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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
421

Användbarhet hos journalsystem : En fallstudie om upplevd användbarhet hos Cosmic på Akademiska Sjukhuset

Nordlander, Henrik, Mjöberg, Olof January 2019 (has links)
Det har i Sverige gjorts stora åtaganden om att vara världsledande inom digitalisering av vården. Ett av de verktyg som möjliggör för vårdpersonalen att uppnå dessa åtaganden är de digitala journalsystem som idag används. I detta arbete genomför vi en fallstudie i syfte att undersöka hur användarna av det största digitala journalsystemet Cambio Cosmic upplever användbarheten hos systemet samt vilka förändringar och åtgärder som kan öka användbarheten. Datan i studien har insamlats med hjälp av fem intervjuer, tre läkare och två sjuksköterskor vid Akademiska sjukhuset som sedan analyserats utifrån modellen Quality in Use Integrated Measurement(QUIM) om användbarhet. En modell som används för att mäta användbarhet hos ett informationssystem. Resultatet av studien tyder på att Cosmic är användbart, men användbarheten är bristande vad gäller tillgänglighet av information och möjligheter att överblicka relevanta patientdata är undermålig. Studien visar att datorvana inte nödvändigtvis är synonymt med enkelhet att lära sig använda Cosmic, men att datorvana möjliggör en mer intuitiv navigering. Datorvana räcker däremot inte för att användaren ska bemästra Cosmic. Vi identifierar därför behovet av en introduktionsutbildning och regelbunden fortbildning inom systemet. Sett till hur användare söker kunskap om, och lösningar på, problem som kan uppstå i arbetet, försöker de ofta skapa egna lösningar än de Cosmic förser dem med. Vi identifierar i studien att en större delaktighet av användarna i vidareutvecklingen av systemet krävs för att nå bättre användbarhet. Vidare finner vi även att det bör implementeras utbredd funktionalitet och rutiner för återkoppling mellan användarna och ansvariga av systemet. Delaktigheten och återkopplingen ses som nära sammankopplade i resultatet. Återkoppling kan vara en del av, eller i helhet utgöra den delaktighet användarna efterfrågar och studien visar vara nödvändig. Det är dessa faktorer som studien sammanfattningsvis visar vara avgörande för att genom digitala journalsystem göra vården mer effektiv.
422

A study of cosmic ray anisotropies in the heliosphere / Godfrey Sibusiso Nkosi

Nkosi, Godfrey Sibusiso January 2006 (has links)
Thesis (M.Sc. (Physics))--North-West University, Potchefstroom Campus, 2007.
423

Elektronisk journal i kommunal hemsjukvård : en kvantitativ studie om distriktssköterskors och sjuksköterskors kunskap om och förståelse av cambio cosmic

