2,800 research outputs found
Phase retrieval with background information
Phase retrieval problem has been studied in various applications. It is an
inverse problem without the standard uniqueness guarantee. To make complete
theoretical analyses and devise efficient algorithms to recover the signal is
sophisticated. In this paper, we come up with a model called \textit{phase
retrieval with background information} which recovers the signal with the known
background information from the intensity of their combinational Fourier
transform spectrum. We prove that the uniqueness of phase retrieval can be
guaranteed even considering those trivial solutions when the background
information is sufficient. Under this condition, we construct a loss function
and utilize the projected gradient descent method to search for the ground
truth. We prove that the stationary point is the global optimum with
probability 1. Numerical simulations demonstrate the projected gradient descent
method performs well both for 1-D and 2-D signals. Furthermore, this method is
quite robust to the Gaussian noise and the bias of the background information
Multiple Scattering Media Imaging via End-to-End Neural Network
Recovering the image of an object from its phaseless speckle pattern is
difficult. Let alone the transmission matrix is unknown in multiple scattering
media imaging. Double phase retrieval is a recently proposed efficient method
which recovers the unknown object from its phaseless measurements by two steps
with phase retrieval.
In this paper, we combine the two steps in double phase retrieval and
construct an end-to-end neural network called TCNN(Transforming Convolutional
Neural Network) which directly learns the relationship between the phaseless
measurements and the object. TCNN contains a special layer called transform
layer which aims to be a bridge between different transform domains. Tested by
the empirical data provided in\cite{Metzler2017Coherent}, images can be
recovered by TCNN with comparable quality compared with state-of-the-art
methods. Not only the transmission matrix needn't to be calculated but also the
time to recover the object can be hugely reduced once the parameters of TCNN
are stable
Phase Retrieval via Sparse Wirtinger Flow
Phase retrieval(PR) problem is a kind of ill-condition inverse problem which
can be found in various of applications. Utilizing the sparse priority, an
algorithm called SWF(Sparse Wirtinger Flow) is proposed in this paper to deal
with sparse PR problem based on the Wirtinger flow method. SWF firstly recovers
the support of the signal and then updates the evaluation by hard thresholding
method with an elaborate initialization. Theoretical analyses show that SWF has
a geometric convergence for any sparse length signal with the sampling
complexity . To get accuracy, the
computational complexity of SWF is
.
Numerical tests also demonstrate that SWF performs better than
state-of-the-art methods especially when we have no priori knowledge about
sparsity . Moreover, SWF is also robust to the nois
A New Concept of Deep Reinforcement Learning based Augmented General Sequence Tagging System
In this paper, a new deep reinforcement learning based augmented general
sequence tagging system is proposed. The new system contains two parts: a deep
neural network (DNN) based sequence tagging model and a deep reinforcement
learning (DRL) based augmented tagger. The augmented tagger helps improve
system performance by modeling the data with minority tags. The new system is
evaluated on SLU and NLU sequence tagging tasks using ATIS and CoNLL-2003
benchmark datasets, to demonstrate the new system's outstanding performance on
general tagging tasks. Evaluated by F1 scores, it shows that the new system
outperforms the current state-of-the-art model on ATIS dataset by 1.9% and that
on CoNLL-2003 dataset by 1.4%.Comment: Published at 2018 COLIN
The effect of hidden color channels on Nucleon-Nucleon interaction
This letter reports the nucleon-nucleon() interaction obtained from
multi-channel, including hidden color channels, coupling quark model
calculation. The results show that the hidden color channels coupling provides
the intermediate range attraction which is usually assumed to be due to
multi- or meson exchange and that the short and intermediate
range interaction can be described solely by the fundamental quark-gluon
degree of freedom of QCD.Comment: 5 pages, 5 figure
A Neural Transition-based Model for Nested Mention Recognition
It is common that entity mentions can contain other mentions recursively.
This paper introduces a scalable transition-based method to model the nested
structure of mentions. We first map a sentence with nested mentions to a
designated forest where each mention corresponds to a constituent of the
forest. Our shift-reduce based system then learns to construct the forest
structure in a bottom-up manner through an action sequence whose maximal length
is guaranteed to be three times of the sentence length. Based on Stack-LSTM
which is employed to efficiently and effectively represent the states of the
system in a continuous space, our system is further incorporated with a
character-based component to capture letter-level patterns. Our model achieves
the state-of-the-art results on ACE datasets, showing its effectiveness in
detecting nested mentions.Comment: EMNLP 201
Possible -like dibaryon states with heavy quarks
Possible -like dibaryon states and
are investigated within the framework of quark
delocalization color screening model. The results show that the interaction
between two 's is repulsive, so it cannot be bound state by
itself. However, the strong attraction in and
channels and the strong channel coupling, due to
the central interaction of one-gluon-exchange and one-pion-exchange, among
, and
push the energy of system below the threshold of
by MeV. The corresponding system
has the similar properties as that of
system, and a bound state is also possible in
system.Comment: 6 pages, 4 figures, 3 table
Investigating the excited states through and decay channels
Inspired by the five newly observed states by the LHCb
detector, we study the states as the wave molecular
pentaquarks with , , , and
by solving the RGM equation in the framework of chiral quark
model. Both the energies and the decay widths are obtained in this work. Our
results suggest that can be explained as an wave
resonance state of with , and the decay channels
are the wave and . Other reported
states cannot be obtained in our present calculation. Another
state with much higher mass 3533 MeV with
is also obtained. In addition, the calculation is
extended to the states, similar results as that of
are obtained.Comment: 6 pages, 2 figure
Theoretical study of a resonance in partial wave of nucleon-nucleon scattering
Inspired by the recent results of the WASA-at-COSY Collaboration, in which
they found a resonance pole in the coupled - partial
waves as expected from the resonance hypothesis, we calculated the
resonance structure in the coupled - partial wave phase
shifts of nucleon-nucleon scattering in the framework of two constituent quark
models: the quark delocalization color screening model and the chiral quark
model. Our results show that there is a resonance in
the coupled and partial waves in both of
these two models, which is in accordance with the expectation from the
resonance structure. The resonance shape in the partial wave
is remarkable, whereas in the phase shifts there is a small
rise around the resonance energy. This result is in agreement with the recent
experimental observations of WASA-at-COSY Collaboration.Comment: 5 pages, 3 figure
Further study of the dibaryon within constituent quark models
Inspired by the discovery of the dibaryon and the experimental search
of dibaryon with the STAR data, we study the strange dibaryon
further in the framework of quark delocalization color screening
model and chiral quark model. We have shown is a narrow resonance in
D-wave scattering before. However, the - scattering
data analysis is quite complicated. Here we calculate the low-energy
scattering phase shifts, scattering length, effective range and binding energy
to provide another approach of STAR data analysis. Our results show there
exists an "bound" state, which can be observed by the -
correlation analysis with RHIC and LHC data, or by the new developed automatic
scanning system at J-PARC. Besides, we also find that the hidden color
channel-coupling is important for the system to develop
intermediate-range attraction.Comment: 7 pages, 2 figure
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