A promising route to realizing a robust electronic nose is via a sensor array, comprised of multiple sensors, each harboring a distinct, [usually] cross-sensitive recognition element . Mimicking the mammalian olfactory system , a sensor array with diverse recognition elements produces a high-dimensional response vector containing information to distinguish many different gas compositions . (The sensor array response vector stacks features of the response of each sensor belonging to the array.) Typically, a supervised machine learning model is trained-using labeled data, i.e., example gas compositions paired with the sensor response vectors they produce-to predict the composition of the gas from the response vector of the sensor array .