Detecting and Assessing the Problems Caused by Multi-Collinearity: A Useof the Singular-Value Decomposition

This paper presents a means for detecting the presence of multicollinearity and for assessing the damage that such collinearity may cause estimated coefficients in the standard linear regression model. The means of analysis is the singular value decomposition, a numerical analytic device that directly exposes both the conditioning of the data matrix X and the linear dependencies that may exist among its columns. The same information is employed in the second part of the paper to determine the extent to which each regression coefficient is being adversely affected by each linear relation among the columns of X that lead to its ill conditioning.

Gravitation as a Plastic Distortion of the Lorentz Vacuum

In this paper we present a theory of the gravitational field where this field (a kind of square root of g) is represented by a (1,1)-extensor field h describing a plastic distortion of the Lorentz vacuum (a real substance that lives in a Minkowski spacetime) due to the presence of matter. The field h distorts the Minkowski metric extensor in an appropriate way (see below) generating what may be interpreted as an effective Lorentzian metric extensor g and also it permits the introduction of different kinds of parallelism rules on the world manifold, which may be interpreted as distortions of the parallelism structure of Minkowski spacetime and which may have non null curvature and/or torsion and/or nonmetricity tensors. We thus have different possible effective geometries which may be associated to the gravitational field and thus its description by a Lorentzian geometry is only a possibility, not an imposition from Nature. Moreover, we developed with enough details the theory of multiform functions and multiform functionals that permitted us to successfully write a Lagrangian for h and to obtain its equations of motion, that results equivalent to Einstein field equations of General Relativity (for all those solutions where the manifold M is diffeomorphic to R^4. However, in our theory, differently from the case of General Relativity, trustful energy-momentum and angular momentum conservation laws exist. We express also the results of our theory in terms of the gravitational potential 1-form fields (living in Minkowski spacetime) in order to have results which may be easily expressed with the theory of differential forms. The Hamiltonian formalism for our theory (formulated in terms of the potentials) is also discussed. The paper contains also several important Appendices that complete the material in the main text.Comment: Misprints and typos have been corrected, Chapter 7 have been improved. Appendix E has been reformulated and Appendix F contains new remarks which resulted from a discussion with A. Lasenby. A somewhat modified version has been published in the Springer Series: Fundamental Theories of Physics vol. 168, 2010. http://www.ime.unicamp.br/~walrod/plastic2014.pd

Corporate Real Estate Management in the Retail Sector: Investigation of Current Strategy and Structure

Retail organizations are often cited as being at the forefront of corporate real estate management. This research found that the retail sector is characterized by diversity both in terms of the degree to which organizations are vertically integrated and in terms of the range of modes of retailing they engage in. This in turn led to diverse real estate portfolios. However, regardless of this diversity, the over riding strategy was focused on supporting the core activity. This study provides a snapshot of current practice however it also uncovers the need for a greater understanding of the diversity in practice.

Friction and Inertia: Business Change, Corporate Real Estate Portfolios and the U.K. Office Market

It has been asserted that business reorganization and new working practices are transforming the nature of demand for business space. Downsizing, delayering, business process re-engineering and associated initiatives alter the amount, type and location of space required by firms. The literature has neglected the impact of real estate market structures on the ability of organizations to implement these new organizational forms or contemporary working practices successfully. Drawing from research in the United Kingdom, the article demonstrates that, while new working practices are widespread, their impact on the corporate real estate portfolio is less dramatic than often supposed. In part, this is attributed to inflexibility in market structures, which constrains the supply of appropriate space.