Barrdahl, Åsa, Holmqvist, Camilla January 2015 (has links)
Den elektroniska journalen är en del av distrikts- och sjuksköterskors dagliga arbete och ökar förutsättningen för ett patientsäkert arbete. Distrikts- och sjuksköterskor arbetar efter kärnkompetenserna informatik och säker vård, men brister i den elektroniska journalen kan påverka dessa negativt. Syftet var att undersöka sjuksköterskors och distriktssköterskors kunskap om och förståelse av att använda elektronisk journal i kommunal hemsjukvård. Metod: kvantitativ tvärsnittsstudie. Urvalet bestod av sjuksköterskor och distriktssköterskor från fem kommuner i Kronobergs län (n 67). Datainsamlingen skedde med frågeformulär som analyserades med beskrivande statistik. Resultat: elektroniska journalen ansågs i hög grad vara ett bra stöd i det dagliga arbetet, och bidrog till en god och säker vård. Navigeringen i journalen och informationsöverföring mellan olika vårdgivare innebar oftast inte några större problem. Dubbeldokumentation mellan olika system förekom ofta och kunskap om journalens funktioner saknades. Det var i de flesta fall inte möjligt att använda journalen mobilt i hemsjukvården, trots att behov fanns. Över 80 % uppgav att läkemedelslistan ibland eller sällan var uppdaterad. Dessa brister kan påverka patientsäkerheten negativt eftersom förutsättningen för att bedriva en säker vård är att informationen i journalen är tydlig och korrekt. Studiens resultat kan ligga till grund för fortsatt forskning inom patientsäkerhet och utveckling av journalens användarvänlighet. / The electronic patient record is a part of nurses´ daily work, and increases the premise of patient safety. Nurses work by the core competencies informatics and safety, but flaws in the electronic patient record can affect these adversely. The aim of the study was to investigate the nurses' knowledge and understanding of using electronic patient records in municipal home care. Method: quantitative cross-sectional study. The sample consisted of nurses and district nurses from five municipalities in the county of Kronoberg (n 67). The data collection was done using questionnaires, which were analyzed with descriptive statistics. Results: the electronic patient record was to a high degree considered to be a good support in the daily work, and to contribute to a good and safe care. Navigation in the patient record and transfer of information between different health care providers, was usually not regarded as a major problem. Double documentation between various systems were common. There was a lack of knowledge of the patient record´s functions. It was in most cases not possible to use wireless connections for the patient record in the patient´s home, although the need existed. Over 80 % stated that the medication list was updated sometimes or rarely. These shortcomings can affect patient safety in a negative way, because the prerequisite for providing a safe care is that the information in the patient record is clear and accurate. The results of the study could be the basis for further research in safety, and for the development of the electronic patient record´s usability.
424

Measurement of the cosmic lepton and electron fluxes with the AMS detector on board of the International Space Station. Monitoring of the energy measurement in the calorimeter / Mesure des flux de leptons et d'électrons cosmiques avec le détecteur AMS installé sur la Station Spatiale Internationale. Contrôle in situ de la mesure en énergie du calorimètre.

