A Tabular Expression Toolbox for Matlab/Simulink

J Software Evolu Process

Maibaum

et al. 2021

Self Cite

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).

Section: A Formal Frameworkmentioning

confidence: 99%

“…In our framework, we use tabular expressions to formalize informal system requirements. The requirements models development and its validation are done together in the TET 24 tool. The development of requirements models guarantees the properties of disjointness and completeness.…”

Section: Lesson Learnedmentioning

confidence: 99%

A formal approach to rigorous development of critical systems

Singh

J Software Evolu Process

Maibaum

et al. 2021

Self Cite

“…Similar constraints apply to the subconditions, if any. These properties can often be easily checked automatically using SMT solvers or a theorem prover such as PVS [6].…”

Section: Preliminariesmentioning

confidence: 99%

Formalizing and Verifying Function Blocks Using Tabular Expressions and PVS

Pang

Wang

Communications in Computer and Information Science

et al. 2014

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Abstract. Many industrial control systems use programmable logic controllers (PLCs) since they provide a highly reliable, off-the-shelf hardware platform. On the programming side, function blocks (FBs) are reusable components provided by the PLC supplier that can be combined to implement the required system behaviour. A higher quality system may be realized if the FBs are pre-certified to be compliant with an international standard such as IEC 61131-3. We present an approach to formalizing FB requirements using tabular expressions, and to verifying the correctness of the FBs implementations in the PVS proof environment. We applied our approach to the example FBs of IEC 61131-3 and identified issues in the standard: ambiguous behavioural descriptions, missing assumptions, and erroneous implementations.

“…The important thing to note from the example is that it is easy to inspect that the table is complete and disjoint. Further, these properties of the table can be easily formally verified by using a tool such as [9].…”

Section: A Brief Introduction To Assurancementioning

confidence: 99%

Insulin Pump Software Certification

Chen

Foundations of Health Information Engineering and Systems

Wang

et al. 2014

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Abstract. The insulin pump is a safety-critical embedded medical device used for treatment of type 1 and insulin treated type 2 diabetes. Malfunction of the insulin pump will endanger the user's life. All countries impose some regulation on the sale and use of medical devices. The purpose of such regulation is to protect the public by imposing standards of safety for medical devices, including insulin pumps. The regulator in the USA, the USA Food and Drug Administration (FDA), actually goes further, and includes efficacy in the regulatory requirement. Until recently, regulatory approval was dependent on process based guidance. However, this has proven to be inadequate in some (most) cases where the device depends on software for its safe and effective operation, and the FDA recently changed its approval process for infusion pumps (including insulin pumps), so that the production of an assurance case that demonstrates that the device is safe and effective is now a strongly suggested regulatory requirement. However the current regulatory guidance does not recommend any particular software development methodology, and does not include definitive guidance on the evaluation component of the certification process. In this paper, we briefly review the related USA regulatory standards for insulin pumps, highlight development and certification challenges, briefly discuss attributes of a safe, secure and dependable insulin pump, and propose an effective certification process for insulin pumps.