(Technology to detect the Tumor cells)
TRIRUMALAI ENGINEERING COLLEGE,
There is broad agreement (though not consensus) that we will at some point in the future be able to inexpensively fabricate essentially any structure that is consistent with chemical and physical law and specified in molecular detail [REF04, REF06, REF07, REF08, REF18, REF21, REF22, REF30]. The most direct route to achieving this capability involves positioning and assembling individual atoms and molecules in a fashion conceptually similar to snapping together LEGO blocks. By designing and building programmable self-replicating manufacturing systems [REF10, REF18, REF30, REF27, REF28] that incorporate these principles we should be able to achieve very low manufacturing costs. While the design and development of such programmable self replicating molecular manufacturing systems will be a major task and will likely require many years or a few decades, it appears that this kind of capability, to quote Feynman [REF08], "...cannot be avoided."
Design concepts for general purpose self replicating manufacturing systems have been discussed for many years [REF10, REF27, REF28], and their utility in manufacturing has been emphasized recently [REF04, REF05, REF06, REF18, REF30]. These proposals draw on a body of work started by von Neumann [REF27]. The von Neumann architecture for a self-replicating system is the ancestral and archetypal proposal [REF24, REF27].
2. The von Neumann architecture for a general manufacturing system
Von Neumann's proposal consisted of two central elements: a universal computer and a universal constructor (see figure 1). The universal computer contains a program that directs the behavior of the universal constructor. The universal constructor, in turn, is used to manufacture both another universal computer and another universal constructor....