新冠肺炎传播动力学建模及预测

为了深入研究新冠肺炎传播趋势和传播风险,根据新冠肺炎的传播特点,考虑政府管控和个人防护等措施,在经典传染病SIR模型的基础上,引入低风险群体,提出一种新冠肺炎传播动力学模型SLIR,并对模型的平衡点、稳定性和分岔等复杂动力学行为进行分析,揭示新冠肺炎传播机理.为了提高该模型的疫情预测精度,以美国新冠肺炎的真实数据为基础,使用最小二乘法对模型参数进行分段估计.最后利用该模型对美国新冠肺炎进行预测和分析,仿真结果表明,相比于传统SIR模型,该模型能较好地对美国疫情发展趋势做出预测,官方公布的实际数据也可进一步验证模型的有效性. SLIR模型可以有效仿真新冠肺炎传播,并为政府选择合适的防控措施提供技术支撑.     

从《国家网络安全事件应急预案》看我国网络安全事件应急体系

2020年伊始,新型冠状病毒肺炎疫情突然暴发,并在全球范围流行.多个国家的APT攻击组织都发起了以新冠疫情为诱饵主题的高级威胁攻击.互联网在我国新冠肺炎疫情防控方面发挥了积极的支撑作用.但随之而来的网络攻击、安全漏洞、数据泄露、网络诈骗、勒索病毒等网络安全风险威胁日益凸显,为我国网络安全防护工作带来巨大压力.网络安全应...     

新冠肺炎疫情趋势预测模型

2019年新型冠状病毒肺炎(corona virus disease 2019,COVID-19)的爆发对人们的健康和生活造成了极大的危害和影响.预测疫情的发展趋势可帮助人们提前制定应对措施.SEIR模型是经典的传染病模型之一,由于该模型中病毒传染率为常数,难以对新冠肺炎传播情况进行准确建模并完成疫情趋势预测.针对此问...     

新冠肺炎疫情对我国新型基础设施发展影响分析

2月21日,中央政治局在研究新冠肺炎疫情防控工作会议中强调"加大试剂、药品、疫苗研发支持力度,推动生物医药、医疗设备、5G网络、工业互联网等加快发展"。3月4日,中央政治局常委会在研究当前新冠肺炎疫情防控和稳定经济社会运行重点工作时指出"要加快5G、数据中心等新型基础设施建设进度"。新一代信息通信技术支撑新型基础设施建设并在疫情防控和复工复产中发挥的重要作用受到中央政治局高度重视。疫情赋予新型基础设施更加重大使命,当前需要全局考虑、统筹设计,协同推进新型基础设施核心技术研究与建设部署运行。     

应用易感者-暴露者-感染者-康复者模型对COVID-19的传播及防御措施分析

该文通过易感者-暴露者-感染者-康复者模型分析新型冠状病毒肺炎(COVID-19)在人群中传播的过程,及不同防御措施对疫情曲线的影响,针对结果为疫情的防控提出建议.根据人群接触网络模式对易感者-暴露者-感染者-康复者模型进行改进,加入隔离、中医药干预等模型元素,构建符合新冠肺炎传播特点的数学模型.将影响新型冠状病毒肺炎...     

环境感知的新冠肺炎传播态势的建模与分析

针对现有传播模型没有考虑个体所在环境对个体感染病毒的影响以及经典传播模型无法很好地刻画个体特征的问题,提出了基于环境感知的病毒传播模型(EA-SIR).首先,引入个体接触矩阵来描述个体之间的接触情况,推导基于环境感知的个体染病概率,建立EA-SIR的微分方程组;然后,推导EA-SIR的基本再生数及其上界.EA-SIR的基本再生数上界小于或等于经典SIR模型,说明病毒在EA-SIR中更难传播,实际上人们强烈的自我保护意识有利于阻断病毒的传播,因此理论上EA-SIR更适用于刻画病毒的传播.最后,使用"钻石公主"号以及国内四个城市的疫情数据进行实验,以平均绝对误差(MAE)为评价标准.仿真实验的结果表明,EA-SIR能够较好地刻画新冠肺炎疫情的传播态势.     

