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in this paper, we analyze the gaussian x channel in the mixed interference regime. in this regime, multiple access transmission to one of the receivers is shown to be close to optimal in terms of sum rate. three upper bounds are derived for the sum capacity in the mixed interference regime, and the subregions where each of these bounds dominate the others are identified. the genie - aided sum capacity upper bounds derived also show that the gap between sum capacity and the sum rate of the multiple access transmission scheme is small for a significant part of the mixed interference region. for any \ delta > 0, the region where multiple access transmission to one of the receivers is within \ delta from sum capacity is determined. | arxiv:1505.06317 |
while several matrix factorization ( mf ) and tensor factorization ( tf ) models have been proposed for knowledge base ( kb ) inference, they have rarely been compared across various datasets. is there a single model that performs well across datasets? if not, what characteristics of a dataset determine the performance of mf and tf models? is there a joint tf + mf model that performs robustly on all datasets? we perform an extensive evaluation to compare popular kb inference models across popular datasets in the literature. in addition to answering the questions above, we remove a limitation in the standard evaluation protocol for mf models, propose an extension to mf models so that they can better handle out - of - vocabulary ( oov ) entity pairs, and develop a novel combination of tf and mf models. we also analyze and explain the results based on models and dataset characteristics. our best model is robust, and obtains strong results across all datasets. | arxiv:1706.00637 |
we present a novel variational generative adversarial network ( vgan ) based on wasserstein loss to learn a latent representation from a face image that is invariant to identity but preserves head - pose information. this facilitates synthesis of a realistic face image with the same head pose as a given input image, but with a different identity. one application of this network is in privacy - sensitive scenarios ; after identity replacement in an image, utility, such as head pose, can still be recovered. extensive experimental validation on synthetic and real human - face image datasets performed under 3 threat scenarios confirms the ability of the proposed network to preserve head pose of the input image, mask the input identity, and synthesize a good - quality realistic face image of a desired identity. we also show that our network can be used to perform pose - preserving identity morphing and identity - preserving pose morphing. the proposed method improves over a recent state - of - the - art method in terms of quantitative metrics as well as synthesized image quality. | arxiv:2003.00641 |
visual language models ( vlms ) have demonstrated impressive capabilities in visual grounding tasks. however, their effectiveness in the medical domain, particularly for abnormality detection and localization within medical images, remains underexplored. a major challenge is the complex and abstract nature of medical terminology, which makes it difficult to directly associate pathological anomaly terms with their corresponding visual features. in this work, we introduce a novel approach to enhance vlm performance in medical abnormality detection and localization by leveraging decomposed medical knowledge. instead of directly prompting models to recognize specific abnormalities, we focus on breaking down medical concepts into fundamental attributes and common visual patterns. this strategy promotes a stronger alignment between textual descriptions and visual features, improving both the recognition and localization of abnormalities in medical images. we evaluate our method on the 0. 23b florence - 2 base model and demonstrate that it achieves comparable performance in abnormality grounding to significantly larger 7b llava - based medical vlms, despite being trained on only 1. 5 % of the data used for such models. experimental results also demonstrate the effectiveness of our approach in both known and previously unseen abnormalities, suggesting its strong generalization capabilities. | arxiv:2503.03278 |
this chapter investigates some mechanisms behind pattern formation driven by competitive - only or repelling interactions, and explores how these patterns are influenced by different types of particle movement. despite competition and repulsion are both anti - crowding interactions, collective effects may lead to clusters of individuals, which can arrange periodically. through the analysis of two models, it provides insights into the similarities and differences in the patterns formed and underlines the role of movement in shaping the spatial distribution of biological populations. | arxiv:2503.02486 |
we study the decay of a prepared state into non - flat continuum. we find that the survival probability $ p ( t ) $ might exhibit either stretched - exponential or power - law decay, depending on non - universal features of the model. still there is a universal characteristic time $ t _ 0 $ that does not depend on the functional form. it is only for a flat continuum that we get a robust exponential decay that is insensitive to the nature of the intra - continuum couplings. the analysis highlights the co - existence of perturbative and non - perturbative features in the local density of states, and the non - linear dependence of $ 1 / t _ 0 $ on the strength of the coupling. | arxiv:0905.4934 |
convection - diffusion equations provide the basis for describing heat and mass transfer phenomena as well as processes of continuum mechanics. to handle flows in porous media, the fundamental issue is to model correctly the convective transport of individual phases. moreover, for compressible media, the pressure equation itself is just a time - dependent convection - diffusion equation. for different problems, a convection - diffusion equation may be be written in various forms. the most popular formulation of convective transport employs the divergent ( conservative ) form. in some cases, the nondivergent ( characteristic ) form seems to be preferable. the so - called skew - symmetric form of convective transport operators that is the half - sum of the operators in the divergent and nondivergent forms is of great interest in some applications. here we discuss the basic classes of discretization in space : finite difference schemes on rectangular grids, approximations on general polyhedra ( the finite volume method ), and finite element procedures. the key properties of discrete operators are studied for convective and diffusive transport. we emphasize the problems of constructing approximations for convection and diffusion operators that satisfy the maximum principle at the discrete level - - - they are called monotone approximations. two - and three - level schemes are investigated for transient problems. unconditionally stable explicit - implicit schemes are developed for convection - diffusion problems. stability conditions are obtained both in finite - dimensional hilbert spaces and in banach spaces depending on the form in which the convection - diffusion equation is written. | arxiv:1208.5649 |
radiosensitizers can increase the local treatment efficacy under a relatively low and safe radiation dose, thereby facilitating tumor eradication and minimizing side effects. here, we report a new class of radiosensitizers that contain several gold ( au ) atoms embedded inside a peptide shell ( e. g., au10 - 12 ( sg ) 10 - 12 ) and can achieve ultrahigh tumor uptake ( 10. 86 suv at 24 h post injection ) and targeting specificity, efficient renal clearance, and high radiotherapy enhancement. | arxiv:1405.2635 |
an explicit reciprocal transformation between a 2 - component generalization of the camassa - holm equation, called the 2 - ch system, and the first negative flow of the akns hierarchy is established, this transformation enables one to obtain solutions of the 2 - ch system from those of the first negative flow of the akns hierarchy. interesting examples of peakon and multi - kink solutions of the 2 - ch system are presented. | arxiv:nlin/0501028 |
cross - sectional scanning tunneling microscopy ( x - stm ) is used to experimentally study the influence of isovalent bi atoms on the electronic structure of inp. we map the spatial pattern of the bi impurity state, which originates from bi atoms down to the sixth layer below the surface, in topographic, filled state x - stm images on the natural $ \ { 110 \ } $ cleavage planes. the bi impurity state has a highly anisotropic bowtie - like structure and extends over several lattice sites. these bi - induced charge redistributions extend along the $ \ left \ langle 110 \ right \ rangle $ directions, which define the bowtie - like structures we observe. local tight - binding calculations reproduce the experimentally observed spatial structure of the bi impurity state. in addition, the influence of the bi atoms on the electronic structure is investigated in scanning tunneling spectroscopy measurements. these measurements show that bi induces a resonant state in the valence band, which shifts the band edge towards higher energies. this is in good agreement to first principles calculations. furthermore, we show that the energetic position of the bi induced resonance and its influence on the onset of the valence band edge depend crucially on the position of the bi atoms relative to the cleavage plane. | arxiv:1906.01790 |
early diagnosis of alzheimer ' s disease plays a key role in understanding the degree of the patient ' s mental decline and determining preventive therapies. in this study, we introduce waveletbrain, a novel representation of the white and gray matter surfaces of the cortex. the proposed framework innovates by deriving localized shape information from a global harmonic representation, that can be used in large - scale population studies of surface data. results show that waveletbrain leads to statistically significant improvements in comparison to the shapedna representation in a variety of experiments including ( i ) classification of alzheimer ' s disease, normal aging, and mild cognitive impairment, ( ii ) sex classification and ( iii ) age prediction of subjects. we performed our analysis on 719 patients and 2, 876 surfaces. while this work focuses primarily on alzheimer ' s disease diagnosis, our proposed framework can be used to address general surface analysis problems in neuroscience. | arxiv:1906.06158 |
health or public health is an aspect of health services concerned with threats to the overall health of a community based on population health analysis. psychiatry is the branch of medicine concerned with the bio - psycho - social study of the etiology, diagnosis, treatment and prevention of cognitive, perceptual, emotional and behavioral disorders. related fields include psychotherapy and clinical psychology. = = = interdisciplinary fields = = = some interdisciplinary sub - specialties of medicine include : addiction medicine deals with the treatment of addiction. aerospace medicine deals with medical problems related to flying and space travel. biomedical engineering is a field dealing with the application of engineering principles to medical practice. clinical pharmacology is concerned with how systems of therapeutics interact with patients. conservation medicine studies the relationship between human and non - human animal health, and environmental conditions. also known as ecological medicine, environmental medicine, or medical geology. disaster medicine deals with medical aspects of emergency preparedness, disaster mitigation and management. diving medicine ( or hyperbaric medicine ) is the prevention and treatment of diving - related problems. evolutionary medicine is a perspective on medicine derived through applying evolutionary theory. forensic medicine deals with medical questions in legal context, such as determination of the time and cause of death, type of weapon used to inflict trauma, reconstruction of the facial features using remains of deceased ( skull ) thus aiding identification. gender - based medicine studies the biological and physiological differences between the human sexes and how that affects differences in disease. health informatics is a relatively recent field that deal with the application of computers and information technology to medicine. hospice and palliative medicine is a relatively modern branch of clinical medicine that deals with pain and symptom relief and emotional support in patients with terminal illnesses including cancer and heart failure. hospital medicine is the general medical care of hospitalized patients. physicians whose primary professional focus is hospital medicine are called hospitalists in the united states and canada. the term most responsible physician ( mrp ) or attending physician is also used interchangeably to describe this role. laser medicine involves the use of lasers in the diagnostics or treatment of various conditions. many other health science fields, e. g. dietetics medical ethics deals with ethical and moral principles that apply values and judgments to the practice of medicine. medical humanities includes the humanities ( literature, philosophy, ethics, history and religion ), social science ( anthropology, cultural studies, psychology, sociology ), and the arts ( literature, theater, film, and visual arts ) and their application to medical education and practice. nosokinetics | https://en.wikipedia.org/wiki/Medicine |
