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multi - fiber spectroscopy has been obtained for 335 galaxies in the field of the double cluster a3128 / a3125, using the 2df multi - fiber positioner on the aat. a total of 532 objects in the double cluster now have known redshifts. we have also obtained a 20 ks chandra acis - i image of a3128 and radio imaging with the most and the atca. the spatial - kinematic distribution of redshifts in the field of a3128 / a3125, when combined with the chandra image of a3128, reveals a variety of substructures present in the galaxy distribution and in the hot icm. the most striking large - scale feature in the galaxy distribution is an underpopulated redshift zone ~ 4000 km / s on either side of the cluster velocity at ~ 17500 km / s. we attribute this depletion zone to the effect of the extensive horologium - reticulum supercluster ( hrs ), within which a3128 / a3125 is embedded. in addition, numerous smaller groups of galaxies are identified, particularly in the underpopulated region within + - 4000 km / s of the cluster redshift. due to the large gravitational influence of the hrs, these groups arrive at a3128 with a very high ( hypersonic ) infall velocity. two of these groups appear as elongated filaments in position - velocity diagrams, indicating that they are tidally distended groups which have been disrupted after a close passage through a3128. we have identified a primary ne - sw merger axis connecting a3128 with a3125, along which the filaments are also oriented. in addition, the chandra image reveals that the x - ray emission is split into two components, each with very small core radii, that are separated by ~ 1 mpc along the ne - sw axis. we propose that the complex x - ray morphology is likely the result of the hypersonic infall of a relatively small group into a3128. the group produces a major disruption in the icm due to its high infall velocity. | arxiv:astro-ph/0112346 |
we describe the role of gev gamma - ray observations with glast - lat ( gamma - ray large area space telescope - large area telescope ) in identifying interaction sites of cosmic - ray proton ( or hadrons ) with interstellar medium ( ism ). we expect to detect gamma rays from neutral pion decays in high - density ism regions in the galaxy, large magellanic cloud, and other satellite galaxies. these gamma - ray sources have been detected already with egret ( energetic gamma ray experiment telescope ) as extended sources ( eg. lmc and orion clouds ) and glast - lat will detect many more with a higher spatial resolution and in a wider spectral range. we have developed a novel image restoration technique based on the richardson - lucy algorithm optimized for glast - lat observation of extended sources. our algorithm calculates psf ( point spread function ) for each event. this step is very important for glast - lat and egret image analysis since psf varies more than one order of magnitude from one gamma ray to another depending on its energy as well as its impact point and angle in the instrument. the glast - lat and egret image analysis has to cope with poisson fluctuation due to low number of detected photons for most sources. our technique incorporates wavelet filtering to minimize effects due to the fluctuation. preliminary studies on some egret sources are presented, which shows potential of this novel image restoration technique for the identification and characterisation of extended gamma - ray sources. | arxiv:0705.1524 |
uct has recently emerged as an exciting new adversarial reasoning technique based on cleverly balancing exploration and exploitation in a monte - carlo sampling setting. it has been particularly successful in the game of go but the reasons for its success are not well understood and attempts to replicate its success in other domains such as chess have failed. we provide an in - depth analysis of the potential of uct in domain - independent settings, in cases where heuristic values are available, and the effect of enhancing random playouts to more informed playouts between two weak minimax players. to provide further insights, we develop synthetic game tree instances and discuss interesting properties of uct, both empirically and analytically. | arxiv:1203.4011 |
peculiarities of transport properties of three - and two - dimensional half - metallic ferromagnets are investigated, which are connected with the absence of spin - flip scattering processes. the temperature and magnetic field dependences of resistivity in various regimes are calculated. the resistivity is proportional to t ^ { 9 / 2 } for t < t * and to t ^ { 7 / 2 } for t > t *, t * being the crossover temperature for longitudinal scattering processes. the latter scale plays also an important role in magnetoresistance. the contribution of non - quasiparticle ( incoherent ) states to the transport properties is discussed. it is shown that they can dominate in the temperature dependence of the impurity - induced resistivity and in the tunnel junction conductivity. | arxiv:cond-mat/0204265 |
we consider the stokes parameters ' frequency spectral distortions arising due to compton scattering of the anisotropic cosmic microwave background ( cmb ) radiation, the sunyaev - zel ' dovich effect ( sz ), towards clusters of galaxies. we single out a very special type of such distortions and find simple analytical formulas for them. we show that this kind of distortion has a very distinctive spectral shape and can be separated from other kinds of contaminants. we demonstrate that this effect gives us an opportunity for an independent estimation of the low - multipole angular cmb anisotropies, such as the dipole, the quadrupole, and the octupole. we also show that, using distorted signals from nearby and distant clusters, one can distinguish between the sachs - wolfe and the integrated sachs - wolfe effects. the detection of such distortions can be feasible with high - angular resolution and high - sensitivity space missions, such as the upcoming millimetron space observatory experiment. | arxiv:2006.15571 |
the adoption of " human - in - the - loop " paradigms in computer vision and machine learning is leading to various applications where the actual data acquisition ( e. g., human supervision ) and the underlying inference algorithms are closely interwined. while classical work in active learning provides effective solutions when the learning module involves classification and regression tasks, many practical issues such as partially observed measurements, financial constraints and even additional distributional or structural aspects of the data typically fall outside the scope of this treatment. for instance, with sequential acquisition of partial measurements of data that manifest as a matrix ( or tensor ), novel strategies for completion ( or collaborative filtering ) of the remaining entries have only been studied recently. motivated by vision problems where we seek to annotate a large dataset of images via a crowdsourced platform or alternatively, complement results from a state - of - the - art object detector using human feedback, we study the " completion " problem defined on graphs, where requests for additional measurements must be made sequentially. we design the optimization model in the fourier domain of the graph describing how ideas based on adaptive submodularity provide algorithms that work well in practice. on a large set of images collected from imgur, we see promising results on images that are otherwise difficult to categorize. we also show applications to an experimental design problem in neuroimaging. | arxiv:2008.05060 |
we establish a framework for the existence and uniqueness of solutions to stochastic nonlinear ( possibly multi - valued ) diffusion equations driven by multiplicative noise, with the drift operator $ l $ being the generator of a transient dirichlet form on a finite measure space $ ( e, \ mathcal { b }, \ mu ) $ and the initial value in $ \ mathcal { f } _ e ^ * $, which is the dual space of an extended transient dirichlet space. $ l $ and $ \ mathcal { f } _ e ^ * $ replace the laplace operator $ \ delta $ and $ h ^ { - 1 } $, respectively, in the classical case. this framework includes stochastic fast diffusion equations, stochastic fractional fast diffusion equations, the zhang model, and apply to cases with $ e $ being a manifold, a fractal or a graph. in addition, our results apply to operators $ - f ( - l ) $, where $ f $ is a bernstein function, e. g. $ f ( \ lambda ) = \ lambda ^ \ alpha $ or $ f ( \ lambda ) = ( \ lambda + 1 ) ^ \ alpha - 1 $, $ 0 < \ alpha < 1 $. | arxiv:2402.01479 |
charge unbalance is one of the key issues for series - connected lithium - ion cells. within this context, model - based optimization strategies have proven to be the most effective. in the present paper, an ad - hoc electrochemical model, tailored to control purposes, is firstly presented. relying on this latter, a general nonlinear mpc for balancing - aware optimal charging is then proposed. in view of the possibility of a practical implementation, the concepts are subsequently specialized for an easily implementable power supply scheme. finally, the nonlinear mpc approach is validated on commercial cells using a detailed battery simulator, with sound evidence of its effectiveness. | arxiv:1902.02122 |
context. sn 2023ixf was discovered in galaxy m101 in may 2023. its proximity made it an extremely valuable opportunity for the scientific community to study the characteristics of the sn and its progenitor. a point source detected on archival images and hydrodynamical modelling of the bolometric light curve has been used to constrain the former star ' s properties. there is a significant variation in the published results regarding the initial mass of the progenitor. nebular spectroscopy provides an independent tool to enhance our understanding of the supernova and its progenitor. aims. we determine the sn progenitor mass by studying the first published nebular spectrum taken 259 days after the explosion. methods. we analyze the nebular spectrum taken with gmos at the gemini north telescope. typical emission lines are identified, such as [ o i ], h { \ alpha }, [ ca ii ], among others. some species ' line profiles show broad and narrow components, indicating two ejecta velocities and an asymmetric ejecta. we infer the progenitor mass of sn 2023ixf by comparing with synthetic spectra and by measuring the forbidden oxygen doublet flux. results. based on the flux ratio and the direct comparison with spectra models, the progenitor star of sn 2023ixf had a m _ { zams } between 12 and 15 m { _ \ odot }. in comparison with this, we find the use of the [ o i ] doublet flux to be less constraining of the progenitor mass. our results agree with those from hydrodynamical modelling of the early light curve and pre - explosion image estimates pointing to a relatively low - mass progenitor. | arxiv:2406.00130 |
as a software system evolves, its architecture tends to degrade, and gradually impedes software maintenance and evolution activities and negatively impacts the quality attributes of the system. the main root cause behind architecture erosion phenomenon derives from violation symptoms ( such as violations of architecture pattern ). previous studies focus on detecting violations in software systems using architecture conformance checking approaches. however, code review comments are also rich sources that may contain extensive discussions regarding architecture violations. in this work, we investigated the characteristics of architecture violation symptoms in code review comments from the developers ' perspective. we employed a set of keywords related to violation symptoms to collect 606 ( out of 21, 583 ) code review comments from four popular oss projects in the openstack and qt communities. we manually analyzed the collected 606 review comments to provide the categories and linguistic patterns of violation symptoms, as well as the reactions how developers addressed them. our findings show that : ( 1 ) 10 categories of violation symptoms are discussed by developers during the code review process ; ( 2 ) the frequently - used terms of expressing violation symptoms are " inconsistent " and " violate ", and the most frequently - used linguistic pattern is problem discovery ; ( 3 ) refactoring and removing code are the major measures ( 90 % ) to tackle violation symptoms, while a few violation symptoms were ignored by developers. our findings suggest that the investigation of violation symptoms can help researchers better understand the characteristics of architecture erosion and facilitate the development and maintenance activities, and developers should explicitly manage violation symptoms, not only for addressing the existing architecture violations but also preventing future violations. | arxiv:2212.12168 |
in this article we study combinatorial degenerations of minimal surfaces of kodaira dimension 0 over local fields, and in particular show that the ` type ' of the degeneration can be read off from the monodromy operator acting on a suitable cohomology group. this can be viewed as an arithmetic analogue of results of persson and kulikov on degenerations of complex surfaces, and extends various particular cases studied by matsumoto, liedtke / matsumoto and hern \ ' andez - mada. we also study ` maximally unipotent ' degenerations of calabi - - yau threefolds, following koll \ ' ar / xu, showing in this case that the dual intersection graph is a 3 - sphere. | arxiv:1602.04063 |
