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stringlengths 18
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| categories
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| creation_date
timestamp[ns, tz=UTC] |
|---|---|---|---|---|
1607.03437
|
A note on quasi generalized CR-lightlike geometry in indefinite nearly $\mu$-Sasakian manifold
|
The concept of quasi generalized CR-lightlike was first introduced by the authors in [18]. In this paper, we focus on ascreen and co-screen quasi generalized CR-lightlike submanifolds of indefinite nearly $\mu$-Sasakian manifold. We prove an existence theorem for minimal ascreen quasi generalized CR-lightlike submanifolds admitting a metric connection. Classification theorems on nearly parallel and auto-parallel distributions on a co-screen quasi generalized CR-lightlike submanifold are also given. Several examples are also constructed, where necessary, to illustrate the main ideas.
|
[
"Mathematics Archive->math.DG"
] | 2016-07-07T05:13:40Z |
2311.12494
|
Successive Incentives
|
We study the design of optimal incentives in sequential processes. To do so, we consider a basic and fundamental model in which an agent initiates a value-creating sequential process through costly investment with random success. If unsuccessful, the process stops. If successful, a new agent thereafter faces a similar investment decision, and so forth. For any outcome of the process, the total value is distributed among the agents using a reward rule. Reward rules thus induce a game among the agents. By design, the reward rule may lead to an asymmetric game, yet we are able to show equilibrium existence with optimal symmetric equilibria. We characterize optimal reward rules that yield the highest possible welfare created by the process, and the highest possible expected payoff for the initiator of the process. Our findings show that simple reward rules invoking short-run incentives are sufficient to meet long-run objectives.
|
[
"Economics Archive->econ.TH"
] | 2023-11-21T10:10:49Z |
2308.05675
|
Erd\H{o}s-Gy\'{a}rf\'{a}s Conjecture for $P_{10}$-free Graphs
|
Let $P_{10}$ be a path on $10$ vertices. A graph is said to be $P_{10}$-free if it does not contain $P_{10}$ as an induced subgraph. The well-known Erd\H{o}s-Gy\'{a}rf\'{a}s Conjecture states that every graph with minimum degree at least three has a cycle whose length is a power of $2$. In this paper, we show that every $P_{10}$-free graph with minimum degree at least three contains a cycle of length $4$ or $8$. This implies that the conjecture is true for $P_{10}$-free graphs.
|
[
"Mathematics Archive->math.CO"
] | 2023-08-10T16:23:39Z |
2204.11897
|
Reinforcement Teaching
|
Meta-learning strives to learn about and improve a student's machine learning algorithm. However, existing meta-learning methods either only work with differentiable algorithms or are hand-crafted to improve one specific component of an algorithm. We develop a unifying meta-learning framework, called Reinforcement Teaching, to improve the learning process of any algorithm. Under Reinforcement Teaching, a teaching policy is learned, through reinforcement, to improve a student's learning. To effectively learn such a teaching policy, we introduce a parametric-behavior embedder that learns a representation of the student's learnable parameters from its input/output behavior. Further, we use learning progress to shape the teacher's reward, allowing it to more quickly maximize the student's performance. To demonstrate the generality of Reinforcement Teaching, we conduct experiments where a teacher learns to significantly improve both reinforcement and supervised learning algorithms, outperforming hand-crafted heuristics and previously proposed parameter representations. Results show that Reinforcement Teaching is capable of not only unifying different meta-learning approaches, but also effectively leveraging existing tools from reinforcement learning research.
|
[
"Computer Science Archive->cs.LG"
] | 2022-04-25T18:04:17Z |
1309.4369
|
Cavity-Assisted Dynamical Spin-Orbit Coupling in Cold Atoms
|
We consider ultracold atoms subjected to a cavity-assisted two-photon Raman transition. The Raman coupling gives rise to effective spin-orbit interaction which couples atom's center-of-mass motion to its pseudospin degrees of freedom. Meanwhile, the cavity photon is dynamically affected by the atom. This feedback between atom and photon leads to a dramatic modification of the atomic dispersion relation, and further leads to dynamical instability of the system. We propose to detect the change of cavity photon number as a direct way to demonstrate dynamical instability.
|
[
"Physics Archive->cond-mat->cond-mat.quant-gas"
] | 2013-09-17T16:16:21Z |
1802.04996
|
The algebraic de Rham realization of the elliptic polylogarithm via the Poincar\'e bundle
|
In this paper, we describe the algebraic de Rham realization of the elliptic polylogarithm for arbitrary families of elliptic curves in terms of the Poincar\'e bundle. Our work builds on previous work of Scheider and generalizes results of Bannai-Kobayashi-Tsuji and Scheider. As an application, we compute the de Rham Eisenstein classes explicitly in terms of certain algebraic Eisenstein series.
|
[
"Mathematics Archive->math.NT"
] | 2018-02-14T09:12:37Z |
cond-mat/0208348
|
Supercurrent-carrying density of states in diffusive mesoscopic Josephson weak links
|
Recent experiments have demonstrated the nonequilibrium control of the supercurrent through diffusive phase-coherent normal-metal weak links. The experimental results have been accurately described by the quasiclassical Green's function technique in the Keldysh formalism. Taking into account the geometry of the structure, different energy scales and the nonidealities at the interfaces allows us to obtain a quantitative agreement between the theory and the experimental results in both the amplitude and the phase dependence of the supercurrent, with no or very few fitting parameters. Here we discuss the most important factors involved with such comparisons: the ratio between the superconducting order parameter and the Thouless energy of the junction, the effect of additional wires on the weak link, and the effects due to imperfections, most notably due to the nonideal interfaces.
|
[
"Physics Archive->cond-mat->cond-mat.mes-hall",
"Physics Archive->cond-mat->cond-mat.supr-con"
] | 2002-08-18T20:18:39Z |
1409.0259
|
No evidence of chemical anomalies in the bimodal turnoff cluster NGC 1806 in the LMC
|
We have studied the chemical composition of NGC 1806, a massive, intermediate-age globular cluster that shows a double main sequence turnoff. We analyzed a sample of high-resolution spectra (secured with FLAMES at the Very Large Telescope) for 8 giant stars, members of the cluster, finding an average iron content of [Fe/H]=--0.60 +- 0.01 dex and no evidence of intrinsic star-to-star variations in the abundances of light elements (Na, O, Mg, Al). Also, the (m_(F814W); m_(F336W)-m_(F814W)) color-magnitude diagram obtained by combining optical and near-UV Hubble Space Telescope photometry exhibits a narrow red giant branch, thus ruling out intrinsic variations of C and N abundances in the cluster. These findings demonstrate that NGC 1806 does not harbor chemically distinct sub-populations, at variance with what was found in old globular clusters. In turn, this indicates that the double main sequence turnoff phenomenon cannot be explained in the context of the self-enrichment processes usually invoked to explain the chemical anomalies observed in old globulars. Other solutions (i.e., stellar rotation, merging between clusters or collisions with giant molecular clouds) should be envisaged to explain this class of globulars.
|
[
"Physics Archive->astro-ph->astro-ph.SR"
] | 2014-08-31T20:00:03Z |
0704.3455
|
The Distribution of AGN in Clusters of Galaxies
|
We present a study of the distribution of AGN in clusters of galaxies with a uniformly selected, spectroscopically complete sample of 35 AGN in eight clusters at z = 0.06 to 0.31. We find that the 12 AGN with L_X > 10^42 erg/s in galaxies more luminous than a rest-frame M_R < -20 mag are more centrally concentrated than typical cluster galaxies of this luminosity, although these AGN have comparable velocity and substructure distributions to other cluster members. In contrast, a larger sample of 30 cluster AGN with L_X > 10^41 erg/s do not show evidence for greater concentration than inactive members, nor evidence for a different kinematic or substructure distribution. As we do see clear differences in the spatial and kinematic distributions of the blue Butcher-Oemler and red galaxy populations, any difference in the AGN and inactive galaxy population must be less distinct than that between these two pairs of populations. Comparison of the AGN fraction selected via X-ray emission in this study to similarly-selected AGN in the field indicates that the AGN fraction is not significantly lower in clusters, contrary to AGN identified via visible-wavelength emission lines, but similar to the approximately constant radio-selected AGN fraction in clusters and the field. We also find significant evidence for variation between clusters and explore the dependence of cluster AGN fraction on redshift, velocity dispersion, cluster substructure, and Butcher-Oemler fraction. While we see weak evidence for several trends, correlations between these four parameters in our small sample precludes identification of which one(s) most strongly influence the cluster AGN fraction.
|
[
"Physics Archive->astro-ph"
] | 2007-04-25T21:40:26Z |
2302.09422
|
Neural Attention Memory
|
We propose a novel perspective of the attention mechanism by reinventing it as a memory architecture for neural networks, namely Neural Attention Memory (NAM). NAM is a memory structure that is both readable and writable via differentiable linear algebra operations. We explore three use cases of NAM: memory-augmented neural network (MANN), few-shot learning, and efficient long-range attention. First, we design two NAM-based MANNs of Long Short-term Memory (LSAM) and NAM Turing Machine (NAM-TM) that show better computational powers in algorithmic zero-shot generalization tasks compared to other baselines such as differentiable neural computer (DNC). Next, we apply NAM to the N-way K-shot learning task and show that it is more effective at reducing false positives compared to the baseline cosine classifier. Finally, we implement an efficient Transformer with NAM and evaluate it with long-range arena tasks to show that NAM can be an efficient and effective alternative for scaled dot-product attention.
|
[
"Computer Science Archive->cs.LG"
] | 2023-02-18T21:19:21Z |
hep-lat/0702014
|
Light dynamical fermions on the lattice: toward the chiral regime of QCD
|
Algorithmic and technical progress achieved over the last few years makes QCD simulations with light dynamical quarks much faster than before. As a result lattices with pions as light as 250--300 MeV can be simulated with the present generation of computers. I review recent conceptual and numerical progress in this field, with particular emphasis on results obtained and difficulties encountered in simulations with significantly smaller quark masses with respect to previous computations. I also attempt to compare physical results for pion masses and decay constants available to date in the two-flavour theory with expectations from chiral perturbation theory.
|
[
"Physics Archive->hep->hep-lat"
] | 2007-02-08T18:10:53Z |
2209.02680
|
Design and upgrade of the prototype Schwarzschild-Couder Telescope
|
The Cherenkov Telescope Array (CTA) is the next-generation ground-based observatory for very-high energy gamma-ray astronomy. CTA will have unparalleled sensitivity and angular resolution and will detect gamma-ray sources nearly 100 times faster than current arrays, enabling valuable multiwavelength and multimessenger observations. The Schwarzschild-Couder Telescope (SCT) is a candidate for the Medium-Sized telescope in CTA. A prototype SCT (pSCT) has been constructed at the Fred Lawrence Whipple Observatory in Arizona USA. Its camera is currently partially instrumented with 1600 pixels (2.7 degree FOV). The small plate scale of the optical system allows densely packed silicon photomultipliers to be used, which combined with high-density trigger and waveform readout electronics enable the high-resolution camera. The camera's electronics are capable of imaging air shower development with waveform readout with nanosecond resolution. The pSCT was inaugurated in January 2019, with commissioning continuing throughout that year. The first campaign of observations with the pSCT was conducted in January and February of 2020. Gamma-ray emission from the Crab Nebula was detected with a significance of 8.6 sigma. An upgrade to the pSCT camera is currently underway. The upgrade will fully populate the focal plane, increasing the field of view to 8 degrees diameter, and lower the front-end electronics noise, enabling a lower trigger threshold and improved reconstruction and background rejection.
|
[
"Physics Archive->astro-ph->astro-ph.IM"
] | 2022-09-06T17:50:58Z |
1012.5759
|
Statistically Quasi-Cauchy Sequences
|
This paper is withdrawn because the results in the paper are included in a paper to be published in Mathematical and Computer Modelling.