this paper introduces neuroute, a dynamic routing framework for software defined networks ( sdn ) entirely based on machine learning, specifically, neural networks. current sdn / openflow controllers use a default routing based on dijkstra algorithm for shortest paths, and provide apis to develop custom routing applications. neuroute is a controller - agnostic dynamic routing framework that ( i ) predicts traffic matrix in real time, ( ii ) uses a neural network to learn traffic characteristics and ( iii ) generates forwarding rules accordingly to optimize the network throughput. neuroute achieves the same results as the most efficient dynamic routing heuristic but in much less execution time. | arxiv:1709.06002 |
in this paper, we propose an efficient parallelization strategy for boundary element method ( bem ) solvers that perform the electromagnetic analysis of structures with lossy conductors. the proposed solver is accelerated with the adaptive integral method, can model both homogeneous and multilayered background media, and supports excitation via lumped ports or an incident field. unlike existing parallel bem solvers, we use a formulation that rigorously models the skin effect, which results in two coupled computational workloads. the external - problem workload models electromagnetic coupling between conductive objects, while the internal - problem workload describes field distributions within them. we propose a parallelization strategy that distributes these two workloads evenly over thousands of processing cores. the external - problem workload is balanced in the same manner as existing parallel solvers that employ approximate models for conductive objects. however, we assert that the internal - problem workload should be balanced by algorithms from scheduling theory. the parallel scalability of the proposed solver is tested on three different structures found in both integrated circuits and metasurfaces. the proposed parallelization strategy runs efficiently on distributed - memory computers with thousands of cpu cores and outperforms competing strategies derived from existing methods. | arxiv:2108.03991 |
the broaching that follows the surf - riding is a dangerous phenomenon that can lead to the capsizing of a vessel due to its violent yaw motion. most of the previous studies on surf - riding phenomena in irregular waves have been conducted by replacing irregular waves with regular waves. in contrast, this study provides suggestions on how to directly calculate nonlinear surge motion in irregular seas. in this study, the statistical aspects of the surf - riding phenomenon are first presented. then, under several approximations, we show how to calculate the probability density function theoretically. although the results obtained are based on strong approximations, it is found that the nonlinear surge oscillations in irregular following seas can be explained from a qualitative point of view. | arxiv:2401.05356 |
recent experiments on macroscopic quantum tunneling reveal a non - exponential decay of the number of atoms trapped in a quasibound state behind a potential barrier. through both experiment and theory, we demonstrate this non - exponential decay results from interactions between atoms. quantum tunneling of tens of thousands of 87 rb atoms in a bose - einstein condensate is modeled by a modified jeffreys - wentzel - kramers - brillouin model, taking into account the effective time - dependent barrier induced by the mean - field. three - dimensional gross - pitaevskii simulations corroborate a mean - field result when compared with experiments. however, with one - dimensional modeling using time - evolving block decimation, we present an effective renormalized mean - field theory that suggests many - body dynamics for which a bare mean - field theory may not apply. | arxiv:1705.04364 |
following gromov, a riemannian manifold is called area - extremal if any modification that increases scalar curvature must decrease the area of some tangent 2 - plane. we prove that large classes of compact 4 - manifolds, with or without boundary, with nonnegative sectional curvature are area - extremal. we also show that all regions of positive sectional curvature on 4 - manifolds are locally area - extremal. these results are obtained analyzing sections in the kernel of a twisted dirac operator constructed from pairs of metrics, and using the finsler - - thorpe trick for sectional curvature bounds in dimension 4. | arxiv:2205.00543 |
in recent years, some spectrum sensing algorithms using multiple antennas, such as the eigenvalue based detection ( ebd ), have attracted a lot of attention. in this paper, we are interested in deriving the asymptotic distributions of the test statistics of the ebd algorithms. two ebd algorithms using sample covariance matrices are considered : maximum eigenvalue detection ( med ) and condition number detection ( cnd ). the earlier studies usually assume that the number of antennas ( k ) and the number of samples ( n ) are both large, thus random matrix theory ( rmt ) can be used to derive the asymptotic distributions of the maximum and minimum eigenvalues of the sample covariance matrices. while assuming the number of antennas being large simplifies the derivations, in practice, the number of antennas equipped at a single secondary user is usually small, say 2 or 3, and once designed, this antenna number is fixed. thus in this paper, our objective is to derive the asymptotic distributions of the eigenvalues and condition numbers of the sample covariance matrices for any fixed k but large n, from which the probability of detection and probability of false alarm can be obtained. the proposed methodology can also be used to analyze the performance of other ebd algorithms. finally, computer simulations are presented to validate the accuracy of the derived results. | arxiv:1008.3056 |
for the discovery of regression relationships between y and a large set of p potential predictors x 1,..., x p, the flexible nonparametric nature of bart ( bayesian additive regression trees ) allows for a much richer set of possibilities than restrictive parametric approaches. however, subject matter considerations sometimes warrant a minimal assumption of monotonicity in at least some of the predictors. for such contexts, we introduce mbart, a constrained version of bart that can flexibly incorporate monotonicity in any predesignated subset of predictors using a multivariate basis of monotone trees, while avoiding the further confines of a full parametric form. for such monotone relationships, mbart provides ( i ) function estimates that are smoother and more interpretable, ( ii ) better out - of - sample predictive performance, and ( iii ) less post - data uncertainty. while many key aspects of the unconstrained bart model carry over directly to mbart, the introduction of monotonicity constraints necessitates a fundamental rethinking of how the model is implemented. in particular, the original bart markov chain monte carlo algorithm relied on a conditional conjugacy that is no longer available in a monotonically constrained space. various simulated and real examples demonstrate the wide ranging potential of mbart. | arxiv:1612.01619 |
task - specific instruction tuning enhances the performance of large language models ( llms ) on specialized tasks, yet efficiently selecting relevant data for this purpose remains a challenge. inspired by neural coactivation in the human brain, we propose a novel data selection method called nas, which leverages neuronal activation states as embeddings for samples in the feature space. extensive experiments show that nas outperforms classical data selection methods in terms of both effectiveness and robustness across different models, datasets, and selection ratios. | arxiv:2503.15573 |
we prove that, under reasonable conditions, odd co - dimension riemannian foliations cannot occur in positively curved manifolds. | arxiv:1602.01046 |
we discuss thermodynamics of fuzzy spheres in a matrix model on a pp - wave background. the exact free energy in the fuzzy sphere vacuum is computed in the \ mu - > \ infty limit for an arbitrary matrix size n. the trivial vacuum dominates the fuzzy sphere vacuum at low temperature while the fuzzy sphere vacuum is more stable than the trivial vacuum at sufficiently high temperature. our result supports that the fluctuations around the trivial vacuum would condense to form an irreducible fuzzy sphere above a certain temperature. | arxiv:hep-th/0401014 |
many research works have been carried out recently to find the optimal path in network routing. among them the evolutionary algorithms is an area where work is carried out extensively. we in this paper, have used pso for finding the optimal path and the concept of region based network is introduced along with the use of indirect encoding. a comparative study of genetic algorithm ( ga ) and particle swarm optimization ( pso ) is carried out, and it was found that pso performed better than ga. | arxiv:1107.1945 |
the results are presented of a study of the accuracy one may achieve at hera in measuring the strong coupling constant $ \ alpha _ s $ and the gluon distribution $ xg ( x, q ^ { 2 } ) $ using future data of the structure function $ f _ { 2 } ( x, q ^ { 2 } ) $ which are estimated to be accurate at the few % level over the full accessible kinematic region down to $ x \ simeq 10 ^ { - 5 } $ and up to $ q ^ { 2 } \ simeq 50000 gev ^ { 2 } $. the analysis includes simulated proton and deuteron data, and the effect of combining hera data with fixed target data is discussed. | arxiv:hep-ph/9609489 |
classes of the nonlinear schrodinger - type equations compatible with the galilei relativity principle are described. solutions of these equations satisfy the continuity equation. | arxiv:math-ph/0208016 |
we perform three - body model calculations for soft dipole excitations of the proton - rich borromean nucleus $ ^ { 17 } $ ne. to this end, we assume that $ ^ { 17 } $ ne takes the $ ^ { 15 } $ o + p + p structure, in which the two valence protons are excited from the $ 0 ^ + $ ground state configuration to $ 1 ^ - $ continuum states. we employ a density - dependent contact force for the nuclear part of the pairing interaction, and discretize the continuum states with the box boundary condition. we show by explicitly including the coulomb interaction between the valence protons that the coulomb repulsion does not significantly alter the e1 strength distribution. we point out that the effect of the coulomb repulsion in fact can be well simulated by renormalizing the nuclear pairing interaction. | arxiv:1109.2994 |
we examine for representative gaugino - higgsino mixing scenarios sneutrino - neutralino and sneutrino - chargino production in deep inelastic ep - scattering at the cm - energy of 1. 8 tev. the cross sections for sneutrino - chargino production are more than one order of magnitude bigger than those for sneutrino - squark production. also for zino - like neutralinos we find cross sections at least comparable to those for sneutrino - squark production. | arxiv:hep-ph/9408293 |
we investigate dirac fermions in the antifferomagnetic metallic state of iron - based superconduc - tors. deriving an effective hamiltonian for dirac fermions, we reveal that there exist two dirac cones carrying the same chirality, contrary to graphene, compensated by a fermi surface with a quadratic energy dispersion as a consequence of a non - trivial topological property inherent in the band structure. we also find that the presence of the dirac fermions gives the difference of sign - change temperatures between the hall coefficient and the thermopower. this is consistent with available experimental data. | arxiv:1003.5469 |
