With the fast development of today’s multimedia services, engineers face a huge hurdle that is, the overwhelming need of highly reliable communication over long distances. Cooperative communication is a novel concept which tackles this problem effectively. The direct link is assisted by nodes called relays, which also reduce shadowing and pathloss effects in wireless networks. An added advantage of such a cooperative communication network is that when combined with multiple-input multiple-output (MIMO) antenna systems and cognitive radio networks (CRN), the system performance in terms of spectral efficiency and reliability, can be extremely enhanced without any extra power and spectrum.The concept of cooperative communications in MIMO and CRN systems has gained immense interest in the literature. Most of the research works have assumed Rayleigh fading conditions. In this thesis, the performance of cooperative communications with practical constraints of shadowing is studied. Analytical expressions for the outage probability of cooperative networks under different relaying protocols with selection combining are presented under the assumption of κ − µ shadowing fading. Specifically, the relaying protocols that are investigated are incremental relaying, opportunistic relaying, adaptive amplify-and-forward and decode-and-forward. Furthermore, this system model is simulated and the simulation results are compared with the analytical results. Mathematica, a technical computing tool, is used for numerical estimations using stochastic processes and probability theory. Simulation is done in MATLAB.In this thesis, along with the analytical framework for evaluating outage probability for the system is presented. Simulations are performed for various fading parameters and the results closely match with analytical results which validate the derivations.

Submitted by Deyse Queiroz (deysequeirozz@hotmail.com) on 2018-05-22T18:03:39Z No. of bitstreams: 1 FRANCISCO DE ASSIS DA SILVA - DISSERTAÇÃO - PPGHT - 2017.pdf: 821237 bytes, checksum: 42afa05681517bd46df4caf1b3274a96 (MD5) / Made available in DSpace on 2018-05-22T18:03:39Z (GMT). No. of bitstreams: 1 FRANCISCO DE ASSIS DA SILVA - DISSERTAÇÃO - PPGHT - 2017.pdf: 821237 bytes, checksum: 42afa05681517bd46df4caf1b3274a96 (MD5) Previous issue date: 2017-10-19 / Um dos maiores gargalos encontrado pelos produtores de hortaliças folhosas na região semiárida, são os fatores climáticos, como temperatura e luminosidade excessiva, fazendo com que a cultura da alface não se desenvolva de forma eficaz, com isso, faz-se necessário criar alternativas capazes de atenuar esse estrese causado as plantas. Deste modo, foi conduzido um experimento em uma área experimental da Universidade Federal de Campina Grande, no Centro de Ciências e Tecnologia Agroalimentar UFCG/CCTA, de abril a junho de 2017, com objetivo de avaliar o crescimento e a produção de plantas da alface sombreada com diferentes cores de agrotêxtil e cobertura do solo com mulching nas condições edafoclimáticas do município de Pombal-PB. O delineamento experimental utilizado foi em blocos casualizados com parcelas subdivididas do tipo 5x2. A parcela foi composta pelas cores de agrotêxtil com gramatura de 15 g.m2 (lilás, branca, verde e amarela e cultivo a céu aberto) e a subparcela composta pela cobertura do solo (com e sem mulching). Por ocasião da colheita avaliou-se, altura de plantas e diâmetro de plantas, comprimento do caule e da raiz, diâmetro do caule, número de folhas por planta, massa seca de raiz, caule, folha, parte aérea e total, massa fresca da parte aérea e produtividade. O agrotêxtil de cor lilás e amarela apresentaram incrementos na fitomassa e produção da alface. Para as características de partição de massa na planta, as telas de cor lilás e amarela se destacaram em relação às demais apresentando assim as melhores médias. Para cobertura do solo com mulching, observou-se que as plantas que foram cultivadas em canteiros sem a presença do mulching apresentaram melhores médias para as variáveis estudadas. Deste modo, foi observado que a plantas desenvolveram-se melhor com o auxílio do sombreamento quando comparado com o tratamento controle (testemunha) o cultivo a céu aberto. A utilização do mulching como cobertura do solo nas condições do estudo diminuiu o crescimento e consequentemente a produção da alface. / One of the biggest bottlenecks found by leafy vegetable growers in the semi-arid region is the climatic factors, such as temperature and excessive luminosity, so that lettuce culture does not develop efficiently, so it is necessary to create alternatives capable of plants. Thus, an experiment was conducted in an experimental area of the Federal University of Campina Grande, UFCG / CCTA in Center of Science and Agro-food Technology , from April to June 2017, with the objective of evaluating the growth and production of shaded lettuce with different colors of agrotêxtil and mulching in the soil and climatic conditions of the city of Pombal-PB. The experimental design was a randomized block with subdivided plots of type 5x2. The plot consisted of the agrotêxtil colors with a grammage of 15 g.m2 (lilac, white, green and yellow and open cultivation) and the subplot composed by the soil cover (with and without mulching). Plant height and diameter, root and stem length, stem diameter, number of leaves per plant, root dry mass, stem, leaf, shoot and total mass, fresh mass of shoot and productivity. The agrotêxtil of lilac and yellow color presented increases in the phytomass and lettuce production. For the mass partition characteristics in the plant, the lilac and yellow color screens stood out in relation to the others, thus presenting the best averages. For soil cover with mulching, it was observed that the plants that were cultivated in beds without the presence of mulching presented better means for the studied variables. Thus, it was observed that the plants were better developed with the aid of shading when compared to the control treatment (control) the cultivation in the open. The use of mulching as a soil cover under the study conditions decreased the growth and consequently the lettuce production.

The Deepwater Horizon oil spill that started on April 20, 2010, in the Gulf of Mexico was the largest marine oil spill in the history of the petroleum industry. There was an unexpected and prolonged sedimentation event of oil-associated marine snow to the seafloor due to the oil spill. The sedimentation event occurred because of the coagulation process among oil associated marine particles. Marine scientists are developing models for the coagulation process of marine particles and oil, in order to estimate the amount of oil that may reach the seafloor along with marine particles. These models, used certain assumptions regarding the shape and the texture parameters of marine particles. Such assumptions may not be based on accurate information or may vary during and after the oil spill. The work performed here provided a quantitative analysis of the assumptions used in modeling the coagulation process of marine particles. It also investigated the changes in model parameters (shape and texture) during and after the Deepwater Horizon oil spill in different seasons (spring and summer). An Interactive Visualization Application was developed for data exploration and visual analysis of the trends in these parameters. An Interactive Statistical Analysis Application was developed to create a statistical summary of these parameter values.

A novel fuzzy system named as 2-way fuzzy system is developed by combining the intuitionistic fuzzy set theory with the fuzzy systems theory. The developed system is used in modelling and minimizing uncertainty and inconsistency. Uncertainty is the width of the interval introduced by the independent assignment of membership and nonmembership functions of the intuitionistic fuzzy sets / and inconsistency is the violation of the consistency inequality in this assignment. The uncertainty and inconsistency is reduced through a 2 phase training. An evaluation of the degree of reduction of inconsistency is carried out at the end of the rst phase of training by forming the shadowed set patterns of the membership and nonmembership functions. The system is further trained for a second phase in order to reduce uncertainty. There are three dierent methods developed for the stability analysis of fuzzy systems. The rst method is based on the approximating sequences technique, and the design turns into an optimal control problem. In the sec ond analysis, describing function of a 2-way fuzzy system is evaluated analytically, and a systematic design approach is developed using describing function technique. The last analysis technique employs the Lie algebra theory in the stability analysis of Takagi-Sugeno fuzzy systems. The theoretical results are simulated on an application system, which is a exible-joint robot arm system.