Semi-Supervised Learning (SSL) has received extensive attention in the domain of computer vision, leading to development of promising approaches such as FixMatch. In scenarios where training data is decentralized and resides on client devices, SSL must be integrated with privacy-aware training techniques such as Federated Learning. We consider the problem of federated image classification and study the performance and privacy challenges with existing federated SSL (FSSL) approaches. Firstly, we note that even state-of-the-art FSSL algorithms can trivially compromise client privacy and other real-world constraints such as client statelessness and communication cost. Secondly, we observe that it is challenging to integrate EMA (Exponential Moving Average) updates into the federated setting, which comes at a trade-off between performance and communication cost. We propose a novel approach FedSwitch, that improves privacy as well as generalization performance through Exponential Moving Average (EMA) updates. FedSwitch utilizes a federated semi-supervised teacher-student EMA framework with two features - local teacher adaptation and adaptive switching between teacher and student for pseudo-label generation. Our proposed approach outperforms the state-of-the-art on federated image classification, can be adapted to real-world constraints, and achieves good generalization performance with minimal communication cost overhead.

Many tasks aim to measure machine reading comprehension (MRC), often focusing on question types presumed to be difficult. Rarely, however, do task designers start by considering what systems should in fact comprehend. In this paper we make two key contributions. First, we argue that existing approaches do not adequately define comprehension; they are too unsystematic about what content is tested. Second, we present a detailed definition of comprehension -- a "Template of Understanding" -- for a widely useful class of texts, namely short narratives. We then conduct an experiment that strongly suggests existing systems are not up to the task of narrative understanding as we define it.

Despite studies showing collaboration to be beneficial both in terms of student satisfaction and learning, isolation is the norm in MOOCs. Two problems limiting the success of collaboration in MOOCs are the lack of support for team formation and structured collaboration support. Lack of support and strategies for team formation prevents teams from being set up for success from the beginning. Lack of structured support during synchronous collaboration has been demonstrated to produce significantly less learning than supported collaboration. This paper describes a deliberation based team formation approach and a scripted collaboration framework for MOOCs aimed at addressing these problems under the umbrella of Discussion Affordances for Natural Collaborative Exchange (DANCE) whose overarching focus is the enhancement of team-based MOOCs. These two examples of current work have been used as illustrations of insights informing interventions in MOOCs.