Fault Detection and Diagnosis for Delay-Range-Dependent Stochastic Systems Using Output PDFs

Liping Yin,Pengwei Zhu,Tao Li 제어·로봇·시스템학회 2017 International Journal of Control, Automation, and Vol.15 No.4

This paper investigates a new fault detection and diagnosis(FDD) scheme for delay-range-dependentstochastic systems. Compared with classical FDD problem, the measurable information in this paper is supposedto be the output probability density function(PDF), rather than the output itself. By using the square root B-splineapproximation technique, the dynamic weight model of the output PDFs is established and the considered problemis converted into a nonlinear FDD problem for stochastic systems with delays. The main objective of this paper isto construct a filter based residual generator such that the fault can be detected and estimated. The FDD criteria isprovided on the basis of linear matrix inequalities(LMIs). Besides, to improve the FDD performance, the tuningparameters, slack variables as well as the free-weighting matrices are applied to optimize the FDD criteria. Finally,the simulations are given to demonstrate the effectiveness of the proposed method.

Effect of cohesive powders on pressure fluctuation characteristics of a binary gas-solid fluidized bed

Liping Wei,Youjun Lu,Jianbo Zhu,Guodong Jiang,Jun Hu,Haipeng Teng 한국화학공학회 2018 Korean Journal of Chemical Engineering Vol.35 No.10

The effect of cohesive particles on the pressure fluctuations was experimentally investigated in a binary gassolid fluidized bed. The pressure fluctuation signals were measured by differential pressure sensors under conditions of various weight percentages of cohesive particles. The cohesive particles increased the fixed bed pressure drop per unit height and decreased the minimum fluidization velocity. The Wen & Yu equation well predicts the minimum fluidization velocity of the binary system. The addition of cohesive particles slightly decreased the bubble size in bubbling flow regime when the cohesive particles and the coarse particles mixed well, while the bubble size greatly decreased when the cohesive particles agglomerated on the bed surface. The time series of pressure fluctuations was analyzed by using the methods of time domain, frequency domain and wavelet transformation. The normalized standard deviation of pressure fluctuations decreased with increasing weight percentages of cohesive particles. A wide bandwidth frequency of 0 to 1Hz got narrower with a single peak around 0.6Hz with an increase in proportion of the cohesive particles. The meso-energy and micro-energy of pressure fluctuations were decreasing with increasing cohesive particles proportions, which indicated that adding cohesive particles could reduce the energy dissipation of bubble and particle fluctuations.

Guaranteed Cost Consensus for a Class of Fractional-order Uncertain Multi-agent Systems with State Time Delay

Liping Chen,Xiaomin Li,Xiang Li,Min Zhu,Ranchao Wu,António M. Lopes 제어·로봇·시스템학회 2022 International Journal of Control, Automation, and Vol.20 No.11

This work investigates the guaranteed cost leader-following consensus of a class of uncertain fractionalorder (FO) multi-agent systems (FOMASs) affected by state time delay. The leader and following group are exposed to norm-bounded time-varying parametric uncertainty and time-delay. A delay- and order-dependent consensus protocol is developed which guarantees robust stability of the controlled system and ensures that the effect of uncertainty on the system performance is below some prescribed index. The FO Razumikhin theorem and the linear matrix inequality approach are adopted to derive the method that can be applied to FOMASs with deterministic parameters. The analysis can be extended to distinct consensus problems for different types of FOMASs. Three numerical examples illustrate the effectiveness and feasibility of the approach.

Coupled Orbit-attitude Saturated Control for Solar Sail in Earth-Moon 3-body System

Liping Wu,Yu Guo,Zhihao Zhu 제어·로봇·시스템학회 2021 International Journal of Control, Automation, and Vol.19 No.11

This paper aims to investigate a coupled orbit-attitude control strategy for a kind of novel spacecraft, solar sail, to track the given orbit in Earth-Moon 3-Body dynamic environment in presence of the matched and mismatched disturbances, attitude control saturation, orbital modeling error and parametric uncertainties. A cascaded triple-loop control structure is proposed to deal with the strong couplings between the orbit and attitude systems. The inner loop focusing on the orbital effects on attitude dynamics, an adaptive saturation controller is proposed to achieve attitude angular tracking, where the uncertain inertia, unknown matched disturbance and saturated attitude control torque are compensated by combining the unknown knowledge. The middle loop is to handle the orbit effects on attitude kinematics facing the mismatched disturbance. In the outer loop, the effects of attitude systemon orbit dynamics are deal with, where an adaptive orbit controller is designed considering the uncertain optical parameter and orbital modeling error. The proposed control structure efficiently simplifies the coupled orbit-attitudecontrol design for solar sail. In contrast to traditional coupled controllers for solar sail, the proposed control laws do not require exact knowledge of parametric uncertainties, disturbances and orbit modeling errors. The combination of unknown information reduces the number of estimated parameters as well. The numerical simulation results demonstrate the effectiveness of the proposed control strategy.

Effects of weight on bit on torsional stick-slip vibration of oilwell drill string

Liping Tang,Xiaohua Zhu,Xudong Qian,Changshuai Shi 대한기계학회 2017 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.31 No.10

The stick-slip phenomenon is a type of dysfunction detrimental to the drilling operation. Field application shows that stick-slip phenomenon is inclined to appear when using a large Weight on bit (WOB). In this paper, effects of the WOB on the stick-slip vibration are investigated. Based on a lumped torsional pendulum model of the drilling system, equation of motion of the drill bit is obtained. By using parameters commonly used in field applications, the bit dynamics are analyzed and the stick-slip vibrations are discussed. During the stick-slip motions, the negative damping effect occurs in the transition from the stick phase to the slip phase. With the increasing WOB, the bit behavior may change from the stable motion to the stick-slip vibration once the WOB reaches the critical value. In case of stickslip vibration, the phase trajectory ultimately converges to a limit cycle which represents periodical bit motion. With increases in the WOB, the limit cycle enlarges. For cases without stick-slip vibrations, the drill bit vibrates damply and finally converges to a state of uniform motion. The results presented in this paper can be applied to interpret some of the field phenomena related to WOB.

