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the availability heuristic is a strategy that people use to make quick decisions but often lead to systematic errors. we propose three ways that visualization could facilitate unbiased decision - making. first, visualizations can alter the way our memory stores the events for later recall, so as to improve users ' long - term intuitions. second, the known biases could lead to new visualization guidelines. third, we suggest the design of decision - making tools that are inspired by heuristics, e. g. suggesting intuitive approximations, rather than target to present exhaustive comparisons of all possible outcomes, or automated solutions for choosing decisions.
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arxiv:1610.02857
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we consider expected utility maximisation problem for exponential levy models and hara utilities in presence of illiquid asset in portfolio. this illiquid asset is modelled by an option of european type on another risky asset which is correlated with the first one. under some hypothesis on levy processes, we give the expressions of information processes figured in maximum utility formula. as applications, we consider black - scholes models with correlated brownian motions, and also black - scholes models with jump part represented by poisson process.
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arxiv:1509.02727
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matching information across image and text modalities is a fundamental challenge for many applications that involve both vision and natural language processing. the objective is to find efficient similarity metrics to compare the similarity between visual and textual information. existing approaches mainly match the local visual objects and the sentence words in a shared space with attention mechanisms. the matching performance is still limited because the similarity computation is based on simple comparisons of the matching features, ignoring the characteristics of their distribution in the data. in this paper, we address this limitation with an efficient learning objective that considers the discriminative feature distributions between the visual objects and sentence words. specifically, we propose a novel adversarial discriminative domain regularization ( addr ) learning framework, beyond the paradigm metric learning objective, to construct a set of discriminative data domains within each image - text pairs. our approach can generally improve the learning efficiency and the performance of existing metrics learning frameworks by regulating the distribution of the hidden space between the matching pairs. the experimental results show that this new approach significantly improves the overall performance of several popular cross - modal matching techniques ( scan, vsrn, bfan ) on the ms - coco and flickr30k benchmarks.
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arxiv:2010.12126
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we derive and analyze a broad class of finite element methods for numerically simulating the stationary, low reynolds number flow of concentrated mixtures of several distinct chemical species in a common thermodynamic phase. the underlying partial differential equations that we discretize are the stokes $ \ unicode { x2013 } $ onsager $ \ unicode { x2013 } $ stefan $ \ unicode { x2013 } $ maxwell ( sosm ) equations, which model bulk momentum transport and multicomponent diffusion within ideal and non - ideal mixtures. unlike previous approaches, the methods are straightforward to implement in two and three spatial dimensions, and allow for high - order finite element spaces to be employed. the key idea in deriving the discretization is to suitably reformulate the sosm equations in terms of the species mass fluxes and chemical potentials, and discretize these unknown fields using stable $ h ( \ textrm { div } ) \ unicode { x2013 } l ^ 2 $ finite element pairs. we prove that the methods are convergent and yield a symmetric linear system for a picard linearization of the sosm equations, which staggers the updates for concentrations and chemical potentials. we also discuss how the proposed approach can be extended to the newton linearization of the sosm equations, which requires the simultaneous solution of mole fractions, chemical potentials, and other variables. our theoretical results are supported by numerical experiments and we present an example of a physical application involving the microfluidic non - ideal mixing of hydrocarbons.
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arxiv:2408.17390
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we analyze the impact of the recently released cdf - ii measurement of $ w $ mass on the smeft analyses of the electroweak precision data as well as higgs and electroweak diboson productions. we work in the hagiwara, ishihara, szalapski, and zeppenfeld basis in which eight generation - independent operators enter in the electroweak precision data at tree level and, unlike in the warsaw basis, the analysis of that set of data constrains all the eight wilson coefficients, without the need of combination with higgs or electroweak diboson data results. we show that in the global analysis the determination of the coefficients of all operators which do not enter the electroweak precision data are barely affected by the new $ m _ w $ determination.
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arxiv:2204.10130
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quantum lambda calculus has been studied mainly as an idealized programming language - - the evaluation essentially corresponds to a deterministic abstract machine. very little work has been done to develop a rewriting theory for quantum lambda calculus. recent advances in the theory of probabilistic rewriting give us a way to tackle this task with tools unavailable a decade ago. our primary focus is standardization and normalization results.
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arxiv:2411.14856
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let m be a closed, oriented, n - dimensional manifold. in this paper we give a morse theoretic description of the string topology operations introduced by chas and sullivan, and extended by the first author, jones, godin, and others. we do this by studying maps from surfaces with cylindrical ends to m, such that on the cylinders, they satisfy the gradient flow equation of a morse function on the loop space, lm. we then give morse theoretic descriptions of related constructions, such as the thom and euler classes of a vector bundle, as well as the shriek, or unkehr homomorphism.
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arxiv:0809.0868
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the notion of an automaton over a changing alphabet $ x = ( x _ i ) _ { i \ geq 1 } $ is used to define and study automorphism groups of the tree $ x ^ * $ of finite words over $ x $. the concept of bi - reversibility for mealy - type automata is extended to automata over a changing alphabet. it is proved that a non - abelian free group can be generated by a two - state bi - reversible automaton over a changing alphabet $ x = ( x _ i ) _ { i \ geq 1 } $ if and only if $ x $ is unbounded. the characterization of groups generated by a two - state bi - reversible automaton over the sequence of binary alphabets is established.
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arxiv:1702.00435
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the jsns2 - ii ( the second phase of jsns2, j - parc sterile neutrino search at j - parc spallation neutron source ) is an experiment aimed at searching for sterile neutrinos. this experiment has entered its second phase, employing two liquid scintillator detectors located at near and far positions from the neutrino source. recently, the far detector of the experiment has been completed and is currently in the calibration phase. this paper presents a detailed description of the calibration process utilizing the led system. the led system of the far detector uses two ultra - violet ( uv ) leds, which are effective in calibrating all of pmts at once. the uv light is converted into the visible light wavelengths inside liquid scintillator via the wavelength shifters, providing pseudo - isotropic light. the properties of all functioning photo - multiplier - tubes ( pmts ) to detect the neutrino events in the far detector, such as gain, its dependence of supplied high voltage ( hv ), and peak - to - valley ( pv ) were calibrated. to achieve a good energy resolution for physics events, up to 10 % of the relative gain adjustment is required for all functioning pmts. this will be achieved using the measured hv curves and the led calibration. the peak - to - valley ( pv ) ratio values are the similar to those from the production company, which distinguish the single photo - electron signal from the pedestal. additionally, the precision of pmt signal timing is measured to be 2. 1 ns, meeting the event reconstruction requirement of 10 ns.
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arxiv:2503.09031
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a successful defensive strategy in ice hockey games is often designed empirically by an experienced professional. the majority of previous work on automating the strategy focuses on analyzing spatial data to decide the most optimal formation and action but cannot generalize the system to real games with real - time capabilities. we propose a novel control logic for generating real - time ice hockey defensive motion based on a control barrier function ( cbf ) and coverage control to extend our antecessors ' logic that succeeds in duplicating ideal formations for specific scenes. to this end, we first present an ellipsoidal cbf to overcome the drawbacks of the existing line - based cbf of our antecessors. we also tune and add a novel density function to reflect real specifications more precisely than the previous work. the control logic is then demonstrated through simulations with offensive motion in real games. it is confirmed that the present logic generates valid defensive movements without specification to these specific scenes. we further exemplify that the logic generates proper motion under ice hockey ' s man - to - man and zone defense strategies and their intermediate strategies by tuning the logic. this would contribute to reducing the efforts of the practitioners to educate ice hockey players.
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arxiv:2111.10804
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in has been recently shown [ 1 ] that in dirac ' s hole theory the vacuum state is not the minimum energy state but that there exist quantum states with less energy than that of the vacuum state. in this paper we extend this discussion to quantum field theory ( qft ) and consider the question of whether or not the vacuum in qft is the state of minimum energy. it will be shown that for a " simple " field theory, consisting of a quantized fermion field interacting with a classical electric field in 1 - 1d space - time, there exist quauntum states with less energy than that of the vacuum state.
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arxiv:quant-ph/0701022
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we prove a stability estimate of logarithmic type for the inverse problem consisting in the determination of the surface impedance of an obstacle from the scattering amplitude. we present a simple and direct proof which is essentially based on an elliptic carleman inequality.
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arxiv:1201.2552
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pure electronic raman spectra with no phonon structures superimposed to the electronic continuum, are reported for the first time, in optimally doped $ hgba _ { 2 } cacu _ { 2 } o _ { 6 + \ delta } $ single crystals $ ( t _ { c } = 126 $ k ). our low temperature spectra ( 15 k ) for the $ a _ { 1g } $, $ b _ { 1g } $ and $ b _ { 2g } $ symmetries exhibit striking differences with previous data in $ bi _ { 2 } sr _ { 2 } cacu _ { 2 } o _ { 8 + \ delta }. $ the shape of the spectra for the various symmetries cannot be fitted by devereaux ' s $ d _ { x ^ { 2 } - y ^ { 2 } } $ calculations, but strongly suggests a $ d _ { x y } $ gap, with its minima in the [ 100 ] and [ 010 ] directions.
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arxiv:cond-mat/9609121
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we investigate the mixed - valent regime of a two - configuration anderson impurity model for uranium ions, with separate quadrupolar and magnetic doublets. with a new monte carlo approach and the non - crossing approximation we find : ( i ) a non - fermi - liquid fixed point with two - channel kondo model critical behavior ; ( ii ) distinct energy scales for screening the low - lying and excited doublets ; ( iii ) a semi - quantitative explanation of magnetic - susceptibility data for u $ _ { 1 - x } $ th $ _ x $ be $ _ { 13 } $ assuming 60 - 70 % quadrupolar doublet ground - state weight, supporting the quadrupolar - kondo interpretation.
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arxiv:cond-mat/9807303
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the ( 1 + 1 ) - dimensional nonlinear boundary value problem, modeling the process of melting and evaporation of metals, is studied by means of the classical lie symmetry method. all possible lie operators of the nonlinear heat equation, which allow us to reduce the problem to the boundary value problem for the system of ordinary differential equations, are found. the forms of heat conductivity coefficients are established when the given problem can be analytically solved in an explicit form.