we measure the $ d ^ 0 - { \ bar { d } } ^ 0 $ mixing parameters using a time - dependent amplitude analysis of the decay $ d ^ 0 \ to \ pi ^ + \ pi ^ - \ pi ^ 0 $. the data were recorded with the babar detector at center - of - mass energies at and near the $ \ upsilon ( 4s ) $ resonance, and correspond to an integrated luminosity of approximately 468. 1 $ { \ rm fb } ^ { - 1 } $. the neutral $ d $ meson candidates are selected from $ d ^ { * } ( 2010 ) ^ + \ to d ^ 0 \ pi _ s ^ + $ decays where the flavor at the production is identified by the charge of the low momentum pion, $ \ pi _ s ^ + $. the measured mixing parameters are $ x = ( 1. 5 \ pm1. 2 \ pm0. 6 ) \ % $ and $ y = ( 0. 2 \ pm0. 9 \ pm0. 5 ) \ % $, where the quoted uncertainties are statistical and systematic, respectively. | arxiv:1604.00857 |
in recent years, multi - armed bandit ( mab ) framework has attracted a lot of attention in various applications, from recommender systems and information retrieval to healthcare and finance, due to its stellar performance combined with certain attractive properties, such as learning from less feedback. the multi - armed bandit field is currently flourishing, as novel problem settings and algorithms motivated by various practical applications are being introduced, building on top of the classical bandit problem. this article aims to provide a comprehensive review of top recent developments in multiple real - life applications of the multi - armed bandit. specifically, we introduce a taxonomy of common mab - based applications and summarize state - of - art for each of those domains. furthermore, we identify important current trends and provide new perspectives pertaining to the future of this exciting and fast - growing field. | arxiv:1904.10040 |
many - particle qed is applied to kinetic theory of radiative processes in many - component plasmas with relativistic electrons and nonrelativistic heavy particles. within the framework of nonequilibrium green ' s function technique, transport and mass - shell equations for fluctuations of the electromagnetic field are obtained. we show that the transverse field correlation functions can be decomposed into sharply peaked ( non - lorentzian ) parts that describe resonant ( propagating ) photons and off - shell parts corresponding to virtual photons in plasmas. analogous decomposi - tions are found for the longitudinal field correlation functions and the correlation functions of relativistic electrons. as a novel result a kinetic equation for the reso - nant photons with a finite spectral width is derived. the off - shell parts of the particle and field correlation functions are shown to be essential to calculate the local ra - diating power in relativistic plasmas and recover the results of vacuum qed. the influence of plasma effects and collisional broadening of the relativistic quasiparticle spectral function on radiative processes is discussed. | arxiv:0902.0537 |
for an infinite dimensional lie group $ g $ modelled on a locally convex lie algebra $ \ mathfrak { g } $, we prove that every smooth projective unitary representation of $ g $ corresponds to a smooth linear unitary representation of a lie group extension $ g ^ { \ sharp } $ of $ g $. ( the main point is the smooth structure on $ g ^ { \ sharp } $. ) for infinite dimensional lie groups $ g $ which are 1 - connected, regular, and modelled on a barrelled lie algebra $ \ mathfrak { g } $, we characterize the unitary $ \ mathfrak { g } $ - representations which integrate to $ g $. combining these results, we give a precise formulation of the correspondence between smooth projective unitary representations of $ g $, smooth linear unitary representations of $ g ^ { \ sharp } $, and the appropriate unitary representations of its lie algebra $ \ mathfrak { g } ^ { \ sharp } $. | arxiv:1501.00939 |
we study the spectral energy distribution ( sed ) and the power spectrum of galactic cirrus emission observed in the 14 deg ^ 2 science demonstration phase field of the herschel - atlas using herschel and iras data from 100 to 500 um. we compare the spire 250, 350 and 500um maps with iras 100um emission, binned in 6 ' pixels. we assume a modified black - body sed with dust emissivity parameter beta ( f ~ lambda ^ ( - beta ) ) and a single dust temperature t _ d, and find that the dust temperature and emissivity index varies over the science demonstration field as 10 < t _ rm < 25 k and 1 < beta < 4. the latter values are somewhat higher than the range of beta often quoted in the literature ( 1 < beta < 2 ). we estimate the mean values of these parameters to be t _ d = 19. 0 + / - 2. 4 k and beta = 1. 4 + / - 0. 4. in regions of bright cirrus emission, we find that the dust has similar temperatures with t _ d = 18. 0 + / - 2. 5 k, and similar values of beta, ranging from 1. 4 + - 0. 5 to 1. 9 + / - 0. 5. we show that t _ d and beta associated with diffuse cirrus emission are anti - correlated and can be described by the relationship : beta ( t _ d ) = nt _ d ^ alpha with [ n = 116 + / - 38, alpha = - 1. 4 + / 1 0. 1 ]. the strong correlation found in this analysis is not just limited to high density clumps of cirrus emission as seen in previous studies, but is also seen in diffuse cirrus in low density regions. to provide an independent measure of $ t _ { \ rm d } $ and $ \ beta $, we obtain the angular power spectrum of the cirrus emission in the { \ it iras } and spire maps, which is consistent with a power spectrum of the form p ( k ) = p _ 0 ( k / k _ 0 ) ^ gamma where gamma = \ ^ a h r2. 6 + / - m 0. 2 for scales of 50 - 200 ' in the spire maps. the cirrus rms fluctuation amplitude at angular scales of 100 ' is consistent with a modified blackbody sed with t _ d = 20. 1 + / - 0. 9 k and | arxiv:1011.0725 |
we present the spectroscopic characterization of the unusual high - amplitude very low mass pre - main - sequence periodic variable chs7797. this study is based on optical medium - resolution ( r = 2200 ) spectroscopy in the 6450 - 8600 a range, carried out with gmos - gemini - s in march 2011. observations of chs7797 have been carried out at two distinct phases of the 17. 8d period, namely at maximum and four days before maximum. four different spectral indices were used for the spectral classification at these two phases, all of them well - suited for spectral classification of young and obscured late m dwarfs. in addition, the gravity - sensitive nai ( 8183 / 8195 a ) and ki ( 7665 / 7699 a ) doublet lines were used to confirm the young age of chs7797. from the spectrum obtained at maximum light we derived a spectral type ( spt ) of m6. 05, while for the spectrum taken four days before maximum the derived spt is m5. 75. the derived spts confirm that chs7797 has a mass in the stellar - substellar boundary mass range. in addition, the small differences in the derived spts at the two observed phases may provide indirect hints that chs7797 is a binary system of similar mass components surrounded by a tilted circumbinary disk, a system similar to kh15d. | arxiv:1301.5913 |
this paper presents an uncertainty compensation - based robust adaptive model predictive control ( mpc ) framework for linear systems with both matched and unmatched nonlinear uncertainties subject to both state and input constraints. in particular, the proposed control framework leverages an l1 adaptive controller ( l1ac ) to compensate for the matched uncertainties and to provide guaranteed uniform bounds on the error between the states and control inputs of the actual system and those of a nominal i. e., uncertainty - free, system. the performance bounds provided by the l1ac are then used to tighten the state and control constraints of the actual system, and a model predictive controller is designed for the nominal system with the tightened constraints. the proposed control framework, which we denote as uncertainty compensation - based mpc ( uc - mpc ), guarantees constraint satisfaction and achieves improved performance compared with existing methods. simulation results on a flight control example demonstrate the benefits of the proposed framework. | arxiv:2309.13743 |
the violation of the cauchy - schwarz and bell inequalities ranks among the major evidences of the genuinely quantum nature of an emitter. we show that by dispensing from the usual approximation of mode correlations and studying directly correlations between the physical reality - the photons - these violations can be optimized. this is achieved by extending the concept of photon correlations to all frequencies in all the possible windows of detections, with no prejudice to the supposed origin of the photons. we identify the regions of quantum emission as rooted in collective de - excitation involving virtual states instead of, as previously assumed, cascaded transitions between real states. | arxiv:1403.6182 |
a signed magic rectangle $ smr ( m, n ; r, s ) $ is an $ m \ times n $ array with entries from $ x $, where $ x = \ { 0, \ pm1, \ pm2, \ ldots, $ $ \ pm ( ms - 1 ) / 2 \ } $ if $ mr $ is odd and $ x = \ { \ pm1, \ pm2, \ ldots, \ pm mr / 2 \ } $ if $ mr $ is even, such that precisely $ r $ cells in every row and $ s $ cells in every column are filled, every integer from set $ x $ appears exactly once in the array and the sum of each row and of each column is zero. in this paper we prove that a signed magic rectangle $ smr ( m, n ; r, 2 ) $ exists if and only if either $ m = 2 $ and $ n = r \ equiv 0, 3 \ pmod 4 $ or $ m, r \ geq 3 $ and $ mr = 2n $. | arxiv:1901.05502 |
we study the electronic band structure of three - dimensional abc - stacked ( rhombohedral ) graphdiyne, which is a new planar carbon allotrope recently fabricated. using the first - principles calculation, we show that the system is a nodal - line semimetal, in which the conduction band and valence band cross at a closed ring in the momentum space. we derive the minimum tight - binding model and the low - energy effective hamiltonian in a $ 4 \ times 4 $ matrix form. the nodal line is protected by a non - trivial winding number, and it ensures the existence of the topological surface state in a finite - thickness slab. the fermi surface of the doped system exhibits a peculiar, self - intersecting hourglass structure, which is quite different from the torus or pipe shape in the previously proposed nodal semimetals. despite its simple configuration, three - dimensional graphdiyne offers unique electronic properties distinct from any other carbon allotropes. | arxiv:1804.01838 |
high resolution computed tomography ( hrct ) is the most important imaging modality for interstitial lung diseases, where the radiologists are interested in identifying certain patterns, and their volumetric and regional distribution. the use of machine learning can assist the radiologists with both these tasks by performing semantic segmentation. in this paper, we propose an interactive annotation - tool for semantic segmentation that assists the radiologist in labeling ct scans. the annotation tool is evaluated by six radiologists and radiology residents classifying healthy lung and reticular pattern i hrct images. the usability of the system is evaluated with a system usability score ( sus ) and interaction information from the readers that used the tool for annotating the ct volumes. it was discovered that the experienced usability and how the users interactied with the system differed between the users. a higher sus - score was given by users that prioritized learning speed over model accuracy and spent less time with manual labeling and instead utilized the suggestions provided by the gui. an analysis of the annotation variations between the readers show substantial agreement ( cohen ' s kappa = 0. 69 ) for classification of healthy and affected lung parenchyma in pulmonary fibrosis. the inter - reader variation is a challenge for the definition of ground truth. | arxiv:1904.11701 |
this work discusses a novel framework for simultaneous synthesis of optimal watermarking signal and robust controllers in cyber - physical systems to minimize the loss in performance due to added watermarking signal and to maximize the detection rate of the attack. a general dynamic controller is designed to improve system performance with respect to the $ \ mathcal h _ 2 $ norm, while a watermarking signal is added to improve security performance concerning the detection rate of replay attacks. the attack model considered in the paper is a replay attack, a natural attack mode when the dynamics of the system is unknown to the attacker. the paper first generalizes the existing result on the detection rate of $ \ chi ^ 2 $ detector from a static - lqr controller to a general dynamic controller. the design improvements on both robustness and security fronts are obtained by iteratively solving the convex subsets of the formulated non - convex problem in terms of the controller and watermarking signal. a semi - definite programming optimization is formulated using linear matrix inequality ( lmi ) results to solve the larger system - level design optimization problem. we highlight the effectiveness of our method over a simplified three - tank chemical system. | arxiv:2209.06267 |
we continue our study of maps transforming high - dimensional complicated objects into squares of stationary sets. previously, we proved that many such transformations exist in zfc, and here we address the consistency of the strongest conceivable transformations. along the way, we obtain new results on shelah ' s coloring principle $ pr _ 1 $. for $ \ kappa $ inaccessible, we prove the consistency of $ pr _ 1 ( \ kappa, \ kappa, \ kappa, \ kappa ) $. for successors of regulars, we obtain a full lifting of galvin ' s 1980 theorem. in contrast, the full lifting of galvin ' s theorem to successors of singulars is shown to be inconsistent. | arxiv:2104.15031 |
