Generalized Fair Reachability Analysis for Cyclic Protocols

In this paper, the notion of fair reachability is generalized to cyclic protocols with $n\geq 2$ machines. Substantial state reduction can be achieved via fair progress state exploration. It is shown that the fair reachable state space is exactly the set of reachable states with equal channel length. As a result, deadlock detection is decidable for ${\cal P}$, the class of cyclic protocols whose fair reachable state spaces are finite. The concept of simultaneous unboundedness is defined and the lack of it is shown to be a necessary and sufficient condition for a protocol to be in ${\cal P}$. Through finite extension of the fair reachable state space, it is also shown that detection of unspecified receptions, unboundedness, and nonexecutable transitions are all decidable for ${\cal P}$. Furthermore, it is shown that any protocol ${\cal P}$ is logically correct if and only if there is no logical error in its fair reachable state space. This study shows that for the class ${\cal P}$, our generalized fair reachability analysis technique not only achieves substantial state reduction but also maintains very competitive logical error coverage. Therefore, it is a very useful technique to prove logical correctness for a wide variety of cyclic protocols

Generalized Fair Reachability Analysis for Cyclic Protocols with Nondeterminism and Internal Transitions

In this paper, we extend the generalized fair reachability notion to cyclic protocols with nondeterminism and internal transitions. By properly incorporating internal transitions into the formulation of fair progress vectors, we prove that most of the results established for cyclic protocols without nondeterminism and internal transitions still hold even if nondeterminism and internal transitions are allowed. We identify indefiniteness as a new type of logical error resulting from reachable internal execution cycles and show that indefiniteness can also be detected for the class of cyclic protocols with finite fair reachable state spaces with finite extensions

A tool for model-checking Markov chains

Markov chains are widely used in the context of the performance and reliability modeling of various systems. Model checking of such chains with respect to a given (branching) temporal logic formula has been proposed for both discrete [34, 10] and continuous time settings [7, 12]. In this paper, we describe a prototype model checker for discrete and continuous-time Markov chains, the Erlangen-Twente Markov Chain Checker EÎMC2, where properties are expressed in appropriate extensions of CTL. We illustrate the general benefits of this approach and discuss the structure of the tool. Furthermore, we report on successful applications of the tool to some examples, highlighting lessons learned during the development and application of EÎMC2

Petri net modeling and performance analysis of can fieldbus

The CAN FB (Controller Area Network FieldBus) has been in existence for ten years. It supports automated manufacturing and process control environments to interconnect intelligent devices such as valves, sensors, and actuators. CAN FieldBus has a high bit rate and the ability to detect errors. It is immune to noise and resistant to shock, vibration, and heat. Two recently introduced mechanisms, Distributed Priority Queue (DPQ) and Priority Promotion (PP) enable CAN FieldBus networks to share out the system bandwidth and grant ail upper bound on the transmission times so as to meet the requirements in real-time communications. Modeling and analysis of such networks are an important research area for their wide applications in manufacturing automation. This thesis presents a Petri net methodology which models and analyzes CAN FieldBus access protocol. A Reachability Graph of the Petri net model is -utilized to study the behavioral properties of the protocol. A timed Petri net simulator is used to evaluate the performance of the protocol. Performance measures include the completion time for successful events and operations. Operational parameters investigated using the Petri Net model are FieldBus speed, the length of each frame, and the number of frames in a message

Techniques of petri net reduction

Petri Nets have the capability to analyze large and complex concurrent systems. However, there is one constraint. The number of reachability states of the concurrent systems outweighs the capability of Petri Nets. Previous Petri Net reduction techniques focussed on reducing a subnet to a single transition and hence not powerful enough to reduce a Petri Net. This paper presents six reduction rules and discusses their drawbacks. A new reduction technique called Knitting Technique to delete paths of a Petri Net while retaining all the properties of the original net is presented. Further Structural matrix which facilitates reduction is presented

Control design for hybrid systems with TuLiP: The Temporal Logic Planning toolbox

This tutorial describes TuLiP, the Temporal Logic Planning toolbox, a collection of tools for designing controllers for hybrid systems from specifications in temporal logic. The tools support a workflow that starts from a description of desired behavior, and of the system to be controlled. The system can have discrete state, or be a hybrid dynamical system with a mixed discrete and continuous state space. The desired behavior can be represented with temporal logic and discrete transition systems. The system description can include uncontrollable variables that take discrete or continuous values, and represent disturbances and other environmental factors that affect the dynamics, as well as communication signals that affect controller decisions