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forecasting is challenging since uncertainty resulted from exogenous factors exists. this work investigates the rank position forecasting problem in car racing, which predicts the rank positions at the future laps for cars. among the many factors that bring changes to the rank positions, pit stops are critical but irregular and rare. we found existing methods, including statistical models, machine learning regression models, and state - of - the - art deep forecasting model based on encoder - decoder architecture, all have limitations in the forecasting. by elaborative analysis of pit stops events, we propose a deep model, ranknet, with the cause effects decomposition that modeling the rank position sequence and pit stop events separately. it also incorporates probabilistic forecasting to model the uncertainty inside each sub - model. through extensive experiments, ranknet demonstrates a strong performance improvement over the baselines, e. g., mae improves more than 10 % consistently, and is also more stable when adapting to unseen new data. details of model optimization, performance profiling are presented. it is promising to provide useful forecasting tools for the car racing analysis and shine a light on solutions to similar challenging issues in general forecasting problems. | arxiv:2010.01707 |
gerhard had recently analyzed the data on seven dwarf spheroidals, and concluded that these disagree with the predictions of mond. we contend that this conclusion is anything but correct. with new data for three of the dwarfs the observations of all dwarfs are in compelling agreement with the predictions of mond. gerhard found mond m / l values that fall around a few solar units, as expected if mond is a valid alternative to dark matter. his sole cause for complaint was that some of his mond m / l values were still outside the range of ` ` reasonable ' ' stellar values. this, we say, was easily attributable to uncertainties in the data, such as in the velocity dispersions, luminosities, core radii, etc., and in the assumptions that underlie the analysis, such as isotropic velocity distribution, light - distribution fits, etc.. there are now new, much improved determinations of the velocity dispersions for three of the dwarfs, in particular for the two dwarfs for which gerhard found high mond m / l values. in fact, within just the quoted errors on the velocity dispersions and the luminosities, the mond m / l values for all seven dwarfs are now perfectly consistent with stellar values, with no need for dark matter. | arxiv:astro-ph/9503056 |
chirality, a fundamental property of asymmetric structures, plays a crucial role in pharmaceutical, biological and chemical systems, offering a powerful tool for screening organic compounds. while the conventional optical chirality detectors are often bulky and involuted, the topological insulators ( tis ) offer a promising platform for developing compact yet sensitive devices - owing to their inherent chirality. however, the complex interplay of photoresponses in tis can limit the ultimate accuracy of chirality detection. therefore, we here analyze the underlying mechanisms governing the photoresponses in tis and reveal strategies to enhance the helicity - dependent photocurrent ( hdpc ). by attentively analyzing the symmetries and behavior of competing photoresponses, we show that it is possible to effectively eliminate unwanted contributions and isolate the hdpc. moreover, we reveal that hdpc is strongly amplified in ultrathin ti films, and can be further enhanced by optimizing the illumination parameters, sensor strain and / or back gating. our findings thereby provide a roadmap for design and optimization of miniaturized, high - performance ti chirality detectors, with potential to revolutionize chiral analysis in biomedical and material sciences. | arxiv:2411.12040 |
there has been considerable interest in exploiting the spin degrees of freedom of electrons for potential information storage and computing technologies. topological insulators ( ti ), a class of quantum materials, have special gapless edge / surface states, where the spin polarization of the dirac fermions is locked to the momentum direction. this spin - momentum locking property gives rise to very interesting spin - dependent physical phenomena such as the edelstein and inverse edelstein effects. however, the spin injection in pure surface states of ti is very challenging because of the coexistence of the highly conducting bulk states. here, we experimentally demonstrate the spin injection and observe the inverse edelstein effect in the surface states of a topological kondo insulator, smb6. at low temperatures when only surface carriers are present, a clear spin signal is observed. furthermore, the magnetic field angle dependence of the spin signal is consistent with spin - momentum locking property of surface states of smb6. | arxiv:1610.00856 |
annual astrological calendars, practica and prognostications became widespread publications in europe after the invention of printing presses in the 15th century. using the national language instead of latin, the language of the scientists, the motion of sun, moon and planets were explained and used to foretell weather, growth of fruit, diseases, war and misfortune. by this means astronomical knowledge became accessible to everyone capable of reading. a milestone in the context of position calculations of bodies of our solar system was the publication of the copernican system in 1543. when victorinus sch \ " onfeldt started his studies at wittenberg university he was educated in the so called " wittenberg interpretation " of copernicus. in 1557 sch \ " onfeldt became professor of mathematics at marburg university and in 1566 he additionally was given a professorship of medicine with the help of his teachers and mentors in wittenberg sch \ " onfeldt was introduced to the court of the landgrave of hessen in marburg and became a close friend to the noble family. to wilhelm iv., landgrave of hessen - kassel from 1567, he served not only as one of the personal physicians but as a scientific counselor in the landgraves ' astronomical studies. presumably right after being appointed a professor of mathematics sch \ " onfeldt began to write his " \ emph { prognosticon astrologicum } ", a series of annual books, that he continued until his death. he made use the copernican system for his calculations, comparing them occasionally with calculations using new ptolemaic based ephemerides and in his last almanacs with calculations based on tycho brahes ' model. | arxiv:1801.00154 |
on the path towards power systems with high renewable penetrations and ultimately carbon - neutral, more and more synchronous generation is being displaced by variable renewable generation that does not currently provide system inertia nor reactive power support. this could create serious issues of power system stability in the near future, and countries with high renewable penetrations such as ireland are already facing these challenges. therefore, this paper aims at answering the questions of whether and how explicitly including inertia and reactive power constraints in generation expansion planning would affect the optimal capacity mix of the power system of the future. towards this end, we propose the novel low - carbon expansion generation optimization ( lego ) model, which explicitly accounts for : unit commitment constraints, rate of change of frequency ( rocof ) inertia requirements and virtual inertia provision, and, a second - order cone programming ( socp ) approximation of the ac power flow, accounting for reactive power constraints. an illustrative case study underlines that disregarding inertia and reactive power constraints in generation expansion planning can result in additional system cost, system infeasibilities, a distortion of optimal resource allocation and inability to reach established policy goals. | arxiv:2007.04843 |
this study is carried out in the framework of sample - return missions to asteroids that use a low - speed projectile as the primary component of its sampling mechanism ( e. g., jaxa ' s hayabusa and hayabusa2 missions ). we perform numerical simulations of such impacts into granular materials using different projectile shapes under earth ' s gravity. we then compare the amounts of ejected mass obtained in our simulations against what was found in experiments that used similar setups, which allows us to validate our numerical approach. for the targets, we consider 2 different monodisperse grain - diameter sizes : 5 mm and 3 mm. the impact speed of the projectile is 11 m s $ ^ { - 1 } $ directed downward, perpendicular to the surface of the targets. using an implementation of the soft - sphere discrete element method ( ssdem ) in the $ n $ - body gravity tree code pkdgrav, previously validated in the context of low - speed impacts into sintered glass bead agglomerates, we find a noticeable dependence of the amount of ejected mass on the projectile shape. as found in experiments, in the case of the larger target grain size ( 5 mm ), a conically shaped projectile ejects a greater amount of mass than do projectiles of other shapes, including disks and spheres. we then find that numerically the results are sensitive to the normal coefficient of restitution of the grains, especially for impacts into targets comprised of smaller grains ( 3 mm ). we also find that static friction plays a more important role for impacts into targets comprised of the larger grains. as a preliminary demonstration, one of these considered setups is simulated in a microgravity environment. as expected, a reduction in gravity increases both the amount of ejected mass and the timescale of the impact process. our methodology is also adaptable to the conditions of sampling mechanisms included in specific mission designs. | arxiv:1408.1979 |
in this paper, we shall discuss hilbert property of $ { \ rm hilb } ^ { g } ( \ mathbb { c } ^ { 3 } ) $, fujiki - oka resolutions and iterated fujiki - oka resolutions for three dimensional canonical cyclic quotient singularities by using the classification shown by ishida and iwashita \ cite { ii }. finally, we shall prove that there exists a hilbert desingularization for any three dimensional canonical cyclic quotient singularity. | arxiv:2108.02402 |
i show how space - like structures emerge within the topos - based approach to quantum mechanics. with a physical system, or, more generally, with an operationalistic setup a context category is associated being in fact an ordered collection of contexts. each context, in turn, is associated with certain configuration space. the minimax context principle is put forward. its basic idea is that among various configuration spaces the ` physical space ' is the configuration space of a structureless point particle. in order to implement it, two order relations on contexts are introduced being analogs of inner and outer daseinisation of projectors. the proposed minimax context principle captures two characteristic features of physical space : maximal with respect to refining the accuracy, and minimal by getting rid of extra degrees of freedom. | arxiv:1911.12136 |
we study the spectral determinant of the laplacian on finite graphs characterized by their number of vertices v and of bonds b. we present a path integral derivation which leads to two equivalent expressions of the spectral determinant of the laplacian either in terms of a v x v vertex matrix or a 2b x 2b link matrix that couples the arcs ( oriented bonds ) together. this latter expression allows us to rewrite the spectral determinant as an infinite product of contributions of periodic orbits on the graph. we also present a diagrammatic method that permits us to write the spectral determinant in terms of a finite number of periodic orbit contributions. these results are generalized to the case of graphs in a magnetic field. several examples illustrating this formalism are presented and its application to the thermodynamic and transport properties of weakly disordered and coherent mesoscopic networks is discussed. | arxiv:cond-mat/9911183 |
if primordial black holes ( pbhs ) had come to dominate the energy density of the early universe when oscillations in the axion field began, we show that the relic abundance and expected mass range of the qcd axion would be greatly modified. since the qcd axion is a potential candidate for dark matter ( dm ), we refer to it as the dm axion. we predominantly explore pbhs in the mass range $ ( 10 ^ 6 - 5 \ times 10 ^ 8 ) \, $ g. we investigate the relation between the relic abundance of dm axions and the parameter space of pbhs. we numerically solve the set of boltzmann equations, that governs the cosmological evolution during both radiation and pbh - dominated epochs, providing the bulk energy content of the early universe. we further solve the equation of motion of the dm axion field to obtain its present abundance. alongside non - relativistic production mechanisms, light qcd axions are generated from evaporating pbhs through the hawking mechanism and could make up a fraction of the dark radiation ( dr ). if the qcd axion is ever discovered, it will give us insight into the early universe and probe into the physics of the pbh - dominated era. we estimate the bounds on the model from dr axions produced via pbh evaporation and thermal decoupling, and we account for isocurvature bounds for the period of inflation where the peccei - quinn symmetry is broken. we assess the results obtained against the available cmb data and we comment on the forecasts from gravitational wave searches. we briefly state the consequences of pbh accretion and the uncertainties this may further add to cosmology and astroparticle physics modeling. | arxiv:2209.14307 |
