Title
Observability Properties of Colored Graphs
Abstract
A colored graph is a directed graph in which nodes or edges have been assigned colors that are not necessarily unique. Observability problems in such graphs consider whether an agent observing the colors of edges or nodes traversed on a path in the graph can determine which node they are at currently or which nodes were visited earlier in the traversal. Previous research efforts have identified several different notions of observability as well as the associated properties of graphs for which those observability properties hold. This paper unifies the prior work into a common framework with several new results about relationships between those notions and associated graph properties. The new framework provides an intuitive way to reason about the attainable accuracy as a function of lag and time spent observing, and identifies simple modifications to improve the observability of a given graph. We show that one form of the graph modification problem is in NP-Complete. The intuition of the new framework is borne out with numerical experiments. This work has implications for problems that can be described in terms of an agent traversing a colored graph, including the reconstruction of hidden states in a hidden Markov model (HMM).
Year
DOI
Venue
2020
10.1109/TNSE.2019.2948474
IEEE Transactions on Network Science and Engineering
Keywords
DocType
Volume
Graph theory,graph labeling,Markov processes,weak models,tracking
Journal
7
Issue
ISSN
Citations 
3
2327-4697
0
PageRank 
References 
Authors
0.34
0
5
Name
Order
Citations
PageRank
Chilenski Mark100.68
George Cybenko201.35
Isaac Dekine300.68
Piyush Kumar400.34
Gil Raz500.68