<p>Recent advancements in reactor designs offer new capabilities, not seen before. To increase flexibility and reduce operation and maintenance costs, modern reactor designs (e.g., microreactors, SMRs) embrace new technologies which would allow revolutionary operational concepts such as remote monitoring and control, semiautonomous or near-autonomous operation, and two-way communications for real-time integration with the upcoming smart electric grid. Such a continuous data transmission from and towards a reactor site could introduce vulnerabilities and necessitates the prioritization of cybersecurity. However, classical IT-based encryption schemes have been shown to be vulnerable to cyberattacks, as they rely on computational complexity. It has been shown (e.g., Shor’s algorithm) that with the advent of quantum computing practically any asymmetric encryption could be broken within hours. To address this challenge, this thesis explores the feasibility of applying Quantum Key Distribution (QKD) to nuclear reactor communications. QKD is a physical-layer security scheme relying on the laws of quantum mechanics instead of mathematical complexity. QKD promises not only unconditional security but also detection of potential intrusion, as it allows the communication parties to become aware of eavesdropping. To test the proposed hypothesis, a novel simulation tool (NuQKD) was developed to allow for real-time simulation of the BB84 QKD protocol between two remote terminals. NuQKD offers new capabilities not currently available in other simulation tools including true random numbers, modeling of equipment imperfections, and modeling of fiber optic and free space quantum channels. NuQKD was rigorously benchmarked against analytical, numerical and experimental data. Then, a reference nuclear reactor scenario is proposed that is generic enough to cover various communications links internal and external to a reactor site. Using NuQKD, the internal and external data links of the nuclear reactor reference scenario were modeled, and the receiver operating characteristics (ROC) curves were calculated for various QKD configurations. It was found that that QKD can provide adequate key rates with low false alarm rates and has the potential of addressing nuclear industry’s high standards of confidentiality up to 100 km distance using fiber optic. As a result, QKD is shown to be compatible with the existing and future point-to-point reactor communication architectures. These results motivate further study of quantum communications for nuclear reactors.</p>

Recent years have shown a growing concern over increasing traffic volume worldwide. The insufficient road capacity and the resulting congestions have become major problems in many urban areas. Congestions negatively impact the economy, the environment and the health of the population as well as the drivers satisfaction. Current solutions to this topical and timely problem rely on the exploitation of Intelligent Transportation Systems (ITS) technologies. ITS urban traffic management involves the collection and processing of a large amount of geographically distributed information to control distributed infrastructure and individual vehicles. The distributed nature of the problem prompted the development of a novel, scalable ITS-Cloud platform. The ITS-Cloud organises the processing and manages distributed data sources to provide traffic management methods with more accurate information about the state of the traffic. A new approach to service allocation, derived from the existing cloud and grid computing approaches, was created to address the unique needs of ITS traffic management. The ITS-Cloud hosts the collection of software services that form the Cloud based Traffic Management System (CTMS). CTMS combines intersection control algorithms with intersection approach advices to the vehicles and dynamic routing. The CTMS contains a novel Two-Step traffic management method that relies on the ITS-Cloud to deliver a detailed traffic simulation image and integrates an adaptive intersection control algorithm with a microscopic prediction mechanism. It is the first method able to perform simultaneous adaptive intersection control and intersection approach optimization. The Two-Step method builds on a novel pressure based adaptive intersection control algorithm as well as two new traffic prediction schemes. The developed traffic management system was evaluated using a new microscopic traffic simulation tool tightly integrated with the ITS-Cloud. The novel traffic management approaches were shown to outperform benchmark methods for a realistic range of traffic conditions and road network configurations. Unique to the work was the investigation of interactions between ITS components.

Zugl.: Saarbrücken, Univ., Diss., 2006

Thesis (Ph.D)--Computing, Georgia Institute of Technology, 2009. / Committee Chair: Stasko, John T.; Committee Member: Edwards, Keith; Committee Member: Greenberg, Saul; Committee Member: Grinter, Beki; Committee Member: Guzdial, Mark. Part of the SMARTech Electronic Thesis and Dissertation Collection.

Thesis (M.Sc.)--University of Waikato, 2007. / Title from PDF cover (viewed May 15, 2009) Includes bibliographical references (p. 99-100)

Thesis (M.S.)--Florida State University, 2006. / Advisor: Yassir AbdelRazig, Florida State University, College of Engineering, Dept. of Civil and Environmental Engineering. Title and description from dissertation home page (viewed Sept. 15, 2006). Document formatted into pages; contains xiii, 341 pages. Includes bibliographical references.

