Let {X(t);t ≥ 0} be a continuous-time branching-immigration system with branching rates {bk; k ≥ 0,k≠ 1} and immigration rates {ak; k ≥ 1}. We assume that b0 = 0, \(m=:{\sum }_{k=1}^{\infty }kb_{k}<\infty \) and \(a=:{\sum }_{k=1}^{\infty }ka_{k}<\infty \). In this paper, we first discuss the martingale property of W(t) = e−mtX(t) − m− 1a(1 − e−mt) and prove that it has a limit W. Furthermore, we show

Systems prone to faults are often equipped with a controller whose aim consists in restricting the behaviour of the system in order to perform a diagnosis. Such a task is called active diagnosis. However to avoid that the controller degrades the system in view of diagnosis, a second objective in terms of quality of service is usually assigned to the controller. In the framework of stochastic systems

The aim of this paper is the generation of the min-critical and max-critical subsystems which determine the optimal cycle times. Considering a Time Interval Model which can describe Timed Event Graphs and P-time Event Graphs completely, each critical subsystem depends on the lower and upper bounds of the time durations. The proposed approach which is based on linear programming makes a classification

Timed Event Graphs (TEGs) are a graphical model for decision free and time-invariant Discrete Event Systems (DESs). To express systems with time-variant behaviors, a new form of synchronization, called partial synchronization (PS), has been introduced for TEGs. Unlike exact synchronization, where two transitions t1,t2 can only fire if both transitions are simultaneously enabled, PS of transition t1

It has been shown that, under some service policies, a queueing network can be unstable even if the load of every station is less than one. Although the stability of queueing systems in some special cases (e.g. under First-Buffer-First-Served policy) has been well addressed, there are still difficulties in coping with more general networks. In this paper, we study the stability problem through depicting

In this paper, we formalize and solve a state-based Supervisory Control problem with restrictions on the supervisor realization that have not been tackled by the Supervisory Control Theory (SCT) community so far. This problem was derived from the application of SCT to intervene in the dynamics of gene regulatory networks, a relevant problem in the fields of Systems and Synthetic Biology. In our framework

The original version of this article unfortunately contained a mistake the last two lines in Table 1 of ‘Appendix H’ should be moved to the next page of the table.

The development, in the last decades, of technologies for precision agriculture allows the acquisition of crop data with a high spatial resolution. This offers possibilities for innovative control and raises new logistics issues that may be solved using discrete event models. In vineyards, some technologies make it possible to define zones with different qualities of grapes and sort the grapes at harvest

In this paper, we shall formulate and address a problem of covert actuator attacker synthesis for cyber-physical systems that are modeled by discrete-event systems. We assume the actuator attacker partially observes the execution of the closed-loop system and is able to modify each control command issued by the supervisor on a specified attackable subset of controllable events. We provide straightforward

In this paper we discuss scheduling of semi-cyclic discrete-event systems, for which the set of operations may vary over a limited set of possible sequences of operations. We introduce a unified modeling framework in which different types of semi-cyclic discrete-event systems can be described by switching max-plus linear (SMPL) models. We use a dynamic graph to visualize the evolution of an SMPL system

A common approach to controller synthesis for hybrid systems is to first establish a discrete-event abstraction and then to use methods from supervisory control theory to synthesise a controller. In this paper, we consider behavioural abstractions of hybrid systems with a prescribed discrete-event input/output interface. We discuss a family of abstractions based on so called experiments which consist

Designing supervisory controllers for high-tech systems is becoming increasingly complex due to demands for verified safety, higher quality and availability, and extending functionality. Supervisor synthesis is a method to automatically derive a supervisor from a model of the plant and a model of the control requirements. While supervisor synthesis is an active research topic, only a few reports exist

This paper presents an algorithm that combines modular synthesis for extended finite-state machines (EFSM) with abstraction of variables by symbolic manipulation, in order to compute least restrictive controllable supervisors. Given a modular EFSM system consisting of several components, the proposed algorithm synthesises a separate supervisor for each specification component. To synthesise each supervisor

Detectability is a basic property of dynamic systems: when it holds an observer can use the current and past values of the observed output signal produced by a system to reconstruct its current state. In this paper, we consider properties of this type in the framework of discrete-event systems modeled by labeled Petri nets and finite automata. We first study weak approximate detectability. This property

It has been shown that annotating Petri nets unfoldings with time stamps allows to build distributed testers for distributed systems. However, the construction of the annotated unfolding of a distributed system currently remains a centralized task. In this paper we extend a distributed unfolding technique in order to annotate the resulting unfolding with time stamps. This allows distributed construction

