基于遗传神经网络的报价决策模型研究

针对承包商在决定投标后,进行报价决策过程中的种种难题,利用人工智能技术的两个分支:遗传算法和神经网络,建立了一个报价决策模型。并在MATLAB环境下对模型进行了初步实现,将从大量成功报价中标的工程实测中得来的数据作为样本对网络进行了训练和检验。     

分形插值曲线的MATLAB实现

自然界中存在的许多现象具有分形特征,传统的Euclid 空间对具有分形特征的自然界形态仿真具有一定困难.对此可以用分形插值来拟合自然界形态.分形插值函数是由迭代函数系统(IFS)实现的.通过离散的数据点构成分形插值函数,可以证明分形插值函数是这个IFS唯一的吸引子.利用MATLAB矩阵运算与图形绘制功能,实现离散数据点的分形插值拟合.试验结果表明.该算法具有简捷直观的特点.     

三维脑分割中灰度阈值的选取方法

三维人脑体数据分割是医疗图像处理中的一项重要技术,其中阈值的选取最为关键。在介绍了3种具有代表性的图像阈值求取方法的基础上,将它们分别用于分割实验;从实验效果及算法性能两方面对这3种方法进行比较,结果表明模糊最大熵结合遗传算法求取阈值的方法效果较好,受噪声影响小。     

明党参的遗传多样性研究

 对珍稀特有单种属植物明党参的4个居群的材料,从物种生物学及保护生物学的角度,对它们 的遗传多样性进行了研究和分析。研究结果表明：各居群染色体数目恒定(2n=20),核型类型均为2A型,居群间存在核型多型性,主要表现为染色体的杂合性及随体染色体的位置也有一定变化。采用淀粉凝胶电泳方法,分析了10个酶系统,获得19个基因位点的资料,分析结果表明：居群的遗传变异处于较低水平,多态性位点比率P=33.35％,等位基因平均数A=1.43,等位酶基因多样度指数 Ho：0.03,He=0.07。总的基因位点变异中,有58％的变异来自于居群间,42％的变异存在于居群内,居群杂合体过量的位点仅为13％。偏东部居群的遗传多态性比西南部居群高。根据明党参居群遗传变异式样并结合相关研究,提出了其遗传多样性保护策略。     

皮亚杰的学习理论和人的发展

介绍了皮亚杰发生认识论的基本内容,探讨了发生认识论的主要的哲学基础以及作为其思想基础的结构主义和生命系统理论。皮亚杰吸取了康德的主体能动性和知识是建构的思想,黑格尔的整体观和辩证法的思想,亚里士多德的逻辑范畴和规律的观点,吸收了结构主义和生命系统理论的营养,形成发生认识论的精髓,也是建构主义的核心思想。通过对发生认识论理论来源的探讨,深刻理解皮亚杰教育思想基本意义,从而认识到源于其理论的建构主义学习理论成为当前教育改革的主要的理论基础的原因。     

转基因育种

本文对植物基因工程中的受体系统、载体系统及其它转化方法作了较全面的介绍,着重探讨了农杆菌Ti质粒转化系统,同时对外源基因的表达问题了进行了初步分析。     

基于信号源能量模型的传感器网络追踪算法研究

比较了应用于传感器网络声源追踪定位的3种模型,其中信号源能量模型对数据处理简单,更利于节省能量。针对现有基于信号源能量模型的算法的不足,给出了一种全新的算法—梯度迭代算法,并通过仿真实验证明了其在追踪的精确度和速度方面具有明显的优势。     

Seymour Benzer and T4 <Emphasis Type="Italic">r</Emphasis>II

One of the goals of genetics is to understand genes in as much detail as possible. For instance, with respect to a given gene, one would like to know its chromosomal location, its physical and genetic size, its neighbours, the number of mutations/alleles defining the gene, the order of mutations, the genetic/physical distance between them, etc. Thus, rather than focusing on the whole genome, one focuses on the finer details of a given genetic segment. The exercise of probing such details is called ‘fine structure genetic analysis’. There are several pioneers who have contributed enormously to this area in many bacterial and phage systems. Two stalwarts, Seymour Benzer and Charles Yanofsky, stand preeminent among them. In the following pages I present briefly Benzer’s outstanding work on the fine structure of the rII region of bacteriopage T4. These path-breaking studies contributed significantly to our understanding of the structure, organization and function of genes. R Jayaraman is an Emeritus Professor of Molecular Biology at the School of Biological Sciences, Madurai Kamaraj University, Madurai, where he taught and carried out research in the area of microbial genetics for three decades.     

Genetic analysis for brix weight per stool and its component traits in sugarcane (Saccharum officinarum)

Brix weight per stool (BW) of sugarcane is a complex trait, which is the final product of a combination of many components. Diallel cross experiments were conducted during a period of two years for BW and its five component traits, in- cluding stalk diameter (SD), stalk length (SL), stalk number (SN), stalk weight (SW), and brix scale (BS) of sugarcane. Phenotypic data of all the six traits were analyzed by mixed linear model and their phenotype variances were portioned into additive (A), dominance (D), additive×environment interaction (AE) and dominance×environment interaction (DE) effects, and the correlations of A, D, AE and DE effects between BW and its components were estimated. Conditional analysis was employed to investigate the contribution of the components traits to the variances of A, D, AE and DE effects of BW. It was observed that the heritabilities of BW were significantly attributed to A, D and DE by 23.9%, 30.9% and 28.5%, respectively. The variance of A effect for BW was significantly affected by SL, SN and BS by 25.3%, 93.7% and 17.4%, respectively. The variances of D and DE effects for BW were also significantly influenced by all the five components by 5.1%～85.5%. These determinants might be helpful in sugarcane breeding and provide valuable information for multiple-trait improvement of BW.     

Identification of Rhodiola species by using RP-HPLC

INTRODUCTION The roots of Rhodiola species, one of the im-portant traditional Chinese herbal medicines, have anti-viral (Sun et al., 1993), anti-tumor (Wang et al., 1992), anti-ageing (Yi et al., 1992), anti-oxygen de-ficiency, anti-radiation (Luo et al., 1996) effects and other pharmacological properties (Xu et al., 2000). Ten Rhodiola species distribute in the Tianshan Mountains areas of China. Biologically active com-pounds content in the roots has large variation and the value of…