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we prove that the generic maximal independent family obtained by iteratively forcing with the mathias forcing relative to diagonalization filters is densely maximal. moreover, by choosing the filters with some care one can ensure the family is selective and hence forcing indestructible in a strong sense. using this we prove that under $ \ mathfrak { p } = 2 ^ { \ aleph _ 0 } $ there are selective independent families and also we show how to add selective independent families of any desired size. | arxiv:2306.09809 |
assuming fiorenza - sati - schreiber ' s hypothesis h, on the charge quantization of m - theory ' s $ c $ - field, the topological sectors of the resulting $ string ^ { c _ 2 } ( 4 ) $ - valued higher gauge theory on a heterotic m5 - brane are classified by homotopy classes of maps from the worldvolume $ \ sigma _ { m5 } $ to $ bstring ^ { c _ 2 } ( 4 ) $. this note calculates the sectors in a number of examples of m5 - brane topology, including examples considered in the 3d - 3d correspondence, the emergence of skyrmions from higher - dimensional instantons and witten ' s analysis of the s - duality of 4d yang - mills theory. | arxiv:2003.09832 |
the polarizations of the y ( 1s ), y ( 2s ), and y ( 3s ) mesons are measured in proton - proton collisions at sqrt ( s ) = 7 tev, using a data sample of y ( ns ) to oppositely charged muon pair decays collected by the cms experiment, corresponding to an integrated luminosity of 4. 9 inverse femtobarns. the dimuon decay angular distributions are analyzed in three different polarization frames. the polarization parameters lambda [ theta ], lambda [ phi ], and lambda [ theta, phi ], as well as the frame - invariant quantity lambda - tilde, are presented as a function of the y ( ns ) transverse momentum between 10 and 50 gev, in the rapidity ranges abs ( y ) < 0. 6 and 0. 6 < abs ( y ) < 1. 2. no evidence of large transverse or longitudinal polarizations has been seen in the explored kinematic region. | arxiv:1209.2922 |
turbulent fragmentation determines where and when protostellar cores form, and how they contract and grow in mass from the surrounding cloud material. this process is investigated, using numerical models of self - gravitating molecular cloud dynamics. molecular cloud regions without turbulent driving sources, or where turbulence is driven on large scales, exhibit rapid and efficient star formation in a clustered mode, whereas interstellar turbulence that carries most energy on small scales results in isolated star formation with low efficiency. the clump mass spectrum of shock - generated density fluctuations in pure hydrodynamic, supersonic turbulence is not well fit by a power law, and it is too steep at the high - mass end to be in agreement with the observational data. when gravity is included in the turbulence models, local collapse occurs, and the spectrum extends towards larger masses as clumps merge together, a power - law description dn / dm ~ m ^ nu becomes possible with slope nu < - 2. in the case of pure gravitational contraction, i. e. in regions without turbulent support, the clump mass spectrum is shallower with nu = - 3 / 2. the mass spectrum of protostellar cores in regions without turbulent support and where turbulence is replenished on large - scales, however, is well described by a log - normal or by multiple power laws, similar to the stellar imf at low and intermediate masses. in the case of small - scale turbulence, the core mass spectrum is too flat compared to the imf for all masses. | arxiv:astro-ph/0104127 |
large language models ( llms ) excel in abstractive summarization tasks, delivering fluent and pertinent summaries. recent advancements have extended their capabilities to handle long - input contexts, exceeding 100k tokens. however, in question answering, language models exhibit uneven utilization of their input context. they tend to favor the initial and final segments, resulting in a u - shaped performance pattern concerning where the answer is located within the input. this bias raises concerns, particularly in summarization where crucial content may be dispersed throughout the source document ( s ). besides, in summarization, mapping facts from the source to the summary is not trivial as salient content is usually re - phrased. in this paper, we conduct the first comprehensive study on context utilization and position bias in summarization. our analysis encompasses 6 llms, 10 datasets, and 5 evaluation metrics. we introduce a new evaluation benchmark called middlesum on the which we benchmark two alternative inference methods to alleviate position bias : hierarchical summarization and incremental summarization. our code and data can be found here : https : / / github. com / ntunlp / middlesum. | arxiv:2310.10570 |
this paper concerns a relatively new combinatorial structure called staircase tableaux. they were introduced in the context of the asymmetric exclusion process and askey - - wilson polynomials, however, their purely combinatorial properties have gained considerable interest in the past few years. in this paper we further study combinatorial properties of staircase tableaux. we consider a general model of staircase tableaux in which symbols that appear in staircase tableaux may have arbitrary positive weights. under this general model we derive a number of results. some of our results concern the limiting laws for the number of appearances of symbols in a random staircase tableaux. they generalize and subsume earlier results that were obtained for specific values of the weights. one advantage of our generality is that we may let the weights approach extreme values of zero or infinity which covers further special cases appearing earlier in the literature. furthermore, our generality allows us to analyze the structure of random staircase tableaux and we obtain several results in this direction. one of the tools we use are generating functions of the parameters of interests. this leads us to a two - - parameter family of polynomials and we study this family as well. specific values of the parameters include number of special cases analyzed earlier in the literature. all of them are generalizations of the classical eulerian polynomials. we also briefly discuss the relation of staircase tableaux to the asymmetric exclusion process, to other recently introduced types of tableaux, and to an urn model studied by a number of researchers, including philippe flajolet. | arxiv:1212.5498 |
we propose a research strategy for creating and deploying prescriptive recommendations for spreadsheet practice. empirical data on usage can be used to create a taxonomy of spreadsheet classes. within each class, existing practices and ideal practices can he combined into proposed best practices for deployment. as a first step we propose a scoping survey to gather non - anecdotal data on spreadsheet usage. the scoping survey will interview people who develop spreadsheets. we will investigate the determinants of spreadsheet importance, identify current industry practices, and document existing standards for creation and use of spreadsheets. the survey will provide insight into user attributes, spreadsheet importance, and current practices. results will be valuable in themselves, and will guide future empirical research. | arxiv:0807.3184 |
two - dimensional ( 2d ) transition metal dichalcogenides ( tmds ) have a range of unique physics properties and could be used in the development of electronics, photonics, spintronics and quantum computing devices. the mechanical exfoliation technique of micro - size tmd flakes has attracted particular interest due to its simplicity and cost effectiveness. however, for most applications, large area and high quality films are preferred. furthermore, when the thickness of crystalline films is down to the 2d limit ( monolayer ), exotic properties can be expected due to the quantum confinement and symmetry breaking. in this paper, we have successfully prepared macro - size atomically flat monolayer nbse2 films on bilayer graphene terminated surface of 6h - sic ( 0001 ) substrates by molecular beam epitaxy ( mbe ) method. the films exhibit an onset superconducting critical transition temperature above 6 k, 2 times higher than that of mechanical exfoliated nbse2 flakes. simultaneously, the transport measurements at high magnetic fields reveal that the parallel characteristic field bc / / is at least 4. 5 times higher than the paramagnetic limiting field, consistent with zeeman - protected ising superconductivity mechanism. besides, by ultralow temperature electrical transport measurements, the monolayer nbse2 film shows the signature of quantum griffiths singularity when approaching the zero - temperature quantum critical point. | arxiv:1707.05473 |
) = 1 } ; and every other measure with these properties extends the lebesgue measure. circular angle measure is invariant under rotation, and hyperbolic angle measure is invariant under squeeze mapping. the haar measure for a locally compact topological group is a generalization of the lebesgue measure ( and also of counting measure and circular angle measure ) and has similar uniqueness properties. every ( pseudo ) riemannian manifold ( m, g ) { \ displaystyle ( m, g ) } has a canonical measure μ g { \ displaystyle \ mu _ { g } } that in local coordinates x 1, …, x n { \ displaystyle x _ { 1 }, \ ldots, x _ { n } } looks like | det g | d n x { \ displaystyle { \ sqrt { \ left | \ det g \ right | } } d ^ { n } x } where d n x { \ displaystyle d ^ { n } x } is the usual lebesgue measure. the hausdorff measure is a generalization of the lebesgue measure to sets with non - integer dimension, in particular, fractal sets. every probability space gives rise to a measure which takes the value 1 on the whole space ( and therefore takes all its values in the unit interval [ 0, 1 ] ). such a measure is called a probability measure or distribution. see the list of probability distributions for instances. the dirac measure δa ( cf. dirac delta function ) is given by δa ( s ) = χs ( a ), where χs is the indicator function of s. { \ displaystyle s. } the measure of a set is 1 if it contains the point a { \ displaystyle a } and 0 otherwise. other ' named ' measures used in various theories include : borel measure, jordan measure, ergodic measure, gaussian measure, baire measure, radon measure, young measure, and loeb measure. in physics an example of a measure is spatial distribution of mass ( see for example, gravity potential ), or another non - negative extensive property, conserved ( see conservation law for a list of these ) or not. negative values lead to signed measures, see " generalizations " below. liouville measure, known also as the natural volume form on a symplectic manifold, is useful in classical statistical and hamiltonian mechanics. gibbs measure is widely used in statistical mechanics, often under the name canonical ensemble. measure theory is used in | https://en.wikipedia.org/wiki/Measure_(mathematics) |
we propose a novel generative model architecture designed to learn representations for images that factor out a single attribute from the rest of the representation. a single object may have many attributes which when altered do not change the identity of the object itself. consider the human face ; the identity of a particular person is independent of whether or not they happen to be wearing glasses. the attribute of wearing glasses can be changed without changing the identity of the person. however, the ability to manipulate and alter image attributes without altering the object identity is not a trivial task. here, we are interested in learning a representation of the image that separates the identity of an object ( such as a human face ) from an attribute ( such as ' wearing glasses ' ). we demonstrate the success of our factorization approach by using the learned representation to synthesize the same face with and without a chosen attribute. we refer to this specific synthesis process as image attribute manipulation. we further demonstrate that our model achieves competitive scores, with state of the art, on a facial attribute classification task. | arxiv:1711.05175 |
in this paper we explore the intersection of the hassett divisor $ \ mathcal c _ 8 $, parametrizing smooth cubic fourfolds $ x $ containing a plane $ p $ with other divisors $ \ mathcal c _ i $. notably we study the irreducible components of the intersections with $ \ mathcal { c } _ { 12 } $ and $ \ mathcal { c } _ { 20 } $. these two divisors generically parametrize respectively cubics containing a smooth cubic scroll, and a smooth veronese surface. first, we find all the irreducible components of the two intersections, and describe the geometry of the generic elements in terms of the intersection of $ p $ with the other surface. then we consider the problem of rationality of cubics in these components, either by finding rational sections of the quadric fibration induced by projection off $ p $, or by finding examples of reducible one - apparent - double - point surfaces inside $ x $. finally, via some macaulay computations, we give explicit equations for cubics in each component. | arxiv:2409.12032 |