we prove that in the game of life, if the thickness - four zero - padding of a rectangular pattern is not an orphan, then the corresponding finite - support configuration is not a garden of eden, and that the preimage of every finite - support configuration has dense semilinear configurations. in particular finite - support gardens of eden are in co - np. | arxiv:1912.00692 |
the problem of $ n $ particles interacting through pairwise central forces is notoriously intractable for $ n \ geq3 $. some quite remarkable specific cases have been solved in one dimension, whereas higher - dimensional exactly solved systems involve velocity - dependent or many - body forces. here we show that the guiding center approximation - - - valid for charges moving in two dimensions in a strong constant magnetic field - - - simplifies the three - body problem for an arbitrary interparticle interaction invariant under rotations and translations and makes it solvable by quadratures. this includes a broad variety of special cases, such as that of three particles interacting through arbitrary pairwise central potentials. a spinorial representation for the system is introduced, which allows a visualization of its phase space as the corresponding bloch sphere as well as the identification of a berry - hannay rotational anholonomy. finally, a brief discussion of the quantization of the problem is presented. | arxiv:1410.6221 |
transient microstructure in the diffuse interstellar medium has been observed towards galactic and extragalactic sources for decades, usually in lines of atoms and ions, and, more recently, in molecular lines. evidently, there is a molecular component to the transient microstructure. in this paper we explore the chemistry that may arise in such microstructure. we use a pdr code to model the conditions of relatively high density, low temperature, very low visual extinction and very short elapsed time that are appropriate for these objects. we find that there is a well defined region of parameter space where detectable abundances of molecular species might be found. the best matching models are those where the interstellar microstructure is young ( < 100 yr ), small ( ~ 100 au ), and dense ( > 10 ^ 4 cm ^ - 3 ). | arxiv:astro-ph/0412291 |
we establish a map between ads $ _ 3 \ times $ s $ ^ 2 $ and ads $ _ 7 $ solutions to massive iia supergravity that allows one to interpret the former as holographic duals to d2 - d4 defects inside 6d ( 1, 0 ) cfts. this relation singles out in a particular manner the ads $ _ 3 \ times $ s $ ^ 2 $ solution constructed from ads $ _ 3 \ times $ s $ ^ 3 \ times $ cy $ _ 2 $ through non - abelian t - duality, with respect to a freely acting su ( 2 ). we find explicit global completions to this solution and provide well - defined ( 0, 4 ) 2d dual cfts associated to them. these completions consist of linear quivers with colour groups coming from d2 and d6 branes and flavour groups coming from d8 and d4 branes. finally, we discuss the relation with flows interpolating between ads $ _ 3 \ times $ s $ ^ 2 \ times $ t $ ^ 4 $ geometries and ads $ _ 7 $ solutions found in the literature. | arxiv:1909.11669 |
biological engineering or bioengineering is the application of principles of biology and the tools of engineering to create usable, tangible, economically viable products. biological engineering employs knowledge and expertise from a number of pure and applied sciences, such as mass and heat transfer, kinetics, biocatalysts, biomechanics, bioinformatics, separation and purification processes, bioreactor design, surface science, fluid mechanics, thermodynamics, and polymer science. it is used in the design of medical devices, diagnostic equipment, biocompatible materials, renewable energy, ecological engineering, agricultural engineering, process engineering and catalysis, and other areas that improve the living standards of societies. examples of bioengineering research include bacteria engineered to produce chemicals, new medical imaging technology, portable and rapid disease diagnostic devices, prosthetics, biopharmaceuticals, and tissue - engineered organs. bioengineering overlaps substantially with biotechnology and the biomedical sciences in a way analogous to how various other forms of engineering and technology relate to various other sciences ( such as aerospace engineering and other space technology to kinetics and astrophysics ). generally, biological engineers attempt to mimic biological systems to create products or modify and control biological systems. working with doctors, clinicians, and researchers, bioengineers use traditional engineering principles and techniques to address biological processes, including ways to replace, augment, sustain, or predict chemical and mechanical processes. = = history = = biological engineering is a science - based discipline founded upon the biological sciences in the same way that chemical engineering, electrical engineering, and mechanical engineering can be based upon chemistry, electricity and magnetism, and classical mechanics, respectively. before wwii, biological engineering had begun being recognized as a branch of engineering and was a new concept to people. post - wwii, it grew more rapidly, and the term " bioengineering " was coined by british scientist and broadcaster heinz wolff in 1954 at the national institute for medical research. wolff graduated that year and became the division of biological engineering director at oxford. this was the first time bioengineering was recognized as its own branch at a university. the early focus of this discipline was electrical engineering due to the work with medical devices and machinery during this time. when engineers and life scientists started working together, they recognized that the engineers did not know enough about the actual biology behind their work. to resolve this problem, engineers who wanted to get into biological engineering devoted more time to studying the processes of biology, psychology, and medicine | https://en.wikipedia.org/wiki/Biological_engineering |
the selfconsistent approach to the 2d ising model with quenched random bonds is extended to the full lattice theory of four real fermions. the additional degrees of freedom, neglected in the renormalization - group theory, lead to a new phase between the ferromagnetic and the paramagnetic phase. the disorder averaged spin - spin correlation function decays exponentially with distance. the corresponding correlation length is $ 1 / \ eta ^ 2 $, where $ \ eta $ denotes the order parameter of the new phase introduced by ziegler. | arxiv:cond-mat/9310045 |
this study introduces an algorithm that generates undirected graphs with three main characteristics of real - world networks : scale - freeness, short distances between nodes ( small - world phenomenon ), and large clustering coefficients. the main idea is to perform random walks across the network and, at each iteration, add special edges with a decreasing probability to link more distant nodes, following a specific probability distribution. a key advantage of our algorithm is its simplicity and flexibility in creating networks with different characteristics without using global information about network topology. we show how the parameters can be adjusted to generate networks with specific average distances and clustering coefficients, maintaining a long - tailed degree distribution. the implementation of our algorithm is publicly available on a github repository. | arxiv:2502.18579 |
we report a systematic quantitative evaluation of parametric amplification gain of magnetization dynamics in ytirrium iron garnet ( $ \ mathrm { y } _ 3 \ mathrm { fe } _ 5 \ mathrm { o } _ { 12 } $ ) thin disk via a. c. spin pumping and inverse spin hall effect. we demonstrate its signature phase - dependence where amplification and attenuation occur every $ \ frac { \ pi } { 2 } $ phase shift of the input signal. the results also show the pump - power dependence of the gain that is explained well by our theoretical model. finally, the optimal conditions for the amplification is investigated by measuring the magnetic field dependence, where we find the highest gain of 11. 4 db. | arxiv:2309.00259 |
starting with an isolated vertex, here we construct a threshold hypergraph by repeatedly adding an isolated vertex or a $ k $ - dominating vertex set. we represent a threshold hypergraph by a string of non - negative integers and find the laplacian spectrum of threshold hypergraphs from their string representation. we also compute the complete laplacian spectrum of certain threshold hypergraphs from the ferrer ' s diagram of their degree sequences. we show that the laplacian spectra of threshold hypergraphs are $ r $ - integral, i. e., integral multiple of $ r $, for some $ r \ in \ mathbb { q } $. we also construct another class of hypergraphs whose laplacian spectra are $ r $ - integral. | arxiv:2207.02528 |
performance. it is a subset of the larger field of human factors and ergonomics. applied psychology - the use of psychological principles to overcome problems in other domains. it has been argued that engineering psychology is separate from applied ( cognitive ) psychology because advances in cognitive psychology have infrequently informed engineering psychology research. surprisingly, work in engineering psychology often seems to inform developments in cognitive psychology. for example, engineering psychology research has enabled cognitive psychologists to explain why guis seem easier to use than character - based computer interfaces ( such as dos ). = = = engineering psychology, ergonomics and human factors = = = although the comparability of these terms and many others have been a topic of debate, the differences of these fields can be seen in the applications of the respective fields. engineering psychology is concerned with the adaptation of the equipment and environment to people, based upon their psychological capacities and limitations with the objective of improving overall system performance, involving human and machine elements engineering psychologists strive to match equipment requirements with the capabilities of human operators by changing the design of the equipment. an example of this matching was the redesign of the mailbags used by letter carriers. engineering psychologists discovered that mailbag with a waist - support strap, and a double bag that requires the use of both shoulders, reduces muscle fatigue. another example involves the cumulative trauma disorders grocery checkout workers suffered as the result of repetitive wrist movements using electronic scanners. engineering psychologists found that the optimal checkout station design would allow for workers to easily use either hand to distribute the workload between both wrists. the field of ergonomics is based on scientific studies of ordinary people in work situations and is applied to the design of processes and machines, to the layout of work places, to methods of work, and to the control of the physical environment, in order to achieve greater efficiency of both men and machines an example of an ergonomics study is the evaluation of the effects of screwdriver handle shape, surface material and workpiece orientation on torque performance, finger force distribution and muscle activity in a maximum screwdriving torque task. another example of an ergonomics study is the effects of shoe traction and obstacle height on friction. similarly, many topics in ergonomics deal with the actual science of matching man to equipment and encompasses narrower fields such as engineering psychology. at one point in time, the term human factors was used in place of ergonomics in europe. human factors involve interdisciplinary scientific research and studies to seek to realize greater recognition and understanding of the worker ' s characteristics, needs | https://en.wikipedia.org/wiki/Engineering_psychology |
classical and quantum perturbations can be described in terms of marginal distribution functions in the framework of tomographic cosmology. in particular, the so called radon transformation and the mode - parametric quantum oscillator description can give rise to links between quantum and classical regimes. the approach results a natural scheme to discuss the transition from the quantum to the classical perturbations and then it could be a workable scheme to connect primordial fluctuations with the today observed large scale structure. | arxiv:0905.1244 |
in this paper, by the method of moving planes, we prove the symmetry result which says that classical solutions of monge - ampere system in the whole plane are symmetric about some point. our system under consideration comes from the differential geometry problem. | arxiv:0908.1428 |
we prove an asymptotic implicit function theorem in the setting of gevrey asymptotics with respect to a parameter. the unique implicitly defined solution admits a gevrey asymptotic expansion and furthermore it is the borel resummation of the corresponding implicitly defined formal power series solution. the main theorem can therefore be rephrased as an implicit function theorem for borel summable power series. as an application, we give a diagonal or jordan decomposition for holomorphic matrices in gevrey asymptotic families. | arxiv:2112.08792 |
we consider a universe filled with perfect fluid with the constant equation of state parameter $ \ omega $. in the theory of scalar perturbations, we study the effect of peculiar velocities on the gravitational potential. for radiation with $ \ omega = 1 / 3 $, we obtain the expression for the gravitational potential in the integral form. numerical calculation clearly demonstrates the modulation of the gravitational potential by acoustic oscillations due to the presence of peculiar velocities. we also show that peculiar velocities affect the gravitational potential in the case of the frustrated network of cosmic strings with $ \ omega = - 1 / 3 $. | arxiv:2005.06237 |
