921 research outputs found

    Fault Diagnosis for Power Electronics Converters based on Deep Feedforward Network and Wavelet Compression

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    A fault diagnosis method for power electronics converters based on deep feedforward network and wavelet compression is proposed in this paper. The transient historical data after wavelet compression are used to realize the training of fault diagnosis classifier. Firstly, the correlation analysis of the voltage or current data running in various fault states is performed to remove the redundant features and the sampling point. Secondly, the wavelet transform is used to remove the redundant data of the features, and then the training sample data is greatly compressed. The deep feedforward network is trained by the low frequency component of the features, while the training speed is greatly accelerated. The average accuracy of fault diagnosis classifier can reach over 97%. Finally, the fault diagnosis classifier is tested, and final diagnosis result is determined by multiple-groups transient data, by which the reliability of diagnosis results is improved. The experimental result proves that the classifier has strong generalization ability and can accurately locate the open-circuit faults in IGBTs.Comment: Electric Power Systems Researc

    Patient-centred care and patient autonomy: doctors' views in Chinese hospitals

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    Background: Patient-centred care and patient autonomy is one of the key factors to better quality of service provision, hence patient outcomes. It enables the development of patients’ trusts which is an important element to a better doctor-patient relationship. Given the increasing number of patient disputes and conflicts between patients and doctors in Chinese public hospital, it is timely to ensure patient-centred care is fully and successfully implemented. However, limited studies have examined the views and practice in different aspects of patient-centred care among doctors in the Chinese public hospitals. Methods: A quantitative approach was adopted by distributing paper-based questionnaires to doctors and patients in two hospitals (Level III and Level II) in Jinan, Shandong province, China. Results: In total, 614 doctors from the surgical and internal medicine units of the two hospitals participated in the survey yielding 90% response rates. The study confirmed the inconsistent views among doctors in terms of their perception and practice in various aspects patient-centred care and patient autonomy regardless of the hospital where they work (category II or category III), their unit speciality (surgical or non-surgical), their gender or seniority. The high proportion of doctors (more than 20%) who did not perceive the importance of patient consultation prior to determining diagnostic and treatment procedure is alarming. This in in part due to the belief held by more than half of the doctors that patients were unable to make rational decisions and their involvement in treatment planning process did not necessarily lead to better treatment outcomes. Conclusion: The study calls for the development of system level policy and organisation wide strategies in encouraging and enabling the practice of patient-centred care and patient autonomy with the purposes of improving the quality of the service provided to patients by Chinese hospitals

    Strict Stability Criteria for Impulsive Functional Differential Systems

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    Double suicide genes selectively kill human umbilical vein endothelial cells

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    <p>Abstract</p> <p>Background</p> <p>To construct a recombinant adenovirus containing CDglyTK double suicide genes and evaluate the killing effect of the double suicide genes driven by kinase domain insert containing receptor (KDR) promoter on human umbilical vein endothelial cells.</p> <p>Methods</p> <p>Human KDR promoter, <it>Escherichia coli </it>(<it>E. coli</it>) cytosine deaminase (CD) gene and the herpes simplex virus-thymidine kinase (TK) gene were cloned using polymerase chain reaction (PCR). Plasmid pKDR-CDglyTK was constructed with the KDR promoter and CDglyTK genes. A recombinant adenoviral plasmid AdKDR-CDglyTK was then constructed and transfected into 293 packaging cells to grow and harvest adenoviruses. KDR-expressing human umbilical vein endothelial cells (ECV304) and KDR-negative liver cancer cell line (HepG2) were infected with the recombinant adenoviruses at different multiplicity of infection (MOI). The infection rate was measured by green fluorescent protein (GFP) expression. The infected cells were cultured in culture media containing different concentrations of prodrugs ganciclovir (GCV) and/or 5-fluorocytosine (5-FC). The killing effects were measured using two different methods, i.e. annexin V-FITC staining and terminal transferase-mediated dUTP nick end-labeling (TUNEL) staining.</p> <p>Results</p> <p>Recombinant adenoviruses AdKDR-CDglyTK were successfully constructed and they infected ECV304 and HepG2 cells efficiently. The infection rate was dependent on MOI of recombinant adenoviruses. ECV304 cells infected with AdKDR-CDglyTK were highly sensitive to GCV and 5-FC. The cell survival rate was dependent on both the concentration of the prodrugs and the MOI of recombinant adenoviruses. In contrast, there were no killing effects in the HepG2 cells. The combination of two prodrugs was much more effective in killing ECV304 cells than GCV or 5-FC alone. The growth of transgenic ECV304 cells was suppressed in the presence of prodrugs.</p> <p>Conclusion</p> <p>AdKDR-CDglyTK/double prodrog system may be a useful method for suppressing tumor angiogenesis.</p

