Search results for "Rotation"

Medical image registration: Interpolations, similarities and optimizations strategies

2010

This paper presents a study conducted for evaluating different interpolation schemes, similarity metrics and optimization algorithms for the purpose of volumetric medical image registration. Each technique has been implemented to be plugged in a modular system. Rotation, translation and scale error has been measured to obtain a performance evaluation for all of the combinations of the considered techniques. Several experimental tests were conducted for validation both on synthetic and real datasets providing an exhaustive overview of the various strategies used.

The effects of mental rotation on computational thinking

2019

Abstract Although several investigations of spatial reasoning and mental rotation skills have been conducted in research areas linked to STEM education, to the best of our knowledge, few of these studies have examined the relationship between spatial reasoning and computational thinking. Given this gap in the literature, the present study investigates the role and action of spatial reasoning, and specifically the effects of mental rotation on computational thinking within an embodied and enacted perspective. To achieve this, we carried out a study involving 92 students in five primary-school classes (1st grade - 5th grade). The findings reveal a positive correlation between computational th…

Fast Volumetric Reconstruction of Human Body through Superquadrics

2013

This paper describes a technique to reconstruct the volumes of the human body. For this purpose, are introduced mathematical objects able to represent 3d shapes, called super quadrics. These objects are positioned in the space according the captures made by a Microsoft Kinect device and are composed to represent the volumes of the human body. The employment of quaternions provides a relevant speedup for the rotation of the volumes and allows to follow the human movements in real time and reduced computational cost.

Reverse Rotation of the Kidney associated with vascular anomaly producing ipsilateral ureteropelvic junction obstrution

2009

Rotazione del personale nelle amministrazioni pubbliche e politiche contrasto alla corruzione: la prospettiva dell’ANAC

2021

In the last decade, the Italian State has included staff rotation within the framework of anti-corruption policies, providing precise indications on how to implement it and verifying its practical achievements in the national public administration system. The purpose of this article is to provide a framework of the theories and practices of staff rotation from the point of view of the law and the main acts of the National anti-Corruption Authority (ANAC). The article therefore develops as follows. A first part is dedicated to the presentation of the different types of staff rotation. A second part deals with the principles guiding the reorganization actions by rotation of public administrat…

On the history of torsional stress concentrations in shafts: From electrical analogies to numerical methods

2014

This article proposes a retrospective on experimental and numerical methods developed throughout the past century to solve the torsion problem in shafts, with particular emphasis on the determination of shear stress concentration factors in discontinuities of typical use in shaft design. This article, in particular, presents the theory and related solutions distinguishing between two classes of geometries: shafts with constant cross section and axisymmetric shafts with variable diameter. Emphasis is given to approaches based on physical analog methods and, in particular, those based on electrical analogies proposed since about 1925. Experimental methods based on structural physical models …

Red Cell Interactions with the Microcirculation

1976

We have measured RBC velocity profiles for mammalian arterioles and venules from high-speed cinematographic motion pictures. Measurements were made at 320× and 400× optical magnification over an averaging time period of 10 ms. In vivo profiles are uniformly nonsymmetrical, the RBCs exhibit rotation, and they frequently deviate sidewise from the overall axial direction of motion. In general, this is more pronounced on the venous side. Since all of the profiles are time variant and the average values are synchronous with the midstream velocity, individual RBC velocities will vary about the average. Profiles become more blunted in vessels with smaller diameters. In vessels below 16 μm diameter…

Axisymmetric simulations of magnetorotational core collapse: approximate inclusion of general relativistic effects

2006

We continue our investigations of the magnetorotational collapse of stellar cores discussing simulations performed with a modified Newtonian gravitational potential that mimics general relativistic effects. The approximate TOV potential used in our simulations catches several features of fully relativistic simulations quite well. It is able to correctly reproduce the behavior of models which show a qualitative change both of the dynamics and the gravitational wave signal when switching from Newtonian to fully relativistic simulations. If this is not the case, the Newtonian and the approximate TOV models differ quantitatively. The collapse proceeds to higher densities with the approximate TO…

Long-term FRII jet evolution: Clues from three-dimensional simulations

2018

We present a long-term numerical three-dimensional simulation of a relativistic outflow designed to be compared with previous results from axisymmetric, two-dimensional simulations, with existing analytical models and state-of-art observations. We follow the jet evolution from 1~kpc to 200~kpc, using a relativistic gas equation of state and a galactic profile for the ambient medium. We also show results from smaller scale simulations aimed to test convergence and different three-dimensional effects. We conclude that jet propagation can be faster than expected from axisymmetric simulations, covering tens of kiloparsecs in a few million years, until the dentist drill effect produced by the gr…

Sampling procedure in a willow plantation for chemical elements important for biomass combustion quality

2015

Willow (Salix spp.) is expected to contribute significantly to the woody bioenergy system in the future, so more information on how to sample the quality of the willow biomass is needed. The objectives of this study were to investigate the spatial variation of elements within shoots of a willow clone ‘Tordis’, and to reveal the relationship between sampling position, shoot diameters, and distribution of elements. Five Tordis willow shoots were cut into 10–50 cm sections from base to top. The ash content and concentration of twelve elements (Al, Ca, Cd, Cu, Fe, K, Mg, Mn, Na, P, Si, and Zn) in each section were determined. The results showed large spatial variation in the distribution of mos…