14,616 research outputs found
Responsible Conduct: The Ethics of It All in Life and Research
The teaching and learning of ethics as applied generally to the human condition as well as specifically to ethics in research are explored in this discourse. This first section focuses on individual moral dilemmas whereas the second depicts professional ethics in a more complicated tension between the personal moral self and the professional rules, regulations, and ethical expectations of a particular institution
Multi-Robot Transfer Learning: A Dynamical System Perspective
Multi-robot transfer learning allows a robot to use data generated by a
second, similar robot to improve its own behavior. The potential advantages are
reducing the time of training and the unavoidable risks that exist during the
training phase. Transfer learning algorithms aim to find an optimal transfer
map between different robots. In this paper, we investigate, through a
theoretical study of single-input single-output (SISO) systems, the properties
of such optimal transfer maps. We first show that the optimal transfer learning
map is, in general, a dynamic system. The main contribution of the paper is to
provide an algorithm for determining the properties of this optimal dynamic map
including its order and regressors (i.e., the variables it depends on). The
proposed algorithm does not require detailed knowledge of the robots' dynamics,
but relies on basic system properties easily obtainable through simple
experimental tests. We validate the proposed algorithm experimentally through
an example of transfer learning between two different quadrotor platforms.
Experimental results show that an optimal dynamic map, with correct properties
obtained from our proposed algorithm, achieves 60-70% reduction of transfer
learning error compared to the cases when the data is directly transferred or
transferred using an optimal static map.Comment: 7 pages, 6 figures, accepted at the 2017 IEEE/RSJ International
Conference on Intelligent Robots and System
Alcohol Prohibition and Cirrhosis
This paper uses state-level data on cirrhosis death rates to examine the impact of state prohibitions, pre-1920 federal anti-alcohol policies, and constitutional prohibition on cirrhosis State prohibitions had a minimal impact on cirrhosis, especially during the pre-1920 period. Pre-1920 federal anti-alcohol policies may have contributed to the decline in cirrhosis that occurred before 1920, although other factors were likely substantial influences as well. Constitutional prohibition reduced cirrhosis by about 10-20 percent.
On the Construction of Safe Controllable Regions for Affine Systems with Applications to Robotics
This paper studies the problem of constructing in-block controllable (IBC)
regions for affine systems. That is, we are concerned with constructing regions
in the state space of affine systems such that all the states in the interior
of the region are mutually accessible through the region's interior by applying
uniformly bounded inputs. We first show that existing results for checking
in-block controllability on given polytopic regions cannot be easily extended
to address the question of constructing IBC regions. We then explore the
geometry of the problem to provide a computationally efficient algorithm for
constructing IBC regions. We also prove the soundness of the algorithm. We then
use the proposed algorithm to construct safe speed profiles for different
robotic systems, including fully-actuated robots, ground robots modeled as
unicycles with acceleration limits, and unmanned aerial vehicles (UAVs).
Finally, we present several experimental results on UAVs to verify the
effectiveness of the proposed algorithm. For instance, we use the proposed
algorithm for real-time collision avoidance for UAVs.Comment: 17 pages, 18 figures, under review for publication in Automatic
Dispersion and the electron-phonon interaction in a single heterostructure
We investigate the electron-phonon interaction in a polar-polar single heterostructure through the use of the linear combination of hybrid phonon modes, considering the role of longitudinal optical, transverse optical and interface modes, using a continuum model that accounts for both mechanical and electrical continuity over a heterostructure interface. We discuss the use of other models for such systems, such as the bulk phonon (3DP) and dielectric continuum (DC) models, using previously developed sum-rules to explain the limitations on their validity. We find that our linear combination (LC) model gives an excellent agreement with scattering rates previously derived using the 3DP and DC models when the lattice dispersion is weak enough to be ignored, however, when there is a noticeable lattice dispersion, the LC model returns a different answer, suggesting that interface modes play a much greater part in the scattering characteristics of the system under certain conditions. We also discuss the remote phonon effect in polar/polar heterostructures
Hot phonon effects on high field transport in GaN & AlN
We have studied the effects of hot phonons on the high-field transport in GaN & AlN. The dynamics of the non-equilibrium electron-LO phonon system is studied via an ensemble Monte-Carlo code. We find that under steady-state conditions the hot-phonons cause the randomization of the electron momentum and increase their mean energy leading to diffusive heating. Average electron energies of three and two times those in the equilibrium phonon cases are found for GaN and AlN at applied fields of 100 kV/cm and 350 kV/cm respectively. The electron velocity is reduced compared to the case with equilibrium phonons at the lattice temperature. In the transient regime peak velocities reached at overshoot are reduced when non-equilibrium phonons are taken into account
Comparative Response of Two Hydrilla Strains to Fluridone
Experiments were conducted in a controlled-environmental
growth chamber to evaluate the response of two strains of
the invasive submersed plant
Hydrilla verticillata
(L.f.) Royle to fluridone (1-methyl-3-phenyl-5-[3-trifluoromethyl)phenyl]-
4(1H)-pyridinone). (PDF has 6 pages.
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