Problem 3.6 (**). Let Q = {91.....9s) be a set of queries, A = {A1,...,As) be a set of attributes, and S = {S1,S2, S3} be a set of sites. The matrix of Figure 3.2la describes the attribute usage values and the matrix of Figure 3.2lb gives the applica- tion access frequencies. Assume that refi (9x) = 1 for all qk and S, and that A, is the key attribute. Use the bond energy and vertical partitioning algorithms to obtain a vertical fragmentation of the set of attributes in A. A 0 A 1 A 1 A 0 A 1 9 0 0 1 0 1 1 1 0 0 0 4 4 150 (a) Fig. 3.21 Attribute Usage Values and Application Access Frequencies in Exercise 3.6