Multilayered structures have many application in industry and society: they have peculiar properties and serve a variety of purposes, like structural support, thermal insulation, vibrational and acoustic isolation. This thesis concerns the prediction of sound transmission in multilayered structures. Two problems are herein investigated: the transmission of energy through structures and the transmission of energy along structures. The focus of the analysis is on the mid to high frequency range. To predict sound transmission in these structures, statistical energy analysis (SEA) is used.SEA models are devised for the prediction of the sound reduction index for two kinds of multilayered structures, double-walls used in buildings and trim-panels in vehicles; the double-walls comprise an air cavity in between flat plasterboard or glass plates, whereas the trim-panels a porous layer in between curved aluminium and rubber layers. The SEA models are based upon the wave-types carrying energy. The novelty in these SEAs is an element describing the waves in the air cavity, or in the porous layer, fully coupled to the mass-impeded external layers. Compared to measurements, the proposed SEA performs well: for double-walls, it performs better than previous models; for trim-panels, it is an original result. The parameters of the new SEA element, such as modal density, are derived from the coupling equations describing the fully coupled waves. For double-walls, these equations are derived via Newton's laws. For trim-panels, a variational approach based upon a modified Hamilton's principle valid for non-conservative systems is preferred, because it is a powerful machinery for deriving equations of motion and coupling conditions of a medium as complex as the porous layer. The modified Hamilton's principle for non-conservative systems is based upon a self-adjoint functional analogous to the Lagrangian, inspired by Morse and Feshbach's construction. A self-adjoint variational principle for Biot's equations in the displacement formulation is devised. An equivalent mixed formulation is obtained changing the coordinates of the displacement formulation via Lagrange multipliers. From this mixed formulation, the Lagrangian for a porous material with a limp frame is derived, which yields the continuity of the total displacement of the porous layer. Lagrange multipliers help to obtain the correct coupling functionals between a porous material and a solid. The Lagrange multipliers introducing the continuity of the frame and the solid displacements equal the traction of the in-vacuo frame, thus disappearing if the latter is limp. Measurements to gather material parameters for a Biot model of the porous layer have been conducted.The effects of spatial energy decay in the transmission along structures predicted by SEA is studied: a major effect is the increased relevance of indirect coupling loss factors between SEA elements. This may jeopardize the usefulness of SEA at higher frequencies. / <p>QC 20130218</p>

In general, ultra wideband (UWB) signals are transmitted using ~'eIYshort pulses m tiIae domain, thus promising very high data rates. In this thesis, a recei'ler structure is proposed for decoding multiuser information data in a convolutionally coded UWB system. The proposed iterative receiver has three stages: a pulse detector, a symbol detector, and a channel decoder. Each of these stages outputs soft values, which are used as a priori information in the next iteration. Simulation results show that the proposed system can provide performance very close to a single-user system. / Thesis (M.S.)--Wichita State University, College of Engineering, Dept. of Electrical and Computer Engineering. / "July 2006." / Incluldes bibliographic references (leaves 29-31)

This thesis examines the principle of national self-determination as it pertained to the Kurdish population of the Middle East after the First World War and the legacy that it has left behind. The end of the War was characterized by a shift from empires to the European state system. This transition necessitated the redrawing of political borders. As victors of the War, Britain, France, Italy, and the United States of America had the power to influence the future of the continent in terms of creating nation-states. While nation-states were created in Europe, a mandate system was implemented in the Middle East. The Great Powers divided the Middle East into British and French spheres of influence. In so doing, the Kurds were left without a state. This research provides a case study for the Kurds at the close of the First World War and examines the obstacles they face today as the struggle for autonomy continues.

