A Mention-Ranking Model for Abstract Anaphora Resolution

Resolving abstract anaphora is an important, but difficult task for text understanding. Yet, with recent advances in representation learning this task becomes a more tangible aim. A central property of abstract anaphora is that it establishes a relation between the anaphor embedded in the anaphoric sentence and its (typically non-nominal) antecedent. We propose a mention-ranking model that learns how abstract anaphors relate to their antecedents with an LSTM-Siamese Net. We overcome the lack of training data by generating artificial anaphoric sentence--antecedent pairs. Our model outperforms state-of-the-art results on shell noun resolution. We also report first benchmark results on an abstract anaphora subset of the ARRAU corpus. This corpus presents a greater challenge due to a mixture of nominal and pronominal anaphors and a greater range of confounders. We found model variants that outperform the baselines for nominal anaphors, without training on individual anaphor data, but still lag behind for pronominal anaphors. Our model selects syntactically plausible candidates and -- if disregarding syntax -- discriminates candidates using deeper features.Comment: In Proceedings of the 2017 Conference on Empirical Methods in Natural Language Processing (EMNLP). Copenhagen, Denmar

Shell nouns in English ? a personal roundup

Els encapsuladors en anglès ? una síntesi personal Aquest treball ofereix una retrospectiva personal sobre la noció i el fenomen discursiu de shell noun (o encapsulador, literalment nom closca). Després d?una breu introducció, discutirem alguns aspectes terminològics i metodològics i efectuarem algunes remarques sobre la classificació dels usos dels encapsuladors. Finalment, aportarem una revisió d?investigacions recents sobre l?origen i el desenvolupament diacrònic dels encapsuladors i de les construccions encapsuladores, i discutirem una sèrie de noves aportacions en l?estudi de l?encapsulació des de la introducció del concepte en els anys 90 del segle passat

Deep Learning With Sentiment Inference For Discourse-Oriented Opinion Analysis

Opinions are omnipresent in written and spoken text ranging from editorials, reviews, blogs, guides, and informal conversations to written and broadcast news. However, past research in NLP has mainly addressed explicit opinion expressions, ignoring implicit opinions. As a result, research in opinion analysis has plateaued at a somewhat superficial level, providing methods that only recognize what is explicitly said and do not understand what is implied. In this dissertation, we develop machine learning models for two tasks that presumably support propagation of sentiment in discourse, beyond one sentence. The first task we address is opinion role labeling, i.e.\ the task of detecting who expressed a given attitude toward what or who. The second task is abstract anaphora resolution, i.e.\ the task of finding a (typically) non-nominal antecedent of pronouns and noun phrases that refer to abstract objects like facts, events, actions, or situations in the preceding discourse. We propose a neural model for labeling of opinion holders and targets and circumvent the problems that arise from the limited labeled data. In particular, we extend the baseline model with different multi-task learning frameworks. We obtain clear performance improvements using semantic role labeling as the auxiliary task. We conduct a thorough analysis to demonstrate how multi-task learning helps, what has been solved for the task, and what is next. We show that future developments should improve the ability of the models to capture long-range dependencies and consider other auxiliary tasks such as dependency parsing or recognizing textual entailment. We emphasize that future improvements can be measured more reliably if opinion expressions with missing roles are curated and if the evaluation considers all mentions in opinion role coreference chains as well as discontinuous roles. To the best of our knowledge, we propose the first abstract anaphora resolution model that handles the unrestricted phenomenon in a realistic setting. We cast abstract anaphora resolution as the task of learning attributes of the relation that holds between the sentence with the abstract anaphor and its antecedent. We propose a Mention-Ranking siamese-LSTM model (MR-LSTM) for learning what characterizes the mentioned relation in a data-driven fashion. The current resources for abstract anaphora resolution are quite limited. However, we can train our models without conventional data for abstract anaphora resolution. In particular, we can train our models on many instances of antecedent-anaphoric sentence pairs. Such pairs can be automatically extracted from parsed corpora by searching for a common construction which consists of a verb with an embedded sentence (complement or adverbial), applying a simple transformation that replaces the embedded sentence with an abstract anaphor, and using the cut-off embedded sentence as the antecedent. We refer to the extracted data as silver data. We evaluate our MR-LSTM models in a realistic task setup in which models need to rank embedded sentences and verb phrases from the sentence with the anaphor as well as a few preceding sentences. We report the first benchmark results on an abstract anaphora subset of the ARRAU corpus \citep{uryupina_et_al_2016} which presents a greater challenge due to a mixture of nominal and pronominal anaphors as well as a greater range of confounders. We also use two additional evaluation datasets: a subset of the CoNLL-12 shared task dataset \citep{pradhan_et_al_2012} and a subset of the ASN corpus \citep{kolhatkar_et_al_2013_crowdsourcing}. We show that our MR-LSTM models outperform the baselines in all evaluation datasets, except for events in the CoNLL-12 dataset. We conclude that training on the small-scale gold data works well if we encounter the same type of anaphors at the evaluation time. However, the gold training data contains only six shell nouns and events and thus resolution of anaphors in the ARRAU corpus that covers a variety of anaphor types benefits from the silver data. Our MR-LSTM models for resolution of abstract anaphors outperform the prior work for shell noun resolution \citep{kolhatkar_et_al_2013} in their restricted task setup. Finally, we try to get the best out of the gold and silver training data by mixing them. Moreover, we speculate that we could improve the training on a mixture if we: (i) handle artifacts in the silver data with adversarial training and (ii) use multi-task learning to enable our models to make ranking decisions dependent on the type of anaphor. These proposals give us mixed results and hence a robust mixed training strategy remains a challenge

