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in this article, we theoretically study, in an atomic - optomechanical system, quantum correlations shared between three modes, namely mechanical mode, optical mode and atomic mode. we firstly investigate the combined effect of the variation of the cavity - collective atomic mode coupling and the effective optomechanical one, on the tripartite entanglement behavior as well as on tripartite steering evolution. then, we discuss pairwise entanglement and bipartite steering according to the aforementioned couplings. consequently, besides monogamy of the entanglement distribution, the sharing of gaussian steering is also monogamous, thus the ckw - type monogamy inequalities are fully satisfied under all permutations of the three considered modes in a chosen stable region. in addition, the study of tripartite entanglement and tripartite steering behaviors leads to know the optimal conditions to generate genuine tripartite entanglement, one - way and two - way steering.
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arxiv:2311.04488
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recently a covariant entropy conjecture has been proposed for dynamical horizons. we apply this conjecture to concordance cosmological models, namely, those cosmological models filled with perfect fluids, in the presence of a positive cosmological constant. as a result, we find this conjecture has a severe constraint power. not only does this conjecture rule out those cosmological models disfavored by the anthropic principle, but also it imposes an upper bound $ 10 ^ { - 60 } $ on the cosmological constant for our own universe, which thus provides an alternative macroscopic perspective for understanding the long - standing cosmological constant problem.
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arxiv:0712.3821
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the notion of entanglement of quantum states is usually defined with respect to a fixed bipartition. indeed, a global basis change can always map an entangled state to a separable one. the situation is however different when considering a set of states. in this work we define the notion of an " absolutely entangled set " of quantum states : for any possible choice of global basis, at least one of the states in the set is entangled. hence, for all bipartitions, i. e. any possible definition of the subsystems, the set features entanglement. we present a minimum example of this phenomenon, with a set of four states in $ \ mathbb { c } ^ 4 = \ mathbb { c } ^ 2 \ otimes \ mathbb { c } ^ 2 $. moreover, we propose a quantitative measure for absolute set entanglement. to lower - bound this quantity, we develop a method based on polynomial optimization to perform convex optimization over unitaries, which is of independent interest.
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arxiv:2006.07165
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temporal action localization is an important step towards video understanding. most current action localization methods depend on untrimmed videos with full temporal annotations of action instances. however, it is expensive and time - consuming to annotate both action labels and temporal boundaries of videos. to this end, we propose a weakly supervised temporal action localization method that only requires video - level action instances as supervision during training. we propose a classification module to generate action labels for each segment in the video, and a deep metric learning module to learn the similarity between different action instances. we jointly optimize a balanced binary cross - entropy loss and a metric loss using a standard backpropagation algorithm. extensive experiments demonstrate the effectiveness of both of these components in temporal localization. we evaluate our algorithm on two challenging untrimmed video datasets : thumos14 and activitynet1. 2. our approach improves the current state - of - the - art result for thumos14 by 6. 5 % map at iou threshold 0. 5, and achieves competitive performance for activitynet1. 2.
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arxiv:2001.07793
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binarized neural networks ( bnn ) offer efficient implementations for machine learning tasks and facilitate privacy - preserving machine learning ( ppml ) by simplifying operations with binary values. nevertheless, challenges persist in terms of communication and accuracy in their application scenarios. in this work, we introduce cbnn, a three - party secure computation framework tailored for efficient bnn inference. leveraging knowledge distillation and separable convolutions, cbnn transforms standard bnns into mpc - friendly customized bnns, maintaining high utility. it performs secure inference using optimized protocols for basic operations. specifically, cbnn enhances linear operations with replicated secret sharing and mpc - friendly convolutions, while introducing a novel secure activation function to optimize non - linear operations. we demonstrate the effectiveness of cbnn by transforming and securely implementing several typical bnn models. experimental results indicate that cbnn maintains impressive performance even after customized binarization and security measures
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arxiv:2412.16449
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unveiling the key mechanisms that determine optically driven spin dynamics is essential both to probe the fundamental nature of ultrafast light - matter interactions, but also to drive future technologies of smaller, faster, and more energy efficient devices. essential to this task is the ability to use experimental spectroscopic tools to evidence the underlying energy - and spin - resolved dynamics of non - equilibrium electron occupations. in this joint theory and experimental work, we demonstrate that ultrafast helicity - dependent soft x - ray absorption spectroscopy ( hxas ) allows access to spin -, time - and energy specific state occupation after optical excitation. we apply this method to the prototype transition metal ferromagnet cobalt and find convincing agreement between theory and experiment. the richly structured energy - resolved spin dynamics unveil the subtle interplay and characteristic time scales of optical excitation and spin - orbit induced spin - flip transitions in this material : the spin moment integrated in an energy window below the fermi level first exhibits an ultrafast increase as minority carriers are excited by the laser pulse, before it is reduced as spin - flip process in highly localized, low energy states start to dominate. the results of this study demonstrate the power of element specific transient hxas, placing it as a potential new tool for identifying and determining the role of fundamental processes in optically driven spin dynamics in magnetic materials.
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arxiv:2205.03172
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due to the impressive amount of new data provided by the rxte satellite in the past decade, our knowledge of the phenomenology of accretion onto black holes has increased considerably. in particular, it has been possible to schematize the outburst evolution of transient systems on the basis of their spectral and timing properties, and link them to the ejection of relativistic jets as observed in the radio. here, i present this scheme, concentrating on the properties of the quasi - periodic oscillations observed in the light curves and on the link with jet ejection.
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arxiv:astro-ph/0507556
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in this survey, we describe controlled interacting particle systems ( cips ) to approximate the solution of the optimal filtering and the optimal control problems. part i of the survey is focussed on the feedback particle filter ( fpf ) algorithm, its derivation based on optimal transportation theory, and its relationship to the ensemble kalman filter ( enkf ) and the conventional sequential importance sampling - resampling ( sir ) particle filters. the central numerical problem of fpf - - to approximate the solution of the poisson equation - - is described together with the main solution approaches. an analytical and numerical comparison with the sir particle filter is given to illustrate the advantages of the cips approach. part ii of the survey is focussed on adapting these algorithms for the problem of reinforcement learning. the survey includes several remarks that describe extensions as well as open problems in this subject.
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arxiv:2301.00935
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the analysis of stochastic loss networks has long been of interest in computer and communications networks and is becoming important in the areas of service and information systems. in traditional settings, computing the well known erlang formula for blocking probability in these systems becomes intractable for larger resource capacities. using compound point processes to capture stochastic variability in the request process, we generalize existing models in this framework and derive simple asymptotic expressions for blocking probabilities. in addition, we extend our model to incorporate reserving resources in advance. although asymptotic, our experiments show an excellent match between derived formulas and simulation results even for relatively small resource capacities and relatively large values of blocking probabilities.
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arxiv:0708.4059
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we study the volume dependence of electric flux energies for su ( 2 ) gauge theory with twisted boundary conditions. the curves interpolate smoothly between the perturbative semiclassicalresults and the confinement regime. on the basis of our results, we propose that the confinement property might be caused by a class of non - dilute multi - instanton configurations.
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arxiv:hep-lat/9507001
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in order to see the behavior of $ \ imath $ canonical bases at $ q = \ infty $, we introduce the notion of $ \ imath $ crystals associated to an $ \ imath $ quantum group of certain quasi - split type. the theory of $ \ imath $ crystals clarifies why $ \ imath $ canonical basis elements are not always preserved under natural homomorphisms. also, we construct a projective system of $ \ imath $ crystals whose projective limit can be thought of as the $ \ imath $ canonical basis of the modified $ \ imath $ quantum group at $ q = \ infty $.
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arxiv:2110.07177
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training deep neural networks ( dnns ) usually requires massive training data and computational resources. users who cannot afford this may prefer to outsource training to a third party or resort to publicly available pre - trained models. unfortunately, doing so facilitates a new training - time attack ( i. e., backdoor attack ) against dnns. this attack aims to induce misclassification of input samples containing adversary - specified trigger patterns. in this paper, we first conduct a layer - wise feature analysis of poisoned and benign samples from the target class. we find out that the feature difference between benign and poisoned samples tends to be maximum at a critical layer, which is not always the one typically used in existing defenses, namely the layer before fully - connected layers. we also demonstrate how to locate this critical layer based on the behaviors of benign samples. we then propose a simple yet effective method to filter poisoned samples by analyzing the feature differences between suspicious and benign samples at the critical layer. we conduct extensive experiments on two benchmark datasets, which confirm the effectiveness of our defense.
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arxiv:2302.12758
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we introduce strong measuring, a maximal strengthening of j. t. moore ' s measuring principle, which asserts that every collection of fewer than continuum many closed bounded subsets of $ \ omega _ 1 $ is measured by some club subset of $ \ omega _ 1 $. the consistency of strong measuring with the negation of ch is shown, solving an open problem from about parametrized measuring principles. specifically, we prove that strong measuring follows from mrp together with martin ' s axiom for $ \ sigma $ - centered forcings, as well as from bpfa. we also consider strong versions of measuring in the absence of the axiom of choice.
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arxiv:1808.08596
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we propose a time - delayed feedback control scheme for open quantum systems that can dramatically reduce the time to reach steady state. no measurement is performed in the feedback loop, and we suggest a simple all - optical implementation for a cavity qed system. we demonstrate the potential of the scheme by applying it to a driven and dissipative dicke model, as recently realized in a quantum gas experiment. the time to reach steady state can then reduced by two orders of magnitude for parameters taken from experiment, making previously inaccessible long time attractors reachable within typical experimental run times. the scheme also offers the possibility of slowing down the dynamics, as well as qualitatively changing the phase diagram of the corresponding physical system.
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arxiv:1401.2287
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this paper introduces a control problem of regulation of energy flows in a two - site electricity and heat supply system, where two combined heat and power ( chp ) plants are interconnected via electricity and heat flows. the control problem is motivated by recent development of fast operation of chp plants to provide ancillary services of power system on the order of tens of seconds to minutes. due to the physical constraint that the responses of the heat subsystem are not necessary as fast as those of the electric subsystem, the target controlled state is not represented by any isolated equilibrium point, implying that stability of the system is lost in the long - term sense on the order of hours. in this paper, we first prove in the context of nonlinear control theory that the state - space model of the two - site system is non - minimum phase due to nonexistence of isolated equilibrium points of the associated zero dynamics. instead, we locate a one - dimensional invariant manifold that represents the target controlled flows completely. then, by utilizing a virtual output under which the state - space model becomes minimum phase, we synthesize a controller that achieves not only the regulation of energy flows in the short - term regime but also stabilization of an equilibrium point in the long - term regime. effectiveness of the synthesized controller is established with numerical simulations with a practical set of model parameters.
