The analysis of longitudinal data has been a popular subject for the recent years. The growth of the Generalized Estimating Equation (GEE) Liang & Zeger, 1986) is one of the most influential recent developments in statistical practice for this practice. GEE methods are attractive both from a theoretical and a practical standpoint. In this paper, we are interested in the influence of different "working" correlation structures for modeling the longitudinal data. Furthermore, we propose a new AIC-like method for the model assessment which generalized AIC from the point of view of the data generating. By comparing the difference of the log-likelihood functions between different correlation models, we define the exact value to create an interval for our model selection. In this thesis, we combine the GEE method and a new generalized AIC Index for the longitudinal data with different correlation structures.

There may be several mechanisms that drive observed interactions between plants and pollinators in an ecosystem, many of which may involve trait matching or trait complementarity. Hence a model of insect species activity on plant species should be represented as a mixture of these linkage rules. Unfortunately, ecologists do not always know how many, or even which, traits are the main contributors to the observed interactions. This thesis proposes the Latent Dirichlet Allocation (LDA) model from artificial intelligence for modelling the observed interactions in an ecosystem as a finite mixture of (latent) interaction groups in which plant and pollinator pairs that share common linkage rules are placed in the same interaction group. Several model selection criteria are explored for estimating how many interaction groups best describe the observed interactions. This thesis also introduces a new model selection score called ``penalized perplexity". The performance of the model selection criteria, and of LDA in general, are evaluated through a comprehensive simulation study that consider networks of various size along with varying levels of nesting and numbers of interaction groups. Results of the simulation study suggest that LDA works well on networks with mild-to-no nesting, but loses accuracy with increased nestedness. Further, the penalized perplexity tended to outperform the other model selection criteria in identifying the correct number of interaction groups used to simulate the data. Finally, LDA was demonstrated on a real network, the results of which provided insights into the functional roles of pollinator species in the study region.

Le travail soumis commence par un aperçu du micro-crédit tel qu'il a été introduit au Bangladesh par M. Yunus. Puis on donne un modèle stochastique des retards de versement. Comme ces retards ne donnent pas lieu à une sanction financière, ils constituent, de fait, une baisse du taux réel de crédit. Ce taux est alors, lui-même, aléatoire. On calcule un taux espéré en fonction de la probabilité de retard de remboursement hebdomadaire. On déduit que ce taux espéré est d'environ 3.5% inférieur au taux (annoncé) du cas déterministe si l'on considère que 3% des retards atteignent 4 semaines. Le travail se poursuit par une étude statistique de données du micro-crédit en Thaïlande. On commence par présenter un modèle de régression logistique du taux de remboursement par rapport aux 23 variables mesurées sur un échantillon de 219 groupes d'emprunteurs. On présente ensuite une sélection des variables les plus pertinentes selon un critère AIC ou BIC par une méthode "backward stepwise". Finalement des expériences sur des sous-échantillons montrent une bonne stabilité du choix des variables obtenues par la sélection.

This research explores factor analysis applied to data from skewed distributions for the general skew model, the selection-elliptical model, the selection-normal model, the skew-elliptical model and the skew-normal model for finite sample sizes. In terms of asymptotics, or large sample sizes, quasi-maximum likelihood methods are broached numerically. The skewed models are formed using selection distribution theory, which is based on Rao’s weighted distribution theory. The models assume the observed variable of the factor model is from a skewed distribution by defining the distribution of the unobserved common factors skewed and the unobserved unique factors symmetric. Numerical examples are provided using maximum likelihood selection skew-normal factor analysis. The numerical examples, such as maximum likelihood parameter estimation with the resolution of the “sign switching” problem and model fitting using likelihood methods, illustrate that the selection skew-normal factor analysis model better fits skew-normal data than does the normal factor analysis model.

