Modeling consumer behaviour in the presence of network effects

Consumer choice models are a key component in fields such as Revenue Management and Transport Logistics, where the demands for certain products or services are assumed to follow a particular form, and sellers or market-makers use that information to adjust their strategies accordingly, choosing for example which products to display (assortment problem) or their prices (pricing problem). In the last couple of decades, online markets have taken a lot of relevance, providing a setting where consumers can compare easily different products, before deciding to buy them. More information is now available, and the purchasing decisions not only depend on the quality, prices and availability of the products, but also on what previous consumers think about them (phenomenon commonly known as Network Effects). Hence, in order to create a suitable model for this kind of market, it is relevant to understand how the collective decisions affect the market evolution. In this thesis we consider a particular subset of those online markets, cultural markets, where the products are for example songs, video games or ebooks. This kind of market has the special feature that its products have unlimited supply (since they are just a digital copy), and therefore we can exploit this in our models, to justify assumptions of the asymptotic behaviour of the market. We study some variations of the traditional Multinomial Logit (MNL) model, characterising the behaviour of consumers, where their purchasing decisions are affected by the quality and prices (initially fixed) of the available products, as well as their visibilities in the market interface and the consumption patterns of previous users. We focus particularly on the parameters associated to the network effects, where depending on the strength of the network effects, it is possible to explain: herd behaviours, where an alternative overpowers the rest; as well as more well-distributed settings, where all the alternatives receive enough attention giving a notion of fairness, since higher quality products get a larger market share. Finally, using the model where market shares are distributed according to the quality of the products, we study pricing strategies, where sellers can either collaborate or compete. We analyse the effect of both type of strategies into the choice model

¿Cómo participa la historia de la aritmética en un curso de formación inicial de profesores de matemáticas?

En este escrito presentamos parte de los resultados de un estudio que se llevó a cabo en el marco de la línea de investigación sobre el conocimiento del profesor de matemáticas, de la Maestría en Docencia de la Matemática en la Universidad Pedagógica Nacional, el cual se realizó con el fin de caracterizar el papel que cumple la historia de la aritmética en la formación inicial de profesores. Nos centramos específicamente en cómo participa la historia en un curso de la Licenciatura en Matemáticas en el cual se aborda el conocimiento pedagógico de contenido y en el que además interviene la historia de la aritmética

Differences in the distribution and abundance of Teredinidae (Mollusca: Bivalvia) along the coast of Rio de Janeiro state, Brazil

Teredinidae são moluscos marinhos ou estuarinos perfuradores e degradadores de madeira. Avaliar sua distribuição e abundância se mostrou importante, uma vez que a destruição de madeira é ainda subestimada, sobretudo em regiões tropicais. Dados de literatura têm mostrado também que temperatura e salinidade são dois fatores que afetam fisiologicamente as espécies de Teredinidae. Os objetivos deste trabalho foram avaliar a distribuição e abundância de Teredinidae ao longo da costa do Rio de Janeiro, em relação ao padrão de temperatura e sua variação. Coletores artificiais de pinho foram imersos por três meses em 14 localidades em quatro regiões do estado. Sete espécies foram registradas e identificadas pela forma de suas palhetas. Os maiores valores de densidade e riqueza específica foram registrados na Baía da Ilha Grande e os menores, na Baía de Guanabara. Foi observado um gradiente na abundância relacionado à temperatura. As espécies mais abundantes foram Lyrodus floridanus e Teredo furcifera. Além da temperatura, a diferença na disponibilidade de madeira entre as regiões parece ser também um fator importante. Pela primeira vez registramos a ocorrência de Bankia destructa para o Rio de Janeiro, embora este registro não signifique introdução ou expansão de distribuição.Teredinidae are wood-boring mollusks found in marine and estuarine regions. Evaluation of the distribution and abundance of Teredinidae is a very important task, as the impact of the destruction of wood in man-made structures is still underestimated, mainly in tropical regions. It is also know that temperature and salinity are key factors affecting the abundance and activity of Teredinidae due to their effects on the physiological responses of Teredinidae. The aim of this study was to evaluate the distribution and abundance of Teredinidae along the Rio de Janeiro coast according to temperature range and pattern. Artificial pine collectors were used and remained immersed for three months in four regions at 14 sites. We recorded seven species of Teredinidae, identified according to their pallets. Ilha Grande Bay was the region with the highest density and species richness, and the region with the lowest was Guanabara Bay. One gradient of abundance related to temperature was found. The most abundant species were Lyrodus floridanus and Teredo furcifera. Besides temperature, wood availability among regions was another important factor. For the first time, we recorded the occurrence of Bankia destructa on the Rio de Janeiro coast, but this record does not indicate any species introduction or expanding distribution range

