Improving simulation specification with MBSE for better simulation validation and reuse

International audienceA simulation can be a complex architecture of simulation models, simulation tools, and computing hardware. However, its development often relies on informal procedures and can begin without a clear, complete, and formal definition of the simulation needs. Simulation traceability is then compromised, which prevents from easily validating whether a simulation meets the needs, or understanding the purpose of a simulation model that can be reused. This paper proposes an approach to improve the definition of simulation needs using Model-Based Systems Engineering. Based on the semi-automatic processing of a system architecture, it presents a new method to formulate a so-called “simulation request” which covers (1) the part of the system to be simulated; (2) the objective of the simulation; (3) the simulation quality, cost, and delivery; (4) the test scenarios; (5) the data for simulation calibration and validation; and (6) the verification and validation of the simulation. All the tooling required for the formulation of the simulation request were prototyped in a SysML editor, with machine learning capabilities for the choice of test scenarios. The method and tooling were tested for the case of an autonomous car passing under traffic lights

A tooled methodology for the system architect's needs in simulation with autonomous driving application

International audienceModel Based Systems Engineering (MBSE) is a promising solution to formalize and communicate information about the design of complex systems, in particular for the automotive industry which faces new challenges associated to autonomous driving. Numerical simulation is commonly used to support the design of these complex systems, but the possible relations with MBSE should be further investigated. This work, conducted with academic and industrial partners at the research institute IRT SystemX, aims at further bridging the gap between system architecture and numerical simulation. An industrial design problem related to the design of an autonomous vehicle passing traffic lights is used to validate and illustrate new methods and tools based on SysML. Their aim is to: 1) guide the formulation of a question requiring simulation, called solicitation, by the system architect 2) guide the design of a simulation architecture by the simulation architect with a special focus on the consistency with the system. A Java plugin was developed in the SysML editor Papyrus for the solicitation, and a SysML metamodel was defined for the simulation architecture. The solicitation associated to the industrial design problem is answered by a multiobjective optimization of the vehicle's cost and electrical consumption using a co-simulation between the tools Simulink and Amesim

A Tph2GFP Reporter Stem Cell Line To Model in Vitro and in Vivo Serotonergic Neuron Development and Function

Modeling biological systems in vitro has contributed to clarify complex mechanisms in simplified and controlled experimental conditions. Mouse embryonic stem (mES) cells can be successfully differentiated towards specific neuronal cell fates, thus representing an attractive tool to dissect, in vitro, mechanisms that underlie complex neuronal features. In this study, we generated and characterized a reporter mES cell line, called Tph2(GFP), in which the vital reporter GFP replaces the Tryptophan hydroxylase 2 (Tph2) gene. Tph2(GFP) mES cells selectively express GFP upon in vitro differentiation towards the serotonergic fate, they synthetize serotonin, possess excitable membranes and show the typical morphological, morphometrical and molecular features of in vivo serotonergic neurons. Thanks to the vital reporter GFP we highlighted by time-lapse video-microscopy several dynamic processes such as cell migration and axonal outgrowth in living cultures. Finally, we demonstrated that pre-differentiated Tph2(GFP) cells are able to terminally differentiate, integrate and innervate the host brain when grafted in vivo. On the whole, the present study introduces the Tph2(GFP) mES cell line as a useful tool allowing accurate developmental and dynamic studies, and represents a reliable platform for the study of serotonergic neurons in health and disease

A <i>Tph2</i>^<i>GFP</i> Reporter Stem Cell Line To Model <i>in Vitro</i> and <i>in Vivo</i> Serotonergic Neuron Development and Function

Modeling biological systems <i>in vitro</i> has contributed to clarification of complex mechanisms in simplified and controlled experimental conditions. Mouse embryonic stem (mES) cells can be successfully differentiated toward specific neuronal cell fates, thus representing an attractive tool to dissect, <i>in vitro</i>, mechanisms that underlie complex neuronal features. In this study, we generated and characterized a reporter mES cell line, called <i>Tph2</i>^<i>GFP</i>, in which the vital reporter GFP replaces the <i>tryptophan hydroxylase 2</i> (<i>Tph2</i>) gene. <i>Tph2</i>^<i>GFP</i> mES cells selectively express GFP upon <i>in vitro</i> differentiation toward the serotonergic fate, they synthesize serotonin, possess excitable membranes, and show the typical morphological, morphometrical, and molecular features of <i>in vivo</i> serotonergic neurons. Thanks to the vital reporter GFP, we highlighted by time-lapse video microscopy several dynamic processes such as cell migration and axonal outgrowth in living cultures. Finally, we demonstrated that predifferentiated <i>Tph2</i>^<i>GFP</i> cells are able to terminally differentiate, integrate, and innervate the host brain when grafted <i>in vivo</i>. On the whole, the present study introduces the <i>Tph2</i>^<i>GFP</i> mES cell line as a useful tool allowing accurate developmental and dynamic studies and representing a reliable platform for the study of serotonergic neurons in health and disease

A <i>Tph2</i>^<i>GFP</i> Reporter Stem Cell Line To Model <i>in Vitro</i> and <i>in Vivo</i> Serotonergic Neuron Development and Function

Modeling biological systems <i>in vitro</i> has contributed to clarification of complex mechanisms in simplified and controlled experimental conditions. Mouse embryonic stem (mES) cells can be successfully differentiated toward specific neuronal cell fates, thus representing an attractive tool to dissect, <i>in vitro</i>, mechanisms that underlie complex neuronal features. In this study, we generated and characterized a reporter mES cell line, called <i>Tph2</i>^<i>GFP</i>, in which the vital reporter GFP replaces the <i>tryptophan hydroxylase 2</i> (<i>Tph2</i>) gene. <i>Tph2</i>^<i>GFP</i> mES cells selectively express GFP upon <i>in vitro</i> differentiation toward the serotonergic fate, they synthesize serotonin, possess excitable membranes, and show the typical morphological, morphometrical, and molecular features of <i>in vivo</i> serotonergic neurons. Thanks to the vital reporter GFP, we highlighted by time-lapse video microscopy several dynamic processes such as cell migration and axonal outgrowth in living cultures. Finally, we demonstrated that predifferentiated <i>Tph2</i>^<i>GFP</i> cells are able to terminally differentiate, integrate, and innervate the host brain when grafted <i>in vivo</i>. On the whole, the present study introduces the <i>Tph2</i>^<i>GFP</i> mES cell line as a useful tool allowing accurate developmental and dynamic studies and representing a reliable platform for the study of serotonergic neurons in health and disease