This dissertation collects essays that focuses on two branches of the economic literature on imperfect competition: the one of IO on the decision of firms' location and the one of economic growth on market structure and technological progress. Chapter 2 deals with the issue of firms' location and proposes a model that sheds light on how the geographic distribution of firms is affected by strategic interaction in presence of vertically differentiated products. The remaining Chapters, instead, have a common root; they, in fact, deal with the link existing between market structure and growth. More precisely, Chapter 3 studies how knowledge spillovers across firms influence this link and introduces the basic framework which is further extended in Chapters 4 and 5 to allow for strategic interaction and multi-product firms respectively. In all these models technological progress takes the form of cost reductions. The model-setting considered in these Chapters belongs to the class of creative accumulation models, whose introduction in the economic literature is relatively recent and can be attributed to Smulders and van de Klundert and Peretto. Finally, Chapter 6 follows the creative destruction tradition initiated by Grossman and Helpman and Aghion and Howitt and develops a growth model with product quality innovations of random size. In all the Chapters of this dissertation, we adopt a normative perspective by comparing the market equilibrium solution to the optimal one.

This study explores the factors urban residents consider when making residential location decisions. The context of the study is informal residential areas in a rapidly urbanising African city – the city of Dar es Salaam in Tanzania. A central concern in the study is how the urban poor make their residential location decisions; the assumption is that with income limitations the urban poor rely on other non-economic resources to enable their residential location decisions in the context of rapid urban growth and urban poverty. The study attempts to question residential location choice concepts that rely on economic approaches as well as question explanations based on the developing world experiences.The study suggests that in the absence of reliable incomes, social networks and informalchannels prevail in the decision-making process. The concept of social capital where networks and social relationships are used as a resource by individuals or groups to achieve goals is explored in a residential choices framework. Demonstrated through in-depth interviews with heads of households settling close to the CBD (termed the inner city), the intermediate informal residential areas and the peri-urban residential areas; the study shows how socio-cultural factors play a role in the decision makingprocess of households. This is illustrated inter alia, in the form of informal channels for information on accommodation and residential plots, being accommodated rent-free by a relative, the actions of subsequently making short-distance moves to a location within proximity of a relative, or seeking people of the same socio-economic status. The context within which the actions have taken place has also been shown to be important in corroborating the network and relationship elements in the concept of social capital. The uncertainty that residents in rapidly urbanizing cities have to deal with on an everyday basis calls for networks and relations as an important resource for survival. The study goes further to suggest how urban planning practice can learn from the social processes. The study is based on qualitative methods such as in-depth interviewing with heads of household and key informants.

<p>Intraurban consumer behaviour is explained in this thesis by a conventional scientific method - a hypothesis about why we shop where we shop is empirically tested by observation and model calibration. Dynamic theory of the individual relative choice and a description of the spatial context of the perceived retail structure of Hamilton, Ontario, form the groundbase for hypothesizing a set of areal generalizations for single-stop, single-purpose shopping trips. The generalizations are 'general' statements about why people shop where they shop; specifically, grocery trips should be to an outlet located in the nearest shopping centre to place of residence, while non-grocery trips should be either to an outlet located in a nearby shopping centre when shopping for low-value goods, or to an outlet located anywhere in the city when shopping for high-value goods. The reason why these destinations should be chosen is so as to either maintain acquired utility levels over time when grocery, or low-value non-grocery, shopping or maximize acquired utility at one finite time period when high value non-grocery shopping. The areal generalisations are then tested by constructing trip flow maps and calibrating a multinomial logit model, using an observed aggregate shopping trip data set for Hamilton, Ontario. Both the floe maps of single-stop, single-purpose shopping trips and the estimated logit model coefficients and elasticity statistics, verify the areal generalisations. Thus the observed shopping trip flows for Hamilton, Ontario can be explained by the hypothesized areal generalisations; however, the mode of explanation can be spatially transferred to any city as the temporal relative choice theory of individual behaviour is universal. All that is required is a description of the spatial context in which the choice theory continues to operate. The thesis has thus shown how a conventional scientific method can explain rational behaviour, where to be "rational" is to be human, not deterministic.</p> / Master of Arts (MA)

