算子非精确条件下确定正则化参数的一种方法

基于非标准的广义偏差原则,在算子及观测数据都有扰动的条件下,对于求解不适定问题的Tik-honov正则化方法,给出了一种选取正则化参数的简单迭代算法,并阐明了该迭代算法是一种线性模型函数算法.进一步地,利用线性模型函数方法,在一定条件下证明了所提出的选取正则化参数的简单迭代算法是收敛的,并通过数值算例验证了该方法的有效性.     

一种特殊的下降算法——分裂梯度法

求解无约束优化问题,常用的方法有下降算法,牛顿法,共轭梯度法等。当目标函数为几个光滑函数的和时,一些学者提出并研究了增量梯度算法。其基本思想是循环选取单个函数的负梯度作为迭代方向。增量梯度算法的迭代方向不一定是下降方向,所以不能用下降算法的一维搜索确定步长,因为受限于步长的选择,收敛效率不高。本文结合了下降算法和增量梯度算法的思想,提出了分裂梯度法。简单的说,分裂梯度法循环考虑单个函数的负梯度方向,如果这一方向是下降方向,则选择这一方向为迭代方向;否则选取函数的负梯度方向为迭代方向。最后通过数值实验与最速下降算法、随机下降算法以及增量梯度算法进行对比,结果表明对于某些优化问题,采用分裂梯度法更有效。     

无约束优化的非单调三次正则BB算法

先利用BB(Barzilai Borwein)类型参数构造目标函数Hessian矩阵的近似矩阵, 通过极小化当前迭代点处的三次正则化近似梯度模型求解试探步, 再结合非单调线搜索策略提出一个非单调三次正则BB算法, 最后给出算法的收敛性证明. 数值实验结果表明, 该算法数值性能良好.     

无约束优化的非单调三次正则BB算法

先利用BB(Barzilai Borwein)类型参数构造目标函数Hessian矩阵的近似矩阵, 通过极小化当前迭代点处的三次正则化近似梯度模型求解试探步, 再结合非单调线搜索策略提出一个非单调三次正则BB算法, 最后给出算法的收敛性证明. 数值实验结果表明, 该算法数值性能良好.     

求解拟变分不等式问题的一类无导数下降算法

利用广义正则gap函数的方向导数,构造了一种迭代方向,提出了一类求解拟变分不等式问题的算法。此算法不需关心目标函数的梯度计算问题,与相关文献比较,该算法的适用范围更加广泛。在某些假设条件下,证明算法的收敛性。     

分布式HDP领导-跟随者系统最优一致控制研究

为研究行为未知的非线性多智能体系统领导-跟随者最优一致控制问题,针对智能体动态方程未知的情况,设计神经网络辨识器学习智能体动力学行为;构造以多智能体系统局部误差为输入的性能指标函数,将多智能体系统领导-跟随者一致性问题转换为求解智能体局部性能指标函数最优值的优化控制问题;结合自适应动态规划思想设计分布式迭代算法求解该优化问题,并讨论了算法的收敛性;设计基于神经网络的评价-执行结构分布式控制器来近似局部性能指标函数,通过神经网络学习迭代寻找局部性能指标函数的最优解,实现多智能体系统的最优一致控制策略。设计的分布式控制器能够根据智能体状态数据自适应产生控制策略,使多智能体系统趋于一致。     

虚拟参考反馈校正控制器参数的预测误差辨识

针对未知系统中双控制器的设计问题,采用虚拟参考反馈校正方法,通过最小化由一组观测数据组成的L2范数所构成的代价函数,达到直接设计控制器目的.联合前馈控制器分离出的固定部分和反馈控制器作为滤波器,对原输入/输出关系式进行重参数化,得到标准的预测误差辨识形式,在所得式中,对控制器未知参数矢量采用可分离迭代的非线性最小二乘法进行估算.文中还对算法的收敛性进行了理论分析,并通过仿真验证了所提方法的有效性.     

非精确线搜索下一类新的混合共轭梯度法研究

共轭梯度法在求解无约束最优化问题中起着重要作用。通过构造一个新的参数βk^＊,并与βk^DY结合,得到了一类新的混合迭代参数,此类混合共轭梯度法在迭代过程中保持下降性;在非精确强wolf线搜索下此算法具有全局收敛性。     

基于在线模型辨识的飞行器多约束复合制导技术

针对飞行器再入制导问题,该文引入控制变量参数化、积分问题转换和在线模型辨识等技术,提出一种跨周期迭代的可行轨迹预测校正算法,并结合标称轨迹跟踪算法形成一套多约束复合制导方案。利用一种复合高度-速度(height velocity,HV)飞行走廊,将再入轨迹规划问题简化为单调函数寻根问题。为提高射程预测计算效率,引入Gauss-Legendre求积公式,将积分问题转化为函数计算问题。采用递推最小二乘估计方法,收集历史预测信息,实现模型在线辨识功能,并采用跨周期Newton-Raphson方法完成高度权重系数的在线修正。在标称轨迹跟踪器设计的基础上,开展飞行器数值仿真试验,结果表明:基于在线模型辨识的复合制导方法具有显著的速度优势,且具有优异的自主性和自适应能力。     

双线性系统的一种辨识方法的研究—沃尔什函数迭代算法及其应用

本文对一类直接可观测的双线性系统用沃尔什函数方法进行辨识的问题,进行了一些探讨,把原来的沃尔什函数辨识方法改进为一种迭代算法,从而较好地提高了系统辨识的精确度。通过数字仿真,讨论了函数用沃尔什级数近似的项数以及采用不同的输入信号对辨识精确度的影响,验证了这种辨识方法在有噪声存在时的有效程度。为了验证这种方法用于实际系统的可能性,对一个实际的热交换器进行了辨识,结果表明,对于那些近似于双线性的实际过程,沃尔什函数迭代算法是一种有效的辨识方法、     

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-