Hillairet Dieter

Richard Guillaume

Bouchet Patrick

THE DUAL MANAGEMENT OF INNOVATION BY THE DECATHLON GROUP. A DISTINCTIVE STRATEGIC SYSTEM ON THE SPORT GOODS MARKET

Introduction:

Sports market is a global market which has been growing at an annual average rate of about 2 to 3% for over a decade [START_REF] Ohl | Les marchés du sport[END_REF]. Due to strong competition, brands are very dynamic [START_REF] Chantelat | Economie et management du sport[END_REF]. They constantly seek better positioning and new ways of gaining market shares [START_REF] Bouchet | Les marques de sport[END_REF]. In order to do this, these brands put more and more emphasis on innovation [START_REF] Hillairet | Sport et innovation -stratégies, techniques et produits[END_REF]. Following decades of domination by the major international brands and a permanent status quo between manufacturers on one side (i.e. Nike, Adidas,...) and specialized retailers on the other (i.e. in France, Decathlon, Intersport, GO Sport, Sport i 2000…), since the late 1990s, the industry has undergone a significantchange. Its structure has been transformed; new balances and new actors'statuses have appeared. Sports goods manufacturers become retailers by developing their own stores networks (i.e. Quiksilver, Lacoste ...), and retailersbecome sports goods manufacturers through the creation of subbrands under their control. Especially dynamic, these retailers create brand models that compete with the manufacturers, and through innovation they are able to provide consumers with technical and highperformance goods at affordable prices. But how do these companies, whose basic trade is distribution, manage to generate innovations considered as difficult and expensive? How did their R&D departments become so competitive? Is their innovation and ideas management system the key of their success? In this paper we are going to examine the case of Europe's leading company in this sector, the Decathlon Group 2, which has a constellation of own brands named "passionbrands". We will show how, starting from a vertical growth strategy, the Decathlon Group developed by creating new specialized brands and by launching a 'federator' innovation process as well as an R&D activity divided by sectors, not as a retailer owner of sub-brands, but as a manufacturer owner of ambitious and powerful autonomous brands. This strategy led to a dual system of innovation management, and finally, to a form of "variable geometry" management. This original organization finds its explanation in the fact that, beside its principal activity of retailer of sports articles, from now on, Decathlon Group has chosen to embark on a manufacturer's strategy with the announced ambition to make its very innovating passion-brands count inthe eyes of the consumers.

The vertical growth strategy of the Decathlon group: building a portfolio of powerful and innovative own brands

In contrast to an external growth scheme based on the creation of a portfolio of strong brands by purchase / acquisition as most companies usually do on many markets [START_REF] Ries | Les 20 lois du capital marque -Construire et conserver des marques fortes et durables[END_REF][START_REF] Aaker | Clés pour un bon choix des marques[END_REF][START_REF] Lewi | Branding management -la marque, de l'idée à l'action[END_REF][START_REF] Kapferer | Strategic Brand Management[END_REF][START_REF] Kapferer | FAQ -La marque[END_REF], the Decathlon Group has invented a model of business growth based primarily on the development of a portfolio made up of new own brands 3. At the same time, the group has developed, its own R&D department, an original management system of knowledge and innovations. In this way, the Decathlon Group is different from its main competitors such as Intersport and Go Sport which have not chosen to design and manufacture their own innovative and strong sub-brands. The latter has many own brands, but they are not built on characteristics related to technical performance or innovation [START_REF] Lebrun | L'évolution des recherches sur la distribution : conséquences pour le secteur des articles de sport[END_REF]. Today, the Decathlon Group has embarked on an upstream 4 vertical expansion without seeking to enhance the attractiveness of its sales outlets. By creating specialized brands that directly compete with international sports brands, the group seeks to control the market from the top (making faster, better control of prices...), while maintaining its position as a leading French specialized retailer. As is usually the case with all big international companies, this strategy asserts its wish to"control" the whole upstreamdownstream value chain to ensure better profitability [START_REF] Aaker | Building Strong Brands[END_REF]. However, when one retailer "controls" the whole channel, we notice an impoverishment of its offer along with a decrease in the number of referrals due to better coverage of its profitable brands. In its stores that focus on "in-house" goods produced by "passion-brands", the Decathlon Group retains much better margins. And, in order to make their conquest of the market successful, each new passion brand is given an autonomy variable from one brand to another in terms of R&D, budgets, and human resources. With a 2007 sales turnover of 4,476 Md€, including 56.60% realized outside of France, with more than 400 stores and more than 40,000 employees on the payroll, the Decathlon Group is a company which is involved in a true strategy of "expansion intrapreneuriale" whose mainstay is the constitution of a portfolio of new brands, not only able to launch new lines of products on the market but also able to durably transform a whole market segment. In 2008, these new sport brands were: Quechua, Kipsta, Domyos, Geologic, Aptonia, Inesis, Wedze, Tribord, Kalenji, b'Twin, Géonaute, Fouganza, Artengo and Oxelo. Each one of them is positioned on a precise sporting branch of industry: b'Twin, for example, is specialized in mountain bikes and road bikes; Wedze in boardsport on snow, and Kalenji in walking, running and cross-country running. Together, these "passion-brands" make the Decathlon group one of the first ten world's manufacturers of the sector behind Quiksilver, Nike, Adidas, Timberland, Columbia, Salomon, The North Face and Patagonia. By giving an autonomous operation and R&D (variable depending on the case) to each "passion-brand", the group's ambition is to acquire specialized brands capable of lasting shine on the international scene. Each one focuses its resources on a number of priorities and rationalizes the human and material resources needed to launch innovative goods. As a result, in 2008, no fewer than 12 new goods were rewarded with several design prizes (IF Design Award; Reddot Design Award & Design Observer). If the whole competitive advantage of Decathlon was based, until now, on the attractive prices of its sub-brands (but to the detriment of the performance of the products), the group's new objective is a rapid rise in technical performance through its innovative "passion-brands" with the aim to match exactly the expectations of sports enthusiasts. Even premium products are being studied, whereas they were previously reserved for specialized and old brands like Eagle, Lafuma (outdoor) or Helly Hansen (sailing & boating). "The Decathlon example is interesting to follow for it shows that companies can pass from one policy to another. For twenty years, the company has been following a single brand policy which, given the success of the scheme, has created an unexpected effect: the brand is almost 'soviet'. Everyone wears Decathlon goods and the brand has become a sign of standardization.

3. Even if, recently, the company also took the way of the external growth : indeed, the group bought, in 2008, the company Simond, a French brand specialized in the manufacture of ice axes, cramps and snap climbing hooks belonging to Wichard, the world specialist in fittings for pleasure boats. 4. The term "integration" does not seem, in the species, the right term; the term "expansion" seems more suitable.

With the strong reactivity that characterizes it, the company decided to change policy overnight and, from now on, to grow under specialized own brands anywhere in the world" (Kapferer, 2006, p. 185). Finally, the Decathlon Group follows the strategy of a big company willing to increase its market share by seeking to enter high margin segments [START_REF] Michel | L'extension de gamme verticale : clarification du concept[END_REF], although it was rather forced to do so. Indeed, the solution of sports specialized superstores -invented by Decathlon and successful either in France or in Europe -is a failure in countries where consumer patterns are different. Not to mention that, on some markets, particularly in the United States, there are situations of quasi-monopoly on behalf of local retailers (barrier at the entry) which cancel any thought of expansion of a newcomer, even a big one. Therefore, to become a producer instead of being only a retailer, has not only been an economic necessity but also a quasi-obligation in order to develop. On a market where the technicality of the products and the technological progress are powerful consumption levers, the competitive success of specialized brands will inevitably require the development of an innovation and creativity management system particularly productive and efficient. To take up this challenge, the Decathlon Group has implemented pioneering strategies that are likely to outdo the strategies of leading brands with much higher marketing, communication and sponsorship budgets. For example, if the "passionbrand" Tribord or Quechua develops today a policy of new products similar to that of international sport brands, it also chooses a widening spectrum of customers with sectional positionings, ranging from the first price ranges (the X-basic swimming goggles of Tribord are sold 3 €) to virtually premium ranges. This rise reflects a new step in the development of the group brands. At the same time, it is a challenge to offer consumer goods that are, on one hand, at the best quality-price ratio, and on the other hand, the result of advanced studies in the field of ergonomics, design, biomechanics, physiology or choice of materials. In order to obtain, for each of its "passion-brands", products as technically advanced as those of the best sports brands, the Decathlon Group must seek for the excellence in its R&D activities, particularly in the innovation process.