we extend ( and somewhat simplify ) the algebraic proof technique of guth and katz \ cite { gk }, to obtain several sharp bounds on the number of incidences between lines and points in three dimensions. specifically, we show : ( i ) the maximum possible number of incidences between $ n $ lines in $ \ reals ^ 3 $ and $ m $ of their joints ( points incident to at least three non - coplanar lines ) is $ \ theta ( m ^ { 1 / 3 } n ) $ for $ m \ ge n $, and $ \ theta ( m ^ { 2 / 3 } n ^ { 2 / 3 } + m + n ) $ for $ m \ le n $. ( ii ) in particular, the number of such incidences cannot exceed $ o ( n ^ { 3 / 2 } ) $. ( iii ) the bound in ( i ) also holds for incidences between $ n $ lines and $ m $ arbitrary points ( not necessarily joints ), provided that no plane contains more than o ( n ) points and each point is incident to at least three lines. as a preliminary step, we give a simpler proof of ( an extension of ) the bound $ o ( n ^ { 3 / 2 } ) $, established by guth and katz, on the number of joints in a set of $ n $ lines in $ \ reals ^ 3 $. we also present some further extensions of these bounds, and give a proof of bourgain ' s conjecture on incidences between points and lines in 3 - space, which constitutes a simpler alternative to the proof of \ cite { gk }. | arxiv:0905.1583 |
we present a calculation of the generalized parton distributions of the photon using overlaps of photon light - front wave functions. | arxiv:1109.6755 |
the first gamma - ray burst detections by imaging atmospheric cherenkov telescopes have been recently announced : grb 190114c, detected by magic, grb 180720b and grb 190829a, observed by h. e. s. s. a dedicated search for neutrinos in space and time coincidence with the gamma - ray emission observed by iacts has been performed using antares data. the search covers both the prompt and afterglow phases, yielding no neutrinos in coincidence with the three grbs studied. upper limits on the energetics of the neutrino emission are inferred. the resulting upper limits are several orders of magnitude above the observed gamma - ray emission, and they do not allow to constrain the available models. | arxiv:2011.11411 |
we study the geometrical meaning of the faa ' di bruno polynomials in the context of kp theory. they provide a basis in a subspace w of the universal grassmannian associated to the kp hierarchy. when w comes from geometrical data via the krichever map, the faa ' di bruno recursion relation turns out to be the cocycle condition for ( the welters hypercohomology group describing ) the deformations of the dynamical line bundle on the spectral curve together with the meromorphic sections which give rise to the krichever map. starting from this, one sees that the whole kp hierarchy has a similar cohomological meaning. | arxiv:solv-int/9704010 |
text ranking has witnessed significant advancements, attributed to the utilization of dual - encoder enhanced by pre - trained language models ( plms ). given the proliferation of available plms, selecting the most effective one for a given dataset has become a non - trivial challenge. as a promising alternative to human intuition and brute - force fine - tuning, transferability estimation ( te ) has emerged as an effective approach to model selection. however, current te methods are primarily designed for classification tasks, and their estimated transferability may not align well with the objectives of text ranking. to address this challenge, we propose to compute the expected rank as transferability, explicitly reflecting the model ' s ranking capability. furthermore, to mitigate anisotropy and incorporate training dynamics, we adaptively scale isotropic sentence embeddings to yield an accurate expected rank score. our resulting method, adaptive ranking transferability ( airtran ), can effectively capture subtle differences between models. on challenging model selection scenarios across various text ranking datasets, it demonstrates significant improvements over previous classification - oriented te methods, human intuition, and chatgpt with minor time consumption. | arxiv:2409.16198 |
gravitational - wave astronomy provides a unique new way to study the expansion history of the universe. in this work, we investigate the impact future gravitational - wave observatories will have on cosmology. third - generation observatories like the einstein telescope and cosmic explorer will be sensitive to essentially all of the binary black hole coalescence events in the universe. recent work by \ cite { farr2019future } points out that features in the stellar - mass black hole population break the mass - redshift degeneracy, facilitating precise determination of the hubble parameter without electromagnetic counterparts or host galaxy catalogues. using a hierarchical bayesian inference model, we show that with one year of observations by the einstein telescope, the hubble constant will be measured to $ \ lesssim 1 \ % $. we also show that this method can be used to perform bayesian model selection between cosmological models. as an illustrative example, we find that a decisive statement can be made comparing the $ \ lambda $ cdm and rhct cosmological models using two weeks of data from the einstein telescope. | arxiv:2004.00036 |
we investigate the low - energy properties of antiferromagnetic quantum xxz spin chains with couplings following two - letter aperiodic sequences, by an adaptation of the ma - dasgupta - hu renormalization - group method. for a given aperiodic sequence, we argue that in the easy - plane anisotropy regime, intermediate between the xx and heisenberg limits, the general scaling form of the thermodynamic properties is essentially given by the exactly known xx behavior, providing a classification of the effects of aperiodicity on xxz chains. as representative illustrations, we present analytical and numerical results for the low - temperature thermodynamics and the ground - state correlations for couplings following the fibonacci quasiperiodic structure and a binary rudin - shapiro sequence, whose geometrical fluctuations are similar to those induced by randomness. | arxiv:cond-mat/0403635 |
we report production of nanostructured carbon foam by a high - repetition - rate, high - power laser ablation of glassy carbon in ar atmosphere. a combination of characterization techniques revealed that the system contains both sp2 and sp3 bonded carbon atoms. the material is a novel form of carbon in which graphite - like sheets fill space at very low density due to strong hyperbolic curvature, as proposed for? schwarzite?. the foam exhibits ferromagnetic - like behaviour up to 90 k, with a narrow hysteresis curve and a high saturation magnetization. such magnetic properties are very unusual for a carbon allotrope. detailed analysis excludes impurities as the origin of the magnetic signal. we postulate that localized unpaired spins occur because of topological and bonding defects associated with the sheet curvature, and that these spins are stabilized due to the steric protection offered by the convoluted sheets. | arxiv:cond-mat/0310751 |
in cognitive radio networks ( crns ), the connectivity of secondary users ( sus ) is difficult to be guaranteed due to the existence of primary users ( pus ). most prior studies only consider cognitive radio networks equipped with omni - directional antennas causing high interference at sus. we name such crns with omni - directional antennas as omn - crns. compared with an omni - directional antenna, a directional antenna can concentrate the transmitting / receiving capability at a certain direction, consequently resulting in less interference. in this paper, we investigate the connectivity of sus in crns with directional antennas ( named as dir - crns ). in particular, we derive closed - form expressions of the connectivity of sus of both dir - crns and omn - crns, thus enabling tractability. we show that the connectivity of sus is mainly affected by two constraints : the spectrum availability of sus and the topological connectivity of sus. extensive simulations validate the accuracy of our proposed models. meanwhile, we also show that dir - crns can have higher connectivity than omn - crns mainly due to the lower interference, the higher spectrum availability and the higher topological connectivity brought by directional antennas. | arxiv:1804.02658 |
in this paper, we present a homogeneous analysis of close - in neptune planets. to do this, we compile a sample of tess - observed planets using a ranking criterion which takes into account the planet ' s period, radius, and the visual magnitude of its host star. we use archival and new harps data to ensure every target in this sample has precise radial velocities. this yields a total of 64 targets, 46 of which are confirmed planets and 18 of which show no significant radial velocity signal. we explore the mass - radius distribution, planetary density, stellar host metallicity, and stellar and planetary companions of our targets. we find 26 $ \ % $ of our sample are in multi - planet systems, which are typically seen for planets located near the lower edge of the neptunian desert. we define a ' gold ' subset of our sample consisting of 33 confirmed planets with planetary radii between 2 $ r _ { \ oplus } $ and 10 $ r _ { \ oplus } $. with these targets, we calculate envelope mass fractions ( emf ) using the gas giant model for interiors ( gastli ). we find a clear split in emf between planets with equilibrium temperatures below and above 1300 ~ k, equivalent to an orbital period of $ \ sim $ 3. 5 ~ days. below this period, emfs are consistent with zero, while above they typically range from 20 $ \ % $ to 40 $ \ % $, scaling linearly with the planetary mass. the orbital period separating these two populations coincides with the transition between the neptunian desert and the recently identified neptunian ridge, further suggesting that different formation and / or evolution mechanisms are at play for neptune planets across different close - in orbital regions. | arxiv:2504.16164 |
large efforts in improving thermoelectric energy conversion are devoted to energy filtering by nanometer size potential barriers. in this work we perform an analysis and optimization of such barriers for improved energy filtering. we merge semiclassical with quantum mechanical simulations to capture tunneling and reflections due to the barrier, and analyze the influence of the width w, the height vb, and the shape of the barrier, and the position of the fermi level ( ef ) above the band edge, { \ eta } f. we show that for an optimized design, approx. 40 per cent improvement in the thermoelectric power factor can be achieved if the following conditions are met : { \ eta } f is large ; the different of vb from ef is somewhat higher but comparable to kbt ; and w is large enough to suppress tunneling. finally, we show that a smooth energy barrier is beneficial compared to a sharp ( square ) barrier for increasing the thermoelectric power factor. | arxiv:1307.8156 |
we present near - infrared spectra of ` ` a2 ' ', the primary counter arc to the gravitationally lensed galaxy ms1512 - cb58. the spectra showredshifted h - alpha, [ nii ], [ oiii ], and h - beta at z = 2. 728 + / - 0. 001. we observe the same h - alpha / [ oiii ] ratio as cb58, which together with the redshift confirms that a2 is indeed another image of a single background galaxy. published lensing reconstruction reports that a2 is a magnification of the entire source, while cb58 is an image of only a part. at marginal significance, a2 shows higher line to continuum ratios than cb58 ( by a factor of about 2 ), suggesting a non - uniform ratio of young to old stars across the galaxy. we observe a second emission line source in the slit. this object, ` ` w5 ' ', is predicted to be a lensed image of another galaxy at a redshift similar to cb58. w5 is blueshifted from cb58 by about 400 km / s and has a significantly lower h - alpha / [ oiii ] ratio, confirming that it is an image of a different background galaxy in a group with cb58. the h - alpha emission line in w5 implies a star formation rate of 6 msun / yr ( h _ 0 = 70 km / s / mpc, omega _ m = 0. 3, omega _ l = 0. 7 ), after correcting for lensing magnification. | arxiv:astro-ph/0402519 |
we present an improvement of our implementation of the correlation technique for the fourier domain acceleration search ( fdas ) algorithm on graphics processor units ( gpus ) ( dimoudi & armour 2015 ; dimoudi et al. 2017 ). our new improved convolution code which uses our custom gpu fft code is between 2. 5 and 3. 9 times faster the than our cufft - based implementation ( on an nvidia p100 ) and allows for a wider range of filter sizes then our previous version. by using this new version of our convolution code in fdas we have achieved 44 % performance increase over our previous best implementation. it is also approximately 8 times faster than the existing presto gpu implementation of fdas ( luo 2013 ). this work is part of the astroaccelerate project ( armour et al. 2002 ), a many - core accelerated time - domain signal processing library for radio astronomy. | arxiv:1711.10855 |
we study the soliton mobility in nonlocal nonlinear media with an imprinted fading optical lattice. the results show that the transverse mobility of solitons varies with the lattice decay rate and the nonlocality degree, which provides an opportunity for all - optical control of light. | arxiv:1302.6147 |
this paper presents a framework for the study of convergence when the nodes ' dynamics may be both piecewise smooth and / or nonidentical across the network. specifically, we derive sufficient conditions for global convergence of all node trajectories towards the same bounded region of their state space. the analysis is based on the use of set - valued lyapunov functions and bounds are derived on the minimum coupling strength required to make all nodes in the network converge towards each other. we also provide an estimate of the asymptotic bound $ \ epsilon $ on the mismatch between the node states at steady state. the analysis is performed both for linear and nonlinear coupling protocols. the theoretical analysis is extensively illustrated and validated via its application to a set of representative numerical examples. | arxiv:1404.1835 |
