An understanding of cryptographic protocols requires that we examine the knowledge of protocol participants and adversaries: When a participant receives a message, does she know who sent it? Does she know that the message is fresh, and not merely a replay of some old message? Does a network spy know who is talking to whom? This thesis studies logics of knowledge and cryptography. Specifically, the thesis addresses the problem of how to make the concept of knowledge reflect feasible computability within a Kripke-style semantics. The main contributions are as follows. 1. A generalized Kripke semantics for first-order epistemic logic and cryptography, where the later is modeled using private constants and arbitrary cryptographic operations, as in the Applied Pi-calculus. 2. An axiomatization of first-order epistemic logic which is sound and complete relative to an underlying theory of cryptographic terms, and to an omega-rule for quantifiers. Besides standard axioms and rules from first-order epistemic logic, the axiomatization includes some novel axioms for the interaction between knowledge and cryptography. 3. Epistemic characterizations of static equivalence and Dolev-Yao message deduction. 4. A generalization of Kripke semantics for propositional epistemic logic and symmetric cryptography. 5. Decidability, soundness and completeness for propositional BAN-like logics with respect to message passing systems. Completeness and decidability are generalised to logics induced from an arbitrary base of protocol specific assumptions. 6. An epistemic definition of message deduction. The definition lies between weaker and stronger versions of Dolev-Yao deduction, and coincides with weaker Dolev-Yao regarding all atomic messages. For composite messages, the definition withstands a well-known counterexample to Dolev-Yao deduction. 7. Protocol examples using mixes, a Crowds style protocol, and electronic payments. / QC 20100524

In this thesis, fluid flow and solute transport in heterogeneous aquifers and particularly in frac-tured rock have been investigated using Lagrangian Stochastic Advective-Reaction (LaSAR) framework. The heterogeneity of the aquifer structure or fracture configuration, as well as the various reaction/retention processes have been considered in the modelling approach. Advection and retention processes are considered to be the dominant transport processes. Monte-Carlo simulation results for transport of nonreactive tracers in 2D generic heterogeneous aquifers indicate that the travel time τ can be well approximated by a lognormal distribution up to a relative high degree of heterogeneity of the aquifers. Comparison between the Monte-Carlo simulation results and the results of first-order approximation reveals that the analytical solutions of the statistical moments of τ are valid only when the variability of the aquifer properties is small. For reactive tracers, Monte-Carlo simulations have been conducted by accounting for spatial variability of both hydraulic conductivity and one sorption parameter simultaneously. The simulation results indicate that the reaction flow path μ is a nonlinear function of distance for shorter distance, linear function for longer distance, and also that μ and τ are well correlated over the considered parameter range. The parameter β, which is purely determined by the flow condi-tions, quantifies the hydrodynamic control of retention processes for transport of tracers in frac-tures. Numerical simulations have been performed to study the statistical properties of the pa-rameter β, travel time τ and flow rate Q in a single heterogeneous fracture and in a sequence of fractures. The results of Monte-Carlo simulations indicate that the parameter β and τ are corre-lated with a power-law relationship β ∼ τm. The correlation between β and the flow rate Q have also been studied and an inverse power-law relationship β ∼ Q-m is proposed. The establishment of these relationships provides a link between the parameter β and measurable parameters τ (or Q). The LaSAR approach has been applied for prediction, evaluation and interpretation of the results of a number of tracer tests (TRUE-1, TRUE Block Scale and TRUE Block Scale Continuation) conducted by SKB at the Äspö site for tracer transport in fractures. The breakthrough curves may be predicted reasonably well, provided that the retention parameters, boundary conditions and hydraulic properties of the domain are given. The evaluation of TRUE tests indicates that the retention occurs mainly in the rim zone on site characterization time scales, while on the per-formance assessment time scale, diffusion and sorption in the unaltered rock matrix are likely to become dominant retention mechanisms. / QC 20100624

