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A Dissertation submitted in ful llment of the requirements for the degree of Master of Science in the School of Electrical and Information Engineering January, 2017 / Permutation codes provide the required redundancy for error correction in a noisy communication channel. Combined with MFSK modulation, the outcome produces an e cient system reliable in combating background and impulse noise in the com- munication channel. Part of this can be associated with how the redundancy scales up the amount of frequencies used in transmission. Permutation coding has also shown to be a good candidate for error correction in harsh channels such as the Powerline Communication channel. Extensive work has been done to construct permutation code books but existing decoding algorithms become impractical for large codebook sizes. This is because the algorithms need to compare the received codeword with all the codewords in the codebook used in encoding. This research therefore designs an e cient soft-decision decoder of Permutation codes. The decoder's decision mechanism does not require lookup comparison with all the codewords in the codebook. The code construction technique that derives the codebook is also irrelevant to the decoder. Results compare the decoding algorithm with Hard-decision plus Envelope Detec- tion in the Additive White Gaussian Noise (AWGN) and Rayleigh Fading Channels. The results show that with lesser iterations, improved error correction performance is achieved for high-rate codes. Lower rate codes require additional iterations for signi cant error correction performance. The decoder also requires much less comup- tational complexity compared with existing decoding algorithms. / MT2017

Algebra I encompasses several topics that serve as a basis for students’ subsequent mathematics courses as they progress in school. Some of the key topics that students struggle with is solving linear equations and algebraic word problems. There are several factors that may contribute to this ongoing struggle for students such as the structure of the textbooks, the teacher instruction and misconceptions of components of algebraic equations. A promising solution to the potential contributing factors is concrete fading. In this study, concreteness fading refers to an instructional technique that represents topics in a particular sequence from a concrete, real-world representation to a semi-concrete diagram (e.g., tape diagram) to an abstract representation (e.g., algebraic equations). The current study aims to investigate the influence concrete fading has on student learning while studying concrete fading in two ninth grade Algebra I general education classes at an urban high school. In particular, the study aims to answer the following: 1) What are some ways that students who received concrete fading think differently than the control group? 2) How do these differences seem to be related to the intervention? Both classes were taught by the same teacher. One class was assigned to the treatment group that received the concrete fading lessons and the other class was assigned to the control group that was taught as business as usual by the teacher. The study was intended to be quasi-experimental study, but due to challenges, it was primarily qualitative in nature focusing on eight students where the analysis included analyzing student work and student interviews responses along with quantitative analysis of the pre and two post-tests. Results revealed that the treatment group does think differently than the control group based on student work and the interview responses. / Math & Science Education

In order to establish a secure connections in the wireless environment, cryptographic methods may require an exchange of a key or secret. Fortunately, the environment provides randomness due to multi-path fading that can be exploited by physical-layer security algorithms to help establish this shared secret. However, in some cases, multi-path fading might be absent or negligible; therefore, we look for artificial ways to increase randomness. In this thesis, we explore antenna radiation variation by altering the phase between two antennas as a means of creating artificial fading. We construct a model of the antenna gain variation by analyzing the radiation pattern and run Monte-Carlo simulations to compare our approach to a base case with only multi-path fading. We then empirically collect data in order to confirm our analysis. Finally, we incorporate this model in a prominent security algorithm to demonstrate the improvements in security possible through such an approach.

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[pt] Neste trabalho desenvolve-se detalhadamente as passagens intermediárias necessárias ao cálculo da probabilidade de erro considerando a interferência entre símbolos provocada pelo desvanecimento seletivo de freqüência no canal de comunicações. Compara-se os resultados distintos obtidos por Bello e Nelin e por Bailey e Lindenlaub para a probalidade de erro considerando a inteferencia de dois pulsos adjacentes ao amostrado. Conclui-se que o trabalho realizado pelos últimos pode ser considerado correto e comenta-se as aproximações por eles efetuadas. Desenvolve-se uma sistemática de cálculo que permite calcular sem aproximações, não só a probabilidade de erro considerando, a interferência de quatro pulsos adjacentes ao amostrado como também a de dois pulsos. Cumpre ressaltar que o estudo foi feito para um sistema de comunicação digital com receptores diferencialmente coerentes casados a sinais modulados por deslocamentos de fase - DPSK. A seqüência de pulsos binários como sendo transmitida através de um canal com desvanecimento seletivo de freqüência puro com função autocorrelação de freqüência gaussiana. / [en] In this work it is shown in detail the necessary steps to compute the erros probability taking into account the intersymbol interference due to the frequency-selective fading in the communication channel. A comparison is made between Bello and Nelin’s and Bailey and Lindenlaub’s results for the error probabilities with intersymbol interference due to two adjacent pulses with the sample pulse. It is concludes that the work done by the latter can be considered correct and the assumed approximations are discussed. There is developed a means of computation which permits obtaining without approximation the error probabilities with intersymbol interference due to four and two adjacent pulses to the sampled pulse: It is necessary to remark that this work was done for a digital communication system with differentially coherent matched filter receivers. The binary pulse sequence was transmitted through a channel with pure frequency selective fading described by its Gaussian frequency autocorrelation function.

Current research indicates that the inability to spontaneously communicate needs or wants may result in the acquisition of unconventional forms of requesting such as aggression and tantrums. This in turn limits the amount of access that students with autism have to neurotypical peers and social environments. The purpose of this study was to investigate the effect of using a stimulus control transfer procedure on the acquisition of spontaneous mands. Four school-aged children with autism, two boys and two girls, participated in the study. A multiple baseline design across participants was utilized to demonstrate a functional relation between the stimulus control transfer procedures and the rate of spontaneous mands. Measurement variables included the frequency of spontaneous versus multiply-controlled mands during discrete trial training on a variety of verbal operants. Effectiveness of the intervention was analyzed through visual analysis and the magnitude of effect was assessed through effect size. Visual analysis indicated that three of the four participants learned to spontaneously mand for items out of view and demonstrated generalization across targets, staff and environments. The effect size for three participants were large (d = 1.94; d = 2.2; and d = 1.4), whereas the outcome of intervention for one participant (d = 0.98) indicated moderate effect. The overall (d = 1.15) outcome demonstrated a large effect of the intervention on the rate of mands. Based on the results of this study, it is recommended that early and intensive behavior intervention programs for children with autism incorporate this type of procedure for socially significant outcomes.

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