Selecting and Generating Computational Meaning Representations for Short Texts

Language conveys meaning, so natural language processing (NLP) requires representations of meaning. This work addresses two broad questions: (1) What meaning representation should we use? and (2) How can we transform text to our chosen meaning representation? In the first part, we explore different meaning representations (MRs) of short texts, ranging from surface forms to deep-learning-based models. We show the advantages and disadvantages of a variety of MRs for summarization, paraphrase detection, and clustering. In the second part, we use SQL as a running example for an in-depth look at how we can parse text into our chosen MR. We examine the text-to-SQL problem from three perspectives—methodology, systems, and applications—and show how each contributes to a fuller understanding of the task.PHDComputer Science & EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttps://deepblue.lib.umich.edu/bitstream/2027.42/143967/1/cfdollak_1.pd

State-of-the-art generalisation research in NLP: a taxonomy and review

The ability to generalise well is one of the primary desiderata of natural language processing (NLP). Yet, what `good generalisation' entails and how it should be evaluated is not well understood, nor are there any common standards to evaluate it. In this paper, we aim to lay the ground-work to improve both of these issues. We present a taxonomy for characterising and understanding generalisation research in NLP, we use that taxonomy to present a comprehensive map of published generalisation studies, and we make recommendations for which areas might deserve attention in the future. Our taxonomy is based on an extensive literature review of generalisation research, and contains five axes along which studies can differ: their main motivation, the type of generalisation they aim to solve, the type of data shift they consider, the source by which this data shift is obtained, and the locus of the shift within the modelling pipeline. We use our taxonomy to classify over 400 previous papers that test generalisation, for a total of more than 600 individual experiments. Considering the results of this review, we present an in-depth analysis of the current state of generalisation research in NLP, and make recommendations for the future. Along with this paper, we release a webpage where the results of our review can be dynamically explored, and which we intend to up-date as new NLP generalisation studies are published. With this work, we aim to make steps towards making state-of-the-art generalisation testing the new status quo in NLP.Comment: 35 pages of content + 53 pages of reference

A Survey on LLM-generated Text Detection: Necessity, Methods, and Future Directions

The powerful ability to understand, follow, and generate complex language emerging from large language models (LLMs) makes LLM-generated text flood many areas of our daily lives at an incredible speed and is widely accepted by humans. As LLMs continue to expand, there is an imperative need to develop detectors that can detect LLM-generated text. This is crucial to mitigate potential misuse of LLMs and safeguard realms like artistic expression and social networks from harmful influence of LLM-generated content. The LLM-generated text detection aims to discern if a piece of text was produced by an LLM, which is essentially a binary classification task. The detector techniques have witnessed notable advancements recently, propelled by innovations in watermarking techniques, zero-shot methods, fine-turning LMs methods, adversarial learning methods, LLMs as detectors, and human-assisted methods. In this survey, we collate recent research breakthroughs in this area and underscore the pressing need to bolster detector research. We also delve into prevalent datasets, elucidating their limitations and developmental requirements. Furthermore, we analyze various LLM-generated text detection paradigms, shedding light on challenges like out-of-distribution problems, potential attacks, and data ambiguity. Conclusively, we highlight interesting directions for future research in LLM-generated text detection to advance the implementation of responsible artificial intelligence (AI). Our aim with this survey is to provide a clear and comprehensive introduction for newcomers while also offering seasoned researchers a valuable update in the field of LLM-generated text detection. The useful resources are publicly available at: https://github.com/NLP2CT/LLM-generated-Text-Detection

Enabling Structured Navigation of Longform Spoken Dialog with Automatic Summarization

