混沌遗传算法

利用混沌序列来构造遗传算子,使不同代之间从短期看似随机的,而从长期看则存在着一种“精致”地内在关系,由此获得了一系列基于混沌序列的遗传算法,这些算法对克服标准遗传算法中的一些不足是有利的,更重要是将混沌引入遗传算法的新思路。     

1‐Rotational Steiner triple systems over arbitrary groups

Phelps and Rosa introduced the concept of 1‐rotational Steiner triple system, that is an STS(ν) admitting an automorphism consisting of a fixed point and a single cycle of length ν ? 1 [Discrete Math. 33 ( 12 ), 57–66]. They proved that such an STS(ν) exists if and only if ν ≡ 3 or 9 (mod 24). Here, we speak of a 1‐rotational STS(ν) in a more general sense. An STS(ν) is 1‐rotational over a group G when it admits G as an automorphism group, fixing one point and acting regularly on the other points. Thus the STS(ν)'s by Phelps and Rosa are 1‐rotational over the cyclic group. We denote by ??_1r, ??_1r, ??_1r, ??_1r, the spectrum of values of ν for which there exists a 1‐rotational STS(ν) over an abelian, a cyclic, a dicyclic, and an arbitrary group, respectively. In this paper, we determine ??_1r and find partial answers about ??_1r and ??_1r. The smallest 1‐rotational STSs have orders 9, 19, 25 and are unique up to isomorphism. In particular, the only 1‐rotational STS(25) is over SL₂(3), the special linear group of dimension 2 over Z₃. © 2001 John Wiley & Sons, Inc. J Combin Designs 9: 215–226, 2001     

Some results for asymptotically pseudo-contractive mappings and asymptotically nonexpansive mappings

Some convergence theorems of modified Ishikawa and Mann iterative sequences with errors for asymptotically pseudo-contractive and asymptotically nonexpansive mappings in Banach space are obtained. The results presented in this paper improve and extend the corresponding results in Goebel and Kirk (1972), Kirk (1965), Liu (1996), Schu (1991) and Chang et al. (to appear).

     

关于零和子列个数的一个猜想

本文证明了下述结论: 设p>10000为一素数且合于p≡3(mod 4),取S=((?)2,3)为Z_p上p项序列,则不存在 Z_p上 p 项序列 T,使得f_p(S)=f_p(T)且T的非零项最多有两项互异,其中,f_p(S)表示S的零和子列的个数,这一结论否定了一个有关零和问题的猜想,     

三维七元线性码的重量谱与改进的遗传算法

[n,3,7]线性码的重量谱与其差序列是一一对应的。本文改进了[1]结构4的条件（iv),从而得到了不满足链条件的[n,3;7]线性码的差序列的充要条件,并应用改进的遗传算法搜索满足链条件的[n,3;7]线性码的差序列,取得了较好的结果。     

计算Bezout矩阵惯性的一个快速方法及其应用

本文给出了求Bezout矩阵的惯性的一个快速的无除方法,并且由此方法可很快得出一个整系数多项式方程的不同实根个数及不同对共轭复根的对数。     

孔石莼质体蓝素的柱色谱纯化及其N-端氨基酸序列的分析测定

通过DEAE-Sepharose Fast Flow阴离子交换柱和Sephadex G-75凝胶过滤柱分离纯化得到了孔石莼(Ulva pertusa)的质体蓝素。其步骤为:将孔石莼样品以0.02 mol/L磷酸盐缓冲液(pH 7.2)进行匀浆,然后离心去除沉淀,将上清液用硫酸铵分级盐析获得饱和度为40%~80%的盐析蛋白;通过DEAE-Sepharose 柱色谱,在含有0~1.0 mol/L NaCl 的0.01 mol/L磷酸盐缓冲液线性梯度洗脱下,盐析蛋白有3个主要的洗脱峰,然后在Sephadex G-75凝胶过滤色谱柱中进一步纯化。十二烷基硫酸钠-聚丙烯酰胺凝胶电泳（SDS-PAGE）显示,该蛋白质被纯化为单一条带。根据蛋白质电泳迁移率,纯化蛋白质的相对分子质量约为10000。该蛋白质不含糖。纯化的蛋白质经电转移至聚偏二氟乙烯（PVDF）膜后,以Edman降解法进行N-端氨基酸序列测定,前20个氨基酸残基序列为AAIVKLGPDDGSLAFVPSKI。通过对相关蛋白质数据库的检索,发现该序列与3种已报道的海藻的质体蓝素具有较高的序列同源性,其同源性分别为85%,85%和90%。据此,认为孔石莼的质体蓝素已获得纯化,其N-端20个氨基酸残基与已报道的海藻质体蓝素的氨基酸残基有较大的同源性,也存在着一定的变异。     

凸度量空间中拟压缩映象具误差的Ishikawa型迭代序列的收敛性

对凸度量空间中非线性拟压缩映象具误差的Ishikawa型迭代序列的收敛性问题证明了几个新的收敛性定理,结果不仅改进和推广了L.B.Ciric,Q.H.Liu,H.E.Rhoades,H.K.Xu等人的相应结果,而且对Rhoades-Naimplally-Singh所提出的公开问题,在凸度量空间的框架下给出了肯定的答复.     

Evolutionary Approach in Copolymer Sequence Design

Summary : In this work, we discuss a simple evolutionary algorithm that introduces a “selection pressure” under which two-letter (AB) copolymer sequences can mutate and transform into the sequences tuned to microphase separation transition (MIST). In particular, we are interested in determining how a sequence of A and B units should be organized in order to reach maximum length scale for MIST at a given AB composition. It is found that such sequences are similar to those known for tapered or gradient copolymers exhibiting strong composition inhomogeneity along their chain. The problems of the evolution of copolymer sequences are considered from the viewpoint of emerging of information complexity in the sequences in the course of this evolution.     

Dynamics analysis on neural firing patterns by symbolic approach

Neural firing patterns are investigated by using symbolic dynamics. Bifurcation behaviour of the Hindmarsh--Rose (HR) neuronal model is simulated with the external stimuli gradually decreasing, and various firing activities with different topological structures are orderly numbered. Through constructing first-return maps of interspike intervals, all firing patterns are described and identified by symbolic expressions. On the basis of ordering rules of symbolic sequences, the corresponding relation between parameters and firing patterns is established, which will be helpful for encoding neural information. Moreover, using the operation rule of $\ast$ product, generation mechanisms and intrinsic configurations of periodic patterns can be distinguished in detail. Results show that the symbolic approach is a powerful tool to study neural firing activities. In particular, such a coarse-grained way can be generalized in neural electrophysiological experiments to extract much valuable information from complicated experimental data.