12,164 research outputs found
Heroes of Berlin Wall Struggle
When the Berlin Wall fell 25 years ago, on Nov. 9, 1989, symbolically signaling the end of the Cold War, it was no surprise that many credited President Ronald Reagan and Soviet leader Mikhail Gorbachev for bringing it down.
But the true heroes behind the fall of the Berlin Wall are those Eastern Europeans whose protests and political pressure started chipping away at the wall years before. East German citizens from a variety of political backgrounds and occupations risked their freedom in protests against communist policies and one-party rule in what they called the peaceful revolution. [excerpt
HI and Cosmology: What We Need To Know
There are three distinct regimes in which radio observations of the
redshifted 21 cm line of HI can contribute directly to cosmology in unique
ways. The regimes are naturally divided by redshift, from high to low, into:
inflationary physics, the Dark Ages and reionization, and galaxy evolution and
Dark Energy. Each measurement presents its own set of technical, theoretical,
and observational challenges, making "what we need to know" not so much an
astrophysical question at this early stage as a comprehensive experimental
question. A wave of new pathfinder projects are exploring the fundamental
aspects of what we need to know (and what we should expect to learn in the
coming years) in order to achieve the goals of the Square Kilometer Array (SKA)
and beyond.Comment: From AIP Conference Proceedings, Volume 1035, 2008, "The Evolution of
Galaxies through the Neutral Hydrogen Window". 7 page
Design and Evaluation of Menu Systems for Immersive Virtual Environments
Interfaces for system control tasks in virtual environments (VEs) have not been extensively studied. This paper focuses on various types of menu systems to be used in such environments. We describe the design of the TULIP menu, a menu system using Pinch Glovesâ„¢, and compare it to two common alternatives: floating menus and pen and tablet menus. These three menus were compared in an empirical evaluation. The pen and tablet menu was found to be significantly faster, while users had a preference for TULIP. Subjective discomfort levels were also higher with the floating menus and pen and tablet
Learning 3D Navigation Protocols on Touch Interfaces with Cooperative Multi-Agent Reinforcement Learning
Using touch devices to navigate in virtual 3D environments such as computer
assisted design (CAD) models or geographical information systems (GIS) is
inherently difficult for humans, as the 3D operations have to be performed by
the user on a 2D touch surface. This ill-posed problem is classically solved
with a fixed and handcrafted interaction protocol, which must be learned by the
user. We propose to automatically learn a new interaction protocol allowing to
map a 2D user input to 3D actions in virtual environments using reinforcement
learning (RL). A fundamental problem of RL methods is the vast amount of
interactions often required, which are difficult to come by when humans are
involved. To overcome this limitation, we make use of two collaborative agents.
The first agent models the human by learning to perform the 2D finger
trajectories. The second agent acts as the interaction protocol, interpreting
and translating to 3D operations the 2D finger trajectories from the first
agent. We restrict the learned 2D trajectories to be similar to a training set
of collected human gestures by first performing state representation learning,
prior to reinforcement learning. This state representation learning is
addressed by projecting the gestures into a latent space learned by a
variational auto encoder (VAE).Comment: 17 pages, 8 figures. Accepted at The European Conference on Machine
Learning and Principles and Practice of Knowledge Discovery in Databases 2019
(ECMLPKDD 2019
Combining WASP and Kepler data: the case of the Sct star KIC 7106205
Ground-based photometric observations from Wide Angle Search for Planets (WASP) have been calibrated, scaled and combined with Kepler observations of the δ Sct star KIC 7106205, allowing us to extend the time base of the study of the unexplained amplitude and frequency variation of a single pressure mode at ν = 13.3942 d−1 by 2 yr. Analysis of the combined data sets, spanning 6 yr, show that the amplitude modulation in KIC 7106205 has a much larger range than a previous study of the Kepler data alone indicated. The single pressure mode decreased from 11.70 ± 0.05 mmag in 2007, to 5.87 ± 0.03 mmag in 2009, and to 0.58 ± 0.06 mmag in 2013. Observations of the decrease in mode amplitude have now been extended back 2 yr before the launch of Kepler. With observations over a longer time span, we have been able to further investigate the decrease in mode amplitude in KIC 7106205 to address the question of mode amplitude stability in δ Sct stars. This study highlights the usefulness of the WASP data set for extending studies of some Kepler variable stars
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