Program Overview
08:45 Opening Remark (Francesco Basile, Mariagrazia Dotoli)
08:50 José Manuel Colom “A Petri net perspective of the deadlock problem in multithreaded software applications observed as Resource Allocation Systems”
09:35 Spyros Reveliotis “A structural characterization of liveness and reversibility for Petri nets modeling complex Resource Allocation Systems”
10:20 Coffee Break
10:40 MengChu Zhou “Roles of Petri nets in optimal scheduling of cluster tools in wafer fabrication”
11:25 Bengt Lennartson “Optimization of hybrid Petri nets for energy reduction of robot cells”
13:20 Mariagrazia Dotoli “A survey on Petri nets models for logistics and transportation systems”
14:05 Cristian Mahulea “Path planning and motion control of mobile robots using Petri nets”
14:50 Coffee Break
15:10 Vincent Augusto “Petri nets applied to health-care systems”
15:55 Francesco Basile “A formal model approach to warehouse systems modelling and control”
16:40 Closing Remark (Mariagrazia Dotoli, Francesco Basile)
Discrete event systems (DES) are a particular class of dynamic systems whose main feature is that their evolution is governed by the occurrence of asynchronous events that are generally not numerical. This class of systems attracted recently the attention of many researchers since many phenomena in man-made systems cannot be described using the classical models of time-driven processes, e.g., differential or difference equations. Several are the application domains in this field: manufacturing, process control, software engineering, transportation, and so on. Various mathematical formalisms have been developed for this class of highly complex systems. This workshop focuses on one of them, namely Petri nets (PNs). PNs have been specifically designed to model systems with interacting components and as such are able to capture many features of DES, such as concurrency, asynchronous operations, deadlocks, conflicts, etc. Furthermore, the PN formalism may be used to describe several classes of logical models (e.g., P/T nets, labeled P/T nets, Colored PNs, nets with inhibitor arcs), performance models (e.g., Timed PNs, Time PNs, Stochastic PNs), continuous and hybrid models (continuous PNs, hybrid PNs). Some of these models are considered in the workshop and it is shown how they can be successfully applied in different industrial areas, all related to the topics of CASE 2015. The workshop includes eight applications: deadlock handling in multithreaded software, liveness and reversibility analysis of resource allocation systems, optimal scheduling and real-time control of single and multi-cluster tools, energy optimization of robot cells, logistics and transportation systems, path planning and motion control of mobile robots, health-care systems, and warehouse systems.
List of topics and their descriptions:
The workshop consists of seven presentations, whose titles and authors are listed in the following.
Before lunch:
1. A Petri net perspective of the deadlock problem in multithreaded software applications observed as Resource Allocation Systems
José Manuel Colom
The focus of the presentation is on the study of the deadlock problem due to shared resource allocation in multithreaded software like streaming applications running over cloud infraestructures. Petri nets have a success story as models aimed at the study of Resource Allocation Systems (RASs) from a systemic perspective. An RAS is a discrete event system in which a set of concurrent processes coexist, and these must compete in order to be granted the allocation of some shared resources. The main goal of the talk is to provide a profound and more general insight on the liveness problem in RASs with sequential processes and serially reusable resources, particularly from the perspective of dealing with multithreaded software correction. This includes the proposal of a Petri net-based design methodology, the review and integration of previous results in the new framework, the production of efficient liveness analysis algorithms for the new Petri net class, as well as the proposition of efficient methods for overcoming deadlock problems in the real system.
2. A structural characterization of liveness and reversibility for Petri nets modeling complex Resource Allocation Systems
Spyros Reveliotis
In many modern technological applications, part of the control function involves the allocation of a finite set of reusable resources to a set of concurrently executing processes in a way that deadlocks are avoided and every running process can proceed to its successful completion. The corresponding problem has been studied through the formal abstraction of resource allocation systems (RAS), and Petri nets (PNs) have been a popular modeling framework for the rigorous representation and analysis of RAS behavior. More specifically, in the PN modeling framework, the RAS deadlock avoidance problem reduces to the analysis of the liveness and reversibility of the RAS-modeling PNs. Central role in this analysis holds the structural objects of “empty and deadly marked siphons” since (a) they provides a formal explanation of any arising non-liveness in the considered PN class by means of standard PN concepts and primitives, and (b) enable the assessment of these properties for any RAS-modeling PN while avoiding the explicit enumeration of the underlying state space, which can be a challenging task even for moderately sized RAS.
