On the computational power of totalistic cellular automata

Totalistic cellular automata, introduced by S. Wolfram, are cellular automata in which the state transition function depends only on the sum of the states in a cell's neighborhood. Each state is considered as a nonnegative integer and the sum includes the cell's own state. It is shown that one-dimensional totalistic cellular automata can simulate an arbitrary Turing machine in linear time, even when the neighborhood is restricted to one cell on each side. This result settles Wolfram's conjecture that totalistic cellular automata are computation-universal.Research performed while visiting the Department of Computer Science, University of Cincinnati, 1984/85.     

Error correcting capability of cellular automata based associative memory

This paper reports the error correcting capability of an associative memory model built around the sparse network of cellular automata (CA). Analytical formulation supported by experimental results has demonstrated the capability of CA based sparse network to memorize unbiased patterns while accommodating noise. The desired CA are evolved with an efficient formulation of simulated annealing (SA) program. The simple, regular, modular, and cascadable structure of CA based associative memory suits ideally for design of low cost high speed online pattern recognizing machine with the currently available VLSI technology.     

数学软件Mathematica在化学反应工程中的应用

化学反应工程中会遇到大量复杂的数学模型求解和数学模型参数估值问题,以往依靠手工或编写计算机程序计算.本文采用数学软件Mathematica求解了若干化学反应工程中的数学问题,例如用FindRoot命令求取非理想反应器的轴向扩散模型中彼克列(Pe)准数,NonLinearFit命令进行反应动力学模型中的参数估值,符号计算和数值计算求反应器模拟中的定积分和微分方程的解.求解过程表明Mathematica强大的计算功能可以避免编程工作,且具有可视和图形化的特点,是求解化学反应工程中的数学问题的先进工具.     

The minimization of finite automata

Cybernetics and Systems Analysis -     

The cartesian composition of automata

There are several known ways to define a product automaton on the cartesian product of the state sets of two given automata. This paper introduces a new product called the cartesian composition and discusses how various properties of the product automaton depend on the corresponding properties of the factors. A main result is that any finite connected automaton has a unique representation as a cartesian composition of prime automata.     

计算流体力学在化学反应器模拟中的应用进展

计算流体力学(CFD)能够准确地描述流体流动、混合、传热规律,近年来逐渐开始耦合到化学反应中应用于化学工程领域,并表现出巨大潜力。本文综述了CFD在不同化学反应器中针对不同反应体系模拟的基本原理以及应用。相比于传统的面向理想反应器的反应动力学模拟和单纯面向流动传递的CFD模拟方法而言,采用CFD耦合化学反应动力学的方法同时考虑了传递过程和反应过程,能够对非理想化学反应器的操作特性(转化率、选择性、分子量及其分布等)进行模拟、分析与预测,在化工过程强化和化工产品控制方面优势明显。开发新的耦合数学模型和数值算法、考虑亚格子尺度的微观过程和采用直接数值模拟等方法,将是利用CFD深入研究非理想反应器特性的重要方向。     

A computer monitored chemical reaction

The instrumental set-up as well as the program structure is presented for a solution phase chemical reaction in process control. Educational applications are outlined for its use within a physical chemistry laboratory course. By means of this experiment students are introduced and acquainted with computerized instrumentations, data acquisition, data reduction, and process control.     

实值化学反应优化算法

化学反应优化（CRO）是近年来提出的一个基于种群的元启发式算法,而实数编码化学反应优化（RCCRO）是CRO的一个变体,针对该算法存在的不足提出了一个新的实值化学反应优化（RVCRO）算法求解全局数值优化问题。该算法改进了传统CRO的框架和搜索模式,将控制参数从8个减少到5个;采用一组常用的基准函数来测试其性能,比较结果表明,该算法在最终误差值和收敛速度方面,性能有较大提升。     

The ergodic theory of cellular automata

Ergodic theory is the study of how a dynamical system transforms the information encoded in an invariant probability measure. This article reviews the major recent results in the ergodic theory of cellular automata.     

