103 research outputs found
VĂ©rification du logiciel CFX pour la simulation de l'interaction arc-Ă©coulement dans les disjoncteurs haute-tension.
RĂSUMĂ
Le but du projet est de vĂ©rifier sâil est envisageable dâutiliser le code commercial CFX de ANSYS
Inc. dans le but de simuler la coupure du courant dans un disjoncteur Ă haute tension. CFX est un
code de dynamique des fluides au sens large, avec des options disponibles pour simuler différents
types de problĂšmes dâĂ©coulements de fluides, en trois dimensions spatiales. La mĂ©thodologie utilisĂ©e
est principalement une comparaison entre deux codes, et avec la solution analytique, lorsque la
géométrie utilisée le permet. Le code utilisé comme base de comparaison est MC3, qui est un code
ayant dĂ©jĂ Ă©tĂ© validĂ©, conçu spĂ©cialement pour simuler lâallumage et la coupure dâun arc Ă©lectrique
dans une gĂ©omĂ©trie de disjoncteur haute tension, avec une approximation dâaxisymĂ©trie de la gĂ©omĂ©trie.
LâidĂ©e derriĂšre le projet est donc de passer dâune mĂ©thode de calcul en deux dimensions
que lâon sait fonctionnelle, avec des approximations pour obtenir des conditions axisymĂ©triques, Ă
une méthode de calcul pleinement tridimensionnelle en terme spatial, diminuant ainsi le nombre
dâapproximations Ă effectuer.
Les concepts de vérification et de validation de codes sont expliqués, avec un résumé de certaines
méthodes particuliÚres. Une brÚve description du fonctionnement des disjoncteurs haute tension
est donnée, avec un résumé des principes physiques utilisés. Les équations physiques résolues par
les solveurs sont données (dynamique des gaz, rayonnement, électromagnétisme), avec un résumé
qualitatif des modÚles numériques utilisés.
La géométrie et la physique des cas tests utilisés sont décrits, avec la solution analytique lorsque
cela est possible. Les résultats de ces cas tests sont analysés et comparés entre les deux codes
et la solution analytique. Ces cas tests ont pour but de simuler des cas simples faisant ressortir
séparément chacune des caractéristiques physiques présentes dans un disjoncteur haute tension.
Les caractĂ©ristiques physiques dâimportance sont donc vĂ©rifiĂ©es une Ă la fois. Une tentative de
calcul sur une situation un peu plus réaliste a finalement été effectuée.----------ABSTRACT
The goal of the project is to verify the possibility of using ANSYS Inc.âs CFX commercial code for
simulations of current interruption in a high-voltage circuit breaker. CFX is a fluid dynamic code
in a wide sense, with available options for simulating many fluid flow problems, in three spatial
dimensions. The method used for the verification is mainly a code to code comparison, and with
analytical solutions, when the geometry allow it. The code used as comparison basis is MC3, which
has already been validated. It is specially made for simulating ignition and cutting of electric arcs
in a circuit breaker geometry, with an axisymmetric approximation. The idea of the project is to
pass from a well validated two dimensional method, with axisymmetric approximations, to a fully
three spatial dimensions method, decreasing the number of approximations to do.
The code verification and validation concepts are explained, with a summary of some particular
methods. A brief description of high-voltage circuit breakers operation is given, with a summary of
physical principles used for its modeling. The physical equations solved by the computer codes are
given (gas dynamic, radiation, electromagnetism), with a qualitative summary of numerical models
used.
The geometry and physics of test cases used are described, with analytical solution when possible.