|
[
"Mathematics Archive->math.GN"
] | 2010-12-28T13:35:17Z |
0905.3133
|
Catalyst-free selective area growth of InN nanocolumns by MBE
|
Selective area growth of InN nanorods by plasma assisted molecular beam epitaxy is demonstrated. Molybdenum is found to be a suitable mask material at the low substrate temperature of 475 C needed for the growth of InN nanocolumns. The growth of arrays of single nanorods on a Si(111) substrate has been achieved with a thin molybdenum mask lithographically patterned with holes smaller than 60 nm.
|
[
"Physics Archive->cond-mat->cond-mat.mes-hall",
"Physics Archive->cond-mat->cond-mat.mtrl-sci"
] | 2009-05-19T15:22:52Z |
1101.1620
|
Addendum to "Spherical structures on torus knots and links"
|
The present paper is an addendum to "Spherical structures on torus knots and links", arXiv:1008.0312, and concerns more general case of torus knot and link cone-manifolds.
|
[
"Mathematics Archive->math.GT"
] | 2011-01-08T20:47:14Z |
1901.02800
|
Some adaptive proximal method for a special class of variational inequalities and related problems
|
An adaptive proximal method for a special class of variational inequalities and related problems is proposed. For example, the so-called mixed variational inequalities and composite saddle problems are considered. Some estimates of the necessary number of iterations are obtained to achieve a given quality of the solution.
|
[
"Mathematics Archive->math.OC"
] | 2019-01-09T16:06:20Z |
2204.06856
|
A consistent approach to the path integral formalism of quantum mechanics based on the maximum length uncertainty
|
We have developed a proper path integral formalism consistent with the deformed version of the quantum mechanics which contains a maximum observable length scale at the order of the Cosmological particle horizon, existing in cosmology. First, we have presented the modifications to the classical mechanics which shows non-minimal effects on the equation of motion of a particle. Next, we have provided representation of the deformed quantum mechanical algebra. With this algebra in hand, we have calculated the general form of the path integral propagator in this deformed background. Finally, as a most simple case, we have built up the explicit form of the free particle propagator. The modifications to the free particle propagator shows some non-trivial effects in this case, which can have some important significance.
|
[
"Mathematics Archive->math.MP",
"Physics Archive->gr-qc",
"Physics Archive->hep->hep-th",
"Physics Archive->math-ph"
] | 2022-04-14T10:09:59Z |
1312.4932
|
Application of Remote Sensing, GIS and GPS for efficient Urban Management Plan, A case study of part of Hyderabad city
|
Role of urban planning and management in Hyderabad is becoming more and more crucial due to the dramatic increase in urban population and allied urban problems. Hyderabad is experiencing a rapid urbanization rate. Urbanization contributes many advantages in terms of economics, but if uncontrolled, would produce negative consequences to the physical, social and natural environment. With the advancement of GIS, which considerably influenced the dynamic nature of urban and regional planning, incorporation of GIS becomes imperative for better and improved decision-making in urban planning and management. It offers a solution to the urban problems and decision-making, which is more reliant to the real-time spatial modelling. The integration of Geographical Information System (GIS) and Remote Sensing has provided a tool, which can contribute to much clearer understanding of real planning problems as well as prescriptive planning scenarios to enhance the quality of urban planning and management.
|
[
"Computer Science Archive->cs.CY"
] | 2013-12-17T20:43:39Z |
hep-ph/0212301
|
Singular Cross Sections in Muon Colliders
|
We address the problem that the cross section for the collisions of unstable particles diverges, if calculated by standard methods. This problem is considered for beams much smaller than the decay length of the unstable particle, much larger than the decay length and finally also for pancake- shaped beams. We find that in all cases this problem can be solved by taking into account the production/propagation of the unstable particle and/or the width of the incoming wave packets in momentum space.
|
[
"Physics Archive->hep->hep-ph"
] | 2002-12-19T19:24:05Z |
2206.09285
|
Q-linear Convergence of Distributed Optimization with Barzilai-Borwein Step Sizes
|
The growth in sizes of large-scale systems and data in machine learning have made distributed optimization a naturally appealing technique to solve decision problems in different contexts. In such methods, each agent iteratively carries out computations on its local objective using information received from its neighbors, and shares relevant information with neighboring agents. Though gradient-based methods are widely used because of their simplicity, they are known to have slow convergence rates. On the other hand, though Newton-type methods have better convergence properties, they are not as applicable because of the enormous computation and memory requirements. In this work, we introduce a distributed quasi-Newton method with Barzilai-Borwein step-sizes. We prove a Q-linear convergence to the optimal solution, present conditions under which the algorithm is superlinearly convergent and validate our results via numerical simulations.
|
[
"Computer Science Archive->cs.SY",
"Electrical Engineering and Systems Science Archive->eess.SY",
"Mathematics Archive->math.OC"
] | 2022-06-18T21:49:58Z |
1510.08198
|
Effect of ambient on the resistance fluctuations of graphene
|
In this letter we present the results of systematic experimental investigations of the effect of different chemical environments on the low frequency resistance fluctuations of single layer graphene field effect transistors (SLG-FET). The shape of the power spectral density of noise was found to be determined by the energetics of the adsorption-desorption of molecules from the graphene surface making it the dominant source of noise in these devices. We also demonstrate a method of quantitatively determining the adsorption energies of chemicals on graphene surface based on noise measurements. We find that the magnitude of noise is extremely sensitive to the nature and amount of the chemical species present. We propose that a chemical sensor based on the measurement of low frequency resistance fluctuations of single layer graphene field effect transistor devices will have extremely high sensitivity, very high specificity, high fidelity and fast response times.
|
[
"Physics Archive->cond-mat->cond-mat.mes-hall"
] | 2015-10-28T06:00:34Z |
2102.00827
|
Automatic Expansion of Domain-Specific Affective Models for Web Intelligence Applications
|
Sentic computing relies on well-defined affective models of different complexity - polarity to distinguish positive and negative sentiment, for example, or more nuanced models to capture expressions of human emotions. When used to measure communication success, even the most granular affective model combined with sophisticated machine learning approaches may not fully capture an organisation's strategic positioning goals. Such goals often deviate from the assumptions of standardised affective models. While certain emotions such as Joy and Trust typically represent desirable brand associations, specific communication goals formulated by marketing professionals often go beyond such standard dimensions. For instance, the brand manager of a television show may consider fear or sadness to be desired emotions for its audience. This article introduces expansion techniques for affective models, combining common and commonsense knowledge available in knowledge graphs with language models and affective reasoning, improving coverage and consistency as well as supporting domain-specific interpretations of emotions. An extensive evaluation compares the performance of different expansion techniques: (i) a quantitative evaluation based on the revisited Hourglass of Emotions model to assess performance on complex models that cover multiple affective categories, using manually compiled gold standard data, and (ii) a qualitative evaluation of a domain-specific affective model for television programme brands. The results of these evaluations demonstrate that the introduced techniques support a variety of embeddings and pre-trained models. The paper concludes with a discussion on applying this approach to other scenarios where affective model resources are scarce.
|
[
"Computer Science Archive->cs.IR",
"Computer Science Archive->cs.LG"
] | 2021-02-01T13:32:35Z |
2209.01917
|
Two-Spacecraft Detection of Short-period Decayless Kink Oscillations of Solar Coronal Loops
|
Decayless kink oscillations of an ensemble of loops are captured simultaneously by the High Resolution Imager (HRI) of the Extreme Ultraviolet Imager (EUI) and the Atmospheric Imaging Assembly (AIA) from 22:58 UT on 5 November to 00:27 UT on 6 November 2021. Oscillations are analysed by processing image sequences taken by the two instruments with a motion magnification technique. The analysed loops are around 51 Mm in length, and oscillate with short periods of 1-3 min (1.6 min in average) and displacement amplitudes of 27-83 km. The signals recorded by AIA are delayed by 66 s as compared to HRI, which coincides with the light travel time difference from the Sun to each instrument. After correction of this time difference, the cross-correlation coefficient between the signals from the two data varies from 0.82 to 0.97, indicating that they are well consistent. This work confirms that HRI sees the same oscillations as AIA, which is the necessary first step before proceeding to the detection of shorter time scales by EUI. In addition, our results indicate the robustness of the de-jittering procedure in the study of kink oscillations with HRI.
|
[
"Physics Archive->astro-ph->astro-ph.SR"
] | 2022-09-05T12:05:06Z |
hep-ph/0312252
|
The jet quenching in high energy nuclear collisions and quark-gluon plasma
|
e investigate the energy loss of quark and gluon jets in quark-gluon plasma produced in central Au+Au collisions at RHIC energy. We use the physical characteristic of initial and mixed phases, which were found in effective quasiparticle model for SPS and RHIC energy. At investigation of energy loss we take into account also the production of hot glue at first stage. The energy loss in expanding plasma is calculated in dominant first order of radiation intensity with accounting of finite kinematic bounds. We calculate the suppression of $\pi^0$ - spectra with moderate high $p_{\perp}$, which is caused by energy loss of quark and gluon jets. The comparison with suppression of $\pi^0$ reported by PHENIX show, that correct quantitative description of suppression we have only in model of phase transition with decrease of thermal gluon mass and effective coupling $G(T)$ in region of phase transition plasma into hadrons (at $T \simeq T_c$). However quasiparticle model with increase of these values at $T \to T_c$ in accordance with perturbative QCD lead to too great energy loss of gluon and quark jets, which disagrees with data on suppression of $\pi^0$. Thus it is possible with help of hard processes to investigate the structure of phase transition. We show also, that energy losses at SPS energy are too small in order to be observable. This is caused in fact by sufficiently short plasma phase at this energy.
|
[
"Physics Archive->hep->hep-ph"
] | 2003-12-18T08:58:42Z |
1805.11234
|
Table-to-Text: Describing Table Region with Natural Language
|
In this paper, we present a generative model to generate a natural language sentence describing a table region, e.g., a row. The model maps a row from a table to a continuous vector and then generates a natural language sentence by leveraging the semantics of a table. To deal with rare words appearing in a table, we develop a flexible copying mechanism that selectively replicates contents from the table in the output sequence. Extensive experiments demonstrate the accuracy of the model and the power of the copying mechanism. On two synthetic datasets, WIKIBIO and SIMPLEQUESTIONS, our model improves the current state-of-the-art BLEU-4 score from 34.70 to 40.26 and from 33.32 to 39.12, respectively. Furthermore, we introduce an open-domain dataset WIKITABLETEXT including 13,318 explanatory sentences for 4,962 tables. Our model achieves a BLEU-4 score of 38.23, which outperforms template based and language model based approaches.
|
[
"Computer Science Archive->cs.AI",
"Computer Science Archive->cs.CL"
] | 2018-05-29T03:39:35Z |
2205.00967
|
Monocular 3D Fingerprint Reconstruction and Unwarping
|
Compared with contact-based fingerprint acquisition techniques, contactless acquisition has the advantages of less skin distortion, larger fingerprint area, and hygienic acquisition. However, perspective distortion is a challenge in contactless fingerprint recognition, which changes ridge orientation, frequency, and minutiae location, and thus causes degraded recognition accuracy. We propose a learning based shape from texture algorithm to reconstruct a 3D finger shape from a single image and unwarp the raw image to suppress perspective distortion. Experimental results on contactless fingerprint databases show that the proposed method has high 3D reconstruction accuracy. Matching experiments on contactless-contact and contactless-contactless matching prove that the proposed method improves matching accuracy.
|
[
"Computer Science Archive->cs.CV"
] | 2022-05-02T15:09:05Z |
1907.12082
|
Effects of resource competition on evolution and adaptive radiation
|
The entanglement of population dynamics, evolution, and adaptive radiation for species competing for resources is studied. For resource harvesting, we modify the model used in Ref. Phys. Rev. Lett. 118 048103 and introduce new resource contest principles. We realistically implement the effects of beneficial and deleterious mutations on the coefficients in the equations governing the population dynamics and consider the emergence of reproductive isolation. The proposed model is shown to be in agreement with the competitive exclusion principle and no vacant niche principle. We establish a mechanism that contributes to preventing the accumulation of irreversible deleterious mutations: competition between recently diverged species/subpopulations. The proposed model is applicable for descriptions of more complex systems. In case of many constants in time resources, one observes very rapid specialization, a feature not reproducible by the common model.