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arxiv:1211.6908
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proteinoids are thermal proteins which form microspheres in water in presence of salt. ensembles of proteinoid microspheres exhibit passive non - linear electrical properties and active neuron - like spiking of electrical potential. we propose that various neuromorphic computing architectures can be prototyped from the proteinoid microspheres. a key feature of a neuromorphic system is a learning. through the use of optical and resistance measurements, we study mechanisms of learning in ensembles of proteinoid microspheres. we anlyse 16 types of proteinoids, study their intrinsic morphology and electrical properties. we demonstrate that proteinoids can learn, memorize, and habituate, making them a promising candidate for novel computing.
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arxiv:2306.14362
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to enhance the robustness of cooperative driving to cyberattacks, we study a controller - oriented approach to mitigate the effect of a class of false - data injection ( fdi ) attacks. by reformulating a given dynamic cooperative adaptive cruise control scheme ( the base controller ), we show that a class of new but equivalent controllers ( base controller realizations ) can represent the base controller. this controller class exhibits the same platooning behavior in the absence of attacks, but in the presence of attacks, their robustness varies with the realization. we propose a prescriptive synthesis framework where the base controller and the system dynamics are written in new coordinates via an invertible coordinate transformation on the controller state. because the input - output behavior is invariant under coordinate transformations, the input - output behavior is unaffected ( so controller realizations do not change the system ' s closed - loop performance ). however, each controller realization may require a different combination of sensors. subsequently, we obtain the optimal combination of sensors that minimizes the effect of fdi attacks by solving a linear matrix inequality while quantifying the fdi ' s attack impact through reachability analysis. through simulation studies, we demonstrate that this approach enhances the robustness of cooperative driving without relying on a detection scheme and maintaining all system properties.
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arxiv:2404.05361
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we introduce the concept of $ t $ - spread monomials and $ t $ - spread strongly stable ideals. these concepts are a natural generalization of strongly stable and squarefree strongly stable ideals. for the study of this class of ideals we use the $ t $ - fold stretching operator. it is shown that $ t $ - spread strongly stable ideals are componentwise linear. their height, their graded betti numbers and their generic initial ideal are determined. we also consider the toric rings whose generators come from $ t $ - spread principal borel ideals.
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arxiv:1805.02368
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safety requirements in dynamical systems are commonly enforced with set invariance constraints over a safe region of the state space. control barrier functions, which are lyapunov - like functions for guaranteeing set invariance, are an effective tool to enforce such constraints and guarantee safety when the system is represented as a point in the state space. in this paper, we introduce extent - compatible control barrier functions as a tool to enforce safety for the system including its volume ( extent ) in the physical world. in order to implement the extent - compatible control barrier functions framework, a sum - of - squares based optimization program is proposed. since sum - of - squares programs can be computationally prohibitive, we additionally introduce a sampling based method in order to retain the computational advantage of a traditional barrier function based quadratic program controller. we prove that the proposed sampling based controller retains the guarantee for safety. simulation and robotic implementation results are also provided.
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arxiv:2001.07210
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asymptotic net is an important concept in discrete differential geometry. in this paper, we show that we can associate affine discrete geometric concepts to an arbitrary non - degenerate asymptotic net. these concepts include discrete affine area, mean curvature, normal and co - normal vector fields and cubic form, and they are related by structural and compatibility equations. we consider also the particular cases of affine minimal surfaces and affine spheres.
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arxiv:0805.2060
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we conduct a systematic numerical study of passive scalar structures in supersonic turbulent flows. we find that the degree of intermittency in the scalar structures increases only slightly as the flow changes from transonic to highly supersonic, while the velocity structures become significantly more intermittent. this difference is due to the absence of shock - like discontinuities in the scalar field. the structure functions of the scalar field are well described by the intermittency model of she and l \ ' { e } v \ ^ { e } que [ phys. rev. lett. 72, 336 ( 1994 ) ], and the most intense scalar structures are found to be sheet - like at all mach numbers.
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arxiv:1103.5489
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scalar fields coupled to dark matter by conformal or disformal transformations give rise to a general class of scalar - tensor theories which leads to a rich phenomenology in a cosmological setting. while this possibility has been studied comprehensively in the literature for scalar fields, the vector case has been hardly treated. we build hence models based on vector fields conformally and disformally coupled to dark matter and derive explicitly the general covariant form of the interaction term in an independent way of the gravity theory, whereby this result can be applied to general vector - tensor theories. for concreteness, the standard proca theory with a vector exponential potential is taken to describe the vector - tensor sector, and some specific coupling functions are assumed to study the cosmological background dynamics by dynamical system techniques. despite of choosing such a minimalist form for the underlying theory, the parameter space is considerably enriched compared to the uncoupled case due to the novel interactions, leading to new branches of solutions for the vector equation of motion. thus, different trajectories can exist in phase space depending on the coupling parameters associated to the conformal and disformal functions. from here, new emerging vector - dark matter scaling solutions, and renewed stable attractor points are found to drive the late - time accelerated expansion of the universe. as a first examination about instabilities issues, we derive general conditions to avoid classical instabilities in a more general setup of the theory. numerical calculations are performed as well to investigate more quantitatively the impact of the conformal and disformal couplings on the cosmological background evolution. these effects depend essentially on the strength on the coupling parameters and, in some specific cases, on their associated signs.
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arxiv:2202.07027
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we present aroma ( attentive reduced order model with attention ), a framework designed to enhance the modeling of partial differential equations ( pdes ) using local neural fields. our flexible encoder - decoder architecture can obtain smooth latent representations of spatial physical fields from a variety of data types, including irregular - grid inputs and point clouds. this versatility eliminates the need for patching and allows efficient processing of diverse geometries. the sequential nature of our latent representation can be interpreted spatially and permits the use of a conditional transformer for modeling the temporal dynamics of pdes. by employing a diffusion - based formulation, we achieve greater stability and enable longer rollouts compared to conventional mse training. aroma ' s superior performance in simulating 1d and 2d equations underscores the efficacy of our approach in capturing complex dynamical behaviors.
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arxiv:2406.02176
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we provide a counterexample to show that the generic form of entropy s ( p ) = sum _ i g ( p _ i ) is not always stable against small variation of probability distribution ( lesche stability ) even if is concave function on [ 0, 1 ] and analytic on ] 0, 1 ]. our conclusion is that the stability of such a generic functional needs more hypotheses on the property of the function g, or in other words, the stability of entropy cannot be discussed at this formal stage.
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arxiv:0903.4169
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we report measurements for two - body charmless b decays with an eta ' meson in the final state. using 11. 1x10 ^ 6 bbbar pairs collected with the belle detector, we find bf ( b ^ + - > eta ' k ^ + ) = ( 79 ^ + 12 _ - 11 + - 9 ) x10 ^ - 6 and bf ( b ^ 0 - > eta ' k ^ 0 ) = ( 55 ^ + 19 _ - 16 + - 8 ) x10 ^ - 6, where the first and second errors are statistical and systematic, respectively. no signal is observed in the mode b ^ + - > eta ' pi ^ +, and we set a 90 % confidence level upper limit of bf ( b ^ + - > eta ' pi ^ + ) < 7x10 ^ - 6. the cp asymmetry in b ^ + - - > eta ' k ^ + - decays is investigated and a limit at 90 % confidence level of - 0. 20 < acp < 0. 32 is obtained.
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arxiv:hep-ex/0108010
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cloaking using complementary media was suggested by lai et al. in [ 8 ]. the study of this problem faces two difficulties. firstly, this problem is unstable since the equations describing the phenomenon have sign changing coefficients, hence the ellipticity is lost. secondly, the localized resonance, i. e., the field explodes in some regions and remains bounded in some others, might appear. in this paper, we give a proof of cloaking using complementary media for a class of schemes inspired from [ 8 ] in the quasistatic regime. to handle the localized resonance, we introduce the technique of removing localized singularity and apply a three spheres inequality. the proof also uses the reflecting technique in [ 11 ]. to our knowledge, this work presents the first proof on cloaking using complementary media.
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arxiv:1310.5483
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we evaluate the exact $ qed _ { 2 + 1 } $ effective action for fermions in the presence of a family of static but spatially inhomogeneous magnetic field profiles. this exact result yields an all - orders derivative expansion of the effective action, and indicates that the derivative expansion is an asymptotic, rather than a convergent, expansion.
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arxiv:hep-th/9611019
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networks capture pairwise interactions between entities and are frequently used in applications such as social networks, food networks, and protein interaction networks, to name a few. communities, cohesive groups of nodes, often form in these applications, and identifying them gives insight into the overall organization of the network. one common quality function used to identify community structure is modularity. in hu et al. [ siam j. app. math., 73 ( 6 ), 2013 ], it was shown that modularity optimization is equivalent to minimizing a particular nonconvex total variation ( tv ) based functional over a discrete domain. they solve this problem, assuming the number of communities is known, using a merriman, bence, osher ( mbo ) scheme. we show that modularity optimization is equivalent to minimizing a convex tv - based functional over a discrete domain, again, assuming the number of communities is known. furthermore, we show that modularity has no convex relaxation satisfying certain natural conditions. we therefore, find a manageable non - convex approximation using a ginzburg landau functional, which provably converges to the correct energy in the limit of a certain parameter. we then derive an mbo algorithm with fewer hand - tuned parameters than in hu et al. and which is 7 times faster at solving the associated diffusion equation due to the fact that the underlying discretization is unconditionally stable. our numerical tests include a hyperspectral video whose associated graph has 2. 9x10 ^ 7 edges, which is roughly 37 times larger than was handled in the paper of hu et al.
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arxiv:1707.09285
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this chapter will primarily focus on the studies of quantum optics with semiconductor, epitaxially grown quantum dots embedded in photonic crystal cavities. we will start by giving brief introductions into photonic crystals and quantum dots, then proceed with the introduction to cavity quantum electrodynamics ( qed ) effects, with a particular emphasis on the demonstration of these effects on the quantum dot - photonic crystal platform. finally, we will focus on the applications of such cavity qed effects.
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arxiv:1402.2541
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the pseudo - newtonian potential of paczynski and wiita for particles orbiting a schwarzschild black hole is generalized to arbitrary static and spherically symmetric spacetimes, including black hole solutions of alternative theories of gravity. in addition to being more general, our prescription differs substantially from a previous one in the literature, showing that even the association of a pseudo - newtonian potential with a simple black hole metric is not unique.
