A system safety assurance case aims to demonstrate that a system is reasonably safe within the parameters defined according to its intended use. A system safety assurance case involves the definition of a Safety Engineering Process and its execution for the particular system. An essential element in the Safety Engineering Process is hazard analysis. An often used version of hazard analysis is HAZOP. HAZOP identifies hazards and hazardous events in the system's design. Traditionally, HAZOP is performed based on the expertise of a multi-disciplinary team. This team uses a heuristic based approach that results in documented output that often does not include adequate traceability as to how the output results were obtained. This thesis proposes a systematic approach to HAZOP that was developed after performing detailed analysis on how traditional HAZOP is performed in industry. It aims to produce documented output in which the output results are traceable to interim steps in the process. We call this systematic approach HAZOP+, because it was designed to provide sufficient detail so that it can form the basis of a HAZOP metamodel created in Workflow+ - a relatively new model driven methodology for developing assurance cases. Workflow+ has well-defined semantics, and so we refer to HAZOP+ as formalizable. HAZOP+ has a number of benefits over traditional HAZOP, and these benefits are demonstrated by comparing a traditional application of HAZOP with the application of HAZOP+, both applied to a typical Lane Keeping Assist feature. A long term objective of system safety assurance is to be able to perform incremental safety assurance, for example, by updating the system safety assurance case after a modification to the system or its environment. Since the safety assurance case for a system depends on elements of the Safety Engineering Process, as well as the outputs of that process, the ability to perform an incremental hazard analysis after a modification to the system or environment can be a real benefit. This thesis further describes how HAZOP+ can be enhanced/extended to HAZOPdelta - an incremental version of HAZOP+. / Thesis / Master of Applied Science (MASc)

Assurance Cases have been effectively used for improving the safety of real-time safety systems. However, until now, Assurance Case techniques have not been applied to building confidence in the correctness of Scientific Computing (SC) software. Our approach is to employ Assurance Case techniques to the case of a specific medical image analysis software, 3dfim+, and then generalize the results/template for other medical and SC software. Using the Goal Structuring Notation (GSN), we develop an Assurance Case to support the top goal that "Program 3dfim+ delivers correct outputs when used for its intended use/purpose in its intended environment." This claim is supported by several sub-claims, including the claims that high-quality requirements exist and that the implementation complies with the requirements. The full argument decomposes each sub-claim further until at the bottom level evidence is provided. The evidence provided includes the requirements documentation, test cases and expert review. To simplify the Assurance Case diagram, a new generic module, parameterized over quality, was developed to argue that each quality has been achieved. Evaluation of the full Assurance Case shows that this approach is feasible for building confidence in SC software, even in the practical situation where confidence is sought, but redesign and reimplementation are not possible. The exercise uncovered issues with the original documentation for 3dfim+, including missing assumptions, and ambiguity with the chosen sign convention. Furthermore, although no errors in output were found, the Assurance Case highlights that confidence in the original 3dfim+ software could be improved through additional checks for input validity. / Thesis / Master of Science (MSc)

As vehicles become more complex, the work required to ensure that they are safe increases enormously. This in turn results in a much more complicated task of testing systems, subsystems, and components to ensure that they are safe individually as well as when they are integrated. As a result, managing the safety engineering process for vehicle development is of major interest to all automotive manufacturers. The goal of this research is to introduce a tool that provides support for a new framework for modeling safety processes, which can partially address some of these challenges. WorkFlow+ is a framework that was developed to combine both data flow and process flow to increase traceability, enable users to model with the desired granularity safety engineering workflow for their products, and produce assurance cases for regulators and evaluators to be able to validate that the product is safe for the users and the public. With the development of an editor, it will bring WorkFlow+ to life. / Thesis / Master of Applied Science (MASc)

The topic of transparency in CSR reporting provides several opportunities for research. This dissertation contributes to three of them, over the course of three research manuscripts. Research on CSR reporting has produced an extensive literature. Scholars have reviewed this literature with varying extensiveness and points of view. However, the question whether CSR reports overall provide decision-useful information to capital markets has received little attention. Thus, the first manuscript provides such a review of the empirical literature and its major findings. One potential influence on the quality of CSR reports may be the fact whether a report is externally assured by an independent party. The second manuscript thus investigates how external assurance is associated with principles of CSR reporting quality at the firm level. The third manuscript is concerned with the practical implementation of transparency in CSR.