The concept of commitment has emerged recently in international business literature especially in explaining importer behaviour as a counterpart of the process of internationalisation. Importer commitment often plays a dominant role as one of the major factors influencing relationships in the exporter-importer dyad and facilitates the process of internationalisation by imparting access to the international market. This critical importer and supplier relationship and its animating factors are, however, overlooked and largely neglected in the literature. Accordingly, it is inconclusive as to which factors influence importer commitment and how they influence it. Drawing on the literature, this study strived to investigate the spectrum of importer commitment and has explicitly examined eight factors influencing importer commitment to a foreign supplier by integrating the factors in a comprehensive model. Cultural similarity between importer and overseas supplier, knowledge and experience of the importer, the supplier's competencies, communication between importer and supplier, the supplier's opportunism, the importer's trust, importer transaction-specific investment, and environmental volatility of the import market have been identified as possible antecedents of importer commitment. Theoretical foundations are drawn basically from transaction cost economics, internationalisation process theory and resource-based theory of the firm to design a basic framework for quantitative investigation. Further, the study endeavors to gain important insights into the phenomena related to the trust and commitment building process through qualitative in-depth interviews. In addition, to validate the qualitative reasoning, a competing quantitative model is developed where trust plays a mediating role for some of the predictor variables in the model. Primary data were collected from a sample of 232 industrial and commercial importers in a developing country for empirical verification of the quantitative models using Structural Equation Modeling. As reported in this thesis, the proposed model with minor modifications fit better with the data compared to the competing model, and it explained 56% of the variance of importer commitment. However, the analysis of the modified proposed structural model revealed that ten out of fourteen hypotheses are significant including five direct paths as antecedents of importer commitment. The mediating role of trust and opportunism in the model is also supported. Twelve interviews were conducted to add in-depth richer insights into the study for further verification of the knowledge development, and trust and commitment building process in the importer-supplier relationship. The findings support most conceptual links in the qualitative model and lend support to most of the hypothesised relationships in the modified competing quantitative model. These findings extend the application of the underpinned theories and their tenets in explaining the importersupplier commitment relationship and contribute to the body of knowledge. Implications of the findings are discussed and future research directions are recommended.

Η κατάλληλη οργάνωση του περιεχομένου ενός ιστοτόπου, έτσι ώστε να αυξάνεται η ευρεσιμότητα των πληροφοριών και να διευκολύνεται η επιτυχής ολοκλήρωση των τυπικών εργασιών των χρηστών, αποτελεί έναν από τους πρωταρχικούς στόχους των σχεδιαστών ιστοτόπων. Οι υπάρχουσες τεχνικές του πεδίου Αλληλεπίδρασης-Ανθρώπου Υπολογιστή που συνεισφέρουν στην επίτευξη αυτού του στόχου συχνά αγνοούνται εξαιτίας των απαιτήσεών τους σε χρονικούς και οικονομικούς πόρους. Ειδικότερα για ειδησεογραφικούς ιστοτόπους, τόσο το μέγεθος τους όσο και η καθημερινή προσθήκη και τροποποίηση των παρεχόμενων πληροφοριών, καθιστούν αναγκαία τη χρήση αποδοτικότερων τεχνικών για την οργάνωση του περιεχομένου τους. Στην εργασία αυτή διερευνούμε την αποτελεσματικότητα μίας μεθόδου, επονομαζόμενης AutoCardSorter, που έχει προταθεί