391 research outputs found
Human-Machine Interface for Tele-Robotic Operation: Mapping of Tongue Movements Based on Aural Flow Monitoring
2004 IEEE International Conference on Intelligent Robots and Systems (IROS), October, 2004 (Awarded “Best Paper in Conference”
Adaptation Strategies for Personalized Gait Neuroprosthetics
Personalization of gait neuroprosthetics is paramount to ensure their efficacy for users, who experience severe limitations in mobility without an assistive device. Our goal is to develop assistive devices that collaborate with and are tailored to their users, while allowing them to use as much of their existing capabilities as possible. Currently, personalization of devices is challenging, and technological advances are required to achieve this goal. Therefore, this paper presents an overview of challenges and research directions regarding an interface with the peripheral nervous system, an interface with the central nervous system, and the requirements of interface computing architectures. The interface should be modular and adaptable, such that it can provide assistance where it is needed. Novel data processing technology should be developed to allow for real-time processing while accounting for signal variations in the human. Personalized biomechanical models and simulation techniques should be developed to predict assisted walking motions and interactions between the user and the device. Furthermore, the advantages of interfacing with both the brain and the spinal cord or the periphery should be further explored. Technological advances of interface computing architecture should focus on learning on the chip to achieve further personalization. Furthermore, energy consumption should be low to allow for longer use of the neuroprosthesis. In-memory processing combined with resistive random access memory is a promising technology for both. This paper discusses the aforementioned aspects to highlight new directions for future research in gait neuroprosthetics.AK is funded by a faculty endowment by adidas AG. MA, SKH, NM, MN, RJQ, R-DR, RJT are supported by NSF CPS grant 1739800, VA Merit Reviews A2275-R and 3056, and the NIH (5T32EB004314-15, R01 NS040547-13). MS and AG are funded by the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation programme (Grant agreement No. 803035). AJd-A, JMF-L, and JCM are supported by coordinated grants RTI2018-097290-B-C31/C32/C33 (TAILOR project) funded by MCIN/AEI/10.13039/501100011033 and by “ERDF A way of making Europe”. MR is funded by the Lo3-ML project by the Federal Ministry for Education, Science and Technology (BMBF) (Funding No. 16ES1142K). AC, SS, and MV were supported by the European Research Council (ERC) under the project NGBMI (759370), the Einstein Stiftung Berlin, the ERA-NET NEURON project HYBRIDMIND (BMBF, 01GP2121A and -B) and the BMBF project NEO (13GW0483C)
The G0 Experiment: Apparatus for Parity-Violating Electron Scattering Measurements at Forward and Backward Angles
In the G0 experiment, performed at Jefferson Lab, the parity-violating
elastic scattering of electrons from protons and quasi-elastic scattering from
deuterons is measured in order to determine the neutral weak currents of the
nucleon. Asymmetries as small as 1 part per million in the scattering of a
polarized electron beam are determined using a dedicated apparatus. It consists
of specialized beam-monitoring and control systems, a cryogenic hydrogen (or
deuterium) target, and a superconducting, toroidal magnetic spectrometer
equipped with plastic scintillation and aerogel Cerenkov detectors, as well as
fast readout electronics for the measurement of individual events. The overall
design and performance of this experimental system is discussed.Comment: Submitted to Nuclear Instruments and Method
The Fueling and Evolution of AGN: Internal and External Triggers
In this chapter, I review the fueling and evolution of active galactic nuclei
(AGN) under the influence of internal and external triggers, namely intrinsic
properties of host galaxies (morphological or Hubble type, color, presence of
bars and other non-axisymmetric features, etc) and external factors such as
environment and interactions. The most daunting challenge in fueling AGN is
arguably the angular momentum problem as even matter located at a radius of a
few hundred pc must lose more than 99.99 % of its specific angular momentum
before it is fit for consumption by a BH. I review mass accretion rates,
angular momentum requirements, the effectiveness of different fueling
mechanisms, and the growth and mass density of black BHs at different epochs. I
discuss connections between the nuclear and larger-scale properties of AGN,
both locally and at intermediate redshifts, outlining some recent results from
