In this paper, we present results on ordered representations of data in which different dimensions have different degrees of importance. To learn these representations we introduce nested dropout, a procedure for stoc...
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ISBN:
(纸本)9781634393973
In this paper, we present results on ordered representations of data in which different dimensions have different degrees of importance. To learn these representations we introduce nested dropout, a procedure for stochastically removing coherent nested sets of hidden units in a neural network. We first present a sequence of theoretical results for the special case of a semi-linear autoencoder. We rigorously show that the application of nested dropout enforces identifiability of the units, which leads to an exact equivalence with PCA. We then extend the algorithm to deep models and demonstrate the relevance of ordered representations to a number of applications. Specifically, we use the ordered property of the learned codes to construct hash-based data structures that permit very fast retrieval, achieving retrieval in time logarithmic in the database size and independent of the dimensionality of the representation. This allows codes that are hundreds of times longer than currently feasible for retrieval. We therefore avoid the diminished quality associated with short codes, while still performing retrieval that is competitive in speed with existing methods. We also show that ordered representations are a promising way to learn adaptive compression for efficient online data reconstruction. Copyright 2014 by the author(s).
Most conceptual and computational models assume that synaptic transmission is reliable, a simplification rarely substantiated by data. The functional consequences of the recruitment of high and low initial release pro...
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Most conceptual and computational models assume that synaptic transmission is reliable, a simplification rarely substantiated by data. The functional consequences of the recruitment of high and low initial release probability synapses on the reliability and precision of their postsynaptic targets are studied in a multi-compartmental model of a hippocampal CA1 pyramidal cell. We show that changes in the firing rate of CA3 afferent inputs (rate remapping) are not reflected in the firing rate of the CA1 cell but in the reliability and precise timing of some of its action potentials, suggesting that a signature of remapping may be found in the precise spike timing of CA1. Our results suggest that about half of the action potentials produced by a CA1 cell can potentially carry reliable information in their precise timing with about 25 ms precision, a time scale on the order of the gamma cycle. We show further that reliable events were primarily elicited by CA3 synapses in a state of low probability of release. Overall, our results suggest that the non-uniform distribution of initial release probabilities observed experimentally achieves an optimum yielding simultaneously high precision and high reliability, and allows large populations of CA3 synapses to contribute to the production of reliable CA1 spiking events.
We explore time-based solvers for linear standing-wave problems, especially the oscillatory Helmholtz equation. Here, we show how to accelerate the convergence properties of timestepping. We introduce a new time-based...
We explore time-based solvers for linear standing-wave problems, especially the oscillatory Helmholtz equation. Here, we show how to accelerate the convergence properties of timestepping. We introduce a new time-based solver that we call phase-adjusted time-averaging (PATA), which we couple to timestepping to form the PATA-TS solver. Numerical experiments indicate that the PATA-TS solver is faster than the PATA solver and timestepping by a factor of 1.2 and 1.5 or more, respectively. We also explain why the PATA-TS solver is robust, efficient, and easy to program for a variety of practical applications.
Displaced phase-amplitude variable in polar form. This variable is used to investigate changes in amplitude in complex fields with phases that depend only on the position in the propagation. Soliton on Finite Backgrou...
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The crack of a whip is produced by a shock wave created by the supersonic motion of the tip of the whip in the air. A simple dynamical model for the propagation and acceleration of waves in the motion of whips is pres...
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The crack of a whip is produced by a shock wave created by the supersonic motion of the tip of the whip in the air. A simple dynamical model for the propagation and acceleration of waves in the motion of whips is presented. The respective contributions of tension, tapering, and boundary conditions in the acceleration of an initial impulse are studied theoretically and numerically.
We introduce an inverse problem for the local volatility model in option pricing. We solve the problem using the Levenberg-Marquardt algorithm and use the notion of the Fréchet derivative when calculating the Jac...
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The cruise-dash problem can be viewed as that of minimizing fuel while maintaining a specified average speed. Periodic solutions are shown to exhibit singular throttle behavior. The character of these solutions is exa...
Objective:To investigate the isolation of enterobacteria associated with Macrobrachium amazonicum(***) farming and evaluate the in vitro antimicrobial susceptibility of Vibrio ***:Strains were isolated from female ***...
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Objective:To investigate the isolation of enterobacteria associated with Macrobrachium amazonicum(***) farming and evaluate the in vitro antimicrobial susceptibility of Vibrio ***:Strains were isolated from female *** prawns and environmental and hatchery *** assays were used to identify bacterial genera and those belonging to the genus Vibrio were submitted to further analyses for species identification,through Vitek 2 automated system and *** test was performed according to Clinical Laboratory Standards ***:The following genera of enlerobacteria were recovered:Enterobacter(n=11),Citrobacter(n=10),Proteus(n=2),Serratia(n=2),Kluyvera(n=2),Providencia(n=2),Cedecea(n=1),Escherichia(n=1).Edwardsiella(n=1) and BulliauxeUa(n=1).As for Vibrio,three species were identified:Vibrio cholerae non-O1/non-O139(n=4).Vibrio vulnificus(***)(n=1) and Vibrio mimicus(n=1).Vibrio *** minimum inhibitory concentrations values within the susceptibility range established by Clinical Laboratory Standards Institute for almost all antibiotics,except for ***,which presented intermediate profile to ***:Enterobacteria do not seem to be the most important pathogens associated with *** farming,whereas the recovery of Vibrio *** larviculture,with emphasis on Vibrio cholerae and ***,deserves special attention due to their role as potentially zoonotic aquaculture-associated ***,the intermediate susceptibility of *** to ampicillin reflects the importance of monitoring drug use in prawn farming.
Single-particle cryo-electron microscopy (cryo-EM) has recently joined X-ray crystallography and NMR spectroscopy as a high-resolution structural method for biological macromolecules. Cryo-EM was selected by Nature Me...
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The 6th International Conference on Mathematical Modelling and Analysis of Populations in Biology (ICMA-VI) was held at the University of Arizona, Tucson, Arizona USA on 20-22 October 2017. Plenary addresses were give...
The 6th International Conference on Mathematical Modelling and Analysis of Populations in Biology (ICMA-VI) was held at the University of Arizona, Tucson, Arizona USA on 20-22 October 2017. Plenary addresses were given by Henri Berestycki (Centre d'analyse et de mathématique sociales, Paris, France), Regis Ferriere (Ecology and Evolutionary Biology department, University of Arizona, Tucson, Arizona, USA), Rosie Fisher (National Center for Atmospheric Research Climate & Global Dynamics, Boulder, Colorado, USA), and Mercedes Pascual (department of Ecology and Evolution, University of Chicago, Chicago, Illinois, USA). The conference received support from the department of mathematics, University of Arizona; the department of Ecology and Evolutionary Biology, University of Arizona; the interdisciplinaryprogram in appliedmathematics, University of Arizona; and the Simon A. Levin Mathematical, Computational and Modeling Sciences Center, Arizona State University. [Extracted from the article]
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