic framework. as an illustrative example, we consider vector - tensor theories, which support very interesting isotropic cosmological solutions. | arxiv:1901.01041 |
we study singular radially symmetric solution to the lin - ni - takagi equation for a supercritical power non - linearity in dimension $ n \ geq 3 $. it is shown that for any ball and any $ k \ geq 0 $, there is a singular solution that satisfies neumann boundary condition and oscillates at least $ k $ times around the constant equilibrium. moreover, we show that the morse index of the singular solution is finite or infinite if the exponent is respectively larger or smaller than the joseph - - lundgren exponent. | arxiv:2002.07887 |
in this paper, we generalize the results of ( $ \ textit { groups, geom. dyn. } $, forthcoming ) to describe the split left - invariant riemannian distances on higher - rank sol - type groups $ g = \ mathbf { n } \ rtimes \ mathbb { r } ^ k $. we show that the rough isometry type of such a distance is determined by a specific restriction of the metric to $ \ mathbb { r } ^ k $, and therefore the space of rough similarity types of distances is parameterized by the symmetric space $ sl _ k ( \ mathbb { r } ) / so _ k ( \ mathbb { r } ) $. in order to prove this result, we describe a family of uniformly roughly geodesic paths, which arise by way of the new technique of $ \ textit { euclidean curve surgery } $. | arxiv:2412.11290 |
language technology, often called human language technology ( hlt ), studies methods of how computer programs or electronic devices can analyze, produce, modify or respond to human texts and speech. working with language technology often requires broad knowledge not only about linguistics but also about computer science. it consists of natural language processing ( nlp ) and computational linguistics ( cl ) on the one hand, many application oriented aspects of these, and more low - level aspects such as encoding and speech technology on the other hand. note that these elementary aspects are normally not considered to be within the scope of related terms such as natural language processing and ( applied ) computational linguistics, which are otherwise near - synonyms. as an example, for many of the world ' s lesser known languages, the foundation of language technology is providing communities with fonts and keyboard setups so their languages can be written on computers or mobile devices. = = references = = = = external links = = johns hopkins university human language technology center of excellence carnegie mellon university language technologies institute institute for applied linguistics ( iula ) at universitat pompeu fabra. barcelona, spain german research centre for artificial intelligence ( dfki ) language technology lab clt : centre for language technology in gothenburg, sweden the center for speech and language technologies ( csalt ) at the lahore university [ sic ] of management sciences ( lums ) globalization and localization association ( gala ) scriptsource, a reference to the writing systems of the world and the remaining needs for supporting them in the computing realm. high performance language technologies ( hplt ) development funded by the european commission. [ 1 ] | https://en.wikipedia.org/wiki/Language_technology |
we prove p. alexandersson ' s conjecture that for every complex polynomial $ p $ of degree $ d \ geq 2 $ the convex hull $ h _ p $ of the julia set $ j _ p $ of $ p $ satisfies $ p ^ { - 1 } ( h _ p ) \ subset h _ p $. we further prove that the equality $ p ^ { - 1 } ( h _ p ) = h _ p $ is achieved only if $ p $ is affinely conjugated to the chebyshev polynomial $ t _ d $ of degree $ d $, to $ - t _ d $ or a monomial $ c z ^ d $ with $ | c | = 1 $. | arxiv:2004.12521 |
recently, several exotic bosons have been confirmed as multi - quark states, but there are violent disputes about their inner structures, namely if they are molecular states or tetraquarks, or even mixtures of the two structures. it would be interesting to experimentally search for non - strange four - quark states with open charm or bottom which are lighter than $ \ lambda _ c $ or $ \ lambda _ b $. reasonable arguments indicate that they are good candidates of pure molecular states $ d \ pi $ or $ b \ pi $ because pions are the lightest boson. both $ b \ pi $ and $ d \ pi $ bound states do not decay via strong interaction. the $ b \ pi $ molecule may decay into $ b ^ * $ by radiating a photon, whereas $ d \ pi $ molecule can only decay via weak interaction. in this paper we explore the mass spectra of $ b \ pi $ molecular statesby solving the corresponding b - s equation. then the rate of radiative decay $ | \ frac { 3 } { 2 }, \ frac { 1 } { 2 } \ rangle \ to b ^ * \ gamma $ is calculated and our numerical results indicate that the processes can be measured by the future experiment. we also briefly discuss the $ d \ pi $ case, due to the constraint of the final state phase space, it can only decay via weak interaction. | arxiv:1612.08390 |
chemical kinetic mechanisms can be represented by sets of elementary reactions that are easily translated into mathematical terms using physicochemical relationships. the schematic representation of reactions captures the interactions between reacting species and products. determining the minimal chemical interactions underlying the dynamic behavior of systems is a major task. in this paper, we introduce a novel approach for the identification of the influential reactions in chemical reaction networks for combustion applications, using a data - driven sparse - learning technique. the proposed approach identifies a set of influential reactions using species concentrations and reaction rates, with minimal computational cost without requiring additional data or simulations. the new approach is applied to analyze the combustion chemistry of h2 and c3h8 in a constant - volume homogeneous reactor. the influential reactions identified by the sparse - learning method are consistent with the current kinetics knowledge of chemical mechanisms. additionally, we show that a reduced version of the parent mechanism can be generated as a combination of the influential reactions identified at different times and conditions and that for both h2 and c3h8 this reduced mechanism performs closely to the parent mechanism as a function of ignition delay over a wide range of conditions. our results demonstrate the potential of the sparse - learning approach as an effective and efficient tool for mechanism analysis and mechanism reduction. | arxiv:1712.06281 |
the southern wide - field gamma - ray observatory ( swgo ) collaboration is currently engaged in design and prototyping work towards the realisation of this future gamma - ray facility. swgo will complement cta and the existing ground - particle based - detectors of the northern hemisphere ( hawc and lhaaso ) with a very wide field and high duty cycle view of the southern sky. here i summarise the status of the project and plans for the future, including expectations for sensitivity and science targets as well as the status of the site search and technological developments. | arxiv:2111.13158 |
