Social Security, Education, Retirement and Growth

In this paper we analyze the effects of social security policies in an unfunded, earnings-related social security system on the incentives to education investment and voluntary retirement, on growth and on income inequality. Growth is endogenously driven by human capital investment, individuals differ in their innate (learning) ability at birth, and the pension scheme includes a minimum pension. More skilled individuals spend more on education, minimum pensions reduce low skill individuals' incentives to invest in human capital, there is no monotonic relationship between per capita growth and income inequality.

Life Expectancy, Human Capital, Social Security and Growth

Revised: 2006-11.-- Published as an article in: Journal of Public Economics 90(12), December, 2006, pp. 2323-2349.

Analytical efficiency evaluation of a network mobility management protocol for Intelligent Transportation Systems

One of the major concerns in an Intelligent Transportation System (ITS) scenario, such as that which may be found on a long-distance train service, is the provision of efficient communication services, satisfying users' expectations, and fulfilling even highly demanding application requirements, such as safety-oriented services. In an ITS scenario, it is common to have a significant amount of onboard devices that comprise a cluster of nodes (a mobile network) that demand connectivity to the outside networks. This demand has to be satisfied without service disruption. Consequently, the mobility of the mobile network has to be managed. Due to the nature of mobile networks, efficient and lightweight protocols are desired in the ITS context to ensure adequate service performance. However, the security is also a key factor in this scenario. Since the management of the mobility is essential for providing communications, the protocol for managing this mobility has to be protected. Furthermore, there are safety-oriented services in this scenario, so user application data should also be protected. Nevertheless, providing security is expensive in terms of efficiency. Based on this considerations, we have developed a solution for managing the network mobility for ITS scenarios: the NeMHIP protocol. This approach provides a secure management of network mobility in an efficient manner. In this article, we present this protocol and the strategy developed to maintain its security and efficiency in satisfactory levels. We also present the developed analytical models to analyze quantitatively the efficiency of the protocol. More specifically, we have developed models for assessing it in terms of signaling cost, which demonstrates that NeMHIP generates up to 73.47% less signaling compared to other relevant approaches. Therefore, the results obtained demonstrate that NeMHIP is the most efficient and secure solution for providing communications in mobile network scenarios such as in an ITS context.

Effects of international trade of food and feed and human diet shifts on food security and environmental safety: integrating scales

4 p.

Diseño de recintos blindados para gammagrafía industrial.

[ES]El proyecto incluido en este trabajo de fin de grado trata sobre el diseño de una instalación blindada para realización de gammagrafía industrial. Para poder realizar este ensayo es necesario un escudo que haga frente a la radiación de manera efectiva, con el fin de reducir la posibilidad de daños en la salud de aquellos individuos que se encuentren en las inmediaciones. Para calcular el espesor necesario se usará el software MCNPX, herramienta para el estudio de interacción de radiación con la materia. Debido a la naturaleza invisible e indetectable por medios naturales son necesarios unos protocolos de uso muy estrictos y grandes medidas de seguridad con la finalidad de evitar problemas de salud o accidentes