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Abdalla Babiker,Changfeng Yan,Qiang Li,Jiadong Meng,Lixiao Wu 대한기계학회 2021 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.35 No.2
Rolling bearing failure is widely regarded as a failure form of industrial machines. Owing to the poor operating circumstance with the stochastic contact between rolling elements, the performance of the bearing will deteriorate over time and cause a cascade breakdown in the mechanical system. Early fault detection has been found to be an effective strategy to avoid economic loss. Therefore, an integration method for fault diagnosis that combines backtracking strategy, improved variational mode decomposition (VMD), and infogram is proposed to tackle the challenge of the early feature extraction from the heavy noisy non-stationary signal. The backtracking strategy is adopted to track the data sample points earlier than the fault threshold determined based on the kurtosis index. The optimum parameters α and K of VMD are acquired through the particle swarm optimization (PSO) algorithm. In this way, the more accurate intrinsic mode functions (IMFs) can be gained by the improved VMD. The optimum IMFs are acquired according to the maximum values of kurtosis and correlation coefficients, and these IMFs can be reconstructed into the noise reduction signal. Since envelope analysis requires the selection of the appropriate central frequency and bandwidth, infogram is utilized to select the values of them. A simulated case is applied to demonstrate the validation of the proposed method. And to further illustrate its practicality, it is employed to perform early fault diagnosis for an experimental case. According to the diagnosis results, the proposed method has conspicuous superiority over the other existing technologies for estimating incipient fault time of the bearing.
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Chen Hao,Wang Chunwei,Wang You,Chen Yilin,Wan Meng,Zhu Jiadong,Zhu Aixia 아세아·태평양축산학회 2021 Animal Bioscience Vol.34 No.4
Objective: This study aimed to determine the effects of soft pellet creep feed (SPCF) on growth performance and intestinal development in piglets. Methods: A total of 18 sows and their litters of crossbred piglets (14±2 days, 3.73±0.72 kg) were assigned to one of three dietary groups receiving i) powder creep feed (PCF), ii) hard pellet creep feed (HPCF) or iii) SPCF during the pre-weaning period. After weaning, piglets were selected for continuous evaluation of the three diets on growth performance and intestinal health. Results: In the pre-weaning period, the average daily feed intake and average daily dry matter intake were significantly higher in the SPCF group than the HPCF group (p<0.05). In the post-weaning and entire experimental period, the different diets had no significant effect on growth performance. At 10 d after weaning, the serum glucose concentration was lower in the SPCF group (p<0.05) than the other groups; a higher (p<0.05) villus height and lower (p<0.05) crypt depth in the jejunum were also observed in the SPCF group than the other groups; Meanwhile, in the duodenum and jejunum, the SPCF group had a higher (p<0.05) villus height to crypt depth ratio than the other groups; Furthermore, the higher (p<0.05) threshold cycle values of lactic acid bacteria and lower (p<0.05) threshold cycle values of Clostridium, Enterobacter and Escherichia coli were also observed in the SPCF group, and the sucrase and maltase activity was higher (p<0.05) in the SPCF group than the other groups in duodenum and ileum. Conclusion: The SPCF improved pre-weaning feed intake and decreased the negative effects of weaning stress in the intestine in piglets. Objective: This study aimed to determine the effects of soft pellet creep feed (SPCF) on growth performance and intestinal development in piglets.Methods: A total of 18 sows and their litters of crossbred piglets (14±2 days, 3.73±0.72 kg) were assigned to one of three dietary groups receiving i) powder creep feed (PCF), ii) hard pellet creep feed (HPCF) or iii) SPCF during the pre-weaning period. After weaning, piglets were selected for continuous evaluation of the three diets on growth performance and intestinal health.Results: In the pre-weaning period, the average daily feed intake and average daily dry matter intake were significantly higher in the SPCF group than the HPCF group (p<0.05). In the post-weaning and entire experimental period, the different diets had no significant effect on growth performance. At 10 d after weaning, the serum glucose concentration was lower in the SPCF group (p<0.05) than the other groups; a higher (p<0.05) villus height and lower (p<0.05) crypt depth in the jejunum were also observed in the SPCF group than the other groups; Meanwhile, in the duodenum and jejunum, the SPCF group had a higher (p<0.05) villus height to crypt depth ratio than the other groups; Furthermore, the higher (p<0.05) threshold cycle values of lactic acid bacteria and lower (p<0.05) threshold cycle values of <i>Clostridium, Enterobacter and Escherichia coli</i> were also observed in the SPCF group, and the sucrase and maltase activity was higher (p<0.05) in the SPCF group than the other groups in duodenum and ileum.Conclusion: The SPCF improved pre-weaning feed intake and decreased the negative effects of weaning stress in the intestine in piglets.
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Event Based On-line Tuning of Generalized Predictive Controllers Using an Improved Fuzzy Logic
Ning He,Gongbo Xu,Ruoxia Li,Shang Li,Jiadong Wang,Meng Zhang 제어·로봇·시스템학회 2022 International Journal of Control, Automation, and Vol.20 No.8
This article develops a novel approach for generalized predictive controller (GPC) tuning of multipleinput-multiple-output (MIMO) systems using an improved fuzzy logic and the event-triggered mechanism (ETM). First, the slope of the system output is considered as a new fuzzy target parameter to construct the fuzzy logic algorithm, based on which an improved fuzzy logic based GPC online tuning method is proposed. Second, in order to save the computation and communication resources for the online tuning of GPC parameters, ETM is further introduced to avoid unnecessary updates. Third, given the modified fuzzy algorithm and the aperiodic sampling framework caused by the ETM, the stability property of the closed-loop system under the proposed method is proved theoretically. Finally, the advantages of the developed technique are illustrated via a machine-furnace coordination system.
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