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Random gradient-free method for online distributed optimization with strongly pseudoconvex cost functions

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Control Theory and Technology 2024年第1期22卷 14-24页

作者： xiaoxi Yan Cheng Li Kaihong Lu Hang Xu School of Electrical and Information Engineering Jiangsu UniversityZhenjiang212013JiangsuChina College of Electrical Engineering and Automation Shandong University of Science and TechnologyQingdao266590ShandongChina

This paper focuses on the online distributed optimization problem based on multi-agent systems. In this problem, each agent can only access its own cost function and a convex set, and can only exchange local state information with its current neighbors through a time-varying digraph. In addition, the agents do not have access to the information about the current cost functions until decisions are made. Different from most existing works on online distributed optimization, here we consider the case where the cost functions are strongly pseudoconvex and real gradients of the cost functions are not available. To handle this problem, a random gradient-free online distributed algorithm involving the multi-point gradient estimator is proposed. Of particular interest is that under the proposed algorithm, each agent only uses the estimation information of gradients instead of the real gradient information to make decisions. The dynamic regret is employed to measure the proposed algorithm. We prove that if the cumulative deviation of the minimizer sequence grows within a certain rate, then the expectation of dynamic regret increases sublinearly. Finally, a simulation example is given to corroborate the validity of our results.

关键词： Multi-agent system Online distributed optimization Pseudoconvex optimization Random gradient-free method

Study of Pyrolysis Characteristics and Kinetic Analysis of Shenmu Coal at a High Heating Rate Using TG-FTIR

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China Petroleum Processing & Petrochemical Technology 2024年第1期26卷 47-55页

作者： An xiaoxi Zhang Yanpeng Shang Yanchao Tian Yuanyu Qiao Yingyun Shandong University of Science and Technology Qingdao 266510ShandongChina China University of Petroleum(Huadong) Qingdao 266555ShandongChina

Coal pyrolysis is a fundamental reaction in the thermal processing and utilization of *** the behavior and kinetics of coal pyrolysis is crucial for optimizing,designing,and developing a composite riser for the staged pyrolysis gasification process of pulverized *** this study,the non-isothermal pyrolysis behavior and kinetics of coal were examined at different heating rates(30,50,100,300,500,700,and 900℃/min)using thermogravimetry(TG)coupled with Fourier-transform infrared *** of the TG/derivative TG(TG/DTG)curves indicated that coal pyrolysis mainly occurred between 300℃ and 700℃.Higher heating rates led to more volatiles being released from the coal,and a higher temperature was required to achieve rapid *** analysis showed that both the model-free methods(Friedman,Flynn-Wall-Ozawa,and Kissinger-Akahira-Sunose)and the model-based method(Coats-Redfern)effectively describe the coal pyrolysis *** change in the Ea values between the two kinetic models was consistent throughout the pyrolysis process,and the most probable mechanism was the F2 model(secondary chemical reaction).In addition,the heating rate did not change the overall reaction order of the pyrolysis process;however,a higher heating rate resulted in a decrease in the Ea value during the initial pyrolysis stage.

关键词： coal pyrolysis TG-FTIR characteristic parameters dynamics

Zeroth-Order Methods for Online Distributed Optimization with Strongly Pseudoconvex Cost Functions

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Journal of Systems Science and Information 2024年第1期12卷 145-160页

作者： xiaoxi YAN Muyuan MA Kaihong LU School of Electrical and Information Engineering Jiangsu UniversityZhenjiang 212013China School of Electrical Engineering and Automation Shandong University of Science and TechnologyQingdao 266590China

This paper studies an online distributed optimization problem over multi-agent *** this problem,the goal of agents is to cooperatively minimize the sum of locally dynamic cost *** from most existing works on distributed optimization,here we consider the case where the cost function is strongly pseudoconvex and real gradients of objective functions are not *** handle this problem,an online zeroth-order stochastic optimization algorithm involving the single-point gradient estimator is *** the algorithm,each agent only has access to the information associated with its own cost function and the estimate of the gradient,and exchange local state information with its immediate neighbors via a time-varying *** performance of the algorithm is measured by the expectation of dynamic *** mild assumptions on graphs,we prove that if the cumulative deviation of minimizer sequence grows within a certain rate,then the expectation of dynamic regret grows ***,a simulation example is given to illustrate the validity of our results.

