5,037 research outputs found

    A self-learning rule base for command following in dynamical systems

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    In this paper, a self-learning Rule Base for command following in dynamical systems is presented. The learning is accomplished though reinforcement learning using an associative memory called SAM. The main advantage of SAM is that it is a function approximator with explicit storage of training samples. A learning algorithm patterned after the dynamic programming is proposed. Two artificially created, unstable dynamical systems are used for testing, and the Rule Base was used to generate a feedback control to improve the command following ability of the otherwise uncontrolled systems. The numerical results are very encouraging. The controlled systems exhibit a more stable behavior and a better capability to follow reference commands. The rules resulting from the reinforcement learning are explicitly stored and they can be modified or augmented by human experts. Due to overlapping storage scheme of SAM, the stored rules are similar to fuzzy rules

    Charmed Baryon Weak Decays with SU(3) Flavor Symmetry

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    We study the semileptonic and non-leptonic charmed baryon decays with SU(3)SU(3) flavor symmetry, where the charmed baryons can be Bc=(Ξc0,Ξc+,Λc+){\bf B}_{c}=(\Xi_c^0,\Xi_c^+,\Lambda_c^+), Bc=(Σc(++,+,0),Ξc(+,0),Ωc0){\bf B}'_{c}=(\Sigma_c^{(++,+,0)},\Xi_{c}^{\prime(+,0)},\Omega_c^0), Bcc=(Ξcc++,Ξcc+,Ωcc+){\bf B}_{cc}=(\Xi_{cc}^{++},\Xi_{cc}^+,\Omega_{cc}^+), or Bccc=Ωccc++{\bf B}_{ccc}=\Omega^{++}_{ccc}. With Bn(){\bf B}_n^{(\prime)} denoted as the baryon octet (decuplet), we find that the BcBn+ν{\bf B}_{c}\to {\bf B}'_n\ell^+\nu_\ell decays are forbidden, while the Ωc0Ω+ν\Omega_c^0\to \Omega^-\ell^+\nu_\ell, Ωcc+Ωc0+ν\Omega_{cc}^+\to\Omega_c^0\ell^+\nu_\ell, and Ωccc++Ωcc++ν\Omega_{ccc}^{++}\to \Omega_{cc}^+\ell^+\nu_\ell decays are the only existing Cabibbo-allowed modes for BcBn+ν{\bf B}'_{c}\to {\bf B}'_n\ell^+\nu_\ell, BccBc+ν{\bf B}_{cc}\to {\bf B}'_c\ell^+\nu_\ell, and BcccBcc()+ν{\bf B}_{ccc}\to {\bf B}_{cc}^{(\prime)}\ell^+\nu_\ell, respectively. We predict the rarely studied BcBn()M{\bf B}_{c}\to {\bf B}_n^{(\prime)}M decays, such as B(Ξc0Λ0Kˉ0,Ξc+Ξ0π+)=(8.3±0.9,8.0±4.1)×103{\cal B}(\Xi_c^0\to\Lambda^0\bar K^0,\,\Xi_c^+\to\Xi^0\pi^+)=(8.3\pm 0.9,8.0\pm 4.1)\times 10^{-3} and B(Λc+Δ++π,Ξc0ΩK+)=(5.5±1.3,4.8±0.5)×103{\cal B}(\Lambda_c^+\to \Delta^{++}\pi^-,\,\Xi_c^0\to\Omega^- K^+)=(5.5\pm 1.3,4.8\pm 0.5)\times 10^{-3}. For the observation, the doubly and triply charmed baryon decays of Ωcc+Ξc+Kˉ0\Omega_{cc}^{+}\to \Xi_c^+\bar K^0, Ξcc++(Ξc+π+\Xi_{cc}^{++}\to (\Xi_c^+\pi^+, Σc++Kˉ0)\Sigma_c^{++}\bar K^0), and Ωccc++(Ξcc++Kˉ0,Ωcc+π+,Ξc+D+)\Omega_{ccc}^{++}\to (\Xi_{cc}^{++}\bar K^0,\Omega_{cc}^+\pi^+,\Xi_c^+ D^+) are the favored Cabibbo-allowed decays, which are accessible to the BESIII and LHCb experiments.Comment: 29 pages, no figure, a typo in the table correcte

    The Optimal Inhomogeneity for Superconductivity: Finite Size Studies

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    We report the results of exact diagonalization studies of Hubbard models on a 4×44\times 4 square lattice with periodic boundary conditions and various degrees and patterns of inhomogeneity, which are represented by inequivalent hopping integrals tt and tt^{\prime}. We focus primarily on two patterns, the checkerboard and the striped cases, for a large range of values of the on-site repulsion UU and doped hole concentration, xx. We present evidence that superconductivity is strongest for UU of order the bandwidth, and intermediate inhomogeneity, 0<t<t0 <t^\prime< t. The maximum value of the ``pair-binding energy'' we have found with purely repulsive interactions is Δpb=0.32t\Delta_{pb} = 0.32t for the checkerboard Hubbard model with U=8tU=8t and t=0.5tt^\prime = 0.5t. Moreover, for near optimal values, our results are insensitive to changes in boundary conditions, suggesting that the correlation length is sufficiently short that finite size effects are already unimportant.Comment: 8 pages, 9 figures; minor revisions; more references adde

