Estimation of the shadow prices of pollutants with production/environment inefficiency taken into account: a nonparametric directional distance function approach

This paper deals with the estimation of the shadow prices of pollutants with a nonparametric directional distance function approach, where the inefficiency involved in the production process is taken into account unlike the previous studies. The directional vector, which is critical to the estimation and subject to the criterion for an appropriate efficiency rule proposed here, is calculated by using the annual plans of power plants in terms of production and environment. In the empirical study for Korea's electric power industry during the period of 1990-1995, we find that the average shadow prices of sulfur oxides (SOx), nitrogen oxides (NOx), and total suspended particulates (TSP) are approximately 10% lower than those calculated under the assumption of full efficiency. The methodology we propose and the findings obtained in the empirical study allow us to undertake better decision-making over a broad range of environmental policy issues.     

谈森林防火中的计划火烧

计划火烧是预防森林火灾的一种有效手段,成本低,效果显著。本文详细阐述了计划火烧的意义和作用、计划火烧前的准备工作,并提出了计划火烧的注意事项及实际操作要领。     

紫外光谱结合正交试验设计同时测定水中苯系物

利用正交试验设计,以光谱预处理、特征筛选及多元校正方法为考察因素,每个因素的4种不同方法为水平,确定了水中3种苯系物（苯酚、苯胺及苯甲酸）紫外光谱数据的最佳分析方法,从而建立了其定量校正模型。对于苯酚、苯胺及苯甲酸,其光谱预处理、特征筛选及多元校正分别采用一阶导数+无信息变量消除法（UVE）+偏最小二乘回归（PLSR）,Savitzky-Golay平滑+变量结合种群分析法（VCPA）+PLSR,Savitzky-Golay平滑+移动窗口偏最小二乘法（MWPLS）+PLSR。在独立测试集上3组分的预测误差均方根（RMSEP）分别为0.809 4、0.796 3和0.945 4。水样加标回收实验的回收率为97.79%~103.84%,相对标准偏差（RSD）小于3%。该方法可作为一种同时测定水中苯系物的简便有效方法。     

经济体制转轨下的环境管理模式初探

党的十五大提出发展多种形式的公有制经济,在这种新形势下,环境管理如何转轨,本文进行了探讨和研究。     

Short-term wind speed forecasting based on random forest model combining ensemble empirical mode decomposition and improved harmony search algorithm

ABSTRACT

Wind speed forecasting plays an important role in power grid dispatching management. This article proposes a short-term wind speed forecasting method based on random forest model combining ensemble empirical modal decomposition and improved harmony search algorithm. First, the initial wind speed data set is decomposed into several ensemble empirical mode functions by EEMD, then feature extraction of each sub-modal IMF is performed using fast Fourier transform to solve the cycle of each sub-modal IMF. Next, combining the high-performance parameter optimization ability of the improved harmony search algorithm, two optimal parameters of random forest model, number of decision trees, and number of split features are determined. Finally, the random forest model is used to forecast the processing results of each submodal IMF. The proposed model is applied to the simulation analysis of historical wind data of Chaoyang District, Liaoning Province from April 27, 2015 to May 22, 2015. To illustrate the suitability and superiority of the EEMD-RF-IHS model, three types of models are used for comparison: single models including ANN, SVM, RF; EMD combination models including EMD-ANN, EMD-SVM, EMD-RF; EEMD combination models including EEMD-ANN, EEMD-SVM, EEMD-RF. The analysis results of evaluation indicators show that the proposed model can effectively forecast short-term wind data with high stability and precision, providing a reference for forecasting application in other industry fields.     

The hybrid model of empirical wavelet transform and relevance vector regression for monthly wind speed prediction

ABSTRACT

In order to improve the prediction ability for the monthly wind speed of RVR, the hybrid model of empirical wavelet transform and relevance vector regression (EWT-RVR) is proposed for monthly wind speed prediction in this study. Compared with empirical mode decomposition (EMD), empirical wavelet transform (EWT) can obtain a more consistent decomposition and have a mathematical theory. In order to testify the superiority of EWT-RVR, several traditional RVR models are used to compare with the proposed EWT-RVR method under the situation of the same embedding dimensions. The experimental results show that the proposed EWT-RVR method has a better prediction ability for monthly wind speed than RVR. It can be concluded that the proposed EWT-RVR method for monthly wind speed is effective.     

考虑纵横弯曲的空间杆系有限元计算

在普通刚架有限元计算模型的基础上 ,推导出了考虑空间纵横弯曲有限元的单元刚度矩阵和形函数 ,单元刚度矩阵和形函数考虑了轴力的影响。并以此编制了“kjgj”有限元软件 ,软件考虑了轴力引起的二阶效应。用平面和空间算例进行验证 ,单根杆件只剖分一个单元计算得到的精度可以达到商业软件剖分多个单元达到的精度。     

浅议21世纪数学教育的功能

在我国全面实施素质教育的新形势下，时代赋予了数学教育新的使命。数学教育，一方面具有逻辑严密性、结论可靠性及应用广泛性等科学功能；另一方面又具有陶冶情操、完善个性、培养学生理性思维和创造意识等文化功能。     

岷江流域地表水水质的模糊综合评价

岷江是长江上游的一个重要支流，其水质安全对维持成都平原正常的生产生活起着至关重要的作用。采用模糊综合评价的方法，对岷江流域14个地表水监测断面的水质状况进行了综合评价。结果表明：在14个监测断面中，处于清洁和未污染程度的断面占50％，主要位于岷江流域的上游和下游，其水质状况较好；处于重污染的断面占29％，主要位于岷江流域的中游，水质状况较差。因此，需要加强流域综合治理尤其是对岷江中游的治理，以确保岷江流域的水质安全。     

一维粘性泥石流运动的格子Boltzmann模拟

利用格子Boltzmann方法,对一维粘性泥石流的运动进行了定量化研究和数值模拟,为进一步研究泥石流的运动机制奠定了基础。在模拟一维粘性泥石流运动时,采用了含外力项的格子Boltzmann模型,通过对外力因子、平衡态分布函数的构造,使得宏观统计特性刻画了泥石流运动的非线性特征,成功模拟了泥石流的运动过程,获得了泥石流水深、流速两大要素的时空变化规律,为研究泥石流运动过程提供了一种新手段。