Cooperative communications have the ability to induce spatial diversity, increase channel capacity, and attain broader cell coverage with single-antenna terminals. This thesis focuses on the performance study of both unidirectional and bidirectional cooperative diversity networks employing the decode-and-forward (DF) protocol. For the unidirectional cooperative diversity network, we study the average bit-error rate (BER) performance of a DF protocol with maximum-likelihood (ML) detection. Closed-form approximate average BER expressions involving only elementary functions are presented for a cooperative diversity network with one or two relays. The proposed BER expressions are valid for both coherent and non-coherent binary signallings. With Monte-Carlo simulations, it is verified that the proposed BER expressions are extremely accurate for the whole signal-to-noise ratio (SNR) range. For the bidirectional cooperative diversity network, we study and compare the performance of three very typical bidirectional communication protocols based on the decode-and-forward relaying: time division broadcast (TDBC), physical-layer network coding (PNC), and opportunistic source selection (OSS). Specifically, we derive an exact outage probability in a one-integral form for the TDBC protocol, and exact closed-form outage probabilities for the PNC and OSS protocols. For the TDBC protocol, we also derive extremely tight upper and lower bounds on the outage probability in closed-form. Moreover, asymptotic outage probability performance of each protocol is studied. Finally, we study the diversity-multiplexing tradeoff (DMT) performance of each protocol both in the finite and infinite SNR regimes. The performance analysis presented in this thesis can be used as a useful tool to guide practical system designs for both unidirectional and bidirectional cooperative diversity networks. / Thesis (Master, Electrical & Computer Engineering) -- Queen's University, 2009-09-12 14:36:05.05

The purposes of this study were to: 1) evaluate how movement performance of the thumb and fingers were modified during manipulation of objects with and without fluids and 2) to quantify movement performance and accuracy during manipulation of objects, in two different modes of manipulation, i.e., pendulum and inverted pendulum. Twenty young healthy adults (age 24-35) were recruited and performed two predictable cyclic tracking tasks and episodic short-duration precision movement task. No change in movement performance observed in open-loop or episodic tasks. However, in closed-loop task, mode of manipulation (IP versus P) had a significant effect on amplitude consistency (P<0.001), and temporal accuracy (P<0.050).Fluid motion had a significant effect on RMS of index finger contact forces (p < 0.01) in episodic task. In conclusion, fluid motion had no significant effect on movement performance and accuracy. The quality of movement was better in pendulum mode than inverted pendulum movement.

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This thesis aims to tackle the theoretical challenges of characterizing the fundamental performance limits of amplify-and-forward (AF) cooperative networks and to resolve the practical challenges in the receiver design for AF systems. First of all, we study the Shannon-theoretic channel capacity which serves as a benchmark for practical wireless communications systems. Specifically, we derive exact expressions of the ergodic capacity in a single-integral form for general multi-branch AF relay networks with/without the direct link (DL). Moreover, we derive closed-form and tight upper bounds on the ergodic capacity, which facilitate the evaluation of the ergodic capacity. These expressions provide useful theoretical tools for the design of practical wireless AF relaying systems. We then tackle the practical challenges involved in the design of AF receivers, aiming to substantially reduce the channel state information (CSI) signaling overhead yet achieving satisfactory error performance. We take the maximum-likelihood (ML) and generalized likelihood ratio test (GLRT) approaches to develop detectors under four typical wireless communications scenarios with little/no knowledge of the CSI. Firstly, for a semi-coherent scenario where only the product of channel coefficients of each relay branch is known, we develop the ML symbol-by-symbol (SBS) detector, which reduces the instantaneous CSI signaling overhead by 50% while achieving comparable performance to the ideal coherent receiver. Secondly, for the noncoherent scenario with only the (second-order) channel statistics and noise variances, we develop a noncoherent ML SBS detector for AF networks employing differential modulations. Thirdly, for AF networks with only the knowledge of the noise variance, we develop a sequence detector using GLRT. Lastly, for a completely blind scenario where the instantaneous CSI, channel statistics, and noise variances are all unknown, we develop a GLRT-based sequence detector. The proposed detectors achieve significant performance improvements over the state-of-the-art counterparts. The conducted theoretical analysis and practical design will facilitate the design of reliable communications over wireless AF networks with reduced CSI requirement. / Thesis (Ph.D, Electrical & Computer Engineering) -- Queen's University, 2014-06-25 16:48:05.912

The purposes of this study were to: 1) evaluate how movement performance of the thumb and fingers were modified during manipulation of objects with and without fluids and 2) to quantify movement performance and accuracy during manipulation of objects, in two different modes of manipulation, i.e., pendulum and inverted pendulum. Twenty young healthy adults (age 24-35) were recruited and performed two predictable cyclic tracking tasks and episodic short-duration precision movement task. No change in movement performance observed in open-loop or episodic tasks. However, in closed-loop task, mode of manipulation (IP versus P) had a significant effect on amplitude consistency (P<0.001), and temporal accuracy (P<0.050).Fluid motion had a significant effect on RMS of index finger contact forces (p < 0.01) in episodic task. In conclusion, fluid motion had no significant effect on movement performance and accuracy. The quality of movement was better in pendulum mode than inverted pendulum movement.

