Farouk Belkadi

Mohamed Anis Dhuieb

José Vicente Aguado

Florent Laroche

Alain Bernard

Francisco Chinesta

Intelligent assistant system as a context-aware decision-making support for the workers of the future

Keywords: Context-awareness, Decision-aid system, Factory of the future, Knowledge management, PGD, PerioSystem, 92130

de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

Introduction

In their recent research review, [START_REF] Esmaeilian | The evolution and future of manufacturing: A review[END_REF] highlights more than 40 technological, societal and informational pillars for the factory of the future. Among these elements, information and communication technologies and knowledge asset take a great interest in the new strategies and Farouk Belkadi 1 *, Mohamed Anis Dhuieb 2 , José Vicente Aguado 3 , Florent Laroche 1 , Alain Bernard 1 , Francisco Chinesta 3

1 Laboratory of Digital Sciences of Nantes, LS2N -UMR CNRS 6004, Ecole Centrale de Nantes, France 2 3 offer high potential of innovation [Wu et al., 2017]. This is because human capital is the driving force for production efficiency and optimization [START_REF] Mavrikios | A web-based platform for collaborative product design, review and evaluation[END_REF]]. However, although their role is indisputable, the actors of the factory are capable of making mistakes that, no matter what their origin, have a direct influence on the cost of non-quality (CNQ) and delays [START_REF] Schiffauerova | A review of research on cost of quality models and best practices[END_REF]. Some studies have demonstrated that human-caused CNQ is due to three main reasons: lack of appropriate guidelines, gaps in training, and the unavailability of documentation in production lines [START_REF] Benhabib | Les coûts de non-qualité[END_REF]. Furthermore, the heterogeneity of data and information makes their integration and management very complex [START_REF] Zhong | Big Data for supply chain management in the service and manufacturing sectors: Challenges, opportunities, and future perspectives[END_REF]. Managers aiming to face today's competitiveness are continuously seeking to help their employees to efficiently accomplish their jobs.

This goalcould be achievedby promoting a human-centered visions and roadmaps as key pillars of the factory of the future (FoF) [START_REF] Longo | Smart operators in industry 4.0: A human-centered approach to enhance operators' capabilities and competencies within the new smart factory context[END_REF].

In this context, the concept of "Digital Factory Assistant" (DFA) is proposed under the ARTUR (in French: AtelieR du fuTUR, translated as shop-floor of the future in English) project as a framework for intensive knowledge reuse dedicated to assist factory workers in their daily activities. The aim is also to improve the operational process efficiency through a set of decision-making support for problem solving and reaction against various events and operational constraints.

Indeed, to deal with different working situations, actors have to be aware of important elements in the situation and to interpret it correctly according to their task of interest [START_REF] Hasan | Integrating safety into the design process: elements and concepts relative to the working situation[END_REF].

Being constantly aware of all these elements is a difficult task for the workers and may lead to a cognitive overload. Based on contextual knowledge reuse, high-speed simulation and advanced visualization techniques, the aim of the DFA framework is to provide proactive support for different manufacturing tasks. As an extension of classical decisions support systems that mainly focus on the delivery of key indicators and risk notifications, the proposed framework aims to centralize the knowledge asset in the factory and enables each actor to access the useful knowledge according to his/her working situation and real operational need. That said,the decision-making support built under the proposed framework will considerthe user's profile by formatting the appropriate information in a consistent way so as to allow him well understanding and easier use of the available knowledge [Laroche et al., 2012;[START_REF] Dhuieb | Digital Factory Assistant: Conceptual Framework and Research Propositions[END_REF].

The remaining of the paper is organized as follow. Section 2 discusses the main innovations within the paradigm of factory of the future. A state-of-the-art of different knowledge based and decision-making support systems used in the manufacturing field is given. The choice of these systems was based on two main criteria: the application scope and the consideration of the concept of context as enabler of the systems. The motivations of the proposed intelligent assistant system are explained at the end of this section while the characteristics of this framework are detailed in section 4 from conceptual and technical points of view. Section 5 concentrates on the problem of multiphysics simulation as key assistance functionality proposed by the Framework. This aspect is illustrated through an implementation scenario allowing users to access contextually to the simulation models in real time condition. In section 6, the advantages and limits of the proposed system are discussed based on feedback from first application in industrial context and a comparison with some existing tools. Conclusion and perspectives of future developments are given at the end.

Motivations: Towards a new generation of assistant systems in factory

Visions of the factory of the future

Complementary visions contribute to the initiative of the factory of the future [START_REF] Göleç | A relationship framework and application in between strategy and operational plans for manufacturing industry[END_REF].

According to [START_REF] Westkämper | Towards the Re-Industrialization of Europe[END_REF], the factory of the future requires holistic production systems with learning capabilities integrated into the entire product lifecycle, from the design and initial configurations to after-sales services. In particular, the smart factory aims to enhance the control and the optimization of factory processes based on advanced ICT tools [START_REF] Lucke | Smart factory-a step towards the next generation of manufacturing[END_REF]. For instance, the vision for a smart factory developed in the work of [START_REF] Zuehlke | SmartFactory Towards a factory-of-things[END_REF] aims to build the concept of the "Factory of Things" where the factory implements intelligent objects interacting together to exchange information about their states. This vision is inspired by the "Internet of Things" concept developed in computer science [START_REF] Lee | Framework and development of fault detection classification using IoT device and cloud environment[END_REF].

The German thoughts about the factory of the future are expressed in the concept of industry 4.0 [START_REF] Kagermann | Recommendations for Implementing the Strategic Initiative INDUSTRIE 4.0: Securing the Future of German Manufacturing Industry[END_REF]. This concept encloses technologies and industrial processes allowing all the physical and virtual actors of the production system to interact in the same environment.

According to this vision, the next industrial revolution will be distinguished by the generalization of sensors and intelligent agents with the aim of communicating with other machines, products, processes, humans, etc. The main objectives are to rapidly detect any production variation, anticipate the dysfunction and accelerate the research for new solutions and alternatives.

The importance of giving more emphasis to the role of the human being as a key driver for better factory performance has been pointed out by many visions and roadmaps about the factory of the future. Mainly, [START_REF] Westkämper | Towards the Re-Industrialization of Europe[END_REF] discussed the next human-centered production systems and how the human being will work jointly with digital objects in the factory. Knowledge engineering tools and methods are one of the key enablers supporting this issue [START_REF] Quintana-Amate | A new knowledge sourcing framework for knowledge-based engineering: An aerospace industry case study[END_REF].

Emerging ICT trends for future manufacturing systems

The importance of information systems (IS) in industry has been highlighted from the last three decades and several propositions have been made along this period [START_REF] Collins | Manufacturing Information Systems Issues: Software Architectures[END_REF]. In [START_REF] Toro | Knowledge based industrial maintenance using portable devices and augmented reality[END_REF] for example, a framework were developed for the exploitation of embedded knowledge in industrial maintenance. maintenance agent may encounter in real life. In another study, decision support system architecture was proposed by [START_REF] Klein | A simulation-based decision support system: The example of a furniture manufacturer[END_REF] in order to improve product flow control. The novelty in their work was to continuously feed the decision support system by Kanban cards that provide additional shop-floor information. The aim was to give the decision-maker a consistent view of the shop-floor.

While in [START_REF] Kong | Development of an intelligent decision support system for metal forming industry[END_REF], an intelligent decision support system was developed to support the task allocation and reallocation, local queue management and production resource management in the metal forming process.

The CARMMI framework outlined in the work of [Espindola et al., 2013] provides a support to operators during maintenance tasks through mixed reality. The presented framework allows the acquisition and presentation of different CAx data with the aim of predicting breakdowns that may occur in industrial equipment. [START_REF] Kwon | ubiDSS: a framework of multi-agent based proactive decision support system with context-awareness[END_REF] has developed a framework called ubiDSS. ubiDSS is a framework of multi-agent and context-aware-based proactive decision support system. The architecture of this framework is composed of a number of subsystems: context subsystem, dialogue subsystem, knowledge subsystem, model management subsystem, and a database management subsystem. Even though the application field of the ubiDSS system is not applied in the manufacturing domain, it gives very interesting lessons on the interactions between the components of such a framework.

