121 research outputs found
Integration of Computer Vision and Natural Language Processing in Multimedia Robotics Application
Computer vision and natural language processing (NLP) are two active machine learning research areas. However, the integration of these two areas gives rise to a new interdisciplinary field, which is currently attracting more attention of researchers. Research has been carried out to extract the text associated with an image or a video that can assist in making computer vision effective. Moreover, researchers focus on utilizing NLP to extract the meaning of words through the use of computer vision. This concept is widely used in robotics. Although robots should observe the surroundings from different ways of interactions, natural gestures and spoken languages are the most convenient way for humans to interact with the robots. This would be possible only if the robots can understand such types of interactions. In the present paper, the proposed integrated application is utilized for guiding vision-impaired people. As vision is the most essential in the life of a human being, an alternative source that helps in guiding the blind in their movements is highly important. For this purpose, the current paper uses a smartphone with the capabilities of vision, language, and intelligence which has been attached to the blind person to capture the images of their surroundings, and it is associated with a Faster Region Convolutional Neural Network (F-RCNN) based central server to detect the objects in the image to inform the person about them and avoid obstacles in their way. These results are passed to the smartphone which produces a speech output for the guidance of the blinds
Compositional Distributional Semantics with Compact Closed Categories and Frobenius Algebras
This thesis contributes to ongoing research related to the categorical
compositional model for natural language of Coecke, Sadrzadeh and Clark in
three ways: Firstly, I propose a concrete instantiation of the abstract
framework based on Frobenius algebras (joint work with Sadrzadeh). The theory
improves shortcomings of previous proposals, extends the coverage of the
language, and is supported by experimental work that improves existing results.
The proposed framework describes a new class of compositional models that find
intuitive interpretations for a number of linguistic phenomena. Secondly, I
propose and evaluate in practice a new compositional methodology which
explicitly deals with the different levels of lexical ambiguity (joint work
with Pulman). A concrete algorithm is presented, based on the separation of
vector disambiguation from composition in an explicit prior step. Extensive
experimental work shows that the proposed methodology indeed results in more
accurate composite representations for the framework of Coecke et al. in
particular and every other class of compositional models in general. As a last
contribution, I formalize the explicit treatment of lexical ambiguity in the
context of the categorical framework by resorting to categorical quantum
mechanics (joint work with Coecke). In the proposed extension, the concept of a
distributional vector is replaced with that of a density matrix, which
compactly represents a probability distribution over the potential different
meanings of the specific word. Composition takes the form of quantum
measurements, leading to interesting analogies between quantum physics and
linguistics.Comment: Ph.D. Dissertation, University of Oxfor
Exploiting word embeddings for modeling bilexical relations
There has been an exponential surge of text data in the recent years. As a consequence, unsupervised methods that make use of this data have been steadily growing in the field of natural language processing (NLP). Word embeddings are low-dimensional vectors obtained using unsupervised techniques on the large unlabelled corpora, where words from the vocabulary are mapped to vectors of real numbers. Word embeddings aim to capture syntactic and semantic properties of words.
In NLP, many tasks involve computing the compatibility between lexical items under some linguistic relation. We call this type of relation a bilexical relation. Our thesis defines statistical models for bilexical relations
that centrally make use of word embeddings. Our principle aim is that the word embeddings will favor generalization to words not seen during the training of the model.
The thesis is structured in four parts. In the first part of this thesis, we present a bilinear model over word embeddings that leverages a small supervised dataset for a binary linguistic relation. Our learning algorithm exploits low-rank bilinear forms and induces a low-dimensional embedding tailored for a target linguistic relation. This results in compressed task-specific embeddings.
In the second part of our thesis, we extend our bilinear model to a ternary
setting and propose a framework for resolving prepositional phrase attachment ambiguity using word embeddings. Our models perform competitively with state-of-the-art models. In addition, our method obtains significant improvements on out-of-domain tests by simply using word-embeddings induced from source and target domains.
