Sequential Monte Carlo simulation of collision risk in free flight air traffic

Within HYBRIDGE a novel approach in speeding up Monte Carlo simulation of rare events has been developed. In the current report this method is extended for application to simulating collisions with a stochastic dynamical model of an air traffic operational concept. Subsequently this extended Monte Carlo simulation approach is applied to a simulation model of an advanced free flight operational concept; i.e. one in which aircraft are responsible for self separation with each other. The Monte Carlo simulation results obtained for this advanced concept show that the novel method works well, and that it allows studying rare events that stayed invisible in previous Monte Carlo simulations of advanced air traffic operational concepts

Land-Use Transport Interaction: State of the Art

This paper investigates innovative approaches to the integration of land-use and transport planning in urban regions. Engineering, economic and social-science based theories and empirical studies are analyzed regarding their ability to explain the interaction between land use and transport - that land use determines traffic flows and that transport infrastructure changes land-use patterns. In addition, this paper provides an overview of the state of the art of computer models for the simulation of land use and transport. Based on these theories and models the effectiveness of policies to influence land use and transport in urban regions is assessed.Urban location theory, transportation research, land use- transport interaction, urban simulation modeling, location choice

3D-in-2D Displays for ATC.

This paper reports on the efforts and accomplishments of the 3D-in-2D Displays for ATC project at the end of Year 1. We describe the invention of 10 novel 3D/2D visualisations that were mostly implemented in the Augmented Reality ARToolkit. These prototype implementations of visualisation and interaction elements can be viewed on the accompanying video. We have identified six candidate design concepts which we will further research and develop. These designs correspond with the early feasibility studies stage of maturity as defined by the NASA Technology Readiness Level framework. We developed the Combination Display Framework from a review of the literature, and used it for analysing display designs in terms of display technique used and how they are combined. The insights we gained from this framework then guided our inventions and the human-centered innovation process we use to iteratively invent. Our designs are based on an understanding of user work practices. We also developed a simple ATC simulator that we used for rapid experimentation and evaluation of design ideas. We expect that if this project continues, the effort in Year 2 and 3 will be focus on maturing the concepts and employment in a operational laboratory settings

Land-Use Transport Interaction

This report is a part of the results of the EU project TRANSLAND (see Berichte aus dem Institut für Raumplanung 47). The project investigated innovative approaches to the integration of land-use and transport planning in urban regions. The report presents engineering, economic and social-science based theories and empirical studies to explain the interaction between land use and transport - that land use determines traffic flows and that transport infrastructure changes land-use patterns. In addition the report provides an overview of the state of the art of computer models for the simulation of land use and transport. Based on these theories and models the effectiveness of policies to influence land use and transport in urban regions is assessed

On the underlying dynamics of traffic conflicts related to stochastic behaviour

The aim of this paper is to analyse why and how air traffic conflicts occur as a result of the stochastic behaviour of both the ownship and the intruder and to show how system-level characteristics can be derived from such an analysis. Ensemble dynamics in a given traffic scenario have already been analysed using multi-agent simulations by many; however, such an analysis is hardly ever backed up and interpreted in terms of an analytical study. By making use of directional conflict probability maps, characteristics of integral, system-level quantities can be explained, providing further insight into the relationship of speed distribution parameters and system performance quantities, namely, safety and throughput

A quantitative framework to assess pilot workload during applications of airborne separation assistance

