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we investigate one - photon annihilation of the electron - positron pair in the field of a central, very heavy and positively charged atomic nucleus. the explicit formula for the annihilation rate of this process $ \ gamma ^ { ( b ) } _ { 1 \ gamma } $ is derived. our formula for this rate can directly be used to describe the actual one - photon annihilation in the ground ( bound ) states of all positronium hydrides hps, quasi - stable triplet states of the positron - helium atoms $ e ^ { + } [ $ he ( $ 2 ^ { 3 } s _ e $ ) ] ions and other systems.
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arxiv:2405.06720
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we introduce tiered sampling, a novel technique for approximate counting sparse motifs in massive graphs whose edges are observed in a stream. our technique requires only a single pass on the data and uses a memory of fixed size $ m $, which can be magnitudes smaller than the number of edges. our methods addresses the challenging task of counting sparse motifs - sub - graph patterns that have low probability to appear in a sample of $ m $ edges in the graph, which is the maximum amount of data available to the algorithms in each step. to obtain an unbiased and low variance estimate of the count we partition the available memory to tiers ( layers ) of reservoir samples. while the base layer is a standard reservoir sample of edges, other layers are reservoir samples of sub - structures of the desired motif. by storing more frequent sub - structures of the motif, we increase the probability of detecting an occurrence of the sparse motif we are counting, thus decreasing the variance and error of the estimate. we demonstrate the advantage of our method in the specific applications of counting sparse 4 and 5 - cliques in massive graphs. we present a complete analytical analysis and extensive experimental results using both synthetic and real - world data. our results demonstrate the advantage of our method in obtaining high - quality approximations for the number of 4 and 5 - cliques for large graphs using a very limited amount of memory, significantly outperforming the single edge sample approach for counting sparse motifs in large scale graphs.
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arxiv:1710.02108
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we present new gemini / gmos spectroscopic and archival imaging data of the interacting galaxy ngc 92, which is part of a compact group and displays an extended tidal tail. we have studied the physical properties of 20 star - forming complexes in this system. we found that the star - forming regions located in the tidal tail of ngc 92 have ages younger than 8 myr, which suggests that these objects were formed in situ. the spectroscopic data reveals that these regions have slightly sub - solar metallicities, suggesting that they were formed from pre - enriched material. using the oxygen abundances derived for each system, we found that the extended tidal tail of ngc 92 has a flat metallicity distribution. although this scenario is consistent with n - body simulations of interacting systems, where there is gas mixing triggered by the interaction, archival halpha fabry - perot data cubes of ngc 92 have not shown a velocity gradient along the tail of this galaxy, which under certain assumptions could be interpreted as a lack of gas flow in the tail. our results suggest that a fraction of the enriched gas that was originally located in the center of the galaxy was expelled into the tidal tail when the interacting process that formed the tail happened. however, we can not exclude the scenario in which the star formation in the tail has increased its original oxygen abundance.
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arxiv:1312.0812
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we propose a generalized peierls substitution method in conjunction with the tight - binding model to explore the magnetic quantization and quantum hall effect in twisted multilayer graphene under a magnetic field. the bloch - basis tight - binding hamiltonian is constructed for large twist angle while a simplified tight - binding model is employed for the magic angle. we investigate extensively the band structures, landau levels ( lls ), and quantum hall conductivity ( qhc ) of twisted bilayer graphene and twisted double bilayer graphene, as well as their dependence on the twist angle. comparison between these crucial properties of monolayer graphene, bernal bilayer graphene, and the twisted systems is carefully made to highlight the roles played by twisting. the unique selection rules of inter - ll transition, which is crucial for achieving a deep understanding of the step structures of qhc, are identified through the properties of ll wave functions. our theoretical model opens up an opportunity for comprehension of the interplay between an applied magnetic field and the twisting effect associated with multilayer graphene.
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arxiv:2112.10399
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we propose two possible new compounds, ba $ _ 2 $ cuo $ _ 2 $ fe $ _ 2 $ as $ _ 2 $ and k $ _ 2 $ cuo $ _ 2 $ fe $ _ 2 $ se $ _ 2 $, which hybridize the building blocks of two high temperature superconductors, cuprates and iron - based superconductors. these compounds consist of square cuo $ _ 2 $ layers and antifluorite - type fe $ _ 2 $ x $ _ 2 $ ( x = as, se ) layers separated by ba / k. the calculations of binding energies and phonon spectrums indicate that they are dynamically stable, which ensures that they may be experimentally synthesized. the fermi surfaces and electronic structures of the two compounds inherit the characteristics of both cuprates and iron - based superconductors. these compounds can be superconductors with intriguing physical properties to help to determine pairing mechanisms of high $ t _ c $ superconductivity.
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arxiv:1601.03220
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today, the near - earth space is facing a paradigm change as the number of new spacecraft is literally sky - rocketing. increasing numbers of small satellites threaten the sustainable use of space, as without removal, space debris will eventually make certain critical orbits unusable. a central factor affecting small spacecraft health and leading to debris is the radiation environment, which is unpredictable due to an incomplete understanding of the near - earth radiation environment itself and its variability driven by the solar wind and outer magnetosphere. this paper presents the foresail - 1 nanosatellite mission, having two scientific and one technological objectives. the first scientific objective is to measure the energy and flux of energetic particle loss to the atmosphere with a representative energy and pitch angle resolution over a wide range of magnetic local times. to pave the way to novel model - in situ data comparisons, we also show preliminary results on precipitating electron fluxes obtained with the new global hybrid - vlasov simulation vlasiator. the second scientific objective of the foresail - 1 mission is to measure energetic neutral atoms ( enas ) of solar origin. the solar ena flux has the potential to contribute importantly to the knowledge of solar eruption energy budget estimations. the technological objective is to demonstrate a satellite de - orbiting technology, and for the first time, make an orbit manoeuvre with a propellantless nanosatellite. foresail - 1 will demonstrate the potential for nanosatellites to make important scientific contributions as well as promote the sustainable utilisation of space by using a cost - efficient de - orbiting technology.
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arxiv:1905.09600
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we propose a class of multidimensional higher derivative theories of gravity without extra real degrees of freedom besides the graviton field. the propagator shows up the usual real graviton pole and extra complex conjugates poles that do not contribute to the absorptive part of the physical scattering amplitudes. indeed, they may consistently be excluded from the asymptotic observable states of the theory making use of the lee - wick and cutkoski, landshoff, olive and polkinghorne prescription for the construction of a unitary s - matrix. therefore, the spectrum consists on the graviton and short lived elementary unstable particles that we named " anti - gravitons " because of their repulsive contribution to the gravitational potential at short distance. however, another interpretation of the complex conjugate pairs is proposed based on the calmet ' s suggestion, i. e. they could be understood as black hole precursors long established in the classical theory. since the theory is cpt invariant, the complex conjugate of the micro black hole precursor has received as a white hole precursor consistently with the t ' hooft complementary principle. it is proved that the quantum theory is super - renormalizable in even dimension, i. e. only a finite number of divergent diagrams survive, and finite in odd dimension. furthermore, turning on a local potential of the riemann tensor we can make the theory finite in any dimension. the singularity - free newtonian gravitational potential is explicitly computed for a range of higher derivative theories. finally, we propose a new super - reneromalizable or finite lee - wick standard model of particle physics.
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arxiv:1602.02421
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thin coverings are a method of constructing graded - simple modules from simple ( ungraded ) modules. after a general discussion, we classify the thin coverings of ( quasifinite ) simple modules over associative algebras graded by finite abelian groups. the classification uses the representation theory of cyclotomic quantum tori. we close with an application to representations of multiloop lie algebras.
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arxiv:math/0605680
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based photometric follow - up and radial velocities. toi - 561 b is the first rocky world around a galactic thick - disk star confirmed with radial velocities and one of the best rocky planets for thermal emission studies.
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arxiv:2009.03071
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the dynamical aspect of accelerating cosmological model has been studied in this paper in the context of modified symmetric teleparallel gravity, the $ f ( q ) $ gravity. initially, we have derived the dynamical parameters for two well known forms of $ f ( q ) $ such as : ( i ) log - square - root form and ( ii ) exponential form. the equation of state ( eos ) parameter for the dark energy in the $ f ( q ) $ gravity in both the models emerges into a dynamical quantity. at present model - i shows the quintessence behavior and behave like the $ \ lambda $ cdm at the late time whereas model - ii shows phantom behaviour. further, the dynamical system analysis has been performed to determine the cosmological behaviour of the models along with its stability behaviour. for both the models the critical points are obtained and analysed the stability at each critical points with phase portraits. the evolutionary behaviour of density parameters for the matter - dominated, radiation - dominated, and dark energy phases are also shown for both the models.
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arxiv:2303.06427
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we report progress in the calibration of a method to determine cool dwarf star metallicities using molecular band strength indices. the molecular band index to metallicity relation can be calibrated using chemical abundances calculated from atomic line equivalent width measurements in high resolution spectra. building on previous work, we have measured fe and ti abundances in 32 additional m and k dwarf stars to extend the range of temperature and metallicity covered. a test of our analysis method using warm star - cool star binaries shows we can calculate reliable abundances for stars warmer than 3500 k. we have used abundance measurements for warmer binary or cluster companions to estimate abundances in 6 additional cool dwarfs. adding stars measured in our previous work and others from the literature provides 76 stars with fe abundance and cah2 and tio5 index measurements. the cah2 molecular index is directly correlated with temperature. tio5 depends on temperature and metallicity. metallicity can be estimated to within plus or minus 0. 3 dex within the bounds of our calibration, which extends from roughly [ fe / h ] = + 0. 05 to - 1. 0 with a limited extension to - 1. 5.
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arxiv:astro-ph/0510148
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recent advances in ai combine large language models ( llms ) with vision encoders that bring forward unprecedented technical capabilities to leverage for a wide range of healthcare applications. focusing on the domain of radiology, vision - language models ( vlms ) achieve good performance results for tasks such as generating radiology findings based on a patient ' s medical image, or answering visual questions ( e. g., ' where are the nodules in this chest x - ray? ' ). however, the clinical utility of potential applications of these capabilities is currently underexplored. we engaged in an iterative, multidisciplinary design process to envision clinically relevant vlm interactions, and co - designed four vlm use concepts : draft report generation, augmented report review, visual search and querying, and patient imaging history highlights. we studied these concepts with 13 radiologists and clinicians who assessed the vlm concepts as valuable, yet articulated many design considerations. reflecting on our findings, we discuss implications for integrating vlm capabilities in radiology, and for healthcare ai more generally.