The importance of the Hotelling Valuation Principle (HVP) in economic study lies in its ability to examine and drive the decision of how much of a non-renewable natural resource to produce now versus how much to conserve for future generations - the root of natural resource policy, conservation, regulation, and taxation. Hotelling (1931) assumes that net price (selling price less cost per unit of production) will grow at the discount rate, which in a deterministic setting implies that reserve value is equal to current net price. However, the application of this ideal theory to the oil and gas industry may be difficult.<p>The oil and gas industry is influenced by government regulation, potential monopolistic forces, and well production characteristics - each of which violate the assumptions of Hotellings (1931) basic theory. How these violations affect the HVP is an open question. Most have the effect of limiting current supply, and thus driving prices higher than they would be in a perfectly competitive market. On the other hand, at least in the Canadian context, government regulation tends to increase costs, whereas technological advancement tends to reduce costs. The net result of these effects on future net prices and their discounted value, and therefore the effect on the HVP, is not clear a priori.<p>Another problem relating Hotellings (1931) basic theory to the oil and gas industry lies in the stochastic nature of a firms future net prices and extraction quantities, the product of which gives the firms future cash flows. Correlation between quantity and net price may result from expanding production when prices are high and reducing production when prices are low. Of course such correlation will affect the expected cash flows, and therefore firm value. Or, in other words, the ability to adjust production quantity provides real options for oil and gas firms which may add value.<p>Previous tests of the HVP on oil and gas reserves have utilized data that may contain confounding information that results in unreliable conclusions. The two major deficiencies include using (1) acquisition values, which utilize basin-average rather than firm specific net price data, and (2) conventional oil and gas company market valuations, which incorporate additional management exploration expertise value beyond the reserves value.<p>This study contributes to the literature by providing a more definitive test of the HVP through the use of Canadian oil and gas royalty trusts. These pure play publicly traded entities are focused on production rather than exploration and essentially remediate the deficiencies found in previous literature. Additionally, I include an ancillary variable to proxy real option value and control variables for firm characteristics such as oil weighting (proportion of oil relative to natural gas reserves), reserve quality (proportion of proven producing reserves relative to proven non-producing reserves), and firm size (based on enterprise value). This gives the reader a better understanding of value drivers in the Canadian oil and gas royalty trust sector and how they relate to the HVP.<p>My study generally fails to find support for the HVP. In particular, the results indicate that the HVP overestimates reserve value. This suggests that market participants expect net prices to grow at a rate significantly lower than the fair cost of capital, and production constraints limiting the extraction rate are binding. I do find that the real option proxy explains a significant amount of the difference between the value observed and the value predicted by the HVP. This differs markedly from what previous literature on the HVP applied to market data for the oil and gas industry documents. Each of these papers fails to reject the HVP. The fact that I generally find the value to be lower than that predicted by the HVP is not surprising given the previous literature using market data to test it. Since these studies use conventional oil and gas companies, which likely overvalue reserves because of an exploration premium, finding support for the HVP likely means that royalty trusts will likely correspond to a value lower than that predicted. The difference could account for the exploration premium. On the other hand, when I use the log-linear specification over the second, more volatile sub-sample, I also fail to reject Hotellings theoretical value, which is consistent with previous literature using market data.

Many Chinese commercial banks have experienced ownership transitions during the past decade, along with significant improvements in performance. In order to examine the effect of ownership on bank performance, an empirical study of Chinese commercial banks is performed. A dataset covering 16 Chinese commercial banks over the period of 2002 — 2011 is tested using linear regression model and principle component analysis. It is found that being a Joint-Stock Commercial Bank has a positive effect on earnings per share (EPS), and being a City Commercial Bank increases return on assets (ROA). On the contrary, operating as a Stated-Owned Commercial Bank affects both EPS and ROA negatively. The empirical results also indicate that undergoing initial public offering on the Hong Kong Stock Exchange helps a bank to improve performance, while the listing in Mainland China does not.

We consider an SDE driven by a Lévy noise on a foliated manifold, whose trajectories stay on compact leaves. We determine the effective behavior of the system subject to a small smooth transversal perturbation of positive order epsilon. More precisely, we show that the average of the transversal component of the SDE converges to the solution of a deterministic ODE, according to the average of the perturbing vector field with respect to the invariant measures on the leaves (of the unpertubed system) as epsilon goes to 0. In particular we give upper bounds for the rates of convergence. The main results which are proved for pure jump Lévy processes complement the result by Gargate and Ruffino for Stratonovich SDEs to Lévy driven SDEs of Marcus type.

En este trabajo se examina si de las consideraciones que Donald Davidson ha hecho del caso de la interpretación radical se sigue algo así como una refutación del escepticismo. Se argumenta que tal conclusión no se sigue de las posiciones acerca de la naturaleza del pensamiento y del lenguaje mantenidas por este filósofo americano, ni siquiera con la ayuda del así llamado argumento del intérprete omnisciente. También se rechaza la idea de que concebir su argumentación como un argumento trascendental modesto proporcione mejores resultados antiescépticos. Finalmente se defiende que el mejor modo de articular su posición es como un diagnóstico teórico del escepticismo al estilo del defendido por Michael Williams en su libro Unnatural Doubts. Desde este punto de vista lo que la filosofía davidsoniana haría sería reprochar al escéptico su adhesión al representacionismo y mostrar una alternativa al mismo que explique la posibilidad del pensamiento y del lenguaje. Concebida así la filosofía davidsoniana no constituiría una victoria definitiva ante el escepticismo, sino que más bien mostraría que su posición no es obligatoria y, al menos, garantizaría una presunción de inocencia para nuestras creencias ante el reto del escéptico global. / This work examines whether it follows a refutation of scepticism from Donald Davidson's work on radical interpretation. It is argued that such a conclusion does not follow from Donald Davidson's views on thought and language, not even with the help of the so called omniscient interpreter argument. This work also rejects that such views on language and thought lead to a better result against scepticism when interpreted as a modest transcendental argument. Finally it is claimed that the best way of articulating Davidson's antisceptical strategy is as a theoretical diagnosis of scepticism in a similar vein as Michael Williams has developed in his book Unnatural Doubts. From this point of view what Davidson's philosophy would do is, on the one hand, to reproach the sceptic his adherence to representationism and, on the other hand, to defend an alternative to this philosophical view that explains how thought and language are possible. Conceived of in this way, Davidson's philosophy would not constitute a definitive victory against scepticism. However it would show that scepticism is not compulsory and, at the very least, it would guarantee a presumption of innocence for our beliefs when they face the sceptical threat.

