Future generation wireless networks are envisioned to provide ubiquitous networking to a wide number of mobile users, promising them the ability to access the various data networks anywhere and anytime. Such networks have motivated the research into efficient management and allocation of the wireless network's limited resources. Heterogeneity also exists amongst the subscribers, i.e. there are those who are willing to spend a little extra on their subscriptions in the prospect of obtaining a better level of service. This work proposes a framework for efficient resource management, while satisfying the heterogeneous QoS demands of the different subscribers. Part of the proposed framework was used to generate mathematical models for the purpose of analyzing the behavior of the system under two different resource management schemes. / February 2006

The primary objective of this research was to develop and implement a new approach to on-line adaptive radiation therapy (ART) in which daily imaging, plan adaptation and radiation delivery are temporally integrated and performed concurrently. The advantages of this approach are: reduction of treatment time compared to conventional on-line ART; ability to perform a complete plan re-optimization with minimal extension of treatment time; ability to detect and correct for intra-fractional patient motion. This work was motivated by an initial study which compared four radiosurgery techniques. This study was the first quantitative analysis of the correlation between patient anatomy and the quality of treatment plans produced by different radiosurgery techniques. A number of different relationships, both qualitative and quantitative, were discovered between patient anatomy and dosimetric parameters for different techniques. The results were used to successfully predetermine the optimal radiosurgery technique based on patient anatomy. The first step in developing a new approach to on-line ART involved accelerating plan adaptation (re-optimization) using direct aperture optimization (DAO). A series of techniques for adapting the original treatment plan to correct for the deterioration of dose distribution quality caused by the anatomical deformations were investigated. Through modification of the DAO algorithm the optimization search space was reduced and the plan adaptation was significantly accelerated. Next, a new approach to on-line ART was proposed and investigated, in which accelerated plan adaptation and radiation delivery were integrated together and performed concurrently. A fundamental advantage of this approach is that most of the plan re-optimization was performed during radiation delivery, so the time spent adapting the original plan did not significantly increase the overall treatment time. Finally, daily imaging, accelerated plan adaptation and radiation delivery were all temporally integrated using an integrated Linac/Cone Beam CT system. Intra-fractional patient images were used to successfully re-optimize the original treatment plan in near real-time to account for anatomy deformations. This thesis concludes that integration of daily imaging, plan adaptation and radiation delivery for near real-time ART is both feasible and advantageous. With further advances in related technologies, it promises to become a part of clinical practice in the near future.

Fluid dynamics simulations generally require large computational recourses in form of computer power and time. There are different methods for simulating fluid flows that are more or less demanding, but also more or less accurate. Two well known computational methods are the Reynolds Averaged Navier-Stokes (RANS) and Large Eddy Simulation (LES). RANS computes the timeaveraged flow properties, while LES resolve the large structures (eddies) of the flow directly and model the small ones. Hybrid models are combinations of these two models which have been developed to improve the RANS solutions and shorten the simulation time compared to LES computations. One such model is the Scale Adaptive Simulation (SAS) model which uses the RANS model in steady flow regions, such as close to walls, and a LES like model in unsteady regions with large fluctuations. This study was done for evaluating the SAS model compared to Unsteady RANS (URANS) and LES and their performance compared to measurements from an engineering point of view. This was done by running simulations on two different test cases, one external and one internal flow situation. The first one was flow around a wall-mounted cylinder and the second one was flow through an aorta with a coarctation in the descending aorta. The first test case was used to thoroughly evaluate the SAS model by running many simulations with URANS, SAS and LES with different element types, element sizes and flow parameters. The element types that have been analyzed are; tetrahedral, hexahedral and polyhedral. The results were compared with experiments done by Sumner et al. [7, 8, 9, 10]. The second test case was used for evaluating the SAS model even further on another flow situation. For this test case, only two SAS simulations were performed on two different grids; a structured hexahedral and an unstructured polyhedral. These results were compared with Magnetic Resonance Imaging (MRI) measurements obtained from Linköping University. No conclusion of which one of the simulated cases gives the best overall agreement with experimental results could be concluded from the obtained results. The best prediction of the drag coefficient for the cylinder was obtained for the coarsest polyhedral mesh that was run with LES, with the disagreement 0.4 percent. The best prediction of the Strouhal number was obtained for a URANS simulation performed on the coarsest mesh with an improved grid close to the cylinder surface, generating less than one, with a disagreement of 3 percent compared to measurements. For the meshes used, it was found that the polyhedral mesh gave the best overall results and the tetrahedral mesh gave the worst results for the cylinder case. For the aorta case the SAS model produced velocity components that had acceptable agreement with the MRI-measurements, but gave very poor results for the turbulent kinetic energy. The main conclusion of this thesis was that the SAS model performed better than URANS, but took longer time to compute simulations than LES, which was the model that generated the best overall results.

