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as part of our ongoing wolf - rayet ( wr ) magellanic cloud survey, we have discovered 13 new wrs. however, the most exciting outcome of our survey is not the number of new wrs, but their unique characteristics. eight of our discoveries appear to belong to an entirely new class of wrs. while one might naively classify these stars as wn3 + o3v binaries, such a pairing is unlikely. preliminary cmfgen modeling suggests physical parameters similar to early - type wns in the large magellanic cloud except with mass - loss rates three to five times lower and slightly higher temperatures. the evolution status of these stars remains an open question.
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arxiv:1507.07154
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let h, k be subgroups of g. we investigate the intersection properties of left and right cosets of these subgroups.
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arxiv:1304.6111
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high - speed photonic integrated circuits leveraging the thin - film lithium niobate ( tfln ) platform present a promising approach to address the burgeoning global data traffic demands. as a pivotal component, tfln - based electro - optic ( eo ) mach - zehnder modulators ( mzms ) should exhibit low driving voltage, broad operation bandwidth, high extinction ration, and low insertion loss. however, the pursuit of both maximal eo overlap integral and minimal microwave loss necessitates a fundamental compromise between driving voltage and operational bandwidth. here, we demonstrate high - performance tfln eo mzms constructed on a 12 - { \ mu } m - thick silica buried layer using periodic capacitively loaded traveling - wave electrodes. in contrast to their counterparts utilizing undercut etched silicon substrates or quartz substrates, our devices exhibit streamlined fabrication processes and enhanced modulation efficiency. notably, the fabricated mzms attains a high modulation efficiency of 1. 25 vcm in the telecom c - band, while maintaining a low eo roll - off of 1. 3 db at 67 ghz. our demonstration offers a pathway to achieving perfect group velocity matching and break the voltage - bandwidth limit in a simplified configuration suitable for volume fabrication, thereby laying foundational groundwork for the advancement of high - performance tfln mzms and benefiting the next - generation pics in optical telecommunication, signal processing and other applications.
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arxiv:2412.12556
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the configuration of the interplanetary magnetic field and features of the related ambient solar wind in the ecliptic and meridional plane are different. therefore, one can expect that the orientation of the flux - rope axis of a coronal mass ejection ( cme ) influences the propagation of the cme itself. however, the determination of the cme orientation, especially from image data, remains a challenging task to perform. this study aims to provide a reference to different cme orientation determination methods in the near - sun environment. also, it aims to investigate the non - radial flow in the sheath region of the interplanetary cme ( icme ) in order to provide the first proxy to relate the icme orientation with its propagation. we investigated 22 isolated cme - icme events in the period 2008 - 2015. we determined the cme orientation in the near - sun environment using the following : 1 ) a 3d reconstruction of the cme with the graduated cylindrical shell ( gcs ) model applied to coronagraphic images provided by the stereo and soho missions and ; 2 ) an ellipse fitting applied to single spacecraft data from soho / lasco c2 and c3 coronagraphs. in the near - earth environment, we obtained the orientation of the corresponding icme using in situ plasma and field data and also investigated the non - radial flow ( nrf ) in its sheath region. the ability of gcs and ellipse fitting to determine the cme orientation is found to be limited to reliably distinguish only between the high or low inclination of the events. most of the cme - icme pairs under investigation were found to be characterized by a low inclination. for the majority of cme - icme pairs, we obtain consistent estimations of the tilt from remote and in situ data. the observed nrfs in the sheath region show a greater y direction to z direction flow ratio for high - inclination events, indicating that the cme orientation could have an impact on the cme propagation.
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arxiv:2204.10112
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we propose a scenario for the formation of the pulsar with two white dwarfs ( wds ) triple system psr j0337 + 1715. in our scenario a close binary system is tidally and frictionally destroyed inside the envelope of a massive star that later goes through an accretion induced collapse ( aic ) and forms the neutron star ( ns ). the proposed scenario includes a new ingredient of a binary system that breaks - up inside a common envelope. we use the binary c software to calculate the post break - up evolution of the system, and show that both low mass stars end as helium wds. one of the two lower mass stars that ends further out, the tertiary star, transfers mass to the onemg wd remnant of the massive star, and triggers the aic. the inner low mass main sequence star evolves later, induces aic if the tertiary had not done it already, and spins - up the ns to form a millisecond pulsar. this scenario is not extremely sensitive to many of the parameters, such as the eccentricity of the tertiary star and the orbital separation of the secondary star after the low mass binary system breaks loose inside the envelope, and to the initial masses of these stars. the proposed scenario employs an efficient envelope removal by jets launched by the compact object immersed in the giant envelope, and the newly proposed grazing envelope evolution.
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arxiv:1501.06787
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we address the question of whether geometric conditions on the given data can be preserved by a solution in ( 1 ) the whitney extension problem, and ( 2 ) the brenner - fefferman - hochster - koll \ ' ar problem, both for $ \ mathcal c ^ m $ functions. our results involve a certain loss of differentiability. problem ( 2 ) concerns the solution of a system of linear equations $ a ( x ) g ( x ) = f ( x ) $, where $ a $ is a matrix of functions on $ \ mathbb r ^ n $, and $ f $, $ g $ are vector - valued functions. suppose the entries of $ a ( x ) $ are semialgebraic ( or, more generally, definable in a suitable o - minimal structure ). then we find $ r = r ( m ) $ such that, if $ f ( x ) $ is definable and the system admits a $ \ mathcal c ^ r $ solution $ g ( x ) $, then there is a $ \ mathcal c ^ m $ definable solution. likewise in problem ( 1 ), given a closed definable subset $ x $ of $ \ mathbb r ^ n $, we find $ r = r ( m ) $ such that if $ g : x \ to \ mathbb r $ is definable and extends to a $ \ mathcal c ^ r $ function on $ \ mathbb r ^ n $, then there is a $ \ mathcal c ^ m $ definable extension.
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arxiv:2010.13815
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finite difference schemes are the method of choice for solving nonlinear, degenerate elliptic pdes, because the barles - sougandis convergence framework [ barles and sougandidis, asymptotic analysis, 4 ( 3 ) : 271 - 283, 1991 ] provides sufficient conditions for convergence to the unique viscosity solution [ crandall, ishii and lions, bull. amer. math soc., 27 ( 1 ) : 1 - 67, 1992 ]. for anisotropic operators, such as the monge - ampere equation, wide stencil schemes are needed [ oberman, siam j. numer. anal., 44 ( 2 ) : 879 - 895 ]. the accuracy of these schemes depends on both the distances to neighbors, $ r $, and the angular resolution, $ d \ theta $. on uniform grids, the accuracy is $ \ mathcal o ( r ^ 2 + d \ theta ) $. on point clouds, the most accurate schemes are of $ \ mathcal o ( r + d \ theta ) $, by froese [ numerische mathematik, 138 ( 1 ) : 75 - 99, 2018 ]. in this work, we construct geometrically motivated schemes of higher accuracy in both cases : order $ \ mathcal o ( r + d \ theta ^ 2 ) $ on point clouds, and $ \ mathcal o ( r ^ 2 + d \ theta ^ 2 ) $ on uniform grids.
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arxiv:1807.05150
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aims. young, massive stars have been found at projected distances r < 0. 5 pc from supermassive black hole, sgr a * at the center of our galay. in recent years, increasing evidence has been found for the presence of young, massive stars also at r > 0. 5 pc. our goal in this work is a systematic search for young, massive star candidates throughout the entire region within r ~ 2. 5 pc of the black hole. methods. the main criterion for the photometric identification of young, massive early - type stars is the lack of co - absorption in the spectra. we used narrow - band imaging with vlt / isaac to search for young, massive stars within ~ 2. 5 pc of sgr a *. results. we have found 63 early - type star candidates at r < 2. 5 pc, with an estimated erroneous identification rate of only about 20 %. considering their k - band magnitudes and interstellar extinction, they are candidates for wolf - rayet stars, supergiants, or early o - type stars. of these, 31 stars are so far unknown young, massive star candidates, all of which lie at r > 0. 5pc. the surface number density profile of the young, massive star candidates can be well fit by a single power - law, with gamma = 1. 6 + - 0. 17 at r < 2. 5 pc, which is significantly steeper than that of the late - type giants that make up the bulk of the observable stars in the nsc. intriguingly, this power - law is consistent with the power - law that describes the surface density of young, massive stars in the same brightness range at r < 0. 5 pc. conclusions. the finding of a significant number of newly identified early - type star candidates at the galactic center suggests that young, massive stars can be found throughout the entire cluster which may require us to modify existing theories for star formation at the galactic center. follow - up studies are needed to improve the existing data and lay the foundations for a unified theory of star formation in the milky way ' s nsc.
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arxiv:1210.6125
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the transition metal ions doped with tio2 films are of magnetic properties at room temperatures and have stimulated many scientists to study other properties. the co - tio2 sandwich composite films have been recently grown on glass and silicon substrates by using alternately radio frequency reactive and direct current magnetron sputtering. the microstructural properties of these films were characterized with raman spectra and x - ray photoemission spectra ( xps ). it shows an anatase tio2 containing co nano - layer. optical absorption spectra have red shift with co nano - layer increasing, which originated from the quantum confinement and tunnel effects. magnetic properties show that the saturation magnetization, remanent magnetic induction and coercivity are about 4. 35 emu / g, 1. 02 emu / g and 569. 6 oe respectively for 12 nm co layer between the two tio2 layers.
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arxiv:cond-mat/0204419
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quasiparticle interference has been used frequently for the purpose of unraveling the electronic states in the vicinity of the fermi level as well as the nature of superconducting gap in the unconventional superconductors. using the metallic spin - density wave state of iron pnictides as an example, we demonstrate that the quasiparticle interference can also be used as a probe to provide crucial insight into the interplay of the electronic bandstructure and correlation effects in addition to bringing forth the essential features of electronic states in the vicinity of the fermi level. our study reveals that the features of quasiparticle interference pattern can help us narrowing down the interaction parameter window and choose a more realistic tight - binding model.
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arxiv:2503.01204
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we build upon some new ideas in direct transcription methods developed within the advanced concepts team to introduce two improvements to the sims - flanagan transcription for low - thrust trajectories. the obtained new algorithm is able to produce an operational trajectory accounting for the real spacecraft dynamics and adapting the segment duration on - line improving the final trajectory optimality.