Recently, the new generation of IS embeds intelligence and communication features to provide assistance tailored to specific business process such as for maintenance and machine configuration [START_REF] Ruschel | Industrial maintenance decision-making: A systematic literature review[END_REF]. As explained by [START_REF] Satyanarayanan | Pervasive computing: Vision and challenges[END_REF], our Society has moved progressively from a Distributed System to pervasive and ambient computing [START_REF] Syvanen | Supporting Pervasive Learning Environments: Adaptability and Context Awareness in Mobile Learning[END_REF]. The first two states have been observed but the last and third one is coming [START_REF] Cliquet | Méthode d'innovation à l'ère du Web 2.0[END_REF] (see Figure 1).

Distributed systems allow remote communication and access to shared information inside wide networks while preserving security and data availability issues via encryption, authentication and backup technologies. Mobile systems propose advance communication facilities that ensure continuity of services independent from geographical location. To enhance their efficiency, these tools are based on limited resources and offer summarized interfaces to be adapted to various environments. Ubiquitous systems are the category of systems that take in consideration the context of user through some measurements and personalization of profile [START_REF] Lyytinen | Issues and challenges in ubiquitous computing[END_REF]. This concept is introduced in 1991 by Weiser [START_REF] Weiser | The computer for the 21st century[END_REF] to describe a computer vision which provides assistance without anyone noticing its presence. Additional technologies like virtual and augmented reality [START_REF] Nee | Augmented reality applications in design and manufacturing[END_REF] are now an emerging field in industry and contribute to its evolution. The aim is to enhance the real life sensation of the user when interacting with the decision system. To sum up, many systems and frameworks applied to different working environments in the factory were found. Most of the research works are oriented towards specific applications. Except for [START_REF] Kong | Development of an intelligent decision support system for metal forming industry[END_REF], fewer research works has tried to assist factory stakeholders at machine level where the information is less available but essential in the achievement of manufacturing tasks.

Looking to the actual maturity on the usage of information and communication technologies, even in the "ordinary life", it is assumed that the factory of the future must follow this tendency and demonstrate a great implication on the adoption of such technologies.

Evolution of Decision Support Systems

Decision Support Systems (DSS) are kind of information systems provided with a high capability of reasoning to provide their users with a set of appropriate information [START_REF] Schönberger | Decision support systems and the coordination of supply consortium partners[END_REF].

In [START_REF] Shim | Past, present, and future of decision support technology[END_REF], DSS are defined as "a set of computer technology solutions that can be used to support complex decision making and problem solving". Even though multiple definitions of DSS can be found in literature, they share a common vision: DSS attempt to automate several tasks of the decision making process [START_REF] Büyüközkan | A novel fuzzy multi-criteria decision framework for sustainable supplier selection with incomplete information[END_REF] in order to provide users with a set of possible solutions regarding his/her problem. In final, the decision is selected, accepted or modified or refused by the Human.

Since their appearance, DSS has evolved in a significant way thanks to the side-by-side evolution made in information and communication technologies. This evolution has resulted in the appearance of a web-based technologies [START_REF] Boreisha | Web-based decision support systems as knowledge repositories for knowledge management systems[END_REF], Mobile solutions [START_REF] Wen | A mobile knowledge management decision support system for automatically conducting an electronic business[END_REF], and the ubiquitous DSS [START_REF] Kwon | UbiDSS: a proactive intelligent decision support system as an expert system deploying ubiquitous computing technologies[END_REF]. awareness [START_REF] Dhuieb | Context-awareness: a key enabler for ubiquitous access to manufacturing knowledge[END_REF][START_REF] Carneiro | A Context-aware Model to Support Ubiquitous Group Decision Making[END_REF] takes an important place in order to anticipate the user's needs in a particular situation and act proactively to provide appropriate assistance. [START_REF] Kwon | UbiDSS: a proactive intelligent decision support system as an expert system deploying ubiquitous computing technologies[END_REF].

Context awareness provide a clearer understanding of the way experts integrate knowledge during problem solving, and thus provide common grounds for decision-making and knowledge sharing [Anya et al., 2012]. Thanks to these capacities, a context-aware decision support system utilizes contextual information in the problem solving process to provide personalized service with minimum of explicit interaction between human and computer [START_REF] Chen | Integrating context-aware computing in decision support system[END_REF]. It provides people by accurate information on their environment and assists experts making plans and monitoring their daily activities [START_REF] Fadzillah | Context awareness monitoring model for smart office environment[END_REF], [START_REF] Ngai | Design and development of an intelligent context-aware decision support system for real-time monitoring of container terminal operations[END_REF].

Synthesis

The main idea of ubiquitous computing based DSS is to apply the vision of Weiser [START_REF] Weiser | The computer for the 21st century[END_REF] with the aim of ensuring a higher level of information availability and proactivity. Embedding ubiquitous facilities can resolve the problem of user workload when manipulating several information systems and requiring real time assistance. However, even this concept is old, it is still an interesting scientific challenge that until now has not been sufficiently exploited by the industrial engineering research communities. Particularly, the usage of this kind of systems is limited because of the need of advanced technologies and the manipulation of large amount of data. Actually, recent developments on big data collection and analysis as well as interoperability with information systems make the challenge reachable. This constitutes the first motivation of this research work: how a smart combination of recent technologies can contribute to the improvement of business processes? The second motivation is leaded by the application domain: industrial environment especially dedicated to the workers who generally are not familiar with such kind of applications and require more consideration of their level of expertise.

As a synthesis of the state of the art, the ubiquitous computing paradigm came with interesting concepts that the industrial community and the visions of the factory of the future can benefit from.

Table 1 compares the proposed digital factory assistant with other systems and frameworks cited in the second section. The comparison is based on different points of view.

 Situation perception: indicate if the system proposes some connections to sensors, information systems and other facilities to real time capturing of new events in the situation.

 User assistance: through real time notifications and warnings or offline procedures and reports to prevent risks of task failure or security problems.

 Collaboration facilities: indicates if the system is able to support information sharing and situation awareness as well as coordination rules.

 MMI (Man Machine Interaction): or how the system support Knowledge restitution and presentation, which is a very important aspect that affect the efficiency of any DSS.

 Contextual access: indicates if the system allows users accessing to content and functionalities based on their current objectives and status of their activities.

 Legacy tools interoperability: does the system use some connections to legacy tools to extract knowledge, perform computing or realize some offline simulations.

 Application domain: gives information about the genericity level of the solution depending on the variety of business domains.

ARTUR Platform: Functional architecture and related foundations

Looking at the actual industrial problematics and considering the recommendations of the state of the art, this section aims to set up the key elements of the proposed decision making platform by representing the functional architecture and describing the main scientific foundations behind the proposed functions.

Functional architecture

Analyzing and managing requirements of heterogeneous stakeholders is a key step to guarantee successful software project [START_REF] Violante | An integrated approach to support the Requirement Management (RM) tool customization for a collaborative scenario[END_REF]. The analysis of the current needs of the operational actors in a factory points out three fundamental requirements to be respected by the assistant system: the multi-scale knowledge structuring approach, the ubiquitous knowledge access and the real time assistance. The first feature is because the expertise level is different from one worker to another and it is needed to adapt the knowledge restitution according to the user profile.

The second feature highlights the fact that efficient decision making assistant should take in consideration the problem to resolve but also the current working situation of the decider that can impact his actions. Finally, real time assistance because that the worker is at the operational level face to the machine and need to react rapidly to some events. Real time simulation is preferred for this topic. Other aspects related to the virtual engineering based assistance in the ARTUR project are beyond the scope of this paper. However, some illustrations on how virtual engineering tools can be linked to PLM systems through the DFA framework are explained in [START_REF] Dhuieb | Thinking factory for the future: from PLM to augmented reality[END_REF].

The aim of the DFA system is to provide the worker at the production line by a set of useful information at the right moment when he//she is facing the machine. Concretely, the core functionalities are the followings:

 Providing the right formal procedures for the configuration of the machine and the selection of the process parameters.

 Capitalizing and sharing the best practices as applied usually by the experts when resolving some operational but redundant problems.

 Real time simulation to assist the user analyzing the effect of different machine/process configurations on the form of the resulted product.

 Knowledge transformation and adaptation for optimal restitution according to the level of expertise of the workers and his/her context of work.

