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1.
对2-D系统理论中尚少有文献涉及的2-D系统有关综合问题进行了初步探讨。主要研究了系统在受到外干扰时用状态反馈消除该在系统实际输出中的影响问题,以及在系统的输入为零时间用状态反馈使系统的输出响应零化的问题。文中得到了这两个问题可解的充分条件,并同时给出了相应的解法和算法。研究结果表明:与1-D的相应问题相比,对系统实施“稳定的2-D综合”具有实质性的困难。这些结果为进一步开发2-D系统的综合设计研  相似文献   

2.
研究一类带不确定输入动态非线性系统的几乎干扰解耦问题 .利用反传设计方法构造了鲁棒状态反馈控制器 ,使得对所有可允许的不确定输入动态 ,闭环系统在零初始状态下从干扰到输出的L2 增益任意小 ,同时在干扰输入恒为零时闭环系统是全局渐近稳定的  相似文献   

3.
研究了目前有共性的几种非线性系统输出反馈H∞干扰衰减方法,证明输出反馈干扰衰减可解的充分条件,给出了状态观测器的具体形式,从实用性和鲁棒性两方面发展了目前非线性系统H∞输出反馈鲁棒控制的结果.文中主要采用微分对策和Lyapunov方法建立非线性系统H∞状态反馈干扰衰减可解的充分条件(Hamilton-Jacobi-Isaacs偏微分方程),并结合复合Lyapunov函数构造输出反馈H∞干扰衰减Hamilton-Jacobi-Isaacs偏微分方程.研究了这一输出反馈律对闭环系统的鲁棒性,并证明了相应闭环系统渐近稳定的充分条件.  相似文献   

4.
通过分析同步码分多址通信中多用户检测器存在的多址干扰和near-far问题,提出了已知信号能量情况下运算量较小的递推反馈检测器(RFD).它利用检测出的强用户信号逐级反馈消除多址干扰和near-far.在未知信号能量情况下,提出利用相关器输出峰值平滑估计信号能量,从而得到具有一定能量跟踪特性的峰值反馈检测器(PFD).运用MonteCarlo模拟证明了RFD和PFD的优越性。  相似文献   

5.
迄今所介绍的协方差控制器只适用于干扰为零均值的高斯白噪声过程,一旦噪声均声不为零或系统存在滞值扰动,系统输出一般将会有偏。该文用状态反馈PI控制器实现了单输入单输出线性随机系统输出无偏无协方差协方差配置,给出了控制器存在的充要条件及其解的一般形式。  相似文献   

6.
反馈线性化方法在锅炉-汽轮机系统控制中的应用   总被引:16,自引:1,他引:15  
为提高锅炉 -汽轮机系统的信号跟踪和抗干扰能力 ,利用输入 -状态反馈线性化和输入 -输出反馈线性化方法分别设计了锅炉 -汽轮机系统的控制律。对于输入 -状态线性化方法由于输入状态为线性关系 ,因此系统可以在较大的范围内正常的工作。对于输入 -输出线性化方法可以验证系统在平衡点邻域零动态稳定 ,然而计算机仿真表明利用输入 -输出反馈线性化设计的控制器由于零动态的稳定范围较小 ,系统只能工作在工作点的邻域。基于以上结果对输入 -状态和输入 -输出反馈线性化方法进行了比较分析。计算机仿真表明利用输入 -状态线性化方法所设计的控制器具有良好的信号跟踪和抗干扰能力  相似文献   

7.
针对一类磁悬浮列车半转向架结构系统的分散输出反馈抗干扰控制问题,通过适当的坐标变换将磁悬浮列车半转向架结构系统的输出跟踪控制问题转化为2个子系统的分散输出反馈抗干扰控制问题,并利用广义比例积分状态观测器技术,分别为2个子系统设计扰动观测器来估计系统测量的状态和干扰;利用扰动观测器的输出信息和输出反馈占优技术为各个子系统设计分散输出反馈抗干扰控制器.理论分析结果表明,在所给出的分散输出反馈抗干扰控制器下,整个闭环系统的状态将收敛到可调的任意小的区域内.仿真结果验证了所给控制算法的有效性.  相似文献   

8.
首先利用微分算法求出系统的相对阶,并证明了对于给定的系统,当选用状态反馈时系统具有微分不变性。然后通过在指定区域内的状态反馈,使系统达到输入-输出解耦,并给出了系统可解的充分必要条件,并用例子进一步验证。  相似文献   

9.
高速光纤通信系统特性研究   总被引:1,自引:0,他引:1  
分析了高速IM/DD光纤通信系统的传输特性,对光通道色散影响和光源相位噪声影响进行了分析,结果表明当光源相位噪声较大时,系统的误码率-平均接收光功率曲线将出现“饱和”现象。对高速光发射机、光接收机技术等进行了深入的研究,通过选择激光器最佳工作状态,设计并完成了2.5Gb/s光发射与光接收模块,并对2.5Gb/s光纤传输实验系统的测试结果进行了分析。实现了109km常规单模光纤的无中继传输,工作波长为1550nm,采用内强度调制/直接检测(IM/DD)方式,误码率为1-10时接收机灵敏度为-31.5dB(以1mW为零电平)。利用EDFA克服光纤的损耗后,无再生中继传输距离达到180km。  相似文献   

10.
利用代数几何方法,研究具有多输入的2-D广义系统Roesser模型的特征多项式系数的任意配置问题.通过引入恰当形式的状态反馈,消除了2-D广义系统的无穷远极点,得到了相应的闭环系统.以代数几何方法为工具,将此闭环系统的特征多项式配置问题转化为判别有理映射是否为到上的,推导出多输入的2.D广义系统Roesser模型由状态反馈几乎任意配置特征多项式系数的充分条件.利用此方法同样可对基于输出反馈的特征多项式配置问题进行研究,并给出了2-D广义系统由输出反馈几乎任意配置特征多项式系数的充分条件,从而丰富和发展了多输入情况下的2-D广义系统特征多项式配置的理论.  相似文献   

11.
Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.  相似文献   

12.
何延凌 《科技信息》2008,(4):258-258
Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women's language from these perspectives: pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women's language, more attention should be paid to language use in social context. What's more, the linguistic phenomena in a speaking community can be understood more thoroughly.  相似文献   

13.
The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3~4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰~ -7.8‰, PDB) and matrix dolomites (-6.6‰~ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084~0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078~0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.  相似文献   

14.
理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。  相似文献   

15.
As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.  相似文献   

16.
AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…  相似文献   

17.
There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.  相似文献   

18.
In the 19th century the society was controlled by men, and women were just appendants of them, they had not any rights and freedom. But Jane was an exception, she showed some characteristics of early feminist. Jane showed her characteristics of feminism in three aspects: rebellion, equality, and independence. These characteristics were helpful to her success, and feminism is the only way out for women of that time.  相似文献   

19.
正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-  相似文献   

20.
We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-  相似文献   

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