Observer-based Fixed-time Fuzzy Adaptive Output Feedback Tracking Control for a Class of Nonlinear Systems

Yujing Shi,Chen Wang,Shanqiang Li 제어·로봇·시스템학회 2022 International Journal of Control, Automation, and Vol.20 No.8

This paper is concerned with the fixed-time tracking control problem for a class of uncertain strictfeedback nonlinear systems with external disturbances and unmeasured states. The fuzzy state observer and fuzzy logic systems (FLSs) are adopted to estimate the unmeasurable states and approximate the unknown nonlinear functions, respectively. To improve the performance of the system, we attempt to introduce a disturbance observer into the design of the controller. A first-order filter is applied to avoid the computational complexity problem in the backstepping scheme. Subsequently, the fixed-time stability of the closed-loop system is guaranteed in the light of the Lyapunov stability theory, and the tracking error can converge to an adjustable domain under the proposed control method. Compared with the existing finite-time control strategy, the settling time of the presented fixed-time control scheme is unrelated to the initial conditions of the system. Finally, two simulation experiments are given to illustrate the effectiveness of the developed control approach.

State Feedback Design for Nonlinear Quadratic Systems with Randomly Occurring Actuator Saturation

Yujing Shi,Yueru Li,Shanqiang Li,Hongyu Liu 제어·로봇·시스템학회 2017 International Journal of Control, Automation, and Vol.15 No.3

This paper is concerned with the problem of state feedback control for nonlinear quadratic systemswith randomly occurring actuator saturation. The considered actuator saturation is assumed to occur in a randomway, and the randomly occurring rates of the saturation are time-varying with known upper and lower bounds. Byusing the Lyapunov approach, a sufficient condition is given to guarantee that the closed-loop system is locallyasymptotically stable in mean-square sense. The desired controller gain can be obtained in terms of the solutionsto certain linear matrix inequalities. Finally, a simulation example is provided to show the effectiveness of theproposed control scheme.

女仕牌固体饮料对左甲状腺素钠诱导肾阴虚小鼠模型内分泌系统的影响

류석(刘硕),마사요(马思遥),주문이(朱文驿),양가(梁佳),Yujing Shi,Hong Meng 한국피부과학연구원 2020 아시안뷰티화장품학술지 Vol.18 No.2

Purpose: To observe the effects of Nv Shi solid drink on thyroid hormone, sex hormones and cyclic nucleotide of kidney-yin deficiency hyperthyroid mice induced by levothyroxine sodium. Methods: ICR mice were randomly grouped into normal control group, model group, Nv Shi solid drink high dose group, the middle dose group and low dose group, male and female in half. The kidney-yin deficiency mice models were established by intragastric administration of levothyroxine sodium before intragastric administration of corresponding drugs once a day for 10 consecutive days. One day after the last administration, the effects were observed by measuring weight. And tetraiodothyronine (T4), triiodothyronine (T3), thyrotropin (TSH), testosterone (T), estradiol (E2), cyclic adenosine monophosphate (cAMP), cyclic guanosine monophosphate (cGMP) were tested by ELISA method. Results: Compared with the model group, the body weight increased significantly (p<0.05), T3 level decreased significantly in high and medium dose group (p<0.01, p<0.05), and serum T4 and cAMP decreased significantly (p<0.01, p<0.05), TSH increased significantly (p<0.01, p<0.05) in all dose groups, and cAMP/cGMP decreased in the low dose group (p<0.05). The expression of E2 in female decreased significantly in all does groups, the same as the ratio of E2/T in high dose group (p<0.05). There was no significant change in the expression of sex hormones in male in all dose groups (p>0.05). Conclusion: Nv Shi solid drink may improve the kidney-yin deficiency syndrome by adjusting T3, T4, TSH, cAMP and E2 level in the endocrine system of the body and exert the function of nourishing yin and tonifying kidney. 目的: 观察女仕牌固体饮料对左甲状腺素钠致肾阴虚模型小鼠体内甲状腺激素、性激素及环核苷酸的影响。方 法: ICR小鼠随机分为正常组、模型组、女仕牌固体饮料大、中、小剂量组,雌雄各半,采用左甲状腺素钠片灌 胃造成小鼠肾阴虚模型,造模当天灌胃给予样品,每天1次,连续10天。末次给药后1天,观察小鼠体征及体 重,取血,采用Elisa方法检测血清中甲状腺素(thyroxine, T4)、三碘甲状原氨酸(triiodothyronine, T3)、 促甲状腺激素(thyroid-stimulating hormone, TSH)、睾酮(testosterone, T)、雌二醇(estradiol, E2)、 环磷酸腺苷(cyclic Adenosine monophosphate, cAMP)、环磷酸鸟苷(cyclic guanosine monophosphate, cGMP)的表达。结果: 与模型组比较,女仕牌固体饮料大剂量组和中剂量组小鼠体重显著升高(p<0.05);大 剂量和中剂量组T3显著降低(p<0.01,p<0.05),各剂量组血清T4、cAMP均显著降低(p<0.01,p<0.05), TSH均显著升高(p<0.01,p<0.05),小剂量组cAMP/ cGMP比值降低(p<0.05),各剂量组雌鼠E2表达显著 降低,大剂量组雌鼠E2/T比值降低,各剂量组雄鼠性激素表达无显著改变(p>0.05)。结论: 女仕牌固体饮料 可能通过调整机体内神经分泌系统中T3、T4、TSH、cAMP、雌鼠E2这些共同的潜在物质基础,改善HPT轴和 HPG轴功能、平衡环核苷酸系统,从而改善肾阴虚证,发挥滋阴补肾功效。

