L'objectif général de cette thèse est d'examiner le lien entre les traits de personnalité évalués selon l'approche des cinq facteurs et les résultats des traitements psychosociaux auprès de jeunes adultes présentant un premier épisode psychotique. Afin d'atteindre cet objectif, 129 personnes ont été recrutées à participer à une étude expérimentale randomisée. Les participants ont été assignés soit à un groupe de thérapie cognitive-comportementale, soit à un groupe d'entraînement aux habiletés sociales visant la gestion des symptômes, soit à une liste d'attente. Les participants ont complété pré- et post-traitement le Questionnaire bref de personnalité NEO Révisé (Costa & McCrae, 1992), l'Échelle abrégée d'évaluation psychiatrique (Lukoff et al., 1986; Ventura et al., 1993) et l'Échelle d'adaptation cybernétique (Edwards & Baglioni, 1993). Dans le premier article, les profils de personnalité et la stabilité temporelle des traits de personnalité des jeunes adultes présentant un premier épisode psychotique ont été étudiés. Les résultats révèlent différents profils de personnalité et une stabilité des traits de personnalité. Dans le second article, les profils de personnalité et la valeur prédictive des traits de personnalité ou des profils sur les résultats thérapeutiques ont été investigués. Les résultats révèlent aussi différents profils de personnalité, aucun spécifiquement lié aux symptômes. Aucun lien n'a pu être rapporté entre les traits de personnalité et l'amélioration symptomatologique. Toutefois, les traits de personnalité et les profils sont liés à l'amélioration des stratégies actives d'adaptation. Dans le dernier article, la valeur prédictive des traits de personnalité sur les résultats thérapeutiques selon le groupe de traitement spécifique a été étudiée. Les résultats démontrent un lien entre les traits de personnalité et l'amélioration symptomatologique et des stratégies d'adaptation selon le traitement. Les traits de personnalité sont particulièrement liés aux résultats thérapeutiques des stratégies actives d'adaptation. Cette thèse contribue à l'avancement des connaissances en se penchant sur l'importance des traits de personnalité dans le traitement psychosocial des jeunes adultes présentant un premier épisode psychotique et en soulignant la nécessité d'étudier davantage les différences individuelles de la personnalité de cette clientèle. Les implications cliniques des résultats et les recommandations pour la recherche sont présentées. / The aim of this thesis was to elucidate the link between personality traits based on the Five Factor Model of personality and therapeutic outcomes of two group treatments for first episode psychosis: cognitive behavior therapy and skills training for symptom management. One hundred and twenty-nine individuals with first episode psychosis were recruited to participate in a randomized controlled trial. Participants were randomized to one of two group treatments or to a wait-list control group. Measures pre- and post-treatment included the shorter version of the Revised NEO personality Inventory (Costa & McCrae, 1992), measures of Brief Psychiatric Rating Scale-Expanded (Lukoff et al., 1986; Ventura et al., 1993) and the shorter version of the Cybernetic Coping Scale coping strategies (Edwards & Baglioni, 1993). In the first article, personality profiles and stability over time of personality traits of individuals with a first episode of psychosis were investigated. Results showed that individuals with a first episode of psychosis present with different personality profiles. Moreover, personality traits of the first episodes showed stability over time. In the second article, personality profiles and predictive value of personality traits or profiles on therapeutic outcomes of treatments for first episode psychosis were investigated. Results revealed also different personality profiles, none specifically linked to psychotic symptoms. No links could be demonstrated between personality traits and symptom improvements but personality traits and profiles were linked to therapeutic improvements in active coping strategies. In the last article, predictive value of personality traits on therapeutic outcomes accordingly to specific group treatments for first episode psychosis was investigated. Results showed links between personality traits, symptoms and coping outcome measures, according to specific group treatments. Personality traits were particularly linked to therapeutic improvements in active coping strategies. In sum, this thesis contributed to the field of personality traits in those with a first episode psychosis by investigating the pertinence of personality traits in the choice of psychosocial treatments and highlighting the need for further study considering individual differences in psychosis. Clinical implications are discussed and recommendations for clinical research offered.

