Processing Of Collocations Research Articles

Incremental displacement collocation method for the evaluation of tension softening curve of mortar

The tension softening curve (TSC), showing the relationship between the cohesive tensile stress and crack opening displacement, is the constitutive law of the cohesive crack model. Due to the difficulties in measuring local deformations around the crack tip, the TSC is usually determined inversely from the global responses such as load–deflection curve or load–crack mouth opening displacement curve of pre-notched specimens. However, the use of global responses alone in the inverse analysis usually causes problems that may affect the reliability and accuracy of the TSC which is basically a local material property. To overcome these limitations, an incremental displacement collocation method (IDCM) that is able to evaluate the TSC in a step-by-step manner is proposed in this paper. Both global and local responses of a pre-notched mortar beam, which are measured using an electronic speckle pattern interferometry technique, are used in the displacement collocation process. Furthermore, the finite element model (FEM) is utilized to simulate the response of the beam. The TSCs evaluated in this study are verified through the comparisons of the global and local displacements as well as the fracture energy. A tri-linear curve was found to be the best approximation of the TSC of mortar.

Electrophysiological evidence of interaction between contextual expectation and semantic integration during the processing of collocations

Despite the potentially infinite creativity of language, many words are patterned in ordered strings called collocations. Final words of these clusters are highly predictable; in addition, their overall meaning can vary on the literality dimension, ranging from (figurative) idiomatic strings to literal strings. These structures thus offer a natural linguistic scenario to contrast ERP correlates of contextual expectation and semantic integration processes during comprehension. In this study, expected endings elicited a positive peak around 300ms compared to less expected synonyms, suggesting that the earlier recognition of the string leads to the specific pre-activation of the lexical items that conclude the expression. On the other hand, meaning variations of these fixed strings (either a literal or a figurative whole meaning) affected ERPs only around 400ms, i.e. in the frontal portion of the N400. These findings are discussed within a more general cognitive framework as outlined in Kok's (2001) dual categorization model.

Computationally Efficient Methods of Collocating Satellite, Aircraft, and Ground Observations

Abstract The usefulness of measurements from satellite-borne instruments is enhanced if these measurements can be compared to measurements from other instruments mounted aboard the same or different satellite, with measurements from aircraft, or with ground measurements. The process of associating measurements from disparate instruments and platforms is referred to as collocation. In a few cases, two instruments mounted aboard the same spacecraft have been engineered to function in tandem, but commonly this is not the case. The collocation process may then become an awkward geometric problem of finding which of many observations within one dataset corresponds to an observation in another set, possibly from another platform. This paper presents methods that can be applied to a wide range of satellite, aircraft, and surface measurements that allow for efficient collocation with measurements having varying spatial and temporal sampling. Examples of applying the methods are presented that highlight the benefits of efficient collocation. This includes identifying the occurrence of simultaneous nadir observations (SNOs); collocation of sounder, imager, and active remotely sensed measurements on the NASA Earth Observation System (EOS); and collocation of the polar orbiting imager, sounder, and microwave measurements with geostationary observations. It is possible, using an inexpensive laptop computer, to collocate Moderate Resolution Imaging Spectroradiometer (MODIS) imager observations from the Aqua satellite with geostationary observations rapidly enough to deal with these measurements in real time, making either dataset, enhanced by the other, a potentially operational product. A “tool kit” is suggested consisting of computer procedures useful in collocation.

Remote sensing of cirrus cloud vertical size profile using MODIS data

This paper describes an algorithm for inferring cirrus cloud top and cloud base effective particle sizes and cloud optical thickness from the Moderate Resolution Imaging Spectroradiometer (MODIS) 0.645, 1.64 and 2.13, and 3.75 μm band reflectances/radiances. This approach uses a successive minimization method based on a look‐up library of precomputed reflectances/radiances from an adding‐doubling radiative transfer program, subject to corrections for Rayleigh scattering at the 0.645 μm band, above‐cloud water vapor absorption, and 3.75 μm thermal emission. The algorithmic accuracy and limitation of the retrieval method were investigated by synthetic retrievals subject to the instrument noise and the perturbation of input parameters. The retrieval algorithm was applied to three MODIS cirrus scenes over the Atmospheric Radiation Measurement Program's southern Great Plain site, north central China, and northeast Asia. The reliability of retrieved cloud optical thicknesses and mean effective particle sizes was evaluated by comparison with MODIS cloud products and qualitatively good correlations were obtained for all three cases, indicating that the performance of the vertical sizing algorithm is comparable with the MODIS retrieval program. Retrieved cloud top and cloud base ice crystal effective sizes were also compared with those derived from the collocated ground‐based millimeter wavelength cloud radar for the first case and from the Cloud Profiling Radar onboard CloudSat for the other two cases. Differences between retrieved and radar‐derived cloud properties are discussed in light of assumptions made in the collocation process and limitations in radar remote sensing characteristics.

Chebyshev collocation solutions of the navier-stokes equations using multi-domain decomposition and finite element preconditioning

The steady Navier-Stokes equations are solved using series of basis functions involving Chebyshev polynomials. The projection method is a collocation scheme. A Newton's linearization is performed in order to obtain a set of algebraic equations. As the matrix system is ill conditioned, the collocation technique is preconditioned by a standard Galerkin finite element method using a 9-nodes Lagrangian element which presents decisive advantages: sparsity, reduced condition number, easy treatment of complicated geometries. To handle nontrivial geometries in the collocation process, a domain decomposition is set up. The treatment of interface conditions is fully described. Several test problems like the regularized driven square cavity and the backward facing step are discussed to show the abilities of the present algorithm.

Chebyshev collocation solutions of flow problems

Chebyshev collocation methods are reviewed. For general second-order elliptic equations, the algebraic system obtained through the collocation process is ill-conditioned. Recent work on finite element preconditioning shows that bilinear elements give full satisfaction. For Stokes problems, as interpolants of different degree are used for the velocity and the pressure, the classical nine-node Lagrangian element with biquadratic velocities and bilinear pressures constitutes the best choice. In order to treat the non-linear terms, a Newton's method is designed. Domain decomposition is set up with the jumps of the stress vector across interfaces between adjacent subdomains. Two-dimensional curvy geometries are handled by a coordinate mapping. Problems with singularities are treated by a mixed finite element and spectral approximation. Finally, current developments for Non-Newtonian fluids are evoked.

An Approximation Procedure for Nonsymmetric, Nonlinear Hyperbolic Systems with Integral Boundary Conditions

Optimal order error estimates for two linearizations of a collocation process using tensor products of continuous, piecewise linear functions in space and time are derived for a class of nonsymmetric, nonlinear hyperbolic systems with integral boundary conditions. This procedure is a variant of the so-called box scheme. Error estimates are also derived for a generalization of these procedures to collocation based on continuous, piecewise polynomials of degree r in space tensored with continuous, piecewise linear functions in time.