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arxiv:1004.4539
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the nime conference traditionally focuses on interfaces for music and musical expression. in this paper we reverse this tradition to ask, can interfaces developed for music be successfully appropriated to non - musical applications? to help answer this question we designed and developed a new device, which uses interface metaphors borrowed from analogue synthesisers and audio mixing to physically control the intangible aspects of a large language model. we compared two versions of the device, with and without the audio - inspired augmentations, with a group of artists who used each version over a one week period. our results show that the use of audio - like controls afforded more immediate, direct and embodied control over the llm, allowing users to creatively experiment and play with the device over its non - mixer counterpart. our project demonstrates how cross - sensory metaphors can support creative thinking and embodied practice when designing new technological interfaces.
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arxiv:2504.13944
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the thin runback water films driven by the gas flow, the pressure gradient and the gravity on the iced aircraft surface are investigated in this paper. a three - dimensional film flow model based on finite volume method ( fvm ) and the lubrication theory is proposed to describe the flow. the depth - averaged velocity of the film is stored in cartesian coordinates to avoid the appearance of the metric tensors. the governing equations are discretized in the first layer structured grid cell which is selected as the grids for film flow. in order to verify this method, comparisons between numerical results and experimental results of ice shapes on naca 0012 airfoil and glc - 305 swept wing are presented, both showing a good agreement for rime and glaze ice condition. overall, this model shows great potential to model ice accretion reasonably under different icing conditions. besides, the present method doesn ' t require analytic metric terms, and can be easily coupled to existing finite volume solvers for logically cartesian meshes.
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arxiv:2204.08014
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in - context learning is a promising approach for offline reinforcement learning ( rl ) to handle online tasks, which can be achieved by providing task prompts. recent works demonstrated that in - context rl could emerge with self - improvement in a trial - and - error manner when treating rl tasks as an across - episodic sequential prediction problem. despite the self - improvement not requiring gradient updates, current works still suffer from high computational costs when the across - episodic sequence increases with task horizons. to this end, we propose an in - context decision transformer ( idt ) to achieve self - improvement in a high - level trial - and - error manner. specifically, idt is inspired by the efficient hierarchical structure of human decision - making and thus reconstructs the sequence to consist of high - level decisions instead of low - level actions that interact with environments. as one high - level decision can guide multi - step low - level actions, idt naturally avoids excessively long sequences and solves online tasks more efficiently. experimental results show that idt achieves state - of - the - art in long - horizon tasks over current in - context rl methods. in particular, the online evaluation time of our idt is \ textbf { 36 $ \ times $ } times faster than baselines in the d4rl benchmark and \ textbf { 27 $ \ times $ } times faster in the grid world benchmark.
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arxiv:2405.20692
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dna adsorption and naturation is modeled via two interacting flexible homopolymers coupled to a solid surface. dna denatures if the entropy gain for unbinding the two strands overcomes the loss of binding energy. when adsorbed to a surface, the entropy gain is smaller than in the bulk, leading to a stronger binding and, upon neglecting self - avoidance, absence of a denatured phase. now consider conditions where the binding potentials are too weak for naturation, and the surface potential too weak to adsorb single strands. in a variational approach it is shown that their combined action may lead to a naturated adsorbed phase. conditions for the absence of naturation and adsorption are derived too. the phase diagram is constructed qualitatively.
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arxiv:cond-mat/0512237
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we study a model of spontaneous wavefunction collapse for a free quantum particle. we analyze in detail the time evolution of the single - gaussian solution and the double - gaussian solution, showing how the reduction mechanism induces the localization of the wavefunction in space ; we also study the asymptotic behavior of the general solution. with an appropriate choice for the parameter $ \ lambda $ which sets the strength of the collapse mechanism, we prove that : i ) the effects of the reducing terms on the dynamics of microscopic systems are negligible, the physical predictions of the model being very close to those of standard quantum mechanics ; ii ) at the macroscopic scale, the model reproduces classical mechanics : the wavefunction of the center of mass of a macro - object behaves, with high accuracy, like a point moving in space according to newton ' s laws.
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arxiv:quant-ph/0410222
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we present a method to model photonic components in verilog - a by introducing bidirectional signaling through a single port. to achieve this, the concept of power waves and scattering parameters from electromagnetism are employed. as a consequence, one can simultaneously transmit forward and backward propagating waves on a single wire while also capturing realistic, measurement - backed response of photonic components in verilog - a. we demonstrate examples to show the efficacy of the proposed technique in accounting for critical effects in photonic integrated circuits such as fabry - perot cavity resonance, reflections to lasers, etc. our solution makes electronic - photonic co - simulation more intuitive and accurate.
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arxiv:2402.10971
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the mechanics of lower dimensional elastic structures depends strongly on the geometry of their stress - free state. elastic deformations separate into in - plane stretching and lower energy out - of - plane bending deformations. for elastic structures with a curved stress - free state, these two elastic modes are coupled within linear elasticity. we investigate the effect of that curvature - induced coupling on wave propagation in lower dimensional elastic structures, focusing on the simplest example - - a curved elastic rod. we find that the dispersion relation of the waves becomes gapped in the presence of finite curvature ; bending modes are absent below a frequency proportional to the curvature of the rod. by studying the scattering of undulatory waves off regions of uniform curvature, we find that undulatory waves with frequencies in the gap associated with the curved region tunnel through that curved region via conversion into compression waves. these results should be directly applicable to the spectrum and spatial distribution of phonon modes in a number of curved rod - like elastic solids, including carbon nanotubes and biopolymer filaments.
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arxiv:2006.13383
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we report on the discovery of a substellar companion or a massive jupiter orbiting the g5v star hd16760 with the spectrograph sophie installed on the ohp 1. 93 - m telescope. characteristics and performances of the spectrograph are presented, as well as the sophie exoplanet consortium program. with a minimum mass of 14. 3 mjup, an orbital period of 465 days and an eccentricity of 0. 067, hd16760b seems to be located just at the end of the mass distribution of giant planets, close to planet / brown - dwarf transition. its quite circular orbit supports a formation in a gaseous protoplanetary disk.
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arxiv:0907.3559
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between the launch of the \ textit { ggs wind } spacecraft in 1994 november and the end of 2010, the konus - \ textit { wind } experiment detected 296 short - duration gamma - ray bursts ( including 23 bursts which can be classified as short bursts with extended emission ). during this period, the ipn consisted of up to eleven spacecraft, and using triangulation, the localizations of 271 bursts were obtained. we present the most comprehensive ipn localization data on these events. the short burst detection rate, $ \ sim $ 18 per year, exceeds that of many individual experiments.
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arxiv:1301.3740
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superconductors hosting long - sought excitations called majorana fermions may be ultimately used as qubits of fault - tolerant topological quantum computers. a crucial challenge toward the topological quantum computer is to implement quantum operation of nearly degenerate quantum states as a dynamical process of majorana fermions. in this paper, we investigate the braiding dynamics of majorana fermions on superconducting nanowires. in a finite size system, a non - adiabatic dynamical process dominates the non - abelian braiding that operates qubits of majorana fermions. our simulations clarify how qubits behave in the real - time braiding process, and elucidate the optimum condition of superconducting nanowires for efficient topological quantum operation.
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arxiv:1405.5153
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we present detailed energy dispersions near the fermi level on the monolayer perovskite ruthenate sr2ruo4, determined by high - resolution angle - resolved photoemission spectroscopy. an orbital selectivity of the kink in the dispersion of sr2ruo4 has been found : a kink for the ru 4d _ xy orbital is clearly observed, but not for the ru 4d _ yz and 4d _ zx ones. the result provides insight into the origin of the kink.
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arxiv:cond-mat/0508312
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the columbia scientific ballooning facility operates stratospheric balloon flights out of mcmurdo station in antarctica. we use balloon trajectory data from 40 flights between 1991 and 2016 to give the first quantification of trajectory statistics. we provide the probabilities as a function of time for the payload to be between given latitudes, and we quantify the southernmost and northernmost latitudes a payload is likely to attain. we find that for the median flight duration of 19 days, there is 90 % probability the balloon would drift as far south as $ 88 ^ { \ circ } $ s or as far north as $ 71 ^ { \ circ } $ s ; shorter flights are likely to experience smaller ranges in latitude. these statistics, which are available digitally in the public domain, will enable scientists planning future balloon flights make informed decisions during both mission design and execution.
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arxiv:2105.04173
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a novel generalization of the prouhet - thue - morse sequence to binary $ \ pm 1 $ - weight sequences is presented. derived from rademacher functions, these weight sequences are shown to satisfy interesting orthogonality and recurrence relations. in addition, a result useful in describing these weight sequences as sidelobes of doppler tolerant waveforms in radar is established.
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arxiv:1405.6958
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we obtain a class of dyonic black string solutions in 6d salam - sezgin model. we then calculate various thermodynamic quantities associated with this solution. interestingly, for the thermodynamic quantities to be well defined, the temperature is bounded from above. however, the mass and entropy can still grow without any upper bound, reaching infinity at the maximal temperature. the quantization condition obeyed by various charges is also analyzed. in particular, we find that the dirac quantization condition selects one particular sign choice for the magnetic string charges.
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arxiv:2310.16899
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a unified thermodynamic algorithm ( uta ) is presented for constructing thermodynamically consistent dynamical systems, i. e., systems that have hamiltonian and dissipative parts that conserve energy while producing entropy. the algorithm is based on the metriplectic 4 - bracket given in morrison and updike [ phys. \ rev. \ e 109, 045202 ( 2024 ) ]. a feature of the uta is the force - flux relation $ \ mathbf { j } ^ \ alpha = - l ^ { \ alpha \ beta } \, \ nabla ( \ delta h / \ delta \ xi ^ \ beta ) $ for phenomenological coefficients $ l ^ { \ alpha \ beta } $, hamiltonian $ h $ and dynamical variables $ \ xi ^ \ beta $. the algorithm is applied to the navier - stokes - fourier, the cahn - hilliard - navier - stokes, and and brenner - navier - stokes - fourier systems, and significant generalizations of these systems are obtained.
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arxiv:2501.00159
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we prove anderson localization for the discrete laplace operator on radial tree graphs with random branching numbers. our method relies on the representation of the laplace operator as the direct sum of half - line jacobi matrices whose entries are non - degenerate, independent, identically distributed random variables with singular distributions.