La campylobactériose représente la principale cause de gastro-entérite bactérienne dans les pays industrialisés. L’épidémiologie de la maladie est complexe, impliquant plusieurs sources et voies de transmission. L’objectif principal de ce projet était d’étudier les facteurs environnementaux impliqués dans le risque de campylobactériose et les aspects méthodologiques pertinents à cette problématique à partir des cas humains déclarés au Québec (Canada) entre 1996 et 2006. Un schéma conceptuel des sources et voies de transmission de Campylobacter a d’abord été proposé suivant une synthèse des connaissances épidémiologiques tirées d’une revue de littérature extensive. Le risque d’une récurrence de campylobactériose a ensuite été décrit selon les caractéristiques des patients à partir de tables de survie et de modèles de régression logistique. Comparativement au risque de campylobactériose dans la population générale, le risque d’un épisode récurrent était plus élevé pour les quatre années suivant un épisode. Ce risque était similaire entre les genres, mais plus élevé pour les personnes de régions rurales et plus faible pour les enfants de moins de quatre ans. Ces résultats suggèrent une absence d’immunité durable ou de résilience clinique suivant un épisode déclaré et/ou une ré-exposition périodique. L’objectif suivant portait sur le choix de l’unité géographique dans les études écologiques. Neuf critères mesurables ont été proposés, couvrant la pertinence biologique, la communicabilité, l’accès aux données, la distribution des variables d’exposition, des cas et de la population, ainsi que la forme de l’unité. Ces critères ont été appliqués à des unités géographiques dérivées de cadre administratif, sanitaire ou naturel. La municipalité affichait la meilleure performance, étant donné les objectifs spécifiques considérés. Les associations entre l’incidence de campylobactériose et diverses variables (densité de volailles, densité de ruminants, abattoirs, température, précipitations, densité de population, pourcentage de diplomation) ont ensuite été comparées pour sept unités géographiques différentes en utilisant des modèles conditionnels autorégressifs. Le nombre de variables statistiquement significatives variait selon le degré d’agrégation, mais la direction des associations était constante. Les unités plus agrégées tendaient à démontrer des forces d’association plus élevées, mais plus variables, à l’exception de l’abattoir. Cette étude a souligné l’importance du choix de l’unité géographique d’analyse lors d’une utilisation d’un devis d’étude écologique. Finalement, les associations entre l’incidence de campylobactériose et des caractéristiques environnementales ont été décrites selon quatre groupes d’âge et deux périodes saisonnières d’après une étude écologique. Un modèle de Poisson multi-niveau a été utilisé pour la modélisation, avec la municipalité comme unité. Une densité de ruminant élevée était positivement associée avec l’incidence de campylobactériose, avec une force d’association diminuant selon l’âge. Une densité de volailles élevée et la présence d’un abattoir de volailles à fort volume d’abattage étaient également associées à une incidence plus élevée, mais seulement pour les personnes de 16 à 34 ans. Des associations ont également été détectées avec la densité de population et les précipitations. À l’exception de la densité de population, les associations étaient constantes entre les périodes saisonnières. Un contact étroit avec les animaux de ferme explique le plus vraisemblablement les associations trouvées. La spécificité d’âge et de saison devrait être considérée dans les études futures sur la campylobactériose et dans l’élaboration de mesures préventives. / Campylobacteriosis is a leading cause of acute bacterial gastro-enteritis in industrialized countries. The epidemiology of the disease is complex, involving many sources and transmission pathways. The principal objective of this project was to study environmental factors and methodological aspects pertinent to the spatial epidemiology of human campylobacteriosis using cases reported in Quebec (Canada) between 1996 and 2006. A conceptual diagram of sources and transmission pathways of Campylobacter was first proposed following a synthesis of current epidemiological knowledge based on a comprehensive literature review. The risk of recurrent episodes in relation to patient characteristics was described. Life table estimates and logistic regression were used for modeling. Compared to campylobacteriosis risk in the general population, the risk for a recurrent disease event was higher for a period of four years with a decreasing trend. This increased risk was similar across gender but higher for people from rural areas and lower for children under four years old. These results may suggest the absence of durable immunity or clinical resilience following a first episode and/or periodic re-exposure, at least among reported cases. Next, criteria were proposed and applied to ascertain the best geographical unit to use. Nine measurable criteria were proposed, including biological relevance, communicability of