344 research outputs found

    A Novel Method for Intelligent Single Fault Detection of Bearings Using SAE and Improved D–S Evidence Theory

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    In order to realize single fault detection (SFD) from the multi-fault coupling bearing data and further research on the multi-fault situation of bearings, this paper proposes a method based on features self-extraction of a Sparse Auto-Encoder (SAE) and results fusion of improved Dempster–Shafer evidence theory (D–S). Multi-fault signal compression features of bearings were extracted by SAE on multiple vibration sensors’ data. Data sets were constructed by the extracted compression features to train the Support Vector Machine (SVM) according to the rule of single fault detection (R-SFD) this paper proposed. Fault detection results were obtained by the improved D–S evidence theory, which was implemented via correcting the 0 factor in the Basic Probability Assignment (BPA) and modifying the evidence weight by Pearson Correlation Coefficient (PCC). Extensive evaluations of the proposed method on the experiment platform datasets showed that the proposed method could realize single fault detection from multi-fault bearings. Fault detection accuracy increases as the output feature dimension of SAE increases; when the feature dimension reached 200, the average detection accuracy of the three sensors for bearing inner, outer, and ball faults achieved 87.36%, 87.86% and 84.46%, respectively. The three types’ fault detection accuracy—reached to 99.12%, 99.33% and 98.46% by the improved Dempster–Shafer evidence theory (IDS) to fuse the sensors’ results—is respectively 0.38%, 2.06% and 0.76% higher than the traditional D–S evidence theory. That indicated the effectiveness of improving the D–S evidence theory by evidence weight calculation of PCC

    Quantitative analysis of Triassic-Jurassic pollen and spores for paleoenvironmental and paleoclimate reconstructions

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    The eco-group classification based on the growth-form of plants (Eco-Plant model) is widely used for extant, Cenozoic, Mesozoic, and Paleozoic palaeoenvironmental reconstructions. However, for most Mesozoic dispersed sporomorphs, the application of the Eco-Plant model is limited, because either their assignment to a specific eco-group remains uncertain or the botanical affinities to plant taxa are unclear. A new database Sporopollen (http://www.sporopollen.com) focused mainly on Mesozoic sporomorphs is created. Currently, it has collected 100,610 sporomorph pictures, 59, 498 plant pictures, 31, 922 sporomorph descriptions. At the same time, from 63, 035 references, it has collected 2, 215, 162 occurrences for both sporomorph and non-sporomorph fossils. The collected plant data include 32, 972 genera from 946 families. The collected sporomorph pictures include 5, 857 genera. With the help of the database, 861 dispersed Mesozoic sporomorph genera of Bryophytes, Pteridophytes, and Gymnosperms are reviewed by comparing the unique outline and structure/sculpture of the sporomorph wall with that of modern plants and in situ fossil plants. The results show that 474 of them can be linked to their closest parent plants and Eco-Plant model at family or order level, but 387 of them can not because of the lack of detailed ultrastructure descriptions. The use of a light microscope (LM) for determination is one of the main reasons that some dispersed sporomorphs cannot be linked precisely to their parent plants. The presented eco-groups for disperse Mesozoic sporomorphs provide the possibility to identify detailed vegetation and palaeoenvironmental change in the Mesozoic, especially in the context of climate change. A new interface (http://www.sporopollen.com/sporemesozoicsegs.php?opencode=paper1) was created based on the reviewed result to quickly link the dispersed sporomorphs to past vegetation patterns and climatic changes. Users can upload their data to the database and in return get quick results. It can automatically link all of the Mesozoic and Cenozoic sporomorphs to their possible parent plants at phylum, order, or family level. It can also automatically link all of the Triassic and Jurassic sporomorphs to the Eco-Plant model to assess the effect of humidity (EPH) and the effect of temperature (EPT). By using 30 sporomorph samples from a 10 m thick lignite bed from the Upper Triassic Haojiagou Formation (Rhaetian) as an example, the palaeovegetation and palaeoenvironment of a peat-forming wetland near the Triassic-Jurassic boundary are discussed with the help of the Eco-Plant model. The results show that the palynoflora contains both Eurasian and Gondwanan elements, and is dominated by the spores and pollen of Bennettitales, Corystospermales, Ginkgoales, and Gleicheniales. At the Triassic/Jurassic boundary (Hettangian), the palynoflora significantly changes as Cyatheales spores become the dominant elements. We analyse assemblages in terms of an Eco-Plant model, which assigns the parent plants of the palynomorphs into five groups based on humidity and four groups based on temperature, and uses multivariate statistical analyses to infer palaeoclimate and palaeoenvironmental conditions. Results suggest that the palaeoclimate of the Rhaetian was generally wet and subtropical with short seasonal drought periods. Our analysis shows that an Eco-Plant model may be a useful tool to reveal past vegetation patterns and climate changes, applicable to other Mesozoic assemblages

