Design and Implementation of a Communication Protocol to Improve Multimedia QoS and QoE in Wireless Ad Hoc Networks

[EN] This dissertation addresses the problem of multimedia delivery over multi-hop ad hoc wireless networks, and especially over wireless sensor networks. Due to their characteristics of low power consumption, low processing capacity and low memory capacity, they have major difficulties in achieving optimal quality levels demanded by end users in such communications. In the first part of this work, it has been carried out a study to determine the behavior of a variety of multimedia streams and how they are affected by the network conditions when they are transmitted over topologies formed by devices of different technologies in multi hop wireless ad hoc mode. To achieve this goal, we have performed experimental tests using a test bench, which combine the main codecs used in audio and video streaming over IP networks with different sound and video captures representing the characteristic patterns of multimedia services such as phone calls, video communications, IPTV and video on demand (VOD). With the information gathered in the laboratory, we have been able to establish the correlation between the induced changes in the physical and logical topology and the network parameters that measure the quality of service (QoS) of a multimedia transmission, such as latency, jitter or packet loss. At this stage of the investigation, a study was performed to determine the state of the art of the proposed protocols, algorithms, and practical implementations that have been explicitly developed to optimize the multimedia transmission over wireless ad hoc networks, especially in ad hoc networks using clusters of nodes distributed over a geographic area and wireless sensor networks. Next step of this research was the development of an algorithm focused on the logical organization of clusters formed by nodes capable of adapting to the circumstances of real-time traffic. The stated goal was to achieve the maximum utilization of the resources offered by the set of nodes that forms the network, allowing simultaneously sending reliably and efficiently all types of content through them, and mixing conventional IP data traffic with multimedia traffic with stringent QoS and QoE requirements. Using the information gathered in the previous phase, we have developed a network architecture that improves overall network performance and multimedia streaming. In parallel, it has been designed and programmed a communication protocol that allows implementing the proposal and testing its operation on real network infrastructures. In the last phase of this thesis we have focused our work on sending multimedia in wireless sensor networks (WSN). Based on the above results, we have adapted both the architecture and the communication protocol for this particular type of network, whose use has been growing hugely in recent years.[ES] Esta tesis doctoral aborda el problema de la distribución de contenidos multimedia a través de redes inalámbricas ad hoc multisalto, especialmente las redes inalámbricas de sensores que, debido a sus características de bajo consumo energético, baja capacidad de procesamiento y baja capacidad de memoria, plantean grandes dificultades para alcanzar los niveles de calidad óptimos que exigen los usuarios finales en dicho tipo de comunicaciones. En la primera parte de este trabajo se ha llevado a cabo un estudio para determinar el comportamiento de una gran variedad de flujos multimedia y como se ven afectados por las condiciones de la red cuando son transmitidos a través topologías formadas por dispositivos de diferentes tecnologías que se comunican en modo ad hoc multisalto inalámbrico. Para ello, se han realizado pruebas experimentales sobre una maqueta de laboratorio, combinando los principales códecs empleados en la transmisión de audio y video a través de redes IP con diversas capturas de sonido y video que representan patrones característicos de servicios multimedia tales como las llamadas telefónicas, videoconferencias, IPTV o video bajo demanda (VOD). Con la información reunida en el laboratorio se ha podido establecer la correlación entre los cambios inducidos en la topología física y lógica de la red con los parámetros que miden la calidad de servicio (QoS) de una transmisión multimedia, tales como la latencia el jitter o la pérdida de paquetes. En esta fase de la investigación se realiza un estudio para determinar el estado del arte de las propuestas de desarrollo e implementación de protocolos y algoritmos que se han generado de forma explícita para optimizar la transmisión de tráfico multimedia sobre redes ad hoc inalámbricas, especialmente en las redes inalámbricas de sensores