|
[
"Quantitative Biology Archive->q-bio.PE"
] | 2019-07-28T13:58:43Z |
2307.11677
|
Improved Approximate Distance Oracles: Bypassing the Thorup-Zwick Bound in Dense Graphs
|
Despite extensive research on distance oracles, there are still large gaps between the best constructions for spanners and distance oracles. Notably, there exist sparse spanners with a multiplicative stretch of $1+\varepsilon$ plus some additive stretch. A fundamental open problem is whether such a bound is achievable for distance oracles as well. Specifically, can we construct a distance oracle with multiplicative stretch better than 2, along with some additive stretch, while maintaining subquadratic space complexity? This question remains a crucial area of investigation, and finding a positive answer would be a significant step forward for distance oracles. Indeed, such oracles have been constructed for sparse graphs. However, in the more general case of dense graphs, it is currently unknown whether such oracles exist. In this paper, we contribute to the field by presenting the first distance oracles that achieve a multiplicative stretch of $1+\varepsilon$ along with a small additive stretch while maintaining subquadratic space complexity. Our results represent an advancement particularly for constructing efficient distance oracles for dense graphs. In addition, we present a whole family of oracles that, for any positive integer $k$, achieve a multiplicative stretch of $2k-1+\varepsilon$ using $o(n^{1+1/k})$ space.
|
[
"Computer Science Archive->cs.DS"
] | 2023-07-21T16:29:50Z |
1912.13070
|
Singular vectors on manifolds and fractals
|
We generalize Khintchine's method of constructing totally irrational singular vectors and linear forms. The main result of the paper shows existence of totally irrational vectors and linear forms with large uniform Diophantine exponents on certain subsets of $\mathbb{R}^n$, in particular on any analytic submanifold of $\mathbb{R}^n$ of dimension $\ge 2$ which is not contained in a proper rational affine subspace.
|
[
"Mathematics Archive->math.DS",
"Mathematics Archive->math.NT"
] | 2019-12-30T19:57:34Z |
2204.13062
|
Collaborative Learning for Hand and Object Reconstruction with Attention-guided Graph Convolution
|
Estimating the pose and shape of hands and objects under interaction finds numerous applications including augmented and virtual reality. Existing approaches for hand and object reconstruction require explicitly defined physical constraints and known objects, which limits its application domains. Our algorithm is agnostic to object models, and it learns the physical rules governing hand-object interaction. This requires automatically inferring the shapes and physical interaction of hands and (potentially unknown) objects. We seek to approach this challenging problem by proposing a collaborative learning strategy where two-branches of deep networks are learning from each other. Specifically, we transfer hand mesh information to the object branch and vice versa for the hand branch. The resulting optimisation (training) problem can be unstable, and we address this via two strategies: (i) attention-guided graph convolution which helps identify and focus on mutual occlusion and (ii) unsupervised associative loss which facilitates the transfer of information between the branches. Experiments using four widely-used benchmarks show that our framework achieves beyond state-of-the-art accuracy in 3D pose estimation, as well as recovers dense 3D hand and object shapes. Each technical component above contributes meaningfully in the ablation study.
|
[
"Computer Science Archive->cs.CV"
] | 2022-04-27T17:00:54Z |
1009.4943
|
Primitive orthogonal idempotents for R-trivial monoids
|
We construct a recursive formula for a complete system of primitive orthogonal idempotents for any $R$-trivial monoid. This uses the newly proved equivalence between the notions of $R$-trivial monoid and weakly ordered monoid.
|
[
"Mathematics Archive->math.RT"
] | 2010-09-24T20:43:14Z |
1909.01567
|
A Non-commutative Bilinear Model for Answering Path Queries in Knowledge Graphs
|
Bilinear diagonal models for knowledge graph embedding (KGE), such as DistMult and ComplEx, balance expressiveness and computational efficiency by representing relations as diagonal matrices. Although they perform well in predicting atomic relations, composite relations (relation paths) cannot be modeled naturally by the product of relation matrices, as the product of diagonal matrices is commutative and hence invariant with the order of relations. In this paper, we propose a new bilinear KGE model, called BlockHolE, based on block circulant matrices. In BlockHolE, relation matrices can be non-commutative, allowing composite relations to be modeled by matrix product. The model is parameterized in a way that covers a spectrum ranging from diagonal to full relation matrices. A fast computation technique is developed on the basis of the duality of the Fourier transform of circulant matrices.
|
[
"Computer Science Archive->cs.AI",
"Computer Science Archive->cs.CL"
] | 2019-09-04T06:26:05Z |
math/0405136
|
Order ideals in weak subposets of Young's lattice and associated unimodality conjectures
|
The k-Young lattice Y^k is a weak subposet of the Young lattice containing partitions whose first part is bounded by an integer k>0. The Y^k poset was introduced in connection with generalized Schur functions and later shown to be isomorphic to the weak order on the quotient of the affine symmetric group by a maximal parabolic subgroup. We prove a number of properties for $Y^k$ including that the covering relation is preserved when elements are translated by rectangular partitions with hook-length $k$. We highlight the order ideal generated by an $m\times n$ rectangular shape. This order ideal, L^k(m,n), reduces to L(m,n) for large k, and we prove it is isomorphic to the induced subposet of L(m,n) whose vertex set is restricted to elements with no more than k-m+1 parts smaller than m. We provide explicit formulas for the number of elements and the rank-generating function of L^k(m,n). We conclude with unimodality conjectures involving q-binomial coefficients and discuss how implications connect to recent work on sieved q-binomial coefficients.
|
[
"Mathematics Archive->math.CO"
] | 2004-05-07T18:48:10Z |
2308.07204
|
Algorithms for the Training of Neural Support Vector Machines
|
Neural support vector machines (NSVMs) allow for the incorporation of domain knowledge in the design of the model architecture. In this article we introduce a set of training algorithms for NSVMs that leverage the Pegasos algorithm and provide a proof of concept by solving a set of standard machine learning tasks.
|
[
"Computer Science Archive->cs.AI",
"Computer Science Archive->cs.LG"
] | 2023-08-14T15:16:39Z |
1310.8317
|
Power of Nondetreministic JAGs on Cayley graphs
|
The Immerman-Szelepcsenyi Theorem uses an algorithm for co-st- connectivity based on inductive counting to prove that NLOGSPACE is closed un- der complementation. We want to investigate whether counting is necessary for this theorem to hold. Concretely, we show that Nondeterministic Jumping Graph Autmata (ND-JAGs) (pebble automata on graphs), on several families of Cayley graphs, are equal in power to nondeterministic logspace Turing machines that are given such graphs as a linear encoding. In particular, it follows that ND-JAGs can solve co-st-connectivity on those graphs. This came as a surprise since Cook and Rackoff showed that deterministic JAGs cannot solve st-connectivity on many Cayley graphs due to their high self-similarity (every neighbourhood looks the same). Thus, our results show that on these graphs, nondeterminism provably adds computational power. The families of Cayley graphs we consider include Cayley graphs of abelian groups and of all finite simple groups irrespective of how they are presented and graphs corresponding to groups generated by various product constructions, in- cluding iterated ones. We remark that assessing the precise power of nondeterministic JAGs and in par- ticular whether they can solve co-st-connectivity on arbitrary graphs is left as an open problem by Edmonds, Poon and Achlioptas. Our results suggest a positive answer to this question and in particular considerably limit the search space for a potential counterexample.
|
[
"Computer Science Archive->cs.CC"
] | 2013-10-30T20:44:03Z |
2210.09376
|
Vecchia Approximations and Optimization for Multivariate Mat\'ern Models
|
We describe our implementation of the multivariate Mat\'ern model for multivariate spatial datasets, using Vecchia's approximation and a Fisher scoring optimization algorithm. We consider various pararameterizations for the multivariate Mat\'ern that have been proposed in the literature for ensuring model validity, as well as an unconstrained model. A strength of our study is that the code is tested on many real-world multivariate spatial datasets. We use it to study the effect of ordering and conditioning in Vecchia's approximation and the restrictions imposed by the various parameterizations. We also consider a model in which co-located nuggets are correlated across components and find that forcing this cross-component nugget correlation to be zero can have a serious impact on the other model parameters, so we suggest allowing cross-component correlation in co-located nugget terms.
|
[
"Statistics Archive->stat.CO",
"Statistics Archive->stat.ME"
] | 2022-10-17T19:19:29Z |
0806.4582
|
Velocity oscillations in confined channel flows of concentrated colloidal suspensions
|
We study the pressure-driven flow of concentrated colloids confined in glass micro-channels at the single particle level using fast confocal microscopy. For channel to particle size ratios $a/\bar{D} \lesssim 30$, the flow rate of the suspended particles shows fluctuations. These turn into regular oscillations for higher confinements ($a/\bar{D} \simeq 20$). We present evidence to link these oscillations with the relative flow of solvent and particles (permeation) and the effect of confinement on shear thickening.
|
[
"Physics Archive->cond-mat->cond-mat.soft"
] | 2008-06-27T17:41:19Z |
1206.6376
|
An Ancient Metal-Poor Population in M32, and Halo Satellite Accretion in M31, Identified by RR Lyrae Stars
|
We present time-series photometry of two fields near M32 using archival observations from ACS/WFC onboard HST. One field is centered about 2 arcmin from M32 while the other is located 15 arcmin to the southeast of M31. We identify a total of 1139 RR Lyrae variables of which 821 are ab-type and 318 are c-type. In the field near M32, we find a radial gradient in the density of RR Lyraes relative to the center of M32. This gradient is consistent with the surface brightness profile of M32 suggesting that a significant number of the RR Lyraes in this region belong to M32. This provides further confirmation that M32 contains an ancient stellar population formed around the same time as the oldest population in M31 and the Milky Way. The RR Lyrae stars in M32 exhibit a mean metal abundance of [Fe/H] ~ -1.42 +/- 0.02, which is ~15 times lower than the metal abundance of the overall M32 stellar population. Moreover, the abundance of RR Lyrae stars normalized to the luminosity of M32 in the field analyzed further indicates that the ancient metal-poor population in M32 represents only a very minor component of this galaxy, consistent with the 1% to 4.5% in mass inferred from the CMD analysis of Monachesi et al. In the other field, we find unprecedented evidence for two populations of RR Lyraes in M31 as shown by two distinct sequences among the ab-type variables in the Bailey Diagram. When interpreted in terms of metal abundance, one population exhibits a peak at [Fe/H] ~ -1.3 and the other is at [Fe/H] ~ -1.9. One possible interpretation of this result is that the more metal-rich population represents the dominant M31 halo, while the metal-poorer group could be a disrupted dwarf satellite galaxy orbiting M31. If true, this represents a further indication that the formation of the M31 spheroid has been significantly influenced by the merger and accretion of dwarf galaxy satellites. [abridged]
|
[
"Physics Archive->astro-ph->astro-ph.GA",
"Physics Archive->astro-ph->astro-ph.SR"
] | 2012-06-27T19:55:33Z |
0708.2104
|
Internal Secular Evolution in Disk Galaxies: The Growth of Pseudobulges
|
Observational and theoretical evidence that internal, slow ("secular") evolution reshapes galaxy disks is reviewed in Kormendy & Kennicutt (2004, ARAA, 42, 603). This update has three aims. First, I emphasize that this evolution is very general -- it is as fundamental to the evolution of galaxy disks as (e.g.) core collapse is to globular clusters, as the production of hot Jupiters is to the evolution of protoplanetary disks, and as evolution to red giants containing proto-white-dwarfs is to stellar evolution. One consequence for disk galaxies is the buildup of dense central components that get mistaken for classical (i.e., merger-built) bulges but that were grown out of disk stars and gas. We call these pseudobulges. Second, I review new results on pseudobulge star formation and structure and on the distinction between boxy and disky pseudobulges. Finally, I highlight how these results make a galaxy formation problem more acute. How can hierarchical clustering produce so many pure disk galaxies with no evidence for merger-built bulges?