parabolic equations on evolving domains model a multitude of applications including various industrial processes such as the molding of heated materials. such equations are numerically challenging as they require large - scale computations and the usage of parallel hardware. domain decomposition is a common choice of numerical method for stationary domains, as it gives rise to parallel discretizations. in this study, we introduce a variational framework that extends the use of such methods to evolving domains. in particular, we prove that transmission problems on evolving domains are well posed and equivalent to the corresponding parabolic problems. this in turn implies that the standard non - overlapping domain decompositions, including the robin - robin method, become well defined approximations. furthermore, we prove the convergence of the robin - - robin method. the framework is based on a generalization of fractional sobolev - bochner spaces on evolving domains, time - dependent steklov - poincar \ ' e operators, and elements of the approximation theory for monotone maps. | arxiv:2503.05267 |
bessel - type convolution algebras of bounded borel measures on the matrix cones of positive semidefinite $ q \ times q $ - matrices over $ \ mathbb r, \ mathbb c, \ mathbb h $ were introduced recently by r \ " osler. these convolutions depend on some continuous parameter, generate commutative hypergroup structures and have bessel functions of matrix argument as characters. here, we first study the rich algebraic structure of these hypergroups. in particular, the subhypergroups and automorphisms are classified, and we show that each quotient by a subhypergroup carries a hypergroup structure of the same type. the algebraic properties are partially related to properties of random walks on matrix bessel hypergroups. in particular, known properties of wishart distributions, which form gaussian convolution semigroups on these hypergroups, are put into a new light. moreover, limit theorems for random walks on these hypergroups are presented. in particular, we obtain strong laws of large numbers and a central limit theorem with wishart distributions as limits. | arxiv:math/0603017 |
a mathematical model of the natural origin of our universe is presented. the model is based only on well - established physics. no claim is made that this model uniquely represents exactly how the universe came about. but the viability of a single model serves to refute any assertions that the universe cannot have come about by natural means. | arxiv:0710.3137 |
we consider decay of metastable states of forced vibrations of a quantum oscillator close to bifurcation points, where dissipation becomes effectively strong. we show that decay occurs via quantum activation over an effective barrier. the decay probability $ w $ scales with the distance $ \ eta $ to the bifurcation point as $ | \ ln w | \ propto \ eta ^ { \ xi } $. the exponent $ \ xi $ is found for a resonantly driven oscillator and an oscillator modulated at nearly twice its eigenfrequency. | arxiv:cond-mat/0606198 |
given $ n $ pairwise disjoint sets $ x _ 1, \ ldots, x _ n $, we call the elements of $ s = x _ 1 \ times \ ldots \ times x _ n $ strings. a nonempty set of strings $ w \ subseteq s $ is said to be well - connected if for every $ v \ in w $ and for every $ i \, ( 1 \ le i \ le n ) $, there is another element $ v ' \ in w $ which differs from $ v $ only in its $ i $ th coordinate. we prove a conjecture of yaokun wu and yanzhen xiong by showing that every set of more than $ \ prod _ { i = 1 } ^ n | x _ i | - \ prod _ { i = 1 } ^ n ( | x _ i | - 1 ) $ strings has a well - connected subset. this bound is tight. | arxiv:2102.10704 |
we consider a keller - segel model with non - linear porous medium type diffusion and nonlocal attractive power law interaction, focusing on potentials that are less singular than newtonian interaction. here, the nonlinear diffusion is chosen to be $ \ frac { 2d } { d + 2s } < m < 2 - \ frac { 2s } { d } $ in which case the steady states are compactly supported. we analyse under which conditions on the initial data the regime that attractive forces are stronger than diffusion occurs and classify the global existence and finite time blow - up of solutions. it is shown that there is a threshold value which is characterized by the optimal constant of a variant of hardy - littlewood - sobolev inequality such that the solution will exist globally if the initial data is below the threshold, while the solution blows up in finite time when the initial data is above the threshold. | arxiv:2306.16870 |
image captioning is shown to be able to achieve a better performance by using scene graphs to represent the relations of objects in the image. the current captioning encoders generally use a graph convolutional net ( gcn ) to represent the relation information and merge it with the object region features via concatenation or convolution to get the final input for sentence decoding. however, the gcn - based encoders in the existing methods are less effective for captioning due to two reasons. first, using the image captioning as the objective ( i. e., maximum likelihood estimation ) rather than a relation - centric loss cannot fully explore the potential of the encoder. second, using a pre - trained model instead of the encoder itself to extract the relationships is not flexible and cannot contribute to the explainability of the model. to improve the quality of image captioning, we propose a novel architecture reformer - - a relational transformer to generate features with relation information embedded and to explicitly express the pair - wise relationships between objects in the image. reformer incorporates the objective of scene graph generation with that of image captioning using one modified transformer model. this design allows reformer to generate not only better image captions with the bene - fit of extracting strong relational image features, but also scene graphs to explicitly describe the pair - wise relation - ships. experiments on publicly available datasets show that our model significantly outperforms state - of - the - art methods on image captioning and scene graph generation | arxiv:2107.14178 |
the electron - photon interaction in 2d materials obeys the rule of electron valley - photon polarization correspondence. at the quantum level, such correspondence can be utilized to entangle valleys and polarizations and attain the transfer of quantum states ( or information ) between valley and photon qubits. our work presents a theoretical study of the interaction between the two types of qubits and the resultant quantum state transfer. a generic setup is introduced, which involves optical cavities enhancing the electron - photon interaction as well as facilitating both the entanglement and un - entanglement between valleys and polarizations required by the transfer. the quantum system considered consists of electrons, optically excited trions, and cavity photons, with photons moving in and out of the system. a wave equation based analysis is performed, and analytical expressions are derived for the two important figures of merits that characterize the transfer, namely, yield and fidelity, allowing for the investigation of their dependences on various qubit and cavity parameters. a numerical study of the yield and fidelity has also been carried out. overall, this work shows promising characteristics in the valley - photon state transfer, with the conclusion that the valley - polarization correspondence can be exploited to achieve the transfer with good yield and high fidelity. | arxiv:1701.06131 |
