656 research outputs found
Dynamic Graph Representation Learning for Video Dialog via Multi-Modal Shuffled Transformers
Given an input video, its associated audio, and a brief caption, the
audio-visual scene aware dialog (AVSD) task requires an agent to indulge in a
question-answer dialog with a human about the audio-visual content. This task
thus poses a challenging multi-modal representation learning and reasoning
scenario, advancements into which could influence several human-machine
interaction applications. To solve this task, we introduce a
semantics-controlled multi-modal shuffled Transformer reasoning framework,
consisting of a sequence of Transformer modules, each taking a modality as
input and producing representations conditioned on the input question. Our
proposed Transformer variant uses a shuffling scheme on their multi-head
outputs, demonstrating better regularization. To encode fine-grained visual
information, we present a novel dynamic scene graph representation learning
pipeline that consists of an intra-frame reasoning layer producing
spatio-semantic graph representations for every frame, and an inter-frame
aggregation module capturing temporal cues. Our entire pipeline is trained
end-to-end. We present experiments on the benchmark AVSD dataset, both on
answer generation and selection tasks. Our results demonstrate state-of-the-art
performances on all evaluation metrics.Comment: Accepted at AAAI 202
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Explainable and Advisable Learning for Self-driving Vehicles
Deep neural perception and control networks are likely to be a key component of self-driving vehicles. These models need to be explainable - they should provide easy-to-interpret rationales for their behavior - so that passengers, insurance companies, law enforcement, developers, etc., can understand what triggered a particular behavior. Explanations may be triggered by the neural controller, namely introspective explanations, or informed by the neural controller's output, namely rationalizations. Our work has focused on the challenge of generating introspective explanations of deep models for self-driving vehicles. In Chapter 3, we begin by exploring the use of visual explanations. These explanations take the form of real-time highlighted regions of an image that causally influence the network's output (steering control). In the first stage, we use a visual attention model to train a convolution network end-to-end from images to steering angle. The attention model highlights image regions that potentially influence the network's output. Some of these are true influences, but some are spurious. We then apply a causal filtering step to determine which input regions actually influence the output. This produces more succinct visual explanations and more accurately exposes the network's behavior. In Chapter 4, we add an attention-based video-to-text model to produce textual explanations of model actions, e.g. "the car slows down because the road is wet". The attention maps of controller and explanation model are aligned so that explanations are grounded in the parts of the scene that mattered to the controller. We explore two approaches to attention alignment, strong- and weak-alignment. These explainable systems represent an externalization of tacit knowledge. The network's opaque reasoning is simplified to a situation-specific dependence on a visible object in the image. This makes them brittle and potentially unsafe in situations that do not match training data. In Chapter 5, we propose to address this issue by augmenting training data with natural language advice from a human. Advice includes guidance about what to do and where to attend. We present the first step toward advice-giving, where we train an end-to-end vehicle controller that accepts advice. The controller adapts the way it attends to the scene (visual attention) and the control (steering and speed). Further, in Chapter 6, we propose a new approach that learns vehicle control with the help of long-term (global) human advice. Specifically, our system learns to summarize its visual observations in natural language, predict an appropriate action response (e.g. "I see a pedestrian crossing, so I stop"), and predict the controls, accordingly
A survey on knowledge-enhanced multimodal learning
Multimodal learning has been a field of increasing interest, aiming to
combine various modalities in a single joint representation. Especially in the
area of visiolinguistic (VL) learning multiple models and techniques have been
developed, targeting a variety of tasks that involve images and text. VL models
have reached unprecedented performances by extending the idea of Transformers,
so that both modalities can learn from each other. Massive pre-training
procedures enable VL models to acquire a certain level of real-world
understanding, although many gaps can be identified: the limited comprehension
of commonsense, factual, temporal and other everyday knowledge aspects
questions the extendability of VL tasks. Knowledge graphs and other knowledge
sources can fill those gaps by explicitly providing missing information,
unlocking novel capabilities of VL models. In the same time, knowledge graphs
enhance explainability, fairness and validity of decision making, issues of
outermost importance for such complex implementations. The current survey aims
to unify the fields of VL representation learning and knowledge graphs, and
provides a taxonomy and analysis of knowledge-enhanced VL models
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