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arxiv:1511.00699
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negative dependence in tournaments has received attention in the literature. the property of negative orthant dependence ( nod ) was proved for different tournament models with a special proof for each model. for general round - robin tournaments and knockout tournaments with random draws, malinovsky and rinott ( 2023 ) unified and simplified many existing results in the literature by proving a stronger property, negative association ( na ). for a knockout tournament with a non - random draw, malinovsky and rinott ( 2023 ) presented an example to illustrate that s is nod but not na. however, their proof is not correct. in this paper, we establish the properties of negative regression dependence ( nrd ), negative left - tail dependence ( nltd ) and negative right - tail dependence ( nrtd ) for a knockout tournament with a random draw and with players being of equal strength. for a knockout tournament with a non - random draw and with equal strength, we prove that s is na and nrtd, while s is, in general, not nrd or nltd.
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arxiv:2505.01971
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backpropagation - based visualizations have been proposed to interpret convolutional neural networks ( cnns ), however a theory is missing to justify their behaviors : guided backpropagation ( gbp ) and deconvolutional network ( deconvnet ) generate more human - interpretable but less class - sensitive visualizations than saliency map. motivated by this, we develop a theoretical explanation revealing that gbp and deconvnet are essentially doing ( partial ) image recovery which is unrelated to the network decisions. specifically, our analysis shows that the backward relu introduced by gbp and deconvnet, and the local connections in cnns are the two main causes of compelling visualizations. extensive experiments are provided that support the theoretical analysis.
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arxiv:1805.07039
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measuring the predictability and complexity of time series using entropy is essential tool de - signing and controlling a nonlinear system. however, the existing methods have some drawbacks related to the strong dependence of entropy on the parameters of the methods. to overcome these difficulties, this study proposes a new method for estimating the entropy of a time series using the lognnet neural network model. the lognnet reservoir matrix is filled with time series elements according to our algorithm. the accuracy of the classification of images from the mnist - 10 database is considered as the entropy measure and denoted by nneten. the novelty of entropy calculation is that the time series is involved in mixing the input information in the res - ervoir. greater complexity in the time series leads to a higher classification accuracy and higher nneten values. we introduce a new time series characteristic called time series learning inertia that determines the learning rate of the neural network. the robustness and efficiency of the method is verified on chaotic, periodic, random, binary, and constant time series. the comparison of nneten with other methods of entropy estimation demonstrates that our method is more robust and accurate and can be widely used in practice.
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arxiv:2107.08399
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one of the key objectives in investigating small stochastic systems is the development of micrometer - sized engines and the understanding of their thermodynamics. however, the primary mathematical tool used for this purpose, the overdamped approximation, has a critical limitation : it fails to fully capture the thermodynamics when the temperature varies over time, as the velocity is not considered in the approximation. specifically, we show that heat dissipation and entropy production calculated under the overdamped approximation deviate from their true values. these discrepancies are termed thermodynamic anomalies. to overcome this limitation, we analytically derive expressions for these anomalies in the presence of a general time - varying temperature. one notable feature of the result is that high viscosity and small mass, though both leading to the same overdamped dynamic equations, result in different thermodynamic anomaly relations. our results have significant implications, particularly for accurately calculating the efficiency of heat engines operating in overdamped environments with time - varying temperatures, without requiring velocity measurements. additionally, our findings offer a simple method for estimating the kinetic energy of an overdamped system.
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arxiv:2503.22367
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an undergraduate degree of slightly longer duration than the bachelor of engineering rather than a standalone postgraduate degree. = = professional practice = = in most countries, a bachelor ' s degree in engineering represents the first step towards professional certification and the degree program itself is certified by a professional body. after completing a certified degree program the engineer must satisfy a range of requirements ( including work experience requirements ) before being certified. once certified the engineer is designated the title of professional engineer ( in the united states, canada and south africa ), chartered engineer or incorporated engineer ( in india, pakistan, the united kingdom, ireland and zimbabwe ), chartered professional engineer ( in australia and new zealand ) or european engineer ( in much of the european union ). the advantages of licensure vary depending upon location. for example, in the united states and canada " only a licensed engineer may seal engineering work for public and private clients ". this requirement is enforced by state and provincial legislation such as quebec ' s engineers act. in other countries, no such legislation exists. practically all certifying bodies maintain a code of ethics that they expect all members to abide by or risk expulsion. in this way these organizations play an important role in maintaining ethical standards for the profession. even in jurisdictions where certification has little or no legal bearing on work, engineers are subject to contract law. in cases where an engineer ' s work fails he or she may be subject to the tort of negligence and, in extreme cases, the charge of criminal negligence. an engineer ' s work must also comply with numerous other rules and regulations, such as building codes and legislation pertaining to environmental law. professional bodies of note for electrical engineers include the institute of electrical and electronics engineers ( ieee ) and the institution of engineering and technology ( iet ). the ieee claims to produce 30 % of the world ' s literature in electrical engineering, has over 360, 000 members worldwide and holds over 3, 000 conferences annually. the iet publishes 21 journals, has a worldwide membership of over 150, 000, and claims to be the largest professional engineering society in europe. obsolescence of technical skills is a serious concern for electrical engineers. membership and participation in technical societies, regular reviews of periodicals in the field and a habit of continued learning are therefore essential to maintaining proficiency. an miet ( member of the institution of engineering and technology ) is recognised in europe as an electrical and computer ( technology ) engineer. in australia, canada, and the united states, electrical engineers make up around 0. 25 % of the labor force. =
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https://en.wikipedia.org/wiki/Electrical_engineering
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organic matter. = = = examples = = = energy saving modules heat pump hydrogen fuel cell hydroelectricity ocean thermal energy conversion photovoltaic solar power wave energy wind power wind turbine = = = = renewable energy innovations = = = = the intersection of technology and sustainability has led to innovative solutions aimed at enhancing the efficiency of renewable energy systems. one such innovation is the integration of wind and solar power to maximize energy production. companies like uneole are pioneering technologies that combine solar panels with wind turbines on the same platform, which is particularly advantageous for urban environments with limited space. this hybrid system not only conserves space but also increases the energy yield by leveraging the complementary nature of solar and wind energy availability. furthermore, advancements in offshore wind technology have significantly increased the viability and efficiency of wind energy. modern offshore wind turbines feature improvements in structural design and aerodynamics, which enhance their energy capture and reduce costs. these turbines are now more adaptable to various marine environments, allowing for greater flexibility in location and potentially reducing visual pollution. the floating wind turbines, for example, use tension leg platforms and spar buoys that can be deployed in deeper waters, significantly expanding the potential areas for wind energy generation such innovations not only advance the capabilities of individual renewable technologies but also contribute to a more resilient and sustainable energy grid. by optimizing the integration and efficiency of renewable resources, these technologies play a crucial role in the transition towards a sustainable energy future. = = = energy conservation = = = energy conservation is the utilization of devices that require smaller amounts of energy in order to reduce the consumption of electricity. reducing the use of electricity causes less fossil fuels to be burned to provide that electricity. and it refers to the practice of using less energy through changes in individual behaviors and habits. the main emphasis for energy conservation is the prevention of wasteful use of energy in the environment, to enhance its availability. some of the main approaches to energy conservation involve refraining from using devices that consume more energy, where possible. = = = egain forecasting = = = egain forecasting is a method using forecasting technology to predict the future weather ' s impact on a building. by adjusting the heat based on the weather forecast, the system eliminates redundant use of heat, thus reducing the energy consumption and the emission of greenhouse gases. it is a technology introduced by the egain international, a swedish company that intelligently balances building power consumption. the technology involves forecasting the amount of heating energy required by a building within a specific
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https://en.wikipedia.org/wiki/Environmental_technology
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we present results of high resolution ( ~ 55000 ) spectral observations of 830 photometrically pre - selected candidate red giants in the magnitude range of v = 9 - 12. we develop a pipeline for automated determination of the stellar atmospheric parameters from these spectra and estimate t _ eff, logg, [ fe / h ], microturbulence velocity, and projected rotational velocities, vsini, for the stars. the analysis confirms that the candidate selection procedure yielded red giants with very high success rate. we show that most of these stars are g and k giants with slightly subsolar metallicity ( [ fe / h ] ~ - 0. 3 dex ) an analysis of mg abundances in the sample results in consistency of the [ mg / fe ] vs [ fe / h ] trend with published results.
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arxiv:1011.0744
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in this paper, we deal with non - baire rare sets in category bases which forms $ \ aleph _ 0 $ - independent family, where a rare set is a common generalization of both luzin and sierpinski set.
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arxiv:2409.01430
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nonlinear instability and refraction by ocean currents are both important mechanisms that go beyond the rayleigh approximation and may be responsible for the formation of freak waves. in this paper, we quantitatively study nonlinear effects on the evolution of surface gravity waves on the ocean, to explore systematically the effects of various input parameters on the probability of freak wave formation. the fourth - order current - modified nonlinear schr \ " odinger equation ( cnls4 ) is employed to describe the wave evolution. by solving cnls4 numerically, we are able to obtain quantitative predictions for the wave height distribution as a function of key environmental conditions such as average steepness, angular spread, and frequency spread of the local sea state. additionally, we explore the spatial dependence of the wave height distribution, associated with the buildup of nonlinear development.
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arxiv:1207.2130
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this paper aims to mitigate straggler effects in synchronous distributed learning for multi - agent reinforcement learning ( marl ) problems. stragglers arise frequently in a distributed learning system, due to the existence of various system disturbances such as slow - downs or failures of compute nodes and communication bottlenecks. to resolve this issue, we propose a coded distributed learning framework, which speeds up the training of marl algorithms in the presence of stragglers, while maintaining the same accuracy as the centralized approach. as an illustration, a coded distributed version of the multi - agent deep deterministic policy gradient ( maddpg ) algorithm is developed and evaluated. different coding schemes, including maximum distance separable ( mds ) code, random sparse code, replication - based code, and regular low density parity check ( ldpc ) code are also investigated. simulations in several multi - robot problems demonstrate the promising performance of the proposed framework.