psr j2021 + 3651 is a 17 kyr old rotation powered pulsar detected in the radio, x - rays, and $ \ gamma $ - rays. it powers a torus - like pulsar wind nebula with jets, dubbed the dragonfly, which is very similar to that of the vela pulsar. the dragonfly is likely associated with the extended tev source ver j2019 + 368 and extended radio emission. we conducted first deep optical observations with the gtc in the sloan $ r ' $ band to search for optical counterparts of the pulsar and its nebula. no counterparts were detected down to $ r ' \ gtrsim27. 2 $ and $ \ gtrsim24. 8 $ for the point - like pulsar and the compact x - ray nebula, respectively. we also reanalyzed chandra archival x - ray data taking into account an interstellar extinction - - distance relation, constructed by us for the dragonfly line of sight using the red - clump stars as standard candles. this allowed us to constrain the distance to the pulsar, $ d = 1. 8 ^ { + 1. 7 } _ { - 1. 4 } $ kpc at 90 % confidence. it is much smaller than the dispersion measure distance of $ \ sim $ 12 kpc but compatible with a $ \ gamma $ - ray " pseudo - distance " of 1 kpc. based on that and the optical upper limits, we conclude that psr j2021 + 3651, similar to the vela pulsar, is a very inefficient nonthermal emitter in the optical and x - rays, while its $ \ gamma $ - ray efficiency is consistent with an average efficiency for $ \ gamma $ - pulsars of similar age. our optical flux upper limit for the pulsar is consistent with the long - wavelength extrapolation of its x - ray spectrum while the nebula flux upper limit does not constrain the respective extrapolation. | arxiv:1501.04594 |
we present an accurate and efficient algorithm to calculate the electrostatic interaction of charged point particles with partially periodic boundary conditions that are confined along the nonperiodic direction by two metallic parallel plates. the method preserves the original boundary conditions and hence, it does not introduce any kind of artifacts. in addition, it enjoys the quasilinear complexity of $ \ mathcal { o } ( n \ ln ( n ) ) $, where $ n $ being the number of particles in the simulation box. in fact, based on the superposition principle in electrostatics, the problem is split into two electrostatic problems where each one can be calculated by the appropriate poisson solver. in this paper we apply the method to sodium chloride ultrathin films and investigate its dielectric response with respect to external bias voltage. we show how accurately in this method one can obtain the total charge induced on metallic boundaries to an arbitrary precision. | arxiv:1512.07387 |
in earlier work generalizing a 1977 theorem of alladi, the authors proved a partition - theoretic formula to compute arithmetic densities of certain subsets of the positive integers $ \ mathbb n $ as limiting values of $ q $ - series as $ q \ to \ zeta $ a root of unity ( instead of using the usual dirichlet series to compute densities ), replacing multiplicative structures of $ \ mathbb n $ by analogous structures in the integer partitions $ \ mathcal p $. in recent work, wang obtains a wide generalization of alladi ' s original theorem, in which arithmetic densities of subsets of prime numbers are computed as values of dirichlet series arising from dirichlet convolutions. here the authors prove that wang ' s extension has a partition - theoretic analogue as well, yielding new $ q $ - series density formulas for any subset of $ \ mathbb n $. to do so, we outline a theory of $ q $ - series density calculations from first principles, based on a statistic we call the " $ q $ - density " of a given subset. this theory in turn yields infinite families of further formulas for arithmetic densities. | arxiv:2010.15107 |
the properties of fast radio bursts ( frbs ) indicate that the physical origin of this type of astrophysical phenomenon is related to neutron stars. the first detected repeating source, frb 121102, is associated with a persistent radio counterpart. in this paper, we propose that this radio counterpart could arise from a pulsar wind nebula powered by a magnetar without surrounding supernova ejecta. its medium is a stratified structure produced by a progenitor wind. the model parameters are constrained by the spectrum of the counterpart emission, the size of the nebula, and the large but decreasing rotation measure ( rm ) of the repeating bursts. in addition, the observed dispersion measure is consistent with the assumption that all of the rm comes from the shocked medium. | arxiv:1911.12833 |
the abnormally weighting energy ( awe ) hypothesis consists of assuming that the dark sector of cosmology violates the weak equivalence principle ( wep ) on cosmological scales, which implies a violation of the strong equivalence principle for ordinary matter. in this paper, dark energy ( de ) is shown to result from the violation of wep by pressureless ( dark ) matter. this allows us to build a new cosmological framework in which general relativity ( gr ) is satisfied at low scales, as wep violation depends on the ratio of the ordinary matter over dark matter densities, but at large scales, we obtain a general relativity - like theory with a different value of the gravitational coupling. this explanation is formulated in terms of a tensor - scalar theory of gravitation without wep for which there exists a revisited convergence mechanism toward gr. the consequent de mechanism build upon the anomalous gravity of dark matter ( i ) does not require any violation of the strong energy condition $ p < - \ rho c ^ 2 / 3 $, ( ii ) offers a natural way - out of the coincidence problem thanks to the non - minimal couplings to gravitation, ( iii ) accounts fairly for supernovae data from various very simple couplings and with density parameters very close to the ones of the concordance model $ \ lambda cdm $, therefore suggesting an explanation to its remarkable adequacy. finally, ( iv ) this mechanism ends up in the future with an einstein - de sitter expansion regime once the attractor is reached. | arxiv:astro-ph/0702478 |
the facilitation of rydberg excitations in a gas of atoms provides an ideal model system to study epidemic evolution on ( dynamic ) networks and self organization of complex systems to the critical point of a non - equilibrium phase transition. using monte - carlo simulations and a machine learning algorithm we show that the universality class of this phase transition can be tuned. the classes include directed percolation ( dp ), the most common class in short - range spreading models, and mean - field ( mf ) behavior, but also different types of anomalous directed percolation ( adp ), characterized by rare long - range excitation processes. in a frozen gas, ground state atoms that can facilitate each other form a static network, for which we predict dp universality. atomic motion then turns the network into a dynamic one with long - range ( levy - flight type ) excitations. this leads to continuously varying critical exponents corresponding to the adp universality class, eventually reaching mf behavior. these findings also explain the recently observed critical exponent of rydberg facilitation in an ultra - cold gas experiment [ helmrich et al., nature 577, 481 ( 2020 ) ], which was in between dp and mf values. | arxiv:2404.16523 |
we study the impacts of magnetic field on the neutrino transport inside core - collapse supernovae ( ccsne ). magnetic field quantizes the momentum of electrons and positrons, resulting in the modification of weak - interaction cross sections and the chemical potentials of electrons and positrons. we include these changes in the leakage scheme of neutrino transport and perform 1d ccsn simulations with gr1d, assuming the postbounce magnetic field strength of $ 10 ^ { 16 - 17 } $ g. the results show that the neutrino opacities are enhanced due to the amplified interaction rates, resulting in a larger neutrinosphere. this further reduces the peak value of neutrino luminosities and their decay rates since neutrinos stay longer inside the neutrinosphere. meanwhile, the neutrino mean energies are smaller shortly after bounce and reach their peak values at later times. as these neutrino properties are crucial in subsequent nucleosynthesis processes, including the $ \ nu $ p - process, $ \ nu $ - process, and $ r $ - process, our findings suggest that the magnetic field may leave discernible marks on the abundance pattern of nucleosynthesis in ccsn. | arxiv:2405.11555 |
in frames of a rather conventional cluster approach, which combines the crystal field and the ligand field models we have considered different charge transfer ( ct ) states and o 2p - mn 3d ct transitions in mno $ _ { 6 } ^ { 9 - } $ octahedra. the many - electron dipole transition matrix elements were calculated using the racah algebra for the cubic point group. simple " local " approximation allowed to calculate the relative intensity for all dipole - allowed $ \ pi - \ pi $ and $ \ sigma - \ sigma $ ct transitions. we present a self - consistent description of the ct bands in insulating stoichiometric lamn $ ^ { 3 + } $ o $ _ 3 $ compound with the only mn $ ^ { 3 + } $ valent state and idealized octahedral mno $ _ { 6 } ^ { 9 - } $ centers which allows to substantially correct the current interpretation of the optical spectra. our analysis shows the multi - band structure of the ct optical response with the weak low - energy edge at 1. 7 ev, associated with forbidden $ t _ { 1g } ( \ pi ) - e _ { g } $ transition and a series of the weak and strong dipole - allowed high - energy transitions starting from 2. 5 and 4. 5 ev, respectively, and extending up to nearly 11 ev. the most intensive features are associated with two strong composite bands near $ 4. 6 \ div 4. 7 $ ev and $ 8 \ div 9 $ ev, respectively, resulting from the superposition of the dipole - allowed $ \ sigma - \ sigma $ and $ \ pi - \ pi $ ct transitions. these predictions are in good agreement with experimental spectra. the experimental data point to a strong overscreening of the crystal field parameter $ dq $ in the ct states of mno $ _ { 6 } ^ { 9 - } $ centers. | arxiv:cond-mat/0111198 |
in several real - world applications in medical and control engineering, there are unsafe solutions whose evaluations involve inherent risk. this optimization setting is known as safe optimization and formulated as a specialized type of constrained optimization problem with constraints for safety functions. safe optimization requires performing efficient optimization without evaluating unsafe solutions. a few studies have proposed the optimization methods for safe optimization based on bayesian optimization and the evolutionary algorithm. however, bayesian optimization - based methods often struggle to achieve superior solutions, and the evolutionary algorithm - based method fails to effectively reduce unsafe evaluations. this study focuses on cma - es as an efficient evolutionary algorithm and proposes an optimization method termed safe cma - es. the safe cma - es is designed to achieve both safety and efficiency in safe optimization. the safe cma - es estimates the lipschitz constants of safety functions transformed with the distribution parameters using the maximum norm of the gradient in gaussian process regression. subsequently, the safe cma - es projects the samples to the nearest point in the safe region constructed with the estimated lipschitz constants. the numerical simulation using the benchmark functions shows that the safe cma - es successfully performs optimization, suppressing the unsafe evaluations, while the existing methods struggle to significantly reduce the unsafe evaluations. | arxiv:2405.10534 |
in quantum electrodynamics, optical processes are theoretically described by double - sided feynman diagrams. this formalism is powerful in the case of molecules but proves inappropriate to account for light - matter interactions within complex hybrid systems constituted of organic and inorganic matter. the double - sided feynman diagrams do not easily enable to implement the coupling between the electronic properties of the former and the vibrational response of the latter. here we present a new general method bridging optics and condensed matter physics in order to properly account for the underlying fundamental process thanks to the classical feynman diagrams dedicated to solid state physics, instead of the double - sided diagrams commonly used in nonlinear optics. in a manner both rigorous and pedagogical, we especially show how feynman diagrams can be used to analytically derive the quantum expressions of second - order optical response functions which prove to be in complete agreement with previously established experimental results. | arxiv:1906.03197 |
we report on stacked multiple quantum dots ( qds ) formed inside inverted pyramidal recesses, which allow for the precise positioning of the qds themselves. specifically we fabricated double qds with varying inter - dot distance and ensembles with more than two nominally highly symmetric qds. for each, the effect of the interaction between qds is studied by characterizing a large number of qds through photoluminescence spectroscopy. a clear red - shift of the emission energy is observed together with a change in the orientation of its polarization, suggesting an increasing interaction between the qds. finally we show how stacked qds can help influencing the charging of the excitonic complexes. | arxiv:1708.09758 |
