text stringlengths 1 3.65k | source stringlengths 15 79 |
|---|---|
learning to communicate through interaction, rather than relying on explicit supervision, is often considered a prerequisite for developing a general ai. we study a setting where two agents engage in playing a referential game and, from scratch, develop a communication protocol necessary to succeed in this game. unlike previous work, we require that messages they exchange, both at train and test time, are in the form of a language ( i. e. sequences of discrete symbols ). we compare a reinforcement learning approach and one using a differentiable relaxation ( straight - through gumbel - softmax estimator ) and observe that the latter is much faster to converge and it results in more effective protocols. interestingly, we also observe that the protocol we induce by optimizing the communication success exhibits a degree of compositionality and variability ( i. e. the same information can be phrased in different ways ), both properties characteristic of natural languages. as the ultimate goal is to ensure that communication is accomplished in natural language, we also perform experiments where we inject prior information about natural language into our model and study properties of the resulting protocol. | arxiv:1705.11192 |
in this study, we discuss the relationship between two families of density - power - based divergences with functional degrees of freedom - - the h \ " { o } lder divergence and the functional density power divergence ( fdpd ) - - based on their intersection and generalization. these divergence families include the density power divergence and the $ \ gamma $ - divergence as special cases. first, we prove that the intersection of the h \ " { o } lder divergence and the fdpd is limited to a general divergence family introduced by jones et al. ( biometrika, 2001 ). subsequently, motivated by the fact that h \ " { o } lder ' s inequality is used in the proofs of nonnegativity for both the h \ " { o } lder divergence and the fdpd, we define a generalized divergence family, referred to as the $ \ xi $ - h \ " { o } lder divergence. the nonnegativity of the $ \ xi $ - h \ " { o } lder divergence is established through a combination of the inequalities used to prove the nonnegativity of the h \ " { o } lder divergence and the fdpd. furthermore, we derive an inequality between the composite scoring rules corresponding to different fdpds based on the $ \ xi $ - h \ " { o } lder divergence. finally, we prove that imposing the mathematical structure of the h \ " { o } lder score on a composite scoring rule results in the $ \ xi $ - h \ " { o } lder divergence. | arxiv:2504.17008 |
we revisit bjorken ' s model of spontaneous breakdown of lorentz invariance. we show that the model possesses zero mass, spin zero ( scalar ) nambu - goldstone boson, in addition to the zero mass, spin one ( vector ) photon. | arxiv:hep-th/0603009 |
angular - energy distributions are studied for charged leptons and neutrinos from the decays of polarised top quarks. a small admixture of v + a interactions is incorporated. the polarisation dependent part of the neutrino distribution which can be measured experimentally through the missing momentum is particularly sensitive towards deviations from the v - a structure. this result remains unaffected by qcd corrections which, however, cannot be neglected in a quantitative analysis. | arxiv:hep-ph/9403366 |
we investigate the casimir force between two dissimilar plane mirrors the material properties of which are described by drude or lorentz models. we calculate analytically the short and long distance asymptote of the force and relate its behavior to the influence of interacting surface plasmons. in particular we discuss conditions under which casimir repulsion could be achieved. | arxiv:0810.5469 |
we discuss recent results on the heavy fermion superconductor cerhin $ _ 5 $ which presents ideal conditions to study the strong coupling between the suppression of antiferromagnetic order and the appearance of unconventional superconductivity. the appearance of superconductivity as function of pressure is strongly connected to the suppression of the magnetic order. under magnetic field, the re - entrance of magnetic order inside the superconducting state shows that antiferromagnetism nucleates in the vortex cores. the suppression of antiferromagnetism in cerhin $ _ 5 $ by sn doping is compared to that under hydrostatic pressure. | arxiv:1104.3656 |
exact analytical calculations of eigenvalues and eigenstates are presented for quantum coupled double - well ( dw ) systems with razavy ' s hyperbolic potential. with the use of four kinds of initial wavepackets, we have calculated the tunneling period $ t $ and the orthogonality time $ \ tau $ which signifies a time interval for an initial state to evolve to its orthogonal state. we discuss the coupling dependence of $ t $ and $ \ tau $, and the relation between $ \ tau $ and the concurrence $ c $ which is a typical measure of the entanglement in two qubits. our calculations have shown that it is not clear whether the speed of quantum evolution may be measured by $ t $ or $ \ tau $ and that the evolution speed measured by $ \ tau $ ( or $ t $ ) is not necessarily increased with increasing $ c $. this is in contrast with the earlier study [ v. giovannetti, s. lloyd and l. maccone, europhys. lett. { \ bf 62 } ( 2003 ) 615 ] which pointed out that the evolution speed measured by $ \ tau $ is enhanced by the entanglement in the two - level model. | arxiv:1403.0543 |
derived from, statistical mechanics. the study of thermodynamics is fundamental to materials science. it forms the foundation to treat general phenomena in materials science and engineering, including chemical reactions, magnetism, polarizability, and elasticity. it explains fundamental tools such as phase diagrams and concepts such as phase equilibrium. = = = kinetics = = = chemical kinetics is the study of the rates at which systems that are out of equilibrium change under the influence of various forces. when applied to materials science, it deals with how a material changes with time ( moves from non - equilibrium to equilibrium state ) due to application of a certain field. it details the rate of various processes evolving in materials including shape, size, composition and structure. diffusion is important in the study of kinetics as this is the most common mechanism by which materials undergo change. kinetics is essential in processing of materials because, among other things, it details how the microstructure changes with application of heat. = = research = = materials science is a highly active area of research. together with materials science departments, physics, chemistry, and many engineering departments are involved in materials research. materials research covers a broad range of topics ; the following non - exhaustive list highlights a few important research areas. = = = nanomaterials = = = nanomaterials describe, in principle, materials of which a single unit is sized ( in at least one dimension ) between 1 and 1000 nanometers ( 10−9 meter ), but is usually 1 nm – 100 nm. nanomaterials research takes a materials science based approach to nanotechnology, using advances in materials metrology and synthesis, which have been developed in support of microfabrication research. materials with structure at the nanoscale often have unique optical, electronic, or mechanical properties. the field of nanomaterials is loosely organized, like the traditional field of chemistry, into organic ( carbon - based ) nanomaterials, such as fullerenes, and inorganic nanomaterials based on other elements, such as silicon. examples of nanomaterials include fullerenes, carbon nanotubes, nanocrystals, etc. = = = biomaterials = = = a biomaterial is any matter, surface, or construct that interacts with biological systems. biomaterials science encompasses elements of medicine, biology, chemistry, tissue engineering, and materials science. biomaterials can be derived either from nature or synthesized in a laboratory using a variety of | https://en.wikipedia.org/wiki/Materials_science |
the crab nebula, also known as tau a, is a polarized astronomical source at millimeter wavelengths. it has been used as a stable light source for polarization angle calibration in millimeter - wave astronomy. however, it is known that its intensity and polarization vary as a function of time at a variety of wavelengths. thus, it is of interest to verify the stability of the millimeter - wave polarization. if detected, polarization variability may be used to better understand the dynamics of tau ~ a, and for understanding the validity of tau ~ a as a calibrator. one intriguing application of such observation is to use it for the search of axion - like particles ( alps ). ultralight alps couple to photons through a chern - simons term, and induce a temporal oscillation in the polarization angle of linearly polarized sources. after assessing a number of systematic errors and testing for internal consistency, we evaluate the variability of the polarization angle of the crab nebula using 2015 and 2016 observations with the 150 ghz polarbear instrument. we place a median 95 % upper bound of polarization oscillation amplitude $ a < 0. 065 ^ \ circ $ over the oscillation frequencies from $ 0. 75 ~ \ mathrm { year } ^ { - 1 } $ to $ 0. 66 ~ \ mathrm { hour } ^ { - 1 } $. assuming that no sources other than alp are causing tau a ' s polarization angle variation, that the alp constitutes all the dark matter, and that the alp field is a stochastic gaussian field, this bound translates into a median 95 % upper bound of alp - photon coupling $ g _ { a \ gamma \ gamma } < 2. 16 \ times10 ^ { - 12 } \, \ mathrm { gev } ^ { - 1 } \ times ( m _ a / 10 ^ { - 21 } \ mathrm { ev } ) $ in the mass range from $ 9. 9 \ times10 ^ { - 23 } \ mathrm { ev } $ to $ 7. 7 \ times10 ^ { - 19 } \ mathrm { ev } $. this demonstrates that this type of analysis using bright polarized sources is as competitive as those using the polarization of cosmic microwave background in constraining alps. | arxiv:2403.02096 |
traditional methods for solvability region analysis can only have inner approximations with inconclusive conservatism. machine learning methods have been proposed to approach the real region. in this letter, we propose a deep active learning framework for power system solvability prediction. compared with the passive learning methods where the training is performed after all instances are labeled, the active learning selects most informative instances to be label and therefore significantly reduce the size of labeled dataset for training. in the active learning framework, the acquisition functions, which correspond to different sampling strategies, are defined in terms of the on - the - fly posterior probability from the classifier. the ieee 39 - bus system is employed to validate the proposed framework, where a two - dimensional case is illustrated to visualize the effectiveness of the sampling method followed by the full - dimensional numerical experiments. | arxiv:2007.13250 |
a new class of solutions of einstein ' s equations is derived providing a physically plausible hydrodynamic description of cosmological matter in the radiation era of the universe expansion. the solutions are characterized by the ltb metric with dissipative fluid sources, subjected to the following conditions : ( i ) tthe nonequilibrium state variables satisfy the equations of state of a mixture of relativistic and non - relativistic ideal gases, where the internal energy of the latter has been neglected, ( ii ) the particle numbers of the mixture components are independently conserved, ( iii ) the viscous stress is consistent with the transport equation and entropy balance law of extended irreversible thermodynamics with the coefficients of shear viscosity provided by kinetic theory. the jeans mass at decoupling is of the same order of magnitude as that of baryons dominated models. | arxiv:astro-ph/0103388 |
solitons are coherent structures that describe the nonlinear evolution of wave localizations in hydrodynamics, optics, plasma and bose - einstein condensates. while the peregrine breather is known to amplify a single localized perturbation of a carrier wave of finite amplitude by a factor of three, there is a counterpart solution on zero background known as the degenerate two - soliton which also leads to high amplitude maxima. in this study, we report several observations of such multi - soliton with doubly - localized peaks in a water wave flume. the data collected in this experiment confirm the distinctive attainment of wave amplification by a factor of two in good agreement with the dynamics of the nonlinear schr \ " odinger equation solution. advanced numerical simulations solving the problem of nonlinear free water surface boundary conditions of an ideal fluid quantify the physical limitations of the degenerate two - soliton in hydrodynamics. | arxiv:2011.13252 |