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arxiv:1809.03939
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autonomous - mobile cyber - physical machines are part of our future. specifically, unmanned - aerial - vehicles have seen a resurgence in activity with use - cases such as package delivery. these systems face many challenges such as their low - endurance caused by limited onboard - energy, hence, improving the mission - time and energy are of importance. such improvements traditionally are delivered through better algorithms. but our premise is that more powerful and efficient onboard - compute should also address the problem. this paper investigates how the compute subsystem, in a cyber - physical mobile machine, such as a micro aerial vehicle, impacts mission - time and energy. specifically, we pose the question as what is the role of computing for cyber - physical mobile robots? we show that compute and motion are tightly intertwined, hence a close examination of cyber and physical processes and their impact on one another is necessary. we show different impact paths through which compute impacts mission - metrics and examine them using analytical models, simulation, and end - to - end benchmarking. to enable similar studies, we open sourced mavbench, our tool - set consisting of a closed - loop simulator and a benchmark suite. our investigations show cyber - physical co - design, a methodology where robot ' s cyber and physical processes / quantities are developed with one another consideration, similar to hardware - software co - design, is necessary for optimal robot design.
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arxiv:1906.10513
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five - and four - dimensional superconformal field theories with eight supercharges arise from canonical threefold singularities in m - theory and type iib string theory, respectively. we study their coulomb and higgs branches using crepant resolutions and deformations of the singularities. we propose a relation between the resulting moduli spaces, by compactifying the theories to 3d, followed by 3d $ \ mathcal { n } = 4 $ mirror symmetry and an $ s $ - type gauging of an abelian flavor symmetry. in particular, we use this correspondence to determine the higgs branch of some 5d scfts and their magnetic quivers from the geometry. as an application of the general framework, we observe that singularities that engineer argyres - douglas theories in type iib also give rise to rank - 0 5d scfts in m - theory. we also compute the higher - form symmetries of the 4d and 5d scfts, including the one - form symmetries of generalized argyres - douglas theories of type $ ( g, g ' ) $.
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arxiv:2007.15600
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we have searched for exclusive 2 - photon production in proton - antiproton collisions at sqrt { s } = 1. 96 tev, using 532 / pb of integrated luminosity taken by the run ii collider detector at fermilab. the event signature requires two electromagnetic showers, each with transverse energy e _ t > 5 gev and pseudorapidity | eta | < 1. 0, with no other particles detected in the event. three candidate events are observed. we discuss the consistency of the three events with gamma - gamma, pi0 - pi0, or eta - eta production. the probability that other processes fluctuate to 3 events or more is 1. 7x10 ^ - 4. an upper limit on the cross section of p + pbar - - > p + gamma - gamma + pbar is set at 410 fb with 95 % confidence level.
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arxiv:0707.2374
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the special role played by singly polarized high - energy hadron - hadron collisions in spin physics is discussed : in such processes, the measured and the calculated quantities can be and have been directly compared with each other - - - without data - extrapolation and without sum rules. it is in this kind of processes, where significant asymmetries ( up to 30 - 40 \ % ) have been observed. it is also in this kind of processes, where the obtained data and the predictions of the conventional theories dramatically disagree with each other. attempts to understand the existing data are briefly summarized. predictions for further experiments are presented.
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arxiv:hep-ph/9510336
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we discuss the definition of condensates within light - cone quantum field theory. as the vacuum state in this formulation is trivial, we suggest to abstract vacuum properties from the particle spectrum. the latter can in principle be calculated by solving the eigenvalue problem of the light - cone hamiltonian. we focus on fermionic condensates which are order parameters of chiral symmetry breaking. as a paradigm identity we use the gell - mann - oakes - renner relation between the quark condensate and the observable pion mass. we examine the analogues of this relation in the ` t ~ hooft and schwinger model, respectively. a brief discussion of the nambu - jona - lasinio model is added.
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arxiv:hep-th/9608043
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this work addresses the challenge of hate speech detection in internet memes, and attempts using visual information to automatically detect hate speech, unlike any previous work of our knowledge. memes are pixel - based multimedia documents that contain photos or illustrations together with phrases which, when combined, usually adopt a funny meaning. however, hate memes are also used to spread hate through social networks, so their automatic detection would help reduce their harmful societal impact. our results indicate that the model can learn to detect some of the memes, but that the task is far from being solved with this simple architecture. while previous work focuses on linguistic hate speech, our experiments indicate how the visual modality can be much more informative for hate speech detection than the linguistic one in memes. in our experiments, we built a dataset of 5, 020 memes to train and evaluate a multi - layer perceptron over the visual and language representations, whether independently or fused. the source code and mode and models are available https : / / github. com / imatge - upc / hate - speech - detection.
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arxiv:1910.02334
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object pose estimation from a single view remains a challenging problem. in particular, partial observability, occlusions, and object symmetries eventually result in pose ambiguity. to account for this multimodality, this work proposes training a diffusion - based generative model for 6d object pose estimation. during inference, the trained generative model allows for sampling multiple particles, i. e., pose hypotheses. to distill this information into a single pose estimate, we propose two novel and effective pose selection strategies that do not require any additional training or computationally intensive operations. moreover, while many existing methods for pose estimation primarily focus on the image domain and only incorporate depth information for final pose refinement, our model solely operates on point cloud data. the model thereby leverages recent advancements in point cloud processing and operates upon an se ( 3 ) - equivariant latent space that forms the basis for the particle selection strategies and allows for improved inference times. our thorough experimental results demonstrate the competitive performance of our approach on the linemod dataset and showcase the effectiveness of our design choices. code is available at https : / / github. com / zitronian / 6dposediffusion.
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arxiv:2412.00835
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recent co - part segmentation methods mostly operate in a supervised learning setting, which requires a large amount of annotated data for training. to overcome this limitation, we propose a self - supervised deep learning method for co - part segmentation. differently from previous works, our approach develops the idea that motion information inferred from videos can be leveraged to discover meaningful object parts. to this end, our method relies on pairs of frames sampled from the same video. the network learns to predict part segments together with a representation of the motion between two frames, which permits reconstruction of the target image. through extensive experimental evaluation on publicly available video sequences we demonstrate that our approach can produce improved segmentation maps with respect to previous self - supervised co - part segmentation approaches.
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arxiv:2004.03234
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in a series of two papers, we investigate the large deviations and asymptotic behavior of stochastic models of brain neural networks with random interaction coefficients. in this first paper, we take into account the spatial structure of the brain and consider ( i ) the presence of interaction delays that depend on the distance between cells and ( ii ) gaussian random interaction amplitude whose mean and variance depend on the neurons positions and scale as the inverse of the network size. we show that the empirical measure satisfies a large - deviation principle with good rate function reaching its minimum at a unique spatially extended probability measure. this result implies averaged convergence of the empirical measure and propagation of chaos. the limit is characterized through complex non - markovian implicit equation in which the network interaction term is replaced by a non - local gaussian process whose statistics depend on the solution over the whole neural field.
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arxiv:1510.06957
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prof. k. g ramanathan was a legendary indian mathematician, working in number theory and a prolific institution builder. apart from this, he was an excellent teacher and influenced several brilliant students. in this article, we overview his life and discuss some of his significant mathematical contributions
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arxiv:2209.04901
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the iron - based superconductors are an ideal platform to reveal the enigma of the unconventional superconductivity and potential topological superconductivity. among them, the monolayer fe ( se, te ) / srtio3 ( 001 ), which is proposed to be topological nontrivial, shows interface - enhanced high - temperature superconductivity in the two dimensional limit. however, the experimental studies on the superconducting pairing mechanism of monolayer fe ( se, te ) films are still limited. here, by measuring quasiparticle interference in monolayer fe ( se, te ) / srtio3 ( 001 ), we report the observation of the anisotropic structure of the large superconducting gap and the sign change of the superconducting gap on different electron pockets. the results are well consistent with the ' bonding - antibonding ' s + - wave pairing symmetry driven by spin fluctuations in conjunction with spin - orbit coupling. our work is of basic significance not only for a unified superconducting formalism in the iron - based superconductors, but also for understanding of topological superconductivity in high - temperature superconductors.
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arxiv:2209.08683
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malaria, a mosquito - borne disease caused by a parasite, kills over 1 million people globally each year. people, if left untreated, may develop severe complications, leading to death. effective and accurate diagnosis is important for the management and control of malaria. our research focuses on utilizing machine learning to improve the efficiency in malaria diagnosis. we utilize a modified u - net architecture, as an unsupervised learning model, to conduct cell boundary detection. the blood cells infected by malaria are then identified in chromatic space by a mahalanobis distance algorithm. both the cell segmentation and malaria detection process often requires intensive manual label, which we hope to eliminate via the unsupervised workflow.
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arxiv:2009.00197
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odderon induced contributions to exclusive photoproduction of $ \ pi ^ { \ circ } $, $ f _ 2 ( 1270 ) $ and $ a _ 2 ( 1320 ) $ have been searched for at hera, using the multiphoton decays of these mesons. no indication for such contributions was found, in a kinematic region defined by the average photon - proton centre - of - mass energy $ < w > = 200 - 215 $ gev, photon virtualities $ q ^ 2 < 0. 01 $ gev $ ^ 2 $ and $ 0. 02 $ gev $ ^ 2 < | t | < 0. 3 $ gev $ ^ 2 $, where t is the squared momentum transfer at the proton vertex. the measured upper limits for the cross sections, $ \ sigma ( \ gamma p \ to ^ { \ hspace * { - 2ex } \ mathbb { o } } \ pi ^ { \ circ } n ^ { \ ast } ) < 39 $ nb, $ \ sigma ( \ gamma p \ to ^ { \ hspace * { - 2ex } \ mathbb { o } } f _ 2 ( 1270 ) x ) < 16 $ nb and $ \ sigma ( \ gamma p \ to ^ { \ hspace * { - 2ex } \ mathbb { o } } a _ 2 ( 1320 ) x ) < 96 $ nb, all at 95 % cl, are lower than the predictions by a theoretical model. exclusive photoproduction of $ \ omega $ and $ \ omega \ pi ^ { \ circ } $, in the $ 3 \ gamma $ and $ 5 \ gamma $ decay modes, is observed with the expected cross sections.
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arxiv:hep-ex/0112012
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we study the dynamics of inorganic antiferroelectric nanoclusters formed during an order - disorder transition and demonstrate the coexistence of the two phases in a region of 2 - 3 k around the transition temperature tn ~ 215 k. single crystals of nh4h2aso4, a model hydrogen - bonded compound, show an antiferroelectric - paraelectric transition studied by means of highly sensitive magic angle spinning 15n nmr at 21. 1 t. the phase co - existence is demonstrated by a double - peak structure of the chemical shift. two - dimensional chemical exchange spectroscopy and spin - lattice relaxation time ( t1 ) measurements show that the clusters are dynamic with sizes ~ 50 nm and lifetimes approaching seconds as t - > tn. their occupancy increases rapidly to fill the crystal volume below $ t _ n $. this study provides evidence for the commonality of the phase transitions in systems with electric properties and provides an improved spectroscopic method for such studies.
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arxiv:1504.06124
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in the search for topological phases in correlated electron systems, iridium - based pyrochlores a2ir2o7 - - materials with 5d transition - metal ions - - provide fertile grounds. several novel topological states have been predicted but the actual realization of such states is believed to critically depend on the strength of local potentials arising from distortions of iro6 - cages. we test this hypothesis by measuring with resonant x - ray scattering the electronic level splittings in the a = y, eu systems, which we show to agree very well with ab initio electronic structure calculations. we find, however, that not distortions of iro6 - octahedra are the primary source for quenching the spin - orbit interaction, but strong long - range lattice anisotropies, which inevitably break the local cubic symmetry and will thereby be decisive in determining the system ' s topological ground state.
