51 research outputs found

    Exactly solvable reaction diffusion models on a Cayley tree

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    The most general reaction-diffusion model on a Cayley tree with nearest-neighbor interactions is introduced, which can be solved exactly through the empty-interval method. The stationary solutions of such models, as well as their dynamics, are discussed. Concerning the dynamics, the spectrum of the evolution Hamiltonian is found and shown to be discrete, hence there is a finite relaxation time in the evolution of the system towards its stationary state.Comment: 9 pages, 2 figure

    TaLoS: secure and transparent TLS termination inside SGX enclaves

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    We introduce TaLoS1, a drop-in replacement for existing transport layer security (TLS) libraries that protects itself from a malicious environment by running inside an Intel SGX trusted execution environment. By minimising the amount of enclave transitions and reducing the overhead of the remaining enclave transitions, TaLoS imposes an overhead of no more than 31% in our evaluation with the Apache web server and the Squid proxy

    Glamdring: automatic application partitioning for Intel SGX

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    Trusted execution support in modern CPUs, as offered by Intel SGX enclaves , can protect applications in untrusted environments. While prior work has shown that legacy applications can run in their entirety inside enclaves, this results in a large trusted computing base (TCB). Instead, we explore an approach in which we partition an applica- tion and use an enclave to protect only security-sensitive data and functions, thus obtaining a smaller TCB. We describe Glamdring , the first source-level parti- tioning framework that secures applications written in C using Intel SGX. A developer first annotates security- sensitive application data. Glamdring then automatically partitions the application into untrusted and enclave parts: (i) to preserve data confidentiality, Glamdring uses dataflow analysis to identify functions that may be ex- posed to sensitive data; (ii) for data integrity, it uses back- ward slicing to identify functions that may affect sensitive data. Glamdring then places security-sensitive functions inside the enclave, and adds runtime checks and crypto- graphic operations at the enclave boundary to protect it from attack. Our evaluation of Glamdring with the Mem- cached store, the LibreSSL library, and the Digital Bitbox bitcoin wallet shows that it achieves small TCB sizes and has acceptable performance overheads

    An information-theoretic Phase I/II design for molecularly targeted agents that does not require an assumption of monotonicity

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    For many years phase I and phase II clinical trials have been conducted separately, but there has been a recent shift to combine these phases. Although a variety of phase I–II model‐based designs for cytotoxic agents have been proposed in the literature, methods for molecularly targeted agents (TAs) are just starting to develop. The main challenge of the TA setting is the unknown dose–efficacy relationship that can have either an increasing, plateau or umbrella shape. To capture these, approaches with more parameters are needed or, alternatively, more orderings are required to account for the uncertainty in the dose–efficacy relationship. As a result, designs for more complex clinical trials, e.g. trials looking at schedules of a combination treatment involving TAs, have not been extensively studied yet. We propose a novel regimen finding design which is based on a derived efficacy–toxicity trade‐off function. Because of its special properties, an accurate regimen selection can be achieved without any parametric or monotonicity assumptions. We illustrate how this design can be applied in the context of a complex combination–schedule clinical trial. We discuss practical and ethical issues such as coherence, delayed and missing efficacy responses, safety and futility constraints

    Enabling Data Sharing in Contextual Environments

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    Internet of Things environments enable us to capture more and more data about the physical environment we live in and about ourselves. The data enable us to optimise resources, personalise services and offer unprecedented insights into our lives. However, to achieve these insights data need to be shared (and sometimes sold) between organisations imposing rights and obligations upon the sharing parties and in accordance with multiple layers of sometimes conflicting legislation at international, national and organisational levels. In this work, we show how such rules can be captured in a formal representation called "Data Sharing Agreements". We introduce the use of abductive reasoning and argumentation based techniques to work with context dependent rules, detect inconsistencies between them, and resolve the inconsistencies by assigning priorities to the rules. We show how through the use of argumentation based techniques use-cases taken from real life application are handled flexibly addressing trade-offs between confidentiality, privacy, availability and safety

    Validating judgments of perspective embedding:Further explorations of a new tool for literary analysis

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    Previous work ( Whalen, Zunshine, & Holquist, 2012 ) has shown that perspective embedding ("she thought I left" embedding her perspective on "I left") affects reading times for short vignettes. With increasing levels of embedment 1–5, reading times rose almost linearly. Level 0 was as slow as 3–4. Embedment level was determined by the authors, but validation by others is desirable. In Experiment 1, we trained 12 literature students to make embedment judgments. Their judgments correlated highly with ours (.94 on average) and agreed exactly in the majority of cases (74.5%); almost all were within one (94.2%). In Experiment 2, judgments of the first three paragraphs of "To Kill a Mockingbird" ( Lee, 1960 ) yielded a lower level of agreement; literature uses subtle means for introducing perspective embedment, and individuals differ about including them. Assessment of perspective embedding, and exploration of sources of disagreements, provide new tools for analyzing literature
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