关于小波空间的框架

无论是信号处理，还是图像处理，首先要把模拟信号转换成数字信号，如何转换就涉及到采样问题，而框架理论是研究非均匀采样问题的一个重要工具．文章讨论若{2j/2ψ（2^jx-λn），n∈Z}是Wj的框架，对与另一采样集{an，n∈Z}满足什么样的条件，使得{2^j/2ψ（2^jx-an）,n∈Z}也是Wj的框架。     

具有矩阵伸缩的正交双向小波包

为了将正交双向小波包推广到高维情形φan+λ(t)=∑k∈Zdp+k,λφn(At-k)+p-k,λφn(k-At),构造了伸缩因子为矩阵A的正交双向小波包{φan+λ(t),λ=0,1,…,a-1}n∈Z+,分别从时频域角度通过小波包基函数的正交性研究了高维正交双向小波包的性质,得到了小波包子空间的分解算法、重构算法及频域表示为∏∞j=1Pλjωa()jΦ0(0)。     

具有矩阵伸缩的正交双向小波包

为了将正交双向小波包推广到高维情形φan+λ(t)=∑〖DD(X〗k∈Zdp+k,λφn(At－k)+p－k,λφn(k－At),构造了伸缩因子为矩阵A的正交双向小波包{φan+λ(t),λ=0,1,…,a－1}n∈Z+,分别从时频域角度通过小波包基函数的正交性研究了高维正交双向小波包的性质,得到了小波包子空间的分解算法、重构算法及频域表示为∏ SymboleB@ j=1P λjωajΦ^0(0)。
     

[0,1]区间上一种双正交小波的构造

先构造[0，1]区间上分片多项式初始小波空间，再利用Legendre正交多项式构造上双正交小波空间，文章最后对线性情形举出例子。     

二元正交多项式小波

在一元正交多项式的基础上，定义了二元正交多项式。由此引入二元正交多项式空间的核多项式，用核多项式定义尺度函数，用张量积构造二元正交多项式小波。研究了尺度函数和小波函数的性质，给出了两尺度关系及分解式，把一元正交多项式小波进行推广，使之应用范围更加广泛。     

新金属间化合物YA1 0.27Ge2的晶体结构

用X射线粉末衍射技术和Rietveld全谱图拟合法研究新金属间化合物YA1 0.27Ge2的晶体结构，该化合物为正交晶系，空间群为Cmcm（No．63），a=0．41149（2）nm，b=1．62979（7）nm，c=0．39522（2）nm，Z=4，Dx=6．054g／cm^3，为CeNiSi2结构类型。     

伸缩因子为a的r重正交平衡的多小波

Lebrun引入平衡多小波的概念， 并构造正交平衡的多尺度函数和多小波.这种平衡的多尺度函数和多小波在处理离散的多项式信号时能被低通滤波器特征化而被高通滤波器取消.文中将平衡多小波的概念推广到伸缩因子为a的情形（a≥2，a∈Z）. 建立了伸缩因子为a的r重正交平衡多尺度函数的一些等价关系. 并基于这些等价关系给出一种构造正交平衡多小波的算法.最后给出伸缩因子为2和3两种情形下的平衡多小波的构造算例.     

r=4的插值正交多小波的对称和平衡性的讨论

首先利用正交多小波满足完全插值性的条件,给出了r=4的正交多小波矩阵滤波器满足的参数化形式.其次,根据矩阵滤波器满足对称的条件,可证明与r=2一样不存在对称的插值正交多尺度函数.最后,由上面的参数化形式,更进一步给出了当多小波满足一阶平衡时滤波器应满足的条件.     

重数为4的正交多小波

讨论了双尺度方程：φ(x)=∑^2k=0 hkφ（2x-k)，其中,φ是一个含四个分量的函数向量，h0,h1和h2都是4阶实矩阵，推导出h0,h1,h2的显示表达式，使得尺度函数具有短支集、对称性或反对称性和正交性。同时构造出相应的正交小波向量，这些小波具有与尺度函数类似的性质。     

单节点3次样条空间上的正交基

正交基在许多问题中有重要的应用.在计算机辅助设计中所常用的B样条基不是正交基.尝试构造三次样条空间中的一组正交基.给定区间[a,b]上的一个节点向量a=t0相似文献   

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).     

Integrating GIS Web services based on mediating architecture

The geographic information service is enabled by the advancements in general Web service technology and the focused efforts of the OGC in defining XML-based Web GIS service. Based on these models, this paper addresses the issue of services chaining,the process of combining or pipelining results from several interoperable GIS Web Services to create a customized solution. This paper presents a mediated chaining architecture in which a specific service takes responsibility for performing the process that describes a service chain. We designed the Spatial Information Process Language (SIPL) for dynamic modeling and describing the service chain, also a prototype of the Spatial Information Process Execution Engine (SIPEE) is implemented for executing processes written in SIPL. Discussion of measures to improve the functionality and performance of such system will be included.