Gilles Galichet
email: ggalichet@gillesgalichet-consulting.com

Roberta Costa Affonso
email: roberta.costa@supmeca.fr

Vincent Cheutet
email: vincent.cheutet@insa-lyon.fr

Processes-oriented maturity framework for Lean Manufacturing with health-at-work and performance management objectives

Keywords: Health at work, industrial performance, maturity, organisational transformation, capability, Lean Manufacturing

Lean Manufacturing is recognised as an approach that improves companies' performance through the elimination of non-value-added activities. However, not all companies implement this approach since there is no standard method for doing so, and some authors have even identified it as a source of stress or occupational illnesses. In light of this, how can an action plan, for its implementation, be defined while guaranteeing the synergy between industrial performance and health at work? Maturity frameworks are tools that identify a company's level of capability regarding the studied parameters, and so can serve as a guide in their organisational transformation. In this article we propose a process-oriented maturity framework for Lean Manufacturing transformation that considers health at work and the company's managerial and operational performance. The framework is illustrated through a company's evolution over the course of a 5-year project, and is then discussed.

Introduction

Since its appearance at Toyota (TPS -Toyota Production System) and its popularisation in [START_REF] Womack | The Machine that changed the world[END_REF], Lean Manufacturing (LM) has been regarded as an approach that improves the performance of a company's production system. It can be applied to companies of different sizes and sectors [De Oliveira et al., 2019], allowing them to adapt to the constant changes in the market and to requirements in terms of quality, flexibility and responsiveness [START_REF] Bhamu | Lean manufacturing: literature review and research issues[END_REF].

LM supports continuous improvement of the system by focusing on increasing added value and eliminating wastes [Ohno, 1988]. However, many studies point out that the implementation of the Lean approach through these practices and tools attains varying levels of success [START_REF] Almomani | A proposed integrated model of lean assessment and analytical hierarchy process for a dynamic road map of lean implementation[END_REF], [START_REF] Hallam | Company self-assessment of lean enterprise maturity in the aerospace industry[END_REF], [Bhasin, 2011] and not necessarily sustainable over time. The gap in success or even failure of LM implementation is often attributed to the lack of standard LM implementation processes or framework [START_REF] Bhamu | Lean manufacturing: literature review and research issues[END_REF],

human factors [START_REF] Barouch | Learning from criticisms of quality management[END_REF]] (e.g. due to a poor understanding of the approach or to the resistance to change) and the lack of a Lean corporate culture [START_REF] Hallam | Company self-assessment of lean enterprise maturity in the aerospace industry[END_REF], [START_REF] Nightingale | Beyond the lean revolution: achieving successful and sustainable enterprise transformation[END_REF]. In this study we are mainly interested in the first two factors.

Concerning a standard LM implementation process, one of the difficulties in defining it is the fact that companies do not have the same levels of functional organisation, formalisation of procedures, work organisation, etc. It is therefore difficult to define an implementation process that will be taken up most companies. [START_REF] Moeuf | Strengths and weaknesses of small and medium sized enterprises regarding the implementation of lean manufacturing[END_REF] highlight these obstacles to LM implementation in the case of SMEs. As a result, many companies start Lean implementation by applying Lean practices (or 'quick win' tools) throughout the company, only to realise later that the results are not sustainable [START_REF] Bhasin | Lean viewed as a philosophy[END_REF].

To better take into account the organisational and managerial differences between companies, another way of understanding LM implementation is by using a maturity model or framework.

Maturity models are used to assess a company's level in relation to the associated parameters and to guide it in defining its evolution with a view to developing sustainable capabilities over time.

The maturity model was defined in [START_REF] Becker | Developing maturity models for IT management[END_REF] as a conceptual model that consists of a sequence of discrete maturity levels for a class of processes in one or more business domains, and represents an anticipated, desired, or typical evolutionary path for these processes. The Lean Maturity model or framework has been the subject of several recent studies [START_REF] Jørgensen | Lean maturity, lean sustainability[END_REF], [START_REF] Tortorella | Lean manufacturing implementation: an assessment method with regards to socio-technical and ergonomics practices adoption[END_REF], [START_REF] Zanon | Performance measurement and lean maturity: congruence for improvement[END_REF]. However the parameters of the models are often Lean practices and tools, which are difficult to use as a guide for the implementation of a Lean transformation process. For this reason, we argue that the maturity framework should be process-oriented, with the aim of integrating the parameters of the framework into one of the company's processes so that they can be managed and followed up. Thus, the company's processes will be modified (or new ones will be implemented) in accordance with the LM approach and in a sustainable way.. [START_REF] Koch | 10 commandments for the boss of a company implementing lean philosophy[END_REF] highlight the fact that when the Lean approach is introduced into a company, managers must be aware that results are the consequence of processes.

Furthermore, and to return to the second factor of interest to us, it is necessary for human aspects to be considered in the parameters of the framework. Since the 2000s, some authors have identified the implementation of the LM as a generator of stress [START_REF] Jackson | Lean production teams and health in garment manufacture[END_REF], [START_REF] Conti | The effects of Lean production on worker job stress[END_REF], or even occupational diseases [START_REF] Fairris | Workplace transformation and the rise in cumulative trauma disorders: is there a connection[END_REF], [START_REF] Valeyre | European foundation for the Improvement of living and working conditions[END_REF].

Others have found that, on the contrary, the Lean approach takes health at work into account [Joseph, 2003], [START_REF] Vinodh | Tools and techniques for enabling sustainability through Lean initiatives[END_REF]. A systematic correlation between the two factors has not been demonstrated, but it is possible that an inappropriate implementation of LM may lead to poorer working conditions and thus a negative impact on employees' health [Hasle, 2014], [START_REF] Hamja | The effect of Lean on occupational health and safety and productivity in the garment industry-a literature review[END_REF].

The literature review performed in [START_REF] Arezes | Workplace ergonomics in Lean production environments: A literature review[END_REF] concludes that "there is no consensus on how Lean principles affect the workplace ergonomics since most authors found positive (advantages) and negative (disadvantages) impacts". It is therefore important to ensure that the Lean transformation of the company ensures health, safety and good working conditions for employees and the maintenance, and improvement of human capital [START_REF] Machado | Framing maturity based on sustainable operations management principles[END_REF]. Accordingly, a holistic view of the LM implementation process is necessary not only to improve machinery and equipment, but also to involve human resources [START_REF] Tortorella | Lean manufacturing implementation: an assessment method with regards to socio-technical and ergonomics practices adoption[END_REF], [START_REF] Bocquet | Lean manufacturing, human resource management and worker health: Are there smart bundles of practices along the adoption process[END_REF]. We therefore posit that work organisation and sharing / collaborative processes have an influence on health at work and on the sustainability of results.

To tackle these issues, this paper proposes a process-oriented framework to assess the process maturity from the Lean Manufacturing implementation perspective and integrating human health factors. The framework 1 identifies the relevant parameters related to the implementation of LM approach including health at work. The contributions are twofold:

• We provide a framework which allows companies to evaluate their initial situation to implement a LM approach. This framework then becomes a guide for them to define the priorities of process transformation and so its Lean implementation path.

• This framework ensures respect for good working conditions in the Lean transformation process, integrating parameters for the development of human capital, and taking into account practices such as ergonomics and ergomotivity to guarantee health at work. The proposed framework is the result of a combination of bibliographical research and one of the author's involvement in several continuous improvement projects as a consultant in various industrial companies since 2008. These projects lasted between three and five years each, with companies of different sizes, different initial situations (in terms of economic context or internal occupational health), in different industries and so on. This method enabled us first to formalise a framework then to apply it. In this article we present a case study of the application of the maturity framework.

The paper is structured as follows. Section 2 briefly presents a review of the maturity models and frameworks from a LM perspective. In Section 3 the work methodology/research design is introduced. The proposed process-oriented maturity framework is then explained in Section 4. An example of the application of the proposed framework and its results in an industrial company is set out in Section 5, with a discussion on the applicability in other industrial companies. Finally, conclusions and research perspectives are discussed in Section 6.

Maturity model background

Generalities

The first maturity model, the Capability Maturity Model (CMM), was proposed by Watts Humphrey in the late 1980s to assess companies' capability in software engineering [START_REF] Yi | Comprehensive evaluation on the "maturity" of china's carbon markets[END_REF]. It was outcomes. The frameworks should help the analyst to better think through the problem by understanding the firm and its environment.

gradually extended to the Capability Maturity Model Integration (CMMI) version, which has been applied to several domains [START_REF] Ngai | Energy and utility management maturity model for sustainable manufacturing process[END_REF].

Since then, numerous maturity models have been proposed in various domains, such as risk management in complex projects [START_REF] Yeo | Risk management capability maturity model for complex product systems (CoPS) projects[END_REF], supply chain activities [START_REF] Reyes | Using experts to develop a supply chain maturity model in Mexico[END_REF], and product life cycle management [START_REF] Vezzetti | A benchmarking framework for product lifecycle management (PLM) maturity models[END_REF]. These models are seen as means of improving companies' skills in a specific area, as the sequence of levels and the requirements for moving from one to the next allow companies to define objectives and practices that gradually lead them towards performance excellence [START_REF] Machado | Framing maturity based on sustainable operations management principles[END_REF], [START_REF] Looy | A conceptual framework and classification of capability areas for business process maturity[END_REF]. According to [START_REF] Tesmer | Using process frameworks and reference models to get real work done (best practices report[END_REF], maturity models help companies to prioritise actions and define the type of improvement or "maturity" they need. In the CMM, the maturity of a practice is defined as the degree of process effectiveness and efficiency that reflects the capability of organisations to execute processes successfully [START_REF] Kaner | A capability maturity model for knowledge-based decisionmaking[END_REF]. Some authors have developed other maturity models, in particular based on organisational capabilities. In [START_REF] St-Amant | Aspects théoriques d'un cadre de développement des capacités organisationnelles[END_REF], organisational capabilities are defined as "the deployment, the combination and the coordination of resources, competencies and knowledge through different value flows to achieve strategic objectives". It is the potential that a company has to be efficient.

