François Daniellou

est destinée au dépôt

From the orkers' a ti ity to the ergo o ists' a tio

François Daniellou

The fiftieth anniversary of the SELF foundation, and this plenary session, are an opportunity to bring up questions about SELF's specific contribution to the development of Ergonomics in the world, tryi g o e ore to esta lish hi h light a ti ity oriented ergo o i s sheds o international debates about our discipline and profession. The reading of the position paper A strategy for hu a factors/ergo o ics: developi g the discipli e a d professio , by Jan Dul and other outstanding contributors, was the starting point for this reflection exercise. Due to the limited time of this presentation, it will focus only on work system ergonomics, which addresses the production of goods or services. Mass product design might require different developments.

An activity oriented ergonomist feels comfortable with many of the assertions presented in the paper, notably the facts that Ergonomics has a system approach and is design driven. But he/she completes the reading of the paper with a strange feeling, partially expressed by Nathanael and Marmaras's o e tary: fitting a system to the human appears to be rather simple for good experts of high-quality HFE, as long as they have at their disposal updated knowledge and methods. Their main problem seems to be the marketing of their talents. We must admit, on the other hand, that our everyday life is one of struggles, contradictions and conflicts, negotiations, successes and failures.

To understand this discrepancy, let us have a look together at any workplace, with our differe t pairs of glasses. Ma y HFE spe ialists ill assess this orkpla e, usi g scientific criteria to evaluate which components of the system are adequately, or poorly, fitting hu a apa ities a d aspiratio s , resulting in lower or higher levels of well-being and performance . An activity oriented ergonomist will try to understand how the worker struggles to do his/her work well, in the midst of a number of constraints and contradictions, and which consequences this activity may have on performance and health.

Indeed designers and organizers have set up the work means, by using general, technological knowledge about the products and processes. But, in spite of the attention paid to this anticipation, what will happen in real time always differs from what has been planned: the material drifts from its reference state, the tools wear out, incidents occur, clients have unexpected demands, etc. Even in highly taylorist surroundings, variability is the rule. If the worker merely did what he/she is prescribed to do, little production would come out. When they do that, it is called a work-to-rule strike, and production is blockaded.

Any worker has to compensate for the limitations of the design anticipations: the gap may be wide in the case of poor design, it may be smaller in that of better design. But it is always present. To take care of the situation as it is, the worker mobilizes his/her body, his/her intelligence and experience, his/her networks, but also his/her subjectivity and values to stri e to do ell do e ork . He/she puts i to play a adaptati e a ti ity to try to balance the production goals, the expectations of clients or colleagues, the actual state of the system and of means available for work, the capacities, limitations and variations of his/her body, and the compliance with his/her values. He/she continuously builds trade-offs between those contradictory drives; in difficult situations, the inevitable imperfection of those compromises may result in performance and/or health problematic outcomes. Activity analysis is an attempt to understand the determinants of this adaptative activity, its favourable outcomes, its frustrations, as well as its costs in terms of both performance and health.

If you accept to follow us on this line of approach for a few more minutes, let us try to draw some of its consequences as regards models of the human, and targets of ergonomic interventions.

HFE models of the human started with physiological references, that have permitted to understand detrimental effects of many efforts, postures, environmental conditions or perceptual activities. Then, they began to include cognitive dimensions, not only in intellectual professions, but also in so-alled a ual ork . Information processing, representation building, cognitive interactions, decision making, cognitive strategies have become common references for many HFE specialists.

The explosion, not only of psychosocial risks but also of musculoskeletal disorders imposes us a new inescapable challenge: we have to endow our models of the human with credible and operating descriptions of the mobilization of subjectivity at work. The paper mentioned a o e refers to hu a aspiratio s . U fortu ately, well-being is not a state, whose boundaries can be easily defined and assessed. The human incessantly struggles with the urges of life desires and their framing by social norms. His/her health hinges on his/her capacity to build, in interactions with others, his/her own route, in which being oneself results reasonably acceptable for the society.

It is now clear that work is one of the major arenas of this confrontation between the individual's o or s, a d so iety's norms. This means that favourable work situations are those in which the worker happens to influence the environment, in order to yield outcomes in which he/she can recognize something of him/herself. If so, the person develops his/her competence, and work is likely to have a positive contribution to his/her health. But if, which turns to be more and more common, the type of quality required by the organization, or the ea s a aila le to rea h it, are a tago isti to the orkers' oti atio s a d alues, he/she may persist for some time in struggling in the shadow, alone or with the work group, to do his/her work well, in spite of, or against, the organization. If these desperate attempts finally fail, his/her health is put at risk, and psychosocial risks or musculoskeletal disorders are highly presumable consequences.

