This primer is an attempt to provide a detailed summary of the different
facets of lifelong learning. We start with Chapter 2 which provides a
high-level overview of lifelong learning systems. In this chapter, we discuss
prominent scenarios in lifelong learning (Section 2.4), provide 8 Introduction
a high-level organization of different lifelong learning approaches (Section
2.5), enumerate the desiderata for an ideal lifelong learning system (Section
2.6), discuss how lifelong learning is related to other learning paradigms
(Section 2.7), describe common metrics used to evaluate lifelong learning
systems (Section 2.8). This chapter is more useful for readers who are new to
lifelong learning and want to get introduced to the field without focusing on
specific approaches or benchmarks. The remaining chapters focus on specific
aspects (either learning algorithms or benchmarks) and are more useful for
readers who are looking for specific approaches or benchmarks. Chapter 3
focuses on regularization-based approaches that do not assume access to any
data from previous tasks. Chapter 4 discusses memory-based approaches that
typically use a replay buffer or an episodic memory to save subset of data
across different tasks. Chapter 5 focuses on different architecture families
(and their instantiations) that have been proposed for training lifelong
learning systems. Following these different classes of learning algorithms, we
discuss the commonly used evaluation benchmarks and metrics for lifelong
learning (Chapter 6) and wrap up with a discussion of future challenges and
important research directions in Chapter 7.Comment: Lifelong Learning Prime