Dans le cadre de la chromodynamique quantique, le nucléon est décrit comme constitué de trois quarks de valence plongés dans une mer virtuelle de paires de quark-antiquark et de gluons. L'étrangeté est la plus légère des saveurs n'ayant pas de contribution de valence. Elle est de ce fait un excellent candidat pour étudier cette mer, dont le rôle bien qu'important reste peu compris. La contribution du quark étrange aux distributions de charge et de magnétisation du nucléon est accessible par des mesures d'asymétries de violation de parité en diffusion élastique d'électrons polarisés sur cible de nucléon. Un programme expérimental mondial, dans lequel se place l'expérience G0, est engagé dans ce but. Cette expérience et l'analyse des résultats de sa première phase aux angles avant constituent l'objet de cette thèse.<br /><br />Ce document présente les motivations physiques et les différentes signatures de l'étrangeté aux propriétés du nucléon (masse, spin, impulsion). Nous développons le formalisme de la sonde électro-faible et de ses facteurs de forme, puis le principe de la mesure d'asymétrie de violation de parité. Suit une description du dispositif expérimental, mis en place dans le Hall C du Jefferson Laboratory (Newport-News, USA) ; celui-ci étant conçu pour mesurer sur un large domaine en quadri-moment transféré de 0.1 à 1 (GeV/c)2 des asymétries de l'ordre de 10-6 avec une précision relative de 5 à 10 %. Nous détaillons ensuite toutes les étapes d'analyse permettant de passer des taux de comptage mesurés à une asymétrie physique de violation de parité, en soulignant le travail mené pour estimer les erreurs systématiques. Les résultats de la première phase aux angles avant, puis leur mise en contexte avec les autres expériences et le cadre théorique sont finalement présentés. Nous montrons alors qu'une contribution non nulle des paires de quark-antiquark étranges est favorisée.

ALICE est le détecteur du LHC dédié à l'étude des collisions d'ions lourds ultra-relativistes. Le principal objectif de cette expérience est la mise en évidence et l'étude d'une nouvelle phase de la matière nucléaire prédite par la théorie de la chromodynamique quantique (QCD) : le Plasma de Quarks et de Gluons (PQG). Une des signatures possibles est la suppression des taux de production des quarkonia par écrantage de couleur dans les collisions d'ions lourds, dans lesquelles la formation d'un plasma est attendue. Le spectromètre à muons permettra de mesurer les taux de production des quarkonia (J/Psi, Upsilon) dans les collisions d'ions lourds via leur canal de désintégration dimuonique. Un système de déclenchement rapide, associé au spectromètre à muons, est chargé de sélectionner les événements contenant au minimum un muon ou un dimuon à l'aide d'un algorithme de recherche de traces. L'étude des performances du système de déclenchement du spectromètre à muons, réalisée à l'aide de simulations Monte-Carlo, sera présentée dans ce mémoire en mettant l'accent sur l'efficacité et la fréquence de déclenchement du système dans le cas des collisions Pb-Pb et Ar-Ar. Nous présenterons également la reconstruction du spectre en masse des dimuons de signes opposé avec le spectromètre à muons d'ALICE. A partir de ce spectre, les taux de production des états Upsilon seront extraits pour un mois de collisions Pb-Pb au LHC et pour diverses tranches en centralité.

Syfte – Studiens syfte är att undersöka hybridapplikationers prestanda i olika situationer för att ta reda på varför de upplevs som långsamma. För att uppnå syftet besvaras följande frågeställningar: Hur presterar hybridapplikationer jämfört med nativapplikationer beräkningsmässigt Är JavaScript-biblioteken anledningen till hybridapplikationers sämre prestanda, och vilket av de bibliotek som undersöks är det mest lämpade för bästa prestanda? Kan hybridapplikationer hantera stora datamängder med IndexedDB utan att bli oresponsiva? Metod – Studien använder sig av en experimentell forskningsmetod där hypoteser och förutsägelser formuleras och sedan testas för att besvara frågeställningarna. Resultat – Resultatet från studien visar att prestandan för mobila hybrid-applikationer är i de flesta fall, vid utförande av samma uppgift, underlägsen den för dess motsvarande nativapplikationer. Resultaten visar även att prestandan påverkas av vilket JavaScript-bibliotek som används men att biblioteken inte är anledningen till hybridapplikationers långsamma prestanda. Vidare visar resultaten att hybridapplikationer kan hantera stora datamängder utan att bli oresponsiva. Implikationer – Studien bidrar till att bredda den kunskapsbas som finns om hybridapplikationers prestanda och ger framtida forskning referensdata att bygga vidare på. Studien påvisar dessutom att hybridapplikationer fortfarande är ett alternativ, i synnerhet för företag som vill spara tid och som ej kräver applikationer som utför tunga beräkningar. Begränsningar – Användandet av applikationer som sannolikt inte förekommer i ett verklighetstroget scenario bidrog till resultat som inte har stor relevans inom de användningsområden som finns för hybridapplikationer. / Purpose – The purpose of this thesis is to examine the performance of hybrid mobile applications in different situations to find out why they are perceived as slow. To fulfill the purpose, the following research questions will be answered: How do hybrid applications perform compared to native applications computationally? Are the JavaScript-libraries the reason behind the slower performance of hybrid applications, and which one of the libraries that are examined is most suitable for the best performance? Can hybrid applications manage large amounts of data with IndexedDB without getting unresponsive? Method – The study uses an experimental research method where hypotheses and predictions are formulated and later tested to answer the research questions. Results – The results show that the performance of mobile hybrid applications are in most cases, when performing the same task, inferior to that of corresponding native applications. The results also show that the performance is affected by which JavaScript-library that is being used, but that it is not the main reason for hybrid applications poor performance. They also show that hybrid applications can manage large amounts of data without becoming unresponsive. Implications – The study contributes to broadening the knowledge available on the performance of mobile hybrid applications and provides future research with reference data to build upon. The study also demonstrate that hybrid applications still is an alternative, especially for enterprises who want to save time and does not demand applications that perform heavy computations. Research limitations – The use of applications that most likely would not occur in a realistic scenario contributed with results that have little relevance in the areas of use that exists for hybrid applications.

