The Effect of Entry by Wal-Mart Supercenters on Retail Grocery Concentration

The U.S. retail grocery industry shifted from an industry dominated by small grocers serving local markets to one characterized by large retailers present in international markets. Average retail grocery concentration as measured by CR4 increased from 19.9 in 1997 to 31.0 in 2002 (U.S. Department of Commerce, Bureau of the Census, 2000; 2005). Wal-Mart’s tremendous growth is the catalyst to this change, but little is known about Wal-Mart’s effect on market concentration. This analysis evaluates the effects of de novo entry by Wal-Mart Supercenters on retail grocery concentration. The effect of Wal-Mart Supercenters on changes in retail grocery concentration is estimated using econometric modeling. The results show that existing Wal-Mart Supercenter operations and entry by Wal-Mart Supercenters significantly increase the rate of change in retail grocery concentration.Agribusiness, Industrial Organization,

A theory of structural model validity in simulation.

During the last decennia, the practice of simulation has become increasingly popular among many system analysts, model builders and general scientists for the purpose of studying complex systems that surpass the operability of analytical solution techniques. As a consequence of the pragmatic orientation of simulation, a vital stage for a successful application is the issue of validating a constructed simulation model. Employing the model as an effective instrument for assessing the benefit of structural changes or for predicting future observations makes validation an essential part of any productive simulation study. The diversity of the employment field of simulation however brings about that there exists an irrefutable level of ambiguity concerning the principal subject of this validation process. Further, the literature has come up with a plethora of ad hoc validation techniques that have mostly been inherited from standard statistical analysis. It lies within the aim of this paper to reflect on the issue of validation in simulation and to present the reader with a topological parallelism of the classical philosophical polarity of objectivism versus relativism. First, we will position validation in relation to verification and accreditation and elaborate on the prime actors in validation, i.e. a conceptual model, a formal model and behaviour. Next, we will formally derive a topological interpretation of structural validation for both objectivists and relativists. As will be seen, recent advances in the domain of fuzzy topology allow for a valuable metaphor of a relativistic attitude towards modelling and structural validation. Finally, we will discuss several general types of modelling errors that may occur and examine their repercussion on the natural topological spaces of objectivists and relativists. We end this paper with a formal, topological oriented definition of structural model validity for both objectivists and relativists. The paper is concluded with summarising the most important findings and giving a direction for future research.Model; Simulation; Theory; Scientists; Processes; Statistical analysis;

Why must we work in the phase space?

We are going to prove that the phase-space description is fundamental both in the classical and quantum physics. It is shown that many problems in statistical mechanics, quantum mechanics, quasi-classical theory and in the theory of integrable systems may be well-formulated only in the phase-space language.Comment: 130 page

On the Hyperbolicity of Lorenz Renormalization

We consider infinitely renormalizable Lorenz maps with real critical exponent $\alpha>1$ and combinatorial type which is monotone and satisfies a long return condition. For these combinatorial types we prove the existence of periodic points of the renormalization operator, and that each map in the limit set of renormalization has an associated unstable manifold. An unstable manifold defines a family of Lorenz maps and we prove that each infinitely renormalizable combinatorial type (satisfying the above conditions) has a unique representative within such a family. We also prove that each infinitely renormalizable map has no wandering intervals and that the closure of the forward orbits of its critical values is a Cantor attractor of measure zero.Comment: 63 pages; 10 figure

THE EFFECT OF ENTRY BY WAL-MART SUPERCENTERS ON RETAIL GROCERY CONCENTRATION

The U.S. retail grocery industry shifted from an industry dominated by small grocers serving local markets to one characterized by large retailers present in international markets. Average retail grocery concentration as measured by CR4 increased from 17.8 in 1982 to 43.0 in 1999 (U.S. Census Bureau, 1982; Trade Dimensions Marketing Guidebook, 2000). Wal-Mart's tremendous growth is the catalyst to this change. Although Wal-Mart has been studied from multiple perspectives, little is known about Wal-Mart's effect on market concentration. Understanding Wal-Mart's influence on market concentration is important because an extensive literature shows a pattern linking retail grocery market concentration to increases in retail grocery prices. The objective of this analysis is to evaluate the effects of de novo entry by Wal-Mart Supercenters on retail grocery concentration (CR4). Using a panel dataset complied from Trade Dimensions Marketing Guidebook and Market Scope publications, the effect of Wal-Mart Supercenters on changes in retail grocery concentration was estimated. The results show that existing Wal-Mart Supercenter operations and entry by Wal-Mart Supercenters significantly increase the rate of change in retail grocery concentration as measured by CR4.Marketing,

Effects of Supply Chain Management for Food and Grocery Companies

Mass merchandisers’ entry into food retailing threatens traditional grocers’ market share. In response, traditional grocers and food manufacturers adopted Efficient Consumer Response (ECR) as an industry-wide set of supply chain management strategies that focused on cutting costs and improving product assortment, thereby improving inventory and financial performance levels. However, research findings and trade press reports question whether adopting supply chain management strategies will achieve these goals. The results of this analysis strongly support the proposition that the adoption of an ECR strategy pays off. However, the growth in profit does not appear to come from improved performance for traditional inventory measures. The driving force behind these improved financial measures can be attributed to the cash conversion cycle. Thus, the time spent in developing close relationships with buyers or suppliers and the investments in information technology have been justified. Size matters; ECR is more effective due to economies of scale and information technology. However, this may lead to more consolidations because all firms may not have sufficient capital to invest in ECR initiatives. In short, to remain competitive ECR strategies should strongly be considered by firms that are lagging in implementation.Efficient Consumer Response, supply chain management, inventory, cash conversion cycles, financial performance, grocery, food manufacturing, Financial Economics, Industrial Organization,

Basins of Attraction for Chimera States

Chimera states---curious symmetry-broken states in systems of identical coupled oscillators---typically occur only for certain initial conditions. Here we analyze their basins of attraction in a simple system comprised of two populations. Using perturbative analysis and numerical simulation we evaluate asymptotic states and associated destination maps, and demonstrate that basins form a complex twisting structure in phase space. Understanding the basins' precise nature may help in the development of control methods to switch between chimera patterns, with possible technological and neural system applications.Comment: Please see Ancillary files for the 4 supplementary videos including description (PDF