    X-efficiency versus rent seeking in Chinese banks: 1997-2006

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    This study demarcates cost-inefficiency in Chinese banks into X-inefficiency and rent-seeking-inefficiency. A protected banking market not only encourages weak management and X-inefficiency but also public ownership and state directed lending encourages moral hazard and bureaucratic rent seeking. This paper uses bootstrap non-parametric techniques to estimate measures of X-inefficiency and rent-seeking inefficiency for the 4 state owned banks and 10 joint-stock banks over the period 1997-2006. The paper adjusts for the quality of loans by treating NPLs as a negative output. The paper shows that Chinese banks have reduced cost inefficiency and reduced X-inefficiency at a faster rate than rent-seeking inefficiency

    Non-performing loans and productivity in Chinese banks: 1997-2006

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    This study examines the productivity growth of the nationwide banks of China over the ten years to 2006. Using a bootstrap method for the Malmquist index estimates of productivity growth are constructed with appropriate confidence intervals. The paper adjusts for the quality of the output by accounting for the non-performing loans on the balance sheets and test for the robustness of the results by examining alternative sets of outputs. The productivity growth of the state-owned banks is compared with the Joint-stock banks and it determinants evaluated. The paper finds that average productivity of the Chinese banks improved modestly over this period. Adjusting for the quality of loans, by treating NPLs as an undesirable output, the average productivity growth of the state-owned banks was zero or negative while productivity of the Joint-Stock banks was markedly higher

    Interaction of human mesenchymal stem cells with soft nanocomposite hydrogels based on polyethylene glycol and dendritic polyglycerol

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    Keeping the stemness of human mesenchymal stem cells (hMSCs) and their adipocyte differentiation potential is critical for clinical use. However, these features are lost on traditional substrates. hMSCs have often been studied on stiff materials whereas culturing hMSCs in their native niche increases their potential. Herein, a patterned hydrogel nanocomposite with the stiffness of liver tissues is obtained without any molding process. To investigate hMSCs' mechanoresponse to the material, the RGD spacing units and the stiffness of the hydrogels are dually tuned via the linker length. This work suggests that hMSCs' locomotion is influenced by the nature of the hydrogel layer (bulk or thin film). Contrary to on bulk surfaces, cell traction occurs during cell spreading on thin films. In addition, hMSCs' spreading behavior varies from shorter to longer linker‐based hydrogels, where on both surfaces hMSCs maintains their stemness as well as their adipogenic differentiation potential with a higher number of adipocytes for nanocomposites with a longer polymer linker. Overall, this work addresses the need for a new alternative for hMSCs culture allowing the cells to differentiate exclusively into adipocytes. This material represents a cell‐responsive platform with a tissue‐mimicking architecture given by the mechanical and morphological properties of the hydrogel

    Gene Transfer of Calcitonin Gene-Related Peptide Inhibits Macrophages and Inflammatory Mediators in Vein Graft Disease

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    Vein graft disease is a chronic inflammatory disease and limits the late results of coronary revascularization. Calcitonin gene-related peptide (CGRP) inhibits macrophages infiltrated and inflammatory mediators, we hypothesized that transfected CGRP gene inhibits macrophages infiltrated and inflammatory mediators in vein graft disease. Autologous rabbit jugular vein grafts were incubated ex vivo in a solution of mosaic adeno-associated virus vectors containing CGRP gene (AAV2/1.CGRP) 、escherichia coli lac Z gene (AAV2/1.LacZ) or saline and then interposed in the carotid artery. Intima/media ratio were evaluated at postoperative 4 weeks, Macrophages were marked with CD68 antibody by immunocytochemistry. Inflammatory mediators were mensurated with real-time PCR. Neointimal thickening was significantly suppressed in AAV2/1.CGRP group. Macrophages infiltrated and inflammatory mediators monocyte chemoattractant protein-1 (MCP-1)、tumor necrosis factorα(TNF-α)、inducible nitricoxide synthase (iNOS)、matrix metalloproteinase-9 (MMP-9) was significantly suppressed in AAV2/1.CGRP group.Gene transfected AAV2/1.CGRP suppressed neointimal hyperplasia in vein graft disease by suppressed macrophages infiltrated and inflammatory mediators

