In any health-care system, early identification of individuals who are most at risk of developing an illness is vital, not only to ensure that a patient is provided with the appropriate treatment, but also to avoid the considerable costs associated with unnecessary hospitalization. To achieve this goal there is a need for a breakthrough prediction method that is capable of dealing with a real world medical data which is inherently complex. In this study, we show how standard classification algorithms can be employed collectively to predict the length of stay in a hospital of a patient in the upcoming year, based on their medical history. Multiple classifiers are used to perform the prediction task, since real world medical data is significantly complex making the classification task very challenging. The data is voluminous, consists of wide range of class values some of which with a few instances, and it is highly unbalanced making the classification of minority classes very difficult. We propose two Sequential Ensemble Classification (SEC) schemes, one based on an ensemble of homogeneous classifiers, and a second based on a heterogeneous ensemble of classifiers, in three hierarchical granularity levels. The goal of using this system is to provide increased performance over the standard classifiers. This method is highly beneficial when dealing with complex data which is multi-class and highly unbalanced.

Les balances manométriques sont utilisées en métrologie des pressions statiques.Des projets européens tel qu'Euromet 463 ont mis en évidence des écarts systématiques entreles mesures expérimentales et les calculs des paramètres nécessaires à la caractérisation desbalances de référence. La vitesse de chute du piston est l'un d'eux pourtant essentiel dans laprocédure d'étalonnage. L'objectif des travaux de thèse est l'ajustement des méthodesd'estimation de cette vitesse de chute. Cela permettra d'améliorer la caractérisation du jeuinterne de la balance, de déterminer plus précisément la section effective de ce jeu et parconséquent d'améliorer l'incertitude portant sur le coefficient de déformation, paramètre clé del'étalonnage par comparaison. Jusqu'à présent le modèle de calcul de l'écoulement du fluidedans la balance était quasi unidimensionnel. Il assimilait le jeu entre le piston et le cylindre àdeux parois parallèles. Dans cette étude, les équations de l'écoulement du flu ide sont modifiéespour évaluer l'influence du modèle dans un jeu annulaire. Les corrections dues à la vitesse dechute du piston sont également prises en compte. Les calculs des déformations des structuressont réalisés en utilisant la méthode des éléments finis. Les travaux expérimentaux portent surdes ensembles piston-cylindre 50, 200 et 1000 MPa du Laboratoire National de Métrologie etd'Essais (LNE). Une confrontation calcul-expérience est réalisée en prenant en compte lesparamètres de variabilités tels que la géométrie ou les propriétés du fluide.

Att alla oavsett ålder, mer eller mindre har funderingar över världens struktur och beskaffenhet tror jag mig våga påstå. Hur dessa ser ut i de lägre åldrarna är en intressant fråga som jag tittat närmare på. Genom enskilda elevintervjuer och litteraturstudier har jag sökt svar på frågor som; Vilka uppfattningar/kunskaper har 8-åringar om begreppet luft? Hur ser elevernas vardagsförklaringar ut jämfört med de vetenskapliga? Hur kan jag som blivande lärare använda mig av elevernas vardagstänkande? Svaren på mina tre frågor kan kort sammanfattas som följer: Att tankar om begreppet luft fanns. Luft är något självklart, nödvändigt och alltid närvarande. Tankestrukturen hos eleverna är ett vardagstänkande som förklaras på ett vardagligt språk. Uppmärksammandet av begreppet lugt gjorde även att ytterligare tankar om luft kom fram. Medveten om hur barnen tänker och förstår saker och ting får jag som blivande pedagog möjlighet att agera och bygga min undervisning vidare utifrån detta. Detta ger den meningsfulla undervisning jag som pedagog ska sträva efter. Med en ökad insikt om att även små barn har funderingar om naturvetenskapliga begrepp hoppas jag kunna visa att det är mycket lönsamt och givande att jobba på ett förundersökande sätt. Genom att eleverna är delaktiga från början och får hjälpa till att forma undervisningen får jag respons i form av ett positivt engagemang, nyfikenhet och vetgirighet.

