text
stringlengths 1
3.65k
| source
stringlengths 15
79
|
|---|---|
in this short note, we answer two questions of chen and ruzsa negatively and answer a problem of ma and chen affirmatively.
|
arxiv:2208.05774
|
within quantum mechanics model we study the problem of resummation of an asymptotic perturbation series for bound state parameters via optimization of the perturbative expansion. a possible application of the method to the positronium lifetime calculation is also briefly considered.
|
arxiv:hep-ph/9506370
|
the production of a kaon pair ( $ k ^ + k ^ - $ and $ k ^ 0 _ s k ^ 0 _ s $ ) in two - photon processes has been measured using the belle detector at the electron - positron collider kekb. we have obtained the invariant - mass distribution of the processes between 1. 3 and 2. 3 gev. a broad bump structure around 1. 7 gev in the $ k ^ 0 _ s k ^ 0 _ s $ channel is confirmed, while, in the $ k ^ + k ^ - $ channel, a bump structure is seen near 1. 9 gev. the angular distribution of the final - state kaons is analyzed to explore the spin ( - helicity ) structure in each invariant - mass region for the two processes. contributions from existing and postulated resonances are discussed.
|
arxiv:hep-ex/0104024
|
the growth of supermassive black holes ( smbhs ) appears to be closely linked with the formation of spheroids. there is a pressing need to acquire better statistics on smbh masses, since the existing samples are preferentially weighted toward early - type galaxies with very massive smbhs. with this motivation we started a project aimed at measuring upper limits on the mass of the smbhs that can be present in the center of all the nearby galaxies ( d < 100 mpc ) for which stis / g750m spectra are available in the hst archive. these upper limits will be derived by modeling the central emission - line widths ( [ nii ], halpha and [ sii ] ) observed over an aperture of ~ 0. 1 " ( r < 50 pc ). here we present our preliminary results for a subsample of 76 bulges.
|
arxiv:0709.0866
|
the present article concludes that a ferromagnetic sample could be considered like a paramagnetic system where the role of magnetic moments plays magnetic domains. based on this conclusion and taking into account presence of an anisotropic field the formula which describes magnetization dependence on the external magnetic field is derived. expressions for a remanent magnetization and a coercive force are presented. the new parameter to characterize a magnetic stiffness of a material is introduced. a physical expression for a dynamic magnetic susceptibility as a function of material ' s characteristics, external magnetic field, and a temperature is given.
|
arxiv:1506.01805
|
the data center of tomorrow is a data center made up of heterogeneous systems, which will run heterogeneous workloads. the systems will be located as close as possible to the data. heterogeneous systems will be equipped with binary, biological inspired and quantum accelerators. these architectures will be the foundations to address challenges. like an orchestra conductor, the hybrid cloud will make it possible to set these systems to music thanks to a layer of security and intelligent automation.
|
arxiv:2003.10950
|
things mathematical ", although it is plausible that english borrowed only the adjective mathematic ( al ) and formed the noun mathematics anew, after the pattern of physics and metaphysics, inherited from greek. in english, the noun mathematics takes a singular verb. it is often shortened to maths or, in north america, math. = = = ancient = = = in addition to recognizing how to count physical objects, prehistoric peoples may have also known how to count abstract quantities, like time — days, seasons, or years. evidence for more complex mathematics does not appear until around 3000 bc, when the babylonians and egyptians began using arithmetic, algebra, and geometry for taxation and other financial calculations, for building and construction, and for astronomy. the oldest mathematical texts from mesopotamia and egypt are from 2000 to 1800 bc. many early texts mention pythagorean triples and so, by inference, the pythagorean theorem seems to be the most ancient and widespread mathematical concept after basic arithmetic and geometry. it is in babylonian mathematics that elementary arithmetic ( addition, subtraction, multiplication, and division ) first appear in the archaeological record. the babylonians also possessed a place - value system and used a sexagesimal numeral system which is still in use today for measuring angles and time. in the 6th century bc, greek mathematics began to emerge as a distinct discipline and some ancient greeks such as the pythagoreans appeared to have considered it a subject in its own right. around 300 bc, euclid organized mathematical knowledge by way of postulates and first principles, which evolved into the axiomatic method that is used in mathematics today, consisting of definition, axiom, theorem, and proof. his book, elements, is widely considered the most successful and influential textbook of all time. the greatest mathematician of antiquity is often held to be archimedes ( c. 287 – c. 212 bc ) of syracuse. he developed formulas for calculating the surface area and volume of solids of revolution and used the method of exhaustion to calculate the area under the arc of a parabola with the summation of an infinite series, in a manner not too dissimilar from modern calculus. other notable achievements of greek mathematics are conic sections ( apollonius of perga, 3rd century bc ), trigonometry ( hipparchus of nicaea, 2nd century bc ), and the beginnings of algebra ( diophantus, 3rd century ad ). the hindu – arabic numeral system and the rules for
|
https://en.wikipedia.org/wiki/Mathematics
|
we show that a wreath product of two finitely generated abelian groups is lerf. consequently the free metabelian groups are lerf.
|
arxiv:math/0609611
|
graphical calculi are vital tools for representing and reasoning about quantum circuits and processes. some are not only graphically intuitive but also logically complete. the best known of these is the zx - calculus, which is an industry candidate for an intermediate representation ; a language that sits between the algorithm designer ' s intent and the quantum hardware ' s gate instructions. the zx calculus, built from generalised z and x rotations, has difficulty reasoning about arbitrary rotations. this contrasts with the cross - hardware compiler triq which uses these arbitrary rotations to exploit hardware efficiencies. in this paper we introduce the graphical calculus zq, which uses quaternions to represent these arbitrary rotations, similar to triq, and the phase - free z spider to represent entanglement, similar to zx. we show that this calculus is sound and complete for qubit quantum computing, while also showing that a fully spider - based representation would have been impossible. this new calculus extends the zoo of qubit graphical calculi, each with different strengths, and we hope it will provide a common language for the optimisation procedures of both zx and triq.
|
arxiv:2003.09999
|
we propose utilizing n - best reranking to enhance sequence - level knowledge distillation ( kim and rush, 2016 ) where we extract pseudo - labels for student model ' s training data from top n - best hypotheses and leverage a diverse set of models with different inductive biases, objective functions or architectures, including some publicly - available large language models, to pick the highest - quality hypotheses as labels. the effectiveness of our proposal is validated through experiments on the wmt ' 21 german - english and chinese - english translation tasks. our results demonstrate that utilizing pseudo - labels generated by our n - best reranker leads to a significantly more accurate student model. in fact, our best student model achieves comparable accuracy to a large translation model from ( tran et al., 2021 ) with 4. 7 billion parameters, while having two orders of magnitude fewer parameters.
|
arxiv:2305.12057
|
state - of - the - art first principles calculations based on density functional theory were performed on ch _ 3 ( ch _ 2 ) _ { n - 1 } s - au ( 111 ) systems. we show that the adsorption site of methylthiolate at low coverage on the au ( 111 ) surface is the fcc site, not the hcp site as has been recently reported. further, we report results for chain length dependency and the electronic structure of the system.
|
arxiv:cond-mat/0008323
|
given a ( multi ) graph $ g $ which contains a bipartite subgraph with $ \ rho $ edges, what is the largest triangle - free subgraph of $ g $ that can be found efficiently? we present an sdp - based algorithm that finds one with at least $ 0. 8823 \ rho $ edges, thus improving on the subgraph with $ 0. 878 \ rho $ edges obtained by the classic max - cut algorithm of goemans and williamson. on the other hand, by a reduction from hastad ' s 3 - bit pcp we show that it is np - hard to find a triangle - free subgraph with $ ( 25 / 26 + \ epsilon ) \ rho \ approx ( 0. 961 + \ epsilon ) \ rho $ edges. as an application, we classify the maximum promise constraint satisfaction problem maxpcsp ( $ g $, $ h $ ) for all bipartite $ g $ : given an input ( multi ) graph $ x $ which admits a $ g $ - colouring satisfying $ \ rho $ edges, find an $ h $ - colouring of $ x $ that satisfies $ \ rho $ edges. this problem is solvable in polynomial time, apart from trivial cases, if $ h $ contains a triangle, and is np - hard otherwise.
|
arxiv:2406.20069
|
we propose kernel - type smoothed kolmogorov - smirnov and cram \ ' { e } r - von mises tests for data on general interval, using bijective transformations. though not as severe as in the kernel density estimation, utilizing naive kernel method directly to those particular tests will result in boundary problem as well. this happens mostly because the value of the naive kernel distribution function estimator is still larger than $ 0 $ ( or less than $ 1 $ ) when it is evaluated at the boundary points. this situation can increase the errors of the tests especially the second - type error. in this article, we use bijective transformations to eliminate the boundary problem. some simulation results illustrating the estimator and the tests ' performances will be presented in the last part of this article.
|
arxiv:2005.13794
|
the isostaticity theory for stress transmission in macroscopic planar particulate assemblies is extended here to non - rigid particles. it is shown that, provided that the mean coordination number in $ d $ dimensions is $ d + 1 $, macroscopic systems can be mapped onto equivalent assemblies of perectly rigid particles that support the same stress field. the error in the stress field that the compliance introduces for finite systems is shown to decay with size as a power law. this leads to the conclusion that the isostatic state is not limited to infinitely rigid particles both in two and in three dimensions, and paves the way to an application of isostaticity theory to more general systems.
|
arxiv:cond-mat/0501700
|
in this manuscript, we consider the problems of channel assignment in wireless networks and data migration in heterogeneous storage systems. we show that a soft edge coloring approach to both problems gives rigorous approximation guarantees. in the channel assignment problem arising in wireless networks a pair of edges incident to a vertex are said to be conflicting if the channels assigned to them are the same. our goal is to assign channels ( color edges ) so that the number of conflicts is minimized. the problem is np - hard by a reduction from edge coloring and we present two combinatorial algorithms for this case. the first algorithm is based on a distributed greedy method and gives a solution with at most $ 2 ( 1 - \ frac { 1 } { k } ) | e | $ more conflicts than the optimal solution. the approximation ratio if the second algorithm is $ 1 + \ frac { | v | } { | e | } $, which gives a ( $ 1 + o ( 1 ) $ ) - factor for dense graphs and is the best possible unless p = np. we also consider the data migration problem in heterogeneous storage systems. in such systems, data layouts may need to be reconfigured over time for load balancing or in the event of system failure / upgrades. it is critical to migrate data to their target locations as quickly as possible to obtain the best performance of the system. most of the previous results on data migration assume that each storage node can perform only one data transfer at a time. however, storage devices tend to have heterogeneous capabilities as devices may be added over time due to storage demand increase. we develop algorithms to minimize the data migration time. we show that it is possible to find an optimal migration schedule when all $ c _ v $ ' s are even. furthermore, though the problem is np - hard in general, we give an efficient soft edge coloring algorithm that offers a rigorous $ ( 1 + o ( 1 ) ) $ - approximation guarantee.
