109,151 research outputs found

    The relationship between local loop unbundling and the deployment of alternative broadband networks: An empirical analysis

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    This paper means to add to empirical research on the impact of local loop unbundling (LLU) on broadband networks. In particular, it focuses on broadband investment made by entrants. Starting from late Nineties telecommunications incumbents of several European Union countries have been required to unbundle their local loops. While there is a general consensus on the negative or null impact of unbundling obligations on incumbents' investment, research on the relationship between LLU and new entrants' investment, albeit growing, has not yet reached a coherent body of results. We have tested two propositions. First, service-based entry, which relies on LLU, paves the way to new entrants' subsequent investment in broadband systems (i.e. ladder of investment theory). Second, the price charged for local loop should increase over time in order to have a significant investment in alternative platforms (i.e. the transitory entry assistance theory). The empirical analysis is carried out on a sample of 27 European countries (2002-2009 period). We have collected country-level data on broadband lines and LLU policy indicators. The preliminary results suggest that service-based entry does not lead entrants to a subsequent facility-based entry, casting some doubts on the ladder of investment theory. The short ladder version of the theory has received confirmation instead. At the same time, an increasing price of local loop is not found to stimulate the entrants' investment in alternative broadband networks. --investment,competition,access regulation,broadband networks,unbundling local loop

    Time--space harmonic polynomials relative to a L\'{e}vy process

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    In this work, we give a closed form and a recurrence relation for a family of time--space harmonic polynomials relative to a L\'{e}vy process. We also state the relationship with the Kailath--Segall (orthogonal) polynomials associated to the process.Comment: Published in at http://dx.doi.org/10.3150/07-BEJ6173 the Bernoulli (http://isi.cbs.nl/bernoulli/) by the International Statistical Institute/Bernoulli Society (http://isi.cbs.nl/BS/bshome.htm

    Contribution to Local Landscape Units definition in OTALEX II

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    OTALEX II is the Territorial and Environmental Observatory of Alentejo (Portugal) and Extremadura (Spain), co-financed by POCTEP, developed with the cross-border collaboration of several Portuguese and Spanish bodies. It is composed of a Spatial Data Infrastructure (SDI) created in 2007, SDI-OTALEX (www.ideotalex.eu), which is an exchange platform for geographic information and Webmapping services among project partners. The integration of environmental indicators such as landscape indicators, for the characterization and monitoring of the Alentejo Extremadura area is one of the most relevant components of the project. This paper reports the achievements in defining Local Landscape Units (LLU) for a pilot area of Central Alentejo – the Pardiela river basin. The methodological approach applied Geographic Information System tools to integrate soils, geomorphology and land cover. The land cover map applies the CORINE Land Cover Legend Level 5 to Central Alentejo at a scale of 1 : 10,000. This map contains variables related to vegetation, hydrology (streams and water bodies) and human settlements (buildings, equipment, roads). The validation of the results obtained for LLU with previously defined Landscape Units and potential vegetation mapping confirm the reliability and replicability of the present methodology for similar territories

    Cultura i ciència a l´era de la llum

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    Cultura i ciència a l´era de la llu

    The relationship between local loop unbundling and the deployment of alternative broadband networks: An empirical analysis

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    This paper means to add to empirical research on the impact of local loop unbundling (LLU) on broadband networks. In particular, it focuses on broadband investment made by entrants. Starting from late Nineties telecommunications incumbents of several European Union countries have been required to unbundle their local loops. While there is a general consensus on the negative or null impact of unbundling obligations on incumbents' investment, research on the relationship between LLU and new entrants' investment, albeit growing, has not yet reached a coherent body of results. We have tested two propositions. First, service-based entry, which relies on LLU, paves the way to new entrants' subsequent investment in broadband systems (i.e. ladder of investment theory). Second, the price charged for local loop should increase over time in order to have a significant investment in alternative platforms (i.e. the transitory entry assistance theory). The empirical analysis is carried out on a sample of 27 European countries (2002-2009 period). We have collected country-level data on broadband lines and LLU policy indicators. The preliminary results suggest that service-based entry does not lead entrants to a subsequent facility-based entry, casting some doubts on the ladder of investment theory. The short ladder version of the theory has received confirmation instead. At the same time, an increasing price of local loop is not found to stimulate the entrants' investment in alternative broadband networks

    Menorca entre dos segles

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    L’illa de Menorca de l'Arxiduc Lluís Salvador d'Àustria, avu

    The influence of local loop unbundling on investment by incumbent telecommunications operators in the OECD member countries

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    This paper examines the influence of local loop unbundling (LLU) on incumbent telecommunications operators' investment in their respective telecommunications networks in OECD countries. In addition, the background of the influence is analyzed from both qualitatie and quantitative aspects. The study uses panel data (1995-2011) of capital expenditure(capex) and revenues to derive an investment function. The results indicate that LLU had a positive impact on investment by incumbent telecommunications operators in the United States, but a negative impact in Japan. These results echo those of previous empirical studies, which indicate that LLU can impact investment in various ways

    Latvijas iekšējais tirgus un produktu kvalitāte

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    Zinātnisko rakstu krājumā apkopotas Latvijas Universitātes Tirgvedības un kvalitātes vadības institūta un LLU Pārtikas tehnoloģijas fakultātes speciālistu pēdējo pētījumu atziņas uztura zinātnē

    A Regularization Term Based on a Discrete Total Variation for Mathematical Image Processing

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    In this paper, a new regularization term is proposed to solve mathematical image problems. By using difference operators in the four directions; horizontal, vertical and two diagonal directions, an estimation of derivative amplitude is found. Based on the new obtained estimation, a new regularization term will be defined, which can be viewed as a new discretized total variation (TVprn) model. By improving TVprn, a more effective regularization term is introduced. By finding conjugate of TVprn and producing vector fields with special constraints, a new discretized TV for two dimensional discrete functions is proposed (TVnew). The capability of the new TV model to solve mathematical image problems is examined in some numerical experiments. It is shown that the new proposed TV model can reconstruct the edges and corners of the noisy images better than other TVs. Moreover, two test experiments of resolution enhancement problem are solved and compared with some other different TVs

    A Machine learning approach to POS tagging

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    We have applied inductive learning of statistical decision trees and relaxation labelling to the Natural Language Processing (NLP) task of morphosyntactic disambiguation (Part Of Speech Tagging). The learning process is supervised and obtains a language model oriented to resolve POS ambiguities. This model consists of a set of statistical decision trees expressing distribution of tags and words in some relevant contexts. The acquired language models are complete enough to be directly used as sets of POS disambiguation rules, and include more complex contextual information than simple collections of n-grams usually used in statistical taggers. We have implemented a quite simple and fast tagger that has been tested and evaluated on the Wall Street Journal (WSJ) corpus with a remarkable accuracy. However, better results can be obtained by translating the trees into rules to feed a flexible relaxation labelling based tagger. In this direction we describe a tagger which is able to use information of any kind (n-grams, automatically acquired constraints, linguistically motivated manually written constraints, etc.), and in particular to incorporate the machine learned decision trees. Simultaneously, we address the problem of tagging when only small training material is available, which is crucial in any process of constructing, from scratch, an annotated corpus. We show that quite high accuracy can be achieved with our system in this situation.Postprint (published version
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