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An Improved Spatially Selective Noise Filtration for Real-time Denoising of Acoustic Emission Signal
Jian Wang,Guangming Li,Peng Sun,Ruijuan Jiang,Yiyan Chen 보안공학연구지원센터 2015 International Journal of Signal Processing, Image Vol.8 No.7
The denoising of acoustic emission (AE) signal plays an important role in structural health monitoring. This paper proposes the improved spatially selective noise filtration (SSNF) which can eliminate the Gaussian white noise well. Firstly, through the comparison of different vanishing moments, “db5” is chose as the mother wavelet. And the Mallat algorithm is used in the composition and reconstruction of signal processing. Secondly, according to the signal noise ratio of wavelet reconstructed coefficients of AE signal, two coefficients are chosen to the next step. Lastly, the denoising algorithm uses the high degree of correlation between coefficients to realize the improved SSNF. Compared with the SSNF, the improved SSNF can avoid “glitches” and realize real-time denoising. And according to the simulation results, the improved SSNF can realize real-time denoising of AE signal.
Xin Wang,Guangming Zhuang,Jianwei Xia,Guoliang Chen,Huasheng Zhang 제어·로봇·시스템학회 2022 International Journal of Control, Automation, and Vol.20 No.12
This paper addresses the problem of observer-based extended dissipative control for singular Markovian jump systems with time-varying delays. By using relaxed Lyapunov-Krasovskii functional approach and strict linear matrix inequality method, sufficient conditions are proposed to ensure that the delayed singular Markovian jumping system is stochastically admissible and extended dissipative. Based on these conditions, a desired observer-based memory state feedback controller is designed to ensure that the closed-loop system satisfies stochastic admissibility and extended dissipativity. Finally, two examples including a numerical example and an oil catalytic cracking process are provided to illustrate the effectiveness of the proposed methods.
Kun Ma,Guangming Zhuang,Jianwei Xia,Guoliang Chen,Huasheng Zhang 제어·로봇·시스템학회 2021 International Journal of Control, Automation, and Vol.19 No.9
This paper considers the topic of the observer-based non-fragile mixed passivity and H∞ state feedback control for time-varying delay and norm-bounded parameter uncertainties fuzzy stochastic Markovian jump system subject to quantized measurements. The aim of this paper is to provide a suitable observer-based non-fragile state feedback controller to enhance stochastic stabilization of the closed-loop system and satisfy mixed passivity and H∞ performance. By constructing mode-dependent Lyapunov-Krasovskii functional, novel conditions are achieved in virtue of linear matrix inequalities. Two examples including truck-trailer model are given to illustrate the effectiveness of the developed method.
Wei Wang,Guangming Zhang,Yuguang Niu,Zhenyu Chen,Peiran Xie,Zhe Chen 제어·로봇·시스템학회 2022 International Journal of Control, Automation, and Vol.20 No.5
The operating flexibility of the power units is getting increasing attention from power systems especially those with large-scale fluctuating renewable energies. However, the combined heat and power (CHP) units are getting a bottleneck because their electricity productions are restricted by heat productions. This study aims to develop an electric-heat coordinated control strategy to make the CHP units more flexible. First of all, the dynamic model for a 300 MW CHP unit is set up, and its linear state-space description is obtained. A control strategy based on linear quadratic regulator (LQR) is then developed to satisfy different heat-power demands in various operating conditions. The control weights Q and R are optimized by particle swarm optimization. Moreover, the improved coordinated control strategy based on precise energy balance is put forward to increase the CHP power ramp rate considering electricity priority strategy and recovery control of the heat source. Finally, the simulation results show that the improved strategy is suitable for various CHP operating scenarios, and the case for electricity priority and heat recovery control significantly improves the unit power rate on the premise of stable heat supply. This work provides a reliable and flexible control mode for CHP units, which can support the power system stability and renewable energy integration.
