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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
121

Adaptive Joint Source/Channel Rate Allocation Policies For Delay Sensitive Applications Over Fading Channels

Thejaswi, Chandrashekhara P S 10 1900 (has links) (PDF)
No description available.
122

A Study of Colorfastness to Laundering of Certain Percales Bearing Two Different Labels

Griffith, Nona L. January 1943 (has links)
The present study is to compare the fading properties due to home laundering methods of certain percales bearing printed labels, "Guaranteed Fast Color," with samples representing similar colors labeled, "Fast to Washing."
123

Hardwarový simulátor únikového kanálu / Fading channel hardware simulator

Pirochta, Pavel January 2010 (has links)
Fading channel is a communication channel that experiences different interference and fading due to multi-path signal propagation. The fading channel is designed by the finite impulse response filter with the time-varying impulse characteristic. The realisation of this filtr is based on the TDL (Tapped Delay Line) model, which simulate signal delay and signal attenuation in each branch. The aim of this thesis is to create the VHDL design of selected fading channel simulator and its description for hardware implementation into the FPGA.
124

Discrimination Training: A Comparison of Two Procedures for Presenting Multiple Examples Within a Fading and Non-Fading Paradigm

Van Laarhoven, Toni, Johnson, Jesse W., Repp, Alan C., Karsh, Kathryn G., Lenz, Mark 01 January 2003 (has links)
When teaching discriminations, many researchers and practitioners recommend presenting multiple examples of both the correct and incorrect stimuli. To test this suggestion, we compared two procedures for presenting multiple examples. In one, multiple examples across trials (ME, Across), one correct (S+) and one incorrect (S-) stimulus were presented each trial; examples then changed across trials. In another procedure, multiple examples within trials (ME, Within), three stimuli (either 2 S+'s and 1 S-, or 1 S+ and 2 S-'s) were presented each trial; examples again changed across trials. Two experiments were conducted to test these procedures. The first procedure used a non-fading program to teach discrimination; the second used a fading procedure. In the first experiment, we taught 10 persons to identify words under these two procedures. The former procedure was superior in acquisition; the latter procedure, however, was better under generalization for most participants. In the second experiment, we presented the two procedures within a fading paradigm. The results replicated those in Experiment 1: ME, Across was better for acquisition, but ME, Within was better for generalization. Results were discussed and follow-up studies suggested.
125

Analysis and Optimization of Massive MIMO Systems via Random Matrix Theory Approaches

Boukhedimi, Ikram 01 August 2019 (has links)
By endowing the base station with hundreds of antennas and relying on spatial multiplexing, massive multiple-input-multiple-output (MIMO) allows impressive advantages in many fronts. To reduce this promising technology to reality, thorough performance analysis has to be conducted. Along this line, this work is focused on the convenient high-dimensionality of massive MIMO’s corresponding model. Indeed, the large number of antennas allows us to harness asymptotic results from Random Matrix Theory to provide accurate approximations of the main performance metrics. The derivations yield simple closed-form expressions that can be easily interpreted and manipulated in contrast to their alternative random equivalents. Accordingly, in this dissertation, we investigate and optimize the performance of massive MIMO in different contexts. First, we explore the spectral efficiency of massive MIMO in large-scale multi-tier heterogeneous networks that aim at network densification. This latter is epitomized by the joint implementation of massive MIMO and small cells to reap their benefits. Our interest is on the design of coordinated beamforming that mitigates cross-tier interference. Thus, we propose a regularized SLNR-based precoding in which the regularization factor is used to allow better resilience to channel estimation errors. Second, we move to studying massive MIMO under Line-of-Sight (LoS) propagation conditions. To this end, we carry out an analysis of the uplink (UL) of a massive MIMO system with per-user channel correlation and Rician factor. We start by analyzing conventional processing schemes such as LMMSE and MRC under training-based imperfect-channel-estimates, and then, propose a statistical combining technique that is more suitable in LoS-prevailing environments. Finally, we look into the interplay between LoS and the fundamental limitation of massive MIMO systems, namely, pilot contamination. We propose to analyze and compare the performance using single-cell and multi-cell detection methods. In this regard, the single-cell schemes are shown to produce higher SEs as the LoS strengthens, yet remain hindered by LoS-induced interference and pilot contamination. In contrast, for multi-cell combining, we analytically demonstrate that M-MMSE outperforms both single-cell detectors by generating a capacity that scales linearly with the number of antennas, and is further enhanced with LoS.
126

Peer-Implemented Script Fading to Promote Play-Based Statements in Children With Autism