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arxiv:1803.06037
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we selected all radio - quiet agn in the latest release of sloan digital sky survey quasar catalog, with redshift in the range 0. 56 - 0. 73. about 4000 ( ~ 80 % ) of these have been detected in all four ir - bands of wise ( wide - field infrared survey explorer ). this is the largest sample suitable to study the disc - torus connection. we find that the torus reprocesses on average ~ 1 / 3 - 1 / 2 of the accretion disc luminosity.
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arxiv:1204.2556
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the phase boundaries for corner wetting ( filling ) in square and diagonal lattice ising models are exactly determined and show a universal shift relative to wetting near the bulk criticality. more generally, scaling theory predicts that the filling phase boundary shift for wedges and cones is determined by a universal scaling function $ r _ d ( \ psi ) $ depending only on the opening angle $ 2 \ psi $. $ r _ d ( \ psi ) $ is determined exactly in $ d = 2 $ and approximately in higher dimensions using non - classical local functional and mean - field theory. detailed numerical transfer matrix studies of the the magnetisation profile in finite - size ising squares support the conjectured connection between filling and the strong - fluctuation regime of wetting.
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arxiv:cond-mat/0110653
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over the last half century the liquid - gas phase transition and the magnetization phase transition have come to be well understood. after an order parameter, $ r $, is defined, it can be derived how $ r = 0 $ for $ t > t _ c $ and how $ r \ propto ( t _ c - t ) ^ \ gamma $ at lowest order for $ t < t _ c $. the value of $ \ gamma $ appears to not depend on physical details of the system, but very much on dimensionality. no phase transitions exist for one - dimensional systems. for systems of four or more dimensions, each unit is interacting with sufficiently many neighbors to warrant a mean - field approach. the mean - field approximation leads to $ \ gamma = 1 / 2 $. in this article we formulate a realistic system of coupled oscillators. each oscillator moves forward through a cyclic 1d array of $ n $ states and the rate at which an oscillator proceeds from state $ i $ to state $ i + 1 $ depends on the populations in states $ i + 1 $ and $ i - 1 $. we study how the phase transitions occur from a homogeneous distribution over the states to a clustered distribution. a clustered distribution means that oscillators have synchronized. we define an order parameter and we find that the critical exponent takes on the mean - field value of 1 / 2 for any $ n $. however, as the number of states increases, the phase transition occurs for ever smaller values of $ t _ c $. we present rigorous mathematics and simple approximations to develop an understanding of the phase transitions in this system. we explain why and how the critical exponent value of 1 / 2 is expected to be robust and we discuss a wet - lab experimental setup to substantiate our findings.
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arxiv:2003.02624
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dynamic programming ( dp ) is a fundamental and powerful algorithmic paradigm taught in most undergraduate ( and many graduate ) algorithms classes. dp problems are challenging for many computer science students because they require identifying unique problem structures and a refined understanding of recursion. in this paper, we present dpvis, a python library that helps students understand dp through a frame - by - frame animation of dynamic programs. dpvis can easily generate animations of dynamic programs with as little as two lines of modifications compared to a standard python implementation. for each frame, dpvis highlight the cells that have been read from and written to during an iteration. moreover, dpvis allows users to test their understanding by prompting them with questions about the next operation performed by the algorithm. we deployed dpvis as a learning tool in an undergraduate algorithms class, and report on the results of a survey. the survey results suggest that dpvis is especially helpful for visualizing the recursive structure of dp. although some students struggled with the installation of the tool ( which has been simplified since the reported deployment ), essentially all other students found the tool to be useful for understanding dynamic programs. dpvis is available at https : / / github. com / itsdawei / dpvis.
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arxiv:2411.07705
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superconductivity was achieved in ti - doped iron - arsenide compound sr4cr0. 8ti1. 2o6fe2as2 ( abbreviated as cr - feas - 42622 ). the x - ray diffraction measurement shows that this material has a layered structure with the space group of \ emph { p4 / nmm }, and with the lattice constants a = b = 3. 9003 a and c = 15. 8376 a. clear diamagnetic signals in ac susceptibility data and zero - resistance in resistivity data were detected at about 6 k, confirming the occurrence of bulk superconductivity. meanwhile we observed a superconducting transition in the resistive data with the onset transition temperature at 29. 2 k, which may be induced by the nonuniform distribution of the cr / ti content in the feas - 42622 phase, or due to some other minority phase.
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arxiv:0904.0972
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experiments with shadowgraph visualization reveal a subcritical transition to a hexagonal convection pattern in thin liquid layers that have a free upper surface and are heated from below. the measured critical marangoni number ( 84 ) and observation of hysteresis ( 3 % ) agree with theory. in some experiments, imperfect bifurcation is observed and is attributed to deterministic forcing caused in part by the lateral boundaries in the experiment.
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arxiv:patt-sol/9507002
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in this study, we develop a methodology for model reduction and selection informed by global sensitivity analysis ( gsa ) methods. we apply these techniques to a control model that takes systolic blood pressure and thoracic tissue pressure data as inputs and predicts heart rate in response to the valsalva maneuver ( vm ). the study compares four gsa methods based on sobol ' indices ( sis ) quantifying the parameter influence on the difference between the model output and the heart rate data. the gsa methods include standard scalar sis determining the average parameter influence over the time interval studied and three time - varying methods analyzing how parameter influence changes over time. the time - varying methods include a new technique, termed limited - memory sis, predicting parameter influence using a moving window approach. using the limited - memory sis, we perform model reduction and selection to analyze the necessity of modeling both the aortic and carotid baroreceptor regions in response to the vm. we compare the original model to three systematically reduced models including ( i ) the aortic and carotid regions, ( ii ) the aortic region only, and ( iii ) the carotid region only. model selection is done quantitatively using the akaike and bayesian information criteria and qualitatively by comparing the neurological predictions. results show that it is necessary to incorporate both the aortic and carotid regions to model the vm.
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arxiv:2005.12879
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while neural network models are making significant progress in piano transcription, they are becoming more resource - consuming due to requiring larger model size and more computing power. in this paper, we attempt to apply more prior about piano to reduce model size and improve the transcription performance. the sound of a piano note contains various overtones, and the pitch of a key does not change over time. to make full use of such latent information, we propose hppnet that using the harmonic dilated convolution to capture the harmonic structures and the frequency grouped recurrent neural network to model the pitch - invariance over time. experimental results on the maestro dataset show that our piano transcription system achieves state - of - the - art performance both in frame and note scores ( frame f1 93. 15 %, note f1 97. 18 % ). moreover, the model size is much smaller than the previous state - of - the - art deep learning models.
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arxiv:2208.14339
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dispersion of $ 1100 \ pm500 $ km s $ ^ { - 1 } $.
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arxiv:2501.11879
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in this work we study relations between regularity of invariant foliations and lyapunov exponents of partially hyperbolic diffeomorphisms. we suggest a new regularity condition for foliations in terms of desintegration of lebesgue measure which can be considered as a criterium for rigidity of lyapunov exponents.
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arxiv:1203.0142
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occurs when another transcription factor called a repressor binds to a dna sequence called an operator, which is part of an operon, to prevent transcription. repressors can be inhibited by compounds called inducers ( e. g., allolactose ), thereby allowing transcription to occur. specific genes that can be activated by inducers are called inducible genes, in contrast to constitutive genes that are almost constantly active. in contrast to both, structural genes encode proteins that are not involved in gene regulation. in addition to regulatory events involving the promoter, gene expression can also be regulated by epigenetic changes to chromatin, which is a complex of dna and protein found in eukaryotic cells. = = = genes, development, and evolution = = = development is the process by which a multicellular organism ( plant or animal ) goes through a series of changes, starting from a single cell, and taking on various forms that are characteristic of its life cycle. there are four key processes that underlie development : determination, differentiation, morphogenesis, and growth. determination sets the developmental fate of a cell, which becomes more restrictive during development. differentiation is the process by which specialized cells arise from less specialized cells such as stem cells. stem cells are undifferentiated or partially differentiated cells that can differentiate into various types of cells and proliferate indefinitely to produce more of the same stem cell. cellular differentiation dramatically changes a cell ' s size, shape, membrane potential, metabolic activity, and responsiveness to signals, which are largely due to highly controlled modifications in gene expression and epigenetics. with a few exceptions, cellular differentiation almost never involves a change in the dna sequence itself. thus, different cells can have very different physical characteristics despite having the same genome. morphogenesis, or the development of body form, is the result of spatial differences in gene expression. a small fraction of the genes in an organism ' s genome called the developmental - genetic toolkit control the development of that organism. these toolkit genes are highly conserved among phyla, meaning that they are ancient and very similar in widely separated groups of animals. differences in deployment of toolkit genes affect the body plan and the number, identity, and pattern of body parts. among the most important toolkit genes are the hox genes. hox genes determine where repeating parts, such as the many vertebrae of snakes, will grow in a developing embryo or larva. = = evolution = = = = = evolutionary
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https://en.wikipedia.org/wiki/Biology
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developed navier - stokes turbulence is simulated with varying wavevector mode reductions. the flatness and the skewness of the velocity derivative depend on the degree of mode reduction. they show a crossover towards the value of the full numerical simulation when the viscous subrange starts to be resolved. the intermittency corrections of the scaling exponents of the pth order velocity structure functions seem to depend mainly on the proper resolution of the inertial subrange. universal scaling properties ( i. e., independent of the degree of mode reduction ) are found for the relative scaling exponents rho which were recently defined by benzi et al.
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arxiv:chao-dyn/9608004
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in this paper, we explore the interplay between topological structures and phase retrieval in the context of projective hilbert spaces. this work provides not only a deeper understanding and a new classification of the phase retrieval property in hilbert spaces but also a way for further investigations into the topological underpinnings of quantum states.
