This study contributes to an understanding of how coherence can be assigned or constructed by participants in authentic multiparty conversational interaction. Coherence is analysed as a type of organisation relevant for the making of meaning in situated interaction, but also in retrospect from a third party's (or analyst's) perspective; it is both constructed and reconstructed. Important questions are: what makes multiparty talk hold together, what do a number of participants in conversation (have to) do in order to sustain coherence, and in what senses can multiparty conversations be argued to be coherent? A notion of episode is (re)introduced as a unit of natural social interaction, manifest at a structurally intermediate, or a global. level of conversation. The use of episode implies that coherence, a pragmatic phenomenon, steadily encompasses text, i.e. talk, context(s) and actions, and sense-making practices invoking contexts during the progression of interaction. This reflects the reciprocal relations between länguage, social interaction, and cognition. Also, a coding method of coherence has been developed, Topical Episode Analysis (abbreviated as TEA). The thesis explores the concept of episode and its place among units of interaction, and describes the episode structure and coherence-making in some specific activity types. The empirical material used, 24 multiparty conversations making up a total of 1500 episodes, consists of dinner conversations among peers, multi-generational family gatherings (involving aphasics), radio talk shows, and conversations recorded at a centre aimed for elderly people (with symptoms of dementia). In all conversations, conversing is a main activity. Both qualitative and quantitative analyses have been carried out. Results include the following points: (i) coherence in multiparty conversation can be regarded as a co-construction; (ii) coherence is accomplished through the invoking of contexts (cotext, situation, and background knowledge), implying that coherence is an attribute of activities in context and not only 'text'; (iii) coherence-making is the unmarked case in authentic conversation and incoherence or non-coherence appear to be theoretical constructs; (iv) coherence patterns are activityspecific; (v) coherence is multilayered, consisting of one local and several global levels; (vi) coherence is constructed through a division of communicative labour, suggesting that also people with communicative impairments contribute to coherence-making.

The number of opportunities for cooperative computation has exponentially been increasing with growing interaction via Internet technologies. These computations could occur between trusted partners, between partially trusted partners, or even between competitors. Most of the time, the communicating parties may not want to disclose their private data to the other principal while taking the advantage of collaboration, hence concentrating on the results rather than private and perhaps useless data values. For performing such computations, one party must know inputs from all the participants / however if none of the parties can be trusted enough to know all the inputs, privacy will become a primary concern. Hence the techniques for Secure Multiparty Computation (SMC) are quite relevant and practical to overcome such kind of privacy gaps. The subject of SMC has evolved from earlier solutions of combinational logic circuits to the recent proposals of anonymity-enabled computation. In this thesis, we put together the significant research that has been carried out on SMC. We demonstrate the concept by concentrating on a specific technique called Oblivious Polynomial Evaluation (OPE) together with concrete examples. We put critical issues, challenges and the level of adaptation achieved before the researchers. We also provide some future research opportunities based on the literature survey.

<p>Internet Telephony defined as real time voice or multimediacommunications over packet switched networks dates back to theearly days of the Internet. ARPA's Network SecureCommunications project had implemented, as early as December1973, an infrastructure for local and transnet real time voicecommunication. Two main sets of standards have emerged: H. 323from the ITU-T and the session initiation protocol (SIP) fromthe Internet Engineering Task Force (IETF). Both includespecifications for value added services. Value added services,or more simply services, are critical to service providers'survival and success. Unfortunately, the service architecturesthat come with the ITU-T and the IETF sets of standards arerather weak. Although they are constantly evolving,alternatives and complements need to be researched. This thesiswhich is made up of a formal dissertation and 6 appendices,proposes a novel mobile agent based service architecture forInternet Telephony. The architecture addresses the issues noneof the existing architectures solves in a satisfactory manner.Furthermore it adds mobile agents to the panoply of servicecreation tools. The appendices are reprints of articlespublished in refereed magazines/journals or under considerationfor publication. The formal dissertation is a summary of thepublications. A consistent and comprehensive set ofrequirements are derived. They are TINA-C flavored, but adaptedto Internet Telephony. They are used to critically reviewrelated work and also used to motivate the use of mobile agentsas the pillars of a novel architecture. The components of thisnovel architecture are identified. The key component is themobile service agent. It acts as a folder and carriesservice(s) to which the end-user has subscribed. Mobile serviceagents need to be upgraded when new versions of service logicare available and when end-users make changes to service data.This thesis proposes a novel upgrading framework. The currentInternet infrastructure comprises a wide range of hosts. Mobileagent platforms are now available for most of thesehosts/clients including memory/processing power constrainedPDAs. Our mobile service agents need to adapt to hostvariability when roaming. A novel adaptivity framework is alsoproposed. These two frameworks are general and can be appliedto any other mobile agent which meets a basic set ofassumptions. A key advantage of a mobile agent based servicearchitecture is that it enables the developement of mobileagent based services. The thesis proposes a novel mobile agentbased multi-party session scheduler. The feasibility and theadvantages of the architecture proposed by this thesis havebeen demonstrated by a prototype on which measurements havebeen made. Future work includes the addition of a securityframework to the architecture, and refinenements to theupgrading and adaptivity frameworks. More mobile agent basedservices, especially mobile multi agent based services willalso be developed.</p>