objective : endobronchial valves are a minimally invasive treatment for emphysema. after bronchoscopic placement the valves reduce the flow of air into targeted areas of the lung, causing collapse, and allowing the remainder of the lung to function more effectively. approach : x - ray velocimetry is a novel method that uses x - ray images taken during a breath to track lung motion, producing 3d maps of local ventilation. healthy sheep received a ct scan and underwent x - ray velocimetry imaging before and after endobronchial valves were placed in the lung. sheep were imaged again when the endobronchial valves were removed after 14 days. main results : x - ray velocimetry enabled visualisation and quantification of a reduction of airflow to the areas downstream of the endobronchial valves, both in areas where collapse was and was not visible in ct. changes to ventilation were also clearly visible in the remainder of the lungs. significance : this preclinical study has shown x - ray velocimetry is capable of detecting changes to ventilation caused by endobronchial valve placement, paving the way towards use in patients. | arxiv:2502.19780 |
we present a heuristic strategy for marginal map ( mmap ) queries in graphical models. the algorithm is based on a reduction of the task to a polynomial number of marginal inference computations. given an input evidence, the marginals mass functions of the variables to be explained are computed. marginal information gain is used to decide the variables to be explained first, and their most probable marginal states are consequently moved to the evidence. the sequential iteration of this procedure leads to a mmap explanation and the minimum information gain obtained during the process can be regarded as a confidence measure for the explanation. preliminary experiments show that the proposed confidence measure is properly detecting instances for which the algorithm is accurate and, for sufficiently high confidence levels, the algorithm gives the exact solution or an approximation whose hamming distance from the exact one is small. | arxiv:2002.04827 |
we define generalized hamming weights for almost affine codes. we show how various aspects and applications of generalized hamming weights for linear codes, such as wei duality, generalized kung ' s bound, profiles, connection to wire - tap channels of type ii, apply to the larger class of almost affine codes in general. in addition we discuss duality of almost affine codes, and of the smaller class of multilinear codes. we also give results about weight distributions of infinite series of almost affine codes, each series obtained from a fixed code by extending the code alphabet. | arxiv:1601.01504 |
the generalized stacking fault ( gsf ) energy surfaces have received considerable attention due to their close relation to the mechanical properties of solids. we present a detailed study of the gsf energy surfaces of silicon within the framework of density functional theory. we have calculated the gsf energy surfaces for the shuffle and glide set of the ( 111 ) plane, and that of the ( 100 ) plane of silicon, paying particular attention to the effects of the relaxation of atomic coordinates. based on the calculated gsf energy surfaces and the peierls - nabarro model, we obtain estimates for the dislocation profiles, core energies, peierls energies, and the corresponding stresses for various planar dislocations of silicon. | arxiv:mtrl-th/9604006 |
prior work has shown that analyzing the use of first - person singular pronouns can provide insight into individuals ' mental status, especially depression symptom severity. these findings were generated by counting frequencies of first - person singular pronouns in text data. however, counting doesn ' t capture how these pronouns are used. recent advances in neural language modeling have leveraged methods generating contextual embeddings. in this study, we sought to utilize the embeddings of first - person pronouns obtained from contextualized language representation models to capture ways these pronouns are used, to analyze mental status. de - identified text messages sent during online psychotherapy with weekly assessment of depression severity were used for evaluation. results indicate the advantage of contextualized first - person pronoun embeddings over standard classification token embeddings and frequency - based pronoun analysis results in predicting depression symptom severity. this suggests contextual representations of first - person pronouns can enhance the predictive utility of language used by people with depression symptoms. | arxiv:2310.03232 |
this contribution to the published proceedings records the opening talk i presented on the first morning of the 2005 international linear collider workshop in snowmass, co, august 14 - 27, 2005. it includes a summary of the motivation for the workshop, the scientific goals and charges for the working groups, the initial plans of the accelerator, detector, and physics groups, and the activities of the communication, education, and outreach group. this document also describes organizational aspects of the meeting, particularly the scientific committee structure, the self - organization of the working groups, the composition of the indispensable secretariat and computer support teams, and the sources of funding support. the report serves as an introduction to the proceedings whose individual papers and summary documents must be consulted for an appreciation of the accomplishments and progress made at snowmass in 2005 toward the realization of an international linear collider. | arxiv:hep-ph/0602117 |
insights from stripe incommensurabilities and antiferromagnetic stability indicate that the magnetic moments of both host cu ^ 2 + ions and cu atoms from electron doping support the thermal hall effect in cuprates, whereas those of o atoms from hole doping oppose it. | arxiv:2201.13203 |
we propose a model for co - evolving ecosystems that takes into account two levels of description of an organism, for instance genotype and phenotype. performance at the macroscopic level forces mutations at the microscopic level. these, in turn, affect the dynamics of the macroscopic variables. in some regions of parameter space, the system self - organises into a state with localised activity and power law distributions. | arxiv:adap-org/9905001 |
a redundant generating function is a generating function having terms which are not part of the solution of the original problem. we use redundant generating functions to study two path problems. in the first application we explain a surprising occurrence of catalan numbers in counting paths that stay below the line y = 2x. in the second application we prove a conjecture of niederhausen and sullivan. | arxiv:1107.3870 |
