27 research outputs found
Cryptographic functions in a smart card
Bustos Rodríguez, AJ. (2010). Cryptographic functions in a smart card. http://hdl.handle.net/10251/10194.Archivo delegad
Improving The Fault Tolerance of Ad Hoc Routing Protocols using Aspect-oriented Programming
[ES] Las redes ad hoc son redes inalámbricas distribuidas formadas por nodos móviles que se ubican
libremente y dinámicamente, capaces de organizarse de manera propia en topologías arbitrarias y
temporales, a través de la actuación de los protocolos de encaminamiento. Estas redes permiten a las
personas y dispositivos conectarse sin problemas rápidamente, en áreas sin una infraestructura de
comunicaciones previa y con un bajo coste. Muchos estudios demuestran que los protocolos de
encaminamiento ad hoc se ven amenazados por una variedad de fallos accidentales y maliciosos, como
la saturación de vecinos, que puede afectar a cualquier tipo de red ad hoc, y el ruido ambiental, que
puede afectar en general a todas las redes inalámbricas. Por lo tanto, el desarrollo y la implementación
de estrategias de tolerancia a fallos para mitigar el efecto de las fallos, es esencial para el uso práctico
de este tipo de redes. Sin embargo, los mecanismos de tolerancia a fallos suelen estar implementados
de manera específica, dentro del código fuente de los protocolos de encaminamiento que hace que i)
ser reescrito y reorganizado cada vez que una nueva versión de un protocolo se libera, y ii) tener un
carácter completamente remodelado y adaptado a las nuevas versiones de los protocolos. Esta tesis de
máster explora la viabilidad de utilizar programación orientada a aspectos (AOP), para desarrollar e
implementar los mecanismos de tolerancia a fallos adecuados para toda una familia de protocolos de
encaminamiento, es decir, las versiones actuales y futuras de un protocolo determinado (OLSR en este
caso). Por otra parte, se propone una nueva metodología para ampliar estos mecanismos a diferentes
familias de protocolos proactivos (OLSR, BATMAN y Babel) con un nuevo concepto de AOP, el metaaspecto.
La viabilidad y efectividad de la propuesta se ha evaluado experimentalmente, estableciendo
así un nuevo método para mejorar la implementación de la portabilidad y facilidad de mantenimiento
de los mecanismos de tolerancia a fallos en los protocolos de enrutamiento ad hoc y, por lo tanto, la
fiabilidad de las redes ad hoc.[EN] Ad hoc networks are distributed networks consisting of wireless mobile nodes that can freely and
dynamically self-organize into arbitrary and temporary topologies, through the operation of routing
protocols. These networks allow people and devices to seamlessly interconnect rapidly in areas with no
pre-existing communication infrastructure and with a low cost. Many studies show that ad hoc routing
protocols are threatened by a variety of accidental and malicious faults, like neighbour saturation,
which may affect any kind of ad hoc network, and ambient noise, which may impact all wireless
networks in general. Therefore, developing and deploying fault tolerance strategies to mitigate the
effect of such faults is essential for the practical use of this kind of networks. However, those fault
tolerance mechanisms are usually embedded into the source code of routing protocols which causes
that i) they must be rewritten and redeployed whenever a new version of a protocol is released, and ii)
they must be completely redeveloped and adapted to new routing protocols. This master thesis
explores the feasibility of using Aspect-Oriented Programming (AOP) to develop and deploy fault
tolerance mechanisms suitable for a whole family of routing protocols, i.e. existing and future versions
of a given protocol (OLSR in this case). Furthermore, a new methodology is proposed to extend these
mechanisms to different families of proactive protocols (OLSR, B.A.T.M.A.N and Babel) using a new
concept in AOP, the meta-aspect. The feasibility and effectiveness of the proposal is experimentally
assessed, thus establishing a new method to improve the deployment, portability, and maintainability
of fault tolerance mechanisms for ad hoc routing protocols and, therefore, the dependability of ad hoc
networks.Bustos Rodríguez, AJ. (2012). Improving The Fault Tolerance of Ad Hoc Routing Protocols using Aspect-oriented Programming. http://hdl.handle.net/10251/18421Archivo delegad
Ambient noise in wireless mesh networks: Evaluation and proposal of an adaptive algorithm to mitigate link removal
[EN] Ambient noise is one of the major problems in Wireless Mesh Networks (WMNs). It is responsible for adverse effects on communications such as packet dropping, which dramatically affects the behaviour of
ad hoc routing protocols ,a key element of these networks. This issue is of prime importance for WMNs
since the loss of communication links experienced by nodes may strongly increase the convergence time
of the network. Furthermore, the dynamic nature of this problem makes it difficult to address with
traditional techniques. The contribution of this paper goes in the direction of (i) exploring this problem
by assessing the behaviour of three state-of-the-art routing protocols in the presence of ambient noise
(OLSR, B.A.T.M.A.N and Babel) and (ii) improving the resilience capabilities of these protocols against
ambient noise by proposing an algorithm for the link quality-based adaptive replication of packets,
named LARK. The goal of LARK is to avoid the loss of communication links in the presence of high levels
of ambient noise. The effectiveness of the proposal is experimentally assessed, thus establishing a new