breath is a significant component in singing performance, which is still underresearched in most singing - related music interfaces. in this paper, we present a multimodal system that detects the learner ' s singing pitch and breathing states and provides real - time visual tutoring feedback. specifically, the breath detector is a wearable belt with pressure sensors and flexible fabric. it monitors real - time body movement of the abdomen, back waist, and twin ribs. a breath visualization algorithm is developed to display real - time breath states, together with the singing pitch contours on an interactive score interface. user studies show that our system can help users not only gain deeper breath during singing but also improve pitch accuracy in vocal training, especially for those with some musical background. | arxiv:2202.01439 |
the simplistic but ubiquitous mixing length theory ( mlt ) formalism is used to model convective energy transport within 1d stellar evolution calculations. the formalism relies on the free parameter $ \ alpha _ { \ rm mlt } $, which must be independently calibrated within each stellar evolution program and for any given set of physical assumptions. we present a solar calibration of $ \ alpha _ { \ text { mlt } } $ appropriate for use with the aesopus opacities, which have recently been made available for use with the mesa stellar evolution software. we report a calibrated value of $ \ alpha _ { \ rm mlt } = 1. 931 $ and demonstrate the impact of using an appropriately calibrated value in simulations of a $ 3 m _ { \ odot } $ asymptotic giant branch star. | arxiv:2204.08598 |
big data repositories from online learning platforms such as massive open online courses ( moocs ) represent an unprecedented opportunity to advance research on education at scale and impact a global population of learners. to date, such research has been hindered by poor reproducibility and a lack of replication, largely due to three types of barriers : experimental, inferential, and data. we present a novel system for large - scale computational research, the mooc replication framework ( morf ), to jointly address these barriers. we discuss morf ' s architecture, an open - source platform - as - a - service ( paas ) which includes a simple, flexible software api providing for multiple modes of research ( predictive modeling or production rule analysis ) integrated with a high - performance computing environment. all experiments conducted on morf use executable docker containers which ensure complete reproducibility while allowing for the use of any software or language which can be installed in the linux - based docker container. each experimental artifact is assigned a doi and made publicly available. morf has the potential to accelerate and democratize research on its massive data repository, which currently includes over 200 moocs, as demonstrated by initial research conducted on the platform. we also highlight ways in which morf represents a solution template to a more general class of problems faced by computational researchers in other domains. | arxiv:1801.05236 |
here we present a novel approach to statistical analysis of financial time series. the approach is based on $ n $ - grams frequency dictionaries derived from the quantized market data. such dictionaries are studied by evaluating their information capacity using relative entropy. a specific quantization of ( originally continuous ) financial data is considered : so called binary quantization. possible applications of the proposed technique include market event study with the $ n $ - grams of higher information value. the finite length of the input data presents certain computational and theoretical challenges discussed in the paper. also, some other versions of a quantization are discussed. | arxiv:1308.2732 |
we discuss results for the heavy - light decay constants in the continuum limit of quenched lattice qcd from finite size scaling techniques. we disentangle the simultaneous presence of the different energy scales characterizing heavy - light physics by first performing simulations at the unphysical volume l _ 0 = 0. 4 fm, and then evolving the results towards the infinite volume. we find f _ { bs } = 192 ( 6 ) ( 4 ) mev and f _ { ds } = 240 ( 5 ) ( 5 ) mev. the approach has been developed by the ape group at the university of rome ` ` tor vergata ' '. | arxiv:hep-lat/0310009 |
we investigate the dynamical evolution of a parity - time ( $ \ mathcal { pt } $ ) symmetric extension of the aubry - andr \ ' { e } ( aa ) model, which exhibits the coincidence of a localization - delocalization transition point with a $ \ mathcal { pt } $ symmetry breaking point. one can apply the evolution of the profile of the wave packet and the long - time survival probability to distinguish the localization regimes in the $ \ mathcal { pt } $ symmetric aa model. the results of the mean displacement show that when the system is in the $ \ mathcal { pt } $ symmetry unbroken regime, the wave - packet spreading is ballistic, which is different from that in the $ \ mathcal { pt } $ symmetry broken regime. furthermore, we discuss the distinctive features of the loschmidt echo with the post - quench parameter being localized in different $ \ mathcal { pt } $ symmetric regimes. | arxiv:2101.05666 |
the scope of human consciousness includes states departing from what most of us experience as ordinary wakefulness. these altered states of consciousness constitute a prime opportunity to study how global changes in brain activity relate to different varieties of subjective experience. we consider the problem of explaining how global signatures of altered consciousness arise from the interplay between large - scale connectivity and local dynamical rules that can be traced to known properties of neural tissue. for this purpose, we advocate a research program aimed at bridging the gap between bottom - up generative models of whole - brain activity and the top - down signatures proposed by theories of consciousness. throughout this paper, we define altered states of consciousness, discuss relevant signatures of consciousness observed in brain activity, and introduce whole - brain models to explore the mechanisms of altered consciousness from the bottom - up. we discuss the potential of our proposal in view of the current state of the art, give specific examples of how this research agenda might play out, and emphasise how a systematic investigation of altered states of consciousness via bottom - up modelling may help us better understand the biophysical, informational, and dynamical underpinnings of consciousness. | arxiv:2008.02788 |
in this paper, we use differential privacy as a lens to examine online learning in both full and partial information settings. the differential privacy framework is, at heart, less about privacy and more about algorithmic stability, and thus has found application in domains well beyond those where information security is central. here we develop an algorithmic property called one - step differential stability which facilitates a more refined regret analysis for online learning methods. we show that tools from the differential privacy literature can yield regret bounds for many interesting online learning problems including online convex optimization and online linear optimization. our stability notion is particularly well - suited for deriving first - order regret bounds for follow - the - perturbed - leader algorithms, something that all previous analyses have struggled to achieve. we also generalize the standard max - divergence to obtain a broader class called tsallis max - divergences. these define stronger notions of stability that are useful in deriving bounds in partial information settings such as multi - armed bandits and bandits with experts. | arxiv:1711.10019 |
in [ c. ding, an infinite family of steiner systems $ s ( 2, 4, 2 ^ m ) $ from cyclic codes, { \ em j. combin. des. } 26 ( 2018 ), no. 3, 126 - - 144 ], ding constructed a family of steiner systems $ s ( 2, 4, 2 ^ m ) $ for all $ m \ equiv 2 \ pmod { 4 } $ from a family of extended cyclic codes. the objective of this paper is to present a family of steiner systems $ s ( 2, 4, 2 ^ m ) $ for all $ m \ equiv 0 \ pmod { 4 } $ supported by a family of extended cyclic codes. the main result of this paper complements the previous work of ding, and the results in the two papers will show that there exists a binary extended cyclic code that can support a steiner system $ s ( 2, 4, 2 ^ m ) $ for all even $ m \ geq 4 $. this paper also determines the parameters of other $ 2 $ - designs supported by this family of extended cyclic codes. | arxiv:1904.02310 |
using unitarized chiral perturbation theory methods, we perform a detailed analysis of the $ \ pi \ pi $ scattering poles $ f _ 0 ( 600 ) $ and $ \ rho ( 770 ) $ behaviour when medium effects such as temperature or density drive the system towards chiral symmetry restoration. in the analysis of real poles below threshold, we show that it is crucial to extend properly the unitarized amplitudes so that they match the perturbative adler zeros. our results do not show threshold enhancement effects at finite temperature in the $ f _ 0 ( 600 ) $ channel, which remains as a pole of broad nature. we also implement t = 0 finite density effects related to chiral symmetry restoration, by varying the pole position with the pion decay constant. although this approach takes into account only a limited class of contributions, we reproduce the expected finite density restoration behaviour, which drives the poles towards the real axis, producing threshold enhancement and $ \ pi \ pi $ bound states. we compare our results with several model approaches and discuss the experimental consequences, both in relativistic heavy ion collisions and in $ \ pi \ to \ pi \ pi $ and $ \ gamma \ to \ pi \ pi $ reactions in nuclei. | arxiv:0707.1424 |
one of the factors which may limit the intensity in the fermilab recycler is a fast transverse instability. it develops within a hundred turns and, in certain conditions, may lead to a beam loss. the high rate of the instability suggest that its cause is electron cloud. we studied the phenomena by observing the dynamics of stable and unstable beam, simulating numerically the build - up of the electron cloud, and developed an analytical model of an electron cloud driven instability with the electrons trapped in combined function di - poles. we found that beam motion can be stabilized by a clearing bunch, which confirms the electron cloud nature of the instability. the clearing suggest electron cloud trapping in recycler combined function mag - nets. numerical simulations show that up to 1 % of the particles can be trapped by the magnetic field. since the process of electron cloud build - up is exponential, once trapped this amount of electrons significantly increases the density of the cloud on the next revolution. in a recycler combined function dipole this multi - turn accumulation allows the electron cloud reaching final intensities orders of magnitude greater than in a pure dipole. the estimated resulting instability growth rate of about 30 revolutions and the mode fre - quency of 0. 4 mhz are consistent with experimental observations and agree with the simulation in the pei code. the created instability model allows investigating the beam stability for the future intensity upgrades. | arxiv:1612.03967 |
reconstructing 3ds of hand - object interaction ( hoi ) is a fundamental problem that can find numerous applications. despite recent advances, there is no comprehensive pipeline yet for bimanual class - agnostic interaction reconstruction from a monocular rgb video, where two hands and an unknown object are interacting with each other. previous works tackled the limited hand - object interaction case, where object templates are pre - known or only one hand is involved in the interaction. the bimanual interaction reconstruction exhibits severe occlusions introduced by complex interactions between two hands and an object. to solve this, we first introduce bigs ( bimanual interaction 3d gaussian splatting ), a method that reconstructs 3d gaussians of hands and an unknown object from a monocular video. to robustly obtain object gaussians avoiding severe occlusions, we leverage prior knowledge of pre - trained diffusion model with score distillation sampling ( sds ) loss, to reconstruct unseen object parts. for hand gaussians, we exploit the 3d priors of hand model ( i. e., mano ) and share a single gaussian for two hands to effectively accumulate hand 3d information, given limited views. to further consider the 3d alignment between hands and objects, we include the interacting - subjects optimization step during gaussian optimization. our method achieves the state - of - the - art accuracy on two challenging datasets, in terms of 3d hand pose estimation ( mpjpe ), 3d object reconstruction ( cdh, cdo, f10 ), and rendering quality ( psnr, ssim, lpips ), respectively. | arxiv:2504.09097 |
