100 research outputs found
Modelado semántico y ubicuo del comercio electrónico mediante Web Services
La demanda de interoperabilidad
semántica y ubicuidad tecnológica en aplicaciones
de comercio electrónico tiene un crecimiento
exponencial. Añadir propiedades inteligentes a la
Web actual, ya es una realidad a través del desarrollo
e implementación de Web Services basados en
estándares de fácil gestión y cada vez más estables,
cumpliendo con los requerimientos básicos de
Calidad de Servicio (QoS). Este trabajo presenta
un análisis de la tecnologÃa de los Web Services con
el principal objetivo de aportar valor añadido a
aplicaciones de Comercio Electrónico; asà como,
exponer una visión general del estado actual de los
Web Services y sus contribuciones a las necesidades
de las empresas en general.Peer Reviewe
Video streaming with quality adaption using collaborative active grid networks
Due to the services and demands of the end
users, Distributed Computing (Grid Technology,
Web Services, and Peer-to-Peer) has been
developedrapidJy in thelastyears. Theconvergence
of these architectures has been possible using
mechanisms such as Collaborative work and
Resources Sharing. Grid computing is a platform to
enable flexible, secure, controlled, scalable,
ubiquitous and heterogeneous services. On the
other hand, Video Streaming applications demand
a greater deployment over connected Internet users.
The present work uses the Acti ve Grid technology
as a fundamental platform to give a solution of
multimediacontentrecovery. This solution takes
into account the following key concepts:
collaborative work, multi-source recovery and
adapti ve quality. A new archi tecture is designed to
deliver video content over a Grid Network. The
acti ve and passi ve roles of the nodes are important
to guarantee a high quality and efficiency for the
video streaming system. The acti ve sender nodes
are the content suppliers, while the passive sender
nodes wiU perform the backup functions, based on
global resource control policies. The aim of the
backup node is minirnize the time to restore the
systemin caseoffailures. In this way, all participant
peers work in a collaborati ve manner following a
mul ti -source recovery scheme.
Furthermore, Video La yered Encoding is used
to manage the video data in a high scalable way,
di viding the video in multiple layers. This video
codification scheme enables thequality adaptation
according to the availability of system resources. In
addition, a buffer by sender peer and by layer is
needed for an effecti ve control ofthe video retrieve.
The QoS will fit considering the state of each buffer
and the measurement tools provide by the Acti ve
Grid on the network nodes. Ke ywords: Peer -to-Peer Grid Architecture,
Services for Active Grids, Streaming Media,
Layered Coding, Quality Adaptation, CoUaborative
Work.Peer Reviewe
Video streaming with quality adaption using collaborative active grid networks
Due to the services and demands of the end
users, Distributed Computing (Grid Technology,
Web Services, and Peer-to-Peer) has been
developedrapidJy in thelastyears. Theconvergence
of these architectures has been possible using
mechanisms such as Collaborative work and
Resources Sharing. Grid computing is a platform to
enable flexible, secure, controlled, scalable,
ubiquitous and heterogeneous services. On the
other hand, Video Streaming applications demand
a greater deployment over connected Internet users.
The present work uses the Acti ve Grid technology
as a fundamental platform to give a solution of
multimediacontentrecovery. This solution takes
into account the following key concepts:
collaborative work, multi-source recovery and
adapti ve quality. A new archi tecture is designed to
deliver video content over a Grid Network. The
acti ve and passi ve roles of the nodes are important
to guarantee a high quality and efficiency for the
video streaming system. The acti ve sender nodes
are the content suppliers, while the passive sender
nodes wiU perform the backup functions, based on
global resource control policies. The aim of the
backup node is minirnize the time to restore the
systemin caseoffailures. In this way, all participant
peers work in a collaborati ve manner following a
mul ti -source recovery scheme.
Furthermore, Video La yered Encoding is used
to manage the video data in a high scalable way,
di viding the video in multiple layers. This video
codification scheme enables thequality adaptation
according to the availability of system resources. In
addition, a buffer by sender peer and by layer is
needed for an effecti ve control ofthe video retrieve.
