On the study of control effectiveness and computational efficiency of reduced Saint-Venant model in model predictive control of open channel flow     

M. Xu  P.J. van OverloopN.C. van de Giesen 《Advances in water resources》2011,34(2):282-290

Model predictive control (MPC) of open channel flow is becoming an important tool in water management. The complexity of the prediction model has a large influence on the MPC application in terms of control effectiveness and computational efficiency. The Saint-Venant equations, called SV model in this paper, and the Integrator Delay (ID) model are either accurate but computationally costly, or simple but restricted to allowed flow changes. In this paper, a reduced Saint-Venant (RSV) model is developed through a model reduction technique, Proper Orthogonal Decomposition (POD), on the SV equations. The RSV model keeps the main flow dynamics and functions over a large flow range but is easier to implement in MPC. In the test case of a modeled canal reach, the number of states and disturbances in the RSV model is about 45 and 16 times less than the SV model, respectively. The computational time of MPC with the RSV model is significantly reduced, while the controller remains effective. Thus, the RSV model is a promising means to balance the control effectiveness and computational efficiency.  相似文献   

Regional inequality and polarization in the context of concurrent extreme weather and economic shocks     

《Applied geography (Sevenoaks, England)》2015

This study examines how extreme weather influences regional inequality and polarization within Mozambique in the context of on-going economic shocks. Utilizing satellite-based estimates of rainfall spatially analyzed within a GIS, we establish a 16-year rainfall climatology and calculate monthly rainfall anomalies for 665 villages. We approximate storm-total rainfall from all tropical cyclones entering the Mozambique Channel, as well as the extent of damaging winds for those making landfall, between 2005 and 2008. We group villages according to tropical cyclone impacts and use hierarchical cluster analysis to group the remaining villages according to shared patterns of monthly rainfall anomalies. Using economic data from the 2005 and 2008 National Agricultural Surveys of Mozambique, we relate weather patterns associated with near normal rainfall, tropical cyclones, flooding, and drought to changes in inequality and polarization by conducting decomposition analyses of the Gini index and Duclos-Esteban-Ray (DER) polarization index. Our findings mainly correspond to the generally accepted view that weather shocks exacerbate existing income and power disparities within societies. However, in some cases we find evidence that inequality and polarization can decline in the aftermath of an extreme event, and increase even where the weather is relatively good. By identifying varying effects of extreme events on inequality and polarization at subnational level, our study enables a more detailed understanding of weather-related effects on socio-economic outcomes in rural societies rapidly integrating into the global economy.  相似文献   

基于MTM-SVD方法的西南地区降水季节内振荡特征分析     

王春学  马振峰  邓彪  王佳津 《高原气象》2015,34(1):59-69

利用1981-2010年中国西南地区气象站点逐日降水资料以及NCEP/NCAR逐日再分析资料,使用MTM-SVD方法分析了西南地区降水的季节内振荡特征,结果表明:西南地区降水存在显著的14.4候(70天左右)振荡周期,该季节内振荡在1985年前后最强,在整个研究时段内夏季更明显。典型循环重建表明,西南地区降水的季节内振荡整体上有一个从南向北的推进过程,对OLR的分析表明,南海—西太平洋地区和孟加拉湾地区是影响西南地区降水的两个关键区。在季节内振荡尺度上影响西南地区降水的OLR异常信号首先出现在爪哇岛附近,逐渐向东传播到马鲁古群岛地区,然后北跳传播到北半球的南海—西太平洋地区和孟加拉湾地区,最后两者先后向北推进影响西南地区降水。  相似文献   

STUDY ON THE QUASI-FOUR YEAR OSCILLATION OF AIR-SEA INTERACTION          下载免费PDF全文

朱艳峰  陈隆勋 《Acta Meteorologica Sinica》2000,(3)

