A vaccination game based on public health actions and personal decisions

Susceptible-infective-removed (SIR) models are commonly used for representing the spread of contagious diseases. A SIR model can be described in terms of a probabilistic cellular automaton (PCA), where each individual (corresponding to a cell of the PCA lattice) is connected to others by a random network favoring local contacts. Here, this framework is employed for investigating the consequences of applying vaccine against the propagation of a contagious infection, by considering vaccination as a game, in the sense of game theory. In this game, the players are the government and the susceptible newborns. In order to maximize their own payoffs, the government attempts to reduce the costs for combating the epidemic, and the newborns may be vaccinated only when infective individuals are found in their neighborhoods and/or the government promotes an immunization program. As a consequence of these strategies supported by cost-benefit analysis and perceived risk, numerical simulations show that the disease is not fully eliminated and the government implements quasi-periodic vaccination campaigns.     

复杂网络下船舶碰撞风险传播演化分析

为提高海运业的安全水平,针对船舶碰撞风险事件链中的风险传播演化过程,利用事件树分析法(ETA),构造有向赋权复杂网络(CN),分析网络的拓扑结构;改进传统K-壳分解算法的适应性,提出网络节点绝对重要度计算方法;利用易感-感染-恢复(SIR)模型动态模拟风险在CN中的传播演化过程,研究在不同感染率与恢复率组合的情况下,复杂网络中目标节点的动态敏感性。结果表明:大约25%的风险事件在CN中相对不活跃,绝对重要度排前10%的风险事件均与事故直接原因无关;风险事件的敏感度与重要度并不完全保持一致,部分风险事件,即使不采用针对性措施,也难以触发严重后果或碰撞事故;船舶碰撞风险管控工作应认可直接致因的客观存在,重点关注碰撞风险的传播演化过程,在碰撞风险实施管控的过程中应采用差异化管控策略。     

全向辐照电磁环境构建及与BPSK系统的干扰效应研究

目的分析某型通信电台在工作时所处的复杂电磁环境,构建基于混响室原理的全向辐照电磁环境。方法以一个采用标准BPSK信号的数字通信系统为例,研究干扰信号码速、频率偏移量、信干比等参数对系统误码率的影响。结果当干扰信号码速低于期望信号码速时,随着频率偏移量的增加,接收系统误码率也随之减小,且呈现周期性规律;当信干比相同时,在相同的频率偏移下,干扰信号的码速越高,其干扰效果越好;当干扰信号码速高于期望信号码速时,随着干扰信号码速的进一步增大,干扰效果将呈现逐渐降低的趋势。结论该研究在电子装备的复杂电磁环境适应性方面做出了有益探索,为今后的复杂电磁环境适应性理论的深入研究提供了借鉴。     

Instrument tuning for trace analysis of dioxins and furans for the vg 70s/se gas chromatography/mass spectrometry system using electron impact mode

We present the salient characteristics of tuning procedures that have evolved from our 3 years of experience while producing large amounts of data of the highest quality. Our laboratory routinely analyzes 2,3,7,8‐substituted dioxins and furans at parts per quadrillion levels in 50–100 g of human serum samples using the VG 70S/SE stand‐alone gas chromatography/mass spectrometry (GC/MS) system at 10000 resolution (defined by 5% overlap) in the selected ion recording mode. Trace measurement of dioxins and furans in human biological matrices—for example, whole blood, serum, or adipose tissue‐requires reproducible instrument tuning within day as well as among days for quality results. Additionally, instument‐tuning procedures among operators must be reproducible to minimize operator bias because periodically different operators are used. Instrument tuning is highly subjective and argumentive; therefore, to minimize the ambiguity within our laboratory, we have standardized our technique to reproducibly tune the GC/MS system.     

Who should wear mask against airborne infections? Altering the contact network for controlling the spread of contagious diseases

There are several ways of controlling the propagation of a contagious disease. For instance, to reduce the spreading of an airborne infection, individuals can be encouraged to remain in their homes and/or to wear face masks outside their domiciles. However, when a limited amount of masks is available, who should use them: the susceptible subjects, the infective persons or both populations? Here we employ susceptible-infective-recovered (SIR) models described in terms of ordinary differential equations and probabilistic cellular automata in order to investigate how the deletion of links in the random complex network representing the social contacts among individuals affects the dynamics of a contagious disease. The inspiration for this study comes from recent discussions about the impact of measures usually recommended by health public organizations for preventing the propagation of the swine influenza A (H1N1) virus. Our answer to this question can be valid for other eco-epidemiological systems.     

基于复合种群SIR模型的应急防疫物资仓库选址

为提高对疫情的应急响应与控制水平,研究应急防疫物资储备仓库选址方法。首先,综合考虑城市网络中人口及城市间的人流量因素,利用复合种群SIR模型预测应急防疫物资需求量,并以2017年华北地区城市流感数据验证预测准确性;然后,通过栅格化选址区域生成初始解空间,以时效性优先为原则,构建基于P中值模型的大规模区域内储备仓库选址模型,并以加权运输距离最小为目标,设计结合重心法的精英保留遗传算法求解模型;最后,以华北地区防疫物资仓库建设为试验案例,使用真实运输距离数据验证模型和算法的有效性。结果表明:在大规模区域内仓库候选位置未知的情况下,该模型和求解算法能够保证选址方案的合理性和计算敏捷性,在仓库数量有限的条件下满足疫情爆发时的应急防疫物资供应需求。     

On the basic reproduction number and the topological properties of the contact network: An epidemiological study in mainly locally connected cellular automata

We study the spreading of contagious diseases in a population of constant size using susceptible-infective-recovered (SIR) models described in terms of ordinary differential equations (ODEs) and probabilistic cellular automata (PCA). In the PCA model, each individual (represented by a cell in the lattice) is mainly locally connected to others. We investigate how the topological properties of the random network representing contacts among individuals influence the transient behavior and the permanent regime of the epidemiological system described by ODE and PCA. Our main conclusions are: (1) the basic reproduction number (commonly called _R0$R_0$) related to a disease propagation in a population cannot be uniquely determined from some features of transient behavior of the infective group; (2) _R0$R_0$ cannot be associated to a unique combination of clustering coefficient and average shortest path length characterizing the contact network. We discuss how these results can embarrass the specification of control strategies for combating disease propagations.     

印刷电路组件吸湿性尘粒人工模拟试验中关键因素的控制

吸湿性尘粒人工模拟试验(简称湿尘试验)是一种新型的环境试验。通过对试验方法和试验过程中各环节的研究,确定了试验时应把握的关键因素,并最终总结了试验中关键因素控制的方法。这些方法可为湿尘试验的开展提供借鉴作用。