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Reconstructing and forecasting the COVID-19 epidemic in the United States using a 5-parameter logistic growth model

Global Health Research and Policy 2020年第1期5卷 221-227页

作者： ding-geng chen Xinguang chen Jenny K.chen School of Social Work University of North CarolinaTate-Turner Kuralt Building 548-CCB#3550Chapel HillNC 27599USA Department of Statistics University of PretoriaPretoriaSouth Africa Department of Epidemiology University of FloridaGainesvilleUSA Department of Statistics and Data Science Cornell UniversityIthacaUSA

Background:Many studies have modeled and predicted the spread of COVID-19(coronavirus disease 2019)in the *** data that begins with the first reported ***,the shortage of testing services to detect infected persons makes this approach subject to error due to its underdetection of early cases in the *** new approach overcomes this limitation and provides data supporting the public policy decisions intended to combat the spread of COVID-19 ***:We used Centers for Disease Control and Prevention data documenting the daily new and cumulative cases of confirmed COVID-19 in the *** January 22 to April 6,2020,and reconstructed the epidemic using a 5-parameter logistic growth *** fitted our model to data from a 2-week window(i.e.,from March 21 to April 4,approximately one incubation period)during which large-scale testing was being *** parameters obtained from this modeling,we reconstructed and predicted the growth of the epidemic and evaluated the extent and potential effects of ***:The data fit the model *** estimated daily growth rate was 16.8%overall with 95%CI:[15.95,17.76%],suggesting a doubling period of 4 *** on the modeling result,the tipping point at which new cases will begin to decline will be on April 7th,2020,with a peak of 32,860 new cases on that *** the end of the epidemic,at least 792,548(95%CI:[789,162,795,934])will be infected in the *** on our model,a total of 12,029 cases were not detected between January 22(when the first case was detected in the U.S.)and April ***:Our findings demonstrate the utility of a 5-parameter logistic growth model with reliable data that comes from a specified period during which governmental interventions were appropriately *** informing public health decision-making,our model adds a tool for more faithfully capturing the spread of the COVID-19 epidemic.

关键词： COVID-19 Epidemics Disease dynamics Population-based model Logistic growth model Prediction Reconstruction Under-detection Tipping point USA

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Analysis of correlated data with feedback for time-dependent covariates in psychiatry research

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General Psychiatry 2020年第5期33卷 374-377页

作者： Elsa Vazquez Arreola Jeffrey R Wilson ding-geng chen School of Mathematical and Statistical Sciences Arizona State UniversityTempeArizonaUSA Department of Economics W.P.Carey School of BusinessArizona State UniversityTempeArizonaUSA School of Social Work and Department of Biostatistics University of North Carolina at Chapel HillChapel HillNorth CarolinaUSA

In studies on psychiatry and neurodegenerative diseases,it is common to have data that are correlated due to the hierarchical structure in data collection or to repeated measures on the subject ***,the feedback effect created due to time-dependent covariates in these studies is often overlooked and seldom *** article reviews the methodological development of feedback effects with marginal models for longitudinal data and discusses their implementation.

关键词： diseases psy measures

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使用免费软件R进行精神病学研究的Meta分析（英文）

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上海精神医学 2015年第3期27卷 195-199页

作者： chen DG School of Social Work University of North Carolina at Chapel Hill

本文对meta分析(meta-analysis,MA)作了简要概述,并着重于经典的固定效应和随机效应MA模型。文章以综合分析5项使用拉莫三嗪治疗双相障碍抑郁发作的研究的公开数据为范例,介绍了MA模型的应用及免费软件R在meta分析中的使用方法,该meta... 详细信息

本文对meta分析(meta-analysis,MA)作了简要概述,并着重于经典的固定效应和随机效应MA模型。文章以综合分析5项使用拉莫三嗪治疗双相障碍抑郁发作的研究的公开数据为范例,介绍了MA模型的应用及免费软件R在meta分析中的使用方法,该meta分析证实拉莫三嗪的效果优于安慰剂,且有统计学显著性,而在单个的研究中此优势并不明显。