Beyond the mincer equation: the internal rate of return to higher education in Colombia

In order to present an estimation of the Internal Rate of Return (IRR) to higher education in Colombia we take advantage of the methodological approach provided by Heckman, Lochner and Todd (2005). Trying to overcome the criticism that surrounds interpretations of the education coefficient of Mincer equations as being the rate ofreturn to investments in education we develop a more structured approach of estimation, which controls for selection bias, includes more accurate measures of labor income and the role of education costs and income taxes. Our results implied a lower rate of return than the ones found in the Colombian literature and show that the Internal Rate ofReturn for higher education in Colombia lies somewhere between 0.074 and 0.128. The results vary according to the year analyzed and individual´s gender. This last result reinforces considerations regarding gender discrimination in the Colombian labor market.Education returns, Mincer Equation, Internal Rate of Return, Colombia

Propuesta de un método de control de calidad mediante visión artificial para las cabezas de tornillos hexagonales en una empresa específica de Bogotá

Ingeniero (a) IndustrialPregrad

Novo Fútbol S.A.S

Novo Fútbol nació como una iniciativa para desarrollar espacios que puedan promover la profesionalización de la industria del fútbol. En el principio surgió como una propuesta simple de hacer un Foro relacionado con temas de gestión deportiva, sin embargo con el tiempo la idea se fue desarrollando hasta llegar a lo que es hoy la marca Novo Fútbol. Hoy Novo Fútbol pretende convertirse en un movimiento a nivel nacional que pueda impulsar y ejecutar proyectos con el propósito fundacional de mejorar la industria del fútbol en el país y también utilizar este deporte como herramienta de transformación social para Colombia.Introducción. Resumen Ejecutivo. Canvas / Modelo de Negocio. Análisis del entorno y tendencias. Plan de mercado. Plan financiero. Plan organizacional y jurídico. Conclusiones. Bibliografía. Anexos.Administrador de EmpresasPregrad

Nacionalidade versus extradição no caso Cláudia Sobral : um novo contorno para uma antiga problemática

