125 research outputs found

    Advancing Multi-Modal Deep Learning: Towards Language-Grounded Visual Understanding

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    Using deep learning, computer vision now rivals people at object recognition and detection, opening doors to tackle new challenges in image understanding. Among these challenges, understanding and reasoning about language grounded visual content is of fundamental importance to advancing artificial intelligence. Recently, multiple datasets and algorithms have been created as proxy tasks towards this goal, with visual question answering (VQA) being the most widely studied. In VQA, an algorithm needs to produce an answer to a natural language question about an image. However, our survey of datasets and algorithms for VQA uncovered several sources of dataset bias and sub-optimal evaluation metrics that allowed algorithms to perform well by merely exploiting superficial statistical patterns. In this dissertation, we describe new algorithms and datasets that address these issues. We developed two new datasets and evaluation metrics that enable a more accurate measurement of abilities of a VQA model, and also expand VQA to include new abilities, such as reading text, handling out-of-vocabulary words, and understanding data-visualization. We also created new algorithms for VQA that have helped advance the state-of-the-art for VQA, including an algorithm that surpasses humans on two different chart question answering datasets about bar-charts, line-graphs and pie charts. Finally, we provide a holistic overview of several yet-unsolved challenges in not only VQA but vision and language research at large. Despite enormous progress, we find that a robust understanding and integration of vision and language is still an elusive goal, and much of the progress may be misleading due to dataset bias, superficial correlations and flaws in standard evaluation metrics. We carefully study and categorize these issues for several vision and language tasks and outline several possible paths towards development of safe, robust and trustworthy AI for language-grounded visual understanding

    Proceedings of the COLING 2004 Post Conference Workshop on Multilingual Linguistic Ressources MLR2004

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    International audienceIn an ever expanding information society, most information systems are now facing the "multilingual challenge". Multilingual language resources play an essential role in modern information systems. Such resources need to provide information on many languages in a common framework and should be (re)usable in many applications (for automatic or human use). Many centres have been involved in national and international projects dedicated to building har- monised language resources and creating expertise in the maintenance and further development of standardised linguistic data. These resources include dictionaries, lexicons, thesauri, word-nets, and annotated corpora developed along the lines of best practices and recommendations. However, since the late 90's, most efforts in scaling up these resources remain the responsibility of the local authorities, usually, with very low funding (if any) and few opportunities for academic recognition of this work. Hence, it is not surprising that many of the resource holders and developers have become reluctant to give free access to the latest versions of their resources, and their actual status is therefore currently rather unclear. The goal of this workshop is to study problems involved in the development, management and reuse of lexical resources in a multilingual context. Moreover, this workshop provides a forum for reviewing the present state of language resources. The workshop is meant to bring to the international community qualitative and quantitative information about the most recent developments in the area of linguistic resources and their use in applications. The impressive number of submissions (38) to this workshop and in other workshops and conferences dedicated to similar topics proves that dealing with multilingual linguistic ressources has become a very hot problem in the Natural Language Processing community. To cope with the number of submissions, the workshop organising committee decided to accept 16 papers from 10 countries based on the reviewers' recommendations. Six of these papers will be presented in a poster session. The papers constitute a representative selection of current trends in research on Multilingual Language Resources, such as multilingual aligned corpora, bilingual and multilingual lexicons, and multilingual speech resources. The papers also represent a characteristic set of approaches to the development of multilingual language resources, such as automatic extraction of information from corpora, combination and re-use of existing resources, online collaborative development of multilingual lexicons, and use of the Web as a multilingual language resource. The development and management of multilingual language resources is a long-term activity in which collaboration among researchers is essential. We hope that this workshop will gather many researchers involved in such developments and will give them the opportunity to discuss, exchange, compare their approaches and strengthen their collaborations in the field. The organisation of this workshop would have been impossible without the hard work of the program committee who managed to provide accurate reviews on time, on a rather tight schedule. We would also like to thank the Coling 2004 organising committee that made this workshop possible. Finally, we hope that this workshop will yield fruitful results for all participants

