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recently, studies on deep reservoir computing ( rc ) highlighted the role of layering in deep recurrent neural networks ( rnns ). in this paper, the use of linear recurrent units allows us to bring more evidence on the intrinsic hierarchical temporal representation in deep rnns through frequency analysis applied to the state signals. the potentiality of our approach is assessed on the class of multiple superimposed oscillator tasks. furthermore, our investigation provides useful insights to open a discussion on the main aspects that characterize the deep learning framework in the temporal domain. | arxiv:1705.05782 |
the maximum mass of a neutron star ( ns ) is poorly defined. theoretical attempts to define this mass have thus far been unsuccessful. observational results currently provide the only means of narrowing this mass range down. eclipsing x - ray binary ( xrb ) pulsar systems are the only interacting binaries in which the mass of the ns may be measured directly. only 10 such systems are known to exist, 6 of which have yielded ns masses in the range 1. 06 - 1. 86 m $ _ { \ odot } $. we present the first orbital solutions of two further eclipsing systems, oao 1657 - 415 and exo 1722 - 363, whose donor stars have only recently been identified. using observations obtained using the vlt / isaac nir spectrograph, our initial work was concerned with providing an accurate spectral classification of the two counterpart stars, leading to a consistent explanation of the mechanism for spin period evolution of oao 1657 - 415. calculating radial velocities allowed orbital solutions for both systems to be computed. these are the first accurate determinations of the ns and counterpart masses in xrb pulsar systems to be made employing nir spectroscopy. | arxiv:1010.6001 |
traditional voxel - level multiple testing procedures in neuroimaging, mostly $ p $ - value based, often ignore the spatial correlations among neighboring voxels and thus suffer from substantial loss of power. we extend the local - significance - index based procedure originally developed for the hidden markov chain models, which aims to minimize the false nondiscovery rate subject to a constraint on the false discovery rate, to three - dimensional neuroimaging data using a hidden markov random field model. a generalized expectation - maximization algorithm for maximizing the penalized likelihood is proposed for estimating the model parameters. extensive simulations show that the proposed approach is more powerful than conventional false discovery rate procedures. we apply the method to the comparison between mild cognitive impairment, a disease status with increased risk of developing alzheimer ' s or another dementia, and normal controls in the fdg - pet imaging study of the alzheimer ' s disease neuroimaging initiative. | arxiv:1404.1371 |
the scalability of spin qubit devices is conditioned by qubit - to - qubit variability. disorder in the host materials indeed affects the wave functions of the confined carriers, which leads to variations in their charge and spin properties. charge disorder in the amorphous oxides is particularly detrimental owing to its long - range influence. here we analyze the effects of charge traps at the semiconductor / oxide interface, which are generally believed to play a dominant role in variability. we consider multiple random distributions of these interface traps and numerically calculate their impact on the chemical potentials, detuning and tunnel coupling of two adjacent quantum dots in sige heterostructure. our results highlight the beneficial screening effect of the metal gates. the surface of the heterostructure shall, therefore, be covered as much as possible by the gates in order to limit variability. we propose an alternative layout with tip - shaped gates that maximizes the coverage of the semiconductor / oxide interface and outperforms the usual planar layout in some regimes. this highlights the importance of design in the management of device - to - device variability. | arxiv:2402.18991 |
large language models ( llms ) often generate responses that deviate from user input or training data, a phenomenon known as " hallucination. " these hallucinations undermine user trust and hinder the adoption of generative ai systems. addressing hallucinations is essential for the advancement of llms. this paper introduces a comprehensive hallucination benchmark, incorporating both new extrinsic and existing intrinsic evaluation tasks, built upon clear taxonomy of hallucination. a major challenge in benchmarking hallucinations is the lack of a unified framework due to inconsistent definitions and categorizations. we disentangle llm hallucination from " factuality, " proposing a clear taxonomy that distinguishes between extrinsic and intrinsic hallucinations, to promote consistency and facilitate research. extrinsic hallucinations, where the generated content is not consistent with the training data, are increasingly important as llms evolve. our benchmark includes dynamic test set generation to mitigate data leakage and ensure robustness against such leakage. we also analyze existing benchmarks, highlighting their limitations and saturation. the work aims to : ( 1 ) establish a clear taxonomy of hallucinations, ( 2 ) introduce new extrinsic hallucination tasks, with data that can be dynamically regenerated to prevent saturation by leakage, ( 3 ) provide a comprehensive analysis of existing benchmarks, distinguishing them from factuality evaluations. | arxiv:2504.17550 |
formation of topological quantum phase on conventional semiconductor surface is of both scientific and technological interest. here, we demonstrate epitaxial growth of 2d topological insulator, i. e. quantum spin hall ( qsh ) state, on si ( 111 ) surface with a large energy gap, based on first - principles calculations. we show that si ( 111 ) surface functionalized with 1 / 3 monolayer of halogen atoms [ si ( 111 ) - sqrt ( 3 ) x sqrt ( 3 ) - x ( x = cl, br, i ) ] exhibiting a trigonal superstructure, provides an ideal template for epitaxial growth of heavy metals, such as bi, which self - assemble into a hexagonal lattice with high kinetic and thermodynamic stability. most remarkably, the bi overlayer is " atomically " bonded to but " electronically " decoupled from the underlying si substrate, exhibiting isolated qsh state with an energy gap as large as 0. 8 ev. this surprising phenomenon is originated from an intriguing substrate orbital filtering effect, which critically select the orbital composition around the fermi level leading to different topological phases. particularly, the substrate - orbital - filtering effect converts the otherwise topologically trivial freestanding bi lattice into a nontrivial phase ; while the reverse is true for au lattice. the underlying physical mechanism is generally applicable, opening a new and exciting avenue for exploration of large - gap topological surface / interface states. | arxiv:1411.5314 |
in gauge theories, the physical, experimentally observable spectrum consists only of gauge - invariant states. in the standard model the fr \ " ohlich - morchio - strocchi mechanism shows that these states can be adequately mapped to the gauge - dependent elementary w, z, higgs, and fermions. in theories with a more general gauge group and higgs sector, appearing in various extensions of the standard model, this has not to be the case. in this work we determine analytically the physical spectrum of $ \ mathrm { su } ( n > 2 ) $ gauge theories with a higgs field in the fundamental representation. we show that discrepancies between the spectrum predicted by perturbation theory and the observable physical spectrum arise. we confirm these analytic findings with lattice simulations for $ n = 3 $. | arxiv:1710.01941 |
we study a class of two - dimensional $ { \ cal n } = ( 0, 4 ) $ quiver gauge theories that flow to superconformal field theories. we find dualities for the superconformal field theories similar to the 4d $ { \ cal n } = 2 $ theories of class $ { \ cal s } $, labelled by a riemann surface $ { \ cal c } $. the dual descriptions arise from various pair - of - pants decompositions, that involves an analog of the $ t _ n $ theory. especially, we find the superconformal index of such theories can be written in terms of a topological field theory on $ { \ cal c } $. we interpret this class of scfts as the ones coming from compactifying 6d $ { \ cal n } = ( 2, 0 ) $ theory on $ \ mathbb { cp } ^ 1 \ times { \ cal c } $ | arxiv:1505.07110 |
we present the first large sample investigation of the properties of jets in fanaroff and riley type i radio galaxies ( fr - i ) based on data from the chandra archive. we explore relations between the properties of the jets and the properties of host galaxies in which they reside. we find previously unknown correlations to exist, relating photon index, volume emissivity, jet volume and luminosity, and find that the previously long held assumption of a relationship between luminosities at radio and x - ray wavelengths is linear in nature when bona fide fr - i radio galaxies are considered. in addition, we attempt to constrain properties which may play a key role in determination of the diffuse emission process. we test a simple model in which large - scale magnetic field variations are primarily responsible for determining jet properties ; however, we find that this model is inconsistent with our best estimates of the relative magnetic field strength in our sample. models of particle acceleration should attempt to account for our results if they are to describe fr - i jets accurately. | arxiv:1203.4720 |
this paper proves that the alon - tarsi number of any planar graph is at most $ 5 $, which gives an alternate proof of the $ 5 $ - choosability as well as the $ 5 $ - paintability of planar graphs. | arxiv:1711.10817 |
a complex $ \ omega $ - lie algebra is a vector space $ l $ over the complex field, equipped with a skew symmetric bracket $ [ -, - ] $ and a bilinear form $ \ omega $ such that $ $ [ [ x, y ], z ] + [ [ y, z ], x ] + [ [ z, x ], y ] = \ omega ( x, y ) z + \ omega ( y, z ) x + \ omega ( z, x ) y $ $ for all $ x, y, z \ in l $. the notion of $ \ omega $ - lie algebras, as a generalization of lie algebras, was introduced in nurowski \ cite { nur2007 }. fundamental results about finite - dimensional $ \ omega $ - lie algebras were developed by zusmanovich \ cite { zus2010 }. in \ cite { nur2007 }, all three dimensional non - lie real $ \ omega $ - lie algebras were classified. the purpose of this note is to provide an approach to classify all three dimensional non - lie complex $ \ omega $ - lie algebras. our method also gives a new proof of the classification in nurowski \ cite { nur2007 }. | arxiv:1305.5089 |
this study delves into the intricate challenges encountered by multi - agent systems ( mass ) operating within environments that are subject to deception attacks and markovian randomly switching topologies, particularly in the context of event - triggered secure consensus control. to address these complexities, a novel observer - based distributed event - triggered control scheme is introduced. this approach uses local information to dynamically adjust its triggered conditions, thereby enhancing the utilization of network resources. additionally, the design of the observer based secure consensus controller is distributed, leveraging the local information of each individual agent. furthermore, our event - triggered mechanism theoretically precludes the occurrence of zeno behavior in the triggering time series. finally, simulation results underscore the superiority of our proposed method when compared to existing techniques, thereby validating its effectiveness and applicability in the event - triggered secure consensus control of mass. | arxiv:2410.18440 |
we study nonlinear interactions in a strongly driven optomechanical cavity, in regimes where the interactions give rise to resonant scattering between optomechanical polaritons and are thus strongly enhanced. we use a keldysh formulation and self - consistent perturbation theory, allowing us to include self energy diagrams at all orders in the interaction. our main focus is understanding how non - equilibrium effects are modified by the polariton interactions, in particular the generation of non - zero effective polariton temperatures from vacuum fluctuations ( both in the incident cavity drive and in the mechanical dissipation ). we discuss how these effects could be observed in the output spectrum of the cavity. our work also provides a technical toolkit that will be useful for studies of more complex optomechanical systems. | arxiv:1501.01671 |
