6,026 research outputs found
The 10 to the 8th power bit solid state spacecraft data recorder
The results are summarized of a program to demonstrate the feasibility of Bubble Domain Memory Technology as a mass memory medium for spacecraft applications. The design, fabrication and test of a partially populated 10 to the 8th power Bit Data Recorder using 100 Kbit serial bubble memory chips is described. Design tradeoffs, design approach and performance are discussed. This effort resulted in a 10 to the 8th power bit recorder with a volume of 858.6 cu in and a weight of 47.2 pounds. The recorder is plug reconfigurable, having the capability of operating as one, two or four independent serial channel recorders or as a single sixteen bit byte parallel input recorder. Data rates up to 1.2 Mb/s in a serial mode and 2.4 Mb/s in a parallel mode may be supported. Fabrication and test of the recorder demonstrated the basic feasibility of Bubble Domain Memory technology for such applications. Test results indicate the need for improvement in memory element operating temperature range and detector performance
Towards Identifying and closing Gaps in Assurance of autonomous Road vehicleS - a collection of Technical Notes Part 1
This report provides an introduction and overview of the Technical Topic Notes (TTNs) produced in the Towards Identifying and closing Gaps in Assurance of autonomous Road vehicleS (Tigars) project. These notes aim to support the development and evaluation of autonomous vehicles. Part 1 addresses: Assurance-overview and issues, Resilience and Safety Requirements, Open Systems Perspective and Formal Verification and Static Analysis of ML Systems. Part 2: Simulation and Dynamic Testing, Defence in Depth and Diversity, Security-Informed Safety Analysis, Standards and Guidelines
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Towards Identifying and closing Gaps in Assurance of autonomous Road vehicleS - a collection of Technical Notes Part 2
This report provides an introduction and overview of the Technical Topic Notes (TTNs) produced in the Towards Identifying and closing Gaps in Assurance of autonomous Road vehicleS (Tigars) project. These notes aim to support the development and evaluation of autonomous vehicles. Part 1 addresses: Assurance-overview and issues, Resilience and Safety Requirements, Open Systems Perspective and Formal Verification and Static Analysis of ML Systems. This report is Part 2 and discusses: Simulation and Dynamic Testing, Defence in Depth and Diversity, Security-Informed Safety Analysis, Standards and Guidelines
A field-induced reentrant insulator state of a gap-closed topological insulator (Bi_{1-x}Sb_x) in quantum-limit states
In the extreme quantum limit states under high magnetic fields, enhanced
electronic correlation effects can stabilize anomalous quantum states. Using
band-tuning with a magnetic field, we realized a spin-polarized quantum limit
state in the field-induced semimetallic phase of a topological insulator
Bi_{1-x}Sb_x. Further increase in the field injects more electrons and holes to
this state and results in an unexpected reentrant insulator state in this
topological semimetallic state. A single-particle picture cannot explain this
reentrant insulator state, reminiscent of phase transitions due to many-body
effects. Estimates of the binding energy and spacing of electron-hole pairs and
the thermal de Broglie wavelength indicate that Bi_{1-x}Sb_x may host the
excitonic insulator phase in this extreme environment.Comment: 26pages, 6figure
Entropic torque
Quantitative predictions are presented of a depletion-induced torque and
force acting on a single colloidal hard rod immersed in a solvent of hard
spheres close to a planar hard wall. This torque and force, which are entirely
of entropic origin, may play an important role for the key-lock principle,
where a biological macromolecule (the key) is only functional in a particular
orientation with respect to a cavity (the lock)
The cross-frequency mediation mechanism of intracortical information transactions
In a seminal paper by von Stein and Sarnthein (2000), it was hypothesized
that "bottom-up" information processing of "content" elicits local, high
frequency (beta-gamma) oscillations, whereas "top-down" processing is
"contextual", characterized by large scale integration spanning distant
cortical regions, and implemented by slower frequency (theta-alpha)
oscillations. This corresponds to a mechanism of cortical information
transactions, where synchronization of beta-gamma oscillations between distant
cortical regions is mediated by widespread theta-alpha oscillations. It is the
aim of this paper to express this hypothesis quantitatively, in terms of a
model that will allow testing this type of information transaction mechanism.
The basic methodology used here corresponds to statistical mediation analysis,
originally developed by (Baron and Kenny 1986). We generalize the classical
mediator model to the case of multivariate complex-valued data, consisting of
the discrete Fourier transform coefficients of signals of electric neuronal
activity, at different frequencies, and at different cortical locations. The
"mediation effect" is quantified here in a novel way, as the product of "dual
frequency RV-coupling coefficients", that were introduced in (Pascual-Marqui et
al 2016, http://arxiv.org/abs/1603.05343). Relevant statistical procedures are
presented for testing the cross-frequency mediation mechanism in general, and
in particular for testing the von Stein & Sarnthein hypothesis.Comment: https://doi.org/10.1101/119362 licensed as CC-BY-NC-ND 4.0
International license: http://creativecommons.org/licenses/by-nc-nd/4.0
QED Corrections to Neutrino Electron Scattering
We evaluate the O(alpha) QED corrections to the recoil electron energy
spectrum in the process nu_l + e --> nu_l + e (+gamma), where (+gamma)
indicates the possible emission of a photon and l=e, mu or tau. The soft and
hard bremsstrahlung differential cross sections are computed for an arbitrary
value of the photon energy threshold. We also study the O(alpha) QED
corrections to the differential cross section with respect to the total
combined energy of the recoil electron and a possible accompanying photon.
Their difference from the corrections to the electron spectrum is investigated.
We discuss the relevance and applicability of both radiative corrections,
emphasizing their role in the analysis of precise solar neutrino electron
scattering experiments.Comment: 14 pages + 10 figures. Minimal changes, published versio
Evidence of Luttinger liquid behavior in one-dimensional dipolar quantum gases
The ground state and structure of a one-dimensional Bose gas with dipolar
repulsions is investigated at zero temperature by a combined Reptation Quantum
Monte Carlo (RQMC) and bosonization approach. A non trivial Luttinger-liquid
behavior emerges in a wide range of intermediate densities, evolving into a
Tonks-Girardeau gas at low density and into a classical quasi-ordered state at
high density. The density dependence of the Luttinger exponent is extracted
from the numerical data, providing analytical predictions for observable
quantities, such as the structure factor and the momentum distribution. We
discuss the accessibility of such predictions in current experiments with
ultracold atomic and molecular gases.Comment: 4 pages, 3 EPS figures, Revtex
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