The Other Campus

unpublishe

Evaluation of display and control concepts for a terminal configured vehicle in final approach in a windshear environment

A revised treatment of nonrandom inputs was incorporated in the model. Response behavior was observed for two display configurations (a pictorial EADI presentation and a flight-director configuration requiring use of a panel-mounted airspeed indicator), two control configurations (attitude and velocity control wheel steering), and two shear environments, each of which contained a head-to-tail shear and a vertical component. In general, performance trends predicted by the model were confirmed experimentally. Experimental and analytical results both indicated superiority to the EADI display with respect to regulation of height and airspeed errors. Velocity steering allowed tighter regulation of height errors, but control parameters had little influence on airspeed regulation. Model analysis indicated that display-related differences could be ascribed to differences in the quality of speed-related information provided by the two displays

Some computational techniques for estimating human operator describing functions

Computational procedures for improving the reliability of human operator describing functions are described. Special attention is given to the estimation of standard errors associated with mean operator gain and phase shift as computed from an ensemble of experimental trials. This analysis pertains to experiments using sum-of-sines forcing functions. Both open-loop and closed-loop measurement environments are considered

Seasonal bias in household vulnerability to poverty stimates: insights from a natural experiment

Using data from 260 households from the Hadejia-Nguru wetlands, the paper shows that vulnerability to poverty estimates are biased if the data used is seasonal. The seasonal bias in the consumption expenditure is less pronounced than in its variance. The paper further shows that the relative sizes of the seasonal bias in expected consumption expenditure and its variance determines the final magnitude of the bias. However, the bias in the expected consumption expenditure is sufficiently corrected by including seasonal dummy variables. We therefore encourage researchers to consider seasonality when they are modelling consumption expenditure with the aim of estimating vulnerability.Seasonal bias; vulnerability to poverty; natural experiment; Nigeria

Use of Linear Perspective Scene Cues in a Simulated Height Regulation Task

As part of a long-term effort to quantify the effects of visual scene cuing and non-visual motion cuing in flight simulators, an experimental study of the pilot's use of linear perspective cues in a simulated height-regulation task was conducted. Six test subjects performed a fixed-base tracking task with a visual display consisting of a simulated horizon and a perspective view of a straight, infinitely-long roadway of constant width. Experimental parameters were (1) the central angle formed by the roadway perspective and (2) the display gain. The subject controlled only the pitch/height axis; airspeed, bank angle, and lateral track were fixed in the simulation. The average RMS height error score for the least effective display configuration was about 25% greater than the score for the most effective configuration. Overall, larger and more highly significant effects were observed for the pitch and control scores. Model analysis was performed with the optimal control pilot model to characterize the pilot's use of visual scene cues, with the goal of obtaining a consistent set of independent model parameters to account for display effects

Child labour and poverty linkages: A micro analysis from rural Malawian data

This study assesses the impact of income and asset poverty on child work using the rural sub-sample of the 2004 Malawi Integrated Household Survey. Instrumenting consumption expenditure with a location dummy variable and interacting consumption expenditure with household land-holding size in probit models, the likelihood of child labour is found to relate negatively with household consumption. On the other hand child labour relates positively with household land-holding size for consumption poor households only and when labour markets are imperfect. These findings do not discourage asset accumulation policies as a remedy against child labour but support policies that aim at increasing returns on the assets.Child labour, Poverty, Assets, Malawi

Dynamics of the Kuiper Belt

Our current knowledge of the dynamical structure of the Kuiper Belt is reviewed here. Numerical results on long term orbital evolution and dynamical mechanisms underlying the transport of objects out of the Kuiper Belt are discussed. Scenarios about the origin of the highly non-uniform orbital distribution of Kuiper Belt objects are described, as well as the constraints these provide on the formation and long term dynamical evolution of the outer Solar system. Possible mechanisms include an early history of orbital migration of the outer planets, a mass loss phase in the outer Solar system and scattering by large planetesimals. The origin and dynamics of the scattered component of the Kuiper Belt is discussed. Inferences about the primordial mass distribution in the trans-Neptune region are reviewed. Outstanding questions about Kuiper Belt dynamics are listed.Comment: 22 pages plus 8 figures added footnote, figure

Use of the tilt cue in a simulated heading tracking task

The task was performed with subjects using visual-only cues and combined visual and roll-axis motion cues. Half of the experimental trials were conducted with the simulator rotating about the horizontal axis; to suppress the tilt cue, the remaining trials were conducted with the simulator cab tilted 90 deg so that roll-axis motions were about earth vertical. The presence of the tilt cue allowed a substantial and statistically significant reduction in performance scores. When the tilt cue was suppressed, the availability of motion cues did not result in significant performance improvement. These effects were accounted for by the optimal-control pilot/vehicle model, wherein the presence or absence of various motion cues was represented by appropriate definition of the perceptual quantities assumed to be used by the human operator