the excitation of semiconductor quantum dots often involves an attached wetting layer with delocalized single - particle energy eigenstates. these wetting - layer states are usually approximated by ( orthogonalized ) plane waves. we show that this approach is too crude. even for a simple model based on the effective - mass approximation and containing one or a few lens - shaped quantum dots in a rectangular wetting layer, the wetting - layer states typically show a substantially irregular and complex morphology. to quantify this complexity we use concepts from the field of quantum chaos such as spectral analysis of energy levels, amplitude distributions, and localization of energy eigenstates. | arxiv:1904.03981 |
the advancement of future large - scale wireless networks necessitates the development of cost - effective and scalable security solutions. conventional cryptographic methods, due to their computational and key management complexity, are unable to fulfill the low - latency and scalability requirements of these networks. physical layer ( phy ) security has been put forth as a cost - effective alternative to cryptographic mechanisms that can circumvent the need for explicit key exchange between communication devices, owing to the fact that phy security relies on the physics of the signal transmission for providing security. in this work, a space - time - modulated digitally - coded metamaterial ( mtm ) leaky wave antenna ( lwa ) is proposed that can enable phy security by achieving the functionalities of directional modulation ( dm ) using a machine learning - aided branch and bound ( b & b ) optimized coding sequence. from the theoretical perspective, it is first shown that the proposed space - time mtm antenna architecture can achieve dm through both the spatial and spectral manipulation of the orthogonal frequency division multiplexing ( ofdm ) signal received by a user equipment. simulation results are then provided as proof - of - principle, demonstrating the applicability of our approach for achieving dm in various communication settings. to further validate our simulation results, a prototype of the proposed architecture controlled by a field - programmable gate array ( fpga ) is realized, which achieves dm via an optimized coding sequence carried out by the learning - aided branch - and - bound algorithm corresponding to the states of the mtm lwa ' s unit cells. experimental results confirm the theory behind the space - time - modulated mtm lwa in achieving dm, which is observed via both the spectral harmonic patterns and bit error rate ( ber ) measurements. | arxiv:2211.09076 |
w and z bosons will be produced copiously at the lhc proton - proton collider. we study the parton distribution dependence of the total production cross sections and rapidity distributions, paying particular attention to the uncertainties arising from uncertainties in the parton distributions themselves. variations in the gluon, the strong coupling, the sea quarks and the overall normalisation are shown to lead to small but non - negligible variations in the cross section predictions. ultimately, therefore, the measurement of these cross sections will provide a powerful cross check on our knowledge of parton distributions and their evolution. | arxiv:hep-ph/9907231 |
we present a graph - based model for multiple scattering of light in integrated lithium niobate on insulator ( lnoi ) networks, which describes an open network of single - mode integrated waveguides with tunable scattering at the network nodes. we first validate the model at small scale with experimental lnoi resonator devices and show consistent agreement between simulated and measured spectral data. then, the model is used to demonstrate a novel platform for on - chip multiple scattering in large - scale optical networks up to few hundred nodes, with tunable scattering behaviour and tailored disorder. combining our simple graph - based model with material properties of lnoi, this platform creates new opportunities to control randomness in large optical networks. | arxiv:2306.15483 |
after a couple of years of quiescence, the soft gamma repeater sgr 1900 + 14 suddenly reactivated on 18 april 2001, with the emission of a very intense, long and modulated flare, only second in intensity and duration to the 27 august 1998 giant flare. bepposax caught the large flare with its gamma ray burst monitor and with one of the wide field cameras. the wide field cameras also detected x - ray bursting activity shortly before the giant flare. a target of opportunity observation was started only 8 hours after the large flare with the narrow field instruments, composed of two 60 - ks long pointings. these two observations show an x - ray afterglow of the persistent sgr 1900 + 14 source, decaying with time according to a power law of index - 0. 6. | arxiv:astro-ph/0112239 |
we give explicit criteria of solvability for families of linear systems on time scales. we introduce a new method of embedding a time scale into a non - autonomous system of odes. this will be the first step to implementing the structural stability result obtained by one of the co - authors together with v. a. pliss to time scale dynamics. | arxiv:2203.16283 |
we construct cosmological solutions of higher spin gravity in 2 + 1 dimensional de sitter space. we show that a consistent thermodynamics can be obtained for their horizons by demanding appropriate holonomy conditions. this is equivalent to demanding the integrability of the euclidean boundary cft partition function, and reduces to gibbons - hawking thermodynamics in the spin - 2 case. by using a prescription of maldacena, we relate the thermodynamics of these solutions to those of higher spin black holes in ads _ 3. | arxiv:1308.6741 |
we solve the weighted energy problem on the unit circle, by finding the extremal measure and describing its support. applications to polynomial and exponential weights are also included. | arxiv:1307.5454 |
two challenges lie in the facial attractiveness computation research : the lack of true attractiveness labels ( scores ), and the lack of an accurate face representation. in order to address the first challenge, this paper recasts facial attractiveness computation as a label distribution learning ( ldl ) problem rather than a traditional single - label supervised learning task. in this way, the negative influence of the label incomplete problem can be reduced. inspired by the recent promising work in face recognition using deep neural networks to learn effective features, the second challenge is expected to be solved from a deep learning point of view. a very deep residual network is utilized to enable automatic learning of hierarchical aesthetics representation. integrating these two ideas, an end - to - end deep learning framework is established. our approach achieves the best results on a standard benchmark scut - fbp dataset compared with other state - of - the - art work. | arxiv:1609.00496 |
entomology to solve criminal cases is attributed to the book of xi yuan lu ( translated as washing away of wrongs ), written in china in 1248 by song ci (, 1186 – 1249 ), a director of justice, jail and supervision, during the song dynasty. song ci introduced regulations concerning autopsy reports to court, how to protect the evidence in the examining process, and explained why forensic workers must demonstrate impartiality to the public. he devised methods for making antiseptic and for promoting the reappearance of hidden injuries to dead bodies and bones ( using sunlight and vinegar under a red - oil umbrella ) ; for calculating the time of death ( allowing for weather and insect activity ) ; described how to wash and examine the dead body to ascertain the reason for death. at that time the book had described methods for distinguishing between suicide and faked suicide. he wrote the book on forensics stating that all wounds or dead bodies should be examined, not avoided. the book became the first form of literature to help determine the cause of death. in one of song ci ' s accounts ( washing away of wrongs ), the case of a person murdered with a sickle was solved by an investigator who instructed each suspect to bring his sickle to one location. ( he realized it was a sickle by testing various blades on an animal carcass and comparing the wounds. ) flies, attracted by the smell of blood, eventually gathered on a single sickle. in light of this, the owner of that sickle confessed to the murder. the book also described how to distinguish between a drowning ( water in the lungs ) and strangulation ( broken neck cartilage ), and described evidence from examining corpses to determine if a death was caused by murder, suicide or accident. methods from around the world involved saliva and examination of the mouth and tongue to determine innocence or guilt, as a precursor to the polygraph test. in ancient india, some suspects were made to fill their mouths with dried rice and spit it back out. similarly, in ancient china, those accused of a crime would have rice powder placed in their mouths. in ancient middle - eastern cultures, the accused were made to lick hot metal rods briefly. it is thought that these tests had some validity since a guilty person would produce less saliva and thus have a drier mouth ; the accused would be considered guilty if rice was sticking to their mouths in abundance or if their tongues were severely burned due to lack of shielding from saliva. = | https://en.wikipedia.org/wiki/Forensic_science |
goal recognition ( gr ) involves inferring the goals of other vehicles, such as a certain junction exit, which can enable more accurate prediction of their future behaviour. in autonomous driving, vehicles can encounter many different scenarios and the environment may be partially observable due to occlusions. we present a novel gr method named goal recognition with interpretable trees under occlusion ( ogrit ). ogrit uses decision trees learned from vehicle trajectory data to infer the probabilities of a set of generated goals. we demonstrate that ogrit can handle missing data due to occlusions and make inferences across multiple scenarios using the same learned decision trees, while being computationally fast, accurate, interpretable and verifiable. we also release the indo, roundo and openddo datasets of occluded regions used to evaluate ogrit. | arxiv:2206.14163 |
we consider fermion systems on a square lattice with a mass term having a curved domain - wall. similarly to the conventional flat domain - wall fermions, massless and chiral edge states appear on the wall. in the cases of $ s ^ 1 $ and $ s ^ 2 $ domain - walls embedded into flat hypercubic lattices, we find that these edge modes feel gravity through the induced spin or spin $ ^ c $ connections. the gravitational effect is encoded in the dirac eigenvalue spectrum as a gap from zero. in the standard continuum extrapolation of the square lattice, we find a good agreement with the analytic prediction in the continuum theory. we also find that the rotational symmetry of the edge modes is automatically recovered in the continuum limit. | arxiv:2203.03782 |
we introduce a parametrized notion of genericity for delaunay triangulations which, in particular, implies that the delaunay simplices of $ \ delta $ - generic point sets are thick. equipped with this notion, we study the stability of delaunay triangulations under perturbations of the metric and of the vertex positions. we quantify the magnitude of the perturbations under which the delaunay triangulation remains unchanged. | arxiv:1304.2947 |
