2,724 research outputs found

    Dynamic response of periodic infinite structure to arbitrary moving load based on the Finite Element Method

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    [EN] A common problem in railway engineering is the dynamic of repetitive structures subject to moving loads. Bridges, rails or catenaries are the most representative periodic structures, over which the train acts as a moving exciter. Usually, these structures are long enough to consider that their dynamic response is in permanent regime. To assume the steady-state regime some features have to be considered: infinite length structure, perfect periodicity and constant velocity of the moving load. This paper adopts these assumptions and provides the steady-state solution of a generic periodic structure subject to an arbitrary and also periodic moving load. The structure is divided into repetitive blocks modelled by the Finite Element Method. By applying the periodicity condition it is possible to consider the entire structure dynamics with only one block. The problem is stated in the frequency domain and moved back to time domain by means of Discrete Fourier Transform.The authors would like to acknowledge the financial support received from the Spanish Ministry of Economy, Industry and Competitiveness (TRA2017-84736-R).Gil-Romero, J.; Gregori, S.; Tur, M.; Fuenmayor, F. (2022). Dynamic response of periodic infinite structure to arbitrary moving load based on the Finite Element Method. En Proceedings of the YIC 2021 - VI ECCOMAS Young Investigators Conference. Editorial Universitat Politècnica de València. 326-333. https://doi.org/10.4995/YIC2021.2021.12606OCS32633

    Multimedia Data Flow Traffic Classification Using Intelligent Models Based on Traffic Patterns

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    [EN] Nowadays, there is high interest in modeling the type of multimedia traffic with the purpose of estimating the network resources required to guarantee the quality delivered to the user. In this work we propose a multimedia traffic classification model based on patterns that allows us to differentiate the type of traffic by using video streaming and network characteristics as input parameters. We show that there is low correlation between network parameters and the delivered video quality. Because of this, in addition to network parameters, we also add video streaming parameters in order to improve the efficiency of our system. Finally, it should be noted that, based on the objective video quality received by the user, we have extracted traffic patterns that we use to perform the development of the classification model.This work has been supported by the Ministerio de Economia y Competitividad in the Programa Estatal de Fomento de la Investigacion Cientifica y Tecnica de Excelencia, Subprograma Estatal de Generacion de Conocimiento within the Project with reference TIN2017-84802-C2-1-P.Canovas Solbes, A.; Jimenez, JM.; Romero Martínez, JO.; Lloret, J. (2018). Multimedia Data Flow Traffic Classification Using Intelligent Models Based on Traffic Patterns. IEEE Network. 32(6):100-107. doi:10.1109/MNET.2018.180012110010732

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

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    [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

    Architecture and Protocol to Optimize Videoconference in Wireless Networks

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    [EN] In the past years, videoconferencing (VC) has become an essential means of communications. VC allows people to communicate face to face regardless of their location, and it can be used for different purposes such as business meetings, medical assistance, commercial meetings, and military operations. There are a lot of factors in real-time video transmission that can affect to the quality of service (QoS) and the quality of experience (QoE). The application that is used (Adobe Connect, Cisco Webex, and Skype), the internet connection, or the network used for the communication can affect to the QoE. Users want communication to be as good as possible in terms of QoE. In this paper, we propose an architecture for videoconferencing that provides better quality of experience than other existing applications such as Adobe Connect, Cisco Webex, and Skype. We will test how these three applications work in terms of bandwidth, packets per second, and delay using WiFi and 3G/4G connections. Finally, these applications are compared to our prototype in the same scenarios as they were tested, and also in an SDN, in order to improve the advantages of the prototype.This work has been supported by the "Ministerio de Economia y Competitividad" in the "Programa Estatal de Fomento de la Investigacion Cientifica y Tecnica de Excelencia, Subprograma Estatal de Generacion de Conocimiento" within the project under Grant TIN2017-84802-C2-1-P.Jimenez, JM.; García-Navas, JL.; Lloret, J.; Romero Martínez, JO. (2020). Architecture and Protocol to Optimize Videoconference in Wireless Networks. Wireless Communications and Mobile Computing. 2020:1-22. https://doi.org/10.1155/2020/4903420S122202

