露天磷矿数字配矿模型

露天磷矿选矿厂采用合理的配矿方案,对稳定入选磷矿的品位,增加选矿产率,降低生产成本有着重要的意义.为了提高入选磷矿石品位的均匀性和稳定性,提出了针对以入选磷矿品位为目标的从采矿场配矿到精矿仓配矿的整个生产环节的配矿方法.将采场内原矿、选矿厂原矿矿堆和选矿厂精矿仓均定义为矿堆,按照生产实际需求设定其属性.通过设定目标函数,实现使采矿场的开采原矿量最大,配矿方案总的运输距离最小,运输成本最低等目标.同时建立约束条件,使采矿场的开采原矿量要保证选矿厂正常生产,使每一矿堆的品位达到目标要求.最后,采集企业生产实际数据对模型加以验证,证明模型在指导露天磷矿山的生产过程中有重要的实际意义,配矿过程应成为矿山生产组织、管理的一个重要环节.     

基于PCA-LINMAP-FCE的通信系统维修性评价方法

为提高通信系统维修性评价的实用性和可操作性,提出了一种基于 PCA-LINMAP-FCE 的维修性评价方法。在构建简化的维修性评价指标体系的基础上,将 PCA-LINMAP 与模糊综合评判（ FCE）方法相结合,从定量和定性的角度对维修性进行评价。实例仿真分析表明,该方法可操作性强,且有效地降低了评价的主观随意性,使维修设计和作业人员全面掌控通信系统装备维修性的影响因素,能够为科学制定设计方案和维修实施决策方案提供决策信息。     

Economic Benefits of Reservoirs in the Irrigated Agriculture

Abstract

In the Jordan Valley of Jordan, the demand for water and ability to control its location, timing, quality, and quantity are becoming critical. The competition for water between the urban and agricultural sectors is increasing. There is a general trend in Jordan to reduce water allocated for agricultural use. Increasing the price of irrigation water or restricting the planted areas of water consuming crops, such as bananas, has been implemented during the recent growing season. The main objective of this paper is to highlight the impact of optimal allocation of irrigation water by building storage capacity on the economy of Jordan Valley. A linear programming technique is used, and the main results show that for proper management of water storage capacity, the suggested cropping pattern would generate $88.2 million, whereas the actual cropping pattern generated $74.4 million. The optimal water demand schedule is distributed according to the needs of the planted crops, and water demand has been allocated in an efficient way. In addition, appropriate management of storage capacity has solved the problem of water scarcity during the summer months, when peak production takes place. Storage-transfer system between locations played a significant role in reallocating irrigation water through the storage system. This compensates to a high degree in keeping the agricultural production more stable in physical and monetary units.     

Using Similarity Analyses to Scale Out Research Findings Across Andean Watershed Basins

Abstract

Strategic research in agriculture and natural resources carried out by international research centers is deemed a public good and should, sooner or later, be put into the hands of development, governmental and non-governmental organizations. However, this research is usually done at specific pilot sites; there is a greater need to know how representative those sites are in relation to the diversity of contexts in other locations. Such is the case with the Challenge Program on Water and Food (CPWF), a global initiative in water research promoted by the Consultative Group on International Agricultural Research (CGIAR), which is developing and implementing strategic research in nine basins located in the tropics of Africa, Asia and South America. Given that resources are not available to collect data from the whole of the region, pilot sites are needed. It is hoped that research outputs obtained in the selected pilot sites can be the basis for scaling out solutions to similar situations in neighbouring or adjacent areas in same or different basins.

In order to contribute to the scaling-out process, different classification methodologies were applied to determine how specific watershed basins are representative of larger areas. The Andean eco-region served as a case study but the methods can easily be applied in other regions. The spatial diversity of biophysical and social conditions across the Andes requires careful site selection. Two methods, a combination of Weight of Evidence (WofE) and Logistic Regression (LR) methods and Fast Cluster analysis, were used to determine the similarity of selected sites with those excluded. A 1-km study resolution covering most of the Andes eco-region included annual rainfall, elevation, length of growing period, land cover, roads and population density as the key variables. Results showed complementarities between the two methods in presenting a probability surface of similarity across the Andes and a clustering of similar sites inside and outside the pilot basins. The output information forms a strong basis for devising plans to scale out research findings from the pilot basins to the whole region.     

