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Cognitive radio refers to the technology that the devices can intelligently access unused frequency resources which are originally reserved for legacy services in order to increase the spectrum utilization. At the mean time, the legacy services should not be affected by the access of cognitive radio devices. The common problems in cognitive radio are how to find unused frequency resources (spectrum sensing) and how to access them (spectrum accessing). This dissertation focuses on the robust methods of spectrum sensing as well as spectrum accessing strategies with the statistics of channel availabilities. The first part of the thesis studies non-parametric robust hypothesis testing problem to eliminate the effect of the uncertainty and instability introduced by non-stationary noise, which is constantly observed in communication systems. An empirical likelihood ratio test with density function constraints is proposed. This test outperforms many popular goodness-of-fit tests, including the robust Kolmogorov-Smirnov test and the Cramér-von Mises test, etc. Examples using spectrum sensing data with real-world noise samples are provided to show their performance. The second part focuses on channel idle time distribution based spectrum accessing strategies. Through the study of the real-world wireless local area network traffic, it is identified that the channel idle time distribution can be modeled using hyper-exponential distribution. With this model, the performance of a single cognitive radio, or the secondary user, is studied when the licensed user, or the primary user, does not react to interference. It is also shown that with the complete information of the hyper-exponential distribution, the secondary user can achieve a desirable performance. But when the model exhibits uncertainty and time non-stationarity, which would happen for any kind of wireless traffic, the secondary user suffers from huge performance loss. A strategy that is robust to the uncertainty is proposed. The performance of this strategy is demonstrated using experimental data. Another aspect of the problem is when the PU is reactive. In this case, a spectrum accessing strategy is devised to avoid large-duration interference to the PU. Additionally, the spectrum accessing strategies are also extended to the cognitive radio networks with multiple secondary users. A decentralized MAC protocol is devised which reaches a total secondary capacity performance close to the optimal. A discussion of the engineering aspects with practical consideration of spectrum sensing and accessing is given at the end. / text

This ethnographical study provides a better understanding into the daily lives of adults with Fetal Alcohol Spectrum Disorder (FASD), it demonstrates how mentorship can increase their quality of life and finally it provides recommendations on how to best support them. FASD is a life-long disability that diminishes a persons cognitive and adaptive functioning. In this study, adults with FASD and their mentors were interviewed at the CUMFI (Central Urban Métis Federation Inc.) Wellness Centre, a mentorship program for individuals with cognitive disabilities in Saskatoon, Saskatchewan to determine the adults need for support, what supports were received, how effective that support was and how to improve the support. This research was approached through critical ethnography and the result is a call for social change to help individuals with FASD. The CUMFI Wellness Centre is an effective mentorship model that could be used to design other mentorship programs for adults with FASD across the country. In this study, it was determined that the adults with FASD involved in the mentorship program at the CUMFI Wellness Centre had increased self-esteem and a better quality of life. Mentorship can help adults with FASD to find housing, buy groceries, receive community supports and maintain a healthy lifestyle which will help them function better in society. Support and mentorship provides safeguards to decrease the likelihood of adults with FASD ending up on the streets, in jails, hospitals and treatment centers. We must respond to the needs of these individuals and their families and provide supports for them. It is ethical that we do so as these individuals were not responsible for their cognitive disability from the prenatal alcohol to which they were exposed. It is practical and cost-effective to assist this population so that they can healthy and productive members of our society.

