1,635 research outputs found
Online Bearing Remaining Useful Life Prediction Based on a Novel Degradation Indicator and Convolutional Neural Networks
In industrial applications, nearly half the failures of motors are caused by
the degradation of rolling element bearings (REBs). Therefore, accurately
estimating the remaining useful life (RUL) for REBs are of crucial importance
to ensure the reliability and safety of mechanical systems. To tackle this
challenge, model-based approaches are often limited by the complexity of
mathematical modeling. Conventional data-driven approaches, on the other hand,
require massive efforts to extract the degradation features and construct
health index. In this paper, a novel online data-driven framework is proposed
to exploit the adoption of deep convolutional neural networks (CNN) in
predicting the RUL of bearings. More concretely, the raw vibrations of training
bearings are first processed using the Hilbert-Huang transform (HHT) and a
novel nonlinear degradation indicator is constructed as the label for learning.
The CNN is then employed to identify the hidden pattern between the extracted
degradation indicator and the vibration of training bearings, which makes it
possible to estimate the degradation of the test bearings automatically.
Finally, testing bearings' RULs are predicted by using a -support
vector regression model. The superior performance of the proposed RUL
estimation framework, compared with the state-of-the-art approaches, is
demonstrated through the experimental results. The generality of the proposed
CNN model is also validated by transferring to bearings undergoing different
operating conditions
Towards Trustworthy Dataset Distillation
Efficiency and trustworthiness are two eternal pursuits when applying deep
learning in real-world applications. With regard to efficiency, dataset
distillation (DD) endeavors to reduce training costs by distilling the large
dataset into a tiny synthetic dataset. However, existing methods merely
concentrate on in-distribution (InD) classification in a closed-world setting,
disregarding out-of-distribution (OOD) samples. On the other hand, OOD
detection aims to enhance models' trustworthiness, which is always
inefficiently achieved in full-data settings. For the first time, we
simultaneously consider both issues and propose a novel paradigm called
Trustworthy Dataset Distillation (TrustDD). By distilling both InD samples and
outliers, the condensed datasets are capable to train models competent in both
InD classification and OOD detection. To alleviate the requirement of real
outlier data and make OOD detection more practical, we further propose to
corrupt InD samples to generate pseudo-outliers and introduce Pseudo-Outlier
Exposure (POE). Comprehensive experiments on various settings demonstrate the
effectiveness of TrustDD, and the proposed POE surpasses state-of-the-art
method Outlier Exposure (OE). Compared with the preceding DD, TrustDD is more
trustworthy and applicable to real open-world scenarios. Our code will be
publicly available.Comment: 20 pages, 20 figure
25-hydroxyvitamin D levels in children of different ages and with varying degrees of Helicobacter pylori infection and immunological features
BackgroundHelicobacter pylori (HP) is a major cause of upper digestive tract diseases. However, the relationship between HP infection and 25-hydroxyvitamin D [25(OH)D] levels in children has not been fully elucidated. This study investigated the levels of 25(OH)D in children of different ages and with varying degrees of HP infection and immunological features as well as the correlations between 25(OH)D levels in children infected with HP and their ages and degrees of infection.Materials and methodsNinety-four children who underwent upper digestive endoscopy were divided into an HP-positive group without peptic ulcers (Group A), an HP-positive group with peptic ulcers (Group B) and an HP-negative control group (Group C). The serum levels of 25(OH)D and immunoglobulin and the percentages of lymphocyte subsets were determined. HP colonization, the degree of inflammation, and the degree of activity were further evaluated by HE staining and immunohistochemical staining in gastric mucosal biopsy.ResultsThe 25(OH)D level of the HP-positive groups (50.93 ± 16.51 nmol/L) was significantly lower than that of the HP-negative group (62.89 ± 19.18 nmol/L). The 25(OH)D level of Group B (47.79 ± 14.79 nmol/L) was lower than that of Group A (51.53 ± 17.05 nmol/L) and was significantly lower than that of Group C (62.89 ± 19.18 nmol/L). The 25(OH)D level decreased with increasing age, and there was a significant difference between Group C subjects who were ≤5 years old and those who were aged 6–9 years and ≥10 years. The 25(OH)D level was negatively correlated with HP colonization (r = −0.411, P < 0.01) and the degree of inflammation (r = −0.456, P < 0.01). The percentages of lymphocyte subsets and immunoglobulin levels among Groups A, B and C were not significantly different.ConclusionsThe 25(OH)D level was negatively correlated with HP colonization and the degree of inflammation. As the age of the children increased, the level of 25(OH)D decreased, and the susceptibility to HP infection increased
Construction and systematic evaluation of a machine learning-based cuproptosis-related lncRNA score signature to predict the response to immunotherapy in hepatocellular carcinoma
