12,534 research outputs found

    Towards a compact representation of temporal rasters

    Get PDF
    Big research efforts have been devoted to efficiently manage spatio-temporal data. However, most works focused on vectorial data, and much less, on raster data. This work presents a new representation for raster data that evolve along time named Temporal k^2 raster. It faces the two main issues that arise when dealing with spatio-temporal data: the space consumption and the query response times. It extends a compact data structure for raster data in order to manage time and thus, it is possible to query it directly in compressed form, instead of the classical approach that requires a complete decompression before any manipulation. In addition, in the same compressed space, the new data structure includes two indexes: a spatial index and an index on the values of the cells, thus becoming a self-index for raster data.Comment: This research has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie Actions H2020-MSCA-RISE-2015 BIRDS GA No. 690941. Published in SPIRE 201

    Does Membership on the UN Security Council Influence IMF Conditionality?

    Full text link
    We investigate whether elected members of the United Nations Security Council receive favorable treatment from the International Monetary Fund (IMF), analyzing panel data on the level of conditionality attached to (a maximum of) 314 IMF arrangements with 101 countries over the period of 1992 to 2008. We find a negative relationship: Security Council members receive about 30 percent fewer conditions attached to the loans that they receive from the IMF. We conclude that conditionality is softer for these countries because the major shareholders of the IMF desire influence over the Security Council

    Financial Liberalization, Growth, Productivity and Capital Accumulation: The Case of European Integration

    Full text link
    In the present contribution, we concentrate on the process of financial liberalization in a specific context of European economic and monetary integration. We implement de facto and de jure measures of financial liberalization and find that formal aspects of financial openness generate a strongly positive impact on economic growth and its sources, productivity growth and capital accumulation. Moreover, there is evidence of a positive contribution to the process stemming from the EU membership, while no substantial effect comes from the euro adoption. Finally, we investigate the effects from financial integration on country groups within the EU

    Determinants of Carry Trades in Central and Eastern Europe

    Full text link
    In this paper, I analyze determinants of carry trade returns in Central and Eastern Europe (CEE). I show that carry trades to CEE were lucrative due to interest rate spreads between the funding and investment currency from 2004 to 2006. They became unprofitable when liquidity risk and exchange rate volatility increased after 2007. The analysis suggests that the exchange rate regime of the CEE economy matters for carry trade returns. Overall, exchange rate stabilization, particularly via managed floats, seems to allow for the highest profit opportunities

    Directional gene flow and ecological separation in Yersinia enterocolitica

    Get PDF
    Yersinia enterocolitica is a common cause of food-borne gastroenteritis worldwide. Recent work defining the phylogeny of the genus Yersinia subdivided Y. enterocolitica into six distinct phylogroups. Here, we provide detailed analyses of the evolutionary processes leading to the emergence of these phylogroups. The dominant phylogroups isolated from human infections, PG3–5, show very little diversity at the sequence level, but do present marked patterns of gain and loss of functions, including those involved in pathogenicity and metabolism, including the acquisition of phylogroup-specific O-antigen loci. We tracked gene flow across the species in the core and accessory genome, and show that the non-pathogenic PG1 strains act as a reservoir for diversity, frequently acting as donors in recombination events. Analysis of the core and accessory genome also suggested that the different Y. enterocolitica phylogroups may be ecologically separated, in contrast to the long-held belief of common shared ecological niches across the Y. enterocolitica species

    Bilateral Exports from Euro Zone Countries to the US - Does Exchange Rate Variability Play a Role?

    Full text link
    The financial crisis and the debt crisis in Europe lead to pronounced swings of the $/€-exchange rate. The influence of this exchange rate uncertainty on exports is neither theoretically nor empirically unambiguous. Therefore, this investigation tries to find out what effect exchange rate volatility has got on exports from eleven euro zone countries to the US. Our results suggest that if exchange rate volatility exerts a significant influence on exports, it is typically negative. Furthermore, exports of SITC categories 6 and 7 seem to be affected negatively most often

    Exporting and Productivity: Evidence for Egypt and Morocco

    Full text link
    This paper investigates the link between exporting and importing activities and firm performance using a rich dataset on Egyptian and Moroccan firms. We test the export premium, self-selection and learning-by-exporting hypotheses using a number of firm characteristics. Our analysis also includes importing activities as a source of learning and considers their effects on productivity changes. A differences-in-differences matching estimator is used to address the endogeneity bias of target variables. The main results for Egyptian firms echo those reported for other countries using firm-level data, namely exporters are larger and more productive than non-exporters. In contrast, Moroccan exporters and non-exporters are strikingly similar. More specifically, no evidence is found of pre or post-entry differences in labour productivity for Moroccan firms

    Similarities and differences of pumping conventional and self-compacting concrete

    Get PDF
    In Practice, Self-Compacting Concrete (SCC) is Considered as a Simple Extension of Conventional Vibrated Concrete (CVC) When Pumping is Concerned. the Same Equipment, Materials, Pumping Procedures and Guidelines Used for CVC Are Applied When Pumping SCC. on the Other Hand, It Has Been Clearly Shown that the Rheological Properties and the Mix Design of SCC Are Different Than CVC. Can the Same Pumping Principles Employed for CVC Be Applied for SCC? This Paper Compares the Some Published Results of Pumping of CVC with Those for SCC. a First Striking Difference between Pumping of CVC and SCC is the Flow Behaviour in the Pipes. the Flow of CVC is a Plug, Surrounded by a Lubricating Layer, While during the Flow of SCC, Part of the Concrete Volume itself is Sheared Inside the Pipe. as a Result, the Importance of Viscosity Increases in Case of SCC. Due to the Low Yield Stress of SCC, the Behaviour in Bends is Different, But Quite Complex to Study. Due to the Lower Content of Aggregate and Better Stability of SCC, as It is Less Prone to Internal Water Migration, Blocking is Estimated to Occur at Lower Frequency in Case of SCC. © RILEM 2010

    E-QED: Electrical Bug Localization During Post-Silicon Validation Enabled by Quick Error Detection and Formal Methods

    Full text link
    During post-silicon validation, manufactured integrated circuits are extensively tested in actual system environments to detect design bugs. Bug localization involves identification of a bug trace (a sequence of inputs that activates and detects the bug) and a hardware design block where the bug is located. Existing bug localization practices during post-silicon validation are mostly manual and ad hoc, and, hence, extremely expensive and time consuming. This is particularly true for subtle electrical bugs caused by unexpected interactions between a design and its electrical state. We present E-QED, a new approach that automatically localizes electrical bugs during post-silicon validation. Our results on the OpenSPARC T2, an open-source 500-million-transistor multicore chip design, demonstrate the effectiveness and practicality of E-QED: starting with a failed post-silicon test, in a few hours (9 hours on average) we can automatically narrow the location of the bug to (the fan-in logic cone of) a handful of candidate flip-flops (18 flip-flops on average for a design with ~ 1 Million flip-flops) and also obtain the corresponding bug trace. The area impact of E-QED is ~2.5%. In contrast, deter-mining this same information might take weeks (or even months) of mostly manual work using traditional approaches
    • …
    corecore