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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.
11

A Service-Based Decentralized Architecture for ECU Fault Tolerant Control

Zhou, Xia January 2012 (has links)
The purpose of this master thesis is to contribute a service-based decentralized architecture for Electronic Control Unit (ECU) with fault tolerant control. As ECU systems are becoming large-scaled, centralized-architecture fault tolerant control is facing challenges in performance, complexity and engineering, for its dependencies, non-modular, non-scalable and so on. In Scania’s ECUs, the architecture is applied by a centralized diagnose system. In this thesis, an alternative solution – service-based decentralized architecture is presented. In the architecture, both diagnostic and reconfiguration are completely decentralized in modules of ECU system. Modules can be seen as a software component with self fault tolerant control abilities, which provides different quality of service to system. A purely service view of ECU system can be built as the foundation both for fault tolerant control architecture and for modeling control system. The thesis project is, firstly to implement a general decentralized diagnostic platform which can be called by modules of Scania Exhaust Emission Control system (EEC3) system. A centralized communication node is constructed for off-board diagnosis by PC-tools. Lastly, service based architecture is built in EEC3 PUMC module as service provider.
12

Breaking Free From Financial Inertia : The Barriers Causing and Enablers Mitigating Financial Inertia in Circular Business Model Transitions

Arbenius, Paula, Norling, Elias January 2023 (has links)
Background: Regulations and Governments prompt companies to reassess their practices and align with sustainability standards. It emphasizes a transition towards circular business practices, which requires large amounts of capital to commit to the adoption of circularity fully. The transportation sector is a prime example of an industry undergoing a significant circular transformation due to its environmental impact. Circular servitization has complemented the circular transformation by offering products as services instead of selling them outright. This has had severe financial statement implications since the operations differ from linear practices and requires large investments. Financial institutions still assume techniques, modulation, and evaluation processes adapted for linear purposes, which creates obstacles to capturing the value circular business models generate. Subsequently, financial institutions are hesitant to fund circular business models due to the perception of increased risk. Hence, financial inertia occurs and hinders the development of circular businesses.  Purpose: This research adopts the perspective of financial institutions and examines the barriers and enablers that impact companies' transitions to circular business models, leading to or mitigating financial inertia.  Method: The study is qualitative and adopted an abductive approach to contrast theory and findings with the interpretive research paradigm. The primary data was collected from eleven different respondents from a Swedish financial institution. Sampling was done non-randomly with a purposive sample and a convenience input to gather data from respondents who were part of the financial institution and knowledgeable in the circular transition.  Findings: The aim of the study was to answer two research questions regarding barriers causing, and enablers mitigating financial inertia. The findings provided three soft and six hard barriers relating to financial techniques, modeling, and evaluation methods, along with internal competence about circularity, stakeholder involvement, and regulations. Additionally, the study found three soft and six hard enablers which could be interpreted as underlying drivers for mitigating financial inertia.
13

Voices of entrepreneurship and small business : immigrant enterprises in Kista, Stockholm

Dalhammar, Tobias January 2004 (has links)
<p>Immigrant and ethnic entrepreneurship is a subject that has received increased attention in recent years. Many immigrants or people with ethnic backgrounds different from the majority population run their own businesses, in Sweden as well as in most countries and contexts in the world. However, ambitious research shows that there are great differences in business activity, behaviour and performance between different ethnic groups. Besides, it is easy to argue that differences also occur at the individual level. Thus, a person is not predetermined just because he/she belongs to a definable ethnic group. Another important question is the fact that the industrial setting and the context of the individual firm also affect the activity of the firm and the entrepreneur. E.g. in high tech environments, innovative competences may be of greater importance compared to business activity in the restaurant or retail sectors, where one could imitate already successful concepts.</p><p>In this dissertation immigrant as well as ethnic enterprises (where ethnic entrepreneurs are those who have clear ethnic involvement in terms of accessing and utilising different forms of ethnic resources) in different industries are studied. The work hypothesis, or rather assumption, is that the industry of the individual business plays an important role for the access to and utilisation of different forms of resources (organisational, financial, cultural, social, human, ethnic). Further, the industry of a business is also assumed to have an effect on the access to and utilisation of ethnic resources and the own ethnicity as a resource. The purpose of this study is to through a number of case studies explore the influence of ethnic background for immigrant businesses in different industries. The focus is on how ethnic involvement, thus ethnic resources, and identity as immigrant and/or ethnic business influence firms in their resource bases and resource acquisition efforts. That is, if the objective ethnic background is important for the firms in their resource acquisition efforts.</p><p>Since I want to study individual firms in an open and complex way I use a qualitative methodology with a multi-method approach, including ethnographic elements, direct observations, participant observations and interviews. This way, the possibility exists to grasp individual personal and firm characteristics that pay attention to the complexity and variation of immigrant and ethnic entrepreneurship, an issue that tends to be forgotten in broad descriptions of the subject. The Kista district hereby provides an interesting example with its high technology context, mixed with a considerable amount of immigrants living in the area.</p><p>The exploratory study of seven businesses shows that there are important differences between firms in different industries. However, apart from type of firm and kind of venture opportunity exploited, the action mode of the individual(s) involved and the degree of confirmation and legitimacy the businesses have experienced influence and affect the importance of ethnic background for these firms.</p>
14

