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using the identification of sections of the galois group of the ground field into the arithmetic fundamental group with neutral fiber functors of the category of finite connections, we define the " packets " in grothendieck ' s section conjecture and show their properties predicted by him.
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arxiv:math/0703877
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close - in extrasolar planets experience extreme tidal interactions with their host stars. this may lead to a reduction of the planetary orbit and a spin - up of stellar rotation. tidal interactions have been computed for a number of extrasolar planets in circular orbits within 0. 06 au, namely for ogle - tr - 56 b. we compare our range of the tidal dissipation value with two dissipation models from sasselov ( 2003 ) and conclude that our choices are equivalent to these models. however, applied to the planet ogle - tr - 56 b, we find in contrast to sasselov ( 2003 ) that this planet will spiral - in toward the host star in a few billion years. we show that the average and maximum value of our range of dissipation are equivalent to the linear and quadratic dissipation models of sasselov ( 2003 ). due to limitations in the observational techniques, we do not see a possibility to distinguish between the two dissipation models as outlined by sasselov ( 2003 ). ogle - tr - 56 b may therefore not serve as a test case for dissipation models. the probable existence of ogle - tr - 3 b at 0. 02 au and the discovery of ogle - tr - 113 b at 0. 023 au and ogle - tr - 132 b at 0. 03 au may also counter sasselovs ( 2003 ) assumption of a pile - up stopping boundary at 0. 04 au.
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arxiv:astro-ph/0408328
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the role of anharmonic effects on the excitation of the double giant dipole resonance is investigated in a simple macroscopic model. perturbation theory is used to find energies and wave functions of the anharmonic ascillator. the cross sections for the electromagnetic excitation of the one - and two - phonon giant dipole resonances in energetic heavy - ion collisions are then evaluated through a semiclassical coupled - channel calculation. it is argued that the variations of the strength of the anharmonic potential should be combined with appropriate changes in the oscillator frequency, in order to keep the giant dipole resonance energy consistent with the experimental value. when this is taken into account, the effects of anharmonicities on the double giant dipole resonance excitation probabilities are small and cannot account for the well - known discrepancy between theory and experiment.
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arxiv:nucl-th/0202041
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similar to the classical internet, the quantum internet will require knowledge regarding link qualities used for purposes such as optimal route selection. this is commonly accomplished by performing link - level tomography with or without purification - - a. k. a. quantum link bootstrapping. meanwhile, the gate selection and the resource ( bell pair ) selection for a task must be coordinated beforehand. this thesis introduces the ruleset - based communication protocol aimed for supporting the autonomous coordination of quantum operations among distant nodes, with minimal classical packet transmission. this thesis also discusses the ruleset - based quantum link bootstrapping protocol, which consists of recurrent purifications and link - level tomography, evaluated over a markov - chain monte - carlo simulation with noisy systems modeled on real world quality hardware. given a 10km meetinthemiddle based two - node system, each with 100 memory qubits ideally connected to the optical fiber, the recurrent single selection - single error purification ( rss - sp ) protocol is capable of improving the fidelity from an average input $ f _ { r } = 0. 675 $ to approximately $ f _ { r } = 0. 865 $. the system gets noisier with longer channels, in which case errors may develop faster than the purification gain. for a noisier system with a longer channel length, the double selection - based purification shows an advantage for improving the fidelity.
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arxiv:1908.10758
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a general variational principle of classical fields with a lagrangian containing the field quantity and its derivatives of up to the n - th order is presented. noether ' s theorem is derived. the generalized hamilton - jacobi ' s equation for the hamilton ' s principal functional is obtained. these results are surprisingly in great harmony with each other. they will be applied to the general relativity in the subsequent articles, especially the generalized noether ' s theorem will be applied to the problem of conservation and non - conservation in curved spacetime..
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arxiv:0805.0366
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in recent years, transfer learning has garnered significant attention in the machine learning community. its ability to leverage knowledge from related studies to improve generalization performance in a target study has made it highly appealing. this paper focuses on investigating the transfer learning problem within the context of nonparametric regression over a reproducing kernel hilbert space. the aim is to bridge the gap between practical effectiveness and theoretical guarantees. we specifically consider two scenarios : one where the transferable sources are known and another where they are unknown. for the known transferable source case, we propose a two - step kernel - based estimator by solely using kernel ridge regression. for the unknown case, we develop a novel method based on an efficient aggregation algorithm, which can automatically detect and alleviate the effects of negative sources. this paper provides the statistical properties of the desired estimators and establishes the minimax optimal rate. through extensive numerical experiments on synthetic data and real examples, we validate our theoretical findings and demonstrate the effectiveness of our proposed method.
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arxiv:2310.13966
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by adapting methods of \ cite { ac } we prove a sharp estimate on the expansion modulus of the gradient of the log of the parabolic kernel to the sch \ " ordinger operator with convex potential, which improves an earlier work of brascamp - lieb. we also include alternate proofs to the improved log - concavity estimate, and to the fundamental gap theorem of andrews - clutterbuck via the elliptic maximum principle. some applications of the estimates are also obtained, including a sharp lower bound on the first eigenvalue.
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arxiv:1107.2351
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we study two different methods to test gaussianity in cmb maps. one of them is based on the partition function and the other on the morphology of hot and cold spots. the partition function contains information on all the moments and scales, being a useful quantity to compress the large data sets expected from future space missions like planck. in particular, it contains much richer information than the one available through the radiation power spectrum. the second method utilizes morphological properties of hot and cold spots such as the eccentricity and number of spots in cmb maps. we study the performance of both methods in detecting non - gaussian features in small scale cmb simulated maps as those which will be provided by the planck mission.
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arxiv:astro-ph/0010330
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in this article we address the question whether it is possible to learn the differential equations describing the physical properties of a dynamical system, subject to non - conservative forces, from observations of its realspace trajectory ( ies ) only. we introduce a network that incorporates a difference approximation for the second order derivative in terms of residual connections between convolutional blocks, whose shared weights represent the coefficients of a second order ordinary differential equation. we further combine this solver - like architecture with a convolutional network, capable of learning the relation between trajectories of coupled oscillators and therefore allows us to make a stable forecast even if the system is only partially observed. we optimize this map together with the solver network, while sharing their weights, to form a powerful framework capable of learning the complex physical properties of a dissipative dynamical system.
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arxiv:2010.11270
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the $ \ mathbb { r } $ - motivic cohomology of an $ \ mathbb { r } $ - motivic spectrum is a module over the $ \ mathbb { r } $ - motivic steenrod algebra $ \ mathcal { a } ^ { \ mathbb { r } } $. in this paper, we describe how to recover the $ \ mathbb { r } $ - motivic cohomology of the spanier - whitehead dual $ \ mathrm { dx } $ of an $ \ mathbb { r } $ - motivic finite complex $ \ mathrm { x } $, as an $ \ mathcal { a } ^ { \ mathbb { r } } $ - module, given the $ \ mathcal { a } ^ { \ mathbb { r } } $ - module structure on the cohomology of $ \ mathrm { x } $. as an application, we show that 16 out of 128 different $ \ mathcal { a } ^ { \ mathbb { r } } $ - module structures on $ \ mathcal { a } ^ { \ mathbb { r } } ( 1 ) : = \ langle \ mathrm { sq } ^ 1, \ mathrm { sq } ^ 2 \ rangle $ are self - dual.
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arxiv:2309.16142
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we show from covariant transport theory that, for a massless ideal gas equation of state, even a small shear viscosity to entropy density ratio $ \ eta \ approx s / ( 4 \ pi ) $ generates significant 15 - 30 % dissipative corrections to elliptic flow for conditions expected in mid - peripheral ( b = 8 fm ) au + au collisions at $ \ sqrt { s _ { nn } } \ sim 200 $ gev at rhic.
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arxiv:0806.0026
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previous models of galactic disk heating in interactions invoke restrictive assumptions not necessarily valid in modern lcdm contexts : that satellites and orbits are rigid and circular, with slow decay over many orbital times from dynamical friction. this leads to a linear scaling of disk heating with satellite mass : disk heights and velocity dispersions scale ~ m _ sat / m _ disk. in turn, observed disk thicknesses present strong constraints on merger histories : the implication for the milky way is that < 5 % of its mass could come from mergers since z ~ 2, in conflict with cosmological predictions. more realistically, satellites merge on nearly radial orbits, and once near the disk, resonant interactions efficiently remove angular momentum while tidal effects strip mass, leading to rapid merger / destruction in a couple of free - fall plunges. under these conditions the proper heating efficiency is non - linear in mass ratio, ~ ( m _ sat / m _ disk ) ^ 2. we derive the scaling of disk scale heights and velocity dispersions as a function of mass ratio and disk gas content in this regime, and show this accurately describes the results of simulations with proper ' live ' halos and disks. under realistic circumstances, disk heating in minor mergers is suppressed by an order of magnitude relative to expectations of previous models. we show that the milky way disk could have absorbed ~ 5 - 10 1 : 10 mass - ratio mergers since z = 2, in agreement with cosmological models. these distinctions lead to dramatic differences in which mass ratios are most important for disk heating and in the isophotal shapes of disk + bulge systems.
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arxiv:0806.2861
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recently, we have proposed a { \ em euler - lagrange transformation } for cellular automata ( ca ) by developing new transformation formulas. applying this method to the burgers ca ( bca ), we have succeeded in obtaining the lagrange representation of the bca. in this paper, we apply this method to multi - value generalized burgers ca ( gbca ) which include the fukui - ishibashi model and the quick - start model associated with traffic flow. as a result, we have succeeded in clarifying the euler - lagrange correspondence of these models. it turns out, moreover that the gbca can naturally be considered as a simple model of a multi - lane traffic flow.