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arxiv:2101.02308
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the number of domino tilings of a region with reflective symmetry across a line is combinatorially shown to depend on the number of domino tilings of particular subregions, modulo 4. this expands upon previous congruency results for domino tilings, modulo 2, and leads to a variety of corollaries, including that the number of domino tilings of a k x 2k rectangle is congruent to 1 mod 4.
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arxiv:0705.1300
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in this work, we adopt wyner common information framework for unsupervised multi - view representation learning. within this framework, we propose two novel formulations that enable the development of computational efficient solvers based on the alternating minimization principle. the first formulation, referred to as the { \ em variational form }, enjoys a linearly growing complexity with the number of views and is based on a variational - inference tight surrogate bound coupled with a lagrangian optimization objective function. the second formulation, i. e., the { \ em representational form }, is shown to include known results as special cases. here, we develop a tailored version from the alternating direction method of multipliers ( admm ) algorithm for solving the resulting non - convex optimization problem. in the two cases, the convergence of the proposed solvers is established in certain relevant regimes. furthermore, our empirical results demonstrate the effectiveness of the proposed methods as compared with the state - of - the - art solvers. in a nutshell, the proposed solvers offer computational efficiency, theoretical convergence guarantees ( local minima ), scalable complexity with the number of views, and exceptional accuracy as compared with the state - of - the - art techniques. our focus here is devoted to the discrete case and our results for continuous distributions are reported elsewhere.
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arxiv:2303.15866
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time series classification problems have drawn increasing attention in the machine learning and statistical community. closely related is the field of functional data analysis ( fda ) : it refers to the range of problems that deal with the analysis of data that is continuously indexed over some domain. while often employing different methods, both fields strive to answer similar questions, a common example being classification or regression problems with functional covariates. we study methods from functional data analysis, such as functional generalized additive models, as well as functionality to concatenate ( functional - ) feature extraction or basis representations with traditional machine learning algorithms like support vector machines or classification trees. in order to assess the methods and implementations, we run a benchmark on a wide variety of representative ( time series ) data sets, with in - depth analysis of empirical results, and strive to provide a reference ranking for which method ( s ) to use for non - expert practitioners. additionally, we provide a software framework in r for functional data analysis for supervised learning, including machine learning and more linear approaches from statistics. this allows convenient access, and in connection with the machine - learning toolbox mlr, those methods can now also be tuned and benchmarked.
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arxiv:1911.07511
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batch effects are pervasive in biomedical studies. one approach to address the batch effects is repeatedly measuring a subset of samples in each batch. these remeasured samples are used to estimate and correct the batch effects. however, rigorous statistical methods for batch effect correction with remeasured samples are severely under - developed. in this study, we developed a framework for batch effect correction using remeasured samples in highly confounded case - control studies. we provided theoretical analyses of the proposed procedure, evaluated its power characteristics, and provided a power calculation tool to aid in the study design. we found that the number of samples that need to be remeasured depends strongly on the between - batch correlation. when the correlation is high, remeasuring a small subset of samples is possible to rescue most of the power.
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arxiv:2311.03289
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basics of neutrino oscillations is discussed. importance of time - energy uncertainty relation is stressed. neutrino oscillations in the leading approximation and evidence for neutrino oscillations are briefly summarized.
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arxiv:hep-ph/0510175
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we study the dynamics of an electron wave - packet in a two - dimensional square lattice with an aperiodic site potential in the presence of an external uniform electric field. the aperiodicity is described by $ \ epsilon _ { \ bf m } = v \ cos { ( \ pi \ alpha m _ x ^ { \ nu _ x } ) } \ cos { ( \ pi \ alpha m _ y ^ { \ nu _ y } ) } $ at lattice sites $ ( m _ x, m _ y ) $, with $ \ pi \ alpha $ being a rational number, and $ \ nu _ x $ and $ \ nu _ y $ tunable parameters, controlling the aperiodicity. using an exact diagonalization procedure and a finite - size scaling analysis, we show that in the weakly aperiodic regime ( $ \ nu _ x, \ nu _ y < 1 $ ), a phase of extended states emerges in the center of the band at zero field giving support to a macroscopic conductivity in the thermodynamic limit. turning on the field gives rise to bloch oscillations of the electron wave - packet. the spectral density of these oscillations may display a double peak structure signaling the spatial anisotropy of the potential landscape. the frequency of the oscillations can be understood using a semi - classical approach.
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arxiv:0809.3362
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the combined effect of tidal forcing and aquifer heterogeneity leads to intricate transport patterns in coastal aquifers that impact both on solute residence times and mixing dynamics. we study these patterns through detailed numerical simulations of density - dependent flow and transport in a three - dimensional heterogeneous coastal aquifer under tidal forcing. advective particle tracking from both the freshwater and seawater domains reveals the formation of chaotic and periodic orbits in the freshwater - saltwater transition zone that may persistently trap contaminants. we find that increasing heterogeneity results in increased trapping, but also increased mixing entropy, which suggests that the chaotic orbits enhance mixing between contaminants from the freshwater and seawater domains. these findings highlight on the one hand, the long - term contamination risks of coastal aquifers through trapping, and on the other hand, the creation of hotspots for chemical and biological reactions through chaotic mixing in the transition zone.
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arxiv:2503.02516
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in many state - of - the - art compression systems, signal transformation is an integral part of the encoding and decoding process, where transforms provide compact representations for the signals of interest. this paper introduces a class of transforms called graph - based transforms ( gbts ) for video compression, and proposes two different techniques to design gbts. in the first technique, we formulate an optimization problem to learn graphs from data and provide solutions for optimal separable and nonseparable gbt designs, called gl - gbts. the optimality of the proposed gl - gbts is also theoretically analyzed based on gaussian - markov random field ( gmrf ) models for intra and inter predicted block signals. the second technique develops edge - adaptive gbts ( ea - gbts ) in order to flexibly adapt transforms to block signals with image edges ( discontinuities ). the advantages of ea - gbts are both theoretically and empirically demonstrated. our experimental results demonstrate that the proposed transforms can significantly outperform the traditional karhunen - loeve transform ( klt ).
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arxiv:1909.00952
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we study cryptography based on operator theory, and propose quantum no - key ( qnk ) protocols from the perspective of operator theory, then present a framework of qnk protocols. the framework is expressed in two forms : trace - preserving quantum operators and natural presentations. then we defined the information - theoretical security of qnk protocols and the security of identification keys. two kinds of qnk protocols are also proposed. the first scheme is constructed based on unitary transformation, and the other is constructed based on two multiplicative commutative sets.
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arxiv:1210.8251
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in the last few years it was realized that every fermionic theory in 1 + 1 dimensions is a generalized jordan - wigner transform of a bosonic theory with a non - anomalous $ \ mathbb { z } _ 2 $ symmetry. in this note we determine how the boundary states are mapped under this correspondence. we also interpret this mapping as the fusion of the original boundary with the fermionization interface.
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arxiv:2103.00746
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we studied the possibility to approximate a lennard jones interaction by a pairwise contact potential. first we used a lennard - jones potential to design off - lattice, protein - like heteropolymer sequences, whose lowest energy ( native ) conformations were then identified by molecular dynamics. then we turned to investigate whether one can find a pairwise contact potential, whose ground states are the contact maps associated with these native conformations. we show that such a requirement cannot be satisfied exactly - i. e. no such contact parameters exist. nevertheless, we found that one can find contact energy parameters for which an energy minimization procedure, acting in the space of contact maps, yields maps whose corresponding structures are close to the native ones. finally we show that when these structures are used as the initial point of a molecular dynamics energy minimization process, the correct native folds are recovered with high probability.
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arxiv:cond-mat/9902228
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we successfully demonstrate coexistence of record - high 11. 2 tb / s ( 56x200gb / s ) classical channels with a discrete - variable - qkd channel over a multicore fibre. continuous secret key generation is confirmed together with classical channel performance below the sdfec limit and a minimum quantum channel spacing of 17nm in the c - band.
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arxiv:1907.01459
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two simple predicates are adopted and certain real - valued piecewise continuous functions are constructed from them. this type of maps will be called quasi - step maps and aim to separate the fixed points of an iteration map in an interval. the main properties of these maps are studied. several worked examples are given where appropriate quasi - step maps for newton and halley iteration maps illustrate the main features of quasi - step maps as tools for global separation of roots.
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arxiv:1511.07716
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one of the challenges for stellar astrophysics is to reach the point at which we can undertake reliable spectral synthesis of unresolved populations in young, star - forming galaxies at high redshift. here i summarise recent studies of massive stars in the galaxy and magellanic clouds, which span a range of metallicities commensurate with those in high - redshift systems, thus providing an excellent laboratory in which to study the role of environment on stellar evolution. i also give an overview of observations of luminous supergiants in external galaxies out to a remarkable 6. 7 mpc, in which we can exploit our understanding of stellar evolution to study the chemistry and dynamics of the host systems.
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arxiv:1009.4484
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to measure the spin period of the white dwarf in v1033 cas with high precision, we performed extensive photometry. observations were obtained over 34 nights in 2017. the total duration of the observations was 143 h. we found that the spin period of the white dwarf is equal to 563. 11633 + / - 0. 00010 s. using this period, we derived the oscillation ephemeris with a long validity of 100 years. the spin oscillation semi - amplitude was stable and was equal to 95. 5 + / - 1. 3 mmag. this is a very large semi - amplitude of the spin oscillation among intermediate polars, which have similar and lesser spin periods. this large semi - amplitude suggests that the system is noticeably inclined. the spin pulse profile was sinusoidal with high accuracy. this may mean that the spin oscillation is produced by a single accretion curtain whereas the second accretion curtain may be obscured by the accretion disc. despite the large amount of our observations, we did not detect sidebands. the semi - amplitudes of the undetected sideband oscillations do not exceed 10 mmag. the absence of sideband oscillations seems puzzling. we detected the orbital variability of v1033 cas with a period of 4. 0243 + / - 0. 0028 h and with a semi - amplitude of 55 + / - 4 mmag. the orbital variability semi - amplitude seems large and also suggests that the system is noticeably inclined. using our oscillation ephemeris and the times of spin pulse maximum obtained in the past, we found that the spin period is very stable. dp / dt is most probably less than - 4 x 10 ^ ( - 12 ). this contradicts the assumption that the white dwarf in v1033 cas is not spinning at equilibrium. our spin period and our oscillation ephemeris can be used for further investigations of the stability of the spin period in v1033 cas.