y redes ad hoc utilizando clústeres de nodos distribuidos en un espacio geográfico. El siguiente paso en la investigación ha consistido en el desarrollo de un algoritmo propio para la organización lógica de clústeres formados por nodos capaces de adaptarse a las circunstancias del tráfico en tiempo real. El objetivo planteado es conseguir un aprovechamiento máximo de los recursos ofrecidos por el conjunto de nodos que forman la red, permitiendo de forma simultánea el envío de todo tipo de contenidos a través de ellos de forma confiable y eficiente, permitiendo la convivencia de tráfico de datos IP convencional con tráfico multimedia con requisitos exigentes de QoS y QoE. A partir de la información conseguida en la fase anterior, se ha desarrollado una arquitectura de red que mejora el rendimiento general de la red y el de las transmisiones multimedia de audio y video en particular. De forma paralela, se ha diseñado y programado un protocolo de comunicación que permite implementar el modelo y testear su funcionamiento sobre infraestructuras de red reales. En la última fase de esta tesis se ha dirigido la atención hacia la transmisión multimedia en las redes de sensores inalámbricos (WSN). Partiendo de los resultados anteriores, se ha adaptado tanto la arquitectura como el protocolo de comunicaciones para este tipo concreto de red, cuyo uso se ha extendido en los últimos años de forma considerable[CA] Esta tesi doctoral aborda el problema de la distribució de continguts multimèdia a través de xarxes sense fil ad hoc multi salt, especialment les xarxes sense fil de sensors que, a causa de les seues característiques de baix consum energètic, baixa capacitat de processament i baixa capacitat de memòria, plantegen grans dificultats per a aconseguir els nivells de qualitat òptims que exigixen els usuaris finals en eixos tipus de comunicacions. En la primera part d'este treball s'ha dut a terme un estudi per a determinar el comportament d'una gran varietat de fluxos multimèdia i com es veuen afectats per les condicions de la xarxa quan són transmesos a través topologies formades per dispositius de diferents tecnologies que es comuniquen en mode ad hoc multi salt sense fil. Per a això, s'han realitzat proves experimentals sobre una maqueta de laboratori, combinant els principals códecs empleats en la transmissió d'àudio i vídeo a través de xarxes IP amb diverses captures de so i vídeo que representen patrons característics de serveis multimèdia com son les cridades telefòniques, videoconferències, IPTV o vídeo baix demanda (VOD). Amb la informació reunida en el laboratori s'ha pogut establir la correlació entre els canvis induïts en la topologia física i lògica de la xarxa amb els paràmetres que mesuren la qualitat de servei (QoS) d'una transmissió multimèdia, com la latència el jitter o la pèrdua de paquets. En esta fase de la investigació es realitza un estudi per a determinar l'estat de l'art de les propostes de desenvolupament i implementació de protocols i algoritmes que s'han generat de forma explícita per a optimitzar la transmissió de tràfic multimèdia sobre xarxes ad hoc sense fil, especialment en les xarxes sense fil de sensors and xarxes ad hoc utilitzant clusters de nodes distribuïts en un espai geogràfic. El següent pas en la investigació ha consistit en el desenvolupament d'un algoritme propi per a l'organització lògica de clusters formats per nodes capaços d'adaptar-se a les circumstàncies del tràfic en temps real. L'objectiu plantejat és aconseguir un aprofitament màxim dels recursos oferits pel conjunt de nodes que formen la xarxa, permetent de forma simultània l'enviament de qualsevol tipus de continguts a través d'ells de forma confiable i eficient, permetent la convivència de tràfic de dades IP convencional amb tràfic multimèdia amb requisits exigents de QoS i QoE. A partir de la informació aconseguida en la fase anterior, s'ha desenvolupat una arquitectura de xarxa que millora el rendiment general de la xarxa i el de les transmissions multimèdia d'àudio i vídeo en particular. De forma paral¿lela, s'ha dissenyat i programat un protocol de comunicació que permet implementar el model i testejar el seu funcionament sobre infraestructures de xarxa reals. En l'última fase d'esta tesi s'ha dirigit l'atenció cap a la transmissió multimèdia en les xarxes de sensors sense fil (WSN). Partint dels resultats anteriors, s'ha adaptat tant l'arquitectura com el protocol de comunicacions per a aquest tipus concret de xarxa, l'ús del qual s'ha estés en els últims anys de forma considerable.Díaz Santos, JR. (2016). Design and Implementation of a Communication Protocol to Improve Multimedia QoS and QoE in Wireless Ad Hoc Networks [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/62162TESI

