Le sujet de cette thèse est l'inférence statistique de processus d'Ornstein-Uhlenbeck multi-dimensionnels. Dans une première partie, nous introduisons un modèle de graphes stochastiques définis comme observations binaires de trajectoires. Nous montrons alors qu'il est possible de déduire la dynamique de la trajectoire sous-jacente à partir des observations binaires. Pour ceci, nous construisons des statistiques à partir du graphe et montrons de nouvelles propriétés de convergence dans le cadre d'une observation en temps long et en haute fréquence. Nous analysons aussi les propriétés des graphes stochastiques du point de vue des réseaux évolutifs. Dans une deuxième partie, nous travaillons sous l'hypothèse d'information complète et en temps continu et ajoutons une hypothèse de sparsité concernant le paramètre de textit{drift} du processus d'Ornstein-Uhlenbeck. Nous montrons alors des propriétés d'oracle pointues de l'estimateur Lasso, prouvons une borne inférieure sur l'erreur d'estimation au sens minimax et démontrons des propriétés d'optimalité asymptotique de l'estimateur Lasso Adaptatif. Nous appliquons ensuite ces méthodes pour estimer la vitesse de retour à la moyenne des retours journaliers d'actions américaines ainsi que des prix de futures de dividendes pour l'indice EURO STOXX 50. / The subject if this thesis is the statistical inference of multi-dimensional Ornstein-Uhlenbeck processes. In a first part, we introduce a model of stochastic graphs, defined as binary observations of a trajectory. We show then that it is possible to retrieve the dynamic of the underlying trajectory from the binary observations. For this, we build statistics of the stochastic graph and prove new results on their convergence in the long-time, high-frequency setting. We also analyse the properties of the stochastic graph from the point of view of evolving networks. In a second part, we work in the setting of complete information and continuous time. We add then a sparsity assumption applied to the drift matrix coefficient of the Ornstein-Uhlenbeck process. We prove sharp oracle inequalities for the Lasso estimator, construct a lower bound on the estimation error for sparse estimators and show optimality properties of the Adaptive Lasso estimator. Then, we apply the methods to estimate mean-return properties of real-world financial datasets: daily returns of SP500 components and EURO STOXX 50 Dividend Future prices.

No description available.

No / It is challenging to use traditional data mining techniques to deal with real-time data stream classifications. Existing mining classifiers need to be updated frequently to adapt to the changes in data streams. To address this issue, in this paper we propose an adaptive ensemble approach for classification and novel class detection in concept drifting data streams. The proposed approach uses traditional mining classifiers and updates the ensemble model automatically so that it represents the most recent concepts in data streams. For novel class detection we consider the idea that data points belonging to the same class should be closer to each other and should be far apart from the data points belonging to other classes. If a data point is well separated from the existing data clusters, it is identified as a novel class instance. We tested the performance of this proposed stream classification model against that of existing mining algorithms using real benchmark datasets from UCI (University of California, Irvine) machine learning repository. The experimental results prove that our approach shows great flexibility and robustness in novel class detection in concept drifting and outperforms traditional classification models in challenging real-life data stream applications. (C) 2013 Elsevier Ltd. All rights reserved.

My original contribution to theory and practice formulates management consultancy as a social act evolving within interaction with clients whereby identity, as an emerging process, can form and be formed within consultant-client relationships. Drawing on Stacey's work on complex responsive process thinking, I have described a reflexive, social self, highlighting the implications for management consultants of this open-ended responsiveness of identity formation. Within the prevailing management literature there is a sense that consultants design interventions that change organisations, whether through working on leadership development, executive coaching, providing expertise or facilitating organisational change. As part of my original contribution I pick up on the emotional, relational and occasionally messy nature of consulting, which is frequently overlooked in the literature. My research into the emergence of intentions and the formation of identity within consultant-client relationships analyses my work as a researcher-practitioner working within large financial service organisations through a variety of consulting projects. The inquiry examines my professional practice, researched through a social, iterative and temporal method centring on reflexive, narrative inquiries. I illuminate the fundamental conversational nature of consultant-client relationships; challenging the view of consulting as a transaction whereby the consultant provides a service, withdrawing relatively unchanged. I postulate consulting as a series of conversations with interdependent people wherein emerging themes organise new ways of relating and novelty evolves. Drawing on Elias' process sociology I extrapolate the fundamental interdependence of consultant-client relationships; conceptualising management consulting from a complex responsive processes way of relating. I challenge the notion of intention as located in the individual; an independent, disembodied, thought before action predicated on an 'if-then' notion of causality, underpinned by an assumption of human beings as autonomous and rational. I develop the work of Joas arguing that intentions are emerging, social and embodied; a theme organising conversations. In particular I detail how strong emotions and embodiment occur in those arresting moments, where experiences of inclusion and exclusion, can alert the consultant to new ways of relating. My inquiry has highlighted the significance for management consultants of realising the fundamentally social nature of human interaction and the importance of responsiveness in the living present. With reference to Mead's view of conversation as a pattern of gesture/ response I highlight the consultant-client relationship as co-created and therefore not to be ordered by the consultant who can, nevertheless, pick up on and influence new patterns of relating as they evolve.

