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Proportional Mean Residual Life Model with Varying Coefficients for Length-Biased and Right-Censored Data

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Acta Mathematica Sinica,English Series 2020年第5期36卷 578-596页

作者： Da XU Yong Zhou Key Laboratory of Applied Statistics of MOE and School of Mathematics and Statistics Northeast Normal UniversityChangchun 130024P.R.China Key Laboratory of Advanced Theory and Application in Statistics and Data Science MOEAcademy of Statistics and Interdisciplinary SciencesEast China Normal UniversityShanghai 200062P.R.China Academy of Mathematics and Systems Sciences Chinese Academy of SciencesBeijing 100190P.R.China

Length-biased data are encountered in many fields,including economics,engineering and epidemiological cohort studies.There are two main challenges in the analysis of such data:the assumption of independent censoring is violated and the assumed model for the underlying population is no longer satisfied for the observed data.In this paper,a proportional mean residual life varyingcoefficient model for length-biased data is considered and a local pseudo likelihood method is proposed for estimating the coefficient functions in the model.Asymptotic properties are investigated for the proposed estimators.The finite sample performance of the proposed methodology is demonstrated by simulation studies.Finally,the method is applied to a real data set concerning the Academy Awards.

关键词： Length-biased data proportional hazards model mean residual life varying-coefficient model

Cortical Mechanisms of Multisensory Linear Self-motion Perception

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Neuroscience Bulletin 2023年第1期39卷 125-137页

作者： Luxin zhou yong Gu CAS Center for Excellence in Brain Science and Intelligence Technology Institute of NeuroscienceChinese Academy of SciencesShanghai200031China University of Chinese Academy of Sciences Beijing100049China

Accurate self-motion perception,which is critical for organisms to survive,is a process involving multiple sensory cues.The two most powerful cues are visual(optic flow)and vestibular(inertial motion).Psychophysical studies have indicated that humans and nonhuman primates integrate the two cues to improve the estimation of self-motion direction,often in a statistically Bayesian-optimal way.In the last decade,single-unit recordings in awake,behaving animals have provided valuable neurophysiological data with a high spatial and temporal resolution,giving insight into possible neural mechanisms underlying multisensory self-motion perception.Here,we review these findings,along with new evidence from the most recent studies focusing on the temporal dynamics of signals in different modalities.We show that,in light of new data,conventional thoughts about the cortical mechanisms underlying visuo-vestibular integration for linear self-motion are challenged.We propose that different temporal component signals may mediate different functions,a possibility that requires future studies.

关键词： Multisensory integration Self-motion perception Vestibular Optic flow

State-of-the-art advancements of transition metal oxides as photoelectrode materials for solar water splitting

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Rare Metals 2022年第7期41卷 2370-2386页

作者： Gai-Li Ke Bi Jia Hui-Chao He Yong Zhou Ming zhou State Key Laboratory of Environmental-Friendly Energy Materials School of Materials Science and EngineeringSouthwest University of Science and TechnologyMianyang 621010China Institute of Environmental Energy Materials and Intelligent Devices School of Metallurgy and Materials EngineeringChongqing University of Science and TechnologyChongqing 401331China Ecomaterials and Renewable Energy Research Center School of PhysicsNanjing UniversityNanjing 211102China Department of Chemistry State University of New YorkBinghamton NY 13902USA

Photoelectrochemical(PEC)water splitting can convert renewable solar energy into clean hydrogen fuel.Photoelectrodes are the core components of water-splitting cells.In the past 40 years,a series of binary and ternary transition metal oxides have been investigated as photo-electrode materials for solar water splitting,and numerous studies have been carried out to modify their water-split-ting performances.Although satisfactory transition metal oxide photoelectrode materials have not been found,it is necessary to summarize the recent advancements in tran-sition metal oxide photoelectrode materials to guide future research.In this review,the background and principle of PEC water splitting are introduced.The semiconductor properties and modification progress of typical binary and ternary metal oxide photoanodes and photocathodes for solar water splitting are summarized.Based on the newly developed strategies in recent years,a brief outlook is presented for efficient PEC water splitting using transition metal oxide photoelectrodes.

