La communication quantique vise la génération, la distribution et le stockage de qubits afin d'établir de véritables réseaux quantiques. Le stockage cohérent, efficace et réversible d'états photoniques dans des mémoires atomiques est donc nécessaire et représente actuellement un enjeu majeur de la science de l'information quantique. Ainsi, de nombreux supports de stockage, tels que les ensembles d'atomes froids ou à l'état solide, sont envisagés afin de satisfaire au mieux les propriétés attendues d'une mémoire quantique. Les travaux présentés dans ce manuscrit s'inscrivent dans ce contexte et décrivent la réalisation expérimentale d'une mémoire basée sur le protocole DLCZ dans un ensemble d'atomes froids de 87Rb. Un dispositif de double piège magnéto-optique permet de refroidir et de confiner cet ensemble au sein d'un piège dont le temps de vie est ~15 s, et de le manipuler en vue du stockage quantique. Nous disposons ainsi d'un nuage présentant une épaisseur optique à résonance de l'ordre de 5, et dont les atomes sont refroidis à une dizaine de µK. La mise en place du protocole DLCZ dans cet ensemble atomique consiste à créer des états cohérents de la matière puis à les relire, à partir de diffusions Raman qui s'accompagnent de la génération de photons uniques corrélés en impulsion. Les premiers résultats obtenus montrent des corrélations non-classiques, affichant une violation forte de l'inégalité de Cauchy-Schwarz, pour une efficacité de lecture de l'ordre de 4% et un temps de cohérence de l'état stocké de ~800 ns. Cette mémoire, utilisée comme une source de photons uniques annoncés, fait partie d'un projet pour lequel une interface basée sur de l'optique non-linéaire / Quantum communication aims at generating, distributing and storing qubits between distant locations, in view of implementing actual quantum networks. Coherent, efficient and reversible storage of photonic states in atomic memories is thus necessary and represents a major challenge in quantum information science. Several storage medium, such as cold atomic or solid-state ensembles, are considered so as to satisfy at best the different benchmarks of a quantum memory. In this context, the work presented in this manuscript describes the experimental realization of a memory based on the DLCZ protocol in cold atomic ensemble of 87Rb. A double magneto-optical trap system allows cooling and confining this ensemble within a trap showing a lifetime of 15 s, and to manipulate it for quantum storage. This cloud shows a resonant optical thickness of about 5, and atoms are cooled down to 10 µK. The implementation of the DLCZ protocol in this atomic ensemble consists in creating coherent states of matter and then to read them, using Raman scattering events which come along with the generation of pairs of single photons correlated in momentum. First results show non-classical correlations, which exhibit a strong violation of the Cauchy-Schwarz inequality, with a read-out efficiency of about $4\%$ and a coherence time of the stored state on the order of 800 ns. This memory, used as a heralded single photon source, is part of a project in which an interface based on non-linear guided wave optics has been built and caracterized so as to convert the 795 nm single photons generated by the memory to the telecom wavelength of 1560 nm. Both elements, combined with a entangled photon source withi

Ensembles are today routinely applied to estimate uncertainty in numerical predictions of complex systems such as the weather. Instead of initializing a single numerical forecast, using only the best guess of the present state as initial conditions, a collection (an ensemble) of forecasts whose members start from slightly different initial conditions is calculated. By varying the initial conditions within their error bars, the sensitivity of the resulting forecasts to these measurement errors can be accounted for. The ensemble approach can also be applied to estimate forecast errors that are due to insufficiently known model parameters by varying these parameters between ensemble members. An important (and difficult) question in ensemble weather forecasting is how well does an ensemble of forecasts reproduce the actual forecast uncertainty. A widely used criterion to assess the quality of forecast ensembles is statistical consistency which demands that the ensemble members and the corresponding measurement (the ``verification\'\') behave like random independent draws from the same underlying probability distribution. Since this forecast distribution is generally unknown, such an analysis is nontrivial. An established criterion to assess statistical consistency of a historical archive of scalar ensembles and verifications is uniformity of the verification rank: If the verification falls between the (k-1)-st and k-th largest ensemble member it is said to have rank k. Statistical consistency implies that the average frequency of occurrence should be the same for each rank. A central result of the present thesis is that, in a statistically consistent K-member ensemble, the (K+1)-dimensional vector of rank probabilities is a random vector that is uniformly distributed on the K-dimensional probability simplex. This behavior is universal for all possible forecast distributions. It thus provides a way to describe forecast ensembles in a nonparametric way, without making any assumptions about the statistical behavior of the ensemble data. The physical details of the forecast model are eliminated, and the notion of statistical consistency is captured in an elementary way. Two applications of this result to ensemble analysis are presented. Ensemble stratification, the partitioning of an archive of ensemble forecasts into subsets using a discriminating criterion, is considered in the light of the above result. It is shown that certain stratification criteria can make the individual subsets of ensembles appear statistically inconsistent, even though the unstratified ensemble is statistically consistent. This effect is explained by considering statistical fluctuations of rank probabilities. A new hypothesis test is developed to assess statistical consistency of stratified ensembles while taking these potentially misleading stratification effects into account. The distribution of rank probabilities is further used to study the predictability of outliers, which are defined as events where the verification falls outside the range of the ensemble, being either smaller than the smallest, or larger than the largest ensemble member. It is shown that these events are better predictable than by a naive benchmark prediction, which unconditionally issues the average outlier frequency of 2/(K+1) as a forecast. Predictability of outlier events, quantified in terms of probabilistic skill scores and receiver operating characteristics (ROC), is shown to be universal in a hypothetical forecast ensemble. An empirical study shows that in an operational temperature forecast ensemble, outliers are likewise predictable, and that the corresponding predictability measures agree with the analytically calculated ones.