环境感知的新冠肺炎传播态势的建模与分析

针对现有传播模型没有考虑个体所在环境对个体感染病毒的影响以及经典传播模型无法很好地刻画个体特征的问题,提出了基于环境感知的病毒传播模型(EA-SIR).首先,引入个体接触矩阵来描述个体之间的接触情况,推导基于环境感知的个体染病概率,建立EA-SIR的微分方程组;然后,推导EA-SIR的基本再生数及其上界.EA-SIR的基本再生数上界小于或等于经典SIR模型,说明病毒在EA-SIR中更难传播,实际上人们强烈的自我保护意识有利于阻断病毒的传播,因此理论上EA-SIR更适用于刻画病毒的传播.最后,使用"钻石公主"号以及国内四个城市的疫情数据进行实验,以平均绝对误差(MAE)为评价标准.仿真实验的结果表明,EA-SIR能够较好地刻画新冠肺炎疫情的传播态势.     

基于SEIR模型的新型冠状病毒肺炎疫情分析

对新型冠状病毒肺炎的传播规律进行研究,为传染病防控提供科学依据.基于每日发布的新冠肺炎确诊人数数据集,采用经典的SEIR(Susceptible-Exposed-Infected-Recovered)传染病动力学模型模拟疫情传播过程;利用最小二乘法对感染系数β和恢复系数γ进行参数估计;通过过滤原始数据集、优化感染人群初始值I0和恢复系数γ等方法进一步提高模型预测的准确率.该方法能够合理地预测疫情确诊人数和疫情拐点,对全国、湖北省确诊人数的预测误差率分别不超过2.04％、1.25％,对于疫情防控具有实用价值.     

基于人际关系的传染病传播仿真模型研究

通过建立一种基于人际关系的传染病传播仿真模型对传染病传播过程以及预测在相关防控措施下疫情发展的趋势进行研究。基于人际关系描述个体间的接触与交互,以个体为单位建立仿真模型,根据中国卫健委平台收集武汉地区COVID-19疫情的初期数据调整模型参数,估算基本再生数（R0）验证模型,并模拟不同疫情防控手段的场景,探讨不同干预措施下疫情传播的趋势。建立的基于人际关系的传染病传播模型首先模拟了武汉疫情初期的传播过程,估算武汉封城前COVID-19的R0;然后对扬州疫情发展趋势进行了初步预测,发现疫情已进入可控阶段。通过探讨在人口密集接触场所（以学校为例）中不同的干预措施对疫情发展的影响,针对学生秋季开学提出相关防控意见,讨论了个体在社交接触网络中的社交移动距离对疫情传播的影响。     

AI破疫:依图捕捉蛛丝马迹

疫情期间,人工智能在众多场景中实现了落地应用。其中,依图医疗围绕新冠肺炎打造的智能评价系统,可以辅助医生分析疑似患者的CT影像,进而做出初步诊断。此外,依图医疗推出的小依医生、区域传染病智能防控解决方案同样为疫情防控提供了科技支撑。国内新型冠状病毒感染的肺炎(以下简称新冠肺炎)疫情爆发后,收治患者成为头等大事,尤其对于武汉市而言,提高收治能力迫在眉睫。     