στη βιβλιογραφία για την ημιαυτόματη κατηγοριοποίηση ιστοσελίδων, βάσει των σημασιολογικών συσχετίσεων του περιεχομένου τους, στο πλαίσιο οργάνωσης των πληροφοριών ειδησεογραφικών ιστοτόπων. Για το σκοπό αυτό διενεργήθηκαν πέντε συνολικά μελέτες, στις οποίες πραγματοποιήθηκε τόσο ποσοτική όσο και ποιοτική σύγκριση των κατηγοριοποιήσεων που προέκυψαν από συμμετέχοντες σε αντίστοιχες μελέτες ταξινόμησης καρτών ανοικτού και κλειστού τύπου, με τα αποτελέσματα της τεχνικής AutoCardSorter. Από την ανάλυση των αποτελεσμάτων προέκυψε ότι η AutoCardSorter παρήγαγε ομαδοποιήσεις άρθρων που βρίσκονται σε μεγάλη συμφωνία με αυτές των συμμετεχόντων στις μελέτες, αλλά με σημαντικά αποδοτικότερο τρόπο, επιβεβαιώνοντας προηγούμενες παρόμοιες μελέτες σε ιστοτόπους άλλων θεματικών κατηγοριών. Επιπρόσθετα, οι μελέτες έδειξαν ότι μία ελαφρώς τροποποιημένη εκδοχή της AutoCardSorter τοποθετεί νέα άρθρα σε προϋπάρχουσες κατηγορίες με αρκετά μικρότερο ποσοστό συμφωνίας συγκριτικά με τον τρόπο που επέλεξαν οι συμμετέχοντες. Η εργασία ολοκληρώνεται με την παρουσίαση κατευθύνσεων για την βελτίωση της αποτελεσματικότητας της AutoCardSorter, τόσο στο πλαίσιο οργάνωσης του περιεχομένου ειδησεογραφικών ιστοτόπων όσο και γενικότερα. / The proper structure of a website's content, so as to increase the findability of the information provided and to ease the typical user task-making, is one of the primary goals of website designers. The existing methods from the field of HCI that assist designers in this, are often neglected due to their high cost and human resources demanded. Even more so on News Sites, their size and the daily content updating call for improved and more efficient techniques. In this thesis we investigate the efficiency of a novel method, called AutoCardSorter, that has been suggested in bibliography for the semi-automatic content categorisation based on the semantic similarity of each webpage-content. To accomplish this we conducted five comparative studies in which the method was compared, to the primary alternatives of the classic Card Sorting method (open, closed). The analysis of the results showed that AutoCardSorter suggested article categories with high relavance to the ones suggested from a group of human subjects participating in the CardSort studies, although in a much more efficient way. This confirms the results of similar previous studies on websites of other themes (eg. travel, education). Moreover, the studies showed that a modified version of the method places articles under pre-existing categories with significant less relavance to the categorisation suggested by the participants. The thesis is concluded with the proposal of different ways to improve the proposed method's efficiency, both in the content of News Sites and in general.

Made available in DSpace on 2014-06-11T19:35:43Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-04-06Bitstream added on 2014-06-13T19:05:56Z : No. of bitstreams: 1 santos_tg_dr_rcla.pdf: 2207082 bytes, checksum: cd6f4211c558cc08a16cda8ec6665379 (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Estudamos a riqueza, composição taxonômica e os padrões de distribuição espaciais e temporais de taxocenoses de anuros do Parque Estadual Morro do Diabo (PEMD), o maior remanescente de Floresta Estacional Semidecídua no estado de São Paulo, Brasil. Registramos 28 espécies de anuros (Apêndice I) de setembro de 2005 a março de 2007, que compreenderam um misto de espécies de Mata Atlântica, do Cerrado e de formas amplamente distribuídas na América do Sul, geralmente consideradas tolerantes a modificações antropogênicas. A baixa riqueza de espécies e de modos reprodutivos, a predominância de espécies habitatgeneralistas e a alta similaridade de espécies de anuros com áreas de Cerrado podem ser explicadas pela sazonalidade climática da área estudada (estação seca pronunciada), além da grande distância em relação a centros de diversificação de anuros, como as montanhas costeiras da Floresta