795 research outputs found

    The natural history of type II odontoid fractures in the elderly population. A retrospective study over a 14 years period.

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    Odontoid fractures are the most common cervical fractures in the adult population. They represent 9 to 18 % of all cervical fractures and the type II is the most common. The incidence of neurologic deficits (ND) in odontoid fractures varies between 3 to 25%. A recent study showed that patients with ND had a mortality rate increased by 4.72 times and a complication rate higher of 1.18 times. The most common complication in patients with ND was respiratory distress8. Surprisingly, although type II odontoid fractures are frequent cervical fractures, their natural history has been poorly described. Surgery for odontoid fractures is well described. However, there are so far guidelines based on class II and class III evidence only regarding indications for surgery and regarding surgical techniques. The class II guidelines recommend to consider surgical stabilization and fusion for type II odontoid in patients over 50 years of age. The class III recommendations are to first manage non-displaced odontoid type II fracture with external immobilization and that translation of 5mm or more is associated with a high rate of non- union with the conservative treatment and should be treated surgically

    Identifying Critical Factors in Managing University Technology Transfer and Commercialization Units

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    Given the increasing interest worldwide in the growth of new technology-based companies, the aim of the present paper is to contribute to the future design of patent commercialization and spin-off creation units on behalf of university authorities and national or regional innovation agencies. Our analysis was based on 52 public technology transfer units. Six unit typologies were identified in the analysis. From the results, the proposed recommendations are focused on some critical factors such as a university’s research mass, specialized personnel of the technology transfer units, their profile, expertise and cost, as well as ideas collected from some experts in the field.university; Science Park; technology transfer; commercialization; spin-off.

    ISAC6+ Delivering Smarter Administration through innovation - a Benefits Realisation approach to ensuring success.

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    The paper describes how the Project Management discipline of benefits realisation has been applied to an EU funded E-government initiative. It explores the benefits of using this approach, the challenges to be addressed, and suggest a framework for applying the approach to other local and national e-government initiatives. One of the key project objectives is to demonstrate through the pilot that implementation of the iSAC6+ system will provide value for money by delivering the desired benefits both to government office users and citizens. The approach described here focuses on costs and benefits generated by use of the system. There are staff costs for training, support and operation, technical costs for integrating iSAC6+ in to existing systems and websites, and more significantly organisational costs for designing and implementing new procedures and working practices. Citizens too will incur costs to access and use the service. In iSAC6+ we have created a model of costs and benefits which can be applied in the short term to the pilot, and in the longer term to a much larger number of public organisations. The aim of the Benefits Realisation model is to demonstrate that iSAC6+ is capable of delivering value for money, and thus to justify the investment needed for expanding its use. Information Technology project success or failure is traditionally judged against objectives set during initial project planning. Enterprises, both public and private sector, have found this approach inadequate because long term costs and benefits do not occur until after the project has completed. Benefits Realisation emerged in the 1990s and developed two roles: a discipline for anticipating and quantifying the expected value of a project in terms of the costs and benefits which will accrue after the project itself is complete; and an over-arching project management philosophy. The paper uses the case study experience to comment upon these two different perspectives. The model developed within the project is based upon the recognised public sector costing formula, the Standard Cost model (SCM) but goes much further by integrating it into a Benefits Realisation tool which creates an audit trail from organisational strategic aims through to detailed cost measures for both quantitative and qualitative incidences

    H-P2PSIP: Interconnection of P2PSIP domains for Global Multimedia Services based on a Hierarchical DHT Overlay Network

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    The IETF P2PSIP WG is currently standardising a protocol for distributed mul- timedia services combining the media session functionality of SIP and the decentralised distribution and localisation of resources in peer-to-peer networks. The current P2PSIP scenarios only consider the infrastructure for the connectivity inside a single domain. This paper proposes an extension of the current work to a hierarchical multi-domain scenario: a two level hierarchical peer-to-peer overlay architecture for the interconnection of different P2PSIP domains. The purpose is the creation of a global decentralised multimedia services in enterprises, ISPs or community networks. We present a study of the Routing Performance and Routing State in the particular case of a two-level Distributed Hash Table Hierarchy that uses Kademlia. The study is supported by an analytical model and its validation by a peer-to-peer simulator.En prens

    Analysing the Adoption of Energy-Saving Technologies in Manufacturing Firms

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    The present book chapter aims to (i) map the adoption of energy-saving technologies (EST) in manufacturing and (ii) identify structural and operational characteristics that are expected to correlate with EST implementation. The empirical evidence is collected through the European Manufacturing Survey. The analysis presented corresponds to the Spanish subsample 2012 edition. Our main result points to a relatively low implementation of EST, also interpretable as a still unexploited potential these technologies have for manufacturers. Other main findings show (i) a relatively still modest implementation of most EST and (ii) a possible relationship between high implementation of EST and perceived energy efficiency as a consequence of implementation. The chapter draws implications for practice and research

