基于Agent建模的农户土地利用行为模拟研究——以陕西省米脂县孟岔村为例

以Agent强化学习（Reinforcement Learning）模型框架为基础,选择政策、市场、Agent自身及与其它Agent相互作用、土壤肥沃程度等因素作为Agent对环境认识的基础,结合环境反馈值,初步构建了农户土地利用行为决策模型,这对于从微观主体层面揭示土地利用变化的内在机理具有重要意义。论文以陕西省米脂县孟岔村为例,采用农户Agent强化学习模型,模拟了农户土地利用行为,得出以下3个结论：①经过对Agent强化学习模型的检验和验证（按面积统计误差率为5.5%）,认为该模型较适合于微观层面农户土地利用行为的研究;②该模型可定量表达政策、市场、农户自身及与其他农户相互作用等因素对农户土地利用行为决策的影响;③与离散函数的土地利用决策相比,应用连续函数表达农户的土地利用决策比较符合实际农户决策状况（农户最终决策中玉米、蔬菜和其它作物的决策值分别为0.3233、0.4035和0.2732）。同时,在文章的最后还分析了需要进一步研究和探讨的问题：①模型在实现农户决策的空间位置方面取得一定进展,但还存在决策位置失误的问题,函待进一步的研究;②对于影响农户决策的自然因素,探讨定量化表达其对农户影响作用,是下一步研究的重点。     

Application of the AERMOD modeling system for environmental impact assessment of NO2 emissions from a cement complex

We applied the model of American Meteorological Society-Environmental Protection Agency Regulatory Model (AERMOD) as a tool for the analysis of nitrogen dioxide (NO2) emissions from a cement complex as a part of the environmental impact assessment. The dispersion of NO2 from four cement plants within the selected cement complex were investigated both by measurement and AERMOD simulation in dry and wet seasons. Simulated values of NO2 emissions were compared with those obtained during a 7-day continuous measurement campaign at 12 receptors. It was predicted that NO2 concentration peaks were found more within 1 to 5 km, where the measurement and simulation were in good agreement, than at the receptors 5 km further away from the reference point. The Quantile- Quantile plots of NO2 concentrations in dry season were mostly fitted to the middle line compared to those in wet season. This can be attributed to high NO2 wet deposition. The results show that for both the measurement and the simulation using the AERMOD, NO2 concentrations do not exceed the NO2 concentration limit set by the National Ambient Air Quality Standards (NAAQS) of Thailand. This indicates that NO2 emissions from the cement complex have no significant impact on nearby communities. It can be concluded that the AERMOD can provide useful information to identify high pollution impact areas for the EIA guidelines.     

Ozone sensitivity analysis with the MM5-CMAQ modeling system for Shanghai

Ozone has become one of the most important air pollution issues around the world. This article applied both O3/(NOy-NOx) and H2O2/HNO3 indicators to analyze the ozone sensitivity in urban and rural areas of Shanghai, with implementation of the MM5-CMAQ modeling system in July, 2007. The meteorological parameters were obtained by using the MM5 model. A regional emission inventory with spatial and temporal allocation based on the statistical data has been developed to provide input emission data to the MM5-CMAQ modeling system. Results showed that the ozone concentrations in Shanghai show clear regional differences. The ozone concentration in rural areas was much higher than that in the urban area. Two indicators showed that ozone was more sensitive to VOCs in urban areas, while it tended to be NOx sensitive in rural areas of Shanghai.     

虚拟应急物流协同预案编制与流程建模仿真研究

为提高我国应急物流预案运行实施的协同性,提出虚拟应急物流协同预案的概念,分析了虚拟应急物流协同预案的涵义、主要要素及体系结构,论述了虚拟应急物流协同预案编制的基本原则和步骤。在以上研究的基础上,采用着色Petri网理论对虚拟应急物流协同预案流程进行建模,设计了整体流程Petri网模型和各部分流程Petri网模型,并运用仿真软件CPN tools对模型的性能进行了验证,结果表明:模型具有良好的可达性、有界性、活性和公平性。     

Characterization of phosphorus species and modeling for its organic forms in eutrophic shallow lake sediments,North China

Variations of phosphorus （P） and its species in surface sediment of Baiyangdian Lake, a eutrophic shallow lake located in North China, were investigated through combination of field survey and numerical calculation based on cluster analysis. P fractionation was performed by a sequential extraction scheme, categorized as loosely bound P （NH4Cl-P）, reductant soluble P （BD-P）, metallic oxide bound P （NaOH-P）, calcium bound P （HCl-P） and organic P （Org-P）. P concentrations exhibited regional similarities and a total of four sub-areas were identified in which the same rank was HCl-P 〉 Org-P 〉 BD-P ,=NaOH-P 〉NH4Cl-E NH4Cl-P, BD-P and Org-P were found to contribute to P enrichment in overlying water column. Specifically, labile Org-P acted as a potential pool with a greater contribution in aerobic layer compared to anaerobic layer. A hysteresis （lag = 4 months） existed when labile Org-P concentration was negatively correlated with aerobic layer thickness. In view of magnitude of identified P contributors in sub-areas, higher potential of P release was present in Fuhe River and Tang River estuary areas. On the basis of calibration and verification, the mathematical model with parameter settings applied in this study was improved to serve as a tool for limnology management and eutrophic control.     

基于Petri网的进近操作管理模型研究

据世界民航所发生的飞行事故情况看,进近着陆阶段时间短、任务重、环境复杂,是飞行事故多发阶段,占很大的比重,因此进近着陆是保证飞行安全的重要阶段。大多数事故是发生在仪表着陆系统出现故障的非精密进近方式。以机组非精密进近的主要飞行操作为基础建立基于Petri网的事故致因模型,统计分析相关的致因因素,计算相关风险值,通过对数据的分析反馈,形成对相应飞行员的针对性学习及训练的系统性管理模式。     

建筑物作为涉危企业保护层探讨

针对某个固有风险不高的涉危企业甲类库房距离厂外道路路边不满足《建筑设计防火规范[2018版]》要求的案例,通过危险与可操作性分析（HAZOP）和保护层分析（LOPA）,并使用Gexcon公司开发的泄漏及爆炸危害分析软件FLACS进行事故后果模拟,来探讨建筑物作为保护层的可能性。采用HAZOP和LOPA分析库房内戊烷储罐发生火灾爆炸情景,不能确定厂外道路上活动人员和车辆的安全情况,通过FLACS软件进一步进行事故后果模拟,显示库房的防火墙可以作为保护层,火灾爆炸不会伤害到厂外道路上的活动人员和车辆。     

地震应急预案数字化关键技术研究

地震应急预案是地震应急救援的重要组成部分,是对突发地震灾害应急响应和全程管理的操作指南。阐述了地震应急预案在地震应急中的作用和使用现状,指出了数字化地震应急预案的意义。从地震应急预案的形式化描述、数字化建模和地震应急预案数字化系统与其它地震应急技术系统的集成等方面探讨了地震应急预案数字化的关键技术。