the GEMS and GOODS HST surveys.Comment: Invited Review Chapter to appear in LNP Volume on "AGN Physics on All
Scales", Chapter 6, in press. 40 pages, 12 figures. Typo in Eq 5 correcte
Transverse Beam Spin Asymmetries in Forward-Angle Elastic Electron-Proton Scattering
We have measured the beam-normal single-spin asymmetry in elastic scattering
of transversely-polarized 3 GeV electrons from unpolarized protons at Q^2 =
0.15, 0.25 (GeV/c)^2. The results are inconsistent with calculations solely
using the elastic nucleon intermediate state, and generally agree with
calculations with significant inelastic hadronic intermediate state
contributions. A_n provides a direct probe of the imaginary component of the
2-gamma exchange amplitude, the complete description of which is important in
the interpretation of data from precision electron-scattering experiments.Comment: 5 pages, 3 figures, submitted to Physical Review Letters; shortened
to meet PRL length limit, clarified some text after referee's comment
Strange Quark Contributions to Parity-Violating Asymmetries in the Forward G0 Electron-Proton Scattering Experiment
We have measured parity-violating asymmetries in elastic electron-proton
scattering over the range of momentum transfers 0.12 < Q^2 < 1.0 GeV^2. These
asymmetries, arising from interference of the electromagnetic and neutral weak
interactions, are sensitive to strange quark contributions to the currents of
the proton. The measurements were made at JLab using a toroidal spectrometer to
detect the recoiling protons from a liquid hydrogen target. The results
indicate non-zero, Q^2 dependent, strange quark contributions and provide new
information beyond that obtained in previous experiments.Comment: 5 pages, 2 figure
Search for Higgs bosons decaying to tautau pairs in ppbar collisions at sqrt(s) = 1.96 TeV
We present a search for the production of neutral Higgs bosons decaying into
tautau pairs in ppbar collisions at a center-of-mass energy of 1.96 TeV. The
data, corresponding to an integrated luminosity of 5.4 fb-1, were collected by
the D0 experiment at the Fermilab Tevatron Collider. We set upper limits at the
95% C.L. on the product of production cross section and branching ratio for a
scalar resonance decaying into tautau pairs, and we then interpret these limits
as limits on the production of Higgs bosons in the minimal supersymmetric
standard model (MSSM) and as constraints in the MSSM parameter space.Comment: 7 pages, 5 figures, submitted to PL
Measurement of the photon-jet production differential cross section in collisions at \sqrt{s}=1.96~\TeV
We present measurements of the differential cross section dsigma/dpT_gamma
for the inclusive production of a photon in association with a b-quark jet for
photons with rapidities |y_gamma|< 1.0 and 30<pT_gamma <300 GeV, as well as for
photons with 1.5<|y_gamma|< 2.5 and 30< pT_gamma <200 GeV, where pT_gamma is
the photon transverse momentum. The b-quark jets are required to have pT>15 GeV
and rapidity |y_jet| < 1.5. The results are based on data corresponding to an
integrated luminosity of 8.7 fb^-1, recorded with the D0 detector at the
Fermilab Tevatron Collider at sqrt(s)=1.96 TeV. The measured cross
sections are compared with next-to-leading order perturbative QCD calculations
using different sets of parton distribution functions as well as to predictions
based on the kT-factorization QCD approach, and those from the Sherpa and
Pythia Monte Carlo event generators.Comment: 10 pages, 9 figures, submitted to Phys. Lett.
Quantification and characterisation of porosity in selectively laser melted Al–Si10–Mg using x-ray computed tomography
We used X-ray computed tomography (CT), microscopy and hardness measurements to study Al–Si10–Mg produced by selective laser melting (SLM). Specimens were subject to a series of heat treatments including annealing and precipitation hardening. The specimen interiors were imaged with X-ray CT, allowing the non-destructive quantification and characterisation of pores, including their spatial distribution. The specimens had porosities less than 0.1%, but included some pores with effective cross-sectional diameters up to 260 μm. The largest pores were highly anisotropic, being flat and lying in the plane normal to the build direction. Annealing cycles caused significant coarsening of the microstructure and a reduction of the hardness from (114 ± 3) HV, in the as-built state, to (45 ± 1) HV, while precipitation hardening increased this to a final hardness of (59 ± 1) HV. The pore size and shape distributions were unaffected by the heat treatments. We demonstrate the applicability of CT measurements and quantitative defect analysis for the purposes of SLM process monitoring and refinement
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