关键词： Transition metal oxides Photoanodes Photocathodes Water splitting Review

RIS-Assisted Over-the-Air Federated Learning in Millimeter Wave MIMO Networks

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Journal of Communications and Information Networks 2022年第2期7卷 145-156页

作者： Lin Hu Zhibin Wang Hongbin Zhu Yong Zhou School of Information Science and Technology ShanghaiTech UniversityShanghai 201210China Shanghai Institute of Microsystem and Information Technology Chinese Academy of SciencesShanghai 200050China

In this paper,we propose a reconfigurable intelligent surface(RIS)assisted over-the-air federated learning(FL),where multiple antennas are deployed at each edge device to enable simultaneous multidimensional model transmission over a millimeter wave(mmWave)network.We conduct rigorous convergence analysis for the proposed FL system,taking into account dynamic channel fading and analog transmissions.Inspired by the convergence analysis,we propose to jointly optimize the receive digital and analog beamforming matrices at the access point,the RIS phase-shift matrix,as well as the transmit beamforming matrices at transmitting devices to minimize the transmission distortion.The optimization variable coupling and non-convex constraints make the formulated problem challenging to be solved.To this end,we develop a low-complexity Riemannian conjugate gradient(RCG)-based algorithm to solve the unit modulus constraints and decouple the optimization variables.Simulations show that the proposed RCG algorithm outperforms the successive convex approximation algorithm in terms of the learning performance.

关键词： reconfigurable intelligent surface federated learning Riemannian conjugate gradient over-the-air computation

First report of complete mitochondrial genome in the subfamily Alleculinae and mitochondrial genome-based phylogenetics in Tenebrionidae(Coleoptera:Tenebrionoidea)

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Insect Science 2022年第4期29卷 1226-1238页

作者： Chuan Wu Yong Zhou Tian Tian Ting-Jing Li Bin Chen Chongqing Key Laboratory of Vector Insects Institute of Entomology and Molecular BiologyChongqing Normal UniversityChongqingChina

Despite worldwide distribution and rich diversity,the knowledge of mitochondrial genome(mtgenome)characteristics within the family Tenebrionidae(Coleoptera)is still very limited,and phylogenetics remain unresolved for the family.In this study,the mtgenomes for 12 species are newly sequenced and annotated.Three of the species represent the first report of complete mtgenomes from the subfamily Alleculinae.Comparative analysis of 36 tenebrionid mtgenomes finds that gene composition and order are the same as a theoretical ancestral insect mtgenome,and AT bias,length variation,and codon usage are consistent with other reported beetle mtgenomes.Some intergenic overlap and gap sequences may contain phylogenetically informative information,whereas neither the conserved nor repeat sequences in the control region do.The subfamilies Lagriinae,Pimeliinae,Stenochiinae,and Alleculinae are found to be monophyletic,and the subfamilies Diaperinae and Tenebrioninae polyphyletic in our study.Furthermore,Lagriinae is sister to the rest of the subfamilies.At the tribal level,the tribes Lagriini in the subfamily Lagrrinae;Strongyliini in Stenochiinae;Cteniopodini in Alleculinae;and Triboliini,Opatrini,and Amarygmini in Tenebrioninae are monophyletic;while Diaperini in Diaperinae,and Tenebrionini in Tenebrioninae are polyphyletic.

关键词： Alleculinac characteristics Colcopiera mtgenome phylogenetics Tenebrionidac

A novel nonparametric mixture model for the detection pattern of COVID-19 on Diamond Princess cruise

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Statistical Theory and Related Fields 2023年第1期7卷 85-96页

作者： Huijuan Ma Jing Qin Fang Chen Yong Zhou KLATASDS-MOE School of Statistics and Academy of Statistics and Interdisciplinary SciencesEast China Normal UniversityShanghaiPeople’s Republic of China National Institute of Allergy and Infectious Diseases National Institutes of HealthBethesdaMDUSA School of Statistics and Management Shanghai University of Finance and EconomicsShanghaiPeople’s Republic of China

The outbreak of COVID-19 on the Diamond Princess cruise ship has attracted much attention.Motivated by the PCR testing data on the Diamond Princess,we propose a novel cure mixture nonparametric model to investigate the detection pattern.It combines a logistic regression for the probability of susceptible subjects with a nonparametric distribution for the detection of infected individuals.Maximum likelihood estimators are proposed.The resulting estimators are shown to be consistent and asymptotically normal.Simulation studies demonstrate that the proposed approach is appropriate for practical use.Finally,we apply the proposed method to PCR testing data on the Diamond Princess to show its practical utility.