graph databases have been the subject of significant research and development. problems such as modularity, centrality, alignment, and clustering have been formalized and solved in various application contexts. in this paper, we focus on databases for applications in which graphs have a spatial basis, which we refer to as rigid graphs. nodes in such graphs have preferred positions relative to their graph neighbors. examples of such graphs include abstractions of large biomolecules, functional connectomes of the human brain, and mobile device / sensor communication logs. when analyzing such networks it is important to consider edge lengths ; e. g., when identifying conserved patterns through graph alignment, it is important for conserved edges to have correlated lengths, in addition to topological similarity. in contrast to a large body of work on topological graph alignment, rigid graph alignment simultaneously aligns the network, as well as the underlying structure as characterized by edge lengths. we formulate the problem and present a meta - algorithm based on expectation - maximization that alternately aligns the network and the structure. we demonstrate that our meta - algorithm significantly improves the quality of alignments in target applications, compared to topological or structural aligners alone. we apply rigid graph alignment to functional brain networks derived from 20 subjects drawn from the human connectome project ( hcp ) database, and show over a two - fold increase in quality of alignment over state of the art topological aligners. we evaluate the impact of various parameters associated with input datasets through a study on synthetic graphs, where we fully characterize the performance of our method. our results are broadly applicable to other applications and abstracted networks that can be embedded in metric spaces - - e. g., through spectral embeddings. | arxiv:1908.03201 |
in this work, we address the problem of long - distance navigation for battery electric vehicles ( bevs ), where one or more charging sessions are required to reach the intended destination. we consider the availability and performance of the charging stations to be unknown and stochastic, and develop a combinatorial semi - bandit framework for exploring the road network to learn the parameters of the queue time and charging power distributions. within this framework, we first outline a pre - processing for the road network graph to handle the constrained combinatorial optimization problem in an efficient way. then, for the pre - processed graph, we use a bayesian approach to model the stochastic edge weights, utilizing conjugate priors for the one - parameter exponential and two - parameter gamma distributions, the latter of which is novel to multi - armed bandit literature. finally, we apply combinatorial versions of thompson sampling, bayesucb and epsilon - greedy to the problem. we demonstrate the performance of our framework on long - distance navigation problem instances in country - sized road networks, with simulation experiments in norway, sweden and finland. | arxiv:2301.07156 |
predicting future frames of a video is challenging because it is difficult to learn the uncertainty of the underlying factors influencing their contents. in this paper, we propose a novel video prediction model, which has infinite - dimensional latent variables over the spatio - temporal domain. specifically, we first decompose the video motion and content information, then take a neural stochastic differential equation to predict the temporal motion information, and finally, an image diffusion model autoregressively generates the video frame by conditioning on the predicted motion feature and the previous frame. the better expressiveness and stronger stochasticity learning capability of our model lead to state - of - the - art video prediction performances. as well, our model is able to achieve temporal continuous prediction, i. e., predicting in an unsupervised way the future video frames with an arbitrarily high frame rate. our code is available at \ url { https : / / github. com / xiye20 / stdiffproject }. | arxiv:2312.06486 |
we propose a quantum simulation of a supersymmetric lattice model using atoms trapped in a 1d configuration and interacting through a rydberg dressed potential. the elementary excitations in the model are kinks or ( in a sector with one extra particle ) their superpartners - the skinks. the two are connected by supersymmetry and display identical quantum dynamics. we provide an analytical description of the kink / skink quench dynamics and propose a protocol to prepare and detect these excitations in the quantum simulator. we make a detailed analysis, based on numerical simulation, of the rydberg atom simulator and show that it accurately tracks the dynamics of the supersymmetric model. | arxiv:2005.00607 |
in this paper, we present a hybrid sensorless observer for permanent magnets synchronous machines, with no a priori knowledge of the mechanical dynamics and without the typical assumption of constant or slowly - varying speed. instead, we impose the rotor speed to have a constant ( unknown ) sign and a non - zero magnitude at all times. for the design of the proposed scheme, meaningful lie group formalism is adopted to describe the rotor position as an element of the unit circle. this choice, however, leads to a non - contractible state space, and therefore it introduces topological constraints that complicate the achievement of global / semi - global and robust results. in this respect it is shown that the proposed observer, which employs a clock to periodically reset the estimates, is semi - globally practically asymptotically stable, and thus it improves a continuous - time version designed under the same assumptions. as highlighted in the simulation results, the novel hybrid strategy leads to enhanced transient performance, notably without any modification of the gains employed in the continuous - time solution. these features motivate to augment the observer with a discrete - time identifier, leading to significantly faster rotor flux reconstruction. | arxiv:2002.03635 |
is the forerunner of ibm ' s research division, which today operates research facilities around the world. ultimately, the close relationship between ibm and columbia university was instrumental in the emergence of a new scientific discipline, with columbia offering one of the first academic - credit courses in computer science in 1946. computer science began to be established as a distinct academic discipline in the 1950s and early 1960s. the world ' s first computer science degree program, the cambridge diploma in computer science, began at the university of cambridge computer laboratory in 1953. the first computer science department in the united states was formed at purdue university in 1962. since practical computers became available, many applications of computing have become distinct areas of study in their own rights. = = etymology and scope = = although first proposed in 1956, the term " computer science " appears in a 1959 article in communications of the acm, in which louis fein argues for the creation of a graduate school in computer sciences analogous to the creation of harvard business school in 1921. louis justifies the name by arguing that, like management science, the subject is applied and interdisciplinary in nature, while having the characteristics typical of an academic discipline. his efforts, and those of others such as numerical analyst george forsythe, were rewarded : universities went on to create such departments, starting with purdue in 1962. despite its name, a significant amount of computer science does not involve the study of computers themselves. because of this, several alternative names have been proposed. certain departments of major universities prefer the term computing science, to emphasize precisely that difference. danish scientist peter naur suggested the term datalogy, to reflect the fact that the scientific discipline revolves around data and data treatment, while not necessarily involving computers. the first scientific institution to use the term was the department of datalogy at the university of copenhagen, founded in 1969, with peter naur being the first professor in datalogy. the term is used mainly in the scandinavian countries. an alternative term, also proposed by naur, is data science ; this is now used for a multi - disciplinary field of data analysis, including statistics and databases. in the early days of computing, a number of terms for the practitioners of the field of computing were suggested ( albeit facetiously ) in the communications of the acm — turingineer, turologist, flow - charts - man, applied meta - mathematician, and applied epistemologist. three months later in the same journal, comptologist was suggested, followed next year by hypologist. the term computics has also been suggested | https://en.wikipedia.org/wiki/Computer_science |
we determine the grothendieck ring of finite - dimensional comodules for the free hopf algebra on a matrix coalgebra, and similarly for the free hopf algebra with bijective antipode and other related universal quantum groups. the results turn out to be parallel to those for wang and van daele ' s deformed universal compact quantum groups and bichon ' s generalization of those results to universal cosovereign hopf algebras : in all cases the rings are isomorphic to those of non - commutative polynomials over certain sets, these sets varying from case to case. in most cases we are able to give more precise information about the multiplication table of the grothendieck ring. | arxiv:1006.3464 |
non - deterministic constraint logic ( ncl ) is a simple model of computation based on orientations of a constraint graph with edge weights and vertex demands. ncl captures \ pspace \ xspace and has been a useful tool for proving algorithmic hardness of many puzzles, games, and reconfiguration problems. in particular, its usefulness stems from the fact that it remains \ pspace - complete even under severe restrictions of the weights ( e. g., only edge - weights one and two are needed ) and the structure of the constraint graph ( e. g., planar \ textsc { and / or } \ xspace graphs of bounded bandwidth ). while such restrictions on the structure of constraint graphs do not seem to limit the expressiveness of ncl, the building blocks of the constraint graphs cannot be limited without losing expressiveness : we consider as parameters the number of weight - one edges and the number of weight - two edges of a constraint graph, as well as the number of \ textsc { and } \ xspace or \ textsc { or } \ xspace vertices of an \ textsc { and / or } \ xspace constraint graph. we show that ncl is fixed - parameter tractable ( fpt ) for any of these parameters. in particular, for ncl parameterized by the number of weight - one edges or the number of \ textsc { and } \ xspace vertices, we obtain a linear kernel. it follows that, in a sense, ncl as introduced by hearn and demaine is defined in the most economical way for the purpose of capturing \ pspace. | arxiv:2011.10385 |
we consider difference schemes for the time - fractional diffusion equation with variable coefficients and nonlocal boundary conditions containing real parameters $ \ alpha $, $ \ beta $ and $ \ gamma $. by the method of energy inequalities, for the solution of the difference problem, we obtain a priori estimates, which imply the stability and convergence of these difference schemes. the obtained results are supported by the numerical calculations carried out for some test problems. | arxiv:1405.0030 |
we show open games cover extensive form games with both perfect and imperfect information. doing so forces us to address two current weaknesses in open games : the lack of a notion of player and their agency within open games, and the lack of choice operators. using the former we construct the latter, and these choice operators subsume previous proposed operators for open games, thereby making progress towards a core, canonical and ergonomic calculus of game operators. collectively these innovations increase the level of compositionality of open games, and demonstrate their expressiveness. | arxiv:2105.06763 |
we propose two novel ways of introducing dependence among poisson counts through the use of latent variables in a three levels hierarchical model. marginal distributions of the random variables of interest are poisson with strict stationarity as special case. order - - $ p $ dependence is described in detail for a temporal sequence of random variables, however spatial or spatio - temporal dependencies are also possible. a full bayesian inference of the models is described and performance of the models is illustrated with a numerical analysis of maternal mortality in mexico. extensions to cope with overdispersion are also discussed. | arxiv:2005.10306 |
in radiative transfer, the intensities of radiation from the bounding faces of finite slab are obtained in terms of x - and y - functions of chandrasekhar. those are non linear non homogeneous coupled integral equations. those non linear integral equations are meromorphically extended to the complex plane to get linear non homogeneous coupled integral equations. those linear integral equations are converted to linear singular integral equations with. linear constraints. those singular integral equations are then transformed to non homogeneous riemann hilbert problems. solutions of those riemann hilbert problems are obtained using the theory of linear singular integral equations to decouple those x - and y - functions. new forms of linear non homogeneous decoupled integral equations are derived for x - and y - function separately with new linear constraints. those new decoupled integral equations are transformed into linear singular integral equations to get two new separate non homogeneous riemann hilbert problems and to find solutions in terms of one known n - function and five new unknown functions in complex plane. all five functions are represented in terms of n - functions using the theory of contour integration >. those x - and y - functions are finally expressed in terms of that n - function and also in terms of h - functions of chandrasekhar and of integrals in cauchy principal value sense in the complex plane and real plane. both for conservative and non conservative cases. the h - functions for semi infinite atmosphere are derived as a limiting case from the expression of x - function of finite atmosphere. | arxiv:astro-ph/0702602 |
