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Authors: Hu, Kun | He, Fengyou

Article Type: Research Article

Abstract: Traditional synchronous motor system has complicated structure and is difficult to maintain. In view of the mentioned problem, this paper aims to propose a new structure brushless synchronous motor where AC exciter and synchronous motor using the same core. Two concentric single-phase winding grooves are cut on stator and rotor respectively, with the stator single-phase field winding laying in the stator single-phase winding groove, and the rotor AC induction winding laying in the rotor single-phase winding groove. The AC power from AC exciter is rectified by the rotating rectifier for the DC field winding. The results of the proposed structural …design and FEA of the new structure brushless wound field synchronous motor show that the new structure is simple in structure, low in loss, high in efficiency and promising in its future application. Show more

Keywords: Wound field synchronous motor, AC exciter, rotating rectifier, brushless excitation, finite element analysis

DOI: 10.3233/JAE-140071

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 46, no. 4, pp. 1009-1019, 2014

Authors: Fang, Lei | Tan, Guojun | Yin, Shi | Hu, Kun

Article Type: Research Article

Abstract: This paper focuses on the analysis of the starting capacity and temperature field of the line-start permanent magnet synchronous motor with the anti-salient pole. In order to further improve the performance of the traditional LSPMSM, the magnet structure is optimized to get better starting properties. Further, the models have been applied to investigate the impact of anti-salient pole on the efficiency and power factor. The temperature field of proposed motor with anti-salient pole has been compared to the traditional LSPMSM with classical rotor. Prototype machines with the two rotors have been built and tested. Experimental results are compared in terms …of starting, efficiency, power factor and temperature. It has been found that anti-salient pole improves the overall properties of the LSPMSM. Show more

Keywords: Line-start permanent magnet synchronous motor, anti-salient pole, starting characteristic, temperature field

DOI: 10.3233/JAE-150179

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 53, no. 4, pp. 605-616, 2017

Authors: Hu, Kun | Jiang, Hao | Wang, Shuang | Li, Fei

Article Type: Research Article

Abstract: This paper addresses the balancing of global and local searches in the recently proposed AO (Aquila Optimizer) algorithm. The original random algorithm is modified using normal-distribution parameters, and an adaptive function represented by a Weibull function is added to the motion law of the predator. Sixteen benchmark functions are used to test the improved algorithm against several recently developed algorithms. The results show that the accuracy and convergence speed of the modified algorithm are improved while the advantages of the original algorithm are retained. In solving the problems of a complex calculation and limited solution in the design of a …hybrid electromagnetic structure based on a Halbach array, a prediction model based on the improved algorithm and generalized regression neural network (GRNN) is designed for improved prediction accuracy of the GRNN. Thirty groups of data are obtained using Ansoft, and the prediction accuracy of the improved GRNN is verified using the data. The mean squared error (MSE) of normalized prediction results reaches 0.1404. The improved prediction model has the prediction error less than 10% and its performance is better than the RBF and the KCV-GRNN. Show more

DOI: 10.3233/JAE-210206

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 71, no. 1, pp. 21-44, 2023

Authors: Sun, Haoqi | Li, Peng | Gao, Lei | Yang, Jingyun | Yu, Lei | Buchman, Aron S. | Bennett, David A. | Westover, M. Brandon | Hu, Kun

Article Type: Research Article

Abstract: Background: Fractal motor activity regulation (FMAR), characterized by self-similar temporal patterns in motor activity across timescales, is robust in healthy young humans but degrades with aging and in Alzheimer’s disease (AD). Objective: To determine the timescales where alterations of FMAR can best predict the clinical onset of AD. Methods: FMAR was assessed from actigraphy at baseline in 1,077 participants who had annual follow-up clinical assessments for up to 15 years. Survival analysis combined with deep learning (DeepSurv) was used to examine how baseline FMAR at different timescales from 3 minutes up to 6 hours contributed differently to the risk for incident clinical …AD. Results: Clinical AD occurred in 270 participants during the follow-up. DeepSurv identified three potential regions of timescales in which FMAR alterations were significantly linked to the risk for clinical AD: <10, 20–40, and 100–200 minutes. Confirmed by the Cox and random survival forest models, the effect of FMAR alterations in the timescale of <10 minutes was the strongest, after adjusting for covariates. Conclusions: Subtle changes in motor activity fluctuations predicted the clinical onset of AD, with the strongest association observed in activity fluctuations at timescales <10 minutes. These findings suggest that short actigraphy recordings may be used to assess the risk of AD. Show more

Keywords: Actigraphy, Alzheimer’s disease, deep learning, motor activity

DOI: 10.3233/JAD-230928

Citation: Journal of Alzheimer's Disease, vol. 98, no. 1, pp. 209-220, 2024

Authors: Tao, Jing | Liu, Jiao | Liu, Weilin | Huang, Jia | Xue, Xiehua | Chen, Xiangli | Wu, Jinsong | Zheng, Guohua | Chen, Bai | Li, Ming | Sun, Sharon | Jorgenson, Kristen | Lang, Courtney | Hu, Kun | Chen, Shanjia | Chen, Lidian | Kong, Jian

Article Type: Research Article

Abstract: The aim of this study is to investigate and compare how 12-weeks of Tai Chi Chuan and Baduanjin exercise can modulate brain structure and memory function in older adults. Magnetic resonance imaging and memory function measurements (Wechsler Memory Scale-Chinese revised, WMS-CR) were applied at both the beginning and end of the study. Results showed that both Tai Chi Chuan and Baduanjin could significantly increase grey matter volume (GMV) in the insula, medial temporal lobe, and putamen after 12-weeks of exercise. No significant differences were observed in GMV between the Tai Chi Chuan and Baduanjin groups. We also found that compared …to healthy controls, Tai Chi Chuan and Baduanjin significantly improved visual reproduction subscores on the WMS-CR. Baduanjin also improved mental control, recognition, touch, and comprehension memory subscores of the WMS-CR compared to the control group. Memory quotient and visual reproduction subscores were both associated with GMV increases in the putamen and hippocampus. Our results demonstrate the potential of Tai Chi Chuan and Baduanjin exercise for the prevention of memory deficits in older adults. Show more

Keywords: Aging, Baduanjin, memory, mind-body exercise, Tai Chi Chuan, voxel-based morphometry

DOI: 10.3233/JAD-170477

Citation: Journal of Alzheimer's Disease, vol. 60, no. 2, pp. 389-400, 2017