189 research outputs found
NLP-Based Techniques for Cyber Threat Intelligence
In the digital era, threat actors employ sophisticated techniques for which,
often, digital traces in the form of textual data are available. Cyber Threat
Intelligence~(CTI) is related to all the solutions inherent to data collection,
processing, and analysis useful to understand a threat actor's targets and
attack behavior. Currently, CTI is assuming an always more crucial role in
identifying and mitigating threats and enabling proactive defense strategies.
In this context, NLP, an artificial intelligence branch, has emerged as a
powerful tool for enhancing threat intelligence capabilities. This survey paper
provides a comprehensive overview of NLP-based techniques applied in the
context of threat intelligence. It begins by describing the foundational
definitions and principles of CTI as a major tool for safeguarding digital
assets. It then undertakes a thorough examination of NLP-based techniques for
CTI data crawling from Web sources, CTI data analysis, Relation Extraction from
cybersecurity data, CTI sharing and collaboration, and security threats of CTI.
Finally, the challenges and limitations of NLP in threat intelligence are
exhaustively examined, including data quality issues and ethical
considerations. This survey draws a complete framework and serves as a valuable
resource for security professionals and researchers seeking to understand the
state-of-the-art NLP-based threat intelligence techniques and their potential
impact on cybersecurity
Representation Learning for Words and Entities
This thesis presents new methods for unsupervised learning of distributed
representations of words and entities from text and knowledge bases. The first
algorithm presented in the thesis is a multi-view algorithm for learning
representations of words called Multiview Latent Semantic Analysis (MVLSA). By
incorporating up to 46 different types of co-occurrence statistics for the same
vocabulary of english words, I show that MVLSA outperforms other
state-of-the-art word embedding models. Next, I focus on learning entity
representations for search and recommendation and present the second method of
this thesis, Neural Variational Set Expansion (NVSE). NVSE is also an
unsupervised learning method, but it is based on the Variational Autoencoder
framework. Evaluations with human annotators show that NVSE can facilitate
better search and recommendation of information gathered from noisy, automatic
annotation of unstructured natural language corpora. Finally, I move from
unstructured data and focus on structured knowledge graphs. I present novel
approaches for learning embeddings of vertices and edges in a knowledge graph
that obey logical constraints.Comment: phd thesis, Machine Learning, Natural Language Processing,
Representation Learning, Knowledge Graphs, Entities, Word Embeddings, Entity
Embedding
A Survey on Deep Semi-supervised Learning
Deep semi-supervised learning is a fast-growing field with a range of
practical applications. This paper provides a comprehensive survey on both
fundamentals and recent advances in deep semi-supervised learning methods from
model design perspectives and unsupervised loss functions. We first present a
taxonomy for deep semi-supervised learning that categorizes existing methods,
including deep generative methods, consistency regularization methods,
graph-based methods, pseudo-labeling methods, and hybrid methods. Then we offer
a detailed comparison of these methods in terms of the type of losses,
contributions, and architecture differences. In addition to the past few years'
progress, we further discuss some shortcomings of existing methods and provide
some tentative heuristic solutions for solving these open problems.Comment: 24 pages, 6 figure
Relevance-Promoting Language Model for Short-Text Conversation
Despite the effectiveness of sequence-to-sequence framework on the task of
Short-Text Conversation (STC), the issue of under-exploitation of training data
(i.e., the supervision signals from query text is \textit{ignored}) still
remains unresolved. Also, the adopted \textit{maximization}-based decoding
strategies, inclined to generating the generic responses or responses with
repetition, are unsuited to the STC task. In this paper, we propose to
formulate the STC task as a language modeling problem and tailor-make a
training strategy to adapt a language model for response generation. To enhance
generation performance, we design a relevance-promoting transformer language
model, which performs additional supervised source attention after the
self-attention to increase the importance of informative query tokens in
calculating the token-level representation. The model further refines the query
representation with relevance clues inferred from its multiple references
during training. In testing, we adopt a
\textit{randomization-over-maximization} strategy to reduce the generation of
generic responses. Experimental results on a large Chinese STC dataset
demonstrate the superiority of the proposed model on relevance metrics and
diversity metrics.\footnote{Code available at
https://ai.tencent.com/ailab/nlp/dialogue/.Comment: AAAI 202
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Understanding Semantic Implicit Learning through distributional linguistic patterns: A computational perspective
The research presented in this PhD dissertation provides a computational perspective on Semantic Implicit Learning (SIL). It puts forward the idea that SIL does not depend on semantic knowledge as classically conceived but upon semantic-like knowledge gained through distributional analysis of massive linguistic input. Using methods borrowed from the machine learning and artificial intelligence literature, we construct computational models, which can simulate the performance observed during behavioural tasks of semantic implicit learning in a human-like way. We link this methodology to the current literature on implicit learning, arguing that this behaviour is a necessary by-product of efficient language processing.
Chapter 1 introduces the computational problem posed by implicit learning in general, and semantic implicit learning, in particular, as well as the computational framework, used to tackle them.
Chapter 2 introduces distributional semantics models as a way to learn semantic-like representations from exposure to linguistic input.
Chapter 3 reports two studies on large datasets of semantic priming which seek to identify the computational model of semantic knowledge that best fits the data under conditions that resemble SIL tasks. We find that a model which acquires semantic-like knowledge gained through distributional analysis of massive linguistic input provides the best fit to the data.
Chapter 4 generalises the results of the previous two studies by looking at the performance of the same models in languages other than English.
Chapter 5 applies the results of the two previous Chapters on eight datasets of semantic implicit learning. Crucially, these datasets use various semantic manipulations and speakers of different L1s enabling us to test the predictions of different models of semantics.
Chapter 6 examines more closely two assumptions which we have taken for granted throughout this thesis. Firstly, we test whether a simpler model based on phonological information can explain the generalisation patterns observed in the tasks. Secondly, we examine whether our definition of the computational problem in Chapter 5 is reasonable.
Chapter 7 summarises and discusses the implications for implicit language learning and computational models of cognition. Furthermore, we offer one more study that seeks to bridge the literature on distributional models of semantics to `deeper' models of semantics by learning semantic relations.
There are two main contributions of this dissertation to the general field of implicit learning research. Firstly, we highlight the superiority of distributional models of semantics in modelling unconscious semantic knowledge. Secondly, we question whether `deep' semantic knowledge is needed to achieve above chance performance in SIIL tasks. We show how a simple model that learns through distributional analysis of the patterns found in the linguistic input can match the behavioural results in different languages. Furthermore, we link these models to more general problems faced in psycholinguistics such as language processing and learning of semantic relations.Alexandros Onassis Foundatio
Representation Learning for Words and Entities
This thesis presents new methods for unsupervised learning of distributed representations of words and entities from text and knowledge bases. The first algorithm presented in the thesis is a multi-view algorithm for learning representations of words called Multiview LSA (MVLSA). Through experiments on close to 50 different views, I show that MVLSA outperforms other state-of-the-art word embedding models. After that, I focus on learning entity representations for search and recommendation and present the second algorithm of this thesis called Neural Variational Set Expansion (NVSE). NVSE is also an unsupervised learning method, but it is based on the Variational Autoencoder framework. Evaluations with human annotators show that NVSE can facilitate better search and recommendation of information gathered from noisy, automatic annotation of unstructured natural language corpora. Finally, I move from unstructured data and focus on structured knowledge graphs. Moreover, I present novel approaches for learning embeddings of vertices and edges in a knowledge graph that obey logical constraints
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