That said, the development of these functionalities requires solid scientific foundations but pragmatics from an industrial point of view. The next sections describe this kernel aspect.

Multi-scale knowledge structuring approach

In this work, we propose an approach in order to structure the knowledge set into multiple scales as a conceptual foundations supporting efficient knowledge restitution. The idea of expertise breakdown into different levels can be found in the model of [START_REF] Dreyfus | Mind over machine[END_REF] who proposes to organize the skills that anyone can acquire into five stages: novice, advanced beginner, competent, proficient and expert.

In this work, three knowledge restitution levels are distinguished. Each one translates a completeness level of an activity domain in the factory. With respect to the multi-scale structuring hypothesis, the knowledge base can be organized in three completeness levels:

. It is intended to store and to formalize the same knowledge within different representation. The knowledge K i is a triplet K i =<P i |Pr i |R i > where P i , Pr i and R i represent respectively the knowledge set of the product, the process and the resources used. Therefore, a knowledge base that encompasses these knowledge fragments can be represented by the set KB = {K i , i € {1...n}}. This decomposition is inspired from models found in the literature mainly UEML [START_REF] Vernadat | UEML: towards a unified enterprise modelling language[END_REF] and FBS PPRE [START_REF] Labrousse | Proposition d'un modèle conceptuel unifié pour la gestion dynamique des connaissances d'entreprise[END_REF]. The integration of knowledge into the ubiquitous decision-making assistant system is done by formalizing expert knowledge and by accessing to the existing information systems (ERP, PLM, MES, etc.). Thus, the foundation of the multi-scale structure is to reduce the information overload by giving the beginner, intermediate and expert workers only the appropriate amount of knowledge on the suitable format.

Ubiquitous knowledge access

In fact, managing access to factory knowledge base depends not only on the expertise level but also on multiple factors such as the activity, the role, etc. These factors constitute the operational context and should be managed (captured, inferred, stored, etc.) separately from the knowledge base. The context-awareness is considered as a core feature of ubiquitous computing [START_REF] Dhuieb | Activity theory based context model: application for enterprise intelligent assistant systems[END_REF]. It relies on a context notion with the aim of increasing the ubiquitous system capabilities in order to adapt the service they provide to the situation of the user.

Other communities refer to the context as the working situation defined in [START_REF] Houssin | Information system based on a working situation model for a new design approach in concurrent engineering[END_REF] as "the existence of relations between users and machines, the two co-operating together to reach a performance in a given mission". Situation-awareness is defined as an intermediate state of the decision-making process. Endsley [1995] proposed a largely accepted structuring approach used by situation-aware systems. The situation according to her can be divided into three complementary levels. The first level is the perception of the current state of situation elements. The second level builds a comprehensive picture by interpreting the current situation according to situation elements being perceived at the first level. The third level deals with the projection of future actions of the elements in the environment.

Situation-awareness and more generally the situation can be studied from many points of view and within different levels:

 The perception level of the situation and how it is linked to the cognitive ability: According to [START_REF] Belkadi | Proposition of a situation model in view to improve collaborative design[END_REF], three representation levels of the situation might be distinguished: The Real situation includes all entities of the environment; The Observable situation is the sub-set of entities that can be considered by one actor from the real situation according to his perception capacities; The useful situation focus on the observed entities judged as pertinent by the actor in the realization of the task.

 The link between the situation and the decision-making process: The concept of situation plays an important role in the decision process and the deployment of a specific competency by an actor for the realization of his mission [START_REF] Bonjour | An internal modeling of competency, based on a systemic approach, with sociotechnical systems management in view[END_REF].

 The link between the situation and the collaborative work: A number of studies about situation awareness have explored how technology can be used to improve it in dynamic and knowledge-intensive environments [START_REF] Blandford | Situation awareness in emergency medical dispatch[END_REF] and to support collaborative work in globally distributed teams [START_REF] Jang | Virtual team awareness and groupware support: an evaluation of the TeamSCOPE system[END_REF].

Based on the above properties, a context model is proposed as part of the global knowledge model.Three complementary dimensions are distinguished in this model: organizational, operational and user-centric (Figure 3).

 Operational dimension is to determine, in execution time, in which processes the worker is involved. The process is broken down into a set of activities that can, in turn, be divided into a multiple number of tasks to be assigned to the right persons.

 Organizational dimension intended to determine to which department does the worker belong

and what is his/her exact role in this organization? Linking expertise domain to process helps identifying all types of knowledge required in a particular business process, activity or task.

 User-centric dimension is related to the user profile. It describes the user according to his/her competency, experience and expertise domain. Knowledge restitution is then organized according to his/her profile.

Taking into account these context dimensions, shows the proposed context model used to handle contextual information in the DFA framework.

High speed simulation with PGD method

In the era of digital manufacturing, simulation is a valuable IT instrument for supporting the continuously challenge of improving product quality and reducing the cost of non-quality. Offline and online simulations models have been used at different levels of the manufacturing system [START_REF] Mourtzis | The role of simulation in digital manufacturing: applications and outlook[END_REF]. The application of simulation in the decision-making process for manufacturing can be categorized into two main categories: long-term simulation is used in the design and configuration of the manufacturing system [START_REF] Truong | Simulation optimization in manufacturing analysis: simulation based optimization for supply chain configuration design[END_REF]]. Short-term simulation is used generally for production system control during the production [START_REF] Rao | On-line simulation for shop floor control in manufacturing execution system[END_REF].

The novelty of the proposal is to dedicate high speed simulation mainly for real time to analysis of operational operations at work station level. Indeed, this is not common for conventional decision support systems, where simulation is generally dedicated to the actors of the planning and operational management departments. To answer the real time constraints, PGD-based (Proper Generalized Decomposition) method [START_REF] Dumon | Proper general decomposition (PGD) for the resolution of Navier-Stokes equations[END_REF] is used as a background for high speed simulation to predict the mechanical transformation of the product structure during the manufacturing operations. By means, the worker at the shop floor level can anticipate his/her decision by testing several combinations of process machine parameters and observing the results on the product simulated model before acting in a real working environment.

The Proper Generalized Decomposition (PGD) is a recent methodology of simulation designed to meet both requirements [START_REF] Chinesta | PGD-based computational vademecum for efficient design, optimization and control[END_REF]. The main steps are:

 Identify the process variables that need to be controlled through simulation for one decision.

 Identify all possible combinations of process variables and related variation ranges of values.

 Establish a table of conversion that links the Process Variables and the Physical Variables, that is, those governing the physical behavior of the system.

 Compute a Computational Vademecum (CV) that encloses the physical behavior of the system for every scenario. This part constitutes the main scientific interest of PGD.

 Post-process the CV output data when it is of a physical nature (e.g. displacements, stresses) and probably of scarce interest for decision-maker who prefers practical indicators.

The CV encloses the behavior of the system for every combination of process (or physical)

variables. This causes a combinatorial explosion, where the number of possible scenarios grows exponentially with the number of variables. PGD addresses this kind of problems efficiently because it is based on tensor product representations, also known as separated representations, which can be understood as a compressed version of the data. The CV is therefore stored in such a compressed format. A file format called PXDMF (based on XDMF) has been developed to handle separated representations [START_REF] Bordeu | Abaques Numériques : Visualisation et Post-Traitement de Solutions à Variable Séparée[END_REF]. The PGD algorithm enables the computing of the CV directly into compressed formats by solving the physics partially described by differential equation.

ARTUR: Software architecture and graphical interfaces

Software architecture

As shown in Figure 4, the generic conceptual architecture of the DFA is composed of three main layers: Human-Computer Interaction (HCI) layer, the application layer and the data layer. The humancomputer interaction layer provides different modalities to visualize and exploit information and assistance provided by the DFA.

The data layer contains the knowledge base and the context base that stores all useful information about working situations that may occur in a production line. Some data are collected from other business information systems through specific Enterprise Service Bus (ESB). This technique guarantees better interoperability between the DFA and information systems by means of available service invocation in the ESB [START_REF] Schmidt | The enterprise service bus: making service-oriented architecture real[END_REF]. However, the implementation of such end-to-end features depends on how the existing components communicate with each other.