Developments in electronics, computing and communication technologies have transformed IT systems from desktop and tightly coupled mainframe computers of the past to modern day highly complex distributed systems. These ICT systems interact with humans at a much advanced level than what was envisaged during the early years of computer development. The ICT systems of today have gone through various phases of developments by absorbing intermediate and modern day concepts such as networked computing, utility, on demand and autonomic computing, virtualisation and so on. We now live in a ubiquitous computing and digital economy era where computing systems have penetrated into the human lives to a degree where these systems are becoming invisible. The price of these developments is in the increased costs, higher risks and higher complexity. There is a compelling need to study these emerging systems, their applications, and the emerging market sectors that they are penetrating into. Motivated by the challenges and opportunities offered by the modern day ICT technologies, we aim in this thesis to explore the major technological developments that have happened in the ICT systems during this century with a focus on developing techniques to manage applied ICT systems in digital economy. In the process, we wish to also touch on the evolution of ICT systems and discuss these in context of the state of the art technologies and applications. We have identified the two most transformative technologies of this century, grid computing and cloud computing, and two application areas, intelligent healthcare and transportation systems. The contribution of this thesis is multidisciplinary in four broad areas. Firstly, a workload model of a grid-based ICT system in the healthcare sector is proposed and analysed using multiple healthcare organisations and applications. Secondly, an innovative intelligent system for the management of disasters in urban environments using cloud computing is proposed and analysed. Thirdly, cloud computing market sectors, applications, and workload are analysed using over 200 real life case studies. Fourthly, a detailed background and literature review is provided on grid computing and cloud computing. Finally, directions for future work are given. The work contributes in multidisciplinary fields involving healthcare, transportation, mobile computing, vehicular networking, grid, cloud, and distributed computing. The discussions presented in this thesis on the historical developments, technology and architectural details of grid computing have served to understand as to how and why grid computing was seen in the past as the global infrastructure of the future. These discussions on grid computing also provided the basis that we subsequently used to explain the background, motivations, technological details, and ongoing developments in cloud computing. The introductory chapters on grid and cloud computing, collectively, have provided an insight into the evolution of ICT systems over the last 50+ years - from mainframes to microcomputers, internet, distributed computing, cluster computing, and computing as a utility and service. The existing and proposed applications of grid and cloud computing in healthcare and transport were used to further elaborate the two technologies and the ongoing ICT developments in the digital economy. The workload models and analyses of grid and cloud computing systems can be used by the practitioners for the design and resource management of ICT systems.

This dissertation presents the design and implementation of a graphical user interface (GUI) to display spatial data in a web-based environment. The work is a case study for a web-based framework for distributed applications, the Web Computing Skeleton, using a distributed open spatial query mechanism to display the geographic data. The design is based on investigation of geographic information systems (GISs), GUI design and properties of spatial query mechanisms. The purpose ofthe GUI is to integrate information about a geographic area; display, manipulate and query geographic-based spatial data; execute queries about spatial relationships and analyse the attribute data to calculate the shortest routes for emergency response. The GUI is implemented as a Java applet embedded in a web document that communicates with the application server via generic GIS classes that provide a common interface to various GIS data sources used in the spatial query mechanism to access a geographic database. Features that are supported by the distributed open spatial query mechanism include a basic set of spatial selection criteria, spatial selection based on pointing, specification of a query window, description of a map scale and identification of a map legend. The design is based on a formal design process that includes the selection of a conceptual model, identification of task flow, major windows and dialog flow, the definition of fields and detailed window layout and finally the definition of field constraints and defaults. The conceptual model characterises the application and provides a framework for users to learn the system model. This model is conceptualised as a map that the user manipulates directly. Unlike a typical map, which just shows spatial data such as roads, cities, and country borders, the GIS links attribute data like population statistics to the spatial data. This link between the map data and the attribute data makes the GIS a powerful tool to manipulate and display data. To measure the performance of displaying spatial data, two main factors are considered, namely processing speed and display quality. Factors that affect the processing speed include the rate of data transfer from the generic GIS classes, the rate data is downloaded over the network and the speed of execution of the drawing. Two factors that influence the spatial data display quality are pixel distance and bitmap quality. The pixel distance set in the geographic database is represented by two pixels on the display screen, which affects the display quality since the pixel distance is the upper limit for display granularity. This means that setting the pixel distance is a trade-off between the processing speed and the display quality. Bitmaps are raster images that are made up of pixels or cells. To improve the raster image quality, the bitmap resolution can be adjusted to display more pixels per centimetre. / Dissertation (MSc (Computer Science))--University of Pretoria, 2007. / Computer Science / unrestricted