Le Virus de l’Hépatite C (VHC) infecte 170 millions de personnes dans le monde mais aucun vaccin n’est encore disponible. Le processus d’entrée du VHC dans les hépatocytes représente une cible prometteuse pour le développement de stratégie thérapeutique et est finement régulé par un nombre par les deux glycoprotéines d’envelope du VHC, E1 et E2, assemblé sous la forme d’un hétérodimère incorporé à la surface des particules virales. Cependant, comment E1 et E2 dialoguent, modifient leurs conformations et se coordonnent mutuellement au cours de l’entrée reste encore à être définit. Dans ce travail, nous avons souhaité clarifier l’interrelation entre E1 and E2 au cours de l’entrée afin d’ouvrir la voie à de potentiels stratégies thérapeutiques. Nous avons tout d’abord examiné si une importante divergence génétique entre des hétérodimères E1E2 pouvait être liée à l’existence de fonctions particulières. Nous avons observé une spécialisation des E1E2 isolé des Lymphocytes B pour l’infection de ces mêmes cellules mais pas des hépatocytes, suggérant que de nouvelles fonctions peuvent émerger de la plasticité conformationel de E1E2. Dans un second temps, nous sommes parvenus à identifier un dialogue conservé entre E1 et le domaine III de E2 (E2 DIII), critique pour les processus d’attachement et de fusion du VHC. Nous avons aussi montré grâce à une approche bio-informatique l’existence d’une co-évolution très importante entre E1 et E2. Cette approche a également prédit de potentiel changement de conformations au sein de l’hétérodimère, suggérant que E2 est sans doute une protéine de fusion capable de se replier sur elle-même via le repliement de son domaine III et l’aide de E1. Ainsi, ces différents travaux soulignent l’implication de E1 et E2 au sein de dialogues fins et complexes, qui régulent à la fois les conformations et les fonctions de l’hétérodimère. Ainsi, cela suggère que l’hétérodimère E1E2 représente plutôt une unité fonctionnelle et structurale unique, plutôt que l’association de deux protéines aux fonctions distinctes. / Hepatitis C Virus (HCV) infects more than 170 million people worldwide but no vaccine is available yet. HCV entry may represent a promising target for therapies and is mediated by two envelope glycoproteins, E1 and E2, assembled as heterodimer onto the virus surface. However, how E1 and E2 dialog, structurally rearrange and act together during these steps remain poorly defined. In this work, we aimed to clarify the interrelation of E1E2 during virus entry, thus opening ways to potential new therapeutic strategies. We first investigated whether a strong genetic divergence between E1E2 heterodimers may highlight distinct functions. We observed that B-cell derived E1E2 were specialized for B-cell infection, suggesting that new functions can emerge from the E1E2 conformational plasticity. In a second approach, we identified a conserved dialog between E1 and the domain III of E2 that was critical for virus binding and fusion. Moreover, a computational model predicted a strong co-evolution between E1 and E2 as well as potential structural rearrangements, suggesting that HCV E2 is likely a fusion protein able to fold over via its domain III through the mediation of E1. Altogether, these different works highlight that E1 and E2 are involved in complex dialogs that regulate the heterodimer folding and functions, suggesting that E1E2 heterodimer is more likely a single functional protein entity than an association of two proteins with specific functions.

