This study is based on applying a non-linear mapping method, here the unscented Kalman filter; to estimate and optimize data rate resulting from the arrival rate having a Poisson distribution in an orthogonal frequency division multiplexing (OFDM) transmission system. OFDM is an emerging multi-carrier modulation scheme. With the growing need for quality of service in wireless communications, it is highly necessary to optimize resources in such a way that the overall performance of the system models should rise while keeping in mind the objective to achieve high data rate and efficient spectral methods in the near future. In this study, the results from the OFDM-TDMA transmission system have been used to apply cross-layer optimization between layers so as to treat different resources between layers simultaneously. The main controller manages the transmission of data between layers using the multicarrier modulation techniques. The unscented Kalman filter is used here to perform nonlinear mapping by estimating and optimizing the data rate, which result from the arrival rate having a Poisson distribution.

The exchange rate is one of the most challenging macroeconomic policy issues in any economy. There is a general agreement that policymakers should aim at avoiding real exchange rate misalignment. To avoid real exchange rate misalignment, it is important to identify the equilibrium real exchange rate. To identify the equilibrium real exchange rate it is necessary to understand the drivers of the real exchange rate, and investigate the extent to which the real exchange rate is driven by various determinants. Despite the fact that the real exchange rate is a very important component of macroeconomic policy, empirical investigation of the real exchange rate in Namibia is very limited. It is against this background that the objective of this study is to estimate the equilibrium real exchange rate and the resulting real exchange rate misalignment for Namibia during period 1970 to 2004. It also investigates the impact of real exchange rate misalignment on economic performance and competitiveness. The equilibrium real exchange rate and resulting real exchange rate misalignments were estimated using theoretical models and the application of time series econometric techniques. The fundamental approach model and the model of real exchange rate and real prices of commodities exports were estimated using the Johansen full information maximum likelihood technique. According to the estimation based on the fundamental model the real exchange rate is determined by terms of trade, openness of the economy and ratio of investment to GDP. Equilibrium real exchange rate was estimated and the results showed that the real exchange rate was misaligned. Since Namibia is a commodity exporting country the relationship between the real exchange rate and prices of commodities was also investigated. The analysis revealed that there is a long-run co-movement between real exchange rate and prices of commodity exports. Increase in prices of commodities causes the real exchange rate to appreciate. There was some overvaluation and undervaluation. The VAR methodology was implemented to test the impact of real exchange rate misalignment on economic performance and competitiveness. The analysis revealed that real exchange rate misalignment hampers economic growth and competitiveness. It is important for policymakers to monitor the real exchange rate and ensure that it does not diverge significantly from its equilibrium value. Reduction in real exchange rate misalignment is also important to ensure that the country achieves a high level of export and remains competitive in order to have a sustainable level of growth. As a commodity exporting country, Namibia can have either a flexible nominal exchange rate regime which facilitates slow change of relative inflation rate, or price and wage flexibility to facilitate the maintenance of the nominal exchange rate peg. Alternatively, Namibia is a good candidate for pegging the currency to the prices of export commodities because its export is concentrated on few products. This option implies that Namibia leaves the CMA. However, it is important to note that Namibia is a proponent of regional integration and a move away from the CMA will not be consistent with the plans of SADC to establish a monetary union by 2016. / Thesis (PhD (Economics))--University of Pretoria, 2007. / Economics / PhD / unrestricted

The present study addressed cognitive biases in anxiety and depression using the emotional Stroop task, and explored both the affective space and autonomic underpinnings of these disorders. In previous studies, anxiety has been associated with both an attentional bias toward threat information and low cardiac vagal control, as reflected in heart rate variability (HRV) indices. Depression has been linked to a memory bias for negative information; however, findings of low HRV for depression are mixed. The high comorbidity of these disorders renders such findings as difficult to interpret. In the present study, it was hypothesized that the negative affect groups (anxious, depressed, comorbid anxious/depressed) would have lower vagally mediated HRV across tasks compared to the control group and that the anxiety and depression groups would show biases for group specific words on the Stroop task. Results for the Stroop tasks generally support previous findings of an attention bias in anxiety. The comorbid anxiety/depression group generally showed lower vagal control across tasks compared to the other groups, although comparisons between the "pure" anxiety and depression groups and the controls were not significant. It is suggested that this is because the comorbid group had higher depression and anxiety than either of the "pure" groups. / Master of Science

Indiana University-Purdue University Indianapolis (IUPUI) / Autonomic control of the heart results in variations in the intervals between heart beats, known as heart rate variability. One of the defining components of autonomic control is the baroreflex, a negative feedback controller that balances heart rate and blood pressure. The baroreflex is under constant command from the branches of the autonomic nervous system. To better understand how the autonomic nervous system commands the baroreflex, a baroreflex reflexogenic animal protocol was carried out. Heart rate variability analysis and baroreflex sensitivity were used to quantify the neural control of the heart. This thesis reconfirmed the existence of sexually dimorphic properties in the baroreflex through the use of heart rate variability analysis and baroreflex sensitivity. It was discovered that there are many caveats to utilizing heart rate variability analysis, which have to be addressed both in the experimental protocol and the signal processing technique. Furthermore, it was suggested that the slope method for quantifying baroreflex sensitivity also has many caveats, and that other baroreflex sensitivity methods are likely more optimal for quantifying sustained activation of the baroreflex. By utilizing various heart rate variability signal processing algorithms to assess autonomic tone in Sprague-Dawley rats during rest and sustained electrical activation of the baroreflex, the null hypothesis was rejected.

