This master’s thesis deals with architecture of the IMS network and analysis of the affects when loading the network. Architecture of IMS is a network of new generation. It convergates fixed and mobile networks and it enables quick installation of new multimedia services. The first chapter is focused on the description of the IMS architecture, its components and their function. The next chapter is devoted to the main protocols in the IMS system. It is mainly about signalization protocol SIP. The third chapter focuses on the queueing theory. For simulation of the IMS network, Open IMS Core enviroment was chosen, described in the fourth chapter. Next chapter is dedicated to the IMS Bench SIPp tool used for generating and testing the SIP protocol with focus on the IMS. The final chapter dedicates to the realization of an IMS network. The begining of this chapter deals with the description of individual conections generated by the IMS Bench SIPp tool. In the next part load tests focused on the created IMS network are created and analyzed in detail. The end of the chapter describes the implementation of the real finished call between devices and the Android operating system.

Mount Cameroon is considered the only active volcano along a 1600 km long chain of volcanic complexes called the Cameroon Volcanic Line (CVL). It has erupted seven times during the last 100 years, the most recent was in May 2000. The approximately 500,000 inhabitants that live and work around the fertile flanks are exposed to impending threats from volcanic eruptions and earthquakes. In this thesis, a hazard assessment study that involves both statistical modelling of seismic hazard parameters and the evaluation of a future volcanic risk was undertaken on Mount Cameroon. The Gutenberg-Richter magnitude-frequency relations, the annual activity rate, the maximum magnitude, the rate of volcanic eruptions and risks assessment were examined. The seismic hazard parameters were estimated using the Maximum Likelihood Method on the basis of a procedure which combines seismic data containing incomplete files of large historical events with complete files of short periods of observations. A homogenous Poisson distribution model was applied to previous recorded volcanic eruptions of Mount Cameroon to determine the frequency of eruption and assess the probability of a future eruption. Frequency-magnitude plots indicated that Gutenberg-Richter b-values are partially dependent on the maximum regional magnitude and the method used in their calculation. b-values showed temporal and spatial variation with an average value of 1.53 ± 0.02. The intrusion of a magma body generating the occurrence of relatively small earthquakes as observed in our instrumental catalogue, could be responsible for this high anomalous b-value. An epicentre map of locally recorded earthquakes revealed that the southeastern zone is the most seismically active part of the volcano. The annual mean activity rate of the seismicity strongly depends on the time span of the seismic catalogue and results showed that on average, one earthquake event occurs every 10 days. The maximum regional magnitude values which had been determined from various approaches overlap when their standard deviations are taken into account. However, the magnitude distribution model of the Mt. Cameroon earthquakes might not follow the form of the Gutenberg-Richter frequency magnitude relationship. The datations of the last eruptive events that have occurred on Mt. Cameroon volcanic complex are presented. No specific pattern was observed on the frequency of eruptions, which means that a homogenous Poisson distribution provides a suitable model to estimate the rate of occurrence of volcanic eruptions and evaluate the risk of a future eruption. Two different approaches were used to estimate the mean eruption rate (λ) and both yielded a value of 0.074. The results showed that eruptions take place on average once every 13 years and, with the last eruption occurring over 15 years ago, it is considered that there is at present a high risk of an eruption to occur. / Dissertation (MSc)--University of Pretoria, 2016. / Geology / MSc / Unrestricted

Thèse numérisée par la Direction des bibliothèques de l'Université de Montréal.

Vehicular communication is the enabling technology for the development of the intelligent transportation systems (ITS), which aims to improve the efficiency and safety of transportation. It can be used for a variety of useful applications such as adaptive traffic control, coordinated braking, emergency messaging, peer-to-peer networking for infotainment services and automatic toll collection etc... Accurate yet simple models for vehicular networks are required in order to understand and optimize their operation. For reliable communication between vehicles, the spectrum access is coordinated via carrier sense multiple access (CSMA) protocol. Existing models either use a simplified network abstraction and access control scheme for analysis or depend on simulation studies. Therefore it is important to develop an analytical model for CSMA coordinated communication between vehicles. In the first part of the thesis, stochastic geometry is exploited to develop a modeling framework for CSMA coordinated inter-vehicle communication (IVC) in a multi-lane highway scenario. The performance of IVC is studied in multi-lane highways taking into account the inter-lane separations and the number of traffic lanes and it is shown that for wide multi-lane highways, the line abstraction model that is widely used in literature loses accuracy and hence the analysis is not reliable. Since the analysis of CSMA in the vehicular setting makes the analysis intractable, an aggressive interference approximation and a conservative interference approximation is proposed for the probability of transmission success. These approximations are tight in the low traffic and high traffic densities respectively. In the subsequent part of the thesis, the developed model is extended to multi-hop IVC because several vehicular applications require going beyond the local communication and efficiently disseminate information across the roads via multi-hops. Two well-known greedy packet forwarding schemes are studied, that impose different tradeoffs between per-hop transmission success probability and forward packet progress, namely, the most forward with fixed radius (MFR) and the nearest with forward progress (NFP). In particular, a tractable and accurate modeling framework is developed to characterize the per-hop transmission success probability and the average forward progress for vehicular networks in a multi-lane highway setup. The developed model reveals the interplay between the spectrum sensing threshold of the CSMA protocol and the packet forwarding scheme. A new performance metric is defined, denoted as the aggregate packet progress (APP), which is a dimensionless quantity that captures the tradeoffs between the spatial frequency reuses efficiency, the per-hop transmission success probability, and the per-hop forward progress of the packets. To this end, in contrary to existing studies, the results show that with the proper manipulation of CSMA threshold, the MFR achieves the highest APP.

