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we prove closed - form equations for the exact high - dimensional asymptotics of a family of first order gradient - based methods, learning an estimator ( e. g. m - estimator, shallow neural network,... ) from observations on gaussian data with empirical risk minimization. this includes widely used algorithms such as stochastic gradient descent ( sgd ) or nesterov acceleration. the obtained equations match those resulting from the discretization of dynamical mean - field theory ( dmft ) equations from statistical physics when applied to gradient flow. our proof method allows us to give an explicit description of how memory kernels build up in the effective dynamics, and to include non - separable update functions, allowing datasets with non - identity covariance matrices. finally, we provide numerical implementations of the equations for sgd with generic extensive batch - size and with constant learning rates. | arxiv:2210.06591 |
let g be a complex semisimple linear algebraic group, and x a wonderful g - variety. we determine the connected automorphism group of x and we calculate luna ' s invariants of x under its action. | arxiv:0802.4431 |
the quantum coherence of electrons can be probed by studying weak localization corrections to the conductivity. interaction effects lead to dephasing, with electron - electron interactions being the important intrinsic mechanism. a controversy exists whether or not the dephasing rate, as measured in a weak localization experiment, vanishes at low temperatures. we review the non - perturbative analysis of this question and some of the arguments which have been raised against it. the compact form of the presentation should make the derivation more transparent and accessible for discussions. we also compare with recent experiments. | arxiv:cond-mat/0110495 |
we introduce a computational technique for studying non - supersymmetric deformations of domain wall solutions of interest in ads / cft. we focus on the klebanov - strassler solution, which is dual to a confining gauge theory. from an analysis of asymptotics we find that there are three deformations that leave the ten - dimensional supergravity solution regular and preserve the global bosonic symmetries of the supersymmetric solution. also, we show that there are no regular near - extremal deformations preserving the global symmetries, as one might expect from the existence of a gap in the gauge theory. | arxiv:hep-th/0206098 |
electric transport and scanning tunneling spectrum ( sts ) have been investigated on polycrystalline samples of the new superconductor bi4o4s3. a weak insulating behavior in the resistive curve has been induced in the normal state when the superconductivity is suppressed by applying a magnetic field. interestingly, a kink appears on the temperature dependence of resistivity near 4 k at all high magnetic fields above 1 t when the bulk superconductivity is completely suppressed. this kink associated with the upper critical field as well as the wide range of excess conductance at low field and high temperature are explained as the possible evidence of strong superconducting fluctuation. from the tunneling spectra, a superconducting gap of about 3 mev is frequently observed yielding a ratio of 2 \ delta / ( kb * tc ) ~ 16. 6. this value is much larger than the one predicted by the bcs theory in the weak coupling regime ( 2 \ delta / ( kb * tc ) ~ 3. 53 ), which suggests the strong coupling superconductivity in the present system. furthermore, the gapped feature persists on the spectra until 14 k in the sts measurement, which suggests a prominent fluctuation region of superconductivity. such superconducting fluctuation can survive at very high magnetic fields, which are far beyond the critical fields for bulk superconductivity as inferred both from electric transport and tunneling measurements. | arxiv:1304.3354 |
agents are represented by nodes on a random graph ( e. g., small world or truncated power law ). each agent is endowed with a zero - mean random value that may be either positive or negative. all agents attempt to find relief, i. e., to reduce the magnitude of that initial value, to zero if possible, through exchanges. the exchange occurs only between agents that are linked, a constraint that turns out to dominate the results. the exchange process continues until a pareto equilibrium is achieved. only 40 % - 90 % of the agents achieved relief on small world graphs with mean degree between 2 and 40. even fewer agents achieved relief on scale - free like graphs with a truncated power law degree distribution. the rate at which relief grew with increasing degree was slow, only at most logarithmic for all of the graphs considered ; viewed in reverse, relief is resilient to the removal of links. | arxiv:physics/0612085 |
we define a simple obstruction to yu ' s property a that we call $ k $ - prisms. this structure allows for a straightforward proof that the space of persistence diagrams fails to have property a in a wasserstein metric. | arxiv:1902.02288 |
most clusters and groups of galaxies contain a giant elliptical galaxy in their centres which far outshines and outweighs normal ellipticals. the origin of these brightest cluster galaxies is intimately related to the collapse and formation of the cluster. using an n - body simulation of a cluster of galaxies in a hierarchical cosmological model, we show that galaxy merging naturally produces a massive, central galaxy with surface brightness and velocity dispersion profiles similar to observed bcg ' s. to enhance the resolution of the simulation, 100 dark halos at $ z = 2 $ are replaced with self - consistent disk + bulge + halo galaxy models following a tully - fisher relation using 100000 particles for the 20 largest galaxies and 10000 particles for the remaining ones. this technique allows us to analyze the stellar and dark matter components independently. the central galaxy forms through the merger of several massive galaxies along a filament early in the cluster ' s history. galactic cannibalism of smaller galaxies through dynamical friction over a hubble time only accounts for a small fraction of the accreted mass. the galaxy is a flattened, triaxial object whose long axis aligns with the primordial filament and the long axis of the cluster galaxy distribution agreeing with observed trends for galaxy - cluster alignment. | arxiv:astro-ph/9709102 |
recently, it was pointed out that soft masses of the supersymmetric gauge theories with extra dimensions tends to a flavor conserving point, which is a desirable scenario in gravity mediation models. we point out that in 6d we must consider the anomaly free condition in addition to the condition on the asymptotic freedom. from this, we find $ e _ 6 $, $ e _ 7 $ and $ e _ 8 $ are natural candidates in 6d. there is no su ( n ) model, but there exist two so ( 10 ) models and so ( 2n ) models ( one each for each $ n \ ge 6 $ ) satisfying these conditions. in 5 dimensions, there is no such condition on anomaly freedom, but the softening may not be enough. | arxiv:hep-ph/0212354 |
knowledge of relaxation processes is fundamental in glass science and technology because relaxation is intrinsically related to vitrification, tempering as well as to annealing and sev - eral applications of glasses. however, there are conflicting reports - - summarized here for different glasses - - on whether the structural relaxation time of glass can be calculated using the maxwell equation, which relates relaxation time with shear viscosity and shear modulus. hence, this study aimed to verify whether these two relaxation times are comparable. the structural relaxation kinetics of a lead metasilicate glass were studied by measuring the re - fractive index variation over time at temperatures between 5 and 25 k below the fictive temperature, which was initially set 5 k below the glass transition temperature. equilibrium shear viscosity was measured above and below the glass transition range, expanding the current knowledge by one order of magnitude. the kohlrausch equation described very well the experimental structural relaxation kinetics throughout the investigated temperature range and the kohlrausch exponent increased with temperature, in agreement with studies on other glasses. the experimental average structural relaxation times were much longer than the values computed from isostructural viscosity, as expected. still, they were less than one order of magnitude higher than the average relaxation time computed through the maxwell equation, which relies on equilibrium shear viscosity. thus, these results demon - strate that the structural relaxation process is not controlled by isostructural viscosity, and that equilibrium shear viscosity only provides a lower boundary for structural relaxation kinetics. | arxiv:2010.10554 |
( abridged ). in this paper, we present results from a large set of numerical simulations that demonstrate that h2 formation occurs rapidly in turbulent gas. starting with purely atomic hydrogen, large quantities of molecular hydrogen can be produced on timescales of 1 - - 2 myr, given turbulent velocity dispersions and magnetic field strengths consistent with observations. moreover, as our simulations underestimate the effectiveness of h2 self - shielding and dust absorption, we can be confident that the molecular fractions that we compute are strong lower limits on the true values. the formation of large quantities of h2 on the timescale required by rapid cloud formation models therefore appears to be entirely plausible. we also investigate the density and temperature distributions of gas in our model clouds. we show that the density probability distribution function is approximately log - normal, with a dispersion that agrees well with the prediction of padoan, nordlund & jones ( 1997 ). the temperature distribution is similar to that of a polytrope, with an effective polytropic index gamma _ eff \ simeq 0. 8, although at low gas densities, the scatter of the actual gas temperature around this mean value is considerable, and the polytropic approximation does not capture the full range of behaviour of the gas. | arxiv:astro-ph/0605121 |
we provide a glimpse of recent progress in meson physics made via qcd ' s dyson - schwinger equations with : a perspective on confinement and dynamical chiral symmetry breaking ( dcsb ) ; a pre ' cis on the physics of in - hadron condensates ; results for the masses of the \ pi, \ sigma, \ rho, a _ 1 mesons and their first - radial excitations ; and an illustration of the impact of dcsb on the pion form factor. | arxiv:1007.4318 |
we study capability of the ilc beam dump experiment to search for new physics, comparing the performance of the electron and positron beam dumps. the dark photon, axion - like particles, and light scalar bosons are considered as new physics scenarios, where all the important production mechanisms are included : electron - positron pair - annihilation, primakoff process, and bremsstrahlung productions. we find that the ilc beam dump experiment has higher sensitivity than past beam dump experiments, with the positron beam dump having slightly better performance for new physics particles which are produced by the electron - positron pair - annihilation. | arxiv:2105.13768 |
experimental results describing random, uni - directional, long crested, water waves over non - uniform bathymetry confirm the formation of stable coherent wave packages traveling with almost uniform group velocity. the waves are generated with jonswap spectrum for various steepness, height and constant period. a set of statistical procedures were applied to the experimental data, including the space and time variation of kurtosis, skewness, bfi, fourier and moving fourier spectra, and probability distribution of wave heights. stable wave packages formed out of the random field and traveling over shoals, valleys and slopes were compared with exact solutions of the nls equation resulting in good matches and demonstrating that these packages are very similar to deep water breathers solutions, surviving over the non - uniform bathymetry. we also present events of formation of rogue waves over those regions where the bfi, kurtosis and skewness coefficients have maximal values. | arxiv:2005.14193 |
