Output-Feedback Control of a Class of Stochastic Nonlinear Systems with Power Growth Conditions

Long-Chuan Guo,Xin Zuo,Hua-Qing Liang,Jian-Wei Liu 제어·로봇·시스템학회 2014 International Journal of Control, Automation, and Vol.12 No.2

This paper investigates the problem of output-feedback stabilization for a class of stochastic nonlinear systems in which the nonlinear terms depend on unmeasurable states besides measurable input. We extend linear growth conditions to power growth conditions and reduce the control effort. By using backstepping technique, choosing a high-gain parameter, an output-feedback controller is designed to ensure the closed-loop system globally asymptotically stable in probability. The efficiency of the output-feedback controller is demonstrated by a simulation example.

Physical properties and chemical composition of the cores in the California molecular cloud

Zhang, Guo-Yin,Xu, Jin-Long,Vasyunin, A. I.,Semenov, D. A.,Wang, Jun-Jie,Dib, Sami,Liu, Tie,Liu, Sheng-Yuan,Zhang, Chuan-Peng,Liu, Xiao-Lan,Wang, Ke,Li, Di,Wu, Zhong-Zu,Yuan, Jing-Hua,Li, Da-Lei,Gao, Springer-Verlag 2018 Astronomy and astrophysics Vol.620 No.-

<P><I>Aims.</I> We aim to reveal the physical properties and chemical composition of the cores in the California molecular cloud (CMC), so as to better understand the initial conditions of star formation.</P><P><I>Methods.</I> We made a high-resolution column density map (18.2′′) with <I>Herschel</I> data, and extracted a complete sample of the cores in the CMC with the fellwalker algorithm. We performed new single-pointing observations of molecular lines near 90 GHz with the IRAM 30m telescope along the main filament of the CMC. In addition, we also performed a numerical modeling of chemical evolution for the cores under the physical conditions.</P><P><I>Results.</I> We extracted 300 cores, of which 33 are protostellar and 267 are starless cores. About 51% (137 of 267) of the starless cores are prestellar cores. Three cores have the potential to evolve into high-mass stars. The prestellar core mass function (CMF) can be well fit by a log-normal form. The high-mass end of the prestellar CMF shows a power-law form with an index <I>α</I> = −0.9 ± 0.1 that is shallower than that of the Galactic field stellar mass function. Combining the mass transformation efficiency (<I>ε</I>) from the prestellar core to the star of 15 ± 1% and the core formation efficiency (CFE) of 5.5%, we suggest an overall star formation efficiency of about 1% in the CMC. In the single-pointing observations with the IRAM 30m telescope, we find that 6 cores show blue-skewed profile, while 4 cores show red-skewed profile. [HCO<SUP>+</SUP>]/[HNC] and [HCO<SUP>+</SUP>]/[N2H<SUP>+</SUP>] in protostellar cores are higher than those in prestellar cores; this can be used as chemical clocks. The best-fit chemical age of the cores with line observations is ~5 × 10<SUP>4</SUP> yr.</P>

Improving the quality of breast ultrasound examination performed by inexperienced ultrasound doctors with synchronous tele-ultrasound: a prospective, parallel controlled trial

Yi-Kang Sun,Xiao-Long Li,Qiao Wang,Bo-Yang Zhou,An-Qi Zhu,Chuan Qin,Le-Hang Guo,Hui-Xiong Xu 대한초음파의학회 2022 ULTRASONOGRAPHY Vol.41 No.2

Purpose: This prospective study explored the value of synchronous tele-ultrasound (US) to aid doctors inexperienced in US with breast US examinations.Methods: In total, 99 patients were enrolled. Two trainee doctors who were inexperienced in US (trainee A [TA] and trainee B [TB]) and one doctor who was an expert in US completed the US examinations sequentially. TA completed the US examinations independently, while TB was instructed by the expert using synchronous tele-US. Subsequently, the expert performed on-site US examinations in person. Separately, they selected the most clinically significant nodule as the target nodule. Consistency with the expert and image quality were compared between TA and TB to evaluate tele-US. Furthermore, TB and the patients evaluated tele-US through questionnaires.Results: TB demonstrated higher consistency with the expert in terms of target nodule selection than TA (93.3% vs. 63.3%, P<0.001). TB achieved good inter-observer agreement (ICC, >0.75) with the expert on five US features (5/9, 55.6%), while TA only did so for one (1/9, 11.1%) (P=0.046). TB’s image quality was higher than TA’s in gray value, time gain compensation, depth, color Doppler adjustment, and the visibility of key information (P=0.018, P<0.001, P<0.001, P=0.033, and P=0.006, respectively). The comprehensive assessment score was higher for TB than for TA (3.96±0.82 vs. 3.09±0.87, P<0.001). Tele-US was helpful in 69.7% of US examinations and had a training effect in 68.0%. Furthermore, 63.6% of patients accepted tele-US and 60.6% were willing to pay.Conclusion: Tele-US can help doctors inexperienced in US to perform breast US examinations.

