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Bayesian Joint Semiparametric Mean–Covariance Modeling for Longitudinal Data

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Communications in Mathematics and Statistics 2019年第3期7卷 253-267页

作者： Meimei Liu weiping zhang Yu Chen Department of Statistics and Finance School of ManagementUniversity of Science and Technology of ChinaHefei 230026China

Joint parsimonious modeling the mean and covariance is important for analyzing longitudinal data,because it accounts for the efficiency of parameter estimation and easy interpretation of *** main potential risk is that it may lead to inefficient or biased estimators of parameters while misspecification occurs.A good alternative is the semiparametric *** this paper,a Bayesian approach is proposed for modeling the mean and covariance simultaneously by using semiparametric models and the modified Cholesky *** use a generalized prior to avoid the knots selection while using B-spline to approximate the nonlinear part and propose a Markov Chain Monte Carlo scheme based on Metropolis–Hastings algorithm for *** studies and real data analysis show that the proposed approach yields highly efficient estimators for the parameters and nonparametric parts in the mean,meanwhile providing parsimonious estimation for the covariance structure.

关键词： Cholesky decomposition Longitudinal data Bayesian semiparametric model MCMC

Regression Estimation for Longitudinal Data with Nonignorable Intermittent Nonresponse and Dropout

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Communications in Mathematics and Statistics 2022年第3期10卷 383-411页

作者： weiping zhang Dazhi Zhao Yu Chen Department of Statistics and Finance University of Science and Technology of ChinaHefei 230026People’s Republic of China

We mainly focus on regression estimation in a longitudinal study with nonignorable intermittent nonresponse and *** handle the identifiability issue,we take a time-independent covariate as nonresponse instrument which is independent of nonresponse propensity conditioned on other covariates and responses to ensure the identifiability of nonresponse *** nonresponse propensity is assumed to be a parametric model,and the corresponding parameters are estimated by using the generalized method of moments *** the marginal response means are estimated by inverse probability weighting ***,to improve the robustness of estimators,we derive an augmented inverse probability weighting estimator which is shown to be consistent and asymptotically normally *** studies and a real-data analysis show that the proposed approach yields highly efficient estimators.

关键词： Dropout Generalized method of moments Inverse probability weighting Intermittent nonresponse Longitudinal data

A DAMAGE MECHANICS MODEL FOR FATIGUE LIFE PREDICTION OF FIBER REINFORCED POLYMER COMPOSITE LAMINA

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Acta Mechanica Solida Sinica 2011年第5期24卷 399-410页

作者： Wenjing Shi weiping Hu Miao zhang Qingchun Meng Institute of Solid Mechanics School of Aeronautics Science and Engineering BeiHang University Beijing 100191 China

A damage mechanics fatigue life prediction model for the fiber reinforced polymer lamina is established. The stiffness matrix of the lamina is derived by elastic constants of fiber and matrix. Two independent damage degrees of fiber and matrix are introduced to establish constitutive relations with damage. The damage driving forces and damage evolution equations for fiber and matrix are derived respectively. Fatigue tests on 0° and 90° unidirectional laminates are conducted respectively to identify parameters in damage evolution equations of fiber and matrix. The failure criterion of the lamina is presented. Finally, the life prediction model for lamina is proposed.

关键词： fiber reinforced polymer composite lamina continuum damage mechanics fatigue life prediction fiber breakage matrix cracking

Soft initial-rotation and H_∞ robust constant rotational speed control for rotational MEMS gyro

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Journal of Systems Engineering and Electronics 2009年第3期20卷 583-589页

作者： Ma Gaoyin Chen Wenyuan Cui Feng zhang weiping Wang Liqi National Key Lab. of Nano/Micro Fabrication Technology Key Lab. for Thin Film and Microfabrication of Ministry of Education Inst. of Micro and Nano Science and Technology Shanghai Jiaotong Univ.Shanghai 200240 P. R. China

A novel soft initiai-rotation control system and an H∞ robust constant rotational speed controller （RCRSC） for a rotational MEMS （micro-electro-mechanical system） gyro are presented. The soft initial-rotation control system can prevent the possible tumbling down of the suspended rotor and ensure a smooth and fast initial-rotation process. After the initial-rotation process, in order to maintain the rotational speed accurately constant, the RCRSC is acquired through the mixed sensitivity design approach. Simulation results show that the actuation voltage disturbances from the internal carrier waves in the gyro is reduced by more than 15.3 dB, and the speed fluctuations due to typical external vibrations ranging from 10 Hz to 200 Hz can also be restricted to 10^-3 rad/s order.

