1,407 research outputs found

    Integrating management tools and concepts to develop an estuarine planning support system: A case study of the Humber Estuary, Eastern England

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    © 2015. Estuaries are important because of their multiple uses and users which often makes them challenging to manage since management must strike a balance between the needs of users, the estuaries' ecological and economic value and the context of multiple legislative drivers. To facilitate management we have therefore developed an Estuarine Planning Support System (EPSS) framework using the Humber Estuary, Eastern England, as a case study which integrates the current legislation tools and concepts. This integrated EPSS framework is an improvement on previous approaches for assessing cumulative impacts as it takes into account legislative drivers, management tools and other mechanisms for controlling plans/projects specific to the estuary. It therefore enables managers and users to assess and address both the current state and the way in which a new industrial, port or urban development could impact an estuary in an accessible and understandable framework

    Sequential predictors under time-varying feedback and measurement delays and sampling

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    We build sequential predictors for time-varying linear systems with time-varying input delays, outputs, sampling in the control, and time-varying measurement delays. We prove global exponential stability and robustness properties. We allow the sup norm of the input delay to be arbitrarily large and aperiodic sampling. We use a new set of dynamical extensions that contain output measurements, and whose advantages over existing methods include their lack of distributed terms

    Viscous vortex flows

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    Several computational studies are currently being pursued that focus on various aspects of representing the entire lifetime of the viscous trailing vortex wakes generated by an aircraft. The formulation and subsequent near-wing development of the leading-edge vortices formed by a delta wing are being calculated at modest Reynolds numbers using a three-dimensional, time-dependent Navier-Stokes code. Another computational code was developed to focus on the roll-up, trajectory, and mutual interaction of trailing vortices further downstream from the wing using a two-dimensional, time-dependent, Navier-Stokes algorithm. To investigate the effect of a cross-wind ground shear flow on the drift and decay of the far-field trailing vortices, a code was developed that employs Euler equations along with matched asymptotic solutions for the decaying vortex filaments. And finally, to simulate the conditions far down stream after the onset of the Crow instability in the vortex wake, a full three-dimensional, time-dependent Navier-Stokes code was developed to study the behavior of interacting vortex rings

    A Study of Executable Model Based Systems Engineering from DODAF Using Simulink

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    Diagrams and visuals often cannot adequately capture a complex system’s architecture for analysis. The Department of Defense Architectural Framework (DoDAF), written to follow the Unified Modeling Language (UML), is a collection of mandated common architectural products for interoperability among the DoD components. In this study, DoDAF products from as-is Remotely Piloted Aircraft (RPA) Satellite Communication (SATCOM) systems have been utilized for the creation of executable architectures as part of an Executable Model Based Systems Engineering (EMBSE) process. EMBSE was achieved using Simulink, a software tool for modeling, simulating and analyzing dynamic systems. This study has demonstrated that DoDAF products can be created and executed following the rules of UML for analysis. It has also shown that DoDAF products can be utilized to build analysis models. Furthermore, these analysis models and executable architectures have been presented to a panel of experts on the topic. The comments and study results show a desire for executable architectures as well as their viability as presented in Simulink. This study concludes there is a need, a use and a method to implement objective analysis using EMBSE from DoDAF products in Simulink for current and future DoD systems

    MicroRNAs sound off

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    The message is loud and clear. MicroRNA-96, one in a cluster of three related neurosensory microRNAs, is crucial to the development and maintenance of inner ear hair cells and hearing in mice and humans. Two recent studies show that mutations in the critical seed region of the microRNA underlie the cause of hair cell degeneration and progressive hearing loss. Other recent reports reveal the general requirement of microRNAs for sensory epithelial development and maintenance in Dicer knockout mouse ear. The challenge begins to determine whether microRNAs will resonate as therapeutic agents or target molecules to preserve or restore hearing
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