基于DPSA传统分解聚合模型的并联泵站优化   总被引：1，自引：0，他引：1  

仇锦先  程吉林  张仁田  张礼华 《排灌机械》2011,29(6):497-502

针对多决策变量复杂非线性系统优化问题,引入基于DPSA的传统分解聚合模型进行并联泵站叶片全调节优化运行研究.首先将大系统分解为若干个子系统,采用DPSA法对各子系统进行优化;再以各子系统分配水量作为关联变量将各子系统回归方程进行聚合,并由聚合模型确定整个系统的最优解;最后通过关联变量将系统最优解反馈到各子系统,从而得到各子系统相应优化调度过程.通过在江都并联泵站叶片全调节优化中的应用,实现了系统总费用最小时的优化调度过程,确定了各站各时段开机台数及叶片角度的最优组合方案,表明了方法的可行性.同时以单位提水费用为指标,按考虑峰谷电价与不考虑两种情况,分析了江都站不同日均扬程、不同运行负荷下,叶片全调节相对定角恒速的优化运行效果,其中考虑峰谷电价节省费用较多,在满负荷、80%负荷6、0%负荷运行情况下,不同日均扬程单位费用节省率均值分别为7.52%2,2.19%,25.89%.  相似文献   

球形约束变分不等式的光滑化牛顿方法     

李丹衡  张丽  曹定华 《湖南农业大学学报(自然科学版)》2002,29(4)

研究球形约束变分不等式求解的算法 ,提出一种光滑化牛顿方法 ,证明了该方法具有全局收敛性和超线性收敛  相似文献   

H1[0,1]空间中多尺度分析在数值逼近问题中的应用     

马晓剑  范百芝  高晓艳 《东北林业大学学报》2007,35(2):76-77

应用H1[0,1]空间多尺度分析方法解决数值逼近问题,仿真及误差分析结果表明了这一方法对函数逼近的可行性,从而为再生核空间数值逼近提供了一种新的思路。  相似文献   

一类次对称矩阵反问题的最小二乘解     

周富照  张忠志  胡锡炎 《湖南农业大学学报(自然科学版)》2001,28(2)

讨论了一类次对称矩阵反问题的最小二乘解，得到了解的具体表达式；并就这类矩阵的左右逆特征对问题进行了讨论，得到了有解的充分条件及解的通式。  相似文献   

Long-term dynamics and population viability in one of the last populations of the endangered Spiranthes spiralis (Orchidaceae) in the Netherlands     

Hans Jacquemyn  Rein Brys  Jo H. Willems 《Biological conservation》2007,134(1):14-21

During the last decades, most orchid species in much of Western Europe have suffered significant declines and the long-term survival of the remaining populations remains to a large extent uncertain. In particular, populations at range margins may be more prone to extinction than more central populations, as the former tend to be small and isolated, occur in ecologically marginal habitats and have a lower per-capita reproductive rate. In this study, we investigated the long-term dynamics and population viability of a population at the margin of its range of Spiranthes spiralis in the Netherlands. At present, only 2 out of 40 previously known populations persist. Individual plants were monitored for 24 years and their life span, flowering frequency and vegetative growth were determined. Individual plants showed large temporal variation in sexual and vegetative growth among years. The proportion of flowering plants varied from 0 (no plants were flowering) to 100 (all plants were flowering). Vegetative growth, on the other hand, increased when the number of individuals decreased. Dormancy was present, but occurred only in a few individuals. Using a non-structured population viability model, future prospects of this species were assessed. Calculation of extinction probabilities and estimated times to extinction using the diffusion approximation model showed that the species had a relatively high probability (79%) of surviving the next 20 years, whereas the median time to extinction was forty years. However, because 95% confidence intervals of the population growth included 1, we suggest that continued monitoring and additional genetic research are needed to assess the long-term viability of this species.  相似文献   

