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this paper proposes three measures to quantify the characteristics of online signature templates in terms of distinctiveness, complexity and repeatability. a distinctiveness measure of a signature template is computed from a set of enrolled signature samples and a statistical assumption about random signatures. secondly, a complexity measure of the template is derived from a set of enrolled signature samples. finally, given a signature template, a measure to quantify the repeatability of the online signature is derived from a validation set of samples. these three measures can then be used as an indicator for the performance of the system in rejecting random forgery samples and skilled forgery samples and the performance of users in providing accepted genuine samples, respectively. the effectiveness of these three measures and their applications are demonstrated through experiments performed on three online signature datasets and one keystroke dynamics dataset using different verification algorithms.
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arxiv:1808.03399
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we review the relation between the " embedding " formalism and spinorial projective space. the latter is more convenient when treating spin ( and indispensable for supersymmetry ), as it maintains manifest conformal symmetry while using 4 - dimensional indices on fields / operators. it does this by solving all algebraic constraints using 6 - dimensional ( off - shell ) twistors. in an added note we review the supersymmetric generalization, and give some new results for n = 3.
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arxiv:1204.5679
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these notes review six lectures given by prof. andrea montanari on the topic of statistical estimation for linear models. the first two lectures cover the principles of signal recovery from linear measurements in terms of minimax risk. subsequent lectures demonstrate the application of these principles to several practical problems in science and engineering. specifically, these topics include denoising of error - laden signals, recovery of compressively sensed signals, reconstruction of low - rank matrices, and also the discovery of hidden cliques within large networks.
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arxiv:1409.5557
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we demonstrate the utility of raman spectroscopy as a technique for the identification of ancient glasses and enamel coatings of ceramics. as for any silicate glasses, the addition of network modifiers breaks the si - o linkages and modifies the degree of polymerisation and hence the relative intensity of the si - o bending and stretching modes. we demonstrate empirically that the ratio of these envelopes is well correlated to the glass structure and to the used firing technology. spectral qn components assigned to isolated and connected sio4 vibrational units allow more precise analysis. selected porcelains, faiences, potteries and glasses representative of the different asian, islamic and european production technologies were studied. modern porcelain enamels are used as compositional references.
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arxiv:cond-mat/0701414
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we suggest a spatially local feedback mechanism for stabilizing periodic orbits in spatially extended systems. our method, which is based on a comparison between present and past states of the system, does not require the external generation of an ideal reference state and can suppress both absolute and convective instabilities. as an example, we analyze the complex ginzburg - landau equation in one dimension, showing how the time - delay feedback enlarges the stability domain for travelling waves.
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arxiv:chao-dyn/9601006
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the covid - 19 pandemic had profoundly changed the way we lived and perceived our lives. the successful delivery of vaccines together with relentless effort from all stakeholders helped us to ` ` reclaim our normal way life ' '. in this article, we propose a mathematical model that incorporates most features of covid - 19 transmission dynamics to investigate the contribution of vaccines to control the pandemic. the basic reproduction number of the model, denoted by $ \ mathcal { r } _ 0 $ is calculated. during imperfect vaccination and recovery does not lead into permanent immunity, we have shown that the model could exhibit a backward bifurcation when $ \ mathcal { r } _ 0 < 1 $. with perfect vaccination and recovery guarantees permanent immunity, the disease - free equilibrium is globally asymptotically stable for $ \ mathcal { r } _ 0 < 1 $ and unstable for $ \ mathcal { r } _ 0 > 1 $. numerical experiments are also conducted to support the theoretical analysis. the model is fitted into a real data from open sources and the sensitivity analysis of the basic reproduction number with respect to involved parameters is done to identify the most sensitive parameters for control intervention. finally, we conclude from the numerical experiments that vaccines have significantly improved the recovery rate from covid - 19 infection but do not offer complete protection protection.
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arxiv:2311.18369
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we study the behaviour of the geometric phase under isometries of the ray space. this leads to a better understanding of a theorem first proved by wigner : isometries of the ray space can always be realised as projections of unitary or anti - unitary transformations on the hilbert space. we suggest that the construction involved in wigner ' s proof is best viewed as an use of the pancharatnam connection to ` ` lift ' ' a ray space isometry to the hilbert space.
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arxiv:quant-ph/9705019
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the color structure needed for resummation of all colored 2 - > 3 processes is calculated using multiplet inspired s - channel bases. in this way the resulting matrices, describing the color structure, are guaranteed to obey simplifying symmetries.
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arxiv:0807.0555
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in high - dimensional and / or non - parametric regression problems, regularization ( or penalization ) is used to control model complexity and induce desired structure. each penalty has a weight parameter that indicates how strongly the structure corresponding to that penalty should be enforced. typically the parameters are chosen to minimize the error on a separate validation set using a simple grid search or a gradient - free optimization method. it is more efficient to tune parameters if the gradient can be determined, but this is often difficult for problems with non - smooth penalty functions. here we show that for many penalized regression problems, the validation loss is actually smooth almost - everywhere with respect to the penalty parameters. we can therefore apply a modified gradient descent algorithm to tune parameters. through simulation studies on example regression problems, we find that increasing the number of penalty parameters and tuning them using our method can decrease the generalization error.
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arxiv:1703.09813
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due to the high anticipated experimental precision at the future circular collider fcc - ee ( or other proposed $ e ^ + e ^ - $ colliders, such as ilc, clic, or cepc ) for electroweak and higgs - boson precision measurements, theoretical uncertainties may have, if unattended, an important impact on the interpretation of these measurements within the standard model ( sm ), and thus on constraints on new physics. current theory uncertainties, which would dominate the total uncertainty, need to be strongly reduced through future advances in the calculation of multi - loop radiative corrections together with improved experimental and theoretical control of the precision of sm input parameters. this document aims to provide an estimate of the required improvement in calculational accuracy in view of the anticipated high precision at the fcc - ee. for the most relevant electroweak and higgs - boson precision observables we evaluate the corresponding quantitative impact.
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arxiv:1906.05379
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we describe and explain the desire, common among mathematicians, both for unity and independence in its major themes. in the dialogue that follows, we express our spontaneous and considered judgment and reservations by contrasting the development of mathematics as a goal - driven process as opposed to one that often seems to possess considerable arbitrariness.
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arxiv:1204.5143
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contributing to oss projects can help students to enhance their skills and expand their professional networks. however, novice contributors often feel discouraged due to various barriers. gamification techniques hold the potential to foster engagement and facilitate the learning process. nevertheless, it is unknown which game elements are effective in this context. this study explores students ' perceptions of gamification elements to inform the design of a gamified learning environment. we surveyed 115 students and segmented the analysis from three perspectives : ( 1 ) cognitive styles, ( 2 ) gender, and ( 3 ) ethnicity ( hispanic / latinx and non - hispanic / latinx ). the results showed that quest, point, stats, and badge are favored elements, while competition and pressure - related are less preferred. across cognitive styles ( persona ), gender, and ethnicity, we could not observe any statistical differences, except for tim ' s gendermag persona, which demonstrated a higher preference for storytelling. conversely, hispanic / latinx participants showed a preference for the choice element. these results can guide tool builders in designing effective gamified learning environments focused on the oss contributions process.
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arxiv:2407.04674
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most of the discussion regarding the higgs boson couplings to standard model vector bosons and fermions is presented with respect to what present and future collider detectors will be able to measure. here, we ask the more physics - based question of how well do we need to measure the higgs boson couplings? we first present a reasonable definition of " need " and then investigate the answer in the context of various highly motivated new physics scenarios : supersymmetry, mixed - in hidden sector higgs bosons, and a composite higgs boson. we find the largest coupling deviations away from the sm higgs couplings that are possible if no other state related to ewsb is directly accessible at the lhc. depending on the physics scenario under consideration, we find targets that range from less than 1 % to 10 % for vector bosons, and from a few percent to tens of percent for couplings to fermions.
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arxiv:1206.3560
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we present a method that combines continuous and pulsed microwave radiation patterns to achieve robust interactions among hyperfine trapped ions placed in a magnetic field gradient. more specifically, our scheme displays continuous microwave drivings with modulated phases, phase flips, and $ \ pi $ pulses. this leads to high - fidelity entangling gates which are resilient against magnetic field fluctuations, changes on the microwave amplitudes, and crosstalk effects. our protocol runs with arbitrary values of microwave power, which includes the technologically relevant case of low microwave intensities. we demonstrate the performance of our method with detailed numerical simulations that take into account the main sources of decoherence.
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arxiv:1911.03144
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we analyze the conradi - kahle algorithm for detecting binomiality. we present experiments using two implementations of the algorithm in macaulay2 and maple on biological models and assess the performance of the algorithm on these models. we compare the two implementations with each other and with gr \ " obner bases computations up to their performance on these biological models.
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arxiv:1912.06896
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in this letter we explore, both experimentally and theoretically, the existence in the millimeter wave range of the phenomenon of extraordinary light transmission though arrays of subwavelength holes. we have measured the transmission spectra of several samples made on aluminum wafers by using an ab millimetre quasioptical vector network analyzer in the wavelength range between 4. 2mm to 6. 5mm. clear signals of the existence of resonant light transmission at wavelengths close to the period of the array appear in the spectra.
