Infraestruturas para localização baseadas em redes sem fios

Mestrado em Engenharia Electrónica e TelecomunicaçõesThe rapid evolution of Wireless technologies, speci cally in the area of Wireless Sensor Networks (WSN), has led to a growing demand for the availability of information anywhere, about anything. WSN are being widely used, for example, in domotic applications, partly due to their relatively low cost and their low energy consumption nature. These characteristics make this kind of networks very useful to ll some gaps in other applications, e.g. localization-related applications. This dissertation focuses, then, on the growing importance and demand for localization of people or objects and presents one of the possible approaches to the problem of indoor localization. By merging two di erent wireless technologies (IEEE 802.11 and IEEE 802.15.4), it is possible to make wireless communications more e cient for some applications. The merge is achieved by the creation of a Gateway, with support for both standards and near-transparent translation between them. This allows cheaper 802.15.4 devices to communicate with regular 802.11 TCP/IP (Transmission Control Protocol/Internet Protocol) based networks, giving space for inumerous applications, speci cally for localization purposes, which is the main goal of this project. The creation of the necessary hardware infrastructures and its respective control software, even though the solution may be used in a large range of applications, is more speci cally directed to comply with some of the requirements of the localization system to be created, eventually. So, in addition to the Gateways that make the translation between the two already referred standards, this project consists in the creation of Tags, small low-power and low-cost end-devices that are to be attached to the objects in need of localization features. These devices communicate with the Gateways by means of an 802.15.4 connection and indirectly advertise their location, by providing the signal strength of the connection. This data is computed and can be accessed in any personal computer with a web browser and a connection to the network.A r apida evolu c~ao das tecnologias de redes sem os, em particular na area das Wireless Sensor Networks (WSN), levou ao crescimento da necessidade de obter informa c~oes, sobre qualquer coisa, em qualquer lugar. As WSN t^em sido amplamente utilizadas, por exemplo, em aplica c~oes da area da dom otica, em parte devido ao seu relativamente baixo custo e baixo consumo de energia. Estas caracter sticas fazem com que este tipo de redes seja bastante importante no preenchimento de algumas lacunas ainda existentes noutras aplica c~oes, como por exemplo, aplica c~oes de localiza c~ao de objectos. Esta disserta c~ao foca-se, ent~ao, na crescente import^ancia e necessidade de localiza c~ao de pessoas e objectos e apresenta uma das poss veis abordagens ao problema de localiza c~ao em espa cos fechados. Atrav es da integra c~ao m utua de duas tecnologias wireless diferentes (IEEE 802.11 e 802.15.4) e poss vel tornar as comunica c~oes wireless bastante mais e cientes em alguns campos de aplica c~ao. Esta integra c~ao e conseguida com a cria c~ao de um Gateway com suporte para ambos os standards referidos e tradu c~ao quase transparente (para o utilizador) entre ambos. Assim, passa a ser poss vel a comunica c~ao entre dispositivos mais baratos (802.15.4) e redes 802.11 baseadas em TCP/IP (Transmission Control Protocol/Internet Protocol), abrindo algum espa co a cria c~ao de in umeras aplica c~oes, mais especi camente, aplica c~oes relacionadas com localiza c~ao, que representam, no fundo, o objectivo principal deste projecto. A cria c~ao das infraestruturas necess arias e do respectivo software de controlo, ainda que esta solu c~ao possa ser aplicada em muitos outros campos, foi direccionada especi camente para cumprir com alguns dos requisitos do sistema de localiza c~ao que venha eventualmente a ser criado. Assim, para al em dos Gateways, que fazem a tradu c~ao entre os dois standards j a mencionados, este projecto consiste na cria c~ao de Tags, pequenos dispositivos terminais de muito baixo custo e muito baixo consumo energ etico, que poder~ao ser acoplados aos objectos que necessitem de localiza c~ao. Estes dispositivos comunicam com os Gate- ways atrav es de uma liga c~ao wireless usando o standard IEEE 802.15.4 e, indirectamente, anunciam a sua localiza c~ao atrav es da disponibiliza c~ao do valor da for ca do sinal na conex~ao. Estas informa c~oes s~ao processadas e podem ser acedidas a partir de qualquer computador pessoal que esteja munido de um browser web e ligado a mesma rede