Tao, Li 06 July 2015 (has links)
Le Spectromètre Magnétique Alpha (AMS) est un détecteur de particules installé à bord de la Station Spatiale Internationale ; il enregistre des données depuis mai 2011. L'expérience a pour objectif d'identifier la nature des rayons cosmiques chargés et des photons et de mesurer leur flux dans la gamme d'énergie du GeV au TeV. Ces mesures permettent d'affiner les modèles de propagation de rayons cosmiques, d'effectuer une recherche indirecte de matière noire, et de chercher l'antimatière primordiale (anti-hélium). Dans ce mémoire, les données des premières années ont été utilisées pour mesurer les flux d'électrons et de leptons (électrons + positons) dans la gamme d'énergie de 0.5 GeV à 700 GeV. L'identification d'électrons nécessite une séparation électrons/protons de l'ordre de 104, obtenue par l'utilisation conjointe des estimateurs de différents sous-détecteurs d'AMS, en particulier du calorimètre électromagnétique (ECAL), du trajectomètre et du détecteur à radiation de transition (TRD). Dans cette analyse, les nombres d'électrons et de leptons sont estimés par un ajustement des distributions de l'estimateur du calorimètre et vérifiés en utilisant l'estimateur du TRD : 11 millions leptons ont été sélectionnés et analysés. Les incertitudes systématiques sont déterminées en variant les coupures de sélection et la procédure d'ajustement. L'acceptance géométrique du détecteur et les efficacités de sélection sont estimées grâce aux données de simulation. Les différences observées sur les échantillons de contrôle issus des données permettent de corriger la simulation. Les incertitudes systématiques associées à ces corrections sont établies en variant les échantillons de contrôle. Au total, à 100 GeV (resp. 700 GeV), l'incertitude statistique du flux de leptons est 2% (30%) et l'incertitude systématique est 3% (40%). Comme les flux se comportent globalement en loi de puissance en fonction de l'énergie, il est important de maitriser la calibration en énergie. Nous avons contrôlé in situ la mesure en énergie du calorimètre en comparant les électrons des données de vol et les données de tests en faisceaux, en utilisant en particulier la variable E/p ou p est la quantité de mouvement mesurée par le trajectomètre. Une deuxième méthode de calibration absolue à basse énergie, indépendante du trajectomètre, basée sur l'effet de la coupure géomagnétique a été développée. Deux modèles de prédiction de la coupure géomagnétique, l'approximation Störmer et le modèle IGRF, ont été testés et comparés. Ces deux méthodes ont permis de contrôler la calibration en énergie à 2% et de vérifier la stabilité des performances du calorimètre dans le temps. / The Alpha Magnetic Spectrometer (AMS) is a particle detector installed on the International Space Station; it starts to record data since May 2011. The experiment aims to identify the nature of charged cosmic rays and photons and measure their fluxes in the energy range of GeV to TeV. These measurements enable us to refine the cosmic ray propagation models, to perform indirect research of dark matter and to search for primordial antimatter (anti-helium). In this context, the data of the first years have been utilized to measure the electron flux and lepton flux (electron + positron) in the energy range of 0.5 GeV to 700 GeV. Identification of electrons requires an electrons / protons separation power of the order of 104, which is acquired by combining the information from different sub-detectors of AMS, in particular the electromagnetic calorimeter (ECAL), the tracker and the transition radiation detector (TRD). In this analysis, the numbers of electrons and leptons are estimated by fitting the distribution of the ECAL estimator and are verified using the TRD estimator: 11 million leptons are selected and analyzed. The systematic uncertainties are determined by changing the selection cuts and the fit procedure. The geometric acceptance of the detector and the selection efficiency are estimated thanks to simulated data. The differences observed on the control samples from data allow to correct the simulation. The systematic uncertainty associated to this correction is estimated by varying the control samples. In total, at 100 GeV (resp. 700 GeV), the statistic uncertainty of the lepton flux is 2% (30%) and the systematic uncertainty is 3% (40%). As the flux generally follows a power law as a function of energy, it is important to control the energy calibration. We have controlled in-situ the measurement of energy in the ECAL by comparing the electrons from flight data and from test beams, using in particular the E/p variable where p is momentum measured by the tracker. A second method of absolute calibration at low energy, independent from the tracker, is developed based on the geomagnetic cutoff effect. Two models of geomagnetic cutoff prediction, the Störmer approximation and the IGRF model, have been tested and compared. These two methods allow to control the energy calibration to a precision of 2% and to verify the stability of the ECAL performance with time.
425

Cosmic metodo taikymas darbo imlumo įvertinimui agile projektuose / Cosmic method usage for job evaluation in agile projects

Ivonytė, Aistė 18 August 2014 (has links)
COSMIC metodas apibrėžia principus, taisykles ir standartinio funkcinio dydžio matavimo procesą. Šio metodo realizacija Agile projektuose, padės prognozuoti konkrečios užduoties atlikimo laiką ankstyvoje planavimo stadijoje. Netikslus darbo imlumo įvertinimas planavimo stadijoje gali tapti rimta problema, dėl ko gali nepavykti įgyvendinti projekto, arba jo dalies, laiku. Vartotojų scenarijai yra vertinami SP, kurie nėra verčiami į laikinę skalę, kas dar labiau apsunkina tikslų darbo imlumo įvertinimą pradinėje projekto ir užduočių planavimo stadijoje. Šiame darbe atliekama detali COSMIC metodo analizė, apžvelgiami esami įrankiai, skirti Agile projektams. Įsitikinama, kad nėra sukurto įrankio, leidžiančio prognozuoti vartotojų scenarijų atlikimo laiką, sujungus COSMIC su istoriniais darbų atlikimo duomenimis. Darbe iškeltų tikslų pasiekimui buvo atliktas trijų dalių eksperimentinis tyrimas kurio metu paaiškėjo, kad COSMIC metodo apjungimas su istoriniais darbų atlikimo duomenimis gali pateikti panašią ar net geresnę prognozę, lyginant su programuotojų komandos įvertinimu. Taip pat pateikiamos idėjos įrankio korekcijai, jos realizuojamos ir kartojamas eksperimentas. Aptariami gauti rezultatai ir pateikiamos išvados. / COSMIC method defines principles, rules and the process of standard functional size measurement. Method implementation in Agile projects will help forecasting the completion time for a specific task in the early planning stages. Inaccurate task capacity estimation in the planning stage can become a serious problem which in turn may lead to not being able to complete parts of the assignment or even the whole project. User stories are being evaluated as SP which are not converted into a timescale which further complicates accurate job receptivity in the early project and task planning stage. Within this paper a detailed COSMIC method analysis is being performed as well as a review of existing Agile project tools. Also making sure that there are no other tools which allow the forecast of user story completion time by merging COSMIC with task completion time history log. To complete the goals of this paper a three part experimental survey took place which determined that the consolidation of the COSMIC method with the task completion time history may result in a similar or even more accurate forecast as compared to the forecast of a team of software developers. Also new ideas for tool adjustments are included, their implementation and repeating of the experiment, review of the obtained results and findings.
426

