具有隐私保护的外包数据库合计查询方案

针对外包数据库中数据的隐私性和安全性问题,提出一种具有隐私保护的外包数据库合计查询方案.利用Mignotte 秘密共享方案将数据所有者的数据库外包给服务提供者,服务提供者根据用户提出合计查询要求,在不泄露外包数据的前提下协同计算查询并将结果响应给用户,用户根据数据所有者对数据项的Pedersen承诺和生成的Merkle 哈希树对结果进行验证.研究结果表明:在查询过程中,该方案能够保证数据项和中间结果的隐私性和安全性;在数据所有者可信的前提下,用户能够验证查询结果;与同类方案相比,该方案具有更高的效率.     

面向多用户的多层嵌套数据库加密方案

围绕外包数据的安全性问题与用户隐私性问题,展开对加密数据库方案的研究,提出了一个面向多用户的多层嵌套数据库加密方案.该方案根据洋葱模型多层理论,采用多种不同类型的加密算法对用户的外包数据进行多层嵌套加密,实现了既保证数据机密性又满足多种不同SQL查询类型的数据库加密方案.针对用户递交包含敏感信息的查询语句在一定程度上泄露用户自身的隐私这一问题,设计了基于单服务器私有信息检索(private information retrieval,PIR)技术的用户隐私保护机制,实现了用户匿名查询.安全性分析表明,该方案满足数据机密性与用户隐私性.Sysbench基准测试实验分析表明,该方案具有良好的查询处理效率、读写吞吐量以及健壮性.     

数据仓库的多维数据分析器设计与实现

实现多维数据分析是数据仓库系统需要具备的一个主要功能，它接受用户的多维数据查询请求，生成多维数据集，为建立数据挖掘模型提供基础效果。本文讨论了基于Microsoft SQL Server2000的多维数据分析器的实现。简要介绍了多维数据分析的基本原理，并在DSO、ADO／MD及MDX（多维数据表达式）等技术的基础上，构造了一个多维数据分析器。最后，给出了多维分析器的实现实例。     

一种适应于动态环境范围查询的数据立方体

范围查询是对数据立方体进行数据分析的有效方法,预计算技术可以提高数据立方体范围查询的速度,实现快速的用户响应.近年来研究人员基于多维联机分析处理(MOLAP)预计算的研究主要以prefix sum及分块技术为基础,本文对分块方案及如何组织块内单元实施prefix sum方法进行探索,提出了前缀区域数据立方体结构(Prefix Region Cube,PRC),采用基于前缀区域的不规则的分块方案,这种分块方法利于从起始单元开始的前缀区域范围查询的实现.另外PRC在分块及对划分后的块内单元实施prefix sum时都采用回归分割技术,在不增加额外立方体空间的前提下,实现范围查询和数据更新的代价都为O(logdn).     

外包空间数据库的完整性保证机制

存储在云计算服务提供商上的用户数据可能被篡改或删除,查询完整性验证方案的作用是确保查询用户能够验证查询结果中的数据是真实的且包含所有满足条件的数据.本文在现有验证树结构基础上进行改进,提出了一种空间验证数据结构VSS-tree.利用SS-tree作为基本结构并为其附加验证信息,采用边界球进行区域划分增大了节点的度,有效降低了验证树的高度,并避免了不必要的磁盘访问,从而提高了空间查询验证的处理效率.实验结果表明,该方案比MR-tree具有更好的性能.     

决策支持系统中OLAP的设计与实现

目的设计和实现对数据仓库中的信息进行决策分析的OLAP。方法以零售企业销售预测为切入点,研究决策支持系统中OLAP的设计。结果建立了用来进行OLAP分析的多维数据集,并对多维数据集中的数据用切片、切块、钻取和旋转等方式进行分析,用MDX多维查询语言对多维数据集中的数据进行复杂查询,提出了对OLAP分析数据展现的3种解决方案。结论在研究决策支持系统中OLAP的基础上,建立和实现了对数据仓库进行决策分析的OLAP。     

基于并行数据仓库的数据分布调整策略

并行数据仓库系统的性能与数据在多处理机之间的分布密切相关.本文根据并行数据仓库系统的体系框架,提出了全新的并行数据仓库数据三层模式结构,并在此模式基础上,根据用户查询的变化设计了动态多维数据分布和调整策略,通过改变数据分布模式和数据物理存放的方式来保证系统数据分布均匀和工作负载均衡.实验结果证明,此算法能有效地缩短OLAP平均查询响应时间,提升系统的整体性能.     

时序数据多维聚合查询服务的实现

随着电能质量监测点不断扩大,产生海量具有时序特性的多维电能质量数据,当前的诸多数据查询方法不能适应电网电能质量监测数据的交互式多维聚合查询需求。研究提出时序数据多维聚合服务的实现方法,为内存中预聚合后的任务结果建立哈希存储结构,对实时数据建立位图索引存储结构,将历史数据的预聚合数据尽量存储于内存中,改进随机读写的低性能问题,提升查询效率,解决交互式查询问题。同时运用最优聚合任务算法选择出尽量多的预聚合任务数,提高交互式查询命中率。实验验证了该算法的可行性,与分组二维背包算法相比,在预聚合任务数量选择方面具有一定优势。     

OLAP在现代企业DSS中的应用研究

如何迅速从海量数据中获得准确的决策信息是现代商业企业致胜的关键。以数据仓库及OLAPServices为工具,通过建立多维数据模型和数据立方体,针对企业销售数据设计一个数据仓库管理系统,把事务数据库中原始混乱的数据集成转化变成数据仓库中规范的数据方便用户的查询,进而辅助企业决策。实际证明系统实用方便,大大提高企业信息管理效率。     

基于元数据的异构数据集整合方案

为了把分布在不同系统中的异构数据集整合起来,实现高度集成的数据查询功能,需要一种普适性方案对数据进行规范化与再利用。该文对典型的应用系统分布场景进行建模,制定一种伸缩性良好的元数据规范,进而提出一种可对分散系统中的异构数据集进行集成,对集中的元数据信息进行统一管理,并为用户提供单一入口查询的整合方案。对原始系统的改造极小,且用户可以透明地访问原始系统的所有数据资源。方案已经应用在医药卫生科学数据共享工程中,取得了可观的经济效益。     

Markedness and its Interpretation in Language Use

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.     

Features of Women's language

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.     

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.     

低渗透非均质砂岩油藏启动压力梯度研究

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。     

On Tragic Consciousness In The Works By Ernest Hemingway

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.     

A computer generator for randomly layered structures

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

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.     

Jane Eyre——A Feminist In The 19th Century

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.     

Achieving Unusual States of Matter Under High Pressure

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-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

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-