Orientador: Edmundo Roberto Mauro Madeira / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Computação / Made available in DSpace on 2018-08-23T07:19:08Z (GMT). No. of bitstreams: 1 OliveiraFilho_JorgeLimade_D.pdf: 4901235 bytes, checksum: e6b9bb2a16e6d8b4b4cac7d26265847a (MD5) Previous issue date: 2013 / Resumo: Atualmente há uma necessidade das pessoas estarem conectadas a todo o momento e em qualquer lugar utilizando seus MNs (Mobile Nodes) para realizarem suas tarefas. É desejável uma Internet disponível a todo instante. Porém, a integração das redes sem fio de tecnologias diferentes apresenta vários desafios, como por exemplo, manter a continuidade dos serviços que rodam no MN quando há uma troca de rede. Percebendo a demanda crescente por mobilidade e de uma necessidade de uma Internet ubíqua, o IEEE padronizou um conjunto de serviços e protocolos com o intuito de integrar as redes de diferentes tecnologias denominadas IEEE 802.21. Entretanto, não fazem parte do padrão alguns mecanismos necessários para suportar mobilidade nas redes heterogêneas, como por exemplo, o algoritmo de decisão para a escolha da rede e o mecanismo de gerência de handover. Além disso, a demanda por mobilidade exige um mecanismo de gerência diferenciado devido à heterogeneidade dos elementos e a dinâmica do ambiente das redes sem fio heterogêneas. Para lidar com esses desafios, este trabalho apresenta uma arquitetura de gerência de mobilidade cognitiva para redes sem fio heterogêneas. Essa arquitetura é baseada no IEEE 802.21 e é capaz de integrar diversas redes com tecnologias diferentes e de suportar mobilidade mantendo a continuidade dos serviços quando o MN troca de uma rede para outra. Foi desenvolvido para esta arquitetura um algoritmo cognitivo de decisão de handover que seleciona as redes baseado nas experiências prévias dos MNs. Esse algoritmo utiliza como métrica de decisão as perdas dos fluxos TCP configurados nos MNs. O módulo cognitivo embutido na arquitetura foi uma evolução do resultado de pesquisa da nossa proposta de um algoritmo cognitivo para reconfiguração dos parâmetros do IEEE 802.11, denominado CogMAC. O CogMAC é uma proposta descentralizada, ou seja, os MNs que o implementam não possuem uma visão total da rede, cada MN individualmente é capaz de monitorar o desempenho e reconfigurar os parâmetros da subcamada MAC para evitar degradação do desempenho devido a mudanças nas condições da rede. O CogMAC é avaliado através de simulações e de um testbed real e os resultados comparados confirmam sua eficácia. Já a arquitetura de gerência cognitiva é avaliada através de simulações, e os resultados são comparados com o algoritmo que prioriza a conexão das redes WiFi. Os resultados obtidos confirmam também o bom desempenho da arquitetura proposta / Abstract: The mobile nodes (MNs) have become popular nowadays, the rapid increase in the use of wireless technologies has changed the behavior of individuals and businesses in the way they communicate. Currently, there is a demand for people to be connected all time and everywhere by using their MNs to perform their tasks. It is desirable to have a ubiquitous Internet, available at any moment and everywhere. However, the integration of heterogeneous wireless networks introduces several challenges. One of the most challenging issues is service continuity during handovers. As a result of the high demand for mobility, IEEE has created a set of services and protocols in order to integrate heterogeneous networks, called IEEE 802.21. However, there are no mechanisms in the standard in order to support mobility in heterogeneous networks, such as decision algorithms and mechanisms to perform the handover. Moreover, the mobility demand requires a special management mechanism due to the elements' diversity and the dynamic environment of the heterogeneous wireless networks. In order to tackle these challenges, this work presents cognitive mobility management architecture for heterogeneous wireless networks. This architecture is based on the IEEE 802.21 and is able to integrate different networks with different technologies and supporting mobility while maintaining service continuity when the MN performs a handover. A handover decision algorithm was developed for this architecture to select networks based on the previous experiences of MNs. This algorithm uses as decision metric the TCP loss in the MNs. The cognitive module in the architecture is an evolution of research results of our proposed algorithm for reconfiguration of cognitive parameters of the IEEE 802.11, called CogMAC. The CogMAC is a completely distributed proposal capable to monitor the MAC layer performance and react to changes to avoid performance degradation. The CogMAC is evaluated by simulations and real testbed and the results are compared with the first-WiFi algorithm. This algorithm prioritizes the connection of WiFi networks. The results also confirm the good performance of the proposed architecture / Doutorado / Ciência da Computação / Doutor em Ciência da Computação

The thesis deals with an analysis of approach methods, that can be used in integration of SaaS model applications into business information systems. To this end it presents business information systems. Description of these was performed from a general viewpoint. A description of what business information systems are was provided as well as a description of their architecture and service-oriented architecture. Business information sysstems were then described from a development/operation point of view, particular phases of the corelation between business and ICT were summed up, as well as ICT service supply models and development and operation alternatives. At the end of the chapter, a description of business information system components was performed. Services were described in the next chapter - first generally, with special interest in service characteristics and categorization. Furthermore I explored the concept of 'Anything as a Service' (XaaS), providing a summary of what can be provided as a service. Then a distribution model for Software as a Service (SaaS) was described along with its characteristics, parameters, benefits and limitations. At the end of the chapter cloud computing, its characteristics and models of implementation were described and the most notable providers were presented. The next chapter contains a description of integration and is targetted mostly on the description of system integration, on the system integrator as a person, on a description of technological means, usable in the integration itself. The next chapter is dedicated to a description of integration scenarios of business IS using SaaS applications. In the next chapter, an approach to the analysis of integration scenarios is defined, based on various viewpoints. The last chapter contains an assesment of particular integration scenarios and a consequential evaluation performed along evaluation criteria.