This thesis consists of two parts. The first part is on fractional factorial design, and the second part is on computer experiment. The first part has two chapters. In the first chapter, we use the concept of conditional main effect, and propose the CME analysis to solve the problem of effect aliasing in two-level fractional factorial design. In the second chapter, we study the conversion rates of a system of webpages with the proposed funnel testing method, by using directed graph to represent the system, fractional factorial design to conduct the experiment, and a method to optimize the total conversion rate with respect to all the webpages in the system. The second part also has two chapters. In the third chapter, we use regression models to quantify the model form uncertainties in the Perez model in building energy simulations. In the last chapter, we propose a new Gaussian process that can jointly model both point and integral responses.

Aerospace Engineering / The aim of this thesis is to explore the high strain rate behavior of metallic specimens using electromagnetic inductive loading as the means to inflict the required high strain rate deformation on laboratory scale specimens, allowing for controlled, repeatable experiments to be performed. Three separate experiments were designed and performed, using helical and spiral coils as the sources of radial and unidirectional loading. The first experiment evaluated the effect of applying a polymer coating on 30.5 mm diameter, Al 6061- O tube samples, in two lengths, 18 and 36 mm. The expanding tube experiment was used to apply a radial loading on the specimens and record the event. Several optical techniques were then used to evaluate the behavior of the samples. Coatings of polyurea and polycarbonate were used. It was observed that the polycarbonate coating seemed to have a more profound effect on the behavior of the metal, by applying a larger restraining pressure on the tube surface during the expansion process, and thereby modifying the stress state of the specimen. The second experiment looked to design an experimental arrangement to test the plane strain, high strain rate behavior of Al 6061-O tubes of different lengths. A 112 mm long solenoid was designed and manufactured, and testing was performed on 30.5 mm diameter Al 6061-O tubes in lengths of 50, 70 and 90 mm. It was observed that the coil behaved similar to shorter ones at low voltages and that the longer the specimen used, the more its deformation path approached a plane strain condition. Finally, a third experiment was performed to develop an experiment to accelerate a plate to high linear velocities, as a means to evaluate the use of a flat spiral coil as the driver for future experiments based upon electromagnetic inductive loading. A prototype coil was manufactured and installed into a converted expanding tube experimental setup. Three samples were tested in several sizes, and materials: aluminum and steel. Speeds in the range of 45 to 251 m/s were obtained, validating the apparatus as a viable method to provide a unidirectional loading. / text

published_or_final_version / Architecture / Master / Master of Architecture

No description available.

Ce travail présente la mesure de la section efficace différentielle du boson Z en impulsion transverse (ptz), dans le canal de désintégration electron-positron, avec le détecteur ATLAS au LHC. La mesure utilise 4.64 inverse fb de données de collisions proton-proton, prises en 2011 avec une énergie du centre de masse de 7 TeV. Le résultat est combiné avec une mesure indépendante faite dans le canal muon-antimuon. La mesure est faite jusqu'à ptz = 800 GeV, et a une incertitude typique de 0.5 % pour ptz < 60 GeV, atteignant jusqu'à 5 % vers la fin du spectre. La mesure est comparée avec modèles théoriques et prédictions des générateurs Monte Carlo.