Longform spoken dialog is a rich source of information that is present in all facets of everyday life, taking the form of podcasts, debates, and interviews; these mediums contain important topics ranging from healthcare and diversity to current events, economics and politics. Individuals need to digest informative content to know how to vote, decide how to stay safe from COVID-19, and how to increase diversity in the workplace. Unfortunately compared to text, spoken dialog can be challenging to consume as it is slower than reading and difficult to skim or navigate. Although an individual may be interested in a given topic, they may be unwilling to commit the required time necessary to consume long form auditory media given the uncertainty as to whether such content will live up to their expectations. Clearly, there exists a need to provide access to the information spoken dialog provides in a manner through which individuals can quickly and intuitively access areas of interest without investing large amounts of time. From Human Computer Interaction, we apply the idea of information foraging, which theorizes how people browse and navigate to satisfy an information need, to the longform spoken dialog domain. Information foraging states that people do not browse linearly. Rather people “forage” for information similar to how animals sniff around for food, scanning from area to area, constantly deciding whether to keep investigating their current area or to move on to greener pastures. This is an instance of the classic breadth vs. depth dilemma. People rely on perceived structure and information cues to make these decisions. Unfortunately speech, either spoken or transcribed, is unstructured and lacks information cues, making it difficult for users to browse and navigate. We create a longform spoken dialog browsing system that utilizes automatic summarization and speech modeling to structure longform dialog to present information in a manner that is both intuitive and flexible towards different user browsing needs. Leveraging summarization models to automatically and hierarchically structure spoken dialog, the system is able to distill information into increasingly salient and abstract summaries, allowing for a tiered representation that, if interested, users can progressively explore. Additionally, we address spoken dialog’s own set of technical challenges to speech modeling that are not present in written text, such as disfluencies, improper punctuation, lack of annotated speech data, and inherent lack of structure. We create a longform spoken dialog browsing system that utilizes automatic summarization and speech modeling to structure longform dialog to present information in a manner that is both intuitive and flexible towards different user browsing needs. Leveraging summarization models to automatically and hierarchically structure spoken dialog, the system is able to distill information into increasingly salient and abstract summaries, allowing for a tiered representation that, if interested, users can progressively explore. Additionally, we address spoken dialog’s own set of technical challenges to speech modeling that are not present in written text, such as disfluencies, improper punctuation, lack of annotated speech data, and inherent lack of structure. Since summarization is a lossy compression of information, the system provides users with information cues to signal how much additional information is contained on a topic. This thesis makes the following contributions: 1. We applied the HCI concept of information foraging to longform speech, enabling people to browse and navigate information in podcasts, interviews, panels, and meetings. 2. We created a system that structures longform dialog into hierarchical summaries which help users to 1) skim (browse) audio and 2) navigate and drill down into interesting sections to read full details. 3. We created a human annotated hierarchical dataset to quantitatively evaluate the effectiveness of our system’s hierarchical text generation performance. 4. Lastly, we developed a suite of dialog oriented processing optimizations to improve the user experience of summaries: enhanced readability and fluency of short summaries through better topic chunking and pronoun imputation, and reliable indication of semantic coverage within short summaries to help direct navigation towards interesting information. We discuss future research in extending the browsing and navigating system to more challenging domains such as lectures, which contain many external references, or workplace conversations, which contain uncontextualized background information and are far less structured than podcasts and interviews

Natural Language Processing: Emerging Neural Approaches and Applications

This Special Issue highlights the most recent research being carried out in the NLP field to discuss relative open issues, with a particular focus on both emerging approaches for language learning, understanding, production, and grounding interactively or autonomously from data in cognitive and neural systems, as well as on their potential or real applications in different domains

Backdoor Attacks and Countermeasures in Natural Language Processing Models: A Comprehensive Security Review

Deep Neural Networks (DNNs) have led to unprecedented progress in various natural language processing (NLP) tasks. Owing to limited data and computation resources, using third-party data and models has become a new paradigm for adapting various tasks. However, research shows that it has some potential security vulnerabilities because attackers can manipulate the training process and data source. Such a way can set specific triggers, making the model exhibit expected behaviors that have little inferior influence on the model's performance for primitive tasks, called backdoor attacks. Hence, it could have dire consequences, especially considering that the backdoor attack surfaces are broad. To get a precise grasp and understanding of this problem, a systematic and comprehensive review is required to confront various security challenges from different phases and attack purposes. Additionally, there is a dearth of analysis and comparison of the various emerging backdoor countermeasures in this situation. In this paper, we conduct a timely review of backdoor attacks and countermeasures to sound the red alarm for the NLP security community. According to the affected stage of the machine learning pipeline, the attack surfaces are recognized to be wide and then formalized into three categorizations: attacking pre-trained model with fine-tuning (APMF) or prompt-tuning (APMP), and attacking final model with training (AFMT), where AFMT can be subdivided into different attack aims. Thus, attacks under each categorization are combed. The countermeasures are categorized into two general classes: sample inspection and model inspection. Overall, the research on the defense side is far behind the attack side, and there is no single defense that can prevent all types of backdoor attacks. An attacker can intelligently bypass existing defenses with a more invisible attack. ......Comment: 24 pages, 4 figure