506,475 research outputs found

    Challenges of digital innovations : a set-top box based approach

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    The chapter analyses the challenges of digital technology for television audience measurement systems. First, the current state of audience measurement in Belgium is described. In the Belgian case, the traditional television audience measurement system is contested by small broadcasters and challenged by the opportunities that the emergence of digital television and, more specifically, the widespread diffusion of set-top boxes provide. Second, three major challenges for traditional measurement techniques are analysed. This section deals with people’s changing viewing habits, for example on-demand and time-shifted viewing, the provision of more accurate data by set-top boxes, and the increasing interests of platform operators acting as gatekeepers to access to this data. In the final section, conclusions are made

    On the global economic potentials and marginal costs of non-renewable resources and the price of energy commodities

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    A model is presented in this work for simulating endogenously the evolution of the marginal costs of production of energy carriers from non-renewable resources, their consumption, depletion pathways and timescales. Such marginal costs can be used to simulate the long term average price formation of energy commodities. Drawing on previous work where a global database of energy resource economic potentials was constructed, this work uses cost distributions of non-renewable resources in order to evaluate global flows of energy commodities. A mathematical framework is given to calculate endogenous flows of energy resources given an exogenous commodity price path. This framework can be used in reverse in order to calculate an exogenous marginal cost of production of energy carriers given an exogenous carrier demand. Using rigid price inelastic assumptions independent of the economy, these two approaches generate limiting scenarios that depict extreme use of natural resources. This is useful to characterise the current state and possible uses of remaining non-renewable resources such as fossil fuels and natural uranium. The theory is however designed for use within economic or technology models that allow technology substitutions. In this work, it is implemented in the global power sector model FTT:Power. Policy implications are given.Comment: 18 pages, 7 figures, 8 pages of supplementary informatio

    Report of the direct infrared sensors panel

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    The direct infrared sensors panel considered a wide range of options for technologies relevant to the science goals of the Astrotech 21 mission set. Among the technologies assessed are: large format arrays; photon counting detectors; higher temperature 1 to 10 micro-m arrays; impurity band conduction (IBC) or blocked impurity band (BIB) detectors; readout electronics; and adapting the Space Infrared Telescope Facility and Hubble Space Telescope. Detailed development plans were presented for each of these technology areas

    Report of the ultraviolet and visible sensors panel

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    In order to meet the science objectives of the Astrotech 21 mission set the Ultraviolet (UV) and Visible Sensors Panel made a number of recommendations. In the UV wavelength range of 0.01 to 0.3 micro-m the focus is on the need for large format high quantum efficiency, radiation hard 'solar-blind' detectors. Options recommended for support include Si and non-Si charge coupled devices (CCDs) as well as photocathodes with improved microchannel plate readouts. For the 0.3 to 0.9 micro-m range, it was felt that Si CCDs offer the best option for high quantum efficiencies at these wavelengths. In the 0.9 to 2.5 micro-m the panel recommended support for the investigation of monolithic arrays. Finally, the panel noted that the implementation of very large arrays will require new data transmission, data recording, and data handling technologies

    Galaxy And Mass Assembly (GAMA) : galaxy close pairs, mergers and the future fate of stellar mass

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    ASGR acknowledges STFC and SUPA funding that were used to do this work. GAMA is funded by the STFC (UK), the ARC (Australia), the AAO and the participating institutions.We use a highly complete subset of the Galaxy And Mass Assembly II (GAMA-II) redshift sample to fully describe the stellar mass dependence of close pairs and mergers between 10(8) and 10(12)M(circle dot). Using the analytic form of this fit we investigate the total stellar mass accreting on to more massive galaxies across all mass ratios. Depending on how conservatively we select our robust merging systems, the fraction of mass merging on to more massive companions is 2.0-5.6 per cent. Using the GAMA-II data we see no significant evidence for a change in the close pair fraction between redshift z = 0.05 and 0.2. However, we find a systematically higher fraction of galaxies in similar mass close pairs compared to published results over a similar redshift baseline. Using a compendium of data and the function gamma(M) = A(1 + z)(m) to predict the major close pair fraction, we find fitting parameters of A = 0.021 +/- 0.001 and m = 1.53 +/- 0.08, which represents a higher low-redshift normalization and shallower power-law slope than recent literature values. We find that the relative importance of in situ star formation versus galaxy merging is inversely correlated, with star formation dominating the addition of stellar material below M* and merger accretion events dominating beyond M*. We find mergers have a measurable impact on the whole extent of the galaxy stellar mass function (GSMF), manifest as a deepening of the 'dip' in the GSMF over the next similar to Gyr and an increase in M* by as much as 0.01-0.05 dex.Publisher PDFPeer reviewe

