As the demand for wireless communication systems grows, the need for spectrum grows accordingly. However, a large portion of the usable spectrum has already been exclusively licensed to various entities. This exclusive allocation method encourages spectrum to be left unused if the licensee has no need for that spectrum. In order to better utilize spectrum and formulate new approaches for greater spectrum use efficiency, it is imperative to possess a thorough understanding about how wireless spectrum behaves over time, frequency, and space. In this thesis, a practical, scalable, and low-cost wideband distributed spectrum sensing system is designed, implemented, and tested. The proposed system is made up of a collection of nodes that use general purpose, off-the-shelf computer hardware as well as a collection of inexpensive software-defined radio (SDR) equipment in order to collect and analyze spectrum data that varies across time, frequency, and space. The spectrum data the proposed system collects is the power present at a given frequency. The tools needed to analyze the gathered data are also created, including a periodogram and spectrogram function, which visualize average spectrum use over a period of time and as spectrum use varies with time, respectively. The proposed system also facilitates the testing of a spatio-spectrum characterization method using real data. This method has only been simulated up to this point. The characterization technique allows for spatially varying spectrum measurements to be visualized using heat maps.

Little is known about the experience of families of children with autism spectrum disorder (ASD) in community settings. The purpose of this research is to learn about the family experience when visiting a science museum, focusing on the motivations of the family, environmental features of the museum, strategies used by family members, and definitions of a successful visit to the museum. Data were collected through semistructured interviews and observations of four families that included a child with ASD. The families in this study appear to want the same community experiences for their children as families with typically developing children. Both the motivations for the visit and features of the environment appeared to influence the family’s approach and strategies they employed for a successful visit. Strategies included those completed before the visit (visitor planning strategies), as well as during the visit (strategies at the museum). The strategies enabled families to enjoy and experience success within the museum environment. The information learned in this study may help families with a child with ASD prepare for and use features of the museum to enjoy successful museum visits. Recommendations are provided for museums seeking to create inclusive opportunities for all families.

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Duan Lei. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2005. / Includes bibliographical references. / Abstracts in English and Chinese. / Abstract --- p.i / Abstract (in Chinese) --- p.iii / Acknowledgement --- p.iv / Table of Contents --- p.v / List of Figures --- p.viii / List of Tables --- p.xii / List of Schemes --- p.xiii / Abbreviations --- p.xvi / Chapter Chapter 1 --- Unsymmetrical Phthalocyanines 一 An Overview / Chapter 1.1 --- Introduction --- p.1 / Chapter 1.2 --- Synthesis of A3B Phthalocyanines --- p.7 / Chapter 1.2.1 --- Statistical Condensation --- p.7 / Chapter 1.2.2 --- The Subphthalocyanine Approach --- p.13 / Chapter 1.2.3 --- Synthesis on Polymer Support --- p.16 / Chapter 1.3 --- Synthesis of A2B2 Phthalocyanines --- p.18 / Chapter 1.3.1 --- Preparation of Cross-Substituted Phthalocyanines (ABAB-type) --- p.19 / Chapter 1.3.2 --- Preparation of ´ب´بAdjacent´ح Phthalocyanines (AABB-type) --- p.21 / Chapter 1.4 --- Objectives of This Thesis --- p.24 / Chapter 1.5 --- References --- p.25 / Chapter Chapter 2 --- "Synthesis, Characterization and in vitro Photodynamic Activities of Mono-Alkoxy and Hydroxy Zinc(II) Phthalocyanines" / Chapter 2.1 --- Introduction --- p.29 / Chapter 2.2 --- "Preparation and Characterization of Unsymmetrical Zinc(II) Phthalocyanines Substituted with a 3,4,5- Tris(dodecyloxy)phenylmethyloxy Group" --- p.30 / Chapter 2.3 --- Preparation and Characterization of Halogenated Unsymmetrical Zinc(II) Phthalocyanines --- p.35 / Chapter 2.4 --- Preparation and Characterization of 2-Hydroxy Zinc(II) Phthalocyanine --- p.44 / Chapter 2.5 --- Introduction of Photodynamic Therapy (PDT) --- p.47 / Chapter 2.6 --- In vitro Photodynamic Activities of 2-Hydroxy Zinc(II) Phthalocyanine --- p.50 / Chapter 2.7 --- Conclusion --- p.52 / Chapter 2.8 --- Experimental Section --- p.52 / Chapter 2.9 --- References --- p.63 / Chapter Chapter 3 --- "Synthesis, Characterization and in vitro Photodynamic Activities of Phthalocyanines Containing N，N-Di- methylaminoethylsulfanyl Substituents" / Chapter 3.1 --- Introduction --- p.66 / Chapter 3.2 --- Preparation and Characterization of Octasubstituted Phthalocyanines --- p.67 / Chapter 3.3 --- Characterization of Disubstituted Amphiphilic Zinc(II) Phthalocyanines --- p.74 / Chapter 3.4 --- In vitro Photodynamic Activities --- p.80 / Chapter 3.5 --- Conclusion --- p.83 / Chapter 3.6 --- References --- p.90

by Guo Wensheng. / Thesis (Ph.D.)--Chinese University of Hong Kong, 1997. / Includes bibliographical references (p. 176-186). / 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.

