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Search Results: 1 - 10 of 3612 matches for " Fabrizio Palma "
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Floquet Eigenvectors Theory of Pulsed Bias Phase and Quadrature Harmonic Oscillators  [PDF]
Fabrizio Palma, Stefano Perticaroli
Circuits and Systems (CS) , 2012, DOI: 10.4236/cs.2012.31010
Abstract: The paper presents an analytical derivation of Floquet eigenvalues and eigenvectors for a class of harmonic phase and quadrature oscillators. The derivation refers in particular to systems modeled by two parallel RLC resonators with pulsed energy restoring. Pulsed energy restoring is obtained through parallel current generators with an impulsive characteristic triggered by the resonators voltages. In performing calculation the initial hypothesis of the existence of stable oscillation is only made, then it is verified when both oscillation amplitude and eigenvalues/eigenvectors are deduced from symmetry conditions on oscillator space state. A detailed determination of the first eigenvector is obtained. Remaining eigenvectors are hence calculated with realistic approximations. Since Floquet eigenvectors are acknowledged to give the correct decomposition of noise perturbations superimposed to the oscillator space state along its limit cycle, an analytical and compact model of their behavior highlights the unique phase noise properties of this class of oscillators.
Phase and Quadrature Pulsed Bias LC-CMOS VCO  [PDF]
Stefano Perticaroli, Fabrizio Palma, Adriano Carbone
Circuits and Systems (CS) , 2011, DOI: 10.4236/cs.2011.21004
Abstract: Pulsed bias is an attempt to improve the performance of oscillators in integrated circuits as a result of architectural innovation. Given the relatively low value of resonator quality factor achievable on-chip, for a specified bias voltage level, pulsed bias may result in a lower power consumption and in an improvement of the spectral purity of the oscillation. The main drawback of this approach is the need to introduce a certain time delay in order to properly position pulses with respect to oscillation waveform. Delay accumulation requires further energy dissipation and introduce additional jitter. In this paper we present a new architecture capable to avoid unnecessary delay, based on the idea to apply the pulsed bias approach to a quadrature oscillator. A ?rst circuit-level implementation of this concept is presented with simulation results.
Derivation of Floquet Eigenvectors Displacement for Optimal Design of LC Tank Pulsed Bias Oscillators  [PDF]
Stefano Perticaroli, Nikend Luli, Fabrizio Palma
Circuits and Systems (CS) , 2011, DOI: 10.4236/cs.2011.24043
Abstract: The paper presents an approximated and compact derivation of the mutual displacement of Floquet eigenvectors in a class of LC tank oscillators with time varying bias. In particular it refers to parallel tank oscillators of which the energy restoring can be modeled through a train of current pulses. Since Floquet eigenvectors are acknowledged to give a correct decomposition of noise perturbations along the stable orbit in oscillator's space state, an analytical and compact model of their displacement can provide useful criteria for designers. The goal is to show, in a simplified case, the achievement of oscillators design oriented by eigenvectors. To this aim, minimization conditions of the effect of stationary and time varying noise as well as the contribution of jitter noise introduced by driving electronics are deduced from analytical expression of eigenvectors displacement.
CMOS Phase and Quadrature Pulsed Differential Oscillators Coupled through Microstrip Delay-Lines  [PDF]
Francesco Stilgenbauer, Stefano Perticaroli, Fabrizio Palma
Circuits and Systems (CS) , 2014, DOI: 10.4236/cs.2014.58020
Abstract:

An innovative solution to design phase and quadrature pulsed coupled oscillators systems through electromagnetic waveguides is described in this paper. Each oscillator is constituted by an LC differential resonator refilled through a couple of current pulse generator circuits. The phase and quadrature coupling between the two differential oscillators is achieved using delayed replicas of generated fundamentals from a resonator as driving signal of pulse generator injecting in the other resonator. The delayed replicas are obtained by microstrip-based delay-lines. A 2.4 - 2.5 GHz VCO has been implemented in a 150 nm RF CMOS process. Simulations showed at 1 MHz offset a phase noise of -139.9 dBc/Hz and a FOM of -189.1 dB.