This ethnographical study provides a better understanding into the daily lives of adults with Fetal Alcohol Spectrum Disorder (FASD), it demonstrates how mentorship can increase their quality of life and finally it provides recommendations on how to best support them. FASD is a life-long disability that diminishes a persons cognitive and adaptive functioning. In this study, adults with FASD and their mentors were interviewed at the CUMFI (Central Urban Métis Federation Inc.) Wellness Centre, a mentorship program for individuals with cognitive disabilities in Saskatoon, Saskatchewan to determine the adults need for support, what supports were received, how effective that support was and how to improve the support. This research was approached through critical ethnography and the result is a call for social change to help individuals with FASD. The CUMFI Wellness Centre is an effective mentorship model that could be used to design other mentorship programs for adults with FASD across the country. In this study, it was determined that the adults with FASD involved in the mentorship program at the CUMFI Wellness Centre had increased self-esteem and a better quality of life. Mentorship can help adults with FASD to find housing, buy groceries, receive community supports and maintain a healthy lifestyle which will help them function better in society. Support and mentorship provides safeguards to decrease the likelihood of adults with FASD ending up on the streets, in jails, hospitals and treatment centers. We must respond to the needs of these individuals and their families and provide supports for them. It is ethical that we do so as these individuals were not responsible for their cognitive disability from the prenatal alcohol to which they were exposed. It is practical and cost-effective to assist this population so that they can healthy and productive members of our society.

Multicarrier modulation is a transmission technique that is quite convenient for high data rates in wireless communication. Information symbols are partitioned and parallelly sent over multiple narrowband subchannels. Pulse shaping filters are critically important in multicarrier modulation for determining the characteristics of signal in time and frequency domains. In this thesis, we propose a new pulse shaping approach for multicarrier schemes to increase spectral efficiency in multi-user scenarios. Conventionally, the time-frequency lattice and the prototype filter are designed considering the worst-case of time-varying multipath channel. However, this approach ignores to make use of multi-user diversity and leads to excessive spacings between successive symbols in time and frequency. Unlike the prevalent methods, we investigate user-based filter utilization considering the wireless channel of each user individually to prevent over-design and improve spectral efficiency. Also, this approach is implemented in a denser time-frequency lattice design. Symbols are allowed to be overlapped (depending on time-frequency dispersion of their individual channels) as long as the signal-to-interference ratios (SIRs) observed by all users are kept above a certain level. Employing user-specific filters to enhance SIR of the user exposed to the most interference provides more overlapping flexibility. Therefore, further improvement in spectral efficiency is achieved in our wireless communication system design.

In recent years, mental illness in pregnant and postpartum women has become a public health concern. Untreated and undertreated maternal mental illness has a significant negative impact on not only the mother, but also on the baby and family. Further, many women do not seek help or access mental health care due to stigma surrounding mental illness, the unrealistic social expectations of motherhood, and the fear of being judged or rejected. An interpretive descriptive study informed by a feminist perspective was conducted with six postpartum women who sought maternal mental health care services. Semi-structured interviews provided an opportunity to explore women’s experiences of having a maternal mental illness, accessing care, and the role of stigma. Analysis focused on the bio-psycho-social dimensions of their experiences. A shared experience and meaning emerged: self stigma and expectations of motherhood, stigma and infertility, factors influencing self stigma, level of self-efficacy, and treatment satisfaction, engagement and outcome. Findings are discussed with reference to the current literature on maternal mental illness, stigma, and infertility. Findings are conceptualized using Brown’s (2006) Shame Resilience Theory, implications for practice are presented including women’s advice to other women, and recommendations for future research are made.

Dynamic Cellular Cognitive System (DCCS) serves as a cognitive network for white space devices in TV white space. It is also designed to provide quality communications for first responders in area with damaged wireless communication infrastructure. In DCCS network, diverse types of communication devices interoperate, communicate, and cooperate with high spectrum efficiency in a Dynamic Spectrum Access (DSA) scenario. DCCS can expand to a broad geographical distribution via linking to existing infrastructure. DCCS can quickly form a network to accommodate a diverse set of devices in natural disaster areas. It can also recover the infrastructure in a blind spot, for example, a subway or mountain area. Its portability and low cost make it feasible for commercial applications. This dissertation starts with an overview of DCCS network. DCCS defines a cognitive radio network and a set of protocols that each cognitive radio node inside the network must adopt to function as a user within the group. Multiple secondary users cooperate based on a fair and efficient scheme without losing the flexibility and self adaptation features. The basic unit of DCCS is a cell. A set of protocols and algorithms are defined to meet the communication requirement for intra-cell communications. DCCS includes multiple layers and multiple protocols. This dissertation gives a comprehensive description and analysis of building a DCCS network. It covers the network architecture, physical and Medium Access Control (MAC) layers for data and command transmission, spectrum management in DSA scenario, signal classification and synchronization and describes a working prototype of DCCS. Two key technologies of intra-cell communication are spectrum management and Universal Classification and Synchronization (UCS). A channel allocation algorithm based on calculating the throughput of an available is designed and the performance is analyzed. UCS is conceived as a self-contained system which can detect, classify, and synchronize with a received signal and extract all parameters needed for physical layer demodulation. It enables the accommodation of non-cognitive devices and improves communication quality by allowing a cognitive receiver to track physical layer changes at the transmitter. Inter-cell communications are the backhaul connections of DCCS. This dissertation discusses two approaches to obtaining spectrum for inter-cell communications. A temporary leasing approach focuses on the policy aspects, and the other approach is based on using OFDMA to combine separate narrowband channels into a wideband channel that can meet the inter-cell communications throughput requirements. A prototype of DCCS implemented on GNU radio and USRP platform is included in the dissertation. It serves as the proof of concept of DCCS. / Ph. D.