本篇論文著重於探討ARMA模型的選模準則，過去較為著名的AIC、BIC等選模準則中，若總參數個數相同，模型選擇便簡化為比較各模型的概似函數在MLE下的值，故本研究將假設檢定定義為檢定總參數個數；截至目前為止，選模準則在使用上以AIC及BIC較為普遍，此兩種選模準則從本研究所定義的假設檢定的觀點來看，AIC犯型一誤差機率高，同時檢定力也高；BIC犯型一誤差的機率極低，同時檢定力也相對不高，本研究從此觀點提出一個選模準則方法，嘗試將上述兩種方法折衷，將型一誤差控制在5%，且檢定力略高於BIC。模擬的結果在理想的情形下皆符合預期，但在真實情形本研究方法涉及第一階段的模型選取，本研究提供兩種第一階段的模型選取方法，模擬的結果顯示，方法一型一誤差略為膨脹，檢定力增幅顯著；方法二型一誤差控制精準，但檢定力表現較差。本研究所提出的方法計算時間較為冗長，但若想將 AIC 及 BIC 方法折衷，可考慮嘗試本研究方法。 / This thesis focuses on model selection criteria for ARMA models. For information-based criteria such as AIC and BIC, the task of model selection is reduced to the comparison among likelihood values at maximum likelihood estimates if the numbers of parameters in candidate models are all the same. Thus the key step in model selection is the determination of the total number of parameters. The determination of number of parameters can be addressed using a hypothesis testing approach, where the null hypothesis is that the total number of model parameters is equal to a given number k and the alternative hypothesis is that the total number of parameters is equal to k+1. In this thesis, an information-based model selection method is proposed, where the number of parameters is determined using a two-stage testing procedure, which is constructed with the attempt to control the average type I error probability to be 5%. When using BIC in the above testing problem, simulation results indicate that the average type I error probability for BIC is lower than 0.05, so it is expected the proposed test is more powerful than BIC. The first stage of the proposed test involves selecting the most likely models under the null and the alternative hypothesis respectively. Two methods are considered for the first-stage selection. For the first method, the type I error probability can be larger than 0.05, but the power is significantly larger than BIC. For the second method, the type I error probability is under control, but its power increment is comparatively low. The computing time for the proposed test is rather long. However, for those who need an eclectic method between AIC and BIC, the proposed test can serve as a reasonable choice.

abstract: This thesis examines the application of statistical signal processing approaches to data arising from surveys intended to measure psychological and sociological phenomena underpinning human social dynamics. The use of signal processing methods for analysis of signals arising from measurement of social, biological, and other non-traditional phenomena has been an important and growing area of signal processing research over the past decade. Here, we explore the application of statistical modeling and signal processing concepts to data obtained from the Global Group Relations Project, specifically to understand and quantify the effects and interactions of social psychological factors related to intergroup conflicts. We use Bayesian networks to specify prospective models of conditional dependence. Bayesian networks are determined between social psychological factors and conflict variables, and modeled by directed acyclic graphs, while the significant interactions are modeled as conditional probabilities. Since the data are sparse and multi-dimensional, we regress Gaussian mixture models (GMMs) against the data to estimate the conditional probabilities of interest. The parameters of GMMs are estimated using the expectation-maximization (EM) algorithm. However, the EM algorithm may suffer from over-fitting problem due to the high dimensionality and limited observations entailed in this data set. Therefore, the Akaike information criterion (AIC) and the Bayesian information criterion (BIC) are used for GMM order estimation. To assist intuitive understanding of the interactions of social variables and the intergroup conflicts, we introduce a color-based visualization scheme. In this scheme, the intensities of colors are proportional to the conditional probabilities observed. / Dissertation/Thesis / M.S. Electrical Engineering 2012