if two laser beams cross in a medium under shallow angle, the laser - induced grating consists of only a few grooves. in this situation, the phase between the grooves of the grating and its envelope is a decisive parameter for nonlinear effects. here, models are established for reproducing the groove - envelope phase effects that have been observed in the interference pattern of self - diffraction. four - wave mixing leads to interferences that are dominant in the spatial region between the orders of diffraction and with tilted interference fringes in the diagram of transverse coordinate vs. pulse delay. the vertical interference fringes that are dominant directly on the diffraction orders, experimentally observed at high intensity close to the damage threshold, require a model beyond four - wave mixing. a model is suggested that is based on optical transmission changes with confinement to regions in the medium that are smaller than the groove spacing. | arxiv:1608.08089 |
we investigate, in some details, symplectic equivalence between several conformal classes of lorentz metrics on the hyperboloid of one sheet $ h ^ { 1, 1 } \ cong t \ times t - \ delta $ and affine coadjoint orbits of the group $ diff _ + ( \ delta ) $ of orientation preserving diffeomorphisms of $ \ delta \ cong t $ with its natural projective structure. this will allow for generalizations, namely, to the case of arbitrary projective structures on null infinity. | arxiv:math/9806135 |
generally, discretization of partial differential equations ( pdes ) creates a sequence of linear systems $ a _ k x _ k = b _ k, k = 0, 1, 2,..., n $ with well - known and structured sparsity patterns. preconditioners are often necessary to achieve fast convergence when solving these linear systems using iterative solvers. we can use preconditioner updates for closely related systems instead of computing a preconditioner for each system from scratch. one such preconditioner update is the sparse approximate map ( sam ), which is based on the sparse approximate inverse preconditioner using a least squares approximation. a sam then acts as a map from one matrix in the sequence to another nearby one for which we have an effective preconditioner. to efficiently compute an effective sam update ( i. e., one that facilitates fast convergence of the iterative solver ), we seek to compute an optimal sparsity pattern. in this paper, we examine several sparsity patterns for computing the sam update to characterize optimal or near - optimal sparsity patterns for linear systems arising from discretized pdes. | arxiv:2406.17656 |
we establish, for smooth enough initial data, the global well - posedness ( existence, uniqueness and continuous dependence on initial data ) of solutions, for an inviscid three - dimensional { \ it slow limiting ocean dynamics } model. this model was derived as a strong rotation limit of the rotating and stratified boussinesg equations with periodic boundary conditions. to establish our results we utilize the tools developed for investigating the two - dimensional incompressible euler equations and linear transport equations. using a weaker formulation of the model we also show the global existence and uniqueness of solutions, for less regular initial data. | arxiv:1311.6064 |
we give the first examples of derived equivalences between varieties defined over non - closed fields where one has a rational point and the other does not. we begin with torsors over jacobians of curves over q and f _ q ( t ), and conclude with a pair of hyperkaehler 4 - folds over q. the latter is independently interesting as a new example of a transcendental brauer - manin obstruction to the hasse principle. | arxiv:1906.02261 |
this paper presents a table with estimates of the absolute magnitude of the sun and the conversions from $ vegamag $ to the ab and st systems for several wide - band filters used in ground and space - based observatories. these estimates use the dustless spectral energy distribution ( sed ) of vega, calibrated absolutely using the sed of sirius, to set the $ vegamag $ zero - points and a composite spectrum of the sun that coadds space - based observations from the ultra - violet to the near infrared with models of the solar atmosphere. the uncertainty of the absolute magnitudes is estimated comparing the synthetic colors with photometric measurements of solar analogs and is found to be $ \ sim $ 0. 02 magnitudes. combined with the uncertainty of $ \ sim $ 2 % in the calibration of the vega sed, the errors of these absolute magnitudes are $ \ sim $ 3 - - 4 %. using these seds, for the three of the most utilized filters in extragalactic work the estimated absolute magnitudes of the sun are $ m _ b $ = 5. 44, $ m _ v $ = 4. 81 and $ m _ k $ = 3. 27 mag in the $ vegamag $ system and $ m _ b $ = 5. 31, $ m _ v $ = 4. 80 and $ m _ k $ = 5. 08 mag in ab. | arxiv:1804.07788 |
hydrogen is rarely observed as ligand in hypervalent species, however, we find that high - pressure hydrogenation may stabilise hypervalent hydrogen - rich materials. focussing on ternary silicon hydrides via lithium doping, we find anions composed of hypervalent silicon with h ligands formed under high pressure. our results reveal two new hypervalent anions : layered - sih $ _ { 5 } ^ { - } $ and tricapped trigonal prismatic sih $ _ { 6 } ^ { 2 - } $. these differ from octahedral sih $ _ { 6 } ^ { 2 - } $ described in earlier studies. in addition, there are further hydrogen - rich structures li $ _ { 3 } $ sih $ _ { 10 } $ and li $ _ { 2 } $ sih $ _ { 6 + \ delta } $ which may be stabilised at high pressure. our work provides pointers to future investigations on hydrogen - rich materials. | arxiv:2010.01469 |
a well - known characteristic of pandemics such as covid - 19 is the high level of transmission heterogeneity in the infection spread : not all infected individuals spread the disease at the same rate and some individuals ( superspreaders ) are responsible for most of the infections. to quantify this phenomenon requires the analysis of the effect of the variance and higher moments of the infection distribution. working in the framework of stochastic branching processes, we derive an approximate analytical formula for the probability of an outbreak in the high variance regime of the infection distribution, verify it numerically and analyze its regime of validity in various examples. we show that it is possible for an outbreak not to occur in the high variance regime even when the basic reproduction number $ r _ 0 $ is larger than one and discuss the implications of our results for covid - 19 and other pandemics. | arxiv:2008.07352 |
modern embedded systems are evolving toward complex, heterogeneous architectures to accommodate increasingly demanding applications. driven by swap - c constraints, this shift has led to consolidating multiple systems onto single hardware platforms. static partitioning hypervisors offer a promising solution to partition hardware resources and provide spatial isolation between critical workloads. however, shared resources like the last - level cache and system bus can introduce temporal interference between virtual machines ( vms ), negatively impacting performance and predictability. over the past decade, academia and industry have developed interference mitigation techniques, such as cache partitioning and memory bandwidth reservation. however, configuring these techniques is complex and time - consuming. cache partitioning requires balancing cache sections across vms, while memory bandwidth reservation needs tuning bandwidth budgets and periods. testing all configurations is impractical and often leads to suboptimal results. moreover, understanding how these techniques interact is limited, as their combined use can produce compounded or conflicting effects on performance. static analysis tools estimating worst - case execution times offer guidance for configuring mitigation techniques but often fail to capture the complexity of modern multi - core systems. they typically focus on limited shared resources while neglecting others, such as iommus and interrupt controllers. to address these challenges, we present sp - impact, an open - source framework for analyzing and guiding interference mitigation configurations. sp - impact supports ( i ) cache coloring and ( ii ) memory bandwidth reservation, while evaluating their interactions and cumulative impact. by providing insights on real hardware, sp - impact helps optimize configurations for mixed - criticality systems, ensuring performance and predictability. | arxiv:2501.16245 |
in this work, we study emergent communication through the lens of cooperative multi - agent behavior in nature. using insights from animal communication, we propose a spectrum from low - bandwidth ( e. g. pheromone trails ) to high - bandwidth ( e. g. compositional language ) communication that is based on the cognitive, perceptual, and behavioral capabilities of social agents. through a series of experiments with pursuit - evasion games, we identify multi - agent reinforcement learning algorithms as a computational model for the low - bandwidth end of the communication spectrum. | arxiv:2011.14890 |
we present a method to represent input texts by contextualizing them jointly with dynamically retrieved textual encyclopedic background knowledge from multiple documents. we apply our method to reading comprehension tasks by encoding questions and passages together with background sentences about the entities they mention. we show that integrating background knowledge from text is effective for tasks focusing on factual reasoning and allows direct reuse of powerful pretrained bert - style encoders. moreover, knowledge integration can be further improved with suitable pretraining via a self - supervised masked language model objective over words in background - augmented input text. on triviaqa, our approach obtains improvements of 1. 6 to 3. 1 f1 over comparable roberta models which do not integrate background knowledge dynamically. on mrqa, a large collection of diverse qa datasets, we see consistent gains in - domain along with large improvements out - of - domain on bioasq ( 2. 1 to 4. 2 f1 ), textbookqa ( 1. 6 to 2. 0 f1 ), and duorc ( 1. 1 to 2. 0 f1 ). | arxiv:2004.12006 |
a mutant is a program obtained by syntactically modifying a program ' s source code ; an equivalent mutant is a mutant, which is functionally equivalent to the original program. mutants are primarily used in \ emph { mutation testing }, and when deriving a test suite, obtaining an equivalent mutant is considered to be highly negative, although these equivalent mutants could be used for other purposes. we present an approach that considers equivalent mutants valuable, and utilizes them for source code optimization. source code optimization enhances a program ' s source code preserving its behavior. we showcase a procedure to achieve source code optimization based on equivalent mutants and discuss proper mutation operators. experimental evaluation with java and c programs demonstrates the applicability of the proposed approach. an algorithmic approach for source code optimization using equivalent mutants is proposed. it is showcased that whenever applicable, the approach can outperform traditional compiler optimizations. | arxiv:1803.09571 |
the authors have proved in [ j. algebra appl. 14 ( 2015 ), no. 6 ] that the size of a stratifying system over a finite - dimensional hereditary path algebra $ a $ is at most $ n $, where $ n $ is the number of isomorphism classes of simple $ a $ - modules. moreover, if $ a $ is of euclidean type a stratifying system over $ a $ has at most $ n - 2 $ regular modules. in this work, we construct a family of stratifying systems of size $ n $ with a maximal number of regular elements, over the hereditary path algebra with quiver $ \ widetilde { \ mathbb { a } } _ { p, q } $, canonically oriented. | arxiv:1511.05976 |
