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   

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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   

基于经验模态分解削弱多波束残余误差的方法     

赵祥鸿  暴景阳  黄辰虎  黄贤源  陆秀平 《海洋通报》2017,36(6):662-667

针对多波束水深数据中存在的系统性残余误差,提出了基于经验模态分解方法来削弱残余误差的方法:首先利用经验模态分解方法对多波束测深数据作一维分解,将非线性、非平稳的多波束测深数据分解成准线性子波,然后构建水深数据趋势项与残余项,利用中央波束趋势项建立整体数据趋势项,最后加以水深数据残余项还原海底地形,削弱残余误差影响。通过实测多波束测深数据验证方法的有效性。  相似文献   

沙海蜇(Nemopilema nomurai)代谢及分解过程对水环境理化因子及浮游植物影响的研究     

郑珊  孙晓霞 《海洋科学集刊》2017,(52):35-46

从上行控制角度,通过野外采样和围隔培养实验,研究了水母的代谢及分解过程对水体环境中pH、溶解氧、营养盐组成的影响,以及该过程中浮游植物的变化。实验结果表明,沙海蜇在代谢过程中短时间内会大量消耗水体中的溶解氧（dissolved oxygen,DO）,使水体出现低氧和轻度酸化。代谢过程释放出大量营养盐,使水体中的溶解无机氮（dissolved inorganic nitrogen,DIN）浓度在24h内增加为原来的12倍,溶解无机磷（dissolved inorganic phosphorus,DIP）浓度增加了40多倍,进而引起水体中叶绿素a（chlorophyll a,chl a）浓度的增加。沙海蜇的分解过程使水体表现出明显的低氧（缺氧）和酸化现象。沙海蜇生物量越大,分解时间越长,对水体的改变程度越明显,此外,还释放出大量的营养盐并改变原有的营养盐结构,可以刺激甲藻和绿藻的生长,甚至可能引发藻华。  相似文献   

中国夏季高温与北极海冰的联系特征   总被引：1，自引：0，他引：1  

方茸  杨修群 《气象》2009,35(3):81-86

为研究前期以及同时期北极海冰异常对中国夏季高温的影响,根据近50年来中国160个台站的夏季高温资料以及近50年来的北极海冰资料,用SVD诊断分析方法,提取出两场相关最强,协方差最大的三个时次--分别为同期、海冰超前夏季高温9个月和超前13个月.分析研究表明:当北极海冰发生异常时,中国夏季高温异常的响应是滞后的,尤其是滞后9个月、13个月时;北极海冰在1978-1979年突然异常减少,且1979年以后维持海冰偏少的态势;当前期或同时期的北极海冰出现异常增多(减少)时,在中国夏季高温场上的响应以"南区"、"北区"夏季高温异常偏低(偏高),与海冰变化反位相;"中区"夏季高温异常偏高(偏低),与海冰变化同位相.  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   

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   

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   

复杂地表条件反射振幅一致性校正   总被引：6，自引：1，他引：6       下载免费PDF全文

李生杰  施行觉  郑鸿明  王宝善 《地球物理学报》2002,45(6):862-869

通过对地表一致性数学物理模型的前提条件进行剖析,合理地确定了反射振幅一致性校正模型,并依据该模型及其实现条件提出使用共轭梯度方法在时间域对地震记录进行谱分解处理. 通过选择复杂地表条件地区的较为典型的地震记录进行资料处理,结果表明:采用所提出的方法可以有效地校正因复杂地表条件等因素对地震反射振幅而产生的影响. 在复杂地表条件及信噪比较低地区的地震资料处理中,该方法具有处理速度快、抗噪能力强及实际应用效果显著的优点.  相似文献