This thesis presents an introduction to the design and simulation of a novel class of integrated photonic phased array switch elements. The main objective is to use nano-electromechanical (NEMS) based phase shifters of cascaded under-etched slot nanowires that are compact in size and require a small amount of power to operate them. The structure of the switch elements is organized such that it brings the phase shifting elements to the exterior sides of the photonic circuits. The transition slot couplers, used to interconnect the phase shifters, are designed to enable biasing one of the silicon beams of each phase shifter from an electrode located at the side of the phase shifter. The other silicon beam of each phase shifter is biased through the rest of the silicon structure of the switch element, which is taken as a ground. Phased array switch elements ranging from 2×2 up to 8×8 multiple-inputs/multiple-outputs (MIMO) are conveniently designed within reasonable footprints native to the current fabrication technologies. Chapter one presents the general layout of the various designs of the switch elements and demonstrates their novel features. This demonstration will show how waveguide disturbances in the interconnecting network from conventional switch elements can be avoided by adopting an innovative design. Some possible applications for the designed switch elements of different sizes and topologies are indicated throughout the chapter. Chapter two presents the design of the multimode interference (MMI) couplers used in the switch elements as splitters, combiners and waveguide crossovers. Simulation data and design methodologies for the multimode couplers of interest are detailed in this chapter. Chapter three presents the design and analysis of the NEMS-operated phase shifters. Both simulations and numerical analysis are utilized in the design of a 0º-180º capable NEMS-operated phase shifter. Additionally, the response of some of the designed photonic phased array switch elements is demonstrated in this chapter. An executive summary and conclusions sections are also included in the thesis.

The antigenic variability of the Influenza virus hinders our ability to develop new therapeutic and vaccine strategies which provide a broad protection against all influenza strains. It has been previously suggested that a means to approach this challenge is to identify conserved sequences within viral proteins and use these for future therapeutic targets. Although such conserved sequences are plentiful amongst the internal viral proteins, their lack of exposure to the host immune system makes mounting an immune response against these regions difficult. Alternatively, the surface glycoproteins hemagglutinin (HA) and neuraminidase (NA) have been shown to provide host protection against a limited number of influenza strains when used as vaccine targets; however conserved regions within these proteins which are also antibody accessible are extremely rare. My Ph.D. thesis project is focused on investigating the functional role of a conserved region within the NA protein and to further determine the protection afforded by a monoclonal antibody to this region. In a comprehensive bioinformatics analysis, the only universally conserved sequence amongst all influenza A and B viral NA has been previously identified as being located between amino acids (a.a.) 222-230 (dubbed the HCA-2 region). However, the potential role of this region remains largely unknown. Through an array of experimental approaches including mutagenesis, reverse genetics and growth kinetics, I have found that substitutions in this sequence significantly affect viral replication by impairing the catalytic activity, substrate-binding and thermostability of NA. These findings prompted me to further investigate if antibody to this region may provide protection against influenza infection. Indeed, universal monoclonal antibody (HCA-2 MAb) against this peptide provided broad inhibition against all nine subtypes of NA in vitro and heterosubtypic protection in mice challenged with lethal doses of mouse-adapted viruses. I further demonstrated that residues within this peptide that are exposed on the surface of NA and located in close proximity to the active site, I222 and E227, are indispensable for antibody-mediated inhibition. These data are the first to demonstrate a monoclonal antibody against the NA protein which provides heterosubtypic protection. Since I observed that the HCA-2 antibody provided a broad inhibition against all nine subtypes of influenza A NA, I decided to investigate whether this inhibitory effect could be extended against Influenza B. Here, I have further reported that HCA-2 MAb provides a broad inhibition against various strains of influenza B viruses of both Victoria and Yamagata genetic lineage. I also demonstrate that the growth and NA enzymatic activity of two drug resistant influenza B strains are also inhibited by the HCA-2 antibody. The findings of my Ph.D. thesis project have thus demonstrated that the HCA-2 region is paramount to optimal viral function. Additionally, my data show that antibodies generated against this region provide heterosubtypic protection both in vitro and in vivo and against drug resistant strains. These results indicate that this universally conserved epitope should be further explored as a potential target for future antiviral intervention and vaccine-induced immune responses.