Bakgrund: 2010 presenterade SCB en undersökning om hur 403 000 jobb tillsattes (GP 2010). 79 000 av dessa tjänster tillsattes via personliga kontakter och ytterligare 100 000 där arbetsgivaren själv kontaktade den arbetssökande. Denna trend i användandet av det sociala kontaktnätet får stöd av Lena Hensvik, doktorand i nationalekonomi, i tidskriften Framtider (2012). Hon skriver att den sociala omgivningen såsom grannar, skolkamrater, tidigare kollegor och föräldrar har stor betydelse för hur vi får anställning eller inte. Hon menar att kontaktnätet är en viktig självinvestering då vårdandet av ens nätverk uppenbarligen kan underlätta jobbsökandet. Hensvik (2012) fortsätter skriva att det i dagens samhälle inte bara handlar om vem du är utan även vem du känner. Syfte: Tidigare forskning berättar att personliga kontakter är en av de faktorer som ökar anställningsbarheten. Vi vill därför ta vid där tidigare forskning slutar och göra en mer inriktad studie där vi fokuserar på personliga kontakter och kartlägger dess effekt i praktiken. Vi ämnar därför förklara personliga kontakters betydelse i samband med nyanställning av civilekonomer med examen från 2007-2012. Metod: Vi har valt att genomföra vår studie med en kvantitativ undersökningsdesign och ett deduktivt synsätt på relationen teori och forskning. Empiriska data har insamlats genom enkätundersökning. Slutsats: Vår slutsats är att personliga kontakter är användbara för civilekonomer i anställningsprocessen, att kontakterna till 90,4% leder dem till minst intervju och att kontakterna inte nödvändigtvis är de som är definierade som svaga, se Granovetters (1973, 1975) teorier om The Strength of Weak Ties. / Background: In 2010 SCB presented a survey of how 403 000 jobs were added (GP 2010). 79 000 of these were added through social contacts and another 100 000 by the employer himself who contacted the unemployed. This trend of using social contacts in the job-seeking process gets support by Hensvik, doctor in economics. In the magazine Framtider (2012) she writes that the social environment such as neighbours, class mates, former colleagues and parents have a big impact if we get an employment or not. Hensvik (2012) says that the caring of ones contacts is an important self-investment that improves your probabilities of getting an employment. She continues writing that in today’s society it’s not only important who you are but also who you know. Purpose: Previous research tells that social contacts are one of the factors that will improve your probabilities of getting employed. We will continue where previous research tends to end and aim for a more focused study where we measure the effects of using contacts in reality. The purpose of this thesis is to explain the contacts’ importance when employing former students with a Degree of Master of Science in Business and Economics. Method: We have conducted a questionnaire survey that was sent out to eight Swedish universities resulting in 100 responses. Conclusion: We have come to the conclusion that social contacts contribute in the recruitment process of former business students, that the use of contacts in 90,4% will get you far in the job-seeking process and that the helpful contacts are not necessarily the ones defined as weak ties, of which Granovetter (1973, 1975) would have argued.

This study presents the results of probabilistic modeling of plane and wedge types of slope failures, based on the &rdquo / Advance First Order Second Moment (AFOSM)&rdquo / reliability method. In both of those failure types, two different failure criteria namely, Coulomb linear and Barton Bandis non-linear failure criteria are utilized in the development of the probabilistic models. Due to the iterative nature of the AFOSM method, analyzing spreadsheets have been developed in order to carry out the computations. The developed spreadsheets are called &ldquo / Plane Slope Analyzer (PSA)&rdquo / and &ldquo / Wedge Slope Analyzer (WSA)&rdquo / . The developed probabilistic models and their spreadsheets are verified by investigating the affect of rock and slope parameters such as, ground water level, slope height, cohesion, friction angle, and joint wall compressive strength (JCS) and their distribution types on the reliability index (&amp / #946 / ), and probability of slope failure (PF). In this study, different probability distributions are used and the inverse transformation formulas of their non-normal variates to their equivalent normal ones are developed as well. In addition, the wedge failure case is also modeled by using system reliability approach and then the results of conventional probability of failure and the system reliability approach are compared.