    Radiative models for jets in X-ray binaries

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    In this work we develop a lepto-hadronic model for the electromagnetic radiation from jets in microquasars with low-mass companion stars. We present general results as well as applications to some specific systems, and carefully analyze the predictions of the model in the gamma-ray band. The results will be directly tested in the near future with the present and forthcoming space-borne and terrestrial gamma-ray telescopes.Comment: 10 pages, 6 figures. Short summary of the main results of the author's PhD Thesis. The full text of the thesis is available for download at http://fcaglp.unlp.edu.ar/~gvila/thesi

    Balancing and integrating basic values in the development of organic regulations and standards: proposal for a procedure using case studies of conflicting areas

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    The basic aim of the report is to develop a procedure for the integration of the ethical value base of organic farming into standards and regulations. For this it is necessary to identify the core ethical value of organic production, consider their coherence and relate them to existing practice of organic food and farming. Ethical values are per se in need of interpretation. It is therefore also necessary to consider the process of decision-making, when aiming to achieve a coherent integration of such values in the structure of a standard or regulation. In line with the European Action Plan for organic food and farming from 2004 the Project EEC 2092/91 (Organic) Revision supports the idea that delegating a larger role to values and basic principles will help to harmonise the rules, provide room for flexibility in implementation and to simplify the European Regulation for organic production. It is important to include basic values in standards and regulations, because organic farming is value based and all actors/stakeholders have value expectations, including consumers who the regulation wants to protect. Standards and regulations form the basis of a virtual contract between the consumer and the producers. By following the practices set out in the standards, producers give a promise to the consumer to deliver on additional ethical values, beyond the legal minimum standards for conventional agriculture and food. The growing and globalised organic market and the involvement of large companies have resulted in renewed interest in the values and principles of organic farming. There has been concern that the organic food and farming sector is becoming more conventionalised, and has lost touch with its basic values. Thus it will no longer function effectively as a real alternative to general agriculture for consumers, producers and also for policy makers. The report analyses what core ethical value are associated with organic agriculture and should therefore be considered for inclusion in a regulation. This value base is contrasted with the existing Regulation (EEC) 2092/91 and with examples of current practice of organic agriculture in Europe. The implications of including ethical values in the structure of a regulation for decisionmaking are considered. Following on from the European Action Plan a process of total revision of the EU regulation on organic production is underway. A new European Regulation for organic production was adopted by the European Council of Ministers in June 2006 and will come into force in Jan 2009. The text of the near final proposal from December 2006 has been considered in several sections of the report. The report finishes with some conclusions and recommendations for the EU Commission and other standard setting bodies regarding the choice and roles of values in organic standard, the rules for decision-making processes in relation to integrating values, and regarding the ongoing revision of the organic regulation in Europe

    Simulating Postbuckling Behaviour and Collapse of Stiffened CFRP Panels

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    Advanced composite materials are well known for their outstanding potential in weight-related stiffness and strength leading to an ever increasing share in aerospace structural components out of Carbon Fibre Reinforced Plastics (CFRP). In order to fully exploit the load-carrying capacity of such structures an accurate and reliable simulation is indispensable. Local buckling is not necessarily the load bearing limit for stiffened panels or shells; their full potential can be tapped only by utilizing the postbuckling region. That, however, requires fast tools which are capable of simulating the structural behaviour beyond bifurcation points including material degradation up to collapse. The most critical structural degradation mode is skin stringer separation; delamination, especially within the stringer, is a critical material degradation. A reliable prediction of collapse requires knowledge of degradation due to static as well as low cycle loading in the postbuckling region. Earlier projects have shown that it needs considerable experience in simulating the postbuckling behaviour. Though a great deal of knowledge about CFRP structural and material degradation is available its influence on collapse is not yet sufficiently investigated. It is the aim of the project COCOMAT (Improved MATerial exploitation at safe design of COmposite airframe structures by accurate simulation of COllapse) to develop means for and gain experience in fast and accurate simulation of the collapse load of stringer stiffened CFRP curved panels taking degradation and cyclic loading as well as geometric nonlinearity into account. COCOMAT is a Specific Targeted Research Project supported by the EU 6th Framework Programme; it started 2004 and runs for 4 years. Main deliverables are: • test results for buckling and collapse of undamaged and pre-damaged stiffened CFRP panels under static and cyclic loading, • improved material properties and degradation models, computational tools for design and certification of stiffened fibre composite panels which take postbuckling behaviour, degradation and collapse into account, • and finally design guidelines and industrial validation. The work will lead to an extended experimental data base, relevant degradation models and improved simulation tools for certification as well as for design. These results should allow setting up a future design scenario which exploits the existing reserves in primary fibre composite structures. The paper starts out from results provided by the forerunners of COCOMAT, describes the main objectives of the project, gives a general status of the progress reached so far and presents first results

    Technology and skills in the construction industry

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    Experimental Study on an Electrical Deicing Technology Utilizing Carbon Fiber Tape

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