Wright-Patterson Air Force Base

About: Wright-Patterson Air Force Base is a other organization based out in Wright-Patterson AFB, Ohio, United States. It is known for research contribution in the topics: Laser & Microstructure. The organization has 5817 authors who have published 9157 publications receiving 292559 citations. The organization is also known as: Wright-Patterson AFB & FFO.

System identification for adaptive and reconfigurable control

Abstract: In this work, an efficient static system identification method is developed that incorporates prior information. The prior information from flight mechanics enhances the performance of the identification algorithm, yielding more accurate parameter estimates. The proposed static system identification approach is superior to dynamic system identification for on-line identification of rapidly varying plant parameters, making it suitable for adaptive and reconfigurable control. The effectiveness of the static system identification scheme is illustrated in an example problem. A derivative F-16 aircraft control surface (elevator) failure is simulated and the abruptly changing pitch channel control system's stability and control derivatives are successfully identified on-line in the presence of unmodeled dynamics, process noise (clear air turbulence), and realistic measurement noise.

Spin Exchange in Excitons, the Quasicubic Model and Deformation Potentials in II-VI Compounds

Abstract: The effect of the spin-exchange interaction between electron and hole is investigated for the case of excitons originating from one of the $p$-like valence bands and an $s$-like conduction band, as is the case for IIb-VIb compounds. A general exciton matrix is constructed, starting from the work of Pikus. It includes spin-orbit, crystal-field, spin-exchange, and deformation-potential interactions. Use of this matrix then allows a theoretical fit to our experimental data which describes the shift of exciton levels under uniaxial pressure in ZnO, CdS, and CdSe. This fit results in the determination of six deformation potentials, two spin-orbit parameters, the crystal-field parameter, and the exchange parameter. The general theory, when adapted to the zinc-blende structure, allows us to fit our data on cubic ZnS and ZnSe, resulting in a determination of two deformation potentials and the spin-exchange parameter for each compound.