|
[
"Physics Archive->astro-ph"
] | 2007-08-15T20:56:18Z |
2208.08854
|
Energy Constraints for Evolving Spherical and Hyperbolic Wormholes in $f(R,T)$ Gravity
|
The primary objective of this article is to study the energy condition bounds for spherical and hyperbolic wormholes in well-known $f(R,T)$ theory of gravity. For this purpose, we formulate the field equations for spherically and pseudospherically geometries using anisotropic matter and linear form of generic function $f(R,T)$. By imposing different conditions on radial and tangential pressures or by adopting some known choices for red shift and shape functions, we present the graphical analysis of energy conditions for both spherically and pseudospherically symmetric wormholes. It is seen that energy density for spherically symmetric wormhole is always positive for $\lambda>-4\pi$ and $\lambda<-8\pi$, while the energy conditions for radial pressure are negative at throat. Likewise, in case of pseudospherically symmetric wormhole, it is observed that energy density is always positive for negative $\lambda$, however conditions based on radial pressure may be positive or negative for the considered different cases.
|
[
"Physics Archive->gr-qc"
] | 2022-08-09T08:12:30Z |
2310.16915
|
Further evidence for shape coexistence in $^{79}$Zn$^{m}$ near doubly-magic $^{78}$Ni
|
Isomers close to doubly-magic $^{78}_{28}$Ni$_{50}$ provide essential information on the shell evolution and shape coexistence near the ${Z=28}$ and ${N=50}$ double shell closure. We report the excitation energy measurement of the $1/2^{+}$ isomer in $^{79}_{30}$Zn$_{49}$ through independent high-precision mass measurements with the JYFLTRAP double Penning trap and with the ISOLTRAP Multi-Reflection Time-of-Flight Mass Spectrometer. We unambiguously place the $1/2^{+}$ isomer at 942(10) keV, slightly below the $5/2^+$ state at 983(3) keV. With the use of state-of-the-art shell-model diagonalizations, complemented with Discrete Non Orthogonal shell-model calculations which are used here the first time to interpret shape coexistence, we find low-lying deformed intruder states, similar to other ${N=49}$ isotones. The $1/2^{+}$ isomer is interpreted as the band-head of a low-lying deformed structure akin to a predicted low-lying deformed band in $^{80}$Zn, and points to shape coexistence in $^{79,80}$Zn similar to the one observed in $^{78}$Ni. The results make a strong case for confirming the claim of shape coexistence in this key region of the nuclear chart.
|
[
"Physics Archive->nucl->nucl-ex",
"Physics Archive->nucl->nucl-th"
] | 2023-10-25T18:29:22Z |
2304.08136
|
A new second order Taylor-like theorem with an optimized reduced remainder
|
In this paper, we derive a variant of the Taylor theorem to obtain a new minimized remainder. For a given function $f$ defined on the interval $[a,b]$, this formula is derived by introducing a linear combination of $f'$ computed at $n+1$ equally spaced points in $[a,b]$, together with $f''(a)$ and $f''(b)$. We then consider two classical applications of this Taylor-like expansion: the interpolation error and the numerical quadrature formula. We show that using this approach improves both the Lagrange $P_2$ - interpolation error estimate and the error bound of the Simpson rule in numerical integration.
|
[
"Computer Science Archive->cs.NA",
"Mathematics Archive->math.NA"
] | 2023-04-17T10:40:42Z |
1701.02017
|
Neutrino pair annihilation above merger remnants: implications of a long-lived massive neutron star
|
Binary neutron star mergers are plausible progenitor candidates for short gamma-ray bursts (GRBs); however, a detailed explanation of their central engine is still lacking. The annihilation of neutrino pairs has been proposed as one of the possible powering mechanisms. We present calculations of the energy and momentum deposition operated by neutrino pair annihilation above merger remnants. Starting from the results of a detailed, three-dimensional simulation of the aftermath of a binary neutron star merger, we compute the deposition rates over a time scale comparable to the life time of the disk ($t \approx 0.4$ s), assuming a long-lived massive neutron star (MNS). We model neutrino emission using a spectral leakage scheme and compute the neutrino annihilation rates using a ray-tracing algorithm. We find that the presence of the MNS increases the energy deposition rate by a factor $\sim 2$, mainly due to the annihilation of radiation coming from the MNS with radiation coming from the disk. We compute the impact of relativistic effects and discover that, despite they can significantly change the local rate intensity, the volume-integrated results are only marginally decreased. The cumulative deposited energy, extrapolated to 1 sec, is $\approx 2.2 \times 10^{49} \, {\rm erg}$. A comparison with the inferred short GRB energetics reveals that in most cases this energy is not large enough, even assuming small jet opening angles and a long-lived MNS. Significantly more intense neutrino luminosities (a factor ~5-10 larger) are required to explain most of the observed short GRB. We conclude that it is unlikely that neutrino pair annihilation can explain the central engine of short GRBs alone.
|
[
"Physics Archive->astro-ph->astro-ph.HE"
] | 2017-01-08T21:21:14Z |
hep-ph/9512339
|
Is the standard Higgs scalar elementary?
|
In the standard electroweak model, the measured top quark mass requires a sizeable Yukawa coupling to the fundamental scalar. This large coupling alone might induce a dynamical breaking of the electroweak symmetry as well as non-perturbative effects. If such is the case, even a standard Higgs scalar as light as 80 GeV should have a non-negligible $t \bar{t}$ component induced by the top condensate.
|
[
"Physics Archive->hep->hep-ph"
] | 1995-12-18T14:52:44Z |
2302.08412
|
Steric engineering of point defects in lead halide perovskites
|
Due to their high photovoltaic efficiency and low-cost synthesis, lead halide perovskites have attracted wide interest for application in new solar cell technologies. The most stable and efficient ABX$_3$ perovskite solar cells employ mixed A-site cations, however the impact of cation mixing on carrier trapping and recombination -- key processes that limit photovoltaic performance -- is not fully understood. Here we analyse non-radiative carrier trapping in the mixed A-cation hybrid halide perovskite MA$_{1-x}$Cs$_x$PbI$_3$. By using rigorous first-principles simulations we show that cation mixing leads to a hole trapping rate at the iodine interstitial that is eight orders of magnitude greater than in the single cation system. We demonstrate that the same defect in the same material can display a wide variety of defect activity -- from electrically inactive to recombination centre -- and, in doing so, resolve conflicting reports in the literature. Finally, we propose a new mechanism in which steric effects can be used to determine the rate of carrier trapping; this is achieved by controlling the phase and dynamical response of the lattice through the A-site composition. Our findings elucidate crucial links between chemical composition, defect activity and optoelectronic performance, and suggest a general approach that can help to rationalise the development of new crystalline materials with target defect properties.
|
[
"Physics Archive->cond-mat->cond-mat.mtrl-sci"
] | 2023-02-16T16:39:27Z |
1205.6850
|
On the scalar graviton in n-DBI gravity
|
n-DBI gravity is a gravitational theory which yields near de Sitter inflation spontaneously at the cost of breaking Lorentz invariance by a preferred choice of foliation. We show that this breakdown endows n-DBI gravity with one extra physical gravitational degree of freedom: a scalar graviton. Its existence is established by Dirac's theory of constrained systems. Firstly, studying scalar perturbations around Minkowski space-time, we show that there exists one scalar degree of freedom and identify it in terms of the metric perturbations. Then, a general analysis is made in the canonical formalism, using ADM variables. It is useful to introduce an auxiliary scalar field, which allows recasting n-DBI gravity in an Einstein-Hilbert form but in a Jordan frame. Identifying the constraints and their classes we confirm the existence of an extra degree of freedom in the full theory, besides the two usual tensorial modes of the graviton. We then argue that, unlike the case of (the original proposal for) Horava-Lifschitz gravity, there is no evidence that the extra degree of freedom originates pathologies, such as vanishing lapse, instabilities and strong self-coupling at low energy scales.
|
[
"Physics Archive->astro-ph->astro-ph.CO",
"Physics Archive->gr-qc",
"Physics Archive->hep->hep-th"
] | 2012-05-30T22:27:18Z |
gr-qc/0310076
|
Holonomy groups and spacetimes
|
A study is made of the possible holonomy group types of a space-time for which the energy-momentum tensor corresponds to a null or non-null electromagnetic field, a perfect fluid or a massive scalar field. The case of an Einstein space is also included. The techniques developed are also applied to vacuum and conformally flat space-times and contrasted with already known results in these two cases. Examples are given.
|
[
"Physics Archive->gr-qc"
] | 2003-10-15T09:21:05Z |
2104.08957
|
Quantum Filter Diagonalization with Double-Factorized Hamiltonians
|
We demonstrate a method that merges the quantum filter diagonalization (QFD) approach for hybrid quantum/classical solution of the time-independent electronic Schr\"odinger equation with a low-rank double factorization (DF) approach for the representation of the electronic Hamiltonian. In particular, we explore the use of sparse "compressed" double factorization (C-DF) truncation of the Hamiltonian within the time-propagation elements of QFD, while retaining a similarly compressed but numerically converged double-factorized representation of the Hamiltonian for the operator expectation values needed in the QFD quantum matrix elements. Together with significant circuit reduction optimizations and number-preserving post-selection/echo-sequencing error mitigation strategies, the method is found to provide accurate predictions for low-lying eigenspectra in a number of representative molecular systems, while requiring reasonably short circuit depths and modest measurement costs. The method is demonstrated by experiments on noise-free simulators, decoherence- and shot-noise including simulators, and real quantum hardware.
|
[
"Physics Archive->quant-ph"
] | 2021-04-18T21:06:58Z |
2008.07656
|
Information-Theoretic Privacy in Federated Submodel learning
|
We consider information-theoretic privacy in federated submodel learning, where a global server has multiple submodels. Compared to the privacy considered in the conventional federated submodel learning where secure aggregation is adopted for ensuring privacy, information-theoretic privacy provides the stronger protection on submodel selection by the local machine. We propose an achievable scheme that partially adopts the conventional private information retrieval (PIR) scheme that achieves the minimum amount of download. With respect to computation and communication overhead, we compare the achievable scheme with a naive approach for federated submodel learning with information-theoretic privacy.
|
[
"Computer Science Archive->cs.IT",
"Mathematics Archive->math.IT"
] | 2020-08-17T22:44:21Z |
1401.4597
|
Dr.Fill: Crosswords and an Implemented Solver for Singly Weighted CSPs
|
We describe Dr.Fill, a program that solves American-style crossword puzzles. From a technical perspective, Dr.Fill works by converting crosswords to weighted CSPs, and then using a variety of novel techniques to find a solution. These techniques include generally applicable heuristics for variable and value selection, a variant of limited discrepancy search, and postprocessing and partitioning ideas. Branch and bound is not used, as it was incompatible with postprocessing and was determined experimentally to be of little practical value. Dr.Fillls performance on crosswords from the American Crossword Puzzle Tournament suggests that it ranks among the top fifty or so crossword solvers in the world.
|
[
"Computer Science Archive->cs.AI"
] | 2014-01-18T21:05:30Z |
2107.04362
|
RGB Stream Is Enough for Temporal Action Detection
|
State-of-the-art temporal action detectors to date are based on two-stream input including RGB frames and optical flow. Although combining RGB frames and optical flow boosts performance significantly, optical flow is a hand-designed representation which not only requires heavy computation, but also makes it methodologically unsatisfactory that two-stream methods are often not learned end-to-end jointly with the flow. In this paper, we argue that optical flow is dispensable in high-accuracy temporal action detection and image level data augmentation (ILDA) is the key solution to avoid performance degradation when optical flow is removed. To evaluate the effectiveness of ILDA, we design a simple yet efficient one-stage temporal action detector based on single RGB stream named DaoTAD. Our results show that when trained with ILDA, DaoTAD has comparable accuracy with all existing state-of-the-art two-stream detectors while surpassing the inference speed of previous methods by a large margin and the inference speed is astounding 6668 fps on GeForce GTX 1080 Ti. Code is available at \url{https://github.com/Media-Smart/vedatad}.
