98 research outputs found
Imaging of a vibrating object by Sideband Digital Holography
We obtain quantitative measurements of the oscillation amplitude of vibrating
objects by using sideband digital holography. The frequency sidebands on the
light scattered by the object, shifted by n times the vibration frequency, are
selectively detected by heterodyne holography, and images of the object are
calculated for different orders n. Orders up to n=120 have been observed,
allowing the measurement of amplitudes of oscillation that are significantly
larger than the optical wavelength. Using the positions of the zeros of
intensity for each value of n, we reconstruct the shape of vibration the
object.Comment: 6 page
Accelerating LSTM-based High-Rate Dynamic System Models
In this paper, we evaluate the use of a trained Long Short-Term Memory (LSTM)
network as a surrogate for a Euler-Bernoulli beam model, and then we describe
and characterize an FPGA-based deployment of the model for use in real-time
structural health monitoring applications. The focus of our efforts is the
DROPBEAR (Dynamic Reproduction of Projectiles in Ballistic Environments for
Advanced Research) dataset, which was generated as a benchmark for the study of
real-time structural modeling applications. The purpose of DROPBEAR is to
evaluate models that take vibration data as input and give the initial
conditions of the cantilever beam on which the measurements were taken as
output. DROPBEAR is meant to serve an exemplar for emerging high-rate "active
structures" that can be actively controlled with feedback latencies of less
than one microsecond. Although the Euler-Bernoulli beam model is a well-known
solution to this modeling problem, its computational cost is prohibitive for
the time scales of interest. It has been previously shown that a properly
structured LSTM network can achieve comparable accuracy with less workload, but
achieving sub-microsecond model latency remains a challenge. Our approach is to
deploy the LSTM optimized specifically for latency on FPGA. We designed the
model using both high-level synthesis (HLS) and hardware description language
(HDL). The lowest latency of 1.42 S and the highest throughput of 7.87
Gops/s were achieved on Alveo U55C platform for HDL design.Comment: Accepted at 33rd International Conference on Field-Programmable Logic
and Applications (FPL
Maternally inherited piRNAs direct transient heterochromatin formation at active transposons during early Drosophila embryogenesis
The PIWI-interacting RNA (piRNA) pathway controls transposon expression in animal germ cells, thereby ensuring genome stability over generations. In Drosophila, piRNAs are intergenerationally inherited through the maternal lineage, and this has demonstrated importance in the specification of piRNA source loci and in silencing of I- and P-elements in the germ cells of daughters. Maternally inherited Piwi protein enters somatic nuclei in early embryos prior to zygotic genome activation and persists therein for roughly half of the time required to complete embryonic development. To investigate the role of the piRNA pathway in the embryonic soma, we created a conditionally unstable Piwi protein. This enabled maternally deposited Piwi to be cleared from newly laid embryos within 30 min and well ahead of the activation of zygotic transcription. Examination of RNA and protein profiles over time, and correlation with patterns of H3K9me3 deposition, suggests a role for maternally deposited Piwi in attenuating zygotic transposon expression in somatic cells of the developing embryo. In particular, robust deposition of piRNAs targeting roo, an element whose expression is mainly restricted to embryonic development, results in the deposition of transient heterochromatic marks at active roo insertions. We hypothesize that roo, an extremely successful mobile element, may have adopted a lifestyle of expression in the embryonic soma to evade silencing in germ cells
Inverse problems with partial data for a magnetic Schr\"odinger operator in an infinite slab and on a bounded domain
In this paper we study inverse boundary value problems with partial data for
the magnetic Schr\"odinger operator. In the case of an infinite slab in ,
, we establish that the magnetic field and the electric potential can
be determined uniquely, when the Dirichlet and Neumann data are given either on
the different boundary hyperplanes of the slab or on the same hyperplane. This
is a generalization of the results of [41], obtained for the Schr\"odinger
operator without magnetic potentials. In the case of a bounded domain in ,
, extending the results of [2], we show the unique determination of the
magnetic field and electric potential from the Dirichlet and Neumann data,
given on two arbitrary open subsets of the boundary, provided that the magnetic
and electric potentials are known in a neighborhood of the boundary.
Generalizing the results of [31], we also obtain uniqueness results for the
magnetic Schr\"odinger operator, when the Dirichlet and Neumann data are known
on the same part of the boundary, assuming that the inaccessible part of the
boundary is a part of a hyperplane
Referring to multimodal rehabilitation for patients with musculoskeletal disorders – a register study in primary health care
A systematic review, meta-analysis, and meta-regression of the impact of diurnal intermittent fasting during Ramadan on body weight in healthy subjects aged 16Â years and above
Durability and Efficiency of High Temperature Steam Electrolysis as Studied in the RelHy Project
Surface segregation in binary Cu-Ni and Pt-Ni alloys using Monte Carlo simulation
International audienceMonte Carlo simulation is used to calculate the surface segregation in Cu-Ni and Pt-Ni alloys. The first system is characterized by its segregating tendency with a weak size effect, the second one exhibits an ordering tendency with a strong mismatch. Introduction of an elastic energy term in the Markov chain is necessary for the Pt-Ni system whose segregating properties are dominated by competition between chemical and elastic energy contributions. Interesting information is deduced from this kind of simulation concerning the atomic distributions in the surface plane
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