Modeling, evaluation and provisioning of elastic service-based business processes in the cloud / Modélisation, évaluation et mise en oeuvre de l'élasticité des applications à base de services dans le cloud

Amziani, Mourad 12 June 2015 (has links)
Le Cloud Computing est de plus en plus utilisé pour le déploiement et l'exécution des applications métiers et plus particulièrement des applications à base de services (AbSs). L'élasticité à différents niveaux est l'une des propriétés fournies par le Cloud. Son principe est de garantir la fourniture des ressources nécessaires et suffisantes pour la continuité de l'exécution optimale des services Cloud. La fourniture des ressources doit considérer la variation de la demande pour éviter la sous-utilisation et la surutilisation de ces dernières. Il est évident que la fourniture d'infrastructures et/ou de plateformes élastiques n'est pas suffisante pour assurer l'élasticité des applications métiers déployées. En effet, il est aussi nécessaire de considérer l'élasticité au niveau des applications. Ceci permet l'adaptation dynamique des applications déployées selon la variation des demandes. Par conséquent, les applications métiers doivent être fournies avec des mécanismes d'élasticité permettant leur adaptation tout en assurant les propriétés fonctionnelles et non-fonctionnelles désirées. Dans nos travaux, nous nous sommes intéressés à la fourniture d'une approche holistique pour la modélisation, l'évaluation et la mise en oeuvre des mécanismes d'élasticité des AbSs dans le Cloud. En premier lieu, nous avons proposé un modèle formel pour l'élasticité des AbSs. Pour cela, nous avons modélisé les AbSs en utilisant les réseaux de Petri et défini deux opérations d'élasticité (la duplication et la consolidation). En outre, nous avons proposé de coupler ces deux opérations avec un contrôleur d'élasticité. Pour assurer l'élasticité des AbSs, le contrôleur analyse l'exécution des AbSs et prend des décisions sur les opérations d'élasticité (duplication/consolidation). Après la définition de notre modèle pour l'élasticité des AbSs, nous nous sommes intéressés à l'évaluation de l'élasticité avant de l'implémenter dans des environnements Cloud réels. Pour cela, nous avons proposé d'utiliser notre contrôleur d'élasticité comme un Framework pour la validation et l'évaluation de l'élasticité en utilisant des techniques de vérification et de simulation. Enfin, nous avons mis en oeuvre l'élasticité des AbSs dans des environnements Cloud réels. Pour cela, nous avons proposé deux approches. La première approche encapsule les AbSs non-élastiques dans des micro-conteneurs, étendus avec nos mécanismes d'élasticité, avant de les déployer sur des infrastructures Cloud. La seconde approche intègre notre contrôleur d'élasticité dans une infrastructure autonomique afin de permettre l'ajout dynamique des fonctionnalités d'élasticité aux AbSs déployées sur des plateformes Cloud / Cloud computing is being increasingly used for deploying and executing business processes and particularly Service-based Business Processes (SBPs). Among other properties, Cloud environments provide elasticity at different scopes. The principle of elasticity is to ensure the provisioning of necessary and sufficient resources such that a Cloud service continues running smoothly even when the number or quantity of its utilization scales up or down, thereby avoiding under-utilization and over-utilization of resources. It is obvious that provisioning of elastic infrastructures and/or platforms is not sufficient to provide elasticity of deployed business processes. In fact, it is also necessary to consider the elasticity at the application scope. This allows the adaptation of deployed applications during their execution according to demands variation. Therefore, business processes should be provided with elasticity mechanisms allowing their adaptation to the workload changes while ensuring the desired functional and non-functional properties. In our work, we were interested in providing a holistic approach for modeling, evaluating and provisioning of elastic SBPs in the Cloud. We started by proposing a formal model for SBPs elasticity. To do this, we modeled SBPs using Petri nets and defined two elasticity operations (duplication / consolidation). In addition, we proposed to intertwine these elasticity operations with an elasticity controller that monitors SBPs execution, analyzes monitoring information and executes the appropriate elasticity operation (duplication/consolidation) in order to enforce the elasticity of SBPs. After facing the challenge of defining a model and mechanisms for SBPs elasticity, we were interested in the evaluation of elasticity before implementing it in real environments. To this end, we proposed to use our elasticity controller as a framework for the validation and evaluation of elasticity using verification and simulation techniques. Finally, we were interested in the provisioning of elasticity mechanisms for SBPs in real Cloud environments. For this aim, we proposed two approaches. The first approach packages non-elastic SBPs in micro-containers, extended with our elasticity mechanisms, before deploying them in Cloud infrastructures. The second approach integrates our elasticity controller in an autonomic infrastructure to dynamically add elasticity facilities to SBPs deployed on Cloud platforms
15

