Corin Pitcher

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Multiple firewalls typically cooperate to provide security properties for a network, despite the fact that these firewalls are often spatially distributed and configured in isolation. Without a global view of the network configuration, such a system is ripe for misconfiguration, causing conflicts and major security vulnerabilities. We propose <i>FLIP</i>,(More)
Randomization is used in computer security as a tool to introduce unpredictability into the software infrastructure. In this paper, we study the use of randomization to achieve the secrecy and integrity guarantees for local memory. We follow the approach set out by Abadi and Plot kin. We consider the execution of an idealized language in two environments.(More)
Cluster of differentiation antigen 4 (CD4), the T lymphocyte antigen receptor component and human immunodeficiency virus coreceptor, is down-modulated when cells are activated by antigen or phorbol esters. During down-modulation CD4 dissociates from p56(lck), undergoes endocytosis through clathrin-coated pits, and is then sorted in early endosomes to late(More)
CD4 is a transmembrane glycoprotein of the immunoglobulin superfamily, expressed on developing thymocytes, major histocompatibility class II (class II MHC) restricted mature T lymphocytes and, in humans, on cells of the macrophage/monocyte lineage. On lymphoid cells, CD4 plays a critical role during thymocyte ontogeny and in the function of mature T cells.(More)
Non-deterministic programs can represent specifications, and non-determinism arises naturally in concurrent programming languages. In this dissertation, λ-calculi exhibiting erratic nondeterminism are studied in order to identify definitions and techniques that may be applicable to higher-order programming languages for specification or concurrency. The(More)
Cross-field particle transport in the scrape-off layer (SOL) of Alcator C-Mod [Phys. Plasmas 1, 1511 (1994)] can be characterized by an effective particle diffusivity (Deff) that increases markedly with distance from the separatrix. As a consequence, recycling onto the mainchamber walls is large compared to plasma flows into the divertor volume. The SOL(More)
Accountability mechanisms, which rely on after-the-fact verification, are an attractive means to enforce authorization policies. In this paper, we describe an operational model of accountability-based distributed systems. We describe analyses which support both the design of accountability systems and the validation of auditors for finitary accountability(More)