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we tackle societal bias in image - text datasets by removing spurious correlations between protected groups and image attributes. traditional methods only target labeled attributes, ignoring biases from unlabeled ones. using text - guided inpainting models, our approach ensures protected group independence from all attributes and mitigates inpainting biases through data filtering. evaluations on multi - label image classification and image captioning tasks show our method effectively reduces bias without compromising performance across various models.
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arxiv:2407.03623
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the optimal allocation of time and energy resources is characterized in a wireless powered communication network ( wpcn ) with non - orthogonal multiple access ( noma ). we consider two different formulations ; in the first one ( max - sum ), the sum - throughput of all users is maximized. in the second one ( max - min ), and targeting fairness among users, we consider maximizing the min - throughput of all users. under the above two formulations, two noma decoding schemes are studied, namely, low complexity decoding ( lcd ) and successive interference cancellation decoding ( sicd ). due to the non - convexity of three of the studied optimization problems, we consider an approximation approach, in which the non - convex optimization problem is approximated by a convex optimization problem, which satisfies all the constraints of the original problem. the approximated convex optimization problem can then be solved iteratively. the results show a trade - off between maximizing the sum throughout and achieving fairness through maximizing the minimum throughput.
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arxiv:1808.00268
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since the length of microblog texts, such as tweets, is strictly limited to 140 characters, traditional information retrieval techniques suffer from the vocabulary mismatch problem severely and cannot yield good performance in the context of microblogosphere. to address this critical challenge, in this paper, we propose a new language modeling approach for microblog retrieval by inferring various types of context information. in particular, we expand the query using knowledge terms derived from freebase so that the expanded one can better reflect users ' search intent. besides, in order to further satisfy users ' real - time information need, we incorporate temporal evidences into the expansion method, which can boost recent tweets in the retrieval results with respect to a given topic. experimental results on two official trec twitter corpora demonstrate the significant superiority of our approach over baseline methods.
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arxiv:1503.03961
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we consider a generic min - max multi - objective bilevel optimization problem with applications in robust machine learning such as representation learning and hyperparameter optimization. we design morbit, a novel single - loop gradient descent - ascent bilevel optimization algorithm, to solve the generic problem and present a novel analysis showing that morbit converges to the first - order stationary point at a rate of $ \ widetilde { \ mathcal { o } } ( n ^ { 1 / 2 } k ^ { - 2 / 5 } ) $ for a class of weakly convex problems with $ n $ objectives upon $ k $ iterations of the algorithm. our analysis utilizes novel results to handle the non - smooth min - max multi - objective setup and to obtain a sublinear dependence in the number of objectives $ n $. experimental results on robust representation learning and robust hyperparameter optimization showcase ( i ) the advantages of considering the min - max multi - objective setup, and ( ii ) convergence properties of the proposed morbit. our code is at https : / / github. com / minimario / morbit.
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arxiv:2203.01924
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currently, deep neural networks ( dnns ) have achieved a great success in various applications. traditional deployment for dnns in the cloud may incur a prohibitively serious delay in transferring input data from the end devices to the cloud. to address this problem, the hybrid computing environments, consisting of the cloud, edge and end devices, are adopted to offload dnn layers by combining the larger layers ( more amount of data ) in the cloud and the smaller layers ( less amount of data ) at the edge and end devices. a key issue in hybrid computing environments is how to minimize the system cost while accomplishing the offloaded layers with their deadline constraints. in this paper, a self - adaptive discrete particle swarm optimization ( pso ) algorithm using the genetic algorithm ( ga ) operators was proposed to reduce the system cost caused by data transmission and layer execution. this approach considers the characteristics of dnns partitioning and layers offloading over the cloud, edge and end devices. the mutation operator and crossover operator of ga were adopted to avert the premature convergence of pso, which distinctly reduces the system cost through enhanced population diversity of pso. the proposed offloading strategy is compared with benchmark solutions, and the results show that our strategy can effectively reduce the cost of offloading for dnn - based applications over the cloud, edge and end devices relative to the benchmarks.
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arxiv:1907.13306
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effect of radiation - reaction force on the dynamics of a charged particle in an intense focused light wave is investigated using the physically appealing hartemann - luhmann equation of motion. it is found that, irrespective of the choice of initial conditions, radiation reaction force causes the charge particle to cross the focal region, thereby enhancing the forward energy gained by the particle from the intense light wave. this result is in sharp contrast to the well known result, derived in the absence of radiation reaction forces, where for certain initial conditions the particle reflects from the high intensity region of the focused light wave, thereby losing forward energy. these results, which are of relevance to the present day direct laser acceleration schemes of charge particle, also agrees with that obtained using the well known landau - lifshitz equation of motion.
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arxiv:2112.08063
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a sequence is nonrepetitive if it does not contain two adjacent identical blocks. the remarkable construction of thue asserts that 3 symbols are enough to build an arbitrarily long nonrepetitive sequence. it is still not settled whether the following extension holds : for every sequence of 3 - element sets $ l _ 1,..., l _ n $ there exists a nonrepetitive sequence $ s _ 1,..., s _ n $ with $ s _ i \ in l _ i $. applying the probabilistic method one can prove that this is true for sufficiently large sets $ l _ i $. we present an elementary proof that sets of size 4 suffice ( confirming the best known bound ). the argument is a simple counting with catalan numbers involved. our approach is inspired by a new algorithmic proof of the lov \ ' { a } sz local lemma due to moser and tardos and its interpretations by fortnow and tao. the presented method has further applications to nonrepetitive games and nonrepetitive colorings of graphs.
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arxiv:1103.3809
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a toy model where a massless, real, scalar field $ \ phi $ in a compact space - time $ { \ cal m } _ 4 \ times { \ cal s } _ 1 $ is coupled to a brane ( parametrized as a $ \ delta $ - function ) through the unique relevant operator $ \ delta ( y ) \ phi ^ 2 ( x, y ) $ is considered. the exact kaluza - klein spectrum of the model is computed for any value of the coupling between field and brane using the burniston - siewert method to solve analytically transcendental equations. the exact kk - spectrum of a model with a brane - localized kinetic term is also computed. weak - and strong - coupling limits are derived, matching or extending mathematically equivalent existing results. for a negative coupling, the would - be zero - mode $ \ psi _ { 0 ^ - } ^ e $ is found to localize into the brane, behaving as an effective four - dimensional field. the 4 - dimensional kk - decomposition of the model once a renormalizable cubic self - interaction $ \ phi ^ 3 ( x, y ) $ is added to the action is derived computing the overlaps between the kk - modes. it is found that the localized would - be zero - mode $ \ psi _ { 0 ^ - } ^ e $ decouples from the massive kk - spectrum in the limit of large brane - to - bulk coupling.
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arxiv:1512.03978
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we consider the presence and evolution of primordial density perturbations in a cosmological model based on a simple ansatz which captures - - by providing a set of effective gravitational field equations - - the strength of the enhanced quantum loop effects that can arise during inflation. after deriving the general equations that perturbations obey, we concentrate on scalar perturbations and show that their evolution is quite different than that of conventional inflationary models but still phenomenologically acceptable. the main reason for this novel evolution is the presence of an oscillating regime after the end of inflation which makes all super - horizon scalar modes oscillate. the same reason allows for a natural and very fast reheating mechanism for the universe.
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arxiv:1006.4834
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in this paper, we calculate the relativistic corrections to the zeeman effect for hydrogen - like atoms based on the generalized uncertainty principle ( gup ). we propose a relativistic gup algebra using the stetsko and tkachuk approximation and incorporate these corrections into the zeeman effect. in the relativistic limit, our results recover previously derived gup corrections as well as the standard lande energy shift expression when gup effects are absent. this work presents a generalized expression that accounts for both relativistic and gup corrections to the zeeman effect.
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arxiv:2410.11965
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in an incineration plant, remote operation from a centralized control room is now possible, but inspection and cleaning of equipment still require a worker to visit the site. when the plant owner reduces the number of workers due to operation costs, it will be standard for a single worker to visit the site. therefore, it is necessary to monitor the location of workers in real - time to detect unexpected human accidents quickly. conventional methods use radio waves, such as wi - fi and bluetooth, but there is little demand for communication equipment in the incineration plant. however, there is not enough demand for communication facilities in the incineration plant. it is too large to bear the cost of installing wireless access points, and bluetooth low energy ( ble ) beacons just for positioning. therefore, we are focusing on magnetism using for indoor positioning method. in addition, the incineration plant has a lot of types of equipment that contains a wide range of magnetized metals, large motors, and generators. we could observe the magnetic peculiarity at each point. based on these assumptions, we have developed a new indoor positioning method at the incineration plant. this paper describes the development of an indoor positioning system for an incineration plant. and we propose three methods for fingerprinting matching : point matching, path matching, and dtw matching. the average positioning errors of these methods are 6. 89 m, 0. 05 m, and 0. 06 m, respectively.
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arxiv:2203.12952
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we investigate the question of whether the spectral metric on the orbit space of a fiber in the disk cotangent bundle of a closed manifold, under the action of the compactly supported hamiltonian diffeomorphism group, is bounded. we utilize wrapped floer cohomology to define the spectral invariant of an admissible lagrangian submanifold within a weinstein domain. we show that the pseudo - metric derived from this spectral invariant is a valid $ ham $ - invariant metric. furthermore, we establish that the spectral metric on the orbit space of an admissible lagrangian is bounded if and only if the wrapped floer cohomology vanishes. consequently, we prove that the lagrangian hofer diameter of the orbit space for any fiber in the disk cotangent bundle of a closed manifold is infinite.
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arxiv:2307.02290
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this paper presents a novel koopman ( composition ) operator representation framework for control systems in reproducing kernel hilbert spaces ( rkhss ) that is free of explicit dictionary or input parametrizations. by establishing fundamental equivalences between different model representations, we are able to close the gap of control system operator learning and infinite - dimensional regression, enabling various empirical estimators and the connection to well - understood learning theory in rkhss under one unified framework. as a consequence, our proposed framework allows for arbitrary accurate finite - rank approximations in infinite - dimensional spaces and leads to finite - dimensional predictors without apriori restrictions to a finite span of functions or inputs. to enable applications to high - dimensional control systems, we improve the scalability of our proposed control koopman operator estimates by utilizing sketching techniques. numerical experiments demonstrate superior prediction accuracy compared to bilinear edmd, especially in high dimensions. finally, we show that our learned models are readily interfaced with linear - parameter - varying techniques for model predictive control.
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arxiv:2405.07312
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we have used the visible integral - field replicable unit spectrograph prototype ( virus - p ), a new integral field spectrograph, to study the spatially and spectrally resolved lyman - alpha emission line structure in the radio galaxy b2 0902 + 34 at z = 3. 4. we observe a halo of lyman - alpha emission with a velocity dispersion of 250 km / s extending to a radius of 50 kpc. a second feature is revealed in a spatially resolved region where the line profile shows blueshifted structure. this may be viewed as either hi absorption at - 450 km / s or secondary emission at - 900 km / s from the primary peak. our new data, in combination with the 21 cm absorption, suggest two important and unexplained discrepancies. first, nowhere in the line profiles of the lyman - alpha halo is the 21 cm absorber population evident. second, the 21 cm absorption redshift is higher than the lyman - alpha emission redshift. in an effort to explain these two traits, we have undertaken the first three dimensional monte carlo simulations of resonant scattering in radio galaxies. though simple, the model produces the features in the lyman - alpha data and predicts the 21 cm properties. to reach agreement between this model and the data, global infall of the hi is strictly necessary. the amount of gas necessary to match the model and data is surprisingly high, > = 10e12 solar masses, an order of magnitude larger than the stellar mass. the collapsing structure and large gas mass lead us to interpret b2 0902 + 34 as a protogiant elliptical galaxy.