What is at stake ultimately in the workplace are the conditions of the confrontation between two types of knowledge: the scientific and technological knowledge thanks to which the workplace has been designed and organized by anticipation, on the one hand; the experience and embodied knowledge of those who hold the work position and who, day after day, mobilize themselves to take care of what has not been anticipated by the organization, on the other hand. Oftentimes, this confrontation is defective in at least, two key stages: at the design stage, and in everyday production organization. In many organizations, decisio akers' k o ledge has few opportunities to o e a ross orkers' knowledge.

The ergo o ists' task is, indeed, to introduce knowledge about the human at work in the design or the redesign of work systems. But it is not only that: we have to foster the confrontation of different knowledge, different standpoints, different logics in the design or redesign process. Holding together performance and health in HFE interventions is not a smooth optimization process. It cannot make do with ergonomic recommendations. It is the introduction, in the organization, of new actors, new descriptions, new models, new debates, new design objects, new methods, new criteria, structured around one central question: what is the room for manoeuvre that is required and possible in the future system, so as to enable the workers to do their work wellwhatever the variability of the context -, at an acceptable individual and collective human cost, to develop their competence and to contribute to an on-going development of the system itself ? Thus described, the ergonomic intervention has little to do with the mere application of scientific knowledge about human properties. The ergonomists need methods to analyse the determinants of the contradictions which activity has to cope with in a given workplace; to build o e's right pla e a o g desig ers, de isio akers a d other stakeholders; to organize simulations of possible activity and its consequences for performance and health in a future system; to promote the confrontation of various stakes and the building of unexpected trade-offs.

Of course, knowledge can, and indeed should, be produced about these action processes and the relevant methods to steer them. But this knowledge may not be developed in the lab: it requires a systematic approach to building models of ergonomic interventionsaddressing different contexts -, the publication and teaching of these models, their public critique among the profession, and their continuous iterative improvement. We are raising here a major epistemological question: not only is knowledge the source of HFE action; action, and its modelling, is a key source of HFE knowledge.

So, now, what about the marketing of HFE interventions? As a matter of fact, the processes

e ha e just ee des ri i g are early u arketa le as su h! I ost ases, you just a 't advertise on the importance of new actors playing a role, on the virtue of contradictions and debates. Still, we share with the above mentioned paper the idea that there are so many preoccupations that ergonomics may address, affording such as diverse gateways as occupational health, production and quality stakes, major risks, prevention of exclusions, return to work, age management, etc. We could add to this list the specific own difficulties of shopfloor or middle managers.

The clients or possible clients of HFE specialists do not need HFE: they need help; tailored help! It is the dis ipli e a d professio 's duty to develop methods and knowledge that foster the capacity of professionals to be present in the right place at the right time, to perceive these preoccupations of a number of stakeholders, to negotiate and to build interventions adapted to each context, to accompany the stakeholders all the long way from the expression of their concerns to the redesign of the system; to draw lessons from successes and failures, and to circulate and discuss in the community capitalized feed-back on intervention methods.

As a conclusion, let us sum up some possible contributions of this SELF congress to the IEA debates:

1) The object of ergonomics is to promote favourable conditions for the development of purposeful human activity, through an action on the design of systems; 2) Workplacesin their technical and organizational dimensionsshould not only be innocuous, they should foster the development of the individual, the work groups, and the system itself: we aim to contribute to the design of enabling environments and learning organizations, which requires assuming contradictions and promoting debates; 3) An ergonomic intervention is not a mere added contribution to existing decision making processes in design or organizing: it changes the decision making processes themselves, the actors involved, the topics that are tackled, the criteria that are used; 4) Knowledge has to be produced about these action processes, through iterative modelling and assessing of field interventions: this requires forms of collaboration between academics and practitioners that be significantly different from the knowledge supplier / knowledge user model. A continuous improvement loop, involving structured interactions between researchers and practitioners, is necessary to test and to develop these models; 5) Perfor a e , health or ork orga izatio are not obvious, univocal concepts.

The IEA has a specific role in 1) promoting internal debates about them and 2) interacting with such disciplines as management science, economics, sociology, anthropology, psychology and psychopathology, to promote a vision of human development at work as an inescapable condition of sustainable performance; 6) HFE, and the IEA, have a vital interest in tackling such epistemological questions, and in analysingand if necessary combatingthe limitations that the positivist approaches to science production and scientific publication impose to the production of knowledge about action.