A Co-Design Modeling Methodology for Simulation of Service Oriented Computing Systems

January 2011 (has links)
abstract: The adoption of the Service Oriented Architecture (SOA) as the foundation for developing a new generation of software systems - known as Service Based Software Systems (SBS), poses new challenges in system design. While simulation as a methodology serves a principal role in design, there is a growing recognition that simulation of SBS requires modeling capabilities beyond those that are developed for the traditional distributed software systems. In particular, while different component-based modeling approaches may lend themselves to simulating the logical process flows in Service Oriented Computing (SOC) systems, they are inadequate in terms of supporting SOA-compliant modeling. Furthermore, composite services must satisfy multiple QoS attributes under constrained service reconfigurations and hardware resources. A key desired capability, therefore, is to model and simulate not only the services consistent with SOA concepts and principles, but also the hardware and network components on which services must execute on. In this dissertation, SOC-DEVS - a novel co-design modeling methodology that enables simulation of software and hardware aspects of SBS for early architectural design evaluation is developed. A set of abstractions representing important service characteristics and service relationships are modeled. The proposed software/hardware co-design simulation capability is introduced into the DEVS-Suite simulator. Exemplar simulation models of a communication intensive Voice Communication System and a computation intensive Encryption System are developed and then validated using data from an existing real system. The applicability of the SOC-DEVS methodology is demonstrated in a simulation testbed aimed at facilitating the design & development of SBS. Furthermore, the simulation testbed is extended by integrating an existing prototype monitoring and adaptation system with the simulator to support basic experimentation towards design & development of Adaptive SBS. / Dissertation/Thesis / Ph.D. Computer Science 2011
16

Voices of entrepreneurship and small business : immigrant enterprises in Kista, Stockholm

Dalhammar, Tobias January 2004 (has links)
Immigrant and ethnic entrepreneurship is a subject that has received increased attention in recent years. Many immigrants or people with ethnic backgrounds different from the majority population run their own businesses, in Sweden as well as in most countries and contexts in the world. However, ambitious research shows that there are great differences in business activity, behaviour and performance between different ethnic groups. Besides, it is easy to argue that differences also occur at the individual level. Thus, a person is not predetermined just because he/she belongs to a definable ethnic group. Another important question is the fact that the industrial setting and the context of the individual firm also affect the activity of the firm and the entrepreneur. E.g. in high tech environments, innovative competences may be of greater importance compared to business activity in the restaurant or retail sectors, where one could imitate already successful concepts. In this dissertation immigrant as well as ethnic enterprises (where ethnic entrepreneurs are those who have clear ethnic involvement in terms of accessing and utilising different forms of ethnic resources) in different industries are studied. The work hypothesis, or rather assumption, is that the industry of the individual business plays an important role for the access to and utilisation of different forms of resources (organisational, financial, cultural, social, human, ethnic). Further, the industry of a business is also assumed to have an effect on the access to and utilisation of ethnic resources and the own ethnicity as a resource. The purpose of this study is to through a number of case studies explore the influence of ethnic background for immigrant businesses in different industries. The focus is on how ethnic involvement, thus ethnic resources, and identity as immigrant and/or ethnic business influence firms in their resource bases and resource acquisition efforts. That is, if the objective ethnic background is important for the firms in their resource acquisition efforts. Since I want to study individual firms in an open and complex way I use a qualitative methodology with a multi-method approach, including ethnographic elements, direct observations, participant observations and interviews. This way, the possibility exists to grasp individual personal and firm characteristics that pay attention to the complexity and variation of immigrant and ethnic entrepreneurship, an issue that tends to be forgotten in broad descriptions of the subject. The Kista district hereby provides an interesting example with its high technology context, mixed with a considerable amount of immigrants living in the area. The exploratory study of seven businesses shows that there are important differences between firms in different industries. However, apart from type of firm and kind of venture opportunity exploited, the action mode of the individual(s) involved and the degree of confirmation and legitimacy the businesses have experienced influence and affect the importance of ethnic background for these firms. / <p>QC 20161026</p>
17