Os direitos sociais são fruto das lutas dos indivíduos por melhores condições de trabalho e de vida ao longo dos séculos XVIII e XIX, embora os direitos mínimos dos trabalhadores somente tenham sido sistematicamente inseridos nas Constituições e albergados pelos diplomas internacionais ao no decorrer do século XX. No Brasil, os direitos fundamentais do trabalhador foram elencados na Constituição Federal de 1934 e, a partir de então, foram sendo ampliados até a Constituição Federal de 1988, nomeada de cidadã, que inaugurou um marco na constitucionalização desses direitos sociais, integrando-os efetivamente ao rol dos direitos fundamentais, conferindo-lhes aplicabilidade imediata e natureza de cláusulas pétreas. Toda essa sistemática traçada pelo legislador constituinte exige que os aplicadores do Direito tratem esses direitos trabalhistas como realmente fundamentais, inclusive no que tange às questões relativas à eficácia jurídica, efetividade e aplicabilidade. Ao lado do dilema da falta de efetividade das normas que estabelecem esses direitos, pela cultura de seu descumprimento reiterado pelos empregadores, existe outro problema igualmente grave: a ausência de implementação ou a implementação restritiva de vários direitos fundamentais trabalhistas, tanto pela ausência de leis infraconstitucionais que regulamentem as normas que os estatuem, quanto pela interpretação jurisdicional que lhes é conferida. Embora com alguns avanços no campo hermenêutico, a atuação do Poder Judiciário ainda tem sido insuficiente para a implementação plena dos direitos fundamentais sociais, tanto em virtude das resistências externas a uma postura mais ativa do Judiciário, quanto pela tendência de auto-restrição dos juízes em se aceitarem como órgãos legítimos para concretizar os direitos sociais esculpidos na Constituição. Ambos os problemas têm fulcro em uma concepção teórica restritiva de cidadania e, consequentemente, do exercício efetivo dos direitos fundamentais sociais pelos seus titulares, e em uma leitura desatualizada da teoria da separação dos poderes de Montesquieu, que desconsidera o Poder Judiciário como destinatário das normas de direitos fundamentais sociais. Sem embargo, a Constituição de 1988 adotou uma concepção de cidadania ampla, que pode ser denominada de cidadania social, pois o cidadão tem não apenas a prerrogativa de exercer os seus direitos políticos e civis, como também os seus direitos sociais, além de poder requerer ao Judiciário a implementação dos direitos cujo exercício se encontra limitado, inclusive pela interpretação involutiva dos dispositivos constitucionais, totalmente desvinculada da realidade social. O cidadão tem garantido constitucionalmente o acesso a uma ordem jurídica justa, no sentido do acesso aos tribunais, do exercício do direito de ação, com todas as garantias concernentes ao devido processo legal, e de uma prestação jurisdicional adequada e em tempo razoável que concretize os direitos reconhecidos em juízo. Para isso, o juiz deve se valer não apenas da utilização de mecanismos processuais adequados, mas também, em se tratando de pleitos que envolvam direitos fundamentais, da interpretação evolutiva, isto é, da atribuição de novos conteúdos à norma constitucional, sem a alteração do texto do dispositivo constitucional, em virtude de mudanças sócio-econômico-políticas não previstas pelo constituinte. Embora existam exemplos de decisões, majoritárias ou pontuais proferidas por juízes ou pelos Tribunais do Trabalho, em que se vislumbra a interpretação constitucional evolutiva de alguns direitos fundamentais trabalhistas, para a implementação plena desses direitos a atuação desse ramo especializado do Judiciário deve ser mais incisiva e abrangente. Dessa forma, o intento da presente tese é demonstrar que, para garantir a implementação efetiva de vários direitos dos trabalhadores estabelecidos nos artigos 7º a 11 da CF/88 e artigo 10 do ADCT, a Justiça do Trabalho deverá adotar uma hermenêutica jurisdicional pautada na interpretação evolutiva das normas constitucionais e na concepção ampliativa do exercício dos direitos fundamentais, fundada no princípio da cidadania social. / Social rights are the result of individuals\' struggles for better working and living conditions in the eighteenth and nineteenth centuries, although the basic rights of workers have only been systematically inserted in the Constitution and encompassed by international treaties, covenants and declarations in the twentieth century. In Brazil, the fundamental rights of workers were listed in the Constitution of 1934 and, thereafter, have been extended to the Federal Constitution of 1988, referred to as \"citizen\", which represented a milestone for the constitutionalization of social rights, integrating them effectively to the role of fundamental rights and giving them instant applicability and the quality of entrenched clauses. The same procedure drafted by the constitutional legislators requires that lawenforcers see these labor rights as something really fundamental, including subjects related to the legal effectiveness, efficacy and applicability. Next to the dilemma of lack of effectiveness of the rules that determine these rights, that is to say the employers culture of a repeated failure to comply with them, there is another equally serious problem: the lack of implementation or putting into effect, in a restrictive way, various fundamental labor rights, both because of the absence of infraconstitutional laws which regulate the rules that set them up, as well as the judicial interpretation they were given. Despite some advances in the hermeneutic field, the judiciary has still been not enough for the full implementation of fundamental social rights, both because