7,159 research outputs found
A flight investigation of simulated data-link communications during single-pilot IFR flight. Volume 2: Flight evaluations
Key problems in single pilot instrument flight operations are in the management of flight data and the processing of cockpit information during conditions of heavy workload. A flight data console was developed to allow simulation of a digital data link to replace the current voice communications stem used in air traffic control. This is a human factors evaluation of a data link communications system to determine how such a system might reduce cockpit workload, improve flight proficiency, and be accepted by general aviation pilots. The need for a voice channel as backup to a digital link is examined. The evaluations cover both airport terminal area operations and full mission instrument flight. Results show that general aviation pilots operate well with a digital data link communications system. The findings indicate that a data link system for pilot/ATC communications, with a backup voice channel, is well accepted by general aviation pilots and is considered to be safer, more efficient, and result in less workload than the current voice system
A flight investigation of simulated data link communications during single-pilot IFR flight
A Flight Data Console (FDC) was developed to allow simulation of a digital communications link to replace the current voice communication system used in air traffic control (ATC). The voice system requires manipulation of radio equipment, read-back of clearances, and mental storage of critical information items, all contributing to high workload, particularly during single-pilot operations. This was an inflight study to determine how a digital communications system might reduce cockpit workload, improve flight proficiency, and be accepted by general aviation pilots. Results show that instrument flight, including approach and landing, can be accomplished quite effectively using a digital data link system for ATC communications. All pilots expressed a need for a back-up voice channel. When included, this channel was used sparingly and principally to confirm any item of information about which there might be uncertainty
A flight investigation of simulated data-link communications during single-pilot IFR flight. Volume 1: Experimental design and initial test
A Flight Data Console simulation of a digital communication link to replace the current voice communication system used in air traffic control (ATC) was developed. The study determined how a digital communications system reduces cockpit workload, improve, flight proficiency, and is acceptable to general aviation pilots. It is shown that instrument flight, including approach and landing, can be accomplished by using a digital data link system for ATC communication
Developing and applying an integrated modular design methodology within a SME
Modularity within a product can bring advantages to the design process by facilitating enhanced design reuse, reduced lead times, decreased cost and higher levels of quality. While the benefits of modularity are becoming increasingly better known, at present it is usually left to the designers themselves to introduce modularity into products. Studies into modularity have shown that byimplementing 'formal' methods, further benefits can be made in terms of time, cost, quality and performance. Current approaches that have been proposed for the formal development of modular design methodologies fail to accurately represent knowledge that is inherently produced during design projects and fail to consider design from the different viewpoints of the development process. This work, built on previous work on modularity and design for reuse, aims to develop an integrated design methodology that will optimise the modules created through the design process and allow for modularity to be 'built-in' to product development from the initial stages. The methodology andassociated tools have been developed to provide an easy-to-use approach to modularity that has support for design rationales and company knowledge that aid in effective design decision making. The methodology, named GeMoCURE, provides an integrated total solution to modular design based on reuse of proven physical and knowledge modules. Its incremental nature allows for the optimalstructure to be maintained as the design progresses. A special focus has been on the application of this approach for Small to Medium Enterprises (SMEs), which are typically challenged by a lack of design human resources and expertise
Application of remote sensing to state and regional problems
The methods and procedures used, accomplishments, current status, and future plans are discussed for each of the following applications of LANDSAT in Mississippi: (1) land use planning in Lowndes County; (2) strip mine inventory and reclamation; (3) white-tailed deer habitat evaluation; (4) remote sensing data analysis support systems; (5) discrimination of unique forest habitats in potential lignite areas; (6) changes in gravel operations; and (7) determining freshwater wetlands for inventory and monitoring. The documentation of all existing software and the integration of the image analysis and data base software into a single package are now considered very high priority items
Dark-ages Reionization & Galaxy Formation Simulation VIII. Suppressed growth of dark matter halos during the Epoch of Reionization
We investigate how the hydrostatic suppression of baryonic accretion affects
the growth rate of dark matter halos during the Epoch of Reionization. By
comparing halo properties in a simplistic hydrodynamic simulation in which gas
only cools adiabatically, with its collisionless equivalent, we find that halo
growth is slowed as hydrostatic forces prevent gas from collapsing. In our
simulations, at the high redshifts relevant for reionization (between
and ), halos that host dwarf galaxies () can be reduced by up to a factor of 2 in mass due to the
hydrostatic pressure of baryons. Consequently, the inclusion of baryonic
effects reduces the amplitude of the low mass tail of the halo mass function by
factors of 2 to 4. In addition, we find that the fraction of baryons in dark
matter halos hosting dwarf galaxies at high redshift never exceeds
of the cosmic baryon fraction. When implementing baryonic processes, including
cooling, star formation, supernova feedback and reionization, the suppression
effects become more significant with further reductions of to
60\%. Although convergence tests suggest that the suppression may become weaker
in higher resolution simulations, this suppressed growth will be important for
semi-analytic models of galaxy formation, in which the halo mass inherited from
an underlying N-body simulation directly determines galaxy properties. Based on
the adiabatic simulation, we provide tables to account for these effects in
N-body simulations, and present a modification of the halo mass function along
with explanatory analytic calculations.Comment: 17 pages, 11 figures; Updated to match the published version. Two
changes in Figures 1 and 3 in order to 1) correct bin sizes of the 10^8 and
10^8.5 Msol bins for NOSN_NOZCOOL_NoRe (was 0.5, should be 0.25); 2) include
stellar mass in baryon fraction (was missed in Fig. 3). Quantitative
description of Fig. 3 changed slightly in Section 2.2. All other results and
conclusions remain unchange
Dark-ages reionization and galaxy formation simulation--VII. The sizes of high-redshift galaxies
We investigate high-redshift galaxy sizes using a semi-analytic model
constructed for the Dark-ages Reionization And Galaxy-formation Observables
from Numerical Simulation project. Our fiducial model, including strong
feedback from supernovae and photoionization background, accurately reproduces
the evolution of the stellar mass function and UV luminosity function. Using
this model, we study the size--luminosity relation of galaxies and find that
the effective radius scales with UV luminosity as at --. We show that recently discovered very luminous
galaxies at (Bowler et al. 2016) and (Oesch et al. 2016)
lie on our predicted size--luminosity relations. We find that a significant
fraction of galaxies at will not be resolved by JWST, but GMT will have
the ability to resolve all galaxies in haloes above the atomic cooling limit.
We show that our fiducial model successfully reproduces the redshift evolution
of average galaxy sizes at . We also explore galaxy sizes in models
without supernova feedback. The no-supernova feedback models produce galaxy
sizes that are smaller than observations. We therefore confirm that supernova
feedback plays an important role in determining the size--luminosity relation
of galaxies and its redshift evolution during reionization.Comment: 10 pages, 4 figures, Accepted for publication in MNRA
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