1. A user activity recognition apparatus, comprising: a collector configured to collect a frequency-domain signal for each user activity and to generate learning data based on the frequency-domain signal; an extractor configured to extract a user activity feature from the frequency-domain signal based on an activity feature extracting model, wherein the activity feature extracting model is learned based on the learning data from the collector; and a classifier configured to analyze the user activity feature to classify a user activity pattern based on an activity pattern classifying model and configured to transmit the classified user activity pattern to an application device.