99,933 research outputs found
Low-Complexity Quantized Switching Controllers using Approximate Bisimulation
In this paper, we consider the problem of synthesizing low-complexity
controllers for incrementally stable switched systems. For that purpose, we
establish a new approximation result for the computation of symbolic models
that are approximately bisimilar to a given switched system. The main advantage
over existing results is that it allows us to design naturally quantized
switching controllers for safety or reachability specifications; these can be
pre-computed offline and therefore the online execution time is reduced. Then,
we present a technique to reduce the memory needed to store the control law by
borrowing ideas from algebraic decision diagrams for compact function
representation and by exploiting the non-determinism of the synthesized
controllers. We show the merits of our approach by applying it to a simple
model of temperature regulation in a building
Charge ordering and chemical potential shift in LaSrNiO studied by photoemission spectroscopy
We have studied the chemical potential shift in LaSrNiO and
the charge ordering transition in LaSrNiO by
photoemission spectroscopy. The result shows a large ( 1 eV/hole)
downward shift of the chemical potential with hole doping in the high-doping
regime ( 0.33) while the shift is suppressed in the low-doping
regime ( 0.33). This suppression is attributed to a
segregation of doped holes on a microscopic scale when the hole concentration
is lower than . In the sample, the
photoemission intensity at the chemical potential vanishes below the charge
ordering transition temperature 240 K.Comment: 5 pages, 4 figure
Incremental Visual-Inertial 3D Mesh Generation with Structural Regularities
Visual-Inertial Odometry (VIO) algorithms typically rely on a point cloud
representation of the scene that does not model the topology of the
environment. A 3D mesh instead offers a richer, yet lightweight, model.
Nevertheless, building a 3D mesh out of the sparse and noisy 3D landmarks
triangulated by a VIO algorithm often results in a mesh that does not fit the
real scene. In order to regularize the mesh, previous approaches decouple state
estimation from the 3D mesh regularization step, and either limit the 3D mesh
to the current frame or let the mesh grow indefinitely. We propose instead to
tightly couple mesh regularization and state estimation by detecting and
enforcing structural regularities in a novel factor-graph formulation. We also
propose to incrementally build the mesh by restricting its extent to the
time-horizon of the VIO optimization; the resulting 3D mesh covers a larger
portion of the scene than a per-frame approach while its memory usage and
computational complexity remain bounded. We show that our approach successfully
regularizes the mesh, while improving localization accuracy, when structural
regularities are present, and remains operational in scenes without
regularities.Comment: 7 pages, 5 figures, ICRA accepte
Chemical potential shift and spectral weight transfer in PrCaMnO revealed by photoemission spectroscopy
We have studied the chemical potential shift and changes in the electronic
density of states near the Fermi level () as a function of carrier
concentration in PrCaMnO (PCMO, ) through
the measurements of photoemission spectra. The results showed that the chemical
potential shift was suppressed for x \agt 0.3, where the charge exchange
(CE)-type antiferromagnetic charge-ordered state appears at low temperatures.
We consider this observation to be related to charge self-organization such as
stripe formation on a microscopic scale in this composition range. Together
with the previous observation of monotonous chemical potential shift in
LaSrMnO, we conclude that the tendency toward the charge
self-organization increases with decreasing bandwidth. In the valence band,
spectral weight of the Mn 3 electrons in PCMO was transferred from
1 eV below to the region near with hole doping, leading to a
finite intensity at even in the paramagnetic insulating phase for x \agt
0.3, probably related with the tendency toward charge self-organization. The
finite intensity at in spite of the insulating transport behavior is
consistent with fluctuations involving ferromagnetic metallic states.Comment: 6 pages, 5 figure
Sequential Optimization for Efficient High-Quality Object Proposal Generation
We are motivated by the need for a generic object proposal generation
algorithm which achieves good balance between object detection recall, proposal
localization quality and computational efficiency. We propose a novel object
proposal algorithm, BING++, which inherits the virtue of good computational
efficiency of BING but significantly improves its proposal localization
quality. At high level we formulate the problem of object proposal generation
from a novel probabilistic perspective, based on which our BING++ manages to
improve the localization quality by employing edges and segments to estimate
object boundaries and update the proposals sequentially. We propose learning
the parameters efficiently by searching for approximate solutions in a
quantized parameter space for complexity reduction. We demonstrate the
generalization of BING++ with the same fixed parameters across different object
classes and datasets. Empirically our BING++ can run at half speed of BING on
CPU, but significantly improve the localization quality by 18.5% and 16.7% on
both VOC2007 and Microhsoft COCO datasets, respectively. Compared with other
state-of-the-art approaches, BING++ can achieve comparable performance, but run
significantly faster.Comment: Accepted by TPAM
Sequential optimization for efficient high-quality object proposal generation
We are motivated by the need for a generic object proposal generation algorithm which achieves good balance between object detection recall, proposal localization quality and computational efficiency. We propose a novel object proposal algorithm, BING ++, which inherits the virtue of good computational efficiency of BING [1] but significantly improves its proposal localization quality. At high level we formulate the problem of object proposal generation from a novel probabilistic perspective, based on which our BING++ manages to improve the localization quality by employing edges and segments to estimate object boundaries and update the proposals sequentially. We propose learning the parameters efficiently by searching for approximate solutions in a quantized parameter space for complexity reduction. We demonstrate the generalization of BING++ with the same fixed parameters across different object classes and datasets. Empirically our BING++ can run at half speed of BING on CPU, but significantly improve the localization quality by 18.5 and 16.7 percent on both VOC2007 and Microhsoft COCO datasets, respectively. Compared with other state-of-the-art approaches, BING++ can achieve comparable performance, but run significantly faster
Hyb:A bioinformatics pipeline for the analysis of CLASH (crosslinking, ligation and sequencing of hybrids) data
Peer reviewedPublisher PD
Temperature-dependent photoemission spectral weight transfer and chemical potential shift in PrCaMnO : Implications for charge density modulation
We have studied the temperature dependence of the photoemission spectra of
PrCaMnO (PCMO) with , 0.3 and 0.5. For and 0.5,
we observed a gap in the low-temperature CE-type charge-ordered (CO) phase and
a pseudogap with a finite intensity at the Fermi level () in the
high-temperature paramagnetic insulating (PI) phase. Within the CO phase, the
spectral intensity near gradually increased with temperature. These
observations are consistent with the results of Monte Carlo simulations on a
model including charge ordering and ferromagnetic fluctuations [H. Aliaga {\it
et al.} Phys. Rev. B {\bf 68}, 104405 (2003)]. For , on the other hand,
little temperature dependence was observed within the low-temperature
ferromagnetic insulating (FI) phase and the intensity at remained low in
the high-temperature PI phase. We attribute the difference in the temperature
dependence near between the CO and FI phases to the different correlation
lengths of orbital order between both phases. Furthermore, we observed a
chemical potential shift with temperature due to the opening of the gap in the
FI and CO phases. The doping dependent chemical potential shift was recovered
at low temperatures, corresponding to the disappearance of the doping dependent
change of the modulation wave vector. Spectral weight transfer with hole
concentration was clearly observed at high temperatures but was suppressed at
low temperatures. We attribute this observation to the fixed periodicity with
hole doping in PCMO at low temperatures.Comment: 5pages, 7figure
- …