Iterative Conversational Query Reformulation with Retrieval Guidance

Основные понятия

IterCQR iteratively trains a conversational query reformulation model without human-annotated rewrites, utilizing retrieval signals as a reward to generate queries optimized for off-the-shelf retrievers.

Аннотация

The paper proposes IterCQR, a methodology for iteratively training a conversational query reformulation (CQR) model without relying on human-annotated rewrites. The key insights are:

IterCQR initializes the CQR model using queries rewritten by a large language model (LLM), then iteratively trains the model by generating candidate queries and optimizing them using retrieval signals as a reward.

The iterative training process consists of two steps: exploration using Minimum Bayes Risk (MBR) training, and exploitation using Top-1 candidate selection. The MBR training leverages the cosine similarity between candidate queries and ground-truth passages as the reward, guiding the model to generate retriever-friendly queries.

IterCQR achieves state-of-the-art performance on two widely used conversational search datasets, TopiOCQA and QReCC, outperforming strong baselines that rely on human-annotated rewrites.

The paper also demonstrates IterCQR's superior performance in challenging scenarios, such as generalization to unseen datasets and low-resource settings, without requiring additional human annotations.

Through quantitative analysis, the authors show that as the iterations progress, IterCQR generates queries that increasingly summarize the previous dialogue context, leading to improved retrieval performance.

Статистика

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Цитаты

"Conversational search aims to retrieve passages containing essential information to answer queries in a multi-turn conversation."
"Owing to the conversational setting, queries in CQA suffer from a high dependency on the previous conversation context, as shown in Figure 1, introducing challenges such as omissions, ambiguity, and coreference."
"To address these challenges, we propose Iterative Conversational Query Reformulation (IterCQR), a methodology that conducts query reformulation without relying on human rewrites."

Ключевые выводы из

IterCQR

by Yunah Jang,K... в arxiv.org 04-09-2024

https://arxiv.org/pdf/2311.09820.pdf

Дополнительные вопросы

How can IterCQR be extended to handle more complex dialogue contexts, such as those involving multiple speakers or topic shifts?

IterCQR can be extended to handle more complex dialogue contexts by incorporating additional contextual information and features into the training process. Here are some ways to enhance IterCQR for handling complex dialogue contexts:

Speaker Identification: Integrate speaker identification mechanisms to differentiate between multiple speakers in the conversation. By identifying speakers, the model can tailor the query reformulation based on individual speaking styles, preferences, and information.

Topic Modeling: Implement topic modeling techniques to detect topic shifts within the dialogue. By understanding the transitions between topics, IterCQR can adjust the query reformulation strategy to maintain relevance and coherence.

Coreference Resolution: Enhance the model with coreference resolution capabilities to track references to entities or concepts across different turns. Resolving coreferences ensures that the reformulated queries accurately capture the intended meaning.

Contextual Embeddings: Utilize contextual embeddings such as BERT or RoBERTa to capture nuanced contextual information and dependencies within the dialogue. These embeddings can help the model better understand the context and generate more contextually relevant queries.

Multi-turn Context Modeling: Develop mechanisms to model multi-turn context effectively, considering the entire conversation history rather than just the immediate context. This can involve memory-augmented architectures or hierarchical modeling to capture long-range dependencies.

By incorporating these enhancements, IterCQR can adapt to more intricate dialogue contexts involving multiple speakers, topic shifts, and complex conversational dynamics.

How can the potential limitations of using retrieval signals as the sole reward for training the CQR model be addressed, and what are these limitations?

Using retrieval signals as the sole reward for training the CQR model may have some limitations that need to be addressed:
Limitations:

Sparse Reward Signal: Retrieval signals may not provide fine-grained feedback on the quality of the reformulated queries, leading to challenges in optimizing the model effectively.

Limited Diversity: Relying solely on retrieval signals may result in the model generating repetitive or generic queries that align well with the retrieval signal but lack diversity and creativity.

Overfitting to Retrieval Model: The CQR model may become overly specialized to the specific retrieval model used during training, limiting its generalizability to other retrieval systems.

Addressing Limitations:

Reward Augmentation: Incorporate additional reward signals, such as human feedback or diversity metrics, to provide a more comprehensive and informative signal for training the CQR model.

Adversarial Training: Introduce adversarial training techniques to encourage the generation of diverse and informative queries that challenge the retrieval model's limitations.

Curriculum Learning: Implement curriculum learning strategies to gradually expose the model to more complex retrieval scenarios, helping it learn from a variety of retrieval signals.

Transfer Learning: Pretrain the CQR model on a diverse dataset with varied retrieval signals before fine-tuning it on the specific retrieval task. This can help the model capture a broader range of query reformulation patterns.

By addressing these limitations through a combination of techniques, the CQR model can overcome the challenges associated with using retrieval signals as the sole reward and achieve more robust and effective query reformulation.

How might the IterCQR approach be applied to other natural language generation tasks that require optimizing for downstream performance, beyond just conversational search?

The IterCQR approach can be adapted and applied to various natural language generation tasks that require optimizing for downstream performance. Here are some ways in which IterCQR principles can be extended to other tasks:

Text Summarization: In text summarization tasks, IterCQR can be used to iteratively refine and enhance the summary generation process by leveraging retrieval signals to ensure the generated summaries capture the essential information from the source text.

Question Answering: For question answering systems, IterCQR can help in reformulating queries to improve the retrieval of relevant answers. By iteratively training the model with retrieval signals, it can generate more effective queries for retrieving accurate answers.

Document Generation: In tasks involving document generation, IterCQR can assist in generating coherent and informative documents by iteratively refining the content based on retrieval signals to ensure relevance and completeness.

Sentiment Analysis: For sentiment analysis tasks, IterCQR can be used to generate queries or prompts that capture the sentiment of the text effectively, leading to improved sentiment classification performance.

Machine Translation: In machine translation, IterCQR can aid in generating contextually relevant translations by iteratively refining the translation output based on retrieval signals from parallel corpora or reference translations.

By applying the principles of IterCQR to these tasks, it is possible to enhance the quality and effectiveness of natural language generation models across a wide range of applications, ultimately improving downstream performance and user experience.