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Seismic Dynamic Response Analysis of Mountain Tunnels with Seismic Reduction and Isolation Measures
Zhongxian Liu,Tian-Chun Ai,Lei Huang,Si-Bo Meng,Ping-Lin Jiang 대한토목학회 2023 KSCE Journal of Civil Engineering Vol.27 No.1
In this paper, the multi-domain indirect boundary element method (IBEM) is developed for the seismic response analysis of double-line mountain tunnels with seismic reduction and isolation measures. The dynamic response of the tunnel with seismic reduction and isolation measures under incident SV waves is analyzed, and the effect of the mountain topography on the tunnel is also investigated. Further, the effects of the isolation layer and the grouting reinforcement with different thicknesses on the seismic response of the tunnel are discussed in detail. The results show that the scattering of seismic waves by mountain topography significantly increases tunnel stress. In general, with the increase of incident frequency, the isolation layer will increase the peak displacement of the tunnel by about 12.7% at most, and the isolation ratio of the isolation layer on the tunnel stress exceeds 40%. The seismic reduction performance of the grouting reinforcement also depends on the incident frequency, and the amplitude decreases by approximately 20% at most frequencies. However, it is possible that the lining displacement under high-frequency waves becomes larger. This method can provide valuable insights and assessments for damage prediction.
Genetically optimized self-tuning Fuzzy-PI controller for HVDC system
왕중선(Zhongxian Wang),양정제(Juengje Yang),안태천(Taechon Ahn) 대한전기학회 2006 정보 및 제어 심포지엄 논문집 Vol.2006 No.1
In this paper, we study an approach to design a self-tuning Fuzzy-PI controller in HVDC(High Voltage Direct Current) system. In the rectifier of conversional HVDC system, turning on, turning off, triggering and protections of thyristors have lots of problems that can make the dynamic instability and cannot damp the dynamic disturbance efficiently. The above problems are solved by adapting Fuzzy-PI controller for the fire angle control of rectifier.[7] The performance of the Fuzzy-PI controller is sensitive to the variety of scaling factors. The design procedure dwells on the use of evolutionary computing(Genetic Algorithms, GAs). Then we can obtain the optimal scaling factors of the Fuzzy-PI controller by Genetic Algorithms. In order to improve Fuzzy-PI controller, we adopt FIS to tune the scaling factors of the Fuzzy-PI controller on line. A comparative study has been performed between Fuzzy-PI and self-tuning Fuzzy-PI controller. to prove the superiority of the proposed scheme.
Adaptive Granule Control with the Aid of Rough Set Theory for a HVDC system
왕중선(Zhongxian Wang),양정제(Jeungje Yang),안태천(Taechon Ahn) 대한전기학회 2006 대한전기학회 학술대회 논문집 Vol.2006 No.11
A proportional intergral (PI) control strategy is commonly used for constant current and extinction angle control in a HVDC (High Voltage Direct Current) system. A PI control strategy is based on a stactic design where the gains of a PI controller are fixed. Since the response of a HVDC plant dynamically changes with variations in the operation point, a PI controller performance is far from optimum. The contribution of this paper is the presentation of the design of a rough set based, fuzzy adaptive control scheme. Experimental results that compare the performance of the adaptive control and PI control schemes are also given.
A Modified Reversible Data Hiding in Encrypted Images Using Random Diffusion and Accurate Prediction
Ming Li,Zhongxian Peng,Hai Nan 한국전자통신연구원 2014 ETRI Journal Vol.36 No.2
A modified version of Zhang’s reversible data hiding methodin encrypted images is proposed in this letter. To make full useof spatial correlation in natural images, the former idea ofblock division is thoroughly abandoned, whereas the randomdiffusion strategy is used. Additionally, the fluctuationmeasurement of pixels containing embedded data is improvedby accurate prediction. The experiment results reveal that ourproposed method is superior to both Zhang’s method and thelater improved version proposed by Hong and others.
