Abstract
Knowledge about the size of ring networks can be useful for problems in distributed systems. In this thesis, we propose a self-stabilizing algorithm for measuring the size of unidirectional rings. Our algorithm has two versions, one is randomized and the other deterministic. Both of them run under the synchronized distributed daemon. The system is semi-uniform. Each processor except the special node costs only constant memory space and the maximum stabilizing time for both of the two versions are O(n^3).