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the stability of lattice boltzmann equations modelling shallow water equations in the special case of reduced gravity is investigated theoretically. a stability notion is defined as applied in incompressible navier - stokes equations in banda, m. k., yong, w. - a. and klar, a : a stability notion for lattice boltzmann equations. siam j. sci. comput. { \ bf 27 ( 6 ) }, 2098 - 2111 ( 2006 ). it is found that to maintain stability a careful choice of the value of the reduced gravity must be made. the stability notion is employed to investigate different shallow water lattice boltzmann equations. results are tested using the lattice boltzmann method for various values of the governing parameters of the flow. it is observed that even for the discrete model the reduced gravity has a significant effect on the stability. | arxiv:1511.04572 |
6d object pose estimation is a fundamental component in robotics enabling efficient interaction with the environment. it is particularly challenging in bin - picking applications, where many objects are low - feature and reflective, and self - occlusion between objects of the same type is common. we propose a novel multi - view approach leveraging known camera transformations from an eye - in - hand setup to combine heatmap and keypoint estimates into a probability density map over 3d space. the result is a robust approach that is scalable in the number of views. it relies on a confidence score composed of keypoint probabilities and point - cloud alignment error, which allows reliable rejection of false positives. we demonstrate an average pose estimation error of approximately 0. 5mm and 2 degrees across a variety of difficult low - feature and reflective objects in the robi dataset, while also surpassing the state - of - art correct detection rate, measured using the 10 % object diameter threshold on add error. | arxiv:2303.16833 |
micro - drone β autonomous drone that uses artificial intelligence to swarm with many other perdix drones. project mac β groundbreaking research in operating systems, artificial intelligence, and the theory of computation. darpa funded project. radar β developed at mit ' s radiation laboratory during world war ii. sketchpad β invented by ivan sutherland at mit ( presented in his phd thesis ). it pioneered the way for human β computer interaction ( hci ). sketchpad is considered to be the ancestor of modern computer - aided design ( cad ) programs as well as a major breakthrough in the development of computer graphics in general. visicalc β first spreadsheet computer program for personal computers, originally released for the apple ii by visicorp. mit alumni dan bricklin and bob frankston rented time sharing at night on an mit mainframe computer ( that cost $ 1 / hr for use ). world wide web consortium β founded in 1994 by tim berners - lee, ( w3c ) is the main international standards organization for the world wide web x window system β pioneering architecture - independent system for graphical user interfaces that has been widely used for unix and linux systems. = = = companies and entrepreneurship = = = mit alumni and faculty have founded numerous companies, some of which are shown below : analog devices, 1965, co - founders ray stata, ( sb, sm ) and matthew lorber ( sb ) blackrock, 1988, co - founder bennett golub, ( sb, sm, phd ) bose corporation, 1964, founder amar bose ( sb, phd ) boston dynamics, 1992, founder marc raibert ( phd ) buzzfeed, 2006, co - founder jonah peretti ( sm ) dropbox, 2007, founders drew houston ( sb ) and arash ferdowsi ( drop - out ) hewlett - packard, 1939, co - founder william r. hewlett ( sm ) huffpost, 2005, co - founder jonah peretti ( sm ) intel, 1968, co - founder robert noyce ( phd ) khan academy, 2008, founder salman khan ( sb, sm ) koch industries, 1940, founder fred c. koch ( sb ), sons william ( sb, phd ), david ( sb ) qualcomm, 1985, co - founders irwin m. jacobs ( sm, phd ) and andrew viterbi ( sb, sm ) raytheon, 1922, co - founder vannevar bush ( deng, professor ) renaissance technologies, 1982, founder james simons ( sb ) scale ai, 2016 | https://en.wikipedia.org/wiki/Massachusetts_Institute_of_Technology |
we study the hessian geometry of toric multi - taub - nut metrics and their phase change phenomena via the images of their moment maps. this generalizes an earlier paper on toric gibbons - hawking metrics. | arxiv:1801.06631 |
the knowledge of stellar ages directly impacts the characterization of a planetary system as it puts strong constraints on the moment when the system was born. unfortunately, the determination of precise stellar ages is a very difficult task. different methods can be used to do so ( based on isochrones or chemical element abundances ) but they usually provide large uncertainties. during its evolution a star goes through processes leading to loss of angular momentum but also changes in its magnetic activity. building rotation, magnetic, age relations would be an asset to infer stellar ages model independently. several attempts to build empirical relations between rotation and age ( namely gyrochronology ) were made with a focus on cluster stars where the age determination is easier and for young stars on the main sequence. for field stars, we can now take advantage of high - precision photometric observations where we can perform asteroseismic analyses to improve the accuracy of stellar ages. furthermore, the variability in the light curves allow us to put strong constraints on the stellar rotation and magnetic activity. by combining these precise measurements, we are on the way of understanding and improving relations between magnetic activity, rotation, and age, in particular at different stages of stellar evolution. i will review the status on gyrochronology relationships based on observations of young cluster stars. then i will focus on solar - like stars and describe the inferences on stellar ages, rotation, and magnetism that can be provided by high - quality photometric observations such as the ones of the kepler mission, in particular through asteroseismic analyses. | arxiv:1502.00706 |
in this paper, we consider the principal eigenvalue problem for hormander ' s laplacian on $ r ^ n $. we also study a related semi - linear sub - elliptic equation in the whole $ r ^ n $ and prove that under a suitable condition, we have infinite many positive solutions of the problem. | arxiv:math/0305068 |
solar energetic particles ( seps ) accelerated from shocks driven by coronal mass ejections ( cmes ) are one of the major causes of geomagnetic storms on earth. therefore, it is necessary to predict the occurrence and intensity of such disturbances. for this purpose we analyzed in detail 38 non - interacting halo and partial halo cmes, as seen by the solar and heliospheric observatory / large angle and spectrometric coronagraph ( soho / lasco ), generating seps ( in > 10 mev, > 50 mev, and > 100 mev energy channels ) during the quadrature configuration of the solar terrestrial relations observatory ( stereo ) twin spacecrafts with respect to the earth, which marks the ascending phase of solar cycle 24 ( i. e., 2009 - 2013 ). the main criteria for this selection period is to obtain height - time measurements of the cmes without significant projection effects and in a very large field of view. using the data from stereo / sun earth connection coronal and heliospheric investigation ( stereo / secchi ) images we determined several kinematic parameters and instantaneous speeds of the cmes. first, we compare instantaneous cme speed and mach number versus sep fluxes for events originating at the western and eastern limb we observe high correlation for the western events and anticorrelation for the eastern events. next we investigated instantaneous cme kinematic parameters such as maximum speed, maximum mach number, and the cme speed and mach number at sep peak flux versus sep peak fluxes. highly positive correlation is observed for mach number at sep peak flux for all events. the obtained instantaneous furthermore, we conducted estimates of delay in time and distance between cme, sep, and shock parameters. comparative studies of the considered energy channels of the seps also throw light on the reacceleration of suprathermal seed ions by cme - driven shocks that are pre - accelerated in the magnetic reconnection. | arxiv:2102.12640 |
the goal of this paper is to study yamabe flow on a complete riemannian manifold of bounded geometry with possibly infinite volume. in the case of infinite volume, standard volume normalization of the yamabe flow fails and the flow may not converge. instead, we consider a curvature normalized yamabe flow, and assuming negative scalar curvature, prove its long - time existence and convergence. this extends the results of su \ ' arez - serrato and tapie to a non - compact setting. in the appendix, we specify our analysis of a particular example of manifolds with bounded geometry, namely manifolds with fibered boundary metric. in this case, we obtain stronger estimates for the short - time solution using microlocal methods. | arxiv:2105.14282 |
we use a set of four theoretical navigability indices for street maps to investigate the shape of the resulting street networks, if they are grown by optimizing these indices. the indices compare the performance of simulated navigators ( having a partial information about the surroundings, like humans in many real situations ) to the performance of optimally navigating individuals. we show that our simple greedy shortcut construction strategy generates the emerging structures that are different from real road network, but not inconceivable. the resulting city plans, for all navigation indices, share common qualitative properties such as the tendency for triangular blocks to appear, while the more quantitative features, such as degree distributions and clustering, are characteristically different depending on the type of metrics and routing strategies. we show that it is the type of metrics used which determines the overall shapes characterized by structural heterogeneity, but the routing schemes contribute to more subtle details of locality, which is more emphasized in case of unrestricted connections when the edge crossing is allowed. | arxiv:1205.0537 |
in order to derive the equivalent partial differential equations of a lattice boltzmann scheme, the chapman enskog expansion is very popular in the lattive boltzmann community. a maindrawback of this approach is the fact that multiscale expansions are used without any clearmathematical signification of the various variables and operators. independently of thisframework, the taylor expansion method allows to obtain formally the equivalent partialdifferential equations. in this contribution, we prove that both approaches give identicalresults with acoustic scaling for a very general family of lattice boltzmann schemes and upto fourth order accuracy. examples with a single scalar conservation illustrate our purpose. | arxiv:2302.07535 |
we calculate the quantum mass corrections to the solitons in the c _ 2 ^ ( 1 ) affine toda field theory. we find that the ratio of the masses of the two solitons is not constant. | arxiv:hep-th/9404065 |
automatic coding patient behaviors is essential to support decision making for psychotherapists during the motivational interviewing ( mi ), a collaborative communication intervention approach to address psychiatric issues, such as alcohol and drug addiction. while the behavior coding task has rapidly adapted machine learning to predict patient states during the mi sessions, lacking of domain - specific knowledge and overlooking patient - therapist interactions are major challenges in developing and deploying those models in real practice. to encounter those challenges, we introduce the chain - of - interaction ( coi ) prompting method aiming to contextualize large language models ( llms ) for psychiatric decision support by the dyadic interactions. the coi prompting approach systematically breaks down the coding task into three key reasoning steps, extract patient engagement, learn therapist question strategies, and integrates dyadic interactions between patients and therapists. this approach enables large language models to leverage the coding scheme, patient state, and domain knowledge for patient behavioral coding. experiments on real - world datasets can prove the effectiveness and flexibility of our prompting method with multiple state - of - the - art llms over existing prompting baselines. we have conducted extensive ablation analysis and demonstrate the critical role of dyadic interactions in applying llms for psychotherapy behavior understanding. | arxiv:2403.13786 |
we investigate experimentally and theoretically the third harmonic generated by a double - layer fishnet metamaterial. to unambiguously disclose most notably the influence of the magnetic resonance, the generated third harmonic was measured as a function of the angle of incidence. it is shown experimentally and numerically that when the magnetic resonance is excited by pump beam, the angular dependence of the third harmonic signal has a local maximum at an incidence angle of { \ theta } \ simeq 20 { \ deg }. this maximum is shown to be a fingerprint of the antisymmetric distribution of currents in the gold layers. an analytical model based on the nonlinear dynamics of the electrons inside the gold shows excellent agreement with experimental and numerical results. this clearly indicates the difference in the third harmonic angular pattern at electric and magnetic resonances of the metamaterial. | arxiv:1208.2370 |