Spray models are increasingly becoming the principal tools in the design and development of gas turbine combustors. Spray modeling requires a knowledge of the liquid atomization process, and the sizes and velocities of subsequently formed droplets as initial conditions. In order to have a better understanding of the liquid atomization process,the breakup characteristics of plane liquid sheets in co-flowing gas streams are investigated by means of linear and nonlinear hydrodynamic instability analyses. The liquid sheet breakup process is studied for initial sinuous and varicose modes of disturbance. It is observed that the sheet breakup occurs at half-wavelength intervals for an initial sinuous disturbance and at full-wavelength intervals for an initial varicose disturbance. It is also found that under certain operating conditions, the breakup process is dictated by the initial varicose disturbance compare to its sinuous counterpart. Further, the breakup process is studied for the combined mode and it is found that the sheet breakup occurs at half- or full-wavelength intervals depending on the proportion of the individual sinuous and varicose disturbances. In general, the breakup length decreases with the increase in the Weber number, gas-to-liquid velocity and density ratios. A predictive model of the initial droplet size and velocity distributions for the subsequently formed spray is also formulated here. The present model incorporates the deterministic aspect of spray formation by calculating the breakup length and the mass-mean diameter and the stochastic aspect by statistical means through the maximum entropy principle based on Bayesian entropy. The two sub-models are coupled together by the various source terms signifying the liquid-gas interaction and a prior distribution based on instability analysis, which provides information regarding the unstable wave elements on the two liquid-gas interfaces. Experimental investigation of the breakup characteristics of the liquid sheet is performed by a high speed CCD camera and the measurement of the initial droplet size and distributions is conducted by phase-Doppler interferometry. Good agreement of the theoretical breakup length with the experiment is obtained for a planar, an annular and a gas turbine nozzle. The predicted initial droplet size and velocity distributions show reasonably satisfactory agreement with experimental data for all the three types of nozzles. Hence this spray model can be utilized to predict the initial droplet size and velocity distributions in sprays, which can then be implemented as a front-end subroutine to the existing computer codes.

Motivated by recent research to automate radiotherapy, this thesis looks into feedback control problems where the feedback sensor imposes considerable time delay. The use of an asymptotic estimator is considered as a method to compensate for the time delay. Properties and parameterizations of asymptotic estimators are analyzed. It is shown that if such a delay compensation scheme is adopted, a separation principle holds, which allows for independent design of the feedback controller and the time delay compensator. The radiotherapy problem is used as a case study to show how asymptotic estimators may be designed, exploiting the separation principle. Lastly, the thesis considers multivariable versions of asymptotic estimators.

In any research program we begin with a hypothesis and when our expected results do not concur with the observed results we must try and understand the dynamics behind the changed process. In this study we were trying to understand the flux between regional groundwater systems, surface waters and sedimentation processes in order to predict the fate of contaminants entering one of the larger bodies of water in the world- Lake Ontario. This lake has increased levels of tritium due to anthropogenic inputs. Our first approach to the problem was to look at tritium fluxes within the system . Hydrological balances were constructed and a series of sediment cores were taken longitudinally and laterally across the lake. The second approach was to quantify the sediment accumulation rate (SAR) within the depositional basins and zones of erosion in order to improve the linkage between erosion control (sedimentation) and the water quality program. In the last chapter the movement of tritium, by molecular diffusion, through the clayey-silts of Lake Ontario is quantified in terms of an effective diffusion coefficient. In these sediments effective diffusion equals molecular diffusion. In a laboratory experiment four cores of lake sediment were spiked with tritium . The resulting concentration gradient changes in the sediment porewaters after six weeks could be modeled by an analytical one- dimensional diffusive transport equation. Results calculated the average lab diffusion coefficient to be 2. 7 x 10 - 5cm 2. sec -1 which is twice that determined by Wang et al, 1952 but still reasonable. Short cores (50 cm) from lake Ontario had observed tritium concentrations with depth that reflected a variable diffusive profile. The increases and decreases in tritium with depth could be correlated between cores. Monthly tritium emission data was obtained and correlations between peaks in the tritium profile and emissions were observed. Monthly variations in release emissions corresponded to approximately a one centimeter slice of core. An average calculated diffusion coefficient of theses cores was 1. 0 x 10 -5 cm 2. sec -1 which compares to Wang's coefficient of 1. 39 x 10 -5 cm 2. sec -1. This implies that tritium is moving through the sediment column at a rate equal to diffusion. The results were obtained for smoothed values. It was not possible to model the perturbations of the data with a one dimensional model. The dynamics of the system imply that tritium could be used as a biomonitor for reactor emissions, mixing time and current direction scenarios and that a better understanding of this process could be gained by future coring studies and a new hypothesis.