Compartmentalization is a general principle in biological systems which is observable on all size scales, ranging from organelles inside of cells, cells in histology, and up to the level of groups, herds, swarms, meta-populations, and populations. Compartmental models are often used to model such phenomena, but such models can be both highly nonlinear and difficult to work with. Fortunately, there are many significant biological systems that are amenable to linear compartmental models which are often more mathematically accessible. Moreover, the biology and mathematics is often so intertwined in such models that one can be used to better understand the other. Indeed, as we demonstrate in this paper, linear compartmental models of migratory dynamics can be used as an exciting and interactive means of introducing sophisticated mathematics, and conversely, the associated mathematics can be used to demonstrate important biological properties not only of seasonal migrations but also of compartmental models in general. We have found this approach to be of great value in introducing derivatives, integrals, and the fundamental theorem of calculus. Additionally, these models are appropriate as applications in a differential equations course, and they can also be used to illustrate important ideas in probability and statistics, such as the Poisson distribution.

This dissertation studies the thermodynamic and structural properties of aqueous dispersions of ionic microgels ? soft colloidal particles composed of cross-linked polymer gels that swell in a good solvent. Starting from a coarse-grained model of microgel particles, we perform computer simulations and theoretical calculations using two complementary implementations of Poisson- Boltzmann (PB) theory. Within the framework of a cell model, the nonlinear PB equation is exactly solved and used to compute counterion distributions and osmotic pressures. By varying the free energy with respect to microgel size, we obtain exact statistical mechanical relations for the electrostatic component of the single-particle osmotic pressure. Explicit results are presented for equilibrium swelling ratios of charged microcapsules and of charged cylindrical and spherical microgels with fixed charge uniformly distributed over the surface or volume of the particle. Molecular dynamics simulations validate the theoretical findings. In the second method, within a one-component model framework, based on a linear-response approximation for effective electro- static interactions, we develop Monte Carlo (MC) simulations to compute the equilibrium swelling ratio, bulk osmotic pressure, radial distribution function, and static structure factor. Results presented in this dissertation demonstrate that swelling of ionic microgels increases with increasing microgel charge and decreases with increasing concentration of salt and microgels. In addition, results demonstrate that the microion distributions and osmotic pressure determine equilibrium swelling of microgels. Cell model predictions for bulk osmotic pressure agree well with data from MC simulations of the one-component model. The MC simulations also provide access to structural properties and to swelling behavior of microgels in highly concentrated suspensions. Taken together, results obtained in this work provide insight into factors of importance for practical use of microgels as drug delivery systems, in tissue engineering, and for other biomedical applications.

The purpose of this thesis was to compare two estimation procedures, the method of least squares and the method of maximum likelihood, on sample data obtained from a Poisson distribution. Point estimates of the slope and intercept of the regression line and point estimates of the mean squared error for both the slope and intercept were obtained. It is shown that least squares, the preferred method due to its simplicity, does yield results as good as maximum likelihood. Also, confidence intervals were computed by Monte Carlo techniques and then were tested for accuracy. For the method of least squares, confidence bands for the regression line were computed under two different assumptions concerning the variance. It is shown that the assumption of constant variance produces false confidence bands. However, the assumption of the variance equal to the mean yielded accurate results.