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arxiv:0812.1333
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the critical path of internode communication on large - scale systems is composed of multiple components. when a supercomputing application initiates the transfer of a message using a high - level communication routine such as an mpi _ send, the payload of the message traverses multiple software stacks, the i / o subsystem on both the host and target nodes, and network components such as the switch. in this paper, we analyze where, why, and how much time is spent on the critical path of communication by modeling the overall injection overhead and end - to - end latency of a system. we focus our analysis on the performance of small messages since fine - grained communication is becoming increasingly important with the growing trend of an increasing number of cores per node. the analytical models present an accurate and detailed breakdown of time spent in internode communication. we validate the models on arm thunderx2 - based servers connected with mellanox infiniband. this is the first work of this kind on arm. alongside our breakdown, we describe the methodology to measure the time spent in each component so that readers with access to precise cpu timers and a pcie analyzer can measure breakdowns on systems of their interest. such a breakdown is crucial for software developers, system architects, and researchers to guide their optimization efforts. as researchers ourselves, we use the breakdown to simulate the impacts and discuss the likelihoods of a set of optimizations that target the bottlenecks in today ' s high - performance communication.
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arxiv:2002.02563
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in this paper we give new consequences that follow from our formula for increments of the hardy - littlewood integral. main of these consequences is an $ \ zeta $ - equivalent of the fermat - wiles theorem. it is expressed purely by means of the riemann ' s zeta - function on the critical line and by the jacob ' s ladder.
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arxiv:2306.07648
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a small - $ x $ helicity evolution has been derived in 2016 - 18 and received an important modification in 2022. this article discusses its general framework and summarizes the recent theoretical developments, including the asymptotic behaviors of helicity pdfs and $ g _ 1 $ structure function at small $ x $. the latest fits to various polarized scattering data are also discussed. the results from this research program will provide important theoretical inputs for the future polarized small - $ x $ measurements at the electron - ion collider ( eic ).
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arxiv:2303.17532
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let $ d _ { t } $ and $ b _ { \ omega } $ denote the operators which cut the time content outside $ t $ and the frequency content outside $ \ omega $, respectively. the prolate spheroidal functions are the eigenfunctions of the operator $ p _ { t, \ omega } = d _ { t } b _ { \ omega } d _ { t } $. with the aim of formulating in precise mathematical terms the notion of nyquist rate, landau and pollack have shown that, asymptotically, the number of such functions with eigenvalue close to one is $ \ approx \ frac { \ left \ vert t \ right \ vert \ left \ vert \ omega \ right \ vert } { 2 \ pi } $. we have recently revisited this problem with a new approach : instead of counting the number of eigenfunctions with eigenvalue close to one, we count the maximum number of orthogonal $ \ epsilon $ - pseudoeigenfunctions with $ \ epsilon $ - pseudoeigenvalue one. precisely, we count how many orthogonal functions have a maximum of energy $ \ epsilon $ outside the domain $ t \ times \ omega $, in the sense that $ \ left \ vert p _ { t, \ omega } f - f \ right \ vert ^ { 2 } \ leq \ epsilon $. we have recently discovered that the sharp asymptotic number is $ \ approx ( 1 - \ epsilon ) ^ { - 1 } \ frac { \ left \ vert t \ right \ vert \ left \ vert \ omega \ right \ vert } { 2 \ pi } $. the proof involves an explicit construction of the pseudoeigenfunctions of $ p _ { t, \ omega } $. when $ t $ and $ \ omega $ are intervals we call them pseudo prolate spheroidal functions. in this paper we explain how they are constructed.
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arxiv:1503.03497
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we describe a local - power law scaling theory for the mean dimensionless electric current $ nu $ in turbulent electroconvection. the experimental system consists of a weakly conducting, submicron thick liquid crystal film supported in the annulus between concentric circular electrodes. it is driven into electroconvection by an applied voltage between its inner and outer edges. at sufficiently large voltage differences, the flow is unsteady and electric charge is turbulently transported between the electrodes. our theoretical development, which closely parallels the grossmann - lohse model for turbulent thermal convection, predicts the local - power law $ nu \ sim f ( \ gamma ) { \ cal r } ^ { \ gamma } { \ cal p } ^ { \ delta } $. $ { \ cal r } $ and $ { \ cal p } $ are dimensionless numbers that are similar to the rayleigh and prandtl numbers of thermal convection, respectively. the dimensionless function $ f ( \ gamma ) $, which is specified by the model, describes the dependence of $ nu $ on the aspect ratio $ \ gamma $. we find that measurements of $ nu $ are consistent with the theoretical model.
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arxiv:physics/0501005
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- 8, based on desurvire optimized laser amplification technology. it went into operation in 1988. in the late 1990s through 2000, industry promoters, and research companies such as kmi, and rhk predicted massive increases in demand for communications bandwidth due to increased use of the internet, and commercialization of various bandwidth - intensive consumer services, such as video on demand, internet protocol data traffic was increasing exponentially, at a faster rate than integrated circuit complexity had increased under moore ' s law. = = concepts = = = = = basic elements of a telecommunication system = = = = = = = transmitter = = = = transmitter ( information source ) that takes information and converts it to a signal for transmission. in electronics and telecommunications a transmitter or radio transmitter is an electronic device which, with the aid of an antenna, produces radio waves. in addition to their use in broadcasting, transmitters are necessary component parts of many electronic devices that communicate by radio, such as cell phones, = = = = transmission medium = = = = transmission medium over which the signal is transmitted. for example, the transmission medium for sounds is usually air, but solids and liquids may also act as transmission media for sound. many transmission media are used as communications channel. one of the most common physical media used in networking is copper wire. copper wire is used to carry signals to long distances using relatively low amounts of power. another example of a physical medium is optical fiber, which has emerged as the most commonly used transmission medium for long - distance communications. optical fiber is a thin strand of glass that guides light along its length. the absence of a material medium in vacuum may also constitute a transmission medium for electromagnetic waves such as light and radio waves. = = = = receiver = = = = receiver ( information sink ) that receives and converts the signal back into required information. in radio communications, a radio receiver is an electronic device that receives radio waves and converts the information carried by them to a usable form. it is used with an antenna. the information produced by the receiver may be in the form of sound ( an audio signal ), images ( a video signal ) or digital data. = = = wired communication = = = wired communications make use of underground communications cables ( less often, overhead lines ), electronic signal amplifiers ( repeaters ) inserted into connecting cables at specified points, and terminal apparatus of various types, depending on the type of wired communications used. = = = wireless communication = = = wireless communication involves the transmission of information over a distance without
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https://en.wikipedia.org/wiki/Telecommunications_engineering
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new concepts of rough natural number systems are introduced in this research paper from both formal and less formal perspectives. these are used to improve most rough set - theoretical measures in general rough set theory ( \ textsf { rst } ) and to represent rough semantics. the foundations of the theory also rely upon the axiomatic approach to granularity for all types of general \ textsf { rst } recently developed by the present author. the latter theory is expanded upon in this paper. it is also shown that algebraic semantics of classical \ textsf { rst } can be obtained from the developed dialectical counting procedures. fuzzy set theory is also shown to be representable in purely granule - theoretic terms in the general perspective of solving the contamination problem that pervades this research paper. all this constitutes a radically different approach to the mathematics of vague phenomena and suggests new directions for a more realistic extension of the foundations of mathematics of vagueness from both foundational and application points of view. algebras corresponding to a concept of \ emph { rough naturals } are also studied and variants are characterised in the penultimate section.
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arxiv:1408.1121
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using lattice simulations, we analyze the influence of uniform rotation on the equation of state of gluodynamics. for a sufficiently slow rotation, the free energy of the system can be expanded into a series of powers of angular velocity. we calculate the moment of inertia given by the quadratic coefficient of this expansion using both analytic continuation and derivative methods, which demonstrate a good agreement between the results. we find that the moment of inertia unexpectedly takes a negative value below the ` ` supervortical temperature ' ' $ t _ s = 1. 50 ( 10 ) t _ c $, vanishes at $ t = t _ s $, and becomes a positive quantity at higher temperatures. we discuss how our results are related to the scale anomaly and the magnetic gluon condensate. we point out that the negativity of the moment of inertia is in qualitative agreement with our previous lattice calculations, indicating that the rigid rotation increases the critical temperatures in gluodynamics and qcd.
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arxiv:2311.03947
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ammonia inversion lines are often used as probes of the physical conditions in the dense ism. the excitation temperature between the first two para metastable ( rotational ) levels is an excellent probe of the gas kinetic temperature. however, the calibration of this ammonia thermometer depends on the accuracy of the collisional rates with h2. here we present new collisional rates for ortho - nh3 and para - nh3 colliding with para - h2 ( j = 0 ) and we investigate the effects of these new rates on the excitation of ammonia. scattering calculations employ a new, high accuracy, potential energy surface computed at the coupled - cluster ccsd ( t ) level with a basis set extrapolation procedure. rates are obtained for all transitions involving ammonia levels with j < = 3 and for kinetic temperatures in the range 5 - 100 k. we find that the calibration curve of the ammonia thermometer - - which relates the observed excitation temperature between the first two para metastable levels to the gas kinetic temperature - - does not change significantly when these new rates are used. thus, the calibration of ammonia thermometer appears to be robust. effects of the new rates on the excitation temperature of inversion and rotation - inversion transitions are also found to be small.
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arxiv:0906.4468
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we extend the subrepresentation formula $ $ | f ( x ) | \ le c _ n \, i _ 1 ( | \ nabla f | ) ( x ) $ $ in several ways. first, we consider more general $ a _ 1 $ - potential operators on the right - hand side and prove local and global pointwise inequalities for these operators. second, we show that we can improve the right - hand side using fractional derivatives. finally, we extend our results to rough singular integral operators, similar to the main result in [ hmp1 ].
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arxiv:2406.13772
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the infinite discrete stable boltzmann maps are generalisations of the well - known uniform infinite planar quadrangulation in the case where large degree faces are allowed. we show that the simple random walk on these random lattices is always subdiffusive with exponent less than 1 / 3. our method is based on stationarity and geometric estimates obtained via the peeling process which are of own interest.
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arxiv:1910.09623
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the formation of population iii stars is investigated using resistive magnetohydrodynamic simulations. starting from a magnetized primordial prestellar cloud, we calculate the cloud evolution several hundreds of years after first protostar formation, resolving the protostellar radius. when the natal minihalo field strength is weaker than b \ lesssim 10 ^ - 13 ( n / 1 cm ^ - 3 ) ^ - 2 / 3 g ( n is the hydrogen number density ), magnetic effects can be ignored. in this case, fragmentation occurs frequently and a stellar cluster forms, in which stellar mergers and mass exchange between protostars contribute to the mass growth of these protostars. during the early gas accretion phase, the most massive protostar remains near the cloud centre, whereas some of the less massive protostars are ejected. the magnetic field significantly affects population iii star formation when b _ amb \ gtrsim 10 ^ - 12 ( n / 1 cm ^ - 3 ) ^ - 2 / 3 g. in this case, because the angular momentum around the protostar is effectively transferred by both magnetic braking and protostellar jets, the gas falls directly onto the protostar without forming a disk, and only a single massive star forms. in addition, a massive binary stellar system appears when b _ amb \ sim 10 ^ - 12 ( n / 1cm ^ - 3 ) ^ - 2 / 3 g. therefore, the magnetic field determines the end result of the formation process ( cluster, binary or single star ) for population iii stars. moreover, no persistent circumstellar disk appears around the protostar regardless of the magnetic field strength, which may influence the further evolution of population iii stars.
