6 research outputs found
Federated Meta-Learning for Few-Shot Fault Diagnosis with Representation Encoding
Deep learning-based fault diagnosis (FD) approaches require a large amount of
training data, which are difficult to obtain since they are located across
different entities. Federated learning (FL) enables multiple clients to
collaboratively train a shared model with data privacy guaranteed. However, the
domain discrepancy and data scarcity problems among clients deteriorate the
performance of the global FL model. To tackle these issues, we propose a novel
framework called representation encoding-based federated meta-learning (REFML)
for few-shot FD. First, a novel training strategy based on representation
encoding and meta-learning is developed. It harnesses the inherent
heterogeneity among training clients, effectively transforming it into an
advantage for out-of-distribution generalization on unseen working conditions
or equipment types. Additionally, an adaptive interpolation method that
calculates the optimal combination of local and global models as the
initialization of local training is proposed. This helps to further utilize
local information to mitigate the negative effects of domain discrepancy. As a
result, high diagnostic accuracy can be achieved on unseen working conditions
or equipment types with limited training data. Compared with the
state-of-the-art methods, such as FedProx, the proposed REFML framework
achieves an increase in accuracy by 2.17%-6.50% when tested on unseen working
conditions of the same equipment type and 13.44%-18.33% when tested on totally
unseen equipment types, respectively
Plasma LncRNA-ATB, a Potential Biomarker for Diagnosis of Patients with Coal Workers’ Pneumoconiosis: A Case-Control Study
LncRNA-ATB (lncRNA was activated by transforming growth factor-β) has been reported to be involved in specific physiological and pathological processes in human diseases, and could serve as biomarkers for cancers. However, the role of lncRNA-ATB in coal workers’ pneumoconiosis (CWP) is still unknown. This study aimed to investigate the association between lncRNA-ATB and CWP. Quantitative real-time polymerase chain reaction was performed to detect plasma lncRNA-ATB expression in 137 CWP patients, 72 healthy coal miners and 168 healthy controls. LncRNA-ATB was significantly upregulated in CWP (p < 0.05). Compared with the healthy controls and healthy coal miners, the odds ratios (ORs) (95% confidence interval (CI)) for CWP were 2.57 (1.52–4.33) and 2.17 (1.04–4.53), respectively. LncRNA-ATB was positively associated with transforming growth factor-β1 (TGF-β1) (r = 0.30, p = 0.003) and negative correlated with vital capacity (VC) (r = −0.18, p = 0.033) and forced vital capacity (FVC) (r = −0.18, p = 0.046) in CWP patients. Compared with healthy controls, the area under the curve (AUC) was 0.84, resulting in a 71.17% sensitivity and 88.14% specificity. When compared with healthy coal miners, the AUC was 0.83, the sensitivity and specificity were 70.07% and 86.36%, respectively. LncRNA-ATB expression is commonly increased in CWP and significantly correlates with the TGF-β1 in CWP patients. Furthermore, elevated lncRNA-ATB was associated with CWP risk and may serve as a potential biomarker for CWP
In Situ Diagnosis of Wire Bonding Faults for Multichip IGBT Modules Based on the Crosstalk Effect
Introducing bond wire diagnosis for multichip IGBT modules is key to the health monitoring of modular multilevel converters (MMCs), which allows for improved field robustness, reliability, and reduced maintenance cost. This paper leverages the crosstalk phenomenon during switching transitions to detect the chip open-circuit faults caused by the bond wire lift-off using typical half-bridge IGBT modules in a multichip-parallel configuration. The cycle-controlled, non-intrusive measurement is conducted under normal operation, when the device under test is at off-state and its complementary switch is during switching transitions. Two specialized health sensitive parameters arising from the dynamic gate loop waveforms are identified and evaluated, including 1) the gate voltage VGE(t3) when the declining collector voltage reaches zero, and 2) the negative peak gate voltage VGE(t4). The sensitivity and stability of these two parameters are compared through theoretical analysis, circuit simulation and practical verification. The results show that VGE(t4) is more suitable for online monitoring, while VGE(t3) is more sensitive than VGE(t4). With managed complexity in gate drives, this proposed health awareness approach is feasible in the submodules of MMC applications, but it can also be used in other power converter topologies incorporating the half-bridge structure
Higher intracranial arterial pulsatility is associated with presumed imaging markers of the glymphatic system: An explorative study
Background: Arterial pulsation has been suggested as a key driver of paravascular cerebrospinal fluid flow, which is the foundation of glymphatic clearance. However, whether intracranial arterial pulsatility is associated with glymphatic markers in humans has not yet been studied. Methods: Seventy-three community participants were enrolled in the study. 4D phase-contrast magnetic resonance imaging (MRI) was used to quantify the hemodynamic parameters including flow pulsatility index (PIflow) and area pulsatility index (PIarea) from 13 major intracerebral arterial segments. Three presumed neuroimaging markers of the glymphatic system were measured: including dilation of perivascular space (PVS), diffusivity along the perivascular space (ALPS), and volume fraction of free water (FW) in white matter. We explored the relationships between PIarea, PIflow, and the presumed glymphatic markers, controlling for related covariates. Results: PIflow in the internal carotid artery (ICA) C2 segment (OR, 1.05; 95 % CI, 1.01–1.10, per 0.01 increase in PI) and C4 segment (OR, 1.05; 95 % CI, 1.01–1.09) was positively associated with the dilation of basal ganglia PVS, and PIflow in the ICA C4 segment (OR, 1.06, 95 % CI, 1.02–1.10) was correlated with the dilation of PVS in the white matter. ALPS was associated with PIflow in the basilar artery (β, -0.273, p, 0.046) and PIarea in the ICA C2 (β, -0.239, p, 0.041) and C7 segments (β, -0.238, p, 0.037). Conclusions: : Intracranial arterial pulsatility was associated with presumed neuroimaging markers of the glymphatic system, but the results were not consistent across different markers. Further studies are warranted to confirm these findings
Inverse Association between Ambient Sulfur Dioxide Exposure and Semen Quality in Wuhan, China
Evidence concerning the association
between ambient gaseous air
pollutant exposures and semen quality is sparse, and findings in previous
studies remain largely inconsistent. We enrolled 1759 men and performed
2184 semen examinations at a large reproductive medical center in
Wuhan, China, between 2013 and 2015. Inverse distance weighting interpolation
was performed to estimate individual exposures to SO<sub>2</sub>,
NO<sub>2</sub>, CO, and O<sub>3</sub> during the entire period (lag
0–90 days) and key periods (lag 0–9, 10–14, 70–90
days) of sperm development. Linear mixed models were used to analyze
exposure–response relationships. SO<sub>2</sub> exposure with
0–90 days lag was significantly associated with monotonically
decreased sperm concentration (β for each interquartile range
increase of exposure: −0.14; 95% CI: −0.23, −0.05),
sperm count (−0.21; −0.30, −0.12) and total motile
sperm count (−0.16; −0.25, −0.08). Significant
associations were observed for total and progressive motility only
when SO<sub>2</sub> exposure was at the highest quintile (all <i>P</i><sub>trend</sub> < 0.05). Similar trends were observed
for SO<sub>2</sub> exposure with 70–90 days lag. NO<sub>2</sub>, CO, or O<sub>3</sub> exposure was not significantly associated
with semen quality. Our results suggest that ambient SO<sub>2</sub> exposure adversely affects semen quality and highlight the potential
to improve semen quality by reducing ambient SO<sub>2</sub> exposure
during early stages of sperm development