context. deep spectroscopic surveys with the atacama large millimeter / submillimeter array ( alma ) have revealed that some of the brightest infrared sources in the sky correspond to concentrations of dusty star - forming galaxies ( dsfg ) at high redshift. among these, the spt2349 - 56 protocluster system at z = 4. 304 is amongst the most extreme examples due to its high source density and integrated star formation rate. aims. we conducted a deep lyman - $ \ alpha $ line emission survey around spt2349 - 56 using the multi - unit spectroscopic explorer ( muse ) at very large telescope ( vlt ) in order to characterize this uniquely dense environment. methods. taking advantage of the deep three - dimensional nature of this survey, we performed a sensitive search for lyman - $ \ alpha $ emitters ( laes ) toward the core and northern extension of the protocluster, which correspond to the brightest infrared regions in this field. using a smoothed narrowband image extracted from the muse datacube around the protocluster redshift, we searched for possible extended structures. results. we identify only three laes at z = 4. 3 in this field, in concordance with expectations for blank - fields, and an extended lyman - $ \ alpha $ structure spatially associated with core of the protocluster. all the previously - identified dsfgs in this field are undetected in lyman - $ \ alpha $ emission, consistent with the conspicuous dust obscuration in these systems. we find an extended lyman - $ \ alpha $ structure, about $ 60 \ times 60 $ kpc $ ^ { 2 } $ in size, and located 56 kpc west of the protocluster core. three dsfgs coincide spatially with the location of this structure. we conclude that either the three co - spatial dsfgs or the protocluster core itself are feeding ionizing photons to the lyman - $ \ alpha $ structure. | arxiv:2301.01328 |
we show via numerical simulation that kerr frequency combs can be generated in a nonlinear resonator characterized with normal group velocity dispersion ( gvd ). we find the spectral shape of the comb and temporal envelope of the corresponding optical pulses formed in the resonator. | arxiv:1111.3907 |
over the last decades the web has evolved from a human - human communication network to a network of complex human - machine interactions. an increasing amount of data is available as linked data which allows machines to " understand " the data, but rdf is not meant to be understood by humans. with jekyll rdf we present a method to close the gap between structured data and human accessible exploration interfaces by publishing rdf datasets as customizable static html sites. it consists of an rdf resource mapping system to serve the resources under their respective iri, a template mapping based on schema classes, and a markup language to define templates to render customized resource pages. using the template system, it is possible to create domain specific browsing interfaces for rdf data next to the linked data resources. this enables content management and knowledge management systems to serve datasets in a highly customizable, low effort, and scalable way to be consumed by machines as well as humans. | arxiv:2201.00618 |
hydrogen segregation to vacancies in the surface and subsurface layers of ( 111 ) and ( 100 ) surfaces of pd is studied in the density functional theory ( dft ) approach. adsorption energies and configurations of various clusters of h atoms at the vacancies are calculated. the adsorption energy varies for different sites in the vacancies with the distance to the surface from - 0. 26 ev ( close to that of the bulk clusters ) to - 0. 62 ev. enhanced binding is found for the sites above the pores produced by vacancies in the subsurface layer. for the ( 111 ) surface vacancy the most favorable for segregation are tetrahedral lattice sites, while for ( 100 ) octa - sites have higher binding energy. lattice relaxation effects are minor for the ( 111 ) surface but noticeably enhanced for the ( 100 ) surface. hydrogen segregation to surface layer vacancies is accompanied with minimal charge transfer, which shows itself in cluster configurations. at high surface coverage the reduction of the cluster formation energy due to the h segregation should result in strongly enlarged concentration of the subsurface vacancy clusters, while the surface remains undamaged due to the prevailing surface adsorption. | arxiv:2005.00623 |
strong external difference families ( sedfs ) were introduced by paterson and stinson as a more restrictive version of external difference families. sedfs can be used to produce optimal strong algebraic manipulation detection codes. we characterize the parameters $ ( v, m, k, \ lambda ) $ of a nontrivial sedf that is near - complete ( satisfying $ v = km + 1 $ ). we construct the first known nontrivial example of a $ ( v, m, k, \ lambda ) $ sedf having $ m > 2 $. the parameters of this example are $ ( 243, 11, 22, 20 ) $, giving a near - complete sedf, and its group is $ \ mathbb { z } _ 3 ^ 5 $. we provide a comprehensive framework for the study of sedfs using character theory and algebraic number theory, showing that the cases $ m = 2 $ and $ m > 2 $ are fundamentally different. we prove a range of nonexistence results, greatly narrowing the scope of possible parameters of sedfs. | arxiv:1701.05705 |
specific solutions of the nonlinear schr \ " odinger equation, such as the peregrine breather, are considered to be prototypes of extreme or freak waves in the oceans. an important question is, whether these solutions also exist in the presence of gusty wind. using the method of multiple scales, a nonlinear schr \ " odinger equation is obtained for the case of wind forced weakly nonlinear deep water waves. thereby, the wind forcing is modeled as a stochastic process. this leads to a stochastic nonlinear schr \ " odinger equation, which is calculated for different wind regimes. for the case of wind forcing which is either random in time or random in space, it is shown that breather type solutions such as the peregrine breather occur even in strong gusty wind conditions. | arxiv:1909.11761 |
in this work, we present quicksrnet, an efficient super - resolution architecture for real - time applications on mobile platforms. super - resolution clarifies, sharpens, and upscales an image to higher resolution. applications such as gaming and video playback along with the ever - improving display capabilities of tvs, smartphones, and vr headsets are driving the need for efficient upscaling solutions. while existing deep learning - based super - resolution approaches achieve impressive results in terms of visual quality, enabling real - time dl - based super - resolution on mobile devices with compute, thermal, and power constraints is challenging. to address these challenges, we propose quicksrnet, a simple yet effective architecture that provides better accuracy - to - latency trade - offs than existing neural architectures for single - image super resolution. we present training tricks to speed up existing residual - based super - resolution architectures while maintaining robustness to quantization. our proposed architecture produces 1080p outputs via 2x upscaling in 2. 2 ms on a modern smartphone, making it ideal for high - fps real - time applications. | arxiv:2303.04336 |
traffic steering is a crucial technology for wireless networks, and multiple efforts have been put into developing efficient machine learning ( ml ) - enabled traffic steering schemes for open radio access networks ( o - ran ). given the swift emergence of novel ml techniques, conducting a timely survey that comprehensively examines the ml - based traffic steering schemes in o - ran is critical. in this article, we provide such a survey along with a case study of hierarchical learning - enabled traffic steering in o - ran. in particular, we first introduce the background of traffic steering in o - ran and overview relevant state - of - the - art ml techniques and their applications. then, we analyze the compatibility of the hierarchical learning framework in o - ran and further propose a hierarchical deep - q - learning ( h - dqn ) framework for traffic steering. compared to existing works, which focus on single - layer architecture with standalone agents, h - dqn decomposes the traffic steering problem into a bi - level architecture with hierarchical intelligence. the meta - controller makes long - term and high - level policies, while the controller executes instant traffic steering actions under high - level policies. finally, the case study shows that the hierarchical learning approach can provide significant performance improvements over the baseline algorithms. | arxiv:2409.20391 |
in superstring theory spin structures are present on both the 2 - dimensional worldsheet and 10 - dimensional spacetime. we present a new proposal for the b - field in superstring theory and demonstrate its interaction with worldsheet spin structures. our formulation generalizes to orientifolds, where various twistings appear. a special case of the orientifold worldsheet b - field amplitude is a ko - theoretic construction of the z / 8z - valued kervaire invariant on pin - minus surfaces. | arxiv:1007.4581 |
we introduce a new language representation model called bert, which stands for bidirectional encoder representations from transformers. unlike recent language representation models, bert is designed to pre - train deep bidirectional representations from unlabeled text by jointly conditioning on both left and right context in all layers. as a result, the pre - trained bert model can be fine - tuned with just one additional output layer to create state - of - the - art models for a wide range of tasks, such as question answering and language inference, without substantial task - specific architecture modifications. bert is conceptually simple and empirically powerful. it obtains new state - of - the - art results on eleven natural language processing tasks, including pushing the glue score to 80. 5 % ( 7. 7 % point absolute improvement ), multinli accuracy to 86. 7 % ( 4. 6 % absolute improvement ), squad v1. 1 question answering test f1 to 93. 2 ( 1. 5 point absolute improvement ) and squad v2. 0 test f1 to 83. 1 ( 5. 1 point absolute improvement ). | arxiv:1810.04805 |
we analyze a class of topological static spherically symmetric vacuum solutions in $ f ( q ) $ - gravity. we considered an ansatz ensuring that those solutions trivially satisfy the field equations of the theory when the non - metricity scalar is constant. in the specific, we provide and discuss local solutions in the form of black holes and traversable wormholes. | arxiv:2208.13033 |
simulation of continuous time evolution requires time discretization on both classical and quantum computers. a finer time step improves simulation precision, but it inevitably leads to increased computational efforts. this is particularly costly for today ' s noisy intermediate scale quantum computers, where notable gate imperfections limit the circuit depth that can be executed at a given accuracy. classical adaptive solvers are well - developed to save numerical computation times. however, it remains an outstanding challenge to make optimal usage of the available quantum resources by means of adaptive time steps. here, we introduce a quantum algorithm to solve this problem, providing a controlled solution of the quantum many - body dynamics of local observables. the key conceptual element of our algorithm is a feedback loop which self - corrects the simulation errors by adapting time steps, thereby significantly outperforming conventional trotter schemes on a fundamental level and reducing the circuit depth. it even allows for a controlled asymptotic long - time error, where usual trotterized dynamics is facing difficulties. another key advantage of our quantum algorithm is that any desired conservation law can be included in the self - correcting feedback loop, which has potentially a wide range of applicability. we demonstrate the capabilities by enforcing gauge invariance which is crucial for a faithful and long - sought quantum simulation of lattice gauge theories. our algorithm can be potentially useful on a more general level whenever time discretization is involved concerning, for instance, also numerical approaches based on time - evolving block decimation methods. | arxiv:2209.12653 |
