Practical Isolated Searchable Encryption in a Trusted Computing Environment

Cloud computing has become a standard computational paradigm due its numerous advantages, including high availability, elasticity, and ubiquity. Both individual users and companies are adopting more of its services, but not without loss of privacy and control. Outsourcing data and computations to a remote server implies trusting its owners, a problem many end-users are aware. Recent news have proven data stored on Cloud servers is susceptible to leaks from the provider, third-party attackers, or even from government surveillance programs, exposing users’ private data. Different approaches to tackle these problems have surfaced throughout the years. Naïve solutions involve storing data encrypted on the server, decrypting it only on the client-side. Yet, this imposes a high overhead on the client, rendering such schemes impractical. Searchable Symmetric Encryption (SSE) has emerged as a novel research topic in recent years, allowing efficient querying and updating over encrypted datastores in Cloud servers, while retaining privacy guarantees. Still, despite relevant recent advances, existing SSE schemes still make a critical trade-off between efficiency, security, and query expressiveness, thus limiting their adoption as a viable technology, particularly in large-scale scenarios. New technologies providing Isolated Execution Environments (IEEs) may help improve SSE literature. These technologies allow applications to be run remotely with privacy guarantees, in isolation from other, possibly privileged, processes inside the CPU, such as the operating system kernel. Prominent example technologies are Intel SGX and ARM TrustZone, which are being made available in today’s commodity CPUs. In this thesis we study these new trusted hardware technologies in depth, while exploring their application to the problem of searching over encrypted data, primarily focusing in SGX. In more detail, we study the application of IEEs in SSE schemes, improving their efficiency, security, and query expressiveness. We design, implement, and evaluate three new SSE schemes for different query types, namely Boolean queries over text, similarity queries over image datastores, and multimodal queries over text and images. These schemes can support queries combining different media formats simultaneously, envisaging applications such as privacy-enhanced medical diagnosis and management of electronic-healthcare records, or confidential photograph catalogues, running without the danger of privacy breaks in Cloud-based provisioned services

The Demiurge’s Self-Genesis in the Egyptian New Kingdom Religious Hymns (ca. 1539-1077 BC)

UID/HIS/04666/2019The main goal of my PhD is to consider the phraseology present in the New Kingdom religious hymns which explicitly mentions the cosmogonical process, that is, that sheds some light on the way the world came into existence. My research is structured around three core questions: Who creates? (The identity of the Creator); What is created? (The outcomes of the Creation); How is it created? (The processes, mechanisms, and devices used by the Creator to set the World into existence). Nevertheless, there is one particular feature in this corpus that somehow blurs the individuation of these analytical axes: the fact that one of the most mentioned outcomes of the creation in these texts is the Creator himself. The Egyptian term xpr is quintessential in this context since it conveys the idea of “coming to existence” or “assuming/taking a shape” (e.g. BM EA826). Nevertheless, there are other ways of expressing this notion, namely the ones linked to an idea of construction and formation through manual/craft work, employing verbs such as od or nbj (e.g. pLeiden I 344 verso). The deity’s self-creation might as well be rendered by na allusion to a biological process, where the Creator would have engendered (wtT) and given birth (msj) to himself (e.g. BM EA551). In this paper I intend to focus on the different ways through which the Demiurge’s selfgenesis is conveyed in this corpus. On the one hand, I will consider the possible religious meanings and implications of this existential continuity between producer and product. On the other hand, I will link this phenomenon with other cosmogonical aspects attested in these texts, such as the creation of gods (theogony) and human beings (anthropogeny).publishersversionpublishe

Robótica colaborativa para melhorar a ergonomia no posto de trabalho: um estudo de caso na indústria automativa