In this dissertation, we discuss an adaptive angular discretization scheme for the neutral-particle transport equation in three dimensions. We mesh the direction domain by dividing the faces of a regular octahedron into equilateral triangles and projecting these onto “spherical triangles” on the surface of the sphere. We choose four quadrature points per triangle, and we define interpolating basis functions that are linear in the direction cosines. The quadrature point’s weight is the integral of the point’s linear discontinuous finite element (LDFE) basis function over its local triangle. Variations in the locations of the four points produce variations in the quadrature set. The new quadrature sets are amenable to local refinement and coarsening, and hence can be used with an adaptive algorithm. If local refinement is requested, we use the LDFE basis functions to build an approximate angular flux, interpolated, by interpolation through the existing four points on a given triangle. We use a transport sweep to find the actual values, calc, at certain test directions in the triangle and compare against interpolated at those directions. If the results are not within a userdefined tolerance, the test directions are added to the quadrature set. The performance of our uniform sets (no local refinement) is dramatically better than that of commonly used sets (level-symmetric (LS), Gauss-Chebyshev (GC) and variants) and comparable to that of the Abu-Shumays Quadruple Range (QR) sets. On simple problems, the QR sets and the new sets exhibit 4th-order convergence in the scalar flux as the directional mesh is refined, whereas the LS and GC sets exhibit 1.5-order and 2nd-order convergence, respectively. On difficult problems (near discontinuities in the direction domain along directions that are not perpendicular to coordinate axes), these convergence orders diminish and the new sets outperform the others. We remark that the new LDFE sets have strictly positive weights and that arbitrarily refined sets can be generated without the numerical difficulties that plague the generation of high-order QR sets. Adapted LDFE sets are more efficient than uniform LDFE sets only in difficult problems. This is due partly to the high accuracy of the uniform sets, partly to basing refinement decisions on purely local information, and partly to the difficulty of mapping among differently refined sets. These results are promising and suggest interesting future work that could lead to more accurate solutions, lower memory requirements, and faster solutions for many transport problems.

In this thesis, we investigate the performance of adaptive loading orthogonal frequency division multiplexing (OFDM) under Nakagami fading with maximal ratio combining (MRC) diversity at receiver. We not only expound the principles and structures of the system, but also analyze its performance of the lower bound on the average capacity under Nakagami fading. First, we defined the lower bound on the average capacity under Nakagami fading with ideal MRC diversity. Then, we fixed the values of bit error rate. A maximum rate adaptive loading strategy is derived for uncoded quadrature-amplitude-modulation modulated OFDM. Simple lower bound expressions are provided for average spectral efficiency of the maximum rate adaptive loading OFDM under Nakagami fading channel. Finally, the numerical results will be also shown.

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The well-known code division multiple access (CDMA) decorrelating detector (DD) and minimum mean-square error (MMSE) detector use a bank of correlators, followed by the inverse of the matrix operation to eliminate the multiple access interference (MAI). However, the operation for the inverse of the matrix involves a great deal of computation, especially when the users¡¦ number is large. Therefore, in this thesis, we propose some recursive methods, the least-mean-square (LMS) algorithm and the recursive least-squares (RLS) algorithm, to detect users¡¦ signals adaptively. We make use of the analogy between a traditional Winner filter and the decorrelating detector to construct adaptive implementation schemes of the decorrelating detector and MMSE detector, called decorrelating transversal filter and MMSE transversal filter, respectively. We applied both LMS algorithm and RLS algorithm to the decorrelating transversal filter and MMSE transversal filter, just as the ways to apply the LMS algorithm and RLS algorithm to the Winner filters. With the proposed schemes, we can greatly reduce the computational complexity of a CDMA multi-user detector while maintaining an acceptable performance.