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arxiv:nlin/0311057
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metabolism unfolds within specific organelles in eukaryotic cells. lysosomes are highly metabolically active organelles, and their metabolic states dynamically influence signal transduction, cellular homeostasis, and organismal physiopathology. despite the significance of lysosomal metabolism, a method for its in vivo measurement is currently lacking. here, we report optical boxcar - enhanced, fluorescence - detected mid - infrared photothermal microscopy, together with ai - assisted data denoising and spectral deconvolution, to map metabolic activity and composition of individual lysosomes in living cells and organisms. using this method, we uncovered lipolysis and proteolysis heterogeneity across lysosomes within the same cell, as well as early - onset lysosomal dysfunction during organismal aging. additionally, we discovered organelle - level metabolic changes associated with diverse lysosomal storage diseases. this method holds the broad potential to profile metabolic fingerprints of individual organelles within their native context and quantitatively assess their dynamic changes under different physiological and pathological conditions, providing a high - resolution chemical cellular atlas.
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arxiv:2504.04305
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we investigate the reconstruction of a fermi surface, which is called a lifshitz transition, in magnetically ordered phases of the periodic anderson model on a square lattice with a finite coulomb interaction between f electrons. we apply the variational monte carlo method to the model by using the gutzwiller wavefunctions for the paramagnetic, antiferromagnetic, ferromagnetic, and charge - density - wave states. we find that an antiferromagnetic phase is realized around half - filling and a ferromagnetic phase is realized when the system is far away from half - filling. in both magnetic phases, lifshitz transitions take place. by analyzing the electronic states, we conclude that the lifshitz transitions to large ordered - moment states can be regarded as itinerant - localized transitions of the f electrons.
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arxiv:1507.04067
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deep neural network ( dnn ) classifiers are powerful tools that drive a broad spectrum of important applications, from image recognition to autonomous vehicles. unfortunately, dnns are known to be vulnerable to adversarial attacks that affect virtually all state - of - the - art models. these attacks make small imperceptible modifications to inputs that are sufficient to induce the dnns to produce the wrong classification. in this paper we propose a novel, lightweight adversarial correction and / or detection mechanism for image classifiers that relies on undervolting ( running a chip at a voltage that is slightly below its safe margin ). we propose using controlled undervolting of the chip running the inference process in order to introduce a limited number of compute errors. we show that these errors disrupt the adversarial input in a way that can be used either to correct the classification or detect the input as adversarial. we evaluate the proposed solution in an fpga design and through software simulation. we evaluate 10 attacks and show average detection rates of 77 % and 90 % on two popular dnns.
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arxiv:2107.09804
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the set of space - time short - distance structures which can be described through linear operators is limited to a few basic cases. these are continua, lattices and a further short - distance structure which implies an ultraviolet cut - off. under certain conditions, these cut - off degrees of freedom can reappear as internal degrees of freedom. we review the current status of the classification and present new conjectures.
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arxiv:hep-th/9810215
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systems of equations are invariant under " polydimensional transformations " which reshuffle the geometry such that what is a line or a plane is dependent upon the frame of reference. this leads us to propose an extension of clifford calculus in which each geometric element ( vector, bivector ) has its own coordinate. a new classical action principle is proposed in which particles take paths which minimize the distance traveled plus area swept out by the spin. this leads to a solution of the 50 year old conundrum of ` what is the correct lagrangian ' in which to derive the papapetrou equations of motion for spinning particles in curved space ( including torsion ). based on talk given at : 5th international conference on clifford algebras and their applications in mathematical physics, ixtapa - zihuatanejo, mexico, june 27 - july 4, 1999.
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arxiv:gr-qc/9909071
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we extend the recent result of t. tao to wave maps defined from the minkowski space of dimension > 4 to a target riemannian manifold which possesses a ` ` bounded parallelizable ' ' structure. this is the case of lie groups, homogeneous spaces as well as the hyperbolic spaces. general compact riemannian manifolds can be imbedded as totally geodesic submanifolds in bounded parallelizable manifolds, and therefore are also covered, in principle, by our result. compactness of the target manifold, which seemed to play an important role in tao ' s result, turns out however to play no role in our discussion. our proof follows closely that of tao ' s recent paper and is based, in particular, on its remarkable microlocal gauge renormalization idea.
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arxiv:math/0012034
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although convergence of the parareal and multigrid - reduction - in - time ( mgrit ) parallel - in - time algorithms is well studied, results on their optimality is limited. appealling to recently derived tight bounds of two - level parareal and mgrit convergence, this paper proves ( or disproves ) $ h _ x $ - and $ h _ t $ - independent convergence of two - level parareal and mgrit, for linear problems of the form $ \ mathbf { u } ' ( t ) + \ mathcal { l } \ mathbf { u } ( t ) = f ( t ) $, where $ \ mathcal { l } $ is symmetric positive definite and runge - kutta time integration is used. the theory presented in this paper also encompasses analysis of some modified parareal algorithms, such as the $ \ theta $ - parareal method, and shows that not all runge - kutta schemes are equal from the perspective of parallel - in - time. some schemes, particularly l - stable methods, offer significantly better convergence than others as they are guaranteed to converge rapidly at both limits of small and large $ h _ t \ xi $, where $ \ xi $ denotes an eigenvalue of $ \ mathcal { l } $ and $ h _ t $ time - step size. on the other hand, some schemes do not obtain $ h $ - optimal convergence, and two - level convergence is restricted to certain regimes. in certain cases, an $ \ mathcal { o } ( 1 ) $ factor change in time step $ h _ t $ or coarsening factor $ k $ can be the difference between convergence factors $ \ rho \ approx0. 02 $ and divergence! the analysis is extended to skew symmetric operators as well, which cannot obtain $ h $ - independent convergence and, in fact, will generally not converge for a sufficiently large number of time steps. numerical results confirm the analysis in practice and emphasize the importance of a priori analysis in choosing an effective coarse - grid scheme and coarsening factor. a mathematica notebook to perform a priori two - grid analysis is available at https : / / github. com / xbraid / xbraid - convergence - est.
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arxiv:1906.06672
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in this paper we model the emission from a relativistically expanding electron - positron pair plasma fireball originating near the surface of a heated neutron star. this pair fireball is deposited via the annihilation of neutrino pairs emanating from the surface of the hot neutron star. the heating of neutron stars may occur in close neutron star binary systems near their last stable orbit. we model the relativistic expansion and subsequent emission of the plasma and find 10 ^ 51 to 10 ^ 52 ergs in gamma - rays are produced with spectral and temporal properties consistent with observed gamma - ray bursts.
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arxiv:astro-ph/0001396
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we explore the four - dimensional effective $ f ( t ) $ gravity with $ t $ the torsion scalar in teleparallelism originating from higher - dimensional space - time theories, in particular the kaluza - klein ( kk ) and randall - sundrum ( rs ) theories. first, through the kk dimensional reduction from the five - dimensional space - time, we obtain the four - dimensional effective theory of $ f ( t ) $ gravity with its coupling to a scalar field. second, taking the rs type - ii model in which there exist the five - dimensional anti - de sitter ( ads ) space - time with four - dimensional friedmann - lema \ ^ { i } tre - robertson - walker ( flrw ) brane, we find that there will appear the contribution of $ f ( t ) $ gravity on the four - dimensional flrw brane. it is demonstrated that inflation and the dark energy dominated stage can be realized in the kk and rs models, respectively, due to the effect of only the torsion in teleparallelism without that of the curvature.
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arxiv:1304.6191
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estimation using pooled sampling has long been an area of interest in the group testing literature. such research has focused primarily on the assumed use of fixed sampling plans ( i ), although some recent papers have suggested alternative sequential designs that sample until a predetermined number of positive tests ( ii ). one major consideration, including in the new work on sequential plans, is the construction of debiased estimators which either reduce or keep the mean square error from inflating. whether, however, under the above or other sampling designs unbiased estimation is in fact possible has yet to be established in the literature. in this paper, we introduce a design which samples until a fixed number of negatives ( iii ), and show that an unbiased estimator exists under this model, while unbiased estimation is not possible for either of the preceding designs ( i ) and ( ii ). we present new estimators under the different sampling plans that are either unbiased or that have reduced bias relative to those already in use as well as generally improve on the mean square error. numerical studies are done in order to compare designs in terms of bias and mean square error under practical situations with small and medium sample sizes.
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arxiv:1608.02241
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distributed decision problems features a group of agents that can only communicate over a peer - to - peer network, without a central memory. in applications such as network control and data ranking, each agent is only affected by a small portion of the decision vector : this sparsity is typically ignored in distributed algorithms, while it could be leveraged to improve efficiency and scalability. to address this issue, our recent paper introduces estimation network design ( end ), a graph theoretical language for the analysis and design of distributed iterations. end algorithms can be tuned to exploit the sparsity of specific problem instances, reducing communication overhead and minimizing redundancy, yet without requiring case - by - case convergence analysis. in this paper, we showcase the flexility of end in the context of distributed optimization. in particular, we study the sparsity - aware version of many established methods, including admm, augdgm and push - sum dgd. simulations on an estimation problem in sensor networks demonstrate that end algorithms can boost convergence speed and greatly reduce the communication and memory cost.
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arxiv:2404.15273
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in this series of papers we show that there are exactly ten subfactors, other than $ a _ \ infty $ subfactors, of index between 4 and 5. previously this classification was known up to index $ 3 + \ sqrt { 3 } $. in the first paper we give an analogue of haagerup ' s initial classification of subfactors of index less than $ 3 + \ sqrt { 3 } $, showing that any subfactor of index less than 5 must appear in one of a large list of families. these families will be considered separately in the three subsequent papers in this series.
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arxiv:1007.1730
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this note proposes a new proof and new perspectives on the so - called elliptical potential lemma. this result is important in online learning, especially for linear stochastic bandits. the original proof of the result, however short and elegant, does not give much flexibility on the type of potentials considered and we believe that this new interpretation can be of interest for future research in this field.
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arxiv:2010.10182
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text - to - image generation has recently witnessed remarkable achievements. we introduce a text - conditional image diffusion model, termed raphael, to generate highly artistic images, which accurately portray the text prompts, encompassing multiple nouns, adjectives, and verbs. this is achieved by stacking tens of mixture - of - experts ( moes ) layers, i. e., space - moe and time - moe layers, enabling billions of diffusion paths ( routes ) from the network input to the output. each path intuitively functions as a " painter " for depicting a particular textual concept onto a specified image region at a diffusion timestep. comprehensive experiments reveal that raphael outperforms recent cutting - edge models, such as stable diffusion, ernie - vilg 2. 0, deepfloyd, and dall - e 2, in terms of both image quality and aesthetic appeal. firstly, raphael exhibits superior performance in switching images across diverse styles, such as japanese comics, realism, cyberpunk, and ink illustration. secondly, a single model with three billion parameters, trained on 1, 000 a100 gpus for two months, achieves a state - of - the - art zero - shot fid score of 6. 61 on the coco dataset. furthermore, raphael significantly surpasses its counterparts in human evaluation on the vilg - 300 benchmark. we believe that raphael holds the potential to propel the frontiers of image generation research in both academia and industry, paving the way for future breakthroughs in this rapidly evolving field. more details can be found on a webpage : https : / / raphael - painter. github. io /.
