796 resultados para Empirical Algorithm Analysis
Resumo:
The Spanish transition from dictatorship to democracy is often described as an example of negotiation or agreement between the elites (Sánchez Cuenca and Aguilar, 2009: 433). Journalistic and political elites, aware of their important historical role, agreed a consensus on certain issues (democracy, constitution, amnesty) or characters (King Juan Carlos I), in order to ensure the stability of the democratic process (Zugasti, 2007, 2008). Television, which articulates the discourse of the masses, has been one of the basic means used to illustrate the development. Among the highlights of recent major audiovisual content, Cuéntame cómo pasó (2001-present) -a TV-series designed to explain changes with a nostalgic tone in Spanish society since 1968 until today- stands out. By choosing a random sample of episodes for this research we propose to verify the validity of the representation of the political process which contextualizes the series. By analyzing many elements, such as the opinions of the main characters, their personal, political and geographical situations, we try to show the construction of a focal point that sanctifies the official version. We also stress the pacifying and nostalgic tone, which constructs stereotypes and taboos about the process and which characterizes this series as a symbolic culmination of the democratization undertaken by the elites.
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The Lomb periodogram has been traditionally a tool that allows us to elucidate if a frequency turns out to be important for explaining the behaviour of a given time series. Many linear and nonlinear reiterative harmonic processes that are used for studying the spectral content of a time series take into account this periodogram in order to avoid including spurious frequencies in their models due to the leakage problem of energy from one frequency to others. However, the estimation of the periodogram requires long computation time that makes the harmonic analysis slower when we deal with certain time series. Here we propose an algorithm that accelerates the extraction of the most remarkable frequencies from the periodogram, avoiding its whole estimation of the harmonic process at each iteration. This algorithm allows the user to perform a specific analysis of a given scalar time series. As a result, we obtain a functional model made of (1) a trend component, (2) a linear combination of Fourier terms, and (3) the so-called mixed secular terms by reducing the computation time of the estimation of the periodogram.
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The Iterative Closest Point algorithm (ICP) is commonly used in engineering applications to solve the rigid registration problem of partially overlapped point sets which are pre-aligned with a coarse estimate of their relative positions. This iterative algorithm is applied in many areas such as the medicine for volumetric reconstruction of tomography data, in robotics to reconstruct surfaces or scenes using range sensor information, in industrial systems for quality control of manufactured objects or even in biology to study the structure and folding of proteins. One of the algorithm’s main problems is its high computational complexity (quadratic in the number of points with the non-optimized original variant) in a context where high density point sets, acquired by high resolution scanners, are processed. Many variants have been proposed in the literature whose goal is the performance improvement either by reducing the number of points or the required iterations or even enhancing the complexity of the most expensive phase: the closest neighbor search. In spite of decreasing its complexity, some of the variants tend to have a negative impact on the final registration precision or the convergence domain thus limiting the possible application scenarios. The goal of this work is the improvement of the algorithm’s computational cost so that a wider range of computationally demanding problems from among the ones described before can be addressed. For that purpose, an experimental and mathematical convergence analysis and validation of point-to-point distance metrics has been performed taking into account those distances with lower computational cost than the Euclidean one, which is used as the de facto standard for the algorithm’s implementations in the literature. In that analysis, the functioning of the algorithm in diverse topological spaces, characterized by different metrics, has been studied to check the convergence, efficacy and cost of the method in order to determine the one which offers the best results. Given that the distance calculation represents a significant part of the whole set of computations performed by the algorithm, it is expected that any reduction of that operation affects significantly and positively the overall performance of the method. As a result, a performance improvement has been achieved by the application of those reduced cost metrics whose quality in terms of convergence and error has been analyzed and validated experimentally as comparable with respect to the Euclidean distance using a heterogeneous set of objects, scenarios and initial situations.