The application layer is the core elements of the DFA framework. It receives user requests from the HCI layer, extracts inputs from the data layer and realizes various reasoning and computations to provide a given decision. This layer contains five modules:  Context management module: deals with the acquisition, inferring and storing of contextual information, side by side with the adaptation engine. These operations allow the DFA to understand the current situation of the user through a matching with similar situations.

 Simulation management module: implements high-speed simulation techniques for the analysis of products' transformation behavior. It manages resulted simulation files that can be exploited through a particular reader deployed on the client side.

Man -Machine Interactions

Knowledge restitution is a critical issue for any decision support system and the profile of the user, his/her level of expertise and his/her working context should be considered to be sure that the delivered information is useful. A set of graphical user interfaces (GUI) and mobile applications have been developed as a communication layer of the DFA to support interactions with variety of actors depending on their experience levels. These interfaces are developed using HTML5 and JavaScript

Bootstrap and was adapted for both personal computer and mobile operation systems for further facilities of use in every working situation.

The main graphical user interface is composed of five main functionalities classified In five separate tabs respectively as shown in Figure 5. However, every user is supported by a set of functions according to his profile and his context of work. The related functionalities are displayed / hidden accordantly.

 Knowledge management section helps the expert to add information about new fabrication processes (i.e. manufacturing sequences, certificates, material, resources) and the link to some formal rules and procedures to be followed when realizing these processes.

 Simulation tab allows the administrator or authorized experts to add new simulation files and to connect the simulation parameters defined in the simulation model to the parameters metadata to be used by the operator in the mobile application.

 Technical documents section allows the administrator (or authorized experts) to update/modify technical documents (like notices, procedure, component data sheet, etc.) and linked these documents to the related products or manufacturing according to the knowledge model.

 Best practices section allows experts to capitalize their experience and their suggestion to perform the daily activities or to resolve some current problems. This kind of knowledge is informal and not imposed by the company like formal procedures. However, only experimented actors are authorized to populate this knowledge repository and this requires strong validation steps before making it available for all actors.

 User's profile administration is used by the administrator to define user profiles and the related data access strategies. Three levels are distinguished: novice, intermediate and expert. The blue interfaces are dedicated to the exploitation of stored knowledge and information.

When the operator connects to his interface he can get directly access to the recent tasks assigned to him with the reference of the related part. He is also informed by new procedures and standards in relation with the scope of his work. A set of key words is coupled with every procedure to help the operator rapid understanding of its content (Figure 6). At any moment, the operator can access to the details of the procedures and technical data through a simple query with the good key words. He/she can download the related technical documents, adapted to his /her competency level and profile (Figure 7).

Key function: high speed numerical simulation for real time assistance

One of the important applications of the DFA is to provide useful knowledge inferred from offline simulation models. This section describes how the PGD method is integrated in the DFAto perform high speed simulation as a key function of the DFA. An application scenario from an industrial use case is conducted to illustrate the efficiency of the proposed solution.

Integration of PGD-based simulation in the DFA

The simulation function aims to support contextual accessing to simulation numerical models for various workstations in the production line as shown in Figure 9. The simulation models are realized in offline and stored in a specific PXDMF file format to be exploited in real time through a PXDMF reader deployed on the client side. The process starts when the user sends a request to simulate the manufacturing process before acting with the real machine. The context management module begins with the process of contextual information acquisition. This process includes automatic context sensing from the ERP system and physical sensors in addition to other contextual information that can be filled in by the user (e.g.

working order, process parameters). The next step is to apply inferring rules to the information set in order to derive additional information to clarify the situation. This inferred information is then compared to other information already stored in the context database in order to extract the reference of the current situation of the user.

In case that there is no simulation model satisfying the worker's needs, an interactive process is started to support the creation of new simulation models tailored to the specific problem. As it is shown in Figure 11, the worker starts simulation by introducing the references of part and the manufacturing process (definitions are already available in the knowledge base). When starting the simulation module, the system will search for existing simulation models. If no adequate simulation model is found, the system notifies the problem to the experts who will define the new case and the related simulation models. After validation of this model, it will be proposed in the knowledge base.

Simulation data model

In coherence with the exploitation workflow proposed above, the model structuring the data manipulated by simulation function is illustrated in the UML class diagram of Figure 12. This model is implemented as part of the knowledge base dedicated to supports the simulation management module. The integration with the context meta-model is achieved through the class "Process". For each simulation file, a Meta-document is created to link the file with other meta-data in the knowledge base. In addition, the "Simulation details" class is linked to all used simulation Meta-docs to manage the whole list of simulation parameters and properties. Each process or part type is linked to a set of categories according to the desired simulation purposes. Part and process categories are defined by the process engineering expert following a set of potential properties (e.g. Medium length, high temperature, etc.). The simulation file is defined as a combination of one process category and a set of simulation parameters to be instantiated dynamically according to the real values of process parameters. These values are defined by the worker during his/her problem solving request.

The association class "Mapping" contains all mapping rules linking each process parameter and its related simulation parameter. Every parameter can has one or many instances according to the problem to solve. The values of the part parameters are stored in the simulation database manually by the worker or automatically from the parsing of the material certificate of the related part batch.

Application of the PGD-based simulation

Method configuration and implementation

The scope of the proposed solution is to analyze the mechanical transformations behavior of the product during the forming process. The physics involved in most of Material Forming Processes are classic and well understood but still difficult to simulate numerically.

To resolve such kind of problems with the PGD method, a Newtonian description of the mechanics of an elastic solid is considered. The equation governing the mechanical behavior can be written in terms of a partial differential equation that is not reproduced here for the sake of simplicity. Solving such a differential model implies solving the displacement field for which the internal forces (stresses) and external forces (loads, reactions on the supports) are in equilibrium. The displacement field, denoted by , depends on many Physical Variables, denoted by , that may represent boundary conditions, initial conditions, geometrical parameters, material parameters, among others. These Physical Variables are directly related to Process Variables through a conversion table. PGD computes the displacement field using the following format:

Where are functions depending on each variable separately and " " denotes the tensor product.

We refer to [START_REF] Chinesta | PGD-based computational vademecum for efficient design, optimization and control[END_REF] for a review on the PGD algorithm to construct this kind of separated representation. PGD has also been successfully applied for stochastic modeling and for solving multidimensional models. As part of the DFA, PGD simulation models are deployed on handheld devices through mobile interfaces (Figure 13) [START_REF] Aguado | A Simulation App based on reduced order modeling for manufacturing optimization of composite outlet guide vanes[END_REF].

Illustrative use case application

In order to validate the utility of the proposed framework, experimentation has been realized on one manufacturing process from aeronautic industry. This process, stretching frames of aircraft fuselage component, is delicate and requires high precision on its parameters. For instance, the position of the frame on the machine, the types and the positions of the grippers attaching the frame as well as the stretching power and direction applied by the hydraulic cylinder impact the final deformation of the frame. Also, the process is sensitive to the materialcharacteristics of the part.

Regarding this case study, the main difficulties concern the need of accounting for large displacements and extreme deformations, inelastic material behavior, material transformations (e.g. metallurgical phase changes) and thermomechanical interactions. Although classic methods in Computational Mechanics can perform these kinds of simulations, they may need several days to complete. Days might be shortened to hours by combining specific, optimized implementations, and by increasing the computational power.

Several simulations with various combinations of parameters are realized offline for few part references, including variations on the material characteristics. The results are stored as PXDMF files in the simulation database. When selecting the reference of the part and range of parameters to test, the suitable PXDMF file is extracted and sent to the reader deployed on the client machine (following the mobile interface shown in Figure 13). Once the PXDMF simulation file extracted, the user can change the values of the process parameters: the yield strength, the curvature, the stretching and auxiliary tools geometry. As shown in Figure 14, the user can see directly the impact of his/her manipulation on the form of the frame (i.e. deformation from the nominal mold).

Figure 14. Simulation results as delivered to the assistant user.

Conclusions and perspectives

This paper attempts to set a clear vision about the different components and features of a decision-making assistant system and mainly how it can provides context-aware support for workers at the workstation level. The proposed system highlights the uses of ubiquitous computing techniques and high speed simulation as key enablers to implement original smart applications for various working situations in the industry of the future.

The contribution of this paper is described in three phases; the idea phase clarified through a conceptual view of the assistant, the design phase presents the DFA architecture and the usage phase that outlines the maturation of a solution related to contextually accessing simulation models.