we quantitatively study the percentage of fake events present in ccqe and ccres interactions and the impact of final state interactions on the neutrino oscillation parameters at dune. resonance interaction will be the most dominant interaction in the oscillation sensitive region of dune. the effect of final - state interactions for dune oscillation physics is analysed in an ideal and realistic detector scenario. the $ \ nu _ { \ mu } $ - disappearance oscillation channel is studied using lar detector. we find that nuclear effects and detector thresholds plays an significant role in ccqe and ccres interactions and these nuclear effects induces a significant bias in the determination of atmospheric oscillation parameters. the impression of nuclear effects on the determination of $ \ theta _ { 23 } $ is quantified in this work. | arxiv:1804.02191 |
this chapter presents the bilevel optimization library of the test problems ( bolib for short ), which contains a collection of test problems, with continuous variables, to help support the development of numerical solvers for bilevel optimization. the library contains 173 examples with 138 nonlinear, 24 linear, and 11 simple bilevel optimization problems. this bolib collection is probably the largest bilevel optimization library of test problems. moreover, as the library is computationenabled with the matlab m - files of all the examples, it provides a uniform basis for testing and comparing algorithms. the library, together with all the related codes, is freely available at biopt. github. io / bolib. | arxiv:1812.00230 |
predictions of the existence of well - defined deeply bound pionic atom states for heavy nuclei and the eventual observation of such states by the ( d, 3he ) reaction have revived interest in the pion - nucleus interaction at threshold and in its relation to the corresponding pion - nucleon interaction. explanation of the ' anomalous ' s - wave repulsion in terms of partial restoration of chiral symmetry and / or in terms of energy - dependence effects have been tested in global fits to pionic atom data and in a recent dedicated elastic scattering experiment. the role of neutron density distributions in this context is discussed in detail for the first time. | arxiv:nucl-th/0607049 |
in this paper, we make the first attempt to apply the boundary integrated neural networks ( binns ) for the numerical solution of two - dimensional ( 2d ) elastostatic and piezoelectric problems. binns combine artificial neural networks with the well - established boundary integral equations ( bies ) to effectively solve partial differential equations ( pdes ). the bies are utilized to map all the unknowns onto the boundary, after which these unknowns are approximated using artificial neural networks and resolved via a training process. in contrast to traditional neural network - based methods, the current binns offer several distinct advantages. first, by embedding bies into the learning procedure, binns only need to discretize the boundary of the solution domain, which can lead to a faster and more stable learning process ( only the boundary conditions need to be fitted during the training ). second, the differential operator with respect to the pdes is substituted by an integral operator, which effectively eliminates the need for additional differentiation of the neural networks ( high - order derivatives of neural networks may lead to instability in learning ). third, the loss function of the binns only contains the residuals of the bies, as all the boundary conditions have been inherently incorporated within the formulation. therefore, there is no necessity for employing any weighing functions, which are commonly used in traditional methods to balance the gradients among different objective functions. moreover, binns possess the ability to tackle pdes in unbounded domains since the integral representation remains valid for both bounded and unbounded domains. extensive numerical experiments show that binns are much easier to train and usually give more accurate learning solutions as compared to traditional neural network - based methods. | arxiv:2308.01053 |
we revisit completion modulo equational theories for left - linear term rewrite systems where unification modulo the theory is avoided and the normal rewrite relation can be used in order to decide validity questions. to that end, we give a new correctness proof for finite runs and establish a simulation result between the two inference systems known from the literature. given a concrete reduction order, novel canonicity results show that the resulting complete systems are unique up to the representation of their rules ' right - hand sides. furthermore, we show how left - linear ac completion can be simulated by general ac completion. in particular, this result allows us to switch from the former to the latter at any point during a completion process. | arxiv:2405.17109 |
we demonstrate that widom ' s particle insertion technique provides a convenient and efficient method to determine the effective pair interaction between complex, composite soft - matter particles in the zero - density limit. by means of three different test systems, i. e. amphiphilic dendrimers, electrostatic polymers and colloids coated with electrostatic polymers, we demonstrate the validity and the power of the presented method. | arxiv:1010.1422 |
we calculate the radial surface brightness profile of the image of a gamma - ray - burst ( grb ) afterglow. the afterglow spectrum consists of several power - law segments separated by breaks. the image profile changes considerably across each of the spectral breaks. it also depends on the density profile of the ambient medium into which the grb fireball propagates. gravitational microlensing by an intervening star can resolve the afterglow image. we calculate the predicted magnification history of grb afterglows as a function of observed frequency and ambient medium properties. we find that intensive monitoring of a microlensed afterglow lightcurve can be used to reconstruct the parameters of the fireball and its environment, and provide constraints on particle acceleration and magnetic field amplification in relativistic blast waves. | arxiv:astro-ph/0101234 |
we derive the formula for the stationary states of particle - number conserving exclusion processes infinitesimally perturbed by inhomogeneous adsorption and desorption. the formula not only proves but also generalises the conjecture proposed in arxiv : 1711. 06949 to account for inhomogeneous adsorption and desorption. as an application of the formula, we draw part of the phase diagrams of the open asymmetric simple exclusion process with and without langmuir kinetics, correctly reproducing known results. | arxiv:2406.02675 |
the copper ferrite thin films have been deposited by rf sputtering at a 50w rf power. the as - deposited films are annealed in air at $ 800 ^ { \ circ } $ c and then slow cooled. the as - deposited ( ad ) as well as slow cooled ( sc ) films are studied using a squid magnetometer. the m vs h curves have been recorded at various temperatures between 5k to 300k. the coercivities obtained from the mh curves are then plotted against temperature ( t ). the magnetization in the films does not saturate, even at the highest field of 7t. the high field part of the m vs h curves is fitted using the h1 / 2 term of chikazumi expression m ( h ) = q * ( 1 - a / hn ), with n = 1 / 2. the variation of coefficient ' a ' of h1 / 2 term has been observed with temperature ( t ). an attempt has been made to correlate this with the coercivity ( hc ) in the case of annealed films. | arxiv:1010.1882 |