The results of theses test cases are analyzed and compared between the two codes and the analytical
solution. The goal of theses test cases is to simulate simple cases showing separately each physical
characteristics present in a high-voltage circuit breaker. The physical characteristics of importance
are then verified one by one. An attempt on a more realistic and complex situation was finally done
DĂ©coder les Ă©motions Ă travers la musique et la voix
Lâobjectif de cette theÌse est de comparer les meÌcanismes fondamentaux lieÌs aÌ la perception eÌmotionnelle vocale et musicale. Cet objectif est sustenteÌ par de nombreux rapports et theÌories appuyant l'ideÌe de substrats neuronaux communs pour le traitement des eÌmotions vocales et musicales. Il est proposeÌ que la musique, afin de nous faire percevoir des eÌmotions, recrute/recycle les circuits eÌmotionnels qui ont eÌvolueÌ principalement pour le traitement des vocalisations biologiquement importantes (p.ex. cris pleurs). Bien que certaines eÌtudes ont releveÌ de grandes similariteÌs entre ces deux timbres (voix, musique) du point de vue ceÌreÌbral (traitement eÌmotionnel) et acoustique (expressions eÌmotionnelles), certaines diffeÌrences acoustiques et neuronales speÌcifique aÌ chaque timbre ont eÌgalement eÌteÌ observeÌes. Il est possible que les diffeÌrences rapporteÌes ne soient pas speÌcifiques au timbre, mais observeÌes en raison de facteurs speÌcifiques aux stimuli utiliseÌs tels que leur complexiteÌ et leur longueur. Ici, il est proposeÌ de contourner les probleÌmes de comparabiliteÌ de stimulus, par lâutilisation des expressions eÌmotionnelles les plus simples dans les deux domaines.
Pour atteindre lâobjectif global de la theÌse, les travaux ont eÌteÌ reÌaliseÌs en deux temps. PremieÌrement, une batterie de stimuli eÌmotionnels musicaux comparables aux stimuli vocaux deÌjaÌ disponibles (Voix Affectives MontreÌalaises) a eÌteÌ deÌveloppeÌe. Des stimuli (EÌclats EÌmotionnels Musicaux) exprimant 4 eÌmotions (joie, peur, tristesse, neutraliteÌ) performeÌs au violon et aÌ la clarinette ont eÌteÌ enregistreÌs et valideÌs. Ces EÌclats EÌmotionnels Musicaux ont obtenu un haut taux de reconnaissance (M=80.4%) et reçu des jugements dâarousal (eÌveil/stimulation) et de valence correspondant aÌ lâeÌmotion quâil repreÌsentait. Nous avons donc pu, dans un deuxieÌme temps, utiliser ces stimuli nouvellement valideÌs et les Voix Affectives MontreÌalaises pour reÌaliser deux eÌtudes de comparaison expeÌrimentales. Dâabord, nous avons effectueÌ aÌ lâaide de lâimagerie par reÌsonnance magneÌtique fonctionnelle une comparaison des circuits neuronaux utiliseÌs pour le traitement de ces deux types dâexpressions eÌmotionnelles. IndeÌpendamment de leur nature vocale ou musicale, une activiteÌ ceÌreÌbrale speÌcifique aÌ l'eÌmotion a eÌteÌ observeÌe dans le cortex auditif (centreÌe sur le gyrus temporal supeÌrieur) et dans les reÌgions limbiques (gyrus parahippocampique/amygdale), alors qu'aucune activiteÌ speÌcifique aux stimuli vocaux ou musicaux n'a eÌteÌ observeÌe. Par la suite, nous avons compareÌ la perception des eÌmotions vocales et musicales sous simulation dâimplant cochleÌaire. Cette simulation affectant grandement la perception des indices acoustiques lieÌs aux hauteurs tonales (important pour la discrimination eÌmotionnelle), nous a permis de deÌterminer quels indices acoustiques secondaires aÌ ceux-ci sont importants pour la perception eÌmotionnelle chez les utilisateurs dâimplant cochleÌaire. Lâexamen des caracteÌristiques acoustiques et des jugements eÌmotionnels a permis de deÌterminer que certaines caracteÌristiques timbrales (clarteÌ, eÌnergie et rugositeÌ) communes aÌ la voix et la musique sont utiliseÌes pour reÌaliser des jugements eÌmotionnels sous simulations dâimplant cochleÌaire, dans les deux domaines.
