613 research outputs found
Analysis of Airspace Traffic Structure and Air Traffic Control Techniques
Air traffic controller cognitive processes are a limiting factor in providing safe
and efficient flow of traffic. Therefore, there has been work in understanding the
factors that drive controllers decision-making processes. Prior work has identified that the airspace structure, defined by the reference elements, procedural elements and pattern elements of the traffic, is important for abstraction and management of the traffic. This work explores in more detail this relationship between airspace structure and air traffic controller management techniques.
This work looks at the current National Airspace System (NAS) and identifies
different types of high altitude sectors, based on metrics that are likely to correlate with
tasks that controllers have to perform. Variations of structural patterns, such as flows and
critical points were also observed. These patterns were then related to groupings by
origins and destinations of the traffic. Deeper pilot-controller voice communication
analysis indicated that groupings by flight plan received consistent and repeatable
sequences of commands, which were identified as techniques. These repeated
modifications generated patterns in the traffic, which were naturally associated with the
standard flight plan groupings and their techniques.
The identified relationship between flight plan groupings and management
techniques helps to validate the grouping structure-base abstraction introduced by Histon
and Hansman (2008). This motivates the adoption of a grouping-focused analysis of
traffic structures on the investigation of how new technologies, procedures and concepts
of operations will impact the way controllers manage the traffic. Consideration of such
mutual effects between structure and controllers' cognitive processes should provide a
better foundation for training and for engineering decisions that include a human-centered
perspective.This work was financially supported by FAA grant 06-G-006 and NASA Cooperative
Agreement NN06CN23A. Anton Koros and Eddie Sierra were the technical sponsors and provided valuable feedback and assistance
Analysis of airspace traffic structure and air traffic control techniques
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2012.Cataloged from PDF version of thesis.Includes bibliographical references (p. 157-163).Air traffic controller cognitive processes are a limiting factor in providing safe and efficient flow of traffic. Therefore, there has been work in understanding the factors that drive controllers decision-making processes. Prior work has identified that the airspace structure, defined by the reference elements, procedural elements and pattern elements of the traffic, is important for abstraction and management of the traffic. This work explores in more detail this relationship between airspace structure and air traffic controller management techniques. This work looks at the current National Airspace System (NAS) and identifies different types of high altitude sectors, based on metrics that are likely to correlate with tasks that controllers have to perform. Variations of structural patterns, such as flows and critical points were also observed. These patterns were then related to groupings by origins and destinations of the traffic. Deeper pilot-controller voice communication analysis indicated that groupings by flight plan received consistent and repeatable sequences of commands, which were identified as techniques. These repeated modifications generated patterns in the traffic, which were naturally associated with the standard flight plan groupings and their techniques. The identified relationship between flight plan groupings and management techniques helps to validate the grouping structure-base abstraction introduced by Histon and Hansman (2008). This motivates the adoption of a grouping-focused analysis of traffic structures on the investigation of how new technologies, procedures and concepts of operations will impact the way controllers manage the traffic. Consideration of such mutual effects between structure and controllers' cognitive processes should provide a better foundation for training and for engineering decisions that include a human-centered perspective.by Emilio Alverne Falcão de Albuquerque Filho.S.M
Third-order nonlinear optical properties of bismuth-borate glasses measured by conventional and thermally managed eclipse Z scan
Third-order nonlinearity one order of magnitude larger than silica is measured in bismuth-borate glasses presenting a fast response (<200 fs). The results for the sign and magnitude of the nonlinearity were obtained using a combination of the eclipse Z scan with thermal nonlinearity managed Z scan, whereas the Kerr shutter technique was employed to obtain the electronic time response of the nonlinearity, all performed with 76 MHz repetition rate 150 fs pulses at 800 nm. Conventional Z scans in the picosecond regime at 532 and 1064 nm were also independently performed, yielding the values of the third-order nonlinear susceptibilities at those wavelengths. The results obtained for the femtosecond response, enhanced third-order nonlinearity of this glass (with respect to silica), place this glass system as an important tool in the development of photonics devices. Electro-optical modulators, optical switches, and frequency converters are some of the applications using second-order nonlinear properties of the Bi-glass based on the rectification model
Identification of Air Traffic Control Sectors with Common Structural Features
In order to identify sectors supporting a minimum differences approach to generic airspace, traffic patterns in 360 high-altitude sectors were examined for common structural features. These structural features are used as the basis for two approaches to classifying current air traffic control sectors into groups which are expected to be similar to each other, and hence a basis for near-term deployment of generic airspace. The first classification approach is a holistic approach, based on emergent sector-wide traffic patterns in order to identify groups of sectors with shared structural features. The second, a decompositional classification approach, proposes using basic structural features (e.g. flows, merges, crosses) as building blocks, and classifies sectors based on combinations of those features. Initial classification results are presented for the holistic approach, and challenges and key steps are presented for the decompositional approach
Analysis Statistics in Practical Problems of Food Health
This study aimed at the application of dietary supplementation in elderly people and, after a period, to prepare a statistical diagnosis of before and after some dimensional information to verify the great influence of diet in these patients. In order to do so, statistical analyzes were used, which are important tools that allow us to perceive the transformations in different chronological periods. As a result, it was possible to verify the history of the patients that were being altered in the last months by the new food supplement implanted, having a statistical explanation besides the nutritional one. However, care has been taken to demonstrate how misunderstanding can hamper interpretation and originate erroneous information from work
Saturation of the Kerr effect in carbon disulfide
Accurate measurements of the nonlinear index in carbon disulfide shows an unusual
saturation law of the Kerr effect which can be used to built a model of light propagation describing the filamentation in this liquid
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