Time-varying Group Formation With Leader-following Control for Heterogeneous Multi-agent Systems

Xiangyang Du,Weixun Li,Jingyu Xiao,Zengqiang Chen 제어·로봇·시스템학회 2023 International Journal of Control, Automation, and Vol.21 No.7

This paper studies time-varying group formation control for heterogeneous multi-agent systems (MAS). Two subgroups of heterogeneous MAS consisting of second-order dynamic and Euler-Lagrange (E-L) dynamic agents, three subgroups of heterogeneous MAS consisting of first-order, second-order dynamic and E-L dynamic agents are considered respectively. Firstly, through the assumption of the formation-tracking feasibility condition and the design of the formation compensation vectors in the controller, the time-varying formation control can be transformed into a consensus problem. Then, a distributed controller based on neighbor information is designed and sufficient conditions for time-varying formation control are obtained. The time-varying group formation problem of heterogeneous MAS is analyzed by Lyapunov stability theory and eigenvalue theory. Finally, two simulation results show that the proposed controller can realize the time-varying formation control of heterogeneous group MAS.

Rolling bearing fault convolutional neural network diagnosis method based on casing signal

Xiangyang Zhang,Guo Chen,Tengfei Hao,Zhiyuan He 대한기계학회 2020 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.34 No.6

Affected by the transmission path, it is very difficult to diagnose the vibration signal of the rolling bearing on the aircraft engine casing. A fault diagnosis method based on convolutional neural network is proposed for the weak vibration signal of the casing under the excitation of rolling bearing fault. Firstly, the processing method of vibration signal is studied. Through comparison and analysis, it is found that the fault characteristics of rolling bearing are more easily expressed by continuous wavelet scale spectrum, and a better recognition rate is obtained. Finally, the experiment was carried out with an aero-engine rotor tester with a casing, and the method based on wavelet scale spectrum and convolutional neural network was used for diagnosis. The results were compared with the support vector machine method. The results show that the method has a high recognition rate for the weak fault signals of different fault types collected on the aero engine case, and its fault recognition rate reaches 95.82 %, which verifies the superiority and potential of the method for rolling bearing fault diagnosis.

The SIMP-SRV Method for Stiffness Topology Optimization of Continuum Structures

Zhou, Xiangyang,Chen, Liping,Huang, Zhengdong Society for Computational Design and Engineering 2007 International Journal of CAD/CAM Vol.7 No.1

In density-based topology optimization, 0/1 solutions are sought. Discrete topological problems are often relaxed with continuous design variables so that they can be solved using continuous mathematical programming. Although the relaxed methods are practical, grey areas appear in the optimum topologies. SIMP (Solid Isotropic Microstructures with Penalization) employs penalty schemes to suppress the intermediate densities. SRV (the Sum of the Reciprocal Variables) drives the solution to a 0/1 layout with the SRV constraint. However, both methods cannot effectively remove all the grey areas. SRV has some numerical aspects. In this work, a new scheme SIMP-SRV is proposed by combining SIMP and SRV approaches, where SIMP is employed to generate an intermediate solution to initialize the design variables and SRV is then adopted to produce the final design. The new method turned out to be very effective in conjunction with the method of moving asymptotes (MMA) when using for the stiffness topology optimization of continuum structures for minimum compliance. The numerical examples show that the hybrid technique can effectively remove all grey areas and generate stiffer optimal designs characterized with a sharper boundary in contrast to SIMP and SRV.

The Chitin-Induced Chimeric LYK4-ER Gene Improves the Heat Tolerance of Arabidopsis at the Seedling Stage

Linxiao Chen,Wei Xia,Jinxing Song,Mengqi Wu,Zhizhen Xu,Xiangyang Hu,Wenqing Zhang 한국식물학회 2020 Journal of Plant Biology Vol.63 No.4

