950 research outputs found
Enhancing Control Performance through ESN-Based Model Compensation in MPC for Dynamic Systems
Deriving precise system dynamic models through traditional numerical methods
is often a challenging endeavor. The performance of Model Predictive Control is
heavily contingent on the accuracy of the system dynamic model. Consequently,
this study employs Echo State Networks to acquire knowledge of the unmodeled
dynamic characteristics inherent in the system. This information is then
integrated with the nominal model, functioning as a form of model compensation.
The present paper introduces a control framework that combines ESN with MPC. By
perpetually assimilating the disparities between the nominal and real models,
control performance experiences augmentation. In a demonstrative example, a
second order dynamic system is subjected to simulation. The outcomes
conclusively evince that ESNbased MPC adeptly assimilates unmodeled dynamic
attributes, thereby elevating the system control proficiency.Comment: 5 pages,3 figures,conferenc
When Social Influence Meets Item Inference
Research issues and data mining techniques for product recommendation and
viral marketing have been widely studied. Existing works on seed selection in
social networks do not take into account the effect of product recommendations
in e-commerce stores. In this paper, we investigate the seed selection problem
for viral marketing that considers both effects of social influence and item
inference (for product recommendation). We develop a new model, Social Item
Graph (SIG), that captures both effects in form of hyperedges. Accordingly, we
formulate a seed selection problem, called Social Item Maximization Problem
(SIMP), and prove the hardness of SIMP. We design an efficient algorithm with
performance guarantee, called Hyperedge-Aware Greedy (HAG), for SIMP and
develop a new index structure, called SIG-index, to accelerate the computation
of diffusion process in HAG. Moreover, to construct realistic SIG models for
SIMP, we develop a statistical inference based framework to learn the weights
of hyperedges from data. Finally, we perform a comprehensive evaluation on our
proposals with various baselines. Experimental result validates our ideas and
demonstrates the effectiveness and efficiency of the proposed model and
algorithms over baselines.Comment: 12 page
Improving Image Captioning with Conditional Generative Adversarial Nets
In this paper, we propose a novel
conditional-generative-adversarial-nets-based image captioning framework as an
extension of traditional reinforcement-learning (RL)-based encoder-decoder
architecture. To deal with the inconsistent evaluation problem among different
objective language metrics, we are motivated to design some "discriminator"
networks to automatically and progressively determine whether generated caption
is human described or machine generated. Two kinds of discriminator
architectures (CNN and RNN-based structures) are introduced since each has its
own advantages. The proposed algorithm is generic so that it can enhance any
existing RL-based image captioning framework and we show that the conventional
RL training method is just a special case of our approach. Empirically, we show
consistent improvements over all language evaluation metrics for different
state-of-the-art image captioning models. In addition, the well-trained
discriminators can also be viewed as objective image captioning evaluatorsComment: 12 pages; 33 figures; 36 refenences; Accepted by AAAI201
Image to Multi-Modal Retrieval for Industrial Scenarios
We formally define a novel valuable information retrieval task:
image-to-multi-modal-retrieval (IMMR), where the query is an image and the doc
is an entity with both image and textual description. IMMR task is valuable in
various industrial application. We analyze three key challenges for IMMR: 1)
skewed data and noisy label in metric learning, 2) multi-modality fusion, 3)
effective and efficient training in large-scale industrial scenario. To tackle
the above challenges, we propose a novel framework for IMMR task. Our framework
consists of three components: 1) a novel data governance scheme coupled with a
large-scale classification-based learning paradigm. 2) model architecture
specially designed for multimodal learning, where the proposed concept-aware
modality fusion module adaptively fuse image and text modality. 3. a hybrid
parallel training approach for tackling large-scale training in industrial
scenario. The proposed framework achieves SOTA performance on public datasets
and has been deployed in a real-world industrial search system, leading to
significant improvements in click-through rate and deal number. Code and data
will be made publicly available
Relationship between developmental canal stenosis and surgical results of anterior decompression and fusion in patients with cervical spondylotic myelopathy
Identification of Blue Horizontal-Branch Stars From LAMOST DR5
We construct a new catalog of the blue horizontal-branch (BHB) stars from the
Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) DR5 dataset,
which contains 5355+81 BHB stars at high Galactic latitude
((). We combine the spectral line indices with a set of
Balmer line profile selection criteria to identify the BHB stars. During the
selection process, we use the line index of \ion{Ca}{2}\,K to exclude the
metal-rich A-type dwarfs. We obtain their atmospheric parameters by
cross-matching our BHB stars with the catalog provided by \citet{Xiang2022}.
