Formal Modelling, Testing and Verification of HSA Memory Models using Event-B

The HSA Foundation has produced the HSA Platform System Architecture Specification that goes a long way towards addressing the need for a clear and consistent method for specifying weakly consistent memory. HSA is specified in a natural language which makes it open to multiple ambiguous interpretations and could render bugs in implementations of it in hardware and software. In this paper we present a formal model of HSA which can be used in the development and verification of both concurrent software applications as well as in the development and verification of the HSA-compliant platform itself. We use the Event-B language to build a provably correct hierarchy of models from the most abstract to a detailed refinement of HSA close to implementation level. Our memory models are general in that they represent an arbitrary number of masters, programs and instruction interleavings. We reason about such general models using refinements. Using Rodin tool we are able to model and verify an entire hierarchy of models using proofs to establish that each refinement is correct. We define an automated validation method that allows us to test baseline compliance of the model against a suite of published HSA litmus tests. Once we complete model validation we develop a coverage driven method to extract a richer set of tests from the Event-B model and a user specified coverage model. These tests are used for extensive regression testing of hardware and software systems. Our method of refinement based formal modelling, baseline compliance testing of the model and coverage driven test extraction using the single language of Event-B is a new way to address a key challenge facing the design and verification of multi-core systems.Comment: 9 pages, 10 figure

ESPGHAN and NASPGHAN 2023 protocol for paediatric FAPD treatment guidelines (standard operating procedure)

Introduction To date, no international guidelines have been published for the treatment of paediatric functional abdominal pain disorders (FAPDs), subcategorised into functional abdominal pain–not otherwise specified (FAP-NOS), irritable bowel syndrome (IBS), functional dyspepsia and abdominal migraine (AM). We aim for a treatment guideline, focusing on FAP-NOS, IBS and AM, that appreciates the extensive array of available therapies in this field. We present the prospective operating procedure and technical summary protocol in this manuscript. Methods Grading of Recommendations, Assessment, Development and Evaluation (GRADE) will be followed in the development of the guideline, following the approach as laid out in the GRADE handbook, supported by the WHO. The Guideline Development Group (GDG) is formed by paediatric gastroenterologists from both the European Society for Pediatric Gastroenterology, Hepatology and Nutrition, as well as the North American Society for Pediatric Gastroenterology, Hepatology and Nutrition. Also, one clinical psychologist with expertise in FAPDs is a voting member in the GDG. A final consensus list of treatment options is translated into ‘patient, intervention, comparison, outcome’ format options. Prospective agreement on the magnitude of health benefits or harms categories was reached through a Delphi process among the GDG to support grading of the literature. There will be a detailed technical evidence review with randomised controlled trial data that will be judged for risk of bias with the Cochrane tool. Recommendations are preferably based on GRADE but could also be best practice statements following the available evidence. A full Delphi process will be used to make recommendations using online response systems. This set of procedures has been approved by all members of the GDG

Symmetry Reduction for STE Model Checking Using Structured Models

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