20,855 research outputs found

    Making Mountains out of Molehills: Challenges for Implementation of Cross-Disciplinary Research in the Big Data Era

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    We present a “Researcher’s Hierarchy of Needs” (loosely based on Maslow’s Hierarchy of Needs) in the context of interdisciplinary research in a “big data” era. We discuss multiple tensions and difficulties that researchers face in today’s environment, some current efforts and suggested policy changes to address these shortcomings and present our vision of a future interdisciplinary ecosystem

    Jaynes' Maximum Entropy Principle, Riemannian Metrics and Generalised Least Action Bound

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    The set of solutions inferred by the generic maximum entropy (MaxEnt) or maximum relative entropy (MaxREnt) principles of Jaynes - considered as a function of the moment constraints or their conjugate Lagrangian multipliers - is endowed with a Riemannian geometric description, based on the second differential tensor of the entropy or its Legendre transform (negative Massieu function). The analysis provides a generalised {\it least action bound} applicable to all Jaynesian systems, which provides a lower bound to the cost (in generic entropy units) of a transition between inferred positions along a specified path, at specified rates of change of the control parameters. The analysis therefore extends the concepts of "finite time thermodynamics" to the generic Jaynes domain, providing a link between purely static (stationary) inferred positions of a system, and dynamic transitions between these positions (as a function of time or some other coordinate). If the path is unspecified, the analysis gives an absolute lower bound for the cost of the transition, corresponding to the geodesic of the Riemannian hypersurface. The analysis is applied to (i) an equilibrium thermodynamic system subject to mean internal energy and volume constraints, and (ii) a flow system at steady state, subject to constraints on the mean heat, mass and momentum fluxes and chemical reaction rates. The first example recovers the {\it minimum entropy cost} of a transition between equilibrium positions, a widely used result of finite-time thermodynamics. The second example leads to a new {\it minimum entropy production principle}, for the cost of a transition between steady state positions of a flow system.Comment: 19 pages; 1 figure; corrected for sign of metric, Jan 2011; ISBN: 978-981-4277-31-

    Back to the Future – the Marginal Utility of History in Economics

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    Economics and economic history share many fundamental research problems and have a rich shared intellectual history. Still, works by economic historians are rarely read or referenced in economics. In this essay we attempt to identify the cost of this negligence. In particular, we argue that a restrictive understanding of the economic research programme excludes available evidence and precludes analysis of complex situational constraints on economic decision-making.

    Optimal finite-time processes in stochastic thermodynamics

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    For a small system like a colloidal particle or a single biomolecule embedded in a heat bath, the optimal protocol of an external control parameter minimizes the mean work required to drive the system from one given equilibrium state to another in a finite time. In general, this optimal protocol obeys an integro-differential equation. Explicite solutions both for a moving laser trap and a time-dependent strength of such a trap show finite jumps of the optimal protocol to be typical both at the beginning and the end of the process.Comment: 4 pages, 1 figure, accepted for publication in Phys. Rev. Let
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