This study investigates the role played by corporate governance in the firm's decision to disclose forward-looking information in financial reports, as well as the quality of such reports. More effective corporate governance has often been linked to voluntary disclosure within the annual report (Karamanou and Vafeas 2005). Similarly, recent studies document a positive association between reporting quality and the standard of corporate governance (Wright 2001). This study proposes that stronger corporate governance will be associated with increased forward-looking disclosures in financial reports and higher financial reporting quality. The results indicate that audit quality, the presence and quality of board committees and the overall efficacy of corporate governance are positively associated with forward-looking disclosures in 2000. However, corporate governance does not have a positive association with such disclosures in 2002. Regarding the relationship between financial reporting quality and corporate governance, audit quality is the only governance variable that yields a significant result and is only associated with higher reporting quality in 2002.

The objective of this thesis is to examine the extent to which the iron and steel industry in China has been a major contributor to the recent economic development and growth of the Chinese economy and whether this will continue. Key elements of China’s economic development model – THE CHINESE MODEL - based on the steel industry are presented and demonstrate the impact of China taking “great leaps forward” in its steel production capacity to become the world’s leading steel producer and one of the fastest growing economies. This bold step was undertaken at times when the global steel industry was burdened with overcapacity and economic pressures. At the same time, this thesis examines the role played by the Australian iron ore industry in supporting the Chinese steel industry through its iron ore trade with China and how this role will evolve. The development of the iron and steel industry in China reflects not just the role played in the overall expansion of the Chinese economy through technical input-output relationships, but it also reflects control and historical characteristics taken from China's social and political context. Starting from the views of Sun Yat Sen, and flowing through Mao Zedong, and then into later leaders, the steel industry was always intended to be the basis for the modernisation of the Chinese economy. The Great Leap Forward of the 1950s was an ill-founded reflection of that fundamental view, but the failure in that case did not cause a shift away from that basic perspective. Instead a more comprehensive perspective was provided and this came to the fore at the start of there form process in the early 1980s.The role of the steel industry in the recent modernisation of China is traced using the policy foundations and directions that were adopted combined with empirical data on the investment and growth in the industry, as well as the role of the output of the steel industry in the expansion of other industries in China. To the extent that conditions in China may be replicated in other countries, the Chinese experience using the iron and steel industry as the key element in the industrialisation of that economy will have important lessons. At the same time, this thesis demonstrates weaknesses in a development model that has the iron and steel industry as the leading sector. One major weakness is the reliance on imported raw materials and at this point the Chinese experience with Australia as a source of raw materials becomes relevant. Australia’s role as a reliable supplier and partner for the steel industry enabled the steel industry to expand in a low risk environment with respect to the price and availability of raw materials.

Master of Agribusiness / Department of Agricultural Economics / Vincent Amanor-Boadu / Generally, commodity prices immediately after harvest tend to be low because of supply glut and rise over time away from harvest as supply shrinks and demand remains virtually unchanged. Unfortunately, because many Malawian farmers do not have effective storage, they do not have any commodity for sale when prices are high. To help improve the income Malawian farmers may generate from their activities, this thesis explored the feasibility of hybridizing the two forms of price risk management systems in Malawi to minimize their individual weaknesses and enhance their collective benefits. The two risk management systems are forward contracts and warehouse receipt systems. Forward contracts allow farmers and their buyers to agree on a future delivery date and commodity price. On the agreed date, the farmer delivers the commodity and receives the agreed price. It allows farmers to pass downward price risk to buyers and guarantees a fixed price. As private transactions, forward contracts are not regulated by the Government, and present opportunism and enforcement challenges. Warehouse Receipt System (WRS) enables farmers to deposit their crop in the care of a warehouse operator and sell the crop when and where they choose. Farmers, therefore, incur both upside and downside price movement but avoid some of the opportunism and enforcement challenges presented by forward contracts. The thesis explored the net benefits of developing a hybrid system that allow forward contracts with warehouse receipt enforcement mechanisms. Thus, farmers are guaranteed a minimum price at some future date and the deposited commodity is used as the security supporting the guaranteed minimum price. The buyer also deposits a performance bond as commitment to purchase the commodity. The costs associated with these transactions are real and could affect participation. The thesis provides a process for assessing these transaction costs and incorporating them into the effectiveness of forward contracts, warehouse receipt systems and the hybrid program. The mathematical model example has proved that the hybrid system guarantees a fixed margin to the farmer over and above the harvest price and WRS cost as opposed to fluctuating margins under WRS alone. The thesis has identified three factors that can lead to the successful implementation of this hybrid system in Malawi and they include: the availability of the warehouse receipt bill, reliable warehouse certification which is done by AHCX and ACE on third party warehouse operators; and the availability of performance guarantee assuring that the quantities and quality of goods match those specified by the warehouse receipt. The thesis has also identified two factors that could hinder a successful implementation of this hybrid program and they include: first, low scale of warehousing operations under WRS which could deny most farmers a chance to access and benefit from this hybrid sytem and the commodity exchanges may not benefit from the economies of scale provided by large volumes of commodities produced in rural areas. Second, the absence of a harmonized national grading standard which possess a challenge when engaging in international trade. Finally, the thesis has made three recommendations for the successful implementation of the hybrid program as follows: Taking the system close to the producers to mitigate potentially high transportation costs; educating and selling the system to the stakeholders to increase adoption rate; and push for the implementation of national standardized grading regulations.