SafeRegions: performance evaluation of multi-party protocols on HBase

On-line applications and services are now a critical part of our everyday life. Using these services typically requires us to trust our personal or company's information to a large number of third-party entities. These entities enforce several security measures to avoid unauthorized accesses but data is still stored on common database systems that are designed without data privacy concerns in mind. As a result, data is vulnerable against anyone with direct access to the database, which may be external attackers, malicious insiders, spies or even subpoenas. Building strong data privacy mechanisms on top of common database systems is possible but has a significant impact on the system's resources, computational capabilities and performance. Notably, the amount of useful computation that may be done over strongly encrypted data is close to none, which defeats the purpose of offloading computation to third-party services. In this paper, we propose to shift the need to trust in the honesty and security of service providers to simply trust that they will not collude. This is reasonable as cloud providers, being competitors, do not share data among themselves. We focus on NoSQL databases and present SafeRegions, a novel prototype of a distributed and secure NoSQL database that is built on top of HBase and that guarantees strong data privacy while still providing most of HBase's query capabilities. SafeRegions relies on secret sharing and multiparty computation techniques to provide a NoSQL database built on top of multiple, non-colluding service providers that appear as a single one to the user. Strikingly, service providers, individually, cannot disclose any of the user's data but, together, are able to offer data storage and processing capabilities. Additionally, we evaluate SafeRegions exposing performance trade-offs imposed by security mechanisms and provide useful insights for future research on performance optimization

Clouder: a flexible large scale decentralized object store - architecture overview

The current exponential growth of data calls for massive scale capabilities of storage and processing. Such large volumes of data tend to disallow their centralized storage and processing making extensive and flexible data partitioning unavoidable. This is being acknowledged by several major Internet players embracing the Cloud computing model and offering first generation remote storage services with simple processing capabilities. In this position paper we present preliminary ideas for the architecture of a flexible, efficient and dependable fully decentralized object store able to manage very large sets of variable size objects and to coordinate in place processing. Our target are local area large computing facilities composed of tens of thousands of nodes under the same administrative domain. The system should be capable of leveraging massive replication of data to balance read scalability and fault tolerance.(undefined