Acoustic-based Classification for Drone Identification using Support Vector Machine with Harmonic Line Association Technique

Yujing He,Lin Shi,KyungHi Chang 한국통신학회 2016 한국통신학회 학술대회논문집 Vol.2016 No.6

SVM-based Drone Sound Recognition using the Combination of HLA and WPT Techniques in Practical Noisy Environment

( Yujing He ),( Ishtiaq Ahmad ),( Lin Shi ),( Kyunghi Chang ) 한국인터넷정보학회 2019 KSII Transactions on Internet and Information Syst Vol.13 No.10

In recent years, the development of drone technologies has promoted the widespread commercial application of drones. However, the ability of drone to carry explosives and other destructive materials may bring serious threats to public safety. In order to reduce these threats from illegal drones, acoustic feature extraction and classification technologies are introduced for drone sound identification. In this paper, we introduce the acoustic feature vector extraction method of harmonic line association (HLA), and subband power feature extraction based on wavelet packet transform (WPT). We propose a feature vector extraction method based on combined HLA and WPT to extract more sophisticated characteristics of sound. Moreover, to identify drone sounds, support vector machine (SVM) classification with the optimized parameter by genetic algorithm (GA) is employed based on the extracted feature vector. Four drones’ sounds and other kinds of sounds existing in outdoor environment are used to evaluate the performance of the proposed method. The experimental results show that with the proposed method, identification probability can achieve up to 100 % in trials, and robustness against noise is also significantly improved.

Hidden Markov model based drone sound recognition using MFCC technique in practical noisy environments

Shi, Lin,Ahmad, Ishtiaq,He, YuJing,Chang, KyungHi Editorial Department of Journal of Communications 2018 Journal of communications and networks Vol.20 No.5

<P>The development of drones has captured the attention of hobbyists and investors alike; drones now have greater commercial and military applications owing to their relatively small size and ability to fly without an on-board pilot. However, certain drone applications may pose serious threats to public safety. The most important problem to be addressed is the recognition of drones in security-sensitive areas. This paper presents an approach to recognize drones through sounds emitted by their propellers using Mel frequency cepstral coefficients (MFCCs) technique for feature extraction and the hidden Markov model (HMM) approach for classification. In the feature extraction stage, two schemes for feature vectors (one using twenty-four MFCCs and the other using the proposed thirty-six MFCCs) are applied, where additional dynamic information of the features is added in the latter. The classifier based on HMMs is then trained using the extracted features according to different training datasets in order to validate the effect of the number of sound types in each cluster on the recognition rate performance. We perform experiments for drone sound recognition utilizing various training datasets for the purpose of classifier optimization, as well as for the two MFCC schemes that are applied in each trial, using the same training datasets for a fair comparison. The experimental results finally validate the feasibility and effectiveness of our proposed methods with relatively high recognition rates, even in noisy environments.</P>

