Ikegami T, Hashimoto T
Graduate School of Arts and Sciences, University of Tokyo, Japan.
Artif Life. 1995 Spring;2(3):305-18. doi: 10.1162/artl.1995.2.3.305.
Self-reproduction via description is discussed in a network model of machines and description tapes. Tapes consist of bit strings, which encode the machines' function A tape is replicated when it is read by adequate machines. Generally, a machine rewrites a tape without doing correct replication. The variation in a reproduced tape is taken as mutation. Because this mutation is caused by a machine's program, we call it active mutation. Which machine is translated from a given tape is dependent on what kind of a machine reads the tape. External noise is introduced in a machine's reading process to make errors. A new reaction pathway is induced by external noise via a machine's error action. We find that the induced pathways will be mimicked deterministically in an emerging core structure. This core structure will remain stable after turning off external noise. Low external noise develops a core structure of a minimal self-replicative loop. When external noise is elevated, a more complex network evolves. Machines containing a complex core network, which has been bred in high external noise, will actively rewrite tapes rather than just replicate them. Self-replication not as an individual but as a network now becomes important.
在机器与描述磁带的网络模型中讨论了通过描述进行自我复制的问题。磁带由比特串组成，这些比特串对机器的功能进行编码。当磁带被合适的机器读取时，磁带会被复制。一般来说，机器在重写磁带时不会进行正确的复制。复制磁带中的变化被视为突变。由于这种突变是由机器的程序引起的，我们称之为主动突变。从给定磁带翻译出哪种机器取决于读取该磁带的机器类型。在机器的读取过程中引入外部噪声以产生错误。外部噪声通过机器的错误动作诱导出一条新的反应路径。我们发现，诱导出的路径将在一个新兴的核心结构中被确定性地模仿。关闭外部噪声后，这个核心结构将保持稳定。低外部噪声会形成一个最小自我复制循环的核心结构。当外部噪声升高时，会演化出一个更复杂的网络。在高外部噪声中培育出的包含复杂核心网络的机器，将积极地重写磁带而不仅仅是复制它们。现在，作为一个网络而非个体的自我复制变得很重要。