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arxiv:1911.06522
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the distribution of qso radio luminosities has long been debated in the literature. some argue that it is a bimodal distribution, implying that there are two separate qso populations ( normally referred to as ' radio - loud ' and ' radio - quiet ' ), while others claim it forms a more continuous distribution characteristic of a single population. we use deep observations at 20 ghz to investigate whether the distribution is bimodal at high radio frequencies. carrying out this study at high radio frequencies has an advantage over previous studies as the radio emission comes predominantly from the core of the agn, hence probes the most recent activity. studies carried out at lower frequencies are dominated by the large scale lobes where the emission is built up over longer timescales ( 10 ^ 7 - 10 ^ 8 yrs ), thereby confusing the sample. our sample comprises 874 x - ray selected qsos that were observed as part of the 6df galaxy survey. of these, 40 % were detected down to a 3 sigma detection limit of 0. 2 - 0. 5 mjy. no evidence of bimodality is seen in either the 20 ghz luminosity distribution or in the distribution of the r _ 20 parameter : the ratio of the radio to optical luminosities traditionally used to classify objects as being either radio - loud or radio - quiet. previous results have claimed that at low radio luminosities, star formation processes can dominate the radio emission observed in qsos. we attempt to investigate these claims by stacking the undetected sources at 20 ghz and discuss the limitations in carrying out this analysis. however, if the radio emission was solely due to star formation processes, we calculate that this corresponds to star formation rates ranging from ~ 10 solar masses / yr to ~ 2300 solar masses / yr.
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arxiv:1205.2233
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we perform both lattice dynamics analysis and molecular dynamics simulations to demonstrate the existence of topologically protected phonon modes in a two - dimensional, monolayer hexagonal boron nitride sheet. the topological phonon modes are found to be localized at an in - plane interface that divides the system into two regions of distinct valley chern numbers. the dispersion of this topological phonon mode crosses over the frequency gap [ 1123, 1278 ] cm ^ { - 1 }, which is opened through analogy with the quantum valley hall effect by breaking inversion symmetry of the boron and nitride atoms in the primitive unit cell. consequently, vibrational energy with frequency within this gap is topologically protected, resulting in wave propagation that exhibits minimal backscattering, is robust with regards to structural defects such as sharp corners, and exhibits excellent temporal stability. our findings open up the possibility of realizing topological phonons and mechanics in two - dimensional nanomaterials.
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arxiv:1712.01449
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underline { \ mathscr { l } } ) $ by schraen.
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arxiv:1902.00699
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this essay provides a comprehensive analysis of the optimization and performance evaluation of various routing algorithms within the context of computer networks. routing algorithms are critical for determining the most efficient path for data transmission between nodes in a network. the efficiency, reliability, and scalability of a network heavily rely on the choice and optimization of its routing algorithm. this paper begins with an overview of fundamental routing strategies, including shortest path, flooding, distance vector, and link state algorithms, and extends to more sophisticated techniques.
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arxiv:2402.15749
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\ textbf { galrotpy } is an educational \ verb + python3 + - based visual tool, which is useful to undestand how is the contribution of each mass component to the gravitational potential of disc - like galaxies by means of their rotation curve. besides, \ textbf { galrotpy } allows the user to perform a parametric fit of a given rotation curve, which relies on a mcmc procedure implemented by using \ verb + emcee + package. here the gravitational potential of disc - like galaxies is built from the contribution of a miyamoto - nagai potential model for the bulge / core and the thin / thick disc, an exponential disc, together with the nfw ( navarro - frenk - white ) potential or the burkert ( cored density profile ) potential for the dark matter halo, where each contribution is implemented by using \ verb + galpy + package. we summarize the properties of each contribution to the rotation curve involved, and then describe how \ textbf { galrotpy } is implemented along with its capabilities. finally we present the characterization of two galaxies, ngc6361 and m33, and show that the results for m33 provided by \ textbf { galrotpy } are consistent with those found in the literature.
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arxiv:1705.01665
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we present imaging and spectroscopic observations of the gravitationally lensed arcs in the field of rx j1347. 5 - 1145, the most x - ray luminous galaxy cluster known. based on the detection of the [ oii ] 3727 emission line, we confirm that the redshift of one of the arcs is z = 0. 806. its color and [ oii ] line strength are consistent with those of distant, actively star forming galaxies. in a second arc, we tentatively identify a pair of absorption lines superposed on a red continuum ; the lines are consistent with ca ii h & k at z = 0. 785. we detected a faint blue continuum in two additional arcs, but no spectral line features could be measured. we establish lower limits to their redshifts based on the absence of [ oii ] emission, which we argue should be present and detectable in these objects. redshifts are also given for a number of galaxies in the field of the cluster.
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arxiv:astro-ph/0206424
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the lora physical layer is one of the most promising low power wide - area network ( lpwan ) technologies for future internet of things ( iot ) applications. it provides a flexible adaptation of coverage and data rate by allocating different spreading factors ( sfs ) and transmit powers to end - devices. we focus on improving throughput fairness while reducing energy consumption. whereas most existing methods assume perfect sf orthogonality and ignore the harmful effects of inter - sf interferences, we formulate a joint sf and power allocation problem to maximize the minimum uplink throughput of end - devices, subject to co - sf and inter - sf interferences, and power constraints. this results into a mixed - integer non - linear optimization, which, for tractability, is split into two sub - problems : firstly, the sf assignment for fixed transmit powers, and secondly, the power allocation given the previously obtained assignment solution. for the first sub - problem, we propose a low - complexity many - to - one matching algorithm between sfs and end - devices. for the second one, given its intractability, we transform it using two types of constraints approximation : a linearized and a quadratic version. our performance evaluation demonstrates that the proposed joint sf allocation and power optimization enables to drastically enhance various performance objectives such as throughput, fairness and power consumption, and that it outperforms baseline schemes.
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arxiv:1904.11303
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as the overlap between traditional computational mechanics and machine learning grows, there is an increasing demand for straight - forward approaches to interface python - based procedures with c + + - based openfoam. this article introduces one such general methodology, allowing the execution of python code directly within an openfoam solver without the need for python code translation. the proposed approach is based on the lightweight library pybind11, where openfoam data is transferred to an embedded python interpreter for manipulation, and results are returned as needed. following a review of related approaches, the article describes the approach, with a particular focus on data transfer between python and openfoam, executing python scripts and functions, and practical details about the implementation in openfoam. three complementary test cases are presented to highlight the functionality and demonstrate the effect of different data transfer approaches : a python - based velocity profile boundary condition ; a python - based solver for prototyping ; and a machine learning mechanical constitutive law class for solids4foam which performs field calculations.
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arxiv:2203.16394
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optimal decision - making is key to efficient allocation and scheduling of repair resources ( e. g., crews ) to service affected nodes of large power grid networks. traditional manual restoration methods are inadequate for modern smart grids sprawling across vast territories, compounded by the unpredictable nature of damage and disruptions in power and transportation networks. this paper develops a method that focuses on the restoration and repair efforts within power systems. we expand upon the methodology proposed in the literature and incorporate a real - world transportation network to enhance the realism and practicality of repair schedules. our approach carefully devises a reduced network that combines vulnerable components from the distribution network with the real transportation network. key contributions include dynamically addressing a coupled resource allocation and capacitated vehicle routing problem over a new reduced network model, constructed by integrating the power grid with the transportation network. this is performed using network heuristics and graph theory to prioritize securing critical grid segments. a case study is presented for the 8500 bus system.
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arxiv:2404.13422
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- linear variances at both scales as two free parameters. especially, such an analysis could simultaneously measure $ f _ { \ mathrm { nl } } $ and the amplitude and slope of the non - linear power spectrum. however, at 15mpc / $ h $ our predictions are only accurate to $ \ lesssim 0. 8 \ % $ for the considered density range. we discuss how this has to be improved in order to push to these small scales and make full use of upcoming surveys with a pdf - based analysis.
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arxiv:1912.06621
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we construct many new cyclic ( v ; r, s ; lambda ) difference families with v less than or equal 50. in particular we construct the difference families with parameters ( 45 ; 18, 10 ; 9 ), ( 45 ; 22, 22 ; 21 ), ( 47 ; 21, 12 ; 12 ), ( 47 ; 19, 15 ; 12 ), ( 47 ; 22, 14 ; 14 ), ( 48 ; 20, 10 ; 10 ), ( 48 ; 24, 4 ; 12 ), ( 50 ; 25, 20 ; 20 ) for which the existence question was an open problem. the ( 45 ; 22, 22 ; 21 ) difference family gives a bibd with parameters v = 45, b = 90, r = 44, k = 22 and lambda = 21, and the one with parameters ( 50 ; 25, 20 ; 20 ) gives a pair of binary sequences of length 50 with zero periodic autocorrelation function ( the periodic analog of a golay pair ). we also construct nine new d - optimal designs. a normal form for cyclic difference families is proposed and used effectively in compiling the list of known and new difference families.
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arxiv:0707.2173
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let $ m $ be a positive integer and $ q $ be a prime power. for large finite base fields $ \ mathbb f _ q $, we show that any curve can be used to produce a complete $ m $ - arc as long as some generic explicit geometric conditions on the curve are verified. to show the effectiveness of our theory, we derive complete $ m $ - arcs from hyperelliptic curves and from artin - schreier curves.
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arxiv:2303.13670
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a rotating black hole causes the spin - axis of a nearby pulsar to precess due to geodetic and gravitomagnetic frame - dragging effects. the aim of our theoretical work here is to explore how this spin - precession can modify the rate at which pulses are received on earth. towards this end, we obtain the complete evolution of the beam vectors of pulsars moving on equatorial circular orbits in the kerr spacetime, relative to asymptotic fixed observers. we proceed to establish that such spin - precession effects can significantly modify observed pulse frequencies and, in specific, we find that the observed pulse frequency rises sharply as the orbit shrinks, potentially providing a new way to locate horizons of kerr black holes, even if observed for a very short time period. we also discuss implications for detections of sub - millisecond pulsars, pulsar nulling, quasi - periodic oscillations, multiply - peaked pulsar fourier profiles and how kerr black holes can potentially be distinguished from naked singularities.
