1,721,048 research outputs found
Departure Throughput Study for Boston Logan International Airport
Get PDFWe propose a new parametric representation of the departure capacity of airports. In particular, we show how the departure capacity can be represented by the variation of the average departure throughput as a function of arrivals, conditioned on persistent departure demand. We also show how this approach can be extended to quantify the dependence of departure capacity on other parameters such as the fleet mix. The proposed approaches are illustrated through the parametric estimation of the departure capacity of Boston Logan International Airport (BOS)
Optimization of airport operations at Boston Logan Airport
Get PDFAirport surface congestion results in significant increases in taxi times, fuel burn and emissions at major airports. This thesis proposes a control strategy to improve the performance of airport operations at Boston Logan International Airport. First of all, an Eulerian model of the airport is built in order to be used for the purpose of control. This model can be used with different control strategies, however, in this project a strategy based in Model Predictive Control is chosen, which allows to include some feedback in the decision algorithms. This approach determines which are the optimal moments to release aircraft from the gates (pushback) in order to prevent the airport surface from entering congested states and to reduce the time that flights spend with engines on while taxiing to the runway. Finally, simulations results are shown in order to compare the efficiency of the proposed approach versus the current strategy used in ATC, the well-known First Come, First Served policy. The results demonstrate that lots of benefits are obtained through the proposed method in situations with high demand
Optimization of airport operations at Boston Logan Airport
No full textAirport surface congestion results in significant increases in taxi times, fuel burn and emissions at major airports. This thesis proposes a control strategy to improve the performance of airport operations at Boston Logan International Airport. First of all, an Eulerian model of the airport is built in order to be used for the purpose of control. This model can be used with different control strategies, however, in this project a strategy based in Model Predictive Control is chosen, which allows to include some feedback in the decision algorithms. This approach determines which are the optimal moments to release aircraft from the gates (pushback) in order to prevent the airport surface from entering congested states and to reduce the time that flights spend with engines on while taxiing to the runway. Finally, simulations results are shown in order to compare the efficiency of the proposed approach versus the current strategy used in ATC, the well-known First Come, First Served policy. The results demonstrate that lots of benefits are obtained through the proposed method in situations with high demand
Optimization of airport operations at Boston Logan Airport
No full textAirport surface congestion results in significant increases in taxi times, fuel burn and emissions at major airports. This thesis proposes a control strategy to improve the performance of airport operations at Boston Logan International Airport. First of all, an Eulerian model of the airport is built in order to be used for the purpose of control. This model can be used with different control strategies, however, in this project a strategy based in Model Predictive Control is chosen, which allows to include some feedback in the decision algorithms. This approach determines which are the optimal moments to release aircraft from the gates (pushback) in order to prevent the airport surface from entering congested states and to reduce the time that flights spend with engines on while taxiing to the runway. Finally, simulations results are shown in order to compare the efficiency of the proposed approach versus the current strategy used in ATC, the well-known First Come, First Served policy. The results demonstrate that lots of benefits are obtained through the proposed method in situations with high demand
Observation and Analysis of Departure Planning Operations at Boston Logan International Airport
No full textThe Departure Planner (DP) is a concept for a decision-aiding tool that is aimed at improving the departure operations performance at major congested airports. In order to support the development of the DP tool, the flow constraints and their causalities in the departure process – primarily responsible for generating inefficiencies and delays- need to be identified. This thesis is and effort to identify such flow constraints and gain a deep understanding of the underlying dynamics of the departure process based on field observations and data analysis at Boston Logan International Airport. It was observed that the departure process is a complex interactive queuing system, where aircraft queues from as a manifestation of the flow constraints. While departure delays were observed in all airport components (runways, taxiways, ramps and gates), it was concluded that the flow constraints manifest mainly at he runway system, which exhibits the largest delays and queues…National Aeronautics and Space Administration Ames Research Cente
Departure operations at Boston Logan International Airport
Get PDFThesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2001.Includes bibliographical references (p. 199-203).In order to support the development of improved methods for departure operations, the flow constraints and their causalities --primarily responsible for inefficiencies and delays-- need to be identified. This thesis is an effort to identify such flow constraints and gain a deep understanding of the departure process underlying dynamics based on field observations and analysis conducted at Boston Logan International Airport. It was observed that the departure process forms a complex interactive queuing system and is highly controlled by the air traffic controllers. Therefore, Flow constraints were identified with airport resources (runways, taxiways, ramp and gates) and with air traffic controllers due to their workload and control strategies. While departure delays were observed in all airport components, flow constraints manifested mainly at the runway system, where the longest delays and queues concentrated. Major delays and inefficiencies were also observed due to flow constraints at National Air Space locations downstream of the airport, which propagate back and block the departure flow from the airport. The air traffic controllers' main strategies in managing the traffic and dealing with the flow constraints were also identified.(cont.) Based on these observations, a core departure process abstraction was posed consisting of a queuing element (representing the delays) and a control element (representing the air traffic controller actions). The control element represents blocking the aircraft flow, to maintain safe airport operation according to Air Traffic Control procedures and to regulate the outbound flow to constrained downstream resources. Based on this physical abstraction, an analytical queuing framework was developed and used to analyze the departure process dynamics under three different scenarios: the overall process between pushback and takeoff, departure sub-processes between controller/pilot communication events and under downstream restrictions. Passing which results mainly from aircraft sequencing and their suspension under special circumstances (such as downstream restrictions) was used as a manifestation of the control behavior. It was observed that Logan Airport exhibits high uncertainty and limited sequencing, hindering the air traffic controllers' ability to efficiently manage the traffic and comply with restrictions. In conclusion, implications for improved methods for departure operations are inferred from the observations and analysis.by Husni Rifat Idris.Ph.D
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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