|
arxiv:1010.4018
|
we approach the strong - coupling thermodynamic limit in the response of the open driven jaynes - cummings ( jc ) oscillator. we do so by highlighting the role of quantum fluctuations against the semiclassical response in three distinct regimes of operation. we begin by demonstrating the persistence of photon blockade, predicted in [ h. j. carmichael, phys. rev. x 5, 031028 ( 2015 ) ], as a manifestation of the inherently - quantum and nonlinear jc spectrum revealed for vanishing dissipation. we then proceed to discuss the importance of bistability, which, despite being present in photon blockade, is able to provide an alignment between the semiclassical nonlinearity and quantum dynamics only for a driving amplitude having the same order of magnitude as the light - matter coupling strength. this resolution brings us to the critical point of the well - known quantum phase transition of second order on resonance, where the quantum and semiclassical pictures are once more contrasted for a varying participation of the two coherent interactions when going through the collapse of the quasi - energy spectrum.
|
arxiv:1908.03754
|
we study the large deviation function for the empirical measure of diffusing particles at one fixed position. we find that the large deviation function exhibits anomalous system size dependence in systems that satisfy the following conditions : ( i ) there exists no macroscopic flow, and ( ii ) their space dimension is one or two. we investigate this anomaly by using a contraction principle. we also analyze the relation between this anomaly and the so - called long - time tail behavior on the basis of phenomenological arguments.
|
arxiv:1303.0391
|
scattering has usually be considered as detrimental for optical focusing or imaging. recently, more and more research has shown that strongly scattering materials can be utilized to focus coherent light by controlling or shaping the incident light. here, purposeful focusing of second - harmonic waves, which are generated and scattered from nonlinear turbid media via feedback - based wavefront shaping is presented. this work shows a flexible manipulation of both disordered linear and nonlinear scattering signals, indicating more controllable degrees of freedom for the description of turbid media. this technique also provides a possible way to an efficient transmission of nonlinear signal at a desired location in the form of a focal point or other patterns. with the combination of random nonlinear optics and wavefront shaping methods, more interesting applications are expected in the future, such as nonlinear transmission matrix, multi - frequency imaging and phase - matching - free nonlinear optics.
|
arxiv:1612.00566
|
we consider the dynamical properties of transcendental entire functions and their compositions. we give several conditions under which fatou set of a transcendental entire function $ f $ coincide with that of $ f \ circ g, $ where $ g $ is another transcendental entire function. we also prove some result giving relationship between singular values of transcendental entire functions and their compositions.
|
arxiv:1307.5785
|
an integrable asymmetric exclusion process with impurities is formulated. the model displays the full spectrum of the stochastic asymmetric xxz chain plus new levels. we derive the bethe equations and calculate the spectral gap for the totally asymmetric diffusion at half filling. while the standard asymmetric exclusion process without impurities belongs to the kpz universality class with a exponent 3 / 2, our model has a scaling exponent 5 / 2.
|
arxiv:1005.3780
|
the near uv spectra of ob stars in our galaxy are often dominated by a very broad extinction band peaking at ~ 2175 angstroms. forty years after its discovery, the origin of this band remains unknown, although interstellar dust particles are generally assumed to be the carriers. here we report that two - photon absorption by hydrogen molecules in gaseous clouds enveloping ob stars can lead to a band peaking at ~ 2175 angstroms. we present astronomical spectral evidence supporting our proposal that this nonlinear absorption mechanism accounts for the lambda2175 feature.
|
arxiv:astro-ph/0608092
|
we propose a simple modification to existing neural machine translation ( nmt ) models that enables using a single universal model to translate between multiple languages while allowing for language specific parameterization, and that can also be used for domain adaptation. our approach requires no changes to the model architecture of a standard nmt system, but instead introduces a new component, the contextual parameter generator ( cpg ), that generates the parameters of the system ( e. g., weights in a neural network ). this parameter generator accepts source and target language embeddings as input, and generates the parameters for the encoder and the decoder, respectively. the rest of the model remains unchanged and is shared across all languages. we show how this simple modification enables the system to use monolingual data for training and also perform zero - shot translation. we further show it is able to surpass state - of - the - art performance for both the iwslt - 15 and iwslt - 17 datasets and that the learned language embeddings are able to uncover interesting relationships between languages.
|
arxiv:1808.08493
|
equilibration times for nuclear matter configurations - - modelling intermediate and high energy nucleus - nucleus collisions - - are evaluated within the semiclassical off - shell transport approach developed recently. the transport equations are solved for a finite box in coordinate space employing periodic boundary conditions. the off - shell transport model is shown to give proper off - shell equilibrium distributions in the limit $ t \ to \ infty $ for the nucleon and $ \ delta $ - resonance spectral functions. we find that equilibration times within the off - shell approach are only slightly enhanced as compared to the on - shell limit for the momentum configurations considered.
|
arxiv:nucl-th/0003002
|
we identify the nonlinear normal modes spawning from the stable equilibrium of a double pendulum under gravity, and we establish their connection to homoclinic orbits through the unstable upright position as energy increases. this result is exploited to devise an efficient swing - up strategy for a double pendulum with weak, saturating actuators. our approach involves stabilizing the system onto periodic orbits associated with the nonlinear modes while gradually injecting energy. since these modes are autonomous system evolutions, the required control effort for stabilization is minimal. even with actuator limitations of less than 1 % of the maximum gravitational torque, the proposed method accomplishes the swing - up of the double pendulum by allowing sufficient time.
|
arxiv:2404.08478
|
in unimodular - like theories, the constants of nature are demoted from pre - given parameters to phase space variables. their canonical duals provide physical time variables. we investigate how this interacts with an alternative approach to varying constants, where they are replaced by dynamical scalar fields. specifically we investigate the brans - dicke theory of gravity and its interaction with clocks dual to the cosmological constant, the planck mass, etc. we crucially distinguish between the different role of newton ' s g in this process, leading to the possibility of local lorentz invariance violation. a large number of possible theories emerge, for example where the brans - dicke coupling, omega, depends on unimodular - like times ( in a generalization of scalar - tensor theories ), or even become the dual variable to unimodular - like clocks ticking variations in other demoted constants, such as the cosmological constant. we scan the space of possible theories and select those most interesting regarding the joint variations of the brans - dicke omega and other parameters, ( such as the cosmological constant ) ; and also regarding their energy conservation violation properties. this ground work is meant to provide the formalism for further developments, namely regarding cosmology, black holes and the cosmological constant problem.
|
arxiv:2312.06602
|
we report experiments on hard sphere colloidal glasses that reveal a type of shear banding hitherto unobserved in soft glasses. we present a scenario that relates this to an instability arising from shear - concentration coupling, a mechanism previously thought unimportant in this class of materials. below a characteristic shear rate $ \ dot \ gamma _ c $ we observe increasingly non - linear velocity profiles and strongly localized flows. we attribute this trend to very slight concentration gradients ( likely to evade direct detection ) arising in the unstable flow regime. a simple model accounts for both the observed increase of $ \ dot \ gamma _ c $ with concentration, and the fluctuations observed in the flow.
|
arxiv:1009.1579
|
we study nonlinear dynamics in a system of two coupled oscillators, describing the motion of two interacting microbubble contrast agents. in the case of identical bubbles, the corresponding symmetry of the governing system of equations leads to the possibility of existence of asymptotically stable synchronous oscillations. however, it may be difficult to create absolutely identical bubbles and, moreover, one can observe in experiments regimes that are unstable with respect to perturbations of equilibrium radii of bubbles. therefore, we investigate the stability of various synchronous and asynchronous dynamical regimes with respect to the breaking of this symmetry. we show that the main factors determining stability or instability of a synchronous attractor are the presence / absence and the type of an asynchronous attractor coexisting with the synchronous attractor. on the other hand, asynchronous hyperchaotic attractors are stable with respect to the symmetry breaking in all the situations we have studied. therefore, they are likely to be observed in physically realistic scenarios and can be beneficial for suitable applications when chaotic behavior is desirable.
|
arxiv:2005.02281
|
magnetic cataclysmic variables are close binary systems containing a strongly magnetized white dwarf that accretes matter coming from an m - dwarf companion. high - energy radiation coming from those objects is emitted from the accretion column close to the white dwarf photosphere at the impact region. its properties depend on the characteristics of the white dwarf and an accurate accretion column model allows the properties of the binary system to be inferred, such as the white dwarf mass, its magnetic field, and the accretion rate. we study the temporal and spectral behaviour of the accretion region and use the tools we developed to accurately connect the simulation results to the x - ray and optical astronomical observations. the radiation hydrodynamics code hades was adapted to simulate this specific accretion phenomena. classical approaches were used to model the radiative losses of the two main radiative processes : bremsstrahlung and cyclotron. the oscillation frequencies and amplitudes in the x - ray and optical domains are studied to compare those numerical results to observational ones. different dimensional formulae were developed to complete the numerical evaluations. the complete characterization of the emitting region is described for the two main radiative regimes : when only the bremsstrahlung losses and when both cyclotron and bremsstrahlung losses are considered. the effect of the non - linear cooling in - stability regime on the accretion column behaviour is analysed. variation in luminosity on short timescales ( ~ 1 s quasi - periodic oscillations ) is an expected consequence of this specific dynamic. the importance of secondary shock instability on the quasi - periodic oscillation phenomenon is discussed. the stabilization effect of the cyclotron process is confirmed by our numerical simulations, as well as the power distribution in the various modes of oscillation.
