In first part of the study we discuss impact of dynamical core in simulation of tropical rainfall. Over years many new dynamical cores have been developed for atmospheric models to increase efficiency and reduce numerical errors. CAM3.1 gives an opportunity to study the impact of the dynamical core on simulations with its three dynamical cores namely Eulerian spectral(EUL) , Semilagrangian dynamics(SLD) and Finite volume(FV) coupled to a single parametrization package. A past study has compared dynamical cores of CAM3 in terms on tracer transport and has showed advantages using FV in terms of tracer transport. In this study we compare the dynamical cores in climate simulations and at their optimal configuration, which is the intended use of the model. The model is forced with AMIP type SST and rainfall over seasonal, interannual scales is compared. The significant differences in simulation of seasonal mean exist over tropics and over monsoon regions with observations and among dynamical cores. The differences among EUL and SLD, which use spectral transform methods are lesser compared that of with FV clearly indicating role of numerics in differences. There exist major errors in simulation of seasonal cycle in all dynamical cores and errors in simulation of seasonal means over many regions are associated with errors in simulation of seasonal cycle such as over south china sea. Seasonal cycle in FV is weaker compared to SLD and EUL. The dynamical cores exhibit different interannual variability of rainfall over Indian monsoon region, the period of maximum power corresponding to a dynamical core differs substantially with another. From this study there seems no superiority associated with FV dynamical core over all climate scales as seen in tracer transport. The next part of the study deals with impact of diurnal ocean atmosphere coupling in an AGCM,CAM3.1. Due to relatively low magnitude of diurnal cycle of SST and lack of SST observations over diurnal scales current atmospheric models are forced with SSTs of periods grater than a day. CAM 3.1 standalone model is forced with monthly SSTs but the interpolation is linear to every time step between any two months and this linear interpolation implies a linear diurnal and intraseasonal variation of SST which is not true in nature. To test the sensitivity of CAM3.1 to coupling of SST on diurnal scales, we prescribed over tropics(20S20N) a diurnal cycle of SST over daily mean interpolated SST of different magnitudes and phase comparable to observations. This idea of using a diurnal cycle of SST retaining seasonal mean SST in an atmospheric model is novel and provides an interesting frame work to test sensitivity of model to interpolations used in coupling of boundary conditions. Our analysis shows a high impact of using diurnal cycle of SST on simulation of mean rainfall over tropics. The impact in a case where diurnal cycle of SST is fixed and retained to daily mean SST implies that changes associated with a coupled model are to some extent due to change in representation of diurnal cycle of SST. A decrease of excess rainfall over western coast of Bay of Bengal and an increase of rainfall over northern bay of Bengal in such case is similar to the improvement due to coupling atmospheric model to a slab ocean model. This also implies that problems with current AMIP models in simulation of seasonal mean Indian monsoon rainfall could be due to erroneous representation of diurnal cycle of SST in models over this region where the diurnal cycle of SST is high in observations. The high spatial variability of the impact in various cases over tropics implies that a similar spatial variation of diurnal cycle could be important for accurate simulation of rainfall over tropics. Preliminary analysis shows that impact on rainfall was due to changes in moisture convergence. We also hypothesized that diurnal cycle of SST could trigger convection over regions such as northern Bay of Bengal and rainfall convergence feedback sustains it. The impact was also found on simulation of internal interannual variability of rainfall

A simulation scheme is proposed to analyze the effects of elliptic-conical lensed fiber parameters on the coupling efficiency between a 980nm laser diode and single-mode fiber(SMF). The variation of fiber tip shapes with different melting zone volumes was investigated in this thesis. The heat-transfer finite element model in MARC package is employed to simulate the temperature distribution during the melting process. The free convection is considered in predicting the melting zone. Due to the surface tension, a round tip may be solidificated. In this study an elliptical tip lens is expected to improve the coupling efficiency. The microlens shapes with different radius of curvature is simulated with the software of Surface Evolver. The coupling efficiency of 980nm laser source and different elliptic-conical lensed fiber is calculated by utilizing the ZEMAX optical analysis software. The Taguchi method is employed to evaluate the effect of tip shape parameters on the coupling efficiency. The optimal elliptic-conical lensed fiber parameters has also been proposed. The efficiency loss introduced from the misalignments in laser module packaging has also been discussed in this study.

