Electronic mail systems -- Security measures. Electronic mail systems -- Social aspects. Trust.
A secure system that cannot be used by real users to secure real-world processes is not really secure at all. While many believe that usability and security are diametrically opposed, a growing body of research from the field of Human-Computer...
This thesis contains material relating to two separate subjects. The first section determines when the C*-algebra affiliated to a directed graph has continuous trace. We use groupoid methods and the focus is on producing conditions on a graph that...
Hand -- Psychophysiology. Conditioned response. Hand -- Movements. Perceptual-motor processes.
The present studies examine the flexible application of two stimulus-response (SR) mappings to a single set of stimuli. The following questions are addressed: (1) Can dual mapping performance equal single mapping performance (2) Can rapid map...
Patients -- Decision making. Patients -- Attitudes. Motivation (Psychology) -- Social aspects. Preferences (Philosophy) Medical care -- Evaluation. Medical care -- Research -- Methodology. Medical care -- Decision making.
Statement of Problem
Characterizing the public's preferential attitudes towards relatively more-/less-intense elective options in ""preference-sensitive"" health care situations is particularly relevant for the prioritization policies of...
An interval order is an ordered set whose elements are in correspondence with a collection of intervals in a linearly ordered set, with disjoint intervals ordered by their relative position. The order complex of an ordered set is the simplicial...
We present a number of findings concerning groupoid dynamical systems and groupoid crossed products. The primary result is an identification of the spectrum of the groupoid crossed product when the groupoid has continuously varying abelian...
Manifolds (Mathematics) Geodesics (Mathematics) Space and time.
We investigate weak and strong refocusing of light rays in a space-time and related concepts. A strongly causal space-time ( X^ n +1 , g ) is emphstrongly refocusing at x ∈ X if there is a point y ≠ x such that all null-geodesics through y pass...
'Orthogonal modular forms are algebraic modular forms arising from lattices in quadratic spaces. In this thesis, we define orthogonal modular forms, establish their basic properties, and then apply them to a case of ternary quadratic spaces to...
Computer input-output equipment. ; Computational grids (Computer systems). ; High performance computing. ; Electronic data processing -- Distributed processing.
High-performance computing increasingly occurs on computational grids composed of heterogeneous and geographically distributed systems of computers, networks, and storage devices that collectively act as a single virtual computer. A key challenge...
We present aligned hierarchies, a novel solution to the dimension reduction problem, representing high-dimensional and noisy sequential data as a low-dimensional object that encodes relevant information. In this thesis, we motivate our presentation...
From deciding what to eat first or what stock to invest in, the order in which we prefer to experience events and the amount of risk we are willing to undertake are factors that influence our choices. However, the mechanisms underlying order and...
This thesis contains some results concerning groupoid dynamical systems and crossed products. We introduce the notion of a proper groupoid dynamical system and of its generalized fixed point algebra. We show that our notion of proper groupoid...
We start by introducing avoidance coupling of Markov chains, with an overview of existing results. We then introduce and motivate a new notion, uniform coupling. We show that the only Markovian avoidance coupling on a cycle is of this type, and...
In this thesis, we study the dynamics of magnetic flows on compact nilmanifolds. Magnetic flows are generalizations of geodesic flows. They model the motion of a particle of unit mass and unit charge in a smooth manifold M in the presence of a...
For a local field K, we study the affine buildings Ξ n and Δ n naturally associated to SL n ( K ) and Sp n ( K ), respectively. Since Sp n ( K ) is a subgroup of SL 2 n ( K ), we investigate properties of a natural embedding of Δ n in Ξ 2 n ....
Partially ordered sets. ; Convex polytopes. ; Representations of groups.
This thesis deals with geometric representations of ordered sets. In a geometric representation, each element of the ordered set is assigned a geometric object, with two elements incomparable in the ordered set if and only if the corresponding...
I consider the problem of extending certain invariants of subsets of natural numbers to their equivalents for subsets of larger cardinals. The two specific questions I will address are the extension of the off-branch number [Special characters...
The Border Gateway Protocol (BGP) facilitates communication between parts of the Internet by determining paths by which data can get from one network to any other. Just as IP is used ubiquitously as an addressing scheme, BGP is used ubiquitously...
For many scientific applications, the data set cannot entirely fit in main memory. The data must reside out-of-core, i.e., on parallel disks. For many basic data-movement operations such as permuting, if the programmer does not design efficient...