Centroid

About: Centroid is a research topic. Over the lifetime, 4110 publications have been published within this topic receiving 53637 citations. The topic is also known as: barycenter (geometry) & geometric center of a plane figure.

Effects of the inversion layer centroid on MOSFET behavior

Abstract: The effects of the average inversion-layer penetration, the inversion-layer centroid, on the inversion-charge density and the gate-to-channel capacitance have been analyzed. The quantum model has been used, and a variety of data have been obtained by self-consistently solving the Poisson and Schrodinger equations. An empirical expression for the centroid position that is valid for a wide range of electrical and technological variables has been obtained and has been applied to accurately model the inversion-layer density and capacitance.

Velocity field statistics in star-forming regions. I. Centroid velocity observations

Abstract: The probability density functions (pdfs) of molecular line centroid velocity fluctuations, and of line centroid velocity fluctuation differences at different spatial lags, are estimated for several nearby molecular clouds with active internal star formation. The data consist of over 75,000 13CO line profiles divided among 12 spatially and/or kinematically distinct regions. These regions range in size from less than 1 to more than 40 pc and are all substantially supersonic, with centroid fluctuation Mach numbers ranging from about 1.5 to 7. The centroid pdfs are constructed using three different types of estimators. Although three regions (all in Mon R2) exhibit nearly Gaussian centroid pdfs, the other regions show strong evidence for non-Gaussian pdfs, often nearly exponential, with possible evidence for power-law contributions in the far tails. Evidence for nearly exponential centroid pdfs in the neutral H I component of the interstellar medium is also presented, based on older published data for optical absorption lines and H I emission and absorption lines. These strongly non-Gaussian pdfs disagree with the nearly Gaussian behavior found for incompressible turbulence (except possibly shear flow turbulence) and simulations of decaying mildly supersonic turbulence. Spatial images of the largest magnitude centroid velocity differences for the star-forming regions appear less filamentary than predicted by decay simulations dominated by vortical interactions. No evidence for the scaling of difference pdf kurtosis with Reynolds number, as found in incompressible turbulence experiments and simulations, is found. We conclude that turbulence in both star-forming molecular clouds and diffuse H I regions involves physical processes that are not adequately captured by incompressible turbulence or by mildly supersonic decay simulations. The variation with lag of the variance and kurtosis of the difference pdfs is presented as a constraint on future simulations, and we evaluate and discuss the implications of the large scale and Taylor scale Reynolds numbers for the regions studied here.

Computing the centroid of a general type-2 fuzzy set by means of the centroid-flow algorithm

Abstract: Previous studies have shown that the centroid of a general type-2 fuzzy set (T2 FS) A can be obtained by taking the union of the centroids of all the α-planes (each raised to level α) of A. Karnik-Mendel (KM) or the enhanced KM (EKM) algorithms are used to compute the centroid of each α-plane. The iterative features in KM/EKM algorithms can be time-consuming, especially when the algorithms have to be repeated for many α-planes. This paper proposes a new method named centroid-flow (CF) algorithm to compute the centroid of A without having to apply KM/EKM algorithms for every α-plane. Extensive simulations have shown that the CF algorithm can reduce the computation time by 75%-80 % and 50% -75%, compared with KM and EKM algorithms, respectively, and still maintains satisfactory computation accuracy for various T2 FSs when the primary variable x and α -plane are discretized finely enough.

Know What Your Neighbors Do: 3D Semantic Segmentation of Point Clouds

Abstract: In this paper, we present a deep learning architecture which addresses the problem of 3D semantic segmentation of unstructured point clouds. Compared to previous work, we introduce grouping techniques which define point neighborhoods in the initial world space and the learned feature space. Neighborhoods are important as they allow to compute local or global point features depending on the spatial extend of the neighborhood. Additionally, we incorporate dedicated loss functions to further structure the learned point feature space: the pairwise distance loss and the centroid loss. We show how to apply these mechanisms to the task of 3D semantic segmentation of point clouds and report state-of-the-art performance on indoor and outdoor datasets.

Robust digital image watermarking method against geometrical attacks

Abstract: This paper proposes a new image watermarking scheme which is robust to RST attacks with cropping by improving Fourier-Mellin transform based watermarking (FMW). The proposed scheme reorders and modifies function blocks of FMW for improvement of realization and performance. Unlike FMW, our method uses log-polar map (LPM) in the spatial domain for scaling invariance, while translation invariance is provided by the use of an invariant centroid (IC) as the origin of LPM. IC is a gravity center of a central area on gray scale image that is invariant although an image is attacked by RST. For this, its calculation method is proposed. Also since LPM includes the property which transforms rotation of Cartesian coordinates system into a cyclic shift, 2-D DFT is performed on the LPM image and the magnitude spectrum extracted to provide a domain that is rotation invariant. The resulting domain, which is invariant to RST, is then used as the watermark-embedding domain. Furthermore, to prevent the watermarked image from degrading due to the coordinate system conversion, only LPM image of watermark signal is inverse mapped to Cartesian coordinates and add to the original image. Experimental results demonstrate that the proposed scheme is robust to RST attacks.