Alan Wassyng | McMaster University (original) (raw)

Papers by Alan Wassyng

IEEE Access

System logs play an important role in software development and system maintenance. Many system so... more System logs play an important role in software development and system maintenance. Many system software programs continuously generate system logs during software runtimes for failure detection and diagnosis purposes. Currently, the analysis of system log data is mainly a manual process that highly depends on human knowledge and experience. This time-consuming task has become a problem because of the ever-increasing volume of log data. Existing studies have investigated machine learning and deep learning techniques to automate the failure detection task. This paper takes the deep learning approach and proposes two detection structures based on recurrent and convolutional neural networks. More importantly, this paper takes a step further by closely examining the timestamps of log data which existing studies have generally ignored. This study found that time information can be a distinguishing factor between regular and abnormal log sequences. Inspired by this observation, a novel method is proposed to integrate log timestamps in deep learning models using interpolation techniques. The evaluation results show that the log timestamps can significantly improve the performance of failure detection. Cross-comparison of the different models demonstrates that the proposed network structure can successfully utilize the timestamp information. The code is available on GitHub: https://github.com/hfyxin/Ts-models-log-data-analysis.git.

Journal of Software: Evolution and Process, 2021

Safety critical systems, such as medical, automotive, and avionics systems, play an important rol... more Safety critical systems, such as medical, automotive, and avionics systems, play an important role in our daily lives. Increasing demand for new technologies in these safety critical systems requires rapid adoption of commercial hardware and software. However, the adoption of new hardware and software increases life‐threatening vulnerabilities. To aid in the reduction of these vulnerabilities and system failures, this paper proposes a framework based on formal methods for developing safety‐critical systems from requirements analysis to code generation. This framework includes a development process for documenting system requirements using tabular expressions, automatic formal model generation from the documented requirements, verification and validation of the generated formal models using proof techniques and animations, interactive simulation for validating the required behavior of the developed models by enabling domain experts to observe the system states according to, and finally, code generation from the formal model into a desired language. A prototype toolchain is developed to automate this framework. An assessment of the proposed framework is undertaken through a case study: insulin infusion pump (IIP).

Current Opinion in Psychiatry, 2005

Lecture Notes in Computer Science, 2022

Recent Trends and Advances in Model Based Systems Engineering, 2022

2019 IEEE 30th International Symposium on Software Reliability Engineering (ISSRE), 2019

An assurance case (AC) captures explicit reasoning associated with assuring critical properties, ... more An assurance case (AC) captures explicit reasoning associated with assuring critical properties, such as safety. A vital attribute of an AC is that it facilitates the identification of fallacies in the validity of any claim. There is considerable published research related to confidence in ACs, which primarily relate to a measure of soundness of reasoning. Evaluation of an AC is more general than measuring confidence and considers multiple aspects of the quality of an AC. Evaluation criteria thus play a significant role in making the evaluation process more systematic. This paper contributes to the identification of effective evaluation criteria for ACs, the rationale for their use, and initial tests of the criteria on existing ACs. We classify these criteria as to whether they apply to the structure of the AC, or to the content of the AC. This paper focuses on safety as the critical property to be assured, but only a very small number of the criteria are specific to safety, and can serve as placeholders for evaluation criteria specific to other critical properties. All of the other evaluation criteria are generic. This separation is useful when evaluating ACs developed using different notations, and when evaluating ACs against safety standards. We explore the rationale for these criteria as well as the way they are used by the developers of the AC and also when they are used by a third-party evaluator.

Bibliographic information published by the Deutsche Nationalbibliothek The Deutsche Nationalbibli... more Bibliographic information published by the Deutsche Nationalbibliothek The Deutsche Nationalbibliothek lists this publication in the Deutsche Nationalbibliografie; detailed bibliographic data are available in the Internet at http://dnb.d-nb.de. License This work is licensed under a Creative Commons Attribution 3.0 Unported license: CC-BY. In brief, this license authorizes each and everybody to share (to copy, distribute and transmit) the work under the following conditions, without impairing or restricting the authors' moral rights: Attribution: The work must be attributed to its authors. The copyright is retained by the corresponding authors. Digital Object Identifier: 10.4230/DagRep.4.2.i Aims and Scope The periodical Dagstuhl Reports documents the program and the results of Dagstuhl Seminars and Dagstuhl Perspectives Workshops. In principal, for each Dagstuhl Seminar or Dagstuhl Perspectives Workshop a report is published that contains the following: an executive summary of the seminar program and the fundamental results, an overview of the talks given during the seminar (summarized as talk abstracts), and summaries from working groups (if applicable). This basic framework can be extended by suitable contributions that are related to the program of the seminar, e.g. summaries from panel discussions or open problem sessions.

