218 research outputs found

    Spectral-phase interferometry for direct electric-field reconstruction applied to seeded extreme-ultraviolet free-electron lasers

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    We present a setup for complete characterization of femtosecond pulses generated by seeded free-electron lasers (FEL's) in the extreme-ultraviolet spectral region. Two delayed and spectrally shifted replicas are produced and used for spectral phase interferometry for direct electric field reconstruction (SPIDER). We show that it can be achieved by a simple arrangement of the seed laser. Temporal shape and phase obtained in FEL simulations are well retrieved by the SPIDER reconstruction, allowing to foresee the implementation of this diagnostic on existing and future sources. This will be a significant step towards an experimental investigation and control of FEL spectral phase

    Improved Factorization of N=prqsN=p^rq^s

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    Bones et al. showed at Crypto 99 that moduli of the form N=prqN=p^rq can be factored in polynomial time when rlogpr \geq \log p. Their algorithm is based on Coppersmith\u27s technique for finding small roots of polynomial equations. Recently, Coron et al. showed that N=prqsN=p^rq^s can also be factored in polynomial time, but under the stronger condition rlog3pr \geq \log^3 p. In this paper, we show that N=prqsN=p^rq^s can actually be factored in polynomial time when rlogpr \geq \log p, the same condition as for N=prqN=p^rq

    Inconsistencies among European Union Pharmaceutical Regulator Safety Communications: A Cross-Country Comparison

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    The European Medicines Agency (EMA) and national regulators share the responsibility to communicate to healthcare providers postmarketing safety events but little is known about the consistency of this process. We aimed to compare public availability of safety-related communications and drug withdrawals from the EMA and European Union member countries for novel medicines. We performed a cross-sectional analysis using public Dear Healthcare Professional Communications (DHPCs) for all novel medicines authorized between 2001 and 2010 by the EMA and available for use in France, Netherlands, Spain, and the United Kingdom. Between 2001 and 2010, the EMA approved 185 novel medicines. DHPCs could not be ascertained for the EMA. Among the 4 national regulators, as of April 30, 2013, at least one safety DHPC or withdrawal occurred for 53 (28.6%) medicines, totaling 90 DHPCs and 5 withdrawals. Among these 53 medicines, all 4 national agencies issued at least one communication for 17 (32.1%), three of the four for 25 (47.2%), two of the four for 6 (11.3%), and one of the four for 5 (9.4%). Five drugs were reported to be withdrawn, three by all four countries, one by three and one by two. Among the 95 DHPCs and withdrawals, 20 (21.1%) were issued by all 4 national regulators, 37 (38.9%) by 3 of the 4, 22 (23.2%) by 2 of the 4, and 16 (16.8%) by one. Consistency of making publicly available all identified safety DHPC or withdrawal across regulator pairs varied from 33% to 73% agreement. Safety communications were not made publicly available by the EMA. Among the 4 European member countries with national regulators that make DHPCs publicly available since at least 2001, there were substantial inconsistencies in safety communications for novel medicines. The impact of those inconsistencies in terms of public health remains to be determined

    Automatic classification of registered clinical trials towards the Global Burden of Diseases taxonomy of diseases and injuries

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    Includes details on the implementation of MetaMap and IntraMap, prioritization rules, the test set of clinical trials and the classification of the external test set according to the 171 GBD categories. Dataset S1: Expert-based enrichment database for the classification according to the 28 GBD categories. Manual classification of 503 UMLS concepts that could not be mapped to any of the 28 GBD categories. Dataset S2: Expert-based enrichment database for the classification according to the 171 GBD categories. Manual classification of 655 UMLS concepts that could not be mapped to any of the 171 GBD categories, among which 108 could be projected to candidate GBD categories. Table S1: Excluded residual GBD categories for the grouping of the GBD cause list in 171 GBD categories. A grouping of 193 GBD categories was defined during the GBD 2010 study to inform policy makers about the main health problems per country. From these 193 GBD categories, we excluded the 22 residual categories listed in the Table. We developed a classifier for the remaining 171 GBD categories. Among these residual categories, the unique excluded categories in the grouping of 28 GBD categories were “Other infectious diseases” and “Other endocrine, nutritional, blood, and immune disorders”. Table S2: Per-category evaluation of performance of the classifier for the 171 GBD categories plus the “No GBD” category. Number of trials per GBD category from the test set of 2,763 clinical trials. Sensitivities, specificities (in %) and likelihood ratios for each of the 171 GBD categories plus the “No GBD” category for the classifier using the Word Sense Disambiguation server, the expert-based enrichment database and the priority to the health condition field. Table S3: Performance of the 8 versions of the classifier for the 171 GBD categories. Exact-matching and weighted averaged sensitivities and specificities for 8 versions of the classifier for the 171 GBD categories. Exact-matching corresponds to the proportion (in %) of trials for which the automatic GBD classification is correct. Exact-matching was estimated over all trials (N = 2,763), trials concerning a unique GBD category (N = 2,092), trials concerning 2 or more GBD categories (N = 187), and trials not relevant for the GBD (N = 484). The weighted averaged sensitivity and specificity corresponds to the weighted average across GBD categories of the sensitivities and specificities for each GBD category plus the “No GBD” category (in %). The 8 versions correspond to the combinations of the use or not of the Word Sense Disambiguation server during the text annotation, the expert-based enrichment database, and the priority to the health condition field as a prioritization rule. Table S4: Per-category evaluation of the performance of the baseline for the 28 GBD categories plus the “No GBD” category. Number of trials per GBD category from the test set of 2,763 clinical trials. Sensitivities and specificities (in %) of the 28 GBD categories plus the “No GBD” category for the classification of clinical trial records towards GBD categories without using the UMLS knowledge source but based on the recognition in free text of the names of diseases defining in each GBD category only. For the baseline a clinical trial records was classified with a GBD category if at least one of the 291 disease names from the GBD cause list defining that GBD category appeared verbatim in the condition field, the public or scientific titles, separately, or in at least one of these three text fields. (DOCX 84 kb