Shell nouns : in a systemic functional linguistics perspective

Tese de doutoramento, Linguística (Análise do Discurso), Universidade de Lisboa, Faculdade de Letras, 2015Shell nouns in a Systemic Functional Linguistics perspective. The aim of this thesis is to develop an account of shell nouns (Schmid, 2000) in a Systemic Functional Linguistics (SFL) perspective. Using a parallel corpus comprising five article submissions by Portuguese academics in the field of economics and five published articles on comparable topics, the ideational, interpersonal and textual functions of shell nouns are tagged at the strata of the lexicogrammar and discourse semantics using Corpus Tool version 2.7.4 (O’Donnell, 2008). The systems networks used to tag the corpus are grounded in SFL theory. The analysis shows that shell nouns constitute an important systemic resource for the writers of research articles, who need to build an argument, positioning themselves and their study to convince the discourse community that their paper makes a contribution to knowledge in their disciplinary field. They enable a text to unfold by compacting information realised as a clause or more elsewhere in the text. Thus they can help scaffold a text through hyper-Themes, hyper-News and internal conjunction. At the stratum of the lexicogrammar, anaphorically referring nominal groups with a shell noun as Head often compose Theme, where they constitute a shared point of departure for the clause. In a decoding relational clause whose Process is realised by a verb such as reveal, confirm, or suggest, an anaphorically referring shell noun that construes Token helps to explicitly build the writer’s argument. Shell nouns that construe the field of research, such as results and findings are common in this function. Mental, linguistic and factual shell nouns contribute to construing dialogic position, and coupling between interpersonal systems and textual systems enables the writer to align the reader with certain positions and disalign with others. Although most shell nouns are not field specific, because they can project a figure that instantiates an entity, they contribute to construing field, for example instantiating entities as the object of study of the empirical research. The capacity of shell nouns to function as described above derives from their status as semiotic abstractions, which can refer to text as fact or report and are grammatical metaphors. They can be seen as lying at the intersection of modality and the logico-semantic relations of projection and expansion, brought into being by the semogenic process of nominalisation. The writers of the published articles and article submissions are found to use shell nouns in all of the functions above, but there are differences in the relative shares of the functions, which may affect reader reactions to the text

Funkční a překladová korespondence ukazovacích zájmen v determinační funkci v překladu z angličtiny

Cílem bakalářské práce je popsat překladové protějšky anglických demonstrativ v determinační funkci v překladu z angličtiny do češtiny a zmapovat míru korespondence užívání ukazovacích zájmen v obou jazycích. Teoretická kapitola se nejdříve zaměřuje na anglická demonstrativa a definuje je coby determinátory z hlediska morfologického a syntaktického. Ukazovací zájmena slouží jako prostředky situační nebo textové reference, kterou lze rozdělit do tří podkategorií: anafora, katafora a tzv. neforická reference. Systém demonstrativ se dále dělí na formy odkazující na singulárové (this/that) nebo plurálové antecedenty (these/those). Na výběr demonstrativa má navíc vliv i vzdálenost mluvčího a referenta příslušného demonstrativa, přičemž percepce vzdálenosti se netýká pouze vztahu fyzické vzdálenosti či blízkosti. Teoretická část také postihuje relativně řídké případy, kdy se demonstrativum objevuje ve spojení s vlastním jménem (Vantage Theory) nebo funguje jako prostředek textové roviny (Gradient focus theory). Druhá část teoretického úvodu je zaměřena na morfo-syntaktický popis českých demonstrativ. Důležitým aspektem je neexistence kategorie určenosti v češtině a celkový flektivní charakter češtiny, což má za následek různou realizaci určitých gramatických struktur. Kvantitativně několikanásobně větší...The aim of this thesis is to analyse Czech translation counterparts of English demonstrative determiners and determine the degree of correspondence in the use of demonstratives in both languages. The first half of the theoretical chapter defines the English demonstrative determiners on the morpho-syntactic level. Demonstrative determiners in English carry either situational or textual reference, which can be further divided into anaphora, cataphora and the non-phoric reference. Demonstratives also distinguish between singular forms (this/that) and plural forms (these/those), as well as between proximal (this/these) and distal forms (that/those). The choice of either a proximal or a distal form is not always influenced by solely spatial relationships. Less frequent instances of a co- occurrence of a demonstrative and a proper name (Vantage Theory), and of demonstratives with prominent cohesive features (Gradient focus theory), are also discussed. The second half of the theoretical introduction is focused on a morpho-syntactic classification of Czech demonstratives. The inflectional character of Czech, together with the absence of the category of definiteness results in different realisations of certain grammatical structures. The quantitatively larger set of Czech demonstratives is classified...Department of the English Language and ELT MethodologyÚstav anglického jazyka a didaktikyFaculty of ArtsFilozofická fakult