|
arxiv:1506.05892
|
it was recently discovered that molecular ionization at high x - ray intensity is enhanced, in comparison with that of isolated atoms, through a phenomenon called crexim ( charge - rearrangement - enhanced x - ray ionization of molecules ). x - ray absorption selectively ionizes heavy atoms within molecules, triggering electron transfer from neighboring atoms to the heavy atom sites and enabling further ionization there. the present theoretical study demonstrates that the crexim effect increases with the size of the molecule, as a consequence of increased intramolecular electron transfer from the larger molecular constituents attached to the heavy atoms. we compare x - ray multiphoton ionization dynamics of xenon, iodomethane, and iodobenzene after interacting with an intense x - ray pulse. although their photoionization cross sections are similar, iodomethane and iodobenzene molecules are more ionized than xenon atoms. moreover, we predict that the average total charge of iodobenzene is much larger than that of iodomethane, because of the large number of electrons in the benzene ring. the positive charges transferred from the iodine site to the benzene ring are redistributed such that the higher carbon charges are formed at the far end from the iodine site. our first - principles calculations provide fundamental insights into the interaction of molecules with x - ray free - electron laser ( xfel ) pulses. these insights need to be taken into account for interpreting and designing future xfel experiments.
|
arxiv:1906.02544
|
we propose a novel family of entanglement measures for time - separated subsystems. our definitions are applicable to any quantum system, continuous or discrete. to illustrate their utility, we derive upper and lower bounds on time - separated correlation functions, akin to the bound on spatially separated correlators in terms of the mutual information. in certain cases our bounds are tight. for relativistic quantum field theories our definition agrees with the analytic continuation from spacelike to timelike separated regions. we provide relevant measurement protocols and execute them on the ibm quantum device ibm _ sherbrooke for a simple qubit system. also we perform explicit computations for an ising spin chain, free fermions, ( 1 + 1 ) - dimensional conformal field theories and holographic theories. finally we explain how the proposed entanglement in time provides a microscopic definition for the recently introduced timelike pseudoentropy.
|
arxiv:2502.12240
|
causal networks are often incomplete with missing causal links. this is due to various issues, such as missing observation data. recent approaches to the issue of incomplete causal networks have used knowledge graph link prediction methods to find the missing links. in the causal link a causes b causes c, the influence of a to c is influenced by b which is known as a mediator. existing approaches using knowledge graph link prediction do not consider these mediated causal links. this paper presents hypercausallp, an approach designed to find missing causal links within a causal network with the help of mediator links. the problem of missing links is formulated as a hyper - relational knowledge graph completion. the approach uses a knowledge graph link prediction model trained on a hyper - relational knowledge graph with the mediators. the approach is evaluated on a causal benchmark dataset, clevrer - humans. results show that the inclusion of knowledge about mediators in causal link prediction using hyper - relational knowledge graph improves the performance on an average by 5. 94 % mean reciprocal rank.
|
arxiv:2410.14679
|
the large structures in the outer layer of turbulent wall flows are of great physical importance, because they contain a substantial fraction of the streamwise kinetic energy and of the reynolds stresses. nevertheless, the organization of the outer region of wall turbulence has historically received less attention than that of the inner region, and as a consequence, it is still the subject of many open experimental and theoretical questions. in order to address some of those questions, we have performed direct numerical simulations of the turbulent incompressible flow in plane channels at reynolds numbers 185 - 550. this paper presents some of the results of this simulation, focusing on the statistical description of the size of the large structures of the streamwise velocity and on its scaling with reynolds number.
|
arxiv:1309.2663
|
in this paper, we propose a novel high dimensional constellation design scheme for visible light communication ( vlc ) systems employing red / green / blue light emitting diodes ( rgb leds ). it is in fact a generalized color shift keying ( csk ) scheme which does not suffer efficiency loss due to a constrained sum intensity for all constellation symbols. crucial lighting requirements are included as optimization constraints. to control non - linear distortion, the optical peak - to - average - power ratio ( papr ) of leds is individually constrained. fixing the average optical power, our scheme is able to achieve much lower bit - error rate ( ber ) than conventional schems especially when illumination color is more " unbalanced ". when cross - talks exist among the multiple optical channels, we apply a singular value decomposition ( svd ) - based pre - equalizer and redesign the constellations, and such scheme is shown to outperform post - equalized schemes based on zero - forcing or linear minimum - mean - squared - error ( lmmse ) principles. to further reduce system ber, a binary switching algorithm ( bsa ) is employed the first time for labeling high dimensional constellation. we thus obtains the optimal bits - to - symbols mapping.
|
arxiv:1410.5932
|
the abelian decomposition of qcd reveals two types of gluons : color - neutral ` ` neurons " and color - carrying ` ` chromons ". this classification does not alter the overall properties of qcd, but the investigation of different types of gluon dynamics is necessary. by employing the cho - duan - ge decomposition theorem, we have derived dynamic evolution equations for two types of gluons by using the time - ordered perturbation theory. we propose that the new equations are compatible with the dglap equations, requiring only the separate contributions of neurons and chromons to be summed. surprisingly, with the evolution to high $ q ^ 2 $, the ratio of the number of chromons to neurons is approximately 3 : 1 in small - $ x $ region regardless of the inputs at evolution starting point. the new gluon dynamic equations reevaluate the gluon distribution functions and allow for a elaborate inverstigation of the distinct contributions of gluons in high - energy collisions.
|
arxiv:2401.11442
|
transparent objects are common in daily life, and understanding their multi - layer depth information - - perceiving both the transparent surface and the objects behind it - - is crucial for real - world applications that interact with transparent materials. in this paper, we introduce layereddepth, the first dataset with multi - layer depth annotations, including a real - world benchmark and a synthetic data generator, to support the task of multi - layer depth estimation. our real - world benchmark consists of 1, 500 images from diverse scenes, and evaluating state - of - the - art depth estimation methods on it reveals that they struggle with transparent objects. the synthetic data generator is fully procedural and capable of providing training data for this task with an unlimited variety of objects and scene compositions. using this generator, we create a synthetic dataset with 15, 300 images. baseline models training solely on this synthetic dataset produce good cross - domain multi - layer depth estimation. fine - tuning state - of - the - art single - layer depth models on it substantially improves their performance on transparent objects, with quadruplet accuracy on our benchmark increased from 55. 14 % to 75. 20 %. all images and validation annotations are available under cc0 at https : / / layereddepth. cs. princeton. edu.
|
arxiv:2503.11633
|
geometric models and teichm \ " uller structures have been introduced for the space of smooth expanding circle endomorphisms and for the space of uniformly symmetric circle endomorphisms. the latter one is the completion of the previous one under the techm \ " uller metric. moreover, the spaces of geometric models as well as the teichm \ " uller spaces can be described as the space of h \ " older continuous scaling functions and the space of continuous scaling functions on the dual symbolic space. the characterizations of these scaling functions have been also investigated. the gibbs measure theory and the dual gibbs measure theory for smooth expanding circle dynamics have been viewed from the geometric point of view. however, for uniformly symmetric circle dynamics, an appropriate gibbs measure theory is unavailable, but a dual gibbs type measure theory has been developed for the uniformly symmetric case. this development extends the dual gibbs measure theory for the smooth case from the geometric point of view. in this survey article, we give a review of these developments which combines ideas and techniques from dynamical systems, quasiconformal mapping theory, and teichm \ " uller theory. there is a measure - theoretical version which is called $ g $ - measure theory and which corresponds to the dual geometric gibbs type measure theory. we briefly review it too.
|
arxiv:math/0612578
|
we propose a simple approach for studying systems of compressed matter based on the thomas - fermi statistical model of single atom. the central point of our work is the development of the concept of ` ` statistical ionization ' ' by compression ; in simple terms, we calculate the fraction of electrons within the atom whose positive energy, due to the compression, exceeds the negative binding energy electron - nucleus. next we extend this concept from a single atom to macroscopic systems and write the corresponding equation of state. positive aspects as well as limitations of the model are illustrated and discussed through all the paper.
|
arxiv:cond-mat/0412417
|
we analyse the 3 - extremal holomorphic maps from the unit disc $ \ mathbb { d } $ to the symmetrised bidisc $ \ mathcal { g } $, defined to be the set $ \ { ( z + w, zw ) : z, w \ in \ mathbb { d } \ } $, with a view to the complex geometry and function theory of $ \ mathcal { g } $. these are the maps whose restriction to any triple of distinct points in $ \ mathbb { d } $ yields interpolation data that are only just solvable. we find a large class of such maps ; they are rational of degree at most 4. it is shown that there are two qualitatively different classes of rational $ \ mathcal { g } $ - inner functions of degree at most 4, to be called { \ em aligned } and { \ em caddywhompus } functions ; the distinction relates to the cyclic ordering of certain associated points on the unit circle. the aligned ones are 3 - extremal. we describe a method for the construction of aligned rational $ \ mathcal { g } $ - inner functions ; with the aid of this method we reduce the solution of a 3 - point interpolation problem for aligned holomorphic maps from $ \ mathbb { d } $ to $ \ mathcal { g } $ to a collection of classical nevanlinna - pick problems with mixed interior and boundary interpolation nodes. proofs depend on a form of duality for $ \ mathcal { g } $.
|
arxiv:1307.7081
|
many applications involve the phenomenon of a material absorbing electromagnetic radiation. by exploiting wave interference, the efficiency of absorption can be significantly enhanced. here, we propose friedrich - wintgen bound states in the continuum ( f - w bics ) based on borophene metamaterials to realize coherent perfect absorption with a dual - band absorption peak in commercially important communication bands. the metamaterials consist of borophene gratings and a borophene sheet that can simultaneously support a fabry - perot plasmon resonance and a guided plasmon mode. the formation and dynamic modulation of the f - w bic can be achieved by adjusting the width or carrier density of the borophene grating, while the strong coupling leads to the anti - crossover behavior of the absorption spectrum. due to the weak angular dispersion originating from the intrinsic flat - band characteristic of the deep sub - wavelength periodic structure, the proposed plasmonic system exhibits almost no change in wavelength and absorption at large incident angles ( within 70 degrees ). in addition, we employ the temporal coupled - mode theory including near - and far - field coupling to obtain strong critical coupling, successfully achieve coherent perfect absorption, and can realize the absorption switch by changing the phase difference between the two coherent beams. our findings can offer theoretical support for absorber design and all - optical tuning.