Ce mémoire de thèse de doctorat présente l'évaluation d'un système de réalité mixte dans le cadre d'une utilisation sur le site d'opération de construction. Il s'agit notamment de déterminer la pertinence d'un tel outil mobile pour des opérateurs pour les assister dans leurs tâches quotidiennes, et notamment dans la préparation et le suivi des opérations de construction ou rénovation. Cet outil se voudrait être un outil d'aide à la décision pour les maîtres d'ouvrages et maîtres d'œuvre. Le cas d'étude porte sur la rénovation virtuelle des baies anciennes (datées du XVIIIème siècle) dans une cellule des bâtiments conventuels de Cluny (Saône et Loire, France). L'approche consiste à comparer l'efficacité, la précision et la rapidité d'opérateurs dans la réalisation de tâches identiques. Trois méthodes liées à l'utilisation des nouvelles technologies dans le domaine de l'AIC (Architecture Ingénierie et Construction) sont comparées, elles ont guidé la définition du protocole expérimental. La première méthode traditionnelle fournit à l'opérateur de la documentation papier. La seconde met en œuvre la dématérialisation des données constructives, accessibles depuis un ordinateur de bureau. La troisième méthode plus innovante ajoute à la précédente l'accès colocalisé à la base de données grâce à un terminal mobile. Une étude qui a suivi a porté sur la visualisation et l'interprétation de résultats de simulation thermique, en réalité virtuelle. La comparaison des trois premières méthodes a donné lieu à une première expérimentation dont les résultats ont montré la légère prédominance du second scénario (travail sur ordinateur de bureau). Cependant, au-delà des aspects d'ergonomie et d'interface utilisateur, des investigations complémentaires doivent être menées pour étudier l'opportunité du développement du BIM in situ, c'est-à-dire l'utilisation du modèle de données du bâtiment (BIM- Building Information Model) sur le chantier. / This dissertation presents the evaluation of an onsite augmented reality tool and its relevance for helping construction agents to prepare and monitor the progress of a building's construction or renovation through a mobile device. The case study focuses on virtual renovation works regarding an ancient window –dated eighteenth century- in a room of the Cluny (Saone et Loire, France) abbey buildings. The study aims at comparing the efficiency and the precision of users' behavior in four situations while performing identical sets of tasks. Three methods related to the ICT uses of onsite AEC (Architecture, Engineering and Construction) guided the experiment: the first method focuses on paper-based content; the second method provides a digital model of the project on a workstation. The third method consists in using a full digital model with colocation access to the database on a mobile device. The fourth method considers working in an immersive room to interpret thermal simulation data. The result of this work is dedicated mainly as a decision-aid tool for project owners and constructors. The comparison between these methods led to a first experiment whose results favor the second method, which implies working on a desktop workstation. However, beyond the aspect of ergonomics and user interface, further investigations are necessary to study the propriety of using the Building Information Model (BIM) on the construction site.

Pharmacometrics is widely used in drug development. Models are developed to describe pharmacological measurements with data gathered from a clinical trial. The information can then be applied to, for instance, safely establish dose-response relationships of a substance. Glycated hemoglobin (HbA1c) is a common biomarker used by models within antihyperglycemic drug development, as it reflects the average plasma glucose level over the previous 8-12 weeks. There are five different nonlinear mixed-effects models that describes HbA1c-formation. They use different biomarkers such as mean plasma glucose (MPG), fasting plasma glucose (FPG), fasting plasma insulin (FPI) or a combination of those. The aim of this study was to compare their performances on a population and an individual level using model averaging (MA) and to explore if reduced trial durations and different treatment could affect the outcome. Multiple weighting methods were applied to the MA workflow, such as the Akaike information criterion (AIC), cross-validation (CV) and a bootstrap model averaging method. Results show that in general, models that use MPG to describe HbA1c-formation on a population level could potentially outperform models using other biomarkers, however, models have shown similar performance on individual level. Further studies on the relationship between biomarkers and model performances must be conducted, since it could potentially lay the ground for better individual HbA1c-predictions. It can then be applied in antihyperglycemic drug development and to possibly reduce sample sizes in a clinical trial. With this project, we have illustrated how to perform MA on the aforementioned models, using different biomarkers as well as the difference between model weights on a population and individual level.