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arxiv:2402.14252
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health economic evaluation studies are widely used in public health to assess health strategies in terms of their cost - effectiveness and inform public policies. we developed an r package for markov models implementing most of the modelling and reporting features described in reference textbooks and guidelines : deterministic and probabilistic sensitivity analysis, heterogeneity analysis, time dependency on state - time and model - time ( semi - markov and non - homogeneous markov models ), etc. in this paper we illustrate the features of heemod by building and analysing an example markov model. we then explain the design and the underlying implementation of the package.
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arxiv:1702.03252
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structural reliability methods aim at computing the probability of failure of systems with respect to some prescribed performance functions. in modern engineering such functions usually resort to running an expensive - to - evaluate computational model ( e. g. a finite element model ). in this respect simulation methods, which may require $ 10 ^ { 3 - 6 } $ runs cannot be used directly. surrogate models such as quadratic response surfaces, polynomial chaos expansions or kriging ( which are built from a limited number of runs of the original model ) are then introduced as a substitute of the original model to cope with the computational cost. in practice it is almost impossible to quantify the error made by this substitution though. in this paper we propose to use a kriging surrogate of the performance function as a means to build a quasi - optimal importance sampling density. the probability of failure is eventually obtained as the product of an augmented probability computed by substituting the meta - model for the original performance function and a correction term which ensures that there is no bias in the estimation even if the meta - model is not fully accurate. the approach is applied to analytical and finite element reliability problems and proves efficient up to 100 random variables.
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arxiv:1105.0562
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the full discretization of the semi - linear stochastic wave equation is considered. the discontinuous galerkin finite element method is used in space and analyzed in a semigroup framework, and an explicit stochastic position verlet scheme is used for the temporal approximation. we study the stability under a cfl condition and prove optimal strong convergence rates of the fully discrete scheme. numerical experiments illustrate our theoretical results. further, we analyze and bound the expected energy and numerically show excellent agreement with the energy of the exact solution.
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arxiv:2009.07710
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we consider the extremal values of the stationary distribution of sparse directed random graphs with given degree sequences and their relation to the extremal values of the in - degree sequence. the graphs are generated by the directed configuration model. under the assumption of bounded $ ( 2 + \ eta ) $ - moments on the in - degrees and of bounded out - degrees, we obtain tight comparisons between the maximum value of the stationary distribution and the maximum in - degree. under the further assumption that the order statistics of the in - degrees have a power - law behavior, we show that the extremal values of the stationary distribution also have a power - law behavior with the same index. in the same setting, we prove that these results extend to the pagerank scores of the random digraph, thus confirming a version of the so - called power - law hypothesis. along the way, we establish several facts about the model, including the mixing time cutoff and the characterization of the typical values of the stationary distribution, which were previously obtained under the assumption of bounded in - degrees.
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arxiv:2104.08389
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integrated plasmonics is advancing rapidly, enabling a wide range of functionalities to be incorporated onto a single chip. applications span information processing, computation, quantum sensing, and dark - matter detection. this progress has driven the development of integrated non - reciprocal devices, which are essential for preventing unwanted feedback that can degrade system performance. while non - reciprocal devices have been realized in edge magnetoplasmon materials via classical interference effects, their operation is often complicated by a dependence on input power. here, we demonstrate that topological circulators utilizing asymmetric coupling offer improved input power range, isolation, and insertion loss. in this configuration, non - reciprocal behavior arises from the coupling between a chiral edge magnetoplasmonic resonator and lc resonators, leading to non - hermitian dynamics. the coherent photon - plasmon interaction enables a circulator with up to 50 db of isolation across a broad range of excitation intensities. this is the first experimental demonstration showing that magnetic topological insulators can support the study of chiral plasmonic cavity quantum electrodynamics at radio frequencies, underscoring their potential to enable chip - scale quantum - classical interfaces in superconducting quantum information processing systems.
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arxiv:2505.07770
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we develop rigorous estimates and provably convergent approximations for the memory integral in the mori - zwanzig ( mz ) formulation. the new theory is built upon rigorous mathematical foundations and is presented for both state - space and probability density function space formulations of the mz equation. in particular, we derive errors bounds and sufficient convergence conditions for short - memory approximations, the $ t $ - model, and hierarchical ( finite - memory ) approximations. in addition, we derive computable upper bounds for the mz memory integral, which allow us to estimate ( a priori ) the contribution of the mz memory to the dynamics. numerical examples demonstrating convergence of the proposed algorithms are presented for linear and nonlinear dynamical systems evolving from random initial states.
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arxiv:1708.02235
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coulomb repulsion between two moving electrons loses its spherical symmetry due to relativistic effects. in presence of a uniform positive ion background this asymmetry uncovers an angular dependent attraction potential in the direction of motion. the quantum mechanical response to such an attraction potential is obtained through perturbation. it is shown that the transition amplitude between states with the symmetry of the attraction potential becomes negative and if the density of states is anisotropic, occurrence of a superconducting state becomes possible.
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arxiv:cond-mat/0501541
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we prove that the space $ m ( k ( x, y ) ) $ of $ \ mathbb r $ - places of the field $ k ( x, y ) $ of rational functions of two variables with coefficients in a totally archimedean field $ k $ has covering and integral dimensions $ \ dim m ( k ( x, y ) ) = \ dim _ \ iz m ( k ( x, y ) ) = 2 $ and the cohomological dimension $ \ dim _ g m ( k ( x, y ) ) = 1 $ for any abelian 2 - divisible coefficient group $ g $.
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arxiv:1110.5076
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using technique of supersymmetric quantum mechanics we present new cosmological quantum solution, in the regime for frw cosmological model using a barotropic perfect fluid as matter field.
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arxiv:gr-qc/0108031
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the task of reception of a copy of an arbitrary quantum state with use of a minimum quantity of quantum operations is considered.
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arxiv:quant-ph/0602035
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internet privacy is increasingly important on the modern internet. users are looking to control the trail of data that they leave behind on the systems that they interact with. multi - party relay ( mpr ) architectures lower the traditional barriers to adoption of privacy enhancing technologies on the internet. mprs are unique from legacy architectures in that they are able to offer privacy guarantees without paying significant performance penalties. apple ' s icloud private relay is a recently deployed mpr service, creating the potential for widespread consumer adoption of the architecture. however, many current internet - scale systems are designed based on assumptions that may no longer hold for users of privacy enhancing systems like private relay. there are inherent tensions between systems that rely on data about users - - estimated location of a user based on their ip address, for example - - and the trend towards a more private internet. this work studies a core function that is widely used to control network and application behavior, ip geolocation, in the context of icloud private relay usage. we study the location accuracy of popular ip geolocation services compared against the published location dataset that apple publicly releases to explicitly aid in geolocating pr users. we characterize geolocation service performance across a number of dimensions, including different countries, ip version, infrastructure provider, and time. our findings lead us to conclude that existing approaches to ip geolocation ( e. g., frequently updated databases ) perform inadequately for users of the mpr architecture. for example, we find median location errors > 1, 000 miles in some countries for ipv4 addresses using ip2location. our findings lead us to conclude that new, privacy - focused, techniques for inferring user location may be required as privacy becomes a default user expectation on the internet.
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arxiv:2307.04009
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this paper presents 6d - vit, a transformer - based instance representation learning network, which is suitable for highly accurate category - level object pose estimation on rgb - d images. specifically, a novel two - stream encoder - decoder framework is dedicated to exploring complex and powerful instance representations from rgb images, point clouds and categorical shape priors. for this purpose, the whole framework consists of two main branches, named pixelformer and pointformer. the pixelformer contains a pyramid transformer encoder with an all - mlp decoder to extract pixelwise appearance representations from rgb images, while the pointformer relies on a cascaded transformer encoder and an all - mlp decoder to acquire the pointwise geometric characteristics from point clouds. then, dense instance representations ( i. e., correspondence matrix, deformation field ) are obtained from a multi - source aggregation network with shape priors, appearance and geometric information as input. finally, the instance 6d pose is computed by leveraging the correspondence among dense representations, shape priors, and the instance point clouds. extensive experiments on both synthetic and real - world datasets demonstrate that the proposed 3d instance representation learning framework achieves state - of - the - art performance on both datasets, and significantly outperforms all existing methods.
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arxiv:2110.04792
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this paper presents a novel unifying framework of bilinear lstms that can represent and utilize the nonlinear interaction of the input features present in sequence datasets for achieving superior performance over a linear lstm and yet not incur more parameters to be learned. to realize this, our unifying framework allows the expressivity of the linear vs. bilinear terms to be balanced by correspondingly trading off between the hidden state vector size vs. approximation quality of the weight matrix in the bilinear term so as to optimize the performance of our bilinear lstm, while not incurring more parameters to be learned. we empirically evaluate the performance of our bilinear lstm in several language - based sequence learning tasks to demonstrate its general applicability.
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arxiv:1910.10294
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{ } ^ 3 \ pi $ state uv model to a future project. the so line list is available at exomol from www. exomol. com.
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arxiv:2312.09732
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here we compare critical properties of systems in the directed - percolation ( dp ) universality class with those of absorbing - state phase transitions occurring in the presence of a non - diffusive conserved field, i. e. transitions in the so - called manna or c - dp class. even if it is clearly established that these constitute two different universality classes, most of their universal features ( exponents, moment ratios, scaling functions,... ) are very similar, making it difficult to discriminate numerically between them. nevertheless, as illustrated here, the two classes behave in a rather different way upon introducing a physical boundary or wall. taking advantage of this, we propose a simple and fast method to discriminate between these two universality classes. this is particularly helpful in solving some existing discrepancies in self - organized critical systems as sandpiles.