One of the principal concerns with the introduction of Airborne Separation Assistance System (ASAS) Work Package 1 is the operational flexibility of delegating to pilots responsibility for maintaining separation as in keeping with applications of Limited, Extended and Full Delegation [183]. This operational flexibility, among other things, includes identification of potential problems, generation of solutions to resolve them, and implementation and monitoring of the chosen solution. It has also been predicted that this will introduce new performance issues and present implications that will reflect significant changes in the way pilots and air traffic controllers will perform their respective tasks [4], [174], [175], [176] and [177]. As human performance considerations are expected to be central to the performance of advanced cockpit and Air Traffic Management (ATM) system [11] there is the need to address concerns which arise [11] pertaining to the possibility of adverse changes, impact and implementation on the cognitive and behaviour processes of pilots and air traffic controllers. Against this background, the work in this thesis presents the development of an eighty- five factor task index and self-assessment performance framework for the determination of cognitive and performance challenges of pilots during applications of Limited, Extended and Full Delegation of Airborne Separation Assistance. The quantitative framework is developed using the technique of Critical Task Analysis (CTA) and is based on tasks which are inherent to dynamic situations during each respective application. The performance framework was then incorporated into an existing decision support tool, Multi-criteria Analysis for Concept Evaluation (MACE) [9] whose operating and performance utilities were extensively expanded and modified from forty factors to eighty five factors to present the novel approach of this thesis. This novel approach is the development of another decision support tool, Multi-criteria Analysis for Pilot Evaluation, (MpE). The objectives of MpE are: 1. To obtain quantitative measures of the workload of pilots during the ASAS applications already identified. 2. To clearly delineate the functions of pilot from those of ATC during the respective applications. 3. To predict the effects of change in the tasks environment on the workload of both human operators, pilots and controllers. To illustrate the functionality and capabilities of MpE two thousand hypothetical ASAS applications conducted by pilots were simulated. No statistical methods were employed for arriving at this number of 2000, however it was deemed that the number adequately covered the various combinations of the scenarios within the ASAS applications. To achieve objective three above, three hundred and fifty hypothetical ASAS applications conducted by air traffic controllers were simulations using the programme in its original form of (MACE). Whereas Situation Awareness may not be deemed as an ASAS application it was however included as an ASAS application during both simulations to provide insight into the cognitive processes involved in dimension of regulation and to confirm whether CDTI would enable a better representation of the traffic situation. In this thesis workload is defined as a comparison between Heaven and Hell where the closer to Heaven the workload is seen as easier and the closer to Hell the more difficult. To arrive at the workload measurements for pilots during each respective application the eighty-five factors served as indicators. Then, using a specific value scale provided by the programme these indicators were related to one or several Criteria, (a list provided by the programme expressing human dimensions) through linear regression. A quadratic solution where a positive result indicates the strength of the influence {Heaven) and a negative the weakness of the influence {Hell) provides the final outcome. Of the 2000 ASAS application simulations conducted for pilots, the overall regression coefficient p, (where p indicates the effect of change) derived from the coefficient 05 produced a value of p = 0.956. As this value is nearer to 1 it indicates a positive representation of the distance to Heaven, where the closer to Heaven the workload is seen as easier. Accordingly, from this result one can deduce that the work of pilots during the four ASAS applications will be easier

Safety‐oriented discrete event model for airport A‐SMGCS reliability assessment

A detailed analysis of State of the Art Technologies and Procedures into Airport Advanced-Surface Movement Guidance and Control Systems has been provided in this thesis, together with the review ofStatistical Monte Carlo Analysis, Reliability Assessment and Petri Nets theories. This practical and theoretical background has lead the author to the conclusion that there is a lack of linkage in between these fields. At the same of time the rapid increasing of Air Traffic all over the world, has brought in evidence the urgent need of practical instruments able to identify and quantify the risks connected with Aircraft operations on the ground, since the Airport has shown to be the actual ‘bottle neck’ of the entire Air Transport System. Therefore, the only winning approach to such a critical matter has to be multi-disciplinary, sewing together apparently different subjects, coming from the most disparate areas of interest and trying to fulfil the gap. The result of this thesis work has come to a start towards the end, when a Timed Coloured Petri Net (TCPN) model of a ‘sample’ Airport A-SMGCS has been developed, that is capable of taking into account different orders of questions arisen during these recent years and tries to give them some good answers. The A-SMGCS Airport model is, in the end, a parametric tool relying on Discrete Event System theory, able to perform a Reliability Analysis of the system itself, that: • uses a Monte Carlo Analysis applied to a Timed Coloured Petri Net, whose purpose is to evaluate the Safety Level of Surface Movements along an Airport • lets the user to analyse the impact of Procedures and Reliability Indexes of Systems such as Surface Movement Radars, Automatic Dependent Surveillance-Broadcast, Airport Lighting Systems, Microwave Sensors, and so on… onto the Safety Level of Airport Aircraft Transport System • not only is a valid instrument in the Design Phase, but it is useful also into the Certifying Activities an in monitoring the Safety Level of the above mentioned System with respect to changes to Technologies and different Procedures.This TCPN model has been verified against qualitative engineering expectations by using simulation experiments and occupancy time schedules generated a priori. Simulation times are good, and since the model has been written into Simulink/Stateflow programming language, it can be compiled to run real-time in C language (Real-time workshop and Stateflow Coder), thus relying on portable code, able to run virtually on any platform, giving even better performances in terms of execution time. One of the most interesting applications of this work is the estimate, for an Airport, of the kind of A-SMGCS level of implementation needed (Technical/Economical convenience evaluation). As a matter of fact, starting from the Traffic Volume and choosing the kind of Ground Equipment to be installed, one can make predictions about the Safety Level of the System: if the value is compliant with the TLS required by ICAO, the A-SMGCS level of Implementation is sufficiently adequate. Nevertheless, even if the Level of Safety has been satisfied, some delays due to reduced or simplified performances (even if Safety is compliant) of some of the equipment (e.g. with reference to False Alarm Rates) can lead to previously unexpected economical consequences, thus requiring more accurate systems to be installed, in order to meet also Airport economical constraints. Work in progress includes the analysis of the effect of weather conditions and re-sequencing of a given schedule. The effect of re-sequencing a given schedule is not yet enough realistic since the model does not apply inter arrival and departure separations. However, the model might show some effect on different sequences based on runway occupancy times. A further developed model containing wake turbulence separation conditions would be more sensitive for this case. Hence, further work will be directed towards: • The development of On-Line Re-Scheduling based on the available actual runway/taxiway configuration and weather conditions. • The Engineering Safety Assessment of some small Italian Airport A-SMGCSs (Model validation with real data). • The application of Stochastic Differential Equations systems in order to evaluate the collision risk on the ground inside the Place alone on the Petri Net, in the event of a Short Term Conflict Alert (STCA), by adopting Reich Collision Risk Model. • Optimal Air Traffic Control Algorithms Synthesis (Adaptive look-ahead Optimization), by Dynamically Timed Coloured Petri Nets, together with the implementation of Error-Recovery Strategies and Diagnosis Functions