Användarinvolvering i tjänst- respektive produktbaserade företag : En jämförande rapport mellan hur tjänst- och produktföretag involverar användare i sina produktutvecklingsprocesser inom elfordonsbranschen / User involvement in service- and productbased companies

Friberg, Fredrika, Lindholm, Lovisa, Tagesson, Linus January 2023 (has links)
Att involvera användare i produktutvecklingsprocesser är centralt för att förstå kundens behov samt utveckla konkurrenskraftiga produkter och tjänster. Detta kan kopplas till samtliga företag som arbetar med produktutveckling, där tjänst- respektive produktbaserade företag båda präglas av kundens behov vid skapandet av innovativa lösningar. Syftet med detta arbete är att undersöka hur involveringen av användare skiljer sig mellan företag som är tjänst- respektive produktbaserade. Rapporten syftar även till att undersöka hur fas för involvering, involveringsmetod och grad av användarinvolvering påverkar produktutvecklingsprocessen. Denna rapport baseras på en förberedande litteraturstudie som senare används för att skapa en intervjuguide. Sex intervjuer genomfördes med fyra relevanta företag som transkriberades för att finna nyckelord samt teman. Intervjuguidens fyra teman är följande: insamling av användarinformation och feedback, hantering och applicering av information och användardata i produktutvecklingsprocessen, grad av användarinvolvering samt fördelar och nackdelar med användarinvolvering. Litteraturstudien kopplas till resultatet i analys och diskussion och slutligen ges en slutsats som besvarar syftet. Rapportens slutsats belyser att det finns en märkbar skillnad gällande användarinvolvering inom tjänst- och produktbaserade företag. De tjänstebaserade företagen involverar kunden från en tidigare fas och mer kontinuerligt under produktutvecklingsprocessen. De involverar även kunden till en djupare grad. Gällande de produktbaserade företagen integreras användaren även här, men inte i samma utsträckning. Dessa företag anser att kunden inte har den tekniska kunskap som krävs för att tillföra nyttig och relevant information. En djupare grad av användarinvolvering som sker tidigt och kontinuerligt med omfattande insamlingsmetoder ger positiva effekter på produktutvecklingen om rätt användare involveras i rätt tillfälle och grad. Företag får en bättre bild av kundens behov och kan utveckla designlösningar kontinuerligt. / Involving users in product development processes is vital for understanding customer needs and developing competitive products and services. This applies to all companies working with product development, where both service-based and product-based companies are influenced by the needs to create innovative solutions. The purpose of this study is to analyse how user involvement differs between service-based and product-based companies. The report also aims to analyse how the phase of involvement, involvement method, and degree of user involvement affect the product development process. This report is based on a preparatory literature study, which was used to create an interview guide. Six interviews were conducted and transcribed, to identify keywords and themes that led to a result. The four identified themes are: collection of user information and feedback, management and application of information and data in product development processes, degree of user involvement and advantages and disadvantages of user involvement. The literature study is linked to the result in the analysis and discussion, and finally, a conclusionis formed that answers the purpose. The conclusion of the report highlights a noticeable difference in user involvement between service-based and product-based companies. Service-based companies involve the customer from an earlier phase and more continuously throughout the product development process. They also involve the customer to a deeper degree. Regarding product-based companies, the user is also involved, but not to the same extent. A deeper degree of user involvement that takes place early and continuously with extensive collection methods has positive effects on product development if the right users are involved at the right time and to the right degree. Companies get a better understanding of customer needs and can continuously developdesign solutions.
18

Uma abordagem para gerenciamento de Linhas de Produtos de Software baseada em serviços / A service-based approach for managing Software Product Lines