关键词： micro-electro-mechanicai system gyro rotation mixed sensitivity design H∞ robust controller

基于一种土地利用变化新指标的土地利用变化影响因素分析——以大兴安岭林牧交错区为例

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南阳师范学院学报 2024年第1期23卷 1-8页

作者：白景锋张卫平白云帆南阳师范学院地理科学与旅游学院河南省环境激光遥感技术与应用工程研究中心河南南阳473061 洛南第二高级中学陕西洛南726100 吉林师范大学博达学院吉林四平136000

研究土地利用变化机制,是保障生态脆弱区生态环境良性发展的必然要求。基于土地利用信息图谱构建新指标——土地利用转换度,借助土地利用转移矩阵和土地利用转换度刻画1990—2021年研究区土地利用转移的宏观特征,构建渔网提取土地利用... 详细信息

研究土地利用变化机制,是保障生态脆弱区生态环境良性发展的必然要求。基于土地利用信息图谱构建新指标——土地利用转换度,借助土地利用转移矩阵和土地利用转换度刻画1990—2021年研究区土地利用转移的宏观特征,构建渔网提取土地利用转换度,分析其空间自相关性,并用地理加权回归(GWR)分析研究区土地利用变化的影响因素,为林牧交错区社会经济发展服务。研究发现:(1)1990—2021年,研究区土地利用类型的宏观格局变化不大,林地和草地是该区域的主要用地类型,林地主要分布在东部和北部的山区,草地主要分布在西南部,耕地主要分布于山地和草原交接的地区及河谷地带。(2)1990—2021年林地呈现增加趋势,草地逐年减少,耕地和建设用地缓慢增加。(3)草地、耕地和林地是该地区土地利用变动的主要类型,以草地转出最多,主要转换为林地和耕地。(4)土地利用转换度有显著空间自相关,存在明显的高高聚集和低低聚集。转换频繁区呈倒“C”字形,分布在大兴安岭西部山区与草地过渡带,即海拔700~900 m的地带。(5)GWR分析发现坡度、气温变化、人均GDP变化是影响该区土地利用的主要因素,人均GDP增加会降低土地利用转换度,而其他因素增加会导致土地利用转换加速。(6)土地利用转换度是一种可靠的土地利用变化度量指标,能够将空间和时间融合反映土地利用状态的变化强度。

关键词：新指标林牧交错区土地利用影响因素

A Sub-100 mg Electromagnetically Driven Insect-inspired Flapping-wing Micro Robot Capable of Liftoff and Control Torques Modulation

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Journal of Bionic Engineering 2020年第6期17卷 1085-1095页

作者： Chenyang Wang weiping zhang Yang Zou Ran Meng Jiaxin Zhao Mingchen Wei National Key Laboratory of Science and Technology on Micro/Nano Fabrication School of Electronic Information and Electrical EngineeringShanghai Jiao Tong UniversityShanghai 200240China

Inspired by the unique,agile and efficient flapping flight of insects,we present a novel sub-100 mg,electromagnetically driven,tailless,flapping-wing micro *** robot utilizes two optimized electromagnetic actuators placed back to back to drive two wings separately,then kinematics of each wing can be independently controlled,which gives the robot the ability to generate all three control torques of pitch,roll and yaw for *** quantify the performance of the robot,a simplified aerodynamic model is used to estimate the generated lift and torques,and two customized test platforms for lift and torque measurement are built for this *** mean lift generated by the robot is measured to be proportional to the square of the input voltage *** three control torques are measured to be respectively proportional to three decoupled parameters of the control voltages,therefore the modulation of three control torques for the robot is independent,which is helpful for the further controlled *** these measured results fit well with the calculated results of the aerodynamic ***,with a total weight of 96 mg and a wingspan of 3.5 cm,this robot can generate sufficient lift to take off.

