Extended Coverage for Public Safety and Critical Communications Using Multi-hop and D2D Communications

In this thesis, we proposed the use of device-to-device (D2D) communications for extending the coverage area of active base stations, for public safety communications with partial coverage. A 3GPP standard compliant D2D system level simulator is developed for HetNets and public safety scenarios and used to evaluate the performance of D2D discovery and communications underlying cellular networks. For D2D discovery, the benefits of time-domain inter-cell interference coordi- nation (ICIC) approaches by using almost blank subframes were evaluated. Also, the use of multi-hop is proposed to improve, even further, the performance of the D2D discovery process. Finally, the possibility of using multi-hop D2D communications for extending the coverage area of active base stations was evaluated. Improvements in energy and spectral efficiency, when compared with the case of direct UE-eNB communi- cations, were demonstrated. Moreover, UE power control techniques were applied to reduce the effects of interference from neighboring D2D links.

Estratégias distribuídas para a coexistência de redes de banda larga sem fio em bandas não-licensiadas

The increasing demand for Internet data traffic in wireless broadband access networks requires both the development of efficient, novel wireless broadband access technologies and the allocation of new spectrum bands for that purpose. The introduction of a great number of small cells in cellular networks allied to the complimentary adoption of Wireless Local Area Network (WLAN) technologies in unlicensed spectrum is one of the most promising concepts to attend this demand. One alternative is the aggregation of Industrial, Science and Medical (ISM) unlicensed spectrum to licensed bands, using wireless networks defined by Institute of Electrical and Electronics Engineers (IEEE) and Third Generation Partnership Project (3GPP). While IEEE 802.11 (Wi-Fi) networks are aggregated to Long Term Evolution (LTE) small cells via LTE / WLAN Aggregation (LWA), in proposals like Unlicensed LTE (LTE-U) and LWA the LTE air interface itself is used for transmission on the unlicensed band. Wi-Fi technology is widespread and operates in the same 5 GHz ISM spectrum bands as the LTE proposals, which may bring performance decrease due to the coexistence of both technologies in the same spectrum bands. Besides, there is the need to improve Wi-Fi operation to support scenarios with a large number of neighbor Overlapping Basic Subscriber Set (OBSS) networks, with a large number of Wi-Fi nodes (i.e. dense deployments). It is long known that the overall Wi-Fi performance falls sharply with the increase of Wi-Fi nodes sharing the channel, therefore there is the need for introducing mechanisms to increase its spectral efficiency. This work is dedicated to the study of coexistence between different wireless broadband access systems operating in the same unlicensed spectrum bands, and how to solve the coexistence problems via distributed coordination mechanisms. The problem of coexistence between different networks (i.e. LTE and Wi-Fi) and the problem of coexistence between different networks of the same technology (i.e. multiple Wi-Fi OBSSs) is analyzed both qualitatively and quantitatively via system-level simulations, and the main issues to be faced are identified from these results. From that, distributed coordination mechanisms are proposed and evaluated via system-level simulations, both for the inter-technology coexistence problem and intra-technology coexistence problem. Results indicate that the proposed solutions provide significant gains when compare to the situation without distributed coordination.

Variable 360° Vector-Sum Phase Shifter With Coarse and Fine Vector Scaling

A CMOS vector-sum phase shifter covering the full 360° range is presented in this paper. Broadband operational transconductance amplifiers with variable transconductance provide coarse scaling of the quadrature vector amplitudes. Fine scaling of the amplitudes is accomplished using a passive resistive network. Expressions are derived to predict the maximum bit resolution of the phase shifter from the scaling factor of the coarse and fine vector-scaling stages. The phase shifter was designed and fabricated using the standard 130-nm CMOS process and was tested on-wafer over the frequency range of 4.9–5.9 GHz. The phase shifter delivers root mean square (rms) phase and amplitude errors of 1.25° and 0.7 dB, respectively, at the midband frequency of 5.4 GHz. The input and output return losses are both below 17 dB over the band, and the insertion loss is better than 4 dB over the band. The circuit uses an area of 0.303 mm2 excluding bonding pads and draws 28 mW from a 1.2 V supply.