Since their discovery in 1978 by Hill et al. and the development of the transverse holographic technique for their fabrication by Meltz et al. in 1989, fiber Bragg gratings (FBG) have become an important device for applications in optical communications, optical signal processing and fiber-optical sensors. A superstructured fiber Bragg grating (SFBG), also called a sampled fiber Bragg grating, is a special FBG that consists of a several small FBGs placed in close proximity to one another. SFBGs have attracted much attention in recent years with the discovery of techniques allowing the creation of equivalent chirp or equivalent phase shifts. The biggest advantage of an SFBG with equivalent chirp or equivalent phase shifts is the possibility to design and fabricate gratings with greatly varying phase and amplitude responses by adjusting the spatial profile of the superstructure. The realization of SFBGs with equivalent chirp or equivalent phase shifts requires only sub-millimeter precision. This is a relief from the sub-micron precision required by traditional approaches. In this thesis, the mathematical modeling of FBGs and SFBGs is reviewed. The use of SFBGs for various applications in photonic microwave signal processing is considered. Four main topics are presented in this thesis. The first topic is the use of SFBG as a photonic true-time delay (TTD) beamformer for phased array antennas (PAAs). The second topic addresses non-linearities in the group delay response of an SFBG with equivalent chirp in its sampling period. An SFBG with an equivalent chirp using only a linear chirp coefficient may yield a group delay response that deviates from the linear response required by a TTD beamformer. In the thesis, a technique to improve the linearity of the group delay response is proposed and an adaptive algorithm to find the optimal linear and non-linear chirp coefficients to produce the best linear group delay response is described. Since no closed-form solution exists to represent the amplitude and phase responses of an SFBG, we rely on a Fourier transform analogy under a weak grating approximation as a starting point in the design of an SFBG. Simulations are then used to refine the response of the SFBG. The algorithm proposed provides an optimal set of chirp coefficients that minimizes the error in the group delay response. Four gratings are fabricated using the optimized chirp coefficients and their application in a TTD PAA system is discussed. The third topic discusses the use of an SFBG with equivalent phase shifts in its sampling period as a means to realize optical single sideband (SSB) modulation. SSB modulation eliminates the power penalty caused by chromatic dispersion experienced by an optical signal traveling through a long length of optical fiber. By introducing two π phase shifts through equivalent sampling to the SFBG, two ultra-narrow transmission bands are created in the grating stop band of the +/- 1st spectral orders. In the proposed system, a double-sideband plus carrier (DSB+C) modulated optical signal is sent to the input of an optical SSB filter based on the equivalent phase-shift SFBG in order to select the optical carrier and a single sideband, effectively blocking one sideband from propagating. Finally, the fourth topic focuses on the implementation of a photonic microwave bandpass filter based on an SFBG with equivalent chirp. Photonic microwave filters are used to process microwave signals in the optical domain. By using a technique called phase-modulation to intensity-modulation (PM-IM) conversion, a two-tap delay line filter is created with one negative tap. A single SFBG with a chirp in its sampling period is used as a means to achieve the PM-IM conversion for the two taps. Two phase modulated optical carriers are used to generate the two taps, each entering a different port of the SFBG and thus experiencing an opposite dispersion value. The two optical signals are then recombined before being sent to a photodetector (PD) where the filtered microwave signal is recovered.

The goal of this thesis is to improve our understanding of the Greenland ice sheet (GrIS) and how it responds to climate change. This was achieved using ice core records to infer elevation changes of the GrIS during the Holocene (11.7 ka BP to Present). The inferred elevation changes show the response of the ice sheet interior to the Holocene Thermal Maximum (HTM; 9-5 ka BP) when temperatures across Greenland were warmer than present. These ice-core derived thinning curves act as a new set of key constraints on the deglacial history of the GrIS. Furthermore, a calibration was conducted on a three-dimensional thermomechanical ice sheet, glacial isostatic adjustment, and relative sea-level model of GrIS evolution during the most recent deglaciation (21 ka BP to present). The model was data-constrained to a variety of proxy records from paleoclimate archives and present-day observations of ice thickness and extent.

Diabetes mellitus (DM) and hyperglycemia contribute to sympathetic nervous system (SNS) activation and cardiovascular dysfunction. SNS activation and increased norepinephrine levels downregulate cardiac β-adrenergic receptors (β-AR). The ADMIRE-HF trial identified reduced cardiac SNS innervation as an independent prognostic marker in heart failure. The β-AR antagonist [3H]-CGP12177 was used to quantify cardiac β-AR in ex vivo biodistribution studies in streptozotocin (STZ)-treated rats after 8 weeks of sustained hyperglycemia, and in the Zucker Diabetic Fatty (ZDF) rat model of type-2 diabetes at the onset of hyperglycemia (10 weeks of age) and after a sustained period of hyperglycemia (16 weeks of age). In some STZ rats, insulin was provided at the onset of hyperglycemia, or after a sustained period of hyperglycemia. Insulin treatment at both time points prevented reduced [3H]-CGP12177 binding (33-38% compared to controls) observed in STZ hyperglycemics. ZDF β-ARs were intact at 10 weeks but became reduced (16-25% relative to the Zucker leans) following 6 weeks of hyperglycemia. This work supports that cardiac β-AR are reduced in models of DM and that restoring insulin signalling to maintain glycemic control can normalize β-AR density whether provided early or after a period of sustained hyperglycemia.