    Benefits on using H-P2PSIP in mobile environments

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    Proceeding of: VIII Jornadas de Ingeniería Telemática (JITEL '09), Universidad Politécnica de Cartagena, Cartagena, Murcia, 15-17 de septiembre de 2009The use of peer-to-peer technologies is increasing everyday and the improvement of mobility technologies is a reality. Now, it is expected that peer-to-peer applications run on mobile devices, but the conjunction of these two technologies is an open research issue. The user mobility impacts on the churn suffered by peer-to-peer networks and consequently it impacts on their performance. Therefore, some mechanisms are necessary to minimize this undesirable effect. Our proposal tries to solve this problem by using a Hierarchical P2PSIP architecture where different overlays are used for different peer mobility behaviours and they are interconnected between them through an interconnection overlay. In this way it is possible for peers that share the same behaviour to choose a certain protocol or to optimize some functionality that suits best with their mobility situation, while maintaining connectivity with all peers.This research work is being supported by the European Commission under the IST Content Network of Excellence3 (FP6-2006-IST-038423), by the Regional Government of Madrid under the BioGridNet4 project (CAM, S-0505/TIC- 0101) and by the Ministry of Science and Innovation under the CONPARTE project (MEC, TEC2007-67966-C03-03/TCM).No publicad

    Clustering product innovators: a comparison between conventional and green product innovators

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    [EN] This paper aims at analysing firms implementing new products. Based on a cluster analysis, three types of manufacturers have been identified representing different types of product innovators according to the competitiveness factors important for their business, environmentally sensitive new products, and a performance indicator, such as the share of turnover from new products.Pons, M.; Bikfalvi, A.; Llach, J. (2018). Clustering product innovators: a comparison between conventional and green product innovators. International Journal of Production Management and Engineering. 6(1):37-46. doi:10.4995/ijpme.2018.8762SWORD37466