    Recognising Complex Mental States from Naturalistic Human-Computer Interactions

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    New advances in computer vision techniques will revolutionize the way we interact with computers, as they, together with other improvements, will help us build machines that understand us better. The face is the main non-verbal channel for human-human communication and contains valuable information about emotion, mood, and mental state. Affective computing researchers have investigated widely how facial expressions can be used for automatically recognizing affect and mental states. Nowadays, physiological signals can be measured by video-based techniques, which can also be utilised for emotion detection. Physiological signals, are an important indicator of internal feelings, and are more robust against social masking. This thesis focuses on computer vision techniques to detect facial expression and physiological changes for recognizing non-basic and natural emotions during human-computer interaction. It covers all stages of the research process from data acquisition, integration and application. Most previous studies focused on acquiring data from prototypic basic emotions acted out under laboratory conditions. To evaluate the proposed method under more practical conditions, two different scenarios were used for data collection. In the first scenario, a set of controlled stimulus was used to trigger the user’s emotion. The second scenario aimed at capturing more naturalistic emotions that might occur during a writing activity. In the second scenario, the engagement level of the participants with other affective states was the target of the system. For the first time this thesis explores how video-based physiological measures can be used in affect detection. Video-based measuring of physiological signals is a new technique that needs more improvement to be used in practical applications. A machine learning approach is proposed and evaluated to improve the accuracy of heart rate (HR) measurement using an ordinary camera during a naturalistic interaction with computer

    Recognising Complex Mental States from Naturalistic Human-Computer Interactions

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    New advances in computer vision techniques will revolutionize the way we interact with computers, as they, together with other improvements, will help us build machines that understand us better. The face is the main non-verbal channel for human-human communication and contains valuable information about emotion, mood, and mental state. Affective computing researchers have investigated widely how facial expressions can be used for automatically recognizing affect and mental states. Nowadays, physiological signals can be measured by video-based techniques, which can also be utilised for emotion detection. Physiological signals, are an important indicator of internal feelings, and are more robust against social masking. This thesis focuses on computer vision techniques to detect facial expression and physiological changes for recognizing non-basic and natural emotions during human-computer interaction. It covers all stages of the research process from data acquisition, integration and application. Most previous studies focused on acquiring data from prototypic basic emotions acted out under laboratory conditions. To evaluate the proposed method under more practical conditions, two different scenarios were used for data collection. In the first scenario, a set of controlled stimulus was used to trigger the user’s emotion. The second scenario aimed at capturing more naturalistic emotions that might occur during a writing activity. In the second scenario, the engagement level of the participants with other affective states was the target of the system. For the first time this thesis explores how video-based physiological measures can be used in affect detection. Video-based measuring of physiological signals is a new technique that needs more improvement to be used in practical applications. A machine learning approach is proposed and evaluated to improve the accuracy of heart rate (HR) measurement using an ordinary camera during a naturalistic interaction with computer

    Proceedings of the Seventh Italian Conference on Computational Linguistics CLiC-it 2020

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    On behalf of the Program Committee, a very warm welcome to the Seventh Italian Conference on Computational Linguistics (CLiC-it 2020). This edition of the conference is held in Bologna and organised by the University of Bologna. The CLiC-it conference series is an initiative of the Italian Association for Computational Linguistics (AILC) which, after six years of activity, has clearly established itself as the premier national forum for research and development in the fields of Computational Linguistics and Natural Language Processing, where leading researchers and practitioners from academia and industry meet to share their research results, experiences, and challenges

    Does the way museum staff define inspiration help them work with information from visitors' Social Media?

