Characterizing nonlinearity in multiantenna multibeam transmitters

Abstract. In this thesis, effects of power amplifier (PA) distortion in multiantenna transmitter is studied. Input signal of each PA in the array is modelled by two or multiple tones to characterize the nonlinearity in terms of intermodulation distortion (IMD). In intermodulation, the phase of the nonlinearity depends on the phases of the corresponding input tones. Hence, in beamforming, progressive phase of the nonlinear components over the antenna elements creates a steered beam for the nonlinearity. Measurement setup is created to measure the phase and amplitude of the IMD components in the PA output. The theoretical polynomial relation of the IMD phase dependency on the input tones is validated by measurements. For flexible measurements, the setup is automatized by standard commands for programmable instruments. Second part of the thesis studies the array IMD by simulations in MATLAB. The used PA model is a memoryless polynomial fitted against the measured amplitude-to-amplitude modulation and amplitude-to-phase modulation responses of a real amplifier. The effects of nonlinearity are studied by using two tones to present each independent data stream in the PA inputs. Hence, in multibeam scenario, each data stream is modelled by two tones having individual phase and amplitude depending on the beamforming coefficients of given stream. The simulations are performed in frequency domain by utilizing the concept of spectral convolution to model the intermodulation distortion, and array factor to model the far-field radiation of the linear and nonlinear PA output components. By utilizing the simulator, PA nonlinearity is analyzed in single-beam and multi-beam scenarios by varying the steering angles, allocated stream powers and amplitude distribution over the PAs. It is observed that IMD terms which depend on only one stream are steered to same direction as the linear terms whereas the IMD terms depending on both streams spreads more in space. This has potentially positive impacts on the signal-to-distortion ratio of the streams observed in beamforming directions

Lumbar morphometry: A study of lumbar vertebrae from a Pakistani population using computed tomography scans

Study design: A cross-sectional study.Purpose: To describe the characteristics of lumbar vertebrae of Pakistani patients reporting at a tertiary care hospital and compare with studies from other populations.Overview of literature: Several studies have been conducted to determine morphometry of lumbar vertebrae. Most of the studies involve Caucasian populations, still data on other populations still sparse. This is the first study describing lumbar morphometry of a Pakistani population.Methods: An observational study was conducted based on a review of thin-cut (3 mm) computed topographic images of lumbar vertebrae. Two-hundred and twenty vertebrae from forty-nine patients were studied, and various dimensions were analyzed.Results: Generally, the size of the vertebrae, vertebral canals and recesses were found to be greater in male patients. The difference was statistically significant for transverse and anteroposterior diameters of the vertebral bodies and sagittal diameter of pedicles on the left side (p\u3c0.05). Comparison of populations revealed statistically significant differences in pedicle dimensions between Pakistani population and others.Conclusions: This study provides anatomical knowledge of the lumbar region in a sample population of Pakistan. There were significant differences in various dimensions of lumbar vertebrae between female and male patients. This would prove to be critical for performing a safe operation

A Short Review on the Development of Salt Tolerant Cultivars in Rice

Rice is staple food for half of the world. With a population of almost 9.6 billion by the year 2050, there is a dire need of developing techniques to improve the crop plants, not only in terms of better yield but also to withstand harsh environmental conditions and stresses like drought, temperature, flood and salinity. Salinity is second to drought stress and hence it is very important to develop crops tolerant to salinity stress. This review discusses the mechanisms of salt tolerance and the recent developments in understanding the complex tolerance phenomena. One way to address the salinity issue is to develop tolerant rice varieties using conventional and modern breeding techniques for which screening the rice germplasm for the varieties with desired traits is critical. Conventional methods to develop tolerant rice varieties are discussed along with modern biotechnology techniques are also discussed. Quantitative Trait Loci (QTL) and Marker Assisted Selection (MAS) are promising techniques. In addition to these modern techniques, some recent developments in the fields of transgenic plants, haploid breeding and Somaclonal variations have also been discussed. The limited knowledge about molecular and genetic mechanisms to tolerate abiotic stresses, however is a barrier to efficiently develop tolerant cultivars. A combination of conventional and modern biotechnology techniques could possibly open up the new ways