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arxiv:cond-mat/0703209
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we study two designed and one natural zinc - finger peptide each with the cys2his2 ( cchh ) type of metal binding motif. in the approach we have developed, we describe the role of the protein and solvent outside the zn ( ii ) - cchh metal - residue cluster by a molecular field represented by generalized harmonic restraints. the strength of the field is adjusted to reproduce the binding energy distribution of the metal with the cluster obtained in a reference all - atom simulation with empirical potentials. the quadratic field allows us to investigate analytically the protein restraints on the binding site in terms of its eigenmodes. examining these eigenmodes suggests, consistent with experimental observations, the importance of the first histidine ( h ) in the cchh cluster in metal binding. further, the eigenvalues corresponding to these modes also indicate that the designed proteins form a tighter complex with the metal. we find that the bulk protein and solvent response tends to destabilize metal - binding, emphasizing that the favorable energetics of metal - residue interaction is necessary to drive folding in this system. the representation of the bulk protein and solvent response by a local field allows us to perform monte carlo simulations of the metal - residue cluster using quantum - chemical approaches, here using a semi - empirical hamiltonian. for configurations sampled from this simulation, we study the free energy of replacing zn ( ii ) with fe ( ii ), co ( ii ), and ni ( ii ) using density functional theory. the calculated selectivities are in fair agreement with experimental results.
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arxiv:1104.1337
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we present a secure approach for maintaining and reporting credit history records on the blockchain. our approach removes third - parties such as credit reporting agencies from the lending process and replaces them with smart contracts. this allows customers to interact directly with the lenders or banks while ensuring the integrity, unmalleability and privacy of their credit data. most importantly, each customer is given full control over complete or selective disclosure of her credit records, eliminating the risk of privacy violations or data breaches such as the one that happened to equifax in 2017. moreover, our approach provides strong guarantees for the lenders as well. a lender can check both correctness and completeness of the credit data disclosed to her. this is the first approach that is able to perform all real - world credit reporting tasks without a central authority or changing the financial mechanisms.
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arxiv:1805.09104
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social groups are fundamental building blocks of human societies. while our social interactions have always been constrained by geography, it has been impossible, due to practical difficulties, to evaluate the nature of this restriction on social group structure. we construct a social network of individuals whose most frequent geographical locations are also known. we also classify the individuals into groups according to a community detection algorithm. we study the variation of geographical span for social groups of varying sizes, and explore the relationship between topological positions and geographic positions of their members. we find that small social groups are geographically very tight, but become much more clumped when the group size exceeds about 30 members. also, we find no correlation between the topological positions and geographic positions of individuals within network communities. these results suggest that spreading processes face distinct structural and spatial constraints.
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arxiv:1011.4859
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we study the model of a composite - scalar made of a pair of scalar fields in 6 - 2 epsilon dimensions, using equivalence to the renormalizable three - elementary - scalar model under the " compositeness condition. " in this model, the composite - scalar field is induced by the quantum effects through the vacuum polarization of elementary - scalar fields with 2n species. we first investigate scale dependences of the coupling constant and masses, in the renormalizable three - elementary - scalar model, and derive the results for the composite model by imposing the compositeness condition. the model exhibits the formerly found general property that the coupling constant of the composite field is independent of the scale.
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arxiv:hep-th/0608079
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in this paper, we present several baselines for automatic speech recognition ( asr ) models for the two official written languages in norway : bokm { \ aa } l and nynorsk. we compare the performance of models of varying sizes and pre - training approaches on multiple norwegian speech datasets. additionally, we measure the performance of these models against previous state - of - the - art asr models, as well as on out - of - domain datasets. we improve the state of the art on the norwegian parliamentary speech corpus ( npsc ) from a word error rate ( wer ) of 17. 10 \ % to 7. 60 \ %, with models achieving 5. 81 \ % for bokm { \ aa } l and 11. 54 \ % for nynorsk. we also discuss the challenges and potential solutions for further improving asr models for norwegian.
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arxiv:2307.01672
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explicit reference governor ( erg ) is an add - on unit that provides constraint handling capability to pre - stabilized systems. the main idea behind erg is to manipulate the derivative of the applied reference in continuous time such that the satisfaction of state and input constraints is guaranteed at all times. however, erg should be practically implemented in discrete - time. this paper studies the discrete - time implementation of erg, and provides conditions under which the feasibility and convergence properties of the erg framework are maintained when the updates of the applied reference are performed in discrete time. the proposed approach is validated via extensive simulation and experimental studies.
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arxiv:2405.20549
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we consider the discrete eigenvalues of the operator $ h _ \ eps = - \ delta + v ( \ x ) + \ eps ^ 2q ( \ eps \ x ) $, where $ v ( \ x ) $ is periodic and $ q ( \ y ) $ is localized on $ \ r ^ d, \ \ d \ ge1 $. for $ \ eps > 0 $ and sufficiently small, discrete eigenvalues may bifurcate ( emerge ) from spectral band edges of the periodic schr \ " odinger operator, $ h _ 0 = - \ delta _ \ x + v ( \ x ) $, into spectral gaps. the nature of the bifurcation depends on the homogenized schr \ " odinger operator $ l _ { a, q } = - \ nabla _ \ y \ cdot a \ nabla _ \ y + \ q ( \ y ) $. here, $ a $ denotes the inverse effective mass matrix, associated with the spectral band edge, which is the site of the bifurcation.
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arxiv:1009.0922
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in this study, we introduced a new unit, named " protein token ", as a dynamic protein structural unit for protein - protein interactions. unlike the conventional structural units, protein token is not based on the sequential or spatial arrangement of residues, but comprises remote residues involved in cooperative conformational changes during protein interactions. application of protein token on ras gtpases revealed various tokens present in the superfamily. distinct token combinations were found in h - ras interacting with its various regulators and effectors, directing to a possible clue for the multiplexer property of ras superfamily. thus, this protein token theory may provide a new approach to study protein - protein interactions in broad applications.
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arxiv:1809.10458
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this paper presents the first framework for integrating procedural knowledge, or " know - how ", into the linked data cloud. know - how available on the web, such as step - by - step instructions, is largely unstructured and isolated from other sources of online knowledge. to overcome these limitations, we propose extending to procedural knowledge the benefits that linked data has already brought to representing, retrieving and reusing declarative knowledge. we describe a framework for representing generic know - how as linked data and for automatically acquiring this representation from existing resources on the web. this system also allows the automatic generation of links between different know - how resources, and between those resources and other online knowledge bases, such as dbpedia. we discuss the results of applying this framework to a real - world scenario and we show how it outperforms existing manual community - driven integration efforts.
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arxiv:1604.04506
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the development of fast and efficient quantum batteries is crucial for the prospects of quantum technologies. we show that both requirements are accomplished in the paradigmatic model of a harmonic oscillator strongly coupled to a highly non - markovian thermal reservoir. at short times, a dynamical blockade of the reservoir prevents the leakage of energy towards its degrees of freedom, promoting a significant accumulation of energy in the battery with high efficiency. the possibility of implementing these conditions in $ lc $ quantum circuits opens up new avenues for solid - state quantum batteries.
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arxiv:2407.16471
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we tackle the challenge of reliably determining the geo - location of nodes in decentralized networks, considering adversarial settings and without depending on any trusted landmarks. in particular, we consider active adversaries that control a subset of nodes, announce false locations and strategically manipulate measurements. to address this problem we propose, implement and evaluate verloc, a system that allows verifying the claimed geo - locations of network nodes in a fully decentralized manner. verloc securely schedules roundtrip time ( rtt ) measurements between randomly chosen pairs of nodes. trilateration is then applied to the set of measurements to verify claimed geo - locations. we evaluate verloc both with simulations and in the wild using a prototype implementation integrated in the nym network ( currently run by thousands of nodes ). we find that verloc can localize nodes in the wild with a median error of 60 km, and that in attack simulations it is capable of detecting and filtering out adversarial timing manipulations for network setups with up to 20 % malicious nodes.
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arxiv:2105.11928
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let $ g $ be a finite group of odd order, $ \ f $ a finite field of odd characteristic $ p $ and $ \ b $ a finite - - dimensional symplectic $ \ f g $ - module. we show that $ \ b $ is $ \ f g $ - hyperbolic, i. e., it contains a self - - perpendicular $ \ f g $ - submodule, iff it is $ \ f n $ - hyperbolic for every cyclic subgroup $ n $ of $ g $.
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arxiv:math/0412384
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we propose the qos - aware bs - selection and the corresponding resource - allocation schemes for downlink multi - user transmissions over the distributed multiple - input - multiple - output ( mimo ) links, where multiple location - independent base - stations ( bs ), controlled by a central server, cooperatively transmit data to multiple mobile users. our proposed schemes aim at minimizing the bs usages and reducing the interfering range of the distributed mimo transmissions, while satisfying diverse statistical delay - qos requirements for all users, which are characterized by the delay - bound violation probability and the effective capacity technique. specifically, we propose two bs - usage minimization frameworks to develop the qos - aware bs - selection schemes and the corresponding wireless resource - allocation algorithms across multiple mobile users. the first framework applies the joint block - diagonalization ( bd ) and probabilistic transmission ( pt ) to implement multiple access over multiple mobile users, while the second one employs time - division multiple access ( tdma ) approach to control multiple users ' links. we then derive the optimal bs - selection schemes for these two frameworks, respectively. in addition, we further discuss the pt - only based bs - selection scheme. also conducted is a set of simulation evaluations to comparatively study the average bs - usage and interfering range of our proposed schemes and to analyze the impact of qos constraints on the bs selections for distributed mimo transmissions.
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arxiv:1105.0035
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recent advancements in ai and edge computing have accelerated the development of machine - centric applications ( mcas ), such as smart surveillance systems. in these applications, video cameras and sensors offload inference tasks like license plate recognition and vehicle tracking to remote servers due to local computing and energy constraints. however, legacy network solutions, designed primarily for human - centric applications, struggle to reliably support these mcas, which demand heterogeneous and fluctuating qos ( due to diverse application inference tasks ), further challenged by dynamic wireless network conditions and limited spectrum resources. to tackle these challenges, we propose an application context - aware cross - layer optimization and resource design ( accord ) framework. this innovative framework anticipates the evolving demands of mcas in real time, quickly adapting to provide customized qos and optimal performance, even for the most dynamic and unpredictable mcas. this also leads to improved network resource management and spectrum utilization. accord operates as a closed feedback - loop system between the application client and network and consists of two key components : ( 1 ) building application context : it focuses on understanding the specific context of mca requirements. contextual factors include device capabilities, user behavior ( e. g., mobility speed ), and network channel conditions. ( 2 ) cross - layer network parameter configuration : utilizing a drl approach, this component leverages the contextual information to optimize network configuration parameters across various layers, including phy, mac, and rlc, as well as the application layer, to meet the desired qos requirement in real - time. extensive evaluation with the 3gpp - compliant matlab 5g toolbox demonstrates the practicality and effectiveness of our proposed accord framework.