we introduce two two - player quantum pseudo - telepathy games based on two recently proposed all - versus - nothing ( avn ) proofs of bell ' s theorem [ a. cabello, phys. rev. lett. 95, 210401 ( 2005 ) ; phys. rev. a 72, 050101 ( r ) ( 2005 ) ]. these games prove that broadbent and methot ' s claim that these avn proofs do not rule out local - hidden - variable theories in which it is possible to exchange unlimited information inside the same light - cone ( quant - ph / 0511047 ) is incorrect. | arxiv:quant-ph/0511123 |
the arrival of gravitational wave astronomy and a growing number of time - domain focused observatories are set to lead to a increasing number of detections of short gamma - ray bursts ( grbs ) launched with a moderate inclination to earth. being nearby events, these are also prime candidates for very long - term follow - up campaigns and very - long - baseline interferometry ( vlbi ), which has implications for multi - messenger modelling, data analysis, and statistical inference methods applied to these sources. here we present a comprehensive modelling update that directly incorporates into afterglowpy astrometric observations of the grb position, poissonian statistics for faint sources, and modelling of a trans - relativistic population of electrons. we use the revolutionary event gw170817 to demonstrate the impact of these extensions both for the best - fit physics parameters and model selection methods that assess the statistical significance of additional late - time emission components. by including in our analysis the latest chandra x - ray observations of grb 170817a, we find only weak evidence ( less than two sigma ) for a new emission component at late times, which makes for a slightly more natural fit to the centroid evolution and prediction for the external medium density. | arxiv:2310.02328 |
killing spinors of space - time bps configurations play an important role in quantization of theories with the fermionic worldvolume local symmetry. we show here how it works for the gs superstring, bst supermembrane and m - 5 - brane. we show that the non - linear generalization of the ( 2, 0 ) d = 6 tensor supermultiplet action is the m - 5 - brane action in a killing gauge. for d - p - branes the novel feature of quantization is that they can be quantized lorentz covariantly, in particular, for d - 0 - brane a gauge exists where the action is covariant and free. we present a general condition on possible choice of gauges for the kappa - symmetric branes. | arxiv:hep-th/9709202 |
the btz black hole belongs to a family of locally three - dimensional anti - de sitter ( ads $ _ 3 $ ) spacetimes labeled by their mass $ m $ and angular momentum $ j $. the case $ m \ ell \ geq | j | $, where $ \ ell $ is the anti - de sitter radius, provides the black hole. extending the metric to other values of of $ m $ and $ j $ leads to geometries with the same asymptotic behavior and global symmetries, but containing a naked singularity at the origin. the case $ m \ ell \ leq - | j | $ corresponds to spinning conical singularities that are reasonably well understood. here we examine the remaining case, that is $ - | j | < m \ ell < | j | $. these naked singularities are mathematically acceptable solutions describing classical spacetimes. they are obtained by identifications of the covering pseudosphere in $ \ mathbb { r } ^ { 2, 2 } $ and are free of closed timelike curves. here we study the causal structure and geodesics around these \ textit { overspinning } geometries. we present a review of the geodesics for the entire btz family. the geodesic equations are completely integrated, and the solutions are expressed in terms of elementary functions. special attention is given to the determination of circular geodesics, where new results are found. according to the radial bounds, eight types of noncircular geodesics appear in the btz spacetimes. for the case of overspinning naked singularity, null and spacelike geodesics can reach infinity passing by a point nearest to the singularity, others extend from the central singularity to infinity, and others still have a radial upper bound and terminate at the singularity. timelike geodesics cannot reach infinity ; they either loop around the singularity or fall into it. the spatial projections of the geodesics ( orbits ) exhibit self - intersections, whose number is determined for null and spacelike geodesics, and it is found a special class of timelike geodesics whose spatial projections are closed. | arxiv:2105.06488 |
recognition and binding of specific sites on dna by proteins is central for many cellular functions such as transcription, replication, and recombination. in the process of recognition, a protein rapidly searches for its specific site on a long dna molecule and then strongly binds this site. here we aim to find a mechanism that can provide both a fast search ( 1 - 10 sec ) and high stability of the specific protein - dna complex ( $ k _ d = 10 ^ { - 15 } - 10 ^ { - 8 } $ m ). earlier studies have suggested that rapid search involves the sliding of a protein along the dna. here we consider sliding as a one - dimensional ( 1d ) diffusion in a sequence - dependent rough energy landscape. we demonstrate that, in spite of the landscape ' s roughness, rapid search can be achieved if 1d sliding is accompanied by 3d diffusion. we estimate the range of the specific and non - specific dna - binding energy required for rapid search and suggest experiments that can test our mechanism. we show that optimal search requires a protein to spend half of time sliding along the dna and half diffusing in 3d. we also establish that, paradoxically, realistic energy functions cannot provide both rapid search and strong binding of a rigid protein. to reconcile these two fundamental requirements we propose a search - and - fold mechanism that involves the coupling of protein binding and partial protein folding. proposed mechanism has several important biological implications for search in the presence of other proteins and nucleosomes, simultaneous search by several proteins etc. proposed mechanism also provides a new framework for interpretation of experimental and structural data on protein - dna interactions. | arxiv:q-bio/0402005 |
we present a theory for carrier induced ferromagnetism in diluted magnetic semi - conductor ( dms ). our approach treats on equal footing quantum fluctuations within the rpa approximation and disorder within cpa. this method allows for the calculation of $ t _ c $, magnetization and magnon spectrum as a function of hole, impurity concentration and temperature. it is shown that, sufficiently close to $ t _ c $, and within our decoupling scheme ( tyablicov type ) the cpa for the itinerant electron gas reduces to the virtual crystal approximation. this allows, in the low impurity concentration and low density of carriers to provide analytical expression for $ t _ c $. for illustration, we consider the case of $ ga _ { 1 - c } mn _ { c } as $ and compare our results with available experimental data. | arxiv:cond-mat/0202111 |
discrete - modulated continuous - variable quantum key distribution protocols are promising candidates for large - scale deployment due to the large technological overlap with deployed modern optical communication devices. the security of discrete modulation schemes has previously analyzed in the ideal detector scenario in the asymptotic limit. in this work, we calculate asymptotic key rates against collective attacks in the trusted detector noise scenario. our results show that we can thus cut out most of the effect of detector noise and obtain asymptotic key rates similar to those had we access to ideal detectors. | arxiv:2006.06166 |
in this study, we present a non - contact respiratory anomaly detection method using incoherent light - wave signals reflected from the chest of a mechanical robot that can breathe like human beings. in comparison to existing radar and camera - based sensing systems for vitals monitoring, this technology uses only a low - cost ubiquitous infrared light source and sensor. this light - wave sensing system recognizes different breathing anomalies from the variations of light intensity reflected from the chest of the robot within a 0. 5m - 1. 5m range with an average classification accuracy of up to 96. 6 % using machine learning. | arxiv:2311.01367 |
the outbreak of covid - 19 caused millions of deaths worldwide, and the number of total infections is still rising. it is necessary to identify some potentially effective drugs that can be used to prevent the development of severe symptoms or even death for those infected. fortunately, many efforts have been made, and several effective drugs have been identified. the rapidly increasing amount of data is of great help for training an effective and specific deep learning model. in this study, we propose a multi - task deep learning model for the purpose of screening commercially available and effective inhibitors against sars - cov - 2. first, we pretrained a model on several heterogenous protein - ligand interaction datasets. the model achieved competitive results on some benchmark datasets. next, a coronavirus - specific dataset was collected and used to fine - tune the model. then, the fine - tuned model was used to select commercially available drugs against sars - cov - 2 protein targets. overall, twenty compounds were listed as potential inhibitors. we further explored the model interpretability and observed the predicted important binding sites. based on this prediction, molecular docking was also performed to visualize the binding modes of the selected inhibitors. | arxiv:2003.00728 |
machine learning classification tasks often benefit from predicting a set of possible labels with confidence scores to capture uncertainty. however, existing methods struggle with the high - dimensional nature of the data and the lack of well - calibrated probabilities from modern classification models. we propose a novel conformal prediction method that employs a rank - based score function suitable for classification models that predict the order of labels correctly, even if not well - calibrated. our approach constructs prediction sets that achieve the desired coverage rate while managing their size. we provide a theoretical analysis of the expected size of the conformal prediction sets based on the rank distribution of the underlying classifier. through extensive experiments, we demonstrate that our method outperforms existing techniques on various datasets, providing reliable uncertainty quantification. our contributions include a novel conformal prediction method, theoretical analysis, and empirical evaluation. this work advances the practical deployment of machine learning systems by enabling reliable uncertainty quantification. | arxiv:2407.04407 |
we give an explicit description of the multiplicities of codimension two strata of discriminantal arrangements introduced by manin and schechtman. as applications, we discuss the connection of these results with properties of gale transform and we calculate the fundamental groups of the complements to discriminantal arrangements. | arxiv:1601.06475 |
for every proper geodesic space $ x $ we introduce its quasi - geometric boundary $ \ partial _ { qg } x $ with the following properties : 1. every geodesic ray $ g $ in $ x $ converges to a point of the boundary $ \ partial _ { qg } x $ and for every point $ p $ in $ \ partial _ { qg } x $ there is a geodesic ray in $ x $ converging to $ p $, 2. the boundary $ \ partial _ { qg } x $ is compact metric, 3. the boundary $ \ partial _ { qg } x $ is an invariant under quasi - isometric equivalences, 4. a quasi - isometric embedding induces a continuous map of quasi - geodesic boundaries, 5. if $ x $ is gromov hyperbolic, then $ \ partial _ { qg } x $ is the gromov boundary of $ x $. 6. if $ x $ is a croke - kleiner space, then $ \ partial _ { qg } x $ is a point. | arxiv:2207.13672 |
