Essays in economics of information

Cette thèse est une collection de trois articles en économie de l'information. Le premier chapitre sert d'introduction et les Chapitres 2 à 4 constituent le coeur de l'ouvrage. Le Chapitre 2 porte sur l’acquisition d’information sur l’Internet par le biais d'avis de consommateurs. En particulier, je détermine si les avis laissés par les acheteurs peuvent tout de même transmettre de l’information à d’autres consommateurs, lorsqu’il est connu que les vendeurs peuvent publier de faux avis à propos de leurs produits. Afin de comprendre si cette manipulation des avis est problématique, je démontre que la plateforme sur laquelle les avis sont publiés (e.g. TripAdvisor, Yelp) est un tiers important à considérer, autant que les vendeurs tentant de falsifier les avis. En effet, le design adopté par la plateforme a un effet indirect sur le niveau de manipulation des vendeurs. En particulier, je démontre que la plateforme, en cachant une partie du contenu qu'elle détient sur les avis, peut parfois améliorer la qualité de l'information obtenue par les consommateurs. Finalement, le design qui est choisi par la plateforme peut être lié à la façon dont elle génère ses revenus. Je montre qu'une plateforme générant des revenus par le biais de commissions sur les ventes peut être plus tolérante à la manipulation qu'une plateforme qui génère des revenus par le biais de publicité. Le Chapitre 3 est écrit en collaboration avec Marc Santugini. Dans ce chapitre, nous étudions les effets de la discrimination par les prix au troisième degré en présence de consommateurs non informés qui apprennent sur la qualité d'un produit par le biais de son prix. Dans un environnement stochastique avec deux segments de marché, nous démontrons que la discrimination par les prix peut nuire à la firme et être bénéfique pour les consommateurs. D'un côté, la discrimination par les prix diminue l'incertitude à laquelle font face les consommateurs, c.-à-d., la variance des croyances postérieures est plus faible avec discrimination qu'avec un prix uniforme. En effet, le fait d'observer deux prix (avec discrimination) procure plus d'information aux consommateurs, et ce, même si individuellement chacun de ces prix est moins informatif que le prix uniforme. De l'autre côté, il n'est pas toujours optimal pour la firme de faire de la discrimination par les prix puisque la présence de consommateurs non informés lui donne une incitation à s'engager dans du signaling. Si l'avantage procuré par la flexibilité de fixer deux prix différents est contrebalancé par le coût du signaling avec deux prix différents, alors il est optimal pour la firme de fixer un prix uniforme sur le marché. Finalement, le Chapitre 4 est écrit en collaboration avec Sidartha Gordon. Dans ce chapitre, nous étudions une classe de jeux où les joueurs sont contraints dans le nombre de sources d'information qu'ils peuvent choisir pour apprendre sur un paramètre du jeu, mais où ils ont une certaine liberté quant au degré de dépendance de leurs signaux, avant de prendre une action. En introduisant un nouvel ordre de dépendance entre signaux, nous démontrons qu'un joueur préfère de l'information qui est la plus dépendante possible de l'information obtenue par les joueurs pour qui les actions sont soit, compléments stratégiques et isotoniques, soit substituts stratégiques et anti-toniques, avec la sienne. De même, un joueur préfère de l'information qui est la moins dépendante possible de l'information obtenue par les joueurs pour qui les actions sont soit, substituts stratégiques et isotoniques, soit compléments stratégiques et anti-toniques, avec la sienne. Nous établissons également des conditions suffisantes pour qu'une structure d'information donnée, information publique ou privée par exemple, soit possible à l'équilibre.This thesis is a collection of three essays in economics of information. Chapter 1 is a general introduction and Chapters 2 to 4 form the core of the thesis. Chapter 2 analyzes information dissemination on the Internet. Online platforms such as Amazon, TripAdvisor or Yelp are now key sources of information for modern consumers. The proportion of consumers consulting online reviews prior to purchasing a good or a service has grown persistently. Yet, sellers have been accused of hiring shills to post fake reviews about their products. This raises the question: Does the presence of shills make reviews less informative? I show that the answers to this question depend on the way the platform presents and summarizes reviews on its website. In particular, I find that withholding information by garbling the reviews benefits information dissemination by inducing the seller to destroy less information with manipulation. Next, I show that the platform's choice regarding how to present reviews hinges on its revenue source. Indeed, a platform that receives sales commissions optimally commits to publishing information differently from a platform that receives revenues from advertisements or from subscription fees. Incidentally, such platforms have contrasting impacts on the amount of information that is transmitted by reviews. Chapter 3 is co-authored with Marc Santugini. In this chapter, we study the impact of third-degree price discrimination in the presence of uninformed buyers who extract noisy information from observing prices. In a noisy learning environment, it is shown that price discrimination can be detrimental to the firm and beneficial to the consumers. On the one hand, discriminatory pricing reduces consumers’ uncertainty, i.e., the variance of posterior beliefs upon observing prices is reduced. Specifically, observing two prices under discriminatory pricing provides more information than one price under uniform pricing even when discriminatory pricing reduces the amount of information contained in each price. On the other hand, it is not always optimal for the firm to use discriminatory pricing since the presence of uninformed buyers provides the firm with the incentive to engage in noisy price signaling. Indeed, if the benefit from price flexibility (through discriminatory pricing) is offset by the cost of signaling quality through two distinct prices, then it is optimal to integrate markets and to use uniform pricing. Finally, Chapter 4 is co-authored with Sidartha Gordon. In this chapter, we study a class of games where players face restrictions on how much information they can obtain on a common payoff relevant state, but have some leeway in covertly choosing the dependence between their signals, before simultaneously choosing actions. Using a new stochastic dependence ordering between signals, we show that each player chooses information that is more dependent on the information of other players whose actions are either isotonic and complements with his actions or antitonic and substitutes with his actions. Similarly, each player chooses information that is less dependent on the information of other players whose actions are antitonic and complements with his actions or isotonic and substitutes with his actions. We then provide sufficient conditions for information structures such as public or private information to arise in equilibrium

