A suite of technologies are helping taxonomists speed up species identification. Listen to more stories on the Noa app. Across a Swiss meadow and into its forested edges, the drone dragged a jumbo-size cotton swab from a 13-foot tether. Along its path, the moistened swab collected scraps of life: some combination of sloughed skin and hair; mucus, saliva, and blood splatters; pollen flecks and fungal spores. Later, biologists used a sequencer about the size of a phone to stream the landscape's DNA into code, revealing dozens upon dozens of species, some endangered, some invasive.

Domain adaptation aims to mitigate distribution shifts among different domains. However, traditional formulations are mostly limited to categorical domains, greatly simplifying nuanced domain relationships in the real world. In this work, we tackle a generalization with taxonomy-structured domains, which formalizes domains with nested, hierarchical similarity structures such as animal species and product catalogs. We build on the classic adversarial framework and introduce a novel taxonomist, which competes with the adversarial discriminator to preserve the taxonomy information. The equilibrium recovers the classic adversarial domain adaptation's solution if given a non-informative domain taxonomy (e.g., a flat taxonomy where all leaf nodes connect to the root node) while yielding non-trivial results with other taxonomies. Empirically, our method achieves state-of-the-art performance on both synthetic and real-world datasets with successful adaptation. Code is available at https://github.com/Wang-ML-Lab/TSDA.

As an ontologist, I'm often asked about the distinctions between taxonomies and ontologies, and whether ontologies are replacing taxonomies. The second question is easy to answer: "No." Both taxonomies and ontologies serve vital, and often complementary, roles ... if they are used right. A taxonomy is, to put it simply, a categorization scheme. Most readers should be familiar with a few critical taxonomies such as the Linnaeus Taxonomy used to represent how animals are related to one another, and the Dewey Decimal System for libraries, which represents subject areas of interest.