A federative innovation process and a R&D activity divided into sectors

Within the framework of many and various approaches, much authors have been interested in innovation processes : from the viewpoints of economicv changes and progress [START_REF] Schumpeter | Business Cycles, A Theorical, Historical and Statistical Analysis[END_REF][START_REF] Freeman | The Economics of Innovation[END_REF][START_REF] Kline | An Overview of Innovation[END_REF][START_REF] Dosi | Technological Paradigms and Technological Trajectories: A Suggested Interpretation of the Determinants and Directions of Technical Change[END_REF]Amendola & Gaffard, 1988, etc.), of social and organizational changes [START_REF] Rothwell | The Handbook of Industrial Innovation[END_REF][START_REF] Chandler | Organisation et performance des entreprises[END_REF]Callon, 1994, etc.), or from the sociological and managerial viewpoint [START_REF] Crozier | L'acteur et le système[END_REF][START_REF] Mintzberg | Structure et dynamique des organisations[END_REF][START_REF] Akrich | À quoi tient le succès des innovations -premier épisode : l'art de l'intéressement[END_REF]Alter 2000, etc.). But whatever currents and theoretical origins, the innovation process shows nevertheless a dual permanent feature. First, it is an integral part of the goods launched on the market, and thus, implicitly, of their success (or unsuccess) with users. Then, chronologically, the process is always the same: gestation, development and diffusion. If, in the sports industry, the issue of the diffusion of innovation has been approached under the technological angle, in particular through the diffusion of new materials [START_REF] Desbordes | Diffusion des matériaux, changement technologique et innovation : analyse et étude de cas dans l'industrie du sport instrumenté[END_REF], on the other hand, the issue of the production of ideas, of creativity and procedures, more generally the upstream part of the innovation process, has never been studied with specific depth [START_REF] Hillairet | Etat des recherches sur les innovations du secteur des sports et des activités associées[END_REF]. Thus, our study will focus on the R&D of the Decathlon Group, especially on how innovative ideas are created and managed. According to us, the analysis of the innovation management in this company is part of the prospects of [START_REF] Akrich | À quoi tient le succès des innovations -premier épisode : l'art de l'intéressement[END_REF] to make progress in the art of managing innovations: understanding the mechanisms by which innovations succeed or fail to develop principles that serve as guide to action. To a great extent, the success of the Decathlon Group innovations and"passion-brands" depends, first of all, on an excellent understanding and coordination between the various components of the company involved, but also on an atypical innovative projects management system. With regard to the emergence and implementation of innovative ideas, whether at the individual or the organization level, the genesis of new solutions has always to go through a succession of identifiable informal and cognitive steps [START_REF] Deschamps | Les maîtres de l'innovation totale[END_REF] that widely participate in the mechanisms of creativity [START_REF] Moles | Créativité et méthodes d'innovation[END_REF]Prost, 1995). This progression in the upstream part of the innovation process is indeed the core of the discovery step (Ait El-Hadj, 1989) and of the R&D in medium to large organizations, but also the core of the business project in smaller structures [START_REF] Burgelman | Inside Corporate Innovation[END_REF]. If this progression depends on the knowhow, the perception, the value systems of the company and on the quality of its innovative behaviour, it also depends greatly on the ability to innovate of the people involved in new goods development projects [START_REF] Robinson | L'entreprise créative -comment les innovations surgissent vraiment[END_REF]. Indeed, the steps of creativity that structure the start of any innovative project are largely determined by the creative skills and behaviours of consumers [START_REF] Kao | Entrepreneurship, Creativity & Organisation[END_REF][START_REF] Amabile | A model of Creativity and Innovation in Organizations[END_REF]. On the other hand, if it is no longer necessary to prove the role and the importance of the creativity management in the success of innovations [START_REF] Heunks | Innovation, Creativity and Success[END_REF][START_REF] Fitzgerald | Best Practice Creativity[END_REF]Brabandère, 1998), does this creativity management constitute a competence factor in the success of a company? In the case of the Decathlon Group, some indicators appear to be moving in that direction. In companies, innovation is driven by a proactive management of ideas that would include three distinct steps: first of all, a step of fertilization, then a step of sowing of the new ideas, an lastly, a step of incubation [START_REF] Deschamps | Les maîtres de l'innovation totale[END_REF]. The innovation process implemented within the Decathlon Group follows this modelling. It also divides into three great steps: the upstream step (a), the project step (b) and the marketing and communication step (c).

Methodological elements of research

On the methodological level, this study about the innovation management within the Decathlon Group is initially based on studies about the sports industry innovations [START_REF] Desbordes | Diffusion des matériaux, changement technologique et innovation : analyse et étude de cas dans l'industrie du sport instrumenté[END_REF][START_REF] Desbordes | Innovation management in the sports industry: lessons from the Salomon case[END_REF][START_REF] Desbordes | Empirical analysis of the Innovation Phenomena in the Sports Industry[END_REF]Chantelat, 1992;[START_REF] Hillairet | L'innovation sportive, entreprendre pour gagner[END_REF][START_REF] Hillairet | Sport et innovation -stratégies, techniques et produits[END_REF][START_REF] Hillairet | Etat des recherches sur les innovations du secteur des sports et des activités associées[END_REF], about the sports markets and industry [START_REF] Wolsey | Understanding the Leisure and Sport Industry[END_REF][START_REF] Ohl | Les marchés du sport[END_REF][START_REF] Mullin | Sport Marketing, Human Kinetics[END_REF][START_REF] Scully | The market structure of sports[END_REF][START_REF] Stotlar | Vertical Integration in Sport[END_REF] and about the sports brands [START_REF] Bouchet | Les marques de sport[END_REF]. Then, it is based on the expertise on the new products marketed by the Decathlon Group "passion-brands" since 2004. A thorough analysis of articles taken from professional reviews (particularly directed towards the industrial design and the sports articles market) usefully supplemented the knowledge of the company's innovation management. Lastly, this study is based on a research carried out by [START_REF] Richard | The Management of Sporting Innovation at Decathlon. Between Rationality and Chaos[END_REF] who interviewed the Director of the innovation of the Decathlon Group "passion-brands", Irwin Wouts. On this last aspect, the interview as collection method of primary data was chosen because of its absence of formalism. According to the authors, this method, not very directive, seemed more adapted to an executive officer unfamiliar with more sophisticated techniques. By letting the interviewee structure his answer, it is relatively easy to understand its logic before rationalization a posteriori. Moreover, the choice of the interview procedure makes it possible to establish a trust relationship with the interviewee so that he can speak more easily about the innovations developed by its company. a. The upstream step called internal step of vision, aims to identify opportunities for new targets (customers and market segments), new sales approaches (i.e. the launch of a national campaign of advertising spots for the Wed'ze skis and snowboards, the Quechua Forclaz Light polar, the Kalenji Deefuz T-shirt or the b'Twin bicycles) and new marketing approaches (i.e. the launch of websites such as www.prêt partez.decathlon.com where consumers have the opportunity to try more than 200 sports outfits for girls and boys on virtual models). In the company, this upstream step finds its concretization in 2-days creativity workshops gathering designers, R&D engineers and people in charge of marketing. Each workshop gives birth to 200 to 300 ideas of products or improvements (a few of which only will be taken into account). According to Irwin Wouts, director of innovation of the Decathlon Group "passion-brands", this step allows to "set relevant targets and high potential for innovation". In this process, the definition of the need according to a specific and latent use is essential to start the development of a new good. The listening of the customers, the feedbacks coming from the shops and the observation of sportsmen in the field, are the missions assigned to the product manager who will have to draw up the specifications. Then, in collaboration with advanced research and designers, the process engineers and the components engineers of Decathlon take over to establish the technical specifications (functional definition, materials, assembly processes, etc.).

b. The project step is characterized, first, by a strong creative Spirit order to find innovative ideas that are achievable within a reasonable price. This second step incorporates all Decathlon R&D activity such as scientific research programs and design and ergonomics studies. If these studies are conclusive, the head of the prototyping industry will make a first prototype that is subjected to "torture tests" in a laboratory then to the "testers club", a panel of customers, high-level athletes and people from the company staff(the "decathletes"). Chosen for their skills, their level of expertise and their critical mind, they have to monitor the quality and safety of the future product. The final prototype will be made after intensive use tests and the final technical specifications will be established. Then, the various offices of production, in France and abroad, will take over. The mass production of the products will be carried out by a Decathlon subcontractor who will be responsible for the supply of components, the quality of the series produced, the delivery in due time to the different logistic platforms of the group, and so on.

c. The marketing and communication step is the third step of the Decathlon innovation process. It encompasses both the implantation of the goods in stores (merchandising) and the definition of a media plan to be implemented. Depending on the nature of the projects, the importance of these three stages may be variable. While some projects will be inspired by the creativity of specialists and goods experts of the Decathlon Group, others, on the other hand, will be triggered by opportunities given by the observation of the markets and changing practices. According to P. Freychat, the Decathlon R&D Director, if we look at the very successful innovations of these last ten years (Flex concept, backpack Symbium, bra Topping Bra, Self Heat gloves, Supportive tights…), inspiration comes mainly from the observation of the use and simplification of the use like the b'Twin bicycle or the 2 seconds tent. Besides, the categorization of innovations invented by Decathlon is based, along with the goal of technical improvement, on this desire to simplify the use (figure 1). Eventually, the process varies according to the nature of the project and its actual intentionalities. But in any case, the project managers of the Decathlon Group try to "feed" the process both in quantitative (more plans for new goods are put in parallel to create a positive collective emulation) and qualitative modes (generation of many ideas with high growth potential 5). Many ideas come from the field of action. Staying in touch with places of practice, listening permanently to the sportsmen, setting a particularly dense network of technological and scientific observers and partners eventually determine a rather high threshold of creativity. Among the competitors, this creativity can be stimulated in different ways.

At Nike for example, ideas and opportunities to develop new goods germinate in the "Innovation Kitchen". It is in this unique place, located on the Nike campus, that were born most of the ideas underlying the biggest commercial successessuch as Michael Johnson's golden spikes, Cathy Freeman's wetsuit, or all Air Jordan models produced since 2001. The concentration of the whole of Nike's creativity in an only place is the natural outcome of the increasing business of the U.S. sports giant (basketball, football, athletics, horseback, etc.), the direct effect of which is to reduce the resources allocated to design new goods. If tens of millions dollars have been spent for the "Innovation Kitchen" since the beginning, approximately 90% of ideas that are experimented are never taking shape. At Nike, one prefers having a great deal of ideas in order to retain only the best ones. The resources invested in innovation and R&D by the American firm have no equivalent in the world.

