50 resultados para Syntactic And Semantic Comprehension Tasks
em Aston University Research Archive
Resumo:
Spoken language comprehension is known to involve a large left-dominant network of fronto-temporal brain regions, but there is still little consensus about how the syntactic and semantic aspects of language are processed within this network. In an fMRI study, volunteers heard spoken sentences that contained either syntactic or semantic ambiguities as well as carefully matched low-ambiguity sentences. Results showed ambiguity-related responses in the posterior left inferior frontal gyrus (pLIFG) and posterior left middle temporal regions. The pLIFG activations were present for both syntactic and semantic ambiguities suggesting that this region is not specialised for processing either semantic or syntactic information, but instead performs cognitive operations that are required to resolve different types of ambiguity irrespective of their linguistic nature, for example by selecting between possible interpretations or reinterpreting misparsed sentences. Syntactic ambiguities also produced activation in the posterior middle temporal gyrus. These data confirm the functional relationship between these two brain regions and their importance in constructing grammatical representations of spoken language.
Resumo:
Early, lesion-based models of language processing suggested that semantic and phonological processes are associated with distinct temporal and parietal regions respectively, with frontal areas more indirectly involved. Contemporary spatial brain mapping techniques have not supported such clear-cut segregation, with strong evidence of activation in left temporal areas by both processes and disputed evidence of involvement of frontal areas in both processes. We suggest that combining spatial information with temporal and spectral data may allow a closer scrutiny of the differential involvement of closely overlapping cortical areas in language processing. Using beamforming techniques to analyze magnetoencephalography data, we localized the neuronal substrates underlying primed responses to nouns requiring either phonological or semantic processing, and examined the associated measures of time and frequency in those areas where activation was common to both tasks. Power changes in the beta (14-30 Hz) and gamma (30-50 Hz) frequency bandswere analyzed in pre-selected time windows of 350-550 and 500-700ms In left temporal regions, both tasks elicited power changes in the same time window (350-550 ms), but with different spectral characteristics, low beta (14-20 Hz) for the phonological task and high beta (20-30 Hz) for the semantic task. In frontal areas (BA10), both tasks elicited power changes in the gamma band (30-50 Hz), but in different time windows, 500-700ms for the phonological task and 350-550ms for the semantic task. In the left inferior parietal area (BA40), both tasks elicited changes in the 20-30 Hz beta frequency band but in different time windows, 350-550ms for the phonological task and 500-700ms for the semantic task. Our findings suggest that, where spatial measures may indicate overlapping areas of involvement, additional beamforming techniques can demonstrate differential activation in time and frequency domains. © 2012 McNab, Hillebrand, Swithenby and Rippon.
Resumo:
Verbal working memory and emotional self-regulation are impaired in Bipolar Disorder (BD). Our aim was to investigate the effect of Lamotrigine (LTG), which is effective in the clinical management of BD, on the neural circuits subserving working memory and emotional processing. Functional Magnetic Resonance Imaging data from 12 stable BD patients was used to detect LTG-induced changes as the differences in brain activity between drug-free and post-LTG monotherapy conditions during a verbal working memory (N-back sequential letter task) and an angry facial affect recognition task. For both tasks, LGT monotherapy compared to baseline was associated with increased activation mostly within the prefrontal cortex and cingulate gyrus, in regions normally engaged in verbal working memory and emotional processing. Therefore, LTG monotherapy in BD patients may enhance cortical function within neural circuits involved in memory and emotional self-regulation. © 2007 Elsevier B.V. and ECNP.
