具有传感器故障的关联大系统的可靠控制

考虑了一类关联大系统的可靠控制器设计问题，该系统具有常时滞、参数不确定性和传感器故障．其中参数不确定性满足匹配条件，传感器具有部分失效的模型．目的是设计无记忆分散控制器来镇定该系统．通过解线性矩阵不等式获得此控制器，使得当传感器器发生故障时被控系统能够保持渐近稳定．最后通过仿真的例子，验证该状态反馈控制器的可行性．     

参数不确定性模糊大系统的保性能控制:LMI方法

研究了一类具有参数不确定性的关联模糊大系统的保性能控制问题，基于线性矩阵不等式（LMI）方法给出了该不确定性模糊大系统分散状态反馈保性能控制器的设计方案，所设计的分散状态反馈保性能控制器不但使得该不确定性模糊大系统闭环渐近稳定，而且使得其二次型性能指标的上界最小．最后通过一个数值例子说明了所提出方法的有效性．     

宏观经济系统的鲁棒控制

考虑参数不确定性对一类宏观经济系统的影响，研究了宏观经济系统的鲁棒控制问题，给出系统的鲁棒控制律以及经济系统鲁棒稳定的条件,鲁棒控制律保证了宏观经济系统稳定的运行，同时可以使国民产总值在短时间内跟踪总需求,通过仿真验证了该算法的有效性．     

线性不确定大系统的分散变结构控制

本研究了具有参数摄动、关联影响和外界干扰等不确定因素影响的线性大系统的分散控制问题。在假设系统不确定性有界且满足一定匹配条件的前提下,给出了系统的一种分散变结构控制算法,实现了大系统的全局渐近稳定。该控制律设计简单,并保证了闭环系统较好的动态性能和较强的鲁棒性。     

一种分散鲁棒自适应控制器的设计方法

基于李雅普诺夫函数法,提出了一种适用于不确定性线性大系统的分散鲁棒稳定控制方法．系统的不确定性因素包括系统参数摄动、关联变化以及外界干扰．由于实际大系统的不确定因素复杂且系统关联变化很难描述,因而在控制律中又引入了对设计参数的自适应算法,大大简化了控制器的设计和实现．所提出的控制律可以保证系统在不确定性干扰和关联变化的情况下全局稳定,同时自适应算法使参数收敛．仿真结果表明了该控制方法的有效性     

一类不确定组合广义大系统的稳定性

一类不确定组合广义大系统所含有的不确定性是时不变未知但范数有界的，对所有容许的不确定性，寻找通过子系统特征，使得该不确定组合广义大系统都是正则的、脉冲自由且稳定的条件。应用线性矩阵不等式方法，给出了完全用子系统特征描述的该类不确定组合广义大系统稳定性的充分条件；作为主要结果的特例，给出了不合不确定项的组合广义大系统的用子系统特征描述的稳定性条件。最后用数值例子说明该方法的应用。     

一类不确定广义大系统的鲁棒镇定

考虑了一类参数不确定广义互联大系统的分散鲁棒镇定问题,所考虑的不确定参数满足范数有界条件,利用LMI方法,给出了保证闭环系统鲁棒稳定的充分条件,最后用数值算例说明该方法简单有效．     

不确定时滞关联系统的鲁棒稳定性分析

本文针对具有强结构不确定性的时滞关联大系统,通过构造适当的Lyapunov函数,并利用M矩阵的性质,给出了系统时滞无关的鲁棒稳定充分条件。并通过一个算验证例了所得结果。     

基于状态观测器的不确定组合大系统的分散变结构控制

基于状态观测器，给出了具有参数摄动、关联影响和外界干扰等不确定因素影响的线性组合大系统的一种分散变结构控制器的设计方法，该控制器设计简单并能保证闭环大系统的全局渐近稳定．     

一类多平衡态非线性系统的动态输出反馈鲁棒容错控制

针对一类多平衡态非线性系统,考虑系统具有范数有界时变参数不确定性,存在执行器故障时的绝对稳定控制问题.对于Lur’e型多平衡态非线性系统,基于将Leonov的频域判据转化为H∞次优问题,考虑系统具有范数有界时变参数不确定性,且系统的执行器出现故障时,采用动态输出反馈控制,给出系统鲁棒容错控制器存在性问题的判据,进一步给出了基于LM I(线性矩阵不等式)的鲁棒控制器的设计方法.仿真表明了该方法的有效性.     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

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.     