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arxiv:1308.2754
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loss of pod dehiscence is a key step during soybean [ glycine max ( l. ) merr. ] domestication. genome - wide association analysis for soybean shattering identified loci harboring pdh1, nst1a and shat1 - 5. pairwise epistatic interactions were observed, and the dehiscent pdh1 overcomes the resistance conferred by nst1a or shat1 - 5 locus, indicating that pdh1 predominates pod dehiscence expression. further candidate gene association analysis identified a nonsense mutation in nst1a associated with pod dehiscence. allele composition and population differential analyses unraveled that pdh1 and nst1a, but not shat1 - 5, underwent domestication and modern breeding selections. geographic analysis showed that in northeast china ( nec ), indehiscence at both pdh1 and nst1a were required by cultivated soybean ; while indehiscent pdh1 alone is capable of coping shattering in huang - huai - hai ( hhh ) valleys where it originated ; and no specific indehiscence was required in southern china ( sc ). geo - climatic investigation revealed strong correlation between relative humidity and frequency of indehiscent pdh1 across china. this study demonstrates that the epistatic interaction between pdh1 and nst1a fulfills a pivotal role in determining the level of resistance against pod dehiscence. humidity shapes the distribution of indehiscent alleles. our results also suggest that hhh valleys, not nec, was at least one of the origin centers of cultivated soybean.
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arxiv:1808.00996
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applied science is the application of the scientific method and scientific knowledge to attain practical goals. it includes a broad range of disciplines, such as engineering and medicine. applied science is often contrasted with basic science, which is focused on advancing scientific theories and laws that explain and predict natural or other phenomena. there are applied natural sciences, as well as applied formal and social sciences. applied science examples include genetic epidemiology which applies statistics and probability theory, and applied psychology, including criminology. = = applied research = = applied research is the use of empirical methods to collect data for practical purposes. it accesses and uses accumulated theories, knowledge, methods, and techniques for a specific state, business, or client - driven purpose. in contrast to engineering, applied research does not include analyses or optimization of business, economics, and costs. applied research can be better understood in any area when contrasting it with basic or pure research. basic geographical research strives to create new theories and methods that aid in explaining the processes that shape the spatial structure of physical or human environments. instead, applied research utilizes existing geographical theories and methods to comprehend and address particular empirical issues. applied research usually has specific commercial objectives related to products, procedures, or services. the comparison of pure research and applied research provides a basic framework and direction for businesses to follow. applied research deals with solving practical problems and generally employs empirical methodologies. because applied research resides in the messy real world, strict research protocols may need to be relaxed. for example, it may be impossible to use a random sample. thus, transparency in the methodology is crucial. implications for the interpretation of results brought about by relaxing an otherwise strict canon of methodology should also be considered. moreover, this type of research method applies natural sciences to human conditions : action research : aids firms in identifying workable solutions to issues influencing them. evaluation research : researchers examine available data to assist clients in making wise judgments. industrial research : create new goods / services that will satisfy the demands of a target market. ( industrial development would be scaling up production of the new goods / services for mass consumption to satisfy the economic demand of the customers while maximizing the ratio of the good / service output rate to resource input rate, the ratio of good / service revenue to material & energy costs, and the good / service quality. industrial development would be considered engineering. industrial development would fall outside the scope of applied research. ) gauging research : a type of evaluation research that uses a logic of rating to assess a process or program. it is a type
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https://en.wikipedia.org/wiki/Applied_science
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the widespread adoption of android devices for sensitive operations like banking and communication has made them prime targets for cyber threats, particularly advanced persistent threats ( apt ) and sophisticated malware attacks. traditional malware detection methods rely on binary classification, failing to provide insights into adversarial tactics, techniques, and procedures ( ttps ). understanding malware behavior is crucial for enhancing cybersecurity defenses. to address this gap, we introduce droidttp, a framework mapping android malware behaviors to ttps based on the mitre att & ck framework. our curated dataset explicitly links mitre ttps to android applications. we developed an automated solution leveraging the problem transformation approach ( pta ) and large language models ( llms ) to map applications to both tactics and techniques. additionally, we employed retrieval - augmented generation ( rag ) with prompt engineering and llm fine - tuning for ttp predictions. our structured pipeline includes dataset creation, hyperparameter tuning, data augmentation, feature selection, model development, and shap - based model interpretability. among llms, llama achieved the highest performance in tactic classification with a jaccard similarity of 0. 9583 and hamming loss of 0. 0182, and in technique classification with a jaccard similarity of 0. 9348 and hamming loss of 0. 0127. however, the label powerset xgboost model outperformed llms, achieving a jaccard similarity of 0. 9893 for tactic classification and 0. 9753 for technique classification, with a hamming loss of 0. 0054 and 0. 0050, respectively. while xgboost showed superior performance, the narrow margin highlights the potential of llm - based approaches in ttp classification.
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arxiv:2503.15866
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we present and review an algorithmic and theoretical framework for improving neural network architecture design via momentum. as case studies, we consider how momentum can improve the architecture design for recurrent neural networks ( rnns ), neural ordinary differential equations ( odes ), and transformers. we show that integrating momentum into neural network architectures has several remarkable theoretical and empirical benefits, including 1 ) integrating momentum into rnns and neural odes can overcome the vanishing gradient issues in training rnns and neural odes, resulting in effective learning long - term dependencies. 2 ) momentum in neural odes can reduce the stiffness of the ode dynamics, which significantly enhances the computational efficiency in training and testing. 3 ) momentum can improve the efficiency and accuracy of transformers.
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arxiv:2110.07034
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because we know little about the galactic force - field away from the plane, the galactic mass distribution is very ill - determined. i show that a microlensing survey of galaxies closer than 50 mpc would enable us to map in three dimensions the galactic density of stellar mass, which should be strictly less than the total mass density. a lower limit can be placed on the stellar mass needed at r < r _ 0 to generate the measured optical depth towards sources in the bulge. if the galaxy is barred, this limit is lower by a factor of up to two than in the axisymmetric case. even our limited knowledge of the galactic force field suffices to rule out the presence of the amount of mass an axisymmetric galaxy needs to generate the measured optical depth. several lines of argument imply that the galaxy is strongly barred only at r < 4 kpc, and if this is the case, even barred galaxy models cannot generate the measured optical depth without violating some constraint on the galactic force - field. galactic mass models that are based on the assumption that light traces mass, for which there is significant support in the inner galaxy, yield microlensing optical depths that are smaller than the measured value by a factor of more than 2. 5.
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arxiv:astro-ph/0004362
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consider a scenario where we have access to train data with both covariates and outcomes while test data only contains covariates. in this scenario, our primary aim is to predict the missing outcomes of the test data. with this objective in mind, we train parametric regression models under a covariate shift, where covariate distributions are different between the train and test data. for this problem, existing studies have proposed covariate shift adaptation via importance weighting using the density ratio. this approach averages the train data losses, each weighted by an estimated ratio of the covariate densities between the train and test data, to approximate the test - data risk. although it allows us to obtain a test - data risk minimizer, its performance heavily relies on the accuracy of the density ratio estimation. moreover, even if the density ratio can be consistently estimated, the estimation errors of the density ratio also yield bias in the estimators of the regression model ' s parameters of interest. to mitigate these challenges, we introduce a doubly robust estimator for covariate shift adaptation via importance weighting, which incorporates an additional estimator for the regression function. leveraging double machine learning techniques, our estimator reduces the bias arising from the density ratio estimation errors. we demonstrate the asymptotic distribution of the regression parameter estimator. notably, our estimator remains consistent if either the density ratio estimator or the regression function is consistent, showcasing its robustness against potential errors in density ratio estimation. finally, we confirm the soundness of our proposed method via simulation studies.
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arxiv:2310.16638
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we consider a discrete - time linear system for which the control input is updated at every sampling time, but the state is measured at a slower rate. we allow the state to be sampled according to a periodic schedule, which dictates when the state should be sampled along a period. given a desired average sampling interval, our goal is to determine sampling schedules that are optimal in the sense that they minimize the $ h _ 2 $ or the $ h _ \ infty $ closed - loop norm, under an optimal state - feedback control law. our results show that, when the desired average sampling interval is an integer, the optimal state sampling turns out to be evenly spaced. this result indicates that, for the $ h _ 2 $ and $ h _ \ infty $ performance metrics, there is relatively little benefit to go beyond constant - period sampling.
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arxiv:2310.17031
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the hypersurface in a 3 - dimensional vector space with an isolated quasi - homogeneous elliptic singularity of type e _ r, r = 6, 7, 8, has a natural poisson structure. we show that the family of del pezzo surfaces of the corresponding type e _ r provides a semiuniversal poisson deformation of that poisson structure. we also construct a deformation - quantization of the coordinate ring of such a del pezzo surface. to this end, we first deform the polynomial algebra c [ x, y, z ] to a noncommutative algebra with generators x, y, z and the following 3 relations ( where [ u, v ] _ t = uv - t. vu ) : [ x, y ] _ t = f _ 1 ( z ), [ y, z ] _ t = f _ 2 ( x ), [ z, x ] _ t = f _ 3 ( y ). this gives a family of calabi - yau algebras a ( f ) parametrized by a complex number t and a triple f = ( f _ 1, f _ 2, f _ 3 ), of polynomials in one variable of specifically chosen degrees. our quantization of the coordinate ring of a del pezzo surface is provided by noncommutative algebras of the form a ( f ) / ( g ) where ( g ) stands for the ideal of a ( f ) generated by a central element g, which generates the center of the algebra a ( f ) if f is generic enough.
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arxiv:0709.3593
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this paper introduces the condorj2 cluster management system. traditionally, cluster management systems such as condor employ a process - oriented approach with little or no use of modern database system technology. in contrast, condorj2 employs a data - centric, 3 - tier web - application architecture for all system functions ( e. g., job submission, monitoring and scheduling ; node configuration, monitoring and management, etc. ) except for job execution. employing a data - oriented approach allows the core challenge ( i. e., managing and coordinating a large set of distributed computing resources ) to be transformed from a relatively low - level systems problem into a more abstract, higher - level data management problem. preliminary results suggest that condorj2 ' s use of standard 3 - tier software represents a significant step forward to the design and implementation of large clusters ( 1, 000 to 10, 000 nodes ).
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arxiv:cs/0612137
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it security outsourcing is the process of contracting a third - party security service provider to perform, the full or partial it security functions of an organization. little is known about the factors influencing organizational decisions in outsourcing such a critical function. our review of the research and practice literature identified several managerial factors and legal factors. we found research in it security outsourcing to be immature and the focus areas not addressing the critical issues facing industry practice. we therefore present a research agenda consisting of fifteen questions to address five key gaps relating to knowledge of it security outsourcing, specifically effectiveness of the outcome, lived experience of the practice, the temporal dimension, multi - stakeholder perspectives, and the impact on it security practices, particularly agility in incident response.