of external opposition to a more active role of the judiciary, and by the self-restraint judges tendency to accept themselves as a right and proper means for achieving the social rights guaranteed by the Brazilian Constitution. Both problems have a restrictive theoretical fulcrum conception of citizenship and, consequently, the effective exercise of fundamental social rights by their holders, and an outdated interpretation of the Montesquieus theory of separation of powers, which disregards the judiciary as a recipient of the fundamental social rights standards. Nevertheless, the Constitution of 1988 adopted a broad conception of citizenship, which can be called \"social\" citizenship since citizens has not only the prerogative of exercising their civil and political rights, but also their social rights, as well as requesting the Judiciary for the implementation of rights which exercise is limited, even because of the involuting interpretation of constitutional provisions, totally divorced from social reality. Citizens have a constitutionally guaranteed access to a fair legal system in the sense of accessing courts, exercising the right of action, with all the guarantees pertaining to a due legal procedure and proper adjudication in a reasonable term that makes available the rights recognized in court. For that, judges must not only rely on the use of appropriate procedural mechanisms, but also, in case of claims involving fundamental rights, on the evolutionary interpretation, that is, assigning new content to the constitutional rules, without changing the text of the constitution because of socio-economic and political changes not foreseen by the constituent. Although there are examples of majoritarian or specific decisions taken by judges or by the Labor Courts, which are able to glimpse the evolving constitutional interpretation of some fundamental labor rights, for the full implementation of these rights, the performance of that specialized branch of the judiciary should be more incisive and comprehensive. Thus, the goal of this thesis is to demonstrate that to ensure the effective implementation of various workers\' rights, as laid down in Articles 7 to 11 and Article 10 of CF/88 ADCT, the Labor Court should adopt judicial hermeneutics guided by the evolving interpretation of constitutional rules and the ampliative conception of exercising fundamental rights, based on the principle of social citizenship.

O comportamento dinâmico das redes sem fio as torna muito peculiares e de difícil análise. No entanto, algumas destas redes, como as de sensores com funcionamento intermitente, redes periódicas ou cíclicas e as do sistema de satélites de órbita baixa têm um comportamento dinâmico relativamente previsível, pois as variações da topologia da rede no tempo são quase que determinísticas. Recentemente, um modelo teórico -- grafos evolutivos -- foi proposto com o intuito de capturar o comportamento dinâmico destas redes e formalizar algoritmos de roteamento de custo mínimo, além de outros. Os algoritmos e idéias obtidos com este modelo são teoricamente muito eficientes, mas, no entanto, antes deste trabalho não existiam estudos do uso destes modelos em situações práticas. Assim, o objetivo deste trabalho é analisar a aplicabilidade da teoria de grafos evolutivos na construção de protocolos de roteamento eficientes em cenários realistas. Foram implementados dois protocolos de roteamento para redes móveis ad hoc baseados nos algoritmos de grafos evolutivos, são eles: Jornada que Chega Mais Cedo e Jornada Mais Curta. Extensivas simulações foram realizadas utilizando o simulador de redes NS2 e os resultados foram comparados com outros quatro protocolos clássicos para este tipo de rede: AODV, DSR, OLSR e DSDV. Os resultados preliminares mostram que este recente modelo tem muito potencial para ser uma ferramenta poderosa no desenvolvimento e análise de algoritmos para redes dinâmicas com comportamento previsível. No entanto, foram apontados alguns aspectos que precisam ser melhores estudados para que estes algoritmos possam ser utilizados em situações reais. / The assessment of routing protocols for wireless networks is a difficult task, because of the networks\' highly dynamic behavior and the absence of benchmarks. However, some of these networks, such as intermittent wireless sensors networks, periodic or cyclic networks, and low earth orbit satellites systems, have more predictable dynamics, as the temporal variations in the network topology are somehow deterministic, which may make them easier to study. Recently, a graph theoretic model -- the evolving graphs -- was proposed to help to capture the dynamic behavior of these networks, in view of the construction of least cost routing and other algorithms. The algorithms and insights obtained through this model are theoretically very efficient and intriguing. However, before this work there was no study on the use of such theoretical results into practical situations. Therefore, the objective of our work is to analyze the applicability of the evolving graph theory in the construction of efficient routing protocols in realistic scenarios. We use the NS2 network simulator to first implement two evolving graph based routing protocols: Foremost Journey and Shortest Journey, They are evaluated and compared to four major ad-hoc protocols: AODV, DSR, OLSR and DSDV. Interestingly, our experiments show that evolving graphs have all the potentials to be an effective and powerful tool in the development and analysis of algorithms for dynamic networks, with predictable dynamics at least. In order to make this model widely applicable, however, some practical issues still have to be addressed and incorporated into the model.