Atlântica úmida. Chuva e fotoperíodo explicaram aproximadamente 77% da atividade de vocalização de toda a taxocenose, enquanto somente a chuva e o fotoperíodo explicaram a temporada de vocalização em ambientes temporários e permanentes, respectivamente. Registramos alta sobreposição na temporada de vocalização dos machos, mas segregação na fase larval. A distribuição das espécies de anuros entre sítios de reprodução (Apêndice II) diferiu da esperada pelo acaso e compreendeu três taxocenoses distintas de anuros que foram explicadas pelo conjunto de variáveis ambientais de riachos permanentes, represas permanentes e poças temporárias. Registramos que 19 espécies de anuros (aproximadamente 83% da riqueza total de espécies registradas nos corpos d’água monitorados) foram indicadoras da heterogeneidade ambiental: três espécies indicaram riachos permanentes, quatro indicaram represas permanentes e 12 espécies indicaram poças temporárias... / We studied richness, composition, and patterns of temporal and spatial distributions of anuran assemblages of Morro do Diabo State Park (MDSP), the major remnant of Mesophytic Semideciduous Forest (MSF) in the state of São Paulo, Brazil. From September 2005 to March 2007 we recorded 28 anuran species (Appendix I), comprising a mix of Atlantic, Cerrado, and South American widespread species, usually considered tolerant to anthropic modifications. The low richness of species and reproductive modes, the predominance of habitat generalist species, and the high similarity with Cerrado areas can be explained by climatic seasonality of the studied area (pronounced dry season), besides its large distance in relation to centers of anuran diversification, such as coastal mountains of the wet Atlantic Forest. Rainfall and photoperiod explained about 77% of calling activity of the whole assemblage, while rainfall alone in temporary habitats and photoperiod in permanent ones explained the calling season. We recorded high temporal overlap for calling males, but segregation for tadpoles. Spatial distribution of anuran species among breeding sites of the MDSP (Appendix II) differed of expected by chance and comprised three distinct anuran assemblages that were explained by the suite environmental variables of permanent streams, permanent dams, and temporary ponds. We recorded that 19 species (about 83% of total anuran species recorded in monitored sites) were indicators of environmental heterogeneity: three anuran species indicated permanent streams, four indicated permanents dams, and 12 anuran species indicated temporary ponds. Regarding to micro-spatial distribution of anuran species at two temporary ponds of MDSP, we recorded that males of most pairs of species (96%) used distinct sites for calling activities. The best combination of variables discriminating anuran species regarding male... (Complete abstract click electronic access below)

Submitted by Johnny Rodrigues (johnnyrodrigues@ufcg.edu.br) on 2017-12-11T13:08:51Z No. of bitstreams: 1 DANIELLE CHAVES DE MEDEIROS - DISSERTAÇÃO PPGCC 2014.pdf: 1794393 bytes, checksum: 843f24f727881568e52ff59c12122403 (MD5) / Made available in DSpace on 2017-12-11T13:08:51Z (GMT). No. of bitstreams: 1 DANIELLE CHAVES DE MEDEIROS - DISSERTAÇÃO PPGCC 2014.pdf: 1794393 bytes, checksum: 843f24f727881568e52ff59c12122403 (MD5) Previous issue date: 2014-12 / A seleção de critérios para a análise de informações durante o processo de avaliação da participação em fóruns de discussão de cursos de Educação a Distância (EaD) é um grande desafio. São muitas as variáveis que devem ser consideradas neste processo, além da subjetividade inerente à análise realizada pelo docente, passível de erro humano. Os docentes geralmente não possuem a seu dispor todos os recursos necessários, se tornando necessário o uso de uma metodologia ou ferramenta que o auxilie no processo de avaliação. Diante desta demanda e, a partir de um estudo dos principais indicadores qualitativos/quantitativos