A Voronoi diagram based population model for social species of wildlife

A population model is presented that accounts for spatial structure within habitat patches. It is designed for social species of wildlife that form social group home ranges that are much smaller than patch size. The model represents social group home ranges by Voronoi regions that tessellate a patch to form a Voronoi diagram. Neighbouring social groups are linked with habitat-confined shortest paths and form a dispersal network. The model simulates population dynamics and makes use of Voronoi diagrams and dispersal networks as a spatial component. It then produces density maps as outputs. These are maps that show predicted animal densities across the patches of a landscape. A construction procedure for the particular Voronoi diagram type used by the model is described. As a test case, the model is run for the squirrel glider (Petaurus norfolcensis), a small arboreal marsupial native to Australia. A time series of density maps are produced that show squirrel glider density changing across a landscape through time.     

矿井通风网络压能图节点分层算法研究

为解决人工绘制矿井通风网络图与压能图工作量繁重的问题,基于对矿井通风网络图与矿井通风压能图的特点与作用的研究,提出了具有通风网络图与压能图部分特点的矿井通风网络压能图的概念及其特点与作用。采用分层算法实现对矿井通风网络压能图中各节点纵向相对位置的确定,为避免巷道两端节点压能值因取整相等时被分到同一层的问题,提出运用最长路径算法对各巷道节点进行第1次分层,再利用各节点的相对压能值进行2次分层的绘制方法。构造以分层算法绘制通风网络压能图的整体框架,为实现矿井通风网络压能图的自动绘制提供了技术支持。     

某市工业源重金属污染源评价

针对某市工业源废水中6种重金属污染物产生现状,利用全国第一次污染源普查云南省数据,用等标污染负荷法计算出各种重金属污染负荷和负荷比,及每个工厂(地区)总的重金属污染负荷和负荷比,对某市工业废水重金属污染源进行评价,利用ARCGIS对该区域重金属产生量进行分析,明确重金属污染源空间分布规律,画出有重金属产生的企业的分布图,各种重金属产生空间分布图,和某市各乡镇的污染负荷等级图。结果表明该地区重金属污染源污染负荷的大小排列顺序是砷>汞>铅>六价铬>铬>镉。各企业的重金属源总污染负荷大小为化工厂>盐化昆明盐矿>盐化厂分厂>蓄电池厂>金属原料加工厂>电源厂>材料厂>废旧电瓶场>铸件厂。某市各镇的重金属污染源污染负荷大小排序为B镇>G镇>D镇>E镇。     

基于鱼骨图的公共安全风险测度与评价

为科学测度我国各地区公共安全风险,改善公共安全状况。基于鱼骨图分析法,建立包括能力和脆弱性指标的公共安全评价指标体系。采用主成分分析法(PCA),结合统计软件SPSS对我国31个省市的公共安全风险进行测度,找出影响公共安全水平的重要因子,计算出各省市公共安全风险的综合评价值,得到不同省市的风险排序,为改善公共安全风险较高地区的安全状况提供了启示。结果表明:我国各地区公共安全的风险水平差异较大且公共安全资源和保障因子是影响公共安全抗风险水平的最重要因子,加大基础设施投资,特别是社会保障类基础设施建设投资,可较好地改善公共安全抗风险状况。     

行李箱携带人群汇流过程的基本图实验研究

行李箱携带者作为公共交通枢纽一种典型的人员类型,研究其对人群运动特征的影响对于公共设施的优化具有重要意义。开展了行李箱携带人群在六种汇流角度下的紧急疏散实验,比较了不同汇流角度对行人运动速度及疏散效率的影响,获取了不同汇流角度和不同测量区域的运动基本图。结果表明：1)在实验设置下,比较不同汇流角度?(出口宽度d=3.00 m)发现,?越小(30°),人群运动速度最大(1.86 m/s)、累计疏散时间最短。随着汇流角度的增大,人群运动速度呈现降低趋势(?=180°时,人群运动速度最小(1.40 m/s)、累计疏散时间最长)。表明汇流角度小的设施,有利于提高行人疏散效率;2)比较不同测量区域的基本图(汇流角度一定)发现,汇流交汇处的人群密度分布要小于离交汇处较远的测量区域;3)比较不同汇流角度的基本图(测量区域一定)发现,汇流交汇处的行人密度与流量主要分布在1.34 m^-2～2.15 m^-2与2.00 (m·s)^-1～3.50 (m·s)^-1之间。并且,在实验观测的密度范围内,行人流量随着人群密度的增加...     