the detour between two points u and v ( on edges or vertices ) of an embedded planar graph whose edges are curves is the ratio between the shortest path in in the graph between u and v and their euclidean distance. the maximum detour over all pairs of points is called the geometric dilation. ebbers - baumann, gruene and klein have shown that every finite point set is contained in a planar graph whose geometric dilation is at most 1. 678, and some point sets require graphs with dilation at least pi / 2 = 1. 57... we prove a stronger lower bound of 1. 00000000001 * pi / 2 by relating graphs with small dilation to a problem of packing and covering the plane by circular disks. the proof relies on halving pairs, pairs of points dividing a given closed curve c in two parts of equal length, and their minimum and maximum distances h and h. additionally, we analyze curves of constant halving distance ( h = h ), examine the relation of h to other geometric quantities and prove some new dilation bounds. | arxiv:math/0407135 |
large language models ( llms ) have the potential of being useful tools that can automate tasks and assist humans. however, these models are more fluent in english and more aligned with western cultures, norms, and values. arabic - specific llms are being developed to better capture the nuances of the arabic language, as well as the views of the arabs. yet, arabs are sometimes assumed to share the same culture. in this position paper, i discuss the limitations of this assumption and provide preliminary thoughts for how to build systems that can better represent the cultural diversity within the arab world. the invalidity of the cultural homogeneity assumption might seem obvious, yet, it is widely adopted in developing multilingual and arabic - specific llms. i hope that this paper will encourage the nlp community to be considerate of the cultural diversity within various communities speaking the same language. | arxiv:2503.15003 |
the p - state clock model in two dimensions is a system of discrete rotors with a quasi - liquid phase in a region t1 < t < t2 for p > 4. we show that, for p > 4 and above a temperature teu, all macroscopic thermal averages, such as energy or magnetization, become identical to those of the continuous rotor ( p = \ infty ). this collapse of thermodynamic observables creates a regime of extended universality in the phase diagram and an emergent symmetry, not present in the hamiltonian. for p \ ge 8, the collapse starts in the quasi - liquid phase and makes the transition at t2 identical to the berezinskii - kosterlitz - thouless ( bkt ) transition of the con - tinuous rotor. for p \ le 6, the transition at t2 is below teu and no longer bkt. the results generate a comprehensive map of the critical properties at t1 and t2, and a range of experimental predictions, such as motion of magnetic domain walls, fab - rication of identical devices from different building blocks, and limits on macro - scopic distinguishability of different microscopic interactions. | arxiv:cond-mat/0511559 |
we discuss the experimental requirements for a mass hierarchy measurement for $ \ theta _ { 13 } = 0 $ using muon neutrino disappearance. we find that a specially optimized neutrino factory at $ l \ simeq 6 \, 000 \, \ mathrm { km } $ could do this measurement using extreme luminosities. in particular, we do not require charge identification for this purpose. in order to measure the mass hierarchy for more adequate luminosities, we explore the capabilities of low energy narrow band off - axis beams, which have relatively more events at low energies. we find that, in this case, the energy resolution of the detector quickly becomes the limiting factor of the measurement, and significantly affects the baseline optimization for determining the mass hierarchy. | arxiv:hep-ph/0509359 |
in this paper, a new strategy for a sub - element based shock capturing for discontinuous galerkin ( dg ) approximations is presented. the idea is to interpret a dg element as a collection of data and construct a hierarchy of low to high order discretizations on this set of data, including a first order finite volume scheme up to the full order dg scheme. the different dg discretizations are then blended according to sub - element troubled cell indicators, resulting in a final discretization that adaptively blends from low to high order within a single dg element. the goal is to retain as much high order accuracy as possible, even in simulations with very strong shocks, as e. g. presented in the sedov test. the framework retains the locality of the standard dg scheme and is hence well suited for a combination with adaptive mesh refinement and parallel computing. the numerical tests demonstrate the sub - element adaptive behavior of the new shock capturing approach and its high accuracy. | arxiv:2011.03338 |
in this paper, we propose an environment sensing - aided beam prediction model for smart factory that can be transferred from given environments to a new environment. in particular, we first design a pre - training model that predicts the optimal beam by sensing the present environmental information. when encountering a new environment, it generally requires collecting a large amount of new training data to retrain the model, whose cost severely impedes the application of the designed pre - training model. therefore, we next design a transfer learning strategy that fine - tunes the pre - trained model by limited labeled data of the new environment. simulation results show that when the pre - trained model is fine - tuned by 30 \ % of labeled data from the new environment, the top - 10 beam prediction accuracy reaches 94 \ %. moreover, compared with the way to completely re - training the prediction model, the amount of training data and the time cost of the proposed transfer learning strategy reduce 70 \ % and 75 \ % respectively. | arxiv:2405.15339 |
in this paper, we are interested in the spectral properties of the generalised principal eigenvalue of some nonlocal operator. that is, we look for the existence of some particular solution $ ( \ lambda, \ phi ) $ of a nonlocal operator. $ $ \ int _ { \ o } k ( x, y ) \ phi ( y ) \, dy + a ( x ) \ phi ( x ) = - \ lambda \ phi ( x ), $ $ where $ \ o \ subset \ r ^ n $ is an open bounded connected set, $ k $ a nonnegative kernel and $ a $ is continuous. we prove that for the generalised principal eigenvalue $ \ lambda _ p : = \ sup \ { \ lambda \ in \ r \, | \, \ exists \, \ phi \ in c ( \ o ), \ phi > 0 \ ; \ text { so that } \ ; \ oplb { \ phi } { \ o } + a ( x ) \ phi + \ lambda \ phi \ le 0 \ } $ there exists always a solution $ ( \ mu, \ lambda _ p ) $ of the problem in the space of signed measure. moreover $ \ mu $ a positive measure. when $ \ mu $ is absolutely continuous with respect to the lebesgue measure, $ \ mu = \ phi _ p ( x ) $ is called the principal eigenfunction associated to $ \ lambda _ p $. in some simple cases, we exhibit some explicit singular measures that are solutions of the spectral problem. | arxiv:1302.0949 |
deep neural networks have demonstrated superior performance in artificial intelligence applications, but the opaqueness of their inner working mechanism is one major drawback in their application. the prevailing unit - based interpretation is a statistical observation of stimulus - response data, which fails to show a detailed internal process of inherent mechanisms of neural networks. in this work, we analyze a convolutional neural network ( cnn ) trained in the classification task and present an algorithm to extract the diffusion pathways of individual pixels to identify the locations of pixels in an input image associated with object classes. the pathways allow us to test the causal components which are important for classification and the pathway - based representations are clearly distinguishable between categories. we find that the few largest pathways of an individual pixel from an image tend to cross the feature maps in each layer that is important for classification. and the large pathways of images of the same category are more consistent in their trends than those of different categories. we also apply the pathways to understanding adversarial attacks, object completion, and movement perception. further, the total number of pathways on feature maps in all layers can clearly discriminate the original, deformed, and target samples. | arxiv:2402.18132 |
we have witnessed different values of the hubble constant being found in the literature in the past years. albeit, early measurements often result in an $ h _ 0 $ much smaller than those from late - time ones, producing a statistically significant discrepancy, and giving rise to the so - called hubble tension. the trouble with the hubble constant is often treated as a cosmological problem. however, the hubble constant can be a laboratory to probe cosmology and particle physics models. in our work, we will investigate if the possibility of explaining the $ h _ 0 $ trouble using non - thermal dark matter production aided by phantom - like cosmology is consistent with the cosmic background radiation ( cmb ) and baryon acoustic oscillation ( bao ) data. we performed a full monte carlo simulation using cmb and bao datasets keeping the cosmological parameters $ \ omega _ b h ^ 2 $, $ \ omega _ c h ^ 2 $, $ 100 \ theta $, $ \ tau _ { opt } $, and $ w $ as priors and concluded that a non - thermal dark matter production aided by phantom - like cosmology yields at most $ h _ 0 = 70. 5 $ km s $ ^ { - 1 } $ mpc $ ^ { - 1 } $ which is consistent with some late - time measurements. however, if $ h _ 0 > 72 $ km s $ ^ { - 1 } $ mpc $ ^ { - 1 } $ as many late - time observations indicate, an alternative solution to the hubble trouble is needed. lastly, we limited the fraction of relativistic dark matter at the matter - radiation equality to be at most 1 \ %. | arxiv:2311.07420 |
software development includes diverse tasks such as implementing new features, analyzing requirements, and fixing bugs. being an expert in those tasks requires a certain set of skills, knowledge, and experience. several studies investigated individual aspects of software development expertise, but what is missing is a comprehensive theory. we present a first conceptual theory of software development expertise that is grounded in data from a mixed - methods survey with 335 software developers and in literature on expertise and expert performance. our theory currently focuses on programming, but already provides valuable insights for researchers, developers, and employers. the theory describes important properties of software development expertise and which factors foster or hinder its formation, including how developers ' performance may decline over time. moreover, our quantitative results show that developers ' expertise self - assessments are context - dependent and that experience is not necessarily related to expertise. | arxiv:1807.06087 |
we discuss the renormalization of gauge - invariant transverse - momentum dependent ( tmd ), i. e., unintegrated, parton distribution functions ( pdfs ) and carry out the calculation of their anomalous dimension at one loop. we show that in the light - cone gauge, tmd pdfs contain uv divergences that may be attributed to the renormalization effect on a cusp - like junction point of the gauge contours at infinity. in order to eliminate the anomalous dimension ensuing from this cusp, we propose to use in the definition of the tmd pdfs, a soft counter term in terms of a path - ordered phase factor along a particular cusped contour extending to transverse light - cone infinity and comprising light - like and transverse segments. we argue that this additional factor is analogous to the " intrinsic " coulomb phase factor found before in qed. | arxiv:0809.5235 |
we develop a physical model of the zodiacal cloud incorporating the real dust sources of asteroidal, cometary, and kuiperoidal origin. using the inferred distribution of the zodiacal dust, we compute its thermal emission and scattering at several wavelengths ( 1. 25, 5, and 20 $ \ mu $ m ) as a function of ngst location assumed to be at 1 au or 3 au. areas on the sky with a minimum of zodiacal light are determined. | arxiv:astro-ph/9910551 |
given a projective hyper - k \ " ahler manifold $ x $, we study the asymptotic base loci of big divisors on $ x $. we provide a numerical characterization of these loci and study how they vary while moving a big divisor class in the big cone, using the divisorial zariski decomposition, and the beauville - bogomolov - fujiki form. we determine the dual of the cones of $ k $ - ample divisors $ \ mathrm { amp } _ k ( x ) $, for any $ 1 \ leq k \ leq \ mathrm { dim } ( x ) $, answering affirmatively ( in the case of projective hyper - k \ " ahler manifolds ) a question asked by sam payne. we provide a decomposition for the effective cone $ \ mathrm { eff } ( x ) $ into chambers of mori - type, analogous to that for mori dream spaces into mori chambers. to conclude, we illustrate our results with several examples. | arxiv:2304.01773 |