In this dissertation harmonic current, harmonic torque originated at the load and harmonic torque originated at the motor, where modeled and treated via closed loop control. The dissertation propose a remedy for cancelling harmonic current by placing the proposed adaptive feedforward controller (AFC) in parallel with the FOC current control. Similarly, harmonic torque load was cancelled by proposing an AFC in parallel with the speed control loop. Harmonic torque originated in the motor mainly due to harmonic flux where cancelled through the estimation of harmonic flux, which was achieved by a novel Minimal Parameter Harmonic Flux Estimator (MPHFE). The latter is formulated such that the inductance, resistance, and stator current and its derivative are not necessary for the estimation of the harmonic eflux. This was achieved by forcing the harmonic current induced by the harmonic flux component to zero through the combined action of a Field-Oriented Controller (FOC) and a feed-forward controller. Subsequently, the harmonic flux can be obtained directly from the estimated harmonic back-EMF without the involvement of other motor parameters. Finally, the estimated flux is used in conjunction with a comprehensive analysis of the motor harmonic torque to determine the stator current compensation to eliminate the torque harmonic. A systematic approach to assign the parameter of the AFC controller were developed in this dissertation. Furthermore, multiple experiments were conducted to demonstrate the efficacy of the proposed control schemes harmonics.

In this thesis, we study three topics in optimal portfolio selection that are relevant to the theory of forward investment performance processes. In Chapter 1, we develop a connection between the classical mean-variance optimisation and time-monotone forward performance processes for infinitesimal trading times. Namely, we consider consecutive mean-variance problems and we show that, for an appropriate choice of the corresponding mean-variance trade-off coefficients, the wealth process that is generated converges (as the trading interval goes to zero) to the optimal wealth process generated by a time-monotone forward performance process. The choice of the trade-off coefficients is made in accordance to the evolution of the risk tolerance process of the forward performance process. This result allows us to provide a fresh view on the issue of time-consistency of mean-variance analysis, for we propose a method to update mean-variance risk preferences forward in time. As a by-product, our convergence theorem generalises a result by Gy&ouml;ngy (1998) on the convergence of the Euler scheme for SDEs. We also provide novel results on the Lipschitz regularity of the local risk tolerance function of forward investment performance processes. The material in this chapter is joint work with Marek Musiela and Thaleia Zariphopoulou. Chapter 2 combines forward investment theory and partial information. Specifically, we construct forward investment performance processes in models where the drift is a random variable distributed according to a known distribution. The forward performance processes we consider are of the type U(t,x) = u(t,x, R_t), where R. denotes the process of cumulative excess returns, and u(t,x,z):[0,&infin;) &times; &Ropf; imes &Ropf;^N &xrarr; &Ropf; is such that u(t,.,z) is a utility function satisfying Inada's conditions. We derive the Hamilton-Jacobi-Bellman (HJB) equation for u(.). The HJB equation is linearised into the ill-posed heat equation; then, using the multidimensional version of Widder's theorem, we fully characterise the solutions to this equation in terms of a collection of positive measures; the result is an integral representation of the convex conjugate function of u(t,.,z). We construct several examples, and we show how these can be combined, in the dual domain, to generate mixtures of forward investment performance processes. We also show that the volatility of these processes is intrinsic, in that it is not generated by changes of num&eacute;raire/measure. In Chapter 3, we provide an extension of the Black-Litterman model to the continuous time setting. Our extension is different from, and complements that of, Frey, Gabih, and Wunderlich (2012) and Davis and Lleo (2013). Specifically, we develop a novel robust estimator of instantaneous expected returns which is continuously shrunk towards the predictions of an asset pricing theory, such as the CAPM. We derive this estimator fairly explicitly and study some of its properties. As in the Black-Litterman model, such an estimator can be used to make optimal asset allocation problems in continuous time more robust with respect to estimation errors. We provide explicit solutions to the problem of maximising expected power utility of terminal wealth, when our estimator is used to estimate the drift. As an example, we illustrate our results explicitly in the case of a multifactor model, where Arbitrage Pricing Theory predicts that alphas should be approximately zero.