we summarize the current status of cosmological measurements using sne ia. searches to an average depth of z ~ 0. 5 have found approximately 100 sne ia to date, and measurements of their light curves and peak magnitudes find these objects to be about 0. 25mag fainter than predictions for an empty universe. these measurements imply low values for omega _ m and a positive cosmological constant, with high statistical significance. searches out to z ~ 1. 0 - 1. 2 for sne ia ( peak magnitudes of i ~ 24. 5 ) will greatly aid in confirming this result, or demonstrate the existence of systematic errors. multi - epoch spectra of sne ia at z ~ 0. 5 are needed to constrain possible evolutionary effects. i band searches should be able to find sne ia out to z ~ 2. we discuss some simulations of deep searches and discovery statistics at several redshifts. | arxiv:astro-ph/9909088 |
a new semi - empirical formula for calculations of $ \ alpha $ ~ decay halflives is presented. it was derived from royer relationship by introducing new parameters which are fixed by fit to a set of experimental data. we are using three sets : set a with 130 e - e ( even - even ), 119 e - o ( even - odd ), 109 o - e, and 96 o - o, set b with 188 e - e, 147 e - o, 131 o - e, and 114 o - o, and set c with 136 e - e, 84 e - o, 76 o - e, and 48 o - o alpha emitters. a comparison of results obtained with the new formula and the following well known relationships : semfis ( semiempirical based on fission theory ), asaf ( analytical superasymmetric fission ) model, and univ ( universal formula ) is made in terms of rms standard deviation. we also introduced a weighted mean value of this quantity, allowing to compare the global properties of a given model. for the set b the order of the four models is the following : semfis, univ, newf, and asaf. nevertheless for even - even alpha emitters univ gives the 2nd best result after semfis, and for odd - even parents the 2nd is newf. despite its simplicity in comparison with semfis the new formula, presented in this article, behaves quite well, competing with the others well known relationships. | arxiv:1702.05598 |
the \ textit { local learning coefficient } ( llc ) is a principled way of quantifying model complexity, originally derived in the context of bayesian statistics using singular learning theory ( slt ). several methods are known for numerically estimating the local learning coefficient, but so far these methods have not been extended to the scale of modern deep learning architectures or data sets. using a method developed in { \ tt arxiv : 2308. 12108 [ stat. ml ] } we empirically show how the llc may be measured accurately and self - consistently for deep linear networks ( dlns ) up to 100m parameters. we also show that the estimated llc has the rescaling invariance that holds for the theoretical quantity. | arxiv:2402.03698 |
the theory of physical dimensions and units in physics is outlined. this includes a discussion of the universal applicability and superiority of quantity equations. the international system of units ( si ) is one example thereof. by analyzing mechanics and electrodynamics, we are naturally led, besides the dimensions of length and time, to the fundamental units of action $ \ mathfrak h $, electric charge $ q $, and magnetic flux $ \ phi $. we have $ q \ times \ phi = \ text { action } $ and $ q / \ phi = 1 / \ text { resistance } $. these results of \ emph { classical physics } suggests to look into the corresponding quantum aspects of $ q $ and $ \ phi $ ( and also of $ \ mathfrak h $ ) : the electric charge occurs exclusively in elementary charges $ e $, whereas the magnetic flux can have any value ; in specific situations, however, in superconductors of type ii at very low temperatures, $ \ phi $ appears quantized in the form of fluxons ( abrikosov vortices ). and $ \ mathfrak { h } $ leads, of course, to the planck quantum $ h $. thus, we are directed to superconductivity and, because of the resistance, to the quantum hall effect. in this way, the josephson and the quantum hall effects come into focus quite naturally. one goal is to determine the behavior of the fundamental constants in special and in general relativity, that is, if gravity is thought to be switched off versus the case in the gravitational field. | arxiv:1810.03569 |
context. rr lyrae stars are useful standard candles allowing one to derive accurate distances for old star clusters. based on the recent catalogues from ogle - iv and gaia early data release 3 ( edr3 ), the distances can be improved for a few bulge globular clusters. aims. the aim of this work is to derive an accurate distance for the following six moderately metal - poor, relatively high - reddening bulge globular clusters : ngc 6266, ngc 6441, ngc 6626, ngc 6638, ngc 6642, and ngc 6717. methods. we combined newly available ogle - iv catalogues of variable stars containing mean i magnitudes, with clement ' s previous catalogues containing mean v magnitudes, and with precise proper motions from gaia edr3. astrometric membership probabilities were computed for each rr lyrae, in order to select those compatible with the cluster proper motions. applying luminosity - metallicity relations derived from basti $ \ alpha $ - enhanced models ( he - enhanced for ngc 6441 and canonical he for the other clusters ), we updated the distances with relatively low uncertainties. results. distances were derived with the i and v bands, with a $ 5 - 8 \ % $ precision. we obtained 6. 6 kpc, 13. 1 kpc, 5. 6 kpc, 9. 6 kpc, 8. 2 kpc, and 7. 3 kpc for ngc 6266, ngc 6441, ngc 6626, ngc 6638, ngc 6642, and ngc 6717, respectively. the results are in excellent agreement with the literature for all sample clusters, considering the uncertainties. conclusions. the present method of distance derivation, based on recent data of member rr lyrae stars, updated basti models, and robust statistical methods, proved to be consistent. a larger sample of clusters will be investigated in a future work. | arxiv:2110.13943 |
community detection approaches resolve complex networks into smaller groups ( communities ) that are expected to be relatively edge - dense and well - connected. the stochastic block model ( sbm ) is one of several approaches used to uncover community structure in graphs. in this study, we demonstrate that sbm software applied to various real - world and synthetic networks produces poorly - connected to disconnected clusters. we present simple modifications to improve the connectivity of sbm clusters, and show that the modifications improve accuracy using simulated networks. | arxiv:2408.10464 |
measure theory is used in physics, not just to capture classical probability, but also to quantify the number of states. in previous works, we found that state quantification plays a foundational role in classical mechanics, and therefore, we set ourselves to construct the quantum equivalent of the liouville measure. unlike the classical counterpart, this quantized measure is non - additive and has a unitary lower bound ( i. e. no set of states can have less than one state ). conversely, requiring that state quantification is finite for finite continuous regions and that each state counts as one already implies non - additivity, which in turn implies the failure of classical theory. in this article we show these preliminary results and outline a new line of inquiry that may provide a different insight into the foundations of quantum theory. additionally, this new approach may prove to be useful to those interested in a quantized theory of space - time, as we believe this requires a quantized measure for the quantification of the independent degrees of freedom. | arxiv:2311.01951 |
we develop the non - perturbative reduced phase space quantization of causal diamonds in ( 2 + 1 ) - dimensional gravity with a nonpositive cosmological constant. in this part i we focus on the classical reduction process, and the description of the reduced phase space, while in part ii we discuss the quantization of the phase space and quantum aspects of the causal diamonds. the system is defined as the domain of dependence of a spacelike topological disk with fixed boundary metric. by solving the constraints in a constant - mean - curvature time gauge and removing all the spatial gauge redundancy, we find that the phase space is the cotangent bundle of diff ^ + ( s ^ 1 ) / psl ( 2, r ), i. e., the group of orientation - preserving diffeomorphisms of the circle modulo the projective special linear subgroup. classically, the states correspond to causal diamonds embedded in ads _ 3 ( or mink _ 3 if $ \ lambda = 0 $ ), with fixed corner length, and whose cauchy surfaces have the topology of a disc. | arxiv:2308.11741 |
we have identified several lithium - rich low - mass ( 0. 08 < m < 0. 3 msun ) stars within 5. 5 deg of the young open cluster eta chamaeleontis, nearly four times the radius of previous search efforts. of these stars we propose 4 new probable cluster members, and 3 possible members requiring further investigation. these findings are consistent with a dynamical origin for the current configuration of the cluster, without the need to invoke an abnormal initial mass function deficient in low - mass objects. candidates were selected on the basis of denis and 2mass photometry, nomad astrometry and extensive follow - up spectroscopy. | arxiv:1005.3308 |
despite recent advances in mooc, the current e - learning systems have advantages of alleviating barriers by time differences, and geographically spatial separation between teachers and students. however, there has been a ' lack of supervision ' problem that e - learner ' s learning unit state ( lus ) can ' t be supervised automatically. in this paper, we present a fusion framework considering three channel data sources : 1 ) videos / images from a camera, 2 ) eye movement information tracked by a low solution eye tracker and 3 ) mouse movement. based on these data modalities, we propose a novel approach of multi - channel data fusion to explore the learning unit state recognition. we also propose a method to build a learning state recognition model to avoid manually labeling image data. the experiments were carried on our designed online learning prototype system, and we choose cart, random forest and gbdt regression model to predict e - learner ' s learning state. the results show that multi - channel data fusion model have a better recognition performance in comparison with single channel model. in addition, a best recognition performance can be reached when image, eye movement and mouse movement features are fused. | arxiv:1806.07372 |
the study of exploration in the domain of decision making has a long history but remains actively debated. from the vast literature that addressed this topic for decades under various points of view ( e. g., developmental psychology, experimental design, artificial intelligence ), intrinsic motivation emerged as a concept that can practically be transferred to artificial agents. especially, in the recent field of deep reinforcement learning ( rl ), agents implement such a concept ( mainly using a novelty argument ) in the shape of an exploration bonus, added to the task reward, that encourages visiting the whole environment. this approach is supported by the large amount of theory on rl for which convergence to optimality assumes exhaustive exploration. yet, human beings and mammals do not exhaustively explore the world and their motivation is not only based on novelty but also on various other factors ( e. g., curiosity, fun, style, pleasure, safety, competition, etc. ). they optimize for life - long learning and train to learn transferable skills in playgrounds without obvious goals. they also apply innate or learned priors to save time and stay safe. for these reasons, we propose to learn an exploration bonus from demonstrations that could transfer these motivations to an artificial agent with little assumptions about their rationale. using an inverse rl approach, we show that complex exploration behaviors, reflecting different motivations, can be learnt and efficiently used by rl agents to solve tasks for which exhaustive exploration is prohibitive. | arxiv:2006.12917 |