A study of cosmic ray anisotropies in the heliosphere / Godfrey Sibusiso Nkosi

Nkosi, Godfrey Sibusiso January 2006 (has links)
The three-dimensional (3D) steady-state electron modulation model of Ferreira (2002), based on Parker (1965) transport equation, is used to study the modulation of the 7 MeV galactic and Jovian electron anisotropies in the inner heliosphere. The Jovian electrons are produced in Jupiter's magnetosphere which is situated at ~ 5 AU in the ecliptic plane. The propagation of these particles is mainly described by the diffusion tensor applicable for the inner heliosphere. Some of the elements of the diffusion tensor are revisited in order to establish what contribution they make to the three-dimensional anisotropy vector and its components in the inner heliosphere. The 'drift' term is neglected since the focus of this study is on low-energy electrons. The effects on the electron anisotropy of different scenarios when changing the solar wind speed from minimum to maximum activity is illustrated. The effects on both the galactic and Jovian electron anisotropy of changing the polar perpendicular coefficient, in particular, are illustrated. It is shown that the computed Jovian electron anisotropy dominates the galactic anisotropy close to the Jovian electron source at ~5 AU, as expected, testifying to the validity of the3D-model. For the latitudinal anisotropy, the polar perpendicular diffusion plays a dominant role for Jovian electrons close to the source, with the polar gradient becoming the dominant factor away from the electron source. Of all three anisotropy components, the azimuthal anisotropy is dominant in the equatorial plane close to the source. It is found that there is a large azimuthal gradient close to the source because the low-energy electrons tend to follow the heliospheric magnetic field more closely than higher energy particles. The transition of the solar wind speed from minimum to intermediate to maximum solar activity condition was used to illustrate the modulation of the magnitude of the 7 MeV total anisotropy vector along the Ulysses trajectory. It was found that during the two encounters with the planet a maximum anisotropy of 38% was computed but with different anisotropy-timepeaks as the approach to Jupiter was different. / Thesis (M.Sc. (Physics))--North-West University, Potchefstroom Campus, 2007.
427