Dans un contexte de carence méthodologique, cette thèse vise à apporter un nouveau souffle aux modèles de choix de localisation jusqu’ici incapables d’appréhender de manière réaliste la complexité des processus décisionnels des établissements tels que leurs choix de localisation optimale. Les modèles de choix de localisation utilisent des données géoréférencées, pour lesquelles les ensembles de choix ont une composante spatiale explicite. Il est donc essentiel de comprendre comment représenter l’aspect spatial dans les modèles de choix de localisation. La décision finale d’un établissement semble être liée au paysage économique environnant. La quantification du lien entre les observations voisines implique une prise de décision sur la spécification de la matrice spatiale. Pourtant, la grande majorité des chercheurs appliquent la métrique euclidienne sans considérer des hypothèses sous-jacentes et ses alternatives. Cette démarche a été initialement proposée en raison de données et de puissance informatique limitées plutôt que de son universalité. Dans les régions comme la région parisienne, oû la congestion ainsi que les problèmes de barrières physiques non traversables apparaissent clairement, les distances purement basées sur la topographie peuvent ne pas être les plus appropriées pour l’étude de la localisation intra-urbaine. Il est possible d’acquérir des connaissances en reconsidérant et en mesurant la distance en fonction du problème analysé. Plutôt que d’enfermer les chercheurs dans une structure restrictive de la matrice de pondération, cette thèse propose une approche souple pour identifier la métrique de distance la plus susceptible de prendre en compte correctement les marchés voisins selon le secteur considéré. En plus de la distance euclidienne standard, six autres mesures sont testées : les temps de déplacement en voiture (pour les périodes de pointe et hors pointe) et en transport en commun, ainsi que les distances de réseau correspondantes.Par ailleurs, les décisions d’un établissement particulier sont interdépendantes des choix d’autres acteurs, ce qui rend les choix de localisation particulièrement intéressants et difficiles à analyser. Ces problèmes épineux posés par l’interdépendance des décisions ne peuvent généralement être négligés sans altérer l’authenticité du modèle de décision d’établissement. Les approches classiques de la sélection de localisation échouent en ne fournissant qu’un ensemble d’étapes systématiques pour la résolution de problèmes sans tenir compte des interactions stratégiques entre les établissements sur le marché. L’un des objectifs de la présente thèse est d’explorer comment adapter correctement les modèles de choix de localisation pour étudier les choix discrets d’établissement lorsqu’ils sont interdépendants.En outre, une entreprise peut ouvrir un certain nombre d’unités et servir le marché à partir de plusieurs localisations. Encore une fois, la théorie et les méthodes traditionnelles peuvent ne pas convenir aux situations dans lesquelles les établissements individuels, au lieu de se situer indépendamment les uns des autres, forment une grande organisation, telle qu’une chaîne confrontée à une concurrence féroce d’autres chaînes. Le modèle prend en compte non seulement les interactions intra-chaînes mais aussi inter-chaînes. Aussi, la nécessité d’indiquer une nette différence entre la population de jour et de nuit a été soulignée. La demande est représentée par les flux de piétons et de voitures, la foule de clients potentiels passant par les centres commerciaux, les stations de trains et de métros, les aéroports et les sites touristiques. L’Enquête Globale Transport 2010 (EGT 2010), entre autres, est utile pour atteindre cet objectif. / This thesis is breathing new life into the location choice models of establishments. The need for methodological advances in order to more realistically model the complexity of establishment decision-making processes, such as their optimal location choices, is the key motivation of this thesis. First, location choice models use geo-referenced data, for which choice sets have an explicit spatial component. It is thus critical to understand how to represent spatial aspect in location choice models. The final decision of an establishment seems to be related to the surrounding economic landscape. When accounting for the linkage between neighboring observations, the decision on the spatial weight matrix specification must be made. Yet, researchers overwhelmingly apply the Euclidean metric without realizing its underlying assumptions and its alternatives. This representation has been originally proposed due to scarce data and low computing power, rather than because of its universality. In areas, such as the Paris region, where high congestion or uncrossable physical barriers problems clearly arise, distances purely based on topography may not be the most appropriate for the study of intra-urban location. There are insights to be gained by mindfully reconsidering and measuring distance depending on a problem being analyzed. Rather than locking researchers into a restrictive structure of the weight matrix, this thesis proposes a flexible approach to intimate which distance metric is more likely to correctly account for the nearby markets depending on the sector considered. In addition to the standard Euclidean distance, six alternative metrics are tested: travel times by car (for the peak and off-peak periods) and by public transit, and the corresponding network distances. Second, what makes these location choices particularly interesting and challenging to analyze is that decisions of a particular establishment are interrelated with choices of other players.These thorny problems posed by the interdependence of decisions generally cannot be assumed away, without altering the authenticity of the model of establishment decision making. The conventional approaches to location selection fail by providing only a set of systematic steps for problem-solving without considering strategic interactions between the establishments in the market. One of the goals of the present thesis is to explore how to correctly adapt location choice models to study establishment discrete choices when they are interrelated.Finally, a firm can open a number of units and serve the market from multiple locations. Once again, traditional theory and methods may not be suitable to situations wherein individual establishments, instead of locating independently from each other, form a large orgnization, such as a chain facing a fierce competition from other chains. There is a necessity to incorporate interactions between units within the same and competing firms. In addition, the need to state a clear difference between the daytime and nighttime population has been emphasized. Demand is represented by pedestrian and car flows, the crowd of potential clients passing through the commercial centers, train and subways stations, airports, and highly touristic sites. The Global Survey of Transport (EGT 2010), among others, is of service to reach this objective. More realistically designed location choice models accounting for spatial spillovers, strategic interaction, and with a more appropriate definition of distance and demand can become a powerful and flexible tool to assist in finding a befitting site. An appropriately chosen location in turn can make an implicative difference for the newly-created business. The contents of this thesis provide some useful recommendations for transport analysts, city planners, plan developers, business owners, and shopping center investors.

