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 20 for “"Spatial modulation"”.
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Spatial modulation in the underwater acoustic communication channel
A modulation technique for increasing the reliable data rate achievable by an underwater acoustic communication system is presented and demonstrated. The technique, termed spatial modulation, seeks to control the spatial distribution of signal energy such that multiple parallel communication …
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Performance investigation of spatial modulation systems under realistic channel models
… In recent years, a new MIMO technology named the spatial modulation (SM) has attracted signi cant research interest due to its reported enhancement on the system performance with the reasonable system complexity. Before a new technology comes into real use, it is necessary to comprehensively …
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Spatial Modulation of Light Using Surface Waves in a Fabry-Perot Interferometer
Made available in DSpace on 2014-12-08T22:24:49Z (GMT). No. of bitstreams: 1 7020983.pdf: 2239558 bytes, checksum: 16ecbdc1c8e9805737c0059beb7da0fb (MD5) Previous issue date: 1970
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Optical communication through the turbulent atmosphere with transmitter and receiver diversity, wavefront control, and coherent detection
… We analyze several different optical field spatial modulation techniques, each of which is based on a different assumption about the quality of turbulence state information at the transmitter. For example, we explore a diversity optical system with perfect turbulence state information at the …
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Phase derivative microscopy of biological cells and tissues
… of transparent specimens. These methods utilize spatial light modulation at the Fourier plane of a bright field microscope to optically obtain the derivatives of the phase and increase the contrast of the final image. The controllable spatial modulation pattern allows obtaining both the …
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A holographic system that records front-surface detail of a scene moving at high velocity
… during the exposure of a hologram results in a spatial modulation of the recorded fringe contrast. On reconstruction this produces a spatial amplitude modulation of the reconstructed wavefront that tends to blur out the image. This paper discusses a novel holographic technique that uses an …
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Novel DMD-based Lidar and Display Systems
… illumination to project a binary spatially-modulated DMD to a distant plane. Rather, this dissertation investigates four optical architectures, two for lidar applications and two for display applications, that deviate from the prescribed design forms. First, an imaging lidar system …
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The effect of the Nintendo Wii Fit on the balance control and gross motor function of children with spastic hemiplegic cerebral palsy
… as well as problems with the temporal and spatial modulation of appropriate muscle action in response to balance perturbations. Children with hemiplegia have also been shown to develop direction-specific postural control at a slower pace than typically developing children. Apart from their …
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Measurement of the spin diffusion rate of dipolar order in single crystal calcium fluoride
… diffusion in magnetic resonance is to encode a spatial modulation of magnetization in a sample and then measure it's attenuation over time. The difficulty in measuring spin diffusion in solid crystals by these scattering methods is that the spin diffusion rate is very slow (of order 1 x 10⁻¹² …
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Design of a dynamic calibration phantom to be used to calculate the temporal resolution of a tomographic imaging device
… imaging device exists. Analogous to the spatial modulation transfer function used for characterizing spatial resolution, the concept of temporal Modulation Transfer Function (t-MTF) can be used to enable characterization of temporal resolution. A scanner's t-MTF represents the percent …
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Embodied Representation of Time in Virtual Reality
… their capacity to encode temporal change as a spatial or perceptual phenomenon. In reality, human experience of time is embodied and dynamic, perceived through interaction and memory. Existing digital systems fail to capture this dimension, reducing time to a passive parameter. This thesis …
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Second-order nonlinear optical interactions and cascading effects in thinorganic films
… work, for the first time is proposed the use of spatial modulation of nonlinear properties of waveguide according Fibonacci law. This allows involving several different nonlinear optical processes simultaneously. The final part of the work describes various designs of integrated optical …
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Disordered Optics for Multidimensional Information Processing
… (DOE) for spectral imaging. We designed a spatially modulated DOE filter that can efficiently sample in the Fourier transformed domain and facilitate spectral image reconstruction. The DOE layer distinguishes the main Fourier spectral components, and the second spatial modulation layer …
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Active Pre-Touch Sensing: From Biology to Neuromorphic Biomimetic Artifacts
… such a device is measured at multiple positions, spatial modulation patterns can provide geometric information on the perturbing objects. To illustrate this, an electric field pre-touch sensor was used to make recordings of simple objects such as cubes and spheres. Interpreting the arising sensor …
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X-ray scattering studies of strongly correlated materials: orbital ordering in KCuF3 and stripe-like domain structures in BiFeO3 epitaxial thin films
… near the Fe L3 transition edge has revealed a spatial modulation of predominantly Fe 3d valence states with a period equal to that of the ferroelectric domain structure. The possibility of a magnetic origin to the Fe L3 edge resonant scattering is discussed. No O K edge resonant scattering was …
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Tunable mechanical bandgaps in elastic metamaterials: Patterning, straining, and spatiotemporal modulation
… has broad applications in practice. While the spatial modulation alone opens higher frequency band gaps, the temporal modulation alone can cause instability issue. We show that this instability can be mitigated by increasing damping coefficient. The combination of spatial temporal modulation …
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Optical nonlinear effects and photon pair production in modulated materials
… conditions. These require a direct temporal modulation of the boundary condition, which we achieve by temporally modulating the refractive index through the second order nonlinearity of the medium. We show that the key condition for this approach is that the medium is subwavelength in …
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Design and Optimization of Physical Waveform-Diverse and Spatially-Diverse Radar Emissions
… multiple-output (MIMO) mode. In this work, three spatially-diverse radar emission design methods are introduced that provide constant amplitude, spectrally-contained waveforms implemented via a digital array radar (DAR). The first design method, denoted as spatial modulation, designs the radar …
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Closed-loop multiple antenna aided wireless communications using limited feedback
… (MUT) and a recently proposed MIMO scheme called Spatial Modulation (SM).<br/><br/>The entire process of CSIT acquisition is investigated in this thesis, which includes pilot assisted CSI estimation, CSI quantisation at the receiver, as well as CSI reconstruction at the transmitter. A number of …
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Improvements of VLC (Visible Light Communication) transmissions under illumination constraints : theoretical studies and experiments
… cette thèse, nous étudions des techniques de modulation à haute efficacité spectrale pour la couche physique des VLC pour augmenter les débits tout en considérant la qualité de l’éclairage ainsi que les coûts d’implémentation. Des études numériques et expérimentales sont réalisées sur la …