Innovative Theoretical Approaches Used for RF Power Amplifiers in Modern HDTV Systems

The essential purpose of this chapter is to introduce theoretical and numerical approaches that can be used for modeling nonlinear effects that appear intrinsically in the design of power amplifiers that have been used widely in many modern high-density television (HDTV) architectures. Important effects like the pre-distortion using adaptive techniques, with distinct characteristics like amplitude, phase, and frequency, as well as, their specific nature such as AM/AM, AM/PM, PM/AM, and PM/PM, and constitute one of the main directions of this research. All theoretical and technological approaches have been supported by a consistent set of numerical data performed with one of the most important platform of simulations used in the great area of Radio Frequency (RF) and Microwave structures. As a direct application, we are introducing some efficient processes that can be used for the characterization of RF systems with a set of consistent laboratorial measures that permit us to visualize the effective cost and a complete architecture for the characterization of high-power amplifiers. With the continuous and innovative technological demand that is imposed by the international marketing has a great importance to find versatile systems that are capable of measuring several amplifier characteristics, as gain, output power, inter-modulation distortion of different signals, efficiency, current, and temperature that constitute another direction of research that has been demanded strongly for news advanced technologies used widely in modern HDTV systems

Physiological responses of Amazonian flooded plants to the global climate change

Conforme previsões do último relatório do IPCC (Intergovernmental Panel of Climatic Change) em 2007, até meados deste século haverá um aumento na concentração de CO2 na atmosfera podendo chegar a 720 μmol mol-1. Consequentemente haverá uma elevação da temperatura de até +3 °C, o que ocorrerá em conjunto com mudanças no padrão de precipitação. O mesmo relatório sugere que isto poderá acarretar uma substituição gradual da floresta tropical por vegetação similar a uma savana na parte oriental da Amazônia, porém nada é conclusivo. Diante dessas possibilidades, pergunta-se - Como as espécies de árvores que compõem as regiões de alagamento da Amazônia irão responder às alterações climáticas por vir? Apesar dessas previsões serem pessimistas, o alagamento ainda ocorrerá por vários anos na Amazônia e é de grande importância compreender os efeitos do alagamento sobre as respostas fisiológicas das plantas num contexto das mudanças climáticas. Os principais efeitos sobre a sinalização metabólica e hormonal durante o alagamento são revisados e os possíveis efeitos que as mudanças climáticas poderão ter sobre as plantas amazônicas são discutidos. As informações existentes sugerem que sob alagamento, as plantas tendem a mobilizar reservas para suprir a demanda de carbono necessário para a manutenção do metabolismo sob o estresse da falta de oxigênio. Até certo limite, com o aumento da concentração de CO2, as plantas tendem a fazer mais fotossíntese e a produzir mais biomassa, que poderão aumentar ainda mais com um acréscimo de temperatura de até 3 °C. Alternativamente, com o alagamento, há uma diminuição geral do potencial de crescimento e é possível que quando em condições de CO2 e temperatura elevados os efeitos positivo e negativo se somem. Com isso, as respostas fisiológicas poderão ser amenizadas ou, ainda, promover maior crescimento para a maioria das espécies de regiões alagáveis até o meio do século. Porém, quando a temperatura e o CO2 atingirem valores acima dos ótimos para a maioria das plantas, estas possivelmente diminuirão a atividade fisiológica.According to the last report of IPCC (Intergovernmental Panel of Climatic Change, 2007) an increase in atmospheric CO2 concentration to ca. 0.072% is predicted to occur until the middle of this century. As a result, a tandem elevation of temperature of ca. +3 °C and a decrease in precipitation are to be expected. It has also been suggested that this scenario may lead to a gradual substitution of the tropical forest for savanna-like vegetation in Eastern parts of the Amazon. Within this perspective, a worth question is how the tree species that make up the Amazonian floodplains will respond to the global climatic change? Although predictions have been quite pessimistic, flooding of part of the Amazon will continue to occur for several years and it is important to understand its synergistic effects within the scenario of climate change. In this work, features related to plant metabolism and hormonal signaling during flooding is revised, and the possible effects that the climatic changes might have on plants from the Amazon are discussed. The information available in the literature suggests that under flooding, plants tend to mobilize storage compounds to supply carbon demand needed for maintenance metabolism under the effect of stress caused by the lack of oxygen. In contrast, under elevated CO2 concentration, plants tend to increase photosynthesis and biomass. With an increase of about 3 °C these parameters may increase even more. Alternatively, with flooding, there is a general decrease in growth potential and it is possible that while favorable conditions of elevated CO2 and temperature prevail, the positive effects may be counterbalanced by the negative effects of flooding. Thus, the physiological responses might be imperceptible or promote further growth up to the middle of the 21st Century for most species that occur in the floodplains. However, if temperature and CO2 levels surpass the threshold of optimal conditions for most plants, a decrease in physiological activity is to be expected