this paper aims to explore the quasinormal modes ( qnms ) and effective potential profiles of massless and rotating btz black holes within the frameworks of $ f ( \ mathcal { r } ) $ and ricci - inverse ( $ \ mathcal { ri } $ ) modified gravity theories, which, while producing similar space - time structures, exhibit variations due to distinct cosmological constants, $ \ lambda _ m $. we derive wave equations for these black hole perturbations and analyze the behavior of the effective potential $ v _ { \ text { eff } } ( r ) $ under different values of mass $ m $, cosmological constant $ \ lambda _ m $, and modified gravity parameters $ \ alpha _ 1 $, $ \ alpha _ 2 $, $ \ beta _ 1 $, $ \ beta _ 2 $, and $ \ gamma $. the findings indicate that increasing mass and parameter values results in a raised potential barrier, implying stronger confinement of perturbations and impacting black hole stability. incorporating the generalized uncertainty principle, we also study its effect on the thermodynamics of rotating btz black holes, demonstrating how gup modifies black hole radiation, potentially observable in qnm decay rates. additionally, we investigate the motion of particles through null and timelike geodesics in static btz space - time, observing asymptotic behaviors for null geodesics and parameter - dependent shifts in potential for timelike paths. the study concludes that modified gravity parameters significantly influence qnm frequencies and effective potential profiles, offering insights into black hole stability and suggesting that these theoretical predictions may be tested through gravitational wave observations. | arxiv:2412.04513 |
we model non - thermal emission spectrum of the extremely sub - eddington x - ray binary system a0620 - 00. it is believed that this non - thermal emission is produced by a radiatively inefficient " quiescent " accretion onto a stellar - mass black hole present in the system. we post - process grmhd simulations with multiwavelength, fully polarized, relativistic radiative transfer calculations to predict broadband spectra and emission polarization levels for a range of electron models and accretion rates. we find that a model with strong coupling of electrons and ions in the accretion disk and accretion rate of only $ \ dot { m } = 3 \ times10 ^ { - 13 } [ m _ \ odot yr ^ { - 1 } ] $ is able to recover the observed x - ray spectral slope as well as the excess of linear polarization detected in the source in nir / optical bands. our models constrain the spectral properties of a putative relativistic jet produced in this system. in addition we show that the magnetized winds from our hot accretion flow carry away a small fraction of the orbital angular momentum of the binary unable to explain the observed rapid orbital decay of the system. similar to the present grmhd simulations are often used to explain emission from sub - eddington supermassvie black holes in sgr a * or m87 ; the present simulations allow us to test whether some aspects of the quiescent black hole accretion are scale invariant. | arxiv:1910.02416 |
the exact factorization of an electron - nuclear wavefunction [ a. abedi, n. t. maitra, and e. k. u. gross, phys. rev. lett. 105, 123002 ( 2010 ) ] allows us to define the rigorous nuclear time - dependent schr \ " { o } dinger equation ( tdse ) with a time - dependent potential - energy surface ( tdpes ) that fully accounts for the coupling to the electronic motion and drives the nuclear wavepacket dynamics. here, we study whether the propagation of multiple classical trajectories can reproduce the quantum nuclear motion in strong - field processes when their motions are governed by the quantum hamilton - jacobi equation derived by applying bohmian mechanics to this exact nuclear tdse. we demonstrate that multiple classical trajectories propagated by the force from the gradient of the exact tdpes plus the bohmian quantum potential can reproduce the strong - field dissociation dynamics of a one - dimensional model of the h $ _ 2 ^ + $ molecule. our results show that the force from the bohmian quantum potential plays a non - negligible role in yielding quantum nuclear dynamics in the strong - field process studied here, where ionization and / or splitting of nuclear probability density occurs. | arxiv:1607.04854 |
we develop a numerical approach for computing the additive, multiplicative and compressive convolution operations from free probability theory. we utilize the regularity properties of free convolution to identify ( pairs of ) ` admissible ' measures whose convolution results in a so - called ` invertible measure ' which is either a smoothly - decaying measure supported on the entire real line ( such as the gaussian ) or square - root decaying measure supported on a compact interval ( such as the semi - circle ). this class of measures is important because these measures along with their cauchy transforms can be accurately represented via a fourier or chebyshev series expansion, respectively. thus, knowledge of the functional inverse of their cauchy transform suffices for numerically recovering the invertible measure via a non - standard yet well - behaved vandermonde system of equations. we describe explicit algorithms for computing the inverse cauchy transform alluded to and recovering the associated measure with spectral accuracy. convergence is guaranteed under broad assumptions on the input measures. | arxiv:1203.1958 |
a sequential solver for differential - algebraic equations with embedded optimization criteria ( daeos ) was developed to take advantage of the theoretical work done by deussen et al. solvers of this type separate the optimization problem from the differential equation and solve each individually. the new solver relies on the reduction of a daeo to a sequence of differential inclusions separated by jump events. these jump events occur when the global solution to the optimization problem jumps to a new value. without explicit treatment, these events will reduce the order of convergence of the integration step to one. the solver implements a " local optimizer tracking " procedure to detect and correct these jump events. local optimizer tracking is much less expensive than running a deterministic global optimizer at every time step. this preserves the order of convergence of the integrator component without sacrificing performance to perform deterministic global optimization at every time step. the newly developed solver produces correct solutions to daeos and runs much faster than sequential daeo solvers that rely only on global optimization. | arxiv:2410.15963 |
the noise - enhanced trapping is a surprising phenomenon that has already been studied in chaotic scattering problems where the noise affects the physical variables but not the parameters of the system. following this research, in this work we provide strong numerical evidence to show that an additional mechanism that enhances the trapping arises when the noise influences the energy of the system. for this purpose, we have included a source of gaussian white noise in the h \ ' enon - heiles system, which is a paradigmatic example of open hamiltonian system. for a particular value of the noise intensity, some trajectories decrease their energy due to the stochastic fluctuations. this drop in energy allows the particles to spend very long transients in the scattering region, increasing their average escape times. this result, together with the previously studied mechanisms, points out the generality of the noise - enhanced trapping in chaotic scattering problems. | arxiv:2105.05746 |
within our present knowledge, the tau is the heaviest lepton and the only one decaying into hadrons, a fact that makes it the source of a very rich phenomenology. it represents the third family of leptons in the standard model, a feature that helps its classification but whose real meaning is not asserted yet. the tau lepton provides : i ) a clean and unique environment to study both the hadronization of qcd currents, in an energy region populated by resonances, and the phenomenological determination of relevant parameters of the model ; ii ) together with the muon, they have a very constrained flavour dynamics ( in the absence of neutrino masses ) due to an accidental global symmetry of the standard model. in consequence, the tau lepton brings an excellent benchmark for the study of qcd at low energies and, at the same time, for the search of new physics. | arxiv:2203.05310 |
in this paper, we study the hyperbolic geometry of noncommutative balls generated by the joint operator radius $ \ omega _ \ rho $, $ \ rho \ in ( 0, \ infty ] $, for $ n $ - tuples of bounded linear operators on a hilbert space. in particular, $ \ omega _ 1 $ is the operator norm, $ \ omega _ 2 $ is the joint numerical radius, and $ \ omega _ \ infty $ is the joint spectral radius. we provide mapping theorems, von neumann inequalities, and schwarz type lemmas for free holomorphic functions on noncommutative balls, with respect to the hyperbolic metric $ \ delta _ \ rho $, the carath \ ' eodory metric $ d _ k $, and the joint operator radius $ \ omega _ \ rho $. | arxiv:0911.5489 |
we present iterative monte carlo algorithm for which the temperature variable is attracted by a critical point. the algorithm combines techniques of single histogram reweighting and linear filtering. the 2d ising model of ferromagnet is studied numerically as an illustration. in that case, the iterations uncovered stationary regime with invariant probability distribution function of temperature which is peaked nearly the pseudocritical temperature of specific heat. the sequence of generated temperatures is analyzed in terms of stochastic autoregressive model. the error of histogram reweighting can be better understood within the suggested model. the presented model yields a simple relation, connecting variance of pseudocritical temperature and parameter of linear filtering. | arxiv:cond-mat/0401178 |
language models ( lms ) have been argued to overlap substantially with human beings in grammaticality judgment tasks. but when humans systematically make errors in language processing, should we expect lms to behave like cognitive models of language and mimic human behavior? we answer this question by investigating lms ' more subtle judgments associated with " language illusions " - - sentences that are vague in meaning, implausible, or ungrammatical but receive unexpectedly high acceptability judgments by humans. we looked at three illusions : the comparative illusion ( e. g. " more people have been to russia than i have " ), the depth - charge illusion ( e. g. " no head injury is too trivial to be ignored " ), and the negative polarity item ( npi ) illusion ( e. g. " the hunter who no villager believed to be trustworthy will ever shoot a bear " ). we found that probabilities represented by lms were more likely to align with human judgments of being " tricked " by the npi illusion which examines a structural dependency, compared to the comparative and the depth - charge illusions which require sophisticated semantic understanding. no single lm or metric yielded results that are entirely consistent with human behavior. ultimately, we show that lms are limited both in their construal as cognitive models of human language processing and in their capacity to recognize nuanced but critical information in complicated language materials. | arxiv:2311.01386 |
let $ \ chi $ be a dirichlet character modulo $ p $, a prime. in applications, one often needs estimates for short sums involving $ \ chi $. one such estimate is the family of bounds known as \ emph { burgess ' bound }. in this paper, we explore several minor adjustments one can make to the work of enrique trevi \ ~ no on explicit versions of burgess ' bound. for an application, we investigate the problem of the existence of a $ k $ th power non - residue modulo $ p $ which is less than $ p ^ \ alpha $ for several fixed $ \ alpha $. we also provide a quick improvement to the conductor bounds for norm - euclidean cyclic fields. | arxiv:1910.13669 |
our study of the adsorption of oxygen molecules on individual semiconductiong single - walled carbon nanotubes at ambient conditions reveals that the adsorption is physisorption, that the resistance without o2 increases by ~ two orders of magnitude as compared to that with o2, and that the sensitive response is due to the pinning of the fermi level near the top of the valence band of the tube resulting from impurity states of o2 appearing above the valence band. | arxiv:cond-mat/0502012 |
