State-Labeled Safety Analysis of Modular Observers for Opacity Verification

A survey of the opacity of discrete event systems

“…In 2014, Sabouri et al [10] studied the verification of the current state opacity, and carried out quantitative analysis of the current state opacity attributes.It was the first time that the system opacity was quantitatively studied with probability. In 2022, Lennarsson [17] used modular modeling to verify the current state opacity of a complex system with a large number of observer states, and greatly reduced the verification time. The verification time of the system with an observer state is about 1 second.…”

“…The researchers make the system meet the characteristics of strong opacity,weak opacity and complete transparency by modifying the language set [9] . Not only for classic DES,the more complex opacity properties of probability DES [10][11][12] random DES [13][14][15] have been studied in depth.At the same time,the more complex modular system [16,17] has also been studied.These more complex systems are more suitable for practical industrial production applications.For checking whether the system has opacity properties, the verification method is generally adopted [18][19][20] . At present,there have been in-depth studies on various types of opacity verification algorithms and complexity,such as step opacity [21,22] infinite step opacity [23] , initial state opacity [24] , etc.There are currently two methods to make systems without opacity attribute have opacity attribute.One is the method based on the theory of supervision and control [25][26][27] , and the other is the enforcement method [28,29] .…”