An application scenario was conducted on a real industrial case from aeronautic domain. The aim was to validate the principle of solution and evaluate the interest of such solution for industrial company. The solution is still at the prototype level because of all technical and security constraints linked to the implementation in a factory. Future work on interoperability and knowledge base population are under planning to fix these issues.

Indeed, interaction between the human being and the machines, (more generally the environment) is still underestimated by developers. Designing an assistant system that must interact with various users and support their daily works is a tough task and the problem of knowledge capitalization and acceptability should be studied further. Also, the use of this framework requires effort from experts to add the useful knowledge. This can increase user workload and require a new organization. The validation process is defined to accompany the deployment of such process. The main constraint encountered in the ubiquitous decision-making assistant system development resides in capturing and understanding the current situation of the user.

In the future, other application case studies have to be tested in order to build a sufficiently reliable proof of concept that can handle the scalability of the industrial environment. Actually, the simulation use case has been applied on aeronautical field. The extension to other industrial areas requests new simulation models with adequate parameters.

Other disciplines and research fields may take benefit from the work presented in this paper. For example, the ARTUR framework can be implied to build contextual recommending systems. Research works on context-awareness has made a good progress on other fields like medicine, transportation, tourism, etc. This work gives useful vision on how these advancements can be translated into the industrial field. This of course requests a huge effort that opens several interesting research perspectives and industrial applications.

Figure 1 .

 1 Figure 1. From distributed systems to ubiquitous systems:everyday life VS factory.

Figure 2 ,

 2 illustrates the relation between the portability of the DSS and the network type used in the implementation. As we can see, types of DSS have moved from individual DSS to a new category of DSS,based on the ubiquitous computing vision,in which context

Figure 2 .

 2 Figure 2. Evolution of DSS: an Illustration based on[START_REF] Kwon | UbiDSS: a proactive intelligent decision support system as an expert system deploying ubiquitous computing technologies[END_REF].

Figure 3 .

 3 Figure 3. Proposed context model.

Figure 4 .

 4 Figure 4. Software architecture supporting ARTUR

Figure 5 .

 5 Figure 5. Main GUI for knowledge management administration

Figure 6 .

 6 Figure 6. Listing of appropriate procedures and best practices

Figure 7 .

 7 Figure 7. Simple access to the procedure data and technical documents

Figure 8 .

 8 Figure 8. production monitoring interface

Figure 9 .

 9 Figure 9. Illustration of the contextual access to simulation use case.

Figure 10 .

 10 Figure 10. Proposed workflow for simulation data extraction (BPMN).

Figure 11 .

 11 Figure 11. Scenario of creation new simulation models (UML Activity Diagram).

Figure 12 .

 12 Figure 12. PGD-based simulation data model (UML Class Diagram).

Figure 13 .

 13 Figure 13. Exploring a PGD Computational Vademecum on a smartphone (left) and on a tablet (right).

  The UDKE (User, Device, Knowledge and Experience) is a conceptual model of the maintenance support tool that combines knowledge, user experience and Augmented Reality techniques. Even though the system relies on SOUPA ontology known by its ability to handle contextual information, nothing is mentioned in this work about handling different situations that a

The proposed framework is based on a shared ontology designed to model and support pervasive computing applications called SOUPA (Standard Ontology for Ubiquitous and Pervasive Applications).

  Comparison between the DFA system and other DSS.

	System / Framework	Description	Situation perception	Real time assistance	Collaboration facilities	MMI	Contextual access	Legacy tools connection	Application domain
	CARMMI [Espindola et al., 2013]	Intelligent system for breakdowns prediction and industrial machines monitoring.	Not supported Supported	Not supported	Mixed reality Desktop interface	Not supported	Supported	Industrial maintenance -Can be mapped to different domains
	UDKE [Toro et al. 2007]	Knowledge based system for industrial maintenance	Considered but not implemented	Not supported	Not supported	Mobile reality interface Augmented	Supported	Not supported	Industrial maintenance
									Product
	UbiDSS [Kwon et al., 2004]	Framework of ubiquitous decision support systems	Not supported Supported	Not supported	Mobile interface	Supported Supported	recommendation for customers -Can be mapped to different
									domains
	Simulation-based[Klein et al., 2008]	Decision support system for product flow control	Supported	Supported	Not supported Web interface	Not supported	Supported Product flow control
	[Kong et al., 2000]	Intelligent decision support system for metal forming industry	Supported	Supported	Not supported Not indicated	Not supported	Supported Metal forming process
	DFA	ubiquitous decision-making assistant system	Supported	Supported	Considered but not implemented	Virtual/Augmen ted reality Mobile/desktop interface	Supported Supported	Manufacturing operations -Can be mapped to different domains

Table1:

Acknowledgments


Dra Arq Estelle Thibault

dir. Drexler Arthur

Pfammater Ulrich

Harvey and Architectural Training in Europe

Was the beaux-arts culture international? To what extent was European academic training in architecture shaped by exchanges, hybridizations and circulations between various pedagogical models?

In the second half of the 19 th century, schools specialised in architectural training were a geographical network of internationally attractive institutions, polytechnic institutes and fine art schools. Their pedagogical models have often been opposed to one another as reflecting different conceptions of architecture. On the one hand, the more artistic model promoted by the architecture section of the École des Beaux-Arts in Paris foregrounded skills in composition above all else. 1 It relied on a tradition of ateliers and competitions that fostered emulation between students. On the other hand, polytechnic schools, which first appeared in Paris after the Revolution and were already well-established in Germany (Karlsruhe, Stuttgart, Berlin), offered to train students as engineer-architects with a solid scientific background and used a more traditional form of pedagogy with lectures and graded exercises. 2 These institutions were often in competition with one another, but that did not prevent interactions and mutual influences. Individual students or teachers moving from one school, one city, or even one language, to another, reinforced these relations.

Student mobility was variously motivated in a discipline where travel tours had always been an integral component of education. It was also the result of great spatial disparities in terms of available training programmes. In fact, Switzerland and Great-Britain were late in having

schools like those in France and Germany, which explains why young aspiring architects left their countries and attended different schools successively. 3 These students participated in building reputations and hierarchies between institutions, producing collective trajectories, which reflected means and career strategies. While fostering comparisons and competitions between schools, students who became architects and sometimes-even teachers were vectors of transfers and exchanges. They contributed to the importation of methods, the translation of concepts, and the hybridization of contents. Therefore, they made local differences more visible and at the same time participated in the homogenisation of European architectural culture.

To illustrate such phenomena, I will present the case of Lawrence Harvey (1845-1920), who typically embodies the movements and transfers of experience I have just mentioned. Born in Geneva as a British citizen, Harvey was the son of an English teacher and a Swiss portraitist.

He studied architecture at the Polytechnic institute in Zurich (from 1864 to 1867), then at the École des Beaux-Arts in Paris (from 1868 to 1872). He then settled in London in the hope of becoming an architect and teacher. Having failed in both careers, he came back to Switzerland in the early 1890s and taught for a while at the École des métiers in Geneva.

Harvey mostly distinguished himself as a journalist for the French and British architectural press, an activity he started at an early age, as early as 1868, while still a student. He is mostly known for having contributed to disseminate the ideas of his former architecture teacher in Zurich, Gottfried Semper, in London and Paris in the 1880s. 4 He has also been identified as one of the promoters of the model of the Paris École des beaux-arts in Great Britain. 5 What I'd like to underline is his role as a critical observer of the various training systems in architecture, and how he was able to foster exchanges on content and pedagogical methods between the continent and England. To do so, I rely on two types of sources, which in fact participate in disseminating ideas. First, there is Harvey's private correspondence held at the Geneva Library. 6 These letters provide an overview of Harvey's mindset and shed light on the academic and professional strategies informing his public interventions. Secondly, I examine the vast number of articles he published in various architecture periodicals published in Europe as well as in Chicago, thus exporting his ideas to North America. These texts show how keenly his studies. Also, the emphasis on scientific classes had not enabled him to improve. Due to the lack of such skills, he failed his certificate and discussed his situation with Gottfried Semper, his teacher. 8 Semper himself had travelled across Europe as a student and teacher and therefore knew well the various types of pedagogies of the mid-19 th century. His exile had forced him to accept the position of director of the architecture school at the Zurich Polytechnicum in 1855; however, he had always regretted not having freedom to design the curriculum according to his own views. 9 He too thought that studies should last longer and that students should be encouraged to carry out actual architectural projects; instead, the programme comprised a multiplicity of courses and exercises. To Harvey and many other students, Semper had therefore suggested they should complement their training at the École des Beaux-Arts in Paris, where they would also enjoy numerous architectural models in the monuments of the capital.