A study of cosmic ray anisotropies in the heliosphere / Godfrey Sibusiso Nkosi

Nkosi, Godfrey Sibusiso January 2006 (has links)
The three-dimensional (3D) steady-state electron modulation model of Ferreira (2002), based on Parker (1965) transport equation, is used to study the modulation of the 7 MeV galactic and Jovian electron anisotropies in the inner heliosphere. The Jovian electrons are produced in Jupiter's magnetosphere which is situated at ~ 5 AU in the ecliptic plane. The propagation of these particles is mainly described by the diffusion tensor applicable for the inner heliosphere. Some of the elements of the diffusion tensor are revisited in order to establish what contribution they make to the three-dimensional anisotropy vector and its components in the inner heliosphere. The 'drift' term is neglected since the focus of this study is on low-energy electrons. The effects on the electron anisotropy of different scenarios when changing the solar wind speed from minimum to maximum activity is illustrated. The effects on both the galactic and Jovian electron anisotropy of changing the polar perpendicular coefficient, in particular, are illustrated. It is shown that the computed Jovian electron anisotropy dominates the galactic anisotropy close to the Jovian electron source at ~5 AU, as expected, testifying to the validity of the3D-model. For the latitudinal anisotropy, the polar perpendicular diffusion plays a dominant role for Jovian electrons close to the source, with the polar gradient becoming the dominant factor away from the electron source. Of all three anisotropy components, the azimuthal anisotropy is dominant in the equatorial plane close to the source. It is found that there is a large azimuthal gradient close to the source because the low-energy electrons tend to follow the heliospheric magnetic field more closely than higher energy particles. The transition of the solar wind speed from minimum to intermediate to maximum solar activity condition was used to illustrate the modulation of the magnitude of the 7 MeV total anisotropy vector along the Ulysses trajectory. It was found that during the two encounters with the planet a maximum anisotropy of 38% was computed but with different anisotropy-timepeaks as the approach to Jupiter was different. / Thesis (M.Sc. (Physics))--North-West University, Potchefstroom Campus, 2007.
428

Uma Abordagem Comparativa entre duas Técnicas de Medição de Software

BARBALHO, Felipe de Oliveira 28 April 2014 (has links)
Submitted by Irene Nascimento (irene.kessia@ufpe.br) on 2017-03-08T19:19:52Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Dissertação_FelipeOliveiraBarbalho.pdf: 1338681 bytes, checksum: 59450531ef14c232cbd53efcacba8b7e (MD5) / Made available in DSpace on 2017-03-08T19:19:52Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Dissertação_FelipeOliveiraBarbalho.pdf: 1338681 bytes, checksum: 59450531ef14c232cbd53efcacba8b7e (MD5) Previous issue date: 2014-04-28 / Há uma tendência das organizações que atuam no desenvolvimento e manutenção de software em utilizarem Pontos de Função como medida padrão em seus processos de medição. Atualmente a análise de pontos de função é a técnica mais utilizada entre as organizações brasileiras. Por outro lado, o COSMIC é uma técnica de medição considerada como a segunda geração em método de medição funcional de projetos de desenvolvimento e manutenção de software, sendo precisa e abrangente para medir software e estimar esforço de desenvolvimento, despertando o interesse do mercado de desenvolvimento de software por essa métrica. Quando considerada a migração das bases históricas de medição de software das organizações para uma nova unidade de medida, há como consequência um alto custo para se medir os projetos legados. Nesse sentido, o objetivo desse trabalho é propor uma alternativa para migração de bases históricas de Pontos de Função para o COSMIC. A abordagem propõe uma fórmula de conversão, o qual foi encontrada a partir da medição de quatro projetos de desenvolvimento de software analisados nessas duas técnicas, para atualizar seus dados sem o custo de refazer toda sua base histórica. / There is a tendency in software development and maintenance organizations in using Function Points as a standard measure in their measurement processes. Currently the analysis of function points is the most used technique among Brazilian organizations. On the other hand, COSMIC is a measurement technique considered as the secondgeneration method of functional measurement for software development and maintenance projects, with an accurate and comprehensive approach to measure and estimate software development effort, arousing interest of software development market for this metric. When organizations are considering the migration of their historical measure basis for a new measurement unit, there is a consequent high cost to measure the legacy projects. In this sense, the purpose of this work is to propose an alternative to migrate historical bases of Function Points to COSMIC. The approach proposes a conversion factor, which was found from the measurement of four software development projects analyzed in these two techniques to update its data without the cost of redoing the entire historical basis.
429

Impacto de estações irregulares sobre a reconstrução de eventos do Observatório Pierre Auger / Impact of irregular stations on the event reconstruction of the Pierre Auger Observatory