|
arxiv:2312.11999
|
we explore the distribution of rms = sfr / sfr _ ms ( where sfr _ ms is the star formation rate of " main sequence " star - forming galaxies ) for agn hosts at z = 1. we split our sample into two bins of x - ray luminosity divided at lx = 2x10 ^ 43erg s - 1 to investigate whether the rms distribution changes as a function of agn power. our main results suggest that, when the rms distribution of agn hosts is modelled as a log - normal distribution ( i. e. the same shape as that of ms galaxies ), galaxies hosting more powerful x - ray agns ( i. e. lx > 2x10 ^ 43erg s - 1 ) display a narrower rms distribution that is shifted to higher values compared to their lower lx counterparts. in addition, we find that more powerful x - ray agns have sfrs that are more consistent with that of ms galaxies compared to lower lx agns. despite this, the mean sfrs ( as opposed to rms ) measured from these distributions are consistent with the previously observed flat relationship between sfr and lx. our results suggest that the typical star - forming properties of agn hosts change with lx, and that more powerful agns typically reside in more ms - like star - forming galaxies compared to lower lx agns.
|
arxiv:1811.05980
|
programming for a diverse set of compute accelerators in addition to the cpu is a challenge. maintaining separate source code for each architecture would require lots of effort, and development of new algorithms would be daunting if it had to be repeated many times. fortunately there are several portability technologies on the market such as alpaka, kokkos, and sycl. these technologies aim to improve the developer productivity by making it possible to use the same source code for many different architectures. in this paper we use heterogeneous pixel reconstruction code from the cms experiment at the cernl lhc as a realistic use case of a gpu - targeting hep reconstruction software, and report experience from prototyping a portable version of it using kokkos. the development was done in a standalone program that attempts to model many of the complexities of a hep data processing framework such as cmssw. we also compare the achieved event processing throughput to the original cuda code and a cpu version of it.
|
arxiv:2104.06573
|
in this paper, we prove that the symmetric group $ \ mathrm { s } _ n $ has $ 2 ^ { n ^ 2 / 16 + o ( n ^ 2 ) } $ subgroups, settling a conjecture of pyber from 1993. we also derive asymptotically sharp upper and lower bounds on the number of subgroups of $ \ mathrm { s } _ n $ of various kinds, including the number of $ p $ - subgroups. in addition, we prove a range of theorems about random subgroups of $ \ mathrm { s } _ n $. in particular, we prove the surprising result that for infinitely many $ n $, the probability that a random subgroup of $ \ mathrm { s } _ n $ is nilpotent is bounded away from $ 1 $.
|
arxiv:2503.05416
|
hash tables are one of the most fundamental data structures in computer science, in both theory and practice. they are especially useful in external memory, where their query performance approaches the ideal cost of just one disk access. knuth gave an elegant analysis showing that with some simple collision resolution strategies such as linear probing or chaining, the expected average number of disk i / os of a lookup is merely $ 1 + 1 / 2 ^ { \ omega ( b ) } $, where each i / o can read a disk block containing $ b $ items. inserting a new item into the hash table also costs $ 1 + 1 / 2 ^ { \ omega ( b ) } $ i / os, which is again almost the best one can do if the hash table is entirely stored on disk. however, this assumption is unrealistic since any algorithm operating on an external hash table must have some internal memory ( at least $ \ omega ( 1 ) $ blocks ) to work with. the availability of a small internal memory buffer can dramatically reduce the amortized insertion cost to $ o ( 1 ) $ i / os for many external memory data structures. in this paper we study the inherent query - insertion tradeoff of external hash tables in the presence of a memory buffer. in particular, we show that for any constant $ c > 1 $, if the query cost is targeted at $ 1 + o ( 1 / b ^ { c } ) $ i / os, then it is not possible to support insertions in less than $ 1 - o ( 1 / b ^ { \ frac { c - 1 } { 4 } } ) $ i / os amortized, which means that the memory buffer is essentially useless. while if the query cost is relaxed to $ 1 + o ( 1 / b ^ { c } ) $ i / os for any constant $ c < 1 $, there is a simple dynamic hash table with $ o ( 1 ) $ insertion cost. these results also answer the open question recently posed by jensen and pagh.
|
arxiv:0811.3062
|
the integrable time - dependent central potentials that admit linear and quadratic first integrals other than those constructed from the angular momentum are determined. it is shown explicitly that previous answers to this problem are incomplete. the results are applied in order to find the integrable time - dependent oscillators, the integrable time - dependent generalized kepler potentials, a class of integrable binary systems with variable mass, and the integrable yukawa and interatomic potentials with time - dependent parameters. finally, a new class of integrable potentials is integrated and the corresponding wavefunction is determined.
|
arxiv:2111.08624
|
recently, table - top experiments involving massive quantum systems have been proposed to test the interface of quantum theory and gravity. in particular, the crucial point of the debate is whether it is possible to conclude anything on the quantum nature of the gravitational field, provided that two quantum systems become entangled solely due to the gravitational interaction. typically, this question has been addressed by assuming a specific physical theory to describe the gravitational interaction, but no systematic approach to characterise the set of possible gravitational theories which are compatible with the observation of entanglement has been proposed. here, we remedy this by introducing the framework of generalised probabilistic theories ( gpts ) to the study of the nature of the gravitational field. this framework enables us to systematically study all theories compatible with the detection of entanglement generated via the gravitational interaction between two systems. we prove a no - go theorem stating that the following statements are incompatible : i ) gravity is able to generate entanglement ; ii ) gravity mediates the interaction between the systems ; iii ) gravity is classical. we analyse the violation of each condition, in particular with respect to alternative non - linear models such as the schr \ " odinger - newton equation and collapse models.
|
arxiv:2012.01441
|
in this paper we develop a mathematical model combined with machine learning techniques to predict shade - seeking behavior in cows exposed to heat stress. the approach integrates advanced mathematical features, such as time - averaged thermal indices and accumulated heat stress metrics, obtained by mathematical analysis of data from a farm in titaguas ( valencia, spain ), collected during the summer of 2023. two predictive models, random forests and neural networks, are compared for accuracy, robustness, and interpretability. the random forest model is highlighted for its balance between precision and explainability, achieving an rmse of $ 14. 97 $. the methodology also employs $ 5 - $ fold cross - validation to ensure robustness under real - world conditions. this work not only advances the mathematical modeling of animal behavior but also provides useful insights for mitigating heat stress in livestock through data - driven tools.
|
arxiv:2501.05494
|
, animal entrails, dreams, malformed births, or even the color of a dog urinating on a person ) and celestial phenomena. moreover, babylonian astrology was inseparable from babylonian astronomy. = = = = mathematics = = = = the mesopotamian cuneiform tablet plimpton 322, dating to the 18th century bce, records a number of pythagorean triplets ( 3, 4, 5 ) and ( 5, 12, 13 )..., hinting that the ancient mesopotamians might have been aware of the pythagorean theorem over a millennium before pythagoras. = = ancient and medieval south asia and east asia = = mathematical achievements from mesopotamia had some influence on the development of mathematics in india, and there were confirmed transmissions of mathematical ideas between india and china, which were bidirectional. nevertheless, the mathematical and scientific achievements in india and particularly in china occurred largely independently from those of europe and the confirmed early influences that these two civilizations had on the development of science in europe in the pre - modern era were indirect, with mesopotamia and later the islamic world acting as intermediaries. the arrival of modern science, which grew out of the scientific revolution, in india and china and the greater asian region in general can be traced to the scientific activities of jesuit missionaries who were interested in studying the region ' s flora and fauna during the 16th to 17th century. = = = india = = = = = = = mathematics = = = = the earliest traces of mathematical knowledge in the indian subcontinent appear with the indus valley civilisation ( c. 3300 – c. 1300 bce ). the people of this civilization made bricks whose dimensions were in the proportion 4 : 2 : 1, which is favorable for the stability of a brick structure. they also tried to standardize measurement of length to a high degree of accuracy. they designed a ruler — the mohenjo - daro ruler — whose length of approximately 1. 32 in ( 34 mm ) was divided into ten equal parts. bricks manufactured in ancient mohenjo - daro often had dimensions that were integral multiples of this unit of length. the bakhshali manuscript contains problems involving arithmetic, algebra and geometry, including mensuration. the topics covered include fractions, square roots, arithmetic and geometric progressions, solutions of simple equations, simultaneous linear equations, quadratic equations and indeterminate equations of the second degree. in the 3rd century bce, pingala presents the pingala - sutras, the
|
https://en.wikipedia.org/wiki/History_of_science
|
recent observations of type ia supernovae ( sne ia ) suggest that some of the progenitor white dwarfs ( wds ) had masses up to 2. 4 - 2. 8 m _ sun, highly exceeding the chandrasekhar mass limit. we present a new single degenerate ( sd ) model for sn ia progenitors, in which the wd mass possibly reaches 2. 3 - 2. 7 m _ sun. three binary evolution processes are incorporated ; optically thick winds from mass - accreting wds, mass - stripping from the binary companion star by the wd winds, and wds being supported by differential rotation. the wd mass can increase by accretion up to 2. 3 ( 2. 7 ) m _ sun from the initial value of 1. 1 ( 1. 2 ) m _ sun, being consistent with high luminosity sne ia such as sn 2003fg, sn 2006gz, sn 2007if, and sn 2009dc. there are three characteristic mass ranges of exploding wds. in an extreme massive case, differentially rotating wds explode as an sn ia soon after the wd mass exceeds 2. 4 m _ sun because of a secular instability at t / | w | \ sim 0. 14. for a mid mass range of m _ wd = 1. 5 - 2. 4 m _ sun, it takes some time ( spinning - down time ) until carbon is ignited to induce an sn ia explosion after the wd mass has reached maximum, because it needs a loss or redistribution of angular momentum. for a lower mass case of rigidly rotating wds, m _ wd = 1. 38 - 1. 5 m _ sun, the spinning - down time depends on the timescale of angular momentum loss from the wd. the difference in the spinning - down time may produce the " prompt " and " tardy " components. we also suggest the very bright super - chandrasekhar mass sne ia are born in a low metallicity environment.
