185,117 research outputs found

    SimInf: An R package for Data-driven Stochastic Disease Spread Simulations

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    We present the R package SimInf which provides an efficient and very flexible framework to conduct data-driven epidemiological modeling in realistic large scale disease spread simulations. The framework integrates infection dynamics in subpopulations as continuous-time Markov chains using the Gillespie stochastic simulation algorithm and incorporates available data such as births, deaths and movements as scheduled events at predefined time-points. Using C code for the numerical solvers and OpenMP to divide work over multiple processors ensures high performance when simulating a sample outcome. One of our design goal was to make SimInf extendable and enable usage of the numerical solvers from other R extension packages in order to facilitate complex epidemiological research. In this paper, we provide a technical description of the framework and demonstrate its use on some basic examples. We also discuss how to specify and extend the framework with user-defined models.Comment: The manual has been updated to the latest version of SimInf (v6.0.0). 41 pages, 16 figure

    Data-driven modeling of systemic delay propagation under severe meteorological conditions

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    The upsetting consequences of weather conditions are well known to any person involved in air transportation. Still the quantification of how these disturbances affect delay propagation and the effectiveness of managers and pilots interventions to prevent possible large-scale system failures needs further attention. In this work, we employ an agent-based data-driven model developed using real flight performance registers for the entire US airport network and focus on the events occurring on October 27 2010 in the United States. A major storm complex that was later called the 2010 Superstorm took place that day. Our model correctly reproduces the evolution of the delay-spreading dynamics. By considering different intervention measures, we can even improve the model predictions getting closer to the real delay data. Our model can thus be of help to managers as a tool to assess different intervention measures in order to diminish the impact of disruptive conditions in the air transport system.Comment: 9 pages, 5 figures. Tenth USA/Europe Air Traffic Management Research and Development Seminar (ATM2013

    Virtual Integration Platforms (VIP) –A Concept for Integrated and Interdisciplinary Air Transportation Research and Assessment

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    The paper descibes a new methodology for a holistic development of air transportation concepts. The Virtual Integration Plattform (VIP) concept is based on an IT tool chain as well as human collaborative methods to deal with complex systems. As a result the definitions of future air transportation concepts for short range "Quiet and Clean", long range "Comfortable and Clean" and individual transport "Fast and Flexible" are presente

    Principles in Patterns (PiP) : Evaluation of Impact on Business Processes

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    The innovation and development work conducted under the auspices of the Principles in Patterns (PiP) project is intended to explore and develop new technology-supported approaches to curriculum design, approval and review. An integral component of this innovation is the use of business process analysis and process change techniques - and their instantiation within the C-CAP system (Class and Course Approval Pilot) - in order to improve the efficacy of curriculum approval processes. Improvements to approval process responsiveness and overall process efficacy can assist institutions in better reviewing or updating curriculum designs to enhance pedagogy. Such improvements also assume a greater significance in a globalised HE environment, in which institutions must adapt or create curricula quickly in order to better reflect rapidly changing academic contexts, as well as better responding to the demands of employment marketplaces and the expectations of professional bodies. This is increasingly an issue for disciplines within the sciences and engineering, where new skills or knowledge need to be rapidly embedded in curricula as a response to emerging technological or environmental developments. All of the aforementioned must also be achieved while simultaneously maintaining high standards of academic quality, thus adding a further layer of complexity to the way in which HE institutions engage in "responsive curriculum design" and approval. This strand of the PiP evaluation therefore entails an analysis of the business process techniques used by PiP, their efficacy, and the impact of process changes on the curriculum approval process, as instantiated by C-CAP. More generally the evaluation is a contribution towards a wider understanding of technology-supported process improvement initiatives within curriculum approval and their potential to render such processes more transparent, efficient and effective. Partly owing to limitations in the data required to facilitate comparative analyses, this evaluation adopts a mixed approach, making use of qualitative and quantitative methods as well as theoretical techniques. These approaches combined enable a comparative evaluation of the curriculum approval process under the "new state" (i.e. using C-CAP) and under the "previous state". This report summarises the methodology used to enable comparative evaluation and presents an analysis and discussion of the results. As the report will explain, the impact of C-CAP and its ability to support improvements in process and document management has resulted in the resolution of numerous process failings. C-CAP has also demonstrated potential for improvements in approval process cycle time, process reliability, process visibility, process automation, process parallelism and a reduction in transition delays within the approval process, thus contributing to considerable process efficiencies; although it is acknowledged that enhancements and redesign may be required to take advantage of C-CAP's potential. Other aspects pertaining to C-CAP's impact on process change, improvements to document management and the curation of curriculum designs will also be discussed
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