A computational insight into cyclopropenone activated dehydration reaction of alcohols

The cyclopropenone activated dehydration reaction of alcohols is a promising alternative to alcohol substitution reactions to avoid hazardous byproducts and harsh reaction conditions. Density functional theory calculations at M062X/6–31 + G(d,p) level were performed for two proposed reaction mechanisms of the cyclopropenone activated chlorodehydration reaction where alkyl chloride product can be obtained from both of the proposed reaction mechanisms but chloroxalate has only one alternative. The calculations enabled us to explain the rection mechanisms in detail. Additionally, the effects of the various substituents on the cyclopropenone ring for the product distribution ratio was clarified.The substitution with electron donating group on para position of the phenyl ring of cyclopropenone has no effect on the relative free energy of the rate-determining step where the electron-withdrawing group increase the energy values independent from the position. The product ratio values that were calculated from energy barriers are in harmony with the experimentally obtained ones pointing out the reaction mechanism preference.     

虚拟现实技术在化学反应工程实验教学中的应用

将虚拟现实技术应用到化学反应工程实验教学中,能大大降低成本,同时也能满足实验教学中情景化及自然交互性的要求。本文概述虚拟现实及其实现技术,提出一种构建化学反应工程虚拟实验室的方案。     

Computational complexity of atomic chemical reaction networks

Chemical reaction network has been a model of interest to both theoretical and applied computer scientists, and there has been concern about its physical-realisticity which calls for study on the atomic property of chemical reaction networks. Informally, a chemical reaction network is “atomic” if each reaction may be interpreted as the rearrangement of indivisible units of matter. There are several reasonable definitions formalizing this idea. We investigate the computational complexity of deciding whether a given network is atomic according to each of these definitions. Primitive atomic, which requires each reaction to preserve the total number of atoms, is shown to be equivalent to mass conservation. Since it is known that it can be decided in polynomial time whether a given chemical reaction network is mass-conserving (Mayr and Weihmann, in: International conference on applications and theory of petri nets and concurrency, Springer, New York, 2014), the equivalence we show gives an efficient algorithm to decide primitive atomicity. Subset atomic further requires all atoms be species, so intuitively this type of network is endowed with a “better” property than primitive atomic (i.e. mass conserving) ones in the sense that the atoms are not just abstract indivisible units, but also actual participants of reactions. We show that deciding if a network is subset atomic is in \({\mathsf{NP}}\), and “whether a network is subset atomic with respect to a given atom set” is strongly \({\mathsf{NP}}\)-\({\mathsf {complete}}\). Reachably atomic, studied by Adleman et al. (On the mathematics of the law of mass action, Springer, Dordrecht, 2014.  https://doi.org/10.1007/978-94-017-9041-3_1), and Gopalkrishnan (2016), further requires that each species has a sequence of reactions splitting it into its constituent atoms. Using a combinatorial argument, we show that there is a polynomial-time algorithm to decide whether a given network is reachably atomic, improving upon the result of Adleman et al. that the problem is decidable. We show that the reachability problem for reachably atomic networks is \({\mathsf {PSPACE}}\)-\({\mathsf {complete}}\). Finally, we demonstrate equivalence relationships between our definitions and some cases of an existing definition of atomicity due to Gnacadja (J Math Chem 49(10):2137, 2011).     

The equivalence problem of multidimensional multitape automata

This article considers the equivalence problem of multitape automata with multidimensional tapes, where the motion of the heads is monotone in all directions (no backward motion). It is shown that this problem can be reduced to the equivalence problem of ordinary multitape automata. Some applications of the result are adduced.     

On the computational power of automata with time or space bounded by Ackermann's or superexponential functions

In this paper, we investigate the classes of the functions computed by automata introduced in [11] with time or space bounded by Ackermann's or superexponential functions.