utilizados pelos professores de EaD, foi desenvolvido um arcabouço para a análise da participação dos alunos em fóruns. O objetivo deste arcabouço é servir de apoio à tomada de decisão do professor, fornecendo um mecanismo mais efetivo para a mensuração da quantidade e da qualidade das interações, passível de adaptação à metodologia tradicional adotada por cada docente. A validação deste arcabouço deu-se a partir da administração de questionários para a sondagem da opinião de docentes atuantes na área de ensino a distância, assim como pela realização de estudos de caso envolvendo a avaliação da acurácia de instâncias do arcabouço para o cálculo da nota de participação de alunos. Foi desenvolvido um Sistema Especialista (SE) para o processamento dos dados, com o uso de funções de similaridade para realizar, de forma semiautomática, a avaliação do conteúdo das mensagens dos alunos. Assim, as notas de participação calculadas foram confrontadas com as notas atribuídas pelo docente utilizando a abordagem tradicional. Os resultados obtidos demonstraram que, em três das cinco turmas observadas, não foi possível verificar a existência de diferenças estatísticas significativas entre o desempenho das abordagens estudadas. Um estudo da acurácia e correlação revela que, em todos os casos analisados, há uma forte relação entre os dados e o erro médio encontrado foi inferior a 3%, demonstrando a aplicabilidade do arcabouço ao contexto da avaliação da participação em fóruns. / The selection of criteria for the information analysis during the participation evaluation process, in discussion forums of distance courses, is a major challenge. There are many variables to consider in this process, in addition to the subjectivity inherent in the analysis carried out by the instructor, which is subject to human error. Instructors, generally, do not have at their disposal all the resources necessary, thus, the use of methodologies or tools that can help them with this process are necessary. Facing this demand, and after performing a study of the major qualitative/quantitative indicators used by distance education teachers, we developed a framework for the analysis of the student participation in the forums. The aim of this framework is to support the decision-making process, by providing a more effective mechanism to measure the quantity and quality of interactions, capable of adjusting itself to the traditional methodology adopted by each teacher. The validation of this framework was performed by the administration of questionnaires that surveyed the opinion of active teachers in the distance learning area, and by the execution of case studies involving the assessment of the accuracy of instances of this framework for calculating the participation grade of students. The study involved the development of an Expert System, for the treatment and processing of the data, using similarity functions to perform, semi-automatically, the assessment of the content of the students' messages. Thus, it was possible to confront the calculated participation grades with the grades assigned by the teacher using the traditional approach. The results showed that, in three out of the five classes observed, it was not possible to verify the existence of statistically significant differences between the performance of both the approaches studied. A study of the accuracy and correlation shows that, in all the cases analyzed, there is a strong relationship between the data, and the average error was less than 3%, demonstrating the applicability of the proposed framework to the assessment of student participation in forums.