dielectron production in the $ \ pi n $ interaction at not large energies is studied. the dominant contribution of the $ \ delta $ - isobar creation in the intermediate state at incident pion momenta of about 0. 3 - 0. 4 gev $ / $ c is shown. the experimental distributions over the angle and effective mass $ m _ { e ^ + e _ - } $ of the $ e ^ + e ^ - $ pair are described satisfactorily. this stimulated us to present theoretical predictions for the $ m _ { e ^ + e _ - } $ distribution in the process $ \ pi ^ - p \ rightarrow ne ^ + e ^ - $ at different incident momenta, which could be verified, for example, by the hades experiments. | arxiv:1705.07446 |
we report on an experimental study of light pulse propagation and storage in a rb atomic vapor for different pulse durations, magnetic fields, and atomic densities, and for two different isotopes. the results have been analyzed and compared with previous studies. | arxiv:quant-ph/0410158 |
although diffusion model has shown great potential for generating higher quality images than gans, slow sampling speed hinders its wide application in practice. progressive distillation is thus proposed for fast sampling by progressively aligning output images of $ n $ - step teacher sampler with $ n / 2 $ - step student sampler. in this paper, we argue that this distillation - based accelerating method can be further improved, especially for few - step samplers, with our proposed \ textbf { c } lassifier - based \ textbf { f } eature \ textbf { d } istillation ( cfd ). instead of aligning output images, we distill teacher ' s sharpened feature distribution into the student with a dataset - independent classifier, making the student focus on those important features to improve performance. we also introduce a dataset - oriented loss to further optimize the model. experiments on cifar - 10 show the superiority of our method in achieving high quality and fast sampling. code is provided at \ url { https : / / github. com / zju - swj / rcfd }. | arxiv:2211.12039 |
the connection between the anomalous dimension and some invariance properties of the fixed point actions within exact rg is explored. as an application, polchinski equation at next - to - leading order in the derivative expansion is studied. for the wilson fixed point of the one - component scalar theory in three dimensions we obtain the critical exponents \ eta = 0. 042, \ nu = 0. 622 and \ omega = 0. 754. | arxiv:hep-th/9705129 |
in this paper we introduce a spectra preserving relation between graphs with loops and graphs without loops. this relation is achieved in two steps. first, by generalizing spectra results got on ( m, k ) - stars to a wider class of graphs, the ( m, k, s ) - stars with or without loops. second, by defining a covering space of graphs with loops that allows to remove the presence of loops by increasing the graph dimension. the equivalence of the two class of graphs allows to study graph with loops as simple graph without loosing information. | arxiv:1804.05988 |
we investigate the full and half - shells of pb ( 1 - x ) sn ( x ) te topological crystalline insulator deposited by molecular beam epitaxy on the sidewalls of wurtzite gaas nanowires ( nws ). due to the distinct orientation of the iv - vi shell with respect to the iii - v core the lattice mismatch along the nanowire axis is less than 4 %. the pb ( 1 - x ) sn ( x ) te solid solution is chosen due to the topological crystalline insulator properties for some critical concentrations of sn ( x > = 0. 4 ). the iv - vi shells are grown with different compositions spanning from binary snte, through pb ( 1 - x ) sn ( x ) te with decreasing x value down to binary pbte ( x = 0 ). the samples are analyzed by scanning transmission electron microscopy, which reveals the presence of ( 110 ) or ( 100 ) oriented binary pbte and ( 100 ) pb ( 1 - x ) sn ( x ) te on the sidewalls of wurtzite gaas nws. | arxiv:2211.08154 |
one of the most important senses in human life is vision, without it life is totally filled with darkness. according to who globally millions of people are visually impaired estimated there are 285 million, of whom some millions are blind. unfortunately, there are around 2. 4 million people are blind in our beloved country pakistan. human are a crucial part of society and the blind community is a main part of society. the technologies are grown so far to make the life of humans easier more comfortable and more reliable for. however, this disability of the blind community would reduce their chance of using such innovative products. therefore, the visually impaired community believe that they are burden to other societies and they do not capture in normal activities separates the blind people from society and because of this believe did not participate in the normally tasks of society. the visual impair people mainly face most of the problems in this real - time the aim of this work is to turn the real time world into an audio world by telling blind person about the objects in their way and can read printed text. this will enable blind persons to identify the things and read the text without any external help just by using the object detection and reading system in real time. objective of this work : i ) object detection ii ) read printed text, using state - of - the - art ( sota ) technology. | arxiv:2212.00004 |
we present results of two pilot studies that investigated human error behaviours with an error prone in - air gesture recognizer. during the studies, users performed a small set of simple in - air gestures. in the first study, these gestures were abstract. the second study associated concrete tasks with each gesture. interestingly, the error patterns observed in the two studies were substantially different. | arxiv:2105.12453 |
we investigate the nonequilibrium dynamics of classical particles in a driven quasiperiodic lattice based on the fibonacci sequence. an intricate transient dynamics of extraordinarily long ballistic flights at distinct velocities is found. we argue how these transients are caused and can be under - stood by a hierarchy of block decompositions of the quasiperiodic lattice. a comparison to the cases of periodic and fully randomized lattices is performed. | arxiv:1602.01356 |
we compute explicit solutions $ \ lambda ^ \ pm _ m $ of the painleve vi ( pvi ) differential equation from equivariant instanton bundles $ e _ m $ corresponding to yang - mills instantons with " quadrupole symmetry. " this is based on a generalization of hitchin ' s logarithmic connection to vector bundles with an $ sl _ 2 ( { \ mathbb c } ) $ action. we then identify explicit okamoto transformation which play the role of " creation operators " for construction $ \ lambda ^ \ pm _ m $ from the " ground state " $ \ lambda ^ \ pm _ 0 $, suggesting that the equivariant instanton bundles $ e _ m $ might similarly be related to the trivial " ground state " $ e _ 0 $. | arxiv:2103.06321 |
it is well - known that the coefficients in faa di bruno ' s chain rule for higher derivatives can be expressed via numeration of partitions. it turns out that this has a natural form as a formula for the vector case. to this formula two proofs are presented, both " explaining " its form involving partitions : one as a purely algebraic fact, and one " from first principles " for the case of frechet derivatives of mappings between banach spaces. | arxiv:math/0602183 |
we present a calculation of the global polarization of lambda hyperons in relativistic au - au collisions at rhic beam energy scan range sqrt { s } _ nn = 7. 7 - 200 gev with a 3 + 1 dimensional cascade + viscous hydro + cascade model, urqmd + vhlle. within this model, the mean polarization of lambda in the out - of - plane direction is predicted to decrease rapidly with collision energy from a top value of about 2 % at the lowest energy examined. we explore the connection between the polarization signal and thermal vorticity and estimate the feed - down contribution to lambda polarization due to the decay of higher mass hyperons. | arxiv:1610.04717 |
here we present a kinematic study of the galactic halo out to a radius of $ \ sim $ 60 kpc, using 4664 blue horizontal branch ( bhb ) stars selected from the sdss / segue survey, to determine key dynamical properties. using a maximum likelihood analysis, we determine the velocity dispersion profiles in spherical coordinates ( $ \ sigma _ { r } $, $ \ sigma _ { \ theta } $, $ \ sigma _ { \ phi } $ ) and the anisotropy profile ( $ \ beta $ ). the radial velocity dispersion profile ( $ \ sigma _ { r } $ ) is measured out to a galactocentric radius of $ r \ sim 60 $ kpc, but due to the lack of proper - motion information, $ \ sigma _ { \ theta } $, $ \ sigma _ { \ phi } $ and $ \ beta $ could only be derived directly out to $ r \ sim25 $ kpc. from a starting value of $ \ beta \ approx 0. 5 $ in the inner parts ( $ 9 < r / \ kpc < 12 $ ), the profile falls sharply in the range $ r \ approx 13 - 18 $ kpc, with a minimum value of $ \ beta = - 1. 2 $ at $ r = 17 $ kpc, rising sharply at larger radius. in the outer parts, in the range $ 25 < r / \ kpc < 56 $, we predict the profile to be roughly constant with a value of $ \ beta \ approx 0. 5 $. the newly discovered kinematic anomalies are shown not to arise from halo substructures. we also studied the anisotropy profile of simulated stellar halos formed purely by accretion and found that they cannot reproduce the sharp dip seen in the data. from the jeans equation, we compute the stellar rotation curve ( $ v _ { \ rm circ } $ ) of the galaxy out to $ r \ sim 25 $ kpc. the mass of the galaxy within $ r \ lesssim 25 $ kpc is determined to be $ 2. 1 \ times 10 ^ { 11 } $ $ m _ { \ sun } $, and with a 3 - component fit to $ v _ { \ rm circ } ( r ) $, we determine the virial mass of the milky way dark matter halo to be $ m _ { \ rm vir } = 0. 9 ^ { + | arxiv:1210.7527 |
timed discrete - event systems ( tdes ), which is a modelling formalism proposed by brandin and wonham, can be used for modelling scheduling and production planning problems. this paper aims to show that tdes are essentially synchronous product structures. the proof is constructive in the sense that a generalized synchronous product rule is provided to generate a tdes from the activity automaton and the timer automata ( that is, the syntactic description of the tdes ) after some model transformation. we then also explain how the generalized synchronous product operation can be reduced into the standard synchronous product operation and how to reduce the number of ( refined ) events introduced in the model transformation. thus, any software that can compute synchronous products can be used to compute a tdes from its activity automaton and its timer automata, after the model transformation. | arxiv:1807.06725 |
this paper studies the problem of zero - shot sketch - based image retrieval ( zs - sbir ), which aims to use sketches from unseen categories as queries to match the images of the same category. due to the large cross - modality discrepancy, zs - sbir is still a challenging task and mimics realistic zero - shot scenarios. the key is to leverage transferable knowledge from the pre - trained model to improve generalizability. existing researchers often utilize the simple fine - tuning training strategy or knowledge distillation from a teacher model with fixed parameters, lacking efficient bidirectional knowledge alignment between student and teacher models simultaneously for better generalization. in this paper, we propose a novel symmetrical bidirectional knowledge alignment for zero - shot sketch - based image retrieval ( sbka ). the symmetrical bidirectional knowledge alignment learning framework is designed to effectively learn mutual rich discriminative information between teacher and student models to achieve the goal of knowledge alignment. instead of the former one - to - one cross - modality matching in the testing stage, a one - to - many cluster cross - modality matching method is proposed to leverage the inherent relationship of intra - class images to reduce the adverse effects of the existing modality gap. experiments on several representative zs - sbir datasets ( sketchy ext dataset, tu - berlin ext dataset and quickdraw ext dataset ) prove the proposed algorithm can achieve superior performance compared with state - of - the - art methods. | arxiv:2312.10320 |
aims. in this paper we study the spitzer and timmi2 infrared spectra of post - agb disc sources, both in the galaxy and the lmc. using the observed infrared spectra we determine the mineralogy and dust parameters of the discs, and look for possible differences between the galactic and extragalactic sources. methods. modelling the full spectral range observed allows us to determine the dust species present in the disc and different physical parameters such as grain sizes, dust abundance ratios, and the dust and continuum temperatures. results. we find that all the discs are dominated by emission features of crystalline and amorphous silicate dust. only a few sample sources show features due to co2 gas or carbonaceous molecules such as pahs and c60 fullerenes. our analysis shows that dust grain processing in these discs is strong, resulting in large average grain sizes and a very high crystallinity fraction. however, we do not find any correlations between the derived dust parameters and properties of the central source. there also does not seem to be a noticeable difference between the mineralogy of the galactic and lmc sources. even though the observed spectra are very similar to those of protoplanetary discs around young stars, showing similar mineralogy and strong grain processing, we do find evidence for differences in the physical and chemical processes of the dust processing. | arxiv:1108.0796 |
