Structural damage detection based on cloud model and Dempster-Shafer evidence theory

Cloud model and D-S theory have been widely used in uncertainty reasoning. Meanwhile, modal strain energy and Inner Product Vector are also utilized as damage-sensitive features to detect structural damage. In this paper, a new structural damage identification approach is proposed based on Dempster-Shafer theory and cloud model. Cloud models were created to make uncertainty reasoning in damage structures by modal strain energy and the Inner Product Vector of acceleration. Then the results of the two methods were combined by using the Dempster-Shafer theory. Due to the classical D-S theory involves counter – intuitive behavious when the high conflicting evidences exists, the distance function was introduced to correct the conflict factor K and combine the evidences. Moreover, a model of simple beam was created to verify the feasibility and accuracy for the single-damage and the multiple-damage. The effects of noise on damage detection were investigated simultaneously. The results show that the method has strong anti-noise ability and high accuracy

Endoribonuclease YbeY Is Essential for RNA Processing and Virulence in Pseudomonas aeruginosa

Posttranscriptional regulation plays an essential role in the quick adaptation of pathogenic bacteria to host environments, and RNases play key roles in this process by modifying small RNAs and mRNAs. We find that the Pseudomonas aeruginosa endonuclease YbeY is required for rRNA processing and the bacterial virulence in a murine acute pneumonia model. Transcriptomic analyses reveal that knocking out the ybeY gene results in downregulation of oxidative stress response genes, including the catalase genes katA and katB Consistently, the ybeY mutant is more susceptible to H2O2 and neutrophil-mediated killing. Overexpression of katA restores the bacterial tolerance to H2O2 and neutrophil killing as well as virulence. We further find that the downregulation of the oxidative stress response genes is due to defective expression of the stationary-phase sigma factor RpoS. We demonstrate an autoregulatory mechanism of RpoS and find that ybeY mutation increases the level of a small RNA, ReaL, which directly represses the translation of rpoS through the 5' UTR of its mRNA and subsequently reduces the expression of the oxidative stress response genes. In vitro assays demonstrate direct degradation of ReaL by YbeY. Deletion of reaL or overexpression of rpoS in the ybeY mutant restores the bacterial tolerance to oxidative stress and the virulence. We also demonstrate that YbeZ binds to YbeY and is involved in the 16S rRNA processing and regulation of reaL and rpoS as well as the bacterial virulence. Overall, our results reveal pleiotropic roles of YbeY and the YbeY-mediated regulation of rpoS through ReaL.IMPORTANCE The increasing bacterial antibiotic resistance imposes a severe threat to human health. For the development of effective treatment and prevention strategies, it is critical to understand the mechanisms employed by bacteria to grow in the human body. Posttranscriptional regulation plays an important role in bacterial adaptation to environmental changes. RNases and small RNAs are key players in this regulation. In this study, we demonstrate critical roles of the RNase YbeY in the virulence of the pathogenic bacterium Pseudomonas aeruginosa We further identify the small RNA ReaL as the direct target of YbeY and elucidate the YbeY-regulated pathway on the expression of bacterial virulence factors. Our results shed light on the complex regulatory network of P. aeruginosa and indicate that inference with the YbeY-mediated regulatory pathway might be a valid strategy for the development of a novel treatment strategy.</p

Underwater Camera Calibration Based on Double Refraction

Underwater camera calibration plays a pivotal role in underwater positioning and underwater mapping reconstruction, making it crucial for achieving precise spatial measurements in underwater environments. To elevate measurement accuracy, we have refined the calibration methodology for underwater cameras. Firstly, we conducted an in-depth investigation into the intricate challenges posed by double refraction errors arising from light passing through water–glass–air interfaces. To address this issue, we established a double refraction model based on the actual underwater light paths, laying the groundwork for our calibration efforts. Furthermore, to tackle the problem of determining multiple camera parameters, we proposed a parameter optimization method based on genetic algorithms, capable of navigating the complex parameter space. Finally, compared with other algorithms, our method enables more precise determination of underwater camera parameters

PDMS/PVDF Electrospinning Membranes for Water-in-Oil Emulsion Separation and UV Protection