in this work, a rigorous proof of the orbital stability of the black soliton solution of the quintic gross - pitaevskii equation in one spatial dimension is obtained. we first build and show explicitly black and dark soliton solutions and we prove that the corresponding ginzburg - landau energy is coercive around them by using some orthogonality conditions related to perturbations of the black and dark solitons. the existence of suitable perturbations around black and dark solitons satisfying the required orthogonality conditions is deduced from an implicit function theorem. in fact, these perturbations involve dark solitons with sufficiently small speeds and some proportionality factors ari \ - sing from the explicit expression of their spatial derivative. we are also able to control the evolution of the modulation parameters along the quintic gross - pitaevskii flow by estimating their growth in time. as a direct consequence, we also prove the orbital stability of the dark soliton in a small speed interval. | arxiv:2003.09994 |
we identified star clusters in archived hst / wfpc2 images of the merger and ultra - luminous infrared galaxy ngc 6240, with the aim of investigating whether star cluster properties ( luminosity, age and mass ) in such an extreme environment differ from those of clusters in less luminous starburst galaxies. we found 54 star clusters in all of the f450w, f547m and f814w exposures, of which 41 are located in the main body of ngc 6240 and 13 in the galactic tails. given that only two colours are available to derive two independent variables ( cluster reddening and age ), we adopted an ad hoc procedure to statistically derive cluster parameters under the assumption that the cluster metallicity is lmc - like. the colours of each cluster are fitted to starburst99 models of fixed mass and variable ages and reddenings. all cluster reddening and age solutions with chi squared < 1 are considered to be consistent with the data. masses are derived by scaling the luminosity of the models with best - fit chi squared < 1 by the observed v luminosity, after correction for reddening and distance. we infer that the most probable age of the observed clusters is ( 5 - 13 ) myr and their most probable mass is about ( 1 - 2 ) e05 solar masses. comparison with star clusters in starburst galaxies seems to point to more massive clusters being formed in more massive galaxies and gas - rich mergers, while the overall cluster mass distribution might be relatively independent of the details of the associated starburst where dense, massive clusters preferentially form. | arxiv:astro-ph/0306446 |
we present a generalization of weinstein ' s morphism defined on $ \ pi _ { 2k - 1 } ( \ textup { ham } ( m, \ omega ) ) $. we use this morphism to show that for $ n \ geq 2 $ the lie group $ su ( 2 ) $ induces an element in $ \ pi _ 3 ( \ textup { ham } ( \ mathbb { c } p ^ n, \ omega _ \ textup { fs } ) ) $ of infinite order. | arxiv:2312.05091 |
we present ipchain, a blockchain to store the allocations and delegations of ip addresses, with the aim of easing the deployment of secure interdomain routing systems. interdomain routing security is of vital importance to the internet since it prevents unwanted traffic redirections. ipchain makes use of blockchains ' properties to provide flexible trust models and simplified management when compared to existing systems. in this paper we argue that proof of stake is a suitable consensus algorithm for ipchain due to the unique incentive structure of this use - case. we have implemented and evaluated ipchain ' s performance and scalability storing around 150k ip prefixes in a 1gb chain. | arxiv:1805.04439 |
this thesis reviews the conjectured holographic relation between entanglement and gravity due to mark van raamsdonk and collaborators. it is accounted how the linearized einstein equations both with and without matter in a d + 1 - dimensional ads background can be derived from the first law of entanglement entropy in a d - dimensional cft. this derivation builds on the ryu - takayanagi formula that relates entanglement entropy for cft subsystems to extremal surfaces in the ads bulk. the relation between gravity and entanglement is also corroborated by a qualitative investigation of the duality between the thermofield double state and the maximally extended ads / schwarzschild black hole using the bekenstein - hawking formula. furthermore, this qualitative argument is generalized to generic cft states with a classical spacetime dual using the ryu - takayanagi. the thesis also reviews the most relevant prerequisites for this holographic relation between gravity and entanglement : anti - de sitter spacetime, entanglement and entanglement entropy, gauge / gravity duality, the ryu - takayanagi formula, and linearized gravity. | arxiv:1711.10854 |
we focus on the existence and uniqueness of the three - dimensional landau - lifshitz - bloch equation supplemented with the initial data in besov space $ \ dot { b } _ { 2, 1 } ^ { \ frac { 3 } { 2 } } $. utilizing a new commutator estimate, we establish the local existence and uniqueness of strong solutions for any initial data in $ \ dot { b } _ { 2, 1 } ^ { \ frac { 3 } { 2 } } $. when the initial data is small enough in $ \ dot { b } _ { 2, 1 } ^ { \ frac { 3 } { 2 } } $, we obtain the global existence and uniqueness. furthermore, we also establish a blow - up criterion of the solution to the landau - lifshitz - bloch equation and then we prove the global existence of strong solutions in sobolev space under a new condition based on the blow - up criterion. | arxiv:2211.03056 |
the design of products and services such as a smart doorbell, demonstrating video analytics software / algorithm functionality, is expected to address a new kind of requirements such as designing a scalable solution while considering the trade - off between cost and accuracy ; a flexible architecture to deploy new ai - based models or update existing models, as user requirements evolve ; as well as seamlessly integrating different kinds of user interfaces and devices. to address these challenges, we propose a smart doorbell that orchestrates video analytics across edge and cloud resources. the proposal uses aws as a base platform for implementation and leverages commercially available off - the - shelf ( cots ) affordable devices such as raspberry pi in the form of an edge device. | arxiv:2010.07680 |
we have undertaken the study of the elemental abundances and kinematic properties of a metal - poor sample of candidate thick - disk stars selected from the rave spectroscopic survey of bright stars to differentiate among the present scenarios of the formation of the thick disk. in this paper, we report on a sample of 214 red giant branch, 31 red clump / horizontal branch, and 74 main - sequence / sub - giant branch metal - poor stars, which serves to augment our previous sample of only giant stars. we find that the thick disk [ alpha / fe ] ratios are enhanced, and have little variation ( < 0. 1 dex ), in agreement with our previous study. the augmented sample further allows, for the first time, investigation of the gradients in the metal - poor thick disk. for stars with [ fe / h ] < - 1. 2, the thick disk shows very small gradients, < 0. 03 + / - 0. 02 dex / kpc, in alpha - enhancement, while we find a + 0. 01 + / - 0. 04 dex / kpc radial gradient and a - 0. 09 + / - 0. 05 dex / kpc vertical gradient in iron abundance. in addition, we show that the peak of the distribution of orbital eccentricities for our sample agrees better with models in which the stars that comprise the thick disk were formed primarily in the galaxy, with direct accretion of stars contributing little. our results thus disfavor direct accretion of stars from dwarf galaxies into the thick disk as a major contributor to the thick disk population, but cannot discriminate between alternative models for the thick disk, such as those that invoke high - redshift ( gas - rich ) mergers, heating of a pre - existing thin stellar disk by a minor merger, or efficient radial migration of stars. | arxiv:1105.3691 |
belief propagation is a widely used message passing method for the solution of probabilistic models on networks such as epidemic models, spin models, and bayesian graphical models, but it suffers from the serious shortcoming that it works poorly in the common case of networks that contain short loops. here we provide a solution to this long - standing problem, deriving a belief propagation method that allows for fast calculation of probability distributions in systems with short loops, potentially with high density, as well as giving expressions for the entropy and partition function, which are notoriously difficult quantities to compute. using the ising model as an example, we show that our approach gives excellent results on both real and synthetic networks, improving significantly on standard message passing methods. we also discuss potential applications of our method to a variety of other problems. | arxiv:2009.12246 |
deep learning models have become a powerful tool in knee angle estimation for lower limb prostheses, owing to their adaptability across various gait phases and locomotion modes. current methods utilize multi - layer perceptrons ( mlp ), long - short term memory networks ( lstm ), and convolutional neural networks ( cnn ), predominantly analyzing motion information from the thigh. contrary to these approaches, our study introduces a holistic perspective by integrating whole - body movements as inputs. we propose a transformer - based probabilistic framework, termed the angle estimation probabilistic model ( aepm ), that offers precise angle estimations across extensive scenarios beyond walking. aepm achieves an overall rmse of 6. 70 degrees, with an rmse of 3. 45 degrees in walking scenarios. compared to the state of the art, aepm has improved the prediction accuracy for walking by 11. 31 %. our method can achieve seamless adaptation between different locomotion modes. also, this model can be utilized to analyze the synergy between the knee and other joints. we reveal that the whole body movement has valuable information for knee movement, which can provide insights into designing sensors for prostheses. the code is available at https : / / github. com / penway / beyond - gait - aepm. | arxiv:2404.06772 |
this paper is devoted to model selection in logistic regression. we extend the model selection principle introduced by birg \ ' e and massart ( 2001 ) to logistic regression model. this selection is done by using penalized maximum likelihood criteria. we propose in this context a completely data - driven criteria based on the slope heuristics. we prove non asymptotic oracle inequalities for selected estimators. theoretical results are illustrated through simulation studies. | arxiv:1508.07537 |
in this paper it is shown that the space of tight geodesic segments connecting any two vertices in a complex of cycles has finite, uniformly bounded dimension. the dimension is defined in terms of a discrete analogue of jacobi fields, which are explicitly constructed and shown to give a complete description of the entire space of tight geodesics. jacobi fields measure the extent to which geodesic stability breaks down. unlike most finiteness properties of curve complexes, the arguments presented here do not rely on hyperbolicity, but rather on structures similar to morse theory. | arxiv:1302.0147 |
we study the magnetization plateau state of the three - leg spin - 1 / 2 tube in the strong rung coupling region, where s _ 3 - symmetry breakings and low - energy chirality degree of freedom play crucial roles. on the basis of the effective chirality model and density matrix renormalization group, we clarify that, as the leg coupling increases, the chirality liquid with gapless non - magnetic excitations, the spin imbalance phase and the vector - spin - chirality ordered phase emerge without closing the plateau spin gap. the relevance of these results to experiments is also discussed. | arxiv:1109.0063 |
quantum communications technologies require a network of quantum processors connected with low loss and low noise communication channels capable of distributing entangled states. superconducting microwave qubits operating in cryogenic environments have emerged as promising candidates for quantum processor nodes. however, scaling these systems is challenging because they require bulky microwave components with high thermal loads that can quickly overwhelm the cooling power of a dilution refrigerator. telecommunication frequency optical signals, meanwhile, can be fabricated in significantly smaller form factors while avoiding challenges due to high signal loss, noise sensitivity, and thermal loads due to their high carrier frequency and propagation in silica optical fibers. transduction of information via coherent links between optical and microwave frequencies is therefore critical to leverage the advantages of optics for superconducting microwave qubits, while also enabling superconducting processors to be linked with low - loss optical interconnects. here, we demonstrate coherent optical control of a superconducting qubit. we achieve this by developing a microwave - optical quantum transducer that operates with up to 1. 18 % conversion efficiency with low added microwave noise, and demonstrate optically - driven rabi oscillations in a superconducting qubit. | arxiv:2310.16155 |
