Ph. D. Project
Title:
COSPESIM - Co-simulation system model co-specification
Dates:
2021/10/01 - 2024/09/30
Supervisor(s): 
Other supervisor(s):
Pr CHEVRIER Vincent (vincent.chevrier@univ-lorraine.fr)
Description:
The ISET department, has been developing for several years research activities in the field of Complex Systems Engineering (Phd Evrot D. (2008), Dobre D. (2010), Bouffaron F. (2016), Wu Q. (2020). These works has focused on the formalization of System Engineering practices (Model-Based System Engineering (MBSE)) with the objective of founding the processes, models and methods of System Engineering (SE), in order to facilitate their adoption and operational implementation in complex and evolving industrial contexts.
The SIMBIOT team at LORIA is working on multi-modeling and co-simulation to represent a complex system as a set of heterogeneous subsystems interacting Phd Siebert J. (2011), Camus B. (2011), Vaubourg J. (2017), Paris T. (2019) and two in progress). It develops and maintains the MECSYCO co-simulation platform, allowing the rigorous integration of different models and their simulators. This software is used for various applications in the energy field (Vaubourg et al. 2015 with EDF R&D) or teaching (Paris et al. 2019).
Thus, the two teams share their respective expertise to propose a method for designing a system model of co-simulation from a system co-specification.
In SE, the problems encountered by industry are the lack of a global system vision, due to a fragmented vision (knowledge silos) of the systems to be developed according to the disciplinary fields concerned, as well as the lack of agility of the processes which does not encourage their adoption. These problems lead to time and cost overruns in SE projects as well as the failure to meet customer requirements.
To address these problems (lack of global vision, lack of process agility), the work developed by ISET has focused on the formalization of the specification process (D. Dobre 2010) involving the different engineering actors (system and disciplines), then on a collaboratively built system specification and its execution (executable co-specification) (F. Bouffaron 2016). In a second step, in order to act on the adoption of an MBSE approach in companies, the thesis of Q. Wu's thesis focuses on the capitalization of engineering know-how in the form of modeling patterns (library creation, identification, pattern research) and on the evaluation of the maturity of the reuse process. In this thesis we wish to extend the work on model-based executable system co-specification using co-simulation. The main idea defended is to have from the beginning and throughout the engineering process an executable model of the specification, from a system vision to the detailed design levels of the architectures (business). This model would allow, in an agile way, at each level of system abstraction, by successive refinements, to have a unique, global and shareable vision of the system to be made and to evaluate the specification under development : V&V and analysis. Beyond engineering, this model would enable the approach towards Integration to be extended, by verifying and validating the business developments of components, modules and software using general mechanisms of the "X in the loop" type (Model, Hardware, Software).
In the community, a new skill has emerged to meet these architecture and model integration needs: Simulation Architect (F. Retho 2015 and G. Sirin 2015), acting as an interface between the system architect (AS guaranteeing the overall vision) and business experts. His role consists, from AS requests, of specifying an intention model for the business experts, returning a realization model to be integrated to build a system (co-)simulation.
From the point of view of co-simulation, recent work at LORIA (Paris 2019) makes it possible to incrementally integrate simulators to build the co-simulation of a target system (digital twin). The approach is bottom-up, by composing existing software models. However, in the case of complex systems, this integrative approach reaches its limits and does not guarantee consistency and validation. It is therefore a question of having a method for building a co-simulation model of a system (existing or under development) that guarantees the coherence and validity of the co-simulation model.
The topics to be adressed for this purpose concern :
- The design of the architecture of the co-simulation model from the system model according to the level of progress of the project (passage from system artifacts to the specification of the elements of the co-simulation model, definition of the interactions between system model and simulation business models, evaluation/verification of system properties at each step).
- The extension of system co-specification mechanisms (Bouffaron 2016) to the construction of a co-simulable system model (interaction mechanisms between AS, simulation/model architect and business experts);
- The definition of the specification process of an intent model, by the simulation architect;
- The validation of contributions on the APHEEN case study for the co-simulation of the thermal behaviors of a building for the optimization of energy consumption.

The main results consist in a method for designing a co-simulation system model based on a system co-specification, ensuring consistency from the system level to the most detailed levels of architectural design (trades).
Other contributions are expected:
- On an application level, thanks to the collaboration with APHEEN, a prototype will be built with concrete requirements and components that can be validated against the real system.
- On a societal level, the energy renovation of existing buildings is a crucial issue. This thesis will bring methodological elements allowing the construction of the digital twin of a building.
- On a software level, the Mecsyco platform distributed under AGP license will be enriched with functionalities associated with the system engineering
Keywords:
System Engineering, Co-simulation, Co-Specification, Digital Twin, Thermal Models
Conditions:
Duration: 3 years
Employer :
Location : CRAN/LORIA
Salary :
Expected profile: Master in Complex Systems Engineering; Telecom Nancy, Master in Computer Science
Department(s): 
Eco-Technic systems engineering
Funds:
Application for FCH and Grand Est Region funding