Resumo:
This work explores the relevance of semantic and linguistic description to translation, theory and practice. It is aimed towards a practical model of approach to texts to translate. As literary texts [poetry mainly] are the focus of attention, so are stylistic matters. Note, however, that 'style', and, to some extent, the conclusions of the work, are not limited to so-called literary texts. The study of semantic description reveals that most translation problems do not stem from the cognitive (langue-related), but rather from the contextual (parole-related) aspects of meaning. Thus, any linguistic model that fails to account for the latter is bound to fall short. T.G.G. does, whereas Systemics, concerned with both the 'Iangue' and 'parole' (stylistic and sociolinguistic mainly) aspects of meaning, provides a useful framework of approach to texts to translate. Two essential semantic principles for translation are: that meaning is the property of a language (Firth); and the 'relativity of meaning assignments' (Tymoczko). Both imply that meaning can only be assessed, correctly, in the relevant socio-cultural background. Translation is seen as a restricted creation, and the translator's encroach as a three-dimensional critical one. To encompass the most technical to the most literary text, and account for variations in emphasis in any text, translation theory must be based on typology of function Halliday's ideational, interpersonal and textual, or, Buhler's symbol, signal, symptom, Functions3. Function Coverall and specific] will dictate aims and method, and also provide the critic with criteria to assess translation Faithfulness. Translation can never be reduced to purely objective methods, however. Intuitive procedures intervene, in textual interpretation and analysis, in the choice of equivalents, and in the reception of a translation. Ultimately, translation, theory and practice, may perhaps constitute the touchstone as regards the validity of linguistic and semantic theories.
Resumo:
In a series of experiments, we tested category-specific activation in normal parti¬cipants using magnetoencephalography (MEG). Our experiments explored the temporal processing of objects, as MEG characterises neural activity on the order of milliseconds. Our experiments explored object-processing, including assessing the time-course of ob¬ject naming, early differences in processing living compared with nonliving objects and processing objects at the basic compared with the domain level, and late differences in processing living compared with nonliving objects and processing objects at the basic compared with the domain level. In addition to studies using normal participants, we also utilised MEG to explore category-specific processing in a patient with a deficit for living objects. Our findings support the cascade model of object naming (Humphreys et al., 1988). In addition, our findings using normal participants demonstrate early, category-specific perceptual differences. These findings are corroborated by our patient study. In our assessment of the time-course of category-specific effects as well as a separate analysis designed to measure semantic differences between living and nonliving objects, we found support for the sensory/motor model of object naming (Martin, 1998), in addition to support for the cascade model of object naming. Thus, object processing in normal participants appears to be served by a distributed network in the brain, and there are both perceptual and semantic differences between living and nonliving objects. A separate study assessing the influence of the level at which you are asked to identify an object on processing in the brain found evidence supporting the convergence zone hypothesis (Damasio, 1989). Taken together, these findings indicate the utility of MEG in exploring the time-course of object processing, isolating early perceptual and later semantic effects within the brain.
Resumo:
Motivation: In molecular biology, molecular events describe observable alterations of biomolecules, such as binding of proteins or RNA production. These events might be responsible for drug reactions or development of certain diseases. As such, biomedical event extraction, the process of automatically detecting description of molecular interactions in research articles, attracted substantial research interest recently. Event trigger identification, detecting the words describing the event types, is a crucial and prerequisite step in the pipeline process of biomedical event extraction. Taking the event types as classes, event trigger identification can be viewed as a classification task. For each word in a sentence, a trained classifier predicts whether the word corresponds to an event type and which event type based on the context features. Therefore, a well-designed feature set with a good level of discrimination and generalization is crucial for the performance of event trigger identification. Results: In this article, we propose a novel framework for event trigger identification. In particular, we learn biomedical domain knowledge from a large text corpus built from Medline and embed it into word features using neural language modeling. The embedded features are then combined with the syntactic and semantic context features using the multiple kernel learning method. The combined feature set is used for training the event trigger classifier. Experimental results on the golden standard corpus show that >2.5% improvement on F-score is achieved by the proposed framework when compared with the state-of-the-art approach, demonstrating the effectiveness of the proposed framework. © 2014 The Author 2014. The source code for the proposed framework is freely available and can be downloaded at http://cse.seu.edu.cn/people/zhoudeyu/ETI_Sourcecode.zip.
Resumo:
This thesis presents a new approach to designing large organizational databases. The approach emphasizes the need for a holistic approach to the design process. The development of the proposed approach was based on a comprehensive examination of the issues of relevance to the design and utilization of databases. Such issues include conceptual modelling, organization theory, and semantic theory. The conceptual modelling approach presented in this thesis is developed over three design stages, or model perspectives. In the semantic perspective, concept definitions were developed based on established semantic principles. Such definitions rely on meaning - provided by intension and extension - to determine intrinsic conceptual definitions. A tool, called meaning-based classification (MBC), is devised to classify concepts based on meaning. Concept classes are then integrated using concept definitions and a set of semantic relations which rely on concept content and form. In the application perspective, relationships are semantically defined according to the application environment. Relationship definitions include explicit relationship properties and constraints. The organization perspective introduces a new set of relations specifically developed to maintain conformity of conceptual abstractions with the nature of information abstractions implied by user requirements throughout the organization. Such relations are based on the stratification of work hierarchies, defined elsewhere in the thesis. Finally, an example of an application of the proposed approach is presented to illustrate the applicability and practicality of the modelling approach.
