2,906 research outputs found
Maximum Entropy/Optimal Projection (MEOP) control design synthesis: Optimal quantification of the major design tradeoffs
The underlying philosophy and motivation of the optimal projection/maximum entropy (OP/ME) stochastic modeling and reduced control design methodology for high order systems with parameter uncertainties are discussed. The OP/ME design equations for reduced-order dynamic compensation including the effect of parameter uncertainties are reviewed. The application of the methodology to several Large Space Structures (LSS) problems of representative complexity is illustrated
Tail States in a Superconductor with Magnetic Impurities
A field theoretic approach is developed to investigate the profile and
spectrum of sub-gap states in a superconductor subject to a weak magnetic
impurity potential. Such states are found to be associated with inhomogeneous
supersymmetry broken instanton configurations of the action.Comment: 4 pages, 2 eps figure
On neural networks in identification and control of dynamic systems
This paper presents a discussion of the applicability of neural networks in the identification and control of dynamic systems. Emphasis is placed on the understanding of how the neural networks handle linear systems and how the new approach is related to conventional system identification and control methods. Extensions of the approach to nonlinear systems are then made. The paper explains the fundamental concepts of neural networks in their simplest terms. Among the topics discussed are feed forward and recurrent networks in relation to the standard state-space and observer models, linear and nonlinear auto-regressive models, linear, predictors, one-step ahead control, and model reference adaptive control for linear and nonlinear systems. Numerical examples are presented to illustrate the application of these important concepts
Tourist perceptions of Dubai and Expo2020
In 2020, Dubai will host the World Expo. Not only will the Expo 2020 draw an expected 25 million tourists, but since the announcement, it has been a focal point for progressing towards the lofty goals of the Dubai tourism vision, mobilizing people, companies, projects, and the entire country towards 2020. This particular mega-event is a crucial component of the wider branding strategy. Expo2020 has also played a significant role in the marketing communications and branding of Dubai since its announcement through multiple communication channels. The purpose of this paper is to explore tourists’ perceptions of Dubai and Expo 2020 and to understand tourists’ attitudes and perceived value of different information sources and marketing channels. In doing so, this paper will provide some initial insights into understanding tourists' perceptions and attitudes towards Dubai in relation to Expo2020
Interferometric imaging concepts with reduced formation-keeping constraints
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/77370/1/AIAA-2001-4610-885.pd
Connectionist algorithms for identification and control - System structure and convergence analysis
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/77285/1/AIAA-1997-686-380.pd
Design and implementation of robust decentralized control laws for the ACES structure at Marshall Space Flight Center
Many large space system concepts will require active vibration control to satisfy critical performance requirements such as line-of-sight accuracy. In order for these concepts to become operational it is imperative that the benefits of active vibration control be practically demonstrated in ground based experiments. The results of the experiment successfully demonstrate active vibration control for a flexible structure. The testbed is the Active Control Technique Evaluation for Spacecraft (ACES) structure at NASA Marshall Space Flight Center. The ACES structure is dynamically traceable to future space systems and especially allows the study of line-of-sight control issues
Observations of deep coral and sponge assemblages in Olympic Coast National Marine Sanctuary, Washington. Cruise Report: NOAA Ship McArthur II Cruise AR06-07/07
From May 22 to June 4, 2006, NOAA scientists led a research cruise using the ROPOS Remotely Operated Vehicle (ROV) to conduct a series of dives at targeted sites in the
Olympic Coast National Marine Sanctuary (OCNMS) with the goal of documenting deep coral and sponge communities. Dive sites were selected from areas for which OCNMS had side scan sonar data indicating the presence of hard or complex substrate. The team completed 11 dives in sanctuary waters ranging from six to 52 hours in length, at depths ranging from 100 to 650 meters. Transect surveys were completed at 15 pre-selected sites, with additional observations made at five other sites. The survey locations included sites both inside and outside the Essential Fish Habitat (EFH) Conservation Area, known as Olympic 2, established by the Pacific Fishery Management Council, enacted on June 12, 2006. Bottom trawling is prohibited in the Olympic 2 Conservation Area for nontribal fishermen. The Conservation Area covers 159.4 square nautical miles or about 15
percent of the sanctuary. Several species of corals and sponges were documented at 14 of the 15 sites surveyed, at sites both inside and outside the Conservation Area, including numerous gorgonians and the stony corals Lophelia pertusa and Desmophyllum dianthus, as well as small patches of the reef building sponge Farrea occa. The team also
documented Lophelia sp. and Desmophyllum sp. coral rubble, dead gorgonians, lost fishing gear, and other anthropogenic debris, supporting concerns over potential risks of
environmental disturbances to coral health. (PDF contains 60 pages.
Distributed parameter modelling of flexible spacecraft: Where's the beef?
This presentation discusses various misgivings concerning the directions and productivity of Distributed Parameter System (DPS) theory as applied to spacecraft vibration control. We try to show the need for greater cross-fertilization between DPS theorists and spacecraft control designers. We recommend a shift in research directions toward exploration of asymptotic frequency response characteristics of critical importance to control designers
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