Test bench to test protocols and algorithms for multimedia delivery

Nowadays, the study of Quality of Service (QoS) in multimedia streaming is generally carried out by simulators. However, the results of these tests are not quite real. This forces researchers to work with approximations. In this paper, we implement a test bench to test the performance and assess the protocols and algorithms for multimedia delivery. This test bench let us evaluate the network parameters performance, by manipulating the devices under controlled conditions, and allow us to identify different application cases. We can confirm that the designed test bench gives us more real measures than a simulators, which allows us to do many types of tests with low cost.Jimenez, JM.; Lloret, J.; Díaz Santos, JR.; Lacuesta Gilaberte, R. (2017). Test bench to test protocols and algorithms for multimedia delivery. En Lecture Notes of the Institute for Computer Sciences, Social Informatics and Telecommunications Engineering. Springer Verlag. 124-134. doi:10.1007/978-3-319-49580-4_12S124134Lloret, J., Garcia, M., Atenas, M., Canovas, A.: A QoE management system to improve the IPTV network. Int. J. Commun Syst 24(1), 118–138 (2011)Garcia, M., Canovas, A., Edo, M., Lloret, J.: A QoE management system for ubiquitous IPTV devices. In: The Third International Conference on Mobile Ubiquitous Computing, Systems, Services and Technologies, UBICOMM 2009, Sliema, Malta, 11–16 October 2009Álvarez, A., Pozueco, L., Cabrero, S., García Pañeda, X., García, R., Melendi, D., Díaz Orueta, G.: Adaptive streaming: a subjective catalog to assess the performance of objective QoE metrics. Netw. Protoc. Algorithms 6(2), 123–136 (2014)Jimenez, J.M., Romero, O., Rego, A., Dilendra, A., Lloret, J.: Study of multimedia delivery over software defined networks. Netw. Protoc. Algorithms 7(4), 37–62 (2015)Recomendation UIT/T G.1010: End-user multimedia QoS categories (2001). https://www.itu.int/rec/T-REC-G.1010-200111-I/enRecomendation UIT‑R M.1079-2: Performance and quality of service requirements for International Mobile Telecommunications-2000 (IMT-2000) access networks. https://www.itu.int/dms_pubrec/itu-r/rec/m/R-REC-M.1079-2-200306-I!!PDF-E.pdfGarcia, M., Lloret, J., Edo, M., Lacuesta, R.: IPTV distribution network access system using WiMAX and WLAN technologies. In: Proceedings of the 4th Edition of the UPGRADE-CN Workshop on Use of P2P GRID and Agents for the Development of Content Networks, Munich, Germany, 11–13 June 2009Atenas, M., Sendra, S., Garcia, M., Lloret, J.: IPTV performance in IEEE 802.11 n WLANs. In: IEEE GLOBECOM Workshops 2010, Miami, USA, pp. 929–933, December 2010Cisco Systems Inc. Cisco’s Visual Networking Index Forecast Projects Nearly Half the World’s Population Will Be Connected to the Internet by 2017. http://newsroom.cisco.com/press-release-content?articleId=1197391Lu, X., Tao, S., El Zarki, M., Guérin, R.: Quality based Adaptive Video Over the Internet. Department of ESE, University of Pennsylvania, Philadelphia, PA 19104 (2003)Lee, T.K., Chai, T.Y., Ngoh, L.H., Shao, X., Teo, J.C.M., Zhou, L.: An IMS-based testbed for real-time services integration and orchestration. In: IEEE Asia-Pacific Services Computing Conference (APSCC 2009), Singapore, 7–11 December 2009Mu, M., Mauthe, A., Casson, J., Tyson, G., Garcia, F.: LA1 TestBed: evaluation testbed to assess the impact of network impairments on video quality. In: 5th International Conference on Testbeds and Research Infrastructures for the Development of Networks & Communities and Workshops (TridentCom 2009), Washington, DC, 6–8 April 2009Kuwadekar, A., Al-Begain, K.: User centric quality of experience testing for video on demand over IMS. In: First International Conference on Computational Intelligence, Communication Systems and Networks (CICSYN 2009), Indore, India, 23–25 July 2009Downline Guide, Big Buck Bunny, Sunflower version. http://bbb3d.renderfarming.net/download.htmlFFmpeg. http://www.ffmpeg.org/about.htmlSullivan, G.J., Wiegand, T.: Video compression - from concepts to the H.264/AVC standard. Proc. IEEE 93(1), 18–31 (2005)Estepa, A.J., Estepa, R., Vozmediano, J., Carrillo, P.: Dynamic VoIP codec selection on smartphones. Netw. Protoc. Algorithms 6(2), 22–37 (2014