results, ease of data access, distribution of exposure variables, cases and population, and unit shape. These criteria were applied to various geographical units derived from administrative, health services and natural frameworks. Ultimately, the municipal geographical unit performed the best, given the specific objectives of the study. Future research areas for optimizing the choice of geographical unit were discussed. Another objective was to estimate and compare the associations between incidence and various environmental characteristics (poultry density, ruminant density, slaughterhouse, temperature, and precipitation) and demographic characteristics (population density, diploma) using seven different geographical units. Conditional autoregressive models were used for statistical modeling. In general, the number of significant predictors decreased as the aggregation level increased but directions of associations were consistent. More aggregated scales tended to show larger but more variable estimates for all variables, with the exception of the presence of slaughterhouses. This study highlighted the need for careful selection and analysis of geographical units when using ecological designs in epidemiological studies. Finally, the association between environmental characteristics and incidence in relation to four age groups and deux seasonal periods was studied. A multi-level Poisson regression model was used for modeling at the municipal level. High ruminant density was positively associated with incidence but decreased with age. High poultry density and presence of a large poultry slaughterhouse were also associated with higher incidence for people aged 16-34. Associations were also detected with population density and average daily precipitation. Except for population density, associations were constant across seasonal periods. Close contact with farm animals is most likely involved in the associations observed. Clearly, age and season must be considered in future studies on campylobacteriosis and in the design of preventive measures.

De nos jours, l’idée selon laquelle bon nombre d’individus atteints de psychose peuvent se rétablir sensiblement au fil du temps est de plus en plus répandue. Alors que le milieu médical associe le rétablissement à la rémission symptomatique, les usagers de services en santé mentale le voient plutôt comme un processus où l’absence de symptômes n’est pas une condition sine qua non. Ne s’opposant à ni l’un ni l’autre de ces points de vue, le traitement actuel des psychoses vise le retour à un fonctionnement social approprié. Chez les jeunes atteints d’un premier épisode psychotique, une diminution marquée des symptômes après un traitement pharmacologique se traduit rarement en une amélioration significative du fonctionnement, ce qui justifie la mise en place d’interventions psychosociales. On connait aujourd’hui quelques variables associées au fonctionnement social chez cette population, mais celui-ci a peu été étudié de façon spécifique. De même, on connait mal la manière dont ces jeunes vivent leur rétablissement en tant que processus. Cette thèse porte donc sur le rétablissement et le fonctionnement social de jeunes en début de psychose. La première partie consiste en une introduction aux concepts de rétablissement et de réadaptation, et en une revue de la littérature des interventions psychosociales pouvant favoriser leurs rétablissement et fonctionnement. Plus spécifiquement, nous illustrons comment ces interventions peuvent s’appliquer aux adolescents, clientèle sur laquelle peu de littérature existe actuellement. La deuxième partie présente les résultats d’une étude sur la valeur prédictive de variables sur trois domaines du fonctionnement social de 88 jeunes adultes en début de psychose. Des équations de régression multiple ont révélé qu’un niveau plus élevé de dépression était associé à une vie sociale moins active, qu’un moins bon apprentissage verbal à court terme était associé à un plus bas fonctionnement vocationnel, que le fait d’être de sexe masculin était négativement associé aux habiletés de vie autonome, et qu’un niveau plus élevé de symptômes négatifs prédisait de moins bonnes performances dans les trois sphères du fonctionnement. Finalement, la troisième partie s’intéresse au processus de rétablissement en début de psychose par l’analyse de récits narratifs selon un modèle en cinq stades. Nous avons découvert que l’ensemble de notre échantillon de 47 participants se situaient dans les deux premiers stades de rétablissement lors du premier temps de mesure, et que le fait de se trouver au deuxième stade était associé à de meilleurs scores d’engagement social et de fonctionnement occupationnel, à un meilleur développement narratif, à moins de symptômes négatifs et positifs, et à plus d’années de scolarité. Par ailleurs, l’examen des stades à deux autres temps de mesure a révélé des profils relativement stables sur une période de neuf mois. En somme, les résultats démontrent la nécessité d’évaluer le fonctionnement social de façon plus spécifique et l’importance d’offrir des interventions psychosociales en début de