4,448 research outputs found
Composite material shear property measurement using the Iosipescu specimen
A detailed evaluation of the suitability of the Iosipescu specimen tested in the modified Wyoming fixture is presented. Finite element analysis and moire interferometry are used to assess the uniformity of the shear stress field in the test section of unidirectional and cross-ply graphite-epoxy composites. The nonuniformity of the strain field and the sensitivity of some fiber orientations to the specimen/fixture contact mechanics are discussed. The shear responses obtained for unidirectional and cross-ply graphite-epoxy composites are discussed and problems associated with anomalous behavior are addressed. An experimental determination of the shear response of a range of material systems using strain gage instrumentation and moire interferometry is performed
Change in the magnitude and mechanisms of global temperature variability with warming
Natural unforced variability in global mean surface air temperature (GMST) can mask or exaggerate human-caused global warming, and thus a complete understanding of this variability is highly desirable. Significant progress has been made in elucidating the magnitude and physical origins of present-day unforced GMST variability, but it has remained unclear how such variability may change as the climate warms. Here we present modelling evidence that indicates that the magnitude of low-frequency GMST variability is likely to decline in a warmer climate and that its generating mechanisms may be fundamentally altered. In particular, a warmer climate results in lower albedo at high latitudes, which yields a weaker albedo feedback on unforced GMST variability. These results imply that unforced GMST variability is dependent on the background climatological conditions, and thus climate model control simulations run under perpetual pre-industrial conditions may have only limited relevance for understanding the unforced GMST variability of the future
Alcohol Use, Abuse, and Dependency in Shanghai
The use of alcohol for social and ceremonial occasions was recorded in Chinese history as early as 1760 B.C. during the Yin Dynasty (Ci-Hai Encyclopedia, 1979:936). The cultural tradition of ancient China placed alcoholic beverages at the center of social occasions, which presumably was the origin of the adage: Without wine, there is no li (or etiquette). Thus, the use of alcoholic beverages has always been accompanied by the concept of propriety and the discharging of one\u27s role obligations m social functions, rather than that of personal indulgence
Calculations of Resonance Coupling Constants in the Scalar Sector of the ENJL Model
We derive the scalar resonance coupling constants of resonance chiral theory
from the Extended Nambu Jona-Lasinio model by using heat-kernel expansion.Comment: 7 page
LAVA: Data Valuation without Pre-Specified Learning Algorithms
Traditionally, data valuation (DV) is posed as a problem of equitably
splitting the validation performance of a learning algorithm among the training
data. As a result, the calculated data values depend on many design choices of
the underlying learning algorithm. However, this dependence is undesirable for
many DV use cases, such as setting priorities over different data sources in a
data acquisition process and informing pricing mechanisms in a data
marketplace. In these scenarios, data needs to be valued before the actual
analysis and the choice of the learning algorithm is still undetermined then.
Another side-effect of the dependence is that to assess the value of individual
points, one needs to re-run the learning algorithm with and without a point,
which incurs a large computation burden. This work leapfrogs over the current
limits of data valuation methods by introducing a new framework that can value
training data in a way that is oblivious to the downstream learning algorithm.
Our main results are as follows. (1) We develop a proxy for the validation
performance associated with a training set based on a non-conventional
class-wise Wasserstein distance between training and validation sets. We show
that the distance characterizes the upper bound of the validation performance
for any given model under certain Lipschitz conditions. (2) We develop a novel
method to value individual data based on the sensitivity analysis of the
class-wise Wasserstein distance. Importantly, these values can be directly
obtained for free from the output of off-the-shelf optimization solvers when
computing the distance. (3) We evaluate our new data valuation framework over
various use cases related to detecting low-quality data and show that,
surprisingly, the learning-agnostic feature of our framework enables a
significant improvement over SOTA performance while being orders of magnitude
faster.Comment: ICLR 2023 Spotlight Latest Updated Version: 2023/12/1
Statistical Origin of Constituent-Quark Scaling in the QGP hadronization
Nonextensive statistics in a Blast-Wave model (TBW) is implemented to
describe the identified hadron production in relativistic p+p and
nucleus-nucleus collisions. Incorporating the core and corona components within
the TBW formalism allows us to describe simultaneously some of the major
observations in hadronic observables at the Relativistic Heavy-Ion Collider
(RHIC): the Number of Constituent Quark Scaling (NCQ), the large radial and
elliptic flow, the effect of gluon saturation and the suppression of hadron
production at high transverse momentum (pT) due to jet quenching. In this
formalism, the NCQ scaling at RHIC appears as a consequence of non-equilibrium
process. Our study also provides concise reference distributions with a least
chi2 fit of the available experimental data for future experiments and models.Comment: 4 pages, 3 figures; added two tables, explained a little bit more on
TBW_p
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