Correspondence Analysis on a Space-Time Data Set for Multiple Environmental Variables  [PDF]
Palma Monica
International Journal of Geosciences (IJG) , 2015, DOI: 10.4236/ijg.2015.610090
Abstract: Applications of the multivariate technique called correspondence analysis for environmental studies are relatively new and are limited to spatial multivariate data set. In this paper, a procedure of applying correspondence analysis to a large space-time data set for multiple environmental variables is shown. In particular, nitrogen dioxide and carbon monoxide hourly concentrations measured during January 1999 at several monitored stations in a district of Northern Italy are analyzed. The procedure consists in transforming the continuous variables into categorical ones by the means of appropriate indicator variables, generating special contingency tables and applying correspondence analysis. The use of this classical multivariate technique allows the identification of important relationships among pollution levels and monitoring stations and/or relationships among pollution levels and observation times.
Accurate Tools for Analyzing the Behavior of Impulse Noise Reduction Filters in Color Images  [PDF]
Fabrizio Russo
Journal of Signal and Information Processing (JSIP) , 2013, DOI: 10.4236/jsip.2013.41005
Abstract:

Effective cancellation of noise and preservation of color/structural information are features of paramount importance for any filter devoted to impulse noise removal in color images. In this paper novel full-reference tools for analyzing the behavior of this family of filters are presented. The proposed approach is based on the classification of color errors into two main classes that separately take into account the inaccuracy in removing noise pulses and the filtering distortion. The distortion errors are then classified into two subclasses for a deeper analysis of the filtering behavior. Computer simulations show that the proposed method gives more accurate results than using other measures of filtering performance in the literature. Furthermore, the method can easily yield the spatial location of the different filtering features in the image.

Relativistic Derivations of de Broglie and Planck-Einstein Equations  [PDF]
Fabrizio Logiurato
Journal of Modern Physics (JMP) , 2014, DOI: 10.4236/jmp.2014.51001
Abstract:

Special Relativity sets tight constraints on the form of the possible relations between the four-momentum of a particle and the wave four-vector. In fact, we demonstrate that there is just one way, according to Special Relativity, to relate the energy and the momentum of a corpuscle with the characteristics of a plane wave, frequency and wave vector, if the momentum has to flow in the same direction of the wave propagation: the laws must be of direct proportionality like de Broglie \"\" and Planck-Einstein \"\" equations.

