Implementación software eficiente de la Transformada de Fourier escasa casi óptima para el caso con ruido

In this paper we present an optimized software implementation (sFFT-4.0) of the recently developed Nearly Optimal Sparse Fast Fourier Transform (sFFT) algorithm for the noisy case -- First, we developed a modified version of the Nearly Optimal sFFT algorithm for the noisy case, this modified algorithm solves the accuracy issues of the original version by modifying the flat window and the procedures; and second, we implemented the modified algorithm on a multicore platform composed of eight cores -- The experimental results on the cluster indicate that the developed implementation is faster than direct calculation using FFTW library under certain conditions of sparseness and signal size, and it improves the execution times of previous implementations like sFFT-2.0 -- To the best knowledge of the authors, the developed implementation is the first one of the Nearly Optimal sFFT algorithm for the noisy caseEn este artículo se presenta una implementación software optimizada (sFFT- 4.0) del algoritmo Transformada Rápida de Fourier Escasa (sFFT) Casi Óptimo para el caso con ruido -- En primer lugar, se desarrolló una versión modificada del algoritmo sFFT Casi Óptimo para el caso con ruido, esta modificación resuelve los problemas de exactitud de la versión original al modificar la ventana plana y los procedimientos; y en segundo lugar, se implementó el algoritmo modificado en una plataforma multinúcleo compuesta de ocho núcleos -- Los resultados experimentales en el agrupamiento de computadores muestran que la implementación desarrollada es más rápida que el cálculo directo usando la biblioteca FFTW bajo ciertas condiciones de escases y tamaño de señal, y mejora los tiempos de ejecución de implementaciones previas como sFFT-2.0 -- Al mejor conocimiento de los autores, la implementación desarrollada es la primera del algoritmo sFFT Casi Óptimo para el caso con ruid

Diseño de criptoprocesadores de curva elíptica sobre gf(2^163) usando bases normales gaussianas

This paper presents the efficient hardware implementation of cryptoprocessors that carry out the scalar multiplication kP over finite field GF(2163) using two digit-level multipliers. The finite field arithmetic operations were implemented using Gaussian normal basis (GNB) representation, and the scalar multiplication kP was implemented using Lopez-Dahab algorithm, 2-NAF halve-and-add algorithm and w-tNAF method for Koblitz curves. The processors were designed using VHDL description, synthesized on the Stratix-IV FPGA using Quartus II 12.0 and verified using SignalTAP II and Matlab. The simulation results show that the cryptoprocessors present a very good performance to carry out the scalar multiplication kP. In this case, the computation times of the multiplication kP using Lopez-Dahab, 2-NAF halve-and-add and 16-tNAF for Koblitz curves were 13.37 µs, 16.90 µs and 5.05 µs, respectively.En este trabajo se presenta la implementación eficiente en hardware de criptoprocesadores que permiten llevar a cabo la multiplicación escalar kP sobre el campo finito GF(2163) usando dos multiplicadores a nivel de digito. Las operaciones aritméticas de campo finito fueron implementadas usando la representación de bases normales Gaussianas (GNB), y la multiplicación escalar kP fue implementada usando el algoritmo de López-Dahab, el algoritmo de bisección de punto 2-NAF y el método w-tNAF para curvas de Koblitz. Los criptoprocesadores fueron diseñados usando descripción VHDL, sintetizados en el FPGA Stratix-IV usando Quartus II 12.0 y verificados usando SignalTAP II y Matlab. Los resultados de simulación muestran que los criptoprocesadores presentan un muy buen desempeño para llevar a cabo la multiplicación escalar kP. En este caso, los tiempos de computo de la multiplicación kP usando Lopez-Dahab, bisección de punto 2-NAF y 16-tNAF para curvas de Koblitz fueron 13.37 µs, 16.90 µs and 5.05 µs, respectivamente

Implementación hardware del algoritmo Keccak para Hash-3 y comparación con Blake, Grøstl, JH y Skein