This talk will review the problem of the structural analysis of RAS-modeling PNs for liveness and reversibility by means of deadly marked siphons, focusing on a series of results in this area that have been derived by the presenter and his collaborators. Special emphasis will be given on (i) the interpretation of these results through a series of motivational arguments and examples, and (ii) the employment of the presented results towards the development of efficient tools for liveness and reversibility analysis and enforcement in the considered PN class.
3. Roles of Petri nets in optimal scheduling of cluster tools in wafer fabrication
MengChu Zhou
This talk intends to clarify the roles that Petri nets can play in the optimal scheduling and real-time control of single and multi-cluster tools that are widely used in semiconductor manufacturing industry. We illustrate how to use Petri nets to model various wafer production features involved in these highly expensive robotic manufacturing systems. Then we show how to use the resultant Petri net models to establish various schedulability conditions and derive extremely efficient algorithms that can compute optimal schedules for single and multi-cluster tools. When the bounded variation of activity time is caused in a fabrication process, we finally demonstrate how to adjust the scheduled robot wait time to offset such variation in order to achieve desired real-time optimal execution results. Our work focuses on those process-bounded cluster tools in which robots are fast enough such that they have some idle time in realizing an optimal schedule.
4. Optimization of hybrid Petri nets for energy reduction of robot cells
Bengt Lennartson
This talk starts with a presentation of predicate transition models, from which different types of modular Petri nets including shared variables are introduced. Especially various versions of hybrid Petri nets (HPNs) are explored, and a specific type of modular HPNs including explicit differential equations and communication by variables is proposed. It is then shown how this HPN model can be optimized based on a simple and robust nonlinear programming formulation. The procedure only assumes that desired sampled paths for a number of interacting moving devices are given, while originally equidistant time instances are adjusted to minimize a given criterion. This optimization of hybrid systems is also applied to a real robot
station with interacting devices, which results in about 40% reduction in energy consumption.
After lunch:
5. A survey on Petri nets models for logistics and transportation systems
Graziana Cavone, Mariagrazia Dotoli, Carla Seatzu
Logistics and transportation systems are man-made systems that are well suited for modeling in a discrete event system framework and particularly by Petri Nets (PNs), due to their different characteristics: distributed, parallel, deterministic, stochastic, discrete, and continuous. The paper presents a survey on the various Petri nets modeling frameworks proposed in the related literature for logistics and transportation systems, with applications to modeling, simulation, analysis, optimization and control. In particular, we focus on papers dealing with freight transportation and outline and classify the related works conducted using PNs as regards the proposed framework and addressed problems. We also debate the approaches viability, discussing contributions and limitations, and identify future research potentials.
6. Path planning and motion control of mobile robots using Petri nets
Cristian Mahulea
This talk presents some automated strategies for a team of agents that cooperate between them in order to accomplish high-level requirements (specifications). The common point of these strategies is the use of Petri nets to model the environment and/or the robot movements. The main advantage of using Petri net models instead of finite state automata is the scalability of the techniques when the number of robots of the team is increasing. We will briefly see first the techniques based on finite state automata models and we will argue that their extensions to Petri net models are not immediate. For some kind of specifications we show that the problem of computing trajectories is reduced to an (easy) reachability problem of state machine Petri nets, which can be easily solved using linear programming problems. Having a set of trajectories for each robot, other problem is to ensure a collision avoidance motion control when the robots chose randomly one trajectory. Using the deadlock prevention techniques of Resource Allocation Systems this problem can be solved.
7. Petri nets applied to health-care systems
Vincent Augusto
The field of operational research applied to health care systems evolved a lot during the last decade. Modern health care systems can be viewed as a complex network of institutions, health care professionals (both clinical and administrative), information systems and materials such as equipment and medications. Interactions between such entities are required to provide (i) better access, continuity and quality of care to patients, (ii) better working conditions for health care professionals, while (iii) compressing operating costs and investments in new technology and infrastructures.