Pacini, Karen Dias Rabelo 05 April 2016 (has links)
Linhas de Produtos de Software (LPS) abstraem a semelhança entre produtos e envolvem o conceito de reúso de software para desenvolver software em larga escala com mais rapidez e qualidade. O reúso dos artefatos em uma LPS é planejado e executado desde sua concepção, sendo assim possível armazenar esses artefatos em um repositório (núcleo de ativos reusáveis) para utilização posterior. Porém, ao se construir um repositório para uma certa LPS, este atende apenas às especificações desta arquitetura e não promove o reúso desses ativos em outras LPS, causando uma certa perda no potencial de reusabilidade dos ativos produzidos e armazenados. Além disso, a definição e os dados da execução do processo de desenvolvimento dessas LPS também não são armazenados prevendo o reúso, o que gera retrabalho para definir e instanciar um processo de software sempre que uma nova LPS é criada. Neste contexto, este trabalho tem por objetivo apresentar uma abordagem baseada em um conjunto de serviços para promover o amplo reúso de ativos produzidos e de elementos de processo utilizados, além de facilitar a criação e o desenvolvimento de linha de produtos de software, permitindo o gerenciamento do núcleo de ativos reusáveis. Por possuir uma interface baseada em serviços, esta abordagem poderá ser incorporada também a outros ambientes. Para validar a abordagem, verificar vantagens e sugerir melhorias, foi conduzida uma prova de conceito com sua aplicação. Os resultados dessa prova comprovaram a viabilidade da abordagem em cumprir os objetivos propostos. / Software Product Lines (SPL) extract the similarity among products and use the software reuse concept to produce large-scale software with increased quality and reduction in the development time. Reuse in SPL is planned and executed since the beginning for each artifact resulting from the development process, and then these artifacts are stored in a repository (reusable core assets) for later use. However, when a repository is built for a specific SPL, it supports only the specifications for that architecture and do not promote the reuse of these assets among distinct SPL, which inhibits their reuse potential. In addition, the definition and execution data of the development process applied are not stored properly for reuse, which causes a re-work to define and instantiate a software process when creating a new SPL. In this context, this work aims at present a service-based approach to promote the wide reuse of the produced assets and process elements, also to facilitate the creation and the management of SPL and to allow the management of the reusable core assets. Once this approach has a service-based interface, it can be embedded into other environments. In order to validate this approach, point out advantages and suggest improvements, a concept proof was performed applying it. The results of this proof ensured the approach viability to fulfill the proposed goals.
19

Detecção dinâmica de antipadrões em sistemas baseados em serviços utilizando um sistema multiagente

Régis, Hugo Nathan Barbosa 31 August 2017 (has links)
Submitted by Lara Oliveira (lara@ufersa.edu.br) on 2018-03-20T21:54:36Z No. of bitstreams: 1 HugoNBR_DISSERT.pdf: 2536238 bytes, checksum: 0dfec391fbd30092d6d905cfe4301c34 (MD5) / Approved for entry into archive by Vanessa Christiane (referencia@ufersa.edu.br) on 2018-06-18T17:00:26Z (GMT) No. of bitstreams: 1 HugoNBR_DISSERT.pdf: 2536238 bytes, checksum: 0dfec391fbd30092d6d905cfe4301c34 (MD5) / Approved for entry into archive by Vanessa Christiane (referencia@ufersa.edu.br) on 2018-06-18T17:00:34Z (GMT) No. of bitstreams: 1 HugoNBR_DISSERT.pdf: 2536238 bytes, checksum: 0dfec391fbd30092d6d905cfe4301c34 (MD5) / Made available in DSpace on 2018-06-18T17:00:49Z (GMT). No. of bitstreams: 1 HugoNBR_DISSERT.pdf: 2536238 bytes, checksum: 0dfec391fbd30092d6d905cfe4301c34 (MD5) Previous issue date: 2017-08-31 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / During development of Service-Based Systems (SBS), bad solutions, design or implementation errors can lead to antipatterns that, as opposed to patterns, are bad specifications for recurring problems. Antipatterns result in deviations of functionality during the execution of the system, not adequately satisfying its requirements, which can degrade the Quality of Service (QoS) of the SBS. Its detection and correction are of extreme importance, the emergence of antipatterns may hinder future maintenance and evolution of SBS. As detection method, this work proposes the use of a Multiagent System (MAS), executing search at runtime and notifying the system administrator of QoS drops on the SBS caused by antipatterns. The detection of these antipatterns allows the agents to act in correction the project using the solution recommended by the MAS for the detected problem. The results show that, in the worst cases, the emergence of antipatterns reached extrapolate up to twice the response time of services in a Web Service. The MAS was able to detect, in execution time, the 3 antipatterns studied at work. When adopted, the solutions proposed by the MAS also normalized the response time / Durante o desenvolvimento de Sistemas Baseados em Serviços (SBS), soluções ruins, erros de projeto ou implementação podem conduzir ao surgimento de antipadrões, que em oposição aos padrões, são especificações ruins para problemas recorrentes. Antipadrões acarretam em desvios de funcionalidade durante a execução do sistema, não satisfazendo adequadamente aos seus requisitos, o que pode degradar a Qualidade de Serviço (QoS) de um SBS. Sua detecção e correção são de extrema importância pois o surgimento de antipadrões pode dificultar a manutenção e a futura evolução do SBS. Como método de detecção, este trabalho propõe o uso de um Sistema Multiagente (SMA), realizando buscas em tempo de execução e notificando ao administrador do sistema sobre quedas de QoS no SBS causadas por antipadrões. A detecção desses antipadrões permite a atuação dos agentes na correção do projeto, usando a solução recomendada pelo SMA para o problema detectado. Os resultados mostraram que, nos piores casos, o surgimento de antipadrões chegou a extrapolar em até o dobro de tempo de resposta dos serviços em um Web Service. O SMA foi capaz de detectar, em tempo de execução, os 3 antipadrões estudados no trabalho. Quando adotadas, as soluções propostas pelo SMA também normalizaram o tempo de resposta / 2018-03-20
20