spiking neural networks ( snns ), inspired by the spiking computation paradigm of the biological neural systems, have exhibited superior energy efficiency in 2d classification tasks over traditional artificial neural networks ( anns ). however, the regression potential of snns has not been well explored, especially in 3d point cloud processing. in this paper, we propose noise - injected spiking graph convolutional networks to leverage the full regression potential of snns in 3d point cloud denoising. specifically, we first emulate the noise - injected neuronal dynamics to build noise - injected spiking neurons. on this basis, we design noise - injected spiking graph convolution for promoting disturbance - aware spiking representation learning on 3d points. starting from the spiking graph convolution, we build two snn - based denoising networks. one is a purely spiking graph convolutional network, which achieves low accuracy loss compared with some ann - based alternatives, while resulting in significantly reduced energy consumption on two benchmark datasets, pu - net and pc - net. the other is a hybrid architecture that combines ann - based learning with a high performance - efficiency trade - off in just a few time steps. our work lights up snn ' s potential for 3d point cloud denoising, injecting new perspectives of exploring the deployment on neuromorphic chips while paving the way for developing energy - efficient 3d data acquisition devices. | arxiv:2502.19660 |
natural metrics ( sasaki metric, cheeger - gromoll metric, kaluza - klein metrics etc.. ) on the tangent bundle of a riemannian manifold is a central topic in riemannian geometry. generalized cheeger - gromoll metrics is a family of natural metrics $ h _ { p, q } $ depending on two parameters with $ p \ in \ mathbb { r } $ and $ q \ geq0 $. this family has been introduced recently and possesses interesting geometric properties. if $ p = q = 0 $ we recover the sasaki metric and when $ p = q = 1 $ we recover the classical cheeger - gromoll metric. a transitive euclidean lie algebroid is a transitive lie algebroid with an euclidean product on its total space. in this paper, we show that natural metrics can be built in a natural way on the total space of transitive euclidean lie algebroids. then we study the properties of generalized cheeger - gromoll metrics on this new context. we show a rigidity result of this metrics which generalizes so far all rigidity results known in the case of the tangent bundle. we show also that considering natural metrics on the total space of transitive euclidean lie algebroids opens new interesting horizons. for instance, atiyah lie algebroids constitute an important class of transitive lie algebroids and we will show that natural metrics on the total space of atiyah euclidean lie algebroids have interesting properties. in particular, if $ m $ is a riemannian manifold of dimension $ n $, then the atiyah lie algebroid associated to the $ \ mathrm { o } ( n ) $ - principal bundle of orthonormal frames over $ m $ possesses a family depending on a parameter $ k > 0 $ of transitive euclidean lie algebroids structures say $ ao ( m, k ) $. when $ m $ is a space form of constant curvature $ c $, we show that there exists two constants $ c _ n < 0 $ and $ k ( n, c ) > 0 $ such that $ ( ao ( m, k ), h _ { 1, 1 } ) $ is a riemannian manifold with positive scalar curvature if and only if $ c > c _ n $ and $ 0 < k \ leq k ( n, c ) $ | arxiv:1808.01254 |
our goal is to recover time - delayed latent causal variables and identify their relations from measured temporal data. estimating causally - related latent variables from observations is particularly challenging as the latent variables are not uniquely recoverable in the most general case. in this work, we consider both a nonparametric, nonstationary setting and a parametric setting for the latent processes and propose two provable conditions under which temporally causal latent processes can be identified from their nonlinear mixtures. we propose leap, a theoretically - grounded framework that extends variational autoencoders ( vaes ) by enforcing our conditions through proper constraints in causal process prior. experimental results on various datasets demonstrate that temporally causal latent processes are reliably identified from observed variables under different dependency structures and that our approach considerably outperforms baselines that do not properly leverage history or nonstationarity information. this demonstrates that using temporal information to learn latent processes from their invertible nonlinear mixtures in an unsupervised manner, for which we believe our work is one of the first, seems promising even without sparsity or minimality assumptions. | arxiv:2110.05428 |
in 1994, s. g. matthews introduced the notion of partial metric space in order to obtain a suitable mathematical tool for program verification [ ann. new york acad. sci. 728 ( 1994 ), 183 - 197 ]. he gave an application of this new structure to parallel computing by means of a partial metric version of the celebrated banach fixed point theorem [ theoret. comput. sci. 151 ( 1995 ), 195 - 205 ]. later on, m. p. schellekens introduced the theory of complexity ( quasi - metric ) spaces as a part of the development of a topological foundation for the asymptotic complexity analysis of programs and algorithms [ elec - tronic notes in theoret. comput. sci. 1 ( 1995 ), 211 - 232 ]. the applicability of this theory to the asymptotic complexity analysis of divide and conquer algorithms was also illustrated by schellekens. in particular, he gave a new proof, based on the use of the aforenamed banach fixed point theorem, of the well - known fact that mergesort al - gorithm has optimal asymptotic average running time of computing. in this paper, motivated by the utility of partial metrics in computer science, we discuss whether the matthews fixed point theorem is a suitable tool to analyze the asymptotic complexity of algorithms in the spirit of schellekens. specifically, we show that a slight modification of the well - known baire partial metric on the set of all words over an alphabet constitutes an appropriate tool to carry out the asymptotic complexity analysis of algorithms via fixed point methods without the need for assuming the convergence condition inherent to the defini - tion of the complexity space in the shellekens framework. finally, in order to illustrate and to validate the developed theory we apply our results to analyze the asymptotic complexity of quicksort, mergesort and largesort algorithms. | arxiv:1009.6105 |
biological microswimmers often inhabit a porous or crowded environment such as soil. in order to understand how such a complex environment influences their spreading, we numerically study non - interacting active brownian particles ( abps ) in a two - dimensional random lorentz gas. close to the percolation transition in the lorentz gas, they perform the same subdiffusive motion as ballistic and diffusive particles. however, due to their persistent motion they reach their long - time dynamics faster than passive particles and also show superdiffusive motion at intermediate times. while above the critical obstacle density $ \ eta _ c $ the abps are trapped, their long - time diffusion below $ \ eta _ c $ is strongly influenced by the propulsion speed $ v _ 0 $. with increasing $ v _ 0 $, abps are stuck at the obstacles for longer times. thus, for large propulsion speed, the long - time diffusion constant decreases more strongly in a denser obstacle environment than for passive particles. this agrees with the behavior of an effective swimming velocity and persistence time, which we extract from the velocity autocorrelation function. | arxiv:1611.07892 |
we analyze a flux - limited sample of persistent and bright ( with 2 - 10 kev fluxes exceeding 1. 4e - 10 erg / s / cm2 ) low - mass x - ray binaries ( lmxbs ) in our galaxy. it is demonstrated that the majority of binary systems with x - ray luminosities below logl ( erg / sec ) ~ 37. 3 have unevolved secondary companions ( except for those with white dwarf donors ), while systems with higher x - ray luminosity predominantly harbor giant donors. mass transfer in binary systems with giants significantly shortens their life time thus steepening the x - ray luminosity function of lmxbs at high luminosity. we argue that this is the reason why the lmxb luminosity function constructed in the last years from observations of sources in our and distant galaxies demonstrates a break at logl ( erg / sec ) ~ 37. 3. | arxiv:1011.5024 |
motivated by applications to the langlands program, aubert - moussaoui - solleveld extended lusztig ' s generalized springer correspondence to disconnected reductive groups. we use stacks to give a more geometric account of their theory, in particular, formulating a truly geometric version of the ( relevant analogue of the ) bernstein - zelevinsky geometrical lemma and explaining how to compare the correspondence on the group and the lie algebra using quasi - logarithms. as an application, we study kaletha ' s rigid enhancements of l - parameters and draw the same conclusions as aubert - moussaoui - solleveld for this enhancement : there exists a cuspidal support map and its fibers are parameterized by irreducible representations of twisted group algebras. | arxiv:2308.11752 |
we survey on algebraically elliptic varieties in the sense of gromov. | arxiv:2409.04776 |
the lhc discovery potential of heavy top partners decaying into a top quark and a $ z $ boson is studied in the trilepton channel at 13 tev in the single production mode. the clean multilepton final state allows to strongly reduce the background contaminations and to reconstruct the $ t ' $ mass. we show that a simple cut - and - count analysis probes the parameter space of a simplified model as efficiently as a dedicated multivariate analysis. the trilepton signature finally turns out to be able to probe $ t ' $ masses up to $ 2. 0 $ tev, when mixing with first generation quarks is included. the reinterpretation in terms of the top - $ z $ - quark anomalous coupling is shown. | arxiv:1509.07646 |
we consider the task of low - multilinear - rank functional regression, i. e., learning a low - rank parametric representation of functions from scattered real - valued data. our first contribution is the development and analysis of an efficient gradient computation that enables gradient - based optimization procedures, including stochastic gradient descent and quasi - newton methods, for learning the parameters of a functional tensor - train ( ft ). the functional tensor - train uses the tensor - train ( tt ) representation of low - rank arrays as an ansatz for a class of low - multilinear - rank functions. the ft is represented by a set of matrix - valued functions that contain a set of univariate functions, and the regression task is to learn the parameters of these univariate functions. our second contribution demonstrates that using nonlinearly parameterized univariate functions, e. g., symmetric kernels with moving centers, within each core can outperform the standard approach of using a linear expansion of basis functions. our final contributions are new rank adaptation and group - sparsity regularization procedures to minimize overfitting. we use several benchmark problems to demonstrate at least an order of magnitude lower accuracy with gradient - based optimization methods than standard alternating least squares procedures in the low - sample number regime. we also demonstrate an order of magnitude reduction in accuracy on a test problem resulting from using nonlinear parameterizations over linear parameterizations. finally we compare regression performance with 22 other nonparametric and parametric regression methods on 10 real - world data sets. we achieve top - five accuracy for seven of the data sets and best accuracy for two of the data sets. these rankings are the best amongst parametric models and competetive with the best non - parametric methods. | arxiv:1801.00885 |
one of the highest priority physics goals for the upgraded tevatron experiments, cdf and d0, is the search for the higgs boson. we present the initial results from both experiments, based on 40 - - 90 pb $ ^ { - 1 } $ integrated luminosity, of higgs searches in several final states, including $ wh $ and $ zh $, $ h \ to ww $, and doubly - charged higgs. | arxiv:hep-ex/0306006 |
backpressure ( bp ) routing is a well - established framework for distributed routing and scheduling in wireless multi - hop networks. however, the basic bp scheme suffers from poor end - to - end delay due to the drawbacks of slow startup, random walk, and the last packet problem. biased bp with shortest path awareness can address the first two drawbacks, and sojourn time - based backlog metrics were proposed for the last packet problem. furthermore, these bp variations require no additional signaling overhead in each time step compared to the basic bp. in this work, we further address three long - standing challenges associated with the aforementioned low - cost bp variations, including optimal scaling of the biases, bias maintenance under mobility, and incorporating sojourn time awareness into biased bp. our analysis and experimental results show that proper scaling of biases can be achieved with the help of common link features, which can effectively reduce end - to - end delay of bp by mitigating the random walk of packets under low - to - medium traffic, including the last packet scenario. in addition, our low - overhead bias maintenance scheme is shown to be effective under mobility, and our bio - inspired sojourn time - aware backlog metric is demonstrated to be more efficient and effective for the last packet problem than existing approaches when incorporated into biased bp. | arxiv:2310.04364 |