The need for an effective means of enhancing the science comprehension of elementary teachers brought about changes in the Texas Assessment of Knowledge and Skills (TAKS) exit exam for 5th grade students. The overall goal of this project was to evaluate the effectiveness of an alternative method of science instruction to train pre-service teachers. Web-based instructional designs are emerging as an alternative medium for disseminating course content in continuing education. A need exists to reach a point where web-based materials can be evaluated in terms of achieving desired teaching and learning outcomes, e.g., course grade, professional development certification, skills development and application of course content. The course offered to pre-service teachers provided the opportunity to build their confidence in teaching science and knowledge of subject matter using a combination of traditional and web-based instructional components. The entire course including lessons, exams, and ancillary materials were included in a WebCt distance education platform at Texas A&M University, for pre-service teachers to access online. During the course of the semester students took six exams which determined their overall grade in the course. Study objectives were measured using students enrolled in WFSC 420 Ecology for Teachers during the Fall 2002 and Spring 2003 semesters. The four required assessments were administered before the first exam and after the fifth exam. Analysis of pre- vs. post-course assessments was conducted using paired t-test analysis of mean scores on two assessments including the Science Teaching Efficacy Beliefs Instrument and traditional versus web-based instruction. Student scores on the TAKS test were compared using raw average scores pre- and post-course. Additionally, each student's final course grade was correlated to the final TAKS score to determine the level of score consistency. WFSC 420 Ecology for Teachers prepared pre-service teacher trainees to teach elementary science in two ways. First it provided the relevant science content necessary for teachers to adequately prepare their students for the TAKS exam. Secondly, it has been shown to improve students' confidence in their ability to teach science. Both of these provide a firm foundation to properly educate elementary science teachers for the future.

Gonads are distinct organs in organisms with complicated reproductive systems, and they have specific locations in the body. The gonads of crinoids, however, are scattered in numerous genital pinnules of their arms. We studied seven species of feather stars, Comatella maculata (Carpenter, 1888), Comatella nigra (Carpenter, 1888), Comaster multifidus (M􀎏ller, 1841), Comaster distinctus (Carpenter, 1881), Comanthus parvicirrus (M􀎏ller, 1841), Colobometra perspinosa (Carpenter,1881) and Himerometra magnipinna Clark, 1908 collected at Kenting, southern Taiwan in 2007. The purpose is to explore if the distribution patterns of gonads are adaptative. With bimonthly samplings in a year, it is discovered that the spawning seasons of the species are not synchronized in a particular season. Three models of relationships between maximum arm lengths and numbers of arms exist in the seven species, i.e., constant arm numbers, linear, and quadratic with an asymptote of arm numbers. Therefore, the maximum arm length is more appropriate than arm number as a size index of feather stars. Evidence of bigger mature than immature individuals is found in Comatella maculata, Comaster distinctus and Comaster multifidus, and there is no size difference between males and females. The gonads of feather stars are distributed in the proximal end of arms. The proportion of arms represented by genital pinnules within individuals were constant except in Comanthus parvicirrus where a negative correlation was found. Except the 2 cave-dwelling species, Comatella maculata and Comanthus parvicirrus, most regenerating arms of 5 other species had breakage points occurred near the proximal ends of the arms. Distal breakage may regenerate too fast to recognize. The arms obviously do not grow so fast as to limit gonad development to the proximal ends of arms. Habitat difference may cause variation in genital pinnule widths, but not in the number of genital pinnules as suggested by comparsions of specimens between 2 sites. The cave-dwelling Comanthus parvicirrus has special congregated long arms, which are extended outside. Moreover, these arms have higher probability of breakage, and smaller ranges of genital pinnules than short arms. This phenomenon supports that the limited gonad distribution is adaptive for reducing loss upon arm breakage.

Oyster farming is an important mariculture along the western coast of Taiwan. There is always impacts on the oyster farming. The information of frequency, size and timing of tyhoon every year is strongly connected to the decisions of starting and harvesting of oyster culture. Climate change or variation seem to examine the future management of an oyster farm. This study aims to understand the adaptive strategies of oyster farmers in Tainan to possible climate change or variability. To analyze the mechanism of adaptive capacity and decision-making through a qualitative approach, specially , with focus groups, in-depth interviews, and semi-structured questionnaires. The results revealed abundant adaptation existing in the oyster farmers in Tainan, such as selecting small-size or median-size oyster as a way to cope with typhoon. However information exchange is rare among focus groups and more training and out reach courses are suggested.