In this presentation, new research directions to apply Petri nets to health-care systems are proposed. Several problems will be described: (i) unified modelling, analysis and simulation of various hospital departments using a special class of Petri nets and a generic modelling framework; (ii) health-care network design and care coordination for patient pathway (application to a cancer care network) where solutions are provided to optimize information transmission among the health-care professionals of such network, and (iii) health-care pathway prediction, where institutional databases are used to extract new information and better understand care pathway of patients among several hospitals, and translate such knowledge directly into Petri nets using process mining techniques. Conclusions and perspective of such research axes will also be given.
8. A formal model approach to warehouse systems modelling and control
Francesco Basile
As usual, the implementation of a control algorithm requires three preliminary steps: development of a reliable model; design of control procedures according to some optimality criteria; validation of these control procedures. This talk discusses the successful role of Petri nets to carry out the above mentioned steps in the context of warehouse systems.
Organizers:
Carla Seatzu, Department of Electrical and Electronic Engineering, University of Cagliari, Italy
Mariagrazia Dotoli, Department of Electrical and Information Engineering, Polytechnic of Bari, Italy
List of speakers and their biographical sketch:
1. José Manuel Colom received the PhD degree in industrial-electrical engineering from the University of Zaragoza, Zaragoza, Spain, in 1989. He is currently a professor in the Department of Computer Science and Systems Engineering, University of Zaragoza. His research interests include modeling, qualitative, and performance analysis, and implementation of discrete event systems using Petri nets. He has coauthored more than 100 research papers in technical journals and conferences. He has served on the technical committees of several international conferences in the field of formal methods and concurrent systems. He has organized, as a conference cochair, several international conferences in the field of Petri nets and discrete event systems.
2. Spyros Reveliotis is a Professor at the School of Industrial & Systems Engineering at the Georgia Institute of Technology. His research interests are in the area of Discrete Event Systems theory and its applications, with particular emphasis on the role of this theory in the modeling, analysis and control of complex resource allocation systems. He has held a number of editorial positions on the editorial boards of related journals and conferences, currently serving as a Senior Editor for the IEEE Trans. on Automation Science and Engineering, a Department Editor for IIE Trans., and an Associate Editor for the Journal of Discrete Event Dynamic Systems. Also, he has been a recipient of a number of awards, including the Kayamori Best Paper Award in the 1998 IEEE Intl. Conference on Robotics & Automation, and he is an IEEE Fellow.
3. MengChu Zhou (S’88-M’90-SM’93-F’03) received his B.S. degree in Control Engineering from Nanjing University of Science and Technology, Nanjing, China in 1983, M.S. degree in Automatic Control from Beijing Institute of Technology, Beijing, China in 1986, and Ph. D. degree in Computer and Systems Engineering from Rensselaer Polytechnic Institute, Troy, NY in 1990. He joined New Jersey Institute of Technology (NJIT), Newark, NJ in 1990, and is now a Distinguished Professor of Electrical and Computer Engineering. His research interests are in Petri nets, sensor networks, web services, big data, semiconductor manufacturing, transportation and energy systems. He has over 570 publications including 11 books, 270+ journal papers (over 180 in IEEE Transactions), and 22 book-chapters. He is the founding Editor of IEEE Press Book Series on Systems Science and Engineering, and Associate Editor of IEEE Transactions on Systems, Man and Cybernetics: Systems, IEEE Transactions on Industrial Informatics, and IEEE Transactions on Intelligent Transportation Systems. He has been Steering Committee Chair for IEEE International Conference on Automation Science and Engineering sicne 2012. He is a Fellow of International Federation of Automatic Control (IFAC) and American Association for the Advancement of Science (AAAS).
4. Bengt Lennartson received the Ph.D. degree in automatic control from Chalmers University of Technology, Gothenburg, Sweden, in 1986. Since 1999, he has been a Professor of the Chair of Automation, Department of Signals and Systems. He was Dean of Education at Chalmers University of Technology from 2004 to 2007, and since 2005 he is a Guest Professor at University West, Trollhättan. He has been a Visiting Professor at University of Newcastle, Australia and University of Cagliari, Italy. He was General Chair of WODES 2008 and Associate Editor for Automatica 2002-2005, and currently he is Co-Chair of the RAS-TC on Sustainable Production Automation, Associate Editor for IEEE Transaction on Automation Science and Engineering, and General Chair of IEEE CASE 2015. He is (co)author of two books and more than 260 peer reviewed international papers. His main areas of interest include discrete event and hybrid systems, especially for manufacturing applications, as well as robust feedback control.