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arxiv:cond-mat/0311036
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habitable planets are often defined as terrestrial worlds capable of maintaining surface liquid water. as a result, atmospheric water vapor can be a critical indicator of habitability. thus, habitability - themed exoplanet investigations emphasize detection of water vapor signatures for their targets. a variety of concept missions for exoplanet direct imaging in reflected light have seen recent study, including the habex and luvoir concepts. here, it is important to understand how direct imaging in reflected light - - - coupled with moderate - resolution spectroscopy - - - could be used to detect various water vapor amounts in earth - like exoplanetary atmospheres. to investigate water vapor detection for terrestrial exoplanets, we generated reflectance spectra over a grid of water vapor column masses and used an instrument model to explore requisite integration times for spectral feature detection at either visible or near - infrared wavelengths. lower - resolution near - infrared spectroscopy is generally optimal for detecting water vapor in the atmospheres of earth - like exoplanets when using direct imaging in reflected light. this holds true for dry or cold terrestrial planets, whose atmospheres would contain relatively little water vapor. atmospheres richer in water vapor, such as planets undergoing a moist or runaway greenhouse, could have water vapor efficiently detected at visible wavelengths. understanding details like an exoplanet ' s size, temperature, and location relative to the habitable zone can aid in determining appropriate wavelength ranges for atmospheric characterization. overall, water vapor detection for earth - like exoplanets is quite feasible for future direct imaging missions.
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arxiv:1912.02228
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repeaterless low swing interconnects use mixed signal circuits to achieve high performance at low power. when these interconnects are used in large scale and high volume digital systems their testability becomes very important. this paper discusses the testability of low swing repeaterless on - chip interconnects with equalization and clock synchronization. a capacitively coupled transmitter with a weak driver is used as the transmitter. the receiver samples the low swing input data at the center of the data eye and converts it to rail to rail levels and also synchronizes the data to the receiver ' s clock domain. the system is a mixed signal circuit and the digital components are all scan testable. for the analog section, just a dc test has a fault coverage of 50 % of the structural faults. simple techniques allow integration of the analog components into the digital scan chain increasing the coverage to 74 %. finally, a bist with low overhead enhances the coverage to 95 % of the structural faults. the design and simulations have been done in umc 130 nm cmos technology.
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arxiv:1511.06726
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plane poiseuille flow past a nanoscale cylinder that is arbitrarily confined ( i. e., symmetrically or asymmetrically confined ) in a slit channel is studied via hydrodynamic lubrication theory and molecular dynamics simulations, considering cases where the cylinder remains static or undergoes thermal motion. lubrication theory predictions for the drag force and volumetric flow rate are in close agreement with molecular dynamics simulations of flows having molecularly thin lubrication gaps, despite the presence of significant structural forces induced by the crystalline structure of the modeled solid. while the maximum drag force is observed in symmetric confinement, i. e., when the cylinder is equidistant from both channel walls, the drag decays significantly as the cylinder moves away from the channel centerline and approaches a wall. hence, significant reductions in the mean drag force on the cylinder and hydraulic resistance of the channel can be observed when thermal motion induces random off - center displacements. analytical expressions and numerical results in this work provide useful insights into the hydrodynamics of colloidal solids and macromolecules in confinement.
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arxiv:1504.03050
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since key comparison cct - k2, only few comparisons on realizations of cryogenic fixed points have been carried out, be they bilateral ( three, of which one still pending ) or multilateral ( two trilateral ). since a forthcoming general follow - up is unlikely, any bilateral comparison, not only key comparisons, is most welcome to provide evidence of the continuing thermometric capabilities of the laboratories involved in the realization of the its - 90. not too long after the creation in 2018 of the joint research laboratory for fluid metrology evangelista torricelli between lne - cnam and inrim, the two laboratories agreed to perform a bilateral comparison at all the cryogenic fixed points of the scale between 13 k and 273 k, including the two hydrogen vapour - pressure temperatures required for the full platinum resistance thermometer range 3. 3. 1 of the its - 90. the results are reported here and show a substantial agreement, within the combined uncertainties.
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arxiv:2007.11340
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starting from the molecular picture for the $ d _ { s1 } ( 2460 ) $ and $ d _ { s1 } ( 2536 ) $ resonances, which are dynamically generated by the interaction of coupled channels, the most important of which are the $ d ^ * k $ for the $ d _ { s1 } ( 2460 ) $ and $ dk ^ * $ for the $ d _ { s1 } ( 2536 ) $, we evaluate the ratio of decay widths for the $ \ bar { b } _ s ^ 0 \ to d _ { s1 } ( 2460 ) ^ + k ^ - $ and $ \ bar { b } _ s ^ 0 \ to d _ { s1 } ( 2536 ) ^ + k ^ - $ decays, the latter of which has been recently investigated by the lhcb collaboration, and we obtain a ratio of the order of unity. the present results should provide an incentive for the related decay into the $ d _ { s1 } ( 2460 ) $ resonance to be performed, which would provide valuable information on the nature of these two resonances.
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arxiv:2401.04587
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due to the complexity of the human body and its neuromuscular stabilization, it has been challenging to efficiently and accurately predict human motion and capture posture while being driven. existing simple models of the seated human body are mostly two - dimensional and developed in the mid - sagittal plane ex - posed to in - plane excitation. such models capture fore - aft and vertical motion but not the more complex 3d motions due to lateral loading. advanced 3d full - body active human models ( ahms ), such as in madymo, can be used for comfort analysis and to investigate how vibrations influence the human body while being driven. however, such ahms are very time - consuming due to their complexity. to effectively analyze motion comfort, a computationally efficient and accurate three dimensional ( 3d ) human model, which runs faster than real - time, is presented. the model ' s postural stabilization parameters are tuned using available 3d vibration data for head, trunk and pelvis translation and rotation. a comparison between ahm and ehm is conducted regarding human body kinematics. according to the results, the ehm model configuration with two neck joints, two torso bending joints, and a spinal compression joint accurately predicts body kinematics.
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arxiv:2306.12279
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in this paper we propose and study a hybrid discrete in continuous mathematical model of collective motion under alignment and chemotaxis effect. starting from the paper by di costanzo et al ( 2015a ), in which the cucker - smale model ( cucker and smale, 2007 ) was coupled with other cell mechanisms, to describe the cell migration and self - organization in the zebrafish lateral line primordium, we introduce a simplified model in which the coupling between an alignment and chemotaxis mechanism acts on a system of interacting particles. in particular we rely on a hybrid description in which the agents are discrete entities, while the chemoattractant is considered as a continuous signal. the proposed model is then studied both from an analytical and a numerical point of view. from the analytic point of view we prove, globally in time, existence and uniqueness of the solution. then, the asymptotic behaviour of a linearised version of the system is investigated. through a suitable lyapunov functional we show that for $ t \ rightarrow + \ infty $, the migrating aggregate exponentially converges to a state in which all the particles have a same position with zero velocity. finally, we present a comparison between the analytical findings and some numerical results, concerning the behaviour of the full nonlinear system.
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arxiv:1507.02980
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dissipative mechanical systems on the torus with a friction that is proportional to the velocity are modeled by conformally symplectic maps on the annulus, which are maps that transport the symplectic form into a multiple of itself ( with a conformal factor smaller than 1 ). it is important to understand the structure and the dynamics on the attractors. with the aid of parameters, and under suitable non - degeneracy conditions, one can obtain that, by adjusting parameters, there is an attractor that is an invariant torus whose internal dynamics is conjugate to a rotation [ ccdll13 ]. by analogy with symplectic dynamics, there have been some debate in establishing appropriate definitions for twist and non - twist invariant tori ( or systems ). the purpose of this paper is two - fold : ( a ) to establish proper definitions of twist and non - twist invariant tori in families of conformally symplectic systems ; ( b ) to derive algorithms of computation of non - twist invariant tori. the last part of the paper is devoted to implementations of the algorithms, illustrating the definitions presented in this paper, and exploring the mechanisms of breakdown of non - twist tori. for the sake of simplicity we have considered here 2d systems, i. e. defined in the 2d annulus, but generalization to higher dimensions is straightforward.
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arxiv:2005.09754
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we reconstruct quantum mechanics by introducing " information operators " and excluding the concept of wave functions. multiple information operators simultaneously describe a single system and continuously develop in time even in the process of a measurement. we also introduce the concept of condensation for a system with many degrees of freedom in a rather general meaning. in terms of the multiplicity of description and the condensation, we explain quantum phenomena including measurements without the collapse of the wave function.
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arxiv:0808.0249
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in this chapter, we discuss the effects of higher - order structures on sis - like processes of social contagion. after a brief motivational introduction where we illustrate the standard sis process on networks and the difference between simple and complex contagions, we introduce spreading processes on higher - order structures starting from the most general formulation on hypergraphs and then moving to several mean - field and heterogeneous mean - field approaches. the results highlight the rich phenomenology brought by taking into account higher - order contagion effects : both continuous and discontinuous transitions are observed, and critical mass effects emerge. we conclude with a short discussion on the theoretical results regarding the nature of the epidemic transition and the general need for data to validate these models.
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arxiv:2103.03709
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we report the analysis of the high - resolution soft x - ray spectrum of the nearby f - type star procyon in the wavelength range from 5 to 175 angstrom obtained with the low energy transmission grating spectrometer ( letgs ) on board chandra and with the reflection grating spectrometers ( rgs ) and the epic - mos ccd spectrometers on board xmm - newton. line fluxes have been measured separately for the rgs and letgs. spectra have been fitted globally to obtain self - consistent temperatures, emission measures, and abundances. the total volume emission measure is ~ 4. 1 x 10e50 / cm3 with a peak between 1 and 3 mk. no indications for a dominant hot component ( t > 4 mk ) were found. we present additional evidence for the lack of a solar - type fip - effect, confirming earlier euve results.
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arxiv:astro-ph/0204385
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the value of excess charge in the kernel of massive body ( and the opposite in sign excess charge at the surface ) caused by the influence of gravitational forces is determined.
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arxiv:astro-ph/9902121
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this paper presents a combinatorial study of sums of integer powers of the cotangent which is a popular theme in classical calculus. our main tool the realization of cotangent values as eigenvalues of a simple self - adjoint matrix with integer matrix. we use the trace method to draw conclusions about integer values of the sums and expand generating functions to obtain explicit evaluations. it is remarkable that throughout the calculations the combinatorics are governed by the higher tangent and arctangent numbers exclusively. finally we indicate a new approximation of the values of the riemann zeta function at even integer arguments.