Rosdahl, Jessie 01 May 2016 (has links)
In this study, we examined the effect of peer-implemented script fading procedures on the frequency of independent statements of play by children with autism spectrum disorder (ASD) in a classroom setting. The target children included five 5-year-old individuals with ASD with the ability to speak in three- to five-word phrases but did not initiate play with peers. We trained typically developing peers, ages 5 to 6, on how to implement procedures, prompt correct responses, systematically fade scripts, and interact with the target children. We used a script-fading intervention, including auditory scripts that prompted initiation of play with peers. We conducted sessions in an open area of a classroom using a preferred toy set and two additional toy sets for generalization. Following training, we found that peers implemented procedures with fidelity and target participants showed an increase in independent statements of play, both scripted and unscripted.
127

The Effects of Simultaneous Script-Training and Fading Procedures on the Mand Variability of Children with Autism

Kelley, Kristen N. 01 May 2013 (has links)
Individuals with autism often display rote and repetitive responding across behavioral topographies. One area that is often affected is the individual’s verbal repertoire. In an attempt to build and expand verbal repertoires, script and script fading procedures have often been implemented to teach individuals new and varied verbal behavior. Script training and fading procedures have also been used specifically to remediate deficits in an individual’s mand repertoire. Researchers have examined the effects of script training and fading procedures on the variability within an individual’s mand repertoire. This line of research is of great importance since a lack of variability in mands can limit an individual’s access to desired and/or needed items as well as social interactions. In the present study, we implemented simultaneous script training and fading procedures to increase the variability of mands used by three preschool-aged children (one male and two females) diagnosed with autism. We implemented these procedures in an attempt to promote mand variability using antecedent only procedures and to teach variability explicitly in our script training and fading preparation. It was also our goal to address some of the limitations that arose in the previously conducted mand variability studies, namely, the suppression of the default mand frame. At the conclusion of the study, and following procedural modifications, all three participants demonstrated an increase in variability of mand frames. This increase was observed following the inclusion of extinction procedures and following low levels of variability while using antecedent-only procedures. Participants in this study demonstrated an average of one mand frame following antecedent-only procedures and this increased to an average of three mand frames following the inclusion of extinction procedures. The combination of the antecedent procedures and extinction further increased variability across participants. The need for the extinction condition led to many limitations in this study including the limitations analyzed in the simultaneous script training and fading procedures.
128

Simulation of Alamouti Coded MIMO Signals over a Nakagami Fading Channel

Manamohan, Swathi 23 September 2019 (has links)
No description available.
129

An Introduction to Local Multipoint Distribution Services with an Investigation of the Effects of Vegetation on the Radio Channel

Manning, Edward Patrick 28 January 1999 (has links)
This thesis takes the reader through an overview of issues pertinent to Local Multi-point Distribution Services (LMDS). The reader will first learn what LMDS is and then review the system architectures that are made available for LMDS technologies. After summarizing the basics of LMDS, we will compare it with some competing technologies. The reader will then be guided through the aspects of millimeter (mm) wave radio link design. This should be a good lead into the experiment section, since it is suspected that the reader would want to be aware of what design techniques are involved in mm-wave radio link design and what issues may pose potential problems and how they may be mitigated. Of the potential problems posed in the mm-wave radio link design section, one will be further investigated experimentally. This is the investigation of the effect of vegetation on the magnitude, phase and error vector magnitude (EVM) performance of an LMDS channel. The motivation for this experiment came from the review earlier work, which showed an unexpected relationship between carrier to noise ratio (C/N) and bit error rate BER. / Master of Science
130

Optimal Detection and Estimation for Echo Ranging in a Randomly Fading Environment

Mark, Jon Wei 03 1900 (has links)
<p> A self-synchronized echo ranging system with optimum utilization of signal estimation and detection strategies has been designed and simulated. A binary convolution code has been utilized to modulate the transmitter signal. The random medium is modelled by a vector sum of a fixed and a random component; the medium fading process has a Rician distribution density. A channel estimator has been derived using a maximum a posteriori probability criterion. The estimator is an adaptive processor whereby the variance of the medium fading process is recomputed during each updating cycle. The estimator attempts to provide a coherent input to the correlator. An optimum processor for the signalling described is an ordered serial estimator-correlator combination. It is conjectured that the estimator offers an improvement in signal processing gain of approximately 5 dB over and above the non-optimized system. Accompanying this is an improvement in peak-to -sidelobe ratio and in false alarm probability. A 3 bit (8 level) quantized system is conjectured to be a 'good' trade-off between degradation in system performance and simplification in system implementation.</p> / Thesis / Master of Engineering (MEngr)

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