Retrospectively, the solid technical and scientific training of the Zurich polytechnic institute proved helpful for these students to master the Parisian curriculum. [START_REF]The Zurich school, which can only be looked at as a preparatory school for the École des Beaux-Arts[END_REF] In his 1870 "Continental schools of architecture", Harvey compared the length of studies-3 years in Zurich versus an à la carte curriculum in Paris, the average amount of time to become certified being 7 years-, the place of architectural composition itself in the curriculum, as well as the artistic autonomy given to students. He soon concluded that the École des Beaux-Arts was far superior: "in the opinion of many competent judges, the mental discipline of the Polytechnicum is too rigid and tend to cramp the originality of pupils". [START_REF] Harvey Lawrence | Continental Schools of Architecture[END_REF] Having defended the Parisian system of ateliers and concours [START_REF] Harvey Lawrence | Paris Studios and the Grand Prix de Rome[END_REF] [START_REF] Harvey Lawrence | The French Diplôme d'Architecte and the German System of Education[END_REF] . Mutual teaching and learning, emulation, the freedom left to students in building their own curriculum were opposed to the "schoolboy principle" 14 of the "German education system". Such pedagogy could be efficient, but it was inadequate to develop true artistic personalities.

In a series of humorous "English letters" published in the French weekly La semaine des constructeurs in 1878, Harvey made similar comments on the British situation. [START_REF] Harvey Lawrence | Lettres anglaises[END_REF] He criticised the lack of any real architectural training programmes devised at the State level and pointed at the many excesses resulting from a training at the sole hands of professionals, which mainly relied on pupillage. While some architects made sure they were truly providing their pupils with practical, artistic, and intellectual knowledge, others simply exploited them. Charles Dickens had already exposed the system's abuses in his 1844 novel Martin Chuzzlewit, and architecture periodicals such as The Builder promoted more virtuous practices. [START_REF] Mark | Architecture. Art or Profession ? Three Hundred Years of Architectural Education in Britain[END_REF] Lawrence Harvey offered his French counterparts a Dickens-like picture of the English training system rather than a systematic report on its pros and cons. Indeed, his contribution was a deliberately ironic parody of a work contract between an architect and his apprentice: the document drafted by notaries Dodson and Fogg put young Wastepaper under the authority of architect Greatcanon in exchange for a huge sum of money, without any obligation for the latter to train his apprentice in return. 17 In contrast, Harvey insisted on the warm welcome that Parisian "patrons" would grant their young students at the École des Beaux-Arts, thinking probably of his own master, Léon Ginain. But he might also have had in mind the interesting year he spent working at the office of the Geneva-based architect Jacques Louis Brocher before enrolling at the École des Beaux-Arts. In fact, his fierce attack on apprenticeship hid a more balanced appreciation of a system that he could see evolving in a more promising direction. A decade later, he thus claimed that pupillage could easily be turned into something close to the Parisian system of ateliers. All that was needed was to allow young students to access complementary training and to make sure employers benefitted from their pupils' success by being mentioned when they would win competitions. 18 Also, Harvey had well identified the advantages of the British architectural environment, which compensated the lack of virtually any public training system. To his French readership, he extolled the many resources available to a young Englishman willing to learn the craft by himself; among these, architecture journals were particularly important as they took their educative role very seriously. The Builder, a weekly created in 1843, thus provided a template for later French periodicals such as the Semaine des constructeurs (founded by César Daly in 1876) and its competitor, La Construction moderne (founded by Paul Planat in 1885). Harvey also stressed the importance of the debates triggered by public competitions, which the press magnified: "Students can therefore see the best projects that were submitted and learn about the discussions around them. It is as if the competition's exhibition were taking place all over England at the same time; in short, it is the École des Beaux-Arts de Paris, but on a much larger scale." 19 Finally, Harvey also applauded professional institutions taking action to set up a more formalised training system. 20 At the Royal Institute of British Architects for instance, where he was admitted in 1882, the issue was becoming more and more prevalent. In fact, Harvey taught some classes offered by the Architectural Association, founded in 1847 by young voluntary architects who decided to take charge of their own training, and whose pedagogical missions 17 had greatly developed. Having himself been a member of a student association in Zurich, Harvey knew how profitable such activities could be.

Harvey was in such a position that he would encourage his contemporaries to make the most of the three systems: the pedagogy of polytechnic schools, the mutual teaching prevailing in the ateliers, and the English self-learning method.

Disseminating composition principles: French unity versus English individuality

Harvey also developed an expertise on the main characteristics of French and English architecture. In his correspondence with his brother Robert, he discussed the articles he wrote for the British press in the early 1870s while living in Paris. Robert, who was then a student of English literature in London, served as intermediary with the journals and finalised his brother's texts. 21 Together, they identified a marked contrast in the artistic production of the two countries, in literature and in architecture, as the result of deep political, moral, and cultural differences. They thus opposed the French Mind that was dominated by a centralizing spirit, to English individualism and its fondness for independence. 22 In the wake of an article precisely entitled "The French Mind," and with the help of his brother, Lawrence Harvey published two texts on Charles Garnier's Opera in Paris [fig. 1], in which he tried to demonstrate "how the plans of French buildings are the organic outgrowth of that centralizing spirit": "the puzzle, then, for the architect of a playhouse is to find a simple system of lines which will both satisfy the demands of the five main divisions of the house and the spectator's instinct of organic unity." 23 The modes of composition taught at the École des beaux-arts were made explicit in these texts, while being implemented by the young architect in his own school projects. The description of Garnier's Opera thus turned into a lecture on the principles that were transmitted orally in the studio. Harvey highlighted the fact that the plan fit in regular geometrical figures and that the different parts were subordinated to the overall composition; the various elements of the programme were distributed hierarchically according to their relative importance, from the 21 BGE, ms. 5325, Harvey Papers, correspondence 1870-1884. 22 stage and the main staircase to the ancillary spaces. There is a much more extensive version of this rather short article in the brothers' correspondence, revealing a deep theoretical background. Harvey was enthusiastic about this text and felt he could continue with "a series of comparative articles on the Paris monuments by the modern school": "I will relate them to my previous articles like an exhibition where the reasoned study of architecture takes you, I will try to make the English understand the architectural thinking of the French, their plans drawn from a general conception of the totality, the study of proportions in either plans or elevations, and finally the influence of the French spirit on the dispositions and character of their buildings. I will start with the main public monuments, the Opera, the new court of cassation, the École des Beaux-Arts, Les Halles, churches, and end with private mansions and rented houses." [START_REF] Harvey | [END_REF] The project did not come through in the 1870s but-I'll come back to this later-it eventually developed into a series of lectures that Harvey gave in London in July 1887. 25 After having explained the French Mind to British architects, Lawrence Harvey, once settled in London, set out to make the French understand the irregular dispositions that were valued across the Channel. In La semaine des constructeurs, he presented the Scottish architect Richard Norman Shaw and stated he was as important as "Duc and Duban in France," [START_REF] Harvey Lawrence | Le style Queen Anne ou des romanciers architectes[END_REF] "an innovator and a real master," even though his way of organising plans was the complete opposite of French unity: "Ideas of growth and development, [this] is what the British architect holds dearest." [fig. 2] He continued his demonstration in a series of articles published in La construction moderne in 1885. He described the main characteristics of domestic architecture, in utter contrast with the symmetrical and hierarchical modes of composition being taught at the École des beaux-arts. The Frenchman, whose ideal was public monuments, wanted to apply their regular order to private buildings: "The Englishman is not as embarrassed, since his ideal is private life, whose essential trait is freedom […] the absence of any system […] He thus puts what you, French architects, would call the disconnected [décousu], at the core of his architecture […] the décousu is taught to the young English architect as the monumental, the systematic is to the young Frenchman." [START_REF] Harvey Lawrence | La construction moderne en Angleterre (4)[END_REF] These views were published in a series of publications which participated in disseminating the aesthetic of English cottages in France, in the wake of Viollet-le-Duc's Habitations modernes (1874). [START_REF] Jacques | Composition, non composition. Architecture et théories, XIXe-XXe siècles[END_REF] Harvey's texts could be reactions to those of Émile Rivoalen, 29 who had commented on various features of English cottages. These texts also coincided with Harvey's adoption of a hybrid neo-Renaissance style in which rooms achieve their individuality by displacements and façade extensions, as illustrated by the villa project he published in The Architect in 1885. [START_REF]Design of Villa Campden Hill[END_REF] [fig. 3] Thus the young professional opportunistically played on both his architectural cultures and at the same time promoted the composition methods he had learnt in Paris and then in London in practice and in periodicals.