Submitted by Alison Vanceto (alison-vanceto@hotmail.com) on 2017-08-08T17:30:10Z No. of bitstreams: 1 DissCGA.pdf: 1377116 bytes, checksum: eeaa4d5429ed9fe1aeac6a215d0acc52 (MD5) / Approved for entry into archive by Ronildo Prado (ronisp@ufscar.br) on 2017-08-09T14:09:22Z (GMT) No. of bitstreams: 1 DissCGA.pdf: 1377116 bytes, checksum: eeaa4d5429ed9fe1aeac6a215d0acc52 (MD5) / Approved for entry into archive by Ronildo Prado (ronisp@ufscar.br) on 2017-08-09T14:09:30Z (GMT) No. of bitstreams: 1 DissCGA.pdf: 1377116 bytes, checksum: eeaa4d5429ed9fe1aeac6a215d0acc52 (MD5) / Made available in DSpace on 2017-08-09T14:17:28Z (GMT). No. of bitstreams: 1 DissCGA.pdf: 1377116 bytes, checksum: eeaa4d5429ed9fe1aeac6a215d0acc52 (MD5) Previous issue date: 2017-02-13 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / In several research areas, interviews are a means of obtaining data widely used by researchers. These interviews are arranged, in most cases, in several documents and have an informal language, because they are conversations between several people at the same time. Analyzing such documents is an arduous and time-consuming task, bringing fatigue and difficulties to a correct analysis. One solution for analyzing this type of interview is to group documents according to the similarity between them, so that experts can analyze documents of similar subjects more quickly. In this way, this work presents the method SOM4SImD, created to detect the semantic similarity between the documents composed by interviews with an informal language written in Brazilian Portuguese. In order to create this method, an ontology of the same document domain was used, which allowed the use of the formal terms of the ontology, along with its synonyms and variants, to perform the semantic annotation in the documents and to calculate the similarity between the interview pairs. Through the created method, a SimIGroup approach was developed that assists the researchers in the qualitative analysis of the documents, using Coding technique. The results show that the SOM4SImD method and the SimIGroup approach reduce the difficulties and fatigue in the analysis of the documents made by the annotators, helping to increase the number of documents analyzed. In addition, the SOM4SImD method was more advantageous in obtaining similarity between documents than the others found in the literature, reaching significant values for the performance measures, with 0.96 accuracy, 0.93 of recall and 0.94 of F-Mensure. / Em diversas áreas de pesquisas, as entrevistas são um meio de obtenção de dados muito utilizadas por pesquisadores. Essas entrevistas são dispostas, na maioria das vezes, em diversos documentos e têm uma linguagem informal, por se tratar de conversas entre várias pessoas ao mesmo tempo. Analisar tais documentos é uma tarefa árdua e demorada, trazendo cansaço e dificuldades para uma análise correta. Uma solução para análise desse tipo de entrevistas é agrupar os documentos de acordo com a similaridade que existem entre eles, pois assim os especialistas conseguem analisar os documentos de assuntos parecidos de forma mais rápida. Desta forma, este trabalho apresenta o método SOM4SImD, criado para detectar a similaridade semântica entre os documentos compostos por entrevistas com uma linguagem informal escritas no português brasileiro. Para criar este método, foi utilizado uma ontologia de mesmo domínio dos documentos, que permitiu o uso dos termos formais da ontologia, juntamente com seus sinônimos e variantes para realizar a anotação semântica nos documentos e para realizar o cálculo da similaridade entre os pares de entrevistas. Através do método criado, foi desenvolvida uma abordagem SimIGroup que auxilia os pesquisadores na análise qualitativa dos documentos, utilizando a técnica Coding. Os resultados mostram que o método SOM4SImD e a abordagem SimIGroup diminuem as dificuldades e cansaço na análise dos documentos realizadas pelos anotadores, auxiliando no aumento da quantidade de documentos analisados. Além disso, o método SOM4SImD se mostrou mais vantajoso na obtenção de similaridade entre documentos do que os demais encontrados na literatura, alcançando valores significantes para as medidas de desempenho, com 0,96 de precisão, 0,93 de revocação e 0,94 de F-Mensure.

