Considering that irrigation occupies the major percentage of consumed water in agriculture and that Brazil intends to expand considerably its irrigated area in the coming decades, there is a growing need in improving the irrigation water management, mostly in regions with limited availability of water or occurrences of hydric deficiency periods. Therefore, the increase of technologies for performing irrigation using environmental information is becoming important because they enable the maximization of water and energy consumption, maintaining or even improving the yield and quality of agricultural production. This work proposes a context-aware remote sensing architecture for irrigation and its contributions are: (a) the development of two prototypes of a moisture and precipitation meter based on the proposed architecture using open hardware technologies; (b) the development of a context taxonomy that defines the types of information that can be used in the prototype s architecture; and (c) a comparison between two different types of soil moisture sensors. For the validation of the architecture, two case studies were realized to verify the correct functioning of the architecture components, as well as a data collection was performed to make the comparison between a resistive low-cost sensor produced at the Federal University of Santa Maria, and a high-accuracy and high-cost frequency domain reflectometry (FDR) sensor (CS616 - Campbell Scientific, United States). The results obtained from the analyzed data were satisfactory, where it was verified that the architecture is viable, meeting the requirements to which it has proposed. In addition, the comparison performed showed a determination coefficient of up to 95 % between the low-cost resistive soil moisture sensors and the soil moisture sensors CS616 of Campbell R . / Considerando que a irrigação ocupa a maior porcentagem da água consumida na agricultura, e que o Brasil pretende expandir consideravelmente a sua área irrigada nas próximas décadas, há uma crescente necessidade de melhorar o manejo da água de irrigação, principalmente em regiões com reduzida disponibilidade de água ou ocorrência de períodos de deficiência hídrica. Por isso, o incremento de tecnologias na realização da irrigação utilizando-se de informações referentes ao ambiente, estão tornando-se importantes por permitirem a maximização do uso da água e energia, mantendo, ou mesmo melhorando, o rendimento e a qualidade da produção agrícola. Este trabalho propõe uma arquitetura de sensoriamento remoto sensível ao contexto para irrigação, e suas contribuições são: (a) o desenvolvimento de dois protótipos de um medidor de umidade e pluviometria baseados na arquitetura proposta utilizando tecnologias open hardware; (b) o desenvolvimento de uma taxonomia de contextos que define os tipos de informações que podem ser utilizadas na arquitetura dos protótipos; e (c) uma comparação entre dois tipos distintos de sensores de umidade do solo. Para a validação da arquitetura, foram realizados dois estudos de caso para verificar o correto funcionamento dos componentes da arquitetura, bem como a coleta de dados para efetuar a comparação entre um sensor resistivo de baixo custo produzido na Universidade Federal de Santa Maria, e um sensor de alta precisão e custo que utiliza a técnica de reflectometria no domínio da frequência (FDR) (CS616 - Campbell Scientific, Estados Unidos). Os resultados obtidos com os dados analisados foram satisfatórios, onde verificou-se que a arquitetura atende aos requisitos aos quais se propôs. Além disso, a comparação realizada apresentou coeficientes de determinação de até 95% entre os sensores resistivos de umidade do solo de baixo custo e os sensores de umidade do solo CS616 da Campbell R .

In computer security, cryptographic algorithms and protocols are required to ensure security of data and applications. This research investigates techniques to reduce the energy consumed by cryptographic hash functions. The specific hash functions considered are Message Digest-2 (MD2), Message Digest-5 (MD5), Secure Hash Algorithm-1 (SHA-1) and Secure Hash Algorithm-2 (SHA-2). The discussion around energy conservation in handheld devices like laptops and mobile devices is gaining momentum. Research has been done at the hardware and operating system levels to reduce the energy consumed by these devices. However, research on conserving energy at the application level is a new approach. This research is motivated by the energy consumed by anti-virus applications which use computationally intensive hash functions to ensure security. To reduce energy consumption by existing hash algorithms, the generic energy complexity model, designed by Roy et al. [Roy13], has been applied and tested. This model works by logically mapping the input across the eight available memory banks in the DDR3 architecture and accessing the data in parallel. In order to reduce the energy consumed, the data access pattern of the hash functions has been studied and the energy complexity model has been applied to hash functions to redesign the existing algorithms. These experiments have shown a reduction in the total energy consumed by hash functions with different degrees of parallelism of the input message, as the energy model predicted, thereby supporting the applicability of the energy model on the different hash functions chosen for the study. The study also compared the energy consumption by the hash functions to identify the hash function suitable for use based on required security level. Finally, statistical analysis was performed to verify the difference in energy consumption between MD5 and SHA2.

The Internet is rapidly growing in complexity, with increasing negative environmental and social impact. While heating and lighting are tangible examples of energy consumption, internet usage is not perceived as such. Therefore, it opens up opportunities for new, energy-efficient, slower, resource-saving and mindful protocols for the Internet to emerge. I propose Glow OS, an operating system that enables individuals and communities to align their online activities with intermittent solar energy. This system aims to accelerate the transition to a fossil-free internet by promoting solar literacy in the spirit of joy.

Mobile learning (m-learning) is still in its infancy, and great efforts should be made so as to investigate the potentials of an educational paradigm shift from the traditional one-size-fits-all teaching approaches to an adaptive learning that can be delivered via mobile devices. Thus, the next challenge has been identified from this implication: How learning design can be implemented so as to benefit from the m-learning characteristics and achieve adaptation and personalization of the individual learning process in different contexts? An important factor for achieving personalized and adaptive m-learning has been the pedagogically meaningful and technically feasible processing of learners’ contextual information. Therefore in this work, design and delivery of personalized educational scenarios are suggested to be re-thought so as to benefit from the affordances of mobile technologies and the learners’ context / El aprendizaje móvil (m-learning) se encuentra todavía en su infancia y grandes esfuerzos se deben hacer para investigar el cambio de paradigma educativo, desde la forma de enseñanza tradicional de 'un modelo único para todos' a un aprendizaje adaptativo que se pueda entregar a través de dispositivos móviles. De esta manera, el siguiente desafío ha sido identificado por esta implicación: ¿Cómo se puede implementar el diseño instruccional con el fin de beneficiarse de las características del m-learning y lograr la adaptación y personalización del proceso de aprendizaje personal en diferentes contextos? Un importante factor para lograr un m-learning personalizado y adaptable ha sido el procesamiento de la información contextual de los estudiantes. Por lo tanto, en este trabajo se sugiere que sean re-pensados el diseño y la entrega de escenarios educativos orientados a la personalización del aprendizaje y que se beneficien de las potencialidades de las tecnologías móviles y el contexto de los estudiantes