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arxiv:2305.18295
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a possible origin of khz qpos in low - mass x - ray binaries is proposed. recent numerical mhd simulations of accretion disks with turbulent magnetic fields of mri definitely show the presence of two - armed spiral structure in quasi - steady state of accretion disks. in such deformed disks, two - armed ( $ m = 2 $ ) c - mode ( $ n = 1 $ ) oscillations are excited by wave - wave resonant instability. among these excited oscillations, the fundamental in the radial direction ( $ n _ r = 0 $ ) will be the higher khz qpo of a twin qpos, and the first overtone ( $ n _ r = 1 $ ) in the radial direction will be the lower khz qpo of the twin. a possible cause of the twin high - frequency qpos ( hfqpos ) in bh x - ray binaries is also discussed.
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arxiv:2002.10630
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this pedagogical review presents the shell correction method ( scm ) and variants thereof, appropriate for describing shape deformations and electronic shell effects, energetics and decay pathways of metal - cluster fragmentation processes ( e. g., monomer / dimer dissociation and fission ). the experimental trends are compared to the theoretical scm interpretations, and in addition theoretical results for fission from first - principles molecular - dynamics simulations are discussed. some latest insights concerning the importance of electronic - entropy and finite - temperature effects are given special attention.
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arxiv:physics/9909022
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two - and three - particle distribution amplitudes of heavy pseudoscalar mesons of well - defined geometric twist are introduced. they are obtained from appropriately parametrized vacuum - to - meson matrix elements by applying those twist projectors which determine the enclosed light - cone operators of definite geometric twist and, in addition, observing the heavy quark constraint. comparing these distribution amplitudes with the conventional ones of dynamical twist we derive relations between them, partially being of wandzura - wilczek type ; also sum rules of burkhardt - cottingham type are derived. the derivation is performed for the ( double ) mellin moments and then re - summed to the non - local distribution amplitudes. furthermore, a parametrization of vacuum - to - meson matrix elements for non - local operators off the light - cone in terms of distribution amplitudes accompanying independent kinematical structures is derived.
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arxiv:hep-ph/0502239
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atlas found that none of their standard model simulations can describe the measured differential lepton distributions in their $ t \ bar { t } $ analysis reasonably well. therefore, we study the possibility that this measurement has a new physics contamination. we consider a benchmark model motivated by the indications for di - photon resonances : a heavy scalar decays into two lighter higgs bosons with masses of 152 \, gev and 95 \, gev, with subsequent decay to $ ww $ and $ bb $, respectively. in this setup, the description of data is improved by at least $ 5. 6 \ sigma $.
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arxiv:2312.01458
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science fiction community between a trend of increasingly diverse works and authors being honored by awards, and reaction by groups of authors and fans who preferred what they considered more " traditional " science fiction. = = = awards = = = among the most significant and well - known awards for science fiction are the hugo award for literature, presented by the world science fiction society at worldcon, and voted on by fans ; the nebula award for literature, presented by the science fiction and fantasy writers of america, and voted on by the community of authors ; the john w. campbell memorial award for best science fiction novel, presented by a jury of writers ; and the theodore sturgeon memorial award for short fiction, presented by a jury. one notable award for science fiction films and tv programs is the saturn award, which is presented annually by the academy of science fiction, fantasy, and horror films. there are other national awards, like canada ' s prix aurora awards, regional awards, like the endeavour award presented at orycon for works from the u. s. pacific northwest, and special interest or subgenre awards such as the chesley award for art, presented by the association of science fiction & fantasy artists, or the world fantasy award for fantasy. magazines may organize reader polls, notably the locus award. = = = conventions = = = conventions ( in fandom, often shortened as " cons ", such as " comic - con " ) are held in cities around the world, catering to a local, regional, national, or international membership. general - interest conventions cover all aspects of science fiction, while others focus on a particular interest like media fandom, filking, and others. most science fiction conventions are organized by volunteers in non - profit groups, though most media - oriented events are organized by commercial promoters. = = = fandom and fanzines = = = science fiction fandom emerged from the letters column in amazing stories magazine. soon fans began writing letters to each other, and then grouping their comments together in informal publications that became known as fanzines. once in regular contact, fans wanted to meet each other and organized local clubs. in the 1930s, the first science fiction conventions gathered fans from a wider area. the earliest organized online fandom was the sf lovers community, originally a mailing list in the late 1970s with a text archive file that was updated regularly. in the 1980s, usenet groups greatly expanded the circle of fans online. in the 1990s, the development of the world - wide web increased the community of online fan
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https://en.wikipedia.org/wiki/Science_fiction
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wounds, burns, ulcers, swollen glands, tumors, headaches, and bad breath. the edwin smith papyrus, written at about the same time, contains a surgical manual for treating wounds, fractures, and dislocations. the egyptians believed that the effectiveness of their medicines depended on the preparation and administration under appropriate rituals. medical historians believe that ancient egyptian pharmacology, for example, was largely ineffective. both the ebers and edwin smith papyri applied the following components to the treatment of disease : examination, diagnosis, treatment, and prognosis, which display strong parallels to the basic empirical method of science and, according to g. e. r. lloyd, played a significant role in the development of this methodology. = = = = calendar = = = = the ancient egyptians even developed an official calendar that contained twelve months, thirty days each, and five days at the end of the year. unlike the babylonian calendar or the ones used in greek city - states at the time, the official egyptian calendar was much simpler as it was fixed and did not take lunar and solar cycles into consideration. = = = mesopotamia = = = the ancient mesopotamians had extensive knowledge about the chemical properties of clay, sand, metal ore, bitumen, stone, and other natural materials, and applied this knowledge to practical use in manufacturing pottery, faience, glass, soap, metals, lime plaster, and waterproofing. metallurgy required knowledge about the properties of metals. nonetheless, the mesopotamians seem to have had little interest in gathering information about the natural world for the mere sake of gathering information and were far more interested in studying the manner in which the gods had ordered the universe. biology of non - human organisms was generally only written about in the context of mainstream academic disciplines. animal physiology was studied extensively for the purpose of divination ; the anatomy of the liver, which was seen as an important organ in haruspicy, was studied in particularly intensive detail. animal behavior was also studied for divinatory purposes. most information about the training and domestication of animals was probably transmitted orally without being written down, but one text dealing with the training of horses has survived. = = = = mesopotamian medicine = = = = the ancient mesopotamians had no distinction between " rational science " and magic. when a person became ill, doctors prescribed magical formulas to be recited as well as medicinal treatments. the earliest medical prescriptions appear in sumerian during the third dynasty of ur ( c. 2112 bce – c
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https://en.wikipedia.org/wiki/History_of_science
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we explore a new class of ads $ _ 3 $ solutions in massive type iia supergravity preserving $ \ mathcal { n } = ( 0, 6 ) $ supersymmetry and realising an $ \ mathfrak { osp } ( 6 | 2 ) $ superconformal algebra. these solutions exhibit an so ( 6 ) - symmetric internal space constructed from a $ \ mathbb { cp } ^ 3 $, and are fully specified by a single cubic function controlling the fluxes and warping. we propose a brane box configuration underlying the solutions from which we construct a two - dimensional quiver gauge theory whose anomaly structure and central charge we analyse, and from which we can realise seiberg - like dualities as large gauge transformations. the brane box configuration suggests an interpretation of the solutions as dual to surface defects within the abj ( m ) theory. our findings provide a concrete setting for exploring holography beyond the abjm vacuum. remarkably, no explicit field theories are currently known to realise $ \ mathcal { n } = ( 0, 6 ) $ supersymmetry in two dimensions, making our setup a promising and largely unexplored direction for field - theoretic investigations.
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arxiv:2504.20864
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finding relevant literature underpins the practice of evidence - based medicine. from 2014 to 2016, trec conducted a clinical decision support track, wherein participants were tasked with finding articles relevant to clinical questions posed by physicians. in total, 87 teams have participated over the past three years, generating 395 runs. during this period, each team has trialled a variety of methods. while there was significant overlap in the methods employed by different teams, the results were varied. due to the diversity of the platforms used, the results arising from the different techniques are not directly comparable, reducing the ability to build on previous work. by using a stable platform, we have been able to compare different document and query processing techniques, allowing us to experiment with different search parameters. we have used our system to reproduce leading teams runs, and compare the results obtained. by benchmarking our indexing and search techniques, we can statistically test a variety of hypotheses, paving the way for further research.
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arxiv:1801.09322
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we compare the half - light circular velocities, v _ { 1 / 2 }, of dwarf galaxies in the local group to the predicted circular velocity curves of galaxies in the nihao suite of lcdm simulations. we use a subset of 34 simulations in which the central galaxy has a stellar luminosity in the range 0. 5 x 10 ^ 5 < l _ v < 2 x 10 ^ 8 l _ { sun }. the nihao galaxy simulations reproduce the relation between stellar mass and halo mass from abundance matching, as well as the observed half - light size vs luminosity relation. the corresponding dissipationless simulations over - predict the v _ { 1 / 2 }, recovering the problem known as too big to fail ( tbtf ). by contrast, the nihao simulations have expanded dark matter haloes, and provide an excellent match to the distribution of v _ { 1 / 2 } for galaxies with l _ v > 2 x 10 ^ 6 l _ { sun }. for lower luminosities our simulations predict very little halo response, and tend to over predict the observed circular velocities. in the context of lcdm, this could signal the increased stochasticity of star formation in haloes below m _ { halo } \ sim 10 ^ { 10 } m _ { sun }, or the role of environmental effects. thus, haloes that are " too big to fail ", do not fail lcdm, but haloes that are " too small to pass " ( the galaxy formation threshold ) provide a future test of lcdm.
