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Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal

The current study aims to investigate the feasibility of international apparel and footwear retailers to expand their business in Pakistan and compete with other brands. It also highlights the business opportunities in Pakistan apparel retail sector and the motivations of international brands behind expansions. This study was conducted with the help of interviews based on diamond model of Porter, and Hofsetede cultural dimensions. The open ended questions were delivered to the professionals electronically while interviews were conducted by telephone. Seven companies from Pakistan were selected for study purpose. Data was analyzed and assessed manually. The study revealed that there is a significant opportunity for international apparel retailers to launch their retail outlets in Pakistan along with some risks. International brands which are financially strong can tackle these risks. However it was concluded that the companies with less financial strength may find it difficult to go in a new market within 5 years. UK brands are already there and brands from other countries are also opening. Overall Pakistan retail sector is growing and people are becoming fashion conscious. This study provides information to International apparel brands which they can take into consideration while entering Pakistan's apparel retail market. It also gives an opportunity for assessment of market in the light of theoretical modules and shows a direction of getting better market share by launching.

In this Master thesis, we use a singular and regular perturbation theory to derive an analytic approximation formula for the expected discounted penalty function. Our model is an extension of Cramer–Lundberg extended classical model because we consider a more general insurance risk model in which the compound Poisson risk process is perturbed by a Brownian motion multiplied by a stochastic volatility driven by two factors- which have mean reversion models. Moreover, unlike the classical model, our model allows a ruin to be caused either by claims or by surplus’ fluctuation. We compute explicitly the first terms of the asymptotic expansion and we show that they satisfy either an integro-differential equation or a Poisson equation. In addition, we derive the existence and uniqueness conditions of the risk model with two stochastic volatilities factors.

Quantum Field Theory (QFT) provides the essential background for formulating the standard model of elementary particles and, moreover, practically all other theories attempting to explore the physical laws of nature at the sub-atomic level. One of the main observables in QFT are the scattering amplitudes, physical quantities which encode the information of the scattering process of particles. Accordingly, having authentic, well-defined and feasible prescriptions for the calculations of amplitudes is of huge importance to theoretical physicists. Actual calculations show that the text-book prescription, the Feynman method, besides in general being very cumbersome also hides some of the beautiful mathematical features of amplitudes. The last decade has seen tremendous efforts and achievements to improve such calculations, particularly in supersymmetric gauge theories, which have also led to better understanding of QFT itself. Among the known physically and mathematically interesting quantum field theories is perturbative gravity and its supersymmetric version, N=8 supergravity- much less understood than gauge theory. Following the developments in gauge theory, this dissertation mainly aims at exploring scattering amplitudes in gravity as a quantum field theory, using the modern approaches to QFT. The goal is not only to improve our understanding of gravity amplitudes by applying part of the known modern methods of calculations to it but also to introduce and develop new ones.

We study the (strong-)Gibbsian character on R Z d of the law at time t of an infinitedimensional gradient Brownian diffusion / when the initial distribution is Gibbsian.

In this project, we examine how integration over matrices is performed. We investigate and develop a method for calculating matrix integrals over the set of real square matrices. Matrix integrals are used for calculations in several different areas of physics and mathematics; for example quantum field theory, string theory, quantum chromodynamics, and random matrix theory. Our method consists of ways to apply perturbative Taylor expansions to the matrix integrals, reducing each term of the resulting Taylor series to a combinatorial problem using Wick's theorem, and representing the terms of the Wick sum graphically with the help of Feynman diagrams and fat graphs. We use the method in a few examples that aim to clearly demonstrate how to calculate the matrix integrals. / I detta projekt undersöker vi hur integration över matriser genomförs. Vi undersöker och utvecklar en metod för beräkning av matrisintegraler över mängden av alla reell-värda kvadratiska matriser. Matrisintegraler används för beräkningar i ett flertal olika områden inom fysik och matematik, till exempel kvantfältteori, strängteori, kvantkromodynamik och slumpmatristeori. Vår metod består av sätt att applicera perturbativa Taylorutvecklingar på matrisintegralerna, reducera varje term i den resulterande Taylorserien till ett kombinatoriellt problem med hjälp av Wicks sats, och att representera termerna i Wicksumman grafiskt med hjälp av Feynmandiagram. Vi använder metoden i några exempel som syftar till att klart demonstrera hur beräkningen av matrisintegraler går till.

