English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

This paper describes an artificial chemistry featuring atoms and molecules moving and colli ding in a continuous manner in a viscous fluid filli ng a 2D cellular space. Chemical reactions are mappings of discrete cellular configurations to parameterized actions on atoms. Actions allow atom creation and destruction, bonding and unbonding to make and break molecules, orientation, type change, and propulsion. Actions are easil y added in this extensible model. An example involving a complex “ foraging” reaction is provided as a demonstration of the capabiliti es of the framework. The reaction rules can be evolved by a genetic algorithm to exhibit a desired set of reactions. A portion of the foraging reaction was evolved to demonstrate this. Introduction This work was done in the spirit of the growing belief that artificial li fe requires a suff iciently rich physics and chemistry in which to develop (Bedau et al. 2000, Dittrich et al. 2001). The attempt here is to combine a simple continuous Newtonian particle physics with the well known and readily computable cellular automaton (CA) model as a chemistry implementation. There are two additional purposes for using a CA: (1) the chemistry of real organic molecules, involving complex foldings and bondings, is computationally infeasible (Zagrovic et al. 2002); and (2) it serves the aim of artificial li fe research to discover underlying mechanisms necessary for the existence of li ving systems. This project was primaril y inspired by three recent efforts: Hutton’s artificial chemistry Squirm3 (2002), Smith, Turney and Ewaschuk’s JohnnyVon (2003), and my prior work on intercellular signaling (Portegys 2002). Prior to these, Dittrich et al. (2001) compared a wide range of artificial chemistry approaches, including assembler automata (Rasmussen et al. 1990, Ray 1992, Adami and Brown 1994), Ono and Ikegami’s autocatalytic membrane formation (1999), and lattice molecular systems (McMulli n and Varela 1997), in which the atoms comprising a molecule map discretely to cellular space. Squirm3 is a lattice molecular system in which mobile molecules self-repli cate using available atoms in a 2D cellular space. Atoms have a fixed type and a variable state. Chemical reaction rules based on type, state and proximity determine the states and bonding status of atoms. Atoms move by jumping from cell to cell through simulated Brownian motion; however, atoms bound into molecules are largely immobile. Beginning with a soup of inert atoms exposed to state-disrupting cosmic rays, selfrepli cation was shown to spontaneously occur. In JohnnyVon, by contrast, T-shaped atoms called codons move through a continuous 2D space and interact exclusively through force fields; colli sions do not occur. There are two types of codons, distinguished by their field “colors” . Each codon is an automaton containing a set of rules governing its field strengths in response to signals represented by the proximity of other codon fields. This project uses the intercellular signaling scheme put forth in my recent work addressing the problem of allowing cell s in a CA to communicate without disturbing the state of intervening cell s. In this project, signals are chiefly directed toward atoms residing within cell s, rather than the cell s themselves. Description This system is an artificial chemistry featuring atoms and molecules moving and colli ding in a continuous manner in a viscous fluid filli ng a 2D cellular space. A molecule consists of a bound set of atoms. Chemical reactions are mappings of discrete cellular configurations to parameterized actions on atoms. Actions allow atom creation and destruction, bonding and unbonding to make and break molecules, orientation, type change, and propulsion. Time proceeds in discrete steps.

An Evolvable Artificial Chemistry Featuring Continuous Physics and Discrete Reactions