603 research outputs found

    A scalable, modular leg design for multi-legged stair climbing robots

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    Improving robustness of walking robots has always been problematic. Their complex kinematics and locomotion has always been prone to damage: a broken cable, an unstable foothold or a wrong set of parameters has been an everlasting source of frustration. Nature developed an extraordinary robustness through redundancy and fast adaptation. Theories about decentralized nervous systems has inspired this paper with a novel approach. The presented solution aims at relocating low-level walking behaviours to a network of computers and, more exactly, into the robots individual legs. This paper will not cover the full scope of the software implementation (this is a eld found especially in modular robotics), but presents how such an encapsulated leg with all necessary hardware is built and focuses on the mechanical and kinematic aspect of such legs. It highlights how a robotic leg needs to be designed to tackle structured environments serves as explanatory guide through the design process of legs with integrated PCU and sensors

    Keeping the driver in the loop in conditionally automated driving:A perception-action theory approach

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    In this paper we investigated if keeping the driver in the perception–action loop during automated driving can improve take-over behavior from conditionally automated driving. To meet this aim, we designed an experiment in which visual exposure (perception) and manual control exposure (action) were manipulated. In a dynamic driving simulator experiment, participants (n = 88) performed a non-driving related task either in a head-up display in the windshield (high visual exposure) or on a head-down display near the gear shift (low visual exposure). While driving, participants were either in an intermittent control-mode with four noncritical take-over situations (high manual control exposure), or in a continuous automation-mode throughout the ride (low manual control exposure). In all conditions, a critical take-over had to be carried out after an approximately 13 min ride. Measurements of take-over behavior showed that only high visual exposure had an effect on hands-on reaction time measurements. Both visual exposure and manual control exposure had small to medium sized main effects on time to system deactivation, the maximum velocity of the steering wheel, and the standard deviation of the steering wheel angle. The combined high visual – and high manual control exposure condition led to 0.55 s faster reaction time and 37% less steering variability in comparison to the worst case low visual – and low manual control exposure condition. Together, results corroborate that maintaining visual exposure and manual control exposure during automated driving can be efficacious and suggest that their positive effects are additive

    Exactly Solvable Models: The Road Towards a Rigorous Treatment of Phase Transitions in Finite Systems

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    We discuss exact analytical solutions of a variety of statistical models recently obtained for finite systems by a novel powerful mathematical method, the Laplace-Fourier transform. Among them are a constrained version of the statistical multifragmentation model, the Gas of Bags Model and the Hills and Dales Model of surface partition. Thus, the Laplace-Fourier transform allows one to study the nuclear matter equation of state, the equation of state of hadronic and quark gluon matter and surface partitions on the same footing. A complete analysis of the isobaric partition singularities of these models is done for finite systems. The developed formalism allows us, for the first time, to exactly define the finite volume analogs of gaseous, liquid and mixed phases of these models from the first principles of statistical mechanics and demonstrate the pitfalls of earlier works. The found solutions may be used for building up a new theoretical apparatus to rigorously study phase transitions in finite systems. The strategic directions of future research opened by these exact results are also discussed.Comment: Contribution to the ``World Consensus Initiative III, Texas A & M University, College Station, Texas, USA, February 11-17, 2005, 21

    The s Process: Nuclear Physics, Stellar Models, Observations

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    Nucleosynthesis in the s process takes place in the He burning layers of low mass AGB stars and during the He and C burning phases of massive stars. The s process contributes about half of the element abundances between Cu and Bi in solar system material. Depending on stellar mass and metallicity the resulting s-abundance patterns exhibit characteristic features, which provide comprehensive information for our understanding of the stellar life cycle and for the chemical evolution of galaxies. The rapidly growing body of detailed abundance observations, in particular for AGB and post-AGB stars, for objects in binary systems, and for the very faint metal-poor population represents exciting challenges and constraints for stellar model calculations. Based on updated and improved nuclear physics data for the s-process reaction network, current models are aiming at ab initio solution for the stellar physics related to convection and mixing processes. Progress in the intimately related areas of observations, nuclear and atomic physics, and stellar modeling is reviewed and the corresponding interplay is illustrated by the general abundance patterns of the elements beyond iron and by the effect of sensitive branching points along the s-process path. The strong variations of the s-process efficiency with metallicity bear also interesting consequences for Galactic chemical evolution.Comment: 53 pages, 20 figures, 3 tables; Reviews of Modern Physics, accepte

    Selective laser ionization of N \geq 82 indium isotopes: the new r-process nuclide 135^{135}In

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    Production yields and beta-decay half-lives of very neutron-rich indium isotopes were determined at CERN/ISOLDE using isobaric selectivity of a resonance-ionization laser ion-source. Beta-delayed neutron multiscaling measurements have yielded improved half-lives for 206(6)~ms 132^{132}In, 165(3)~ms 133^{133}In and 141(5)~ms 134^{134}In. With 92(10)~ms 135^{135}In, a new r-process nuclide has been identified which acts as an important `waiting-point' in the In isotopic chain for neutron densities in the range nn1024_n \simeq 10^{24}--1026^{26} n/cm3^3, where the r-matter flow has already passed the A130{\rm A} \simeq 130 abundance-peak region

    Robot companions for citizens

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    This paper describes the scientific vision and objectives of the FET Flagship candidate initiative Robot Companions for Citizens. Robot Companions will be a new generation of machines that will primarily help and assist elderly people in activities of daily living in their workplace, home and in society. They will be the ICT solution for a new sustainable welfare

    High-resolution measurement of the time-modulated orbital electron capture and of the β+\beta^+ decay of hydrogen-like 142^{142}Pm60+^{60+} ions

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    The periodic time modulations, found recently in the two-body orbital electron-capture (EC) decay of both, hydrogen-like 140^{140}Pr58+^{58+} and 142^{142}Pm60+^{60+} ions, with periods near to 7s and amplitudes of about 20%, were re-investigated for the case of 142^{142}Pm60+^{60+} by using a 245 MHz resonator cavity with a much improved sensitivity and time resolution. We observed that the exponential EC decay is modulated with a period T=7.11(11)T = 7.11(11)s, in accordance with a modulation period T=7.12(11)T = 7.12(11) s as obtained from simultaneous observations with a capacitive pick-up, employed also in the previous experiments. The modulation amplitudes amount to aR=0.107(24)a_R = 0.107(24) and aP=0.134(27)a_P = 0.134(27) for the 245 MHz resonator and the capacitive pick-up, respectively. These new results corroborate for both detectors {\it exactly} our previous findings of modulation periods near to 7s, though with {\it distinctly smaller} amplitudes. Also the three-body β+\beta^+ decays have been analyzed. For a supposed modulation period near to 7s we found an amplitude a=0.027(27)a = 0.027(27), compatible with a=0a = 0 and in agreement with the preliminary result a=0.030(30)a = 0.030(30) of our previous experiment. These observations could point at weak interaction as origin of the observed 7s-modulation of the EC decay. Furthermore, the data suggest that interference terms occur in the two-body EC decay, although the neutrinos are not directly observed.Comment: In memoriam of Prof. Paul Kienle, 9 pages, 1 table, 5 figures Phys. Lett. B (2013) onlin

    Transfer of Human Movements to Humanoid Robots

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