Gerardo Schneider

A formal language for electronic contracts

In this paper we propose a formal language for writing electronic contracts, based on the deontic notions of obligation, permission, and prohibition. We take an ought-to-do approach, where deontic operators are applied to actions instead of state-of-affairs. We propose an extension of the µ-calculus in order to capture the intuitive meaning of the deontic notions and to express concurrent actions. We provide a translation of the contract language into the logic, the semantics of which faithfully captures the meaning of obligation, permission and prohibition. We also show how our language captures most of the intuitive desirable properties of electronic contracts, as well as how it avoids most of the classical paradoxes of deontic logic. We finally show its applicability on a contract example.

LARVA --- Safer Monitoring of Real-Time Java Programs (Tool Paper)

The use of runtime verification, as a lightweight approach to guarantee properties of systems, has been increasingly employed on real-life software. In this paper, we present the tool LARVA, for the runtime verification of properties of Java programs, including real-time properties. Properties can be expressed in a number of notations, including timed-automata enriched with stopwatches, Lustre, and a subset of the duration calculus. The tool has been successfully used on a number of case-studies, including an industrial system handling financial transactions. LARVA also performs analysis of real-time properties, to calculate, if possible, an upper-bound on the memory and temporal overheads induced by monitoring. Moreover, through property analysis, LARVA assesses the impact of slowing down the system through monitoring, on the satisfaction of the properties.

Dynamic Event-Based Runtime Monitoring of Real-Time and Contextual Properties

Given the intractability of exhaustively verifying software, the use of runtime-verification, to verify single execution paths at runtime, is becoming popular. Although the use of runtime verification is increasing in industrial settings, various challenges still are to be faced to enable it to spread further. We present dynamic communicating automata with timers and events to describe properties of systems, implemented in Larva, an event-based runtime verification tool for monitoring temporal and contextual properties of Java programs. The combination of timers with dynamic automata enables the straightforward expression of various properties, including replication of properties, as illustrated in the use of Larva for the runtime monitoring of a real life case study -- an online transaction system for credit card. The features of Larva are also benchmarked and compared to a number of other runtime verification tools, to assess their respective strengths in property expressivity and overheads induced through monitoring.

Run-Time Monitoring of Electronic Contracts

Electronic inter-organizational relationships are governed by contracts regulating their interaction, therefore it is necessary to run-time monitor the contracts, as to guarantee their fulfillment. The present work shows how to obtain a run-time monitor for contracts written in

Differential Privacy: Now it's Getting Personal

\mathcal {CL}

Automatic Conflict Detection on Contracts

, a formal specification language which allows to write conditional obligations, permissions, and prohibitions over actions. The trace semantics of

A dynamic deontic logic for complex contracts

\mathcal {CL}

CLAN: A Tool for Contract Analysis and Conflict Discovery

formalizes the notion of a trace fulfills a contract. We show how to obtain, for a given contract, an alternating Buchi automaton which accepts exactly the traces that fulfill the contract. This automaton is the basis for obtaining a finite state machine which acts as a run-time monitor for

Model checking contracts: a case study

\mathcal {CL}

Towards Computing Phase Portraits of Polygonal Differential Inclusions

contracts.