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Gmez-Prez J.M.,Intelligent Software Components ISOCO S.A. | Erdmann M.,Ontoprise GmbH | Greaves M.,Vulcan Inc. | Corcho O.,Technical University of Madrid | Benjamins R.,Telefnica ID
International Journal of Human Computer Studies | Year: 2010

The development of knowledge-based systems is usually approached through the combined skills of software and knowledge engineers (SEs and KEs, respectively) and of subject matter experts (SMEs). One of the most critical steps in this task aims at transferring knowledge from SMEs' expertise to formal, machine-readable representations, which allow systems to reason with such knowledge. However, this process is costly and error prone. Alleviating such knowledge acquisition bottleneck requires enabling SMEs with the means to produce the target knowledge representations, minimizing the intervention of KEs. This is especially difficult in the case of complex knowledge types like processes. The analysis of scientific domains like Biology, Chemistry, and Physics uncovers: (i) that process knowledge is the single most frequent type of knowledge occurring in such domains and (ii) specific solutions need to be devised in order to allow SMEs to represent it in a computational form. We present a framework and computer system for the acquisition and representation of process knowledge in scientific domains by SMEs. We propose methods and techniques to enable SMEs to acquire process knowledge from the domains, to formally represent it, and to reason about it. We have developed an abstract process metamodel and a library of problem solving methods (PSMs), which support these tasks, respectively providing the terminology for SME-tailored process diagrams and an abstract formalization of the strategies needed for reasoning about processes. We have implemented this approach as part of the DarkMatter system and formally evaluated it in the context of the intermediate evaluation of Project Halo, an initiative aiming at the creation of question answering systems by SMEs. © 2010 Elsevier Ltd. All rights reserved. Source


Artundo I.,Polytechnic University of Valencia | Tymecki A.,Orange S.A. | Ortego E.,Telefnica ID | Ortega B.,Polytechnic University of Valencia
Optical Fiber Technology | Year: 2011

To analyze the costs of deploying any optical fiber network, it is critical to know the evolution of prices of its individual components in time. In this paper we investigate on the pricing and installation costs of several passive optical components, focusing as an example on optical fiber connectors, and present reliable data price trends for them. We then propose future costs based on parametric methods and the application of the extended learning curve model. The key contributions of this analysis are the accurate learning coefficients extracted for each type of optical component, ranging from 0.66 to 0.96 for fiber connectors or 0.88 for fiber cables, which can serve as valuable inputs to more complex, higher-level techno-economical models. Large price drops of 33% for splitters and 78% for attenuators have been also identified with these methods for the following years. © 2011 Elsevier Inc. All rights reserved. Source


Kiss Kallo C.,Intune Networks | Shields J.,Intune Networks | O'Malley C.,Intune Networks | Carley R.,Intune Networks | And 2 more authors.
2012 16th International Conference on Optical Networking Design and Modelling, ONDM 2012 | Year: 2012

This paper summarises the modelling results obtained with a sub-wavelength optical packet switching technology, called OPST (Optical Packet Switch and Transport), when compared against an IPoDWDM solution. In particular, the impact of data centre location in the network on the network cost is studied for two architectures based on different technologies. Data centre location, routing strategies, service mix, traffic growth and subscriber service take-up is modelled to obtain a broad view about the cost sensitivities in these networks. The main contribution of the paper is to demonstrate that resilience to data centre location and changing traffic patterns enable the sub-wavelength packet optical solution to achieve cost savings of 150% when compared to the IPoDWDM approach. Such flexibility of the packet optical solution also enables 100-300% of power consumption cost reduction and an average 150% savings on rack cabinets for typical configurations. © 2012 IEEE. Source


Alvarez D.,Autonomous University of Madrid | Lopez V.,Autonomous University of Madrid | Anamuro J.L.,Autonomous University of Madrid | De Vergara J.L.,Autonomous University of Madrid | And 2 more authors.
2011 International Conference on the Network of the Future, NOF 2011 - Proceedings | Year: 2011

In recent years, Path Computation Element (PCE) architecture has been standardized as a suitable solution for path computation in multi-domain network scenarios. The Traffic Engineering Database (TED) of the PCE is updated with the information of the control plane. However, there is a delay from the PCE replies to a request, until the TED is updated with the network status information. This delay includes not only the control plane delay, but also Path Computation Element Protocol (PCEP) information exchange. This desynchronization in the TED and the real status information leads to an extra blocking situation when the Label Switch Router (LSR) tries to reserve a path, but it has been previously reserved by other LSR. To solve such problem, a recent draft is submitted to the IETF proposing new PCEP extensions for a pre-reservation of the computed path resources for a certain period. This work implements in C three multi-domain algorithms: Per-domain Path Computation, Backward-Recursive PCE-based Computation and Hierarchical Path Computation Element and it assesses their performance with and without mechanisms to reduce this extra blocking probability due to the uncertainty of the TED information. © 2011 IEEE. Source


De-Frutos-Lopez M.,Charles III University of Madrid | Orellana-Quiros D.,PRODYS S.L. | Pujol-Alcolado J.C.,Telefnica ID | Pujol-Alcolado J.C.,Charles III University of Madrid | Diaz-De-Maria F.,Charles III University of Madrid
Signal Processing: Image Communication | Year: 2010

In this article, an improved version of one of the most cited intra mode decision algorithms in H.264/AVC video coding is proposed with the aim to improve its efficiency and performance. The reference algorithm determines the interpolation/extrapolation spatial direction (mode) for achieving the best intra prediction using the Sobel gradient calculation. The proposed algorithm suggests reducing the number of gradients calculated and changing the Sobel operator to that of Roberts. In addition to this, it also proposes including the previously encoded neighboring block modes among the evaluated modes. Experimental results show that the proposed algorithm reduces the computational load of the original algorithm and substantially improves its rate-distortion performance. © 2010 Elsevier B.V. All rights reserved. Source

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