optical pump - thz probe spectroscopy is used to investigate the exciton formation dynamics and its intensity dependence in bulk ge. associated with the intra - excitonic 1s - 2p transition, the gradual build - up of an absorption peak around 3. 1 mev ( 0. 75 thz ) signifies the delayed exciton formation after optical pump which is accelerated for higher excitation densities. analyzing the spectral shape of this thz absorption resonance, two distinct resonances are found which are attributed to the mass - anisotropy of l valley electrons via a microscopic theory. | arxiv:1611.06117 |
predicting thermal response in orthopaedic surgery or dental implantation remains a significant challenge. this study aims to find a practical approach for measuring temperature elevation during a bone drilling experiment by analyzing the existing methods. traditionally thermocouple has frequently been used to predict the bone temperature in the drilling process. however, several experimental studies demonstrate that the invasive method using thermocouple is impractical in medical conditions and prefers the thermal infrared ( ir ) camera as a non - invasive method. this work proposes a simplified experimental model that uses the thermocouple to determine temperature rise coupled with the thermal image source approach. furthermore, our new method provides a significant opportunity to calibrate the thermal ir camera by discovering the undetected heat elevation in a workpiece depth. | arxiv:2308.12034 |
personalization is a crucial aspect of many online experiences. in particular, content ranking is often a key component in delivering sophisticated personalization results. commonly, supervised learning - to - rank methods are applied, which suffer from bias introduced during data collection by production systems in charge of producing the ranking. to compensate for this problem, we leverage contextual multi - armed bandits. we propose novel extensions of two well - known algorithms viz. linucb and linear thompson sampling to the ranking use - case. to account for the biases in a production environment, we employ the position - based click model. finally, we show the validity of the proposed algorithms by conducting extensive offline experiments on synthetic datasets as well as customer facing online a / b experiments. | arxiv:2004.13106 |
using the galactica code of benson et al., we obtain quantitative measurements of spheroid - to - disk ratios for a sample of 8839 galaxies observed in the sloan digital sky survey. we carry out extensive tests of this code and of gim2d, finding that they perform similarly in all respects. from the spheroid and disk luminosities, we construct luminosity and stellar mass functions for each component and estimate the relative luminosity and stellar mass densities of disks and spheroids in the local universe. assuming a simple one - to - one mapping between between spheroid mass and the mass of a central supermassive black hole, we provide the most accurate determination so far of the black hole mass function in the local universe. from this, we infer a cosmological mass density of black holes of rho _ bh = 3. 77 + / - 0. 97 x 10 ^ 5 h m _ sun mpc ^ - 3. we compare our results to predictions from current hierarchical models of galaxy formation and these are found to fare well in predicting the qualitative trends observed. we find that stars in disks contribute 35 - 51 % of the local stellar mass density. | arxiv:astro-ph/0612719 |
by resorting to basic features of topological knot theory we propose a ( classical ) cryptographic protocol based on the ` difficulty ' of decomposing complex knots generated as connected sums of prime knots and their mutants. the scheme combines an asymmetric public key protocol with symmetric private ones and is intrinsecally secure against quantum eavesdropper attacks. | arxiv:1010.2055 |
in this paper, we design a system of two symmetrical containers communicated by an aperture, in which a granular gas of glass spheres is created by shaking laterally the whole system in a planetary mill. if the aperture consists in a symmetrical hole, the two halves end up with the same number of grains after some time when initially all particles are into in one of the containers. however, when a funnel - like aperture is used, a robust symmetry breaking is induced : if all the grains are originally deposited in the container facing the wide side 95 % of the grains pass to the opposite side in a relatively small time. | arxiv:1803.08535 |
in this paper, we introduce sutra, multilingual large language model architecture capable of understanding, reasoning, and generating text in over 50 languages. sutra ' s design uniquely decouples core conceptual understanding from language - specific processing, which facilitates scalable and efficient multilingual alignment and learning. employing a mixture of experts framework both in language and concept processing, sutra demonstrates both computational efficiency and responsiveness. through extensive evaluations, sutra is demonstrated to surpass existing models like gpt - 3. 5, llama2 by 20 - 30 % on leading massive multitask language understanding ( mmlu ) benchmarks for multilingual tasks. sutra models are also online llms that can use knowledge from the internet to provide hallucination - free, factual and up - to - date responses while retaining their multilingual capabilities. furthermore, we explore the broader implications of its architecture for the future of multilingual ai, highlighting its potential to democratize access to ai technology globally and to improve the equity and utility of ai in regions with predominantly non - english languages. our findings suggest that sutra not only fills pivotal gaps in multilingual model capabilities but also establishes a new benchmark for operational efficiency and scalability in ai applications. | arxiv:2405.06694 |
v. i. arnold has recently defined the complexity of a sequence of $ n $ zeros and ones with the help of the operator of finite differences. in this paper we describe the results obtained for almost most complicated sequences of elements of a finite field, whose dimension $ n $ is a prime number. we prove that with $ n \ to \ infty $ this property is inherent in almost all sequences, while the values of multiplicative functions possess this property with any $ n $ different from the characteristic of the field. we also describe the prime values of the parameter $ n $ which make the logarithmic function almost most complicated. all these sequences reveal a stronger complexity ; its algebraic sense is quite clear. | arxiv:0710.3451 |
the source of cosmic gamma - ray bursts ( hereafter grbs ) is usually believed to be a stellar mass black hole accreting material from a thick disk. the mechanism for the production of a relativistic wind by such a system is still unknown. we investigate here one of the proposal where the disk energy is extracted by a magnetic field amplified to very large values b \ sim 10 ^ 15 g. using some very simple assumptions we compute the mass loss rate along magnetic field lines and then estimate the lorentz factor \ gamma at infinity. we find that \ gamma can reach high values only if severe constraints on the field geometry and the conditions of energy injection are satisfied. we discuss the results in the context of different scenarios for grbs. | arxiv:astro-ph/9912444 |
integrated sensing and communication ( isac ) unifies wireless communication and sensing by sharing spectrum and hardware, which often incurs trade - offs between two functions due to limited resources. however, this paper shifts focus to exploring the synergy between communication and sensing, using wifi sensing as an exemplary scenario where communication signals are repurposed to probe the environment without dedicated sensing waveforms, followed by data uploading to the edge server for inference. while increased device participation enhances multi - view sensing data, it also imposes significant communication overhead between devices and the edge server. to address this challenge, we aim to maximize the sensing task performance, measured by mutual information, under the channel capacity constraint. the information - theoretic optimization problem is solved by the proposed ade - mi, a novel framework that employs a two - stage optimization two - stage optimization approach : ( 1 ) adaptive distributed encoding ( ade ) at the device, which ensures transmitted bits are most relevant to sensing tasks, and ( 2 ) multi - view inference ( mi ) at the edge server, which orchestrates multi - view data from distributed devices. our experimental results highlight the synergy between communication and sensing, showing that more frequent communication from wifi access points to edge devices improves sensing inference accuracy. the proposed ade - mi achieves 92 \ % recognition accuracy with over $ 10 ^ 4 $ - fold reduction in latency compared to schemes with raw data communication, achieving both high sensing inference accuracy and low communication latency simultaneously. | arxiv:2411.11539 |
virtual learning environments are a useful modality for engaging students in the classroom by affording them a sense of presence and immersion. the motivation of this project was to create an open - source augmented reality electrical circuit application for use in lower division engineering courses to teach students about electricity fundamentals. softwares that are readily available for use on virtual and augmented reality devices do not typically apply to all disciplines and do not necessarily have a pedagogical or accessibility focus. considering this lack of appropriate educational applications for the current virtual and augmented reality devices, a team of interdisciplinary students was assembled to create such software. with extensive usability studies, the application was designed for quick adoption and improve accessibility by providing multimodal access such as voice assistant, gray scaling for depth perception and daltonize the app. the software is available as part of vital laboratory, sonoma state university. | arxiv:1908.01963 |
we have developed a novel fabrication process for ultra - small, full - epitaxial nbn josephson junctions on a silicon ( si ) substrate. a full - epitaxial nbn / aln / nbn tri - layer was grown on a si ( 100 ) wafer with a ( 200 ) - oriented tin buffer layer. it was patterned into josephson junctions by an electron beam lithography ( ebl ) for junction definition followed by a reactive ion etch ( rie ). a chemical mechanical polishing ( cmp ) process and an additional rie by using chf $ _ 3 $ gas formed reliable electrical contacts between the junction counter electrodes and the wiring layer. all fabricated junctions, with a junction size down to 0. 27 $ \ mu $ m in diameter, showed excellent current - voltage characteristics with a clear gap structure and a small sub - gap leakage current. the dielectric layer of sio $ _ 2 $ that served as an insulator between base and counter electrodes was removed in a wet etching process using a buffered hf solution. we have confirmed that the quality of the junctions was maintained after the removal of the sio $ _ 2 $ dielectric layer. | arxiv:2004.00922 |
two charm - strange mesons, the $ d _ { s1 } ^ * ( 2710 ) $ and the $ d _ { sj } ^ * ( 2860 ) $, have recently been observed by several experiments. there has been speculation in the literature that the $ d _ { s1 } ^ * ( 2710 ) $ is the $ 2 ^ 3s _ 1 ( c \ bar { s } ) $ state and the $ d _ { sj } ^ * ( 2860 ) $ is the $ 1 ^ 3d _ 1 ( c \ bar { s } ) $ state. in this paper we explore this and other explanations in the context of the relativized quark model and the pseudoscalar emission decay model. we conclude that the $ d _ { s1 } ^ * ( 2710 ) $ is most likely the $ 1 ^ 3d _ 1 ( c \ bar { s } ) $ state and the $ d _ { sj } ^ * ( 2860 ) $ is most likely the $ 1 ^ 3d _ 3 ( c \ bar { s } ) $ state with the $ 1d _ 2 $ resonances also contributing to the observed signals and explaining the observed ratios of branching ratios to $ d ^ * k $ and $ dk $ final states. we point out that measuring the $ d _ { sj } ^ * ( 2860 ) $ spin can support or eliminate this explanation and that there are six excited $ d _ s $ states in this mass region ; the $ 2 ^ 3s _ 1 $, $ 2 ^ 1s _ 0 $, $ 1 ^ 3d _ 1 $, $ 1 ^ 3d _ 3 $ and two $ 1d _ 2 $ states. observing some of the missing states would help confirm the nature of the $ d _ { s1 } ^ * ( 2710 ) $ and the $ d _ { sj } ^ * ( 2860 ) $ states. | arxiv:1312.6181 |
semiclassical quantization rules and numerical calculations are applied to study polariton modes of materials whose permittivity tensor has principal values of opposite sign ( so - called hyperbolic materials ). the spectra of volume - and surface - confined polaritons are computed for spheroidal nanogranules of hexagonal boron nitride, a natural hyperbolic crystal. the field distribution created by polaritons excited by an external dipole source is predicted to exhibit ray - like patterns due to classical periodic orbits. near - field infrared imaging and purcell - factor measurements are suggested to test these predictions. | arxiv:1502.06524 |
the corresponding value of the function, f ( x ), is represented by a rectangle whose base is the interval corresponding to x and whose height is f ( x ) ( possibly negative, in which case the bar extends below the x - axis ). = = general properties = = this section describes general properties of functions, that are independent of specific properties of the domain and the codomain. = = = standard functions = = = there are a number of standard functions that occur frequently : for every set x, there is a unique function, called the empty function, or empty map, from the empty set to x. the graph of an empty function is the empty set. the existence of empty functions is needed both for the coherency of the theory and for avoiding exceptions concerning the empty set in many statements. under the usual set - theoretic definition of a function as an ordered triplet ( or equivalent ones ), there is exactly one empty function for each set, thus the empty function β