Resumo:
Time after time… and aspect and mood. Over the last twenty five years, the study of time, aspect and - to a lesser extent - mood acquisition has enjoyed increasing popularity and a constant widening of its scope. In such a teeming field, what can be the contribution of this book? We believe that it is unique in several respects. First, this volume encompasses studies from different theoretical frameworks: functionalism vs generativism or function-based vs form-based approaches. It also brings together various sub-fields (first and second language acquisition, child and adult acquisition, bilingualism) that tend to evolve in parallel rather than learn from each other. A further originality is that it focuses on a wide range of typologically different languages, and features less studied languages such as Korean and Bulgarian. Finally, the book gathers some well-established scholars, young researchers, and even research students, in a rich inter-generational exchange, that ensures the survival but also the renewal and the refreshment of the discipline. The book at a glance The first part of the volume is devoted to the study of child language acquisition in monolingual, impaired and bilingual acquisition, while the second part focuses on adult learners. In this section, we will provide an overview of each chapter. The first study by Aviya Hacohen explores the acquisition of compositional telicity in Hebrew L1. Her psycholinguistic approach contributes valuable data to refine theoretical accounts. Through an innovating methodology, she gathers information from adults and children on the influence of definiteness, number, and the mass vs countable distinction on the constitution of a telic interpretation of the verb phrase. She notices that the notion of definiteness is mastered by children as young as 10, while the mass/count distinction does not appear before 10;7. However, this does not entail an adult-like use of telicity. She therefore concludes that beyond definiteness and noun type, pragmatics may play an important role in the derivation of Hebrew compositional telicity. For the second chapter we move from a Semitic language to a Slavic one. Milena Kuehnast focuses on the acquisition of negative imperatives in Bulgarian, a form that presents the specificity of being grammatical only with the imperfective form of the verb. The study examines how 40 Bulgarian children distributed in two age-groups (15 between 2;11-3;11, and 25 between 4;00 and 5;00) develop with respect to the acquisition of imperfective viewpoints, and the use of imperfective morphology. It shows an evolution in the recourse to expression of force in the use of negative imperatives, as well as the influence of morphological complexity on the successful production of forms. With Yi-An Lin’s study, we concentrate both on another type of informant and of framework. Indeed, he studies the production of children suffering from Specific Language Impairment (SLI), a developmental language disorder the causes of which exclude cognitive impairment, psycho-emotional disturbance, and motor-articulatory disorders. Using the Leonard corpus in CLAN, Lin aims to test two competing accounts of SLI (the Agreement and Tense Omission Model [ATOM] and his own Phonetic Form Deficit Model [PFDM]) that conflicts on the role attributed to spellout in the impairment. Spellout is the point at which the Computational System for Human Language (CHL) passes over the most recently derived part of the derivation to the interface components, Phonetic Form (PF) and Logical Form (LF). ATOM claims that SLI sufferers have a deficit in their syntactic representation while PFDM suggests that the problem only occurs at the spellout level. After studying the corpus from the point of view of tense / agreement marking, case marking, argument-movement and auxiliary inversion, Lin finds further support for his model. Olga Gupol, Susan Rohstein and Sharon Armon-Lotem’s chapter offers a welcome bridge between child language acquisition and multilingualism. Their study explores the influence of intensive exposure to L2 Hebrew on the development of L1 Russian tense and aspect morphology through an elicited narrative. Their informants are 40 Russian-Hebrew sequential bilingual children distributed in two age groups 4;0 – 4;11 and 7;0 - 8;0. They come to the conclusion that bilingual children anchor their narratives in perfective like monolinguals. However, while aware of grammatical aspect, bilinguals lack the full form-function mapping and tend to overgeneralize the imperfective on the principles of simplicity (as imperfective are the least morphologically marked forms), universality (as it covers more functions) and interference. Rafael Salaberry opens the second section on foreign language learners. In his contribution, he reflects on the difficulty L2 learners of Spanish encounter when it comes to distinguishing between iterativity (conveyed with the use of the preterite) and habituality (expressed through the imperfect). He examines in turn the theoretical views that see, on the one hand, habituality as part of grammatical knowledge and iterativity as pragmatic knowledge, and on the other hand both habituality and iterativity as grammatical knowledge. He comes to the conclusion that the use of preterite as