the cavity approach is used to address the physical properties of random solids in equilibrium. particular attention is paid to the fraction of localized particles and the distribution of localization lengths characterizing their thermal motion. this approach is of relevance to a wide class of random solids, including rubbery media ( formed via the vulcanization of polymer fluids ) and chemical gels ( formed by the random covalent bonding of fluids of atoms or small molecules ). the cavity approach confirms results that have been obtained previously via replica mean - field theory, doing so in a way that sheds new light on their physical origin. | arxiv:cond-mat/0506194 |
unimodular gravity is characterized by an extra condition with respect to general relativity : the determinant of the metric is constant. this extra condition leads to a more restricted class of invariance by coordinate transformation. even though, if the conservation of the energy - momentum tensor is imposed in unimodular gravity, the general relativity theory is recovered with an additional integration constant which is associated to the cosmological term $ \ lambda $. however, if the energy - momentum tensor does not conserve separately, a new geometric structure appears with potentially observational signatures. in this text, we consider the evolution of gravitational waves in the nonconservative unimodular gravity, showing how it differs from the usual signatures in the standard model. | arxiv:2112.06663 |
event cameras have recently been shown beneficial for practical vision tasks, such as action recognition, thanks to their high temporal resolution, power efficiency, and reduced privacy concerns. however, current research is hindered by 1 ) the difficulty in processing events because of their prolonged duration and dynamic actions with complex and ambiguous semantics and 2 ) the redundant action depiction of the event frame representation with fixed stacks. we find language naturally conveys abundant semantic information, rendering it stunningly superior in reducing semantic uncertainty. in light of this, we propose exact, a novel approach that, for the first time, tackles event - based action recognition from a cross - modal conceptualizing perspective. our exact brings two technical contributions. firstly, we propose an adaptive fine - grained event ( afe ) representation to adaptively filter out the repeated events for the stationary objects while preserving dynamic ones. this subtly enhances the performance of exact without extra computational cost. then, we propose a conceptual reasoning - based uncertainty estimation module, which simulates the recognition process to enrich the semantic representation. in particular, conceptual reasoning builds the temporal relation based on the action semantics, and uncertainty estimation tackles the semantic uncertainty of actions based on the distributional representation. experiments show that our exact achieves superior recognition accuracy of 94. 83 % ( + 2. 23 % ), 90. 10 % ( + 37. 47 % ) and 67. 24 % on paf, hardvs and our seact datasets respectively. | arxiv:2403.12534 |
the resonance x ( 1810 ) discovered in $ j / \ psi \ to \ gamma \ omega \ phi $ by besii is considered as a candidate of $ 0 ^ { + + } $ $ q ^ 2 \ bar { q } ^ 2 $ state. this model predicts that $ x \ to \ omega \ phi, k ^ * k ^ * $ are the two dominant decay channels and $ x \ to kk, \ eta \ eta, \ eta \ eta ' $ are suppressed. the cross sections of $ \ gamma \ gamma \ to x \ to \ omega \ phi, k ^ * k ^ * $ are estimated. | arxiv:hep-ph/0602072 |
this paper presents an approach combining lexico - semantic resources and distributed representations of words applied to the evaluation in machine translation ( mt ). this study is made through the enrichment of a well - known mt evaluation metric : meteor. this metric enables an approximate match ( synonymy or morphological similarity ) between an automatic and a reference translation. our experiments are made in the framework of the metrics task of wmt 2014. we show that distributed representations are a good alternative to lexico - semantic resources for mt evaluation and they can even bring interesting additional information. the augmented versions of meteor, using vector representations, are made available on our github page. | arxiv:1610.01291 |
we derive the evolution of the energy deposition in the intergalactic medium ( igm ) by dark matter ( dm ) decays / annihilations for both sterile neutrinos and light dark matter ( ldm ) particles. at z > 200 sterile neutrinos transfer a fraction f _ abs ~ 0. 5 of their rest mass energy into the igm ; at lower redshifts this fraction becomes < ~ 0. 3 depending on the particle mass. the ldm particles can decay or annihilate. in both cases f _ abs ~ 0. 4 - 0. 9 at high ( > 300 ) redshift, dropping to ~ 0. 1 below z = 100. these results indicate that the impact of dm decays / annihilations on the igm thermal and ionization history is less important than previously thought. we find that sterile neutrinos ( ldm ) decays are able to increase the igm temperature by z = 5 at most up to 4k ( 100k ), about 50 - 200 times less than predicted by estimates based on the assumption of complete energy transfer to the gas. | arxiv:astro-ph/0606482 |
it is proved that solutions of the complex monge - amp \ ` ere equation on compact k \ " ahler manifolds with right hand side in $ l ^ p, p > 1 $ are uniformly h \ " older continuous under the assumption on non - negative orthogonal bisectional curvature. | arxiv:0904.2578 |
in negatively curved field spaces, inflation can be realised even in steep potentials. hyperinflation invokes the ` centrifugal force ' of a field orbiting the hyperbolic plane to sustain inflation. we generalise hyperinflation by showing that it can be realised in models with any number of fields ( $ n _ f \ geq2 $ ), and in broad classes of potentials that, in particular, don ' t need to be rotationally symmetric. for example, hyperinflation can follow a period of radial slow - roll inflation that undergoes geometric destabilisation, yet this inflationary phase is not identical to the recently proposed scenario of ` side - tracked inflation '. we furthermore provide a detailed proof of the attractor mechanism of ( the original and generalised ) hyperinflation, and provide a novel set of characteristic, explicit models. we close by discussing the compatibility of hyperinflation with observations and the recently much discussed ` swampland conjectures '. observationally viable models can be realised that satisfy either the ` de sitter conjecture ' ( $ v ' / v \ gtrsim 1 $ ) or the ` distance conjecture ' ( $ \ delta \ phi \ lesssim 1 $ ), but satisfying both simultaneously brings hyperinflation in some tension with successful reheating after inflation. however, hyperinflation can get much closer to satisfying all of these criteria than standard slow - roll inflation. furthermore, while the original model is in stark tension with the weak gravity conjecture, generalisations can circumvent this issue. | arxiv:1901.08603 |
to understand the interplay of d - wave superconductivity and antiferromagnetism, we consider a two - dimensional extended hubbard model with nearest neighbor attractive interaction. the hamiltonian is solved in the mean - field approximation on a finite lattice. in the impurity - free case, the minimum energy solutions show phase separation as predicted previously based on free energy argument. the phase separation tendency implies that the system can be easily rendered inhomogeneous by a small external perturbation. explicit solutions of a model including weak impurity potentials are indeed inhomogeneous in the spin - density - wave and d - wave pairing order parameters. relevance of the results to the inhomogeneous cuprate superconductors is discussed. | arxiv:cond-mat/0604400 |
we derive mathematical models of the elementary process of dissolution / growth of bubbles in a liquid under pressure control. the modeling starts with a fully compressible version, both for the liquid and the gas phase so that the entropy principle can be easily evaluated. this yields a full pde system for a compressible two - phase fluid with mass transfer of the gaseous species. then the passage to an incompressible solvent in the liquid phase is discussed, where a carefully chosen equation of state for the liquid mixture pressure allows for a limit in which the solvent density is constant. we finally provide a simplification of the pde system in case of a dilute solution. | arxiv:1403.0248 |
we present a five - band herschel study ( 100 - 500um ) of three galaxy clusters at z ~ 1. 2 from the spitzer adaptation of the red - sequence cluster survey ( sparcs ). with a sample of 120 spectroscopically - confirmed cluster members, we investigate the role of environment on galaxy properties utilizing the projected cluster phase space ( line - of - sight velocity versus clustercentric radius ), which probes the time - averaged galaxy density to which a galaxy has been exposed. we divide cluster galaxies into phase - space bins of ( r / r200 ) x ( v / sigma _ v ), tracing a sequence of accretion histories in phase space. stacking optically star - forming cluster members on the herschel maps, we measure average infrared star formation rates, and, for the first time in high - redshift galaxy clusters, dust temperatures for dynamically distinct galaxy populations - - - namely, recent infalls and those that were accreted onto the cluster at an earlier epoch. proceeding from the infalling to virialized ( central ) regions of phase space, we find a steady decrease in the specific star formation rate and increase in the stellar age of star - forming cluster galaxies. we perform a probability analysis to investigate all acceptable infrared spectral energy distributions within the full parameter space and measure a ~ 4 sigma drop in the average dust temperature of cluster galaxies in an intermediate phase - space bin, compared to an otherwise flat trend with phase space. we suggest one plausible quenching mechanism which may be consistent with these trends, invoking ram - pressure stripping of the warmer dust for galaxies within this intermediate accretion phase. | arxiv:1511.00584 |
we measured the microwave surface impedance of fese $ _ { 0. 4 } $ te $ _ { 0. 6 } $ single crystals with - and without external magnetic fields. the superfluid density exhibited a quadratic temperature dependence, indicating a strong pair - breaking effect. the flux - flow resistivity behaved as $ \ rho _ f ( b \ ll b _ { \ rm c2 } ) / \ rho _ n = \ alpha b / b _ { \ rm c2 } $. the observed $ \ alpha $ value of $ \ approx0. 66 $ was considerably smaller than that of other fe - based materials ( $ \ alpha \ geq1 $ ) and was attributed to a back - flow of superfluids remarkable in disordered superconductors. this is the first - time observation of the back - flow phenomenon caused by an origin other than the vortex pinning in multiple - band systems. | arxiv:1406.7383 |
when a projection of a symmetric or hermitian matrix to the positive semidefinite cone is computed approximately ( or to working precision on a computer ), a natural question is to quantify its accuracy. a straightforward bound invoking standard eigenvalue perturbation theory ( e. g. davis - kahan and weyl bounds ) suggests that the accuracy would be inversely proportional to the spectral gap, implying it can be poor in the presence of small eigenvalues. this work shows that a small gap is not a concern for projection onto the semidefinite cone, by deriving error bounds that are gap - independent. | arxiv:1908.01606 |