Knowledge sharing: perspective drawings and descriptive geometry

Transfers of methods and ideas between England and the continent also involved the modes of representation that were privileged for the various conceptions of the architectural project: perspective, which was associated to picturesque compositions, and geometry, the instrument of hierarchical regularity. Harvey introduced his French counterparts to the drawing methods that were currently used in English offices, including the "Centrilinead," a device that simplified the drawing of perspective views. [START_REF] Harvey Lawrence | Lettres anglaises[END_REF] [fig. 4] Harvey favoured this intuitive and practical approach, in contrast with the excessively theoretical and complex teaching of perspective at the École des beaux-arts, as a consequence of which French architects turned away from it. [START_REF] Harvey Lawrence | L'enseignement de la perspective[END_REF] He also drew conclusions on the impact of these drawing methods on the illustrations of journals on both sides of the Channel. Harvey had been disappointed by the engraving of the plan illustrating his text on the Opera. It showed "little architectural feeling, it [failed] to distinguish between the largest and smallest columns, without any light grey tint for the residual spaces." 33 In comparison, English periodicals were illustrated with numerous perspective views. As early as 1879 in La Semaine des constructeurs, Harvey had underlined the advantages of photogravures in English journals such as the Building News, which published facsimile reproductions of some architects' original drawings, among which perspectives, most often in pen and ink. 34 The dissemination of perspective in French periodicals happened later than in England; most importantly, it was motivated not by a concern to reproduce the architects' sketches directly, but rather by the fact that engravings were made from photographs. 35 Daly, who was extremely mindful of printing techniques, personally wrote to Harvey that his article had taken him "to deep philosophical thoughts" 36 on the variations of taste on both sides of the Channel. Although he was convinced of the value of publishing drawings that were as close to the originals as possible, Daly regretted he could not do so because, first, French architects did not make any pen-and-ink sketches that could be easily printed, and secondly, because readers did not appreciate this kind of illustrations. Daly told Harvey about the negative reactions that followed the reproduction in 1877 of the sketch of Alfred Waterhouse's Manchester city hall from the English journal The Architect. 37 He never wanted to repeat the experience. However, in 1882, Harvey managed to have some photogravures of his drawings published in the Semaine des constructeurs as illustrations of a description of two of his warehouse projects in London. 38 Harvey had made the drawings himself and was thus able to insert some witty references to his Genevan origins, in particular a poster for an exhibit of Swiss art that he organised in London. 39 [fig. 5] Such images were so rare in the Semaine des constructeurs that the editor felt it deserved a pedagogical note: "This drawing is a photoengraved reproduction of a pen-and-ink drawing by Mr Harvey himself; it retains the author's desired effect and is an exact rendition of his thinking. How much we wish that French and foreign architects would take the trouble to draw themselves their works, large or small, if only by making simple pen sketches that the photogravure could follow line by line, 34 HARVEY Lawrence, "Lettres anglaises", La Semaine des constructeurs, vol. 3, n o 28, 11 janvier 1879, p. 325-326. 35 See BRESSANI Martin et SEALY Peter, "L'architecture recadrée : la photographie et le nouveau régime visuel dans la presse architecturale après 1870", in Hélène Bocard and Jean-Philippe Garric (dir.), Architectes et photographes au XIX e siècle, [Online], Online since 18 July 2016, connection on 11 February 2019. URL : http://journals.openedition.org/inha/7092 36 Daly to Harvey, 1 July 1879, BGE, ms 5325 f°72r. 37 "Nouvel hôtel de ville de Manchester", La Semaine des constructeurs, vol. 1, n° 23, 8 December 1877, p. 271. About this in-text image, Daly mentions a "photographic reproduction". We have not been able to determine whether it was an engraving from a photograph of the original sketch or one of the first photogravures that made it possible for illustrated periodicals of the 1870s to reproduce in-text black-and white line drawings with no grey shades. On the matter see GERVAIS Thierry, L'Illustration photographique. Naissance du spectacle de l'information, 1843-1914, PhD, Paris, EHESS, 2007, p. 141-142. It is striking that while Harvey was trying to import English drawing techniques in France, he was also promoting descriptive geometry back in London. In the 1880s, as he was building a career as a teacher, he mentioned the specific skills he had acquired in Zurich and later in Paris.

Thanks to his correspondence, we can identify him as the anonymous writer of "The Student Column" which offered weekly lessons in "descriptive geometry" from February 1885 onwards. 41 But his hopes to publish the series as a geometry treatise bearing his name were dashed. However, he used this experience to teach a stereotomy class to masonry students at the City and Guilds of London Institute in late 1886. This establishment had been founded in 1878 to develop a national system of technical education. In order to attract young architects to his class, he advertised in the press this largely unknown field of studies in England, "though it forms an integral part of the curriculum of most Continental schools". 42 With the support of the Architectural Association, his practical class of masonry became quite successful and was even for a while considered as the core part of a potential "English polytechnic institute" providing solid technical and scientific knowledge to future architects. 43 His teaching experience at the City and Guilds Institute also reveals Harvey's capacity for adaptation, if not opportunism.

Even though he was personally convinced of the pedagogical superiority of the École des beaux-arts in training architects, he did not hesitate, when the time came, to promote the foundation of a polytechnic institute in which he could invest his scientific skills.

German history and aesthetic lessons

Among the various pedagogical methods that Harvey promoted, one must also mention the importance he gave to history and aesthetic courses, in accordance with what he had learnt during his first years studying in Zurich. Even though he complained about the predominance of scientific courses, he developed a passion for the art history courses delivered by Wilhelm 40 La Semaine des constructeurs, vol. 7, n o 10, 2 September 1882, p. 116. On both these illustrations is written "Fernique Ph. Sc", which indicates that it is the work of photoengraver Albert Fernique. 41 With this series of lectures, Harvey wanted to produce an eclectic synthesis of architectural knowledge from the main intellectual centres he had visited. His concern to report on the latest developments in architecture and compare them was shared by the architecture press of the time, in which references were international. This was particularly the case of American journals such as the Building Budget, which promoted European culture by translating into English excerpts from Viollet-le-Duc and of German authors, for instance August Thiersch.

But French journals such as La Construction moderne and L'Encyclopédie d'architecture also were anxious to report on the art of building in other countries.

Conclusion

With his singular trajectory, the variety of his written production, and his own teaching experiences, Lawrence Harvey stands as a significant figure in the architectural dialogues that took place in late 19th-century Europe. Admittedly, he did not build much, did not publish any books, and taught only a little; also, his articles were published anonymously or under pseudonyms. But it is precisely the difficulties he encountered as an aspiring professional architect and teacher that incited him to make the most of his multifaceted training and detailed knowledge of the various education systems, at a time when English institutions were looking for models to develop their own architectural training curriculum. Although he was personally convinced that the Parisian system of ateliers was the most efficient, he was able to broaden the focus by identifying the potential of other systems without neglecting the importance of professional apprenticeship nor the role played by a larger cultural environment, including periodicals. Similarly, his taste for the regular and hierarchical compositions promoted by the École des Beaux-Arts shifted in contact with other models as well as with the clients' own taste, urban regulations and the profession's practices. Harvey was an observer of cultural differences but also a mediator who, like many other press correspondents, worked to mutual understanding and to the dissemination and hybridization of architectural ideas and their visual representations. Examining these mixing processes through their actors helps us understand how internationalisation made the beaux-arts culture open to a diversity of other practices.

