An instance of the compute engine 102, in the security network 106 or in a security agent 108, can perform comparisons, such as string match comparisons, value comparisons, hash comparisons, and/or other types of comparisons on event data 122 for one or more events, and produce new event data 122 based on results of the comparisons. For example, an instance of the compute engine 102 can process event data 122 in an event stream using refinements and/or compositions of a fundamental model according to instructions provided in a configuration 132. Refinement operations 202 and composition operations 302 that instances of the compute engine 102 can use are discussed below with respect to