关键词： multi-agent systems strongly pseudoconvex function single-point gradient estimator online distributed optimization

A new era for paclitaxel biosynthesis is coming

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Molecular Plant 2024年第3期17卷 370-371页

作者： Xiaonan Liu xiaoxi Zhu Jian Cheng Huifeng Jiang Key Laboratory of Engineering Biology for Low-carbon Manufacturing Tianjin Institute of Industrial BiotechnologyChinese Academy of SciencesTianjin 300308China National Center of Technology Innovation for Synthetic Biology Tianjin 300308China

Paclitaxel(Taxol)stands out as a tetracyclic diterpenoid natural product derived from the endangered plant *** as a pivotal broad-spectrum anticancer drug,it has garnered widespread attention due to its low yield,intricate structure,unique anticancer mechanism,and remarkable efficacy(Tong et al.,2021).Although chemists achieved the total synthesis of paclitaxel 30 years ago,after decades of research,the natural biosynthetic pathway for its production remains an enigma(Ajikumar et al.,2010;Malci et al.,2023).A recent breakthrough,published in Molecular Plant by Alisdair ***'s team,unveils a minimal gene set of 18 genes required for paclitaxel biosynthesis(Zhang et al.,2023),representing a significant mark toward unraveling the entire biosynthetic pathway and enhancing paclitaxel production efficiency.

关键词： breakthrough representing synthesis

Neural and Behavioral Measures of Stress-induced Impairment in Error Awareness and Post-error Adjustment

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Neuroscience Bulletin 2024年第7期40卷 937-951页

作者： Na Hu Quanshan Long xiaoxi Wang Quan Li Qing Li Antao Chen School of Preschool and Special Education Kunming UniversityKunming 650214China Faculty of Education Yunnan Normal UniversityKunming 650214China College of Teacher Education Qujing Normal UniversityQujing 655099China Key Laboratory of Cognition and Personality of Ministry of Education Faculty of PsychologySouthwest UniversityChongqing 400715China School of Psychology Shanghai University of SportShanghai 200438China

Exposure to stress negatively affects error processing,but the impact of stress on error awareness remains to be *** the present study,we examined the temporal dynamics of error awareness and post-error adjustment following acute ***-nine healthy men were randomly assigned to the control(n=26)or stress group(n=23).After stress induction,participants completed the error awareness task,and their brain activity was assessed by *** to the control group,the stress group demonstrated lower error awareness accuracy and smaller Pe(error positivity)andΔPe amplitudes following aware error responses,which indicated impairment of error awareness following ***,the stress group had lower accuracy in post-aware error responses than in post-unaware error responses and the control group,which indicated poor post-error adjustment following *** results showed a stress effect on sequential stages of error *** induces impaired error identification,which further generates maladaptive post-error performance.

关键词： Acute stress Error awareness Post-error adjustment Error positivity

Accelerated design of high-performance Mg-Mn-based magnesium alloys based on novel bayesian optimization

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Journal of Magnesium and Alloys 2024年第2期12卷 750-766页

作者： xiaoxi Mi Lili Dai Xuerui Jing Jia She Bjørn Holmedal Aitao Tang Fusheng Pan College of Materials Science and Engineering Chongqing UniversityChongqing 400044China Southwest Technology and Engineering Research Institute Chongqing 400039China National Engineering Research Center for Magnesium Alloys Chongqing UniversityChongqing 400044China Department of Materials Science and Engineering Norwegian University of Science and Technology(NTNU)Trondheim 7051Norway

Magnesium(Mg),being the lightest structural metal,holds immense potential for widespread applications in various *** development of high-performance and cost-effective Mg alloys is crucial to further advancing their commercial *** the rapid advancement of machine learning(ML)technology in recent years,the“data-driven''approach for alloy design has provided new perspectives and opportunities for enhancing the performance of Mg *** paper introduces a novel regression-based Bayesian optimization active learning model(RBOALM)for the development of high-performance Mg-Mn-based wrought *** employs active learning to automatically explore optimal alloy compositions and process parameters within predefined ranges,facilitating the discovery of superior alloy *** model further integrates pre-established regression models as surrogate functions in Bayesian optimization,significantly enhancing the precision of the design *** RBOALM,several new high-performance alloys have been successfully designed and ***,after mechanical property testing of the designed alloys,the Mg-2.1Zn-2.0Mn-0.5Sn-0.1Ca alloy demonstrates exceptional mechanical properties,including an ultimate tensile strength of 406 MPa,a yield strength of 287 MPa,and a 23%fracture ***,the Mg-2.7Mn-0.5Al-0.1Ca alloy exhibits an ultimate tensile strength of 211 MPa,coupled with a remarkable 41%fracture elongation.

关键词： Mg-Mn-based alloys High-performance Alloy design Machine learning Bayesian optimization

Urchin-like Na-doped zinc oxide nanoneedles for low-concentration and exclusive VOC detections

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Journal of Advanced Ceramics 2024年第4期13卷 507-517页

作者： Yiwen Zhou Yifan Luo Zichen Zheng Kewei Liu xiaoxi He Kaidi Wu Marc Debliquy Chao Zhang College of Mechanical Engineering Yangzhou UniversityYangzhou 225127China Material Science Department University of MonsMons 7000Belgium

In the early-stage diagnosis of lung cancer,the low-concentration(<5 ppm)volatile organic compounds(VOCs)are extensively identified to be the biomarkers for breath ***,the urchin-like sodium(Na)-doped zinc oxide(ZnO)n... 详细信息

In the early-stage diagnosis of lung cancer,the low-concentration(21.3@5 ppm)compared with pristine ZnO(~7-fold),low limit of detection(LOD)(298 ppb),robust humidity resistance,and long-term stability of formaldehyde sensing performances were obtained,which can be attributed to the formation of a higher concentration of oxygen vacancies(20.98%)and the active electron ***,the improved sensing mechanism was demonstrated by the exquisite band structure and introduction of the additional acceptor level,which resulted in the narrowed bandgap of ZnO.