psychose visant notamment le développement des relations et l’intégration scolaire/professionnelle, ou visant à améliorer le faible développement narratif. Cette thèse est, de plus, un premier pas dans l’étude du processus de rétablissement des jeunes atteints de psychose. / Currently, the idea that several individuals experiencing psychosis can show evidence of recovery over time is gaining in popularity. Although recovery is viewed as the disappearance of symptoms in the medical field, consumers of mental health services see it more as process in which the complete absence of symptoms is not a sine qua non. Nevertheless, the current treatment for psychosis is aimed at regaining a satisfactory level of social functioning. In individuals experiencing a first psychotic episode, a noticeable decrease in symptoms is rarely associated with a significant improvement in functioning. Therefore, psychosocial interventions are necessary to assist in recovery. The literature has identified a number of variables associated with social functioning in this population, but to date, there are no studies investigating this aspect in details. Furthermore, very little is known about how these youth experience the process of recovery. This thesis dissertation will therefore address recovery and social functioning in young people experiencing a first episode of psychosis. A first section will serve as an introduction to the concepts of recovery and rehabilitation and a review of the literature on psychosocial interventions promoting recovery and functioning. Specifically, we will illustrate how these interventions can apply to adolescents, a population for which very few studies have been published. A second section will present the results of a study on the predictive value of variables on three domains of social functioning in 88 young adults in early psychosis. Multiple regression analyses showed that a more severe depression was associated with a less active social life; that a poorer short term verbal learning ability was associated with poorer vocational functioning; and that men showed poorer independent living skills. Furthermore, more severe negative symptoms were associated with poorer performances in all three spheres of social functioning. Finally, the third section will address the recovery process in early psychosis through the analysis of narratives using a five stage recovery model. We determined that overall, our sample of 47 individuals were classified within the first two stages of recovery at baseline and that those classified in the second stage showed better social engagement and vocational functioning scores, a better narrative development, less severe positive and negative symptoms, and had attained a higher educational level. Furthermore, the analysis of the stages of recovery across two others time points show that these profiles are relatively stable over a 9 month period. In conclusion, these results show that it is necessary to evaluate social functioning in a more detailed manner, and reaffirms the importance of making psychosocial interventions available to service users experiencing early psychosis. It highlights, in particular, the need for services aimed towards the development of social relationships and educational/vocational integration, or interventions addressing deficits in narrative development. Moreover, this thesis dissertation is a first step towards the study of the recovery process of young adults experiencing psychosis.

No description available.

Le vertige (V), l'étourdissement (E) et l'instabilité (I) sont des symptômes fréquents, traditionnellement considérés comme ayant des étiologies vestibulaires et extra-vestibulaires différentes. La prévalence de chaque symptôme et la manière dont ils sont liés entre eux ainsi qu'avec la migraine, l'agoraphobie, la susceptibilité au mal des transports (SMT), le malaise vagal (MV), l'anxiété/dépression (AD) et la prise de médicaments, ont été l'objet de cette étude. Un questionnaire auto-administré a été complété par 2897 adultes de la population lorraine, âgés de 18 à 86 ans, dont 1471 femmes. La prévalence sur un an du V était de 48,3%, celle de l'I de 39,1% et celle de l'E de 35,6%. Les VEI étaient corrélés entre eux et apparaissaient en général en diverses combinaisons (69,4%) ; 90% des épisodes de VEI avaient une durée inférieure ou égale à 2 mn et une fréquence < 1/mois. Les trois symptômes étaient similaires concernant leur prédominance féminine, le profil temporaire des épisodes et le lien avec les chutes et les nausées. Les VEI augmentaient avec le nombre de médicaments indépendamment de l'âge. Chaque VEI était corrélé avec chaque co-morbidité. Les facteurs de risque étaient pour l'agoraphobie : AD>sexe féminin>VEI, pour la SMT : sexe féminin > AD > migraine. En ajustant sur les trois VEI entre eux, le V reste un facteur de risque significatif pour chaque co-morbidité, suggérant que le V est un symptôme aussi peu spécifique que les deux autres et que les VEI représentent un spectre de symptômes résultant de diverses causes / Vertigo (V), dizziness (D) and unsteadiness (U) are common symptoms