a default past tense marker may explain the impoverished system of aspectual distinctions, not only at beginners but also at advanced levels, which may indicate that the system is differentially represented among L1 and L2 speakers. Acquiring the vast array of functions conveyed by a form is therefore no mean feat, as confirmed by the next study. Based on the prototype theory, Kathleen Bardovi-Harlig’s chapter focuses on the development of the progressive in L2 English. It opens with an overview of the functions of the progressive in English. Then, a review of acquisition research on the progressive in English and other languages is provided. The bulk of the chapter reports on a longitudinal study of 16 learners of L2 English and shows how their use of the progressive expands from the prototypical uses of process and continuousness to the less prototypical uses of repetition and future. The study concludes that the progressive spreads in interlanguage in accordance with prototype accounts. However, it suggests additional stages, not predicted by the Aspect Hypothesis, in the development from activities and accomplishments at least for the meaning of repeatedness. A similar theoretical framework is adopted in the following chapter, but it deals with a lesser studied language. Hyun-Jin Kim revisits the claims of the Aspect Hypothesis in relation to the acquisition of L2 Korean by two L1 English learners. Inspired by studies on L2 Japanese, she focuses on the emergence and spread of the past / perfective marker ¬–ess- and the progressive – ko iss- in the interlanguage of her informants throughout their third and fourth semesters of study. The data collected through six sessions of conversational interviews and picture description tasks seem to support the Aspect Hypothesis. Indeed learners show a strong association between past tense and accomplishments / achievements at the start and a gradual extension to other types; a limited use of past / perfective marker with states and an affinity of progressive with activities / accomplishments and later achievements. In addition, - ko iss– moves from progressive to resultative in the specific category of Korean verbs meaning wear / carry. While the previous contributions focus on function, Evgeniya Sergeeva and Jean-Pierre Chevrot’s is interested in form. The authors explore the acquisition of verbal morphology in L2 French by 30 instructed native speakers of Russian distributed in a low and high levels. They use an elicitation task for verbs with different models of stem alternation and study how token frequency and base forms influence stem selection. The analysis shows that frequency affects correct production, especially among learners with high proficiency. As for substitution errors, it appears that forms with a simple structure are systematically more frequent than the target form they replace. When a complex form serves as a substitute, it is more frequent only when it is replacing another complex form. As regards the use of base forms, the 3rd person singular of the present – and to some extent the infinitive – play this role in the corpus. The authors therefore conclude that the processing of surface forms can be influenced positively or negatively by the frequency of the target forms and of other competing stems, and by the proximity of the target stem to a base form. Finally, Martin Howard’s contribution takes up the challenge of focusing on the poorer relation of the TAM system. On the basis of L2 French data obtained through sociolinguistic interviews, he studies the expression of futurity, conditional and subjunctive in three groups of university learners with classroom teaching only (two or three years of university teaching) or with a mixture of classroom teaching and naturalistic exposure (2 years at University + 1 year abroad). An analysis of relative frequencies leads him to suggest a continuum of use going from futurate present to conditional with past hypothetic conditional clauses in si, which needs to be confirmed by further studies. Acknowledgements The present volume was inspired by the conference Acquisition of Tense – Aspect – Mood in First and Second Language held on 9th and 10th February 2008 at Aston University (Birmingham, UK) where over 40 delegates from four continents and over a dozen countries met for lively and enjoyable discussions. This collection of papers was double peer-reviewed by an international scientific committee made of Kathleen Bardovi-Harlig (Indiana University), Christine Bozier (Lund Universitet), Alex Housen (Vrije Universiteit Brussel), Martin Howard (University College Cork), Florence Myles (Newcastle University), Urszula Paprocka (Catholic University of Lublin), †Clive Perdue (Université Paris 8), Michel Pierrard (Vrije Universiteit Brussel), Rafael Salaberry (University of Texas at Austin), Suzanne Schlyter (Lund Universitet), Richard Towell (Salford University), and Daniel Véronique (Université d’Aix-en-Provence). We are very much indebted to that scientific committee for their insightful input at each step of the project. We are also thankful for the financial support of the Association for French Language Studies through its workshop grant, and to the Aston Modern Languages Research Foundation for funding the proofreading of the manuscript.
