论文标题
通过非参数内核回归的任务相似性了解元学习
Task-similarity Aware Meta-learning through Nonparametric Kernel Regression
论文作者
论文摘要
本文研究了使用非参数内核回归来获得任务相似的元学习算法。我们的假设是,当可用任务受到限制并且可能包含离群/不同任务时,任务相似性有助于元学习。尽管现有的元学习方法隐式地假设任务是相似的,但通常不清楚如何在学习中量化和使用此任务相似之处。结果,大多数流行的金属学习方法不会积极地使用任务之间的相似性/差异,而是依靠大量任务的可用性来工作。我们的贡献是用于元学习的新型框架,该框架以内核和相关的元学习算法的形式明确使用任务相似。我们将特定于任务的参数建模为属于繁殖的内核空间,其中内核函数捕获了跨任务的相似性。所提出的算法迭代学习了一个元参数,该元参数用于为每个任务分配特定于任务的描述符。然后,将任务描述符用于通过内核函数量化任务相似性。我们展示了我们的方法如何从概念上概括地概括了模型 - 静态元学习(MAML)和元数据梯度下降(META-SGD)方法的流行元学习方法。回归任务的数值实验表明,即使在存在异常或不同任务的情况下,我们的算法也优于这些方法。这支持了我们的假设,即任务相似之处有助于改善任务有限和不利设置中的金属学习性能。
This paper investigates the use of nonparametric kernel-regression to obtain a tasksimilarity aware meta-learning algorithm. Our hypothesis is that the use of tasksimilarity helps meta-learning when the available tasks are limited and may contain outlier/ dissimilar tasks. While existing meta-learning approaches implicitly assume the tasks as being similar, it is generally unclear how this task-similarity could be quantified and used in the learning. As a result, most popular metalearning approaches do not actively use the similarity/dissimilarity between the tasks, but rely on availability of huge number of tasks for their working. Our contribution is a novel framework for meta-learning that explicitly uses task-similarity in the form of kernels and an associated meta-learning algorithm. We model the task-specific parameters to belong to a reproducing kernel Hilbert space where the kernel function captures the similarity across tasks. The proposed algorithm iteratively learns a meta-parameter which is used to assign a task-specific descriptor for every task. The task descriptors are then used to quantify the task-similarity through the kernel function. We show how our approach conceptually generalizes the popular meta-learning approaches of model-agnostic meta-learning (MAML) and Meta-stochastic gradient descent (Meta-SGD) approaches. Numerical experiments with regression tasks show that our algorithm outperforms these approaches when the number of tasks is limited, even in the presence of outlier or dissimilar tasks. This supports our hypothesis that task-similarity helps improve the metalearning performance in task-limited and adverse settings.