Joint Compensation of I/Q Impairments and PA Nonlinearity for Concurrent Dual-Band Transmitters using Two-Box Model

A novel two-box model for joint compensation of nonlinear distortion introduced from both in-phase/quadrature modulator and power amplifier is proposed for concurrent dual-band wireless transmitters. Compensation of nonlinear distortion is accomplished in two phases, where phases are identified separately. It is shown that complexity of the digital predistortion is reduced. The performance of the proposed model is evaluated in terms of ACPR, EVM and NMSE improvements using 1.4 MHz LTE and WCDMA signals.

Acceleration and visualization of Dynamic Network Optimization

With the emerging prevalence of smart phones and 4G LTE networks, the demand for faster-better-cheaper mobile services anytime and anywhere is ever growing. The Dynamic Network Optimization (DNO) concept emerged as a solution that optimally and continuously tunes the network settings, in response to varying network conditions and subscriber needs. Yet, the DNO realization is still at infancy, largely hindered by the bottleneck of the lengthy optimization runtime. This paper presents the design and prototype of a novel cloud based parallel solution that further enhances the scalability of our prior work on various parallel solutions that accelerate network optimization algorithms. The solution aims to satisfy the high performance required by DNO, preliminarily on a sub-hourly basis. The paper subsequently visualizes a design and a full cycle of a DNO system. A set of potential solutions to large network and real-time DNO are also proposed. Overall, this work creates a breakthrough towards the realization of DNO.

Weaving Futures. Family Transnationalism in the migration from Dominican Republic and Brazil to Spain

This article explores forms of migrant families’ reorganization within a (new) global economic crisis and the hardening of migration control in Europe; based on the cases of Dominican and Brazilian migration to Spain.Our goal is not to characterize the wholeness of strategies from these collectives, instead visualize its heterogeneity. Displacement of Dominican and Brazilian population to Spain shares the role of women as the first link of migration chains. In both cases women are the economic support of transnational families and they lead reunification's processes. Nevertheless, differences in the time spent in the destination country, migratory status, origin (rural-urban), level of education, class and labor insertion in destination country, affect differently, the planning and start up of migration projects, the organization of care and family reunification strategies. These findings question the predominant place granted to national origin in the study of international migration.

Modelos de modernización para el desarrollismo: el influjo de las propuestas estadounidenses en el Servicio de Extensión Agraria (1955-1975)

Con este trabajo nos proponemos estudiar las políticas agrarias del franquismo y particularmente la creación y actuación del Servicio de Extensión Agraria (1955) en el contexto de la difusión de la Teoría de la Modernización. Comenzaremos con una contextualización de las relaciones culturales entre España y los EE.UU. y su potencial proyección sobre el ámbito rural. A continuación, prestaremos atención a la impronta del modelo extensionista norteamericano en la organización y metodología del Servicio de Extensión Agraria. Sin perder de vista la importancia de la escala estatal para la implementación y adaptación de las distintas políticas agrarias, atenderemos al contexto político e ideológico internacional como elemento que permite ampliar la comprensión y estudio de dichas políticas. En ese sentido, propondremos finalmente una primera aproximación comparativa al estudio del SEA en relación con diferentes experiencias de extensionismo agrario en Latinoamérica.

Estados Unidos y la guerra por el desarrollo: el control de la natalidad en Chile, 1960-1970

Bajo el paradigma de modernización y desarrollo norteamericano -y en un contexto de Guerra Fría-, durante la década de 1960 se adecuaron a la realidad chilena programas de control de natalidad que no sólo buscaron disminuir las altas tasas de mortalidad materno infantil, sino que además respondieron al proyecto de seguridad hemisférica norteamericana de contención a posibles revoluciones populares en países del Tercer Mundo.

El Otro y el yo, las porras vs. el café: soluciones de traducción para los elementos culturales en las versiones castellanas de "Las baladas del ajo", de Mo Yan

El objetivo de este trabajo es mostrar los fenómenos en las traducciones de Las baladas del ajo, de texto original chino traducido primero al inglés, y del inglés al español. Asimismo, tenemos dos objetivos específicos, por un lado estudiamos las fórmulas de traducción de los elementos culturales –muy frecuentes– detectados en Las baladas del ajo y por el otro, observamos la traducción indirecta del inglés al español a través de una comparación entre el texto original en chino, la versión en inglés y la española. Las conclusiones de este trabajo nos permiten estudiar tanto las soluciones adoptadas para los elementos culturales, así como hacer una evaluación general de la traducción de segunda mano.

