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[pt] Blockchain e Tangle são estruturas de dados usadas para criar um registro público imutável de dados segurados por uma rede de participantes peer-to-peer que mantém um conjunto de registros de dados em constante crescimento conhecidos como ledgers. As tecnologias Blockchain e Tangle são uma solução descentralizada que garante a troca de grandes quantidades de mensagens confiáveis, entre bilhões de dispositivos de IoT conectados, os quais são muito valiosos, desde que sejam válidos e completos. Esse mecanismo de mensagens peer-to-peer altamente criptografado e seguro é adotado neste projeto para gerenciar o processamento de transações de IoT e a coordenação entre os dispositivos que interagem com o processo. Para manter as transações privadas e seguras, os algoritmos de consenso distribuídos são responsáveis por validar e escolher as transações e registrá-las no ledger global. Os resultados mostraram que a velocidade dos algoritmos de consenso pode afetar a criação em tempo real de histórias confiáveis que rastreiam os eventos das redes IoT. Após incorporar o Processamento de Eventos Complexos, que permite selecionar apenas os eventos de alto nível, é possível obter uma melhoria em muitas situações. O resultado é um sistema Middleware que fornece framework para a construção de aplicativos de larga escala onde podem usar Processamento de Eventos Complexos e diferentes ledgers descentralizados, como o blockchain da Ethereum ou IOTA Tangle, para armazenamento seguro de dados. / [en] Blockchain and Tangle are data structures and protocols used to create an immutable public record of data ensured by a network of peer-to-peer participants that maintain a monotonic constantly growing set of data records known as ledgers. Both technologies provide a decentralized solution that guarantees the exchange, among billions of IoT devices, of large amounts of trusted messages, which are very valuable as long as they are valid and complete. This highly encrypted and secure peer-to-peer messaging mechanism is adopted in this project to manage the processing of IoT transactions. To maintain transactions private, and secured consensus algorithms are responsible for validating and choosing transactions and recording them in the global ledger. The results showed that the speed of the consensus algorithms can affect the creation in real-time of reliable stories that track the events of the IoT networks. After incorporating Complex Event Processing that allows selecting only those high-level events, it is possible to obtain an improvement in many situations. The result is a Middleware system that provides a framework for the construction of large-scale computer applications that use Complex Events Processing and different decentralized ledgers such as the blockchain of Ethereum or IOTA Tangle, for secure data storage.

