Numerical Distribution Functions for Seasonal Unit Root Tests

When working with time series data observed at intervals smaller than a year, it is often necessary to test for the presence of seasonal unit roots. One of the most widely used methods for testing seasonal unit roots is that of HEGY, which provides test statistics with non-standard distributions. This paper describes a generalisation of this method for any periodicity and uses a response surface regressions approach to calculate the critical values and P values of the HEGY statistics whatever the periodicity and sample size of the data. The algorithms are prepared with the Gretl open source econometrics package and some new tables of critical values for daily, hourly and half-hourly data are presented.seasonality, unit roots, surface response analysis

A model for hypermedia learning environments based on electronic books

Designers of hypermedia learning environments could take advantage of a theoretical scheme which takes into account various kinds of learning activities and solves some of the problems associated with them. In this paper, we present a model which inherits a number of characteristics from hypermedia and electronic books. It can provide designers with the tools for creating hypermedia learning systems, by allowing the elements and functions involved in the definition of a specific application to be formally represented A practical example, CESAR, a hypermedia learning environment for hearing‐impaired children, is presented, and some conclusions derived from the use of the model are also shown

Towards a Reliable Comparison and Evaluation of Network Intrusion Detection Systems Based on Machine Learning Approaches

Presently, we are living in a hyper-connected world where millions of heterogeneous devices are continuously sharing information in different application contexts for wellness, improving communications, digital businesses, etc. However, the bigger the number of devices and connections are, the higher the risk of security threats in this scenario. To counteract against malicious behaviours and preserve essential security services, Network Intrusion Detection Systems (NIDSs) are the most widely used defence line in communications networks. Nevertheless, there is no standard methodology to evaluate and fairly compare NIDSs. Most of the proposals elude mentioning crucial steps regarding NIDSs validation that make their comparison hard or even impossible. This work firstly includes a comprehensive study of recent NIDSs based on machine learning approaches, concluding that almost all of them do not accomplish with what authors of this paper consider mandatory steps for a reliable comparison and evaluation of NIDSs. Secondly, a structured methodology is proposed and assessed on the UGR'16 dataset to test its suitability for addressing network attack detection problems. The guideline and steps recommended will definitively help the research community to fairly assess NIDSs, although the definitive framework is not a trivial task and, therefore, some extra effort should still be made to improve its understandability and usability further

Immigrants in Spain: skills acquisition and development. A regional study

The consequences of international migration for development in countries of origin and destination remain hotly debated. The immigration flows could be considered an appropriate mechanism to contribute to the development of origin countries if they recognize the qualifications of immigrants or contribute to the acquisition of skills. Correspondence analysis is used to determine the relation between education level, job position and legal situation of immigrants in Spain. The results indicate that immigrants are occupying non skilled tasks, even in the case of well educated immigrants. Furthermore, these immigrants have no options to increase their skills nor by experience (in the job) neither by theirself (attending a school), since the immigration police only authorizes very short migration. Then, Spain is not contributing appropriately to the development of origin countries.

Museos en la encrucijada: estructuras, redes y retos en el País Vasco

Se realiza una descripción y un diagnóstico de los museos de Euskadi creados a lo largo del siglo XX. Este recorrido museológico lo divide en tres periodos, determinados por la propia historia del País Vasco: (a) desde comienzos del siglo XX hasta la Guerra Civil (1936), (b) los años de la Dictadura franquista y (c) desde 1975 hasta la actualidad. Si hasta 1975 había 14 museos en Euskadi, en el tercer periodo pasan a ser 108. Para Balerdi, el salto a la Modernidad se hizo tarde y de una manera enfebrecida. De esa proliferación, el mayor número corresponde a los museos etnográficos y locales que se han encargado de representar y visualizar el pasado del país; el de un mundo desaparecido o en vías de hacerlo. Por el contrario, la Modernidad y Posmodernidad de Euskadi ha sido y es una cuestión que atañe básicamente a los museos de arte contemporáneo

