Chameleon: Learning Model Initializations Across Tasks With Different Schemas
Authors: Lukas Brinkmeyer, Rafael Rego Drumond, Randolf Scholz, Josif Grabocka, Lars Schmidt-Thieme
Keywords: Meta-Learning, Initialization, Few-shot classification
Abstract: Parametric models, and particularly neural networks, require weight initialization as a starting point for gradient-based optimization. Recent work shows that an initial parameter set can be learned from a population of supervised learning tasks that enables a fast convergence for unseen tasks even when only a handful of instances is available (model-agnostic meta-learning). 
Currently, methods for learning model initializations are limited to a population of tasks sharing the same schema, i.e., the same number, order, type, and semantics of predictor and target variables.
In this paper, we address the problem of meta-learning weight initialization across tasks with different schemas, for example, if the number of predictors varies across tasks, while they still share some variables. We propose Chameleon, a model that learns to align different predictor schemas to a common representation. 
In experiments on 23 datasets of the OpenML-CC18 benchmark, we show that Chameleon can successfully learn parameter initializations across tasks with different schemas, presenting, to the best of our knowledge, the first cross-dataset few-shot classification approach for unstructured data.