    Doctors in Chinese public hospitals: demonstration of their professional identities

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    Background: An increase in the number of medical disputes and violence against doctors indicates a lack of trust in the medical profession by society in Chinese public hospitals. Empirical evidence confirms that one cause is the lack of professional identity demonstrated by doctors. Medical professionals are required to maintain high standards of competence and moral responsibility, and demonstrate qualities such as respect, compassion, integrity, responsiveness to needs, and commitment to sound ethical practice in order to maintain professional privilege. These principles and appropriate professional conduct are the foundation of the professional identity of the medical profession. Methods: A quantitative approach was adopted by distributing paper-based questionnaires to doctors and patients in two hospitals (Level III and Level II) in Jinan, Shandong province, China. Findings: In total, 614 doctors and 1184 inpatients on discharge from the surgical and internal medicine units of the two hospitals participated in the survey yielding 90% response rates. The study confirmed the variation amongst doctors in demonstrating their professionalism in terms of respecting patients’ views and preferences when determining diagnostic procedures and treatment plans, and when making ethical decisions. Although 90% patients indicated that they showed respects to doctors, close to 20% of the doctors disagreed that they received high respect from patients. About 12% of doctors prescribed unnecessary diagnostic procedures to patient for the purpose of generating profit and more than 20% of patients indicated that they gave gifts to doctors in order to receive better treatment. Conclusions: Although about 80% of doctors demonstrated certain aspects of professionalism required by practitioners, the inconsistency across the medical workforce may exacerbate tense doctor-patient relationships. A review of medical curricula and focus of the internship program is required in order to assist medical graduates with forming required professional identity in order to improve patient satisfaction and better clinical outcomes. To be effective, a more systematic approach is recommended

    View Synthesis of Dynamic Scenes based on Deep 3D Mask Volume

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    Image view synthesis has seen great success in reconstructing photorealistic visuals, thanks to deep learning and various novel representations. The next key step in immersive virtual experiences is view synthesis of dynamic scenes. However, several challenges exist due to the lack of high-quality training datasets, and the additional time dimension for videos of dynamic scenes. To address this issue, we introduce a multi-view video dataset, captured with a custom 10-camera rig in 120FPS. The dataset contains 96 high-quality scenes showing various visual effects and human interactions in outdoor scenes. We develop a new algorithm, Deep 3D Mask Volume, which enables temporally-stable view extrapolation from binocular videos of dynamic scenes, captured by static cameras. Our algorithm addresses the temporal inconsistency of disocclusions by identifying the error-prone areas with a 3D mask volume, and replaces them with static background observed throughout the video. Our method enables manipulation in 3D space as opposed to simple 2D masks, We demonstrate better temporal stability than frame-by-frame static view synthesis methods, or those that use 2D masks. The resulting view synthesis videos show minimal flickering artifacts and allow for larger translational movements

    A symplectic dynamics approach to the spatial isosceles three-body problem

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    We study the spatial isosceles three-body problem from the perspective of Symplectic Dynamics. For certain choices of mass ratio, angular momentum, and energy, the dynamics on the energy surface is equivalent to a Reeb flow on the tight three-sphere. We find a Hopf link formed by the Euler orbit and a symmetric brake orbit, which spans an open book decomposition whose pages are annulus-like global surfaces of section. In the case of large mass ratios, the Hopf link is non-resonant, forcing the existence of infinitely many periodic orbits. The rotation number of the Euler orbit plays a fundamental role in the existence of periodic orbits and their symmetries. We explore such symmetries in the Hill region and show that the Euler orbit is negative hyperbolic for an open set of parameters while it can never be positive hyperbolic. Finally, we address convexity and determine for each parameter whether the energy surface is strictly convex, convex, or non-convex. Dynamical consequences of this fact are then discussed.Comment: 66 pages, 15 figure
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