harnessing the frequency dimension in integrated photonics offers key advantages in terms of scalability, noise resilience, parallelization and compatibility with telecom multiplexing techniques. integrated ring resonators have been used to generate frequency - entangled states through spontaneous four - wave - mixing. however, state - of - the - art integrated resonators are limited by trade - offs in size, number of frequency modes and spectral separation. we have developed silicon ring resonators with a foot - print below 0. 05 mm2 providing more than 70 frequency channels separated by 21 ghz. we exploit the narrow frequency separation to parallelize and independently control 34 single qubit - gates with off - the - shelf electro - optic devices. this allows to fully characterize 17 frequency - bin maximally - entangled qubit pairs by performing quantum state tomography. we demonstrate for the first time a fully connected 5 - user quantum network in the frequency domain. these results are a step towards a new generation of quantum circuits implemented with scalable silicon photonics technology, for applications in quantum computing and secure communications. | arxiv:2305.03457 |
radio telescopes with off - axis feeds, such as the ( e ) vla, suffer from " beam squint " in which the two orthogonal circular polarizations sampled have different pointing centers on the sky. its effects are weak near the beam center but become increasingly important towards the edge of the antenna power pattern where gains in the two polarizations at a given sky position are significantly different. this effect has limited vla measurements of circular polarization ( stokes v ) and introduced dynamic range limiting, wide - field artifacts in images made in stokes i. we present an adaptation of the visibility - based deconvolution clean method that can correct this defect " on the fly " while imaging, correcting as well the associated self - calibration. we present two examples of this technique using the procedure " squint " within the obit package which allows wide - field imaging in stokes v and reduced artifacts in stokes i. we discuss the residual errors in these examples as well as a scheme for future correction of some of these errors. this technique can be generalized to implement temporally - and spatially - variable corrections, such as pointing and cross - polarization leakage errors. | arxiv:0807.0026 |
the predominant use of wireless access networks is for media streaming applications, which are only gaining popularity as ever more devices become available for this purpose. however, current access networks treat all packets identically, and lack the agility to determine which clients are most in need of service at a given time. software reconfigurability of networking devices has seen wide adoption, and this in turn implies that agile control policies can be now instantiated on access networks. the goal of this work is to design, develop and demonstrate qflow, a learning approach to create a value chain from the application on one side, to algorithms operating over reconfigurable infrastructure on the other, so that applications are able to obtain necessary resources for optimal performance. using youtube video streaming as an example, we illustrate how qflow is able to adaptively provide such resources and attain a high qoe for all clients at a wireless access point. | arxiv:1901.00959 |
studies of a broad bandwidth, two - colour fel amplifier using one monoenergetic electron beam are presented. the two - colour fel interaction is achieved using a series of undulator modules alternately tuned to two well - separated resonant frequencies. using the broad bandwidth fel simulation code puffin, the electron beam is shown to bunch strongly and simultaneously at the two resonant frequencies. electron bunching components are also generated at the sum and difference of the resonant frequencies. | arxiv:1405.3144 |
we consider optimization of phase response curves for stochastic synchronization of non - interacting limit - cycle oscillators by common poisson impulsive signals. the optimal functional shape for sufficiently weak signals is sinusoidal, but can differ for stronger signals. by solving the euler - lagrange equation associated with the minimization of the lyapunov exponent characterizing synchronization efficiency, the optimal phase response curve is obtained. we show that the optimal shape mutates from a sinusoid to a sawtooth as the constraint on its squared amplitude is varied. | arxiv:1106.3425 |
potential line emission at 111 and 129 gev from 16 unassociated fermi - lat point sources has been reported recently by su & finkbeiner ( 2012c ). together with similar features seen by fermi in a region near the galactic centre, the evidence has been interpreted as the spectral signature of dark matter annihilation or internal bremsstrahlung. through a combination of supervised machine - learning algorithms and archival multiwavelength observations we find that 14 out of the 16 unassociated sources showing the line emission in the su & finkbeiner sample are most likely active galactic nuclei ( agn ). based on this new evidence, one must widen the range of possible solutions for the 100 - 140 gev excess to include a very distinct astrophysical explanation. while we cannot rule out a dark matter origin for the line emission in the galactic centre, we posit that if the detection in the su & finkbeiner sample is indeed real it might be related to accretion, bubble, or jet activity in nearby ( z < 0. 2 ) agn. alternatively, given the right conditions, the similarity could be due to a chance occurrence caused by extragalactic background light ( ebl ) absorption. or else one must concede that the features are an artefact of instrumental or calibration issues. | arxiv:1208.1693 |
we present a globally convergent method to accelerate density - based topology optimization using projection - based reduced - order models ( roms ) and trust - region methods. to accelerate topology optimization, we replace the large - scale finite element simulation, which dominates the computational cost, with roms that reduce the cost of objective function and gradient evaluations by orders of magnitude. to guarantee convergence, we first introduce a trust - region method that employs generalized trust - region constraints and prove it is globally convergent. we then devise a class of globally convergent rom - accelerated topology optimization methods informed by two theories : the aforementioned trust - region theory, which identifies the rom accuracy conditions required to guarantee the method converges to a critical point of the original topology optimization problem ; a posteriori error estimation theory for projection - based roms, which informs rom construction procedure to meet the accuracy conditions. this leads to trust - region methods that construct and update the rom on - the - fly during optimization ; the methods are guaranteed to converge to a critical point of the original, unreduced topology optimization problem, regardless of starting point. numerical experiments on three different structural topology optimization problems demonstrate the proposed reduced topology optimization methods accelerate convergence to the optimal design by up to an order of magnitude. | arxiv:2004.05756 |
turbulent convection plays a crucial role in many natural environments, ranging from earth ocean, mantle and outer core, to various astrophysical systems. for such flows with extremely strong thermal driving, an ultimate scaling was proposed for the heat flux and velocity. despite numerous experimental and numerical studies, a conclusive observation of the ultimate regime has not been reached yet. here we show that the ultimate scaling can be perfectly realized once the thermal boundary layer is fully decoupled from the viscous boundary layer and locates inside the turbulent bulk. the heat flux can be greatly enhanced by one order of magnitude. our results provide concrete evidences for the appearance of the ultimate state when the entire thermal boundary layer is embedded in the turbulent region, which is probably the case in many natural convection systems. | arxiv:2101.06651 |
{ m } m! ( n - 2m )! } }. } the number of fixed points of an involution on a finite set and its number of elements have the same parity. thus the number of fixed points of all the involutions on a given finite set have the same parity. in particular, every involution on an odd number of elements has at least one fixed point. this can be used to prove fermat ' s two squares theorem. = = involution throughout the fields of mathematics = = = = = real - valued functions = = = the graph of an involution ( on the real numbers ) is symmetric across the line y = x. this is due to the fact that the inverse of any general function will be its reflection over the line y = x. this can be seen by " swapping " x with y. if, in particular, the function is an involution, then its graph is its own reflection. some basic examples of involutions include the functions f ( x ) = a − x, f ( x ) = b x − a + a { \ displaystyle { \ begin { alignedat } { 1 } f ( x ) & = a - x \ ;, \ \ f ( x ) & = { \ frac { b } { x - a } } + a \ end { alignedat } } } besides, we can construct an involution by wrapping an involution g in a bijection h and its inverse ( h − 1 ∘ g ∘ h { \ displaystyle h ^ { - 1 } \ circ g \ circ h } ). for instance : f ( x ) = 1 − x 2 on [ 0 ; 1 ] ( g ( x ) = 1 − x and h ( x ) = x 2 ), f ( x ) = ln ( e x + 1 e x − 1 ) ( g ( x ) = x + 1 x − 1 = 2 x − 1 + 1 and h ( x ) = e x ) { \ displaystyle { \ begin { alignedat } { 2 } f ( x ) & = { \ sqrt { 1 - x ^ { 2 } } } \ quad { \ textrm { on } } \ ; [ 0 ; 1 ] & { \ bigl ( } g ( x ) = 1 - x \ quad { \ textrm { and } } \ quad h | https://en.wikipedia.org/wiki/Involution_(mathematics) |
thermal transport properties bear a pivotal role in influencing the performance of phase change memory ( pcm ) devices, in which the pcm operation involves fast and reversible phase change between amorphous and crystalline phases. in this paper, we present a systematic experimental and theoretical study on the thermal conductivity of gete at high temperatures involving fast change from amorphous to crystalline phase upon heating. modulated photothermal radiometry ( mptr ) is used to experimentally determine thermal conductivity of gete at high temperatures in both amorphous and crystalline phases. thermal boundary resistances are accurately taken into account for experimental consideration. to develop a concrete understanding of the underlying physical mechanism, rigorous and in - depth theoretical exercises are carried out. for this, first - principles density functional methods and linearized boltzmann transport equations ( lbte ) are employed using both direct and relaxation time based approach ( rta ) and compared with that of the phenomenological slack model. the amorphous phase experimental data has been described using the minimal thermal conductivity model with sufficient precision. the theoretical estimation involving direct solution and rta method are found to retrieve well the trend of the experimental thermal conductivity for crystalline gete at high temperatures despite being slightly overestimated and underestimated, respectively, compared to the experimental data. a rough estimate of vacancy contribution has been found to modify the direct solution in such a way that it agrees excellently with the experiment. umklapp scattering has been determined as the significant phonon - phonon scattering process. umklapp scattering parameter has been identified for gete for the whole temperature range which can uniquely determine and compare umklapp scattering processes for different materials | arxiv:2006.02625 |
we study the influence of cooperative effects such as superradiance and subradiance, on the scattering properties of dilute atomic gases. we show that cooperative effects lead to an effective potential between pairs of atoms that decays like $ 1 / r $. in the case of superradiance, this potential is attractive for close enough atoms and can be interpreted as a coherent mesoscopic effect. we consider a model of multiple scattering of a photon among superradiant pairs and calculate the elastic mean free path and the group velocity. we study first the case of a scalar wave which allows to obtain and to understand basic features of cooperative effects and multiple scattering. we then turn to the general problem of a vector wave. in both cases, we obtain qualitatively similar results and derive, for the case of a scalar wave, analytic expressions of the elastic mean free path and of the group velocity for an arbitrary ( near resonance ) detuning. | arxiv:0704.3522 |
