Living on the edge of chaos: minimally nonlinear models of genetic regulatory dynamics

Linearized catalytic reaction equations modeling e.g. the dynamics of genetic regulatory networks under the constraint that expression levels, i.e. molecular concentrations of nucleic material are positive, exhibit nontrivial dynamical properties, which depend on the average connectivity of the reaction network. In these systems the inflation of the edge of chaos and multi-stability have been demonstrated to exist. The positivity constraint introduces a nonlinearity which makes chaotic dynamics possible. Despite the simplicity of such minimally nonlinear systems, their basic properties allow to understand fundamental dynamical properties of complex biological reaction networks. We analyze the Lyapunov spectrum, determine the probability to find stationary oscillating solutions, demonstrate the effect of the nonlinearity on the effective in- and out-degree of the active interaction network and study how the frequency distributions of oscillatory modes of such system depend on the average connectivity.Comment: 11 pages, 5 figure

Where did the ?new urban economics? go?

The notion of the ?New Urban Economics? emerged in the late 1960s as more rigorous approaches were applied to what had largely hitherto been an essentially descriptive approach to analyzing urban economies. The application of mathematical methods to urban problems offered the prospect of both a more thorough understanding of how urban economic systems function and a basis upon which frameworks could be developed for quantitative testing of alternative ideas. The aim of this paper is to examine the extent to which this new approach has lived up to initial expectations and degree to which modern urban economics has managed to circumvent some of the earlier criticisms raised against it. It also assesses the extent to which the new urban economics has fulfilled its promise of allowing greater quantification of urban parameters as aids to policy making

CAHRS hrSpectrum (November-December 2008)

HRSpec2008_12.pdf: 478 downloads, before Oct. 1, 2020

Networks: open, closed or complex. Connecting philosophy, design and innovation, part 3

This is the third and final paper of a series bringing a philosophical investigation to matters of design and innovation. With the others examining: first, the urges to reconsider innovation from a creative, specifically design, direction (‘Beyond Success’); and second, the type of dynamic innovation that may be thus reconsidered (‘Ecstatic Innovation’); this paper will investigate a way of constructing this type of design-driven innovation. It will begin by looking at the networks that can be created to deliver a dynamic, continually innovative innovation and will start by considering two concepts of network: the open and the closed. While there seems to be an easy distinction to be made between open and closed, and its mapping onto similarly convenient ideas of good and bad, I hope to show that this is not the case. The complexity of networked forms of organisation demand that we bring to them a complexity of thought that comes from philosophy. Nevertheless, such an account will also need to engage with discourses from other disciplinary areas: notably organisational theory, innovation management and design. The outcome is of importance to thinking the organisational structures in which innovation is managed

Corporate strategy revisited: A view from complexity theory

Despite its long tradition and well known contributions, corporate strategy research is yet far from being mature. This paper proposes an innovative framework that approaches the field from the theoretical perspective provided by complexity theory. We propose to see the corporate level of the organization as the driver, pacer and framer of the overall firm's evolution process. Drive is provided by the cognitive representation of the corporate fitness landscape that is implicit in the firm's corporate plan. Pacing is a consequence of the kind of strategic initiatives ("search strategy") developed by the company. Framing is achieved through the architectural design that the corporate level implements for the firm.corporate strategy; complexity theory; self-organizing;