1,070 research outputs found
HINT: Hierarchical Invertible Neural Transport for Density Estimation and Bayesian Inference
A large proportion of recent invertible neural architectures is based on a
coupling block design. It operates by dividing incoming variables into two
sub-spaces, one of which parameterizes an easily invertible (usually affine)
transformation that is applied to the other. While the Jacobian of such a
transformation is triangular, it is very sparse and thus may lack
expressiveness. This work presents a simple remedy by noting that (affine)
coupling can be repeated recursively within the resulting sub-spaces, leading
to an efficiently invertible block with dense triangular Jacobian. By
formulating our recursive coupling scheme via a hierarchical architecture, HINT
allows sampling from a joint distribution p(y,x) and the corresponding
posterior p(x|y) using a single invertible network. We demonstrate the power of
our method for density estimation and Bayesian inference on a novel data set of
2D shapes in Fourier parameterization, which enables consistent visualization
of samples for different dimensionalities
Implications of the 2002 U.S. Farm Act for World Agriculture
This paper discusses the implications of the Farm Security and Rural Investment Act of 2002 for U.S. agriculture and its subsequent impact on world agricultural prices and world trade
Trend Yield Analysis and Yield Growth Assumptions
Discusses the formulation of assumptions pertaining to yield growth in the crop sector used in developing market projections
Evolution of an equatorial coronal hole structure and the released coronal hole wind stream: Carrington rotations 2039 to 2050
The Sun is a highly dynamic environment that exhibits dynamic behavior on
many different timescales. In particular, coronal holes exhibit temporal and
spatial variability. Signatures of these coronal dynamics are inherited by the
coronal hole wind streams that originate in these regions and can effect the
Earth's magnetosphere. Both the cause of the observed variabilities and how
these translate to fluctuations in the in situ observed solar wind is not yet
fully understood. During solar activity minimum the structure of the magnetic
field typically remains stable over several Carrington rotations (CRs). But how
stable is the solar magnetic field? Here, we address this question by analyzing
the evolution of a coronal hole structure and the corresponding coronal hole
wind stream emitted from this source region over 12 consecutive CRs in 2006. To
this end, we link in situ observations of Solar Wind Ion Composition
Spectrometer (SWICS) onboard the Advanced Composition Explorer (ACE) with
synoptic maps of Michelson Doppler imager (MDI) on the Solar and Heliospheric
Observatory (SOHO) at the photospheric level through a combination of ballistic
back-mapping and a potential field source surface (PFSS) approach. Together,
these track the evolution of the open field line region that is identified as
the source region of a recurring coronal hole wind stream.
We find that the shape of the open field line region and to some extent also
the solar wind properties are influenced by surrounding more dynamic closed
loop regions. We show that the freeze-in order can change within a coronal hole
wind stream on small timescales and illustrate a mechanism that can cause
changes in the freeze-in order. The inferred minimal temperature profile is
variable even within coronal hole wind and is in particular most variable in
the outer corona
Mississippi River Research Conclusions Executive Summary
Briefing paper requested by Senator Bond detailing the conclusions from the Mississippi River research to date
Implications of Alternative Missouri River Flows for Power Plants
The purpose of this paper is to discuss the potential impacts of low Missouri River flows on the power plants operating along the Missouri River and using the Missouri River for cooling water
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