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arxiv:2408.05317
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we study the three - dimensional magnetic structure of solar active region 11158, which produced one x - class and several m - class flares on 2011 february 13 $ - $ 16. we focus on the magnetic twist in four flare events, m6. 6, x2. 2, m1. 0, and m1. 1. the magnetic twist is estimated from the nonlinear force - free field extrapolated from the vector fields obtained from the helioseismic and magnetic imager on board the solar dynamic observatory using magnetohydrodynamic relaxation method developed by \ cite { 2011apj... 738.. 161i }. we found that strongly twisted lines ranging from half - turn to one - turn twist were built up just before the m6. 6 - and x2. 2 flares and disappeared after that. because most of the twist remaining after these flares was less than half - turn twist, this result suggests that the buildup of magnetic twist over the half - turn twist is a key process in the production of large flares. on the other hand, even though these strong twists were also built up just before the m1. 0 and m1. 1 flares, most of them remained afterwords. careful topological analysis before the m1. 0 and m1. 1 flares shows that the strongly twisted lines were surrounded mostly by the weakly twisted lines formed in accordance with the clockwise motion of the positive sunspot, whose footpoints are rooted in strong magnetic flux regions. these results imply that these weakly twisted lines might suppress the activity of the strongly twisted lines in the last two m - class flares.
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arxiv:1304.8073
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context. the fraction of field binaries on retrograde orbits about the milky way is significantly lower compared to its prograde counterpart. chemical and dynamical evidence suggests that the retrograde stellar population originates from $ \ omega $ centauri, which is either the most massive globular cluster ( gc ) of the milky way or the putative core of a former dwarf galaxy. aims. star formation conditions required to produce the retrograde binary population are constrained assuming that the retrograde stellar population originates from $ \ omega $ centauri ' s progenitor. methods. we match the observed low binary fraction with dynamical population synthesis models, including a universal initial binary population and dynamical processing in star clusters, making use of the publicly available binary population synthesis tool bipos1. results. it is found that either the gc progenitor of $ \ omega $ centauri must have formed with a stellar density of $ \ approx 10 ^ 8 \ ; m _ { sun } \ ; pc ^ { - 3 } $ or the $ \ omega $ centauri dwarf galaxy ' s progenitor star cluster population must have formed in an extreme starburst with a star formation rate exceeding $ 1000 \ ; m _ { sun } \ ; yr ^ { - 1 } $ and probably a top - heavy embedded - cluster mass function with suppressed low - mass cluster formation. the separation and mass ratio distribution for retrograde field binaries are predicted for comparison with future observations. conclusions. a viable solution for the deficiency of binaries on retrograde orbits is presented, and star formation conditions for $ \ omega $ centauri as well as orbital parameter distributions for the milky way ' s retrograde binary population are predicted. the dwarf galaxy origin for $ \ omega $ centauri is tentatively preferred within the present context.
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arxiv:2112.00753
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we study the axial - vector and the induced pseudoscalar form factors associated with the weak transitions between the octet baryon members in nuclear medium, using a covariant constituent quark model. we extend previous calculations of the axial transition form factors from the vacuum ( free space ) to the nuclear medium ( symmetric nuclear matter ). the extension of the model to the nuclear medium takes into account the modifications of the properties of hadrons in the medium ( masses and coupling constants ), as determined by the quark - meson coupling model. the axial - vector ( $ g _ a $ ) and the induced pseudoscalar ( $ g _ p $ ) form factors are evaluated for different values of the nuclear density $ \ rho $ in terms of the square transfer momentum $ q ^ 2 = - q ^ 2 $. we conclude that, in general, the $ g _ a $ and $ g _ p $ form factors are reduced in the nuclear medium. the reduction is stronger for light baryons and high densities. the medium modifications are milder for the heavier octet baryons, particularly at large $ q ^ 2 $. the calculations presented here can be used to estimate the cross sections of neutrino and antineutrino scattering with nucleus, and neutrino and antineutrino scattering with hyperons bound to a nucleus, as well as those in the cores of compact stars.
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arxiv:2406.07958
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we investigate the energy structures and the dynamics of a bose - einstein condensates ( bec ) in a triple - well potential coupled a high finesse optical cavity within a mean field approach. due to the intrinsic atom - cavity field nonlinearity, several interesting phenomena arise which are the focuses of this work. for the energy structure, the bistability appears in the energy levels due to this atoms - cavity field nonlinearity, and the same phenomena can be found in the intra - cavity photons number. with an increase of the pump - cavity detunings, the higher and lower energy levels show a loop structure due to this cavity - mediated effects. in the dynamical process, an extensive numerical simulation of localization of the becs for atoms initially trapped in one -, two -, and three - wells are performed for the symmetric and asymmetric cases in detail. it is shown that the the transition from oscillation to the localization can be modified by the cavity - mediated potential, which will enlarge the regions of oscillation. with the increasing of the atomic interaction, the oscillation is blocked and the localization emerges. the condensates atoms can be trapped either in one -, two -, or in three wells eventually where they are initially uploaded for certain parameters. in particular, we find that the transition from the oscillation to the localization is accompanied with some irregular regime where tunneling dynamics is dominated by chaos for this cavity - mediated system.
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arxiv:1207.2905
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save for some special cases, current training methods for generative adversarial networks ( gans ) are at best guaranteed to converge to a ` local nash equilibrium ` ( lne ). such lnes, however, can be arbitrarily far from an actual nash equilibrium ( ne ), which implies that there are no guarantees on the quality of the found generator or classifier. this paper proposes to model gans explicitly as finite games in mixed strategies, thereby ensuring that every lne is an ne. with this formulation, we propose a solution method that is proven to monotonically converge to a resource - bounded nash equilibrium ( rb - ne ) : by increasing computational resources we can find better solutions. we empirically demonstrate that our method is less prone to typical gan problems such as mode collapse, and produces solutions that are less exploitable than those produced by gans and mgans, and closely resemble theoretical predictions about nes.
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arxiv:1806.07268
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we study $ { \ cal n } = 3 $ linear chern - simons - matter theories in the planar limit. the matter content of the theory is depicted by a linear - shape diagram with $ n $ nodes and $ n - 1 $ links for any $ n $. the free energy and the vevs of bps wilson loops are given in terms of a single 1 - form on $ \ mathbb { cp } ^ 1 $ which can be determined explicitly for all linear theories. the analytic structure of the vevs of the wilson loops is investigated in detail for $ n = 1 $ and $ n = 2 $. the addition of fundamental matters is also discussed.
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arxiv:1904.11728
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preconcentration of the target compound is a critical step that ensures the accuracy of the subsequent chemical analysis. in this work, we present a straightforward yet effective liquid - liquid extraction approach based on surface nanodroplets ( i. e., nanoextraction ) for offline analysis of highly diluted sample solutions. the extraction and sample collection were streamlined in a 3 - m microcapillary tube. the concentration of the target analyte in surface nanodroplets was significantly increased compared to the concentration in the sample solution, reaching several orders of magnitudes. a limit of detection ( lod ) was decreased by a factor of $ \ sim 10 ^ 3 $ for an organic model compound in fourier - transform infrared spectroscopy ( ftir ) measurements and $ \ sim 10 ^ 5 $ for a model fluorescent dye in fluorescence detection. the quantitative analysis of the organic compound was also achieved in a wide concentration region from $ 10 ^ { - 3 } $ m to $ 10 ^ { - 4 } $ m. the total volume of surface nanodroplets can be manipulated to further enhance extraction efficiency, according to the principle that governs droplet formation by solvent exchange. additionally, our method exhibited significantly improved sensitivity compared to traditional dispersive liquid - liquid microextraction ( dllme ). the lod of the fluorescent dye and the organic model compound obtained with dllme was 3 orders of magnitude and 20 times higher than the lod achieved through nanoextraction approach. the nanoextraction developed in this work can be applied to preconcentrate multi - compounds from river water samples, without clear interference from each other. this can further extend its applicability for the detection and quantification of target analytes in complex aqueous samples by common analytical instruments.
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arxiv:2306.14860
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we present halpha rotation curves for a sample of 15 dwarf and lsb galaxies. from these, we derive limits on the slopes of the central mass distributions. assuming the density distributions of dark matter halos follow a power - law at small radii, rho ( r ) ~ r ^ ( - alpha ), we find inner slopes in the range 0 < alpha < 1 for most galaxies. in general, halos with constant density cores ( \ alpha = 0 ) provide somewhat better fits, but the majority of our galaxies ( ~ 75 % ) are also consistent with alpha = 1, provided that the r - band mass - to - light ratios are smaller than about 2. halos with alpha = 1. 5, however, are ruled out in virtually every case. to investigate the robustness of these results we discuss and model several possible causes of systematic errors including non - circular motions, slit width, seeing, and slit alignment errors. taking the associated uncertainties into account, we conclude that even for the 25 % of the cases where alpha = 1 seems inconsistent with the rotation curves, we cannot rule out cusp slopes this steep. inclusion of literature samples similar to the one presented here leads to the same conclusion when possible systematic errors are taken into account. in the ongoing debate on whether the rotation curves of dwarf and lsb galaxies are consistent with predictions for a cdm universe, we argue that our sample and the literature samples discussed in this paper provide insufficient evidence to rule out halos with alpha = 1. at the same time, we note that none of the galaxies in these samples require halos with steep cusps, as most are equally well or better explained by constant density cores. ( abridged )
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arxiv:astro-ph/0210152
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this paper deals with the notion of quadratic differential in spherical cr geometry ( or more generally on strictly pseudoconvex cr manifolds ). we get to this notion by studying a splitting of rumin complex and discuss its first features such as trajectories and length. we also define several differential operators on quadratic differentials that lead to analogue of half - translation structures on spherical cr manifolds. finally, we work on known examples of quasiconformal maps in the heisenberg group with extremal properties and explicit how quadratic differentials are involved in those. in addition, on our way to quadratic differentials, we define a differential complex on strictly pseudoconvex cr manifolds with a finite dimensional cohomology space. it leads to a new cr invariant that we compute for compact manifolds endowed with a cr action of the circle.
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arxiv:1807.07844
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silicene, as the silicon analog of graphene, has been successfully fabricated by epitaxial growing on various substrates. similar to free - standing graphene, free - standing silicene possesses a honeycomb structure and dirac - cone - shaped energy band, resulting in many fascinating properties such as high carrier mobility, quantum spin hall effect, quantum anomalous hall effect, and quantum valley hall effect. the maintenance of the honeycomb crystal structure and the dirac cone of silicene is crucial for observation of its intrinsic properties. in this review, we systematically discuss the substrate effects on the atomic structure and electronic properties of silicene from a theoretical point of view, especially focusing on the changes of the dirac cone.