Improved SWAT Model Performance With Time-Dynamic Voronoi Tessellation of Climatic Input Data in Southern Africa1

Andersson, Jafet C.M., Alexander J.B. Zehnder, Bernhard Wehrli, and Hong Yang, 2012. Improved SWAT Model Performance with Time-Dynamic Voronoi Tessellation of Climatic Input Data in Southern Africa. Journal of the American Water Resources Association (JAWRA) 48(3): 480-493. DOI: 10.1111/j.1752-1688.2011.00627.x Abstract: In this study, we compared two approaches to obtain climatic time series for the Soil and Water Assessment Tool (SWAT), namely the conventional centroid method and time-dynamic Voronoi tessellation, and assessed the performance of SWAT in simulating discharge and smallholder maize yields in Southern Africa. Climatic time series were estimated with each method. The Voronoi method utilized all available precipitation and temperature data, but the centroid method used only 14.5 and 82.5%, respectively. After centroid processing, sub-basin time series were on average 42 and 63% incomplete, respectively. After Voronoi processing, all time series were complete. SWAT was fed with each climate dataset. Each model setup was independently calibrated and validated against discharge and maize yield. Similar model performance was obtained with both methods for yield. The root mean squared error during calibration was 0.26 and 0.27 t ha⁻¹ for the centroid and Voronoi methods, respectively (p-value: 0.80). However, daily discharge simulations improved significantly with the Voronoi method. The coefficient of determination increased from 0.24 to 0.39 in the calibration period (p-value: 9.6 × 10⁻¹³) and from 0.41 to 0.48 in the validation period (p-value: 3.1 × 10⁻³). The Voronoi method improved the simulation of the river flow regime. The largest improvements were obtained in data scarce situations, at high spatial and temporal resolution, and where the centroid method performed the worst.     

基于原因-后果分析的机械安全性评估模型研究

阐述建立基于原因-后果分析(CCD)的机械系统安全性评估模型的步骤以及基本事件重要度计算的方法,在此基础上,建立除尘式砂轮机可能发生事故的CCD模型。该模型计算结果显示:首先,除尘式砂轮机的砂轮破裂飞出造成伤人的事故发生概率、严重程度、风险度最高;其次,大量粉尘飞扬造成的后果风险度排在第二,相对较高;最后,防护措施可使该设备事故概率大幅下降。CCD模型可以帮助找到机械系统的相关安全事故类型,并能够衡量出系统"本质安全"能力,从而为设计和安全监察部门进行安全设计及设备管理提供决策依据。     

建筑安全事故中的事件重要性定量分析

为制定建筑安全措施提供理论依据,采用Birnbaum测度描述诱发事故的事件重要度,提出基于二叉判定图(BDD)的建筑安全定量分析方法。在得到安全事故故障树后,该方法执行BDD逻辑运算生成BDD结构,并通过遍历该结构计算各事件的Birnbaum测度值。管理人员可通过量化的重要度数值来分析各事件重要性,确定对工程安全影响最大的一些基本事件,从而制定安全措施来减少事故损失、保证工程质量。BDD结构特点使得该方法便于计算机编程实现,实验数据的对比分析表明BDD方法可正确高效地分析建筑安全事故。     

基于流程图的机场管制塔台风险因素辨识

在对空中交通管制风险模型分析的基础上,确定辨识空管运行过程中风险因素的3条途径。基于运行分析方法建立机场管制塔台航空器放行流程图,结合流程图简表对地面管制准备阶段的风险因素进行分析,提出把鱼刺图与流程图相结合辨识航空器放行过程的风险识别方法。最后,应用上述方法从人-机-环-管方面辨识出机场管制塔台运行过程中的65个风险因素,其中包括40个管制员因素、10个设备因素、9个环境因素和6个管理因素。     

Preparation and Validation of Gridded Emission Inventory of Criteria Air Pollutants and Identification of Emission Hotspots for Megacity Delhi

Delhi is one of the many megacities struggling with punishing levels of pollution from industrial, residential, and transportation sources. Over the years, pollution abatement in Delhi has become an important constituent of state policies. In the past one decade a lot of policies and regulations have been implemented which have had a noticeable effect on pollution levels. In this context, air quality models provide a powerful tool to study the impact of development plans on the expected air pollution levels and thus aid the regulating and planning authorities in decision-making process. In air quality modeling, emissions in the modeling domain at regular interval are one of the most important inputs. From the annual emission data of over a decade (1990–2000), emission inventory is prepared for the megacity Delhi. Four criteria pollutants namely, CO, SO₂, PM, and NO _x are considered and a gridded emission inventory over Delhi has been prepared taking into account land use pattern, population density, traffic density, industrial areas, etc. A top down approach is used for this purpose. Emission isopleths are drawn and annual emission patterns are discussed mainly for the years 1990, 1996 and 2000. Primary and secondary areas of emission hotspots are identified and emission variations discussed during the study period. Validation of estimated values is desired from the available data. There is a direct relationship of pollution levels and emission strength in a given area. Hence, an attempt has been made to validate the emission inventory for all criteria pollutants by analyzing emissions in various sampling zones with the ambient pollution levels. For validation purpose, the geographical region encompassing the study area (Delhi) has been divided into seven emission zones as per the air quality monitoring stations using Voronoi polygon concept. Dispersion modeling is also used for continuous elevated sources to have the contributing emissions at the ground level to facilitate validation. A good correlation between emission estimates and concentration has been found. Correlation coefficient of 0.82, 0.77, 0.58 and 0.68 for CO, SO₂, PM and NO _x respectively shows a reasonably satisfactory performance of the present estimates.