1,686 research outputs found
Measurement of the squeezed vacuum state by a bichromatic local oscillator
We present the experimental measurement of a squeezed vacuum state by means
of a bichromatic local oscillator (BLO). A pair of local oscillators at 5
MHz around the central frequency of the fundamental field with
equal power are generated by three acousto-optic modulators and phase-locked,
which are used as a BLO. The squeezed vacuum light are detected by a
phase-sensitive balanced-homodyne detection with a BLO. The baseband signal
around combined with a broad squeezed field can be detected with
the sensitivity below the shot-noise limit, in which the baseband signal is
shifted to the vicinity of 5 MHz (the half of the BLO separation). This work
has the important applications in quantum state measurement and quantum
informatio
Biological Lasers for Biomedical Applications
A biolaser utilizes biological materials as part of its gain medium and/or part of its cavity. It can also be a micro- or nanosized laser embedded/integrated within biological materials. The biolaser employs lasing emission rather than regular fluorescence as the sensing signal and therefore has a number of unique advantages that can be explored for broad applications in biosensing, labeling, tracking, contrast agent development, and bioimaging. This article reports on the progress in biolasers with focus on the work done in the past five years. In the end, the possible future directions of the biolaser are discussed.Biolasers and their applications in biology and biomedicine are reviewed in this progress report. The biolaser employs lasing emission rather than regular fluorescence as the sensing signal and therefore has a number of unique advantages that can be explored for broad applications in biosensing, labeling, tracking, contrast agent development, and bioimaging.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/151258/1/adom201900377.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/151258/2/adom201900377_am.pd
Tied Block Convolution: Leaner and Better CNNs with Shared Thinner Filters
Convolution is the main building block of convolutional neural networks
(CNN). We observe that an optimized CNN often has highly correlated filters as
the number of channels increases with depth, reducing the expressive power of
feature representations. We propose Tied Block Convolution (TBC) that shares
the same thinner filters over equal blocks of channels and produces multiple
responses with a single filter. The concept of TBC can also be extended to
group convolution and fully connected layers, and can be applied to various
backbone networks and attention modules. Our extensive experimentation on
classification, detection, instance segmentation, and attention demonstrates
TBC's significant across-the-board gain over standard convolution and group
convolution. The proposed TiedSE attention module can even use 64 times fewer
parameters than the SE module to achieve comparable performance. In particular,
standard CNNs often fail to accurately aggregate information in the presence of
occlusion and result in multiple redundant partial object proposals. By sharing
filters across channels, TBC reduces correlation and can effectively handle
highly overlapping instances. TBC increases the average precision for object
detection on MS-COCO by 6% when the occlusion ratio is 80%. Our code will be
released.Comment: 13 page
A dynamic programming approach for generalized nearly isotonic optimization
Shape restricted statistical estimation problems have been extensively
studied, with many important practical applications in signal processing,
bioinformatics, and machine learning. In this paper, we propose and study a
generalized nearly isotonic optimization (GNIO) model, which recovers, as
special cases, many classic problems in shape constrained statistical
regression, such as isotonic regression, nearly isotonic regression and
unimodal regression problems. We develop an efficient and easy-to-implement
dynamic programming algorithm for solving the proposed model whose recursion
nature is carefully uncovered and exploited. For special -GNIO
problems, implementation details and the optimal running time
analysis of our algorithm are discussed. Numerical experiments, including the
comparison between our approach and the powerful commercial solver Gurobi for
solving -GNIO and -GNIO problems, on both simulated and real
data sets are presented to demonstrate the high efficiency and robustness of
our proposed algorithm in solving large scale GNIO problems
Joint Learning of Network Topology and Opinion Dynamics Based on Bandit Algorithms
We study joint learning of network topology and a mixed opinion dynamics, in
which agents may have different update rules. Such a model captures the
diversity of real individual interactions. We propose a learning algorithm
based on multi-armed bandit algorithms to address the problem. The goal of the
algorithm is to find each agent's update rule from several candidate rules and
to learn the underlying network. At each iteration, the algorithm assumes that
each agent has one of the updated rules and then modifies network estimates to
reduce validation error. Numerical experiments show that the proposed algorithm
improves initial estimates of the network and update rules, decreases
prediction error, and performs better than other methods such as sparse linear
regression and Gaussian process regression
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