Studiens syfte är att med en pragmatisk ansats beskriva och diskutera hur och på vilka grunder behöriga musiklärare väljer repertoar till ensemblespel i årskurs 7 - 9. Genom att beskriva och tolka fyra musiklärares erfarenheter genom innehållsanalys av semi-strukturerade intervjuer kunde studiens resultat presenteras. Resultatet visar att musiklärarna utvecklar genom erfarenheter och reflektion, en förtrogenhet med musikämnet. Musiklärarens egna musikaliska preferenser med influens från kollegor och elevers intressen påverkar urvalet av repertoar. Traditioner, repertoarens popularitet, egenskaper och kopplingar till musikhistoria utgör vanligt förekommande urvalsinstrument till ensemblemomentet. Den faktor för urval som resultatet mest pekar på är repertoarens spelbarhet. Textinnehåll som går emot skolans värdegrund samt soundbaserade låtar blir ofta bortvalda, då resurser att reproducera originalen inte finns i klassrummen. Genom att skapa gemensamma inkörsportar kan eleverna få ett meningsskapande, och genom att elevernas intressen tillgodoses, upplever lärarna att eleverna öppnar upp sig för andra genrer. Det finns en syn på att elevers intresse och motivation antingen ska tändas eller upprätthållas, vilket repertoaren bidrar till. Studiens resultat pekar mot att en ständig kulturell reproduktion pågår inom musikämnet, och med utgångspunkt i pragmatismen går det att konstatera en kanon som är lika dialektal som samhället. / The purpose of this study is to investigate how certificated music teachers select repertoire for ensemble plays in Swedish elementary school classes 7-9. By describing and interpreting the experiences of four music teachers experiences through semi-structured interviews and content analysis, the study's results were presented. Through experience and reflection, music teachers develop a familiarity with the school subject of music. The result shows that the music teacher's personal musical preferences, with the influence of colleagues and students' interests, influence the selection of repertoire. The range of popularity of the repertoire, praxis, attributes of the songs and connections to education of music history is common for selection of repertoire for the moments of ensemble plays. The playability of the repertoire is one of the most showed factors in the selection of repertoire. Content in song lyrics against the school's basic values and sound-based songs are being rejected, as resources to reproduce the sound of the originals are not suitable in the classrooms. Common interests created by the teacher, can create reason for the students that can show their interests for other genres. The repertoire contributes to create and maintain the student’s interests and motivation. Through pragmatism it is possible to establish a canon that is as dialectal as society and that a constant cultural reproduction is ongoing in the field of music.

The two works of Joseph Schwantner which are the focus of this study, are quite unique for this composer. These two pieces represent the only instance in which Schwantner used the same music for two different compositions. From a Dark Millennium, and Sanctuary from the Music of Amber, are identical in musical material, form and length. While From a Dark Millennium was written for a large wind ensemble, Sanctuary was scored for a sextet of flute, clarinet/bass clarinet, violin, cello, piano, and percussion. The comparative analysis of these pieces reveal the essence of the music, as well as explores the scoring of each version. Both the melodic and harmonic material in this music is based almost entirely on an octatonic scale of alternating whole and half steps. Very little musical material is used in these works, however the approach toward expanding this material is exceptionally creative. The music shifts abruptly from sections that are sparse and soloistic, to scoring that is very dense. While the piano is utilized as the central timbre in both versions, the wind ensemble presents a much heavier and more percussive sound throughout. The chamber version, due to its size and instrumentation, is more ethereal, and features the performers in a soloistic environment. In examining both of these works, many of the distinctive traits found in the music of Joseph Schwantner are exhibited. The differences between these two versions help to illustrate his unique approach to composition and orchestration. The two works have also had a significant impact in their respective performance media as well. From a Dark Millennium has become an important part of the repertoire for wind ensembles; and Music of Amber, which won the 1981 Kennedy Center Friedheim Award for excellence in chamber composition, is one of Schwantner's most performed chamber pieces.

