6,595 research outputs found

    Fractals in the Nervous System: conceptual Implications for Theoretical Neuroscience

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    This essay is presented with two principal objectives in mind: first, to document the prevalence of fractals at all levels of the nervous system, giving credence to the notion of their functional relevance; and second, to draw attention to the as yet still unresolved issues of the detailed relationships among power law scaling, self-similarity, and self-organized criticality. As regards criticality, I will document that it has become a pivotal reference point in Neurodynamics. Furthermore, I will emphasize the not yet fully appreciated significance of allometric control processes. For dynamic fractals, I will assemble reasons for attributing to them the capacity to adapt task execution to contextual changes across a range of scales. The final Section consists of general reflections on the implications of the reviewed data, and identifies what appear to be issues of fundamental importance for future research in the rapidly evolving topic of this review

    Road network dimension and average journey length: Measuring network efficiency with fractal geometry

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    Urban transport has been inefficient and its energy usage and emissions have been a major source of the global environmental destruction. This is largely because land-uses have been segregated, and thus journey length has increased to the extent that essential services have been too far. International discussion has concluded that the compact city is a possible solution, which many governments have adopted without enough verification. Even the definition of compact city is not yet clear. In this thesis, I use the concept of fractal city as an analytical method of the need to travel in cities, as well as a design theory of sustainable develop-ment to reduce the travel need. Indeed, this concept represents the city's internal efficiency through the 'fine grain' of street pattern to which Jane Jacobs has given the name and many urban designers have tried to visu-alise since then. The concept of fractal dimension is used to analyse the efficiency of the city's road network by desktop GIS, while that of generator is used to describe the design rationale of sustainable development. Therefore, I will postulate that fractal dimension represents the city's efficien¬cy. The average journey length is used as an indicator of transport efficiency of the city to demonstrate the hypothesis. The results of the analysis shows a high correlation (r2=0.658), compared to the other factors such as density (r2=0.493) in English contex
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