Document Type

Dissertation

Degree

Doctor of Philosophy (PhD)

Major/Program

Computer Science

First Advisor's Name

Xudong He

First Advisor's Committee Title

Committee chair

Second Advisor's Name

Jason Liu

Second Advisor's Committee Title

Committee member

Third Advisor's Name

Peter J. Clarke

Third Advisor's Committee Title

Committee member

Fourth Advisor's Name

Leonardo Bobadilla

Fourth Advisor's Committee Title

Committee member

Fifth Advisor's Name

Armando Barreto

Fifth Advisor's Committee Title

Committee member

Keywords

Formal Methods, High-level Petri nets, Hybrid Petri nets, Hybrid Automata, Cyber-Physical Systems, Hybrid Systems, Reachability Analysis, Modeling and Analysis

Date of Defense

7-1-2020

Abstract

Cyber-Physical Systems (CPSs) are software controlled physical devices that are being used everywhere from utility features in household devices to safety-critical features in cars, trains, aircraft, robots, smart healthcare devices. CPSs have complex hybrid behaviors combining discrete states and continuous states capturing physical laws. Developing reliable CPSs are extremely difficult. Formal modeling methods are especially useful for abstracting and understanding complex systems and detecting and preventing early system design problems. To ensure the dependability of formal models, various analysis techniques, including simulation and reachability analysis, have been proposed in recent decades. This thesis aims to provide a unified formal modeling and analysis methodology for studying CPSs.

Firstly, this thesis contributes to the modeling and analysis of discrete, continuous, and hybrid systems. This work enhances modeling of discrete systems using predicate transition nets (PrTNs) by fully realizing the underlying specification through incorporating the first-order logic with set theory, improving the type system, and providing incremental model composition. This work enhances the technique of analyzing discrete systems using PrTN by improving the simulation algorithm and its efficient implementation. This work also improves the analysis of discrete systems using SPIN by providing a more accurate and complete translation method.

Secondly, this work contributes to the modeling and analysis of hybrid systems by proposing an extension of PrTNs, hybrid predicate transition nets (HPrTNs). The proposed method incorporates a novel concept of token evolution, which nicely addresses the continuous state evolution and the conflicts present in other related works. This work presents a powerful simulation capability that can handle linear, non-linear dynamics, transcendental functions through differential equations. This work also provides a complementary technique for reachability analysis through the translation of HPrTN models for analysis using SpaceEx.

Identifier

FIDC009168

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