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arxiv:2502.20320
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we study the derived tensor product of the representation rings of subgroups of a given compact lie group g. that is, given two such subgroups h _ 1 and h _ 2, we study the tensor product of the associated representation rings r ( h _ 1 ) and r ( h _ 2 ) over the representation ring rg, and prove a vanishing result for the associated higher tor - groups. this result can be viewed as a natural generalization of the theorem of steinberg that asserts that the representation rings of maximal rank subgroups of g are free over rg. it my also be viewed as an analogue of a result of singhof on the cohomology of classifying spaces. we include an immediate application to the complex k - theory of biquotient manifolds.
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arxiv:2305.02010
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to middle and high schools in the united states. programs include a high school engineering curriculum called pathway to engineering, a high school biomedical sciences program, and a middle school engineering and technology program called gateway to technology. pltw programs have been endorsed by president barack obama and united states secretary of education arne duncan as well as various state, national, and business leaders. = = = = stem education coalition = = = = the science, technology, engineering, and mathematics ( stem ) education coalition works to support stem programs for teachers and students at the u. s. department of education, the national science foundation, and other agencies that offer stem - related programs. activity of the stem coalition seems to have slowed since september 2008. = = = = scouting = = = = in 2012, the boy scouts of america began handing out awards, titled nova and supernova, for completing specific requirements appropriate to the scouts ' program level in each of the four main stem areas. the girl scouts of the usa has similarly incorporated stem into their program through the introduction of merit badges such as " naturalist " and " digital art ". sae is an international organization, and provider specializing in supporting education, award, and scholarship programs for stem matters, from pre - k to college degrees. it also promotes scientific and technological innovation. = = = = department of defense programs = = = = ecybermission is a free, web - based science, mathematics, and technology competition for students in grades six through nine sponsored by the u. s. army. each webinar is focused on a different step of the scientific method and is presented by an experienced ecybermission cyberguide. cyberguides are military and civilian volunteers with a strong background in stem and stem education, who can provide insight into science, technology, engineering, and mathematics to students and team advisers. starbase is an educational program, sponsored by the office of the assistant secretary of defense for reserve affairs. students interact with military personnel to explore careers and make connections with the " real world ". the program provides students with 20 – 25 hours of experience at the national guard, navy, marines, air force reserve, and air force bases across the nation. seaperch is an underwater robotics program that trains teachers to teach their students how to build an underwater remotely operated vehicle ( rov ) in an in - school or out - of - school setting. students build the rov from a kit composed of low - cost, easily accessible parts, following a curriculum that teaches basic engineering and science concepts
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https://en.wikipedia.org/wiki/Science,_technology,_engineering,_and_mathematics
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we present a formal model of checked c, a dialect of c that aims to enforce spatial memory safety. our model pays particular attention to the semantics of dynamically sized, potentially null - terminated arrays. we formalize this model in coq, and prove that any spatial memory safety errors can be blamed on portions of the program labeled unchecked ; this is a checked c feature that supports incremental porting and backward compatibility. while our model ' s operational semantics uses annotated ( " fat " ) pointers to enforce spatial safety, we show that such annotations can be safely erased : using plt redex we formalize an executable version of our model and a compilation procedure from it to an untyped c - like language, and use randomized testing to validate that generated code faithfully simulates the original. finally, we develop a custom random generator for well - typed and almost - well - typed terms in our redex model, and use it to search for inconsistencies between our model and the clang checked c implementation. we find these steps to be a useful way to co - develop a language ( checked c is still in development ) and a core model of it.
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arxiv:2201.13394
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we present a systematic study of the effect of the disorder in copper point contacts. we show that peaks in the conductance histogram of copper point contacts shift upon addition of nickel impurities. the shift increases initially linerarly with the nickel concentration, thus confirming that it is due to disorder in the nanowire, in accordance with predictions. in general, this shift is modelled as a resistance r _ s which is placed in series with the contact resistance r _ c. however, we obtain different r _ s values for the two peaks in the histogram, r _ s being larger for the peak at higher conductance.
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arxiv:cond-mat/0201078
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we theoretically investigate nonequilibrium spin fluctuations in a ferromagnet induced by a light pulse. using a lindblad equation consistent with the landau - lifshitz - gilbert equation, we compute the autocorrelation function of magnetization. our analysis reveals that this function comprises both thermal and nonequilibrium components. to examine the latter in detail, we introduce a fano factor similar to nonequilibrium current noise in electronic circuits. we demonstrate that this factor encapsulates insights into the transfer of spin units to the environment. our findings lay the groundwork for nonequilibrium spin noise spectroscopy, offering valuable insights into spin relaxation dynamics.
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arxiv:2405.10522
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this paper presents small - scale fading measurements for 28 ghz outdoor millimeter - wave ultrawideband channels using directional horn antennas at the transmitter and receiver. power delay profiles were measured at half - wavelength spatial increments over a local area ( 33 wavelengths ) on a linear track in two orthogonal receiver directions in a typical base - to - mobile scenario with fixed transmitter and receiver antenna beam pointing directions. the voltage path amplitudes are shown to follow a rician distribution, with k - factor ranging from 9 - 15 db and 5 - 8 db in line of sight ( los ) and non - line of sight ( nlos ) for a vertical - to - vertical co - polarized antenna scenario, respectively, and from 3 - 7 db in both los and nlos vertical - to - horizontal cross - polarized antenna scenario. the average spatial autocorrelation functions of individual multipath components reveal that signal amplitudes reach a correlation of 0 after 2 and 5 wavelengths in los and nlos co - polarized v - v antenna scenarios. the models provided are useful for recreating path gain statistics of millimeter - wave wideband channel impulse responses over local areas, for the study of multi - element antenna simulations and channel estimation algorithms.
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arxiv:1511.06938
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virtualization has become widespread across all computing environments, from edge devices to cloud systems. its main advantages are resource management through abstraction and improved isolation of platform resources and processes. however, there are still some important tradeoffs as it requires significant support from the existing hardware infrastructure and negatively impacts performance. additionally, the current approaches to resource virtualization are inflexible, using a model that doesn ' t allow for dynamic adjustments during operation. this research introduces light virtualization ( lightv ), a new virtualization method for commercial platforms. lightv uses programmable hardware to direct cache coherence traffic, enabling precise and seamless control over which resources are virtualized. the paper explains the core principles of lightv, explores its capabilities, and shares initial findings from a basic proof - of - concept module tested on commercial hardware.
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arxiv:2502.15738
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we consider the inverse galois problem over function fields of positive characteristic p, for example, the inverse galois problem over the projective line. we describe a method to construct certain galois covers of the projective line and other curves, which are ordinary in the sense that their jacobian has maximal p - torsion. we do this by constructing galois covers of ordinary semi - stable curves, and then deforming them into smooth galois covers.
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arxiv:1704.07608
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how can we better organize code in computational notebooks? notebooks have become a popular tool among data scientists, as they seamlessly weave text and code together, supporting users to rapidly iterate and document code experiments. however, it is often challenging to organize code in notebooks, partially because there is a mismatch between the linear presentation of code and the non - linear process of exploratory data analysis. we present stickyland, a notebook extension for empowering users to freely organize their code in non - linear ways. with sticky cells that are always shown on the screen, users can quickly access their notes, instantly observe experiment results, and easily build interactive dashboards that support complex visual analytics. case studies highlight how our tool can enhance notebook users ' s productivity and identify opportunities for future notebook designs. stickyland is available at https : / / github. com / xiaohk / stickyland.
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arxiv:2202.11086
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we consider the \ emph { budgeted } version of the classical \ emph { connected dominating set } problem ( bcds ). given a graph $ g $ and a budget $ k $, we seek a connected subset of at most $ k $ vertices maximizing the number of dominated vertices in $ g $. we improve over the previous $ ( 1 - 1 / e ) / 13 $ approximation in [ khuller, purohit, and sarpatwar, \ \ emph { soda 2014 } ] by introducing a new method for performing tree decompositions in the analysis of the last part of the algorithm. this new approach provides a $ ( 1 - 1 / e ) / 12 $ approximation guarantee. by generalizing the analysis of the first part of the algorithm, we are able to modify it appropriately and obtain a further improvement to $ ( 1 - e ^ { - 7 / 8 } ) / 11 $. on the other hand, we prove a $ ( 1 - 1 / e + \ epsilon ) $ inapproximability bound, for any $ \ epsilon > 0 $. we also examine the \ emph { edge - vertex domination } variant, where an edge dominates its endpoints and all vertices neighboring them. in \ emph { budgeted edge - vertex domination } ( bevd ), we are given a graph $ g $, and a budget $ k $, and we seek a, not necessarily connected, subset of $ k $ edges such that the number of dominated vertices in $ g $ is maximized. we prove there exists a $ ( 1 - 1 / e ) $ - approximation algorithm. also, for any $ \ epsilon > 0 $, we present a $ ( 1 - 1 / e + \ epsilon ) $ - inapproximability result by a gap - preserving reduction from the \ emph { maximum coverage } problem. finally, we examine the " dual " \ emph { partial edge - vertex domination } ( pevd ) problem, where a graph $ g $ and a quota $ n ' $ are given. the goal is to select a minimum - size set of edges to dominate at least $ n ' $ vertices in $ g $. in this case, we present a $ h ( n ' ) $ - approximation algorithm by a reduction to the \ emph { partial cover } problem.