in this article, we present an approach which allows to take into account the effect of extreme values in the modeling of financial asset returns and in the valorisation of associeted options. specifically, the marginal distribution of assets returns is modeled by a mixture of two gaussiens distributions. moreover, we model the joint dependence structure of the returns using an extremal copula which is suitable for our financial data. applications are made on the atos and dassault systems actions of the cac40 index. monte - carlo method is used to compute the values of some equity options : the call on maximum, the call on minimum, the digital option and the spreads option with the basket ( atos, dassault systems ). | arxiv:2105.10599 |
this work presents a novel method to generate secret keys shared between a legitimate node pair ( alice and bob ) to safeguard the communication between them from an unauthorized node ( eve ). to this end, we exploit the { \ it reciprocal carrier frequency offset } ( cfo ) between the legitimate node pair to extract common randomness out of it to generate shared secret keys. the proposed key generation algorithm involves standard steps : the legitimate nodes exchange binary phase - shift keying ( bpsk ) signals to perform blind cfo estimation on the received signals, and do equi - probable quantization of the noisy cfo estimates followed by information reconciliation - - to distil a shared secret key. furthermore, guided by the allan deviation curve, we distinguish between the two frequency - stability regimes - - - when the randomly time - varying cfo process i ) has memory, ii ) is memoryless ; thereafter, we compute the key generation rate for both regimes. simulation results show that the key disagreement rate decreases exponentially with increase in the signal to noise ratio of the link between alice and bob. additionally, the decipher probability of eve decreases as soon as either of the two links observed by the eve becomes more degraded compared to the link between alice and bob. | arxiv:1902.10998 |
recent advancements in chain - of - thought prompting have facilitated significant breakthroughs for large language models ( llms ) in complex reasoning tasks. current research enhances the reasoning performance of llms by sampling multiple reasoning chains and ensembling based on the answer frequency. however, this approach fails in scenarios where the correct answers are in the minority. we identify this as a primary factor constraining the reasoning capabilities of llms, a limitation that cannot be resolved solely based on the predicted answers. to address this shortcoming, we introduce a hierarchical reasoning aggregation framework aor ( aggregation of reasoning ), which selects answers based on the evaluation of reasoning chains. additionally, aor incorporates dynamic sampling, adjusting the number of reasoning chains in accordance with the complexity of the task. experimental results on a series of complex reasoning tasks show that aor outperforms prominent ensemble methods. further analysis reveals that aor not only adapts various llms but also achieves a superior performance ceiling when compared to current methods. | arxiv:2405.12939 |
formalisms for specifying statistical models, such as probabilistic - programming languages, typically consist of two components : a specification of a stochastic process ( the prior ), and a specification of observations that restrict the probability space to a conditional subspace ( the posterior ). use cases of such formalisms include the development of algorithms in machine learning and artificial intelligence. we propose and investigate a declarative framework for specifying statistical models on top of a database, through an appropriate extension of datalog. by virtue of extending datalog, our framework offers a natural integration with the database, and has a robust declarative semantics. our datalog extension provides convenient mechanisms to include numerical probability functions ; in particular, conclusions of rules may contain values drawn from such functions. the semantics of a program is a probability distribution over the possible outcomes of the input database with respect to the program ; these outcomes are minimal solutions with respect to a related program with existentially quantified variables in conclusions. observations are naturally incorporated by means of integrity constraints over the extensional and intensional relations. we focus on programs that use discrete numerical distributions, but even then the space of possible outcomes may be uncountable ( as a solution can be infinite ). we define a probability measure over possible outcomes by applying the known concept of cylinder sets to a probabilistic chase procedure. we show that the resulting semantics is robust under different chases. we also identify conditions guaranteeing that all possible outcomes are finite ( and then the probability space is discrete ). we argue that the framework we propose retains the purely declarative nature of datalog, and allows for natural specifications of statistical models. | arxiv:1412.2221 |
we investigate collective excitations of density fluctuations and a dynamic density structure factor in a mixture of bose and fermi gases in a normal phase. with decreasing temperature, we find that the frequency of the collective excitation deviates from that of the hydrodynamic sound mode. even at temperature much lower than the fermi temperature, the collective mode frequency does not reach the collisionless limit analogous to zero sound in a fermi gas, because of collisions between bosons and fermions. | arxiv:1807.06747 |
we study the time - evolution of initially trapped bose - einstein condensates in the gross - pitaevskii regime. under a physically motivated assumption on the energy of the initial data, we show that condensation is preserved by the many - body evolution and that the dynamics of the condensate wave function can be described by the time - dependent gross - pitaevskii equation. with respect to previous works, we provide optimal bounds on the rate of condensation ( i. e. on the number of excitations of the bose - einstein condensate ). to reach this goal, we combine the method of \ cite { lns }, where fluctuations around the hartree dynamics for $ n $ - particle initial data in the mean - field regime have been analyzed, with ideas from \ cite { bds }, where the evolution of fock - space initial data in the gross - pitaevskii regime has been considered. | arxiv:1702.05625 |
we prove a local limit theorem for nearest neighbours random walks in stationary random environment of conductances on z without using any of both classic assumptions of uniform ellipticity and independence on the conductances. besides the central limit theorem, we use discrete differential " nash - type inequalities " associated with the hausdorff ' s representation of the completely decreasing sequences. | arxiv:1302.0225 |
we discuss the design and current status of the ciza survey, the first systematic x - ray search for clusters of galaxies in the galactic plane region. so far, we have compiled a sample of more than 70 x - ray selected clusters at | b | < 20 deg, 80 % of which were previously unknown. upon its completion the ciza cluster catalogue will complement the existing galaxy surveys in the galactic plane region and allow a fresh look at large - scale structure and local streaming motions. | arxiv:astro-ph/0001319 |
predicting drug properties is key in drug discovery to enable de - risking of assets before expensive clinical trials, and to find highly active compounds faster. interest from the machine learning community has led to the release of a variety of benchmark datasets and proposed methods. however, it remains unclear for practitioners which method or approach is most suitable, as different papers benchmark on different datasets and methods, leading to varying conclusions that are not easily compared. our large - scale empirical study links together numerous earlier works on different datasets and methods ; thus offering a comprehensive overview of the existing property classes, datasets, and their interactions with different methods. we emphasise the importance of uncertainty quantification and the time and therefore cost of applying these methods in the drug development decision - making cycle. we discover that the best method depends on the dataset, and that engineered features with classical ml methods often outperform deep learning. specifically, qsar datasets are typically best analysed with classical methods such as gaussian processes while admet datasets are sometimes better described by trees or deep learning methods such as graph neural networks or language models. our work highlights that practitioners do not yet have a straightforward, black - box procedure to rely on, and sets the precedent for creating practitioner - relevant benchmarks. deep learning approaches must be proven on these benchmarks to become the practical method of choice in drug property prediction. | arxiv:2309.17161 |
we revisit the analysis of effective field theories resulting from non - supersymmetric perturbations to supersymmetric flux compactifications of the type - iib superstring with an eye towards those resulting from the backreaction of a small number of anti - d3 - branes. independently of the background, we show that the low - energy lagrangian describing the fluctuations of a stack of probe d3 - branes exhibits soft supersymmetry breaking, despite perturbations to marginal operators that were not fully considered in some previous treatments. we take this as an indication that the breaking of supersymmetry by anti - d3 - branes or other sources may be spontaneous rather than explicit. in support of this, we consider the action of an anti - d3 - brane probing an otherwise supersymmetric configuration and identify a candidate for the corresponding goldstino. | arxiv:1206.0754 |
withdrawn ; originally put in incomplete form without permission | arxiv:hep-ph/9511359 |
we study the problem of deleting the smallest set $ s $ of vertices ( resp. edges ) from a given graph $ g $ such that the induced subgraph ( resp. subgraph ) $ g \ setminus s $ belongs to some class $ \ mathcal { h } $. we consider the case where graphs in $ \ mathcal { h } $ have treewidth bounded by $ t $, and give a general framework to obtain approximation algorithms for both vertex and edge - deletion settings from approximation algorithms for certain natural graph partitioning problems called $ k $ - subset vertex separator and $ k $ - subset edge separator, respectively. for the vertex deletion setting, our framework combined with the current best result for $ k $ - subset vertex separator, yields a significant improvement in the approximation ratios for basic problems such as $ k $ - treewidth vertex deletion and planar - $ f $ vertex deletion. our algorithms are simpler than previous works and give the first uniform approximation algorithms under the natural parameterization. for the edge deletion setting, we give improved approximation algorithms for $ k $ - subset edge separator combining ideas from lp relaxations and important separators. we present their applications in bounded - degree graphs, and also give an apx - hardness result for the edge deletion problems. | arxiv:1804.01366 |