The transcription is an addition to the repertoire for brass ensemble and bass trombone. Consideration is given to the nineteenth-century orchestration treatises of Berlioz and Strauss as well as the twentieth-century texts of Erik Leidzén, Walter Piston, and Samuel Adler. The transcription process is shaped by the principles of these writers. The score is contained in the appendix.

Im Jahr 2011 hat die UB Leipzig mit großzügiger Unterstützung durch die Alfried Krupp von Bohlen und Halbach-Stiftung begonnen, Sommerkurse zur Handschriftenkultur anzubieten. Kernpunkt dieser Fortbildungsinitiative für den wissenschaftlichen Nachwuchs war die Erkenntnis, dass sich die Universitäten in den letzten beiden Jahrzehnten stark aus der Vermittlung von Kompetenzen zurückgezogen haben, die für die Arbeit mit den handschriftlichen Quellen grundlegend und unerlässlich sind.

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[pt] Simulação de reservatórios de óleo e gás é uma demanda comum em engenharia de petróleo e pesquisas relacionadas, que pode requerer um elevado custo computacional de tempo e processamento ao resolver um problema matemático. Além disso, alguns métodos de caracterização de reservatórios necessitam múltiplas iterações, resultando em muitas simulações para obter um resultado. Também podemos citar os métodos baseados em conjunto, tais como o ensemble Kalman filter, o EnKF, e o Ensemble Smoother With Multiple Data Assimilation,o ES-MDA, que requerem muitas simulações. Em contrapartida, o uso de aprendizado de máquina cresceu bastante na indústria de energia. Isto pode melhorar a acurácia de predição, otimizar estratégias e outros. Visando reduzir as complexidades de simulação de reservatórios, este trabalho investiga o uso de aprendizado de máquina como uma alternativa a simuladores convencionais. O modelo Random Forest Regressor é testado para reproduzir respostas de pressão em um reservatório multi-região radial composto. Uma solução analítica é utilizada para gerar o conjunto de treino e teste para o modelo. A partir de experimentação e análise, este trabalho tem o objetivo de suplementar a utilização de aprendizado de máquina na indústria de energia. / [en] Oil and gas reservoir simulation is a common demand in petroleum engineering, and research, which may have a high computational cost, solving a mathematical numeric problem, or high computational time. Moreover, several reservoir characterization methods require multiple iterations, resulting in many simulations to obtain a reasonable characterization. It is also possible to mention ensemble-based methods, such as the ensemble Kalman filter, EnKF, and the Ensemble Smoother With Multiple Data Assimilation, ES-MDA, which demand lots of simulation runs to provide the output result. As a result, reservoir simulation might be a complex subject to deal with when working with reservoir characterization. The use of machine learning has been increasing in the energy industry. It can improve the accuracy of reservoir predictions, optimize production strategies, and many other applications. The complexity and uncertainty of reservoir models pose significant challenges to traditional modeling approaches, making machine learning an attractive solution. Aiming to reduce reservoir simulation’s complexities, this work investigates using a machine-learning model as an alternative to conventional simulators. The Random Forest regressor model is experimented with to reproduce pressure response solutions for multi-region radial composite reservoirs. An analytical approach is employed to create the training dataset in the following procedure: the permeability is sorted using a specific distribution, and the output is generated using the analytical solution. Through experimentation and analysis, this work aims to advance our understanding of using machine learning in reservoir simulation for the energy industry.