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arxiv:1212.4009
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unsupervised out - of - distribution ( ood ) detection aims to identify out - of - domain data by learning only from unlabeled in - distribution ( id ) training samples, which is crucial for developing a safe real - world machine learning system. current reconstruction - based methods provide a good alternative approach by measuring the reconstruction error between the input and its corresponding generative counterpart in the pixel / feature space. however, such generative methods face a key dilemma : improving the reconstruction power of the generative model while keeping a compact representation of the id data. to address this issue, we propose the diffusion - based layer - wise semantic reconstruction approach for unsupervised ood detection. the innovation of our approach is that we leverage the diffusion model ' s intrinsic data reconstruction ability to distinguish id samples from ood samples in the latent feature space. moreover, to set up a comprehensive and discriminative feature representation, we devise a multi - layer semantic feature extraction strategy. by distorting the extracted features with gaussian noise and applying the diffusion model for feature reconstruction, the separation of id and ood samples is implemented according to the reconstruction errors. extensive experimental results on multiple benchmarks built upon various datasets demonstrate that our method achieves state - of - the - art performance in terms of detection accuracy and speed. code is available at < https : / / github. com / xbyym / dlsr >.
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arxiv:2411.10701
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deep learning has been highly successful in some applications. nevertheless, its use for solving partial differential equations ( pdes ) has only been of recent interest with current state - of - the - art machine learning libraries, e. g., tensorflow or pytorch. physics - informed neural networks ( pinns ) are an attractive tool for solving partial differential equations based on sparse and noisy data. here extend pinns to solve obstacle - related pdes which present a great computational challenge because they necessitate numerical methods that can yield an accurate approximation of the solution that lies above a given obstacle. the performance of the proposed pinns is demonstrated in multiple scenarios for linear and nonlinear pdes subject to regular and irregular obstacles.
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arxiv:2304.03552
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the odd - frequency superconducting state appears generally in hybrid structures consisting of conventional superconductors and other materials, and features electrons that form temporally non - local cooper pairs. the quasiclassical theory of superconductivity has been extensively used to model such systems, finding in many cases excellent agreement with experimental measurements. therefore, it is of interest to study effective models of odd - frequency superconductivity to predict new phenomena associated with this form of unconventional pairing. we establish necessary criteria that the quasiclassical green functions in odd - frequency superconducting systems in the dirty limit must satisfy in order to be physically reasonable, including conservation of spectral weight. we show that it is possible to write down effective models which satisfy all the abovementioned criteria, but which still predict different behavior when it comes to the density of states and the magnetic response of the superconductor. for instance, an effective model for the odd - frequency anomalous green function that gives a conserved spectral weight can yield either a peaked or gapped density of states at the fermi energy, and exhibit conventional, zero, or unconventional meissner response. this finding demonstrates the importance of carefully considering the properties of effective models describing odd - frequency superconductivity in order to obtain physically reasonable results.
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arxiv:2212.00854
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by a well - known theorem of viterbo, the symplectic homology of the cotangent bundle of a closed manifold is isomorphic to the homology of its loop space. in this paper we extend the scope of this isomorphism in several directions. first, we give a direct definition of { \ em rabinowitz loop homology } in terms of morse theory on the loop space and prove that its product agrees with the pair - of - pants product on rabinowitz floer homology. the proof uses compactified moduli spaces of punctured annuli. second, we prove that, when restricted to { \ em positive } floer homology, resp. ~ loop space homology relative to the constant loops, the viterbo isomorphism intertwines various constructions of secondary pair - of - pants coproducts with the loop homology coproduct. third, we introduce { \ em reduced loop homology }, which is a common domain of definition for a canonical reduction of the loop product and for extensions of the loop homology coproduct which together define the structure of a commutative cocommutative unital infinitesimal anti - symmetric bialgebra. along the way, we show that the abbondandolo - schwarz quasi - isomorphism going from the floer complex of quadratic hamiltonians to the morse complex of the energy functional can be turned into a filtered chain isomorphism by using linear hamiltonians and the square root of the energy functional.
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arxiv:2008.13168
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an efficient technique to produce a periodic sequence of ultrashort pulses of recoilless gamma - radiation via its transmission through the optically thick vibrating resonant absorber was demonstrated recently [ nature, 508, 80 ( 2014 ) ]. in this work we extend the theoretical analysis to the case of a set of multiple absorbers. we consider an analytical model describing the control of spectral content of a frequency modulated gamma - radiation by selective correction of amplitudes and initial phases of some spectral components, using, respectively, the resonant absorption or dispersion of nuclei. on the basis of the analytical solutions we determine the ultimate possibilities of the proposed technique.
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arxiv:1501.00394
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spectral clustering is a powerful method for finding structure in a dataset through the eigenvectors of a similarity matrix. it often outperforms traditional clustering algorithms such as $ k $ - means when the structure of the individual clusters is highly non - convex. its accuracy depends on how the similarity between pairs of data points is defined. two important items contribute to the construction of the similarity matrix : the sparsity of the underlying weighted graph, which depends mainly on the distances among data points, and the similarity function. when a gaussian similarity function is used, the choice of the scale parameter $ \ sigma $ can be critical. in this paper we examine both items, the sparsity and the selection of suitable $ \ sigma $ ' s, based either directly on the graph associated to the dataset or on the minimal spanning tree ( mst ) of the graph. an extensive numerical experimentation on artificial and real - world datasets has been carried out to compare the performances of the methods.
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arxiv:1904.11352
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we introduce a new version of the fonll code, now capable of calculating differential distributions for top quark production with next - to - leading - log resummation of log ( p _ t / m ) terms. numerical results for lhc and fcc kinematics are presented. in the transverse momentum region presently explored by atlas and cms, no significant difference with respect to available fixed order predictions is predicted by fonll. the large transverse momentum resummation of fonll may instead become relevant if top is ever measured at transverse momentum scales of several tev.
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arxiv:1809.06626
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string compactifications typically require fluxes, for example in order to stabilise moduli. such fluxes, when they thread internal dimensions, are topological in nature and take on quantised values. this poses the puzzle as to how they could arise in the early universe, as they cannot be turned on incrementally. working with string inspired models in $ 6 $ and $ 8 $ dimensions, we show that there exist no - boundary solutions in which internal fluxes are present from the creation of the universe onwards. the no - boundary proposal can thus explain the origin of fluxes in a kaluza - klein context. in fact, it acts as a selection principle since no - boundary solutions are only found to exist when the fluxes have the right magnitude to lead to an effective potential that is positive and flat enough for accelerated expansion. within the range of selected fluxes, the no - boundary wave function assigns higher probability to smaller values of flux. our models illustrate how cosmology can act as a filter on a landscape of possible higher - dimensional solutions.
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arxiv:2209.08960
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we observed a two - step glass transition in monolayers of colloidal ellipsoids by video microscopy. the glass transition in the rotational degree of freedom was at a lower density than that in the translational degree of freedom. between the two transitions, ellipsoids formed an orientational glass. approaching the respective glass transitions, the rotational and translational fastest - moving particles in the supercooled liquid moved cooperatively and formed clusters with power - law size distributions. the mean cluster sizes diverge in power law as approaching the glass transitions. the clusters of translational and rotational fastest - moving ellipsoids formed mainly within pseudo - nematic domains, and around the domain boundaries, respectively.
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arxiv:1105.5760
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##eerx 10. 1. 1. 533. 7658. doi : 10. 1080 / 13501780801913298. s2cid 216137286. samuelson, paul a ; nordhaus, william d. ( 2010 ). economics. boston : irwin mcgraw - hill. isbn 978 - 0073511290. oclc 751033918. = = further reading = = anderson, david a. ( 2019 ). survey of economics. new york : worth. isbn 978 - 1 - 4292 - 5956 - 9. blanchard, olivier ; amighini, alessia ; giavazzi, francesco ( 2017 ). macroeconomics : a european perspective ( 3rd ed. ). pearson. isbn 978 - 1 - 292 - 08567 - 8. blaug, mark ( 1985 ). economic theory in retrospect ( 4th ed. ). cambridge : cambridge university press. isbn 978 - 0521316446. mccann, charles robert jr. ( 2003 ). the elgar dictionary of economic quotations. edward elgar. isbn 978 - 1840648201. post, louis f. ( 1927 ), the basic facts of economics : a common - sense primer for advanced students. united states : columbian printing company, incorporated. economics public domain audiobook at librivox. = = external links = = = = = general information = = = = = = institutions and organizations = = = = = = study resources = = =
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https://en.wikipedia.org/wiki/Economics
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abstract we present pac - bayesian bounds for the generalisation error of the k - nearest - neighbour classifier ( k - nn ). this is achieved by casting the k - nn classifier into a kernel space framework in the limit of vanishing kernel bandwidth. we establish a relation between prior measures over the coefficients in the kernel expansion and the induced measure on the weight vectors in kernel space. defining a sparse prior over the coefficients allows the application of a pac - bayesian folk theorem that leads to a generalisation bound that is a function of the number of redundant training examples : those that can be left out without changing the solution. the presented bound requires to quantify a prior belief in the sparseness of the solution and is evaluated after learning when the actual redundancy level is known. even for small sample size ( m ~ 100 ) the bound gives non - trivial results when both the expected sparseness and the actual redundancy are high.
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arxiv:2109.13889
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millimeter - wave self - backhauled small cells are a key component of next - generation wireless networks. their dense deployment will increase data rates, reduce latency, and enable efficient data transport between the access and backhaul networks, providing greater flexibility not previously possible with optical fiber. despite their high potential, operating dense self - backhauled networks optimally is an open challenge, particularly for radio resource management ( rrm ). this paper presents, radiorchestra, a holistic rrm framework that models and optimizes beamforming, rate selection as well as user association and admission control for self - backhauled networks. the framework is designed to account for practical challenges such as hardware limitations of base stations ( e. g., computational capacity, discrete rates ), the need for adaptability of backhaul links, and the presence of interference. our framework is formulated as a nonconvex mixed - integer nonlinear program, which is challenging to solve. to approach this problem, we propose three algorithms that provide a trade - off between complexity and optimality. furthermore, we derive upper and lower bounds to characterize the performance limits of the system. we evaluate the developed strategies in various scenarios, showing the feasibility of deploying practical self - backhauling in future networks.
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arxiv:2201.10297
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the stability of matter composed of electrons and static nuclei is investigated for a relativistic dynamics for the electrons given by a suitably projected dirac operator and with coulomb interactions. in addition there is an arbitrary classical magnetic field of finite energy. despite the previously known facts that ordinary nonrelativistic matter with magnetic fields, or relativistic matter without magnetic fields is already unstable when the fine structure constant, is too large it is noteworthy that the combination of the two is still stable provided the projection onto the positive energy states of the dirac operator, which defines the electron, is chosen properly. a good choice is to include the magnetic field in the definition. a bad choice, which always leads to instability, is the usual one in which the positive energy states are defined by the free dirac operator. both assertions are proved here.