|
arxiv:1106.3510
|
we examine a broad range of mass flow diagnostics in a large sample of herbig ae / be stars ( haebes ) using high resolution optical spectra. the h - beta and he i 5876 angstrom lines show the highest incidence of p - cygni ( 30 % ) and inverse p - cygni ( 14 % ) morphologies, respectively. the fe ii 4924 angstrom line also shows a large incidence of p - cygni profiles ( 11 % ). we find support for many of the conclusions reached in a study based on the analysis of the he i 10830 angstrom line in a large sample of haebes. namely, haebes exhibit smaller fractions of both blue - shifted absorption ( i. e. mass outflow ) and red - shifted absorption ( i. e. mass infall or accretion ) than their lower mass cousins, the classical t tauri stars ( cttss ). in particular, the optical data supports the conclusion that haebes displaying red - shifted absorption, in general, show maximum red - shifted absorption velocities that are smaller fractions of their stellar escape velocities than is found for cttss. this suggests that haebe accretion flows are originating deeper in the gravitational potentials of their stars than in ctts systems. in addition, we find a lack of inner disk wind signatures in the blue - shifted absorption objects ; only stellar wind signatures are clearly observed. these findings, along with the lack of detected magnetic fields around haebes, support the idea that large magnetospheres are not prevalent around haebes and that accretion flows are instead mediated by significantly smaller magnetospheres with relatively smaller truncation radii ( e. g. 1 - 2 stellar radii ). red - shifted absorption is much more common around herbig ae stars than be stars, suggesting that herbig be stars may accrete via a boundary layer rather than along magnetic field lines.
|
arxiv:1506.07546
|
as a burgeoning technique, out - of - focus electron ptychography offers the potential for rapidly imaging atomic - scale large fields of view ( fov ) using a single diffraction dataset. however, achieving robust out - of - focus ptychographic reconstruction poses a significant challenge due to the inherent scan instabilities of electron microscopes, compounded by the presence of unknown aberrations in the probe - forming lens. in this study, we substantially enhance the robustness of out - of - focus ptychographic reconstruction by extending our previous calibration method ( the fourier method ), which was originally developed for the in - focus scenario. this extended fourier method surpasses existing calibration techniques by providing more reliable and accurate initialization of scan positions and electron probes. additionally, we comprehensively explore and recommend optimized experimental parameters for robust out - of - focus ptychography, includingaperture size and defocus, through extensive simulations. lastly, we conduct a comprehensive comparison between ptychographic reconstructions obtained with focused and defocused electron probes, particularly in the context of low - dose and precise phase imaging, utilizing our calibration method as the basis for evaluation.
|
arxiv:2406.15879
|
denote by $ { \ bf \ dot b } ^ { \ alpha, \ phi } ( \ omega ) $ the orlicz - besov space, where $ \ alpha \ in \ mathbb { r } $, $ \ phi $ is a young function and $ \ omega \ subset \ mathbb { r } ^ n $ is a domain. for $ \ alpha \ in ( - n, 0 ) $ and optimal $ \ phi $, in this paper we characterize domains supporting the imbedding $ { \ bf \ dot b } ^ { \ alpha, \ phi } ( \ omega ) $ into $ l ^ { n / | \ alpha | } ( \ omega ) $ via globally $ n $ - regular domains. this extends the known characterizations for domains supporting the besov imbedding $ { \ bf \ dot b } ^ s _ { pp } ( \ omega ) $ into $ l ^ { np / ( n - sp ) } ( \ omega ) $ with $ s \ in ( 0, 1 ) $ and $ 1 \ le p < n / s $. the proof of the imbedding $ { \ bf \ dot b } ^ { \ alpha, \ phi } ( \ omega ) \ to l ^ { n / | \ alpha | } ( \ omega ) $ in globally $ n $ - regular domains $ \ omega $ relies on a geometric inequality involving $ \ phi $ and $ \ omega $, which extends a known geometric inequality of caffarelli et al.
|
arxiv:1810.03796
|
we have estimated the size of the light - shifts due to parity nonconservation ( pnc ) interactions in different isotopes of ba + and ra + ions based on the work of fortson [ phys. rev. lett. 70, 2383 ( 1993 ) ]. we have used the nuclear spin independent ( nsi ) amplitudes calculated earlier by us [ phys. rev. lett. 96, 163003 ( 2006 ) ; phys. rev. a 78, 050501 ( r ) ( 2008 ) ] and we have employed the third order many - body perturbation theory ( mbpt ( 3 ) ) in this work to estimate the nuclear spin dependent ( nsd ) amplitudes in these ions. ra + is found to be more favourable than ba + for measuring both the nsi and nsd pnc observables.
|
arxiv:1011.0873
|
we study the spectrum of gravitational perturbations around a vacuum de sitter brane in a 5d asymmetric braneworld model, with induced curvature on the brane. this generalises the stealth acceleration model proposed by charmousis, gregory and padilla ( cgp ) which realises the cardassian cosmology in which power law cosmic acceleration can be driven by ordinary matter. whenever the bulk has infinite volume we find that there is always a perturbative ghost propagating on the de sitter brane, in contrast to the minkowski brane case analysed by cgp. we discuss the implication of this ghost for the stealth acceleration model, and identify a limiting case where the ghost decouples as the de sitter curvature vanishes.
|
arxiv:0901.0713
|
the aim of this research is to apply a novel technique based on the embedding method to solve the n * n fuzzy system of linear equations ( fsles ). by using this method, the strong fuzzy number solutions of fsles can be obtained by transforming the n * n fsle to the crisp system. in this paper, ezzati ' s method to solve the fsles is modified and improved. several theorems are proved to show the number of operations for presented method are less than the methods of friedman and ezzati. in order to show the advantages of scheme, two applicable algorithms are presented and several examples are solved by applying them. also, some graphs of obtained results are demonstrated which show the solutions are in the fuzzy form.
|
arxiv:1809.07271
|
we prove a dynamical version of the mordell - lang conjecture for subvarieties of the affine space a ^ g over a p - adic field, endowed with polynomial actions on each coordinate of a ^ g. we use analytic methods similar to the ones employed by skolem, chabauty, and coleman for studying diophantine equations.
|
arxiv:0705.4047
|
active metamaterials are a type of metamaterial with tunable properties enabled by structural reconfigurations. existing active metamaterials often achieve only a limited number of structural reconfigurations upon the application of an external load across the entire structure. here, we propose a selective actuation strategy for inhomogeneous deformations of magneto - mechanical metamaterials, which allows for the integration of multiple elastic wave tuning functionalities into a single metamaterial design. central to this actuation strategy is that a magnetic field is applied to specific unit cells instead of the entire metamaterial, and the unit cell can transform between two geometrically distinct shapes, which exhibit very different mechanical responses to elastic wave excitations. our numerical simulations and experiments demonstrate that the tunable response of the unit cell, coupled with inhomogeneous deformation achieved through selective actuation, unlocks multifunctional capabilities of magneto - mechanical metamaterials such as tunable elastic wave transmittance, elastic waveguide, and vibration isolation. the proposed selective actuation strategy offers a simple but effective way to control the tunable properties and thus enhances the programmability of magneto - mechanical metamaterials, which also expands the application space of magneto - mechanical metamaterials in elastic wave manipulation.
|
arxiv:2409.07635
|
we analyze three - dimensional hydrodynamical simulations of the interaction of jets and the bubbles they inflate with the intra - cluster medium ( icm ), and show that the heating of the icm by mixing hot bubble gas with the icm operates over tens of millions of years, and hence can smooth the sporadic activity of the jets. the inflation process of hot bubbles by propagating jets forms many vortices, and these vortices mix the hot bubble gas with the icm. the mixing, hence the heating of the icm, starts immediately after the jets are launched, but continues for tens of millions of years. we suggest that the smoothing of the active galactic nucleus ( agn ) sporadic activity by the long - lived vortices accounts for the recent finding of a gentle energy coupling between agn heating and the icm.
|
arxiv:1704.07797
|
monte carlo simulations applied to the spin - fermion model for cuprates show the existence of antiferromagnetic spin domains and charge stripes upon doping. the stripes are partially filled, with a filling of approximately 1 / 2 hole per site, and they separate spin domains with a $ \ pi $ phase shift among them. the stripes observed run either along the x or y axes and they are separated by a large energy barrier. no special boundary conditions or external fields are needed to stabilize these structures at low temperatures. when magnetic incommensurate peaks are observed at momentum $ \ pi ( 1, 1 - \ delta ) $ and symmetrical points, charge incommensurate peaks appear at $ ( 0, 2 \ delta ) $ and symmetrical points, as experimentally observed. the strong charge fluctuations responsible for the formation of the stripes also induce a pseudogap in the density of states.
|
arxiv:cond-mat/9908389
|
we generalize the discussion of hep - th / 0509170 to charged black holes. for the two dimensional charged black hole, which is described by an exactly solvable worldsheet theory, a transition from the black hole to the string phase occurs when the hawking temperature of the black hole reaches a limiting value, the temperature of free strings with the same mass and charge. at this point a tachyon winding around euclidean time in the euclidean black hole geometry, which has a non - zero condensate, becomes massless at infinity, and the horizon of the black hole is infinitely smeared. for reissner - nordstrom black holes in d \ ge 4 dimensions, the exact worldsheet cft is not known, but we propose that it has similar properties. we check that the leading order solution is in good agreement with this proposal, and discuss the expected form of \ alpha ' corrections.
|
arxiv:hep-th/0510211
|
automatic segmentation of anatomical landmarks in endoscopic images can provide assistance to doctors and surgeons for diagnosis, treatments or medical training. however, obtaining the annotations required to train commonly used supervised learning methods is a tedious and difficult task, in particular for real images. while ground truth annotations are easier to obtain for synthetic data, models trained on such data often do not generalize well to real data. generative approaches can add realistic texture to it, but face difficulties to maintain the structure of the original scene. the main contribution in this work is a novel image translation model that adds realistic texture to simulated endoscopic images while keeping the key scene layout information. our approach produces realistic images in different endoscopy scenarios. we demonstrate these images can effectively be used to successfully train a model for a challenging end task without any real labeled data. in particular, we demonstrate our approach for the task of fold segmentation in colonoscopy images. folds are key anatomical landmarks that can occlude parts of the colon mucosa and possible polyps. our approach generates realistic images maintaining the shape and location of the original folds, after the image - style - translation, better than existing methods. we run experiments both on a novel simulated dataset for fold segmentation, and real data from the endomapper ( em ) dataset. all our new generated data and new em metadata is being released to facilitate further research, as no public benchmark is currently available for the task of fold segmentation.