background : medical images are more difficult to acquire and annotate than natural images, which results in data augmentation technologies often being used in medical image segmentation tasks. most data augmentation technologies used in medical segmentation were originally developed on natural images and do not take into account the characteristic that the overall layout of medical images is standard and fixed. methods : based on the characteristics of medical images, we developed the cutting - splicing data augmentation ( cs - da ) method, a novel data augmentation technology for medical image segmentation. cs - da augments the dataset by splicing different position components cut from different original medical images into a new image. the characteristics of the medical image result in the new image having the same layout as and similar appearance to the original image. compared with classical data augmentation technologies, cs - da is simpler and more robust. moreover, cs - da does not introduce any noise or fake information into the newly created image. results : to explore the properties of cs - da, many experiments are conducted on eight diverse datasets. on the training dataset with the small sample size, cs - da can effectively increase the performance of the segmentation model. when cs - da is used together with classical data augmentation technologies, the performance of the segmentation model can be further improved and is much better than that of cs - da and classical data augmentation separately. we also explored the influence of the number of components, the position of the cutting line, and the splicing method on the cs - da performance. conclusions : the excellent performance of cs - da in the experiment has confirmed the effectiveness of cs - da, and provides a new data augmentation idea for the small sample segmentation task. | arxiv:2210.09099 |
the xview2 competition and xbd dataset spurred significant advancements in overhead building damage detection, but the competition ' s pixel level scoring can lead to reduced solution performance in areas with tight clusters of buildings or uninformative context. we seek to advance automatic building damage assessment for disaster relief by proposing an auxiliary challenge to the original xview2 competition. this new challenge involves a new dataset and metrics indicating solution performance when damage is more local and limited than in xbd. our challenge measures a network ' s ability to identify individual buildings and their damage level without excessive reliance on the buildings ' surroundings. methods that succeed on this challenge will provide more fine - grained, precise damage information than original xview2 solutions. the best - performing xview2 networks ' performances dropped noticeably in our new limited / local damage detection task. the common causes of failure observed are that ( 1 ) building objects and their classifications are not separated well, and ( 2 ) when they are, the classification is strongly biased by surrounding buildings and other damage context. thus, we release our augmented version of the dataset with additional object - level scoring metrics ( https : / / drive. google. com / drive / folders / 1vuqzuag6 - yo8r5j4ocx3zrpa _ fv9aadx? usp = sharing ) to test independence and separability of building objects, alongside the pixel - level performance metrics of the original competition. we also experiment with new baseline models which improve independence and separability of building damage predictions. our results indicate that building damage detection is not a fully - solved problem, and we invite others to use and build on our dataset augmentations and metrics. | arxiv:2212.13876 |
the task of preserving entanglement against noises is of crucial importance for both quantum communication and quantum information transfer. to this aim, quantum error correction ( qec ) codes may be employed to compensate, at least partially, the detriments induced by environmental noise that can be modelled as a bit - flip or a phase - flip error channel. in this paper we investigate the effects of the simple three - qubit qec codes to restore entanglement and nonlocality in a two - qubit system and consider two practical applications : superdense coding and quantum teleportation. though the considered three - qubit qec codes are known to perfectly work in the presence of very small noise, we show that they can avoid the sudden death of entanglement and improve the performance of the addressed protocols also for larger noise amplitudes. | arxiv:2211.11295 |
software transactional memory implementations which allow transactions to work on inconsistent states of shared data, risk to cause application visible errors such as memory access violations or endless loops. hence, many implementations rely on repeated incremental validation of every read of the transaction to always guarantee for a consistent view of shared data. because this eager validation technique generates significant processing costs several proposals have been published to establish a sandbox for transactions, which transparently prevents or suppresses those errors and thereby allows to reduce the frequency of in - flight validations. the most comprehensive sandboxing concept of transactions in software transactional memory based on deferred updates and considering unmanaged languages, integrates multiple techniques such as signal interposition, out - of - band validation and static and dynamic instrumentation. the latter comprises the insertion of a validation barrier in front of every direct write which addresses the execution stack of the thread and potentially results from unvalidated reads. this paper basically results from a review of this sandboxing approach, which revealed some improvements for sandboxing on c / c + +. based on knowledge about the runtime environment and the compiler an error model has been developed to identify critical paths to application visible errors. this analysis lead to a concept for stack protection with less frequent validation, an alternative out - of - band validation technique and revealed additional risks of so - called waivered regions without instrumentation inside transactions. | arxiv:1409.5313 |
dissimilarity measures for ( possibly weighted ) phylogenetic trees based on the comparison of their vectors of path lengths between pairs of taxa, have been present in the systematics literature since the early seventies. but, as far as rooted phylogenetic trees goes, these vectors can only separate non - weighted binary trees, and therefore these dissimilarity measures are metrics only on this class. in this paper we overcome this problem, by splitting in a suitable way each path length between two taxa into two lengths. we prove that the resulting splitted path lengths matrices single out arbitrary rooted phylogenetic trees with nested taxa and arcs weighted in the set of positive real numbers. this allows the definition of metrics on this general class by comparing these matrices by means of metrics in spaces of real - valued $ n \ times n $ matrices. we conclude this paper by establishing some basic facts about the metrics for non - weighted phylogenetic trees defined in this way using $ l ^ p $ metrics on these spaces of matrices. | arxiv:0806.2035 |
in this paper a new connection between the discrete conformal geometry problem of disk pattern construction and the continuous conformal geometry problem of metric uniformization is presented. in a nutshell, we discuss how to construct disk patterns by optimizing an objective function, which turns out to be intimately related to hyperbolic volume. with the use of random delaunay triangulations we then average this objective function to construct an objective function on the metrics conformal to a fixed one. finally using this averaged objective function we may reprove the uniformization theorem in two dimensions. | arxiv:math/0010316 |
1057 globular cluster candidates have been identified in a wfpc2 image of the inner region of m87. the globular cluster luminosity function ( gclf ) can be well fit by a gaussian profile with a mean value of m _ v ^ 0 = 23. 67 + / - 0. 07 mag and sigma = 1. 39 + / - 0. 06 mag ( compared to m _ v ^ 0 = 23. 74 mag and sigma = 1. 44 mag from an earlier study using the same data by whitmore it et al. 1995 ). the gclf in five radial bins is found to be statistically the same at all points, showing no clear evidence of dynamical destruction processes based on the luminosity function ( lf ), in contradiction to the claim by gnedin ( 1997 ). similarly, there is no obvious correlation between the half light radius of the clusters and the galactocentric distance. the core radius of the globular cluster density distribution is r _ c = 56 ' ', considerably larger than the core of the stellar component ( r _ c = 6. 8 ' ' ). the mean color of the cluster candidates is v - i = 1. 09 mag which corresponds to an average metallicity of fe / h = - 0. 74 dex. the color distribution is bimodal everywhere, with a blue peak at v - i = 0. 95 mag and a red peak at v - i = 1. 20 mag. the red population is only 0. 1 magnitude bluer than the underlying galaxy, indicating that these clusters formed late in the metal enrichment history of the galaxy and were possibly created in a burst of star / cluster formation 3 - 6 gyr after the blue population. we also find that both the red and the blue cluster distributions have a more elliptical shape ( hubble type e3. 5 ) than the nearly spherical galaxy. the average half light radius of the clusters is ~ 2. 5 pc which is comparable to the 3 pc average effective radius of the milky way clusters, though the red candidates are ~ 20 % smaller than the blue ones. | arxiv:astro-ph/9812199 |
two - sided platforms rely on their recommendation algorithms to help visitors successfully find a match. however, on platforms such as volunteermatch ( vm ) - - which has facilitated millions of connections between volunteers and nonprofits - - a sizable fraction of website traffic arrives directly to a nonprofit ' s volunteering page via an external link, thus bypassing the platform ' s recommendation algorithm. we study how such platforms should account for this external traffic in the design of their recommendation algorithms, given the goal of maximizing successful matches. we model the platform ' s problem as a special case of online matching, where ( using vm terminology ) volunteers arrive sequentially and probabilistically match with one opportunity, each of which has finite need for volunteers. in our framework, external traffic is interested only in their targeted opportunity ; by contrast, internal traffic may be interested in many opportunities, and the platform ' s online algorithm selects which opportunity to recommend. in evaluating different algorithms, we parameterize the competitive ratio based on the amount of external traffic. after demonstrating the shortcomings of a commonly - used algorithm that is optimal in the absence of external traffic, we propose a new algorithm - - adaptive capacity ( ac ) - - which accounts for matches differently based on whether they originate from internal or external traffic. we provide a lower bound on ac ' s competitive ratio that is increasing in the amount of external traffic and that is close to ( and, in some regimes, exactly matches ) the parameterized upper bound we establish on the competitive ratio of any online algorithm. we complement our theoretical results with a numerical study motivated by vm data that demonstrates the strong performance of ac and furthers our understanding of the difference between ac and other commonly - used algorithms. | arxiv:2203.15037 |
this paper is devoted to a general min - max characterization of the eigenvalues in a gap of the essential spectrum of a self - adjoint unbounded operator. we prove an abstract theorem, then we apply it to the case of dirac operators with a coulomb - like potential. the result is optimal for the coulomb potential. an erratum is appended at the end of the tex. | arxiv:2206.06327 |
this thesis presents a way to apply this theorem of gabber to a large portion of voevodsky ' s work in order to lift the assumption that resolution of singularities holds. this gives unconditional versions of many of his and others ' theorems provided we work z [ 1 / p ] linearly, where p is the exponential characteristic of the base field. one example of the many applications we give is a partial answer to a 1980 conjecture of weibel. another is the removal of the hypothesis of resolution of singularities from a result of suslin that compares bloch ' s higher chow groups and etale cohomology. voevodsky ' s main tool in applying resolution of singularities is the cdh topology. we enlarge it slightly in order to apply this theorem of gabber, presenting in this thesis a topology that we name the ldh topology, where l is a prime. we compare the cdh and ldh topologies using the concept of a " presheaf with traces ", providing conditions under which the cdh and ldh sheafifications of a presheaf agree, as well as its cdh and ldh cohomologies. as far as applying resolution of singularities to motives goes, voevodsky ' s most important theorem can be rephrased as a cdh descent condition, and we are led to ask for conditions under which certain objects in the morel - voevodsky stable homotopy category satisfy ldh descent. in order to compare cdh and ldh descent, we generalise the notion of a " presheaf with traces " to the concept of an " object with traces ". we build on some results of pelaez on the functoriality of the slice filtration to show that this concept of an " object with traces " interacts well enough with the slice filtration to provide the ldh descent that we need. | arxiv:1305.5349 |