Moreover, organisational capabilities are considered as not being static; they can evolve along with their application and so are linked to learning.

[ [START_REF] St-Amant | Aspects théoriques d'un cadre de développement des capacités organisationnelles[END_REF] therefore propose a maturity model of organisational capabilities, which they define as "a descriptive and normative model of maturity levels through which the organisational capabilities of an organisation will go, as the organisation develops a structured and organised reflection on its operational modes by using and creating knowledge, by improving competencies of its individuals and by investing in resources". This model is used to assess, both quantitatively and qualitatively, the characteristics of an organisational capacity on a five-level scale, which has similarities with the five levels proposed in CMMI [START_REF] Ngai | Energy and utility management maturity model for sustainable manufacturing process[END_REF]:

• Level 1 (initial): corresponds to an ad hoc and chaotic organisational capacity, expressed in the performance of activities; processes are not clearly defined. The success of the application depends almost exclusively on individuals' efforts and competencies.

• Level 2 (description): corresponds to an organisational capacity, expressed and operated with defined and documented processes. This first systematisation improves the efforts, the competencies and the knowledge of individuals and of the organisation.

• Level 3 (definition): establishes the foundations from which the company will be able to work on improving its organisational capacities and maturity. The organisation has to allow for the repetition of processes and practices that have already been successful. Nevertheless, the processes are not measurable with precision and are only partially controlled.

• Level 4 (management): refers to a managed organisational capacity. The organisation identifies the competencies, knowledge and best practices, and integrates them into its action processes. The practices are documented and their results are quantitatively controlled and measured. The organisation manages its organisational capacities according to the data it has collected to evaluate its performance. When a process is quantitatively understood and controlled, it becomes predictable. At this level, standards and norms can be established and applied.

• Level 5 (optimisation): this is the level for optimisation and growth. It is based on a continuous improvement process that is facilitated by the feedback linked to the quantitative and qualitative control of key management processes. The organisational capacity is completely controlled at this level.

Most of the research works (cf. Section 2.2) on maturity models considers 5 levels of maturity very similar to those proposed by [START_REF] St-Amant | Aspects théoriques d'un cadre de développement des capacités organisationnelles[END_REF], with a description adapted to the field under study.

Lean Maturity Models

In the field of LM the number of studies proposing maturity models and frameworks has increased in recent years. Some of them aim at assessing the leanness of the company, others associate LM practices with other practices or approaches. [START_REF] Bento | Maturity of lean practices in brazilian manufacturing companies[END_REF] assess the Lean maturity of 90 Brazilian manufacturing companies, considering 38 Lean practices and five levels of maturity. They sent questionnaires to managers involved in the production, continuous improvement or quality activities of these companies. The study does not claim to guide companies in the implementation of Lean; it simply identifies practices with the highest (Customer Focus) and lowest (Problem Solving and Supplier Integration) level of maturity.

Some authors maintain that the Lean Enterprise Self-Assessment Tool (LESAT), developed by Lean Aerospace Initiative (LAI) at the Massachusetts Institute of Technology, is one of the most comprehensive framework [START_REF] Hallam | Company self-assessment of lean enterprise maturity in the aerospace industry[END_REF], [START_REF] Maasouman | Development of a lean maturity model for operational level planning[END_REF]. It takes into account 54 Lean Management practices, and for each of them a set of definitions is presented for every level of Lean enterprise maturity. These practices concerns different departments of a company (product development, production, supply chain, etc.) and different control levels (strategic, tactic and operational). Through this framework companies can decide which practices are worth developing to achieve more leanness, but it is not Lean Manufacturing oriented.

[ [START_REF] Maasouman | Development of a lean maturity model for operational level planning[END_REF] state that most of the maturity models provide a general direction and a company-wide roadmap and fail to monitor the effectiveness of Lean practices. They therefore propose a framework to assess the Lean maturity model adapted to the specifications of manufacturing cells. However, these authors point out that the organisation must provide an overall corporate Lean transformation plan as a prerequisite for the use of the proposed model.

Considering models combining Lean practices with other perspectives, based on a literature review, [START_REF] Zanon | Performance measurement and lean maturity: congruence for improvement[END_REF] develop a framework for assessing Lean and Performance Measurement System (PMS) maturity in organisations to take advantage of combined improvement efforts. They reviewed 20 Lean maturity models and 8 Performance Measurement System maturity models and correlated the parameters of both types of models. They found that none of the 35 parameters associated with Lean practices takes into account the working conditions of employees or health at work.

Adopting the same type of approach of reviewing the parameters of the maturity models in the literature, [START_REF] Tortorella | Lean manufacturing implementation: an assessment method with regards to socio-technical and ergonomics practices adoption[END_REF] propose an assessment method that combines LM practices and social-technical and ergonomics (SE) practices. According to these authors, the method allows for the identification of deficiencies related to the adoption of LM practices that may support the implementation of SE practices. Like [START_REF] Zanon | Performance measurement and lean maturity: congruence for improvement[END_REF], [START_REF] Tortorella | Lean manufacturing implementation: an assessment method with regards to socio-technical and ergonomics practices adoption[END_REF] do not consider the process in which the practices are embedded or in which they are intended to be implemented.

Synthesis

We note that the maturity models and frameworks proposed (except for [START_REF] Bento | Maturity of lean practices in brazilian manufacturing companies[END_REF] aim to identify the level of mastery in the implementation of the LM, and to highlight opportunities for improvement. These models are based on Lean Management and Lean Manufacturing practices.

However, these practices are embedded in the company's processes. In our opinion, and based on the CMMI, it is the ability to execute processes successfully while integrating LM practices that determines a maturity level. It is therefore important that the framework be process-oriented.

It means that the framework parameters should integrate one of the company's processes to be managed, followed up and improved, if necessary.

We also believe that it is important to integrate indicators (related to the process control and / or to performance) into the maturity model to guide managers more effectively in the use of the framework, to better track the organisational transformation, and to improve the progress process.

Finally, we believe it is also necessary to explicitly consider health at work in the implementation of LM in order to improve working conditions and develop employees' capabilities.

We therefore propose a process-oriented framework to assess processes' maturity from a LM implementation perspective and integrating human parameters, mainly those related to health. Some models from the literature have inspired us in the development of our framework, as we will see in section 4.

Research methodology

As stated in the introduction, the proposed framework is based on the combination of results of numerous industrial continuous improvement projects and bibliographic research.

The first author of this research paper is a senior consultant with 20 years' experience. He developed his knowledge and expertise initially from ergonomics to health at work, then lean manufacturing and industrial performance in recent years. The research reported here was carried out over a period of 10 years, from 2008 to 2017.

It included nine industrial companies, with on-site production lines and of different sizes (from 350 to 3,000 employees), different initial situations (in terms of economics and LM background or internal health-at-work situations), and different industrial segments (agri-food, automotive, energy, electronic, etc.). In all cases, the cited author was the project leader and steered them. These projects lasted between three and five years.

We can identify two main stages in our research methodology, in two specific groups of companies (Figure 1):

• an inductive stage: initially, we used a first set of observations based on the author's experience and compare these phenomena with a current bibliographic synthesis, to establish a first framework. This framework was tested on three LM projects to propose improvements based on new findings. This stage allowed us to formalise a second maturity framework and to test it on the ongoing LM projects

• a deductive stage: we applied the maturity framework defined in the previous stage to six other industrial companies. The management of these LM projects allowed us to test the proposed hypotheses and to make some local improvements, for instance in the definition of some parameters and their instantiation on the different maturity levels. This complete approach allowed the proposed maturity framework to evolve, up to the last version that is presented in the next section. The first and main objective of the proposed maturity framework, POMF-LM, is to be a tool which allows a manager (e.g. the person responsible for the deployment of the Lean Manufacturing approach) to assess, at a given moment, the company's capacities and capabilities to implement, execute and control a set of processes necessary to create human, financial and social value in a sustainable way. The second objective of this framework is to serve as a guide for defining an action plan for an improvement project in a Lean Manufacturing context. POMF-LM is composed of the parameters and of maturity levels considered. For each parameter, the expected process control is described for each maturity level. The maturity levels consider the intention (willingness to do it), awareness (knowing what to do) and know-how (competence) of the company. Thus, for each combination of parameter -maturity level, indicators are proposed, so that the company can verify its level of maturity. These indicators are related to the company's process control (PCI) and performance (KPI).

In this section we present the different levels of maturity considered in POMF-LM as well as its parameters and their overall evolution in terms of maturity. By means of an example of a parameter, we illustrate its description for each maturity level, as well as the associated indicators.

The entire framework is given in Tables 4 to 12.

Maturity framework levels

We propose a maturity framework with 6 levels that determines the improvement stages that an organisation has to follow. We draw on the research of [START_REF] St-Amant | Aspects théoriques d'un cadre de développement des capacités organisationnelles[END_REF] on maturity in organisational capacity, correlated with our own experience. We first add a level 0, which indicates that the company is not aware of what it does and has neither the knowledge nor the method to act and to improve. The company only reacts to intrinsic and extrinsic phenomena, thanks to the will and the motivation of some leaders but without capitalisation, and with a strong risk of loss of impetus and of acquired knowledge.

The different levels can be associated with a process of change management:

• Level 0: state of unawareness, since no knowledge or method is implemented, the actions are based on individual efforts; there is no process defined.

• Level 1: change of perception, acquisition of knowledge and methods concerning parameters management; the process has not yet been defined but the parameter is taken into account.