student opinions for a course are important to educators and administrators, regardless of the type of the course or the institution. reading and manually analyzing open - ended feedback becomes infeasible for massive volumes of comments at institution level or online forums. in this paper, we collected and pre - processed a large number of course reviews publicly available online. we applied machine learning techniques with the goal to gain insight into student sentiments and topics. specifically, we utilized current natural language processing ( nlp ) techniques, such as word embeddings and deep neural networks, and state - of - the - art bert ( bidirectional encoder representations from transformers ), roberta ( robustly optimized bert approach ) and xlnet ( generalized auto - regression pre - training ). we performed extensive experimentation to compare these techniques versus traditional approaches. this comparative study demonstrates how to apply modern machine learning approaches for sentiment polarity extraction and topic - based classification utilizing course feedback. for sentiment polarity, the top model was roberta with 95. 5 % accuracy and 84. 7 % f1 - macro, while for topic classification, an svm ( support vector machine ) was the top classifier with 79. 8 % accuracy and 80. 6 % f1 - macro. we also provided an in - depth exploration of the effect of certain hyperparameters on the model performance and discussed our observations. these findings can be used by institutions and course providers as a guide for analyzing their own course feedback using nlp models towards self - evaluation and improvement. | arxiv:2304.03394 |
in the present work, we study the decompositions of codimension - one transitions that alter the singular set the of stable maps of $ s ^ 3 $ into $ \ mathbb { r } ^ 3, $ the topological behaviour of the singular set and the singularities in the branch set that involves cuspidal curves and swallowtails that alter the singular set. we also analyse the effects of these decompositions on the global invariants with prescribed branch sets. | arxiv:1807.06122 |
we classify certain $ \ mathbb { z } _ 2 $ - graded extensions of generalized haagerup categories in terms of numerical invariants satisfying polynomial equations. in particular, we construct a number of new examples of fusion categories, including : $ \ mathbb { z } _ 2 $ - graded extensions of $ \ mathbb { z } _ { 2n } $ generalized haagerup categories for all $ n \ leq 5 $ ; $ \ mathbb { z } _ 2 \ times \ mathbb { z } _ 2 $ - graded extensions of the asaeda - haagerup categories ; and extensions of the $ \ mathbb { z } _ 2 \ times \ mathbb { z } _ 2 $ generalized haagerup category by its outer automorphism group $ a _ 4 $. the construction uses endomorphism categories of operator algebras, and in particular, free products of cuntz algebras with free group c $ ^ * $ - algebras. | arxiv:2201.11901 |
data from four fermi - detected gamma - ray bursts ( grbs ) is used to set limits on spectral dispersion of electromagnetic radiation across the universe. the analysis focuses on photons recorded above 1 gev for fermi detected grb 080916c, grb 090510a, grb 090902b, and grb 090926a because these high - energy photons yield the tightest bounds on light dispersion. it is shown that significant photon bunches in grb 090510a, possibly classic grb pulses, are remarkably brief, an order of magnitude shorter in duration than any previously claimed temporal feature in this energy range. although conceivably a $ > 3 \ sigma $ fluctuation, when taken at face value, these pulses lead to an order of magnitude tightening of prior limits on photon dispersion. bound of $ \ delta c / c < 6. 94 $ x $ 10 ^ { - 21 } $ is thus obtained. given generic dispersion relations where the time delay is proportional to the photon energy to the first or second power, the most stringent limits on the dispersion strengths were $ k _ 1 < $ 1. 61 x $ 10 ^ { - 5 } $ sec gpc $ ^ { - 1 } $ gev $ ^ { - 1 } $ and $ k _ 2 < $ 3. 57 x $ 10 ^ { - 7 } $ sec gpc $ ^ { - 1 } $ gev $ ^ { - 2 } $ respectively. such limits constrain dispersive effects created, for example, by the spacetime foam of quantum gravity. in the context of quantum gravity, our bounds set $ m _ 1 c ^ 2 $ greater than 525 times the planck mass, suggesting that spacetime is smooth at energies near and slightly above the planck mass. | arxiv:1109.5191 |
in integrable one - dimensional quantum systems an infinite set of local conserved quantities exists which can prevent a current from decaying completely. for cases like the spin current in the xxz model at zero magnetic field or the charge current in the attractive hubbard model at half filling, however, the current operator does not have overlap with any of the local conserved quantities. we show that in these situations transport at finite temperatures is dominated by a diffusive contribution with the drude weight being either small or even zero. for the xxz model we discuss in detail the relation between our results, the phenomenological theory of spin diffusion, and measurements of the spin - lattice relaxation rate in spin chain compounds. furthermore, we study the haldane - shastry model where the current operator is also orthogonal to the set of conserved quantities associated with integrability but becomes itself conserved in the thermodynamic limit. | arxiv:1011.1354 |
single - cavity dual - comb lasers are a new class of ultrafast lasers which have a wide possible application space including pump - probe sampling, optical ranging, and gas absorption spectroscopy. however, to this date laser cavity multiplexing usually came to the trade - off in laser performance or relative timing noise suppression. we present a new method for multiplexing a single laser cavity to support a pair of noise - correlated modes. these modes share all intracavity components and take a near - common path, but do not overlap on any active elements. we implement the method with an 80 - mhz laser delivering more than 2. 4 watts of average power per comb with sub - 140 fs pulses. we reach sub - cycle relative timing jitter of 2. 2 fs [ 20 hz, 100 khz ]. with this new multiplexing technique, we could implement slow feedback on the repetition rate difference { \ delta } frep, enabling this quantity to be drift - free, low - jitter, and adjustable - a key combination for practical applications that was lacking in prior single - cavity dual - comb systems. | arxiv:2203.08536 |
road transportation is one of the largest sectors of greenhouse gas ( ghg ) emissions affecting climate change. tackling climate change as a global community will require new capabilities to measure and inventory road transport emissions. however, the large scale and distributed nature of vehicle emissions make this sector especially challenging for existing inventory methods. in this work, we develop machine learning models that use satellite imagery to perform indirect top - down estimation of road transport emissions. our initial experiments focus on the united states, where a bottom - up inventory was available for training our models. we achieved a mean absolute error ( mae ) of 39. 5 kg co $ _ { 2 } $ of annual road transport emissions, calculated on a pixel - by - pixel ( 100 m $ ^ { 2 } $ ) basis in sentinel - 2 imagery. we also discuss key model assumptions and challenges that need to be addressed to develop models capable of generalizing to global geography. we believe this work is the first published approach for automated indirect top - down estimation of road transport sector emissions using visual imagery and represents a critical step towards scalable, global, near - real - time road transportation emissions inventories that are measured both independently and objectively. | arxiv:2103.08829 |
this paper deals with some nonlinear problems which exponential and biexponential decays are involved in. a proof of the quasiconvexity of the error function in some of these problems of optimization is presented. this proof is restricted to fitting observations by means of exponentials having the form $ f ( t ) = { \ lambda } _ 1 \ exp ( kt ) + { \ lambda } _ 2. $ based on its quasiconvexity, we propose an algorithm to estimate the best approximation to each of these decays. besides, this algorithm does not require an initial guess. | arxiv:1711.07891 |
an analysis is presented of the behaviour of muons in the low - temperature state in spin ice. it is shown in detail how the behavior observed in some previous muon experiments on spin ice in a weak transverse field may result from the macroscopic stray field of magnetized spin ice. a model is presented which allows these macroscopic field effects to be simulated and the results agree with experiment. the persistent spin dynamics at low temperature originate from the sample and could be a muon - induced implantation effect that is operative in out - of - equilibrium systems with long relaxation times. | arxiv:1111.3657 |
cosmological correlators encode rich information about physics at the hubble scale and may exhibit characteristic oscillatory signals due to the exchange of massive particles. although many 1 - loop processes, especially those that break de sitter ( ds ) boosts, can generate significant leading signals for various particle models in cosmological collider physics, the precise results for these correlators or their full signals remain unknown due to the lack of symmetry. in this work, we apply the method of partial mellin - barnes ( pmb ) representation to the calculation of cosmological correlators at the loop level. as a first step, we use the pmb representation to calculate four - point cosmological correlators with bubble topology. we find that both the nonlocal and local signals arise from the factorized part, validating the cutting rules proposed in previous work, and are free from uv divergence. furthermore, the uv divergence originates solely from the background piece and can be manifestly canceled by introducing the appropriate counterterm, similar to the procedure in flat spacetime. we also demonstrate how to renormalize the 1 - loop correlators in mellin space. after a consistency check with known results for the covariant case, we provide new analytical results for the signals generated from a nontrivial ds - boost - breaking bubble. | arxiv:2411.13636 |
we investigate the role of quantum fluctuations in the system composed of two branes bounding a region of ads. it is shown that the modulus effective potential generated by quantum fluctuations of both brane and bulk fields is incapable of stabilizing the space naturally at the separation needed to generate the hierarchy. consequently, a classical stabilization mechanism is required. we describe the proper method of regulating the loop integrals and show that, for large brane separation, the quantum effects are power suppressed and therefore have negligible affects on the bulk dynamics once a classical stabilization mechanism is in place. | arxiv:hep-th/0007065 |
onset of antiferromagnetism order in the $ \ sqrt { 5 } $ a $ \ times \ sqrt { 5 } $ a $ \ times $ c supercell decreases from 450k in the selenide ( x = 0 ) to 330k in the sulfide ( x = 1 ). we finally demonstrate a direct linear relationship between $ t _ { n \ acute { e } el } $ and the fe - ( se, s ) bond length ( or fe - ( se, s ) height ). | arxiv:1203.6181 |
the vacuum expectation values of the energy - - momentum tensor and the fermionic condensate are analyzed for a massive spinor field obeying the mit bag boundary condition on a cylindrical shell in the cosmic string spacetime. both regions inside and outside the shell are considered. by applying to the corresponding mode - sums a variant of the generalized abel - - plana formula, we explicitly extract the parts in the expectation values corresponding to the cosmic string geometry without boundaries. in this way the renormalization procedure is reduced to that for the boundary - free cosmic string spacetime. the parts induced by the cylindrical shell are presented in terms of integrals rapidly convergent for points away from the boundary. the behavior of the vacuum densities is investigated in various asymptotic regions of the parameters. in the limit of large values of the planar angle deficit, the boundary - induced expectation values are exponentially suppressed. as a special case, we discuss the fermionic vacuum densities for the cylindrical shell on the background of the minkowski spacetime. | arxiv:0809.0844 |