software dependence networks are shown to be scale - free and asymmetric. we then study how software components are affected by the failure of one of them, and the inverse problem of locating the faulty component. software at all levels is fragile with respect to the failure of a random single component. locating a faulty component is easy if the failures only affect their nearest neighbors, while it is hard if the failures propagate further. | arxiv:cond-mat/0306509 |
the effect of ultrashort laser - induced morphological changes upon irradiation of silicon with double pulse sequences is investigated under conditions that lead to mass removal. the temporal delay between twelve double and equal - energy pulses ( ep = 0. 24j / cm2 each, with pulse duration tp = 430fs, 800nm laser wavelength ) was varied between 0 and 14ps and a decrease of the damaged area, crater depth size and periodicity of the induced subwavelength ripples ( by 3 - 4 % ) was observed with increasing pulse delay. the proposed underlying mechanism is based on the combination of carrier excitation and energy thermalization and capillary wave solidification and aims to provide an alternative explanation to the control of ripple periodicity by temporal pulse tailoring. this work demonstrates the potential of pulse shaping technology to improve nano / micro processing. | arxiv:1307.8267 |
we study the quantization of a scalar field on a classical background given by the szekeres class of solutions, which represent the collision of two gravitational plane waves with constant polarization. these solutions consist of two approaching gravitational plane waves moving in a flat background and an interaction region which always contains a curvature singularity. following a suitable approximate procedure, introduced in a previous paper, we propose a way to compute the vacuum expectation value of the stress - energy tensor throughout the causal past region of the collision center in the quantum state which corresponds to the vacuum before the arrival of the waves. | arxiv:gr-qc/9802055 |
we propose in this paper a polynomial representation of tu - games, fuzzy measures, capacities, and more generally set functions. our representation needs a countably infinite set of players and the natural ordering of finite sets of $ \ mathbb { n } $, defined recursively. for a given basis of the vector space of games, we associate to each game $ v $ a formal polynomial of degree at most $ 2 ^ n - 1 $ whose coefficients are the coordinates of $ v $ in the given basis. by the fundamental theorem of algebra, $ v $ can be represented by the roots of the polynomial. we present some new families of games stemming from this polynomial context, like the irreducible games, the multiplicative games and the cyclotomic games. | arxiv:2401.12741 |
graph clustering is an unsupervised machine learning method that partitions the nodes in a graph into different groups. despite achieving significant progress in exploiting both attributed and structured data information, graph clustering methods often face practical challenges related to data isolation. moreover, the absence of collaborative methods for graph clustering limits their effectiveness. in this paper, we propose a collaborative graph clustering framework for attributed graphs, supporting attributed graph clustering over vertically partitioned data with different participants holding distinct features of the same data. our method leverages a novel technique that reduces the sample space, improving the efficiency of the attributed graph clustering method. furthermore, we compare our method to its centralized counterpart under a proximity condition, demonstrating that the successful local results of each participant contribute to the overall success of the collaboration. we fully implement our approach and evaluate its utility and efficiency by conducting experiments on four public datasets. the results demonstrate that our method achieves comparable accuracy levels to centralized attributed graph clustering methods. our collaborative graph clustering framework provides an efficient and effective solution for graph clustering challenges related to data isolation. | arxiv:2411.12329 |
we study the effects of the ionizing and dissociating photons produced by popiii objects on the surrounding intergalactic medium. we find that the typical size of a h _ 2 photodissociated region, r _ d ~ 1 - 5 kpc, is smaller than the mean distance between sources at z ~ 20 - 30, but larger than the ionized region by a factor depending on the detailed properties of the emission spectrum. this implies that clearing of intergalactic h _ 2 occurs before reionization of the universe is complete. in the same redshift range, the soft - uv background in the lyman - werner bands, when the intergalactic h and h _ 2 opacity is included, is found to be j _ lw ~ 1d - 30 - 1d - 27 erg cm ^ { - 2 } s ^ { - 1 } hz ^ { - 1 }. this value is well below the threshold required for the negative feedback of popiii objects on the subsequent galaxy formation to be effective in that redshift range. | arxiv:astro-ph/9811137 |
this paper has been withdrawn for extensive revision. | arxiv:cond-mat/9812023 |
we study the acylindrical hyperbolicity of the outer automorphism group of a right - angled artin group $ a _ \ gamma $. when the defining graph $ \ gamma $ has no sil - pair ( separating intersection of links ), we obtain a necessary and sufficient condition for $ \ mathrm { out } ( a _ \ gamma ) $ to be acylindrically hyperbolic. as a corollary, if $ \ gamma $ is a random connected graph satisfying a certain probabilistic condition, then $ \ mathrm { out } ( a _ \ gamma ) $ is not acylindrically hyperbolic with high probability. when $ \ gamma $ has a maximal sil - pair system, we derive a classification theorem for partial conjugations. such a classification theorem allows us to show that the acylindrical hyperbolicity of $ \ mathrm { out } ( a _ \ gamma ) $ is closely related to the existence of a specific type of partial conjugations. | arxiv:2405.19702 |
deeplearning has been used to solve complex problems in various domains. as it advances, it also creates applications which become a major threat to our privacy, security and even to our democracy. such an application which is being developed recently is the " deepfake ". deepfake models can create fake images and videos that humans cannot differentiate them from the genuine ones. therefore, the counter application to automatically detect and analyze the digital visual media is necessary in today world. this paper details retraining the image classification models to apprehend the features from each deepfake video frames. after feeding different sets of deepfake clips of video fringes through a pretrained layer of bottleneck in the neural network is made for every video frame, already stated layer contains condense data for all images and exposes artificial manipulations in deepfake videos. when checking deepfake videos, this technique received more than 87 per cent accuracy. this technique has been tested on the face forensics dataset and obtained good accuracy in detection. | arxiv:2004.14178 |