基于近邻估计的年径流预测动态 联系数回归模型

集对分析理论为处理确定、不确定系统提供了新的途径,根据集对分析理论建立起来的预测联系数回归模型可以明显改善回归模型的预测精度。对于预测因子结构具有的动态性,文中将利用近邻估计,通过计算各个预测因子的变异系数,来判断预测因子在某次预测中处于强势或者弱势,进而动态地选择预报功能大的强势因子,消除对预报起负面作用的弱势因子的作用,这样很好地体现了预测因子结构中具有的动态性。基于此建立了基于近邻估计的年径流预测动态联系数回归模型（NNE-DCNR）。结果说明：用NNE-DCNR去预测年径流量,预测精度比常用预测方法有显著提高,在水文水资源的预测中具有推广应用价值     

三峡升船机船厢室底板沉降监测 变形数据分析

三峡升船机是目前世界上规模最大和技术难度最高的升船机,其底板高程为50 m。为监测该底板在施工期间的沉降情况并研究沉降对升船机土建施工、埋件及设备安装的影响,对沉降监测数据及原因进行了分析,建立了变形与影响因素之间的数学模型。研究表明：该底板沉降呈周期性变化且在±2 mm左右,其影响可以忽略不计。     

两种OFDM多普勒估计算法在水声信道中的比较

为了消除多普勒频偏影响,通过水上实验对两种OFDM（Orthogonal Frequency-Division Multiplexing）水声通信多普勒估计算法进行对比。基于拷贝相关时延差估计的多普勒估计算法结构简单、易于实现;基于空载波的算法较复杂,但精度较高。利用两种方法对相同的实验数据进行多普勒估计和补偿,并对其通信误码率进行对比。研究结果表明,在慢变的信道中两者的误码率基本相同,但在快变的信道中基于空载波的算法更稳定。     

节曲线向径以线性速度变化的非圆齿轮研究

提出一种根据给定中心距和传动比范围设计封闭非圆齿轮的方法。在其节曲线形成过程中,引入了节曲线向径变化速度,根据封闭非圆齿轮传动的条件,构建的线性函数,得到节曲线向径以线性速度变化的非圆齿轮;推导新式齿轮的凹凸性、弧长、及压力角公式。通过仿真计算,得到了时间参数1不同的3种非圆齿轮节曲线,比较了3种节曲线及相应传动比函数的变化趋势,总结出传动比函数的对称性随1的变化规律,为新型齿轮的设计选用提供了依据。研究表明：节曲线方程由二次多项式构成的新式齿轮,相对其它非圆齿轮计算简单,构造方便。     

时滞倒立摆的H_∞反馈控制

由于系统的输入滞后不可避免,时滞是影响系统稳定性的因素之一,文中研究具有输入时滞的一级直线倒立摆的H∞控制问题.基于Lyapunov稳定性理论,采用线性矩阵不等式方法得出系统的H∞反馈控制器.文中没有引入自由权矩阵,减小了问题的复杂性.同时考虑系统不确定性.结论可由MATLAB软件直接求解,方便易行.仿真结果证实了方法的有效性.     

基于线性回归分析的视频质量评估方法

文章提出了一种利用线性回归分析方法的无参考视频序列质量评估算法。该算法主要利用帧间编码帧的比特数和该帧与其参考帧的差异两个参数进行线性回归分析来评估视频质量。该方法不需要原始参考视频,算法简单。通过对标准视频序列的仿真实验,该算法可有效评价不同视频的编码质量,使用该质量评估方法测得的失真视频客观质量评分与其主观质量评分有很好的一致性。