This article analyses the impact of the IOTA distributed ledger technology (DLT) on smart cities. The world population is rapidly increasing while at the same time trends such as urbanization shape future demographics. Thus, fast-growing cities face the challenge of increasing demands in resources such as energy, water, transportation, while at the same time aiming to increase life quality by reducing burdens such as pollution and waste. The concept of a “Smart City” emerged with the ambition to solve a city’s issues by creating social and economic advantages while providing efficient resource allocation processes. Nevertheless, current information communication technologies tend to underperform a smartcities systems requirement since the quantity of connected devices increases which slows down the transition of a city becoming smart. The distributed ledger technology IOTA promises to enable automated, feeless transactions and processes with a high level of integrity, which may impact the development of smart cities. In this research the IOTA technology is introduced and investigated. The advantages of IOTA compared to conventional information communication technologies and the blockchain technology are highlighted. Thereafter, the current state of IOTA in smart cities is reviewed by analysing current research and use cases. To investigate the concept of a smart city the smart city initiative framework, including its subcategories is introduced. Additionally, different experts working on IOTA integrations related to smart city initiatives were interviewed giving insights into their field ofexpertise. Finally, an analysis and discussion of the IOTA technology use cases are put into relation with the multi-level perspective framework (Geels, 2006) highlighting the positive impact of IOTA on the development of smart cities. / I den här artikeln analyseras effekterna av IOTA:s teknik för distribuerade huvudböcker (DLT) på smarta städer. Världens befolkning ökar snabbt samtidigt som trender som urbanisering formar framtidens demografi. Snabbt växande städer står därför inför utmaningen att öka kraven på resurser som energi, vatten och transporter, samtidigt som de strävar efter att öka livskvaliteten genom att minska belastningar som föroreningar och avfall. Begreppet smart stad uppstod med ambitionen att lösa stadensproblem genom att skapa sociala och ekonomiska fördelar och samtidigt tillhandahålla effektiva processer för resursfördelning. Den nuvarande informations- och kommunikationstekniken tenderar dock att inte uppfylla kraven på system för smarta städer, eftersom mängden anslutna enheter ökar, vilket gör att övergången till en smart stad blir långsammare. Den distribuerade huvudbokstekniken IOTA lovar att möjliggöra automatiserade, felfria transaktioner och processer med en hög grad av integritet, vilket kan påverka utvecklingen av smarta städer. I den här forskningen introduceras och undersöks IOTA-tekniken. Fördelarna med IOTA jämfört med konventionell informationskommunikationsteknik och blockkedjetekniken lyfts fram. Därefter granskas det nuvarande läget för IOTA i smarta städer genom att analysera aktuell forskning och användningsfall. För att undersöka begreppet smart stad introduceras ramverket för initiativet för smarta städer, inklusive dess underkategorier. Dessutom intervjuades olika experter som arbetar med IOTA-integrationer isamband med initiativ för smarta städer för att ge en inblick i deras expertisområde. Slutligen analyseras och diskuteras IOTA-teknikens användningsområden i förhållande till ramverket för flernivåperspektivet (Geels, 2006), där IOTA:s positiva inverkan på utvecklingen av smarta städer lyfts fram.

Submitted by Sara Ribeiro (sara.ribeiro@ucb.br) on 2017-06-01T20:55:55Z No. of bitstreams: 1 ArthurHenriquePereiraTeseParcial2015.pdf: 625611 bytes, checksum: 72c916368b06d32685c569816ae62499 (MD5) / Approved for entry into archive by Sara Ribeiro (sara.ribeiro@ucb.br) on 2017-06-01T20:57:03Z (GMT) No. of bitstreams: 1 ArthurHenriquePereiraTeseParcial2015.pdf: 625611 bytes, checksum: 72c916368b06d32685c569816ae62499 (MD5) / Made available in DSpace on 2017-06-01T20:57:03Z (GMT). No. of bitstreams: 1 ArthurHenriquePereiraTeseParcial2015.pdf: 625611 bytes, checksum: 72c916368b06d32685c569816ae62499 (MD5) Previous issue date: 2015-11-06 / The present thesis used Heath Ledger???s acting career in the production and interpretation of the Joker character in the movie Batman ??? The dark knight, to investigate the phenomenon denominated by the US media as "Joker effect". It is suspected that immersion in character generated an imaginary experience in the actor, which caused a disturbing and fatal psychological reality effect. For this research, we studied the case through the theoretical and bibliographical research, seeking imaginary theory to show how this intersects with the construction of the actor's role; and subsequently referred to the Stanislavski theory, which was approximated to Jung???s psychoanalysis, and sometimes Deleuze, to show the relationship between the creation and the creator, as well as the psychological processes that are caused and affected. Based on this theoretical material, we were able to analyze the interviews on Heath regarding his professional and personal practice, connecting them with the imaginary development of the Joker and its effect on the actor. / En esta tesis se utiliz?? la carrera del actor Heath Ledger en la producci??n y interpretaci??n del Joker personaje de la pel??cula de Batman - The Dark Knight, para investigar el fen??meno llamado por los medios de comunicaci??n estadunidense del "efecto Joker". Se sospecha que la inmersi??n en car??cter genera una experiencia imaginaria en el actor hab??a causado un efecto de realidad psicol??gica inquietante y fatal. Para realizar esta investigaci??n, se estudi?? el caso a trav??s de la investigaci??n te??rica y bibliogr??fica, la b??squeda de la teor??a imaginario para mostrar c??mo este se cruza con la construcci??n del rol del actor y luego usando la teor??a de Stanislavski, que se aproxima al psicoan??lisis Jung, ayudando a veces Deleuze, para mostrar la relaci??n entre la creaci??n y el creador, y los procesos psicol??gicos que se producen y afectados. Sobre la base de este material te??rico, podr??amos analizar las entrevistas sobre Heath sobre su pr??ctica profesional y personal, conect??ndolos con el desarrollo imaginario del Joker y su efecto causado el actor. / A presente tese utilizou a trajet??ria do ator Heath Ledger na produ????o e interpreta????o da personagem Curinga no filme Batman ??? cavaleiro das trevas, para investigar o fen??meno denominado pela m??dia norte-americana de ???efeito Curinga???. Suspeita-se que a imers??o na personagem gerou uma experi??ncia imagin??ria no ator que provocou um efeito de realidade psicol??gica perturbadora e fatal. Para tal investiga????o, estudou-se o caso por meio da pesquisa te??rico-bibliogr??fica, buscando a teoria do imagin??rio para mostrar como este se intersecta com a constru????o do papel do ator e, em seguida, recorrendo ?? teoria de Stanislavski que foi aproximada ?? psican??lise de Jung, auxiliando-se, ??s vezes, de Deleuze, para mostrar a rela????o entre a cria????o e o criador, e os processos psicol??gicos que s??o provocados e afetados. Tendo como base esse material te??rico, foi poss??vel analisar as entrevistas sobre Heath a respeito de sua pr??tica profissional e pessoal, conectando-as com o desenvolvimento imagin??rio do Curinga e o seu efeito provocado no ator.

