Heading towards the era of Internet-of-things (IoT) means both opportunity and challenge for the circuit-design community. In a system where billions of devices are equipped with the ability to sense, compute, communicate with each other and perform tasks in a coordinated manner, security and power management are among the most critical challenges. Physically unclonable function (PUF) emerges as an important security primitive in hardware-security applications; it provides an object-specific physical identifier hidden within the intrinsic device variations, which is hard to expose and reproduce by adversaries. Yet, designing a compact PUF robust to noise, temperature and voltage remains a challenge. This thesis presents a novel PUF design approach based on a pair of ultra-compact analog circuits whose output is proportional to absolute temperature. The proposed approach is demonstrated through two works: (1) an ultra-compact and robust PUF based on voltage-compensated proportional-to-absolute-temperature voltage generators that occupies 8.3× less area than the previous work with the similar robustness and twice the robustness of the previously most compact PUF design and (2) a technique to transform a 6T-SRAM array into a robust analog PUF with minimal overhead. In this work, similar circuit topology is used to transform a preexisting on-chip SRAM into a PUF, which further reduces the area in (1) with no robustness penalty. In this thesis, we also explore techniques for power management circuit design. Energy harvesting is an essential functionality in an IoT sensor node, where battery replacement is cost-prohibitive or impractical. Yet, existing energy-harvesting power management units (EH PMU) suffer from efficiency loss in the two-step voltage conversion: harvester-to-battery and battery-to-load. We propose an EH PMU architecture with hybrid energy storage, where a capacitor is introduced in addition to the battery to serve as an intermediate energy buffer to minimize the battery involvement in the system energy flow. Test-case measurements show as much as a 2.2× improvement in the end-to-end energy efficiency. In contrast, with the drastically reduced power consumption of IoT nodes that operates in the sub-threshold regime, adaptive dynamic voltage scaling (DVS) for supply-voltage margin removal, fully on-chip integration and high power conversion efficiency (PCE) are required in PMU designs. We present a PMU–load co-design based on a fully integrated switched-capacitor DC-DC converter (SC-DC) and hybrid error/replica-based regulation for a fully digital PMU control. The PMU is integrated with a neural spike processor (NSP) that achieves a record-low power consumption of 0.61 µW for 96 channels. A tunable replica circuit is added to assist the error regulation and prevent loss of regulation. With automatic energy-robustness co-optimization, the PMU can set the SC-DC’s optimal conversion ratio and switching frequency. The PMU achieves a PCE of 77.7% (72.2%) at VIN = 0.6 V (1 V) and at the NSP’s margin-free operating point.

A Internet das coisas é constituída de objetos que possuem pequenos sensores e atuadores capazes de interagir com o ambiente. Tais objetos ou coisas estão interconectados entre si e com acesso à Internet por meio de redes com e sem fio. A combinação entre os dispositivos embarcados com sensores e o acesso à Internet possibilita a comunicação dos recursos do mundo físico com o espaço cibernético, desempenhando um papel fundamental na resolução de muitos desafios encontrados na sociedade atual. Porém, a maioria das aplicações existentes são dedicadas a resolver problemas específicos utilizando tais recursos apenas em redes internas, limitando a real capacidade da Internet das Coisas. Diversos trabalhos na literatura propõem a reutilização de tais recursos em forma de serviço por meio de modelos como Dados como Serviço e Sensoriamento como Serviço. Neste contexto, em que potencialmente milhares de recursos podem transferir dados semelhantes de aplicações diferentes, a utilização de técnicas que possam selecionar recursos de forma sensível a contexto torna-se imprescindível. Nesta tese são propostos um conjunto de métodos para melhorar a relação custo-benefício na seleção de recursos em ambientes IoT, auxiliando na tomada de decisão durante a seleção dos recursos que serão ofertados como serviço. Os resultados obtidos por meio de estudos de caso, permitiram a comparação da qualidade da solução e do custo computacional das técnicas aplicadas na seleção de recursos em ambientes IoT, bem como o desenvolvimento de duas novas técnicas para a seleção de recursos, denominadas Elimination Sort e Fast Elimination Sort. / The Internet of Things is composed of objects which have small sensors and actuators capable of interacting with the environment. Such objects or things are interconnected with each other and has access to the Internet through wired and wireless networks. The combination of embedded devices with sensors and access to the Internet become it possible