text
stringlengths 1
3.65k
| source
stringlengths 15
79
|
|---|---|
we examine the early angular momentum history of stars in young clusters via 197 photometric periods in fields flanking the orion nebula cluster ( onc ), 81 photometric periods in ngc 2264, and 202 measurements of v sin i in the onc itself. we show that pms stars spanning an age range from 0. 1 to 3 myr do not appear to conserve stellar angular momentum as they evolve down their convective tracks, but instead preserve the same range of periods even though they have contracted by about a factor of three. this result seems to require a mechanism that regulates the angular velocities of young stars. we discuss several candidate mechanisms. the most plausible appears to be disk - locking, though most of our stars do not have ( i - k ) excesses suggestive of disks. however, a decisive test of this hypothesis requires a more sensitive diagnostic than the ( i - k ) excesses used here.
|
arxiv:astro-ph/0203384
|
the $ \ imath $ hall algebra of the projective line is by definition the twisted semi - derived ringel - hall algebra of the category of $ 1 $ - periodic complexes of coherent sheaves on the projective line. this $ \ imath $ hall algebra is shown to realize the universal $ q $ - onsager algebra ( i. e., $ \ imath $ quantum group of split affine $ a _ 1 $ type ) in its drinfeld type presentation. the $ \ imath $ hall algebra of the kronecker quiver was known earlier to realize the same algebra in its serre type presentation. we then establish a derived equivalence which induces an isomorphism of these two $ \ imath $ hall algebras, explaining the isomorphism of the $ q $ - onsager algebra under the two presentations.
|
arxiv:2010.00646
|
it is shown that if the sneutrino is the second lightest susy particle, then the decay products of squarks and gluinos produced at the tevatron collider tend to have i ) more leptons, ii ) smaller number of jets and iii ) two or more carriers of missing e _ t. this may relax the existing limits on the squark and gluino masses. this effect is likely to be even more striking as these limits improve with accumulation of data. numerical results for signal cross sections are presented and compared with the ones obtained without a light sneutrino. the possibilities of accommodating this scenario in models motivated by n = 1 sugra are discussed.
|
arxiv:hep-ph/9609413
|
likelihood - free inference involves inferring parameter values given observed data and a simulator model. the simulator is computer code which takes parameters, performs stochastic calculations, and outputs simulated data. in this work, we view the simulator as a function whose inputs are ( 1 ) the parameters and ( 2 ) a vector of pseudo - random draws. we attempt to infer all these inputs conditional on the observations. this is challenging as the resulting posterior can be high dimensional and involve strong dependence. we approximate the posterior using normalizing flows, a flexible parametric family of densities. training data is generated by likelihood - free importance sampling with a large bandwidth value epsilon, which makes the target similar to the prior. the training data is " distilled " by using it to train an updated normalizing flow. the process is iterated, using the updated flow as the importance sampling proposal, and slowly reducing epsilon so the target becomes closer to the posterior. unlike most other likelihood - free methods, we avoid the need to reduce data to low dimensional summary statistics, and hence can achieve more accurate results. we illustrate our method in two challenging examples, on queuing and epidemiology.
|
arxiv:1910.03632
|
gaussian smoothing ( gs ) is a derivative - free optimization ( dfo ) algorithm that estimates the gradient of an objective using perturbations of the current parameters sampled from a standard normal distribution. we generalize it to sampling perturbations from a larger family of distributions. based on an analysis of dfo for non - convex functions, we propose to choose a distribution for perturbations that minimizes the mean squared error ( mse ) of the gradient estimate. we derive three such distributions with provably smaller mse than gaussian smoothing. we conduct evaluations of the three sampling distributions on linear regression, reinforcement learning, and dfo benchmarks in order to validate our claims. our proposal improves on gs with the same computational complexity, and are usually competitive with and often outperform guided es and orthogonal es, two computationally more expensive algorithms that adapt the covariance matrix of normally distributed perturbations.
|
arxiv:2211.14721
|
vacuum and medium modified fragmentation functions are used to study the properties of hadrons produced in hard interactions, in $ p $ - $ p $ and $ a $ - $ a $ collisions, respectively. we study the modification of reconstructed jets and high transverse momentum ( high - $ p _ \ mathrm { t } $ ) hadrons as they propagate through a dense medium. jets and jet modification are studied within the framework of a factorized jet function. the vacuum jet function is found consistent with pythia simulations. both the modification of the fragmentation function and the jet function are carried out within the identical higher - twist energy loss formalism. this approach is then extended to di - hadron production within a jet. its further extension to a " di - prong " function and its application to the soft - drop measurements are discussed. the methodology of extending these semi - analytical calculations to full monte - carlo simulations is outlined. all calculations are carried out within a ( 2 + 1 ) - d viscous hydrodynamic simulation and compared to experimental data from a variety of collision energies.
|
arxiv:1901.03635
|
this paper studies hamiltonization of nonholonomic systems using geometric tools. by making use of symmetries and suitable first integrals of the system, we explicitly define a global 2 - form for which the gauge transformed nonholonomic bracket gives rise to a new bracket on the reduced space codifying the nonholonomic dynamics and carrying an almost symplectic foliation ( determined by the common level sets of the first integrals ). in appropriate coordinates, this 2 - form is shown to agree with the one previously introduced locally in [ 34 ]. we use our coordinate - free viewpoint to study various geometric features of the reduced brackets. we apply our formulas to obtain a new geometric proof of the hamiltonization of a homogeneous ball rolling without sliding in the interior side of a convex surface of revolution using our formulas.
|
arxiv:1904.00235
|
xai with natural language processing aims to produce human - readable explanations as evidence for ai decision - making, which addresses explainability and transparency. however, from an hci perspective, the current approaches only focus on delivering a single explanation, which fails to account for the diversity of human thoughts and experiences in language. this paper thus addresses this gap, by proposing a generative xai framework, interaction ( explain and predict then query with contextual conditional variational auto - encoder ). our novel framework presents explanation in two steps : ( step one ) explanation and label prediction ; and ( step two ) diverse evidence generation. we conduct intensive experiments with the transformer architecture on a benchmark dataset, e - snli. our method achieves competitive or better performance against state - of - the - art baseline models on explanation generation ( up to 4. 7 % gain in bleu ) and prediction ( up to 4. 4 % gain in accuracy ) in step one ; it can also generate multiple diverse explanations in step two.
|
arxiv:2209.01061
|
we show that a low finesse cavity can be efficient for detecting neutral atoms. the low finesse can be compensated for by decreasing the mode waist of the cavity. we have used a near concentric resonator with a beam waist of 12 $ \ mu $ m and a finesse of only 1100 to detect magnetically guided rb atoms with a detection sensitivity of 0. 1 atom in the mode volume. for future experiments on single atom detection and cavity qed applications, it should be very beneficial to use miniaturized optical resonator integrated on atom chips.
|
arxiv:physics/0510166
|
within a case study on the protein - protein interaction network ( pin ) of drosophila melanogaster we investigate the relation between the network ' s spectral properties and its structural features such as the prevalence of specific subgraphs or duplicate nodes as a result of its evolutionary history. the discrete part of the spectral density shows fingerprints of the pin ' s topological features including a preference for loop structures. duplicate nodes are another prominent feature of pins and we discuss their representation in the pin ' s spectrum as well as their biological implications.
|
arxiv:q-bio/0405021
|
machine learning ( ml ) models are applied in an increasing variety of domains. the availability of large amounts of data and computational resources encourages the development of ever more complex and valuable models. these models are considered intellectual property of the legitimate parties who have trained them, which makes their protection against stealing, illegitimate redistribution, and unauthorized application an urgent need. digital watermarking presents a strong mechanism for marking model ownership and, thereby, offers protection against those threats. this work presents a taxonomy identifying and analyzing different classes of watermarking schemes for ml models. it introduces a unified threat model to allow structured reasoning on and comparison of the effectiveness of watermarking methods in different scenarios. furthermore, it systematizes desired security requirements and attacks against ml model watermarking. based on that framework, representative literature from the field is surveyed to illustrate the taxonomy. finally, shortcomings and general limitations of existing approaches are discussed, and an outlook on future research directions is given.
|
arxiv:2009.12153
|
given $ e _ 0, e _ 1, e, f $ rearrangement invariant spaces, $ a, b, b _ 0, b _ 1 $ slowly varying functions and $ 0 \ leq \ theta _ 0 < \ theta _ 1 \ leq 1 $, we characterize the interpolation space $ $ ( \ overline { x } _ { \ theta _ 0, b _ 0, e _ 0 }, \ overline { x } ^ { \ mathcal r } _ { \ theta _ 1, b _ 1, e _ 1, a, f } ) _ { \ theta, b, e } \ quad \ text { and } \ quad ( \ overline { x } ^ { \ mathcal l } _ { \ theta _ 0, b _ 0, e _ 0, a, f }, \ overline { x } _ { \ theta _ 1, b _ 1, e _ 1 } ) _ { \ theta, b, e }, $ $ for all possible values of $ \ theta \ in [ 0, 1 ] $. applications to interpolation identities for grand and small lebesgue spaces, gamma spaces and $ a $ and $ b $ - type spaces are given.
|
arxiv:2010.06940
|
the study of biochemical pathways usually focuses on a small section of a protein interactions network. two distinct sources contribute to the noise in such a system : intrinsic noise, inherent in the studied reactions, and extrinsic noise generated in other parts of the network or in the environment. we study the effect of extrinsic noise entering the system through a nonlinear uptake reaction which acts as a nonlinear filter. varying input noise intensity varies the mean of the noise after the passage through the filter, which changes the stability properties of the system. the steady - state displacement due to small noise is independent on the kinetics of the system but it only depends on the nonlinearity of the input function. for monotonically increasing and concave input functions such as the michaelis - menten uptake rate, we give a simple argument based on the small - noise expansion, which enables qualitative predictions of the steady - state displacement only by inspection of experimental data : when weak and rapid noise enters the system through a michaelis - menten reaction, then the graph of the system ' s steady states vs. the mean of the input signal always shifts to the right as noise intensity increases. we test the predictions on two models of lac operon, where tmg / lactose uptake is driven by a michaelis - menten enzymatic process. we show that as a consequence of the steady state displacement due to fluctuations in extracellular tmg / lactose concentration the lac switch responds in an asymmetric manner : as noise intensity increases, switching off lactose metabolism becomes easier and switching it on becomes more difficult.
|
arxiv:0905.3502
|
a radioactive beam of 20na is stopped in a gas cell filled with ne gas. the stopped particles are polarized by optical pumping. the degree of polarization that can be achieved is studied. a maximum polarization of 50 % was found. the dynamic processes in the cell are described with a phenomenological model.
|
arxiv:1601.03599
|
the current framework of internet interconnections, based on transit and settlement - free peering relations, has systemic problems that often cause peering disputes. we propose a new techno - economic interconnection framework called nash - peering, which is based on the principles of nash bargaining in game theory and economics. nash - peering constitutes a radical departure from current interconnection practices, providing a broader and more economically efficient set of interdomain relations. in particular, the direction of payment is not determined by the direction of traffic or by rigid customer - provider relationships but based on which as benefits more from the interconnection. we argue that nash - peering can address the root cause of various types of peering disputes.