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arxiv:2208.12875
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we present bolometric luminosities, black hole masses and eddington ratios for 42 luminous quasars at z > 6 using high signal - to - noise ratio vlt / x - shooter spectra, acquired in the enlarged eso large programme xqr - 30. in particular, we derive bolometric luminosities from the rest - frame 3000 a, luminosities using a bolometric correction from the literature, and the black hole masses by modelling the spectral regions around the civ 1549a and the mgii 2798a emission lines, with scaling relations calibrated in the local universe. we find that the black hole masses derived from both emission lines are in the same range, and the scatter of the measurements agrees with expectations from the scaling relations. the mgii - derived masses are between ~ ( 0. 8 - 12 ) x 10 ^ 9 msun, and the derived eddington ratios are within ~ 0. 13 - 1. 73, with a mean ( median ) of 0. 84 ( 0. 72 ). by comparing the total sample of quasars at z > 5. 8, from this work and from the literature, to a bolometric luminosity distribution - matched sample at z ~ 1. 5, we find that quasars at high redshift host slightly less massive black holes which accrete slightly more rapidly than at lower - z, with a difference in the mean eddington ratios of the two samples of ~ 0. 27, in agreement with recent literature work.
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arxiv:2306.16474
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we present high resolution spectroscopy in the [ \ ion { o } { 3 } ] $ \ lambda $ 5007 and h $ \ alpha $ lines of bright planetary nebulae in the milky way bulge and the dwarf galaxies m32, fornax, sagittarius, and ngc 6822 obtained at the observatorio astronomico nacional in the sierra san pedro martir using the manchester echelle spectrograph. we use the high signal - to - noise ( s / n ) observations of milky way bulge planetary nebulae to explore what kinematic information can be determined reliably when observing extragalactic planetary nebulae in the [ \ ion { o } { 3 } ] $ \ lambda $ 5007 line at modest s / n. we find that the intrinsic line widths measured in [ \ ion { o } { 3 } ] $ \ lambda $ 5007 and h $ \ alpha $ are very similar. over the range of s / n available in this sample, the line width we measure is independent of the s / n. finally, deviations from a gaussian line shape are small. thus, the line width of the [ \ ion { o } { 3 } ] $ \ lambda $ 5007 line in bright extragalactic planetary nebulae should reflect the kinematics of most of the mass in the ionized nebular shell.
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arxiv:0908.2111
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electrical engineering, and particularly, quantum field theory. complex analysis is particularly concerned with the analytic functions of complex variables ( or, more generally, meromorphic functions ). because the separate real and imaginary parts of any analytic function must satisfy laplace ' s equation, complex analysis is widely applicable to two - dimensional problems in physics. = = = functional analysis = = = functional analysis is a branch of mathematical analysis, the core of which is formed by the study of vector spaces endowed with some kind of limit - related structure ( e. g. inner product, norm, topology, etc. ) and the linear operators acting upon these spaces and respecting these structures in a suitable sense. the historical roots of functional analysis lie in the study of spaces of functions and the formulation of properties of transformations of functions such as the fourier transform as transformations defining continuous, unitary etc. operators between function spaces. this point of view turned out to be particularly useful for the study of differential and integral equations. = = = harmonic analysis = = = harmonic analysis is a branch of mathematical analysis concerned with the representation of functions and signals as the superposition of basic waves. this includes the study of the notions of fourier series and fourier transforms ( fourier analysis ), and of their generalizations. harmonic analysis has applications in areas as diverse as music theory, number theory, representation theory, signal processing, quantum mechanics, tidal analysis, and neuroscience. = = = differential equations = = = a differential equation is a mathematical equation for an unknown function of one or several variables that relates the values of the function itself and its derivatives of various orders. differential equations play a prominent role in engineering, physics, economics, biology, and other disciplines. differential equations arise in many areas of science and technology, specifically whenever a deterministic relation involving some continuously varying quantities ( modeled by functions ) and their rates of change in space or time ( expressed as derivatives ) is known or postulated. this is illustrated in classical mechanics, where the motion of a body is described by its position and velocity as the time value varies. newton ' s laws allow one ( given the position, velocity, acceleration and various forces acting on the body ) to express these variables dynamically as a differential equation for the unknown position of the body as a function of time. in some cases, this differential equation ( called an equation of motion ) may be solved explicitly. = = = measure theory = = = a measure on a set is a systematic way to assign a number to each suitable subset of that set, intuitively interpreted as its size
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https://en.wikipedia.org/wiki/Mathematical_analysis
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the evaluation of factual accuracy in large vision language models ( lvlms ) has lagged behind their rapid development, making it challenging to fully reflect these models ' knowledge capacity and reliability. in this paper, we introduce the first factuality - based visual question - answering benchmark in chinese, named chinesesimplevqa, aimed at assessing the visual factuality of lvlms across 8 major topics and 56 subtopics. the key features of this benchmark include a focus on the chinese language, diverse knowledge types, a multi - hop question construction, high - quality data, static consistency, and easy - to - evaluate through short answers. moreover, we contribute a rigorous data construction pipeline and decouple the visual factuality into two parts : seeing the world ( i. e., object recognition ) and discovering knowledge. this decoupling allows us to analyze the capability boundaries and execution mechanisms of lvlms. subsequently, we evaluate 34 advanced open - source and closed - source models, revealing critical performance gaps within this field.
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arxiv:2502.11718
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we briefly review various methods of implementing the bose - einstein effect into monte carlo generators. the weight methods are discussed in more detail ; in particular, our method employing a clustering algorithm is applies for the process e ^ + e ^ - - > w ^ + w ^ -. new results for the multiplicity distributions are presented.
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arxiv:hep-ph/9810492
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structured evolutionary algorithms have been investigated for some time. however, they have been under - explored specially in the field of multi - objective optimization. despite their good results, the use of complex dynamics and structures make their understanding and adoption rate low. here, we propose the general subpopulation framework that has the capability of integrating optimization algorithms without restrictions as well as aid the design of structured algorithms. the proposed framework is capable of generalizing most of the structured evolutionary algorithms, such as cellular algorithms, island models, spatial predator - prey and restricted mating based algorithms under its formalization. moreover, we propose two algorithms based on the general subpopulation framework, demonstrating that with the simple addition of a number of single - objective differential evolution algorithms for each objective the results improve greatly, even when the combined algorithms behave poorly when evaluated alone at the tests. most importantly, the comparison between the subpopulation algorithms and their related panmictic algorithms suggests that the competition between different strategies inside one population can have deleterious consequences for an algorithm and reveal a strong benefit of using the subpopulation framework. the code for san, the proposed multi - objective algorithm which has the current best results in the hardest benchmark, is available at the following https : / / github. com / zweifel / zweifel
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arxiv:1901.00266
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we propose an approach to modelling large - scale multi - agent dynamical systems allowing interactions among more than just pairs of agents using the theory of mean field games and the notion of hypergraphons, which are obtained as limits of large hypergraphs. to the best of our knowledge, ours is the first work on mean field games on hypergraphs. together with an extension to a multi - layer setup, we obtain limiting descriptions for large systems of non - linear, weakly - interacting dynamical agents. on the theoretical side, we prove the well - foundedness of the resulting hypergraphon mean field game, showing both existence and approximate nash properties. on the applied side, we extend numerical and learning algorithms to compute the hypergraphon mean field equilibria. to verify our approach empirically, we consider a social rumor spreading model, where we give agents intrinsic motivation to spread rumors to unaware agents, and an epidemics control problem.
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arxiv:2203.16223
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one phenomenological explanation of superluminal propagation of neutrinos, which may have been observed by opera and minos, is that neutrinos travel faster inside of matter than in vacuum. if so neutrinos exhibit refraction inside matter and should exhibit other manifestations of refraction, such as deflection and reflection. such refraction would be easily detectable through the momentum imparted to appropriately shaped refractive material inserted into the neutrino beam. for numi this could be as large as ~ 10g cm / s. if these effect were found, they would provide new ways of manipulating and detecting neutrinos. reasons why this scenario seems implausible are given, however it is still worthwhile to conduct simple searches for differential refraction of neutrinos.
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arxiv:1110.2170
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we describe a method for exactly diagonalizing clean $ d $ - dimensional lattice systems of independent fermions subject to arbitrary boundary conditions in one direction, as well as systems composed of two bulks meeting at a planar interface. our method builds on the generalized bloch theorem [ a. alase et al., phys. rev. b 96, 195133 ( 2017 ) ] and the fact that the bulk - boundary separation of the schrodinger equation is compatible with a partial fourier transform operation. bulk equations may display unusual features because they are relative eigenvalue problems for non - hermitian, bulk - projected hamiltonians. nonetheless, they admit a rich symmetry analysis that can simplify considerably the structure of energy eigenstates, often allowing a solution in fully analytical form. we illustrate our extension of the generalized bloch theorem to multicomponent systems by determining the exact andreev bound states for a simple sns junction. we then analyze the creutz ladder model, by way of a conceptual bridge from one to higher dimensions. upon introducing a new gaussian duality transformation that maps the creutz ladder to a system of two majorana chains, we show how the model provides a first example of a short - range chiral topological insulator hosting topological zero modes with a power - law profile. additional applications include the complete analytical diagonalization of graphene ribbons with both zigzag - bearded and armchair boundary conditions, and the analytical determination of the edge modes in a chiral $ p + ip $ two - dimensional topological superconductor. lastly, we revisit the phenomenon of majorana flat bands and anomalous bulk - boundary correspondence in a two - band gapless $ s $ - wave topological superconductor. we analyze the equilibrium josephson response of the system, showing how the presence of majorana flat bands implies a substantial enhancement in the $ 4 \ pi $ - periodic supercurrent.
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arxiv:1808.07555
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##s. 5. in number theory, may denote the prime omega function. that is, Ο ( n ) { \ displaystyle \ omega ( n ) } is the number of distinct prime factors of the integer n. = = brackets = = many types of bracket are used in mathematics. their meanings depend not only on their shapes, but also on the nature and the arrangement of what is delimited by them, and sometimes what appears between or before them. for this reason, in the entry titles, the symbol is used as a placeholder for schematizing the syntax that underlies the meaning. = = = parentheses = = = ( ) used in an expression for specifying that the sub - expression between the parentheses has to be considered as a single entity ; typically used for specifying the order of operations. ( ) (, ) (,..., ) 1. functional notation : if the first { \ displaystyle \ box } is the name ( symbol ) of a function, denotes the value of the function applied to the expression between the parentheses ; for example, f ( x ) { \ displaystyle f ( x ) }, sin ( x + y ) { \ displaystyle \ sin ( x + y ) }. in the case of a multivariate function, the parentheses contain several expressions separated by commas, such as f ( x, y ) { \ displaystyle f ( x, y ) }. 2. may also denote a product, such as in a ( b + c ) { \ displaystyle a ( b + c ) }. when the confusion is possible, the context must distinguish which symbols denote functions, and which ones denote variables. (, ) 1. denotes an ordered pair of mathematical objects, for example, ( Ο, 0 ) { \ displaystyle ( \ pi, 0 ) }. 2. if a and b are real numbers, β β { \ displaystyle - \ infty }, or + β { \ displaystyle + \ infty }, and a < b, then ( a, b ) { \ displaystyle ( a, b ) } denotes the open interval delimited by a and b. see ], [ for an alternative notation. 3. if a and b are integers, ( a, b ) { \ displaystyle ( a, b ) } may denote the greatest common divisor of a and b. notation gcd ( a
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https://en.wikipedia.org/wiki/Glossary_of_mathematical_symbols
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we consider the incompressible and stationary stokes equations on an infinite two - dimensional wedge with non - scaling invariant navier - slip boundary conditions. we prove well - posedness and higher regularity of the stokes problem in a certain class of weighted sobolev spaces. the novelty of this work is the occurrence of two different scalings in the boundary condition, which is not treated so far for the stokes system in unbounded wedge - type domains. these difficulties are overcome by first constructing a variational solution in a second order weighted sobolev space and subsequently proving higher regularity up to the tip of the wedge by employing an iterative scheme. we believe that this method can be used for other problems with variational structure and multiple scales.