In todays heterogeneous network environment, there is a growing demand for distrusted parties to jointly execute distributed algorithms on private data whose secrecy needed to be safeguarded. Platforms that support such computation on image processing purposes are called secure image processing protocols. In this thesis, we propose a new security model, called quasi information theoretic (QIT) security. Under the proposed model efficient protocols on two basic image processing algorithms linear filtering and thresholding are developed. For both problems we consider two situations: 1) only two parties are involved where one holds the data and the other possesses the processing algorithm; 2) an additional non-colluding third party exists. Experiments show that our proposed protocols improved the computational time significantly compared with the classical cryptographical couterparts as well as providing reasonable amount of security as proved in the thesis

Many scholarly and policy evaluations of governance in Uganda have blamed limited commitment to democracy in the country squarely on the shoulders of state leaders. This dissertation considers a broader range of explanations and raises questions about the limited understanding of democracy expressed in the prevailing literature. It does so by considering historical contexts, international and global structures, and the relationship between local political cultures and the contested concept of democracy. Claims about democracy and good governance, it suggests, are used to justify very narrow procedural prescriptions for the domestic state on the basis of a systematic neglect of Uganda’s specific political history and the structural contexts in which the Ugandan state can act. More specifically, this dissertation engages with one of the key controversies in the literature on the politics of development, that concerning the degree to which accounts of democracy favoured by the most powerful states should guide attempts to create democratic institutions elsewhere. It argues that at least some of the factors that are often used to explain the failure of democracy in Uganda can be better explained in terms of two dynamics that have been downplayed in the relevant literature: competition between different understandings of how democracy should be understood in principle; and the international conditions under which attempts to impose one specific account of democracy - multiparty representation – have marginalized other possibilities. These dynamics have undermined processes that arguably attempt to construct forms of democracy that respond to very specific socio-cultural conditions. Fundamental disputes about how democracy should be understood are already familiar from the history of democracy in Western societies, where struggles to impose some forms of democracy over others have defined much of the character of modern politics. The importance of the international or global dimension of democratic politics has received less attention, even in relation to Western societies, but is especially significant in relation to Africa’s political history and its position in the world. After reviewing the history of struggles over forms of governance in Uganda, this dissertation explores a series of unique open-ended interviews carried out in 2009 with important political actors in Uganda. On this basis, it argues for the ongoing centrality both of the always contested character of democracy and of attempts to impose particular accounts of democracy through internationalised and globalised structures. An appreciation of both dynamics, especially in the historical context that has been downplayed in much of the literature, offers a better scholarly ground on which to evaluate contemporary politics in Uganda than the choice between multiparty systems and dictatorship that remains influential in discussions of the Ugandan case. Such an appreciation is in keeping with important recent attempts to think about the possibilities of democracy in Uganda in postcolonial terms and to resist the forms of neocolonial politics that are examined here as a ‘politics of dispensation.’ / Graduate / 0615 / 0616 / sabina@uvic.ca