in this paper, we propose a novel self - supervised transfer learning method called distribution matching ( dm ), which drives the representation distribution toward a predefined reference distribution while preserving augmentation invariance. the design of dm results in a learned representation space that is intuitively structured and offers easily interpretable hyperparameters. experimental results across multiple real - world datasets and evaluation metrics demonstrate that dm performs competitively on target classification tasks compared to existing self - supervised transfer learning methods. additionally, we provide robust theoretical guarantees for dm, including a population theorem and an end - to - end sample theorem. the population theorem bridges the gap between the self - supervised learning task and target classification accuracy, while the sample theorem shows that, even with a limited number of samples from the target domain, dm can deliver exceptional classification performance, provided the unlabeled sample size is sufficiently large. | arxiv:2502.14424 |
the phase diagram of hard helices differs from its hard rods counterpart by the presence of chiral " screw " phases stemming from the characteristic helical shape, in addition to the conventional liquid crystal phases also found for rod - like particles. using extensive monte carlo and molecular dynamics simulations, we study the effect of the addition of a short - range attractive tail representing solvent - induced interactions to a fraction of the sites forming the hard helices, ranging from a single - site attraction to fully attractive helices for a specific helical shape. different temperature regimes exist for different fractions of the attractive sites, as assessed in terms of the relative boyle temperatures, that are found to be rather insensitive to the specific shape of the helical particle. the temperature range probed by the present study is well above the corresponding boyle temperatures, with the phase behaviour still mainly entropically dominated and with the existence and location of the various liquid crystal phases only marginally affected. the pressure in the equation of state is found to decrease upon increasing the fraction of attractive beads and / or on lowering the temperature at fixed volume fraction, as expected on physical grounds. all screw phases are found to be stable within the considered range of temperatures with the smectic phase becoming more stable on lowering the temperature. by contrast, the location of the transition lines do not display a simple dependence on the fraction of attractive beads in the considered range of temperatures. | arxiv:2310.05545 |
in [ arxiv : 2409. 00161v1 ( 2024 ) ] cavendish et al. raise three criticisms against our time of arrival proposal [ l. maccone and k. sacha, phys. rev. lett. 124, 110402 ( 2020 ) ]. here we show that all three criticisms are without merit. one of them is founded on a logical mistake. | arxiv:2501.10416 |
the results on elliptic flow in sqrt ( s ) = 2. 76 tev pb + pb collisions at the large hadron collider ( lhc ) reported by the alice collaboration are remarkably similar to those for sqrt ( s ) = 200 gev gold - gold collisions at the relativistic heavy ion collider ( rhic ). this result is surprising, given the expected longer lifetime of the system at the higher collision energies. we show that it is nevertheless consistent with 3 + 1 dimensional viscous event - by - event hydrodynamic calculations, and demonstrate that elliptic flow at both rhic and lhc is built up mostly within the first 5 fm / c of the evolution. we conclude that an " almost perfect liquid " is produced in heavy - ion collisions at the lhc. furthermore, we present predictions for triangular flow as a function of transverse momentum for different centralities. | arxiv:1102.0575 |
millimeter - wave ( mmwave ) radar - based gesture recognition is gaining attention as a key technology to enable intuitive human - machine interaction. nevertheless, the significant challenge lies in obtaining large - scale, high - quality mmwave gesture datasets. to tackle this problem, we present iradar, a novel cross - modal gesture recognition framework that employs inertial measurement unit ( imu ) data to synthesize the radar signals generated by the corresponding gestures. the key idea is to exploit the imu signals, which are commonly available in contemporary wearable devices, to synthesize the radar signals that would be produced if the same gesture was performed in front of a mmwave radar. however, several technical obstacles must be overcome due to the differences between mmwave and imu signals, the noisy gesture sensing of mmwave radar, and the dynamics of human gestures. firstly, we develop a method for processing imu and mmwave data to extract critical gesture features. secondly, we propose a diffusion - based imu - to - radar translation model that accurately transforms imu data into mmwave data. lastly, we devise a novel transformer model to enhance gesture recognition performance. we thoroughly evaluate iradar, involving 18 gestures and 30 subjects in three scenarios, using five wearable devices. experimental results demonstrate that iradar consistently achieves 99. 82 % top - 3 accuracy across diverse scenarios. | arxiv:2412.15980 |
we show that, if l is an extremal type ii lattice of rank 40 or 80, then l is generated by its vectors of norm min ( l ) + 2. this sharpens earlier results of ozeki, and the second author and abel, which showed that such lattices l are generated by their vectors of norms min ( l ) and min ( l ) + 2. | arxiv:0905.4306 |
we analyse the azimuthal decorrelation of mueller - navelet dijets produced in the collisions at tevatron energies using a bfkl framework which incorporates dominant subleading effects. we show that these effects significantly reduce the decorrelation yet they are still insufficient to give satisfactory description of experimental data. however a good description of the data is obtained after incorporating within formalism the effective rapidity defined by del duca and schmidt. | arxiv:hep-ph/0105039 |
the consensus protocol is a critical component of distributed ledgers and blockchains. achieving consensus over a decentralized network poses challenges to transaction finality and performance. currently, the highest - performing consensus algorithms are speculative bft algorithms, which, however, compromise on the transaction finality guarantees offered by their non - speculative counterparts. in this paper, we introduce albatross, a proof - of - stake ( pos ) blockchain consensus algorithm that aims to combine the best of both worlds. at its heart, albatross is a high - performing, speculative bft algorithm that offers strong probabilistic finality. we complement this by periodically guaranteeing finality through the tendermint protocol. we prove our protocol to be secure under standard bft assumptions and analyze its performance both on a theoretical and practical level. for that, we provide an open - source rust implementation of albatross. our real - world measurements support that our protocol has a performance close to the theoretical maximum for single - chain proof - of - stake consensus algorithms. | arxiv:1903.01589 |
the possibility of electroweak baryogenesis is considered within the framework of a left - right supersymmetric model. it is shown that for a range of parameters the large sneutrino vev required for parity breaking varies at the electroweak phase transition leading to a production of baryons. the resulting baryon to entropy ratio is approximated to be $ { n _ b \ over s } \ sim \ alpha 0. 7 \ times10 ^ { - 8 } $, where $ \ alpha $ is the angle that the phase of sneutrino vev changes at the electroweak phase transition. | arxiv:hep-ph/9810305 |
we present a theory to obtain the pressure tensor for a class of non - ideal multicomponent lattice boltzmann models, thus extending the theory presented by shan ( x. shan, phys. rev. e 77, 066702 ( 2008 ) ) for single component fluids. we obtain the correct form of the pressure tensor directly on the lattice and the resulting equilibrium properties are shown to agree very well with those measured from numerical simulations. results are compared with those of alternative theories. | arxiv:1305.2547 |
in wireless caching networks, a user generally has a concrete purpose of consuming contents in a certain preferred category, and requests multiple contents in sequence. while most existing research on wireless caching and delivery has focused only on one - shot requests, the popularity distribution of contents requested consecutively is definitely different from the one - shot request and has been not considered. also, especially from the perspective of the service provider, it is advantageous for users to consume as many contents as possible. thus, this paper proposes two cache allocation policies for categorized contents and consecutive user demands, which maximize 1 ) the cache hit rate and 2 ) the number of consecutive content consumption, respectively. numerical results show how categorized contents and consecutive content requests have impacts on the cache allocation. | arxiv:2002.06254 |
we observe and study new non - linear global space - time symmetries of the full ghost + matter action of rns superstring theory. we show that these surprising new symmetries are generated by the special worldsheet currents ( vertex operators ) of rns superstring theory, violating the equivalence of superconformal ghost pictures. we review the questions of brst invariance and non - triviality of picture - dependent vertex operators and show their relation to hidden space - time symmetries and hidden space - time dimensions. in particular, we relate the space - time transformations, induced by the picture - dependent currents, to the symmetries observed in the 2t physics approach. | arxiv:hep-th/0701044 |
we propose a new approximation scheme to obtain analytic expressions for the bound state energies and eigenfunctions of yukawa like potentials. the predicted energies are in excellent agreement with the accurate numerical values reported in the literature. | arxiv:quant-ph/0507098 |
we employ techniques from topological data analysis to model sensor networks. our approach to sensor integration uses the topological method of sheaves over cell complexes. the internal consistency of data from individual sensors is determined by a set of consistency functions assigned to elements of the complex. using these functions we determine, for any collection of data, the unique set of maximal sections of consistent data received from the sensors. we offer a proof for the existence and uniqueness of these sections and illustrate the ideas with examples. | arxiv:1612.00397 |
we study evolution of entanglement of two two - level atoms placed inside a multilayered microsphere. we show that due to inhomogeneity of the field modes this entanglement essentially depends on the atomic positions ( asymmetrical entanglement ) and also on the detuning between the atomic transitions and field frequencies. the robust and complete entanglement can be achieved even in the resonant case when the atoms have different effective coupling constants, and it can be extended in time if the detuning is large enough. we study analytically the lossless case and estimate numerically the effect of dissipative processes. | arxiv:quant-ph/0603198 |
we show that string algebras are ` homologically tame ' in the following sense : first, the syzygies of arbitrary representations of a finite dimensional string algebra $ \ lambda $ are direct sums of cyclic representations, and the left finitistic dimensions, both little and big, of $ \ lambda $ can be computed from a finite set of cyclic left ideals contained in the jacobson radical. second, our main result shows that the functorial finiteness status of the full subcategory $ \ cal p $ consisting of the finitely generated left $ \ lambda $ - modules of finite projective dimension is completely determined by a finite number of, possibly infinite dimensional, string modules - - one for each simple $ \ lambda $ - module - - which are algorithmically constructible from quiver and relations of $ \ lambda $. namely, $ \ cal p $ is contravariantly finite in $ \ lambda $ - mod precisely when all of these string modules are finite dimensional, in which case they coincide with the minimal $ \ cal p $ - approximations of the corresponding simple modules. yet, even when $ \ cal p $ fails to be contravariantly finite, these ` characteristic ' string modules encode, in an accessible format, all desirable homological information about $ \ lambda $ - mod. | arxiv:math/0111001 |