• Level 2: change the way of thinking, acquired knowledge is applied, enabling the development of know-how; the process is defined but not completely controlled.

• Level 3: change of behaviour, the formalisation of the processes allows the reproduction of improvement actions; the process is defined and controlled.

• Level 4: new habits, as the processes are totally under control, well documented and improved, naturally reproducible and controlled work habits are established, the approach is spread over the different sectors of the company; the process is implemented in most of the company's departments.

• Level 5: cultural change, total and collective appropriation of continuous improvement process; pursuit of perfection.

In the next section, all framework parameters are presented.

Maturity framework parameters

In this section we present the 19 parameters of POMF-LM. They are structured into 4 main processes as shown in Figure 2. These parameters represent sub-processes that has to be performed periodically to ensure a successful implementation of the main processes. These 4 main processes and their associated parameters have been defined from our industrial experience and literature review (cf. Section 3) as being the crucial elements to enable successful implementation of Lean with respect to health at work. The purpose here is not to present the description of each parameter for each maturity level (an example of instantiation of a parameter will be presented in the following and the whole framework is available in Tables 4 to 12), but to explain why we take it into account in the proposed framework and the expected evolution through this parameter. The proposed parameters have been compared afterwards with Lean and SE practices listed in [START_REF] Zanon | Performance measurement and lean maturity: congruence for improvement[END_REF] (Table 2) and in [START_REF] Tortorella | Lean manufacturing implementation: an assessment method with regards to socio-technical and ergonomics practices adoption[END_REF] (Table 3). From this analysis, we can conclude that our framework covers all listed practices and we went further by defining these parameters for all maturity levels with consistent indicators.

Improvement Management

The first main process groups together the parameters necessary to implement continuous improvement management in a sustainable way.

Improvement control (Table 4): within the proposed framework we define the steps required for a company to control an improvement management process, which at its more mature stage involves a strategic plan, at the tactical and operational levels. This plan must include all the company's departments and must be steered to guarantee the coordination of improvement actions (the setting up of a steering committee is part of a level of maturity). Authors such as [START_REF] Kaplan | The balanced scorecard[END_REF], [START_REF] Hines | Learning to evolve: a review of contemporary Lean thinking[END_REF], [START_REF] Lewis | Exploring soft versus hard factors for TQM implementation in small and medium-sized enterprises[END_REF][van Assen, 2018] stress the importance of defining a strategic improvement plan to clearly and simply link improvement initiatives to expected results. The Strategic Improvement Plan ensures consistency of actions linking long-, medium-and short-term actions to the results achieved at the organisational level [START_REF] Neely | Designing performance measures: a structured approach[END_REF], [START_REF] Bourne | Designing, implementing and updating performance measurement systems[END_REF].

Decision process (Table 4): this process is strongly linked to the previous one. It helps to define the decision-making structure of the company. It must ensure that decisions are based on the definition of precise objectives, the identification of decision variables, constraints and criteria to be optimised at the different decision levels. It must also ensure that the objectives of different decision levels are consistent with one another. Thus, it will allow the transmission of the improvement strategy from the general management to the departments, then to different operators, through action plans and quantifiable objectives within a realistic time frame [Liker, 2004], [Bhasin, 2012].

Moreover, and by acquiring more maturity, organisations can reverse the leadership pyramid and give more autonomy and responsibilities to operators and to proximity management in problemsolving actions. 4): this parameter concerns the control of PDCA (Plan, Do, Control, Act) implementation in the different management levels of the organisation to create an effective problem-solving dynamism. The research presented in [START_REF] Bortolotti | Successful lean implementation: Organizational culture and soft lean practices[END_REF] shows a relationship between the successful implementation of Lean and the use of problem-solving methods.

Solving problems (Table

Change management (Table 5): one of the problems often encountered in the implementation of the LM approach is the resistance to change, especially if the company has failed to implement this approach in the past. To avoid or improve this type of situation, companies need to set up a change management process by defining structured communication on the actions to be taken and the results obtained. The presentation of its actions must be contextualised in relation not only to the overall project, but also to the actions of the employees. [Rouse, 2005] argues that it is essential to have extensive knowledge of the organisational context and a complete understanding of existing systems to be able to transform them. Change management must be progressively implemented in all departments of the company and the improvement steering committee must be involved.

The next three parameters of this family are not processes to be implemented, but practices related to LM that should be managed in the company. We decided to integrate them into POMF-LM because we noticed in the projects carried out that companies had difficulties in applying or implementing these practices. We therefore integrated them into the proposed framework so that the managers could apply them gradually, to acquire experience and maturity and thus to ensure that the use of these practices is sustainable. 5): it is important to implement management standards to formalise processes, tools and practices related to management activities. Managers must define a rhythm of work and rituals that must be respected, according to their level of responsibility. 6): these concern the definition of work methods and rules. The work standards must integrate ergomotivity, which is developed in the Health Management parameter.

Management Standards (Table

Work Standards (Table

It implies a strong decrease of work activity variability, by directly improving quality and process performance and must be known by all operators.

Visual Management (Table 6): many companies apply 5S and its visual organisation of work areas, but many do not push visual management far enough. Yet this practice makes it possible to make objectives and priorities clearer, to avoid and identify malfunctions and to achieve results in all departments of the company. Several authors show that the results of a transformation are better when employees focus on specific objectives and when these objectives are perceived as achievable, which demonstrates the value of effective visual management [START_REF] Sim | Implementing Lean production systems: barriers to change[END_REF], [START_REF] Wan | Decision support for Lean practitioners: A web-based adaptive assessment approach[END_REF], [START_REF] Saurin | A framework for assessing the use of Lean production practices in manufacturing cells[END_REF].

Flow Management

This main process concerns the parameters related to the reorganisation and management of the physical and information flows, essential to the implementation of an efficient manufacturing system.

Physical Flow (Table 7): the pushed physical flow must be transformed/changed, considering the value flow, in a pull and synchronised flow, as recommended by the LM approach.

Plant Layout (Table 7): in parallel to the reorganisation of the physical flow, the layout of the workshop must be reconsidered and the workstations can be redesigned. It is usually necessary to change the layout of the workshop to change the physical flow. Furthermore, in the LM logic, companies must move their physical flow as far as possible towards one-piece flow. It is furthermore important to consider in the reorganisation(s) of the workshop(s) that the operators must not be physically isolated, to avoid stressful situations in case of problems or risks.

Supply chain Flow (Table 8): companies must also consider the evolution of their ecosystem, paying particular attention to their flows both upstream (suppliers) and downstream (distribution network, customers). These flows will also become more tense but associated with medium to longterm planning based on a MRP2 (Material Requirement Planning) logic to anticipate problems.

Information Flow (Table 8): this type of flow is sometimes neglected in the application of the LM approach, yet any decision is based on information. Thus, it is also very important to guarantee that employees have access to the right information, at the right time, and that this information is reliable. In this sense, the information flow must be clarified and structured to avoid unnecessary information loops. Therefore, procedures to ensure the quality of data and information must be introduced.

Human Resources Management

Lean paradigms always consider humans as the centre of any improvement. According to [Liker, 2004], the central position of humans in the Lean philosophy is more than a requirement, it is the key to a Lean enterprise's success. This main process takes into account the parameters related to this issue.

Employee Training (Table 9): many companies define training in relation to the department that requests it when a requirement is identified. However, it is important to implement a training process which is scheduled in line with the improvement planning, and which includes a follow-up of developed competences. This process must be structured, controlled and involve all departments of the company.

Temporary Work Management (Table 9): the organisation must have the same concern about temporary workers. A process that incorporates their training, appropriation of corporate culture and their integration into the improvement process must be defined and controlled.

Skills Management (Table 10): this parameter is directly related to the two previous parameters. Companies need to manage skills to be able to develop new ones in line with their improvement plan. It is therefore necessary to identify existing skills in all departments, to identify critical skills to define the skills that needed to be developed, and to manage the evolution of skills over time and in each department.

Health Management (Table 10): most companies do not consider their employees' health as a process that needs to be controlled and that can improve their performance. Some companies apply indicators related to occupational illnesses, and often manage employee health on a case-by-case basis. This issue is difficult to address in a LM improvement project. A process to manage it is necessary to identify the most common work-related illnesses in the company, to inform employees (including managers) of the risks of occupational illnesses and accidents and to train them in prevention methods, ergonomics and ergomotivity (performing the right movement in the execution of one's work). This process must also follow the evolution of these illnesses and the working conditions of the employees.

Social Relations (Table 10): this parameter makes sense particularly for companies located in countries where trade union actions are relevant, as is the case in France. We propose that the company considers its social partners to foster privileged communication with them concerning the objectives and expected impacts of the changes in the company, and thus to involve them directly in its transformation project. It is important for the social partners to be involved in problem-solving processes, for example to establish a constructive relationship in the implementation of the LM approach. We could integrate this parameter into other processes such as Change Management and Problem Solving, but the importance of these social partners for the smooth running of a Lean project led us to deal with it in a dedicated process.

Asset Management

This main process concerns the parameters related to the management of company assets. 11): this process concerns the application of an ergonomic approach. Managers must be trained in ergonomics and apply its rules and principles in the analysis of the arduousness associated with the work performed at each workstation. They will thus be able to make the workstation evolve and to take these aspects into account when the evolution of the whole production system is envisaged.

Work environment (Table

Equipment health (Table 11): this process concerns the management of the effectiveness and the maintenance of workshop equipment. It is about: a) managing then avoiding problems that lead to workstation (or even production line) stoppages; and b) carrying out the first level of maintenance by the operators and setting up a preventive maintenance plan.