a normal mode analysis for proca fields in the anti - de sitter ( ads ) spacetime is given. it is found that the equations for the proca field can be decoupled analytically. this is performed by changing the basis of the vector spherical harmonics ( vsh ) decomposition. the normal modes and the normal mode frequencies of the proca equation in the ads spacetime are then analytically determined. it is also shown that the maxwell field can be recovered by taking the massless limit of the proca field with care so that the nonphysical gauge modes are eliminated. | arxiv:2301.10248 |
the objective of this work is to report on the modifications in air shower development due to muon bremsstrahlung and muonic pair production. in order to do that we have implemented new muon bremsstrahlung and muonic pair production procedures in the aires air shower simulation system, and have used it to simulate ultra high energy showers in different conditions. the influence of the mentioned processes in the global development of the air shower is important for primary particles of large zenith angles, while they do not introduce significant changes in the position of the shower maximum. | arxiv:astro-ph/0006108 |
this paper presents a stochastic, model predictive control ( mpc ) algorithm that leverages short - term probabilistic forecasts for dispatching and rebalancing autonomous mobility - on - demand systems ( amod, i. e. fleets of self - driving vehicles ). we first present the core stochastic optimization problem in terms of a time - expanded network flow model. then, to ameliorate its tractability, we present two key relaxations. first, we replace the original stochastic problem with a sample average approximation ( saa ), and characterize the performance guarantees. second, we separate the controller into two separate parts to address the task of assigning vehicles to the outstanding customers separate from that of rebalancing. this enables the problem to be solved as two totally unimodular linear programs, and thus easily scalable to large problem sizes. finally, we test the proposed algorithm in two scenarios based on real data and show that it outperforms prior state - of - the - art algorithms. in particular, in a simulation using customer data from didi chuxing, the algorithm presented here exhibits a 62. 3 percent reduction in customer waiting time compared to state of the art non - stochastic algorithms. | arxiv:1804.11074 |
i discuss the problem of constructing an effective low - energy theory in the vicinity of a resonance or a bound state. the focus is on the example of the $ \ delta ( 1232 ) $, the lightest resonance in the nucleon sector. recent developments of the chiral effective - field theory in the $ \ delta $ - resonance region are briefly reviewed. i conclude with a comment on the merits of the manifestly covariant formulation of chiral eft in the baryon sector. | arxiv:hep-ph/0612303 |
dark matter particles gravitationally bound to our galaxy should exhibit a characteristic speed distribution limited by their escape velocity at the position of the earth ( $ v _ { esc } \ simeq $ 550 km / s ). an ongoing search for anomalous cosmic rays at earth, kinematically similar to cold dark matter, is described. the technique can discriminate between these and known slow - moving particles such as neutrons, would be sensitive to telltale signatures from presently unexplored candidates, and offers the possibility of identifying the mediating type of interaction ( nuclear vs. electron recoils ). studies of background identification and abatement in a shallow underground site are presented. the expected reach of the method is discussed, and illustrated by obtaining the first limits for dark matter particles lighter than 100 mev / c $ ^ { 2 } $ interacting via nuclear recoils. | arxiv:1805.02646 |
we consider quadratic, nonmonotone generalized nash equilibrium problems with symmetric interactions among the agents. albeit this class of games is known to admit a potential function, its formal expression can be unavailable in several real - world applications. for this reason, we propose a two - layer nash equilibrium seeking scheme in which a central coordinator exploits noisy feedback from the agents to design personalized incentives for them. by making use of those incentives, the agents compute a solution to an extended game, and then return feedback measures to the coordinator. we show that our algorithm returns an equilibrium if the coordinator is endowed with standard learning policies, and corroborate our results on a numerical instance of a hypomonotone game. | arxiv:2111.03854 |
the neomycin resistance cassette ( neo + ) is commonly inserted in the genome of mice to generate knock - out ( ko ) models. the effect of gene deletion on social behaviors in mice is controversial between studies using different neo + and neo - mouse lines, particularly arc / arg3. 1 ko lines. in this study, we identified severe maternal behavior impairments in neo +, but not neo - arc / arg3. 1 ko dams. these deficits resulted from reduced sociability and abnormal social information processing in neo + arc / arg3. 1 ko dams, exacerbated by social communication impairments in pups. the expression of the neo cassette product did not cause cytotoxicity, but led to altered erk signaling, gene expression, and oxytocin system. however, oxytocin administration did not improve social impairments in neo + arc / arg3. 1 ko animals. interestingly, early social environment enrichment enhanced social interaction with familiar, but not unfamiliar conspecifics or maternal behavior. overall, our findings reveal a major impact of the neo cassette on behaviors, particularly social behaviors, in arc / arg3. 1 ko mice, underscoring the need to re - examine phenotypes of animal models carrying the neo cassette in neuroscience research. | arxiv:2505.03339 |
context. water together with o2 are important gas phase ingredients to cool dense gas in order to form stars. on dust grains, h2 o is an important constituent of the icy mantle in which a complex chemistry is taking place, as revealed by hot core observations. the formation of water can occur on dust grain surfaces, and can impact gas phase composition. aims. the formation of molecules such as oh, h2 o, ho2, h2 o2, as well as their deuterated forms and o2 and o3 is studied in order to assess how the chemistry varies in different astrophysical environments, and how the gas phase is affected by grain surface chemistry. methods. we use monte carlo simulations to follow the formation of molecules on bare grains as well as the fraction of molecules released into the gas phase. we consider a surface reaction network, based on gas phase reactions, as well as uv photo - dissociation of the chemical species. results. we show that grain surface chemistry has a strong impact on gas phase chemistry, and that this chemistry is very different for different dust grain temperatures. low temperatures favor hydrogenation, while higher temperatures favor oxygenation. also, uv photons dissociate the molecules on the surface, that can reform subsequently. the formation - destruction cycle increases the amount of species released into the gas phase. we also determine the time scales to form ices in diffuse and dense clouds, and show that ices are formed only in shielded environments, as supported by observations. | arxiv:1007.1061 |
modern semantic parsers suffer from two principal limitations. first, training requires expensive collection of utterance - program pairs. second, semantic parsers fail to generalize at test time to new compositions / structures that have not been observed during training. recent research has shown that automatic generation of synthetic utterance - program pairs can alleviate the first problem, but its potential for the second has thus far been under - explored. in this work, we investigate automatic generation of synthetic utterance - program pairs for improving compositional generalization in semantic parsing. given a small training set of annotated examples and an " infinite " pool of synthetic examples, we select a subset of synthetic examples that are structurally - diverse and use them to improve compositional generalization. we evaluate our approach on a new split of the schema2qa dataset, and show that it leads to dramatic improvements in compositional generalization as well as moderate improvements in the traditional i. i. d setup. moreover, structurally - diverse sampling achieves these improvements with as few as 5k examples, compared to 1m examples when sampling uniformly at random - - a 200x improvement in data efficiency. | arxiv:2109.02575 |
we review hodge structures, relating filtrations, galois theory and jordan - holder structures. the prototypical case of periods of riemann surfaces is compared with the galois - artin framework of algebraic numbers. | arxiv:2105.13115 |
detailed fluctuation theorems are statements about the probability distribution for the stochastic entropy production along a trajectory. it involves the consideration of a suitably transformed dynamics, such as the time reversed, the adjoint, or a combination of these. we identify specific, typically unique, initial conditions, called echo states, for which the final probability distribution of the transformed dynamics reproduces the initial distribution. in this case the detailed fluctuation theorems relate the stochastic entropy production of the direct process to that of the transformed one. we illustrate our results by an explicit analytical calculation and numerical simulations for a modulated two - state quantum dot. | arxiv:1405.6064 |
we present a simple, redshift - independent analytic model that explains the local fundamental metallicity relation ( fmr ), taking into account the physical processes of star formation, inflow of metal - poor intergalactic medium ( igm ) gas, and the outflow of metal rich interstellar medium ( ism ) gas. we show that the physics of the fmr can be summarised as follows : for massive galaxies with stellar mass m _ * > = 10 ^ 11 solar masses, ism metal enrichment due to star formation is compensated by inflow of metal poor igm gas, leading to a constant value of the gas metallicity with star formation rate ( sfr ) ; outflows are rendered negligible as a result of the large potential wells of these galaxies. on the other hand, as a result of their smaller sfr, less massive galaxies produce less heavy elements that are also more efficiently ejected due to their shallow potential wells ; as a result, for a given m _ *, the gas metallicity decreases with sfr. for such galaxies, the outflow efficiency determines both the slope, and the knee of the metallicity - sfr relation. without changing any parameters, this simple model is also successfully matched to the gas fraction - gas metallicity relation observed for a sample of about 260 nearby galaxies. | arxiv:1202.4770 |
co - exploration of an optimal neural architecture and its hardware accelerator is an approach of rising interest which addresses the computational cost problem, especially in low - profile systems. the large co - exploration space is often handled by adopting the idea of differentiable neural architecture search. however, despite the superior search efficiency of the differentiable co - exploration, it faces a critical challenge of not being able to systematically satisfy hard constraints such as frame rate. to handle the hard constraint problem of differentiable co - exploration, we propose hdx, which searches for hard - constrained solutions without compromising the global design objectives. by manipulating the gradients in the interest of the given hard constraint, high - quality solutions satisfying the constraint can be obtained. | arxiv:2301.09312 |
human memory is inherently prone to forgetting. to address this, multimodal embedding models have been introduced, which transform diverse real - world data into a unified embedding space. these embeddings can be retrieved efficiently, aiding mobile users in recalling past information. however, as model complexity grows, so do its resource demands, leading to reduced throughput and heavy computational requirements that limit mobile device implementation. in this paper, we introduce recall, a novel on - device multimodal embedding system optimized for resource - limited mobile environments. recall achieves high - throughput, accurate retrieval by generating coarse - grained embeddings and leveraging query - based filtering for refined retrieval. experimental results demonstrate that recall delivers high - quality embeddings with superior throughput, all while operating unobtrusively with minimal memory and energy consumption. | arxiv:2409.15342 |