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    Since the early 2000s, Social Media has become part of the everyday activity of billions of people. Museums and galleries are part of this major cultural change - the largest museums attract millions of Social Media 'friends' and 'followers', and museums now use Social Media channels for marketing and audience engagement activities. Social Media has also become a more heavily-used source of data with which to investigate human behaviour. Therefore, this research investigated the potential uses of Social Media information to aid activities such as exhibition planning and development, or fundraising, in museums. Potential opportunities provided by the new Social Media platforms include the ability to capture data at high volume and then analyse them computationally. For instance, the links between entities on a Social Media platform can be analysed. Who follows who? Who created the content related to a specific event, and when? How did communication flow between people and organisations? The computerised analysis techniques used to answer such questions can generate statistics for measuring concepts such as the 'reach' of a message across a network (often equated simply with the potential size of the a message's audience) or the degree of 'engagement' with content (often a simple count of the number of responses, or the number of instances of communication between correspondents). Other computational analysis opportunities related to Social Media rely upon various Natural Language Processing (NLP) techniques; for example indexing content and counting term frequency, or using lexicons or online knowledge bases to relate content to concepts. Museums, galleries and other cultural organisations have known for some time, however, that simple quantifications of their audiences (the number of tickets sold for an exhibition, for example), while certainly providing indications of an event's success, do not tell the whole story. While it is important to know that thousands of people have visited an exhibition, it is also part of a museum's remit to inspire the audience, too. A budding world-class artist or ground-breaking engineer could have been one of the thousands in attendance, and the exhibition in question could have been key to the development of their artistic or technical ideas. It is potentially helpful to museums and galleries to know when they have inspired members of their audience, and to be able to tell convincing stories about instances of inspiration, if their full value to society is to be judged. This research, undertaken in participation with two museums, investigated the feasibility of using new data sources from Social Media to capture potential expressions of inspiration made by visitors. With a background in IT systems development, the researcher developed three prototype systems during three cycles of Action Research, and used them to collect and analyse data from the Twitter Social Media platform. This work had two outcomes: firstly, prototyping enabled investigation of the technical constraints of extracting data from a Social Media platform (Twitter), and the computing processes used to analyse that data. Secondly, and more importantly, the prototypes were used to assess potential changes to the work of museum staff information about events visited and experienced by visitors was synthesised, then investigated, discussed and evaluated with the collaborative partners, in order to assess the meaning and value of such information for them. Could the museums use the information in their event and exhibition planning? How might it fit in with event evaluation? Was it clear to the museum what the information meant? What were the risks of misinterpretation? The research made several contributions. Firstly, the research developed a definition of inspiration that resonated with museum staff. While this definition was similar to the definition of 'engagement' from the marketing literature, one difference was an emphasis upon creativity. The second set of contributions related to a deeper understanding of Social Media from museums' perspective, and included findings about how Social Media information could be used to segment current and potential audiences by 'special interest', and find potential expressions of creativity and innovation in the audience's responses to museum activities. These findings also considered some of the pitfalls of working with data from Social Media, in particular the tendency of museum staff to use the information to confirm positive biases, and the often hidden biases caused by the mediating effects of the platforms from which the data came. The final major contribution was a holistic analysis of the ways in which Social Media information could be integrated into the work of a museum, by helping to plan and evaluate audience development and engagement. This aspect of the research also highlighted some of the dangers of an over-dependency upon individual Social Media platforms which was previously absent from the museums literature

    An Urdu semantic tagger - lexicons, corpora, methods and tools

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    Extracting and analysing meaning-related information from natural language data has attracted the attention of researchers in various fields, such as Natural Language Processing (NLP), corpus linguistics, data sciences, etc. An important aspect of such automatic information extraction and analysis is the semantic annotation of language data using semantic annotation tool (a.k.a semantic tagger). Generally, different semantic annotation tools have been designed to carry out various levels of semantic annotations, for instance, sentiment analysis, word sense disambiguation, content analysis, semantic role labelling, etc. These semantic annotation tools identify or tag partial core semantic information of language data, moreover, they tend to be applicable only for English and other European languages. A semantic annotation tool that can annotate semantic senses of all lexical units (words) is still desirable for the Urdu language based on USAS (the UCREL Semantic Analysis System) semantic taxonomy, in order to provide comprehensive semantic analysis of Urdu language text. This research work report on the development of an Urdu semantic tagging tool and discuss challenging issues which have been faced in this Ph.D. research work. Since standard NLP pipeline tools are not widely available for Urdu, alongside the Urdu semantic tagger a suite of newly developed tools have been created: sentence tokenizer, word tokenizer and part-of-speech tagger. Results for these proposed tools are as follows: word tokenizer reports F1F_1 of 94.01\%, and accuracy of 97.21\%, sentence tokenizer shows F1_1 of 92.59\%, and accuracy of 93.15\%, whereas, POS tagger shows an accuracy of 95.14\%. The Urdu semantic tagger incorporates semantic resources (lexicon and corpora) as well as semantic field disambiguation methods. In terms of novelty, the NLP pre-processing tools are developed either using rule-based, statistical, or hybrid techniques. Furthermore, all semantic lexicons have been developed using a novel combination of automatic or semi-automatic approaches: mapping, crowdsourcing, statistical machine translation, GIZA++, word embeddings, and named entity. A large multi-target annotated corpus is also constructed using a semi-automatic approach to test accuracy of the Urdu semantic tagger, proposed corpus is also used to train and test supervised multi-target Machine Learning classifiers. The results show that Random k-labEL Disjoint Pruned Sets and Classifier Chain multi-target classifiers outperform all other classifiers on the proposed corpus with a Hamming Loss of 0.06\% and Accuracy of 0.94\%. The best lexical coverage of 88.59\%, 99.63\%, 96.71\% and 89.63\% are obtained on several test corpora. The developed Urdu semantic tagger shows encouraging precision on the proposed test corpus of 79.47\%