β x { \ displaystyle \ varnothing \ to x } is not equal to β
β y { \ displaystyle \ varnothing \ to y } if and only if x = y { \ displaystyle x \ neq y }, although their graphs are both the empty set. for every set x and every singleton set { s }, there is a unique function from x to { s }, which maps every element of x to s. this is a surjection ( see below ) unless x is the empty set. given a function f : x β y, { \ displaystyle f : x \ to y, } the canonical surjection of f onto its image f ( x ) = { f ( x ) x β x } { \ displaystyle f ( x ) = \ { f ( x ) \ mid x \ in x \ } } is the function from x to f ( x ) that maps x to f ( x ). for every subset a of a set x, the inclusion map of a into x is the injective ( see below ) function that maps every element of a to itself. the identity function on a set x, often denoted by idx, is the inclusion of x into itself. = = = function composition = = = given two functions f : x β y { \ displaystyle f : x \ to y } and g : y β z { \ displaystyle g : y \ to z } such that the domain of g is the cod | https://en.wikipedia.org/wiki/Function_(mathematics) |
monitoring downside risk and upside risk to the key macroeconomic indicators is critical for effective policymaking aimed at maintaining economic stability. in this paper i propose a parametric framework for modelling and forecasting macroeconomic risk based on stochastic volatility models with skew - normal and skew - t shocks featuring time varying skewness. exploiting a mixture stochastic representation of the skew - normal and skew - t random variables, in the paper i develop efficient posterior simulation samplers for bayesian estimation of both univariate and var models of this type. in an application, i use the models to predict downside risk to gdp growth in the us and i show that these models represent a competitive alternative to semi - parametric approaches such as quantile regression. finally, estimating a medium scale var on us data i show that time varying skewness is a relevant feature of macroeconomic and financial shocks. | arxiv:2306.09287 |
we prove two results concerning an ulam - type stability problem for homomorphisms between lattices. one of them involves estimates by quite general error functions ; the other deals with approximate ( join ) homomorphisms in terms of certain systems of lattice neighborhoods. as a corollary, we obtain a stability result for approximately monotone functions. | arxiv:1712.03513 |
following the recent report of superconductivity in the bilayer nickelate la $ _ { 3 } $ ni $ _ { 2 } $ o $ _ { 7 } $ under pressure, we present an analysis of the electronic and magnetic properties of la $ _ { 3 } $ ni $ _ { 2 } $ o $ _ { 7 } $ as a function of pressure using correlated density functional theory methods ( dft + $ u $ ). at the bare dft level, the electronic structure of the ambient and high - pressure phases of la $ _ { 3 } $ ni $ _ { 2 } $ o $ _ { 7 } $ are qualitatively similar. upon including local correlation effects within dft + $ u $ and allowing for magnetic ordering, we find a delicate interplay between pressure and electronic correlations. within the pressure - correlations phase space, we identify a region ( at $ u $ values consistent with constrained rpa ) characterized by a high spin to low spin transition with increasing pressure. in contrast to previous theoretical work that only highlights the crucial role of the ni - $ d _ { z ^ 2 } $ orbitals in this material, we find that the ni - $ d _ { x ^ { 2 } - y ^ { 2 } } $ orbitals are active upon pressure and drive this rich magnetic landscape. this picture is preserved in the presence of oxygen deficiencies. | arxiv:2309.17279 |
we extend the weak universality of kpz in [ hairer - quastel ] to weakly asymmetric interface models with general growth mechanisms beyond polynomials. a key new ingredient is a pointwise bound on correlations of trigonometric functions of gaussians in terms of their polynomial counterparts. this enables us to reduce the problem of a general nonlinearity with sufficient regularity to that of a polynomial. | arxiv:1802.08192 |
speech sound disorder ( ssd ) refers to the developmental disorder in which children encounter persistent difficulties in correctly pronouncing words. assessment of ssd has been relying largely on trained speech and language pathologists ( slps ). with the increasing demand for and long - lasting shortage of slps, automated assessment of speech disorder becomes a highly desirable approach to assisting clinical work. this paper describes a study on automatic detection of phonological errors in cantonese speech of kindergarten children, based on a newly collected large speech corpus. the proposed approach to speech error detection involves the use of a siamese recurrent autoencoder, which is trained to learn the similarity and discrepancy between phone segments in the embedding space. training of the model requires only speech data from typically developing ( td ) children. to distinguish disordered speech from typical one, cosine distance between the embeddings of the test segment and the reference segment is computed. different model architectures and training strategies are experimented. results on detecting the 6 most common consonant errors demonstrate satisfactory performance of the proposed model, with the average precision value from 0. 82 to 0. 93. | arxiv:2008.03193 |
the current need for atomic data to model stellar spectra obtained in various wavelength ranges is described. the level of completeness and accuracy of these data is discussed. | arxiv:1509.09165 |
the besiii collaboration claimed that a new $ a _ { 0 } ( 1817 ) $ resonance was found in the recent results of the $ d _ { s } ^ { + } \ rightarrow k _ { s } ^ { 0 } k ^ { + } \ pi ^ { 0 } $ decay. for this decay process, we perform a unitary amplitude to analyze the contributions of the states $ a _ { 0 } ( 980 ) ^ { + } $ and $ a _ { 0 } ( 1710 ) ^ { + } $ with the final state interactions. considering the cabibbo - favored external and internal $ w $ - emission mechanisms at the quark level, and the contributions of the resonances $ a _ { 0 } ( 980 ) ^ { + } $, $ a _ { 0 } ( 1710 ) ^ { + } $ in the $ s $ - wave and $ \ bar { k } ^ { * } ( 892 ) ^ { 0 } $, $ { k } ^ { * } ( 892 ) ^ { + } $ in the $ p $ - wave, the recent experimental data of the $ k _ { s } ^ { 0 } k ^ { + } $ invariant mass spectrum from the besiii collaboration can be described well. in our results, the states $ a _ { 0 } ( 980 ) $ and $ a _ { 0 } ( 1710 ) $ are dynamically generated from the final state interactions of $ k \ bar { k } $ and $ k ^ { * } \ bar { k } ^ { * } $, respectively, which support the molecular nature for them. moreover, some obtained branching fractions are in agreement with the experimental measurements. | arxiv:2306.06395 |
disconnectivity graphs are used to visualize the minima and the lowest energy barriers between the minima of complex systems. they give an easy and intuitive understanding of the underlying energy landscape and, as such, are excellent tools for understanding the complexity involved in finding low - lying or global minima of such systems. we have developed a classification scheme that categorizes highly - degenerate minima of spin glasses based on similarity and accessibility of the individual states. this classification allows us to condense the information pertained in different dales of the energy landscape to a single representation using color to distinguish its type and a bar chart to indicate the average size of the dales at their respective energy levels. we use this classification to visualize disconnectivity graphs of small representations of different tile - planted models of spin glasses. an analysis of the results shows that different models have distinctly different features in the total number of minima, the distribution of the minima with respect to the ground state, the barrier height and in the occurrence of the different types of minimum energy dales. | arxiv:2004.12431 |
the growing sluggishness of glass - forming liquids is thought to be accompanied by growing structural order. the nature of such order, however, remains hotly debated. a decade ago, point - to - set ( pts ) correlation lengths were proposed as measures of amorphous order in glass formers, but recent results raise doubts as to their generality. here, we extend the definition of pts correlations to agnostically capture any type of growing order in liquids, be it local or amorphous. this advance enables the formulation of a clear distinction between slowing down due to conventional critical ordering and that due to glassiness, and provides a unified framework to assess the relative importance of specific local order and generic amorphous order in glass formation. | arxiv:1511.03573 |
recently, it has been shown that while asperity models show correctly qualitative features of rough contact problems ( linearity in area - load, negative exponential dependence of load on separation which means also linearity of stiffness with load ), the exact value of the coefficients are not precise for the idealized case of gaussian distribution of heigths. this is due to the intrinsic simplifications, neglecting asperity coalescence and interaction effects. however, the issue of gaussianity has not been proved or experimentally verified in many cases, and here we show that, for example, assuming a weibull distribution of asperity heigths, the area - load linear coefficient is not much affected, while the relationships load - separation and therefore also stiffness - load do change largely, particularly when considering bounded distributions of asperity heigths. it is suggested that gaussianity of surfaces should be further tested in experiments, before applying the most sophisticated rough contact models based on the gaussian assumption. | arxiv:1602.07521 |
we consider paths of hamiltonian diffeomorphism preserving a given compact monotone lagrangian in a symplectic manifold that extend to an $ s ^ 1 $ - - hamiltonian action. we compute the leading term of the associated lagrangian seidel element. we show that such paths minimize the lagrangian hofer length. finally we apply these computations to lagrangian uniruledness and to give a nice presentation of the quantum cohomology of real lagrangians in fano symplectic toric manifolds. | arxiv:1307.8196 |
this paper explores the instruction fine - tuning technique for speech - to - semantic tasks by introducing a unified end - to - end ( e2e ) framework that generates target text conditioned on a task - related prompt for audio data. we pre - train the model using large and diverse data, where instruction - speech pairs are constructed via a text - to - speech ( tts ) system. extensive experiments demonstrate that our proposed model achieves state - of - the - art ( sota ) results on many benchmarks covering speech named entity recognition, speech sentiment analysis, speech question answering, and more, after fine - tuning. furthermore, the proposed model achieves competitive performance in zero - shot and few - shot scenarios. to facilitate future work on instruction fine - tuning for speech - to - semantic tasks, we release our instruction dataset and code. | arxiv:2309.02780 |
magnons - the quanta of spin waves - propagating in magnetic materials with wavelengths at the nanometer - scale and carrying information in the form of an angular momentum, can be used as data carriers in next - generation, nano - sized low - loss information processing systems. in this respect, artificial magnetic materials with properties periodically varied in space, known as magnonic crystals, are especially promising for controlling and manipulating the magnon currents. in this article, different approaches for the realization of static, reconfigurable, and dynamic magnonic crystals are presented along with a variety of novel wave phenomena discovered in these crystals. special attention is devoted to the utilization of magnonic crystals for processing of analog and digital information. | arxiv:1702.06701 |
we consider an autonomous system constructed as modification of the logistic differential equation with delay that generates successive trains of oscillations with phases evolving according to chaotic maps. the system contains two feedback loops characterized by two generally distinct retarding time parameters. in the case of their equality, chaotic dynamics is associated with the smale - williams attractor that corresponds to the double - expanding circle map for the phases of the carrier of the oscillatory trains. alternatively, at appropriately chosen two different delays attractor is close to torus with anosov dynamics on it as the phases are governed by the fibonacci map. in both cases the attractors manifest robustness ( absence of regularity windows under variation of parameters ) and presumably relate to the class of structurally stable hyperbolic attractors. | arxiv:1404.4221 |
we investigate the prevalence of sample repetition in a sequential monte carlo ( smc ) method recently introduced for political redistricting. | arxiv:2409.19017 |