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arxiv:cond-mat/9610195
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a new breed of web application, dubbed ajax, is emerging in response to a limited degree of interactivity in large - grain stateless web interactions. at the heart of this new approach lies a single page interaction model that facilitates rich interactivity. we have studied and experimented with several ajax frameworks trying to understand their architectural properties. in this paper, we summarize three of these frameworks and examine their properties and introduce the spiar architectural style. we describe the guiding software engineering principles and the constraints chosen to induce the desired properties. the style emphasizes user interface component development, and intermediary delta - communication between client / server components, to improve user interactivity and ease of development. in addition, we use the concepts and principles to discuss various open issues in ajax frameworks and application development.
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arxiv:cs/0608111
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it is shown that transient spin - spin correlations in one - dimensional spin s > > 1 chain can be enhanced for initially factorized and individually squeezed spin states. such correlation transfer form " internal " to " external " degrees of freedom can be well described by using a semiclassical phase - space approach.
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arxiv:1605.09476
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we report here on the first pointed x - ray observation of the supernova remnant ( snr ) g330. 2 + 1. 0. the x - ray morphology is characterized by an extended shell. its x - ray spectrum is well represented by a single power - law function with a photon index of $ \ gamma \ simeq 2. 8 $ and interstellar absorption of $ n _ { \ rm h } \ simeq2. 6 \ times 10 ^ { 22 } $ [ cm $ ^ { - 2 } $ ]. we interpret this emission as synchrotron radiation from accelerated electrons at the snr shock, as seen in sn 1006. the surface brightness of the x - ray emission is anti - correlated with the radio emission, and the power - law spectrum is dominated at the western shell where the radio emission is weak. the co - existence of two distinct ( radio bright / x - ray faint and radio faint / x - ray bright ) shells in a single supernova remnant challenges our understanding of the particle acceleration and radiation mechanisms in different interstellar environments. the object may be a good target for searching tev gamma - rays and molecular gas surrounding the blast shock. we also report on the nature of a bright point - like source ( ax j1601 - 5143 ) to the south of the snr.
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arxiv:astro-ph/0601569
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we provide an analytical characterization of the model flexibility of the synthetic control method ( scm ) in the familiar form of degrees of freedom. we obtain estimable information criteria. these may be used to circumvent cross - validation when selecting either the weighting matrix in the scm with covariates, or the tuning parameter in model averaging or penalized variants of scm. we assess the impact of car license rationing in tianjin and make a novel use of scm ; while a natural match is available, it and other donors are noisy, inviting the use of scm to average over approximately matching donors. the very large number of candidate donors calls for model averaging or penalized variants of scm and, with short pre - treatment series, model selection per information criteria outperforms that per cross - validation.
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arxiv:2207.02943
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there is growing interest in learning fourier domain sampling strategies ( particularly for magnetic resonance imaging, mri ) using optimization approaches. for non - cartesian sampling patterns, the system models typically involve non - uniform fft ( nufft ) operations. commonly used nufft algorithms contain frequency domain interpolation, which is not differentiable with respect to the sampling pattern, complicating the use of gradient methods. this paper describes an efficient and accurate approach for computing approximate gradients involving nuffts. multiple numerical experiments validated the improved accuracy and efficiency of the proposed approximation. as an application to computational imaging, the nufft jacobians were used to optimize non - cartesian mri sampling trajectories via data - driven stochastic optimization. specifically, the sampling patterns were learned with respect to various model - based reconstruction algorithms, including quadratic regularized reconstruction and compressed sensing - based reconstruction. the proposed approach enables sampling optimization for image sizes that are infeasible with standard auto - differentiation methods due to memory limits. the synergistic acquisition and reconstruction lead to remarkably improved image quality. in fact, we show that model - based image reconstruction ( mbir ) methods with suitably optimized imaging parameters can perform nearly as well as cnn - based methods.
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arxiv:2111.02912
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to probe the initial conditions for high - mass star and cluster formation, we investigate the properties of dense filaments within the infrared dark cloud g035. 39 - 00. 33 ( irdc g035. 39 ) in a combined very large array ( vla ) and the green bank telescope ( gbt ) mosaic tracing the nh3 ( 1, 1 ) and ( 2, 2 ) emission down to 0. 08 pc scales. using agglomerative hierarchical clustering on multiple line - of - sight velocity component fitting results, we identify seven extended velocity - coherent components in our data, likely representing spatially coherent physical structures, some exhibiting complex gas motions. the velocity gradient magnitude distribution peaks at its mode of 0. 35 km / s / pc and has a long tail extending into higher values of 1. 5 - 2 km / s / pc, and is generally consistent with those found toward the same cloud in other molecular tracers and with the values found towards nearby low - mass dense cloud cores at the same scales. contrary to observational and theoretical expectations, we find the non - thermal ammonia line widths to be systematically narrower ( by about 20 % ) than those of n2h + ( 1 - 0 ) line transition observed with similar resolution. if the observed ordered velocity gradients represent the core envelope solid - body rotation, we estimate the specific angular momentum to be about 2 x 10 ^ 21 cm ^ 2 / s, similar to the low - mass star - forming cores. together with the previous finding of subsonic motions in g035. 39, our results demonstrate high levels of similarity between kinematics of a high - mass star - forming irdc and the low - mass star formation regime.
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arxiv:1812.09581
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spontaneous subtle emotions are expressed through micro - expressions, which are tiny, sudden and short - lived dynamics of facial muscles ; thus poses a great challenge for visual recognition. the abrupt but significant dynamics for the recognition task are temporally sparse while the rest, irrelevant dynamics, are temporally redundant. in this work, we analyze and enforce sparsity constrains to learn significant temporal and spectral structures while eliminate irrelevant facial dynamics of micro - expressions, which would ease the challenge in the visual recognition of spontaneous subtle emotions. the hypothesis is confirmed through experimental results of automatic spontaneous subtle emotion recognition with several sparsity levels on casme ii and smic, the only two publicly available spontaneous subtle emotion databases. the overall performances of the automatic subtle emotion recognition are boosted when only significant dynamics are preserved from the original sequences.
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arxiv:1601.04805
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we propose a new single - shot method for multi - person 3d pose estimation in general scenes from a monocular rgb camera. our approach uses novel occlusion - robust pose - maps ( orpm ) which enable full body pose inference even under strong partial occlusions by other people and objects in the scene. orpm outputs a fixed number of maps which encode the 3d joint locations of all people in the scene. body part associations allow us to infer 3d pose for an arbitrary number of people without explicit bounding box prediction. to train our approach we introduce muco - 3dhp, the first large scale training data set showing real images of sophisticated multi - person interactions and occlusions. we synthesize a large corpus of multi - person images by compositing images of individual people ( with ground truth from mutli - view performance capture ). we evaluate our method on our new challenging 3d annotated multi - person test set mupots - 3d where we achieve state - of - the - art performance. to further stimulate research in multi - person 3d pose estimation, we will make our new datasets, and associated code publicly available for research purposes.
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arxiv:1712.03453
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we study the effects of heterostrain on moir \ ' e bands in twisted bilayer graphene and bilayer transition metal dichalcogenide ( tmd ) systems. for bilayer graphene with twist angle near $ 1 ^ \ circ $, we show that heterostrain significantly increases the energy separation between conduction and valence bands as well as the dirac velocity at charge neutrality, which resolves several puzzles in scanning tunneling spectroscopy and quantum oscillation experiments at once. for bilayer tmd, we show that applying small heterostrain generally leads to flat moir \ ' e bands that are highly tunable.
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arxiv:1902.10146
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let $ g $ be graph with vertex set $ v $ and order $ n = | v | $. a coalition in $ g $ is a combination of two distinct sets, $ a \ subseteq v $ and $ b \ subseteq v $, which are disjoint and are not dominating sets of $ g $, but $ a \ cup b $ is a dominating set of $ g $. a coalition partition of $ g $ is a partition $ \ mathcal { p } = \ { s _ 1, \ ldots, s _ k \ } $ of its vertex set $ v $, where each set $ s _ i \ in \ mathcal { p } $ is either a dominating set of $ g $ with only one vertex, or it is not a dominating set but forms a coalition with some other set $ s _ j \ in \ mathcal { p } $. the coalition number $ c ( g ) $ is the maximum cardinality of a coalition partition of $ g $. to represent a coalition partition $ \ mathcal { p } $ of $ g $, a coalition graph $ \ cg ( g, \ mathcal { p } ) $ is created, where each vertex of the graph corresponds to a member of $ \ mathcal { p } $ and two vertices are adjacent if and only if their corresponding sets form a coalition in $ g $. a coalition partition $ \ mathcal { p } $ of $ g $ is a singleton coalition partition if every set in $ \ mathcal { p } $ consists of a single vertex. if a graph $ g $ has a singleton coalition partition, then $ g $ is referred to as a singleton - partition graph. a graph $ h $ is called a singleton coalition graph of a graph $ g $ if there exists a singleton coalition partition $ \ mathcal { p } $ of $ g $ such that the coalition graph $ \ cg ( g, \ mathcal { p } ) $ is isomorphic to $ h $. a singleton coalition graph chain with an initial graph $ g _ 1 $ is defined as the sequence $ g _ 1 \ rightarrow g _ 2 \ rightarrow g _ 3 \ rightarrow \ cdots $ where all graphs $ g _ i $ are singleton - partition graphs, and $ \ cg ( g _ i, \ gamma _ 1 ) = g _ { i + 1 } $, where $ \ gamma _ 1 $ represents a singleton coalition partition
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arxiv:2304.07606
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we present a bayesian graph neural network ( bgnn ) that can estimate the weak lensing convergence ( $ \ kappa $ ) from photometric measurements of galaxies along a given line of sight. the method is of particular interest in strong gravitational time delay cosmography ( tdc ), where characterizing the " external convergence " ( $ \ kappa _ { \ rm ext } $ ) from the lens environment and line of sight is necessary for precise inference of the hubble constant ( $ h _ 0 $ ). starting from a large - scale simulation with a $ \ kappa $ resolution of $ \ sim $ 1 $ ' $, we introduce fluctuations on galaxy - galaxy lensing scales of $ \ sim $ 1 $ ' ' $ and extract random sightlines to train our bgnn. we then evaluate the model on test sets with varying degrees of overlap with the training distribution. for each test set of 1, 000 sightlines, the bgnn infers the individual $ \ kappa $ posteriors, which we combine in a hierarchical bayesian model to yield constraints on the hyperparameters governing the population. for a test field well sampled by the training set, the bgnn recovers the population mean of $ \ kappa $ precisely and without bias, resulting in a contribution to the $ h _ 0 $ error budget well under 1 \ %. in the tails of the training set with sparse samples, the bgnn, which can ingest all available information about each sightline, extracts more $ \ kappa $ signal compared to a simplified version of the traditional method based on matching galaxy number counts, which is limited by sample variance. our hierarchical inference pipeline using bgnns promises to improve the $ \ kappa _ { \ rm ext } $ characterization for precision tdc. the implementation of our pipeline is available as a public python package, node to joy.