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arxiv:1512.00453
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putative global minima have been located for clusters interacting with an aluminium glue potential for n < 190. virtually all the clusters have polytetrahedral structures, which for larger sizes involve an ordered array of disclinations that are similar to those in the z, h and sigma frank - kasper phases. comparisons of sequences of larger clusters suggest that the majority of the global minima will adopt the bulk face - centred - cubic structure beyond n = 500.
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arxiv:cond-mat/0301374
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experimental realization and quantitative investigation of common - noise - induced synchronization of limit - cycle oscillations subject to random telegraph signals are performed using an electronic oscillator circuit. based on our previous formulation [ k. nagai et al., phys. rev. e 71, 036217 ( 2005 ) ], dynamics of the circuit is described as random - phase mappings between two limit cycles. lyapunov exponents characterizing the degree of synchronization are estimated from experimentally determined phase maps and compared with linear damping rates of phase differences measured directly. noisy on - off intermittency of the phase difference as predicted by the theory is also confirmed experimentally.
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arxiv:0904.2439
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we prove that the passive scalar field in the ornstein - uhlenbeck velocity field with wave - number dependent correlation times converges, in the white - noise limit, to that of kraichnan ' s model with higher spatial regularity.
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arxiv:math-ph/0209011
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the classical square well potential is smoothed with a finite range smoothing function in order to get a new simple strictly finite range form for the phenomenological nuclear potential. the smoothed square well form becomes exactly zero smoothly at a finite distance, in contrast to the woods - saxon form. if the smoothing range is four times the diffuseness of the woods - saxon shape both the central and the spin - orbit terms of the woods - saxon shape are reproduced reasonably well. the bound single particle energies in a woods - saxon potential can be well reproduced with those in the smoothed square well potential. the same is true for the complex energies of the narrow resonances.
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arxiv:1707.00620
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the fast computation of large kernel sums is a challenging task, which arises as a subproblem in any kernel method. we approach the problem by slicing, which relies on random projections to one - dimensional subspaces and fast fourier summation. we prove bounds for the slicing error and propose a quasi - monte carlo ( qmc ) approach for selecting the projections based on spherical quadrature rules. numerical examples demonstrate that our qmc - slicing approach significantly outperforms existing methods like ( qmc - ) random fourier features, orthogonal fourier features or non - qmc slicing on standard test datasets.
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arxiv:2410.01316
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in line with the latest research, the task of identifying helpful reviews from a vast pool of user - generated textual and visual data has become a prominent area of study. effective modal representations are expected to possess two key attributes : consistency and differentiation. current methods designed for multimodal review helpfulness prediction ( mrhp ) face limitations in capturing distinctive information due to their reliance on uniform multimodal annotation. the process of adding varied multimodal annotations is not only time - consuming but also labor - intensive. to tackle these challenges, we propose an auto - generated scheme based on multi - task learning to generate pseudo labels. this approach allows us to simultaneously train for the global multimodal interaction task and the separate cross - modal interaction subtasks, enabling us to learn and leverage both consistency and differentiation effectively. subsequently, experimental results validate the effectiveness of pseudo labels, and our approach surpasses previous textual and multimodal baseline models on two widely accessible benchmark datasets, providing a solution to the mrhp problem.
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arxiv:2402.18107
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most experimental data on the single - molecule magnet mn $ _ { 12 } $ acetate have been successfully explained by the assumption that the mn $ _ { 12 } $ acetate has an effective ground - state spin of s = 10. however, the effect of the low - lying excited manifolds caused by interactions between mn spins has not been well understood. to investigate the features of the low - lying excited manifolds, the intramolecular exchange interactions are calculated using density - functional theory ( dft ). with the calculated exchange parameters, the energy gap between the s = 10 ground - state and the first excited - state manifold is calculated by diagonalization of the heisenberg hamiltonian. the upper limit on the energy gap is about 40. 5 k which is likely to be overestimated due to incomplete treatment of the coulomb potential within dft. it is found that there are several s = 9 low - energy excited - state manifolds above the s = 10 ground - state manifold. the magnetic anisotropy barriers for the low - lying spin excitations are calculated using dft. based on the calculations, it is found that the anisotropy barriers for the low - lying excited manifolds are approximately the same as that for the ground - state manifold, which is applicable to other single - molecule magnets such as mn $ _ 4 $.
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arxiv:cond-mat/0307707
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we consider statistical inference in factor analysis for ergodic and non - ergodic diffusion processes from discrete observations. factor model based on high frequency time series data has been mainly discussed in the field of high dimensional covariance matrix estimation. in this field, the method based on principal component analysis has been mainly used. however, this method is effective only for high dimensional model. on the other hand, there is a method based on the quasi - likelihood. however, since the factor is assumed to be observable, we cannot use this method when the factor is latent. thus, the existing methods are not effective when the factor is latent and the dimension of the observable variable is not so high. therefore, we propose an effective method in the situation.
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arxiv:2202.01481
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we address the properties of optical solitons that form in media with competing cubic - quintic nonlinearity and parity - time ( pt ) - symmetric complex - valued external potentials. the model describes the propagation of solitons in nonlinear optical waveguides with balanced gain and loss. we study the existence, stability, and robustness of fundamental, dipole, and multipole stationary solutions in this pt - symmetric system. the corresponding eigenvalue spectra diagrams for fundamental, dipole, tripole, and quadrupole solitons are presented. we show that the eigenvalue spectra diagrams for fundamental and dipole solitons merge at a coalescence point wc1, whereas the corresponding diagrams for tripole and quadrupole solitons merge at a larger coalescence point wc2. beyond these two merging points, i. e., when the gain - loss strength parameter w0 exceeds the corresponding coalescence points, the eigenvalue spectra cease to exist. the stability of the stationary solutions is investigated by performing the linear stability analysis and the robustness to propagation of these stationary solutions is checked by using direct numerical simulations.
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arxiv:1804.02629
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to each projection $ p $ in a $ c ^ * $ - algebra $ a $ we associate a family of derivations on $ a $, called $ p $ - derivations, and relate them to the space of triple derivations on $ p a ( 1 - p ) $. we then show that every derivation on a ternary ring of operators is spatial and we investigate whether every such derivation on a weakly closed ternary ring of operators is inner.
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arxiv:1712.03436
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large annotated datasets are required to train segmentation networks. in medical imaging, it is often difficult, time consuming and expensive to create such datasets, and it may also be difficult to share these datasets with other researchers. different ai models can today generate very realistic synthetic images, which can potentially be openly shared as they do not belong to specific persons. however, recent work has shown that using synthetic images for training deep networks often leads to worse performance compared to using real images. here we demonstrate that using synthetic images and annotations from an ensemble of 20 gans, instead of from a single gan, increases the dice score on real test images with 4. 7 % to 14. 0 % on specific classes.
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arxiv:2211.04086
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we introduce a class of self - similar sets which we call { \ em twofold cantor sets } $ k _ { pq } $ in $ \ mathbb r $ which are totally disconnected, do not have weak separation property and at the same time have isomorphic self - similar structures.
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arxiv:1802.03872
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in this note we study some of the properties of the generating polynomial for homomorphisms from a graph to at complete weighted graph on $ q $ vertices. we discuss how this polynomial relates to a long list of other well known graph polynomials and the partition functions for different spin models, many of which are specialisations of the homomorphism polynomial. we also identify the smallest graphs which are not determined by their homomorphism polynomials for $ q = 2 $ and $ q = 3 $ and compare this with the corresponding minimal examples for the $ u $ - polynomial, which generalizes the well known tutte - polynomal.
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arxiv:1401.6335
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we analyse the $ \ overline b _ s ^ 0 \ to k ^ + l ^ - \ bar \ nu $ and $ \ overline b _ s ^ 0 \ to k ^ { * + } ( \ to k \ pi ) \ ell ^ - \ bar \ nu $ decays that are valuable for extracting the ckm matrix element $ | v _ { ub } | $. we calculate the differential and integrated partial widths in units of $ | v _ { ub } | ^ 2 $ based on various calculations of hadronic form factors and in particular the latest lattice qcd calculation of the $ b _ s \ to k ^ * $ form factors. for the decay $ \ overline b _ s ^ 0 \ to k \ pi \ ell \ bar \ nu $, we formulate the general angular distributions with the inclusion of the various partial - wave $ k \ pi $ contributions. using the results for the $ k \ pi $ scalar form factor calculated from unitarized chiral perturbation theory, we explore the s - wave effects on angular distribution variables and demonstrate that they may not be negligible, considering the high precision expected in future measurements. we also briefly discuss the impact of the s - wave $ \ pi \ pi $ contributions in the $ b ^ - \ to \ pi ^ + \ pi ^ - \ ell \ bar \ nu $ decay and provide estimates for the mode $ b ^ - \ to k ^ + k ^ - \ ell \ bar \ nu $. the studies of these channels in future can not only be used to determine $ | v _ { ub } | $, but may also provide valuable information on the $ k \ pi $ and $ \ pi \ pi $ phase shifts.
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arxiv:1311.5420
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in multiple access channels ( mac ), multiple users share a transmission medium to communicate with a common receiver. traditional constellations like quadrature amplitude modulation are optimized for point - to - point systems and lack mechanisms to mitigate inter - user interference, leading to suboptimal performance in mac environments. to address this, we propose a novel framework for constellation design in mac that employs deep autoencoder ( dae ) - based communication systems. this approach intelligently creates flexible constellations aware of inter - user interference, reducing symbol error rate and enhancing the constellation - constrained sum capacity of the channel. comparisons against analytically derived constellations demonstrate that dae - designed constellations consistently perform best or equal to the best across various system parameters. furthermore, we apply the dae to scenarios where no analytical solutions have been developed, such as with more than two users, demonstrating the adaptability of the model.
