安全的多级门限多秘密共享

为克服已有门限方案只能在同一级门限下共享秘密的限制,利用离散对数计算和大数分解的困难性,提出一种可认证的多级门限多秘密共享方案。通过一个多项式共享秘密,该多项式在不同级门限中退化为不同的低阶多项式。与已有诸多秘密共享方案相比,该方案可以同时有多级门限值,而在同级门限下又可以有多个秘密。恢复任意一级门限的任意一个秘密都不会影响其他未恢复秘密的安全性。该方案只要求每个参与者掌握一个子秘密,管理和使用都比较方便。     

安全的多级门限多秘密共享

为克服已有门限方案只能在同一级门限下共享秘密的限制,利用离散对数计算和大数分解的困难性,提出一种可认证的多级门限多秘密共享方案。通过一个多项式共享秘密,该多项式在不同级门限中退化为不同的低阶多项式。与已有诸多秘密共享方案相比,该方案可以同时有多级门限值,而在同级门限下又可以有多个秘密。恢复任意一级门限的任意一个秘密都不会影响其他未恢复秘密的安全性。该方案只要求每个参与者掌握一个子秘密,管理和使用都比较方便。     

关于两个不同访问群体的秘密共享方案

根据秘密共享的含义,针对目前秘密共享方案不能解决两个具有不同访问权限的群体的秘密共享问题,引入(s+q,m+n)(qmin{n,s})门限秘密共享的概念;结合微分几何和密码学理论,提出有限域Zp上的参数曲线在实数区间(a,b)内可微的思想.利用平面上曲线的主密钥点Q(k)处的法线与切线的交点来构建(2+1,m+n)情形的门限体制;利用空间曲线的主密钥点Q(k)处的超法面与切线的交点来构建(s+q,m+n)(s≥3)情形的门限体制.经证明该门限方案满足秘密共享的重构要求和安全性要求,是一个完备的秘密共享方案.结果显示,该门限方案具有几何直观、主密钥的单参数表示、可扩充新的秘密共享参与者的优点,是一个具体实用且易于实现的秘密共享方案.     

基于线性方程组的秘密共享方案

在门限方案中,密钥被所有成员秘密共享,而当一定数量的成员合作时,该密钥可以恢复.一个(t,n)门限方案就是将密钥K分给n个成员,而任意t个成员合作可以生成密钥K,但只有t-1个成员或者更少的成员不能生成该密钥.大多数(t,n)门限方案都基于Lagrange插值多项式或者是同余理论.文章提出了一种新的基于多元一次多项式的秘密共享门限方案.     

一个基于状态树的(t, n)秘密共享方案

在简述已有(t,n)秘密共享方案的基础上,提出了一个直观、简洁有效的基于状态树的(t, n)秘密共享方案,包括设计考虑、算法描述、算法实例,并对该方案进行了分析。分析表明,该方案秘密分割算法具有多项式复杂度,秘密重建算法具有线性复杂度,满足门限机密性和门限可用性。     

基于特殊访问权限的差分秘密共享方案

提出了一个安全的门限秘密共享方案,利用齐次常系数线性差分方程的结构及其解的结构,实现了具有不同访问权限的成员参与的秘密共享,并给出了(m+u,t+1)门限方案的概念.     

基于正交向量的秘密共享方案

利用正交向量的特性以及拉格朗日插值多项式,提出一种（m,n）门限秘密共享方案和一种（m＋n,t1＋t2）门限秘密共享方案。这两种方案可以预防参与者之间的互相欺诈以及不诚实分发者的欺诈行为,且容易实现系统共享密钥的更新。系统中的秘密分发者能比较简单地实现成员的增加与删减。     

基于二元多项式与中国剩余定理的多秘密分享方案

在基于单向函数和二元多项式的秘密分享方案的基础上,利用中国剩余定理构造了一个(t+1,n)门限可验证的多秘密分享方案.这个方案便于成员加入和系统的更新.     

基于线性方程组的秘密共享方案

在门限方案中,密钥被所有成员秘密共享,而当一定数量的成员合作时,该密钥可以恢复.一个(t,n)门限方案就是将密钥K分给n个成员,而任意t个成员合作可以生成密钥K,但只有t-1个成员或者更少的成员不能生成该密钥.大多数(t,n)门限方案都基于Lagrange插值多项式或者是同余理论.文章提出了一种新的基于多元一次多项式的...     

基于双线性对的可验证门限秘密共享方案

基于双线性对提出了一个门限秘密共享方案.在秘密重构和恢复过程中,都可以验证每个参与者是否存在欺诈行为;在参与者间不需要安全信道.分析表明,该方案是一个安全、实用的门限秘密共享方案.     

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.     

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.     

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-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the