traditionally considered to result from different kinds of vestibular and non-vestibular dysfunctions. The prevalence of each symptom and how they relate to each other and to migraine, agoraphobia, motion sickness susceptibility (MSS), vaso-vagal episodes (VVE) and anxiety-depression (AD) was the object of this population-based study in north-eastern France. A self-administered questionnaire was returned by 2987 adults (age span 18-86 years, 1471 women). The 1-year prevalence for V was 48.3%, for U 39.1% and for D 35.6%. The VDU symptoms were correlated with each other, occurred mostly (69.4%) in various combinations rather than in isolation, less than once per month, and 90% of episodes lasted < or = 2 minutes and occurred < 1/month. The three symptoms were similar in terms of female predominance, temporary profile of the episodes and their link to falls and nausea. Symptom associations including I and symptom episodes of >1 hour increased the risk of falls. The number of drugs taken increased VDU even when controlling for age. Each VDU symptom was correlated with each co-morbidity. The risk factors were for agoraphobia: AD>female gender>VDU; for MSS: female gender>AD>migraine. Logistic regressions controlling for each vestibular symptom showed that V correlated with each co-morbidity, suggesting that V is a symptom as unspecific as the other two and that the three symptoms represent a spectrum resulting from a range of mechanisms or disorders

La psychose est un syndrome apparaissant progressivement à l’adolescence chez des individus à risque selon un processus dynamique appelé transition psychotique. Ces individus à risque sont repérables cliniquement mais les données biologiques actuelles sont insuffisantes pour expliquer l’apparition de la psychose. Au cours de cette thèse, nous avons cherché à identifier les facteurs biologiques responsables de ce processus. Les hypothèses permettant d’expliquer la transition psychotique privilégient l’interaction gène x environnement, sous-tendue par des mécanismes épigénétiques. Nous avons mené une étude des modifications de la méthylation de l’ADN et de la transcription à l’aide de techniques de biologie moléculaire et de bio-informatique à l’échelle pan-génomique. La transition psychotique semble être liée à des modifications de méthylation et de transcription de gènes impliqués dans des mécanismes comme le guidage axonal ou la régulation du stress oxydatif. Ces modifications longitudinales pourraient refléter l’influence de l’environnement. Les facteurs environnementaux pourraient déréguler l’axe biologique du stress dès les phases précoces de la maladie, comme le suggère l’augmentation de la sécrétion de cortisol basal que nous avons montré chez les individus à risque. En outre, il est probable que des spécificités au niveau des gènes et des processus régulant l’épigénome soient également impliquées dans cette réponse individuelle à l’environnement. Nous avons montré l’importance du métabolisme mono-carboné au moins dans un sous-groupe spécifique de patients. Ces résultats doivent être répliqués et étendus dans d’autres paradigmes pour valider l’implication de ces processus dans la transition psychotique. En cas de confirmation, ces voies biologiques pourraient s’avérer être des pistes intéressantes pour développer des thérapeutiques ciblées et relever le défi de la prévention de la psychose chez des individus à risque. / Psychosis is a progressive mental disorder which normally occurs during adolescence in at-risk subjects following a dynamic process termed “psychotic transition”. These at-risk subjects are clinically identifiable but biological data are still insufficient in explaining the onset of psychosis. Throughout this thesis, we aim to identify biological factors implicated in this pathophysiological process. Current hypotheses explaining the psychotic transition favor the interaction between genes and the environment mediated by epigenetic mechanisms. We conducted studies examining methylomic and transcriptomic changes during psychotic transition using molecular biology and bioinformatics techniques at a whole genome scale. Our results suggest that psychotic transition may be linked to methylomic and transcriptomic changes in genes implicated in axon guidance or oxidative stress. These longitudinal changes could be related to environmental factors. Some of these factors could deregulate the hormonal stress response at the earliest phases of psychosis. Indeed, our results show that secretion of basal cortisol is increased in prodromal individuals. Moreover, it is likely that genes and processes regulating epigenetic modifications are also implicated in the individual response to the environment. We have shown the importance of the one-carbon metabolism for at least one sub-group of patients affected by psychosis. Our results should be replicated using other paradigms in order to definitively validate the implication of these various actors in the psychotic transition. If confirmed, knowledge of these biological mechanisms could lead to the development of targeted therapeutics to prevent psychosis in at-risk individuals.

