53 research outputs found
A Critical Review of the US State Department's 2015 Progress Report on Haiti
This review, published jointly by the Center for Economic and Policy Research and the Haiti Advocacy Working Group, looks at the US State Department's annual reports on US assistance to Haiti mandated under the 2014 Assessing Progress in Haiti Act. The review analyzes the various components of the reports and identifies significant omissions and deficiencies, including incomplete data, a failure to link projects and outcomes, and a failure to adequately identify mistakes and lessons learned.In addition, the review shares feedback from Haitian civil society groups and makes recommendations on how the US Agency for International Development and the State Department can improve future progress reports
Time-Contrastive Networks: Self-Supervised Learning from Video
We propose a self-supervised approach for learning representations and
robotic behaviors entirely from unlabeled videos recorded from multiple
viewpoints, and study how this representation can be used in two robotic
imitation settings: imitating object interactions from videos of humans, and
imitating human poses. Imitation of human behavior requires a
viewpoint-invariant representation that captures the relationships between
end-effectors (hands or robot grippers) and the environment, object attributes,
and body pose. We train our representations using a metric learning loss, where
multiple simultaneous viewpoints of the same observation are attracted in the
embedding space, while being repelled from temporal neighbors which are often
visually similar but functionally different. In other words, the model
simultaneously learns to recognize what is common between different-looking
images, and what is different between similar-looking images. This signal
causes our model to discover attributes that do not change across viewpoint,
but do change across time, while ignoring nuisance variables such as
occlusions, motion blur, lighting and background. We demonstrate that this
representation can be used by a robot to directly mimic human poses without an
explicit correspondence, and that it can be used as a reward function within a
reinforcement learning algorithm. While representations are learned from an
unlabeled collection of task-related videos, robot behaviors such as pouring
are learned by watching a single 3rd-person demonstration by a human. Reward
functions obtained by following the human demonstrations under the learned
representation enable efficient reinforcement learning that is practical for
real-world robotic systems. Video results, open-source code and dataset are
available at https://sermanet.github.io/imitat
Pressure-Induced Effects on the Structure of the FeSe Superconductor
A polycrystalline sample of FeSe, which adopts the tetragonal PbO-type
structure (P4/nmm) at room temperature, has been prepared using solid state
reaction. We have investigated pressure-induced structural changes in
tetragonal FeSe at varying hydrostatic pressures up to 0.6 GPa in the
orthorhombic (T = 50 K) and tetragonal (T = 190 K) phases using high resolution
neutron powder diffraction. We report that the structure is quite compressible
with a Bulk modulus around 31 GPa to 33 GPa and that the pressure response is
anisotropic with a larger compressibility along the c-axis. Key bond angles of
the SeFe4 pyramids and FeSe4 tetrahedra are also determined as a function of
pressure
Synthesis and asymmetric hydrogenation of (3E)-1-benzyl-3-[(2-oxopyridin-1(2H)-yl)methylidene]piperidine-2,6-dione
The synthesis of (3E)-1-benzyl-3-[(2-oxopyridin-1(2H)-yl)methylidene]piperidine-2,6-dione 4 from N-benzylglutarimide was achieved in three steps. The asymmetric hydrogenation of 4 gave either the product of partial reduction (10) or full reduction (13), depending on the catalyst which was employed, in high ee in each case. Attempts at asymmetric transfer hydrogenation (ATH) of 4 resulted in formation of a racemic product
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