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arxiv:2505.00868
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an heuristic signal processing scheme recently introduced shows how brain signals can be efficiently represented by a sparse spatiotemporal point process. the approach has been validated already for different relevant conditions demonstrating that preserves and compress a surprisingly large fraction of the signal information. in this paper the conditions for such compression to succeed are investigated as well as the underlying reasons for such good performance. the results show that the key lies in the correlation properties of the time series under consideration. it is found that signals with long range correlations are particularly suitable for this type of compression, where inflection points contain most of the information. since this type of correlation is ubiquitous in signals trough out nature including music, weather patterns, biological signals, etc., we expect that this type of approach to be an useful tool for their analysis.
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arxiv:1707.00759
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we report on the spectroscopic transit of the massive hot - jupiter corot - exo - 2b observed with the high - precision spectrographs sophie and harps. by modeling the radial velocity anomaly occurring during the transit due to the rossiter - mclaughlin ( rm ) effect, we determine the sky - projected angle between the stellar spin and the planetary orbital axis to be close to zero lambda = 7. 2 + - 4. 5 deg, and we secure the planetary nature of corot - exo - 2b. we discuss the influence of the stellar activity on the rm modeling. spectral analysis of the parent star from harps spectra are presented.
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arxiv:0803.3209
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in astrophysics, turbulent diffusion is often used in place of microphysical diffusion to avoid resolving the small scales. however, we expect this approach to break down when time and length scales of the turbulence become comparable with other relevant time and length scales in the system. turbulent diffusion has previously been applied to the magneto - rotational instability ( mri ), but no quantitative comparison of growth rates at different turbulent intensities has been performed. we investigate to what extent turbulent diffusion can be used to model the effects of small - scale turbulence on the kinematic growth rates of the mri, and how this depends on angular velocity and magnetic field strength. we use direct numerical simulations in three - dimensional shearing boxes with periodic boundary conditions in the spanwise direction and additional random plane - wave volume forcing to drive a turbulent flow at a given length scale. we estimate the turbulent diffusivity using a mixing length formula and compare with results obtained with the test - field method. it turns out that the concept of turbulent diffusion is remarkably accurate in describing the effect of turbulence on the growth rate of the mri. no noticeable breakdown of turbulent diffusion has been found, even when time and length scales of the turbulence become comparable with those imposed by the mri itself. on the other hand, quenching of turbulent magnetic diffusivity by the magnetic field is found to be absent. turbulence reduces the growth rate of the mri in a way that is the same as microphysical magnetic diffusion.
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arxiv:1310.3157
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we describe the energy relaxation process produced by surface damping on lattices of classical anharmonic oscillators. spontaneous emergence of localised vibrations dramatically slows down dissipation and gives rise to quasi - stationary states where energy is trapped in the form of a gas of weakly interacting discrete breathers. in one dimension ( 1d ), strong enough on - - site coupling may yield stretched - - exponential relaxation which is reminiscent of glassy dynamics. we illustrate the mechanism generating localised structures and discuss the crucial role of the boundary conditions. for two - - dimensional ( 2d ) lattices, the existence of a gap in the breather spectrum causes the localisation process to become activated. a statistical analysis of the resulting quasi - stationary state through the distribution of breathers ' energies yield information on their effective interactions.
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arxiv:cond-mat/0210027
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circumbinary accretion disks have been examined, theoretically, for supermassive and intermediate mass black holes, however, disks for black hole masses in the ligo regime are poorly understood. assuming these binaries possess such a disk initially, the question we want to answer is : are they dissipated by outflows or accretion prior to inspiral? to study this problem we propose a novel approach, whereby we consider an approximate, analytic spacetime and solve the geodesic equation for particles in this spacetime so that we can determine the likely fate of particles coming from the accretion disk. preliminary indications suggest a likelihood of accretion prior to inspiral.
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arxiv:2209.15350
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a mid - point theorem is proved in an elementary way for the u type shape of functions that arise out of exponential quadratic functions. these results are inspired from epidemic patterns and growth over a time period. key words : natural numbers mapping, mean value theorem.
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arxiv:math/0511365
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by expressing polynomials in the basis of chebyshev polynomials, certain families of hyperbolic polynomials appear naturally. some of these families have all their roots in the interval $ [ - 2, 2 ] $. in many cases the span of the family of polynomials thus found is greater than 4, and we show that they are the minimal polynomials of salem numbers, possibly multiplied by some cyclotomic polynomials. in addition, we show how to compute the limit of the largest and smallest roots.
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arxiv:1812.11869
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in this communication we introduce an efficient implementation of adaptive biasing that greatly improves the speed of free energy computation in molecular dynamics simulations. we investigated the use of accelerated simulations to inform on compound design using a recently reported and clinically relevant inhibitor of the chromatin regulator brd4. benchmarking on our local compute cluster, our implementation achieves up to 2. 5 times more force calls per day than plumed2. results of five 1 { \ mu } second - long simulations are presented, which reveal a conformational switch in the brd4 inhibitor between a binding competent and incompetent state. stabilization of the switch led to a - 3 kcal / mol improvement of absolute binding free energy. these studies suggest an unexplored ligand design principle and offer new actionable hypotheses for medicinal chemistry efforts against this druggable epigenetic target class.
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arxiv:1609.09833
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automatic augmentation methods have recently become a crucial pillar for strong model performance in vision tasks. while existing automatic augmentation methods need to trade off simplicity, cost and performance, we present a most simple baseline, trivialaugment, that outperforms previous methods for almost free. trivialaugment is parameter - free and only applies a single augmentation to each image. thus, trivialaugment ' s effectiveness is very unexpected to us and we performed very thorough experiments to study its performance. first, we compare trivialaugment to previous state - of - the - art methods in a variety of image classification scenarios. then, we perform multiple ablation studies with different augmentation spaces, augmentation methods and setups to understand the crucial requirements for its performance. additionally, we provide a simple interface to facilitate the widespread adoption of automatic augmentation methods, as well as our full code base for reproducibility. since our work reveals a stagnation in many parts of automatic augmentation research, we end with a short proposal of best practices for sustained future progress in automatic augmentation methods.
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arxiv:2103.10158
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this paper introduces a novel approach to membership inference attacks ( mia ) targeting stable diffusion computer vision models, specifically focusing on the highly sophisticated stable diffusion v2 by stabilityai. mias aim to extract sensitive information about a model ' s training data, posing significant privacy concerns. despite its advancements in image synthesis, our research reveals privacy vulnerabilities in the stable diffusion models ' outputs. exploiting this information, we devise a black - box mia that only needs to query the victim model repeatedly. our methodology involves observing the output of a stable diffusion model at different generative epochs and training a classification model to distinguish when a series of intermediates originated from a training sample or not. we propose numerous ways to measure the membership features and discuss what works best. the attack ' s efficacy is assessed using the roc auc method, demonstrating a 60 \ % success rate in inferring membership information. this paper contributes to the growing body of research on privacy and security in machine learning, highlighting the need for robust defenses against mias. our findings prompt a reevaluation of the privacy implications of stable diffusion models, urging practitioners and developers to implement enhanced security measures to safeguard against such attacks.
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arxiv:2311.09355
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objective functions based on hellinger distance yield robust and efficient estimators of model parameters. motivated by privacy and regulatory requirements encountered in contemporary applications, we derive in this paper \ emph { private minimum hellinger distance estimators }. the estimators satisfy a new privacy constraint, namely, hellinger differential privacy, while retaining the robustness and efficiency properties. we demonstrate that hellinger differential privacy shares several features of standard differential privacy while allowing for sharper inference. additionally, for computational purposes, we also develop hellinger differentially private gradient descent and newton - raphson algorithms. we illustrate the behavior of our estimators in finite samples using numerical experiments and verify that they retain robustness properties under gross - error contamination.
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arxiv:2501.14974
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in this paper we give a general introduction to quantum critical phenomena, which we practically illustrate by a detailed study of the low energy properties of the spin boson model ( sbm ), describing the dynamics of a spin 1 / 2 impurity ( or more generically a two - level system ) coupled to a bath of independent harmonic oscillators. we show that the behavior of the model is very sensitive to the bath spectrum, in particular how the properties of the quantum critical point in the sbm are affected by the functional form of the bath density of states ( dos ). to this effect, we review the renormalization group ( rg ) treatment of the sbm for various bath dos, based on an unconventional majorana representation of the spin 1 / 2 degree of freedom. we also discuss the derivation of shiba ' s relation for the sub - ohmic sbm, and explicitely derive an effective action vindicating the quantum to classical mapping.
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arxiv:1106.2654
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we write down an explicit conjecture for the instanton partition functions in 4d n = 2 su ( n ) gauge theories in the presence of a certain type of surface operator. these surface operators are classified by partitions of n, and for each partition there is an associated partition function. for the partition n = n we recover the nekrasov formalism, and when n = 1 +... + 1 we reproduce the result of feigin et. al. for the case n = 1 + ( n - 1 ) our expression is consistent with an alternative formulation in terms of a restricted su ( n ) xsu ( n ) instanton partition function. when n = 1 +... + 1 + 2 the partition functions can also be obtained perturbatively from certain w - algebras known as quasi - superconformal algebras, in agreement with a recent general proposal.
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arxiv:1012.1355
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0 | = 9 \ pm2 $ km s $ ^ { - 1 } $ kpc $ ^ { - 1 } $. the ratio of the radial component of the gravitational force produced by the spiral arms to the total gravitational force of the galaxy has been estimated to be $ f _ { r0 } = 0. 04 $.
