IEEE 802.11ah is designed to support battery powered devices that are required to serve for several years in the Internet of Things networks. The Restricted Access Window (RAW) has been introduced in IEEE 802.11ah to address the scalability of thousands of densely deployed devices. As the RAW sizes entail the consumed energy to support the transmitting devices in the network, hence the control mechanism for RAW should be carefully devised for improving the overall energy e ciency of IEEE 802.11ah. This thesis presents a two-stage adaptive RAW scheme for IEEE 802.11ah to optimise the energy efficiency of massive channel access and transmission in the uplink communications for highly dense networks. The proposed scheme adaptively controls the RAW sizes and device transmission access by taking into account the number of devices per RAW, retransmission mechanism, harvested-energy and prioritised access. The scheme has four completely novel control blocks: RAW size control that adaptively adjusts the RAW sizes according to different number of devices and application types in the networks. RAW retransmission control that improves the channel utilisation by retransmitting the collided packets at the subsequent slot in the same RAW. Harvested-energy powered access control that adjusts the RAW sizes with the consideration of the uncertain amount of harvested-energy in each device and channel conditions. Priority-aware channel access control that reduces the collisions of high-priority packets in the time-critical networks. The performance of the proposed controls is evaluated in Matlab under different net work scenarios. Simulation results show that the proposed controls improve the network performances in terms of energy efficiency, packet delivery ratio and delay as compared to the existing window control.

The TV white space (TVWS) is one of the promising technologies to provide wide coverage, energy effcient and cost effective Internet of Things (IoT) services. However, its low operating frequency and wide bandwidth poses significant challenges to antenna designs. In this thesis, three antennas are developed using the characteristic mode analysis (CMA) for IoT devices operating over the TVWS. First, a very-low profile circular small antenna is transformed from a vertical monopole antenna. The CMA is used to determine the mode to be excited and to design a specific feeding structure. After being printed on Rogers 5880 substrate, the final antenna structure operates at 474 MHz with a V SWR < 2 bandwidth of 2.2 MHz. Its lateral radius is just 5.2% of the wavelength of its resonant frequency. Second, a compact U-shaped printed UWB monopole antenna is proposed to operate over the entire UHF TV spectrum. This antenna measures 0:36 0 0:06 0 0:01 0 where 0 is the wavelength of its lowest operating frequency. Its V SWR < 2 bandwidth is 87.5%, and the UWB behaviour is discussed by the CMA. Third, a novel antenna design method is established on annular ring-shaped structures with modal characteristics revealed by the CMA. Following the proposed method, another UWB antenna is achieved by creating and exciting multiple modes with resonant frequencies distributed across the UHF TV spectrum. All antenna designs are verified thorough simulations and measurements. Furthermore, antennas are also integrated into IoT devices and their system performance is measured under different communication scenarios. The system measurements also verify the good propagation property and the abundant spectrum resource of the TVWS.

