Nonlinear Robust Adaptive Control of Electro-hydrostatic Actuators With Continuous Friction Compensation

Jiahui Liu,Jianyong Yao,Wenxiang Deng 제어·로봇·시스템학회 2024 International Journal of Control, Automation, and Vol.22 No.4

Electro-hydrostatic actuators (EHAs) have gradually been applied in the flight control systems of multielectric/all-electric aircraft due to the high power-to-volume ratio and the absence of throttling loss as well as overflow loss. However, the existence of high-order dynamics, system nonlinearities, and uncertainties significantly limits the tracking performance of EHAs. This article developed a robust adaptive controller with continuous friction compensation to improve the precise control performance of an EHA with a variable load, nonlinear friction, parametric uncertainties, and unmodeled disturbances. A nonlinear robust control law is used to attenuate various disturbances, and an adaptive law is adopted to cope with parametric uncertainties. Additionally, a continuous friction model is used to describe the friction behavior of an EHA to achieve effective friction compensation and further enhance the motion performance. Moreover, the upper bounds of the matched and mismatched uncertainties can be updated in real-time via adaptive laws, which can reduce design conservatism to some degree. The Lyapunov stability analysis reveals that asymptotic performance can be guaranteed despite the presence of unmodeled disturbances and parametric uncertainties. Furthermore, the applicability of the designed control algorithm with continuous friction compensation is demonstrated with experimental results.

A Parallel Algorithm of Multiple String Matching Based on Set-Partition in Multi-core Architecture

Jiahui Liu,Fangzhou Li,Guanglu Sun 보안공학연구지원센터 2016 International Journal of Security and Its Applicat Vol.10 No.4

With the coming of the big data era, the data processing in large scale comes out with a new challenge. However, string matching still plays an important role in the network security and information retrieval fields, because of the large size of pattern set with the overhead of memory and access memory time. Improving the string matching algorithm to adapt to the large scale tasks is desirable and meaningful. In this paper, we present and implement a parallel algorithm of multiple string matching based on multi-core platform. In addition, this work focuses on the partition of pattern set by using genetic algorithm through the internal relation of the patterns to reduce the memory overhead and execution performance. Compared with the classical ones, our experiments on both high and low hit-rate data demonstrate that the performance of algorithm enhances about on average by 20%-40% in general. Besides, the proposed algorithm reduces the memory cost on average by 4%-20%.

Identification of DNA methylation and genetic alteration simultaneously from a single blood biopsy

Chen Xiaomin,Liu Jiahui,Li Jun,Xie Yinpeng,Yu Zichen,Shen Lu,Liu Qingfeng,Wu Wei,Zhao Qiang,Lin Haoxiang,Liu Gaotong,Luo Qiuping,Yang Ling,Huang Yi,Zhao Meiru,Yi Xin,Xia Xuefeng 한국유전학회 2023 Genes & Genomics Vol.45 No.5

Background High-throughput sequencing of blood cell-free DNA (cfDNA) techniques offer an opportunity to characterize and monitor cancer rapidly in a non-invasive and real-time manner. Nonetheless, there lacks a tool within therapeutic arsenal to identify multi-omics alterations simultaneously from a single biopsy. In current times, bisulfite-based sequencing detects 5mC and 5hmC at single-base resolution is the golden standard of DNA methylation, while the degradation of DNA and biased sequencing data are the problems of this method. Objective To identify the consistency analysis of methylation and genetic variation with single library, we presented a platform detecting multi-omics data simultaneously from a single blood biopsy using bisulfite-free method of genomic methylation sequencing (GM-seq) mediated by TET enzyme. Methods We detected methylomic and genetic changes simultaneously from a single blood biopsy in NA12878 and randomly chose ten blood biopsies from colorectal cancer or lung cancer patients to validate the ability of GM-seq. Results Similar cytosine methylation level between whole genome bisulfite sequencing (WGBS) and GM-seq were identified in NA12878. Moreover, longer insert size, CpGs coverage and GC distribution were outperformed than WGBS. In addition, the comparison of the single nucleotide polymorphism (SNP), insertion-deletion (Indel) and copy number variation (CNV) in NA12878 or ctDNA from liver cancer between GM-seq and whole genome sequencing (WGS) show a good consistency, indicating that this method is feasible for detecting genetic variation in blood. Conclusion In conclusion, our work demonstrated a method for identification of the methylated modification and genetic variations simultaneously from a single blood biopsy.

DFT study of the oxidation of Hg0 by O2 on an Mn-doped buckled g-C3N4 catalyst

Liu Shuai,Xu Mengxia,Chen Yipei,Mu Xueliang,Yu Jiahui,Yang Gang,Luo Xiang,Jiang Peng,Wu Tao 한국물리학회 2022 Current Applied Physics Vol.40 No.-

Due to the water-insoluble nature of Hg0, its oxidization to Hg2+, which is water-soluble, is a viable approach for its effective removal at coal-fired plants using existing flue gas desulfurization (FGD) unit. In this study, the adsorption and oxidation of elemental mercury on an Mn-doped g-C3N4 material were investigated. The spinpolarized density functional theory method was adapted to optimize the geometry structures and then to determine the corresponding electronic structures, while the CI-NEB method was adopted to search for the stable intermediates during the reaction(s). The analysis of energy and project density of states shows that the Mn-g- C3N4 exhibits an excellent affinity to Hg atoms. It is found that it is feasible for Hg atoms to oxidize on the Mn-g- C3N4 surface via two possible E-R paths, but with relatively high energy barriers. This research provides insights into a viable way for mercury removal using O2 as the oxidizing agent.