Within the Decathlon Group, the categorization model of innovations is based on the positioning of each new good according to two criteria which are a better use (vertical axis) and a better technique (horizontal axis). Category 1 innovations being the weakest in terms of impact on the use and technical rupture, they are primarily improvements. With this category, we are no more in the field of the incremental improvement. On the other hand, category 4 innovations are the one the technology of which manages to modify the sportsmen's behaviours greatly and on a long-term basis. The concepts are very innovative even "revolutionary". * The categorization of Decathlon's innovations comes from an evaluation carried out by the authors of the paper.

Since its creation in 1976, the Decathlon Group has bet on a selective innovation in order to offer highperformance sports items thanks to the competence of its Research Center. But, unlike some major sports brands, the innovation culture of the Decathlon Group does not only focus on the material and technological dimension (processes, materials...). On the contrary, since 1997, the group has developed a tool, the Decathlon Research Center, the objective of which is to study the human body in motion. The studies made there are used to improve health, safety, comfort and pleasure of people practising a sport. In total, nearly 300 engineers and researchers work in the field of engineering and innovation. For more efficiency, the R&D Research Center is structured on the mode of concentric radiation. The first circle consists of a hard core of about thirty full-time specialists in three areas: anthropometry, biomechanics and thermic physiology. These three fields cover roughly 80% of the Decathlon Group R&D. Around this core, there are three additional circles. Firstly, a team of a dozen PhDs working on specialized topics during the time of their thesis (3 years, in general). Secondly, a team of students coming from engineering schools and from the university (2nd cycle -master) works on projects during six months. Finally, the third circle of skills consists of forty partner institutions: university laboratories, engineering schools, technical centres (i.e. the Technical Center of Leather and Footwear: physiotherapists, podiatrists, doctors...). The innovation process efficiency will get most of its substance out of this perfect union between these various circles of skills. Around this concentric and centralized operation of R&D on all major projects and technological development programs, the Decathlon Group has established a "decentralized" research activity (whose importance is variable depending on the case) at the level of "passion-brands" that have obtained a certain autonomy in this matter. Thus, Quechua or Tribord have acquired knowledge and skills allowing them to run the development of new goods by themselves, the first one in the field of water sports, the second one in the field of mountain sports. They have their own R&D engineers, designers, stylists, technicians. In the end, a sprawling and collaborative R&D has been built within the group. One can even speak of a "subsidiary" of the engineering with delegation of projects and programs. Each "passion-brand" has developed an expertise in its field with a strong sectoral expertise (snow skiing, fitness, running, riding...) that it may share, if necessary, with other R&D centres of the group. Ultimately, each brand has an engineering department to develop new goods concepts, whereas the Decathlon Research Center is in charge of basic research related to the human body. From now on, all the Decathlon Group innovations are the product of this original structure and some very promising ideas. Beyond its expertise in analysis of the movement and the athletes' body on one hand and in the design of sports goods on the other hand, the Decathlon R&D privileges a form of permanent and systematic creativity which leads to a great intellectual flexibility and a deep broadmindedness. With regard to Quechua, for example, there is somebody whose job is to develop innovation and run projects. This person has a certain ability to get used to changes, to breaks and to risk-taking. Through the creation of this job, the Decathlon Group gives itself the means to develop the winning combination of ideas production / opportunities for projects with high development potential. The organization of R&D, especially creativity, allows a permanent permeability to the outside world. "We regularly meet inventors and we are open to all proposals" says Irwin Wouts. Besides, it is not uncommon that proposals for new goods and ideas coming from outside have greater weight.

A dual management system of innovation and creativity

If the technical nature of goods directs part of the sports brands innovation process, non-technological determinants, especially organizational and human capacity to carry out an innovation project, also play a leading part. They would even be the core of the success model of the Decathlon Group and its "passion-brands" [START_REF] Richard | The Management of Sporting Innovation at Decathlon. Between Rationality and Chaos[END_REF]. According to the approach by resources and the concept of "core competencies" [START_REF] Hamel | La conquête du futur[END_REF], it is possible to reconstruct ex ante an innovation approach. In modelling the act of the company, we bring out specific organizational skills (Métais, 1997). The concept of resources or strategic assets derives from the desire to accurately describe the full potential of a company. It allows us to identify the basic entities which make up the innovative potential of a firm [START_REF] Dierickx | Asset Stock Accumulation and Sustainability of Competitive Management[END_REF][START_REF] Peteraf | The Cornerstones of Competitive Advantage: A Resource-Based View[END_REF][START_REF] Wernerfelt | A Resource-Based View of the Firm[END_REF]. The resources significantly involved in the success of innovations must necessarily be used to create some customer value [START_REF] Barney | Firm Resources and Sustained Competitive Advantage[END_REF][START_REF] Rindova | Constructing Competitive Advantage: The Role of Firm-Constituent Interactions[END_REF]. If they are tangible or inviolable assets belonging to the company [START_REF] Wernerfelt | A Resource-Based View of the Firm[END_REF], they are more or less complex to build -or to acquire -and it sets their power of differentiation [START_REF] Grant | The Resource-Based Theory of Competitive Advantage: Implications for Strategy Formulation[END_REF]. In these terms, the innovation skills of a company will then be defined as being the capacity to carry out a task or an activity thanks to the good use of the available resources. However, resources and capacities should not be confused. If a resource is an observable asset which can be evaluated and exchanged just like a brand, a plot of land, a licence or a patent, a capacity is not observable (thus necessarily intangible). It can neither be evaluated nor partly exchanged but only as a whole [START_REF] Makadoc | Towards a Synthetis of Resource-Based and Dynamic Capacity Views of Rent Creation[END_REF]. Competences of a company can be approached under the topic of distinctive competences [START_REF] Selznick | Leadership in Administration[END_REF], that is in taking into consideration fields where the company in question excels. Consequently, an implicit bond appears between the resources and the competences [START_REF] Hofer | Strategy formulation: analytical concepts[END_REF], insofar as thelatter are, ultimately, a convenient association of the whole entrepreneurial resources. In other words, the organisational capacity of a company would be determined by its aptitude for the deployment, the combination and the good coordination of its own resources, competences and knowledge (St-Amand & Fox, 2004). According to us, within the Decathlon Group, perfect alliance between the available resources and the existing competences build all the relevance of its management of innovation system. But, far from constituting a Cartesian and rigid model, this system takes, according to the different projects of development of the new goods, different original forms with sometimes fluctuating or surprising borders; however this does not a problem by virtue of the qualities of the management system! The commercially successful "passion-brands" goods are not exceptional. The exaltation of all the resources, competences and capacities of the group towards the concretization of top priority objectives -launching innovating goods that are, at any costs, commercial successes -will give a boost to each project. It should be said that the general direction of the group puts its staff under pressure: the R&D units are expected to concretize ten innovations or so per annum, not less! Ultimately, four guiding principles dictate the management innovation system implemented by the Decathlon Group (figure 2): creativity, design management, knowledge management and R&D. These four principles would seal the cohesion and the interdependence of all the productive and operational divisions of the group. It is a force of reduction and mutualisation which does not exist in the competitors' groups. Incorporating, for example, design-management in the middle of the growth device of a company is a step that few companies have taken. Wrongly, by the way, because it not only allows modification of the visions of the company and improvements to its strategy [START_REF] Cooper | Design as a Strategic Resource for Management[END_REF] and its competitiveness [START_REF] Trueman | Competing Through Design[END_REF], but above all, it allows the company better to assert its identity [START_REF] Dumas | Managing Design, Designing Management[END_REF]. Moreover, it favours a better coordination between the various functions of the company and it federates all the actors by making them work together on the creation projects [START_REF] Stokholm | Design Compass: Improving Interdisciplinary Communication in Design[END_REF] while improving overall innovation management [START_REF] Borja De Mozotta | Design and Competitive Edge: A Model for Design Management Excellence in European SMEs[END_REF]. Lastly, very often, the design seems to be the first factor of commercial success of the new goods [START_REF] Cooper | New Products: What Separate Winners From Loosers?[END_REF]. Associated with healthy competition between "inhouse" projects and strong values such as serendipidity 6 and intuition, the four guiding organize the Decathlon Group favourably in its potential aptitude "to revolutionize" the various segments 6. Serendipity (or fortuity) indicates the fact of finding, by chance or chance, something which one did not seek at the beginning.

of the sports markets where it is present. Compared with the innovations marketed for some time, this system of management seems, obviously, adapted to its policy of expansion and development.

