Outcomes Prediction via Time Intervals Related Patterns

The increasing availability of multivariate temporal data in many domains, such as biomedical, security and more, provides exceptional opportunities for temporal knowledge discovery, classification and prediction, but also challenges. Temporal variables are often sparse and in many domains, such as in biomedical data, they have huge number of variables. In recent decades in the biomedical domain events, such as conditions, drugs and procedures, are stored as time intervals, which enables to discover Time Intervals Related Patterns (TIRPs) and use for classification or prediction. In this study we present a framework for outcome events prediction, called Maitreya, which includes an algorithm for TIRPs discovery called KarmaLegoD, designed to handle huge number of symbols. Three indexing strategies for pairs of symbolic time intervals are proposed and compared, showing that the use of FullyHashed indexing is only slightly slower but consumes minimal memory. We evaluated Maitreya on eight real datasets for the prediction of clinical procedures as outcome events. The use of TIRPs outperform the use of symbols, especially with horizontal support (number of instances) as TIRPs feature representation.