关键词： meta分析固定效应模型随机效应模型双相情感障碍拉莫三嗪

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Comparative Study of Four Methods in Missing Value Imputations under Missing Completely at Random Mechanism

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Open Journal of Statistics 2014年第1期4卷 27-37页

作者： Michikazu Nakai ding-geng chen Kunihiro Nishimura Yoshihiro Miyamoto chool of Nursing & Department of Biostatistics and Computational Biology School of Medicine University of Rochester Medical Center New York USA Department of Preventive Medicine and Epidemiologic Informatics National Cerebral and Cardiovascular Center Suita Japan

In analyzing data from clinical trials and longitudinal studies, the issue of missing values is always a fundamental challenge since the missing data could introduce bias and lead to erroneous statistical inferences. To deal with this challenge, several imputation methods have been developed in the literature to handle missing values where the most commonly used are complete case method, mean imputation method, last observation carried forward (LOCF) method, and multiple imputation (MI) method. In this paper, we conduct a simulation study to investigate the efficiency of these four typical imputation methods with longitudinal data setting under missing completely at random (MCAR). We categorize missingness with three cases from a lower percentage of 5% to a higher percentage of 30% and 50% missingness. With this simulation study, we make a conclusion that LOCF method has more bias than the other three methods in most situations. MI method has the least bias with the best coverage probability. Thus, we conclude that MI method is the most effective imputation method in our MCAR simulation study.

关键词： Missing Data Imputation MCAR Complete Case LOCF

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Cusp Catastrophe Polynomial Model: Power and Sample Size Estimation

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Open Journal of Statistics 2014年第10期4卷 803-813页

作者： ding-geng chen Xinguang chen Feng Lin Wan Tang Yuhlong Lio Yuanyuan Guo Center of Research School of Nursing University of Rochester Medical Center Rochester NY USA Department of Biostatistics and Computational Biology University of Rochester Medical Center Rochester NY USA Institute of Data Sciences University of Rochester Rochester NY USA Department of Epidemiology University of Florida Gainesville FL USA School of Public Health Wuhan University Wuhan China AD-CARE Department of Psychiatry University of Rochester Medical Center Rochester NY USA Department of Mathematical Sciences University of South Dakota Vermillion SD USA Department of Statistics Central South University Changsha China

Guastello’s polynomial regression method for solving cusp catastrophe model has been widely applied to analyze nonlinear behavior outcomes. However, no statistical power analysis for this modeling approach has been reported probably due to the complex nature of the cusp catastrophe model. Since statistical power analysis is essential for research design, we propose a novel method in this paper to fill in the gap. The method is simulation-based and can be used to calculate statistical power and sample size when Guastello’s polynomial regression method is used to do cusp catastrophe modeling analysis. With this novel approach, a power curve is produced first to depict the relationship between statistical power and samples size under different model specifications. This power curve is then used to determine sample size required for specified statistical power. We verify the method first through four scenarios generated through Monte Carlo simulations, and followed by an application of the method with real published data in modeling early sexual initiation among young adolescents. Findings of our study suggest that this simulation-based power analysis method can be used to estimate sample size and statistical power for Guastello’s polynomial regression method in cusp catastrophe modeling.

关键词： Cusp Catastrophe Model Polynomial Regression Method Statistical Power Analysis Sample Size Determination

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Parameter Estimations for Generalized RayleighDistribution under Progressively Type-I IntervalCensored Data

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Open Journal of Statistics 2011年第2期1卷 46-57页

作者： Y. L. Lio ding-geng chen Tzong-Ru Tsai 不详

In this paper, inference on parameter estimation of the generalized Rayleigh distribution are investigated for progressively type-I interval censored samples. The estimators of distribution parameters via maximum likelihood, moment method and probability plot are derived, and their performance are compared based on simulation results in terms of the mean squared error and bias. A case application of plasma cell myeloma data is used for illustrating the proposed estimation methods.