Due to global warming, high temperature has become the main abiotic stress affecting plant growth worldwide. LysM-containing receptor-like kinase 4 (LYK4) is the receptor for chitin, and ERECTA(ER) is a key factor in plant tolerance to high temperature. In this study, we constructed a chitin-induced chimeric LYK4-ER gene, in which the extracellular region and transmembrane domain of the LYK4 gene are fused with the intracellular region of the ER gene. Colony PCR, RT-PCR and western blot analyses of LYK4-ER transcription in plants, confirmed that the LYK4-ER gene was successfully constructed and transferred into Arabidopsis. The LYK4-ER gene localized to the cytomembrane and cytoplasm in vivo because of the binding properties of the transmembrane domain of the LYK4-ER gene to the cell membrane. The transgenic plants showed a higher germination rate and germination index as well as a shorter mean germination time than the wild-type plants, indicating that the LYK4-ER gene increases the heat tolerance of Arabidopsis. The lower H2O2 content and relative electrolytic leakage of the transgenic plants showed that the status of these plants under heat stress was improved. UPLC-MS/MS was used to analyze the phytohormones content, which suggested that the transgenic plants exhibited improved heat tolerance through jasmonic acid signal transduction pathways.

Effect of strain amplitude and temperature on creep-fatigue behaviors of 9-12 % Cr steel

Jianfeng Mao,Jian Zhu,Xiangyang Li,Dasheng Wang,Fengping Zhong,Jichang Chen 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.5

The creep-fatigue behaviors of P92 steel under strain range of 0.3 %-0.5 % and test temperature of 600-650 °C was studied carefully in this paper. With the increase of temperature, the creep-fatigue life is significantly reduced, and more vulnerable to temperature than strain amplitude. In addition, the dislocation density decreases with increasing creep fatigue, and the martensite laths become coarser. Furthermore, the increase of strain amplitude leads to more significant secondary cracks and fatigue striation. The higher temperature causes much deeper and larger dimples. During the test, the growth and accumulation of precipitates inevitably lead to stress concentration, resulting in material fracture and destruction. Finally, the linear cumulative damage (LCD), the modified ductility exhaustion (MDE) and the frequency separation life (FSL) model are used to predict the creep-fatigue life of P92 steel, and it is found that the frequency separation life model had the highest prediction accuracy among the threes.

Application of Three-phase Hollow Fiber LPME using an Ionic Liquid as Supported Phase for Preconcentration of Malachite Green from Water Samples with HPLC Detection

Zou, Yanmin,Zhang, Zhen,Shao, Xiaoling,Chen, Yao,Wu, Xiangyang,Yang, Liuqing,Zhu, Jingjing,Zhang, Dongmei Korean Chemical Society 2014 Bulletin of the Korean Chemical Society Vol.35 No.2

A novel three-phase hollow fiber liquid phase microextraction was developed for the determination of malachite green (MG) in environmental waters, which selected [BMIM][$PF_6$] mixed with 1% trioctylphosphine oxide (TOPO) as supported phase. Several parameters (accepter phase pH, sample pH, supported phase membrane, volume of accepter phase, salinity, extraction time) that could affect extraction performance were investigated. Under the optimal extraction conditions, the established approach showed excellent characters as: high enrichment factor (212), wide linear range ($0.20-100{\mu}gL^{-1}$), low detection limit ($0.01{\mu}gL^{-1}$), good reproducibility (RSD, 8.9%, n=5) and satisfactory recovery (84.0-106.2%). The method was applied to detect MG at Yangtze River and pond waters in Zhenjiang, Jiangsu province, and 4 sites among 15 sampling sites were found MG with the concentration of $1.73-11.06{\mu}gL^{-1}$, which confirmed that the proposed environmentally friendly method was simple and effective for monitoring MG in aquatic system.

Experimental study on migration and transformation of selenium species and DFT calculation in WFGD simulated slurry

Shuangchen Ma,Fang Xu,Dao Qiu,Xiangyang Chen,Ruimin Wang 한국공업화학회 2022 Journal of Industrial and Engineering Chemistry Vol.109 No.-

Selenium is a harmful trace element emitted during the combustion process of coal-fired power plants. Most of the selenium is enriched in the downstream wet flue gas desulfurization system (WFGD). Thisstudy found that S2O28 is the most important factor affecting the oxidation of selenite. In the processof simulating slurry oxidation of selenite to selenate, the presence of S2O28 can increase the oxidationrate of selenate from about 50% to about 80%. At the same time, this study also considered the influenceof selenium concentration, initial pH, SO2 concentration and temperature etc. on the transformation ofselenium species. It was believed that the application of ORP to the indication of selenite oxidation statusneeds further demonstration. Energy Dispersive X-Ray Spectroscopy (EDX) and X-ray photoelectron spectroscopy(XPS) were used to confirm the migration of selenium in the desulfurization slurry to gypsum. Inaddition, DFT calculation was performed to obtain theoretical parameters for the adsorption of seleniteand selenate by gypsum. The results of this study are helpful to understand the transformation andmigration of selenium in the desulfurization system, which provide theoretical support for the realizationof selenium in-situ control.