Background: Blockchain have attracted a lot of attention in the last few years. It has been described as a technology that will increase the effectiveness of monitoring and improve the auditability of transactions which would have great implications for accountants and auditors. Purpose: The purpose of this study is to investigate how blockchain can help auditors to implement audit trails. The aim is to increase awareness about what the blockchain technology is, investigate if blockchain can be used in audit trails and if it can contribute to more cost-effective, reliable and secure audit trail. Methodology: The study is an exploratory research to increase the knowledge and understanding of blockchain and audit trails. It has a qualitative approach where primary data is collected from a semi-structured interview with Deloitte. Conclusion: The results indicates that there exists a gap in the literature of previously research on blockchain in relation to audit trails that needs further investigation. Furthermore, this study shows that blockchain is a technology with a lot of potential, but knowledge is still limited. This study concludes that there is too little research conducted to be able to provide any conclusive evidence. Due to findings and limitations of this research, suggestions for further research is provided.

Background:           Blockchain technology is recently receiving a lot of attention from researchers as well as from many different industries. There are promising application areas for the logistics sector like digital document exchange and tracking of goods, but there is no existing research on these topics. This thesis aims to contribute to the research of information systems in logistics in combination with Blockchain technology.     Purpose:                  The purpose of this research is to explore the capabilities of Blockchain technology regarding the concepts of privacy, transparency and trust. In addition, the requirements of information systems in logistics regarding the mentioned concepts are studied and brought in relation to the capabilities of Blockchain technology. The goal is to contribute to a theoretical discussion on the role of Blockchain technology in improving the flow of goods and the flow of information in logistics.   Method:                   The research is carried out in the form of an explorative case study. Blockchain technology has not been studied previously in a logistics setting and therefore, an inductive research approach is chosen by using thematic analysis. The case study is based on a pilot test which had the goal to facilitate a Blockchain to exchange documents and track shipments.   Conclusion:             The findings reflect that the research on Blockchain technology is still in its infancy and that it still takes several years to facilitate the technology in a productive environment. The Blockchain has the capabilities to meet the requirements of information systems in logistics due to the ability to create trust and establish an organisation overarching platform to exchange information.