loyalty programs are important tools for sharing platforms seeking to grow supply. online sharing platforms use loyalty programs to heavily subsidize resource providers, encouraging participation and boosting supply. as the sharing economy has evolved and competition has increased, the design of loyalty programs has begun to play a crucial role in the pursuit of maximal revenue. in this paper, we first characterize the optimal loyalty program for a platform with homogeneous users. we then show that optimal revenue in a heterogeneous market can be achieved by a class of multi - threshold loyalty program ( mtlp ) which admits a simple implementation - friendly structure. we also study the performance of loyalty programs in a setting with two competing sharing platforms, showing that the degree of heterogeneity is a crucial factor for both loyalty programs and pricing strategies. our results show that sophisticated loyalty programs that reward suppliers via stepwise linear functions outperform simple sign - up bonuses, which give them a one time reward for participating. | arxiv:1805.03581 |
we theoretically investigate a weakly - interacting degenerate bose gas coupled to an empty markovian bath. we show that in the universal phononic limit the system evolves towards an asymptotic state where an emergent temperature is set by the quantum noise of the outcoupling process. for situations typically encountered in experiments, this mechanism leads to significant cooling. such dissipative cooling supplements conventional evaporative cooling and dominates in settings where thermalization is highly suppressed, such as in a one - dimensional quasicondensate. | arxiv:1411.4946 |
we present a generalised framework for resolving the electrochemistry - diffusion interface and modelling hydrogen transport near a crack tip. the adsorption and absorption kinetics are captured by means of neumann - type generalised boundary conditions. the diffusion model includes the role of trapping, with a constant or evolving trap density, and the influence of the hydrostatic stress. both conventional plasticity and strain gradient plasticity are used to model the mechanical behaviour of the solid. notable differences are found in the estimated crack tip hydrogen concentrations when comparing with the common procedure of prescribing a constant hydrogen concentration at the crack surfaces. | arxiv:2004.05611 |
we show how to train a fully convolutional neural network to perform inverse rendering from a single, uncontrolled image. the network takes an rgb image as input, regresses albedo and normal maps from which we compute lighting coefficients. our network is trained using large uncontrolled image collections without ground truth. by incorporating a differentiable renderer, our network can learn from self - supervision. since the problem is ill - posed we introduce additional supervision : 1. we learn a statistical natural illumination prior, 2. our key insight is to perform offline multiview stereo ( mvs ) on images containing rich illumination variation. from the mvs pose and depth maps, we can cross project between overlapping views such that siamese training can be used to ensure consistent estimation of photometric invariants. mvs depth also provides direct coarse supervision for normal map estimation. we believe this is the first attempt to use mvs supervision for learning inverse rendering. | arxiv:1811.12328 |
the causal representation of multi - loop scattering amplitudes, obtained from the application of the loop - tree duality formalism, comprehensively elucidates, at integrand level, the behaviour of only physical singularities. this representation is found to manifest compact expressions for multi - loop topologies that have the same number of \ textit { vertices }. interestingly, integrands considered in former studies, with up - to six vertices and $ l $ internal lines, display the same structure of up - to four - loop ones. the former is an insight that there should be a correspondence between vertices and the collection of internal lines, \ textit { edges }, that characterise a multi - loop topology. by virtue of this relation, in this paper, we embrace an approach to properly classify multi - loop topologies according to vertices and edges. differently from former studies, we consider the most general topologies, by connecting vertices and edges in all possible ways. likewise, we provide a procedure to generate causal representation of multi - loop topologies by considering the structure of causal propagators. explicit causal representations of loop topologies with up - to nine vertices are provided. | arxiv:2102.05048 |
we propose a multitask pretraining approach zeroprompt for zero - shot generalization, focusing on task scaling and zero - shot prompting. while previous models are trained on only a few dozen tasks, we scale to 1, 000 tasks for the first time using real - world data. this leads to a crucial discovery that task scaling can be an efficient alternative to model scaling ; i. e., the model size has little impact on performance with an extremely large number of tasks. our results show that task scaling can substantially improve training efficiency by 30 times in flops. moreover, we present a prompting method that incorporates a genetic algorithm to automatically search for the best prompt for unseen tasks, along with a few other improvements. empirically, zeroprompt substantially improves both the efficiency and the performance of zero - shot learning across a variety of academic and production datasets. | arxiv:2201.06910 |
the heterogeneous computing paradigm represents a real programming challenge due to the proliferation of devices with different hardware characteristics. recently intel introduced oneapi, a new programming environment that allows code developed in dpc + + to be run on different devices such as cpus, gpus, fpgas, among others. this paper presents our first experiences in porting two cuda applications to dpc + + using the oneapi dpct tool. from the experimental work, it was possible to verify that dpct does not achieve 100 % of the migration task ; however, it performs most of the work, reporting the programmer of possible pending adaptations. additionally, it was possible to verify the functional portability of the dpc + + code obtained, having successfully executed it on different cpu and gpu architectures. | arxiv:2105.13489 |
a graph is $ ( h _ 1, h _ 2 ) $ - free for a pair of graphs $ h _ 1, h _ 2 $ if it contains no induced subgraph isomorphic to $ h _ 1 $ or $ h _ 2 $. in 2001, kr \ ' al ', kratochv \ ' { \ i } l, tuza, and woeginger initiated a study into the complexity of colouring for $ ( h _ 1, h _ 2 ) $ - free graphs. since then, others have tried to complete their study, but many cases remain open. we focus on those $ ( h _ 1, h _ 2 ) $ - free graphs where $ h _ 2 $ is $ \ overline { h _ 1 } $, the complement of $ h _ 1 $. as these classes are closed under complementation, the computational complexities of colouring and clique cover coincide. by combining new and known results, we are able to classify the complexity of colouring and clique cover for $ ( h, \ overline { h } ) $ - free graphs for all cases except when $ h = sp _ 1 + p _ 3 $ for $ s \ geq 3 $ or $ h = sp _ 1 + p _ 4 $ for $ s \ geq 2 $. we also classify the complexity of colouring on graph classes characterized by forbidding a finite number of self - complementary induced subgraphs, and we initiate a study of $ k $ - colouring for $ ( p _ r, \ overline { p _ r } ) $ - free graphs. | arxiv:1607.06757 |
rehabilitation engineering is the systematic application of engineering sciences to design, develop, adapt, test, evaluate, apply, and distribute technological solutions to problems confronted by individuals with disabilities. these individuals may have experienced a spinal cord injury, brain trauma, or any other debilitating injury or disease ( such as multiple sclerosis, parkinson ' s, west nile, als, etc. ). functional areas addressed through rehabilitation engineering may include mobility, communications, hearing, vision, and cognition, and activities associated with employment, independent living, education, and integration into the community. rehabilitation engineering and assistive technology society of north america, the association and certifying organization of professionals within the field of rehabilitation engineering and assistive technology in north america, defines the role of a rehabilitation engineer as well as the role of a rehabilitation technician, assistive technologist, and rehabiltiation technologist ( not all the same ) in the 2017 approved white paper available online on their website. = = qualifications = = while some rehabilitation engineers have master ' s degrees in rehabilitation engineering, usually a subspecialty of biomedical engineering, most rehabilitation engineers have undergraduate or graduate degrees in biomedical engineering, mechanical engineering, or electrical engineering. a portuguese university provides an undergraduate degree and a master ' s degree in rehabilitation engineering and accessibility. in the uk, there are 3 recognised training routes into rehabilitation engineering : ahcs practitioner training programme ( ptp ) higher / degree apprenticeship in healthcare science practitioner ( clinical engineering ) at uwe bristol or healthcare science ( rehabilitation engineering ) at swansea university leading to rct or ahcs registration as a clinical technologist / healthcare science practitioner. the scientist training programme ( stp ) leading to hcpc registration as a clinical scientist through the national school of healthcare science with applications open during january each year. training centres around the uk are accredited to provide the ipem clinical technologist training scheme leading to rct registration as a clinical technologist. in the uk, there are 3 professional registration bodies for rehabilitation engineers : the register of clinical technologists ( rct ) and administered through the institute of physics and engineering in medicine ( ipem ). the healthcare science practitioner register through the academy for healthcare science ( ahcs ) the health & care professions council ( hcpc ) for ipem, ahcs and acs. = = professional, scientific and technical associations = = many of the rehabilitation engineering professionals join multidisciplinary scientific and technical associations with a common interest in the field of assistive technology and accessibility. examples are resna - rehabilitation engineering and assistive | https://en.wikipedia.org/wiki/Rehabilitation_engineering |
classical hamiltonian ratchets have been recently successfully realized using cold atoms in driven optical lattices. here we study the current rectification of the motion of a quantum particle in a periodic potential exposed to an external ac field. the dc current appears due to the desymmetrization of floquet eigenstates, which become transporting. quantum dynamics enhances the dependence of the current on the initial phase of the driving field. by changing the laser field parameters which control the degree of space - time asymmetry, floquet eigenstates are tuned through avoided crossings. these quantum resonances induce resonant changes of the resulting current. the width, strength and position of these quantum resonances are tunable using control parameters of the experimental realization with cold atoms. | arxiv:cond-mat/0607558 |
we construct a family of general type surfaces with $ q = 4 $, $ p _ g = 6 $ and $ k ^ 2 = 24 $. these surfaces enjoy some interesting properties : they are lagrangian in their albanese variety and their canonical map is $ 2 : 1 $ onto a degree $ 12 $ surface in $ \ mathbb p ^ 5 $ with $ 44 $ even nodes. | arxiv:2502.13087 |
we believe that the extreme solar modulation of 3 - 60 mev galactic electrons measured by voyager in the heliosheath and the interpretation of this new data in terms of the rigidity dependence of the diffusion coefficient at low rigidities presented in this paper represents a major step in understanding diffusion theory as it applies to energetic particles. this description uses electron spectra measured at 5 different epochs and distances within the heliosheath. the diffusion dependence needed to explain the remarkable solar modulation effects observed for both electrons and higher rigidity protons as one progresses from the heliopause inward by ~ 25 au to the termination shock really has two distinct rigidity regimes. above a rigidity ~ pc the diffusion coefficient has a dependence ~ beta p, the modulation is ~ p and its magnitude increases linearly with radius in au according to the integral of dr / k. this integral defines a potential, beta, called the modulation potential, thus explaining the proton variations. at rigidities < pc, the diffusion coefficient is ~ beta and independent of rigidity. the modulation is also independent of rigidity but its magnitude depends on the modulation potential, thus explaining the electron modulation. one needs both electron and proton observations, together, to recognize the physical description of the solar modulation process. for the first time we have been able, using proton data at high rigidities and electron data at low rigidities, to put together a picture of the high and low rigidity diffusion coefficients and how they affect energetic particles in an astrophysical scale environment. | arxiv:1810.07154 |