we prove the existence of good log minimal models for dlt pairs of numerical log kodaira dimension 0. | arxiv:1101.1394 |
a number of optimal decision problems with uncertainty can be formulated into a stochastic optimal control framework. the least - squares monte carlo ( lsmc ) algorithm is a popular numerical method to approach solutions of such stochastic control problems as analytical solutions are not tractable in general. this paper generalizes the lsmc algorithm proposed in shen and weng ( 2017 ) to solve a wide class of stochastic optimal control models. our algorithm has three pillars : a construction of auxiliary stochastic control model, an artificial simulation of the post - action value of state process, and a shape - preserving sieve estimation method which equip the algorithm with a number of merits including bypassing forward simulation and control randomization, evading extrapolating the value function, and alleviating computational burden of the tuning parameter selection. the efficacy of the algorithm is corroborated by an application to pricing equity - linked insurance products. | arxiv:1901.06715 |
standard bayesian inference is known to be sensitive to model misspecification, leading to unreliable uncertainty quantification and poor predictive performance. however, finding generally applicable and computationally feasible methods for robust bayesian inference under misspecification has proven to be a difficult challenge. an intriguing, easy - to - use, and widely applicable approach is to use bagging on the bayesian posterior ( " bayesbag " ) ; that is, to use the average of posterior distributions conditioned on bootstrapped datasets. in this paper, we develop the asymptotic theory of bayesbag, propose a model - data mismatch index for model criticism using bayesbag, and empirically validate our theory and methodology on synthetic and real - world data in linear regression, sparse logistic regression, and a hierarchical mixed effects model. we find that in the presence of significant misspecification, bayesbag yields more reproducible inferences and has better predictive accuracy than the standard bayesian posterior ; on the other hand, when the model is correctly specified, bayesbag produces superior or equally good results. overall, our results demonstrate that bayesbag combines the attractive modeling features of standard bayesian inference with the distributional robustness properties of frequentist methods, providing benefits over both bayes alone and the bootstrap alone. | arxiv:1912.07104 |
we consider kalman filtering problems when the observations are intermittently erased or lost. it was known that the estimates are mean - square unstable when the erasure probability is larger than a certain critical value, and stable otherwise. but the characterization of the critical erasure probability has been open for years. we introduce a new concept of \ textit { eigenvalue cycles } which captures periodicity of systems, and characterize the critical erasure probability based on this. it is also proved that eigenvalue cycles can be easily broken if the original physical system is considered to be continuous - time - - - randomly - dithered nonuniform sampling of the observations makes the critical erasure probability almost surely $ \ frac { 1 } { | \ lambda _ { max } | ^ 2 } $. | arxiv:1308.6107 |
in the $ ab _ 4q _ 8 $ lacunar spinels, the electronic structure is described on the basis of inter - and intra - cluster interactions of tetrahedral $ b _ 4 $ clusters, and tuning these can lead to myriad fascinating electronic and magnetic ground states. in this work, we employ magnetic measurements, synchrotron x - ray and neutron scattering, and first - principles electronic structure calculations to examine the coupling between structural and magnetic phase evolution in gamo $ _ 4 $ se $ _ 8 $, including the emergence of a skyrmionic regime in the magnetic phase diagram. we show that the competition between two distinct jahn - teller distortions of the room temperature cubic $ f \ overline { 4 } 3m $ structure leads to the coexistence of the ground state $ r3m $ phase and a metastable $ imm2 $ phase. the magnetic properties of these two phases are computationally shown to be very different, with the $ imm2 $ phase exhibiting uniaxial ferromagnetism and the $ r3m $ phase hosting a complex magnetic phase diagram including equilibrium n \ ' eel - - type skyrmions stable from nearly $ t $ = 28 k down to $ t $ = 2 k, the lowest measured temperature. the large change in magnetic behavior induced by a small structural distortion reveals that gamo $ _ 4 $ se $ _ 8 $ is an exciting candidate material for tuning unconventional magnetic properties $ via $ mechanical means. | arxiv:2005.06662 |
in - plane torque measurements were performed on heavy fermion cecoin $ _ 5 $ single crystals in the temperature $ t $ range 1. 8 k $ \ leq t \ leq 10 $ k and applied magnetic field $ h $ up to 14 t. the normal - state torque is given by $ \ tau _ n \ propto h ^ 4 ( 1 + t / t _ k ) ^ { - 1 } \ sin 4 \ phi $. the reversible part of the mixed - state torque, obtained after subtracting the corresponding normal state torque, shows also a four - fold symmetry. in addition, sharp peaks are present in the irreversible torque at angles of $ \ pi / $ 4, 3 $ \ pi $ / 4, 5 $ \ pi $ / 4, 7 $ \ pi $ / 4, etc. both the four - fold symmetry in the reversible torque and the sharp peaks in the irreversible torque of the mixed state imply $ d _ { xy } $ symmetry of the superconducting order parameter. the field and temperature dependences of the reversible mixed - state torque provide further evidence for $ d _ { xy } $ wave symmetry. the four - fold symmetry in the normal state has a different origin since it has different field and temperature dependences than the one in the mixed state. the possible reasons of the normal state four - fold symmetry are discussed. | arxiv:0709.3771 |
the problem of anomalously high levels of flicker noise observed in the normal state of the high - temperature superconductors is addressed. it is argued that the anomaly is the result of incorrect normalization of the power spectra according to the hooge formula. a careful analysis of the available experimental data is given, which shows that the scaling of the spectral power with sample size is essentially different from the inverse proportionality. it is demonstrated that the measured spectra obey the law given by the recently proposed quantum theory of fundamental flicker noise. | arxiv:0904.4919 |
let $ r $ be a ring. in this paper, we study the characterization of cosilting modules and establish a relation between cosilting modules and cotilting objects in a grothendieck category. we proved that each cosilting right $ r $ - module $ t $ can be described as a cotilting object in $ \ sigma [ r / i ] $, where $ i $ is a right ideal of $ r $ determined by $ t $ and $ \ sigma [ r / i ] $ is the full subcategory of right $ r $ - modules, consisting of submodules of $ r / i $ - generated modules. conversely, under some suitable conditions, if $ t $ is a cotilting object in $ \ sigma [ r / i ] $, then $ t $ is cosilting. | arxiv:2103.05298 |
resonant intermediate states have been proposed to increase the efficiency of entangled two - photon absorption ( etpa ). although resonance - enhanced etpa ( r - etpa ) has been demonstrated in atomic systems using bright squeezed vacuum, it has not been studied in organic molecules. we investigate for the first time r - etpa in an organic molecular dye, indocyanine green ( icg ), when excited by broadband entangled photons in near - ir. similar to many reported virtual state mediated etpa ( v - etpa ) measurements, no r - etpa signals are measured, with an experimental upper bound for the cross section placed at $ 6 \ times 10 ^ { - 23 } $ cm $ ^ 2 $ / molecule. in addition, the classical resonance - enhanced two - photon absorption ( r - tpa ) cross section of icg at 800 nm is measured for the first time to be $ 20 ( \ pm13 ) $ gm, suggesting that having a resonant intermediate state does not significantly enhance two - photon processes in icg. the spectrotemporally resolved emission signatures of icg excited by entangled photons are also presented to support this conclusion. | arxiv:2312.14382 |
we prove a generalizations of the elekes - szab \ ' o theorem for relations definable in strongly minimal structures that are interpretable in distal structures. | arxiv:1801.09301 |
the aim of this paper is to describe some partial advances in the solution of the following two problems. find the maximal order of vanishing at infinity of a non - zero drinfeld quasi - modular form of given weight. determine differential properties of a drinfeld quasi - modular form of given weight and depth with maximal order of vanishing at infinity. | arxiv:0902.0164 |
interactive program verification is characterized by iterations of unfinished proof attempts. to support the process of constructing a complete proof, many interactive program verification systems offer a proof scripting language as a text - based way to describe the non - automatic steps in a proof. such scripting languages are beneficial, but users spent a lot of effort on inspecting proof scripts and the proofs they construct to detect the cause when a proof attempt is unsuccessful and leads to unintended proof states. we present an offline and replay debugger to support the user in analyzing proof attempts performed with proof scripts. this debugger adapts successful concepts from software debugging to the area of proof script debugging. the tool is built on top of key, a system for deductive verification of java programs. the debugger and its graphical user interface are designed to support program verification in particular, the underlying concepts and the implementation, however, are adaptable to other provers and proof tasks. | arxiv:1804.04402 |
sequential change - point detection for time series is widely used in data monitoring in practice. in this work, we focus on sequential change - point detection on high - order compositional time series models. under the regularity conditions, we prove that a process following the generalized beta ar ( p ) model with exogenous variables is stationary and ergodic. we develop a nonparametric sequential change - point detection method for the generalized beta ar ( p ) model, which does not rely on any strong assumptions about the sources of the change points. we show that the power of the test converges to one given that the amount of initial observations is large enough. we apply the nonparametric method to a rate of automobile crashes with alcohol involved, which is recorded monthly from january 2010 to december 2020 ; the exogenous variable is the price level of alcoholic beverages, which has a change point around august 2019. we fit a generalized beta ar ( p ) model to the crash rate sequence, and we use the nonparametric sequential change - point detection method to successfully detect the change point. | arxiv:2503.02349 |
the l1 - regularized gaussian maximum likelihood estimator ( mle ) has been shown to have strong statistical guarantees in recovering a sparse inverse covariance matrix, or alternatively the underlying graph structure of a gaussian markov random field, from very limited samples. we propose a novel algorithm for solving the resulting optimization problem which is a regularized log - determinant program. in contrast to recent state - of - the - art methods that largely use first order gradient information, our algorithm is based on newton ' s method and employs a quadratic approximation, but with some modifications that leverage the structure of the sparse gaussian mle problem. we show that our method is superlinearly convergent, and present experimental results using synthetic and real - world application data that demonstrate the considerable improvements in performance of our method when compared to other state - of - the - art methods. | arxiv:1306.3212 |
we explore a model of the early universe in which the inflationary epoch is preceded by a cosmic bounce, and argue that this scenario provides a common origin to several of the anomalous features that have been observed at large angular scales in the cosmic microwave background ( cmb ). more concretely, we show that a power suppression, a dipolar asymmetry, and a preference for odd - parity correlations, with amplitude and scale dependence in consonance with observations, are expected from this scenario. the model also alleviates the tension in the lensing amplitude. these signals originate from the indirect effect that non - gaussian correlations between cmb modes and super - horizon wavelengths induce in the power spectrum. we do not restrict to any specific theory, but rather derive features common to a family bouncing models. | arxiv:2005.01796 |
