Summary: Delayed Information and Action in On-Line
Most on-line analysis assumes that, at each time-step, all relevant in-
formation up to that time step is available and a decision has an immediate
e ect. In many on-line problems, however, the time relevant information
is available and the time a decision has an e ect may be decoupled. For
example, when making an investment, one might not have completely up-
to-date information on market prices. Similarly, a buy or sell order might
only be executed some time later in the future.
We introduce and explore natural delayed models for several well-
known on-line problems. Our analyses demonstrate the importance of
considering timeliness in determining the competitive ratio of an on-line
algorithm. For many problems, we demonstrate that there exist algo-
rithms with small competitive ratios even when large delays a ect the
timeliness of information and the e ect of decisions.