to communicate the resources of the physical world with the cyberspace, playing a key role in solving many challenges found in todays society. However, most existing applications solves a specific problem using its resources just for own purpose, limiting the actual ability of the Internet of Things. Several works propose the reuse of such resources through service models such as Data as Service and Sensing as a Service. In this context, where thousands of resources can transfer similar data from different applications, the use of techniques that can select these features in a context-sensitive way becomes essential. In this thesis, a set of methods to improve the cost-benefit of the process of selection of resources in IoT environments is proposed to support the decision making during resource selection that will be offered as a service. The results obtained through a case study allowed the comparison of the solution quality and the computational cost of the techniques applied for resource selection in IoT environments, as well as the development of two new techniques for the selection of resources called Elimination Sort and Fast Elimination Sort.

Les défis que l'Internet des objets posent sont à la mesure des transformations que cette technologie est susceptible d'entraîner dans notre rapport quotidien à notre environnement. Nos propres objets, et des milliards d'autres, disposeront de capacités de traitement des données et de connexion au réseau, certes limitées mais effectives. Alors, ces objets se doteront d'une dimension numérique, et deviendront accessibles d'un façon tout à fait nouvelle. Ce n'est pas seulement la promesse d'un accès original à l'objet, mais bel et bien l'avènement d'une nouvelle perception et interaction avec ce qui nous entoure. Les applications de l'Informatique ubiquitaire utiliseront majoritairement les interactions entre objets, et la somme de leurs actions/réactions offrira une véritable valeur ajoutée. Mais l'hétérogénéité des composants matériels et des réseaux empruntés freine considérablement l'essor de l'Internet des objets. L'objectif de cette thèse est de proposer une solution effective et le cadre nécessaire à la construction de telles applications. Après avoir montré la pertinence des solutions chorégraphiées et quantifié le gain acquis sur des structures de communication arborescentes, nous présenterons D-LITe, notre framework, qui appréhende chaque objet comme étant fournisseur de services. Grâce à son approche REST assurant l'interopérabilité dans l'assortiment des composants et réseaux de l'Internet des objets, le framework D-LITe, hébergé par chaque objet (et adapté à ses contraintes), fournit un contrôle distant, aussi bien pour sa reprogrammation dynamique que les échanges avec ses partenaires. Nous poursuivrons en présentant SALT, le langage de programmation compris par D-LITe, basé sur les transducteurs à états fini. Outre son expressivité étendue aux particularités du domaine, SALT accorde un accès aux fonctionnalités de l'objet au travers d'une couche d'abstraction matérielle. Enfin, profitant de la standardisation offerte par D-LITe pour la programmation de chaque composant en particulier, une solution de composition, BeC3, va offrir un moyen efficace pour construire une application complète par assemblage des comportement distribués, tout en respectant la cohérence des interactions entre objets, par l'intermédiaire d'une abstraction des échanges et de leur modélisation. Aussi sommes-nous, par la résolution des problématiques rencontrées à chacun des différents niveaux, capables de présenter une solution simple, cohérente et fonctionnelle à même de bâtir réellement et efficacement des applications robustes pour l'Internet des objets / The challenges which the Internet of objects put are for the measure of the transformations which this technology may pull in our daily report to our environment. Our own objects, and billions of others, will have processing capacities of the data and connection to the network, certainly limited but effective. Then, these objects will be equipped with a digital dimension, and will become accessible in a completely new way. It is not only the promise of an original access to the object, but well and truly the succession of a new perception and an interaction with what what surrounds us. The applications of the ubiquitaire Computing will use mainly the interactions between objects, and the sum of their actions / reactions will offer a real added value