The VLT-FLAMES Tarantula Survey: XIX. B-type supergiants: Atmospheric parameters and nitrogen abundances to investigate the role of binarity and the width of the main sequence

Context: Model atmosphere analyses have been previously undertaken for both Galactic and extragalactic B-type supergiants. By contrast, little attention has been given to a comparison of the properties of single supergiants and those that are members of multiple systems. 

Aims: Atmospheric parameters and nitrogen abundances have been estimated for all the B-type supergiants identified in the VLT-FLAMES Tarantula survey. These include both single targets and binary candidates. The results have been analysed to investigate the role of binarity in the evolutionary history of supergiants. 

Methods: tlusty non-local thermodynamic equilibrium (LTE) model atmosphere calculations have been used to determine atmospheric parameters and nitrogen abundances for 34 single and 18 binary supergiants. Effective temperatures were deduced using the silicon balance technique, complemented by the helium ionisation in the hotter spectra. Surface gravities were estimated using Balmer line profiles and microturbulent velocities deduced using the silicon spectrum. Nitrogen abundances or upper limits were estimated from the Nii spectrum. The effects of a flux contribution from an unseen secondary were considered for the binary sample. Results. We present the first systematic study of the incidence of binarity for a sample of B-type supergiants across the theoretical terminal age main sequence (TAMS). To account for the distribution of effective temperatures of the B-type supergiants it may be necessary to extend the TAMS to lower temperatures. This is also consistent with the derived distribution of mass discrepancies, projected rotational velocities and nitrogen abundances, provided that stars cooler than this temperature are post-red supergiant objects. For all the supergiants in the Tarantula and in a previous FLAMES survey, the majority have small projected rotational velocities. The distribution peaks at about 50 km s^-1 with 65% in the range 30 km s^-1 ≤ ν_e sin i ≤ 60 km s^-1. About ten per cent have larger ve sin i (≥100 km s^-1), but surprisingly these show little or no nitrogen enhancement. All the cooler supergiants have low projected rotational velocities of ≤70 km s^-1 and high nitrogen abundance estimates, implying that either bi-stability braking or evolution on a blue loop may be important. Additionally, there is a lack of cooler binaries, possibly reflecting the small sample sizes. Single-star evolutionary models, which include rotation, can account for all of the nitrogen enhancement in both the single and binary samples. The detailed distribution of nitrogen abundances in the single and binary samples may be different, possibly reflecting differences in their evolutionary history. 

Conclusions: The first comparative study of single and binary B-type supergiants has revealed that the main sequence may be significantly wider than previously assumed, extending to T_eff = 20 000 K. Some marginal differences in single and binary atmospheric parameters and abundances have been identified, possibly implying non-standard evolution for some of the sample. This sample as a whole has implications for several aspects of our understanding of the evolutionary status of blue supergiants.

Dealing with flood damages: will prevention, mitigation, and ex post compensation provide for a resilient triangle?

There is a wealth of literature on the design of ex post compensation mechanisms for natural disasters. However, more research needs to be done on the manner in which these mechanisms could steer citizens toward adopting individual-level preventive and protection measures in the face of flood risks. We have provided a comparative legal analysis of the financial compensation mechanisms following floods, be it through insurance, public funds, or a combination of both, with an empirical focus on Belgium, the Netherlands, England, and France. Similarities and differences between the methods in which these compensation mechanisms for flood damages enhance resilience were analyzed. The comparative analysis especially focused on the link between the recovery strategy on the one hand and prevention and mitigation strategies on the other. There is great potential within the recovery strategy for promoting preventive action, for example in terms of discouraging citizens from living in high-risk areas, or encouraging the uptake of mitigation measures, such as adaptive building. However, this large potential has yet to be realized, in part because of insufficient consideration and promotion of these connections within existing legal frameworks. We have made recommendations about how the linkages between strategies can be further improved. These recommendations relate to, among others, the promotion of resilient reinstatement through recovery mechanisms and the removal of legal barriers preventing the establishment of link-inducing measures.

Educación postsecundaria en entorno universitario para alumnos con discapacidad intelectual: experiencias y resultados

El documento expone un exhaustivo análisis de los diferentes proyectos sobre enseñanza postsecundaria dirigida a jóvenes con discapacidad intelectual en el entorno universitario. En el libro se evalúa el impacto que la inclusión de jóvenes con discapacidad intelectual ha generado en el entorno universitario. En todos los casos se pone en valor la posibilidad de compartir espacios de formación, de socialización, de aprendizaje y crecimiento entre alumnos con y sin discapacidad y el enriquecimiento que tales situaciones comportan para todos.