in this paper we construct all the primitive idempotents of the restricted quantum group $ \ overline { u } _ q ( sl _ 2 ) $ and also determine the multiplication rules among a basis given by the action of generators of $ \ bar { u } _ q ( sl _ 2 ) $ to the idempotents. by using this result we construct a basis of the space of symmetric linear functions of $ \ overline { u } _ q ( sl _ 2 ) $ and determine the decomposition of the integral of the dual of $ \ overline { u } _ q ( sl _ 2 ) $ twisted by the balancing element to the basis of the space of symmetric linear functions. | arxiv:0807.0052 |
atpboost is a system for solving sets of large - theory problems by interleaving atp runs with state - of - the - art machine learning of premise selection from the proofs. unlike many previous approaches that use multi - label setting, the learning is implemented as binary classification that estimates the pairwise - relevance of ( theorem, premise ) pairs. atpboost uses for this the xgboost gradient boosting algorithm, which is fast and has state - of - the - art performance on many tasks. learning in the binary setting however requires negative examples, which is nontrivial due to many alternative proofs. we discuss and implement several solutions in the context of the atp / ml feedback loop, and show that atpboost with such methods significantly outperforms the k - nearest neighbors multilabel classifier. | arxiv:1802.03375 |
in recent years, the development of the internet of things ( iot ) has prompted the search for na - range current references that are simultaneously constrained to a small area and robust to process, voltage and temperature variations. yet, such references have remained elusive, as existing architectures fail to reach a low temperature coefficient ( tc ) while minimizing silicon area. in this work, we propose a na - range constant - with - temperature ( cwt ) peaking current reference, in which a resistor is biased by the threshold voltage difference between two transistors in weak inversion. this bias voltage is lower than in conventional architectures to cut down the silicon area occupied by the resistor and is obtained by forward body biasing one of the two transistors with an ultra - low - power voltage reference so as to reduce its threshold voltage. in addition, the proposed reference includes a circuit to suppress the leakage of parasitic diodes at high temperature, and two simple trimming mechanisms for the reference current and its tc. as the proposed design relies on the body effect, it has been validated in both 0. 11 - $ \ mu $ m bulk and 22 - nm fully - depleted silicon - on - insulator, to demonstrate feasibility across different technology types. in post - layout simulation, the 0. 11 - $ \ mu $ m design generates a 5 - na current with a 65 - ppm / { \ deg } c tc and a 2. 84 - % / v line sensitivity ( ls ), while in measurement, the 22 - nm design achieves a 1. 5 - na current with an 89 - ppm / { \ deg } c tc and a 0. 51 - % / v ls. as a result of the low resistor bias voltage, the proposed references occupy a silicon area of 0. 00954 mm $ ^ 2 $ in 0. 11 $ \ mu $ m ( resp. 0. 00214 mm $ ^ 2 $ in 22 nm ) at least 1. 8 $ \ times $ ( resp. 8. 2 $ \ times $ ) smaller than fabricated na - range cwt references, but with a tc improved by 6. 1 $ \ times $ ( resp. 4. 4 $ \ times $ ). | arxiv:2406.09104 |
plant diseases significantly impact agricultural productivity, resulting in economic losses and food insecurity. prompt and accurate detection is crucial for the efficient management and mitigation of plant diseases. this study investigates advanced techniques in plant disease detection, emphasizing the integration of image processing, machine learning, deep learning methods, and mobile technologies. high - resolution images of plant leaves were captured and analyzed using convolutional neural networks ( cnns ) to detect symptoms of various diseases, such as blight, mildew, and rust. this study explores 14 classes of plants and diagnoses 26 unique plant diseases. we focus on common diseases affecting various crops. the model was trained on a diverse dataset encompassing multiple crops and disease types, achieving 98. 14 % accuracy in disease diagnosis. finally integrated this model into mobile apps for real - time disease diagnosis. | arxiv:2408.15289 |
we study the homogenized energy densities of periodic ferromagnetic ising systems. we prove that, for finite range interactions, the homogenized energy density, identifying the effective limit, is crystalline, i. e. its wulff crystal is a polytope, for which we can ( exponentially ) bound the number of vertices. this is achieved by deriving a dual representation of the energy density through a finite cell formula. this formula also allows easy numerical computations : we show a few experiments where we compute periodic patterns which minimize the anisotropy of the surface tension. | arxiv:2106.08111 |
nearly 900 million people live in low - lying coastal zones around the world and bear the brunt of impacts from more frequent and severe hurricanes and storm surges. oceanographers simulate ocean current circulation along the coasts to develop early warning systems that save lives and prevent loss and damage to property from coastal hazards. traditionally, such simulations are conducted using coastal ocean circulation models such as the regional ocean modeling system ( roms ), which usually runs on an hpc cluster with multiple cpu cores. however, the process is time - consuming and energy expensive. while coarse - grained roms simulations offer faster alternatives, they sacrifice detail and accuracy, particularly in complex coastal environments. recent advances in deep learning and gpu architecture have enabled the development of faster ai ( neural network ) surrogates. this paper introduces an ai surrogate based on a 4d swin transformer to simulate coastal tidal wave propagation in an estuary for both hindcast and forecast ( up to 12 days ). our approach not only accelerates simulations but also incorporates a physics - based constraint to detect and correct inaccurate results, ensuring reliability while minimizing manual intervention. we develop a fully gpu - accelerated workflow, optimizing the model training and inference pipeline on nvidia dgx - 2 a100 gpus. our experiments demonstrate that our ai surrogate reduces the time cost of 12 - day forecasting of traditional roms simulations from 9, 908 seconds ( on 512 cpu cores ) to 22 seconds ( on one a100 gpu ), achieving over 450 $ \ times $ speedup while maintaining high - quality simulation results. this work contributes to oceanographic modeling by offering a fast, accurate, and physically consistent alternative to traditional simulation models, particularly for real - time forecasting in rapid disaster response. | arxiv:2410.14952 |
the analysis of graphs has become increasingly important to a wide range of applications. graph analysis presents a number of unique challenges in the areas of ( 1 ) software complexity, ( 2 ) data complexity, ( 3 ) security, ( 4 ) mathematical complexity, ( 5 ) theoretical analysis, ( 6 ) serial performance, and ( 7 ) parallel performance. implementing graph algorithms using matrix - based approaches provides a number of promising solutions to these challenges. the graphblas standard ( istc - bigdata. org / graphblas ) is being developed to bring the potential of matrix based graph algorithms to the broadest possible audience. the graphblas mathematically defines a core set of matrix - based graph operations that can be used to implement a wide class of graph algorithms in a wide range of programming environments. this paper provides an introduction to the graphblas and describes how the graphblas can be used to address many of the challenges associated with analysis of graphs. | arxiv:1504.01039 |
online platforms can be divided into information - oriented and social - oriented domains. the former refers to forums or e - commerce sites that emphasize user - item interactions, like trip. com and amazon ; whereas the latter refers to social networking services ( snss ) that have rich user - user connections, such as facebook and twitter. despite their heterogeneity, these two domains can be bridged by a few overlapping users, dubbed as bridge users. in this work, we address the problem of cross - domain social recommendation, i. e., recommending relevant items of information domains to potential users of social networks. to our knowledge, this is a new problem that has rarely been studied before. existing cross - domain recommender systems are unsuitable for this task since they have either focused on homogeneous information domains or assumed that users are fully overlapped. towards this end, we present a novel neural social collaborative ranking ( nscr ) approach, which seamlessly sews up the user - item interactions in information domains and user - user connections in snss. in the information domain part, the attributes of users and items are leveraged to strengthen the embedding learning of users and items. in the sns part, the embeddings of bridge users are propagated to learn the embeddings of other non - bridge users. extensive experiments on two real - world datasets demonstrate the effectiveness and rationality of our nscr method. | arxiv:1706.03205 |
a spatial curve dynamical model framework is adopted for functional prediction of counts in a spatiotemporal log - gaussian cox process model. our spatial functional estimation approach handles both wavelet - based heterogeneity analysis in time, and spectral analysis in space. specifically, model fitting is achieved by minimising the information divergence or relative entropy between the multiscale model underlying the data and the corresponding candidates in the spatial spectral domain. a simulation study is carried out within the family of log - gaussian spatial autoregressive l2 - valued processes ( sarl2 processes ) to illustrate the asymptotic properties of the proposed spatial functional estimators. we apply our modelling strategy to spatiotemporal prediction of respiratory disease mortality. | arxiv:2010.03827 |
we investigate the many - body landau - zener ( lz ) process in a two - site bose - hubbard model driven by a time - periodic field. we find that the driving field may induce sideband transitions in addition to the main lz transitions. these photon - induced sideband transitions are a signature of the photon - assisted tunneling in our many - body lz process. in the strong interaction regime, we develop an analytical theory for understanding the sideband transitions, which is confirmed by our numerical simulation. furthermore, we discuss the quantization of the driving field. in the effective model of the quantized driving field, the sideband transitions can be understood as the lz transitions between states of different " photon " numbers. | arxiv:1404.3792 |
initial - boundary value problems for integrable nonlinear partial differential equations have become tractable in recent years due to the development of so - called unified transform techniques. the main obstruction to applying these methods in practice is that calculation of the spectral transforms of the initial and boundary data requires knowledge of too many boundary conditions, more than are required make the problem well - posed. the elimination of the unknown boundary values is frequently addressed in the spectral domain via the so - called global relation, and types of boundary conditions for which the global relation can be solved are called \ emph { linearizable }. for the defocusing nonlinear schr \ " odinger equation, the global relation is only known to be explicitly solvable in rather restrictive situations, namely homogeneous boundary conditions of dirichlet, neumann, and robin ( mixed ) type. general nonhomogeneous boundary conditions are not known to be linearizable. in this paper, we propose an explicit approximation for the nonlinear dirichlet - to - neumann map supplied by the defocusing nonlinear schr \ " odinger equation and use it to provide approximate solutions of general nonhomogeneous boundary value problems for this equation posed as an initial - boundary value problem on the half - line. our method sidesteps entirely the solution of the global relation. the accuracy of our method is proven in the semiclassical limit, and we provide explicit asymptotics for the solution in the interior of the quarter - plane space - time domain. | arxiv:1406.7797 |