|
arxiv:2505.02654
|
the purpose of this note is to establish, in terms of the primary coefficients in the framework of the tridiagonal theory developed by delsarte and genin in the environment of nonnegative definite toeplitz matrices, necessary and sufficient conditions for the monotonicity with respect to a real parameter of zeros of paraorthogonal polynomials on the unit circle. it is also provided tractable sufficient conditions and an application example. these polynomials can be regarded as the characteristic polynomials of any matrix similar to an unitary upper hessenberg matrix with positive subdiagonal elements.
|
arxiv:1706.05709
|
if a graph can be drawn on the torus so that every two independent edges cross an even number of times, then the graph can be embedded on the torus.
|
arxiv:2009.01683
|
the inverse wave scattering problem seeks to estimate a heterogeneous, inaccessible medium, modeled by unknown variable coefficients in wave equations, from transient recordings of waves generated by probing signals. it is a widely studied inverse problem with important applications, that is typically formulated as a nonlinear least squares data fit optimization. for typical measurement setups and band - limited probing signals, the least squares objective function has spurious local minima far and near the true solution, so newton - type optimization methods fail. we introduce a different approach, for electromagnetic inverse wave scattering in lossless, anisotropic media. our reduced order model ( rom ) is an algebraic, discrete time dynamical system derived from maxwell ' s equations with four important properties : ( 1 ) it is data driven, without knowledge of the medium. ( 2 ) the data to rom mapping is nonlinear and yet the rom can be obtained in a non - iterative fashion. ( 3 ) it has a special algebraic structure that captures the causal wave propagation. ( 4 ) the rom interpolates the data on a uniform time grid. we show how to obtain from the rom an estimate of the wave field at inaccessible points inside the unknown medium. the use of this wave is twofold : first, it defines a computationally inexpensive imaging function designed to estimate the support of reflective structures in the medium, modeled by jump discontinuities of the matrix valued dielectric permittivity. second, it gives an objective function for quantitative estimation of the dielectric permittivity, that has better behavior than the least squares data fitting objective function. the methodology introduced in this paper applies to maxwell ' s equations in three dimensions. to avoid high computational costs, we limit the study to a cylindrical domain filled with an orthotropic medium, so the problem becomes two dimensional.
|
arxiv:2403.03844
|
experimental results for identified hadron spectra in aa collisions at rhic are reviewed. jet suppression in central auau collisions at 200 gev is seen in leading meson and baryon spectra at high p _ t. enhanced baryon production at intermediate p _ t ( 2 < p _ t < 5 gev / c ) is related to quark content but not its mass. in d + au collisions cronin enhancement is observed with larger magnitude for baryons than for mesons, but this difference can not explain the baryon - to - meson ratio in au + au collisions. in au + au the observations at 62. 4 gev and 200 gev are very similar, but smaller suppresion of the leading particles is seen at low beam energy, which is evidence for a smooth beam energy dependence of the effect. near and away side jets seen in two - particle correlations are very similar for the leading baryons and mesons.
|
arxiv:nucl-ex/0505013
|
suppose $ \ mathcal { f } $ is a finite family of graphs. we consider the following meta - problem, called $ \ mathcal { f } $ - immersion deletion : given a graph $ g $ and integer $ k $, decide whether the deletion of at most $ k $ edges of $ g $ can result in a graph that does not contain any graph from $ \ mathcal { f } $ as an immersion. this problem is a close relative of the $ \ mathcal { f } $ - minor deletion problem studied by fomin et al. [ focs 2012 ], where one deletes vertices in order to remove all minor models of graphs from $ \ mathcal { f } $. we prove that whenever all graphs from $ \ mathcal { f } $ are connected and at least one graph of $ \ mathcal { f } $ is planar and subcubic, then the $ \ mathcal { f } $ - immersion deletion problem admits : a constant - factor approximation algorithm running in time $ o ( m ^ 3 \ cdot n ^ 3 \ cdot \ log m ) $ ; a linear kernel that can be computed in time $ o ( m ^ 4 \ cdot n ^ 3 \ cdot \ log m ) $ ; and a $ o ( 2 ^ { o ( k ) } + m ^ 4 \ cdot n ^ 3 \ cdot \ log m ) $ - time fixed - parameter algorithm, where $ n, m $ count the vertices and edges of the input graph. these results mirror the findings of fomin et al. [ focs 2012 ], who obtained a similar set of algorithmic results for $ \ mathcal { f } $ - minor deletion, under the assumption that at least one graph from $ \ mathcal { f } $ is planar. an important difference is that we are able to obtain a linear kernel for $ \ mathcal { f } $ - immersion deletion, while the exponent of the kernel of fomin et al. for $ \ mathcal { f } $ - minor deletion depends heavily on the family $ \ mathcal { f } $. in fact, this dependence is unavoidable under plausible complexity assumptions, as proven by giannopoulou et al. [ icalp 2015 ]. this reveals that the kernelization complexity of $ \ mathcal { f } $ - immersion deleti
|
arxiv:1609.07780
|
systems of interacting fermions can give rise to ground states whose correlations become effectively free - fermion - like in the thermodynamic limit, as shown by baxter for a class of integrable models that include the one - dimensional xyz spin - $ \ frac { 1 } { 2 } $ chain. here, we quantitatively analyse this behaviour by establishing the relation between system size and correlation length required for the fermionic gaussianity to emerge. importantly, we demonstrate that this behaviour can be observed through the applicability of wick ' s theorem and thus it is experimentally accessible. to establish the relevance of our results to possible experimental realisations of xyz - related models, we demonstrate that the emergent gaussianity is insensitive to weak variations in the range of interactions, coupling inhomogeneities and local random potentials.
|
arxiv:2107.06906
|
convolutional neural networks ( cnns ) have achieved remarkable segmentation accuracy on benchmark datasets where training and test sets are from the same domain, yet their performance can degrade significantly on unseen domains, which hinders the deployment of cnns in many clinical scenarios. most existing works improve model out - of - domain ( ood ) robustness by collecting multi - domain datasets for training, which is expensive and may not always be feasible due to privacy and logistical issues. in this work, we focus on improving model robustness using a single - domain dataset only. we propose a novel data augmentation framework called maxstyle, which maximizes the effectiveness of style augmentation for model ood performance. it attaches an auxiliary style - augmented image decoder to a segmentation network for robust feature learning and data augmentation. importantly, maxstyle augments data with improved image style diversity and hardness, by expanding the style space with noise and searching for the worst - case style composition of latent features via adversarial training. with extensive experiments on multiple public cardiac and prostate mr datasets, we demonstrate that maxstyle leads to significantly improved out - of - distribution robustness against unseen corruptions as well as common distribution shifts across multiple, different, unseen sites and unknown image sequences under both low - and high - training data settings. the code can be found at https : / / github. com / cherise215 / maxstyle.
|
arxiv:2206.01737
|
the transition to a renewable energy system poses challenges for power grid operation and stability. secondary control is key in restoring the power system to its reference following a disturbance. underestimating the necessary control capacity may require emergency measures, such as load shedding. hence, a solid understanding of the emerging risks and the driving factors of control is needed. in this contribution, we establish an explainable machine learning model for the activation of secondary control power in germany. training gradient boosted trees, we obtain an accurate description of control activation. using shapely additive explanation ( shap ) values, we investigate the dependency between control activation and external features such as the generation mix, forecasting errors, and electricity market data. thereby, our analysis reveals drivers that lead to high reserve requirements in the german power system. our transparent approach, utilizing open data and making machine learning models interpretable, opens new scientific discovery avenues.
|
arxiv:2109.04802
|
this paper extends our previous works arxiv : 1802. 07306 [ math. nt ], arxiv : 1808. 02382 [ math. nt ] on determining the spectrum, in the berkovich sense, of ultrametric linear differential equations. our previous works focused on equations with constant coefficients or over a field of formal power series. in this paper, we investigate the spectrum of $ p $ - adic differential equations at a generic point on a quasi - smooth curve. this analysis allows us to establish a significant connection between the spectrum and the spectral radii of convergence of a differential equation when considering the affine line. furthermore, the spectrum offers a more detailed decomposition compared to robba ' s decomposition based on spectral radii.
|
arxiv:2111.03548
|
a perturbing shell is introduced as a device for studying the excitation of fluid motions in relativistic stellar models. we show that this approach allows a reasonably clean separation of radiation from the shell and from fluid motions in the star, and provides broad flexibility in the location and timescale of perturbations driving the fluid motions. with this model we compare the relativistic and newtonian results for the generation of even parity gravitational waves from constant density models. our results suggest that relativistic effects will not be important in computations of the gravitational emission except possibly in the case of excitation of the neutron star on very short time scales.
|
arxiv:gr-qc/0002077
|
one interesting method of constraining the dense matter equations of state is to measure the advancement of the periastron of the orbit of a binary radio pulsar ( when it belongs to a double neutron star system ). there is a great deal of interest on applicability of this procedure to the double pulsar system psr j0737 - 3039 ( a / b ). although the above method can be applied to psr a in future within some limitations, for psr b this method can not be applied. on the other hand, the study of genesis of psr b might be useful in this connection and its low mass might be an indication that it could be a strange star.
|
arxiv:astro-ph/0610448
|
we study the collective density modes which can affect neutron - star thermodynamics in the baryonic density range between nuclear saturation ( $ \ rho _ 0 $ ) and $ 3 \ rho _ 0 $. in this region, the expected constituents of neutron - star matter are mainly neutrons, protons and electrons ( $ npe $ matter ), under the constraint of beta equilibrium. the elementary excitations of this $ npe $ medium are studied in the rpa framework. we emphasize the effect of coulomb interaction, in particular the electron screening of the proton plasmon mode. for the treatment of the nuclear interaction, we compare two modern skyrme forces and a microscopic approach. the importance of the nucleon effective mass is observed.
|
arxiv:0811.0604
|
this paper is devoted to the study of symplectic manifolds and their connection with hamiltonian dynamical systems. we review some properties and operations on these manifolds and see how they intervene when studying the complete integrability of these systems, with detailed proofs. several explicit calculations for which references are not immediately available are given. these results are exemplified by applications to some hamiltonian dynamical systems.