Today, the really innovating companies are those which have abandoned technocratic rigidity and reconsidered their innovation management system by introducing freedom in it. It is them which, ultimately, created flexibility of thought and built a culture of innovation "on every floor" [START_REF] Ramecourt | L'innovation à tous les étages[END_REF]. Transformed by the resources, this flexibility will become a main organisational capacity to innovate. It will be obtained, in particular, by creating disorder. Indeed, in a more and more codified, standardized and rigid world, this disorder is privileged by a growing number of companies in want of innovations [START_REF] Alter | L'innovation ordinaire[END_REF]. But disorder implies that the company also takes risks (sometimes great risks), the consequences of which are not well known. Besides, it is for this reason that disorder is normally banished from organizations. Is not disorder disorganization? It also implies that the company is continuously on the verge of losing control of everything. It is a border which belongs to the implicit knowledge of the leaders and which is always very delicate to assess in a reasoned way. For the innovating company, the difficulty is to know exactly the limit between the acceptable and the unacceptable, to approach it to the nearest point: to seek a balance betweenorder and disorder. Whether in a stable or an unstable environment, the innovating company makes these two antagonistic forces coexist in its centre. The innovations would come mainly from the permanence of this status quo, and it seems that the Decathlon Group found it if we take into consideration the number of its new goods that have been commercially successful these last years. Let us quote for example the bicycle b'Twin, the skis Wedze or the swimming goggles X-base. While developing a competence, the Decathlon Group also developed an organisational capacity that is registered between the Cartesian rationality of a traditional management of innovating projects and the disorder characteristic of the creativity which falls under a kind of creative brainstorming. Concretely, if the company wishes to do it, it can adopt a "conventional" step when it has the necessary competences to conclude the development of a new good. Then, the innovation management system will be fully directed and framed, leaving little space to chance and uncertainty. On the other hand, if some projects move away from the competences and capacities available in-house, the management system of innovation can aim to this creative brainstorming, so as to favour the permeability to environment in order to better stimulate all the inventive forces of the individuals. The Decathlon Group finally ensures these project-teams a form of creativity and of directed freedom that, in the course of time, are developed and improved. In these project-teams, a kind of beneficial collective emulation creates itself as well as a strong tendency to make emerge new ideas with huge potential. Thus, on one side, there is a prevalence for a rational type management system and on the other, for a turbulent type management system. Finally, even if there is a possible risk of scatter, "turbulence" gives birth to exceptional ideas which a traditional management of innovating projects could never have made emerge. But we have to be careful. If, at Decathlon Group, the production of ideas can be carried out in a disorganized way, there is always a supervising authoritythe product manager is part of it -which will re-frame the project if it departs too much from the objectives set by the general direction. Two examples of recent innovations clarify the specificities of these two management systems at Decathlon Group (table 1).

Through these two examples of new products, we can say that the rationalinnovation and ideas management system is quite appropriate for the expert goods, those which are located on specialized markets and which are intended for the informed and demanding sportsmen. With the Tribord Inergy wetsuit, the project-team started from a scientific and very conventional R&D study on the elasticity of the skin to develop a wetsuit with the same properties. The study consisted in making tests with contact pads on a surfer's skin to know and model all its movements. Then, on the basis of acquired knowledge, the project-team sought to know which material would be the best for manufacture a wetsuit with high heating capacity and high elasticity (i.e identification of all types of neoprene in terms of stretch, tonicity, seam gluing, resistance…). In this project, the objective was to improve the surfer's tonicity while using the elasticity of the materials in order to amplify the surfer's movements, in particular when he must paddle with his arms to take speed. And in this project, it is the conjunction of several factors which led to an innovation allowing the development of a new type of wetsuit bringing more freedom of movement and better protection of the surfer from the cold. The Decathlon Group had the will to become a leader and to show a high level of technical skill in the field of neoprene wetsuits. Thus, in order to achieve this goal, it included talented sports advisers in the project-team and made thorough scientific studies in biomechanics, physiology and materials.

The turbulent innovation and ideas management system is more suited to general public goods which require less technical training and scientific knowledge. The implications on the central R&D unit on one side (the Decathlon Creation Center) and the relocated units on the other side ("passion-brands" R&D Centers) is not the same either (figure 3). With the Quechua's 2 seconds tent, the project-team rather "suffered" its project, because with no bill book and no precise idea of the solution to choose, it was dependent upon an external event. Regarding a concept much heavier and more complicated to develop (an igloo tent of the "umbrella" type), it is the fortuitous arrival of an inventor external to the company that stimulated theproject and found an original and very innovating solution to put it back on the rails. One can say that this person (providentially) dropped in at the right time and rather by chance! "He arrived just in time because we were less working on this problem and because we were doing some research inthis direction" says Irwin Wouts. However, it is because the project-team never focussed on a closed and unilateral research path that the opportunity (the arrival of new and exogenous ideas to the company) could be exploited judiciously and led to a category 4 innovation. The conjunction of three determining factors made this project a reality. Firstly, there was a somewhat similar project which had incubated since the middle of the 1990s. Secondly, a market diagnosis had revealed the two principal problems of thistype of product: a complex technical solution and a long assembly/disassembly time.

Thirdly, an inventor suggested an alternative project at the right time. The inventor's ideas have reactivated the original project which had difficulty to evolve/move because of a lack of in-house creativity. Compared to the two innovations presented previously, it seems that the R&D innovation process at Decathlon follows a "semi-chaotic/semi-organic" reasoning. At the beginning, nothing appears correctly structured, the ideas can fuse in all directions. On the other hand, once the green light of development is on, the company gives itself all the means to reach a satisfactory result, sometimes even exceeding all hopes (case of the 2 seconds tent). Today, this two-headed innovation and ideas management system applies to all the "passion-brands". Therefore, the innovation process gains in efficiency and allows the company to increase the launching of new goods. Today, an innovation project would be successful thanks to movement, adaptation, back-ups, hesitations, opportunities caught at the right time and especially a good support for new ideas (Thiétart, 2000). In the Decathlon Group, it is the dual organisation of the innovation process which proves its competency in the development of new goods compared with the competition within the sector. It is a distinctive competency (Hamel & Prahalad, 1996). The innovation management is built around a very moving dynamics centred on the free will of the members of the company [START_REF] Richard | The Management of Sporting Innovation at Decathlon. Between Rationality and Chaos[END_REF]. All is set up so that the innovation and the creativity are developed without hierarchical or technical restraint. However, building a strategy of innovation around a model of turbulent type is risky. Hence this possibility, for the Decathlon Group, to go back, if necessary, to a rational type management system, much more conventional and less favourable. But this innovation management, however effective it is, should not hide the fact that, within the Decathlon Group, as within any company, a certain organisational "counter-productive" lethargy might exist. It may come from a) the inertia of people who are always busy and not readily available, b) the inertia of ideas because people must convince themselves of the relevance of new ideas, c) the difficulty in giving money to develop ideas that, at the beginning, are not perceived as a source of profit for the company.

Conclusion : Towards a mangement of innovation with "variable geometry"

In their policy of innovation and growth, the Decathlon Group and their "passion-brands" gave themselves the freedom to choose between a stable and rational R&D activity that allows the minimization of risks, but often to the detriment of a research that may be long and costly (i.e. Inergy wetsuit), and an unstable and turbulent R&D activity which is potentially generating outstanding innovations having the capacity to modify an entire market segment (i.e. tent 2 seconds). In the first case, the chosen strategy, while acquiring a new know-how, rather seeks to strengthen a technical skill in a range of goods which requires investment in the field of technological and scientific research. In the second case, the chosen strategy is more like a prospective reasoning motivated by the desire to explore unknown horizons with the secret hope to succeed in finding outstanding innovations. Innovations that will become flagship or pervasive goods able not only to create new market niches, but also to launch new ranges of goods from the basic technical concept. Innovations resulting from the Decathlon Research Center R&D and the "passion-brands" R&D decentralized units follow different paths according to whether they are located in specialized niches (water boardsports for example) and intended for expert sportsmen (like bodyboarders and surfers) or located in non-specialized niches (like hiking and camping) intended for the general public (like vacationers and hikers). The creation of so different new goods is carried out according to distinct strategic models. Either it is through a rational type innovation management system rather in keeping with what is done in most of the innovating companies, or through a turbulent type innovation management system in which external competences and resources play a more or less important part directing the project towards very original solutions. The R&D of the Decathlon Research Center and the "passion-brands" R&D decentralized units authorize "variable geometry" flexibility of the group in the definition of the best ideas for new products. The organisational and strategic flexibility of this company appears atypical and distinctive today on the sports markets and even beyond! We consider that the Decathlon Group distinguishes itself from its principal competitors by a true strategic originality which will allow it rapidly to join the restricted circle of big world manufacturers of sports goods. It must be remembered that this company was created and has grown as a retailer. Today, it has got a portfolio of innovating brands which are not plain retailer brands any more, like those sold by competitors (i.e. Intersport in Europe, Go Sport in France, Authority Sport in the USA). Thus, we cannot say anymore that Decathlon is a distribution company. While developing in a vertical way within the sports industrial channel, it is from now on, a company that has diversified its activities and that is pursuing a double goal of 1) strengthening its position of European leader of the sports articles distribution (building of new stores), 2) becoming an industrial group, owner of renowned trademarks. On the other hand, after the invention of the first superstores specialized in sport, the Decathlon Group must now prove that its model of "passion-brands" is perennial and profitable.

Figure 3 :

 3 Figure 3: Coordination of R&D within the Decathlon Group according to the nature of the innovation projects

ii We make a point of thanking the people who evaluated the first version of this article and have improved it by their relevant remarks and suggestions. According to the customary formula, the remarks made involve us only as authors. 2. Since 2007, the Decathlon Group changed name. It became Oxylane Group. By convenience of language, in this paper, we will keep the original name which made all the success of the French company.

Beyond the R&D units, in order to encourage the emergence of the greatest number of ideas of innovations and new products, the Decathlon Group has created an annual contest, the Innovation Arward, for its 40.000 employees.


Gu Tingting

⋆ † Tang

Bao Xudong

‡ Dillenseger

GPU ACCELERATED HIGH INTENSITY ULTRASOUND ACOUSTICAL POWER COMPUTATION

Keywords: high intensity ultrasound therapy, simulation, interstitial therapy, GPU

The simulation of the hepatocellular carcinoma therapy effects is often used for the intervention planning. As the physical-based model of the simulation is very timeconsuming, the speed of this method becomes an obstacle during the clinical application simulation. In order to accelerate the simulation, a GPU-based (Graphic Processing Unit) acceleration method of the pressure field estimation is proposed in this paper. The results demonstrate that the proposed acceleration method can solve the time-consuming problem.