Submitted by Filipe dos Santos (fsantos@pucsp.br) on 2016-11-24T13:11:59Z No. of bitstreams: 1 Grazielle Bruscato Portella.pdf: 33160644 bytes, checksum: 4b1812b0d96f747cba5575c64bcd1b1e (MD5) / Made available in DSpace on 2016-11-24T13:11:59Z (GMT). No. of bitstreams: 1 Grazielle Bruscato Portella.pdf: 33160644 bytes, checksum: 4b1812b0d96f747cba5575c64bcd1b1e (MD5) Previous issue date: 2016-09-01 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This research proposes a study of Tangible User Interfaces as a digital means of communication, from its conception to the moment of interaction. It poses a historical overview on the evolution of digital interfaces, from the first Graphical User Interfaces to birth of the Internet of Things, emerging phenomenon in the digital media that tangibilizes the information to connected devices. The study also investigates methods for analysis and design of Graphical Interfaces from the point of view of interaction and aesthetics. Attributes from these methods are used to propose a methodology when designing Tangible Interfaces, where its principles are combined in addition to usability and handling aspects, concepts used in Product Design methods. In order to deepen this investigation, three experimental projects from the academic field were selected to analyse the design of assorted Tangible Interfaces and apply the proposed protocol: inFORM (http://tangible.media.mit.edu/project/inform/), a multi-touch interface that addresses remote and tactile communication processes; Daily Stack (https://vimeo.com/10458491/), which works as a means by which the user arranges abstract tasks through physical blocks connected to a software; and ZeroN (http://tangible.media.mit.edu/project/zeron-levitated-interaction-element/), which explores the user-machine interaction through levitation, questioning the object as an speculative medium of interaction. As conclusions, Tangible Interfaces until need to solve some challenges such as resolution, scale and cost before we expect a complete adoption by the public. On the other hand, they can allow a richer physical interaction than Graphical User Interfaces, helping users on its manipulation without the need to have a screen present during all interactions / Esta investigação propõe um estudo sobre a Interface Tangível enquanto meio digital de comunicação, tanto em sua concepção quanto no momento da interação. Procura-se realizar um panorama histórico da evolução das interfaces digitais, desde seu surgimento em computadores por meio das interfaces gráficas até a Internet das Coisas, fenômeno emergente nas mídias digitais que tangibiliza a interação do computador para objetos conectados. Levantam-se alguns métodos para análise e concepção de interfaces gráficas do ponto de vista de design e estética da interação. Transpõem-se alguns atributos destes métodos para a concepção de interfaces tangíveis, contemplando, além da usabilidade, a assimilação de aspectos táteis e manipulação, conceitos advindos do design de produtos. De modo a aprofundar esta pesquisa, foram selecionadas três produções experimentais no meio acadêmico para uma análise aprofundada de suas interfaces tangíveis aplicando o protocolo discutido: inFORM (http://tangible.media.mit.edu/project/inform/), uma interface multi-toque que aborda processos de comunicação através da conexão do humano com o objeto à distância; Daily Stack (https://vimeo.com/10458491/), que funciona como um meio pelo qual o usuário organiza tarefas abstratas em forma de blocos físicos conectados a um software; e ZeroN (http://tangible.media.mit.edu/project/zeron-levitated-interaction-element/), que explora a interação do usuário-máquina através de uma interface levitante, questionando o objeto como especulação poética e metafísica da interação. Como conclusões, as interfaces tangíveis ainda precisam resolver alguns desafios como resolução, escala e custo antes de esperarmos uma adoção completa pelo público. Porém, eles podem permitir um tipo de interação física mais rica que as Interfaces Gráficas, enquanto ajudar usuários no seu uso sem a necessidade de ter uma tela presente nas suas interações