Daniel, Bruno, 1987 05 July 2012 (has links)
Orientadores: Ernesto Kemp, Anderson Campos Fauth / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Física Gleb Wataghin / Made available in DSpace on 2018-08-20T22:56:12Z (GMT). No. of bitstreams: 1 Daniel_Bruno_M.pdf: 8374007 bytes, checksum: 352eb3cb6108ee55f40579c9db6d47a4 (MD5) Previous issue date: 2012 / Resumo: O Observatório Pierre Auger foi desenvolvido com o objetivo de estudar os raios cósmicos de energia ultra-alta (maior que 10¹8 eV ), cujo fluxo é extremamente baixo. Sua configuração híbrida consiste em 1600 detectores de radiação Cherenkov, produzida pela passagem de partículas dos chuveiros atmosféricos na água, e 4 estações com telescópios de fluorescência, que detectam a emissão de luz que ocorre após a excitação das moléculas de nitrogênio da atmosfera. O observatório cobre uma área de cerca de 3000 km² . Neste trabalho será feita uma descrição detalhada dos detectores de superfície e de seu procedimento de reconstrução de eventos, no qual são determinadas a energia e direção de chegada do raio cósmico primário. Serão mostrados alguns resultados da caracterização e teste do tanque Cherenkov de Campinas e análises realizadas sobre o procedimento de reconstrução, nas quais são estudadas as consequências da exclusão de uma estação e o impacto da utilização de tanques irregulares, com fotomultiplicadoras de ganho alterado ou desligadas. Os resultados destes estudos mostram que os procedimentos de calibração e seleção de eventos atualmente utilizados no Observatório Pierre Auger são eficientes, garantindo a qualidade dos dados, mas que algumas modificações poderiam trazer um aumento na taxa de detecção, e também que a configuração mencionada em algumas propostas de expansão do observatório, com apenas uma fotomultiplicadora por tanque, pode reduzir a confiabilidade dos eventos / Abstract: The Pierre Auger Observatory was designed to study the ultra-high energy (> 10¹8 eV ) cosmic rays, whose flux is extremely low. Its hybrid configuration consists on 1600 detectors of Cherenkov radiation, produced by the passage of particles from the air showers by water, and 4 fluorescence telescope stations, to detect light emitted after the excitation of nitrogen molecules of the atmosphere. The observatory covers an area of 3000 km² . This work will give a detailed description of the surface detectors and its event reconstruction procedure, where the energy and arrival direction of the primary cosmic ray is determined. Some results of the characterization and test of the Cherenkov tank of Campinas will be showed, and also some analysis about the reconstruction, with studies of the consequences of the exclusion of a station and the impact of the use of irregular tanks, with photomultiplier\\\'s operating in low gain or turned of. This studies show that the calibration and event selection procedures used at the Pierre Auger Observatory are efficient, providing high quality for the data taken, but some modifications could bring an increase of the detection rate. It is also shown that the configuration for the tanks mentioned in some proposals of expansion of the observatory, with a single photomultiplier by tank, could reduce the con#ability of the events / Mestrado / Física / Mestre em Física
430

Measurement of the cosmic lepton and electron fluxes with the AMS detector on board of the International Space Station. Monitoring of the energy measurement in the calorimeter / Mesure des flux de leptons et d'électrons cosmiques avec le détecteur AMS installé sur la Station Spatiale Internationale. Contrôle in situ de la mesure en énergie du calorimètre.

