Observability of Boolean control networks: A unified approach based on the theories of finite automata

TL;DR

This paper introduces a unified automaton-based method to determine all four types of observability in Boolean control networks, resolving a five-year open problem and clarifying the nonlinearity aspects of BCNs.

Contribution

A novel approach using weighted pair graphs and finite automata to unify the analysis of all observability types in BCNs.

Findings

All four types of observability are distinguishable and none are equivalent.

The approach effectively determines observability relying on initial states and inputs.

Reveals the inherent nonlinearity in BCNs through non-equivalence of observability types.

Abstract

The problem on how to determine the observability of Boolean control networks (BCNs) has been open for five years already. In this paper, we propose a unified approach to determine all the four types of observability of BCNs in the literature. We define the concept of weighted pair graphs for BCNs. In the sense of each observability, we use the so-called weighted pair graph to transform a BCN to a finite automaton, and then we use the automaton to determine observability. In particular, the two types of observability that rely on initial states and inputs in the literature are determined. Finally, we show that no pairs of the four types of observability are equivalent, which reveals the essence of nonlinearity of BCNs.