in designing most software applications, much effort is placed upon the functional goals, which make a software system useful. however, the failure to consider emotional goals, which make a software system pleasurable to use, can result in disappointment and system rejection even if utilitarian goals are well implemented. although several studies have emphasized the importance of people ' s emotional goals in developing software, there is little advice on how to address these goals in the software system development process. this paper proposes a theoretically - sound and practical method by combining the theories and techniques of software engineering, requirements engineering, and decision making. the outcome of this study is the emotional goal systematic analysis technique ( eg - sat ), which facilitates the process of finding software system capabilities to address emotional goals in software design. eg - sat is easy to learn and easy to use technique that helps analysts to gain insights into how to address people ' s emotional goals. to demonstrate the method in use, a two - part evaluation is conducted. first, eg - sat is used to analyze the emotional goals of potential users of a mobile learning application that provides information about low carbon living for tradespeople and professionals in the building industry in australia. the results of using eg - sat in this case study are compared with a professionally - developed baseline. second, we ran a semi - controlled experiment in which 12 participants were asked to apply eg - sat and another technique on part of our case study. the outcomes show that eg - sat helped participants to both analyse emotional goals and gain valuable insights about the functional and non - functional goals for addressing people ' s emotional goals. | arxiv:1810.12547 |
we present a data - driven and physics - informed algorithm for drilling accident forecasting. the core machine - learning algorithm uses the data from the drilling telemetry representing the time - series. we have developed a bag - of - features representation of the time series that enables the algorithm to predict the probabilities of six types of drilling accidents in real - time. the machine - learning model is trained on the 125 past drilling accidents from 100 different russian oil and gas wells. validation shows that the model can forecast 70 % of drilling accidents with a false positive rate equals to 40 %. the model addresses partial prevention of the drilling accidents at the well construction. | arxiv:2203.05378 |
in this paper we extend existing bayesian methods for variable selection in gaussian process regression, to select both the regression terms and the active covariates in the spatial correlation structure. we then use the estimated posterior probabilities to choose between relatively few modes through cross - validation, and consequently improve prediction. | arxiv:1501.00083 |
semantic segmentation is a key technology for autonomous vehicles to understand the surrounding scenes. the appealing performances of contemporary models usually come at the expense of heavy computations and lengthy inference time, which is intolerable for self - driving. using light - weight architectures ( encoder - decoder or two - pathway ) or reasoning on low - resolution images, recent methods realize very fast scene parsing, even running at more than 100 fps on a single 1080ti gpu. however, there is still a significant gap in performance between these real - time methods and the models based on dilation backbones. to tackle this problem, we proposed a family of efficient backbones specially designed for real - time semantic segmentation. the proposed deep dual - resolution networks ( ddrnets ) are composed of two deep branches between which multiple bilateral fusions are performed. additionally, we design a new contextual information extractor named deep aggregation pyramid pooling module ( dappm ) to enlarge effective receptive fields and fuse multi - scale context based on low - resolution feature maps. our method achieves a new state - of - the - art trade - off between accuracy and speed on both cityscapes and camvid dataset. in particular, on a single 2080ti gpu, ddrnet - 23 - slim yields 77. 4 % miou at 102 fps on cityscapes test set and 74. 7 % miou at 230 fps on camvid test set. with widely used test augmentation, our method is superior to most state - of - the - art models and requires much less computation. codes and trained models are available online. | arxiv:2101.06085 |
using the coherent state techniques developed for the analysis of the eprl model we give the asymptotic formula for the ponzano - regge model amplitude for non - tardis triangulations of handlebodies in the limit of large boundary spins. the formula produces a sum over all possible immersions of the boundary triangulation and its value is given by the cosine of the regge action evaluated on these. furthermore the asymptotic scaling registers the existence of flexible immersions. we verify numerically that this formula approximates the 6j - symbol for large spins. | arxiv:0909.2027 |
we study nonparametric estimation for the partially conditional average treatment effect, defined as the treatment effect function over an interested subset of confounders. we propose a hybrid kernel weighting estimator where the weights aim to control the balancing error of any function of the confounders from a reproducing kernel hilbert space after kernel smoothing over the subset of interested variables. in addition, we present an augmented version of our estimator which can incorporate estimations of outcome mean functions. based on the representer theorem, gradient - based algorithms can be applied for solving the corresponding infinite - dimensional optimization problem. asymptotic properties are studied without any smoothness assumptions for propensity score function or the need of data splitting, relaxing certain existing stringent assumptions. the numerical performance of the proposed estimator is demonstrated by a simulation study and an application to the effect of a mother ' s smoking on a baby ' s birth weight conditioned on the mother ' s age. | arxiv:2103.03437 |
as the use of deep learning techniques has grown across various fields over the past decade, complaints about the opaqueness of the black - box models have increased, resulting in an increased focus on transparency in deep learning models. this work investigates various methods to improve the interpretability of deep neural networks for natural language processing ( nlp ) tasks, including machine translation and sentiment analysis. we provide a comprehensive discussion on the definition of the term interpretability and its various aspects at the beginning of this work. the methods collected and summarised in this survey are only associated with local interpretation and are specifically divided into three categories : 1 ) interpreting the model ' s predictions through related input features ; 2 ) interpreting through natural language explanation ; 3 ) probing the hidden states of models and word representations. | arxiv:2103.11072 |
the dominant dimension of algebras in the class a of 1 - quasi - hereditary algebras is at least two. by the morita - tachikawa theorem this implies that a is related to a certain class b of algebras via bimodules satisfying the double centralizer condition. in this paper we specify the class b and the modules over algebras in b connected with a. the class a is not closed under taking the ringel - dual. however the dominant dimension of the ringel - dual r ( q ) of a 1 - quasi - hereditary algebra q is at least two. this fact induces a corresponding concept of modules over algebras in b which yield the algebras q and r ( q ) for q in a. | arxiv:1206.1786 |
a new type of nonlinear dust pulse structures has been observed in afterglow complex plasma under microgravity condition on board the international space station ( iss ). the dust pulses are triggered spontaneously as the plasma is switched off and the particles start to flow through each other ( uni - directional or counter - streaming ) in the presence of a low - frequency external electric excitation. the pulses are oblique with respect to the microparticle cloud and appear to be symmetric with respect to the central axis. a possible explanation of this observation with the spontaneous development of a double layer in the afterglow of complex plasma is described. | arxiv:2103.09607 |
energy theft, characterized by manipulating energy consumption readings to reduce payments, poses a dual threat - causing financial losses for grid operators and undermining the performance of smart grids. effective energy theft detection ( etd ) methods become crucial in mitigating these risks by identifying such fraudulent activities in their early stages. however, the majority of current etd methods rely on supervised learning, which is hindered by the difficulty of labelling data and the risk of overfitting known attacks. to address these challenges, several unsupervised etd methods have been proposed, focusing on learning the normal patterns from honest users, specifically the reconstruction of input. however, our investigation reveals a limitation in current unsupervised etd methods, as they can only detect anomalous behaviours in users exhibiting regular patterns. users with high - variance behaviours pose a challenge to these methods. in response, this paper introduces a denoising diffusion probabilistic model ( ddpm ) - based etd approach. this innovative approach demonstrates impressive etd performance on high - variance smart grid data by incorporating additional attributes correlated with energy consumption. the proposed methods improve the average etd performance on high - variance smart grid data from below 0. 5 to over 0. 9 w. r. t. auc. on the other hand, our experimental findings indicate that while the state - of - the - art etd methods based on reconstruction error can identify etd attacks for the majority of users, they prove ineffective in detecting attacks for certain users. to address this, we propose a novel ensemble approach that considers both reconstruction error and forecasting error, enhancing the robustness of the etd methodology. the proposed ensemble method improves the average etd performance on the stealthiest attacks from nearly 0 to 0. 5 w. r. t. 5 % - tpr. | arxiv:2307.16149 |
the optimal source - finding strategy for linear polarization data is an unsolved problem, with many inhibitive factors imposed by the technically - challenging nature of polarization observations. such an algorithm is essential for square kilometre array ( ska ) pathfinder surveys, such as the multifrequency snapshot sky survey ( msss ) with the low frequency array ( lofar ), as data volumes are significant enough to prohibit manual inspection. we present a new strategy of ` faraday moments ' for source - finding in linear polarization with lofar, using the moments of the frequency - dependent full - stokes data ( i. e. the mean, standard deviation, skewness, and excess kurtosis ). through simulations of the sky, we find that moments can identify polarized sources with a high completeness : 98. 5 % at a signal - to - noise of 5. while the method has low reliability, rotation measure ( rm ) synthesis can be applied per candidate source to filter out instrumental and spurious detections. this combined strategy will result in a complete and reliable catalogue of polarized sources that includes the full sensitivity of the observational bandwidth. we find that the technique can reduce the number of pixels on which rm synthesis needs to be performed by a factor of $ \ approx1 \ times10 ^ { 5 } $ for source distributions anticipated with modern radio telescopes. through tests on lofar data, we find that the technique works effectively in the presence of diffuse emission. extensions of this method are directly applicable to other upcoming radio surveys such as the polarization sky survey of the universe ' s magnetism ( possum ) with the australia square kilometre array pathfinder ( askap ), and the ska itself. | arxiv:1711.04516 |
we derive some entanglement properties of the ground states of two classes of quantum spin chains described by the fredkin model, for half - integer spins, and the motzkin model, for integer ones. since the ground states of the two models are known analytically, we can calculate the entanglement entropy, the negativity and the quantum mutual information exactly. we show, in particular, that these systems exhibit long - distance entanglement, namely two disjoint regions of the chains remain entangled even when the separation is sent to infinity, i. e. these systems are not affected by decoherence. this strongly entangled behavior, occurring both for colorful versions of the models ( with spin larger than 1 / 2 or 1, respectively ) and for colorless cases ( spin 1 / 2 and 1 ), is consistent with the violation of the cluster decomposition property. moreover we show that this behavior involves disjoint segments located both at the edges and in the bulk of the chains. | arxiv:1904.05205 |
