六西格玛与多元线性回归模型在烟丝含水率设计中的应用

在烟草制丝线生产过程中存在参数变异,为稳定生产流程,针对烘丝工序含水率的控制,论文应用六西格玛管理中的DMAIC理论和Minitab统计分析软件,对制丝生产过程数据进行了统计分析,建立了各牌号烟丝的烘丝出口含水率多元线性回归模型。通过引入含水率变化率这一概念,刻画了过程变量与烘丝含水率控制之间的相关性,确定了各牌号烟丝烘丝出口含水率的设计值,以满足各牌号成品烟丝含水率的需要,达到提升成品烟丝含水率合格率的目的。     

基于组合权重的模糊物元模型在机场选址中的应用

机场选址问题涉及到多种影响因素,且不同影响因素之间具有不相容的特点。针对这一问题建立一种基于组合权重的模糊物元分析方法。首先分析影响机场选址的因素,建立机场选址指标体系,并通过组合赋权法确定各指标的权重;随后结合专家意见确定方案对指标的隶属度,从而建立模糊物元模型;最后利用欧式贴近度选出最优方案。结果表明,利用此方法可以得到最优方案,且与验证方法得到的最优方案相一致,证明了其准确性。     

Spillovers in Exchange Rates and the Effects of Global Shocks on Emerging Market Currencies

This paper provides an investigation into the spillover effects of exchange rate returns and volatility for developed and emerging market currencies, using data from 1997 to 2011. The results suggest that spillovers in exchange rate returns have increased steadily over time, in moderate reaction to economic events. In contrast, spillovers in total observed volatility (measured by squared returns) react more strongly to economic events, and this transmission has remained at a relatively high level since the global financial crisis. Furthermore, over the course of time, global shocks would appear to account for a larger proportion of aggregate exchange rate volatility (and the relative importance of domestic shocks has declined). The paper also considers whether the increase in volatility spillover is due to sudden shocks, or whether it is due to changes in the stochastic trend of the underlying volatility process. The results suggests that in most cases, this increase is due to sudden shocks, however, in certain instances country‐specific events may perpetuate changes to the trend of the underlying volatility spillover.     

基于GM和BP网络的年均流量组合预测模型

以岷江紫坪铺测站1937～2004年的实测流量资料为依据,运用灰色拓扑预测方法,在建模过程中将GM(1,1)模型、无偏GM(1,1)模型以及GM(1,1)改进模型与BP神经网络进行优化组合,建立年均流量组合预测模型.本文采用1995～2004年的年均流量资料对模型进行检验,结果表明,预测相对误差值较为合理,可以作为年均流量预测的有效方法.     

基于混合量测的电力系统线性动态状态估计算法

针对当前电力系统中广域测量系统（WAMS）和数据采集与监控（SCADA）系统并存的现状，利用量测变换技术，将SCADA系统下支路功率量测和节点注入功率量测转换为等效的电流相量量测，并与WAMS组成混合量测系统，在此基础上提出了直角坐标系下的线性动态状态估计算法。该算法采用Holt两参数线性指数平滑技术，结合线性定常系统Kalman滤波原理，实现了系统状态的预测和估计。该算法具有常数雅可比矩阵，从而大大减少了动态状态估计的计算时间，保证了动态状态估计的计算精度。通过IEEE 14节点系统的仿真结果，验证了该算法的有效性和优越性。     

Determining loss characteristics of arid zone river waterbodies

Understanding the retention time of water in waterbodies during periods of no surface flow in dryland rivers provides an important context for evaluating the ecological importance of a waterhole to the river system. Time series of water level data were collected from 10 waterbodies spread across three river systems of the Lake Eyre Basin (LBE), Australia. Observed loss rates in the absence of surface flow were compared to modelled evaporation rates in order to determine whether open water evaporation was the main loss process from isolated waterholes and to what extent there is evidence of interaction between the surface water and any shallow groundwater aquifers. The modelled evaporation rates were determined using the Penman combination equation and meteorological data from the closest climate station in the region of the waterbodies. The modelled evaporation data were able to explain only some of the variability in the observed loss data but did highlight periods where other processes (including observation error) need to be invoked. These other possible processes, which include temporary groundwater connection and the effect of heat storage on the evaporation losses, probably contribute as much to the observed data variability as error introduced by the use of regional meteorological data. Assuming evaporation is the dominant process determining water loss in the absence of flow, the persistence of a waterhole is primarily dependent upon its depth when flow ceases. The annual loss shown by most waterbodies lies within the range of the modelled evaporation rate using the Penman combination equation and equates between 1.5 and 2.5 m per annum. The use of water level data in conjunction with the modelled evaporation rates was able to provide important insights into controls on waterbody loss rates and persistence. Copyright © 2007 John Wiley & Sons, Ltd.     

非通航孔桥墩“拦-防”组合防撞方案应用研究

非通航孔桥墩通常结构设计单薄,即便在采用最新防撞技术情况下,也难以将船撞力减少至桥墩自身抗力可承受的范围以内。为解决这一问题,对国内外最新防船撞技术进行了调研分析,提出"拦-防"组合的非通航孔桥墩防撞方法,即触发旋转式拦截网与柔性防撞圈组合的防撞装置。当失控船舶以一定速度靠近大桥桥墩时,首先被桥梁上游的拦截网拦截,在拦截网被拉断过程中,船舶航速将大幅降低。船舶冲出拦网再撞上桥墩时,防撞装置能及早发挥整体作用,化撞击集中力为分布载荷,以及让船尽早滑离而带走尽量多的剩余动能,以达到有效保护桥梁的目的。计算分析研究表明,该装置防撞护效果良好,造价相对低廉,并且易于实施。设计中只要充分结合桥区河床地形,可避免对环境造成负面影响。     

水资源系统分析法在水资源优化配置中的应用

探讨了水资源系统分析法的步骤和数学模型,并以线性规划模型为例建立了水资源优化配置的数学模型,对水资源优化配置提供了一定的依据。     

建设工程标段划分研究

以工程项目由多个子项目组成这一事实为基础,标段划分问题可归纳为把m个子项目组合分配给R个标段这一命题,给出了标段划分的优化模型。论述了工程项目建设成本与标段数之间的关系,不同的标段划分方案其成本不同的主因是组成标段子项目之间的相关关系。指出标段划分应遵循系统性、项目管理、经济性三个基本原则及标段划分实际操作应考虑的问题。     

小浪底水库拦沙初期调控异重流方式初步研究

小浪底水库拦沙运用初期,黄河中游来的峰高、量小、沙多又不够一次调水调沙过程的洪水(在考虑水库前期可调水量之后)入库后一般会形成异重流,且出库沙量大、粒径细,因此水库应及时排出;但如果水沙搭配不好,也会使下游河道发生淤积,且呈现沿程均淤的特点;随着排沙期平均流量的增大,全下游淤积比不断减小,并可以由淤积转为冲刷。针对这类洪水,推荐以下游河道不淤积的关系式进行水沙调控,可以在水库适当补水的情况下实现下游河道少淤甚至不淤的排沙效果。