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Bibliographic Details
Main Authors: Nejadasl, Fatemeh Karimi, Shamoun-Baranes, Judy, Rakhimberdiev, Eldar
Format: Preprint
Published: 2026
Subjects:
Online Access:https://arxiv.org/abs/2602.02618
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author Nejadasl, Fatemeh Karimi
Shamoun-Baranes, Judy
Rakhimberdiev, Eldar
author_facet Nejadasl, Fatemeh Karimi
Shamoun-Baranes, Judy
Rakhimberdiev, Eldar
contents Learning behavioral taxonomies from animal-borne sensors is challenging because labels are scarce, classes are highly imbalanced, and behaviors may be absent from the annotated set. We study generalized behavior discovery in short multivariate motion snippets from gulls, where each sample is a sequence with 3-axis IMU acceleration (20 Hz) and GPS speed, spanning nine expert-annotated behavior categories. We propose a semi-supervised discovery pipeline that (i) learns an embedding function from the labeled subset, (ii) performs label-guided clustering over embeddings of both labeled and unlabeled samples to form candidate behavior groups, and (iii) decides whether a discovered group is truly novel using a containment score. Our key contribution is a KDE + HDR (highest-density region) containment score that measures how much a discovered cluster distribution is contained within, or contains, each known-class distribution; the best-match containment score serves as an interpretable novelty statistic. In experiments where an entire behavior is withheld from supervision and appears only in the unlabeled pool, the method recovers a distinct cluster and the containment score flags novelty via low overlap, while a negative-control setting with no novel behavior yields consistently higher overlaps. These results suggest that HDR-based containment provides a practical, quantitative test for generalized class discovery in ecological motion time series under limited annotation and severe class imbalance.
format Preprint
id arxiv_https___arxiv_org_abs_2602_02618
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle A Semi-Supervised Pipeline for Generalized Behavior Discovery from Animal-Borne Motion Time Series
Nejadasl, Fatemeh Karimi
Shamoun-Baranes, Judy
Rakhimberdiev, Eldar
Machine Learning
Artificial Intelligence
Learning behavioral taxonomies from animal-borne sensors is challenging because labels are scarce, classes are highly imbalanced, and behaviors may be absent from the annotated set. We study generalized behavior discovery in short multivariate motion snippets from gulls, where each sample is a sequence with 3-axis IMU acceleration (20 Hz) and GPS speed, spanning nine expert-annotated behavior categories. We propose a semi-supervised discovery pipeline that (i) learns an embedding function from the labeled subset, (ii) performs label-guided clustering over embeddings of both labeled and unlabeled samples to form candidate behavior groups, and (iii) decides whether a discovered group is truly novel using a containment score. Our key contribution is a KDE + HDR (highest-density region) containment score that measures how much a discovered cluster distribution is contained within, or contains, each known-class distribution; the best-match containment score serves as an interpretable novelty statistic. In experiments where an entire behavior is withheld from supervision and appears only in the unlabeled pool, the method recovers a distinct cluster and the containment score flags novelty via low overlap, while a negative-control setting with no novel behavior yields consistently higher overlaps. These results suggest that HDR-based containment provides a practical, quantitative test for generalized class discovery in ecological motion time series under limited annotation and severe class imbalance.
title A Semi-Supervised Pipeline for Generalized Behavior Discovery from Animal-Borne Motion Time Series
topic Machine Learning
Artificial Intelligence
url https://arxiv.org/abs/2602.02618