clifford quantum circuits are elementary invertible transformations of quantum systems that map pauli operators to pauli operators. we study periodic one - parameter families of clifford circuits, called loops of clifford circuits, acting on $ \ mathsf { d } $ - dimensional lattices of prime $ p $ - dimensional qudits. we propose to use the notion of algebraic homotopy to identify topologically equivalent loops. we calculate homotopy classes of such loops for any odd $ p $ and $ \ mathsf { d } = 0, 1, 2, 3 $, and $ 4 $. our main tool is the hermitian k - theory, particularly a generalization of the maslov index from symplectic geometry. we observe that the homotopy classes of loops of clifford circuits in $ ( \ mathsf { d } + 1 ) $ - dimensions coincide with the quotient of the group of clifford quantum cellular automata modulo shallow circuits and lattice translations in $ \ mathsf { d } $ - dimensions. | arxiv:2306.09903 |
it can be conjectured that the colored jones function of a knot can be computed in terms of counting paths on the graph of a planar projection of a knot. on the combinatorial level, the colored jones function can be replaced by its weight system. we give two curious formulas for the weight system of a colored jones function : one in terms of the permanent of a matrix associated to a chord diagram, and another in terms of counting paths of intersecting chords. | arxiv:math/0203012 |
completeness of the real numbers ( every bounded increasing sequence of real numbers has a limit ). theorem iii. 2. 2 the bolzano – weierstrass theorem. theorem iii. 2. 2 ascoli ' s theorem : every bounded equicontinuous sequence of real functions on the unit interval has a uniformly convergent subsequence. every countable field embeds isomorphically into its algebraic closure. theorem iii. 3. 2 every countable commutative ring has a maximal ideal. theorem iii. 5. 5 every countable vector space over the rationals ( or over any countable field ) has a basis. theorem iii. 4. 3 for any countable fields k ⊆ l { \ displaystyle k \ subseteq l }, there is a transcendence basis for l { \ displaystyle l } over k { \ displaystyle k }. theorem iii. 4. 6 konig ' s lemma ( for arbitrary finitely branching trees, as opposed to the weak version described above ). theorem iii. 7. 2 for any countable group g { \ displaystyle g } and any subgroups h, i { \ displaystyle h, i } of g { \ displaystyle g }, the subgroup generated by h ∪ i { \ displaystyle h \ cup i } exists. p. 40 any partial function can be extended to a total function. various theorems in combinatorics, such as certain forms of ramsey ' s theorem. theorem iii. 7. 2 = = = arithmetical transfinite recursion atr0 = = = the system atr0 adds to aca0 an axiom that states, informally, that any arithmetical functional ( meaning any arithmetical formula with a free number variable n and a free set variable x, seen as the operator taking x to the set of n satisfying the formula ) can be iterated transfinitely along any countable well ordering starting with any set. atr0 is equivalent over aca0 to the principle of σ11 separation. atr0 is impredicative, and has the proof - theoretic ordinal γ 0 { \ displaystyle \ gamma _ { 0 } }, the supremum of that of predicative systems. atr0 proves the consistency of aca0, and thus by godel ' s theorem it is strictly stronger. the following assertions are equivalent to atr0 over rca0 : any two countable well orderings | https://en.wikipedia.org/wiki/Reverse_mathematics |
the epic pn ccd camera on board of xmm - newton is designed to perform high throughput imaging and spectroscopy as well as high resolution timing observations in the energy range of 0. 1 - 15 kev. a temporal resolution of milliseconds or microseconds, depending on the instrument mode and detector, is outstanding for ccd based x - ray cameras. in order to calibrate the different observing modes of the epic pn ccd, xmm - newton observations of the pulsars psr b1509 - 58, psr b0540 - 69 and the crab were performed during the calibration and performance verification phase. to determine the accuracy of the on board clock against coordinated universal time ( utc ), psr b1509 - 58 was observed simultaneously with xmm - newton and rxte in addition. the paper summarizes the current status of the clock calibration. | arxiv:astro-ph/0203207 |
the idea of this project is to study the protein structure and sequence relationship using the hidden markov model and artificial neural network. in this context we have assumed two hidden markov models. in first model we have taken protein secondary structures as hidden and protein sequences as observed. in second model we have taken protein sequences as hidden and protein structures as observed. the efficiencies for both the hidden markov models have been calculated. the results show that the efficiencies of first model is greater that the second one. these efficiencies are cross validated using artificial neural network. this signifies the importance of protein secondary structures as the main hidden controlling factors due to which we observe a particular amino acid sequence. this also signifies that protein secondary structure is more conserved in comparison to amino acid sequence. | arxiv:1206.3509 |
in the present paper, two discrete forms of appell function $ f _ 1 $ are introduced and studied. we examine the first discrete form in detail and give the results directly for the second. we study their regions of convergence, differential properties, integral representations, recursion relations, finite and infinite sums. the results and identities obtained in the paper are believed to be new and may find applications in various branches of science. | arxiv:2401.05677 |
we outline our techniques to characterise photospheric granulation as an astrophysical noise source. a four component parameterisation of granulation is developed that can be used to reconstruct stellar line asymmetries and radial velocity shifts due to photospheric convective motions. the four components are made up of absorption line profiles calculated for granules, magnetic intergranular lanes, non - magnetic intergranular lanes, and magnetic bright points at disc centre. these components are constructed by averaging fe i $ 6302 \ mathrm { \ aa } $ magnetically sensitive absorption line profiles output from detailed radiative transport calculations of the solar photosphere. each of the four categories adopted are based on magnetic field and continuum intensity limits determined from examining three - dimensional magnetohydrodynamic simulations with an average magnetic flux of $ 200 \ mathrm { g } $. using these four component line profiles we accurately reconstruct granulation profiles, produced from modelling 12 x 12 mm $ ^ 2 $ areas on the solar surface, to within $ \ sim \ pm $ 20 cm s $ ^ { - 1 } $ on a $ \ sim $ 100 m s $ ^ { - 1 } $ granulation signal. we have also successfully reconstructed granulation profiles from a $ 50 \ mathrm { g } $ simulation using the parameterised line profiles from the $ 200 \ mathrm { g } $ average magnetic field simulation. this test demonstrates applicability of the characterisation to a range of magnetic stellar activity levels. | arxiv:1212.0236 |
we analyze the position of the two populations of blue stragglers in the globular cluster m30 in the hertzsprung - russell diagram. both populations of blue stragglers are brighter than the cluster ' s turn - off, but one population ( the blue blue - stragglers ) align along the zero - age main - sequence whereas the ( red ) population is elevated in brightness ( or colour ) by $ \ sim 0. 75 $ mag. based on stellar evolution and merger simulations we argue that the red population, which composes about 40 \ % of the blue stragglers in m 30, is formed at a constant rate of $ \ sim 2. 8 $ blue stragglers per gyr over the last $ \ sim 10 $ gyr. the blue population is formed in a burst that started $ \ sim 3. 2 $ gyr ago at a peak rate of $ 30 $ blue stragglers per gyr $ ^ { - 1 } $ with an e - folding time scale of $ 0. 93 $ gyr. we speculate that the burst resulted from the core collapse of the cluster at an age of about 9. 8 gyr, whereas the constantly formed population is the result of mass transfer and mergers through binary evolution. in that case about half the binaries in the cluster effectively result in a blue straggler. | arxiv:1811.00058 |
this paper is a survey of two kinds of " compressed " proof schemes, the \ emph { matrix method } and \ emph { proof nets }, as applied to a variety of logics ranging along the substructural hierarchy from classical all the way down to the nonassociative lambek system. a novel treatment of proof nets for the latter is provided. descriptions of proof nets and matrices are given in a uniform notation based on sequents, so that the properties of the schemes for the various logics can be easily compared. | arxiv:1203.4912 |
using an integrable discrete dirac operator, we construct a discrete version of the weierstrass representation of time - like surfaces parametrized along isotropic directions in $ r ^ { 2, 1 } $, $ r ^ { 3, 1 } $ and $ r ^ { 2, 2 } $. the corresponding discrete surfaces have isotropic edges. we show that any discrete surface satisfying a general monotonicity condition and having isotropic edges admits such a representation. | arxiv:0907.0688 |
simultaneous localization and mapping ( slam ) based on laser sensors has been widely adopted by mobile robots and autonomous vehicles. these slam systems are required to support accurate localization with limited computational resources. in particular, point cloud registration, i. e., the process of matching and aligning multiple lidar scans collected at multiple locations in a global coordinate framework, has been deemed as the bottleneck step in slam. in this paper, we propose a feature filtering algorithm, pfilter, that can filter out invalid features and can thus greatly alleviate this bottleneck. meanwhile, the overall registration accuracy is also improved due to the carefully curated feature points. we integrate pfilter into the well - established scan - to - map lidar odometry framework, f - loam, and evaluate its performance on the kitti dataset. the experimental results show that pfilter can remove about 48. 4 % of the points in the local feature map and reduce feature points in scan by 19. 3 % on average, which save 20. 9 % processing time per frame. in the mean time, we improve the accuracy by 9. 4 %. | arxiv:2208.14848 |
the time variation of the gravitational constant g in the recently discussed large number cosmologies accounts for the galactic rotational velocity curves without invoking dark matter and also for effects like the precession of the perhelion of mercury. | arxiv:physics/9904022 |
in this paper we prove that any degree $ d $ deformation of a generic logarithmic polynomial differential equation with a persistent center must be logarithmic again. this is a generalization of ilyashenko ' s result on hamiltonian differential equations. the main tools are picard - lefschetz theory of a polynomial with complex coefficients in two variables, specially the gusein - zade / a ' campo ' s theorem on calculating the dynkin diagram of the polynomial, and the action of gauss - manin connection on the so called brieskorn lattice / petrov module of the polynomial. some applications on the cyclicity of cycles and the bautin ideals will be given. | arxiv:math/0205068 |
indonesia is rich in languages and scripts. however, most nlp progress has been made using romanized text. in this paper, we present nusaaksara, a novel public benchmark for indonesian languages that includes their original scripts. our benchmark covers both text and image modalities and encompasses diverse tasks such as image segmentation, ocr, transliteration, translation, and language identification. our data is constructed by human experts through rigorous steps. nusaaksara covers 8 scripts across 7 languages, including low - resource languages not commonly seen in nlp benchmarks. although unsupported by unicode, the lampung script is included in this dataset. we benchmark our data across several models, from llms and vlms such as gpt - 4o, llama 3. 2, and aya 23 to task - specific systems such as pp - ocr and langid, and show that most nlp technologies cannot handle indonesia ' s local scripts, with many achieving near - zero performance. | arxiv:2502.18148 |