Invasive species are problematic but their control can be difficult. When the history and dynamics of invasive populations are unknown, analytical techniques utilising genetic data can provide information to management. The application of these techniques has typically been limited to species with restricted dispersal or to localised geographic scales. Here these techniques are used in conjunction with traditional approaches to study the invasion of a highly vagile species over a continental scale. Originally introduced to eastern Australia, the common starling (Sturnus vulgaris) is expanding westward and has reached the southeast agricultural region of Western Australia (WA). Spatial, temporal and museum samples representing historical incursions into WA were used in genetic analyses to answer questions important to WA management agencies. Where possible, multiple marker classes were used to evaluate their relative ability to address these questions, including microsatellites, mitochondrial DNA (mtDNA), and a nuclear gene. Between two and four genetic groups were identified in Australia, and the localities on the edge of the range expansion (ERE) were consistently genetically differentiated from all others. Levels of genetic exchange between groups appeared to be low, suggesting that localised control may be effective. Analyses of historical samples indicated patterns of genetic exchange are temporally stable. This suggests that starlings will continue to arrive from the east, requiring vigilance from management. Consistently, a negative relationship was found between genetic diversity and date of first record, which may help in the future to distinguish ineffective surveillance from recent colonisations. Genetic evidence of female-biased dispersal indicated that control strategies preferentially targeting females may more efficiently limit dispersal than those targeting both sexes equally. Variants private to particular genetic groups were identified; tracking the spread of these variants may assist future monitoring programs in understanding ongoing exchange between groups. One mtDNA variant private to ERE localities showed dramatic temporal change, which could not be adequately explained by genetic drift or admixture, but may be explained by selection. Microsatellites were most useful in determining origins and identifying dispersers, mtDNA sequences provided a unique tool for ongoing monitoring of dispersal, and nuclear sequences had high levels of gene diversity and resolution of population structure.

With the high costs of flight testing, especially at hypersonic speeds, ground based facility testing of scramjets becomes an attractive option. The expansion tube is the only facility currently that can offer full flight property duplication at the total pressures and total enthalpies required, while maintaining correct chemical composition. Due to difficulties with short test times and unsteady flow phenomena, scramjet testing in these facilities has not been thoroughly investigated. This study examines these issues, in order to explore the practicality of testing a full ’tip to tail’ scramjet engine at a true flight replication condition in an expansion tube facility. An investigation was initially undertaken on the large X3 expansion tunnel facility to maximise test time and core flow, aimed at producing a 30 km altitude, Mach 10 flow condition. This was identified as the limitation point of the T4 reflected shock tunnel, which has generally been accepted to produce reliable scramjet data for propulsion tests. Using a condition that is also able to be produced in the T4 facility, will permit direct comparison of data between the two facilities in the future, providing confidence in results from expansion tube facilities. Both experimental measurements and numerical calculations showed that the limitation of the test time was due to large boundary layer growth after transition, which engulfed the entire core flow 200 μs into the test time. This phenomenon is likely to affect all scramjet duplication conditions in expansion tubes, as the flow properties are conducive to boundary layer transition occurring. Two solutions where proposed and investigated in order to overcome the flow disruption caused by boundary layer transition; the use of a steady expansion nozzle at the acceleration tube exit; the use of hydrogen as an accelerator gas. Since the smaller X2 facility had a Mach 10 steady expansion nozzle and X3 was decommissioned for the free piston driver to be upgraded, the investigation was shifted to X2. Due to a restricted test time of 550 μs, the static pressure of the flow condition was increased to allow a reduction in the length of the scramjet (pressure-length scaling). A combination of experimental and numerical calculations of the facility was used to define the flow properties. With the confidence of overcoming the phenomenon associated with boundary transition in the X2 facility, numerical modelling of the X3 facility with a steady expansion nozzle was then undertaken to show a 1 ms condition could be produced. Although initially promising, the hydrogen accelerator gas solution requires further investigation. A two dimensional scramjet was designed with upstream injection for testing in X2. This was a three shock inlet with a constant area combustor and a planar thrust surface. Since the flow condition involved changes in flow properties during the test time, aninvestigation of the appropriateness of a quasi steady analysis was undertaken. Using a fuel off simulation of the scramjet duct with the transient inflow properties from the X2 facility nozzle exit, the convective terms for pressure were shown to be two orders of magnitude larger than local terms indicating the dominance of the convective terms change in flow properties at any location allowing quasi-steady flow to be assumed. A normalisation procedure was developed to deal with the transient nature of the data and to accurately represent the axial progression of the gas through the duct. The numerical simulations were also used to show that both flow establishment was achieved and that impulsive starting of the intake would occur. Experimentation with the scramjet using static pressure measurements throughout the body side of the engine provided verification of supersonic combustion. This was verified by the doubling of the static pressure from the start to the end of the combustor for an air test gas, whereas with a nitrogen test gas no significant change in pressure occurred. Effects of fuel equivalence ratio, injector size and cowl position were also investigated. A net inviscid thrust was predicted, using the quasi-steady flow analysis, indicating a specific impulse of 183 s. This work provides evidence to validate the use of expansion tube facilities for experimental testing of scramjets at flight duplication conditions. Limitations due to boundary layer transition flow effects has been shown to be avoidable. Numerical simulations of the facilities showed good agreement with experimental measurements, allowing definition of freestream properties and can now be applied to further scramjet conditions with confidence. Stable, supersonic combustion was shown to be produced for these expansion tube conditions. Coupling the transient simulation of the flow condition with a numerical calculation of the fuel off experimental scramjet has been useful in both verification of the design and performance predictions. Appropriate techniques have been presented to analyse scramjet pressure and thrust measurements where transient effects are present in the freestream.

Thesis (M.A.)--University of Texas at Dallas, 2007. / Includes vita. Includes bibliographical references (leaves 67-75)