Translated by Camille Joseph

3

  CRINSON Mark et LUBBOCK Jules, Architecture -Art or Profession? Three Hundred Years of Architectural Education in Britain, Manchester/New York, Manchester University Press, 1994 ; LÜTHI Dave, La construction de l'architecte : histoire d'une profession en Suisse romande 1800-1940, Neuchatel, Alphil, 2010. 4 THIBAULT Estelle, "Semper en version française : traductions et interprétations dans la seconde moitié du XIX e siècle", Revue germanique internationale, 2017, n o 26, p. 191-210. 5 BRUCCULERI Antonio, "Transfert du modèle Beaux-Arts dans le milieu londonien : autour de l'Architectural Association School dans les premières décennies du XX e siècle", Cahiers HEnsA20, 2018, p. 33-39. 6 Bibliothèque de Genève (BGE), Harvey Papers, Correspondence, ms 5324 à 5327. 3 | 17 aware of national discrepancies he was and how, because of his multicultural background, he could present himself as both an expert and a key player in the transfer of pedagogical models. By foregrounding the combined advantages of the Swiss, French, and British systems, Harvey developed an eclectic synthesis and outlined an ideal architectural education at the end of the 19 th century. Training methods in architecture: emulation, schoolboy system, pupillage and self-learning Lawrence Harvey first tackled differences in training methods in an article entitled "Continental schools of Architecture" 7 , published in The Builder in 1870. In this text, he compared the German and French systems on the ground of his own experience as a student at the Zurich Polytechnicum and at the École des Beaux-Arts in Paris. Unsurprisingly, the comparison resulted in favour of Paris where Harvey had studied in the atelier of Léon Ginain. In Zurich, Harvey had not been entirely satisfied with the training he had received, except the history classes he had enjoyed a lot. Contrary to fellow students who had taken preparatory classes or acquired more practical office training, Harvey had quite poor drawing skills when he began

  without altering anything."40 As a matter of fact, this genre of illustrations became more and more popular in French journals in the following years. The perspective views sent by Harvey participated in the process of the homogenisation of images, of their content and means of reproduction, in the European architecture press.

  In addition, Harvey recycled his previous contributions: his lectures on Semper, which he extended by reflections on the latter's architectural work, and his notes on Garnier's Opéra. In keeping with the project he conceived when analysing the building in 1870, he complemented his study by further examining the French compositions and by choosing illustrations from the most famous examples of his time. The Parisian works of Félix Duban, Henri Labrouste and Louis Duc were thus documented by plates from the Revue générale de l'architecture that were provided by Daly. Harvey also gave an overview of German architecture from Karl Friedrich Schinkel to Gottfried Semper and reused what he had previously published in French journals on the recent developments of British architecture. The end result was a picture of the various renaissance styles in the three countries, from general tendencies to local peculiarities.

Fig. 1 :

 1 Fig. 1 : "Plan of the new Opera-House, Paris" (Charles Garnier), The Builder, 1870, p. 466.

Fig. 2 :

 2 Fig. 2 : "English Country Houses" (Richard Norman Shaw), La Semaine des constructeurs, 1883, p. 583.

Fig. 3 :

 3 Fig. 3 : "Design of Villa Campden-Hill, Kensington" (Lawrence Harvey), The Architect, 1885.

Fig. 6 :

 6 Fig. 6 : "Semper's Theory of Evolution in Architectural Ornament", Transactions of the RIBA, 1884-1885, pl. XVI.

  as more adequate in 1870, he promoted it again in 1884 during a discussion at the Royal Institute of British Architects on architectural training.

	Lawrence Harvey's interventions matched those of another former École des Beaux-Arts
	student, Richard Phené Spiers

  HARVEY Lawrence, "Lettres anglaises", La Semaine des constructeurs, vol. 3, n° 16, 19 October 1878, p. 182. 18 "Architectural Association", The Builder, LI, n°2284, 13 November 1886, p. 715 ; HARVEY Lawrence, "Le meilleur système d'éducation pour les architectes", La Construction moderne, n o 21, 21 May 1887, p. 373-374. 19 HARVEY Lawrence, "Lettres anglaises", La Semaine des constructeurs, vol. 3, n o 22, 30 November 1878, p. 253-254. 20 HARVEY Lawrence, "Chronique. Le diplôme professionnel", La Semaine des constructeurs, vol. 6, n o 45, 6 May 1882, p. 530-531.

  HARVEY Robert, The French Mind, or, A Psychological Outline of the French Intellect and Character for the Use of Students of French Literature, London, Trübner and Co, 1870 ; HARVEY Lawrence, "The French Mind", The Builder, XXVIII, n o 1418, 9 April 1870, p. 280. 23 HARVEY Lawrence, "The new Opera House, Paris", The Builder, XXVIII, n o 1418, 11 june 1870, p. 465-466 and XXIX, n o 1499, 28 October 1871, p. 846-847.

  46 lessons were published in volumes 48 (1st semester 1885) and 49 (2nd semester 1885) and continued the following year. 42 "Practical Class of Masonry", The Builder, LI, n° 2282, 30 oct 1886, p. 625. The lessons were given from October 1886. 43 Lawrence Harvey to his brother Robert, 26 March 1887, BGE ms 5327, f°26r.

HARVEY Lawrence, "Continental Schools of Architecture", The Builder, XXVIII, n o 1407, 22 janvier 1870, p. 61.

Lawrence Harvey to his father,

August 1867, BGE, ms 5324, f°61r. 9 FRÖHLICH Martin, Gottfried Semper als Entwerfer und Entwurfslehrer, ETH Zurich, 1974 ; TSCHANZ Martin, Die Bauschule am Eigenössischen Polytechnikum in Zürich : Architekturlehre zur Zeit von Gottfried Semper (1855-1871), Zurich, gta, 2015.

HARVEY Lawrence, "La cité de Londres. L'architecture style Chicaneau", La Semaine des constructeurs, vol. 7, n o 9-10, 26 August and 2 September 1882, p. 102-103; p. 114-116.

This exhibition of Swiss art, organised by Lawrence and Robert Harvey, was held at 168, New Bond Street in London, from the 14th of March to the 25th of July 1881.

Lübke and Gottfried Semper. 44 In Paris he regretted that there were no equivalent courses and asked the director of the École des Beaux-Arts, Eugène Guillaume, that the library be open at night on the grounds that "art studies with no historical or aesthetic research to complement them" would be inchoate. 45 At the end of the year 1884, he participated in reviving interest in Semper's theories by giving a remarked lecture at the RIBA, 46 followed by another at the AA 47 the next year. [fig. 6] When his practical class of masonry was successful enough to make him hope he could play a major role in founding an architectural school based on the polytechnic model, Harvey also developed an ambitious series of four lectures entitled "Style and Styles in Building", which he delivered at the City and Guilds of London Institute in July 1887. Between October 1887 and September 1889, all these lectures were published in Chicago by the Building Budget 48 , a periodical dedicated to disseminate the latest news in European architecture in North America and for which Harvey also wrote "London Letters" under a pseudonym, Britannicus.

The four lectures, to which Harvey's brother contributed on both content and form, began with reflections on style, thus popularising Semper's complex ideas in highly accessible English.

They then spanned the entire history of architecture, from antiquity to contemporaneous constructions in France, Germany, and England, before ending with some personal remarks on his own work as representative of the three cultures. The published versions made abundant use of images. Harvey's private correspondence confirms that he used his own notebooks from Zurich to write the historical parts; as for the iconography, it came from Lübke's and Semper's books. Since he was concerned to present himself as heir to a broad German, French, and British culture, Harvey used some figures from L'Art de bâtir chez les Romains by Auguste Choisy and from Eugène Viollet-le-Duc's Dictionnaire raisonné, as well as references to works by George Gilbert Scott. 44 Letters from Lawrence Harvey to his father, September 1864-August 1867, BGE, ms 5324. 45 Lawrence Harvey to Eugène Guillaume (director of the École des beaux-arts), June 1870, BGE, ms 5325 ; Lawrence Harvey, "Continental Schools of Architecture", op. cit., 1870 : "one thing, however is wanting in Paris, a searching course of lectures on the history of art, accompanied by competitive examinations in that subject". 46