Lâattention que nous avons porteÌe au choix des stimuli nous a permis de mettre de lâavant les grandes similariteÌs (acoustique, neuronales) impliqueÌes dans la perception des eÌmotions vocales et musicales. Cette convergence dâeÌvidence donne un appui important aÌ lâhypotheÌse de circuits neuronaux fondamentaux commun pour le traitement des eÌmotions vocales et musicales.The aim of this thesis is to compare the fundamental mechanisms related to vocal and musical emotion perception. This objective is supported by many reports and theories bringing forward the idea of common neural substrates for the treatment of vocal and musical emotions. It is proposed that music, in order to make us perceive emotions, recruits/recycles the emotional circuits that evolved mainly for the treatment of biologically important vocalisations (e.g. cries, screams). Although some studies have found great similarities between these two timbres (voice, music) from the cerebral (emotional treatment) and acoustic (emotional expressions) point of view, some acoustic and neural differences specific to each timbre have also been reported. It is possible that the differences described are not specific to the timbre but are observed due to factors specific to the stimuli used such as their complexity and length. Here, it is proposed to circumvent the problems of stimulus comparability by using the simplest emotional expressions in both domains.
To achieve the overall objective of the thesis, the work was carried out in two stages. First, a battery of musical emotional stimuli comparable to the vocal stimuli already available (Montreal Affective Voices) was developed. Stimuli (Musical Emotional Bursts) expressing 4 emotions (happiness, fear, sadness, neutrality) performed on the violin and clarinet were recorded and validated. These Musical Emotional Bursts obtained a high recognition rate (M = 80.4%) and received arousal and valence judgments corresponding to the emotion they represented. Secondly, we were able to use these newly validated stimuli and the Montreal Affective Voices to perform two experimental comparison studies. First, functional magnetic resonance imaging was used to compare the neural circuits used to process these two types of emotional expressions. Independently of their vocal or musical nature, emotion-specific activity was observed in the auditory cortex (centered on the superior temporal gyrus) and in the limbic regions (amygdala/parahippocampal gyrus), whereas no activity specific to vocal or musical stimuli was observed. Subsequently, we compared the perception of vocal and musical emotions under cochlear implant simulation. This simulation greatly affects the perception of acoustic indices related to pitch (important for emotional discrimination), allowing us to determine which acoustic indices secondary to these are important for emotional perception in cochlear implant users. Examination of acoustic characteristics and emotional judgments determined that certain timbral characteristics (brightness, energy, and roughness) common to voice and music are used to make emotional judgments in both domains, under cochlear implant simulations.
The specific attention to our stimuli selection has allowed us to put forward the similarities (acoustic, neuronal) involved in the perception of vocal and musical emotions. This convergence of evidence provides important support to the hypothesis of a fundamental common neural circuit for the processing of vocal and musical emotions
Utilisation normale du mode et du tempo par les amusiques adultes, lors de jugements Ă©motionnels
Notre aptitude Ă dĂ©terminer si un extrait de musique est gai ou triste rĂ©side dans notre capacitĂ© Ă extraire les caractĂ©ristiques Ă©motionnelles de la musique. Une de ces caractĂ©ristiques, le mode, est liĂ©e aux hauteurs musicales et une autre, le tempo, est temporelle (Hevner, 1937; 1935). Une perception dĂ©ficitaire de lâune de ces caractĂ©ristiques (ex. les hauteurs) devrait affecter lâexpĂ©rience Ă©motionnelle. Lâamusie congĂ©nitale est caractĂ©risĂ©e par un traitement anormal des hauteurs (Peretz, 2008). Toutefois, peu de donnĂ©es ont Ă©tĂ© accumulĂ©es sur les rĂ©ponses Ă©motionnelles des amusiques face Ă la perception du mode. La perception Ă©motionnelle liĂ©e Ă celui-ci pourrait ĂȘtre prĂ©servĂ©e, chez les amusiques en raison de leur perception implicite des hauteurs (Peretz, et coll., 2009). Dans un premier temps, cette Ă©tude