Previous research has evaluated error correction procedures to assess their effectiveness, yet few studies have evaluated preferences for these procedures. An alternating treatments design was used to compare the effects of four error correction procedures: model, single response repetition (SRR), multiple response repetition (MRR), and single response repetition with an embedded distracter trial (SRR-D), on the acquisition of sight words for three adolescent males. Preference for the procedures was assessed by using a concurrent chains procedure consisting of forced choice and free choice presentations. Results demonstrated that all participants performed best with a specific error correction procedure. Participant 1 showed a moderate preference for his most effective error correction procedure. Participant 2 demonstrated a slight preference for the SRR procedure which did not correlate with his most effective error correction procedure, SRR-D, and participant 3 did not demonstrate preference for any of the procedures. These findings suggest that error correction procedures should be evaluated and individualized for each learner. Although a moderate preference for a procedure was demonstrated with only one participant, future research should continue to use and refine these procedures to incorporate learner preference in all teaching strategies. / Teaching & Learning

No / Abstract: Error control techniques are designed to ensure reliable data transfer over unreliable communication channels that are frequently subjected to channel errors. In this paper, the effect of applying a convolution code to the Scattered Random Network Coding (SRNC) scheme over a multi-hop wireless channel was studied. An interleaver was implemented for bit scattering in the SRNC with the purpose of dividing the encoded data into protected blocks and vulnerable blocks to achieve error diversity in one modulation symbol while randomising errored bits in both blocks. By combining the interleaver with the convolution encoder, the network decoder in the receiver would have enough number of correctly received network coded blocks to perform the decoding process efficiently. Extensive simulations were carried out to study the performance of three systems: 1) SRNC with convolutional encoding, 2) SRNC; and 3) A system without convolutional encoding nor interleaving. Simulation results in terms of block error rate for a 2-hop wireless transmission scenario over an Additive White Gaussian Noise (AWGN) channel were presented. Results showed that the system with interleaving and convolutional code achieved better performance with coding gain of at least 1.29 dB and 2.08 dB on average when the block error rate is 0.01 when compared with system II and system III respectively.

This thesis studies the relationship between the trade balance ratio between Sweden and Norway and the real exchange rate. Following a real depreciation of the Swedish crown (SEK) against the Norwegian krone (NOK), the trade balance ratio of Swedish exports to Norway to Swedish imports from Norway (X/M), is expected to initially fall due to lower earnings from the exports and higher expenses associated with imports. As the goods become cheaper, the demanded quantity is expected to increase, which is how the J-curve appear. J-curve builds on the Marshall-Lerner theory, which says that if the sum of price elasticities of exports and imports is elastic, the Swedish trade balance will improve as a result of the real depreciation of SEK. A test for cointegration is performed to see if there is a significant long-run relationship between the variables. This relationship is studied at two different frequences of observations, quarterly and annually. Then the Autoregressive Distributed Lag model, ARDL is used to analyse the J-curve. One of the conclusions of the results is that although no significant relationship could be found at monthly or quarterly observations, there is a J-curve present at annual level.

No / We develop a non-linear Markov error correction approach to examine the general co-integration relation between the H- and A-prices of cross-listed Chinese stock issuers across the period January 1999 to March 2009. We unravel three important dimensions of this relation. These pertain to (i) the long-run expectation of the H- (to A-price) discount; (ii) the level of short-run co-movement in prices; and (iii) the magnitude of error corrections. Findings point to significant improvements in all three areas. Policy and corporate governance change appears to be the principal force driving the efficiency gains. Weakening informational asymmetries underlie much of the change in the markets’ relative pricing. In contrast, sentiment effects strongly underpin the contemporaneous response and error correction adjustments. Finally, the escalating Global Financial Crisis of 2008 appears to have not only bolstered the A- and H-markets’ short-term pricing dynamic but also temporarily increased the long-term H-share discount.

Yes / This paper develops a model of optimal choice over an array of different assets, including domestic and foreign bonds, domestic and foreign equities and domestic and foreign real money balances in order to examine the determination of the real exchange rate in the long-run. The model is tested empirically using data from the UK and the USA. The results show that all the coefficients of the model are right signed and significant and consequently financial assets may play a significant role in the determination of the real exchange rate.

No / Orthokeratology (ortho-k) is the process of deliberately reshaping the anterior cornea by utilising specialty contact lenses to temporarily and reversibly reduce refractive error after lens removal. Modern ortho-k utilises reverse geometry lens designs, made with highly oxygen permeable rigid materials, worn overnight to reshape the anterior cornea and provide temporary correction of refractive error. More recently, ortho-k has been extensively used to slow the progression of myopia in children. This report reviews the practice of ortho-k, including its history, mechanisms of refractive and ocular changes, current use in the correction of myopia, astigmatism, hyperopia, and presbyopia, and standard of care. Suitable candidates for ortho-k are described, along with the fitting process, factors impacting success, and the potential options for using newer lens designs. Ocular changes associated with ortho-k, such as alterations in corneal thickness, development of microcysts, pigmented arcs, and fibrillary lines are reviewed. The safety of ortho-k is extensively reviewed, along with an overview of non-compliant behaviours and appropriate disinfection regimens. Finally, the role of ortho-k in myopia management for children is discussed in terms of efficacy, safety, and potential mechanisms of myopia control, including the impact of factors such as initial fitting age, baseline refractive error, the role of peripheral defocus, higher order aberrations, pupil size, and treatment zone size. / The CLEAR initiative was facilitated by the BCLA, with financial support by way of Educational Grants for collaboration, publication and dissemination provided by Alcon and CooperVision.