the dynamics near a hyperbolic point in phase space is modelled by an inverted harmonic oscillator. we investigate the effect of the classical instability on the open quantum dynamics of the oscillator, introduced through the interaction with a thermal bath, using both the survival probability function and the rate of von neumann entropy increase, for large times. in this parameter range we prove, using influence functional techniques, that the survival probability function decreases exponentially at a rate, k ', depending not only on the measure of instability in the model but also on the strength of interaction with the environment. we also show that k ' determines the rate of von neumann entropy increase and that this result is independent of the temperature of the environment. this generalises earlier results which are valid in the limit of vanishing dissipation. the validity of inferring similar rates of survival probability decrease and entropy increase for quantum chaotic systems is also discussed. | arxiv:chao-dyn/9807009 |
we describe instrumentation designed to perform millimeter - wave conductivity measurements in pulsed high magnetic fields at low temperatures. the main component of this system is an entirely non - metallic microwave resonator. the resonator utilizes periodic dielectric arrays ( photonic bandgap structures ) to confine the radiation, such that the resonant modes have a high q - factor, and the system possesses sufficient sensitivity to measure small samples within the duration of a magnet pulse. as well as measuring the sample conductivity to probe orbital physics in metallic systems, this technique can detect the sample permittivity and permeability allowing measurement of spin physics in insulating systems. we demonstrate the system performance in pulsed magnetic fields with both electron paramagnetic resonance experiments and conductivity measurements of correlated electron systems. | arxiv:cond-mat/0606476 |
a rotorcraft - based unmanned aerial vehicle exhibits more complex properties compared to its full - size counterparts due to its increased sensitivity to control inputs and disturbances and higher bandwidth of its dynamics. as an aerial vehicle with vertical take - off and landing capability, the helicopter specifically poses a difficult problem of transition between forward flight and unstable hover and vice versa. the lpv control technique explicitly takes into account the change in performance due to the real - time parameter variations. the technique therefore theoretically guarantees the performance and robustness over the entire operating envelope. in this study, we investigate a new approach implementing model identification for use in the lpv control framework. the identification scheme employs recursive least square technique implemented on the lpv system represented by dynamics of helicopter during a transition. the airspeed as the scheduling of parameter trajectory is not assumed to vary slowly. the exclusion of slow parameter change requirement allows for the application of the algorithm for aggressive maneuvering capability without the need of expensive computation. the technique is tested numerically and will be validated in the autonomous flight of a small scale helicopter. | arxiv:0806.4021 |
included mines engineering and physical mathematical state - of - the - art knowledge from europe. then came the 19th century and lack of political stability. the universities founded under spanish rule were closed and reopened and the engineering teaching tradition was lost ; the university of mexico, university of guadalajara and university of merida suffered this. then the liberal rule created the arts and handcraft schools were opened without the same success as the universities. in the 20th century and with the success of the mexican revolution some of the old colleges were reopened and the old arts and handcraft schools were joined to the new universities. in 1936 the national polytechnic institute of mexico was created as an educational alternative for workers ' sons and their families. a short time later the regional institutes of technology were founded as a branch of the polytechnic institute in a few states of the republic, though most of them do not have any university in their own territory. right now the regional institutes of technology have been merged into one single entity labeled as mexican national technological institute. the national polytechnic institute is the ensign university of the mexican federal government on engineering education. = = = united states = = = the first professional degree in engineering is a bachelor ' s degree with few exceptions. interest in engineering has grown since 1999 ; the number of bachelor ' s degrees issued has increased by 20 %. most bachelor ' s degree engineering programs are four years long and require about two years of core courses followed by two years of specialized discipline specific courses. this is where a typical engineering student would learn mathematics ( single - and multi - variable calculus and elementary differential equations ), general chemistry, english composition, general and modern physics, computer science ( typically programming ), and introductory engineering in several areas that are required for a satisfactory engineering background and to be successful in their program of choice. several courses in social sciences or humanities are often also required, but are commonly elective courses from a broad choice. required common engineering courses typically include engineering drawing / computer - aided - design, materials engineering, statics and dynamics, strength of materials, basic circuits, thermodynamics, fluid mechanics, and perhaps some systems or industrial engineering. the science and engineering courses include lecture and laboratory education, either in the same course ( s ) or in separate courses. however, some professors and educators believe that engineering programs should change to focus more on professional engineering practice, and engineering courses should be taught more by professional engineering practitioners and not by engineering researchers. many engineering degree programs admit students directly to a specialization as a first - year, but those which don ' t often | https://en.wikipedia.org/wiki/Engineering_education |
we study the question whether properties like local / weak almost squareness and local octahedrality pass down from an absolute sum $ x \ oplus _ f y $ to the summands $ x $ and $ y $. | arxiv:1705.06610 |
it is known that in quantum theory, measurements may suppress hamiltonian dynamics of a system. a famous example is the ` quantum zeno effect '. this is the phenomena that if one repeats the measurements many times asking whether the system is in the same state as the one at the initial time until the fixed measurement time, then survival probability tends to 1 by taking the measurement interval to 0. this is the case for fixed measurement time. it is known that if one takes measurement time infinite at appropriate scaling, ` quantum zeno effect ' does not occur and the effect of hamiltonian dynamics emerges ( facchi and ligabo 2017 ). in the present paper, we consider the long time repeated measurements and the dynamics of quantum many body systems in the scaling where the effect of measurements and dynamics are balanced. we show that the stochastic process, called symmetric simple exclusion process ( ssep ), is obtained from the repeated and long time measurements of configuration of particles in finite lattice fermion systems. the emerging stochastic process is independent of potential and interaction of the underlying hamiltonian of the system. | arxiv:2007.13940 |
rectification and diffusion of non - interacting self - propelled particles is numerically investigated in a two - dimensional corrugated channel. from numerical simulations, we obtain the average velocity and the effective diffusion coefficient. it is found that the self - propelled particles can be rectified by the self - propelled velocity. there exist optimal values of the parameters ( the self - propelled velocity, the translational diffusion constant, and the height of the potential ) at which the average velocity takes its maximal value. there exists an optimal translational diffusion at which the effective diffusion constant is maximal. the self - propelled velocity can strongly increase the effective diffusion, while the large rotational diffusion rate can strongly suppress the effective diffusion. | arxiv:1407.7089 |
we study vertex cut and flow sparsifiers that were recently introduced by moitra, and leighton and moitra. we improve and generalize their results. we give a new polynomial - time algorithm for constructing o ( log k / log log k ) cut and flow sparsifiers, matching the best existential upper bound on the quality of a sparsifier, and improving the previous algorithmic upper bound of o ( log ^ 2 k / log log k ). we show that flow sparsifiers can be obtained from linear operators approximating minimum metric extensions. we introduce the notion of ( linear ) metric extension operators, prove that they exist, and give an exact polynomial - time algorithm for finding optimal operators. we then establish a direct connection between flow and cut sparsifiers and lipschitz extendability of maps in banach spaces, a notion studied in functional analysis since 1930s. using this connection, we prove a lower bound of omega ( sqrt { log k / log log k } ) for flow sparsifiers and a lower bound of omega ( sqrt { log k } / log log k ) for cut sparsifiers. we show that if a certain open question posed by ball in 1992 has a positive answer, then there exist \ tilde o ( sqrt { log k } ) cut sparsifiers. on the other hand, any lower bound on cut sparsifiers better than \ tilde omega ( sqrt { log k } ) would imply a negative answer to this question. | arxiv:1006.4607 |
we consider the rupture dynamics of a homopolymer chain pulled at one end at a constant loading rate. our model of the breakable polymer is related to the rouse chain, with the only difference that the interaction between the monomers is described by the morse potential instead of the harmonic one, and thus allows for mechanical failure. we show that in the experimentally relevant domain of parameters the dependence of the most probable rupture force on the chain length may be non - monotonic, so that the medium - length chains break easier than the short and the long ones. the qualitative theory of the effect is presented. | arxiv:0902.1424 |
when xps analyses are performed on insulator surfaces, shift and deformation of spectra peaks typically take place due to the surface charging. to achieve reliable xps measurements, neutralization techniques have been widely adopted but their effectiveness are still limited, and thus, new neutralization technologies are urgently needed. here, stable xps spectra in which all the peaks undergo a reduced and nearly constant shift without significant deformation and broadening were obtained by introducing the uv light irradiation, implying that the introduction of the uv light can not only greatly attenuate the strength but also significantly improve both the temporal stability and the spatial uniformity of the surface charging during xps measurements. this phenomenon, referred to as uv - assisted neutralization in this article, was found as effective as the most commonly used dual beam charge neutralization. further observations show that the suppression of the charging issue comes from the adsorption of the uv - excited photoelectrons onto the x - ray irradiation region. this neutralization method, combined with the binding energy referencing, can be expected to become a promising alternative technique for solving the charging issues in xps measurements. | arxiv:2409.00663 |
here we propose four - terminal molecular devices as functional logic gates ( and, nor and xor, respectively ). such devices are composed of single organic molecule connected to gold electrodes and located in between gate terminals. specifically, the operation principle of molecular logic gates is discussed in detail. the input signal of the gate voltages can modify the output signal of the current carried through the device ( for concrete value of applied source - drain bias ) to simulate classical ( boolean ) logical operations. calculational scheme for current - voltage ( i - v ) characteristics is based on the landauer transport theory, where molecule is described with the help of tight - binding model, gold electrodes are treated within an effective newns - anderson theory and gate terminals are modeled as capacitor plates. | arxiv:cond-mat/0309666 |