cherchera Ă dĂ©terminer dans quelle mesure les amusiques adultes utilisent le mode relativement au tempo dans la distinction dâune piĂšce gaie, dâune triste. Dans cette optique, onze amusiques et leurs contrĂŽles appariĂ©s ont jugĂ© des extraits de musique classique gais et tristes, dans leur forme originale et dans deux versions modifiĂ©es : (1) mode inversĂ© (transcrit dans le mode opposĂ© mineur â majeur) et (2) tempo neutralisĂ© (rĂ©glĂ© Ă une valeur mĂ©diane), oĂč le mode Ă©merge comme caractĂ©ristique dominante. Les participants devaient juger si les extraits Ă©taient gais ou tristes sur une Ă©chelle de 10-points, pendant que leurs rĂ©ponses Ă©lectromyographiques (zygomatique et corrugateur) Ă©taient enregistrĂ©es. Les participants ont par la suite Ă©tĂ© rĂ©invitĂ©s au laboratoire pour rĂ©aliser une tĂąche non Ă©motionnelle de discrimination des modes (majeur, mineur), dans laquelle des paires de stimuli composĂ©s de versions plus courtes des extraits originaux et leur version au mode inversĂ© leur Ă©taient prĂ©sentĂ©es. Les participants (14; 7 amusiques) devaient juger si les paires Ă©taient identiques (mĂȘme stimulus, mĂȘme mode) ou diffĂ©rentes (mĂȘme stimulus, modes diffĂ©rents). Dans cette derniĂšre tĂąche, les amusiques ont eu plus de difficultĂ© que leurs contrĂŽles Ă discriminer les modes, mais les amusiques comme leurs contrĂŽles se sont montrĂ©s sensibles aux manipulations du mode et du tempo, dans la tĂąche Ă©motionnelle. Ces rĂ©sultats supportĂ©s par des rĂ©ponses EMG normales prĂ©supposent des habiletĂ©s prĂ©servĂ©es ou implicites de traitement tonal dans lâamusie congĂ©nitale.Our ability to determine if a music piece is happy or sad depends on our capacity to extracts the main emotional characteristics of music. One of these characteristics, the mode, is a pitch based constituent, and another one, the tempo, is a temporal factor (Hevner, 1937; 1935). The inability to extract one of those characteristics (pitch) should affect the emotional experience. Congenital amusia is characterized by anomalous pitch processing (Peretz, 2008). Yet, little is known about the amusicsâ emotional responses to mode. Perhaps emotional perception of this characteristic is preserved due to the amusicsâ implicit pitch processing (Peretz, et coll., 2009). First, we decided to examine how amusic adults use mode relative to tempo in distinguishing happy from sad musical excerpts. To this aim, we tested whether eleven amusics and their matched controls judged excerpts of happy and sad classical music in their original form and in two manipulated conditions: the ââinverted mode conditionââ where the excerpts were transcribed in the opposite mode (majorâminor); and the ââneutralized tempo conditionââ where all tempi were set to the same median value, hence the mode emerges as the main emotional characteristic. Participants judged on a 10-point scale whether each excerpt was sad or happy while their electromyographical responses (zygomatic, corrugator activity) were recorded. Participants were then invited back to the laboratory, to complete a non-emotional task. This mode discrimination (minor, major) task consisted of pairs of original and inverted mode stimuli, made of shorter versions of the previously used stimuli. Participants (14; 7 amusics) had to judge whether the pairs were identical (same stimuli, same mode) or different (same stimuli different modes). In the latter task, amusics had significantly more difficulty in discriminating the mode compared to their controls. However, amusics did not differ from controls in showing normal sensitivity to mode and tempo manipulations in the emotional task. These normal behavioural judgments supported by normal psychophysiological measures indicate that emotional responses may reveal preserved or implicit pitch processing abilities in congenital amusia
La génétique au service de la conservation d'une espÚce menacée endémique à Madagascar : la tortue radiée Astrochelys radiata
ThÚse numérisée par la Division de la gestion de documents et des archives de l'Université de Montréal
Mapping Abstract Visual Feedback to a Dimensional Model of Emotion
