Libero Nigro

Followers

Following

Public Views

Uploads

Papers by Libero Nigro

Formal Modeling and Verification of Embedded Real-Time Systems: An Approach and Practical Tool Based on Constraint Time Petri Nets

Modeling and verification of the correct behavior of embedded real-time systems with strict timin... more Modeling and verification of the correct behavior of embedded real-time systems with strict timing constraints is a well-known and important problem. Failing to fulfill a deadline in system operation can have severe consequences in the practical case. This paper proposes an approach to formal modeling and schedulability analysis. A novel extension of Petri Nets named Constraint Time Petri Nets (C-TPN) is developed, which enables the modeling of a collection of interdependent realtime tasks whose execution is constrained by the use of priority and shared resources like processors and memory data. A C-TPN model is reduced to a network of Timed Automata in the context of the popular Uppaal toolbox. Both functional and, most importantly, temporal properties can be assessed by exhaustive model checking and/or statistical model checking based on simulations. This paper first describes and motivates the proposed C-TPN modeling language and its formal semantics. Then, a Uppaal translation is shown. Finally, three models of embedded real-time systems are considered, and their properties are thoroughly verified.

Download

A K-Means Variation Based on Careful Seeding and Constrained Silhouette Coefficients

Lecture notes in networks and systems, 2024

International Workshop on Cyber-Physical Systems

Nigro tutorial ACM/IEEE Distributed Simulation and Real-Time Applications 2019

IEEE DSRT, 2019

Theatre is a variant of the classical actors model, with a design volition to supporting both gen... more Theatre is a variant of the classical actors model, with a design volition to supporting both general but mainly timed distributed software systems, based either on real-timeor simulated-time.
Theatre is currently implemented in Java. Other languages are possible.
Main differences from classical actors are:
An absence of a local mailbox into each actor.
An absence of a local thread per actor.
An introduction of a reflective control-layer, customizable by programming, which is in charge of time-management, message scheduling and dispatching.
A flexibility to work with different timing models and programming styles.
The lightweight character of Theatre actors was designed so as to favortime predictability in time-sensitive applications

Performance of Parallel K-Means Algorithms in Java

Algorithms, Mar 29, 2022

This article is an open access article distributed under the terms and conditions of the Creative... more

Download

Advanced backtracking in Modula-2

Modelling and Analysis of Cyber-Physical Systems using Deterministic Theatre

2020 Fourth World Conference on Smart Trends in Systems, Security and Sustainability (WorldS4), 2020

This paper proposes an original variant of the Theatre actor system which is best suited to model... more This paper proposes an original variant of the Theatre actor system which is best suited to modelling analysis and implementation of cyber-physical systems (CPS). Novel in the proposal is the use of deterministic timed actors. More in particular, Deterministic Theatre is proposed which, although based on asynchronous message passing, adopts a deterministic precedence constraint technique which regulates the delivery order of simultaneous messages. Such provision proves effective for correctness analysis of CPS models through exhaustive model checking, and for transforming an analyzed model into a compliant implementation. The constrained delivery order improves the model checking performance by reducing the partial order otherwise existing in the timed transition system of the model. The paper introduces Deterministic Theatre and shows its concrete support on top of the Uppaal timed automata language and toolbox. A CPS modelling case study concerning a train-door controller is presented, which is used as a running analysis example throughout the paper. Finally, conclusions are drawn with an indication of ongoing and future work concerning Deterministic Theatre.

An Approach Based on Simulation and Verification for the Schedulability Analysis of Real-Time Systems

Summer Computer Simulation Conference, 2005

A Case Study Using Modular Time Petri Nets and Distributed Simulation

Development of a multimedia QoS synchronizer using AspectJ

Modelling and Analysis of Dynamic-Priority Real-Time Systems

Summer Computer Simulation Conference, 2006

Fast and Accurate K-means Clustering Based on Density Peaks

Lecture notes in networks and systems, 2023

Formal Modelling and Verification of Real-Time Self-Adaptive Systems

This paper describes a formal approach to modelling and verification of self-adaptive real-time s... more This paper describes a formal approach to modelling and verification of self-adaptive real-time systems. Such systems can dynamically be affected by exception events either originated in the operational environment or in the internal status, which require to be dealt with through adaptation actions which have to fulfil timing constraints. The approach is based on Time Basic (TB) Petri nets, a formalism well-suited to the specification of time-critical systems. Although some specialcase tools have been developed to support the analysis of TB net models, the original contribution of this paper is an embedding of TB nets into the popular Uppaal toolbox based on timed automata, which makes it possible both non-deterministic exhaustive analysis by model checking and/or a quantitative analysis of model properties through statistical model checking. The paper demonstrates the application of TB net modelling and analysis through a self-healing time-critical system.

A Measurement Laboratory over the Internet Based on Jini

Efficient and Reliable Clustering by Parallel Random Swap Algorithm

Petri Net Tools for Modelling and Simulation of Complex Systems

Performance of Parallel K-Means Based on Theatre

Model continuity in cyber-physical systems: A control-centered methodology based on agents

Simulation Modelling Practice and Theory, Apr 1, 2018

Abstract A Cyber Physical System (CPS) is given by the integration of cyber and physical componen... more Abstract A Cyber Physical System (CPS) is given by the integration of cyber and physical components, usually with feedback loops, where physical processes affect computations and vice versa. Design and implementation of complex CPSs is a multidisciplinary and demanding task. Challenges arise especially for the exploitation of heterogeneous and different models during the various phases of system life cycle. This paper proposes an agent-based and control-centric methodology which is well suited for the development of complex CPSs. The approach is novel and supports model continuity which enables the use of a unique model along all the development stages of a system ranging from analysis, by simulation, down to real-time implementation and execution. In the paper, basic concepts of the methodology are provided together with implementation details. Effectivenesses of the approach is demonstrated through a case study concerning a prototyped CPS devoted to the optimization of power consumption in a smart micro-grid automation system.

A service-based enactment engine for dynamically recongurable workflows

Parallel random swap: An efficient and reliable clustering algorithm in Java

Simulation Modelling Practice and Theory, Apr 1, 2023

Libero Nigro

Uploads

Papers by Libero Nigro

Log In