13,511 research outputs found

    Characteristic distribution of finite-time Lyapunov exponents for chimera states

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    It is shown that probability densities of finite-time Lyapunov exponents, corresponding to chimera states, have a characteristic shape. Such distributions could be used as a signature of chimera states, particularly in systems for which the phases of all the oscillators cannot be measured directly. In such cases, the characteristic distribution may be obtained indirectly, via embedding techniques, thus making it possible to detect chimera states in systems where they could otherwise exist, unnoticed

    Harm: The counterfactual comparative account, the omission and pre-emption problems, and well-being

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    The concept of “harm” is ubiquitous in moral theorising, and yet remains poorly defined. Bradley suggests that the counterfactual comparative account of harm is the most plausible account currently available, but also argues that it is fatally flawed, since it falters on the omission and pre-emption problems. Hanna attempts to defend the counterfactual comparative account of harm against both problems. In this paper, I argue that Hanna’s defence fails. I also show how his defence highlights the fact that both the omission and the pre-emption problems have the same root cause – the inability of the counterfactual comparative account of harm to allow for our implicit considerations regarding well-being when assessing harm. While its purported neutrality with regard to substantive theories of well-being is one of the reasons that this account is considered to be the most plausible on offer, I will argue that this neutrality is illusory

    The Nature of Context-Sensitive Solutions, Stakeholder Involvement and Critical Issues in the Urban Context

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    Over the last several decades many transportation and planning agencies have experienced conflicting demands emerging from the need to develop projects in an expeditious manner while at the same time involving stakeholders in the decision-making process, which sometimes is perceived as slowing project delivery and/or increasing costs. Given this tension between apparently conflicting demands, it is important to understand how the stakeholder involvement is being carried out and what best practices may be recommended. This study examines the issue in the context of a relatively new policy framework – Context Sensitive Solutions (CSS) – which supports the early integration of stakeholders into the planning process. The report pays particular attention to stakeholders’ involvement in projects within urban centers, where there is likely to be more complexity, both in terms of the number of stakeholders and end users affected. CSS is a relatively new process and not consistently interpreted or applied across states and/or agencies. The literature suggests that an underlying assumption when applying CSS principles to community involvement processes is that stakeholders are empowered through clear policies and procedures directed towards their participation. In our research, we found that the extent to which public agencies apply the CSS framework and involve and respond to stakeholders depends on each agency\u27s interest to engage the public in the deliberation process to find the best-fit project for a community. It is likely that the increased integration of stakeholders into the planning and project development process will not become a state of practice until the benefits flowing from community involvement are clearly understood by the agency staff. The CSS literature describes many benefits associated with comprehensive stakeholder engagement, including gaining constituents\u27 buy-in and support for project financing. A movement toward standardizing CSS policies and directives across the country will facilitate a public discussion about the benefits of engaging communities into the project design phase and away from solely expert-based designs. In addition, there are a number of stakeholder involvement practices that, if adopted, could expedite the integration of communities\u27 views and values in the decision-making process, while at the same time minimizing the chances of protracted consultation processes, time delays and additional costs

    Optimized shooting method for finding periodic orbits of nonlinear dynamical systems

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    An alternative numerical method is developed to find stable and unstable periodic orbits of nonlinear dynamical systems. The method exploits the high-efficiency of the Levenberg-Marquardt algorithm for medium-sized problems and has the additional advantage of being relatively simple to implement. It is also applicable to both autonomous and non-autonomous systems. As an example of its use, it is employed to find periodic orbits in the R\"ossler system, a coupled R\"ossler system, as well as an eight-dimensional model of a flexible rotor-bearing; problems which have been treated previously via two related methods. The results agree with the previous methods and are seen to be more accurate in some cases. A simple implementation of the method, written in the Python programming language, is provided as an Appendix.Comment: 21 pages, 7 figure

    Compositional Morphology for Word Representations and Language Modelling

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    This paper presents a scalable method for integrating compositional morphological representations into a vector-based probabilistic language model. Our approach is evaluated in the context of log-bilinear language models, rendered suitably efficient for implementation inside a machine translation decoder by factoring the vocabulary. We perform both intrinsic and extrinsic evaluations, presenting results on a range of languages which demonstrate that our model learns morphological representations that both perform well on word similarity tasks and lead to substantial reductions in perplexity. When used for translation into morphologically rich languages with large vocabularies, our models obtain improvements of up to 1.2 BLEU points relative to a baseline system using back-off n-gram models.Comment: Proceedings of the 31st International Conference on Machine Learning (ICML

    A new family of solutions of the force-free field equation

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    A new family of solutions has been found for force-free magnetic fields and Beltrami flows, which admits a complete classification in terms of the eigenvalues of the problem. In the absence of boundary values to determine them uniquely, the eigenvalues correspond to the entire set of real numbers, except for zero. The eigenvalues are degenerate in that each eigenvalue has many eigensolutions associated with it. For each eigensolution we have been able to identify sets of equilibrium or null points and lines. The linear mappings of these null points and lines are all unstable. Finally, we derive the first integral of energy associated with this family of solutions

    Extreme ultraviolet emission lines of Ni xii in laboratory and solar spectra

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    A linear force-free field solution is presented in cylindrical coordinates, formulated in terms of trigonometric and Bessel functions. A numerical exploration has revealed that this solution describes magnetic field lines that meander in Cartesian space, as well as field lines that lie on toroidal flux surfaces. These tori are in (or close to) the plane perpendicular to the cylindrical axis. Nested tori, as well as tori with shells that have finite thickness, were found. The parameter space of the solution shows that the tori exist within a bounded range of values

    The Level of Information Systems Integration in Romania

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    Integration is an activity that unites people, equipments, programs but also managerial practices and helps a company to put its knowledge into good use. In Romania, more and more private companies choose to have integrated systems to help them grow. Public owned companies and institutions, for example The National House of Pensions and Other Social Insurance Right, invested large amounts of founds in the development of new information systems to help them gather, process and disseminate data from the population.integration, information systems, standards, data integration, application integration

    An assessment of five different theoretical frameworks to study the uptake of innovations

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    There are several theoretical frameworks one can draw upon to study the adoption process. Extension Theory, Bounded Rationality, Diffusion Theory, the Theory of Reasoned Action and Consumer Behaviour Theory were of particular interest to us. In assessing the frameworks we looked for contradictions, and how and whether these frameworks could be used to study the adoption process. The assessment was done by using our own conceptual framework of the adoption process and we discuss the results in this paper. We found that the different frameworks don‘t contradict each other and when combined into our conceptual framework they offer very useful constructs for studying the adoption process.adoption, innovations, theory, Agricultural and Food Policy, Environmental Economics and Policy, Research Methods/ Statistical Methods, Resource /Energy Economics and Policy,
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