scholarly journals Constraining higher-order parameters for primordial non-Gaussianities from power spectra and bispectra of imaging surveys

2016 ◽  
Vol 93 (10) ◽  
Author(s):  
Ichihiko Hashimoto ◽  
Atsushi Taruya ◽  
Takahiko Matsubara ◽  
Toshiya Namikawa ◽  
Shuichiro Yokoyama
Geophysics ◽  
1983 ◽  
Vol 48 (10) ◽  
pp. 1409-1410 ◽  
Author(s):  
Robert Owen Plaisted ◽  
Hugo Gustavo Peña

Higher order auto‐spectra, in particular bispectra and perhaps trispectra, are being used increasingly for analyzing various nonlinear interactions in the ocean, e.g., Herring (1980) and McComas and Briscoe (1980). The resolution of these spectra, as with conventional energy spectra, is frequently limited because short data records must be used. The purpose of this note is to present a maximum entropy (MEM) representation for higher order auto‐spectra which has the advantage of the superior resolving power of the MEM technique under these circumstances. The derivation is a generalizaton of the power spectra derived for a linear process (Box and Jenkins, 1970). We derive an MEM representation for bispectra and show that this result can be generalized to auto‐spectra of any order.


2014 ◽  
Vol 90 (6) ◽  
Author(s):  
Tao Zhu ◽  
Anzhong Wang ◽  
Gerald Cleaver ◽  
Klaus Kirsten ◽  
Qin Sheng

2019 ◽  
Vol 43 (3) ◽  
pp. 568-585 ◽  
Author(s):  
Saeid Ghouli ◽  
Majid R. Ayatollahi ◽  
Morteza Nejati

2006 ◽  
Vol 97 (25) ◽  
Author(s):  
Y. Tokunaga ◽  
D. Aoki ◽  
Y. Homma ◽  
S. Kambe ◽  
H. Sakai ◽  
...  

1993 ◽  
Vol 03 (03) ◽  
pp. 551-557 ◽  
Author(s):  
VINOD CHANDRAN ◽  
STEVE ELGAR ◽  
CHARLES PEZESHKI

Higher-order spectral (bispectral and trispectral) analyses of numerical solutions of the Duffing equation with a cubic stiffness are used to isolate the coupling between the triads and quartets, respectively, of nonlinearly interacting Fourier components of the system. The Duffing oscillator follows a period-doubling intermittency catastrophic route to chaos. For period-doubled limit cycles, higher-order spectra indicate that both quadratic and cubic nonlinear interactions are important to the dynamics. However, when the Duffing oscillator becomes chaotic, global behavior of the cubic nonlinearity becomes dominant and quadratic nonlinear interactions are weak, while cubic interactions remain strong. As the nonlinearity of the system is increased, the number of excited Fourier components increases, eventually leading to broad-band power spectra for chaos. The corresponding higher-order spectra indicate that although some individual nonlinear interactions weaken as nonlinearity increases, the number of nonlinearly interacting Fourier modes increases. Trispectra indicate that the cubic interactions gradually evolve from encompassing a few quartets of Fourier components for period-1 motion to encompassing many quartets for chaos. For chaos, all the components within the energetic part of the power spectrum are cubically (but not quadratically) coupled to each other.


Author(s):  
Bozo Vazic ◽  
Bilen Emek Abali ◽  
Hua Yang ◽  
Pania Newell

AbstractEven though heterogeneous porous materials are widely used in a variety of engineering and scientific fields, such as aerospace, energy-storage technology, and bio-engineering, the relationship between effective material properties of porous materials and their underlying morphology is still not fully understood. To contribute to this knowledge gap, this paper adopts a higher-order asymptotic homogenization method to numerically investigate the effect of complex micropore morphology on the effective mechanical properties of a porous system. Specifically, we use the second-order scheme that is an extension of the first-order computational homogenization framework, where a generalized continuum enables us to introduce length scale into the material constitutive law and capture both pore size and pore distribution. Through several numerical case studies with different combinations of porosity, pore shapes, and distributions, we systematically studied the relationship between the underlying morphology and effective mechanical properties. The results highlight the necessity of higher-order homogenization in understanding the mechanical properties and reveal that higher-order parameters are required to capture the role of realistic pore morphologies on effective mechanical properties. Furthermore, for specific pore shapes, higher-order parameters exhibit dominant influence over the first-order continuum.


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