187 research outputs found
An Accelerated Block Proximal Framework with Adaptive Momentum for Nonconvex and Nonsmooth Optimization
We propose an accelerated block proximal linear framework with adaptive
momentum (ABPL) for nonconvex and nonsmooth optimization. We analyze the
potential causes of the extrapolation step failing in some algorithms, and
resolve this issue by enhancing the comparison process that evaluates the
trade-off between the proximal gradient step and the linear extrapolation step
in our algorithm. Furthermore, we extends our algorithm to any scenario
involving updating block variables with positive integers, allowing each cycle
to randomly shuffle the update order of the variable blocks. Additionally,
under mild assumptions, we prove that ABPL can monotonically decrease the
function value without strictly restricting the extrapolation parameters and
step size, demonstrates the viability and effectiveness of updating these
blocks in a random order, and we also more obviously and intuitively
demonstrate that the derivative set of the sequence generated by our algorithm
is a critical point set. Moreover, we demonstrate the global convergence as
well as the linear and sublinear convergence rates of our algorithm by
utilizing the Kurdyka-Lojasiewicz (K{\L}) condition. To enhance the
effectiveness and flexibility of our algorithm, we also expand the study to the
imprecise version of our algorithm and construct an adaptive extrapolation
parameter strategy, which improving its overall performance. We apply our
algorithm to multiple non-negative matrix factorization with the norm,
nonnegative tensor decomposition with the norm, and perform extensive
numerical experiments to validate its effectiveness and efficiency
Globally Convergent Accelerated Algorithms for Multilinear Sparse Logistic Regression with -constraints
Tensor data represents a multidimensional array. Regression methods based on
low-rank tensor decomposition leverage structural information to reduce the
parameter count. Multilinear logistic regression serves as a powerful tool for
the analysis of multidimensional data. To improve its efficacy and
interpretability, we present a Multilinear Sparse Logistic Regression model
with -constraints (-MLSR). In contrast to the -norm and
-norm, the -norm constraint is better suited for feature
selection. However, due to its nonconvex and nonsmooth properties, solving it
is challenging and convergence guarantees are lacking. Additionally, the
multilinear operation in -MLSR also brings non-convexity. To tackle
these challenges, we propose an Accelerated Proximal Alternating Linearized
Minimization with Adaptive Momentum (APALM) method to solve the
-MLSR model. We provide a proof that APALM can ensure the
convergence of the objective function of -MLSR. We also demonstrate
that APALM is globally convergent to a first-order critical point as well
as establish convergence rate by using the Kurdyka-Lojasiewicz property.
Empirical results obtained from synthetic and real-world datasets validate the
superior performance of our algorithm in terms of both accuracy and speed
compared to other state-of-the-art methods.Comment: arXiv admin note: text overlap with arXiv:2308.1212
Weighted Sparse Partial Least Squares for Joint Sample and Feature Selection
Sparse Partial Least Squares (sPLS) is a common dimensionality reduction
technique for data fusion, which projects data samples from two views by
seeking linear combinations with a small number of variables with the maximum
variance. However, sPLS extracts the combinations between two data sets with
all data samples so that it cannot detect latent subsets of samples. To extend
the application of sPLS by identifying a specific subset of samples and remove
outliers, we propose an -norm constrained weighted sparse
PLS (-wsPLS) method for joint sample and feature selection,
where the -norm constrains are used to select a subset of
samples. We prove that the -norm constrains have the
Kurdyka-\L{ojasiewicz}~property so that a globally convergent algorithm is
developed to solve it. Moreover, multi-view data with a same set of samples can
be available in various real problems. To this end, we extend the
-wsPLS model and propose two multi-view wsPLS models for
multi-view data fusion. We develop an efficient iterative algorithm for each
multi-view wsPLS model and show its convergence property. As well as numerical
and biomedical data experiments demonstrate the efficiency of the proposed
methods
Orthodontic mini-implants: A systematic review.
AbstractPurposeTo compile and analyze the literature regarding orthodontic mini-implants (MIs) placement, clinical applications, success rate, adverse effects and patients’ pain experience in clinical practice.MethodologyPublications about orthodontic MIs variables were systematically searched from PubMed, Science Direct, and Google Scholar Beta electronic data bases using “orthodontic in conjunction with implant, microimplant, screw, miniscrew, screw implant, mini-implant, and temporary anchorage” as keywords. Data from selected articles were extracted and compiled to produce a summarized report. ResultsSeveral areas are suitable for MI placement. However; the region between second premolar and first molar is the safest. The MI success rate ranges from 77.7% to 93.43%. The pain associated with MIs is far less than tooth extraction and significantly lower than patients’ expectation. Root resorption is among the adverse effects and gonial angle pattern influences the MI success rate. ConclusionMIs offer a wide range of clinical anchorage application due to their minimal anatomical location limitation. The success rate of MI is reliably high. The pain caused by orthodontics MI is significantly lower than patients’ expectation.  
Precise Facial Landmark Detection by Reference Heatmap Transformer
Most facial landmark detection methods predict landmarks by mapping the input
facial appearance features to landmark heatmaps and have achieved promising
results. However, when the face image is suffering from large poses, heavy
occlusions and complicated illuminations, they cannot learn discriminative
feature representations and effective facial shape constraints, nor can they
accurately predict the value of each element in the landmark heatmap, limiting
their detection accuracy. To address this problem, we propose a novel Reference
Heatmap Transformer (RHT) by introducing reference heatmap information for more
precise facial landmark detection. The proposed RHT consists of a Soft
Transformation Module (STM) and a Hard Transformation Module (HTM), which can
cooperate with each other to encourage the accurate transformation of the
reference heatmap information and facial shape constraints. Then, a Multi-Scale
Feature Fusion Module (MSFFM) is proposed to fuse the transformed heatmap
features and the semantic features learned from the original face images to
enhance feature representations for producing more accurate target heatmaps. To
the best of our knowledge, this is the first study to explore how to enhance
facial landmark detection by transforming the reference heatmap information.
The experimental results from challenging benchmark datasets demonstrate that
our proposed method outperforms the state-of-the-art methods in the literature.Comment: Accepted by IEEE Transactions on Image Processing, March 202
SDSS J013127.34032100.1: A newly discovered radio-loud quasar at with extremely high luminosity
Only very few z>5 quasars discovered to date are radio-loud, with a
radio-to-optical flux ratio (radio-loudness parameter) higher than 10. Here we
report the discovery of an optically luminous radio-loud quasar, SDSS
J013127.34-032100.1 (J0131-0321 in short), at z=5.18+-0.01 using the Lijiang
2.4m and Magellan telescopes. J0131-0321 has a spectral energy distribution
consistent with that of radio-loud quasars. With an i-band magnitude of 18.47
and radio flux density of 33 mJy, its radio-loudness parameter is ~100. The
optical and near-infrared spectra taken by Magellan enable us to estimate its
bolometric luminosity to be L_bol ~ 1.1E48 erg/s, approximately 4.5 times
greater than that of the most distant quasar known to date. The black hole mass
of J0131-0321 is estimated to be 2.7E9 solar masses, with an uncertainty up to
0.4 dex. Detailed physical properties of this high-redshift, radio-loud,
potentially super-Eddington quasar can be probed in the future with more
dedicated and intensive follow-up observations using multi-wavelength
facilities.Comment: 5 pages, 3 figures, accepted to ApJ
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