|
[
"Computer Science Archive->cs.AI",
"Computer Science Archive->cs.CV"
] | 2021-07-09T11:10:11Z |
1904.03041
|
Automatic detection of lesion load change in Multiple Sclerosis using convolutional neural networks with segmentation confidence
|
The detection of new or enlarged white-matter lesions in multiple sclerosis is a vital task in the monitoring of patients undergoing disease-modifying treatment for multiple sclerosis. However, the definition of 'new or enlarged' is not fixed, and it is known that lesion-counting is highly subjective, with high degree of inter- and intra-rater variability. Automated methods for lesion quantification hold the potential to make the detection of new and enlarged lesions consistent and repeatable. However, the majority of lesion segmentation algorithms are not evaluated for their ability to separate progressive from stable patients, despite this being a pressing clinical use-case. In this paper we show that change in volumetric measurements of lesion load alone is not a good method for performing this separation, even for highly performing segmentation methods. Instead, we propose a method for identifying lesion changes of high certainty, and establish on a dataset of longitudinal multiple sclerosis cases that this method is able to separate progressive from stable timepoints with a very high level of discrimination (AUC = 0.99), while changes in lesion volume are much less able to perform this separation (AUC = 0.71). Validation of the method on a second external dataset confirms that the method is able to generalize beyond the setting in which it was trained, achieving an accuracy of 83% in separating stable and progressive timepoints. Both lesion volume and count have previously been shown to be strong predictors of disease course across a population. However, we demonstrate that for individual patients, changes in these measures are not an adequate means of establishing no evidence of disease activity. Meanwhile, directly detecting tissue which changes, with high confidence, from non-lesion to lesion is a feasible methodology for identifying radiologically active patients.
|
[
"Computer Science Archive->cs.CV"
] | 2019-04-05T12:59:58Z |
math/0407078
|
The q-binomial formula and the Rogers dilogarithm identity
|
The q-binomial formula in the limit q->1 is shown to be equivalent to the Rogers five term dilogarithm identity.
|
[
"Mathematics Archive->math.QA"
] | 2004-07-06T13:02:42Z |
hep-ph/0212256
|
Eta, eta-prime photoproduction and electroproduction off nucleons
|
The photo- and electroproduction of eta, eta-prime mesons on nucleons are investigated within a relativistic chiral unitary approach based on coupled channels. The s-wave potentials for electroproduction and meson-baryon scattering are derived from a chiral effective Lagrangian which includes the eta-prime as an explicit degree of freedom and incorporates important features of the underlying QCD Lagrangian such as the axial U(1) anomaly. The effective potentials are iterated in a Bethe-Salpeter equation and cross sections for eta, eta-prime photo- and electroproduction from nucleons are obtained. The results for the eta-prime photoproduction cross section on protons reproduce the appearance of an S_{11} resonance around 1.9 GeV observed at ELSA. The inclusion of electromagnetic form factors increases the predicted eta electroproduction cross sections on the proton, providing a qualitative explanation for the hard form factor of the photocoupling amplitude observed at CLAS.
|
[
"Physics Archive->hep->hep-ph",
"Physics Archive->nucl->nucl-th"
] | 2002-12-17T21:16:07Z |
1812.10039
|
Andrews-Gordon Type Series for Schur's Partition Identity
|
We construct an evidently positive multiple series as a generating function for partitions satisfying the multiplicity condition in Schur's partition theorem. Refinements of the series when parts in the said partitions are classified according to their parities or values mod 3 are also considered. Direct combinatorial interpretations of the series are provided.
|
[
"Mathematics Archive->math.CO"
] | 2018-12-25T05:42:53Z |
0708.0415
|
Search for Pentaquarks in the Hadronic Decays of the Z Boson with the DELPHI Detector at LEP
|
The quark model does not exclude states composed of more than three quarks, like pentaquark systems. Controversial evidence for such states has been published in the last years, in particular: for a strange pentaquark Theta(1540)+; for a double-strange state, the Xi(1862)--, subsequently called Phi(1860)--; and for a charmed state, the Theta_c(3100)^0. If confirmed, a full pentaquark family might exist; such pentaquark states could be produced in e+e- annihilations near the Z energy. In this paper a search for pentaquarks is described using the DELPHI detector at LEP, characterized by powerful particle identification sub-systems crucial in the separation of the signal from the background for these states. At 95% CL, upper limits are set on the production rates <N> of such particles and their charge-conjugate state per Z decay: <N_Theta+> x Br(Theta+ -> pK0_S) < 5.1 x 10^{-4} <N_Theta++> < 1.6 x 10^{-3} <N_Phi(1860)-- > x Br(Phi(1860)-- -> Xi- pi-) < 2.9 x 10^{-4} <Theta_c(3100)^0> x Br(Theta_c(3100)^0 -> D*+ pbar) < 8.8 x 10^{-4} .
|
[
"Physics Archive->hep->hep-ex"
] | 2007-08-02T20:18:57Z |
astro-ph/9807100
|
Oscillation Effects On Neutrinos From The Early Phase Of a Nearby Supernova
|
Neutrinos emitted during stellar core collapse leading to a supernova are primarily of the electron neutrino type at source which may undergo oscillation between flavor eigenstates during propagation to an earth-bound detector. Although the number of neutrinos emitted during the pre-bounce collapse phase is much smaller than that emitted in the post-bounce phase (in which all flavors of neutrinos are emitted), a nearby supernova event may nevertheless register a substantial number of detections from the pre-bounce phase at SuperKamiokande (SK) and the Sudbury Neutrino Observatory (SNO). The calorimetric measurement of the supernova neutrino fluence from this stage via the charge current and neutral current detection channels in SNO and the corresponding distortion of detected spectrum in SK over the no-oscillation spectrum, can probe information about neutrino mass difference and mixing which are illustrated here in terms of two- and three-flavor oscillation models.
|
[
"Physics Archive->astro-ph",
"Physics Archive->hep->hep-ph"
] | 1998-07-10T08:55:15Z |
1701.01048
|
Stochastic Planning and Lifted Inference
|
Lifted probabilistic inference (Poole, 2003) and symbolic dynamic programming for lifted stochastic planning (Boutilier et al, 2001) were introduced around the same time as algorithmic efforts to use abstraction in stochastic systems. Over the years, these ideas evolved into two distinct lines of research, each supported by a rich literature. Lifted probabilistic inference focused on efficient arithmetic operations on template-based graphical models under a finite domain assumption while symbolic dynamic programming focused on supporting sequential decision-making in rich quantified logical action models and on open domain reasoning. Given their common motivation but different focal points, both lines of research have yielded highly complementary innovations. In this chapter, we aim to help close the gap between these two research areas by providing an overview of lifted stochastic planning from the perspective of probabilistic inference, showing strong connections to other chapters in this book. This also allows us to define Generalized Lifted Inference as a paradigm that unifies these areas and elucidates open problems for future research that can benefit both lifted inference and stochastic planning.
|
[
"Computer Science Archive->cs.AI"
] | 2017-01-04T15:37:29Z |
0903.4624
|
On a variant of Hardy inequality between weighted Orlicz spaces
|
Let M be an N-function satisfying the $\Delta_2$- condition, let $\omega, \vp$ be two other functions, $\omega\ge 0$. We study Hardy-type inequalities \[ \int_{\rp} M(\omega (x)|u(x)|) {\rm exp}(-\vp (x))dx \le C\int_{\rp} M(|u'(x)|) {\rm exp}(-\vp (x))dx, \] where $u$ belongs to some dilation invariant set ${\cal R}$ contained in the space of locally absolutely continuous functions. We give sufficient conditions the triple $(\omega,\vp,M)$ must satisfy in order to have such inequalities valid for $u$ from a given set ${\cal R}$. The set ${\cal R}$ can be smaller than the set of Hardy transforms. Bounds for constants, retrieving classical Hardy inequalities with best constants, are also given.
|
[
"Mathematics Archive->math.AP"
] | 2009-03-26T16:27:46Z |
2304.04737
|
A Comparison of Outflow Properties in AGN Dwarfs vs. Star Forming Dwarfs
|
Feedback likely plays a crucial role in resolving discrepancies between observed and theoretical predictions of dwarf galaxy properties. Stellar feedback was once believed to be sufficient to explain these discrepancies, but it has thus far failed to fully reconcile theory and observations. The recent discovery of energetic galaxy-wide outflows in dwarf galaxies hosting Active Galactic Nuclei (AGN) suggests that AGN feedback may have a larger role in the evolution of dwarf galaxies than previously suspected. In order to assess the relative importance of stellar versus AGN feedback in these galaxies, we perform a detailed Keck/KCWI optical integral field spectroscopic study of a sample of low-redshift star-forming (SF) dwarf galaxies that show outflows in ionized gas in their SDSS spectra. We characterize the outflows and compare them to observations of AGN-driven outflows in dwarfs. We find that SF dwarfs have outflow components that have comparable widths (W$_{80}$) to those of outflows in AGN dwarfs, but are much less blue-shifted, indicating that SF dwarfs have significantly slower outflows than their AGN counterparts. The outflows in SF dwarfs are spatially resolved and significantly more extended than those in AGN dwarfs. The mass loss rates, momentum and energy rates of SF-driven outflows are much lower than those of AGN-driven outflows. Our results indicate that AGN feedback in the form of gas outflows may play an important role in dwarf galaxies and should be considered along with SF feedback in models of dwarf galaxy evolution.
|
[
"Physics Archive->astro-ph->astro-ph.GA"
] | 2023-04-10T17:47:44Z |
hep-ph/9612372
|
Heavy Flavor Production and Decay
|
Recent theoretical results on heavy flavor production and decay in the framework of perturbative QCD are reviewed. This includes calculations for top production at hadron colliders, inclusive charmonium production and the comparison between the singlet and octet mechanisms. Predictions for heavy flavor production in $e^+e^-$ annihilation will be discussed in some detail, covering both the threshold and the high energy region. The first results in NLO for heavy flavor decays will also be reviewed.
|
[
"Physics Archive->hep->hep-ph"
] | 1996-12-16T14:17:12Z |
cond-mat/0101358
|
Reaction-diffusion system with self-organized critical behavior
|
We describe the construction of a conserved reaction-diffusion system that exhibits self-organized critical (avalanche-like) behavior under the action of a slow addition of particles. The model provides an illustration of the general mechanism to generate self-organized criticality in conserving systems. Extensive simulations in d=2 and 3 reveal critical exponents compatible with the universality class of the stochastic Manna sandpile model.
|
[
"Physics Archive->cond-mat->cond-mat.stat-mech"
] | 2001-01-23T17:07:56Z |
1104.1525
|
Quantum correlation in three-qubit Heisenberg model with Dzyaloshinskii-Moriya interaction
|
We investigate the pairwise thermal quantum discord in a three-qubit XXZ model with Dzyaloshinskii-Moriya (DM) interaction. We find that the DM interaction can increase quantum discord to a fixed value in the anti- ferromagnetic system, but decreases quantum discord to a minimum first, then increases it to a fixed value in the ferromagnetic system. Abrupt change of quantum discord is observed, which indicates the abrupt change of groundstate. Dynamics of pairwise thermal quantum discord is also considered. We show that thermal discord vanishes in asymptotic limit regardless of its initial values, while thermal entanglement suddenly disappears at finite time.
|
[
"Physics Archive->quant-ph"
] | 2011-04-08T09:01:54Z |
astro-ph/0509430
|
Molecular Superbubbles in the Starburst Galaxy NGC 253
|
The central 2x1 kpc of the starburst galaxy NGC 253 has been imaged using the Submillimeter Array at a 60 pc resolution in the J=2-1 transitions of 12CO, 13CO, and C18O as well as in the 1.3 mm continuum. Molecular gas and dust are mainly in the circumnuclear disk of ~500 pc radius, with warm (~40 K) and high area-filling factor gas in its central part. Two gas shells or cavities have been discovered in the circumnuclear disk. They have ~100 pc diameters and have large velocity widths of 80-100 km/s, suggestive of expansion at ~50 km/s. Modeled as an expanding bubble, each shell has an age of ~0.5 Myr and needed kinetic energy of ~1E46 J as well as mean mechanical luminosity of ~1E33 W for its formation. The large energy allows each to be called a superbubble. A ~10^6 Msun super star cluster can provide the luminosity, and could be a building block of the nuclear starburst in NGC 253. Alternatively, a hypernova can also be the main source of energy for each superbubble, not only because it can provide the mechanical energy and luminosity but also because the estimated rate of superbubble formation and that of hypernova explosions are comparable. Our observations indicate that the circumnuclear molecular disk harboring the starburst is highly disturbed on 100 pc or smaller scales, presumably by individual young clusters and stellar explosions, in addition to globally disturbed in the form of the well-known superwind.
