一种基于聚类分析的数值积分新算法

通过聚类分析找出一般数值求积公式的被积函数出现数值信息波动较大的区域,自适应地采用相应的高精度公式,构造出高精度的自适应数值求积公式.数值试验结果表明,这种新数值求积算法较一般数值求积公式,能显著地减少数据存储量和计算量,提高数值求积公式的稳定性和数值积分的精度.     

Breaking biological symmetry in membrane proteins: The asymmetrical orientation of PsaC on the pseudo-C2 symmetric Photosystem I core

The elucidation of assembly pathways of multi-subunit membrane proteins is of growing interest in structural biology. In this study, we provide an analysis of the assembly of the asymmetrically oriented PsaC subunit on the pseudo C₂-symmetric Photosystem I core. Based on a comparison of the differences in the NMR solution structure of unbound PsaC with that of the X-ray crystal structure of bound PsaC, and on a detailed analysis of the PsaC binding site surrounding the F_X iron-sulfur cluster, two models can be envisioned for what are likely the last steps in the assembly of Photosystem I. Here, we dissect both models and attempt to address heretofore unrecognized issues by proposing a mechanism that includes a thermodynamic perspective. Experimental strategies to verify the models are proposed. In closing, the evolutionary aspects of the assembly process will be considered, with special reference to the structural arrangement of the PsaC binding surface. Received 22 October 2008; received after revision 17 November 2008; accepted 05 December 2008     

Dark matter,the Equivalence Principle and modified gravity

Dark matter (DM) is an essential ingredient of the present Standard Cosmological Model, according to which only 5% of the mass/energy content of our universe is made of ordinary matter. In recent times, it has been argued that certain cases of gravitational lensing represent a new type of evidence for the existence of DM. In a recent paper, Peter Kosso attempts to substantiate that claim. His argument is that, although in such cases DM is only detected by its gravitational effects, gravitational lensing is a direct consequence of Einstein's Equivalence Principle (EEP) and therefore the complete gravitational theory is not needed in order to derive such lensing effects. In this paper I critically examine Kosso's argument: I confront the notion of empirical evidence involved in the discussion and argue that EEP does not have enough power by itself to sustain the claim that gravitational lensing in the Bullet Cluster constitutes evidence for the DM Hypothesis. As a consequence of this, it is necessary to examine the details of alternative theories of gravity to decide whether certain empirical situations are indeed evidence for the existence of DM. It may well be correct that gravitational lensing does constitute evidence for the DM Hypothesis—at present it is controversial whether the proposed modifications of gravitation all need DM to account for the phenomenon of gravitational lensing and if so, of which kind—but this will not be a direct consequence of EEP.     

末端修正子母弹对面目标的射击效能评估

作为射击精度评估的常用指标,无论是圆概率偏差,还是命中概率都没有涉及面目标的功能结构的重要度,而命中重要程度不同的区域,其射击效能是不同的。针对末修子母弹打击面目标时射击效能的评价问题,在通过数值模拟法产生末修子母弹的落点散布,以及利用毁伤树分析方法对面目标进行功能区域划分的基础上,利用Monte-Carlo仿真方法计算了子母弹对各功能区域的命中概率Pi,并定义了基于区域结构及重要度的射击命中度和毁伤概率,从而综合评估了整体的射击效能。最后通过仿真算例说明了该方法的合理性,并利用均匀设计法定量分析了末修子母弹的性能参数对射击效能的影响。     

影响植物生长因素的模糊聚类分析研究

通过对影响植物生长因素的模糊聚类分析研究,实现了对主要因素的主从排序,进而形成了对地域、地块的适宜度评价,从而为植物的合理布局与规划提供了可以信赖的数量依据     

多元统计分析在河流污染状况综合评价中的应用

以湟水流域为例 ,针对流域内具有代表性的断面 ,运用因子分析方法和聚类分析方法就各断面水质污染程度和污染相似性进行定量化的综合评价 ,并以判别分析方法对相关结果加以校验 ,为河流治污工作的开展提供一定的科学依据 .     

基于重复博弈的集群企业间社会关系构建分析

针对我国外生模式及混合内生模式集群中核心企业与依附企业间的主从支配关系,将核心企业与依附企业间的社会关系收益进行量化,讨论了核心企业与依附企业间的社会关系构建及维持的影响因素及内在机制.研究表明,核心企业与依附企业间的社会关系构建与维持取决于核心企业对双方社会关系价值的预期以及依附企业的市场价格;核心企业依据依附企业的市场价格来分割双方的社会关系收益;而依附企业可以通过提高自身的价值,获取更高的社会关系收益分割值,缔结和维持有利于自身和集群成长的社会关系.     

Apusic与JBoss的集群策略分析与研究

在服务器集群中,负载均衡是一个关键部分,它是集群系统中任务分配的核心环节.该文在比较3种负载均衡策略的基础上分析了JBoss应用服务器集群负载均衡策略的特点,对国内第一个自主知识产权Apusic应用服务器负载均衡策略进行了分析,给出了其实现方法.     

基于WINDOWS平台的集群构建研究

对集群相关技术进行分析，阐述了基于Windows平台的双机集群的三种应用模式，并以其中的双机热备模式为例，完成了图书馆管理系统的模拟构建方案，保障了系统的安全性和高可用性。     

Language clusters based on linguistic complex networks

To investigate the feasibility of using complex networks in the study of linguistic typology, this paper builds and explores 15 lin-guistic complex networks based on the dependency syntactic treebanks of 15 languages. The results show that it is possible to classify human languages by means of the following main parameters of complex networks: (a) average degree of the node, (b) cluster coefficients, (c) average path length, (d) network centralization, (e) diameter, (f) power exponent of degree distribution, and (g) the determination coefficient of power law distributions. The precision of this method is similar to the results achieved by means of modern word order typology. This paper tries to solve two problems of current linguistic typology. First, the language sample of a typological study is not real text; second, typological studies pay too much attention to local language structures in the course of choosing typological parameters. This study performs better in global typological features of language and not only enhances typological methods, but it is also valuable for developing the applications of complex networks in the humanities, social, and life sciences.