Um dos principais desafios de pesquisa na UbiComp consiste em fornecer mecanismos para a ciência de contexto que promovam o desenvolvimento de aplicações que reajam de acordo com a dinâmica do ambiente de interesse do usuário. Para manter o conhecimento a respeito desse ambiente, a área da UbiComp pressupõe a utilização de informações produzidas e disponibilizadas em diferentes localizações, o tempo todo. Nesse sentido, os recentes avanços na área da Internet das Coisas (IoT) têm proporcionado uma crescente disponibilidade de sensores conectados em rede, os quais são potenciais produtores de informações contextuais do ambiente para aplicações ubíquas. Com essa motivação, nessa tese é apresentado o COIOT, um middleware para Internet das Coisas concebido com o objetivo de gerenciar a coleta e o processamento das informações contextuais do ambiente físico, bem como a atuação remota sobre o mesmo. O COIOT foi idealizado considerando os trabalhos previamente desenvolvidos pelo grupo de pesquisa GPPD (Grupo de Processamento Paralelo e Distribuído) da UFRGS, particularmente o middleware EXEHDA (Execution Environment for Highly Distributed Applications). Na concepção do COIOT foi adotada uma abordagem distribuída de processamento de contexto que contempla tanto as premissas da IoT quanto as demandas das aplicações da UbiComp. A arquitetura proposta também contempla o gerenciamento de eventos distribuídos através de regras e triggers para tratar as mudanças de estados dos contextos de interesse. Além disso, a arquitetura proposta gerencia outros aspectos importantes nos cenários da IoT, como o tratamento da interoperabilidade, da heterogeneidade, apoio ao controle da escalabilidade e descoberta de recursos. As principais contribuições desta tese são: (i) a concepção de uma arquitetura para IoT capaz de realizar de forma distribuída tanto a coleta e processamento das informações contextuais, como a atuação remota no meio a fim de atender as aplicações da UbiComp e, (ii) a proposição de um modelo de processamento de eventos distribuídos adequado aos cenários da IoT. Para avaliar a arquitetura do COIOT foram realizados dois estudos de caso na área da agricultura. O primeiro estudo de caso foi desenvolvido em ambiente de produção a partir de demandas de pesquisadores da área da agricultura, particularmente da análise de sementes. Já o segundo estudo de caso teve como cenário de testes ambientes da viticultura de precisão. / One of the main research challenges in UbiComp is to provide mechanisms for context-aware to promote the development of applications that react according to the dynamics of user interest environment. To keep the knowledge of this environment, the area of UbiComp presupposes the use of information produced and made available in different locations, all the time. In this sense, the recent advances in the field of Internet of Things (IoT) have provided an increasing availability of sensors and actuators networked. These sensors are potential producers of contextual information. With this motivation, this thesis is presented the CoIoT, a middleware for Internet of Things (IoT) designed in order to manage the collect and processing of contextual information of the physical environment as well as remote actuation on it. The CoIoT was designed considering the work previously developed by the research group GPPD (Parallel Processing Group and distributed) of UFRGS, particularly middleware EXEHDA (Execution Environment for Highly Distributed Applications). In designing the CoIoT it was adopted a distributed approach of context processing that includes both the principles of IoT as the demands of the applications of UbiComp. The proposed architecture also includes rules based and triggers mechanisms to deal with events that characterize the changes of states of the contexts of interest. In addition, the proposed architecture manages other important aspects of IoT scenarios such as the treatment of interoperability, heterogeneity, support the control of scalability and resource discovery. Until now, the central contributions of this thesis include: (i) the design of an architecture for IoT able to perform distributed way both the collect and processing of contextual information, such as remote actuation in the environment in order to meet UbiComp applications and, (ii) the proposition of a distributed event processing model appropriate to the IoT scenarios. In order to evaluate the CoIoT architecture, two case studies were carried out in the area of agriculture. The first case study was developed in a production environment based on the demands of agricultural researchers, particularly seed analysis. On the other hand, the second case study was based on precision testing of viticulture environments.