5. Mariagrazia Dotoli received the Laurea degree in electronic engineering with honors in 1995 and the Ph.D. in electrical engineering in 1999, both from Politecnico di Bari (Italy). She has been a visiting scholar at the Paris 6 University and at the Technical University of Denmark. She is an expert evaluator of the European Commission since the 6th Framework Programme. She is currently an Associate Professor of the Department of Electrical and Information Engineering of Politecnico di Bari that she joined in 1999 as tenured Assistant Professor in Control Systems Engineering. She has been the Vice Rector for research of Politecnico di Bari for 4 years until 2013 and she a member elect of the Academic Senate of the same University for triennium 2012-2015. Her research interests include modeling, identification, management, control and diagnosis of discrete event systems, Petri nets, manufacturing systems, logistics systems, traffic networks. She is Associate Editor of the IEEE Transactions on Automation Science and Engineering and a member of the editorial board of the journals: Mediterranean Journal of Measurement and Control, International Journal of Automation and Control, International Journal of Systems Signal Control and Engineering Application, and International Journal of Discrete Event Control Systems. She is author or co-author of 150+ printed publications, including 1 book (in Italian) and 35+ papers on international journals. Her h-index equals 16.
6. Cristian Mahulea received the B.S. and M.Sc. degrees in control engineering from the Technical University of Iasi, Romania, in 2001 and 2002, respectively, and the Ph.D. degree in systems engineering from the University of Zaragoza, Spain, in 2007. He is currently an Assistant Professor at the Department of Computer Science and Systems Engineering of the University of Zaragoza, Spain.
His research interests include discrete event systems, hybrid systems, automated manufacturing, Petri nets, mobile robotics and healthcare systems. He has been a Visiting Professor at the University of Cagliari, Italy, and a Visiting Researcher at the University of Sheffield, U.K., and Boston University, MA, USA. He is actually Associate Editor of the IEEE Transactions on Automation Science and Engineering.
7. Vincent Augusto has been working in the healthcare engineering field since 2005, and received his Ph.D. in Industrial Engineering from the Ecole des Mines de Saint-Etienne (EMSE), France, in 2008, which focused on healthcare flow modeling using UML and Petri nets. Then he was a visiting scholar at CIRRELT (Centre Interuniversitaire de Recherche sur les Réseaux d’Entreprise, la Logistique et le Transport), University of Laval, Quebec, Canada in 2009. He worked on healthcare network modelling and integration of a mapping platform in a unified database. Since 2009, he is an assistant professor in the Department of Health-care Engineering at the EMSE. His research interests include modeling, simulation, optimization of health care systems and their supply-chains. Since 2010, he is focusing his research on healthcare networks engineering and design through 3 major axes (i) Performance evaluation and health-care engineering; (ii) Decision aid for healthcare; and (iii) Patient pathway prediction using Markov chains and process mining.
8. Francesco Basile was born in Naples, Italy, in 1971. He received the Laurea degree in Electronic Engineering in 1995 and the Ph.D. degree in Electronic and Computer Engineering in 1999 from the University of Naples. In 1999 he was visiting researcher for six months at the Departamento de Ingenieria Informatica y Systemas of the University of Saragoza, Spain. He is currently Associate professor of Automatic Control at the Dipartimento di Ingegneria Elettronica ed Ingegneria Informatica of the University of Salerno, Italy. He has published more than 90 papers on international journals and conferences.
He has been member of the editorial board of International Journal of Robotics and Automation. He is a member of the editorial board of IEEE Transactions on Control Systems Technology, IEEE Transactions on Automation Science and Engineering, and of IEEE Control System Society Conference Editorial Board. His current research interest are: modelling and control of discrete event systems, automated manufacturing and robotic, logistic and transportation systems. He is IEEE Senior member since November 2011.