digitalization and servitization are impacting many domains, including the mining industry. as the equipment becomes connected and technical infrastructure evolves, business models and risk management need to adapt. in this paper, we present a study on how changes in asset and risk distribution are evolving for the actors in a software ecosystem ( seco ) and system - of - systems ( sos ) around a mining operation. we have performed a survey to understand how service level agreements ( slas ) - - a common mechanism for managing risk - - are used in other domains. furthermore, we have performed a focus group study with companies. there is an overall trend in the mining industry to move the investment cost ( capex ) from the mining operator to the vendors. hence, the mining operator instead leases the equipment ( as operational expense, opex ) or even acquires a service. this change in business model impacts operation, as knowledge is moved from the mining operator to the suppliers. furthermore, as the infrastructure becomes more complex, this implies that the mining operator is more and more reliant on the suppliers for the operation and maintenance. as this change is still in an early stage, there is no formalized risk management, e. g. through slas, in place. rather, at present, the companies in the ecosystem rely more on trust and the incentives created by the promise of mutual future benefits of innovation activities. we believe there is a need to better understand how to manage risk in seco as it is established and evolves. at the same time, in a seco, the focus is on cooperation and innovation, the companies do not have incentives to address this unless there is an incident. therefore, industry need, we believe, help in systematically understanding risk and defining quality aspects such as reliability and performance in the new business environment. | arxiv:1907.08412 |
we present a self - consistent model of accretion flows which unifies four distinct spectral states observed in black hole x - ray binaries : quiescent, low, intermediate and high states. in the quiescent, low and intermediate states, the flow consists of an inner hot advection - dominated part extending from the black hole horizon to a transition radius and an outer thin disk. in the high state the thin disk is present at all radii. the model is essentially parameter - free and treats consistently the dynamics of the accretion flow, the thermal balance of the ions and electrons, and the radiation processes in the accreting gas. with increasing mass accretion rate, the model goes through a sequence of stages for which the computed spectra resemble very well observations of the four spectral states ; in particular, the low - to - high state transition observed in black hole binaries is naturally explained as resulting from a decrease in the transition radius. we also make a tentative proposal for the very high state, but this aspect of the model is less secure. we test the model against observations of the soft x - ray transient nova muscae during its 1991 outburst. the model reproduces the observed lightcurves and spectra surprisingly well, and makes a number of predictions which can be tested with future observations. | arxiv:astro-ph/9705237 |
in 2011 the dna seesaw gate motif was introduced. it is a powerful feed - forward dna nanodevice that can perform digital logic computations. the landmark of that work managed to evaluate moderately large boolean circuits by cascading multiple dna seesaw gates. although the design is robust in solution and scalable, it is designed for one time use and is not reusable. this prevents pursuing important applications such as feedback and sequential digital circuits. we present a novel design for dna nanodevices that can perform digital logic computations and are furthermore renewable. first, we modified the prior dna seesaw gate motif into a hairpin. we call the resulting motif a dna hairpin - seesaw gate. we show the feed - forward digital computation reaction imitates the seesaw gate motif. second, we added a reporting phase that provides increased scalability to our device. third, we designed input and fuel extracting hairpins that when added, initiate a renewing process. this results in a renewed functional gate, in its original configuration, which is able to make a new logical computation with new inputs. finally, we introduced a renewable two - input boolean logic or gate. after calculating the output of a certain input set, the circuit is restored and a new set of inputs is introduced to compute the new output. we provide experimental fluorescent data on three repeated rounds of executions of our hairpin gate motif and its restoration, indicating gradual loss of response. finally, we calculated rate constants of our experimental data by fitting it to a second order reaction model using maximum likelihood estimation method. | arxiv:1704.06371 |
we show that the neutrino mass, the dark matter and the dark energy can be explained in a unified framework, postulating a new invisible born - infeld field, which we name " non - linear dark photon ", undergoing a mev - scale dynamical transmutation and coupled to neutrinos. dark energy genesis is dynamically explained as a byproduct of the dark photon condensation, inducing the bare massless neutrinos to acquire an effective mass around the mev scale. it is fascinating to contemplate the channel induced by the non - linear dark photon leading to the pairing of the non - relativistic neutrinos, hence generating a cosmological superfluid state. as a consequence, the appearance of a light neutrino composite boson is predicted, providing a good cold dark matter candidate. in particular, if our model is enriched by an extra global lepton number $ u _ l ( 1 ) $ symmetry, then the neutrino pair can be identified with a composite majoron field with intriguing phenomenological implications for the neutrinoless - double - beta - decay ( $ 0 \ nu \ beta \ beta $ ). our model carries interesting phenomenological implications since dark energy, dark matter and the neutrino mass are time - varying dynamical variables, as a consequence of the non - linear born - infeld interaction terms. limits arising from planck + sne + bao collaborations data are also discussed. finally, our model allows for an inverse hierarchy of neutrino masses, with interesting implications for the juno experiment. | arxiv:2208.03591 |
we have measured the shubnikov - de haas oscillations in high - mobility si mos structures over a wide range of the carrier densities n > 0. 77x10 ^ { 11 } / cm ^ 2. this range includes the critical density n _ c of the metal - insulator transition ( 2d mit ) for two samples studied. the periodicity of oscillations clearly demonstrates that the electron states remain fourfold degenerate down to and at the 2d mit. both the effective spin susceptibility \ chi * and mass m * remain finite and show no signatures of divergency at the critical density for both samples studied. to test possible divergency of \ chi * ( n ) and m * ( n ) at even lower densities, we have analyzed the data on \ chi * ( n ) and m * ( n ) in terms of a critical dependence \ chi *, m * ~ ( n / n _ 0 - 1 ) ^ { - \ alpha }. our data suggest that \ chi * and m * may diverge at n _ 0 < 0. 5x10 ^ { 11 } / cm ^ 2 ( r _ s > 12 ), which is significantly smaller than n _ c. | arxiv:cond-mat/0110160 |
we discuss the internal structure of radially excited charmonium mesons based on the equal - time and coulomb gauge bethe - salpeter ( bs ) amplitudes, which are obtained in lattice qcd. our simulations are performed with a relativistic heavy - quark action for the charm quark on the 2 + 1 flavor pacs - cs gauge configurations at the lightest pion mass, $ m _ { \ pi } = 156 ( 7 ) $ mev. the variational method is applied to the study of optimal charmonium operator for ground and first excited states of $ s $ - wave charmonia. we successfully calculate the bs wave functions of $ \ eta _ c ( 2s ) $ and $ \ psi ( 2s ) $ states, as well as $ \ eta _ c ( 1s ) $ and $ j / \ psi $ states, and then estimate the root - mean - square radii of both the $ 1s $ and $ 2s $ charmonium states. we also examine whether a series of the bs wave functions from the ground state to excited states can be described by a single set of the spin - independent and spin - dependent interquark potentials with a unique quark mass. it is found that the quark kinetic mass and, both the central and spin - spin charmonium potentials, determined from the $ 2s $ wave functions, fairly agree with the ones from the $ 1s $ wave functions. this strongly supports the validity of the potential description for the charmonium system, at least, below open - charm threshold. | arxiv:1608.02340 |
berry phases strongly affect the properties of crystalline materials, giving rise to modifications of the semiclassical equations of motion that govern wave - packet dynamics. in non - hermitian systems, generalizations of the berry connection have been analyzed to characterize the topology of these systems. while the topological classification of non - hermitian systems is being developed, little attention has been paid to the impact of the new geometric phases on dynamics and transport. in this work, we derive the full set of semiclassical equations of motion for wave - packet dynamics in a system governed by a non - hermitian hamiltonian, including corrections induced by the berry connection. we show that non - hermiticity is manifested in anomalous weight rate and velocity terms that are present already in one - dimensional systems, in marked distinction from the hermitian case. we express the anomalous weight and velocity in terms of the berry connections defined in the space of left and right eigenstates and compare the analytical results with numerical lattice simulations. our work specifies the conditions for observing the anomalous contributions to the semiclassical dynamics and thereby paves the way to their experimental detection, which should be within immediate reach in currently available metamaterials. | arxiv:2004.13746 |
here, we correlate the nanoscale morphology and chemical composition of solid electrolyte interphases ( sei ) with the electrochemical property of graphite - based composite electrodes. using electrochemical strain microscopy ( esm ) and x - ray photoelectron spectroscopy ( xps ), changes of chemical composition and morphology ( li and f distribution ) in sei layers on the electrodes as a function of solid electrolyte contents are analyzed. as a result, we find a strong correlation between morphological variations on the electrode, li and f distribution in sei layer, and coulomb efficiency. this correlation determines the optimum composition of the composite electrode surface that can maximize the physical and chemical uniformity of the solid electrolyte on the electrode, which is a key parameter to increase electrochemical performance in solid - state batteries. | arxiv:2209.03651 |
future cosmic microwave background polarization experiments will search for evidence of primordial tensor modes at large angular scales, in the multipole range $ 4 \ leq \ ell \ leq 50. $ because in that range there is some mild evidence of departures from scale invariance in the power spectrum of primordial curvature perturbations, one may wonder about the possibility of similar deviations appearing in the primordial power spectrum of tensor modes. here we address this issue and analyze the possible presence of features in the tensor spectrum resulting from the dynamics of primordial fluctuations during inflation. we derive a general, model independent, relation linking features in the spectra of curvature and tensor perturbations. we conclude that even with large deviations from scale invariance in the curvature power spectrum, the tensor spectrum remains scale invariant for all observational purposes. | arxiv:1612.09253 |
cyber literacy merits serious research attention because it addresses a confluence of specialization and generalization ; cybersecurity is often conceived of as approachable only by a technological intelligentsia, yet its interdependent nature demands education for a broad population. therefore, educational tools should lead participants to discover technical knowledge in an accessible and attractive framework. in this paper, we present protection and deception ( p & g ), a novel two - player board game. p & g has three main contributions. first, it builds cyber literacy by giving participants " hands - on " experience with game pieces that have the capabilities of cyber - attacks such as worms, masquerading attacks / spoofs, replay attacks, and trojans. second, p & g teaches the important game - theoretic concepts of asymmetric information and resource allocation implicitly and non - obtrusively through its game play. finally, it strives for the important objective of security education for underrepresented minorities and people without explicit technical experience. we tested p & g at a community center in manhattan with middle - and high school students, and observed enjoyment and increased cyber literacy along with suggestions for improvement of the game. together with these results, our paper also presents images of the attractive board design and 3d printed game pieces, together with a monte - carlo analysis that we used to ensure a balanced gaming experience. | arxiv:1505.05570 |
we present a new method for finding principal null directions ( pnds ). because our method assumes as input the intrinsic metric and extrinsic curvature of a spacelike hypersurface, it should be particularly useful to numerical relativists. we illustrate our method by finding the pnds of the kastor - traschen spacetimes, which contain arbitrarily many $ q = m $ black holes in a de sitter back - ground. | arxiv:gr-qc/9406003 |
