The ongoing pandemic has heightened the need for developing tools to flag COVID-19related misinformation on the internet, specifically on social media such as Twitter. However, due to novel language and the rapid change of information, existing misinformation detection datasets are not effective for evaluating systems designed to detect misinformation on this topic. Misinformation detection can be divided into two sub-tasks: (i) retrieval of misconceptions relevant to posts being checked for veracity, and (ii) stance detection to identify whether the posts Agree, Disagree, or express No Stance towards the retrieved misconceptions. To facilitate research on this task, we release COVIDLIES 1 , a dataset of 6761 expert-annotated tweets to evaluate the performance of misinformation detection systems on 86 different pieces of COVID-19 related misinformation. We evaluate existing NLP systems on this dataset, providing initial benchmarks and identifying key challenges for future models to improve upon. * First four authors contributed equally. 1 https://ucinlp.github.io/covid19 Tweet: "Coronavirus CV19 was a top secret biological warfare experiment. That is why it is only affecting the poor." Misconception: "Coronavirus is genetically engineered." Label: Agree Tweet: "It looks like we are all going to have to wait much longer for a #COVID19 vaccine." Misconception: "We're very close to a vaccine." Label: Disagree Tweet: "CDC: Coronavirus spreads rapidly in dense populations with public transit and regular social gatherings." Misconception: "Coronavirus cannot live in warm and tropical temperatures." Label: No Stance

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As the complexity of Deep Neural Network (DNN) models increases, their deployment on mobile devices becomes increasingly challenging, especially in complex vision tasks such as image classification. Many of recent contributions aim either to produce compact models matching the limited computing capabilities of mobile devices or to offload the execution of such burdensome models to a compute-capable device at the network edge-the edge servers. In this paper, we propose to modify the structure and training process of DNN models for complex image classification tasks to achieve in-network compression in the early network layers. Our training process stems from knowledge distillation, a technique that has been traditionally used to build small-student-models mimicking the output of larger-teacher-models. Here, we adopt this idea to obtain aggressive compression while preserving accuracy. Our results demonstrate that our approach is effective for state-of-the-art models trained over complex datasets, and can extend the parameter region in which edge computing is a viable and advantageous option. Additionally, we demonstrate that in many settings of practical interest we reduce the inference time with respect to specialized models such as MobileNet v2 executed at the mobile device, while improving accuracy.

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IR-based Question Answering (QA) systems typically use a sentence selector to extract the answer from retrieved documents. Recent studies have shown that powerful neural models based on the Transformer can provide an accurate solution to Answer Sentence Selection (AS2). Unfortunately, their computation cost prevents their use in real-world applications. In this paper, we show that standard and efficient neural rerankers can be used to reduce the amount of sentence candidates fed to Transformer models without hurting Accuracy, thus improving efficiency up to four times. This is an important finding as the internal representation of shallower neural models is dramatically different from the one used by a Transformer model, e.g., word vs. contextual embeddings. CCS CONCEPTS • Information systems → Retrieval models and ranking; Question answering.