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arxiv:2211.07807
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this paper presents crest, a prototype front - end tool intended as an add - on to commercial eda formal verifcation environments. crest is an adaptation of the cbmc bounded model checker for c, an academic tool widely used in industry for software analysis and property verification. it leverages the capabilities of cbmc to process hardware datapath specifications written in arbitrary ansi - c, without limiting restrictions to a synthesizable subset. we briefly sketch the architecture of our tool and show its use in a range of verification case studies.
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arxiv:1908.01324
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in this short review, we discuss the approach of the commutator algebra of covariant derivative to analyse the gravitational theories, starting from the standard einstein ' s general theory of relativity and focusing on the rastall theory. after that, we discuss the important role of the torsion in this mathematical framework. in the appendix of the paper we analyse the importance of the nascent gravitational wave astronomy as a tool to discriminate among the general theory of relativity and alternative theories of gravity.
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arxiv:1706.06863
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we have performed an angle - resolved photoemission study of the nodal quasi - particle spectra of the high - tc cuprate tri - layer bi2sr2ca2cu3o10 + d ( tc ~ 110 k ). the spectral weight z of the nodal quasi - particle increases with decreasing temperature across the tc. such a temperature dependence is qualitatively similar to that of the coherence peak intensity in the anti nodal region of various high - tc cuprates although the nodal spectral weight remains finite and large above tc. we attribute this observation to the reduction of electron correlation strength in going from the normal metallic state to the superconducting state, a characteristic behavior of a superconductor with strong electron correlation.
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arxiv:1510.00176
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modelling randomness in shape data, for example, the evolution of shapes of organisms in biology, requires stochastic models of shapes. this paper presents a new stochastic shape model based on a description of shapes as functions in a sobolev space. using an explicit orthonormal basis as a reference frame for the noise, the model is independent of the parameterisation of the mesh. we define the stochastic model, explore its properties, and illustrate examples of stochastic shape evolutions using the resulting numerical framework.
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arxiv:2302.05382
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we aim at addressing the questions related to galaxy mass assembly through major and minor wet merging processes in the redshift range 1 < z < 2. a consequent fraction of milky way like galaxies are thought to have undergone an unstable clumpy phase at this early stage. using the adaptive mesh refinement code ramses, with a recent physically - motivated implementation of stellar feedback, we build the merging and isolated high - redshift adaptive mesh refinement galaxies ( mirage ) sample. it is composed of 20 mergers and 3 isolated idealized disks simulations with global physical properties in accordance with the 1 < z < 2 mass complete sample massiv. the numerical hydrodynamical resolution reaches 7 parsecs in the smallest eulerian cells. our simulations include : star formation, metal line cooling, metallicity advection, and a recent implementation of stellar feedback which encompasses ob - type stars radiative pressure, photo - ionization heating, and supernovae. the initial conditions are set to match the z ~ 2 observations, thanks to a new public code dice. the numerical resolution allows us to follow the formation and evolution of giant clumps formed in - situ from jeans instabilities triggered by high initial gas fraction. the star formation history of isolated disks shows stochastic star formation rate, which proceeds from the complex behavior of the giant clumps. our minor and major gas - rich merger simulations do not trigger starbursts, suggesting a saturation of the star formation in a turbulent and clumpy interstellar medium fed by substantial accretion from the circum - galactic medium. our simulations are close to the normal regime of the disk - like star formation on a schmidt - kennicutt diagram. the mass - size relation and its rate of evolution matches observations, suggesting that the inside - out growth mechanisms of the stellar disk do not necessarily require to be achieved through a cold accretion.
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arxiv:1307.7130
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we have recently used inelastic neutron scattering to measure the magnetic excitation spectrum of la ( 1. 875 ) ba ( 0. 125 ) cuo ( 4 ) up to 200 mev. this particular cuprate is of interest because it exhibits static charge and spin stripe order. the observed spectrum is remarkably similar to that found in superconducting yba ( 2 ) cu ( 3 ) o ( 6 + x ) and la ( 2 - x ) sr ( x ) cuo ( 4 ) ; the main differences are associated with the spin gap. we suggest that essentially all observed features of the magnetic scattering from cuprate superconductors can be described by a universal magnetic excitation spectrum multiplied by a spin gap function with a material - dependent spin - gap energy.
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arxiv:cond-mat/0411082
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we develop the notion of a ( pro - ) conformal pseudo operad and apply it to the construction of the basic cohomology complex of a vertex algebra. the paper heavily uses the ideas and constructions of the work of tamarkin [ tam02 ]
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arxiv:2407.05725
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we study the holographic duals of type ii and heterotic matrix string theories described by warped ads _ 3 supergravities. by explicitly solving the linearized equations of motion around near horizon d - string geometries, we determine the spectrum of kaluza - klein primaries for type i, ii supergravities on warped ads _ 3 x s ^ 7. the results match those coming from the dual two - dimensional gauge theories living on the d - string worldvolumes. we briefly discuss the connections with the n = ( 8, 8 ), n = ( 8, 0 ) orbifold superconformal field theories to which type iib / heterotic matrix strings flow in the infrared. in particular, we associate the dimension ( 3 / 2, 3 / 2 ) twisted operator which brings the matrix string theories out from the conformal point ( r ^ 8 ) ^ n / s _ n with the dilaton profile in the supergravity background. the familiar dictionary between masses and scaling dimensions of fields and operators are modified by the presence of non - trivial warp factors and running dilatons. these modifications are worked out for the general case of domain wall / qft correspondences between supergravities on warped ads _ { d + 1 } x s ^ q geometries and super yang - mills theories with 16 supercharges.
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arxiv:hep-th/0206247
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particle swarm optimization ( pso ) has demonstrated efficacy in addressing static path planning problems. nevertheless, such application on dynamic scenarios has been severely precluded by pso ' s low computational efficiency and premature convergence downsides. to address these limitations, we proposed a tensor operation form ( tof ) that converts particle - wise manipulations to tensor operations, thereby enhancing computational efficiency. harnessing the computational advantage of tof, a variant of pso, designated as self - evolving particle swarm optimization ( sepso ) was developed. the sepso is underpinned by a novel hierarchical self - evolving framework ( hsef ) that enables autonomous optimization of its own hyper - parameters to evade premature convergence. additionally, a priori initialization ( pi ) mechanism and an auto truncation ( at ) mechanism that substantially elevates the real - time performance of sepso on dynamic path planning problems were introduced. comprehensive experiments on four widely used benchmark optimization functions have been initially conducted to corroborate the validity of sepso. following this, a dynamic simulation environment that encompasses moving start / target points and dynamic / static obstacles was employed to assess the effectiveness of sepso on the dynamic path planning problem. simulation results exhibit that the proposed sepso is capable of generating superior paths with considerably better real - time performance ( 67 path planning computations per second in a regular desktop computer ) in contrast to alternative methods. the code and video of this paper can be accessed here.
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arxiv:2308.10169
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in programming language theory and type theory, polymorphism is the use of one symbol to represent multiple different types. in object - oriented programming, polymorphism is the provision of one interface to entities of different data types. the concept is borrowed from a principle in biology where an organism or species can have many different forms or stages. the most commonly recognized major forms of polymorphism are : ad hoc polymorphism : defines a common interface for an arbitrary set of individually specified types. parametric polymorphism : not specifying concrete types and instead use abstract symbols that can substitute for any type. subtyping ( also called subtype polymorphism or inclusion polymorphism ) : when a name denotes instances of many different classes related by some common superclass. = = history = = interest in polymorphic type systems developed significantly in the 1990s, with practical implementations beginning to appear by the end of the decade. ad hoc polymorphism and parametric polymorphism were originally described in christopher strachey ' s fundamental concepts in programming languages, where they are listed as " the two main classes " of polymorphism. ad hoc polymorphism was a feature of algol 68, while parametric polymorphism was the core feature of ml ' s type system. in a 1985 paper, peter wegner and luca cardelli introduced the term inclusion polymorphism to model subtypes and inheritance, citing simula as the first programming language to implement it. = = forms = = = = = ad hoc polymorphism = = = christopher strachey chose the term ad hoc polymorphism to refer to polymorphic functions that can be applied to arguments of different types, but that behave differently depending on the type of the argument to which they are applied ( also known as function overloading or operator overloading ). the term " ad hoc " in this context is not pejorative : instead, it means that this form of polymorphism is not a fundamental feature of the type system. in the java example below, the add functions seem to work generically over two types ( integer and string ) when looking at the invocations, but are considered to be two entirely distinct functions by the compiler for all intents and purposes : in dynamically typed languages the situation can be more complex as the correct function that needs to be invoked might only be determinable at run time. implicit type conversion has also been defined as a form of polymorphism, referred to as " coercion polymorphism ". = = = parametric polymorphism = = = parametric polymorphism allows a function
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https://en.wikipedia.org/wiki/Polymorphism_(computer_science)
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strain - mediated magnetoelectric ( me ) coupling in ferroelectric ( fe ) / ferromagnetic ( fm ) heterostructures offers a unique opportunity for both fundamental scientific research and low power multifunctional devices. relaxor - ferroelectrics, like ( 1 - x ) pb ( mg1 / 3nb2 / 3 ) o3 - ( x ) pbtio3 ( pmn - xpt ), are ideal fe layer candidates due to their giant piezoelectricity. but thin films of pmn - pt suffer from substrate clamping which substantially reduces piezoelectric in - plane strains. here we present the first demonstration of low voltage me coupling in an all - thin - film heterostructure which utilizes the anisotropic strains induced by the ( 011 ) orientation of pmn - pt. we completely remove pmn - pt films from their substrate and couple with fm ni overlayers to create membrane pmn - pt / ni heterostructures showing 90 degree ni magnetization rotation with 3v pmn - pt bias, much less than the bulk pmnpt ~ 100v requirement. scanning transmission electron microscopy and phase - field simulations clarify the membrane response. these results provide a crucial step towards understanding the microstructural behavior of pmn - pt thin films for use in piezo - driven magnetoelectric heterostructures.
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arxiv:2110.05581
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we compare the radial profiles of the specific star formation rate ( ssfr ) in a sample of 169 star - forming galaxies in close pairs with those of mass - matched control galaxies in the sdss - iv manga survey. we find that the ssfr is centrally enhanced ( within one effective radius ) in interacting galaxies by ~ 0. 3 dex and that there is a weak ssfr suppression in the outskirts of the galaxies of ~ 0. 1 dex. we stack the differences profiles for galaxies in five stellar mass bins between log ( m / mstar ) = 9. 0 - 11. 5 and find that the ssfr enhancement has no dependence on the stellar mass. the same result is obtained when the comparison galaxies are matched to each paired galaxy in both stellar mass and redshift. in addition, we find that that the ssfr enhancement is elevated in pairs with nearly equal masses and closer projected separations, in agreement with previous work based on single - fiber spectroscopy. we also find that the ssfr offsets in the outskirts of the paired galaxies are dependent on whether the galaxy is the more massive or less massive companion in the pair. the more massive companion experiences zero to a positive ssfr enhancement while the less massive companion experiences ssfr suppression in their outskirts. our results illustrate the complex tidal effects on star formation in closely paired galaxies.