In the third part of this thesis, we further extend the bilinear models for expanding vocabulary in the context of statistical phrase-based machine translation. Our model obtains a probabilistic list of possible translations of target language words, given a word in the source language. We do this by projecting pre-trained embeddings into a common subspace using a log-bilinear model. We empirically notice a significant improvement on an out-of-domain test set.
In the final part of our thesis, we propose a non-linear model that maps initial word embeddings to task-tuned word embeddings, in the context of a neural network dependency parser. We demonstrate its use for improved dependency parsing, especially for sentences with unseen words. We also show downstream improvements on a sentiment analysis task.En els darrers anys hi ha hagut un sorgiment notable de dades en format textual. Conseqüentment, en el camp del Processament del Llenguatge Natural (NLP, de l'anglès "Natural Language Processing") s'han desenvolupat mètodes no supervistats que fan ús d'aquestes dades. Els anomenats "word embeddings", o embeddings de paraules, són vectors de dimensionalitat baixa que s'obtenen mitjançant tècniques no supervisades aplicades a corpus textuals de grans volums. Com a resultat, cada paraula del diccionari es correspon amb un vector de nombres reals, el propòsit del qual és capturar propietats sintà ctiques i semà ntiques de la paraula corresponent. Moltes tasques de NLP involucren calcular la compatibilitat entre elements lèxics en l'à mbit d'una relació lingüÃstica. D'aquest tipus de relació en diem relació bilèxica. Aquesta tesi proposa models estadÃstics per a relacions bilèxiques que fan ús central d'embeddings de paraules, amb l'objectiu de millorar la generalització del model lingüÃstic a paraules no vistes durant l'entrenament. La tesi s'estructura en quatre parts. A la primera part presentem un model bilineal sobre embeddings de paraules que explota un conjunt petit de dades anotades sobre una relaxió bilèxica. L'algorisme d'aprenentatge treballa amb formes bilineals de poc rang, i indueix embeddings de poca dimensionalitat que estan especialitzats per la relació bilèxica per la qual s'han entrenat. Com a resultat, obtenim embeddings de paraules que corresponen a compressions d'embeddings per a una relació determinada. A la segona part de la tesi proposem una extensió del model bilineal a trilineal, i amb això proposem un nou model per a resoldre ambigüitats de sintagmes preposicionals que usa només embeddings de paraules. En una sèrie d'avaluacións, els nostres models funcionen de manera similar a l'estat de l'art. A més, el nostre mètode obté millores significatives en avaluacions en textos de dominis diferents al d'entrenament, simplement usant embeddings induïts amb textos dels dominis d'entrenament i d'avaluació. A la tercera part d'aquesta tesi proposem una altra extensió dels models bilineals per ampliar la cobertura lèxica en el context de models estadÃstics de traducció automà tica. El nostre model probabilÃstic obté, donada una paraula en la llengua d'origen, una llista de possibles traduccions en la llengua de destÃ. Fem això mitjançant una projecció d'embeddings pre-entrenats a un sub-espai comú, usant un model log-bilineal. EmpÃricament, observem una millora significativa en avaluacions en dominis diferents al d'entrenament. Finalment, a la quarta part de la tesi proposem un model no lineal que indueix una correspondència entre embeddings inicials i embeddings especialitzats, en el context de tasques d'anà lisi sintà ctica de dependències amb models neuronals. Mostrem que aquest mètode millora l'analisi de dependències, especialment en oracions amb paraules no vistes durant l'entrenament. També mostrem millores en un tasca d'anà lisi de sentiment
Compositional Fusion of Signals in Data Embedding
Embeddings in AI convert symbolic structures into fixed-dimensional vectors,
effectively fusing multiple signals. However, the nature of this fusion in
real-world data is often unclear. To address this, we introduce two methods:
(1) Correlation-based Fusion Detection, measuring correlation between known
attributes and embeddings, and (2) Additive Fusion Detection, viewing
embeddings as sums of individual vectors representing attributes.
