76,160 research outputs found

    Scheduling a future air transport system

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    The scheduling of future timetables is an important driver for aircraft sales and design considerations in future aircraft. Airline companies seek to maximise their profits through capturing passenger demand through the quality of service they offer, within which timetabling plays an important role. In this study a hub and spoke system for medium haul travel is analysed, with particular reference to the time at which departing waves are set from the hub airport. Initially, an optimal wave time based only on the geography of the hub is considered. Subsequently, a model is developed which includes the constraints of market share and limited fleet size, and an example timetable produced. A final note is made about game theoretical aspects that might be considered in moving the work forward

    Surface-renewal models for heat-transfer between walls and fluidized beds

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    Two surface-renewed film penetration models describe transient heat-transfer between a wall and a fluidized bed. Methods are presented for estimation of mean residence times of particles at the transporting surface, their age densities and the average transport coefficients

    Narrative approaches to design multi-screen augmented reality experiences

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    This paper explores how traditional narrative language used in film and theatre can be adapted to create interactivity and a greater sense of presence in the virtual heritage environment. It focuses on the fundamental principles of narrative required to create immersion and presence and investigates methods of embedding intangible social histories into these environments. These issues are explored in a case study of Greens Mill in the 1830’s, interweaving the story of the reform bill riots in Nottingham with the life of George Green, mathematician and proprietor of the Mill

    Narrating the past: virtual environments and narrative

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    This paper explores how traditional narrative language used in film and theatre can be adapted to create interactivity and a greater sense of presence in the virtual heritage environment. It focuses on the fundamental principles of narrative required to create immersion and presence and investigates methods of embedding intangible social histories into these environments. These issues are explored in a case study of Greens Mill in the 1830’s, interweaving the story of the reform bill riots in Nottingham with the life of George Green, mathematician and proprietor of the Mill

    Designing information systems requirements in context: Insights from the theory of deferred action

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    This paper considers conceptual and contextual issues relating to the problem of developing systems models capable of representing knowable and unknowable information requirements. It postulates that the systemic emergence property of systems is the cause of unknowable organisational information requirements. The Theory of Deferred Action and its systems constructs are invoked to explain emergence and how it can be modelled in formal systems. The insights proposed are believed to assist designers in developing functional and relevant approaches within dynamic organisational contexts

    MoM-SO: a Complete Method for Computing the Impedance of Cable Systems Including Skin, Proximity, and Ground Return Effects

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    The availability of accurate and broadband models for underground and submarine cable systems is of paramount importance for the correct prediction of electromagnetic transients in power grids. Recently, we proposed the MoM-SO method for extracting the series impedance of power cables while accounting for skin and proximity effect in the conductors. In this paper, we extend the method to include ground return effects and to handle cables placed inside a tunnel. Numerical tests show that the proposed method is more accurate than widely-used analytic formulas, and is much faster than existing proximity-aware approaches like finite elements. For a three-phase cable system in a tunnel, the proposed method requires only 0.3 seconds of CPU time per frequency point, against the 8.3 minutes taken by finite elements, for a speed up beyond 1000 X.Comment: This paper has now been published in the IEEE Trans. on Power Delivery in Oct. 2015, vol. 30, no. 5, pp. 2110-2118. DOI: 10.1109/TPWRD.2014.237859
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