The analysis of isolation measures for epidemic control of COVID-19

This paper proposes a susceptible exposed infectious recovered model (SEIR) with isolation measures to evaluate the COVID-19 epidemic based on the prevention and control policy implemented by the Chinese government on February 23, 2020. According to the Chinese government’s immediate isolation and centralized diagnosis of confirmed cases, and the adoption of epidemic tracking measures on patients to prevent further spread of the epidemic, we divide the population into susceptible, exposed, infectious, quarantine, confirmed and recovered. This paper proposes an SEIR model with isolation measures that simultaneously investigates the infectivity of the incubation period, reflects prevention and control measures and calculates the basic reproduction number of the model. According to the data released by the National Health Commission of the People’s Republic of China, we estimated the parameters of the model and compared the simulation results of the model with actual data. We have considered the trend of the epidemic under different incubation periods of infectious capacity. When the incubation period is not contagious, the peak number of confirmed in the model is 33,870; and when the infectious capacity is 0.1 times the infectious capacity in the infectious period, the peak number of confirmed in the model is 57,950; when the infectious capacity is doubled, the peak number of confirmed will reach 109,300. Moreover, by changing the contact rate in the model, we found that as the intensity of prevention and control measures increase, the peak of the epidemic will come earlier, and the peak number of confirmed will also be significantly reduced. Under extremely strict prevention and control measures, the peak number of confirmed cases has dropped by nearly 50%. In addition, we use the EEMD method to decompose the time series data of the epidemic, and then combine the LSTM model to predict the trend of the epidemic. Compared with the method of directly using LSTM for prediction, more detailed information can be obtained.

     

COVID-19智能体模型及城市疫情封控措施评价研究

国内新冠肺炎(COVID-19)疫情平稳后,外来输入携带病毒的人与货物可能导致国内出现疫情小幅反弹.针对各地疫情反弹后城市采取封控措施的尺度对城市运行的影响问题,结合多智能体仿真、复杂网络模型中的小世界网络与GIS技术,构建了COVID-19城市空间智能体模型,通过马尔科夫蒙特卡洛方法(Markov chain Mon...     

关于新型冠状病毒肺炎一类基于CCDC统计数据的 随机时滞动力学模型

科学地预测新型冠状病毒肺炎疫情发展趋势对疫情防控至关重要.本文对中国疾病预防控制中心(CCDC)发布[1]的数据进行了分析,给出了关于新型冠状病毒肺炎的一些可能的统计模型:传播链中连续病例的发病时间间隔分布、感染至发病的时间间隔分布和发病至住院的间隔时间3个分布,并形成了感染至确诊的时间间隔分布表达.结合CCDC统计数据和程晋团队的时滞动力学模型(TDD-NCP模型),本文发展了新的随机时滞动力学模型(Fudan-CCDC模型),并给出了参数反演结果与疫情分析.     

The governance strategies for public emergencies on social media and their effects: a case study based on the microblog data

Since the 1980s, the development of information and communication technologies (ICTs) has greatly changed people’s modes of production and lifestyle, and it has also had a significant influence on traditional social structures. Microblogs – a type of social media application such as Twitter or Weibo – have served as an important platform for network governance in some local governments in China. This study makes an attempt to answer the following questions: What types of strategies should governments implement on social media platforms during public emergencies? What are the effects of these strategies? Based on the case of the Shifang Incident, which was a large-scale environmental protest that occurred in Shifang, China in 2012, we analyze all the messages posted during the incident on the official microblog of the Shifang government and examine the public feedback by using an online big data analysis tool. In line with the time sequence and the extent of the conflict, we divide the Shifang Incident into three phases: the fermentation period, the confrontation period, and the digestion period. In addition, we classify government strategies on social media into five categories: introducing, appealing, explaining, rumor-refuting, and decision-making. The analysis results show that different government strategies are applied to different phases of the incident and that the responses of the public also vary during different periods.     

Group processes and interoperability: A longitudinal case study analysis of the UK's civil contingency response to Covid-19

Our case study explored a Local Resilience Forum's (LRF) civil contingency response to COVID-19 in the United Kingdom. We undertook 19 semistructured ethnographic longitudinal interviews, between March 25, 2020 and February 17, 2021, with a Director of a Civil Contingencies Unit and a Chief Fire Officer who both played key roles within their LRF. Within these interviews, we focused on their strategic level decision-making and how their relationship with national government impacted on local processes and outcomes. Using a form of grounded theory, our data describe the chronological evolution of an increasingly effective localized approach toward outbreak control and a growing resilience in dealing with concurrent emergency incidents. However, we also highlight how national government organizations imposed central control on aspects of the response in ways that undermined or misaligned with local preparedness. Thus, during emergencies, central governments can undermine the principle of subsidiarity and damage the ways in which LRFs can help scaffold local resilience. Our work contributes to the theoretical understanding of the social psychological factors that can shape the behaviour of responder agencies during a prolonged crisis. In particular, the implications of our analysis for advancing our conceptual understanding of strategic decision-making during emergencies are discussed.     