we study the stability of band preserving operators on banach lattices. to this end the notion of $ \ varepsilon $ - band preserving mapping is introduced. it is shown that, under quite general assumptions, a $ \ varepsilon $ - band preserving operator is in fact a small perturbation of a band preserving one. however, a counterexample can be produced in some circumstances. some results on automatic continuity of $ \ varepsilon $ - band preserving maps are also obtained. | arxiv:1610.02557 |
in this paper, we consider the r \ ' enyi entanglement asymmetry of excited states in the 1 + 1 dimensional free compact boson conformal field theory ( cft ) at equilibrium. we obtain a universal cft expression written by correlation functions for the charged moments via the replica trick. we provide detailed analytic computations of the second r \ ' enyi entanglement asymmetry in the free compact boson cft for excited states $ \ psi = v _ { \ beta } + v _ { - \ beta } $ and $ \ phi = v _ { \ beta } + j $ with $ v _ { \ beta } $ and $ j = i \ partial \ phi $ being the vertex operator and current operator respectively. we make numerical tests of the universal cft computations using the xx spin chain model. taking the non - hermite fake rdms into consideration, we propose an effective way to test them numerically, which can be applied to other excited states. the cft predictions are in perfect agreement with the exact numerical calculations. | arxiv:2310.15480 |
we study the compression of bundles of aligned macroscopic fibers with intrinsic shape disorder, as found in human hair and in many other natural and man - made systems. we show by a combination of experiments, numerical simulations and theory how the statistical properties of the shapes of the fibers control the collective mechanical behaviour of the bundles. this work paves the way for designing aligned fibrous matter with pre - required properties from large numbers of individual strands of selected geometry and rigidity. | arxiv:1809.10234 |
in 1964 erd \ h { o } s proved that $ ( 1 + \ oh { 1 } ) ) \ frac { \ eul \ ln ( 2 ) } { 4 } k ^ 2 2 ^ { k } $ edges are sufficient to build a $ k $ - graph which is not two colorable. to this day, it is not known whether there exist such $ k $ - graphs with smaller number of edges. erd \ h { o } s ' bound is consequence of the fact that a hypergraph with $ k ^ 2 / 2 $ vertices and $ m ( k ) = ( 1 + \ oh { 1 } ) \ frac { \ eul \ ln ( 2 ) } { 4 } k ^ 2 2 ^ { k } $ randomly chosen edges of size $ k $ is asymptotically almost surely not two colorable. our first main result implies that for any $ \ varepsilon > 0 $, any $ k $ - graph with $ ( 1 - \ varepsilon ) m ( k ) $ randomly and uniformly chosen edges is a. a. s. two colorable. the presented proof is an adaptation of the second moment method analogous to the developments of achlioptas and moore from 2002 who considered the problem with fixed size of edges and number of vertices tending to infinity. in the second part of the paper we consider the problem of algorithmic coloring of random $ k $ - graphs. we show that quite simple, and somewhat greedy procedure, a. a. s. finds a proper two coloring for random $ k $ - graphs on $ k ^ 2 / 2 $ vertices, with at most $ \ oh { k \ ln k \ cdot 2 ^ k } $ edges. that is of the same asymptotic order as the analogue of the \ emph { algorithmic barrier } defined by achlioptas and coja - oghlan in 2008, for the case of fixed $ k $. | arxiv:2102.12968 |
immiscible fluid displacement in porous media is fundamental for many environmental processes, including infiltration of water in soils, groundwater remediation, enhanced recovery of hydrocarbons and carbon geosequestration. microstructural heterogeneity, in particular of particle sizes, can significantly impact immiscible displacement. for instance, it may lead to unstable flow and preferential displacement patterns. we present a systematic, quantitative pore - scale study of the impact of spatial correlations in particle sizes on the drainage of a partially - wetting fluid. we perform pore - network simulations with varying flow rates and different degrees of spatial correlation, complemented with microfluidic experiments. simulated and experimental displacement patterns show that spatial correlation leads to more preferential invasion, with reduced trapping of the defending fluid, especially at low flow rates. numerically, we find that increasing the correlation length reduces the fluid - fluid interfacial area and the trapping of the defending fluid, and increases the invasion pattern asymmetry and selectivity. our experiments, conducted for low capillary numbers, support these findings. our results delineate the significant effect of spatial correlations on fluid displacement in porous media, of relevance to a wide range of natural and engineered processes. | arxiv:1901.00835 |
we study the size of large - scale motions in turbulent plane couette flows at moderate reynolds number up to $ re _ \ tau $ = 500. direct numerical simulation domains were as large as $ 100 \ pi \ delta \ times2 \ delta \ times5 \ pi \ delta $, where $ \ delta $ is half the distance between the walls. the results indicate that there are structures with streamwise extent, as measured by the wavelength, as long as 78 $ \ delta $ and at least 310 $ \ delta $ at $ re _ \ tau $ = 220 and 500, respectively. the presence of these very long structures is apparent in the spectra of all three velocity components and the reynolds stress. in dns using a smaller domain, the large structures are constrained, eliminating the streamwise variations present in the larger domain. effects of a smaller domain are also present in the mean velocity and the streamwise velocity variance in the outer flow. | arxiv:1706.09800 |
for a graph $ g $ and a hereditary property $ \ mathcal { p } $, let $ \ text { ex } ( g, \ mathcal { p } ) $ denote the maximum number of edges of a subgraph of $ g $ that belongs to $ \ mathcal { p } $. we prove that for every non - trivial hereditary property $ \ mathcal { p } $ such that $ l \ notin \ mathcal { p } $ for some bipartite graph $ l $ and for every fixed $ p \ in ( 0, 1 ) $ we have \ [ \ text { ex } ( g ( n, p ), \ mathcal { p } ) \ le n ^ { 2 - \ varepsilon } \ ] with high probability, for some constant $ \ varepsilon = \ varepsilon ( \ mathcal { p } ) > 0 $. this answers a question of alon, krivelevich and samotij. | arxiv:2405.09486 |
we perform a 1 - parameter family of self - adjoint extensions characterized by the parameter $ \ omega _ 0 $. this allows us to get generic boundary conditions for the quantum oscillator on $ n $ dimensional complex projective space ( $ \ mathbb { c } p ^ n $ ) and on its non - compact version i. e., lobachewski space ( $ \ mathcal l _ n $ ) in presence of constant magnetic field. as a result, we get a family of energy spectrums for the oscillator. in our formulation the already known result of this oscillator is also belong to the family. we have also obtained energy spectrum which preserve all the symmetry ( full hidden symmetry and rotational symmetry ) of the oscillator. the method of self - adjoint extensions have been discussed for conic oscillator in presence of constant magnetic field also. | arxiv:hep-th/0605153 |
the tango bundle t over p ^ 5 is proved to be the pull - back of the twisted cayley bundle c ( 1 ) via a map f : p ^ 5 - - > q _ 5 existing only in characteristic 2. the frobenius morphism f factorizes via such f. using f the cohomology of t is computed in terms of f ^ * ( c ), sym ^ 2 ( c ), c and the tensor product of s by c, while these are computed by applying borel - bott - weil theorem. by machine - aided computation the mimimal resolutions of c and t are given ; incidentally the matrix presenting the spinor bundle s over q _ 5 is shown. | arxiv:math/0111207 |
as modern scientific instruments generate vast amounts of data and the volume of information in the scientific literature continues to grow, machine learning ( ml ) has become an essential tool for organising, analysing, and interpreting these complex datasets. this paper explores the transformative role of ml in accelerating breakthroughs across a range of scientific disciplines. by presenting key examples - - such as brain mapping and exoplanet detection - - we demonstrate how ml is reshaping scientific research. we also explore different scenarios where different levels of knowledge of the underlying phenomenon are available, identifying strategies to overcome limitations and unlock the full potential of ml. despite its advances, the growing reliance on ml poses challenges for research applications and rigorous validation of discoveries. we argue that even with these challenges, ml is poised to disrupt traditional methodologies and advance the boundaries of knowledge by enabling researchers to tackle increasingly complex problems. thus, the scientific community can move beyond the necessary traditional oversimplifications to embrace the full complexity of natural systems, ultimately paving the way for interdisciplinary breakthroughs and innovative solutions to humanity ' s most pressing challenges. | arxiv:2405.04161 |
estimating heart rate is important for monitoring users in various situations. estimates based on facial videos are increasingly being researched because it makes it possible to monitor cardiac information in a non - invasive way and because the devices are simpler, requiring only cameras that capture the user ' s face. from these videos of the user ' s face, machine learning is able to estimate heart rate. this study investigates the benefits and challenges of using machine learning models to estimate heart rate from facial videos, through patents, datasets, and articles review. we searched derwent innovation, ieee xplore, scopus, and web of science knowledge bases and identified 7 patent filings, 11 datasets, and 20 articles on heart rate, photoplethysmography, or electrocardiogram data. in terms of patents, we note the advantages of inventions related to heart rate estimation, as described by the authors. in terms of datasets, we discovered that most of them are for academic purposes and with different signs and annotations that allow coverage for subjects other than heartbeat estimation. in terms of articles, we discovered techniques, such as extracting regions of interest for heart rate reading and using video magnification for small motion extraction, and models such as evm - cnn and vgg - 16, that extract the observed individual ' s heart rate, the best regions of interest for signal extraction and ways to process them. | arxiv:2202.08913 |
bachmann, takeyama and tasaka introduced a $ \ mathbb { q } $ - linear map $ \ phi $, which we call the symmetrization map in this paper, on the harmonic algebra $ \ mathfrak { h } ^ 1 $. they calculated $ \ phi ( w ) $ explicitly for an element $ w $ in $ \ mathfrak { h } ^ 1 $ related to the multiple zeta values of mordell - - tornheim type. in this paper, we introduce its $ t $ - adic generalization $ \ widehat { \ phi } $ and calculate $ \ widehat { \ phi } ( w ) $ for an element $ w $ in $ \ mathfrak { h } ^ 1 [ [ t ] ] $ constructed from the theory of $ 2 $ - colored rooted tree. | arxiv:2106.03682 |
ex - so - tic van der waals heterostructures take advantage of the electrically tunable layer polarization to swap proximity exchange and spin - orbit coupling in the electronically active region. perhaps the simplest example is bernal bilayer graphene ( bbg ) encapsulated by a layered magnet from one side and a strong spin - orbit material from the other. taking ws $ _ 2 $ / bbg / cr $ _ 2 $ ge $ _ 2 $ te $ _ 6 $ as a representative ex - so - tronic device, we employ realistic \ emph { ab initio } - inspired hamiltonians and effective electron - electron interactions to investigate the emergence of correlated phases within the random phase approximation. we find that for a given doping level, exchange and spin - orbit coupling induced stoner and intervalley coherence instabilities can be swapped, allowing to explore the full spectrum of correlated phases within a single device. | arxiv:2307.16025 |