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arxiv:2407.15517
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it has been demonstrated that deep neural networks outperform traditional machine learning. however, deep networks lack generalisability, that is, they will not perform as good as in a new ( testing ) set drawn from a different distribution due to the domain shift. in order to tackle this known issue, several transfer learning approaches have been proposed, where the knowledge of a trained model is transferred into another to improve performance with different data. however, most of these approaches require additional training steps, or they suffer from catastrophic forgetting that occurs when a trained model has overwritten previously learnt knowledge. we address both problems with a novel transfer learning approach that uses network aggregation. we train dataset - specific networks together with an aggregation network in a unified framework. the loss function includes two main components : a task - specific loss ( such as cross - entropy ) and an aggregation loss. the proposed aggregation loss allows our model to learn how trained deep network parameters can be aggregated with an aggregation operator. we demonstrate that the proposed approach learns model aggregation at test time without any further training step, reducing the burden of transfer learning to a simple arithmetical operation. the proposed approach achieves comparable performance w. r. t. the baseline. besides, if the aggregation operator has an inverse, we will show that our model also inherently allows for selective forgetting, i. e., the aggregated model can forget one of the datasets it was trained on, retaining information on the others.
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arxiv:2206.13399
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we submit the viewpoint that, perhaps, some of the controversies in gravitation occurred during this century are not due to insufficiencies of einstein ' s field equations, but rather to insufficiencies in the mathematics used for their treatment. for this purpose we treat the same equations with the novel, broader isomathematics and related isominkowskian geometry, and show an apparently final resolution in favor of existing relativities of controversies such as : the lack of invariance of the basic units of space and time ; lack of compatibility between gravitational and relativistic conservation laws ; lack of meaningful relativistic limit of gravitation ; and others. however, an apparent necessary condition for the resolution of these controversies is the abandonment of the notion of curvature used in this century in favor of a conceptual and mathematical broader notion. a number of intriguing implications and experimental verifications are pointed out.
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arxiv:physics/9707018
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using combinatorial covering properties, we show that there is no concentrated set of reals of size $ \ omega _ 2 $ in the miller model. the main result refutes a conjecture of bartoszy \ ' { n } ski and halbeisen. we also prove that there are no $ \ gamma $ - set of reals of size $ \ omega _ 2 $ in the miller model.
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arxiv:2310.03864
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based on systematic first - principles density - functional theory ( dft ) simulations, we predict that the zigzag gan nanoribbons ( zgannr ) can be used both as highly efficient co detectors as well as spin filters. our calculations performed both on infinitely long nanoribbons, and also on finite strands, suggest that : ( a ) co binds strongly at the edges of zgannrs, and ( b ) that several of the resultant configurations exhibit half - metallic behavior. we considered various edge - passivation sites and found that all the resultant structures are thermodynamically stable. the metallic, half - metallic, and semiconducting configurations are observed as a function of co passivation coverage. we also compute the current - voltage ( i - v ) characteristics of various structures using the landauer formalism and find that the devices made up of half - metallic configurations act as highly - efficient spin filters. the effect of co concentration is also investigated which suggests a viable way to not just tune the electronic band gap of zgannrs, but also their half metallicity. our simulations thus suggest a new direction of research for possible device applications of iii - v heterostructures.
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arxiv:2209.03078
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we develop the theory of minimal realizations and factorizations of rational functions where the coefficient space is a ring of the type introduced in our previous work, the scaled quaternions, which includes as special cases the quaternions and the split quaternions. the methods involved are not a direct generalization of the complex or quaternionic settings, and in particular, the adjoint is not the classical adjoint and we use properties of real hilbert spaces. this adjoint allows to define the counterpart of unitarity for matrix - rational functions, and we develop the corresponding theories of realizations and unitary factorizations. we also begin a theory of matrices in the underlying rings.
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arxiv:2411.06625
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abundant interfacial phenomena in nature, such as water droplets on lotus leaves and water transport in plant vessels, originate from partial - wetting phenomena, which can be well described by young ' s equation. it remains an intriguing question whether similar behaviors exist in active matter. in this letter, we present a clear demonstration of the partial - wetting phenomenon in a ternary laning system, which is a typical active system. a phase diagram is constructed in which the relative drift velocities of different components govern the transitions among drying, partial wetting, and complete wetting states. the mechanical balance on the contact lines of the partial - wetting phase described by young ' s equation is verified. a theoretical picture is proposed to explain the analogy of partial wetting in the laning system to that in the equilibrium system.
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arxiv:2504.14818
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we present first - principles studies on the orbital states of the layered perovskites ca $ _ { 2 - x } $ sr $ _ x $ ruo $ _ 4 $. the crossover from antiferromagnetic ( af ) mott insulator for $ x < 0. 2 $ to nearly ferromagnetic ( fm ) metal at $ x = 0. 5 $ is characterized by the systematic change of the $ xy $ orbital occupation. for the af side ( $ x < 0. 2 $ ), we present firm evidence for the $ xy $ ferro - orbital ordering. it is found that the degeneracy of $ t _ { 2g } $ ( or $ e _ g $ ) states is lifted robustly due to the two - dimensional ( 2d ) crystal - structure, even without the jahn - teller distortion of ruo $ _ 6 $. this effect dominates, and the cooperative occupation of $ xy $ orbital is concluded. in contrast to recent proposals, the resulting electronic structure explains well both the observed x - ray absorption spectra and the double peak structure of optical conductivity. for the fm side ( $ x = 0. 5 $ ), however, the $ xy $ orbital with half filling opens a pseudo - gap in the fm state and contributes to the spin $ s $ = 1 / 2 moment ( rather than $ s $ = 1 for $ x $ = 0. 0 case ) dominantly, while $ yz, zx $ states are itinerant with very small spin polarization, explaining the recent neutron data consistently.
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arxiv:cond-mat/0402122
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recent years have seen the discovery of a chiral spin liquid state - a bosonic analogue of a fractional quantum hall state first put forward by kalmeyer and laughlin in 1987 - in several deformations of the heisenberg model on the kagome lattice. here, we apply state - of - the - art numerical techniques to one such model, where breaking of the time - reversal symmetry drives the system into the chiral phase. our methods allow us to obtain explicit matrix - product state representations of the low - lying excitations of the chiral spin liquid state, including the topologically non - trivial semionic excitation. we characterize these excitations and study their energetics as the model is tuned towards a topological phase transition.
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arxiv:1506.03351
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multivariate ( mtv ) porous materials exhibit unique structural complexities based on diverse spatial arrangements of multiple building block combinations. these materials possess potential synergistic functionalities that exceed the sum of their individual components. however, the exponentially increasing design complexity of these materials poses challenges for accurate ground - state configuration prediction and design. to address this, a hamiltonian model was developed for quantum computing that integrates compositional, structural, and balance constraints, enabling efficient optimization of the mtv configurations. the model employs a graph - based representation to encode linkers as qubits. to validate our model, a variational quantum circuit was constructed and executed using the sampling vqe algorithm. simulations on experimentally known mtv porous materials successfully reproduced their ground - state configurations, demonstrating the validity of our model. furthermore, vqe calculations were performed on real quantum hardware for validation purposes, signaling a first step toward a practical quantum algorithm for the rational design of porous materials.
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arxiv:2502.06339
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learning data representations under uncertainty is an important task that emerges in numerous machine learning applications. however, uncertainty quantification ( uq ) techniques are computationally intensive and become prohibitively expensive for high - dimensional data. in this paper, we present a novel surrogate model for representation learning and uncertainty quantification, which aims to deal with data of moderate to high dimensions. the proposed model combines a neural network approach for dimensionality reduction of the ( potentially high - dimensional ) data, with a surrogate model method for learning the data distribution. we first employ a variational autoencoder ( vae ) to learn a low - dimensional representation of the data distribution. we then propose to harness polynomial chaos expansion ( pce ) formulation to map this distribution to the output target. the coefficients of pce are learned from the distribution representation of the training data using a maximum mean discrepancy ( mmd ) approach. our model enables us to ( a ) learn a representation of the data, ( b ) estimate uncertainty in the high - dimensional data system, and ( c ) match high order moments of the output distribution ; without any prior statistical assumptions on the data. numerical experimental results are presented to illustrate the performance of the proposed method.
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arxiv:2202.05063
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( abridged ) we present global disc and local shearing box simulations of planets interacting with a mhd turbulent disc. we examine the torque exerted by the disc on the embedded planets as a function of planet mass, and thus make a first study of orbital migration of planets due to interaction with turbulent discs. global simulations were performed for a disc with h / r = 0. 07 and planet masses m _ p = 3, 10, 30 earth masses, and 3 jupiter masses. shearing box runs were performed for values of ( m _ p / m _ * ) / ( h / r ) ^ 3 = 0. 1, 0. 3, 1. 0 and 2. 0, m _ * being the central mass. these allow embedded and gap forming planets to be examined. in all cases the instantaneous torque exerted on a planet showed strong fluctuations. in the embedded cases it oscillated between negative and positive values, and migration occurs as a random walk, unlike the usual type i migration. running time averages for embedded planets over 20 - 25 orbital periods show that large fluctuations occur on longer time scales, preventing convergence of the average torque to well defined values, or even to a well defined sign. fluctuations become relatively smaller for larger masses, giving better convergence, due to the planet ' s perturbation of the disc becoming larger than the turbulence in its vicinity. eventually gap formation occurs, with a transition to type ii migration. the existence of significant fluctuations occurring in turbulent discs on long time scales is important for lower mass embedded protoplanets. if significant fluctuations occur on the longest disc evolutionary time scales, convergence of torque running averages for practical purposes will not occur, and the migration behaviour of low mass protoplanets considered as an ensemble would be very different from predictions of type i theory for laminar discs.
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arxiv:astro-ph/0308360
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we present the results of a new model calculation of the gamma - ray background produced by unresolved blazars, using the second egret catalogue and taking account of flaring. these results are compared to the preliminary gamma - ray background spectrum reported recently by the egret team. we find that blazars can account for the entire extragalactic gamma - ray background observed by egret. in addition, the egret spectrum shows some evidence of a signature for the blazar background, in the form of a concavity in the spectrum.
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arxiv:astro-ph/9601120
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we investigate the non - abelian josephson effect in spinor bose - einstein condensates with double optical traps. we propose, for the first time, a real physical system which contains non - abelian josephson effects. the collective modes of this weak coupling system have very different density and spin tunneling characters comparing to the abelian case. we calculate the frequencies of the pseudo goldstone modes in different phases between two traps respectively, which are a crucial feature of the non - abelian josephson effects. we also give an experimental protocol to observe this novel effect in future experiments.