INTRODUCTION

High intensity ultrasound interstitial method is an alternative for the treatment of Hepatocellular carcinoma (HCC). This technique seems to be more advantageous for the control of depth and direction [START_REF] Lafon | Cylindrical thermal coagulation necrosis using an interstitial applicator with a plane ultrasonic transducer: in vitro and in vivo experiments versus computer simulations[END_REF]. During the clinical application, an efficient simulation of the effects of treatment should be made at the pre-operative stage. A first computer simulation tool for high energy ultrasound interstitial therapy assumed that the tissues are homogeneous with physical properties invariant during the treatment [START_REF] Lafon | Cylindrical thermal coagulation necrosis using an interstitial applicator with a plane ultrasonic transducer: in vitro and in vivo experiments versus computer simulations[END_REF]. But this assumption limited the accuracy and realism of the model. Garnier et al. introduced a more accurate model which takes into account the variation in time and temperature of the tissue attenuation coefficient [START_REF] Garnier | 3D modeling of the thermal coagulation necrosis induced by an interstitial ultrasonic transducer[END_REF]. This model is divided into several steps: 1) simulation of the pressure field generated by the transducer, 2) estimation of the temperature evolution over time and 3) estimation of the induced necrosis. In this framework, the pressure field simulation is one of the major points. The pressure field can be exactly estimated on the basis of Rayleigh integrals [START_REF] Lafon | Cylindrical thermal coagulation necrosis using an interstitial applicator with a plane ultrasonic transducer: in vitro and in vivo experiments versus computer simulations[END_REF]. As the computation of Rayleigh integral is very time-consuming, the speed of the implementation of the model becomes an obstacle for its use as pre-operative planning of the clinical application. In order to accelerate the estimation, Dillenseger et al. made several simplifications on the model [START_REF] Dillenseger | Acoustical power computation acceleration techniques for the planning of ultrasound therapy[END_REF]. However, the acceleration is still not satisfying and it brings high errors at the same time. To further accelerate the estimation of pressure field, we propose a GPU-based method. As the computation of each point in the pressure field is relatively independent and parallel, we think that it can be accelerated by the programmable graphics hardware due to its parallel computation ability. In this paper we will try to estimate the speedup efficiency and errors of this GPU-based method compared to the traditional methods computed on CPU.

METHOD

Ultrasound device

The modeled therapeutic ultrasound device is composed of a small planar ultrasonic monoelement transducer encapsulated in a cylindrical interstitial applicator (Fig. 1) [START_REF] Garnier | 3D modeling of the thermal coagulation necrosis induced by an interstitial ultrasonic transducer[END_REF]. The transducer is air-backed, so that the ultrasound is only propagated forward. The front face is cooled by water.

Pressure computation

The estimation of pressure field is a key point of the effect simulation. Numerical methods for estimating the pressure field can take into account the nonlinear propagation of high intensity waves or remain purely linear. Because of the relatively low power of the input transducer pressure and the non-focusing geometry of the probe, the propagation can be considered linear [START_REF] Duck | Nonlinear acoustics in diagnostic ultrasound[END_REF] and the pressure field can be exactly computed on the basis of the Rayleigh integral with O'Neil's hypotheses [START_REF] Lafon | Cylindrical thermal coagulation necrosis using an interstitial applicator with a plane ultrasonic transducer: in vitro and in vivo experiments versus computer simulations[END_REF]. The transducer surface S is sampled into elements of surface ∆S which size is negligible in comparison with wavelength λ

( ∆S < (λ/7) 2 )
. Each surface element can be considered as a single radial emitter. A location M and one element of surface ∆S are connected by a straight segment of length l sampled into elements ∆l as shown in Fig. 1. The pressure at M is given by the discrete version of the Rayleigh integral:

p(M ) = ∑ S j p 0 λ ∆S exp -jkl l exp -f ∑ l i=1 αi∆l (1)
with p 0 the pressure at the transducer surface (Pa), k the wave number (2π/λ), f the transducer frequency (Hz) and α i the tissue attenuation coefficient at location i along the line segment ∆SM (Np • m -1 • MHz -1 ).

Software simplifications

This two fold integration of (1) (over the surface of the transducer and along the segment ∆SM ) is very computation intensive, especially when the tissue attenuation coefficients α i are inhomogeneous over the volume and are temperature dependent [START_REF] Damianou | Dependence of ultrasonic attenuation and absorption in dog soft tissues on temperature and thermal dose[END_REF]. Dillenseger et al. [START_REF] Dillenseger | Acoustical power computation acceleration techniques for the planning of ultrasound therapy[END_REF] made several reasonable simplifications for the computation of Rayleigh integral. In the following part, we will briefly describe these methods. As α i can be taken into account in 4 different manners, the computation varies greatly in different conditions.

Adaptive sampling

As the pressure in the regions near the transducer presents larger variation than those more distant, adaptive sampling of the volume could be used to accelerate computation. An adaptive sampling of the points M over the volume is used. The pressure is first computed on one sample point every 8 sample points along each direction. The rule is: if the pressure values computed on adjacent sampled points is bellow than a first threshold P 1 = max(p(M ))/2 and if the difference between these two pressure values is lower than a second ad hoc set threshold P 2 = max(p(M ))/100, the pressure on the intermediate sample point is computed by linear interpolation, otherwise by Rayleigh integral (1).

Segments coherence

Adjacent ∆SM segments share almost the same attenuation properties. For a patch A of nine adjacent connected transducer surface element ∆S, the exp -f ∑ l i=1 αi∆l attenuation term of ( 1) is computed for only the ∆SM segment which originates from the central surface element of A and then applied to the 8 other segments which originate from A. Therefore, (1) can be rewritten as:

p(M ) = ∑ S ′ j p 0 λ ∆S ( ∑ A exp -jklp l p ) exp -f ∑ lc i=1 αi∆lc
(2) with S ′ the central surface elements of all patches A, l p the length from point M to each point of patch A and l c the length from point M to the center of patch A.

Mean attenuation

A much simpler method is to calculate the attenuation integration only one time. The attenuation is computed once along the ray from the center O of the transducer to the point M . On this condition, (1) can be rewritten as:

p(M ) = ( ∑ S j p 0 λ ∆S exp -jkl l ) exp -f ∑ lo i=1 αi∆lo (3)
with l o the length from point M to center of transducer O.

Constant attenuation

When the tissues are assumed to be homogeneous, the propagation of a wave from one element of surface ∆S to M is carried through 2 media: the cooling water of the transducer (α 1 ≈ 0, l 1 ) and the tissues (α 2 , l 2 ). Because of the transducer geometry, l 1 and l 2 can be estimated analytically and (1) can therefore be simplified to:

p(M ) = ∑ S j p 0 λ ∆S exp -jkl l exp -f α2l2 (4)
This assumption allows a relatively fast power field computation but to the detriment of realism.

IMPLEMENTATION ON GPU

Analyzing the Rayleigh integral, it is obvious that the bottleneck of the implementation of the algorithm is the large amount of parallel integral computation. The improvements brought by the different simplifications proposed in [START_REF] Dillenseger | Acoustical power computation acceleration techniques for the planning of ultrasound therapy[END_REF] are not satisfying considering the limited speedup as well as high errors.

In recent years, the rapid development of GPU and its unique parallel feature make it a new and brilliant tool for scientific computation. Parallelism could be performed on two level: 1) on a more lower level to estimate the pressure on one location M by the parallel pressure computation of each ray (from one element of surface ∆S to M ) and 2) on a more higher level by the parallel computation of the pressure at each M of the volume. Moreover, the exp -f

∑ l i=1 αi∆l
attenuation term is similar to the compositing equation used in volume rendering [START_REF] Levoy | Display of surfaces from volume data[END_REF], which inspires us to use GPU for acceleration. Therefore, we introduce GPU for accelerating Rayleigh integral.

We will only consider the computation of the pressure on one location M . In order to decompose the overall equation, the real part p r and imaginary part p i of the pressure induced by each ray are computed separately. Then the total pressure of ( 1) is achieved according to:

p(M ) = Q ( ∑ S p r ) 2 + ( ∑ S p i ) 2 (5)
where:

Q = p0 λ ∆S; p r = cos(-kl) l exp -f ∑ l i=1 αi∆l and p i = sin(-kl) l exp -f ∑ l i=1 αi∆l .
The program flow chart is shown in Fig. 2. First the sampled points of the transducer surface are transferred to the vertex processor of the programmable graphics hardware pipeline. After rasterization, the sampled points are sent into the fragment processor. Meanwhile, a 3D texture for storing the attenuation coefficients of the whole volume, the location of point M and other variables for computing p r and p i are transferred from CPU application into the fragment processor. Then, the fragment shader (program coded in GLSL -OpenGL Shading Language-for fragment processor) is executed in parallel by fragment processor to compute p r and p i . As GLSL is based on C and C++ syntax, the source program of the fragment shader can be designed similarly with that in C++ function except for transforming texture coordinates to Cartesian coordinates at first. At the end of fragment shader, p r and p i for each ray are stored respectively in two frame buffers, fetched by two 2D Textures and transferred into CPU application. Finally the overall pressure at point M is achieved according to (5) in CPU program. During the whole process above, only the computation of p r and p i is parallel and run on GPU. For the pressure computation of each sample point M , the process is also parallel. However, this parallel computation depends on parallel computation of each ray. This dependence makes it impossible to run on GPU.