despite exhibiting very high theoretical data rates, in practice, the performance of lte - u / laa and wifi networks is severely limited under cross - technology coexistence scenarios in the unlicensed 5ghz band. as a remedy, recent research shows the need for collaboration and coordination among co - located networks. however, enabling such collaboration requires an information exchange that is hard to realize due to completely incompatible network protocol stacks. we propose ofdmfi, the first cross - technology communication scheme that enables direct bidirectional over - the - air communication between lte - u / laa and wifi with minimal overhead to their legacy transmissions. requiring neither hardware nor firmware changes in commodity technologies, ofdmfi leverages the standard - compliant possibility of generating message - bearing power patterns, similar to punched cards from the early days of computers, in the time - frequency resource grid of an ofdm transmitter which can be cross - observed and decoded by a heterogeneous ofdm receiver. as a proof - of - concept, we have designed and implemented a prototype using commodity devices and sdr platforms. our comprehensive evaluation reveals that ofdmfi achieves robust bidirectional ctc between both systems with a data rate of up to 84kbps, which is more than 125x faster than state - of - the - art. | arxiv:1912.04093 |
thanks to rapid technological advances in the internet of things ( iot ), a smart public safety ( sps ) system has become feasible by integrating heterogeneous computing devices to collaboratively provide public protection services. while a service oriented architecture ( soa ) has been adopted by iot and cyber - physical systems ( cps ), it is difficult for a monolithic architecture to provide scalable and extensible services for a distributed iot based sps system. furthermore, traditional security solutions rely on a centralized authority, which can be a performance bottleneck or single point failure. inspired by microservices architecture and blockchain technology, this paper proposes a blockchain - enabled decentralized microservices architecture for smart public safety ( blendmas ). within a permissioned blockchain network, a microservices based security mechanism is introduced to secure data access control in an sps system. the functionality of security services are decoupled into separate containerized microservices that are built using a smart contract, and deployed on edge and fog computing nodes. an extensive experimental study verified that the proposed blendmas is able to offer a decentralized, scalable and secured data sharing and access control to distributed iot based sps system. | arxiv:1902.10567 |
a function on an algebra is congruence preserving if, for any congruence, it maps congruent elements to congruent elements. we show that, on a free monoid generated by at least 3 letters, a function from the free monoid into itself is congruence preserving % nonmonogenic if and only if it is of the form $ x \ mapsto w _ 0 x w _ 1 \ cdots w _ { n - 1 } x w _ n $ for some finite sequence of words $ w _ 0, \ ldots, w _ n $. we generalize this result to functions of arbitrary arity. this shows that a free monoid with at least three generators is a ( noncommutative ) affine complete algebra. up to our knowledge, it is the first ( nontrivial ) case of a noncommutative affine complete algebra. | arxiv:1609.01144 |
metal - oxide sensors are widely used due to their sensitivities to different types of gaseous, and these sensors are suitable for long - term applications, even in the presence of corrosive environments. however, the microscopic mechanisms with quantum effects, which are required to understand the gas - oxide interactions are not well developed despite the oxide sensors potential applications in numerous fields, namely, medicine ( breath - sensors ), engineering ( gas - sensors ) and food processing ( odor - sensors ). here, we develop a rigorous theoretical strategy based on the ionization energy theory ( iet ) to unambiguously explain why and how a certain gas molecule intrinsically prefers a particular oxide surface. we make use of the renormalized ionic displacement polarizability functional derived from the iet to show that the gas / surface interaction strength ( sensing sensitivity ) between an oxide surface and an isolated gas molecule can be predicted from the polarizability of these two systems. such predictions are extremely important for the development of health monitoring bio - sensors, as well as to select the most suitable oxide to detect a particular gas with optimum sensitivity. | arxiv:1003.4625 |
image registration is an essential step in many medical image analysis tasks. traditional methods for image registration are primarily optimization - driven, finding the optimal deformations that maximize the similarity between two images. recent learning - based methods, trained to directly predict transformations between two images, run much faster, but suffer from performance deficiencies due to model generalization and the inefficiency in handling individual image specific deformations. here we present a new neural net based image registration framework, called nir ( neural image registration ), which is based on optimization but utilizes deep neural nets to model deformations between image pairs. nir represents the transformation between two images with a continuous function implemented via neural fields, receiving a 3d coordinate as input and outputting the corresponding deformation vector. nir provides two ways of generating deformation field : directly output a displacement vector field for general deformable registration, or output a velocity vector field and integrate the velocity field to derive the deformation field for diffeomorphic image registration. the optimal registration is discovered by updating the parameters of the neural field via stochastic gradient descent. we describe several design choices that facilitate model optimization, including coordinate encoding, sinusoidal activation, coordinate sampling, and intensity sampling. experiments on two 3d mr brain scan datasets demonstrate that nir yields state - of - the - art performance in terms of both registration accuracy and regularity, while running significantly faster than traditional optimization - based methods. | arxiv:2206.03111 |
given spherically symmetric characteristic initial data for the einstein - scalar field system with a positive cosmological constant, we provide a criterion, in terms of the dimensionless size and dimensionless renormalized mass content of an annular region of the data, for the formation of a future trapped surface. this corresponds to an extension of christodoulou ' s classical criterion by the inclusion of the cosmological term. | arxiv:2005.03434 |
in this paper, a unified approach is proposed to derive the exact local asymptotic power for panel unit root tests, which is one of the most important issues in nonstationary panel data literature. two most widely used panel unit root tests known as levin - lin - chu ( llc, levin, lin and chu ( 2002 ) ) and im - pesaran - shin ( ips, im, pesaran and shin ( 2003 ) ) tests are systematically studied for various situations to illustrate our method. our approach is characteristic function based, and can be used directly in deriving the moments of the asymptotic distributions of these test statistics under the null and the local - to - unity alternatives. for the llc test, the approach provides an alternative way to obtain the results that can be derived by the existing method. for the ips test, the new results are obtained, which fills the gap in the literature where few results exist, since the ips test is non - admissible. moreover, our approach has the advantage in deriving edgeworth expansions of these tests, which are also given in the paper. the simulations are presented to illustrate our theoretical findings. | arxiv:1710.02944 |
we present phydeformer, a new deformation method for high - quality garment mesh registration. it operates in two phases : in the first phase, a garment grading is performed to achieve a coarse 3d alignment between the mesh template and the target mesh, accounting for proportional scaling and fit ( e. g. length, size ). then, the graded mesh is refined to align with the fine - grained details of the 3d target through an optimization coupled with the jacobian - based deformation framework. both quantitative and qualitative evaluations on synthetic and real garments highlight the effectiveness of our method. | arxiv:2501.10455 |
we present a new parametric lens model for the g165. 7 + 67. 0 galaxy cluster, which was discovered with $ planck $ through its bright submillimeter flux, originating from a pair of extraordinary dusty star - forming galaxies ( dsfgs ) at $ z \ approx 2. 2 $. using jwst and interferometric mm / radio observations, we characterize the intrinsic physical properties of the dsfgs, which are separated by only $ \ sim 1 ^ { \ prime \ prime } $ ( 8 kpc ) and a velocity difference $ \ delta v \ lesssim 600 ~ { \ rm km } ~ { \ rm s } ^ { - 1 } $ in the source plane, and thus likely undergoing a major merger. boasting intrinsic star formation rates $ { \ rm sfr } _ { \ rm ir } = 320 \ pm 70 $ and $ 400 \ pm 80 ~ m _ \ odot ~ { \ rm yr } ^ { - 1 } $, stellar masses $ { \ rm log } [ m _ \ star / m _ \ odot ] = 10. 2 \ pm 0. 1 $ and $ 10. 3 \ pm 0. 1 $, and dust attenuations $ a _ v = 1. 5 \ pm 0. 3 $ and $ 1. 2 \ pm 0. 3 $, they are remarkably similar objects. we perform spatially - resolved pixel - by - pixel sed fitting using rest - frame near - uv to near - ir imaging from jwst / nircam for both galaxies, resolving some stellar structures down to 100 pc scales. based on their resolved specific sfrs and $ uvj $ colors, both dsfgs are experiencing significant galaxy - scale star formation events. if they are indeed interacting gravitationally, this strong starburst could be the hallmark of gas that has been disrupted by an initial close passage. in contrast, the host galaxy of the recently discovered triply - imaged sn h0pe has a much lower sfr than the dsfgs, and we present evidence for the onset of inside - out quenching and large column densities of dust even in regions of low specific sfr. based on the intrinsic sfrs of the dsfgs inferred from uv through fir sed modeling, this pair of objects alone is predicted to yield an observable $ 1. 1 \ pm 0. 2 ~ { \ rm ccsne ~ yr } ^ { - | arxiv:2404.08058 |
for reaction - diffusion equations in irregular domain with moving boundaries, the numerical stability constraints from the reaction and diffusion terms often require very restricted time step size, while complex geometries may lead to difficulties in accuracy when discretizing the high - order derivatives on grid points near the boundary. it is very challenging to design numerical methods that can efficiently and accurately handle both difficulties. applying an implicit scheme may be able to remove the stability constraints on the time step, however, it usually requires solving a large global system of nonlinear equations for each time step, and the computational cost could be significant. integration factor ( if ) or exponential differencing time ( etd ) methods are one of the popular methods for temporal partial differential equations ( pdes ) among many other methods. in our paper, we couple etd methods with an embedded boundary method to solve a system of reaction - diffusion equations with complex geometries. in particular, we rewrite all etd schemes into a linear combination of specific { \ phi } - functions and apply one start - of - the - art algorithm to compute the matrix - vector multiplications, which offers significant computational advantages with adaptive krylov subspaces. in addition, we extend this method by incorporating the level set method to solve the free boundary problem. the accuracy, stability, and efficiency of the developed method are demonstrated by numerical examples. | arxiv:2209.15095 |