Applying these methods, word embeddings were found to combine semantic and
morphological signals. BERT sentence embeddings were decomposed into individual
word vectors of subject, verb and object. In the knowledge graph-based
recommender system, user embeddings, even without training on demographic data,
exhibited signals of demographics like age and gender.
This study highlights that embeddings are fusions of multiple signals, from
Word2Vec components to demographic hints in graph embeddings
Compositional Fusion of Signals in Data Embedding
Embeddings in AI convert symbolic structures into fixed-dimensional vectors, effectively fusing multiple signals. However, the nature of this fusion in real-world data is often unclear. To address this, we introduce two methods: (1) Correlation-based Fusion Detection, measuring correlation between known attributes and embeddings, and (2) Additive Fusion Detection, viewing embeddings as sums of individual vectors representing attributes. Applying these methods, word embeddings were found to combine semantic and morphological signals. BERT sentence embeddings were decomposed into individual word vectors of subject, verb and object. In the knowledge graph-based recommender system, user embeddings, even without training on demographic data, exhibited signals of demographics like age and gender. This study highlights that embeddings are fusions of multiple signals, from Word2Vec components to demographic hints in graph embeddings
Modeling Language Variation and Universals: A Survey on Typological Linguistics for Natural Language Processing
Linguistic typology aims to capture structural and semantic variation across
the world's languages. A large-scale typology could provide excellent guidance
for multilingual Natural Language Processing (NLP), particularly for languages
that suffer from the lack of human labeled resources. We present an extensive
literature survey on the use of typological information in the development of
NLP techniques. Our survey demonstrates that to date, the use of information in
existing typological databases has resulted in consistent but modest
improvements in system performance. We show that this is due to both intrinsic
limitations of databases (in terms of coverage and feature granularity) and
under-employment of the typological features included in them. We advocate for
a new approach that adapts the broad and discrete nature of typological
categories to the contextual and continuous nature of machine learning
algorithms used in contemporary NLP. In particular, we suggest that such
approach could be facilitated by recent developments in data-driven induction
of typological knowledge
A Defense of Pure Connectionism
Connectionism is an approach to neural-networks-based cognitive modeling that encompasses the recent deep learning movement in artificial intelligence. It came of age in the 1980s, with its roots in cybernetics and earlier attempts to model the brain as a system of simple parallel processors. Connectionist models center on statistical inference within neural networks with empirically learnable parameters, which can be represented as graphical models. More recent approaches focus on learning and inference within hierarchical generative models. Contra influential and ongoing critiques, I argue in this dissertation that the connectionist approach to cognitive science possesses in principle (and, as is becoming increasingly clear, in practice) the resources to model even the most rich and distinctly human cognitive capacities, such as abstract, conceptual thought and natural language comprehension and production.
Consonant with much previous philosophical work on connectionism, I argue that a core principle—that proximal representations in a vector space have similar semantic values—is the key to a successful connectionist account of the systematicity and productivity of thought, language, and other core cognitive phenomena. My work here differs from preceding work in philosophy in several respects: (1) I compare a wide variety of connectionist responses to the systematicity challenge and isolate two main strands that are both historically important and reflected in ongoing work today: (a) vector symbolic architectures and (b) (compositional) vector space semantic models; (2) I consider very recent applications of these approaches, including their deployment on large-scale machine learning tasks such as machine translation; (3) I argue, again on the basis mostly of recent developments, for a continuity in representation and processing across natural language, image processing and other domains; (4) I explicitly link broad, abstract features of connectionist representation to recent proposals in cognitive science similar in spirit, such as hierarchical Bayesian and free energy minimization approaches, and offer a single rebuttal of criticisms of these related paradigms; (5) I critique recent alternative proposals that argue for a hybrid Classical (i.e. serial symbolic)/statistical model of mind; (6) I argue that defending the most plausible form of a connectionist cognitive architecture requires rethinking certain distinctions that have figured prominently in the history of the philosophy of mind and language, such as that between word- and phrase-level semantic content, and between inference and association
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