关键词： Maximum Likelihood Estimate Method of Moments EM Algorithm Type-I Interval Censoring

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Green disposal of waste smartphone protective film:Efficiency,mechanism,bench-scale test and secondary waste reutilization

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Journal of Environmental Sciences 2025年第5期151卷 692-702页

作者： Jiangyao chen Shunyu ding chenxu Gao Canhui chen Taicheng An Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control Guangdong Technology Research Center for Photocatalytic Technology Integration and Equipment EngineeringInstitute of Environmental Health and Pollution ControlGuangdong University of TechnologyGuangzhou 510006China Guangzhou Key Laboratory of Environmental Catalysis and Pollution Control Guangdong-Hong Kong-Macao Joint Laboratory for Contaminants Exposure and HealthSchool of Environmental Science and EngineeringGuangdong University of TechnologyGuangzhou 510006China

The manufacture and obsolescence of smartphones produce numerous waste plastic accessories(e.g.,waste smartphone protective film(WSPF)),possessing immense potential for ***,available recycling technologies have limitations such as substrate damage and secondary pollutant *** present study aimed to develop a green disposal method that not only recycled polyethylene terephthalate(PET)from WSPF,but also reused the stripped polyacrylate(PAA)adhesive as an adsorbent to reduce solid waste *** the WSPF was treated in 1 mol/L NaOH solution at 90°C,the PAA hydrolyzed to two main by-products of 1-butanol and 2-ethylhexanol,weakening the binding strength between PAA and PET and then efficient separation of *** bench-scale test revealed that over 97.2%of detachment efficiency toward PAA was achieved during continuous treatment of 17 batches of WSPF(200 g for each)without supplement of NaOH and generation of ***,the economic evaluation indicated that the recycling method would generate a net profit margin of 647%for the second year without considering the incurrence of new cost and ***,the pyrolysis of waste PAA enabled its conversion into potential adsorbent,which showed 2 to 4 times enhanced adsorption capacity toward styrene and ethyl acetate after modification with NaOH *** study provides a green method for recycling waste plastics and inspires a referable solution for solid waste treatment in the smartphone industry.

关键词： Smartphone accessory Waste protective film Green recycle Polyethylene terephthalate Polyacrylate Adsorbent

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Quantum purification for coherent states and its application

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Science China(Physics,Mechanics & Astronomy) 2025年第2期68卷 37-50页

作者： Lei Wang geng Chai Zhengwen Cao Xinlei chen Kexin Liang Jinye Peng Laboratory of Quantum Information and Technology School of Information Science and TechnologyNorthwest UniversityXi'an 710127China

The inevitable decoherence of quantum states leaks information to the environments and reduces the practical performance of quantum-information *** purification of coherent states provides an easy-to-implement approach to decouple from the environments utilizing the correlation of several ***,repeated transmission of quantum states reduces the randomness of the collectivity and generates security *** this paper,we propose a modified purification scheme and apply it to the continuous-variable quantum secure direct communication(CV-QSDC)protocol based on coherent *** designed purification scheme improves the security capacity of communication systems through the effective suppression of excess noises,accompanied by the maintenance of source-side *** conduct a proof-of-principle experiment of the purification scheme in the CV-QSDC *** appearance of transmitted quantum states in phase space and two-dimensional Gaussian distributions have high goodness of fit at two *** security capability of this system is improved by 43.6%as the excess noise is reduced to 0.58 times the original noise by purification.

关键词： quantum purification coherent state quantum secure direct communication

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Unraveling the reaction mechanism of high reversible capacity CuP_(2)/C anode with native oxidation PO_(x) component for sodium-ion batteries

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Chinese Chemical Letters 2025年第1期36卷 574-578页