we revisit the oblivious transfer ( ot ) capacities of noisy channels against the passive adversary, which have been identified only for a limited class of channels. in the literature, the general construction of oblivious transfer has been known only for generalized erasure channels ( gecs ) ; for other channels, we first convert a given channel to a gec via alphabet extension and erasure emulation, and then apply the general construction for gec. in this paper, we derive an improved lower bound on the ot capacity of the binary symmetric channel ( bsc ) and binary symmetric erasure channel ( bsec ) by proposing a new protocol ; by using interactive communication between the sender and the receiver, our protocol emulates erasure events recursively in multiple rounds. we also discuss a potential necessity of multiple rounds interactive communication to attain the ot capacity. | arxiv:2401.14965 |
applying gaussian splatting to perception tasks for 3d scene understanding is becoming increasingly popular. most existing works primarily focus on rendering 2d feature maps from novel viewpoints, which leads to an imprecise 3d language field with outlier languages, ultimately failing to align objects in 3d space. by utilizing masked images for feature extraction, these approaches also lack essential contextual information, leading to inaccurate feature representation. to this end, we propose a language - embedded surface field ( langsurf ), which accurately aligns the 3d language fields with the surface of objects, facilitating precise 2d and 3d segmentation with text query, widely expanding the downstream tasks such as removal and editing. the core of langsurf is a joint training strategy that flattens the language gaussian on the object surfaces using geometry supervision and contrastive losses to assign accurate language features to the gaussians of objects. in addition, we also introduce the hierarchical - context awareness module to extract features at the image level for contextual information then perform hierarchical mask pooling using masks segmented by sam to obtain fine - grained language features in different hierarchies. extensive experiments on open - vocabulary 2d and 3d semantic segmentation demonstrate that langsurf outperforms the previous state - of - the - art method langsplat by a large margin. as shown in fig. 1, our method is capable of segmenting objects in 3d space, thus boosting the effectiveness of our approach in instance recognition, removal, and editing, which is also supported by comprehensive experiments. \ url { https : / / langsurf. github. io }. | arxiv:2412.17635 |
the classical platonist / formalist dilemma in philosophy of mathematics can be expressed in lay terms as a deceptively naive question : \ emph { is new mathematics discovered or invented? using examples from my own mathematical work during the coronavirus lockdown, i argue that there is also a third way : new mathematics can also be inherited. and entering into possession, making it your own, could be great fun. | arxiv:2103.04101 |
introduction : skateboarding is one of the most popular cultures in brazil, with more than 8. 5 million skateboarders. nowadays, the discipline of street skating has gained recognition among other more classical sports and awaits its debut at the tokyo 2020 summer olympic games. this study aimed to explore the state - of - the - art for inertial measurement unit ( imu ) use in skateboarding trick detection, and to develop new classification methods using supervised machine learning and artificial neural networks ( ann ). methods : state - of - the - art knowledge regarding motion detection in skateboarding was used to generate 543 artificial acceleration signals through signal modeling, corresponding to 181 flat ground tricks divided into five classes ( nollie, nshov, flip, shov, ollie ). the classifier consisted of a multilayer feed - forward neural network created with three layers and a supervised learning algorithm ( backpropagation ). results : the use of anns trained specifically for each measured axis of acceleration resulted in error percentages inferior to 0. 05 %, with a computational efficiency that makes real - time application possible. conclusion : machine learning can be a useful technique for classifying skateboarding flat ground tricks, assuming that the classifiers are properly constructed and trained, and the acceleration signals are preprocessed correctly. | arxiv:2005.04186 |
in this note we provide some applications of l \ " owenheim - skolem cardinals introduced in \ cite { u }. | arxiv:2004.01515 |
root cause analysis ( rca ) plays a pivotal role in the incident diagnosis process for cloud services, requiring on - call engineers to identify the primary issues and implement corrective actions to prevent future recurrences. improving the incident rca process is vital for minimizing service downtime, customer impact and manual toil. recent advances in artificial intelligence have introduced state - of - the - art large language models ( llms ) like gpt - 4, which have proven effective in tackling various aiops problems, ranging from code authoring to incident management. nonetheless, the gpt - 4 model ' s immense size presents challenges when trying to fine - tune it on user data because of the significant gpu resource demand and the necessity for continuous model fine - tuning with the emergence of new data. to address the high cost of fine - tuning llm, we propose an in - context learning approach for automated root causing, which eliminates the need for fine - tuning. we conduct extensive study over 100, 000 production incidents, comparing several large language models using multiple metrics. the results reveal that our in - context learning approach outperforms the previous fine - tuned large language models such as gpt - 3 by an average of 24. 8 \ % across all metrics, with an impressive 49. 7 \ % improvement over the zero - shot model. moreover, human evaluation involving actual incident owners demonstrates its superiority over the fine - tuned model, achieving a 43. 5 \ % improvement in correctness and an 8. 7 \ % enhancement in readability. the impressive results demonstrate the viability of utilizing a vanilla gpt model for the rca task, thereby avoiding the high computational and maintenance costs associated with a fine - tuned model. | arxiv:2401.13810 |
inverse melting is the phenomenon, observed in both helium isotopes, by which a crystal melts when cooled at constant pressure. i investigate discrete - space analogs of inverse melting by means of two instances of a triangular - lattice - gas system endowed with a soft - core repulsion and a short - ranged attraction. to reconstruct the phase diagram, i use both transfer - matrix and monte carlo methods, as well as low - temperature series expansions. in one case, a phase behavior reminiscent of helium emerges, with a loose - packed phase ( which is solid - like for low temperatures and liquid - like for high temperatures ) extending down to zero temperature for low pressures and the possibility of melting the close - packed solid by isobaric cooling. at variance with previous model studies of inverse melting, the driving mechanism of the present phenomenon is mainly geometrical, related to the larger free - energy cost of a ` ` vacancy ' ' in the loose - packed solid than in the close - packed one. | arxiv:cond-mat/0701369 |
the eigenstate thermalization hypothesis ( eth ) posits that the reduced density matrix for a subsystem corresponding to an excited eigenstate is " thermal. " here we expound on this hypothesis by asking : for which class of operators, local or non - local, is eth satisfied? we show that this question is directly related to a seemingly unrelated question : is the hamiltonian of a system encoded within a single eigenstate? we formulate a strong form of eth where in the thermodynamic limit, the reduced density matrix of a subsystem corresponding to a pure, finite energy density eigenstate asymptotically becomes equal to the thermal reduced density matrix, as long as the subsystem size is much less than the total system size, irrespective of how large the subsystem is compared to any intrinsic length scale of the system. this allows one to access the properties of the underlying hamiltonian at arbitrary energy densities / temperatures using just a $ \ textit { single } $ eigenstate. we provide support for our conjecture by performing an exact diagonalization study of a non - integrable 1d lattice quantum model with only energy conservation. in addition, we examine the case in which the subsystem size is a finite fraction of the total system size, and find that even in this case, a large class of operators continue to match their canonical expectation values. specifically, the von neumann entanglement entropy equals the thermal entropy as long as the subsystem is less than half the total system. we also study, both analytically and numerically, a particle number conserving model at infinite temperature which substantiates our conjectures. | arxiv:1503.00729 |
we report the discovery of rave j203843. 2 - 002333, a bright ( v = 12. 73 ), very metal - poor ( [ fe / h ] = - 2. 91 ), r - process - enhanced ( [ eu / fe ] = + 1. 64 and [ ba / eu ] = - 0. 81 ) star selected from the rave survey. this star was identified as a metal - poor candidate based on its medium - resolution ( r ~ 1, 600 ) spectrum obtained with the kpno / mayall telescope, and followed - up with high - resolution ( r ~ 66, 000 ) spectroscopy with the magellan / clay telescope, allowing for the determination of elemental abundances for 24 neutron - capture elements, including thorium and uranium. rave j2038 - 0023 is only the fourth metal - poor star with a clearly measured u abundance. the derived chemical - abundance pattern exhibits good agreement with those of other known highly r - process - enhanced stars, and evidence in hand suggests that it is not an actinide - boost star. age estimates were calculated using th / x and u / x abundance ratios, yielding a mean age of 13. 0 + / - 1. 1 gyr. | arxiv:1706.02934 |
we consider the evolution of relativistic perturbations in the einstein - de sitter cosmological model, including second - order effects. the perturbations are considered in two different settings : the widely used synchronous gauge and the poisson ( generalized longitudinal ) one. since, in general, perturbations are gauge dependent, we start by considering gauge transformations at second order. next, we give the evolution of perturbations in the synchronous gauge, taking into account both scalar and tensor modes in the initial conditions. using the second - order gauge transformation previously defined, we are then able to transform these perturbations to the poisson gauge. the most important feature of second - order perturbation theory is mode - mixing, which here also means, for instance, that primordial density perturbations act as a source for gravitational waves, while primordial gravitational waves give rise to second - order density fluctuations. possible applications of our formalism range from the study of the evolution of perturbations in the mildly non - linear regime to the analysis of secondary anisotropies of the cosmic microwave background. | arxiv:astro-ph/9707278 |
this paper is an elitr system submission for the non - native speech translation task at iwslt 2020. we describe systems for offline asr, real - time asr, and our cascaded approach to offline slt and real - time slt. we select our primary candidates from a pool of pre - existing systems, develop a new end - to - end general asr system, and a hybrid asr trained on non - native speech. the provided small validation set prevents us from carrying out a complex validation, but we submit all the unselected candidates for contrastive evaluation on the test set. | arxiv:2006.03331 |
z - disks are complex structures that delineate repeating sarcomeres in striated muscle. they play significant roles in cardiomyocytes such as providing mechanical stability for the contracting sarcomere, cell signalling and autophagy. changes in z - disk architecture have been associated with impaired cardiac function. hence, there is a strong need to create tools to segment z - disks from microscopy images, that overcome traditional limitations such as variability in image brightness and staining technique. in this study, we apply deep learning based segmentation models to extract z - disks in images of striated muscle tissue. we leverage a novel airyscan confocal dataset, which comprises high resolution images of z - disks of healthy heart tissue, stained with affimers for specific z - disk proteins. we employed an interactive labelling tool, ilastik to obtain ground truth segmentation masks and use the resulting data set to train and evaluate the performance of several state - of - the - art segmentation networks. on the test set, unet + + achieves best segmentation performance for z - disks in cardiomyocytes, with an average dice score of 0. 91 and outperforms other established segmentation methods including unet, fpn, deeplabv3 + and pix2pix. however, pix2pix demonstrates improved generalisation, when tested on an additional dataset of cardiomyocytes with a titin mutation. this is the first study to demonstrate that automated machine learning - based segmentation approaches may be used effectively to segment z - disks in confocal microscopy images. automated segmentation approaches and predicted segmentation masks could be used to derive morphological features of z - disks ( e. g. width and orientation ), and subsequently, to quantify disease - related changes to cardiac microstructure. | arxiv:2401.13472 |
