Ivano Salvo

M3 mobility types for mobile processes in mobile ambients

Abstract We present an ambient-like calculus in which the open capability is dropped, and a new form of “lightweight” process mobility is introduced. The calculus comes equipped with a type system that allows the kind of values exchanged in communications and the access and mobility properties of processes to be controlled. A type inference procedure determines the “minimal” requirements to accept a system or a component as well typed. This gives a kind of principal typing. As an expressiveness test, we show that some well known calculi of concurrency and mobility can be encoded in our calculus in a natural way.

Security Types for Mobile Safe Ambients

The Ambient Calculus and the Safe Ambient Calculus have been recently successfully proposed as models for the Web. They are based on the notions of ambient movement and ambient opening. Different type disciplines have been devised for them in order to avoid unwanted behaviours of processes. In the present paper we propose a type discipline for safe mobile ambients which is essentially motivated by ensuring security properties. We associate security levels to ambients and we require that an ambient at security level s can only be traversed or opened by ambients at security level at least s. Since the movement and opening rights can be unrelated, we consider two partial orders between security levels. We also discuss some meaningful examples of use of our type discipline.

Model-based synthesis of control software from system-level formal specifications

Many embedded systems are indeed software-based control systems, that is, control systems whose controller consists of control software running on a microcontroller device. This motivates investigation on formal model-based design approaches for automatic synthesis of embedded systems control software. We present an algorithm, along with a tool QKS implementing it, that from a formal model (as a discrete-time linear hybrid system) of the controlled system (plant), implementation specifications (that is, number of bits in the Analog-to-Digital, AD, conversion) and system-level formal specifications (that is, safety and liveness requirements for the closed loop system) returns correct-by-construction control software that has a Worst-Case Execution Time (WCET) linear in the number of AD bits and meets the given specifications. We show feasibility of our approach by presenting experimental results on using it to synthesize control software for a buck DC-DC converter, a widely used mixed-mode analog circuit, and for the inverted pendulum.

Automatic control software synthesis for quantized discrete time hybrid systems

Many Embedded Systems are indeed Software Based Control Systems, that is control systems whose controller consists of control software running on a microcontroller device. This motivates investigation on Formal Model Based Design approaches for automatic synthesis of embedded systems control software. This paper addresses control software synthesis for discrete time nonlinear hybrid systems. We present a methodology to overapproximate the dynamics of a discrete time nonlinear hybrid system ℌ by means of a discrete time linear hybrid system Lℌ, in such a way that controllers for Lℌ are guaranteed to be controllers for ℌ. We present experimental results on control software synthesis for the inverted pendulum, a challenging and meaningful control problem.

Synthesis of quantized feedback control software for discrete time linear hybrid systems

We present an algorithm that given a Discrete Time Linear Hybrid System

Undecidability of quantized state feedback control for discrete time linear hybrid systems

{\cal H}

On model based synthesis of embedded control software

returns a correct-by-construction software implementation K for a (near time optimal) robust quantized feedback controller for

Demand-aware price policy synthesis and verification services for Smart Grids

{\cal H}

On-the-Fly Control Software Synthesis

along with the set of states on which K is guaranteed to work correctly (controllable region) Furthermore, K has a Worst Case Execution Time linear in the number of bits of the quantization schema.

A type inference algorithm for secure Ambients

We show that the existence of a quantized controller for a given Discrete Time Linear Hybrid System (DTLHS) is undecidable. This is a relevant class of controllers since control software always implements a quantized controller. Furthermore, we investigate the relationship between dense time modelling and discrete time modelling by showing that any Rectangular Hybrid Automaton (and thus, any Timed Automaton) can be modelled as a DTLHS.