Efficient memory management in video on demand servers

In this article we present, analyse and evaluate a new memory management technique for video-on-demand servers. Our proposal, Memory Reservation Per Storage Device (MRPSD), relies on the allocation of a fixed, small number of memory buffers per storage device. Selecting adequate scheduling algorithms, information storage strategies and admission control mechanisms, we demonstrate that MRPSD is suited for the deterministic service of variable bit rate streams to intolerant clients. MRPSD allows large memory savings compared to traditional memory management techniques, based on the allocation of a certain amount of memory per client served, without a significant performance penaltyPublicad

ALGORITHM TO EXTRACT MODEL PARAMETERS OF PARTIALLY SHADED PHOTOVOLTAIC MODULES

Uneven irradiation, due to partial shading, can produce hot spots in photovoltaic modules. A classical solution to avoid hot spot consists in using bypass diodes in antiparallel to series-connected cell groups. This solution brings a new problem: the presence of multiple local maximum power points. We present a simple algorithm for fast extraction of the model parameters of partially shaded photovoltaic panels with bypass diodes. An example of the application of the proposed algorithm is illustrated using the data from a real monocrystalline silicon technology photovoltaic module measured under uniform illumination and partial shading conditions. The possibility of using the algorithm as a practical approximate solution is also discussed. The simulations, using only four parameters, represent reasonably well the measured data

Presentation of the paper “Definition of a Technological Ecosystem for Scientific Knowledge Management in a PhD Programme”

[EN]This is the presentation of the paper entitled “Definition of a Technological Ecosystem for Scientific Knowledge Management in a PhD Programme” in the TEEM 2015 International Conference held in Porto (Portugal) in October 7-9, 2015

Knowledge Management and decision making based on informal learning activities in business

The application of the Information and Communication Technologies to everyday life activities facilitates the availability of lots of information and knowledge which can be used for multiple purposes. One of them is learning processes within organizations. However, there are two questions which must be addressed: first, that people do not only learn in organizational contexts; and second, that not all the data gathered from learning systems is useful. This makes it necessary to find a way to gather information about informal learning activities in the workplace and to facilitate visibility of what employees learn outside the organization so that such knowledge may be accessed from within the organization and be used for decision making. In order to do so this study proposes a methodology based on the identification of informal learning instances by the employee and their ecognition by the organization. The methodology is supported by a technological framework based on a Personal Learning Network, a Portfolio, a Catalog of Competences and an institutional system which includes tools for optimization of decision making. The methodology has been implemented and evaluated in the context of a pan-European project. The main findings from this study suggest that, although decision making from informal learning instances is possible, both the methodology and tools used should be flexible enough to satisfy the needs of the organization

Determination of faecal dry matter digestibility two weeks after weaning in twenty five day old weaned rabbits

[EN] The aim of this work was to analyse the evolution from 26 to 40 d of age of apparent faecal dry matter digestibility (DMd) in rabbits weaned at 25 d of age to define how to determine nutrient digestibility in the post-weaning period. Fifteen New Zealand ' Californian rabbits from five litters (3 rabbits/litter) weaned at 25 d of age and weighing 602±75g were fed ad libitum a commercial diet containing 20.0% crude protein and 33.5% NDF (on DM basis). Feed intake and faeces excretion were recorded daily from 25 to 40 d of age and DM digestibility determined. Litter affected DM intake and excretion (P = 0.013 and 0.014, respectively), and tended to affect DMd (P = 0.061), whereas age influenced all these traits (P < 0.001). Dry matter intake and DM excretion increased from 26 to 40 d of age by 158 and 480%, respectively. During the first week after weaning, DM intake increased more slowly than DM excretion (55 vs. 245%), but in the second week after weaning both increased by 67%. The correlation between daily feed intake was higher with the faeces excretion of the same day than with faeces excretion of the next day, and the first values were used to determine daily DMd. A broken line regression model was fitted to daily DMd, which decreased linearly from weaning to 32 d of age (2.17 ± 0.25 percentage units per day), whereas from 32 to 40 d it remained constant (69.4 ± 0.47%). Accordingly, for 25-d old weaned rabbits it would be advisable to begin a digestibility trial not before 32 d of age, using the first week after weaning as adaptation period. Average standard deviation of DMd decreased by 54% when the length of the collection period increased from 2 to 6 d. Consequently, the number of animals required to detect a significant difference among means depends on the length of the collection period. For a conventional collection period of four days, a difference of 2 percentage units could be detected by using 14 animals/treatment.Gómez-Conde, M.; García, J.; Villamide, M.; Carabaño, R. (2011). Determination of faecal dry matter digestibility two weeks after weaning in twenty five day old weaned rabbits. World Rabbit Science. 19(1):43-48. doi:10.4995/wrs.2011.816SWORD434819

Delphi study to identify the young people priorities about digital society

!is paper aims to present an advance of the results of the application of the Delphi technique, with the aim of gathering the opinion of experts or stakeholders on the topics of priority interest of young people in Europe, especially on the digital society. It is a work framed within the Horizon 2020 WYRED Project (netWorked Youth Research for Empowerment in the Digital Society). !e WYRED project, and in this specific case the Networking process, aims in bringing together children, young people, other stakeholders and policymakers around Europe. !e Delphi technique is one of the prospective methods that study the future, concerning the evolution of the factors of the technosocio- economic environment and the interactions between these factors. !e characteristics that define this technique are anonymity, iteration and controlled feedback, and presentation of group data in the statistical form. !e progress of the presented results allows us to corroborate the agreement of experts about the topics that have been raised. According to experts, the concern of youth towards issues related to the digital society does not appear among the first concerns of young people neither in Spain nor the rest of the countries surveyed

Moodle HEODAR implementation and its implantation in an academic context.

