Analysis of delay compensation in real-time dynamic hybrid testing with large integration time-step

Fei Zhu,Jin-Ting Wang,Feng Jin,Yao Gui,Meng-Xia Zhou 국제구조공학회 2014 Smart Structures and Systems, An International Jou Vol.14 No.6

With the sub-stepping technique, the numerical analysis in real-time dynamic hybrid testing is split into the response analysis and signal generation tasks. Two target computers that operate in real-time may be assigned to implement these two tasks, respectively, for fully extending the simulation scale of the numerical substructure. In this case, the integration time-step of solving the dynamic response of the numerical substructure can be dozens of times bigger than the sampling time-step of the controller. The time delay between the real and desired feedback forces becomes more striking, which challenges the well-developed delay compensation methods in real-time dynamic hybrid testing. This paper focuses on displacement prediction and force correction for delay compensation in the real-time dynamic hybrid testing with a large integration time-step. A new displacement prediction scheme is proposed based on recently-developed explicit integration algorithms and compared with several commonly-used prediction procedures. The evaluation of its prediction accuracy is carried out theoretically, numerically and experimentally. Results indicate that the accuracy and effectiveness of the proposed prediction method are of significance.

Actuator Failure Compensation Control Scheme of the Nonlinear Triangular Systems by Static Gain Technique

Fei Zhu,Xian-Fu Zhang,Hanfeng Li 제어·로봇·시스템학회 2020 International Journal of Control, Automation, and Vol.18 No.9

In this paper, the technique of static gain as a new research approach is applied in the nonlinear triangular systems to investigate the issue of actuator fault. By employing the static gain technique, the nonlinear lowertriangular systems are converted into the form which is easy to find its Lyapunov function. The fault parameters of the actuator are subsequently processed by the efficient adaptive estimation tactic, after that, the goal of guaranteeing the global boundness of all closed-loop signals can be achieved by utilizing a state controller with the hyperbolicfunctions. Moreover, by adopting the same strategy, the actuator failure compensation problem is also solved for the nonlinear upper-triangular systems. Last but not least, the effectiveness of the design scheme is verified by two numerical simulation examples.

Analysis of delay compensation in real-time dynamic hybrid testing with large integration time-step

Zhu, Fei,Wang, Jin-Ting,Jin, Feng,Gui, Yao,Zhou, Meng-Xia Techno-Press 2014 Smart Structures and Systems, An International Jou Vol.14 No.6

With the sub-stepping technique, the numerical analysis in real-time dynamic hybrid testing is split into the response analysis and signal generation tasks. Two target computers that operate in real-time may be assigned to implement these two tasks, respectively, for fully extending the simulation scale of the numerical substructure. In this case, the integration time-step of solving the dynamic response of the numerical substructure can be dozens of times bigger than the sampling time-step of the controller. The time delay between the real and desired feedback forces becomes more striking, which challenges the well-developed delay compensation methods in real-time dynamic hybrid testing. This paper focuses on displacement prediction and force correction for delay compensation in the real-time dynamic hybrid testing with a large integration time-step. A new displacement prediction scheme is proposed based on recently-developed explicit integration algorithms and compared with several commonly-used prediction procedures. The evaluation of its prediction accuracy is carried out theoretically, numerically and experimentally. Results indicate that the accuracy and effectiveness of the proposed prediction method are of significance.

Robust Inland Waterway Ship Tracking via Orthogonal Particle Filter-based Predator

Fei Teng,Qing Liu,Lin Zhu 보안공학연구지원센터(IJSIP) 2014 International Journal of Signal Processing, Image Vol.7 No.6

Tracking-Learning-Detection (TLD), also known as Predator, has become one of the most popular state-of-the-art algorithms in the domain of visual tracking in recent years. It has demonstrated outstanding performance in the application of long-term tracking of a human face in unconstrained videos. In this paper, we address the problem of tracking a single ship in inland waterway CCTV videos given its location in the first frame and no other prior information. Firstly, we deeply analyze Predator in a perspective of control system and point out the search strategy in detection procedure is the most time-consuming part in Predator system. Secondly, in order to speed up the whole pipeline, we propose a novel motion model based on extended particle filter with orthogonal design. Due to the power of particle optimization and re-combination with orthogonal design, we can relate the motion of object of interest better and obtain the most likely candidates of object regions more effectively. Finally, both qualitative and quantitative evaluations on numerous challenging CCTV videos demonstrate that the proposed algorithm achieves favorable performance in terms of efficiency and accuracy.