Active Shimmy Control Method for Driverless Electric Vehicle Considering Unknown Sensor Measurement Error and Nonlinearities

Qinghua Meng,Heyang Zheng,Long-chuan Guo,Chih-Chiang Chen,Zong-Yao Sun,Chuan Hu 제어·로봇·시스템학회 2023 International Journal of Control, Automation, and Vol.21 No.7

The driverless electric vehicle with electric wheels may generate the front wheel shimmy phenomenon more easily. How to mitigate or even eliminate the shimmy phenomenon by active control method is necessary. The current active shimmy control methods do not consider the sensor measurement error. But the sensor measurement error always exists in practice because of sensor design, manufacturing, and external disturbances. Therefore, this paper investigates this issue. Firstly, a one-degree-of-freedom shimmy model of the front wheel is built. The dynamic function of this model is obtained via Lagrange’s theorem. Then, the shimmy control system with unknown sensor measurement error and nonlinearities is presented. A dual domination control method is proposed to construct a linear state observer as well as an output feedback control law for the shimmy control system. By the Lyapunov method, the designed controller is proved to stabilize the shimmy system globally asymptotically. Finally, simulations are carried out to verify the effectiveness of the one-degree-of-freedom shimmy model and proposed dual domination control method.

Clinicopathological Features and Immunohistochemical Alterations of Keratinocyte Proliferation, Melanocyte Density, Smooth Muscle Hyperplasia and Nerve Fiber Distribution in Becker`s Nevus

( Ping Sheng ),( Yun-long Cheng ),( Chuan-chuan Cai ),( Wei-jin Guo ),( Ying Zhou ),( Ge Shi ),( Yi-ming Fan ) 대한피부과학회 2016 Annals of Dermatology Vol.28 No.6

Background: Although Becker`s nevus (BN) is a relatively common disease, the systematic studies of clinicopathological and immunohistochemical results are poorly reported. Objective: To investigate the clinicopathological features and immunohistochemical alterations of keratinocyte proliferation, melanocyte density, smooth muscle hyperplasia and nerve fiber distribution in BN. Methods: Clinical and pathological data were collected in 60 newly-diagnosed BN cases. Immunohistochemical stain of Ki-67, Melan-A, keratin 15, smooth muscle actin and protein gene product 9.5 was performed in 21 cases. Results: The median diagnostic and onset age was 17 and 12 years, respectively. Skin lesions usually appeared on the upper trunk and upper limbs. The pathological features included the rete ridge elongation and fusion and basal hyperpigmentation. Epidermal Ki-67, Melan-A and keratin 15 expression and dermal nerve fiber length were significantly higher in lesional and perilesional skin than in normal skin (p<0.05∼0.01), while smooth muscle actin expression was upregulated only in skin lesion (p<0.05). Conclusion: Although the clinical diagnosis of BN is often straightforward, histopathology is helpful to differentiate from other pigmentary disorders. The hyperproliferation of keratinocytes, melanocytes, arrector pili muscle and dermal nerve fibers could be involved in the patho-genesis of BN. (Ann Dermatol 28(6) 697∼703, 2016)

Three homologous genes encoding functional D8-sphingolipid desaturase in Populus tomentosa

Shu-Fen Li,Zan-Min Hu,Guo-Jun Zhang,Ying-Chun Yuan,Cong-Hui Wang,Wu-Jun Gao,Chuan-Liang Deng,Long-Dou Lu 한국유전학회 2014 Genes & Genomics Vol.36 No.3

Δ8-sphingolipid desaturase is characterized by itsability to catalyze desaturation at the C8 position of the longchainbase of sphingolipids in plants. No previous studieshave been conducted on genes encoding Δ8-sphingolipiddesaturases in the woody plant Populus tomentosa. In thisstudy, three genes that encode Δ8-sphingolipid desaturasewere isolated fromP. tomentosa. Among these genes, PtD8Aand PtD8B showed high sequence similarity; whereas PtD8Cexhibited large sequence divergence.RT-PCRresults showedthat PtD8A and PtD8B were expressed in all tissues detected,whereas PtD8C was not expressed in roots. Heterologousexpression in yeast revealed that PtD8A/B/C were functionalΔ8-sphingolipid desaturases, and can catalyze the C18-phytosphingeninedesaturation to produce 8(Z)- and 8(E)-C18-phytosphingenine.However, the conversion rate and ratios ofthe two products differed. Compared with control cells,transgenic yeasts expressing PtD8A/B/C exhibited enhancedaluminum tolerance. Our findings further elucidated thebiochemical functions and evolutionary history ofΔ8-sphingolipid desaturases in plants. Candidate genes forbreeding new poplar germplasm resources with enhancedtolerance ability to aluminium were also provided.