[EN]One of the most important aspects of a 'continuously in change’ society is to improve everything everywhere. In order to obtain the best products, they should be periodically evaluated and reengineered. So the evaluation task and of course, the adequate results interpretation, can make all the difference between competitors. E-learning is similar to these products. Different issues can be evaluated to make learning process getting better and better, such as tutors, platform software and contents. In this last issue, it can be included the minimum knowledge unit: the learning object (LO) (De Marcos et al., 2008). There exist different models and methods for LO evaluation. What is pretended with this work is to choose one model and implement a singular tool, in order to automatically evaluate these LOs and produce a set of information, that can be used to improve those LOs. In this case, it is implemented in the evaluation model called HEODAR (Morales et al., 2008a) and after that the model is implanted in Studium, the Moodle campus of Salamanca University

Questionnaire to measure Educational Technologies Acceptance in Moroccan Public Universities

[EN]The project “Support to the Higher Education system in Morocco within the framework of a rapprochement with the European Higher Education Area” (Appui au Système de l'Enseignement supérieur au Maroc dans le cadre d'un rapprochement avec l'Espace européen de l'Enseignem), is an European Project whose general objective is accompanying, assisting and promoting the reform of the Moroccan higher education system within the framework of its strategic vision 2015-2030 and its approach to the European Higher Education Area in order to improve the employability of graduates and the governance of the university system. The project is organized into 6 components that involve different Spanish institutions. In the development of Component 3 (Mission 3.1), Diversification des modalités d’enseignement (stratégie e-learning), it is important to know the perception and opinion of teachers from Moroccan public universities related to the state, use and prospection of educational technologies (García-Peñalvo, 2018; García-Peñalvo & Seoane-Pardo, 2015; Gros & García-Peñalvo, 2016) in their teaching activity. To achieve this objective, a questionnaire based on the extended (Huang, Teo, Sánchez-Prieto, García-Peñalvo, & Olmos-Migueláñez, 2019; Sánchez-Prieto, 2018; Sánchez-Prieto, Hernández-García, García-Peñalvo, Chaparro- Peláez, & Olmos-Migueláñez, 2019; Sánchez-Prieto, Olmos-Migueláñez, & García-Peñalvo, 2016a, 2016b, 2017; Venkatesh & Bala, 2008) TAM model has been designed (Technology Acceptance Model). Thus, an evaluation model is proposed in which, in addition to evaluating the 3 usual dimensions of the TAM models (perceived utility, perceived facility, behavioural intention), 7 external dimensions are included related to social influence (Subjective norm; Social image), the professional context (Voluntariness, relevance, results of use, external control of the tool) and the personal context (Anxiety)

Questionnaire on Indicators of Incorporation and Use of Educational Technologies in Moroccan Public Universities

[EN]The project “Support to the Higher Education system in Morocco within the framework of a rapprochement with the European Higher Education Area” (Appui au Système de l'Enseignement supérieur au Maroc dans le cadre d'un rapprochement avec l'Espace européen de l'Enseignem), is an European Project whose general objective is accompanying, assisting and promoting the reform of the Moroccan higher education system within the framework of its strategic vision 2015-2030 and its approach to the European Higher Education Area in order to improve the employability of graduates and the governance of the university system. The project is organized into 6 components that involve different Spanish institutions. In the development of component 3 (Mission 3.1), Diversification des modalités d’enseignement (stratégie eLearning), it is important to have a basic knowledge of some indicators on the incorporation and use of educational technologies In Moroccan Public Universities. To this end, we present in the framework of this project a simple questionnaire, which each public university must answer separately. In this sense, it is important that the answers reflect the reality of each institution in the most reliable way possible. The data collected aimed to facilitate, on the one hand, the making of recommendations by the panel of experts of this Component 3. On the other hand, the information collected aims to guide the decision making in the use of educational technologies and in the definition of an eLearning strategy (García- Peñalvo & Seoane-Pardo, 2015; Gros & García-Peñalvo, 2016) in the Moroccan Public University System, both at the ministerial level and individually by the heads of the Moroccan Public Universities. The UNIVERSITIC reports (CRUE TIC, 2014; Gómez, 2016, 2018; Píriz, 2015), made by CRUE Universidades Españolas, have been taken as reference for the realization of this questionnaire http://www.crue.org/SitePages/Universitic.aspx