A precaução com riscos e prejuízos na utilização de instrumentos de pesquisa interacionais, tais como questionários e entrevistas, ainda é muito pequena, visto que, a maioria dos pesquisadores entende que riscos são possibilidades de danos ou agressões ao corpo físico, esquecendo-se que a presença de riscos de ordem moral, emocional ou espiritual pode ocasionar aos participantes da pesquisa prejuízos e, até mesmo, danos a sua saúde mental. Segundo o princípio da não-maleficência proposto por Beauchamp e Childress, o pesquisador tem a obrigação de não infligir danos ou males intencionalmente. Dentro desta perspectiva, uma análise acurada de tais instrumentos de pesquisa deve ser feita, avaliando-se a relação riscos/benefícios. Deve-se também se considerar as precauções quando da inclusão de indivíduos pertencentes a grupos vulneráveis, já que os mesmos apresentam uma maior predisposição a sofrer danos. Estes só poderão ser incluídos na pesquisa se a sua participação for essencial à hipótese que está sendo testada. Um levantamento realizado com protocolos de pesquisa encaminhados a um Comitê de Ética em Pesquisa (CEP), verificou que uma grande parte dos pesquisadores (14; 15,2%) descreveram os riscos de suas pesquisas com questionário ou entrevista, como inexistentes, devido ao fato de se tratar ?apenas de questionamentos?. Contudo, tais instrumentos podem ser tão evasivos e repletos de riscos quanto às experimentações que envolvem o corpo físico. Deste modo, chama-se a atenção para o fato de que a falta de uma análise crítica e uma descrição dos riscos pelo pesquisador pode acarretar a ausência de medidas a serem utilizadas para evitá-los ou minimizá-los, e, até mesmo, a previsão de uma assistência especializada, caso venham a ocorrer. Palavras chave: bioética; ética em pesquisa; risco; redução do dano; método; coleta de dados. / Precaution with risks and damages in the use of interactive research instruments, such as questionnaires and interviews, is still very small, since a majority of researchers understand that risks are possibilities of damage or aggression to the physical body and forget that the presence of moral, emotional or spiritual risks can cause damage to research participants and even damages to their mental health.. According to the nonmaleficence principle proposed by Beauchamp & Childress, researchers are obliged not to cause any intentional harm or damage. Thus, a comprehensive analysis of such instruments of research must be made, evaluating the relation between its risks and benefits. Additional precaution must be considered if vulnerable individuals are to be included in the research, since they are more predisposed to suffer damage. Such individuals could only be included in the research if their participation is essential to the hypothesis that is being tested. A survey carried out using protocols of research that were directed to a Committee of Ethics in Research (CER) verified that a great part of researchers (14; 15.2%) that used questionnaires or interviews in their works hadn?t described any risks in this practice, and if so they were considered ?only questionings\". However, such instruments can be as invasive and full of risks as the experiments involving the physical body. For this reason, we think it?s important to focus on the fact that the lack of a critical analysis and description of the risks by the researcher can cause the absence of measures necessary to prevent them or to minimize them, and, even the forecast of a specialized assistance, in case they occur.