the self - consistent matter coupling is found in a broad class of minimally modified gravity theories which was discovered recently. all constraints in the theories remain first class and thus a graviton has only 2 local degrees of freedom. the cosmological solution of one of the examples in this class, the so - called square root gravity, exhibits a singularity freeness at high energy limit. at low energy limit, the theory smoothly connects to gr. a general feature of the theories in this class, with the self - consistent matter coupling discovered in our current work, is the non - trivial interaction among different components of matter sector. we have also checked the hamiltonian structure of a scalar qed coupling to the square root gravity in the same manner. all constraints in the theory are first class too and thus the local u ( 1 ) gauge symmetry in scalar qed is preserved. | arxiv:1811.02467 |
we explore the structural properties of anomalous fluids confined in a nanopore using molecular dynamics simulations. the fluid is modeled by core - softened ( cs ) potentials that have a repulsive shoulder and an attractive well at a further distance. changing the attractive well depth of the fluid - fluid interaction potential, we studied the behavior of the anomalies in the translational order parameter $ t $ and excess entropy $ s _ { ex } $ for the particles near to the nanopore wall ( contact layer ) for systems with two or three layers of particles. when the attractive well of the cs potential is shallow, the systems present a three to two layers transition and, additionally to the usual structural anomaly, a new anomalous region in $ t $ and $ s _ { ex } $. for attractive well deep enough, the systems change from three layers to a bulk - like profile and just one region of anomaly in $ t $ and $ s _ { ex } $ is observed. our results are discussed in the basis of the fluid - fluid and fluid - surface interactions. | arxiv:1410.5525 |
nowadays, the development of web applications supporting distributed user interfaces ( dui ) is straightforward. however, it is still hard to find web sites supporting this kind of user interaction. although studies on this field have demonstrated that dui would improve the user experience, users are not massively empowered to manage these kinds of interactions. in this setting, we propose to move the responsibility of distributing both the ui and user interaction, from the application ( a web application ) to the client ( the web browser ), giving also rise to inter - application interaction distribution. this paper presents a platform for client - side dui, built on the foundations of web augmentation and end user development. the idea is to empower end users to apply an augmentation layer over existing web applications, considering both frequent use and opportunistic dui requirements. in this work, we present the architecture and a prototype tool supporting this approach and illustrate the incorporation of some dui features through case studies. | arxiv:1906.01410 |
we present a direct detection of the stellar halo of the edge - on s0 galaxy ngc 3957, using ultra - deep vlt / vimos v and r images. this is achieved with a sky subtraction strategy based on infrared techniques. these observations allow us to reach unprecedented high signal - to - noise ratios up to 15 kpc away from the galaxy center, rendering photon - noise negligible. the 1 sigma detection limits are r = 30. 6 mag / arcsec ^ 2 and v = 31. 4 mag / arcsec ^ 2. we conduct a thorough analysis of the possible sources of systematic errors that could affect the data : flat - fielding, differences in ccd responses, scaling of the sky background, the extended halo itself, and psf wings. we conclude that the v - r colour of the ngc 3957 halo, calculated between 5 and 8 kpc above the disc plane where the systematic errors are modest, is consistent with an old and preferentially metal - poor normal stellar population, like that revealed in nearby galaxy halos from studies of their resolved stellar content. we do not find support for the extremely red colours found in earlier studies of diffuse halo emission, which we suggest might have been due to residual systematic errors. | arxiv:1001.3067 |
relativistic coupled - cluster calculations of the ionization potential, dissociation energy, and excited electronic states under 35, 000 cm $ ^ { - 1 } $ are presented for the actinium monofluoride ( acf ) molecule. the ionization potential is calculated to be ip $ _ e = 48, 866 $ cm $ ^ { - 1 } $, and the ground state is confirmed to be a closed - shell singlet and thus strongly sensitive to the $ \ mathcal { t } $, $ \ mathcal { p } $ - violating nuclear schiff moment of the ac nucleus. radiative properties and transition dipole moments from the ground state are identified for several excited states, achieving an uncertainty of $ \ sim $ 450 cm $ ^ { - 1 } $ for the excitation energies. for higher - lying states that are not directly accessible from the ground state, possible two - step excitation pathways are proposed. the calculated branching ratios and franck - condon factors are used to investigate the suitability of acf for direct laser cooling. the lifetime of the metastable $ ( 1 ) ^ 3 \ delta _ 1 $ state, which can be used in experimental searches of the electric dipole moment of the electron, is estimated to be of order 1 ms. | arxiv:2305.06932 |
this paper proposes a joint channel and data estimation ( jcde ) algorithm for uplink multiuser extremely large - scale multiple - input - multiple - output ( xl - mimo ) systems. the initial channel estimation is formulated as a sparse reconstruction problem based on the angle and distance sparsity under the near - field propagation condition. this problem is solved using non - orthogonal pilots through an efficient low complexity two - stage compressed sensing algorithm. furthermore, the initial channel estimates are refined by employing a jcde framework driven by both non - orthogonal pilots and estimated data. the jcde problem is solved by sequential expectation propagation ( ep ) algorithms, where the channel and data are alternately updated in an iterative manner. in the channel estimation phase, integrating bayesian inference with a model - based deterministic approach provides precise estimations to effectively exploit the near - field characteristics in the beam - domain. in the data estimation phase, a linear minimum mean square error ( lmmse ) - based filter is designed at each sub - array to address the correlation due to energy leakage in the beam - domain arising from the near - field effects. numerical simulations reveal that the proposed initial channel estimation and jcde algorithm outperforms the state - ofthe - art approaches in terms of channel estimation, data detection, and computational complexity. | arxiv:2406.19289 |