The Improvement of Segmentation of Lung Pathologies and Pleural Effusion on CT-scans of Patients with Covid-19

Programming and Computer Software - In 2020 the outbreak of Covid-19 influenced lives of billions of people all around the globe and motivated governments of different countries to revisit the...     

论电子政务建设中的信息资源所有权问题

信息资源作为当今世界三大资源之一,广泛存在于经济、社会各个领域和部门,对国家和民族的发展,对人们工作、生活至关重要,成为国民经济和社会发展的重要战略资源。它的开发和利用是电子政务体系的核心内容。在对我国部分大型电子政务工程的研究和实际参与中,发现其中存在着诸如项目受限于下属部门的局部需求、缺乏宏观需求,业务与信息化两张皮,无人了解信息资源全局等各种问题。究其根本原因在于政府信息资源的所有权分属于各个下属部门之内,形成了部门割据现象。针对这一问题,根据党和国家提出的建设服务型政府理念,借鉴了包括大学仪器共享等资源共享思路,按照服务型业务模式对资源的非占有性的思路,提出应贯彻和落实“管用分离”的理念,采取明确政府机关的信息资源所有权、建立专职的信息管理部门、信息资源的逐步固化等措施进行保障的解决思路。     

2014年中国高性能计算机发展现状分析与展望

本文根据2014 年11 月发布的中国高性能计算机TOP100 排行榜的数据,对国内高性能计算机的发展现状从总体性能、制造商、行业领域等方面进行了深入分析。我们发现, 由于天河二号超级计算机的发布,中国TOP100 的平均Linpack 性能已经从两年前的落后一年变为比国际TOP500 平均Linpack 性能高的局面,且TOP100 的入门性能门槛也第一次超过TOP500。在此基础上,根据十三届排行榜积累的性能数据和能够得到的其他公开历史数据,对未来几年中国大陆高性能计算机的发展趋势进行了分析预测。根据新的数据和实际情况,经修正后我们认为,累计Linpack 性能将在2015 年到2016 年间达到100Petaflops, 比我们原来预期的晚;峰值100Petaflops 的机器将在2015 年到2016 年间出现;峰值Exaflops 的机器将在2019 年到2020 年间出现,比我们原来预期的晚2 年。单台机器峰值超过累计Linpack 性能的情况出现在2018 到2019 年间。     

Modeling the influence of risk factors and chronic diseases on the development of strokes and peripheral arterial-vascular disease

Several chronic diseases and risky lifestyles have become an important social burden in many countries around the world, a problem which should not be underestimated. The situation is even more worrying when we take into account their influence on serious health complications that can threaten patients’ lives or significantly reduce their quality of life. The presented modeling-and-simulation study enables us to estimate the number of patients with type-2 diabetes, hypercholesterolemia and hypertension, obese and smoking people and the influence of these conditions on the development of strokes and peripheral arterial-vascular diseases. In addition, an estimate of treatment costs makes it possible to evaluate the social burden and provide information about the potential savings resulting from treating intensive chronic diseases.     

Adaptive morphological filters for color image enhancement

In this paper, we investigate the performance of an adaptive morphological filter on color image processing, and we develop fast algorithms for the operation. The adaptive filter is based on a new type of opening (NOP) and closing operators (NCP). The operational window of the NOP and NCP can alter its shape according to the local geometry of the processed images. Our experimental results show the effect of the geometric-based adaptivity in preserving the edges, details, highlights, smoothness and color appearance, while removing noise from color images.