economics ( ) is a social science that studies the production, distribution, and consumption of goods and services. economics focuses on the behaviour and interactions of economic agents and how economies work. microeconomics analyses what is viewed as basic elements within economies, including individual agents and markets, their interactions, and the outcomes of interactions. individual agents may include, for example, households, firms, buyers, and sellers. macroeconomics analyses economies as systems where production, distribution, consumption, savings, and investment expenditure interact ; and the factors of production affecting them, such as : labour, capital, land, and enterprise, inflation, economic growth, and public policies that impact these elements. it also seeks to analyse and describe the global economy. other broad distinctions within economics include those between positive economics, describing " what is ", and normative economics, advocating " what ought to be " ; between economic theory and applied economics ; between rational and behavioural economics ; and between mainstream economics and heterodox economics. economic analysis can be applied throughout society, including business, finance, cybersecurity, health care, engineering and government. it is also applied to such diverse subjects as crime, education, the family, feminism, law, philosophy, politics, religion, social institutions, war, science, and the environment. = = definitions of economics = = the earlier term for the discipline was " political economy ", but since the late 19th century, it has commonly been called " economics ". the term is ultimately derived from ancient greek ΞΏΞΉΞΊΞΏΞ½ΞΏΞΌΞΉΞ± ( oikonomia ) which is a term for the " way ( nomos ) to run a household ( oikos ) ", or in other words the know - how of an ΞΏΞΉΞΊΞΏΞ½ΞΏΞΌΞΉΞΊΞΏΟ ( oikonomikos ), or " household or homestead manager ". derived terms such as " economy " can therefore often mean " frugal " or " thrifty ". by extension then, " political economy " was the way to manage a polis or state. there are a variety of modern definitions of economics ; some reflect evolving views of the subject or different views among economists. scottish philosopher adam smith ( 1776 ) defined what was then called political economy as " an inquiry into the nature and causes of the wealth of nations ", in particular as : a branch of the science of a statesman or legislator [ with the twofold objectives of providing ] a plentiful revenue or subsistence for the people... [ | https://en.wikipedia.org/wiki/Economics |
considerable efforts have been recently devoted to combining ultracold atoms and nanophotonic devices to obtain not only better scalability and figures of merit than in free - space implementations, but also new paradigms for atom - photon interactions. dielectric waveguides offer a promising platform for such integration because they enable tight transverse confinement of the propagating light, strong photon - atom coupling in single - pass configurations and potentially long - range atom - atom interactions mediated by the guided photons. however, the preparation of non - classical quantum states in such atom - waveguide interfaces has not yet been realized. here, by using arrays of individual caesium atoms trapped along an optical nanofibre, we observe a single collective atomic excitation coupled to a nanoscale waveguide. the stored collective entangled state can be efficiently read out with an external laser pulse, leading to on - demand emission of a single photon into the guided mode. we characterize the emitted single photon via the suppression of the two - photon component and confirm the single character of the atomic excitation, which can be retrieved with an efficiency of about 25 %. our results demonstrate a capability that is essential for the emerging field of waveguide quantum electrodynamics, with applications to quantum networking, quantum nonlinear optics and quantum many - body physics. | arxiv:1909.08641 |
we present a method which allows to deform extremal black hole solutions into non - extremal solutions, for a large class of supersymmetric and non - supersymmetric einstein - vector - scalar type theories. the deformation is shown to be largely independent of the details of the matter sector. while the line element is dressed with an additional harmonic function, the attractor equations for the scalars remain unmodified in suitable coordinates, and the values of the scalar fields on the outer and inner horizon are obtained from their fixed point values by making specific substitutions for the charges. for a subclass of models, which includes the five - dimensional stu - model, we find explicit solutions. | arxiv:1006.3439 |
we combine archival hst and new jwst imaging data, covering the ultraviolet to mid - infrared regime, to morphologically analyze the nuclear star cluster ( nsc ) of ngc 628, a grand - design spiral galaxy. the cluster is located in a 200 pc x 400 pc cavity, lacking both dust and gas. we find roughly constant values for the effective radius ( r _ eff ~ 5 pc ) and ellipticity ( { \ epsilon } ~ 0. 05 ), while the s \ ' ersic index ( n ) and position angle ( pa ) drop from n ~ 3 to ~ 2 and pa ~ 130 { \ deg } to 90 { \ deg }, respectively. in the mid - infrared, r _ eff ~ 12pc, { \ epsilon } ~ 0. 4, and n ~ 1 - 1. 5, with the same pa ~ 90 { \ deg }. the nsc has a stellar mass of log10 ( m _ nsc / m _ sun ) = 7. 06 + - 0. 31, as derived through b - v, confirmed when using multi - wavelength data, and in agreement with the literature value. fitting the spectral energy distribution, excluding the mid - infrared data, yields a main stellar population ' s age of ( 8 + - 3 ) gyr with a metallicity of z = 0. 012 + - 0. 006. there is no indication of any significant star formation over the last few gyr. whether gas and dust were dynamically kept out or evacuated from the central cavity remains unclear. the best - fit suggests an excess of flux in the mid - infrared bands, with further indications that the center of the mid - infrared structure is displaced with respect to the optical center of the nsc. we discuss five potential scenarios, none of them fully explaining both the observed photometry and structure. | arxiv:2211.13997 |
this paper presents a tri - branch neural fusion ( tnf ) approach designed for classifying multimodal medical images and tabular data. it also introduces two solutions to address the challenge of label inconsistency in multimodal classification. traditional methods in multi - modality medical data classification often rely on single - label approaches, typically merging features from two distinct input modalities. this becomes problematic when features are mutually exclusive or labels differ across modalities, leading to reduced accuracy. to overcome this, our tnf approach implements a tri - branch framework that manages three separate outputs : one for image modality, another for tabular modality, and a third hybrid output that fuses both image and tabular data. the final decision is made through an ensemble method that integrates likelihoods from all three branches. we validate the effectiveness of tnf through extensive experiments, which illustrate its superiority over traditional fusion and ensemble methods in various convolutional neural networks and transformer - based architectures across multiple datasets. | arxiv:2403.01802 |
the rise of internet connectivity has accelerated the spread of disinformation, threatening societal trust, decision - making, and national security. disinformation has evolved from simple text to complex multimodal forms combining images and text, challenging existing detection methods. traditional deep learning models struggle to capture the complexity of multimodal disinformation. inspired by advances in ai, this study explores using large language models ( llms ) for automated disinformation detection. the empirical study shows that ( 1 ) llms alone cannot reliably assess the truthfulness of claims ; ( 2 ) providing relevant evidence significantly improves their performance ; ( 3 ) however, llms cannot autonomously search for accurate evidence. to address this, we propose holmes, an end - to - end framework featuring a novel evidence retrieval method that assists llms in collecting high - quality evidence. our approach uses ( 1 ) llm - powered summarization to extract key information from open sources and ( 2 ) a new algorithm and metrics to evaluate evidence quality. holmes enables llms to verify claims and generate justifications effectively. experiments show holmes achieves 88. 3 % accuracy on two open - source datasets and 90. 2 % in real - time verification tasks. notably, our improved evidence retrieval boosts fact - checking accuracy by 30. 8 % over existing methods | arxiv:2505.03135 |
the family of generalized - harmonic gauge conditions, which is currently used in numerical relativity for its singularity - avoidant behavior, is analyzed by looking for pathologies of the corresponding spacetime foliation. the appearance of genuine shocks, arising from the crossing of characteristic lines, is completely discarded. runaway solutions, meaning that the lapse function can grow without bound at an accelerated rate, are instead predicted. black hole simulations are presented, showing spurious oscillations due to the well known slice stretching phenomenon. these oscillations are made to disappear by switching the numerical algorithm to a high - resolution shock - capturing one, of the kind currently used in computational fluid dynamics. even with these shock - capturing algorithms, runaway solutions are seen to appear and the resulting lapse blow - up is causing the simulations to crash. as a side result, a new method is proposed for obtaining regular initial data for black hole spacetimes, even inside the horizons. | arxiv:gr-qc/0410079 |
sequential assembly with geometric primitives has drawn attention in robotics and 3d vision since it yields a practical blueprint to construct a target shape. however, due to its combinatorial property, a greedy method falls short of generating a sequence of volumetric primitives. to alleviate this consequence induced by a huge number of feasible combinations, we propose a combinatorial 3d shape generation framework. the proposed framework reflects an important aspect of human generation processes in real life - - we often create a 3d shape by sequentially assembling unit primitives with geometric constraints. to find the desired combination regarding combination evaluations, we adopt bayesian optimization, which is able to exploit and explore efficiently the feasible regions constrained by the current primitive placements. an evaluation function conveys global structure guidance for an assembly process and stability in terms of gravity and external forces simultaneously. experimental results demonstrate that our method successfully generates combinatorial 3d shapes and simulates more realistic generation processes. we also introduce a new dataset for combinatorial 3d shape generation. all the codes are available at \ url { https : / / github. com / postech - cvlab / combinatorial - 3d - shape - generation }. | arxiv:2004.07414 |
in this paper, we present our solution to a multi - modal algorithmic reasoning task : smart - 101 challenge. different from the traditional visual question - answering datasets, this challenge evaluates the abstraction, deduction, and generalization abilities of neural networks in solving visuolinguistic puzzles designed specifically for children in the 6 - 8 age group. we employed a divide - and - conquer approach. at the data level, inspired by the challenge paper, we categorized the whole questions into eight types and utilized the llama - 2 - chat model to directly generate the type for each question in a zero - shot manner. additionally, we trained a yolov7 model on the icon45 dataset for object detection and combined it with the ocr method to recognize and locate objects and text within the images. at the model level, we utilized the blip - 2 model and added eight adapters to the image encoder vit - g to adaptively extract visual features for different question types. we fed the pre - constructed question templates as input and generated answers using the flan - t5 - xxl decoder. under the puzzle splits configuration, we achieved an accuracy score of 26. 5 on the validation set and 24. 30 on the private test set. | arxiv:2310.06440 |
we derive the coarse - graining ( cg ) equations of incompressible hall magnetohydrodynamics ( hmhd ) turbulence to investigate the { \ it local ( in space ) } energy cascade rate as a function of the filtering scale $ \ ell $. first, the cg equations are space averaged to obtain the analytical expression of the mean cascade rate. its application to 3 dimensional ( 3d ) simulations of ( weakly compressible ) hmhd shows a cascade rate consistent with the value of the mean dissipation rate in the simulations and with the classical estimates based on the " third - order " law. furthermore, we developed an anisotropic version of cg that allows us to study the magnitude of the cascade rate along different directions with respect to the mean magnetic field. its implementation on the numerical data with moderate background magnetic field shows a weaker cascade along the magnetic field than in the perpendicular plane, while an isotropic cascade is recovered in the absence of a background field. the strength of the cg approach is further revealed when considering the { \ it local - in - space } energy transfer, which is shown theoretically and numerically to match at a given position $ \ bm { x } $, when locally averaged over a neighboring region, the ( quasi - ) local dissipation. prospects of exploiting this new model to investigate local dissipation in spacecraft data are discussed. | arxiv:2203.01050 |