A Computação Ubíqua (UbiComp) foi introduzida na década de 90 como a área de pesquisa que estuda a integração da tecnologia às tarefas cotidianas, com a intenção de proporcionar aos usuários a manutenção do foco em suas atividades, reduzindo a necessidade de seu envolvimento com a gerência da infraestrutura computacional. Considerando esta perspectiva de integração das tecnologias, exigindo o mínimo de participação do usuário, um dos desafios centrais de pesquisa para contemplar essa proposta da UbiComp é a Ciência de Situação. A construção do suporte à Ciência de Situação para as aplicações ubíquas envolve a representação do contexto, a coleta, o armazenamento e o processamento dos dados contextuais, bem como a identificação e disseminação das situações, de forma autônoma. Dentre as maneiras que tem sido consideradas para materializar a UbiComp, vem se destacando a Internet das Coisas (Internet of Things - IoT). Esta abordagem utiliza a Internet como principal meio para interoperação entre dispositivos computacionais. Nesse sentido, a IoT tem como premissa unir o mundo físico ao digital, preconizando a ideia do “tudo conectado”, criando assim uma rede de objetos incorporados ao ambiente de forma ubíqua. Deste modo, esta tese tem como objetivo conceber uma arquitetura para provimento de Ciência de Situação às aplicações ubíquas, na perspectiva da infraestrutura da Internet das Coisas. A arquitetura, denominada SAUI (Situation-aware Architecture for Ubiquitous applications in the Internet of things), é concebida considerando os trabalhos previamente desenvolvidos pelo grupo de pesquisa GPPD/UFRGS, particularmente o middleware EXEHDA (Execution Environment for Highly Distributed Applications) Entende-se como contribuições centrais desta tese: (i) a definição de uma abordagem híbrida para representação e processamento do contexto, visando à identificação de situações de interesse das aplicações; e (ii) a concepção de uma arquitetura distribuída, baseada em eventos e regras, visando o suporte à Ciência de Situação das aplicações ubíquas, considerando a infraestrutura provida pela IoT. As funcionalidades da Arquitetura SAUI são avaliadas através de cenários de uso nas áreas de agropecuária e saúde, sendo caracterizados os protótipos desenvolvidos, as tecnologias empregadas e os testes realizados. Os resultados obtidos corroboram com a abordagem da Arquitetura SAUI de considerar um suporte concomitante para operação distribuída, tratamento autônomo dos dados contextuais baseado em eventos e regras, e processamento híbrido do contexto, visando à identificação de situações de interesse das aplicações. / The Ubiquitous Computing (UbiComp) was introduced in the 90s as the area of research that studies the integration of technology in the everyday tasks, with the objective to keep the focus of the users in their activities, reducing the need of their involvement in the management of the computational infrastructure. Considering this perspective of technologies integration, requiring minimal user participation, one of the central research challenges is the situation awareness. The construction of the support to situation awareness for ubiquitous applications involves the representation of context; the acquisition, storage and processing of contextual data; and the identification and dissemination of situations, in autonomous way. Among the ways that have been considered to materialize UbiComp, has been highlighting the IoT (Internet of Things). This approach uses the Internet as the main means for interoperation between computing devices. In this sense, the IoT has the premise of join the physical and digital worlds, contemplating the idea of “everything connected”, thus creating a network of objects embedded in the environment ubiquitously. Thus, this thesis aims to design an architecture for providing situation awareness to ubiquitous applications, considering the IoT infrastructure. The architecture, called SAUI (Situation-aware Architecture for Ubiquitous applications in the Internet of things), is designed considering the work previously developed by the research group GPPD/UFRGS, particularly EXEHDA middleware (Execution Environment for Highly Distributed Applications) It is considered as central contributions of this thesis: (i) the definition of a hybrid approach for modeling and processing of context, aiming at identification of situations of interest of the applications; and (ii) the design of a distributed architecture, driven by events and rules, aiming at supporting the situation awareness of ubiquitous applications, considering an IoT infrastructure. The funcionalities of SAUI architecture are evaluated through usage scenarios in the areas of agriculture and healthcare. It was characterized the developed prototypes, the technologies used, and the tests performed. The results corroborate with the approach of SAUI architecture, which considers a concomitant support for distributed operation, autonomous handling of context based on events and rules, and hybrid processing of context, aiming at identification of situations.