    Decision analysis of slope ecological restoration based on AHP

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    The serious deterioration of the ecological environment comes from a large number of geological disasters. These disasters were caused by a number of engineering activities. Ecological restoration is an important measure to reduce geological disasters and protect the ecological environment. On the basis of the introduction of cast-in-situ grids technology, external-soil spray seeding technology and vegetation bag technology, according to the ecological restoration experiment of the road slope attach to the Three Gorges Pumped-Storage Power Station in Hohhot, decision analysis of slope ecological restoration is done with AHP. It is shown that in arid and semi-arid area, selection of slope ecological restoration scheme mainly needs considering the ecological effect and stability. The major factor of ecological effects is survival rate of vegetation. The major factor of stability is the stability in a whole. Cast-in-situ grids technology will be the first choice for ecological restoration of road slope in arid and semi-arid area. This study provides reference for decision of the slope ecological restoration in arid and semi-arid region

    Study on Matching Ability Between Cement Particle Size and Permeability in the Process of Oil Reservoir Plugging

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    In order to satisfy the plugging demands of injecting the cement plugging agent into reservoirs with different radial depths, the technical studies of cement particle size optimization should be conducted. Through indoor experiment, the relationship between cement particle size and permeability was investigated by both macroscopic and microcosmic analysis. It is observed that the reservoirs which permeabilities are within 50~200mD are matching well with the cement agents which particle sizes are less than 5ÎŒm. And the permeabilities within 200~400mD are matching well with the cement agents which particle sizes are within 5~10ÎŒm, the permeabilities within 400~700mD are matching well with the cement agents which particle sizes are within 10~20ÎŒm, the permeabilities are above 700mD are matching well with the cement agents which particle sizes are more than 20ÎŒm. The plugging success rates of all the matching experiments are exceeding 90%. This research result is important to direct the plugging operation in the field.Key words: Plugging off and channeling prevention; Cement particle size; Permeability; Matching relationship; Experimental stud

    Postoperative Radiotherapy and N2 Non-small Cell Lung Cancer Prognosis: A Retrospective Study Based on Surveillance, Epidemiology, and End Results Database

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    The purpose of this study is to clarify the significance of postoperative radiotherapy for N2 lung cancer. This study aimed to investigate the effect of postoperative radiotherapy on the survival and prognosis of patients with N2 lung cancer. Data from 12,000 patients with N2 lung cancer were extracted from the Surveillance, Epidemiology, and End Results database (2004-2012). Age at disease onset and 5-year survival rates were calculated. Survival curves were plotted using the Kaplan-Meier method. The univariate log-rank test was performed. Multivariate Cox regression were used to examine factors affecting survival. Patients’ median age was 67 years (mean 66.46 ± 10.03). The 5-year survival rate was 12.55%. Univariate analysis revealed age, sex, pathology, and treatment regimen as factors affecting prognosis. In multivariate analysis, when compared to postoperative chemotherapy, postoperative chemoradiotherapy was better associated with survival benefits (hazard ratio [HR]= 0.85, 95% confidence interval [CI]: 0.813-0.898, P <0.001). Propensity score matching revealed that patients who had received postoperative chemoradiotherapy had a better prognosis than did patients who had received postoperative chemotherapy (HR=0.869, 95% CI: 0.817-0.925, P <0.001). Female patients and patients aged <65 years had a better prognosis than did their counterparts. Patients with adenocarcinoma had a better prognosis than did patients with squamous cell carcinoma. Moreover, prognosis worsened with increasing disease T stage. Patients who had received postoperative chemoradiotherapy had a better prognosis than did patients who had received postoperative chemotherapy. Postoperative radiotherapy was an independent prognostic factor in this patient group
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