Each year, 6.4 million automobile accidents account for approximately 40,000 deaths in the United States. With increasing requirements for automobile safety, computational models capable of simulating organ deformation/ injury during high impact scenarios would be extremely valuable for optimizing safety measures. Accurate experimental data is essential for the accuracy of the models; however, there has been a sparse investigation into high-strain biomechanics which is necessary to address organ/tissue response in high impact scenarios. Damage threshold criterion and damage evolution are other areas that have not been well studied. In vehicular accidents, damage to the liver is the most common cause of death after abdominal injury. High fidelity computational modeling with damage predictor is thus capable of describing liver tissue that is subjected to blunt impact. In this study, we address high strain biomechanics and damage evolution of liver tissue in an effort to generate valuable meaningful FE models.

Thesis advisor: Jaromir Nosal / This dissertation comprises three self-contained essays that investigate the determination and transmission of exchange rate fluctuations, as well as the impact of import quality on consumers’ gains from globalization. In the first chapter, “Decomposing the (In)Sensitivity of CPI to Exchange Rate", I examine the role of domestic frictions – distribution costs, variable markups and nominal rigidities – in explaining the low sensitivity of domestic prices to exchange rate fluctuations. I begin by modeling what the sensitivity of CPI to exchange rates is expected to be, given the presence of insensitivity in border prices and domestic frictions. Distribution costs, such as transportation and wholesaling costs, introduce a wedge between the retail price, on one side, and the border price of imports and the domestic producers’ costs, on the other. Similarly, domestic firms do not fully adjust their price to changes in their own cost because of changes in the desired markup or because prices are sticky. These frictions introduce wedges between the change in domestic producers’ costs and border prices following an exchange rate shock, and the response of domestic consumption retail prices. Using firm and transaction data from Chile, I document that domestic frictions account for 60% of the overall insensitivity of domestic CPI. Moreover, the presence of domestic frictions also impacts the sensitivity of domestic CPI: contrary to previous literature, most of the sensitivity arises from the direct consumption of imported final goods, rather than through the costs associated to imported inputs in the production of domestic goods. This is because domestic frictions dampen the response of domestically produced goods more significantly. In addition, I quantify a rich heterogeneity in the sensitivity across products, which stems from the interaction of domestic frictions and import exposure. These heterogeneities are relevant for the overall (in)sensitivity, as sectors with higher import exposure face also larger frictions. Overall, my results showcase the importance of domestic frictions and their heterogeneity in studying the response of domestic prices to exchange rate fluctuations, with implications for monetary policy in open economy and redistribution dynamics. In the second chapter, “Strategic Behavior and Exchange Rate Dynamics", joint work with L. Pollio, I examine the impact of heterogeneous investors with different degrees of price impact on exchange rate behavior. The huge trading volume in the currency markets, about $6 trillions per day, is highly concentrated among the market-making desks of few large financial institutions. However, models of exchange rate determination assume that investors take the equilibrium price as given, ignoring the presence of a few large investors who recognize the price impact of their decisions and can exert pressure on market prices. We incorporate heterogeneity in price impact, following of Kyle (1989), into a two-country, dynamic monetary model of exchange rate determination. Our theory of exchange rate determination with heterogeneity in price impact reveals that market structure is a key determinant of exchange rate dynamics. Strategic investors recognize their price impact, which leads them to trade less on any information and reduce the information loading factor of the exchange rate (price informativeness). The presence of strategic investors explains the weak explanatory power of macroeconomics variables in predicting exchange rates (exchange rate disconnect puzzle) and the excess volatility of the exchange rate relative to fundamentals (excess volatility puzzle). We also provide empirical evidence that supports our theoretical predictions by using trading volume concentration data from the NY Fed FXC Reports for 18 currencies from 2005 to 2019. We extend our theoretical framework to include another dimension of heterogeneity among investors, information heterogeneity, that provides similar qualitative predictions in terms of exchange rate dynamics. We demonstrate that both dimensions of heterogeneity are quantitatively relevant in explaining the disconnect of exchange rates and their excess volatility. In the third chapter, “The Quality of US Imports and the Consumption Gains from Globalization", joint work with D. Lashkari, I examine the role of quality improvement in shaping the gains from trade. The existing empirical literature indicates that globalization has offered consumers around the world access to a wider variety of products at cheaper prices. However, since the available data typically lacks detailed information on product characteristics, we may underestimate the value of imports for consumers if the quality of goods within each product rises over time. To overcome this limitation, we propose a novel methodology to estimate demand elasticity and infer unobserved quality using only data on prices and market shares. Our approach builds on the standard framework that models product quality as residual demand. This framework requires estimating price elasticities and the standard approach assumes CES demand and imposes uncorrelated supply and demand shocks. However, the latter assumption is untenable if we associate demand shocks with quality and generates an upward bias in the estimates of price elasticities. Our strategy circumvents this problem by restricting the dynamics of product quality to a Markov process. We apply our new methodology to the US customs data (1989-2006), and find that quality improvements contribute the most to the gains from trade in the US. Quality improvements have lowered the price of US imports relative to the CPI by 17%, with Chinese products contributing the most. In comparison, import prices have fallen by around 11% relative to the CPI and increasing variety has contributed an additional 4%. These findings demonstrate that accounting for quality is essential to better understand and measure the effects of international trade. / Thesis (PhD) — Boston College, 2023. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Economics.