we consider small ballistic quantum dots weakly coupled to the leads in the chaotic regime and look for significant spin - orbit effects. we find that these effects can become quite prominent in the vicinity of degeneracies of many - body energies. we illustrate the idea by considering a case where the intrinsic exchange term - js ^ 2 brings singlet and triplet many - body states near each other, while an externally tunable zeeman term then closes the gap between the singlet and the one of the triplet states ( with spin projection parallel the external field ). near this degeneracy, the spin - orbit coupling leads to a striking temperature dependence of the conductance, with observable effects of order unity at temperatures lower than the strength of the spin - orbit coupling. under favorable circumstances, spelled out in the paper, these order unity effects in the conductance persist to temperatures much higher than the spin - orbit coupling strength. our conclusions are unaffected by the presence of non - universal perturbations. we suggest a class of experiments to explore this regime. | arxiv:cond-mat/0609460 |
we identify the group of framed diffeomorphisms of the torus as a semi - direct product of the torus with the braid group on 3 strands ; we also identify the topological monoid of framed local - diffeomorphisms of the torus in similar terms. it follows that the framed mapping class group is this braid group. we show that the group of framed diffeomorphisms of the torus acts on twice - iterated hochschild homology, and explain how this recovers a host of familiar symmetries. in the case of cartesian monoidal structures, we show that this action extends to the monoid of framed local - diffeomorphisms of the torus. based on this, we propose a definition of an unstable secondary cyclotomic structure, and show that iterated hochschild homology possesses such in the cartesian monoidal setting. | arxiv:2111.08798 |
the miniaturized detector for application in space ( midas ) is a compact device with dimensions 5 x 5 x 1 cm3 which combines position sensitive si detectors and a fast neutrons spectrometer. midas is developed with purpose to act as a linear energy transfer ( let ) spectrometer for the charged particles and measure dose and dose equivalent from both charged particles and neutrons. it is based on fully depleted monolithic active si pixel sensors for the charged track and energy deposition measurements, while a plastic scintillator read out by a silicon photomultiplier is used to determine energy depositions from fast neutrons. a simulation study of the detector response in galactic cosmic ray ( gcr ) radiation fields with the aid of geant4 has been performed. energy depositions and hit pixel addresses have been used to reconstruct tracks and calculate let spectra. a method to calculate $ let \ infty $ in water from the measured let has been elaborated. dose rate in water and dose equivalent rate have been calculated. the energy and particle composition of the radiation field produced by the interaction of gcr with the al walls of a spacecraft model has been determined and the response of midas in this radiation field has been investigated. | arxiv:2202.06920 |
carter, jelsovsky, kamada, langford and saito have defined an invariant of classical links associated to each element of the second cohomology of a finite quandle. we study these invariants for alexander quandles of the form z [ t, t ^ { - 1 } ] / ( p, t ^ 2 + kappa t + 1 ), where p is a prime number and t ^ 2 + kappa t + 1 is irreducible modulo p. for each such quandle, there is an invariant with values in the group ring z [ c _ p ] of a cyclic group of order p. we shall show that the values of this invariant all have the form gamma _ p ^ r p ^ { 2s } for a fixed element gamma _ p of z [ c _ p ] and integers r > = 0 and s > 0. we also describe some machine computations, which lead us to conjecture that the invariant is determined by the alexander module of the link. this conjecture is verified for all torus and two - bridge knots. | arxiv:math/0207099 |
text - to - image diffusion models often exhibit biases toward specific demographic groups, such as generating more males than females when prompted to generate images of engineers, raising ethical concerns and limiting their adoption. in this paper, we tackle the challenge of mitigating generation bias towards any target attribute value ( e. g., " male " for " gender " ) in diffusion models while preserving generation quality. we propose fairgen, an adaptive latent guidance mechanism which controls the generation distribution during inference. in fairgen, a latent guidance module dynamically adjusts the diffusion process to enforce specific attributes, while a memory module tracks the generation statistics and steers latent guidance to align with the targeted fair distribution of the attribute values. further, given the limitations of existing datasets in comprehensively assessing bias in diffusion models, we introduce a holistic bias evaluation benchmark hbe, covering diverse domains and incorporating complex prompts across various applications. extensive evaluations on hbe and stable bias datasets demonstrate that fairgen outperforms existing bias mitigation approaches, achieving substantial bias reduction ( e. g., 68. 5 % gender bias reduction on stable diffusion 2 ). ablation studies highlight fairgen ' s ability to flexibly and precisely control generation distribution at any user - specified granularity, ensuring adaptive and targeted bias mitigation. | arxiv:2503.01872 |
recently maldacena and strominger found that the calculation of greybody factors for $ d = 5 $ black holes carrying three u ( 1 ) charges gives striking new evidence for their description as multiply wound effective strings. here we show that a similar result holds for $ d = 4 $ black holes with four $ u ( 1 ) $ charges. in this case the effective string may be thought of as the triple intersection of the 5 - branes in m - theory compactified on $ t ^ 7 $. | arxiv:hep-th/9609076 |
we consider the problem of generating rankings that are fair towards both users and item producers in recommender systems. we address both usual recommendation ( e. g., of music or movies ) and reciprocal recommendation ( e. g., dating ). following concepts of distributive justice in welfare economics, our notion of fairness aims at increasing the utility of the worse - off individuals, which we formalize using the criterion of lorenz efficiency. it guarantees that rankings are pareto efficient, and that they maximally redistribute utility from better - off to worse - off, at a given level of overall utility. we propose to generate rankings by maximizing concave welfare functions, and develop an efficient inference procedure based on the frank - wolfe algorithm. we prove that unlike existing approaches based on fairness constraints, our approach always produces fair rankings. our experiments also show that it increases the utility of the worse - off at lower costs in terms of overall utility. | arxiv:2110.15781 |
discovering causal genetic variants from large genetic association studies poses many difficult challenges. assessing which genetic markers are involved in determining trait status is a computationally demanding task, especially in the presence of gene - gene interactions. a non - parametric bayesian approach in the form of a bayesian neural network is proposed for use in analyzing genetic association studies. demonstrations on synthetic and real data reveal they are able to efficiently and accurately determine which variants are involved in determining case - control status. using graphics processing units ( gpus ) the time needed to build these models is decreased by several orders of magnitude. in comparison with commonly used approaches for detecting genetic interactions, bayesian neural networks perform very well across a broad spectrum of possible genetic relationships while having the computational efficiency needed to handle large datasets. | arxiv:1404.3989 |
we study the non - thermal emission from the interaction between magnetized jupiter - like exoplanets and the wind from their host star. the supersonic motion of planets through the wind forms a bow shock that accelerates electrons which produces non - thermal radiation across a broad wavelength range. we discuss three wind mass loss rates : $ \ dot { m } _ { \ rm w } \ sim10 ^ { - 14 } $, $ 10 ^ { - 9 } $, $ 10 ^ { - 6 } \, m _ { \ odot } \, \ rm yr ^ { - 1 } $ corresponding to solar - type, t tauri and massive o / b type stars, respectively. we find that the expected radio synchrotron emission from a jupiter - like planet is detectable by the jansky very large array and the square kilometer array at ~ 1 - 10 ghz out to a distance ~ 100 pc, whereas the infrared emission is detectable by the james webb space telescope out to a similar distance. inverse compton scattering of the stellar radiation results in x - ray emission detectable by chandra x - ray observatory out to ~ 150 pc. finally, we apply our model to the upper limit constraints on v380 tau, the first star - hot jupiter system observed in radio wavelength. our bow shock model provides constraints on the magnetic field, the interplanetary medium and the non - thermal emission efficiency in v380 tau. | arxiv:1902.05165 |
we present tokenflow, a novel unified image tokenizer that bridges the long - standing gap between multimodal understanding and generation. prior research attempt to employ a single reconstruction - targeted vector quantization ( vq ) encoder for unifying these two tasks. we observe that understanding and generation require fundamentally different granularities of visual information. this leads to a critical trade - off, particularly compromising performance in multimodal understanding tasks. tokenflow addresses this challenge through an innovative dual - codebook architecture that decouples semantic and pixel - level feature learning while maintaining their alignment via a shared mapping mechanism. this design enables direct access to both high - level semantic representations crucial for understanding tasks and fine - grained visual features essential for generation through shared indices. our extensive experiments demonstrate tokenflow ' s superiority across multiple dimensions. leveraging tokenflow, we demonstrate for the first time that discrete visual input can surpass llava - 1. 5 13b in understanding performance, achieving a 7. 2 \ % average improvement. for image reconstruction, we achieve a strong fid score of 0. 63 at 384 * 384 resolution. moreover, tokenflow establishes state - of - the - art performance in autoregressive image generation with a geneval score of 0. 55 at 256 * 256 resolution, achieving comparable results to sdxl. | arxiv:2412.03069 |
high - power hadron accelerators have strict limits on fractional beam loss. in principle, once a high - quality beam is set up in an acceptable state, beam loss should remain steady. however, in practice, there are many trips in operational machines, owing to excessive beam loss. this paper deals with monitoring equipment health to identify precursor signals that indicate an issue with equipment that will lead to unacceptable beam loss. to this end, a variety of equipment and beam signal measurements are described. in particular, several operational examples from the spallation neutron source ( sns ) of deteriorating equipment functionality leading to beam loss are reported. | arxiv:1608.02826 |
laboratory experiments in which synthetic, partially molten rock is subjected to forced deformation provide a context for testing hypotheses about the dynamics and rheology of the mantle. here our hypothesis is that the aggregate viscosity of partially molten mantle is anisotropic, and that this anisotropy arises from deviatoric stresses in the rock matrix. we formulate a model of pipe poiseuille flow based on theory by takei and holtzman [ 2009a ] and takei and katz [ 2013 ]. pipe poiseuille is a configuration that is accessible to laboratory experimentation but for which there are no published results. we analyse the model system through linearised analysis and numerical simulations. this analysis predicts two modes of melt segregation : migration of melt from the centre of the pipe toward the wall and localisation of melt into high - porosity bands that emerge near the wall, at a low angle to the shear plane. we compare our results to those of takei and katz [ 2013 ] for plane poiseuille flow ; we also describe a new approximation of radially varying anisotropy that improves the self - consistency of models over those of takei and katz [ 2013 ]. this study provides a set of baseline, quantitative predictions to compare with future laboratory experiments on forced pipe poiseuille flow of partially molten mantle. | arxiv:1404.6366 |
in this paper we study the incompressible inviscid limit for a compressible micro - polar model. we prove that the weak solution of the compressible micro - polar system converges to the solution of the navier - stokes equations ( euler equations ) in the limit of small mach number ( and vanishing viscosity ). | arxiv:2107.08810 |
this paper quantifies the intuitive observation that adding noise reduces available information by means of non - linear strong data processing inequalities. consider the random variables $ w \ to x \ to y $ forming a markov chain, where $ y = x + z $ with $ x $ and $ z $ real - valued, independent and $ x $ bounded in $ l _ p $ - norm. it is shown that $ i ( w ; y ) \ le f _ i ( i ( w ; x ) ) $ with $ f _ i ( t ) < t $ whenever $ t > 0 $, if and only if $ z $ has a density whose support is not disjoint from any translate of itself. a related question is to characterize for what couplings $ ( w, x ) $ the mutual information $ i ( w ; y ) $ is close to maximum possible. to that end we show that in order to saturate the channel, i. e. for $ i ( w ; y ) $ to approach capacity, it is mandatory that $ i ( w ; x ) \ to \ infty $ ( under suitable conditions on the channel ). a key ingredient for this result is a deconvolution lemma which shows that post - convolution total variation distance bounds the pre - convolution kolmogorov - smirnov distance. explicit bounds are provided for the special case of the additive gaussian noise channel with quadratic cost constraint. these bounds are shown to be order - optimal. for this case simplified proofs are provided leveraging gaussian - specific tools such as the connection between information and estimation ( i - mmse ) and talagrand ' s information - transportation inequality. | arxiv:1512.06429 |