An Index mechanism for multi-scale view in spatial databases

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.     

A computer generator for randomly layered structures

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

海南岛地体及其毗邻陆缘晚中生代—新生代古地磁研究和构造演化

本文叙述了对海南岛及其毗邻大陆边缘白垩纪到第四纪地层岩石进行古地磁研究的全部工作过程。通过分析岩石中剩余磁矢量的磁偏角及磁倾角的变化,提出海南岛白垩纪以来经历的构造演化模式如下:早期伴随顺时针旋转而向南迁移,后期伴随逆时针转动并向北运移。联系该地区及邻区的地质、地球物理资料,对海南岛上述的构造地体运动提出以下认识:北部湾内早期有一拉张作用,主要是该作用使湾内地壳显著伸长减薄,形成北部湾盆地。从而导致了海南岛的早期构造运动,而海南岛后期的构造运动则主要是受南海海底扩张的影响。海南地体运动规律的阐明对于了解北部湾油气盆地的形成演化有重要的理论和实际意义。     

Exciton Seebeck in Molecular Systems

Various applications relevant to the exciton dynamics,such as the organic solar cell,the large-area organic light-emitting diodes and the thermoelectricity,are operating under temperature gradient.The potential abnormal behavior of the exicton dynamics driven by the temperature difference may affect the efficiency and performance of the corresponding devices.In the above situations,the exciton dynamics under temperature difference is mixed with     

Achieving Unusual States of Matter Under High Pressure

The elongation method,originally proposed by Imamura was further developed for many years in our group.As a method towards O(N)with high efficiency and high accuracy for any dimensional systems.This treatment designed for one-dimensional(ID)polymers is now available for three-dimensional(3D)systems,but geometry optimization is now possible only for 1D-systems.As an approach toward post-Hartree-Fock,it was also extended to     

《Chinese Science Bulletin》SUBJECT INDEX TO VOLUME 59(2014)

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An on-line scaling method for improving scalability of a database cluster

The explosive growth of the Internet and database applications has driven database to be more scalable and available, and able to support on-line scaling without interrupting service. To support more client's queries without downtime and degrading the response time, more nodes have to be scaled up while the database is running. This paper presents the overview of scalable and available database that satisfies the above characteristics. And we propose a novel on-line scaling method. Our method improves the existing on-line scaling method for fast response time and higher throughputs. Our proposed method reduces unnecessary network use, i.e. , we decrease the number of data copy by reusing the backup data. Also, our on-line scaling operation can be processed parallel by selecting adequate nodes as new node. Our performance study shows that our method results in significant reduction in data copy time.     

An improved R-tree based on childnode''s probability

R-Tree is a good structure for spatial searching. But in this indexing structure,either the sequence of nodes in the same level or sequence of traveling these nodes when queries are made is random. Since the possibility that the object appears in different MBR which have the same parents node is different, if we make the subnode who has the most possibility be traveled first, the time cost will be decreased in most of the cases. In some case, the possibility of a point belong to a rectangle will shows direct proportion with the size of the rectangle. But this conclusion is based on an assumption that the objects are symmetrically distributing in the area and this assumption is not always coming into existence. Now we found a more direct parameter to scale the possibility and made a little change on the structure of R-tree, to increase the possibility of founding the satisfying answer in the front sub trees. We names this structure probability based arranged R-tree (PBAR-tree).     

Wuhan University Journal of Natural Sciences TOTAL CONTENTS

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