Prevalence and Risk Factors of Cerebral Small Vessel Disease in a Chinese Population-Based Sample

Fei Han,Fei-Fei Zhai,Quan Wang,Li-Xin Zhou,Jun Ni,Ming Yao,Ming-Li Li,Shu-Yang Zhang,Li-Ying Cui,Zheng-Yu Jin,Yi-Cheng Zhu 대한뇌졸중학회 2018 Journal of stroke Vol.20 No.2

Background and Purpose Epidemiological data of cerebral small vessel disease (CSVD) in the general population of China are lacking. We report on the prevalence of lacunes, white matter hyperintensity (WMH), and cerebral microbleeds (CMBs) in a community-based sample in China and compare the results with those of other studies. Methods This was a cross-sectional analysis of the population-based Shunyi Study in China. A total of 1,211 stroke-free participants (mean age, 55.6±9.3 years; 37.4% men) with available 3 Tesla (3T) magnetic resonance images were included in this analysis. Demographic information and risk factor data were assessed. The overall and age-specific prevalence of lacunes, WMH, and CMBs was evaluated. Associations between cardiovascular risk factors and the presence of these lesions were analyzed by multiple logistic regression. Results Our study showed a prevalence of 14.5% for lacunes, 72.1% for periventricular hyperintensity (PVH), 65.4% for deep white matter hyperintensity (DWMH), and 10.6% for CMBs. When compared with other community-based samples, individuals in the same age group showed a higher burden of lacunes and a relatively lower prevalence of CMBs. Advanced age was independently associated with the prevalence of these CSVD markers, while the presence of hypertension increased the risk of lacunes, PVH/DWMH, and CMBs in deep or infratentorial locations. Conclusions A higher burden of lacunes but a relatively lower prevalence of CMBs was observed in this Chinese population. This notable result highlights the challenge of CSVD prevention in China. Chinese have a risk factor profile for CSVD similar to those in other populations.

Suppression of Cellular Apoptosis Susceptibility (CSE1L) Inhibits Proliferation and Induces Apoptosis in Colorectal Cancer Cells

Zhu, Jin-Hui,Hong, De-Fei,Song, Yong-Mao,Sun, Li-Feng,Wang, Zhi-Fei,Wang, Jian-Wei Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.2

The cellular apoptosis susceptibility (CSE1L) gene has been demonstrated to regulate multiple cellular mechanisms including the mitotic spindle check point as well as proliferation and apoptosis. However, the importance of CSE1L in human colon cancer is largely unknown. In the present study, we examined expression levels of CSE1L mRNA by semiquantitative RT-PCR. A lentivirus-mediated small interfering RNA (siRNA) was used to knock down CSE1L expression in the human colon cancer cell line RKO. Changes in CSE1L target gene expression were determined by RT-PCR. Cell proliferation was examined by a high content screening assay. In vitro tumorigenesis was measured by colony-formation assay. Cell cycle distribution and apoptosis were detected by flow cytometric analysis. We found CSE1L mRNA to be expressed in human colon cancer cells. Using a lentivirus based RNAi approach, CSE1L expression was significantly inhibited in RKO cells, causing cell cycle arrest in the G2/M and S phases and a delay in cell proliferation, as well as induction of apoptosis and an inhibition of colony growth capacity. Collectively, the results suggest that silencing of CSE1L may be a potential therapeutic approach for colon cancer.