    A Variant of Coppersmith\u27s Algorithm with Improved Complexity and Efficient Exhaustive Search

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    Coppersmith described at Eurocrypt 96 a polynomial-time algorithm for finding small roots of univariate modular equations, based on lattice reduction. In this paper we describe the first improvement of the asymptotic complexity of Coppersmith\u27s algorithm. Our method consists in taking advantage of Coppersmith\u27s matrix structure, in order to apply LLL algorithm on a matrix whose elements are smaller than those of Coppersmith\u27s original matrix. Using the L2L^2 algorithm, the asymptotic complexity of our method is O(log6+ϵN)O(\log^{6+\epsilon} N) for any ϵ>0\epsilon > 0, instead of O(log8+ϵN)O(\log^{8+\epsilon} N) previously. Furthermore, we devise a method that allows to speed up the exhaustive search which is usually performed to reach Coppersmith\u27s theoretical bound. Our approach takes advantage of the LLL performed to test one guess, to reduce complexity of the LLL performed for the next guess. Experimental results confirm that it leads to a considerable performance improvement

    Factoring N=prqsN=p^r q^s for Large rr and ss

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    International audienceBoneh et al. showed at Crypto 99 that moduli of the form N = p^r q can be factored in polynomial time when r ≃ log(p). Their algorithm is based on Coppersmith’s technique for finding small roots of polynomial equations. In this paper we show that N = p^r q^s can also be factored in polynomial time when r or s is at least (log p)^3; therefore we identify a new class of integers that can be efficiently factored.We also generalize our algorithm to moduli with k prime factors N = \prod_{i=1}^k p_i^{r_i} ; we show that a non-trivial factor of N can be extracted in polynomial-time if one of the exponents r_i is large enough

    Factoring N=p^r q^s for Large r and s

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    Boneh et al. showed at Crypto 99 that moduli of the form N=p^r q can be factored in polynomial time when r=log p. Their algorithm is based on Coppersmith\u27s technique for finding small roots of polynomial equations. In this paper we show that N=p^r q^s can also be factored in polynomial time when r or s is at least (log p)^3; therefore we identify a new class of integers that can be efficiently factored. We also generalize our algorithm to moduli N with k prime factors; we show that a non-trivial factor of N can be extracted in polynomial-time if one of the k exponents is large enough

    Improved Gadgets for the High-Order Masking of Dilithium

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    We present novel and improved high-order masking gadgets for Dilithium, a post-quantum signature scheme that has been standardized by the National Institute of Standards and Technologies (NIST). Our proposed gadgets include the ShiftMod gadget, which is used for efficient arithmetic shifts and serves as a component in other masking gadgets. Additionally, we propose a new algorithm for Boolean-to-arithmetic masking conversion of a μ\mu-bit integer xx modulo any integer qq, with a complexity that is independent of both μ\mu and qq. This algorithm is used in Dilithium to mask the generation of the random variable yy modulo qq. Moreover, we describe improved techniques for masking the Decompose function in Dilithium. Our new gadgets are proven to be secure in the tt-probing model. We demonstrate the effectiveness of our countermeasures by presenting a complete high-order masked implementation of Dilithium that utilizes the improved gadgets described above. We provide practical results obtained from a C implementation and compare the performance improvements provided by our new gadgets with those of previous work
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