current vhr ( very high resolution ) satellite images enable the detailed monitoring of the earth and can capture the ongoing works of railway construction. in this paper, we present an integrated framework applied to monitoring the railway construction in china, using quickbird, gf - 2 and google earth vhr satellite images. we also construct a novel dcnns - based ( deep convolutional neural networks ) semantic segmentation network to label the temporary works such as borrow & spoil area, camp, beam yard and esas ( environmental sensitive areas ) such as resident houses throughout the whole railway construction project using vhr satellite images. in addition, we employ hed edge detection sub - network to refine the boundary details and attention cross entropy loss function to fit the sample class disequilibrium problem. our semantic segmentation network is trained on 572 vhr true color images, and tested on the 15 quickbird true color images along ruichang - jiujiang railway during 2015 - 2017. the experiment results show that compared with the existing state - of - the - art approach, our approach has obvious improvements with an overall accuracy of more than 80 %. | arxiv:1908.11080 |
to study a possible effect of transverse fluctuations of a stripe in a 2d antiferromagnet on its charge dynamics, we identify elementary excitations of a weakly doped domain wall in the hubbard model. hartree - fock numerics and analysis of fermion zero modes suggest that for u > = 3t charged excitations are mobile holons, q = 1, s = 0. each holon resides on a kink in the position of the domain wall. we construct a simple model in which transverse stripe dynamics is induced solely by motion of the holons. in the absence of spin excitations ( spinons, q = 0, s = 1 / 2 ), stripe fluctuations do not suppress a tendency to form a global charge - density order. | arxiv:cond-mat/9907472 |
the thesis investigates the utilization of memristive and memcapacitive crossbar arrays in low - power machine learning accelerators, offering a comprehensive co - design framework for deep neural networks ( dnn ). the model, implemented through a hybrid python and pytorch approach, accounts for various non - idealities, achieving exceptional training accuracies of 90. 02 % and 91. 03 % for the cifar - 10 dataset with memristive and memcapacitive crossbar arrays on an 8 - layer vgg network. additionally, the thesis introduces a novel approach to emulate meminductor devices using operational transconductance amplifiers ( ota ) and capacitors, showcasing adjustable behavior. transistor - level simulations in 180 nm cmos technology, operating at 60 mhz, demonstrate the proposed meminductor emulator ' s viability with a power consumption of 0. 337 mw. the design is further validated in neuromorphic circuits and cnn accelerators, achieving training and testing accuracies of 91. 04 % and 88. 82 %, respectively. notably, the exclusive use of mos transistors ensures the feasibility of monolithic ic fabrication. this research significantly contributes to the exploration of advanced hardware solutions for efficient and high - performance machine - learning applications. | arxiv:2403.03002 |
recently, short video platforms have achieved rapid user growth by recommending interesting content to users. the objective of the recommendation is to optimize user retention, thereby driving the growth of dau ( daily active users ). retention is a long - term feedback after multiple interactions of users and the system, and it is hard to decompose retention reward to each item or a list of items. thus traditional point - wise and list - wise models are not able to optimize retention. in this paper, we choose reinforcement learning methods to optimize the retention as they are designed to maximize the long - term performance. we formulate the problem as an infinite - horizon request - based markov decision process, and our objective is to minimize the accumulated time interval of multiple sessions, which is equal to improving the app open frequency and user retention. however, current reinforcement learning algorithms can not be directly applied in this setting due to uncertainty, bias, and long delay time incurred by the properties of user retention. we propose a novel method, dubbed rlur, to address the aforementioned challenges. both offline and live experiments show that rlur can significantly improve user retention. rlur has been fully launched in kuaishou app for a long time, and achieves consistent performance improvement on user retention and dau. | arxiv:2302.01724 |
integrable equations in ( $ 1 + 1 $ ) dimensions have their own higher order integrable equations, like the kdv, mkdv and nls hierarchies etc. in this paper we consider whether integrable equations in ( $ 2 + 1 $ ) dimensions have also the analogous hierarchies to those in ( $ 1 + 1 $ ) dimensions. explicitly is discussed the bogoyavlenskii - schiff ( bs ) equation. for the bs hierarchy, there appears an ambiguity in the painlev \ ' e test. nevertheless, it may be concluded that the bs hierarchy is integrable. | arxiv:solv-int/9802005 |
in the highly interconnected realm of internet of things, exchange of sensitive information raises severe privacy concerns. the laplace mechanism - - adding laplace - distributed artificial noise to sensitive data - - is one of the widely used methods of providing privacy guarantees within the framework of differential privacy. in this work, we present lipschitz privacy, a slightly tighter version of differential privacy. we prove that the laplace mechanism is optimal in the sense that it minimizes the mean - squared error for identity queries which provide privacy with respect to the $ \ ell _ { 1 } $ - norm. in addition to the $ \ ell _ { 1 } $ - norm which respects individuals ' participation, we focus on the use of the $ \ ell _ { 2 } $ - norm which provides privacy of high - dimensional data. a variation of the laplace mechanism is proven to have the optimal mean - squared error from the identity query. finally, the optimal mechanism for the scenario in which individuals submit their high - dimensional sensitive data is derived. | arxiv:1504.00065 |
recently, it has been shown that entropy can be used to sort brownian particles according to their size. in particular, a combination of a static and a time - dependent force applied on differently sized particles which are confined in an asymmetric periodic structure can be used to separate them efficiently, by forcing them to move in opposite directions. in this paper, we investigate the optimization of the performance of the ' entropic splitter '. specifically, the splitting mechanism and how it depends on the geometry of the channel, and the frequency and strength of the periodic forcing is analyzed. using numerical simulations, we demonstrate that a very efficient and fast separation with a practically 100 % purity can be achieved by a proper optimization of the control variables. the results of this work could be useful for a more efficient separation of dispersed phases such as dna fragments or colloids dependent on their size. | arxiv:1406.4708 |
these are the revised accepted papers from the 26th international symposium on graph drawing and network visualization ( gd 2018 ), barcelona, spain, september 26 - september 28, 2018. proceedings are also to be published by springer in the lecture notes in computer science series. | arxiv:1809.03264 |
the role of the onsager reaction term ( ort ) is not yet well understood in frustrated coupled oscillator systems, since the thouless - anderson - palmer ( tap ) and replica methods cannot be directly applied to these non - equilibrium systems. in this paper, we consider two oscillator associative memory models, one with symmetric and one with asymmetric dilution of coupling. these two systems are ideal for evaluating the effect of the ort, because, with the exception of the ort, they have the same order parameter equations. we found that the two systems have identical macroscopic properties, except for the acceleration effect caused by the ort. this acceleration effect does not exist in any equilibrium system. | arxiv:cond-mat/9909048 |
machine learning ( ml ) models are increasingly used to support or substitute decision making. in applications where skilled experts are a limited resource, it is crucial to reduce their burden and automate decisions when the performance of an ml model is at least of equal quality. however, models are often pre - trained and fixed, while tasks arrive sequentially and their distribution may shift. in that case, the respective performance of the decision makers may change, and the deferral algorithm must remain adaptive. we propose a contextual bandit model of this online decision making problem. our framework includes budget constraints and different types of partial feedback models. beyond the theoretical guarantees of our algorithm, we propose efficient extensions that achieve remarkable performance on real - world datasets. | arxiv:2409.20489 |
generating sound effects for videos often requires creating artistic sound effects that diverge significantly from real - life sources and flexible control in the sound design. to address this problem, we introduce multifoley, a model designed for video - guided sound generation that supports multimodal conditioning through text, audio, and video. given a silent video and a text prompt, multifoley allows users to create clean sounds ( e. g., skateboard wheels spinning without wind noise ) or more whimsical sounds ( e. g., making a lion ' s roar sound like a cat ' s meow ). multifoley also allows users to choose reference audio from sound effects ( sfx ) libraries or partial videos for conditioning. a key novelty of our model lies in its joint training on both internet video datasets with low - quality audio and professional sfx recordings, enabling high - quality, full - bandwidth ( 48khz ) audio generation. through automated evaluations and human studies, we demonstrate that multifoley successfully generates synchronized high - quality sounds across varied conditional inputs and outperforms existing methods. please see our project page for video results : https : / / ificl. github. io / multifoley / | arxiv:2411.17698 |
it is well known that noncommutative geometry naturally emerges in the quantum hall states due to the presence of strong and constant magnetic fields. here, we discuss the underlying noncommutative geometry of quantum hall fluids in which the magnetic fields are spatially inhomogenoeus. we analyze these cases by employing symplectic geometry and fedosov ' s deformation quantization, which rely on symplectic connections and fedosov star - product. through this formalism, we unveil some new features concerning the static limit of the haldane ' s unimodular metric and the girvin - macdonald - platzman algebra of the density operators, which plays a central role in the fractional quantum hall effect. | arxiv:2304.04002 |
we investigate the competition of coherent and dissipative dynamics in many - body systems at continuous quantum transitions. we consider dissipative mechanisms that can be effectively described by lindblad equations for the density matrix of the system. the interplay between the critical coherent dynamics and dissipation is addressed within a dynamic finite - size scaling framework, which allows us to identify the regime where they develop a nontrivial competition. we analyze protocols that start from critical many - body ground states and put forward general dynamic scaling behaviors involving the hamiltonian parameters and the coupling associated with the dissipation. this scaling scenario is supported by a numerical study of the dynamic behavior of a one - dimensional lattice fermion gas undergoing a quantum ising transition in the presence of dissipative mechanisms such as local pumping, decaying, and dephasing. | arxiv:1905.03843 |
