2,878 research outputs found
Data management study, volume 5. Appendix K - Contractor data package data management /DM/ Final report
Contractor data management system for Voyager projec
Thermo-acoustic wave propagation and reflection near the liquid-gas critical point
We study the thermo-acoustic wave propagation and reflection near the
liquid-gas critical point. Specifically, we perform a numerical investigation
of the acoustic responses in a near-critical fluid to thermal perturbations
based on the same setup of a recent ultrasensitive interferometry measurement
in CO2 [Y. Miura et al. Phys. Rev. E 74, 010101(R) (2006)]. The numerical
results agree well with the experimental data. New features regarding the
reflection pattern of thermo-acoustic waves near the critical point under pulse
perturbations are revealed by the proper inclusion of the critically diverging
bulk viscosity.Comment: 14 pages, 4 figures, Accepted by PRE (Rapid Communication
Elliptic Phases: A Study of the Nonlinear Elasticity of Twist-Grain Boundaries
We develop an explicit and tractable representation of a twist-grain-boundary
phase of a smectic A liquid crystal. This allows us to calculate the
interaction energy between grain boundaries and the relative contributions from
the bending and compression deformations. We discuss the special stability of
the 90 degree grain boundaries and discuss the relation of this structure to
the Schwarz D surface.Comment: 4 pages, 2 figure
Anomaly Detection in Autonomous Driving: A Survey
Nowadays, there are outstanding strides towards a future with autonomous
vehicles on our roads. While the perception of autonomous vehicles performs
well under closed-set conditions, they still struggle to handle the unexpected.
This survey provides an extensive overview of anomaly detection techniques
based on camera, lidar, radar, multimodal and abstract object level data. We
provide a systematization including detection approach, corner case level,
ability for an online application, and further attributes. We outline the
state-of-the-art and point out current research gaps.Comment: Daniel Bogdoll and Maximilian Nitsche contributed equally. Accepted
for publication at CVPR 2022 WAD worksho
Doubly connected minimal surfaces and extremal harmonic mappings
The concept of a conformal deformation has two natural extensions:
quasiconformal and harmonic mappings. Both classes do not preserve the
conformal type of the domain, however they cannot change it in an arbitrary
way. Doubly connected domains are where one first observes nontrivial conformal
invariants. Herbert Groetzsch and Johannes C. C. Nitsche addressed this issue
for quasiconformal and harmonic mappings, respectively. Combining these
concepts we obtain sharp estimates for quasiconformal harmonic mappings between
doubly connected domains. We then apply our results to the Cauchy problem for
minimal surfaces, also known as the Bjorling problem. Specifically, we obtain a
sharp estimate of the modulus of a doubly connected minimal surface that
evolves from its inner boundary with a given initial slope.Comment: 35 pages, 2 figures. Minor edits, references adde
Dynamic characterization of multi-component sensors for force and moment
An improved set-up for the characterization of multi-component
sensors for force and moment is presented. It aims at calibrating such
sensors under continuous sinusoidal excitation. Special focus is put on the
design of load masses and adapting elements to activate uniaxial force and
moment components where possible. To identify the motion and acceleration of
the load mass with 6 degrees of freedom, a photogrammetric measurement system
is implemented in the existing set-up. Using the set-up described, different
experiments are performed to analyse a commercial multi-component sensor and
perform a parameter identification for its force components.</p
Experiments on Anomaly Detection in Autonomous Driving by Forward-Backward Style Transfers
Great progress has been achieved in the community of autonomous driving in the past few years. As a safety-critical problem, however, anomaly detection is a huge hurdle towards a large-scale deployment of autonomous vehicles in the real world. While many approaches, such as uncertainty estimation or segmentation-based image resynthesis, are extremely promising, there is more to be explored. Especially inspired by works on anomaly detection based on image resynthesis, we propose a novel approach for anomaly detection through style transfer. We leverage generative models to map an image from its original style domain of road traffic to an arbitrary one and back to generate pixelwise anomaly scores. However, our experiments have proven our hypothesis wrong, and we were unable to produce significant results. Nevertheless, we want to share our findings, so that others can learn from our experiments
Thermoacoustic effects in supercritical fluids near the critical point: Resonance, piston effect, and acoustic emission and reflection
We present a general theory of thermoacoustic phenomena in supercritical
fluids near the critical point in a one-dimensional cell. We take into account
the effects of the heat conduction in the boundary walls and the bulk viscosity
near the critical point. We introduce a coefficient characterizing
reflection of sound with frequency at the boundary. As applications,
we examine the acoustic eigenmodes in the cell, the response to time-dependent
perturbations, sound emission and reflection at the boundary. Resonance and
rapid adiabatic changes are noteworthy. In these processes, the role of the
thermal diffusion layers is enhanced near the critical point because of the
strong critical divergence of the thermal expansion.Comment: 15 pages, 7 figure
Utilización del ''Melment” en las fábricas de elementos prefabricados
Not availableHasta hace poco tiempo existĂa todavĂa la creencia de que solamente con cemento, agua y áridos se podĂa conseguir cualquier calidad de hormigĂłn, considerándose superfinos los aditivos
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