大规模无约束优化的非单调有限内存BFGS算法

结合有限内存及非单调搜索技术提出了求解大规模无约束优化的非单调有限内存BFGS(NLBFGS)算法,在一定的条件下给出了算法收敛性结论.从标准试验函数库CUTE中选择标准函数,与线搜索满足强Wolfe条件的L-BFGS算法相对比进行了数值试验,结果表明算法是较为满意的.     

一种新的修正有限内存拟牛顿法

依据修正拟牛顿方程,提出一种新的双循环有限内存拟牛顿法.与经典的有限内存BFGS方法相比,新算法同时利用函数值和梯度信息构造拟牛顿校正矩阵,且不会增加计算量,理论分析和数值检验说明了新算法的有效性。     

一类拟牛顿算法的收敛性

根据一类基于新拟牛顿方程Bk 1sk=yk*的修改BFGS类算法,采用广义W olfe线搜索模型(GW搜索模型):f(xk 1)≤f(xk) δkαgTkdk和g(xk 1)Tdk≥m ax{,σ1-(kα‖dk‖)p}gTkdk,其中0<δ≤σ<1,p∈(-∞,1),得到一类修正的BFGS算法(M BFGS),证明了M BFGS算法的全局收敛性和超线性收敛性.数值试验结果表明M BFGS算法是有效的.     

求解病态线性方程组的混合算法

首先通过变分原理将求解线性方程组的问题转化为等价的求解无约束函数最优化问题的极小值.通过研究BFGS算法和模拟退火算法的优缺点,鉴于BFGS的良好的局部搜索能力以及模拟退火法的全局搜索能力,提出了一个BFGs-SA的混合算法.数值实验表明该混合算法校正了BFGS的局部搜索能力,达到了全局最优解,从而得到了原病态线性方程组的解.     

扰动谱尺度BFGS算法及收敛性分析

在前人提出的扰动BFGS算法的基础上,结合谱尺度算法的思想,提出一种扰动谱尺度BFGS算法,建立算法的全局收敛性定理,本研究证明该扰动谱尺度BFGS算法在一定条件下采用单调Wolfe-Powell型线性搜索和非单调Wolfe-Powell型线性搜索均具有全局收敛性,同时还证明采用单调Wolfe-Powell型线性搜索具有2-线性收敛性.     

采用WOLFE搜索的BFGS—SQP算法

X.Chen给出了一个用于解决LC^1线性约束优化问题的BFGS－SQP算法,这个算法是用Armijo线性搜索原则来求步长的。采用Wolfe线性搜索原则来替代该BFGS－SQP算法的Armijo原则,经过类似的分析,同样得到了BFGS－SQP算法的全局收敛性及超线性收敛性。     

基于BFGS方法的拥塞速率控制算法

针对TCP/AQM对偶性模型采用梯度投影方法调整链路价格收敛速度慢的问题,使用具有更快收敛速度的BFGS方法来进行链路价格的计算,提出一种基于BFGS方法的拥塞速率控制算法.仿真结果证明,利用BFGS方法所设计拥塞速率控制算法具有更快的收敛速度,算法性能优于其它算法.     

支持向量机子问题的算法研究

求解支持向量机大规模分类问题时,系数矩阵的存储和计算是非常困难的.借助分解技术,把问题分解成多个维数较低的二次规划问题.利用增广拉格朗日函数将子问题转化成只含有界约束的形式,再用修正子空间有限记忆BFGS方法解子问题,节省了存储空间,提高了求解效率.     

改进的BFGS算法在一种新搜索下的收敛性

李正峰提出了一类改进的BFGS算法,并在目标函数为一致凸的条件下,证明了带有Wolf线搜索的该算法具有全局收敛性.刘光辉提出了一种与回追搜索(backtracking linesearch)有关的可行线性搜索.证明在这种新搜索下,改进的BFGS算法亦-具有全局收敛性.     

基于新拟牛顿方程的一类超线性收敛的改进BFGS算法

针对无约束最优化问题,在已建立的一类新拟牛顿方程的基础上,把满足于传统拟牛顿方程的一类改进BFGS算法推广到新拟牛顿方程,从而得到一类基于新拟牛顿方程的改进BFGS算法.证明该算法在目标函数为一致凸时具有局部超线性收敛性.     

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.     

Lower Paleozoic oil relationships within Williston Basin, Canada

The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.     

An Analysis of Catherine＇s Character——Wuthering Heights

Wuthering Heights, Emily Bronte＇s only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.     

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.     

Design and analysis of generic LBS application developing platform

Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.     

橡胶颗粒沥青混合料低温抗裂性试验研究

以AC-13级配为基础,将橡胶颗粒代替部分集料掺入混合料中,以低温弯曲试验为评价方法对不同橡胶颗粒掺量下沥青混合料的低温抗裂性进行研究,并引入应变能密度值对混合料的低温抗裂性进行综合评价.试验结果表明:橡胶颗粒沥青混合料试件的破坏微应变均超过2 300,满足冬寒区的技术指标;无论是否掺加橡胶颗粒,随着温度的下降,沥青混合料破坏时的最大弯拉强度增大,弯拉应变降低,劲度模量增大;弯曲应变能密度在胶粒掺量为1%左右时具有较大的弯曲应变能密度值,此时橡胶颗粒沥青混合料具有较好的低温抗裂性.     

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。     

A computer generator for randomly layered structures

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

Quantitative trait loci （QTLs） for quality traits related to protein and starch in wheat

Quality traits in wheat （Triticum aestirum L.） were studied by quantitative trait locus （QTL） analysis in a recombinant inbred line （RIL） population, a set of 131 lines derived from Chuan 35050 × Shannong 483 cross （ChSh）. Grains from RILs were assayed for 21 quality traits related to protein and starch. A total of 35 putative QTLs for 19 traits with a single QTL explaining 7.99-40.52% of phenotypic variations were detected on 10 chromosomes, 1D, 2A, 2D, 3B, 3D, 5A, 6A, 6B, 6D, and 7B. The additive effects of 30 QTLs were positive, contributed by Chuan 35050, the remaining 5 QTLs were negative with the additive effect contributed by Shannong 483. For protein traits, 15 QTLs were obtained and most of them were located on chromosomes 1 D, 3B and 6D, while 20 QTLs for starch traits were detected and most of them were located on chromosomes 3D, 6B and 7B. Only 7 QTLs for protein and starch traits were co-located in three regions on chromosomes 1D, 2A and 2D. These protein and starch trait QTLs showed a distinct distribution pattern in certain regions and chromosomes. Twenty-two QTLs were clustered in 6 regions of 5 chromosomes. Two QTL clusters for protein traits were located on chromosomes 1D and 3B, respectively, three clusters for starch traits on chromosomes 3D, 6B and 7B, and one cluster including protein and starch traits on chromosome 1D.     

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.