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arxiv:2102.03398
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undisputedly, derivation of theoretical systematic uncertainties is an inseparable ingredient of any robust analysis dealing with experimental data. however, it is not uncommon, even for those analyses that use state of the art methods and tools to suffer from insufficient statistics when it comes to the simulated datasets used to estimate systematic uncertainties. this practically limits the power, and sometimes the robustness of the analysis. in this paper, we present syscalc, a code which is able to derive weights for various important theoretical systematic uncertainties, including those related to the choice of the parton distribution function sets and the various scale choices. syscalc utilizes the central sample generated events to estimate the related systematic uncertainties, thus, omitting the need for generating dedicated systematics datasets, and with only a minimal added cost in terms of computing resources. in this paper we discuss the working principles of the code accompanied by various validation plots. we also discuss the structure of the code followed by a practical guide for how to use the tool.
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arxiv:1801.08401
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disentanglement learning is crucial for obtaining disentangled representations and controllable generation. current disentanglement methods face several inherent limitations : difficulty with high - resolution images, primarily focusing on learning disentangled representations, and non - identifiability due to the unsupervised setting. to alleviate these limitations, we design new architectures and loss functions based on stylegan ( karras et al., 2019 ), for semi - supervised high - resolution disentanglement learning. we create two complex high - resolution synthetic datasets for systematic testing. we investigate the impact of limited supervision and find that using only 0. 25 % ~ 2. 5 % of labeled data is sufficient for good disentanglement on both synthetic and real datasets. we propose new metrics to quantify generator controllability, and observe there may exist a crucial trade - off between disentangled representation learning and controllable generation. we also consider semantic fine - grained image editing to achieve better generalization to unseen images.
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arxiv:2003.03461
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we study density waves in the flows of granular particles through vertical tubes and hoppers using both analytic methods and molecular dynamics ( md ) simulations. we construct equations of motion for quasi one - dimensional systems. the equations, combined with the bagnold ' s law for friction, are used to describe the time evolutions of the density and the velocity fields for narrow tubes and hoppers. the solutions of the equations can have two types of density waves, kinetic and dynamic. for tubes, we can show the existence of kinetic waves, and obtain the condition for dynamic waves for tubes from the equations. for hoppers, we obtain the solutions of the equations up to the first order of the opening angle, which also show the existence of kinetic waves. we reproduce density waves in the md simulations for tubes. the waves are believed to be kinetic based on a few evidences, including a well defined flux - density curve. in md simulations of flows in hoppers, we find density waves, which are also believed to be kinetic.
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arxiv:cond-mat/9306052
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intense competition from media vision at the high end and aztech at the low end. sorkin, in particular, dramatically strengthened the company ' s brand position through crisp licensing and an aggressive defense of creative ' s intellectual property positions while working to shorten product development cycles. at the same time, esber and the original founders of the company had differences of opinion on the strategy and positioning of the company. esber exited in 1995, followed quickly by buchanan and pomerantz. following esber ' s departure, sorkin was promoted to general manager of audio and communication products and later executive vice - president of business development and corporate investments, before leaving creative in 1996 to run elon musk ' s first startup and internet pioneer zip2. by 1996, creative ' s revenues had peaked at us $ 1. 6 billion. with pioneering investments in voip and media streaming, creative was well - positioned to take advantage of the internet era, but ventured into the cd - rom market and was eventually forced to write off nearly us $ 100 million in inventory when the market collapsed due to a flood of cheaper alternatives. = = = 1997 – 2011 = = = the firm had maintained a strong foothold in the isa pc audio market until 14 july 1997 when aureal semiconductor entered the soundcard market with their very competitive pci au8820 vortex 3d sound technology. the firm at the time was in development of their own in house pci audio cards but were finding little success adopting the pci standard. in january 1998 in order to quickly facilitate a working pci audio technology, the firm made the acquisition of ensoniq for us $ 77 million. on 5 march 1998 the firm sued aureal with patent infringement claims over a midi caching technology held by e - mu systems. aureal filed a counterclaim stating the firm was intentionally interfering with its business prospects, had defamed them, commercially disparaged, engaged in unfair competition with intent to slow down aureals sales, and acted fraudulently. the suit had come only days after aureal gained a fair market with the au8820 vortex1. in august 1998, the sound blaster live! was the firm ' s first sound card developed for the pci bus in order to compete with upcoming aureal au8830 vortex2 sound chip. aureal at this time were making fliers comparing their new au8830 chips to the now shipping sound blaster live!. the specifications within these fliers comparing the au8830 to the sound blast
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https://en.wikipedia.org/wiki/Creative_Technology
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this paper begins with a general theory of error in cross - validation testing of algorithms for supervised learning from examples. it is assumed that the examples are described by attribute - value pairs, where the values are symbolic. cross - validation requires a set of training examples and a set of testing examples. the value of the attribute that is to be predicted is known to the learner in the training set, but unknown in the testing set. the theory demonstrates that cross - validation error has two components : error on the training set ( inaccuracy ) and sensitivity to noise ( instability ). this general theory is then applied to voting in instance - based learning. given an example in the testing set, a typical instance - based learning algorithm predicts the designated attribute by voting among the k nearest neighbors ( the k most similar examples ) to the testing example in the training set. voting is intended to increase the stability ( resistance to noise ) of instance - based learning, but a theoretical analysis shows that there are circumstances in which voting can be destabilizing. the theory suggests ways to minimize cross - validation error, by insuring that voting is stable and does not adversely affect accuracy.
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arxiv:cs/0212030
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2466 decimal digits long. a boolean type is a type that can represent only two values : 0 and 1, usually identified with false and true respectively. this type can be stored in memory using a single bit, but is often given a full byte for convenience of addressing and speed of access. a four - bit quantity is known as a nibble ( when eating, being smaller than a bite ) or nybble ( being a pun on the form of the word byte ). one nibble corresponds to one digit in hexadecimal and holds one digit or a sign code in binary - coded decimal. = = = bytes and octets = = = the term byte initially meant ' the smallest addressable unit of memory '. in the past, 5 -, 6 -, 7 -, 8 -, and 9 - bit bytes have all been used. there have also been computers that could address individual bits ( ' bit - addressed machine ' ), or that could only address 16 - or 32 - bit quantities ( ' word - addressed machine ' ). the term byte was usually not used at all in connection with bit - and word - addressed machines. the term octet always refers to an 8 - bit quantity. it is mostly used in the field of computer networking, where computers with different byte widths might have to communicate. in modern usage byte almost invariably means eight bits, since all other sizes have fallen into disuse ; thus byte has come to be synonymous with octet. = = = words = = = the term ' word ' is used for a small group of bits that are handled simultaneously by processors of a particular architecture. the size of a word is thus cpu - specific. many different word sizes have been used, including 6 -, 8 -, 12 -, 16 -, 18 -, 24 -, 32 -, 36 -, 39 -, 40 -, 48 -, 60 -, and 64 - bit. since it is architectural, the size of a word is usually set by the first cpu in a family, rather than the characteristics of a later compatible cpu. the meanings of terms derived from word, such as longword, doubleword, quadword, and halfword, also vary with the cpu and os. practically all new desktop processors are capable of using 64 - bit words, though embedded processors with 8 - and 16 - bit word size are still common. the 36 - bit word length was common in the early days of computers. one important cause of non - portability of software
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https://en.wikipedia.org/wiki/Integer_(computer_science)
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we propose high - order hypergraph walks as a framework to generalize graph - based network science techniques to hypergraphs. edge incidence in hypergraphs is quantitative, yielding hypergraph walks with both length and width. graph methods which then generalize to hypergraphs include connected component analyses, graph distance - based metrics such as closeness centrality, and motif - based measures such as clustering coefficients. we apply high - order analogs of these methods to real world hypernetworks, and show they reveal nuanced and interpretable structure that cannot be detected by graph - based methods. lastly, we apply three generative models to the data and find that basic hypergraph properties, such as density and degree distributions, do not necessarily control these new structural measurements. our work demonstrates how analyses of hypergraph - structured data are richer when utilizing tools tailored to capture hypergraph - native phenomena, and suggests one possible avenue towards that end.
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arxiv:1906.11295
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for bayesian learning, given likelihood function and gaussian prior, the elliptical slice sampler, introduced by murray, adams and mackay 2010, provides a tool for the construction of a markov chain for approximate sampling of the underlying posterior distribution. besides of its wide applicability and simplicity its main feature is that no tuning is necessary. under weak regularity assumptions on the posterior density we show that the corresponding markov chain is geometrically ergodic and therefore yield qualitative convergence guarantees. we illustrate our result for gaussian posteriors as they appear in gaussian process regression, as well as in a setting of a multi - modal distribution. remarkably, our numerical experiments indicate a dimension - independent performance of elliptical slice sampling even in situations where our ergodicity result does not apply.
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arxiv:2105.03308
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the paper develops no arbitrage results for trajectory based models by imposing general constraints on the trading portfolios. the main condition imposed, in order to avoid arbitrage opportunities, is a local continuity requirement on the final portfolio value considered as a functional on the trajectory space. the paper shows this to be a natural requirement by proving that a large class of practical trading strategies, defined by means of trajectory based stopping times, give rise to locally continuous functionals. the theory is illustrated, with some detail, for two specific trajectory models of practical interest. the implications for stochastic models which are not semimartingales are described. the present paper extends some of the results in [ 1 ] by incorporating in the formalism a larger set of trading portfolios.
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arxiv:1403.5685
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scholarly usage data holds the potential to be used as a tool to study the dynamics of scholarship in real time, and to form the basis for the definition of novel metrics of scholarly impact. however, the formal groundwork to reliably and validly exploit usage data is lacking, and the exact nature, meaning and applicability of usage - based metrics is poorly understood. the mesur project funded by the andrew w. mellon foundation constitutes a systematic effort to define, validate and cross - validate a range of usage - based metrics of scholarly impact. mesur has collected nearly 1 billion usage events as well as all associated bibliographic and citation data from significant publishers, aggregators and institutional consortia to construct a large - scale usage data reference set. this paper describes some major challenges related to aggregating and processing usage data, and discusses preliminary results obtained from analyzing the mesur reference data set. the results confirm the intrinsic value of scholarly usage data, and support the feasibility of reliable and valid usage - based metrics of scholarly impact.
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arxiv:0804.3791
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we prove area inequalities for stable marginally outer trapped surfaces in einstein - maxwell - dilaton theory. our inspiration comes on the one hand from a corresponding upper bound for the area in terms of the charges obtained recently by dain, jaramillo and reiris [ 1 ] in the pure einstein - maxwell case without symmetries, and on the other hand from yazadjiev ' s inequality [ 2 ] in the axially symmetric einstein - maxwell - dilaton case. the common issue in these proofs and in the present one is a functional $ { \ mathscr w } $ of the matter fields for which the stability condition readily yields an { \ it upper } bound. on the other hand, the step which crucially depends on whether or not a dilaton field is present is to obtain a { \ it lower } bound for $ { \ mathscr w } $ as well. we obtain the latter by first setting up a variational principle for $ { \ mathscr w } $ with respect to the dilaton field $ \ phi $, then by proving existence of a minimizer $ \ psi $ as solution of the corresponding euler - lagrange equations and finally by estimating $ { \ mathscr w } ( \ psi ) $. in the special case that the normal components of the electric and magnetic fields are proportional we obtain the area bound $ a \ ge 8 \ pi p q $ in terms of the electric and magnetic charges. in the generic case our results are less explicit but imply rigorous ` perturbation ' results for the above inequality. all our inequalities are saturated for a 2 - parameter family of static, extreme solutions found by gibbons [ 3 ]. via the bekenstein - hawking relation $ a = 4s $ our results give positive lower bounds for the entropy $ s $ which are particularly interesting in the einstein - maxwell - dilaton case.
