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Recorded recurrent deep reinforcement learning guidance laws for intercepting endoatmospheric maneuvering missiles

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Defence Technology（防务技术） 2024年第1期31卷 457-470页

作者： Xiaoqi Qiu peng lai Changsheng Gao Wuxing Jing Department of Aerospace Engineering Harbin Institute of TechnologyHarbin150001China Shanghai Electro-Mechanical Engineering Institute Shanghai Academy of Spaceflight TechnologyShanghai201100China

This work proposes a recorded recurrent twin delayed deep deterministic(RRTD3)policy gradient algorithm to solve the challenge of constructing guidance laws for intercepting endoatmospheric maneuvering missiles with uncertainties and observation *** attack-defense engagement scenario is modeled as a partially observable Markov decision process(POMDP).Given the benefits of recurrent neural networks(RNNs)in processing sequence information,an RNN layer is incorporated into the agent’s policy network to alleviate the bottleneck of traditional deep reinforcement learning methods while dealing with *** measurements from the interceptor’s seeker during each guidance cycle are combined into one sequence as the input to the policy network since the detection frequency of an interceptor is usually higher than its guidance *** training,the hidden states of the RNN layer in the policy network are recorded to overcome the partially observable problem that this RNN layer causes inside the *** training curves show that the proposed RRTD3 successfully enhances data efficiency,training speed,and training *** test results confirm the advantages of the RRTD3-based guidance laws over some conventional guidance laws.

关键词： Endoatmospheric interception Missile guidance Reinforcement learning Markov decision process Recurrent neural networks

Variable Selection for Fixed Effects Varying Coefficient Models

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Acta Mathematica Sinica,English Series 2015年第1期31卷 91-110页

作者： Gao Rong LI Heng LIAN peng lai Heng peng Beijing Center for Scientific and Engineering Computing College of Applied SciencesBeijing University of Technology School of Mathematics and Statistics The University of New South Wales School of Mathematics & Statistics Nanjing University of Information Science & Technology Department of Mathematics Hong Kong Baptist University

We consider the problem of variable selection for the fixed effects varying coefficient models. A variable selection procedure is developed using basis function approximations and group nonconcave penalized functions, and the fixed effects are removed using the proper weight matrices. The proposed procedure simultaneously removes the fixed individual effects, selects the significant variables and estimates the nonzero coefficient functions. With appropriate selection of the tuning parameters, an asymptotic theory for the resulting estimates is established under suitable conditions. Simulation studies are carried out to assess the performance of our proposed method, and a real data set is analyzed for further illustration.

关键词： Varying coefficient model fixed effect variable selection basis function

Functionalization of covalent organic frameworks via multicomponent reactions

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Science China Chemistry 2024年第12期67卷 3906-3914页

作者： Xue-Hui Liu peng-lai Wang Wei Wang San-Yuan Ding State Key Laboratory of Applied Organic Chemistry College of Chemistry and Chemical EngineeringMOE Frontiers Science Center for Rare IsotopesLanzhou UniversityLanzhou 730000China

Functionalized covalent organic frameworks(COFs)represent a fascinating class of porous materials that have attracted widespread interest due to their modifiable structures and impressive potential ***,the construction of functionalized COFs remains difficult as it requires simultaneous consideration of robust linkages,diversified structures,and tailorable ***,the introduction of multicomponent reactions(MCRs)into COF synthesis opens new avenues for creating highly stable and function-oriented COF materials,marking a significant advance in the development of *** minireview summarizes the types of MCRs used in COF synthesis,highlights the functionalization strategies of COFs via MCRs,and provides insights on the key challenges and future frontiers in this field.

关键词： covalent organic frameworks multicomponent reactions functionalization strategies

Characterization of the generalized permeability jail in tight reservoirs by analyzing relative-permeability curves and numerical simulation

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Petroleum Science 2023年第5期20卷 2939-2950页

作者： Feng-peng lai Zhi-Ping Li He-Xin Wei Wei Zhang School of Energy Resources China University of GeosciencesBeijing100083China Beijing Key Laboratory of Unconventional Natural Gas Geological Evaluation and Development Engineering Beijing100083China Changchun Oil Production Plant of Jilin Oilfield PetroChinaChangchun130062JilinChina Changqing Oilfield Company PetroChinaXi'an710018ShaanxiChina

This study comprehensively characterizes the boundary values of generalized permeability jail in tight reservoirs through relative-permeability curve analysis,numerical simulation,and economic evaluation.A total number of 108 relative-permeability curves of rock samples from tight reservoirs were obtained,and the characteristics of relative-permeability curves were *** irreducible water saturation(Swi)mainly ranges from 20% to 70%,and the residual gas saturation(Sgr)ranges from 5% to 15% for 55% of the *** relative-permeability curves are categorized into six types(Category-Ⅰ to Ⅵ)by analyzing the following characteristics:The relative permeability of gas at Swi,the relative permeability of water at Sgr,and the relative permeability corresponding to the isotonic *** relative permeability curves were normalized to facilitate numerical simulation and evaluate the impact of different types of curves on production *** results of simulation show significant difference in production performance for different types of relative-permeability curves:Category-Ⅰ corresponds to the case with best well performance,whereas Categories-Ⅴ and Ⅵ correspond to the cases with least production *** results of economic evaluation show a generalized permeability jail for Categories-Ⅳ,Ⅴ,and Ⅵ,and the permeability jail develops when the relative permeability of gas and water is below *** study further quantifies the range of micro-pore parameters corresponding to the generalized permeability jail for a tight sandstone reservoir.