MHCP: Multimedia Hybrid Cloud Computing Protocol and Architecture for Mobile Devices

[EN] Multimedia cloud computing has appeared as a very attractive environment for the business world in terms of providing cost-effective services with a minimum of entry costs and infrastructure requirements. There are some architecture proposals in the related literature, but there is no multimedia cloud computing architecture with hybrid features specifically designed for mobile devices. In this article, we propose a new multimedia hybrid cloud computing architecture and protocol. It merges existing private and public clouds and combines IaaS, SaaS and SECaaS cloud computing models in order to find a common platform to deliver real time traffic from heterogeneous multimedia and social networks for mobile users. The developed protocol provides suitable levels of QoS, while providing a secure and trusted cloud environment.Jimenez, JM.; Díaz Santos, JR.; Lloret, J.; Romero Martínez, JO. (2019). MHCP: Multimedia Hybrid Cloud Computing Protocol and Architecture for Mobile Devices. IEEE Network. 33(1):106-112. https://doi.org/10.1109/MNET.2018.1300246S10611233

Energy Savings Consumption on Public Wireless Networks by SDN Management

[EN] In order to use the energy more efficiently, network algorithms and protocols must incorporate in their decision mechanisms some functions focused on saving energy. In this paper we have studied different features and parameters of wireless networks to establish their relationship with the power consumption. First, we have analyzed the variation of power consumption of access points (APs) in function of the antenna transmission power. Second, we have collected user information from real public wireless network to determine the real requirements of network resources in real time basis. Based on this information, a new extension for Openflow protocol over Software-Defined Networking (SDN) networks will be proposed to manage the wireless network, with the aim to keep the optimal network performance with minimal power consumption. This extension introduces new Openflow messages and a new function to be incorporated in SDN controllers and Openflow enabled devices. The proposal will be validated by appropriated simulations based on real scenarios: a shopping center and a municipal wireless network.This work has been supported by the Ministerio de Economía y Competitividad , through the Convocatoria 2014. Proyectos I + D - Programa Estatal de Investigación Científica y Técnica de Excelencia in the Subprograma Estatal de Generación de Conocimiento , Project TIN2014-57991-C3-1-P and the Programa para la Formación de Personal Investigador (FPI-2015-S2-884) by the Universitat Politècnica de València .Jimenez, JM.; Romero Martínez, JO.; Lloret, J.; Díaz Santos, JR. (2019). Energy Savings Consumption on Public Wireless Networks by SDN Management. Mobile Networks and Applications. 24(2):667-677. https://doi.org/10.1007/s11036-016-0784-7S667677242Khoa Nguyen K, Jaumard B (2009) Routing engine architecture for next generation routers: evolutional trends. 