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arxiv:2002.06052
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the geometric satake isomorphism is an equivalence between the categories of spherical perverse sheaves on affine grassmanian and the category of representations of the langlands dual group. we provide a similar description for derived categories of l - adic sheaves on an affine flag variety which are geometric counterparts of a maximal commutative subalgebra in the iwahori hecke algebra ; of the anti - spherical module over this algebra ; and of the space of iwahori - invariant whitakker functions.
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arxiv:math/0201073
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magneto optical trap recoil ion momentum spectroscopy is used to measure energy - dependent charge exchange cross sections in the cs + + rb ( 5s, 5p ) system over a range of projectile energies from 3. 2 to 6. 4 kev. the measurements are kinematically complete and yield cross sections that are differential in collision energy, scattering angle, and initial and final states.
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arxiv:1306.4112
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we present a spin - induced none - geodesic effect of dirac wave packets in a static uniform gravitational field. our approach is based on the foldy - wouthuysen transformation of dirac equation in a curved spacetime, which predicts the gravitational spin - orbit coupling. due to this coupling, we find that the dynamics of the free - fall dirac wave packets with opposite spin polarization will yield the transverse splitting in the direction perpendicular to spin orientation and gravity, which is known as the gravitational spin hall effect. even in a static uniform gravitational field, such effect suggests that the weak equivalence principle is violated for quantum particles.
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arxiv:2310.17581
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we investigate birationality of the anti - pluricanonical map $ \ phi _ { - m } $, the rational map defined by the anti - pluricanonical system $ | - mk | $, on $ \ mathbb { q } $ - fano threefolds.
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arxiv:0901.0413
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we test whether the structural properties of the nearby dwarf spheroidal ( dsph ) galaxy draco, a well - studied milky way companion, can be reconciled with the suggestion that dsphs are unbound tidal remnants with a large depth extent along the line of sight. in order to apply the observational test of this hypothesis suggested by klessen & zhao, we use public photometric data from the sloan digital sky survey ( sdss ) to explore the width of draco ' s blue horizontal branch over a range of areas covering 0. 06 square degrees to 6. 25 square degrees centered on draco. the sdss database is the only currently existing database with sufficient depth and area coverage to permit a stringent test of the tidal models. we show that blue horizontal branch stars extend beyond the previously inferred limiting radii of draco, consistent with the observed absence of a truncated stellar surface density profile of this dsph. we calculate new models for a galaxy without dark matter, using draco ' s morphological properties as constraints. the resulting models are unable to reproduce the narrow observed horizontal branch width of draco, which stays roughly constant regardless of the field of view. we conclude that draco cannot be the remnant of a tidally disrupted satellite, but is probably strongly dark - matter dominated. ( abstract abbreviated )
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arxiv:astro-ph/0302287
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in gauge - higgs unification the 4d higgs boson appears as a part of the fifth dimensional component of gauge potentials, namely as a fluctuation mode of the aharonov - bohm phase in the extra dimension. the $ so ( 5 ) \ times u ( 1 ) \ times su ( 3 ) $ gauge - higgs unification gives nearly the same phenomenology as the standard model ( sm ) at low energies. it predicts kk excited states of photon, $ z $ boson, and $ z _ r $ boson ( $ z ' $ bosons ) around 7 - 8 tev. quarks and leptons couple to these $ z ' $ bosons with large parity violation, which leads to distinct interference effects in $ e ^ + e ^ - \ rightarrow \ mu ^ + \ mu ^ -, q \, \ bar q $ processes. at 250 gev ilc with polarized electron beams, deviation from sm can be seen at the 3 - 5 sigma level even with 250 fb $ ^ { - 1 } $ data, namely in the early stage of ilc. signals become stronger at higher energies. precision measurements of interference effects at electron - positron colliders at energies above 250 gev become very important to explore physics beyond the standard model.
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arxiv:1904.10156
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observations show that the lower thermosphere of mars ( $ \ sim $ 100 - - 140 km ) is up to 40 k colder than the current general circulation models ( gcms ) can reproduce. possible candidates for physical processes missing in the models are larger abundances of atomic oxygen facilitating stronger co $ _ 2 $ radiative cooling, and thermal effects of gravity waves. using two state - of - the - art martian gcms, the laboratoire de m \ ' et \ ' eorologie dynamique and max planck institute models that self - consistently cover the atmosphere from the surface to the thermosphere, these physical mechanisms are investigated. simulations demonstrate that the co $ _ 2 $ radiative cooling with a sufficiently large atomic oxygen abundance, and the gravity wave - induced cooling can alone result in up to 40 k colder temperature in the lower thermosphere. accounting for both mechanisms produce stronger cooling at high latitudes. however, radiative cooling effects peak above the mesopause, while gravity wave cooling rates continuously increase with height. although both mechanisms act simultaneously, these peculiarities could help to further quantify their relative contributions from future observations.
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arxiv:1504.05550
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let w be a compact simply connected triangulated manifold with boundary and $ k \ subset w $ be a subpolyhedron. we construct an algebraic model of the rational homotopy type of the complement $ w \ setminus k $ out of a model of the map of pairs $ ( k, k \ cap \ partial w ) \ to ( w, \ partial w ) $ under some high codimension hypothesis. we deduce the rational homotopy invariance of the configuration space of two points in a compact manifold with boundary under 2 - connectedness hypotheses. also, we exhibit nice explicits models of these configuration spaces for a large class of compact manifolds.
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arxiv:1505.04816
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this article is on the parametrization of the local langlands correspondence over local fields for non - quasi - split groups according to the philosophy of vogan. we show that a parametrization indexed by the basic part of the kottwitz set ( which is an extension of the set of pure inner twists ) implies a parametrization indexed by the full kottwitz set. on the galois side, we consider irreducible algebraic representations of the full centralizer group of the $ l $ - parameter ( i. e not a component group ). when $ f $ is a $ p $ - adic field, we discuss a generalization of the endoscopic character identity.
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arxiv:2211.13864
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the literature on adversarial attacks in computer vision typically focuses on pixel - level perturbations. these tend to be very difficult to interpret. recent work that manipulates the latent representations of image generators to create " feature - level " adversarial perturbations gives us an opportunity to explore perceptible, interpretable adversarial attacks. we make three contributions. first, we observe that feature - level attacks provide useful classes of inputs for studying representations in models. second, we show that these adversaries are uniquely versatile and highly robust. we demonstrate that they can be used to produce targeted, universal, disguised, physically - realizable, and black - box attacks at the imagenet scale. third, we show how these adversarial images can be used as a practical interpretability tool for identifying bugs in networks. we use these adversaries to make predictions about spurious associations between features and classes which we then test by designing " copy / paste " attacks in which one natural image is pasted into another to cause a targeted misclassification. our results suggest that feature - level attacks are a promising approach for rigorous interpretability research. they support the design of tools to better understand what a model has learned and diagnose brittle feature associations. code is available at https : / / github. com / thestephencasper / feature _ level _ adv
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arxiv:2110.03605
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we extend the analysis of black hole pair creation to include non - orientable instantons. we classify these instantons in terms of their fundamental symmetries and orientations. many of these instantons admit the pin structure which corresponds to the fermions actually observed in nature, and so the natural objection that these manifolds do not admit spin structure may not be relevant. furthermore, we analyse the thermodynamical properties of non - orientable black holes and find that in the non - extreme case, there are interesting modifications of the usual formulae for temperature and entropy.
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arxiv:gr-qc/9607079
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experience are considered to be more attractive to engineering employers. = = = = cooperative education programs = = = = cooperative education programs ( often referred to as ' co - ops ' ) are similar to internships insofar as they are employment opportunities offered to undergraduate students by engineering employers ; however, they are intended to take place concurrently with the students ' academic studies. co - ops are sometimes part - time roles that are ongoing throughout the academic semester, with the student expected to invest between 10 and 30 hours a week depending on the severity of their course load. some american universities, such as northeastern university and drexel university, incorporate co - ops into their students ' plan of study in the form of alternating semesters of full - time work and full - time classes ; these programs typically take an additional year to complete compared to most 4 - year undergraduate engineering programs in the us, even though northeastern currently has a 4 - year undergraduate program that integrates full - time co - ops with full - time studies. co - ops are considered to be a valuable form of professional development, and may be undertaken by students who are looking to bolster their resumes with hopes of securing better salary offers when looking to secure their first job. = = = = licensing = = = = after formal education, the engineer will often enter an internship or engineer in training status for approximately four years. to achieve engineering intern ( e. i. ) or engineer - in - training ( eit ) status, an individual must be the recipient of an engineering degree from an institution accredited by the engineering accreditation commission ( eac ) of the abet, formerly the accreditation board for engineering and technology, inc., as well as pass the fundamentals of engineering exam ( often abbreviated to the ' fe exam ' ). the fe exam is offered by the national council for examiners for engineering and surveying ( ncees ) for the following disciplines : mechanical engineering, civil engineering, industrial & systems engineering, chemical engineering, electrical & computer engineering, environmental engineering, or other disciplines ( also referred to as " general engineering " ). the fe exam is held at remote testing locations four times throughout the year and can be taken by college graduates as well as current college students. after successfully passing the fundamentals of engineering exam and receiving an abet - accredited engineering degree, an aspiring engineer may apply for engineer - in - training status with their state ' s licensing board. if granted, they may use the suffix e. i. t. to denote their status as an engineer - in -
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https://en.wikipedia.org/wiki/Engineering_education
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autism spectrum disorder ( asd ) is a neurodevelopmental condition characterized by challenges in social communication, repetitive behavior, and sensory processing. one important research area in asd is evaluating children ' s behavioral changes over time during treatment. the standard protocol with this objective is boscc, which involves dyadic interactions between a child and clinicians performing a pre - defined set of activities. a fundamental aspect of understanding children ' s behavior in these interactions is automatic speech understanding, particularly identifying who speaks and when. conventional approaches in this area heavily rely on speech samples recorded from a spectator perspective, and there is limited research on egocentric speech modeling. in this study, we design an experiment to perform speech sampling in boscc interviews from an egocentric perspective using wearable sensors and explore pre - training ego4d speech samples to enhance child - adult speaker classification in dyadic interactions. our findings highlight the potential of egocentric speech collection and pre - training to improve speaker classification accuracy.
