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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
271

Cyber Physical System for Continuous Evaluation of Fall Risks to Enable Aging-In-Place

Jagtap, Vinayak 29 April 2015 (has links)
Every year, one out of three adults over the age of 65 falls, and about 30% of the falls result in moderate to severe injuries. The high rate of fall-related hospitalizations and the fact that falls are a major source of morbidity and mortality in older adults have motivated extensive interdisciplinary clinical and engineering research with a focus on fall prevention. This research is aimed at developing a medical Cyber Physical System (CPS) composed of a human supervised mobile robot and ambient intelligence sensors to provide continuous evaluation of environmental risks in the home. As a preventive measure to avoid falls, we propose use of mobile robots to detect possible fall risks inside a house. As a step-up to that, we also define a control framework for intelligent, networked mobile robots to semi-autonomously perform assistive and preventive tasks. This framework is integrated in a smart home that provides monitoring and control capabilities of environmental conditions such as objects blocking pathways or uneven surfaces. The main outcome of this work is the realization of this system at Worcester Polytechnic Institute's (WPI) @Home testbed.
272

Evaluation of decentralized email architecture and social network analysis based on email attachment sharing

Tsipenyuk, Gregory January 2018 (has links)
Present day email is provided by centralized services running in the cloud. The services transparently connect users behind middleboxes and provide backup, redundancy, and high availability at the expense of user privacy. In present day mobile environments, users can access and modify email from multiple devices with updates reconciled on the central server. Prioritizing updates is difficult and may be undesirable. Moreover, legacy email protocols do not provide optimal email synchronization and access. Recent phenomena of the Internet of Things (IoT) will see the number of interconnected devices grow to 27 billion by 2021. In the first part of my dissertation I am proposing a decentralized email architecture which takes advantage of user's a IoT devices to maintain a complete email history. This addresses the email reconciliation issue and places data under user control. I replace legacy email protocols with a synchronization protocol to achieve eventual consistency of email and optimize bandwidth and energy usage. The architecture is evaluated on a Raspberry Pi computer. There is an extensive body of research on Social Network Analysis (SNA) based on email archives. Typically, the analyzed network reflects either communication between users or a relationship between the email and the information found in the email's header and the body. This approach discards either all or some email attachments that cannot be converted to text; for instance, images. Yet attachments may use up to 90% of an email archive size. In the second part of my dissertation I suggest extracting the network from email attachments shared between users. I hypothesize that the network extracted from shared email attachments might provide more insight into the social structure of the email archive. I evaluate communication and shared email attachments networks by analyzing common centrality measures and classication and clustering algorithms. I further demonstrate how the analysis of the shared attachments network can be used to optimize the proposed decentralized email architecture.
273