IntroductionHepatocellular carcinoma (HCC) is a common malignant cancer with a poor prognosis. Cuproptosis and associated lncRNAs are connected with cancer progression. However, the information on the prognostic value of cuproptosis-related lncRNAs is still limited in HCC.MethodsWe isolated the transcriptome and clinical information of HCC from TCGA and ICGC databases. Ten cuproptosis-related genes were obtained and related lncRNAs were correlated by Pearson’s correlation. By performing lasso regression, we created a cuproptosis-related lncRNA prognostic model based on the cuproptosis-related lncRNA score (CLS). Comprehensive analyses were performed, including the fields of function, immunity, mutation and clinical application, by various R packages.ResultsTen cuproptosis-related genes were selected, and 13 correlated prognostic lncRNAs were collected for model construction. CLS was positively or negatively correlated with cancer-related pathways. In addition, cell cycle and immune related pathways were enriched. By performing tumor microenvironment (TME) analysis, we determined that T-cells were activated. High CLS had more tumor characteristics and may lead to higher invasiveness and treatment resistance. Three genes (TP53, CSMD1 and RB1) were found in high CLS samples with more mutational frequency. More amplification and deletion were detected in high CLS samples. In clinical application, a CLS-based nomogram was constructed. 5-Fluorouracil, gemcitabine and doxorubicin had better sensitivity in patients with high CLS. However, patients with low CLS had better immunotherapeutic sensitivity.ConclusionWe created a prognostic CLS signature by machine learning, and we comprehensively analyzed the signature in the fields of function, immunity, mutation and clinical application
Entanglement Structure: Entanglement Partitioning in Multipartite Systems and Its Experimental Detection Using Optimizable Witnesses
Creating large-scale entanglement lies at the heart of many quantum
information processing protocols and the investigation of fundamental physics.
For multipartite quantum systems, it is crucial to identify not only the
presence of entanglement but also its detailed structure. This is because in a
generic experimental situation with sufficiently many subsystems involved, the
production of so-called genuine multipartite entanglement remains a formidable
challenge. Consequently, focusing exclusively on the identification of this
strongest type of entanglement may result in an all or nothing situation where
some inherently quantum aspects of the resource are overlooked. On the
contrary, even if the system is not genuinely multipartite entangled, there may
still be many-body entanglement present in the system. An identification of the
entanglement structure may thus provide us with a hint about where
imperfections in the setup may occur, as well as where we can identify groups
of subsystems that can still exhibit strong quantum-information-processing
capabilities. However, there is no known efficient methods to identify the
underlying entanglement structure. Here, we propose two complementary families
of witnesses for the identification of such structures. They are based on the
detection of entanglement intactness and entanglement depth, each requires only
the implementation of solely two local measurements. Our method is also robust
against noises and other imperfections, as reflected by our experimental
implementation of these tools to verify the entanglement structure of five
different eight-photon entangled states. We demonstrate how their entanglement
structure can be precisely and systematically inferred from the experimental
data. In achieving this goal, we also illustrate how the same set of data can
be classically postprocessed to learn the most about the measured system.Comment: 21 pages, 13 figure
Converse Flexoelectricity of Low-Dimensional Bismuth Selenite (Bi2Se3) Revealed by Piezoresponse Force Microscopy (PFM)
Many kinds of two-dimensional (2D) van der Waals (vdW) have been demonstrated
to exhibit electromechanical coupling effects, which makes them promising
candidates for next-generation devices, such as piezotronics and
nanogenerators. Recently, flexoelectricity was found to account for the
out-of-plane electromechanical coupling in many 2D transition metal
dichalcogenides (TMDs) who only exhibit in-plane piezoelectricity. However, low
dimensional vdW three-dimensional (3D) topological insulators (TIs) have been
overlooked regarding their electromechanical properties. In this study, for the
first time, we experimentally investigate the electromechanical coupling of low
dimensional 3D TIs with a centrosymmetric crystal structure, where a binary
compound, bismuth selenite (Bi2Se3), is taken as an example. The results of
piezoresponse force microscope (PFM) tests on the Bi2Se3 nanoflakes show that
the material exhibits both out-of-plane and in-plane electromechanical
responses. The Bi2Se3 nanoflake with a thickness of 37 nm possesses an
effective out-of-plane piezoelectric coefficient of ~0.65 pm V-1. With careful
analyses, the electromechanical responses are verified to arise from the
converse flexoelectricity. The measured effective out-of-plane piezoelectric
coefficient is mainly contributed by flexoelectric coefficient, {\mu}_39, which
is estimated to be approximately 0.13 nC m-1. However, it is rather difficult
to obtain the in-plane component of the flexoelectric tensor from the in-plane
PFM measurements since the direction of the in-plane stress is always not
normal to the AFM cantilever axis. The results provide useful guidance for
understanding the flexoelectric effect of low dimensional vdW materials with
centrosymmetric crystal structures. Moreover, the work can pave to way to
explore the electromechanical devices based on the flexoelectricity of vdW TIs.Comment: 6 figure
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