Paper Session II-C - Satellite Remote Sensing for Environment and Resource Managment

In the recent years there have been valuable achievements in data pre-processing r image processing and interpretation and other related techniques. These developments in the field of satellite remote sensing have resulted in much more useful studies of environment and resource management. We present a review of some of such studies with emphasis on different land use /landcover features in some urban areas of Pakistan. These studies were made using SPOT multispectral and panchromatic data. Our analysis will be found useful for updating information of different urban features. In the end we present our future programs regarding the resource management and environment using earth resource satellites like LANDSAT and SPOT

Characterization of Malaysian Wild Bananas Based on Anthocyanins

The male buds of 16 Musa species (Musaceae) populations were investigated by HPLC for the occurrence of anthocyanins. The investigation was based on the presence of 6 anthocyanins. The 16 Musa samples could be classified into three distinct species i.e. Musa acuminata, Musa violascens and Musa balbisiana. Musa acuminata could be divided into two subspecies : malaccensis (lowland) and tmncata (highland) according to their constituents and content of major anthocyanins. No variation was observed in the composition of the anthocyanins of Kedah type ssp. siamea and Selangor types ssp. malaccensis. The classification of M. acuminata into two subspecies based on anthocyanin data further supported the current taxonomic grouping of the species

Morphological Characterization of Malaysian Wild Banana Musa Acuminata

Fourteen populations of Musa acuminata ranging from populations in the lowlands of northern (ssp. siamea) to central Malaysian region (ssp. malaccensis) and highland banana (ssp. truncata) were characterized based on chromosome number and 46 morphological characters. A large amount of variation was observed within the populations. However, only highland bananas appeared morphologically distinct. Lowland populations both from northern and central Malaysia were found to be overlapping and no distinguishing pattern was observed. The morphological characters found variable within these populations were related to developmental changes and mutations. The results obtained in this study were not revolutionary. However, the survey of a large number of characters treated with multivariate techniques further sharpened the existing groupings of the Musa acuminata subspecies

Effect of the learning support and the use of project management tools on project success: The case of Pakistan

This study examines the effect of learning support on project success with mediation effect of the use of project management tools. Data were collected form 40 international donor funded projects at federal level in Pakistan. The results suggest that learning support has a positive and significant effect on the use of project management tools which in turn has a similar effect on project success. Results also show that use of project management tools has a significant mediation effect between learning support and the project success. Keywords: Project management, Project management tools, Learning support, International development agencie

Detection of Four Novel Polymorphisms in PrP gene of Pakistani sheep (Damani and Hashtnagri) and goats (Kamori and Local Hairy) breeds

Scrapie is a fatal neurodegenerative disorder of sheep and goats caused by post-translational conformational change in the host-encoded prion protein (PrPC). Susceptibility or resistance to scrapie has been associated with the presence of polymorphisms in the prion protein (PrP) gene. In the present study, we analyzed the PrP gene sequence to determine the frequency of polymorphisms in 56 sheep (28 each from Damani and Hashtnagri breeds) and 56 goats (28 each from Kamori and Local Hairy breeds). A total of 7 amino acid polymorphisms were detected in the PrP gene for sheep and 4 for goats. These amino acid polymorphisms were combined in 13 alleles and 15 genotypes in sheep and 5 alleles and 6 genotypes in goats. The overall frequency of the most sheep scrapie-resistant polymorphism (Q171R) was calculated to be 0.107. The most scrapie-susceptible polymorphism (A136V) was not detected in any of the studied sheep. The overall frequency of scrapie-associated polymorphism (H143R) in goats was found to be 0.152. Along with already known amino acid polymorphisms, two novel polymorphisms were also detected for each of sheep (Q171N and T191I) and goats (G22C and P63L). However, the overall frequency of these polymorphisms was extremely low

ROLE OF VETERINARIANS IN PROVIDING RESIDUE-FREE ANIMAL FOOD

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