基于多智能体模型的城市洪涝灾害动态风险评估

围绕城市洪涝灾害过程中对人口动态风险评估的需求,在城市水文水动力模型基础上,提出了基于多智能体模型的城市洪涝灾害动态风险评估方法,分别设置孕灾环境智能体、致灾因子智能体、承灾体智能体的运行规则,并给出多智能体之间的通信机制,以实现城市洪涝灾害过程人口动态风险定量评估。以北京市海淀区清河流域某典型排水分区为例,利用SWMM和LISFLOOD-FP模型,模拟50年一遇设计降雨情景下的洪涝灾害过程,并基于NetLogo模型构建城市洪涝灾害承灾体动态风险评估模型对研究区中的人口动态风险进行了评估。结果表明:50年一遇设计降雨情景下,研究区洪涝风险面积从降雨历时T=4 h的0.608 km^(2)增加到T=30h的2.202 km^(2);常规模拟情景下,研究区低风险人口数持续下降、高风险人口数持续上升,最终低风险人口数稳定占比为75.75%,高风险人口数稳定占比为22.85%;在设置救援避险策略后,研究区低风险人口数先下降后升高,在T=4.5 h时,最低人口数占比为92.30%,而高风险人口数先升高后降低,最高人口数占比为7.07%,最终低风险人口数稳定占比为100%。

The Pay-as-You-Go System of Pension Insurance

The most recent trends in population dynamics have provoked a rigorous debate whether the private or the public pension insurance system should be predominant. The pay-as-you-go system is dominated by the state that guarantees its stability. Private pension insurance provides personal retirement accounts and proper ownership of the accumulated funds, but its sustainability during prolonged market crises and inadequate risk sharing are often questioned. In order to address this issue, this paper makes both an assessment and analysis of the arguments put forward in favor of the preservation of the pay-as-you-go system and a comparison of this system with some of the main characteristics of the private accounts system. This is the basis for seeking the objectively defined role of the pay-as-you-go system in the conditions of the market economy. A couple of conclusions that have been formulated might be of interest for the future improvement of the organization and management of pension insurance.