Financial management (Table 12): in the context of a Lean improvement project, it does not mean implementing all the processes required by the financial department of the company. But it is about implementing a process that, in a first phase, ensures that the company's manufacturing activity generates a positive financial balance, and in a second phase, ensures that the company reinvests in its production system.

Synthesis

All the parameters -presented in this section -will help the company to deploy a necessary process to reach maturity in terms of management, decision-making and performance control. This is important for the successful LM implementation, as the evolving maturity of these parameters is what drives the change, organises the value chain, controls competency and manages resources. All these points will directly or indirectly act on the overall performance, in synergy.

As mentioned above, in POMF-LM, a clear description of maturity is presented for all parameters at each maturity level, as well as for process control indicators (PCI) and certain key performance indicators (KPI), which must be measured to validate the level of maturity. A description of all the parameters for each maturity level is given in Tables 4 to 12.

Experimentation

As indicated in Section 3, much of our research is based on experimentation in 9 industrial companies, carried out in two different stages of our research methodology. In this section we present the experiment performed in the company "Moulin de la Marche". It was carried out with the first complete formalisation of the maturity framework as presented here, during the second stage of our methodology.

Our objective is to illustrate the application of the POMF-LM in an LM improvement project.

To do so, we present some of the actions implemented during this project, to provide an overview of the means that have allowed the evolution of the company's maturity. Our intention is not to describe all the actions carried out, nor to justify the action plan in detail.

Use-case description

The studied factory "Moulin de la Marche", located in the west of France, has 350 employees and produces smoked salmon. It belongs to a food processing industrial group consisting of 60 plants with a total of 10,000 employees. This industry was characterised by low gross profits, high variability in raw material costs and a high degree of work arduousness. The management system and the industrial organisation system were based on the silo principle, meaning that the organisation was divided into workshops (shipping, fillet preparation, smoking, etc.) without any communication or transverse cooperation. Performance measurements were mainly quantitative and carried out per workshop. Finally, problems were solved individually by a quality department which imposes its processes. This plant was studied and assisted between 2008 and 2013, with the objectives of increasing its competitiveness and reducing workstation arduousness, to maintain employment sustainably. The company's economic context changed between 2008 and 2010, with stronger competition and an increase in the cost of raw materials. As far as human resources are concerned, nothing particular happened during this period, except that the population aged and some operators were not able to remain at their workstations for full shifts due to loss of physical capacity.

Evaluation method

The steering committee, consisting of the company's management committee and the head of maintenance, was first trained in all the concepts and principles included in the proposed framework.

Note that, in general, the steering committee should be made up of managers representing the parameter families. This global training lasted between 6 and 8 days and focused on the main concepts of the POMF-LM. The committee assessed the company's maturity four times during the project (in 2008 -Figure 3, 2010 -Figure 4, 2011 -Figure 5 and 2013 -Figure 6), and was assisted for the first assessment only. The frequency of maturity framework assessments was scheduled according to the stages of the improvement project. An assessment was carried out not only at the beginning of the project but also at each important step of the way, as the project evolved with the company's improvement. More importantly, it certified the implementation of concrete management and control of all processes with PCI and KPI measurements.

Each evaluation was carried out by a duo, to create a constructive and shared dynamic, and to highlight the diversity of perceptions. Each time, each duo of members of the steering committee presented their evaluation. Any shortcomings concerning the different perceptions required argumentation, to reach a global and shared consensus. The advantages of this procedure are as follows:

• it is a way for all members of the steering committee to share their perception based on facts;

• it allows a maturity level to be placed on an improvement scale, thus giving the steering committee a reference point in the progress to be achieved;

• the progress level thus defined creates a process of motivation and the PCIs and KPIs measured help in this sense;

• it highlights the company's strengths and weaknesses, so that the steering committee can define the development strategy more clearly and precisely.

The steering committee carried out all the evaluations during this project, with no changes in membership. The only difference at each stage was in the definition of the duos that could change, for the sake of better information sharing.

Initial situation in 2008 and first proposals

The company's initial situation was assessed and the result is shown in Figure 3. The following paragraphs provide details on the evaluation of certain parameters. The maturity level of the "Work Environment" parameter was assessed at level 1. Even though the plant had little knowledge of ergonomics, some attempts to improve workstation ergonomics had been made in the past. Unfortunately, these actions did not have a real impact on working conditions, and the need for progress in this area was perceived within the company.

The maturity of the "Health Management" parameter was also assessed at level 1. The plant had no knowledge of the Ergomotivity approach, but the need to develop operating modes for each workstation, consistent with the dynamic behaviour of the operators, was already perceived.

Moreover, although absenteeism was increasing strongly (since it was also beginning to affect the young population of operators), no causal relationship between absenteeism and the effects of the arduousness of the workstation was identified and, above all, none of the participants had the ability to identify it. At that time, there were no relevant indicators or occupational health management processes that could help managers make this assessment.

The maturity of the "Work Standards" parameter was assessed at level 0. There was a high variability in work methods due to uncontrolled work. In addition, the learning processes were long and significant differences in the teaching of working methods were identified. For instance, the morning team developed a fillet preparation method that differed from that of the afternoon team, without any specific reasons. Additionally, some operators on the morning team were declared medically unfit to perform certain operations. During this first audit, the lack of work standards was identified as one of the main causes of production variability and the lack of control over working methods was the main cause of certain physiological constraints.

Project and company maturity evolution

Considering this initial assessment, a large number of actions could have been proposed. However, the company was not ready to implement all of them and its resources were limited. It was therefore decided to focus the project on work standardisation and work environment parameters during the period from 2008 to 2009, and on the improving other parameters from 2009 to 2010. Note that at the beginning of the project, the priority was not to enable the company to carry out a LM improvement project independently (without the help of the consultants), but to get the company out of a critical situation.

After this decision, the first step was to identify and validate relevant indicators relating to the work environment parameter. The manager, responsible for this action, defined indicators of arduousness to manage the employees' physical ageing as well as possible. At that time, there was no one in the company who could evaluate the company with regard to physical risks and the inability of an operator to perform the right gesture at a work situation. The company could only identify the increase in absenteeism, but this would not be enough to understand, measure, correct and above all prevent the causes of this absenteeism.

The performance indicators that were employed were as follows:

• Scaling of workstation arduousness,

• Number of complaints per workstation,

• Number of RSI (Repetitive Strain Injury) reports by workstation,

• Cost related to absenteeism for physical risk,

• Number of near-accident reports,

• Accident severity rate and frequency rate.

The second step was to implement a KPI control process. For instance, the number of complaints, an important indicator that expresses (implicitly) the level and quality of problems mentioned by employees, was difficult to measure. There was nowhere that employees could freely report their physical problems. Therefore, the steering committee decided to create the position of Head of Infirmary and Prevention. The missions of this new post were:

• to control health management and work environment indicators,

• to assist employees in situ,

• to support managers,

• to lead ergomotivity actions and to implement gestural work standards.

The third step concerned the training of all managers in ergonomics and ergomotivity.

This changed the level of perception and launched the change management process initiated by the steps to improve working conditions. The shipping workshop was one of the first to be transformed, because this workshop really required attention to the operators' gestures and ergonomic aspects.

Finally, the prevention manager was trained in ergonomics, ergomotivity, standardisation, and control of indicators.He was then able to apply the training on the principles of ergomotivity by instructing operators. Standardisation actions were thus organised at each workstation in the plant between 2008 and 2009. At the end of this process, each of these workstations had a gesture work standard. In addition, each employee with a physical disability was assisted by the prevention manager.

After these actions, a new assessment was carried out at the end of 2010 to finalise this first phase of the project (Figure 4). Several partial evaluations had been performed the meantime to verify the impacts of the actions.

All the employees were really involved in this evolution; it was a phase of radical change that strongly mobilised all the staff and in particular all levels of management. A large number of workshops and training sessions (also concerning other parameters) were organised. As a result, the overall maturity was greatly improved in all parameters. However, the company still had shortcomings concerning Improvement Control and Solving Problems (e.g. control of the problemsolving process).

Based on this evaluation, the project priority changed to better organisation of the added value flows, and to improvement of workstation ergonomics and of control process.

At the end of 2011, we noticed a distinct decrease in the company's revenue. In the assessment carried out at that point (Figure 5), the decrease in the indicators of the maturity framework showed that the maturity acquired in 2010 had not lasted. This evaluation motivated the decision to launch investigations to correctly identify the roots of the problem and thus to find solutions. One of the most critical aspects concerned improvement management family, in particular change management.

The audit highlighted the fact that the parameters linked to improvement management and human resources management significantly decreased its maturity level between 2010 and 2011. After studying the problem, the steering committee took the decision to appoint a performance manager to lead the project and to move the improvement control process forward. As a result, two years later (2013) a major improvement was noticed in the improvement control process and in problem solving parameters through the framework evaluation (Figure 6). Each of the managers had really found his/her place and acquired strong operational skills in problem solving and local management, consistent with the new organisation of physical flows.

In terms of measured performance indicators, the company noted that during the period from 2010 to 2013:

• complaints and absenteeism for RSI (Repetitive Strain Injury) concerning employees under 30 years of age had been eradicated,

• health insurance premiums had been reduced by 50%,

Discussion

At the end of this project, a closing meeting of the project was organised to present the results and have a feedback from the managers involved. All participants agreed that this tool had contributed to:

• identifying the essential aspects (parameters) that needed to be controlled to carry out an improvement project,

• assessing the company's maturity concerning these parameters,

• guiding the company in defining (or modifying) the action plan.

For the managers involved in the project, the difficult situation experienced in 2011 showed that the proposed framework helps to identify the parameters that are at the origin of the problems encountered in the company, thanks to the measurement of the indicators associated with each parameter (and therefore their maturity). However, further analysis is needed to identify the root causes. In addition, this situation also demonstrate that the maturity acquired could be lost.