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arxiv:1212.4750
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which constitutes anywhere from 30 % [ m / m ] to 90 % [ m / m ] of its composition by volume, yielding an array of materials with interesting thermomechanical properties. in the processing of glass - ceramics, molten glass is cooled down gradually before reheating and annealing. in this heat treatment the glass partly crystallizes. in many cases, so - called ' nucleation agents ' are added in order to regulate and control the crystallization process. because there is usually no pressing and sintering, glass - ceramics do not contain the volume fraction of porosity typically present in sintered ceramics. the term mainly refers to a mix of lithium and aluminosilicates which yields an array of materials with interesting thermomechanical properties. the most commercially important of these have the distinction of being impervious to thermal shock. thus, glass - ceramics have become extremely useful for countertop cooking. the negative thermal expansion coefficient ( tec ) of the crystalline ceramic phase can be balanced with the positive tec of the glassy phase. at a certain point ( ~ 70 % crystalline ) the glass - ceramic has a net tec near zero. this type of glass - ceramic exhibits excellent mechanical properties and can sustain repeated and quick temperature changes up to 1000 °c. = = processing steps = = the traditional ceramic process generally follows this sequence : milling → batching → mixing → forming → drying → firing → assembly. milling is the process by which materials are reduced from a large size to a smaller size. milling may involve breaking up cemented material ( in which case individual particles retain their shape ) or pulverization ( which involves grinding the particles themselves to a smaller size ). milling is generally done by mechanical means, including attrition ( which is particle - to - particle collision that results in agglomerate break up or particle shearing ), compression ( which applies a forces that results in fracturing ), and impact ( which employs a milling medium or the particles themselves to cause fracturing ). attrition milling equipment includes the wet scrubber ( also called the planetary mill or wet attrition mill ), which has paddles in water creating vortexes in which the material collides and break up. compression mills include the jaw crusher, roller crusher and cone crusher. impact mills include the ball mill, which has media that tumble and fracture the material, or the resonantacoustic mixer. shaft impactors cause particle - to particle attrition and compression
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https://en.wikipedia.org/wiki/Ceramic_engineering
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we obtain restrictions on which groups can admit relatively anosov representations into specified target lie groups, by examining the topology of possible bowditch boundaries and how they interact with the anosov limit maps. for instance, we prove that, up to finite index, any group admitting a relatively anosov representation into sl ( 3, r ) is a free group or surface group, and any group admitting a relatively k - anosov representation into sp ( 2m, r ), where k is an odd integer between 1 and m, is a surface group or a free product of nilpotent groups. we also obtain a characterization of groups admitting relatively 1 - anosov representations into sl ( 4, r ), general bounds on the dimension of the bowditch boundary of groups admitting relatively anosov representations into sl ( d, r ), statements relating spheres in the bowditch boundary to the ( non - ) existence of relatively anosov representations, and a characterization of groups of cohomological dimension at least d - 1 admitting relatively 1 - anosov representations into sl ( d, r ).
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arxiv:2401.03050
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pre - transitional disks are protoplanetary disks with a gapped disk structure, potentially indicating the presence of young planets in these systems. in order to explore the structure of these objects and their gap - opening mechanism, we observed the pre - transitional disk v1247 orionis using the very large telescope interferometer, the keck interferometer, keck - ii, gemini south, and irtf. this allows us spatially resolve the au - scale disk structure from near - to mid - infrared wavelengths ( 1. 5 to 13 { \ mu } m ), tracing material at different temperatures and over a wide range of stellocentric radii. our observations reveal a narrow, optically - thick inner - disk component ( located at 0. 18 au from the star ) that is separated from the optically thick outer disk ( radii > 46 au ), providing unambiguous evidence for the existence of a gap in this pre - transitional disk. surprisingly, we find that the gap region is filled with significant amounts of optically thin material with a carbon - dominated dust mineralogy. the presence of this optically thin gap material cannot be deduced solely from the spectral energy distribution, yet it is the dominant contributor at mid - infrared wavelengths. furthermore, using keck / nirc2 aperture masking observations in the h, k ', and l ' band, we detect asymmetries in the brightness distribution on scales of about 15 - 40 au, i. e. within the gap region. the detected asymmetries are highly significant, yet their amplitude and direction changes with wavelength, which is not consistent with a companion interpretation but indicates an inhomogeneous distribution of the gap material. we interpret this as strong evidence for the presence of complex density structures, possibly reflecting the dynamical interaction of the disk material with sub - stellar mass bodies that are responsible for the gap clearing.
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arxiv:1304.2768
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in heavy - ion collisions, nuclear matter is subjected to extreme conditions in a highly dynamical, rapidly evolving environment. this poses a tremendous challenge for calculating jet quenching observables. current approaches rely on analytical results for static cases, introducing theoretical uncertainties and biases in our understanding of the pre - equilibrated medium. to address this issue, we employ resummation schemes to derive analytical rates for radiative energy loss in generic, evolving backgrounds. we investigate regimes where rare scattering and multiple scattering with the dynamical medium occurs, and extract relevant scales governing the in - medium emission rate of soft gluons. our analysis indicates that strong jet quenching is only possible when the equilibration time of the medium is longer than its mean free path, highlighting the importance of medium modifications of jets in the earliest stages of heavy - ion collisions. we also demonstrate analytically that a medium evolution, which initially has a small coupling to jets, typically leads to a stronger jet azimuthal asymmetry at the same jet suppression factor.
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arxiv:2409.04295
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ip exchange or ipx is gsma proposal for ip interconnection model which supports multi services to offer end - to - end qos, security, interoperability, slas through a dedicated connection. there are some possible partnership schemes between ipx providers such as peering mode, semi - hosted mode, full - hosted mode, or combination between these modes. the implementation of the schemes will be case - by - case basis with some considerations based on, but not limited to, ipx providers network asset, coverage, services, features offer, commercial offer, and customers. for an ipx provider to become competitive in ipx business and become a global ipx hub, some value added should be considered such as cost efficiency and great network performance. to achieve it, an ipx provider could implement some strategies such as build network sinergy between them and partners to develop ipx service as single offering, offer their customers with bundled access network and services. an ipx provider should also consider their existing customer - based that can be a benefit to their bargaining position to other potential ipx provider partners to determine price and business scheme for partnership.
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arxiv:1404.2989
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epithelial - mesenchymal transition ( emt ), and the corresponding reverse process, mesenchymal - epithelial transition ( met ), are dynamic and reversible cellular programs orchestrated by many changes at biochemical and morphological levels. a recent surge in identifying the molecular mechanisms underlying emt / met has led to the development of various mathematical models that have contributed to our improved understanding of dynamics at single - cell and population levels : a ) multi - stability ( how many phenotypes can cells attain en route emt / met? ), b ) reversibility / irreversibility ( what time and / or concentration of an emt inducer marks the ' tipping point ' when cells induced to undergo emt cannot revert? ), c ) symmetry in emt / met ( do cells take the same path while reverting as they took during the induction of emt? ), and d ) non - cell autonomous mechanisms ( how does a cell undergoing emt alter the tendency of its neighbors to undergo emt? ). these dynamical traits may facilitate a heterogeneous response within a cell population undergoing emt / met. here, we present a few examples of designing different mathematical models that can contribute to decoding emt / met dynamics.
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arxiv:1907.11174
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legal corpora for natural language processing ( nlp ) are valuable and scarce resources in languages like spanish due to two main reasons : data accessibility and legal expert knowledge availability. inesdata 2024 is a european union funded project lead by the universidad polit \ ' ecnica de madrid ( upm ) and developed by instituto de ingenier \ ' ia del conocimiento ( iic ) to create a series of state - of - the - art nlp resources applied to the legal / administrative domain in spanish. the goal of this paper is to present the corpus of legal spanish contract clauses ( 3cel ), which is a contract information extraction corpus developed within the framework of inesdata 2024. 3cel contains 373 manually annotated tenders using 19 defined categories ( 4 782 total tags ) that identify key information for contract understanding and reviewing.
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arxiv:2501.15990
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we analyze the final release of the planck satellite data to constrain the gravitational lensing potential in a model - independent manner. the amount of lensing determined from the smoothing of the acoustic peaks in the temperature and polarization power spectra is 2 $ \ sigma $ too high when compared with the measurements using the lensing reconstruction and 2. 8 $ \ sigma $ too high when compared with $ \ lambda $ cdm expectation based on the " unlensed " portion of the temperature and polarization power spectra. the largest change from the previous data release is the $ \ lambda $ cdm expectation, driven by improved constraints to the optical depth to reionization. the anomaly still is inconsistent with actual gravitational lensing, given that the lensing reconstruction constraints are discrepant independent of the model. within the context of $ \ lambda $ cdm, improvements in its parameter constraints from lensing reconstruction bring this tension to 2. 1 $ \ sigma $ and from further adding baryon acoustic oscillation and pantheon supernova data to a marginally higher 2. 2 $ \ sigma $. once these other measurements are included, marginalizing this lensing - like anomaly cannot substantially resolve tensions with low - redshift measurements of $ h _ 0 $ and $ s _ 8 $ in $ \ lambda $ cdm, $ \ lambda $ cdm + $ n _ \ mathrm { eff } $ or $ \ lambda $ cdm + $ \ sum m _ \ nu $ ; furthermore the artificial strengthening of constraints on $ \ sum m _ \ nu $ is less than 20 %.
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arxiv:1912.06601
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the phonon spectrum of cubic cadmium metastannate and the crystal structures of its distorted phases were calculated from first principles within the density functional theory. it is shown that the phonon spectrum and the energy spectrum of distorted phases in $ \ alpha $ - cdsno $ _ 3 $ are surprisingly similar to the corresponding spectra of cdtio $ _ 3 $. the ground state of $ \ alpha $ - cdsno $ _ 3 $ is the ferroelectric $ pbn2 _ 1 $ phase ; the energy gain accompanying the phase transition from the nonpolar $ pbnm $ phase to this phase is $ \ sim $ 30 mev and the spontaneous polarization in it is 0. 25 c / m $ ^ 2 $. an analysis of the eigenvector of the ferroelectric mode in $ \ alpha $ - cdsno $ _ 3 $ and calculations of the partial densities of states indicates that the ferroelectric instability in this crystal, which does not contain $ d $ transition elements, is associated with the formation of a covalent bonding between cd and o atoms.