the seiberg - witten solution of n = 2 supersymmetric su ( 2 ) gauge theories with matter is analysed as an isomonodromy problem. we show that the holomorphic section describing the effective action can be deformed by moving its singularities on the moduli space while keeping their monodromies invariant. well - known examples of isomonodromic sections are given by the correlators of two - dimensional rational conformal field theories - - the conformal blocks. the seiberg - witten section similarly admits the operations of braiding and fusing of its singularities, which obey the yang - baxter and pentagonal identities, respectively. using them, we easily find the complete expressions of the monodromies with affine term, and the full quantum numbers of the bps spectrum. while the braiding describes the quark - monopole transmutation, the fusing implies the superconformal points in the moduli space. in the simplest case of three singularities, the supersymmetric sections are directly related to the conformal blocks of the logarithmic minimal models. | arxiv:hep-th/9710248 |
the review is aimed at highlighting the aspects of topological superconductivity in the absence of spin - orbit interaction in two - dimensional systems with long - range non - collinear spin ordering or magnetic skyrmions. another purpose is to give a brief introduction to the new concept of topological superconductivity, i. e. higher - order topology in two - dimensional systems including spin - orbit coupled structures. the formation of majorana modes due to magnetic textures is discussed. the role of effective triplet pairings and odd fermion parity of the ground state wave function in different systems is emphasized. we describe the peculiarities of the magnetic skyrmions, leading to the formation of the majorana modes and defects on which the modes are localized. the problem of braiding in the two - dimensional systems, especially in higher - order topological superconductors, is considered. | arxiv:2109.03169 |
we investigate the strong coupling region of the topological sector of the two - dimensional $ \ phi ^ 4 $ theory. using discrete light cone quantization ( dlcq ), we extract the masses of the lowest few excitations and observe level crossings. to understand this phenomena, we evaluate the expectation value of the integral of the normal ordered $ \ phi ^ 2 $ operator and we extract the number density of constituents in these states. a coherent state variational calculation confirms that the number density for low - lying states above the transition coupling is dominantly that of a kink - antikink - kink state. the fourier transform of the form factor of the lowest excitation is extracted which reveals a structure close to a kink - antikink - kink profile. thus, we demonstrate that the structure of the lowest excitations becomes that of a kink - antikink - kink configuration at moderately strong coupling. we extract the critical coupling for the transition of the lowest state from that of a kink to a kink - antikink - kink. we interpret the transition as evidence for the onset of kink condensation which is believed to be the physical mechanism for the symmetry restoring phase transition in two - dimensional $ \ phi ^ 4 $ theory. | arxiv:hep-th/0504094 |
pre - trained conditional diffusion models have demonstrated remarkable potential in image editing. however, they often face challenges with temporal consistency, particularly in the talking head domain, where continuous changes in facial expressions intensify the level of difficulty. these issues stem from the independent editing of individual images and the inherent loss of temporal continuity during the editing process. in this paper, we introduce follow your motion ( fym ), a generic framework for maintaining temporal consistency in portrait editing. specifically, given portrait images rendered by a pre - trained 3d gaussian splatting model, we first develop a diffusion model that intuitively and inherently learns motion trajectory changes at different scales and pixel coordinates, from the first frame to each subsequent frame. this approach ensures that temporally inconsistent edited avatars inherit the motion information from the rendered avatars. secondly, to maintain fine - grained expression temporal consistency in talking head editing, we propose a dynamic re - weighted attention mechanism. this mechanism assigns higher weight coefficients to landmark points in space and dynamically updates these weights based on landmark loss, achieving more consistent and refined facial expressions. extensive experiments demonstrate that our method outperforms existing approaches in terms of temporal consistency and can be used to optimize and compensate for temporally inconsistent outputs in a range of applications, such as text - driven editing, relighting, and various other applications. | arxiv:2503.22225 |
bound states in the continuum ( bics ), an emerging type of long - lived resonances different from the cavity - based ones, have been explored in several classical systems, including photonic crystals and surface acoustic waves. here, we reveal symmetry - protected mechanical bics in the structure of slab - on - substrate optomechanical crystals. using a group theory approach, we identified all the mechanical bics at the $ \ gamma $ point in optomechanical crystals with $ c _ { 4v } $ and $ c _ { 6v } $ symmetries as examples, and analyzed their coupling with the co - localized optical bics and guided resonances due to both moving boundary and photo - elastic effects. we verified the theoretical analysis with numerical simulations of specific optomechanical crystals which support substantial optomechanical interactions between the mechanical bics and optical resonances. due to the unique features of high - $ q $, large - size mechanical bics and substrate - enabled thermal dissipation, this architecture of slab - on - substrate optomechanical crystals might be useful for exploring macroscopic quantum mechanical physics and enabling new applications such as high - throughput sensing and free - space beam steering. | arxiv:1902.00614 |
we investigate how representing active regions with bipolar magnetic regions ( bmrs ) affects the end - of - cycle polar field predicted by the surface flux transport model. our study is based on a new database of bmrs derived from the sdo / hmi active region patch data between 2010 and 2020. an automated code is developed for fitting each active region patch with a bmr, matching both the magnetic flux and axial dipole moment of the region and removing repeat observations of the same region. by comparing the predicted evolution of each of the 1090 bmrs with the predicted evolution of their original active region patches, we show that the bipolar approximation leads to a 24 % overestimate of the net axial dipole moment, given the same flow parameters. this is caused by neglecting the more complex multipolar and / or asymmetric magnetic structures of many of the real active regions, and may explain why previous flux transport models had to reduce bmr tilt angles to obtain realistic polar fields. our bmr database and the python code to extract it are freely available. | arxiv:2008.03203 |
to every hyperelliptic curve one can assign the periods of the integrals over the holomorphic and the meromorphic differentials. by comparing two representations of the so - called projective connection it is possible to reexpress the latter periods by the first. this leads to expressions including only the curve ' s parameters $ \ lambda _ j $ and modular forms. by a change of basis of the meromorphic differentials one can further simplify this expression. we discuss the advantages of these explicitly given bases, which we call baker and klein basis, respectively. | arxiv:1512.06765 |
we propose a discontinuous finite element method for small strain elasticity allowing for cohesive zone modeling. the method yields a seamless transition between the discontinuous galerkin method and classical cohesive zone modeling. some relevant numerical examples are presented. | arxiv:1502.01119 |
this study investigates the behavior of microbubbles generated by the local heating of an ethanol / water mixture and the surrounding flow. the mixture is photothermally heated by focusing a continuous - wave laser on a fesi $ _ 2 $ thin film. although the liquid is not degassed, vapor - rich bubbles are stably generated in an ethanol concentration range of 1. 5 - 50 wt % the vapor - rich bubbles absorb the air dissolved in the surrounding liquid and exhale it continuously as air - rich bubbles $ \ sim $ 1 { \ mu } m in diameter. for the same ethanol concentration range, the solutal - marangoni force becomes dominant relative to the thermal - marangoni force, and the air - rich bubbles are pushed away from the high - temperature region in the fluid toward the low - temperature region. further, it was experimentally demonstrated that marangoni forces do not significantly affect the surface of vapor - rich bubbles generated in ethanol / water mixtures, and they produce a flow from the high - temperature to the low - temperature region on the vapor - rich bubbles, which moves the exhaled air - rich bubbles away from the vapor - rich bubbles near the heat source. these effects prevent the vapor - rich and exhaled air - rich bubbles from recombining, thereby resulting in the long - term stability of the former. moreover, the flow produced by the vapor - rich bubbles in the non - degassed 0 - 20 wt % ethanol / water mixture was stronger than that in degassed water. the maximum flow speed is achieved for an ethanol concentration of 5 wt %, which is 6 - 11 times higher than that when degassed water is utilized. the ethanol / water mixture produces vapor - rich bubbles without a degassing liquid and enhances the flow speed generated by the vapor - rich bubbles. this flow is expected to apply to driving and mixing microfluids. | arxiv:2405.11731 |
we report the archival discovery of lyman - $ \ alpha $ emission from the bright ultraviolet galaxy y002 at $ z = 7. 677 $, spectroscopically confirmed by its ionized carbon [ cii ] 158 $ \ mu $ m emission line. the ly $ \ alpha $ line is spatially associated with the rest - frame uv stellar emission ( $ m _ { \ rm uv } $ ~ - 22, 2x brighter than $ m ^ \ star _ { \ rm uv } $ ) and it appears offset from the peak of the extended [ cii ] emission at the current ~ 1 " spatial resolution. we derive an estimate of the unobscured sfr ( uv ) = $ ( 22 \ pm1 ) \, m _ \ odot $ yr $ ^ { - 1 } $ and set an upper limit of sfr ( ir ) $ < 15 \, m _ \ odot $ yr $ ^ { - 1 } $ from the far - infrared wavelength range, which globally place y002 on the sfr ( uv + ir ) - l ( [ cii ] ) correlation observed at lower redshifts. in terms of velocity, the peak of the ly $ \ alpha $ emission is redshifted by $ \ delta v $ ( ly $ \ alpha $ ) ~ 500 km s $ ^ { - 1 } $ from the systemic redshift set by [ cii ] and a high - velocity tail extends to up to ~ 1000 km s $ ^ { - 1 } $. the velocity offset is up to ~ 3. 5x higher than the average estimate for similarly uv - bright emitters at z ~ 6 - 7, which might suggest that we are witnessing the merging of two clumps. a combination of strong outflows and the possible presence of an extended ionized bubble surrounding y002 would likely facilitate the escape of copious ly $ \ alpha $ light, as indicated by the large equivalent width ew ( ly $ \ alpha $ ) = $ 24 ^ { + 5 } _ { - 6 } $ \ r { a }. assuming that [ cii ] traces the neutral hydrogen, we estimate a hi gas fraction of $ m ( { \ rm hi } ) / m _ \ star \ gtrsim8 $ for y002 as a system and speculate that patches of high hi column densities could contribute to explain the observed spatial offsets between ly $ \ alpha $ and [ ci | arxiv:2203.03657 |
federated learning is generally used in tasks where labels are readily available ( e. g., next word prediction ). relaxing this constraint requires design of unsupervised learning techniques that can support desirable properties for federated training : robustness to statistical / systems heterogeneity, scalability with number of participants, and communication efficiency. prior work on this topic has focused on directly extending centralized self - supervised learning techniques, which are not designed to have the properties listed above. to address this situation, we propose orchestra, a novel unsupervised federated learning technique that exploits the federation ' s hierarchy to orchestrate a distributed clustering task and enforce a globally consistent partitioning of clients ' data into discriminable clusters. we show the algorithmic pipeline in orchestra guarantees good generalization performance under a linear probe, allowing it to outperform alternative techniques in a broad range of conditions, including variation in heterogeneity, number of clients, participation ratio, and local epochs. | arxiv:2205.11506 |