Therefore, the use of POMF-LM should be combined with a periodic audit process to be defined in relation to the company, especially its size and available resources.

The progress of the other improvement projects (in other companies -from 2013 to 2017) confirmed the usefulness of the proposed POMF-LM. Among these other companies, we can take the example of "Jean Louis Amiotte", which is a SME specialised in the Morteau and Montbeliard sausage production (leader of this market). This company had 150 to 240 employees according to seasonality, with a turnover of 40Me. After a 31-months project (between 2015 and 2018), almost all objectives have been reached, like an absenteeism rate that went from 3% to 0.98%.

On the other hand, in the closing meeting, the managers involved have highlighted that the framework helped them to better identify the relations between the proposed parameters in an improvement project, thus enhancing their overall vision of the company.

We noticed that a gain of maturity in a given parameter directly or indirectly impacts understanding of the other(s) parameter(s). For instance, the improvement control and solving problem parameters are related to all other parameters, the plant layout and physical flow also have an influence on each other, and so on. Thus, it is advisable to adopt a global approach regarding the evolution of the parameters, to ensure the effectiveness of an LM improvement project, instead of focusing on only a few parameters. A first lesson learned was that there should not be large differences between the maturity levels of parameters, for instance a gap greater than 2 levels between two parameters, to guarantee a dynamic between all the actors involved. Another lesson learned concerned a limit to the use of the proposed framework. We had found that the company had to reach a certain maturity level to be able to assess its level of maturity itself, without the intervention of an expert or consultant. Based on the experience from all the experiments, the Table 1 shows the minimum maturity level required for each parameter so that a company can assess its own maturity level.

Parameters Family

Maturity Level Improvement Management

Level 3 for all parameters Flow Management

Level 3 for all parameters

Human Resources Management

Level 1 for Social Relations Level 3 for other parameters

Asset Management

No required level for Financial Health Level 3 for other parameters

Table 1: Maturity level required for a company self-evaluation

Conclusion and further research

In order to simultaneously improve industrial performance and health at work in a context of LM implementation, we have proposed in this article a process-oriented framework for assessing company maturity (POMF-LM). POMF-LM assesses the level of a company's ability to manage the different processes required to implement a LM improvement project. In addition, the proposed framework can be used as a guide to help managers define improvement actions and control performance. The POMF-LM is composed of 19 parameters divided into 4 families (improvement management, flow management, human resource management and asset management). The parameters are instantiated on 6 levels of maturity.

This framework was first designed to provide a factual measure of the company's maturity levels. Each level of maturity presents a description of the control level expected for each process, and provides process control indicators and performance indicators to be measured and followed up. In this way, the maturity framework structures and guides the company's LM transformation.

It enables it to identify maturity level gaps between the actual current situation and the objectives, to highlight the sensitive parameters (responsible for these gaps), and to control processes and thus develop performance and health at work. It is important to note that the maximum maturity level for each parameter has been defined from the perspective of the implementation of the LM approach. Thus, the maximum maturity level is not necessarily ideal for all companies, as some aspects of this approach are not applicable to all contexts. For example, pull flow is difficult to apply to companies that face strong market variations. The most important point is therefore to define the levels of maturity to be reached in accordance with the company's strategy. The management standard is applied (limited perimeter).

Each action has to be followed by a deployment phase that integrates management standards to ensure stability

Each question asked at station level gives the opportunity to formalise management standards, so that the answer is unique and shared in the organisation and optimises the system overall

The management standard is implemented on all production lines.

Each question asked at the station and line level gives the opportunity to formalise management standards so that the answer is unique and shared in the organisation and optimises the entire system Each management activity at local and middle levels of the organisation is under a standard. The organisation financial situation is positive and its results exceed the industrial sector average results

The company invests in its production facilities to ensure the performance level

The organisation is able to self-finance its activities to ensure its economic growth

The company invests more than 5% of its total sales revenu in R&D

Figure 1 :

 1 Figure 1: Research methodology description.

Figure 2 :

 2 Figure 2: The 19 process-oriented parameters of POMF-LM.

Figure 3 :

 3 Figure 3: Maturity evaluation in 2008

Figure 4 :

 4 Figure 4: Maturity evaluation at the end of 2010, in comparison with that of 2008.

Figure 6 :

 6 Figure 6: Maturity evaluation in 2013, in comparison with that of 2011.

Table 2 :

 2 Comparison between parameters from[START_REF] Zanon | Performance measurement and lean maturity: congruence for improvement[END_REF] and the POMF-LM ones

	Parameters Family		Improvement Mgmt.			Flow Mgmt.		HR Mgmt.		Asset Mgmt.
	Proposed Parameters Communication and information	Improvement control	Decision Process	Solving Problem	Change Mgmt. √	Mgmt. Standards	Work Standards	Visual Mgmt.	Plant Layout	Physical flow	Supply Chain Flow	Information flow √	Employee Training	Temporary work Mgmt.	Skills Mgmt.	Health Mgmt.	Social Relations	Work Environment	Equipment Health	Financial Mgmt.
	system
	Overload for achievement of goals Management of staff turnover Ergonomics criteria for worksta-				P								√	√	√			P √
	tion design Workstation appropriated to work-																	√
	ers
	Workers' recognition and reward														P		P
	Teamwork and coaching Clarity in targets definition Risk alerts utilisation Search for good organisational cli-				√ √		√	√ √					I	I	I	I	I	√
	mate Search for the health and safety of															√		√
	workers Balancing among quality, scope,	√
	time and cost Anticipating and reducing the risk															√		√
	of incidents Appreciation for workers training Ergonomics recommendations as												√	√				√
	regulations Clear strategies, symbols and	√				√	√
	methods
	Regulation of technical, organisa-																P	P
	tional and human aspects Meetings for communication of				√
	projects

Table 3 :

 3 Comparison between Socio-technical and Ergonomic parameters from[START_REF] Tortorella | Lean manufacturing implementation: an assessment method with regards to socio-technical and ergonomics practices adoption[END_REF] and the POMF-LM ones

	Level 5: Cultural	change	Total and collective ap-	propriation of continu-	ous improvement pro-	cess				Perfection is sought			Management of the com-	pany improvement pol-	icy is implemented and	adapted at each level	(strategic, tactical and	operational).				PCI: Visual manage-	ment on all company	level; A3 of company	policy visible at each	level; Result and pro-	cess indicators visible	and updated	KPI: KPIs related to	implemented actions	The decision process is	deployed on all sites of	the company. An au-	tonomous management	set is constituted to	control improvement at	each site				PCI: Decision process	standards formalised for	all levels and sites; Vi-	sual management imple-	mented related to deci-	sions (for all levels) and	its results; Measure of	gaps with expected man-	agement standards at all	sites; Number of audits	at all sites	Suggestions from oper-	ators strengthen PDCA	flows from annual plan	at a rate of more than 25	per people and per year	PCI and KPI: The	same ones as at Level 4	for all departments
	Level 4: New habits		The processes are totally	under control, well doc-	umented and improved,	to that naturally repro-	ducible and controlled	work habits can be es-	tablished	Process is implemented	in most company depart-	ments	The steering committee	concerns all company de-	partments and can be	mixed up with the exec-	utive team					PCI: Deployment of vi-	sual management and	KPIs from the executive	team				KPI: KPIs related to	implemented actions	The decision process is	under control and de-	ployed for each deci-	sion level and depart-	ments. Decisions are	taken considering indi-	cators evolution and in	autonomous way (ac-	cording to the manage-	ment set level)	PCI: Decision process	standards formalised for	all levels; Visual man-	agement implemented	related to decisions (for	all levels) and its results;	Measure of gaps with	expected management	standards; Number of	audits		PDCA is used in the	daily management of op-	erations by all depart-	ments (or almost), and	used in the annual con-	trol of improvement ac-	tivities	PCI and KPI: The	same ones of the Level	3 for all departments,	Number of treated	PDCA for each man-	agement level for all	departments
	Level 3: Change of	behaviour	the formalisation of the	processes allows the re-	production of improve-	ment actions				Process defined and con-	trolled		The steering committee	is effective since one	year, the improvement	plan is controlled and	improvement actions are	coordinated. The results	can easily be perceived			PCI: Visual manage-	ment of KPIs						KPI: KPIs related to	implemented actions	A decision process model	is defined based on the	concept of an inverted	pyramid. An au-	tonomous management	set is implemented. The	process is controlled.	The results and process	indicators are identified		PCI: Decision process	standards formalised;	Visual management	implemented related to	decisions and results							PDCA is used and con-	trolled in the daily man-	agement of operations	and in problem solving	activities	PCI: PDCA standard	is formalised; Traceabil-	ity and capitalisation of	problems	KPI: Number of prob-	lems treated; KPIs re-	lated to problems
	Level 2: Change the	way of thinking	Acquired knowledge is	applied, enabling the de-	velopment of know-how					Process defined but not	completely controlled		A steering committee for	improvement control is	implemented. An im-	provement plan is de-	fined and improvement	actions are followed-up				PCI: Synchronised cal-	endar of executive team	and steering committee,	Management ritual of	executive team			KPI: KPIs related to	implemented actions	The decision process is	implemented from the	manager level (within a	limited perimeter), but	in a conventional way						PCI: Definition of de-	cision items (objectives,	decision variables, con-	straints, criteria)								PDCA is used by man-	agers in improvement ac-	tivities and in problem	solving ones, but not	controlled	PCI: PDCA indicators	implemented
	Level 1: Change of	perception	Acquisition of knowledge	and methods concerning	parameters management					Process non defined but	parameters taken into	account	As managers are trained	in Lean Management, it	generates an awareness	of the necessity to inte-	grate the Lean approach	in the company control.	Some improvement ac-	tions are implemented,	with no coordination	PCI: Number of execu-	tive team members that	are trained in Lean Man-	agement						Managers are trained in	the decisional process	and its structure. De-	cisions are clarified but	top-down, without stan-	dard process. Some indi-	cators exist				PCI: Number of man-	agers trained; Number	and consistency of indi-	cators related to deci-	sions							The managers are	trained in PDCA and	problem solving method			PCI: Number of trained	managers
	Level 0: State of un-	awareness	No knowledge nor	method implemented						No engaged process, no	structure		No implementation	of improvement con-	trol process. The	management is fully	conventional														Decisions are strongly	centralised, not shared	and without framework																			The daily constraints	use all resources
		Levels												Improvement Control																	Decision Process																					Solving Problems

