U.S.  Patent  Mar.20,2012  Sheet  2 of 6  US  8,138,330  B2  m  T- ■  (!)  - LI.  1789’617~  098"617~  o=Q  I~O  oi-<  b’\_  0  0  Ou  ~  z  N  0  1789’617~  098’617~  (J  ~  E  Cl.  I!)  O’>  ’<:I"  "’"""  ~  0  I!)  "’"""  I!)  "’"""  I!)  "’"""  E  Cl.  0  0  N  0  ’<:I"  0  CD  0  CX)  0  "’"""  0  N  "’"""  0  ’<:I"  "’"""  0  CD  "’"""  0  co  "’"""  0  N  CX)  >- r--:  0)  0) 