7,604 research outputs found

    Network Neutrality: A Research Guide

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    The conclusion in a research handbook should emphasise the complexity of the problem than trying to claim a one-size-fits-all solution. I have categorised net neutrality into positive and negative (content discrimination) net neutrality indicating the latter as potentially harmful. Blocking content without informing customers appropriately is wrong: if it says ‘Internet service’, it should offer an open Internet (alongside walled gardens if that is expressly advertised as such). The issue of uncontrolled Internet flows versus engineered solutions is central to the question of a ‘free’ versus regulated Internet. A consumer- and citizen-orientated intervention depends on passing regulations to prevent unregulated nontransparent controls exerted over traffic via DPI equipment, whether imposed by ISPs for financial advantage or by governments eager to use this new technology to filter, censor and enforce copyright against their citizens. Unraveling the previous ISP limited liability regime risks removing the efficiency of that approach in permitting the free flow of information for economic and social advantage. These conclusions support a light-touch regulatory regime involving reporting requirements and co-regulation with, as far as is possible, market-based solutions. Solutions may be international as well as local, and international coordination of best practice and knowledge will enable national regulators to keep up with the technology ‘arms race’

    Nonlinear Stability in Fluids and Plasmas

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    European Law and Regulation of Mobile Net Neutrality

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    Mobile is a rapidly growing and potentially major element of the future Internet, and its environment cannot be sensibly considered in isolation from fixed networks [2]. A note on terminology: Europe uses the term Mobile Network Operators (MNOs) while the United States uses 'wireless' Internet Service Providers (ISPs) [3]. 'Wireless' is somewhat more open in the United States. In Europe, mobile has always made special pleading for forms of self-regulation, as we will see. The article introduces mobile broadband, then considers net neutrality in the fixed environment including the new laws passed in November 2009 in the European Parliament, before considering the mobile net neutrality debate, the degree of price control regulation exerted on European mobiles and the MNOs' vigorous rear-guard anti-regulation defence. Finally, I look at the effects of this regulatory asymmetry and whether MNO calls for mobile to be treated differently from other ISPs can be justified. I conclude by examining what the effect of price and content control on mobile is likely to be for incentives for fixed ISPs and produce a result that I describe as the 'fixed' strategy

    Stability Analysis of a Rigid Body with a Flexible Attachment Using the Energy-Casimir Method

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    We consider a system consisting of a rigid body to which a linear extensible shear beam is attached. For such a system the Energy-Casimir method can be used to investigate the stability of the equilibria. In the case we consider, it can be shown that a test for (formal) stability reduces to checking the positive definiteness of two matrices which depend on the parameters of the system and the particular equilibrium about which the stability is to be ascertained

    Analysis of the retail survey of products that carry welfare- claims and of non-retailer led assurance schemes whose logos accompany welfare-claims.

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    This report serves two aims. Firstly, this report contains analysis of the retail audit (sub-deliverable 1.2.2.1) of welfare-friendly food products in the 6 study countries. The report gives the results of an emerging comparative analysis of the ‘market’ for welfare-friendly food products in the 6 study countries. It also outlines ‘non-retailer’ led schemes1 whose products occurred in the study. In this way, an emerging picture of the actual product ranges, that make claims about welfare-friendliness, will be drawn based on fieldwork carried out from November 2004 until April 2005. Also, the report explores how the different legislative and voluntary standards on animal welfare compare across different countries and how these actively advertise their welfare-friendlier component to consumers through food packaging. <br/

    A block diagonalization theorem in the energy-momentum method

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    We prove a geometric generalization of a block diagonalization theorem first found by the authors for rotating elastic rods. The result here is given in the general context of simple mechanical systems with a symmetry group acting by isometries on a configuration manifold. The result provides a choice of variables for linearized dynamics at a relative equilibrium which block diagonalizes the second variation of an augmented energy these variables effectively separate the rotational and internal vibrational modes. The second variation of the effective Hamiltonian is block diagonal. separating the modes completely. while the symplectic form has an off diagonal term which represents the dynamic interaction between these modes. Otherwise, the symplectic form is in a type of normal form. The result sets the stage for the development of useful criteria for bifurcation as well as the stability criteria found here. In addition, the techniques should apply to other systems as well, such as rotating fluid masses

    Discrete Routh Reduction

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    This paper develops the theory of abelian Routh reduction for discrete mechanical systems and applies it to the variational integration of mechanical systems with abelian symmetry. The reduction of variational Runge-Kutta discretizations is considered, as well as the extent to which symmetry reduction and discretization commute. These reduced methods allow the direct simulation of dynamical features such as relative equilibria and relative periodic orbits that can be obscured or difficult to identify in the unreduced dynamics. The methods are demonstrated for the dynamics of an Earth orbiting satellite with a non-spherical J2J_2 correction, as well as the double spherical pendulum. The J2J_2 problem is interesting because in the unreduced picture, geometric phases inherent in the model and those due to numerical discretization can be hard to distinguish, but this issue does not appear in the reduced algorithm, where one can directly observe interesting dynamical structures in the reduced phase space (the cotangent bundle of shape space), in which the geometric phases have been removed. The main feature of the double spherical pendulum example is that it has a nontrivial magnetic term in its reduced symplectic form. Our method is still efficient as it can directly handle the essential non-canonical nature of the symplectic structure. In contrast, a traditional symplectic method for canonical systems could require repeated coordinate changes if one is evoking Darboux' theorem to transform the symplectic structure into canonical form, thereby incurring additional computational cost. Our method allows one to design reduced symplectic integrators in a natural way, despite the noncanonical nature of the symplectic structure.Comment: 24 pages, 7 figures, numerous minor improvements, references added, fixed typo
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