    SU(3) symmetry breaking in charmed baryon decays

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    We explore the breaking effects of the SU(3)SU(3) flavor symmetry in the singly Cabibbo-suppressed anti-triplet charmed baryon decays of BcBnM{\bf B}_c\to {\bf B}_n M, with Bc=(Ξc0,Ξc+,Λc+){\bf B}_c=(\Xi_c^0,\Xi_c^+,\Lambda_c^+) and Bn(M){\bf B}_n(M) the baryon (pseudo-scalar) octets. We find that these breaking effects can be used to account for the experimental data on the decay branching ratios of B(Λc+Σ0K+,Λ0K+){\cal B}(\Lambda_c^+\to \Sigma^{0} K^{+},\Lambda^{0} K^{+}) and RK/πR'_{K/\pi}=B(Ξc0ΞK+){\cal B}(\Xi^0_c \to \Xi^- K^+)/B(Ξc0Ξπ+){\cal B}(\Xi^0_c \to \Xi^- \pi^+). In addition, we obtain that B(Ξc0ΞK+,Σπ+)=(4.6±1.7,12.8±3.1)×104{\cal B}(\Xi_{c}^{0} \to \Xi^{-} K^{+},\Sigma^{-} \pi^{+})=(4.6 \pm 1.7,12.8 \pm 3.1)\times 10^{-4}, B(Ξc0pK,Σ+π)=(3.0±1.0,5.2±1.6)×104{\cal B}(\Xi_c^0\to pK^-,\Sigma^+\pi^-)=(3.0 \pm 1.0, 5.2 \pm 1.6)\times 10^{-4} and B(Ξc+Σ0(+)π+(0))=(10.3±1.7)×104{\cal B}(\Xi_c^+\to \Sigma^{0(+)} \pi^{+(0)})=(10.3 \pm 1.7)\times 10^{-4}, which all receive significant contributions from the breaking effects, and can be tested by the BESIII and LHCb experiments.Comment: 12 pages, no figure, revised version accepted by EPJ

    Neural node network and model, and method of teaching same

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    The present invention is a fully connected feed forward network that includes at least one hidden layer 16. The hidden layer 16 includes nodes 20 in which the output of the node is fed back to that node as an input with a unit delay produced by a delay device 24 occurring in the feedback path 22 (local feedback). Each node within each layer also receives a delayed output (crosstalk) produced by a delay unit 36 from all the other nodes within the same layer 16. The node performs a transfer function operation based on the inputs from the previous layer and the delayed outputs. The network can be implemented as analog or digital or within a general purpose processor. Two teaching methods can be used: (1) back propagation of weight calculation that includes the local feedback and the crosstalk or (2) more preferably a feed forward gradient decent which immediately follows the output computations and which also includes the local feedback and the crosstalk. Subsequent to the gradient propagation, the weights can be normalized, thereby preventing convergence to a local optimum. Education of the network can be incremental both on and off-line. An educated network is suitable for modeling and controlling dynamic nonlinear systems and time series systems and predicting the outputs as well as hidden states and parameters. The educated network can also be further educated during on-line processing

    Observations of Giant Pulses from Pulsar PSR B0950+08 using LWA1

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    We report the detection of giant pulse emission from PSR B0950+08 in 24 hours of observations made at 39.4 MHz, with a bandwidth of 16 MHz, using the first station of the Long Wavelength Array, LWA1. We detected 119 giant pulses from PSR B0950+08 (at its dispersion measure), which we define as having SNRs at least 10 times larger than for the mean pulse in our data set. These 119 pulses are 0.035% of the total number of pulse periods in the 24 hours of observations. The rate of giant pulses is about 5.0 per hour. The cumulative distribution of pulse strength SS is a steep power law, N(>S)S4.7N(>S)\propto S^{-4.7}, but much less steep than would be expected if we were observing the tail of a Gaussian distribution of normal pulses. We detected no other transient pulses in a dispersion measure range from 1 to 90 pc cm3^{-3}, in the beam tracking PSR B0950+08. The giant pulses have a narrower temporal width than the mean pulse (17.8 ms, on average, vs. 30.5 ms). The pulse widths are consistent with a previously observed weak dependence on observing frequency, which may be indicative of a deviation from a Kolmogorov spectrum of electron density irregularities along the line of sight. The rate and strength of these giant pulses is less than has been observed at \sim100 MHz. Additionally, the mean (normal) pulse flux density we observed is less than at \sim100 MHz. These results suggest this pulsar is weaker and produces less frequent giant pulses at 39 MHz than at 100 MHz.Comment: 27 pages, 12 figures, typos correcte

    A New Population of High-z, Dusty Lyα Emitters and Blobs Discovered by WISE: Feedback Caught in the Act?

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    By combining data from the NASA Wide-field Infrared Survey Explorer (WISE) mission with optical spectroscopy from the W. M. Keck telescope, we discover a mid-IR color criterion that yields a 78% success rate in identifying rare, typically radio-quiet, 1.6 ≾ z ≾ 4.6 dusty Lyα emitters (LAEs). Of these, at least 37% have emission extended on scales of 30-100 kpc and are considered Lyα "blobs" (LABs). The objects have a surface density of only ~0.1 deg^(–2), making them rare enough that they have been largely missed in deep, small area surveys. We measured spectroscopic redshifts for 92 of these galaxies, and find that the LAEs (LABs) have a median redshift of 2.3 (2.5). The WISE photometry coupled with data from Herschel (Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA) reveals that these galaxies are in the Hyper Luminous IR galaxy regime (L IR ≳ 10^(13)-10^(14) L_☉) and have warm colors. They are typically more luminous and warmer than other dusty, z ~ 2 populations such as submillimeter-selected galaxies and dust-obscured galaxies. These traits are commonly associated with the dust being illuminated by intense active galactic nucleus activity. We hypothesize that the combination of spatially extended Lyα, large amounts of warm IR-luminous dust, and rarity (implying a short-lived phase) can be explained if the galaxies are undergoing brief, intense "feedback" transforming them from an extreme dusty starburst/QSO into a mature galaxy
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