The public defense of Jiale Zhou’s doctoral thesis in Computer Science and Engineering

Doctoral thesis and Licentiate seminars

Datum: 2018-01-12
Tid: 13.00
Plats: room Delta, MDH Västerås.

The public defense of Jiale Zhou’s doctoral thesis in Computer Science and Engineering will take place in room Delta, at 13.00 on January 12 at MDH Västerås.

Title: “An Ontological Approach to Safety Analysis of Safety-Critical Systems”.

Serial number: 251.

The faculty examiner is Lecturer Ibrahim Habli, University of York; and the examining committee consists of Professor Jelena Zdravkovic, Stockholm University; Adjunct Professor Mattias Nyberg, KTH Royal Institute of Technology; Professor Emeritus Tor Stålhane, the Norwegian University of Science and Technology.

Reserve; Docent Antonio Cicchetti, MDH.


Safety-critical systems (SCSs) are such systems that can result in great losses when they are involved in hazardous situations. In modern society, SCSs are becoming pervasive and an indispensable part of our daily life. They play an essential role in various human activities, such as medical treatment, daily transportation, space exploration, and operation of nuclear power plants. To avoid the occurrence of accidents, it is of significant importance to provide safety mechanisms for these systems. The safety mechanisms will prevent these systems from being involved in hazardous situations, i.e., hazards. To achieve this goal, system analysts need to identify potential hazards in which the system under analysis can be involved during its life-cycle. In addition, it is also important to analyze the causes of how and why the system is involved in the hazardous situation. As an old saying goes, “A good beginning is half the battle”. The earlier the system analysts can have a complete picture of potential hazards, the more and better design choices can be made to avoid accidents. However, it is not a trivial task to accomplish this goal. One big problem is that different analysts may have distinct understanding of what a hazard is, i.e., what components a hazard consists of. Therefore, the description of hazards identified by one analyst is at a risk of missing some components and can cause ambiguities for others. To improve this situation, we propose a definition of hazard in our research. In this definition, we have defined what components a hazard consists of, the relations between the components and how the components together can lead to an accident. This definition will help analysts achieve a consistent view of hazards. Moreover, based on this definition, an approach to identify hazards and their causes is proposed. According to the identified hazards and causes, safety mechanisms will be defined to prevent the systems from encountering accidents.