Table 4 :

 4 POMF-LM description -parameter description from "Improvement Management" family (1/3)

	Level 5: Cultural	change	Total and collective ap-	propriation of continu-	ous improvement pro-	cess				Perfection is sought			New habits are mas-	tered and repeatable.	The culture has evolved	in the desired direc-	tion, the driving dynam-	ics of change is repeat-	able. The change is con-	tinuous				PCI and KPI: The	same ones as at Level 4;	Number of Audits
	Level 4: New habits		The processes are totally	under control, well doc-	umented and improved,	to that naturally repro-	ducible and controlled	work habits can be es-	tablished	Process is implemented	in most company depart-	ments	A change management	process is structured,	under control and ap-	plied by all managers,	with global and local	adaptations. The execu-	tive team meets periodi-	cally to build change and	so organises communica-	tion on results obtained	by the teams	PCI and KPI: The	same as Level 3 for	all departments; Com-	pliance with change	management standards	for all management	levels; Calendar of exec-	utive team information	meetings
	Level 3: Change of	behaviour	the formalisation of the	processes allows the re-	production of improve-	ment actions				Process defined and con-	trolled		The company has clearly	defined its project and	proposes a clear and ap-	pealing imagery of it; it	has structured a commu-	nication rhythm for em-	ployees					PCI: The same ones as	at Level 2; Change man-	agement standards are	formalised; Number of	information meetings				KPI: KPIs related to	main changes proposed	in the project
	Level 2: Change the	way of thinking	Acquired knowledge is	applied, enabling the de-	velopment of know-how					Process defined but not	completely controlled		The company defines	its project and proposes	and deploys a rhythm	of communication with	employees							PCI: A3 of the vision	and its path; Definition	of number and frequency	of information meetings
	Level 1: Change of	perception	Acquisition of knowledge	and methods concerning	parameters management					Process non defined but	parameters taken into	account	The managers are	trained in Change Man-	agement, and they are	involved in the project	communication inside	their department						PCI: Number of trained	managers							The managers are	trained in Management	standards. They start	procedures to describe	operating methods or	orientations when prob-	lems are too obvious
	Level 0: State of un-	awareness	No knowledge nor	method implemented						No engaged process, no	structure		The company is not clear	on its vision. An atmo-	sphere of uncertainty ex-	ists related to a lack of	communication by man-	agement on the future of	the company													The management has	no reference framework	to answer uncertainties.	Decisions are often in-	consistent
		Levels												Change Management																		Management Standards

Table 5 :

 5 POMF-LM description -parameter description from "Improvement Management" family (2/3)

	Level 5: Cultural	change	Total and collective ap-	propriation of continu-	ous improvement pro-	cess				Perfection is sought			The SDCA cycle is com-	pletely managed and	controlled by operators	and proximity managers											PCI and KPI: The	same as at Level 4 for all	production lines; Num-	ber of standards created		No anomaly can be	missed by anyone in	the company, whether	untrained or not, or	whether a manager at	any level or an operator				PCI and KPI: The	same as at Level 4 for	all company levels; Vi-	sual KPIs evolution on	problem solving
	Level 4: New habits		The processes are totally	under control, well doc-	umented and improved,	to that naturally repro-	ducible and controlled	work habits can be es-	tablished	Process is implemented	in most company depart-	ments	The work standards	are implemented on	all production lines.	Each operator knows	how to apply her/his	own standards and	those for downstream	and upstream related	activities. Standards for	activity volume inferior	to full process load exist.	For each standard, the	right gesture has been	defined	PCI and KPI: The	same as at Level 3 for all	production lines; Mea-	sure of standard effect	on activity variability	Work environment, ac-	tions, tasks, results are	clear and visual in all	production lines and de-	partments. No anomaly	can be missed by man-	agers nor operators			PCI and KPI: The	same as at Level 3 for all	company levels
	Level 3: Change of	behaviour	the formalisation of the	processes allows the re-	production of improve-	ment actions				Process defined and con-	trolled		The work standards in-	tegrate all aspects of	the actions that the	operators have to per-	form to ensure quality	production at a good	pace. The standards	integrate an ergomotiv-	ity approach and are ad-	hered to by the opera-	tors				PCI: Follow-up of train-	ing; Number of created	standards and audits		KPI: Results of audits	Visual management is	used to galvanise and	increase value of works	performed, with attrac-	tive presentation of indi-	cators. Visual Manage-	ment standards are for-	malised		PCI and KPI: The	same as at Level 2; Num-	ber of Audits; Satisfac-	tion rate of information	quality, of visual form	and of spots
	Level 2: Change the	way of thinking	Acquired knowledge is	applied, enabling the de-	velopment of know-how					Process defined but not	completely controlled		Work standard is im-	plemented but not com-	pletely controlled. Some	work rules are formalised	with a practical point-	of-view for the opera-	tor. The operators un-	derstand why Muri and	Muta are eliminated						PCI: The same as at	Level 1; Number of op-	erators trained in stan-	dardisation		5S is widely applied. An	audit process of 5S ac-	tions is implemented							PCI: Number of trained	managers; Number of 5S	actions and audits	KPI: Results of 5S au-	dits
	Level 1: Change of	perception	Acquisition of knowledge	and methods concerning	parameters management					Process non defined but	parameters taken into	account	The managers are	trained in work stan-	dard. Some working op-	erations are capitalised	on and formalised in	routings									PCI: Number of trained	managers; Number of	formalised routings			The managers are	trained in Visual Man-	agement. Some actions	are taken to make	explanations visual	and understandable.	5S actions exist. The	pathways are clean and	clear	PCI: Number of trained	managers; Number of 5S	actions
	Level 0: State of un-	awareness	No knowledge nor	method implemented						No engaged process, no	structure		There is no capitalisa-	tion on best practices																		There is no particular	visual tracking. Visual	display is not used to	create a motivating dy-	namics
		Levels												Work Standards																			Visual Management

Table 6 :

 6 POMF-LM description -parameter description from "Improvement Management" family (3/3)

	Level 5: Cultural	change	Total and collective ap-	propriation of continu-	ous improvement pro-	cess				Perfection is sought			All value flows are syn-	chronised and pulled					PCI and KPI: The	same as at Level 4										Synchronized produc-	tion in piece-to-piece	flow		PCI and KPI: The	same as at Level 4
	Level 4: New habits		The processes are totally	under control, well doc-	umented and improved,	to that naturally repro-	ducible and controlled	work habits can be es-	tablished	Process is implemented	in most company depart-	ments	All production lines be-	come value flows, with	synchronized and con-	trolled flows. A first pull	flow is implemented in a	value line	PCI and KPI: The	same as at Level 3; Vari-	ability control of prod-	uct quality; OEE								No operator works alone	and all workstations in-	tegrate a production line		PCI and KPI: The	same as at Level 3
	Level 3: Change of	behaviour	the formalisation of the	processes allows the re-	production of improve-	ment actions				Process defined and con-	trolled		The flow organisation	becomes value flows.	Flows are synchronized	and controlled			PCI: The value stream	mapping is defined	(VSM) with a target	vision				KPI: The same as at	level 2; Line balancing	schemas		In the areas where the	facilities are arranged in	function of the produc-	tion process stages, op-	erators are not alone	PCI and KPI: The	same as at Level 2
	Level 2: Change the	way of thinking	Acquired knowledge is	applied, enabling the de-	velopment of know-how					Process defined but not	completely controlled		A comprehensive view	of flows is defined. A	product-process matrix	is defined. Operators are	trained in the Lean ap-	proach	PCI: Visual product-	process matrix; Visual	flow mapping and as-	sociated indicators (lead	time, stock level, sur-	face, distance, takt time,	etc.)	KPI: The same as at	Level 1			Some facilities' layout	is defined in relation	to production process	stages	PCI and KPI: The	same as at Level 1; Num-	ber of facilities layout	in relation to production	process; Number of iso-	lated operators; Versa-	tility level
	Level 1: Change of	perception	Acquisition of knowledge	and methods concerning	parameters management					Process non defined but	parameters taken into	account	Managers are trained	in production flow and	Lean approach and	"tools". Some product	flows are synchronised	but pushed	PCI: Number of trained	managers						KPI: Lead Time; Prod-	uct quality; Productiv-	ity, Customer satisfac-	tion; Takt time	Managers are trained in	plant configuration and	production flow. Some	workstations integrate a	production line	PCI: Number of trained	managers	KPI: Lead Time; Prod-	uct quality; Productiv-	ity; Customer satisfac-	tion
	Level 0: State of un-	awareness	No knowledge nor	method implemented						No engaged process, no	structure		Physical flows are	pushed and organised in	different sectors															Workstations are organ-	ised by operation type	and operators can work	alone
		Levels												Physical Flow																	Plant Layout

Table 7 :