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arxiv:1601.01472
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gw number count can be used as a novel tracer of the large scale structure ( lss ) in the luminosity distance space ( lds ), just like galaxies in the redshift space. it is possible to obtain the $ d _ l - d _ a $ duality relation with clustering effect. however, several lss induced errors will contaminate the gw luminosity distance measurement, such as the peculiar velocity dispersion error of the host galaxy as well as the foreground lensing magnification. the distance uncertainties induced from these effects will degrade the gw clustering from a spectroscopic - like data down to a photometric - like data. in this paper, we investigate how these lss induced distance errors modify our cosmological parameter precision inferred from the lds clustering. we consider two of the next generation gw observatories, namely the big bang observatory ( bbo ) and the einstein telescope ( et ). we forecast the parameter estimation errors on the angular diameter distance $ d _ a $, luminosity distance space hubble parameter $ h _ l $ and structure growth rate $ f _ l \ sigma _ 8 $ with a fisher matrix method. generally speaking, the gw source clustering data can be used for cosmological studies below $ d _ l < 5 $ gpc, while above this scale the lensing errors will increase significantly. we find that for bbo, it is possible to constrain the cosmological parameters with a relative error of $ 10 ^ { - 3 } $ to $ 10 ^ { - 2 } $ below $ d _ l < 5 $ gpc. the velocity dispersion error is dominant in the low luminosity distance range, while the lensing magnification error is the bottleneck in the large luminosity distance range. to reduce the lensing error, we assumed a $ 50 \ % $ delensing efficiency. even with this optimal assumption, the fractional error increased to $ o ( 1 ) $ at luminosity distance $ d _ l = 25 $ gpc. the results for et are similar as those from bbo. due to the gw source number in et is less than that from bbo, the corresponding results also get a bit worse.
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arxiv:2209.01359
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we review progress in the hydrodynamic description of heavy - ion collisions, focusing on recent developments in modeling the fluctuating initial state and event - by - event viscous hydrodynamic simulations. we discuss how hydrodynamics can be used to extract information on fundamental properties of quantum - chromo - dynamics from experimental data, and review successes and challenges of the hydrodynamic framework.
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arxiv:1301.5893
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the leading - particle effect and the factorization property of the scattering amplitude in the impact parameter space are used to study semiclassical production of pions in the central region. the mechanism is related to the isospin - uniform solution of the nonlinear $ \ sigma $ - model coupled to quark degrees of freedom. the multipion exchange potential between two quarks is derived. it is shown thatthe soft chiral pion bremsstralung also leads to anomalously large fluctuations in the ratio of neutral to charged pions. we show that only direct production ofpions in the form of an isoscalar coherent pulse without isovector pairs can lead to large neutral - charged fluctuations.
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arxiv:hep-ph/9907566
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when engaging in collaborative tasks, humans efficiently exploit the semantic structure of a conversation to optimize verbal and nonverbal interactions. but in recent " language to code " or " language to action " models, this information is lacking. we show how incorporating the prior discourse and nonlinguistic context of a conversation situated in a nonlinguistic environment can improve the " language to action " component of such interactions. we finetune an llm to predict actions based on prior context ; our model, nebula, doubles the net - action f1 score over the baseline on this task of jayannavar et al. ( 2020 ). we also investigate our model ' s ability to construct shapes and understand location descriptions using a synthetic dataset
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arxiv:2406.18164
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we show that the normal state transport properties of nano - scale granular aluminum films, near the metal to insulator transition, present striking similarities with those of kondo systems. those include a negative magneto - resistance, a minimum of resistance r at a temperature tm in metallic films, a logarithmic rise at low temperatures and a negative curvature of r ( t ) at high temperatures. these normal state properties are interpreted in terms of spin - flip scattering of conduction electrons by local magnetic moments, possibly located at the metal / oxide interfaces. their co - existence with the enhanced superconductivity seen in these films is discussed.
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arxiv:1207.0970
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digital circuits based on residue number systems have been considered to produce a pseudo - random behavior. the present work is an initial step towards the complete implementation of those systems for similar applications using quantum technology. we propose the implementation of a quasi - chaotic oscillator based on quantum modular addition and multiplication and we prove that quantum computing allows the parallel processing of data, paving the way for a fast and robust multi - channel encryption / decryption scheme. the resulting structure is assessed by several experiments in order to ascertain the desired noise - like behavior.
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arxiv:2203.14029
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we consider the classical molecular beam epitaxy ( mbe ) model with logarithmic type potential known as no - slope - selection. we employ a third order backward differentiation ( bdf3 ) in time with implicit treatment of the surface diffusion term. the nonlinear term is approximated by a third order explicit extrapolation ( ep3 ) formula. we exhibit mild time step constraints under which the modified energy dissipation law holds. we break the second dahlquist barrier and develop a new theoretical framework to prove unconditional uniform energy boundedness with no size restrictions on the time step. this is the first unconditional result for third order bdf methods applied to the mbe models without introducing any stabilization terms or fictitious variables. a novel theoretical framework is also established for the error analysis of high order methods.
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arxiv:2106.08041
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observations of the high - redshift universe with the 21 cm hyperfine line of neutral hydrogen promise to open an entirely new window onto the early phases of cosmic structure formation. here we review the physics of the 21 cm transition, focusing on processes relevant at high redshifts, and describe the insights to be gained from such observations. these include measuring the matter power spectrum at z ~ 50, observing the formation of the cosmic web and the first luminous sources, and mapping the reionization of the intergalactic medium. the epoch of reionization is of particular interest, because large hii regions will seed substantial fluctuations in the 21 cm background. we also discuss the experimental challenges involved in detecting this signal, with an emphasis on the galactic and extragalactic foregrounds. these increase rapidly toward low frequencies and are especially severe for the highest redshift applications. assuming that these difficulties can be overcome, the redshifted 21 cm line will offer unique insight into the high - redshift universe, complementing other probes but providing the only direct, three - dimensional view of structure formation from z ~ 200 to z ~ 6.
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arxiv:astro-ph/0608032
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accurately predicting the performance of different optimization algorithms for previously unseen problem instances is crucial for high - performing algorithm selection and configuration techniques. in the context of numerical optimization, supervised regression approaches built on top of exploratory landscape analysis are becoming very popular. from the point of view of machine learning ( ml ), however, the approaches are often rather naive, using default regression or classification techniques without proper investigation of the suitability of the ml tools. with this work, we bring to the attention of our community the possibility to personalize regression models to specific types of optimization problems. instead of aiming for a single model that works well across a whole set of possibly diverse problems, our personalized regression approach acknowledges that different models may suite different types of problems. going one step further, we also investigate the impact of selecting not a single regression model per problem, but personalized ensembles. we test our approach on predicting the performance of numerical optimization heuristics on the bbob benchmark collection.
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arxiv:2104.10999
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a new method sreag ( spherical rectangular equal - area grid ) is proposed to divide a spherical surface into equal - area cells. the method is based on dividing a sphere into latitudinal rings of near - constant width with further splitting each ring into equal - area cells. it is simple in construction and use, and provides more uniform width of the latitudinal rings than other methods of equal - area pixelization of a spherical surface. the new method provides a rectangular grid cells with the latitude - and longitude - oriented boundaries, near - square cells in the equatorial rings, and the closest to uniform width of the latitudinal rings as compared with other equal - area isolatitudinal grids. the binned data is easy to visualize and interpret in terms of the longitude - latitude rectangular coordinate system, natural for astronomy and geodesy. grids with arbitrary number of rings and, consequently, wide and theoretically unlimited range of cell size can be built by the proposed method. comparison with other methods used in astronomical research showed the advantages of the new approach in sense of uniformity of the ring width, a wider range of grid resolution, and simplicity of use.
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arxiv:1909.04701
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of stellenbosch - bachelor of military science ( bmil ), master of military science ( mmil ), mphil in security management united states : united states air force academy – major in military and strategic studies ; minor in nuclear weapons and strategy united states military academy – major in defense and strategic studies hawaii pacific university – major in diplomacy and military studies missouri state university – minor in military studies = = international military sciences or studies associations = = there are many international associations with the core purpose of bringing scholars in the field of military science together. some are inter - disciplinary and have a broad scope, whilst others are confined and specialized focusing on more specific disciplines or subjects. some are integrated in larger scientific communities like the international sociological association ( isa ) and the american psychological association ( apa ) where others have grown out of military institutions or individuals who have had a particular interest in areas of military science and are military, defense or armed forces oriented. some of these associations are : american psychological association ; division 19 : society for military psychology ( apa - div19 ) european research group on military and society ( ergomas ) inter - university seminar on armed forces and society ( ius ) international congress on soldiers physical performance ( icspp ) international military testing association ( imta ) international society of military sciences ( isms ) international sociological association ; rc01 armed forces and conflict resolution international association for military pedagogy = = military studies journals = = the following are notable journals in the field : = = see also = = military doctrine – codified expression of how fighters conduct campaigns, operations, battles and engagements military theory – study of the theories of war and warfare war – intense armed conflict list of basic military science and technology topics – overview of and topical guide to military science and technologypages displaying short descriptions of redirect targets list of military inventions list of military writers philosophy of war – theory of causes and ethics of armed conflict = = references = = notes bibliography = = external links = = military technology us military / government texts the logic of warfighting experiments by kass ( ccrp, 2006 ) complexity, networking, and effects based approaches to operations by smith ( ccrp, 2006 ) understanding command and control by alberts and hayes ( ccrp, 2006 ) the agile organization by atkinson and moffat ( ccrp, 2005 ) power to the edge by alberts and hayes ( ccrp, 2003 ) network centric warfare by alberts et al. ( ccrp, 1999 )
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https://en.wikipedia.org/wiki/Military_science
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we study the problem of unsupervised skill discovery, whose goal is to learn a set of diverse and useful skills with no external reward. there have been a number of skill discovery methods based on maximizing the mutual information ( mi ) between skills and states. however, we point out that their mi objectives usually prefer static skills to dynamic ones, which may hinder the application for downstream tasks. to address this issue, we propose lipschitz - constrained skill discovery ( lsd ), which encourages the agent to discover more diverse, dynamic, and far - reaching skills. another benefit of lsd is that its learned representation function can be utilized for solving goal - following downstream tasks even in a zero - shot manner - i. e., without further training or complex planning. through experiments on various mujoco robotic locomotion and manipulation environments, we demonstrate that lsd outperforms previous approaches in terms of skill diversity, state space coverage, and performance on seven downstream tasks including the challenging task of following multiple goals on humanoid. our code and videos are available at https : / / shpark. me / projects / lsd /.