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arxiv:2409.09340
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we consider a simple extension of the standard model by the addition of n real scalar gauge singlets $ \ vp $ that are candidates for dark matter. by collecting theoretical and experimental constraints we determine the space of allowed parameters of the model. the possibility of ameliorating the little hierarchy problem within the multi - singlet model is discussed. the spergel - steinhardt solution of the dark matter density cusp problem is revisited. it is shown that fitting the recent cresst - ii data for dark matter nucleus scattering implies that the standard higgs boson decays predominantly into pairs of dark matter scalars. it that case discovery of the higgs boson at lhc and tevatron is impossible. the most likely mass of the dark scalars is in the range 15 gev $ \ lsim \ mvp \ lsim $ 50 gev with $ br ( h \ to \ vp \ vp ) $ up to 96 %.
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arxiv:1112.2582
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graph - level anomaly detection aims to identify abnormal graphs that exhibit deviant structures and node attributes compared to the majority in a graph set. one primary challenge is to learn normal patterns manifested in both fine - grained and holistic views of graphs for identifying graphs that are abnormal in part or in whole. to tackle this challenge, we propose a novel approach called hierarchical memory networks ( himnet ), which learns hierarchical memory modules - - node and graph memory modules - - via a graph autoencoder network architecture. the node - level memory module is trained to model fine - grained, internal graph interactions among nodes for detecting locally abnormal graphs, while the graph - level memory module is dedicated to the learning of holistic normal patterns for detecting globally abnormal graphs. the two modules are jointly optimized to detect both locally - and globally - anomalous graphs. extensive empirical results on 16 real - world graph datasets from various domains show that i ) himnet significantly outperforms the state - of - art methods and ii ) it is robust to anomaly contamination. codes are available at : https : / / github. com / niuchx / himnet.
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arxiv:2307.00755
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we study reduced matrix models obtained by the dimensional reduction of n = 2 quiver chern - simons theories on s ^ 3 to zero dimension and show that if a reduced model is expanded around a particular multiple fuzzy sphere background, it becomes equivalent to the original theory on s ^ 3 in the large - n limit. this is regarded as a novel large - n reduction on a curved space s ^ 3. we perform the localization method to the reduced model and compute the free energy and the vacuum expectation value of a bps wilson loop operator. in the large - n limit, we find an exact agreement between these results and those in the original theory on s ^ 3.
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arxiv:1203.0559
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in this paper we consider the klein - gordon - maxwell system in the electrostatic case, assuming the fall - off large - distance requirement on the gauge potential. we are interested in proving the existence of finite energy ( and finite charge ) standing waves, having the phase corresponding to the mass coefficient in the klein - gordon lagrangian.
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arxiv:2009.00428
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covariate shift in regression problems and the associated distribution mismatch between training and test data is a commonly encountered phenomenon in machine learning. in this paper, we extend recent results on nonparametric convergence rates for i. i. d. data to markovian dependence structures. we demonstrate that under h \ " older smoothness assumptions on the regression function, convergence rates for the generalization risk of a nadaraya - watson kernel estimator are determined by the similarity between the invariant distributions associated to source and target markov chains. the similarity is explicitly captured in terms of a bandwidth - dependent similarity measure recently introduced in pathak, ma and wainwright [ icml, 2022 ]. precise convergence rates are derived for the particular cases of finite markov chains and spectral gap markov chains for which the similarity measure between their invariant distributions grows polynomially with decreasing bandwidth. for the latter, we extend the notion of a distribution transfer exponent from kpotufe and martinet [ ann. stat., 49 ( 6 ), 2021 ] to kernel transfer exponents of uniformly ergodic markov chains in order to generate a rich class of markov kernel pairs for which convergence guarantees for the covariate shift problem can be formulated.
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arxiv:2307.08517
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we study federated machine learning ( ml ) at the wireless edge, where power - and bandwidth - limited wireless devices with local datasets carry out distributed stochastic gradient descent ( dsgd ) with the help of a remote parameter server ( ps ). standard approaches assume separate computation and communication, where local gradient estimates are compressed and transmitted to the ps over orthogonal links. following this digital approach, we introduce d - dsgd, in which the wireless devices employ gradient quantization and error accumulation, and transmit their gradient estimates to the ps over a multiple access channel ( mac ). we then introduce a novel analog scheme, called a - dsgd, which exploits the additive nature of the wireless mac for over - the - air gradient computation, and provide convergence analysis for this approach. in a - dsgd, the devices first sparsify their gradient estimates, and then project them to a lower dimensional space imposed by the available channel bandwidth. these projections are sent directly over the mac without employing any digital code. numerical results show that a - dsgd converges faster than d - dsgd thanks to its more efficient use of the limited bandwidth and the natural alignment of the gradient estimates over the channel. the improvement is particularly compelling at low power and low bandwidth regimes. we also illustrate for a classification problem that, a - dsgd is more robust to bias in data distribution across devices, while d - dsgd significantly outperforms other digital schemes in the literature. we also observe that both d - dsgd and a - dsgd perform better by increasing the number of devices ( while keeping the total dataset size constant ), showing their ability in harnessing the computation power of edge devices.
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arxiv:1901.00844
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the ligo scientific, virgo and kagra collaborations recently released the third gravitational wave transient catalog or gwtc - 3, significantly expanding the number of gravitational wave ( gw ) signals. to address the - - still uncertain - - formation channels of the source compact binaries, their population properties must be characterized. the computational cost of the bayesian hierarchical methods employed thus far scales with the size of the event catalogs, and such methods have until recently assumed fixed functional forms for the source distribution. here we propose a fast and flexible method to reconstruct the population of ligo - - virgo merging black hole ( bh ) binaries without such assumptions. for sufficiently high event statistics and sufficiently low individual event measurement error ( relative to the scale of population features ) a kernel density estimator ( kde ) reconstruction of the event distribution will be accurate. we improve the accuracy and flexibility of kde for finite event statistics using an adaptive bandwidth kde ( awkde ). we apply awkde to publicly released parameter estimates for 44 significant ( 69 ) bh binary mergers in gwtc - 2 ( gwtc - 3 ), in combination with a fast polynomial fit of search sensitivity, to obtain a non - parametric estimate of the mass distribution, and compare to bayesian hierarchical methods. we also demonstrate a robust peak detection algorithm based on awkde and use it to calculate the significance of the apparent peak in the bh mass distribution around $ 35 \, m _ \ odot $. we find such a peak is very unlikely to have occurred if the true distribution is a featureless power - law ( significance of $ 3. 6 \ sigma $ for confident gwtc - 2 bbh events, $ 3. 0 \ sigma $ for confident gwtc - 3 bbh events ).
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arxiv:2112.12659
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this article summarizes the work presented at the workshop ' the power of faraday tomography : towards 3d mapping of cosmic magnetic fields ', held in miyazaki, japan, in spring 2018. we place the various oral and poster presentations given at the workshop in a broader perspective and present some highlight results from every presenter.
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arxiv:1910.08120
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an embedding of a unified dark sector model into string theory with the following features is proposed : the model - independent axion descending from the kalb - ramond 2 - form field is identified with the dark - matter field, and the real part of a k \ " ahler modulus field - - the ` ` radius ' ' of one of the extra spatial dimensions - - accounts for dark energy. the expectation value of the dilaton field is stabilized by a gaugino condensation mechanism. a dark - energy potential corresponding to a realistic low energy scale results from some gentle tuning of the stabilized expectation value of the dilaton. the resulting potential reproduces the one in a previous dark - sector model proposed by two of us.
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arxiv:2201.04668
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in zero - shot learning ( zsl ), generative methods synthesize class - related sample features based on predefined semantic prototypes. they advance the zsl performance by synthesizing unseen class sample features for better training the classifier. we observe that each class ' s predefined semantic prototype ( also referred to as semantic embedding or condition ) does not accurately match its real semantic prototype. so the synthesized visual sample features do not faithfully represent the real sample features, limiting the classifier training and existing zsl performance. in this paper, we formulate this mismatch phenomenon as the visual - semantic domain shift problem. we propose a dynamic semantic prototype evolving ( dsp ) method to align the empirically predefined semantic prototypes and the real prototypes for class - related feature synthesis. the alignment is learned by refining sample features and semantic prototypes in a unified framework and making the synthesized visual sample features approach real sample features. after alignment, synthesized sample features from unseen classes are closer to the real sample features and benefit dsp to improve existing generative zsl methods by 8. 5 \ %, 8. 0 \ %, and 9. 7 \ % on the standard cub, sun awa2 datasets, the significant performance improvement indicates that evolving semantic prototype explores a virgin field in zsl.
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arxiv:2306.06931
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the surrogate data method is widely applied as a data dependent technique to test observed time series against a barrage of hypotheses. however, often the hypotheses one is able to address are not those of greatest interest, particularly for system known to be nonlinear. in the review we focus on techniques which overcome this shortcoming. we summarize a number of recently developed surrogate data methods. while our review of surrogate methods is not exhaustive, we do focus on methods which may be applied to experimental, and potentially nonlinear, data. in each case, the hypothesis being tested is one of the interests to the experimental scientist.
