A domain-specific language approach to hybrid cps modelling

The recent advent of cyber-physical systems (CPSs) in end-user applications extends the need for sophisticated model creation, simulation and system verification to new application areas. CPSs such as smart homes seamlessly integrate technology into every-day life, rendering their safety and correctness paramount. The intricacy of these systems’ modelling stems from the merging of two opposing views: While flows of physical energy are mostly described using mathematical methods such as differential equations, engineered applications are usually best expressed using discrete formalisms. This thesis describes the creation of the Continuous REactive SysTems language (CREST), a domain-specific language (DSL) dedicated to the combined modelling of physical resource flows and engineered behaviour. The language coherently merges architectural concerns, reactive dataflow and non-determinism. Its Python implementation allows convenient system modelling and supports advanced concerns such as the simulation and formal verification of hybrid systems based on sound theoretical foundations

Guidelines for the development of a GUI-regression-testing-framework for SCADA applications using the example of the JCOP-Framework as used by the CERN LHC and its experiments

The aim of this bachelor thesis is to give a theoretical guidance in developing and in- tegrating a GUI-test-framework. Its content is derived from the experience gained during the development of the „Emu“-framework, which is used by CERN for the testing of the user-interface of the „JCOP-Framework“, which provides „an integrated set of guidelines and software tools which is used by Developers of a Control System to develop their part of a Con- trol System application.“ The lessons learned from this project are collected in this thesis, so that others can draw conclusions and use them for creation of their own testing frameworks

1st Developers@CERN Forum

I would like to present the concept of automated test case generation. I work on it as part of my PhD and I think it would be interesting also for other people. It is also the topic of a workshop paper that I am introducing in Paris. (abstract below) Please note that the talk itself would be more general and not about the specifics of my PhD, but about the broad field of Automated Test Case Generation. I would introduce the main approaches (combinatorial testing, symbolic execution, adaptive random testing) and their advantages and problems. (oracle problem, combinatorial explosion, ...) Abstract of the paper: Over the last decade code-based test case generation techniques such as combinatorial testing or dynamic symbolic execution have seen growing research popularity. Most algorithms and tool implementations are based on finding assignments for input parameter values in order to maximise the execution branch coverage. Only few of them consider dependencies from outside the Code Under Test’s scope such as global variables, database values and subroutine calls as influences to the execution path. In order to fully test all possible scenarios these dependencies have to be taken into account for the test input generation. This paper introduces ITEC, a tool for automated test case generation to support execution environment resilience in large-scaled, complex systems. One of ITEC’s corner stones is a technique called semi-purification, a source code transformation technique to overcome limitations of existing tools and to set up the required system state for software testing

CREST - A DSL for Reactive Cyber-Physical Systems

This article presents CREST, a novel domain-specific language for the modelling of cyber-physical systems. CREST is designed for the simple and clear modelling, simulation and verification of small-scale systems such as home and office automation, smart gardening systems and similar. The language is designed to model the flow of resources throughout the system. It features synchronous system evolution and reactive behaviour. CREST's formal semantics allow real-valued time advances and the modelling of timed system evolution. The continuous time concept permits the precise simulation of future system behaviour by automatically calculating next transition times. We present CREST in a practical manner, and elaborate on the Python-based DSL implementation and simulator

ML4CREST: Machine Learning for CPS Models

Models of small CPS and IoT applications often use approximated values that describe physical system behaviour. Physical resources, such as electricity consumption and heating power, have to be estimated, since many off-the-shelf components lack the required descriptions. Controllers which are based on these approximations can hence use imprecise models, perform misleading simulation, and cause damaged systems and financial loss. In this paper we present ML4CREST, a machine learning approach to automatically calibrate models using sensor measurements. We show that our approach is well-suited for the calibration of the flow rates within an automated watering system, which allows precise simulation and prevents spillage

Towards Language Independent Dynamic Symbolic Execution

Symbolic execution is well-known for its capability to produce high-coverage test suites for software source code. So far, most tools are created to support a specific language. This paper elaborates on performing language independent symbolic execution. We describe the use of one approach to perform dynamic symbolic execution using translation of a proprietary language and show the results of the tool execution on a real-life codebase

Petri Sport: A Sport for Petri Netters

Petri nets are a family of formalisms dedicated to the representation of concurrent systems. Their strength is the compact modeling of complex behaviors using very simple rules. Despite this simplicity, many teachers observe that students often require a lot of exposure and numerous exercises to truly understand the semantics of Petri nets. In order to speed up this learning process and provide a different attack angle, we propose Petri sport, a fun game based upon the Petri net formalism. In Petri sport, players aim to gather points by moving across a Petri net-shaped playing field and “firing” transitions. A clock-based play style supports a structured game advance while at the same time it encourages players to move fast. As the playing field is shaped like a Petri net, it is possible to challenge a player's movement speed, intellectual capabilities, as well as team coordination and communication. The difficulty level of Petri sport is based on the choice of playing field. This allows for adaptation in order to best fit the competitors' age, experience and/or physical fitness level