In this study, anisotropic shells of revolution subject to symmetric and unsymmetrical static loads are analysed. In derivation of governing equations to be used in the solution, first order transverse shear effects are included in the formulation. The governing equations can be listed as kinematic equations, constitutive equations, and equations of motion. The equations of motion are derived from Hamilton&rsquo / s principle, the constitutive equations are developed under the assumptions of the classical lamination theory and the kinematic equations are based on the Reissner-Naghdi linear shell theory. In the solution method, these governing equations are manipulated and written as a set called fundamental set of equations. In order to handle anisotropy and first order transverse shear deformations, the fundamental set of equations is transformed into 20 first order ordinary differential equations using finite exponential Fourier decomposition and then solved with multisegment method of integration, after reduction of the two-point boundary value problem to a series of initial value problems. The results are compared with finite element analysis results for a number of sample cases and good agreement is found. Case studies are performed for circular cylindrical shell and truncated spherical shell geometries. While reviewing the results, effects of temperature and pressure loads, both constant and variable throughout the shell, are discussed. Some drawbacks of the first order transverse shear deformation theory are exhibited.

Traditionally, machine learning algorithms assume that training data is provided as a set of independent instances, each of which can be described as a feature vector. In contrast, many domains of interest are inherently multi-relational, consisting of entities connected by a rich set of relations. For example, the participants in a social network are linked by friendships, collaborations, and shared interests. Likewise, the users of a search engine are related by searches for similar items and clicks to shared sites. The ability to model and reason about such relations is essential not only because better predictive accuracy is achieved by exploiting this additional information, but also because frequently the goal is to predict whether a set of entities are related in a particular way. This thesis falls within the area of Statistical Relational Learning (SRL), which combines ideas from two traditions within artificial intelligence, first-order logic and probabilistic graphical models to address the challenge of learning from multi-relational data. We build on one particular SRL model, Markov logic networks (MLNs), which consist of a set of weighted first-order-logic formulae and provide a principled way of defining a probability distribution over possible worlds. We develop algorithms for learning of MLN structure both from scratch and by transferring a previously learned model, as well as an application of MLNs to the problem of Web query disambiguation. The ideas we present are unified by two main themes: the need to deal with limited training data and the use of bottom-up learning techniques. Structure learning, the task of automatically acquiring a set of dependencies among the relations in the domain, is a central problem in SRL. We introduce BUSL, an algorithm for learning MLN structure from scratch that proceeds in a more bottom-up fashion, breaking away from the tradition of top-down learning typical in SRL. Our approach first constructs a novel data structure called a Markov network template that is used to restrict the search space for clauses. Our experiments in three relational domains demonstrate that BUSL dramatically reduces the search space for clauses and attains a significantly higher accuracy than a structure learner that follows a top-down approach. Accurate and efficient structure learning can also be achieved by transferring a model obtained in a source domain related to the current target domain of interest. We view transfer as a revision task and present an algorithm that diagnoses a source MLN to determine which of its parts transfer directly to the target domain and which need to be updated. This analysis focuses the search for revisions on the incorrect portions of the source structure, thus speeding up learning. Transfer learning is particularly important when target-domain data is limited, such as when data on only a few individuals is available from domains with hundreds of entities connected by a variety of relations. We also address this challenging case and develop a general transfer learning approach that makes effective use of such limited target data in several social network domains. Finally, we develop an application of MLNs to the problem of Web query disambiguation in a more privacy-aware setting where the only information available about a user is that captured in a short search session of 5-6 previous queries on average. This setting contrasts with previous work that typically assumes the availability of long user-specific search histories. To compensate for the scarcity of user-specific information, our approach exploits the relations between users, search terms, and URLs. We demonstrate the effectiveness of our approach in the presence of noise and show that it outperforms several natural baselines on a large data set collected from the MSN search engine. / text