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arxiv:1507.02273
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the clustering attachment model introduced in the paper bagrow and brockmann ( 2013 ) may be used as an evolution tool of random networks. we propose a new clustering attachment model which can be considered as the limit of the former clustering attachment model as model parameter $ \ alpha $ tends to zero. we focus on the study of a total triangle count that is considered in the literature as an important characteristic of the network clustering. it is proved that total triangle count tends to infinity a. s. for the proposed model. our simulation study is used for the modeling of sequences of triangle counts. it is based on the interpretation of the clustering attachment as a generalized p \ ' { o } lya - eggenberger urn model that is introduced here at first time.
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arxiv:2401.11548
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we show possibility of the plane couette ( pc ) flow instability for reynolds number re > reth = 140. this new result of the linear hydrodynamic stability theory is obtained on the base of refusal from the traditionally used assumption on longitudinal periodicity of the disturbances along the direction of the fluid flow. we found that earlier existing understanding on the linear stability of this flow for any arbitrary large reynolds number is directly related with an assumption on the separation of the variables of the spatial variability for the disturbance field and their periodicity in linear theory of stability. by the refusal from the pointed assumptions also for the plane poiseuille ( pp ) flow, we get a new threshold reynolds value reth = 1040 that with 4 % accuracy agrees with the experiment contrary to more than 500 % discrepancy for the earlier known estimate reth = 5772 obtained in the frame of the linear theory but when using the " normal " disturbance form ( s. a. orszag, 1971 ).
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arxiv:1509.08910
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the discovery of galaxies with regularly rotating discs at redshifts $ \ geq $ has been a puzzling challenge to galaxy formation models that tend to predict chaotic gas kinematics in the early universe as a consequence of gas accretion, mergers and efficient feedback. in this work, we investigated the kinematics of five highly resolved galaxies at z $ \ sim $ 4. 5 observed with alma in the [ cii ] 158 $ \ mu $ m emission line. the sample is diverse : aztec1 ( starburst galaxy ), bri1335 - 0417 ( starburst and quasar host galaxy ), j081740 ( normal star - forming galaxy ) and sgp38326 ( two starburst galaxies in a group ). the five galaxies show velocity gradients, but four were found to be rotating discs while the remaining, aztec1, is likely a merger. we studied the gas kinematics of the discs using 3dbarolo and found that they rotate with maximum rotation velocities between 198 and 562 km / s while the gas velocity dispersions, averaged across the discs, are between 49 and 75 km / s. the rotation curves are generally flat and the galaxies have ratios of ordered - to - random motion ( v / $ \ sigma $ ) between 2. 7 and 9. 8. we present cannubi, an algorithm for fitting the disc geometry of rotating discs in 3d emission - line observations prior to modelling the kinematics, with which we find indications that these discs may have thicknesses of the order of 1 kpc. this study shows that early disc formation with a clear dominance of rotation with respect to turbulent motions is present across a variety of galaxy types.
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arxiv:2302.03049
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spin waves are perturbations in the relative orientation of magnetic moments in a continuous magnetic system, which have been proposed as a new kind of information carrier for spin - based low power applications. for this purpose, a major obstacle to overcome is the energy - efficient excitation of coherent short wavelength spin waves and alternatives to excitation via the oersted field of an alternating current need to be explored. here we show, by means of micromagnetic simulations, how, in a perpendicularly magnetized thin strip, a domain wall pinned at a geometrical constriction emits spin waves when forced to rotate by the application of a low direct current flowing along the strip. spin waves propagate only in the direction of the electron ' s flow at the first odd harmonic of the domain wall rotation frequency for which propagation is allowed. excitation is due to in - plane dipolar stray field of the rotating domain wall and that the resulting unidirectionality is a consequence of the domain wall displacement at the constriction. on the other hand, the application of an external field opposing domain wall depinning breaks the symmetry for spin wave propagation in the two domains, allowing emission in both directions but at different frequencies. the results presented define a new approach to produce tunable high frequency spin wave emitters of easy fabrication and low power consumption.
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arxiv:1706.05873
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the partition function $ p ( n ) $ has been a testing ground for applications of analytic number theory to combinatorics. in particular, hardy and ramanujan invented the " circle method " to estimate the size of $ p ( n ) $, which was later perfected by rademacher who obtained an exact formula. recently, chan and wang considered the fractional partition functions, defined by $ \ sum _ { n = 0 } ^ \ infty p _ { \ alpha } ( n ) x ^ n : = \ prod _ { k = 1 } ^ \ infty ( 1 - x ^ k ) ^ { - \ alpha } $. in this paper we use the rademacher circle method to find an exact formula for $ p _ \ alpha ( n ) $ and study its implications, including log - concavity and the higher - order generalizations ( i. e., the tur \ ' an inequalities ) that $ p _ \ alpha ( n ) $ satisfies.
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arxiv:1907.03026
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we have developed the mean - field theory of coexisting charge - density waves ( cdw ) and unconventional charge - density waves ( ucdw ). the double phase transition manifests itself in the thermodynamic quantities and in the magnetic response, such as spin susceptibility and spin - lattice relaxation rate. our theory applies to quasi - one dimensional ( tase _ 4 ) _ 2i, where above the cdw transition, thermal fluctuations die out rapidly, but robust pseudogap behaviour is still detected. we argue, that the fluctuations are suppressed due to ucdw, which partially gaps the fermi surface, and causes non - fermi - liquid ( pseudogap ) behaviour.
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arxiv:cond-mat/0511576
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jet cross sections have been measured for the first time in proton - proton collisions at a centre - of - mass energy of 7 tev using the atlas detector. the measurement uses an integrated luminosity of 17 nb - 1 recorded at the large hadron collider. the anti - kt algorithm is used to identify jets, with two jet resolution parameters, r = 0. 4 and 0. 6. the dominant uncertainty comes from the jet energy scale, which is determined to within 7 % for central jets above 60 gev transverse momentum. inclusive single - jet differential cross sections are presented as functions of jet transverse momentum and rapidity. dijet cross sections are presented as functions of dijet mass and the angular variable $ \ chi $. the results are compared to expectations based on next - to - leading - order qcd, which agree with the data, providing a validation of the theory in a new kinematic regime.
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arxiv:1009.5908
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the most general situation of the reinforcement of a plate with multiple holes by several patches is considered. there is no restriction on the number and the location of the patches. two types of the patch attachment are considered : only along the boundary of the patch or both along the boundary of the patch and the boundaries of the holes which this patch covers. the unattached boundaries of the holes may be loaded with given in - plane stresses. the mechanical problem is reduced to the system of singular integral equations which can be further reduced to the system of fredholm equations. a new numerical procedure for the solution of the system of singular integral equations is proposed in this paper. it can be observed that this procedure provides a noticeable improvement from the one presented in zemlyanova \ cite { zem2007 }, zemlyanova and silvestrov \ cite { zemsil2007 }, \ cite { zemsil2009 } and allows to achieve a significantly better numerical convergence with less computational effort.
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arxiv:1201.6666
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high - pressure induced structural transition from zircon - type phase into scheelite - type phase in yvo $ _ 4 $ is studied using ab initio calculations. several structures with compressed volumes are evaluated, where for every considered volume the c / a ratio and atomic positions are optimised. the transition pressure and transition volume change are calculated. the reports on yvo $ _ 4 $ electronic structure and electronic band gap behaviour are followed by results of x - ray photoemission spectra xps calculations. most of our theoretical predictions are compared with experimental results taken from literature.
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arxiv:2503.15051
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a generalization of the two - dimensional yang - mills and generalized yang - mills theory is introduced in which the building b - f theory is nonlocal in the auxiliary field. the classical and quantum properties of this nonlocal generalization are investigated and it is shown that for large gauge groups, there exist a simple correspondence between the properties a nonlocal theory and its corresponding local theory.
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arxiv:hep-th/0101005
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a single quantum emitter can possess a very strong intrinsic nonlinearity, but its overall promise for nonlinear effects is hampered by the challenge of efficient coupling to incident photons. common nonlinear optical materials, on the other hand, are easy to couple to but are bulky, imposing a severe limitation on the miniaturization of photonic systems. in this work, we show that a single organic molecule acts as an extremely efficient nonlinear optical element in the strong coupling regime of cavity quantum electrodynamics. we report on single - photon sensitivity in nonlinear signal generation and all - optical switching. our work promotes the use of molecules for applications such as integrated photonic circuits, operating at very low powers.
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arxiv:2105.02560
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wireless sensor networks ( wsns ) have many potential applications [ 1, 5 ] and unique challenges. they usually consist of hundreds or thousands small sensor nodes such as mica2, which operate autonomously ; conditions such as cost, invisible deployment and many application domains, lead to small size and limited resources sensors [ 2 ]. wsns are susceptible to many types of link layer attacks [ 1 ] and most of traditional networks security techniques are unusable on wsns [ 2 ] ; due to wireless and shared nature of communication channel, untrusted transmissions, deployment in open environments, unattended nature and limited resources [ 1 ]. so, security is a vital requirement for these networks ; but we have to design a proper security mechanism that attends to wsn ' s constraints and requirements. in this paper, we focus on security of wsns, divide it ( the wsns security ) into four categories and will consider them, include : an overview of wsns, security in wsns, the threat model on wsns, a wide variety of wsns ' link layer attacks and a comparison of them. this work enables us to identify the purpose and capabilities of the attackers ; also, the goal and effects of the link layer attacks on wsns are introduced. also, this paper discusses known approaches of security detection and defensive mechanisms against the link layer attacks ; this would enable it security managers to manage the link layer attacks of wsns more effectively.
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arxiv:1103.5589
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we present a ` ` toy ' ' model for breaking supersymmetric gauge theories at the effective lagrangian level. we show that it is possible to achieve the decoupling of gluinos and squarks, below a given supersymmetry breaking scale m, in the fundamental theory for super qcd once a suitable choice of supersymmetry breaking terms is made. a key feature of the model is the description of the ordinary qcd degrees of freedom via the auxiliary fields of the supersymmetric effective lagrangian. once the anomaly induced effective qcd meson potential is deduced we also suggest a decoupling procedure, when a flavored quark becomes massive, which mimics the one employed by seiberg for supersymmetric theories. it is seen that, after quark decoupling, the qcd potential naturally converts to the one with one less flavor. finally we investigate the n _ c and n _ f dependence of the \ eta ^ { \ prime } mass.
