23,939 research outputs found

    Effective statistical physics of Anosov systems

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    We present evidence indicating that Anosov systems can be endowed with a unique physically reasonable effective temperature. Results for the two paradigmatic Anosov systems (i.e., the cat map and the geodesic flow on a surface of constant negative curvature) are used to justify a proposal for extending Ruelle's thermodynamical formalism into a comprehensive theory of statistical physics for nonequilibrium steady states satisfying the Gallavotti-Cohen chaotic hypothesis.Comment: 38 pages, 17 figures. Substantially more details in sections 4 and 6; new and revised figures also added. Typos and minor errors (esp. in section 6) corrected along with minor notational changes. MATLAB code for calculations in section 16 also included as inline comment in TeX source now. The thrust of the paper is unaffecte

    A Thick Industrial Design Studio Curriculum

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    This presentation was part of the session : Pedagogy: Procedures, Scaffolds, Strategies, Tactics24th National Conference on the Beginning Design StudentThis paper describes an industrial design studio course based in a private university in Izmir, Turkey where second year industrial design students, for the first time, engage in a studio project. The design studio course emphasises three distinct areas of competence in designing that are the focus of the curriculum. They are; design process: the intellectual act of solving a design problem; design concept: the imagination and sensibility to conceive of appropriate design ideas; and presentation: the ability to clearly and evocatively communicate design concepts. The studio is 'thick' with materials, tasks and activities that are intentionally sequenced to optimise learning in a process that is known as educational 'scaffolding.' The idea of a process--a patient journey toward it's destination, is implicit in the studio that is full of opportunities for reflection-in-action. A significant feature is the importance placed on drawing and model making. An exemplary design process should show evidence of 'breadth'--meaning a wide search for solutions where a range of alternatives explored throughout; followed by an incremental refinement of the chosen solution where elements of the final design concept are developed thoroughly and in detail--called 'depth.' Learning to design is predicated on an engagement in and manipulation of the elements of the design problem. Evidence of that learning will be found by examining the physical materials and results of the design process. The assessment criteria are published with the brief at the outset of design project and outcomes are spelt out at the end. Students are remind throughout project of the criteria, which is to say they are reminded of pedagogical aims of the studio. Assessment criteria are detailed and the advantages of summative assessment are described

    Abstract Hidden Markov Models: a monadic account of quantitative information flow

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    Hidden Markov Models, HMM's, are mathematical models of Markov processes with state that is hidden, but from which information can leak. They are typically represented as 3-way joint-probability distributions. We use HMM's as denotations of probabilistic hidden-state sequential programs: for that, we recast them as `abstract' HMM's, computations in the Giry monad D\mathbb{D}, and we equip them with a partial order of increasing security. However to encode the monadic type with hiding over some state X\mathcal{X} we use DX→D2X\mathbb{D}\mathcal{X}\to \mathbb{D}^2\mathcal{X} rather than the conventional X→DX\mathcal{X}{\to}\mathbb{D}\mathcal{X} that suffices for Markov models whose state is not hidden. We illustrate the DX→D2X\mathbb{D}\mathcal{X}\to \mathbb{D}^2\mathcal{X} construction with a small Haskell prototype. We then present uncertainty measures as a generalisation of the extant diversity of probabilistic entropies, with characteristic analytic properties for them, and show how the new entropies interact with the order of increasing security. Furthermore, we give a `backwards' uncertainty-transformer semantics for HMM's that is dual to the `forwards' abstract HMM's - it is an analogue of the duality between forwards, relational semantics and backwards, predicate-transformer semantics for imperative programs with demonic choice. Finally, we argue that, from this new denotational-semantic viewpoint, one can see that the Dalenius desideratum for statistical databases is actually an issue in compositionality. We propose a means for taking it into account
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