we solve an asymptotic problem in the geometry of numbers, where we count the number of singular $ n \ times n $ matrices where row vectors are primitive and of length at most t. without the constraint of primitivity, the problem was solved by y. katznelson. we show that as $ t \ to \ infty $, the number is asymptotic to $ \ frac { ( n - 1 ) u _ n } { \ zeta ( n ) \ zeta ( n - 1 ) ^ { n } } t ^ { n ^ { 2 } - n } \ log ( t ) $ for $ n \ ge 3 $. the 3 - dimensional case is the most problematic and we need to invoke an equidistribution theorem due to w. schmidt. | arxiv:math/0305066 |
we give a new proof of a result of lazarev, that the dual of the circle $ s ^ 1 _ + $ in the category of spectra is equivalent to a strictly square - zero extension as an associative ring spectrum. as an application, we calculate the topological cyclic homology of $ ds ^ 1 $ and rule out a koszul - dual reformulation of the novikov conjecture. | arxiv:1610.06898 |
an inverse - free neural network model with mixed delays is proposed for solving the absolute value equation ( ave ) $ ax - | x | - b = 0 $, which includes an inverse - free neural network model with discrete delay as a special case. by using the lyapunov - krasovskii theory and the linear matrix inequality ( lmi ) method, the developed neural network models are proved to be exponentially convergent to the solution of the ave. compared with the existing neural network models for solving the ave, the proposed models feature the ability of solving a class of ave with $ \ | a ^ { - 1 } \ | > 1 $. numerical simulations are given to show the effectiveness of the two delayed neural network models. | arxiv:2310.10965 |
we show, that in contrast to the free electron model ( standard bcs model ), a particular gap in the spectrum of multiband superconductors opens at some distance from the fermi energy, if conduction band is composed of hybridized atomic orbitals of different symmetries. this gap has composite superconducting - hybridization origin, because it exists only if both the superconductivity and the hybridization between different kinds of orbitals are present. so for many classes of superconductors with multiorbital structure such spectrum changes should take place. these particular changes in the spectrum at some distance from the fermi level result in slow convergence of the spectral weight of the optical conductivity even in quite conventional superconductors with isotropic s - wave pairing mechanism. | arxiv:1701.05835 |
in this paper, we propose a verified numerical method for obtaining a sharp inclusion of the best constant for the embedding $ h _ { 0 } ^ { 1 } ( \ omega ) \ hookrightarrow l ^ { p } ( \ omega ) $ on bounded convex domain in $ \ mathbb { r } ^ { 2 } $. we estimate the best constant by computing the corresponding extremal function using a verified numerical computation. verified numerical inclusions of the best constant on a square domain are presented. | arxiv:1503.05468 |
we introduce nnetnav, a method for unsupervised interaction with websites that generates synthetic demonstrations for training browser agents. given any website, nnetnav produces these demonstrations by retroactively labeling action sequences from an exploration policy. most work on training browser agents has relied on expensive human supervision, and the limited prior work on such interaction - based techniques has failed to provide effective search through the exponentially large space of exploration. in contrast, nnetnav exploits the hierarchical structure of language instructions to make this search more tractable : complex instructions are typically decomposable into simpler sub - tasks, allowing nnetnav to automatically prune interaction episodes when an intermediate trajectory cannot be annotated with a meaningful sub - task. \ texttt { llama - 3. 1 - 8b } finetuned on 10k nnetnav self - generated demonstrations obtains over 16 \ % success rate on webarena, and 35 \ % on webvoyager, an improvement of 15pts and 31pts respectively over zero - shot \ texttt { llama - 3. 1 - 8b }, outperforming zero - shot gpt - 4 and reaching the state - of - the - art among unsupervised methods, for both benchmarks. | arxiv:2410.02907 |
in this paper we describe a remarkable new property of the self - adjoint extension w of the prolate spheroidal operator introduced in \ cite { college98 }, \ cite { cmbook }. the restriction of this operator to the interval j whose characteristic function commutes with it is well known, has discrete positive spectrum and is well understood. what we have discovered is that the restriction of w to the complement of j admits ( besides a replica of the above positive spectrum ) negative eigenvalues whose ultraviolet behavior reproduce that of the squares of zeros of the riemann zeta function. furthermore, their corresponding eigenfunctions belong to the sonin space. this feature fits with the proof \ cite { weilpos } of weil ' s positivity at the archimedean place, which uses the compression of the scaling action to the sonin space. as a byproduct we construct an isospectral family of dirac operators whose spectra have the same ultraviolet behavior as the zeros of the riemann zeta function. | arxiv:2112.05500 |
kac - moody groups over finite fields are finitely generated groups. most of them can naturally be viewed as irreducible lattices in products of two closed automorphism groups of non - positively curved twinned buildings : those are the most important ( but not the only ) examples of twin building lattices. we prove that these lattices are simple if and only if the corresponding buildings are ( irreducible and ) not of affine type ( i. e. they are not bruhat - tits buildings ). in fact, many of them are finitely presented and enjoy property ( t ). our arguments explain geometrically why simplicity fails to hold only for affine kac - moody groups. moreover we prove that a nontrivial continuous homomorphism from a completed kac - moody group is always proper. we also show that kac - moody lattices fulfill conditions implying strong superrigidity properties for isometric actions on non - positively curved metric spaces. most results apply to the general class of twin building lattices. | arxiv:math/0607664 |
we report on single - wall carbon nanotube ( swcnt ) specific $ ^ { 13 } $ c isotope enrichment. the high temperature annealing of isotope enriched fullerenes encapsulated in swcnts yields double - wall carbon nanotubes ( dwcnts ) with a high isotope enrichment of the inner wall. the vibrational spectra evidences that no carbon exchange occurs between the two walls. the method facilitates the identification of the raman signal of the outer and inner tubes. nuclear magnetic resonance proves the significant contrast of the isotope enriched swcnts as compared to other carbon phases, and provides information on the electronic properties of the small diameter inner tubes of the dwcnts. | arxiv:cond-mat/0406343 |
the linearized kerr metric is considered and put in some gauss coordinates which are further { \ em intrinsic } ones. the linear and angular 4 - momenta of this metric are calculated in these coordinates and the resulting value is just zero. thus, the global vanishing previously found for the schwarzschild metric remains linearly stable under slow rotational perturbations of this metric. | arxiv:1405.3187 |
synthetic perovskites with photovoltaic properties open a new era in solar photovoltaics. due to high optical absorption perovskite - based thin - film solar cells are usually considered as fully absorbing solar radiation on condition of ideal blooming. however, is it really so? the analysis of the literature data has shown that the absorbance of all photovoltaic pervoskites has the spectral hole at infrared frequencies where the solar radiation spectrum has a small local peak. this absorption dip results in the decrease of the optical efficiency of thin - film pervoskite solar cells by nearly 3 % and close the ways of utilise them at this range for any other applications. in our work we show that to cure this shortage is possible complementing the basic structure by an inexpensive plasmonic array. | arxiv:1601.06778 |
this note studies various ways of measuring the complexity of primitive solutions to the equation $ a \, + \, b \, + \, c = 0 $ and conjectures relating them. we define the insulator $ \ mathcal i ( a, b, c ) $ of a primitive solution as the smallest positive integer $ \ mathcal i $ such that the primes dividing the product $ abc \ cdot \ mathcal i $ are exactly those below a given bound. we show that the strong xyz conjecture of lagarias and soundararajan implies there are only finitely many primitive solutions $ ( a, b, c ) $ with a given insulator. | arxiv:1401.6439 |
we investigate a routing game that allows for the creation of coalitions, within the framework of cooperative game theory. specifically, we describe the cost of each coalition as its maximin value. this represents the performance that the coalition can guarantee itself, under any ( including worst ) conditions. we then investigate fundamental solution concepts of the considered cooperative game, namely the core and a variant of the min - max fair nucleolus. we consider two types of routing games based on the agents ' performance objectives, namely bottleneck routing games and additive routing games. for bottleneck games we establish that the core includes all system - optimal flow profiles and that the nucleolus is system - optimal or disadvantageous for the smallest agent in the system. moreover, we describe an interesting set of scenarios for which the nucleolus is always system - optimal. for additive games, we focus on the fundamental load balancing game of routing over parallel links. we establish that, in contrary to bottleneck games, not all system - optimal flow profiles lie in the core. however, we describe a specific system - optimal flow profile that does lie in the core and, under assumptions of symmetry, is equal to the nucleolus. | arxiv:1310.3487 |
visual reinforcement learning ( rl ) has made significant progress in recent years, but the choice of visual feature extractor remains a crucial design decision. this paper compares the performance of rl algorithms that train a convolutional neural network ( cnn ) from scratch with those that utilize pre - trained visual representations ( pvrs ). we evaluate the dormant ratio minimization ( drm ) algorithm, a state - of - the - art visual rl method, against three pvrs : resnet18, dinov2, and visual cortex ( vc ). we use the metaworld push - v2 and drawer - open - v2 tasks for our comparison. our results show that the choice of training from scratch compared to using pvrs for maximising performance is task - dependent, but pvrs offer advantages in terms of reduced replay buffer size and faster training times. we also identify a strong correlation between the dormant ratio and model performance, highlighting the importance of exploration in visual rl. our study provides insights into the trade - offs between training from scratch and using pvrs, informing the design of future visual rl algorithms. | arxiv:2407.17238 |
injection - based testing while refactoring is a pattern that minimizes the need for manual editing when altering the behaviour of a code base. neither does it rely on a compilation or a linking process nor does it make assumptions on the structure of the code. thus, it can be particularly useful for refactoring code that has been written in scripting languages, and specifically targets the research and engineering context. we describe the pattern and propose a set of functions for its application. the applicability of code injection for refactoring is highlighted via specific examples for deriving unit and integration tests. finally, we comment on the customizing of the pattern and give practical advice for its implementation. | arxiv:2203.14659 |
we present a theory of the imprinting of the electron spin coherence and population in an n - doped semiconductor which forms a junction with a ferromagnet. the reflection of non - equilibrium semiconductor electrons at the interface provides a mechanism to manipulate the spin polarization vector. in the case of unpolarized excitation, this ballistic effect produces spontaneous electron spin coherence and nuclear polarization in the semiconductor, as recently observed by time - resolved faraday rotation experiments. we investigate the dependence of the spin reflection on the schottky barrier height and the doping concentration in the semiconductor and suggest control mechanisms for possible device applications. | arxiv:cond-mat/0203285 |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.