Resumo:
One of the key challenges that organizations face when trying to integrate knowledge across different functions is the need to overcome knowledge boundaries between team members. In cross-functional teams, these boundaries, associated with different knowledge backgrounds of people from various disciplines, create communication problems, necessitating team members to engage in complex cognitive processes when integrating knowledge toward a joint outcome. This research investigates the impact of syntactic, semantic, and pragmatic knowledge boundaries on a team’s ability to develop a transactive memory system (TMS)—a collective memory system for knowledge coordination in groups. Results from our survey show that syntactic and pragmatic knowledge boundaries negatively affect TMS development. These findings extend TMS theory beyond the information-processing view, which treats knowledge as an object that can be stored and retrieved, to the interpretive and practice-based views of knowledge, which recognize that knowledge (in particular specialized knowledge) is localized, situated, and embedded in practice.
Resumo:
In this paper we propose algorithms for combining and ranking answers from distributed heterogeneous data sources in the context of a multi-ontology Question Answering task. Our proposal includes a merging algorithm that aggregates, combines and filters ontology-based search results and three different ranking algorithms that sort the final answers according to different criteria such as popularity, confidence and semantic interpretation of results. An experimental evaluation on a large scale corpus indicates improvements in the quality of the search results with respect to a scenario where the merging and ranking algorithms were not applied. These collective methods for merging and ranking allow to answer questions that are distributed across ontologies, while at the same time, they can filter irrelevant answers, fuse similar answers together, and elicit the most accurate answer(s) to a question.
Resumo:
It is well established that speech, language and phonological skills are closely associated with literacy, and that children with a family risk of dyslexia (FRD) tend to show deficits in each of these areas in the preschool years. This paper examines what the relationships are between FRD and these skills, and whether deficits in speech, language and phonological processing fully account for the increased risk of dyslexia in children with FRD. One hundred and fifty-three 4-6-year-old children, 44 of whom had FRD, completed a battery of speech, language, phonology and literacy tasks. Word reading and spelling were retested 6 months later, and text reading accuracy and reading comprehension were tested 3 years later. The children with FRD were at increased risk of developing difficulties in reading accuracy, but not reading comprehension. Four groups were compared: good and poor readers with and without FRD. In most cases good readers outperformed poor readers regardless of family history, but there was an effect of family history on naming and nonword repetition regardless of literacy outcome, suggesting a role for speech production skills as an endophenotype of dyslexia. Phonological processing predicted spelling, while language predicted text reading accuracy and comprehension. FRD was a significant additional predictor of reading and spelling after controlling for speech production, language and phonological processing, suggesting that children with FRD show additional difficulties in literacy that cannot be fully explained in terms of their language and phonological skills. It is well established that speech, language and phonological skills are closely associated with literacy, and that children with a family risk of dyslexia (FRD) tend to show deficits in each of these areas in the preschool years. This paper examines what the relationships are between FRD and these skills, and whether deficits in speech, language and phonological processing fully account for the increased risk of dyslexia in children with FRD. One hundred and fifty-three 4-6-year-old children, 44 of whom had FRD, completed a battery of speech, language, phonology and literacy tasks. © 2014 John Wiley & Sons Ltd.