Study on Calculation Method of D-Axis Super-Transient Reactance of Damped Winding Permanent Magnet Electrical Machine

Yujing Guo,Bin Shi,Ping Jin 한국자기학회 2023 Journal of Magnetics Vol.28 No.4

Dynamic parameters directly reflect the dynamic performance of electrical machines. In this paper, two methods for calculating the d-axis super-transient reactance of a damped winding permanent magnet electrical machine (DWPMEM) are proposed. One is the analytical method: the analytical model of d-axis super-transient reactance is developed, and the d-axis super-transient reactance is calculated by taking the coupling of permanent magnet (PM) and winding current magnetic field into account. The other is the parameter identification method: the parameter identification model of DWPMEM is established, and the reactance is identified based on the DC step voltage method. The calculation accuracy of the two methods is verified by the measured data, and the variation rules of the d-axis super-transient reactance with damping winding structures are analyzed. The work of this paper has a certain reference value for the design and dynamic operation evaluation of DWPMEM.

Growth and potential collapse of the lava dome in Unzen volcano and the estimation on block-and-ash flows

Xiao Shi,Yujing Jiang,Yasuyuki Hirakawa 한국지질과학협의회 2018 Geosciences Journal Vol.22 No.2

Heisei lava dome was formed in Unzen volcano over the period from 1991 to 1995. The recent continuous observations have shown that the lava dome is still growing, which is a threat for the life of the nearby residents. How to estimate the range of collapse and potential block-and-ash flows is an urgent problem. Airborne laser scanning method is briefly introduced. We presented a division to separate the lava dome with 10 potential collapsed blocks and set some measuring points to observe the elevation change in each block. By analyzing the elevation decrease from 2003 to 2014, the potential collapsed blocks that experienced obvious changes were identified. With the evaluation of elevation changes by airborne laser data, the buried terrain of dome was reconstructed. The results show that the whole lava dome from lobe 1 to 11 may collapse, and the potential maximum volume of collapsed part is 1.46 × 107 m3. If the collapsed part forms block-and-ash flow, the flow will arrive at the seaside in approximately 7 minutes according to the result of simulation. The flow could travel approximately 8.5 km, and the average velocity is approximately 20 m/s.

Acoustic-based Classification for Drone Identification using Hidden Markov Model with MFCC Technique

Lin Shi,Yujing He,KyungHi Chang 한국통신학회 2016 한국통신학회 학술대회논문집 Vol.2016 No.6

Calcined Attapulgite Clay as Supplementary Cementing Material: Thermal Treatment, Hydration Activity and Mechanical Properties

Tao Shi,Yanming Liu,Yanlin Zhang,Yingjia Lan,Qifan Zhao,Yujing Zhao,Haobo Wang 한국콘크리트학회 2022 International Journal of Concrete Structures and M Vol.16 No.2

The present paper studied the effects of calcination temperatures (200–800 °C) on the appearance, mineral composition, and active SiO2 content in attapulgite and investigated the effects of attapulgite before and after calcination on the chemically bonded water content, the degree of reaction of cement paste, and the mechanical properties such as the flexural strength, compressive strength, and splitting-tensile strength of cement mortar. The results indicate that the calcination temperature changes the mineral composition of attapulgite, thereby affecting the hydration activity of cement-based materials. The attapulgite calcined at 500 °C (AT500) has the best enhancement on the hydration activity of cement-based materials. The calcination at 500 °C is most beneficial to the dissolution of SiO2, and the content of SiO2 reaches 20.96%. The contents of chemically bonded water in the samples incorporated with calcined attapulgite reduced and that of the samples incorporated with AT500 at 28 d is the same as that of the control group. The reaction degree of AT500 is 78.61% at 28 days. Calcined attapulgite clay can reduce the energy consumption of the cement industry and promote the sustainable development of attapulgite clay.