H∞ loop-shaping controller design for a grid-connected single-phase photovoltaic system

This paper presents a H_∞ loop-shaping controller for controlling dc-link voltage by regulating the switching signal of the inverter associated with a grid-connected single-phase photovoltaic system. To facilitate a robust control design, state-space realisation of the system model is made with uncertainties represented by linear fractional transformation. The controller is achieved through H_∞ synthesis followed by obtaining desired loop shapes through the choice of the proper weighting functions. The controller order is reduced by Henkel-norm method for facilitating its practical implementation. Controller performance is evaluated through carrying out simulations on MATLAB/Simulink platform under standard and changing atmospheric conditions, and fault condition.     

不同类型压力对飞行员安全绩效的影响规律研究

为探究各类型压力对飞行员安全绩效的影响规律，为飞行员日常工作管理提供依据，选取某航空公司200名飞行员进行压力测试，并调取其近6 a的飞机品质(QAR)数据，通过相关性分析和线性回归分析将飞行员压力数据与其QAR数据进行对比分析，探究飞行员压力对飞行安全绩效的影响规律。研究结果表明:工作负荷压力、家庭压力、人际关系压力和组织管理压力会显著负向影响飞行员安全绩效；角色压力和专业发展压力会显著正向影响飞行员安全绩效。     

示踪技术用于气体泄漏扩散模拟的多元线性回归分析

采用江苏工业学院油气储运安全综合实验模型平台,利用示踪技术(以CO2为示踪剂),模拟了有害气体瞬时泄漏扩散的整个过程.并结合多元线性回归分析的基本方法,定量分析了气体泄漏扩散过程,建立了多元线性回归模型,初步确定了泄漏气体浓度与相关物理量的变化关系,在此基础上得到了2个定量评价指标:确定性系数R=0.991,相关系数r=0.995.研究表明,在实验室建立的试验模型能较好地反映现实情况,模型仿真度较高,数据拟合效果较好.研究可为评价模型的相似性提供理论参考,对有害气体泄漏扩散事故应急救援、实施有效的现场控制,具有一定的科学参考价值.     

新安江流域土地利用结构对水质的影响

以新安江上游流域为研究区域,用该流域2010年5月TM遥感影像图作为底图,通过实地野外调查获取了新安江流域的土地利用图.运用ArcGIS的水文、空间分析功能,将流域划分为8个子流域,并分析各子流域的土地利用结构.根据2010年1～12月的水质监测数据,分析TN、TP、高锰酸盐指数、NH4+-N、粪大肠菌群的时空变化特征,以及与土地利用结构之间的定量关系.结果表明,TN和NH4+-N有明显的时间变化特征,为枯时期>丰水期>平水期,而其他几种指标没有明显的时间变化.在空间上,整体上呈现出渔梁、浦口污染最为严重.流域内土地利用结构与水质之间的相关关系表现为:耕地、水体、建筑用地起源作用,林地、草地起汇作用.在年度上看,耕地对TN、NH4+-N、高锰酸盐指数影响最大,草地对TP影响最大;不同水期上,枯水期和丰水期,对各指标影响最大的土地利用类型为耕地,在平水期,对TN、TP、粪大肠菌群影响最大的土地利用类型分别为耕地、草地、林地.     

Multi-objective transportation route optimization for hazardous materials based on GIS

Safety and security are of paramount importance, it is important to optimize and improve the routes of trucks that carry hazardous materials. In this study, we not only ensure the risk in the network, but also consider the transportation cost and the factors such as buildings and emergency facilities around the routes. The Geographic Information System (GIS) is used to quantify the factors on each section in the network. We present an epsilon constrained multi-objective mixed-integer linear programming optimization model to find the robust and stable transportation optimization solutions. At the end, we complete a case analysis of the proposed methodology to determine the motorway segments in Jiangsu province, China and test the above algorithm on the network, which has 144 nodes and 388 sections. The results we get show that the factors of buildings play a very important role in the model, and the multi-objective mixed-integer linear optimization model is reasonable and performs good quality.     

基于CALPUFF模型的漳州市大气环境容量研究

研究表明：CALPUFF模式是运用于广域的大气扩散模型,在区域范围较大的复杂地形条件下的应用具有突出的优势.利用CALPUFF大气扩散模型模拟漳州市2009年气象场和污染物浓度场,采用监测值对模拟结果进行验证表明模型的适用性;基于现状污染源,建立大气污染物传递系数矩阵,结合线性优化法测算了不同环境空气质量标准下漳州市大气环境容量.     