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arxiv:1907.06576
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accurate representation of the multiscale features in spatiotemporal physical systems using vision transformer ( vit ) architectures requires extremely long, computationally prohibitive token sequences. to address this issue, we propose two adaptive tokenization schemes that dynamically adjust patch sizes based on local features : one ensures convergent behavior to uniform patch refinement, while the other offers better computational efficiency. moreover, we present a set of spatiotemporal attention schemes, where the temporal or axial spatial dimensions are decoupled, and evaluate their computational and data efficiencies. we assess the performance of the proposed multiscale adaptive model, matey, in a sequence of experiments. the results show that adaptive tokenization schemes achieve improved accuracy without significantly increasing the length of the token sequence. compared to a full spatiotemporal attention scheme or a scheme that decouples only the temporal dimension, we find that fully decoupled axial attention is less efficient and expressive, requiring more training time and model weights to achieve the same accuracy. finally, we demonstrate in two fine - tuning tasks featuring different physics that models pretrained on pdebench data outperform the ones trained from scratch, especially in the low data regime with frozen attention.
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arxiv:2412.20601
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the dependence of the magnetic fluctuations and the spin coherence time $ t _ 2 ^ { \ rm hyp } $ of the lowest stark states $ ^ 4i _ { 15 / 2 } \ ( z _ 1 ) $ in $ ^ { 167 } $ er $ ^ { 3 + } $ : y $ _ 2 $ sio $ _ 5 $ under zero magnetic field on er concentration is numerically investigated in the range of 10 to 10 $ ^ 6 $ parts per million ( ppm ). the magnetic fluctuations surrounding the target er electron generated by the dipole - dipole interaction due to two components, y ions in host crystal and doped er ions, are calculated by monte - carlo method. the former magnetic fluctuation is constant, while the latter depends on er concentration. due to these two components, the er - concentration dependence of $ t _ 2 ^ { \ rm hyp } $ at the zero first - order zeeman ( zefoz ) points saturates for crystals with er concentration below 10 ppm and no extension of the $ t _ 2 ^ { \ rm hyp } $ is expected without an external magnetic field. under a magnetic field, the longest $ t _ 2 ^ { \ rm hyp } $ at a particular zefoz point is expected to be over 150 s ( 90 s ) for site 1 ( site 2 ), which is $ \ sim 10 ^ 5 $ times longer than that at zero field for 10 - ppm $ ^ { 167 } $ er $ ^ { 3 + } $ : y $ _ 2 $ sio $ _ 5 $. interestingly, the zefoz points under a magnetic field appear almost along the one direction for site 1 and almost in one plane for site 2 in optical frame $ ( d _ 1, d _ 2, b ) $. the experiment favors this trend in the position of the zefoz points which can be explained on the basis of the anisotropy of the effective spin hamiltonian parameters. finally, the tolerance of the zefoz point at each site with the longest $ t _ 2 ^ { \ rm hyp } $ against the errors in the applied magnetic field vector is evaluated numerically.
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arxiv:2412.10126
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we explore the celestial holography proposal for non - trivial asymptotically flat backgrounds including the coulomb field of a static and spinning point charge, their gravitational counterparts described by the schwarzschild and kerr metrics, as well as the aichelburg - sexl shockwave and spinning shockwave geometries and their electromagnetic cousins. we compute celestial two - point amplitudes on these kerr - schild type backgrounds which have the desirable feature, due to the presence of an external source, that they are non - vanishing for general operator positions and are not constrained by the kinematic delta functions of flat space celestial cft correlators. of particular interest is the case of shockwave backgrounds where the two - point scattering amplitude of massless scalars can be interpreted as a standard cft three - point correlator between two massless asymptotic states and a conformal primary shockwave operator. we furthermore show that the boundary on - shell action for general backgrounds becomes the generating functional for tree - level correlation functions in celestial cft. finally, we derive ( conformal ) faddeev - kulish dressings for particle - like backgrounds which remove all infrared divergent terms in the two - point functions to all orders in perturbation theory.
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arxiv:2207.13719
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we construct two pencils of bielliptic curves of genus three and genus five. the first pencil is associated with a general abelian surface with a polarization of type $ ( 1, 2 ) $. the second pencil is related to the first by an unramified double cover, the prym variety of which is canonically isomorphic to the jacobian of a very general curve of genus two. our results are obtained by analyzing suitable elliptic fibrations on the associated kummer surfaces and rational double covers among them.
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arxiv:2005.04839
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{ \ em riemannian cubics } are curves in a manifold $ m $ that satisfy a variational condition appropriate for interpolation problems. when $ m $ is the rotation group so ( 3 ), riemannian cubics are track - summands of { \ em riemannian cubic splines }, used for motion planning of rigid bodies. partial integrability results are known for riemannian cubics, and the asymptotics of riemannian cubics in so ( 3 ) are reasonably well understood. the mathematical properties and medium - term behaviour of riemannian cubics in so ( 3 ) are known to be be extremely rich, but there are numerical methods for calculating riemannian cubic splines in practice. what is missing is an understanding of the short - term behaviour of riemannian cubics, and it is this that is important for applications. the present paper fills this gap by deriving approximations to nearly geodesic riemannian cubics in terms of elementary functions. the high quality of these approximations depends on mathematical results that are specific to riemannian cubics.
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arxiv:1104.2397
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solomonoff unified occam ' s razor and epicurus ' principle of multiple explanations to one elegant, formal, universal theory of inductive inference, which initiated the field of algorithmic information theory. his central result is that the posterior of his universal semimeasure m converges rapidly to the true sequence generating posterior mu, if the latter is computable. hence, m is eligible as a universal predictor in case of unknown mu. we investigate the existence and convergence of computable universal ( semi ) measures for a hierarchy of computability classes : finitely computable, estimable, enumerable, and approximable. for instance, m is known to be enumerable, but not finitely computable, and to dominate all enumerable semimeasures. we define seven classes of ( semi ) measures based on these four computability concepts. each class may or may not contain a ( semi ) measure which dominates all elements of another class. the analysis of these 49 cases can be reduced to four basic cases, two of them being new. the results hold for discrete and continuous semimeasures. we also investigate more closely the types of convergence, possibly implied by universality : in difference and in ratio, with probability 1, in mean sum, and for martin - loef random sequences. we introduce a generalized concept of randomness for individual sequences and use it to exhibit difficulties regarding these issues.
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arxiv:cs/0305052
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the signing key protection of certificate authorities ( cas ) remains a critical challenge in pki. traditional approaches struggle to eliminate the risk of key exposure due to those ( un ) intentional human errors. this long - standing dilemma motivates us to propose armored core, a novel pki security extension using the trusted binding of physically unclonable function ( puf ) for cas. pufs leverage manufacturing variations to generate unique and random responses. combining with xor and hash, they can make key exposure impossible for cas through keyless certificate issuance. in armored core, we design a set of puf - based x. 509v3 certificate functions for cas to generate physically trusted " signatures " without using a digital key. moreover, we introduce a novel puf transparency mechanism to effectively monitor the puf operations in cas. we integrate armored core into real - world pki systems including let ' s encrypt pebble and certbot. we also provide a puf - embedded hardware prototype. the evaluation results show that armored core can achieve keyless certificate issuance while improving the computation performance by 4. 9 % ~ 73. 7 %. it only incurs small communication and storage overhead ( < 4 % ).
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arxiv:2404.15582
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the rationalizability concept was introduced in \ cite { ber84 } and \ cite { pea84 } to assess what can be inferred by rational players in a non - cooperative game in the presence of common knowledge. however, this notion can be defined in a number of ways that differ in seemingly unimportant minor details. we shed light on these differences, explain their impact, and clarify for which games these definitions coincide. then we apply the same analysis to explain the differences and similarities between various ways the iterated elimination of strictly dominated strategies was defined in the literature. this allows us to clarify the results of \ cite { ds02 } and \ cite { cll05 } and improve upon them. we also consider the extension of these results to strict dominance by a mixed strategy. our approach is based on a general study of the operators on complete lattices. we allow transfinite iterations of the considered operators and clarify the need for them. the advantage of such a general approach is that a number of results, including order independence for some of the notions of rationalizability and strict dominance, come for free.
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arxiv:cs/0608011
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we investigate two quantities of interest in a delay - tolerant mobile ad hoc network : the network capacity region and the minimum energy function. the network capacity region is defined as the set of all input rates that the network can stably support considering all possible scheduling and routing algorithms. given any input rate vector in this region, the minimum energy function establishes the minimum time average power required to support it. in this work, we consider a cell - partitioned model of a delay - tolerant mobile ad hoc network with general markovian mobility. this simple model incorporates the essential features of locality of wireless transmissions as well as node mobility and enables us to exactly compute the corresponding network capacity and minimum energy function. further, we propose simple schemes that offer performance guarantees that are arbitrarily close to these bounds at the cost of an increased delay.
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arxiv:1101.1712
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a model is studied for the theoretical description of nanoscale magnetic films with high perpendicular anisotropy. in the model the magnetic film is described in terms of single domain magnetic grains with ising - like behavior, interacting via exchange as well as via dipolar forces. additionally, the model contains an energy barrier and a coupling to an external magnetic field. disorder is taken into account in order to describe realistic domain and domain wall structures. the influence of a finite temperature as well as the dynamics can be modeled by a monte carlo simulation. many of the experimental findings can be investigated and at least partly understood by the model introduced above. for thin films the magnetisation reversal is driven by domain wall motion. the results for the field and temperature dependence of the domain wall velocity suggest that for thin films hysteresis can be described as a depinning transition of the domain walls rounded by thermal activation for finite temperatures.
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arxiv:cond-mat/9611218
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lhc run - 2 has provided intriguing di - photon signals of a new resonance around 750gev, which, if not due to statistical fluctuations, must call for new physics beyond the standard model ( sm ) at tev scale. we propose a minimal extension of the sm with a complex singlet scalar $ \ mathcal { s } $ and a doublet of vector - like quarks. the scalar sector respects cp symmetry, with its cp - odd imaginary component $ \ chi $ providing a natural dark matter ( dm ) candidate. the real component of $ \ mathcal { s } $ serves as the new resonance ( 750gev ) and explains the diphoton excess of the lhc run - 2. the new scalar degrees of freedom of $ \ mathcal { s } $ help to stabilize the higgs vacuum, and can realize the higgs inflation around gut scale, consistent with the current cosmology observations. we construct two representative samples a and b of our model for demonstration. we study the mono - jet signals of the dm production from invisible decays re $ ( \ mathcal { s } ) \ to \ chi \ chi $ at the lhc run - 2. we further derive the dm relic density bound, and analyze the constraints from direct and indirect dm detections.
