18,065 research outputs found
Hybrid Information Flow Analysis for Programs with Arrays
Information flow analysis checks whether certain pieces of (confidential)
data may affect the results of computations in unwanted ways and thus leak
information. Dynamic information flow analysis adds instrumentation code to the
target software to track flows at run time and raise alarms if a flow policy is
violated; hybrid analyses combine this with preliminary static analysis.
Using a subset of C as the target language, we extend previous work on hybrid
information flow analysis that handled pointers to scalars. Our extended
formulation handles arrays, pointers to array elements, and pointer arithmetic.
Information flow through arrays of pointers is tracked precisely while arrays
of non-pointer types are summarized efficiently.
A prototype of our approach is implemented using the Frama-C program analysis
and transformation framework. Work on a full machine-checked proof of the
correctness of our approach using Isabelle/HOL is well underway; we present the
existing parts and sketch the rest of the correctness argument.Comment: In Proceedings VPT 2016, arXiv:1607.0183
Directed Security Policies: A Stateful Network Implementation
Large systems are commonly internetworked. A security policy describes the
communication relationship between the networked entities. The security policy
defines rules, for example that A can connect to B, which results in a directed
graph. However, this policy is often implemented in the network, for example by
firewalls, such that A can establish a connection to B and all packets
belonging to established connections are allowed. This stateful implementation
is usually required for the network's functionality, but it introduces the
backflow from B to A, which might contradict the security policy. We derive
compliance criteria for a policy and its stateful implementation. In
particular, we provide a criterion to verify the lack of side effects in linear
time. Algorithms to automatically construct a stateful implementation of
security policy rules are presented, which narrows the gap between
formalization and real-world implementation. The solution scales to large
networks, which is confirmed by a large real-world case study. Its correctness
is guaranteed by the Isabelle/HOL theorem prover.Comment: In Proceedings ESSS 2014, arXiv:1405.055
The Brownian motion as the limit of a deterministic system of hard-spheres
We provide a rigorous derivation of the brownian motion as the limit of a
deterministic system of hard-spheres as the number of particles goes to
infinity and their diameter simultaneously goes to , in the
fast relaxation limit (with a suitable
diffusive scaling of the observation time). As suggested by Hilbert in his
sixth problem, we rely on a kinetic formulation as an intermediate level of
description between the microscopic and the fluid descriptions: we use indeed
the linear Boltzmann equation to describe one tagged particle in a gas close to
global equilibrium. Our proof is based on the fundamental ideas of Lanford. The
main novelty here is the detailed study of the branching process, leading to
explicit estimates on pathological collision trees
The Translocal Event and the Polyrhythmic Diagram
This thesis identifies and analyses the key creative protocols in translocal performance practice, and ends with suggestions for new forms of transversal live and mediated
performance practice, informed by theory. It argues that ontologies of emergence in dynamic systems nourish contemporary practice in the digital arts. Feedback
in self-organised, recursive systems and organisms elicit change, and change transforms. The arguments trace concepts from chaos and complexity theory to virtual multiplicity, relationality, intuition and individuation (in the work of Bergson, Deleuze, Guattari, Simondon, Massumi, and other process theorists). It then examines the intersection of methodologies in philosophy, science and art and the
radical contingencies implicit in the technicity of real-time, collaborative composition. Simultaneous forces or tendencies such as perception/memory, content/
expression and instinct/intellect produce composites (experience, meaning, and intuition- respectively) that affect the sensation of interplay. The translocal
event is itself a diagram - an interstice between the forces of the local and the global, between the tendencies of the individual and the collective. The translocal is
a point of reference for exploring the distribution of affect, parameters of control and emergent aesthetics. Translocal interplay, enabled by digital technologies and network protocols, is ontogenetic and autopoietic; diagrammatic and synaesthetic; intuitive and transductive. KeyWorx is a software application developed for realtime, distributed, multimodal media processing. As a technological tool created by artists, KeyWorx supports this intuitive type of creative experience: a real-time, translocal âjammingâ that transduces the lived experience of a âbiogram,â a synaesthetic hinge-dimension. The emerging aesthetics are processual â intuitive, diagrammatic and transversal
Direct speech, subjectivity and speaker positioning in London English and Paris French
This paper examines functional similarities and differences in the use of pragmatic features â in particular quotatives and general extenders â on the right and left periphery of direct quotations. This comparative study, based on the analysis of a contemporary corpus of London English and Paris French (MLE â MPF) , finds that the form and frequency of these particles tend to vary not only with respect to social factors such as speakersâ age and gender, but also with respect to the different pragmatic functions they come to perform in different interactional settings. The contemporary data is analysed both qualitatively and quantitatively to show how different variants position the speaker in relation to: i) the content of the quote, ii) the interlocutors, iii) the presumed author of the quote. The paper aims to contribute to a better understanding of pragmatic universals and variability in the use of direct speech
Employing geographical principles for sampling in state of the art dialectological projects
The aims of this paper are twofold: First, we locate the most effective human geographical methods for sampling across space in large-scale dialectological projects. We propose two geographical concepts as a basis for sampling decisions: Geo-demographic classification, which is a multidimensional method used for the socio-economic grouping of areas. We also develop an updated version of functional regions that can be used in sociolinguistic research. We then report on the results of a pilot project that applies these models to collect data regarding the acceptability of vernacular morpho-syntactic forms in the North-East of England. Following the method of natural breaks advocated for dialectology by Horvath and Horvath (2002), we interpret breaks in the probabilistic patterns as areas of dialect transitions. This study contributes to the debate about the role and limitations of spatiality in linguistic analysis. It intends to broaden our knowledge about the interfaces between human geography and dialectology
- âŠ