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arxiv:nlin/0603004
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enabling ultra - reliable and low - latency communication services while providing massive connectivity is one of the major goals to be accomplished in future wireless communication networks. in this paper, we investigate the performance of a hybrid multi - access scheme in the finite blocklength ( fbl ) regime that combines the advantages of both non - orthogonal multiple access ( noma ) and time - division multiple access ( tdma ) schemes. two latency - sensitive application scenarios are studied, distinguished by whether the queuing behaviour has an influence on the transmission performance or not. in particular, for the latency - critical case with one - shot transmission, we aim at a certain physical - layer quality - of - service ( qos ) performance, namely the optimization of the reliability. and for the case in which queuing behaviour plays a role, we focus on the link - layer qos performance and provide a design that maximizes the effective capacity. for both designs, we leverage the characterizations in the fbl regime to provide the optimal framework by jointly allocating the blocklength and transmit power of each user. in particular, for the reliability - oriented design, the original problem is decomposed and the joint convexity of sub - problems is shown via a variable substitution method. for the effective - capacity - oriented design, we exploit the method of lagrange multipliers to formulate a solvable dual problem with strong duality to the original problem. via simulations, we validate our analytical results of convexity / concavity and show the advantage of our proposed approaches compared to other existing schemes.
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arxiv:2210.11272
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in this note, we show that the algebraicity of the fourier coefficients of half - integral weight modular forms can be determined by checking the algebraicity of the first few of them. we also give a necessary and sufficient condition for a half - integral weight modular form to be in kohnen ' s + - subspace by considering only finitely many terms.
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arxiv:1304.6586
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a series of fese0. 5te0. 5 bulk samples have been prepared through the high gas pressure and high - temperature synthesis ( hp - hts ) method to optimize the growth conditions, for the first time and investigated for their superconducting properties using structural, microstructure, transport, and magnetic measurements to reach the final conclusions. ex - situ and in - situ processes are used to prepare bulk samples under a range of growth pressures using ta - tube and without tatube. the parent compound synthesized by convenient synthesis method at ambient pressure ( csp ) exhibits a superconducting transition temperature of 14. 8 k. our data demonstrate that the prepared fese0. 5te0. 5 sealed in a ta - tube is of better quality than the samples without a ta - tube, and the optimum growth conditions ( 500 mpa, 600 { \ deg } c for 1 h ) are favourable for the development of the tetragonal fese0. 5te0. 5 phase. the optimum bulk fese0. 5te0. 5 depicts a higher transition temperature of 17. 3 k and a high critical current density of the order of > 10 ^ 4 a / cm ^ 2 at 0 t, which is improved over the entire magnetic field range and almost twice higher than the parent compound prepared through csp. our studies confirm that the high - pressure synthesis method is a highly efficient way to improve the superconducting transition, grain connectivity, sample density, and also pinning properties of a superconductor.
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arxiv:2308.01116
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electroweak ( ew ) corrections can be enhanced at high energies due to the soft or collinear radiation of virtual and real $ w $ and $ z $ bosons that result in sudakov - like corrections of the form $ \ alpha _ w ^ l \ log ^ n ( q ^ 2 / m _ { w, z } ^ 2 ) $, where $ \ alpha _ w = \ alpha / ( 4 \ pi \ sin ^ 2 \ theta _ w ) $ and $ n \ le 2l - 1 $. the inclusion of ew corrections in predictions for hadron colliders is therefore especially important when searching for signals of possible new physics in distributions probing the kinematic regime $ q ^ 2 \ gg m _ v ^ 2 $. next - to - leading order ( nlo ) ew corrections should also be taken into account when their size ( $ \ mathcal { o } ( \ alpha ) $ ) is comparable to that of qcd corrections at next - to - next - to - leading order ( nnlo ) ( $ \ mathcal { o } ( \ alpha _ s ^ 2 ) $ ). to this end we have implemented the nlo weak corrections to the neutral - current drell - yan process, top - quark pair production and di - jet production in the parton - level monte - carlo program mcfm. this enables a combined study with the corresponding qcd corrections at nlo and nnlo. we provide both the full nlo weak corrections and their sudakov approximation since the latter is often used for a fast evaluation of weak effects at high energies and can be extended to higher orders. with both the exact and approximate results at hand, the validity of the sudakov approximation can be readily quantified
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arxiv:1608.03356
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on applying a small bias force, non - equilibrium systems may respond in paradoxical ways such as with giant negative mobility ( gnm ) - - a large net drift opposite to the applied bias, or giant positive mobility ( gpm ) - - an anomalously large drift in the same direction as the applied bias. such behaviors have been extensively studied in idealized models of externally driven passive inertial particles. here, we consider a minimal model of a memory - driven active particle inspired from experiments with walking and superwalking droplets, whose equation of motion maps to the celebrated lorenz system. by adding a small bias force to this lorenz model for the active particle, we uncover a dynamical mechanism for simultaneous emergence of gnm and gpm in the parameter space. within the chaotic sea of the parameter space, a symmetric pair of coexisting asymmetric limit cycles separate and migrate under applied bias force, resulting in anomalous transport behaviors that are sensitive to the active particle ' s memory. our work highlights a general dynamical mechanism for the emergence of anomalous transport behaviors for active particles described by low - dimensional nonlinear models.
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arxiv:2408.00168
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channel routing is important in flood forecasting and watershed modeling. the general constant - parameter muskingum - cunge ( cpmc ) method is second - order accurate and easy to implement. with specific discretizations such that the temporal and spatial intervals maintain a unique relationship, the cpmc method can be third - order accurate. in this paper, we derive the average lateral inflow term in the second - and third - order accuracy cpmc method, and demonstrate that for spatially and temporally variable lateral inflow, the effect of lateral inflow on simulated discharge varies with spatial and temporal discretizations, the value and spatial and temporal variations of lateral inflow, wave celerity, and diffusion coefficient. comparison of the cpmc solution with the analytical solution shows that both the second - and third - order accuracy schemes are more accurate than the simplified method by which spatial derivatives of lateral inflow are ignored. for small time steps, the third - order accuracy cpmc method results in higher accuracy than the second - order scheme even when the third - order accuracy criterion is not fully met. for large time steps, the temporal and spatial discretization of the third - and second - order scheme becomes the same, but the third - order scheme yields higher accuracy than the second - order scheme because of the third - order accurate estimation of the lateral inflow term.
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arxiv:1802.04429
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a class of exact solutions is obtained for the li \ ' { e } nard type ordinary non - linear differential equation. as a first step in our study the second order li \ ' { e } nard type equation is transformed into a second kind abel type first order differential equation. with the use of an exact integrability condition for the abel equation ( the chiellini lemma ), the exact general solution of the abel equation can be obtained, thus leading to a class of exact solutions of the li \ ' { e } nard equation, expressed in a parametric form. we also extend the chiellini integrability condition to the case of the general abel equation. as an application of the integrability condition the exact solutions of some particular li \ ' { e } nard type equations, including a generalized van der pol type equation, are explicitly obtained.
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arxiv:1302.0836
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due to the extremely volatile nature of financial markets, it is commonly accepted that stock price prediction is a task full of challenge. however in order to make profits or understand the essence of equity market, numerous market participants or researchers try to forecast stock price using various statistical, econometric or even neural network models. in this work, we survey and compare the predictive power of five neural network models, namely, back propagation ( bp ) neural network, radial basis function ( rbf ) neural network, general regression neural network ( grnn ), support vector machine regression ( svmr ), least squares support vector machine regresssion ( ls - svmr ). we apply the five models to make price prediction of three individual stocks, namely, bank of china, vanke a and kweichou moutai. adopting mean square error and average absolute percentage error as criteria, we find bp neural network consistently and robustly outperforms the other four models.
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arxiv:1805.11317
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the cosmic microwave background temperature is a cornerstone astrophysical observable. its present value is tightly constrained, but its redshift dependence, which can now be determined until redshift $ z \ sim6. 34 $, is also an important probe of fundamental cosmology. we show that its constraining power is now comparable to that of other background cosmology probes, including type ia supernovae and hubble parameter measurements. we illustrate this with three models, each based on a different conceptual paradigm, which aim to explain the recent acceleration of the universe. we find that for parametric extension of $ \ lambda $ cdm the combination of temperature and cosmological data significantly improves constraints on the model parameters, while for alternative models without a $ \ lambda $ cdm limit this data combination rules them out.
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arxiv:2211.05377
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in this letter we report the singlet ground state structure of the full carotenoid peridinin by means of variational monte carlo ( vmc ) calculations. the vmc relaxed geometry has an average bond length alternation of 0. 1165 ( 10 ) { \ aa }, larger than the values obtained by dft ( pbe, b3lyp and cam - b3lyp ) and shorter than that calculated at the hartree - fock ( hf ) level. tddft and eom - ccsd calculations on a reduced peridinin model confirm the homo - lumo major contribution of the bu + - like ( s2 ) bright excited state. many body green ' s function theory ( mbgft ) calculations of the vertical excitation energy of the bu + - like state for the vmc structure ( vmc / mbgft ) provide excitation energy of 2. 62 ev, in agreement with experimental results in n - hexane ( 2. 72 ev ). the dependence of the excitation energy on the bond length alternation in the mbgft and tddft calculations with different functionals is discussed.