Recent HCI research has looked at conveying emotions through non-visual modalities, such as vibrotactile and thermal feedback. However, emotion is primarily conveyed through visual signals, and so this research aims to support the design of emotional visual feedback. We adapt and extend the design of the "pulsing amoeba" [29], and measure the emotion conveyed through the abstract visual designs. It is a first step towards more holistic multimodal affective feedback combining visual, auditory and tactile stimuli. An online survey garnered valence and arousal ratings of 32 stimuli that varied in colour, contour, pulse size and pulse speed. The results support previous research but also provide new findings and highlight the effects of each individual visual parameter on perceived emotion. We present a mapping of all stimulus combinations onto the common two-dimensional valence-arousal model of emotion
Compromised cerebrovascular regulation and cerebral oxygenation in pulmonary arterial hypertension
Background : Functional cerebrovascular regulatory mechanisms are important for maintaining constant cerebral blood flow and oxygen supply in heathy individuals and are altered in heart failure. We aim to examine whether pulmonary arterial hypertension (PAH) is associated with abnormal cerebrovascular regulation and lower cerebral oxygenation and their physiological and clinical consequences.
Methods and Results : Resting mean flow velocity in the middle cerebral artery mean flow velocity in the middle cerebral artery (MCAvmean); transcranial Doppler), cerebral pressureâflow relationship (assessed at rest and during squatâstand maneuvers; analyzed using transfer function analysis), cerebrovascular reactivity to CO2, and central chemoreflex were assessed in 11 patients with PAH and 11 matched healthy controls. Both groups also completed an incremental ramp exercise protocol until exhaustion, during which MCAvmean, mean arterial pressure, cardiac output (photoplethysmography), endâtidal partial pressure of CO2, and cerebral oxygenation (nearâinfrared spectroscopy) were measured. Patients were characterized by a significant decrease in resting MCAvmean (P<0.01) and higher transfer function gain at rest and during squatâstand maneuvers (both P<0.05). Cerebrovascular reactivity to CO2 was reduced (P=0.03), whereas central chemoreceptor sensitivity was increased in PAH (P<0.01), the latter correlating with increased resting ventilation (R2=0.47; P<0.05) and the exercise ventilation/CO2 production slope (Embedded Image slope; R2=0.62; P<0.05) during exercise for patients. Exerciseâinduced increases in MCAvmean were limited in PAH (P<0.05). Reduced MCAvmean contributed to impaired cerebral oxygen delivery and oxygenation (both P<0.05), the latter correlating with exercise capacity in patients with PAH (R2=0.52; P=0.01).
Conclusions : These findings provide comprehensive evidence for physiologically and clinically relevant impairments in cerebral hemodynamic regulation and oxygenation in PAH
Developmental Perceptual Impairments: Cases When Tone-Deafness and Prosopagnosia Co-occur
Studies have shown subtle gray and white matter abnormalities in subjects with several developmental disorders including prosopagnosia, tone-deafness, and dyslexia. Correlational evidence suggests that tone-deafness and dyslexia tend to co-occur, suggesting a link between these two developmental disorders. However, it is not known whether tone-deafness can also be associated with other developmental disorders such as impaired face recognition or prosopagnosia. We addressed this question by assessing face perception abilities in a group of tone-deaf individuals and matched non-tone-deaf subjects. The Cambridge (CFMT) and the Warrington (WRMT) face memory tests were used to assess face processing in the combined group of 12, out of which six tested in the tone-deaf range. Only tone-deaf participants (two out of six) scored in the impaired range on the CFMT, one of whom was also impaired on the WRMT face memory test. Furthermore, the melodic composite score of all participants on the Montreal Battery of Evaluation of Amusia significantly correlated with their face recognition score on the CFMT. Our results suggest that in some cases tone-deafness might co-occur with face recognition impairments. It is implausible that both deficits are linked to a single cognitive dysfunction that spans different perceptual systems in different modalities. They are likely associated with a common pathogenetic mechanism of early development that leads to anomalies affecting the function of different brain systems or the connection between regions
Personalized Risk Assessment for Prevention and Early Detection of Breast Cancer: Integration and Implementation (PERSPECTIVE I&I).