How cultural identities are constructed in China's national holiday blockbuster : a perspective from political discourse analysis

The recent Chinese national blockbuster My People, My Country (MPMC), a movie consisting of 7 stories recounting 7 memorial moments and events since the founding of the People’s Republic of China, has evoked strong emotions among domestic Chinese citizens as well as Chinese diasporas overseas (Hou, 2019). Based on data by Maoyan’s website (2019), MPMC is ranked in the top ten of highest-grossing films in mainland China. As a propaganda film, the huge success of MPMC encourages us to wonder: why is it so successful and why did it receive such strong emotional responses? This question merits investigation as the answer will shed light on how cultural production is to create a shared national identity and further to serve political purpose in uniting populace in today’s new era (Gramsci, 1985; O’shannassy, 2008). Echoing the claim that MPMC was “aiming to awaken the shared memories of Chinese people around the world” (“China Focus”, 2019), I will take the approach of political discourse analysis (PDA) to probe into two specific questions: what strategies are used in constructing cultural identities? And how is MPMC different from past propaganda films, which, according to Teo (2019) and Veg (2012), directly extoll the virtues of the State and belong to high culture? In order to assess the effectiveness of the strategies employed in the movie in constructing national identities, I conducted a small-scale (25 samples) questionnaire survey among Chinese diasporas overseas to understand their feelings towards and comments on the movie (Hall, 2014). The questionnaire consists of 5 open questions investigating the participants’ feelings of this movie as well as which stories they liked/disliked the most. It was administered among 25 Chinese students studying at Ghent University. Feedback suggests that the audience is particularly impressed by elements they share affinity and familiarity with. For instance, the national anthem and theme song of the film (also entitled My People My Country) represent a shared memory: most, if not all, Chinese people, especially those born in 1980s and 1990s, were taught this song repeatedly in their school and university years. Interestingly, apart from these two general shared memories, smaller-scale but more targeted cultural content is employed too, such as the different dialects spoken by different characters throughout the narratives in the movie. These dialects represent the most spoken dialects in China. By employing cultural elements that are familiar to audience, MPMC manages to create proximity and further evoke a highly affective reaction with the participants. Moving to the second research question, I will particularly focus on examining the topics and structures of the 7 seemingly independent stories in the movie, both of which are considered important in PDA (Dunmire, 2012; van Dijk, 1997). The topics featuring the 7 stories vary but share several commonalities—all related to political events and ideologies, and are unfolded in a highly similar structure: all 7 stories end with success and happiness, at the expense of personal sacrifice. Based on such findings, I will further compare MPMC with previous nationalist films, such as Wolf Warrior 2 and Operation Red Sea, both of which are among top ten highest-grossing films and typical patriotic styles, as well as The Founding of a Republic, a tribute to the 60th national anniversary of People’s Republic of China. The comparison suggests an apparent shift from a focus on high-level or remote figures, such as soldiers from a special force or navy, to an emphasis on the popular culture in fostering patriotism. For example, inviting popular celebrities to act and seeing historical events from citizens’ perspectives are among the used strategies. The findings will enable us to better understand how cultural contents are used as tools for political purposes, such as creating unified national identity and maintain cultural hegemony (Gramsci, 1985)

Lexical vagueness in student writing

This study addresses the issue of underspecificity in undergraduate writing. Two corpora of South African undergraduate essays (writing in first and second language English) are compared to a corpus of academic papers (PW). The comparison is in terms of corpus-analytic methods and a discourse analytic approach to using definite expressions. So-called "abstract" nouns like problem, purpose, fact, example, and idea, identified as "carrier/shell" nouns, are often claimed to cause 'vagueness' in student writing, so students are advised not to use them. Yet corpus analysis (e.g. Biber et a!, 1999) shows they are a core feature of English academic vocabulary. Distinguishing between sense and reference clarifies a crucial difference between nouns with vague denotation, and noun phrases (NPs) with vague reference. A quantitative analysis of the corpora reveals that the students and PWs use both "shell" nouns, and the syntactic patterns in which they frequently occur, with similarly high frequency. However, the PW sub-corpus contains significantly more nouns than the student corpora and exhibits significantly more variety in the nouns used. Using a discourse-based approach, a second analysis focuses more closely on the discoursal structure of the texts, concentrating on definite referring expressions. A specially developed method of coding is used to categorise the way writers specify and constrain the referents of NPs containing 'abstract' nouns. Student writers in this study tend to use "shell" nouns not only as NP heads but, repetitively, within specifying phrases whose function should be to constrain reference. Hawkins' (1991) approach to definiteness is used to show that this embedding of 'vague' nouns in referring NPs, together with other discoursal features, stems from student writers inappropriately assuming shared knowledge. This in turn strengthens the argument that if student writers are to be viewed as apprentice PWs, learning to write for a 'general readership' must be seen as a crucial part of their training