|
arxiv:1610.01314
|
we report the discovery of two new wolf - rayet ( wr ) galaxies : mrk ~ 1039, and f08208 $ + $ 2816. two broad wr bumps at 5808 \ aa ~ and 4650 \ aa ~ indicate the presence of wce and wnl star population in all two sources. we also confirm the presenceof wr features in mrk ~ 35, previously detected in a different position. the observed equivalent width of the wr bump at 4650 \ aa ~ and the derived number ratios of wr / ( wr $ + $ o ) imply that star formation in these sources takes place inshort burst duration. comparisons with the recent models of wr populations in young starbursts with the observed ew ( \ heii ) / ew ( \ civ ) / ew ( wrbump ) and their relative intensitie provide an indication that the stellar initial mass function in some wr galaxies might not be salpeter - like. it is interesting to find that the luminous iras source, f08208 $ + $ 2816, has little dust reddening, probably because of the existence of a powerful superwind. by comparisons with other starbursts observed with the hopkins ultraviolet telescope, f08208 $ + $ 2816 as a merging system renders a chance to study the contribution from young starbursts to the uv background radiation in universe.
|
arxiv:astro-ph/9809188
|
taylor expansion of the equation of state of qcd suffers from shortcomings at chemical potentials $ \ mu _ b \ geq ( 2 - 2. 5 ) t $. first, one faces difficulties inherent in performing such an expansion with a limited number of coefficients ; second, higher order coefficients determined from lattice calculations suffer from a poor signal - to - noise ratio. in this work, we present a novel scheme for extrapolating the equation of state of qcd to finite, real chemical potential that can extend its reach further than previous methods. we present continuum extrapolated lattice results for the new expansion coefficients and show the thermodynamic observables up to $ \ mu _ b / t \ le3. 5 $.
|
arxiv:2102.06660
|
we report a search for $ b ^ { 0 } \ to \ eta \ eta $ with a data sample corresponding to an integrated luminosity of $ 698 \, { \ rm fb } ^ { - 1 } $ containing $ 753 \ times 10 ^ { 6 } $ $ b \ bar { b } $ pairs collected at the $ \ upsilon ( 4s ) $ resonance with the belle detector at the kekb asymmetric - energy $ e ^ { + } e ^ { - } $ collider. the branching fraction is measured to be $ \ mathcal { b } ( b ^ { 0 } \ to \ eta \ eta ) = ( 7. 6 ^ { + 2. 7 + 1. 4 } _ { - 2. 3 - 1. 6 } ) \ times 10 ^ { - 7 } $ at the level of 3. 3 standard deviations above zero, which provides the first evidence for the decay $ b ^ { 0 } \ to \ eta \ eta $.
|
arxiv:1609.03267
|
we explore the consistency relations for the three - point functions, in the squeezed limit, of scalar and tensor perturbations in single - field inflation with general initial conditions for the perturbations. for slow - roll inflation, we find that all the three - point functions of scalar and tensor perturbations with a coherent state as the initial state are identical to the three - point functions with the bunch - davies initial state. on the other hand, there is an apparent violation of some of the consistency relations for initial states that are related to the bunch - davies state by bogoliubov transformations and we identify the reason for this violation. the back - reaction calculations indicate that the three - point functions for these states can be large enough to violate the consistency relations, however, they are too small to be observed in the near future.
|
arxiv:1311.1575
|
a new iron - based superconductor, lix ( c6h16n2 ) yfe2 - zse2, with tc = 38 k has successfully been synthesized via the intercalation of lithium and hexamethylenediamine into fese. the superconducting transition has been confirmed not only by magnetic susceptibility measurements but also by electrical resistivity ones. the interlayer spacing, namely, the dicstance between neighboring fe layers, d, is 16. 225 ( 5 ) $ \ mathring { \ text { a } } $, which is the largest among those of fese - based intercalation compounds. it has been found that the dependence of tc on d in fese - based intercalation superconductors appears domic.
|
arxiv:1510.08625
|
in the inference attacks studied in quantitative information flow ( qif ), the adversary typically tries to interfere with the system in the attempt to increase its leakage of secret information. the defender, on the other hand, typically tries to decrease leakage by introducing some controlled noise. this noise introduction can be modeled as a type of protocol composition, i. e., a probabilistic choice among different protocols, and its effect on the amount of leakage depends heavily on whether or not this choice is visible to the adversary. in this work we consider operators for modeling visible and invisible choice in protocol composition, and we study their algebraic properties. we then formalize the interplay between defender and adversary in a game - theoretic framework adapted to the specific issues of qif, where the payoff is information leakage. we consider various kinds of leakage games, depending on whether players act simultaneously or sequentially, and on whether or not the choices of the defender are visible to the adversary. finally, we establish a hierarchy of these games in terms of their information leakage, and provide methods for finding optimal strategies ( at the points of equilibrium ) for both attacker and defender in the various cases. the full version of this paper can be found in arxiv : 1803. 10042
|
arxiv:1802.10465
|
we show that binned differential luminosity functions constructed using the 1 / va method have a significant systematic error for objects close to their parent sample ' s flux limit ( s ). this is particularly noticeable when luminosity functions are produced for a number of different redshift ranges as is common in the study of agn or galaxy evolution. we present a simple method of constructing a binned luminosity function which overcomes this problem and has a number of other advantages over the traditional 1 / va method. we also describe a practical method for comparing binned and model luminosity functions, by calculating the expectation values of the binned luminosity function from the model. binned luminosity functions produced by the two methods are compared for simulated data and for the large bright qso survey ( lbqs ). it is shown that the 1 / va method produces a very misleading picture of evolution in the lbqs. the binned luminosity function of the lbqs is then compared to a model two power law luminosity function undergoing pure luminosity evolution from boyle et al. ( 1991 ). the comparison is made using a model luminosity function averaged over each redshift shell, and using the expectation values for the binned luminosity function calculated from the model. the luminosity function averaged in each redshift shell gives a misleading impression that the model over predicts the number of qsos at low luminosity even when model and data are consistent. the expectation values show that there are significant differences between model and data : the model overpredicts the number of low luminosity sources at both low and high redshift. the luminosity function does not appear to steepen relative to the model as redshift increases.
|
arxiv:astro-ph/9909434
|
we present optical and near - infrared ground - based imaging results on four low - redshift damped ly - alpha ( dla ) galaxies. the corresponding dla systems were discovered in our hst spectroscopic surveys for dla lines in known strong mgii absorption - line systems toward the quasars b2 0827 + 243 ( z { dla } = 0. 525 ), pks 0952 + 179 ( z { dla } = 0. 239 ), pks 1127 - 145 ( z { dla } = 0. 313 ), and pks 1629 + 120 ( z { dla } = 0. 532 ). the dla galaxies span a mixture of morphological types from patchy, irregular, and low surface brightness to spiral galaxies. the luminosities range from 0. 02l _ k * to 1. 2l _ k *. we also discovered several extremely red objects ( eros ) in two of these fields and discuss the possibility that they are associated with the dla galaxies. these observations add to the small but growing list of dla galaxies at low redshift. at the present time, 14 dla galaxies in the redshift range 0. 05 < z < 1 have been studied. the distributions of dla galaxy properties for these 14 cases are discussed and some important trends emerge. low - luminosity dwarf galaxies with small impact parameters dominate this small sample. also, four of the five highest column density systems, which dominate in the determination of the cosmological neutral gas mass density, arise in low surface brightness dwarf galaxies. zwaan et al. have shown that only 15 % of the neutral gas at the present epoch is contained in low surface brightness galaxies. thus, if the low - redshift dla galaxy trends hold up with larger samples, it would indicate that a different population of objects is responsible for the bulk of the neutral hydrogen gas in the universe at z approx 0. 5. ( abridged )
|
arxiv:astro-ph/0211297
|
that j0439 + 1634 is the highest redshift obscured quasar with a direct measurement of the absorbing column density. the intrinsic high column density absorption can reduce the x - ray luminosity by a factor of $ 3 - 7 $, which also indicates that this quasar could be a candidate of intrinsically x - ray weak quasar.
|
arxiv:2112.10785
|
potential energy surfaces of the hydrogen molecular ion h $ _ 2 ^ + $ in the born - oppenheimer approximation are computed by means of the riccati - pad \ ' e method ( rpm ). the convergence properties of the method are analyzed for different states. the equilibrium internuclear distance, as well as the corresponding electronic plus nuclear energy, and the associated separation constants, are computed to 40 digits of accuracy for several bound states. for the ground state the same parameters are computed with more than 100 digits of accuracy. additional benchmark values of the electronic energy at different internuclear distances are given for several additional states. the software implementation of the rpm is given under a free software license. the results obtained in the present work are the most accurate available so far, and further additional benchmarks are made available through the software provided.
|
arxiv:2107.01228
|
we construct conformastat spherically symmetric spacetimes representing anisotropic fluid matter distributions from given solutions of the poisson ' s equation of newtonian gravity and its corresponding circular speed profile. as simple examples, we present three families of spherically symmetric spacetimes which we apply in constructing new models of relativistic anisotropic thick spherical shells, and of relativistic galaxy models composite by a central spherical bulge, the thick disk and the dark matter halo, writing in this case the metric in cylindrical coordinates. moreover, the geodesic motion of test particles in stable circular orbits around such structures is studied. we build anisotropic fluid sources for these spacetimes which satisfy all the energy conditions and the principal stresses are positive quantities ( pressure ).
|
arxiv:1911.05512
|
in this paper convex optimization techniques are employed for convex optimization problems in infinite dimensional hilbert spaces. a first order optimality condition is given. let $ f : \ mathbb { r } ^ { n } \ rightarrow \ mathbb { r } $ and let $ x \ in \ mathbb { r } ^ { n } $ be a local solution to the problem $ \ min _ { x \ in \ mathbb { r } ^ { n } } f ( x ). $ then $ f ' ( x, d ) \ geq 0 $ for every direction $ d \ in \ mathbb { r } ^ { n } $ for which $ f ' ( x, d ) $ exists. moreover, let $ f : \ mathbb { r } ^ { n } \ rightarrow \ mathbb { r } $ be differentiable at $ x ^ { * } \ in \ mathbb { r } ^ { n }. $ if $ x ^ { * } $ is a local minimum of $ f $, then $ \ nabla f ( x ^ { * } ) = 0. $ a simple application involving the dirichlet problem is also given.
|
arxiv:1903.10177
|
we present hydrodynamic and magnetohydrodynamic ( mhd ) simulations of sub galactic regions including photoionising and supernova feedack. we aim to improve the initial conditions of our region extraction models by including an initial population of stars. we also investigate the reliability of extracting regions in simulations, and show that with a good choice of region, results are comparable with using a larger region for the duration of our simulations. simulations of star formation on molecular cloud scales typically start with a turbulent cloud of gas, from which stars form and then undergo feedback. in reality, a typical cloud or region within a galaxy may already include, or reside near some population of stars containing massive stars undergoing feedback. we find the main role of a prior population is triggering star formation, and contributing to gas dynamics. early time supernova from the initial population are important in triggering new star formation and driving gas motions on larger scales above 100 pc, whilst the ionising feedback contribution from the initial population has less impact, since many members of the initial population have cleared out gas around them in the prior model. in terms of overall star formation rates though, the initial population has a relatively small effect, and the feedback does not for example suppress subsequent star formation. we find that mhd has a relatively larger impact than initial conditions, reducing the star formation rate by a factor of 3 at later times.