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arxiv:0809.4307
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we calculate the form factor of the quark energy momentum tensor and thereby extract the quark orbital angular momentum of the nucleon. the calculation is done on a quenched $ 16 ^ 3 \ times 24 $ lattice at $ \ beta = 6. 0 $ and with wilson fermions at $ \ kappa $ = 0. 148, 0. 152, 0. 154 and 0. 155. we calculate the disconnected insertion stochastically which employs the $ z _ 2 $ noise with an unbiased subtraction. this proves to be an efficient method of reduce the error from the noise. we find that the total quark contribution to the proton spin is $ 0. 29 \ pm 0. 07 $. from this we deduce that the quark orbital angular momentum is $ 0. 17 \ pm 0. 08 $ and predict the gluon spin to be $ 0. 21 \ pm 0. 07 $, i. e. about 40 % of the proton spin is due to the glue.
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arxiv:hep-lat/9908052
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. = = = imo performance = = = in comparison to other participating countries at the international mathematical olympiad, china has highest team scores and has won the all - members - gold imo with a full team the most number of times. = = in education = = the first reference to a book being used in learning mathematics in china is dated to the second century ce ( hou hanshu : 24, 862 ; 35, 1207 ). ma xu, who is a youth c. 110, and zheng xuan ( 127 β 200 ) both studied the nine chapters on mathematical procedures. christopher cullen claims that mathematics, in a manner akin to medicine, was taught orally. the stylistics of the suan shu shu from zhangjiashan suggest that the text was assembled from various sources and then underwent codification. = = see also = = chinese astronomy history of mathematics indian mathematics islamic mathematics japanese mathematics list of chinese discoveries list of chinese mathematicians numbers in chinese culture = = references = = = = = citations = = = = = = works cited = = = = = external links = = early mathematics texts ( chinese ) - chinese text project overview of chinese mathematics chinese mathematics through the han dynasty primer of mathematics by zhu shijie
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https://en.wikipedia.org/wiki/Chinese_mathematics
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how much of the combinatorial structure of a pointed polyhedron is contained in its vertex - facet incidences? not too much, in general, as we demonstrate by examples. however, one can tell from the incidence data whether the polyhedron is bounded. in the case of a polyhedron that is simple and " simplicial, " i. e., a d - dimensional polyhedron that has d facets through each vertex and d vertices on each facet, we derive from the structure of the vertex - facet incidence matrix that the polyhedron is necessarily bounded. in particular, this yields a characterization of those polyhedra that have circulants as vertex - facet incidence matrices.
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arxiv:math/0006225
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the goal of the paper is to study asymptotic behavior of the number of lost messages. long messages are assumed to be divided into a random number of packets which are transmitted independently of one another. an error in transmission of a packet results in the loss of the entire message. messages arrive to the $ m / gi / 1 $ finite buffer model and can be lost in two cases as either at least one of its packets is corrupted or the buffer is overflowed. with the parameters of the system typical for models of information transmission in real networks, we obtain theorems on asymptotic behavior of the number of lost messages. we also study how the loss probability changes if redundant packets are added. our asymptotic analysis approach is based on tauberian theorems with remainder.
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arxiv:math/0505596
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cooling flows, cluster mergers and motions of galaxies through the cluster gas with supersonic and sonic velocities must lead to large scale motions of the intracluster medium ( icm ). a high - resolution numerical simulation of x - ray cluster formation by norman and bryan predicts cluster - wide turbulence with v _ turb ~ 300 - 600 ~ km / s and eddy scales l _ outer ~ 100 - 500 kpc, the larger numbers being characteristic of turbulence near the virial radius, while the smaller numbers pertain to the core. the simulation also predicts the existence of ordered bulk flows in the core with v ~ 400 km / s on scales of several hundred kpc. in this paper we consider the observability of such fluid motions via the distortions it induces in the cmb via the kinematic sz effect, as well as via doppler broadening and shifting of metal lines in the x - ray spectrum. we estimate | \ delta t / t | _ kinematic < few x 10 ^ { - 6 } - - at or below current limits of detectability. however, we find that an energy resolution of a few ev is sufficient to detect several doppler shifted components in the 6. 7 kev fe line in the core of the cluster.
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arxiv:astro-ph/0310041
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we study the 1d model of conduction electrons interacting with local vibronic modes. states in the conduction band are two - fold degenerate both in orbital index and spin. it is shown that such 1d system has a strong tendency to superconductivity. the superconducting pairing originates from coupling of two charge density waves ; the scaling dimension of the order parameter is close to 1 / 4.
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arxiv:cond-mat/9502023
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we investigate the evolution of the homogeneous and isotropic universe within the framework of the effective string gravity with string - loop modifications of dilaton couplings. in the case of barotropic perfect fluid as a nongravitational source the set of cosmological equations is presented in the form of the third - order autonomous dynamical system. the cases are considered when this system is integrable in terms of integrals depending on dilaton coupling functions. without specifying these functions we describe generic evolution of the universe, using dynamical systems methods. the critical points and their stability are found for all regions of the parameters. the qualitatively different phase space diagrams are presented for the spatially - flat, closed and open universes. the case of the tree - level models is considered separately. the issue of dilaton stabilization is discussed within the framework of damour - polyakov mechanism.
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arxiv:gr-qc/9812082
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due to label scarcity and covariate shift happening frequently in real - world studies, transfer learning has become an essential technique to train models generalizable to some target populations using existing labeled source data. most existing transfer learning research has been focused on model estimation, while there is a paucity of literature on transfer inference for model accuracy despite its importance. we propose a novel $ \ mathbf { d } $ oubly $ \ mathbf { r } $ obust $ \ mathbf { a } $ ugmented $ \ mathbf { m } $ odel $ \ mathbf { a } $ ccuracy $ \ mathbf { t } $ ransfer $ \ mathbf { i } $ nferen $ \ mathbf { c } $ e ( dramatic ) method for point and interval estimation of commonly used classification performance measures in an unlabeled target population using labeled source data. specifically, dramatic derives and evaluates the risk model for a binary response $ y $ against some low dimensional predictors $ \ mathbf { a } $ on the target population, leveraging $ y $ from source data only and high dimensional adjustment features $ \ mathbf { x } $ from both the source and target data. the proposed estimators are doubly robust in the sense that they are $ n ^ { 1 / 2 } $ consistent when at least one model is correctly specified and certain model sparsity assumptions hold. simulation results demonstrate that the point estimation have negligible bias and the confidence intervals derived by dramatic attain satisfactory empirical coverage levels. we further illustrate the utility of our method to transfer the genetic risk prediction model and its accuracy evaluation for type ii diabetes across two patient cohorts in mass general brigham ( mgb ) collected using different sampling mechanisms and at different time points.
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arxiv:2208.05134
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we propose a scheme for generating vibrational pair coherent states of the motion of an ion in a two - dimensional trap. in our scheme, the trapped ion is excited bichromatically by three laser beams along different directions in the x - y plane of the ion trap. we show that if the initial vibrational state is given by a two - mode fock state, the final steady state, indicated by the extinction of the fluorescence emitted by the ion, is a pure state. the motional state of the ion in the equilibrium realizes that of the highly - correlated pair coherent state.
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arxiv:quant-ph/9604010
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a theory of existence and uniqueness is developed for general stochastic differential mean field games with common noise. the concepts of strong and weak solutions are introduced in analogy with the theory of stochastic differential equations, and existence of weak solutions for mean field games is shown to hold under very general assumptions. examples and counter - examples are provided to enlighten the underpinnings of the existence theory. finally, an analog of the famous result of yamada and watanabe is derived, and it is used to prove existence and uniqueness of a strong solution under additional assumptions.
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arxiv:1407.6181
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we solve an open problem of herfort and ribes : profinite frobenius groups of certain type do occur as closed subgroups of free profinite products of two profinite groups. this also solves a question of pop about prosolvable subgroups of free profinite products.
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arxiv:1001.3599
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we prove that in a free group the length of the value of each variable in a minimal solution of a standard quadratic equation is bounded by $ 2s $ for orientable equation and by $ 12s ^ 4 $ for non - orientable equation, where $ s $ is the sum of the lengths of the coefficients
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arxiv:1107.2843
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the language of graph theory, or network science, has proven to be an exceptional tool for addressing myriad problems in neuroscience. yet, the use of networks is predicated on a critical simplifying assumption : that the quintessential unit of interest in a brain is a dyad - - two nodes ( neurons or brain regions ) connected by an edge. while rarely mentioned, this fundamental assumption inherently limits the types of neural structure and function that graphs can be used to model. here, we describe a generalization of graphs that overcomes these limitations, thereby offering a broad range of new possibilities in terms of modeling and measuring neural phenomena. specifically, we explore the use of \ emph { simplicial complexes }, a theoretical notion developed in the field of mathematics known as algebraic topology, which is now becoming applicable to real data due to a rapidly growing computational toolset. we review the underlying mathematical formalism as well as the budding literature applying simplicial complexes to neural data, from electrophysiological recordings in animal models to hemodynamic fluctuations in humans. based on the exceptional flexibility of the tools and recent ground - breaking insights into neural function, we posit that this framework has the potential to eclipse graph theory in unraveling the fundamental mysteries of cognition.
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arxiv:1601.01704
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quantum process tomography ( qpt ), used for reconstruction of an unknown quantum process from measurement data, is a fundamental tool for the diagnostic and full characterization of quantum systems. it relies on querying a set of quantum states as input to the quantum process. previous works commonly use a straightforward strategy to select a set of quantum states randomly, overlooking differences in informativeness among quantum states. since querying the quantum system requires multiple experiments that can be prohibitively costly, it is always the case that there are not enough quantum states for high - quality reconstruction. in this paper, we propose a general framework for active learning ( al ) to adaptively select a set of informative quantum states that improves the reconstruction most efficiently. in particular, we introduce a learning framework that leverages the widely - used variational quantum circuits ( vqcs ) to perform the qpt task and integrate our al algorithms into the query step. we design and evaluate three various types of al algorithms : committee - based, uncertainty - based, and diversity - based, each exhibiting distinct advantages in terms of performance and computational cost. additionally, we provide a guideline for selecting algorithms suitable for different scenarios. numerical results demonstrate that our algorithms achieve significantly improved reconstruction compared to the baseline method that selects a set of quantum states randomly. moreover, these results suggest that active learning based approaches are applicable to other complicated learning tasks in large - scale quantum information processing.
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arxiv:2412.20925
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the main goal of this research is to develop the concepts of a revolutionary processor system called functional processor system. the fairly novel work carried out in this proposal concentrates on decoding of function pipelines and distributing it in fpus as a part of scheduling approach. as the functional programs are super - level programs that entails requirements only at functional level, decoding of functions and distribution of functions in the heterogeneous functional processor units are a challenge. we explored the possibilities of segregation of the functions from the application program and distributing the functions on the relevant fpus by using address mapping techniques. here we pursue the perception of feeding the functions into the processor farm rather than the processor fetching the instructions or functions and executing it. this work is carried out at theoretical levels and it requires a long way to go in the realization of this work in hardware perhaps with a large industrial team with a pragmatic time frame.