we study in detail the quantization of a model which apparently describes chiral bosons. the model is based on the idea that the chiral condition could be implemented through a linear constraint. we show that the space of states is of indefinite metric. we cure this disease by introducing ghost fields in such a way that a brst symmetry is generated. a quartet algebra is seen to emerge. the quartet mechanism, then, forces all physical states, but the vacuum, to have zero norm. | arxiv:hep-th/9202043 |
we argue why the recently observed $ t _ { cc } $ could either be a compact multiquark configuration or a loosely bound molecular configuration composed of charmed mesons, whereas the $ x ( 3872 ) $ is most likely a molecular configuration. the argument is based on different short range interactions for these tetraquark states coming from the color - color and color - spin interaction in a quark model, and the presence of a common strong d - wave mixing at larger distance similar to the deuteron case, which for the molecular configurations lead to large sizes. such an analogy at large distance allows us to calculate the transverse momentum dependence of the loosely bound molecular configuration of tetraquarks produced in heavy ion collisions using the coalescence model that successfully reproduces the deutron data using the proton spectra. the ratio of the integrated $ x ( 3872 ) $ yield obtained from our method to the $ \ psi ( 2s ) $ yield obtained from statistical hadronization model method is calculated to be $ 0. 806 \ pm 0. 234 $, which is a factor of 2. 47 larger than that obtained by using statistical model predictions for both particles and in line with the data from the cms experiment. as the previously calculated transverse momentum distribution of the $ t _ { cc } $ assuming the structure to be a compact multiquark configuration is markedly different, experimental measurements of the transverse distribution of the tetraquark states will discriminate between their two possible structures. | arxiv:2208.06960 |
we provide tools to analyze information design problems subject to constraints. we do so by extending the insight in le treust and tomala ( 2019 ) to the case of multiple inequality and equality constraints. namely, that an information design problem subject to constraints can be represented as an unconstrained information design problem with a additional states, one for each constraint. thus, without loss of generality, optimal solutions induce as many posteriors as the number of states and constraints. we provide results that refine this upper bound. furthermore, we provide conditions under which there is no duality gap in constrained information design, thus validating a lagrangian approach. we illustrate our results with applications to mechanism design with limited commitment ( doval and skreta, 2022a ) and persuasion of a privately informed receiver ( kolotilin et al., 2017 ). | arxiv:1811.03588 |
this is the second of a series of papers in which we investigate the decay estimates for dispersive equations with aharonov - bohm solenoids in a uniform magnetic field. in our first starting paper \ cite { wzz }, we have studied the strichartz estimates for schr \ " odinger equation with one aharonov - bohm solenoid in a uniform magnetic field. the wave equation in this setting becomes more delicate since a difficulty is raised from the square root of the eigenvalue of the schr \ " odinger operator $ h _ { \ alpha, b _ 0 } $ so that we cannot directly construct the half - wave propagator. an independent interesting result concerning the gaussian upper bounds of the heat kernel is proved by using two different methods. the first one is based on establishing davies - gaffney inequality in this setting and the second one is straightforward to construct the heat kernel ( which efficiently captures the magnetic effects ) based on the schulman - sunada formula. as byproducts, we prove optimal bounds for the heat kernel and show the bernstein inequality and the square function inequality for schr \ " odinger operator with one aharonov - bohm solenoid in a uniform magnetic field. | arxiv:2309.07649 |
a set $ y \ subseteq \ mathbb { r } ^ d $ that intersects every convex set of volume $ 1 $ is called a danzer set. it is not known whether there are danzer sets in $ \ mathbb { r } ^ d $ with growth rate $ o ( t ^ d ) $. we prove that natural candidates, such as discrete sets that arise from substitutions and from cut - and - project constructions, are not danzer sets. for cut and project sets our proof relies on the dynamics of homogeneous flows. we consider a weakening of the danzer problem, the existence of uniformly discrete dense forests, and we use homogeneous dynamics ( in particular ratner ' s theorems on unipotent flows ) to construct such sets. we also prove an equivalence between the above problem and a well - known combinatorial problem, and deduce the existence of danzer sets with growth rate $ o ( t ^ d \ log t ) $, improving the previous bound of $ o ( t ^ d \ log ^ { d - 1 } t ) $. | arxiv:1406.3807 |
we present results from the first large - scale survey of neutron ( n ) - capture element abundances in planetary nebulae ( pne ). this survey was motivated by the fact that a pn may be enriched in n - capture elements if its progenitor star experienced s - process nucleosynthesis during the asymptotic giant branch ( agb ) phase. [ kr iii ] 2. 199 and / or [ se iv ] 2. 287 $ \ mu $ m were detected in 81 pne out of 120 pne, for a detection rate of nearly 70 %. we derive se and kr abundances or upper limits using ionization correction factors derived from photoionization models. a significant range is found in the se and kr abundances, from near solar ( no enrichment ), to enriched by a factor of ten. our survey has increased the number of pne with known n - capture element abundances by an order of magnitude, enabling us to explore correlations between s - process enrichments and other nebular and central star properties. in particular, the se and kr enrichments display a positive correlation with nebular c / o ratios, as theoretically expected. peimbert type i pne and bipolar pne, whose progenitors are believed to be intermediate - mass stars ( > 3 - 4 m _ sun ), exhibit little or no s - process enrichment. interestingly, pne with h - deficient [ wc ] central stars do not exhibit systematically larger s - process enrichments than other pne, despite the fact that their central stars are enriched in c and probably n - capture elements. finally, the few pne in our sample with known or probable binary central star systems exhibit little s - process enrichment, which may be explained if binary interactions truncated their agb phases. we also briefly discuss a new observational program to detect optical emission lines of n - capture elements, and new atomic data calculations that will greatly improve the accuracy of n - capture element abundance determinations in pne. | arxiv:0708.1323 |
time series account for a large proportion of the data stored in financial, medical and scientific databases. the efficient storage of time series is important in practical applications. in this paper, we propose a novel compression scheme for time series. the encoder and decoder are both composed by recurrent neural networks ( rnn ) such as long short - term memory ( lstm ). there is an autoencoder between encoder and decoder, which encodes the hidden state and input together and decodes them at the decoder side. moreover, we pre - process the original time series by partitioning it into segments with various lengths which have similar total variation. the experimental study shows that the proposed algorithm can achieve competitive compression ratio on real - world time series. | arxiv:1707.07961 |
the study of multidimensional stochastic processes involves complex computations in intricate functional spaces. in particular, the diffusion processes, which include the practically important gauss - markov processes, are ordinarily defined through the theory of stochastic integration. here, inspired by the l \ ' { e } vy - cieselski construction of the wiener process, we propose an alternative representation of multidimensional gauss - markov processes as expansions on well - chosen schauder bases, with independent random coefficients of normal law with zero mean and unitary variance. we thereby offer a natural multi - resolution description of gauss - markov processes as limits of the finite - dimensional partial sums of the expansion, that are strongly almost - surely convergent. moreover, such finite - dimensional random processes constitute an optimal approximation of the process, in the sense of minimizing the associated dirichlet energy under interpolating constraints. this approach allows simpler treatment in many applied and theoretical fields and we provide a short overview of applications we are currently developing. | arxiv:1009.0533 |
context : observations of transitional disks give us an understanding of the formation of planets and planetary systems such as our own. but care must be taken in the identification of such sources : the higher spatial resolution of the herschel space observatory provides a new view on the origin of the far - infrared and sub - millimeter excesses observed. aims : we review the nature of previously known transitional disks in the chamaeleon i star - forming region with herschel data. methods : we analyze herschel pacs and spire images of the young star t54 together with ancillary images. we also analyze its spectral energy distribution and indications from optical and mid - infrared spectroscopy. results : we detect extended emission in the pacs 70 \ mu m image ~ 6 " off source at a position angle of 196 { \ deg } from t54. the emission detected at longer wavelength ( pacs 100, 160, spire 250 and 350 \ mu m ) is also offset from the position of the star. this suggests that the excess observed in the far - infrared part of the sed is not fully associated with t54. conclusions : herschel images show that the far - infrared excess seen in t54 is not due to a transitional disk but to extended emission south - west of the source. the object still shows point - like and now downscaled excess at mid - infrared wavelengths, but its origin cannot be constrained without higher spatial resolution data. however, different indications point towards an evolved disk or extended unresolved emission close to the source. | arxiv:1210.7679 |
there are ongoing divisions in the learning sciences between perspectives that treat cognition as occurring within individual minds and those that treat it as irreducibly distributed or situated in material and social contexts. we contend that accounts of individual minds as complex systems are theoretically continuous with distributed and situated cognition. on this view, the difference is a matter of the scale of the dynamics of interest, and the choice of scale can be informed by data. in this paper, we propose heuristics for empirically determining the scale of the relevant cognitive dynamics. we illustrate these heuristics in two contrasting cases, one in which the evidence supports attributing cognition to a group of students and one in which the evidence supports attributing cognition to an individual. | arxiv:1003.0491 |
one of the main objectives of equilibrium state statistical physics is to analyze which symmetries of an interacting particle system in equilibrium are broken or conserved. here we present a general result on the conservation of translational symmetry for two - dimensional gibbsian particle systems. the result applies to particles with internal degrees of freedom and fairly arbitrary interaction, including the interesting cases of discontinuous, singular, and hard core interaction. in particular we thus show the conservation of translational symmetry for the continuum widom rowlinson model and a class of continuum potts type models. | arxiv:math/0603140 |
diffusion is an ubiquitous phenomenon. it is a widespread belief that as long as the area under a current autocorrelation function converges in time, the corresponding spatiotemporal density dynamics should be diffusive. this may be viewed as a result of the combination of linear response theory with the einstein relation. however, attempts to derive this statement from first principles are notoriously challenging. we first present a counterexample by constructing a correlation functions of some density wave, such that the area under the corresponding current autocorrelation function converges, but the dynamics do not obey a diffusion equation. then we will introduce a method based on the recursion method and the mori memory formalism, that may help to actually identify diffusion. for a decisive answer, one would have to know infinitely many so called lanczos coefficients, which is unattainable in most cases. however, in the examples examined in this paper, we find that the practically computable number of lanczos coefficients suffices for a strong guess. | arxiv:2502.18095 |
