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See discussions, stats, and author profiles for this publication at: https://www.researchgate.net/publication/278026905 Slides for the Ph.D. jury Data · June 2015 CITATIONS READS 0 128 1 author: Fernando Tricas University of Zaragoza 56 PUBLICATIONS 895 CITATIONS SEE PROFILE Some of the authors of this publication are also working on these related projects: Structural properties of Petri Nets and evolutionary algorithms View project Create new project "Structural based approaches for deadlock prevention in concurrent systems" View project All content following this page was uploaded by Fernando Tricas on 11 June 2015. The user has requested enhancement of the downloaded file.

Deadlock analysis, prevention and avoidance in Sequential Resource Allocation Systems Fernando Tricas Garc´ ıa Director: Dr. Joaqu´ ın Ezpeleta Departamento de Inform´ atica e Ingenier´ ıa de Sistemas Universidad de Zaragoza Deadlock analysis, prevention and avoidance in Sequential Resource Allocation Systems– p.1/49

� � ✁ ✂ � ✁ ✄ � � Outline Framework Deadlock prevention in Deadlock avoidance in Parallel computation of siphons Conclusions Deadlock analysis, prevention and avoidance in Sequential Resource Allocation Systems– p.2/49

� � � � � � Objectives Study of deadlock problems in Sequential Resource Allocation Systems (RAS), concentrating on Flexible Manufacturing Systems. Solving the deadlock avoidance and prevention problems for less restrictive classes of systems, using: Formal methods (Petri nets) An structural approach State equation Structure of the Petri net Deadlock analysis, prevention and avoidance in Sequential Resource Allocation Systems– p.3/49

� � � � Framework Resource Allocation Systems (RAS) A set of processes A set of (reusable) resources They have a concurrent nature Objective: to con- trol the system so that no deadlock can occur Deadlock analysis, prevention and avoidance in Sequential Resource Allocation Systems– p.4/49

� � � � What to do? R e a l S y s t e m C o n t r o ll er The Ostrich algorithm Deadlock detection and recovery Deadlock avoidance Deadlock prevention Deadlock analysis, prevention and avoidance in Sequential Resource Allocation Systems– p.5/49

� � � � What to do? C o n t r o ll er R e a l S y s t e m ( P N ) m o d e l S c h e du l er .... C o n t r o ll er D e a d l o c k avo i d a n ce a l go r i t h m The Ostrich algorithm Deadlock detection and recovery Deadlock avoidance Deadlock prevention Deadlock analysis, prevention and avoidance in Sequential Resource Allocation Systems– p.5/49

� � � � What to do? C o n t r o ll er R e a l S y s t e m ( P N ) m o d e l S c h e du l er .... C o n t r o ll er D e a d l o c k avo i d a n ce a l go r i t h m The Ostrich algorithm Deadlock detection and recovery C o n t r o ll er Deadlock avoidance ( P N ) m o d e l : S c h e du l er s y s t e m + .... Deadlock prevention c o n t r o l Deadlock analysis, prevention and avoidance in Sequential Resource Allocation Systems– p.5/49

� � � � � � � � Different subclasses Constraints on the process structure Sequential/concurrent? (S–RAS/NS–RAS) On–line routing decisions? Internal cyclic behavior (recirculation)? Constraints on how resources are acquired/released One/several resources at each state ? How are they acquired/released? One/several types at a time? Deadlock analysis, prevention and avoidance in Sequential Resource Allocation Systems– p.6/49

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