Full Diversity Multidimensional Codebook Design for Fading Channels: The Combinatorial Approach

International audiencePrevious transmission techniques for fading channels that exploit signal space diversity (SSD) are based on rotation or precoding of an original signal constellation. In this work, we follow a completely different approach to design full diversity multidimensional codebooks whose implementation has low complexity and requires little storage. The design consists of finding good permutations of the labels of points in a fixed grid. We consider both the uniform and the Gaussian-shaped grids. An ensemble average performance based on an enumerative analysis of the error events is presented, which brings some insight into the problem. Three low-complexity algorithms are then proposed to find good permutations sets. Both analytical and simulation results confirm the good performance of the proposed codebooks, which can be considered as good candidates for practical communications systems

Doses and potassium partitioning methods in soybean production components in an Amazonian savanna

After nitrogen, potassium is the macronutrient most required by soybean. To meet soy bean growth demands, it is necessary to use high K doses, which can lead to losses via leaching. The objective of the current study was to evaluate the effect of doses and methods of K fertilization on the components of soybean production, in the Yellow Latosol of an Amazonian savanna. The experiment was conducted using randomized complete block design with four replicates. Plots consisted of two fertilization methods (M1 – fertilization on planting and at 35 days after emergence - DAE and M2 – on planting, then divided between 20 and 35 DAE). Subplots where five doses of potassium (K2O at 0, 40, 80, 120 and 160 kg ha-1) were randomized. Measured variables were: plant stand (PS), plant height (PH), height of first pod insertion (FP), number of pods per plant (PP), bean mass per plant (BM), and bean yield (BY). Because of the low exchangeable K content and medium texture of the study soil, deployed methodology consisting of plant fertilization and two applications to facilitate high soybean yields. Agronomic efficiency proved to be a good indicator for assaying the best K2O dose, as it is sensitive to initial soil exchangeable K levels. The dose giving maximum agronomic efficiency was 88.5 kg ha-1 of K2O, converting each kg of K2O in 14.3 kg of soybeans

Proposta de implementação do sistema VAC (Velocidade de Atravessamento Constante) para maximizar o processo produtivo: estudo de caso na TS Indústria de Etiquetas

<p>Para que uma organização se mantenha no mercado, esta deve ter como princípio o objetivo de satisfazer as pessoas. Para isso, é indispensável verificar se o produto ou o serviço contém o nível de qualidade exigido por seus clientes. Neste sentido, este artigo apresenta-se como estudo de caso aplicado na TS Indústria de Etiquetas e Comércio de Equipamentos de Informática Ltda., onde propõe-se a implementação do sistema VAC (Velocidade de Atravessamento Constante). Diante disto, o presente artigo, tem como questão norteadora: Como a implementação do sistema VAC (Velocidade de Atravessamento Constante) pode contribuir com a maximização do atendimento no prazo da demanda da carteira de pedidos na indústria de etiquetas? O objetivo geral deste estudo é introduzir um novo sistema na área de produção para contribuir com o aumento da produtividade, entrega no prazo e satisfação do cliente. A pesquisa estrutura-se com bases bibliográficas, métodos exploratórios e qualitativos. Como resultados, apresenta-se uma proposta que, por meio da ferramenta 5W2, aspira a implantação de ações em forma de plano de melhorias, o qual aponta novas metodologias que facilitam a gestão da empresa, de modo que estas táticas sejam elaboradas e empregadas conforme as necessidades encontradas.</p><p>In order for an organization to stay competitive in the market, its fundamental principle should be to satisfy its stakeholders. Therefore, it is essential to verify whether the product or service meets the quality standards demanded by its customers. In this context, this article presents itself as a case study applied to TS Labels Industry and Information Technology Equipment Trading Ltd., proposing the implementation of the Constant Traversal Speed (VAC) system. Thus, this article's guiding question is: How can the implementation of the Constant Traversal Speed (VAC) system contribute to maximizing the timely fulfillment of orders in the label industry? The overall objective of this study is to introduce a new system in the production area to enhance productivity, on-time delivery, and customer satisfaction. The research is structured based on literature reviews, exploratory methods, and qualitative approaches. As results, a proposal is presented that, through the 5W2 tool, envisions the implementation of improvement actions in the form of a plan, indicating new methodologies that facilitate company management. These tactics are designed and implemented according to identified needs.</p&gt