    Addressing the data bottleneck in implicit discourse relation classification

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    When humans comprehend language, their interpretation consists of more than just the sum of the content of the sentences. Additional logic and semantic links (known as coherence relations or discourse relations) are inferred between sentences/clauses in the text. The identification of discourse relations is beneficial for various NLP applications such as question-answering, summarization, machine translation, information extraction, etc. Discourse relations are categorized into implicit and explicit discourse relations depending on whether there is an explicit discourse marker between the arguments. In this thesis, we mainly focus on the implicit discourse relation classification, given that with the explicit markers acting as informative cues, the explicit relations are relatively easier to identify for machines. The recent neural network-based approaches in particular suffer from insufficient training (and test) data. As shown in Chapter 3 of this thesis, we start out by showing to what extent the limited data size is a problem in implicit discourse relation classification and propose data augmentation methods with the help of cross-lingual data. And then we propose several approaches for better exploiting and encoding various types of existing data in the discourse relation classification task. Most of the existing machine learning methods train on sections 2-21 of the PDTB and test on section 23, which only includes a total of less than 800 implicit discourse relation instances. With the help of cross validation, we argue that the standard test section of the PDTB is too small to draw conclusions upon. With more test samples in the cross validation, we would come to very different conclusions about whether a feature is generally useful. Second, we propose a simple approach to automatically extract samples of implicit discourse relations from multilingual parallel corpus via back-translation. After back-translating from target languages, it is easy for the discourse parser to identify those examples that are originally implicit but explicit in the back-translations. Having those additional data in the training set, the experiments show significant improvements on different settings. Finally, having better encoding ability is also of crucial importance in terms of improving classification performance. We propose different methods including a sequence-to-sequence neural network and a memory component to help have a better representation of the arguments. We also show that having the correct next sentence is beneficial for the task within and across domains, with the help of the BERT (Devlin et al., 2019) model. When it comes to a new domain, it is beneficial to integrate external domain-specific knowledge. In Chapter 8, we show that with the entity-enhancement, the performance on BioDRB is improved significantly, comparing with other BERT-based methods. In sum, the studies reported in this dissertation contribute to addressing the data bottleneck problem in implicit discourse relation classification and propose corresponding approaches that achieve 54.82% and 69.57% on PDTB and BioDRB respectively.Wenn Menschen Sprache verstehen, besteht ihre Interpretation aus mehr als nur der Summe des Inhalts der Sätze. Zwischen Sätzen im Text werden zusätzliche logische und semantische Verknüpfungen (sogenannte Kohärenzrelationen oder Diskursrelationen) hergeleitet. Die Identifizierung von Diskursrelationen ist für verschiedene NLP-Anwendungen wie Frage- Antwort, Zusammenfassung, maschinelle Übersetzung, Informationsextraktion usw. von Vorteil. Diskursrelationen werden in implizite und explizite Diskursrelationen unterteilt, je nachdem, ob es eine explizite Diskursrelationen zwischen den Argumenten gibt. In dieser Arbeit