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arxiv:hep-th/9806229
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by subjecting a dynamical system to a series of short pulses and varying several time delays we can obtain multidimensional characteristic measures of the system. multidimensional kullback - leibler response function ( klrf ), which are based on the kullback - leibler distance between the initial and final states, are defined. we compare the klrf, which are nonlinear in the probability density, with ordinary response functions ( orf ) obtained from the expectation value of a dynamical variable, which are linear. we show that the klrf encode different level of information regarding the system ' s dynamics. for overdamped stochastic dynamics two dimensional klrf shows a qualitatively different variation with the time delays between pulses, depending on whether the system is initially in a steady state, or in thermal equilibrium.
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arxiv:1003.4297
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the mobile data traffic has been exponentially growing during the last decades, which has been enabled by the densification of the network infrastructure in terms of increased cell density ( i. e., ultra - dense network ( udn ) ) and / or increased number of active antennas per access point ( ap ) ( i. e., massive multiple - input multiple - output ( mmimo ) ). however, neither udn nor mmimo will meet the increasing data rate demands of the sixth generation ( 6g ) wireless communications due to the inter - cell interference and large quality - of - service variations, respectively. cell - free ( cf ) mmimo, which combines the best aspects of udn and mmimo, is viewed as a key solution to this issue. in such systems, each user equipment ( ue ) is served by a preferred set of surrounding aps cooperatively. in this paper, we provide a survey of the state - of - the - art literature on cf mmimo. as a starting point, the significance and the basic properties of cf mmimo are highlighted. we then present the canonical framework, where the essential details ( i. e., transmission procedure and mathematical system model ) are discussed. next, we provide a deep look at the resource allocation and signal processing problems related to cf mmimo and survey the up - to - date schemes and algorithms. after that, we discuss the practical issues when implementing cf mmimo. potential future directions are then pointed out. finally, we conclude this paper with a summary of the key lessons learned in this field. this paper aims to provide a starting point for anyone who wants to conduct research on cf mmimo for future wireless networks.
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arxiv:2104.13667
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we present arguments that at least part of the inner source of pickup ions in the solar wind might be the material released by sungrazing comets. based on a statistical analysis of sungrazing comets detected over almost eight years of lasco operation ( 1996 - - september 09 2004 ) an overwhelming majority of the observed sungrazers belong to the kreutz group of comets, follows tightly clumped orbits and break up at $ \ sim 40 - 4 $ solar radii in a well defined region of space. the material released from these comets could be ( after ionization ) an important portion of the inner source of pickup ions ( puis ), as the local mass flux of the inner source and cometary puis seem comparable. we indicate time intervals during the year when the cometary puis could be observed from a spacecraft on the earth ' s orbit ( from the end of july until the end of the year ) and show three time intervals when they should be observable by ulysses ( from its launch time until the end of 1990, from the end of november 1994 until mid - may 1995 and from february 2001 until the end of july, 2001 ). we argue that the puis from the inner source should include both singly and doubly charged ions and that this cometary hypothesis alleviates some difficulties ( in particular, the issue of hydrogen deficit ) in the interpretation of the inner source as solar wind neutralized on dust grains close to the sun.
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arxiv:astro-ph/0405148
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a spiking neural network ( snn ) is trained with spike timing dependent plasticity ( stdp ), which is a neuro - inspired unsupervised learning method for various machine learning applications. this paper studies the generalizability properties of the stdp learning processes using the hausdorff dimension of the trajectories of the learning algorithm. the paper analyzes the effects of stdp learning models and associated hyper - parameters on the generalizability properties of an snn. the analysis is used to develop a bayesian optimization approach to optimize the hyper - parameters for an stdp model for improving the generalizability properties of an snn.
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arxiv:2105.14677
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in the recent era, reversible computing is a growing field having applications in nanotechnology, optical information processing, quantum networks etc. in this paper, the authors show the design of a cost effective reversible programmable logic array using vhdl. it is simulated on xilinx ise 8. 2i and results are shown. the proposed reversible programming logic array called rpla is designed by mux gate [ 10 ] & feynman gate for 3 - inputs, which is able to perform any reversible 3 - input logic function or boolean function. furthermore the quantized analysis with camparitive finding is shown for the realized rpla against the existing one. the result shows improvement in the quantum cost and total logical caculation in proposed rpla.
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arxiv:1204.5525
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the interplay of strong and weak decay amplitudes for b - > pion - pion - kaon and b - > kaon - antikaon - kaon, with the pion - pion and kaon - antikaon pairs interacting in isospin - 0 s - wave, is analyzed for pion - pion effective mass from threshold to 1. 2 gev. to improve agreement with experiment of a factorization approach with some qcd corrections, addition of long - distance contributions, called charming penguins is necessary.
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arxiv:hep-ph/0511044
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we study the asymptotic decay of the friedel density oscillations induced by an open boundary in a one - dimensional chain of lattice fermions with a short - range two - particle interaction. from tomonaga - luttinger liquid theory it is known that the decay follows a power law, with an interaction dependent exponent, which, for repulsive interactions, is larger than the noninteracting value $ - 1 $. we first investigate if this behavior can be captured by many - body perturbation theory for either the green function or the self - energy in lowest order in the two - particle interaction. the analytic results of the former show a logarithmic divergence indicative of the power law. one might hope that the resummation of higher order terms inherent to the dyson equation then leads to a power law in the perturbation theory for the self - energy. however, the numerical results do not support this. next we use density functional theory within the local - density approximation and an exchange - correlation functional derived from the exact bethe ansatz solution of the translational invariant model. while the numerical results are consistent with power - law scaling if systems of $ 10 ^ 4 $ or more lattice sites are considered, the extracted exponent is very close to the noninteracting value even for sizeable interactions.
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arxiv:1906.07066
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we provide experimental and theoretical evidence for the realization of the peierls - type structurally distorted state in the quasi - one - dimensional superconductor sc $ _ 3 $ coc $ _ 4 $ by a phonon - softening mechanism. the transition from the high - to the final low - temperature phase below 80k proceeds via an extended intermediate temperature regime between 80k and 150k characterized by phonon - driven atom displacements. in support of the low - dimensional character of the title compound we find a highly anisotropic correlation - length of these dynamic distortions.
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arxiv:2009.03833
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we address the problem of including coulomb distortion effects in inclusive quasielastic ( e, e ' ) reactions using the eikonal approximation. our results indicate that coulomb corrections may become large for heavy nuclei for certain kinematical regions. the issues of our model are presented in detail and the results are compared to calculations of the ohio group, where dirac wave functions were used both for electrons and nucleons. our results are in good agreement with those obtained by exact calculations.
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arxiv:nucl-th/0403047
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we construct, for the first time, various types of specific non - special finite $ p $ - groups having abelian automorphism group. more specifically, we construct groups $ g $ with abelian automorphism group such that $ \ gamma _ 2 ( g ) < \ mathrm { z } ( g ) < \ phi ( g ) $, where $ \ gamma _ 2 ( g ) $, $ \ mathrm { z } ( g ) $ and $ \ phi ( g ) $ denote the commutator subgroup, the center and the frattini subgroup of $ g $ respectively. for a finite $ p $ - group $ g $ with elementary abelian automorphism group, we show that at least one of the following two conditions holds true : ( i ) $ \ mathrm { z } ( g ) = \ phi ( g ) $ is elementary abelian ; ( ii ) $ \ gamma _ 2 ( g ) = \ phi ( g ) $ is elementary abelian, where $ p $ is an odd prime. we construct examples to show the existence of groups $ g $ with elementary abelian automorphism group for which exactly one of the above two conditions holds true.
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arxiv:1304.1974
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this is the technical report of the 9th place in the final result of parse2022 challenge. we solve the segmentation problem of the pulmonary artery by using a two - stage method based on a 3d cnn network. the coarse model is used to locate the roi, and the fine model is used to refine the segmentation result. in addition, in order to improve the segmentation performance, we adopt multi - view and multi - window level method, at the same time we employ a fine - tune strategy to mitigate the impact of inconsistent labeling.
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arxiv:2209.03918
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in this work we present the study of light - front field theories in the realm of axiomatic theory. it is known that when one uses the light - cone gauge pathological poles $ ( k ^ { + } ) ^ { - n } $ arises, demanding a prescription to be employed in order to tame these ill - defined poles and to have correct feynman integrals due to the lack of wick rotation in such theories. in order to shed a new light on this long standing problem we present here a discussion based on the use rigorous mathematical machinery of distributions combined with physical concepts, such as causality, to show how to deal with these singular propagators in a general fashion without making use of any prescription. the first step of our development will consist in showing how analytic representation for propagators arises by requiring general physical properties in the framework of wightman ' s formalism. from that we shall determine the equal - time ( anti ) commutation relations in the light - front form for the scalar, fermionic fields and for the dynamical components of the electromagnetic field. in conclusion, we introduce the epstein - glaser causal method in order to have a mathematical rigorous treatment of the free propagators of the theory, allowing us to discuss the general treatment for propagators of the type $ ( k ^ { + } ) ^ { - n } $. moreover, we show that at given conditions our results reproduce known prescriptions in the literature.
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arxiv:1405.1896
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in this paper, we construct an undecidable 3 - variable superintuitionistic propositional calculus, i. e., a finitely axiomatizable extension of the intuitionistic propositional calculus with axioms containing only 3 variables. since there are no 2 - variable superintuitionistic propositional calculi, this is the minimal possible number of variables.
