Search results for "Parametric"
showing 10 items of 980 documents
Methodological aspects for the use of surfaces parametric modelers in architectural design. A study case
2017
Il presente studio affronta le implicazioni metodologiche determinate nello svolgimento di un iter progettuale tramite utilizzo di un modellatore parametrico algoritmico. L’obiettivo è quello di dimostrare come la parametrizzazione degli elementi morfologici debba generare un rapporto biunivoco con le logiche progettuali, ma senza dettarne le direttive o stravolgerle. Oggetto dell’intervento progettuale è un centro polifunzionale a vocazione turistica di servizio all’area del Parco Archeologico di Agrigento, che instauri con la Valle dei Templi un rapporto contestuale di dialogo morfologico e visivo. The present study addresses the methodological implications determined in the carrying out …
Elaborazione parametrica di segnali ottici
2012
Questa tesi presenta una panoramica dell‘attività di ricerca da me svolta in questo triennio di dottorato, avente come oggetto la progettazione, la fabbricazione e la caratterizzazione di dispositivi non lineari in ottica integrata per l‘elaborazione parametrica dei segnali. Gli aspetti funzionali di questi dispositivi, le proprietà non lineari del secondo ordine dei materiali di cui sono composti così come i risultati dei processi di fabbricazione necessitano di un‘analisi teorica approfondita che ne consenta l‘effettiva applicazione alle comunicazioni ottiche. Il primo capitolo è un‘attenta disamina del metodo del Quasi-Phase-Matching mediante il quale si ha l‘implementazione del fenomeno…
Backward second-harmonic generation of near infrared picosecond pulses
2014
We report on backward second-harmonic generation using picosecond laser pulses in congruent lithium niobate with 3.2 µm periodic poling. By tuning both the pump wavelength and the sample temperature, we observed three resonant peaks in the range 1530-1730 nm, corresponding to 16th, 17th and 18th quasi-phase-matching orders, respectively. A maximum conversion efficiency of 0.475% was achieved at the 16th order with a 10 kW peak pump power. The latter is the highest conversion reported in bulk to date, for the backward configuration, with an improvement greater than 50% with respect to those previously achieved with nanosecond pulses for the same order of resonance.
Real-Time Visual Grasp Synthesis Using Genetic Algorithms and Neural Networks
2007
This paper addresses the problem of automatic grasp synthesis of unknown planar objects. In other words, we must compute points on the object’s boundary to be reached by the robotic fingers such that the resulting grasp, among infinite possibilities, optimizes some given criteria. Objects to be grasped are represented as superellipses, a family of deformable 2D parametric functions. They can model a large variety of shapes occurring often in practice by changing a small number of parameters. The space of possible grasp configurations is analyzed using genetic algorithms. Several quality criteria from existing literature together with kinematical and mechanical considerations are considered.…
Parametric Natura Morta
2018
Parametric equations can also be used to draw fruits, shells, and a cornucopia of a mathematical still life. Simple mathematics allows the creation of a variety of shapes and visual artworks, and it can also constitute a pedagogical tool for students.
Growth Volatility and the Structure of the Economy
2011
The aim of the chapter is twofold: (i) to propose a methodology to compute the growth rate volatility of an economy and (ii) to investigate the relationship between growth volatility and economic development through the lenses of the structural characteristics of an economy. We study a large cross-section of countries in the period 1970–2009, controlling for the stability of the estimates in two subperiods: 1970:1989 (Period I) and 1990:2009 (Period II). Our main findings are (i) the degree of trade openness has a destabilizing effect, while the degree of financial openness has not a significant effect; (ii) the size of the public sector displays a U-shaped relationship with growth volatili…
A comparison of local parametric C0 Bézier interpolants for triangular meshes
2011
Parametric curved shape surface schemes interpolating vertices and normals of a given triangular mesh with arbitrary topology are widely used in computer graphics for gaming and real-time rendering due to their ability to effectively represent any surface of arbitrary genus. In this context, continuous curved shape surface schemes using only the information related to the triangle corresponding to the patch under construction, emerged as attractive solutions responding to the requirements of resource-limited hardware environments. In this paper we provide a unifying comparison of the local parametric C^0 curved shape schemes we are aware of, based on a reformulation of their original constr…
Nonparametric statistics for DOA estimation in the presence of multipath
2002
This paper is concerned with array signal processing in nonGaussian noise and in the presence of multipath. Robust and fully nonparametric high resolution algorithms for direction of arrival (DOA) estimation are presented. The algorithms are based on multivariate spatial sign and rank concepts. Spatial smoothing of the multivariate rank and sign based covariance matrices is employed as a preprocessing step in order to deal with coherent sources. The performance of the algorithms is studied using simulations. The results show that almost optimal performance is obtained in wide variety of different noise conditions.
Support Vector Machines Framework for Linear Signal Processing
2005
This paper presents a support vector machines (SVM) framework to deal with linear signal processing (LSP) problems. The approach relies on three basic steps for model building: (1) identifying the suitable base of the Hilbert signal space in the model, (2) using a robust cost function, and (3) minimizing a constrained, regularized functional by means of the method of Lagrange multipliers. Recently, autoregressive moving average (ARMA) system identification and non-parametric spectral analysis have been formulated under this framework. The generalized, yet simple, formulation of SVM LSP problems is particularized here for three different issues: parametric spectral estimation, stability of I…
Robust subspace DOA estimation for wireless communications
2002
This paper is concerned with array signal processing in non-Gaussian noise typical in urban and indoor radio channels. Robust and fully nonparametric high resolution algorithms for direction of arrival (DOA) estimation are presented. The algorithms are based on multivariate spatial sign and rank concepts. The performance of the algorithms is studied using simulations. The results show that almost optimal performance is obtained in wide variety of noise conditions.