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arxiv:1308.3659
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large vision - language models ( lvlms ) have recently played a dominant role in multimodal vision - language learning. despite the great success, it lacks a holistic evaluation of their efficacy. this paper presents a comprehensive evaluation of publicly available large multimodal models by building a lvlm evaluation hub ( lvlm - ehub ). our lvlm - ehub consists of $ 8 $ representative lvlms such as instructblip and minigpt - 4, which are thoroughly evaluated by a quantitative capability evaluation and an online arena platform. the former evaluates $ 6 $ categories of multimodal capabilities of lvlms such as visual question answering and embodied artificial intelligence on $ 47 $ standard text - related visual benchmarks, while the latter provides the user - level evaluation of lvlms in an open - world question - answering scenario. the study reveals several innovative findings. first, instruction - tuned lvlm with massive in - domain data such as instructblip heavily overfits many existing tasks, generalizing poorly in the open - world scenario. second, instruction - tuned lvlm with moderate instruction - following data may result in object hallucination issues ( i. e., generate objects that are inconsistent with target images in the descriptions ). it either makes the current evaluation metric such as cider for image captioning ineffective or generates wrong answers. third, employing a multi - turn reasoning evaluation framework can mitigate the issue of object hallucination, shedding light on developing an effective pipeline for lvlm evaluation. the findings provide a foundational framework for the conception and assessment of innovative strategies aimed at enhancing zero - shot multimodal techniques. our lvlm - ehub will be available at https : / / github. com / opengvlab / multi - modality - arena
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arxiv:2306.09265
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an $ f $ - structure, introduced by k. yano in 1963 and subsequently studied by a number of geometers, is a higher dimensional analog of almost complex and almost contact structures, defined by a ( 1, 1 ) - tensor field $ f $ on a $ ( 2n + p ) $ - dimensional manifold, which satisfies $ f ^ 3 + f = 0 $ and has constant rank $ 2n $. we recently introduced the weakened ( globally framed ) $ f $ - structure ( i. e., the complex structure on $ f ( tm ) $ is replaced by a nonsingular skew - symmetric tensor ) and its subclasses of weak $ k $ -, $ { \ cal s } $ -, and $ { \ cal c } $ - structures on riemannian manifolds with totally geodesic foliations, which allow us to take a fresh look at the classical theory. we demonstrate this by generalizing several known results on globally framed $ f $ - manifolds. first, we express the covariant derivative of $ f $ using a new tensor on a metric weak $ f $ - structure, then we prove that on a weak $ k $ - manifold the characteristic vector fields are killing and $ \ ker f $ defines a totally geodesic foliation, an $ { \ cal s } $ - structure is rigid, i. e., our weak $ { \ cal s } $ - structure is an $ { \ cal s } $ - structure, and a metric weak $ f $ - structure with parallel tensor $ f $ reduces to a weak $ { \ cal c } $ - structure. for $ p = 1 $ we obtain the corresponding corollaries for weak almost contact, weak cosymplectic, and weak sasakian structures.
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arxiv:2205.02158
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we study a function field version of a classical problem concerning square - free values of polynomials evaluated at primes. we show that for a square - free polynomial $ f \ in \ mathbb { f } _ q [ t ] [ x ] $, there is a limiting density as $ n \ to \ infty $ of primes $ p \ in \ mathbb { f } _ q [ t ] $ of degree $ n $ such that $ f ( p ) $ is square - free. over the integers the analogous result is only known when all irreducible factors of $ f $ have degree at most 3.
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arxiv:1409.7633
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with the advent of advanced multi - sensor fusion models, there has been a notable enhancement in the performance of perception tasks within in terms of autonomous driving. despite these advancements, the challenges persist, particularly in the fusion of data from cameras and lidar sensors. a critial concern is the accurate alignment of data from these disparate sensors. our observations indicate that the projected positions of lidar points often misalign on the corresponding image. furthermore, fusion models appear to struggle in accurately segmenting these misaligned points. in this paper, we would like to address this problem carefully, with a specific focus on the nuscenes dataset and the sota of fusion models 2dpass, and providing the possible solutions or potential improvements.
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arxiv:2309.14932
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ongoing risks from climate change have impacted the livelihood of global nomadic communities, and are likely to lead to increased migratory movements in coming years. as a result, mobility considerations are becoming increasingly important in energy systems planning, particularly to achieve energy access in developing countries. advanced plug and play control strategies have been recently developed with such a decentralized framework in mind, more easily allowing for the interconnection of nomadic communities, both to each other and to the main grid. in light of the above, the design and planning strategy of a mobile multi - energy supply system for a nomadic community is investigated in this work. motivated by the scale and dimensionality of the associated uncertainties, impacting all major design and decision variables over the 30 - year planning horizon, deep reinforcement learning ( drl ) is implemented for the design and planning problem tackled. drl based solutions are benchmarked against several rigid baseline design options to compare expected performance under uncertainty. the results on a case study for ger communities in mongolia suggest that mobile nomadic energy systems can be both technically and economically feasible, particularly when considering flexibility, although the degree of spatial dispersion among households is an important limiting factor. key economic, sustainability and resilience indicators such as cost, equivalent emissions and total unmet load are measured, suggesting potential improvements compared to available baselines of up to 25 %, 67 % and 76 %, respectively. finally, the decomposition of values of flexibility and plug and play operation is presented using a variation of real options theory, with important implications for both nomadic communities and policymakers focused on enabling their energy access.
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arxiv:2212.04136
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on portland ' s south waterfront along with the school of medicine. = = = school of nursing = = = the school of nursing at ohsu offers nursing programs at the undergraduate, graduate, and doctoral levels. the graduate nursing program was most recently ranked 7th overall in the nation by the u. s. news & world report and 5th in the gerontology / geriatric specialty. = = ohsu foundation = = the oregon health & science university foundation is a 501 ( c ) ( 3 ) organization that exists to advance ohsu ' s mission through philanthropy. the doernbecher children ' s hospital foundation merged with the ohsu foundation in 2021. = = controversies = = = = = aerial tram = = = in 2001, ohsu purchased property in what is now known as the south waterfront neighborhood with intentions to expand its facilities there. after the purchase, ohsu began developing plans with the portland office of transportation to connect this location to its marquam hill facilities by way of an aerial tram. before construction of the tram began in 2005, the project was criticized by residents in the neighborhoods located directly below the projected tram route who believed its construction would result in an invasion of privacy and lower property values. the group no tram to ohsu argued that ohsu had not sufficiently justified the benefits of the tram, that the tram would not alleviate traffic congestion on marquam hill as ohsu claimed, and that the project inappropriately made use of public right of way for private purposes. during the construction phase, the project came under additional public scrutiny amid rising construction and operation costs. the final cost of its construction was $ 57 million, almost 4 times over its original projected budget. after opening in december 2006, the tram carried its one millionth passenger on october 17, 2007, and its ten millionth rider on january 8, 2014. = = = peta = = = in 2006, the animal rights group peta brought attention to ohsu research involving sheep. the research, which was being conducted in conjunction with oregon state university was designed to understand the biological mechanisms involved in sexual partner preference. = = notable alumni and faculty = = esther choo, emergency physician, president of the academy of women in academic emergency medicine mustafa culha, chemistry professor, and research group founder brian druker, physician, co - developer of gleevec and director of the knight cancer institute john epley, physician, developer of the epley maneuver suzanne fei, computational biologist, bioinformatics & biostatistics core director catherine
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https://en.wikipedia.org/wiki/Oregon_Health_&_Science_University
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the famous goldbach conjecture remains open for nearly three centuries. recently goldbach graphs are introduced to relate the problem with the literature of graph theory. it is shown that the connectedness of the graphs is equivalent to the affirmative answer of the conjecture. some modified version of the graphs, say, near goldbach graphs are shown to be hamiltonian for small number of vertices. in this context, we introduce a class of graphs, namely, prime multiple missing graphs such that near goldbach graphs are finite intersections of these graphs. we study these graphs for primes 3, 5 and in general for any odd prime p. we prove that these graphs are connected with diameter at most 3 and hamiltonian for even ( > 2 ) vertices. next the intersection of prime multiple missing graphs for primes 3 and 5 are studied. we prove that these graphs are connected with diameter at most 4 and they are also hamiltonian for even ( > 2 ) vertices. we observe that the diameters of finite goldbach graphs and near goldbach graphs are bounded by 5 ( up to 10000 vertices ). we believe further study on these graphs with big data analysis will help to understand structures of near goldbach graphs.
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arxiv:2501.02529
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recent discoveries of anomalously bright radar reflections below the mars south polar layered deposit ( spld ) have sparked new speculation that liquid water may be present below the ice cap. the reflections, discovered in data acquired by the mars advanced radar for subsurface and ionospheric sounding ( marsis ) on board the mars express orbiter, were interpreted as reflections from damp materials or even subsurface ponds and lakes similar to those found beneath earth ' s ice sheets. recent studies, however, have questioned the feasibility of melting and maintaining liquid water below the spld. herein, we compare radar simulations to marsis observations in order to present an alternate hypothesis : that the bright reflections are the result of interference between multiple layer boundaries, with no liquid water present. this new interpretation is more consistent with known conditions on modern mars.
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arxiv:2107.03497
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adverse weather conditions, including snow, rain, and fog, pose a major challenge for both human and computer vision. handling these environmental conditions is essential for safe decision making, especially in autonomous vehicles, robotics, and drones. most of today ' s supervised imaging and vision approaches, however, rely on training data collected in the real world that is biased towards good weather conditions, with dense fog, snow, and heavy rain as outliers in these datasets. without training data, let alone paired data, existing autonomous vehicles often limit themselves to good conditions and stop when dense fog or snow is detected. in this work, we tackle the lack of supervised training data by combining synthetic and indirect supervision. we present zeroscatter, a domain transfer method for converting rgb - only captures taken in adverse weather into clear daytime scenes. zeroscatter exploits model - based, temporal, multi - view, multi - modal, and adversarial cues in a joint fashion, allowing us to train on unpaired, biased data. we assess the proposed method on in - the - wild captures, and the proposed method outperforms existing monocular descattering approaches by 2. 8 db psnr on controlled fog chamber measurements.