Modelling the environmental justice of the spatial distribution of air quality

PhD ThesisRelationships between air pollution, health and deprivation potentially result in the highest cost to both the public and the government in terms of increased mortality and morbidity; hence establishing links between them is important and justifiable. The concept of Environmental Justice (EJ) questions whether certain socio-economic groups bear a disproportionate burden of environmental externalities, and whether policy and practice are equitable and fair. This research presents an innovative air quality modelling framework to map the EJ of the spatial distribution of air quality; and the impact of air quality management measures on existing EJ concerns. To assist in this goal, a modelling approached has been developed which enables the assessment of traffic management solutions that may create only subtle changes in the traffic flow regimes; and accurately assesses the impact of a reduction in vehicle kilometres travelled (VKT). Strong evidence of environmental injustice in the current distribution and production of poor air quality has been provided in the literature. However, the overwhelming majority of existing studies have concentrated on the analysis of current or historic associations. As a result their methodologies do not allow for the analysis of future strategies therefore, a gap exists in understanding the EJ implications of air quality strategies or schemes designed to improve air quality. Recent years have seen heightened political focus on policy and attempts to improve air quality. Whilst it is broadly suggested in the literature that improving air quality also will improve existing EJ concerns, evidence to date shows that even in situations where air quality is improving, the rate of concentration improvement is lowest for the poor. This research presents a suite of linked models of traffic, emission, dispersion, and geodemographic models (the modelling framework) that together allow not only more accurate assessment of the existing EJ situation to be established over using traditional techniques, but also the assessment of future air quality strategies and schemes designed to improve air quality which may improve or exacerbate the existing EJ relationship. ii The use of microsimulation traffic modelling in conjunction with an instantaneous emissions model (IEM) is a well-established emissions modelling technique. However, the use of IEMs is generally confined to exploration of emissions outputs and not the subsequent dispersion of emissions in order to determine air quality. This research successfully combines advanced microscale modelling techniques and applies them in the context of an EJ study in order to produce an original modelling framework capable of household level EJ analysis. This research has established that, at a city level, there is no linear relationship between air quality and deprivation in the North East cities of Durham, Newcastle and Gateshead. However, analysis of geodemographic data at the household and postcode levels has provided evidence of environmental injustice in air quality across all three study areas. Additionally, this research has explored the impact of reductions in VKT as a proposed air quality management measure. Thereby, the reductions required in VKT (over 2010 traffic flows) in one study area, Durham, have been established in order to meet both EU air quality limits and future carbon targets. Incremented 5% VKT reduction changes were made to the base-case 2010 scenario until all considered targets were met. Based on a 2010 vehicle fleet, a 50% reduction in traffic through Durham’s AQMA is required to meet all EU air quality targets. Similarly, a 25% reduction in VKT is required assuming a 2020 vehicle fleet, and by 2025 a 15% reduction in VKT would ensure Durham met its air quality targets. Moreover, a 10% reduction in VKT by 2020, and 25% reduction by 2025 would ensure carbon dioxide (CO2) reductions across the study area equal to those set out in the carbon budget. Furthermore, it has been established that the reductions in VKT to meet both EU air quality limits and future carbon targets eliminates the identified EJ issue in Durham. Moreover, if future VKT is constrained to 2010 levels, the spatial distribution of air quality will be environmentally just in both the 2020 and 2025 assessment yearsEngineering and Physical Sciences Research Council (EPSRC) for funding this work. Also, thanks are given to Durham County Council for additional funding