it has been established that quantum algorithms can solve several key cryptographic problems more efficiently than classical computers. as progress continues in the field of quantum computing it is important to understand the risks they pose to deployed cryptographic systems. here we focus on one of these risks - quantum key - recovery attacks against ideal ciphers. specifically, we seek to model the risk posed by an economically motivated quantum attacker who will choose to run a quantum key - recovery attack against an ideal cipher if the cost to recover the secret key is less than the value of the information at the time when the key - recovery attack is complete. in our analysis we introduce the concept of a quantum cipher circuit year to measure the cost of a quantum attack. this concept can be used to model the inherent tradeoff between the total time to run a quantum key recovery attack and the total work required to run said attack. our model incorporates the time value of the encrypted information to predict whether any time / work tradeoff results in a key - recovery attack with positive utility for the attacker. we make these predictions under various projections of advances in quantum computing. we use these predictions to make recommendations for the future use and deployment of symmetric key ciphers to secure information against these quantum key - recovery attacks. we argue that, even with optimistic predictions for advances in quantum computing, 128 bit keys ( as used in common cipher implementations like aes - 128 ) provide adequate security against quantum attacks in almost all use cases. | arxiv:2005.05911 |
the influence of poor solvent quality on fluid demixing of a model mixture of colloids and nonadsorbing polymers is investigated using density functional theory. the colloidal particles are modelled as hard spheres and the polymer coils as effective interpenetrating spheres that have hard interactions with the colloids. the solvent is modelled as a two - component mixture of a primary solvent, regarded as a background theta - solvent for the polymer, and a cosolvent of point particles that are excluded from both colloids and polymers. cosolvent exclusion favors overlap of polymers, mimicking the effect of a poor solvent by inducing an effective attraction between polymers. for this model, a geometry - based density functional theory is derived and applied to bulk fluid phase behavior. with increasing cosolvent concentration ( worsening solvent quality ), the predicted colloid - polymer binodal shifts to lower colloid concentrations, promoting demixing. for sufficiently poor solvent, a reentrant demixing transition is predicted at low colloid concentrations. | arxiv:cond-mat/0204330 |
volunteer military, the armed forces relies on market forces and careful recruiting to fill its ranks. it is thus, very important to understand factors that motivate enlistment and reenlistment. service members must have the mental and physical ability to meet the challenges of military service and adapt to the military ' s values and culture. studies show that enlistment motivation generally incorporates both self - interest ( pay ) and non - market values like adventure, patriotism, and comradeship. = = = veterans = = = the study of veterans or members of the military who leave and return to the society is one of the most important subfields of the military and society field of study. veterans and their issues represent a microcosm of the field. military recruits represent inputs that flow from the community into the armed forces, veterans are outputs that leave the military and reenter society changed by their time as soldiers, sailors, marines and airmen. both society and veteran face multiple layers of adaptation and adjustment upon their reentry. the definition of veteran is surprisingly fluid across countries. in the us, veteran ' s status is established after a service member has completed a minimum period of service. australia requires deployment to a combat zone. in the uk " everyone who has performed military service for at least one day and drawn a day ' s pay is termed a veteran. " the study of veterans focuses much attention on their, sometimes, uneasy transition back to civilian society. " veterans must navigate a complex cultural transition when moving between environments, " and they can expect positive and negative transition outcomes. finding a good job and reestablishing a fulfilling family life is high on their resettlement agenda. military life is often violent and dangerous. the trauma of combat often results in post - traumatic stress disorder as well as painful physical health challenges which often lead to homelessness, suicide, substance, and excessive alcohol use, and family dysfunction. society recognizes its responsibilities to veterans by offering programs and policies designed to redress these problems. veterans also exert an influence on society often through the political process. for example, how do veterans vote and establish party affiliation? during the 2004 presidential election veterans were basically bipartisan. veterans who fought in croatia ' s war of independence voted for the nationalist parties in greater numbers. = = = reserve forces = = = reserve forces are service members who serve the armed forces on a part - time basis. these men and women constitute a " reserve " force that countries rely on for their defense, disaster support, and some day - to - day operations etc | https://en.wikipedia.org/wiki/Military_science |
the low - energy effective action of string theory introduces corrections to the dilaton - graviton sector, resulting in deformed black holes beyond general relativity. we analyze extreme mass - ratio inspiral systems ( emris ), where a stellar - mass object spirals into a slowly rotating supermassive black hole including a distinct deviation parameter. this study examines the effects of this deformation on gravitational wave fluxes, orbital evolution, and phase dynamics, incorporating leading - order post - newtonian corrections. with one - year observations of emris, we employ the fisher information matrix method to evaluate the potential for detecting deviations from general relativity through space - based gravitational wave detectors that utilize time - delay interferometry to suppress laser noise. the constraint on modified black holes, $ \ delta \ alpha \ preceq 10 ^ { - 5 } $, is almost the same with and without the time - delay interferometry combination. this analysis enhances our understanding and underscores the crucial role of observations in advancing gravitational phenomena within string theory. | arxiv:2408.15064 |
a generalized power hypergraph $ \ mathcal { h } ^ k _ s $ is obtained from a base hypergraph $ \ mathcal { h } $ by means of some simple edge - expansion operations. kang, liu, qi and yuan [ 8 ] proved that the nonzero eigenvalues of $ \ mathcal { h } $ give rise to nonzero eigenvalues of $ \ mathcal { h } ^ k _ s $. in this paper we show that all nonzero eigenvalues of $ \ mathcal { h } ^ k _ s $ may be computed from the eigenvalues of its base hypergraph $ \ mathcal { h } $ and of its subgraphs. to prove this, we derive spectral results about edge - expansion operations that may be interesting on their own sake. | arxiv:1909.00234 |
we develop a correspondence between the theory of sequential algorithms and classical reasoning, via kreisel ' s no - counterexample interpretation. our framework views realizers of the no - counterexample interpretation as dynamic processes which interact with an oracle, and allows these processes to be modelled at any given level of abstraction. we discuss general constructions on algorithms which represent specific patterns which often appear in classical reasoning, and in particular, we develop a computational interpretation of the rule of dependent choice which is phrased purely on the level of algorithms, giving us a clearer insight into the computational meaning of proofs in classical analysis. | arxiv:1812.11003 |
nonadiabatic ring - polymer molecular dynamics employs the mapping approach to describe nonadiabatic effects within the ring - polymer ansatz. in this paper, it is generalized to allow for the nuclear and electronic degrees of freedom to be described by different numbers of ring - polymer beads. analysis of the resulting method shows that as the number of electronic mapping variables increases, certain problems associated with the approach are removed, such as the non - unique choice of the mapping hamiltonian and negative populations leading to inverted potential - energy surfaces. explicit integration over cyclic variables reduces the sign problem for the initial distribution in the general case. a new application for the simulation of vibronic spectra is described and promising results are presented for a model system. | arxiv:1609.00644 |
in recent years, mobile clients ' computing ability and storage capacity have greatly improved, efficiently dealing with some applications locally. federated learning is a promising distributed machine learning solution that uses local computing and local data to train the artificial intelligence ( ai ) model. combining local computing and federated learning can train a powerful ai model under the premise of ensuring local data privacy while making full use of mobile clients ' resources. however, the heterogeneity of local data, that is, non - independent and identical distribution ( non - iid ) and imbalance of local data size, may bring a bottleneck hindering the application of federated learning in mobile edge computing ( mec ) system. inspired by this, we propose a cluster - based clients selection method that can generate a federated virtual dataset that satisfies the global distribution to offset the impact of data heterogeneity and proved that the proposed scheme could converge to an approximate optimal solution. based on the clustering method, we propose an auction - based clients selection scheme within each cluster that fully considers the system ' s energy heterogeneity and gives the nash equilibrium solution of the proposed scheme for balance the energy consumption and improving the convergence rate. the simulation results show that our proposed selection methods and auction - based federated learning can achieve better performance with the convolutional neural network model ( cnn ) under different data distributions. | arxiv:2103.07150 |
a hitherto difficult and unsolved issue in plasma physics is how to give a general numerical solver for complicated plasma dispersion relation, although we have long known the general analytical forms. we transform the task to a full - matrix eigenvalue problem, which allows to numerically calculate all the dispersion relation solutions exactly free from convergence problem and give polarizations naturally for arbitrarily complicated multi - scale fluid plasma with arbitrary number of components. attempt to kinetic plasma via $ n $ - point pad \ ' e approximation of plasma dispersion function also shows good results. | arxiv:1304.5885 |
the electronic structure of a material fundamentally determines its underlying physical, and by extension, its functional properties. consequently, the ability to identify or generate materials with desired electronic properties would enable the design of tailored functional materials. traditional approaches relying on human intuition or exhaustive computational screening of known materials remain inefficient and resource - prohibitive for this task. here, we introduce dosmatgen, the first instance of a machine learning method which generates crystal structures that match a given desired electronic density of states. dosmatgen is an e ( 3 ) - equivariant joint diffusion framework, and utilizes classifier - free guidance to accurately condition the generated materials on the density of states. our experiments find this approach can successfully yield materials which are both stable and match closely with the desired density of states. furthermore, this method is highly flexible and allows for finely controlled generation which can target specific templates or even individual sites within a material. this method enables a more physics - driven approach to designing new materials for applications including catalysts, photovoltaics, and superconductors. | arxiv:2504.06249 |
interpretation of machine learning models has become one of the most important research topics due to the necessity of maintaining control and avoiding bias in these algorithms. since many machine learning algorithms are published every day, there is a need for novel model - agnostic interpretation approaches that could be used to interpret a great variety of algorithms. thus, one advantageous way to interpret machine learning models is to feed different input data to understand the changes in the prediction. using such an approach, practitioners can define relations among data patterns and a model ' s decision. this work proposes a model - agnostic interpretation approach that uses visualization of feature perturbations induced by the pso algorithm. we validate our approach on publicly available datasets, showing the capability to enhance the interpretation of different classifiers while yielding very stable results compared with state - of - the - art algorithms. | arxiv:2101.10502 |
we derive the effective hamiltonian of the nonrelativistic quantum electrodynamic up to $ m \ alpha ^ 8 $ by using scattering matching approach. at $ m \ alpha ^ 6 $ order, these results are coincide with pachucki ' s, which is obtained by applying foldy - wouthuysen transformation. and by using the nrqed hamiltonian, we derive the photon - exchange interaction in non - retarded approximation and the retardation correction up to $ m \ alpha ^ 8 $. the energy shift of the photon - exchange interaction is obtained by studying the pole of the total green function. | arxiv:1804.00417 |