O crescente interesse pela caracterização de parâmetros acústicos marinhos esbarra nos poucos dispositivos eletrônicos que permitem capturar, armazenar, processar e difundir dados. Os equipamentos atuais que possibilitam obter dados referentes à vida marinha e permitem estudar as influências humanas sobre ela possuem alto custo e funcionam de forma isolada, ou seja, normalmente não há comunicação com outros dispositivos, o que dificulta a monitorização de eventos em tempo real. Sendo assim, neste trabalho são revisadas as características necessárias para estabelecer uma rede de sensores sem fio (RSSF) de alta confiabilidade, utilizando-se o conceito de Internet das Coisas (IoT). São comparados os protocolos MQTT-SN e CoAP com ferramentas de simulação e implementada uma rede de sensoriamento acústico aquático constituída de três nós sensores autônomos e um gateway usando o protocolo 6LowPAN. Também é implementada a tradução para o protocolo IPV4 no gateway, de modo que o funcionamento da rede de sensores pode ser monitorada num servidor remoto na Internet em tempo real. O desempenho da rede é avaliado com relação à autonomia energética, capacidade de memória, alcance e confiabilidade na entrega dos dados. As unidades autônomas desenvolvidas podem operar ininterruptamente, com uso de baterias, por aproximadamente 125 horas com memória de gravação de 48GB e alcance de 100m aproximadamente. Por fim, é implementado o pré-processamento dos dados sonoros visando a detecção de eventos acústicos aquáticos. / The increasing interest in the characterization of marine acoustic parameters needs electronic devices that allow capture, store, process, and diffuse data. Current equipment that provides data about the marine life and allow the study of human influences on it have high cost and work isolated, that is, without communication with other devices, which makes it difficult to monitor events in real time. Therefore, this work revises the necessary features to establish a high reliability wireless sensor network (WSN) by applying the concept of Internet of Things (IoT). The protocols MQTT-SN and CoAP are compared with simulation tools and a network is implemented to sense acoustic signals, composed by three autonomous sensor nodes and a gateway using the protocol 6LowPAN. The translation for the IPV4 protocol in the gateway is also implemented, so the operation of the sensor network can be monitored by a remote server on the Internet in real time. The performance of the network is evaluated in relation to power autonomy, memory capacity, reach and reliability. The autonomous sensor nodes can operate uninterrupted, with use of batteries, for approximately 125 hours with 48GB storage for recording and approximately 100m range. Finally, data pre-processing is implemented in order to detect aquatic acoustic events.

Made available in DSpace on 2016-04-29T14:23:40Z (GMT). No. of bitstreams: 1 Claudir Segura.pdf: 8676891 bytes, checksum: a3e326477f3d953dcccce50dae88afa0 (MD5) Previous issue date: 2015-11-16 / A new era where smartphones pay bills, households, industries and buildings, industries production sensors control the flow of energy and water . Doctors can monitor health of their patients remotely, and designers can animate characters with their own movements. This new era of connections between multiple devices, receiving and sending data over the Internet is what we call the Internet of Things, English translation of The Internet of Things The objective of this study is to problematize the Internet of Things and its application under the philosophy of the Design Thinking and how the consumption paradigms are broken from that intervention. We see that in this new technological step man s participation in the process is of vital importance to the growth and application of the IoT. This is not just a case to create an interface for the user to interact. It is to create contact points for enriching the user experience and consequently a more tailored application to his need and also to list possible interdisciplinary areas studied here / Uma nova era onde celulares pagam contas, residências, indústrias e prédios, munidos e sensores controlam produção o fluxo de energia e de água até médicos monitoram a saúde de seus pacientes remotamente, e designers animam personagens com seus próprios movimentos. Essa nova era de conexões entre múltiplos dispositivos, recebendo e enviando dados pela Internet é o que chamamos de Internet das Coisas, tradução do inglês de Internet of Things. O objetivo deste trabalho é problematizar a Internet das Coisas e sua aplicação sob a filosofia do Design Thinking e de que maneira os paradigmas do consumo serão quebrados a partir dessa intervenção. Vemos que nessa nova etapa tecnológica a participação do homem no processo é de vital importância para o crescimento e aplicação da IoT. Não se trata apenas de se criar uma interface para que o usuário possa interagir. Trata-se de se criar pontos de contato para o enriquecimento da experiência do usuário e consequentemente obter uma aplicação mais adaptada a sua necessidade e ainda elencar a possível interdisciplinaridade entre as áreas aqui estudadasiplinaridade