Computing in Science & Engineering, 2021

Assurance cases provide an organized and explicit argument for correctness. They can dramatically... more Assurance cases provide an organized and explicit argument for correctness. They can dramatically improve the quality of scientific software. Assurance cases are already effectively used for real-time safety critical systems. Their advantages for scientific software include engaging domain experts, producing only necessary documentation, and providing evidence that can be verified/replicated. This article illustrates assurance cases through the correctness case for 3dfim+, software for analyzing activity in the brain. The example justifies the value of assurance cases for scientific software, since the existing documentation is shown to have ambiguities and omissions, such as an incompletely defined ranking function and missing details on the coordinate system. We identified a serious concern for 3dfim+: running the software does not produce any warning about the necessity of using data that matches the parametric statistical model employed for the correlation calculations. Raising the bar for scientific software is both feasible and necessary.

Proceedings of the 40th International Conference on Software Engineering: Companion Proceeedings, 2018

Assurance cases, which provide an organized and explicit argument for correctness, should be used... more Assurance cases, which provide an organized and explicit argument for correctness, should be used for certifying Scientific Computing Software (SCS), especially when the software impacts health and safety. Assurance cases have already been effectively used for safety cases for real time systems. Their advantages for SCS include engaging domain experts, producing only necessary documentation, and providing evidence that can potentially be verified/replicated by a third party. This paper illustrates assurance cases for SCS through the correctness case for 3dfim+, an existing medical imaging application. No errors were found in 3dfim+. However, the example still justifies the value of assurance cases, since the existing documentation is shown to have ambiguities and omissions, such as an incompletely defined ranking function and missing details on the coordinate system convention adopted. In addition, a potential concern for the software itself is identified: running the software does not produce any warning about the necessity of using data that matches the assumed parametric statistical model.

2017 IEEE International Symposium on Software Reliability Engineering Workshops (ISSREW), 2017

A failure in a critical system can cause death, injury, financial loss, and environmental damage.... more A failure in a critical system can cause death, injury, financial loss, and environmental damage. To develop safe and trustworthy systems, we need to plan the development and assessment of system functionality in advance. Assurance Cases are a generalization of Safety Cases, and are gaining momentum as a preferred way of demonstrating assurance of critical properties in complex software-intensive systems. To cope with the lack of standardized assurance structures, and to encourage safety assessment prior to development, we previously proposed the use of an assurance case template. The principles presented here can be used to build an assurance case template that complies with the functional safety standard, ISO 26262 in a cost-effective way. In the future, such principles may lead to semi-automated development of these templates.

ArXiv, 2020

Model-Based Development (MBD) is widely used for embedded controls development, with Matlab Simul... more Model-Based Development (MBD) is widely used for embedded controls development, with Matlab Simulink being one of the most used modelling environments in industry. As with all software, Simulink models are subject to evolution over their lifetime and must be maintained. Modularity is a fundamental software engineering principle facilitating the construction of complex software, and is used in textual languages such as C. However, as Simulink is a graphical modelling language, it is not currently well understood how modularity can be leveraged in development with Simulink, nor whether it can be supported with current Simulink modelling constructs. This paper presents an effective way of achieving modularity in Simulink by introducing the concept of a Simulink module. The effectiveness of the approach is measured using well-known indicators of modularity, including coupling and cohesion, cyclomatic complexity, and information hiding ability. A syntactic interface is defined in order t...

SAE International Journal of Engines, 2021

2021 ACM/IEEE 24th International Conference on Model Driven Engineering Languages and Systems (MODELS), 2021

Proceedings of the 28th ACM Joint Meeting on European Software Engineering Conference and Symposium on the Foundations of Software Engineering, 2020

Lecture Notes in Computer Science, 2016

The trip computers for the two reactor shutdown systems of the Ontario Power Generation (OPG) Dar... more The trip computers for the two reactor shutdown systems of the Ontario Power Generation (OPG) Darlington Nuclear Power Generating Station (DNGS) are being refurbished due to hardware obsolescence. For one of the systems, the general purpose computer originally used is being replaced by a programmable logic controller (PLC). The trip computer application software has been rewritten using function block diagrams (FBDs), a commonly used PLC programming language defined in the IEC 61131-3 standard. The replacement project's quality assurance program requires that formal verification be performed to compare the FBDs against a formal software requirements specification (SRS) written using tabular expressions (TEs). The PVS theorem proving tool is used in the formal verification. Custom tools developed for OPG are used to translate TEs and FBDs into PVS code. In this paper, we present a method to rigorously translate the graphical FBD language to a mathematical model in PVS using an abstract syntax to represent the FBD constructs. We use an example from the replacement project to demonstrate the use of the model to translate a FBD module into a PVS specification.