Finite-Rank Multivariate-Basis Expansions of the Resolvent Operator as a Means of Solving the Multivariable Lippmann-Schwinger Equation for Two-Particle Scattering

Cataloged from PDF version of article.Finite-rank expansions of the two-body resolvent operator are explored as a tool for calculating the full three-dimensional two-body T-matrix without invoking the partial-wave decomposition. The separable expansions of the full resolvent that follow from finite-rank approximations of the free resolvent are employed in the Low equation to calculate the T-matrix elements. The finite-rank expansions of the free resolvent are generated via projections onto certain finite-dimensional approximation subspaces. Types of operator approximations considered include one-sided projections (right or left projections), tensor-product (or outer) projection and inner projection. Boolean combination of projections is explored as a means of going beyond tensor-product projection. Two types of multivariate basis functions are employed to construct the finite-dimensional approximation spaces and their projectors: (i) Tensor-product bases built from univariate local piecewise polynomials, and (ii) multivariate radial functions. Various combinations of approximation schemes and expansion bases are applied to the nucleon-nucleon scattering employing a model two-nucleon potential. The inner-projection approximation to the free resolvent is found to exhibit the best convergence with respect to the basis size. Our calculations indicate that radial function bases are very promising in the context of multivariable integral equations

Multi-variate Bateman method for two-body scattering without partial-wave decomposition

Cataloged from PDF version of article.The use of Bateman method for solving the two-variable version of the twobody Lippmann–Schwinger equation without recourse to partial-wave decomposition is investigated. Bateman method is based on a special kind of interpolation of the momentum representation of the potential on a multi-variate grid. A suitable scheme for the generation of a multi-variate Cartesian grid is described. The method is tested on the Hartree potential for electron-hydrogen scattering in the static no-exchange approximation. Our results show that the Bateman method is capable of producing quite accurate solutions with relatively small number of grid points

Construction informatics in Turkey: strategic role of ICT and future research directions

Construction Informatics deals with subjects ranging from strategic management of ICTs to interoperability and information integration in the construction industry. Studies on defining research directions for Construction Informatics have a history over 20 years. The recent studies in the area highlight the priority themes for Construction Informatics research as interoperability, collaboration support, intelligent sites and knowledge sharing. In parallel, today it is widely accepted in the Architecture/Engineering/Construction (AEC) industry that ICT is becoming a strategic asset for any organisation to deliver business improvement and achieve sustainable competitive advantage. However, traditionally the AEC industry has approached investing in ICT with a lack of strategic focus and low level of priority to the business. This paper presents a recent study from Turkey that is focused on two themes. The first theme investigates the strategic role of ICT implementations from an industrial perspective, and explores if organisations within the AEC industry view ICT as a strategic resource for their business practice. The second theme investigates the ‘perspective of academia’ in terms of future research directions of Construction Informatics. The results of the industrial study indicates that ICT is seen as a value-adding resource, but a shift towards the recognition of the importance of ICT in terms of value adding in winning work and achieving strategic competitive advantage is observed. On the other hand, ICT Training is found to be the theme of highest priority from the academia point of view

Avoiding Stffness: Perspectives of agile technology diffusion

The increased pervasiveness of Information and Communication Technology (ICT) within the Architecture Engineering and Construction (AEC) sector, not only introduces unparalleled opportunities for enhancing the performance of design/engineering/construction processes per se, but also serves as a unique lever for improving and delivering overall competitiveness. However, whilst the onset and evolution of ICT keeps improving, it is also recognised that organisations often fail to match this evolution, most notably through the adoption, diffusion and dissemination of this technology. This has also been acknowledged as a barrier, particularly concerning innovation opportunities. Cognisant of this, organisations are increasingly looking to secure full advantage of emerging ICT developments. On this theme, this study identifies a series of priority areas for organisations, with the specific remit of securing agility (in the market) through ICT diffusion. A questionnaire, based on an Agile-Technology Diffusion framework, was used to capture the perceptions of management professionals working in the Turkish AEC sector. The ranking analysis of the survey results and comparison of the different management perceptions (levels) are presented for discussion. Research findings identify several priority areas that need to be addressed. These findings also uncover significant differences in the perceptions of different management levels - which can help decision makers appreciate the holistic interdependencies, especially the factors which impinge (or impede) overall competitiveness

