Tutorial Content
Introduction and Background
The initial segment addresses the foundational background and motivation for investigating CL for online behavioral analytics systems. We explore the general definition of the CL problem and its variants, then focus on key challenges such as catastrophic forgetting and scalability of LLMs for online behavior detection.
- Motivation for Continual Learning in social media contexts
- Definition of CL and problem variants (task-incremental, class-incremental, etc.)
- The stability-plasticity dilemma and catastrophic forgetting
- Applications: financial market analysis, crisis informatics (disaster response), cybersecurity (scam detection)
Experience-Replay-based Methods
Replay represents the most prevalent approach employed for CL across various problems and domains. It contributes to performance enhancement without requiring the entirety of previously trained datasets. This method consists of two components: a replay buffer and model adaptation.
- Exemplar Selection for Replay: Task-aware random selection; clustering-based approaches for diverse sample selection; influence-based selection
- Replay-based Model Adaptation: Data concatenation strategies; handling class imbalance; data regularization with loss constraints comparing replay data on current vs. previous model versions
Regularization-based Methods
Parameter regularization involves storing model parameters deemed important for prior tasks in a knowledge store, then utilizing that stored knowledge during current task learning as a regularizer — aiming to prevent overriding of weights critical to past tasks.
- Parameter Regularization: Importance-weighted parameter preservation; elastic weight consolidation and related techniques
- Feature (Function) Regularization: Constraining the feature space during new task learning to prevent divergence from features learned in prior tasks
Beyond Traditional Settings
The standard CL approach often assumes sufficient resources and independent data samples. However, online behavioral analytics presents unique challenges: data arrives in high-velocity bursty streams, and user behaviors are inherently sequential and context-dependent.
- Resource-Constrained Environments: Knowledge Distillation from continually updating teacher to lightweight student models; Parameter-Efficient Fine-Tuning (PEFT) with adapters
- Streaming Data Dynamics: Reservoir Sampling and its derivatives for minority-class representation without explicit task boundaries
Open Challenges and Future Directions
Continual fine-tuning of LLMs remains an open problem, as techniques such as regularization do not scale well with large numbers of parameters. This section surveys emerging research directions.
- Continual Learning with LLMs: Using large language models as teachers to train smaller, efficient models suited for deployment
- From Internal to External Knowledge: External knowledge integration for continual text classification; Retrieval-Augmented Generation (RAG) for dynamic data access; tool-based learning