This thesis is about the demography of the tunicate Styela clava, a species of some notoriety because of its invasiveness and impacts in many parts of the world. Species assemblages have continuously changed throughout evolutionary history, but the rate of today’s anthropogenically facilitated dispersal is unparalleled in history. Non-indigenous species (NIS) are now considered one of the most important risks to native biodiversity. NIS become invasive by becoming both widespread and locally dominant. This requires that a species becomes established, spreads locally, and increases in abundance. In the early stages of invasion, its demography and life history characteristics are of crucial importance. In New Zealand, Styela has established populations in several places, but none of these populations has yet reached the high densities found in other countries. In Lyttelton Port, where this study was located, Styela was first noticed in 2005. It therefore presented an ideal situation to study an invasive species in its early stages of establishment and provided a potentially good model for understanding how invasive species get local traction and spread from initial infestation points. Therefore, I set out to determine demographic features of Styela to understand the numbers game of population dynamics. This study used empirical data on growth rates, size-frequencies through time, and size and age to maturity to test several models, including von Bertalanffy, Logistic dose-response, Ricker and power models of individual growth. The most useful proved to be the von Bertalanffy model. Styela individuals shrink frequently, so average growth rates were often quite low, even though some individuals reached 160 mm or more in total length. Mortality was greatest in summer, presumably after reproduction, and lowest in winter. Fewer than 5% of individuals survived 12 months, and most or all of these died soon afterwards. Populations were, therefore, essentially annual. Recruitment was difficult to determine because of the cryptic nature of small juveniles. However, size-frequency, abundance and mortality data indicated that recruitment most likely occurred in early spring (late-October), and then again in late summer, with growth to maturity (at c. 50 mm total length) within < 5 months. Several manipulative experiments showed that Styela did not readily capitalise on provision of free space but the other non-native ascidian, Ciona intestinalis, rapidly recruited. Transplants of Styela were greatly affected by C. intestinalis, which overgrew them, similar to a localised replacement of Styela by Ciona seen overseas. Lefkovitch modelling was used to test whether Styela had an “Achilles heel” in its life history, whereby managed removal could impact future populations. This showed that under several scenarios intervention would most likely be ineffectual. Overall, this study showed that the original populations in Lyttelton Port are either static or in decline, somewhat contrary to original expectations. Nevertheless, it appears that these small populations may be acting as stepping stones for spread of this species outside of the port.

Stress and time pressure is more present in todays labor markets. In financial markets a securities broker is forced to take decisions on investments under high cognitive load and under extreme time pressure. The research of decision under risk gained new ground with the development of the prospect theory and gave us new insights to the decision making of men. Prospect theory has shown that people are risk seekers when dealing with loss decisions and risk avert when dealing with profit decisions. The value function are defined over gains and losses. Losses looms larger then gains. Although much research conducted on the decision making under risk no previous research have been done showing how time pressure affects decision at risk by using skin conductance. This paper aimed through a randomized experiment with 23 participants examine how time pressure affects individuals' decisions related to risk. Furthermore, it intends to analyze whether time pressure mediate a possible effect of stress by using skin conductance. The results show that there is an increase in risk aversion for gains. This risk aversion was also statistically significant at the 1% level when each participant's responses were used and almost at 5% level when the mean values from each participant was used. Upon loss a risk -seeking behavior could be noticed but it was not statistically significant at the 5 % level. Stress levels as measured by skin conductance showed that the time-pressed group showed signs of stress. However, no stress data was significant at the 5 % level. / Stress och tidspress är idag allt mer närvarande på arbetsmarknaden. På de finansiella marknaderna kan en värdepappersmäklare tvingas ta beslut om investeringar under hög kognitiv belastning och under en extrem tidspress. Forskningen av beslut under risk har genom prospect theory gett oss nya insikter om vilka beslut vi människor tar. Prospect theory har visat att människor är risksökande vid förlustfrågor och riskaversiva vid vinstfrågor. Prospect theorys värdefunktion är definierad över vinst och förlust. Förluster väger tyngre än vinster. Trots att mycket forskning genomförts på beslut vid risk har ingen tidigare forskning hur tidspress påverkar beslut vid risk med hjälp av hudkonduktans tidigare genomförts. Denna uppsats hade som mål att genom ett randomiserat experiment med 23 deltagare undersöka hur tidspress påverkar individers beslut kopplade till risk. Vidare är syftet att också analysera om upplevd stress medierar en eventuell effekt av tidspress genom att använda hudkonduktans. Resultatet visar att det finns en ökad riskaversion vid vinstfrågor. Denna riskaversion var även statistiskt säkerställd på 1% nivå när varje deltagares svar användes och nästan på 5% nivå då medelvärden från varje deltagare användes. Vid förlustfrågor fanns ett risksökande beteende men den var ej statistiskt säkerställd på 5% nivå. Stressnivåerna som uppmättes med hudkonduktans visade att den tidspressade gruppen blev stressade. Dock var inga stressdata signifikanta på 5% nivå.