Early Identification of Abused Domains in TLD through Passive DNS Applying Machine Learning Techniques

DNS is vital for the proper functioning of the Internet. However, users use this structure for domain registration and abuse. These domains are used as tools for these users to carry out the most varied attacks. Thus, early detection of abused domains prevents more people from falling into scams. In this work, an approach for identifying abused domains was developed using passive DNS collected from an authoritative DNS server TLD along with the data enriched through geolocation, thus enabling a global view of the domains. Therefore, the system monitors the domain’s first seven days of life after its first DNS query, in which two behavior checks are performed, the first with three days and the second with seven days. The generated models apply the machine learning algorithm LightGBM, and because of the unbalanced data, the combination of Cluster Centroids and K-Means SMOTE techniques were used. As a result, it obtained an average AUC of 0.9673 for the three-day model and an average AUC of 0.9674 for the seven-day model. Finally, the validation of three and seven days in a test environment reached a TPR of 0.8656 and 0.8682, respectively. It was noted that the system has a satisfactory performance for the early identification of abused domains and the importance of a TLD to identify these domains

Management control practices in startups with financial and non-financial success

As práticas de controle de gestão são rotinas e procedimentos formais e informais, capazes de implementar estratégias e manter ou alterar padrões organizacionais fundamentais para explorar ao máximo o potencial das Startups. Este estudo teve como objetivo identificar as práticas de controle de gestão em Startups com sucesso financeiro e não financeiro. Trata-se de uma pesquisa descritiva, com abordagem qualiquantitativa e estudo de casos múltiplos. Foram analisadas quatro Startups membros da Associação Gaúcha de Startups (AGS) e a coleta dos dados ocorreu por meio de survey na plataforma Google Forms e de entrevistas semiestruturadas online. Verificou-se que as Startups desse grupo fazem maior uso de práticas inovativas em relação às tradicionais. Constatou-se que a prática tradicional da elaboração e controle do fluxo de caixa e a prática inovativa do benchmarking são as principais práticas de controle de gestão adotadas pelas Startups desta pesquisa. São necessárias métricas financeiras e não financeiras para a avaliação de sucesso de Startups, entre elas, ferramentas de controle, transparência, potencial de escalabilidade, conhecimento da marca e presença junto a clientes e fornecedores. Este estudo pode auxiliar empresários na construção de seus negócios, na difusão de ideias inovativas de controle de gestão e na promoção de transparência aos investidores com interesse em Startups. Concluiu-se que a adoção de práticas de controle de gestão em Startups com sucesso financeiro e não financeiro é essencial à estruturação da empresa rumo à escalabilidade.Management control practices are formal and informal routines and procedures capable of implementing strategies and maintaining or changing fundamental organizational patterns for exploiting Startups maximum potential. This study aimed to identify management control practices in Startups with financial and non-financial success. This research is classified as descriptive, with a qualiquantitative approach and study of multiple cases. Four Startups members of the Associação Gaúcha de Startups were analyzed, and the data collection was carried out through a survey on Google Forms platform and through an online semi-structured interview. It was verified that the Startups of this group make greater use of innovative practices compared to traditional ones. It was found that the traditional practice of preparing and controlling cash flow and the innovative practice of Benchmarking are the main management control practices adopted by the Startups of this research. Financial and non-financial metrics are necessary for the success assessment of Startups, including control tools, transparency, scalability potential, brand awareness and presence with customers and suppliers. This study helps entrepreneurs in building their businesses, in spreading innovative ideas of management control and in promoting transparency to those interested in Startups. It was concluded that the adoption of management control practices in Startups with financial and non-financial success is essential to the structuring of the company towards scalability