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arxiv:1711.04053
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we generalize the notion of metallic structure in the pseudo - riemannian setting, define the metallic norden structure and study its integrability. we consider metallic maps between metallic manifolds and give conditions under which they are constant. we also construct a metallic natural connection recovering as particular case the ganchev and mihova connection, which we extend to a metallic natural connection on the generalized tangent bundle. moreover, we construct metallic pseudo - riemannian structures on the tangent and cotangent bundles.
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arxiv:1811.10406
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we complete the ` paraxial ' ( small - angle ) ray optics cloaking formalism presented previously [ choi and howell, opt. express 22, 29465 ( 2014 ) ], by extending it to the full - field of light. omnidirectionality is then the only relaxed parameter of what may be considered an ideal, broadband, field cloak. we show that an isotropic plate of uniform thickness, with appropriately designed refractive index and dispersion, can match the phase over the whole visible spectrum. our results support the fundamental limits on cloaking for broadband vs. omnidirectionality, and provide insights into when anisotropy may be required.
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arxiv:1506.01464
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the redshifted 21cm line of neutral hydrogen ( hi ), potentially observable at low radio frequencies ( ~ 50 - 200 mhz ), is a promising probe of the physical conditions of the inter - galactic medium during cosmic dawn and the epoch of reionisation ( eor ). the sky - averaged hi signal is expected to be extremely weak ( ~ 100 mk ) in comparison to the galactic foreground emission ( ~ $ 10 ^ 4 $ k ). moreover, the sky - averaged spectra measured by ground - based instruments are affected by chromatic propagation effects ( of the order of tens of kelvins ) originating in the ionosphere. we analyze data collected with the upgraded bighorns system deployed at the murchison radio - astronomy observatory to assess the significance of ionospheric effects ( absorption, emission and refraction ) on the detection of the global eor signal. we measure some properties of the ionosphere, such as the electron temperature ( $ t _ e \ approx $ 470 k at nighttime ), magnitude, and variability of optical depth ( $ \ tau _ { 100 mhz } \ approx $ 0. 01 and $ \ delta \ tau \ approx $ 0. 005 at nighttime ). according to the results of a statistical test applied on a large data sample, very long integrations lead to increased signal to noise even in the presence of ionospheric variability. this is further supported by the structure of the power spectrum of the sky temperature fluctuations, which has flicker noise characteristics at frequencies $ \ gtrsim 10 ^ { - 5 } $ hz, but becomes flat below $ \ approx 10 ^ { - 5 } $ hz. we conclude that the stochastic error introduced by the chromatic ionospheric effects tends to zero in an average. therefore, the ionospheric effects and fluctuations are not fundamental impediments preventing ground - based instruments from integrating down to the precision required by global eor experiments.
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arxiv:1509.06125
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discovering crystal structures with specific chemical properties has become an increasingly important focus in material science. however, current models are limited in their ability to generate new crystal lattices, as they only consider atomic positions or chemical composition. to address this issue, we propose a probabilistic diffusion model that utilizes a geometrically equivariant gnn to consider atomic positions and crystal lattices jointly. to evaluate the effectiveness of our model, we introduce a new generation metric inspired by frechet inception distance, but based on gnn energy prediction rather than inceptionv3 used in computer vision. in addition to commonly used metrics like validity, which assesses the plausibility of a structure, this new metric offers a more comprehensive evaluation of our model ' s capabilities. our experiments on existing benchmarks show the significance of our diffusion model. we also show that our method can effectively learn meaningful representations.
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arxiv:2401.05402
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understanding the representational power of restricted boltzmann machines ( rbms ) with multiple layers is an ill - understood problem and is an area of active research. motivated from the approach of \ emph { inherent structure formalism } ( stillinger & weber, 1982 ), extensively used in analysing spin glasses, we propose a novel measure called \ emph { inherent structure capacity } ( isc ), which characterizes the representation capacity of a fixed architecture rbm by the expected number of modes of distributions emanating from the rbm with parameters drawn from a prior distribution. though isc is intractable, we show that for a single layer rbm architecture isc approaches a finite constant as number of hidden units are increased and to further improve the isc, one needs to add a second layer. furthermore, we introduce \ emph { lean } rbms, which are multi - layer rbms where each layer can have at - most $ o ( n ) $ units with the number of visible units being n. we show that for every single layer rbm with $ \ omega ( n ^ { 2 + r } ), r \ ge 0 $, hidden units there exists a two - layered \ emph { lean } rbm with $ \ theta ( n ^ 2 ) $ parameters with the same isc, establishing that 2 layer rbms can achieve the same representational power as single - layer rbms but using far fewer number of parameters. to the best of our knowledge, this is the first result which quantitatively establishes the need for layering.
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arxiv:1806.04577
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indications are presented for a significant connection between the relative motion of the planets and the appearance of energetic solar flares. based on the records of the last four decades, the analysis highlights remarkable features and a lack of randomness in the data. the indications are supported further by the predictive power of a preliminary application to forecasting with machine learning methods.
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arxiv:2006.10694
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in this work, we prove that any symplectic matrix can be factored into no more than 9 unit triangular symplectic matrices. this structure - preserving factorization of the symplectic matrices immediately reveals two well - known features that, ( i ) the determinant of any symplectic matrix is one, ( ii ) the matrix symplectic group is path connected, as well as a new feature that ( iii ) all the unit triangular symplectic matrices form a set of generators of the matrix symplectic group. furthermore, this factorization yields effective methods for the unconstrained parametrization of the matrix symplectic group as well as its structured subsets. the unconstrained parametrization enables us to apply faster and more efficient unconstrained optimization algorithms to the problems with symplectic constraints under certain circumstances.
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arxiv:1912.10926
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kernel embeddings of distributions have recently gained significant attention in the machine learning community as a data - driven technique for representing probability distributions. broadly, these techniques enable efficient computation of expectations by representing integral operators as elements in a reproducing kernel hilbert space. we apply these techniques to the area of stochastic optimal control theory and present a method to compute approximately optimal policies for stochastic systems with arbitrary disturbances. our approach reduces the optimization problem to a linear program, which can easily be solved via the lagrangian dual, without resorting to gradient - based optimization algorithms. we focus on discrete - time dynamic programming, and demonstrate our proposed approach on a linear regulation problem, and on a nonlinear target tracking problem. this approach is broadly applicable to a wide variety of optimal control problems, and provides a means of working with stochastic systems in a data - driven setting.
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arxiv:2103.12759
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intensional computation derives concrete outputs from abstract function definitions ; extensional computation defines functions through explicit input - output pairs. in formal semantics : intensional computation interprets expressions as context - dependent functions ; extensional computation evaluates expressions based on their denotations in an otherwise fixed context. this paper reformulates typed extensional and intensional models of formal semantics within a category - theoretic framework and demonstrates their natural representation therein. we construct $ \ textbf { modint } $, the category of intensional models, building on the categories $ \ textbf { set } $ of sets, $ \ textbf { rel } $ of relations, and $ \ textbf { kr } $ and $ \ textbf { kr } _ \ textbf { b } $ of kripke frames with monotone maps and bounded morphisms, respectively. we prove that trivial intensional models are equivalent to extensional models, providing a unified categorical representation of intensionality and extensionality in formal semantics. this approach reinterprets the relationship between intensions and extensions in a categorical framework and offers a modular, order - independent method for processing intensions and recovering extensions ; contextualizing the relationship between content and reference in category - theoretic terms. we discuss implications for natural language semantics and propose future directions for contextual integration and exploring $ \ textbf { modint } $ ' s algebraic properties.
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arxiv:2408.07058
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in this paper, we continue to build support for the proposal to use gamma - ray bursts ( grbs ) as standard candles in constructing the hubble diagram at redshifts beyond the current reach of type ia supernova observations. we confirm that correlations among certain spectral and lightcurve features can indeed be used as luminosity indicators, and demonstrate from the most up - to - date grb sample appropriate for this work that the $ \ lambda $ cdm model optimized with these data is characterized by parameter values consistent with those in the concordance model. specifically, we find that $ ( \ omega _ m, \ omega _ \ lambda ) \ approx ( 0. 25 _ { - 0. 06 } ^ { + 0. 05 }, 0. 75 _ { - 0. 05 } ^ { + 0. 06 } ) $, which are consistent, to within $ 1 \ sigma $, with $ ( 0. 29, 0. 71 ) $ obtained from the 9 - yr wmap data. we also carry out a comparative analysis between $ \ lambda $ cdm and the $ r _ { \ rm h } = ct $ universe and find that the optimal $ \ lambda $ cdm model fits the grb hubble diagram with a reduced $ \ chi ^ 2 _ { \ rm dof } \ approx 2. 26 $, whereas the fit using $ r _ { \ rm h } = ct $ results in a $ \ chi ^ 2 _ { \ rm dof } \ approx 2. 14 $. in both cases, about 20 % of the events lie at least $ 2 \ sigma $ away from the best - fit curves, suggesting that either some contamination by non - standard grb luminosities is unavoidable, or that the errors and intrinsic scatter associated with the data are being underestimated. with these optimized fits, we use three statistical tools - - - the akaike information criterion ( aic ), the kullback information criterion ( kic ), and the bayes information criterion ( bic ) - - - to show that, based on the grb hubble diagram, the likelihood of $ r _ { \ rm h } = ct $ being closer to the correct model is $ \ sim 85 - 96 % $, compared to $ \ sim 4 - 15 % $ for $ \ lambda $ cdm.
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arxiv:1301.0894
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many consumer technologies and scientific methods rely on photodetection of infrared light. we report a schottky photodetector operating below silicon ' s band gap energy, through hot carrier injection from a nanoscale metallic absorber. our design relies on simple cmos - compatible ' bottom up ' fabrication of fractally nanostructured aluminium films. due to the fractal nature of the nanostructuring, the aluminium films support plasmonically enhanced absorption over a wide wavelength range. we demonstrate two orders of magnitude improvements of responsivity, noise - equivalent - power, and detectivity as compared to bulk metal, over a broad spectral and angular range. we attribute this to momentum relaxation processes from the nanoscale fractal geometry. specifically, we demonstrate a direct link between quantum efficiency enhancement and structural parameters such as perimeter to surface ratio. finally, our devices also function as bulk refractive index sensors. our approach is a promising candidate for future cost effective and robust short wave infrared photodetection and sensing applications.
