Design of asymptotically optimal improper constellations with hexagonal packing

This paper addresses the problem of designing asymptotically optimal improper constellations with a given circularity coefficient (correlation coefficient between the constellation and its complex conjugate). The designed constellations are optimal in the sense that, at high signal-to-noise-ratio (SNR) and for a large number of symbols, yield the lowest probability of error under an average power constraint for additive white Gaussian noise channels. As the number of symbols grows, the optimal constellation is the intersection of the hexagonal lattice with an ellipse whose eccentricity determines the circularity coefficient. Based on this asymptotic result, we propose an algorithm to design finite improper constellations. The proposed constellations provide significant SNR gains with respect to previous improper designs, which were generated through a widely linear transformation of a standard M-ary quadrature amplitude modulation constellation. As an application example, we study the use of these improper constellations by a secondary user in an underlay cognitive radio network.The work of Jesús A. López-Fernández and R. G. Ayestarán was partly supported by the Ministerio de Ciencia, Innovación y Universidades under project TEC2017-86619-R (ARTEINE), and by the Gobierno del Principado de Asturias under project GRUPIN-IDI2018-000191. The work of I. Santamaria was partly supported by the Ministerio de Economía y Competitividad (MINECO) of Spain, and AEI/FEDER funds of the E.U., under grant TEC2016-75067-C4-4-R (CARMEN) and TEC2015-69648-REDC (Red COMONSENS). The work of C. Lameiro was supported by the German Research Foundation (DFG) under grant LA 4107/1-1

Sentidos de la Planeación del Desarrollo Local y el Presupuesto Participativo. Vivencias en las comunas 1 (Popular) y 8 (Villa Hermosa) de Medellín, 2004-2011

RESUMEN: Planeación Local y Presupuesto Participativo, individual y conjuntamente considerados, son opciones potentes para favorecer la construcción del territorio. Asimismo, para motivar e incentivar la lucha por alcanzar individual y colectivamente la categoría de ciudadano, ejercer múltiples y diversas ciudadanías. Igualmente, servirán para contribuir al fortalecimiento de la sociedad civil y la consolidación de estructuras gubernamentales del Estado que se encaminen, al unísono, hacia la construcción de un auténtico proyecto político democrático participativo. Ambos, como escenarios de oportunidades democráticas, específicamente en la vivencia de Medellín, se debaten en medio de las confluencias perversas democráticas y neoliberales, junto a la diversidad de enfoques vigente en materia de democracia participativa, participación democrática y ciudadana, PDLPP

Aerodynamic optimization of propellers for High Altitude Pseudo-Satellites

[EN] The propulsion system of High-Altitude Platform Stations or High-Altitude Pseudo-Satellites (HAPS) is commonly based on propellers. The properties of the atmosphere at those high altitudes and the characteristic speed of HAPS entail that the flight is performed at very low Reynolds numbers. Hence, the aerodynamic behavior of the propeller sections changes substantially from the hub to the tip of the blades. Under those circumstances, the ordinary methods to develop optimized propellers are not useful and must be modified. We present a method of propeller design adapted to HAPS features. It combines traditional solutions with modern numerical tools. Specifically, Theodorsen analytical theory is used to minimize induced drag. This process leaves one free parameter that it is fixed optimizing a cost function depending on the Reynolds number with a viscous-potential numerical code. It leads to an optimal determination of the geometrical characteristics of the propeller, i.e., chord and pitch distribution, increasing its total efficiency. The resulting algorithm has low computational requirements what makes it very appropriate for the preliminary design of HAPS missions, when it is necessary to simulate many different cases. That methodology has been applied to a relatively small HAPS airship with a wind speed of 10 m/s and required thrust of 100 N. The propeller is assumed to be made up of NACA4412 airfoils and the cost function to be minimized is given by the ratio of the 2D drag and lift coefficients. With those conditions we perform a parametric analysis where different combinations of diameters, thrust coefficients, and propeller advance ratios are considered. Over a Reynolds number range from 103 to 106, the new method provides a gain about 5% in the propeller efficiency when compared with the ordinary design procedure that employs a constant Reynolds number. That gain is of utmost importance for HAPS operations, since, for example, it allows an increase in the payload of up to 25% for a 90 meters long airship.S