|
arxiv:1904.01236
|
notions of minimal sufficient causation are incorporated within the directed acyclic graph causal framework. doing so allows for the graphical representation of sufficient causes and minimal sufficient causes on causal directed acyclic graphs while maintaining all of the properties of causal directed acyclic graphs. this in turn provides a clear theoretical link between two major conceptualizations of causality : one counterfactual - based and the other based on a more mechanistic understanding of causation. the theory developed can be used to draw conclusions about the sign of the conditional covariances among variables.
|
arxiv:0906.1720
|
the general goal of this paper is to gather and review several methods from homotopy and combinatorial topology and formal concepts analysis ( fca ) and analyze their connections. fca appears naturally in the problem of combinatorial simplification of simplicial complexes and allows to see a certain duality on a class of simplicial complexes. this duality generalizes poincare duality on cell subdivisions of manifolds. on the other hand, with the notion of a topological formal context, we review the classical proofs of two basic theorems of homotopy topology : alexandrov nerve theorem and quillen - - mccord theorem, which are both important in the applications. a brief overview of the applications of the nerve theorem in brain studies is given. the focus is made on the task of the external stimuli space reconstruction from the activity of place cells. we propose to use the combination of fca and topology in the analysis of neural codes. the lattice of formal concepts of a neural code is homotopy equivalent to the nerve complex, but, moreover, it allows to analyse certain implication relations between collections of neural cells.
|
arxiv:1911.05491
|
we study the approximability of max ones when the number of variable occurrences is bounded by a constant. for conservative constraint languages ( i. e., when the unary relations are included ) we give a complete classification when the number of occurrences is three or more and a partial classification when the bound is two. for the non - conservative case we prove that it is either trivial or equivalent to the corresponding conservative problem under polynomial - time many - one reductions.
|
arxiv:cs/0606057
|
many systems in biology, physics and engineering can be described by systems of ordinary differential equation containing many parameters. when studying the dynamic behavior of these large, nonlinear systems, it is useful to identify and characterize the steady - state solutions as the model parameters vary, a technically challenging problem in a high - dimensional parameter landscape. rather than simply determining the number and stability of steady - states at distinct points in parameter space, we decompose the parameter space into finitely many regions, the steady - state solutions being consistent within each distinct region. from a computational algebraic viewpoint, the boundary of these regions is contained in the discriminant locus. we develop global and local numerical algorithms for constructing the discriminant locus and classifying the parameter landscape. we showcase our numerical approaches by applying them to molecular and cell - network models.
|
arxiv:1604.02623
|
in the framework of the littlest higgs model with t - parity ( lht ), we study the contributions of the t - even and t - odd particles to the branching ratio r _ b. we find that the precision data of r _ b can give strong constraints on the masses of t - odd fermions.
|
arxiv:0908.2572
|
despite the many recent practical and theoretical breakthroughs in computational game theory, equilibrium finding in extensive - form team games remains a significant challenge. while np - hard in the worst case, there are provably efficient algorithms for certain families of team game. in particular, if the game has common external information, also known as a - loss recall - - informally, actions played by non - team members ( i. e., the opposing team or nature ) are either unknown to the entire team, or common knowledge within the team - - then polynomial - time algorithms exist ( kaneko & kline 1995 ). in this paper, we devise a completely new algorithm for solving team games. it uses a tree decomposition of the constraint system representing each team ' s strategy to reduce the number and degree of constraints required for correctness ( tightness of the mathematical program ). our approach has the bags of the tree decomposition correspond to team - public states. our algorithm reduces the problem of solving team games to a linear program with at most $ o ( nw ^ { w + 1 } ) $ nonzero entries in the constraint matrix, where $ n $ is the size of the game tree, $ w $ is a parameter that depends on the amount of uncommon external information, and $ w $ is the treewidth of the tree decomposition. in public - action games, our program size is bounded by the tighter $ 2 ^ { o ( nt ) } n $ for teams of $ n $ players with $ t $ types each. our algorithm is based on a new way to write a custom, concise tree decomposition, and its fast run time does not assume that the decomposition has small treewidth. since our algorithm describes the polytope of correlated strategies directly, we get equilibrium finding in correlated strategies for free - - instead of, say, having to run a double oracle algorithm. we show via experiments on a standard suite of games that our algorithm achieves state - of - the - art performance on all benchmark game classes except one.
|
arxiv:2109.05284
|
we consider fundamental physical constants which are among a few of the most important pieces of information we have learned about nature after its intensive centuries - long studies. we discuss their multifunctional role in modern physics including problems related to the art of measurement, natural and practical units, origin of the constants, their possible calculability and variability etc.
|
arxiv:physics/0506173
|
we introduce open - loop quantum control protocols for characterizing the spectral properties of non - gaussian noise, applicable to both classical and quantum dephasing environments. the basic idea is to engineer a multi - dimensional frequency comb via repetition of suitably designed pulse sequences, through which the desired high - order noise spectra may be related to observable properties of the qubit probe. we prove that access to a high time resolution is key to achieve spectral reconstruction over an extended bandwidth, overcoming limitations of existing schemes. non - gaussian spectroscopy is demonstrated for a classical noise model describing quadratic dephasing at an optimal point, as well as a quantum spin - boson model out of equilibrium. in both cases, we obtain spectral reconstructions that accurately predict the qubit dynamics in the non - gaussian regime.
|
arxiv:1512.01575
|
on the basis of the model that was successfully applied to kc8, rbc8, and csc8 in 1982, we have calculated the superconducting transition temperature tc for cac6 and ybc6 to find that the same model reproduces the observed tc in those compounds as well, indicating that it is a standard model for superconductivity in the graphite intercalation compounds with tc ranging over three orders of magnitude. further enhancement of tc well beyond 10 k is also predicted. the present method for calculating tc from first principles is compared with that in the density functional theory for superconductors, with paying attention to the feature of determining tc without resort to the concept of the coulomb pseudopotential.
|
arxiv:1601.02753
|
the emergence of the concept of a causal fermion system is revisited and further investigated for the vacuum dirac equation in minkowski space. after a brief recap of the dirac equation and its solution space, in order to allow for the effects of a possibly nonstandard structure of spacetime at the planck scale, a regularization by a smooth cutoff in momentum space is introduced, and its properties are discussed. given an ensemble of solutions, we recall the construction of a local correlation function, which realizes spacetime in terms of operators. it is shown in various situations that the local correlation function maps spacetime points to operators of maximal rank and that it is closed and homeomorphic onto its image. it is inferred that the corresponding causal fermion systems are regular and have a smooth manifold structure. the cases considered include a dirac sea vacuum and systems involving a finite number of particles and antiparticles.
|
arxiv:1909.09229
|
aims : we aim to derive the absolute parameters of the components of ad and, al cam, and v338 her, interpret their orbital period changes and discuss their evolutionary status. methods : new and complete multi - filter light curves of the eclipsing binaries ad and, al cam, and v338 her were obtained and analysed with modern methods. using all reliably observed times of minimum light, we examined orbital period irregularities using the least squares method. in addition, we acquired new spectroscopic observations during the secondary eclipses for al cam and v338 her. results : for al cam and v338 her, we derive reliable spectral types for their primary stars. statistical checks of orbital period analysis for all systems are very reassuring in the cases of v338 her and ad and, although less so for al cam. the light - time effect ( lite ) results are checked by inclusion of a third light option in the photometric analyses. light curve solutions provide the means to calculate the absolute parameters of the components of the systems and reliably estimate their present evolutionary status. conclusions : al cam and v338 her are confirmed as classical algols of relatively low mass in similar configurations. unlike al cam, however, v338 her is still transferring matter between its components, raising interest in the determinability of the evolutionary histories of algols. ad and is found to be a detached system in which both close stars are of age ~ 109 yr and is probably a " non - classical " young triple, at an interesting stage of its dynamical evolution.
|
arxiv:1404.2799
|
we give a non - perturbative definition of u ( n ) gauge theory on fuzzy cp ^ 2 as a multi - matrix model. the degrees of freedom are 8 hermitian matrices of finite size, 4 of which are tangential gauge fields and 4 are auxiliary variables. the model depends on a noncommutativity parameter 1 / n, and reduces to the usual u ( n ) yang - mills action on the 4 - dimensional classical cp ^ 2 in the limit n - > \ infty. we explicitly find the monopole solutions, and also certain u ( 2 ) instanton solutions for finite n. the quantization of the model is defined in terms of a path integral, which is manifestly finite. an alternative formulation with constraints is also given, and a scaling limit as r ^ 4 _ \ theta is discussed.
|
arxiv:hep-th/0407089
|
dynamical models described by ordinary differential equations ( odes ) are a fundamental tool in the sciences and engineering. exact reduction aims at producing a lower - dimensional model in which each macro - variable can be directly related to the original variables, and it is thus a natural step towards the model ' s formal analysis and mechanistic understanding. we present an algorithm which, given a polynomial ode model, computes a longest possible chain of exact linear reductions of the model such that each reduction refines the previous one, thus giving a user control of the level of detail preserved by the reduction. this significantly generalizes over the existing approaches which compute only the reduction of the lowest dimension subject to an approach - specific constraint. the algorithm reduces finding exact linear reductions to a question about representations of finite - dimensional algebras. we provide an implementation of the algorithm, demonstrate its performance on a set of benchmarks, and illustrate the applicability via case studies. our implementation is freely available at https : / / github. com / x3042 / exactodereduction. jl
|
arxiv:2301.11653
|
we study the thermodynamics of the vibrational modes of a lattice pinned by impurity disorder in the absence of topological defects ( bragg glass phase ). using a replica variational method we compute the specific heat $ c _ v $ in the quantum regime and find $ c _ v \ propto t ^ 3 $ at low temperatures in dimension three and two. the prefactor is controlled by the pinning length. the non trivial cancellation of the linear term in $ c _ v $ arises from the so - called marginality condition and has important consequences for other mean field models.