Algumas palavras e definições comumente utilizadas quando se está falando de Software-Defined Networking, como programabilidade, flexibilidade, ou gerenciamento centralizado, parecem muito apropriadas ao contexto de um outro paradigma de rede: Internet of Things. Em redes domésticas já não é incomum a existência de dispositivos projetados para segurança, climatização, iluminação, monitoramento de saúde e algumas formas de automação que diferem entre si em diversos aspectos, como no modo de operar e de se comunicar. Lidar com este tipo de cenário, que pode diferir bastante daquilo que estamos acostumados na gerência de redes e serviços, fazendo uso dos recursos tradicionais como ferramentas e protocolos bem estabelecidos, pode ser difícil e, em alguns casos, inviável. Com o objetivo de possibilitar o monitoramento remoto de pacientes com doenças crônicas através de dispositivos de healthcare disponíveis no mercado, uma proposta de middleware foi desenvolvida em um projeto de pesquisa para contornar as limitações relacionadas à interoperabilidade, coleta de dados, gerência, segurança e privacidade encontradas nos dispositivos utilizados. O middleware foi projetado com o intuito de executar em access points instalados na casa dos pacientes. Contudo, as limitações de hardware e software do access point utilizado refletem no desenvolvimento, pois restringem o uso de linguagens de programação e recursos que poderiam agilizar e facilitar a implementação dos módulos e dos mecanismos necessários. Os contratempos encontrados no desenvolvimento motivaram a busca por alternativas, o que resultou na refatoração do middleware através de Software-Defined Networking, baseando-se em trabalhos que exploram o uso desse paradigma em redes domésticas. O objetivo deste trabalho é verificar a viabilidade da utilização de Software-Defined Networking no contexto de Internet of Things, mais especificamente, aplicado ao serviço de monitoramento de pacientes da proposta anterior e explorar os possíveis benefícios resultantes. Com a refatoração, a maior parte da carga de serviços da rede e do monitoramento foi distribuída entre servidores remotos dedicados, com isso os desenvolvedores podem ir além das restrições do access point e fazer uso de recursos antes não disponíveis, o que potencializa um processo de desenvolvimento mais ágil e com funcionalidades mais complexas, ampliando as possibilidades do serviço. Adicionalmente, a utilização de Software-Defined Networking proporcionou a entrega de mais de um serviço através de um único access point, escalabilidade e autonomia no gerenciamento das redes e dos dispositivos e na implantação de serviços, fazendo uso de recursos do protocolo OpenFlow, e a cooperação entre dispositivos e serviços a fim de se criar uma representação digital mais ampla do ambiente monitorado. / Some words and definitions usually employed when talking about Software-Defined Networking such as programmability, frexibility, or centralized management sound very appropriate to the context of another network paradigm: Internet of Things. The presence of devices designed for security, air conditioning, lighting, health monitoring and some other automation resources have become common in home networks; those devices may be different in many ways, such as the way they operate and communicate, between others. Dealing with this kind of scenario may differ in many ways from what we are familiar regarding networking and services management; the use of traditional management tools and protocols may be hard or even unfeasible. Aiming to enable the health monitoring of patients with chronical illnesses through using off-the-shelf healthcare devices a middleware proposal was developed in a research project to circumvent interoperability, data collecting, management, security and privacy issues found in employed devices. The middleware was designed to run on access points in the homes of the patients. Although hardware and software limitations of the used access points reflect on the development process, because they restrict the use of programming languages and resources that could be employed to expedite the implementation of necessary modules and features. Development related mishaps have motivated the search for alternatives resulting in the middleware refactoring through Software-Defined Networking, based on previous works where that paradigm is used in home networks. This work aims to verify the feasability of the employment of Software- Defined Networking in the Internet of Things context, and its resulting benefits; specifically in the health monitoring of chronic patients service from the previous proposal. After refactoring most of the network and services load was distributed among remote dedicated servers allowing developers to go beyond the limitations imposed by access points constraints, and to make use of resources not available before enabling agility to the development process; it also enables the development of more complex features expanding services possibilities. Additionally Software-Defined Networking employment provides benefits such as the delivering of more than only one service through the same access point; scalability and autonomy to the network and devices monitoring, as to the service deployment through the use of OpenFlow resources; and devices and services cooperation enabling the built of a wider digital representation of the monitored environment.