the nasa stereo mission opened up the possibility to forecast the arrival times, speeds and directions of solar transients from outside the sun - earth line. in particular, we are interested in predicting potentially geo - effective interplanetary coronal mass ejections ( icmes ) from observations of density structures at large observation angles from the sun ( with the stereo heliospheric imager instrument ). we contribute to this endeavor by deriving analytical formulas concerning a geometric correction for the icme speed and arrival time for the technique introduced by davies et al. ( 2012, apj, in press ) called self - similar expansion fitting ( ssef ). this model assumes that a circle propagates outward, along a plane specified by a position angle ( e. g. the ecliptic ), with constant angular half width ( lambda ). this is an extension to earlier, more simple models : fixed - phi - fitting ( lambda = 0 degree ) and harmonic mean fitting ( lambda = 90 degree ). this approach has the advantage that it is possible to assess clearly, in contrast to previous models, if a particular location in the heliosphere, such as a planet or spacecraft, might be expected to be hit by the icme front. our correction formulas are especially significant for glancing hits, where small differences in the direction greatly influence the expected speeds ( up to 100 - 200 km / s ) and arrival times ( up to two days later than the apex ). for very wide icmes ( 2 lambda > 120 degree ), the geometric correction becomes very similar to the one derived by m \ " ostl et al. ( 2011, apj, 741, id. 34 ) for the harmonic mean model. these analytic expressions can also be used for empirical or analytical models to predict the 1 au arrival time of an icme by correcting for effects of hits by the flank rather than the apex, if the width and direction of the icme in a plane are known and a circular geometry of the icme front is assumed. | arxiv:1202.1299 |
the gaia collaboration has recently reported the detection of a 33 m $ _ \ odot $ black hole in a wide binary system located in the solar neighbourhood. here we explore the relationship between this black hole, known as gaia bh3, and the nearby ed - 2 halo stellar stream. we study the orbital characteristics of the gaia bh3 binary and present measurements of the chemical abundances of ed - 2 member stars derived from high - resolution spectra obtained with the vlt. we find that the galactic orbit of the gaia bh3 system and its metallicity are entirely consistent with being part of the ed - 2 stream. the characteristics of the stream, particularly its negligible spread in metallicity and in other chemical elements as well as its single stellar population, suggest that it originated from a disrupted star cluster of low mass. its age is comparable to that of the globular cluster m92 that has been estimated to be as old as the universe. this is the first black hole unambiguously associated with a disrupted star cluster. we infer a plausible mass range for the cluster to be relatively narrow, between $ 2 \ times 10 ^ 3m _ \ odot $ and $ 4. 2 \ times 10 ^ 4m _ \ odot $. this implies that the black hole could have formed directly from the collapse of a massive very - metal - poor star, but that the alternative scenario of binary interactions inside the cluster environment also deserves to be explored. | arxiv:2404.11604 |
first - principles, density - functional based electronic structure calculations are carried out for mgc ( ni _ { 1 - x } co _ { x } ) _ { 3 } alloys over the concentration range 0 \ leq x \ leq1, using korringa - kohn - rostoker coherent - potential approximation ( kkr cpa ) method in the atomic sphere approximation ( asa ). the self - consistent calculations are used to study the changes as a function of x in the equation of state parameters, total and partial densities of states, magnetic moment and the on - site exchange interaction parameter. to study the magnetic properties as well as its volume dependence, fixed - spin moment calculations in conjunction with the phenomenological landau theory are employed. the salient features that emerge from these calculations are ( i ) a concentration independent variation in the lattice parameter and bulk modulus at x ~ 0. 75 with an anomaly in the variation of the pressure derivative of bulk modulus, ( ii ) the fixed - spin moment based corrections to the overestimated magnetic ground state for 0. 0 \ leq x \ leq0. 3 alloys, making the results consistent with the experiments, and ( iii ) the possibility of multiple magnetic states at x ~ 0. 75, which, however, requires further improvements in the calculations. | arxiv:cond-mat/0508569 |
a common mechanism for intracellular transport is the use of controlled deformations of the membrane to create spherical or tubular buds. while the basic physical properties of homogeneous membranes are relatively well - known, the effects of inhomogeneities within membranes are very much an active field of study. membrane domains enriched in certain lipids in particular are attracting much attention, and in this letter we investigate the effect of such domains on the shape and fate of membrane tubes. recent experiments have demonstrated that forced lipid phase separation can trigger tube fission, and we demonstrate how this can be understood purely from the difference in elastic constants between the domains. moreover, the proposed model predicts timescales for fission that agree well with experimental findings. | arxiv:physics/0404086 |
we present here temperature - dependent raman, x - ray diffraction and specific heat studies between room temperature and 12 k on single crystals of spin - ice pyrochlore compound $ dy _ 2ti _ 2o _ 7 $ and its non - magnetic analogue $ lu _ 2ti _ 2o _ 7 $. raman data show a " new " band not predicted by factor group analysis of raman - active modes for the pyrochlore structure in $ dy _ 2ti _ 2o _ 7 $, appearing below a temperature of $ t _ c = $ 110 k with a concomitant contraction of the cubic unit cell volume as determined from the powder x - ray diffraction analysis. low temperature raman experiments on o $ ^ { 18 } $ - isotope substituted $ dy _ 2ti _ 2o _ 7 $ confirm the phonon origin of the " new " mode. these findings, absent in $ lu _ 2ti _ 2o _ 7 $, suggest that the room temperature cubic lattice of the pyrochlore $ dy _ 2ti _ 2o _ 7 $ undergoes a " subtle " structural transformation near $ t _ c $. we find anomalous \ textit { red - shift } of some of the phonon modes in both the $ dy _ 2ti _ 2o _ 7 $ and the $ lu _ 2ti _ 2o _ 7 $ as the temperature decreases, which is attributed to strong phonon - phonon anharmonic interactions. | arxiv:0812.0026 |
the holographic complexity and fidelity susceptibility have been defined as new quantities dual to different volumes in ads. in this paper, we will use these new proposals to calculate both of these quantities for a variety of interesting deformations of ads. we obtain the holographic complexity and fidelity susceptibility for an ads black hole, janus solution and a solution with cylindrically symmetry, an inhomogeneous background and a hyperscaling violating background. it is observed that the holographic complexity depends on the size of the subsystem for all these solutions and the fidelity susceptibility does not have any such dependence. | arxiv:1609.00250 |
spatiotemporal structured light has opened up new avenues for optics and photonics. current spatiotemporal manipulation of light mostly relies on phase - only devices such as liquid crystal spatial light modulator to generate spatiotemporal optical fields with unique photonic properties. however, simultaneous manipulation of both amplitude and phase of the complex field for the spatiotemporal light is still lacking, limiting the diversity and richness of achievable photonic properties. in this work, a simple and versatile spatiotemporal holographic method that can arbitrarily sculpture the spatiotemporal light is presented. the capabilities of this simple yet powerful method are demonstrated through the generation of fundamental and higher - order spatiotemporal bessel wavepacket, spatiotemporal crystal - like and quasi - crystal - like structures, and spatiotemporal flat - top wavepackets. fully customizable spatiotemporal wavepackets will find broader application in investigating the dynamics of spatiotemporal fields and interactions between ultrafast spatiotemporal pulses and matters, unveiling previously hidden light - matter interactions and unlocking breakthroughs in photonics and beyond. | arxiv:2401.12642 |
deep learning has shown the great power in the field of fault detection. however, for incipient faults with tiny amplitude, the detection performance of the current deep learning networks ( dlns ) is not satisfactory. even if prior information about the faults is utilized, dlns can ' t successfully detect faults 3, 9 and 15 in tennessee eastman process ( tep ). these faults are notoriously difficult to detect, lacking effective detection technologies in the field of fault detection. in this work, we propose autoencoder - assisted feature ensemble net ( ae - fenet ) : a deep feature ensemble framework that uses the unsupervised autoencoder to conduct the feature transformation. compared with the principle component analysis ( pca ) technique adopted in the original feature ensemble net ( fenet ), autoencoder can mine more exact features on incipient faults, which results in the better detection performance of ae - fenet. with same kinds of basic detectors, ae - fenet achieves a state - of - the - art average accuracy over 96 % on faults 3, 9 and 15 in tep, which represents a significant enhancement in performance compared to other methods. plenty of experiments have been done to extend our framework, proving that dlns can be utilized efficiently within this architecture. | arxiv:2404.13941 |
the origin of the asymmetric supernova remnant ( snr ) w49b has been a matter of debate : is it produced by a rare jet - driven core - collapse supernova, or by a normal supernova that is strongly shaped by its dense environment? aiming to uncover the explosion mechanism and origin of the asymmetric, centrally filled x - ray morphology of w49b, we have performed spatially resolved x - ray spectroscopy and a search for potential point sources. we report new candidate point sources inside w49b. the chandra x - ray spectra from w49b are well - characterized by two - temperature gas components ( $ \ sim 0. 27 $ kev + 0. 6 - - 2. 2 kev ). the hot component gas shows a large temperature gradient from the northeast to the southwest and is over - ionized in most regions with recombination timescales of 1 - - $ 10 \ times 10 ^ { 11 } $ cm $ ^ { - 3 } $ s. the fe element shows strong lateral distribution in the snr east, while the distribution of si, s, ar, ca is relatively smooth and nearly axially symmetric. asymmetric type - ia explosion of a chandrasekhar - mass white dwarf well - explains the abundance ratios and metal distribution of w49b, whereas a jet - driven explosion and normal core - collapse models fail to describe the abundance ratios and large masses of iron - group elements. a model based on a multi - spot ignition of the white dwarf can explain the observed high $ m _ { \ rm mn } / m _ { \ rm cr } $ value ( 0. 8 - - 2. 2 ). the bar - like morphology is mainly due to a density enhancement in the center, given the good spatial correlation between gas density and x - ray brightness. the recombination ages and the sedov age consistently suggest a revised snr age of 5 - - 6 kyr. this study suggests that despite the presence of candidate point sources projected within the boundary of this snr, w49b is likely a type - ia snr, which suggests that type - ia supernovae can also result in mixed - morphology snrs. | arxiv:1707.05107 |
this paper is devoted to a nonlinear singular riemann - liouville type fractional differential equation, the local existence of whose continuous solutions under the weakest condition remained as an open problem until now. the singularity of the equation arises from the discontinuity of the right - hand side function $ f ( x, \ omega ) $ at $ x = 0 $, and its order of singularity is the same as the order of the fractional differential operator in the equation. the local existence of solutions to singular equations of such type cannot be established by a direct application of fixed point theorems only or other methods even though they are enough for the same purpose in the case of equations including a singularity of the order less than the order of the corresponding fractional r - l operator. for this reason, we here propose a novel technique with a result for continuous functions to establish a local existence theorem for the problem. moreover, a continuation result is suggested for the local solutions to the problem and, thus, it will be revealed that in what circumstances their existing interval can be extended to larger ones. thanks to this and the proposed technique, the global existence theorem for both sublinear and linear equations is achieved. | arxiv:2103.11797 |