Made available in DSpace on 2016-03-22T17:26:20Z (GMT). No. of bitstreams: 1 Karen Jansen 2.pdf: 601451 bytes, checksum: e84f12927abaa8f47025474e4930cc3b (MD5) Previous issue date: 2009-10-30 / Objective: To evaluate the prevalence of mania and hypomania episode, as well as associated factors, comorbidities, and quality of life among young from 18 to 24 years old the city of Pelotas, RS. Method: This cross-sectional population-based, which was included to a larger study that evaluated Health Behaviors among young from 18 to 24 years old in the city of Pelotas . The sample selection was through conglomerates, and mania e hypomania episode were assessed using a standardized diagnostic interview short, Mini International Neuropsychiatric Interview (MINI), consistent with the DSM-IV and ICD-10. Results: The sample was 1560 young adults. In this, the prevalence of mania or hypomania episode the lifetime were 7,5% and 5,3%, respectively. The young with mania episode showed more prevalence to anxiety, suicide risk and substance abuse. In addition to minor index to quality of life in all domain of SF- 36 (p<0,001). Conclusion: The high prevalence of mania/hypomania episode in young population, associated to co-morbities disorders indicates that THB can being subdiagnostics. While the decline in the quality of life explain the injury in the person life with such pathology / Objetivo: Avaliar a prevalência de episódio de mania e hipomania, bem como, fatores associados, comorbidades e o impacto na qualidade de vida entre jovens de 18 a 24 anos da cidade de Pelotas, RS. Método: Trata-se de um estudo transversal de base-populacional, no qual a seleção amostral foi realizada por conglomerados e os episódios de mania e hipomania foram avaliados através de uma entrevista diagnóstica padronizada breve, Mini Internacional Neuropsychiatric Interview (MINI), compatível com os critérios do DSM-IV e CID-10. Além disso, foi aplicado um questionário com dados sócio-demográficos, e os instrumentos ASSIST e SF-36. Resultados: A amostra foi composta por 1560 jovens. Destes, a prevalência de episódios de mania ou hipomania ao longo da vida foi de 7,5% e 5,3%, respectivamente. Os jovens com episódio de mania apresentaram maior prevalência de transtornos de ansiedade, risco de suicídio e abuso de substâncias, além de menores níveis de qualidade de vida em todos os domínios do SF-36 (p<0,001). Conclusão: A alta prevalência de episódios de mania/hipomania na população de jovens, associada aos transtornos co-mórbidos indica que os THB podem estar sendo subdiagnosticados. Enquanto, o declínio na qualidade de vida demonstra o prejuízo na vida do individuo com tal patologia

Temporal data mining is concerned with the exploration of large sequential (or temporally ordered) data sets to discover some nontrivial information that was previously unknown to the data owner. Sequential data sets come up naturally in a wide range of application domains, ranging from bioinformatics to manufacturing processes. Pattern discovery refers to a broad class of data mining techniques in which the objective is to unearth hidden patterns or unexpected trends in the data. In general, pattern discovery is about finding all patterns of 'interest' in the data and one popular measure of interestingness for a pattern is its frequency in the data. The problem of frequent pattern discovery is to find all patterns in the data whose frequency exceeds some user-defined threshold. Discovery of temporal patterns that occur frequently in sequential data has received a lot of attention in recent times. Different approaches consider different classes of temporal patterns and propose different algorithms for their efficient discovery from the data. This thesis is concerned with a specific class of temporal patterns called episodes and their discovery in large sequential data sets. In the framework of frequent episode discovery, data (referred to as an event sequence or an event stream) is available as a single long sequence of events. The ith event in the sequence is an ordered pair, (Et,tt), where Et takes values from a finite alphabet (of event types), and U is the time of occurrence of the event. The events in the sequence are ordered according to these times of occurrence. An episode (which is the temporal pattern considered in this framework) is a (typically) short partially ordered sequence of event types. Formally, an episode is a triple, (V,<,9), where V is a collection of nodes, < is a partial order on V and 9 is a map that assigns an event type to each node of the episode. When < is total, the episode is referred to as a serial episode, and when < is trivial (or empty), the episode is referred to as a parallel episode. An episode is said to occur in an event sequence if there are events in the sequence, with event types same as those constituting the episode, and with times of occurrence respecting the partial order in the episode. The frequency of an episode is some measure of how often it occurs in the event sequence. Given a frequency definition for episodes, the task is to discover all episodes whose frequencies exceed some threshold. This is done using a level-wise procedure. In each level, a