2,965 research outputs found

    Extension of Lorenz Unpredictability

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    It is found that Lorenz systems can be unidirectionally coupled such that the chaos expands from the drive system. This is true if the response system is not chaotic, but admits a global attractor, an equilibrium or a cycle. The extension of sensitivity and period-doubling cascade are theoretically proved, and the appearance of cyclic chaos as well as intermittency in interconnected Lorenz systems are demonstrated. A possible connection of our results with the global weather unpredictability is provided.Comment: 32 pages, 13 figure

    A Complexity Science Based Approach to Programme Risk Management

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    Programme management has rapidly gained acceptance as a vehicle for achieving organisational strategic objectives and as a means of aligning projects with the overall strategy of the organisation. Managing programme risk poses challenges which are different from those in project management. Attempts to modify and apply project risk management techniques to programme risk management have experienced difficulties. The implications of the challenges of programme risk management extend beyond the tools and techniques. Recent research shows that that programme management is neither an extension, nor a scaled up version of project management. Philosophically, a paradigm shift from the predominantly mechanistic and reductionist mindset to a more appropriate paradigm based on complexity science and the theory of complex adaptive systems is required. This leads to the conclusion that the classic event based view of risk is inappropriate in modelling and analysing programme risk which need to be treated as holistic and dynamic

    A Complexity Science Based Approach to Programme Risk Management

    Get PDF
    Programme management has rapidly gained acceptance as a vehicle for achieving organisational strategic objectives and as a means of aligning projects with the overall strategy of the organisation. Managing programme risk poses challenges which are different from those in project management. Attempts to modify and apply project risk management techniques to programme risk management have experienced difficulties. The implications of the challenges of programme risk management extend beyond the tools and techniques. Recent research shows that that programme management is neither an extension, nor a scaled up version of project management. Philosophically, a paradigm shift from the predominantly mechanistic and reductionist mindset to a more appropriate paradigm based on complexity science and the theory of complex adaptive systems is required. This leads to the conclusion that the classic event based view of risk is inappropriate in modelling and analysing programme risk which need to be treated as holistic and dynamic

    Lorenz, G\"{o}del and Penrose: New perspectives on determinism and causality in fundamental physics

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    Despite being known for his pioneering work on chaotic unpredictability, the key discovery at the core of meteorologist Ed Lorenz's work is the link between space-time calculus and state-space fractal geometry. Indeed, properties of Lorenz's fractal invariant set relate space-time calculus to deep areas of mathematics such as G\"{o}del's Incompleteness Theorem. These properties, combined with some recent developments in theoretical and observational cosmology, motivate what is referred to as the `cosmological invariant set postulate': that the universe UU can be considered a deterministic dynamical system evolving on a causal measure-zero fractal invariant set IUI_U in its state space. Symbolic representations of IUI_U are constructed explicitly based on permutation representations of quaternions. The resulting `invariant set theory' provides some new perspectives on determinism and causality in fundamental physics. For example, whilst the cosmological invariant set appears to have a rich enough structure to allow a description of quantum probability, its measure-zero character ensures it is sparse enough to prevent invariant set theory being constrained by the Bell inequality (consistent with a partial violation of the so-called measurement independence postulate). The primacy of geometry as embodied in the proposed theory extends the principles underpinning general relativity. As a result, the physical basis for contemporary programmes which apply standard field quantisation to some putative gravitational lagrangian is questioned. Consistent with Penrose's suggestion of a deterministic but non-computable theory of fundamental physics, a `gravitational theory of the quantum' is proposed based on the geometry of IUI_U, with potential observational consequences for the dark universe.Comment: This manuscript has been accepted for publication in Contemporary Physics and is based on the author's 9th Dennis Sciama Lecture, given in Oxford and Triest

    Learning democracy in social work

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    In this contribution, we discuss the role of social work in processes of democracy. A key question in this discussion concerns the meaning of ‘the social’ in social work. This question has often been answered in a self-referential way, referring to a methodological identity of social work. This defines the educational role of social work as socialisation (be it socialisation into obedience or into an empowered citizen). However, the idea of democracy as ‘ongoing experiment’ and ‘beyond order’ challenges this methodological identity of social work. From the perspective of democracy as an ‘ongoing experiment’, the social is to be regarded as a platform for dissensus, for ongoing discussions on the relation between private and public issues in the light of human rights and social justice. Hence, the identity of social work cannot be defined in a methodological way; social work is a complex of (institutionalized) welfare practices, to be studied on their underlying views on the ‘social’ as a political and educational concept, and on the way they influence the situation of children, young people and adults in society

    Predictability of the energy cascade in 2D turbulence

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    The predictability problem in the inverse energy cascade of two-dimensional turbulence is addressed by means of direct numerical simulations. The growth rate as a function of the error level is determined by means of a finite size extension of the Lyapunov exponent. For error within the inertial range, the linear growth of the error energy, predicted by dimensional argument, is verified with great accuracy. Our numerical findings are in close agreement with the result of TFM closure approximation.Comment: 3 pages, 3 figure
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