|
arxiv:cond-mat/0212300
|
recent high - profile attacks on the internet of things ( iot ) have brought to the forefront the vulnerability of " smart " devices, and have resulted in numerous iot - focused security analyses. many of the attacks had weak device configuration as the root cause. one potential source of rich and definitive information about the configuration of an iot device is the device ' s firmware. however, firmware analysis is complex and automated firmware analyses have thus far been confined to devices with more traditional operating systems such as linux or vxworks. most iot peripherals, due to lacking traditional operating systems and implementing a wide variety of communication technologies, have only been the subject of smaller - scale analyses. peripheral firmware analysis is further complicated by the fact that such firmware files are predominantly available as stripped binaries, without the elf headers and symbol tables that would simplify reverse engineering. in this paper, we present argxtract, an open - source automated static analysis tool, which extracts security - relevant configuration information from stripped iot peripheral firmware. specifically, we focus on binaries that target the arm cortex - m architecture, due to its growing popularity among iot peripherals. argxtract overcomes the challenges associated with stripped cortex - m analysis and is able to retrieve arguments to security - relevant supervisor and function calls, enabling automated bulk analysis of firmware files. we demonstrate this via three real - world case studies. the largest case study covers a dataset of 243 bluetooth low energy binaries targeting nordic semiconductor chipsets, while the other two focus on nordic ant and stmicroelectronics bluenrg binaries. the results reveal widespread lack of security and privacy controls in iot, such as minimal or no protection for data, fixed passkeys and trackable device addresses.
|
arxiv:2105.03135
|
dujmovi \ ' c, joret, micek, morin, ueckerdt and wood [ j. acm 2020 ] proved that for every planar graph $ g $ there is a graph $ h $ with treewidth at most 8 and a path $ p $ such that $ g \ subseteq h \ boxtimes p $. we improve this result by replacing " treewidth at most 8 " by " simple treewidth at most 6 ".
|
arxiv:2108.00198
|
we define the hitting ( or absorbing ) time for the case of continuous quantum walks by measuring the walk at random times, according to a poisson process with measurement rate $ \ lambda $. from this definition we derive an explicit formula for the hitting time, and explore its dependence on the measurement rate. as the measurement rate goes to either 0 or infinity the hitting time diverges ; the first divergence reflects the weakness of the measurement, while the second limit results from the quantum zeno effect. continuous - time quantum walks, like discrete - time quantum walks but unlike classical random walks, can have infinite hitting times. we present several conditions for existence of infinite hitting times, and discuss the connection between infinite hitting times and graph symmetry.
|
arxiv:0803.3446
|
= helpdesk and incident reporting auditing change management auditing disaster recovery and business continuity auditing isae 3402 = = = miscellaneous = = = xbrl assurance = = = irregularities and illegal acts = = = aicpa standard : sas 99 consideration of fraud in a financial statement audit computer fraud case studies = = references = = = = external links = = a career as information systems auditor archived 2007 - 07 - 12 at the wayback machine, by avinash kadam ( network magazine ) federal financial institutions examination council ( ffiec ) the need for caat technology open security architecture - controls and patterns to secure it systems american institute of certified public accountants ( aicpa ) it services library ( itil )
|
https://en.wikipedia.org/wiki/Information_technology_audit
|
the supernova ( sn ) delay - time distribution ( dtd ) - the sn rate versus time that would follow a brief burst of star formation - can shed light on sn progenitors, and on chemical enrichment timescales. previous attempts to recover the dtd have used comparisons of mean sn rates vs. redshift to cosmic star - formation history ( sfh ), or comparison of sn rates among galaxies of different mean ages. we present an approach to recover the sn dtd that avoids such averaging. we compare the sfhs of individual galaxies to the numbers of sne discovered in each galaxy ( generally zero, sometimes one or a few sne ). we apply the method to a subsample of 3505 galaxies, hosting 82 sne ia and 119 core - collapse sne ( cc sne ), from the lick observatory sn search ( loss ), with sfhs reconstructed from sdss spectra. we find a > 2sigma sn ia dtd signal in our shortest - delay, " prompt ", bin at < 420 myr. despite a systematic error, due to the limited aperture of the sdss spectroscopic fibres, which causes some of the prompt signal to leak to the later dtd bins, the data require prompt sne ia at the > 99 % confidence. we further find, at 4sigma, sne ia that are " delayed " by > 2. 4 gyr. thus, the data support the existence of both prompt and delayed sne ia. the time integral over the cc sn dtd is 0. 010 + / - 0. 002 sne per msun, as expected if all stars of mass > 8 msun lead to visible sn explosions. this argues against a minimum mass for cc sne of > 10 msun, and against a significant fraction of massive stars that collapse without exploding. for sne ia, the time - integrated dtd is 0. 0023 + / - 0. 0006 sne per msun formed, most of them with delays < 2. 4 gyr. we show, using simulations, that application of the method to the full existing loss sample, but with complete and unbiased sfh estimates for the survey galaxies, could provide a detailed measurement of the sn ia dtd.
|
arxiv:1002.3056
|
we re - examine a series of archived centimetre radio - continuum observations ( lambda = 16, 6 and 3 cm ) focusing on ngc7793 using the australia telescope compact array. these new images are both very sensitive ( rms = 0. 011 mjy / beam ) and feature reasonably high angular resolution ( down to < 3 " ). using these images, a total of 76 discrete radio sources are identified, of which 57 have been classified. we also studied the radio component of the micro - quasar ngc7793 - s26 which shows two distinct regions of somewhat steep spectral index between - 0. 3 and - 0. 7.
|
arxiv:1407.2653
|
sending money in cryptocurrencies is majorly based on public keys or their hashed forms - - " addresses. " these long random - looking strings are user unfriendly for transferring by other means than via copy - and - paste or qr codes. replacing such strings with identifiers chosen by users themselves would significantly improve usability of cryptocurrencies. such identifiers could be memorable, easier to write on paper or to dictate over phone. main challenge lies in designing a practically usable decentralised system for providing these identifiers. former solutions have been built as centralised systems or come with nonnegligible limitations. our solution is reminiscent of a prevalent e - mail system, which is an already user friendly and desirably decentralised system. it is shown that our approach is directly applicable also to other systems that use long cryptographic identifiers.
|
arxiv:1612.04982
|
due of its polymorphism, mn $ _ 2 $ fesbo $ _ 6 $ can be synthesized at high pressures and temperatures as a ferrimagnetic ilmenite or an antiferromagnetic perovskite. the structural phase transformation is discussed in detail, and magnetic structures are proposed for both phases. the high - pressure mn $ _ 2 $ fesbo $ _ 6 $ polymorph is a rare example of $ a _ 2 b ' b " $ o $ _ 6 $ perovskite with solely mn cations on the $ a $ - site. fe and sb cations are ordered on the $ b $ - sites. theoretical calculations for the perovskite phase suggest a complex magnetic structure, holding an electronic polarization.
|
arxiv:1210.4368
|
a point mass at the center of an ellipsoidal homogeneous fluid is used as a simple model to study the effect of rotation on the shape and external gravitational field of planets and stars. maclaurin ' s analytical result for a homogenous body is generalized to this model. the absence of a third order term in the taylor expansion of the maclaurin function leads to further simple but very accurate analytical results connecting the three observables : oblateness ( $ \ epsilon $ ), gravitational quadrupole ( $ j _ { 2 } $ ), and angular velocity parameter ( $ q $ ). these are compared to observational data for the planets. the moments of inertia of the planets are calculated and compared to published values. the oblateness of the sun is estimated. oscillations near equilibrium are studied within the model.
|
arxiv:astro-ph/0403328
|
we present an innovative method to resum infrared and collinear logarithms appearing in distributions of jet observables in qcd. the method, based on a general master formula with applicability conditions, allows resummations at next - to - leading logarithmic accuracy in an automated way. as a sample application we present resummed results in hadronic dijet events.
|
arxiv:hep-ph/0305163
|
remote sensing ( rs ) applications in the space domain demand machine learning ( ml ) models that are reliable, robust, and quality - assured, making red teaming a vital approach for identifying and exposing potential flaws and biases. since both fields advance independently, there is a notable gap in integrating red teaming strategies into rs. this paper introduces a methodology for examining ml models operating on hyperspectral images within the hyperview challenge, focusing on soil parameters ' estimation. we use post - hoc explanation methods from the explainable ai ( xai ) domain to critically assess the best performing model that won the hyperview challenge and served as an inspiration for the model deployed on board the intuition - 1 hyperspectral mission. our approach effectively red teams the model by pinpointing and validating key shortcomings, constructing a model that achieves comparable performance using just 1 % of the input features and a mere up to 5 % performance loss. additionally, we propose a novel way of visualizing explanations that integrate domain - specific information about hyperspectral bands ( wavelengths ) and data transformations to better suit interpreting models for hyperspectral image analysis.
|
arxiv:2403.08017
|
the multimodal datasets can be leveraged to pre - train large - scale vision - language models by providing cross - modal semantics. current endeavors for determining the usage of datasets mainly focus on single - modal dataset ownership verification through intrusive methods and non - intrusive techniques, while cross - modal approaches remain under - explored. intrusive methods can adapt to multimodal datasets but degrade model accuracy, while non - intrusive methods rely on label - driven decision boundaries that fail to guarantee stable behaviors for verification. to address these issues, we propose a novel prompt - adapted transferable fingerprinting scheme from a training - free perspective, called patfinger, which incorporates the global optimal perturbation ( gop ) and the adaptive prompts to capture dataset - specific distribution characteristics. our scheme utilizes inherent dataset attributes as fingerprints instead of compelling the model to learn triggers. the gop is derived from the sample distribution to maximize embedding drifts between different modalities. subsequently, our patfinger re - aligns the adaptive prompt with gop samples to capture the cross - modal interactions on the carefully crafted surrogate model. this allows the dataset owner to check the usage of datasets by observing specific prediction behaviors linked to the patfinger during retrieval queries. extensive experiments demonstrate the effectiveness of our scheme against unauthorized multimodal dataset usage on various cross - modal retrieval architectures by 30 % over state - of - the - art baselines.
|
arxiv:2504.11509
|
we compute the gluon and ghost propagators of yang - mills theory in linear covariant gauges from the coupled system of dyson - schwinger equations. for small values of the gauge fixing parameter $ \ xi \ sim 0. 1 $, the deviations to the landau gauge already become clearly visible. for the ghost dressing function, this is reflected in a logarithmic infrared suppression. also, the gluon dressing function changes - but only quantitatively - and the gluon propagator remains finite at zero momentum. from the results, a running coupling is extracted.
|
arxiv:1502.04057
|
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.