Modulação quantizada para sistemas com codificação wavelet sujeitos ao desvanecimento rayleigh

Wavelet coding is an efficient technique to overcome the multipath fading effects, which are characterized by fluctuations in the intensity of the transmitted signals over wireless channels. Since the wavelet symbols are non-equiprobable, modulation schemes play a significant role in the overall performance of wavelet systems. Thus the development of an efficient design method is crucial to obtain modulation schemes suitable for wavelet systems, principally when these systems employ wavelet encoding matrixes of great dimensions. In this work, it is proposed a design methodology to obtain sub-optimum modulation schemes for wavelet systems over Rayleigh fading channels. In this context, novels signal constellations and quantization schemes are obtained via genetic algorithm and mathematical tools. Numerical results obtained from simulations show that the wavelet-coded systems derived here have very good performance characteristics over fading channels

Sobre formas e processos: projeto de um condomínio de casas a partir de princípios da gramática da forma

With the intention of studying and developing the design process based on a specific methodology, the object of this work is to present the design of a gated condominium community in Natal based on the application of principles of shape grammar, used in their design process. The shape grammar is a design method developed in the 1970s by George Stiny and James Gips. It is used for the analysis of the project as well as for its synthesis, with the goal of creating a "formal vocabulary" through mathematical and/or geometrical operations. Here, the methodology was used in the synthesis of the design process, through the relationship between formal subtractions and the houses’ architectural planning. As a result, five dwellings configurations were proposed, each one different from the other with respect to their shape and architectural programming, distributed in three twin groups, which are repeated until the final total of nine architectural volumes. In addition to studies of the condominium’s ventilation and the buildings’ shading simulations, studies of spatial flexibility and acoustic performance were also performed. The mapping of the design process, one of the specific objectives of the dissertation, was composed not only by the record of formal constraints (the preparation and application of rules), but also by physical, environmental, legal and sustainability aspects in relation to, on one hand, the optimization of the shading and passive ventilation for hot and humid climates, and, on the other hand, the modulation and rationalization of the construction.

Simulação computacional como ferramenta de auxílio ao projeto: aplicação em edifícios naturalmente ventilados no clima de Natal/RN

Natural air ventilation is the most import passive strategy to provide thermal comfort in hot and humid climates and a significant low energy strategy. However, the natural ventilated building requires more attention with the architectural design than a conventional building with air conditioning systems, and the results are less reliable. Therefore, this thesis focuses on softwares and methods to predict the natural ventilation performance from the point of view of the architect, with limited resource and knowledge of fluid mechanics. A typical prefabricated building was modelled due to its simplified geometry, low cost and occurrence at the local campus. Firstly, the study emphasized the use of computational fluid dynamics (CFD) software, to simulate the air flow outside and inside the building. A series of approaches were developed to make the simulations possible, compromising the results fidelity. Secondly, the results of CFD simulations were used as the input of an energy tool, to simulate the thermal performance under different rates of air renew. Thirdly, the results of temperature were assessed in terms of thermal comfort. Complementary simulations were carried out to detail the analyses. The results show the potentialities of these tools. However the discussions concerning the simplifications of the approaches, the limitations of the tools and the level of knowledge of the average architect are the major contribution of this study

Modelos para análise e dimensionamento de painéis de alvenaria estrutural

The main objective of this thesis was the study of bracing panels of structural masonry, by applying the Finite Element Method and Strut and Tie Method. It was analyzed the following aspects: the effect of orthotropy on the behavior of the panels; distribution of horizontal forces between panels for buildings; comparison between Equivalent Frame and Finite Elements models; panels design with the Strut and Tie Method. The results showed that one should not disregard the orthotropy, otherwise this can lead to models stiffer than the real. Regarding the distribution of horizontal forces, showed that the disregard of lintels and shear deformation leads to significant differences in the simplified model. The results showed also that the models in Finite Element and Equivalent Frame exhibit similar behavior in respect to stiffness of panels and stress distribution over the sessions requested. It was discussing criteria for designing Strut and Tie Method models in one floor panels. Then, the theoretical strength these panels was compared with the rupture strength of panels tested in the literature. The theoretical maximum strength were always less than the rupture strength of the panels obtained in tests, due to the fact that the proposed model cannot represent the behavior of the masonry after the start of the panel cracking due to plasticization of the reinforcement

Produção artesanal : análise do método de intervenção de design no artesanato potiguar sob o ponto de vista dos atores envolvidos no processo

This work presents an analysis of the method of intervention used in the craft of design by SEBRAE in Rio Grande do Norte under the viewpoint of the actors involved, especially the craftsmen and design consultants. The research methodology used was based on the ergonomic work analysis - AET, applying observational techniques and interactive. Data tabulated from the matrix to include comments were analyzed in order to allow the generation of qualitative and quantitative information. The results of this research allow us to affirm that for the process of innovation through the design of intervention are satisfactory for all involved, it is necessary that the bonds of interaction are established and the joint actions in the innovation process to bear fruit in favor sustainability of artisan groups

Integrating strategic and sustainable design approach for innovation process: a cement case study

Global society and technology have changed the relationships of the market. Quality and cost are not the main aspects of any industrial product. On the other hand, design, innovation and sustainability became significant requirements to company’s competitiveness. In this context, the design approach has shown evolutions, integrating social and environmental aspects beside traditional aspects such as technical and economic. Still, design has been becoming a strategic opportunity for companies, improving their competitiveness and increasing their market share. Thus, this research has analyzed the integration of both the Sustainable Design and Strategic Design Coaching (SDC) method in the making decision activities of companies. A cement company (BQMIL) was assigned as case study, in which the previous results have pointed out the significant hole of those concepts to generate Eco-innovation and Eco-Brand to increase its market share, corroborating the expectative of the design team