The QoS will fit considering the state of each buffer
and the measurement tools provide by the Acti ve
Grid on the network nodes. Ke ywords: Peer -to-Peer Grid Architecture,
Services for Active Grids, Streaming Media,
Layered Coding, Quality Adaptation, CoUaborative
Work.Peer Reviewe
Design of an adaptive-rate video-streaming service with different classes of users
The provision of end-to-end Quality of Service (QoS) for multimedia services over IP-based networks is already an open issue. To achieve this goal, service providers need to manage Service Level Agreements (SLAs), which specify parameters of the services operation such as availability and performance. Additional mechanisms are needed to quantitatively evaluate the user-level SLA parameters. This work is focused on the evaluation and assessment of different design options of an adaptive VoD service providing several classes of users and fulfilling the SLA commitments. Based on a straightforward Markov Chain, Markov-Reward Chain (MRC) models are developed in order to obtain various QoS measures of the adaptive VoD service. The MRC model has a clear understanding with the design and operation of the VoD system.5th IFIP International Conference on Network Control & Engineering for QoS, Security and MobilityRed de Universidades con Carreras en Informática (RedUNCI
Design of an adaptive-rate video-streaming service with different classes of users
The provision of end-to-end Quality of Service (QoS) for multimedia services over IP-based networks is already an open issue. To achieve this goal, service providers need to manage Service Level Agreements (SLAs), which specify parameters of the services operation such as availability and performance. Additional mechanisms are needed to quantitatively evaluate the user-level SLA parameters. This work is focused on the evaluation and assessment of different design options of an adaptive VoD service providing several classes of users and fulfilling the SLA commitments. Based on a straightforward Markov Chain, Markov-Reward Chain (MRC) models are developed in order to obtain various QoS measures of the adaptive VoD service. The MRC model has a clear understanding with the design and operation of the VoD system.5th IFIP International Conference on Network Control & Engineering for QoS, Security and MobilityRed de Universidades con Carreras en Informática (RedUNCI
Ancient DNA from Early Human Burials in the Argentine Puna: Insights into Burial Practices and South American Population History
Although the earliest archaeological sites in South America date to the late Pleistocene, little is known about the genetic makeup or mortuary behavior of early hunter-gatherer populations in South America. To help shed light on the burial practices of these hunter-gatherers, as well as the early population history of this region, we extracted ancient DNA from the remains of 13 individuals excavated from early and mid-Holocene archaeological sites in the southern Argentine Puna. These remains are from four locations in the Antofagasta de la Sierra region of northwestern Argentina, and date between 9200 and 3200 YBP. We sequenced 372 base pairs of the first hypervariable region of the mitochondrial DNA to define maternally-inherited genetic lineages, and analyzed a length dimorphism in the amelogenin gene to investigate the sex of each individual. We found that maternally related individuals were sometimes buried together, and several individuals exhibited a mtDNA lineage that is rare in indigenous American populations today. Our results shed light on the early population history of this region and help elucidate the genetic affinities between the prehistoric inhabitants of the Puna and other regions in South America.Fil: Bolnick, Deborah A.. Austin Community College; Estados UnidosFil: Pintar, Elizabeth. Austin Community College; Estados UnidosFil: Martinez, Jorge Gabriel. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Centro CientÃfico Tecnológico Conicet - Tucumán. Instituto Superior de Estudios Sociales. Universidad Nacional de Tucumán. Instituto Superior de Estudios Sociales; ArgentinaFil: DÃaz Matallana, Marcela. Pontificia Universidad Javeriana; ColombiaFil: Mata Miguez, Jaime. University of Texas at Austin; Estados Unidos79th Meeting for the Society for American ArchaeologyAustinEstados UnidosSociety for American Archaeolog
Ancient DNA from Early to Mid-Holocene Burials in Northwestern Argentina: Implications for Understanding the Colonization and Early Populations of South America
Archaeological evidence demonstrates that humans have been living in South America since the late Pleistocene. However, relatively little is known about the genetic diversity present in early hunter-gatherer populations on this continent, and few studies have examined ancient DNA from Pleistocene or early to mid-Holocene human remains from South America. Many questions therefore remain about the early populations of this continent and the routes of migration that were used by some of the earliest settlers.     In this study, we extracted DNA from the remains of 13 individuals unearthed at early and mid-Holocene archaeological sites in northwestern Argentina. The remains come from four locations in the Antofagasta de la Sierra region, in the southern Argentine Puna, and they date between ca. 9500-3330 cal BP. We identified mitochondrial DNA (mtDNA) haplogroups based on coding-region SNPs, and sequenced 372 base pairs of the first hypervariable region of the mtDNA to confirm haplogroup assignments and define mtDNA haplotypes. All results were confirmed through multiple independent DNA extractions and PCR amplifications. We compared the genetic lineages in these individuals with those in other ancient and contemporary populations from the Americas to help elucidate the genetic affinities between the prehistoric inhabitants of the Puna and peoples in other regions. We found that one of the most common mtDNA lineages in these ancient Argentines was haplogroup D4h3a, which is rare in indigenous Americans today but most common along the Pacific coast. Our results shed light on the early populations and routes of migration in South America.Fil: Bolnick, Deborah. Texas A&M University; Estados UnidosFil: DÃaz Matallana, Marcela. Texas A&M University; Estados UnidosFil: Mata Miguez, Jaime. Texas A&M University; Estados UnidosFil: Pintar, Elizabeth Lucia. Texas A&M University; Estados UnidosFil: Martinez, Jorge Gabriel. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Centro CientÃfico Tecnológico Conicet - Tucumán. Instituto Superior de Estudios Sociales. Universidad Nacional de Tucumán. Instituto Superior de Estudios Sociales; Argentina83rd Annual Meeting of the American Association of Physical AnthropologistsCalgaryCanadáAmerican Association of Physical Anthropologist
Design of an adaptive-rate video-streaming service with different classes of users
The provision of end-to-end Quality of Service (QoS) for multimedia services over IP-based networks is already an open issue. To achieve this goal, service providers need to manage Service Level Agreements (SLAs), which specify parameters of the services operation such as availability and performance. Additional mechanisms are needed to quantitatively evaluate the user-level SLA parameters. This work is focused on the evaluation and assessment of different design options of an adaptive VoD service providing several classes of users and fulfilling the SLA commitments. Based on a straightforward Markov Chain, Markov-Reward Chain (MRC) models are developed in order to obtain various QoS measures of the adaptive VoD service. The MRC model has a clear understanding with the design and operation of the VoD system.5th IFIP International Conference on Network Control & Engineering for QoS, Security and MobilityRed de Universidades con Carreras en Informática (RedUNCI
Experimental analysis of high velocity impacts of composite fragments
This work analyses the impact against a rigid plate of carbon epoxy fragments. Experimental tests have been performed by means of a gas gun capable of launching rectangular pieces of composite laminates at a wide range of impact velocities (from 70 to 180 m/s). The impact process has been recorded using three high speed video cameras which allowed to analyse the phenomenon and to obtain the deceleration of the fragment and hence the force time history and impulse induced on the plate. The failure process of the impacted fragments has been studied to identify the main absorption mechanisms and based on that a simple analytical model is proposed in order to predict the erosion and the impact force. (C) 2017 Elsevier Ltd. All rights reserved.This research was done with the financial support of the Spanish Ministry
of Economy and Competitiveness under Project reference DPI2013-41094-
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)
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