intelligent transportation systems ( itss ) providing vehicle - related statistical data are one of the key components for future smart cities. in this context, knowledge about the current traffic flow is used for travel time reduction and proactive jam avoidance by intelligent traffic control mechanisms. in addition, the monitoring and classification of vehicles can be used in the field of smart parking systems. the required data is measured using networks with a wide range of sensors. nevertheless, in the context of smart cities no existing solution for traffic flow detection and vehicle classification is able to guarantee high classification accuracy, low deployment and maintenance costs, low power consumption and a weather - independent operation while respecting privacy. in this paper, we propose a radiobased approach for traffic flow detection and vehicle classification using signal attenuation measurements and machine learning algorithms. the results of comprehensive measurements in the field prove its high classification success rate of about 99 %. | arxiv:1801.03317 |
face alignment, which fits a face model to an image and extracts the semantic meanings of facial pixels, has been an important topic in the computer vision community. however, most algorithms are designed for faces in small to medium poses ( yaw angle is smaller than 45 degrees ), which lack the ability to align faces in large poses up to 90 degrees. the challenges are three - fold. firstly, the commonly used landmark face model assumes that all the landmarks are visible and is therefore not suitable for large poses. secondly, the face appearance varies more drastically across large poses, from the frontal view to the profile view. thirdly, labelling landmarks in large poses is extremely challenging since the invisible landmarks have to be guessed. in this paper, we propose to tackle these three challenges in an new alignment framework termed 3d dense face alignment ( 3ddfa ), in which a dense 3d morphable model ( 3dmm ) is fitted to the image via cascaded convolutional neural networks. we also utilize 3d information to synthesize face images in profile views to provide abundant samples for training. experiments on the challenging aflw database show that the proposed approach achieves significant improvements over the state - of - the - art methods. | arxiv:1804.01005 |
enhanced coherence in how $ _ { 10 } $ molecular spin qubits has been demonstrated by use of clock transitions ( cts ). more recently it was shown that, while operating at the cts, it was possible to use an electrical field to selectively address how $ _ { 10 } $ molecules pointing in a given direction, within a crystal that contains two kinds of identical but inversion - related molecules. herein we theoretically explore the possibility of employing the electric field to effect entangling two - qubit quantum gates among two neighbouring ct - protected how $ _ { 10 } $ qubits within a diluted crystal. we estimate the thermal evolution of $ t _ 1 $, $ t _ 2 $, find that cts are also optimal operating points from the point of view of phonons, and lay out how to combine a sequence of microwave and electric field pulses to achieve coherent control within a 2 - qubit operating space that is protected both from spin - bath and from phonon - bath decoherence. finally, we found a highly protected 1 - qubit subspace resulting from the interaction between two clock molecules. | arxiv:2204.09592 |
many electronic structure methods rely on the minimization of the energy of the system with respect to the one - body reduced density matrix ( 1 - rdm ). to formulate a minimization algorithm, the 1 - rdm is often expressed in terms of its eigenvectors via an orthonormal transformation and its eigenvalues. this transformation drastically alters the energy landscape. especially in 1 - rdm functional theory this means that the convexity of the energy functional is lost. we show that degeneracies in the occupation numbers can lead to additional critical points which are classified as saddle points. using a cayley or householder parametrization for the orthonormal transformation, no extra critical points arise. in case of given ' s rotations or the exponential, additional critical points can arise, which are of no concern in practical minimization. these findings provide an explanation for the success of recent minimization procedures using second - order information. | arxiv:2501.18996 |
the recent proliferation of smart home environments offers new and transformative circumstances for various domains with a commitment to enhancing the quality of life and experience. most of these environments combine different gadgets offered by multiple stakeholders in a dynamic and decentralized manner, which in turn presents new challenges from the perspective of digital investigation. in addition, a plentiful amount of data records got generated because of the day to day interactions between these gadgets and homeowners, which poses difficulty in managing and analyzing such data. the analysts should endorse new digital investigation approaches to tackle the current limitations in traditional approaches when used in these environments. the digital evidence in such environments can be found inside the records of logfiles that store the historical events occurred inside the smart home. threat hunting can leverage the collective nature of these gadgets to gain deeper insights into the best way for responding to new threats, which in turn can be valuable in reducing the impact of breaches. nevertheless, this approach depends mainly on the readiness of smart homeowners to share their own personal usage logs that have been extracted from their smart home environments. however, they might disincline to employ such service due to the sensitive nature of the information logged by their personal gateways. in this paper, we presented an approach to enable smart homeowners to share their usage logs in a privacy preserving manner. a distributed threat hunting approach has been developed to permit the composition of diverse threat classes without revealing the logged records to other involved parties. furthermore, a scenario was proposed to depict a proactive threat intelligence sharing for the detection of potential threats in smart home environments with some experimental results. | arxiv:1911.02174 |
an experimental platform operating at the level of individual quanta and providing strong light - matter coupling is a key requirement for quantum information processing. we report on narrowband light storage and retrieval as well as stationary light, based on electromagnetically induced transparency, for weak coherent light pulses down to the single - photon level with a signal - to - noise ratio of 59. the experiments were carried out with laser - cooled atoms loaded into a hollow - core photonic crystal fiber to provide strong light - matter coupling, thereby demonstrating the prospects for future quantum networks of such a platform. | arxiv:1906.05771 |
and last entries, and using markers and variables. the sutras create the impression that communication through the text was " only a part of the whole instruction. the rest of the instruction must have been transmitted by the so - called guru - shishya parampara, ' uninterrupted succession from teacher ( guru ) to the student ( sisya ), ' and it was not open to the general public " and perhaps even kept secret. the brevity achieved in a sutra is demonstrated in the following example from the baudhayana sulba sutra ( 700 bce ). the domestic fire - altar in the vedic period was required by ritual to have a square base and be constituted of five layers of bricks with 21 bricks in each layer. one method of constructing the altar was to divide one side of the square into three equal parts using a cord or rope, to next divide the transverse ( or perpendicular ) side into seven equal parts, and thereby sub - divide the square into 21 congruent rectangles. the bricks were then designed to be of the shape of the constituent rectangle and the layer was created. to form the next layer, the same formula was used, but the bricks were arranged transversely. the process was then repeated three more times ( with alternating directions ) in order to complete the construction. in the baudhayana sulba sutra, this procedure is described in the following words : ii. 64. after dividing the quadri - lateral in seven, one divides the transverse [ cord ] in three. ii. 65. in another layer one places the [ bricks ] north - pointing. according to filliozat, the officiant constructing the altar has only a few tools and materials at his disposal : a cord ( sanskrit, rajju, f. ), two pegs ( sanskrit, sanku, m. ), and clay to make the bricks ( sanskrit, istaka, f. ). concision is achieved in the sutra, by not explicitly mentioning what the adjective " transverse " qualifies ; however, from the feminine form of the ( sanskrit ) adjective used, it is easily inferred to qualify " cord. " similarly, in the second stanza, " bricks " are not explicitly mentioned, but inferred again by the feminine plural form of " north - pointing. " finally, the first stanza, never explicitly says that the first layer of bricks are oriented in the east – west direction, but that too is implied by the explicit mention of " north - pointing | https://en.wikipedia.org/wiki/Indian_mathematics |
we report small - scale clustering measurements from the primus spectroscopic redshift survey as a function of color and luminosity. we measure the real - space cross - correlations between 62, 106 primary galaxies with primus redshifts and a tracer population of 545, 000 photometric galaxies over redshifts from z = 0. 2 to z = 1. we separately fit a power - law model in redshift and luminosity to each of three independent color - selected samples of galaxies. we report clustering amplitudes at fiducial values of z = 0. 5 and l = 1. 5 l *. the clustering of the red galaxies is ~ 3 times as strong as that of the blue galaxies and ~ 1. 5 as strong as that of the green galaxies. we also find that the luminosity dependence of the clustering is strongly dependent on physical scale, with greater luminosity dependence being found between r = 0. 0625 mpc / h and r = 0. 25 mpc / h, compared to the r = 0. 5 mpc / h to r = 2 mpc / h range. moreover, over a range of two orders of magnitude in luminosity, a single power - law fit to the luminosity dependence is not sufficient to explain the increase in clustering at both the bright and faint ends at the smaller scales. we argue that luminosity - dependent clustering at small scales is a necessary component of galaxy - halo occupation models for blue, star - forming galaxies as well as for red, quenched galaxies. | arxiv:1502.01348 |
we show a counterexample to a conjecture of de bobadilla, luengo, melle - hern \ ' { a } ndez and n \ ' { e } methi on rational cuspidal projective plane curves. the counterexample is a tricuspidal curve of degree 8. on the other hand, we show that if the number of cusps is at most 2, then the original conjecture can be deduced from the recent results of borodzik and livingston and ( lattice cohomology ) computations of n \ ' emethi and rom \ ' an. then we formulate a ` simplified ' ( slightly weaker ) version, more in the spirit of the motivation of the original conjecture ( comparing index type numerical invariants ), and we prove it for all currently known rational cuspidal curves. we make all these identities and inequalities more transparent in the language of lattice cohomology of surgery 3 - manifolds $ s ^ 3 _ { - d } ( k ) $, where $ k $ is a connected sum of algebraic knots $ \ { k _ i \ } _ i $. finally, we prove that the zeroth lattice cohomology of this surgery manifold depends only on the multiset of multiplicities occurring in the multiplicity sequences describing the algebraic knots $ k _ i $. this result is closely related to the lattice - cohomological reformulation of the above mentioned theorems and conjectures, and provides new computational and comparison procedures. | arxiv:1405.0437 |
to understand how systems of star clusters have reached their presently observed properties constitutes a powerful probe into the physics of cluster formation, without needing to resort to high spatial resolution observations of individual cluster - forming regions ( cfrg ) in distant galaxies. in this contribution i focus on the mass - radius relation of cfrgs, how it can be uncovered by studying the gas expulsion phase of forming star clusters, and what the implications are. i demonstrate that, through the tidal field impact upon exposed star clusters, the cfrg mass - radius relation rules cluster infant weight - loss in dependence of cluster mass. the observational constraint of a time - invariant slope for the power - law young cluster mass function is robustly satisfied by cfrgs with a constant mean volume density. in contrast, a constant mean surface density would be conducive to the preferential destruction of high - mass clusters. a purely dynamical line - of - reasoning leads therefore to a conclusion consistent with star formation a process driven by a volume density threshold. developing this concept further, properties of molecular clumps and cfrgs naturally get dissociated. this allows to understand : ( i ) why the star cluster mass function is steeper than the molecular cloud ( clump ) mass function ; ( ii ) the presence of a massive star formation limit in the mass - size space of molecular structures. | arxiv:1107.3558 |
we investigate the limiting behavior of solutions to the inhomogeneous $ p $ - laplacian equation $ - \ delta _ p u = \ mu _ p $ subject to neumann boundary conditions. for right hand sides which are arbitrary signed measures we show that solutions converge to a kantorovich potential associated with the geodesic wasserstein - $ 1 $ distance. in the regular case with continuous right hand sides we characterize the limit as viscosity solution to an infinity laplacian / eikonal type equation. | arxiv:2112.07401 |
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