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Accessed 3 Nov 2016McKeown N, Anderson T, Balakrishnan H, Parulkar G, Peterson L, Rexford J, Shenker S, Turner J (2008) OpenFlow: enabling innovation in campus networks. ACM SIGCOMM Comput Commun Rev 38(2):69–74Dely P, Kassler A, Bayer N (2011) OpenFlow for wireless mesh networks. In 2011 proceedings of 20th international conference on computer communications and networks (ICCCN), July 31-Aug 4 2011, pp 1–6. doi: 10.1109/ICCCN.2011.6006100Guidance document_Lot 26_networked standby_clean FIN.pdf. Available at https://ec.europa.eu/energy/sites/ener/files/documents/Guidance%20document_Lot%2026_Networked%20Standby_clean%20FIN.pdf . Accessed 3 Nov 2016Yang H, Zhang J, Zhao Y, Ji Y, Han J, Lin Y, Qiu YL (2014) Time-aware software defined networking for OpenFlow-based datacenter optical networks. Netw Protocol Algorithm 6(4):77–91Jimenez JM, Romero O, Rego A, Dilendra A, Lloret J (2015) Study of multimedia delivery over software defined networks. Netw Protocol Algorithm 7(4):37–62Jimenez JM, Romero O, Rego A, Dilendra A, Lloret J (2016) Performance study of a software defined network emulator. The twelfth advanced international conference on telecommunications (AICT 2016), May 22–26, 2016, Valencia, SpainMininet An Instant Virtual Network on your Laptop (or other PC) (2016). Available at http://mininet.org /. Accessed 3 Nov 2016Nedevschi S, Popa L, Iannaccone G, Ratnasamy S, Wetherall D (2008) Reducing network energy consumption via sleeping and rate-adaptation. Proceeding NSDI’08 proceedings of the 5th USENIX symposium on networked systems design and implementation, April 16–18, 2008, San Francisco (USA), pp 323–336Feeney LM, Nilsson M (2001) Investigating the energy consumption of a wireless network interface in an Ad Hoc networking environment. In: proceedings of the twentieth annual joint conference of the IEEE computer and communications societies, INFOCOM 2001, vol 3, Anchorage, Alaska, April 22–26, pp. 1548–1557. IEEE (2001)Andrade-Morelli S, Ruiz-Sanchez E, Granell E, Lloret J (2012) Energy consumption of wireless network access points. In second international conference, Gree Nets 2012, Gandia, Spain, October 25–26, 2012, pp 81–91. doi: 10.1007/978–3–642-37977-2_8Chen T, Yang Y, Zhang H, Haesik K, Horneman K (2011) Network energy saving technologies for green wireless access networks. IEEE Wirel Commun 18(5):30–38Tapia A, Maitland C, Stone M (2006) Making IT work for municipalities: Buildingmunicipal wireless networks. Gov Inf Q 23(3):359–380van Drunen R, Koolhaas J, Schuurmans H, Vijn M (2003) Building a wireless community network in the netherland. In: USENIX 2003/Freenix Annual technical conference proceedings, San Antonio, Texas, USA, June 9–14, pp 219–230Vu TH, Nam PN, Thanh T, Hung LT, Van LA, Linh ND, Thien TD, Thanh NH (2012) Power aware OpenFlow switch extension for energy saving in data centers. In international conference on advanced technologies for communications, ATC 2012, IEEE, Hanoi, Vietnam, 10–12 Oct 2012, pp 309–313. doi: 10.1109/ATC.2012.6404282Kaup F, Melnikowitsch S, Hausheer D (2014) Measuring and modeling the power consumption of OpenFlow switches. In IEEE international conference on network and service management (CNSM), Rio de Janeiro, Brazil, 17–21 Nov 2014, pp 181–186DATA SHEET. ARUBA 103 SERIES ACCESS POINTS (2016). Available at: http://www.arubanetworks.com/assets/ds/DS_AP103Series.pdf . Accessed 3 Nov 2016DATA SHEET. ARUBA RAP-100 SERIES REMOTE ACCESS POINTS (2016). Available at: http://www.arubanetworks.com/assets/ds/DS_RAP-100.pdf . Accessed 3 Nov 2016Cisco Aironet 1240AG Series 802.11A/B/G Access Point Data Sheet (2016). Available at: http://www.cisco.com/c/en/us/products/collateral/collaboration-endpoints/unified-ip-phone-7900-series/product_data_sheet0900aecd8031c844.html . 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MWAHCA: A Multimedia Wireless Ad Hoc Cluster Architecture