 7 POMF-LM description -parameter description from "Flow Management" family (1/2)

	Level 5: Cultural	change	Total and collective ap-	propriation of continu-	ous improvement pro-	cess				Perfection is sought			Production is synchro-	nised and well adapted	to the customers' need.	The improvement pro-	cess is well implemented	inside the company,	but it also integrates	the relationship with	suppliers and customers.	Medium-to long-term	problems are anticipated	by MRP planning									The process associated	with the information	flow is well implemented	and respected. It is in-	tegrated into the design	phase	PCI and KPI: The	same as at Level 4
	Level 4: New habits		The processes are totally	under control, well doc-	umented and improved,	to that naturally repro-	ducible and controlled	work habits can be es-	tablished	Process is implemented	in most company depart-	ments	The production is	smoothed over the	whole process (from	the customer till the	supplier) in all com-	pany. The value flow is	controlled					PCI and KPI: The	same as at Level 4; Re-	spect of planning	KPI: The same as at	Level 3; Customer and	Supplier satisfaction				All the stakeholders con-	cerned by the informa-	tion value flows have ac-	cess only to the informa-	tion needed to guarantee	their performance	PCI and KPI: The	same as at Level 3; Ad-	herence to process stan-	dards for each flow
	Level 3: Change of	behaviour	the formalisation of the	processes allows the re-	production of improve-	ment actions				Process defined and con-	trolled		The pull flow is con-	trolled. The production	is pulled by the customer	demand. The end prod-	ucts are produced every	day						PCI: Respect of logis-	tics contract		KPI: Respect of the	Logistic planning (pro-	duction and supply);	End product back or-	ders; component parts	back orders	Information flow is con-	trolled, laminar and or-	ganised considering the	value flows. Information	flow standards are for-	malised	PCI and KPI: The	same as at Level 2; Lead	time evolution; Informa-	tion flow standards for-	malised
	Level 2: Change the	way of thinking	Acquired knowledge is	applied, enabling the de-	velopment of know-how					Process defined not	completely controlled		Physical flows are pulled	by the customers										PCI: The same as at	Level 2		KPI: End product back	orders, component parts	back orders, Respect of	the upstream planning	considering the down-	stream requirements	A comprehensive and	clear vision of informa-	tion flows is defined	PCI: Visual information	flow mapping and asso-	ciated indicators	KPI: Lead time, Wait-	ing time
	Level 1: Change of	perception	Acquisition of knowledge	and methods concerning	parameters management					Process non defined but	parameters taken into	account	Managers are trained	in production flow con-	sidering the company	ecosystem (downstream	and upstream flows).	Some sub-assembly	parts are pulled by the	downstream flow				PCI: Number of trained	managers		KPI: End product back	orders; component parts	back orders				Managers are trained in	information flow tools	and reliability of in-	formation. The com-	plex information flows	are mapped	PCI: Number of trained	managers; Number of in-	formation flow mapping	KPI: Lead time
	Level 0: State of un-	awareness	No knowledge nor	method implemented						No engaged process, no	structure		The production and sup-	ply plan is based on a	pushed flow logic, apply-	ing the MRP method																	Information flows are	complex, sector-specific	and not clearly defined
		Levels												Supply Chain Flow																				Information Flow

Table 8 :

 8 POMF-LM description -parameter description from "Flow Management" family (2/2

	Level 5: Cultural	change	Total and collective ap-	propriation of continu-	ous improvement pro-	cess				Perfection is sought			Each colleague can	follow-up his/her pro-	gression and can propose	to his/her manager a	training process ac-	cording to the targeted	improvements	PCI and KPI: The	same as at Level 4; In-	dividual maturity level;	Individual level of skills										The temporary work-	ers appropriate the com-	pany culture, they fully	participate in the im-	provement process					PCI and KPI: The	same as at Level 4
	Level 4: New habits		The processes are totally	under control, well doc-	umented and improved,	to that naturally repro-	ducible and controlled	work habits can be es-	tablished	Process is implemented	in most company depart-	ments	The training process is	controlled by all man-	agers and standardised	with indicators on pro-	cess and results			PCI: Availability of	training indicators in all	sectors; Training plan	monitoring		KPI: Rate of people	trained according to the	training plan; Satisfac-	tion rate of trainings	followed; Results ob-	tained after trainings;	Gap measures with ob-	jectives	The qualification level	of temporary workers is	consistent with the ex-	pectations. The work	standards are known and	controlled by all man-	agers			PCI and KPI: The	same as at Level 3; Skills	indicators defined by a	matrix of skills
	Level 3: Change of	behaviour	the formalisation of the	processes allows the re-	production of improve-	ment actions				Process defined and con-	trolled		Manager(s) applies the	training process and	measures the results.	The training process is	controlled and standard-	ised, with a measure of	the results	PCI: The same as at	Level 2; Training process	standard visible; Avail-	ability of training indi-	cators	KPI: The same as at	Level 1; Number of pro-	cess audits and results						A qualification and in-	tegration process is im-	plemented with tempo-	rary employment agen-	cies. It is standardised.	There is a traceability of	temporary worker quali-	fication. The process is	standardised	PCI: Number of pro-	cesses formalised / num-	ber of temporary em-	ployment agencies; Ad-	herence to standards on	temporary worker moni-	toring	KPI: Number of process	audits and results
	Level 2: Change the	way of thinking	Acquired knowledge is	applied, enabling the de-	velopment of know-how					Process defined but not	completely controlled		A training process is	started. The company	take into account quali-	fication needs in a way	that is consistent with	its development strategy		PCI: The same as at	Level 1				KPI: Rate of trained	employees; Expected re-	sults for each training						An integration process is	implemented								PCI: The same as at	Level 1
	Level 1: Change of	perception	Acquisition of knowledge	and methods concerning	parameters management					Process non defined but	parameters taken into	account	Company starts to take	into account the qualifi-	cation needs related to	development objectives				PCI: Number of real	identified needs; Qual-	ification needs related	to development expecta-	tions	KPI: Number of train-	ings							A welcome is established	and an integration unit	exists							PCI: Number of wel-	comes / new temporary	workers; Number of inte-	gration courses followed	/ registered temporary	workers
	Level 0: State of un-	awareness	No knowledge nor	method implemented						No engaged process, no	structure		The training budget is	managed annually on	the basis of needs feed-	back																	No monitoring of tempo-	rary workers; no imple-	mented integration pro-	cess
		Levels												Employee Training																				Temporary Work Management

Table 9 :

 9 POMF-LM description -parameter description from "Human Resources Management" family (1/2)

	Level 5: Cultural	change	Total and collective ap-	propriation of continu-	ous improvement pro-	cess				Perfection is sought			The levels of multi-	competencies and flexi-	bility are managed, as is	the evolution of knowl-	edge on professions.	Skills standards are	updated when necessary		PCI and KPI: The	same as at Level 4 for all	employees							Each management level	integrates into its health	control the employees'	well-being at work				PCI and KPI: The	same as at Level 4 for all	management levels											Employees have the	opportunity to become	company shareholder,	and can receive divi-	dends	PCI and KPI: The	same as at Level 4;	Profit sharing level; Em-	ployee capital participa-	tion rate; Payment of	dividends
	Level 4: New habits		The processes are totally	under control, well doc-	umented and improved,	to that naturally repro-	ducible and controlled	work habits can be es-	tablished	Process is implemented	in most company depart-	ments	The matrix of skills and	skills evaluation process	are controlled for all	management levels and	departments. The ma-	trix of skills is visible	and accessible to each	concerned actor	PCI: The same as at	Level 3 for all manage-	ment levels and depart-	ments			KPI: Evolution of ma-	turity levels for all man-	agers	A health management	process is implemented	throughout the company					PCI and KPI: The	same as at Level 3 for	the entire company											The social and perfor-	mance issues of the com-	pany are addressed in a	constructive way	PCI and KPI: The	same as at Level 3; Em-	ployee satisfaction level
	Level 3: Change of	behaviour	the formalisation of the	processes allows the re-	production of improve-	ment actions				Process defined and con-	trolled		The skills evaluation	process is controlled and	standardised						PCI: Skills parameters	are described; Number	of processes standard-	ised; Number of audits	of skills evaluation stan-	dards; Results of audits	carried out by HR			The health management	process is controlled.	Experts are defined	as are their role and	objectives. The process	standards are formalised		PCI: The same as at	Level 2; Number of	work standards defined;	Follow-up of audits	concerning the work	standard application;	Follow-up of PDCA	projects related to	health indicators	KPI: Evolution of	health indicators; Avail-	ability rate of health	indicators; Audits	results	The communication pro-	cess integrating social	partners is controlled.	Members of social	partners participate to	problem-solving actions	PCI and KPI: The	same as at Level 2; Num-	ber of social partners'	members associated to	implemented actions
	Level 2: Change the	way of thinking	Acquired knowledge is	applied, enabling the de-	velopment of know-how					Process defined but not	completely controlled		Skills are identified and	evaluated. The eval-	uation process is im-	plemented but not con-	trolled				PCI: The visible matrix	of skills								A health management	process is implemented.	Experts are defined as	along with their role	and objectives.The indi-	cators are also imple-	mented and controlled	PCI: Percentage of	employees trained by	theme; Number and	qualification of indica-	tors					KPI: Evaluation of the	follow-up of the health	indicators control		A communication pro-	cess about change man-	agement is implemented	integrating social part-	ners	PCI and KPI: The	same as at Level 1
	Level 1: Change of	perception	Acquisition of knowledge	and methods concerning	parameters management					Process non defined but	parameters taken into	account	Skills are identified								PCI: Number of man-	agers trained in skills	management							Managers and employees	are trained in risk pre-	vention and ergonomics	and ergomotivity ap-	proaches. Indicators	concerning occupational	diseases are defined	PCI: Number of man-	agers and employees	trained; Number and	qualification of indica-	tors									The change management	process integrates social	partners	PCI: Social partners'	satisfaction level	KPI: Absenteeism rate
	Level 0: State of un-	awareness	No knowledge nor	method implemented						No engaged process, no	structure		The operating skills are	not clearly identified																No health indicator	is implemented and	followed up																		Social partners dis-	agree with the company	Negotiations project.	are difficult
		Levels												Skills Management																	Health Management																			Social Relations