|
arxiv:2304.06659
|
given a topological ring $ r $, we study semitopological $ r $ - modules, construct their completions, bohr and borno modifications. for every topological space $ x $, we construct the free ( semi ) topological $ r $ - module over $ x $ and prove that for a $ k $ - space $ x $ its free semitopological $ r $ - module is a topological $ r $ - module. also we construct a tychonoff space $ x $ whose free semitopological $ r $ - module is not a topological $ r $ - module.
|
arxiv:2104.06713
|
synchronizability of stable, output - coupled, identical, time - varying linear systems is studied. it is shown that if the observability grammian satisfies a persistence of excitation condition, then there exists a bounded, time - varying linear feedback law that yields exponential synchronization for all fixed, asymmetrical interconnections with connected graphs. also, a weaker condition on the grammian is given for asymptotic synchronization. no assumption is made on the strength of coupling. moreover, related to the main problem, a particular array of output - coupled systems that is pertinent to much - studied consensus problems is investigated. in this array, the individual systems are integrators with identical, time - varying, symmetric positive semi - definite output matrices. trajectories of this array are shown to stay bounded using a time - invariant, quadratic lyapunov function. also, sufficient conditions on output matrix for synchronization are provided. all of the results in the paper are generated for both continuous time and discrete time.
|
arxiv:0811.3496
|
the questions of what represents space - time in gr, the status of gravitational energy, the substantivalist - relationalist issue, and the ( non ) exceptional status of gravity are interrelated. if space - time has energy - momentum, then space - time is substantival. two extant ways to avoid the substantivalist conclusion deny that the energy - bearing metric is part of space - time or deny that gravitational energy exists. feynman linked doubts about gravitational energy to gr - exceptionalism ; particle physics egalitarianism encourages realism about gravitational energy. this essay proposes a third view, involving a particle physics - inspired non - perturbative split that characterizes space - time with a constant background _ matrix _ ( not a metric ), avoiding the inference from gravitational energy to substantivalism : space - time is ( m, eta ), where eta = diag ( - 1, 1, 1, 1 ) is a spatio - temporally constant numerical signature matrix ( already used in gr with spinors ). the gravitational potential, bearing any gravitational energy, is g _ ( munu ) ( x ) - eta ( up to field redefinitions ), an _ affine _ geometric object with a tensorial lie derivative and a vanishing covariant derivative. this non - perturbative split permits strong fields, arbitrary coordinates, and arbitrary topology, and hence is pure gr by almost any standard. this razor - thin background, unlike more familiar ones, involves no extra gauge freedom and so lacks their obscurities and carpet lump - moving. after a discussion of curiel ' s gr exceptionalist rejection of energy conservation, the two traditional objections to pseudotensors, coordinate dependence and nonuniqueness, are explored. both objections are inconclusive and getting weaker. a literal interpretation of noether ' s theorem ( infinitely many energies ) largely answers schroedinger ' s false - negative coordinate dependence problem. bauer ' s nonuniqueness ( false positive ) objection has several answers.
|
arxiv:2208.05946
|
this article analyses geometric constructions by origami when up to $ n $ simultaneous folds may be done at each step. it shows that any arbitrary angle can be $ m $ - sected if the largest prime factor of $ m $ is $ p \ le n + 2 $. also, the regular $ m $ - gon can be constructed if the largest prime factor of $ \ phi ( m ) $ is $ q \ le n + 2 $, where $ \ phi $ is euler ' s totient function.
|
arxiv:1902.01649
|
as in an acoustic black hole where the fluid is moving faster than the speed of sound and where the sound waves are swept along, in an alfven black hole the plasma is moving faster than the alfven velocity, with the alfven waves swept along and eliminated as the cause of the magneto hydrodynamic instabilities. to realize an alfven black hole, it is proposed to bring a plasma into rapid rotation by radially arranged lumped parameter transmission lines intersecting the plasma under an oblique angle. the rotating plasma slides frictionless over magnetic mirror fields directed towards the rotating plasma, with the mirror fields generated by magnetic solenoids positioned at the end of each transmission line. it is then shown that, with this configuration one can realize a thermonuclear dynamo, which also can serve as the analogue of a magnetar.
|
arxiv:0802.3406
|
we consider real random walks with finite variance. we prove an optimal integrability result for the diffusively rescaled maximum, when the walk or its bridge is conditioned to stay positive, or to avoid zero. as an application, we prove tightness under diffusive rescaling for general pinning and wetting models based on random walks.
|
arxiv:1805.10272
|
we study a model of multiple - field dbi inflation leading to mixed form of primordial non - gaussianity, including equilateral and local bispectrum shapes. we present a general formalism based on the hamilton - jacobi approach, allowing us to go beyond slow - roll, combining the three - point function for the fields at hubble - exit with the non - linear evolution of super - hubble scales. we are able to obtain analytic results by taking a separable ansatz for the hubble rate. we find general expressions for both the equilateral and local type non - gaussianity parameter fnl. the equilateral non - gaussianity includes the usual enhancement for small sound speeds, but multiplied by an analytic factor which can lead to a suppression. we illustrate our results with two scenarios. in the first model, previously found to have detectable local non - gaussianity, we find that the equilateral signal is not sufficiently suppressed to evade current observational bounds. in our second scenario we construct a model which exhibits both a detectable equilateral fnl and a negative local fnl.
|
arxiv:1303.3975
|
more readily than they could participate in hunter - gatherer activities. with this increase in population and availability of labor came an increase in labor specialization. what triggered the progression from early neolithic villages to the first cities, such as uruk, and the first civilizations, such as sumer, is not specifically known ; however, the emergence of increasingly hierarchical social structures and specialized labor, of trade and war among adjacent cultures, and the need for collective action to overcome environmental challenges such as irrigation, are all thought to have played a role. the invention of writing led to the spread of cultural knowledge and became the basis for history, libraries, schools, and scientific research. continuing improvements led to the furnace and bellows and provided, for the first time, the ability to smelt and forge gold, copper, silver, and lead – native metals found in relatively pure form in nature. the advantages of copper tools over stone, bone and wooden tools were quickly apparent to early humans, and native copper was probably used from near the beginning of neolithic times ( about 10 kya ). native copper does not naturally occur in large amounts, but copper ores are quite common and some of them produce metal easily when burned in wood or charcoal fires. eventually, the working of metals led to the discovery of alloys such as bronze and brass ( about 4, 000 bce ). the first use of iron alloys such as steel dates to around 1, 800 bce. = = = ancient = = = after harnessing fire, humans discovered other forms of energy. the earliest known use of wind power is the sailing ship ; the earliest record of a ship under sail is that of a nile boat dating to around 7, 000 bce. from prehistoric times, egyptians likely used the power of the annual flooding of the nile to irrigate their lands, gradually learning to regulate much of it through purposely built irrigation channels and " catch " basins. the ancient sumerians in mesopotamia used a complex system of canals and levees to divert water from the tigris and euphrates rivers for irrigation. archaeologists estimate that the wheel was invented independently and concurrently in mesopotamia ( in present - day iraq ), the northern caucasus ( maykop culture ), and central europe. time estimates range from 5, 500 to 3, 000 bce with most experts putting it closer to 4, 000 bce. the oldest artifacts with drawings depicting wheeled carts date from about 3, 500 bce. more recently, the oldest - known wooden wheel in the world as of 2024 was found in the ljubljana marsh of slovenia
|
https://en.wikipedia.org/wiki/Technology
|
we present a general - purpose method to train markov chain monte carlo kernels, parameterized by deep neural networks, that converge and mix quickly to their target distribution. our method generalizes hamiltonian monte carlo and is trained to maximize expected squared jumped distance, a proxy for mixing speed. we demonstrate large empirical gains on a collection of simple but challenging distributions, for instance achieving a 106x improvement in effective sample size in one case, and mixing when standard hmc makes no measurable progress in a second. finally, we show quantitative and qualitative gains on a real - world task : latent - variable generative modeling. we release an open source tensorflow implementation of the algorithm.
|
arxiv:1711.09268
|
the goal of this paper is to define fermionic fields on causal set. this is done by the use of holonomies to define vierbines, and then defining spinor fields by taking advantage of the leftover degrees of freedom of holonomies plus additional scalar fields. grassmann nature is being enforced by allowing measure to take both positive and negative values, and also by introducing a vector space to have both commutting dot product and anticommutting wedge product.
|
arxiv:0808.2956
|
the fundamental unit of $ \ z [ \ sqrt { n } ] $ for square - free $ n = 5 mod 8 $ is either $ \ epsilon $ or $ \ epsilon ^ 3 $ where $ \ epsilon $ denotes the fundamental unit of the maximal order of $ \ q ( \ sqrt { n } ) $. we give infinitely many examples for each case.
|
arxiv:math/0608741
|
in this paper we consider space - time codes where the code - words are restricted to either real or quaternion matrices. we prove two separate diversity - multiplexing gain trade - off ( dmt ) upper bounds for such codes and provide a criterion for a lattice code to achieve these upper bounds. we also point out that lattice codes based on q - central division algebras satisfy this optimality criterion. as a corollary this result provides a dmt classification for all q - central division algebra codes that are based on standard embeddings.
|
arxiv:1801.02913
|
a seminal theorem due to weyl states that if ( a _ n ) is any sequence of distinct integers, then, for almost every real number x, the sequence ( a _ n x ) is uniformly distributed modulo one. in particular, for almost every x in the unit interval, the sequence ( a _ n x ) is uniformly distributed modulo one for every computable sequence ( a _ n ) of distinct integers. call such an x " ud random ". here it is shown that every schnorr random real is ud random, but there are kurtz random reals that are not ud random. on the other hand, weyl ' s theorem still holds relative to a particular effectively closed null set, so there are ud random reals that are not kurtz random.
|
arxiv:1203.4126
|
let $ g $ be a finitely generated abelian - by - finite group and $ k $ a field of characteristic $ p \ ge 0 $. the euler class $ [ k _ g ] $ of $ g $ over $ k $ is the class of the trivial $ kg $ - module in the grothendieck group $ g _ 0 ( kg ) $. we show that $ [ k _ g ] $ has finite order if and only if every $ p $ - regular element of $ g $ has infinite centralizer in $ g $. we also give a lower bound for the order of the euler class in terms of suitable finite subgroups of $ g $. this lower bound is derived from a more general result on finite - dimensional representations of smash products of hopf algebras.