Wireless Ad hoc networks provide a flexible and adaptable infrastructure to transport data over a great variety of environments. Recently, real-time audio and video data transmission has been increased due to the appearance of many multimedia applications. One of the major challenges is to ensure the quality of multimedia streams when they have passed through a wireless ad hoc network. It requires adapting the network architecture to the multimedia QoS requirements. In this paper we propose a new architecture to organize and manage cluster-based ad hoc networks in order to provide multimedia streams. Proposed architecture adapts the network wireless topology in order to improve the quality of audio and video transmissions. In order to achieve this goal, the architecture uses some information such as each node's capacity and the QoS parameters (bandwidth, delay, jitter, and packet loss). The architecture splits the network into clusters which are specialized in specific multimedia traffic. The real system performance study provided at the end of the paper will demonstrate the feasibility of the proposal.Díaz Santos, JR.; Lloret, J.; Jimenez, JM.; Sendra, S. (2014). MWAHCA: A Multimedia Wireless Ad Hoc Cluster Architecture. Scientific World Journal. 2014. doi:10.1155/2014/913046S2014Lacuesta, R., Lloret, J., Garcia, M., & Peñalver, L. (2010). A Spontaneous Ad Hoc Network to Share WWW Access. EURASIP Journal on Wireless Communications and Networking, 2010(1). doi:10.1155/2010/232083Lloret, J., Garcia, M., Tomás, J., & Boronat, F. (2008). GBP-WAHSN: A Group-Based Protocol for Large Wireless Ad Hoc and Sensor Networks. Journal of Computer Science and Technology, 23(3), 461-480. doi:10.1007/s11390-008-9147-6Yu, J. Y., & Chong, P. H. J. (2005). A survey of clustering schemes for mobile ad hoc networks. IEEE Communications Surveys & Tutorials, 7(1), 32-48. doi:10.1109/comst.2005.1423333Lloret, J., Garcia, M., Bri, D., & Diaz, J. (2009). A Cluster-Based Architecture to Structure the Topology of Parallel Wireless Sensor Networks. Sensors, 9(12), 10513-10544. doi:10.3390/s91210513LEHSAINI, M., GUYENNET, H., & FEHAM, M. (2010). Cluster-based Energy-efficient k-Coverage for Wireless Sensor Networks. Network Protocols and Algorithms, 2(2). doi:10.5296/npa.v2i2.325Zhou, C., & Maxemchuk, N. (2011). Distributed Bottleneck Flow Control in Mobile Ad Hoc Networks. Network Protocols and Algorithms, 3(1). doi:10.5296/npa.v3i1.576Zhang, R., Cai, L., Pan, J., & Shen, X. (Sherman). (2011). Resource management for video streaming in ad hoc networks. Ad Hoc Networks, 9(4), 623-634. doi:10.1016/j.adhoc.2010.08.012Tarique, M. (2010). ISSUES OF LONG-HOP AND SHORT-HOP ROUTING IN MOBILE AD HOC NETWORKS: A COMPREHENSIVE STUDY. Network Protocols and Algorithms, 2(2). doi:10.5296/npa.v2i2.430Abdrabou, A., & Zhuang, W. (2009). Statistical QoS routing for IEEE 802.11 multihop ad hoc networks. IEEE Transactions on Wireless Communications, 8(3), 1542-1552. doi:10.1109/twc.2008.080573Kandris, D., Tsagkaropoulos, M., Politis, I., Tzes, A., & Kotsopoulos, S. (2011). Energy efficient and perceived QoS aware video routing over Wireless Multimedia Sensor Networks. Ad Hoc Networks, 9(4), 591-607. doi:10.1016/j.adhoc.2010.09.00

Aprendizaje Colaborativo en Profesionales de Nuevas Tecnologías

En los cursos de Nuevas Tecnologías de la Información y las Comunicaciones orientados a alumnos con estudios universitarios, se debe considerar en el aprendizaje métodos que permitan formar al alumno utilizando grupos de trabajo y donde las prácticas desempeñadas sean casos reales. Muchos de estos alumnos van a formar parte, o están formando parte, de grupos de trabajo en empresas, grupos de investigación, etc. El método que se propone, pretende desarrollar el currículum de los alumnos desde un entorno colaborativo práctico donde cada alumno es una pieza importante del trabajo a realizar y donde el resultado final depende de todos. Para ello se realizan prácticas colaborativas, con escaso contenido teórico, donde se combinan factores de descubrimiento, análisis y consulta entre compañeros. Posteriormente se realiza una clase magistral y participativa, por parte del profesor, del contenido teórico correspondiente a dichas prácticas.Jiménez Herranz, JM.; Lloret, J.; Esteve Domingo, M.; Díaz Santos, JR. (2004). Aprendizaje Colaborativo en Profesionales de Nuevas Tecnologías. The International Institute of Informatics and Systemics (IIIS). http://hdl.handle.net/10251/671

Fault tolerant mechanism for multimedia flows in wireless ad hoc networks based on fast switching paths