konzentrieren wir uns hauptsächlich auf die Klassifizierung der impliziten Diskursrelationen, da die expliziten Marker als hilfreiche Hinweise dienen und die expliziten Beziehungen für Maschinen relativ leicht zu identifizieren sind. Es wurden verschiedene Ansätze vorgeschlagen, die bei der impliziten Diskursrelationsklassifikation beeindruckende Ergebnisse erzielt haben. Die meisten von ihnen leiden jedoch darunter, dass die Daten für auf neuronalen Netzen basierende Methoden unzureichend sind. In dieser Arbeit gehen wir zunächst auf das Problem begrenzter Daten bei dieser Aufgabe ein und schlagen dann Methoden zur Datenanreicherung mit Hilfe von sprachübergreifenden Daten vor. Zuletzt schlagen wir mehrere Methoden vor, um die Argumente aus verschiedenen Aspekten besser kodieren zu können. Die meisten der existierenden Methoden des maschinellen Lernens werden auf den Abschnitten 2-21 der PDTB trainiert und auf dem Abschnitt 23 getestet, der insgesamt nur weniger als 800 implizite Diskursrelationsinstanzen enthält. Mit Hilfe der Kreuzvalidierung argumentieren wir, dass der Standardtestausschnitt der PDTB zu klein ist um daraus Schlussfolgerungen zu ziehen. Mit mehr Teststichproben in der Kreuzvalidierung würden wir zu anderen Schlussfolgerungen darüber kommen, ob ein Merkmal für diese Aufgabe generell vorteilhaft ist oder nicht, insbesondere wenn wir einen relativ großen Labelsatz verwenden. Wenn wir nur unseren kleinen Standardtestsatz herausstellen, laufen wir Gefahr, falsche Schlüsse darüber zu ziehen, welche Merkmale hilfreich sind. Zweitens schlagen wir einen einfachen Ansatz zur automatischen Extraktion von Samples impliziter Diskursrelationen aus mehrsprachigen Parallelkorpora durch Rückübersetzung vor. Er ist durch den Explikationsprozess motiviert, wenn Menschen einen Text übersetzen. Nach der Rückübersetzung aus den Zielsprachen ist es für den Diskursparser leicht, diejenigen Beispiele zu identifizieren, die ursprünglich implizit, in den Rückübersetzungen aber explizit enthalten sind. Da diese zusätzlichen Daten im Trainingsset enthalten sind, zeigen die Experimente signifikante Verbesserungen in verschiedenen Situationen. Wir verwenden zunächst nur französisch-englische Paare und haben keine Kontrolle über die Qualität und konzentrieren uns meist auf die satzinternen Relationen. Um diese Fragen in Angriff zu nehmen, erweitern wir die Idee später mit mehr Vorverarbeitungsschritten und mehr Sprachpaaren. Mit den Mehrheitsentscheidungen aus verschiedenen Sprachpaaren sind die gemappten impliziten Labels zuverlässiger. Schließlich ist auch eine bessere Kodierfähigkeit von entscheidender Bedeutung für die Verbesserung der Klassifizierungsleistung. Wir schlagen ein neues Modell vor, das aus einem Klassifikator und einem Sequenz-zu-Sequenz-Modell besteht. Neben der korrekten Vorhersage des Labels werden sie auch darauf trainiert, eine Repräsentation der Diskursrelationsargumente zu erzeugen, indem sie versuchen, die Argumente einschließlich eines geeigneten impliziten Konnektivs vorherzusagen. Die neuartige sekundäre Aufgabe zwingt die interne Repräsentation dazu, die Semantik der Relationsargumente vollständiger zu kodieren und eine feinkörnigere Klassifikation vorzunehmen. Um das allgemeine Wissen in Kontexten weiter zu erfassen, setzen wir auch ein Gedächtnisnetzwerk ein, um eine explizite Kontextrepräsentation von Trainingsbeispielen für Kontexte zu erhalten. Für jede Testinstanz erzeugen wir durch gewichtetes Lesen des Gedächtnisses einen Wissensvektor. Wir evaluieren das vorgeschlagene Modell unter verschiedenen Bedingungen und die Ergebnisse zeigen, dass das Modell mit dem Speichernetzwerk die Vorhersage von Diskursrelationen erleichtern kann, indem es Beispiele auswählt, die eine ähnliche semantische Repräsentation und Diskursrelationen aufweisen. Auch wenn ein besseres Verständnis, eine Kodierung und semantische Interpretation für die