a computational technique for calculating nullity vectors and kernel vectors, using the new finsler package, is introduced. as an application, three interesting counterexamples are given. the first counterexample shows that the two distributions $ \ mathrm { ker } _ r $ and $ \ n _ r $ do not coincide. the second shows that the nullity distribution $ \ n _ { p ^ \ circ } $ is not completely integrable. the third shows that the nullity distribution $ \ n _ \ mathfrak { r } $ is not a sub - distribution of the nullity distribution $ \ n _ { r ^ \ circ } $. | arxiv:1401.0133 |
we study the collapse of a massless scalar field coupled to gravity. a class of blackhole solutions are identified. we also report on a class of solutions where collapse starts from a regular spacelike surface but then the collapsing scalar field freezes. as a result, in these solutions, a black hole does not form, neither is there any singularity in the future. | arxiv:1107.4112 |
dilepton production in in + in collisions at 158 agev is studied within the microscopic parton - hadron - string dynamics ( phsd ) transport approach that incorporates explicit partonic degrees - of - freedom, dynamical hadronization as well as the more familiar hadronic dynamics in the final reaction stages. a comparison to the data of the na60 collaboration shows that the measured dilepton yield is well described by including the collisional broadening of vector mesons, while simultaneously accounting for the electromagnetic radiation of the strongly coupled quark - gluon plasma ( sqgp ) via off - shell quark - antiquark annihilation, quark annihilation with additional gluon bremsstrahlung and the gluon - compton scattering mechanisms. in particular, the spectra in the intermediate mass range ( 1 gev < m < 2. 5 gev ) are dominated by quark - antiquark annihilation in the nonperturbative qgp. also, the observed softening of the transverse mass spectra at intermediate masses ( 1 gev < m < 2. 5 gev ) is approximately reproduced. furthermore, for dileptons of low masses ( m < 0. 6 gev ), we find a sizable contribution from the quark annihilation with additional gluon bremsstrahlung, thus providing another possible window for probing the properties of the sqgp. | arxiv:1107.3402 |
helpfulness prediction techniques have been widely used to identify and recommend high - quality online reviews to customers. currently, the vast majority of studies assume that a review ' s helpfulness is self - contained. in practice, however, customers hardly process reviews independently given the sequential nature. the perceived helpfulness of a review is likely to be affected by its sequential neighbors ( i. e., context ), which has been largely ignored. this paper proposes a new methodology to capture the missing interaction between reviews and their neighbors. the first end - to - end neural architecture is developed for neighbor - aware helpfulness prediction ( nap ). for each review, nap allows for three types of neighbor selection : its preceding, following, and surrounding neighbors. four weighting schemes are designed to learn context clues from the selected neighbors. a review is then contextualized into the learned clues for neighbor - aware helpfulness prediction. nap is evaluated on six domains of real - world online reviews against a series of state - of - the - art baselines. extensive experiments confirm the effectiveness of nap and the influence of sequential neighbors on a current reviews. further hyperparameter analysis reveals three main findings. ( 1 ) on average, eight neighbors treated with uneven importance are engaged for context construction. ( 2 ) the benefit of neighbor - aware prediction mainly results from closer neighbors. ( 3 ) equally considering up to five closest neighbors of a review can usually produce a weaker but tolerable prediction result. | arxiv:2006.09685 |
low physical activity levels in the intensive care units ( icu ) patients have been linked to adverse clinical outcomes. therefore, there is a need for continuous and objective measurement of physical activity in the icu to quantify the association between physical activity and patient outcomes. this measurement would also help clinicians evaluate the efficacy of proposed rehabilitation and physical therapy regimens in improving physical activity. in this study, we examined the feasibility of posture recognition in an icu population using data from wearable sensors. | arxiv:2110.02768 |
we study representations of the loop braid group $ lb _ n $ from the perspective of extending representations of the braid group $ b _ n $. we also pursue a generalization of the braid / hecke / temperlely - lieb paradigm - - - uniform finite dimensional quotient algebras of the loop braid group algebras. | arxiv:1411.3768 |
we show how to systematically derive the complete set of the gauge transformations of different types of the gauge invariant models, which are the chiral schwinger and cp $ ^ 1 $ with chern - simons term, in the lagrangian formalism. | arxiv:hep-th/9810016 |
reinforcement learning ( rl ) methods usually treat reward functions as black boxes. as such, these methods must extensively interact with the environment in order to discover rewards and optimal policies. in most rl applications, however, users have to program the reward function and, hence, there is the opportunity to make the reward function visible - - to show the reward function ' s code to the rl agent so it can exploit the function ' s internal structure to learn optimal policies in a more sample efficient manner. in this paper, we show how to accomplish this idea in two steps. first, we propose reward machines, a type of finite state machine that supports the specification of reward functions while exposing reward function structure. we then describe different methodologies to exploit this structure to support learning, including automated reward shaping, task decomposition, and counterfactual reasoning with off - policy learning. experiments on tabular and continuous domains, across different tasks and rl agents, show the benefits of exploiting reward structure with respect to sample efficiency and the quality of resultant policies. finally, by virtue of being a form of finite state machine, reward machines have the expressive power of a regular language and as such support loops, sequences and conditionals, as well as the expression of temporally extended properties typical of linear temporal logic and non - markovian reward specification. | arxiv:2010.03950 |
the tadpole graph consists of a circle and a half - line attached at a vertex. we analyze standing waves of the nonlinear schr \ " { o } dinger equation with quintic power nonlinearity equipped with the neumann - kirchhoff boundary conditions at the vertex. the profile of the standing wave with the frequency $ \ omega \ in ( - \ infty, 0 ) $ is characterized as a global minimizer of the quadratic part of energy constrained to the unit sphere in $ l ^ 6 $. the set of minimizers includes the set of ground states of the system, which are the global minimizers of the energy at constant mass ( $ l ^ 2 $ - norm ), but it is actually wider. while ground states exist only for a certain interval of masses, the standing waves exist for every $ \ omega \ in ( - \ infty, 0 ) $ and correspond to a bigger interval of masses. it is shown that there exist critical frequencies $ \ omega _ 0 $ and $ \ omega _ 1 $ such that the standing waves are the ground states for $ \ omega \ in [ \ omega _ 0, 0 ) $, local minimizers of the energy at constant mass for $ \ omega \ in ( \ omega _ 1, \ omega _ 0 ) $, and saddle points of the energy at constant mass for $ \ omega \ in ( - \ infty, \ omega _ 1 ) $. proofs make use of both the variational methods and the analytical theory for differential equations. | arxiv:2001.00881 |
we image 104 newly identified low - mass ( mostly m - dwarf ) pre - main sequence members of nearby young moving groups with magellan adaptive optics ( magao ) and identify 27 binaries with instantaneous projected separation as small as 40 mas. 15 were previously unknown. the total number of multiple systems in this sample including spectroscopic and visual binaries from the literature is 36, giving a raw multiplicity rate of at least $ 35 ^ { + 5 } _ { - 4 } \ % $ for this population. in the separation range of roughly 1 - 300 au in which infrared ao imaging is most sensitive, the raw multiplicity rate is at least $ 24 ^ { + 5 } _ { - 4 } \ % $ for binaries resolved by the magao infrared camera ( clio ). the m - star sub - sample of 87 stars yields a raw multiplicity of at least $ 30 ^ { + 5 } _ { - 4 } \ % $ over all separations, $ 21 ^ { + 5 } _ { - 4 } \ % $ for secondary companions resolved by clio from 1 to 300 au ( $ 23 ^ { + 5 } _ { - 4 } \ % $ for all known binaries in this separation range ). a combined analysis with binaries discovered by the search for associations containing young stars shows that multiplicity fraction as a function of mass and age over the range of 0. 2 to 1. 2 $ m _ \ odot $ and 10 - 200 myr appears to be linearly flat in both parameters and across ymgs. this suggests that multiplicity rates are largely set by 100 myr without appreciable evolution thereafter. after bias corrections are applied, the multiplicity fraction of low - mass ymg members ( $ < 0. 6 m _ \ odot $ ) is in excess of the field. | arxiv:1706.07095 |
we determine the capacity of compound classical - quantum channels. as a consequence we obtain the capacity formula for the averaged classical - quantum channels. the capacity result for compound channels demonstrates, as in the classical setting, the existence of reliable universal classical - quantum codes in scenarios where the only a priori information about the channel used for the transmission of information is that it belongs to a given set of memoryless classical - quantum channels. our approach is based on the universal classical approximation of the quantum relative entropy which in turn relies on the universal hypothesis testing results. | arxiv:0710.3027 |
the recent years have witnessed advances in parallel algorithms for large scale optimization problems. notwithstanding demonstrated success, existing algorithms that parallelize over features are usually limited by divergence issues under high parallelism or require data preprocessing to alleviate these problems. in this work, we propose a parallel coordinate descent newton algorithm using multidimensional approximate newton steps ( pcdn ), where the off - diagonal elements of the hessian are set to zero to enable parallelization. it randomly partitions the feature set into $ b $ bundles / subsets with size of $ p $, and sequentially processes each bundle by first computing the descent directions for each feature in parallel and then conducting $ p $ - dimensional line search to obtain the step size. we show that : ( 1 ) pcdn is guaranteed to converge globally despite increasing parallelism ; ( 2 ) pcdn converges to the specified accuracy $ \ epsilon $ within the limited iteration number of $ t _ \ epsilon $, and $ t _ \ epsilon $ decreases with increasing parallelism ( bundle size $ p $ ). using the implementation technique of maintaining intermediate quantities, we minimize the data transfer and synchronization cost of the $ p $ - dimensional line search. for concreteness, the proposed pcdn algorithm is applied to $ \ ell _ 1 $ - regularized logistic regression and $ \ ell _ 2 $ - loss svm. experimental evaluations on six benchmark datasets show that the proposed pcdn algorithm exploits parallelism well and outperforms the state - of - the - art methods in speed without losing accuracy. | arxiv:1306.4080 |
submitted problems to a shortlist. the team leaders arrive at the imo a few days in advance of the contestants and form the imo jury which is responsible for all the formal decisions relating to the contest, starting with selecting the six problems from the shortlist. the jury aims to order the problems so that the order in increasing difficulty is q1, q4, q2, q5, q3 and q6, where the first day problems q1, q2, and q3 are in increasing difficulty, and the second day problems q4, q5, q6 are in increasing difficulty. the team leaders of all countries are given the problems in advance of the contestants, and thus, are kept strictly separated and observed. each country ' s marks are agreed between that country ' s leader and deputy leader and coordinators provided by the host country ( the leader of the team whose country submitted the problem in the case of the marks of the host country ), subject to the decisions of the chief coordinator and ultimately a jury if any disputes cannot be resolved. = = selection process = = the selection process for the imo varies greatly by country. in some countries, especially those in east asia, the selection process involves several tests of a difficulty comparable to the imo itself. the chinese contestants go through a camp. in others, such as the united states, possible participants go through a series of easier standalone competitions that gradually increase in difficulty. in the united states, the tests include the american mathematics competitions, the american invitational mathematics examination, and the united states of america junior mathematical olympiad / united states of america mathematical olympiad, each of which is a competition in its own right. for high scorers in the final competition for the team selection, there also is a summer camp, like that of china. in countries of the former soviet union and other eastern european countries, a team has in the past been chosen several years beforehand, and they are given special training specifically for the event. however, such methods have been discontinued in some countries. = = awards = = the participants are ranked based on their individual scores. medals are awarded to the highest ranked participants ; slightly fewer than half of them receive a medal. the cutoffs ( minimum scores required to receive a gold, silver, or bronze medal respectively ) are then chosen so that the numbers of gold, silver and bronze medals awarded are approximately in the ratios 1 : 2 : 3. participants who do not win a medal but who score 7 points on at least one problem receive an honorable mention. | https://en.wikipedia.org/wiki/International_Mathematical_Olympiad |