Table 10 :

 10 POMF-LM description -parameter description from "Human Resources Management" family (2/2)

	Level 5: Cultural	change	Total and collective ap-	propriation of continu-	ous improvement pro-	cess				Perfection is sought			Implementation of peri-	odic audits to guarantee	the level of maturity and	the integration of the	ergonomics approach in	the product and equip-	ment design processes			PCI and KPI: The	same as at Level 4; Gap	between the prescribed	and the real; Managers	responsible for the in-	dustrialisation phase of	new product projects are	trained in ergonomic ap-	proaches and methods					Equipment run with no	hazard irrespective of	the production volume	required				PCI and KPI: The	same as at Level 4;	Number of preventive	maintenance standards	created,; Respect of	preventive maintenance	schedule; Percentage of	employees trained in	preventive maintenance	standards
	Level 4: New habits		The processes are totally	under control, well doc-	umented and improved,	to that naturally repro-	ducible and controlled	work habits can be es-	tablished	Process is implemented	in most company depart-	ments	The process of worksta-	tion arduousness scaling	is implemented in all	(or almost) production	lines. A manager is re-	sponsible for this pro-	cess, and ensures its per-	formance and its effi-	cient deployment	PCI and KPI: The	same as at Level 3 for all	production lines; Eval-	uation and evolution of	ergonomics benefits ob-	tained; Medical restric-	tions of aptitudes							Equipment management	process is controlled for	all production lines. The	first level maintenance is	done by operators and	the breakdown rate is	less than 1%	PCI and KPI: The	same as at Level 3;	Number of created	self-maintenance stan-	dards; Percentage of	employees trained to	self-maintenance stan-	dards; Audits follow-up	concerning compliance	with standards; Results	of these audits
	Level 3: Change of	behaviour	the formalisation of the	processes allows the re-	production of improve-	ment actions				Process defined and con-	trolled		The process of worksta-	tion arduousness scaling	is controlled by an ex-	pert manager (defined)	and she/he participates	in the ergonomics evalu-	ation. The process stan-	dards are formalised		PCI: The same as at	Level 2; Follow-up of im-	provements; Number of	work standards defined;	Follow-up of audits con-	cerning the work stan-	dard application		KPI: The same ones	as Level 2, Evolution	for all workstations pre-	sented in the ergonomic	level map	Equipment manage-	ment process is con-	trolled. Equipment	down-time generates	problem-solving actions.	Equipment management	process is standardised	PCI and KPI: The	same as at Level 2;	Response time; Indica-	tors of the maintenance	PDCA approach; Num-	ber of created mainte-	nance standards; Audits	follow-ups concerning	compliance with stan-	dards; Results of these	audits
	Level 2: Change the	way of thinking	Acquired knowledge is	applied, enabling the de-	velopment of know-how					Process defined but not	completely controlled		A process of worksta-	tion arduousness scaling	is initiated (within a lim-	ited perimeter)						PCI: map of worksta-	tion ergonomics level							KPI: The same ones as	Level 1, Infirmary visits,	Occupational diseases			Equipment management	process is implemented.	Equipment down-times	are trigerred for im-	provements			PCI and KPI: The	same as at Level 1; Re-	sponse time
	Level 1: Change of	perception	Acquisition of knowledge	and methods concerning	parameters management					Process non defined but	parameters taken into	account	Managers are trained in	the ergonomic approach	and methods. The first	actions are carried out	and the first indicators	set up				PCI: Number of man-	agers trained; Number of	actions carried out						KPI: Arduousness indi-	cators, Absenteeism rate				Equipments is re-started	by production operators	when hazards occur					PCI: Number of haz-	ards and accidents for	each piece of equipment;	Breakdown rate with ty-	pology; Hazard cause	KPI: Overall Equip-	ment Effectiveness	(OEE) of an equipment	or a production line
	Level 0: State of un-	awareness	No knowledge nor	method implemented						No engaged process, no	structure		No ergonomics-related	actions are implemented	in the company. There	are no indicators of	arduousness and work-	station ergonomics																	Equipment repairs are	performed when hazards	occur
		Levels												Work environment																						Equipment Health

Table 11 :

 11 POMF-LM description -parameter description from "Asset Management" family (1/2)

	Level 4: New habits
	Level 3: Change of	behaviour
	Level 2: Change the	way of thinking
	Level 1: Change of	perception
	Level 0: State of un-	awareness
		Levels

Table 12 :

 12 POMF-LM description -parameter description from "Asset Management" family (2/2)

According to[Porter, 1991], frameworks identify the set of relevant variables (related to the topic under study). It helps the analyst to better think through the problem by understanding the company and its environment. The theory embodied in frameworks is contained in the choice of included variables, the way variables are organised, the interactions among the variables, and the way in which alternate patterns of variables and company choices affect

• the company had generated annual profits of 1,500,000 e,

• the local managers had been boosted by the increase of their competencies and their responsibilities.

The project ended in 2013 with these results. Two years later, we came back in this company and could certify that:

• the improvements made during the project period were still real,

• the periodic maturity assessment was still applied.

These elements justify a sustainable transformation for this company.

POMF-LM has been tested, partially or completely, on several companies, in very different contexts in terms of economic strength, industry, size, country, etc. Its use in the context of a company's LM improvement project has demonstrated that a maturity level is not definitively acquired but requires continuous effort. The framework can nevertheless measure possible maturity decreases and guide the problem-solving process. To avoid significant losses of maturity, we recommend periodic use of this tool, for instance every 6 or 9 months (this subject have been discussed in [START_REF] Galichet | Comment proposer une méthode pour l'amélioration de la performance globale à partir d'une évaluation de la maturité d'une organisation?[END_REF]). The periodicity must be defined by the steering committee, and according to the size of the company and especially the means to be implemented to carry out these controls.

Concerning future work, we are going to define precedence rules between different levels of parameters. We have seen in Section 5.5, the maturity level of some parameters impacts the maturity progress of others. To guide POMF-LM users more efficiently, we think it is useful to define rules for the evolution of maturity between different parameters (e.g. the parameter P1 must be at maturity level 3 for the company to be able to shift the parameter P2 to level 2).

From a broader perspective, the framework does not define the improvement path. Future research could work on the definition of maturity objectives that are consistent with a company's strategy in terms of overall performance and resource allocation. Our aim is to establish a methodology that defines an improvement path on the basis of the initial and targeted maturity level.

Comments:

Value creation : The increase in value (added or created) being the basis of the lean approach, we consider that it must guide all the company processes Lean tools and method : Only some Lean tools are specified in the proposed framework Improvement Approach : All the parameters of the framework proposed are based on an improvement approach, but it is in the first parameter that this approach is specifically taken into account Flexible manpower and cross functional work : Skills management implicitly aims to develop these qualities

Product/Process quality planning : Work standards contribute to product and process quality, without focusing on planning

Perfection focus : This is included in the top maturity level of all parameters

Task-force preparation : This is implicit in the preparation of the proposed approach, with dedicated training for all stakeholders concerned Supplier integration : As this approach focuses on the core company, suppliers are only taken into account but not included

Change management and sustainability : The sustainability of the actions must be taken into account in all parameters

Overload for achievement of goals : The mental load is only partially taken into account in this approach, which is more focused on the physical load Ergonomics criteria for workstation design : Only at the top maturity level of this parameter


Morgane Bourhis

Pascal Perrier

Christophe Savariaux

Takayuki Ito

Takayuki Ito Compensatory

Compensatory movement of the tongue following a mechanical perturbation during speech (poster session)

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

Compensatory movement of the tongue following a mechanical perturbation during speech

Morgane Bourhis 1 , Pascal Perrier 1 , Christophe Savariaux 1 , Takayuki Somatosensory and auditory inputs play an important role in the production of speech sounds [START_REF] Guenther | Role of the auditory system in speech production[END_REF].

Somatosensory goal can be achieved during speech production even in the absence of auditory error [START_REF] Tremblay | whispering the vowel /e/ for 3,5 sec Tongue Perturbation : Step-wise pattern (1 N for 1 s) at TP in randomly selected 1/5 of the trials. Sensor locations: Tongue Tip (TT), blade (TB), and dorsum (TD), Upper Lip (UL), Lower Lip(LL), and Jaw (J)[END_REF].

The tongue showed quick compensatory response working for both stabilizing the tongue contour and maintaining the resultant produced sound [START_REF] Ito | Quick compensatory mechanisms for tongue posture stabilization during speech production[END_REF]

Introduction Sensory feedback for speech production

Compensatory movement of the tongue

Objective

Can the compensatory response of the tongue be induced in the absence of auditory feedback ?

Experiment

Results

Conclusion & perpectives

• The current compensatory response can be of somatosensory-basis.

• Further investigation (increasing the number of subjects, sound data and additional kinematic analysis) is required.

Funding

This work was supported by Agence National de la Recherché (ANR-21-CE28-0022) and National Institute on Deafness and Other Communication Disorders (R01-DC017439).

Contact

Morgane.Bourhis@Grenoble-inp.fr TT TB TP TP This compensatory response may be driven by somatosensory feedback alone.

Auditory masking (AM) and no masking (NM) conditions were tested in random order.

Horizontal tongue displacement at TB

Three ubj ' data were currently analysed. Data were aligned at perturbation onset and were averaged across trials.

Two of three participants showed compensatory responses, which were similar to the ones in Ito et al (2020) as follows:

• Consisting of two components, possibly passive and reflex components.

• Response latency

The responses were similar in auditory masking and no masking conditions.