Antibiotics have been extensively used to treat bacterial infections since Alexander Fleming’s discovery of penicillin 1928. Disease causing microbes that have become resistant to antibiotic drug therapy are an increasing public health problem. According to the world health organization (WHO) there are about 440 000 new cases of multidrug-resistant tuberculosis emerging annually, causing at least 150 000 deaths. Consequently there is an immense need to develop new types of compounds with new modes of action for the treatment of bacterial infections. Presented herein is a class of antibacterial ring-fused 2-pyridones, which exhibit inhibitory effects against both the pili assembly system in uropathogenic Escherichia coli (UPEC), named the chaperone usher pathway, as well as polymerization of the major curli subunit protein CsgA, into a functional amyloid fibre. A pilus is an organelle that is vital for the bacteria to adhere to and infect host cells, as well as establish biofilms. Inhibition of the chaperone usher pathway disables the pili assembly machinery, and consequently renders the bacteria avirulent. The focus of this work has been to develop synthetic strategies to more efficiently alter the substitution pattern of the aforementioned ring-fused 2-pyridones. In addition, asymmetric routes to enantiomerically enriched key compounds and routes to compounds containing BODIPY and coumarin fluorophores as tools to study bacterial virulence mechanisms have been developed. Several of the new compounds have successfully been evaluated as antibacterial agents. In parallel with this research, manipulations of the core structure to create new heterocycle based central fragments for applications in medicinal chemistry have also been performed.

The transmitting of video content over Vehicular Ad Hoc Networks (VANETs) faces a great number of challenges caused by strict QoS (Quality of Service) requirements and highly dynamic network topology. In order to tackle these challenges, multipath forwarding schemes can be regarded as potential solutions. However, route coupling effect and the path length growth severely impair the performance of multipath schemes. In this thesis, the current research status about video streaming over VANETs as well as multipath transmissions are reviewed. With the demand to discover a more suitable solution, we propose the Location-Aware Multipath Video Streaming (LIAITHON+) protocol to address video streaming over urban VANETs. LIAITHON+ uses location information to discover relatively short paths with minimal route coupling effect. The performance results have shown it outperforms the underlying single path solution as well as the node-disjoint multipath solution. In addition, the impact of added redundancy on the multipath solution is investigated through LIAITHON+. According to the results, added redundancy has a different impact depending on the data rate.

Fiber tapers have attracted much attention and have been successfully employed in various applications, ranging from resonators, filters, interferometers to sensors. This thesis studies the properties of fiber tapers for the purpose of making tapered-based devices and sensors in aerospace related application where small size and light weight are critical. This thesis includes theoretical derivation and experimental verifications of distributed mode coupling in tapered single-mode fibers (SMFs) with high-resolution optical frequency-domain reflectometry (OFDR) technique. The studies are realized with OFDR through phase detection of a Mach-Zehnder interferometer (MZI), which measures local refractive index change relative to the reference arm. The wavelength shifts converted by the phase change give the group index differences between the fundamental mode and higher-order modes of fiber tapers. The energy re-distribution is observed in Rayleigh backscatter amplitude as a function of fiber length with a ~13µm resolution over the entire fiber taper, and group index difference between core and cladding modes is measured with a spatial resolution of ~2cm by using autocorrelation data processing. The thermal and mechanical properties of fiber tapers have also been characterized with OFDR. The cross-correlation wavelength shift is related to the refractive index change of the modes. It is shown that residual stress induced by the tapering process results in the inhomogeneous thermal property, which can be significantly reduced by an annealing treatment. A fiber taper with a waist diameter of ~6µm has a force sensitivity of ~620.83nm/N, ~500 times higher than that of SMF. Furthermore, polarization-preserving character of tapered polarization-maintaining fibers (PMFs) is evaluated by OFDR-based distributed birefringence along tapered PMFs. Three tapered-based micro-fiber devices have been used as effective mode selecting components to build narrow-linewidth tunable Erbium-doped fiber ring lasers. The fabrication is easy and at a low cost. 1) a tapered fiber tip forms multimode interference mechanism; 2) a two-taper MZI has been demonstrated by splitting/combining the fundamental mode and higher-order modes through fiber tapers and is tuned by bending one taper waist; 3) a novel tunable fiber Fabry-Perot filter, consisting of a hollow-core photonic bandgap fiber and a micro-fiber, is employed in the reflection mode.