关键词： Cure model logistic regression maximum likelihood estimator mixture

Insider Trading with a Random Deadline under Partial Observations:Maximal Principle Method

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Acta Mathematicae Applicatae Sinica 2022年第4期38卷 753-762页

作者： Kai XIAO yong-hui zhou School of Mathematical Sciences Guizhou Normal UniversityGuiyang 550001China School of Big Data and Computer Science Guizhou Normal UniversityGuiyang 550001China

For a revised model of Caldentey and Stacchetti(Econometrica,2010)in continuous-time insider trading with a random deadline which allows market makers to observe some information on a risky asset,a closed form of its market equilibrium consisting of optimal insider trading intensity and market liquidity is obtained by maximum principle method.It shows that in the equilibrium,(i)as time goes by,the optimal insider trading intensity is exponentially increasing even up to infinity while both the market liquidity and the residual information are exponentially decreasing even down to zero;(ii)the more accurate information observed by market makers,the stronger optimal insider trading intensity is such that the total expect profit of the insider is decreasing even go to zero while both the market liquidity and the residual information are decreasing;(iii)the longer the mean of random time,the weaker the optimal insider trading intensity is while the more both the residual information and the expected profit are,but there is a threshold of trading time,half of the mean of the random time,such that if and only if after it the market liquidity is increasing with the mean of random time increasing.

关键词： continuous-time insider trading random deadline partial observations filtering theory maximal principle

Hot Compression Behavior and Tensile Property of a Novel Ni-Co-Based Superalloy Prepared by Electron Beam Smelting Layered Solidification Technology

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Acta Metallurgica Sinica(English Letters) 2024年第2期37卷 283-292页

作者： yong-Chao Gai Rui Zhang Chuan-yong Cui Zi-Jian zhou Yi Tan Yi-zhou zhou Xiao-Feng Sun Key Laboratory of Materials Modification by Laser Ionand Electron Beams(Ministry of Education)School of Materials Science and EngineeringDalian University of TechnologyDalian116024China Shi-Changxu Innovation Center for Advanced Materials Institute of Metal ResearchChinese Academy of SciencesShenyang110016China

The hot compression behavior and tensile strength after compression of a new Ni-Co-based superalloy produced using electron beam smelting layered(EBSL)solidification technology were investigated.Isothermal compression tests were performed at temperatures of 1120℃and 1150℃,with strain rates of 1 s^(-1) and 0.01 s^(-1),reaching a true strain of 0.51.Tensile strength was evaluated at room temperature.The results revealed that this EBSL technology accelerates dynamic recrystallization(DRX),without compromising the strength of alloy.A significant correlation between the volume fraction of DRX and the strain rate was observed,with higher fractions at lower strain rates,leading to higher tensile strength.Additionally,at the same strain rate,the specimens compressed at 1120℃exhibited higher tensile strength due to undissolvedγ′precipitates.After solution and aging heat treatment,the alloy maintained high tensile strength.The results suggested that the EBSL Ni-Co-based superalloy offers excellent prospects for practical applications.

关键词： Ni-Co-based superalloy Hot deformation Electron beam smelting Tensile strength

Two-step homogenization for the effective thermal conductivities of twisted multi-filamentary superconducting strand

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Applied Mathematics and Mechanics(English Edition) 2022年第5期43卷 689-708页

作者： yongbin WANG Huadong yong Youhe zhou Department of Mechanics and Engineering Sciences College of Civil Engineering and MechanicsLanzhou UniversityLanzhou 730000China Key Laboratory of Mechanics on Disaster and Environment in Western China Ministry of Education of ChinaLanzhou UniversityLanzhou 730000China

For the accurate prediction of the effective thermal conductivities of the twisted multi-filamentary superconducting strand,a two-step homogenization method is adopted.Based on the distribution of filaments,the superconducting strand can be decomposed into a set of concentric cylinder layers.Each layer is a two-phase composite composed of the twisted filaments and copper matrix.In the first step of homogenization,the representative volume element(RVE)based finite element(FE)homogenization method with the periodic boundary condition(PBC)is adopted to evaluate the effective thermal conductivities of each layer.In the second step of homogenization,the generalized self-consistent method is used to obtain the effective thermal conductivities of all the concentric cylinder layers.The accuracy of the developed model is validated by comparing with the local and full-field FE simulation.Finally,the effects of the twist pitch on the effective thermal conductivities of twisted multi-filamentary superconducting strand are studied.

关键词： superconducting strand multi-filamentary two-step homogenization effective thermal conductivity