understanding the relationships between geometric structures and semantic concepts is crucial for building accurate models of complex environments. in indoors, certain spatial constraints, such as the relative positioning of planes, remain consistent despite variations in layout. this paper explores how these invariant relationships can be captured in a graph slam framework by representing high - level concepts like rooms and walls, linking them to geometric elements like planes through an optimizable factor graph. several efforts have tackled this issue with add - hoc solutions for each concept generation and with manually - defined factors. this paper proposes a novel method for metric - semantic factor graph generation which includes defining a semantic scene graph, integrating geometric information, and learning the interconnecting factors, all based on graph neural networks ( gnns ). an edge classification network ( g - gnn ) sorts the edges between planes into same room, same wall or none types. the resulting relations are clustered, generating a room or wall for each cluster. a second family of networks ( f - gnn ) infers the geometrical origin of the new nodes. the definition of the factors employs the same f - gnn used for the metric attribute of the generated nodes. furthermore, share the new factor graph with the s - graphs + algorithm, extending its graph expressiveness and scene representation with the ultimate goal of improving the slam performance. the complexity of the environments is increased to n - plane rooms by training the networks on l - shaped rooms. the framework is evaluated in synthetic and simulated scenarios as no real datasets of the required complex layouts are available. | arxiv:2409.11972 |
in this paper, we study divisorial ideals of a hibi ring which is a toric ring arising from a partially ordered set. we especially characterize the special class of divisorial ideals called conic using the associated partially ordered set. using our description of conic divisorial ideals, we also construct a module giving a non - commutative crepant resolution ( = nccr ) of the segre product of polynomial rings. furthermore, applying the operation called mutation, we give other modules giving nccrs of it. | arxiv:1702.07058 |
we renormalize to three loops a version of the thirring model where the fermion fields not only lie in the fundamental representation of a non - abelian colour group su ( n _ c ) but also depend on the number of flavours, n _ f. the model is not multiplicatively renormalizable in dimensional regularization due to the generation of evanescent operators which emerge at each loop order. their effect in the construction of the true wave function, mass and coupling constant renormalization constants is handled by considering the projection technique to a new order. having constructed the msbar renormalization group functions we consider other massless independent renormalization schemes to ensure that the renormalization is consistent with the equivalence of the non - abelian thirring model with other models with a four - fermi interaction. one feature to emerge from the computation is the establishment of the fact that the su ( n _ f ) gross neveu model is not multiplicatively renormalizable in dimensional regularization. an evanescent operator arises first at three loops and we determine its associated renormalization constant explicitly. | arxiv:hep-th/9909046 |
we discuss the different signals, in gravitational and electromagnetic waves, emitted during the merger of two compact stars. we will focus in particular on the possible contraints that those signals can provide on the equation of state of dense matter. indeed, the stiffness of the equation of state and the particle composition of the merging compact stars, strongly affect e. g. the life time of the post - merger remnant and its gravitational wave signal, the emission of the short gamma - ray - burst, the amount of ejected mass and the related kilonova. the first detection of gravitational waves from the merger of two compact stars in august 2017, gw170817, and the subsequent detections of its electromagnetic counterparts, grb170817a and at2017gfo, is the first example of the era of " multi - messenger astronomy " : we discuss what we have learned from this detection on the equation of state of compact stars and we provide a tentative interpretation of this event, within the two families scenario, as due to the merger of a hadronic star with a quark star. | arxiv:1802.02495 |
study of the production of pairs of top quarks in association with a higgs boson is one of the primary goals of the large hadron collider over the next decade, as measurements of this process may help us to understand whether the uniquely large mass of the top quark plays a special role in electroweak symmetry breaking. higgs bosons decay predominantly to \ bbbar, yielding signatures for the signal that are similar to $ t \ bar { t } $ + jets with heavy flavor. though particularly challenging to study due to the similar kinematics between signal and background events, such final states ( $ t \ bar { t } b \ bar { b } $ ) are an important channel for studying the top quark yukawa coupling. this paper presents a systematic study of machine learning ( ml ) methods for detecting $ t \ bar { t } h $ in the $ h \ rightarrow b \ bar { b } $ decay channel. among the eight ml methods tested, we show that two models, extreme gradient boosted trees and neural network models, outperform alternative methods. we further study the effectiveness of ml algorithms by investigating the impact of feature set and data size, as well as the structure of the models. while extended feature set and larger training sets expectedly lead to improvement of performance, shallow models deliver comparable or better performance than their deeper counterparts. our study suggests that ensembles of trees and neurons, not necessarily deep, work effectively for the problem of $ t \ bar { t } h $ detection. | arxiv:1610.03088 |
after departure. when a button is pressed the control transmits a coded fsk radio signal to a receiver in the opener, raising or lowering the door. modern openers use 310, 315 or 390 mhz. to prevent a thief using a replay attack, modern openers use a rolling code system. radio - controlled models β a popular hobby is playing with radio - controlled model boats, cars, airplanes, and helicopters ( quadcopters ) which are controlled by radio signals from a handheld console with a joystick. most recent transmitters use the 2. 4 ghz ism band with multiple control channels modulated with pwm, pcm or fsk. wireless doorbell β a residential doorbell that uses wireless technology to eliminate the need to run wires through the building walls. it consists of a doorbell button beside the door containing a small battery powered transmitter. when the doorbell is pressed it sends a signal to a receiver inside the house with a speaker that sounds chimes to indicate someone is at the door. they usually use the 2. 4 ghz ism band. the frequency channel used can usually be changed by the owner in case another nearby doorbell is using the same channel. = = = = scientific research = = = = radio astronomy is the scientific study of radio waves emitted by astronomical objects. radio astronomers use radio telescopes, large radio antennas and receivers, to receive and study the radio waves from astronomical radio sources. since astronomical radio sources are so far away, the radio waves from them are extremely weak, requiring extremely sensitive receivers, and radio telescopes are the most sensitive radio receivers in existence. they use large parabolic ( dish ) antennas up to 500 meters ( 2, 000 ft ) in diameter to collect enough radio wave energy to study. the rf front end electronics of the receiver is often cooled by liquid nitrogen to reduce thermal noise. multiple antennas are often linked together in arrays which function as a single antenna, to increase collecting power. in very long baseline interferometry ( vlbi ) radio telescopes on different continents are linked, which can achieve the resolution of an antenna thousands of miles in diameter. remote sensing β in radio, remote sensing is the reception of electromagnetic waves radiated by natural objects or the atmosphere for scientific research. all warm objects emit microwaves and the spectrum emitted can be used to determine temperature. microwave radiometers are used in meteorology and earth sciences to determine temperature of the atmosphere and earth surface, as well as chemical reactions in the atmosphere. = = = = jamming = = = = radio jamming is the deliberate | https://en.wikipedia.org/wiki/Radio |
cell neighbor exchanges play a critical role in regulating tissue fluidity during epithelial morphogenesis and repair. in vivo, these neighbor exchanges are often hindered by the formation of transiently stable four - fold vertices, which can develop into complex multicellular rosettes where five or more cell junctions meet. despite their importance, the mechanical origins of multicellular rosettes have remained elusive, and current cellular models lack the ability to explain their formation and maintenance. here we present a dynamic vertex model of epithelial tissues with strain - dependent tension remodeling and mechanical memory dissipation. we show that an increase in cell junction tension upon contraction and reduction in tension upon extension can stabilize higher - order vertices, temporarily stalling cell rearrangements. on the other hand, inducing mechanical memory dissipation via relaxation of junction strain and stress promotes the resolution of higher - order vertices, facilitating cell neighbor exchanges. we demonstrate that by tuning the rates of tension remodeling and mechanical memory dissipation, we can control topological transitions and tissue material properties, recapitulating complex cellular topologies seen in developing organisms. | arxiv:2211.05591 |
methods such as chain - of - thought prompting and self - consistency have pushed the frontier of language model reasoning performance with no additional training. to further improve performance, we propose a prompt ensembling method for large language models, which uses a small dataset to construct a set of few shot prompts that together comprise a ` ` boosted prompt ensemble ' '. the few shot examples for each prompt are chosen in a stepwise fashion to be ` ` hard ' ' examples on which the previous step ' s ensemble is uncertain. we show that this outperforms single - prompt output - space ensembles and bagged prompt - space ensembles on the gsm8k and aqua datasets, among others. we propose both train - time and test - time versions of boosted prompting that use different levels of available annotation and conduct a detailed empirical study of our algorithm. | arxiv:2304.05970 |
the solid - liquid interface free energy \ gamma sl is a key parameter controlling nucleation and growth during solidification and other phenomena. there are intrinsic difficulties in obtaining accurate experimental values, and the previous approaches to compute \ gamma sl with atomistic simulations are computationally demanding. we propose a new approach, which is to obtain \ gamma sl from a free energy map of the phase transition reconstructed by metadynamics. we apply this to the benchmark case of a lennard - jones potential and the results confirm the most reliable data obtained previously. we demonstrate several advantages of our new approach : it is simple to implement, robust and free of hysteresis problems, it allows a rigorous and unbiased estimate of the statistical uncertainty and it returns a good estimate of of the thermodynamic limit with system sizes of a just a few hundred atoms. it is therefore attractive for using with more realistic and specific models of interatomic forces. | arxiv:0911.2615 |
this paper develops a grey - box approach to small - signal stability analysis of complex power systems that facilitates root - cause tracing without requiring disclosure of the full details of the internal control structure of apparatus connected to the system. the grey - box enables participation analysis in impedance models, which is popular in power electronics and increasingly accepted in power systems for stability analysis. the impedance participation factor is proposed and defined in terms of the residue of the whole - system admittance matrix. it is proved that, the so defined impedance participation factor equals the sensitivity of the whole - system eigenvalue with respect to apparatus impedance. the classic state participation factor is related to the impedance participation factor via a chain - rule. based on the chain - rule, a three - layer grey - box approach, with three degrees of transparency, is proposed for root - cause tracing to different depths, i. e. apparatus, states, and parameters, according to the available information. the association of impedance participation factor with eigenvalue sensitivity points to the re - tuning that would stabilize the system. the impedance participation factor can be measured in the field or calculated from the black - box impedance spectra with little prior knowledge required. | arxiv:2102.04226 |