The results show that our sample is consistent with the theoretical -log\, evolutionary tracks of the BHB stars, indicating that our method
is robust for identifying BHB stars from the LAMOST spectra. Their spatial
distribution indicates that most of our BHB stars are located in the inner halo
or the disk of the Milky Way. Combined with other BHB samples from the
literature, the BHB stars can cover a large Galactic volume, which makes it a
better probe for studying the kinematics, dynamics, and structural
characteristics of the Milky Way.Comment: accepted by ApJS.15 pages, 18 figure
The Clumpy Structure Of Five Star-bursting Dwarf Galaxies In The MaNGA Survey
The star-forming clumps in star-bursting dwarf galaxies provide valuable
insights into the understanding of the evolution of dwarf galaxies. In this
paper, we focus on five star-bursting dwarf galaxies featuring off-centered
clumps in the Mapping Nearby Galaxies at Apache Point Observatory (MaNGA)
survey. Using the stellar population synthesis software FADO, we obtain the
spatially-resolved distribution of the star formation history, which allows us
to construct the -band images of the five galaxies at different ages. These
images can help us to probe the evolution of the morphological structures of
these galaxies. While images of stellar population older than 1 Gyr are
typically smooth, images of stellar population younger than 1 Gyr reveal
significant clumps, including multiple clumps which appear at different
locations and even different ages. To study the evolutionary connections of
these five galaxies to other dwarf galaxies before their star-forming clumps
appear, we construct the images of the stellar populations older than three age
nodes, and define them to be the images of the "host" galaxies. We find that
the properties such as the central surface brightness and the effective radii
of the hosts of the five galaxies are in between those of dwarf ellipticals
(dEs) and dwarf irregulars (dIrrs), with two clearly more similar to dEs and
one more similar to dIrrs. Among the five galaxies, 8257-3704 is particularly
interesting, as it shows a previous starburst event that is not quite visible
from its image, but only visible from images of the stellar population at
a few hundred million years. The star-forming clump associated with this event
may have appeared at around 600 Myr and disappeared at around 40 Myr.Comment: 21 pages, 16 figures, accepted for publication in RA
Lifestyle and metabolic factors for nonalcoholic fatty liver disease:Mendelian randomization study
The risk factors for nonalcoholic fatty liver disease (NAFLD) have not been clearly identified. We conducted a Mendelian randomization (MR) study to explore this. Independent genetic variants strongly associated with 5 lifestyle and 9 metabolic factors were selected as instrumental variables from corresponding genome-wide association studies (GWASs). Summary-level data for NAFLD were obtained from a GWAS meta-analysis of 8434 cases and 770,180 non-cases (discovery dataset) and another GWAS meta-analysis of 1483 cases and 17,781 non-cases (replication dataset). Univariable and multivariable MR analyses were performed. There were associations with NAFLD for lifetime smoking index (odds ratio (OR) 1.59, 95% confidence interval (CI) 1.31-1.93 per SD-increase), body mass index (BMI, OR 1.33, 95% CI 1.23-1.43 per SD-increase), waist circumference (OR 1.82; 95% CI 1.48-2.24 per SD-increase), type 2 diabetes (OR 1.21, 95% CI 1.15-1.27 per unit increase in log-transformed odds), systolic blood pressure (OR 1.17; 95% CI 1.07-1.26 per 10 mmHg increase), high-density lipoprotein cholesterol (OR 0.84, 95% CI 0.77-0.90 per SD-increase), and triglycerides (OR 1.23, 95% CI 1.15-1.33 per SD-increase). The associations for type 2 diabetes, systolic blood pressure, triglycerides, but not for high-density lipoprotein cholesterol remained strong after adjusting for genetically-predicted BMI. Genetic liability to type 2 diabetes mediated 51.4% (95% CI 13.4-89.3%) of the BMI-effects on NAFLD risk. There were suggestive inverse associations of genetically-predicted alcohol, coffee, and caffeine consumption, and vigorous physical activity with NAFLD risk. This study identified several lifestyle and metabolic factors that may be causally implicated in NAFLD
- …