Patent ID: 8676841

Claim:
A computer-readable non-transitory storage medium storing a plurality of instructions for controlling a processor to process a data stream of events being continuously received by the processor over time, the plurality of instructions comprising: instructions that cause the processor to receive a query for detecting recurrence of a non-occurrence of a first event within each of a series of multiple time periods, wherein the first time period in the series of multiple time periods starts upon occurrence of a second event, the query specifying (a) a pattern of symbols that are matched by occurrences of events in the data stream being continuously received by the processor over time, and (b) a time duration specifying a length of time for each of the time periods in the series of multiple time periods; instructions that cause the processor to generate a modified pattern based on the pattern of symbols; instructions that cause the processor to generate an automaton for the query based upon the modified pattern; and instructions that cause the processor to perform processing for detecting recurrence of non-occurrence of the first event within each time period of the series of multiple time periods following occurrence of the second event using the automaton by detecting a separate non-occurrence of the first event for each particular time period of the multiple time periods in which the first event does not occur, regardless of whether the second event re-occurs in that particular time period.