Supervisory Control of Timed Discrete-Event Systems Subject to Communication Delays and Non-FIFO Observations

Supervisory Control of Discrete-Event Systems under Attacks: An Overview and Outlook

“…For instance, let us consider that an event, say σ ∈ Σ o , is observed after a delay of one step (of the event occurrence), then in the delayed observed plant, σ is deleted at every state where it is enabled and inserted after the next transition. There are several papers investigating networked supervisory control of discrete-event systems with communication problems such as delays, losses and non-FIFO observations [31], [32]. To deal with network communication delays and losses, in [31], a mapping is introduced to model the plant under observation delay and losses.…”

“…Moreover, in [32], a non-FIFO observation channel is considered where events may be observed not necessarily in the same order as they have been executed in the plant. For instance, a word w = σ 1 σ 2 where σ 1 , σ 2 ∈ Σ o may be observed as σ 1 σ 2 or σ 2 σ 1 .…”

“…Non-FIFO observation has the same effect as a replacement attack in the sensor channel. In [32], a networked supervisor which is robust to communication delays and non-FIFO observations is synthesized through a new synthesis algorithm.…”

Supervisory Control of Discrete-Event Systems in an Asynchronous Setting

“…The drawback of the mentioned conditions is that they disqualify many relevant cases that do not satisfy the condition. More recently, a networked supervisory control framework has been introduced in [14] where a networked supervisor is synthesized to deal with communication delays. To indicate that enabling, execution, and observation of events do not occur at the same time, different notions for enabling and observed events are introduced.…”

“…Also, the observation of an event may occur immediately after execution in the plant or at some point in the future. Our asynchronous supervisory control setting is close to the networked supervisory control framework introduced in [14]. We use the same notations for enabling, execution, and observation of events as discussed in [14].…”