The history of African Independent Churches (AICs) in Southern Africa goes back for more than a hundred years. They have proliferated geographically and demographically in Africa more than the mainline churches could ever have imagined. They have grown to be as widespread and as influential as the African mainline churches. The reason for this growth is that the AICs are the churches of African indigenous people. They are launched by Africans from a background of an African traditional and cultural frame of reference. The most significant reason is that the founders of these churches are not Westerners, but Africans. Western missionaries find it difficult to understand the AICs from their perspective. Thus the Western churches describe the AICs as sectarian, separatist, syncretist, nativitist, and so on. Nevertheless, some scholars are attempting to view the AICs in positive ways. The fact that these two different churches have never acknowledged each other as true churches is a big challenge for Christian missions in Namibia. Each group has been viewing and judging the other party through suspicious eyes from their own perspective, each driving the other to block the channel of reconciliation before the presence of God. With the aim of solving this problem, this thesis attempts to answer the following questions about the AICs in Namibia: • What are the reasons that the AICs in Namibia have been seceded from mission churches? • What are the activities in civil society in which the AICs in Namibia are currently involved? • Do the AICs engage in any activities which go against the Word of God? • What causes other churches to be suspicious of the AICs? • What level of enculturation is inherent to the AICs in Namibia? In other words, what is the relationship between the liturgies of the AIC and African traditional religion and African culture? • What makes the AICs in Namibia regard themselves as a church? Would it be possible for the AICs and the mainline churches in Namibia to cooperate in Christian missionary work? • What is a possible Korean missionary perspective on this particular situation? This will be dealt throughout this thesis from a Korean missionary missional perspective. / Thesis (PhD)--University of Pretoria, 2014. / tm2015 / Science of Religion and Missiology / PhD / Unrestricted

This study shows the importance of leading toward missional change within BUSA in post-1994 contexts incorporating global, afro-centric missional perspectives as South African Baptists. As my research will indicate, BUSA is at a crucial junction, and I contend that BUSA’s main problem is primarily a missiological problem, with ecclesiastical challenges that urgently need to be addressed by BUSA’s leaders. The importance of BUSA’s critical self- reflection and analysis is paramount. Does BUSA and her mission have a future, or will it fade into obscurity? Utilizing the South African Baptist faith heritage as an important interlocutor with a view to retrospective and prospective Baptist ecclesiology in post- 1994 South African society. Special recognition is given to the contribution of emerging Afro-centric missional voices within the current South African/African context. In doing so, this study seeks to be leadership-oriented, biblically-based and Afro-centric in its approach to missional change with South African Baptist Union churches. Toward missional leadership within BUSA churches this study: <ul> <li>1. Uncovers the importance of an Afro-centric missional ecclesiology, taking into consideration both local and global trends and conversations.</li> <li>2. Uncover a retrospective view of Baptist Ecclesiology within the Southern African context, with its relevance to the history and present-day context of ministry within BUSA.</li> <li>3. Analyses existing statistical data found within the Baptist Annual Handbook, to establish denominational trends since 1994, with a view to identifying significant ministry trends operable within BUSA.</li> 4. Collects, analyses and interprets data from a number of churches from within the Baptist Union of Southern Africa that stand out as significant in three or more ‘missional indicators’ in the first tier of research and analysis. In reading through the pages to follow, you will journey alongside the researcher in:</li> </ul> <ul> <li> Analysing and interpreting the history of Baptists in South Africa with reference to BUSA, BCSA, SABMS and the ABK through a ‘missional lens’</li>. <li> Critically examining current trends visible within BUSA churches since 1994 to the present-day.</li> <li> Undertaking qualitative research to identify phenomenology of people’s shared experience in BUSA</li> <li> Interpreting and objectifying statistical results drawn from qualitative research at local church level; making further recommendations towards an Afro-centric missional ecclesiology relevant to BUSA churches in post-1994 contexts.</li> </ul> / Thesis (PhD)--University of Pretoria, 2012. / Science of Religion and Missiology / unrestricted