Resumo:
The semantic model developed in this research was in response to the difficulty a group of mathematics learners had with conventional mathematical language and their interpretation of mathematical constructs. In order to develop the model ideas from linguistics, psycholinguistics, cognitive psychology, formal languages and natural language processing were investigated. This investigation led to the identification of four main processes: the parsing process, syntactic processing, semantic processing and conceptual processing. The model showed the complex interdependency between these four processes and provided a theoretical framework in which the behaviour of the mathematics learner could be analysed. The model was then extended to include the use of technological artefacts into the learning process. To facilitate this aspect of the research, the theory of instrumentation was incorporated into the semantic model. The conclusion of this research was that although the cognitive processes were interdependent, they could develop at different rates until mastery of a topic was achieved. It also found that the introduction of a technological artefact into the learning environment introduced another layer of complexity, both in terms of the learning process and the underlying relationship between the four cognitive processes.
Resumo:
How do signals from the 2 eyes combine and interact? Our recent work has challenged earlier schemes in which monocular contrast signals are subject to square-law transduction followed by summation across eyes and binocular gain control. Much more successful was a new 'two-stage' model in which the initial transducer was almost linear and contrast gain control occurred both pre- and post-binocular summation. Here we extend that work by: (i) exploring the two-dimensional stimulus space (defined by left- and right-eye contrasts) more thoroughly, and (ii) performing contrast discrimination and contrast matching tasks for the same stimuli. Twenty-five base-stimuli made from 1 c/deg patches of horizontal grating, were defined by the factorial combination of 5 contrasts for the left eye (0.3-32%) with five contrasts for the right eye (0.3-32%). Other than in contrast, the gratings in the two eyes were identical. In a 2IFC discrimination task, the base-stimuli were masks (pedestals), where the contrast increment was presented to one eye only. In a matching task, the base-stimuli were standards to which observers matched the contrast of either a monocular or binocular test grating. In the model, discrimination depends on the local gradient of the observer's internal contrast-response function, while matching equates the magnitude (rather than gradient) of response to the test and standard. With all model parameters fixed by previous work, the two-stage model successfully predicted both the discrimination and the matching data and was much more successful than linear or quadratic binocular summation models. These results show that performance measures and perception (contrast discrimination and contrast matching) can be understood in the same theoretical framework for binocular contrast vision. © 2007 VSP.
Resumo:
The human visual system combines contrast information from the two eyes to produce a single cyclopean representation of the external world. This task requires both summation of congruent images and inhibition of incongruent images across the eyes. These processes were explored psychophysically using narrowband sinusoidal grating stimuli. Initial experiments focussed on binocular interactions within a single detecting mechanism, using contrast discrimination and contrast matching tasks. Consistent with previous findings, dichoptic presentation produced greater masking than monocular or binocular presentation. Four computational models were compared, two of which performed well on all data sets. Suppression between mechanisms was then investigated, using orthogonal and oblique stimuli. Two distinct suppressive pathways were identified, corresponding to monocular and dichoptic presentation. Both pathways impact prior to binocular summation of signals, and differ in their strengths, tuning, and response to adaptation, consistent with recent single-cell findings in cat. Strikingly, the magnitude of dichoptic masking was found to be spatiotemporally scale invariant, whereas monocular masking was dependent on stimulus speed. Interocular suppression was further explored using a novel manipulation, whereby stimuli were presented in dichoptic antiphase. Consistent with the predictions of a computational model, this produced weaker masking than in-phase presentation. This allowed the bandwidths of suppression to be measured without the complicating factor of additive combination of mask and test. Finally, contrast vision in strabismic amblyopia was investigated. Although amblyopes are generally believed to have impaired binocular vision, binocular summation was shown to be intact when stimuli were normalized for interocular sensitivity differences. An alternative account of amblyopia was developed, in which signals in the affected eye are subject to attenuation and additive noise prior to binocular combination.
Resumo:
Category-specific disorders are frequently explained by suggesting that living and non-living things are processed in separate subsystems (e.g. Caramazza & Shelton, 1998). If subsystems exist, there should be benefits for normal processing, beyond the influence of structural similarity. However, no previous study has separated the relative influences of similarity and semantic category. We created novel examples of living and non-living things so category and similarity could be manipulated independently. Pre-tests ensured that our images evoked appropriate semantic information and were matched for familiarity. Participants were trained to associate names with the images and then performed a name-verification task under two levels of time pressure. We found no significant advantage for living things alongside strong effects of similarity. Our results suggest that similarity rather than category is the key determinant of speed and accuracy in normal semantic processing. We discuss the implications of this finding for neuropsychological studies. © 2005 Psychology Press Ltd.