小波支持向量机在大气污染物浓度预测中的应用

用小波分解重构和支持向量机相结合的方法,建立大气污染物浓度预测模型。通过小波分解,将大气污染物浓度序列分解为不同频段的小波系数序列,再对各层的小波系数序列重构到原尺度上。利用相关分析的方法构建出低频小波系数a3和中频小波系数d3的支持向量机模型输入因子为前一天小波系数a3和7个气象因子;高频小波系数d2和d1以前三日的小波系数为输入因子,然后对各小波系数序列采用相应的支持向量机模型进行预测,各小波系数均使用ν-支持向量回归机(ν-SVR)算法和径向基函数,最后通过小波重构合成大气污染物浓度序列的最终预测结果。通过对大气SO2浓度预测实例证明,该大气污染物浓度预测模型具有推广能力较强、预测精度较高、训练速度快、便于建模等优点,具有良好的应用前景。     

Development of marginal emission factors for N losses from agricultural soils with the DNDC–CAPRI meta-model

The article discusses marginal emission factors for N losses from agricultural soils, with rape and wheat as examples, and presents results for EU15 as high-resolution maps and aggregated to Member State level. The results are generated by linking the economic model for the agricultural sector CAPRI (Common Agricultural Policy Regional Impact) with spatial down-scaling, and a statistical meta-model for the bio-physical model DNDC (DeNitrification–DeComposition). For a given agro-economic scenario, CAPRI supplies for each crop the crop share, yield and fertilizer application rate spatially downscaled to clusters of 1 km × 1 km grid cells. The results from CAPRI are processed by a meta-model of DNDC to estimate the local greenhouse gas emissions from the soil. DNDC is a dynamic process-oriented model, which estimates trace gas fluxes and nutrient turnover in agricultural soils. The fit of the regressions is typically very good (0.95R² for the majority of the regressions), and all coefficients are significant at 99% probability. The meta-model allows a seamless integration between the economic and the bio-physical models, offering additional benefit such as the site-specific calibration of the bio-physical model ensuring the match between simulated and observed yield at the grid-level.The meta-model is used to calculate marginal emission factors for a 1 kg ha⁻¹ increase of mineral N and manure fertilizer rates for rape and wheat, at different levels of fertilization. They show that for Western European farming practice, only a small fraction of extra nitrogen fertilizer would go into increased yields: most of it would be emitted to the environment. The largest spatial variability is observed for N₂O emissions. The derivation of marginal emission factors is just one of the many possible uses for the linked regionalized agro-economic and soil chemistry model, which exploits to a large extent both geo-referenced and regionally available statistical information at European scale.     

熵权多目标决策-理想区间法在地下水环境质量综合评价中的应用

通过将多目标决策-理想区间法与熵值法相结合,建立了基于运用熵权来确定权重的多目标决策-理想区间法,应用一种新思路进行地下水环境质量综合评价。结果表明,该方法可以有效地解决地下水环境质量的优劣评价问题,且使评价过程大大简化,评价结果合理。     

突发事件应急决策探讨

随着我国社会经济的发展,突发事件呈现急剧上升的趋势。通过分析总结突发事件应急决策的特点,从多个角度分析比较其与常规决策的差异,总结介绍了应急决策方法,构建了应急决策的流程模型,从突发事件应急决策支持系统的框架模型说明了软件支持、信息支持、辅助决策三个层次需要解决的关键问题,最后总结了应急决策评价的标准和方法等。     

脆弱生态区类型划分及其脆弱特征分析

本文应用聚类分析方法,根据全国各县市耕地面积等26项指标的有关数据,对我国生态区进行了类型划分,还分别以环境资源因子、经济发展水平因子、经济技术替代能力因子、域外支持能力因子以及社会发展水平因子等5类因子为聚类变量,对我国脆弱生态区进行了类型划分,并对脆弱特征进行了分析。     

安全管理决策支持系统及其最新进展

安全管理是企业管理的重要组成部分,是实现安全生产的有力保证.决策支持系统是实现安全管理定性与定量分析有机结合的有效手段.该文结合安全管理,简要阐述了决策支持系统产生的背景、内容和发展趋势.介绍了作者在企业安全管理决策支持系统研制方面的主要结果和进一步工作的构想.     

EXPORT COEFFICIENT MODELING TO ASSESS PHOSPHORUS LOADING IN AN URBAN WATERSHED1

ABSTRACT: An export coefficient modeling approach was used to assess the influence of land use on phosphorus loading to a Southern Ontario stream. A model was constructed for the 1995–1996 water year and calibrated within ± 3 percent of the observed mean concentration of total phosphorus. It was found that runoff from urban areas contributed most to the loading of phosphorus to the stream. When the model was assessed by running it for the 1977–1978 water year, using water quality and land use data collected independently, agreement within ± 7 percent was obtained. The model was then used to forecast the impact of future urban development proposed for the watershed, in terms of phosphorus loading, and to evaluate the reduction in loading resulting from several urban best management practices (BMP). It was determined that phosphorus removal will have to be applied to all the urban runoff from the watershed to appreciably reduce stream phosphorus concentration. Of the BMP designs assessed, an infiltration pond system resulted in the greatest phosphorus load reduction, 50 percent from the 1995–1996 baseline.     

模糊控制理论在煤矿通风安全自动化系统中的应用

由于煤矿通风系统的独特性和复杂性 ,要精确地建立具有时滞及控制对象的数学模型遇到较大的困难 ,因此 ,人们寻求了一些新的解决途径。笔者基于模糊控制理论 ,并提出将其应用于煤矿通风自动化系统中 ,同时采用单片机来实现模糊控制 ,实践证明 ,此法取得良好效果 ;与常规的控制方法相比 ,模糊控制方法具有响应快、控制简单、不需建模等特点 ,适用于矿井通风自动化系统 ;笔者还讨论了调节窗模糊控制系统设计 ,系统的单片机实现及软件编制 ,并进行了实验及实验结果分析 ;最后提出了向自组织方向的深化方案。