candidate generation step is used to combine frequent episodes from the previous level to build candidates of the next larger size, and then a frequency counting step makes one pass over the event stream to determine frequencies of all the candidates and thus identify the frequent episodes. Frequency counting is the main computationally intensive step in frequent episode discovery. Choice of frequency definition for episodes has a direct bearing on the efficiency of the counting procedure. In the original framework of frequent episode discovery, episode frequency is defined as the number of fixed-width sliding windows over the data in which the episode occurs at least once. Under this frequency definition, frequency counting of a set of |C| candidate serial episodes of size N has space complexity O(N|C|) and time complexity O(ΔTN|C|) (where ΔT is the difference between the times of occurrence of the last and the first event in the data stream). The other main frequency definition available in the literature, defines episode frequency as the number of minimal occurrences of the episode (where, a minimal occurrence is a window on the time axis containing an occurrence of the episode, such that, no proper sub-window of it contains another occurrence of the episode). The algorithm for obtaining frequencies for a set of |C| episodes needs O(n|C|) time (where n denotes the number of events in the data stream). While this is time-wise better than the the windows-based algorithm, the space needed to locate minimal occurrences of an episode can be very high (and is in fact of the order of length, n, of the event stream). This thesis proposes a new definition for episode frequency, based on the notion of, what is called, non-overlapped occurrences of episodes in the event stream. Two occurrences are said to be non-overlapped if no event corresponding to one occurrence appears in between events corresponding to the other. Frequency of an episode is defined as the maximum possible number of non-overlapped occurrences of the episode in the data. The thesis also presents algorithms for efficient frequent episode discovery under this frequency definition. The space and time complexities for frequency counting of serial episodes are O(|C|) and O(n|C|) respectively (where n denotes the total number of events in the given event sequence and |C| denotes the num-ber of candidate episodes). These are arguably the best possible space and time complexities for the frequency counting step that can be achieved. Also, the fact that the time needed by the non-overlapped occurrences-based algorithm is linear in the number of events, n, in the event sequence (rather than the difference, ΔT, between occurrence times of the first and last events in the data stream, as is the case with the windows-based algorithm), can result in considerable time advantage when the number of time ticks far exceeds the number of events in the event stream. The thesis also presents efficient algorithms for frequent episode discovery under expiry time constraints (according to which, an occurrence of an episode can be counted for its frequency only if the total time span of the occurrence is less than a user-defined threshold). It is shown through simulation experiments that, in terms of actual run-times, frequent episode discovery under the non-overlapped occurrences-based frequency (using the algorithms developed here) is much faster than existing methods. There is also a second frequency measure that is proposed in this thesis, which is based on, what is termed as, non-interleaved occurrences of episodes in the data. This definition counts certain kinds of overlapping occurrences of the episode. The time needed is linear in the number of events, n, in the data sequence, the size, N, of episodes and the number of candidates, |C|. Simulation experiments show that run-time performance under this frequency definition is slightly inferior compared to the non-overlapped occurrences-based frequency, but is still better than the run-times under the windows-based frequency. This thesis also establishes the following interesting property that connects the non-overlapped, the non-interleaved and the minimal occurrences-based frequencies of an episode in the data: the number of minimal occurrences of an episode is bounded below by the maximum number of non-overlapped occurrences of the episode, and is bounded above by the maximum number of non-interleaved occurrences of the episode in the data. Hence, non-interleaved occurrences-based frequency is an efficient alternative to that based on minimal occurrences. In addition to being superior in terms of both time and space complexities compared to all other existing algorithms for frequent episode discovery, the non-overlapped occurrences-based frequency has another very important property. It facilitates a formal connection between discovering frequent serial episodes in data streams and learning or estimating a model for the data generation process in terms of certain kinds of Hidden Markov Models (HMMs). In order to establish this connection, a special class of HMMs, called Episode Generating HMMs (EGHs) are defined. The symbol set for the HMM is