Spreadsheet-based Configuration of Families of Real-Time Specifications

Model checking real-time systems is complex, and requires a careful trade-off between including enough detail to be useful and not too much detail to avoid state explosion. This work exploits variability of the formal model being analysed and the requirements being checked, to facilitate the model-checking of variations of real-time specifications. This work results from the collaboration between academics and Alstom, a railway company with a concrete use-case, in the context of the VALU3S European project. The configuration of the variability of the formal specifications is described in MS Excel spreadsheets with a particular structure, making it easy to use also by developers. These spreadsheets are processed automatically by our prototype tool that generates instances and runs the model checker. We propose the extension of our previous work by exploiting analysis over valid combination of features, while preserving the simplicity of a spreadsheet-based interface with the model checker.Comment: In Proceedings TiCSA 2023, arXiv:2310.1872

Analysing oscillatory trends of discrete-state stochastic processes through HASL statistical model checking

The application of formal methods to the analysis of stochastic oscillators has been at the focus of several research works in recent times. In this paper we provide insights on the application of an expressive temporal logic formalism, namely the Hybrid Automata Stochastic Logic (HASL), to that issue. We show how one can take advantage of the expressive power of the HASL logic to define and assess relevant characteristics of (stochastic) oscillators

A multi-decade record of high quality fCO2 data in version 3 of the Surface Ocean CO2 Atlas (SOCAT)

The Surface Ocean CO2 Atlas (SOCAT) is a synthesis of quality-controlled fCO2 (fugacity of carbon dioxide) values for the global surface oceans and coastal seas with regular updates. Version 3 of SOCAT has 14.7 million fCO2 values from 3646 data sets covering the years 1957 to 2014. This latest version has an additional 4.6 million fCO2 values relative to version 2 and extends the record from 2011 to 2014. Version 3 also significantly increases the data availability for 2005 to 2013. SOCAT has an average of approximately 1.2 million surface water fCO2 values per year for the years 2006 to 2012. Quality and documentation of the data has improved. A new feature is the data set quality control (QC) flag of E for data from alternative sensors and platforms. The accuracy of surface water fCO2 has been defined for all data set QC flags. Automated range checking has been carried out for all data sets during their upload into SOCAT. The upgrade of the interactive Data Set Viewer (previously known as the Cruise Data Viewer) allows better interrogation of the SOCAT data collection and rapid creation of high-quality figures for scientific presentations. Automated data upload has been launched for version 4 and will enable more frequent SOCAT releases in the future. High-profile scientific applications of SOCAT include quantification of the ocean sink for atmospheric carbon dioxide and its long-term variation, detection of ocean acidification, as well as evaluation of coupled-climate and ocean-only biogeochemical models. Users of SOCAT data products are urged to acknowledge the contribution of data providers, as stated in the SOCAT Fair Data Use Statement. This ESSD (Earth System Science Data) “living data” publication documents the methods and data sets used for the assembly of this new version of the SOCAT data collection and compares these with those used for earlier versions of the data collection (Pfeil et al., 2013; Sabine et al., 2013; Bakker et al., 2014). Individual data set files, included in the synthesis product, can be downloaded here: doi:10.1594/PANGAEA.849770. The gridded products are available here: doi:10.3334/CDIAC/OTG.SOCAT_V3_GRID

Loupe: Verifying Publish-Subscribe Architectures with a Magnifying Lens

CONE

220504

Motor controllers, such as the ones used in signalling systems, include critical embedded software. Alstom is a company that produces such embedded systems, which must follow complex certification processes that require formal modelling and analysis. The formal analysis of these real-time systems have to balance between including enough details to be useful and abstracting away enough details to be verifiable. This paper describes our work in the context of the European VALU3S project to integrate the analysis of such systems with the Uppaal model checker during the development cycle, involving both developers from Alstom and academic partners. We use special Excel tables to configure the underlying Uppaal models and requirements, bridging these two stakeholders. We follow Software Product Line Engineering principles, e.g., allowing features to be turned on and off and periodicities to be changed, and verify different properties for each of such configuration. We automate the instantiation and verification in Uppaal of a set of selected configurations via an open-source prototype tool named Uppex.This work was partially supported by National Funds through FCT/MCTES (Portuguese Foundation for Science and Technology), within the CISTER Research Unit (UIDP/UIDB/04234/2020); also by the Norte Portugal Regional Operational Programme (NORTE 2020) under the Portugal 2020 Partnership Agreement, through the European Regional Development Fund (ERDF) and also by national funds through the FCT, within project NORTE-01-0145-FEDER-028550 (REASSURE); also by COMPETE 2020 under the PT2020 Partnership Agreement, through ERDF, and by national funds through the FCT, within project POCI-01-0145-FEDER- 029946 (DaVinci); also by FCT within project ECSEL/0016/2019 and from the ECSEL Joint Undertaking (JU) under grant agreement No 876852 (VALU3S). The JU receives support from the European Union's Horizon 2020 research and innovation programme and Austria, Czech Republic, Germany, Ireland, Italy, Portugal, Spain, Sweden, Turkey.N/

Developing a distributed electronic health-record store for India

The DIGHT project is addressing the problem of building a scalable and highly available information store for the Electronic Health Records (EHRs) of the over one billion citizens of India

Type Safe Extensible Programming

Software products evolve over time. Sometimes they evolve by adding new features, and sometimes by either fixing bugs or replacing outdated implementations with new ones. When software engineers fail to anticipate such evolution during development, they will eventually be forced to re-architect or re-build from scratch. Therefore, it has been common practice to prepare for changes so that software products are extensible over their lifetimes. However, making software extensible is challenging because it is difficult to anticipate successive changes and to provide adequate abstraction mechanisms over potential changes. Such extensibility mechanisms, furthermore, should not compromise any existing functionality during extension. Software engineers would benefit from a tool that provides a way to add extensions in a reliable way. It is natural to expect programming languages to serve this role. Extensible programming is one effort to address these issues. In this thesis, we present type safe extensible programming using the MLPolyR language. MLPolyR is an ML-like functional language whose type system provides type-safe extensibility mechanisms at several levels. After presenting the language, we will show how these extensibility mechanisms can be put to good use in the context of product line engineering. Product line engineering is an emerging software engineering paradigm that aims to manage variations, which originate from successive changes in software.Comment: PhD Thesis submitted October, 200