Tao, Li 06 July 2015 (has links)
Le Spectromètre Magnétique Alpha (AMS) est un détecteur de particules installé à bord de la Station Spatiale Internationale ; il enregistre des données depuis mai 2011. L'expérience a pour objectif d'identifier la nature des rayons cosmiques chargés et des photons et de mesurer leur flux dans la gamme d'énergie du GeV au TeV. Ces mesures permettent d'affiner les modèles de propagation de rayons cosmiques, d'effectuer une recherche indirecte de matière noire, et de chercher l'antimatière primordiale (anti-hélium). Dans ce mémoire, les données des premières années ont été utilisées pour mesurer les flux d'électrons et de leptons (électrons + positons) dans la gamme d'énergie de 0.5 GeV à 700 GeV. L'identification d'électrons nécessite une séparation électrons/protons de l'ordre de 104, obtenue par l'utilisation conjointe des estimateurs de différents sous-détecteurs d'AMS, en particulier du calorimètre électromagnétique (ECAL), du trajectomètre et du détecteur à radiation de transition (TRD). Dans cette analyse, les nombres d'électrons et de leptons sont estimés par un ajustement des distributions de l'estimateur du calorimètre et vérifiés en utilisant l'estimateur du TRD : 11 millions leptons ont été sélectionnés et analysés. Les incertitudes systématiques sont déterminées en variant les coupures de sélection et la procédure d'ajustement. L'acceptance géométrique du détecteur et les efficacités de sélection sont estimées grâce aux données de simulation. Les différences observées sur les échantillons de contrôle issus des données permettent de corriger la simulation. Les incertitudes systématiques associées à ces corrections sont établies en variant les échantillons de contrôle. Au total, à 100 GeV (resp. 700 GeV), l'incertitude statistique du flux de leptons est 2% (30%) et l'incertitude systématique est 3% (40%). Comme les flux se comportent globalement en loi de puissance en fonction de l'énergie, il est important de maitriser la calibration en énergie. Nous avons contrôlé in situ la mesure en énergie du calorimètre en comparant les électrons des données de vol et les données de tests en faisceaux, en utilisant en particulier la variable E/p ou p est la quantité de mouvement mesurée par le trajectomètre. Une deuxième méthode de calibration absolue à basse énergie, indépendante du trajectomètre, basée sur l'effet de la coupure géomagnétique a été développée. Deux modèles de prédiction de la coupure géomagnétique, l'approximation Störmer et le modèle IGRF, ont été testés et comparés. Ces deux méthodes ont permis de contrôler la calibration en énergie à 2% et de vérifier la stabilité des performances du calorimètre dans le temps. / The Alpha Magnetic Spectrometer (AMS) is a particle detector installed on the International Space Station; it starts to record data since May 2011. The experiment aims to identify the nature of charged cosmic rays and photons and measure their fluxes in the energy range of GeV to TeV. These measurements enable us to refine the cosmic ray propagation models, to perform indirect research of dark matter and to search for primordial antimatter (anti-helium). In this context, the data of the first years have been utilized to measure the electron flux and lepton flux (electron + positron) in the energy range of 0.5 GeV to 700 GeV. Identification of electrons requires an electrons / protons separation power of the order of 104, which is acquired by combining the information from different sub-detectors of AMS, in particular the electromagnetic calorimeter (ECAL), the tracker and the transition radiation detector (TRD). In this analysis, the numbers of electrons and leptons are estimated by fitting the distribution of the ECAL estimator and are verified using the TRD estimator: 11 million leptons are selected and analyzed. The systematic uncertainties are determined by changing the selection cuts and the fit procedure. The geometric acceptance of the detector and the selection efficiency are estimated thanks to simulated data. The differences observed on the control samples from data allow to correct the simulation. The systematic uncertainty associated to this correction is estimated by varying the control samples. In total, at 100 GeV (resp. 700 GeV), the statistic uncertainty of the lepton flux is 2% (30%) and the systematic uncertainty is 3% (40%). As the flux generally follows a power law as a function of energy, it is important to control the energy calibration. We have controlled in-situ the measurement of energy in the ECAL by comparing the electrons from flight data and from test beams, using in particular the E/p variable where p is momentum measured by the tracker. A second method of absolute calibration at low energy, independent from the tracker, is developed based on the geomagnetic cutoff effect. Two models of geomagnetic cutoff prediction, the Störmer approximation and the IGRF model, have been tested and compared. These two methods allow to control the energy calibration to a precision of 2% and to verify the stability of the ECAL performance with time.

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