关键词： Generalized permeability jail Characterization Relative permeability curve Numerical simulation Pore structure

Mechanism underlying treatment of ischemic stroke using acupuncture:transmission and regulation

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Neural Regeneration Research 2021年第5期16卷 944-954页

作者： Bing-Qian Cao Feng Tan Jie Zhan peng-Hui lai Department of Neurology Foshan Hospital of Traditional Chinese MedicineGuangzhou University of Chinese MedicineFoshanGuangdong ProvinceChina Department of Rehabilitation Guangdong Provincial Hospital of Chinese MedicineGuangzhouGuangdong ProvinceChina Department of Rehabilitation Nan’ao People’s Hospital Dapeng New DistrictShenzhenGuangdong ProvinceChina

The inflammatory response after cerebral ischemia/reperfusion is an important cause of neurological damage and *** cerebral ischemia/reperfusion,microglia are activated,and a large number of circulating inflammatory cells infiltrate the affected *** leads to the secretion of inflammatory mediators and an inflammatory cascade that eventually causes secondary brain damage,including neuron necrosis,blood-brain barrier destruction,cerebral edema,and an oxidative stress *** of inflammatory signaling pathways plays a key role in the pathological process of ischemic *** evidence suggests that acupuncture can reduce the inflammatory response after cerebral ischemia/reperfusion and promote repair of the injured nervous *** can not only inhibit the activation and infiltration of inflammatory cells,but can also regulate the expression of inflammation-related cytokines,balance the effects of pro-inflammatory and anti-inflammatory factors,and interfere with inflammatory signaling ***,it is important to study the transmission and regulatory mechanism of inflammatory signaling pathways after acupuncture treatment for cerebral ischemia/reperfusion injury to provide a theoretical basis for clinical treatment of this type of injury using *** review summarizes the overall conditions of inflammatory cells,mediators,and pathways after cerebral ischemia/reperfusion,and discusses the possible synergistic intervention of acupuncture in the inflammatory signaling pathway network to provide a foundation to explore the multiple molecular mechanisms by which acupuncture promotes nerve function restoration.

关键词： acupuncture central nervous system factor inflammation ischemic stroke pathways protein stroke

Role of farnesoid X receptor in establishment of ontogeny of phase-I drug metabolizing enzyme genes in mouse liver

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Acta Pharmaceutica Sinica B 2016年第5期6卷 453-459页

作者： lai peng Stephanie Piekos Grace L.Guo Xiao-bo Zhong Department of Pharmaceutical Sciences School of PharmacyUniversity of Connecticut Key Laboratory of System Biomedicine Center for Comparative BiomedicineInstitute of Systems BiomedicineShanghai Jiao Tong University Department of Pharmacology and Toxicology School of PharmacyRutgers University

The expression of phase-I drug metabolizing enzymes in liver changes dramatically during postnatal liver *** X receptor(FXR) is critical for bile acid and lipid homeostasis in ***,the role of FXR in regulating ontogeny of phase-I drug metabolizing genes is not ***,we applied RNA-sequencing to quantify the developmental expression of phase-I genes in both Fxr-null and control(C57BL/6) mouse livers during *** samples of male C57BL/6 and Fxr-null mice at6 different ages from prenatal to adult were *** Fxr-null showed an overall effect to diminish the "day-1 surge" of phase-I gene expression,including cytochrome P450 s at neonatal *** the 185 phase-I genes from 12 different families,136 were expressed,and differential expression during development occurred in genes from all 12 phase-I families,including hydrolysis: carboxylesterase(Ces),paraoxonase(Pon),and epoxide hydrolase(Ephx); reduction: aldoketo reductase(Akr),quinone oxidoreductase(Nqo),and dihydropyrimidine dehydrogenase(Dpyd); and oxidation: alcohol dehydrogenase(Adh),aldehyde dehydrogenase(Aldh),flavin monooxygenases(Fmo),molybdenum hydroxylase(Aox and Xdh),cytochrome P450(P450),and cytochrome P450 oxidoreductase(Por).The data also suggested new phase-I genes potentially targeted by *** results revealed an important role of FXR in regulation of ontogeny of phase-I genes.