Many scholarly and policy evaluations of governance in Uganda have blamed limited commitment to democracy in the country squarely on the shoulders of state leaders. This dissertation considers a broader range of explanations and raises questions about the limited understanding of democracy expressed in the prevailing literature. It does so by considering historical contexts, international and global structures, and the relationship between local political cultures and the contested concept of democracy. Claims about democracy and good governance, it suggests, are used to justify very narrow procedural prescriptions for the domestic state on the basis of a systematic neglect of Uganda’s specific political history and the structural contexts in which the Ugandan state can act. More specifically, this dissertation engages with one of the key controversies in the literature on the politics of development, that concerning the degree to which accounts of democracy favoured by the most powerful states should guide attempts to create democratic institutions elsewhere. It argues that at least some of the factors that are often used to explain the failure of democracy in Uganda can be better explained in terms of two dynamics that have been downplayed in the relevant literature: competition between different understandings of how democracy should be understood in principle; and the international conditions under which attempts to impose one specific account of democracy - multiparty representation – have marginalized other possibilities. These dynamics have undermined processes that arguably attempt to construct forms of democracy that respond to very specific socio-cultural conditions. Fundamental disputes about how democracy should be understood are already familiar from the history of democracy in Western societies, where struggles to impose some forms of democracy over others have defined much of the character of modern politics. The importance of the international or global dimension of democratic politics has received less attention, even in relation to Western societies, but is especially significant in relation to Africa’s political history and its position in the world. After reviewing the history of struggles over forms of governance in Uganda, this dissertation explores a series of unique open-ended interviews carried out in 2009 with important political actors in Uganda. On this basis, it argues for the ongoing centrality both of the always contested character of democracy and of attempts to impose particular accounts of democracy through internationalised and globalised structures. An appreciation of both dynamics, especially in the historical context that has been downplayed in much of the literature, offers a better scholarly ground on which to evaluate contemporary politics in Uganda than the choice between multiparty systems and dictatorship that remains influential in discussions of the Ugandan case. Such an appreciation is in keeping with important recent attempts to think about the possibilities of democracy in Uganda in postcolonial terms and to resist the forms of neocolonial politics that are examined here as a ‘politics of dispensation.’ / Graduate / 0615 / 0616 / sabina@uvic.ca

O principal objetivo deste trabalho é mostrar que, no presidencialismo multipartidário brasileiro, as políticas públicas implementadas pelo Executivo são resultantes do processo de agregação de preferências dos diferentes atores partidários que integram o gabinete de governo. Posto que os partidos aceitam integrar coalizões de governo em função da expectativa de agregar suas preferências à agenda de políticas do Executivo, os conflitos intragabinete são derivados da não efetivação desta expectativa. Argumento que, embora sejam delegadas aos integrantes do gabinete áreas ministeriais específicas, os partidos da coalizão monitoram as áreas de policy dos seus parceiros de governo, na tentativa de diminuir a assimetria de informação e agregar suas preferências às políticas que lhes interessam. Para tanto, investigo de que forma os parlamentares utilizam as suas prerrogativas de controle horizontal - [i] Requerimentos de Informação (RIC), [ii] Propostas de Fiscalização e Controle (PFC) e [iii] Projeto de Decreto Legislativo (PDC) - para obter informações sobre a implementação de políticas nos ministérios dos partidos parceiros do gabinete. A análise compreende o período entre 1995 e 2014, nos governos Fernando Henrique Cardoso (FHC), Luís Inácio da Silva (LULA) e Dilma Rousseff (DILMA). As evidências apresentadas neste trabalho sugerem que a taxa de controle horizontal intragabinete varia positivamente com o grau de dispersão de preferências dos partidos representados no governo. Em função da motivação policyseeking dos atores que integram o gabinete, os partidos que possuem mais recursos para a implementação de políticas públicas são também aqueles que recebem o maior volume de controle dos seus parceiros de gabinete. Como consequência, são os partidos da coalizão de governo os principais responsáveis por monitorar as ações de implementação de políticas públicas do Executivo. Ao contrário do que ocorre no momento de formulação das políticas no gabinete e no parlamento, o peso legislativo dos partidos integrantes do governo importa pouco para a capacidade destes atores agregarem suas preferências às policies. Isso explica o que ganham os partidos que aceitam integrar as coalizões de governo e revela qual o mecanismo que viabiliza a manutenção de um pacto político firmado entre atores com preferências distintas e heterogêneas. / The aim of this study is to show that public policies implemented by the executive branch in the Brazilian multiparty presidential system are the result of aggregating the preferences of different party members within the government cabinet. Parties agree to integrate into the coalition government because they expect to be able to add their preferences to the government policy agenda. However, when parties are unable to influence the policy agenda, it often results in intra-cabinet conflicts. I argue that, although the chief executive delegates specific portfolios to each cabinet member, the parties scrutinize the policies carried out by the government members in an attempt to reduce the asymmetric information and add their preferences to policies that concern them. For this purpose, I investigate how legislative membres use their horizontal control prerogative - [i] Requerimentos de Informação (RIC), [ii] Propostas de Fiscalização e Controle (PFC) e [iii] Projeto de Decreto Legislativo (PDC) - to obtain information on the policy process of policy implementation within the portfolios held by cabinet members. This study analyzes data from 1995 to 2014, in the Fernando Henrique Cardoso (FHC), Luís Inácio da Silva (LULA) and Dilma Rousseff (DILMA) administrations. The evidence presented in this study suggests that the intra-cabinet horizontal control varies positively with the degree of dispersion of policy preferences in the cabinet government. As a result of the policy-seeking motivation of the actors who comprise the government coalition, parties with more resources for the implementation of public policies are also those that receive the greatest amount of control over other members of the cabinet. Thus, the government coalition parties are primarily responsible for monitoring the implementation of federal programs. Unlike what is observed at the time of policy formulation in the cabinet and in parliament, the proportion of coalition seats/votes a member contributed is of small importance to the ability of these actors to aggregate their prefered policies. This explains what the parties receive when they agree to integrate into the cabinet and reveals the mechanism that enables the maintenance of a political pact between actors with different and heterogeneous preferences.