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arxiv:1909.12675
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we have developed fft beamforming techniques for the chime radio telescope, to search for and localize the astrophysical signals from fast radio bursts ( frbs ) over a large instantaneous field - of - view ( fov ) while maintaining the full angular resolution of chime. we implement a hybrid beamforming pipeline in a gpu correlator, synthesizing 256 fft - formed beams in the north - south direction by four formed beams along east - west via exact phasing, tiling a sky area of ~ 250 square degrees. a zero - padding approximation is employed to improve chromatic beam alignment across the wide bandwidth of 400 to 800 mhz. we up - channelize the data in order to achieve fine spectral resolution of $ \ delta \ nu $ = 24 khz and time cadence of 0. 983 ms, desirable for detecting transient and dispersed signals such as those from frbs.
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arxiv:1702.04728
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we study the dynamics of abelian gauge fields invariant under transverse diffeomorphisms ( tdiff ) in cosmological contexts. we show that in the geometric optics approximation, very much as for diff invariant theories, the corresponding massless gauge bosons propagate along null geodesics and particle number is conserved. in addition, the polarization vectors are orthogonal to the propagation direction and the physical ( transverse projection ) polarization is parallel transported along the geodesics. we also consider tdiff invariant dirac spinors, study the coupling to the gauge fields and analyze the conditions in order to avoid violations of einstein ' s equivalence principle. the contributions to the energy - momentum tensor of the gauge field are also analyzed. we find that, in general, the breaking of diff invariance makes the electric and magnetic parts of the vector field to gravitate in a different way. in the sub - hubble regime we recover the standard radiation - like behaviour of the energy density, however in the super - hubble regime the behaviour is totally different to the diff case, thus opening up a wide range of possibilities for cosmological model building. in particular, possible effects on the evolution of large - scale primordial magnetic fields are discussed.
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arxiv:2402.18368
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the weight distribution of second order $ q $ - ary reed - muller codes have been determined by sloane and berlekamp ( ieee trans. inform. theory, vol. it - 16, 1970 ) for $ q = 2 $ and by mceliece ( jpl space programs summary, vol. 3, 1969 ) for general prime power $ q $. unfortunately, there were some mistakes in the computation of the latter one. this paper aims to provide a precise account for the weight distribution of second order $ q $ - ary reed - muller codes. in addition, the weight distributions of second order $ q $ - ary homogeneous reed - muller codes and second order $ q $ - ary projective reed - muller codes are also determined.
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arxiv:1903.08058
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the ' wimp miracle ' for the relic abundance of thermal dark matter motivates weak scale dark matter with renormalizable couplings to standard model particles. we study minimal models with such couplings that explain dark matter as a thermal relic. the models contain a singlet dark matter particle with cubic renormalizable couplings between standard model particles and ' partner ' particles with the same gauge quantum numbers as the standard model particle. the dark matter has spin 0, 1 / 2, or 1, and may or may not be its own antiparticle. each model has 3 parameters : the masses of the dark matter and standard model partners, and the cubic coupling. requiring the correct relic abundance gives a 2 - dimensional parameter space where collider and direct detection constraints can be directly compared. we focus on the case of dark matter interactions with colored particles. we find that collider and direct detection searches are remarkably complementary for these models. direct detection limits for the cases where the dark matter is not its own antiparticle require dark matter masses to be in the multi - tev range, where they are extremely difficult to probe in collider experiments. the models where dark matter is its own antiparticle are strongly constrained by collider searches for monojet and jets + met signals. these models are constrained by direct detection mainly near the limit where the dark matter and partner masses are nearly degenerate, where collider searches become more difficult.
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arxiv:1307.8120
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silicon nanowires are prepared by the method of the two - step metal - assisted wet chemical etching. we have analyzed the structure of solid, rough and porous nanowire surfaces of boron - doped silicon substrates with resistivities of \ rho > 1000 \ omega cm, \ rho = 14 - 23 \ omega cm, \ rho < 0. 01 \ omega cm by scanning electron microscopy and nitrogen gas adsorption. silicon nanowires prepared from highly - doped silicon reveal mesopores on their surface. however, we found a limit for pore formation. pores were only formed by etching below a critical h $ _ 2 $ o $ _ 2 $ concentration ( c $ _ { \ mbox { h } _ 2 \ mbox { o } _ 2 } $ < 0. 3 m ). furthermore, we have determined the pore size distribution in dependence on the etching parameters and characterized the morphology of the pores on the nanowire surface. the pores are in the regime of small mesopores with a mean diameter of 9 - 13 nm. crystal and surface structure of individual mesoporous nanowires have been investigated by transmission electron microscopy. the vibrational properties of nanowire ensembles have been investigated by raman spectroscopy. heavily boron - doped silicon nanowires are highly porous and the remaining single crystalline silicon nanoscale mesh leads to a redshift and a strong asymmetric line broadening for raman scattering by optical phonons at 520 cm $ ^ { - 1 } $. this redshift, { \ lambda } $ _ { \ mbox { si bulk } } $ = 520 cm $ ^ { - 1 } $ $ \ rightarrow $ { \ lambda } $ _ { \ mbox { si nanowire } } $ = 512 cm $ ^ { - 1 } $, hints to a phonon confinement in mesoporous single crystalline silicon nanowire.
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arxiv:1410.3763
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poisoning attacks are a primary threat to machine learning models, aiming to compromise their performance and reliability by manipulating training datasets. this paper introduces a novel attack - outlier - oriented poisoning ( oop ) attack, which manipulates labels of most distanced samples from the decision boundaries. the paper also investigates the adverse impact of such attacks on different machine learning algorithms within a multiclass classification scenario, analyzing their variance and correlation between different poisoning levels and performance degradation. to ascertain the severity of the oop attack for different degrees ( 5 % - 25 % ) of poisoning, we analyzed variance, accuracy, precision, recall, f1 - score, and false positive rate for chosen ml models. benchmarking our oop attack, we have analyzed key characteristics of multiclass machine learning algorithms and their sensitivity to poisoning attacks. our experimentation used three publicly available datasets : iris, mnist, and isic. our analysis shows that knn and gnb are the most affected algorithms with a decrease in accuracy of 22. 81 % and 56. 07 % while increasing false positive rate to 17. 14 % and 40. 45 % for iris dataset with 15 % poisoning. further, decision trees and random forest are the most resilient algorithms with the least accuracy disruption of 12. 28 % and 17. 52 % with 15 % poisoning of the iris dataset. we have also analyzed the correlation between number of dataset classes and the performance degradation of models. our analysis highlighted that number of classes are inversely proportional to the performance degradation, specifically the decrease in accuracy of the models, which is normalized with increasing number of classes. further, our analysis identified that imbalanced dataset distribution can aggravate the impact of poisoning for machine learning models
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arxiv:2411.00519
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the fast advancement of large vision - language models ( lvlms ) has shown immense potential. these models are increasingly capable of tackling abstract visual tasks. geometric structures, particularly graphs with their inherent flexibility and complexity, serve as an excellent benchmark for evaluating these models ' predictive capabilities. while human observers can readily identify subtle visual details and perform accurate analyses, our investigation reveals that state - of - the - art lvlms exhibit consistent limitations in specific visual graph scenarios, especially when confronted with stylistic variations. in response to these challenges, we introduce visgraphvar ( visual graph variability ), a customizable benchmark generator able to produce graph images for seven distinct task categories ( detection, classification, segmentation, pattern recognition, link prediction, reasoning, matching ), designed to systematically evaluate the strengths and limitations of individual lvlms. we use visgraphvar to produce 990 graph images and evaluate six lvlms, employing two distinct prompting strategies, namely zero - shot and chain - of - thought. the findings demonstrate that variations in visual attributes of images ( e. g., node labeling and layout ) and the deliberate inclusion of visual imperfections, such as overlapping nodes, significantly affect model performance. this research emphasizes the importance of a comprehensive evaluation across graph - related tasks, extending beyond reasoning alone. visgraphvar offers valuable insights to guide the development of more reliable and robust systems capable of performing advanced visual graph analysis.
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arxiv:2411.14832
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flat tio $ _ 2 $ layers are deposited by magnetron sputtering on ti / si wafers. the tio $ _ 2 $ surfaces are then sputter - coated with thin au films of a nominal thickness of 0. 5 - 10 nm that are converted by solid - state dewetting into au nanoparticles of tuneable size and spacing ; the au nanoparticle size can be tuned over a broad range, i. e. ca. 3 - 200 nm. the au - decorated tio $ _ 2 $ surfaces enable plasmonic photo - electrochemical water splitting under visible light illumination ( 450 - 750 nm ). the water splitting performance reaches a maximum for tio $ _ 2 $ layers decorated with ~ 30 nm - sized au particles. as expected, optical absorption measurements show a red shift of the plasmonic extinction band with increasing the au nanoparticle size. however, the plasmonic photocurrent is found to peak at ~ 600 nm regardless of the size of the au nanoparticles, i. e. the plasmonic photocurrent band position is size - independent. such a remarkable observation can be ascribed to a hot electron injection cut - off effect.
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arxiv:2005.11306
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deep neural networks ( dnns ) have shown great success in many machine learning tasks. their training is challenging since the loss surface of the network architecture is generally non - convex, or even non - smooth. how and under what assumptions is guaranteed convergence to a \ textit { global } minimum possible? we propose a reformulation of the minimization problem allowing for a new recursive algorithmic framework. by using bounded style assumptions, we prove convergence to an $ \ varepsilon $ - ( global ) minimum using $ \ mathcal { \ tilde { o } } ( 1 / \ varepsilon ^ 3 ) $ gradient computations. our theoretical foundation motivates further study, implementation, and optimization of the new algorithmic framework and further investigation of its non - standard bounded style assumptions. this new direction broadens our understanding of why and under what circumstances training of a dnn converges to a global minimum.
