Topological conjugacy of constant length substitution dynamical systems

Primitive constant length substitutions generate minimal symbolic dynamical systems. In this article we present an algorithm which can produce the list of injective substitutions of the same length that generate topologically conjugate systems. We show that each conjugacy class contains infinitely many substitutions which are not injective. As examples, the Toeplitz conjugacy class contains three injective substitutions (two on two symbols and one on three symbols), and the length two Thue–Morse conjugacy class contains twelve substitutions, among which are two on six symbols. Together, they constitute a list of all primitive substitutions of length two with infinite minimal systems which are factors of the Thue–Morse system.     

二元DNA Hamming码的设计及分析

DNA计算作为一种新的计算模式,有着强大的计算能力。实验表明,有效的编码可以提高DNA计算的可靠性,从而保证DNA计算的成功率。二元Hamming码是一类达到Hamming界的好码,也是仅有的两类完全码中的一类。文中基于纠错码编码理论给出了二元DNA Hamming码的设计过程,并进一步分析了所设计的二元DNA Hamming码的性质及其优点。     

基于循环码的常重复合码的构造

研究给出了一类基于循环码的常重复合码的构造,并利用指数和计算其参数.与相关的常重复合码相比,该码具有更多的码字,且渐近性较好.     

Fast reused code tracing method based on simhash and inverted index

A novel method for fast and accurately tracing reused code was proposed. Based on simhash and inverted in-dex, the method can fast trace similar functions in massive code. First of all, a code database with three-level inverted in-dex structures was constructed. For the function to be traced, similar code blocks could be found quickly according to simhash value of the code block in the function code. Then the potential similar functions could be fast traced using in-verted index. Finally, really similar functions could be identified by comparing jump relationships of similar code blocks. Further, malware samples containing similar functions could be traced. The experimental results show that the method can quickly identify the functions inserted by compilers and the reused functions based on the code database under the premise of high accuracy and recall rate.     

Important unanswered questions—1970

This paper was given as the opening address at the 1970 Albany International Conference on Radiation Effects in Semiconductors, and it attempts to establish a general overview of the field by concentrating on recent research developments and important unanswered questions. The continuing importance of impurity-defect interactions, of microscopic defect identification, and of the necessity for more theoretical calculations are emphasized. The rapid development of the field of ion implantation and its close relationship with radiation effects studies are pointed out. It is predicted that research in compound semiconductors will increase rapidly with close beneficial interaction with ion implantation studies.     

An Alternative Way to Generalize the Pentagon

We introduce the concept of a pentagonal geometry as a generalization of the pentagon and the Desargues configuration, in the same vein that the generalized polygons share the fundamental properties of ordinary polygons. In short, a pentagonal geometry is a regular partial linear space in which for all points x, the points not collinear with the point x, form a line. We compute bounds on their parameters, give some constructions, obtain some nonexistence results for seemingly feasible parameters and suggest a cryptographic application related to identifying codes of partial linear spaces.     

影视节目中酸碱指示剂的应用与评价

将影视节目中酸碱指示剂的应用引入到化学教学中，让学生在娱乐中学习化学知识，创造一个有趣的学习情境，提高学生的学习兴趣。     

Stable local trace formula

Langlands program is the central concern of modern number theory. In general, we think that the main tool for studying this program is the trace formula. Arthur-Selberg’s trace formula is successful in solving the endoscopic case of Langlands program. Arthur stabilized the geometric side of the local trace formula in the general case, but did not stabilize the general spectral. This paper aims to solve the general case by different method in the Archimedean case, by directly stabilizing the spectral side of the local trace formula, and obtains the stable local trace formula.     

前缀码与极大前缀码的一种新刻画

在语言图Γ(X*)概念的基础上,用新引入的语言竹竿l(X*)和语言竹竿集L(X*)的概念形象地刻画了前缀码与极大前缀码:A是前缀码l(X*)∈L(X*),S_l_((X*))∩A或为单点集或为Φ;A是极大前缀码l(X*)∈L(X*),i)S_(l(X*))∩A或为单点集或为Φ.ii)S_(l(X*))∩A=Φ■u∈S_(l(X*)),■a∈A,ω∈X~+使a=uw.     

On the Hamming distances of repeated-root constacyclic codes of length 4ps

Let $p$ be an odd prime, $s$, $m$ be positive integers, $\gamma ,\lambda$ be nonzero elements of the finite field ${\mathbb{F}}_{p^m}$ such that ${\gamma }^{p^s}=\lambda$. In this paper, we show that, for any positive integer $\eta$, the Hamming distances of all repeated-root $\lambda$-constacyclic codes of length $\eta p^s$ can be determined by those of certain simple-root $\gamma$-constacyclic codes of length $\eta$. Using this result, Hamming distances of all constacyclic codes of length $4p^s$ are obtained. As an application, we identify all MDS $\lambda$-constacyclic codes of length $4p^s$.