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arxiv:1504.03358
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automatic subphenotyping from electronic health records ( ehrs ) provides numerous opportunities to understand diseases with unique subgroups and enhance personalized medicine for patients. however, existing machine learning algorithms either focus on specific diseases for better interpretability or produce coarse - grained phenotype topics without considering nuanced disease patterns. in this study, we propose a guided topic model, mixehr - nest, to infer sub - phenotype topics from thousands of disease using multi - modal ehr data. specifically, mixehr - nest detects multiple subtopics from each phenotype topic, whose prior is guided by the expert - curated phenotype concepts such as phenotype codes ( phecodes ) or clinical classification software ( ccs ) codes. we evaluated mixehr - nest on two ehr datasets : ( 1 ) the mimic - iii dataset consisting of over 38 thousand patients from intensive care unit ( icu ) from beth israel deaconess medical center ( bidmc ) in boston, usa ; ( 2 ) the healthcare administrative database pophr, comprising 1. 3 million patients from montreal, canada. experimental results demonstrate that mixehr - nest can identify subphenotypes with distinct patterns within each phenotype, which are predictive for disease progression and severity. consequently, mixehr - nest distinguishes between type 1 and type 2 diabetes by inferring subphenotypes using ccs codes, which do not differentiate these two subtype concepts. additionally, mixehr - nest not only improved the prediction accuracy of short - term mortality of icu patients and initial insulin treatment in diabetic patients but also revealed the contributions of subphenotypes. for longitudinal analysis, mixehr - nest identified subphenotypes of distinct age prevalence under the same phenotypes, such as asthma, leukemia, epilepsy, and depression. the mixehr - nest software is available at github : https : / / github. com / li - lab - mcgill / mixehr - nest.
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arxiv:2410.13217
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the algebras of non - relativistic and of classical mechanics are unstable algebraic structures. their deformation towards stable structures leads, respectively, to relativity and to quantum mechanics. likewise, the combined relativistic quantum mechanics algebra is also unstable. its stabilization requires the non - commutativity of the space - time coordinates and the existence of a fundamental length constant. the new relativistic quantum mechanics algebra has important consequences on the geometry of space - time, on quantum stochastic calculus and on the construction of quantum fields. some of these effects are studied in this paper.
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arxiv:math-ph/9907001
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we calculate high - energy massive string scattering amplitudes of compactified open string. we derive infinite linear relations, or stringy symmetries, among soft high - energy string scattering amplitudes of different string states in the gross kinematic regime ( gr ). in addition, we systematically analyze all hard power - law and soft exponential fall - off regimes of high - energy compactified open string scatterings by comparing the scatterings with their 26d noncompactified counterparts. in particular, we discover the existence of a power - law regime at fixed angle and an exponential fall - off regime at small angle for high - energy compactified open string scatterings. the linear relations break down as expected in all power - law regimes. the analysis can be extended to the high - energy scatterings of the compactified closed string, which corrects and extends the previous results in [ 28 ].
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arxiv:0805.3168
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milliken ' s tree theorem is a deep result in combinatorics that generalizes a vast number of other results in the subject, most notably ramsey ' s theorem and its many variants and consequences. motivated by a question of dobrinen, we initiate the study of milliken ' s tree theorem from the point of view of computability theory. our advance here stems from a careful analysis of the halpern - la \ " { u } chli theorem which shows that it can be carried out effectively ( i. e., that it is computably true ). we use this as the basis of a new inductive proof of milliken ' s tree theorem that permits us to gauge its effectivity in turn. the principal outcome of this is a comprehensive classification of the computable content of milliken ' s tree theorem. we apply our analysis also to several well - known applications of milliken ' s tree theorem, namely devlin ' s theorem, a partition theorem for rado graphs, and a generalized version of the so - called tree theorem of chubb, hirst, and mcnicholl. these are all certain kinds of extensions of ramsey ' s theorem for different structures, namely the rational numbers, the rado graph, and perfect binary trees, respectively. we obtain a number of new results about how these principles relate to milliken ' s tree theorem and to each other, in terms of both their computability - theoretic and combinatorial aspects. we identify again the familiar dichotomy between coding the halting problem or not based on the size of instance, but this is more subtle here owing to the more complicated underlying structures, particularly in the case of devlin ' s theorem. we also establish new structural ramsey - theoretic properties of the rado graph theorem and the generalized chubb - hirst - mcnicholl tree theorem using zucker ' s notion of big ramsey structure.
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arxiv:2007.09739
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we study the size estimate problem for the two - phase shallow shell equations in this paper. our aim is to derive bounds on the volume fraction of each phase assuming that the material properties of the two phases are given. the approach in this paper is based on the translation method. one of the key steps is to connect the shallow shell equations to the thin plate equation.
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arxiv:1204.4962
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we prove that the killing rate of certain degree - lowering " recursion operators " on a polynomial algebra over a finite field grows slower than linearly in the degree of the polynomial attacked. we also explain the motivating application : obtaining a lower bound for the krull dimension of a local component of a big mod - p hecke algebra in the genus - zero case. we sketch the application for p = 2 and p = 3 in level one. the case p = 2 was first established in by nicolas and serre in 2012 using different methods.
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arxiv:1707.09846
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to expand the known number of low - redshift galaxies which lie close to bright ( $ v < 17. 2 $ ) qso lines of sight, we have identified 24 galaxies within 11 arcmins of nine qsos which have been observed with the hubble space telescope ( hst ). galaxies are found between redshifts of $ 0. 0114 - 0. 145 $ and lie between $ 39 - 749 $ $ h ^ { - 1 } $ kpc from qso sightlines. knowing the redshifts of these galaxies has already proved important in understanding results from hst programmes designed to search for uv absorption lines from low - redshift galaxies, and will enable future observations to probe the halos of these galaxies in detail.
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arxiv:astro-ph/9608190
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as image tampering becomes ever more sophisticated and commonplace, the need for image forensics algorithms that can accurately and quickly detect forgeries grows. in this paper, we revisit the ideas of image querying and retrieval to provide clues to better localize forgeries. we propose a method to perform large - scale image forensics on the order of one million images using the help of an image search algorithm and database to gather contextual clues as to where tampering may have taken place. in this vein, we introduce five new strongly invariant image comparison methods and test their effectiveness under heavy noise, rotation, and color space changes. lastly, we show the effectiveness of these methods compared to passive image forensics using nimble [ https : / / www. nist. gov / itl / iad / mig / nimble - challenge ], a new, state - of - the - art dataset from the national institute of standards and technology ( nist ).
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arxiv:1705.00604
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we comment on old and new results related to the destruction of a random recursive tree ( rrt ), in which its edges are cut one after the other in a uniform random order. in particular, we study the number of steps needed to isolate or disconnect certain distinguished vertices when the size of the tree tends to infinity. new probabilistic explanations are given in terms of the so - called cut - tree and the tree of component sizes, which both encode different aspects of the destruction process. finally, we establish the connection to bernoulli bond percolation on large rrt ' s and present recent results on the cluster sizes in the supercritical regime.
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arxiv:1406.2238
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the driving force dependence of the surface velocity and the average height of faceted merged steps, the terrace - surface - slope, and the elementary step velocity in the non - equilibrium steady - state are studied using the monte carlo method. the monte carlo study is based on a lattice model, the restricted solid - on - solid model with point - contact type step - - step attraction ( p - rsos model ). the temperature is selected to be in the step - faceting zone where the surface is surrounded by the ( 001 ) terrace and the ( 111 ) faceted step at equilibrium. long time simulations are performed at this temperature to obtain steady - states for the different driving forces that influence the growth / recession of the surface. a wulff figure of the p - rsos model is produced through the anomalous surface tension calculated using the density - matrix renormalization group method. although the p - rsos model is a simplified model, the model shows a wide variety of dynamics in the step - faceting zone. there are four characteristic driving forces, $ \ delta \ mu _ y $, $ \ delta \ mu _ f $, $ \ delta \ mu _ { co } $, and $ \ delta \ mu _ r $. for $ \ delta \ mu _ { co } < | \ delta \ mu | < \ delta \ mu _ r $, the surface grows / recedes with the successive attachment - detachment of steps to / from a macrostep. when $ | \ delta \ mu | $ exceeds $ \ delta \ mu _ r $, the macrostep vanishes and the surface roughens kinetically. classical 2d heterogeneous multi - nucleation was determined to be valid with slight modifications based on the monte carlo results of the step velocity and the change in the surface slope of the " terrace ". the finite size effects were also determined to be distinctive near equilibrium.
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arxiv:1711.05015
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scattering of the cosmic microwave background ( cmb ) in clusters of galaxies polarizes the radiation. we explore several polarization components which have their origin in the kinematic quadrupole moments induced by the motion of the scattering electrons, either directed or random. polarization levels and patterns are determined in a cluster simulated by the hydrodynamical enzo code. we find that polarization signals can be as high as $ \ sim 1 \ mu $ k, a level that may be detectable by upcoming cmb experiments.
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arxiv:astro-ph/0602528
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stylegan is a state - of - art generative adversarial network architecture that generates random 2d high - quality synthetic facial data samples. in this paper, we recap the stylegan architecture and training methodology and present our experiences of retraining it on a number of alternative public datasets. practical issues and challenges arising from the retraining process are discussed. tests and validation results are presented and a comparative analysis of several different re - trained stylegan weightings is provided 1. the role of this tool in building large, scalable datasets of synthetic facial data is also discussed.
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arxiv:2003.10847
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fa mechanoreceptors achieve this high resolution of sensing by sensing vibrations produced by friction and an interaction of the fingerprint texture moving over fine surface texture. = = implementation = = haptic feedback ( often shortened to just haptics ) is controlled vibrations at set frequencies and intervals to provide a sensation representative of an in - game action ; this includes ' bumps ', ' knocks ', and ' tap ' of one ' s hand or fingers. the majority of electronics offering haptic feedback use vibrations, and most use a type of eccentric rotating mass ( erm ) actuator, consisting of an unbalanced weight attached to a motor shaft. as the shaft rotates, the spinning of this irregular mass causes the actuator and the attached device to shake. piezoelectric actuators are also employed to produce vibrations, and offer even more precise motion than lras, with less noise and in a smaller platform, but require higher voltages than do erms and lras. = = = controller rumble = = = one of the most common forms of haptic feedback in video games is controller rumble. in 1976, sega ' s motorbike game moto - cross, also known as fonz, was the first game to use haptic feedback, causing the handlebars to vibrate during a collision with another vehicle. = = = force feedback = = = force feedback devices use motors to manipulate the movement of an item held by the user. a common use is in automobile driving video games and simulators, which turn the steering wheel to simulate forces experienced when cornering a real vehicle. direct - drive wheels, introduced in 2013, are based on servomotors and are the most high - end, for strength and fidelity, type of force feedback racing wheels. in 2007, novint released the falcon, the first consumer 3d touch device with high resolution three - dimensional force feedback. this allowed the haptic simulation of objects, textures, recoil, momentum, and the physical presence of objects in games. = = = air vortex rings = = = air vortex rings are donut - shaped air pockets made up of concentrated gusts of air. focused air vortices can have the force to blow out a candle or disturb papers from a few yards away. both microsoft research ( airwave ) and disney research ( aireal ) have used air vortices to deliver non - contact haptic feedback. = = = ultrasound = = = focused ultrasound beams can be used to create a localized sense of
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https://en.wikipedia.org/wiki/Haptic_technology
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we find the adjoint of the askey - wilson divided difference operator with respect to the inner procuct on l ^ 2 ( - 1, 1, ( 1 - x ^ 2 ) ^ - 1 / 2 dx ) defined as a cauchy principle value and show that the askey - wilson polynomials are solutions of a q - sturm - liouville problem. from these facts we deduce various properties of the polynomials in a simple and straightforward way. we also provide an operator theoretic description of the askey - wilson operator.