Hábitos alimentarios en adolescentes de séptimo grado del municipio "10 de Octubre"
Valdés Gómez,Wendy; Leyva álvarez de la Campa,Graciel; Espinosa Reyes,Tania Mayvel; Palma Tobar,Carlos Fabrizio;
Revista Cubana de Endocrinolog?-a , 2012,
Abstract: introduction: the nutrition plays a critical role in the adolescent health and the consumption of a inappropriate diet may to influence in an unfavorable way on the somatic growth and the sexual maturation being a crucial stage of development where frequently prevail the nutritional disorders. methods: a cross-sectional and descriptive study was conducted to identify and to describe the tastes, preferences and frequency of food consumption of adolescent of 7th degree studying in the "josé maría heredia" secondary school in the 2009-2010 course. sample included 192 adolescents and with the parents consent underwent to alimentary survey on tastes, preferences and weekly frequency of food consumption. results: the more preferred foods were the butter, mayonnaise and cream-cheese, sweets, preserves and soft drinks, mainly consumed daily; unlike the fruits and vegetables. the 14.1 % of adolescents preferred the alcohol and the 15.6 % consumed them at least once a week. conclusions: there are deficiencies in the alimentary education as well as inappropriate alimentary habits in the study adolescents.
Estado nutricional en adolescentes, exceso de peso corporal y factores asociados
Valdés Gómez,Wendy; Leyva álvarez de la Campa,Graciel; Espinosa Reyes,Tania Mayvel; Palma Tobar,Carlos Fabrizio;
Revista Cubana de Endocrinolog?-a , 2011,
Abstract: introduction: the adolescence is a decisive stage with a high level of prevalence of nutritional disorders that latter remains during the adulthood and are associated with short- and long term complications. objectives: to identify the association between excess of body weight and the interesting family pathological backgrounds and some perinatal risks, the presence of high blood pressure and its relation to the family history of high blood pressure and the increase of abdominal adiposity and finally, to identify the presence of acanthosis nigricans and its relation with the similar factors. methods: a cross-sectional and descriptive study was conducted to characterize the nutritional status of the adolescents of the seventh grade from the "josé maría heredia" secondary school during 2009-2020. group included 192 adolescents who with a previous consent of parents underwent anthropometric measurements (weight, height, waist circumference and estimation of the body mass index) and also the blood pressure and search of clinical signs of insulin resistance. a survey to parents on the family pathological backgrounds and on some data of their children was applied. results: there was that the 20,31 % of adolescents had excess weight or obesity, which was related in a significant way to the presence of a high blood pressure and clinical signs of insulin resistance. the high blood pressure was present in the 9,9 % of adolescents without any relation to hereditary factors. conclusions: obesity and body excess weight are a health problem in study adolescent population, which is associated with the presence of a high blood pressure and insulin resistance; there was not relation in its behavior to non-modifiable factors (family and personal pathological backgrounds).
Hábitos alimentarios en adolescentes de séptimo grado del municipio "10 de Octubre" Alimentary habits in adolescents of 7th degree from "10 de Octubre" municipality
Wendy Valdés Gómez,Graciel Leyva álvarez de la Campa,Tania Mayvel Espinosa Reyes,Carlos Fabrizio Palma Tobar
Revista Cubana de Endocrinología , 2012,
Abstract: Introducción: la nutrición juega un papel crítico en la salud del adolescente, y el consumo de una dieta inadecuada puede influir desfavorablemente sobre el crecimiento somático y la maduración sexual, por lo que constituye una etapa crucial del desarrollo, en la que prevalecen con alta frecuencia trastornos nutricionales. Métodos: se desarrolló un estudio descriptivo transversal, con el objetivo principal de identificar y describir los gustos, preferencias y frecuencia de consumo de alimentos de los adolescentes de séptimo grado que asisten a la Secundaria Básica "José María Heredia", en el curso 2009-2010. La población estuvo constituida por 192 adolescentes, a los cuales con previo consentimiento de los padres, se les aplicó una encuesta alimentaria de gustos, preferencias y frecuencia semanal de consumo de alimentos. Resultados: los grupos de alimentos que más gustaron fueron mantequilla, mayonesa y queso crema, dulces, confituras y refrescos, mayormente consumidos a diario, a diferencia de las frutas y vegetales. El 14,1 % de los adolescentes gustaban de bebidas alcohólicas, y el 15,6 % las consumía al menos una vez a la semana. Conclusiones: existen deficiencias en la educación alimentaria e inadecuados hábitos alimentarios en los adolescentes estudiados. Introduction: the nutrition plays a critical role in the adolescent health and the consumption of a inappropriate diet may to influence in an unfavorable way on the somatic growth and the sexual maturation being a crucial stage of development where frequently prevail the nutritional disorders. Methods: a cross-sectional and descriptive study was conducted to identify and to describe the tastes, preferences and frequency of food consumption of adolescent of 7th degree studying in the "José María Heredia" Secondary School in the 2009-2010 course. Sample included 192 adolescents and with the parents consent underwent to alimentary survey on tastes, preferences and weekly frequency of food consumption. Results: the more preferred foods were the butter, mayonnaise and cream-cheese, sweets, preserves and soft drinks, mainly consumed daily; unlike the fruits and vegetables. The 14.1 % of adolescents preferred the alcohol and the 15.6 % consumed them at least once a week. Conclusions: there are deficiencies in the alimentary education as well as inappropriate alimentary habits in the study adolescents.
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