Matthieu Roy

Condition-Based Protocols for Set Agreement Problems

A condition C is a set of input vectors to a problem. A class of conditions that allow to solve k-set agreement in spite of f crashes in an asynchronous system is identified. A k-set agreement protocol that is always safe is described: it is guaranteed to terminate when the input vector belongs to C and it always decides on at most k different values, even if the input vector does not belong to C. While there are simple solutions when f < k, it is known that the k-set agreement problem has no solution when f ? k. Thus, the paper identifies classes of conditions that allow to solve this problem even when f ? k. The paper gives evidence that these are the only conditions that allow to solve set agreement, by proving the wait-free case. Two natural concrete conditions that belong to such a class are described. Finally, a more efficient k-set agreement protocol with only linear complexity (does not use snapshots), for any C that allows to solve consensus, when k ? f/(n - f) + 1 is presented. This shows how to trade fault-tolerance for agreement precision using the condition based approach.

Condition-based consensus solvability: a hierarchy of conditions and efficient protocols

Abstract.The condition-based approach for consensus solvability consists of identifying sets of input vectors, called conditions, for which there exists an asynchronous protocol solving consensus despite the occurrence of up to f process crashes. This paper investigates

A hierarchy of conditions for consensus solvability

\mathcal{C}_f

Distributed run-time WCET controller for concurrent critical tasks in mixed-critical systems

, the largest set of conditions which allow us to solve the consensus problem in an asynchronous shared memory system.The first part of the paper shows that

Geo-registers: An Abstraction for Spatial-Based Distributed Computing

\mathcal{C}_f

Run-Time Control to Increase Task Parallelism In Mixed-Critical Systems

is made up of a hierarchy of classes of conditions,

Architecting resilient computing systems: overall approach and open issues

\mathcal{C}^{[d]}_f

PROPS: A PRivacy-Preserving Location Proof System

where d is a parameter (called degree of the condition), starting with

Fault Injection in the Automotive Standard ISO 26262: An Initial Approach

d = \min(n-f,\allowbreak f)

Safety Trigger Conditions for Critical Autonomous Systems

and ending with d = 0, where