Dynamic analysis of metro vehicle traveling on a high-pier viaduct under crosswind in Chongqing

Yunfei Zhang,Jun Li,Zhaowei Chen,Xiangyang Xu 한국풍공학회 2019 Wind and Structures, An International Journal (WAS Vol.29 No.5

Due to the rugged terrain, metro lines in mountain city across numerous wide rivers and deep valleys, resulting in instability of high-pier bridge and insecurity of metro train under crosswind. Compared with the conditions of no-wind, crosswind triggers severer vibration of the dynamic system; compared with the short-pier viaduct, the high-pier viaduct has worse stability under crosswind. For these reasons, the running safety of the metro vehicle traveling on a high-pier viaduct under crosswind is analyzed to ensure the safe operation in metro lines in mountain cities. In this paper, a dynamic model of the metro vehicle-track-bridge system under crosswind is established, in which crosswind loads model considering the condition of wind zone are built. After that, the evaluation indices and the calculation parameters have been selected, moreover, the basic characteristics of the dynamic system with high-pier under crosswind are analyzed. On this basis, the response varies with vehicle speed and wind speed are calculated, then the corresponding safety zone is determined. The results indicate that, crosswind triggers drastic vibration to the metro vehicle and high-pier viaduct, which in turn causes running instability of the vehicle. The corresponding safety zone for metro vehicle traveling on the high-pier is proposed, and the metro traffic on the high-pier bridge under crosswind should not exceed the corresponding limited vehicle speed to ensure the running safety.

Application of Three-phase Hollow Fiber LPME using an Ionic Liquid as Supported Phase for Preconcentration of Malachite Green from Water Samples with HPLC Detection

Yanmin Zou,Zhen Zhang,Xiaoling Shao,Yao Chen,Xiangyang Wu,Liuqing Yang,Jingjing Zhu,Dongmei Zhang 대한화학회 2014 Bulletin of the Korean Chemical Society Vol.35 No.2

A novel three-phase hollow fiber liquid phase microextraction was developed for the determination of malachite green (MG) in environmental waters, which selected [BMIM][PF6] mixed with 1% trioctylphosphine oxide (TOPO) as supported phase. Several parameters (accepter phase pH, sample pH, supported phase membrane, volume of accepter phase, salinity, extraction time) that could affect extraction performance were investigated. Under the optimal extraction conditions, the established approach showed excellent characters as: high enrichment factor (212), wide linear range (0.20-100 μg L-1), low detection limit (0.01 μg L-1), good reproducibility (RSD, 8.9%, n=5) and satisfactory recovery (84.0-106.2%). The method was applied to detect MG at Yangtze River and pond waters in Zhenjiang, Jiangsu province, and 4 sites among 15 sampling sites were found MG with the concentration of 1.73-11.06 μg L-1, which confirmed that the proposed environmentally friendly method was simple and effective for monitoring MG in aquatic system.

Optimal Gabor Filters for Steganalysis of Content-Adaptive JPEG Steganography

( Xiaofeng Song ),( Fenlin Liu ),( Liju Chen ),( Chunfang Yang ),( Xiangyang Luo ) 한국인터넷정보학회 2017 KSII Transactions on Internet and Information Syst Vol.11 No.1

The existing steganalysis method based on 2D Gabor filters can achieve a competitive detection performance for content-adaptive JPEG steganography. However, the feature dimensionality is still high and the time-consuming of feature extraction is relatively large because the optimal selection is not performed for 2D Gabor filters. To solve this problem, a new steganalysis method is proposed for content-adaptive JPEG steganography by selecting the optimal 2D Gabor filters. For the proposed method, the 2D Gabor filters with different parameter settings are generated first. Then, the feature is extracted by each 2D Gabor filter and the corresponding detection accuracy is used as the measure for filter selection. Next, some 2D Gabor filters are selected by a greedy strategy and the steganalysis feature is extracted by the selected filters. Last, the ensemble classifier is used to assemble the proposed steganalysis feature as well as the final steganalyzer. The experimental results show that the steganalysis feature extracted by the selected optimal 2D Gabor filters also can achieve a competitive detection performance while the feature dimensionality is reduced greatly.