as subjective artistic creations, artistic paintings carry emotion of their creators. emotions expressed in paintings and emotion aroused in spectators by paintings are two kinds of emotions that scholars have paid attention to. traditional studies on emotions expressed by paintings are mainly conducted from qualitative perspectives, with neither quantitative output on the emotional values of a painting, nor exploration of trends in the expression of emotion in art history. in this research we threat facial expressions in paintings as an artistic characteristics of art history and employ cognitive computation technology to identify the facial emotions in paintings and to investigate the quantitative measures of paintings from three emotion - related aspects : the spatial and temporal patterns of painting emotions in art history, the gender difference on the emotion of paintings and the color preference associated with emotions. we discovered that the emotion of happiness has a growing trend from ancient to modern times in paintings history, and men and women have different facial expressions patterns along time. as for color preference, artists with different culture backgrounds had similar association preferences between colors and emotions. | arxiv:2102.00407 |
is essentially a non - nuclear technology ; it relies on the use of ionizing radiation which may be generated by accelerators for electrons and conversion into bremsstrahlung, but which may use also gamma - rays from nuclear decay. there is a worldwide industry for processing by ionizing radiation, the majority by number and by processing power using accelerators. food irradiation is only a niche application compared to medical supplies, plastic materials, raw materials, gemstones, cables and wires, etc. = = accidents = = nuclear accidents, because of the powerful forces involved, are often very dangerous. historically, the first incidents involved fatal radiation exposure. marie curie died from aplastic anemia which resulted from her high levels of exposure. two scientists, an american and canadian respectively, harry daghlian and louis slotin, died after mishandling the same plutonium mass. unlike conventional weapons, the intense light, heat, and explosive force is not the only deadly component to a nuclear weapon. approximately half of the deaths from hiroshima and nagasaki died two to five years afterward from radiation exposure. civilian nuclear and radiological accidents primarily involve nuclear power plants. most common are nuclear leaks that expose workers to hazardous material. a nuclear meltdown refers to the more serious hazard of releasing nuclear material into the surrounding environment. the most significant meltdowns occurred at three mile island in pennsylvania and chernobyl in the soviet ukraine. the earthquake and tsunami on march 11, 2011 caused serious damage to three nuclear reactors and a spent fuel storage pond at the fukushima daiichi nuclear power plant in japan. military reactors that experienced similar accidents were windscale in the united kingdom and sl - 1 in the united states. military accidents usually involve the loss or unexpected detonation of nuclear weapons. the castle bravo test in 1954 produced a larger yield than expected, which contaminated nearby islands, a japanese fishing boat ( with one fatality ), and raised concerns about contaminated fish in japan. in the 1950s through 1970s, several nuclear bombs were lost from submarines and aircraft, some of which have never been recovered. the last twenty years have seen a marked decline in such accidents. = = examples of environmental benefits = = proponents of nuclear energy note that annually, nuclear - generated electricity reduces 470 million metric tons of carbon dioxide emissions that would otherwise come from fossil fuels. additionally, the amount of comparatively low waste that nuclear energy does create is safely disposed of by the large scale nuclear energy production facilities or it is repurposed / recycled for other energy uses. proponents of nuclear energy | https://en.wikipedia.org/wiki/Nuclear_technology |
we argue that " question answering with knowledge base " and " question answering over linked data " are currently two instances of the same problem, despite one explicitly declares to deal with linked data. we point out the lack of existing methods to evaluate question answering on datasets which exploit external links to the rest of the cloud or share common schema. to this end, we propose the creation of new evaluation settings to leverage the advantages of the semantic web to achieve ai - complete question answering. | arxiv:2005.03640 |
generalized polyhedral convex optimization problems in locally convex hausdorff topological vector spaces are studied systematically in this paper. we establish solution existence theorems, necessary and sufficient optimality conditions, weak and strong duality theorems. in particular, we show that the dual problem has the same structure as the primal problem, and the strong duality relation holds under three different sets of conditions. | arxiv:1709.10227 |
several propositions were done to provide adapted concurrency control to object - oriented databases. however, most of these proposals miss the fact that considering solely read and write access modes on instances may lead to less parallelism than in relational databases! this paper cope with that issue, and advantages are numerous : ( 1 ) commutativity of methods is determined a priori and automatically by the compiler, without measurable overhead, ( 2 ) run - time checking of commutativity is as efficient as for compatibility, ( 3 ) inverse operations need not be specified for recovery, ( 4 ) this scheme does not preclude more sophisticated approaches, and, last but not least, ( 5 ) relational and object - oriented concurrency control schemes with read and write access modes are subsumed under this proposition. | arxiv:1003.4836 |
the dynamics of electronic tunneling through a disordered 1d chain of finite length is considered. we calculate distributions of the transmission coefficient t, wigner delay time and, $ \ tau _ \ phi $ and the transport time, $ \ tau _ t = t \ tau _ \ phi $. the central bodies of these distributions have a power - law form, what can be understood in terms of the resonant tunneling through localised states. | arxiv:cond-mat/9902335 |
schwarzschild coordinates ( r, t ) fail to describe the region within the event horizon ( eh ), ( r < = 2 m ), of a black hole ( bh ) because the metric coefficients exhibit singularity at r = 2 m, and the radial geodesic of a particle appears to be null ( ds ^ 2 = 0 ) when actually it must be timelike ( ds ^ 2 > 0 ), if, indeed, r _ g = 2 m > 0. thus, both the exterior and the interior regions of bhs are described by singularity free kruskal - szekeres coordinates. however, we show that, in this case too, ds ^ 2 = 0 for r = 2m. and this result can be physically reconciled only if the eh coincides with the central singularity or if the mass of schwarzschild black holes m = 0. this conclusion agrees with the result of our following paper ( astro - ph / 9904163 ) which points out that the oppenheimer - snyder paper showing formation of a bh, too, corresponds to a bh of mass m = 0. it means that schwarzschild singularity and the central singularity are synonymous, and there is no spacetime beneath the eh. hence the concept of ` ` white holes ' ' and ` ` other universes ' ' suggested by the kruskal diagram naturally ceases to exist. we insist that our derivation is straightforward and there is no scope for any ambiguity, any reader may be able to verify it. the proper time for formation of a zero mass bh may be seen to be infinite. therefore at any finite epoch there would not be any bh. on the other hand, there would be such eternally collapsing configurations with arbitrary high but finite surface red - shifts. if accretion onto such collapsing configurations is advection dominated, there would be little radiation output. observationally, such collapsing configurations may be identified as ` ` black holes ' '. | arxiv:astro-ph/9904162 |
we study the effect of any uneven voltage distribution on two close cylindrical conductors with parallel axes that are slightly shifted in the radial and by any length in the axial direction. the investigation is especially motivated by certain precision measurements, such as the satellite test of the equivalence principle ( step ). by energy conservation, the force can be found as the energy gradient in the vector of the shift, which requires determining potential distribution and energy in the gap. the boundary value problem for the potential is solved, and energy is thus found to the second order in the small transverse shift, and to lowest order in the gap to cylinder radius ratio. the energy consists of three parts : the usual capacitor part due to the uniform potential difference, the one coming from the interaction between the voltage patches and the uniform voltage difference, and the energy of patch interaction, entirely independent of the uniform voltage. patch effect forces and torques in the cylindrical configuration are derived and analyzed in the next two parts of this work. | arxiv:1009.3292 |
with the prevalence of video sharing, there are increasing demands for automatic video digestion such as highlight detection. recently, platforms with crowdsourced time - sync video comments have emerged worldwide, providing a good opportunity for highlight detection. however, this task is non - trivial : ( 1 ) time - sync comments often lag behind their corresponding shot ; ( 2 ) time - sync comments are semantically sparse and noisy ; ( 3 ) to determine which shots are highlights is highly subjective. the present paper aims to tackle these challenges by proposing a framework that ( 1 ) uses concept - mapped lexical - chains for lag calibration ; ( 2 ) models video highlights based on comment intensity and combination of emotion and concept concentration of each shot ; ( 3 ) summarize each detected highlight using improved sumbasic with emotion and concept mapping. experiments on large real - world datasets show that our highlight detection method and summarization method both outperform other benchmarks with considerable margins. | arxiv:1708.02210 |
this paper introduces the tulipaprofilefitting. jl package, a tool developed in julia for generating renewable energy profiles that fit a specified capacity factor. it addresses the limitations of naive methods in adjusting existing profiles to match improved technology efficiency, particularly in scenarios lacking detailed weather data or technology specifications. by formulating the problem mathematically, the package provides a computationally efficient solution for creating realistic renewable energy profiles based on existing data. it ensures that the adjusted profiles realistically reflect the improvements in technology efficiency, making it an essential tool for energy modellers in analyzing $ co _ 2 $ - neutral energy systems. | arxiv:2311.15281 |
we study the dynamics of polynomial skew products on c ^ 2. by using suitable weights, we prove the existence of several types of green functions. largely, continuity and plurisubharmonicity follow. moreover, it relates to the dynamics of the rational extensions to weighted projective spaces. | arxiv:1205.1121 |
the origin of neutrino mass is a big unsolved problem of the standard model ( sm ) that motivate us to consider beyond the sm ( bsm ) scenarios where sm - singlet right - handed neutrinos ( rhns ) are introduced to explain the origin of the light neutrino masses through the seesaw mechanism. there is a variety of ways which could lead us to this goal and one of them is a general u $ ( 1 ) $ extension of the sm. in this scenario, three sm - singlet rhns are introduced to cancel the gauge and mixed gauge gravity anomalies. after anomaly cancellation, we notice that the left - and right - handed charged fermions are differently charged under the general u $ ( 1 ) $ gauge group evolving a chiral scenario. after the breaking of the general u $ ( 1 ) $ symmetry, a neutral bsm gauge boson $ ( z ^ \ prime ) $ acquires mass and it is a free parameter. such $ z ^ \ prime $, being lighter than $ 5 $ gev, could be probed at the intensity and lifetime frontiers like faser, faser2, dune, and ilc beam dump experiments. the estimated bounds are needed to be compared with the existing bounds. we find that existing constraints from orsay, nomad, ps191, kek, lsnd, charm experiments, and cosmological scenario like sn1987a can be compared in our case once estimated for chiral scenarios. finally, we compare the parameter spaces showing viable ones that could be probed by faser, faser2, dune, and ilc beam dump experiments and already excluded regions from orsay, nomad, ps191, kek, lsnd, charm, and sn1987a for a chiral scenario. | arxiv:2206.12676 |
we construct a family of monotone and convex $ c ^ 1 $ integro cubic splines under a strictly convex position of the dataset. then, we find an optimal spline by considering its approximation properties. finally, we give some examples to illustrate the convex - preserving properties of these splines. | arxiv:2003.05651 |