    Peer-to-peer television for the IP multimedia subsystem

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    Peer-to-peer (P2P) video streaming has generated a significant amount of interest in both the research community and the industry, which find it a cost-effective solution to the user scalability problem. However, despite the success of Internet-based applications, the adoption has been limited for commercial services, such as Internet Protocol Television (IPTV). With the advent of the next-generation-networks (NGN) based on the IP Multimedia Subsystem (IMS), advocating for an open and inter-operable architecture, P2P emerges as a possible alternative in situations where the traditional mechanisms are not possible or economically feasible. This work proposes a P2P IPTV architecture for an IMS-based NGN, called P2PTV, which allows one or more service providers to use a common P2P infrastructure for streaming the TV channels to their subscribers. Instead of using servers, we rely on the uploading capabilities of the user equipments, like set-top boxes, located at the customers’ premise. We comply with the existing IMS and IPTV standards from the 3rd Generation Partnership Project (3GPP) and the Telecommunications and Internet converged Services and Protocols for Advanced Networking (TISPAN) bodies, where a centralized P2PTV application server (AS) manages the customer access to the service and the peer participation. Because watching TV is a complex and demanding user activity, we face two significant challenges. The first is to accommodate the mandatory IMS signaling, which reserves in the network the necessary QoS resources during every channel change, establishing a multimedia session between communicating peers. The second is represented by the streaming interruptions, or churn, when the uploading peer turns off or changes its current TV channel. To tackle these problems, we propose two enhancements. A fast signaling method, which uses inactive uploading sessions with reserved but unused QoS, to improve the tuning delay for new channel users. At every moment, the AS uses a feedback based algorithm to compute the number of necessary sessions that accommodates well the demand, while preventing the over-reservation of resources. We approach with special care mobility situations, where a proactive transfer of the multimedia session context using the IEEE 802.21 standard offers the best alternative to current methods. The second enhancement addresses the peer churn during channel changes. With every TV channel divided into a number of streams, we enable peers to download and upload streams different from their current channel, increasing the stability of their participation. Unlike similar work, we benefit from our estimation of the user demand and propose a decentralized method for a balanced assignment of peer bandwidth. We evaluate the performance of the P2PTV through modeling and large-scale computer simulations. A simpler experimental setting, with pure P2P streaming, indicates the improvements over the delay and peer churn. In more complex scenarios, especially with resource-poor peers having a limited upload capacity, we envision P2P as a complementary solution to traditional approaches like IP multicast. Reserving P2P for unpopular TV channels exploits the peer capacity and prevents the necessity of a large number of sparsely used multicast trees. Future work may refine the AS algorithms, address different experimental scenarios, and extend the lessons learned to non-IMS networks. ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------La transmisión de vídeo con tecnologías peer-to-peer (P2P) ha generado un gran interés, tanto en la industria como en la comunidad científica, quienes han encontrado en dicha unión la solución para afrontar los problemas de escalabilidad de la transmisión de vídeo, reduciendo al mismo tiempo sus costes. A pesar del éxito de estos mecanismos en Internet, la transmisión de vídeo mediante técnicas P2P no se ha utilizado en servicios comerciales como puede ser el de televisión por IP (IPTV). Con la aparición de propuestas de redes de próxima generación basadas en el IP Multimedia Subsystem (IMS), que permite una arquitectura abierta e interoperable, los mecanismos basados en P2P emergen como posibles alternativas en situaciones donde los mecanismos tradicionales de transmisión de vídeo no se pueden desplegar o no son económicamente viables. Esta tesis propone una arquitectura de servicio de televisión peer-to-peer para una red de siguiente generación basada en IMS, que abreviaremos como P2PTV, que permite a uno o más proveedores de servicio utilizar una infraestructura P2P común para la transmisión de canales de TV a sus suscriptores. En vez de utilizar varios servidores, proponemos utilizar la capacidad de envío de los equipos de usuario, como los set-top boxes, localizados en el lado del cliente. En esta tesis extendemos los trabajos de estandarización sobre IMS IPTV de los organismos 3rd Generation Partnership Project (3GPP) y del Telecommunications and Internet converged Services and Protocols for Advanced Networking (TISPAN), donde un servidor de aplicación (AS) central de P2PTV administra el acceso de los clientes al servicio y permite compartir los recursos de los equipos. Debido a que el acceso a los canales de TV por parte de los usuarios es una actividad compleja, nos enfrentamos a dos retos importantes. El primero es administrar la señalización de IMS, con la cual se reservan los recursos de QoS necesarios durante cada cambio de canal, estableciendo una sesión multimedia entre los diferentes elementos de la comunicación. El segundo está representado por las interrupciones de la reproducción de video, causado por los equipos que sirven dicho vídeo cuando estos se desconectan del sistema o cuando cambian de canal. Para afrontar estos retos, proponemos dos mejoras al sistema. La primera mejora introduce el método de señalización rápida, en la cual se utilizan sesiones multimedia inactivas pero con recursos reservados para acelerar las conexiones entre usuarios. En cada momento, el AS utiliza la información extraída del algoritmo propuesto, que calcula el número de sesiones necesarias para administrar la demanda de conexiones, pero sin realizar una sobre-estimación, manteniendo bajo el uso de los recursos. Hemos abordado con especial cuidado la movilidad de los usuarios, donde se ha propuesto una transferencia de sesión pro-activa utilizando el estándar IEEE 802.21, el cual brinda una mejor alternativa que los métodos propuestos hasta la fecha. La segunda mejora se enfoca en las desconexiones de usuarios durante cambios de canal. Dividiendo los canales de TV en varios segmentos, permitimos a los equipos descargar o enviar diferentes partes de cualquier canal, aumentando la estabilidad de su participación. A diferencia de otros trabajos, nuestra propuesta se beneficia de la estimación de la demanda futura de los usuarios, proponiendo un método descentralizado para una asignación balanceada del ancho de banda de los equipos. Hemos evaluado el rendimiento del sistema P2PTV a través de modelado y de simulaciones de ordenador en sistemas IPTV de gran escala. Una configuración simple, con envío P2P puro, indica mejoras en el retardo y número de desconexiones de usuarios. En escenarios más complejos, especialmente con equipos con pocos recursos en la subida, sugerimos el uso de P2P como una solución complementaria a las soluciones tradicionales de multicast IP. Reservando el uso de P2P para los canales de TV poco populares, se permite explotar los recursos de los equipos y se previene la necesidad de un alto número de árboles multicast dispersos. Como trabajo futuro, se propone refinar los algoritmos del AS, abordar diferentes escenarios experimentales y también extender las lecciones aprendidas en esta tesis a otros sistemas no basados en IMS

    Technological trampolines for new venture creation in Catalonia : the case of the University of Girona

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    Recent trends in technology transfer show an intensification of spin-off creation as a modality of university research commercialisation, complementary to the conventional ones, contract research and licensing. In this paper we analyse the evolution, objectives, resources and activities of a specialised unit -Technological Trampoline (TT) - in charge of new venture creation at the University of Girona (Catalonia-Spain). Based on two theoretical frameworks, Resource-based-view and Institutional Theory, we adopt a multi-dimensional approach to study the strategy of spinning-off new ventures at the University of Girona in terms of resources and activities, how this process is organised and if the outputs fit with this UdG's objectives and the local environment. Our main contribution is an in-depth analysis of the spin-off creation unit with special emphasis on its variety of resources and activities. The results have a series of implications and recommendations at both university and TT level
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