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arxiv:1001.3781
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we propose composite decode - forward ( df ) schemes for the two - way relay channel in both the full - and half - duplex modes by combining coherent relaying, independent relaying and partial relaying strategies. for the full - duplex mode, the relay partially decodes each user ' s information in each block and forwards this partial information coherently with the source user to the destination user in the next block as in block markov coding. in addition, the relay independently broadcasts a binning index of both users ' decoded information parts in the next block as in independent network coding. each technique has a different impact on the relay power usage and the rate region. we further analyze in detail the independent partial df scheme and derive in closed - form link regimes when this scheme achieves a strictly larger rate region than just time - sharing between its constituent techniques, direct transmission and independent df relaying, and when it reduces to a simpler scheme. for the half - duplex mode, we propose a 6 - phase time - division scheme that incorporates all considered relaying techniques and uses joint decoding simultaneously over all receiving phases. numerical results show significant rate gains over existing df schemes, obtained by performing link adaptation of the composite scheme based on the identified link regimes.
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arxiv:1504.07495
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a key factor for lunar mission planning is the ability to assess the local availability of raw materials. however, many potentially relevant measurements are scattered across a variety of scientific publications. in this paper we consider the viability of obtaining lunar composition data by leveraging llms to rapidly process a corpus of scientific publications. while leveraging llms to obtain knowledge from scientific documents is not new, this particular application presents interesting challenges due to the heterogeneity of lunar samples and the nuances involved in their characterization. accuracy and uncertainty quantification are particularly crucial since many materials properties can be sensitive to small variations in composition. our findings indicate that off - the - shelf llms are generally effective at extracting data from tables commonly found in these documents. however, there remains opportunity to further refine the data we extract in this initial approach ; in particular, to capture fine - grained mineralogy information and to improve performance on more subtle / complex pieces of information.
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arxiv:2504.20125
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this paper describes speaker verification ( sv ) systems submitted by the speakin team to the task 1 and task 2 of the far - field speaker verification challenge 2022 ( ffsvc2022 ). sv tasks of the challenge focus on the problem of fully supervised far - field speaker verification ( task 1 ) and semi - supervised far - field speaker verification ( task 2 ). in task 1, we used the voxceleb and ffsvc2020 datasets as train datasets. and for task 2, we only used the voxceleb dataset as train set. the resnet - based and repvgg - based architectures were developed for this challenge. global statistic pooling structure and mqmha pooling structure were used to aggregate the frame - level features across time to obtain utterance - level representation. we adopted am - softmax and aam - softmax to classify the resulting embeddings. we innovatively propose a staged transfer learning method. in the pre - training stage we reserve the speaker weights, and there are no positive samples to train them in this stage. then we fine - tune these weights with both positive and negative samples in the second stage. compared with the traditional transfer learning strategy, this strategy can better improve the model performance. the sub - mean and as - norm backend methods were used to solve the problem of domain mismatch. in the fusion stage, three models were fused in task1 and two models were fused in task2. on the ffsvc2022 leaderboard, the eer of our submission is 3. 0049 % and the corresponding mindcf is 0. 2938 in task1. in task2, eer and mindcf are 6. 2060 % and 0. 5232 respectively. our approach leads to excellent performance and ranks 1st in both challenge tasks.
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arxiv:2209.11625
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we consider a mathematical model that describes the flow of a nematic liquid crystal ( nlc ) film placed on a flat substrate, across which a spatially - varying electric potential is applied. due to their polar nature, nlc molecules interact with the ( nonuniform ) electric field generated, leading to instability of a flat film. implementation of the long wave scaling leads to a partial differential equation that predicts the subsequent time evolution of the thin film. this equation is coupled to a boundary value problem that describes the interaction between the local molecular orientation of the nlc ( the director field ) and the electric potential. we investigate numerically the behavior of an initially flat film for a range of film heights and surface anchoring conditions.
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arxiv:2011.08886
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in this paper, a new synesthetic documentation method that contributes to media art conservation is presented. this new method is called e - installation in analogy to the idea of the e - book as the electronic version of a real book. an e - installation is a virtualized media artwork that reproduces all synesthesia, interaction, and meaning levels of the artwork. advanced 3d modeling and telepresence technologies with a very high level of immersion allow the virtual re - enactment of works of media art that are no longer performable or rarely exhibited. the virtual re - enactment of a media artwork can be designed with a scalable level of complexity depending on whether it addresses professionals such as curators, art restorers, and art theorists or the general public. an e - installation is independent from the artwork ' s physical location and can be accessed via head - mounted display or similar data goggles, computer browser, or even mobile devices. in combination with informational and preventive conservation measures, the e - installation offers an intermediate and long - term solution to archive, disseminate, and pass down the milestones of media art history as a synesthetic documentation when the original work can no longer be repaired or exhibited in its full function.
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arxiv:1408.1362
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light primordial black holes ( pbhs ) with masses smaller than $ 10 ^ 9 $ g ( $ 10 ^ { - 24 } m _ \ odot $ ) evaporate before the onset of big - bang nucleosynthesis, rendering their detection rather challenging. if efficiently produced, they may have dominated the universe energy density. we study how such an early matter - dominated era can be probed successfully using gravitational waves ( gw ) emitted by local and global cosmic strings. while previous studies showed that a matter era generates a single - step suppression of the gw spectrum, we instead find a " double - step " suppression for local - string gw whose spectral shape provides information on the duration of the matter era. the presence of the two steps in the gw spectrum originates from gw being produced through two events separated in time : loop formation and loop decay, taking place either before or after the matter era. the second step - called the " knee " - is a novel feature which is universal to any early matter - dominated era and is not only specific to pbhs. detecting gws from cosmic strings with lisa, et, or bbo would set constraints on pbhs with masses between $ 10 ^ 6 $ and $ 10 ^ 9 $ g for local strings with tension $ g \ mu = 10 ^ { - 11 } $, and pbhs masses between $ 10 ^ 4 $ and $ 10 ^ 9 $ g for global strings with symmetry - breaking scale $ \ eta = 10 ^ { 15 } ~ \ mathrm { gev } $. effects from the spin of pbhs are discussed.
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arxiv:2304.04793
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we analytically derive the effective layer elastic energy of smectic - a and smectic - c liquid crystals by adiabatic elimination of the orientational degree of freedom from the generalized chen - lubensky model. in the smectic - a phase, the effective layer bending elastic modulus is calculated as a function of the wavelength of the layer undulation mode. it turns out that an unlocking of the layer normal and the director reduces the layer bending rigidity for wavelengths smaller than the director penetration length. in the achiral smectic - c phase, an anisotropic bending elasticity appears due to the coupling between the layer displacement and director. the effective layer bending rigidity is calculated as a function of the angle $ \ vartheta $ between the layer undulation wave - vector and the director field. we compute the free energy minimizer $ \ vartheta = \ theta $. it turns out that $ \ theta $ varies from $ 0 \ deg $ to $ 90 \ deg $ depending on the tilt angle, undulation wave - length and other elastic constants. we also discover a new important characteristic length and the discontinuous change of $ \ theta $. using the elastic constants of chen - lubensky model, we determine the parameters of the more macroscopic model [ y. hatwalne and t. c. lubensky, phys. rev. e { \ bf 52 }, 6240 ( 1995 ) ]. we then discuss the hydrodynamics, and demonstrate the alignment of director and the propagation of the anisotropic layer displacement wave in the presence of an oscillatory wall and a vibrating cylindrical source respectively.
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arxiv:0711.1659
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we study dynamics of freely cooling granular gases in two - dimensions using large - scale molecular dynamics simulations. we find that for dilute systems the typical kinetic energy decays algebraically with time, e ( t ) ~ t ^ { - 1 }, in the long time limit. asymptotically, velocity statistics are characterized by a universal gaussian distribution, in contrast with the exponential high - energy tails characterizing the early homogeneous regime. we show that in the late clustering regime particles move coherently as typical local velocity fluctuations, delta v, are small compared with the typical velocity, delta v / v ~ t ^ { - 1 / 4 }. furthermore, locally averaged shear modes dominate over acoustic modes. the small thermal velocity fluctuations suggest that the system can be heuristically described by burgers - like equations.
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arxiv:cond-mat/0209412
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fatigue life of components or test specimens often exhibit a significant scatter. furthermore, size effects have a non - negligible influence on fatigue life of parts with different geometries. we present a new probabilistic model for low - cycle fatigue ( lcf ) in the context of polycrystalline metal. the model takes size effects and inhomogeneous strain fields into account by means of the poisson point process ( ppp ). this approach is based on the assumption of independently occurring lcf cracks and the coffin - manson - basquin ( cmb ) equation. within the probabilistic model, we give a new and more physical interpretation of the cmb parameters which are in the original approach no material parameters in a strict sense, as they depend on the specimen geometry. calibration and validation of the proposed model is performed using results of strain controlled lcf tests of specimens with different surface areas. the test specimens are made of the nickel base superalloy rene 80.
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arxiv:1308.5842
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the calcium ( ca $ ^ { 2 + } $ ) signalling system is important for many cellular processes within the human body. signals are transmitted within the cell by releasing ca $ ^ { 2 + } $ from the endoplasmic reticulum ( er ) into the cytosol via clusters of ca $ ^ { 2 + } $ channels. mathematical models of ca $ ^ { 2 + } $ release via inositol 1, 4, 5 - trisphosphate receptors ( ip $ _ { 3 } $ r ) help with understanding underlying ca $ ^ { 2 + } $ dynamics but data - driven modelling of stochastic ca $ ^ { 2 + } $ release events, known as ca $ ^ { 2 + } $ puffs, is a difficult challenge. parameterising markov models for representing the ip $ _ { 3 } $ r with steady - state single channel data obtained at fixed combinations of the ligands ca $ ^ { 2 + } $ and inositol - trisphosphate ( ip $ _ { 3 } $ ) has previously been demonstrated to be insufficient. however, by extending an ip $ _ { 3 } $ r model based on steady - state data with an integral term that incorporates the delayed response of the channel to varying ca $ ^ { 2 + } $ concentrations we succeed in generating realistic ca $ ^ { 2 + } $ puffs. by interpreting the integral term as a weighted average of ca $ ^ { 2 + } $ concentrations that extend over a time interval of length $ \ tau $ into the past we conclude that the ip $ _ { 3 } $ r requires a certain amount of memory of past ligand concentrations.
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arxiv:2401.17326
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we present a microscopic theory of the magnetic quadrupole moment density $ \ mathcal { q } _ { ij } $ in periodic crystals with combined time reversal ( $ \ mathcal { t } $ ) and inversion ( $ \ mathcal { i } $ ) symmetry. we obtain a gauge - invariant expression with clear physical interpretation and demonstrate the typical behaviour of $ \ mathcal { q } _ { ij } $ in a minimal two - band model that hosts a tilted dirac cone. we then show that $ \ mathcal { q } _ { ij } $ leads to an intrinsic nonlinear anomalous thermoelectric current. as an example, we calculate the nonlinear nernst and hall current in the loop - current model for cuprate superconductors, and demonstrate their unique behaviour and capability of indicating $ \ mathcal { ti } $ - invariance.
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arxiv:1803.06726
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in this study i proposed a filtering beliefs method for improving performance of partially observable markov decision processes ( pomdps ), which is a method wildly used in autonomous robot and many other domains concerning control policy. my method search and compare every similar belief pair. because a similar belief have insignificant influence on control policy, the belief is filtered out for reducing training time. the empirical results show that the proposed method outperforms the point - based approximate pomdps in terms of the quality of training results as well as the efficiency of the method.