Early detection of breast cancer through screening reduces breast cancer mortality. The benefits of screening must also be considered within the context of potential harms (e.g., false positives, overdiagnosis). Furthermore, while breast cancer risk is highly variable within the population, most screening programs use age to determine eligibility. A risk-based approach is expected to improve the benefit-harm ratio of breast cancer screening programs. The PERSPECTIVE I&I (Personalized Risk Assessment for Prevention and Early Detection of Breast Cancer: Integration and Implementation) project seeks to improve personalized risk assessment to allow for a cost-effective, population-based approach to risk-based screening and determine best practices for implementation in Canada. This commentary describes the four inter-related activities that comprise the PERSPECTIVE I&I project. 1: Identification and validation of novel moderate to high-risk susceptibility genes. 2: Improvement, validation, and adaptation of a risk prediction web-tool for the Canadian context. 3: Development and piloting of a socio-ethical framework to support implementation of risk-based breast cancer screening. 4: Economic analysis to optimize the implementation of risk-based screening. Risk-based screening and prevention is expected to benefit all women, empowering them to work with their healthcare provider to make informed decisions about screening and prevention
A value-based comparison of the management of ambulatory respiratory diseases in walk-in clinics, primary care practices, and emergency departments : protocol for a multicenter prospective cohort study
Background:
In Canada, 30%-60% of patients presenting to emergency departments are ambulatory. This category has been labeled as a source of emergency department overuse. Acting on the presumption that primary care practices and walk-in clinics offer equivalent care at a lower cost, governments have invested massively in improving access to these alternative settings in the hope that patients would present there instead when possible, thereby reducing the load on emergency departments. Data in support of this approach remain scarce and equivocal.
Objective:
The aim of this study is to compare the value of care received in emergency departments, walk-in clinics, and primary care practices by ambulatory patients with upper respiratory tract infection, sinusitis, otitis media, tonsillitis, pharyngitis, bronchitis, influenza-like illness, pneumonia, acute asthma, or acute exacerbation of chronic obstructive pulmonary disease.
Methods:
A multicenter prospective cohort study will be performed in Ontario and Québec. In phase 1, a time-driven activity-based costing method will be applied at each of the 15 study sites. This method uses time as a cost driver to allocate direct costs (eg, medication), consumable expenditures (eg, needles), overhead costs (eg, building maintenance), and physician charges to patient care. Thus, the cost of a care episode will be proportional to the time spent receiving the care. At the end of this phase, a list of care process costs will be generated and used to calculate the cost of each consultation during phase 2, in which a prospective cohort of patients will be monitored to compare the care received in each setting. Patients aged 18 years and older, ambulatory throughout the care episode, and discharged to home with one of the aforementioned targeted diagnoses will be considered. The estimated sample size is 1485 patients. The 3 types of care settings will be compared on the basis of primary outcomes in terms of the proportion of return visits to any site 3 and 7 days after the initial visit and the mean cost of care. The secondary outcomes measured will include scores on patient-reported outcome and experience measures and mean costs borne wholly by patients. We will use multilevel generalized linear models to compare the care settings and an overlap weights approach to adjust for confounding factors related to age, sex, gender, ethnicity, comorbidities, registration with a family physician, socioeconomic status, and severity of illness.
Results:
Phase 1 will begin in 2021 and phase 2, in 2023. The results will be available in 2025.
Conclusions:
The end point of our program will be for deciders, patients, and care providers to be able to determine the most appropriate care setting for the management of ambulatory emergency respiratory conditions, based on the quality and cost of care associated with each alternative
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