in this paper we examine methods for taking game - related information provided in one sensory modality and transforming it to another sensor modality in order to more effectively accommodate sensory - constrained players. we then consider methods for the adaptation and design of games for which gameplay interactions are constrained to a subset of sensory modalities in ways that preserve a common level of novelty - of - experience for players with different sensory capabilities. it is hoped that improved shared experiences can promote interactions among a more diverse spectrum of players. | arxiv:2106.09763 |
we initiate the classification of unitary superconformal defects in unitary superconformal field theories ( scft ) of diverse spacetime dimensions $ 3 \ leq d \ leq 6 $. our method explores general constraints from the defect superconformal symmetry, unitarity, as well as consistency conditions of local bulk - defect couplings. such features are common to all superconformal defects regardless of any lagrangian description. in particular, modified ward identities of conserved currents in the presence of the defect induce a distinguished set of conformal primary operators on the defect worldvolume, which includes the universal displacement operator associated with broken translations transverse to the defect. consistency with the preserved superconformal symmetry and unitarity requires that such operators arrange into unitarity multiplets of the defect superconformal algebra, which in turn leads to nontrivial constraints on what kinds of defects are admissible in a given scft. we carry out the analysis explicitly for one - dimensional defects, namely superconformal lines, and leave the study of higher dimensional defects to forthcoming work. we also comment on the implications of our results for the deformations of superconformal lines and one - form symmetries in scfts. | arxiv:2009.06650 |
we prove an optimal mixing time bound on the single - site update markov chain known as the glauber dynamics or gibbs sampling in a variety of settings. our work presents an improved version of the spectral independence approach of anari et al. ( 2020 ) and shows $ o ( n \ log { n } ) $ mixing time on any $ n $ - vertex graph of bounded degree when the maximum eigenvalue of an associated influence matrix is bounded. as an application of our results, for the hard - core model on independent sets weighted by a fugacity $ \ lambda $, we establish $ o ( n \ log { n } ) $ mixing time for the glauber dynamics on any $ n $ - vertex graph of constant maximum degree $ \ delta $ when $ \ lambda < \ lambda _ c ( \ delta ) $ where $ \ lambda _ c ( \ delta ) $ is the critical point for the uniqueness / non - uniqueness phase transition on the $ \ delta $ - regular tree. more generally, for any antiferromagnetic 2 - spin system we prove $ o ( n \ log { n } ) $ mixing time of the glauber dynamics on any bounded degree graph in the corresponding tree uniqueness region. our results apply more broadly ; for example, we also obtain $ o ( n \ log { n } ) $ mixing for $ q $ - colorings of triangle - free graphs of maximum degree $ \ delta $ when the number of colors satisfies $ q > \ alpha \ delta $ where $ \ alpha \ approx 1. 763 $, and $ o ( m \ log { n } ) $ mixing for generating random matchings of any graph with bounded degree and $ m $ edges. | arxiv:2011.02075 |
we linearize the artin representation of the braid group given by ( right ) automorphisms of a free group providing a linear faithful representation of the braid group. this result is generalized to obtain linear representations for the coloured braid groupoid and pure braid group too. applications to some areas of two - dimensional physics are discussed. | arxiv:hep-th/9210020 |
a qualitative calculation and discussion of two vortex states collisions are given in the scalar $ \ phi ^ 4 $ model. three kinds of vortex states - - bessel, general monochromatic, and laguerre - gaussian vortex states - - are considered. it is found that the total final momentum distribution in collision of physical vortex states displays general topological structures, which depend on the initial vortex states ' topological charges, which are proportional to the orbital angular momenta. this peculiar matching provides a novel observable, the topological number of momentum distribution, and it may represent a new fascinating research direction in particle physics. we also find that the situation when the angular momenta of the two colliding laguerre - gaussian states combine to zero can be recognized by the total final momentum distribution close to the collision axis. both features can be used to measure the orbital angular momentum of vortex states. | arxiv:2312.00424 |
neutrinoless double beta decay can significantly help to shed light on the issue of non - zero neutrino mass, as observation of this lepton number violating process would imply neutrinos are majorana particles. however, the underlying interaction does not have to be as simple as the standard neutrino mass mechanism. the entire variety of neutrinoless double beta decay mechanisms can be approached effectively. in this work we focus on a theoretical description of short - range effective contributions to neutrinoless double beta decay, which are equivalent to 9 - dimensional effective operators incorporating the appropriate field content. we give a detailed derivation of the nuclear matrix elements and phase space factors corresponding to individual terms of the effective lagrangian. using these, we provide general formulae for the neutrinoless double beta decay half - life and angular correlation of the outgoing electrons. | arxiv:1806.06058 |
we consider a simple massive extension of the landau - dewitt gauge for su ( $ n $ ) yang - mills theory. we compute the corresponding one - loop effective potential for a temporal background gluon field at finite temperature. at this order the background field is simply related to the polyakov loop, the order parameter of the deconfinement transition. our perturbative calculation correctly describes a quark confining phase at low temperature and a phase transition of second order for $ n = 2 $ and weakly first order for $ n = 3 $. our estimates for the transition temperatures are in qualitative agreement with values from lattice simulations or from other continuum approaches. finally, we discuss the effective gluon mass parameter in relation to the gribov ambiguities of the landau - dewitt gauge. | arxiv:1407.6469 |
in this article, we deal with fractional stochastic differential equations, so - called caputo type fractional backward stochastic differential equations ( caputo fbsdes, for short ), and study the well - posedness of an adapted solution to caputo fbsdes of order $ \ alpha \ in ( \ frac { 1 } { 2 }, 1 ) $ whose coefficients satisfy a lipschitz condition. a novelty of the article is that we introduce a new weighted norm in the square integrable measurable function space that is useful for proving a fundamental lemma and its well - posedness. for this class of systems, we then show the coincidence between the notion of stochastic volterra integral equation and the mild solution. | arxiv:2109.11461 |