A combination of fax and mail questionnaires were used to estimate consumption of wood based products by the U.S. cabinet industry and evaluate current management issues affecting the cabinet industry. Group 1 companies (>$20 million in sales) were contacted and sent a fax questionnaire. A random sample of 1034 Group 2 companies (<$20 million in sales and >10 employees) were sent a mail questionnaire. A total of 19 usable questionnaires were received from Group 1 companies and 217 usable questionnaires were received from Group 2 companies. Group 1 respondents averaged 1,108 employees and $125.81 million in sales. Group 2 respondents averaged 27 employees and $2.31 million in sales. A shortened questionnaire (questionnaire 2, one page) was sent to half of the Group 2 sample frame resulting in twice the response rate as that of the long questionnaire (questionnaire 1, three pages). Results indicated that the cabinet industry used an estimated 484 million board feet of hardwood lumber. Nearly 95% of the hardwood lumber purchases were grade 1 common or better. The most common used species were red oak (44%) and hard maple (24%). An estimated 58 million board feet of components and 68,344 doors were also purchased by cabinet manufacturers in 1999. Softwood lumber use was estimated at 25 million board feet, consisting primarily of white (49%) and southern yellow (36%) pine. The most commonly used panel products were particleboard and hardwood plywood, at an estimated 1,044 million square feet (1/2 inch basis) and 279 (3/8 inch basis) million square feet respectively. Other panel products used by the industry were medium density fiberboard, hardboard, and softwood plywood. Approximately 156 (any thickness) million square feet of veneer was used. Lumber purchases were primarily direct from sawmills (66%) for Group 1 companies and from wholesalers/distributors (53%) for Group 2 companies. Panel product purchases followed the same trend with Group 1 companies buying primarily direct from manufacturers (44%) and the majority of Group 2 purchases coming from wholesalers/distributors (84%). Group 1 companies sold their products through factory sales people (54%) and to home improvement/building supply centers (37%). Group 2 companies sold their products through factory sales people (77%) and to builders and remodelers (62%). The largest proportion of cabinet types sold by both Groups 1 and 2 were face frame kitchen cabinets (74% and 38% respectively). Companies from both groups reported producing certified (green) products. The majority of companies indicated they purchased some parts from outside sources. Companies from both groups reported considering alternative materials to substitute for wood. Products that were mentioned include strawboard, urban waste MDF, and plastic mouldings. Concerns rated highest by cabinet companies were finding qualified employees, increasing raw material prices, keeping qualified employees, and wood quality. / Master of Science

The aim of this study is to examine heart rate variability (HRV) alteration after the injection of atropine and saline and to determine if ensemble averaging affects the outcome of frequency domain analysis. The HRV data is pre-processed using ensemble averaging and then frequency domain and statistical analysis is done. The HRV readings originate from a previous study of four rats. Ensemble averaging reduces the mean drift effect in the data. The original and ensemble is then processed through an Fast Fourier Transform (FFT). The results show that the ensembled data allows frequency peaks and changes to be seen more clearly than the FFT of the original data set. Through statistical analysis it is also shown that the change in HRV from the atropine injection is much greater than the change in HRV from the saline injection.

No description available.

<p> Protein sequences display replacement rate heterogeneity across sites. In an earlier work, half of the causal site-wise variation in replacement rates was explained by a simple linear regression model consisting of terms for the solvent exposure of each residue, distance from the active site, and glycines in unusual main-chain conformations. Replacement rates vary not only across sites, they may also vary over time. In this study, we apply the linear regression model to phylogenies divided into subtrees to see if lineage-specific rate shifts have a structural basis that can be detected by the model. This approach is applied to two different data sets. The first set consists of phylogenies containing two representative structures, divided into subtrees such that one structure is present in each subtree. These structures have little or no obvious functional divergence between them. The model is tested with permutations of subtrees and structures from each subtree. While there is a slight effect of the specific structure on the fit of the model, the specific subtree has a greater effect. The second data set involves homologous structure pairs where the quaternary structure has changed at some point in the phylogeny. These pairs are examined to see how the change in constraint on the new interface sites affect the replacement rate, and its relationship with other structural factors. We find that the unique interfaces are as conserved as the shared ones, and they exhibit a different relationship between replacement rates and indicators of constraint than the shared interfaces or other protein sites. We also find that the unique interfaces display characteristic amino acid preferences that may identify interfaces which are still in the process of stabilizing. </p> / Thesis / Master of Science (MSc)