The DrrAB proteins of Streptomyces peucetius belong to the ABC family of ubiquitous membrane transporters. The DrrA and DrrB proteins together form a drug efflux pump that carries out the transport of the anticancer drug doxorubicin by carrying out ATP hydrolysis. The present study is the first where the intrinsic factors involved in the assembly of the DrrAB functional complex have been elucidated. The drrA and drrB genes in the wild type operon have overlapping stop and start codons (ATGA) which indicates translational coupling between the two genes. On insertion of a fortuitous stop codon in DrrA it was shown that the expression of DrrB is coupled to that of the upstream gene drrA. Furthermore, it was observed that a functional complex could be achieved only when the genes were maintained in cis in a translationally coupled manner. Translational regulation in DrrA was found to be involved in the control of optimal levels of DrrB. Inhibitory interactions within drrA sequence were speculated to cause translational arrest at the C terminus of DrrA. A novel assembly domain that forms the interface between DrrA containing the Nucleotide Binding Domain (NBD) and DrrB comprising the TransMembrane Domain (TMD) was found. Based on the data presented in this study a model is proposed for the biogenesis of the DrrAB drug pump. The model suggests that translational coupling between DrrA and DrrB is crucial for functional complex formation. Further, there is evidence of regulation of translation by attenuation in the intergenic region of drrA and drrB. The regulation seems to involve the last 30 nucleotides of the mRNA of drrA and some upstream sequences within drrA that cause translational arrest within the C terminus of DrrA. Since DrrB is translationally coupled to drrA, this translational arrest in conjunction with coupling causes lowering in the levels of DrrB. Finally, since the DrrA-DrrB interaction domain lies in the C terminus of DrrA, only the fully translated DrrA product will be competent to form a complex with DrrB. This interaction between the C terminus of DrrA and the N terminus of DrrB may be crucial for initial targeting of the complex to the membrane. The model is expected to serve as primer and open up an interesting yet insufficiently understood subject of membrane protein biogenesis.

Loosely coupled workgroups are common in the real world, and workers in these groups are autonomous and weakly interdependent. They have patterns of work and collaboration that distinguish them from other types of groups, and groupware systems that are designed to support loose coupling must address these differences. However, they have not been studied in detail in Computer-Supported Cooperative Work (CSCW), and the design process for these groups is currently underspecified. This forces designers to start from scratch each time they develop a system for loosely coupled groups, and they must approach new work settings with little information about how work practices are organized. <br><br> In this dissertation, I present a design framework to improve the groupware design process for loosely coupled workgroups. The framework has three main parts that add a new layer of support to each of the three stages in the general groupware design process: data collection about the target work setting, analysis of the data, and system design based on the analysis results. The framework was developed to provide designers with support during each of these stages so that they can consider important characteristics of loosely coupled work practice while carrying out design for the target group. The design framework is based on information from CSCW and organizational research, and on real-world design experiences with one type of loosely coupled workgrouphome care treatment teams. <br><br> The framework was evaluated using observations, interviews, and field trials that were carried out with multidisciplinary home care treatment teams in Saskatoon Health Region. A series of field observations and interviews were carried out with team members from each of the home care disciplines. The framework was then used to develop Mohoc, a groupware system that supports work in home care. Two field trials were carried out where the system was used by teams to support their daily activities. Results were analyzed to determine how well each part of the design framework performed in the design process. The results suggest that the framework was able to fill its role in specializing the general CSCW design process for loosely coupled groups by adding consideration for work and collaboration patterns that are seen in loosely coupled settings. However, further research is needed to determine whether these findings generalize to other loosely coupled workgroups.

In an attempt to provide a more secure and amiable living environment in our homes, there has been constant effort to develop more efficient and suitable intelligent sensor technology for household application. Wireless sensors provide an efficient means of sensing without the need for messy wiring, and are ideally suited for the household environment. Although many sensor products have been developed (e.g. temperature, humidity and smoke), automated detection and reporting of an incidence occurring in places hard to observe or reach, such as wetting of diapers or water seepage under carpets, are still not readily available at low cost. Most of the existing technologies consist of complex design architecture and follow specific communication protocols which can be overkill for many simple household applications. In this thesis, we present a new wireless sensor system which is based on the detection of just the ON or OFF state of a condition. This approach overcomes the need for complex architecture and design, but is still able to achieve the functionality that is required for many household applications such as water leakage, food rotting, diaper wetting etc. and thus can be made available very cheaply. The sensor system consisting of an interrogator and a sensor circuit is implemented using inductive coupling. A passive L-C circuit is used for the sensor design and the system is tested using diaper wetting as an example of a simple household application. The testing results shows that the sensor can detect an ON and OFF condition for sensor and tag separation of 10 cm which is enough for applications like water leakage behind walls and under carpets, diaper wetting, food rotting etc.