Wireless sensor networks are often battery powered and therefore their power consumption is of critical importance. Power requirements can be reduced by switching off radios when they are not needed and by using multi-hop communications to reduce the length of the radio links. Multi-hop communications however require message routing through the network. The Routing Protocol for lossy networks (RPL) has been designed by the Internet Engineering Task Force (IETF) for seamless integration of wireless sensor networks in the Internet. For switching on and off radios, radio duty cycling (RDC) protocols have been added to the traditional medium access control (MAC) protocols. Despite the fact they belong to different layers in the communications stack, it is intuitively clear that the choice of a specific RDC protocol for saving energy can influence the performances of RPL. Exploring experimentally this influence was the initial goal of this research. A 25 nodes wireless sensor network using Zolertia Z1 motes and the Contiki software was used for this investigation. Performance measurements without RDC protocol and with the three different RDC protocols readily available in Contiki were organized and the results of the experiments were compared. Unfortunately, with all three RDC protocols, serious malfunctions obscured the experimental results. Those malfunctions did not show up in absence of a RDC protocol and they could not be reproduced by our simulation studies. To tackle this issue, the behavior of the RDC protocols was scrutinized by means of experimental set-ups that eliminated as much as possible all non RDC related issues. Many, quite varied, malfunctions were discovered which all could have caused the observed RPL issues. Further research and better experimental set-ups made clear that all the discovered RDC malfunctions could be attributed to two real-world facts that were not considered by the implementers of the Contiki RDC protocols. The first cause is the small frequency difference between hardware real time clocks in stand-alone motes. The second is that the threshold built in the receiver to detect radio activity is much higher than the minimum level of signal that the same receiver can decode. Work-arounds have been designed for the observed malfunctions and they have been tested by means of a systematic comparison of the performance of the three modified RDC protocols. / Doctorat en Sciences de l'ingénieur et technologie / info:eu-repo/semantics/nonPublished

This is a practice-based research thesis situated in the research context of the 'Internet of Things', and critiques contemporary theoretical discourse related to the 21st century turn of connecting everyday objects to the World Wide Web. In the last decade we have seen the 'Internet of Things' articulated predominately through three commercial design fictions, each a response to the shift towards pervasive", "ubiquitous" (Weiser 1991), or "context-ware" (Schilit, 1994) computing; where we inhabit spaces with objects capable of sensing, recording and relaying data about themselves and their environments. Through reflecting upon these existing design fictions, through a new combination of theories and practice-based research that embodies them, this thesis proposes a recovery to understanding the role of objects in the 'Internet of Things', which this author believes has been lost since its conception in the mid 2000s. In 2000, HP Labs presented Cooltown, which addressed what HP identified as the 'convergence of Web technology, wireless networks, and portable client devices provides'. Cooltown's primary discourse was to provide 'new design opportunities for computer/communications systems, through an infrastructure to support "web presence" for people, places and things.' (Anders 1998; Barton & Kindberg 2002). IBM's Smarter Planet followed this in 2008 and shifted importance from the act of connecting objects to understanding the value of data as it flows between these objects in a network (Castells 1996; Sterling 2005; Latour 2005). Finally, Cisco presented The Internet of Everything in 2012 and moved the argument on one stage further, identifying that the importance of connected objects lies in the sum of their communication across silos of networks, where data can provide potential insight from which you can improve services (Bleecker 2006). Despite these design and theoretical fictions, the