MicroRNA-576-3p Inhibits Proliferation in Bladder Cancer Cells by Targeting Cyclin D1

Liping Xie,Zhen Liang,Shiqi Li,Xin Xu,Xianglai Xu,Xiao Wang,Jian Wu,Yi Zhu,Zhenghui Hu,Yiwei Lin,Yeqing Mao,Hong Chen,Jindan Luo,Ben Liu,Xiangyi Zheng 한국분자세포생물학회 2015 Molecules and cells Vol.38 No.2

MicroRNAs (miRNAs) are small, endogenous RNAs that play important gene-regulatory roles by binding to the imperfectly complementary sequences at the 3 -UTR of mRNAs and directing their gene expression. Here, we first discovered that miR-576-3p was down-regulated in human bladder cancer cell lines compared with the non-malignant cell line. To better characterize the role of miR-576-3p in bladder cancer cells, we over-expressed or down-regulated miR-576-3p in bladder cancer cells by transfecting with chemically synthesized mimic or inhibitor. The overexpression of miR-576-3p remarkably inhibited cell proliferation via G1-phase arrest, and decreased both mRNA and protein levels of cyclin D1 which played a key role in G1/S phase transition. The knock-down of miR-576-3p significantly promoted the proliferation of bladder cancer cells by accelerating the progression of cell cycle and increased the expression of cyclin D1. Moreover, the dual-luciferase reporter assays indicated that miR-576-3p could directly target cyclin D1 through binding its 3 -UTR. All the results demonstrated that miR-576-3p might be a novel suppressor of bladder cancer cell proliferation through targeting cyclin D1.

Effect of Perforating an Intake Pipe on the Interior Noise of a Passenger Car

Zhu Yawei,Lu Chihua,Liu Zhien,Xie Liping,Li Xiaolong 한국자동차공학회 2021 International journal of automotive technology Vol.22 No.4

The intake pipes designed by some experienced engineers have small holes. However, the role of these small holes is yet to be fully understood by most engineers. At present, the only research on this issue is also controversial. This work aims to reveal the effect of perforating an intake pipe on the interior noise and provide some suggestions to automotive engineers when applying this method. First, the effect of these small holes on the source strength of the intake nozzle and perforated region is theoretically analyzed. Thereafter, the noise transfer functions of the intake nozzle and perforated region to the target response point in the cab are measured on the basis of the reciprocity principle. Finally, the effect of perforating the intake pipe on the interior noise is studied by simulating the intake noise of the experimental car with an external sound source. Results show that perforating the intake pipe can increase the order noise component of the intake noise and reduce the mid-high frequency noise in the cab, thereby improving the powerful sound quality and reducing the feeling of noisy.

Phosphorylated gelatin to enhance cell adhesion to titanium

박신혜,Liping Zhu,Seiichi Tada,Satoshi Tsuneda,Yoshihiro Ito 한국고분자학회 2014 한국고분자학회 학술대회 연구논문 초록집 Vol.2014 No.10

Lossless Compression for Hyperspectral Images based on Adaptive Band Selection and Adaptive Predictor Selection

( Fuquan Zhu ),( Huajun Wang ),( Liping Yang ),( Changguo Li ),( Sen Wang ) 한국인터넷정보학회 2020 KSII Transactions on Internet and Information Syst Vol.14 No.8

With the wide application of hyperspectral images, it becomes more and more important to compress hyperspectral images. Conventional recursive least squares (CRLS) algorithm has great potentiality in lossless compression for hyperspectral images. The prediction accuracy of CRLS is closely related to the correlations between the reference bands and the current band, and the similarity between pixels in prediction context. According to this characteristic, we present an improved CRLS with adaptive band selection and adaptive predictor selection (CRLS-ABS-APS). Firstly, a spectral vector correlation coefficient-based k-means clustering algorithm is employed to generate clustering map. Afterwards, an adaptive band selection strategy based on inter-spectral correlation coefficient is adopted to select the reference bands for each band. Then, an adaptive predictor selection strategy based on clustering map is adopted to select the optimal CRLS predictor for each pixel. In addition, a double snake scan mode is used to further improve the similarity of prediction context, and a recursive average estimation method is used to accelerate the local average calculation. Finally, the prediction residuals are entropy encoded by arithmetic encoder. Experiments on the Airborne Visible Infrared Imaging Spectrometer (AVIRIS) 2006 data set show that the CRLS-ABS-APS achieves average bit rates of 3.28 bpp, 5.55 bpp and 2.39 bpp on the three subsets, respectively. The results indicate that the CRLS-ABS-APS effectively improves the compression effect with lower computation complexity, and outperforms to the current state-of-the-art methods.

The Investigation of Internal Coating for Natural Gas Pipeline

Lin, Zhu,Zhang, Liping,Qin, Yanlong,Zhang, Qibin 한국부식방식학회 2002 Corrosion Science and Technology Vol.31 No.5

Internal coating applied on natural gas pipeline not only can prevent the pipelines fiom internal corrosion, but also can greatly decrease the roughness of internal surface of the pipeline so that the gas flowing resistance would be reduced and the gas transmission efficiency could be improved largely. In order to meet with the requirement of western gas pipeline projects, a internal coating material special for reducing transmission resistance of gas pipeline has been developed by my Institute. A stimulating test equipment showthat transmission efficiency of pipe with special internal coating can be 15.3% more than that of steel pipe without coating.