On the capabilities and limitations of high altitude pseudo-satellites

[EN] The idea of self-sustaining air vehicles that excited engineers in the seventies has nowadays become a reality as proved by several initiatives worldwide. High altitude platforms, or Pseudo-satellites (HAPS), are unmanned vehicles that take advantage of weak stratospheric winds and solar energy to operate without interfering with current commercial aviation and with enough endurance to provide long-term services as satellites do. Target applications are communications, Earth observation, positioning and science among others. This paper reviews the major characteristics of stratospheric flight, where airplanes and airships will compete for best performance. The careful analysis of involved technologies and their trends allow budget models to shed light on the capabilities and limitations of each solution. Aerodynamics and aerostatics, structures and materials, propulsion, energy management, thermal control, flight management and ground infrastructures are the critical elements revisited to assess current status and expected short-term evolutions. Stratospheric airplanes require very light wing loading, which has been demonstrated to be feasible but currently limits their payload mass to few tenths of kilograms. On the other hand, airships need to be large and operationally complex but their potential to hover carrying hundreds of kilograms with reasonable power supply make them true pseudo-satellites with enormous commercial interest. This paper provides useful information on the relative importance of the technology evolutions, as well as on the selection of the proper platform for each application or set of payload requirements. The authors envisage prompt availability of both types of HAPS, aerodynamic and aerostatic, providing unprecedented services.SIEuropean Space Agenc

Design and implementation of a cloud-based platform for unleashing the personal and communal Internet of Things

Internet of Things (IoT) concept has attracted a lot of attention in recent years and it is foreseen as one of the technologies that will leverage the Future Internet. It is seen as a major enabler of novel applications and services that will foster efficiency and will ease every day´s life. However, current IoT solutions are mainly focusing on the development of centralized solutions that do not promote the democratization of the IoT but rather concentrate the IoT around a set of cloud-based platforms which pretend to be open but limit the capacity of the people to tailor their Personal and Communal IoT. This paper describes a software platform based on available generic enablers as defined by the FIWARE initiative. It extends the existing architecture models to accommodate the requirements stemming from the vision of people-sourced IoT devices which are shared to create applications and services in smart communities where the owners of the shared devices are always empowered to control who, and in which circumstances, has access to the shared information.This work has been partially funded by the research project SOCIOTAL, under FP7-ICT-2013.1.4 (ref. 609112) of the 7th Framework Programme of the European Community. This work has been also supported by the Spanish Government (Ministerio de Economía y Competitividad, Fondo Europeo de Desarrollo Regional, FEDER) by means of the project ADVICE “Dynamic Provisioning of Connectivity in High Density 5G Wireless Scenarios” (TEC2015-71329-C2-1-R)

Estudio dinámico de la movilidad escolar mediante tecnologías web de geolocalización

[ES] Los desplazamientos realizados a los centros de enseñanza son unos de los comportamientos de movilidad más sensibles debido a la vulnerabilidad de sus principales protagonistas: los niños, y su interacción con otros tipos de usuarios. Además, la temporalidad de estos movimientos es un factor de alto impacto, pues provoca problemas puntuales de congestión en zonas próximas a los colegios en las horas concretas de entrada y salida, por lo que se generan conflictos en la circulación, poniendo en riesgo a usuarios, y a conductores y peatones del entorno. El domicilio habitual de los alumnos y sus modos de desplazamiento hasta el centro educativo, serán datos fundamentales para poder establecer políticas adecuadas de movilidad en cada uno de los centros. Y para poder formular acciones conjuntas en esta materia sobre una región, se requiere conocer con rigurosidad, y de una forma global, el problema existente en un gran número de centros. En este trabajo se desarrolla una investigación sobre seguridad vial en entornos escolares, basada en las nuevas tecnologías de información y comunicación, desarrollando y aplicando técnicas de geolocalización a través de Internet, que permiten relacionar datos sobre el comportamiento de los usuarios de los viales, con las localizaciones del origen y destino de los desplazamientos. De esta manera se dispone de información desagregada de gran interés para analizar sobre Sistemas de Información Geográfica (SIG), estudiando rutas óptimas desde domicilios a centros educativos, viales empleados, longitudes de recorridos, características de los desplazamientos, adecuación de infraestructuras, modos y servicios de transporte, etc., con lo que se elabora un complejo informe estadístico sobre la movilidad escolar. Este trabajo cuenta con una subvención de la DGT para el desarrollo de proyectos de investigación en el área de tráfico, movilidad y seguridad vial correspondientes a 2015.Este artículo se encuadra dentro del proyecto titulado ESTUDIO DINÁMICO DE LA MOVILIDAD ESCOLAR MEDIANTE TECNOLOGÍAS WEB DE GEOLOCALIZACIÓN y que ha sido subvencionado, con la referencia SPIP2015-01867, mediante Resolución de 24 de noviembre de 2015 de la Dirección General de Tráfico, por la que se resuelve la convocatoria de subvenciones destinadas al desarrollo de proyectos de investigación en el área de tráfico, movilidad y seguridad vial, correspondientes al ejercicio 2015, convocatoria efectuada por Resolución de 1 de julio de 2015, de la Dirección General de Tráfico (B.O.E. núm. 160, de 6 de julio).Varela-García, F.; Hernández Ibañez, L.; Novales Ordax, M.; Orro Arcay, A.; Gutiérrez Puebla, J.; López Fernandez, J. (2016). Estudio dinámico de la movilidad escolar mediante tecnologías web de geolocalización. En XII Congreso de ingeniería del transporte. 7, 8 y 9 de Junio, Valencia (España). Editorial Universitat Politècnica de València. 2001-2010. https://doi.org/10.4995/CIT2016.2016.4107OCS2001201