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arxiv:2202.03524
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about the reachability of those ip addresses using the border gateway protocol. typically, the human - readable names of servers are translated to ip addresses, transparently to users, via the directory function of the domain name system ( dns ). over the internet, there can be business - to - business, business - to - consumer and consumer - to - consumer communications. when money or sensitive information is exchanged, the communications are apt to be protected by some form of communications security mechanism. intranets and extranets can be securely superimposed onto the internet, without any access by general internet users and administrators, using secure vpn technology. = = see also = = = = references = = this article incorporates public domain material from federal standard 1037c. general services administration. archived from the original on 2022 - 01 - 22. = = further reading = = kurose james f and keith w. ross : computer networking : a top - down approach featuring the internet, pearson education 2005. william stallings, computer networking with internet protocols and technology, pearson education 2004. dimitri bertsekas, and robert gallager, " data networks, " prentice hall, 1992.
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https://en.wikipedia.org/wiki/Computer_network
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existing anchor - based and anchor - free object detectors in multi - stage or one - stage pipelines have achieved very promising detection performance. however, they still encounter the design difficulty in hand - crafted 2d anchor definition and the learning complexity in 1d direct location regression. to tackle these issues, in this paper, we propose a novel detector coined as scopenet, which models anchors of each location as a mutually dependent relationship. this approach quantizes the prediction space and employs a coarse - to - fine strategy for localization. it achieves superior flexibility as in the regression based anchor - free methods, while produces more precise prediction. besides, an inherit anchor selection score is learned to indicate the localization quality of the detection result, and we propose to better represent the confidence of a detection box by combining the category - classification score and the anchor - selection score. with our concise and effective design, the proposed scopenet achieves state - of - the - art results on coco
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arxiv:2005.04854
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let $ ( t \ _ \ lambda ) \ _ { \ lambda \ in \ lambda } $ be a family of operators acting on a $ f $ - space $ x $, where the parameter space $ \ lambda $ is a subset of $ \ mathbb r ^ d $. we give sufficient conditions on the family to yield the existence of a vector $ x \ in x $ such that, for any $ \ lambda \ in \ lambda $, the set $ \ big \ { t \ _ \ lambda ^ n x ; \ n \ geq 1 \ big \ } $ is dense in $ x $. we obtain results valid for any value of $ d \ geq 1 $ whereas the previously known results where restricted to $ d = 1 $. our methods also shed new light on the one - dimensional case.
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arxiv:1503.08574
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predicting the occurrence of links is a fundamental problem in networks. in the link prediction problem we are given a snapshot of a network and would like to infer which interactions among existing members are likely to occur in the near future or which existing interactions are we missing. although this problem has been extensively studied, the challenge of how to effectively combine the information from the network structure with rich node and edge attribute data remains largely open. we develop an algorithm based on supervised random walks that naturally combines the information from the network structure with node and edge level attributes. we achieve this by using these attributes to guide a random walk on the graph. we formulate a supervised learning task where the goal is to learn a function that assigns strengths to edges in the network such that a random walker is more likely to visit the nodes to which new links will be created in the future. we develop an efficient training algorithm to directly learn the edge strength estimation function. our experiments on the facebook social graph and large collaboration networks show that our approach outperforms state - of - the - art unsupervised approaches as well as approaches that are based on feature extraction.
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arxiv:1011.4071
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we show that a strong ` spin ' - orbit coupled one - dimensional ( 1d ) hole gas is achievable via applying a strong magnetic field to the original two - fold degenerate ( spin degeneracy ) hole gas confined in a cylindrical ge nanowire. both strong longitudinal and strong transverse magnetic fields are feasible to achieve this goal. based on quasi - degenerate perturbation calculations, we show the induced low - energy subband dispersion of the hole gas can be written as $ e = \ hbar ^ { 2 } k ^ { 2 } _ { z } / ( 2m ^ { * } _ { h } ) + \ alpha \ sigma ^ { z } k _ { z } + g ^ { * } _ { h } \ mu _ { b } b \ sigma ^ { x } / 2 $, a form exactly the same as that of the electron gas in the conduction band. here the pauli matrices $ \ sigma ^ { z, x } $ represent a pseudo spin ( or ` spin ' ), because the real spin degree of freedom has been split off from the subband dispersions by the strong magnetic field. also, for a moderate nanowire radius $ r = 10 $ nm, the induced effective hole mass $ m ^ { * } _ { h } $ ( $ 0. 065 \ sim0. 08 ~ m _ { e } $ ) and the ` spin ' - orbit coupling $ \ alpha $ ( $ 0. 35 \ sim0. 8 $ ev ~ \ aa ) have a small magnetic field dependence in the studied magnetic field interval $ 1 < b < 15 $ t, while the effective $ g $ - factor $ g ^ { * } _ { h } $ of the hole ` spin ' only has a small magnetic field dependence in the large field region.
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arxiv:2107.00899
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outer envelopes of neutron stars consist mostly of fully ionized, strongly coupled coulomb plasmas characterized by typical densities about 10 ^ 4 - 10 ^ { 11 } g / cc and temperatures about 10 ^ 4 - 10 ^ 9 k. many neutron stars possess magnetic fields about 10 ^ { 11 } - 10 ^ { 14 } g. here we briefly review recent theoretical advances which allow one to calculate thermodynamic functions and electron transport coefficients for such plasmas with an accuracy required for theoretical interpretation of observations.
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arxiv:astro-ph/0012316
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privacy personas capture the differences in user segments with respect to one ' s knowledge, behavioural patterns, level of self - efficacy, and perception of the importance of privacy protection. modelling these differences is essential for appropriately choosing personalised communication about privacy ( e. g. to increase literacy ) and for defining suitable choices for privacy enhancing technologies ( pets ). while various privacy personas have been derived in the literature, they group together people who differ from each other in terms of important attributes such as perceived or desired level of control, and motivation to use pet. to address this lack of granularity and comprehensiveness in describing personas, we propose eight personas that we derive by combining qualitative and quantitative analysis of the responses to an interactive educational questionnaire. we design an analysis pipeline that uses divisive hierarchical clustering and boschloo ' s statistical test of homogeneity of proportions to ensure that the elicited clusters differ from each other based on a statistical measure. additionally, we propose a new measure for calculating distances between questionnaire responses, that accounts for the type of the question ( closed - vs open - ended ) used to derive traits. we show that the proposed privacy personas statistically differ from each other. we statistically validate the proposed personas and also compare them with personas in the literature, showing that they provide a more granular and comprehensive understanding of user segments, which will allow to better assist users with their privacy needs.
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arxiv:2410.14023
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the present study is concerned with the following schr \ " { o } dinger - poisson system involving critical nonlocal term $ $ \ left \ { \ begin { array } { ll } - \ delta u + u - k ( x ) \ phi | u | ^ 3u = \ lambda f ( x ) | u | ^ { q - 2 } u, & x \ in \ mathbb { r } ^ 3, - \ delta \ phi = k ( x ) | u | ^ 5, & x \ in \ mathbb { r } ^ 3, \ \ \ end { array } \ right. $ $ where $ 1 < q < 2 $ and $ \ lambda > 0 $ is a parameter. under suitable assumptions on $ k ( x ) $ and $ f ( x ) $, there exists $ \ lambda _ 0 = \ lambda _ 0 ( q, s, f, k ) > 0 $ such that for any $ \ lambda \ in ( 0, \ lambda _ 0 ) $, the above schr \ " { o } dinger - poisson system possesses at least two positive solutions by standard variational method, where a positive least energy solution will also be obtained.
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arxiv:1702.03792
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for the fifth painlev \ ' e equation it is known that a general solution is represented asymptotically by an elliptic function in cheese - like strips near the point at infinity. we present an explicit asymptotic formula for the error term of this expression, which leads to an estimate for its magnitude as was conjectured. analogous formula is obtained for the error term of the correction function associated with the lagrangian.
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arxiv:2307.01424
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the general class of the graded lie algebras is defined. these algebras could be constructed using an arbitrary dynamical systems with discrete time and with invarinat measure. in this papers we consider the case of the central extension of lie algebras which corresponds to the ordinary crossed product ( as associative algebra ) - series a. the structure of those lie algebras is similar to kac - moody algebras, and these are a special case of so called algebras with continuous root system which were introduced by author with m. saveliev in 90 - th. the central extension open a new possibilty in algebraic theory of dynamical systems. the simpliest example corresponds to rotation of the circle ( sine - algebra = " quantum torus " ) and to adding of unity the additvie group of the p - adic integers.
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arxiv:math/0203018
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already in the cornerstone works on astrophysical black holes published as early as in 1970s, ruffini and collaborators have revealed potential importance of an intricate interaction between the effects of strong gravitational and electromagnetic fields. close to the event horizon of the black hole, magnetic and electric lines of force become distorted and dragged even a in purely electro - vacuum system. moreover, as the plasma effects inevitably arise in any astrophysically realistic environment, particles of different electric charge can separate from each other, become accelerated away from the black hole or accreted onto it, and contribute to the net electric charge of the black hole. from the point of principle, the case of super - strong magnetic fields is of particular interest, as the electromagnetic field can act as a source of gravity and influence the space - time geometry. in a brief celebratory note we revisit aspects of rotation and charge within the framework of exact ( asymptotically non - flat ) solutions of mutually coupled einstein - maxwell equations that describe magnetized, rotating black holes.
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arxiv:2306.07804
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we present ab initio two - dimensional extended hubbard - type multiband models for etme _ 3sb [ pd ( dmit ) _ 2 ] _ 2 and \ kappa - ( bedt - ttf ) _ 2cu ( ncs ) _ 2, after a downfolding scheme based on the constrained random phase approximation ( crpa ) and maximally - localized wannier orbitals, together with the dimensional downfolding. in the pd ( dmit ) _ 2 salt, the antibonding state of the highest occupied molecular orbital ( homo ) and the bonding / antibonding states of the lowest unoccupied molecular orbital ( lumo ) are considered as the orbital degrees of freedom, while, in the \ kappa - bedt - ttf salt, the homo - antibonding / bonding states are considered. accordingly, a three - band model for the pd ( dmit ) _ 2 salt and a two - band model for the \ kappa - ( bedt - ttf ) salt are derived. we derive single band models for the homo - antibonding state for both of the compounds as well.
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arxiv:1208.3954
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