147 research outputs found
A framework for the classification and prioritization of arrival and departure routes in Multi-Airport Systems Terminal Manoeuvring Areas
© 2015 American Institute of Aeronautics and Astronautics Inc, AIAA. All right reserved.Typically major cities (London, New York, Tokyo) are served by several airports effectively creating a Multi-Airport System or Metroplex. The operations of the Metroplex airports are highly dependent on one another, which renders their efficient management difficult. This paper proposes a framework for the prioritization of arrival and departure routes in Multi-Airport Systems Terminal Manoeuvring Areas. The framework consists of three components. The first component presents a new procedure for clustering arrival and departure flights into dynamic routes based on their temporal and spatial distributions through the identification of the important traffic flow patterns throughout the day of operations. The second component is a novel Analytic Hierarchy Process model for the prioritization of the dynamic routes, accounting for a set of quantitative and qualitative characteristics important for Multi-Airport Systems operations. The third component is a priority-based model for the facility location of the optimal terminal waypoints (fixes), which accounts for the derived priorities of each dynamic route, while meeting the required separation distances. The proposed Analytic Hierarchy Process model characteristics are validated by subject matter experts. The developed framework is applied to the London Metroplex case study
Nature documentaries as catalysts for change: Mapping out the 'Blackfish Effect'
It is essential for us to understand what drives human behaviour if we want to tackle anthropogenic damage to the environment. Popular media can play an important role in shaping public attitudes, behaviours and norms towards wildlife, and documentaries in particular have become an increasingly prominent tool for social change. There is, however, a need for robust impact evaluation both in documentary-making and in conservation, to refine future interventions. The 2013 documentary Blackfish portrayed human–orca interactions at the US-based marine park, SeaWorld. Following its release, SeaWorld suffered financial difficulties and the company underwent structural changes, including a cessation of its orca breeding programme. These impacts have often been attributed to the Blackfish documentary, but little evidence has been provided to justify these claims. We combined an analysis of stock market data and semi-structured interviews with 26 key informants to build an in-depth contribution analysis. We used General Elimination Methodology, a qualitative impact evaluation methodology to build an understanding of the impact of Blackfish. We found a consensus among stakeholder groups that Blackfish induced negative publicity for SeaWorld and a change in people's perceptions of captivity. As a result, attendance at the park decreased and the market value of the company dropped. Blackfish catalysed a whole movement against marine mammal captivity. There were three key factors that led to its impact: the support from major distribution channels which allowed it to reach major audiences, emotional impact of the content and timing of its release. Blackfish benefitted from a perfect storm, building upon decades of activism to create an appropriate cultural climate for its release in 2013
Ev\u27rybody loves to dance
https://digitalcommons.usf.edu/aa_sheet_music/1011/thumbnail.jp
Modelling persistence and intermittency in air pollution
This paper describes a fractional autoregressive model and a co-integration model for the prediction of maximum daily ozone concentration at Lidcombe The models accommodate long-range dependence (LRD) and second-order intermittency of the data. It is found that ozone and wind speed are co- integrated, and the resulting fractional co-integration model gives a much improved performance on predicting ozone episodes than the univariate model, which relies on the history of the daily ozone series alone. 1 Introduction An air quality management scheme requires a thorough understanding of the trends in monitoring dat..
Column-Test Data Analyses and Geochemical Modeling to Determine Uranium Reactive Transport Parameters at a Former Uranium Mill Site (Grand Junction, Colorado)
The long-term release of uranium from residual sources at former uranium mill sites was often not considered in prior conceptual and numerical models, as contaminant removal focused on meeting radiological standards. To determine the reactive transport parameters, column tests were completed with various influent waters (deionized water, site groundwater, and local river water) on sediment from identified areas with elevated uranium on the solid phase in (1) vadose-zone (VZ) sediments, (2) saturated-zone sediments with higher organic carbon content, and (3) both vadose- and saturated-zone sediments with additional gypsum content. The gypsum was precipitated when low-pH, high-sulfate, tailings fluids or acidic waste disposal water were buffered by natural aquifer calcite dissolution. In general, the resulting uranium release was higher in the sediments with greater uranium concentrations. However, the addition of deionized water (DI) to the VZ sediments delayed the uranium release until higher-alkalinity groundwater was added. Higher-alkalinity river water continued to remove uranium from the VZ sediments for an extended number of pore volumes, with the uranium being above typical standards. Thus, river flooding is more efficient at removing uranium from VZ sediments than precipitation events (DI water in column tests). Organic carbon provides a stronger uranium sorption surface, which can be explained with geochemical modeling or a larger constant sorption coefficient (Kd). Without organic carbon, the typical sorption in sands and gravels is easily measurable, but sorption is stronger at lower, water-phase uranium concentrations. This effect can be simulated with geochemical modeling, but not with a constant Kd. Areas with gypsum create situations in which geochemical sorption is more difficult to simulate, which is likely due to the presence of uranium within mineral coatings. All the above mechanisms for uranium release must be considered when evaluating remedial strategies. Column testing provides initial input parameters that can be used in future reactive transport modeling to evaluate long-term uranium release rates and concentrations
Herding in Aid Allocation
Although there exists a vast literature on aid efficiency (the effect of aid on GDP), and that aid allocation determinants have been estimated, little is known about the minute details of aid allocation. This article investigates empirically a claim repeatedly made in the past that aid donors herd. Building upon a methodology applied to financial markets, this article finds that aid donors herd similarly to portfolio funds on financial markets. It also estimates the causes of herding and finds that political transitions towards more autocratic regimes repel donors, but that transitions towards democracy have no effect. Finally, identified causes of herding explain little of its overall level, suggesting strategic motives play an important role
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