|
[
"Physics Archive->astro-ph"
] | 2005-09-15T10:43:54Z |
1711.08706
|
The limit of Kerr-de Sitter spacetime with infinite angular-momentum parameter $a$
|
We consider the limit $a\rightarrow \infty$ of the Kerr-de Sitter spacetime. The spacetime is a Petrov type-D solution of the vacuum Einstein field equations with a positive cosmological constant $\Lambda$, vanishing Mars-Simon tensor and conformally flat scri. It possesses an Abelian 2-dimensional group of symmetries whose orbits are spacelike or timelike in different regions, and it includes, as a particular case, de Sitter spacetime. The global structure of the solution is analyzed in detail, with particular attention to its Killing horizons: they are foliated by non-compact marginally trapped surfaces of finite area, and one of them `touches' the curvature singularity, which resembles a null 2-dimensional surface. Outside the region between these horizons there exist trapped surfaces that again are non-compact. The solution contains, apart from $\Lambda$, a unique free parameter which can be related to the angular momentum of the non-singular horizon in a precise way. A maximal extension of the (axis of the) spacetime is explicitly built. We also analyze the structure of scri, whose topology is $\mathbb{R}^3$.
|
[
"Physics Archive->gr-qc"
] | 2017-11-23T14:28:03Z |
2011.14578
|
Where Should We Begin? A Low-Level Exploration of Weight Initialization Impact on Quantized Behaviour of Deep Neural Networks
|
With the proliferation of deep convolutional neural network (CNN) algorithms for mobile processing, limited precision quantization has become an essential tool for CNN efficiency. Consequently, various works have sought to design fixed precision quantization algorithms and quantization-focused optimization techniques that minimize quantization induced performance degradation. However, there is little concrete understanding of how various CNN design decisions/best practices affect quantized inference behaviour. Weight initialization strategies are often associated with solving issues such as vanishing/exploding gradients but an often-overlooked aspect is their impact on the final trained distributions of each layer. We present an in-depth, fine-grained ablation study of the effect of different weights initializations on the final distributions of weights and activations of different CNN architectures. The fine-grained, layerwise analysis enables us to gain deep insights on how initial weights distributions will affect final accuracy and quantized behaviour. To our best knowledge, we are the first to perform such a low-level, in-depth quantitative analysis of weights initialization and its effect on quantized behaviour.
|
[
"Computer Science Archive->cs.CV",
"Computer Science Archive->cs.LG"
] | 2020-11-30T06:54:28Z |
cond-mat/0102047
|
Observation of Magnetic Moments in the Superconducting State of YBa$_2$Cu$_3$O$_{6.6}$
|
Neutron Scattering measurements for YBa$_2$Cu$_3$O$_{6.6}$ have identified small magnetic moments that increase in strength as the temperature is reduced below $T^\ast$ and further increase below $T_c$. An analysis of the data shows the moments are antiferromagnetic between the Cu-O planes with a correlation length of longer than 195 \AA in the $a$-$b$ plane and about 35 \AA along the c-axis. The origin of the moments is unknown, and their properties are discusssed both in terms of Cu spin magnetism and orbital bond currents.
|
[
"Physics Archive->cond-mat->cond-mat.str-el",
"Physics Archive->cond-mat->cond-mat.supr-con"
] | 2001-02-04T19:32:53Z |
2212.14186
|
Properties of $^{208}$Pb predicted from the relativistic equation of state in the full Dirac space
|
Relativistic Brueckner-Hartree-Fock (RBHF) theory in the full Dirac space allows one to determine uniquely the momentum dependence of scalar and vector components of the single-particle potentials. In order to extend this new method from nuclear matter to finite nuclei, as a first step, properties of $^{208}$Pb are explored by using the microscopic equation of state for asymmetric nuclear matter and a liquid droplet model. The neutron and proton density distributions, the binding energies, the neutron and proton radii, and the neutron skin thickness in $^{208}$Pb are calculated. In order to further compare the charge densities predicted from the RBHF theory in the full Dirac space with the experimental charge densities, the differential cross sections and the electric charge form factors in the elastic electron-nucleus scattering are obtained by using the phase-shift analysis method. The results from the RBHF theory are in good agreement with the experimental data. In addition, the uncertainty arising from variations of the surface term parameter $f_0$ in the liquid droplet model is also discussed.
|
[
"Physics Archive->nucl->nucl-th"
] | 2022-12-29T06:19:50Z |
astro-ph/0609438
|
Mountains on Neutron Stars: Accreted vs. Non-Accreted crusts
|
The aim of this paper is to compare the two cases of an isolated neutron star, with a non-accreted crust, and that of an accreting neutron star, with an accreted crust, and try to estimate which one of the two would make a better source of gravitational waves. In order to do this we must evaluate the maximum ``mountain'' that the crust can sustain in these two cases. We first do this using the formalism of Ushomirsky, Cutler and Bildsten (2000) and find that the maximum quadrupole is very similar in the two cases, with the non-accreted crust sustaining a slightly larger mountain. We then develop a perturbation formalism for the problem, that allows us to drop the Cowling approximation and have more control over the boundaries. The use of this formalism confirms that there is not much difference between the two cases, but leads to results approximately one order of magnitude larger than those we obtain with the formalism of Ushomirsky, Cutler and Bildsten (2000).
|
[
"Physics Archive->astro-ph"
] | 2006-09-15T13:58:03Z |
0911.5429
|
Quantum System Identification: Hamiltonian Estimation using Spectral and Bayesian Analysis
|
Identifying the Hamiltonian of a quantum system from experimental data is considered. General limits on the identifiability of model parameters with limited experimental resources are investigated, and a specific Bayesian estimation procedure is proposed and evaluated for a model system where a-priori information about the Hamiltonian's structure is available.
|
[
"Physics Archive->quant-ph"
] | 2009-11-28T21:57:47Z |
1105.4535
|
Determination of stellar parameters of C-rich hydrostatic stars from spectro-interferometric observations
|
Giant stars, and especially C-rich giants, contribute significantly to the chemical enrichment of galaxies. The determination of precise parameters for these stars is a necessary prerequisite for a proper implementation of this evolutionary phase in the models of galaxies. Infrared interferometry opened new horizons in the study of the stellar parameters of giant stars, and provided new important constraints for the atmospheric and evolutionary models.We aim to determine which stellar parameters can be constrained by using infrared interferometry and spectroscopy, in the case of C-stars what is the precision which can be achieved and what are the limitations. For this purpose we obtained new infrared spectra and combined them with unpublished interferometric measurements for five mildly variable carbon-rich asymptotic giant branch stars. The observations were compared with a large grid of hydrostatic model atmospheres and with new isochrones which include the predictions of the thermally pulsing phase. For the very first time we are able to reproduce spectra in the range between 0.9 and 4 $\mu$m, and $K$ broad band interferometry with hydrostatic model atmospheres. Temperature, mass, log$(g)$, C/O and a reasonable range for the distance were derived for all the objects of our study. All our targets have at least one combination of best-fitting parameters which lays in the region of the HR-diagram where C-stars are predicted. We confirm that low resolution spectroscopy is not sensitive to the mass and log$(g)$ determination. For hydrostatic objects the $3\,\mu$m feature is very sensitive to temperature variations therefore it is a very powerful tool for accurate temperature determinations. Interferometry can constrain mass, radius and log$(g)$ but a distance has to be assumed. The large uncertainty in the distance measurements available for C-rich stars remains a major problem.
|
[
"Physics Archive->astro-ph->astro-ph.SR"
] | 2011-05-23T15:37:10Z |
1411.2551
|
Indestructibility properties of remarkable cardinals
|
Remarkable cardinals were introduced by Schindler, who showed that the existence of a remarkable cardinal is equiconsistent with the assertion that the theory of $L(\mathbb R)$ is absolute for proper forcing. Here, we study the indestructibility properties of remarkable cardinals. We show that if $\kappa$ is remarkable, then there is a forcing extension in which the remarkability of $\kappa$ becomes indestructible by all $\lt\kappa$-closed $\leq\kappa$-distributive forcing and all two-step iterations of the form ${\rm Add}(\kappa,\theta)*\dot{\mathbb R}$, where $\dot{\mathbb R}$ is forced to be $\lt\kappa$-closed and $\leq\kappa$-distributive. In the process, we introduce the notion of a remarkable Laver function and show that every remarkable cardinal carries such a function. We also show that remarkability is preserved by the canonical forcing of the ${\rm GCH}$.
|
[
"Mathematics Archive->math.LO"
] | 2014-11-10T19:27:07Z |
1805.11244
|
On a sufficient condition for a Fano manifold to be covered by rational $N$-folds
|
In this paper, we prove a conjecture by T. Suzuki, which says if a smooth Fano manifold satisfies some positivity condition on its Chern character, then it can be covered by rational $N$-folds. We prove this conjecture by using purely combinatorial properties of Bernoulli numbers.
|
[
"Mathematics Archive->math.AG",
"Mathematics Archive->math.CO"
] | 2018-05-29T04:53:23Z |
1810.11167
|
Linear Convergence of Cyclic SAGA
|
In this work, we present and analyze C-SAGA, a (deterministic) cyclic variant of SAGA. C-SAGA is an incremental gradient method that minimizes a sum of differentiable convex functions by cyclically accessing their gradients. Even though the theory of stochastic algorithms is more mature than that of cyclic counterparts in general, practitioners often prefer cyclic algorithms. We prove C-SAGA converges linearly under the standard assumptions. Then, we compare the rate of convergence with the full gradient method, (stochastic) SAGA, and incremental aggregated gradient (IAG), theoretically and experimentally.
|
[
"Mathematics Archive->math.OC"
] | 2018-10-26T02:17:52Z |
2108.04958
|
Physics-inspired architecture for neural network modeling of forces and torques in particle-laden flows
|
We present a physics-inspired neural network (PINN) model for direct prediction of hydrodynamic forces and torques experienced by individual particles in stationary beds of randomly distributed spheres. In line with our findings, it has recently been demonstrated that conventional fully connected neural networks (FCNN) are incapable of making accurate predictions of force variations in a static bed of spheres. The problem arises due to the large number of input variables (i.e., the locations of individual neighboring particles) leading to an overwhelmingly large number of training parameters in a fully connected architecture. Given the typically limited size of training datasets that can be generated by particle-resolved simulations, the NN becomes prone to missing true patterns in the data, ultimately leading to overfitting. Inspired by our observations in developing the microstructure-informed probability-driven point-particle (MPP) model, we incorporate two main features in the architecture of the present PINN model: 1) superposition of pairwise hydrodynamic interactions between particles, and 2) sharing training parameters between NN blocks that model neighbor influences. These strategies helps to substantially reduce the number of free parameters and thereby control the model complexity without compromising accuracy. We demonstrate that direct force and torque prediction using NNs is indeed possible, provided that the model structure corresponds to the underlying physics of the problem. For a Reynolds number range of 2 <= Re <= 150 and solid volume fractions of 0.1 <= phi <= 0.4, the PINN's predictions prove to be as accurate as those of other microstructure-informed models.
