Mediante técnicas de simulación Montecarlo, prescindiendo de la aproximación de la onda rotante (RWA), se predice la aparición de efectos medibles en los llamados "estados atrapados", rasgo eminentemente cuántico del micromáser o máser monoatómico. / Tesis

by Liang Fa Ming. / Thesis (Ph.D.)--Chinese University of Hong Kong, 1997. / Includes bibliographical references (p. 150-161). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Mode of access: World Wide Web.

Lam Ho-Suen Joffee. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2003. / Includes bibliographical references (leaf 40). / Abstracts in English and Chinese. / Chapter 1 --- Introduction --- p.1 / Chapter 2 --- Review of Mplus --- p.3 / Chapter 3 --- Design of the Simulation Study --- p.6 / Chapter 3.1 --- Simulation Design --- p.6 / Chapter 3.2 --- Covariance Structure Analysis and Mplus Restriction --- p.10 / Chapter 3.3 --- Implementation --- p.10 / Chapter 4 --- Method of Evalution --- p.12 / Chapter 4.1 --- Accuracy of Parameter Estimates --- p.12 / Chapter 4.2 --- Distribution of the Goodness-of-fit Statistic --- p.13 / Chapter 4.3 --- Precision of Standard Errors --- p.14 / Chapter 4.4 --- Number of Replications --- p.15 / Chapter 5 --- Results of the Simulation Study --- p.17 / Chapter 5.1 --- Accuracy of the Parameter Estimates --- p.17 / Chapter 5.2 --- Distribution of the Goodness-of-fit Statistic --- p.18 / Chapter 5.3 --- Precision of the Standard Error --- p.19 / Chapter 5.4 --- Results when the Sample Size is Extremely Large --- p.20 / Chapter 5.5 --- Conclusion --- p.21 / Chapter 6 --- Additional Simulation Study --- p.27 / Chapter 6.1 --- Precision of Standard Error when the Model Consists of Only Con- tinuous and Only Ordinal Variables --- p.28 / Chapter 6.2 --- Comparison of the Simulation Results of Mplus and LISREL --- p.29 / Chapter 6.3 --- Conclusion --- p.31 / Chapter 7 --- Conclusion and Discussion --- p.33 / Chapter A --- Mplus Sample Program (Condition C1 S2 N=500) --- p.36 / Chapter B --- PRELIS Sample Program (Condition C1 S1 N=500) --- p.37

"February 2003" / Bibliography: p. 121-135. / xii, 135 p. : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / This thesis is a theoretical evaluation of the (single) first photon detection (FPD) technique as a limiting case of time-resolved transillumination (TI) for diagnostic purposes. / Thesis (Ph.D.)--University of Adelaide, Dept. of Physics and Mathematical Physics, 2003

The goal of this thesis was to explore the effects of dose resolution, respiratory variation and dose calculation method on dose accuracy. To achieve this, two models of lung were created. The first model, called TISSUE, approximated the connective alveolar tissues of the lung. The second model, called BRANCH, approximated the lungs bronchial, arterial and venous branching networks. Both models were varied to represent the full inhalation, full exhalation and midbreath phases of the respiration cycle.<p> To explore the effects of dose resolution and respiratory variation on dose accuracy, each model was converted into a CT dataset and imported into a Monte Carlo simulation. The resulting dose distributions were compared and contrasted against dose distributions from Monte Carlo simulations which included the explicit model geometries. It was concluded that, regardless of respiratory phase, the exclusion of the connective tissue structures in the CT representation did not significantly effect the accuracy of dose calculations. However, the exclusion of the BRANCH structures resulted in dose underestimations as high as 14\% local to the branching structures. As lung density decreased, the overall dose accuracy marginally decreased.<p> To explore the effects of dose calculation method on dose accuracy, CT representations of the lung models were imported into the Pinnacle$^3$ treatment planning system. Dose distributions were calculated using the collapsed cone convolution method and compared to those derived using the Monte Carlo method. For both lung models, it was concluded that the accuracy of the collapsed cone algorithm decreased with decreasing density. At full inhalation lung density, the collapsed cone algorithm underestimated dose by as much as 15\%. Also, the accuracy of the CCC method decreased with decreasing field size.<p> Further work is needed to determine the source of the discrepancy.

In this thesis we examine methods for measuring entanglement entropy in spin-1/2 Heisenberg systems using quantum Monte Carlo in the valence bond basis. We begin by presenting the quantum Monte Carlo techniques used in this research. We then use these techniques to directly compare the recently proposed valence bond entanglement entropy to the standard definition of entanglement entropy: the von Neumann entanglement entropy. We find that the valence bond entanglement entropy does not give a bound on the von Neumann entanglement entropy, and that it exhibits a multiplicative logarithmic correction to the area law that is not present in the scaling of the von Neumann entanglement entropy. We then present a method to measure higher orders of the generalized Renyi entanglement entropies using valence bond quantum Monte Carlo, and show results for the second Renyi entropy. We find the results converge to the exact results for one dimensional Heisenberg spin-1/2 chains, and see that the scaling of the second Renyi entropy follows an area law in the two dimensional Heisenberg ground state.

The goal of this thesis was to explore the effects of dose resolution, respiratory variation and dose calculation method on dose accuracy. To achieve this, two models of lung were created. The first model, called TISSUE, approximated the connective alveolar tissues of the lung. The second model, called BRANCH, approximated the lungs bronchial, arterial and venous branching networks. Both models were varied to represent the full inhalation, full exhalation and midbreath phases of the respiration cycle.<p> To explore the effects of dose resolution and respiratory variation on dose accuracy, each model was converted into a CT dataset and imported into a Monte Carlo simulation. The resulting dose distributions were compared and contrasted against dose distributions from Monte Carlo simulations which included the explicit model geometries. It was concluded that, regardless of respiratory phase, the exclusion of the connective tissue structures in the CT representation did not significantly effect the accuracy of dose calculations. However, the exclusion of the BRANCH structures resulted in dose underestimations as high as 14\% local to the branching structures. As lung density decreased, the overall dose accuracy marginally decreased.<p> To explore the effects of dose calculation method on dose accuracy, CT representations of the lung models were imported into the Pinnacle$^3$ treatment planning system. Dose distributions were calculated using the collapsed cone convolution method and compared to those derived using the Monte Carlo method. For both lung models, it was concluded that the accuracy of the collapsed cone algorithm decreased with decreasing density. At full inhalation lung density, the collapsed cone algorithm underestimated dose by as much as 15\%. Also, the accuracy of the CCC method decreased with decreasing field size.<p> Further work is needed to determine the source of the discrepancy.

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Computer simulation is now increasingly being used for design and performance evaluation of communication systems. When simulating a mobile wireless channel for communication systems, it is usually assumed that the fading process is a random variate with Rayleigh distribution. The random variates of the fading process should also have other properties, like autocorrelation, spectrum, etc. At present, there are a number of methods to generate the Rayleigh fading process, some of them quite recently proposed. Due to the use of different Rayleigh fading generators, different simulations of the same communication system yield different results. Three methods, viz., the Jakes method, the IDFT method and the filtering WGN method, have been studied, simulated and compared based on the Rayleigh fading process' properties. Various communication systems have been simulated using the Rayleigh fading generators and the difference in the results, if any, have been analyzed. The research studies the different Rayleigh fading generators and compares them using the properties of the Rayleigh fading channel. It is found that the IDFT method and the filtering WGN method generate processes that have properties very close to the ideal Rayleigh fading process.

Thesis (Ph. D.)--University of Washington, 2000. / Vita. Includes bibliographical references (leaves 111-119).