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arxiv:math/9408209
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consider a linear operator equation $ x - kx = f $, where $ f $ is given and $ k $ is a fredholm integral operator with a green ' s function type kernel defined on $ c [ 0, 1 ] $. for $ r \ geq 0 $, we employ the interpolatory projection at $ 2r + 1 $ collocation points ( not necessarily gauss points ) onto a space of piecewise polynomials of degree $ \ leq 2r $ with respect to a uniform partition of $ [ 0, 1 ] $. previous researchers have established that, in the case of smooth kernels with piecewise polynomials of even degree, iteration in the collocation method and its variants improves the order of convergence by projection methods. in this article, we demonstrate the improvement in order of convergence by modified collocation method when the kernel is of green ' s function type.
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arxiv:2406.12343
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graph representation learning ( grl ) is a powerful technique for learning low - dimensional vector representation of high - dimensional and often sparse graphs. most studies explore the structure and metadata associated with the graph using random walks and employ an unsupervised or semi - supervised learning schemes. learning in these methods is context - free, resulting in only a single representation per node. recently studies have argued on the adequacy of a single representation and proposed context - sensitive approaches, which are capable of extracting multiple node representations for different contexts. this proved to be highly effective in applications such as link prediction and ranking. however, most of these methods rely on additional textual features that require complex and expensive rnns or cnns to capture high - level features or rely on a community detection algorithm to identify multiple contexts of a node. in this study we show that in - order to extract high - quality context - sensitive node representations it is not needed to rely on supplementary node features, nor to employ computationally heavy and complex models. we propose goat, a context - sensitive algorithm inspired by gossip communication and a mutual attention mechanism simply over the structure of the graph. we show the efficacy of goat using 6 real - world datasets on link prediction and node clustering tasks and compare it against 12 popular and state - of - the - art ( sota ) baselines. goat consistently outperforms them and achieves up to 12 % and 19 % gain over the best performing methods on link prediction and clustering tasks, respectively.
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arxiv:2004.00413
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we use the ads / cft duality to study the special point on the coulomb branch of $ { \ cal n } = 4 $ su ( n ) gauge theory which corresponds to a spherically symmetric shell of d3 - branes. this point is of interest both because the spacetime region inside the shell is flat, and because this configuration gives a very simple example of the transition between d - branes in the perturbative string regime and the non - perturbative regime of black holes. we discuss how this geometry is described in the dual gauge theory, through its effect on the two - point functions and wilson loops. in the calculation of the two - point function, we stress the importance of absorption by the branes.
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arxiv:hep-th/9907204
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in non - hermitian crystal systems under open boundary condition ( obc ), it is generally believed that the obc modes with frequencies containing positive imaginary parts, when excited by external driving, will experience exponential growth in population, thereby leading to instability. however, our work challenges this conventional understanding. in such a system, we find an anomalous response that grows exponentially with the frequency aligned with those of saddle points. the frequencies of these saddle points on the complex plane are below the maximum imaginary part of obc spectrum, but they can lie within or beyond the obc spectrum. we derive general formulas of excitation - response relationships and find that this anomalous response can occur because the excitation of obc modes eventually evolve toward these saddle points at long times. only when the frequencies of all these saddle points are below the real axis do the non - hermitian crystal systems remain stable under periodic excitation. thus our results also provide new insights on the stability criterion of non - hermitian crystal systems.
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arxiv:2406.19992
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surrogate models are of high interest for many engineering applications, serving as cheap - to - evaluate time - efficient approximations of black - box functions to help engineers and practitioners make decisions and understand complex systems. as such, the need for explainability methods is rising and many studies have been performed to facilitate knowledge discovery from surrogate models. to respond to these enquiries, this paper introduces smt - ex, an enhancement of the open - source python surrogate modeling toolbox ( smt ) that integrates explainability techniques into a state - of - the - art surrogate modelling framework. more precisely, smt - ex includes three key explainability methods : shapley additive explanations, partial dependence plot, and individual conditional expectations. a peculiar explainability dependency of smt has been developed for such purpose that can be easily activated once the surrogate model is built, offering a user - friendly and efficient tool for swift insight extraction. the effectiveness of smt - ex is showcased through two test cases. the first case is a 10 - variable wing weight problem with purely continuous variables and the second one is a 3 - variable mixed - categorical cantilever beam bending problem. relying on smt - ex analyses for these problems, we demonstrate its versatility in addressing a diverse range of problem characteristics. smt - explainability is freely available on github : https : / / github. com / smtorg / smt - explainability.
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arxiv:2503.19496
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softassign is a pivotal method in graph matching and other learning tasks. many softassign - based algorithms exhibit performance sensitivity to a parameter in the softassign. however, tuning the parameter is challenging and almost done empirically. this paper proposes an adaptive softassign method for graph matching by analyzing the relationship between the objective score and the parameter. this method can automatically tune the parameter based on a given error bound to guarantee accuracy. the hadamard - equipped sinkhorn formulas introduced in this study significantly enhance the efficiency and stability of the adaptive softassign. moreover, these formulas can also be used in optimal transport problems. the resulting adaptive softassign graph matching algorithm enjoys significantly higher accuracy than previous state - of - the - art large graph matching algorithms while maintaining comparable efficiency.
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arxiv:2309.13855
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we present herschel observations of 22 radio galaxies, selected for the presence of shocked, warm molecular hydrogen emission. we measured and modeled spectral energy distributions ( seds ) in 33 bands from the ultraviolet to the far - infrared to investigate the impact of jet feedback on star formation activity. these galaxies are massive, early - type galaxies with normal gas - to - dust ratios, covering a range of optical and infrared colors. we find that the star formation rate ( sfr ) is suppressed by a factor of ~ 3 - 6, depending on how molecular gas mass is estimated. we suggest this suppression is due to the shocks driven by the radio jets injecting turbulence into the interstellar medium ( ism ), which also powers the luminous warm h2 line emission. approximately 25 % of the sample shows suppression by more than a factor of 10. however, the degree of sfr suppression does not correlate with indicators of jet feedback including jet power, diffuse x - ray emission, or intensity of warm molecular h2 emission, suggesting that while injected turbulence likely impacts star formation, the process is not purely parameterized by the amount of mechanical energy dissipated into the ism. radio galaxies with shocked warm molecular gas cover a wide range in sfr - stellar mass space, indicating that these galaxies are in a variety of evolutionary states, from actively star - forming and gas - rich to quiescent and gas - poor. sfr suppression appears to have the largest impact on the evolution of galaxies that are moderately gas - rich.
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arxiv:1511.05968
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tracking controllers enable robotic systems to accurately follow planned reference trajectories. in particular, reinforcement learning ( rl ) has shown promise in the synthesis of controllers for systems with complex dynamics and modest online compute budgets. however, the poor sample efficiency of rl and the challenges of reward design make training slow and sometimes unstable, especially for high - dimensional systems. in this work, we leverage the inherent lie group symmetries of robotic systems with a floating base to mitigate these challenges when learning tracking controllers. we model a general tracking problem as a markov decision process ( mdp ) that captures the evolution of both the physical and reference states. next, we prove that symmetry in the underlying dynamics and running costs leads to an mdp homomorphism, a mapping that allows a policy trained on a lower - dimensional " quotient " mdp to be lifted to an optimal tracking controller for the original system. we compare this symmetry - informed approach to an unstructured baseline, using proximal policy optimization ( ppo ) to learn tracking controllers for three systems : the particle ( a forced point mass ), the astrobee ( a fullyactuated space robot ), and the quadrotor ( an underactuated system ). results show that a symmetry - aware approach both accelerates training and reduces tracking error at convergence.
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arxiv:2409.11238
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brezis and mironescu have announced several years ago that for a compact manifold $ n ^ n \ subset \ mathbb { r } ^ \ nu $ and for real numbers $ 0 < s < 1 $ and $ 1 \ le p < \ infty $ the class $ c ^ \ infty ( \ overline { q } ^ m ; n ^ n ) $ of smooth maps on the cube with values into $ n ^ n $ is dense with respect to the strong topology in the sobolev space $ w ^ { s, p } ( q ^ m ; n ^ n ) $ when the homotopy group $ \ pi _ { \ lfloor sp \ rfloor } ( n ^ n ) $ of order $ \ lfloor sp \ rfloor $ is trivial. the proof of this beautiful result is long and rather involved. under the additional assumption that $ n ^ n $ is $ \ lfloor sp \ rfloor $ simply connected, we give a shorter proof of their result. our proof for $ sp \ ge 1 $ is based on the existence of a retraction of $ \ mathbb { r } ^ \ nu $ onto $ n ^ n $ except for a small subset in the complement of $ n ^ n $ and on the gagliardo - nirenberg interpolation inequality for maps in $ w ^ { 1, q } \ cap l ^ \ infty $. in contrast, the case $ sp < 1 $ relies on the density of step functions on cubes in $ w ^ { s, p } $.
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arxiv:1310.6017
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a { \ em leader election } algorithm is an elimination process that divides recursively into tow subgroups an initial group of n items, eliminates one subgroup and continues the procedure until a subgroup is of size 1. in this paper the biased case is analyzed. we are interested in the { \ em cost } of the algorithm, i. e. the number of operations needed until the algorithm stops. using a probabilistic approach, the asymptotic behavior of the algorithm is shown to be related to the behavior of a hitting time of two random sequences on [ 0, 1 ].
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arxiv:cs/0702056
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