due to the fourth industrial revolution, industrial applications make use of the progress in communication and embedded devices. this allows industrial users to increase efficiency and manageability while reducing cost and effort. furthermore, the fourth industrial revolution, creating the so - called industry 4. 0, opens a variety of novel use and business cases in the industrial environment. however, this progress comes at the cost of an enlarged attack surface of industrial companies. operational networks that have previously been phyiscally separated from public networks are now connected in order to make use of new communication capabilites. this motivates the need for industrial intrusion detection solutions that are compatible to the long - term operation machines in industry as well as the heterogeneous and fast - changing networks. in this work, process data is analysed. the data is created and monitored on real - world hardware. after a set up phase, attacks are introduced into the systems that influence the process behaviour. a time series - based anomaly detection approach, the matrix profiles, are adapted to the specific needs and applied to the intrusion detection. the results indicate an applicability of these methods to detect attacks in the process behaviour. furthermore, they are easily integrated into existing process environments. additionally, one - class classifiers one - class support vector machines and isolation forest are applied to the data without a notion of timing. while matrix profiles perform well in terms of creating and visualising results, the one - class classifiers perform poorly. | arxiv:1909.03730 |
we propose an adaptation of the notion of scaling symmetries for the case of lie - hamilton systems, allowing their subsequent reduction to contact lie systems. as an illustration of the procedure, time - dependent frequency oscillators and time - dependent thermodynamic systems are analyzed from this point of view. the formalism provides a novel method for constructing contact lie systems on the three - dimensional sphere, derived from recently established lie - hamilton systems arising from the fundamental four - dimensional representation of the symplectic lie algebra $ \ mathfrak { sp } ( 4, \ mathbb { r } ) $. it is shown that these systems are a particular case of a larger hierarchy of contact lie systems on a special class of three - dimensional homogeneous spaces, namely the cayley - klein spaces. these include riemannian spaces ( sphere, hyperbolic and euclidean spaces ), pseudo - riemannian spaces ( anti - de sitter, de sitter and minkowski spacetimes ), as well as newtonian or non - relativistic spacetimes. under certain topological conditions, some of these systems retrieve well - known two - dimensional lie - hamilton systems through a curvature - dependent reduction. | arxiv:2503.20558 |
we introduce a semiparametric latent space model for analyzing longitudinal network data. the model consists of a static latent space component and a time - varying node - specific baseline component. we develop a semiparametric efficient score equation for the latent space parameter by adjusting for the baseline nuisance component. estimation is accomplished through a one - step update estimator and an appropriately penalized maximum likelihood estimator. we derive oracle error bounds for the two estimators and address identifiability concerns from a quotient manifold perspective. our approach is demonstrated using the new york citi bike dataset. | arxiv:2308.12227 |
reliably predicting future occupancy of highly dynamic urban environments is an important precursor for safe autonomous navigation. common challenges in the prediction include forecasting the relative position of other vehicles, modelling the dynamics of vehicles subjected to different traffic conditions, and vanishing surrounding objects. to tackle these challenges, we propose a spatio - temporal prediction network pipeline that takes the past information from the environment and semantic labels separately for generating future occupancy predictions. compared to the current sota, our approach predicts occupancy for a longer horizon of 3 seconds and in a relatively complex environment from the nuscenes dataset. our experimental results demonstrate the ability of spatio - temporal networks to understand scene dynamics without the need for hd - maps and explicit modeling dynamic objects. we publicly release our occupancy grid dataset based on nuscenes to support further research. | arxiv:2205.03212 |
atrial fibrillation ( af ) is the most common cardiac arrhythmia in human beings, and is associated with significant morbidity and mortality. the current standard of care includes interventional catheter ablation in selected patients, but the success rate is limited. the major limitation of the current approach to af is the lack of fundamental understanding of its underlying mechanism. specifically, it remains unclear whether human af dynamics are a deterministic or a stochastic process. here we assess for determinism in human af by evaluating the properties of the symbolic representation of intracardiac electrical recordings obtained from patients. specifically, we evaluate ( a ) the number of the missing ordinal patterns, ( b ) the rate of missing ordinal pattern decay for increased length of the time series, and ( c ) the causal - entropy complexity plane of the bandt - pompe symbolic representation. when used together, these are powerful tools to detect determinism, even in the presence of experimental noise and brief time series. | arxiv:1802.01496 |
we prove effective equidistribution of non - closed horocycles in the unit tangent bundle of infinite - volume geometrically finite hyperbolic surfaces. | arxiv:1903.04290 |
dense particulate suspensions can not only increase their viscosity and shear thicken under external forcing, but also jam into a solid - like state that is fully reversible when the force is removed. an impact on the surface of a dense suspension can trigger this jamming process by generating a shear front that propagates into the bulk of the system. tracking and visualizing such a front is difficult because suspensions are optically opaque and the front can propagate as fast as several meters per second. recently, high - speed ultrasound imaging has been used to overcome this problem and extract two - dimensional sections of the flow field associated with jamming front propagation. here we extend this method to reconstruct the three - dimensional flow field. this enables us to investigate the evolution of jamming fronts for which axisymmetry cannot be assumed, such as impact at angles tilted away from the normal to the free surface of the suspension. we find that sufficiently far from solid boundaries the resulting flow field is approximately identical to that generated by normal impact, but rotated and aligned with the angle of impact. however, once the front approaches the solid boundary at the bottom of the container, it generates a squeeze flow that deforms the front profile and causes jamming to proceed in a non - axisymmetric manner. | arxiv:1810.11161 |
neural language models trained with a predictive or masked objective have proven successful at capturing short and long distance syntactic dependencies. here, we focus on verb argument structure in german, which has the interesting property that verb arguments may appear in a relatively free order in subordinate clauses. therefore, checking that the verb argument structure is correct cannot be done in a strictly sequential fashion, but rather requires to keep track of the arguments ' cases irrespective of their orders. we introduce a new probing methodology based on minimal variation sets and show that both transformers and lstm achieve a score substantially better than chance on this test. as humans, they also show graded judgments preferring canonical word orders and plausible case assignments. however, we also found unexpected discrepancies in the strength of these effects, the lstms having difficulties rejecting ungrammatical sentences containing frequent argument structure types ( double nominatives ), and the transformers tending to overgeneralize, accepting some infrequent word orders or implausible sentences that humans barely accept. | arxiv:1912.00239 |
hades is the only operating dielectron spectrometer in the energy regime 1 - 2 agev. the physics program aims at a systematic investigation of dielectron production in heavy ion as well as elementary and pion - induced reactions. this contribution highlights recent results on electron pair production in c12 + c12 collisions at an incident energy of 2 agev with hades. the measured pair production probabilities span over five orders of magnitude. dalitz decays of pi0 and eta account for all the yield up to 0. 15 gev / c2, but for only about 50 % above this invariant mass. the excess yield compared to the hadronic cocktail between the pi0 - dalitz and the rho / omega invariant - mass region is in agreement with the former dls result if one assumes that it scales with beam energy like pion production. preliminary results from c12 + c12 collisions at an incident energy of 1 agev support this scenario. | arxiv:0710.3274 |
stage of social practice, and a feature of mass innovation, joint innovation, and open innovation. shape, innovation 2. 0 mode is gradually emerging to the attention of the scientific community and society. = = mobile communication industry = = source : 0g : an early cellular mobile phone technology emerged in the 1970s. at this time, although briefcase - type mobile phones have appeared, they still generally need to be installed in a car or truck. ptt : push to talk mts : mobile telephone system imts : improved mobile telephone service amts : advanced mobile telephone system 0. 5g : a group of technologies improving basic 0g technical characteristics. autotel / palm : autotel or palm ( public automated land mobile ) arp : autoradiopuhelin, car radio phone 1g : refers to the first generation of wireless telephone technology, namely cellular portable wireless telephone. introduced in the 1980s are analog cellular portable radiotelephone standards. nmt : nordic mobile telephone amps : advanced mobile phone system tacs : total access communication system ( tacs : total access communication system ) is the european version of amps jtags : japan total access communication system 2g : second - generation wireless telephone based on digital technology. 2g networks are only for voice communications, except that some standards can also use sms messages as a form of data transmission. gsm : global system for mobile communications iden : integrated digital enhanced network d - amps : digital advanced mobile phone system based on tdma cdmaone : code division multiple access defined by is - 95 pdc : personal digital cellular tdma : time division multiple access 2. 5g : a set of transition technologies between 2g and 3g wireless technologies. in addition to voice, it involves digital communication technologies that support e - mail and simple web browsing. gprs : general packet radio service widen : wideband integrated dispatch enhanced network 2. 75g : refers to a technology that, although it does not meet 3g requirements, plays a role in 3g in the market. cdma2000 1xrtt : cdma - 2000 is a tia standard ( is - 2000 ) evolved from cdmaone. compared with 3g, cdma2000 supporting 1xrtt has lower requirements. edge : enhanced data rates for gsm evolution 3g : representing the third generation of wireless communication technology, it supports broadband voice, data, and multimedia communication technologies in wireless networks. w - cdma : wideband code division multiple access umts : universal mobile | https://en.wikipedia.org/wiki/Mobile_technology |
the goal of artificial intelligence based systems is to take decisions that have an effect in their environment and impact society. this points out to the necessity of mechanism that regulate the impact of this type of system in society. for this reason, it is priority to create the rules and specialized organizations that can oversight the following of such rules, particularly that human rights precepts at local and international level. this work proposes the creation, at the universities, of ethical committees or commissions specialized on artificial intelligence that would be in charge of define the principles and will guarantee the following of good practices in the field artificial intelligence. | arxiv:2002.05673 |
let $ g $ be a finite group, let $ n $ be a normal subgroup of $ g $ and let $ \ theta $ be an irreducible character of $ n $. we count the real irreducible characters of $ g $ lying over $ \ theta $ | arxiv:2301.01177 |
the momentum conservation law is applied to analyse the dynamics of pulsejet engine in vertical motion in a uniform gravitational field in the absence of friction. the model predicts existence of a terminal speed given frequency of the short pulses. the conditions that the engine does not return to the starting position are identified. the number of short periodic pulses after which the engine returns to the starting position is found to be independent of the exhaust velocity and gravitational field intensity for certain frequency of the pulses. the pulsejet engine and turbojet engine aircraft models of dynamics are compared. also the octopus dynamics is modelled. the paper is addressed to intermediate undergraduate students of classical mechanics and aerospace engineering. | arxiv:1702.00814 |
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