A novel P2P and cloud computing hybrid architecture for multimedia streaming QoS cost functions

Since its appearance, peer-to-peer technology has given raise to various multimedia streaming applications. Today, cloud computing offers different service models as a base for successful end user applications. In this paper we propose joining peer-to-peer and cloud computing into new architectural realization of a distributed cloud computing network for multimedia streaming, in a both centralized and peer-to-peer distributed manner. This architecture merges private and public clouds and it is intended for a commercial use, but in the same time scalable to offer the possibility of non-profitable use. In order to take advantage of the cloud paradigm and make multimedia streaming more efficient, we introduce APIs in the cloud, containing build-in functions for automatic QoS calculation, which permits negotiating QoS parameters such as bandwidth, jitter and latency, among a cloud service provider and its potential clients

Advanced Videoconferencing based on WebRTC

Lately, videoconference applications have experienced an evolution towards the World Wide Web. New technologies have given browsers real-time communications capabilities. In this context, WebRTC aims to provide this functionality by following and defining standards. Being a new effort, WebRTC still lacks advanced videoconferencing services such as session recording, media mixing and adjusting to varying network conditions. This paper analyzes these challenges and proposes an architecture based on a traditional communications entity, the Multipoint Control Unit or MCU as a solution

A cost-effective methodology applied to videoconference services over hybrid clouds

This paper tackles the optimization of applications in multi-provider hybrid cloud scenarios from an economic point of view. In these scenarios the great majority of solutions offer the automatic allocation of resources on different cloud providers based on their current prices. However our approach is intended to introduce a novel solution by making maximum use of divide and rule. This paper describes a methodology to create cost aware cloud applications that can be broken down into the three most important components in cloud infrastructures: computation, network and storage. A real videoconference system has been modified in order to evaluate this idea with both theoretical and empirical experiments. This system has become a widely used tool in several national and European projects for e-learning and collaboration purposes

Videoconference capacity Leasing on Hybrid Clouds.

This paper proposes a new methodology focused on implementing cost effective architectures on Cloud Computing systems. With this methodology the paper presents some disadvantages of systems that are based on single Cloud architectures and gives some advices for taking into account in the development of hybrid systems. The work also includes a validation of these ideas implemented in a complete videoconference service developed with our research group. This service allows a great number of users per conference, multiple simultaneous conferences, different client software (requiring transcodification of audio and video flows) and provides a service like automatic recording. Furthermore it offers different kinds of connectivity including SIP clients and a client based on Web 2.0. The ideas proposed in this article are intended to be a useful resource for any researcher or developer who wants to implement cost effective systems on several Cloud

Introducing mobile edge computing capabilities through distributed 5G Cloud Enabled Small Cells

Current trends in broadband mobile networks are addressed towards the placement of different capabilities at the edge of the mobile network in a centralised way. On one hand, the split of the eNB between baseband processing units and remote radio headers makes it possible to process some of the protocols in centralised premises, likely with virtualised resources. On the other hand, mobile edge computing makes use of processing and storage capabilities close to the air interface in order to deploy optimised services with minimum delay. The confluence of both trends is a hot topic in the definition of future 5G networks. The full centralisation of both technologies in cloud data centres imposes stringent requirements to the fronthaul connections in terms of throughput and latency. Therefore, all those cells with limited network access would not be able to offer these types of services. This paper proposes a solution for these cases, based on the placement of processing and storage capabilities close to the remote units, which is especially well suited for the deployment of clusters of small cells. The proposed cloud-enabled small cells include a highly efficient microserver with a limited set of virtualised resources offered to the cluster of small cells. As a result, a light data centre is created and commonly used for deploying centralised eNB and mobile edge computing functionalities. The paper covers the proposed architecture, with special focus on the integration of both aspects, and possible scenarios of application.Peer ReviewedPostprint (author's final draft

Architectures for streaming in P2P and cloud scenarios with SDN-managed QoS cost functions