we make and generalize the observation that summing of probability amplitudes of a discrete - time quantum walk over partitions of the walking graph consistent with the step operator results in a unitary evolution on the reduced graph which is also a quantum walk. since the effective walking graph of the projected walk is not necessarily simpler than the original, this may bring new insights into the dynamics of some kinds of quantum walks using known results from thoroughly studied cases like euclidean lattices. we use abstract treatment of the walking space and walker displacements in aim for a generality of the presented statements. using this approach we also identify some pathological cases in which the projection mapping breaks down. for walks on lattices, the operation typically results in quantum walks with hyper - dimensional coin spaces. such walks can, conversely, be viewed as projections of walks on inaccessible, larger spaces, and their properties can be inferred from the parental walk. we show that this is is the case for a lazy quantum walk, a walk with large coherent jumps and a walk on a circle with a twisted boundary condition. we also discuss the relation of this theory to the time - multiplexing optical implementations of quantum walks. moreover, this manifestly irreversible operation can, in some cases and with a minor adjustment, be undone, and a quantum walk can be reconstructed from a set of its projections. | arxiv:2004.01332 |
we show that the thermodynamics of a system of strings at high energy densities under the ideal gas approximation has a formulation in terms of hamilton - jacobi theory. the two parameters of the system, which have dimensions of energy density and number density, respectively, define a family of hypersurfaces of co - dimension one, which can be described by the vanishing of a function f that plays the role of a hamiltonian. | arxiv:0807.3957 |
in this work, we establish different control design approaches for discrete - time systems, which build upon the notion of finite - step control lyapunov functions ( fs - clfs ). the design approaches are formulated as optimization problems and solved in a model predictive control ( mpc ) fashion. in particular, we establish contractive multi - step mpc with and without reoptimization and compare it to classic mpc. the idea behind these approaches is to use the fs - clf as running cost. these new design approaches are particularly relevant in situations where information exchange between plant and controller cannot be ensured at all time instants. an example shows the different behavior of the proposed controller design approaches. | arxiv:1908.09660 |
fault tolerant on - chip photonic quantum computation is enormously helped by ( a ) deterministic generation of the needed thousands to millions of photon qubits from ( b ) quantum emitters in designed spatially ordered arrays to enable networks for implementing many - qubit logic circuits. scaling up photonic quantum information processing systems has, however, been prevented by the lack of such quantum emitters until the demonstration of the platform of mesa - top single quantum dots ( mtsqds ) - - controlled shape, size, and volume single qd - - located in designed regular arrays. here we demonstrate 2 qubit cnot gate operation - - a universal gate necessary to enable quantum circuits of arbitrary complexity - - in polarization basis using photons emitted from individual mtsqds. a bell state fidelity of 0. 825 $ \ pm $ 0. 010 is achieved with two photon interference ( tpi ) visibility of 0. 947 $ \ pm $ 0. 0015 at 4k without purcell enhancement. the results make a strong case for developing mtsqd arrays for utility scale optical quantum information processing platforms. | arxiv:2411.04412 |
or x = 5, { \ displaystyle x = 5, } and false otherwise. there are several different terminologies for this. in mathematical logic, an equation is a binary predicate ( i. e. a logical statement, that can have free variables ) which satisfies certain properties. in computer science, an equation is defined as a boolean - valued expression, or relational operator, which returns 1 and 0 for true and false respectively. = = = identities = = = an identity is an equality that is true for all values of its variables in a given domain. an " equation " may sometimes mean an identity, but more often than not, it specifies a subset of the variable space to be the subset where the equation is true. an example is ( x + 1 ) ( x + 1 ) = x 2 + 2 x + 1, { \ displaystyle \ left ( x + 1 \ right ) \ left ( x + 1 \ right ) = x ^ { 2 } + 2x + 1, } which is true for each real number x. { \ displaystyle x. } there is no standard notation that distinguishes an equation from an identity, or other use of the equality relation : one has to guess an appropriate interpretation from the semantics of expressions and the context. sometimes, but not always, an identity is written with a triple bar : ( x + 1 ) ( x + 1 ) β‘ x 2 + 2 x + 1. { \ displaystyle \ left ( x + 1 \ right ) \ left ( x + 1 \ right ) \ equiv x ^ { 2 } + 2x + 1. } this notation was introduced by bernhard riemann in his 1857 elliptische funktionen lectures ( published in 1899 ). alternatively, identities may be viewed as an equality of functions, where instead of writing f ( a ) = g ( a ) for all a, { \ displaystyle f ( a ) = g ( a ) { \ text { for all } } a, } one may simply write f = g. { \ displaystyle f = g. } this is called the extensionality of functions. in this sense, the operation - application property refers to operators, operations on a function space ( functions mapping between functions ) like composition or the derivative, commonly used in operational calculus. an identity can contain an functions as " unknowns ", which can be solved for similarly to a regular equation, called a functional equation. a functional equation involving derivatives is called a differential equation | https://en.wikipedia.org/wiki/Equality_(mathematics) |
we compare dynamical heterogeneities in equilibrated supercooled liquids and in the nonequilibrium glassy state within the framework of the random first order transition theory. fluctuating mobility generation and transport in the glass are treated by numerically solving stochastic continuum equations for mobility and fictive temperature fields that arise from an extended mode coupling theory containing activated events. fluctuating spatiotemporal structures in aging and rejuvenating glasses lead to dynamical heterogeneity in glasses with characteristics distinct from those found in the equilibrium supercooled liquid. the non - gaussian distribution of activation free energies, the stretching exponent $ \ beta $, and the growth of characteristic lengths are studied along with the four - point correlation function. asymmetric thermodynamic responses upon heating and cooling are predicted to be the results of the heterogeneity and the out - of - equilibrium behavior of glasses below $ t _ g $. numerical results agree with experimental calorimetry. we numerically confirm the prediction of lubchenko and wolynes in the glass that the dynamical heterogeneity can lead to noticeably bimodal distributions of local fictive temperatures which explains in a unified way recent experimental observations that have been interpreted as coming from two distinct equilibration mechanisms in glasses. | arxiv:1401.4485 |
the investigation reported in this document focuses on identifying systems with symmetries using equivariant autoregressive reservoir computers. general results in structured matrix approximation theory are presented, exploring a two - fold approach. firstly, a comprehensive examination of generic symmetry - preserving nonlinear time delay embedding is conducted. this involves analyzing time series data sampled from an equivariant system under study. secondly, sparse least - squares methods are applied to discern approximate representations of the output coupling matrices. these matrices play a pivotal role in determining the nonlinear autoregressive representation of an equivariant system. the structural characteristics of these matrices are dictated by the set of symmetries inherent in the system. the document outlines prototypical algorithms derived from the described techniques, offering insight into their practical applications. emphasis is placed on their effectiveness in the identification and predictive simulation of equivariant nonlinear systems, regardless of whether such systems exhibit chaotic behavior. | arxiv:2311.09511 |
with the aim of measuring the $ ^ { 235 } $ u ( n, f ) cross section at the n \ _ tof facility at cern over a wide neutron energy range, a detection system consisting of two fission detectors and three detectors for neutron flux determination was realized. the neutron flux detectors are recoil proton telescopes ( rpt ), based on scintillators and solid state detectors, conceived to detect recoil protons from the neutron - proton elastic scattering reaction. this system, along with a fission chamber and an array of parallel plate avalanche counters for fission event detection, was installed for the measurement at the n \ _ tof facility in 2018, at cern. an overview of the performances of two rpts - especially developed for this measurement - and of the parallel plate avalanche counters are described in this article. in particular, the characterization in terms of detection efficiency by monte carlo simulations and response to neutron beam, the study of the background, dead time correction and characterization of the samples, are reported. the results of the present investigation show that the performances of these detectors are suitable for accurate measurements of fission reaction cross sections in the range from 10 to 450 ~ mev. | arxiv:2211.12427 |
for many image clustering problems, replacing raw image data with features extracted by a pretrained convolutional neural network ( cnn ), leads to better clustering performance. however, the specific features extracted, and, by extension, the selected cnn architecture, can have a major impact on the clustering results. in practice, this crucial design choice is often decided arbitrarily due to the impossibility of using cross - validation with unsupervised learning problems. however, information contained in the different pretrained cnn architectures may be complementary, even when pretrained on the same data. to improve clustering performance, we rephrase the image clustering problem as a multi - view clustering ( mvc ) problem that considers multiple different pretrained feature extractors as different " views " of the same data. we then propose a multi - input neural network architecture that is trained end - to - end to solve the mvc problem effectively. our experimental results, conducted on three different natural image datasets, show that : 1. using multiple pretrained cnns jointly as feature extractors improves image clustering ; 2. using an end - to - end approach improves mvc ; and 3. combining both produces state - of - the - art results for the problem of image clustering. | arxiv:1807.07760 |
we compute the supersymmetric ( susy ) contributions to the observables in bs - - > k + k - and bs - - > k0 anti - k0 decays. the hadronic parameters in the standard - model ( sm ) amplitudes are obtained from the bd - - > k0 anti - k0 decay using a recent approach that combines flavor su ( 3 ) symmetry and a controlled input from qcd factorization. the latest experimental data for br ( bs - - > k + k - ) is in agreement with the sm prediction. we study how the branching ratios and the direct and mixing - induced cp asymmetries of both bs - - > kk decay modes are affected with the inclusion of susy, after imposing constraints from br ( b - - > xs gamma ), b - - > pi k and delta ms over the parameter space. while the branching ratios remain unaffected by susy, we identify the cp asymmetries of the bs - - > kk decays as the most promising observables to look for large deviations from the sm. | arxiv:hep-ph/0610109 |
n spectra yet. we make the spectrum available for future comparison with data from existing and next - generation ( e. g., elt and jwst ) spectrographs. | arxiv:1708.05747 |
we study two families of composite twisted ramond fields ( made by products of two operators ) in the $ \ cal { n } = ( 4, 4 ) $ supersymmetric d1 - d5 scft $ _ 2 $ deformed by a marginal modulus operator away from its $ ( t ^ 4 ) ^ n / s _ n $ free orbifold point. we construct the large - $ n $ contributions to the four - point functions with two composite operators and two deformation fields. these functions allow us to derive short - distance ope limits and to calculate the anomalous dimensions of the composite operators. we demonstrate that one can distinguish two sets of composite ramond states with twists $ m _ 1 $ and $ m _ 2 $ : protected states, for which $ m _ 1 + m _ 2 = n $, and " lifted " states for which $ m _ 1 + m _ 2 < n $. the latter require an appropriate renormalisation. we also derive the leading order corrections to their two - point functions, and to their three - point functions with the deformation operator. | arxiv:2006.16303 |
in this paper, we look at the question of when various ideals in the fourier algebra $ a ( g ) $ or its closures $ a _ m ( g ) $ and $ a _ { cb } ( g ) $ in, respectively, its multiplier and $ cb $ - multiplier algebra are arens regular. we show that in each case, if a non - zero ideal is arens regular, then the underlying group $ g $ must be discrete. in addition, we show that if an ideal $ i $ in $ a ( g ) $ has a bounded approximate identity, then it is arens regular if and only if it is finite - dimensional. | arxiv:2302.05699 |
we consider the spatial central force problem with a real analytic potential. we prove that for all analytic potentials, but the keplerian and the harmonic ones, the hamiltonian fulfills a nondegeneracy property needed for the applicability of nekhoroshev ' s theorem. we deduce stability of the actions over exponentially long times when the system is subject to arbitrary analytic perturbation. the case where the central system is put in interaction with a slow system is also studied and stability over exponentially long time is proved. | arxiv:1705.00576 |
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