An Emotional Economy of Mundane Objects

Cataloged from PDF version of article.This article illuminates the affective potentialities of objects. We examine the circulation of Kurdish music cassettes in Turkey during the restrictive and strife-laden period of the 1970s, 1980s, and 1990s. We find that the practices comprising circulation - recording, hiding, playing, and exchanging cassettes - constituted tactical resistance and generated communal imaginaries. We illuminate the "emotional economy" that is animated by a mundane object: the cassette, through its circulation, becomes saturated with emotions, establishes shared emotional repertoires, and habituates individuals and collectives into common emotional dispositions. Cassettes thus play a part in shaping and reinforcing an emotional habitus that accompanies the emergence of a sense of "us," the delineation of the "other," and the relationship between the two. We thus demonstrate the entwinement of materiality and emotions, and examine how this entwinement generates emotional structures that shape and perpetuate the imagining of community as well as the enactment of resistance

Construction informatics in Turkey: strategic role of ICT and future research directions

Construction Informatics deals with subjects ranging from strategic management of ICTs to interoperability and information integration in the construction industry. Studies on defining research directions for Construction Informatics have a history over 20 years. The recent studies in the area highlight the priority themes for Construction Informatics research as interoperability, collaboration support, intelligent sites and knowledge sharing. In parallel, today it is widely accepted in the Architecture/Engineering/Construction (AEC) industry that ICT is becoming a strategic asset for any organisation to deliver business improvement and achieve sustainable competitive advantage. However, traditionally the AEC industry has approached investing in ICT with a lack of strategic focus and low level of priority to the business. This paper presents a recent study from Turkey that is focused on two themes. The first theme investigates the strategic role of ICT implementations from an industrial perspective, and explores if organisations within the AEC industry view ICT as a strategic resource for their business practice. The second theme investigates the ‘perspective of academia’ in terms of future research directions of Construction Informatics. The results of the industrial study indicates that ICT is seen as a value-adding resource, but a shift towards the recognition of the importance of ICT in terms of value adding in winning work and achieving strategic competitive advantage is observed. On the other hand, ICT Training is found to be the theme of highest priority from the academia point of view

Modelling SAR with a Generalisation of the Rayleigh Distribution

Synthetic aperture radar (SAR) imagery has found important applications since its introduction, due to its clear advantage over optical satellite imagery, being operable in various weather conditions. However, due to the physics of radar imaging process, sar images contain unwanted artefacts in the form of a granular look which is called speckle. the assumptions of the classical SAR image generation model lead to the convention that the real and imaginary parts of the received wave follow a Gaussian law, which in turn means that the amplitude of the wave has a Rayleigh distribution- . However, some experimental data show impulsive characteristics which correspond to underlying heavy-tailed distributions, clearly non-rayleigh. some alternative distributions have been suggested such as weibull and log-normal distributions, however, in most of the cases these models are empirical, not derived with the consideration of underlying physical conditions and therefore are case specific. In this report, relaxing some of the assumptions leading to the classical rayleigh model and using the recent results in the literature on $\alpha$-stable distributions, we develop a generalised (heavy-tailed) version of the rayleigh model based on the assumption that the real and the imaginary parts of the received signal follows an isotropic $\alpha$-stable law which is suggested by a generalised form of the central limit theorem. we also derive novel methods for the estimation of the heavy-tailed rayleigh distribution parameter- s based on negative fractional-order statistics for model fitting. our experimental results show that the heavy-tailed rayleigh model can describe a wide range of data which could not be described by the classical rayleigh model