|
arxiv:math/0112129
|
we approach the problem of linear network coding for multicast networks from different perspectives. we introduce the notion of the coding points of a network, which are edges of the network where messages combine and coding occurs. we give an integer linear program that leads to choices of paths through the network that minimize the number of coding points. we introduce the code graph of a network, a simplified directed graph that maintains the information essential to understanding the coding properties of the network. one of the main problems in network coding is to understand when the capacity of a multicast network is achieved with linear network coding over a finite field of size q. we explain how this problem can be interpreted in terms of rational points on certain algebraic varieties.
|
arxiv:1701.05944
|
a system of boundary - domain integral equations is derived from the mixed ( dirichlet - neumann ) boundary value problem for the diffusion equation in inhomogeneous media defined on an unbounded domain. boundary - domain integral equations are formulated in terms of parametrix - based potential type integral operators defined on the boundary and the domain. mapping properties of parametrix - based potentials on weighted sobolev spaces are analysed. equivalence between the original boundary value problem and the system of bdies is shown. uniqueness of solution of the bdies is proved using fredholm alternative and compactness arguments adapted to weigthed sobolev spaces.
|
arxiv:2002.07663
|
at present, optical anapole resonances in nanostructures have attracted increasing attention due to the strong field confinement and substantially suppressed scattering. this study provides the results of three - dimensional finite - difference time - domain simulations exhibiting the possibility of the anapole state in high refractive index dielectric nanohole array metasurfaces having different profiles of the holes ( square, hexagon, and octagon ). behavior of the effective optical kerr nonlinearity of the metasurfaces in the vicinity of the anapole state is investigated. depending on the geometry, the absolute value of the effective nonlinear kerr coefficient of the metasurface may be up to three orders of magnitude greater than that of the unstructured film. a square transverse section of the nanohole is preferable for the optical kerr effect in the holey metasurfaces. the effect of the random rotation of the square holes representing the metasurface irregularity on the optical nonlinearity is examined. as a result, the dielectric nanohole array metasurfaces display a concrete possibility to have the anapole state with large enhancement of the optical nonlinearity.
|
arxiv:2302.01688
|
fractional calculus has been proved to be very effective in representing the visco - elastic relaxation response of materials with memory such as polymers. moreover, in modelling the temperature dependency of the material functions in thermo - visco - elasticity, the standard time - temperature superposition principle is known to be ineffective in most of the cases ( thermo - rehological complexity ). in this work, a novel finite element formulation and numerical implementation is proposed for the simulation of transient thermal analysis in thermo - rehologically complex materials. the parameters of the visco - elastic fractional constitutive law are assumed to be temperature dependent functions and an internal history variable is introduced to track the changes in temperature which are responsible for the phase transition of the material. the numerical approximation of the fractional derivative is employed via the so called gr \ " unwald - letnikov approximation. the proposed model is used to numerically solve some test cases related to relaxation and creep tests conducted on a real polymer ( etylene vynil acetate ), which is used as the major encapsulant of solar cells in photovoltaics.
|
arxiv:2107.08796
|
we study the arithmetic analogue of maximal functions on diagonal hypersurfaces. this paper is a natural step following the papers of \ cite { magyar _ dyadic }, \ cite { magyar _ ergodic } and \ cite { msw }. we combine more precise knowledge of oscillatory integrals and exponential sums to generalize the asymptotic formula in waring ' s problem to an approximation formula for the fourier transform of the solution set of lattice points on hypersurfaces arising in waring ' s problem and apply this result to arithmetic maximal functions and ergodic averages. in sufficiently large dimensions, the approximation formula, $ \ ell ^ 2 $ - maximal theorems and ergodic theorems were previously known. our contribution is in reducing the dimensional constraint in the approximation formula using recent bounds of wooley, and improving the range of $ \ ell ^ p $ spaces in the maximal and ergodic theorems. we also conjecture the expected range of spaces.
|
arxiv:1310.7904
|
interfering electrons in a mesoscopic ring are irradiated with both classical and nonclassical microwaves. the average intensity of the charges is calculated as a function of time and it is found that it depends on the nature of the irradiating electromagnetic field. for various quantum states of the microwaves, the electron autocorrelation function is calculated and it shows that the quantum noise of the external field affects the interference of the charges. two - mode entangled microwaves are also considered and the results are compared with those of the corresponding separable state. in both cases, the results depend on whether the ratio of the two frequencies is rational or irrational.
|
arxiv:cond-mat/0209555
|
in this paper we continue the study of triangular matrix categories $ \ mathbf { \ lambda } = \ left [ \ begin { smallmatrix } \ mathcal { t } & 0 \ \ m & \ mathcal { u } \ end { smallmatrix } \ right ] $ initiated in [ 21 ]. first, given an additive category $ \ mathcal { c } $ and an ideal $ \ mathcal { i } _ { \ mathcal { b } } $ in $ \ mathcal { c } $, we prove a well known result that there is a canonical recollement $ \ xymatrix { \ mathrm { mod } ( \ mathcal { c } / \ mathcal { i } _ { \ mathcal { b } } ) \ ar [ r ] _ { } & \ mathrm { mod } ( \ mathcal { c } ) \ ar [ r ] _ { } \ ar @ < - 1ex > [ l ] _ { } \ ar @ < 1ex > [ l ] _ { } & \ mathrm { mod } ( \ mathcal { b } ) \ ar @ < - 1ex > [ l ] _ { } \ ar @ < 1ex > [ l ] _ { } } $. we show that given a recollement between functor categories we can induce a new recollement between triangular matrix categories, this is a generalization of a result given by chen and zheng in [ 11, theorem 4. 4 ]. in the case of dualizing $ k $ - varieties we can restrict the recollement we obtained to the categories of finitely presented functors. given a dualizing variety $ \ mathcal { c } $, we describe the maps category of $ \ mathrm { mod } ( \ mathcal { c } ) $ as modules over a triangular matrix category and we study its auslander - reiten sequences and contravariantly finite subcategories, in particular we generalize several results from [ 24 ]. finally, we prove a generalization of a result due to { smal \ o } ( [ 35, theorem 2. 1 ] ), which give us a way of construct functorially finite subcategories in the category $ \ mathrm { mod } \ big ( \ left [ \ begin { smallmatrix } \ mathcal { t } & 0 \ \ m & \ mathcal { u } \ end { smallmatrix } \ right
|
arxiv:1903.03926
|
in this letter, we study the on - demand uav - bs placement problem for arbitrarily distributed users. this uav - bs placement problem is modeled as a knapsack - like problem, which is np - complete. we propose a density - aware placement algorithm to maximize the number of covered users subject to the constraint of the minimum required data rates per user. simulations are conducted to evaluate the performance of the proposed algorithm in a real environment with different user densities. our numerical results indicate that for various user densities our proposed solution can service more users with guaranteed data rates compared to the existing method, while reducing the transmit power by 29 %.
|
arxiv:1904.10881
|
we show that the momentum flexibility of inelastic x - ray scattering may be exploited to invert its loss function, alowing real time imaging of density disturbances in a medium. we show the disturbance arising from a point source in liquid water, with a resolution of 41. 3 attoseconds ( $ 4. 13 \ times 10 ^ { - 17 } $ sec ) and 1. 27 $ \ aa $ ( $ 1. 27 \ times 10 ^ { - 8 } $ cm ). this result is used to determine the structure of the electron cloud around a photoexcited molecule in solution, as well as the wake generated in water by a 9 mev gold ion. we draw an analogy with pump - probe techniques and suggest that energy - loss scattering may be applied more generally to the study of attosecond phenomena.
|
arxiv:cond-mat/0311373
|
we determine the ads exchange diagrams needed for the computation of 4 - - point functions of chiral primary operators in the scft _ 2 dual to the d = 6 n = 4b supergravity on the ads _ 3 \ times s ^ 3 background and compute the corresponding cubic couplings. we also address the issue of consistent truncation.
|
arxiv:hep-th/0007061
|
single crystals of flux - grown tetragonal gdfe4al8 were characterized by thermodynamic, transport, and x - ray resonant magnetic scattering measurements. in addition to antiferromagnetic order at tn ~ 155 k, two low - temperature transitions at t1 ~ 21 k and t2 ~ 27 k were identified. the fe moments order at tn with an incommensurate propagation vector ( tau, tau, 0 ) with tau varying between 0. 06 and 0. 14 as a function of temperature, and maintain this order over the entire t < tn range. the gd 4f moments order below t2 with a ferromagnetic component mainly out of plane. below t1, the ferromagnetic components are confined to the crystallographic plane. remarkably, at low temperatures the fe moments maintain the same modulation as at high temperatures, but the gd 4f moments apparently do not follow this modulation. the magnetic phase diagrams for fields applied in [ 110 ] and [ 001 ] direction are presented and possible magnetic structures are discussed.
|
arxiv:cond-mat/0506007
|
despite the continued research and progress in building secure systems, android applications continue to be ridden with vulnerabilities, necessitating effective detection methods. current strategies involving static and dynamic analysis tools come with limitations like overwhelming number of false positives and limited scope of analysis which make either difficult to adopt. over the past years, machine learning based approaches have been extensively explored for vulnerability detection, but its real - world applicability is constrained by data requirements and feature engineering challenges. large language models ( llms ), with their vast parameters, have shown tremendous potential in understanding semnatics in human as well as programming languages. we dive into the efficacy of llms for detecting vulnerabilities in the context of android security. we focus on building an ai - driven workflow to assist developers in identifying and rectifying vulnerabilities. our experiments show that llms outperform our expectations in finding issues within applications correctly flagging insecure apps in 91. 67 % of cases in the ghera benchmark. we use inferences from our experiments towards building a robust and actionable vulnerability detection system and demonstrate its effectiveness. our experiments also shed light on how different various simple configurations can affect the true positive ( tp ) and false positive ( fp ) rates.
|
arxiv:2401.01269
|
the purpose of this paper is to study the exceptional eigenvalues of the asymmetric quantum rabi models ( aqrm ), specifically, to determine the degeneracy of their eigenstates. here, the hamiltonian $ h ^ { \ epsilon } _ { \ text { rabi } } $ of the aqrm is defined by adding the fluctuation term $ \ epsilon \ sigma _ x $, with $ \ sigma _ x $ being the pauli matrix, to the hamiltonian of the quantum rabi model, breaking its $ \ mathbb { z } _ { 2 } $ - symmetry. the spectrum of $ h ^ { \ epsilon } _ { \ text { rabi } } $ contains a set of exceptional eigenvalues, considered to be remains of the eigenvalues of the uncoupled bosonic mode, which are further classified in two types : juddian, associated with polynomial eigensolutions, and non - juddian exceptional. we explicitly describe the constraint relations for allowing the model to have exceptional eigenvalues. by studying these relations we obtain the proof of the conjecture on constraint polynomials previously proposed by the third author. in fact, we prove that the spectrum of the aqrm possesses degeneracies if and only if the parameter $ \ epsilon $ is a half - integer. moreover, we show that non - juddian exceptional eigenvalues do not contribute any degeneracy and we characterize exceptional eigenvalues by representations of $ \ mathfrak { sl } _ 2 $. upon these results, we draw the whole picture of the spectrum of the aqrm. furthermore, generating functions of constraint polynomials from the viewpoint of confluent heun equations are also discussed.