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arxiv:1602.01801
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during the past two decades, methods for identifying groups with different trends in longitudinal data have become of increasing interest across many areas of research. to support researchers, we summarize the guidance from the literature regarding longitudinal clustering. moreover, we present a selection of methods for longitudinal clustering, including group - based trajectory modeling ( gbtm ), growth mixture modeling ( gmm ), and longitudinal k - means ( kml ). the methods are introduced at a basic level, and strengths, limitations, and model extensions are listed. following the recent developments in data collection, attention is given to the applicability of these methods to intensive longitudinal data ( ild ). we demonstrate the application of the methods on a synthetic dataset using packages available in r.
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arxiv:2111.05469
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phase retrieval has become a very active area of research. we will classify when phase retrieval by parseval frames passes to the naimark complement and when phase retrieval by projections passes to the orthogonal complements. we introduce a new concept we call norm retrieval and show that this is what is necessary for passing phase retrieval to complements. this leads to a detailed study of norm retrieval and its relationship to phase retrieval. one fundamental result : a frame $ \ { \ varphi _ i \ } _ { i = 1 } ^ m $ yields phase retrieval if and only if $ \ { t \ varphi _ i \ } _ { i = 1 } ^ m $ yields norm retrieval for every invertible operator $ t $.
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arxiv:1409.8266
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dynamical hysteresis is a phenomenon which arises in ferromagnetic systems below the critical temperature as a response to adiabatic variations of the external magnetic field. we study the problem in the context of the mean - field ising model with glauber dynamics, proving that for frequencies of the magnetic field oscillations of order $ n ^ { 2 / 3 } $, with $ n $ the size of the system, the " critical " hysteresis loop becomes random.
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arxiv:1107.5662
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we present a weak gravitational lensing analysis of supergroup sg1120 $ - $ 1202, consisting of four distinct x - ray - luminous groups, that will merge to form a cluster comparable in mass to coma at $ z = 0 $. these groups lie within a projected separation of 1 to 4 mpc and within $ \ delta v = 550 $ km s $ ^ { - 1 } $ and form a unique protocluster to study the matter distribution in a coalescing system. using high - resolution { \ em hst } / acs imaging, combined with an extensive spectroscopic and imaging data set, we study the weak gravitational distortion of background galaxy images by the matter distribution in the supergroup. we compare the reconstructed projected density field with the distribution of galaxies and hot x - ray emitting gas in the system and derive halo parameters for the individual density peaks. we show that the projected mass distribution closely follows the locations of the x - ray peaks and associated brightest group galaxies. one of the groups that lies at slightly lower redshift ( $ z \ approx 0. 35 $ ) than the other three groups ( $ z \ approx 0. 37 $ ) is x - ray luminous, but is barely detected in the gravitational lensing signal. the other three groups show a significant detection ( up to $ 5 \ sigma $ in mass ), with velocity dispersions between $ 355 ^ { + 55 } _ { - 70 } $ and $ 530 ^ { + 45 } _ { - 55 } $ km s $ ^ { - 1 } $ and masses between $ 0. 8 ^ { + 0. 4 } _ { - 0. 3 } \ times 10 ^ { 14 } $ and $ 1. 6 ^ { + 0. 5 } _ { - 0. 4 } \ times 10 ^ { 14 } h ^ { - 1 } m _ { \ odot } $, consistent with independent measurements. these groups are associated with peaks in the galaxy and gas density in a relatively straightforward manner. since the groups show no visible signs of interaction, this supports the picture that we are catching the groups before they merge into a cluster.
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arxiv:1507.07340
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recently, there has been a paradigm shift in stereo matching with learning - based methods achieving the best results on all popular benchmarks. the success of these methods is due to the availability of training data with ground truth ; training learning - based systems on these datasets has allowed them to surpass the accuracy of conventional approaches based on heuristics and assumptions. many of these assumptions, however, had been validated extensively and hold for the majority of possible inputs. in this paper, we generate a matching volume leveraging both data with ground truth and conventional wisdom. we accomplish this by coalescing diverse evidence from a bidirectional matching process via random forest classifiers. we show that the resulting matching volume estimation method achieves similar accuracy to purely data - driven alternatives on benchmarks and that it generalizes to unseen data much better. in fact, the results we submitted to the kitti and eth3d benchmarks were generated using a classifier trained on the middlebury 2014 dataset.
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arxiv:1804.01967
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$ w ^ + w ^ - $ production is one of the golden channels for testing the standard model as well for searches beyond the standard model. we discuss many new subleading processes for inclusive production of $ w ^ + w ^ - $ pairs generally not included in the litterature so far. we focus mainly on photon - photon induced processes. we include elastic - elastic, elastic - inelastic, inelastic - elastic and inelastic - inelastic contributions. we also calculate the contributions with resolved photons including the partonic substructure of the virtual photon. predictions for the total cross section and differential distributions in $ w $ - boson rapidity and transverse momentum as well as $ ww $ invariant mass are presented. the $ \ gamma \ gamma $ components only constitute about 1 - 2 \ % of the inclusive $ w ^ + w ^ - $ cross section but increases up to about 10 \ % at large $ w ^ { \ pm } $ transverse momenta, and are even comparable to the dominant $ q \ bar q $ component at large $ m _ { ww } $, i. e. are much larger than the $ g g \ to w ^ + w ^ - $ one.
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arxiv:1409.1803
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we introduce a method to enforce some symmetries starting from a trial wave - function prepared on quantum computers that might not respect these symmetries. the technique eliminates the necessity for performing the projection on the quantum computer itself. instead, this task is conducted as a post - processing step on the system ' s " classical shadow ". illustrations of the approach are given for the parity, particle number, and spin projectors that are of particular interest in interacting many - body systems. we compare the method with another classical post - processing technique based on direct measurements of the quantum register. we show that the present scheme can be competitive to predict observables on symmetry - restored states once optimization through derandomization is employed. the technique is illustrated through its application to compute the projected energy for the pairing model hamiltonian.
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arxiv:2311.04571
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we consider a constrained version of the shortest path problem on the complete graphs whose edges have independent random lengths and costs. we establish the asymptotic value of the minimum length as a function of the cost - budget within a wide range.
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arxiv:2005.12241
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this book is an invitation to discover advanced topics in category theory through concrete, real - world examples. it aims to give a tour : a gentle, quick introduction to guide later exploration. the tour takes place over seven sketches, each pairing an evocative application, such as databases, electric circuits, or dynamical systems, with the exploration of a categorical structure, such as adjoint functors, enriched categories, or toposes. no prior knowledge of category theory is assumed. a feedback form for typos, comments, questions, and suggestions is available here : https : / / docs. google. com / document / d / 160g9ofcp5dwt8stn7txdvx83djnnf7d5gml0 _ fod5wg / edit
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arxiv:1803.05316
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it follows from oseledec multiplicative ergodic theorem ( or kingman ' s sub - additional ergodic theorem ) that the set of ` non - typical ' points for which the oseledec averages of a given continuous cocycle diverge has zero measure with respect to any invariant probability measure. in strong contrast, for any h $ \ ddot { o } $ der continuous cocycles over hyperbolic systems, in this article we show that either all ergodic measures have same maximal lyapunov exponents or the set of lyapunov ` non - typical ' points have full topological entropy and packing topological entropy. moreover, we give an estimate of bowen hausdorff entropy from below.
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arxiv:1505.04345
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in this paper we aim at addressing the globalization problem of hamilton - dedonder - weyl equations on a local $ k $ - symplectic framework and we introduce the notion of { \ it locally conformal $ k $ - symplectic ( l. c. k - s. ) manifolds }. this formalism describes the dynamical properties of physical systems that locally behave like multi - hamiltonian systems. here, we describe the local hamiltonian properties of such systems, but we also provide a global outlook by introducing the global lee one - form approach. in particular, the dynamics will be depicted with the aid of the hamilton - - jacobi equation, which is specifically proposed in a l. c. k - s manifold.
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arxiv:1911.05962
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we study the definability of ultrafilter bases on $ \ omega $ in the sense of descriptive set theory. as a main result we show that there is no coanalytic base for a ramsey ultrafilter, while in $ l $ we can construct $ \ pi ^ 1 _ 1 $ p - point and q - point bases. we also show that the existence of a $ \ mathbf \ delta ^ 1 _ { n + 1 } $ ultrafilter is equivalent to that of a $ \ mathbf \ pi ^ 1 _ n $ ultrafilter base, for $ n \ in \ omega $. moreover we introduce a borel version of the classical ultrafilter number and make some observations.
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arxiv:1912.09138
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because of lunar librations, the retroreflectors left on the moon do not, in general, face directly at the earth. usually this is regarded as a disadvantage. it results in a spread of arrival times, because each cube that comprises the retroreflector is at a slightly different distance from the earth. however, we can turn this same effect into an advantage. using pulses and detectors somewhat faster than those currently used for lunar ranging, we can resolve at least some of the structure of a retroreflector, at least when the libration angles are large. this additional structure in the transfer function means that a unique mm level fit can be obtained with many fewer photons. fitting to the expected reflector transfer function in general requires fewer photons than straight averaging, and smoothly reduces to averaging in the cases where no structure can be resolved. the gains from resolving the reflectors are largest at large libration angles, exactly the case where averaging is most inefficient. in these cases the number of photons needed can be reduced by an order of magnitude or more. analysis shows that angles for which the gain is very high happen several times each month, with the details depending on the exact librations. experimental validation of this technique should be possible with existing slr stations and mockups of the lunar reflectors.
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arxiv:gr-qc/0504009
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we give a survey about the runge approximation problem for a holomorphic function defined on the unit ball of a complex banach space.