<p>Research in engineering design assumes that data flows smoothly among different designers within a product realization process. This assumption is not valid in many scenarios, including when designers partner with a future competitor or when designers search for potential collaborators is hampered by an inability to share sensitive data. This information asymmetry among designers has an adverse effect on the outcomes of the product realization process. Designers need a secure yet collaborative design process that enables them to overcome these information-related risks borne from collaborators participating in their product realization process. Existing cryptographic techniques aimed at overcoming these risks are computationally intensive, making them unsuitable for heavy engineering computations such as finite element analysis (FEA). FEA is a widely used computation technique in several engineering applications, including structural analysis, heat transfer, and fluid flow. In this work, we developed a new approach, secure finite element analysis (sFEA), using which designers can perform their analysis without revealing their confidential design data to anyone, including their design collaborators even though the computed answer depends on confidential inputs from all the collaborators. sFEA is a secure, scalable, computationally lightweight, and cloud-compatible. In addition to sFEA, we developed prototypes and demonstrated that the computational framework within sFEA is general enough to be applied to different stages of the product realization process.</p>

No description available.

<p>Secure multi-party computation (MPC) enables mutually distrusting parties to compute securely over their private data. It is a natural approach for building distributed applications with strong privacy guarantees, and it has been used in more and more real-world privacy-preserving solutions such as privacy-preserving machine learning, secure financial analysis, and secure auctions.</p> <p><br></p> <p>The typical method of MPC is to represent the function with arithmetic circuits or binary circuits, then MPC can be applied to compute each gate privately. The practicality of secure multi-party computation (MPC) has been extensively analyzed and improved over the past decade, however, we are hitting the limits of efficiency with the traditional approaches as the circuits become more complicated. Therefore, we follow the design principle of identifying and constructing fast and provably-secure MPC protocols to evaluate useful high-level algebraic abstractions; thus, improving the efficiency of all applications relying on them. </p> <p><br></p> <p>To begin with, we construct an MPC protocol to efficiently evaluate the powers of a secret value. Then we use it as a building block to form a secure mixing protocol, which can be directly used for anonymous broadcast communication. We propose two different protocols to achieve secure mixing offering different tradeoffs between local computation and communication. Meanwhile, we study the necessity of robustness and fairness in many use cases, and provide these properties to general MPC protocols. As a follow-up work in this direction, we design more efficient MPC protocols for anonymous communication through the use of permutation matrices. We provide three variants targeting different MPC frameworks and input volumes. Besides, as the core of our protocols is a secure random permutation, our protocol is of independent interest to more applications such as secure sorting and secure two-way communication.</p> <p><br></p> <p>Meanwhile, we propose the solution and analysis for another useful arithmetic operation: secure multi-variable high-degree polynomial evaluation over both scalar and matrices. Secure polynomial evaluation is a basic operation in many applications including (but not limited to) privacy-preserving machine learning, secure Markov process evaluation, and non-linear function approximation. In this work, we illustrate how our protocol can be used to efficiently evaluate decision tree models, with both the client input and the tree models being private. We implement the prototypes of this idea and the benchmark shows that the polynomial evaluation becomes significantly faster and this makes the secure comparison the only bottleneck. Therefore, as a follow-up work, we design novel protocols to evaluate secure comparison efficiently with the help of pre-computed function tables. We implement and test this idea using Falcon, a state-of-the-art privacy-preserving machine learning framework and the benchmark results illustrate that we get significant performance improvement by simply replacing their secure comparison protocol with ours.</p> <p><br></p>