Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 177 for “"Reference Frame"”.
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Reference Frame Regulation for a Biplanar Bicycle
… of the configuration is that it lacks a stable reference frame from which observations of the surroundings can be based. A solution to this problem is presented here in the form of actuators designed to actively control the oscillations of a reference frame. The orientation of a camera attached …
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Inverter design and analysis using multiple reference frame theory
"Multiple reference frame theory allows for periodically time varying signals to be represented as a set of dc signals. In other words, every periodic signal can be expanded into a Fourier series representation. By modeling an inverter connected to a boost maximum power point tracker (MPPT) in this …
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Reference frame definition, use, and interaction in spatial memory
… among research groups with some concluding reference frames are self-based (egocentric), while others conclude spatial representations are independent from the self (allocentric or intrinsic). This research presents novel methods to assess spatial reference frame use in memory. Chapter 1 …
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Optimal pursuit/evasion spacecraft trajectories in the hill reference frame
… is solved in the Hill-Clohessy-Wiltshire (HCW) reference frame with Earth as the central body and each spacecraft uses continuous low-thrust propulsion. The thrust-pointing direction is the control for each spacecraft. Each vehicle has a finite specific impulse and therefore the mass of each …
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Decentralized power systems : reference-frame theory and stability region generation
… power systems. We expand previous work on reference-frame theory, by providing an alternative interpretation and derivation of the commonly used Park and Clarke transformations. We present a geometric interpretation that has applications in power quality. Secondly, we introduce a framework …
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What spatial reference frame is used for priming in visual search?
… (i.e. relative to other items in the display) frames of reference. However, it is unclear which of these are used in spatial priming. It was found that both allocentric and egocentric cues were used, and that egocentric cues were the most effective for short-term priming (Study A). In exploring …
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A Reference Frame Formulation for the Analysis and Design of Steady Manufacturing Processes
Three example problems are presented to demonstrate the efficiency of the proposed formulations: a laser surface treatment process is analyzed, a drawing process is analyzed and optimized and a multi-pass rolling process is analyzed and designed.
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Three-Dimensional spatial memory graining using virtual reality : effects of reference frame and point-of-view
Humans are usually able to imagine how a terrestrial environment will appear from a new perspective, and usually avoid disorientation because of their ability to transform spatial mental models of their environment. However, astronauts must transform their spatial mental models in three dimensions, …
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Understanding the effect of cognitive reference frames on unmanned aircraft operations
… displays that are often oriented on misaligned reference frames. One example unmanned aircraft mission includes a target described on a north-up reference frame, such as a map. The pilot plans a flight path, to this target, on a north-up map, but controls the aircraft along that flight path …
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New experimental approaches to the population balance equation:Eulerian and Lagrangian viewpoints
… phenotype using either an Eulerian or Lagrangian reference frame. In the Eulerian reference frame one measures the state of an entire cell population at discrete time points. In order to extract the single-cell dynamics from a time series of such measurements it is necessary to solve an inverse …
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NEURAL SIGNALS UNDERLYING COORDINATE FRAME OF ATTENTION IN AREA 7a OF PRIMATE POSTERIOR PARIETAL CORTEX
… signals in world centered coordinates, the reference frame of visual attention was previously unknown. We observed that while some elements of 7a encoding are malleable dependent upon behavioral context, the reference frame of attention is also predominantly encoded in a world-referenced …
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Current Ground Deformation Derived from GPS Observations near PBO Station AC 55 along the Yentna River, South of Denali National Park Reserve, Alaska
… in IGS08. This study then established a local reference frame, which allows for intra-regional deformation analysis on areas of interest located within the local reference frame. From these measurements, a baseline of the relative motion located outside of the landslide body was calculated. The …
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Computational Complexity Optimization on H.264 Scalable/Multiview Video Coding
… in multiple-view video coding. The inter-view reference frames from the adjacent views are exploited for prediction in addition to the temporal prediction. However, due to the increase in the number of reference frames, the computational complexity is also increased. In order to manage the …
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Coordinated Sensor-Based Area Coverage and Cooperative Localization of a Heterogeneous Fleet of Autonomous Surface Vessels (ASVs)
… that the collection operates within a common reference frame. Here we consider the problem of localizing a heterogenous collection of aquatic surface vessels within a global reference frame. We assume that one vessel -- the mother robot -- has access to global position data of high accuracy, …
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Biped robot with a vestibular system
… set variables with respect to a single inertial reference frame. This single reference frame approach has not been used by previous investigators. Control of the joint torques makes biped walking an extraordinary complex problem from a dynamics and control viewpoint. The control scheme that is …
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The development of a dynamically coupled axial-torsional-lateral point transfer matrix for a whirling eccentric mass
… acceleration, acceleration relative to a moving reference frame, Coriolis acceleration and a disguised form of tangential acceleration. The transfer matrix which resulted from this derivation was verified. To verify the lateral motion equations the assumption of a circular whirl orbit in the …
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Design and application of an automated system for camera photogrammetric calibration
… accurately determine vectors in a desired reference frame for any image coordinate, and map points in the reference frame to their corresponding image coordinates. The proposed system is based on a robotic arm which presents an interchangeable light source to the camera in a sequence of …
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Sign-Inverting Vectors Underlie a Coordinate Transformation in the Drosophila Central Brain
… body, limbs, objects or landmarks in a shared reference frame is only now becoming clear.This dissertation focuses on a system of neurons that signals wind direction in the Drosophila central brain. We found that the activity of these neurons, called PFNa, can be thought of as a set of vectors …
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Cognitive requirements for aircraft navigation
… the maintenance of a cognitive link between two reference frames (RFs)--the ego-centered reference frame (ERF) and the world-centered reference frame (WRF). The ERF corresponds to the pilot's forward view of the world and the WRF corresponds to a north-up geographic map. The new map display …
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