Submitted by Maria Medeiros (maria.dilva1@ufcg.edu.br) on 2018-06-05T14:49:44Z No. of bitstreams: 1 ALEX SANDRO DA CUNHA RÊGO - TESE (PPGCC) 2016.pdf: 1783053 bytes, checksum: 4ae3b5d42dde739cfd57afaa25fd7e63 (MD5) / Made available in DSpace on 2018-06-05T14:49:44Z (GMT). No. of bitstreams: 1 ALEX SANDRO DA CUNHA RÊGO - TESE (PPGCC) 2016.pdf: 1783053 bytes, checksum: 4ae3b5d42dde739cfd57afaa25fd7e63 (MD5) Previous issue date: 2016 / As folksonomias têm despontado como ferramentas úteis de gerenciamento online de conteúdo digital. A exemplo dos populares websites Delicious, Flickr e BibSonomy, diariamente os usuários utilizam esses sistemas para efetuar upload de recursos web (e.g., url, fotos, vídeos e referências bibliográficas) e categorizá-los por meio de tags. A ausência de relações semânticas do tipo sinonímia e hiperonímia/hiponímia no espaço de tags das folksonomias reduz a capacidade do usuário de encontrar recursos relevantes. Para mitigar esse problema, muitos trabalhos de pesquisa se apoiam na aplicação de medidas de similaridade para detecção de sinonímia e construção automática de hierarquias de tags por meio de algoritmos heurísticos. Nesta tese de doutorado, o problema de detecção de sinonímia e hiperonímia/hiponímia entre pares de tags é modelado como um problema de classificação em Aprendizado de Máquina. A partir da literatura, várias medidas de similaridade consideradas boas indicadoras de sinonímia e hiperonímia/hiponímia foram identificadas e empregadas como atributos de aprendizagem. A incidência de um severo desbalanceamento e sobreposição de classes motivou a investigação de técnicas de balanceamento para superar ambos os problemas. Resultados experimentais usando dados reais das folksonomias BibSonomy e Delicious mostraram que a abordagem proposta denominada CPDST supera em termos de acurácia o baseline de melhor desempenho nas tarefas de detecção de sinonímia e hiperonímia/hiponímia. Também, aplicou-se a abordagem CPDST no contexto de geração de listas de tags semanticamente relacionadas, com o intuito de prover acesso a recursos adicionais anotados com outros conceitos pertencentes ao domínio da busca. Além da abordagem CPDST, foram propostos dois algoritmos fundamentados no acesso ao WordNet e ConceptNet para sugestão de listas especializadas com tags sinônimas e hipônimas. O resultado de uma avaliação quantitativa demonstrou que a abordagem CPDST provê listas de tags relevantes em relação às listas providas pelos métodos comparados. / Folksonomies have emerged as useful tools for online management of digital content. Popular websites as Delicious, Flickr and BibSonomy are now widespread with thousands of users using them daily to upload digital content (e.g., webpages, photos, videos and bibliographic information) and tagging for later retrieval. The lack of semantic relations such as synonym and hypernym/hyponym in the tag space may diminish the ability of users in finding relevant resources. Many research works in the literature employ similarity measures to detect synonymy and to build hierarchies of tags automatically by means of heuristic algorithms. In this thesis, the problems of synonym and subsumption detection between pairs of tags are cast as a pairwise classification problem. From the literature, several similarity measures that are good indicators of synonymy and subsumption were identified, which are used as learning features. Under this setting, there is a severe class imbalance and class overlapping which motivated us to investigate and employ class imbalance techniques to overcome these problems. A comprehensive set of experiments were conducted on two large real-world datasets of BibSonomy and Delicious systems, showing that the proposed approach named CPDST outperforms the best performing heuristic-based baseline in the tasks of synonym and subsumption detection. CPDST is also applied in the context of tag list generation for providing access to additional resources annotated with other semantically related tags. Besides CPDST approach, two algorithms based on WordNet and ConceptNet accesses are proposed for capturing specifically synonyms and hyponyms. The outcome of an evaluative quantitative analysis showed that CPDST approach yields relevant tag lists in relation to the produced ones by the compared methods.