Atualmente, muitas redes com características dinâmicas estão em funcionamento (por exemplo MANETs, DTNs, redes oportunistas, etc). Neste trabalho, estudamos um modelo para estas redes chamado de Grafos Evolutivos, que permite expressar a dinamicidade das conexões entre nós por meio de uma simples extensão da estrutura comum de grafos. Esta modelagem é utilizada no arcabouço proposto por Casteigts et al. para definir algoritmos distribuídos em redes dinâmicas, que utiliza grafos evolutivos para representar a topologia da rede e renomeação de rótulos para expressar a comunicação entre os nós. Utilizamos esta abordagem para estudar o problema da exclusão mútua distribuída em redes dinâmicas e diversos algoritmos propostos para ele, a fim de definir e validar suas condições necessárias e suficientes de conectividade em redes dinâmicas. Além da formalização de algoritmos, o modelo de grafos evolutivos também pode ser utilizado para analisar redes dinâmicas. Rastros de redes dinâmicas reais são amplamente utilizados na literatura para estudos de algoritmos pois estes geram resultados mais realísticos do que redes simuladas com padrões de movimento. A partir dos detalhes de cada conexão entre nós de um destes rastros, é possível construir um grafo evolutivo, do qual se pode extrair dados como jornadas ótimas entre nós, variação da conectividade no tempo, estabilidade, e periodicidade. Com as informações mencionadas, um pesquisador pode observar com maior precisão as características do rastro, o que facilita na escolha da rede mais apropriada para sua necessidade. Além disso, o conhecimento prévio de tais características de uma rede auxilia no estudo do comportamento de algoritmos executados sobre ela e provém uma validação para suposições geralmente feitas pelos pesquisadores. Para fornecer estas informações, desenvolvemos uma ferramenta Web que analisa rastros de redes dinâmicas e agrega os dados em um formato de fácil visualização. Descrevemos, neste trabalho, a implementação e a utilidade de todos os serviços da ferramenta. / Lately, several networks with dynamic properties (for instance MANETs, DTNs, opportunistic networks, etc) are functioning. In this work, we studied a model for these networks called Evolving Graphs, which allows the expression of the dynamicity of the conections between nodes through a simple extension of the common graph structure. This model is used by the framework proposed by Casteigts et al. to define distributed algorithms in dynamic networks, which uses evolving graphs to represent the network topology and graph relabelling to express the communication between nodes. Using this approach, we study the distributed mutual exclusion problem in dynamic networks and several algorithms proposed to solve it, in order to define and validate their necessary and sufficient connectivity conditions. Apart from the formalization of algorithms, the evolving graphs model can also be used to analyze dynamic networks. Dynamic network traces are widely used in the literature in order to study algorithms, as they generate better results than simulated networks with movement patterns. From the details of every connection between nodes in a trace, it is possible to build an evolving graph, from which a large amount of information can be extracted, such as optimal journeys between nodes, variation of the conectivity over time, stability and periodicity. With the aforementioned information, a researcher might observe the characteristics of a trace more precisely, which facilitates the process of choosing the most appropriate trace for his needs. Furthermore, the early knowledge of such characteristics of a network helps in the study of the behavior of the algorithms exected over it and provides a validation for the assumptions usually made by the researchers. In order to provide this information, we developed a web tool which analyzes dynamic network traces and aggregates the data in an easily readable format. In this work, we describe the implementation and usefulness of every service in the tool.