Stochastic Disturbance Propagation Model Analysis of Power Grids Based on Epidemic Model and Improved Clustering

Jiahui Jin,Yonghui Liu 제어·로봇·시스템학회 2022 International Journal of Control, Automation, and Vol.20 No.12

Based on epidemic model, a stochastic disturbance propagation model of power grids is proposed in this paper. Firstly, compared with epidemic model, some concepts in power grids are introduced. Then, by analyzing parameters of the nodes, some key nodes are extracted. Hence, the complex power grids are divided into some simple power grids. For the simple power grids, taking Markovian chain into account, the probability of the propagation is solved backward. Combined with the probability and the parameters of the power grids, a model describing importance of the nodes is established. Finally, to demonstrate the effectiveness of the model, an improved clustering algorithm is proposed. The simulation results show that the model has high accuracy in selecting the key nodes. Moreover, it provides an effective method in prediction of power grids.

Untargeted metabolite profiling of serum in rats exposed to pyrraline

Chuanqin Hu,Jiahui Wang,Fangyuan Qi,Yingli Liu,Fen Zhao,Jing Wang,Baoguo Sun 한국식품과학회 2023 Food Science and Biotechnology Vol.32 No.11

Pyrraline, one of advanced glycation end-products, is formed in advanced Maillard reactions. It was reported that the presence of pyrraline was tested to be associated with nephropathy and diabetes. Pyrraline might result in potential health risks because many modern diets are heat processed. In the study, an integrated metabolomics by ultra-high-performance liquid chromatography with mass spectrometry was used to evaluate the effects of pyrraline on metabolism in rats. Thirty-two metabolites were identified as differential metabolites. Linolenic acid metabolism, phenylalanine, tyrosine and tryptophan biosynthesis, arachidonic acid metabolism, tyrosine metabolism and glycerophospholipid metabolism were the main perturbed networks in this pathological process. Differential metabolites and metabolic pathways we found give new insights into studying the toxic molecular mechanisms of pyrraline.

CO catalytic oxidation over graphene with double vacancy-embedded molybdenum: a DFT investigation

Dai Guoliang,Liu Jiahui,Qian Hui 한국탄소학회 2019 Carbon Letters Vol.29 No.4

Based on the M06-2X density functional, the catalytic oxidation of CO by O2 over Mo-embedded graphene was investigated in detail. The model with molybdenum atom embedded in double vacancy (DV) in a graphene sheet was considered. It is found that the complete CO oxidation reactions over Mo-DV-graphene include a two-step process, in which the first step prefers to Langmuir–Hinshelwood mechanism and followed the progress of CO oxidation with a remaining atomic Otop. Compared with the structure of Mo atom decorated at the single carbon vacancy on graphene (Mo-SV-graphene), the catalytic activity of Mo-DV-graphene is weaker. The present results imply that the catalytic activity of Mo-embedded graphene for CO oxidation can be improved by increasing the ratio of single vacancy (SV).

CO catalytic oxidation over graphene with double vacancy‑embedded molybdenum: a DFT investigation

Guoliang Dai,Jiahui Liu,Hui Qian 한국탄소학회 2019 Carbon Letters Vol.29 No.4

Based on the M06-2X density functional, the catalytic oxidation of CO by O2 over Mo-embedded graphene was investigated in detail. The model with molybdenum atom embedded in double vacancy (DV) in a graphene sheet was considered. It is found that the complete CO oxidation reactions over Mo-DV-graphene include a two-step process, in which the first step prefers to Langmuir–Hinshelwood mechanism and followed the progress of CO oxidation with a remaining atomic Otop. Compared with the structure of Mo atom decorated at the single carbon vacancy on graphene (Mo-SV-graphene), the catalytic activity of Mo-DV-graphene is weaker. The present results imply that the catalytic activity of Mo-embedded graphene for CO oxidation can be improved by increasing the ratio of single vacancy (SV).

The evolution of radiation-induced point defects near symmetrical tilt Σ5 (310) <001> grain boundary in pure δ-plutonium: A molecular dynamics study

Wang, Yangzhong,Liu, Wenbo,Zhang, Jiahui,Yun, Di,Chen, Piheng Korean Nuclear Society 2021 Nuclear Engineering and Technology Vol.53 No.5

The effects of the symmetrical tilt Σ5 (310) <001> grain boundary (GB) on the evolution of radiation-induced point defects in pure δ-plutonium (Pu) were studied by Molecular dynamics (MD) simulations. The evolution of radiation-induced point defects was obtained when primary knock-on atom (PKA) was respectively set as -15 Å and 15 Å far from the GB and the number of residual defects was obtained as the distance from PKA to GB was changed. According to the results, compared with vacancies, interstitial atoms were more easily absorbed by GB. In addition, the formation energy of point defects was also calculated. The results showed that there was almost no difference for the formation energy of vacancies in the all matrix. However, the formation energy of interstitial atoms close to the GB was lower than that in the other bulk regions.

Research Progress of the Structure Vibration-Attitude Coordinated Control of Spacecraft

Jingyu Yang,Shiying Qu,Jiahui Lin,Zhiqi Liu,Xuanming Cui,Chu Wang,Dujiang Zhang,Mingcheng gu,Zhongrui Sun,Kang Yang,Lanwei Zhou,Guoping Chen 한국항공우주학회 2015 International Journal of Aeronautical and Space Sc Vol.16 No.4

This paper gives an overview of research on the field of structure vibration-attitude coordinated control of spacecraft. First of all, the importance of the technology has been given an introduction, and then later the research progress of space structure dynamics modeling, research progress of structure vibration-attitude coordinated control of flexible spacecraft have been discussed respectively. Finally, future research on application of structure vibration-attitude coordinated control of spacecraft has been recommended.