4,713 research outputs found

    REAL: Resilience and Adaptation using Large Language Models on Autonomous Aerial Robots

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    Large Language Models (LLMs) pre-trained on internet-scale datasets have shown impressive capabilities in code understanding, synthesis, and general purpose question-and-answering. Key to their performance is the substantial prior knowledge acquired during training and their ability to reason over extended sequences of symbols, often presented in natural language. In this work, we aim to harness the extensive long-term reasoning, natural language comprehension, and the available prior knowledge of LLMs for increased resilience and adaptation in autonomous mobile robots. We introduce REAL, an approach for REsilience and Adaptation using LLMs. REAL provides a strategy to employ LLMs as a part of the mission planning and control framework of an autonomous robot. The LLM employed by REAL provides (i) a source of prior knowledge to increase resilience for challenging scenarios that the system had not been explicitly designed for; (ii) a way to interpret natural-language and other log/diagnostic information available in the autonomy stack, for mission planning; (iii) a way to adapt the control inputs using minimal user-provided prior knowledge about the dynamics/kinematics of the robot. We integrate REAL in the autonomy stack of a real multirotor, querying onboard an offboard LLM at 0.1-1.0 Hz as part the robot's mission planning and control feedback loops. We demonstrate in real-world experiments the ability of the LLM to reduce the position tracking errors of a multirotor under the presence of (i) errors in the parameters of the controller and (ii) unmodeled dynamics. We also show (iii) decision making to avoid potentially dangerous scenarios (e.g., robot oscillates) that had not been explicitly accounted for in the initial prompt design.Comment: 13 pages, 5 figures, conference worksho

    Biomass yield and heterosis of crosses within and between European winter cultivars of turnip rape (Brassica rapa L.)

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    Because of its high growth rate at low temperatures in early spring, there is renewed interest in Brassica rapa as a winter crop for biomass production in Europe. The available cultivars are not developed for this purpose however. An approach for breeding bioenergy cultivars of B. rapa could be to establish populations from two or more different cultivars with high combining ability. The objective of this study was to evaluate the heterosis for biomass yield in the European winter B. rapa genepool. The genetic variation and heterosis of the biomass parameters: dry matter content, fresh and dry biomass yields were investigated in three cultivars representing different eras of breeding by comparing full-sibs-within and full-sibs-between the cultivars. Field trials were performed at two locations in Germany in 2005–2006. Mean mid-parent heterosis was low with 2.5% in fresh and 3.0% in dry biomass yield in full-sibs-between cultivars. Mean values of individual crosses revealed a higher variation in mid-parent heterosis ranging from 14.6% to −7.5% in fresh biomass yield and from 19.7% to −12.7% in dry biomass yield. The low heterosis observed in hybrids between European winter cultivars can be explained by the low genetic variation between these cultivars as shown earlier with molecular markers. In conclusion, a B. rapa breeding program for biomass production in Europe should not only use European genetic resources, but should also utilize the much wider worldwide variation in this species

    Comprehensive Calculations on the OZI-forbidden Nonleptonic Decays of Orthoquarkonia J/ψ(Υ)ππ,ρπJ/\psi(\Upsilon)\to \pi\pi,\rho\pi

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    In this work, we calculate the decay rates of the OZI-forbidden processes J/ψ(Υ)ππ,ρπJ/\psi(\Upsilon)\to \pi\pi, \rho\pi at the order of the leading-twist distribution amplitude. The process of J/ψ(Υ)π+πJ/\psi(\Upsilon)\to \pi^+ \pi^- violates isospin conservation and the amplitude is explicitly proportional to the isospin violation factor mumdm_u-m_d, our numerical results on their decay rates are consistent with the data. The process J/ψ(Υ)ρπJ/\psi(\Upsilon)\to \rho\pi violates the hadronic helicity conservation and should be suppressed, as indicated in literature, its decay rate can only be proportional to mq2m_q^2 at the order of leading twist. Our theoretical evaluation confirms this statement that the theoretical evaluation on Γ(J/ψ(Υ)ρπ)\Gamma(J/\psi(\Upsilon)\to \rho\pi) is almost one order smaller than the data unless the model parameters take certain extreme values. It may imply that the sizable branching ratio of J/ψ(Υ)ρπJ/\psi(\Upsilon)\to \rho\pi should be explained by either higher twist contributions or other mechanisms.Comment: 25 pages, 1 figure and 4 tables. Numerical results slightly change

    Correlation dynamics between electrons and ions in the fragmentation of D2_2 molecules by short laser pulses

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    We studied the recollision dynamics between the electrons and D2+_2^+ ions following the tunneling ionization of D2_2 molecules in an intense short pulse laser field. The returning electron collisionally excites the D2+_2^+ ion to excited electronic states from there D2+_2^+ can dissociate or be further ionized by the laser field, resulting in D+^+ + D or D+^+ + D+^+, respectively. We modeled the fragmentation dynamics and calculated the resulting kinetic energy spectrum of D+^+ to compare with recent experiments. Since the recollision time is locked to the tunneling ionization time which occurs only within fraction of an optical cycle, the peaks in the D+^+ kinetic energy spectra provides a measure of the time when the recollision occurs. This collision dynamics forms the basis of the molecular clock where the clock can be read with attosecond precision, as first proposed by Corkum and coworkers. By analyzing each of the elementary processes leading to the fragmentation quantitatively, we identified how the molecular clock is to be read from the measured kinetic energy spectra of D+^+ and what laser parameters be used in order to measure the clock more accurately.Comment: 13 pages with 14 figure

    Heat conduction in one dimensional nonintegrable systems

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    Two classes of 1D nonintegrable systems represented by the Fermi-Pasta-Ulam (FPU) model and the discrete ϕ4\phi^4 model are studied to seek a generic mechanism of energy transport in microscopic level sustaining macroscopic behaviors. The results enable us to understand why the class represented by the ϕ4\phi^4 model has a normal thermal conductivity and the class represented by the FPU model does not even though the temperature gradient can be established.Comment: 4 Revtex Pages, 4 Eps figures included, to appear in Phys. Rev. E, March 200

    Initial-state dependence in time-dependent density functional theory

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    Time-dependent density functionals in principle depend on the initial state of the system, but this is ignored in functional approximations presently in use. For one electron it is shown there is no initial-state dependence: for any density, only one initial state produces a well-behaved potential. For two non-interacting electrons with the same spin in one-dimension, an initial potential that makes an alternative initial wavefunction evolve with the same density and current as a ground state is calculated. This potential is well-behaved and can be made arbitrarily different from the original potential

    A Novel Five-Phase Fractional Slot Concentrated Winding with Low Space Harmonic Contents

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    In this article, a novel five-phase fractional-slot concentrated winding (FSCW) with 20-slot/22-pole is presented. It benefits not only the advantages of conventional FSCW but also weak space harmonics of magnetomotive force (MMF). The winding allows eliminating the first sub-order harmonic. The new layout of the winding topology is obtained by a combination of stator shift technique of the winding in the slots with a special coupling of the windings (star-pentagon), using winding function theory. The high performances of the new winding layout are validated using the finite element method (FEM). Compared to the conventional winding, the winding factor and the total harmonic distortion (THD) of MMF are improved by 1.3% and 2.2%, respectively. With the same injection of current density, the average output torque is increased by 1% and the torque ripple is decreased by 60%. The eddy current losses in the permanent magnets (PMs) at rated speed (600 r/min) and 2100 r/min speed are improved by 67% and 56%, respectively
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