4,702 research outputs found
Validating a Web Service Security Abstraction by Typing
An XML web service is, to a first approximation, an RPC service in which
requests and responses are encoded in XML as SOAP envelopes, and transported
over HTTP. We consider the problem of authenticating requests and responses at
the SOAP-level, rather than relying on transport-level security. We propose a
security abstraction, inspired by earlier work on secure RPC, in which the
methods exported by a web service are annotated with one of three security
levels: none, authenticated, or both authenticated and encrypted. We model our
abstraction as an object calculus with primitives for defining and calling web
services. We describe the semantics of our object calculus by translating to a
lower-level language with primitives for message passing and cryptography. To
validate our semantics, we embed correspondence assertions that specify the
correct authentication of requests and responses. By appeal to the type theory
for cryptographic protocols of Gordon and Jeffrey's Cryptyc, we verify the
correspondence assertions simply by typing. Finally, we describe an
implementation of our semantics via custom SOAP headers.Comment: 44 pages. A preliminary version appears in the Proceedings of the
Workshop on XML Security 2002, pp. 18-29, November 200
Bisimilarity as a Theory of Functional Programming
AbstractMorris-style contextual equivalence — invariance of termination under any context of ground type — is the usual notion of operational equivalence for deterministic functional languages such as FPC (PCF plus sums, products and recursive types). Contextual equivalence is hard to establish directly. Instead we define a labelled transition system for call-by-name FPC (and variants) and prove that CCS-style bisimilarity equals contextual equivalence — a form of operational extensionality. Using co-induction we establish equational laws for FPC. By considering variations of Milner's ‘bisimulations up to ∼’ we obtain a second co-inductive characterisation of contextual equivalence in terms of reduction behaviour and production of values. Hence we use co-inductive proofs to establish contextual equivalence in a series of stream-processing examples. Finally, we consider a form of Milner's original context lemma for FPC, but conclude that our form of bisimilarity supports simpler co-inductive proofs
The Long Non-coding RNA Malat1 Regulates Inflammatory Cytokine Production in Chronic Diabetic Complications
We examined the role of MALAT1, a highly conserved nuclear lncRNA, in chronic diabetic complications affecting the heart and kidneys, specifically with respect to inflammatory cytokine production. Endothelial cells, exposed to various glucose levels, and MALAT1 knockout mice and controls, with or without streptozotocin-induced diabetes were examined. Endothelial cells cultured with high glucose, and renal and cardiac tissue from diabetic mice showed increased inflammatory cytokine (eg. IL-6, IL1β, TNFα) production along with transient MALAT1 upregulation. This was confirmed by both transcript and protein analyses, and such changes were prevented in the MALAT1 knockout diabetic animals. In the malat1 knockout animals, diabetes-induced cardiac dysfunction was also prevented. We further identified that such actions of MALAT1 are mediated by specific downstream molecules including SAA3 and p53. The data from this study provided direct evidence to the importance of MALAT1 in the pathogenesis of chronic diabetic complications involving the heart and kidneys
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Where's the harm? A social marketing approach to reframing 'problem' drinking cultures
Alcohol consumption is often linked to a broad range of social and health problems, yet alcohol also plays a fundamental role in social bonding between people. This paper considers the potential of social marketing to contribute to alcohol consumption reduction and reframe social norms that encourage 'problem' drinking. Based on qualitative research with a variety of Scottish drinkers, the paper emphasises how and why a better understanding of the culturally bound meanings of alcohol (e.g. social identity, self-concept) are of crucial importance to inform any social marketing approach to reframing excessive drinking
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