Complex Singular Value Decomposition(CSVD)analysis technique was applied to study theQuasi Four year Oscillation(QFO)of air sea interaction and its coupled pattern evolution duringdifferent phases.Results show that:(1)CSVD method can better reveal phase relation betweentwo physical fields:(2)Not only northerly anomalies from Northern Hemisphere but alsosoutherly anomalies from Southern Hemisphere contribute to EI Nino.They converge in westernequatorial Pacific,leading to outburst of strong equatorial westerly anomalies,and result in strongEl Nino event onset:(3)An abnormal subtropical anticyclone circulation appears overnorthwestern Pacific while El Nino developing.It favors transitions from the warm SST(EINino)to the cold SST(La Nina),just as the tropical westerly anomalies produced by abnormalcyclone during a decaying La Nina.which encourage the development of El Nino:(4)Thewesterly anomalies in equatorial Pacific are mainly induced by eastward abnormal subtropicalcyclone pairs,which are located in north and south Pacific respectively,and are not the eastwardwesterly anomalies from equatorial Indian Ocean.  相似文献   

STUDY ON THE QUASI-FOUR YEAR OSCILLATION OF AIR-SEA INTERACTION^*          下载免费PDF全文

ZHU Yanfeng  CHEN Longxun 《Acta Meteorologica Sinica》2000,14(3):293-306

Complex Singular Value Decomposition(CSVD)analysis technique was applied to study the Quasi Four year Oscillation(QFO)of air sea interaction and its coupled pattern evolution during different phases.Results show that:(1)CSVD method can better reveal phase relation between two physical fields:(2)Not only northerly anomalies from Northern Hemisphere but also southerly anomalies from Southern Hemisphere contribute to EI Nino.They converge in western equatorial Pacific,leading to outburst of strong equatorial westerly anomalies,and result in strong El Nino event onset:(3)An abnormal subtropical anticyclone circulation appears over northwestern Pacific while El Nino developing.It favors transitions from the warm SST(EINino)to the cold SST(La Nina),just as the tropical westerly anomalies produced by abnormal cyclone during a decaying La Nina.which encourage the development of El Nino:(4)The westerly anomalies in equatorial Pacific are mainly induced by eastward abnormal subtropical cyclone pairs,which are located in north and south Pacific respectively,and are not the eastward westerly anomalies from equatorial Indian Ocean.  相似文献   

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鲁铁定  陶本藻  周世健 《大地测量与地球动力学》2007,27(5):63-67

??????????????(SVD,Singular Value Decomposition)????????????????????????????M-P??????????????????ó????????????????????????M-P??????;??????????????????????????С??????С?????????????????????????????????????????????????????????;?????????С??????С??????????????????????????????????????δ???????С??????С?????;????????????????????????????????????????????????Ч???  相似文献   

基于经验模态分解的高分辨率影像融合   总被引：9，自引：0，他引：9  

王坚  张继贤  刘正军  高祥 《遥感学报》2007,11(1):55-61

文章提出基于经验模态分解（Emp iricalMode Decomposition,EMD）的特征层影像融合模型。对多光谱波段影像进行IHS变换获得强度影像,采用行列分解实现一维经验模态分解的二维拓展,并用于分离高分辨波段影像与强度影像的细节特征信息,对高分辨率波段影像的高频与强度影像波段的低频进行重构获得融合后的强度影像,再通过IHS反变换获得融合影像。文章介绍了经验模态分解的基本原理,定义了经验模态分解的多尺度分解与合成结构,提出融合模型的技术路线。选择UICKB IRD影像的全色波段与多光谱波段进行融合实验,根据典型行（列）的EMD分析,确定经验模量的取舍尺度,按提出的融合路线获得融合影像,并与小波融合,IHS融合,Brovey融合模型获得的影像进行视觉及量化比较。选择信息熵、标准差指标对融合影像的空间细节信息进行评价,同时选择平均灰度值、相关系数、偏差指数评价融合影像的光谱扭曲程度,结果表明本融合模型最优。  相似文献   

Thermal behaviour of pyrope at 1000 and 1100 °C: mechanism of Fe<Superscript>2+</Superscript> oxidation and decomposition model     