|
[
"Physics Archive->physics->physics.comp-ph",
"Physics Archive->physics->physics.flu-dyn"
] | 2021-08-10T23:08:39Z |
1607.08196
|
Calorie Counter: RGB-Depth Visual Estimation of Energy Expenditure at Home
|
We present a new framework for vision-based estimation of calorific expenditure from RGB-D data - the first that is validated on physical gas exchange measurements and applied to daily living scenarios. Deriving a person's energy expenditure from sensors is an important tool in tracking physical activity levels for health and lifestyle monitoring. Most existing methods use metabolic lookup tables (METs) for a manual estimate or systems with inertial sensors which ultimately require users to wear devices. In contrast, the proposed pose-invariant and individual-independent vision framework allows for a remote estimation of calorific expenditure. We introduce, and evaluate our approach on, a new dataset called SPHERE-calorie, for which visual estimates can be compared against simultaneously obtained, indirect calorimetry measures based on gas exchange. % based on per breath gas exchange. We conclude from our experiments that the proposed vision pipeline is suitable for home monitoring in a controlled environment, with calorific expenditure estimates above accuracy levels of commonly used manual estimations via METs. With the dataset released, our work establishes a baseline for future research for this little-explored area of computer vision.
|
[
"Computer Science Archive->cs.CV"
] | 2016-07-27T17:47:44Z |
2212.11595
|
Metadata-guided Consistency Learning for High Content Images
|
High content imaging assays can capture rich phenotypic response data for large sets of compound treatments, aiding in the characterization and discovery of novel drugs. However, extracting representative features from high content images that can capture subtle nuances in phenotypes remains challenging. The lack of high-quality labels makes it difficult to achieve satisfactory results with supervised deep learning. Self-Supervised learning methods have shown great success on natural images, and offer an attractive alternative also to microscopy images. However, we find that self-supervised learning techniques underperform on high content imaging assays. One challenge is the undesirable domain shifts present in the data known as batch effects, which are caused by biological noise or uncontrolled experimental conditions. To this end, we introduce Cross-Domain Consistency Learning (CDCL), a self-supervised approach that is able to learn in the presence of batch effects. CDCL enforces the learning of biological similarities while disregarding undesirable batch-specific signals, leading to more useful and versatile representations. These features are organised according to their morphological changes and are more useful for downstream tasks -- such as distinguishing treatments and mechanism of action.
|
[
"Computer Science Archive->cs.CV"
] | 2022-12-22T10:39:10Z |
2107.06039
|
AutoScore-Imbalance: An interpretable machine learning tool for development of clinical scores with rare events data
|
Background: Medical decision-making impacts both individual and public health. Clinical scores are commonly used among a wide variety of decision-making models for determining the degree of disease deterioration at the bedside. AutoScore was proposed as a useful clinical score generator based on machine learning and a generalized linear model. Its current framework, however, still leaves room for improvement when addressing unbalanced data of rare events. Methods: Using machine intelligence approaches, we developed AutoScore-Imbalance, which comprises three components: training dataset optimization, sample weight optimization, and adjusted AutoScore. All scoring models were evaluated on the basis of their area under the curve (AUC) in the receiver operating characteristic analysis and balanced accuracy (i.e., mean value of sensitivity and specificity). By utilizing a publicly accessible dataset from Beth Israel Deaconess Medical Center, we assessed the proposed model and baseline approaches in the prediction of inpatient mortality. Results: AutoScore-Imbalance outperformed baselines in terms of AUC and balanced accuracy. The nine-variable AutoScore-Imbalance sub-model achieved the highest AUC of 0.786 (0.732-0.839) while the eleven-variable original AutoScore obtained an AUC of 0.723 (0.663-0.783), and the logistic regression with 21 variables obtained an AUC of 0.743 (0.685-0.800). The AutoScore-Imbalance sub-model (using down-sampling algorithm) yielded an AUC of 0. 0.771 (0.718-0.823) with only five variables, demonstrating a good balance between performance and variable sparsity. Conclusions: The AutoScore-Imbalance tool has the potential to be applied to highly unbalanced datasets to gain further insight into rare medical events and to facilitate real-world clinical decision-making.
|
[
"Computer Science Archive->cs.LG"
] | 2021-07-13T12:49:32Z |
physics/0508222
|
Understanding widely scattered traffic flows, the capacity drop, platoons, and times-to-collision as effects of variance-driven time gaps
|
We investigate the adaptation of the time headways in car-following models as a function of the local velocity variance, which is a measure of the inhomogeneity of traffic flow. We apply this mechanism to several car-following models and simulate traffic breakdowns in open systems with an on-ramp as bottleneck. Single-vehicle data generated by several 'virtual detectors' show a semi-quantitative agreement with microscopic data from the Dutch freeway A9. This includes the observed distributions of the net time headways and times-to-collision for free and congested traffic. While the times-to-collision show a nearly universal distribution in free and congested traffic, the modal value of the time headway distribution is shifted by a factor of about two in congested conditions. Macroscopically, this corresponds to the 'capacity drop' at the transition from free to congested traffic. Finally, we explain the wide scattering of one-minute flow-density data by a self-organized variance-driven process that leads to the spontaneous formation and decay of long-lived platoons even for deterministic dynamics on a single lane.
|
[
"Physics Archive->physics->physics.soc-ph"
] | 2005-08-30T18:55:52Z |
1606.02197
|
Two-qubit correlations revisited: average mutual information, relevant (and useful) observables and an application to remote state preparation
|
Understanding how correlations can be used for quantum communication protocols is a central goal of quantum information science. While many authors have linked global measures of correlations such as entanglement or discord to the performance of specific protocols, in general the latter may require only correlations between specific observables. In this work, we first introduce a general measure of correlations for two-qubit states based on the classical mutual information between local observables. We then discuss the role of the symmetry in the state's correlations distribution and accordingly provide a classification of maximally mixed marginals states (MMMS). We discuss the complementarity relation between correlations and coherence. By focusing on a simple yet paradigmatic example, i.e., the remote state preparation protocol, we introduce a method to systematically define proper protocol-tailored measures of correlations. The method is based on the identification of those correlations that are relevant (useful) for the protocol. The approach allows on one hand to discuss the role of the symmetry of the correlations distribution in determining the efficiency of the protocol, both for MMMS and general two-qubit quantum states, and on the other hand to devise an optimized protocol for non-MMMS that can have a better efficiency with respect to the standard one. The scheme we propose can be extended to other communication protocols and more general bipartite settings. Overall our findings clarify how the key resources in simple communication protocols are the purity of the state used and the symmetry of correlations distribution.
|
[
"Physics Archive->quant-ph"
] | 2016-06-07T16:13:30Z |
0810.1757
|
Scenario for Fractional Quantum Hall Effect in Bulk Isotropic Materials
|
We investigate the possibility of a strongly correlated Fractional Quantum Hall (FQH) state in bulk three dimensional isotropic (not layered) materials. We find that a FQH state can exist at low densities only if it is accompanied by a staging transition in which the electrons re-organize themselves in layers, perpendicular to the magnetic field, at distances of order the magnetic length apart. The Hartree energy associated to the staging transition is off-set by the correlation Fock energy of the 3D FQH state. We obtain the phase diagram of bulk electrons in a magnetic field subject to Coulomb interactions as a function of carrier density and lattice constant. At very low densities, the 3D FQH state exhibits a transition to a 3D Wigner crystal state stabilized by phonon correlations.
|
[
"Physics Archive->cond-mat->cond-mat.mes-hall",
"Physics Archive->cond-mat->cond-mat.str-el"
] | 2008-10-10T19:58:25Z |
2102.00356
|
Measuring association with Wasserstein distances
|
Let $\pi\in \Pi(\mu,\nu)$ be a coupling between two probability measures $\mu$ and $\nu$ on a Polish space. In this article we propose and study a class of nonparametric measures of association between $\mu$ and $\nu$, which we call Wasserstein correlation coefficients. These coefficients are based on the Wasserstein distance between $\nu$ and the disintegration $\pi_{x_1}$ of $\pi$ with respect to the first coordinate. We also establish basic statistical properties of this new class of measures: we develop a statistical theory for strongly consistent estimators and determine their convergence rate in the case of compactly supported measures $\mu$ and $\nu$. Throughout our analysis we make use of the so-called adapted/bicausal Wasserstein distance, in particular we rely on results established in [Backhoff, Bartl, Beiglb\"ock, Wiesel. Estimating processes in adapted Wasserstein distance. 2020]. Our approach applies to probability laws on general Polish spaces.
|
[
"Mathematics Archive->math.PR",
"Mathematics Archive->math.ST",
"Statistics Archive->stat.TH"
] | 2021-01-31T02:28:43Z |
hep-th/9310122
|
Conservation Laws and Geometry of Perturbed Coset Models
|
We present a Lagrangian description of the $SU(2)/U(1)$ coset model perturbed by its first thermal operator. This is the simplest perturbation that changes sign under Krammers--Wannier duality. The resulting theory, which is a 2--component generalization of the sine--Gordon model, is then taken in Minkowski space. For negative values of the coupling constant $g$, it is classically equivalent to the $O(4)$ non--linear $\s$--model reduced in a certain frame. For $g > 0$, it describes the relativistic motion of vortices in a constant external field. Viewing the classical equations of motion as a zero curvature condition, we obtain recursive relations for the infinitely many conservation laws by the abelianization method of gauge connections. The higher spin currents are constructed entirely using an off--critical generalization of the $W_{\infty}$ generators. We give a geometric interpretation to the corresponding charges in terms of embeddings. Applications to the chirally invariant $U(2)$ Gross--Neveu model are also discussed.
|
[
"Physics Archive->hep->hep-th"
] | 1993-10-19T16:18:35Z |
astro-ph/9503036
|
Possible Extragalactic Sources of the Highest Energy Cosmic Rays
|
We give an outline of possible extragalactic explanations of the highest energy cosmic ray events. We give a classification of the possible particles which could have caused the events and try to find suitable sources for each class. In contrast to some previous investigations of other authors, we find a possible candidate of a local FR-II radio galaxy close to the Fly's Eye event, and less powerful active galaxies close to the AGASA event. We also note the interesting coincidence that we have strong, distant quasars inside the arrival direction error regimes of both the Fly's Eye and AGASA event. We briefly discuss the consequences for the cosmic ray spectrum and composition at highest energies, which could be investigated by future experiments.
|
[
"Physics Archive->astro-ph"
] | 1995-03-08T15:03:24Z |
2308.14985
|
Stochastic Motion Planning as Gaussian Variational Inference: Theory and Algorithms
|
We consider the motion planning problem under uncertainty and address it using probabilistic inference. A collision-free motion plan with linear stochastic dynamics is modeled by a posterior distribution. Gaussian variational inference is an optimization over the path distributions to infer this posterior within the scope of Gaussian distributions. We propose Gaussian Variational Inference Motion Planner (GVI-MP) algorithm to solve this Gaussian inference, where a natural gradient paradigm is used to iteratively update the Gaussian distribution, and the factorized structure of the joint distribution is leveraged. We show that the direct optimization over the state distributions in GVI-MP is equivalent to solving a stochastic control that has a closed-form solution. Starting from this observation, we propose our second algorithm, Proximal Gradient Covariance Steering Motion Planner (PGCS-MP), to solve the same inference problem in its stochastic control form with terminal constraints. We use a proximal gradient paradigm to solve the linear stochastic control with nonlinear collision cost, where the nonlinear cost is iteratively approximated using quadratic functions and a closed-form solution can be obtained by solving a linear covariance steering at each iteration. We evaluate the effectiveness and the performance of the proposed approaches through extensive experiments on various robot models. The code for this paper can be found in https://github.com/hzyu17/VIMP.
|
[
"Computer Science Archive->cs.RO"
] | 2023-08-29T02:31:00Z |
hep-th/9209130
|
Free Field Representation for the Classical Limit of Quantum Affine Algebra
|
Free field representation for the classical limit of quantum affine algebra is constructed by simple deformation of the known expressions from WZW theory.