|
arxiv:1712.04152
|
skin cancer ( sc ) stands out as one of the most life - threatening forms of cancer, with its danger amplified if not diagnosed and treated promptly. early intervention is critical, as it allows for more effective treatment approaches. in recent years, deep learning ( dl ) has emerged as a powerful tool in the early detection and skin cancer diagnosis ( scd ). although the dl seems promising for the diagnosis of skin cancer, still ample scope exists for improving model efficiency and accuracy. this paper proposes a novel approach to skin cancer detection, utilizing optimization techniques in conjunction with pre - trained networks and wavelet transformations. first, normalized images will undergo pre - trained networks such as densenet - 121, inception, xception, and mobilenet to extract hierarchical features from input images. after feature extraction, the feature maps are passed through a discrete wavelet transform ( dwt ) layer to capture low and high - frequency components. then the self - attention module is integrated to learn global dependencies between features and focus on the most relevant parts of the feature maps. the number of neurons and optimization of the weight vectors are performed using three new swarm - based optimization techniques, such as modified gorilla troops optimizer ( mgto ), improved gray wolf optimization ( igwo ), and fox optimization algorithm. evaluation results demonstrate that optimizing weight vectors using optimization algorithms can enhance diagnostic accuracy and make it a highly effective approach for scd. the proposed method demonstrates substantial improvements in accuracy, achieving top rates of 98. 11 % with the mobilenet + wavelet + fox and densenet + wavelet + fox combination on the isic - 2016 dataset and 97. 95 % with the inception + wavelet + mgto combination on the isic - 2017 dataset, which improves accuracy by at least 1 % compared to other methods.
|
arxiv:2412.00472
|
the region of small transverse momentum in q qbar - and gg - initiated processes must be studied in the framework of resummation to account for the large, logarithmically - enhanced contributions to physical observables. in this paper, we will calculate the fixed order next - to - leading order ( nlo ) perturbative total and differential cross - sections for both a standard model ( sm ) scalar higgs boson and the minimal supersymmetric standard model ' s ( mssm ) pseudoscalar higgs boson in the heavy quark effective theory ( hqet ) where the mass of the top quark is taken to be infinite. resummation coefficients b ^ 2 _ g, c ^ 2 _ gg for the total cross - section resummation for the pseudoscalar case are given, as well as c ^ 1 _ gg for the differential cross - section.
|
arxiv:hep-ph/0405219
|
ceramic engineering is the science and technology of creating objects from inorganic, non - metallic materials. this is done either by the action of heat, or at lower temperatures using precipitation reactions from high - purity chemical solutions. the term includes the purification of raw materials, the study and production of the chemical compounds concerned, their formation into components and the study of their structure, composition and properties. ceramic materials may have a crystalline or partly crystalline structure, with long - range order on atomic scale. glass - ceramics may have an amorphous or glassy structure, with limited or short - range atomic order. they are either formed from a molten mass that solidifies on cooling, formed and matured by the action of heat, or chemically synthesized at low temperatures using, for example, hydrothermal or sol - gel synthesis. the special character of ceramic materials gives rise to many applications in materials engineering, electrical engineering, chemical engineering and mechanical engineering. as ceramics are heat resistant, they can be used for many tasks for which materials like metal and polymers are unsuitable. ceramic materials are used in a wide range of industries, including mining, aerospace, medicine, refinery, food and chemical industries, packaging science, electronics, industrial and transmission electricity, and guided lightwave transmission. = = history = = the word " ceramic " is derived from the greek word κεραμικος ( keramikos ) meaning pottery. it is related to the older indo - european language root " to burn ". " ceramic " may be used as a noun in the singular to refer to a ceramic material or the product of ceramic manufacture, or as an adjective. ceramics is the making of things out of ceramic materials. ceramic engineering, like many sciences, evolved from a different discipline by today ' s standards. materials science engineering is grouped with ceramics engineering to this day. abraham darby first used coke in 1709 in shropshire, england, to improve the yield of a smelting process. coke is now widely used to produce carbide ceramics. potter josiah wedgwood opened the first modern ceramics factory in stoke - on - trent, england, in 1759. austrian chemist carl josef bayer, working for the textile industry in russia, developed a process to separate alumina from bauxite ore in 1888. the bayer process is still used to purify alumina for the ceramic and aluminium industries. brothers pierre and jacques curie discovered piezoelectricity in rochelle salt c. 1880. piezoelectricity is one of the key properties of electrocera
|
https://en.wikipedia.org/wiki/Ceramic_engineering
|
exceptional points ( eps ) are ubiquitous in non - hermitian systems, and represent the complex counterpart of critical points. by driving a system through a critical point at finite rate induces defects, described by the kibble - zurek mechanism, which finds applications in diverse fields of physics. here we generalize this to a ramp across an ep. we find that adiabatic time evolution brings the system into an eigenstate of the final non - hermitian hamiltonian and demonstrate that for a variety of drives through an ep, the defect density scales as $ \ tau ^ { - ( d + z ) \ nu / ( z \ nu + 1 ) } $ in terms of the usual critical exponents and $ 1 / \ tau $ the speed of the drive. defect production is suppressed compared to the conventional hermitian case as the defect state can decay back to the ground state close to the ep. we provide a physical picture for the studied dynamics through a mapping onto a lindblad master equation with an additionally imposed continuous measurement.
|
arxiv:1812.08668
|
there are two halves to rl systems : experience collection time and policy learning time. for a large number of samples in rollouts, experience collection time is the major bottleneck. thus, it is necessary to speed up the rollout generation time with multi - process architecture support. our work, dubbed wall - e, utilizes multiple rollout samplers running in parallel to rapidly generate experience. due to our parallel samplers, we experience not only faster convergence times, but also higher average reward thresholds. for example, on the mujoco halfcheetah - v2 task, with $ n = 10 $ parallel sampler processes, we are able to achieve much higher average return than those from using only a single process architecture.
|
arxiv:1901.06086
|
ad literacy, humor fight against consumer lust. ", current, archived from the original on february 13, 2005 " pbs goes for mental engineering on super bowl sunday. ", current, january 28, 2002, archived from the original on february 13, 2005 reid day, catherine ( september 2001 ), " one cultural creative ' s journey through the between. ", edge news lambert, brian ( november 12, 2000 ), " ad nauseam : with healthy skepticism, st. paul ' s mental engineering bites the advertising hand that feeds most of tv programming. ", saint paul pioneer press st. anthony, neal ( october 3, 2005 ), " neal st. anthony : deconstructing advertisements ", star tribune = = external links = = mental engineering official website mental engineering at imdb
|
https://en.wikipedia.org/wiki/Mental_Engineering
|
300km. also included are a wide range of equipment, material, and technologies, most of which have uses other than for missiles capable of delivering wmd. while still agreeing to exercise restraint, partners have greater flexibility in the treatment of category ii transfer applications. the mtcr guidelines specifically state that the regime is “ not designed to impede national space programs or international cooperation in such programs as long as such programs could not contribute to delivery systems for weapons of mass destruction. ” mtcr partners are careful with satellite - launched vehicle slv equipment and technology transfers, however, since the technology used in an slv is virtually identical to that used in a ballistic missile, which poses genuine potential for missile proliferation. = = history = = the missile technology control regime ( mtcr ) was established in april 1987 by the g7 countries : canada, france, germany, italy, japan, the united kingdom, and the united states. it was created to curb the spread of unmanned delivery systems for nuclear weapons, specifically systems which can carry a payload of 500 kilograms ( 1, 100 lb ) for 300 kilometres ( 190 mi ). the mtcr applies to exports to members and non - members. an aide - memoire attached to the agreement says that it does not supersede prior agreements, which nato members say allows the supply of category 1 systems between nato members. an example is the export by the united states of trident missiles to the united kingdom for nuclear - weapons delivery. at the annual meeting in oslo from 29 june to 2 july 1992, chaired by sten lundbo, it was agreed to expand the mtcr ' s scope to include nonproliferation of unmanned aerial vehicles ( uavs ) for weapons of mass destruction. prohibited materials are divided into two categories, which are outlined in the mtcr equipment, software, and technology annex. thirty - five nations are members, with india joining on 27 june 2016. according to the arms control association, the mtcr has been successful in helping to slow ( or stop ) several ballistic missile programs : " argentina, egypt, and iraq abandoned their joint condor ii ballistic missile program. brazil and south africa also shelved or eliminated missile or space launch vehicle programs. some former warsaw pact countries, such as poland and the czech republic, destroyed their ballistic missiles, in part, to better their chances of joining mtcr. " in october 1994, the mtcr member states established a " no undercut " policy : if one member denies the sale of technology to another country, all members must do likewise. china originally
|
https://en.wikipedia.org/wiki/Missile_Technology_Control_Regime
|
we study $ q $ - pushtasep, a discrete time interacting particle system whose distribution is related to the $ q $ - whittaker measure. we prove a uniform in $ n $ lower tail bound on the fluctuation scale for the location $ x _ n ( n ) $ of the right - most particle at time $ n $ when started from step initial condition. our argument relies on a map from the $ q $ - whittaker measure to a model of periodic last passage percolation ( lpp ) with geometric weights in an infinite strip that was recently established in [ arxiv : 2106. 11922 ]. by a path routing argument we bound the passage time in the periodic environment in terms of an infinite sum of independent passage times for standard lpp on $ n \ times n $ squares with geometric weights whose parameters decay geometrically. to prove our tail bound result we combine this reduction with a concentration inequality, and a crucial new technical result - - lower tail bounds on $ n \ times n $ last passage times uniformly over all $ n \ in \ mathbb n $ and all the geometric parameters in $ ( 0, 1 ) $. this technical result uses widom ' s trick [ arxiv : math / 0108008 ] and an adaptation of an idea of ledoux introduced for the gue [ led05a ] to reduce the uniform lower tail bound to uniform asymptotics for very high moments, up to order $ n $, of the meixner ensemble. this we accomplish by first obtaining sharp uniform estimates for factorial moments of the meixner ensemble from an explicit combinatorial formula of ledoux [ led05b ], and translating them to polynomial bounds via a further careful analysis and delicate cancellation.
|
arxiv:2212.06806
|
predicting the properties of a molecule from its structure is a challenging task. recently, deep learning methods have improved the state of the art for this task because of their ability to learn useful features from the given data. by treating molecule structure as graphs, where atoms and bonds are modeled as nodes and edges, graph neural networks ( gnns ) have been widely used to predict molecular properties. however, the design and development of gnns for a given data set rely on labor - intensive design and tuning of the network architectures. neural architecture search ( nas ) is a promising approach to discover high - performing neural network architectures automatically. to that end, we develop an nas approach to automate the design and development of gnns for molecular property prediction. specifically, we focus on automated development of message - passing neural networks ( mpnns ) to predict the molecular properties of small molecules in quantum mechanics and physical chemistry data sets from the moleculenet benchmark. we demonstrate the superiority of the automatically discovered mpnns by comparing them with manually designed gnns from the moleculenet benchmark. we study the relative importance of the choices in the mpnn search space, demonstrating that customizing the architecture is critical to enhancing performance in molecular property prediction and that the proposed approach can perform customization automatically with minimal manual effort.