    Energy Savings Consumption on Public Wireless Networks by SDN Management

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    [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. Network Protocols and Algorithms 1(1):62–85. doi: 10.5296/npa.v1i1.151Cisco Visual Networking Index: Global Mobile Data Traffic Forecast Update, 2015–2020 White Paper (2016). Available at: http://www.cisco.com/c/en/us/solutions/collateral/service-provider/visual-networking-index-vni/mobile-white-paper-c11-520862.html . Accessed 3 Nov 2016Recommended Power Management Settings (2016). Available at https://web.archive.org/web/20071125104605/http://www.climatesaverscomputing.org/tools/pwr_mgmt.html . Accessed 3 Nov 2016WWF International website (2016). Available at http://wwf.panda.org /. Accessed 3 Nov 2016ENERGY STAR (2016). The simple choice for energy efficiency. Available at https://www.energystar.gov /. 3 Nov 2016Definition WHAT IS SDN? (2016). Available at https://www.opennetworking.org/sdn-resources/sdn-definition . Accessed 3 Nov 2016OpenFlow (2016). Available at: https://www.opennetworking.org/sdn-resources/openflow . 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 . Accessed 3 Nov 2016Cisco Aironet 1230AG Series 802.11A/B/G Access Point Data Sheet (2016). Available at: http://www.cisco.com/c/en/us/products/collateral/wireless/aironet-1230-ag-series/product_data_sheet0900aecd801b9068.html . Accessed 3 Nov 2016Cisco Aironet 1130AG IEEE 802.11 A/B/G Access Point (2016). Available at: http://www.cisco.com/c/en/us/products/collateral/collaboration-endpoints/unified-ip-phone-7900-series/product_data_sheet0900aecd8031c844.html . Accessed 3 Nov 2016Aerohive AP121 (2016). Available at: http://media.aerohive.com/documents/Aerohive_Datasheet_AP121 . Accessed 3 Nov 2016Aerohive AP230 (2016). Available at: http://media.aerohive.com/documents/Aerohive_Datasheet_AP230.pdf . Accessed 3 Nov 2016Aerohive AP330 (2016). Available at: http://media.aerohive.com/documents/Aerohive_Datasheet_AP330.pdf . Accessed 3 Nov 201

    Avalanche criticality in the martensitic transition of Cu67.64Zn16.71Al15.65 shape-memory alloy: a calorimetric and acoustic emission study

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    The first-order diffusionless structural transition in Cu67.64Zn16.71Al15.65 is characterized by jerky propagation of phase fronts related to the appearance of avalanches. In this paper, we describe a full analysis of this avalanche behavior using calorimetric heat-flux measurements and acoustic emission measurements. Two different propagation modes, namely, smooth front propagation and jerky avalanches, were observed in extremely slow measurements with heating and cooling rates as low as a few 10−3 K/h. Avalanches show criticality where each avalanche leads to a spike in the heat flux. Their statistical analysis leads to a power law [P(E)∼E−ε, where P(E)dE is the probability to observe an avalanche with energy E in an interval between E and E+dE] with an energy exponent of ε=2.15±0.15 in excellent agreement with the results of acoustic emission measurements. Avalanches appear to be more common for heating rates faster than 5×10−3 K/h whereas smooth front propagation occurs in all calorimetric measurements and (almost) exclusively for slower heating rates. Repeated cooling runs were taken after a waiting time of 1 month (and an intermediate heating run). Correlations between the avalanche sequences of the two cooling runs were found for the strongest avalanche peaks but not for the full sequence of avalanches. The memory effect is hence limited to strong avalanches

    Efecto de la fertilización y época de corte de las paniculas sobre la producción de semilla de pasto Guinea (Panicum maximum Jacq.)