Prácticas de Biomecánica de la Actividad Física y del Deporte: bike-fit básico.

[ES] Actualmente, la biomecánica deportiva facilita al profesional en Ciencias de la Actividad Física y del Deporte indicaciones precisas sobre cómo ajustar una bicicleta de forma óptima. En esta práctica, aprenderás a realizar un ajuste (bike-fit) básico, que podrás utilizar en diversos ámbitos de tu desempeño profesional

Prácticas de Biomecánica de la Actividad Física y del Deporte: Análisis biomecánico de la carrera de larga distancia

La carrera a pie es una de las actividades deportivas más antiguas de las que se tiene constancia y una de las escasas pruebas que componían los Juegos Olímpicos de la antigüedad. Hasta mediados del siglo XX, su práctica se manifestó fundamentalmente en un ámbito competitivo. A partir de entonces, también comenzó a desarrollarse a nivel recreativo, aumentando su popularidad progresivamente hasta el punto de que, hoy en día, millones de personas la practican a nivel global, cubriendo distancias desde los 5 km a la maratón (Scheerder et al., 2015

Naturally occurring deamidated triosephosphate isomerase is a promising target for cell-selective therapy in cancer

Human triosephosphate isomerase (HsTIM) is a central glycolytic enzyme and is overexpressed in cancer cells with accelerated glycolysis. Triple-negative breast cancer is highly dependent on glycolysis and is typically treated with a combination of surgery, radiation therapy, and chemotherapy. Deamidated HsTIM was recently proposed as a druggable target. Although thiol-reactive drugs affect cell growth in deamidated HsTIM-complemented cells, the role of this protein as a selective target has not been demonstrated. To delve into the usefulness of deamidated HsTIM as a selective target, we assessed its natural accumulation in breast cancer cells. We found that deamidated HsTIM accumulates in breast cancer cells but not in noncancerous cells. The cancer cells are selectively programmed to undergo cell death with thiol-reactive drugs that induced the production of methylglyoxal (MGO) and advanced glycation-end products (AGEs). In vivo, a thiol-reactive drug effectively inhibits the growth of xenograft tumors with an underlying mechanism involving deamidated HsTIM. Our findings demonstrate the usefulness of deamidated HsTIM as target to develop new therapeutic strategies for the treatment of cancers and other pathologies in which this post translationally modified protein accumulates

Incidence of Tuberculosis Among Young Children in Rural Mozambique

BACKGROUND: Tuberculosis (TB) contributes significantly to child morbidity and mortality. This study aimed to estimate the minimum community-based incidence rate of TB among children <3 years of age in Southern Mozambique. METHODS: Between October 2011 and October 2012, in the Manhica District Health and Demographic Surveillance System, we enrolled prospectively all presumptive TB cases younger than 3 years of age through passive and active case finding. Participants included all children who were either symptomatic or were close contacts of a notified adult smear-positive pulmonary TB. Children were clinically evaluated at baseline and follow-up visits. Investigation for TB disease included chest radiography, HIV and tuberculin skin testing as well as gastric aspirate and induced sputum sampling, which were processed for smear, culture and mycobacterial molecular identification. RESULTS: During the study period, 13,764 children <3 years contributed to a total of 9575 person-year. Out of the 789 presumptive TB cases enrolled, 13 had TB culture confirmation and 32 were probable TB cases. The minimum community-based incidence rate of TB (confirmed plus probable cases) was 470 of 100,000 person-year (95% confidence interval: 343-629 of 100,000). HIV co-infection was present in 44% of the TB cases. CONCLUSION: These data highlight the huge burden of pediatric TB. This study provides one of the first prospective population-based incidence data of childhood tuberculosis and adds valuable information to the global effort of producing better estimates, a critical step to inform public health policy