L'acoblament de soroll a través del substrat en circuits integrats mixtos és un important problema que sovint limita les prestacions de la circuiteria analògica. Les característiques d'aquest tipus d'acoblament i els factors que en determinen la importància no són ben compresos, així que calen criteris per tal de triar les millor accions per a resoldre el problema. En els darrers anys s'han proposat algunes tècniques per reduir el soroll de substrat, tot i que no hi ha una idea clara de l'abast de la seva validesa, i de les condicions que calen per a la seva eficàcia. La majoria de l'esforç de recerca que s'ha dedicat a aquest tema s'ha centrat en el desenvolupament de models, que permetin la incorporació del substrat en les eines CAD que s'utilitzen en les fases de simulació dels dissenys. Per tant, aquests resultats de recerca no contribueixen a la comprensió dels aspectes rellevants de l'acoblament.En aquesta tesi doctoral s'ha realitzat un estudi analític i experimental que ha permès determinar les característiques tecnolòiques i de disseny que faciliten l'acoblament vers la circuiteria analògica. S'ha partit d'una caracterització de l'acoblament mitjançant un simulador de dispositius, on s'ha pogut comprovar la importància d'aspectes com el tipus de substrat, la velocitat de commutació dels dispositius, les seves dimensions, o el punt de polarització. La caracterització s'ha realitzat tant per tecnologies CMOS com BiCMOS, i ha estat completada amb mesures sobre estructures de test. Posteriorment s'ha portat a terme un anàlisi de la propagació del soroll en el substrat, amb el que s'han esbrinat les característiques tecnològiques i de polartizació que determinen l'atenuació del soroll. L'anàlisis'ha realizat suposant condicions de polarització ideals, i ha permès determinar el potencial d'algunes mesures per a la minimització de l'acoblament. A continuació s'ha fet una revisió de les diverses tècniques de modelació del substrat, i utilitzant algun dels models s'han pogut realitzar simulacions circuitals per a estudiar l'acoblament en circuits de dimensions realistes, tenint en compte factors com els elements paràsits dels terminals de l'encapsulat, la influència dels pads, o l'estratègia de polarització. Aquest estudi s'ha complementat amb el disseny d'un circuit mixte de test sobre el que s'han fet mesures per a verificar els resultats obtinguts, i corroborar els mecanismes que determinen l'acoblament. La tesi s'ha completat amb una revisió de l'eficàcia d'algunes tècniques específiques per a la reducció del soroll, i amb un estudi de l'evolució en tecnologies futures tant del soroll de commutació a les línies d'alimentació, com del soroll acoblat a través del substrat. / El acoplo de perturbaciones a través del sustrato de silicio en circuitos integrados mixtos representa un importante problema que a menudo limita las prestaciones de la circuiteria analógica. Hay una cierta incomprensión de las características del acoplo i de los factotres que que determinan su importancia, de forma que faltan criterios para implementar técnicas que reduzcan el problema. En los últimos años se han propuesto diversas técnicas para la reducción del ruido de sustrato, aunque no estan claros su rango de validez y las condiciones que se deben cumplir para su eficacia. La mayor parte del esfuerzo investigador realizado en este campo se ha centrado en el desarrollo de modelos que faciliten la incorporación del sustrato a las herramientas CAD utilizadas en la fase de simulación de un circuito. Por tanto, esta investigación no ofrece aportaciones en la comprensión de los aspectos relevantes del fenómeno.En esta tesis doctoral se ha realilzado un estudio analítico y experimental que ha permitido determinar las características tecnológicas y de diseño que facilitan el acoplo sobre la circuitería analógica. Se ha partido de una caracterización del acoplamiento mediante un simulador de dispositivos, donde se ha podido comprovar la importancia de aspectos como el tipo de sustrato, la velocidad de conmutación de los dispositivos, sus dimensiones, o el punto de polarización. La caracterización se ha realizado tanto para estructuras CMOS como BiCMOS, y ha sido completada con medidas sobre estructuras de test. Posteriomente se ha llevado a cabo un análisis de la propagación del ruido en el sustrato, con el que se han determinado las características tecnológicas y de polarización que determinan la atenuación del ruido. El análisis se ha realizado suponiendo condiciones de polarización ideales, y ha permitido determinar el potencial de algunas medidas para la minimización del acoplo. A continuación se ha realizado una revisión de las diversas técnicas de modelación del sustrato, y utilizando alguno de los modelos se han podido realizar simulaciones circuitales para estudiar el acoplo en circuitos de dimensiones realistas, teniendo en cuenta factores como los elementos parásitos de los terminales del encapsulado, la influencia de los pads, o la estrategia de polarización. Este estudio se ha complementado con el diseño de un circuito mixto de test sobre el que se han hecho medidas para verificar los resultados obtenidos, y corroborar los mecanismos que determinan el acoplo. La tesi se ha completado con una revisión de la eficacia de algunas técnicas específicas para la reducción del ruido, y con un estudio de la evolución en tecnologías futuras tanto del ruido de conmutación a través de las líneas de alimentación, como del ruido acoplado a través del sustrato. / Noise coupling through common silicon substrate in mixed-signal circuits is an important problem that often limits the performance of the analog circuitry. The characteristics of this type of coupling and the factors determining its importance are not well understood, so criteria to choose the best actions to solve the problem are needed. Several techniques to reduce substrate noise have been proposed in the last years, although there is no clear idea about their range of validity, and the conditions required for their efficacy. Most of the research effort done in this field has been centered on the development of models, in order to allow the incorporation of substrate in the CAD tools used in simulation design stages. Thus, these research results do not contribute to the understanding of the relevant aspects of coupling.In this thesis an analytic and experimental study has been done, which has allowed determining the technological and design characteristics relevant in the coupling. The study has started with a characterisation of coupling using a device simulator, which has allowed determining the importance of aspects such as substrate type, device switching speed, device dimensions, or their biasing. Characterisation has been done both for CMOS and BiCMOS technologies, and it has been completed with measurements on test structures. Next an analysis of noise propagation through the substrate has been carried out, which has allowed to find out the biasing and technological characteristics that determine noise attenuation. The analysis has been done assuming ideal biasing conditions, and the potentiality of some noise minimisation measures could be determined. Next a review of the different substrate modelling techniques has been done, and some of the models have been used to perform circuit simulations to study coupling in circuits of some complexity, taking into account factors such as package pins parasitics, the influence of the ring of pads, or the biasing strategy. This study has been complemented with the design and measurements of a mixed-signal test circuit, which allowed verification of the results previously obtained, and the coupling mechanism. Finally the thesis is completed with a review of the efficacy of noise-reducing specific techniques, and with the study of the trends of switching noise on power supply lines and substrate for near future technologies.

