 
Summary: OnLine Machine Covering
Yossi Azar 1 ,Leah Epstein 2
1 Dept. of Computer Science, TelAviv University. ???
2 Dept. of Computer Science, TelAviv University. y
Abstract. We consider the problem of scheduling a sequence of jobs to
m parallel machines as to maximize the minimum load over the machines.
This situation corresponds to a case that a system which consists of the
m machines is alive (i.e. productive) only when all the machines are alive,
and the system should be maintained alive as long as possible. It is well
known that any online deterministic algorithm for identical machines
has a competitive ratio of at least m and that greedy is an m competitive
algorithm. In contrast we design an online randomized algorithm which
is ~
O( p
m) competitive and a matching lower bound
of\Omega ( p
m) for any on
line randomized algorithm. In the case where the jobs are polynomially
related we design an optimal O(log m) competitive randomized algorithm
and a matching tight lower bound for any online randomized algorithm.