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arxiv:2202.00914
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the first part of this paper contains a brief description of the beginnings of modern cosmology, which, the author will argue, was most likely born in the year 1912. some of the pieces of evidence presented here have emerged from recent research in the history of science, and are not usually shared with the general audiences in popular science books. in special, the issue of the correct formulation of the original big bang concept, according to the precise words of fred hoyle, is discussed. too often, this point is very deficiently explained ( when not just misleadingly ) in most of the available generalist literature. other frequent uses of the same words, big bang, as to name the initial singularity of the cosmos, and also whole cosmological models, are then addressed, as evolutions of its original meaning. quantum and inflationary additions to the celebrated singularity theorems by penrose, geroch, hawking and others led to subsequent results by borde, guth and vilenkin. and corresponding corrections to the einstein field equations have originated, in particular, $ r ^ 2 $, $ f ( r ) $, and scalar - tensor gravities, giving rise to a plethora of new singularities. for completeness, an updated table with a classification of the same is given.
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arxiv:1801.09550
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we use a swap monte carlo algorithm to numerically prepare bulk glasses with kinetic stability comparable to that of glass films produced experimentally by physical vapor deposition. by melting these systems into the liquid state, we show that some of our glasses retain their amorphous structures longer than 10 ^ 5 times the equilibrium structural relaxation time. this exceptional kinetic stability cannot be achieved experimentally for bulk materials. we perform simulations at both constant volume and constant pressure to demonstrate that the density mismatch between the ultrastable glass and the equilibrium liquid accounts for a major part of the observed kinetic stability.
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arxiv:1706.10081
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we study d - dimensional generalizations of three mutually related topics in graph theory : hamiltonian paths, ( unit ) interval graphs, and binomial edge ideals. we provide partial high - dimensional generalizations of ore and posa ' s sufficient conditions for a graph to be hamiltonian. we introduce a hierarchy of combinatorial properties for simplicial complexes that generalize unit - interval, interval, and co - comparability graphs. we connect these properties to the already existing notions of determinantal facet ideals and hamiltonian paths in simplicial complexes. some important consequences of our work are : ( 1 ) every almost - closed strongly - connected d - dimensional simplicial complex is traceable. ( this extends the well - known result " unit - interval connected graphs are traceable ". ) ( 2 ) every almost - closed d - complex that remains strongly connected after the deletion of d or less vertices, is hamiltonian. ( this extends the fact that " unit - interval 2 - connected graphs are hamiltonian ". ) ( 3 ) unit - interval complexes are characterized, among traceable complexes, by the property that the minors defining their determinantal facet ideal form a groebner basis for a diagonal term order which is compatible with the traceability of the complex. ( this corrects a recent theorem by ene et al., extends a result by herzog and others, and partially answers a question by almousa - vandebogert. ) ( 4 ) only the d - skeleton of the simplex has a determinantal facet ideal with linear resolution. ( this extends the result by kiani and saeedi - madani that " only the complete graph has a binomial edge ideal with linear resolution ". ) ( 5 ) the determinantal facet ideals of all under - closed and semi - closed complexes have a square - free initial ideal with respect to lex. in characteristic p, they are even f - pure.
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arxiv:2101.09243
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the relationship between the distribution of zeros of an infinite blaschke product $ b $ and the inclusion in weighted bergman spaces $ a _ { \ alpha } ^ p $ of the derivative of $ b $ or the derivative of functions in its model space $ h ^ 2 \ ominus bh ^ 2 $ is investigated.
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arxiv:1909.02135
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we extend the scope of azadkia - chatterjee ' s dependence coefficient between a scalar response $ y $ and a multivariate covariate $ x $ to the case where $ x $ takes values in a general metric space. particular attention is paid to the case where $ x $ is a curve. although extending this framework at the population level is relatively straightforward, analyzing the asymptotic behavior of the estimator proves to be complex. this complexity is largely related to the nearest neighbor structure of the infinite - dimensional covariate sample, leading us to explore a topic that has not been previously addressed in the literature. the primary contribution of this paper is to provide insights into this issue and propose strategies to address it. our findings also have significant implications for other graph - based methods facing similar challenges.
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arxiv:2405.07732
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we compute bottomonium suppression and elliptic flow within the pnrqcd effective field theory using an open quantum systems approach. for the hydrodynamical background, we use 2 + 1d music second - order viscous hydrodynamics with ip - glasma initial conditions and evolve bottom / antibottom quantum wave packets in real time in these backgrounds. we find that the impact of fluctuating initial conditions is small when compared to results obtained using smooth initial conditions. including the effect of fluctuating initial conditions, we find that the upsilon ( 1s ) integrated elliptic flow is v _ 2 [ 1s ] = 0. 005 + / - 0. 002 + / - 0. 001, with the first and second variations corresponding to statistical and systematic theoretical uncertainties, respectively.
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arxiv:2211.06363
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as humans, we can often detect from a persons utterances if he or she is in favor of or against a given target entity ( topic, product, another person, etc ). but from the perspective of a computer, we need means to automatically deduce the stance of the tweeter, given just the tweet text. in this paper, we present our results of performing stance detection on twitter data using a supervised approach. we begin by extracting bag - of - words to perform classification using timbl, then try and optimize the features to improve stance detection accuracy, followed by extending the dataset with two sets of lexicons - arguing, and mpqa subjectivity ; next we explore the malt parser and construct features using its dependency triples, finally we perform analysis using scikit - learn random forest implementation.
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arxiv:1703.02019
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a suite of input - to - state stability results are presented for a class of forced differential inclusions, so - called lur ' e inclusions. as a consequence, semi - global incremental input - to - state stability results for systems of forced lur ' e differential equations are derived. the results are in the spirit of the passivity theorem from control theory as both the linear and nonlinear components of the lur ' e inclusion ( or equation ) are assumed to satisfy passivity - type conditions. these results provide a basis for the analysis of forced lur ' e differential equations subject to ( almost ) periodic forcing terms and, roughly speaking, ensure the existence and attractivity of ( almost ) periodic state - and output - responses, comprising another focus of the present work. one ultimate aim of the study is to provide a robust and rigorous theoretical foundation for a well - defined and tractable ` ` frequency response ' ' of forced lur ' e systems.
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arxiv:2406.15099
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robots are increasingly expected to manipulate objects in ever more unstructured environments where the object properties have high perceptual uncertainty from any single sensory modality. this directly impacts successful object manipulation. in this work, we propose a reinforcement learning - based motion planning framework for object manipulation which makes use of both on - the - fly multisensory feedback and a learned attention - guided deep affordance model as perceptual states. the affordance model is learned from multiple sensory modalities, including vision and touch ( tactile and force / torque ), which is designed to predict and indicate the manipulable regions of multiple affordances ( i. e., graspability and pushability ) for objects with similar appearances but different intrinsic properties ( e. g., mass distribution ). a dqn - based deep reinforcement learning algorithm is then trained to select the optimal action for successful object manipulation. to validate the performance of the proposed framework, our method is evaluated and benchmarked using both an open dataset and our collected dataset. the results show that the proposed method and overall framework outperform existing methods and achieve better accuracy and higher efficiency.
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arxiv:2207.06608
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recent work has shown that more effective dense retrieval models can be obtained by distilling ranking knowledge from an existing base re - ranking model. in this paper, we propose a generic curriculum learning based optimization framework called cl - drd that controls the difficulty level of training data produced by the re - ranking ( teacher ) model. cl - drd iteratively optimizes the dense retrieval ( student ) model by increasing the difficulty of the knowledge distillation data made available to it. in more detail, we initially provide the student model coarse - grained preference pairs between documents in the teacher ' s ranking and progressively move towards finer - grained pairwise document ordering requirements. in our experiments, we apply a simple implementation of the cl - drd framework to enhance two state - of - the - art dense retrieval models. experiments on three public passage retrieval datasets demonstrate the effectiveness of our proposed framework.
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arxiv:2204.13679
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since hertz ' s pioneering work in 1882, contact mechanics traditionally grounds on linear elasticity, assuming small strains and displacements. however, recent experiments clearly highlighted linear elasticity limitations in accurately predicting the contact behaviour of rubbers and elastomers, particularly during frictional slip, which is governed by geometric and material nonlinearity. in this study, we investigate the basic scenario involving normal approach - retraction contact cycles between a wavy rigid indenter and a flat, deformable substrate. both frictionless and frictional interfacial conditions are examined, considering finite strains, displacements, and nonlinear rheology. we developed a finite element model for this purpose and compared our numerical results with westergaard ' s linear theory. our findings show that, even in frictionless conditions, the contact response is significantly influenced by geometric and material nonlinearity, particularly for wavy indenters with high aspect ratios, where normal - tangential stresses and displacements coupling emerges. more importantly, interfacial friction in nonlinear elasticity leads to contact hysteresis ( i. e., frictional energy dissipation ) during normal loading - unloading cycles. this behavior cannot be explained in a linear framework ; therefore, most of the experiments reporting hysteresis are typically explained invoking other interfacial phenomena ( e. g., adhesion, plasticity, or viscoelasticity ). here we present an additional suitable explanation relying on finite strains / displacements with detailed peculiarities, such as vanishing pull - off force. moreover, we also report an increase of hysteretic losses as for confined systems, stemming from the enhanced normal - tangential nonlinear coupling.
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arxiv:2503.07495
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the recursion operator and bi - hamiltonian formulation of the drinfeld - sokolov system are given
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arxiv:solv-int/9811013
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weighted finite automata and transducers ( including hidden markov models and conditional random fields ) are widely used in natural language processing ( nlp ) to perform tasks such as morphological analysis, part - of - speech tagging, chunking, named entity recognition, speech recognition, and others. parallelizing finite state algorithms on graphics processing units ( gpus ) would benefit many areas of nlp. although researchers have implemented gpu versions of basic graph algorithms, limited previous work, to our knowledge, has been done on gpu algorithms for weighted finite automata. we introduce a gpu implementation of the viterbi and forward - backward algorithm, achieving decoding speedups of up to 5. 2x over our serial implementation running on different computer architectures and 6093x over openfst.
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arxiv:1701.03038
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in this study, we devote our attention to the question of clarifying the existence of a weak solution to a class of quasilinear double - phase elliptic equations with logarithmic convection terms under some appropriate assumptions on data. the proof is based on the surjectivity theorem for the pseudo - monotone operators and modular function spaces and embedding theorems in generalized orlicz spaces. our approach in this paper can be extended naturally to a larger class of unbalanced double - phase problems with logarithmic perturbation and gradient dependence on the right - hand sides.
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arxiv:2309.06700
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