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arxiv:1404.1726
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in scenarios motivated by string theories, it is possible to have extra kaluza - klein dimensions compactified to rather large magnitudes, leading to large effects of gravity at scales down to a tev. the effect of the spin - 2 kaluza - klein modes on the deep - inelastic cross - section at hera is investigated. we find that the data can be used to obtain bounds on the effective low energy scale, $ m _ s $.
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arxiv:hep-ph/9812486
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there are several approaches for using computers in deriving mathematical proofs. for their illustration, we provide an in - depth study of using computer support for proving one complex combinatorial conjecture - - correctness of a strategy for the chess krk endgame. the final, machine verifiable, result presented in this paper is that there is a winning strategy for white in the krk endgame generalized to $ n \ times n $ board ( for natural $ n $ greater than $ 3 $ ). we demonstrate that different approaches for computer - based theorem proving work best together and in synergy and that the technology currently available is powerful enough for providing significant help to humans deriving complex proofs.
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arxiv:1801.07528
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explicit string models which can realize inflation and low - energy supersymmetry are notoriously difficult to achieve. given that sequestering requires very specific configurations, supersymmetric particles are in general expected to be very heavy implying that the neutralino dark matter should be overproduced in a standard thermal history. however, in this paper we point out that this is generically not the case since early matter domination driven by string moduli can dilute the dark matter abundance down to the observed value. we argue that generic features of string compactifications, namely a high supersymmetry breaking scale and late time epochs of modulus domination, might imply superheavy neutralino dark matter with mass around $ 10 ^ { 10 } - 10 ^ { 11 } $ gev. interestingly, this is the right range to explain the recent detection of ultra - high - energy neutrinos by icecube and anita via dark matter decay.
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arxiv:2010.03573
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##s lie among star - forming regions, except for highly spinning, high accretion rate hmbhs. in summary, the bels expected from hmbhs would be hard to detect using the current optical facilities. from 100 to $ 10 ^ { 12 } m _ { \ odot } $, the emission lines used to detect agn only have high ew in the $ 10 ^ 6 - 10 ^ 9 m _ { \ odot } $ window, where most agn are found. this selection effect may be distorting reported distributions of $ m _ { bh } $.
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arxiv:2007.01438
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the ordering temperature of a quasi - one - dimensional system, consisting of weakly interacting quantum spin - 1 / 2 chains with antiferromagnetic spin - frustrating couplings ( or zig - zag ladder ) is calculated. the results show that a quantum critical point between two phases of the one - dimensional subsystem plays a crucial role. if the one - dimensional subsystem is in the antiferromagnetic - like phase in the ground state, similar to the phase of a spin chain without frustration, weak couplings yield magnetic ordering of the neel type. for intra - chain spin - frustrating interactions larger than the critical one ( at which the quantum phase transition takes place ), the quasi - one - dimensional spin system manifests a spiral magnetic incommensurate ordering. the obtained results of our quantum theory are compared with the quasi - classical approximations. the calculated features of magnetic ordering are expected to be generic for weakly coupled quantum spin chains with gapless excitations and spin - frustrating nearest and next - nearest neighbor interactions.
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arxiv:0806.1074
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generalizing the classical result of bohr, we show that if an n - variable power series converges in an n - circular bounded complete domain d and its sum has modulus less than 1, then the sum of the maximum of the moduli of the terms is less than 1 in the homothetic domain r * d, where r = 1 - ( 2 / 3 ) ^ ( 1 / n ). this constant is near to the best one for the domain d = { z : | z _ 1 | +... + | z _ n | < 1 }.
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arxiv:math/9804102
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as mechanical devices in the nano / micro length scale are increasingly employed, it is crucial to understand nanoscale friction and wear especially at technically relevant sliding velocities. accordingly, a novel technique has been developed for friction coefficient mapping ( fcm ), leveraging recent advances in high speed afm. the technique efficiently acquires friction versus force curves based on a sequence of images at a single location, each with incrementally lower loads. as a result, true maps of the coefficient of friction can be uniquely calculated for heterogeneous surfaces. these parameters are determined at a scan velocity as fast as 2 mm / s for microfabricated sio2 mesas and au coated pits, yielding results that are identical to traditional speed measurements despite being ~ 1000 times faster. to demonstrate the upper limit of sliding velocity for the custom setup, the friction properties of mica are reported from 200 { \ mu } m / sec up to 2 cm / sec. while fcm is applicable to any afm and scanning speed, quantitative nanotribology investigations of heterogeneous sliding or rolling components are therefore uniquely possible, even at realistic velocities for devices such as mems, biological implants, or data storage systems.
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arxiv:1406.2797
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we present a high - resolution ( r = 140, 000 ) spectrum of the bright quasar he0001 - 2340 ( z = 2. 26 ), obtained with espresso at the very large telescope. we analyse three systems at z = 0. 45, z = 1. 65, and z = 2. 19 using multiple - component voigt - profile fitting. we also compare our spectrum with those obtained with vlt / uves, covering a total period of 17 years. we disentangle turbulent and thermal broadening in many components spread over about 400 km / s in the z ~ 2. 19 sub - dla system. we derive an average temperature of 16000 + / - 1300 k, i. e., about twice the canonical value of the warm neutral medium in the galactic interstellar medium. a comparison with other high - z, low - metallicity absorbers reveals an anti - correlation between gas temperature and total hi column density. although requiring confirmation, this could be the first observational evidence of a thermal decrease with galacto - centric distance, i. e., we may be witnessing a thermal transition between the circum - galactic medium and the cooler ism. we revisit the mg isotopic ratios at z = 0. 45 and z = 1. 65 and constrain them to be xi = ( 26mg + 25mg ) / 24mg < 0. 6 and < 1. 4 in these two systems, respectively. these values are consistent with the standard solar ratio, i. e., we do not confirm strong enhancement of heavy isotopes previously inferred from uves data. finally, we confirm the partial coverage of the quasar emission - line region by a fei - bearing cloud in the z = 0. 45 system and present evidence for velocity sub - structure of the gas that has doppler parameters of the order of only ~ 0. 3 km / s. this work demonstrates the uniqueness of high - fidelity, high - resolution optical spectrographs on large telescopes as tools to investigate the thermal state of the gas in and around galaxies as well as its spatial and velocity structure on small scales, and to constrain the associated stellar nucleosynthetic history. [ abridged ]
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arxiv:2105.00697
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we prove that the free uniform spanning forest of any bounded degree proper plane graph is connected almost surely, answering a question of benjamini, lyons, peres and schramm. we provide a quantitative form of this result, calculating the critical exponents governing the geometry of the uniform spanning forests of transient proper plane graphs with bounded degrees and codegrees. we find that the same exponents hold universally over this entire class of graphs provided that measurements are made using the hyperbolic geometry of their circle packings rather than their usual combinatorial geometry.
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arxiv:1603.07320
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this is a course on random matrix theory which includes traditional as well as advanced topics presented with an extensive use of classical logarithmic plasma analogy and that of the quantum systems of one - dimensional interacting fermions with inverse square interaction ( calogero - sutherland model ). certain non - invariant random matrix ensembles are also considered with the emphasis on the eigenfunction statistics in them. the course can also be viewed as introduction to theory of localization where the ( non - invariant ) random matrix ensembles play a role of the toy models to illustrate functional methods based on super - vector / super - matrix representations.
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arxiv:0911.0639
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the exponential run time of quantum simulators on classical machines and long queue times and high costs of real quantum devices present significant challenges in the efficient optimization of variational quantum algorithms ( vqas ) like variational quantum eigensolver ( vqe ), quantum approximate optimization algorithm ( qaoa ) and quantum neural networks ( qnns ). to address these limitations, we propose a new approach, dypp ( dynamic parameter prediction ), which accelerates the convergence of vqas by exploiting regular trends in the parameter weights to update parameters. we introduce two techniques for optimal prediction performance namely, naive prediction ( nap ) and adaptive prediction ( adap ). through extensive experimentation and training of multiple qnn models on various datasets, we demonstrate that dypp offers a speedup of approximately $ 2. 25 \ times $ compared to standard training methods, while also providing improved accuracy ( up to $ 2. 3 \ % $ higher ) and loss ( up to $ 6. 1 \ % $ lower ) with low storage and computational overheads. we also evaluate dypp ' s effectiveness in vqe for molecular ground - state energy estimation and in qaoa for graph maxcut. our results show that on average, dypp leads to speedup of up to $ 3. 1 \ times $ for vqe and $ 2. 91 \ times $ for qaoa, compared to traditional optimization techniques, while using up to $ 3. 3 \ times $ lesser shots ( i. e., repeated circuit executions ). even under hardware noise, dypp outperforms existing optimization techniques, delivering upto $ 3. 33 \ times $ speedup and $ 2. 5 \ times $ fewer shots, thereby enhancing efficiency of vqas.
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arxiv:2307.12449
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in monolayer transition metal dichalcogenides helicity - dependent charge and spin photocurrents can emerge, even without applying any electrical bias, due to circular photogalvanic and photon drag effects. exploiting such circular photocurrents ( cpc ) in devices, however, requires better understanding of their behavior and physical origin. here, we present symmetry, spectral, and electrical characteristics of cpc from excitonic interband transitions in a mose2 monolayer. the dependence on bias and gate voltages reveals two different cpc contributions, dominant at different voltages and with different dependence on illumination wavelength and incidence angles. we theoretically analyze symmetry requirements for effects that can yield cpc and compare these with the observed angular dependence and symmetries that occur for our device geometry. this reveals that the observed cpc effects require a reduced device symmetry, and that effects due to berry curvature of the electronic states do not give a significant contribution.
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arxiv:1803.08289
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we present deep chandra, xmm - newton, giant metrewave radio telescope and halpha observations of the group - group merger ngc 6338. x - ray imaging and spectral mapping show that as well as trailing tails of cool, enriched gas, the two cool cores are embedded in an extensive region of shock heated gas with temperatures rising to ~ 5 kev. the velocity distribution of the member galaxies show that the merger is occurring primarily along the line of sight, and we estimate that the collision has produced shocks of mach number m = 2. 3 or greater, making this one of the most violent mergers yet observed between galaxy groups. both cool cores host potential agn cavities and halpha nebulae, indicating rapid radiative cooling. in the southern cool core around ngc 6338, we find that the x - ray filaments associated with the halpha nebula have low entropies ( < 10 kev cm ^ 2 ) and short cooling times ( ~ 200 - 300 myr ). in the northern core we identify an halpha cloud associated with a bar of dense, cool x - ray gas offset from the dominant galaxy. we find no evidence of current jet activity in either core. we estimate the total mass of the system and find that the product of this group - group merger will likely be a galaxy cluster.