作者： Huixin chen chen Zhao Hongjun Yue Guiming Zhong Xiang Han Liang Yin ding chen State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body College of Mechanical and Vehicle EngineeringHunan UniversityChangsha 410082China CAS key Laboratory of Design and Assembly of Functional Nanostructures and Fujian Provincial Key Laboratory of NanomaterialsFujian Institute of Research on the Structure of MatterChinese Academy of SciencesFuzhou 350002China College of Materials Science and Engineering Co-Innovation Center of Efficient Processing and Utilization of Forest ResourcesNanjing Forestry UniversityNanjing 210037China Laboratory of Advanced Spectro-electrochemistry and Li-ion Batteries Dalian Institute of Chemical PhysicsChinese Academy of SciencesDalian 116023China Institute of Physics Chinese Academy of SciencesBeijing 100190China Xiamen Key Laboratory of Rare Earth Photoelectric Functional Materials Xiamen Institute of Rare Earth MaterialsHaixi institutesChinese Academy of SciencesXiamen 361021China

Phosphorus-based anode is a promising anode for sodium-ion batteries(SIBs)due to its high specific capacity,however,suffers from poor electronic conductivity and unfavorable electrochemical *** metals such as copper(Cu)into phosphorus has been demonstrated to not only improve the electronic conductivity but also accommodate the volume change during cycling,yet the underline sodiation mechanism is not ***,take a copper phosphide and reduced graphene oxide(CuP_(2)/C)composite as an example,which delivers a high reversible capacity of>900 mAh/***,it is revealed that the native oxidation PO_(x)components of the CuP_(2)/C composite show higher electrochemical reversibility than the bulk Cu P_(2),based on a quantitative analysis of high-resolution solid-state^(31)P NMR,ex-situ XPS and synchrotron X-ray diffraction characterization *** sodiation products Na_(3)PO_(4) and Na_(4)P_(2)O_(7) derived from PO_(x) could react with Na-P alloys and regenerate to PO_(x) during charge process,which probably accounts for the high reversible capacity of the Cu P_(2)/C *** findings also illustrate that the phosphorus transforms into nanocrystalline Na_(3)P and Na_(x)P alloys,which laterally shows crystallization-amorphization evolution process during cycling.

关键词： CuP_(2)/C composite POx component Reaction mechanism Solid-state NMR Sodium-ion batteries

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Edge-aware Feature Aggregation Network for Polyp Segmentation

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Machine Intelligence Research 2025年第1期22卷 101-116页

作者： Tao Zhou Yizhe Zhang geng chen Yi Zhou Ye Wu Deng-Ping Fan PCA Lab Key Laboratory of Intelligent Perception and Systems for High-dimensional Information of Ministry of EducationSchool of Computer Science and EngineeringNanjing University of Science and TechnologyNanjing210094China School of Computer Science and Engineering Northwestern Polytechnical University(NPU)Xi’an710129China School of Computer Science and Engineering Southeast UniversityNanjing211189China Computer Vision Lab ETH ZürichZürich8092Switzerland

Precise polyp segmentation is vital for the early diagnosis and prevention of colorectal cancer(CRC)in clinical ***,due to scale variation and blurry polyp boundaries,it is still a challenging task to achieve satisfactory segmentation performance with different scales and *** this study,we present a novel edge-aware feature aggregation network(EFA-Net)for polyp segmentation,which can fully make use of cross-level and multi-scale features to enhance the performance of polyp ***,we first present an edge-aware guidance module(EGM)to combine the low-level features with the high-level features to learn an edge-enhanced feature,which is incorporated into each decoder unit using a layer-by-layer ***,a scale-aware convolution module(SCM)is proposed to learn scale-aware features by using dilated convolutions with different ratios,in order to effectively deal with scale ***,a cross-level fusion module(CFM)is proposed to effectively integrate the cross-level features,which can exploit the local and global contextual ***,the outputs of CFMs are adaptively weighted by using the learned edge-aware feature,which are then used to produce multiple side-out segmentation *** results on five widely adopted colonoscopy datasets show that our EFA-Net outperforms state-of-the-art polyp segmentation methods in terms of generalization and *** implementation code and segmentation maps will be publicly at https://***/taozh2017/EFANet.

关键词： Colorectal cancer polyp segmentation edge-aware guidance module scale-aware convolution module cross-level fusion module

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