Doctoral program in Industrial and Systems EngineeringA quarta revolução industrial desenvolveu sistemas inteligentes, nos quais os robôs colaborativos têm um papel principal. Os trabalhadores sofrem fadiga quando expostos aos fatores de risco que causam as lesões musculoesqueléficas relacionados ao trabalho (WMSD). Como os postos de trabalho manuais muitas vezes conduzem a más posturas e movimentos repetitivos, a implementação de sistemas de Colaboração Humano-Robô (HRC) é frequentemente escolhida como uma solução para melhorar a ergonomia no ambiente de trabalho. O Nivel de Colaboração (LoC) significa quais tarefas o robô é capaz de executar como um colega de equipe, o que varia desde o Nivel O ao Nivel 4. Os fatores fisicos, cognitivos e organizacionais interagem diretamente em questões relacionadas com as relações laborais em sistemas complexos. Dependendo do LoC para executar uma tarefa, esperam-se diferentes cargas de trabalho físicas e mentais sobre o ser humano. A Dinâmica de Sistemas (SD) é um método para abordar tais problemas com uma visão sistêmica, modelando, simulando e ajudando a tomada de decisões. Investigações prévias sobre postos de trabalho HRC não qualificam e quantificam os riscos ergonômicos variando com o LoC. Por isso, esta tese propõe um modelo de simulação computacional como parte de uma estrutura para tomada de decisões com objetivos de produtividade e redução do risco de WMSD ao implementar um HRC. Além disso, foi realizado um estudo de caso em um posto de trabalho para comparar resultados com as simulações computacionais. Foi escolhido o tempo de ciclo para medir a produtividade, o método ergonômico Rapid Upper Limb Assessment (RULA) para a avaliação da carga de trabalho fisico, e o questionário NASA Task Load Index (NASA-TU() para a avaliação da carga de trabalho mental. Os resultados mostram que a produtividade aumentou mais de 20% em média, as posturas e a carga de trabalho global melhoraram tanto em simulações computacionais como em simulações reais. Também indica que um LoC mais elevado não garante os melhores resultados em termos de produtividade e ergonomia. A conclusão foi que a estrutura para tomada de decisões baseada em SD, que também inclui avaliações técnicas e económicas, é fundamental para compreender o sistema e obter dados confiáveis. Os trabalhos futuros pretendem desenvolver ainda mais o modelo e aplicar esta estrutura em outras linhas de montagem que considerem a implementação de um sistema HRC.The fourth industrial revolution has seen fast developments in smart systems, in which collaborative robots have a main role. Workers start to fatigue when exposed to Work-related Musculoskeletal Disorders (WMSD) risk factors. As manual handling workstations often lead to awkward postures, repetitive movements and forceful exertions, the implementation of Human-Robot Collaboration (HRC) systems is often chosen as a solution to improve workplace ergonomics. The Level of Collaboration (LoC) means what tasks the robot is capable to perform as a teammate, which varies from Level 0 to Level 4. Physical, cognitive, and organizational factors interact directly on issues related to labor relations in complex systems. Depending on the LoC to perform a task, it is expected different physical and mental workloads over the human being. System Dynamics (SD) is a method to approach such problems with a systemic view by designing, modeling, simulating, and finally making good decisions. Prior research on HRC workstations does not find a solution for qualifying and quantifying ergonomic risks depending on the LoC. Therefore, this thesis proposes a computer simulation model as part of a decision-making framework to achieve productivity goals and to reduce the risk of WMSD when implementing an HRC. Moreover, a case study was conducted in a manual assembly workstation to compare results with the computational simulations. It was chosen cycle time to measure productivity, the ergonomic method Rapid Upper Limb Assessment (RULA) for the physical workload assessment, and the NASA Task Load Index (NASA-TLX) questionnaire for the mental workload assessment. Results show that productivity increased more than 20% on average, postures and the overall workload improved in both computational and real simulations. It also indicates that higher LoC does not guarantee the best results in terms of productivity and ergonomics. The conclusion was that the framework based on system dynamics that also includes technical and economic evaluations is key to understand the system and to make good decisions based on reliable data. Future works intend to further develop the model and to apply this framework in other assembly lines that consider the implementation of an HRC system