关键词： insect-inspired insect-scale micro robot FMAV electromagnetic actuation

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对称反向CW型倍压整流电路性能分析

北方工业大学学报 2024年第3期36卷 62-66页

作者：毛鹏左玉阳张晓强张卫平北方工业大学信息学院北京100144

为了降低高压变压器中匝数比过大带来的影响,业界普遍采用变压器加倍压整流电路的多级升压方式实现高电压输出。本文通过研究对称反向高压倍加器(Cockcroft-Walton accelerator,CW)型倍压整流电路的工作原理,分析了输入电压频率、负载... 详细信息

为了降低高压变压器中匝数比过大带来的影响,业界普遍采用变压器加倍压整流电路的多级升压方式实现高电压输出。本文通过研究对称反向高压倍加器(Cockcroft-Walton accelerator,CW)型倍压整流电路的工作原理,分析了输入电压频率、负载和电容值对对称反向CW型倍压整流电路输出电压压降和输出电压纹波的影响。研究发现该电路适用于高频率输入电压、轻负载、大容值电容的工作场景,可以根据确定的输入电压、输出电压、以及负载大小等参数,来选择合适的电压频率和电容,使得输出电压压降和输出电压纹波达到最小。

关键词：倍压整流电路电压压降电压纹波轻负载大容值电容

Polo-like kinase 1 suppresses lung adenocarcinoma immunity throughnecroptosis

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肿瘤学研究(英文) 2023年第6期31卷 937-953页

作者： PENGCHENG zhang XINGLONG zhang YONGFU ZHU YIYI CUI JING XU weiping zhang Department of Oncology The Third Affiliated Hospital of Zhejiang Chinese Medical UniversityHangzhouChina Department of Oncology Anhui Zhongke Gengjiu HospitalHefeiChina Department of Oncology The First Affiliated Hospital of Anhui University of Chinese MedicineHefeiChina Department of Biochemistry and Molecular Biology School of Integrated Chinese and Western MedicineAnhui University of Chinese MedicineHefeiChina

Polo-like kinase 1(PLK1)plays a crucial role in cell mitosis and has been associated with ***,the role of PLK1 and necroptosis in lung adenocarcinoma(LA)remains *** this study,we analyzed The Cancer Genome Atlas(TCGA)and Genotype-Tissue Expression databases to evaluate the prognostic value and mechanistic role of PLK1 in ***1 was found to be highly expressed in LA and was positively associated with advanced disease staging and poor survival *** enrichment analysis showed that PLK1 was involved in cell mitosis,neurotransmitter transmission,and drug *** analysis using single-sample gene set enrichment analysis and ESTIMATE algorithm revealed a correlation between PLK1 expression and immune infiltration in *** of PLK1 using miRNA transfection in LA cells reduced cell proliferation and increased apoptosis,as well as upregulating the expression of necroptosis-related proteins,such as RIPK1,RIPK3,and ***,nude mouse transplantation tumor experiments demonstrated that silencing PLK1 reduced the growth capacity of LA *** findings suggest that PLK1 plays a critical role in LA progression by regulating necroptosis and immune infiltration,and may serve as a potential therapeutic target for ***,PLK1 expression can be used as a prognostic biomarker for LA patients.

关键词： PLK1 Lung adenocarcinoma Prognosis biomarker Immune infiltration Necroptosis

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男童尿道损伤专家共识(2023)

中华小儿外科杂志 2024年第4期45卷 289-295页

作者：中华医学会小儿外科分会泌尿学组张潍平许帅宋宏程不详国家儿童医学中心首都医科大学附属北京儿童医院泌尿外科北京100045 首都医科大学附属北京儿童医院新疆维吾尔自治区儿童医院

尿道损伤仅次于肾脏损伤,在泌尿生殖系统的损伤中发病率居第二位[1]。基于生理解剖的特点,儿童尿道损伤程度往往重于成人,尤其是骨盆骨折相关的尿道损伤(pelvic fracture-associated urethral injury,PFUI),其治疗更加复杂,并发症率更... 详细信息

尿道损伤仅次于肾脏损伤,在泌尿生殖系统的损伤中发病率居第二位[1]。基于生理解剖的特点,儿童尿道损伤程度往往重于成人,尤其是骨盆骨折相关的尿道损伤(pelvic fracture-associated urethral injury,PFUI),其治疗更加复杂,并发症率更高。目前儿童尿道损伤的诊治多借鉴成人诊治原则,在治疗上许多方面存在争议[1-3]。为了提高儿童尿道损伤的诊治水平,规范儿童尿道损伤的诊治流程,中华医学会小儿外科分会泌尿学组在结合国内外诊治现状及各专家意见的基础上制定了本共识,因男童比女童尿道损伤更多发,且处理原则和方法不同,本共识仅适用于男童尿道损伤。

关键词：尿道损伤泌尿生殖系统中华医学会小儿外科骨盆骨折诊治原则诊治现状生理解剖