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    En el Centro Experimental Nataima, localizado en el municipio de Espinal, Tolima, temperatura media de 27 C. precipitación promedia anual de 1.551,9 mm y altura de 385 m.s.n.m., se efectuó un ensayo de campo con el objeto de determinar el efecto de Ia fertilización con N, P y K y época de corte de las panículas sobre Ia producción de semilla de pasto guinea (Panicum maximum Jacq.). Se observó que el intervalo entre cortes y dosis de N afectaron significativamente tanto Ia producción total de semillas como Ia mayoría de los componentes del rendimiento. Los rendimientos en semilla desgranada y sin desgranar (peso fresco), número de macollas y panículas por planta y peso de semilla por panícula. se afectaron en forma altamente significativa según Ia frecuencia en los cortes de Ia panícula y las diferentes dosis de N. La fertilización con P y K no fue significativa para ninguna de [as evaluaciones mencionadas. De acuerdo a las regresiones y correlaciones se deduce que los factores que más contribuyeron al rendimiento fueron el número de macollas y el número de panículas por planta y que éstas a su vez presentaron una correlación altamente significativa con el peso de semilla llena por panícula.A field experiment was conducted to study the effect of N, P and K fertilization and time of cutting of the panicle, on seed production of guinea grass. Panicum maximum Jacq., the trial was conducted at Nataima Agricultural Experiment Station in Espinal, Tohma, with a mean temperature of 27°C, 1.552 mm of precipitation and 385 meters of altitude. The data obtained showed that cut interval and N fertilization significatively affected total seed production as well as the mejority of yield components. It was observed that the shelling and non shelling seed production (fresh weight), number of panicles and stalks per plant and seed weight per panicle were highly significant affected by frecuency of cutting and N levels. Fertilization with P and K did not significantly affected the studied parameters. According to the regression and correlation analysis, it is concluded that the most contributing factors to seed yields were the number of bunch stalks and the number of panicles per plant. These two variables showed a highly significant correlation with seed weight per panicle.Ganado de doble propósito-Ganaderia doble proposit

    Substituted tetrahydroisoquinolines: synthesis, characterization, antitumor activity and other biological properties

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    A novel group of aryl methyl sulfones based on nonsteroidal anti-inflammatory compounds exhibiting a methyl sulfone instead of the acetic or propionic acid group was designed, synthesized and evaluated in vitro for inhibition against the human cyclooxygenase of COX-1 and COX-2 isoenzymes and in vivo for anti-inflammatory activity using the carrageenan induced rat paw edema model in rats. Also, in vitro chemosensitivity and in vivo analgesic and intestinal side effects were determined for defining the therapeutic and safety profile. Molecular modeling assisted the design of compounds and the interpretation of the experimental results. Biological assay results showed that methyl sulfone compounds 2 and 7 were the most potent COX inhibitors (IC50 between 0.04 and 0.71 M). Also, these highly active methyl sulfones displayed greater COX-2 activity than the parent carboxylic NSAIDs, thus indicating that the replacement of the acetic or propionic acids by a methyl sulfone group enables some of these structures to possess higher COX-2 inhibitory activity than that of the corresponding alkyl carboxylic analogues. The improved inhibitory activity is attributed to the higher flexibility of the sulfone-receptor interaction that enables more profound exploration of the binding site compared with that of acidic analogues. This observation is underpinned by molecular modeling studies that indicates a change in the binding mode or mechanism compared to the standard binding mode displayed by ibuprofen. The most promising compounds 2 and 7 possess a therapeutical profile that enables their chemical scaffolds to be utilized for development of new NSAIDs

    Humanized mice in dengue research: a comparison with other mouse models

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    Abstract: Dengue virus (DENV) is an arbovirus of the Flaviviridae family and is an enveloped virion containing a positive sense single-stranded RNA genome. DENV causes dengue fever (DF) which is characterized by an undifferentiated syndrome accompanied by fever, fatigue, dizziness, muscle aches, and in severe cases, patients can deteriorate and develop life-threatening vascular leakage, bleeding, and multi-organ failure. DF is the most prevalent mosquito-borne disease affecting more than 390 million people per year with a mortality rate close to 1% in the general population but especially high among children. There is no specific treatment and there is only one licensed vaccine with restricted application. Clinical and experimental evidence advocate the role of the humoral and T-cell responses in protection against DF, as well as a role in the disease pathogenesis. A lot of pro-inflammatory factors induced during the infectious process are involved in increased severity in dengue disease. The advances in DF research have been hampered by the lack of an animal model that recreates all the characteristics of this disease. Experiments in nonhuman primates (NHP) had failed to reproduce all clinical signs of DF disease and during the past decade, humanized mouse models have demonstrated several benefits in the study of viral diseases affecting humans. In DENV studies, some of these models recapitulate specific signs of disease that are useful to test drugs or vaccine candidates. However, there is still a need for a more complete model mimicking the full spectrum of DENV. This review focuses on describing the advances in this area of research
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