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<p>Lack of generality in deployment of Wireless Sensor Networks gives rise to many application specific research questions. In order to maintain safe levels of radiation, a Sensor Network can be used to provide greater flexibility within the McMaster Nuclear Reactor (MNR). Sensor Networks have conventionally been deployed in natural habitat areas, and to our knowledge, this is the first attempt to model its behavior inside a research reactor. This application specific scenario provides insight in derermining the suitability of embedding Sensor Networks in nuclear reactors. Traditional networks have been designed to accommodate various applications. In this case, we believe that sensor networks, which serve a specific task, can be customized depending on the application. By tailoring a Sensor Network for the Nuclear Reactor, one will be able to maximize efficiency.</p> <p>This thesis states a set of requirements for deploying a Sensor Network in the MNR. By using these requirements, the challenges surrounding Sensor Network communications were studied. These results are to provide McMaster's Health Physics department with the proper guidance if choosing to deploy such a network. The research defines the optimal MAC, and Sensor Network routing protocols for the reactor. The metrics used to determine optimality are reliability, latency, scalability, and lifetime. The approach to determine the suitability of sensor networks in the MNR is a discrete-event simulator called J-Sim. J-Sim is extended to simulate the various protocols that were studied in this research including One-Hop, Multi-Hop, LEACH, TDMA, and CSMA. Results indicate that a modified version of LEACH, called MNRLEACH, best suits the needs of the McMaster Nuclear Reactor.</p> / Master of Science (MSc)

<p>Sensitivity of clinical data and strict rules regarding data sharing have caused privacy and security to be critical requirements for using patient profiles in distributed healthcare environments. The amalgamation of new information technology with traditional healthcare workflows for sharing patient profiles has made the whole system vulnerable to privacy and security breaches. Standardization organizations are developing specifications to satisfy the required privacy and security requirements. In this thesis we present a novel access control model based on a framework designed for data and service interoperability in the healthcare domain. The proposed model for customizable access control captures the dynamic behavior of the user and determines access rights accordingly. The model is generic and flexible in the sense that an access control engine dynamically receives security effective factors from the subject user, and identifies the privilege level in accessing data using different specialized components within the engine. Standard data representation formats and ontologies are used to make the model compatible with different healthcare environments. The access control engine employs an approach to follow the user's behavior and navigates between engine components to provide the user 's privilege to access a resource. A simulation environment is implemented to evaluate and test the proposed model.</p> / Master of Science (MSc)

<p>Pixel values in MR images are linear combinations of contributions from multiple tissue fractions. The tissue fractions can be recovered using the Moore-Penrose pseudo-inverse if the tissue parameters are known, or can be deduced using machine learning. Acquiring sufficiently many source images may be too time consuming for some applications. In this thesis, we show how tissue fractions can be recovered from partial k-space data, collected in a fraction of the time required for a full set of experiments. The key to reaching significant sample reductions is the use of regularization. As an additional benefit, regularizing the inverse problem for tissue fractions also reduces the sensitivity to measurement noise. Numerical simulations are presented showing the effectiveness of the method, showing three tissue types. Clinically, this corresponds to liver imaging, in which normal liver, fatty liver and blood would need to be included in a model, in order to get an accurate fatty liver ratio, because all three overlap in liver pixels (via partial voluming).</p> / Master of Science (MSc)

<p>The problem of computing winning strategies in games has yielded many important results with applications in fields such as computer science, economics, and mathematics. For example, "Online" games, where the input is received on the fly are used to model process scheduling and paging algorithms. The concept of Nash Equilibrium has implications in economic theory, and Ehrenfeuct-Frass games are used to check whether two structures are isomorphic.</p> <p>In this thesis we are concerned with Partially-Ordered Set (Poset) games. We present two new methods for proving that computing winning strategies for the game of Chomp is in PSPACE. \Ne also present the idea of "Game Completeness", and give an overview of efforts to translate any poset game into an equivalent configuration of Chomp. Finally, we show how Skelley's bounded arithmetic theory W¹₁ can be applied to Chomp, and the consequences of expressing the existence of a winning strategy for the first player in Chomp in simpler arithmetic theories. In short, the contributions of this thesis are as follows:</p> <p>1. A new method for showing poset games in PSPACE, via a polynomial-time (logarithmic-space) reduction to the game of Geography.</p> <p>2. Attempts at a reduction from Geography to poset games, and implications to whether poset games are PSPACE-complete.</p> <p>3. A bounded-arithmetic formulation of the existence of a winning strategy for the first player in Chomp.</p> <p>4. A definition of the concept of Game Completeness, and a translation from treelike poset games to a modified version of Chomp.</p> / Master of Applied Science (MASc)

We extend the original selfish routing setting by introducing users who are oblivious to congestion. Selfish routing captures only the behavior of selfish users, who choose the cheapest route based on the current traffic congestion without caring about the effects of their routing on their fellow users. However, it is more likely that a certain number of network users will be oblivious to congestion. For example, data from low-level QoS services will be routed on predefined routes with no adaptability to network congestion, while data from high-level QoS services will be routed on the fastest paths available. Networks with selfish users may lead to a stable state or Nash equilibrium, where no selfish users can decrease his or her travel time by changing his or her route unilaterally. Traffic equilibria refer to Nash equilibria in networks only with selfish users, and oblivious equilibria refer to Nash equilibria in networks with both oblivious users and selfish users. We study the performance degradation of networks at oblivious equilibrium with respect to the optimal performance. Our model has a fraction a of oblivious users, who choose predefined shortest paths on the network, and the remaining are selfish users. Considering networks with linear latency functions, first we study parallel links networks with two nodes, and then general topologies. We provide two tight upper bounds of the price of anarchy, which is the ratio of the worst total cost experienced by both oblivious users and selfish users, over the optimal total cost when all users are centrally coordinated. Our bounds depend on network parameters such as a, the total demand, the latency functions, the total cost of a traffic equilibrium flow, and the total cost of an optimal flow. The dependency of our bounds on network parameters seems to be inevitable considering the fact that the price of anarchy can be arbitrary large depending on network parameters as oblivious users may choose an arbitrarily expensive path. / Master of Science (MSc)

