1,796 research outputs found
Using Hindsight to Anchor Past Knowledge in Continual Learning
In continual learning, the learner faces a stream of data whose distribution
changes over time. Modern neural networks are known to suffer under this
setting, as they quickly forget previously acquired knowledge. To address such
catastrophic forgetting, many continual learning methods implement different
types of experience replay, re-learning on past data stored in a small buffer
known as episodic memory. In this work, we complement experience replay with a
new objective that we call anchoring, where the learner uses bilevel
optimization to update its knowledge on the current task, while keeping intact
the predictions on some anchor points of past tasks. These anchor points are
learned using gradient-based optimization to maximize forgetting, which is
approximated by fine-tuning the currently trained model on the episodic memory
of past tasks. Experiments on several supervised learning benchmarks for
continual learning demonstrate that our approach improves the standard
experience replay in terms of both accuracy and forgetting metrics and for
various sizes of episodic memories.Comment: Accepted at AAAI 202
Lifelong Learning of Spatiotemporal Representations with Dual-Memory Recurrent Self-Organization
Artificial autonomous agents and robots interacting in complex environments
are required to continually acquire and fine-tune knowledge over sustained
periods of time. The ability to learn from continuous streams of information is
referred to as lifelong learning and represents a long-standing challenge for
neural network models due to catastrophic forgetting. Computational models of
lifelong learning typically alleviate catastrophic forgetting in experimental
scenarios with given datasets of static images and limited complexity, thereby
differing significantly from the conditions artificial agents are exposed to.
In more natural settings, sequential information may become progressively
available over time and access to previous experience may be restricted. In
this paper, we propose a dual-memory self-organizing architecture for lifelong
learning scenarios. The architecture comprises two growing recurrent networks
with the complementary tasks of learning object instances (episodic memory) and
categories (semantic memory). Both growing networks can expand in response to
novel sensory experience: the episodic memory learns fine-grained
spatiotemporal representations of object instances in an unsupervised fashion
while the semantic memory uses task-relevant signals to regulate structural
plasticity levels and develop more compact representations from episodic
experience. For the consolidation of knowledge in the absence of external
sensory input, the episodic memory periodically replays trajectories of neural
reactivations. We evaluate the proposed model on the CORe50 benchmark dataset
for continuous object recognition, showing that we significantly outperform
current methods of lifelong learning in three different incremental learning
scenario
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