Multimedia traffic can be forwarded through a wireless ad hoc network using the available resources of the nodes. Several models and protocols have been designed in order to organize and arrange the nodes to improve transmissions along the network. We use a cluster-based framework, called MWAHCA architecture, which optimizes multimedia transmissions over a wireless ad hoc network. It was proposed by us in a previous research work. This architecture is focused on decreasing quality of service (QoS) parameters like latency, jitter, and packet loss, but other network features were not developed, like load balance or fault tolerance. In this paper, we propose a new fault tolerance mechanism, using as a base the MWAHCA architecture, in order to recover any multimedia flow crossing the wireless ad hoc network when there is a node failure. The algorithm can run independently for each multimedia flow. The main objective is to keep the QoS parameters as low as possible. To achieve this goal, the convergence time must be controlled and reduced. This paper provides the designed protocol, the analytical model of the algorithm, and a software application developed to test its performance in a real laboratory.This work has been partially supported by Instituto de Telecomunicacoes, Next Generation Networks and Applications Group (NetGNA), Covilha Delegation, and by National Funding from the FCT-Fundacao para a Ciencia e a Tecnologia through the Pest-OE/EEI/LA0008/2013 Project.Díaz Santos, JR.; Lloret, J.; Jimenez, JM.; Sendra, S.; Rodrigues, JJPC. (2014). Fault tolerant mechanism for multimedia flows in wireless ad hoc networks based on fast switching paths. Mathematical Problems in Engineering. 2014:1-12. doi:10.1155/2014/361543S1122014Sendra, S., Lloret, J., Garcia, M., & Toledo, J. F. (2011). Power Saving and Energy Optimization Techniques for Wireless Sensor Neworks (Invited Paper). 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International Journal of Distributed Sensor Networks, 10(5), 480372. doi:10.1155/2014/480372Diaz, J. R., Lloret, J., Jimenez, J. M., & Sendra, S. (2014). MWAHCA: A Multimedia Wireless Ad Hoc Cluster Architecture. The Scientific World Journal, 2014, 1-14. doi:10.1155/2014/913046Sadiq, A. S., Bakar, K. A., Ghafoor, K. Z., Lloret, J., & Khokhar, R. (2013). An Intelligent Vertical Handover Scheme for Audio and Video Streaming in Heterogeneous Vehicular Networks. Mobile Networks and Applications, 18(6), 879-895. doi:10.1007/s11036-013-0465-8Diaz, J. R., Lloret, J., Jiménez, J. M., & Hammoumi, M. (2014). A new multimedia-oriented architecture and protocol for wireless ad hoc networks. International Journal of Ad Hoc and Ubiquitous Computing, 16(1), 14. doi:10.1504/ijahuc.2014.062486Pagani, E., & Rossi, G. P. (1999). Mobile Networks and Applications, 4(3), 175-192. doi:10.1023/a:1019198815518Xue, Y., & Nahrstedt, K. (2004). Providing Fault-Tolerant Ad hoc Routing Service in Adversarial Environments. Wireless Personal Communications, 29(3/4), 367-388. doi:10.1023/b:wire.0000047071.75971.cdBoukerche, A., Werner Nelem Pazzi, R., & Borges Araujo, R. (2006). Fault-tolerant wireless sensor network routing protocols for the supervision of context-aware physical environments. Journal of Parallel and Distributed Computing, 66(4), 586-599. doi:10.1016/j.jpdc.2005.12.007Bheemarjuna Reddy, T., Sriram, S., Manoj, B. S., & Siva Ram Murthy, C. (2006). MuSeQoR: Multi-path failure-tolerant security-aware QoS routing in Ad hoc wireless networks. Computer Networks, 50(9), 1349-1383. doi:10.1016/j.comnet.2005.05.035Chao, H. L., & Chang, C. L. (2008). A fault-tolerant routing protocol in wireless sensor networks. International Journal of Sensor Networks, 3(1), 66. doi:10.1504/ijsnet.2008.016463Melamed, R., Keidar, I., & Barel, Y. (2007). Octopus: A fault-tolerant and efficient ad-hoc routing protocol. 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Digital Rock Physics in Cuttings Using High-Resolution Thin Section Scan Images