RESULTS

Evaluation protocol

The comparison of the results obtained by the several simplification methods is performed with the following protocol. We simulate the pressure field p induced by a 5MHz transducer (Fig. 1) with an acoustical intensity of 40W/cm 2 . The size of transducer is 3mm × 9mm. It has been shown in [START_REF] Dillenseger | Acoustical power computation acceleration techniques for the planning of ultrasound therapy[END_REF] that a ∆S = (λ/4) 2 gives a good compromise between speedup and accuracy. The transducer is centered in a 80mm × 80mm × 24mm volume which is regularly sampled with a 0.4mm sampling step on 201 × 201 × 61 points.

The pressure field simulated by (1) (we will call it later brute-force simulation) only with CPU will be considered as reference. Several measurements are performed to compare the pressure field obtained by the several methods to the reference one or to compare GPU and CPU: the mean absolute error (labeled as mean abs. error), the mean relative error (mean rel. error), the computation time and the acceleration rate (acc. rate) which is the ratio of the computation time obtained by a simplified or a GPU-based method to the computation time of the reference method.

We have evaluated the whole implementation on a HP Z800 workstation equipped with a Intel Xeon 5504 2.00 GHz CPU, with 1.99 GB RAM and a NVIDIA Quadro FX 5600 (1536 MB) video card.

Results

The comparison of different methods is shown on Table 1. The four CPU simplification methods are corresponding to 1, we can see that among the four simplification methods, the fastest is the mean attenuation method. However, with the fastest computation speed, it brings big errors. The error of the second simplification method (labeled as seg. coh.) is the smallest, but its acceleration rate is not satisfying. From this table, we can clearly see that the performance of GPU-based method is the best. The speedup ability is considerable while the computation error is tiny. Compared to the results of the other simplification methods, this computation error even can be neglected. This GPU acceleration is even more significant when more rays are taken into account. For example, when the size of ∆S = (λ/10) 2 , the computation times of the two brute force methods are respectively 27507.5s and 60.3s (acc. rate = 456). The reason is that when the size of ∆S is smaller there are more parallel computation to be applied on GPU and therefore much more speedup brought by GPU.

GPU can also be used for implementing the acceleration methods as mentioned in Section 2.3. We tested the regular and adaptive volume sampling on all the methods. The comparison of these acceleration methods is shown on Table 2. The errors between a CPU-based and a GPU-based method is negligible. The acceleration rate between CPU and GPU computation differs between the several methods. We can see that the computation of the attenuation term takes the main benefits of the GPU computation. We draw a conclusion that to what extend an algorithm could be accelerated by GPU depends both on parallelism of the algorithm and computation cost of each parallel process.

CONCLUSION

In this paper we proposed a GPU-based acceleration method for the acoustical power computation during the planning of ultrasound therapy. The new method takes advantage of the parallel feature of the algorithm and the parallel computation power of GPU. The proposed method achieves considerable speed-up comparing to the traditional method while remain-

Fig. 1 .

 1 Fig. 1. Ultrasound device geometry and coordinates system.

Fig. 2 .

 2 Fig. 2. Program flow chart of GPU-based Rayleigh integral.

Table 1 .

 1 Comparison of different acceleration methods

	Methods	comp.	acc.	mean abs. mean rel.
		time (s)	rate	error	error %
	Brute Force CPU 4345.4	1.0	0.0	0.0
	adaptive	1098.7	4.0	2498.2	10.9
	CPU seg. coh.	286.9	15.1	76.2	1.0
	mean. att	107.5	40.4	202.5	1.6
	const. att	178.1	24.3	9991.4	28.5
	Brute Force GPU	22.1	196.6	2.4	0.059
	the methods introduced in Section 2.3. On GPU we retain the
	implementation without any simplifications.
	From Table

Table 2 .

 2 GPU on different acceleration methodsPressureSampling CPU time GPU time acc. rate The acceleration is much more considerable when the part computed on GPU (e.g. p r and p i in this program) is very time consuming. However, the parallel pressure computation at different space location M was not applied because its dependence on the parallel pressure computation of each ray. Further study could be focused on deliberately designing the program to make better use of the GPU parallel computation ability.

	method	method	(s)	(s)
	brute force	regul.	4345.4	22.1	196.6
		adapt.	1098.7	6.4	171.6
	segments	regul.	286.9	20.3	14.1
	coherence	adapt.	77.5	5.4	14.3
	mean att.	regul.	106.8	19.2	5.6
		adapt.	32.6	5.4	6.0
	const att.	regul.	178.1	16.4	10.9
		adapt.	47.1	4.7	10.0
	ing high computation accuracy.

This work is part of the French MULTIP project supported by an ANR Grant (ANR-09-TECS-011-06).


Robert-Vincent Joule

Fabien Girandola

Françoise Bernard

Fabien Girandolaand

How Can People Be Induced to Willingly Change Their Behavior? The Path from Persuasive Communication to Binding Communication

come

How can people be induced to willingly change their behavior? The path from persuasive communication to binding communication

cut meat). This goes to show the importance of the decision. According to Kurt Lewin, there exists no direct link between the ideas in our mind and our effective behavior. It is therefore necessary to call on an intermediary link and this link is none other that the decision action itself. Taken as a whole, Lewin's famous action research shows the advantage of securing a decision from the people whose behavior one seeks to change, given that once a decision is made, people tend to stick to it (freezing effect). Some decisions are easy to obtain. One just needs to ask -a simple request -for a decision to be made. But those easily obtained decisions can sometimes lead quite far. They can change a bystander into an actor, or a coward into a hero, as shown by a study carried out in the mid-1970s [START_REF] Moriarty | Crime, commitment, and the responsive bystander: Two field experiments[END_REF]. Stopping a thief The action takes place in a restaurant. Someone comes in carrying a briefcase and sits at a table, next to a person having dinner alone. A few minutes later, the man with the briefcase asks his neighbor for a light, thensteps out for a few minutes, leaving his briefcase unattended. A stranger enters the restaurant and tries to steal the briefcase. Only 12.5% of the people who had handed a light to the victim intervene to stop the thief. This percentage would be even lower if the bystander had had no prior contact with the victim. It wouldn't take much, however, for the bystander to react in a totally different way. Things would take another turn if the man with the briefcase had asked his neighbor for a different kind of small favor: for instance to keep an eye on his belongings. Indeed, in this situation, all bystanders, without exception, intervene to stop the thief. From a mere 12.5%, the percentage soars to 100%! People don't behave differently because they have different ideas. The patrons in the restaurant intervene -thus, carrying out the expected behavior (i.e. preventing theft) -because a stranger asked them to watchbetween one's ideas -namely, one's 'good ideas' -and one's actions.The Drug Abuse Resistance Education (DARE) program is another perfectexample of this gap. The DARE program, geared toward the preventionof drug use among teenagers, was set up in California and involved over9,000 students. Once again, although the program was effective in improvingthe students' overall knowledge of drugs and of their potential danger,its effectiveness in reducing drug use was poor (Dukes, Ullman, & Stein,1996;[START_REF] Ennett | How effective is drug abuseresistance education? A meta-analysis of project DARE outcome evaluations[END_REF].Of course, this does not mean that information and persuasion are useless.There is no question that, through time, information and persuasion serveto change knowledge, modify attitudes, and, most certainly, triggergenuine awareness. Information and persuasion are therefore necessary indeed, but not sufficient on their own (see, in particular, [START_REF] Albarracin | A testof major assumptions about behavior change: A comprehensive look at the effects of passiveand active HIVprevention interventions since the beginning of the epidemic[END_REF]Albarracin, Durantini, & Earl,2006).So how then can behavior be changed? Social psychologists have beentrying to answer this question for the past 60 years, and there is now awealth of reliable scientific knowledge on this topic. We have suggestedthat the research carried out in this particular domain could be brought back to a single basic paradigm: free will compliance (cf. Joule &Beauvois,1998[START_REF] Guéguen | Psychologie de la Manipulation et de la Soumission[END_REF]. From a practical point of view, this paradigm may be definedas the study of the procedures, or techniques, likely to lead others to modifytheir things. Social norms being what they are, bystanders can do nothing else but comply. Their values, convictions, attitudes, nature, or personality have no bearings here. It all depends on circumstances. Given other circumstances, they would behave differently, for example, if the stranger had asked for a light, all the more so, if the stranger hadn't spoken to them at all. The psychological process leading up to a change in behavior lies on a simple, easy to obtain decisionto keep an eye on the briefcase -and on the ensuing freezing effect. It goes without saying that some decisions are more difficult to secure than others and must, therefore, be prepared. There are several types of procedures enabling to prepare the ground for decisions likely to lead people to comply freely to what is expected of them. We have suggested to group these procedures in a single paradigm called 'free will compliance' ( Joule&Beauvois, 1998). In this article, we will discuss just a few of these procedures: low-ball, teasing, foot-in-the-door, touch, you are free to (see [START_REF] Cialdini | Influence: Science and Practice[END_REF]Guéguen, 2002a;[START_REF] Joule | Petit Traité de Manipulation à l'usage des Honnêtes Gens[END_REF]Girandola, 2003, for a summary).