A Insustentável leveza da complexidade

This assay deals the process of collective denial, a mental block related with the confrontation of a person with subjects of high complexity, and the possibility that this process might be related with the delay of society to recognize the existence of the global climatic changes for more than 30 years. However, the collective denial now seems to be decreasing in a society with higher access to information. This new well informed society demands transparency and participation in the process of production and use of knowledge. During this century we will have to deal with a new form of making science which will possibly have a much more significant participation of society.Este ensaio trata do processo de negação coletiva, um bloqueio mental causado pelo confronto com temas de alta complexidade e a possibilidade de que este processo tenha retardado reconhecimento da importância das mudanças climáticas globais e seus efeitos por mais de 30 anos. Mas a manifestação da negação coletiva vem diminuindo com a sociedade cada vez mais informada devido aos meios de comunicação. O pronto acesso à informação tende a gerar uma sociedade mais crítica e menos propensa a acreditar dogmaticamente nos conceitos científicos. Esta nova sociedade já demanda transparência e quer participar do processo de obtenção e uso do conhecimento. Neste século teremos que lidar uma nova forma de fazer ciência, que provavelmente terá participação bem mais significativa da sociedade

Viabilidade do cultivo de cana-de-açúcar e sistemas agroflorestais

O Brasil é o principal produtor mundial de cana-de-açúcar e seu sistema de produção tem sofrido mudanças devido a aspectos legais e técnicos. Na região de Piracicaba, grande parte dos pequenos produtores cultiva cana-de-açúcar em áreas de grande declividade, mas a mecanização da colheita tem inviabilizado seu cultivo nesta condição. Assim, foram identificados e selecionados terras e árvores visando compatibilizar a produção da cultura e a conservação de recursos naturais em sistemas agroflorestais. Os solos presentes no intervalo de 12-20% de declividade foram identificados, selecionamos árvores com potencial para serem cultivadas com cana-de-açúcar foram selecionados e os desenhos dos sistemas a serem adotados foram avaliados. A classe de declive identificada ocupa área de 11.556 ha e Argissolo Vermelho-Amarelo e Neossolo Litólico são os solos mais representativos. As espécies arbóreas exóticas coco-anão-verde, eucalipto, pupunheira, seringueira e outras oito espécies nativas têm potencial para serem cultivadas com cana-de-açúcar em sistemas agroflorestais de aléias em contorno. Sugere-se o plantio inicial de árvores exóticas domesticadas e a introdução gradual de espécies nativas não domesticadas, de acordo com suas exigências ecológicas.Brazil is the world's main sugarcane producer and the production system has changed abiding to legal and technical recommendation. In Piracicaba many smallholders grow sugarcane in steep areas. Under such situation, mechanization at harvest makes cultivation impossible. This work assess the viability of agroforestry systems on joining crop production and conservation of natural resources. Soils at 12-20% slope class were identified, tree species which could be cultivated along with sugarcane were selected, and the design of the systems to be adopted was evaluated. Identified area occupies 11,556 ha and the most representative soil types are Typic Kandiuldult and Lithic Hapludoll. The exotic species coconut, eucalyptus, pejibaye and rubber, and eight native species have potential to be grown in contourhedgerows with sugarcane. Initial planting of exotic, domesticated trees is recommended, and gradual introduction of native, non-domesticated species, can be set according to their ecological requirements