Cryptographic hash functions convert a variable-length message into a “message digest” and are used for digital signature applications, message authentication codes, and other information security applications. Recent attacks carried out on SHA-1 have been published; therefore, the National Institute for Standards and Technology (NIST) issued an open call to select the SHA-3 for the new standard. As a result, among the five finalists: Blake, Gröstl, JH, Keccak and Skein, Keccak was selected. In this paper, the five finalist algorithms were implemented in hardware using pipelined architectures for the different roundsof the iterative process. The hardware architectures were simulated and synthesized using ModelSim-Altera and Quartus II v.11.2, respectively. The synthesis results show that alternatives exist to be used as IP cores for cryptographic applications embedded in a SoC.Las funciones criptográficas Hash convierten un mensaje de longitud variable en un “resumen del mensaje”, y son usadas para aplicaciones de firma digital, códigos de autenticación de mensajes y otras aplicaciones para seguridad informática. Recientes ataques realizados al estándar SHA-1 han sido publicados, por lo tanto, el National Institute for Standards and Technology (NIST) realizó una convocatoria pública para seleccionar el algoritmo SHA-3 para el nuevo estándar. Como resultado, entre los cinco algoritmos finalistas: Blake, Grøstl, JH, Keccak y Skein, el seleccionado fue Keccak. En este trabajo se implementaron en hardware los cinco algoritmos finalistas usando arquitecturas pipeline para las diferentes rondas del proceso iterativo. Las arquitecturas hardware fueron simuladas y sintetizadas usando Modelsim-Altera y Quartus II v.11.2, respectivamente. Los resultados de síntesis muestran que existen alternativas para ser usadas como IP cores en aplicaciones criptográficas embebidas en un SoC

Role of B Cell Profile for Predicting Secondary Autoimmunity in Patients Treated With Alemtuzumab

UDHEBRONTo explore if baseline blood lymphocyte profile could identify relapsing remitting multiple sclerosis (RRMS) patients at higher risk of developing secondary autoimmune adverse events (AIAEs) after alemtuzumab treatment. Multicenter prospective study including 57 RRMS patients treated with alemtuzumab followed for 3.25 [3.5-4.21] years, (median [interquartile range]). Blood samples were collected at baseline, and leukocyte subsets determined by flow cytometry. We had additional samples one year after the first cycle of alemtuzumab treatment in 39 cases. Twenty-two patients (38.6%) developed AIAEs during follow-up. They had higher B-cell percentages at baseline (p=0.0014), being differences mainly due to plasmablasts/plasma cells (PB/PC, p=0.0011). Those with no AIAEs had higher percentages of CD4+ T cells (p=0.013), mainly due to terminally differentiated (TD) (p=0.034) and effector memory (EM) (p=0.031) phenotypes. AIAEs- patients also showed higher values of TNF-alpha-producing CD8+ T cells (p=0.029). The percentage of PB/PC was the best variable to differentiate both groups of patients. Baseline values >0.10% closely associated with higher AIAE risk (Odds ratio [OR]: 5.91, 95% CI: 1.83-19.10, p=0.004). When excluding the 12 patients with natalizumab, which decreases blood PB/PC percentages, being the last treatment before alemtuzumab, baseline PB/PC >0.1% even predicted more accurately the risk of AIAEs (OR: 11.67, 95% CI: 2.62-51.89, p=0.0007). The AIAEs+ group continued having high percentages of PB/PC after a year of alemtuzumab treatment (p=0.0058). A PB/PC percentage <0.1% at baseline identifies MS patients at low risk of secondary autoimmunity during alemtuzumab treatment.

Constraints on the χ_(c1) versus χ_(c2) polarizations in proton-proton collisions at √s = 8 TeV

The polarizations of promptly produced χ_(c1) and χ_(c2) mesons are studied using data collected by the CMS experiment at the LHC, in proton-proton collisions at √s=8  TeV. The χ_c states are reconstructed via their radiative decays χ_c → J/ψγ, with the photons being measured through conversions to e⁺e⁻, which allows the two states to be well resolved. The polarizations are measured in the helicity frame, through the analysis of the χ_(c2) to χ_(c1) yield ratio as a function of the polar or azimuthal angle of the positive muon emitted in the J/ψ → μ⁺μ⁻ decay, in three bins of J/ψ transverse momentum. While no differences are seen between the two states in terms of azimuthal decay angle distributions, they are observed to have significantly different polar anisotropies. The measurement favors a scenario where at least one of the two states is strongly polarized along the helicity quantization axis, in agreement with nonrelativistic quantum chromodynamics predictions. This is the first measurement of significantly polarized quarkonia produced at high transverse momentum