Search results for "Geometric"

Influence of some relevant process parameters on the dimensional accuracy in incremental forming: a numerical and experimental investigation

2004

Abstract As known, incremental forming is a flexible and innovative sheet metal forming process which allows complex shape shells forming without the need for any die. For these reasons, incremental forming is nowadays suggested for rapid prototyping and customised products. The present paper is focused on material formability in incremental forming and, in particular, on the evaluation and compensation of elastic springback. The latter significantly modifies the imposed shape. For this purpose, a deeper assessment of the process was developed following three different approaches. First of all, a wide experimental investigation on the influence of some relevant process parameters was develo…

A Neural Architecture for Segmentation and Modelling of Range Data

2003

A novel, two stage, neural architecture for the segmentation of range data and their modeling with undeformed superquadrics is presented. The system is composed by two distinct neural stages: a SOM is used to perform data segmentation, and, for each segment, a multi-layer feed-forward network performs model estimation. The topology preserving nature of the SOM algorithm makes this architecture suited to cluster data with respect to sudden curvature variations. The second stage is designed to model and compute the inside-outside function of an undeformed superquadric in whatever attitude, starting form the (x, y, z) data triples. The network has been trained using backpropagation, and the we…

The 2017 May 20 stellar occultation by the elongated centaur (95626) 2002 GZ32

2021

Full list of authors: Santos-Sanz, P.; Ortiz, J. L.; Sicardy, B.; Benedetti-Rossi, G.; Morales, N.; Fernández-Valenzuela, E.; Duffard, R.; Iglesias-Marzoa, R.; Lamadrid, J. L.; Maícas, N.; Pérez, L.; Gazeas, K.; Guirado, J. C.; Peris, V.; Ballesteros, F. J.; Organero, F.; Ana-Hernández, L.; Fonseca, F.; Alvarez-Candal, A.; Jiménez-Teja, Y. Vara-Lubiano, M.; Braga-Ribas, F.; Camargo, J. I. B.; Desmars, J.; Assafin, M.; Vieira-Martins, R.; Alikakos, J.; Boutet, M.; Bretton, M.; Carbognani, A.; Charmandaris, V.; Ciabattari, F.; Delincak, P.; Fuambuena Leiva, A.; González, H.; Haymes, T.; Hellmich, S.; Horbowicz, J.; Jennings, M.; Kattentidt, B.; Kiss, Cs; Komžík, R.; Lecacheux, J.; Marciniak, …

Dal rilievo alla ricostruzione del progetto: la torre Pisana nel Palazzo Reale di Palermo

2017

The paper focuses the survey and representation of the Pisana Tower in the Royal Palace of Palermo. The tower, which has recently been inserted in the UNESCO World Heritage List, was built in the XII century under the patronage of Norman kings. Along the centuries, the tower has undergone several transformations, to fit ever-changing uses. The coexistence of such heterogeneous elements, combined with the fragmentation of the passages connecting the levels of the tower, conceal the original unity and the typology of this historical building. Researches focusing the study of monuments deeply transformed along their history, even when based on the cooperation of multidisciplinary scholarships,…

A geometric street scattering channel model for car-to-car communication systems

2011

This paper presents a geometric street scattering channel model for car-to-car (C2C) communication systems under line-of-sight (LOS) and non-LOS (NLOS) propagation conditions. Starting from the geometric model, we develop a stochastic reference channel model, where the scatterers are uniformly distributed in rectangles in the form of stripes parallel to both sides of the street. We derive analytical expressions for the probability density functions (PDFs) of the angle-of-departure (AOD) and the angle-of-arrival (AOA). We also investigate the Doppler power spectral density (PSD) and the autocorrelation function (ACF) of the proposed model, assuming that the mobile transmitter (MT) and the mo…

Ecomorphological variation within and among the two marine species of genus Salaria: Salaria basilisca and Salaria pavo (Perciformes: Blenniidae)

2022

In order to highlight the variation of the form due to the presence of different ecological factors, we investigated in this paper the morphological variation between and within the two marine species Salaria basilisca and S. pavo. This study was based on two approaches, the Truss network and the geometric morphometric and involved specimens of both species divided into marine and lagoon samples. The two approaches yielded complementary results showing clear morphological discrimination of the two species Thus, S. basilisca is distinguished by a higher depth and length as well as a higher head with a compressed snout compared to S. pavo which has a shortened body, a lower head and a slightl…

Berry Phase and Parametric Harmonic Oscillator

2001

Our concern in this section is once more with the time-dependent harmonic oscillator with Lagrangian $$\displaystyle{ L = \frac{1} {2}\dot{x}^{2} -\frac{1} {2}\omega ^{2}(t)x^{2}\;. }$$ To present a coherent picture of the whole problem, let us briefly review some of the results of Chap. 21. There we found the propagation function

A Geometric Algebra Based Distributional Model to Encode Sentences Semantics

2013

Word space models are used to encode the semantics of natural language elements by means of high dimensional vectors [23]. Latent Semantic Analysis (LSA) methodology [15] is well known and widely used for its generalization properties. Despite of its good performance in several applications, the model induced by LSA ignores dynamic changes in sentences meaning that depend on the order of the words, because it is based on a bag of words analysis. In this chapter we present a technique that exploits LSA-based semantic spaces and geometric algebra in order to obtain a sub-symbolic encoding of sentences taking into account the words sequence in the sentence. © 2014 Springer-Verlag Berlin Heidel…

Shape change during the growth of sharpsnout seabream reared under different conditions in a fish farm of the southern Tyrrhenian Sea

2003

Morphometric diversity of the mussel Brachidontes pharaonis in different coastal environments

2010

In the debate on how and why biodiversity evolves spatially and temporally and in an attempt to assess the further effects of anthropogenic activities, the ability of marine invertebrate to express a large spectrum of phenotypical plasticity can have a central role. The ability of a single genotype to produce more than one alternative form of morphology and/or physiological state should be larger in species living in highly changing waters like shallow habitats. Invertebrates, there, usually experience ample changes of temperature and food availability on annual, seasonal, diurnal and hourly bases which are the two main drivers leading the life histories of these organisms. In such circumst…