As the progress of the precision of optical analysis material, Raman spectra is developed as a popular optical and material analysis method. The samples of Raman spectra are low population and prepared easily and fast. Raman spectra would not destroy the samples. GaN is an ideal blue light substrate and a popular nitrogen compound of semi-conductor in III-V group . The character of the GaN is it has a wild direct band gas, high thermal conductivity and high chemical stability. This study is focus on analyzing if there is any difference of the structure of GaN growing on the different substrates. It is compared with photoluminescence spectrum to make sure the accuracy of the result of Raman spectra.

The chronic and severe executive functioning (EF) and self regulation deficits experienced by children with fetal alcohol spectrum disorders (FASD) are well documented and EF and self regulation have been identified as core targets for intervention. The goals of this dissertation were to: (i) examine the effects of a self regulation treatment for children with FASD on a range of EF measures (ii) examine neural markers of treatment outcome and determine if functional magnetic resonance imaging (fMRI) can differentiate treatment responders from nonresponders; (iii) determine if treatment effects generalize to child compliance and qualitatively examine the treatment process. Twenty-five children with FASD participated. Using a wait-list control design children were assigned to an immediate treatment (TXT; n = 12) or delayed treatment control (DTC; n = 13) condition. All children received an evaluation of EF and fMRI at baseline and 12-week follow-up. Parents also completed questionnaires assessing EF and behavior as well as a feedback questionnaire upon completion of treatment. A subset of parents tracked compliance over the course of their child’s therapy. For the TXT group only, parent questionnaires were readministered at 6 month follow-up. At 12-week follow-up, children in the TXT group displayed significant improvements in inhibitory control and social cognition. Additionally, parents reported improved behavioral and emotional regulation. This improvement, along with a further improvement in parent-rated inhibitory control, was maintained at the 6-month follow-up. Neuroplastic changes were also observed as the TXT group showed increased BOLD response in the right prefrontal cortex (PFC) and left caudate on a task of inhibitory control. When treatment responders were compared to nonresponders a pattern of increased BOLD response was found bilaterally in the PFC and left caudate. Compliance tracking revealed that self regulation therapy generalized to improved child compliance at home. Qualitative analysis indicated that perceived clinician competence, caregiver insight about child’s problems and caregiver perceptions of child’s insight about their problems, were the most commonly endorsed themes by caregivers. Results from this research signify that children with FASD are responsive to psychotherapy and following a brief intervention, showed improvements in self regulatory abilities that generalize to other EF areas and parent-reported behaviors.

Opportunistic wireless channel access by non-licensed users has emerged as a promising solution for addressing the bandwidth scarcity challenge. In this thesis, we first design both a deterministic heuristic auction and a randomized auction with a provable performance bound with the guarantee of truthfulness, for networked secondary users. We then turn our attention to mobility support for the secondary users. We introduce two-dimensional bids that reflect a secondary user's willingness to pay for exclusive and nonexclusive channel usage, for the single-channel and multiple-channel scenarios, under which we prove their performances under desired equilibria, respectively. We also devise core-selecting auctions in a combinatorial setting, where secondary users can submit flexible preferences on channels. These auctions can resolve VCG's vulnerability to collusion and shill bidding, and improves seller revenue.

Opportunistic wireless channel access by non-licensed users has emerged as a promising solution for addressing the bandwidth scarcity challenge. In this thesis, we first design both a deterministic heuristic auction and a randomized auction with a provable performance bound with the guarantee of truthfulness, for networked secondary users. We then turn our attention to mobility support for the secondary users. We introduce two-dimensional bids that reflect a secondary user's willingness to pay for exclusive and nonexclusive channel usage, for the single-channel and multiple-channel scenarios, under which we prove their performances under desired equilibria, respectively. We also devise core-selecting auctions in a combinatorial setting, where secondary users can submit flexible preferences on channels. These auctions can resolve VCG's vulnerability to collusion and shill bidding, and improves seller revenue.

This thesis investigates different aspects of spectrum sensing in cognitive radio (CR) technology. First a probabilistic inference approach is presented which models the decision fusion in cooperative sensing as a probabilistic inference problem on a factor graph. This approach allows for modeling and accommodating the uncertainties and correlations in the cooperative sensing system. A constraint in the cognitive radios is the lack of knowledge about the primary signal and channel gain statistics at the secondary users. Therefore, a practical composite hypothesis approach is proposed which does not require any prior knowledge or estimates of these unknown parameters. Detection delay is an important performance measure in spectrum sensing. Quickest detection aiming to minimize detection delay has been studied in other contexts, and we apply it here to spectrum sensing. To combat the destructive channel conditions such as fading, various cooperative schemes based on the cumulative sum (CUSUM) algorithm are considered in this thesis. Furthermore, cooperative quickest sensing with imperfectly known parameters is investigated and a new solution is derived, which does not require any parameter estimation or iterative algorithm. In cognitive radios, there is a fundamental trade-off between the achievable throughput by the CRs and the level of protection for the primary user. In this thesis, this trade-off is formulated for the quickest sensing-based CRs. By throughput analysis, it is shown that for the same protection level to the primary user, the quickest sensing approach results in significantly higher average throughput compared to that of the conventional block sensing approach.