state - of - the - art schemes for performance analysis and optimization of multiple - input multiple - output systems generally experience degradation or even become invalid in dynamic complex scenarios with unknown interference and channel state information ( csi ) uncertainty. to adapt to the challenging settings and better accomplish these network auto - tuning tasks, we propose a generic learnable model - driven framework in this paper. to explain how the proposed framework works, we consider regularized zero - forcing precoding as a usage instance and design a light - weight neural network for refined prediction of sum rate and detection error based on coarse model - driven approximations. then, we estimate the csi uncertainty on the learned predictor in an iterative manner and, on this basis, optimize the transmit regularization term and subsequent receive power scaling factors. a deep unfolded projected gradient descent based algorithm is proposed for power scaling, which achieves favorable trade - off between convergence rate and robustness. | arxiv:2206.15072 |
we consider a spherically symmetric and asymptotically flat vacuum solution of the horava - lifshitz ( hl ) gravity that is the analog of the general relativistic schwarzschild black hole. in the weak - field and slow - motion approximation, we work out the correction to the third kepler law of a test particle induced by such a solution and compare it to the phenomenologically determined orbital period of the transiting extrasolar planet hd209458b osiris to preliminarily obtain an order - of - magnitude lower bound on the ks dimensionless parameter \ omega _ 0 > = 1. 4 \ times 10 ^ - 18. as suggestions for further analyses, the entire data set of hd209458b should be re - processed by explicitly modeling ks gravity as well, and one or more dedicated solve - for parameter ( s ) should be estimated. | arxiv:0909.5355 |
this paper presents a dual - stream text - to - speech ( tts ) model, syncspeech, capable of receiving streaming text input from upstream models while simultaneously generating streaming speech, facilitating seamless interaction with large language models. syncspeech has the following advantages : low latency, as it begins generating streaming speech upon receiving the second text token ; high efficiency, as it decodes all speech tokens corresponding to the each arrived text token in one step. to achieve this, we propose a temporal masked transformer as the backbone of syncspeech, combined with token - level duration prediction to predict speech tokens and the duration for the next step. additionally, we design a two - stage training strategy to improve training efficiency and the quality of generated speech. we evaluated the syncspeech on both english and mandarin datasets. compared to the recent dual - stream tts models, syncspeech significantly reduces the first packet delay of speech tokens and accelerates the real - time factor. moreover, with the same data scale, syncspeech achieves performance comparable to that of traditional autoregressive - based tts models in terms of both speech quality and robustness. speech samples are available at https : / / syncspeech. github. io / } { https : / / syncspeech. github. io /. | arxiv:2502.11094 |
we present recent studies using the near - infrared instrument amber of the vlt interferometer ( vlti ) to investigate the structure and shaping processes within the extended atmosphere of agb stars. spectrally resolved near - infrared amber observations of the mira variable s ori have revealed wavelength - dependent apparent angular sizes. these data were successfully compared to dynamic model atmospheres, which predict wavelength - dependent radii because of geometrically extended molecular layers. most recently, amber closure phase measurements of several agb stars have also revealed wavelength - dependent deviations from 0 / 180 deg., indicating deviations from point symmetry. the variation of closure phase with wavelength indicates a complex non - spherical stratification of the extended atmosphere, and may reveal whether observed asymmetries are located near the photosphere or in the outer molecular layers. concurrent observations of sio masers located within the extended molecular layers provide us with additional information on the morphology, conditions, and kinematics of this shell. these observations promise to provide us with new important insights into the shaping processes at work during the agb phase. with improved imaging capabilities at the vlti, we expect to extend the successful story of imaging studies of planetary nebulae to the photosphere and extended outer atmosphere of agb stars. | arxiv:1105.3392 |
we develop an algorithm based on an interaction network to identify high - transverse - momentum higgs bosons decaying to bottom quark - antiquark pairs and distinguish them from ordinary jets that reflect the configurations of quarks and gluons at short distances. the algorithm ' s inputs are features of the reconstructed charged particles in a jet and the secondary vertices associated with them. describing the jet shower as a combination of particle - to - particle and particle - to - vertex interactions, the model is trained to learn a jet representation on which the classification problem is optimized. the algorithm is trained on simulated samples of realistic lhc collisions, released by the cms collaboration on the cern open data portal. the interaction network achieves a drastic improvement in the identification performance with respect to state - of - the - art algorithms. | arxiv:1909.12285 |
we consider the entropic regularization of discretized optimal transport and propose to solve its optimality conditions via a logarithmic newton iteration. we show a quadratic convergence rate and validate numerically that the method compares favorably with the more commonly used sinkhorn - - knopp algorithm for small regularization strength. we further investigate numerically the robustness of the proposed method with respect to parameters such as the mesh size of the discretization. | arxiv:1710.06635 |
it is now well understood that machine learning models, trained on data without due care, often exhibit unfair and discriminatory behavior against certain populations. traditional algorithmic fairness research has mainly focused on supervised learning tasks, particularly classification. while fairness in unsupervised learning has received some attention, the literature has primarily addressed fair representation learning of continuous embeddings. in this paper, we conversely focus on unsupervised learning using probabilistic graphical models with discrete latent variables. we develop a fair stochastic variational inference technique for the discrete latent variables, which is accomplished by including a fairness penalty on the variational distribution that aims to respect the principles of intersectionality, a critical lens on fairness from the legal, social science, and humanities literature, and then optimizing the variational parameters under this penalty. we first show the utility of our method in improving equity and fairness for clustering using na \ " ive bayes and gaussian mixture models on benchmark datasets. to demonstrate the generality of our approach and its potential for real - world impact, we then develop a special - purpose graphical model for criminal justice risk assessments, and use our fairness approach to prevent the inferences from encoding unfair societal biases. | arxiv:2209.07044 |
network science is a powerful tool for analyzing complex systems in fields ranging from sociology to engineering to biology. this paper is focused on generative models of large - scale bipartite graphs, also known as two - way graphs or two - mode networks. we propose two generative models that can be easily tuned to reproduce the characteristics of real - world networks, not just qualitatively, but quantitatively. the characteristics we consider are the degree distributions and the metamorphosis coefficient. the metamorphosis coefficient, a bipartite analogue of the clustering coefficient, is the proportion of length - three paths that participate in length - four cycles. having a high metamorphosis coefficient is a necessary condition for close - knit community structure. we define edge, node, and degreewise metamorphosis coefficients, enabling a more detailed understanding of the bipartite connectivity that is not explained by degree distribution alone. our first model, bipartite chung - lu ( cl ), is able to reproduce real - world degree distributions, and our second model, bipartite block two - level erd \ " os - r \ ' enyi ( bter ), reproduces both the degree distributions as well as the degreewise metamorphosis coefficients. we demonstrate the effectiveness of these models on several real - world data sets. | arxiv:1607.08673 |
understanding and modeling pedestrian dynamics in dense crowds is a complex yet essential aspect of crowd management and urban planning. in this work, we investigate the dynamics of a dense crowd crossed by a cylindrical intruder using a mean - field game ( mfg ) model. by incorporating a discount factor to account for pedestrians ' limited anticipation and information processing, we examine the model ' s ability to simulate two distinct experimental configurations : pedestrians facing the obstacle and pedestrians giving their back to the intruder. through a comprehensive comparison with experimental data, we demonstrate that the mfg model effectively captures essential crowd behaviors, including anticipatory motion and collision avoidance. | arxiv:2403.01168 |
the network approach plays a distinguished role in contemporary science of complex systems / phenomena. such an approach has been introduced into seismology in a recent work [ s. abe and n. suzuki, europhys. lett. 65, 581 ( 2004 ) ]. here, we discuss the dynamical property of the earthquake network constructed in california and report the discovery that the values of the clustering coefficient remain stationary before main shocks, suddenly jump up at the main shocks, and then slowly decay following a power law to become stationary again. thus, the network approach is found to characterize main shocks in a peculiar manner. | arxiv:physics/0612058 |
the casimir force between two parallel plates separated by anisotropic media is investigated. we theoretically calculate the casimir force between two parallel plates when the interspace between the plates is filled with anisotropic media. our result shows that the anisotropy of the material between the plates can significantly affect the casimir force, especially the direction of the force. if ignoring the anisotropy of the in - between material makes the force to be repulsive ( attractive ), by contrast, taking the anisotropy into account may produce an extra attractive ( repulsive ) force. the physical explanation for this phenomenon is also discussed. | arxiv:1502.06335 |
we prove a base point free theorem for nef and log big divisors on log canonical surfaces. | arxiv:alg-geom/9705005 |
we present a quantitative investigation of the effect of stellar oscillations on doppler velocity planet searches. using data from four asteroseismological observation campaigns, we find a power law relationship between the noise impact of these oscillations on doppler velocities and both the luminosity - to - mass of the target stars, and observed integration times. including the impact of oscillation jitter should improve the quality of keplerian fits to doppler velocity data. the scale of the effect these oscillations have on doppler velocity measurements is smaller than that produced by stellar activity, but is most significant for giant and subgiant stars, and at short integration times ( i. e. less than a few minutes ). such short observation times tend to be used only for very bright stars. however, since it is these very same stars that tend to be targeted for the highest precision observations, as planet searches probe to lower and lower planet masses, oscillation noise for these stars can be significant and needs to be accounted for in observing strategies. | arxiv:0706.3548 |