diffusion transformer ( dit ) is a crucial method for content generation. however, it needs a lot of time to sample. many studies have attempted to use caching to reduce the time consumption of sampling. existing caching methods accelerate generation by reusing dit features from the previous time step and skipping calculations in the next, but they tend to locate and cache low - error modules without focusing on reducing caching - induced errors, resulting in a sharp decline in generated content quality when increasing caching intensity. to solve this problem, we propose the error - optimized cache ( eoc ). this method introduces three key improvements : ( 1 ) prior knowledge extraction : extract and process the caching differences ; ( 2 ) a judgment method for cache optimization : determine whether certain caching steps need to be optimized ; ( 3 ) cache optimization : reduce caching errors. experiments show that this algorithm significantly reduces the error accumulation caused by caching, especially excessive caching. on the imagenet dataset, without substantially increasing the computational load, this method improves the fid of the generated images when the rule - based model fora has a caching level of 75 %, 50 %, and 25 %, and the training - based model learning - to - cache has a caching level of 22 %. specifically, the fid values change from 30. 454 to 21. 690 ( 28. 8 % ), from 6. 857 to 5. 821 ( 15. 1 % ), from 3. 870 to 3. 692 ( 4. 6 % ), and from 3. 539 to 3. 451 ( 2. 5 % ) respectively. | arxiv:2501.19243 |
diffuse large b - cell lymphoma ( dlbcl ) is the most common non - hodgkin lymphoma. though histologically dlbcl shows varying morphologies, no morphologic features have been consistently demonstrated to correlate with prognosis. we present a morphologic analysis of histology sections from 209 dlbcl cases with associated clinical and cytogenetic data. duplicate tissue core sections were arranged in tissue microarrays ( tmas ), and replicate sections were stained with h & e and immunohistochemical stains for cd10, bcl6, mum1, bcl2, and myc. the tmas are accompanied by pathologist - annotated regions - of - interest ( rois ) that identify areas of tissue representative of dlbcl. we used a deep learning model to segment all tumor nuclei in the rois, and computed several geometric features for each segmented nucleus. we fit a cox proportional hazards model to demonstrate the utility of these geometric features in predicting survival outcome, and found that it achieved a c - index ( 95 % ci ) of 0. 635 ( 0. 574, 0. 691 ). our finding suggests that geometric features computed from tumor nuclei are of prognostic importance, and should be validated in prospective studies. | arxiv:2009.08123 |
the set of stable matchings induces a distributive lattice. the supremum of the stable matching lattice is the boy - optimal ( girl - pessimal ) stable matching and the infimum is the girl - optimal ( boy - pessimal ) stable matching. the classical boy - proposal deferred - acceptance algorithm returns the supremum of the lattice, that is, the boy - optimal stable matching. in this paper, we study the smallest group of girls, called the { \ em minimum winning coalition of girls }, that can act strategically, but independently, to force the boy - proposal deferred - acceptance algorithm to output the girl - optimal stable matching. we characterize the minimum winning coalition in terms of stable matching rotations and show that its cardinality can take on any value between $ 0 $ and $ \ left \ lfloor \ frac { n } { 2 } \ right \ rfloor $, for instances with $ n $ boys and $ n $ girls. our main result is that, for the random matching model, the expected cardinality of the minimum winning coalition is $ ( \ frac { 1 } { 2 } + o ( 1 ) ) \ log { n } $. this resolves a conjecture of kupfer \ cite { kup18 }. | arxiv:2007.15748 |
recent remarkable progress in computing power and numerical analysis is enabling us to fill a gap in the dynamical systems approach to turbulence. one of the significant advances in this respect has been the numerical discovery of simple invariant sets, such as nonlinear equilibria and periodic solutions, in well - resolved navier - - stokes flows. this review describes some fundamental and practical aspects of dynamical systems theory for the investigation of turbulence, focusing on recently found invariant solutions and their significance for the dynamical and statistical characterization of low - reynolds - number turbulent flows. it is shown that the near - wall regeneration cycle of coherent structures can be reproduced by such solutions. the typical similarity laws of turbulence, i. e. the prandtl wall law and the kolmogorov law for the viscous range, as well as the pattern and intensity of turbulence - driven secondary flow in a square duct can also be represented by these simple invariant solutions. | arxiv:1108.0975 |
to understand the superconductivity in mgb2, several two - band models of superconductivity were proposed. in this paper, by using the relativistic fermion model, we clearize the effect of the lower band in the superconductivity. | arxiv:cond-mat/0306472 |
on august 17, 2017 at 12 : 41 : 04 utc the advanced ligo and advanced virgo gravitational - wave detectors made their first observation of a binary neutron star inspiral. the signal, gw170817, was detected with a combined signal - to - noise ratio of 32. 4 and a false - alarm - rate estimate of less than one per $ 8. 0 \ times10 ^ 4 $ years. we infer the component masses of the binary to be between 0. 86 and 2. 26 $ m _ \ odot $, in agreement with masses of known neutron stars. restricting the component spins to the range inferred in binary neutron stars, we find the component masses to be in the range 1. 17 to 1. 60 $ m _ \ odot $, with the total mass of the system $ 2. 74 ^ { + 0. 04 } _ { - 0. 01 } \, m _ \ odot $. the source was localized within a sky region of 28 deg $ ^ 2 $ ( 90 % probability ) and had a luminosity distance of $ 40 ^ { + 8 } _ { - 14 } $ mpc, the closest and most precisely localized gravitational - wave signal yet. the association with the gamma - ray burst grb 170817a, detected by fermi - gbm 1. 7 s after the coalescence, corroborates the hypothesis of a neutron star merger and provides the first direct evidence of a link between these mergers and short gamma - ray bursts. subsequent identification of transient counterparts across the electromagnetic spectrum in the same location further supports the interpretation of this event as a neutron star merger. this unprecedented joint gravitational and electromagnetic observation provides insight into astrophysics, dense matter, gravitation and cosmology. | arxiv:1710.05832 |
we describe certain criteria for a motif $ m $ to be $ r $ - effective, i. e., to belong to the $ r $ th tate twist $ obj dm ^ { eff } _ { gm, r } ( r ) = obj dm ^ { eff } _ { gm, r } \ otimes l ^ { \ otimes r } $ of effective voevodsky motives ( for $ r \ ge 1 $ ; $ r $ is the coefficient ring ). in particular, $ m $ is 1 - effective if and only if a complex whose terms are certain chow groups of zero - cycles is acyclic. the dual to this statement checks whether an effective motif $ m $ belongs to the subcategory of $ dm ^ { eff } _ { gm, r } $ generated by motives of varieties of dimension $ \ le r $. these criteria are formulated in terms of the chow - weight ( co ) homology of $ m $. these ( co ) homology theories are introduced in the current paper and have several ( other ) remarkable properties : they yield a bound on the " weights " of $ m $ ( in the sense of the chow weight structure defined by the first author ) and detect the effectivity of " the lower weight pieces " of $ m $. we also calculate the " connectivity " of $ m $ ( in the sense of voevodsky ' s homotopy t - structure ) and prove that the exponents of the higher motivic homology groups ( of an " integral " motif ) are bounded whenever these groups are torsion. these motivic properties of $ m $ have important consequences for its cohomology. as a corollary, we prove that if chow groups of an arbitrary variety $ x $ vanish up to dimension $ r - 1 $ then the highest deligne weight factors of the ( singular or \ ' etale ) cohomology of $ x $ with compact support are $ r $ - effective in the naturally defined sense. our results yield a vast generalization of the so - called " decomposition of the diagonal " statements. | arxiv:1411.6354 |
the laser interferometer space antenna ( lisa ) will open three decades of gravitational wave ( gw ) spectrum between 0. 1 and 100 mhz, the mhz band. this band is expected to be the richest part of the gw spectrum, in types of sources, numbers of sources, signal - to - noise ratios and discovery potential. when lisa opens the low - frequency window of the gravitational wave spectrum, around 2034, the surge of gravitational - wave astronomy will strongly compel a subsequent mission to further explore the frequency bands of the gw spectrum that can only be accessed from space. the 2020s is the time to start developing technology and studying mission concepts for a large - scale mission to be launched in the 2040s. the mission concept would then be proposed to astro2030. only space based missions can access the gw spectrum between 10 nhz and 1 hz because of the earths seismic noise. this white paper surveys the science in this band and mission concepts that could accomplish that science. the proposed small scale activity is a technology development program that would support a range of concepts and a mission concept study to choose a specific mission concept for astro2030. in this white paper, we will refer to a generic gw mission beyond lisa as blisa. | arxiv:1907.11305 |
. java software runs on most devices from laptops to data centers, game consoles to scientific supercomputers. oracle ( and others ) highly recommend uninstalling outdated and unsupported versions of java, due to unresolved security issues in older versions. = = = principles = = = there were five primary goals in creating the java language : it must be simple, object - oriented, and familiar. it must be robust and secure. it must be architecture - neutral and portable. it must execute with high performance. it must be interpreted, threaded, and dynamic. = = = versions = = = as of november 2024, java 8, 11, 17, and 21 are supported as long - term support ( lts ) versions, with java 25, releasing in september 2025, as the next scheduled lts version. oracle released the last zero - cost public update for the legacy version java 8 lts in january 2019 for commercial use, although it will otherwise still support java 8 with public updates for personal use indefinitely. other vendors such as adoptium continue to offer free builds of openjdk ' s long - term support ( lts ) versions. these builds may include additional security patches and bug fixes. major release versions of java, along with their release dates : = = editions = = sun has defined and supports four editions of java targeting different application environments and segmented many of its apis so that they belong to one of the platforms. the platforms are : java card for smart - cards. java platform, micro edition ( java me ) – targeting environments with limited resources. java platform, standard edition ( java se ) – targeting workstation environments. java platform, enterprise edition ( java ee ) – targeting large distributed enterprise or internet environments. the classes in the java apis are organized into separate groups called packages. each package contains a set of related interfaces, classes, subpackages and exceptions. sun also provided an edition called personal java that has been superseded by later, standards - based java me configuration - profile pairings. = = execution system = = = = = java jvm and bytecode = = = one design goal of java is portability, which means that programs written for the java platform must run similarly on any combination of hardware and operating system with adequate run time support. this is achieved by compiling the java language code to an intermediate representation called java bytecode, instead of directly to architecture - specific machine code. java bytecode instructions are analogous to machine code, but they are | https://en.wikipedia.org/wiki/Java_(programming_language) |