|
arxiv:2008.12187
|
ai is increasingly being used in the public sector, including public security. in this context, the use of ai - powered remote biometric identification ( rbi ) systems is a much - discussed technology. rbi systems are used to identify criminal activity in public spaces, but are criticised for inheriting biases and violating fundamental human rights. it is therefore important to ensure that such systems are developed in the public interest, which means that any technology that is deployed for public use needs to be scrutinised. while there is a consensus among business leaders, policymakers and scientists that ai must be developed in an ethical and trustworthy manner, scholars have argued that ethical guidelines do not guarantee ethical ai, but rather prevent stronger regulation of ai. as a possible counterweight, public opinion can have a decisive influence on policymakers to establish boundaries and conditions under which ai systems should be used - - if at all. however, we know little about the conditions that lead to regulatory demand for ai systems. in this study, we focus on the role of trust in ai as well as trust in law enforcement as potential factors that may lead to demands for regulation of ai technology. in addition, we explore the mediating effects of discrimination perceptions regarding rbi. we test the effects on four different use cases of rbi varying the temporal aspect ( real - time vs. post hoc analysis ) and purpose of use ( persecution of criminals vs. safeguarding public events ) in a survey among german citizens. we found that german citizens do not differentiate between the different modes of application in terms of their demand for rbi regulation. furthermore, we show that perceptions of discrimination lead to a demand for stronger regulation, while trust in ai and trust in law enforcement lead to opposite effects in terms of demand for a ban on rbi systems.
|
arxiv:2401.13605
|
this study proposes a novel precoding scheme for multiuser multiple - input multiple - output ( mimo ) relay systems in the presence of imperfect channel state information ( csi ). the base station ( bs ) and the mimo relay station ( rs ) are both equipped with the same codebook of unitary matrices. according to each element of the codebook, we create a latent precoding matrix pair, namely a bs precoding matrix and an rs precoding matrix. the rs precoding matrix is formed by multiplying the appropriate unitary matrix from the codebook by a power scaling factor. based on the given csi and a block of transmit symbols, the optimum precoding matrix pair, within the class of all possible latent precoding matrix pairs derived from the various unitary matrices, is selected by a suitable selection mechanism for transmission, which is designed to minimize the squared euclidean distance between the pre - estimated received vector and the true transmit symbol vector. we develop a minimum mean square error ( mmse ) design algorithm for the construction of the latent precoding matrix pairs. in the proposed scheme, rather than sending the complete processing matrix, only the index of the unitary matrix and its power scaling factor are sent by the bs to the rs. this significantly reduces the overhead. simulation results show that compared to other recently reported precoding algorithms the proposed precoding scheme is capable of providing improved robustness against the effects of csi estimation errors and multiuser interference.
|
arxiv:1412.5231
|
direct numerical simulation have been carried out for a two dimensional flow in a lid driven cavity at reynolds number 5000 and prandtl number 7 with water as the working fluid. both the side walls of the enclosure are insulated ( i. e. adiabatic boundary condition ), while the bottom plate is at higher temperature and the top wall is at colder temperature. effects of heating of the bottom wall and movement of the top lid have been investigated by conducting numerical simulations at different richardson numbers by varying from low and moderate magnitudes within the limits of boussinesq - approximation. three standard cases has been compared, in the first case heating effects are not taken into account and only the flow due to shear action of the plate is studied. in the second case only the heating effects are taken into account and shear effects are neglected. in the third case effects of both heating and shear action is taken into consideration ( i. e. mixed convection ). drag force on the moving plate is calculated in all the three cases and effect of temperature on the drag force is studied. for running the above simulation a code has been developed which is validated by comparing the results with ghia et al for non - heating case.
|
arxiv:2209.03156
|
kernel methods form a theoretically - grounded, powerful and versatile framework to solve nonlinear problems in signal processing and machine learning. the standard approach relies on the \ emph { kernel trick } to perform pairwise evaluations of a kernel function, leading to scalability issues for large datasets due to its linear and superlinear growth with respect to the training data. recently, we proposed \ emph { no - trick } ( nt ) kernel adaptive filtering ( kaf ) that leverages explicit feature space mappings using data - independent basis with constant complexity. the inner product defined by the feature mapping corresponds to a positive - definite finite - rank kernel that induces a finite - dimensional reproducing kernel hilbert space ( rkhs ). information theoretic learning ( itl ) is a framework where information theory descriptors based on non - parametric estimator of renyi entropy replace conventional second - order statistics for the design of adaptive systems. an rkhs for itl defined on a space of probability density functions simplifies statistical inference for supervised or unsupervised learning. itl criteria take into account the higher - order statistical behavior of the systems and signals as desired. however, this comes at a cost of increased computational complexity. in this paper, we extend the nt kernel concept to itl for improved information extraction from the signal without compromising scalability. specifically, we focus on a family of fast, scalable, and accurate estimators for itl using explicit inner product space ( eips ) kernels. we demonstrate the superior performance of eips - itl estimators and combined nt - kaf using eips - itl cost functions through experiments.
|
arxiv:2001.00265
|
we provide new very simple and compact expressions for the efficient calculation of gravitational lens optical scalars for kerr spacetime which are exact along any null geodesic. these new results are obtained recurring to well known results on geodesic motion that exploit obvious and hidden symmetries of kerr spacetime and contrast with the rather long and cumbersome expressions previously reported in the literature, providing a helpful improvement for the sake of an efficient integration of the geodesic deviation equation on kerr geometry. we also introduce a prescription for the observer frame which captures a new notion of \ emph { center of the black hole } which can be used for any position of the observer, including those near the black hole. we compare the efficient calculation of weak lens optical scalars with the exact equations ; finding an excellent agreement.
|
arxiv:1910.01984
|
a sequence of $ \ { a _ n \ } _ { n \ ge 0 } $ satisfies the briggs inequality if \ begin { align * } a _ n ^ 2 ( a _ n ^ 2 - a _ { n - 1 } a _ { n + 1 } ) > a _ { n - 1 } ^ 2 ( a _ { n + 1 } ^ 2 - a _ na _ { n + 2 } ) \ end { align * } holds for any $ n \ ge 1 $. in this paper we show that both the partition function $ \ { p ( n + n _ 0 ) \ } _ { n \ geq 0 } $ and the overpartition function $ \ { \ overline { p } ( n + \ overline { n } _ 0 ) \ } _ { n \ ge 0 } $ satisfy the briggs inequality for some $ n _ 0 $ and $ \ overline { n } _ { 0 } $. based on chern ' s formula for $ \ eta $ - quotients, we further prove that the $ k $ - regular partition function $ \ { p _ k ( n + n _ { k } ) \ } _ { n \ geq 0 } $ and the $ k $ - regular overpartition function $ \ { \ overline { p } _ k ( n + \ overline { n } _ k ) \ } _ { n \ ge 0 } $ also satisfy the briggs inequality for $ 2 \ le k \ le 9 $ and some $ n _ k, \ overline { n } _ { k } $.
|
arxiv:2408.16185
|
we calculate the formal analytic expansions of certain formal translations in a space of formal iterated logarithmic and exponential variables. the results show how the algebraic structure naturally involves the stirling numbers of the first and second kinds, and certain extensions of these, which appear as expansion coefficients.
|
arxiv:1105.4891
|
we demonstrate that inelastic neutron scattering technique can be used to indirectly detect and measure the macroscopic quantum correlations quantified by both entanglement and discord in a quantum magnetic material, vodpo4. 1d2o. the amount of quantum correlations is obtained 2 by analyzing the neutron scattering data of magnetic excitations in isolated v4 + spin dimers. our quantitative analysis shows that the critical temperature of this material can reach as high as tc = 82. 5 k, where quantum entanglement drops to zero. significantly, quantum discord can even survive at tc = 300 k and may be used in room temperature quantum devices. taking into account the spin - orbit ( so ) coupling, we also predict theoretically that entanglement can be significantly enhanced and the critical temperature tc increases with the strength of spin - orbit coupling.
|
arxiv:1407.0633
|
in this paper we consider cartan - hadamard manifolds ( i. e. simply connected of non - positive sectional curvature ) whose negative ricci curvature grows polynomially at infinity. we show that a number of functional properties, which typically hold when the curvature is bounded, remain true in this setting. these include the characterization of sobolev spaces on manifolds, the so - called cald \ ' eron - zygmund inequalities and the $ l ^ p $ - positivity preserving property, i. e. $ u \ in l ^ p \ \ & \ ( - \ delta + 1 ) u \ ge 0 \ rightarrow u \ ge 0 $. the main tool is a new class of first and second order hardy - type inequalities on cartan - hadamard manifolds with a polynomial upper bound on the curvature. in the last part of the manuscript we prove the $ l ^ p $ - positivity preserving property, $ p \ in [ 1, + \ infty ] $, on manifolds with subquadratic negative part of the ricci curvature. this generalizes an idea of b. g \ " uneysu and gives a new proof of a well - known condition for the stochastic completeness due to p. hsu.
|
arxiv:2105.09024
|
core - collapse supernovae ( ccsne ) emit powerful gravitational waves ( gws ). since gws emitted by a source contain information about the source, observing gws from ccsne may allow us to learn more about ccsns. we study if it is possible to infer the iron core mass from the bounce and early ring - down gw signal. we generate gw signals for a range of stellar models using numerical simulations and apply machine learning to train and classify the signals. we consider an idealized favourable scenario. first, we use rapidly rotating models, which produce stronger gws than slowly rotating models. second, we limit ourselves to models with four different masses, which simplifies the selection process. we show that the classification accuracy does not exceed ~ 70 %, signifying that even in this optimistic scenario, the information contained in the bounce and early ring - down gw signal is not sufficient to precisely probe the iron core mass. this suggests that it may be necessary to incorporate additional information such as the gws from later post - bounce evolution and neutrino observations to accurately measure the iron core mass.
|
arxiv:2209.14542
|
diffusion models have emerged as a formidable tool for training - free conditional generation. however, a key hurdle in inference - time guidance techniques is the need for compute - heavy backpropagation through the diffusion network for estimating the guidance direction. moreover, these techniques often require handcrafted parameter tuning on a case - by - case basis. although some recent works have introduced minimal compute methods for linear inverse problems, a generic lightweight guidance solution to both linear and non - linear guidance problems is still missing. to this end, we propose dreamguider, a method that enables inference - time guidance without compute - heavy backpropagation through the diffusion network. the key idea is to regulate the gradient flow through a time - varying factor. moreover, we propose an empirical guidance scale that works for a wide variety of tasks, hence removing the need for handcrafted parameter tuning. we further introduce an effective lightweight augmentation strategy that significantly boosts the performance during inference - time guidance. we present experiments using dreamguider on multiple tasks across multiple datasets and models to show the effectiveness of the proposed modules. to facilitate further research, we will make the code public after the review process.
