2012.08.10 START � 3 B(3, 0.5) N = 8 3 2 1 0 1 3 3 1 wi, i = 1, 2, . . . , N i w 1 N 3 2 1 0 1 N �� 1(�) i wi, i = 1, 2, . . . , N wi > 0 wi = c log N i , i = 1, 2, . . . , N, c > 0 P[ [x, ∞) ] = 1 N �{i | wi � x} = 1 N �{i | i � Ne−x/c} ∼ e−x/c 1 N Xi wi x �� 2(�) Zipf Pareto wi = a � N i �1/b , i = 1, 2, . . . , N, a, b > 0 P[ [x, ∞) ] = 1 N �{i | wi � x} = �a x �b 1 N �� 3(�) wi = a � N i �1/b