With industry development, the separation of oily wastewater is becoming more critical. Inspired by organisms such as lotus leaves, biomimetic superhydrophobic surfaces with micro-nano structures have shown great potential in this regard. In this work, PDMS/PVDF oil&ndash;water separation membranes with designed microstructures were prepared by electrospinning technology. The membrane-forming effect of electrospinning with different ratios of PDMS and PVDF was studied. The study found that membranes with high PDMS content were more likely to form microspheres, and PDMS tended to concentrate on the microspheres. The results also showed that the microspheres would bring better hydrophobicity to the membrane. When the ratio of PDMS to PVDF is 1:2, the membrane has a water contact angle of up to 150&deg; and an oil contact angle of 0&deg;. At this ratio, the separation efficiency of the membrane for the water-in-oil emulsion is 98.7%, and it can still maintain more than 98% after ten separation cycles, which is a good candidate for oil&ndash;water separation. Furthermore, microspheres enable the membrane to achieve macroscopic uniformity and microscopic phase separation so that the membranes have both good elongation and fracture strength. In addition, the PDMS/PVDF membranes also exhibit excellent UV resistance, and their UV protection factor is greater than 185, making them a potential UV protective material

Sliding Mode Motion Control for AUV with Dual-Observer Considering Thruster Uncertainty

In the motion control of AUVs, especially those driven by multiple thrusters, the thruster misalignment and thrust loss cause the actual force and moment applied to the AUV to deviate from that desired, making accurate and fast motion control difficult. This paper proposes a sliding mode control method with dual-observer estimation for the AUV 3D motion control problem in the presence of thruster misalignment uncertainty and thrust loss uncertainty. Firstly, this paper considers the force and moment deviation as disturbances that vary with the controller output, and proposes the TD disturbance observer to address the problem of deviation caused by uncertainty in thruster misalignment. Secondly, this paper introduces the dynamics equation of thrust loss and designs the gain disturbance observer to estimate the thrust loss uncertainty during AUV navigation. The designed controller, verified by simulation and field tests, ensures that the AUV maintains better motion control despite thruster misalignment and thrust loss

The Economic Recovery from Traffic Restriction Policies during the COVID-19 through the Perspective of Regional Differences and Sustainable Development: Based on Human Mobility Data in China

In the post-epidemic era, balancing epidemic prevention and control with sustainable economic development has become a serious challenge for all countries around the world. In China, a range of interventions include detection policies, clinical treatment policies, and most notably, traffic policies have been carried out for epidemic prevention and control. It has been widely confirmed that massive traffic restriction policies effectively brought the spread of the pandemic under control. However, restrictions on the use of transportation infrastructure undermine the smooth functioning of the economy. Particularly, China has a vast territory, with provinces differing in economic development, leading industries and transportation infrastructure; economic shock varies from region to region. In this case, targeted policies are the key to sustainable development. This paper sets forth advice for the Chinese government on its measures to boost the economy by analyzing regional differences in the impact of massive traffic restriction policies, based on large-scale human mobility data. After applying the Data Envelopment Analysis model, we classify Chinese provinces into different regions from the perspective of economic gradient, degree of internationalization and level of traffic convenience, respectively. Classification results are matched with the indicators of New Venues Created and the weekly Volumes of Visits to Venues from Baidu Maps. We find that the regional differences in the recovery of investment and consumption levels are striking. Based on the findings, we suggest that the government should adjust the intensity of traffic restrictions and economic stimulus policies dynamically according to regional differences to achieve sustainable economic development

Identification of a comprehensive alternative splicing function during epithelial-mesenchymal transition

Summary: Epithelial-to-mesenchymal transition (EMT) is the underlying mechanism for tumor metastasis and shows the metastatic potential of tumor cells. Although the transcriptional regulation of EMT has been well studied, the role of alternative splicing (AS) regulation in EMT remains largely uncharacterized. The rapid accumulation of RNA-seq datasets has provided the opportunities for developing computational methods to associate mRNA isoform variations with EMT. In this study, we propose regularization models to identify significant AS events during EMT. Our experimental results confirm that the predicted AS events are closely related to apoptosis, focal adhesion-invadopodium shift and tight junction formation that are essential during EMT. Therefore, our study highlights the broad role of posttranscriptional regulation during EMT and identifies key subsets of AS events serving as distinct regulatory nodes

Virtual Impedance Refined Inductor Current Observation and Current Sensorless Control for Grid-Connected Inverter

When facing the current sensor failures, the inverter system will be shut down or run in open-loop mode, and the controllability will be severely degraded. Therefore, the development of the current sensorless control strategy for the grid-connected inverter is worthy of academic attention. In order to solve this problem, a current observation method is proposed in this article, which is enhanced by the virtual impedance and operation data based error correction. The method combines the control scheme variables of dc side voltage and ac side grid voltage to observe the ac side inductor current. The output of current sensors can be replaced in the current closed-loop control, contributing to the current sensorless control. The research results show that the current observation method can effectively track the real-time current and the virtual impedance implementation ensures the accuracy of this current observation. Under the impedance refined current observations, dynamic variations in inductor current can be timely reflected, and the stable operation of the current sensorless closed-loop control can be ensured. Finally, the correctness and effectiveness of the proposed control strategy have been verified by MATLAB / Simulink simulation and experimental results.</p