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arxiv:1404.4233
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the aim of this paper is to investigate the environment of gamma ray bursts ( grbs ) and the interstellar matter of their host galaxies. we use to this purpose high resolution spectroscopic observations of the afterglow of grb050922c, obtained with uves / vlt 3. 5 hours after the grb event. we found that, as for most high resolution spectra of grbs, the spectrum of the afterglow of grb050922c is complex. at least seven components contribute to the main absorption system at z = 2. 1992. the detection of lines of neutral elements like mgi and the detection of fine - structure levels of the ions feii, siii and cii allows us to separate components in the grb ism along the line of sight. moreover, in addition to the main system, we have analyzed the five intervening systems between z = 2. 077 and z = 1. 5664 identified along the grb line of sight. grb afterglow spectra are very complex, but full of information. this can be used to disentangle the contribution of the different parts of the grb host galaxy and to study their properties. our metallicity estimates agree with the scenario of grbs exploding in low metallicity galaxies
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arxiv:0811.0989
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it is believed that there may have been a large number of black holes formed in the very early universe. these would have quantised masses. a charged ` ` elementary black hole ' ' ( with the minimum possible mass ) can capture electrons, protons and other charged particles to form a ` ` black hole atom ' '. we find the spectrum of such an object with a view to laboratory and astronomical observation of them, and estimate the lifetime of the bound states. there is no limit to the charge of the black hole, which gives us the possibility of observing z > 137 bound states and transitions at the lower continuum. negatively charged black holes can capture protons. for z > 1, the orbiting protons will coalesce to form a nucleus ( after beta - decay of some protons to neutrons ), with a stability curve different to that of free nuclei. in this system there is also the distinct possibility of single quark capture. this leads to the formation of a coloured black hole that plays the role of an extremely heavy quark interacting strongly with the other two quarks. finally we consider atoms formed with much larger black holes.
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arxiv:gr-qc/0001022
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we study the effect of nuclear reaction on a thin, axisymmetric, differentially rotating, inviscid, steady accretion flow around a black hole from an analytical point of view. we find that for most of the reasonable disk parameters, when $ p - p $ - reaction, dissociation of deuterium and helium are taken into account, the transonic region of the disk continues to have the inner sonic point and if the temperature of the flow at the injection sonic point could be raised ( by say, some heating processes ) the flow would to pass through this inner sonic point. otherwise, the flow may be unstable. we use the sonic point analysis to study the solution. in the rest of the disk parameters the inner sonic point is absent altogether and the flow will definitely be unstable.
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arxiv:astro-ph/0103230
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learning from active human involvement enables the human subject to actively intervene and demonstrate to the ai agent during training. the interaction and corrective feedback from human brings safety and ai alignment to the learning process. in this work, we propose a new reward - free active human involvement method called proxy value propagation for policy optimization. our key insight is that a proxy value function can be designed to express human intents, wherein state - action pairs in the human demonstration are labeled with high values, while those agents ' actions that are intervened receive low values. through the td - learning framework, labeled values of demonstrated state - action pairs are further propagated to other unlabeled data generated from agents ' exploration. the proxy value function thus induces a policy that faithfully emulates human behaviors. human - in - the - loop experiments show the generality and efficiency of our method. with minimal modification to existing reinforcement learning algorithms, our method can learn to solve continuous and discrete control tasks with various human control devices, including the challenging task of driving in grand theft auto v. demo video and code are available at : https : / / metadriverse. github. io / pvp
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arxiv:2502.03369
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a worldsheet approach to the study of non - abelian d - particle dynamics is presented based on viewing matrix - valued d - brane coordinate fields as coupling constants of a deformed sigma - model which defines a logarithmic conformal field theory. the short - distance structure of spacetime is shown to be naturally captured by the zamolodchikov metric on the corresponding moduli space which encodes the geometry of the string interactions between d - particles. spacetime quantization is induced directly by the string genus expansion and leads to new forms of uncertainty relations which imply that general relativity at very short - distance scales is intrinsically described by a non - commutative geometry. the indeterminancies exhibit decoherence effects suggesting the natural incorporation of quantum gravity by short - distance d - particle probes. some potential experimental tests are briefly described.
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arxiv:hep-th/9811116
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for $ n \ leq d $, a family $ { \ cal f } = \ { c _ 0, c _ 1, \ ldots, c _ n \ } $ of compact convex sets in $ r ^ d $ is called an $ n $ - critical family provided any $ n $ members of $ { \ cal f } $ have a non - empty intersection, but $ \ bigcap _ { i = 0 } ^ n c _ i = \ varnothing $. if $ n = d $ then a lemma on the intersection of convex sets due to klee implies that the $ d + 1 $ members of the $ d $ - critical family enclose a ` hollow ' in $ r ^ d $, a bounded connected component of $ r ^ d \ setminus \ bigcup _ { i = 0 } ^ n c _ i. $ here we prove that the closure of the convex hull of a hollow in $ r ^ d $ is a $ d $ - simplex.
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arxiv:2105.14306
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i obtain the dynamics of the continuous time quantum walk on a $ d $ - dimensional lattice, with periodic boundary conditions, as an appropriate limit of the dynamics of the discrete time quantum walk on the same lattice. this extends the main result of arxiv : quant - ph / 0606050 which proved this limit for the infinite line. by highlighting the main features of the limiting procedure, i then extend it to general graphs. for a given discrete time quantum walk on a general graph, i single out the type of continuous dynamics ( hamiltonians ) that can be obtained as a limit of the discrete time dynamics.
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arxiv:0902.3496
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recently, one has seen a surge of interest in developing such methods including ones for learning such representations for ( undirected ) graphs ( while preserving important properties ). however, most of the work to date on embedding graphs has targeted undirected networks and very little has focused on the thorny issue of embedding directed networks. in this paper, we instead propose to solve the directed graph embedding problem via a two - stage approach : in the first stage, the graph is symmetrized in one of several possible ways, and in the second stage, the so - obtained symmetrized graph is embedded using any state - of - the - art ( undirected ) graph embedding algorithm. note that it is not the objective of this paper to propose a new ( undirected ) graph embedding algorithm or discuss the strengths and weaknesses of existing ones ; all we are saying is that whichever be the suitable graph embedding algorithm, it will fit in the above proposed symmetrization framework.
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arxiv:1811.12164
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in this paper, we tackle a problem of predicting phenotypes from structural connectomes. we propose that normalized laplacian spectra can capture structural properties of brain networks, and hence graph spectral distributions are useful for a task of connectome - based classification. we introduce a kernel that is based on earth mover ' s distance ( emd ) between spectral distributions of brain networks. we access performance of an svm classifier with the proposed kernel for a task of classification of autism spectrum disorder versus typical development based on a publicly available dataset. classification quality ( area under the roc - curve ) obtained with the emd - based kernel on spectral distributions is 0. 71, which is higher than that based on simpler graph embedding methods.
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arxiv:1611.08812
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an instanton method is proposed to investigate the quantum tunneling between two weakly - linked bose - einstein condensates confined in double - well potential traps. we point out some intrinsic pathologies in the earlier treatments of other authors and make an effort to go beyond these very simple zero order models. the tunneling amplitude may be calculated in the thomas - fermi approximation and beyond it ; we find it depends on the number of the trapped atoms, through the chemical potential. some suggestions are given for the observation of the josephson oscillation and the mqst.
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arxiv:cond-mat/0110054
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transcription factors ( tfs ) are macromolecules that bind to \ textit { cis } - regulatory specific sub - regions of dna promoters and initiate transcription. finding the exact location of these binding sites ( aka motifs ) is important in a variety of domains such as drug design and development. to address this need, several \ textit { in vivo } and \ textit { in vitro } techniques have been developed so far that try to characterize and predict the binding specificity of a protein to different dna loci. the major problem with these techniques is that they are not accurate enough in prediction of the binding affinity and characterization of the corresponding motifs. as a result, downstream analysis is required to uncover the locations where proteins of interest bind. here, we propose deeperbind, a long short term recurrent convolutional network for prediction of protein binding specificities with respect to dna probes. deeperbind can model the positional dynamics of probe sequences and hence reckons with the contributions made by individual sub - regions in dna sequences, in an effective way. moreover, it can be trained and tested on datasets containing varying - length sequences. we apply our pipeline to the datasets derived from protein binding microarrays ( pbms ), an in - vitro high - throughput technology for quantification of protein - dna binding preferences, and present promising results. to the best of our knowledge, this is the most accurate pipeline that can predict binding specificities of dna sequences from the data produced by high - throughput technologies through utilization of the power of deep learning for feature generation and positional dynamics modeling.
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arxiv:1611.05777
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we present a combination of elastic neutron scattering measurements in zero and 14. 5 t and magnetization measurements in zero and 14 t on under - doped superconducting ba $ _ { 1 - x } $ k $ _ { x } $ fe $ _ { 2 } $ as $ _ { 2 } $ x = 0. 17, and the same measurements in zero field on a non - superconducting crystal with x = 0. 09. the data suggest that the under - doped materials may not be electronic phase separated but rather have slightly inhomogeneous potassium doping. the temperature dependence of the magnetic order parameter ( op ) below the transition of the sample with x = 0. 09 is more gradual than that for the case of the un - doped bafe $ _ { 2 } $ as $ _ { 2 } $, suggesting that this doping may be in the vicinity of a tricritical point. we advance therefore the hypothesis that the tricritical point is a common feature of all superconducting 122s. for the x = 0. 17 sample, while t $ _ { c } $ is suppressed from $ \ approx $ 17 k to $ \ approx $ 8 k by a magnetic field of 14 t, the intensity of the magnetic bragg peaks ( 1 0 3 ) at 1. 2 k is enhanced by 10 $ % $ showing competition of superconductivity ( sc ) and antiferromagnetism ( afm ). the intensity of the magnetic bragg peaks ( 1 0 3 ) in the ( t $ _ { c } $, t $ _ { n } $ ) temperature interval remain practically unchanged in 14. 5 t within a 10 $ % $ statistical error. the present results are discussed in the context of the existing literature.