电子舌检测不同冷藏时间草莓鲜榨汁的品质变化   总被引：2，自引：1，他引：1  

高利萍  王俊  崔绍庆 《农业工程学报》2012,28(23):250-256

为了探讨不同冷藏时间草莓鲜榨汁的品质变化规律,利用电子舌对4℃冷藏草莓鲜榨汁进行逐天的品质检测并进行定性和定量分析。结果显示:通过主成分分析和线性判别分析,电子舌能够很好的反映出不同冷藏时间草莓的鲜榨汁品质的变化趋势,在冷藏最初期草莓鲜榨汁品质下降迅速,其后鲜榨汁品质下降缓慢。采用BP神经网络对草莓鲜榨汁冷藏时间进行预测,训练集的整体识别率达到94.90%,预测集的整体识别率为85.71%。采用偏最小二乘法与多元线性回归对草莓鲜榨汁的主要成分预测可知,偏最小二乘法回归模型的预测效果更好,模型的预测值和实际值的相关系数大于0.9,能够为草莓鲜榨汁品质的预测提供参考。  相似文献   

Dynamic modeling of dry non-woven fabric roller carding and control of web density uniformity. I. Precisely industrial controller design     

Chung-Feng Jeffrey Kuo  Hung-Min Tu  Sung-Yang Wu 《Fibers and Polymers》2009,10(1):102-107

This series of paper discussed the dynamic modeling of non-woven fabric roller carding and the control of web density uniformity. The dynamic system of dry non-woven fabric roller carding was set up to analyze the dynamic model; then in the process of derivation, theoretical exploration and studies were carried out on one carding unit in the system, consisting of cylinder, worker roller, stripper roller. After that, we probed into the relation between rotation angle and angular velocity of carding unit, and analyzed the time-delay of carding unit. With Pade approximation, the time-delay was taken as the simplification of the system model. The above conditions were utilized to derive the transfer function of carding unit and it was extended to the dry non-woven fabric roller carding system combining four of carding units, feed roller, take-in and doffer in series to obtain the transfer function of this whole system. After confirmed by the designed controller, the system was obviously improved in its tracking property. The steady-state error was also eliminated. Meanwhile, with the participation of the controller, this system might produce the maximum overshoot during its transient response. Therefore, this research regulated the reference input according to the designed dominant poles. This combination scheme effectively control the occurrence of the maximum overshoot and make for good system objectives.  相似文献   

一种基于行线性分解的扩展LDPC码     

陈宁夏 《仲恺农业技术学院学报》2008,21(2):25-29

对LDPC码进行打孔和扩展可以实现其码率的改变,一种对原校验矩阵进行线性分解的新方法被用来构造固定码长的扩展LDPC码,从而达到降低码率的效果．它的实现复杂度低,并且增益明显．  相似文献   

分数阶椭圆方程近共振问题解的多重性          下载免费PDF全文

宋树枝  陈尚杰 《西南大学学报(自然科学版)》2018,40(10):95-102

考虑当线性项的参数从右边逼近非主特征值时分数阶椭圆方程的多解性.一方面,通过对泛函在不同特征子空间上的能量水平的估计可构造出一个具有鞍点结构的解;另一方面,当参数充分接近特征值时,结合鞍点定理、Galerkin逼近方法及对近共振对应的特征子空间上能量水平的仔细估算证明第二个解的存在性.  相似文献   

压电微定位系统自适应鲁棒有限时间跟踪控制     

康升征  吴洪涛  杨小龙  李耀  程世 《农业机械学报》2018,49(8):403-410

针对压电微定位系统中存在外界扰动、迟滞等时变不确定、非线性因素影响其定位精度的问题,提出了一种基于函数逼近的自适应鲁棒有限时间控制策略。通过引入具有连续、非奇异,且有限时间收敛特性的终端滑模面,设计了满足压电微定位系统的轨迹跟踪控制律。为了克服该控制器依赖于系统不确定量的边界信息,采用傅里叶级数进行动态逼近,并针对其逼近误差,利用模糊逻辑系统实现在线补偿。最后,应用Lyapunov函数获得傅里叶系数及模糊调节参数的自适应律,并证明了该控制器的有限时间稳定性。仿真分析与实验结果验证了控制策略的鲁棒性与有效性。  相似文献