Thermodynamic analysis of hybrid two-stage CO2 mechanical compression–ejector cooling cycle
Ierin Volodymyr,Chen Guangming,Hao Xinyue,Volovyk Oleksii 대한설비공학회 2023 International Journal of Air-Conditioning and Refr Vol.31 No.1
In the present study, the main results of thermodynamic analysis of the hybrid two-stage carbon dioxide (CO2) transcritical mechanical compression–ejector cooling cycle using R245ca are provided. In the proposed cycle, an increase in the energy efficiency of a mechanical compression refrigeration machine (MCRM) is provided by additional supercooling of CO2 after the gas cooler due to the use of cold obtained in an ejector cooling machine (ECM). The ECM uses part of the superheated vapor heat after the high-pressure compressor and the intermediate pressure heat after the low-pressure compressor. This solution provides intermediate cooling of CO2 vapor without using an external cooling medium. The proposed method of computation makes it possible to determine the optimal parameters of the hybrid cooling cycle for the design conditions, ensuring the maximum possible MCRM efficiency. At the same time, the method considers the need to determine the optimal gas cooler pressure – a parameter that has a significant impact on efficiency growth. The effect of the intermediate pressure is extremely insignificant and is defined as the geometric mean value of the product of the gas cooler and evaporator pressures. The results show an increase in efficiency of the two-stage CO2 MCRM by up to 31.6% at high temperatures of the environment. In addition, as a result of the exergy analysis, components have been identified, the improvement of which can lead to an additional increase in the efficiency of the entire system. As follows from the data obtained, the greatest attention should be paid to improving the ejector and reducing throttle losses in the CO2 cycle. In the present study, the main results of thermodynamic analysis of the hybrid two-stage carbon dioxide (CO 2 ) transcritical mechanical compression–ejector cooling cycle using R245ca are provided. In the proposed cycle, an increase in the energy efficiency of a mechanical compression refrigeration machine (MCRM) is provided by additional supercooling of CO 2 after the gas cooler due to the use of cold obtained in an ejector cooling machine (ECM). The ECM uses part of the superheated vapor heat after the high-pressure compressor and the intermediate pressure heat after the low-pressure compressor. This solution provides intermediate cooling of CO 2 vapor without using an external cooling medium. The proposed method of computation makes it possible to determine the optimal parameters of the hybrid cooling cycle for the design conditions, ensuring the maximum possible MCRM efficiency. At the same time, the method considers the need to determine the optimal gas cooler pressure – a parameter that has a significant impact on efficiency growth. The effect of the intermediate pressure is extremely insignificant and is defined as the geometric mean value of the product of the gas cooler and evaporator pressures. The results show an increase in efficiency of the two-stage CO 2 MCRM by up to 31.6% at high temperatures of the environment. In addition, as a result of the exergy analysis, components have been identified, the improvement of which can lead to an additional increase in the efficiency of the entire system. As follows from the data obtained, the greatest attention should be paid to improving the ejector and reducing throttle losses in the CO 2 cycle.
Rongxin Liao,Kehong Chen,Jinjin Li,Hengqiu He,Guangming Yi,Mingfeng Huang,Rongrong Chen,Lu Shen,Xiaoyue Zhang,Zaicheng Xu,Zhenzhou Yang,Yuan Peng 대한암학회 2023 Cancer Research and Treatment Vol.55 No.3
Purpose Oligometastatic non–small cell lung cancer (NSCLC) patients have been increasingly regarded as a distinct group that could benefit from local treatment to achieve a better clinical outcome. However, current definitions of oligometastasis are solely numerical, which are imprecise because of ignoring the biological heterogeneity caused by genomic characteristics. Our study aimed to profile the molecular alterations of oligometastatic NSCLC and elucidate its potential difference from polymetastasis. Materials and Methods We performed next-generation sequencing to analyze tumors and paired peripheral blood from 77 oligometastatic and 21 polymetastatic NSCLC patients to reveal their genomic characteristics and assess the genetic heterogeneity. Results We found ERBB2, ALK, MLL4, PIK3CB, and TOP2A were mutated at a significantly lower frequency in oligometastasis compared with polymetastasis. EGFR and KEAP1 alterations were mutually exclusive in oligometastatic group. More importantly, oligometastasis has a unique significant enrichment of apoptosis signaling pathway. In contrast to polymetastasis, a highly enriched COSMIC signature 4 and a special mutational process, COSMIC signature 14, were observed in the oligometastatic cohort. According to OncoKB database, 74.03% of oligometastatic NSCLC patients harbored at least one actionable alteration. The median tumor mutation burden of oligometastasis was 5.00 mutations/Mb, which was significantly associated with smoking, DNA damage repair genes, TP53 mutation, SMARCA4 mutation, LRP1B mutation, ABL1 mutation. Conclusion Our results shall help redefine oligometastasis beyond simple lesion enumeration that will ultimately improve the selection of patients with real oligometastatic state and optimize personalized cancer therapy for oligometastatic NSCLC.