in this paper we propose an approximate weak stationarity ( $ aw $ - stationarity ) concept designed to deal with { \ em mathematical programs with cardinality constraints } ( mpcac ), and we proved that it is a legitimate optimality condition independently of any constraint qualification. such a sequential optimality condition improves weaker stationarity conditions, presented in a previous work. many research on sequential optimality conditions has been addressed for nonlinear constrained optimization in the last few years, some works in the context of mpcc and, as far as we know, no sequential optimality condition has been proposed for mpcac problems. we also establish some relationships between our $ aw $ - stationarity and other usual sequential optimality conditions, such as akkt, cakkt and pakkt. we point out that, despite the computational appeal of the sequential optimality conditions, in this work we are not concerned with algorithmic consequences. our aim is purely to discuss theoretical aspects of such conditions for mpcac problems. | arxiv:2008.03158 |
dynamics of symmetric and antisymmetric 2 - solitons and 3 - solitons is studied in the model of the nonlinear dual - core coupler and its pt - symmetric version. regions of the convergence of the injected perturbed symmetric and antisymmetric n - solitons into symmetric and asymmetric quasi - solitons are found. in the pt - symmetric system, with the balanced gain and loss acting in the two cores, borders of the stability against the blowup are identified. notably, in all the cases the stability regions are larger for antisymmetric 2 - soliton inputs than for their symmetric counterparts, on the contrary to previously known results for fundamental solitons ( n = 1 ). dynamical regimes ( switching ) are also studied for the 2 - soliton injected into a single core of the coupler. in particular, a region of splitting of the input into a pair of symmetric solitons is found, which is explained as a manifestation of the resonance between the vibrations of the 2 - soliton and oscillations of energy between the two cores in the coupler. | arxiv:1207.3917 |
dxc technology company is an american multinational information technology ( it ) services and consulting company headquartered in ashburn, virginia. = = history = = dxc technology was founded on april 3, 2017, through a merger between hewlett packard enterprise ’ s enterprise services business unit and computer sciences corporation. the company provided business - to - business it services. it began trading on the new york stock exchange under the symbol dxc. at the time of its creation, dxc technology had revenues of $ 25 billion, with 6, 000 enterprise and public sector clients across 70 countries, managed by around 170, 000 staff. in july 2017, the company started a three - year plan to reduce the number of offices in india from 50 to 26, and reduce headcount by 5. 9 % ( around 10, 000 ) employees. in 2018, dxc split off its us public sector segment to create a new company, perspecta inc. in june 2019, with about 43, 000 employees in india and one of its largest delivery engines for application outsourcing and software development, the company restructured its workforce to meet its new revenue profile. mike salvino, the former accenture chief group executive, was named president and ceo of dxc technology in september 2019. in february 2021, french technology services and consulting firm atos ended talks for a potential acquisition of dxc. atos had proposed for us $ 10 billion including debt for acquisition. as of november 2021, dxc had around 130, 000 employees in over 70 countries in its global innovation and delivery centres ; the largest among them is india, followed by the philippines, central europe, and vietnam. in may 2022, salvino was appointed as the chairman of dxc ' s board, taking over ian read following his retirement in july 2022. in october 2023, dxc was delisted from s & p 500 index, and moved to the s & p smallcap 600 index. in december 2023, it was announced that salvino would no longer be ceo of dxc technology. raul fernandez, who was on the board of directors, was appointed as the president and chief executive officer of dxc technology on 1 february 2024. as of november 2024, dxc employs over 125, 000 in over 70 countries of which over 43, 000 are employed at 12 sites across 7 major cities in india. = = = acquisitions = = = in july 2017, dxc purchased enterprise | https://en.wikipedia.org/wiki/DXC_Technology |
let $ \ a $ be an algebra and let $ f ( x _ 1,..., x _ d ) $ be a multilinear polynomial in noncommuting indeterminates $ x _ i $. we consider the problem of describing linear maps $ \ phi : \ a \ to \ a $ that preserve zeros of $ f $. under certain technical restrictions we solve the problem for general polynomials $ f $ in the case where $ \ a = m _ n ( f ) $. we also consider quite general algebras $ \ a $, but only for specific polynomials $ f $. | arxiv:1204.5215 |
we have previously published the isabelle / hol formalization of a general theory of syntax with bindings. in this companion paper, we instantiate the general theory to the syntax of lambda - calculus and formalize the development leading to several fundamental constructions and results : sound semantic interpretation, the church - rosser and standardization theorems, and higher - order abstract syntax ( hoas ) encoding. for church - rosser and standardization, our work covers both the call - by - name and call - by - value versions of the calculus, following classic papers by takahashi and plotkin. during the formalization, we were able to stay focused on the high - level ideas of the development - - thanks to the arsenal provided by our general theory : a wealth of basic facts about the substitution, swapping and freshness operators, as well as recursive - definition and reasoning principles, including a specialization to semantic interpretation of syntax. | arxiv:2107.11674 |
hybrid organic - inorganic perovskites ( hoips ) have recently emerged as highly promising solution - processable materials for photovoltaic ( pv ) and other optoelectronic devices. hoips represent a broad family of materials with properties highly tuneable by the ions that make up the perovskite structure as well as their multiple combinations. interestingly, recent high - efficiency pv devices using hoips with substantially improved long - term stability have used combinations of different ionic compositions. the structural dynamics of these systems are unique for semiconducting materials and are currently argued to be central to hoips stability and charge - transport properties. here, we studied the impact of ionic composition on phonon speeds of hoips from brillouin spectroscopy experiments and density functional theory calculations for fapbbr $ _ 3 $, mapbbr $ _ 3 $, mapbcl $ _ 3 $, and the mixed halide mapbbr $ _ { 1. 25 } $ cl $ _ { 1. 75 } $. our results show that the acoustic phonon speeds can be strongly modified by ionic composition, which we explain by analysing the lead - halide sublattice in detail. the vibrational properties of hoips are therefore tuneable by using targeted ionic compositions in the perovskite structure. this tuning can be rationalized with non - trivial effects, for example, considering the influence of the shape and dipole moment of organic cations. this has an important implication to further improvements in the stability and charge - transport properties of these systems. | arxiv:1801.03434 |
we make a comprehensive investigation of the observational effect of the inflation consistency relation. we focus on the general single - field inflation model with the consistency relation $ r = - 8c _ s n _ t $, and investigate the observational constraints of sound speed $ c _ s $ by using the seven - year wmap data, the bicep tensor power spectrum data, and the constraints on $ f _ { \ rm nl } ^ { \ rm equil. } $ and $ f _ { \ rm nl } ^ { \ rm orth. } $ from the five - year wmap observations. we find that the constraints on the tensor - to - scalar ratio $ r $ is much tighter if $ c _ s $ is small, since a large tilt $ n _ t $ is strongly constrained by the observations. we obtain $ r < 0. 37, 0. 27 $ and 0. 09 ( $ dn _ s / d \ ln k = 0 $ ) for $ c _ s $ = 1, 0. 1 and 0. 01 models at 95. 4 % confidence level. when taking smaller values of $ c _ s $, the positive correlation between $ r $ and $ n _ s $ also leads to slightly tighter constraint on the upper bound of $ n _ s $, while the running of scalar spectral index $ dn _ s / d \ ln k $ is generally unaffected. for the sound speed $ c _ s $, it is not well constrained if only the cmb power spectrum data is used, while the constraints are obtainable by taking $ f _ { \ rm nl } ^ { \ rm equil. } $ and $ f _ { \ rm nl } ^ { \ rm orth. } $ priors into account. with the constraining data of $ f _ { \ rm nl } ^ { \ rm equil. } $ and $ f _ { \ rm nl } ^ { \ rm orth. } $, we find that, $ c _ s \ lesssim 0. 01 $ region is excluded at 99. 7 % cl, and the $ c _ s = 1 $ case ( the single - field slow - roll inflation ) is slightly disfavored at 68. 3 % cl. in addition, the inclusion of $ f _ { \ rm nl } ^ { \ rm equil. } $ and $ f _ { \ rm nl } ^ { \ rm orth. } $ into | arxiv:1207.6113 |
cross - organisational workflows involve multiple concurrent, collaborative workflows across different departments or organisations, necessitating effective coordination due to their interdependent nature and shared resource requirements. the complexity of designing and managing these workflows stems from the need for comprehensive domain knowledge and a unified understanding of task dependencies and resource allocation. existing tools often fall short in facilitating effective cross - organisational collaboration and resource sharing. this paper introduces easyrpl, a user - friendly web - based tool suite designed to manage cross - organisational workflows. easyrpl consists of a simulator for visualising the impact of workflow changes, a peak resource analysis tool for identifying potential resource bottlenecks, and a time analysis tool for estimating execution time. these tools assist planners with detailed insights to optimise workflow efficiency and minimise disruptions, enhancing the management of complex, interdependent workflows. | arxiv:2502.20972 |
the heisenberg model on a face center cubic ( fcc ) lattice is a typical three - dimensional frustrated spin system expected to have magnetization plateaus and supersolid phases. there are model compounds $ a _ 2 $ coteo $ _ 6 $ ( $ a $ = ca, sr, pb ) for the fcc lattice but with lattice distortions. motivated by the presence of the compounds, we investigate the ground state of the spin - 1 / 2 antiferromagnetic heisenberg model on a tetragonally distorted fcc lattice in the magnetic field using a large - size cluster mean - field method for the sake of finding new supersolid phases. we find five supersolid phases in the model, indicating possibility to observe supersolid phases in these compounds. we also find that one of the supersolid phases is similar to the nonclassical coplanar phase obtained in the xxz model on the triangular lattice. | arxiv:1901.02996 |
the fluorescence yield for dry air and pure nitrogen excited by electrons is calculated using a combination of well - established molecular properties and experimental data of the involved cross sections. particular attention has been paid to the role of secondary electrons from ionization processes. at high pressure and high energy, observed fluorescence turns out to be proportional to the ionization cross section which follows the born - bethe law. predictions on fluorescence yields in a very wide interval of electron energies ( ev - gev ) and pressures ( 1 and 1013 hpa ) as expected from laboratory measurements are presented. experimental results at energies over 1 mev are in very good agreement with our calculations for pure nitrogen while discrepancies of about 20 % are found for dry air, very likely associated to uncertainties in the available data on quenching cross sections. the relationship between fluorescence emission, stopping power and deposited energy is discussed. | arxiv:astro-ph/0604498 |
the aim of this work was to show few examples and few perspective of modeling in epidemiology. we began with differential equations which were a first tool to describe and predict that phenomena. wroclaw as a cite was very important, because statistics from smallpox epidemic were used by bernoulli to estimate parameters of first mathematical model of epidemic. next step were sir models and those also appeared first as differential equations. they were very popular in begin of xx century. when computer simulation changed the world of mathematical modeling agent - based models gave more possibilities in epidemiology. that models have a big privilege on differential equation, because of information of social network people habits and reaction on infections, which can me involved in agent - based models as well as governmental intervention. we showed in this work how that human relations are important in transmitting diseases and there is example, where it is possible to conduct experiments of significant policy relevance ( vaccinating ), such as investigating the initial growth of an epidemic on a real - world network. presented h1n1 model could be observed in real time ( prediction was made in september 2009 for winter season 2009 / 2010 ) what make it more exiting and also practice. | arxiv:1303.7208 |
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