|
[
"Physics Archive->hep->hep-th"
] | 1992-09-30T20:55:39Z |
1708.05608
|
Periodic solutions of integro-differential equations in Banach space having Fourier type
|
The aim of this work is to study the existence of a periodic solutions of integro-differential equations d dt [x(t)-- L(x t)] = A[x(t)-- L(x t)]+ G(x t)+ t --$\infty$ a(t-- s)x(s)ds+ f (t), (0 $\le$ t $\le$ 2$\pi$) with the periodic condition x(0) = x(2$\pi$), where a $\in$ L 1 (R +). Our approach is based on the M-boundedness of linear operators, Fourier type, B s p,q-multipliers and Besov spaces.
|
[
"Mathematics Archive->math.FA"
] | 2017-06-26T14:42:16Z |
1101.2579
|
Effect of interactions on the cellular uptake of nanoparticles
|
We present a simple two-state model to understand the size-dependent endocytosis of nanoparticles. Using this model, we elucidate the relevant energy terms required to understand the size-dependent uptake mechanism and verify it by correctly predicting the behavior at large and small particle sizes. In the absence of interactions between the nanoparticles we observe an asymmetric distribution of sizes with maximum uptake at intermediate sizes and a minimum size cut-off below which there can be no endocytosis. Including the effect of interactions in our model has remarkable effects on the uptake characteristics. Attractive interactions shift the minimum size cut-off and increase the optimal uptake while repulsive interactions make the distribution more symmetric lowering the optimal uptake.
|
[
"Physics Archive->cond-mat->cond-mat.soft",
"Physics Archive->physics->physics.bio-ph"
] | 2011-01-13T15:11:45Z |
2302.03506
|
Dynamic Training of Liquid State Machines
|
Spiking Neural Networks (SNNs) emerged as a promising solution in the field of Artificial Neural Networks (ANNs), attracting the attention of researchers due to their ability to mimic the human brain and process complex information with remarkable speed and accuracy. This research aimed to optimise the training process of Liquid State Machines (LSMs), a recurrent architecture of SNNs, by identifying the most effective weight range to be assigned in SNN to achieve the least difference between desired and actual output. The experimental results showed that by using spike metrics and a range of weights, the desired output and the actual output of spiking neurons could be effectively optimised, leading to improved performance of SNNs. The results were tested and confirmed using three different weight initialisation approaches, with the best results obtained using the Barabasi-Albert random graph method.
|
[
"Computer Science Archive->cs.NE"
] | 2023-02-06T16:07:36Z |
1210.4697
|
A computational approach to the discriminant of homogeneous polynomials
|
In this paper, the discriminant of homogeneous polynomials is studied in two particular cases: a single homogeneous polynomial and a collection of n-1 homogeneous polynomials in n variables. In these two cases, the discriminant is defined over a large class of coefficient rings by means of the resultant. Many formal properties and computational rules are provided and the geometric interpretation of the discriminant is investigated over a general coefficient ring, typically a domain.
|
[
"Mathematics Archive->math.AC",
"Mathematics Archive->math.AG"
] | 2012-10-17T11:19:23Z |
1801.00115
|
Emergent Coulomb forces in reducible Quantum Electrodynamics
|
This paper discusses an attempt to develop a mathematically rigorous theory of Quantum Electrodynamics (QED). It deviates from the standard version of QED mainly in two aspects: it is assumed that the Coulomb forces are carried by transversely polarized photons, and a reducible representation of the canonical commutation and anti-commutation relations is used. Both interventions together should suffice to eliminate the mathematical inconsistencies of standard QED.
|
[
"Mathematics Archive->math.MP",
"Physics Archive->hep->hep-th",
"Physics Archive->math-ph",
"Physics Archive->quant-ph"
] | 2017-12-30T10:59:13Z |
1307.8259
|
For a few elements more: A survey of finite Rees index
|
This paper makes a comprehensive survey of results relating to finite Rees index for semigroups. In particular, we survey of the state of knowledge on whether various finiteness properties (such as finite generation, finite presentability, automaticity, and hopficity) are inherited by finite Rees index subsemigroups and extensions. We survey other properties that are invariant under passing to finite Rees index subsemigroups and extensions, such as the cofinality and number of ends. We prove some new results: inheritance of word-hyperbolicity by finite Rees index subsemigroups, and inheritance of (geometric) hyperbolicity by finite Rees index extensions and subsemigroups within the class of monoids of finite geometric type. We also give some improved counterexamples. All the results are summarized in a table.
|
[
"Mathematics Archive->math.GR"
] | 2013-07-31T09:36:14Z |
hep-ph/0304033
|
Electromagnetic nucleon-delta transition in the perturbative chiral quark model
|
We apply the perturbative chiral quark model to the gamma N -> Delta transition. The four momentum dependence of the respective transverse helicity amplitudes A(1/2) and A(3/2) is determined at one loop in the pseudoscalar Goldstone boson fluctuations. Inclusion of excited states in the quark propagator is shown to result in a reasonable description of the experimental values for the helicity amplitudes at the real photon point.
|
[
"Physics Archive->hep->hep-ph"
] | 2003-04-03T16:22:58Z |
0712.1633
|
Strong lensing probability in TeVeS theory
|
We recalculate the strong lensing probability as a function of the image separation in TeVeS (tensor-vector-scalar) cosmology, which is a relativistic version of MOND (MOdified Newtonian Dynamics). The lens is modeled by the Hernquist profile. We assume an open cosmology with $\Omega_b=0.04$ and $\Omega_\Lambda=0.5$ and three different kinds of interpolating functions. Two different galaxy stellar mass functions (GSMF) are adopted: PHJ (Panter-Heavens-Jimenez, 2004) determined from SDSS data release one and Fontana (Fontana et al., 2006) from GOODS-MUSIC catalog. We compare our results with both the predicted probabilities for lenses by Singular Isothermal Sphere (SIS) galaxy halos in LCDM (lambda cold dark matter) with Schechter-fit velocity function, and the observational results of the well defined combined sample of Cosmic Lens All-Sky Survey (CLASS) and Jodrell Bank/Very Large Array Astrometric Survey (JVAS). It turns out that the interpolating function $\mu(x)=x/(1+x)$ combined with Fontana GSMF matches the results from CLASS/JVAS quite well.
|
[
"Physics Archive->astro-ph"
] | 2007-12-11T02:24:49Z |
astro-ph/0205261
|
On the nature of the compact condensations at the centre of galaxies
|
There are many observational evidences for the existence of massive compact condensations in the range $10^6 -10^{10} M_\odot$ at the core of various galaxies. At present such condensations are commonly interpreted as Black Holes (BHs). However, we point out that while such Black Hole Candidates (BHCs) must be similar to BHs in many respects they, actually, can not be BHs because existence of Black Holes would violate the basic tenet of the General Theory of Relativity (GTR) that the worldline of a material particle must be timelike at any regular region of spacetime. On the other hand general relativistic collapse of very massive bodies should lead to Eternally Collapsing Configurations (ECOs) or Ultra Compact Objects (UCOs). While ECOs/UCOs may practically be as compact as corresponding BHs, they will have a physical surface. Also while BHs do not have any intrinsic magnetic field ECOs may have strong intrinsic magnetic field. We point out that despite many claims actually there is no real evidence for the ``Event Horizon'' (EH) of supposed BHs and on the other hand, there are tentative evidence for the existence of strong magnetic field in several BHCs (or ECOs). The presence of such intrinsic magnetic field may render the task of explaining high energy radiation phenomenon in many Active Galactic Nuclei easier.
|
[
"Physics Archive->astro-ph",
"Physics Archive->gr-qc"
] | 2002-05-16T18:39:39Z |
2309.00209
|
Let's Play Together through Channels: Understanding the Practices and Experience of Danmaku Participation Game Players in China
|
Live streaming is becoming increasingly popular in recent years, as most channels prioritize the delivery of engaging content to their viewers. Among various live streaming channels, Danmaku participation game (DPG) has emerged in China as a mixture of live streaming and online gaming, offering an immersive gaming experience to players. Although prior research has explored audience participation games (APGs) in North America and Europe, it primarily focuses on discussing prototypes and lacks observation of players in natural settings. Little is known about how players perceive DPGs and their player experience. To fill the research gap, we observed a series of DPG channels and conducted an interview-based study to gain insights into the practices and experiences of DPG players. Our work reveals that DPGs can effectively synergize live streaming and online games, amplifying both player engagement and a profound sense of accomplishment to players.
|
[
"Computer Science Archive->cs.HC"
] | 2023-09-01T02:00:06Z |
1406.6423
|
Slow entropy for abelian actions
|
We calculate slow entropy type invariant introduced by A. Katok and J.-P. Thouvenot in [5] for higher rank smooth abelian actions for two leading cases: when the invariant measure is absolutely continuous and when it is hyperbolic. As a by-product, we generalize Brin-Katok local entropy Theorem to the abelian action for the above two cases. We also prove that, for abelian actions, the transversal Hausdorff dimensions are universal, i.e. dependent on the action but not on any individual element of the action.
|
[
"Mathematics Archive->math.DS"
] | 2014-06-25T00:39:55Z |
1710.04897
|
Reducing a cortical network to a Potts model yields storage capacity estimates
|
An autoassociative network of Potts units, coupled via tensor connections, has been proposed and analysed as an effective model of an extensive cortical network with distinct short- and long-range synaptic connections, but it has not been clarified in what sense it can be regarded as an effective model. We draw here the correspondence between the two, which indicates the need to introduce a local feedback term in the reduced model, i.e., in the Potts network. An effective model allows the study of phase transitions. As an example, we study the storage capacity of the Potts network with this additional term, the local feedback $w$, which contributes to drive the activity of the network towards one of the stored patterns. The storage capacity calculation, performed using replica tools, is limited to fully connected networks, for which a Hamiltonian can be defined. To extend the results to the case of intermediate partial connectivity, we also derive the self-consistent signal-to-noise analysis for the Potts network; and finally we discuss implications for semantic memory in humans.
|
[
"Quantitative Biology Archive->q-bio.NC"
] | 2017-10-13T12:54:38Z |
2003.12166
|
A generalization of primitive sets and a conjecture of Erd\H{o}s
|
A set of integers greater than 1 is primitive if no element divides another. Erd\H{o}s proved in 1935 that the sum of $1/(n \log n)$ for $n$ running over a primitive set $A$ is universally bounded over all choices for $A$. In 1988 he asked if this universal bound is attained by the set of prime numbers. We answer the Erd\H{o}s question in the affirmative for 2-primitive sets. Here a set is 2-primitive if no element divides the product of 2 other elements.
|
[
"Mathematics Archive->math.CO",
"Mathematics Archive->math.NT"
] | 2020-03-26T22:00:44Z |
1409.0540
|
The Landscape of the Neutrino Mechanism of Core-Collapse Supernovae: Neutron Star and Black Hole Mass Functions, Explosion Energies and Nickel Yields
|
If the neutrino luminosity from the proto-neutron star formed during a massive star core collapse exceeds a critical threshold, a supernova (SN) results. Using spherical quasi-static evolutionary sequences for hundreds of progenitors over a range of metallicities, we study how the explosion threshold maps onto observables, including the fraction of successful explosions, the neutron star (NS) and black hole (BH) mass functions, the explosion energies (E_SN) and nickel yields (M_Ni), and their mutual correlations. Successful explosions are intertwined with failures in a complex pattern that is not simply related to initial progenitor mass or compactness. We predict that progenitors with initial masses of 15 +/- 1, 19 +/- 1, and 21-26 M_Sun are most likely to form BHs, that the BH formation probability is non-zero at solar-metallicity and increases significantly at low metallicity, and that low luminosity, low Ni-yield SNe come from progenitors close to success/failure interfaces. We qualitatively reproduce the observed E_SN-M_Ni correlation, we predict a correlation between the mean and width of the NS mass and E_SN distributions, and that the means of the NS and BH mass distributions are correlated. We show that the observed mean NS mass of ~1.33 M_Sun implies that the successful explosion fraction is higher than 0.35. Overall, we show that the neutrino mechanism can in principle explain the observed properties of SNe and their compact objects. We argue that the rugged landscape of progenitors and outcomes mandates that SN theory should focus on reproducing the wide ranging distributions of observed SN properties.
|
[
"Physics Archive->astro-ph->astro-ph.HE"
] | 2014-09-01T20:00:23Z |
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