El realismo mágico

1 archivo PDF (3 páginas). fhduodevigint

Danone SA, a valuation of a centennial company

The present Dissertation aims to obtain the value of the multinational dairy company Danone as of 2019. In order to determine what is the aforementioned company worth, this document employs two different valuation techniques. First, the Discounted Cash Flow model is applied, and a target price is derived based upon Danone’s intrinsic value. Additionally, Danone’s value is computed through a comparison approach considering how similar firms are valued in the market. More specifically, this document employs the EV/EBITDA and PE multiples. Data was retrieved from both the Financial Report presented by Danone in February of 2019 as well as from the Thomson Reuters Eikon software, the OECD Economic Outlook and estimates from Damodaran website. A DCF base case scenario involving multiple growth and cost of capital assumptions is presented. Following Danone’s internal reporting and forecasting approach, the author develops two additional scenarios with potential risks and opportunities, divided into High and Medium according to their probability of materializing. The outcome from both methodologies results in a valuation range of €65.5 and €88.6, close to which the most accurate target price for Danone is to be found. Derived from a detailed and extensive analysis of the company’s intrinsic value, this target price is €88.77, implicitly suggesting a Strong Buy recommendation from the author.A presente Dissertação tem como objetivo principal determinar o valor atual da companhia multinacional de lacticínios Danone. A fim de quantificar qual é o valor líquido da empresa acima mencionada, o presente documento utiliza duas técnicas de avaliação diferentes. Em primeiro lugar, aplica o método do cash flow atualizado, conseguindo assim um preço-alvo baseado no valor intrínseco da Danone. Além disso, calcula o preço por ação através dum método de comparação, mediante o qual considera ativos similares no mercado e o valor dos mesmos. Mais especificamente, este documento emprega os múltiplos EV/EBITDA e PE. Os dados foram obtidos quer do relatório financeiro apresentado pela Danone em 2019 quer do software Thomson Reuters Eikon, o último Economic Outlook publicado pela OCDE assim como estimativas do website de Damodaran. Um cenário de base relativo ao método do cash flow atualizado é apresentado, incluindo uma série de pressupostos relativos ao crescimento futuro e ao custo de capital. Baseado nos relatórios internos e o método de previsão da Danone, o autor desenvolve dois cenários adicionais com riscos e oportunidades potenciais, divididos em High e Medium segundo a probabilidade de se materializarem. Os resultados da aplicação das duas metodologias, nomeadamente o preço-alvo da Danone, variam entre €65.5 e €88.6, perto dos quais se encontra o preço por ação mais preciso. Este preço-alvo é de €88.77 e é obtido após uma análise extensa e detalhada do valor intrínseco da companhia, o qual sugere implicitamente uma recomendação Strong Buy

On the mathematical analysis of the limit case of a radiative—convective climate model

We study the limit case corresponding to a model introduced by G.L. Stenchikov and A. Robock for the evolution of the temperature of an atmospheric column in absence of humidity. The model envolves a degenerate noncoercive quasilinear equation. The diffusion coefficient depends of the atmospheric stability and vanishes on the stable regions. We show the existence and uniqueness of a suitable class of weak solutions and prove that the number of stable and unstable regions are nonincreasing in time

Comunicación y entorno familiar: lenguaje y adquisición de la noción de cantidad por niños y niñas preescolares con audición diferenciada y lenguaje limitado: diseño y producción del mensaje

El presente informe reporta los resultados obtenidos de la fase correspondiente a la producción de medios didácticos, dentro del Aula Entorno [AE] (Díaz, I., & Garnica, I., 2010, p.3) para mejorar la comunicación madre-hijo [MH] en cuanto a la noción de cantidad al realizar tareas en el entorno familiar. El método consiste en comprender las fenomenologías que acontecen en las aulas de Matemática Educativa (Escuela Oral; Escuela de Lenguaje y Aprendizaje) y la de la Escuela para Padres del Instituto Mexicano de la Audición y el lenguaje, AC [IMAL] -Cinvestav (Garnica, I., & González, H. 2009 p. 277)

Marketing digital y redes sociales : camino hacia la igualdad

El uso de Internet ha crecido durante los últimos años en unos porcentajes bastante elevados. La creación de dispositivos y la duplicidad del uso de estas herramientas, han conseguido proliferar nuevas formas de comunicación que son las Redes Sociales, consiguiendo que la comunicación unidireccional se convirtiera en bidireccional. Este hecho ha afectado de lleno a los medios de comunicación convencional, como son la televisión, la radio, la prensa o las revistas. El problema se enmarca cuando las agencias de publicidad han intervenido dentro de las plataformas digitales han volcado los anuncios como si del mundo offline se tratara y, por lo tanto, no están alimentando de manera correcta la experiencia del usuario. Las mujeres juegan un papel muy importante dentro del mundo digital, ya que le corresponde un alto porcentaje de la actividad que se produce en las redes sociales y en diferentes plataformas que están interactuando. No obstante, tampoco hay que obviar la falta de rigurosidad por parte de empresas y marcas en el momento de realizar acciones de marketing, ya que se prevé que productos masculinos los feminicen y los lanzan al mercado, produciendo cierto descontento dentro de la parte de esta sociedad. Por lo tanto, hay que realizar un examen exhaustivo de cómo se está planteando este canal de comunicación y qué tipo de comercialización de productos se están destinando