Evaluation of accuracy of linear regression models in predicting urban stormwater discharge characteristics

Stormwater runoff has been identified as a source of pollution for the environment, especially for receiving waters. In order to quantify and manage the impacts of stormwater runoff on the environment, predictive models and mathematical models have been developed. Predictive tools such as regression models have been widely used to predict stormwater discharge characteristics. Storm event characteristics, such as antecedent dry days （ADD）, have been related to response variables, such as pollutant loads and concentrations. However it has been a controversial issue among many studies to consider ADD as an important variable in predicting stormwater discharge characteristics. In this study, we examined the accuracy of general linear regression models in predicting discharge characteristics of roadway runoff. A total of 17 storm events were monitored in two highway segments, located in Gwangju, Korea. Data from the monitoring were used to calibrate United States Environmental Protection Agency＇s Storm Water Management Model （SWMM）. The calibrated SWMM was simulated for 55 storm events, and the results of total suspended solid （TSS） discharge loads and event mean concentrations （EMC） were extracted. From these data, linear regression models were developed. R2 and p-values of the regression of ADD for both TSS loads and EMCs were investigated. Results showed that pollutant loads were better predicted than pollutant EMC in the multiple regression models. Regression may not provide the true effect of site-specific characteristics, due to uncertainty in the data.     

高效液相色谱-三重四级杆/复合线性离子阱质谱法测定饮用水中22种邻苯二甲酸酯

建立了一种同时测定饮用水中22种邻苯二甲酸酯(PAEs)的高效液相色谱-三重四级杆/复合线性离子阱质谱方法:饮用水样品经针头过滤器过滤,选用Biphenyl液相色谱柱进行分离,以含0.1%甲酸的水溶液和含0.1%甲酸的甲醇溶液为流动相,电离模式为电喷雾正离子,选用多反应监测触发增强子离子扫描模式进行检测。结果表明,22种PAEs的灵敏度良好,定量限为0.001～0.1 μg/L。配制浓度为0.1～100.0 μg/L的混标溶液进行进样分析,分析结果显示,22种PAEs在该范围内的线性关系良好,相关系数均大于0.995,方法的平均回收率为82.9%～108.9%,相对标准偏差为0.9%～11.2%。同时,使用增强子离子扫描谱图进行搜库匹配,定性准确性高。该方法适用于饮用水中PAEs的检测。     

Shifting elasmobranch community assemblage at Cocos Island—an isolated marine protected area

Fishing pressure has increased the extinction risk of many elasmobranch (shark and ray) species. Although many countries have established no‐take marine reserves, a paucity of monitoring data means it is still unclear if reserves are effectively protecting these species. We examined data collected by a small group of divers over the past 21 years at one of the world's oldest marine protected areas (MPAs), Cocos Island National Park, Costa Rica. We used mixed effects models to determine trends in relative abundance, or probability of occurrence, of 12 monitored elasmobranch species while accounting for variation among observers and from abiotic factors. Eight of 12 species declined significantly over the past 2 decades. We documented decreases in relative abundance for 6 species, including the iconic scalloped hammerhead shark (Sphyrna lewini) (?45%), whitetip reef shark (Triaenodon obesus) (?77%), mobula ray (Mobula spp.) (?78%), and manta ray (Manta birostris) (?89%), and decreases in the probability of occurrence for 2 other species. Several of these species have small home ranges and should be better protected by an MPA, which underscores the notion that declines of marine megafauna will continue unabated in MPAs unless there is adequate enforcement effort to control fishing. In addition, probability of occurrence at Cocos Island of tiger (Galeocerdo cuvier), Galapagos (Carcharhinus galapagensis), blacktip (Carcharhinus limbatus), and whale (Rhincodon typus) sharks increased significantly. The effectiveness of MPAs cannot be evaluated by examining single species because population responses can vary depending on life history traits and vulnerability to fishing pressure.     

Socio‐economic benefits from protected areas in southeastern Australia

International case studies of protected area performance increasingly report that conservation and socio‐economic outcomes are interdependent. Effective conservation requires support and cooperation from local governments and communities, which in turn requires that protected areas contribute to the economic well‐being of the communities in which they are sited. Despite increasing recognition of their importance, robust studies that document the socio‐economic impacts of protected areas are rare, especially in the developed world context. We proposed 3 potential pathways through which protected areas might benefit local communities in the developed world: the improved local housing value, local business stimulus, and increased local funding pathways. We examined these pathways by undertaking a statistical longitudinal analysis of 110 regional and rural communities covering an area of approximately 600,000 km² in southeastern Australia. We compared trends in 10 socio‐economic indicators describing employment, income, housing, business development and local government revenue from 2000 to 2010. New protected areas acquisitions led to an increased number of new dwelling approvals and associated developer contributions, increased local business numbers, and increased local government revenue from user‐pays services and grants. Longer‐term effects of established protected areas included increased local council revenue from a variety of sources. Our findings provide support for each of our 3 proposed benefit pathways and contribute new insights into the cycling of benefits from protected areas through the economy over time. The business and legislative models in our study are typical of those operating in many other developed countries; thus, the benefit pathways reported in our study are likely to be generalizable. By identifying and communicating socio‐economic benefits from terrestrial protected areas in a developed world context, our findings represent an important step in securing local support and ongoing high‐level protection for key components of the world's biodiversity.