Airline disruption management traditionally seeks to address three problem dimensions – aircraft scheduling, crew scheduling, and passenger scheduling – in that order. However, current efforts have, at most, only addressed the first two con-currently and do not account for the propagative effects that uncertain scheduling outcomes in one dimension can have on another. Uncertainties in scheduling out-comes originate from random disruption events (like inclement weather and aircraft malfunction), the order in which they occur, and how they are resolved. As such, these uncertainties propagate through all problem dimensions of airline disruption management on day of operation. Existing approaches for airline operations recovery include human specialists who decide on the necessary corrective actions to airline schedule disruptions on the day of operation. However, human specialists are limited in their ability to process copious amounts of information, necessary to make robust decisions that simultaneously address all three problem dimensions in operations recovery. Therefore, there is a need to augment the decision-making capabilities of a human specialist with quantitative and qualitative tools that can rationalize complex interactions amongst the three dimensions in airline operations recovery, and provide objective insights to the specialists in the Airline Operations Control Center (AOCC).To this effect, this dissertation provides a discussion of an agnostic and systematic paradigm for enabling simultaneously-integrated recovery of all problem dimensions in airline disruption management, through an intelligent multi-agent system that employs principles from artificial intelligence and distributed ledger technology.

Distributed ledger technology (DLT) stands to benefit industries such as financial services with transparency and censorship resistance. DLT systems need to be scalable to handle mass user adoption. Mass user adoption is required to demonstrate the true value of DLT. This dissertation first analyses scalability in ethereum and EOS. Currently, ethereum 1.0 uses proof of work (PoW) and handles only 14 transactions per second (tps) compared to Visa's peak 47 000 tps. Ethereum 2.0, known as Serenity, introduces sharding, proof of stake (Casper), plasma and state channels in and effort to scale the system. EOS uses a delegated proof of stake (DPoS) protocol, where 21 super-nodes, termed ‘block producers' (BPs), facilitate consensus, bringing about significant scalability improvements (4000 tps). The trade-off is decentralisation. EOS is not sufficiently decentralised because the BPs yield significant power, but are not diverse. This dissertation conducts an empirical analysis using unsupervised machine learning to show that there is a high probability collusion is occurring between certain BPs. It then suggests possible protocol alterations such as inverse vote weighting that could curb adverse voting behaviour in DPoS. It further analyses whether universities are suitable BP's before mapping out required steps for universities to become block producers (leading to improved decentralisation in EOS)

This diploma thesis deals with the creation of a design for the utilization of blockchain technology in a corporate environment. The main goal of this work is to create a proposal for a business process and its implementation in a specific blockchain platform. The analysis of the current state of the process describes current process and company’s requirements for the functionality of new technology. In the design part of the work, I compared specific blockchain platforms. As a result of this part I chose the most suitable solution for the implementation of my proposal. This chapter further includes the design of a methodology for verifying whether the process is suitable for the implementation of a blockchain technology or not. Moreover, it describes how to proceed when choosing a suitable solution and highlights its key factors.

This study investigates the viability of revising The Update Framework (TUF) to be implemented on a distributed ledger called IOTA. TUF is a framework that is becoming the de facto standard for securing update systems. The design for the revised Update Framework, called TUFT, is thoroughly explained and examined. A security analysis  as well as a performance analysis are made for the proposed design and prototype respectivly. Security-wise, TUFT is determined to be more secure than the original framework. On the other hand, TUFT is shown to be slower than the original TUF, with some scalability issues due to the requirement to fetch the whole update history for a repository. To accompany a wider range of software we also introduce new features in TUFT that provide versioning and mapping. The work done shows that a distributed ledger can improve a system like TUF in regards to security, auditability, and immutability. In summary, the proposed TUFT design is promising with its new features although it is limited performance-wise in some regards. With the updates being done to the IOTA ledger, a system like TUFT could be further improved upon to reduce the performance impact.