Microwave tomography is a classical approach for non destructive evaluation. Microwave tomography has many biomedical applications such as brain imaging, temperature sensing in different biological tissues and breast cancer detection. In a microwave tomography system, numbers of radiators are used to transmit microwave signal into an object under test and the scattered fields are recorded. The collected data is used to quantitatively reconstruct the dielectric profiles of the object under test through inverse scattering mechanism. It has been shown that by using wide band data, highly stable and high resolution reconstructions can be obtained. Lower frequency components provide stability of the reconstructions, while higher frequency components contribute to the resolution.  Accordingly, ultra wideband antennas are required in UWB microwave tomography systems. In addition to ultra wide bandwidth, the antennas in a microwave tomography system should be easy to model with computational program. In this thesis Printed elliptical monopole antenna (PEMA) is investigated for microwave tomography. It is a multi resonant antenna with simple structure and yield ultra wide bandwidth. The performances of a single antenna and an antenna array are studied. The reflection coefficients of the antenna, mutual coupling between antennas and energy distribution in the near field are obtained by means of simulations in CST microwave studio.    The simulation result shows that reflection coefficients of the designed antenna are below         -10dB over the entire frequency band of interest (1-4.5GHz), mutual coupling between antennas at different locations are below -20dB over the entire frequency band of interest and the designed antenna also has good electric field distribution in an array configuration which makes the radiated power concentrating in the imaging region. These results indicate that PEMA is a potential antenna for microwave tomography applications.