Clouder : a flexible large scale decentralized object store

Programa Doutoral em Informática MAP-iLarge scale data stores have been initially introduced to support a few concrete extreme scale applications such as social networks. Their scalability and availability requirements often outweigh sacrificing richer data and processing models, and even elementary data consistency. In strong contrast with traditional relational databases (RDBMS), large scale data stores present very simple data models and APIs, lacking most of the established relational data management operations; and relax consistency guarantees, providing eventual consistency. With a number of alternatives now available and mature, there is an increasing willingness to use them in a wider and more diverse spectrum of applications, by skewing the current trade-off towards the needs of common business users, and easing the migration from current RDBMS. This is particularly so when used in the context of a Cloud solution such as in a Platform as a Service (PaaS). This thesis aims at reducing the gap between traditional RDBMS and large scale data stores, by seeking mechanisms to provide additional consistency guarantees and higher level data processing primitives in large scale data stores. The devised mechanisms should not hinder the scalability and dependability of large scale data stores. Regarding, higher level data processing primitives this thesis explores two complementary approaches: by extending data stores with additional operations such as general multi-item operations; and by coupling data stores with other existent processing facilities without hindering scalability. We address this challenges with a new architecture for large scale data stores, efficient multi item access for large scale data stores, and SQL processing atop large scale data stores. The novel architecture allows to find the right trade-offs among flexible usage, efficiency, and fault-tolerance. To efficient support multi item access we extend first generation large scale data store’s data models with tags and a multi-tuple data placement strategy, that allow to efficiently store and retrieve large sets of related data at once. For efficient SQL support atop scalable data stores we devise design modifications to existing relational SQL query engines, allowing them to be distributed. We demonstrate our approaches with running prototypes and extensive experimental evaluation using proper workloads.Os sistemas de armazenamento de dados de grande escala foram inicialmente desenvolvidos para suportar um leque restrito de aplicacões de escala extrema, como as redes sociais. Os requisitos de escalabilidade e elevada disponibilidade levaram a sacrificar modelos de dados e processamento enriquecidos e até a coerência dos dados. Em oposição aos tradicionais sistemas relacionais de gestão de bases de dados (SRGBD), os sistemas de armazenamento de dados de grande escala apresentam modelos de dados e APIs muito simples. Em particular, evidenciasse a ausência de muitas das conhecidas operacões de gestão de dados relacionais e o relaxamento das garantias de coerência, fornecendo coerência futura. Atualmente, com o número de alternativas disponíveis e maduras, existe o crescente interesse em usá-los num maior e diverso leque de aplicacões, orientando o atual compromisso para as necessidades dos típicos clientes empresariais e facilitando a migração a partir das atuais SRGBD. Isto é particularmente importante no contexto de soluções cloud como plataformas como um servic¸o (PaaS). Esta tese tem como objetivo reduzir a diferencça entre os tradicionais SRGDBs e os sistemas de armazenamento de dados de grande escala, procurando mecanismos que providenciem garantias de coerência mais fortes e primitivas com maior capacidade de processamento. Os mecanismos desenvolvidos não devem comprometer a escalabilidade e fiabilidade dos sistemas de armazenamento de dados de grande escala. No que diz respeito às primitivas com maior capacidade de processamento esta tese explora duas abordagens complementares : a extensão de sistemas de armazenamento de dados de grande escala com operacões genéricas de multi objeto e a junção dos sistemas de armazenamento de dados de grande escala com mecanismos existentes de processamento e interrogac¸ ˜ao de dados, sem colocar em causa a escalabilidade dos mesmos. Para isso apresent´amos uma nova arquitetura para os sistemas de armazenamento de dados de grande escala, acesso eficiente a m´ultiplos objetos, e processamento de SQL sobre sistemas de armazenamento de dados de grande escala. A nova arquitetura permite encontrar os compromissos adequados entre flexibilidade, eficiˆencia e tolerˆancia a faltas. De forma a suportar de forma eficiente o acesso a m´ultiplos objetos estendemos o modelo de dados de sistemas de armazenamento de dados de grande escala da primeira gerac¸ ˜ao com palavras-chave e definimos uma estrat´egia de colocac¸ ˜ao de dados para m´ultiplos objetos que permite de forma eficiente armazenar e obter grandes quantidades de dados de uma s´o vez. Para o suporte eficiente de SQL sobre sistemas de armazenamento de dados de grande escala, analisámos a arquitetura dos motores de interrogação de SRGBDs e fizemos alterações que permitem que sejam distribuídos. As abordagens propostas são demonstradas através de protótipos e uma avaliacão experimental exaustiva recorrendo a cargas adequadas baseadas em aplicações reais

Projeto de suporte de carga para robôs móveis autónomos de transporte cooperativo

Dissertação de mestrado integrado em Engenharia MecânicaO transporte coletivo por equipas de robôs móveis autónomos é uma configuração vantajosa quando os objetos a transportar são de elevadas dimensões e quando o ambiente de trabalho apresenta obstáculos a contornar. Tendo este princípio como base do projeto que se apresenta, desenvolveu-se na Universidade do Minho, numa parceria entre o Departamento de Engenharia Mecânica e o Departamento de Eletrónica Industrial, um sistema de suporte de carga com a finalidade de ser implementado numa esquipa de robôs móveis autónomos desenvolvida no Mobile and Anthropomorphic Robotics Lab do Departamento de Eletrónica Industrial. Este sistema de suporte de carga permite à equipa de robôs transportarem uma carga, mantendo a estabilidade da posição da carga, através da compensação de quaisquer desvios que possam surgir devido a manobras efetuadas pela equipa de robôs. Pretende-se com o presente trabalho criar um conceito capaz de ser verificável a nível de protótipo que posteriormente possa ser escalado de modo a suportar cargas superiores às que atualmente terá de suportar.The cooperative load transportation by a team of mobile robots is an advantageous configuration when the loads to transport have big dimensions, have complex shapes and when the workspace presents obstacles that the robots or team of robots must be able to avoid. Having this concept as a basis of the current project, it was developed in Universidade do Minho, in a partnership between the departments of Mechanical and Electronical Engineering, a system for load support with the goal of being implemented on a team of autonomous mobile robots developed in the Mobile and Anthropomorphic Robotics Lab of the Department of Electronical Engineering. This load support system allows the robot team to transport a load, assuring the stability of the said load, this is achieved by counteracting any deviations by the load from a central point, caused by the robot team’s maneuvers