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arxiv:1111.3329
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we present a summary of our recent work on the vertical distribution of the resolved stellar populations in six low mass, edge - on, spiral galaxies observed with the hubble space telescope advanced camera for surveys ( hst / acs ). in each galaxy we find evidence for an extraplanar stellar component extending up to 15 scale heights ( ~ 3. 5 kpc ) above the plane. we analyze the vertical distribution as a function of stellar age by tracking changes in the color - magnitude diagram. the young stellar component ( < 10 ^ 8 yrs ) is found to have a scale height larger than the young component in the milky way, suggesting that stars in these low mass galaxies form in a thicker disk. we also find that the scale height of a stellar population increases with age, with young main sequence stars, intermediate age asymptotic giant branch stars, and old red giant branch stars having succesively larger scale heights in each galaxy. the color distributions of the red giant branch ( rgb ) stars well above the midplane indicate that the extended stellar components we see are moderately metal - poor, with peak metallicities of [ fe / h ] ~ - 1 and with little or no metallicity gradient with height. the lack of metallicity gradient can be explained if a majority of extraplanar rgb stars were formed at early times and are not dominated by a younger heated population. our observations suggest that, like the milky way, low mass disk galaxies also have multiple stellar components. we examine our results in light of disk heating and merger scenarios and conclude that both mechanisms likely played a role in forming the disks of our sample galaxies.
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arxiv:astro-ph/0506429
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in this note we present a collection of attempts of some researchers to prove or disprove whether the zeraoulia sequences convergent. even nowdays convergence of zeraoulia sequences still open.
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arxiv:2201.00643
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with the accurate measurements of $ \ chi _ { cj } ( j = 0, 1, 2 ) $ charmonium decays, we explore $ \ chi _ { cj } \ to \ mathcal { b } _ { 8 } \ bar { \ mathcal { b } } _ { 8 } $ and $ \ mathcal { b } _ { 10 } \ bar { \ mathcal { b } } _ { 10 } $ decays based on the su ( 3 ) flavor symmetry model, where $ \ mathcal { b } _ { 8 } $ and $ \ mathcal { b } _ { 10 } $ are light octet and decuplet baryons, respectively. the decay amplitude relations are determined by an effective interaction hamiltonian. then using experimental data and the amplitude relations of $ \ chi _ { cj } \ to \ mathcal { b } _ { 8 } \ bar { \ mathcal { b } } _ { 8 } $, $ \ mathcal { b } _ { 10 } \ bar { \ mathcal { b } } _ { 10 } $ decays, relative nonperturbative coefficients are constrained, and the branching ratios of unmeasured $ \ chi _ { cj } \ to \ mathcal { b } _ { 8 } \ bar { \ mathcal { b } } _ { 8 }, \ mathcal { b } _ { 10 } \ bar { \ mathcal { b } } _ { 10 } $, for examples, $ \ chi _ { cj } \ to n \ bar { n } $ and $ \ chi _ { cj } \ to \ lambda \ bar { \ sigma } ^ { 0 } + \ bar { \ lambda } \ sigma ^ { 0 } $ channels, are predicted. moreover, we discuss the case of adding a mixing angle between $ \ lambda $ and $ \ sigma ^ { 0 } $, which is determined by the quark mass differences. our results provide valuable insights that will aid in advancing our understanding of the mechanisms and characteristics of $ \ chi _ { cj } $ decays.
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arxiv:2405.11879
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the lack of x - ray pulsars with spin periods > 12 s raises the question of where the population of evolved high magnetic field neutron stars has gone. unlike canonical radio pulsars, x - ray pulsars are not subject to physical limits to the emission mechanism nor observational biases against the detection of sources with longer periods. here we show that a highly resistive layer in the innermost part of the crust of neutron stars naturally limits the spin period to a maximum value of about 10 - 20 s. this highly resistive layer is expected if the inner crust is amorphous and heterogeneous in nuclear charge, possibly due to the existence of a nuclear pasta phase. our findings suggest that the maximum period of isolated x - ray pulsars can be the first observational evidence of an amorphous inner crust, which properties can be further constrained by future x - ray timing missions combined with more detailed models.
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arxiv:1304.6546
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since 2015, with the restart of the lhc for its second run of data taking, the lhcb experiment has been empowered with a dedicated computing model to select and analyse calibration samples to measure the performance of the particle identification ( pid ) detectors and algorithms. the novel technique was developed within the framework of the innovative trigger model of the lhcb experiment, which relies on online event reconstruction for most of the datasets, reserving offline reconstruction to special physics cases. the strategy to select and process the calibration samples, which includes a dedicated data - processing scheme combining online and offline reconstruction, is discussed. the use of the calibration samples to measure the detector pid performance, and the efficiency of pid requirements across a large range of decay channels, is described. applications of the calibration samples in data - quality monitoring and validation procedures are also detailed.
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arxiv:1803.00824
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we study killing vector fields in asymptotically flat space - times. we prove the following result, implicitly assumed in the uniqueness theory of stationary black holes. if the conditions of the rigidity part of the positive energy theorem are met, then in such space - times there are no asymptotically null killing vector fields except if the initial data set can be embedded in minkowski space - time. we also give a proof of the non - existence of non - singular ( in an appropriate sense ) asymptotically flat space - times which satisfy an energy condition and which have a null adm four - momentum, under conditions weaker than previously considered.
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arxiv:gr-qc/9510015
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a search for heavy resonances decaying into a pair of $ z $ bosons leading to $ \ ell ^ + \ ell ^ - \ ell ^ + \ ell ^ - $ and $ \ ell ^ + \ ell ^ - \ nu \ bar \ nu $ final states, where $ \ ell $ stands for either an electron or a muon, is presented. the search uses proton proton collision data at a centre - of - mass energy of 13 tev corresponding to an integrated luminosity of 36. 1 fb $ ^ { - 1 } $ collected with the atlas detector during 2015 and 2016 at the large hadron collider. different mass ranges for the hypothetical resonances are considered, depending on the final state and model. the different ranges span between 200 gev and 2000 gev. the results are interpreted as upper limits on the production cross section of a spin 0 or spin 2 resonance. the upper limits for the spin 0 resonance are translated to exclusion contours in the context of type i and type ii two - higgs - doublet models, while those for the spin 2 resonance are used to constrain the randall sundrum model with an extra dimension giving rise to spin 2 graviton excitations.
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arxiv:1712.06386
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it is proved that, according to classical mechanics and electrodynamics, the trajectory of the center of mass of a neutral system of electrical charges can be deflected by an inhomogeneous magnetic field, even if its internal angular momentum is zero. this challenges the common view about the function of the stern - gerlach apparatus, as resolving the eigen - states of an intrinsic angular momentum. doubts are cast also on the supposed failure of schrodinger ' s theory to explain the properties of atoms in presence of magnetic fields without introducing spin variables.
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arxiv:quant-ph/0305137
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in this paper we calculate the casimir - polder force density ( force per unit area acting on the elements of the surface ) on a metallic plate placed in front of a neutral atom. to obtain the force density we use the quantum operator associated to the electromagnetic stress tensor. we explicitly show that the integral of this force density over the plate reproduces the total force acting on the plate. this result shows that, although the force is obtained as a sum of surface element - atom contributions, the stress - tensor method includes also nonadditive components of casimir - polder forces in the evaluation of the force acting on a macroscopic object.
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arxiv:quant-ph/0611152
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a bipartite subspace $ s $ is called strongly positive - partial - transpose - unextendible ( ppt - unextendible ) if for every positive integer $ k $, there is no ppt operator supporting on the orthogonal complement of $ s ^ { \ otimes k } $. we show that a subspace is strongly ppt - unextendible if it contains a ppt - definite operator ( a positive semidefinite operator whose partial transpose is positive definite ). based on these, we are able to propose a simple criterion for verifying whether a set of bipartite orthogonal quantum states is indistinguishable by ppt operations in the many copy scenario. utilizing this criterion, we further point out that any entangled pure state and its orthogonal complement cannot be distinguished by ppt operations in the many copy scenario. on the other hand, we investigate that the minimum dimension of strongly ppt - unextendible subspaces in an $ m \ otimes n $ system is $ m + n - 1 $, which involves a generalization of the result that non - positive - partial - transpose ( npt ) subspaces can be as large as any entangled subspace [ n. johnston, phys. rev. a 87 : 064302 ( 2013 ) ].
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arxiv:1702.00231
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a generic f - theory compactification containing many d3 branes develops multiple brane throats. the interaction of observers residing inside different throats involves tunneling suppression and, as a result, is very weak. this suggests a new mechanism for generating small numbers in nature. one application is to the hierarchy problem : large supersymmetry breaking near the unification scale inside a shallow throat causes tev - scale susy - breaking inside the standard - model throat. another application, inspired by nuclear - decay, is in designing naturally long - lived particles : a cold dark matter particle residing near the standard model brane decays to an approximate cft - state of a longer throat within a hubble time. this suggests that most of the mass of the universe today could consist of cft - matter and may soften structure formation at sub - galactic scales. the tunneling calculation demonstrates that the coupling between two throats is dominated by higher dimensional modes and consequently is much larger than a naive application of holography might suggest.
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arxiv:hep-th/0106128
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in higher organisms, all cells share the same genome, but every cell expresses only a limited and specific set of genes that defines the cell type. during cell division, not only the genome, but also the cell type is inherited by the daughter cells. this intriguing phenomenon is achieved by a variety of processes that have been collectively termed epigenetics : the stable and inheritable changes in gene expression patterns. this article reviews the extremely rich and exquisitely multi - scale physical mechanisms that govern the biological processes behind the initiation, spreading and inheritance of epigenetic states. these include not only the changes in the molecular properties associated with the chemical modifications of dna and histone proteins, such as methylation and acetylation, but also less conventional ones, such as the physics that governs the three - dimensional organization of the genome in cell nuclei. strikingly, to achieve stability and heritability of epigenetic states, cells take advantage of many different physical principles, such as the universal behavior of polymers and copolymers, the general features of non - equilibrium dynamical systems, and the electrostatic and mechanical properties related to chemical modifications of dna and histones. by putting the complex biological literature under this new light, the emerging picture is that a limited set of general physical rules play a key role in initiating, shaping and transmitting this crucial " epigenetic landscape ". this new perspective not only allows to rationalize the normal cellular functions, but also helps to understand the emergence of pathological states, in which the epigenetic landscape becomes dysfunctional.
