3,880 research outputs found

    PROPERTIES OF TWO U.S. INFLATION MEASURES (1985-2005)

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    Analyses are presented of 84 quarterly observations 1/85-4/05 on two U.S. index numbers of nominal prices often employed to measure inflation. Analyses are designed to answer two key questions of interest to macroeconomists. Is inflation stationary (I(0)) or stochastically non-stationary (I(1))? If it is I(1), is it scalar or multivariate? Both measures of inflation are found clearly to be I(1) and, for these measures, inflation is found clearly to be scalar. The paper also illustrates univariate analysis procedures (and report standards) considered to be more effective and convincing than those found in the existing literature on inflation measures.

    Information Misweighting and Stock Recommendations

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    I provide evidence that analysts whose earnings forecast revisions showed signs of greater exaggeration in the past make recommendation changes that lead to lower abnormal returns than their peers. Interpreting stock recommendations as a forecast of future abnormal returns, I show that this evidence is consistent with the hypothesis that analysts who typically exaggerate or overstate the weight of their private information when issuing forecasts also do so when making recommendations. I also show that past earnings forecast provide incremental information about analysts' recommending behavior beyond that contained in past recommendations.Information misweighting; stock recommendations; earnings forecasts; financial analysts

    Modelling hydrological connectivity in burned areas. A case study from South of Spain

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    Overland flow connectivity depends on the spatio-temporal interactions of hydrological and geomorphic processes as well as on the human footprint on the landscape. This study deals with the modelling of hydrological connectivity in a burned area with different levels of fire severity. Namely, the objectives are to: i) characterize and ii) modelling the pre- (PreF) and post-fire (PostF) scenarios, as well as iii) evaluate the effect of the vegetation changes due to the fire and the initial post-fire management practices (construction of new skid trails and check-dams) on the magnitude and spatial pattern of connectivity. Four post-fire scenarios are simulated: immediately after the fire (PostF1), with new skids and without check-dams (PostF2), with new skids and check-dams and without vegetation recovery (PostF3), and with new skids and check-dams and incipient vegetation cover (PostF4). The study area corresponds to eleven headwater sub-catchments (total area of 329 ha) that cover the entire burned area of the mountain in the West and Southwest facing hillslopes (ca. 200 ha). This site is located in the province of Malaga, South of Spain, and all sub-catchments are disconnected between them. The fire started in 2014, 27 June and lasted two days. The landscape is mainly mountainous, with very steep slopes and marble rocks, Mediterranean climate, and a land use of shrubs and pine forests (pre-fire scenario). Settlements appear at the bottom of the slopes. After the wildfire, land management were carried out in order to remove completely the burned trees and thus new skid trails were built. Then, eleven concrete check-dams and twelve wooded check-dams were built in the main gullies. The different scenarios of linear landscape elements, vegetation cover and modifications on the topography related to the construction of new trails and check-dams were included in the simulations. The IC index of hydrological connectivity was chosen to perform this metric at a spatial resolution of 5 x 5 meters. The analysis of the different spatial patterns and temporal changes was done considering the different levels of fire severity and changes on hydrological connectivity were also analysed at the outlet of each sub-catchment.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    Improved construction of irregular progressive edge-growth Tanner graphs

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    The progressive edge-growth algorithm is a well-known procedure to construct regular and irregular low-density parity-check codes. In this paper, we propose a modification of the original algorithm that improves the performance of these codes in the waterfall region when constructing codes complying with both, check and symbol node degree distributions. The proposed algorithm is thus interesting if a family of irregular codes with a complex check node degree distribution is used.Comment: 3 pages, 3 figure

    Blind Reconciliation

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    Information reconciliation is a crucial procedure in the classical post-processing of quantum key distribution (QKD). Poor reconciliation efficiency, revealing more information than strictly needed, may compromise the maximum attainable distance, while poor performance of the algorithm limits the practical throughput in a QKD device. Historically, reconciliation has been mainly done using close to minimal information disclosure but heavily interactive procedures, like Cascade, or using less efficient but also less interactive -just one message is exchanged- procedures, like the ones based in low-density parity-check (LDPC) codes. The price to pay in the LDPC case is that good efficiency is only attained for very long codes and in a very narrow range centered around the quantum bit error rate (QBER) that the code was designed to reconcile, thus forcing to have several codes if a broad range of QBER needs to be catered for. Real world implementations of these methods are thus very demanding, either on computational or communication resources or both, to the extent that the last generation of GHz clocked QKD systems are finding a bottleneck in the classical part. In order to produce compact, high performance and reliable QKD systems it would be highly desirable to remove these problems. Here we analyse the use of short-length LDPC codes in the information reconciliation context using a low interactivity, blind, protocol that avoids an a priori error rate estimation. We demonstrate that 2x10^3 bits length LDPC codes are suitable for blind reconciliation. Such codes are of high interest in practice, since they can be used for hardware implementations with very high throughput.Comment: 22 pages, 8 figure

    Untainted Puncturing for Irregular Low-Density Parity-Check Codes

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    Puncturing is a well-known coding technique widely used for constructing rate-compatible codes. In this paper, we consider the problem of puncturing low-density parity-check codes and propose a new algorithm for intentional puncturing. The algorithm is based on the puncturing of untainted symbols, i.e. nodes with no punctured symbols within their neighboring set. It is shown that the algorithm proposed here performs better than previous proposals for a range of coding rates and short proportions of punctured symbols.Comment: 4 pages, 3 figure

    Rate Compatible Protocol for Information Reconciliation: An application to QKD

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    Information Reconciliation is a mechanism that allows to weed out the discrepancies between two correlated variables. It is an essential component in every key agreement protocol where the key has to be transmitted through a noisy channel. The typical case is in the satellite scenario described by Maurer in the early 90's. Recently the need has arisen in relation with Quantum Key Distribution (QKD) protocols, where it is very important not to reveal unnecessary information in order to maximize the shared key length. In this paper we present an information reconciliation protocol based on a rate compatible construction of Low Density Parity Check codes. Our protocol improves the efficiency of the reconciliation for the whole range of error rates in the discrete variable QKD context. Its adaptability together with its low interactivity makes it specially well suited for QKD reconciliation

    Global survey of development banks

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    Historically, development banks have been an important instrument of governments to promote economic growth by providing credit and a wide range of advisory and capacity building programs to households, small and medium enterprises, and even large private corporations, whose financial needs are not sufficiently served by private commercial banks or local capital markets. During the current financial crisis, most development banks in Latin America, followed by Asia, Africa, and Europe, have assumed a countercyclical role by scaling up their lending operations exactly when private banks experienced temporary difficulties in granting credit to the private sector. Despite the importance of development banks during crisis and non-crisis periods, little is known about them. This survey examines how development banks operate, what their policy mandates are, what financial services they offer, which type of clients they target, how they are regulated and supervised, what business models they have adopted, what governance framework they have, and what challenges they face. It also examines the countercyclical role played by development banks during the recent financial crisis. This survey is based on new data that have been collected from 90 national development banks in 61 countries.Banks&Banking Reform,Access to Finance,Debt Markets,Bankruptcy and Resolution of Financial Distress,Emerging Markets
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