R.?ZborilEmail author  M.?Mashlan  K.?Barcova  J.?Walla  E.?Ferrow  P.?Martinec 《Physics and Chemistry of Minerals》2003,30(10):620-627

The mechanism of thermally induced oxidation of Fe²⁺ from natural pyrope has been studied at 1000 and 1100 °C using ⁵⁷Fe Mössbauer spectroscopy in conjunction with XRD, XRF, AFM, QELS, TG, DTA and electron microprobe analyses. At 1000 °C, the non-destructive oxidation of Fe²⁺ in air includes the partial stabilization of Fe³⁺ in the dodecahedral 24c position of the garnet structure and the simultaneous formation of hematite particles (15–20 nm). The incorporation of the magnesium ions to the hematite structure results in the suppression of the Morin transition temperature to below 20 K. The general garnet structure is preserved during the redox process at 1000 °C, in accordance with XRD and DTA data. At 1100 °C, however, oxidative conversion of pyrope to the mixed magnesium aluminium iron oxide, Fe-orthoenstatite and cristoballite was observed. During this destructive decomposition, Fe²⁺ is predominantly oxidized and incorporated into the spinel structure of Mg(Al,Fe)₂O₄ and partially stabilized in the structure of orthoenstatite, (Mg,Fe)SiO₃. The combination of XRD and Mössbauer data suggest the definite reaction mechanism prevailing, including the refinement of the chemical composition and quantification of the reaction products. The reaction mechanism indicates that the respective distribution of Fe²⁺and Fe³⁺ to the enstatite and spinel structures is determined by the total content of Fe²⁺ in pyrope.  相似文献   

造山带及变质岩区构造岩片多重分解综合复原法   总被引：1，自引：1，他引：0  

严城民  张启跃 《云南地质》2001,20(3):314-322

通过1：25中甸县幅、贡山县幅区调实践,初步认为：造山带及变质岩区填图,可采用“构造岩片多重人解综合复原法”。研究途径和技术路线为：以当代先进的构造变形、变质作用理论为指导,从划分构造岩片入手,对构造岩片进行多重分解。在分别查明各构造岩片的物质组成、生成时期、形成环境及原始位态的基础上,进行构造岩片的逐级组合与综合复原,揭示造山带的形成机制及大地构造演化历程。  相似文献   

Mesquite (Prosopis juliflora (Sw.) DC.), huisache (Acacia farnesiana (L.) Willd.) and catclaw (Mimosa biuncifera Benth.) and their effect on dynamics of carbon and nitrogen in soils of the semi-arid highlands of Durango Mexico     

G. Herrera-Arreola  Y. Herrera  B.G. Reyes-Reyes  L. Dendooven   《Journal of Arid Environments》2007,69(4):583-598

In the northern semiarid and arid part of Mexico, mesquite (Prosopis juliflora (SW.) DC.), huisache (Acacia farnesiana (L.) Willd.) and catclaw (Mimosa biuncifera Benth.), N₂-fixing trees or shrubs, dominate the landscape. It is unknown, however, how much the leaves of those shrubs contribute to dynamics of carbon (C) and nitrogen (N) in soil. We investigated this by adding leaves of each species to soil sampled under the canopy of mesquite, huisache, and catclaw and outside their canopy while monitoring production of carbon dioxide (CO₂), and dynamics of inorganic N (ammonium (NH₄⁺) and nitrate (NO₃⁻)) in an aerobic incubation. The (hemi)cellulose and N content of the catclaw leaves was lower and the lignin and polyphenol content was larger than in the mesquite and huisache leaves. If we considered no priming effect, then 41% of the C added with catclaw leaves, 47% with huisache leaves and 49% with mesquite leaves mineralized within 42 days. The addition of the leaves had little or no effect on N mineralized, and only 6% of organic N of the mesquite leaves was mineralized. It was found that catclaw, huisache and mesquite have a positive effect on the arid and semi-arid ecosystems as they increased soil organic matter and soil N content.  相似文献