We study some Hölderian functional central limit theorems for the polygonal partial sum processes built on a first order nearly nonstationary autoregressive process and its least squares residuals Innovations are i.i.d. centered and at least square-integrable innovations. Two types of models are considered. For the first type model we prove that the limiting process depends on Ornstein – Uhlenbeck one. In the second type model, the convergence to Brownian motion is established in Hölder space in terms of the rate of coefficient and the integrability of the residuals. We also investigate some epidemic change in the innovations of the first order nearly nonstationary autoregressive process . We build the alpha-Hölderian uniform increments statistics based on the observations and on the least squares residuals to detect the short epidemic change in the process under consideration. Under the assumptions for innovations we find the limit of the statistics under null hypothesis, some conditions of consistency and we perform a test power analysis. / Disertacijoje nagrinėjami dalinių sumų laužčių procesai sudaryti iš pirmos eilės beveik nestacionaraus proceso bei jo mažiausių kvadratų liekanų. Inovacijos yra nepriklausomi, vienodai pasiskirstę ir bent kvadratu integruojami atsitiktiniai dydžiai su nuliniu vidurkiu. Įrodomos funkcinės ribinės teoremos šiems laužčių procesams Hiolderio erdvėje. Nagrinėjami du beveik nestacionaraus proceso atvejai. Vienu atveju įrodoma, kad ribinis procesas priklauso nuo Ornsteino–Uhlenbecko proceso. Kitu atveju, įrodomas konvergavimas į Brauno judesį Hiolderio erdvėje, atsižvelgiant į koeficiento divergavimo greitį bei inovacijų integruojamumą. Toliau nagrinėjamas epideminio pasikeitimo modelis beveik nestacionaraus pirmos eilės autoregresinio proceso inovacijoms. Nagrinėjami du modeliai. Iš stebėjimų bei liekanų konstruojama tolydžiųjų prieaugių alpha-Hiolderio statistika. Remiantis prielaidomis inovacijoms, randama statistikos ribinis procesas prie nulinės hipotezės, suderinamumo sąlygos, atliekama galios analizė.

Disertacijoje nagrinėjami dalinių sumų laužčių procesai sudaryti iš pirmos eilės beveik nestacionaraus proceso bei jo mažiausių kvadratų liekanų. Inovacijos yra nepriklausomi, vienodai pasiskirstę ir bent kvadratu integruojami atsitiktiniai dydžiai su nuliniu vidurkiu. Įrodomos funkcinės ribinės teoremos šiems laužčių procesams Hiolderio erdvėje. Nagrinėjami du beveik nestacionaraus proceso atvejai. Vienu atveju įrodoma, kad ribinis procesas priklauso nuo Ornsteino–Uhlenbecko proceso. Kitu atveju, įrodomas konvergavimas į Brauno judesį Hiolderio erdvėje, atsižvelgiant į koeficiento divergavimo greitį bei inovacijų integruojamumą. Toliau nagrinėjamas epideminio pasikeitimo modelis beveik nestacionaraus pirmos eilės autoregresinio proceso inovacijoms. Nagrinėjami du modeliai. Iš stebėjimų bei liekanų konstruojama tolydžiųjų prieaugių alpha-Hiolderio statistika. Remiantis prielaidomis inovacijoms, randama statistikos ribinis procesas prie nulinės hipotezės, suderinamumo sąlygos, atliekama galios analizė. / We study some Hölderian functional central limit theorems for the polygonal partial sum processes built on a first order nearly nonstationary autoregressive process and its least squares residuals Innovations are i.i.d. centered and at least square-integrable innovations. Two types of models are considered. For the first type model we prove that the limiting process depends on Ornstein – Uhlenbeck one. In the second type model, the convergence to Brownian motion is established in Hölder space in terms of the rate of coefficient and the integrability of the residuals. We also investigate some epidemic change in the innovations of the first order nearly nonstationary autoregressive process . We build the alpha-Hölderian uniform increments statistics based on the observations and on the least squares residuals to detect the short epidemic change in the process under consideration. Under the assumptions for innovations we find the limit of the statistics under null hypothesis, some conditions of consistency and we perform a test power analysis.

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This work focuses on the axiomatized relationships between different ontologies of varying levels of expressivity. Motivated by experiences in the decomposition of first-order logic ontologies, we partially decompose the Descriptive Ontology for Linguistic and Cognitive Engineering (DOLCE) into modules. By leveraging automated reasoning tools to semi-automatically verify the modules, we provide an account of the meta-theoretic relationships found between DOLCE and other existing ontologies. As well, we examine the composition process required to determine relationships between DOLCE modules and the Process Specification Language (PSL) ontology. Then, we propose an ontology based on the semantically-weak Computer Integrated Manufacturing Open System Architecture (CIMOSA) framework by augmenting its constructs with terminology found in PSL. Finally, we attempt to map two semantically-weak product ontologies together to analyze the applications of ontology mappings in e-commerce.