A correlation-aware data placement strategy for key-value stores

Key-value stores hold the unprecedented bulk of the data produced by applications such as social networks. Their scalability and availability requirements often outweigh sacri cing richer data and pro- cessing models, and even elementary data consistency. Moreover, existing key-value stores have only random or order based placement strategies. In this paper we exploit arbitrary data relations easily expressed by the application to foster data locality and improve the performance of com- plex queries common in social network read-intensive workloads. We present a novel data placement strategy, supporting dynamic tags, based on multidimensional locality-preserving mappings. We compare our data placement strategy with the ones used in existing key-value stores under the workload of a typical social network appli- cation and show that the proposed correlation-aware data placement strategy o ers a major improvement on the system's overall response time and network requirements

Sexualidade de alunos/as cegos/as: uma curta metragem como recurso pedagógico na formação de professores/as

O objetivo deste trabalho é descrever os efeitos do uso de uma curta-metragem como uma estratégia pedagógica para sensibilizar e fomentar questões num processo de formação continua de educadores/as sobre a educação em sexualidade e deficiências. A educação em sexualidade é um conteúdo necessário na formação integral de todos/as os/as alunos/as. Entretanto, muitos/as professores/as têm dificuldades pessoais ou falta de formação específica para assumir essa tarefa, sobretudo, quando entre os/as alunos/as há uma deficiência, por isso, recorrem à formação continua. Propomos, então, a utilização da curta-metragem brasileira chamada Hoje Eu Não Quero Voltar Sozinho (Daniel Ribeiro) que aborda as descobertas afetivas homossexuais de um adolescente cego. A proposta pedagógica a partir do filme baseia-se na pedagogia histórico-crítica, o que significa promover a reflexão crítica sobre a: prática social inicial, problematização, instrumentalização, catarse e prática social qualitativamente distinta. Esta proposta pedagógica incentiva a reflexão entre os/as professores/as sobre os valores pessoais e os padrões definidores de normalidade e coloca a deficiência como uma condição que não aparece como impeditiva das vivencias afetivas e sexuais na adolescência. Este filme é um recurso que sensibiliza os/as educadores/as para a temática e os/as instrumentaliza teoricamente sobre temas como inclusão, socialização, autonomia, estereótipos da sexualidade de pessoas com deficiência, homoerotismo, conflitos subjetivos e sociais na adolescência, etc. Conclui-se que este vídeo é um recurso interessante nos processos de formação docente, pois convida o/a educador/a a reconhecer as suas próprias dificuldades diante de temas como adolescência, deficiência, sexualidade e homossexualidade. Além disso, a narrativa neste filme considera o desenvolvimento integral da pessoa com deficiência, favorecendo, assim, a formação critica de educadores /formadores que é imprescindível numa sociedade inclusiva.The aim of this paper is to describe the effects of the use of a short film as a pedagogical strategy to raise awareness and to foster issues in an in-service teacher-training course on sexuality education and disabilities. Sexuality education is a necessary content in the integral formation of all students. However, many teachers have personal difficulties or lack of specific training to take on this task, especially when there is a disability among students, therefore they resort to in-service teacher training. Therefore, in this research it was proposed to use the Brazilian short film called Today I Do not Want to Go Back Alone (by Daniel Ribeiro) that approaches the affective homosexuals discoveries of a blind adolescent. The pedagogical proposal based on this film was focused on the historical-critical pedagogy, which means that it was promoted critical reflection on the: initial social practice, problematization, instrumentalization, catharsis and qualitatively different social practice. This pedagogical proposal encourages the reflection among teachers about personal values and the standards that define the normality and places disability as a condition that does not appear as an impediment to the affective and sexual experiences in adolescence. This film is a resource that sensitizes educators to this theme and provides them theoretical tools on topics such as inclusion, socialization, autonomy, and stereotypes of the sexuality of people with disabilities, homoeroticism, and subjective and social conflicts in adolescence, etc. It is concluded that this video is an interesting resource in the processes of teacher training, because it invites the educator to recognize their own difficulties in relation to themes such as adolescence, disability, sexuality and homosexuality. In addition, the narrative in this film considers the integral development of the disabled individuals, thus favouring the critical formation of educators / trainers that is essential in an inclusive society.CIEC - Centro de Investigação em Estudos da Criança, IE, UMinho (UI 317 da FCT), PortugalFinanciado por Fundos Nacionais através da FCT (Fundação para a Ciência e a Tecnologia) e cofinanciado pelo Fundo Europeu de Desenvolvimento Regional (FEDER) através do COMPETE 2020 – Programa Operacional Competitividade e Internacionalização (POCI) no âmbito do CIEC (Centro de Investigação em Estudos da Criança da Universidade do Minho) com a referência POCI-01-0145-FEDER-007562info:eu-repo/semantics/publishedVersio