This study investigated certain aspects of the cross-cultural adaptation process of Afghan returnees who have repatriated from Iran to Afghanistan. The study’s particular focus is the issue of cross-cultural adaptation in the current context of Afghanistan; that is, what challenges face Afghans returning from Iran to their country of origin following years of exile in Iran. Afghan immigration to Iran has a long history. Using Young Yun Kim’s cross-cultural adaptation theory as the leading theoretical framework, the researcher investigated the cultural adaptation of those who have lived in Iran for more than 10 years and have repatriated voluntarily to Afghanistan at least three years before the data for this thesis were gathered. Semi-structured interviews were conducted for collecting primary data from participants for the thesis. Twelve young returnees from Kabul City, aged 18 to 40, volunteered to take part in the interviews. Results revealed that language barriers, cultural knowledge and environmental challenges were some of the dominant difficulties that returnees experienced after their repatriation. Furthermore, the findings showed that the three main strategies used by the young returnees to adapt to their unfamiliar, new environment of Kabul City included social interaction, using mass media, and keeping an open mind on current issues. The findings of the interviews revealed the ongoing changing nature of identity formation of the returnees after their repatriation to Afghanistan and, also the majority of participants (9 out of 12) voiced a strong sense of belonging and attachment to Afghanistan.

Previous research has demonstrated that ingesting fluid of different temperatures results in different whole-body sweat losses (WBSL) and transient changes in local sweat rate (LSR) without any parallel differences in core or skin temperatures. The purpose of this thesis was to determine the potential location and relative contribution of gastrointestinal thermoreceptors that modify sudomotor activity. Eight participants cycled for 75 min while cold (1.5°C) and warm (50°C) water was either swilled in the mouth, or delivered directly to the stomach bypassing the mouth using a nasogastric tube, after 15, 30 and 45-min of exercise. Mouth-swilling warm or cold water did not alter sudomotor output, however delivering warm or cold water directly into the stomach led to a temperature-dependent change in sudomotor output, despite similar core and skin temperatures. These data indicate that thermoreceptors independently modulating sudomotor output probably reside within the abdominal area, but not the mouth.

The Worldwide Interoperability for Microwave Access, or WiMax, is a wireless communication technique based on IEEE 802.16 standards. Its advantage of sending high data rates over long distances, while using a single base station to cover a large area, has made this technique a flexible and reliable solution for public wireless networks. WiMax has two main types of networks: Fixed and Mobile. The most popular transceiver used in WiMax applications is the “Direct-Conversion Architecture” due to its high level of integration and less component requirements, which leads to reduced power dissipation. In Direct Conversion Architecture, the mixer is a key block in the transceiver chain. Depending on design specifications and constraints, different types of mixers may be considered. However, the most appropriate down converter mixer for WiMax applications is the Gilbert-cell mixer. This thesis will then explore the design of a down converter Gilbert-Cell Mixer within the realm of Fixed WiMax technology. This design was achieved in the commercial circuit simulator Advanced Design System (ADS) using the 0.15mm InGaAs pHEMT technology process provided by Win Semiconductor Crop.

In today’s work place where corporations allow employees to use their own smart phones to access their company’s network and sensitive data, it is essential to ensure the security of said data. When an employee smart phone is compromised, companies will rely on the remote wipe command that attempts to remove sensitive data. In this thesis, we analyze the effectiveness of remote wipe commands on the Apple iPhone and Android model devices and demonstrate how data can be recovered following a remote wipe procedure. We conduct two experiments on each device to verify whether remote wipe is a viable defense mechanism or not. Furthermore, we touch on the subject of mobile forensics used by law enforcement and review methods and techniques used to recover data for use as evidence in criminal cases.

The main goal of today’s wireless Service Providers (SPs) is to provide optimum and ubiquitous service for roaming users while maximizing the SPs own monetary profits. The fundamental objective is to support such requirements by providing solutions that are adaptive to varying conditions in highly mobile and heterogeneous, as well as dynamically changing wireless network infrastructures. This can only be achieved through well-designed management systems. Most techniques fail to utilize the knowledge gained from previously tested reconfiguration strategies on system and network behaviour. This dissertation presents a novel framework that automates the cooperation among a number of wireless SPs facing the challenge of meeting strict service demands for a large number of mobile users. The proposed work employs a novel policy-based system configuration model to automate the process of adapting new network policies. The proposed framework relies on the assistance of a real-time simulator that runs as a constant background process in order to continuously find optimal policy configurations for the SPs’ networks. To minimize the computational time needed to find these configurations, a modified tabu-search scheme is proposed. An objective is to efficiently explore the space of network configurations in order to find optimal network decisions and provide a service performance that adheres to contracted service level agreements. This framework also relies on a distributed Quality of Service (QoS) monitoring scheme. The proposed scheme relies on the efficient identification of candidate QoS monitoring users that can efficiently submit QoS related measurements on behalf of their neighbors. These candidate users are chosen according to their devices’ residual power and transmission capabilities and their estimated remaining service lifetime. Service monitoring users are then selected from these candidates using a novel user-to-user semantic similarity matching algorithm. This step ensures that the monitoring users are reporting on behalf of other users that are highly similar to them in terms of their mobility, used services and device profiles. Experimental results demonstrate the significant gains achieved in terms of the reduced traffic overhead and overall consumed users’ devices power while achieving a high monitoring accuracy, adaptation time speedup, base station load balancing, and individual providers’ payoffs.