|
arxiv:2406.02549
|
with the integration of large - scale renewable energy sources to power systems, many optimization methods have been applied to solve the stochastic / uncertain transmission - constrained unit commitment ( tcuc ) problem. among all methods, two - stage and multi - stage robust optimization - based methods are the most widely adopted ones. in the two - stage methods, nonanticipativity of economic dispatch ( ed ) decisions are not considered. while in multi - stage methods, explicit decision rules ( for example, affine decision rules ) are usually adopted to guarantee nonanticipativity of ed decisions. with explicit decision rules, the computational burden can be heavy and the optimality of the solution is affected. in this paper, a multi - stage robust tcuc formulation with implicit decision rules is proposed, as well as a decomposition framework to solve it. the solutions are proved to be multi - stage robust and nonanticipativity of ed decisions is guaranteed. meanwhile, a computationally efficient time - decoupled solution method for the feasibility check subproblems is also proposed such that the method is suitable for large - scale tcuc problems with uncertain loads / renewable injections. numerical tests are conducted on the ieee 118 - bus system and polish 2383 - bus system. performances of several state - of - the - art methods are compared.
|
arxiv:1810.07447
|
the dispersion relation of an elastic 4 - point amplitude in the forward direction leads to a sum rule that connects the low energy amplitude to the high energy observables. we perform a classification of these sum rules based on massless helicity amplitudes. with this classification, we are able to systematically write down the sum rules for the dimension - 6 operators of the standard model effective field theory ( smeft ), some of which are absent in previous literatures. these sum rules offer distinct insights on the relations between the operator coefficients in the eft and the properties of the full theory that generates them. their applicability goes beyond tree level, and in some cases can be used as a practical method of computing the one loop contributions to low energy observables. they also provide an interesting perspective for understanding the custodial symmetries of the sm higgs and fermion sectors.
|
arxiv:2008.07551
|
we investigate probabilistic transformations of quantum states from a ` source ' set to a ` target ' set of states. such transforms have many applications. they can be used for tasks which include state - dependent cloning or quantum state discrimination, and as interfaces between systems whose information encodings are not related by a unitary transform, such as continuous - variable systems and finite - dimensional systems. in a probabilistic transform, information may be lost or leaked, and we explain the concepts of leak and redundancy. following this, we show how the analysis of probabilistic transforms significantly simplifies for symmetric source and target sets of states. in particular, we give a simple linear program which solves the task of finding optimal transforms, and a method of characterizing the introduced leak and redundancy in information - theoretic terms. using the developed techniques, we analyse a class of transforms which convert coherent states with information encoded in their relative phase to symmetric qubit states. each of these sets of states on their own appears in many well studied quantum information protocols. finally, we suggest an asymptotic realization based on quantum scissors.
|
arxiv:1206.5093
|
we introduce doppler time - of - flight ( d - tof ) rendering, an extension of tof rendering for dynamic scenes, with applications in simulating d - tof cameras. d - tof cameras use high - frequency modulation of illumination and exposure, and measure the doppler frequency shift to compute the radial velocity of dynamic objects. the time - varying scene geometry and high - frequency modulation functions used in such cameras make it challenging to accurately and efficiently simulate their measurements with existing tof rendering algorithms. we overcome these challenges in a twofold manner : to achieve accuracy, we derive path integral expressions for d - tof measurements under global illumination and form unbiased monte carlo estimates of these integrals. to achieve efficiency, we develop a tailored time - path sampling technique that combines antithetic time sampling with correlated path sampling. we show experimentally that our sampling technique achieves up to two orders of magnitude lower variance compared to naive time - path sampling. we provide an open - source simulator that serves as a digital twin for d - tof imaging systems, allowing imaging researchers, for the first time, to investigate the impact of modulation functions, material properties, and global illumination on d - tof imaging performance.
|
arxiv:2309.16163
|
the fundamental vacuum state of quantum fields, related to minkowski space, produces divergent fluctuations that must be suppressed in order to bring reality to the description of physical systems. as a consequence, negative vacuum expectation values of classically positive - defined quantities can appear. this has been addressed in the literature as subvacuum phenomenon. here it is investigated how a scalar charged test particle is affected by the vacuum fluctuations of a massive scalar field in d + 1 spacetime when the background evolves from empty space to a thermal bath, and also when a perfectly reflecting boundary is included. it is shown that when the particle is brought into a thermal bath it gains an amount of energy by means of positive dispersions of its velocity components. the magnitude of this effect is dependent on the temperature and also on the field mass. however, when a reflecting wall is inserted, dispersions can be positive or negative, showing that subvacuum effect happens even in a finite temperature environment. furthermore, a remarkable result is that temperature can even improve negative velocity fluctuations. the magnitude of the residual effects depends on the switching interval of time the system takes to evolve between two states.
|
arxiv:2010.07146
|
we prove a linear inequality between the entropy and entropy dissipation functionals for the linear boltzmann operator ( with a maxwellian equilibrium background ). this provides a positive answer to the analogue of cercignani ' s conjecture for this linear collision operator. our result covers the physically relevant case of hard - spheres interactions as well as maxwellian kernels, both with and without a cut - off assumption. for maxwellian kernels, the proof of the inequality is surprisingly simple and relies on a general estimate of the entropy of the gain operator due to matthes and toscani ( 2012 ) and villani ( 1998 ). for more general kernels, the proof relies on a comparison principle. finally, we also show that in the grazing collision limit our results allow to recover known logarithmic sobolev inequalities.
|
arxiv:1405.0366
|
plasma physics, relativity, solid mechanics, operations research, quantitative finance, information technology and engineering, dynamical systems, bioengineering, environmental engineering, computational engineering, engineering mathematics and statistics, solid - state devices, materials science, electromagnetism, nanoscience, nanotechnology, energy, and optics. = = awards = = there are awards for excellence in engineering physics. for example, princeton university ' s jeffrey o. kephart ' 80 prize is awarded annually to the graduating senior with the best record. since 2002, the german physical society has awarded the georg - simon - ohm - preis for outstanding research in this field. = = see also = = applied physics engineering engineering science and mechanics environmental engineering science index of engineering science and mechanics articles industrial engineering = = notes and references = = = = external links = = " engineering physics at xavier " " the engineering physicist profession " " engineering physicist professional profile " society of engineering science inc. archived 2017 - 08 - 07 at the wayback machine
|
https://en.wikipedia.org/wiki/Engineering_physics
|
the main result of this paper is a construction of solutions to the reverse yang - mills - higgs flow converging in the $ c ^ \ infty $ topology to a critical point. the construction uses only the complex gauge group action, which leads to an algebraic classification of the isomorphism classes of points in the unstable set of a critical point in terms of a filtration of the underlying higgs bundle. analysing the compatibility of this filtration with the harder - narasimhan - seshadri double filtration gives an algebraic criterion for two critical points to be connected by a flow line. as an application, we can use this to construct hecke modifications of higgs bundles via the yang - mills - higgs flow. when the higgs field is zero ( corresponding to the yang - mills flow ), this criterion has a geometric interpretation in terms of secant varieties of the projectivisation of the underlying bundle inside the unstable manifold of a critical point, which gives a precise description of broken and unbroken flow lines connecting two critical points. for non - zero higgs field, at generic critical points the analogous interpretation involves the secant varieties of the spectral curve of the higgs bundle.
|
arxiv:1605.05970
|
wi - fi, running on suitable hardware at close range, can achieve speeds of 9. 6 gbit / s ( gigabit per second ). = = history = = a 1985 ruling by the u. s. federal communications commission released parts of the ism bands for unlicensed use for communications. these frequency bands include the same 2. 4 ghz bands used by equipment such as microwave ovens, and are thus subject to interference. in 1991 in nieuwegein, the ncr corporation and at & t invented the precursor to 802. 11, intended for use in cashier systems, under the name wavelan. ncr ' s vic hayes, who held the chair of ieee 802. 11 for ten years, along with bell labs engineer bruce tuch, approached the institute of electrical and electronics engineers ( ieee ) to create a standard and were involved in designing the initial 802. 11b and 802. 11a specifications within the ieee. they have both been subsequently inducted into the wi - fi now hall of fame. in 1989 in australia, a team of scientists began working on wireless lan technology. a prototype test bed for a wireless local area network ( wlan ) was developed in 1992 by a team of researchers from the radiophysics division of the csiro ( commonwealth scientific and industrial research organisation ) in australia, led by john o ' sullivan. a patent for wi fi was lodged by the csiro in 1992. the first version of the 802. 11 protocol was released in 1997, and provided up to 2 mbit / s link speeds. this was updated in 1999 with 802. 11b to permit 11 mbit / s link speeds. in 1999, the wi - fi alliance formed as a trade association to hold the wi - fi trademark under which most ieee 802. 11 products are sold. the major commercial breakthrough came with apple inc. adopting wi - fi for their ibook series of laptops in 1999. it was the first mass consumer product to offer wi - fi network connectivity, which was then branded by apple as airport. this was in collaboration with the same group that helped create the standard : vic hayes, bruce tuch, cees links, rich mcginn, and others from lucent. in 2000, radiata, a group of australian scientists connected to the csiro, were the first to use the 802. 11a standard on chips connected to a wi - fi network. wi - fi uses a large number of patents held by multiple different organizations. australia, the united states and the
|
https://en.wikipedia.org/wiki/Wi-Fi
|
under a pulled - back approach given in [ 1 ] and firstly presented in [ 2 ], we introduce, in this paper, the concepts of almost contact and normal almost contact finsler structures on the pulled - back bundle. properties of structures partly sasakians are studied. using the hh - curvature tensor of chern connection given in [ 2 ], we obtain some characterizations of horizontally finslerian k - contact structures via the horizontal ricci tensor and the flag curvature.
|
arxiv:1604.05425
|
in recent years, several methods have been proposed for explaining individual predictions of deep learning models, yet there has been little study of how to aggregate these predictions to explain how such models view classes as a whole in text classification tasks. in this work, we propose a method for explaining classes using deep learning models and the integrated gradients feature attribution technique by aggregating explanations of individual examples in text classification to general descriptions of the classes. we demonstrate the approach on web register ( genre ) classification using the xml - r model and the corpus of online registers of english ( core ), finding that the method identifies plausible and discriminative keywords characterizing all but the smallest class.
|
arxiv:2108.13653
|
we analyze random unitary evolution of the qubit within memory kernel approach. we provide sufficient conditions which guarantee that the corresponding memory kernel generates physically legitimate quantum evolution. interestingly, we are able to recover several well known examples and generate new classes of nontrivial qubit evolution. surprisingly, it turns out that quantum evolution with memory kernel generated by our approach gives rise to vanishing non - markovianity measure based on the distinguishability of quantum states.