Formalisation des connaissances pour le processus de développement de nouveaux produits

Nous avons élaboré comme objectif principal de cet essai la formalisation des connaissances lors du processus de développement de nouveaux produits qui pourra par la suite être intégrée dans un logiciel de système expert et implanté dans une entreprise de haute technologie. Suite à une revue de la littérature sur laquelle s'appuie le développement de cet essai, notre démarche pour formaliser les connaissances s'est effectuée par des entrevues semi-structurées pour étudier en détail le fonctionnement de l'entreprise lors du développement d'un nouveau produit. Après avoir identifier le modèle utilisé chez Systèmes d'Informatique Philips Ltée, nous avons déterminer les points précis dans le processus de développement d'un nouveau produit où sont prises les décisions, par qui ou par quel comité et à l'aide de quelles informations. Ceci a été suivi par l'identification de six phases dans leur modèle lors du développement de nouveaux produits. Nous avons par la suite formaliser les connaissances en des règles de production pour représenter ces six phases et tout ceci a été fait grâce à la collaboration des experts du département de marketing et de recherche et développement. Suite à ceci, nous avons étudiés divers projets de développement de nouveaux produits sur le marché (matériels et logiciels) afin d'ajouter d'autres règles à notre modèle. Pour mieux visualiser ces connaissances, nous avons développé un prototype de système expert avec le logiciel GURU, prototype qui représente les deux premières phases de notre modèle. Nous souhaitons que notre prototype de démonstration soit poursuivi jusqu'à l'implantation complète du système expert et ceci avec la possibilité de modifications liées à la vie de l'entreprise.

Plan estratégico para Mission Produce 2016-2020

Mission Produce es un productor, importador y distribuidor global de paltas Hass. Al 2015, la empresa tiene operaciones en México, Chile, Perú y los Estados Unidos. Más del 90% de las ventas de palta de Mission se realizan en los Estados Unidos y Canadá, el 6% en Japón y el resto en Europa, Singapur y China. En 2013, la empresa vendió el equivalente a un total de 176 mil toneladas a nivel mundial, siendo el 70% clientes minoritas, el 15% mayoristas, el 13% de servicios de alimentos y el 2% corredores, lo que le permitió obtener el 23% de la cuota del mercado. La oferta de los productos que Mission distribuye es 50% como palta dura, 36% como palta madura y el 16% empaquetada (frutas más pequeñas que se venden juntas en una red de nailon). Una orden federal de mercado en los Estados Unidos, aprobada en 2002, requiere que todos los vendedores de paltas Hass (nacionales e importadas) contribuyan con $ 0.055 centavos por cada kilo vendido. El Consejo del Palta Hass (HAB por sus siglas en inglés) administra los fondos y destina el 85% a las juntas estatales o juntas de importadores de palta para ser gastado en la promoción del producto. Los fondos de HAB también se utilizan para la investigación científica y del consumidor. Mission revolucionó la industria de paltas por ser la primera empresa en asegurar la entrega continua de fruta madura para los minoristas y las empresas de servicio de alimentos, mediante el desarrollo de una red de centros de maduración, diferentes modelos de adquisición de paltas y la integración vertical hacia atrás. En 2013, la empresa contaba con centros de maduración y distribución en ocho ciudades de los EE.UU. Mission decide comprar terrenos en el Perú y a principios del 2012 comenzó a transformar la zona desértica en uno de los mayores fundos de palta en el mundo. Lo más importante de los fundos en el Perú es que le otorgan en el mediano plazo el control total de la cadena de suministro. El consumo de paltas en EE.UU. al 2013 estaba en pleno auge, lo que generaba una escasez en la oferta global. Mission se había integrado verticalmente hacia atrás para ayudar a cerrar la brecha de la oferta, sin embargo, existían muchas otras oportunidades en el mercado. Dentro de las prioridades de Mission figura la adquisición de más tierras en Perú y otros cultivos de alto valor, como la uva y bayas. Otras interesantes alternativas son invertir en cultivos de paltas en otros países, diversificarse hacia el procesamiento, ampliar las actividades de su marketing internacional y construir la marca Mission en Europa y China.