Availability of historical unit cost data is an important factor in developing accurate project cost estimates. State highway agencies (SHAs) collect data on historical bids and/or production rates, crew sizes and mixes, material costs, and equipment costs, including contractor overhead and profit. The objective of this research is to create a framework to define a standardized and a systematic approach for developing unit costs for construction project estimating. A literature review was conducted that provided an overview of estimating techniques used in project estimating, estimation guidelines maintained by SHAs, and information systems used in the estimation process. After gaining a broad overview of the industry‘s approach to unit cost development, a survey was then conducted. The purpose of the survey was to identify the state of practice in SHAs for unit cost development. The survey helped to identify SHAs doing considerable work in unit cost development and interviews were conducted with these agencies to know their unit cost development process in detail. The results from survey and the interviews were then used in defining the framework. The framework provides a standardized way to use historical data for preparing construction project estimates.

A precaução com riscos e prejuízos na utilização de instrumentos de pesquisa interacionais, tais como questionários e entrevistas, ainda é muito pequena, visto que, a maioria dos pesquisadores entende que riscos são possibilidades de danos ou agressões ao corpo físico, esquecendo-se que a presença de riscos de ordem moral, emocional ou espiritual pode ocasionar aos participantes da pesquisa prejuízos e, até mesmo, danos a sua saúde mental. Segundo o princípio da não-maleficência proposto por Beauchamp e Childress, o pesquisador tem a obrigação de não infligir danos ou males intencionalmente. Dentro desta perspectiva, uma análise acurada de tais instrumentos de pesquisa deve ser feita, avaliando-se a relação riscos/benefícios. Deve-se também se considerar as precauções quando da inclusão de indivíduos pertencentes a grupos vulneráveis, já que os mesmos apresentam uma maior predisposição a sofrer danos. Estes só poderão ser incluídos na pesquisa se a sua participação for essencial à hipótese que está sendo testada. Um levantamento realizado com protocolos de pesquisa encaminhados a um Comitê de Ética em Pesquisa (CEP), verificou que uma grande parte dos pesquisadores (14; 15,2%) descreveram os riscos de suas pesquisas com questionário ou entrevista, como inexistentes, devido ao fato de se tratar ?apenas de questionamentos?. Contudo, tais instrumentos podem ser tão evasivos e repletos de riscos quanto às experimentações que envolvem o corpo físico. Deste modo, chama-se a atenção para o fato de que a falta de uma análise crítica e uma descrição dos riscos pelo pesquisador pode acarretar a ausência de medidas a serem utilizadas para evitá-los ou minimizá-los, e, até mesmo, a previsão de uma assistência especializada, caso venham a ocorrer. Palavras chave: bioética; ética em pesquisa; risco; redução do dano; método; coleta de dados. / Precaution with risks and damages in the use of interactive research instruments, such as questionnaires and interviews, is still very small, since a majority of researchers understand that risks are possibilities of damage or aggression to the physical body and forget that the presence of moral, emotional or spiritual risks can cause damage to research participants and even damages to their mental health.. According to the nonmaleficence principle proposed by Beauchamp & Childress, researchers are obliged not to cause any intentional harm or damage. Thus, a comprehensive analysis of such instruments of research must be made, evaluating the relation between its risks and benefits. Additional precaution must be considered if vulnerable individuals are to be included in the research, since they are more predisposed to suffer damage. Such individuals could only be included in the research if their participation is essential to the hypothesis that is being tested. A survey carried out using protocols of research that were directed to a Committee of Ethics in Research (CER) verified that a great part of researchers (14; 15.2%) that used questionnaires or interviews in their works hadn?t described any risks in this practice, and if so they were considered ?only questionings\". However, such instruments can be as invasive and full of risks as the experiments involving the physical body. For this reason, we think it?s important to focus on the fact that the lack of a critical analysis and description of the risks by the researcher can cause the absence of measures necessary to prevent them or to minimize them, and, even the forecast of a specialized assistance, in case they occur.