Les politiques françaises de redistribution locale sont relativement méconnues et ne font pas l'objet de beaucoup de travaux. Elles représentent pourtant un enjeu important. Elles regroupent une multitude de prestations sociales qui s'adaptent aux configurations familiales et territoriales. Elles sont un outil flexible, largement utilisé par les collectivités locales et peuvent avoir des effets non négligeables notamment sur les ménages en situation précaire.Le caractère décentralisé des politiques de redistribution locale fait émerger deux problématiques correspondant aux deux aspects étudiés dans cette thèse. D'une part, nous interrogeons les choix politiques qui guident l'offre de transferts sociaux locaux. Nous inscrivons notre réflexion dans le cadre des théories sur les interactions stratégiques, qui avancent que les élus locaux adoptent des comportements stratégiques basés sur la comparaison et prennent leurs décisions en fonction des collectivités voisines. Partant du constat que de nombreux travaux, dans plusieurs pays font état de la présence d'interactions stratégiques dans la fixation des taux d'imposition, nous nous concentrons sur l'aspect dépenses sociales. Nous montrons leur présence dans des choix de transferts sociaux au niveau local. Nous observons en effet des phénomènes de mimétisme. Notre analyse montre également que, entre les deux origines de ce mécanisme souvent avancées, la comparaison politique et la mobilité, la seconde joue un rôle significatif. Les collectivités locales tendent à augmenter leur niveau de générosité avec la faible mobilité des individus.En second lieu, cette thèse s'intéresse aux conséquences de la décentralisation des transferts sociaux locaux sur la demande des différents types de ménages en faveur de redistribution. Nous étudions les choix des ménages en termes de mobilité résidentielle et de localisation en fonction de l'offre de biens et services publics locaux. Nous questionnons ainsi les phénomènes de sélection adverse liés aux choix politiques locaux. Les résultats mettent l'accent sur le fait que les ménages défavorisés sont peu mobiles et connaissent plus de trajectoires résidentielles descendantes. Nous montrons également que la générosité des villes joue un rôle significatif dans la localisation des ménages. / French policies of redistribution set at the local level are little known and have not been the topic of many works. Yet they represent a major challenge. They include a multitude of benefits that fit family configurations in different territories. They are a flexible tool, widely used by local governments and which may have a significant impact on poor households.The decentralized nature of local redistribution policies naturally raises two main questions corresponding to the two aspects studied in this thesis. First, we question the political choices that guide the provision of local social transfers. We base our analysis on the literature about strategic interactions which suggests that local policy-makers adopt strategic behavior relying on the comparison of surrounding governments. Numerous studies in many countries have reported the presence of strategic interactions in the setting of local tax rates. Those focusing on the spending side are less frequent. We show that strategic interactions also exist when deciding the level of social transfers at the local level. One can observe mimicry mecanisms. Our work shows that, between the two origins of this phenomenon that are usually put forward, yardstick comparison and mobility, the second plays a significant role. Local authorities tend to increase their level of generosity when the mobility levels of individuals are low.Second, the other consequence of the decentralization of local social transfers is related to the different types of households' demand for redistribution. We study the choices of households in terms of residential mobility and location associated with the supply of local public goods and services. We question the adverse selection phenomena related to local political choices. The results emphasize the fact that poor households are less mobile and experience more downward residential trajectories. We also show that the generosity of cities plays a significant role in the location of the households.

Questa tesi analizza le determinanti e gli effetti dell'innovazione attraverso un'analisi empirica. Nel primo capitolo viene analizzato l'impatto delle leggi di proprietà intellettuale sull'innovazione domestica in campo farmaceutico. Nel secondo capitolo, in cui vengono usati dati a livello di impresa, si studia la correlazione tra innovazione, export, produttività e vincoli finanziari. Infine nell'ultimo capitolo si studia l'effetto dell'innovazione domestica nell'attrarre investimenti diretti esteri. Mentre nel primo e nell'ultimo capitolo l'innovazione viene misurata come output, usando il numero di brevetti attribuiti ad un determinato paese, nel secondo capitolo vengono usati dati di R&D, e quindi di input di innovazione. / This dissertation analyses the determinants and the effects of innovation using an empirical analysis. In the first chapter the impact of Intellectual Property Rights on domestic innovation in the pharmaceutical sector is estimated. In the second chapter the correlation between innovation, export, productivity and financial constraint is studied at the firm level. Finally, in the last chapter the role of domestic innovation in attracting Foreign Direct Investments is estimated. While in the first and in the last chapter innovation output is considered, and innovation is proxied by patent data, in the second chapter innovation input is taken into account, and R&D data are used.