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arxiv:2102.05847
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we analyze the valley composition of one electron bound to a shallow donor close to a si / barrier interface as a function of an applied electric field. a full six - valley effective mass model hamiltonian is adopted. for low fields, the electron ground state is essentially confined at the donor. at high fields the ground state is such that the electron is drawn to the interface, leaving the donor practically ionized. valley splitting at the interface occurs due to the valley - orbit coupling, v _ vo ^ i = | v _ vo ^ i | e ^ { i theta }. at intermediate electric fields, close to a characteristic shuttling field, the electron states may constitute hybridized states with valley compositions different from the donor and the interface ground states. the full spectrum of energy levels shows crossings and anti - crossings as the field varies. the degree of level repulsion, thus the width of the anti - crossing gap, depends on the relative valley compositions, which vary with | v _ vo ^ i |, theta and the interface - donor distance. we focus on the valley configurations of the states involved in the donor - interface tunneling process, given by the anti - crossing of the three lowest eigenstates. a sequence of two anti - crossings takes place and the complex phase theta affects the symmetries of the eigenstates and level anti - crossing gaps. we discuss the implications of our results on the practical manipulation of donor electrons in si nanostructures.
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arxiv:1203.6245
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we review recent progress in constructing realistic brane models from type i string vacua. explicit models with three families of the standard model gauge group and its left - right generalizations are presented with supersymmetry broken at the string scale of order $ m _ s \ sim 10 ^ { 10 - 12 } $ gev, realizing gravity mediated supersymmetry breaking at low energies. unification of couplings occurs at the string scale due to the particular u ( 1 ) normalizations of d - branes, as well as to the existence of a higgs field per family of quarks and leptons. the proton is naturally stable due to intrinsic discrete symmetries of the corresponding string theory. in particular r - parity appears as a natural stringy symmetry. there are axionic fields with the right couplings as to solve the strong cp problem. similar realizations are also presented for a string scale of 1 tev, although without solving the gauge unification problem. open questions are briefly discussed.
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arxiv:hep-ph/0005033
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we present a model calculation of transverse - momentum - dependent distributions ( tmds ) of gluons in the nucleon. the model is based on the assumption that a nucleon can emit a gluon, and what remains after the emission is treated as a single spectator particle. this spectator particle is considered to be on - shell, but its mass is allowed to take a continuous range of values, described by a spectral function. the nucleon - gluon - spectator coupling is described by an effective vertex containing two form factors. we fix the model parameters to obtain the best agreement with collinear gluon distributions extracted from global fits. we study the tomography in momentum space of gluons inside nucleons for various combinations of their polarizations. these can be used to make predictions of observables relevant for gluon tmd studies at current and future collider facilities.
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arxiv:2005.02288
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we study a many - body system of interacting fermionic atoms of two species that are in thermodynamic equilibrium with their condensed heteronuclear bound states ( molecules ). in order to describe such an equilibrium state, we use a microscopic approach that involves the bogoliubov model for a weakly interacting bose gas and approximate formulation of the second quantization method in the presence of bound states of particles elaborated earlier by the authors. this microscopic approach is valid at low temperatures, when the average kinetic energy of all the components in the system is small in comparison with the bound state energy. the coupled equations, which relate the chemical potentials of fermionic components and molecular condensate density, are obtained within the proposed theory. at zero temperature, these equations are analyzed both analytically and numerically, attracting the relevant experimental data. we find the conditions at which a condensate of heteronuclear molecules coexists in equilibrium with degenerate components of a fermi gas. the ground state energy and single - particle excitation spectrum are found. the boundaries of the applicability of the developed microscopic approach are analyzed.
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arxiv:1501.01177
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lenstra introduced the notion of a euclidean ideal class, which is a generalization of the euclidean domain. lenstra also proved that the euclidean ideal in a number field $ k $ implies that the class group of $ k $ is cyclic. we construct a family of biquadratic fields with a euclidean ideal whenever the class number is 2. this extends the families given by graves, hsu, chattopadhyay, and muthukrishnan.
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arxiv:2009.06464
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we report on a numerical reinvestigation of the aoki phase in full lattice qcd with two flavors of unimproved wilson fermions. for zero temperature the aoki phase can be confirmed at inverse coupling $ \ beta = 4. 0 $ and $ \ beta = 4. 3 $, but not at $ \ beta = 4. 6 $ and $ \ beta = 5. 0 $. at non - zero temperature the aoki phase was found to exist also at $ \ beta = 4. 6 $.
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arxiv:hep-lat/0309059
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the recently discovered van der waals magnetic semiconductor cri2 shows promise for spintronic applications. its electronic and magnetic properties are known to be strongly influenced by electronic correlations. in this work, we employ density functional theory calculations where electronic correlations in cri2 are considered within an on - site coulomb interaction, u, with u being determined using the perturbative approach based on the linear response method. we show that the accuracy of an on - site coulomb interaction is essential for predicting the non - centrosymmetric orthorhombic ground state of cri2, which allows the existence of ferroelectricity and non - zero dzyaloshinskii - moriya ( dmi ) interaction. our calculation shows that the ground state of bulk cri2 has electric polarization of 0. 15 { \ mu } c / cm - 2 pointing along the z - axis and the small dmi energy that changes sign with the ferroelectric polarization switching. the dmi and polarization are enhanced to 0. 28 mev / formula - unit and 0. 63 { \ mu } c / cm - 2 when pt intercalates bilayers of cri2, due to its large spin - orbit coupling strength and large off - center displacement. such an enhanced dmi leads to the n \ ' eel skyrmions, whose handedness is controlled by ferroelectric polarization. our work contributes to the creation and manipulation of bits in skyrmions - based memory devices.
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arxiv:2408.01568
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the concept of software defined wide area network ( sd - wan or sdwan ) is central to modern computer networking, particularly in enterprise networks. by definition, these systems form network perimeter and connect internet, wan, extranet, and branches that makes them crucial from cybersecurity point of view. the goal of this paper is to provide the results of passive and active fingerprinting for sd - wan systems using a common threat intelligence approach. we explore internet - based and cloud - based publicly available sd - wan systems using well - known shodan and censys search engines and custom developed automation tools and show that most of the sd - wan systems have known vulnerabilities related to outdated software and insecure configuration.
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arxiv:1808.09027
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we discuss the possibility that r - process nucleosynthesis may occur in the winds from gamma ray burst accretion disks. this can happen if the temperature of the disk is sufficiently high that electron antineutrinos are trapped as well as neutrinos. this implies accretion disks with greater than a solar mass per second accretion rate, although lower accretion rates with higher black hole spin parameters may provide viable environments as well. additionally, the outflow from the disk must either have relatively low entropy, e. g. around s = 10, or the initial acceleration of the wind must be slow enough that it is neutrino and antineutrino capture as opposed to electron and positron capture that sets the electron fraction.
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arxiv:astro-ph/0407555
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recent besiii data indicate a significant rate of the process $ e ^ + e ^ - \ to h _ c \ pi ^ + \ pi ^ - $ at the y ( 4260 ) and y ( 4360 ) resonances, implying a substantial breaking of the heavy quark spin symmetry. we consider these resonances within the picture of hadrocharmonium, i. e. of ( relatively ) compact charmonium embedded in a light quark mesonic excitation. we suggest that the resonances y ( 4260 ) and y ( 4360 ) are a mixture, with mixing close to maximal, of two states of hadrochamonium, one containing a spin - triplet $ c \ bar c $ pair and the other containing a spin - singlet heavy quark pair. we argue that this model is in a reasonable agreement with the available data and produces distinctive and verifiable predictions for the energy dependence of the production rate in $ e ^ + e ^ - $ annihilation of the final states $ j / \ psi \ pi \ pi $, $ \ psi ' \ pi \ pi $ and $ h _ c \ pi \ pi $, including the pattern of interference between the two resonances.
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arxiv:1309.1681
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we prove a known 2 - coloring of the integers $ [ n ] : = \ { 1, 2, 3, \ ldots, n \ } $ minimizes the number of monochromatic arithmetic 3 - progressions under certain restrictions. a monochromatic arithmetic progression is a set of equally - spaced integers that are all the same color. previous work by parrilo, robertson and saracino conjectured an optimal coloring for large $ n $ that involves 12 colored blocks. here, we prove that the conjecture is optimal among anti - symmetric colorings with 12 or fewer colored blocks. we leverage a connection to the coloring of the continuous interval $ [ 0, 1 ] $ used by parrilo, robertson, and saracino as well as by butler, costello and graham. our proof identifies classes of colorings with permutations, then counts the permutations using mixed integer linear programming.
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arxiv:2301.00336
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" how much c. e. sets could cover a given set? " in this paper we are going to answer this question. also, in this approach some old concepts come into a new arrangement. the major goal of this article is to introduce an appropriate definition for this purpose. introduction in computability theory ( recursion theory ) in the first step we wish to recognize the sets which could be enumerated by turing machines ( equivalently, algorithms ) and in the next step we will compare these sets by some reasonable order ( like turing degree ). also sometimes with some extra information ( oracles ) a class of non c. e. sets show the same behavior as c. e. sets ( post hierarchy and related theorems ). here we try another approach : " let a be an arbitrary set and we wish to recognize how much this set might be covered by a c. e. set? " although in some sense this approach could be seen in some definitions of recursion theory, but at the best of our knowledge it didn ' t considered as an approach yet, even though it is able to shed a light on some subjects of computability of sets. defining this approach is not quite straightforward and there are some obstacles to define them. to overcome these difficulties we modify the definitions. we have an alternative problem here when we consider recursive sets and not c. e. sets. in this case, the problem would be : " let a be an arbitrary set and we wish to know that how much this set might be covered by a recursive set? " here, we try the first definition and the first problem.
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arxiv:1203.0841
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probabilistic programming languages ( ppls ) allow programmers to construct statistical models and then simulate data or perform inference over them. many ppls restrict models to a particular instance of simulation or inference, limiting their reusability. in other ppls, models are not readily composable. using haskell as the host language, we present an embedded domain specific language based on algebraic effects, where probabilistic models are modular, first - class, and reusable for both simulation and inference. we also demonstrate how simulation and inference can be expressed naturally as composable program transformations using algebraic effect handlers.
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arxiv:2203.04608
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we present the results from two - point spatial correlation analyses on x - ray confirmed northern abell clusters. the cluster samples are subsets of a volume - limited rosat all - sky survey study of 294 abell clusters of which 240 are x - ray luminous. we examined magnitude - and volume - complete samples for differences according to richness and x - ray luminosity. for r > = 1 clusters, we find r _ 0 = 22h ^ - 1mpc and gamma = - 1. 7, which is consistent with previous analyses of visually selected clusters. we also find no indications of line - of - sight anisotropies. for r > = 0 clusters, we find r _ 0 = 17. 5h ^ - 1mpc which is considerably lower than recent determinations of r _ 0 for similar x - ray bright cluster samples ( e. g. the xbacs and the rass1 clusters ). all of the r > = 0 x - ray confirmed samples, including the xbacs and rass1 clusters, show line - of - sight anisotropies. since x - ray emissions confirm a cluster ' s reality, we conclude that these anisotropies are not the result of spuriously selected clusters. we also examine the abell clusters for the depedence of r _ 0 and gamma on x - ray luminosity, and find no evidence for r _ 0 to grow with increasing x - ray luminosity thresholds. this is contrary to similar l _ x vs. r _ 0 analyses of the rass1 and xbacs cluster samples. we describe selection effects within the flux - limited xbacs and rass1 samples and suggest how they can affect both the size of r _ 0 and its dependence on l _ x.
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arxiv:astro-ph/9906423
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