1,248 research outputs found
Expressiveness of Generic Process Shape Types
Shape types are a general concept of process types which work for many
process calculi. We extend the previously published Poly* system of shape types
to support name restriction. We evaluate the expressiveness of the extended
system by showing that shape types are more expressive than an implicitly typed
pi-calculus and an explicitly typed Mobile Ambients. We demonstrate that the
extended system makes it easier to enjoy advantages of shape types which
include polymorphism, principal typings, and a type inference implementation.Comment: Submitted to Trustworthy Global Computing (TGC) 2010
A Type Inference Algorithm for Secure Ambients
We consider a type discipline for the Ambient Calculus that associates ambients with security levels and constrains them to be traversed by or opened in ambients of higher security clearance only. We present a bottom-up algorithm that, given an untyped process , computes a minimal set of constraints on security levels such that all actions during runs of are performed without violating the security level priorities. Such an algorithm appears to be a prerequisite to use type systems to ensure security properties in the web scenario
Secrecy in Untrusted Networks
We investigate the protection of migrating agents against the untrusted sites they traverse. The resulting calculus provides a formal framework to reason about protection policies and security protocols over distributed, mobile infrastructures, and aims to stand to ambients as the spi calculus stands to ?. We present a type system that separates trusted and untrusted data and code, while allowing safe interactions with untrusted sites. We prove that the type system enforces a privacy property, and show the expressiveness of the calculus via examples and an encoding of the spi calculus
Mutual Mobile Membranes with Timers
A feature of current membrane systems is the fact that objects and membranes
are persistent. However, this is not true in the real world. In fact, cells and
intracellular proteins have a well-defined lifetime. Inspired from these
biological facts, we define a model of systems of mobile membranes in which
each membrane and each object has a timer representing their lifetime. We show
that systems of mutual mobile membranes with and without timers have the same
computational power. An encoding of timed safe mobile ambients into systems of
mutual mobile membranes with timers offers a relationship between two
formalisms used in describing biological systems
Space-Aware Ambients and Processes
Resource control has attracted increasing interest in foundational research on distributed systems. This paper focuses on space control and develops an analysis of space usage in the context of an ambient-like calculus with bounded capacities and weighed processes, where migration and activation require space. A type system complements the dynamics of the calculus by providing static guarantees that the intended capacity bounds are preserved throughout the computation
A Calculus of Bounded Capacities
Resource control has attracted increasing interest in foundational research on distributed systems. This paper focuses on space control and develops an analysis of space usage in the context of an ambient-like calculus with bounded capacities and weighed processes, where migration and activation require space. A type system complements the dynamics of the calculus by providing static guarantees that the intended capacity bounds are preserved throughout the computation
Types for BioAmbients
The BioAmbients calculus is a process algebra suitable for representing
compartmentalization, molecular localization and movements between
compartments. In this paper we enrich this calculus with a static type system
classifying each ambient with group types specifying the kind of compartments
in which the ambient can stay. The type system ensures that, in a well-typed
process, ambients cannot be nested in a way that violates the type hierarchy.
Exploiting the information given by the group types, we also extend the
operational semantics of BioAmbients with rules signalling errors that may
derive from undesired ambients' moves (i.e. merging incompatible tissues).
Thus, the signal of errors can help the modeller to detect and locate unwanted
situations that may arise in a biological system, and give practical hints on
how to avoid the undesired behaviour
Communication Interference in Mobile Boxed Ambients (talk)
Talk given at FST&TCS 200
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