Ce travail porte sur l'estimation des indices d'autosimilarité et de stabilité d'un processus ou champ stable fractionnaire et autosimilaire ou d'un processus stable multifractionnaire.Plus précisément, soit X un processus ou un champ stable H-autosimilaire à accroissements stationnaires (H-sssi) ou un processus stable multifractionnaire. Nous observons X aux points k/n, k=0,..., n.Nos estimations sont basées sur des variations de puissances négatives beta avec -1/2<beta<0: en effet, ces variations ont une espérance et une variance.Nous obtenons des estimateurs consistants, avec les vitesses de convergence, pour plusieurs processus H-sssi alpha-stables classiques (mouvement brownien fractionnaire, mouvement stable fractionnaire linéaire, processus de Takenaka, movement de Lévy).De plus, nous obtenons la normalité asymptotique de nos estimations pour le mouvement brownien fractionnaire et le mouvement de Lévy.Ce nouveau cadre nous permet de donner une estimation pour le paramètre d'autosimilarité H sans hypothèse sur alpha et, vice versa, nous pouvons estimer l'indice stable alpha sans hypothèse sur H.En généralisant, pour le cas d'une dimension supérieure à 1, nous obtenons également des estimateurs consistants pour H et alpha. Les résutats sont illustrés par des exemples: champ de Lévy fractionnaire, champ stable fractionnaire linéaire, champ de Takenaka.Pour les processus stables multifractionnaires, nous nous concentrons sur le mouvement brownien multifractionnaire et le processus stable multifractionnaire linéaire. Dans ces deux cas, nous obtenons la consistance des estimateurs pour la fonction d'autosimilarité à un temps donné u et pour l'indice stable alpha. / This work is concerned with the estimation of the self-similarity and the stability indices of a H-self-similarity stable process (field) or a multifractional stable process.More precisely, let X be a H-sssi (self-similar stationary increments) symmetric alpha-stable process (field) or a multifractional stable process. We observe X at points k/n, k=0,...,n.Our estimates are based on beta-negative power variations with -1/2<beta<0, thanks to the existence of expectations and covariances of these variations.We get consistent estimators, with rates of convergence, for several classical H-sssi alpha-stable processes(fractional Brownian motion, well-balanced linear fractional stable motion, Takenaka's processes, Lévy motion). Moreover, we get asymptotic normality of our estimates for fractional Brownian motion and Lévy motion.This new framework allows us to give an estimator for the self-similarity parameter H without assumptions on alpha and, vice versa, we can estimate the stable index alpha without assumptions on H.Generalizing for the case of high dimensions, we also obtain consistent estimators for H and alpha. The results are illustrated with some familiar examples: Lévy fractional Brownian field, well-balanced linear fractional stable field and Takenaka random field.For multifractional stable process, we concentrate on multifractional Brownian motion and linear multifractional stable process. In these two cases, we get the consistency of the estimators for the value of self-similarity function H at a fixed time u and for the stability index alpha.

La recherche d'information dans des masses de données multimédia et l'indexation de ces grandes bases d'images par le contenu sont des problématiques très actuelles. Elles s'inscrivent dans un type de gestion de données qu'on appelle le Digital Asset Management (ou DAM) ; Le DAM fait appel à des techniques de segmentation d'images et de classification de données. Nos principales contributions dans cette thèse peuvent se résumer en trois points :- Analyse des utilisations possibles des différentes méthodes d'extraction des caractéristiques locales en exploitant la technique de VLAD.- Proposition d'une nouvelle méthode d'extraction de l'information relative à la couleur dominante dans une image.- Comparaison des Machine à Supports de Vecteur (SVM - Support Vector Machine) à différents classifieurs pour la proposition de mots clés d'indexation. Ces contributions ont été testées et validées sur des données de synthèse et sur des données réelles. Nos méthodes ont alors été largement utilisées dans le système DAM ePhoto développé par la société EINDEN, qui a financé la thèse CIFRE dans le cadre de laquelle ce travail a été effectué. Les résultats sont encourageants et ouvrent de nouvelles perspectives de recherche. / The search for information in masses of multimedia data and the indexing of these large databases by the content are very current problems. They are part of a type of data management called Digital Asset Management (or DAM) ; The DAM uses image segmentation and data classification techniques.Our main contributions in this thesis can be summarized in three points : - Analysis of the possible uses of different methods of extraction of local characteristics using the VLAD technique.- Proposed a new method for extracting dominant color information in an image.- Comparison of Support Vector Machines (SVM) to different classifiers for the proposed indexing keywords. These contributions have been tested and validated on summary data and on actual data. Our methods were then widely used in the DAM ePhoto system developed by the company EINDEN, which financed the CIFRE thesis in which this work was carried out. The results are encouraging and open new perspectives for research.

