ETDs

This collection includes most of the ASU Theses and Dissertations from 2011 to present. ASU Theses and Dissertations are available in downloadable PDF format; however, a small percentage of items are under embargo. Information about the dissertations/theses includes degree information, committee members, an abstract, supporting data or media.

In addition to the electronic theses found in the ASU Digital Repository, ASU Theses and Dissertations can be found in the ASU Library Catalog.

Dissertations and Theses granted by Arizona State University are archived and made available through a joint effort of the ASU Graduate College and the ASU Libraries. For more information or questions about this collection contact or visit the Digital Repository ETD Library Guide or contact the ASU Graduate College at gradformat@asu.edu.

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From Formal Requirement Analysis to Testing and Monitoring of Cyber-Physical Systems

Description
Cyber-Physical Systems (CPS) are being used in many safety-critical applications. Due to the important role in virtually every aspect of human life, it is crucial to make sure that a CPS works properly before its deployment. However, formal verification of CPS is a computationally hard problem. Therefore, lightweight verification methods…

Cyber-Physical Systems (CPS) are being used in many safety-critical applications. Due to the important role in virtually every aspect of human life, it is crucial to make sure that a CPS works properly before its deployment. However, formal verification of CPS is a computationally hard problem. Therefore, lightweight verification methods such as testing and monitoring of the CPS are considered in the industry. The formal representation of the CPS requirements is a challenging task. In addition, checking the system outputs with respect to requirements is a computationally complex problem. In this dissertation, these problems for the verification of CPS are addressed. The first method provides a formal requirement analysis framework which can find logical issues in the requirements and help engineers to correct the requirements. Also, a method is provided to detect tests which vacuously satisfy the requirement because of the requirement structure. This method is used to improve the test generation framework for CPS. Finally, two runtime verification algorithms are developed for off-line/on-line monitoring with respect to real-time requirements. These monitoring algorithms are computationally efficient, and they can be used in practical applications for monitoring CPS with low runtime overhead.
ContributorsDokhanchi, Adel (Author) / Fainekos, Georgios (Thesis advisor) / Lee, Yann-Hang (Committee member) / Sarjoughian, Hessam S. (Committee member) / Shrivastava, Aviral (Committee member) / Arizona State University (Publisher)
Created2017
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A Methodology and Formalism to Handle Timing Uncertainties in Cyber-Physical Systems

Description
Uncertainty is intrinsic in Cyber-Physical Systems since they interact with human and work with both analog and digital worlds. Since even minute deviation from the real values can make catastrophe in a safety-critical application, considering uncertainties in CPS behavior is essential. On the other side, time is a…

Uncertainty is intrinsic in Cyber-Physical Systems since they interact with human and work with both analog and digital worlds. Since even minute deviation from the real values can make catastrophe in a safety-critical application, considering uncertainties in CPS behavior is essential. On the other side, time is a foundational aspect of Cyber-Physical Systems (CPS). Correct timing of system events is critical to optimize responsiveness to the environment, in terms of timeliness, accuracy, and precision in the knowledge, measurement, prediction, and control of CPS behavior. In order to design a more resilient and reliable CPS, first and foremost, there should be a way to specify the timing constraints that a constructed Cyber-Physical System must meet with considering existing uncertainties. Only then, we can seek systematic approaches to check if all timing constraints are being met, and develop correct-by-construction methodologies. In this regard, Timestamp Temporal Logic (TTL) is developed to specify the timing constraints on a distributed CPS. By TTL designers can specify the timing requirements that a CPS must satisfy in a succinct and intuitive manner and express the tolerable error as a part of the language. The proposed deduction system on TTL (TTL reasoning system) gives the ability to check the consistency among expresses system specifications and simplify them to be implemented on FPGA for run-time verification. Regarding CPS run-time verification, Timestamp-based Monitoring Approach(TMA) has been designed that can hook up to a CPS and take its timing specifications in TTL and verify if the timing constraints are being met with considering existing uncertainties in the system. TMA does not need to compute whether the constraint is being met at each and every instance of time but it re-evaluates constraint only when there is an event that can affect the outcome. This enables it to perform online timing monitoring of CPS for less computation and resources. Furthermore, the minimum design parameters of the timing CPS that are required to enable testing the timing of CPS are defined in this dissertation
ContributorsMehrabian, Mohammadreza (Author) / Shrivastava, Aviral (Thesis advisor) / Ren, Fengbo (Committee member) / Sarjoughian, Hessam (Committee member) / Derler, Patricia (Committee member) / Arizona State University (Publisher)
Created2021