Virginia Tech researchers have developed a broadband channel sounder that can measure channel quality while a wireless network is in operation. Channel measurements from the broadband sounder hold the promise of improving TCP/IP performance by trigging configuration changes in an adaptive data link layer protocol. We present an adaptive data link layer protocol that can use different levels of forward error correction (FEC) codes and link layer automatic retransmission request (ARQ) to improve network and transport layer performance. Using a simulation model developed in OPNET, we determine the effects of different data link layer protocol configurations on TCP/IP throughput and end-to-end delay using a Rayleigh fading channel model. Switching to higher levels of FEC encoding improves TCP/IP throughput for high bit error rates, but increases end-to-end delay of TCP/IP segments. Overall TCP/IP connections with link layer ARQ showed approximately 150 Kbps greater throughput than without ARQ, but lead to the highest end-to-end delay for high bit error rate channels. Based on the simulation results, we propose algorithms to maximize TCP/IP throughput and minimize end-to-end delay using the current bit error rate of the channel. We propose a metric, carrier-to-interference ratio (CIR) that is calculated from data retrieved from the broadband channel sounder. We propose algorithms using the carrier-to-interference ratio to control TCP/IP throughput and end-to-end delay. The thesis also describes a monitor program to use in the broadband wireless system. The monitor program displays data collected from the broadband sounder and controls the settings for the data link layer protocol and broadband sounder while the network is in operation. / Master of Science

No / Orthogonal frequency division multiplexing (OFDM) is pronounced in wireless communication systems. Methods for improving the performance of the OFDM-based systems are mostly sought. A method of doing this involves error correction coding and another, a better multicarrier modulation kernel. In this work, convolutional error correction coding with interleaving is introduced in wavelet multicarrier modulation OFDM system (wavelet-OFDM) to improve the performance of multicarrier systems as the signal traverses the multipath and noisy transmission channels. This is compared with FFT-based multicarrier modulation (FFT-OFDM). Results show that coded wavelet-OFDM saves more than a half of the transmit power than the uncoded wavelet. Also it will be shown that, the interleaved and non-interleaved coded wavelet-OFDM well outperform interleaved coded and non-interleaved coded FFT-OFDM systems respectively.

A modified, single error-correcting, and double error detecting Hamming code, hereafter referred to as modified SEC-DED Hamming code, is proposed in this research. The code requires fewer logic gates to implement than the SEC-DED Hamming code. Also, unlike the popular Hsiao's code, the proposed code can determine the error in the received word from its syndrome location in the parity check matrix. A detailed analysis of the area and power utilization by the encoder and decoder circuits of the modified SEC-DED Hamming code is also discussed. Results demonstrate that this code is an excellent alternative to Hsiao's code as the area and power values are very similar. In addition, the ability to locate the error in the received word from its syndrome is also of particular interest. Primitive polynomials play a crucial role in the hardware realizations for error-correcting codes. This research describes an implementation of a scalable primitive polynomial circuit with coefficients in GF(2). The standard cell area and power values for various degrees of the circuit are analyzed. The physical design of a degree 6 primitive polynomial computation circuit is also provided. In addition to the codes, a background of the already existing SPX GCD computation algorithm is provided. Its implementation revealed that the combinational implementation of the SPX algorithm utilizes a significantly lesser area than Euclid's algorithm. The FSMD implementation of the SPX algorithm reduces both dynamic and leakage power consumption. The physical design of the GCD computation using the SPX algorithm is also provided.

Made available in DSpace on 2016-03-15T19:25:37Z (GMT). No. of bitstreams: 1 Eli Hadad Junior.pdf: 290403 bytes, checksum: 413b010b2b66c535b71df800b9626c61 (MD5) Previous issue date: 2011-08-10 / The dissertation analyzes data of the Brazilian household consumption and income between the years 1947 and 2009. The study aims to evaluate to what extent the aggregate consumption of Brazilian household may approximate be a random walk. The dissertation uses Johansen's cointegration techniques (1988, 1991) and super exogeneity tests as proposed by Engle and Hendry et al. (1983). The dissertation attempts to evaluate whether interventions that affect consumption will impact the dynamics of aggregate income. These interventions can occur through credit policies and tax changes, among other macroeconomic shocks. Finally, a decomposition is made following the methodology proposed by Gonzalo-Granger (1995) and evaluating the importance of shocks in permanent and temporary changes in consumption. / A dissertação analisa os dados de consumo e renda das famílias brasileiras entre os anos de 1947 e 2009. O trabalho visa avaliar em que medida o consumo agregado das famílias brasileiras pode ser bem aproximando a partir de um passeio aleatório puro. O trabalho utiliza técnicas de cointegração de Johansen (1988, 1991) e testes de super exogeneidade na forma proposta por Hendry, Engle et al. (1983). A dissertação procura avaliar se intervenções que afetam o consumo das famílias geram impacto na dinâmica da renda agregada das mesmas. Tais intervenções podem ser por políticas de crédito, alterações tributárias, choque macroeconômicos entre outras. Por fim uma decomposição entre fatores permanentes e transitórios será feita pela metodologia proposta por Gonzalo-Granger (1995) com o objetivo de avaliar-se a importância dos choques permanentes e transitórios para as variações do consumo.