In over three decades timeline the peer-to-peer technology was a foundation for numerous advancements in the domain of file sharing, video on-demand and real-time communication services. Among them, providing live streaming video over P2P networks was one of the most proactive and challenging services. Despite becoming a replacement of the costly client-server models from the past, it required reliable modular operation in order to make a holistic working service. Major issue in this approach is maintaining a robust overlay topology under dynamic network quality conditions and in the presence of peer churn. The user behavior furthermore has been a subject of many incentive mechanisms to encourage altruism vs. free-riding and mitigate malicious users. Finally, ensuring sensible QoS in live video delivery is a recurring topic to date. The cloud computing milestone had a dominant influence in the design of new applications and services. It grew into de facto technology for value-added services, due to its enhanced business strategy bound to on-demand lease of elastic virtual resources with attractive pay-per-use policies. The cloud providers have moreover enabled flexible provisioning of robust and scalable services. This thesis offers several contributions in terms of architecture, algorithms and technical solutions that have as objective enhancing the classical P2P streaming solutions with novel elements for achieving quality of service-based tiered business model, complemented with incentives based on discount to achieve improved system welfare. The set of contributions uses the converged P2P and cloud technologies to offer enhanced features and services. First of all we created a hybrid architecture for live streaming to address some of the common problems in P2P streaming - scalability, incentives and QoS. To assess the advantages and the feasibility of the proposal, we emulated realistic use-case scenarios in a mixed cloud-P2P environment. We elaborated later a discount incentive model bound to the streaming service that offers a monetary remuneration to motivate increased cooperation. The analytical study of the incentives pointed out the benefits in the streaming service to users' welfare and the provider's profit. The second phase onboarded the SDN technology in the scope of contributions, driven by its attribute of full network manageability governed by a central control entity. The seamless control of network segments that were previously out of range for the service developers, catalyzed major opportunities in SDN. Founded on the QoS control primitives from the OpenFlow specification, a proof of concept service for SDN-based QoS adjustment is presented and APIs are offered to service developers in order to trigger external quality assessment for real-time video services. Finally a service function chain algorithm and proof of concept is delivered as value-added service contribution in the context of video quality adjustment using network function virtualization. --------------------------------------------------------------------------------------------------------------------------------- En más de tres décadas, la tecnología peer-to-peer fue una base para numerosos avances en el dominio del uso compartido de archivos, video bajo demanda y servicios de comunicación en tiempo real. Entre ellos, la transmisión de video en vivo a través de redes P2P fue uno de los servicios más proactivos y desafiantes. A pesar de convertirse en un sustituto de los costosos modelos cliente-servidor del pasado, se requiere una operación modular fiable con el fin de hacer un servicio integral. El principal problema en este enfoque es el mantenimiento de una topología de superposición robusta bajo condiciones dinámicas de calidad de red y en presencia de "churn" de pares. El comportamiento del usuario, además, ha sido objeto de muchos mecanismos de incentivo para fomentar el altruismo frente a los "free-riders" y mitigar a los usuarios malintencionados. Por último, asegurar QoS sensible en la entrega de video en vivo es un tema recurrente hasta la fecha. El hito de la computación en la nube tuvo una influencia dominante en el diseño de nuevas aplicaciones y servicios. Se convirtió en tecnología de facto para los servicios de valor añadido, debido a su estrategia de negocio mejorada vinculada al alquiler bajo demanda de recursos virtuales elásticos con políticas atractivas de pago por uso. Los proveedores de la nube han permitido, además, el aprovisionamiento flexible de servicios robustos y escalables. Esta tesis ofrece varias contribuciones en términos de arquitectura, algoritmos y soluciones técnicas que tienen como objetivo mejorar las clásicas soluciones de streaming P2P con elementos novedosos para lograr un modelo de negocio basado en la calidad de servicio, complementado con incentivos basados en descuento para mejorar el bienestar del sistema. El conjunto de contribuciones utiliza las tecnologías convergentes P2P y cloud para ofrecer características y servicios mejorados. En primer lugar, hemos creado una arquitectura híbrida para la transmisión en vivo y así abordar algunos de los problemas comunes en la transmisión en tiempo real P2P: escalabilidad, incentivos y QoS. Para evaluar las ventajas y la viabilidad de la propuesta, emulamos escenarios realistas de casos de uso en un ambiente mixto de cloud-P2P. Más tarde elaboramos un modelo de incentivo de descuento vinculado al servicio de streaming que ofrece una remuneración monetaria para motivar una mayor cooperación. El estudio analítico de los incentivos destacó los beneficios en el servicio de streaming para el bienestar de los usuarios y los beneficios del proveedor. La segunda fase de investigación incluyó la tecnología SDN en el ámbito de las contribuciones, impulsadas por su atributo de gestión de red completa gobernada por una entidad de control central. El control robusto y continuo de los segmentos de red que antes estaban fuera de rango para los desarrolladores de servicios, dio lugar a grandes oportunidades de nuevos desarrollos basados en SDN. Fundada en las primitivas de control QoS de la especificación OpenFlow, se presenta un servicio de prueba de concepto para ajuste de QoS basado en SDN y se ofrecen APIs a los desarrolladores de servicios para activar la evaluación de calidad externa para servicios de video en tiempo real. Finalmente, un algoritmo de cadena de funciones de servicio y una prueba de concepto se entrega como contribución de servicio de valor añadido, en el contexto del ajuste de calidad de vídeo mediante la virtualización de funciones de red

Laparascopic surgery at the cholecystectomia

Laparoscopic surgery is a type of minimally invasive surgery is performed through a few small holes in the abdomen. Specialized camera optical fiber is passed through one of these holes in order to visualize the interior of the stomach. Through other openings introduced surgical instruments operation is performed.Laparoscopic interventions performed in more surgery but usually applies to cholecystectomia (removal of the gall bladder

Anatomical variations gall bladder of importance for laparoscopic cholecystectomy

Laparoscopic cholecystectomy is a routine operation throughout the world and in our country. It is performed under general anesthesia. The aim of this study is to determine the anatomic variations gall bladder to successfully performed laparoscopic cholecystectomy. The survey was done in Gob "8th September" in Skopje (Republic of Macedonia) 2014. UZ-abdominal gall bladder a totally86 patients, (33 female and 53 male), in age from 35 to 82, were under observation. Normal appearance of the gall bladder is found in 70% of cases, 8% folded, 10% of the double, 15% of left-sided, and in 2% of the gall bladder was missing. In 20% of cases of cystic duct is shorter, which is important because of the connection of the main bile duct, if you need to carry out interventions. Before each laparoscopic cholecystectomy were made with the abdomen-gallbladder. In order to avoid effects at this point as the bleeding, violation of the ductus choledochus, injuries ductus hepaticus dexter