3,206 research outputs found

    Sensorless stator field orientation controlled induction motor drive with a fuzzy speed controller

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    AbstractA sensorless stator-field oriented control induction motor drive with a fuzzy logic speed controller is presented. First, a current-and-voltage parallel-model stator-flux estimator is established using measured phase currents and voltages of the induction motor. Then the estimated rotor shaft position is obtained from the magnitude and position of the estimated stator flux. The speed controller is developed by utilizing fuzzy logic control techniques. The control algorithms are realized by a DSP 6713 and, using a DSP F2812 to generate PWM signals to the power stage, drive the motor to experimentally validate the proposed approach

    Education for All in China : The Case of Migrant Children in County X

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    The purpose of this study is to examine the extent to which migrant girls and boys in China are integrated into the education system in urban areas in the context of implementing Education for All (EFA) policies. It explores the educational experiences of migrant children in urban areas, the government and school reactions to the issue of the education of migrant children, as well as the family-related factors that may affect their education. It aims at identifying the underlying factors that contribute to the disadvantages of migrant children in education. Social exclusion theory is applied in this study to help understand how and why migrant children are marginalized. The study also uses a gender approach to investigate possible gender differences in migrant children’s education based particularly on the Chinese cultural tradition. The study uses qualitative methods in a case study of County X in China, including document analysis, semi-structured interviews and observation. The research findings indicate that the urban education system remains partly exclusive and that migrant children meet several difficulties in integrating into urban society. The household registration system is regarded as one of the major factors that contribute to the marginalization of migrant children in the city. Migrant girls experience the dual disadvantage of being both migrant and female. The study specifically contributes knowledge about the group of ‘migrant and left-behind’ children. It argues that they experience problems both of adaptation and integration into the urban society and additional disadvantages from being left behind

    Best simultaneous approximation to totally bounded sequences in Banach spaces

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    This paper is concerned with the problem of best weighted simultaneous approximations to totally bounded sequences in Banach spaces. Characterization results from convex sets in Banach spaces are established under the assumption that the Banach space is uniformly smooth.National Natural Science Foundation of ChinaProgram for New Century Excellent Talent in UniversityDirección General de Investigación Científica y TécnicaJunta de Andalucí

    The controlling nutritional status score and clinical outcomes in patients with heart failure: Pool analysis of observational studies.

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    Background and aims Malnutrition is very common in patients with heart failure (HF) and is associated with a worse clinical outcome. The Controlling Nutritional Status (CONUT) score is an easily derived index for the evaluation of malnutrition. This study aimed to evaluate the association between the CONUT score and the prognosis in patients with HF. Methods and results Electronic databases were searched for potential studies from inception up to February 15, 2022. Observational cohort studies included adult participants with HF, and reported the associations between the CONUT score and the adjusted relative risk (RR) of all-cause mortality, and patients with composite major adverse cardiac outcomes (MACEs) were included. We finally included 18 studies comprising 12,532 participants with HF for analysis. The median age of the patients was 70.5 years old, and 35.4% were women. After a median follow-up duration of 32.5 months, patients with HF with a higher CONUT score were associated with a higher risk of all-cause mortality (per 1 increment of the CONUT score: RR, 1.21, 95% CI, 1.13-1.29, I 2 = 68%, P for heterogeneity = 0.002) and MACEs (per 1 increment of the CONUT score: RR, 1.14, 95% CI, 1.06-1.23, I 2 = 81%, P for heterogeneity <0.0001) after adjusting for other prognostic factors. When the CONUT score was divided into the normal nutritional status and malnourished status, malnourished patients with HF were associated with increased risks of all-cause death (RR, 1.61, 95% CI, 1.40-1.85, I 2 = 17%, P for heterogeneity = 0.29) and MACEs (RR, 2.12, 95% CI, 1.49-3.02, I 2 = 87%, P for heterogeneity <0.0001), compared with those with normal nutritional status. Conclusions The CONUT score is associated with the clinical outcomes in patients with HF, and can be used as a screening tool of nutritional status in HF to improve prognosis

    Entangling two giant atoms via a topological waveguide

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    We study the entanglement generation of two two-level giant atoms coupled to a photonic waveguide, which is formed by a Su-Schrieffer-Heeger (SSH) type coupled-cavity array. Here, each atom is coupled to the waveguide through two coupling points. We focus on the two-atom separate-coupling case, and consider sixteen coupling configurations for the coupling-point distributions between the two atoms and the waveguide. We derive quantum master equations to govern the evolution of the two atoms and characterize atomic entanglement by calculating the concurrence of the two-atom states. It is found that the two giant-atom entanglement depends on the coupling configurations and the coupling-point distance of the giant atoms. In particular, the entanglement dynamics of the two giant atoms in fourteen coupling configurations depends on the dimerization parameter of the SSH waveguide. According to the self-energies of the two giant atoms, we find that ten of these sixteen coupling configurations can be divided into five pairs. We also show that delayed sudden birth of entanglement between the two giant atoms is largely enhanced in these five pairs of coupling configurations. This work will promote the study of quantum effects and coherent manipulation in giant-atom topological-waveguide-QED systems.Comment: 21 pages, 5 figures, submitted to New J. Phys. on Sep. 1st, 202
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