L'objectif principal de cette thèse est d'étudier les conséquences du bilinguisme sur la production de la parole. Des recherches antérieures ont montré que les locuteurs bilingues montrent un coût par rapport aux monolingues dans différentes expériences linguistiques. Nous avons étudié les origines du coût bilingue en explorant l'influence de variables spécifiques comme la similitude phonologique. En outre, nous avons examiné la portée du coût bilingue en évaluant des durées articulatoires de la parole et la production de groupes nominaux. Nous rapportons que l'augmentation de la similarité phonologique entre les mots d'une même langue ralentit la parole, alors que l'augmentation de la similarité phonologique entre les langues aide les bilingues à surmonter le coût bilingue. En outre, nos résultats ont montré que le coût bilingue se généralise aux phases articulatoires et à la production de groupes nominaux. Cette thèse fournit de nouvelles données sur le traitement de la parole pendant les stades phonologiques et articulatoires chez les locuteurs mono- et bilingues, et étend notre connaissance sur le coût bilingue en production de parole. / The main objective of this dissertation is to examine the consequences of bilingualism on speech production. Previous research has shown that bilingual speakers experience a cost compared to monolinguals in a variety of linguistic experiments. We investigated the origins of the bilingual cost by exploring influences of particular variables such as phonological similarity. Moreover, we investigated the scope of the bilingual cost by assessing speech performance, focusing on articulatory durations and noun-phrase production. We provide evidence that increased phonological similarity among words within one language slows speech, whereas increased phonological similarity across translations helps bilinguals to overcome the bilingual cost. In addition, our results show that the bilingual cost generalizes to articulatory durations and noun-phrase production. The current dissertation provides a more specific understanding of speech processing at phonological and articulatory stages in mono- and bilinguals, and extends our knowledge on the bilingual cost in speech production. / El objetivo principal de esta tesis es examinar las consecuencias del bilingüismo en la producción del habla. Estudios anteriores han demostrado que los hablantes bilingües presentan una mayor dificultad que los monolingües durante la realización de diferentes experimentos lingüísticos. Investigamos los orígenes del coste del bilingüismo, explorando los efectos de variables como la similitud fonológica. Además, investigamos el alcance del coste, evaluando las duraciones articulatorias durante el habla y la producción de sintagmas nominales. Mostramos que una mayor similitud fonológica entre palabras de una lengua ralentiza el habla, mientras que una mayor similitud entre traducciones ayudó a los bilingües a superar el coste. Finalmente, demostramos que el coste bilingüe se extiende a las duraciones articulatorias y a la producción de sintagmas nominales. Esta tesis aporta nuevas evidencias acerca del efecto que la similitud fonológica tiene sobre la producción del habla y proporciona un conocimiento más específico sobre cómo el bilingüismo influye durante las últimas fases del procesamiento del habla.

The performance of similarity search in the unstructured databases largely depends on the employed similarity model. The properties of metric space model enable indexing the data with metric access methods efficiently. But for unconstrained or nonmetric similarity models typical for multimedia, medical, or scientific databases, in which metric postulates do not hold, there exists no general solution so far. Motivated by the successful application of Ptolemaic indexing to the image retrieval, we introduce SIMDEX Framework which is a universal framework that is capable of revealing alternative indexing methods that will serve for efficient yet effective similarity searching for any similarity model. It explores the axiom space in order to discover novel techniques suitable for database indexing. We review all existing variants (simple I-SIMDEX; GP-SIMDEX and PGP-SIMDEX which both use genetic programming) and we outline how the different groups of domain researchers can benefit from them. We also describe a real application of SIMDEX Framework to practice while building the Smart Pivot Table indexing method together with advanced Triangle+ filtering for metric spaces empowered by LowerBound Tightening technique. At all cases, we provide extensive experimental evaluations of mentioned techniques. Powered by...