Aperiodically Intermittent Adaptive Event-triggered Control for Linear Multi-agent Systems

Yunlong Zhang,Guoguang Wen,Ahmed Rahmani,Xiaoqin Zhai 제어·로봇·시스템학회 2023 International Journal of Control, Automation, and Vol.21 No.1

This paper investigates the aperiodically intermittent adaptive event-triggered control strategy for general linear multi-agent systems. The aperiodically intermittent adaptive event-triggered control inherits the respective advantages of aperiodically intermittent control strategy, event-triggered control strategy and adaptive control strategy, which improves communication efficiency, reduces control update frequency and is closer to the practical situations. Firstly, to reach leader-following consensus and save more control resources, a distributed aperiodically intermittent event-triggered scheme is devised, in which the transmission channels among agents only open if the local event-trigger condition is satisfied in predefined time intervals. Then, in order to get rid of continuous inter-agent communication for monitoring the triggering condition, a more general triggering mechanism is presented, in which discrete-time combinational measurement is adopted instead of using continuous-time tracking error directly. Next, to overcome the unexpected large feedback gains in real applications and appropriately tune the feedback gains, the aperiodically intermittent adaptive event-triggered controller is further devised. With aid of the matrix theory, stability theory of switching systems and Lyapunov function, some sufficient criteria are deduced. Moreover, the analyses of excluding the Zeno behavior are included, and explicit positive lower bounds between any two consecutive time intervals are rigorously guaranteed. Finally, the effectiveness for the designed control strategies is validated by simulations.

Microstructure and Hydrogen Absorption Properties of a BCC Phase Accompanied Laves Alloy

Yunlong Zhang,Tiebang Zhang,Jinshan Li,Ruolin Li,Yun Yu,Yalin Lu 대한금속·재료학회 2019 METALS AND MATERIALS International Vol.25 No.3

A non-stoichiometry Zr0.7Ti0.4V1.5Cr0.4alloy has been synthesized by arc melting following annealing treatment or meltspinningto obtain the bulk and ribbon samples, respectively. XRD investigation reveals the multiphase structure consistingof C15-Laves, V-BCC and a small amount of α-Zr or Zr3V3O. The alloy shows easy activation and fast hydrogenationkinetics. The annealed alloy absorbs 2.51 wt% H at room temperature, higher than the melt-spun ribbons. Refined grains bymelt-spinning accelerates the hydrogenation of bulk alloy. The absorption behavior in presence of 1 mol% air has been testedto evaluate the anti-poisoning ability. Pressure–composition–temperature characteristics and thermodynamics parametersindicate the low equilibrium pressure and high hydrides stability. Hydrides investigation reveals that the Laves phase dominantmultiphase structure contributes to the enhanced hydrogen capacity and multi-stage hydrogen release in DSC curve.

Pedestrian Choices of Vertical Walking Facilities inside Urban Rail Transit Stations

Ning Zhang,Yunlong Zhang,Xiaojun Zhang 대한토목학회 2015 KSCE JOURNAL OF CIVIL ENGINEERING Vol.19 No.3

This paper investigates pedestrians’ choices between escalator and stairway inside urban rail transit stations during peak hours. After the review of mode choice models, a logit model based on the utility maximization theory is selected. Binary logit models forthe passenger flow distribution are established with walking time, walking distance, gender and age of the passenger as the maininfluencing factors. The influences of these factors are quantitatively analyzed through data collected from three rail transit stationswith different arrangement forms of vertical walking facilities in Nanjing, China. The developed models are verified to produce ahigh accuracy in predicting passengers’ choices of vertical walking facilities. With developed models, sensitivity analyses forselecting escalator for upward and downward pedestrians in the three types of stations are also conducted and compared to furtherreveal the differences in pedestrians' choices of using vertical walking facilities. The modeling procedure and results can provide atheoretical reference for operation decisions, such as the planning of vertical walking facilities and passenger flow organization inbusy rail transit stations.