the bdi model proved to be effective for developing applications requiring high - levels of autonomy and to deal with the complexity and unpredictability of real - world scenarios. the model, however, has significant limitations in reacting and handling contingencies within the given real - time constraints. without an explicit representation of time, existing real - time bdi implementations overlook the temporal implications during the agent ' s decision process that may result in delays or unresponsiveness of the system when it gets overloaded. in this paper, we redefine the bdi agent control loop inspired by well established algorithms for real - time systems to ensure a proper reaction of agents and their effective application in typical real - time domains. our model proposes an effective real - time management of goals, plans, and actions with respect to time constraints and resources availability. we propose an implementation of the model for a resource - collection video - game and we validate the approach against a set of significant scenarios. | arxiv:2205.00979 |
we report on a large scale computer simulation study of crystal nucleation in hard spheres. through a combined analysis of real and reciprocal space data, a picture of a two - step crystallization process is supported : first dense, amorphous clusters form which then act as precursors for the nucleation of well - ordered crystallites. this kind of crystallization process has been previously observed in systems that interact via potentials that have an attractive as well as a repulsive part, most prominently in protein solutions. in this context the effect has been attributed to the presence of metastable fluid - fluid demixing. our simulations, however, show that a purely repulsive system ( that has no metastable fluid - fluid coexistence ) crystallizes via the same mechanism. | arxiv:1003.2552 |
over the last fifteen years, web searching has seen tremendous improvements. starting from a nearly random collection of matching pages in 1995, today, search engines tend to satisfy the user ' s informational need on well - formulated queries. one of the main remaining challenges is to satisfy the users ' needs when they provide a poorly formulated query. when the pages matching the user ' s original keywords are judged to be unsatisfactory, query expansion techniques are used to alter the result set. these techniques find keywords that are similar to the keywords given by the user, which are then appended to the original query leading to a perturbation of the result set. however, when the original query is sufficiently ill - posed, the user ' s informational need is best met using entirely different keywords, and a small perturbation of the original result set is bound to fail. we propose a novel approach that is not based on the keywords of the original query. we intentionally seek out orthogonal queries, which are related queries that have low similarity to the user ' s query. the result sets of orthogonal queries intersect with the result set of the original query on a small number of pages. an orthogonal query can access the user ' s informational need while consisting of entirely different terms than the original query. we illustrate the effectiveness of our approach by proposing a query expansion method derived from these observations that improves upon results obtained using the yahoo boss infrastructure. | arxiv:1109.0530 |
the tomographic description of a quantum state is formulated in an abstract infinite dimensional hilbert space framework, the space of the hilbert - schmidt linear operators, with trace formula as scalar product. resolutions of the unity, written in terms of over - complete sets of rank - one projectors and of associated gram - schmidt operators taking into account their non - orthogonality, are then used to reconstruct a quantum state from its tomograms. examples of well known tomographic descriptions illustrate the exposed theory. | arxiv:quant-ph/0604039 |
the basic concepts of the differential geometry are shortly reviewed and applied to the study of ves production function in the spirit of the works of v \ ^ ilcu and collaborators. a similar characterization is given for a more general production function, namely the kadiyala production function, in the case of developable surfaces. | arxiv:2004.09617 |
this paper studies the relationship between the positive limit sets of continuous semiflows and the newly introduced definition of persistently excited ( pe ) sets and associated subspaces of reproducing kernel hilbert ( rkh ) spaces. it is shown that if the rkh space contains a rich collection of cut - off functions, persistently excited sets are contained as subsets of the positive limit set of the semiflow. the paper demonstrates how the new pe condition can be used to guarantee convergence of function estimates in the rkh space embedding method for adaptive estimation. in particular, the paper is applied to uncertain ode systems with positive limit sets given by certain types of smooth manifolds, and it establishes convergence of adaptive function estimates over the manifolds. | arxiv:1909.12274 |
in geotechnical engineering, a caisson ( ; borrowed from french caisson ' box ', from italian cassone ' large box ', an augmentative of cassa ) is a watertight retaining structure. it is used, for example, to work on the foundations of a bridge pier, for the construction of a concrete dam, or for the repair of ships. caissons are constructed in such a way that the water can be pumped out, keeping the work environment dry. when piers are being built using an open caisson, and it is not practical to reach suitable soil, friction pilings may be driven to form a suitable sub - foundation. these piles are connected by a foundation pad upon which the column pier is erected. caisson engineering has been used since at least the 19th century, with three prominent examples being the royal albert bridge ( completed in 1859 ), the eads bridge ( completed in 1874 ), and the brooklyn bridge ( completed in 1883 ). = = types = = to install a caisson in place, it is brought down through soft mud until a suitable foundation material is encountered. while bedrock is preferred, a stable, hard mud is sometimes used when bedrock is too deep. the four main types of caisson are box caisson, open caisson, pneumatic caisson and monolithic caisson. = = = box = = = a box caisson is a prefabricated box ( with sides and a bottom ) ; where required it is set down on a prepared base. once in place, it is filled with ballast to become part of the works, such as the foundation for a bridge pier. hollow concrete structures are generally less dense than water so a box caisson must be secured to prevent it from moving offsite until it can be filled with ballast. sometimes elaborate anchoring systems may be required, such as in tidal zones. adjustable anchoring systems combined with a gps survey enable engineers to position a box caisson with pinpoint accuracy. = = = open = = = an open caisson is similar to a box caisson, except that it does not have a bottom face. it is suitable for use in soft clays ( e. g. in some river - beds ), but not for where there may be large obstructions in the ground. an open caisson that is used in soft grounds or high water tables, where open trench excavations are impractical, can also be used to install deep manholes, pump stations and reception / launch pits for microtunne | https://en.wikipedia.org/wiki/Caisson_(engineering) |
the time - dependent non - crossing approximation is utilized to determine the effects of the crystal planes of gold contacts on time dependent current through a quantum dot suddenly shifted into the kondo regime via a gate voltage. for an asymmetrically coupled system, instantaneous conductance exhibits complex fluctuations. we identify the frequencies participating in these fluctuations and they turn out to be proportional to the separation between the sharp features in the density of states and the fermi level in agreement with previous studies. based on this observation, we predict that using different crystal planes as electrodes would give rise to drastically different transient currents which can be accessed with ultrafast pump - probe techniques. | arxiv:1010.2631 |
in this paper, a new notion of frames is introduced : $ \ ast $ - operator frame as generalization of $ \ ast $ - frames in hilbert $ c ^ { \ ast } $ - modules introduced by a. alijani and m. a. dehghan \ cite { ali } and we establish some results. | arxiv:1806.03993 |
weak shear maps of the outer regions of clusters have been successfully used to map the distribution of mass at large radii from the cluster center. the typical smoothing lengths employed thus far preclude the systematic study of the effects of galactic - scale substructure on the measured weak lensing signal. in this paper, we present two methods to infer the possible existence and extent of dark halos around bright cluster galaxies by quantifying the ` local ' weak lensing induced by them. the proposed methods are : direct radial averaging of the shear field in the vicinity of bright cluster members and a maximum - likelihood method to extract fiducial parameters characterizing galaxy halos. we demonstrate using simulations that these observed local weak - shear effects on galaxy scales within the cluster can be used to statistically constrain the mean mass - to - light ratio, and fiducial parameters like the halo size, velocity dispersion and hence mass of cluster galaxies. we compare the two methods and investigate their relative drawbacks and merits in the context of feasibility of application to hst cluster data, whereby we find that the prospects are promising for detection on stacking a minimum of 20 wfpc2 deep cluster fields. | arxiv:astro-ph/9609008 |
indeed, these are exciting times. we are in the heart of a digital renaissance. automation and computer technology allow engineers and scientists to fabricate processes that amalgamate quality of life. we anticipate much growth in medical image interpretation and understanding, due to the influx of computer technologies. this work should serve as a guide to introduce the reader to core themes in theoretical computer science, as well as imaging applications for understanding vocal - fold vibrations. in this work, we motivate the use of automation, review some mathematical models of computation. we present a proof of a classical problem in image analysis that cannot be automated by means of algorithms. furthermore, discuss some applications for processing medical images of the vocal folds, and discuss some of the exhilarating directions the art of automation will take vocal - fold image interpretation and quite possibly other areas of biomedical image analysis. | arxiv:1212.6933 |
in recent years experiments revealed intriguing hints for new physics ( np ) in $ b $ decays involving \ bctaunu and $ b \ to s \ ell ^ + \ ell ^ - $ transitions at the $ 4 \, \ sigma $ and $ 5 \, \ sigma $ level, respectively. in addition, there are slight disagreements in $ b \ to u \ tau \ nu $ and $ b \ to d \ mu ^ + \ mu ^ - $ observables. while not significant on their own, they point in the same direction. furthermore, $ v _ { us } $ extracted from $ \ tau $ decays shows a slight tension ( $ \ approx2. 5 \, \ sigma $ ) with its value determined from ckm unitarity. additionally, belle found hints for an excess in $ b _ d \ to \ tau ^ + \ tau ^ - $. concerning np explanations, the vector leptoquark $ su ( 2 ) $ singlet is of special interest since it is the only single particle extension of the sm which can ( in principle ) address all the anomalies described above. for this purpose, large couplings to $ \ tau $ leptons are necessary and loop effects, which we calculate in this article, become important. including them in our phenomenological analysis, we find that neither the tension in $ v _ { us } $ nor the excess in $ b _ d \ to \ tau ^ + \ tau ^ - $ can be fully explained without violating bounds from $ k \ to \ pi \ nu \ bar \ nu $. however, one can account for $ b \ to c \ tau \ nu $ and $ b \ to u \ tau \ nu $ data finding intriguing correlations with $ b _ { q } \ to \ tau ^ + \ tau ^ - $ and $ k \ to \ pi \ nu \ bar \ nu $. furthermore, the explanation of $ b \ to c \ tau \ nu $ predicts a positive shift in $ c _ 7 $ and a negative one in $ c _ 9 $, being nicely in agreement with the global fit to $ b \ to s \ ell ^ + \ ell ^ - $ data. finally, we point out that one can fully account for \ bctaunu and $ b \ to s \ ell ^ + \ ell ^ - $ without violating bounds from $ \ tau \ to \ phi \ mu $, $ \ upsilo | arxiv:1807.02068 |
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