|
arxiv:1501.05179
|
we present a new, galaxy - halo model of large - scale structure, in which the galaxies entering a given sample are the fundamental objects. haloes attach to galaxies, in contrast to the standard halo model, in which galaxies attach to haloes. the galaxy - halo model pertains mainly to the relationships between the power spectra of galaxies and mass, and their cross - power spectrum. with surprisingly little input, an intuition - aiding approximation to the galaxy - matter cross - correlation coefficient r ( k ) emerges, in terms of the halo mass dispersion. this approximation seems valid to mildly non - linear scales ( k < ~ 3 h / mpc ), allowing measurement of the bias and the matter power spectrum from measurements of the galaxy and galaxy - matter power spectra ( or correlation functions ). this is especially relevant given the recent advances in precision in measurements of the galaxy - matter correlation function from weak gravitational lensing. the galaxy - halo model also addresses the issue of interpreting the galaxy - matter correlation function as an average halo density profile, and provides a simple description of galaxy bias as a function of scale.
|
arxiv:astro-ph/0504161
|
here we extend the concept of blind client - server quantum computation, in which a client with limited quantum power controls the execution of a quantum computation on a powerful server, without revealing any details of the computation. our extension is to introduce a three - node setting in which an oracular quantum computation can be executed blindly. in this blind oracular quantum computation ( boqc ), the oracle ( oscar ) is another node, with limited power, who acts in cooperation with the client ( alice ) to supply quantum information to the server so that the oracle part of the quantum computation can also be executed blindly. we develop tests of this protocol using two - and three - qubit versions of the exact grover algorithm ( i. e., with database sizes $ 4 \ leq n \ leq 8 $ ), obtaining optimal implementations of these algorithms within a gate array scheme and the blinded cluster - state scheme. we discuss the feasibility of executing these protocols in state - of - the - art three - node experiments using nv - diamond electronic and nuclear qubits.
|
arxiv:1902.05534
|
, \, \, \, \ int a ^ { 2 } \, d [ v ' ] \, d [ ( v ^ * ) ' ] \, dx. $ \ smallskip introducing the constraint $ \ int a ^ 2 \, d u \, dx = v $, we also consider later an associated dual eigenvalue problem. from this follows a transport and a kind of eikonal equation.
|
arxiv:2403.05865
|
the goal of this survey is to study the formation and evolution of the milky way halo to deduce its assembly history and the 3d distribution of mass in the milky way. the combination of multi - band photometry, gaia proper motion and parallax data, and radial velocities and the metallicity and elemental abundances obtained from low - resolution spectra of halo giants with 4most, will yield an unprecedented characterisation of the milky way halo and its interface with the thick disc. the survey will produce a volume - and magnitude - limited complete sample of giant stars in the halo. it will cover at least 10, 000 square degrees of high galactic latitude, and measure line - of - sight velocities with a precision of 1 - 2 km / s as well as metallicities to within 0. 2 dex.
|
arxiv:1903.02467
|
mobile devices with rich features can record videos, traffic parameters or air quality readings along user trajectories. although such data may be valuable, users are seldom rewarded for collecting them. emerging digital marketplaces allow owners to advertise their data to interested buyers. we focus on geo - marketplaces, where buyers search data based on geo - tags. such marketplaces present significant challenges. first, if owners upload data with revealed geo - tags, they expose themselves to serious privacy risks. second, owners must be accountable for advertised data, and must not be allowed to subsequently alter geo - tags. third, such a system may be vulnerable to intensive spam activities, where dishonest owners flood the system with fake advertisements. we propose a geo - marketplace that addresses all these concerns. we employ searchable encryption, digital commitments, and blockchain to protect the location privacy of owners while at the same time incorporating accountability and spam - resilience mechanisms. we implement a prototype with two alternative designs that obtain distinct trade - offs between trust assumptions and performance. our experiments on real location data show that one can achieve the above design goals with practical performance and reasonable financial overhead.
|
arxiv:1909.00299
|
recent advances in artificial intelligence ( ai ) offer an opportunity for the adoption of self - driving networks. however, network operators or home - network users still do not have the right tools to exploit these new advancements in ai, since they have to rely on low - level languages to specify network policies. intent - based networking ( ibn ) allows operators to specify high - level policies that dictate how the network should behave without worrying how they are translated into configuration commands in the network devices. however, the existing research proposals for ibn fail to exploit the knowledge and feedback from the network operator to validate or improve the translation of intents. in this paper, we introduce a novel intent - refinement process that uses machine learning and feedback from the operator to translate the operator ' s utterances into network configurations. our refinement process uses a sequence - to - sequence learning model to extract intents from natural language and the feedback from the operator to improve learning. the key insight of our process is an intermediate representation that resembles natural language that is suitable to collect feedback from the operator but is structured enough to facilitate precise translations. our prototype interacts with a network operator using natural language and translates the operator input to the intermediate representation before translating to sdn rules. our experimental results show that our process achieves a correlation coefficient squared ( i. e., r - squared ) of 0. 99 for a dataset with 5000 entries and the operator feedback significantly improves the accuracy of our model.
|
arxiv:2008.05509
|
do large language models ( llms ) have theory of mind? a plethora of papers and benchmarks have been introduced to evaluate if current models have been able to develop this key ability of social intelligence. however, all rely on limited datasets with simple patterns that can potentially lead to problematic blind spots in evaluation and an overestimation of model capabilities. we introduce exploretom, the first framework to allow large - scale generation of diverse and challenging theory of mind data for robust training and evaluation. our approach leverages an a * search over a custom domain - specific language to produce complex story structures and novel, diverse, yet plausible scenarios to stress test the limits of llms. our evaluation reveals that state - of - the - art llms, such as llama - 3. 1 - 70b and gpt - 4o, show accuracies as low as 0 % and 9 % on exploretom - generated data, highlighting the need for more robust theory of mind evaluation. as our generations are a conceptual superset of prior work, fine - tuning on our data yields a 27 - point accuracy improvement on the classic tomi benchmark ( le et al., 2019 ). exploretom also enables uncovering underlying skills and factors missing for models to show theory of mind, such as unreliable state tracking or data imbalances, which may contribute to models ' poor performance on benchmarks.
|
arxiv:2412.12175
|
large language models ( llms ) can perform accurate classification with zero or few examples through in - context learning. we extend this capability to regression with uncertainty estimation using frozen llms ( e. g., gpt - 3. 5, gemini ), enabling bayesian optimization ( bo ) in natural language without explicit model training or feature engineering. we apply this to materials discovery by representing experimental catalyst synthesis and testing procedures as natural language prompts. a key challenge in materials discovery is the need to characterize suboptimal candidates, which slows progress. while bo is effective for navigating large design spaces, standard surrogate models like gaussian processes assume smoothness and continuity, an assumption that fails in highly non - linear domains such as heterogeneous catalysis. our task - agnostic bo workflow overcomes this by operating directly in language space, producing interpretable and actionable predictions without requiring structural or electronic descriptors. on benchmarks like aqueous solubility and oxidative coupling of methane ( ocm ), bo - icl matches or outperforms gaussian processes. in live experiments on the reverse water - gas shift ( rwgs ) reaction, bo - icl identifies near - optimal multi - metallic catalysts within six iterations from a pool of 3, 700 candidates. our method redefines materials representation and accelerates discovery, with broad applications across catalysis, materials science, and ai. code : https : / / github. com / ur - whitelab / bo - icl.
|
arxiv:2304.05341
|
it is a surprising fact that the proportion of integer lattice points visible from the origin is exactly $ \ frac { 6 } { \ pi ^ 2 } $, or approximately 60 percent. hence, approximately 40 percent of the integer lattice is hidden from the origin. since 1971, many have studied a variety of problems involving lattice point visibility, in particular, searching for patterns in that 40 percent of the lattice comprised of invisible points. one such pattern is a square patch, an $ n \ times n $ grid of $ n ^ 2 $ invisible points, which we call a hidden forest. it is known that there exist arbitrarily large hidden forests in the integer lattice. however, the methods up to now involve the chinese remainder theorem ( crt ) on the rows and columns of matrices with prime number entries, and they have only been able to locate hidden forests very far from the origin. for example, using this method the closest known $ 4 \ times 4 $ hidden forest is over 3 quintillion, or $ 3 \ times 10 ^ { 18 } $, units away from the origin. we introduce the concept of quasiprime matrices and utilize a variety of computational and theoretical techniques to find some of the closest known hidden forests to this date. using these new techniques, we find a $ 4 \ times 4 $ hidden forest that is merely 184 million units away from the origin. we conjecture that every hidden forest can be found via the crt - algorithm on a quasiprime matrix.
|
arxiv:1805.03186
|
this paper investigates epidemic control behavioral synchronization for a class of complex networks resulting from spread of epidemic diseases via pinning feedback control strategy. based on the quenched mean field theory, epidemic control synchronization models with inhibition of contact behavior is constructed, combining with the epidemic transmission system and the complex dynamical network carrying extra controllers. by the properties of convex functions and gerschgorin theorem, the epidemic threshold of the model is obtained, and the global stability of disease - free equilibrium is analyzed. for individual ' s infected situation, when epidemic spreads, two types of feedback control strategies depended on the diseases ' information are designed : the one only adds controllers to infected individuals, the other adds controllers both to infected and susceptible ones. and by using lyapunov stability theory, under designed controllers, some criteria that guarantee epidemic control synchronization system achieving behavior synchronization are also derived. several numerical simulations are performed to show the effectiveness of our theoretical results. as far as we know, this is the first work to address the controlling behavioral synchronization induced by epidemic spreading under the pinning feedback mechanism. it is hopeful that we may have more deeper insight into the essence between disease ' s spreading and collective behavior controlling in complex dynamical networks.
|
arxiv:1806.06651
|
cosmological models with an su ( 2 ) yang - mills field are studied. for a specific model with a minimally coupled yang - mills lagrangian, which includes an arbitrary function of the second - order term and a fourth - order term, a corresponding reconstruction program is proposed. it is shown that the model with minimal coupling has no de sitter solutions, for any nontrivial function of the second - order term. to get de sitter solutions, a gravitational model with nonminimally coupled yang - mills fields is then investigated. it is shown that the model with non - minimal coupling has in fact a de sitter solution, even in absence of the cosmological constant term.
|
arxiv:1201.4302
|
the weighted $ k $ - center problem in graphs is a classical facility location problem where we place $ k $ centers on the graph, which minimize the maximum weighted distance of a vertex to its nearest center. we study this problem when the underlying graph is a cactus with $ n $ vertices and present an $ o ( n \ log ^ 2 n ) $ time algorithm for the same. this time complexity improves upon the $ o ( n ^ 2 ) $ time algorithm by ben - moshe et al. [ tcs 2007 ], which is the current state - of - the - art.
|
arxiv:2303.17204
|
let $ v ( k, \ lambda ) $ be the maximum number of vertices of a connected $ k $ - regular graph with second largest eigenvalue at most $ \ lambda $. the alon - boppana theorem implies that $ v ( k, \ lambda ) $ is finite when $ k > \ frac { \ lambda ^ 2 + 4 } { 4 } $. in this paper, we show that for fixed $ \ lambda \ geq1 $, there exists a constant $ c ( \ lambda ) $ such that $ 2k + 2 \ leq v ( k, \ lambda ) \ leq 2k + c ( \ lambda ) $ when $ k > \ frac { \ lambda ^ 2 + 4 } { 4 } $.
|
arxiv:1809.01888
|
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.