[pt] O ensemble smoother with multiple data assimilation (ES-MDA) se tornou um poderoso estimador de parâmetros. A principal ideia do ES-MDA é assimilar os mesmos dados com a matriz de covariância dos erros dos dados inflada. Na implementação original do ES-MDA, os fatores de inflação e o número de assimilações são escolhidos a priori. O único requisito é que a soma dos inversos de tais fatores seja igual a um. Naturalmente, escolhendo-os iguais ao número de assimilações cumpre este requerimento. Contudo, estudos recentes mostraram uma relação entre a equação de atualização do ES-MDA com a solução para o problema inverso regularizado. Consequentemente, tais elementos agem como os parâmetros de regularização em cada assimilação. Assim, estudos propuseram técnicas para gerar tais fatores baseadas no princípio da discrepância. Embora estes estudos tenham propostos técnicas, um procedimento ótimo para gerar os fatores de inflação continua um problema em aberto. Mais ainda, tais estudos divergem em qual método de regularização é sufiente para produzir os melhores resultados para o ES-MDA. Portanto, nesta tese é abordado o problema de gerar os fatores de inflação para o ESMDA e suas influências na performance do método. Apresentamos uma análise numérica do impacto de tais fatores nos parâmetros principais do ES-MDA: o tamanho do conjunto, o número de assimilações e o vetor de atualização dos parâmetros. Com a conclusão desta análise, nós propomos uma nova técnica para gerar os fatores de inflação para o ES-MDA baseada em um método de regularização para algorítmos do tipo Levenberg-Marquardt. Investigando os resultados de um problema de inundação de um reservatório 2D, o novo método obtém melhor estimativa tanto para os parâmetros do modelo tanto quanto para os dados observados. / [en] The ensemble smoother with multiple data assimilation (ES-MDA) gained much attention as a powerful parameter estimation method. The main idea of the ES-MDA is to assimilate the same data multiple times with an inflated data error covariance matrix. In the original ES-MDA implementation, these inflation factors, such as the number of assimilations, are selected a priori. The only requirement is that the sum of the inflation factors inverses must be equal to one. Therefore, selecting them equal to the number of assimilations is a straightforward choice. Nevertheless, recent studies have shown a relationship between the ES-MDA update equation and the solution to a regularized inverse problem. Hence, the inflation factors play the role of the regularization parameter at each ES-MDA assimilation step. As a result, they have also suggested new procedures to generate these elements based on the discrepancy principle. Although several studies proposed efficient techniques to generate the ES-MDA inflation factors, an optimal procedure to generate them remains an open problem. Moreover, the studies diverge on which regularization scheme is sufficient to provide the best ES-MDA outcomes. Therefore, in this work, we address the problem of generating the ES-MDA inflation factors and their influence on the method s performance. We present a numerical analysis of the influence of such factors on the main parameters of the ES-MDA, such as the ensemble size, the number of assimilations, and the ES-MDA vector of model parameters update. With the conclusions presented in the aforementioned analysis, we propose a new procedure to generate ES-MDA inflation factors based on a regularizing scheme for Levenberg-Marquardt algorithms. It is shown through a synthetic two-dimensional waterflooding problem that the new method achieves better model parameters and data match compared to the other ES-MDA implementations available in the literature.

Detta självständiga arbete fokuserar på att utforska hur gymnasieelever som läser ett nationellt program med musik som tillval uppfattar ensemblespel. Syftet med arbetet är att bidra med kunskap om hur dessa elever ser på och upplever ensemblespel. För att besvara frågeställningarna användes en kvalitativ metod med fokusgruppsintervjuer för att samla in data från ett homogent urval av elever. Resultatet som besvarar frågeställningarna visar att eleverna beskriver ensemblespel som en möjlighet att utveckla färdigheter i social interaktion, samarbete och ledarskap. Eftersom musik inte är elevernas huvudämne har de sällan samma tid för övning och musikalisk ambition som elever med musik som huvudämne har, vilket gör att en stark gruppdynamik värdesätts högre än speltekniska färdigheter. Det förekommer även gruppdynamiska svårigheter, och resultatet visar på att processen för att ta ett demokratiskt beslut ibland är en orsak till stress inom gruppen. Trots dessa svårigheter är elevernas inställning till ensemblespel positiv och ensemble ses som ett roligt och engagerande komplement till den annars teoretiska skolveckan. Resultatet av detta arbete ger en större inblick i elevernas syn på ensembleundervisning, vilket kan hjälpa musikpedagoger som vill förbättra kvaliteten och tillgängligheten för musikutbildning i gymnasieskolor. / This study focuses on exploring how high school students who are studying a national program with music as an optional subject perceive ensemble classes. The aim of this research is to contribute with knowledge about how these students view and experience ensemble classes. The study employed a qualitative approach, using focus group interviews to collect data from a homogenous sample of students. Findings show that ensemble classes provide the students with opportunities for developing skills in social interaction and teamwork as well as leadership. Since music isn’t their primary subject, they rarely have the same musical competence or time for practice as students with music as primary subject do, which is why a strong group dynamic is highly valued. However, the students also expressed difficulties about said group dynamic, finding the process of a democratic decision to sometimes be a cause of distress within the group. Despite these difficulties the students view ensemble classes in a positive light, seeing them as a fun and engaging complement to the otherwise theoretical school week. The findings of this study focus of the students’ perception of ensemble, which can benefit music educators who seek to improve the quality and accessibility of music education in high schools.