chosen to be the alphabet of event types, so that, the output of EGHs can be regarded as event streams in the frequent episode discovery framework. Given a serial episode, α, that occurs in the event stream, a method is proposed to uniquely associate it with an EGH, Λα. Consider two N-node serial episodes, α and β, whose (non-overlapped occurrences-based) frequencies in the given event stream, o, are fα and fβ respectively. Let Λα and Λβ be the EGHs associated with α and β. The main result connecting episodes and EGHs states that, the joint probability of o and the most likely state sequence for Λα is more than the corresponding probability for Λβ, if and only if, fα is greater than fβ. This theoretical connection has some interesting consequences. First of all, since the most frequent serial episode is associated with the EGH having the highest data likelihood, frequent episode discovery can now be interpreted as a generative model learning exercise. More importantly, it is now possible to derive a formal test of significance for serial episodes in the data, that prescribes, for a given size of the test, a minimum frequency for the episode needed in order to declare it as statistically significant. Note that this significance test for serial episodes does not require any separate model estimation (or training). The only quantity required to assess significance of an episode is its non-overlapped occurrences-based frequency (and this is obtained through the usual counting procedure). The significance test also helps to automatically fix the frequency threshold for the frequent episode discovery process, so that it can lead to what may be termed parameterless data mining. In the framework considered so far, the input to frequent episode discovery process is a sequence of instantaneous events. However, in many applications events tend to persist for different periods of time and the durations may carry important information from a data mining perspective. This thesis extends the framework of frequent episodes to incorporate such duration information directly into the definition of episodes, so that, the patterns discovered will now carry this duration information as well. Each event in this generalized framework looks like a triple, (Ei, ti, τi), where Ei, as earlier, is the event type (from some finite alphabet) corresponding to the ith event, and ti and τi denote the start and end times of this event. The new temporal pattern, called the generalized episode, is a quadruple, (V, <, g, d), where V, < and g, as earlier, respectively denote a collection of nodes, a partial order over this collection and a map assigning event types to nodes. The new feature in the generalized episode is d, which is a map from V to 2I, where, I denotes a collection of time interval possibilities for event durations, which is defined by the user. An occurrence of a generalized episode in the event sequence consists of events with both 'correct' event types and 'correct' time durations, appearing in the event sequence in 'correct' time order. All frequency definitions for episodes over instantaneous event streams are applicable for generalized episodes as well. The algorithms for frequent episode discovery also easily extend to the case of generalized episodes. The extra design choice that the user has in this generalized framework, is the set, I, of time interval possibilities. This can be used to orient and focus the frequent episode discovery process to come up with temporal correlations involving only time durations that are of interest. Through extensive simulations the utility and effectiveness of the generalized framework are demonstrated. The new algorithms for frequent episode discovery presented in this thesis are used to develop an application for temporal data mining of some data from car engine manufacturing plants. Engine manufacturing is a heavily automated and complex distributed controlled process with large amounts of faults data logged each day. The goal of temporal data mining here is to unearth some strong time-ordered correlations in the data which can facilitate quick diagnosis of root causes for persistent problems and predict major breakdowns well in advance. This thesis presents an application of the algorithms developed here for such analysis of the faults data. The data consists of time-stamped faults logged in car engine manufacturing plants of General Motors. Each fault is logged using an extensive list of codes (which constitutes the alphabet of event types for frequent episode discovery). Frequent episodes in fault logs represent temporal correlations among faults and these can be used for fault diagnosis in the plant. This thesis describes how the outputs from the frequent episode discovery framework, can be used to help plant engineers interpret the large volumes of faults logged, in an efficient and convenient manner. Such a system, based on the algorithms developed in this thesis, is currently being used in one of the engine manufacturing plants of General Motors. Some examples of the results obtained that were regarded as useful by the plant engineers are also presented.

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