QoSatAr: a cross-layer architecture for E2E QoS provisioning over DVB-S2 broadband satellite systems

This article presents QoSatAr, a cross-layer architecture developed to provide end-to-end quality of service (QoS) guarantees for Internet protocol (IP) traffic over the Digital Video Broadcasting-Second generation (DVB-S2) satellite systems. The architecture design is based on a cross-layer optimization between the physical layer and the network layer to provide QoS provisioning based on the bandwidth availability present in the DVB-S2 satellite channel. Our design is developed at the satellite-independent layers, being in compliance with the ETSI-BSM-QoS standards. The architecture is set up inside the gateway, it includes a Re-Queuing Mechanism (RQM) to enhance the goodput of the EF and AF traffic classes and an adaptive IP scheduler to guarantee the high-priority traffic classes taking into account the channel conditions affected by rain events. One of the most important aspect of the architecture design is that QoSatAr is able to guarantee the QoS requirements for specific traffic flows considering a single parameter: the bandwidth availability which is set at the physical layer (considering adaptive code and modulation adaptation) and sent to the network layer by means of a cross-layer optimization. The architecture has been evaluated using the NS-2 simulator. In this article, we present evaluation metrics, extensive simulations results and conclusions about the performance of the proposed QoSatAr when it is evaluated over a DVB-S2 satellite scenario. The key results show that the implementation of this architecture enables to keep control of the satellite system load while guaranteeing the QoS levels for the high-priority traffic classes even when bandwidth variations due to rain events are experienced. Moreover, using the RQM mechanism the user’s quality of experience is improved while keeping lower delay and jitter values for the high-priority traffic classes. In particular, the AF goodput is enhanced around 33% over the drop tail scheme (on average)

Comunicación corta. Diferenciación de cepas vacunales del virus del síndrome reproductor y respiratorio porcino de tipo I y cepas de campo por análisis de polimorfismos en la longitud de fragmentos de restricción

The use of modified live virus (MLV) vaccines is a common procedure to control porcine reproductive and respiratory syndrome virus (PRRSV) infection in the great majority of countries from America, Asia and Europe, including Spain. Current discriminatory techniques allow the detection of different MLV type-II vaccine strains. Herein we report a rapid and accurate technique aimed to discriminate between MLV type-I vaccine strains and Spanish field strains. This technique comprises a reverse transcription (RT) and nested polymerase chain reaction (nPCR) amplification of PRRSV ORF5 followed by a digestion of RT-nPCR products with two specific endonucleases, ItaI and AccI. Combined utilization of ItaI and AccI generates restriction fragments length polymorphisms (RFLP) patterns adequate for the differentiation of 30 Spanish field isolates, of which 12 were isolated between 1991 and 1995 and 18 between 2000 and 2003. These different RFLP patterns can be used to distinguish unequivocally between Spanish field strains of PRRSV and the three MLV type-I vaccines used in Spain: AmervacPRRS®, Pyrsvac-183® and PorcilisPRRS®.Para controlar la infección por el virus del síndrome reproductor y respiratorio porcino (PRRSV), en la gran mayoría de países de América, Asia y Europa, incluyendo España, se usan frecuentemente vacunas basadas en virus vivos modificados (MLV). En la actualidad existen técnicas discriminatorias que permiten detectar cepas vacunales del PRRSV de tipo II. El presente trabajo describe una técnica precisa y rápida para la diferenciación de cepas vacunales de tipo I del PRRSV y cepas de campo españolas. Esta técnica se basa en la transcripción reversa y posterior amplificación de la ORF5 del genoma del PRRSV utilizando la reacción en cadena de la polimerasa anidada, seguida de la digestión de los amplicones generados con dos endonucleasas específicas: ItaI y AccI. La utilización combinada de ambas enzimas genera patrones de polimorfismos en la longitud de fragmentos de restricción (RFLP), adecuados para la distinción de las 30 cepas de campo usadas, de las cuales 12 fueron aisladas entre 1991 y 1995 y 18 entre 2000 y 2003. Estos diferentes patrones pueden ser utilizados para distinguir entre cepas de campo españolas del PRRSV y las tres cepas vacunales de tipo I usadas en España: AmervacPRRS®, Pyrsvac-183® y PorcilisPRRS®

Energy System Planning towards Renewable Power System: Energy Matrix Change in Cuba by 2030

Since 2013, the biggest Caribbean island, Cuba, has been undertaking an energy matrix change. There is a strong political intention to replace fossil fuels by renewable energy and improve efficiency and security of the national energy system. By 2030, 24% of electric power shall be produced from renewable sources. Transition from centralized fossil fuel fired power system towards distributed renewable generation based system requires changes to conventional energy planning and system design procedures as well as physical structures of the national energy system. This paper introduces three analysis axis: Scenario building for future supply-demand balance, scenario for a 100% renewable energy system for Cuba, and a roadmap from existing power system to the system with high share of distributed renewable generation. This work is a part of European Union funded Erasmus+ project "Capacity Building for Renewable Energy Planning in Cuban Higher Education Institutions", CRECE.<br /