Probabilistic multiscale modeling of 3D randomly oriented and aligned wavy CNT nanocomposites and RVE size determination

Zhu, Fei-Yan,Jeong, Sungwoo,Lim, Hyoung Jun,Yun, Gun Jin Elsevier 2018 Composite structures Vol.195 No.-

<P><B>Abstract</B></P> <P>This paper presents a probabilistic multiscale approach to model the random spatial distribution of local elastic properties arising from the heterogeneous waviness and orientation of CNT fillers within a 3D microscale continuum representative volume element (RVE) of a CNT-reinforced polymer matrix. The proposed direction-sensitive 3D Karhunen-Loève expansion (KLE) provides the basis to simulate stochastic variations in the CNT orientations rather than assuming a perfect alignment. Computational homogenization analyses are carried out to investigate the effects of the statistical parameters of random CNT waviness on the microscale continuum RVE size. The proposed probabilistic multiscale modelling framework allows to consider the uncertainty associated with the use of CNT nanocomposites for various applications.</P>

Comparison of the chromatographic analysis of Bisphenol A in various water qualities

( Fei Die Zhu ),( Hyun Shik Chang ),( Kwang Ho Choo ),( Sang Jung Choi ),( Byung Hwan Lee ) 한국물환경학회 ( 구 한국수질보전학회 ) 2008 한국물환경학회·대한상하수도학회 공동 춘계학술발표회 Vol.2008 No.-

Component-based model for posttensioned steel connections against progressive collapse

Yan Fei Zhu,Chang Hong Chen,Ying Huang,Zhaohui Huang,Yao Yao,Leon M. Keer 국제구조공학회 2021 Steel and Composite Structures, An International J Vol.40 No.4

A component-based method for the estimation of the posttensioned (PT) steel frame against progressive collapse is proposed and presented in the current paper. A mechanical model of PT steel connections is developed and benchmarked with experimental data of a PT beam-column substructure from literature. The developd mechanical models of four PT connections are able to capture the initial elastic stiffness, decompression load, and residual stiffness under lateral loading. Then, analysis of a reduced-scale three-storey two-bay PT steel frame is carried out with sufficient accuracy by incorporating the proposed joint model into the frame analysis. The proposed method is then applied to assessing progressive collapse of a one-storey two-bay PT frame under middle column removal scenario, and is verified against existing experimental and ANSYS finite element results. Three resistance mechanism for progressive collapse of the PT frame are evaluated, which consists of angle flexural mechanism, beam compression arching action and strand tensile catenary action. Finally, parameter analyses of the PT frames are conducted to investigate the effects of the connection details on the behavior and resistance of progressive collapse. The proposed model can be used to predict the quasi-static behavior of PT frames under monotonic vertical loading conditions with satisfactory accuracy.

Dynamic increase factor for progressive collapse analysis of semi-rigid steel frames

Yan Fei Zhu,Chang Hong Chen,Yao Yao,Leon M. Keer,Ying Huang 국제구조공학회 2018 Steel and Composite Structures, An International J Vol.28 No.2

An empirical and efficient method is presented for calculating the dynamic increase factor to amplify the applied loads on the affected bays of a steel frame structure with semi-rigid connections. The nonlinear static alternate path analysis is used to evaluate the dynamic responses. First, the polynomial models of the extended end plate and the top and seat connection are modified, and the proposed polynomial model of the flush end plate connection shows good agreement as compared with experimental results. Next, a beam model with nonlinear spring elements and plastic hinges is utilized to incorporate the combined effect of connection flexibility and material nonlinearity. A new step-by-step analysis procedure is established to obtain quickly the dynamic increase factor based on a combination of the pushdown analysis and nonlinear dynamic analysis. Finally, the modified dynamic increase factor equation, defined as a function of the maximum ratio value of energy demand to energy capacity of an affected beam, is derived by curve fitting data points generated by the different analysis cases with different column removal scenarios and five types of semi-rigid connections.