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Thèse numérisée par la Division de la gestion de documents et des archives de l'Université de Montréal

Vox Machina, for soprano, chamber ensemble, real-time digital signal processing and digital sounds, deals with the historical relationship between humanity and machines. The text uses excerpts drawn from a variety of sources, all in the public domain, as well as material written especially for the piece by the composer. The instrumental ensemble consists of 8 performers: flute, b-flat clarinet, horn, violin, viola, cello, guitar and percussion. A conductor is required, as well as a technician to control a mixing board and the performance of computer-generated sections of music. Digital sounds may be performed directly from computer, or may be played from DAT cassette.

Ensemble learning is a promising direction of research in machine learning, in which an ensemble classifier gives better predictive and more robust performance for classification problems by combining other learners. Meanwhile agent-based systems provide frameworks to share knowledge from multiple agents in an open context. This thesis combines multi-agent knowledge sharing with ensemble methods to produce a new style of learning system for open environments. We now are surrounded by many smart objects such as wireless sensors, ambient communication devices, mobile medical devices and even information supplied via other humans. When we coordinate smart objects properly, we can produce a form of collective intelligence from their collaboration. Traditional ensemble methods and agent-based systems have complementary advantages and disadvantages in this context. Traditional ensemble methods show better classification performance, while agent-based systems might not guarantee their performance for classification. Traditional ensemble methods work as closed and centralised systems (so they cannot handle classifiers in an open context), while agent-based systems are natural vehicles for classifiers in an open context. We designed an open and social ensemble learning architecture, named J-model, to merge the conflicting benefits of the two research domains. The J-model architecture is based on a service choreography approach for coordinating classifiers. Coordination protocols are defined by interaction models that describe how classifiers will interact with one another in a peer-to-peer manner. The peer ranking algorithm recommends more appropriate classifiers to participate in an interaction model to boost the success rate of results of their interactions. Coordinated participant classifiers who are recommended by the peer ranking algorithm become an ensemble classifier within J-model. We evaluated J-model’s classification performance with 13 UCI machine learning benchmark data sets and a virtual screening problem as a realistic classification problem. J-model showed better performance of accuracy, for 9 benchmark sets out of 13 data sets, than 8 other representative traditional ensemble methods. J-model gave better results of specificity for 7 benchmark sets. In the virtual screening problem, J-model gave better results for 12 out of 16 bioassays than already published results. We defined different interaction models for each specific classification task and the peer ranking algorithm was used across all the interaction models. Our research contributions to knowledge are as follows. First, we showed that service choreography can be an effective ensemble coordination method for classifiers in an open context. Second, we used interaction models that implement task specific coordinations of classifiers to solve a variety of representative classification problems. Third, we designed the peer ranking algorithm which is generally and independently applicable to the task of recommending appropriate member classifiers from a classifier pool based on an open pool of interaction models and classifiers.

Graduate

The aim of this study is to explore criteria characterizing music teacher’s strategies when trying to adapt their teaching to individual students. The interaction of three music teachers with their students was explored in case studies in different parts of Sweden (a pre-study, and the main study consisting of two parallel studies). The research interest especially concerns teaching class ensemble addressing teenagers in the tuition provided under the curriculum of Swedish secondary and upper secondary school.  This study adopts the perspective of cultural psychology according to which learning is understood as being relational, taking place in a cultural context, depending on available cultural resources and affected by it. Cultural tools are considered mediators of meaning and crucial for learning. Of special interest to the present study are the ways in which teachers distribute knowledge to their students. Many-sided data were collected in all case studies: series of lessons were observed and video-documented; preliminary results were followed up in semi-structured interviews with the teachers, respectively. The results show similarities in the use of general strategies; e.g. peer-teaching and -learning in the classroom and flexibility in using and developing cultural tools. Results also show three diverging practices; rehearsal-room practice, supervisor-practice and ensemble-leading-practice. The results are discussed from a societal perspective, in light of Swedish School history. Issues concerning the government of the School and equivalence are addressed.  An unexpected result is that the concept “individually adapted ensemble teaching” may be understood very differently among music teachers actively involved in teachers’ education. The need for development of professional concepts is further underlined by the findings that teachers develop new cultural tools within different practices. This is discussed related to the framing of the central curricula.