Archive image from page 249 of Design for a brain (1954). Design for a brain . designforbrain00ashb Year: 1954 22/2 DESIGN FOR A BRAIN Then if du/dt = <5{(w, v, . . .)}, du/dt will be usually zero ; but if the changes of w, v, . . . take through zero, then d(u) becomes momentarily infinite and n will change by a finite jump. These Figure 22/2/2 : Field of the 3-variable system. representations are of little practical use, but they are important theoretically in showing that a step-function can be represented in the canonical equations. 22/3. In an absolute system, a step-function will
Archive image from page 249 of Design for a brain (1954). Design for a brain . designforbrain00ashb Year: 1954 22/2 DESIGN FOR A BRAIN Then if du/dt = <5{(w, v, . . .)}, du/dt will be usually zero ; but if the changes of w, v, . . . take through zero, then d(u) becomes momentarily infinite and n will change by a finite jump. These Figure 22/2/2 : Field of the 3-variable system. representations are of little practical use, but they are important theoretically in showing that a step-function can be represented in the canonical equations. 22/3. In an absolute system, a step-function will change value if, and only if, the system arrives at certain states : the critical. In Figure 22/2/2, for instance, all the points in the plane k = K and to the right of the line xx = X are critical states for the step- function k when it has the initial value K. The critical states may, of course, be distributed arbitrarily. More commonly, however, the distribution is continuous. In this case there will be a critical surface (kt X{, . . . , Xn) = 0 which, given k, divides the critical from the non-critical states. In Figure 22/2/2, for instance, the surface intersects the plane k = K at the line x1 = X. (The plane k = 0 is not intersected by it, for there are no states in this system whose occurrence will result in k changing from 0.) Commonly <£ is a function of only a few of the variables of the 231
Size: 1647px × 1215px
Photo credit: © Actep Burstov / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: 1950, 1954, archive, ashby_william_ross, book, bookauthor, bookdecade, booksponsor, booksubject, bookyear, central_nervous_system_mathematical_models, drawing, historical, history, illustration, image, mblwhoi_library, neurophysiology, page, picture, print, reference, vintage