Cette thèse est basée sur deux projets principaux: (1) l'étude de la réponse innée antivirale du poisson zèbre, en particulier des voies de signalisation des interférons de type I et (2) l'étude de leucocytes particuliers localisés au voisinage des neuromastes, structures permettant au poisson de percevoir le flux d'eau qu'il traverse et constituant potentiellement des brèches dans la peau de l'animal. La voie des IFN de type I est le principal composant de l'immunité antivirale innée. Dans cette thèse, deux types de protéines de poisson-zèbre capables d'augmenter l'induction des IFN de type I ont été étudiés. Nous avons montré que les deux orthologues chez le poisson zèbre du facteur de transcription à domaine BTB/POZ nommé PLZF (Promyelocytic leukemia zinc finger) augmentent l'induction de l'Ifn par différents stimuli. Ce travail montre que l'implication de PLZF dans la régulation de la voie IFN est ancienne et peut intervenir à différents niveaux de la voie Ifn. Le second modèle étudié est le gène Ftr83 (finTRIM83), qui appartient à un groupe de TRIM très diversifié et spécifique des poissons. L'expression de cette protéine TRIM induit une très forte induction des Ifn de type I et une protection contre différents virus, via la surexpression de différents ISGs. Ftr83 est exprimé dans la peau et dans les branchies, régions très exposées aux pathogènes, et son niveau d'expression est fortement corrélé au niveau d'expression de l'Ifn. Dans cette thèse, une lignée transgénique où les cellules spécifiquement fluorescentes évoquent des leucocytes localisés à proximité des neuromastes a été étudiée. Ces cellules ont été observées, leurs mouvements suivis et leur transcriptome analysé par séquençage profond après tri au FACS. Cette analyse a identifié des marqueurs typiques de cellules myéloides (macrophages, dendritiques); ces observations sont cohérentes avec l'idée de cellules sentinelles autour des neuromastes. / This thesis is based on the studies of two aspects of innate immunity in zebrafish: 1) proteins involved in the regulation of type I interferon (Ifn) and 2) specialized myeloid cells that patrol neuromasts – mechano-sensory organs embed in the skin that could be pathogen entry sites. In this thesis two different proteins are described for the capability to enhance Ifn production. In one part, two zebrafish orthologues of mammalian transcription factor PLZF (Promyelocytic leukemia zinc finger) are shown to augment type I Ifn and ISG in response to double-stranded RNA viruses. PLZF is a BTB/POZ transcription factor that was recently shown to induce a subset of ISG, in human and mouse. Thus, zebrafish Plzf proteins can operate at multiple steps in the Ifn system. Furthermore, their activity was not dependent on the presence of BTB-domain implying that the underlying mechanism is different from the usual mode of action of BTB/POZ transcription factors. In the second part, fish-specific TRIM ubiquitin ligase - Ftr83 (Fish novel tripartite motif protein 83), mounted a strong anti-viral protection through the upregulation of Ifn. Interestingly a strong correlation between the expression of Ftr83 and Ifn was seen in the gills suggesting that Ftr83 might maintain a low basal level of Ifn signalling in organs constantly exposed to pathogens. In the second part, a GFP reporter transgenic line called medaktin:EGFP has been characterized. It marks leukocytes in the skin surrounding neuromasts. Deep sequencing revealed that these cells express several macrophage and dendritic cell markers, including genes involved in autophagy, microbicidial functions and antigen presentation, thus highlighting them as possible sentinel cells.

Indiana University-Purdue University Indianapolis (IUPUI) / The two-part model (2PM) is the most widely applied modeling and estimation framework in empirical health economics. By design, the two-part model allows the process governing observation at zero to systematically differ from that which determines non-zero observations. The former is commonly referred to as the extensive margin (EM) and the latter is called the intensive margin (IM). The analytic focus of my dissertation is on the development of a general framework for specifying, estimating and drawing inference regarding causally interpretable (CI) effect parameters in the 2PM context. Our proposed fully parametric 2PM (FP2PM) framework comprises very flexible versions of the EM and IM for both continuous and count-valued outcome models and encompasses all implementations of the 2PM found in the literature. Because our modeling approach is potential outcomes (PO) based, it provides a context for clear definition of targeted counterfactual CI parameters of interest. This PO basis also provides a context for identifying the conditions under which such parameters can be consistently estimated using the observable data (via the appropriately specified data generating process). These conditions also ensure that the estimation results are CI. There is substantial literature on statistical testing for model selection in the 2PM context, yet there has been virtually no attention paid to testing the “one-part” null hypothesis. Within our general modeling and estimation framework, we devise a relatively simple test of that null for both continuous and count-valued outcomes. We illustrate our proposed model, method and testing protocol in the context of estimating price effects on the demand for alcohol.

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