Exploring the predictive power of Google searches over the US stock market

A Work Project, presented as part of the requirements for the Award of a Masters Degree in Finance from the NOVA – School of Business and EconomicsThis paper takes search intensity for stock tickers in Google (SVI) as a direct measure of retail investor attention and assesses whether it holds predictive power over short-term market outcomes. In a sample of the most representative US stocks, during the period 2005 – 2008, I provide evidence that (1) surges of investor attention forecast higher stock liquidity and volatility; (2) depending severely on what is considered an abnormal level of SVI, retail investor attention can also be priced; and (3) SVI does not relate to firm-specific features, such as size and value. Furthermore, I extend the investigation to the aggregate market level, finding that investor attention to the market index predicts greater market liquidity, volatility and return

Public prosecutors, political parties, and NGOs are paving the way for vital climate change litigation in Brazil

Though the Bolsonaro government’s approach to land-use and the environment has intensified damage to Brazil’s crucial biological communities, a growing fightback is also laying the foundations for climate change litigation that could be vital for Brazil and the wider world, write Joana Setzer (Grantham Research Institute on Climate Change and the Environment, LSE), Caio Borges (Institute for Climate and Society), and Guilherme Leal (Graça Couto Advogados)

The Effect of rest interval between sets on the number of repetitions performed in the bench press exercise

The aim of the present study was to analyze the effects of different rest intervals on the number of repetitions performed in the bench press exercise. Methods: 6 resistance-trained men (age 24.27±1.61 years, body fat 14.72±5.32 %, body mass 76.60±11.00 kg, 1-RM bench press 98.42±19.78kg) volunteered for the study. Subjects performed a bench press 1-RM test and in two subsequent sessions they performed five maximal sets of the bench press exercise with 70%, 75%, 75%, 80% and 85% of 1-RM and a 1- or 2-minute rest interval between sets. Sessions occurred at least 48h apart, with the last two in a random fashion. Statistical analyzes was made by the student t-test to compare the differences between rest intervals. The number of repetitions performed with the 2-minute rest interval (33.16 ± 6.14) was significantly higher than with 1-minute rest interval (26.67 ± 3.44), (p=0.009) and in sets 2 (p=0.016), 3 (p=0.004) and 4 (p=0.018). The 2-minute rest interval yielded a larger number of repetitions performed throughout the five sets of bench press. Furthermore, the subjects were unable to maintain a large number of repetitions even when a 2-minute rest interval was taken. This indicates that larger rest intervals may be necessary when training with this intensity, especially if the maintenance of exercise volume is desired

A cruz da questão: o uso de argumentos laicos na permanência de símbolos católicos em locais públicos brasileiros

This investigation aims to examine discourses produced by the Catholic episcopate in opposition to the possibility of religious symbols being removed from public establishments. For that, we observed the responses from the episcopacy to the 3rd National Human Rights Program (PNDH-3), released by the Brazilian federal government in late 2009. The document features a proposal to restrain the display of confessional signs in federal buildings. When analyzing the ecclesiastical arguments, it is clear the "weapon of culture" is used in the controversy. That is an approach which distances itself from the discourse models historically adopted by the Church in Brazil. The secular State is not questioned, as it was once done, and catechism or the "laws of God" are not used, either.O foco deste trabalho está em observar discursos de bispos católicos proferidos em reação à possibilidade de símbolos religiosos serem retirados de estabelecimentos públicos. Para isso, são observadas respostas do Episcopado ao 3º Programa Nacional de Direitos Humanos (PNDH-3), lançado pelo governo federal brasileiro em finais de 2009. Entre os itens do documento, consta a proposta de impedir a ostentação de signos confessionais em recintos da União. Ao analisar os argumentos eclesiásticos, salta aos olhos como a “arma da cultura” é acionada nessa controvérsia. Trata-se de uma abordagem que se distancia dos modelos discursivos historicamente adotados pela Igreja no Brasil. Não se questiona a laicidade do Estado, como era feito outrora, nem se lança mão do catecismo ou das “leis de Deus”