we study the closure of the convex hull of a compact set in a complete cat ( 0 ) space. first we give characterization results in terms of compact sets and the closure of their convex hulls for locally compact cat ( 0 ) spaces that are either regular or satisfy the geodesic extension property. later inspired by a geometric interpretation of carath \ ' eodory ' s theorem we introduce the operation of threading for a given set. we show that threading exhibits certain monotonicity properties with respect to intersection and union of sets. moreover threading preserves compactness. next from the commutativity of threading with any isometry mapping we prove that in a flat complete cat ( 0 ) space the closure of the convex hull of a compact set is compact. we apply our theory to the computability of the fr \ ' echet mean of a finite set of points and show that it is constructible in at most a finite number of steps, whenever the underlying space is of finite type. | arxiv:2109.06002 |
this work introduces a novel graph neural networks ( gnns ) - based method to predict stream water temperature and reduce model bias across locations of different income and education levels. traditional physics - based models often have limited accuracy because they are necessarily approximations of reality. recently, there has been an increasing interest of using gnns in modeling complex water dynamics in stream networks. despite their promise in improving the accuracy, gnns can bring additional model bias through the aggregation process, where node features are updated by aggregating neighboring nodes. the bias can be especially pronounced when nodes with similar sensitive attributes are frequently connected. we introduce a new method that leverages physical knowledge to represent the node influence in gnns, and then utilizes physics - based influence to refine the selection and weights over the neighbors. the objective is to facilitate equitable treatment over different sensitive groups in the graph aggregation, which helps reduce spatial bias over locations, especially for those in underprivileged groups. the results on the delaware river basin demonstrate the effectiveness of the proposed method in preserving equitable performance across locations in different sensitive groups. | arxiv:2412.16523 |
we study distribution - free property testing and learning problems where the unknown probability distribution is a product distribution over $ \ mathbb { r } ^ d $. for many important classes of functions, such as intersections of halfspaces, polynomial threshold functions, convex sets, and $ k $ - alternating functions, the known algorithms either have complexity that depends on the support size of the distribution, or are proven to work only for specific examples of product distributions. we introduce a general method, which we call downsampling, that resolves these issues. downsampling uses a notion of " rectilinear isoperimetry " for product distributions, which further strengthens the connection between isoperimetry, testing, and learning. using this technique, we attain new efficient distribution - free algorithms under product distributions on $ \ mathbb { r } ^ d $ : 1. a simpler proof for non - adaptive, one - sided monotonicity testing of functions $ [ n ] ^ d \ to \ { 0, 1 \ } $, and improved sample complexity for testing monotonicity over unknown product distributions, from $ o ( d ^ 7 ) $ [ black, chakrabarty, & seshadhri, soda 2020 ] to $ \ widetilde o ( d ^ 3 ) $. 2. polynomial - time agnostic learning algorithms for functions of a constant number of halfspaces, and constant - degree polynomial threshold functions. 3. an $ \ exp ( o ( d \ log ( dk ) ) ) $ - time agnostic learning algorithm, and an $ \ exp ( o ( d \ log ( dk ) ) ) $ - sample tolerant tester, for functions of $ k $ convex sets ; and a $ 2 ^ { \ widetilde o ( d ) } $ sample - based one - sided tester for convex sets. 4. an $ \ exp ( \ widetilde o ( k \ sqrt d ) ) $ - time agnostic learning algorithm for $ k $ - alternating functions, and a sample - based tolerant tester with the same complexity. | arxiv:2007.07449 |
dark matter ( dm ) and neutrinos are the two most compelling pieces of evidence of new physics beyond the standard model of particle physics but these are often treated as belonging to two different sectors. yet dm - neutrino interactions are known to have cosmological consequences. here, we study the scenario of a scalar dm candidate coupled to left - handed neutrinos via a dirac mediator. we determine the mass of a dm candidate that yields the right dm relic abundance in a thermal scenario and it is consistent with large - scale structure formation. in order to satisfy both constraints, a complex dm candidate should have a mass larger than $ 8. 14 $ kev while the mass of a real dm candidate should be above $ 18. 1 $ ev, independently of the value of the dm - neutrino coupling. | arxiv:1705.03692 |
measuring personal disclosures made in human - chatbot interactions can provide a better understanding of users ' ai literacy and facilitate privacy research for large language models ( llms ). we run an extensive, fine - grained analysis on the personal disclosures made by real users to commercial gpt models, investigating the leakage of personally identifiable and sensitive information. to understand the contexts in which users disclose to chatbots, we develop a taxonomy of tasks and sensitive topics, based on qualitative and quantitative analysis of naturally occurring conversations. we discuss these potential privacy harms and observe that : ( 1 ) personally identifiable information ( pii ) appears in unexpected contexts such as in translation or code editing ( 48 % and 16 % of the time, respectively ) and ( 2 ) pii detection alone is insufficient to capture the sensitive topics that are common in human - chatbot interactions, such as detailed sexual preferences or specific drug use habits. we believe that these high disclosure rates are of significant importance for researchers and data curators, and we call for the design of appropriate nudging mechanisms to help users moderate their interactions. | arxiv:2407.11438 |
magnetic domain walls are topological solitons whose internal structure is set by competing energies which sculpt them. in common ferromagnets, domain walls are known to be of either bloch or n \ ' eel types. little is established in the case of mn $ _ 3 $ sn, a triangular antiferromagnet with a large room - temperature anomalous hall effect, where domain nucleation is triggered by a well - defined threshold magnetic field. here, we show that the domain walls of this system generate an additional contribution to the hall conductivity tensor and a transverse magnetization. the former is an electric field lying in the same plane with the magnetic field and electric current and therefore a planar hall effect. we demonstrate that in - plane rotation of spins inside the domain wall would explain both observations and the clockwise or anticlockwise chirality of the walls depends on the history of the field orientation and can be controlled. | arxiv:1903.03774 |
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