2,769 research outputs found
Capabilities of operational infrared sounding systems from satellite altitude
Initial attempts at using satellite radiances resulted in the production of temperature profiles similar to those produced by radiosondes. While increases in accuracy were made and additional increases are expected to result from increased instrument capabilities, it was recognized that the production of level temperatures is not consistent with the average temperature that is represented by the radiances
Planform effects on the supersonic aerodynamics of multibody configurations
An experimental and theoretical investigation of the effect of planform on the supersonic aerodynamics of low-fineness-ratio multibody configurations was conducted. Longitudinal and lateral-directional aerodynamic and flow visualization data were obtained on three multibody configurations. The data indicated that planform has a small effect on the zero lift drag of a multibody configuration. The longitudinal data obtained at lifting conditions showed a sensitivity to planform shape. Lateral-directional data obtained for all configurations did not uncover any unusual stability traits for this class of configuration. A comparison study was also made between the planform effects observed on single-body and multibody configurations. Results from this study indicate that the multibody concept appears to offer a mechanism for employing a low-sweep wing with no significant increase in zero-lift drag but still retaining high-performance characteristics at high-lift conditions. Evaluation of the linear-theory prediction methods revealed a general inability of the methods to predict the characteristics of low-fineness-ratio geometries
Fiscal Shocks, the Trade Balance, and the Exchange Rate
This paper investigates empirically, using a VAR model, the response of the exchange rate and the trade balance to fiscal policy shocks for the U.S. economy during the period 1981:3-2005:3. The results indicate that positive shocks to real government purchases generate a persistent increase in the budget deficit, a transitory expansionary effect on output, and a long-lived positive effect on the price level, but reduce the real interest rate. Simultaneously, and consistent with interest parity, the real exchange rate depreciates, and the trade balance improves. Negative shocks to net taxes also generate a persistent increase in the budget deficit, and the effects on the model variables are generally in the same direction, but are almost never significant. Our results indicate it is inappropriate to attribute rising trade balance deficits to expansionary fiscal policy shocks, even though these shocks generate long-lived increases in the budget deficit.
Inflation Forecast Targeting: A VAR Approach
We show how to implement inflation forecast targeting using a VAR model and derive the implied inflation-output variability frontier. Our approach is based on dynamic, stochastic simulations of the average inflation rate over a two-year horizon using the moving average representation of the VAR model. Using real time data over two samples, we estimate the inflation-output variability frontier for the U.S. and show that it has shifted favorably over time. We consider the frequency and nature of the policy interventions required to achieve target inflation in both samples and compare these interventions over time.
Personal Computing for the Visually Impaired
The problem of providing feedback from the computer to a visually impaired user is examined. The use of traditional tactile input and output (Braille) is described. The limitations of voice output are discussed, and difficulties posed by complicated screen formats and screen review are considered
Estimating the Inflation-Output Variability Frontier with Inflation Targeting: A VAR Approach
This paper (i) illustrates how a VAR model can be used to evaluate inflation targeting, (ii) derives the policy frontier available to the central bank using counterfactual experiments with real time data, and (iii) estimates how this frontier has changed over time in terms of the position and slope of the available tradeoff between output gap variability and inflation variability under inflation targeting. Various inflation targets are considered as are tolerance bands of varying width around these targets. The results indicate that over time (i) a given reduction in inflation variability is associated with a smaller rise in output variability and that (ii) a given inflation variability is achieved with smaller interest rate volatility. Consistent with the data, our results require federal funds rate persistence, though no instrument instability was observed.
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