LINPRO: linear inverse problem library for data contaminated by statistical noise

The library LINPRO which provides solution to the linear inverse problem for data contaminated by a statistical noise is presented. The library makes use of two methods: Maximum Entropy Method and Singular Value Decomposition. As an example it has been applied to perform an analytic continuation of the imaginary time propagator obtained within the Quantum Monte Carlo method.Comment: The associated computer program is available at: http://tja.if.pw.edu.pl/linpro

An iterative thresholding algorithm for linear inverse problems with a sparsity constraint

We consider linear inverse problems where the solution is assumed to have a sparse expansion on an arbitrary pre-assigned orthonormal basis. We prove that replacing the usual quadratic regularizing penalties by weighted l^p-penalties on the coefficients of such expansions, with 1 < or = p < or =2, still regularizes the problem. If p < 2, regularized solutions of such l^p-penalized problems will have sparser expansions, with respect to the basis under consideration. To compute the corresponding regularized solutions we propose an iterative algorithm that amounts to a Landweber iteration with thresholding (or nonlinear shrinkage) applied at each iteration step. We prove that this algorithm converges in norm. We also review some potential applications of this method.Comment: 30 pages, 3 figures; this is version 2 - changes with respect to v1: small correction in proof (but not statement of) lemma 3.15; description of Besov spaces in intro and app A clarified (and corrected); smaller pointsize (making 30 instead of 38 pages

Time Delay and Time Advance in Resonance Theory

We propose a theory of the resonance-antiresonance scattering process which differs considerably from the classical one (the Breit-Wigner theory), which is commonly used in the phenomenological analysis. Here both resonances and antiresonances are described in terms of poles of the scattering amplitude: the resonances by poles in the first quadrant while the antiresonances by poles in the fourth quadrant of the complex angular momentum plane. The latter poles are produced by non-local potentials, which derive from the Pauli exchange forces acting among the nucleons or the quarks composing the colliding particles.Comment: 30 pages, 7 figure

PRODUÇÃO CIENTÍFICA BRASILEIRA EM ADMINISTRAÇÃO NA DÉCADA DE 2000

Presentation at the forum: scientific production in Business Administration in the period 2000-2010 with reflections and ideas in the area. Presentation at the forum: scientific production in Business Administration in the period 2000-2010 with reflections and ideas in the area

Coprocesamiento de bio-oils : Caracterización y pretratamiento térmico

Se estudió la pirólisis de distintas biomasas (aserrín de pino, aserrín de algarrobo y cáscara de trigo) en medio inerte (N2). Los bio-oils se generaron en un reactor de lecho fijo a 550ºC y con una rampa de 15ºC/min. La producción más elevada de bio-oil se obtuvo para el aserrín de pino (39%). Los bio-oils obtenidos se analizaron por GC/MS luego de someterse a fraccionamiento con agua y éter. Las fracciones contenían principalmente aldehídos, cetonas y fenoles. Se estudió el efecto de un tratamiento térmico sobre la composición de los bio-oils, con el fin de evaluar los cambios que podrían ayudar a coprocesarlos en refinerías convencionales, dado su alto potencial de formación de coque. El tratamiento térmico se realizó utilizando una rampa de 12ºC/min y temperatura final 500ºC. Este tratamiento produjo una fuerte disminución en el CCR, del orden del 70% y un leve aumento en el contenido de agua.The pyrolisis of biomass from different sources (pine and algarrobo sawdusts, and wheat shell) was studied under nitrogen flow. The bio-oils were produced in a fixed-bed reactor at 550 ºC, with a heating ramp of 15 ºC/min. The highest bio-oil yield (39 %) was obtained with pine sawdust. The bio-oils were analyzed by GC/MS after fractioning with water and ether. The different fractions contained mainly aldehydes, cetones and phenols. The effect of a thermal treatment over the composition of the bio-oils was studied in order to assess the changes that could help to co-process them in existing, conventional refineries, due to their high coking potential. The thermal treatment was performed under a heating ramp of 12 ºC/min and final temperature of 500 ºC. This treatment induced a strong decrease in the CCR, of about 70 %, and a slight increase in the content of water.Asociación Argentina de Energías Renovables y Medio Ambiente (ASADES

Coprocesamiento de bio-oils : Caracterización y pretratamiento térmico

Se estudió la pirólisis de distintas biomasas (aserrín de pino, aserrín de algarrobo y cáscara de trigo) en medio inerte (N2). Los bio-oils se generaron en un reactor de lecho fijo a 550ºC y con una rampa de 15ºC/min. La producción más elevada de bio-oil se obtuvo para el aserrín de pino (39%). Los bio-oils obtenidos se analizaron por GC/MS luego de someterse a fraccionamiento con agua y éter. Las fracciones contenían principalmente aldehídos, cetonas y fenoles. Se estudió el efecto de un tratamiento térmico sobre la composición de los bio-oils, con el fin de evaluar los cambios que podrían ayudar a coprocesarlos en refinerías convencionales, dado su alto potencial de formación de coque. El tratamiento térmico se realizó utilizando una rampa de 12ºC/min y temperatura final 500ºC. Este tratamiento produjo una fuerte disminución en el CCR, del orden del 70% y un leve aumento en el contenido de agua.The pyrolisis of biomass from different sources (pine and algarrobo sawdusts, and wheat shell) was studied under nitrogen flow. The bio-oils were produced in a fixed-bed reactor at 550 ºC, with a heating ramp of 15 ºC/min. The highest bio-oil yield (39 %) was obtained with pine sawdust. The bio-oils were analyzed by GC/MS after fractioning with water and ether. The different fractions contained mainly aldehydes, cetones and phenols. The effect of a thermal treatment over the composition of the bio-oils was studied in order to assess the changes that could help to co-process them in existing, conventional refineries, due to their high coking potential. The thermal treatment was performed under a heating ramp of 12 ºC/min and final temperature of 500 ºC. This treatment induced a strong decrease in the CCR, of about 70 %, and a slight increase in the content of water.Asociación Argentina de Energías Renovables y Medio Ambiente (ASADES

Differential Emission Measures from the Regularized Inversion of Hinode and SDO data

We develop and apply an enhanced regularization algorithm, used in RHESSI X-ray spectral analysis, to constrain the ill-posed inverse problem that is determining the DEM from solar observations. We demonstrate this computationally fast technique applied to a range of DEM models simulating broadband imaging data from SDO/AIA and high resolution line spectra from Hinode/EIS, as well as actual active region observations with Hinode/EIS and XRT. As this regularization method naturally provides both vertical and horizontal (temperature resolution) error bars we are able to test the role of uncertainties in the data and response functions. The regularization method is able to successfully recover the DEM from simulated data of a variety of model DEMs (single Gaussian, multiple Gaussians and CHIANTI DEM models). It is able to do this, at best, to over four orders of magnitude in DEM space but typically over two orders of magnitude from peak emission. The combination of horizontal and vertical error bars and the regularized solution matrix allows us to easily determine the accuracy and robustness of the regularized DEM. We find that the typical range for the horizontal errors is $\Delta$log$T\approx 0.1 -0.5$ and this is dependent on the observed signal to noise, uncertainty in the response functions as well as the source model and temperature. With Hinode/EIS an uncertainty of 20% greatly broadens the regularized DEMs for both Gaussian and CHIANTI models although information about the underlying DEMs is still recoverable. When applied to real active region observations with Hinode/EIS and XRT the regularization method is able to recover a DEM similar to that found via a MCMC method but in considerably less computational time.Comment: 15 pages, 17 figures, accepted for publication in A&