Aufgabe der impliziten Diskursrelationsklassifikation unerlässlich und nützlich sind, so leistet sie doch nur einen Teil der Arbeit. Ein guter impliziter Diskursrelationsklassifikator sollte sich auch der bevorstehenden Ereignisse, Ursachen, Folgen usw. bewusst sein, um die Diskurserwartung in die Satzdarstellungen zu kodieren. Mit Hilfe des kürzlich vorgeschlagenen BERT-Modells versuchen wir herauszufinden, ob es für die Aufgabe vorteilhaft ist, den richtigen nächsten Satz zu haben oder nicht. Die experimentellen Ergebnisse zeigen, dass das Entfernen der Aufgabe zur Vorhersage des nächsten Satzes die Leistung sowohl innerhalb der Domäne als auch domänenübergreifend stark beeinträchtigt. Die begrenzte Fähigkeit von BioBERT, domänenspezifisches Wissen, d.h. Entitätsinformationen, Entitätsbeziehungen etc. zu erlernen, motiviert uns, externes Wissen in die vortrainierten Sprachmodelle zu integrieren. Wir schlagen eine unüberwachte Methode vor, bei der Information-Retrieval-System und Wissensgraphen-Techniken verwendet werden, mit der Annahme, dass, wenn zwei Instanzen ähnliche Entitäten in beiden relationalen Argumenten teilen, die Wahrscheinlichkeit groß ist, dass sie die gleiche oder eine ähnliche Diskursrelation haben. Der Ansatz erzielt vergleichbare Ergebnisse auf BioDRB, verglichen mit Baselinemodellen. Anschließend verwenden wir die extrahierten relevanten Entitäten zur Verbesserung des vortrainierten Modells K-BERT, um die Bedeutung der Argumente besser zu kodieren und das ursprüngliche BERT und BioBERT mit einer Genauigkeit von 6,5% bzw. 2% zu übertreffen. Zusammenfassend trägt diese Dissertation dazu bei, das Problem des Datenengpasses bei der impliziten Diskursrelationsklassifikation anzugehen, und schlägt entsprechende Ansätze in verschiedenen Aspekten vor, u.a. die Darstellung des begrenzten Datenproblems und der Risiken bei der Schlussfolgerung daraus; die Erfassung automatisch annotierter Daten durch den Explikationsprozess während der manuellen Übersetzung zwischen Englisch und anderen Sprachen; eine bessere Repräsentation von Diskursrelationsargumenten; Entity-Enhancement mit einer unüberwachten Methode und einem vortrainierten Sprachmodell

    Gamifying Language Resource Acquisition

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    PhD ThesisNatural Language Processing, is an important collection of methods for processing the vast amounts of available natural language text we continually produce. These methods make use of supervised learning, an approach that learns from large amounts of annotated data. As humans, we’re able to provide information about text that such systems can learn from. Historically, this was carried out by small groups of experts. However, this did not scale. This led to various crowdsourcing approaches being taken that used large pools of non-experts. The traditional form of crowdsourcing was to pay users small amounts of money to complete tasks. As time progressed, gamification approaches such as GWAPs, showed various benefits over the micro-payment methods used before. These included a cost saving, worker training opportunities, increased worker engagement and potential to far exceed the scale of crowdsourcing. While these were successful in domains such as image labelling, they struggled in the domain of text annotation, which wasn’t such a natural fit. Despite many challenges, there were also clearly many opportunities and benefits to applying this approach to text annotation. Many of these are demonstrated by Phrase Detectives. Based on lessons learned from Phrase Detectives and investigations into other GWAPs, in this work, we attempt to create full GWAPs for NLP, extracting the benefits of the methodology. This includes training, high quality output from non-experts and a truly game-like GWAP design that players are happy to play voluntarily
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