What Hope Lies Buried Here: Differential Mortality and Mortuary Treatment of Adolescents in Dubuque's Third Street Cemetery

Appendix C is available at https://doi.org/10.24378/exe.2763 and Appendix D is available at https://doi.org/10.24378/exe.2764Excavations at the Catholic Third Street Cemetery in Dubuque, Iowa (2007-2011), uncovered 939 unmarked graves dating to the period between 1833 and 1880. Skeletal analysis identified 43 individuals whose age estimate ranges overlapped with osteological (12 to 20 years) and social (13 to 19 years) adolescence, as defined for this cultural context. The current research design focused on mortality patterns and mortuary preparations of these individuals and highlights differences between teenagers and the rest of the cemetery population. This interdisciplinary project utilised data from osteological analyses and archival research to explore health and mortality among adolescent non-survivors. Palaeopathological observations reflecting early life health insults (linear enamel hypoplasias, cribra orbitalia, porotic hyperostosis) and later illness (labyrinthine endocranial lesions, periosteal new bone formation, tubercular lesions) were studied to explore the potential vulnerability of adolescents with frailty acquired through earlier health stresses. Perimortem trauma and local death records were examined to determine the proportion of teenage mortality due to external causes such as accidents, homicide, and suicide. The lack of perimortem trauma observed in the Third Street adolescent sample was explained to some extent by the number of teenagers who perished from, but were unmarked by, a single accidental cause – drowning. The investigation of mortuary treatment examined combinations of burial attributes – including coffin hardware, burial clothing, religious objects, and nonreligious grave goods – and demonstrated how age-related patterns reflect an increase in socially acceptable sentimentality and changing views of the afterlife, with preferential treatment afforded to some adolescents. Comparative pathological marker and burial attribute data were gathered from publications on nine additional nineteenth-century burial populations, and death records from a tenth were consulted. Despite issues with inconsistent data collection procedures for parts of the comparative sample, results tentatively support the observations from Third Street. The proportion of adolescents with both early-life stress markers and later pathological manifestations is higher than that of other age classes, suggesting that survival of health insults in infancy or early childhood left teenagers more susceptible to fatal disease, particularly when their immune systems were vulnerable due to competing pubertal energy investments. Observed regional differences in skeletal marker rates suggest that this “double signal” may be more pronounced in populations with a high prevalence of TB. Perimortem trauma levels are equal to those of adults, though greater evidence of violence in the South and Southwest reflects the unstable social conditions in those areas. Regional, as well as temporal, trends were also identified in adolescent funerary preparations. Mid-nineteenth-century adolescents received preferential treatment, though general increases in mortuary elaboration overshadow this distinction in some later cemetery populations. Parental grief at the loss of near-adult offspring was expressed in the tendency to employ the metaphor of death as a journey when preparing adolescents for the grave, instead of the metaphor of sleep applied to younger children. Meanwhile, in frontier areas, independently living teenagers were often interred without familial involvement in the equivalent of paupers’ graves