We study decentralized diagnosis whose objective is fault detection in discrete event systems using decentralized architectures. We first identify a basic diagnosis and two virtual diagnoses as the simplest language-based decentralized diagnosis architectures. The virtual diagnoses cannot be used alone, they are provided to be combined with other diagnoses. On the other side, inference-based diagnosis

Various aspects of privacy and safety in many application domains can be assessed based on proper analysis of successive measurements that are collected about a given system. This work is devoted to such issues in the context of timed stochastic discrete event systems (DES) that are modeled with partially observed timed stochastic Petri net models. The first contribution is to introduce a k-step trajectory-observer

Real-world PLC software is modular and composed of many different function blocks. Nevertheless, common approaches to PLC software verification do not leverage this but resort to inlining, or analyse instances of the same function block type independently. With the advent of constrained Horn clauses as the basis for automated program verification, many state-of-the-art verification procedures build

The objective of this paper is to provide a concise introduction to the max-plus algebra and to max-plus linear discrete-event systems. We present the basic concepts of the max-plus algebra and explain how it can be used to model a specific class of discrete-event systems with synchronization but no concurrency. Such systems are called max-plus linear discrete-event systems because they can be described

Reactive synthesis and supervisory control theory both provide a design methodology for the automatic and algorithmic design of digital systems from declarative specifications. The reactive synthesis approach originates in computer science, and seeks to synthesise a system that interacts with its environment over time and that, doing so, satisfies a prescribed specification. Here, the distinguishing

It is a well known fact that not all max-plus automata can be determinized, i.e. transformed into deterministic max-plus automata with the same behavior. A classical sequentialization procedure, extended in the literature to max-plus automata, succeeds in computing an equivalent deterministic max-plus automaton for important subclasses of max-plus automata. This procedure is based on the normalization

This research proposes an automatic strategy for planning a team of identical robots evolving in a known environment. The robots should satisfy a global task for the whole team, given in terms of a Linear Temporal Logic (LTL) formula over predefined regions of interest. A Robot Motion Petri Net (RMPN) system is used for modeling the evolution of the robotic team in the environment, bringing the advantage

We extend Stochastic Flow Models (SFMs), used for a large class of discrete event and hybrid systems, by including the delays which typically arise in flow movements, as well as blocking effects due to space constraints. We apply this framework to the multi-intersection traffic light control problem by including transit delays for vehicles moving from one intersection to the next and possible blocking

This paper describes algorithms to compute a counterexample when compositional nonblocking verification determines that a discrete event system is blocking. Counterexamples are an important feature of model checking that explains the cause of a detected problem, greatly helping users to understand and fix faults. In compositional verification, counterexamples are difficult to compute due to the large

Timed Event Graphs (TEGs) can be described by time invariant (max,+) linear systems. This formalism has been studied for modelling, analysis and control synthesis for decision-free timed Discrete Event Systems (DESs), for instance specific manufacturing processes or transportation networks operating under a given logical schedule. However, many applications exhibit time-variant behaviour, which cannot

This work is concerned with the computation of problematic configurations and problematic choice-join pairs in timed continuous Petri nets under the infinite server semantics; those net structural objects explain possible bad/counter-intuitive behaviors of systems, such as non-monotonicities and discontinuities of the equilibrium throughput. The calculation of problematic configurations is a computationally

The greedy strategy is an approximation algorithm to solve optimization problems arising in decision making with multiple actions. How good is the greedy strategy compared to the optimal solution? In this survey, we mainly consider two classes of optimization problems where the objective function is submodular. The first is set submodular optimization, which is to choose a set of actions to optimize

Opacity is an important property in control of information flow among networked agents. In this paper, we investigate information control problems in networked discrete event systems using opacity. In a networked discrete event system, communication among agents is via a shared communication network. Since delays and losses are unavoidable in networked discrete event systems, they must be considered

The paper mentioned in the title proposed a new definition of increasing repetitive input sequences for synchronized Petri nets and stated that it can be used to construct a finite modified coverability graph for any unbounded SynPN. In this note, we discuss the notion of unboundedness for SynPNs and show via an example that actually the modified coverability graph may be infinite due the presence

Monoid actions of trace monoids over finite sets are powerful models of concurrent systems—for instance they encompass the class of 1-safe Petri nets. We characterise Markov measures attached to concurrent systems by finitely many parameters with suitable normalisation conditions. These conditions involve polynomials related to the combinatorics of the monoid and of the monoid action. These parameters

This paper considers the finite-horizon risk-sensitive optimality for continuous-time Markov decision processes, and focuses on the more general case that the transition rates are unbounded, cost/reward rates are allowed to be unbounded from below and from above, the policies can be history-dependent, and the state and action spaces are Borel ones. Under mild conditions imposed on the decision process’s