The Rebound Effect in the Aviation Sector

The rebound effect, i.e., the (partial) offset of the energy efficiency improvement potential due to a reduction in marginal usage costs and the associated increase in consumer demand, has been extensively studied for residential energy demand and automobile travel. This study presents a quantitative estimate of the rebound effect for an air traffic network including the 22 busiest airports, which serve 14 of the highest O-D cities within the domestic U.S. aviation sector. To satisfy this objective, passenger flows, aircraft operations, flight delays and the resulting energy use are simulated. Our model results indicate that the average rebound effect in this network is about 19%, for the range of aircraft fuel burn reductions considered. This is the net impact of an increase in air transportation supply to satisfy the rising passenger demand, airline operational effects that further increase supply, and the mitigating effects of an increase in flight delays. Although the magnitude of the rebound effect is small, it can be significant for a sector that has comparatively few options for reducing greenhouse gas emissions

Planning fuel-conservative descents in an airline environmental using a small programmable calculator: Algorithm development and flight test results

A simple, airborne, flight-management descent algorithm was developed and programmed into a small programmable calculator. The algorithm may be operated in either a time mode or speed mode. The time mode was designed to aid the pilot in planning and executing a fuel-conservative descent to arrive at a metering fix at a time designated by the air traffic control system. The speed model was designed for planning fuel-conservative descents when time is not a consideration. The descent path for both modes was calculated for a constant with considerations given for the descent Mach/airspeed schedule, gross weight, wind, wind gradient, and nonstandard temperature effects. Flight tests, using the algorithm on the programmable calculator, showed that the open-loop guidance could be useful to airline flight crews for planning and executing fuel-conservative descents

Development of an annoyance model based upon elementary auditory sensations for steady-state aircraft interior noise containing tonal components

The purpose of this investigation was to develop a noise annoyance model, superior to those already in use, for evaluating passenger response to sounds containing tonal components which may be heard within current and future commercial aircraft. The sound spectra investigated ranged from those being experienced by passengers on board turbofan powered aircraft now in service to those cabin noise spectra passengers may experience within advanced propeller-driven aircraft of the future. A total of 240 sounds were tested in this experiment. Sixty-six of these 240 sounds were steady state, while the other 174 varied temporally due to tonal beating. Here, the entire experiment is described, but the analysis is limited to those responses elicited by the 66 steady-state sounds

State-Uncertainty preferences and the Risk Premium in the Exchange rate market

This paper introduces state-uncertainty preferences into the Lucas (1982) economy, showing that this type of preferences helps to explain the exchange rate risk premium. Under these preferences we can distinguish between two factors driving the exchange rate risk premium: “macroeconomic risk” and “the risk associated with variation in the private agents’ perception on the level of uncertainty”. State-uncertainty preferences amount to assuming that a given level of consumption will yield a higher level of utility the lower is the level of uncertainty perceived by consumers. Furthermore, empirical evidence from three main European economies in the transition period to the euro provides empirical support for the modelRisk premium, taste shocks, fundamental uncertainty.

Design of a Pressure Transient Campaign for a Giant Middle Eastern Field

Imperial Users onl

Near real-time stereo vision system

The apparatus for a near real-time stereo vision system for use with a robotic vehicle is described. The system is comprised of two cameras mounted on three-axis rotation platforms, image-processing boards, a CPU, and specialized stereo vision algorithms. Bandpass-filtered image pyramids are computed, stereo matching is performed by least-squares correlation, and confidence ranges are estimated by means of Bayes' theorem. In particular, Laplacian image pyramids are built and disparity maps are produced from the 60 x 64 level of the pyramids at rates of up to 2 seconds per image pair. The first autonomous cross-country robotic traverses (of up to 100 meters) have been achieved using the stereo vision system of the present invention with all computing done onboard the vehicle. The overall approach disclosed herein provides a unifying paradigm for practical domain-independent stereo ranging

Market Dynamics in Edgeworth Exchange

Edgeworth exchange is the fundamental general equilibrium model, yet equilibrium predications and theories of price adjustment for this model remain untested. This paper reports an experimental test of Edgeworth exchange which demonstrates that prices and allocations converge sharply to the competitive equilibrium. Price convergence is evaluated with the tatonnement model, interpreted as a disequilibrium model of across- period price adjustment. Subsequently, the extent of within-period adjustment is compared to that of across-period adjustment. Since most observed price adjustment occurs within trading periods, price adjustment data is evaluated with two disequilibrium models of within- period trades. These models are the Geometric Mean model, which is formulated in this paper, and the Hahn process (Hahn and Negishi [1962]). Price dynamics from experiment sessions fit the Geometric Mean model better than the Hahn process, and in addition, the Geometric Mean model provides direction for development of an Edgeworth exchange bargaining model.Competitive equilibrium, disequilibrium dynamics, double auction, Edgeworth exchange, experimental economics, exchange economy, Hahn process, market dynamics

Some t-tests for N-of-1 trials with serial correlation

N-of-1 trials allow inference between two treatments given to a single individual. Most often, clinical investigators analyze an individual's N-of-1 trial data with usual t-tests or simple nonparametric methods. These simple methods do not account for serial correlation in repeated observations coming from the individual. Existing methods accounting for serial correlation require simulation, multiple N-of-1 trials, or both. Here, we develop t-tests that account for serial correlation in a single individual. The development includes effect size and precision calculations, both of which are useful for study planning. We then evaluate and compare their Type I and II errors and interval estimators to those of usual t-tests analogues via Monte Carlo simulation. The serial t-tests clearly outperform the usual t-tests commonly used in reporting N-of-1 results. Examples from N-of-1 clinical trials in fibromyalgia patients and from a behavioral health setting exhibit how accounting for serial correlation can change inferences. These t-tests are easily implemented and more appropriate than simple methods commonly used; however, caution is needed when analyzing only a few observations. Keywords: Autocorrelation; Cross-over studies; Repeated measures analysis; Single-case experimental design; Time-seriesComment: 23 pages, 6 figures, 6 table