Vibration analysis of FG porous rectangular plates reinforced by graphene platelets
Changlin Zhou,Zhongxian Zhan,Ji Zhang,Yuan Fang,Vahid Tahouneh 국제구조공학회 2020 Steel and Composite Structures, An International J Vol.34 No.2
The aim of this study is to investigate free vibration of functionally graded porous nanocomposite rectangular plates where the internal pores and graphene platelets (GPLs) are distributed in the matrix either uniformly or non-uniformly according to three different patterns. The elastic properties of the nanocomposite are obtained by employing Halpin-Tsai micromechanics model. The GPL-reinforced plate is modeled using a semi-analytic approach composed of generalized differential quadrature method (GDQM) and series solution adopted to solve the equations of motion. The proposed rectangular plates have two opposite edges simply supported, while all possible combinations of free, simply supported and clamped boundary conditions are applied to the other two edges. The 2-D differential quadrature method as an efficient and accurate numerical tool is used to discretize the governing equations and to implement the boundary conditions. The convergence of the method is demonstrated and to validate the results, comparisons are made between the present results and those reported by well-known references for special cases treated before, have confirmed accuracy and efficiency of the present approach. New results reveal the importance of porosity coefficient, porosity distribution, graphene platelets (GPLs) distribution, geometrical and boundary conditions on vibration behavior of porous nanocomposite plates. It is observed that the maximum vibration frequency obtained in the case of symmetric porosity and GPL distribution, while the minimum vibration frequency is obtained using uniform porosity distribution.
Yu, Xiaoping,Lu, Zhongxian,Wu, Guorui,Tao, Linyong,Chen, Jianming,Zheng, Xusong,Xu, Hongxing Korean Society of Applied Entomology 2001 Journal of Asia-Pacific Entomology Vol.4 No.2
The virulence change (biotype), wing form development and immigration of brown planthopper (BPH) Nilaparvata lugens Stal, population in Zhejiang province was studied as compared to these BPH populations collected from Guangxi and Yunnan province, China and Philippines. The results indicate that the Zhejiang population could successfully infest variety IR26 and Mudgo after 1989, and ASD7 and IR36 after 1998, showing the characters of BPH biotype 2 and biotypes 3. The BPH tropical populations such as Guangxi population, however, adapted the resistant varieties IR26, Mudgo and ASD7 earlier. In 1997, the nymphal survival indices of Guangxi and Yunnan populations on Rathu Heenati (Bph3) were up to 70.9 and 66.7 respectively, higher than Zhejiang population. The Zhejiang populations show low brachupterous rates and have a negative correlation with nymphal density, belonging to the temperate type. The Philippine populations are almost brachypterous, however, the brachypterous rates of BPH males raise with the increase of nymphal density. The Guangxi population has a high brachypterous rate, being similar to the tropical type. On the other hand, tests showed that the lowest survival rate, longer duration of nymphs and the lightest weight of brachypterous female occurred in the $2^{nd}$ generation of BPH after continuously feeding on resistant variety. Physiologically, the highest activities of superoxide dismutase (SOD) and catalase (CAT) were detected in the second generation of the BPH feeding on resistant rice variety.
Jian Sun,Zhe Zhang,Zhongxian Xia,Xin Fang,Renyun Guan,Guangxiang Zhang,Jinmei Yao 한양대학교 청정에너지연구소 2023 Journal of Ceramic Processing Research Vol.24 No.3
In order to investigate the influence of polyether ether ketone (PEEK) and its composite cage on the dry friction characteristicsof silicon nitride all-ceramic ball bearings, this paper firstly conducted a theoretical analysis of silicon nitride deep groove ballbearings subjected to radial load under dry friction conditions, and then conducted dry friction tests and simulation studieson PEEK, CF30 and PVX cage silicon nitride full ceramic ball bearings. The test results show that the temperature rise ofCF30 and PVX cage bearings is higher than that of PEEK cage bearings; the relationship between the root mean square valueof vibration of PEEK, CF30 and PVX cage bearings is PEEK cage bearings > CF30 cage bearings > PVX cage bearings; thesimulation model has good accuracy; Surface morphology analysis of the PVX cage bearing after the test show that thetransfer film has the effect of wear reduction and lubrication on the bearing. The results of the study have positive significancefor the research of transfer film lubricated bearings and the selection of cage materials.
Ning He,Qingqing Chen,Zhongxian Xu,Botao Bai,Chao Shen 제어·로봇·시스템학회 2024 International Journal of Control, Automation, and Vol.22 No.1
A new event-triggered model predictive control (ET-MPC) algorithm is proposed for continuous perturbed nonlinear systems with constraints for the purpose of reducing computing burden and communication transmission. In the first step, an original event triggering condition is constructed based on the slope variation of the state error between the optimal prediction and the real state, i.e., the quasi quadratic differential (QQD) type eventtriggered mechanism. Secondly, the dual-mode control has been adopted to deal with the constrained nonlinear systems subject to disturbances, based on which the execution process of the proposed QQD based ET-MPC is described. In addition, the feasibility of the algorithm and closed-loop stability of the system have been strictly proved in theory. Lastly, two simulation examples are utilized to verify the effectiveness and applicability of the proposed algorithm.