method to reduce the impact of ambient noise on WMNs.This work is partially supported by the Spanish projects ARENES (TIN2012-38308-C02-01) and SEMSECAP (TIN-2009-13825), the ANR French project AMORES (ANR-11-INSE-010), and the Intel Doctoral Student Honour Programme 2012.Friginal López, J.; Ruiz García, JC.; Andrés Martínez, DD.; Bustos Rodríguez, A. (2014). Ambient noise in wireless mesh networks: Evaluation and proposal of an adaptive algorithm to mitigate link removal. Journal of Network and Computer Applications. 41:505-516. https://doi.org/10.1016/j.jnca.2014.02.004S5055164
Structural, Magnetic and Mechanical Properties of Nd16 (Fe76−xCox)B8 0 ≤ x ≤ 25 Alloys
In this work, the structural, magnetic and mechanical properties of Nd16Fe76−xCoxB8 alloys with a varying Co content of x = 0, 10, 20 and 25 were experimentally investigated by X-ray diffraction (XRD), Mössbauer spectrometry (MS) and vibrating sample magnetometry (VSM) at room temperature (RT), and microhardness tests were performed. The system presented hard Nd2Fe14B and the Nd1.1Fe4B4 phases for samples with x = 0; when the concentration increased to x = 20 and 25, the CoO phase appeared. All MS data showed ferromagnetic behavior (eight sextets: sites 16k1, 16k2, 8j1, 8j2, 4c, 4e, sb) associated with the hard and soft magnetic phases, and one paramagnetic component (doublet: site d) associated with the minority Nd1.1Fe4B4 phase, which was not identified by XRD. All samples were magnetically hard and presented hard magnetic behavior. The increase of Co content in these samples did not improve the hard magnetic properties but increased the critical temperature of the system and decreased the crystallite size of the hard phase. There was a general tendency towards increased microhardness with cobalt content that was attributable to cobalt doping, which reduces the lattice parameters and porosities within the sample, improving its hardness
Metabolic and Functional Improvements in a Patient with Charcot-Marie-Tooth Disease Type 2 after EGCG Administration: A Case Report
Background and objectives: The aim of this study was to report a case of a patient with Charcot-Marie-Tooth disease type 2 (CMT2) treated with epigallocatechin gallate (EGCG) for 4 months in order to assess its therapeutic potential in CMT2. Materials and Methods: The study included a brother and a sister who have CMT2. The sister received 800 mg of EGCG for 4 months, while her brother received placebo for the same period of time. Both participants were assessed before and after daily administration by means of anthropometry; analysis of inflammatory and oxidation markers of interleukin-6 (IL-6) and paraoxonase 1 (PON1) in the blood sample; and motor tests: 2-min walk test (2MWT), 10-m walk test (10MWT), nine-hole peg test (9HPT) and handgrip strength measurement using a handheld Jamar dynamometer. Results: Regarding muscular and motor functions associated with higher inflammation and oxidation, improvements only observed in the woman in all analysed parameters (both biochemical and clinical associated with the metabolism and functionality) after 4 months of treatment with EGCG are noteworthy. Thus, this treatment is proposed as a good candidate to treat the disease
Las actividades de Vigilancia Atmosférica Global (VAG) del Centro de Investigación Atmosférica de Izaña
Ponencia presentada en: XXXIII Jornadas Científicas de la AME y el XIV Encuentro Hispano Luso de Meteorología celebrado en Oviedo, del 7 al 9 de abril de 2014
Izaña Atmospheric Research Center. Activity Report 2019-2020
Editors: Emilio Cuevas, Celia Milford and Oksana Tarasova.[EN]The Izaña Atmospheric Research Center (IARC), which is part of the State Meteorological Agency of Spain (AEMET), is a site of excellence in atmospheric science. It manages four observatories in Tenerife including the high altitude Izaña Atmospheric Observatory. The Izaña Atmospheric Observatory was inaugurated in 1916 and since that date has carried out uninterrupted meteorological and climatological observations, contributing towards a unique 100-year record in 2016.
This reports are a summary of the many activities at the Izaña Atmospheric Research Center to the broader community. The combination of operational activities, research and development in state-of-the-art measurement techniques, calibration and validation and international cooperation encompass the vision of WMO to provide world leadership in expertise and international cooperation in weather, climate, hydrology and related environmental issues.[ES]El Centro de Investigación Atmosférica de Izaña (CIAI), que forma parte de la Agencia Estatal de Meteorología de España (AEMET), representa un centro de excelencia en ciencias atmosféricas. Gestiona cuatro observatorios en Tenerife, incluido el Observatorio de Izaña de gran altitud, inaugurado en 1916 y que desde entonces ha realizado observaciones meteorológicas y climatológicas ininterrumpidas y se ha convertido en una estación centenaria de la OMM.
Estos informes resumen las múltiples actividades llevadas a cabo por el Centro de Investigación Atmosférica de Izaña. El liderazgo del Centro en materia de investigación y desarrollo con respecto a las técnicas de medición, calibración y validación de última generación, así como la cooperación internacional, le han otorgado una reputación sobresaliente en lo que se refiere al tiempo, el clima, la hidrología y otros temas ambientales afines
Izaña Atmospheric Research Center. Activity Report 2015-2016
This report is a summary of the many activities at the Izaña Atmospheric Research Center to the broader community. The combination of operational activities, research and development in state-of-the-art measurement techniques, calibration and validation and international cooperation encompass the vision of WMO to provide world leadership in expertise and international cooperation in weather, climate, hydrology and related environmental issues