Microwave Sintering of Graphene-Nanoplatelet-Reinforced Al₂O₃-based Composites

Ai, Yunlong,Liu, Ying,Zhang, Qiuyu,Gong, Yuxing,He, Wen,Zhang, Jianjun The Korean Ceramic Society 2018 한국세라믹학회지 Vol.55 No.6

In this study, we performed a microwave sintering (MWS) of $Al_2O_3$ ceramic and $Al_2O_3$-based composites with nominal contents of graphene nanoplatelets (GPLs) of 0.2, 0.4, 0.6, and 0.8 vol%. The GPL dispersion in N-methyl pyrroleketone was optimized to deagglomerate the GPLs without damaging their structure. Dense composites were then obtained by MWS at $1500^{\circ}C$ for 30 min. The effects of different GPL contents on the phase compositions, microstructures, and mechanical properties of the composites were investigated. The microstructures of the composites became finer with the incorporation of the GPLs. The well-dispersed GPL fillers led to higher sintered densities in the composites. The optimal mechanical properties were achieved with 0.4 vol% GPLs. For this sample, the hardness, fracture toughness, and bending strength were $2000kgf/mm^2$, $6.19MPa{\cdot}m^{1/2}$, and 365.10 MPa, respectively. The addition of GPL could improve the microstructure of the $Al_2O_3$ ceramic and has potential to improve the fracture toughness of the ceramics.

Research on a Spectral Reconstruction Method with Noise Tolerance

Yunlong Ye,Jianqi Zhang,Delian Liu,Yixin Yang 한국광학회 2021 Current Optics and Photonics Vol.5 No.5

As a new type of spectrometer, that based on filters with different transmittance features attracts a lot of attention for its advantages such as small-size, low cost, and simple optical structure. It uses post-processing algorithms to achieve target spectrum reconstruction; therefore, the performance of the spectrometer is severely affected by noise. The influence of noise on the spectral reconstruction results is studied in this paper, and suggestions for solving the spectral reconstruction problem under noisy conditions are given. We first list different spectral reconstruction methods, and through simulations demonstrate that these methods show unsatisfactory performance under noisy conditions. Then we propose to apply the gradient projection for sparse reconstruction (GRSR) algorithm to the spectral reconstruction method. Simulation results show that the proposed method can significantly reduce the influence of noise on the spectral reconstruction process. Meanwhile, the accuracy of the spectral reconstruction results is dramatically improved. Therefore, the practicality of the filter-based spectrometer will be enhanced.

Genome-wide DNA methylation analysis in schizophrenia with tardive dyskinesia: a preliminary study

Zhang Ping,Lu Yongke,Li Yanli,Wang Kesheng,An Huimei,Tan Yunlong 한국유전학회 2023 Genes & Genomics Vol.45 No.10

Background Tardive dyskinesia (TD) develops in 20–30% of schizophrenia patients and up to 50% in patients > 50 years old. DNA methylation may play an important role in the development of TD. Objective DNA methylation analyses in schizophrenia with TD. Methods We conducted a genome-wide DNA methylation analysis in schizophrenia with TD using methylated DNA immunoprecipitation coupled with next-generation sequencing (MeDIP-Seq) in a Chinese sample including five schizophrenia patients with TD and five without TD (NTD), and five healthy controls. The results were expressed as the log2FC, fold change of normalized tags between two groups within the differentially methylated region (DMR). For validation, the pyrosequencing was used to quantify DNA methylation levels of several methylated genes in an independent sample (n = 30). Results Through genome-wide MeDIP-Seq analysis, we identified 116 genes that were significantly differentially methylated in promotor regions in comparison of TD group with NTD group including 66 hypermethylated genes (top 4 genes are GABRR1, VANGL2, ZNF534, and ZNF746) and 50 hypomethylated genes (top 4 genes are DERL3, GSTA4, KNCN, and LRRK1). Part of these genes (such as DERL3, DLGAP2, GABRR1, KLRG2, LRRK1, VANGL2, and ZP3) were previously reported to be associated with methylation in schizophrenia. Gene Ontology enrichment and KEGG pathway analyses identified several pathways. So far, we have confirmed the methylation of 3 genes (ARMC6, WDR75, and ZP3) in schizophrenia with TD using pyrosequencing. Conclusions This study identified number of methylated genes and pathways for TD and will provide potential biomarkers for TD and serve as a resource for replication in other populations.