affordances of the Internet of Things first proposed in the mid 2000s has regressed from data to product, driven largely by unchanged discourse argued by those designers at its conception and also the enticement of being the next Google acquisition; instead of pigeons reporting on the environmental conditions of a city (Da Costa 2006), we have thermostats controllable from your smartphone (www.scottishpower.co.uk/connect). Therefore the aim of this thesis is to re-examine the initial potential of the Internet of Things, which is tested through a series of design interventions as research for art and design, (produced as part of my EPSRC funded doctoral studies on the Tales of Things and Electronic Memory research project and also whilst employed as a research assistant on two EPSRC funded research programmes of work Sixth Sense Transport, and The Connected High Street), to understand how we use data to allow an alternative discourse to emerge in order to recover the role of a networked object, rather than producing prototypical systems.

abstract: Internet of Things (IoT) is emerging as part of the infrastructures for advancing a large variety of applications involving connections of many intelligent devices, leading to smart communities. Due to the severe limitation of the computing resources of IoT devices, it is common to offload tasks of various applications requiring substantial computing resources to computing systems with sufficient computing resources, such as servers, cloud systems, and/or data centers for processing. However, this offloading method suffers from both high latency and network congestion in the IoT infrastructures. Recently edge computing has emerged to reduce the negative impacts of tasks offloading to remote computing systems. As edge computing is in close proximity to IoT devices, it can reduce the latency of task offloading and reduce network congestion. Yet, edge computing has its drawbacks, such as the limited computing resources of some edge computing devices and the unbalanced loads among these devices. In order to effectively explore the potential of edge computing to support IoT applications, it is necessary to have efficient task management and load balancing in edge computing networks. In this dissertation research, an approach is presented to periodically distributing tasks within the edge computing network while satisfying the quality-of-service (QoS) requirements of tasks. The QoS requirements include task completion deadline and security requirement. The approach aims to maximize the number of tasks that can be accommodated in the edge computing network, with consideration of tasks’ priorities. The goal is achieved through the joint optimization of the computing resource allocation and network bandwidth provisioning. Evaluation results show the improvement of the approach in increasing the number of tasks that can be accommodated in the edge computing network and the efficiency in resource utilization. / Dissertation/Thesis / Doctoral Dissertation Computer Engineering 2018

abstract: Machine learning tutorials often employ an application and runtime specific solution for a given problem in which users are expected to have a broad understanding of data analysis and software programming. This thesis focuses on designing and implementing a new, hands-on approach to teaching machine learning by streamlining the process of generating Inertial Movement Unit (IMU) data from multirotor flight sessions, training a linear classifier, and applying said classifier to solve Multi-rotor Activity Recognition (MAR) problems in an online lab setting. MAR labs leverage cloud computing and data storage technologies to host a versatile environment capable of logging, orchestrating, and visualizing the solution for an MAR problem through a user interface. MAR labs extends Arizona State University’s Visual IoT/Robotics Programming Language Environment (VIPLE) as a control platform for multi-rotors used in data collection. VIPLE is a platform developed for teaching computational thinking, visual programming, Internet of Things (IoT) and robotics application development. As a part of this education platform, this work also develops a 3D simulator capable of simulating the programmable behaviors of a robot within a maze environment and builds a physical quadrotor for use in MAR lab experiments. / Dissertation/Thesis / Masters Thesis Computer Science 2018