Free Will Compliance

Low-ball procedure [START_REF] Cialdini | Low-ball procedure forproducing compliance: Commitment then cost[END_REF] were the first to describe the low-ball principle. A subject is led to make a decision, either by not being informed of its disadvantages or by being misled by false advantages. Once the decision is made, more details are provided, including information on the disadvantages of the decision or changes to the original positive deal. Subjects may then reiterate their decision or change their minds. The priming phenomenon translates into a tendency of subjects to strive to remain consistent with their first decisions although they needn't do so. Cialdini and his team carried out an experiment where students were invited to take part in a research. The participants, however, were not told that the research was planned to start at 7 a.m.! The students were informed of this early hour plan only once they had agreed to participate. The confederate then inquired to whether or not the students still agreed to take part in the research. The outcome is clear: compared to the control group that were given all the information up front, the low-ball procedure doubles the likelihood that students will not change their minds and that they will indeed show up at 7 o'clock in the morning (24% versus 53%, respectively). Both Moriarty's and Cialdini et al.'s researches show that individuals feel committed to a prior decision even when the conditions have changed. Decisions originally believed to be quite insignificant are maintained even when they suddenly turn out to be more costly than originally expected. The freezing effect as described by Lewin is not linked to the 'good reasons' that may have led participants to make a particular decision. If suchwere the case, people would reconsider their decision upon learning that their 'good reasons' are no longer applicable. But they tend not to reconsider precisely because the freezing effect is linked to the decision action per se rather than to the reasons for which a decision was made in the first place. The priming phenomenon provides a perfect illustration of this.

The teasing procedure

The teasing procedure [START_REF] Joule | The lure: A new compliance procedure[END_REF]) is quite similar to the low-ball procedure although its principle differs. People are encouraged to make a decision entailing positive consequences for them but that can only materialize ('teasing' request) after a less enticing decision is taken (substitution request). In an experiment carried out by [START_REF] Joule | The lure: A new compliance procedure[END_REF], students had agreed to participate in an interesting psychology research: they were to watch a really good movie and, on top of that, they would receive remuneration. The students were then informed that the research was cancelled and were invited to participate in a much less interesting -even boringnonremunerated research (repetitive paperand-pencil exercises). Twice as many students agreed to participate in this new study compared to the control condition where no 'teasing' requestwas made. Teasing has certain similarities with priming yet differs in one major way: in priming, both decisions are linked to the same object (for instance in Cialdini et al.'s experiment, i.e. to participate in a given study) while in teasing the first and second decision concern two different objects (for example, in Joule et al.'s experiment, i.e. to be paid to watch a good movie or to write repetitive exercises in a new nonremuneratedresearch). Teasing leads us to the foot-in-the-door procedure that also involves two decisions geared toward two different objects.

The foot-in-the-door procedure

The foot-in-the-door technique, first coined by [START_REF] Freedman | Compliance without pressure: The foot-in-the-door technique[END_REF], is unquestionably the oldest free will compliance procedure and one that has generated the most research (for a review, see, in particular, [START_REF] Burger | The foot-in-the-door compliance procedure: A multiple-process analysisand review[END_REF]. It should be mentioned that this procedure can be observed on a daily basis. Its principle is well known: a small request (preparatory action) is made prior to a more substantial one (expected behavior). In one of their most famous experiments, Freedman and Fraser began by asking housewives to answer a few innocuous questions over the phone about their consumption patterns (preparatory action). A few days later, the housewives received a phone request aimed at triggering the expected behavior. They were asked to agree to a 2-hour interview concerning household consumption. The interview was to be carried out in their home by a team of several men. Freedman and Fraser observed that such a costly request was twice as likely to be complied to when it waspreceded by a smaller request than in the control group where the housewives had not been contacted beforehand for a quick phone survey (52% versus 22.2%, respectively).

In this foot-in-the-door experiment, an explicit request is aimed attriggering the expected behavior: 'Would you allow our team of surveyorsto interview you at home?' Such is not the case in other research, wherethe conditions likely to incite the person to spontaneously behave asexpected are set up without putting forth an explicit request. Insofar asthe expected behavior is not the object of a request per se, some researchersrefer to foot-in-the-door with implicit request.

Foot-in-the-door with implicit request

In a series of studies carried out in Aix-en-Provence, France [START_REF] Joule | Qui dit quoi, à qui, en lui faisant faire quoi? Versune communication engageante[END_REF], we were able to show just how easy it is, using the footin-the-door with implicit request technique, to make someone behave ina more honest way than he or she spontaneously would in normal circumstances.One such experiment took place in a deserted alley where apasserby was seen dropping a 10-dollar bill. A mere 20% of the eyewitnessescaught the passerby's attention while the other 80% let him moveon and grabbed the money!Yet, a carefully designed preparatory action could increase the likelihoodthat eyewitnesses would behave in a more honest way. The likelihood ofhonest behavior is multiplied by two (40%) in situations where thebystanders are first led to do a small favor -for instance, give directions-to another passerby. And it is even higher (70%) when the favor isslightly more costly, that is, to walk a distance of about 30 meters to helpsomeone find their way. Once again, if some people tend not to takemoney that doesn't belong to them, it has nothing to do with theirpersonality, values, or moral standards, but rather because they wereencouraged to carry out a preparatory action, that is, to do someone asmall favor. It thus seems that this first favor enables the person to makea connection between what she or he has done (namely, giving someonedirections or walking a few steps to help someone find their way) andwho he or she is (someone willing to help). And wouldn't such anobliging person tell a passerby that he or she has dropped money?

Foot-in-the-door with labeling

In another series of studies carried out in Aix-en-Provence (quoted by Joule&Beauvois, 2002, 178-180), we were able to show that the foot-in-thedoorprocedure could be even more efficient if the labeling techniquewas also used. One research took place on market day. A first confederatepretended to be a tourist and asked a shopper to help him read a city map(preparatory action). Once the favor had been secured and just beforeleaving the tourist confederate proceeded to label the shopper: 'I was so fortunate to come across someone as nice as you.' Later on, a secondconfederate in the crowd handed the shopper a banknote: 'Here, I thinkyou've lost this.' By doing so, the likelihood that an 'aixois' will turn downmoney that is not his or hers is eight times higher (64%) than in the controlcondition (only 8%) with only one confederate. This effect turned out tobe twice as high compared to a foot-in-the-door situation without labeling(30%), where a first confederate warmly thanked the shopper for havinghelped him find his way on the map. The foot-inthe-door technique cantherefore be optimized by using the appropriate labeling, that is, one thatunderscores the personality trait corresponding to the expected behavior.

The touch procedure

The touch procedure was first identified in the 1970s and consists intouching a person's arm for 1 or 2 seconds to secure his or her compliance.In one of the first studies [START_REF] Kleinke | Compliance to requests made by gazing and touching in field settings[END_REF], a few coins were left ina phone booth. People leaving the phone booth were asked if they hadfound money in the booth. One time out of two, the confederate wouldnot just enquire about the coins but would also touch the person's armthus substantially improving the rate of return of the forgotten coinstwofold. The effectiveness of this procedure is well established. The effectof touch has been observed in different contexts and for various types ofbehavior. The University of Miami hosts the Touch Research Institute. Inthe medical field, hundreds of studies have been conducted proving thepositive effect of touch in securing compliance to a desired behavior.For example, patients touched by hospital staff were more likely to followmedical prescriptions, hospital patients experience less presurgery stresswhen a nurse has touched them, and finally patients are more likely to go back to a psychiatrist if he or she touched them during the first session.First observed in the USAtypically a 'noncontact culture', the phenomenonremains effective in a 'contact culture' such as France. [START_REF] Guéguen | King of touch, gender and compliance to a request: A pilot study[END_REF] observed, for instance, that a person is twice as likely to give acoin to a stranger if he or she has touched his or her arm during therequest. In another study, [START_REF] Guéguen | Nonverbal encouragement of participation in a course: The effect oftouch[END_REF] observed that touching astudent's forearm during a corrective exercise multiplied by almost threethe likelihood that the student will volunteer to go to the board todemonstrate the exercise. This last research is in line with Americanresearch showing that a teacher can help students improve their schoolperformance by merely touching them [START_REF] Steward | Touching as teaching: The effect of touch on students'perceptions and performance[END_REF].

The 'you are free to' procedure It was recently shown that explicitly calling on a person's feeling of freewill increases the likelihood that this person will behave according to one'sexpectations. The principle of this procedure is to end a request by specifying that the person is totally free to do (or not) what is requestedof him or her. This technique has enabled [START_REF] Guéguen | Evocation of freedom and compliance: The 'but you arefree of[END_REF]to multiply by four their chance of having people giving them money inthe street. They asked a stranger for money to take the bus, adding 'but you are free to accept or refuse' (10% versus 47% with the 'you are freeto' procedure). Other studies [START_REF] Guéguen | Request solicitation and semantic evocation of freedom: An evaluation in a computer-mediated communication context[END_REF] have shown that the fact of replacing the traditional 'clickhere' with 'you are free to click here' increases the number of hits on aWeb site. The free will compliance procedures previously mentioned (priming,teasing, foot-in-the-door, touch, you are free to ... ) prove that it is in factquite easy to influence the behavior of others and to increase the likelihoodthat people will freely comply to what is expected of them. Theadvantage of these techniques is that they are more effective than othermore authoritarian procedures that are likely to be ineffective or inappropriate.Of course, it is out of the question that housewives be forced toagree to having a team of surveyors spend 2 hour in their homes. Likewise,we are not aiming at compelling a passerby to give us money to takethe bus. When we choose to talk about complianceinsofar as peoplewould have spontaneously behaved differently -we are actually referringto a different type of compliance, that is, free will compliance.