Um sistema de reputação para interação baseada em serviços

Molina, Fernando Henrique Ferrarezi 03 March 2016 (has links)
Submitted by Daniele Amaral (daniee_ni@hotmail.com) on 2016-10-03T19:31:10Z No. of bitstreams: 1 DissFHFM.pdf: 5748298 bytes, checksum: d57e4d617ea74342f31ff21aef4eb98b (MD5) / Approved for entry into archive by Marina Freitas (marinapf@ufscar.br) on 2016-10-10T17:27:52Z (GMT) No. of bitstreams: 1 DissFHFM.pdf: 5748298 bytes, checksum: d57e4d617ea74342f31ff21aef4eb98b (MD5) / Approved for entry into archive by Marina Freitas (marinapf@ufscar.br) on 2016-10-10T17:27:59Z (GMT) No. of bitstreams: 1 DissFHFM.pdf: 5748298 bytes, checksum: d57e4d617ea74342f31ff21aef4eb98b (MD5) / Made available in DSpace on 2016-10-10T17:28:10Z (GMT). No. of bitstreams: 1 DissFHFM.pdf: 5748298 bytes, checksum: d57e4d617ea74342f31ff21aef4eb98b (MD5) Previous issue date: 2016-03-03 / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Service-based communication is becoming increasingly relevant, as seen in the Internet of Things scenarios. Choosing an adequate service however can be a difficult task, as this form of communication may involve sensible resources and data. A trustworthy, safe, and privacy preserving mechanism is desirable for service selection. Reputation systems can help in this selection. This thesis presents a reputation system for service selection based on the security and privacy mechanisms of crypto-coins. In order to evaluate the performance of the proposed mechanism in the identification of low quality service providers we also investigated the use of different formulations used to determine a reputation based on peer voting. Results from simulation show the proposed system architecture is viable and supports large adoption via a scalable infrastructure. The performance analysis of different formulations for the calculus of reputations also shows that the recent behavior of an entity is the most impacting factor in establishing its reputation. / A comunicação por meio de serviços tem se tornado cada vez mais relevante, como em cenários da Internet das Coisas. A escolha entre serviços, contudo, pode ser uma tarefa difícil, já que essa forma de comunicação pode envolver recursos e dados sensíveis. Assim, é preciso um sistema de seleção de serviços que seja confiável, seguro e privado, garantindo que as expectativas dos utilizadores dos serviços sejam alcançadas. Sistemas de reputação podem ajudar nessa seleção. Assim, este trabalho apresenta um sistema de reputação distribuído para avaliação de interações baseadas em serviços utilizando conceitos da arquitetura de sistemas das cripto moedas. Para avaliar o desempenho na detecção de serviços de baixa qualidade utilizando o mecanismo proposto, apresenta-se também um estudo do comportamento de diferentes formulações para o cálculo de reputações. Resultados obtidos via simulação mostram que a arquitetura do sistema de reputação proposto é viável e permite uma ampla adoção com uma infraestrutura escalável. A análise do comportamento das formulações também permite concluir que o histórico recente do comportamento dos elementos avaliados é o fator que mais influencia na qualificação dos dispositivos.

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