Effects of the Inlet Position of Blade on the Performance of a Centrifugal Impeller

Yunlong Li,Ruizi Zhang,Kaibin Wang,Jingyin Li 한국유체기계학회 2018 International journal of fluid machinery and syste Vol.11 No.3

The effects of the inlet position of blade on the performance of a centrifugal impeller are numerically investigated. The inlet position of the blade can be determined by the outer diameter, the leaning angle of the blade inlet, the shroud and hub angular momentums specified at the blade inlet. It is found that the flow fields of the optimal impeller are obviously superior to those of the impeller whose blade leading edge was installed at impeller eye. The range analyses reveal that angular momentum specified at the inlet hub is the least important factor in affecting the efficiency of impeller, while the outer diameter of blade leading edge plays the most important role in determining the pressure ratio.

Distribution of pathological types and epidemiological characteristics based on kidney biopsy in Northwest China

Qin Yunlong,Zhao Jin,Wei Xiao-fei,Wang Yuwei,Yu Zixian,Zhang Yumeng,Sun Shiren 대한신장학회 2023 Kidney Research and Clinical Practice Vol.42 No.1

Background: The spectrum of biopsy-confirmed kidney disease varies with regions and periods. We describe the distribution ofpathological types and epidemiological characteristics of kidney diseases in Northwest China due to regional differences in geographicalenvironment, social economy, and dietary habits.Methods: Kidney biopsy cases from 2005 to 2020 in Xijing Hospital were retrospectively analyzed. Pathological characteristics of patientsin different periods were analyzed using the t test or chi-square test. Joinpoint regression was used to analyze trends in pathologicaltypes and disease spectrum.Results: A total of 10,528 eligible patients were included. Primary glomerular disease (PGD) accounted for the majority of the casesand exhibited an obvious downward trend, whereas secondary glomerular disease (SGD) showed an obvious upward trend. AmongPGD, immunoglobulin A nephropathy (IgAN) remained the most common pathological type, and the detection rate of membranousnephropathy (MN) was significantly increased. Among SGD, Henoch-Schönlein purpura nephritis (HSPN) was the most commonpathological type and may present a significant characteristic of Northwest China. Diabetic nephropathy (DN) exhibited the most obviousupward trend in the whole process, whereas the fastest growth since 2012 was in hypertensive nephropathy.Conclusion: The proportion of SGD increased whereas PGD declined. IgAN remained the most common PGD, and HSPN was themost common SGD. MN and DN showed the most obvious upward trend among PGD and SGD, respectively. Changes in the spectrumof kidney disease, especially the constituent ratio of SGD, pose a great challenge to public health.

Effects of the Guiding Tank on Flow Characteristics inside the Double-Suction Squirrel-Cage Fan for Range Hood

Yingkun Zhang,Kunhang Li,Yunlong Li,Jingyin Li 한국유체기계학회 2020 International journal of fluid machinery and syste Vol.13 No.1

The effects of the guiding tank on flow characteristics inside a double-suction squirrel-cage fan for the range hood were numerically investigated in this paper. Flow analysis was conducted by solving the three-dimensional steady Reynolds-averaged Navier-Stokes equations using the realizable k- turbulence model. Numerical results were validated with the experimental data for total pressure. Differences in flow characteristics between the fan model and the range hood model at the nearly maximum mass flow rate of 0.3214 kg/s were analyzed in detail. Numerical simulation results show that the incoming flow of the squirrel-cage fan will be distorted due to the guiding tank. The inlet distortion will deteriorate the aerodynamic performance of the squirrel-cage fan and cause obvious differences in the velocity field, the pressure field and the vortex structures inside the fan.

Aerodynamic Optimization of Squirrel-Cage Fan with Dual Inlet

Ruizi Zhang,Kaibin Wang,Yunlong Li,Jingyin Li 한국유체기계학회 2018 International journal of fluid machinery and syste Vol.11 No.3

In this paper, the rotor and the volute of the squirrel-cage fan with dual inlet were optimized to improve its aerodynamic performance. The blade inlet angle, blade exit angle and diameter ratio of the impeller were chosen as optimization variables using the response surface methodology (RSM) to improve the total pressure. Furthermore, another three optimization variables were adopted on the basis of previous optimum results, which are the width of impeller, the location of the impeller annular plate and the location of cutoff respectively. The simulation and experimental results show that the total pressure of the optimal model has been greatly improved without noise increase in comparison with the original model.