关键词： Drug metabolizing enzymes Farnesoid X receptor Liver Ontogeny Fxr-null mouse Gene expression

Safe navigation of quadrotors with jerk limited trajectory

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Frontiers of Information Technology & Electronic Engineering 2019年第1期20卷 107-119页

作者： Shu-peng lai Meng-lu LAN Ya-xuan LI Ben M.CHEN Department of Electrical and Computer Engineering National University of Singapore Graduate School for Integrative Science & Engineering National University of Singapore School of Control Science and Engineering Shandong University Department of Mechanical and Automation Engineering Chinese University of Hong Kong

Many aerial applications require unmanned aerial systems operate in safe zones because of the presence of obstacles or security regulations. It is a non-trivial task to generate a smooth trajectory satisfying both dynamic constraints and motion limits of the unmanned vehicles while being inside the safe zones. Then the task becomes even more challenging for real-time applications, for which computational efficiency is crucial. In this study, we present a safe flying corridor navigation method, which combines jerk limited trajectories with an efficient testing method to update the position setpoints in real time. Trajectories are generated online and incrementally with a cycle time smaller than 10 μs, which is exceptionally suitable for vehicles with limited onboard computational capability. Safe zones are represented with multiple interconnected bounding boxes which can be arbitrarily *** jerk limited trajectory generation algorithm has been extended to cover the cases with asymmetrical motion limits. The proposed method has been successfully tested and verified in flight simulations and actual experiments.

关键词： Quadrotor Unmanned aerial vehicle Motion planning

Glycogen synthase kinase-3β inhibitor SB216763 promotes DNA repair in ischemic retinal neurons

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Neural Regeneration Research 2021年第2期16卷 394-400页

作者： Zhang, Jing Zhi-peng, lai Chen, Pei Yang, Ying Zhuang, Jing Ke-Ming, Yu State Key Laboratory of Ophthalmology Zhongshan Ophthalmic Center Sun Yat-sen University Guangzhou Guangdong Province

Glycogen synthase kinase-3β(GSK-3β) has been shown to attenuate DNA damage in nerve cells, thereby enhancing neuronal survival under pathological conditions;however, the underlying mechanism remains unclear. An in vitro serum-starvation retinal neuron model and in vivo ischemia/reperfusion retina injury rat model were established and treated with SB216763, a GSK-3β inhibitor. SB21673 decreased the formation of γ-H2 A histone family member X foci and enhanced the viability of ischemic retinal neurons. In addition, SB216763 upregulated expression of phosphorylated-CREB1, a ligase IV transcription factor, and significantly increased the transcriptional activity of ligase IV in ischemic retinal neurons. These results were confirmed in rat retinas following ischemia/reperfusion injury. Furthermore, we found that unlike lithium chlorine(a well-known direct inhibitor of GSK-3β), SB216763 inhibited GSK-3β activity by suppressing its phosphorylation. Taken together, our results suggest that GSK-3β inhibition enhances repair of DNA double-strand breaks by upregulating ligase IV expression in ischemic retinal neurons. This study was approved by the Institutional Animal Care and Use Committee of Zhongshan Ophthalmic Center on February 18, 2018.

关键词： factor GSK-3β in vitro injury ligase IV neuroprotection optic nerve pathways protein repair

Control of the ultrafast photo-electronic dynamics of a chemical-vapor-deposited-grown graphene by ozone oxidation

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Photonics Research 2020年第1期8卷 17-23页

作者： MIN GUO lai-peng MA WENCAI REN TIANSHU lai School of Physics State Key Laboratory of Optoelectronic Materials and TechnologiesSun Yat-sen UniversityGuangzhou 510275China Shenyang National Laboratory for Material Science Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China

Diverse ultrafast dynamics have been reported on different graphene prepared by different ***-deposited(CVD)growth is regarded as a very promising method for highly efficient production of ***,CVD-grown graphene usually presents only one of the diverse ultrafast ***,control of the ultrafast photo-electronic dynamics of CVD-grown graphene is vital to present diversity for different photodetection applications of CVD-grown *** this paper,we report on the first realization to our knowledge of control of the ultrafast dynamics of CVD-grown graphene and the manifestation of diverse ultrafast dynamics on sole CVD-grown *** study the ultrafast photoelectronic dynamics of CVD-grown graphene with different degrees of oxidation caused by ozone oxidation using femtosecond time-resolved transient differential transmission spectroscopy,and we find that the ultrafast dynamics can evolve obviously with the time of ozone *** diverse ultrafast dynamics reported previously on different monolayer graphenes prepared by different methods are achieved on the sole CVD-grown graphene by controlling oxidation *** mechanism for manipulation of the ultrafast dynamics by ozone oxidation is revealed by Raman spectroscopy as the control of the Fermi level of CVD-grown *** of dynamics based on the optical conductivity model of graphene and Fermi level change well reproduce the observed diverse ultrafast *** results are very important for the diverse applications of graphene and open a new path toward the diverse ultrafast dynamics on sole graphene prepared by any method.

关键词： ozone dynamics electronic