| The Role Hierarchy Mining Problem: Discovery of Optimal Role Hierarchies Recent countries visiting this post |  |
 | 5 | United States |
 | 3 | Korea, Republic of |
 | 1 | |
 | 1 | Germany |
| The Role Hierarchy Mining Problem: Discovery of Optimal Role Hierarchies Recent countries visiting this post | |
| 5 | United States |
| 3 | Korea, Republic of |
| 1 | |
| 1 | Germany |