Approved for public release; distribution is unlimited / In the past ten years, military operations, as now evident in Iraq, involve both joint- allied and coalition forces. The evolving joint- and coalition-warfare environment presents coordination challenges. Collaborative tools can ease the difficulties in meeting these challenges by enabling highly interactive work to be performed by individuals not necessarily geographically co-located. Collaborative tools will revolutionize the manner in which distributed warfighters interact and inform each other of the missionplanning progress and situation assessment. These systems allow warfighters to integrate tactical information with key combat-support logistics data in both joint- and coalition-warfare environments. Countless collaboration tools and knowledge management systems exist today. Unfortunately, industry has developed these tools and systems for use primarily in exclusive communities of interests, services or agencies. The end result is a proliferation of tools that have not been designed to operate under all network conditions. Since network conditions are not standardized in the joint- and coalition-warfare environment, it is necessary to determine if a collaborative tool can perform under limited-bandwidth and latency conditions. Currently, there are neither evaluation criteria nor methodologies for evaluating collaborative tools with respect to performance reliability. This thesis proposes a test methodology for evaluation of performance reliability of collaborative tools, and demonstrates the effectiveness of the methodology with a case study of the performance evaluation of the InfoWorkSpace collaborative tool.

M.Com. (Informatics) / Research into formalised methods for software engineering has resulted in many solutions to the known problems of software development. One of these problems is the difficulty involved In managing the cost of software development. Though attempts are made to solve the problem of budget and schedule overruns during project management, there still seems to be a lack of useful formal methods and approaches. In this dissertation such a formalised approach is presented. This approach Is based on the principle that cost should be actively managed just like any other aspect of software development. Within this framework the management of cost is defined as a process of identifying, estimating, measuring and controlling those factors that Influence the cost of development. Many methods exists through which the estimation of cost can be facilitated. The fact that such methods are available does not seem to solve the problem because cost management Involves more than just cost estimation. The research done to formalise this approach includes a discussion on the background of software engineering and the state of the science. It also includes an investigation Into the use of development metrics. The cost of software development is analyzed to determine the influence of different environmental factors on cost. A few estimation models are also discussed to determine the useability of such methods during cost management. A synopsis of how these subjects are covered In this dissertation is as follows: Chapter one serves as an Introduction to the research by giving a background to the development of software engineering. The limitations of current practices are emphasized and certain research questions are formulated. Chapter two discusses formal methods of development in the form of process models as a basis for the management of development cost. This chapter also analyzes development metrics as a method of measurement during development and cost management. The analysis provides as a framework for the identification and application of metrics during the process of cost management. Chapter three defines the extent of development cost and analyzes all factors contributing to the cost of software. The chapter discusses each of these factors by examining the possible influence of each on the effort of development and the Interdependence of these factors. Chapter four discusses a case study to be applied during discussions In the rest of the dissertation. Chapter five examines different approaches to the estimation of software development cost. The chapter serves as an introduction to subsequent chapters that deal with specific estimation models. Chapter six discusses an estimation model developed by Blokdijk. The chapter gives an overview of the principles Involved in and the application of the model.

Made available in DSpace on 2019-03-30T00:14:16Z (GMT). No. of bitstreams: 0 Previous issue date: 2017-12-22 / Lately Blockchain technology has been gaining market visibility. The popularization of this concept can be attributed to the exponential success of the Bitcoin cryptocurrency, launched in 2008 by Satoshi Nakamoto. The disruptive vision of this technology and the diverse possibilities of application in different businesses have been generating a series of changes and investments in the market, especially the financial sector. The emergence of several Fintechs (Startups in the financial sector) focused on software using Blockchain demonstrates the investments made to advance this technology. In this work, a bibliographical research was carried out in order to understand the state of the art of Blockchain and an experience of use was developed, where an application was developed using this technology, being source of information for the detailed definition of a software development process, based on Lean Startup, to support startups working with projects involving Blockchain. Keywords: Software Development, Process, Blockchain, Startup. / Ultimamente a tecnologia de Cadeia de blocos (Blockchain) vem ganhando visibilidade no mercado. A popularização deste conceito pode ser atribuída ao sucesso exponencial da criptomoeda Bitcoin, lançada em 2008 por Satoshi Nakamoto. A visão disruptiva dessa tecnologia e as diversas possibilidades de aplicação em negócios distintos vêm gerando uma série de mudanças e investimentos no mercado, destacando-se principalmente o setor financeiro. O surgimento de diversas Fintechs (Startups do setor financeiro) voltadas a softwares que utilizam Blockchain demonstra os investimentos ocorridos para o avanço dessa tecnologia. Neste trabalho, foi realizada uma pesquisa bibliográfica a fim de compreender o estado da arte de Blockchain e foi também executada uma experiência de uso, onde foi desenvolvido um aplicativo utilizando esta tecnologia, sendo fonte de informações para a definição detalhada de um processo de desenvolvimento de software, baseado em Lean Startup, para apoiar startups a trabalharem com projetos que envolvam Blockchain. Palavras-chave: Desenvolvimento de Software, Processo, Blockchain, Startups.