Submitted by Rosivalda Pereira (mrs.pereira@ufma.br) on 2017-09-04T18:35:15Z No. of bitstreams: 1 OrlandoRochaFilho.pdf: 10104010 bytes, checksum: 7c750a6e03597fc2e7f7474b62c35a46 (MD5) / Made available in DSpace on 2017-09-04T18:35:15Z (GMT). No. of bitstreams: 1 OrlandoRochaFilho.pdf: 10104010 bytes, checksum: 7c750a6e03597fc2e7f7474b62c35a46 (MD5) Previous issue date: 2017-04-24 / This thesis presents a maximum likelihood based modeling approach applied to dynamic systems operating in non-stationary environment that uses recursive parametric estimation based on the method of fuzzy instrumental variable. The context is evolving and the idea is to guarantee a robust for estimation of the parameters of noise-corrupted experimental data. The methodology consists of an evolving fuzzy clustering algorithm based on the similarity of the data which employs an adaptive distance norm based on the maximum likelihood criterion that use an adaptive search strategy on the experiment in order to avoid the curse of dimensionality related to the number of rules created during data clustering of the data set. The computational and experimental results to exemplify the proposed methodology are: statistical analysis of the fuzzy instrumental variable inserted in the evolving context; black box modeling of a thermal plant; identification of a benchmark nonlinear system widely published in the literature and the black box modeling of a 2DOF helicopter. These examples are used to illustrate the performance and efficiency by operating in a non–stationary environment. / Nesta tese é apresentada uma proposta de modelagem baseada máxima verossimilhança aplicada a sistemas dinâmicos operando em ambiente não-estacionário que utiliza a estima- ção paramétrica recursiva baseada no método de variável instrumental nebulosa, inserido no contexto evolutivo, no sentido de garantir robustez para estimação dos parâmetros diante de dados experimentais corrompidos por ruído. A metodologia é composta por um algoritmo de agrupamento nebuloso evolutivo baseado na similaridade dos dados que emprega uma norma de distância adaptativa baseada no critério de máxima verossimilhança que utiliza uma estratégia de busca adaptativa no experimento para evitar o problema da maldição de dimensionalidade relacionada ao número de regras criadas durante o agrupamento do conjunto de dados. Os resultados computacionais e experimentais para exemplificação da metodologia proposta são: análise estatística da variável instrumental nebulosa inserida no contexto evolutivo; na modelagem caixa preta de uma planta térmica (processo térmico); identificação de um sistema não-linear amplamente divulgado na literatura e a modelagem caixa preta de um helicóptero com dois graus de liberdade que ilustra o desempenho e a eficiência operando ambiente não-estacionário.

This thesis presents a starburst model for far-infrared/sub-millimeter/millimeter (FIR/sub-mm/mm) line emission of molecular and atomic gas in an evolving starburst region, which is treated as an ensemble of non-interacting hot bubbles which drive spherical shells of swept-up gas into a surrounding uniform gas medium. These bubbles and shells are driven by winds and supernovae within massive star clusters formed during an instantaneous starburst. The underlying stellar radiation from the evolving clusters affects the properties and structure of photodissociation regions (PDRs) in the shells, and hence the spectral energy distributions (SEDs) of the molecular and atomic line emission from these swept-up shells and the associated parent giant molecular clouds (GMCs) contains a signature of the stage evolution of the starburst. The physical and chemical properties of the shells and their structure are computed using a a simple well known similarity solution for the shell expansion, a stellar population synthesis code, and a time-dependent PDR chemistry model. The SEDs for several molecular and atomic lines ($^{12}$CO and its isotope $^{13}$CO, HCN, HCO$^+$, C, O, and C$^+$) are computed using a non-local thermodynamic equilibrium (non-LTE) line radiative transfer model. By comparing our models with the available observed data of nearby infrared bright galaxies, especially M 82, we constrain the models and in the case of M 82, provide estimates for the age of the recent starburst activity. We also derive the total H$_2$ gas mass in the measured regions of the central 1 kpc starburst disk of M 82. In addition, we apply the model to represent various stages of starburst evolution in a well known sample of nearby luminous infrared galaxies (LIRGs). In this way, we interpret the relationship between the degree of molecular excitation and ratio of FIR to CO luminosity to possibly reflect different stages of the evolution of star-forming activity within their nuclear regions. We conclude with an assessment of the strengths and weaknesses of this approach to dating starbursts, and suggest future work for improving the model.