关键词： zinc oxide(ZnO) heterovalent ions doping citric acid gas sensor volatile organic compound(VOC)detection lungcancer

Perfluorinated iodine alkanes promote the differentiation of mouse embryonic stem cells by regulating estrogen receptor signaling

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Journal of Environmental Sciences 2024年第3期137卷 443-454页

作者： Zhihua Ren xiaoxi Yang Tingting Ku Qian S.Liu Jiefeng Liang Qunfang Zhou Francesco Faiola Guibin Jiang State Key Laboratory of Environmental Chemistry and Ecotoxicology Research Center for Eco-Environmental SciencesChinese Academy of SciencesBeijing 100085China College of Resources and Environment University of Chinese Academy of SciencesBeijing 100049China College of Environment and Resource Research Center of Environment and HealthShanxi UniversityTaiyuan 030006China College of Sino-Danish University of Chinese Academy of SciencesBeijing 100049China

Investigating the development toxicity of perfuorinated iodine alkanes(PFIs)is critical,given their estrogenic effects through binding with estrogen receptors(ERs).In the present study,two PFIs,including dodecafuoro-1,6-diiodohexane(PFHx DI)and tridecafuorohexyl iodide(PFHx I),with binding preference to ERαand ERβ,respectively,were selected to evaluate their effects on proliferation and differentiation of the mouse embryonic stem cells(m ESCs).The results revealed that,similar to E_(2),50μmol/L PFHx DI accelerated the cell proliferation of the m *** PFI stimulation at the exposure concentrations of 2–50μmol/L promoted the differentiation of the m ESCs as characterized by the upregulation of differentiation-related biomarkers(i.e.,Otx2 and Dnmt3β)and downregulation of pluripotency genes(i.e.,Oct4,Nanog,Sox2,Prdm14 and Rex1).Comparatively,PFHx DI exhibited higher induction effect on the differentiation of the m ESCs than did PFHx *** tests on ER signaling indicated that both PFI compounds induced exposure concentration-dependent expressions of ER signaling-related biomarkers(i.e.,ERα,ERβand Caveolin-1)in the m ESCs,and the downstream ER responsive genes(i.e.,c-fos,c-myc and c-jun)well responded to PFHx I *** role of ER in PFI-induced effects on the m ESCs was further validated by the antagonistic experiments using an ER inhibitor(ICI).The findings demonstrated that PFIs triggered ER signaling,and perturbed the differentiation program of the m ESCs,causing the potential health risk during early stage of development.

关键词： Perfuorinated iodine alkanes(PFIs) Embryonic stem cells(ESCs) Developmental toxicity Cell differentiation Estrogen receptor-related signaling

A growth-regulating factor 7(GRF7)-mediated gene regulatory network promotes leaf growth and expansion in sugarcane

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The Crop Journal 2024年第2期12卷 422-431页

作者： Qiaoyu Wang Yihan Li Dadong Lin xiaoxi Feng Yongjun Wang Tianyou Wang Hongyan Ding Jisen Zhang State Key Lab for Conservation and Utilization of Subtropical AgroBiological Resources and Guangxi Key Lab for Saccharum Biology Guangxi UniversityNanning 530005GuangxiChina Center for Genomics and Biotechnology/Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology/Key Laboratory of Saccharum Biology and Genetic Breeding/National Engineering Research Center for Saccharum Fujian Agriculture and Forestry UniversityFuzhou 350002FujianChina

Knowledge of the function of growth-regulating factors(GRFs)in sugarcane(Saccharum officinarum and ***)growth and development could assist breeders in selecting desirable plant ***,limited information about GRFs is available in Saccharum due to their *** this study,22 GRFs were identified in the two species and their conserved domains,gene structures,chromosome location,and synteny were ***7 expression varied among tissues and responded to diurnal ***7-YFP was localized preferentially in the nucleus and appears to act as a transcriptional ***7 positively regulated the size and length of rice leaves,possibly by regulating cell size and plant *** seven potential transcription factors binding to the SsGRF7 promoter in ***,four showed positive expression patterns,and two showed negative expression patterns relative to SsGRF7.

关键词： Expression analysis Growth-regulating factor Leaf development Sugarcane Transcription factors