The Theory of Commitment

In our opinion, the theory of commitment provides the best theoreticalinterpretation of free will compliance phenomena [START_REF] Girandola | Action and commitmenttheory[END_REF]Joule&Beauvois, 1998;[START_REF] Kiesler | The Psychology of Commitment. Experiments Liking Behavior to Belief[END_REF].According to Kiesler, people who act become committed, almost despitethemselves, to their action hence impacting people's attitudes and behavior.As far as attitudes are concerned, committing oneself to a counterattitudinalaction (i.e. one that goes against one's attitudes) results in achange of attitude or rationalization (a better adjustment of attitude toaction). Whereas commitment to an action in line with one's attitudesleads to a consolidation of the attitude. A better resistance to subsequentinfluence attempts may be observed in that case. For example, signing apetition in favor of a cause that one holds close to heart enables to betterresist attacks targeting this cause.Concerning behavior, committing oneself to a decisional action leadsthe person making this decision to stick to it (freezing effect, low-balleffect). Committing first to an innocuous action increases the likelihood of complying to subsequent more demanding requests as long as thecourse of action remains consistent (teasing effect and foot-in-the-door).However, this type of impact on attitudes and behavior can be observedonly as long as the first action (preparatory action) was carried out inspecific commitment conditions. Therefore, the same action can be more or less binding, and can even be seen as nonbinding. Studies have shownthat the stronger the commitment the bigger the effects.Strong commitment can be obtained by playing on several factors,among which:

1 The context of freedom in which the action was carried out: an actioncarried out in a context of freedom is more binding than when carriedout in a context of constraint.

2 The public nature of the action: an action carried out in public is morebinding than when anonymity is guaranteed. 3 The explicit nature of the action: an explicit action is more bindingthan an ambiguous one.

4 The irrevocability of the action: an irrevocable action is more bindingthan one that is not.

5 The repetition of the action: an action that is repeated is more binding than an action carried out once.

6 The consequences of the action: an action will be more binding if it isfilled with consequences.

7 The cost of the action: an action will be more binding if it is costly inmoney, time, energy, etc.

8 The reasons for the action: an action is the more so binding that it cannotbe attributed to external reasons (e.g. promises of a reward, threats ofpunishment) but can be imputed to internal reasons (e.g. personalvalues, personality traits). In other words, external reasons unbind whileinternal reasons bind.

According to the circumstances, subjects will feel more or less bound bythe act they were induced into doing. We can therefore understand whyKiesler chose to define commitment as the link between people and theiractions. It is quite easy to grasp, for instance, that the link will be strongerwhen the person acts in a context of freedom rather than in one ofconstraint. But one should be careful: it is not the subjects per se whocommit to their actions according to their ideas. In such a case, we wouldindeed be authorized to talk about 'internal' commitment. We are referringhere to 'external' commitment because the fact of committing oneself(or not) to one's actions derives from circumstances with their objectivecharacteristics. Kiesler's definition is somewhat ambiguous on this mainpoint. We would therefore prefer to use the following definitions that betterunderscore the external -and solely external -nature of a commitment:'In a given situation, a commitment corresponds to the conditions inwhich an action can only be attributed to the person who carried it out,'or 'a commitment corresponds to the conditions in which an action wascarried out and enabling an attributor (either an eyewitness, the personhim or herself, or any person aware of what happened) to match thisaction to the person who carried it out' ( Joule &Beauvois, 1998, 60).

The Path to Binding Communication

Throughout this article, we have shown that good ideas are not enoughto make people change their ways. But we have also shown that it doesn'ttake much -namely, a few well-designed preparatory actions -to inducepeople into moving from ideas to actions. For this reason, we deem thatcommunication campaigns could be more effective if the preparatoryactions to be obtained by the target were not neglected. This is quite achallenge as it entails imparting to the target a status of player rather thanmerely receiver. From a practical point of view, the target's player statuswill lead him or her to carry out binding preparatory actions 'inconsistent'with the subsequent influences that we want him or her to resist (incitementto drug use or racial hatred, for example). To the contrary, thepreparatory actions will actually lead the target to carry out actions consistentwith the subsequent desirable influences (educational or awarenessmessages, for example).In any given program of communication, the main questions to betreated remain of course: 'What type of information should be conveyed?''What are the best arguments to offer?' 'What are the most appropriatechannels, tools, supports, and medias?' etc., but more importantly, 'Whichpreparatory actions must I obtain from those I want to rally?' This lastquestion imparts a status of player to the target, thus, setting apart a 'binding'communication approach from a more 'traditional' approach (see, inparticular, [START_REF] Joule | Qui dit quoi, à qui, en lui faisant faire quoi? Versune communication engageante[END_REF].To illustrate this point, we will describe a 'binding' communicationaction carried out in 11 schools in the south of France within the frameworkof the European project ALTENER. The aim of this project, whichtook place during the 2002-2003 school year, was to encourage 9-and10-year-old children and their parents to develop environmentally friendlybehavior. Seven hundred families along with 28 teachers were involved.During the school year, the teachers did more than just inform (lessons,background information, etc.) and convince students of the importanceof protecting the environment and of conserving energy, they made theirstudents actually carry out preparatory actions (about once a month). Thefirst action was to determine what were the environmentally friendly andenergy saving 'good practices' and the 'notso-good practices' in theirschool. In a second action, the children were asked to do the same thingat home by taking note of family habits that could be changed withoutcausing much inconvenience. The third action involved parents (firstpreparatory action for the parents) who were asked to help their child fillin a questionnaire about energy savings at home. In the fourth preparatoryaction (second for the parents), the child put a sticker about the preservationof the environment on the family fridge, etc. Obviously, the results of each preparatory action were shared withothers in school. The children talked about what they had noticed atschool and shared their findings about their own homes. The children read and analyzed together the questionnaires filled in with their families. Each child spoke about family reactions to the sticker on the fridge.At the end of the school year, each student was encouraged by theteacher to make a public and written commitment to change at least oneof his or her habits, for example, to take a shower instead of a bath or toturn off the tap when brushing their teeth. Each child was to inform hisor her parents of this commitment also encouraging them to make aspecific commitment of their own: to leave the car at home when travelingshort distances or to replace ordinary bulbs by low wattage bulbs. Thesecommitments were made more official through the signing of two forms:the child signed one in the classroom, and the family signed one at home.The conclusions are very positive. The vast majority of children and parents (100% in some classes), made a written pledge to carry out specificactions likely to decrease energy consumption. Several studies have shownthat written commitments are more likely to be followed through (see, inparticular, for environmental issues: Katzev& [START_REF] Katzev | Can commitment change behavior? A case study of environmentalactions[END_REF][START_REF] Pallack | Commitment and energy conservation[END_REF][START_REF] Wang | Group commitment and resource conservation: two fieldexperiments on promoting recycling[END_REF], for a summary of the long-term effects of commitment, see Girandola&Roussiau, 2003). It's hard to imaginehow parents, who, at the request of their son or daughter, have made awritten commitment to replace ordinary bulbs by low wattage bulbs could not do it. Parents generally want to set a good example and do not want their child to perceive them as untrustworthy. But there is more. Thedynamic set in motion by this approach has also led to improvements insome of the schools such as switching from ordinary bulbs to low wattagebulbs or setting up paper recycling bins. Finally, some students wrote tothe local authorities to ask that timers be installed for the lights in schoolcorridors.The above action represents a perfect example of a binding communicationapproach. It is not just about presenting targets with informationand arguments. Efforts are put into encouraging targets (i) to carry outpreparatory actions and (ii) to make specific commitments. In promotingthis approach, our aim is to support the development of studies seekingto integrate, on the one hand, research on the role of commitment andfree will compliance with, and on the other hand, research dealing withcommunication in general and those with a more specific focus on persuasivecommunication. This direction seems quite promising as it offersexciting new paths for research having important theoretical and practicalimplications.

Short Biography

Robert-Vincent Joule is Professor of Social Psychology at Université deProvence (France). He is Head of the Laboratoire de PsychologieSociale.His research interests are in cognitive dissonance and social influenceprocedures (free will compliance). He is the author (with Jean-Léon Beauvois) of A Radical Dissonance Theory (London and Bristol: Taylor &Francis, 1996). His most recent research concerns communication andmore specifically 'binding communication'. His best-known works are Lasoumissionlibrementconsentie(Paris: Presses Universitaires de France, 1998) (written with Beauvois) and also the Petit traité de manipulation à l'usage deshonnêtes gens (Grenoble: Presses Universitaires de Grenoble, 2002), a best seller that has sold 200,000 copies in France and has been translated inseveral languages (also written with Beauvois). He was awarded the Prix de la diffusion scientifique at the Festival des Sciences et des Technologies en 2002 (President of the Jury: Yves Coppens).

Fabien GirandolaisProfessor of Social Psychologyat Université deBourgogne (Dijon, France) and assistant director of the Laboratoire deSocio-Psychologie et Management du Sport. His research focuses on the theory of commitment, cognitive dissonance, social influence procedures(free will compliance), persuasion and resistance to persuasion, decisionmaking.His most recent research interest is on 'binding communication'more specifically in the domain of environment, health. He is the author of Psychologie de la persuasion et

Endnote

* Correspondenceaddress: Laboratoire de Psychologie Sociale, Université de Provence, 29 avenueR. Schuman, 13621 Aix-en-Provence Cedex 1, France. Email: joule-rv@up.univ-aix.fr.

  de l'engagement (Presses Universitaires deFranche-Comté, 2003).Françoise Bernard isProfessor of Information Sciences and Communicationat Université de Provence (France). Sheis Head of the Centre deRecherche sur les Pratiques de Communication et de Médiation. ShewasPresident of the Société Française des Sciences de l'Information et de laCommunication from 2002 to 2006, and iscurrentlyitsHonoraryChair. She has worked on communication, change, and innovation within organizations. Her most recent research focuses on 'binding communication' and is conducted in partnership with Robert-Vincent Joule. She examines, among other things, the relationship between communicationand action in the domain of the environment.