PSElastic : um modelo de elasticidade multinível para Brokers Publish/Subscribe

Wendt, Ivam Guilherme 23 February 2017 (has links)
Submitted by JOSIANE SANTOS DE OLIVEIRA (josianeso) on 2017-05-24T16:53:14Z No. of bitstreams: 1 Ivam Guilherme Wendt_.pdf: 2573131 bytes, checksum: 364b08dccce8d5d89f93cdf8605772d8 (MD5) / Made available in DSpace on 2017-05-24T16:53:14Z (GMT). No. of bitstreams: 1 Ivam Guilherme Wendt_.pdf: 2573131 bytes, checksum: 364b08dccce8d5d89f93cdf8605772d8 (MD5) Previous issue date: 2017-02-23 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / A Internet das Coisas (IoT - Internet of Things) é considerada a próxima grande evolução na era da computação após a Internet. Na Internet das Coisas muitos objetos que nos rodeiam serão conectados em redes e se comunicarão entre sí sem auxílio ou intervenção humana. Implementações de grande escala têm potencial para criar um enorme tráfego agregado. Muitas vezes Brokers ou Intermediários, são utilizados para possibilitar esta comunicação machine-to-machine (M2M), utilizando o modelo de comunicação Publish/- Subscribe que possui diversas bibliotecas particulares para uso na Internet das Coisas. Alguns trabalhos desenvolvidos pela comunidade visam tratar o desempenho no ambiente de Brokers Publish/Subscribe, no entanto impõem modificações e restrições quanto aos Brokers e arquitetura utilizada. Neste cenário, visando atender a necessidade de escalabilidade citada, é proposto um modelo de elasticidade chamado PSElastic. PSElastic fornece um modelo de elasticidade multinível para Brokers Publish/Subscribe, fazendo uso da elasticidade provida pela Computação em Nuvem, sem afetar o desempenho do sistema e sem a necessidade de investimentos ou ajustes por parte dos clientes e aplicações que fazem uso deste modelo. O modelo oferece a elasticidade de forma automática, reativa e multinível, onde multinível refere-se aos níveis de Broker e de Orquestrador do modelo. Buscando avaliar o modelo PSElastic foram definidos três cenários diferentes para a execução dos testes: Cenário 1, sem elasticidade; Cenário 2, elasticidade na camada de Brokers e Cenário 3, elasticidade multinível. Diferentes limites de réplicas de máquinas virtuais foram utilizados, assim como combinações de thresholds para avaliar o Tempo de Execução, quantidade de Mensagens por Segundo tratadas e a Eficiência na utilização dos recursos computacionais. PSElastic apresentou excelentes resultados ao reduzir em até 81,2% o tempo necessário para o tratamento de uma carga de dados e aumentar o throughput do ambiente com Broker Mosquitto de 54,95 mensagens por segundo (Mps) para 235,29 Mps e de 38,02 Mps para 202,02 Mps no ambiente com Broker RabbitMQ. / The Internet of Things (IoT) is considered the next big evolution in the computing era after the Internet. In Internet of Things many objects around us will be connected in networks and will communicate among themselves without assistance or human intervention. Large scale implementations has potential to create a huge aggregate traffic. Often brokers or intermediaries, are used to enable this machine-to-machine (M2M) communication using the Publish/Subscribe communication model that has several private libraries for use in Internet of Things. Some works developed by the community aim to treat performance in Publish/Subscribe brokers environment, however impose modifications and restrictions regarding brokers and architecture used. In this scenario, aiming to fulfill the need for cited scalability, we propose a elasticity model called PSElastic. The model provides an model with multilevel elasticity for Publish/Subscribe Brokers, making use of the elasticity promoted by cloud computing, not affecting system performance and without the need for investments or adjustments by customers and applications that make use of this model. PSElastic offers elasticity in the following manners: automatic, reactive and uses the multilevel elasticity, where multilevel refers to Broker level and Orchestrator model. In order to evaluate the model PSElastic, three different scenarios for execution of tests were defined: Scenario 1, without elasticity; Scenario 2, elasticity in the layer of Broker and Scenario 3, multilevel elasticity. Different limits of replica of virtual machines were used, as well as thresholds to evaluate Execution Time, number of Messages per Second handled and Efficiency in the use of computational resources. PSElastic showed excellent results by reducing the time needed to handle a data load by up to 81.2% and increase the throughput of the environment with Mosquitto Broker from 54.95 messages per second (Mps) to 235.29 Mps and from 38.02 Mps to 202.02 Mps in the environment with RabbitMQ Broker.
274

Energy efficient channel access mechanism for IEEE 802.11ah based networks

Wang, Yanru January 2018 (has links)
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.
275

Antenna design with characteristic mode analysis for Internet of Things applications

Zhang, Qianyun January 2018 (has links)
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.
276

Objetos conectados: um olhar sobre a usabilidade e design das interfaces tangíveis

Portella, Grazielle Bruscato 01 September 2016 (has links)
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
277

Um middleware para internet das coisas com suporte ao processamento distribuído do contexto

Souza, Rodrigo Santos de January 2017 (has links)
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.
278

Uma arquitetura para provimento de ciência de situação direcionada às aplicações ubíquas na infraestrutura da internet das coisas / An architecture for situation awareness targeted to ubiquitous applications in the infrastructure of the internet of things

Lopes, Joao Ladislau Barbara January 2016 (has links)
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.
279

Integracija interneta stvari u univerzitetskim kampusima / Integration of Internet of Things in University Campuses

Arsenijević Dejan 05 April 2019 (has links)
<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>
280

Combining Heuristics for Optimizing and Scaling the Placement of IoT Applications in the Fog / Combinaison d'heuristiques pour optimiser et dimensionner le placement d'applications IoT dans le Fog

Xia, Ye 17 December 2018 (has links)
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.

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