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arxiv:2101.02178
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despite the success of deep learning ( dl ) serious reliability issues such as non - robustness persist. an interesting aspect is, whether these problems arise due to insufficient tools or due to fundamental limitations of dl. we study this question from the computability perspective, i. e., we characterize the limits imposed by the applied hardware. for this, we focus on the class of inverse problems, which, in particular, encompasses any task to reconstruct data from measurements. on digital hardware, a conceptual barrier on the capabilities of dl for solving finite - dimensional inverse problems has in fact already been derived. this paper investigates the general computation framework of blum - shub - smale ( bss ) machines which allows the processing and storage of arbitrary real values. although a corresponding real world computing device does not exist at the moment, research and development towards real number computing hardware, usually referred to by the term " neuromorphic computing ", has increased in recent years. in this work, we show that the framework of bss machines does enable the algorithmic solvability of finite dimensional inverse problems. our results emphasize the influence of the considered computing model in questions of accuracy and reliability.
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arxiv:2204.02066
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fashion compatibility learning is important to many fashion markets such as outfit composition and online fashion recommendation. unlike previous work, we argue that fashion compatibility is not only a visual appearance compatible problem but also a theme - matters problem. an outfit, which consists of a set of fashion items ( e. g., shirt, suit, shoes, etc. ), is considered to be compatible for a " dating " event, yet maybe not for a " business " occasion. in this paper, we aim at solving the fashion compatibility problem given specific themes. to this end, we built the first real - world theme - aware fashion dataset comprising 14k around outfits labeled with 32 themes. in this dataset, there are more than 40k fashion items labeled with 152 fine - grained categories. we also propose an attention model learning fashion compatibility given a specific theme. it starts with a category - specific subspace learning, which projects compatible outfit items in certain categories to be close in the subspace. thanks to strong connections between fashion themes and categories, we then build a theme - attention model over the category - specific embedding space. this model associates themes with the pairwise compatibility with attention, and thus compute the outfit - wise compatibility. to the best of our knowledge, this is the first attempt to estimate outfit compatibility conditional on a theme. we conduct extensive qualitative and quantitative experiments on our new dataset. our method outperforms the state - of - the - art approaches.
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arxiv:1912.06227
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in this article, we state the bohr - sommerfeld conditions around a singular value of hyperbolic type of the principal symbol of a self - adjoint semiclassical toeplitz operator on a compact connected k \ " { a } hler surface. these conditions allow the description of the spectrum of the operator in a fixed size neighbourhood of the singularity. we provide numerical computations for three examples, each associated to a different topology.
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arxiv:1309.5322
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the equation of state ( eos ) embodies thermodynamic properties of compressible fluid materials and usually has very complicated forms in real engineering applications, subject to the physical requirements of thermodynamics. the complexity of eos in form gives rise to the difficulty in analyzing relevant wave patterns. concerning the design of numerical algorithms, the complex eos causes the inefficiency of riemann solvers and even the loss of robustness, which hampers the development of godunov - type numerical schemes. in this paper, a strategy of local stiffened gas approximation is proposed for real materials. the stiffened gas eos is used to approximate general eos locally at each interface of computational control volumes so that the riemann solver can be significantly simplified. in the meantime, the generalized riemann problem ( grp ) solver is adopted not only for high resolution purpose but effective reflection of the local thermodynamics as well. the resulting scheme is demonstrated to be efficient and robust and numerical examples display the excellent performance of such an approximation.
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arxiv:2108.13780
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chromosomal aberrations are very frequent in leukemias and several recurring mutations capable of malignant transformation have been described. these mutations usually occur in hematopoietic stem cells ( hsc ), transforming them into leukemia stem cells. nup98 gene translocations are an example of such chromosomal aberrations ; these translocations produce a fusion protein containing the n - terminal portion of nup98 and the c - terminal of a fusion partner. over 75 % of nup98 fusions can interact with chromatin, and lead to changes in gene expression. therefore, i hypothesize that nup98 fusions act as rogue transcriptional regulators in the cell. collecting previously published gene expression data ( microarray ) from hscs expressing nup98 fusions, we can generate data to corroborate this hypothesis. several different fusions affect the expression of similar genes ; these are involved in a few biological processes in the cell : embryonic development, immune system formation and chromatin organization. deregulated genes also present similar transcription factor binding sites in their regulatory regions. these putative regulatory transcription factors are highly interconnected through protein - protein interactions and transcriptional regulation among themselves, and they have important roles in cell cycle regulation, embryonic development, hematopoiesis, apoptosis and chromatin modification.
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arxiv:1210.3949
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we consider a transversally conformal foliation $ \ mathcal { f } $ of a closed manifold $ m $ endowed with a smooth riemannian metric whose restriction to each leaf is negatively curved. we prove that it satisfies the following dichotomy. either there is a transverse holonomy - invariant measure for $ \ mathcal { f } $, or the foliated geodesic flow admits a finite number of physical measures, which have negative transverse lyapunov exponents and whose basin cover a set full for the lebesgue measure. we also give necessary and sufficient conditions for the foliated geodesic flow to be partially hyperbolic in the case where the foliation is transverse to a projective circle bundle over a closed hyperbolic surface.
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arxiv:1512.01842
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epitaxial niobium - nitride thin films with a critical temperature of tc = 16k and a thickness of 100nm were fabricated on mgo ( 100 ) substrates by pulsed laser deposition. low - temperature magnetic force microscopy ( mfm ) images of the supercurrent vortices were measured after field cooling in a magnetic field of 3mt at various temperatures. temperature dependence of the penetration depth has been evaluated by a two - dimensional fitting of the vortex profiles in the monopole - monopole model. its subsequent fit to a single s - wave gap function results in the superconducting gap amplitude delta ( 0 ) = 2. 9 mev = 2. 1 * kb * tc, in perfect agreement with previous reports. the pinning force has been independently estimated from local depinning of individual vortices by lateral forces exerted by the mfm tip and from transport measurements. a good quantitative agreement between the two techniques shows that for low fields, b < < hc2, mfm is a powerful and reliable technique to probe the local variations of the pinning landscape. we also demonstrate that the monopole model can be successfully applied even for thin films with a thickness comparable to the penetration depth.
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arxiv:1101.4128
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we formulate equations of time - dependent density functional theory ( tddft ) in the co - moving lagrangian reference frame. the main advantage of the lagrangian description of many - body dynamics is that in the co - moving frame the current density vanishes, while the density of particles becomes independent of time. therefore a co - moving observer will see the picture which is very similar to that seen in the equilibrium system from the laboratory frame. it is shown that the most natural set of basic variables in tddft includes the lagrangian coordinate, $ \ bm \ xi $, a symmetric deformation tensor $ g _ { \ mu \ nu } $, and a skew - symmetric vorticity tensor, $ f _ { \ mu \ nu } $. these three quantities, respectively, describe the translation, deformation, and the rotation of an infinitesimal fluid element. reformulation of tddft in terms of new basic variables resolves the problem of nonlocality and thus allows to regularly derive a local nonadiabatic approximation for exchange correlation ( xc ) potential. stationarity of the density in the co - moving frame makes the derivation to a large extent similar to the derivation of the standard static local density approximation. we present a few explicit examples of nonlinear nonadiabatic xc functionals in a form convenient for practical applications.
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arxiv:cond-mat/0410205
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many properties of brownian motion on spaces with varying dimension ( bmvd in abbreviation ) have been explored in [ 5 ]. in this paper, we study brownian motion with drift on spaces with varying dimension ( bmvd with drift in abbreviation ). such a process can be conveniently defined by a regular dirichlet form that is not necessarily symmetric. the drift term is in some type of $ l ^ { p } $ space with $ p $ depending on the region of the state space. we show bmvd with drift can be related to a bmvd without drift via girsanov transform. through the method of duhamel ' s principle, it is established in this paper that the transition density of bmvd with drift has the same type of sharp two - sided gaussian bounds as that for bmvd ( without drift ). as a corollary, we derive green function estimate for bmvd with drift.
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arxiv:1610.09751
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we describe a new version of the 5d, exact, polarised, bethe - heitler event generator of $ \ gamma $ - ray conversions to $ e ^ + e ^ - $, developed in the context of the harpo project, that is able to simulate successive events with different photon energies and on different atomic targets without any substantial cpu overhead. the strong correlation between kinematic variables in the divergence of the five - dimensional differential cross section are mitigated by performing each step of the conversion in the appropriate lorentz frame. we extend the verification range down to 1 kev above threshold and up to 1 eev. this work could pave the way to the precise simulation of the high - performance $ \ gamma $ - ray telescopes and polarimeters of the post - fermi - lat area.
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arxiv:1802.08253
|
y * z ) = ( x * y ) * z, \ quad \ forall x : x * 1 = x, \ quad \ forall x : 1 * x = x, } or, shortly, x β ( y β z ) = ( x β y ) β z, x β 1 = x, 1 β x = x. { \ displaystyle x * ( y * z ) = ( x * y ) * z, \ qquad x * 1 = x, \ qquad 1 * x = x. } so, these formulas are identities in every monoid. as for any equality, the formulas without quantifier are often called equations. in other words, an identity is an equation that is true for all values of the variables. = = see also = = accounting identity list of mathematical identities law ( mathematics ) = = references = = = = = notes = = = = = = citations = = = = = = sources = = = = = external links = = the encyclopedia of equation online encyclopedia of mathematical identities ( archived ) a collection of algebraic identities archived 2011 - 10 - 01 at the wayback machine
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https://en.wikipedia.org/wiki/Identity_(mathematics)
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there is a growing consensus that in the present universe most baryons reside in galaxy clusters and groups in the form of highly ionized gas at temperatures of 10 ^ 6 ~ 10 ^ 8 k. the h - like and he - like ions of the heavy elements can produce absorption features - the so - called ` ` x - ray forest ' ' - in the x - ray spectrum of a background quasar. we investigate the distribution of the x - ray absorption lines produced by this gas under three different cosmological models : the standard cdm with omega _ 0 = 1, a flat model with omega _ 0 = 0. 3 and an open model with with omega _ 0 = 0. 3. we give a semi - analytic calculation of the x - ray forest distribution based on the press - schechter formalism, following perna & loeb ( 1998 ). we choose three ions ( o viii, si xiv and fe xxv ) and calculate the distribution functions, the number of absorbers along the los to a distant quasar vs. redshift and column density in a given ion. we find that significant differences in the evolution of the distribution functions among the three cosmological models. using monte carlo simulations, we simulate the distribution of x - ray absorption lines for 10, 000 random los. we find there are at least several o viii lines with column density higher than 10 ^ 16 cm ^ - 2. finally we explore the possibility of detecting the x - ray forest with current and upcoming x - ray missions and we present an xmm rgs simulation of a representative quasar x - ray spectrum.
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arxiv:astro-ph/0009305
|
current large language models ( llms ) have proven useful for analyzing financial data, but most existing models, such as bloomberggpt and fingpt, lack customization for specific user needs. in this paper, we address this gap by developing fingpt search agents tailored for two types of users : individuals and institutions. for individuals, we leverage retrieval - augmented generation ( rag ) to integrate local documents and user - specified data sources. for institutions, we employ dynamic vector databases and fine - tune models on proprietary data. there are several key issues to address, including data privacy, the time - sensitive nature of financial information, and the need for fast responses. experiments show that fingpt agents outperform existing models in accuracy, relevance, and response time, making them practical for real - world applications.
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arxiv:2410.15284
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