  A user can be represented as what he/she does along the history. A common way
to deal with the user modeling problem is to manually extract all kinds of
aggregated features over the heterogeneous behaviors, which may fail to fully
represent the data itself due to limited human instinct. Recent works usually
use RNN-based methods to give an overall embedding of a behavior sequence,
which then could be exploited by the downstream applications. However, this can
only preserve very limited information, or aggregated memories of a person.
When a downstream application requires to facilitate the modeled user features,
it may lose the integrity of the specific highly correlated behavior of the
user, and introduce noises derived from unrelated behaviors. This paper
proposes an attention based user behavior modeling framework called ATRank,
which we mainly use for recommendation tasks. Heterogeneous user behaviors are
considered in our model that we project all types of behaviors into multiple
latent semantic spaces, where influence can be made among the behaviors via
self-attention. Downstream applications then can use the user behavior vectors
via vanilla attention. Experiments show that ATRank can achieve better
performance and faster training process. We further explore ATRank to use one
unified model to predict different types of user behaviors at the same time,
showing a comparable performance with the highly optimized individual models.