we outline the general construction of three - players games with incomplete information which fulfil the following conditions : ( i ) symmetry with respect to the exchange of the players ; ( ii ) the existence of the upper bound for total payoff resulting from bell inequalities ; ( iii ) the existence of both fair and unfair nash equilibria saturating this bound. conditions ( i ) $ \ div $ ( iii ) imply that we are dealing with conflicting interest games. an explicit example of such a game is given. a quantum counterpart of this game is considered which is obtained by keeping the same utilities but replacing classical advisor by a quantum one. it is shown that the quantum game possesses only fair equilibria with strictly higher payoffs than in the classical case. this implies that quantum nonlocality can be used to resolve a conflict between players. | arxiv:1609.03835 |
constructing high - quality generative models for 3d shapes is a fundamental task in computer vision with diverse applications in geometry processing, engineering, and design. despite the recent progress in deep generative modelling, synthesis of finely detailed 3d surfaces, such as high - resolution point clouds, from scratch has not been achieved with existing approaches. in this work, we propose to employ the latent - space laplacian pyramid representation within a hierarchical generative model for 3d point clouds. we combine the recently proposed latent - space gan and laplacian gan architectures to form a multi - scale model capable of generating 3d point clouds at increasing levels of detail. our evaluation demonstrates that our model outperforms the existing generative models for 3d point clouds. | arxiv:1912.06466 |
in this paper, we found within the framework of perturbative qcd, that in deuteron - deuteron scattering the bose - einstein correlations due to two parton showers production, induce azimuthal angle correlations, with three correlation lengths : the size of the deuteron ( $ r _ d $ ), the proton radius ( $ r _ n $ ), and the size of the bfkl pomeron which, is closely related to the saturation momentum ( $ r _ c \ sim 1 / q _ s $ ). these correlations are independent of the values of rapidities of the produced gluons ( long range rapidity correlations ), for large rapidities ( $ \ bas | y _ 1 - y _ 2 | \ geq 1 $ ), and have no symmetry with respect to $ \ phi \ to \ pi - \ phi $ ( $ \ vec { p } _ { t1 } \ to - \ vec { p } _ { t1 } $ ). therefore, they give rise to $ v _ n $ for all values of $ n $, not only even values. the contributions with the correlation length $ r _ d $ and $ r _ n $ crucially depend on the non - perturbative contributions, and to obtain estimates of their values, requiries a lot of modeling, while the correlations with $ r _ c \ sim 1 / q _ s $ have a perturbative qcd origin, and can be estimated in the colorglass condensate ( cgc ) approach. | arxiv:1611.01653 |
whether or not anomalies in the thermal conductivity in insulating cuprates can be attributed to antiferromagnetic order and magnons in a 2d mott insulator remains an intriguing open question. to shed light on this issue, we investigate the thermal conductivity $ \ kappa $ and its relationship with the specific heat $ c _ v $ in the half - filled 2d single - band hubbard model, using the numerically exact determinant quantum monte carlo algorithm and maximum entropy analytic continuation. at low temperatures where the charge degrees of freedom are gapped - out and $ c _ v $ exhibits a clear magnon peak, we observe that thermal conductivity $ \ kappa $ also tends to form a peak at similar temperatures. reducing temperature further produces a sharp upturn in $ \ kappa $, associated with an increasing mean - free path. we identify this as the high - temperature side of the anomalous peak in insulating cuprates, where the mean - free path eventually is cut - off by other scattering effects, including phonons, disorder, and physical size. different scattering effects in our model are identified and analyzed in the thermal diffusivity. | arxiv:2109.01119 |
we provide a prescription for constructing hamiltonians representing the low energy physics of correlated electron materials with dynamically screened coulomb interactions. the key feature is a renormalization of the hopping and hybridization parameters by the processes that lead to the dynamical screening. the renormalization is shown to be non - negligible for various classes of correlated electron materials. the bandwidth reduction effect is necessary for connecting models to materials behavior and for making quantitative predictions for low - energy properties of solids. | arxiv:1204.4900 |
in leader - follower multi - agent networks with switching topologies, choosing a subset of agents as leaders is a critical step to achieve desired performances. in this paper, we concentrate on the problem of selecting a minimum - size set of leaders that ensure the tracking of a reference signal in a highorder linear multi - agent network with a set of given topology dependent dwell time ( tddt ). first, we derive a sufficient condition that guarantees the states of all agents converging to an expected state trajectory. second, by exploiting submodular optimization method, we formulate the problem of identifying a minimal leader set which satisfies the proposed sufficient condition. third, we present an algorithm with the provable optimality bound to solve the formulated problem. finally, several numerical examples are provided to verify the effectiveness of the designed selection scheme. | arxiv:1912.06019 |
the need for flexible, low - overhead virtualization is evident on many fronts ranging from high - density cloud servers to mobile devices. during the past decade os - level virtualization has emerged as a new, efficient approach for virtualization, with implementations in multiple different unix - based systems. despite its popularity, there has been no systematic study of os - level virtualization from the point of view of security. in this report, we conduct a comparative study of several os - level virtualization systems, discuss their security and identify some gaps in current solutions. | arxiv:1407.4245 |
in this paper, we shall prove that space - like surfaces with bounded mean curvature functions in real analytic lorentzian 3 - manifolds can change their causality to time - like surfaces only if the mean curvature functions tend to zero. moreover, we shall show the existence of such surfaces with non - vanishing mean curvature and investigate their properties. | arxiv:1508.02514 |
this paper is concerned with multi - modal data fusion ( mmdf ) under unexpected modality failures in nonlinear non - gaussian dynamic processes. an efficient framework to tackle this problem is proposed. in particular, a notion termed modality " \ emph { usefulness } ", which takes a value of 1 or 0, is used for indicating whether the observation of this modality is useful or not. for $ n $ modalities involved, $ 2 ^ n $ combinations of their " \ emph { usefulness } " values exist. each combination defines one hypothetical model of the true data generative process. then the problem of concern is formalized as a task of nonlinear non - gaussian state filtering under model uncertainty, which is addressed by a dynamic model averaging ( dma ) based particle filter ( pf ) algorithm. this dma algorithm employs $ 2 ^ n $ models, while all models share the same state - transition function and a unique set of particle values. that makes its computational complexity only slightly larger than a single model based pf algorithm, especially for scenarios in which $ n $ is small. experimental results show that the proposed solution outperforms remarkably state - of - the - art methods. code and data are available at https : / / github. com / robinlau1981 / fusion. | arxiv:2105.06018 |
the rolling pad instability is caused by electromagnetic interactions in systems of horizontal layers with strongly different electric conductivities. we analyze the instability for a simplified model of a liquid metal battery ( lmb ), a promising device for large - scale stationary energy storage. numerical simulations of the flow and the dynamics of electromagnetically coupled interfacial waves are performed using openfoam. the work confirms the earlier conclusions that the instability is a significant factor affecting battery ' s operation. the critical role played by the ratio between the density differences across the two interfaces is elucidated. it is found that the ratio determines the stability characteristics and the type ( symmetrically or antisymmetrically coupled ) of dominant interfacial waves. | arxiv:1908.01884 |
real time seizure detection is a fundamental problem in computational neuroscience towards diagnosis and treatment ' s improvement of epileptic disease. we propose a real - time computational method for tracking and detection of epileptic seizures from raw neurophysiological recordings. our mechanism is based on the topological analysis of the sliding - window embedding of the time series derived from simultaneously recorded channels. we extract topological biomarkers from the signals via the computation of the persistent homology of time - evolving topological spaces. remarkably, the proposed biomarkers robustly captures the change in the brain dynamics during the ictal state. we apply our methods in different types of signals including scalp and intracranial electroencephalograms and magnetoencephalograms, in patients during interictal and ictal states, showing high accuracy in a range of clinical situations. | arxiv:2211.02523 |
with the recent emergence of foundation models trained on internet - scale data and demonstrating remarkable generalization capabilities, such foundation models have become more widely adopted, leading to an expanding range of application domains. despite this rapid proliferation, the trustworthiness of foundation models remains underexplored. specifically, the out - of - distribution detection ( oodd ) capabilities of large vision - language models ( lvlms ), such as gpt - 4o, which are trained on massive multi - modal data, have not been sufficiently addressed. the disparity between their demonstrated potential and practical reliability raises concerns regarding the safe and trustworthy deployment of foundation models. to address this gap, we evaluate and analyze the oodd capabilities of various proprietary and open - source lvlms. our investigation contributes to a better understanding of how these foundation models represent confidence scores through their generated natural language responses. furthermore, we propose a self - guided prompting approach, termed reflexive guidance ( reguide ), aimed at enhancing the oodd capability of lvlms by leveraging self - generated image - adaptive concept suggestions. experimental results demonstrate that our reguide enhances the performance of current lvlms in both image classification and oodd tasks. the lists of sampled images, along with the prompts and responses for each sample are available at https : / / github. com / daintlab / reguide. | arxiv:2410.14975 |
in this paper, we present texpro, a novel method for high - fidelity material generation for input 3d meshes given text prompts. unlike existing text - conditioned texture generation methods that typically generate rgb textures with baked lighting, texpro is able to produce diverse texture maps via procedural material modeling, which enables physical - based rendering, relighting, and additional benefits inherent to procedural materials. specifically, we first generate multi - view reference images given the input textual prompt by employing the latest text - to - image model. we then derive texture maps through a rendering - based optimization with recent differentiable procedural materials. to this end, we design several techniques to handle the misalignment between the generated multi - view images and 3d meshes, and introduce a novel material agent that enhances material classification and matching by exploring both part - level understanding and object - aware material reasoning. experiments demonstrate the superiority of the proposed method over existing sotas and its capability of relighting. | arxiv:2410.15891 |
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