<p>U okviru disertacije se ispituje način integracije Interneta stvari<br />(IS) u univerzitetske kampuse. Analizirani su postojeći dostupni<br />modeli za ocenu spremnosti organizacija za IS. Prikazani su aktuelni<br />stavovi o mogućnostima primene IS-a u kampusima. Nakon toga je<br />prikazan razvijeni model za ocenu spremnosti kampusa za primenu IS-<br />a, koji sadrži i segment za ocenu spremnosti stanara studenstkog<br />kampusa za IS. Radi testiranja modela, razvijeni su upitnici i<br />softverski alat za podršku primene modela. Razvijeni model je<br />testiran u Studentskom centru Novi Sad sa zaposlenima i stanarima<br />kampusa, nakon čega su rezultati dobijeni modelom evaluirani.</p> / <p>This dissertation discusses possibilities of Internet of Things (IoT) integration<br />in university campuses. Available existing models for assessing an<br />organization readiness for IoT are analyzed. Actual viewpoints concerning<br />possibilities of IoT application in campuses are shown. Further, developed<br />model for assessing university campus readiness assessment for IoT, which<br />also include part for campus clients IoT readiness assessment, is presented.<br />With the purpose of model testing, supporting questionnaires and software<br />tool are developed. The model is tested in Student Center Novi Sad, with<br />both employees and campus habitants, and evaluation of results was done.</p>

Alors que l’informatique en brouillard amène les ressources de traitement et de stockage à la périphérie du réseau, il existe un besoin croissant de placement automatisé (c.-à-d. La sélection de l'hôte) pour déployer des applications distribuées. Un tel placement doit être conforme aux besoins en ressources des applications dans une infrastructure de brouillard hétérogène et dynamique, et traiter la complexité apportée par les applications Internet des objets (IoT) liées aux capteurs / actionneurs. Cette thèse présente un modèle, une fonction objective et des heuristiques pour résoudre le problème de la mise en place d'applications IoT distribuées dans le brouillard. En combinant les heuristiques proposées, notre approche est capable de gérer les problèmes à grande échelle et de prendre efficacement des décisions de placement adaptées à l'objectif - en optimisant les performances des applications placées. L'approche proposée est validée par une analyse de complexité et une simulation comparative avec des tailles et des applications de tailles variables. / As fog computing brings processing and storage resources to the edge of the network, there is an increasing need of automated placement (i.e., host selection) to deploy distributed applications. Such a placement must conform to applications' resource requirements in a heterogeneous fog infrastructure, and deal with the complexity brought by Internet of Things (IoT) applications tied to sensors and actuators. This paper presents four heuristics to address the problem of placing distributed IoT applications in the fog. By combining proposed heuristics, our approach is able to deal with large scale problems, and to efficiently make placement decisions fitting the objective: minimizing placed applications' average response time. The proposed approach is validated through comparative simulation of different heuristic combinations with varying sizes of infrastructures and applications.

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.

The Internet of Things (IoT) is the next phase in the evolution of the internet, where everyday objects are connected to the internet, and obtain the capacity to communicate with other devices and sense their environment. Especially the IIoT is one of the most talked about industrial business concepts since the recent years, companies try to focus on business models and operational efficiency. That is why this thesis focuses on researching the industrial Internet of Things (IIoT). There is already a lot of information about the common Internet of Things but still a gap in research in the business perspective, especially surrounding the concept of business models for the IIoT. The goal of this project is to investigate different kinds of business models, how they work and how feasible they are. The need to research possible business models for an IIoT framework, as traditional business models are relevant for this study, such as the Business Model Canvas which has been proposed by Alexander Osterwalder or the Business Model Navigator by Oliver Gassmann. But there is still a lack of literature covering the business models for the IIoT. Therefore, after researching the concept of IIoT from a business perspective, I identified some useful criteria and suitable business models. With a qualitative literature study, I was able to develop an IIoT business model framework, based on the dynamics and complexity of the IIoT concept, which incorporates business strategies and provides companies with a flexible approach. The business model framework can be used in any business which is working in the industrial context. To demonstrate how the business model framework works for the IIoT, I clarified how suitable business models can improve the current business model of the very prominent and successful company Tesla. The results show how the framework of IIoT business models can be used to increase profit and work efficiently as a company. The models can also be formed to only highlight single components of an already existing business model, as it offers great flexibility, which is highly valuable in the fast evolving and innovative IIoT phenomenon.

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.