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Mixed enterprises, which are entities jointly owned by the public and private sector, are spreading all over Europe in local utilities. Well aware that in the vast majority of cases the preference of local authorities towards such governance structure is determined by practical reasons rather than by the ambition to implement new regulatory designs (an alternative to the typical “external” regulation), our purpose is to confer some scientific value to this phenomenon which has not been sufficiently investigated in the economic literature. This paper aims at proposing an economic analysis of mixed enterprises, especially of the specific configuration in which the public partner acts as controller and the private one (or “industrial” partner) as service provider. We suggest that the public service concession to mixed enterprises could embody, under certain conditions, a noteworthy substitute to the traditional public provision and the concession to totally private enterprises, as it can push regulated operators to outperform and limit the risk of private opportunism. The starting point of the entire analysis is that ownership allows the (public) owner to gather more information about the actual management of the firm, according to property rights theory. Following this stream of research, we conclude that under certain conditions mixed enterprises could significantly reduce asymmetric information between regulators and regulated firms by implementing a sort of “internal” regulation. With more information, in effect, the public authority (as owner/controller of the regulated firm, but also as member of the regulatory agency) can stimulate the private operator to be more efficient and can monitor it more effectively with respect to the fulfilment of contractual obligations (i.e., public service obligations, quality standards, etc.). Moreover, concerning the latter function, the board of directors of the mixed enterprise can be the suitable place where public and private representatives (respectively, welfare and profit maximisers) can meet to solve all disputes arising from incomplete contracts, without recourse to third parties. Finally, taking into account that a disproportionate public intervention in the “private” administration (or an ineffective protection of the general interest) would imply too many drawbacks, we draw some policy implications that make an equitable debate on the board of the firm feasible. Some empirical evidence is taken from the Italian water sector.
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State aid for rescue and restructuring (R&R) of companies in difficulty causes a significant distortion of competition. It prevents the market from eliminating inefficient companies. Because of this, the European Commission has to be specially strict when it assesses rescue or restructuring aid. This paper examines recent cases of corporate restructuring partly funded with public money. It explains the main aspects of the current guidelines which are applicable to R&R State Aid and establishes a theoretical framework for the economic assessment of R&R aid. It then analyses decisions adopted by the European Commission concerning R&R state aid during the period 2000-2013. It finds that there is little economic rationale in the granting of R&R aid. The paper concludes by applying the lessons drawn from the empirical analysis to the anticipated revision of the R&R guidelines in the context of the State Aid Modernisation process.
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An increasing number of bilateral or plurilateral trade agreements (or regional trade agreements: RTAs) include "labor clauses" that require or urge the signatory countries to commit to maintaining a certain level of labor standards. This paper performs an empirical analysis of the impacts of such labor clauses provided in RTAs on working conditions that laborers in the RTA signatory countries actually face, using macro-level data for a wide variety of countries. The paper first examines the texts of labor provisions in more than 220 effective RTAs and (re-)classifies "RTAs with labor clauses" according to two criteria: (i) the agreement urges or expects the signatory countries to harmonize their domestic labor standards with internationally recognized standards, and (ii) the agreement stipulates the procedures for consultations and/or dispute settlement on labor-condition issues between the signatory countries. Based on this labor-clause RTA classification, the paper estimates the impacts of RTA labor clauses on working conditions in countries with two empirical specifications using the sample covering 136 countries or economies and years from 1995 through 2011. The estimation is extended to takes into account possible lags in the labor-condition effects of labor clauses as well as to consider potential difference in the impacts for countries in different income levels. The empirical results for the four measures of labor conditions (mean monthly real earnings, mean weekly work hours per employee, fatal occupational injury rate, and the number of the ILO's Core Conventions ratified) find no evidence for possible pro-labor-condition effects of RTA labor clauses overall, which should be consistent with the view of economics literature that questions the relevance of linking trade policy with issues in the domestic labor standards.
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Bibliographical references in "Statistical sources and methods of computation" (p.[141]-162.)
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"Unclassified"--Cover.
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Includes bibliographic references (page 13).
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"DOT/RSPA/DMA-50/83/19."
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Includes bibliographical references.
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"This project was supported by the Office of Policy Planning and Research, LMSA/PWBP, U.S. Department of Labor under Contract No. J-9-P-9-0175."
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Includes bibliographical references (p. 17).
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Bibliography: p. 20.
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Bibliography: leaf 25.