Digital rock physics (DRP) has undergone significant advancements in the use of various imaging techniques to acquire three-dimensional volumes and images of rock samples for the computation of petrophysical properties. This study focuses on developing a DRP workflow using high-resolution thin section scans for computing porosity and permeability in cuttings samples. The workflow was tested on quarry sandstone plug samples and artificially generated pseudo-cuttings before applying it to real cuttings from oil and gas wells. The results show that the porosity and permeability values obtained through the DRP workflow are statistically equivalent to those obtained through conventional routine core analysis (RCAL). The workflow was also able to handle the presence of various lithologies in real cuttings samples. The study demonstrates the feasibility of obtaining porosity and permeability values in cutting samples using the DRP approach, offering a fast and cost-effective methodology that provides additional data and allows linking petrophysical properties to image data from the cuttings

Huntington's disease-specific mis-splicing unveils key effector genes and altered splicing factors

Correction of mis-splicing events is a growing therapeutic approach for neurological diseases such as spinal muscular atrophy or neuronal ceroid lipofuscinosis 7, which are caused by splicing-affecting mutations. Mis-spliced effector genes that do not harbour mutations are also good candidate therapeutic targets in diseases with more complex aetiologies such as cancer, autism, muscular dystrophies or neurodegenerative diseases. Next-generation RNA sequencing (RNA-seq) has boosted investigation of global mis-splicing in diseased tissue to identify such key pathogenic mis-spliced genes. Nevertheless, while analysis of tumour or dystrophic muscle biopsies can be informative on early stage pathogenic mis-splicing, for neurodegenerative diseases, these analyses are intrinsically hampered by neuronal loss and neuroinflammation in post-mortem brains. To infer splicing alterations relevant to Huntington's disease pathogenesis, here we performed intersect-RNA-seq analyses of human post-mortem striatal tissue and of an early symptomatic mouse model in which neuronal loss and gliosis are not yet present. Together with a human/mouse parallel motif scan analysis, this approach allowed us to identify the shared mis-splicing signature triggered by the Huntington's disease-causing mutation in both species and to infer upstream deregulated splicing factors. Moreover, we identified a plethora of downstream neurodegeneration-linked mis-spliced effector genes that-together with the deregulated splicing factors-become new possible therapeutic targets. In summary, here we report pathogenic global mis-splicing in Huntington's disease striatum captured by our new intersect-RNA-seq approach that can be readily applied to other neurodegenerative diseases for which bona fide animal models are available.Extremadura Research Centre for Advanced Technologies (CETA-CIEMAT), funded by the European Regional Development Fund (ERDF). CETA-CIEMAT belongs to CIEMAT and the Government of Spai

Pulmonary vascular remodeling and prognosis in patients evaluated for heart transplantation: insights from the OCTOPUS-CHF study

[Abstract] Objective: In patients with advanced heart failure, the intravascular optical coherence tomography (OCT) of subsegmental pulmonary artery measurements is correlated with right heart catheterization parameters. Our aim was to study the prognostic value of pulmonary OCT, right heart catheterization data, and the echocardiographic estimation of pulmonary pressure in patients studied for elective heart transplants. Methods: This research is an observational, prospective, multicenter study involving 90 adults with a one-year follow-up. Results: A total of 10 patients (11.1%) died due to worsening heart failure before heart transplantation, 50 underwent a heart transplant (55.6%), and 9 died in the first year after the transplant. The patients with and without events (mortality or heart failure-induced hospitalization) had similar data regarding echocardiography, right heart catheterization, and pulmonary OCT (with a median estimated pulmonary artery systolic pressure of 42.0 mmHg, interquartile range (IQR) of 30.3-50.0 vs. 47.0 mmHg, IQR 34.6-59.5 and p = 0.79, median pulmonary vascular resistance of 2.2 Wood units, IQR 1.3-3.7 vs. 2.0 Wood units, IQR 1.4-3.2 and p = 0.99, and a median pulmonary artery wall thickness of 0.2 ± 0.5 mm vs. 0.2 ± 0.6 mm and p = 0.87). Conclusion: Pulmonary vascular remodeling (evaluated with echocardiography, right heart catheterization, and pulmonary OCT) was not associated with prognosis in a selected sample of adults evaluated for elective heart transplants. Pulmonary OCT is safe and feasible for the evaluation of these patients.Instituto de Salud Carlos III; PI18/00254European Regional Development Fund; CB16/11/0050