O presente trabalho tem como objetivo estudar o direito fundamental à nacionalidade e o instituto da extradição através da análise de um caso concreto que teve grande repercussão na ordem jurídica nacional: o da perda de nacionalidade brasileira originária e a extradição de Cláudia Cristina Sobral. Do presente estudo, almeja-se inferir se houve violação do artigo 5°, LI, e da garantia de não-extraditabilidade de brasileiro nato, ou se as disposições constitucionais acerca do direito fundamental à nacionalidade contidas no artigo 12, § 4º, II, alínea “b”, indicariam a não ocorrência de qualquer contraposição entre direitos fundamentais. Como metodologia é utilizado o método dedutivo, com base em pesquisa bibliográfica, jurisprudencial e constitucional para que seja possível extrair alguma conclusão à hipótese apresentada. No primeiro capítulo, é estudado o direito fundamental à nacionalidade, sua importância em seara nacional e internacional e as formas de aquisição e perda do direito à nacionalidade. Ao final, analisa-se a maneira como ocorreu a perda da nacionalidade de Cláudia Sobral, através da denegação da ordem no Mandado de Segurança 33.864/DF e da confirmação da decisão de Ministro de Estado da Justiça que, por delegação presidencial, declarou a perda de nacionalidade brasileira primária estudada nesse trabalho. No segundo capítulo, é estudado o instituto da extradição, e ao final é analisado o Pedido de Extradição 1.462/DF, verificando-se de que maneira se operou a extradição de Cláudia Sobral e a consonância desse fato com aspectos doutrinários e constitucionais estudados na segunda parte da monografia.The present work aims to study the fundamental right to nationality and the extradition institute, through the analysis of a specific case of great repercussions in the national legal order: the loss of the Brazilian birthright nationality and the extradition of Cláudia Cristina Sobral. The present study aims to infer whether there was a violation of the Article 5, LI, and thus the guarantee of no extradition of a Brazilian born, or whether the constitutional provisions on the fundamental right to nationality, contained in Article 12, § 4, II, item “b”, would indicate the absence of any opposition between fundamental rights. As a methodological approach the deductive method is applied, based on bibliographic, jurisprudential and constitutional research so that it enables the possibility to draw some conclusion to the hypothesis presented in this work. In the first chapter, the fundamental right to nationality is examined, its importance in the national and international fields and the forms of loss and acquisition of the right to nationality. Utmost, it analyzes the means in which Cláudia Sobral's loss of nationality occurred, through the order denial in the Writ of Mandate 33.864 / DF and the confirmation of the decision of the Minister of State of Justice who, by presidential delegation, declared the loss of Brazilian birthright nationality studied in this work. In the second chapter, the extradition institute is studied, and at the end, the Extradition Request 1.462 / DF is analyzed, verifying how Cláudia Sobral's extradition was carried out and its consistency amidst the doctrinal and constitutional aspects studied in the second part of the present monograph

Evaluación de una vivienda de emergencia de la fundación Techo Ecuador usando la Norma ecuatoriana de la construcción 2013 (NEC-13), capítulo 7, construcción con madera y elaboración de una propuesta de mejora

This investigation will check the fulfillment of the chapter 7 of the 2013 Ecuadorean Construction Norm of the houses built by the organization Techo Ecuador. These houses are built for families that live in extreme poverty situation or homeless families. Chapter 7 regulates the use of wood as a construction material. The houses that Techo build are prefabricated house made with wood panels; they also have a light steel roof. The topics proposed in chapter 7 are going to be revised one by one and are going to be compared with the current characteristics of the Techo houses. After the results are obtained modifications for improvement are going to be suggested. These modifications should not change the emergency houses characteristics nor should they increase the cost of the house significantly.En esta investigación se revisará el cumplimiento del capítulo 7 de la Norma Ecuatoriana de la Construcción 2013 de las viviendas de emergencia que construye la fundación Techo Ecuador para familias que viven situación de pobreza, pobreza extrema o indigencia. El capítulo 7 hace referencia a la construcción en madera. Las viviendas que construye Techo son viviendas prefabricadas con paneles de madera y cubierta de acero galvanizado. Se revisará uno por uno los temas propuestos en el capítulo 7 y se los comparará con lo que viene realizando la fundación hasta la actualidad. Una vez realizado el análisis se revisarán los resultados y se propondrán mejoras al modelo actual con el fin del lograr el cumplimiento absoluto de la Norma. Los cambios propuestos deben mantener las características de vivienda de emergencia iniciales y no puede aumentar significativamente el precio de la vivienda

¿A qué llamamos historia de la aritmética? Una respuesta a través de cinco trazas

En este documento se responde la pregunta que hace parte del título desde cinco trazas diferentes pero interrelacionadas, a saber: la historia del número, la historia de los sistemas de numeración, la historia de los sistemas numéricos, la historia de la teoría de números y la historia de la logística. Esta respuesta analítica, constituye parte del marco de referencia usado para caracterizar el papel de la historia de la aritmética en la formación inicial de profesores de matemáticas