Colonialisms, post-colonialisms and lusophonies: proceedings of the 4th International Congress in Cultural Studies

Colonialismos e pós-colonialismos são todos diferentes, mesmo quando referidos exclusivamente à situação lusófona. Neste contexto, mais do que procurar boas respostas, importa determinar quais as questões pertinentes aos nossos colonialismos e pós-colonialismos lusófonos. Com efeito, problematizar a própria questão é começar por descolonizar o pensamento. Em nosso entender, esta é uma das tarefas candentes no processo de re-imaginação da Lusofonia, que passa, atualmente, pela procura de um pensamento estratégico que inclua uma reflexão colonialista/pós-colonialista/descolonialista. Esta tarefa primeira, e mesmo propedêutica a qualquer construção gnoseológica, de descolonizar o pensamento hegemónico onde quer que ele se revele, não pode deixar de implicar as academias, centros de produção do saber e do conhecimento da realidade cultural, política e social. Neste sentido, descolonizar o pensamento sobre a Lusofonia passará por colocar em causa e instabilizar o que julgamos já saber e ser como ‘sujeitos lusófonos’, ‘países lusófonos’, ‘comunidades lusófonas’. Trata-se, assim, de instabilizar a uniformidade, mas também as diferenças instituídas, que frequentemente não são mais do que um novo género de cânone integrador e dissolvente da diferença. Por outro lado, não podemos deixar de praticar uma atitude vigilante, de cuidado e suspeição, em face do discurso sobre a diferença irredutível, que pode tornar-se (como no passado) na estéril celebração do exótico. Fazer com que a diferença instabilize o que oficialmente se encontra canonizado como ‘diferença dentro do cânone’, implica negociar e re-inscrever identidades sem inverter dualismos. Uma reflexão pós-colonial no contexto lusófono não pode evitar o exercício da crítica às antigas dicotomias periferia/centro; cosmopolitismo/ruralismo, civilizado/selvagem, negro/branco, norte/sul, num contexto cultural de mundialização, transformado por novos e revolucionários fenómenos de comunicação, que têm também globalizado a marginalidade. A tarefa de re-imaginar a Lusofonia implicará necessariamente a deslocação, inversão ou até implosão, do pensamento dual eurocêntrico, obrigando-nos a repensá-la dentro de uma mais vasta articulação entre local e global

Colonialisms, post-colonialisms and lusophonies: Proceedings of the 4th International Congress in Cultural Studies

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Anales del XIII Congreso Argentino de Ciencias de la Computación (CACIC)

Contenido: Arquitecturas de computadoras Sistemas embebidos Arquitecturas orientadas a servicios (SOA) Redes de comunicaciones Redes heterogéneas Redes de Avanzada Redes inalámbricas Redes móviles Redes activas Administración y monitoreo de redes y servicios Calidad de Servicio (QoS, SLAs) Seguridad informática y autenticación, privacidad Infraestructura para firma digital y certificados digitales Análisis y detección de vulnerabilidades Sistemas operativos Sistemas P2P Middleware Infraestructura para grid Servicios de integración (Web Services o .Net)Red de Universidades con Carreras en Informática (RedUNCI