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arxiv:1906.07710
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a formalism for electronic - structure calculations is presented that is based on the functional renormalization group ( frg ). the traditional frg has been formulated for systems that exhibit a translational symmetry with an associated fermi surface, which can provide the organization principle for the renormalization group ( rg ) procedure. we here advance an alternative formulation, where the rg - flow is organized in the energy - domain rather than in k - space. this has the advantage that it can also be applied to inhomogeneous matter lacking a band - structure, such as disordered metals or molecules. the energy - domain frg ( { \ epsilon } frg ) presented here accounts for fermi - liquid corrections to quasi - particle energies and particle - hole excitations. it goes beyond the state of the art gw - bse, because in { \ epsilon } frg the bethe - salpeter equation ( bse ) is solved in a self - consistent manner. an efficient implementation of the approach that has been tested against exact diagonalization calculations and calculations based on the density matrix renormalization group is presented. similar to the conventional frg, also the { \ epsilon } frg is able to signalize the vicinity of an instability of the fermi - liquid fixed point via runaway flow of the corresponding interaction vertex. embarking upon this fact, in an application of { \ epsilon } frg to the spinless disordered hubbard model we calculate its phase - boundary in the plane spanned by the interaction and disorder strength. finally, an extension of the approach to finite temperatures and spin s = 1 / 2 is also given.
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arxiv:1605.07024
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in this paper, we introduce a hybrid search for attention - based neural machine translation ( nmt ). a target phrase learned with statistical mt models extends a hypothesis in the nmt beam search when the attention of the nmt model focuses on the source words translated by this phrase. phrases added in this way are scored with the nmt model, but also with smt features including phrase - level translation probabilities and a target language model. experimental results on german - > english news domain and english - > russian e - commerce domain translation tasks show that using phrase - based models in nmt search improves mt quality by up to 2. 3 % bleu absolute as compared to a strong nmt baseline.
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arxiv:1708.03271
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large language models ( llms ) have emerged as powerful generative artificial intelligence solutions which can be applied to several fields and areas of work. this paper presents results and reflection of an experiment done to use the model gpt 3. 5 - turbo to emulate some aspects of an inductive thematic analysis. previous research on this subject has largely worked on conducting deductive analysis. thematic analysis is a qualitative method for analysis commonly used in social sciences and it is based on interpretations made by the human analyst ( s ) and the identification of explicit and latent meanings in qualitative data. attempting an analysis based on human interpretation with an llm clearly is a provocation but also a way to learn something about how these systems can or cannot be used in qualitative research. the paper presents the motivations for attempting this emulation, it reflects on how the six steps to a thematic analysis proposed by braun and clarke can at least partially be reproduced with the llm and it also reflects on what are the outputs produced by the model. the paper used two existing datasets of open access semi - structured interviews, previously analysed with thematic analysis by other researchers. it used the previously produced analysis ( and the related themes ) to compare with the results produced by the llm. the results show that the model can infer at least partially some of the main themes. the objective of the paper is not to replace human analysts in qualitative analysis but to learn if some elements of llm data manipulation can to an extent be of support for qualitative research.
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arxiv:2305.13014
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we explore the relationship among three coronal mass ejections ( cmes ), observed on 28 october 2003, 7 november 2004, and 20 january 2005, the type ii burst - associated shock waves in the corona and solar wind, as well as the arrival of their related shock waves and magnetic clouds at 1 au. using six different coronal / interplanetary density models, we calculate the speeds of shocks from the frequency drifts observed in metric and decametric radio wave data. we compare these speeds with the velocity of the cmes as observed in the plane - of - the - sky white - light observations and calculated with a cone model for the 7 november 2004 event. we then follow the propagation of the ejecta using interplanetary scintillation ( ips ) measurements, which were available for the 7 november 2004 and 20 january 2005 events. finally, we calculate the travel time of the interplanetary ( ip ) shocks between the sun and earth and discuss the velocities obtained from the different data. this study highlights the difficulties in making velocity estimates that cover the full cme propagation time.
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arxiv:0711.3168
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in this paper, we propose a mesh - free numerical method for solving elliptic pdes on unknown manifolds, identified with randomly sampled point cloud data. the pde solver is formulated as a spectral method where the test function space is the span of the leading eigenfunctions of the laplacian operator, which are approximated from the point cloud data. while the framework is flexible for any test functional space, we will consider the eigensolutions of a weighted laplacian obtained from a symmetric radial basis function ( rbf ) method induced by a weak approximation of a weighted laplacian on an appropriate hilbert space. especially, we consider a test function space that encodes the geometry of the data yet does not require us to identify and use the sampling density of the point cloud. to attain a more accurate approximation of the expansion coefficients, we adopt a second - order tangent space estimation method to improve the rbf interpolation accuracy in estimating the tangential derivatives. this spectral framework allows us to efficiently solve the pde many times subjected to different parameters, which reduces the computational cost in the related inverse problem applications. in a well - posed elliptic pde setting with randomly sampled point cloud data, we provide a theoretical analysis to demonstrate the convergent of the proposed solver as the sample size increases. we also report some numerical studies that show the convergence of the spectral solver on simple manifolds and unknown, rough surfaces. our numerical results suggest that the proposed method is more accurate than a graph laplacian - based solver on smooth manifolds. on rough manifolds, these two approaches are comparable. due to the flexibility of the framework, we empirically found improved accuracies in both smoothed and unsmoothed stanford bunny domains by blending the graph laplacian eigensolutions and rbf interpolator.
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arxiv:2210.10527
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in deep learning, test - time adaptation has gained attention as a method for model fine - tuning without the need for labeled data. a prime exemplification is the recently proposed test - time prompt tuning for large - scale vision - language models such as clip. unfortunately, these prompts have been mainly developed to improve accuracy, overlooking the importance of calibration, which is a crucial aspect for quantifying prediction uncertainty. however, traditional calibration methods rely on substantial amounts of labeled data, making them impractical for test - time scenarios. to this end, this paper explores calibration during test - time prompt tuning by leveraging the inherent properties of clip. through a series of observations, we find that the prompt choice significantly affects the calibration in clip, where the prompts leading to higher text feature dispersion result in better - calibrated predictions. introducing the average text feature dispersion ( atfd ), we establish its relationship with calibration error and present a novel method, calibrated test - time prompt tuning ( c - tpt ), for optimizing prompts during test - time with enhanced calibration. through extensive experiments on different clip architectures and datasets, we show that c - tpt can effectively improve the calibration of test - time prompt tuning without needing labeled data. the code is publicly accessible at https : / / github. com / hee - suk - yoon / c - tpt.
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arxiv:2403.14119
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question answering has recently received high attention from artificial intelligence communities due to the advancements in learning technologies. early question answering models used rule - based approaches and moved to the statistical approach to address the vastly available information. however, statistical approaches are shown to underperform in handling the dynamic nature and the variation of language. therefore, learning models have shown the capability of handling the dynamic nature and variations in language. many deep learning methods have been introduced to question answering. most of the deep learning approaches have shown to achieve higher results compared to machine learning and statistical methods. the dynamic nature of language has profited from the nonlinear learning in deep learning. this has created prominent success and a spike in work on question answering. this paper discusses the successes and challenges in question answering question answering systems and techniques that are used in these challenges.
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arxiv:1904.05276
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we use shor ' s algorithm for the computation of elliptic curve private keys as a case study for resource estimates in the silicon - photonics - inspired active - volume architecture. here, a fault - tolerant surface - code quantum computer consists of modules with a logarithmic number of non - local inter - module connections, modifying the algorithmic cost function compared to 2d - local architectures. we find that the non - local connections reduce the cost per key by a factor of 300 - 700 depending on the operating regime. at 10 % threshold, assuming a 10 - $ \ mu $ s code cycle and non - local connections, one key can be generated every 10 minutes using 6000 modules with 1152 physical qubits each. by contrast, a device with strict 2d - local connectivity requires more qubits and produces one key every 38 hours. we also find simple architecture - independent algorithmic modifications that reduce the toffoli count per key by up to a factor of 5. these modifications involve reusing the stored state for multiple keys and spreading the cost of the modular division operation over multiple parallel instances of the algorithm.
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arxiv:2306.08585
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5g will enable and greatly accelerate digital transformation of vertical sectors. in the longer term this will evolve from per - vertical connectivity services in 5g to the emergence of the 6g - enabled internet of verticals ( 6g - iov ). in this paper we describe and examine enabling technologies for this further transformation of verticals and examine some examples of 6g - iov, next generation cloud manufacturing and manufacturing as a service, next generation smart energy grids and the internet of robotics ( ior ).
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arxiv:2112.10352
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there is growing interest in the language developed by agents interacting in emergent - communication settings. earlier studies have focused on the agents ' symbol usage, rather than on their representation of visual input. in this paper, we consider the referential games of lazaridou et al. ( 2017 ) and investigate the representations the agents develop during their evolving interaction. we find that the agents establish successful communication by inducing visual representations that almost perfectly align with each other, but, surprisingly, do not capture the conceptual properties of the objects depicted in the input images. we conclude that, if we are interested in developing language - like communication systems, we must pay more attention to the visual semantics agents associate to the symbols they use.
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arxiv:1808.10696
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we extend the computations from our previous paper arxiv : 2005. 07054 to determine the maximum number of rational points on a curve over $ \ mathbb { f } _ 3 $ and $ \ mathbb { f } _ 4 $ with fixed gonality and small genus. we find, for example, that there is no curve of genus 5 and gonality 6 over a finite field. we propose two conjectures based on our data. first, an optimal curve of genus $ g $ has gonality at most $ \ lfloor \ frac { g + 3 } { 2 } \ rfloor $. second, a curve of gonality $ \ gamma $ and large genus over $ \ mathbb { f } _ q $ has $ \ gamma ( q + 1 ) $ rational points.
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arxiv:2010.07992
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