d'Artagnan: a trusted NoSQL database on untrusted clouds

Privacy sensitive applications that store confidential information such as personal identifiable data or medical records have strict security concerns. These concerns hinder the adoption of the cloud. With cloud providers under the constant threat of malicious attacks, a single successful breach is sufficient to exploit any valuable information and disclose sensitive data. Existing privacy-aware databases mitigate some of these concerns, but sill leak critical information that can potently compromise the entire system's security. This paper proposes d'Artagnan, the first privacy-aware multi-cloud NoSQL database framework that renders database leaks worthless. The framework stores data as encrypted secrets in multiple clouds such that i) a single data breach cannot break the database's confidentiality and ii) queries are processed on the server-side without leaking any sensitive information. d'Artagnan is evaluated with industry-standard benchmark on market-leading cloud providers.This work is financed by National Funds through thePortuguese funding agency, FCT - Fundação para a Ciência ea Tecnologia within project: UID/EEA/50014/2019. This workis financed by National Funds through the Portuguese fundingagency, FCT - Fundação para a Ciência e a Tecnologia withthe grant: SFRH/BD/142704/201

Automatic elasticity in OpenStack

Cloud computing infrastructures are the most recent ap- proach to the development and conception of computational systems. Cloud infrastructures are complex environments with various subsystems, each one with their own challenges. Cloud systems should be able to provide the following fun- damental property: elasticity. Elasticity is the ability to automatically add and remove instances according to the needs of the system. This is an requirement for pay-per-use billing models. Various open source software solutions allow companies and institutions to build their own Cloud infrastructure. How- ever, in most of these, the elasticity feature is quite imma- ture. Monitoring and timely adapting the active resources of a Cloud computing infrastructure is key to provide the elasticity required by diverse, multi tenant and pay-per-use business models. In this paper, we propose Elastack, an automated monitor- ing and adaptive system, generic enough to be applied to existing IaaS frameworks and intended to enable the elastic- ity they currently lack. Our approach offers any Cloud in- frastructure the mechanisms to implement automated mon- itoring and adaptation as well as the flexibility to go beyond these. We evaluate Elastack by integrating it with the Open- Stack and showing how easy it is to add these important features with a minimum, almost imperceptible, amount of modifications to the default installation.(undefined

Workload-aware table splitting for NoSQL

Massive scale data stores, which exhibit highly desirable scalability and availability properties are becoming pivotal systems in nowadays infrastructures. Scalability achieved by these data stores is anchored on data independence; there is no clear relationship between data, and atomic inter-node operations are not a concern. Such assumption over data allows aggressive data partitioning. In particular, data tables are horizontally partitioned and spread across nodes for load balancing. However, in current versions of these data stores, partitioning is either a manual process or automated but simply based on table size. We argue that size based partitioning does not lead to acceptable load balancing as it ignores data access patterns, namely data hotspots. Moreover, manual data partitioning is cumbersome and typically infeasible in large scale scenarios. In this paper we propose an automated table splitting mechanism that takes into account the system workload. We evaluate such mechanism showing that it simple, non-intrusive and effective