28,939 research outputs found
Multi-Task Learning for Conversational Question Answering over a Large-Scale Knowledge Base
We consider the problem of conversational question answering over a
large-scale knowledge base. To handle huge entity vocabulary of a large-scale
knowledge base, recent neural semantic parsing based approaches usually
decompose the task into several subtasks and then solve them sequentially,
which leads to following issues: 1) errors in earlier subtasks will be
propagated and negatively affect downstream ones; and 2) each subtask cannot
naturally share supervision signals with others. To tackle these issues, we
propose an innovative multi-task learning framework where a pointer-equipped
semantic parsing model is designed to resolve coreference in conversations, and
naturally empower joint learning with a novel type-aware entity detection
model. The proposed framework thus enables shared supervisions and alleviates
the effect of error propagation. Experiments on a large-scale conversational
question answering dataset containing 1.6M question answering pairs over 12.8M
entities show that the proposed framework improves overall F1 score from 67% to
79% compared with previous state-of-the-art work
A Knowledge-Grounded Multimodal Search-Based Conversational Agent
Multimodal search-based dialogue is a challenging new task: It extends
visually grounded question answering systems into multi-turn conversations with
access to an external database. We address this new challenge by learning a
neural response generation system from the recently released Multimodal
Dialogue (MMD) dataset (Saha et al., 2017). We introduce a knowledge-grounded
multimodal conversational model where an encoded knowledge base (KB)
representation is appended to the decoder input. Our model substantially
outperforms strong baselines in terms of text-based similarity measures (over 9
BLEU points, 3 of which are solely due to the use of additional information
from the KB
Open-Retrieval Conversational Question Answering
Conversational search is one of the ultimate goals of information retrieval.
Recent research approaches conversational search by simplified settings of
response ranking and conversational question answering, where an answer is
either selected from a given candidate set or extracted from a given passage.
These simplifications neglect the fundamental role of retrieval in
conversational search. To address this limitation, we introduce an
open-retrieval conversational question answering (ORConvQA) setting, where we
learn to retrieve evidence from a large collection before extracting answers,
as a further step towards building functional conversational search systems. We
create a dataset, OR-QuAC, to facilitate research on ORConvQA. We build an
end-to-end system for ORConvQA, featuring a retriever, a reranker, and a reader
that are all based on Transformers. Our extensive experiments on OR-QuAC
demonstrate that a learnable retriever is crucial for ORConvQA. We further show
that our system can make a substantial improvement when we enable history
modeling in all system components. Moreover, we show that the reranker
component contributes to the model performance by providing a regularization
effect. Finally, further in-depth analyses are performed to provide new
insights into ORConvQA.Comment: Accepted to SIGIR'2
Look before you Hop: Conversational Question Answering over Knowledge Graphs Using Judicious Context Expansion
Fact-centric information needs are rarely one-shot; users typically ask follow-up questions to explore a topic. In such a conversational setting, the user's inputs are often incomplete, with entities or predicates left out, and ungrammatical phrases. This poses a huge challenge to question answering (QA) systems that typically rely on cues in full-fledged interrogative sentences. As a solution, we develop CONVEX: an unsupervised method that can answer incomplete questions over a knowledge graph (KG) by maintaining conversation context using entities and predicates seen so far and automatically inferring missing or ambiguous pieces for follow-up questions. The core of our method is a graph exploration algorithm that judiciously expands a frontier to find candidate answers for the current question. To evaluate CONVEX, we release ConvQuestions, a crowdsourced benchmark with 11,200 distinct conversations from five different domains. We show that CONVEX: (i) adds conversational support to any stand-alone QA system, and (ii) outperforms state-of-the-art baselines and question completion strategies
Survey on Evaluation Methods for Dialogue Systems
In this paper we survey the methods and concepts developed for the evaluation
of dialogue systems. Evaluation is a crucial part during the development
process. Often, dialogue systems are evaluated by means of human evaluations
and questionnaires. However, this tends to be very cost and time intensive.
Thus, much work has been put into finding methods, which allow to reduce the
involvement of human labour. In this survey, we present the main concepts and
methods. For this, we differentiate between the various classes of dialogue
systems (task-oriented dialogue systems, conversational dialogue systems, and
question-answering dialogue systems). We cover each class by introducing the
main technologies developed for the dialogue systems and then by presenting the
evaluation methods regarding this class
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