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arxiv:1509.04145
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in gas dynamics, the connection between the continuum physics model offered by the navier - stokes equations and the heat equation and the molecular model offered by the kinetic theory of gases has been understood for some time, especially through the work of chapman and enskog, but it has never been established rigorously. this paper established a precise bridge between this two models for a simple linear boltzman - like equation. specifically a special class of solutions, the grossly determined solutions, of this kinetic model are shown to exist and satisfy closed form balance equations representing a class of continuum model solutions.
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arxiv:1607.08282
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while the separation ( the minimal nonzero distance ) between roots of a polynomial is a classical topic, its absolute counterpart ( the minimal nonzero distance between their absolute values ) does not seem to have been studied much. we present the general context and give tight bounds for the case of real roots.
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arxiv:1606.01131
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within the framework of v - t theory of monatomic liquid dynamics, an exact equation is derived for a general equilibrium time correlation function. the purely vibrational contribution to such a function expresses the system ' s motion in one extended harmonic random valley. this contribution is analytically tractable and has no adjustable parameters. while this contribution alone dominates the thermodynamic properties, both vibrations and transits will make important contributions to time correlation functions. by way of example, the v - t formulation of time correlation functions is applied to the dynamic structure factor s ( q, w ). the vibrational contribution alone is shown to be in near perfect agreement with low - temperature molecular dynamics simulations, and a model simulating the transit contribution with three adjustable parameters achieves equally good agreement with molecular dynamics results in the liquid regime. the theory indicates that transits will broaden without shifting the rayleigh and brillouin peaks in s ( q, w ), and this behavior is confirmed by the md calculations. we find the vibrational contribution alone gives the location and much of the width of the liquid - state brillouin peak. we also discuss this approach to liquid dynamics compared with potential energy landscape formalisms and mode coupling theory, drawing attention to the distinctive features of our approach and to some potential energy landscape results which support our picture of the liquid state.
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arxiv:cond-mat/0511748
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the evolution of deformation from plasticity to localization to damage is investigated in ferritic - pearlitic steel through nanometer - resolution microstructure - correlated sem - dic ( u - dic ) strain mapping, enabled through highly accurate microstructure - to - strain alignment. we reveal the key plasticity mechanisms in ferrite and pearlite as well as their evolution into localization and damage and their relation to the microstructural arrangement. notably, two contrasting mechanisms were identified that control whether damage initiation in pearlite occurs and, through connection of localization hotspots in ferrite grains, potentially results in macroscale fracture : ( i ) cracking of pearlite bridges with relatively clean lamellar structure by brittle fracture of cementite lamellae due to build - up of strain concentrations in nearby ferrite, versus ( ii ) large plasticity without damage in pearlite bridges with a more " open ", chaotic pearlite morphology, which enables plastic percolation paths in the interlamellar ferrite channels. based on these insights, recommendations for damage resistant ferritic - pearlitic steels are proposed.
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arxiv:2104.11817
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in the present paper we consider the extended scalar - tensor - gauss - bonnet gravity with a massive scalar field. we prove numerically the existence of gauss - bonnet black holes for three different forms of the coupling function including the case of spontaneous scalarization. we have performed a systematic study of the black hole characteristics such as the area of the horizon, the entropy and the temperature for these coupling functions and compared them to the schwarzschild solutions. the introduction of scalar field mass leads to a suppression of the scalar field and the increase of this mass brings the black holes closer to the schwarzschild case. for linear and exponential coupling, a nonzero scalar field mass expands the domain of existence of black holes solutions. larger deviations from the gr case are observed only for small masses and these differences decrease with the increase of the scalar field mass. in the case of a coupling function which leads to scalarization the scalar field mass has a significant influence on the bifurcation points where the scalarized black holes branch out of the schwarzschild solution. the largest deviation from the case with a massless scalar field are observed for black hole masses close to the bifurcation point.
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arxiv:1903.08119
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bayesian graphical modeling provides an appealing way to obtain uncertainty estimates when inferring network structures, and much recent progress has been made for gaussian models. these models have been used extensively in applications to gene expression data, even in cases where there appears to be significant deviations from the gaussian model. for more robust inferences, it is natural to consider extensions to t - distribution models. we argue that the classical multivariate t - distribution, defined using a single latent gamma random variable to rescale a gaussian random vector, is of little use in highly multivariate settings, and propose other, more flexible t - distributions. using an independent gamma - divisor for each component of the random vector defines what we term the alternative t - distribution. the associated model allows one to extract information from highly multivariate data even when most experiments contain outliers for some of their measurements. however, the use of this alternative model comes at increased computational cost and imposes constraints on the achievable correlation structures, raising the need for a compromise between the classical and alternative models. to this end we propose the use of dirichlet processes for adaptive clustering of the latent gamma - scalars, each of which may then divide a group of latent gaussian variables. dirichlet processes are commonly used to cluster independent observations ; here they are used instead to cluster the dependent components of a single observation. the resulting dirichlet t - distribution interpolates naturally between the two extreme cases of the classical and alternative t - distributions and combines more appealing modeling of the multivariate dependence structure with favorable computational properties.
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arxiv:1207.1221
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we have developed a watt - level random laser at 532 nm. the laser is based on a 1064 nm random distributed ytterbium - gain assisted fiber laser seed with a 0. 35 nm line - width 900mw polarized output power. a study for the optimal length of the random distributed mirror was carried out. an ytterbium - doped fiber master oscillator power amplifier architecture is used to amplify the random seeder laser without additional spectral broadening up to 20 w. by using a periodically poled lithium niobate ( ppln ) crystal in a single pass configuration we generate in excess of 1 w random laser at 532 nm by second harmonic generation with an efficiency of 9 %. the green random laser exhibits an instability < 1 %, optical signal to noise ratio > 70 db, 0. 1 nm linewidth and excellent beam quality.
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arxiv:1903.12439
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from each point of a poisson point process start growing a balloon at rate 1. when two balloons touch, they pop and disappear. is every point contained in balloons infinitely often or not? we answer this for the euclidean space, the hyperbolic plane and regular trees. the result for the euclidean space relies on a novel 0 - 1 law for stationary processes. towards establishing the results for the hyperbolic plane and regular trees, we prove an upper bound on the density of any well - separated set in a regular tree which is a factor of an i. i. d. process.
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arxiv:2103.06847
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the dynamics of many epidemic compartmental models for infectious diseases that spread in a single host population present a second - order phase transition. this transition occurs as a function of the infectivity parameter, from the absence of infected individuals to an endemic state. here, we study this transition, from the perspective of dynamical systems, for a discrete - time compartmental epidemic model known as microscopic markov chain approach, whose applicability for forecasting future scenarios of epidemic spreading has been proved very useful during the covid - 19 pandemic. we show that there is an endemic state which is stable and a global attractor and that its existence is a consequence of a transcritical bifurcation. this mathematical analysis grounds the results of the model in practical applications.
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arxiv:2210.17156
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causal models defined in terms of a collection of equations, as defined by pearl, are axiomatized here. axiomatizations are provided for three successively more general classes of causal models : ( 1 ) the class of recursive theories ( those without feedback ), ( 2 ) the class of theories where the solutions to the equations are unique, ( 3 ) arbitrary theories ( where the equations may not have solutions and, if they do, they are not necessarily unique ). it is shown that to reason about causality in the most general third class, we must extend the language used by galles and pearl. in addition, the complexity of the decision procedures is examined for all the languages and classes of models considered.
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arxiv:1408.1482
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we use gaia data release 2 to identify 13, 928 white dwarfs within 100 pc of the sun. the exquisite astrometry from gaia reveals for the first time a bifurcation in the observed white dwarf sequence in both gaia and the sloan digital sky survey ( sdss ) passbands. the latter is easily explained by a helium atmosphere white dwarf fraction of 36 %. however, the bifurcation in the gaia colour - magnitude diagram depends on both the atmospheric composition and the mass distribution. we simulate theoretical colour - magnitude diagrams for single and binary white dwarfs using a population synthesis approach and demonstrate that there is a significant contribution from relatively massive white dwarfs that likely formed through mergers. these include white dwarf remnants of main - sequence ( blue stragglers ) and post - main sequence mergers. the mass distribution of the sdss subsample, including the spectroscopically confirmed white dwarfs, also shows this massive bump. this is the first direct detection of such a population in a volume - limited sample.
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arxiv:1805.01227
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deep reading models for question - answering have demonstrated promising performance over the last couple of years. however current systems tend to learn how to cleverly extract a span of the source document, based on its similarity with the question, instead of seeking for the appropriate answer. indeed, a reading machine should be able to detect relevant passages in a document regarding a question, but more importantly, it should be able to reason over the important pieces of the document in order to produce an answer when it is required. to motivate this purpose, we present reviewqa, a question - answering dataset based on hotel reviews. the questions of this dataset are linked to a set of relational understanding competencies that we expect a model to master. indeed, each question comes with an associated type that characterizes the required competency. with this framework, it is possible to benchmark the main families of models and to get an overview of what are the strengths and the weaknesses of a given model on the set of tasks evaluated in this dataset. our corpus contains more than 500. 000 questions in natural language over 100. 000 hotel reviews. our setup is projective, the answer of a question does not need to be extracted from a document, like in most of the recent datasets, but selected among a set of candidates that contains all the possible answers to the questions of the dataset. finally, we present several baselines over this dataset.
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arxiv:1810.12196
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statistical methods for functional data are of interest for many applications. in this paper, we prove a central limit theorem for random variables taking their values in a hilbert space. the random variables are assumed to be weakly dependent in the sense of near epoch dependence, where the underlying process fulfills some mixing conditions. as parametric inference in an infinite dimensional space is difficult, we show that the nonoverlapping block bootstrap is consistent. furthermore, we show how these results can be used for degenerate von mises - statistics.
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arxiv:1312.3870
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