we consider a gaussian beam ( gb ) resonant system for high frequency gravitational waves ( hfgws ) detection. at present, we find the optimal signal strength in theory through setting the magnetic component of gb in a standard gaussian form. under the synchro - resonance condition, we study the signal strength ( i. e., transverse perturbative photon fluxes ) from the relic hfgws ( predicted by ordinary inflationary model ) and the braneworld hfgws ( from braneworld scenarios ). both of them would generate potentially detectable transverse perturbative photon fluxes ( ppfs ). furthermore we find optimal system parameters and the relationship between frequency and effective width of energy fluxes accumulation. | arxiv:1411.1811 |
let $ \ omega \ subset \ mathbb { r } ^ { n + 1 } $, $ n \ geq 1 $, be an open set with $ s $ - ahlfors regular boundary $ \ partial \ omega $, for some $ s \ in ( 0, n ] $, such that either $ s = n $ and $ \ omega $ is a corkscrew domain with the pointwise john condition, or $ s < n $ and $ \ omega = \ mathbb { r } ^ { n + 1 } \ setminus e $, for some $ s $ - ahlfors regular set $ e \ subset \ mathbb { r } ^ { n + 1 } $. in this paper we provide a unifying method to construct varopoulos ' type extensions of $ bmo $ and $ l ^ p $ boundary functions. in particular, we show that a ) if $ f \ in bmo ( \ partial \ omega ) $, there exists $ f \ in c ^ \ infty ( \ omega ) $ such that $ dist ( x, \ omega ^ c ) | \ nabla f ( x ) | $ is uniformly bounded in $ \ omega $ and the carleson functional of $ dist ( x, \ omega ^ c ) ^ { s - n } | \ nabla f ( x ) | $ as well the sharp non - tangential maximal function of $ f $ are uniformly bounded on $ \ partial \ omega $ with norms controlled by the $ bmo $ - norm of $ f $, and $ f \ to f $ in a certain non - tangential sense $ \ mathcal h ^ s | _ { \ partial \ omega } $ - almost everywhere ; b ) if $ \ bar f \ in l ^ p ( \ partial \ omega ) $, $ 1 < p \ leq \ infty $, there exists $ \ bar f \ in c ^ \ infty ( \ omega ) $ such that the non - tangential maximal functions of $ \ bar f $ and $ dist ( \ cdot, \ omega ^ c ) | \ nabla \ bar f | $ as well as the carleson functional of $ dist ( \ cdot, \ omega ^ c ) ^ { s - n } | \ nabla \ bar f | $ are in $ l ^ p ( \ partial \ omega ) $ with norms controlled by the $ l ^ p $ - norm of $ \ bar | arxiv:2303.10717 |
many social networks exhibit assortative mixing so that the predictions of uncorrelated models might be inadequate. to analyze the role of assortativity we introduce an algorithm which changes correlations in a network and produces assortative mixing to a desired degree. this degree is governed by one parameter p. changing this parameter one can construct networks ranging from fully random ( p = 0 ) to totally assortative ( p = 1 ). we apply the algorithm to a barabasi - albert scale - free network and show that the degree of assortativity is an important parameter governing geometrical and transport properties of networks. thus, the diameter of the network and the clustering coefficient increase dramatically with the degree of assortativity. moreover, the concentration dependences of the size of the giant component in the node percolation problem for uncorrelated and assortative networks are strongly different. | arxiv:cond-mat/0405095 |
we address various topologies ( de bruijn, chordal ring, generalized petersen, meshes ) in various ways ( isometric embedding, embedding up to scale, embedding up to a distance ) in a hypercube or a half - hypercube. example of obtained embeddings : infinite series of hypercube embeddable bubble sort and double chordal rings topologies, as well as of regular maps. | arxiv:1507.02147 |
we show that constituency parsing benefits from unsupervised pre - training across a variety of languages and a range of pre - training conditions. we first compare the benefits of no pre - training, fasttext, elmo, and bert for english and find that bert outperforms elmo, in large part due to increased model capacity, whereas elmo in turn outperforms the non - contextual fasttext embeddings. we also find that pre - training is beneficial across all 11 languages tested ; however, large model sizes ( more than 100 million parameters ) make it computationally expensive to train separate models for each language. to address this shortcoming, we show that joint multilingual pre - training and fine - tuning allows sharing all but a small number of parameters between ten languages in the final model. the 10x reduction in model size compared to fine - tuning one model per language causes only a 3. 2 % relative error increase in aggregate. we further explore the idea of joint fine - tuning and show that it gives low - resource languages a way to benefit from the larger datasets of other languages. finally, we demonstrate new state - of - the - art results for 11 languages, including english ( 95. 8 f1 ) and chinese ( 91. 8 f1 ). | arxiv:1812.11760 |
starting with the ground - breaking work of cook ii, harbourne, migliore and nagel, there has been a lot of interest in unexpected hypersurfaces. in the last couple of months a considerable number of new examples and new phenomena has been observed and reported on. all examples studied so far had just one fat point. in this note we introduce a new series of examples, which establishes for the first time the existence of unexpected hypersurfaces with multiple fat points. the key underlying idea is to study fermat - type configurations of points in projective spaces. | arxiv:1812.04032 |
in this paper we prove that if $ x $ is a banach space, then for every lower semi - continuous bounded below function $ f, $ there exists a $ \ left ( \ varphi _ 1, \ varphi _ 2 \ right ) - $ convex function $ g, $ with arbitrarily small norm, such that $ f + g $ attains its strong minimum on $ x. $ this result extends some of the well - known varitional principles as that of ekeland [ 18 ], that of borwein - preiss [ 6 ] and that of deville - godefroy - zizler [ 14, 15 ]. | arxiv:1610.05915 |
a unitary description for wobbling motion in even - even and even - odd nuclei is presented. in both cases compact formulas for wobbling frequencies are derived. the accuracy of the harmonic approximation is studied for the yrast as well as for the excited bands in the even - even case. important results for the structure of the wave function and its behavior inside the two wells of the potential energy function corresponding to the bargmann representation are pointed out. applications to $ ^ { 158 } $ er and $ ^ { 163 } $ lu reveal a very good agreement with available data. indeed, the yrast energy levels in the even - even case and the first four triaxial super - deformed bands, tsd1, tsd2, tsd3 and tsd4, are realistically described. also, the results agree with the data for the e2 and m1 intra - as well as inter - band transitions. perspectives for the formalism development and an extensive application to several nuclei from various regions of the nuclides chart are presented. | arxiv:1711.01425 |
the microtubule network, an important part of the cytoskeleton, is constantly remodeled by alternating phases of growth and shrinkage of individual filaments. plus - end tracking proteins ( + tips ) interact with the microtubule and in many cases alter its dynamics. while it is established that the prototypal clip - 170 enhances microtubule stability by increasing rescues, the plus - end tracking mechanism is still under debate. we present a model for microtubule dynamics in which a rescue factor is dynamically added to the filament while growing. as a consequence, the filament shows aging behavior which should be experimentally accessible and thus allow one to exclude some hypothesized models of the inclusion of rescue factors at the microtubule plus end. additionally, we show the strong influence of the cell geometry on the quantitative results. | arxiv:0912.4611 |
collect disturbed samples. piston samplers, employing a thin - walled tube, are most commonly used to collect less disturbed samples. more advanced methods, such as the sherbrooke block sampler, are superior but expensive. coring frozen ground provides high - quality undisturbed samples from ground conditions, such as fill, sand, moraine, and rock fracture zones. geotechnical centrifuge modeling is another method of testing physical - scale models of geotechnical problems. the use of a centrifuge enhances the similarity of the scale model tests involving soil because soil ' s strength and stiffness are susceptible to the confining pressure. the centrifugal acceleration allows a researcher to obtain large ( prototype - scale ) stresses in small physical models. = = = foundation design = = = the foundation of a structure ' s infrastructure transmits loads from the structure to the earth. geotechnical engineers design foundations based on the load characteristics of the structure and the properties of the soils and bedrock at the site. generally, geotechnical engineers first estimate the magnitude and location of loads to be supported before developing an investigation plan to explore the subsurface and determine the necessary soil parameters through field and lab testing. following this, they may begin the design of an engineering foundation. the primary considerations for a geotechnical engineer in foundation design are bearing capacity, settlement, and ground movement beneath the foundations. = = = earthworks = = = geotechnical engineers are also involved in the planning and execution of earthworks, which include ground improvement, slope stabilization, and slope stability analysis. = = = = ground improvement = = = = various geotechnical engineering methods can be used for ground improvement, including reinforcement geosynthetics such as geocells and geogrids, which disperse loads over a larger area, increasing the soil ' s load - bearing capacity. through these methods, geotechnical engineers can reduce direct and long - term costs. = = = = slope stabilization = = = = geotechnical engineers can analyze and improve slope stability using engineering methods. slope stability is determined by the balance of shear stress and shear strength. a previously stable slope may be initially affected by various factors, making it unstable. nonetheless, geotechnical engineers can design and implement engineered slopes to increase stability. = = = = = slope stability analysis = = = = = stability analysis is needed to design engineered slopes and estimate the risk of slope failure in natural or designed slopes by determining the conditions under which the topmost mass | https://en.wikipedia.org/wiki/Geotechnical_engineering |
we obtain the basic results concerning the problem of constructing operator realizations of the formal differential expression $ \ nabla \ cdot a \ cdot \ nabla - b \ cdot \ nabla $ with measurable matrix $ a $ and vector field $ b $ having critical - order singularities as the generators of markov semigroups in $ l ^ p $ and $ c _ \ infty $. | arxiv:1709.08598 |
recent years have seen a growing interest in methods for predicting an unknown variable of interest, such as a subject ' s diagnosis, from medical images depicting its anatomical - functional effects. methods based on discriminative modeling excel at making accurate predictions, but are challenged in their ability to explain their decisions in anatomically meaningful terms. in this paper, we propose a simple technique for single - subject prediction that is inherently interpretable. it augments the generative models used in classical human brain mapping techniques, in which the underlying cause - effect relations can be encoded, with a multivariate noise model that captures dominant spatial correlations. experiments demonstrate that the resulting model can be efficiently inverted to make accurate subject - level predictions, while at the same time offering intuitive visual explanations of its inner workings. the method is easy to use : training is fast for typical training set sizes, and only a single hyperparameter needs to be set by the user. our code is available at https : / / github. com / chiara - mauri / interpretable - subject - level - prediction. | arxiv:2306.11107 |
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