Jesus Gonzalez-Feliu
email: jesus.gonzales-feliu@let.ish-lyon.cnrs.fr.

Josep-Maria Salanova-Grau

How the location of urban consolidation and logistics facility has an impact on the delivery costs? An accessibility analysis

Keywords: urban consolidation, simulation, scenario assessment, distance-based accessibility

Urban consolidation is a popular subject in city logistics. Moreover, public authorities need adapted decision support methods to analyse the interaction between their land-use choices and the transformations in trip behaviour, for both personal and commercial trips. This paper proposes a simulation method to carry out a landuse and transport interaction analysis based on the notion of accessibility, and applies it to the real urban network of Lyon. First, a literature review on accessibility and simulation of goods flows is made. Second, the proposed method is presented on the form of a sequential procedure. First, a demand generation model estimated the weekly number of demands to deliver to each customer, to what we convert the generated number of deliveries into a daily number of freight transport demands including a quantity of goods to deliver and a customer, via an empirical procedure. Then, a spatial analysis to choose the most suitable sets of potential logistics facilities is proposed. Finally, each platform is associated to a distance-based accessibility indicator. Computational results are presented and discussed. Finally, recommendations to public authorities for their land-use policy assessment in terms of impacts on freight transport are proposed.

Résumé

La consolidation urbaine est un sujet populaire en logistique urbaine. En outre, les pouvoirs publics ont besoin de méthodes d'aide à la décision adaptés pour analyser l'interaction entre leurs choix d'utilisation de l'espace et les mutations et impacts des comportements de déplacement, tant pour les personnes comme pour les marchandises. Cet article propose une méthode de simulation pour analyser l'interaction transport territoire basée sur la notion d'accessibilité, appliquée au cas réel de l'aire urbaine de Lyon. Tout d'abord, une revue de la littérature sur l'accessibilité et la simulation du transport de marchandises en ville est proposée. Ensuite, la méthode envisagée est présentée sur la forme d'une procédure séquentielle. Premièrement, la méthode utilise un modèle de génération de la demande de transport de marchandises, puis une méthode empirique pour obtenir la quantité journalière de marchandises à livrer. Ensuite, une analyse spatiale pour choisir les centres de distribution urbaine les plus appropriés est proposé. Enfin, chaque plate-forme est associée à un indicateur d'accessibilité basé sur la distance parcourue. Enfin, des recommandations pour les acteurs publics dans leur évaluation des politiques d'utilisation de l'espace urbain en termes d'impacts sur le transport de marchandises sont proposées.

Mots-clé: centres de distribution urbaine ; analyse de scénarios ; accéssibilité type distance.

Introduction

Urban consolidation is a popular subject in city logistics as shown in recent works [START_REF] Allen | The role of urban consolidation centres in sustainable freight transport[END_REF][START_REF] Morana | Urban Consolidation and Logistics Pooling[END_REF]. However, the classic concepts of urban consolidation centres (UCCs) with a public service vision present several limits and need to be revised [START_REF] Ville | The limits of public policy intervention in urban logistics: Lessons from Vicenza (Italy)[END_REF]. Moreover, the complex context and the wide variety of alternatives to classical UCCs justify the need of assisting public authorities to be supported by decision aids methods to analyse the interaction between their land-use choices and the transformations in trip behaviour, for both personal and commercial trips. More precisely, the last trends in urban consolidation (micro-consolidation, single-carrier schemes and collaborative systems) need to be assessed and estimated in a coherent way. One of the main questions that arise is that of better choosing the consolidation points to deliver an urban zone, mainly in case of collaborative schemes.

This paper proposes a simulation method to carry out a land-use and transport interaction analysis based on the notion of accessibility, and applies it to the real urban network of Lyon. First, a literature review on accessibility and simulation of goods flows is made. Second, the proposed method is presented on the form of a sequential procedure. First, a delivery-based demand generation model estimated the weekly number of demands to deliver to each customer, to what we convert the generated number of deliveries into a daily number of freight transport demands including a quantity of goods to deliver and a customer, via an empirical procedure. Then, a spatial analysis to choose the most suitable sets of potential logistics facilities is proposed. To each facility, a number of vehicles is assigned, using a statistical method derived from French National Surveys of urban Goods Movement. Finally, each platform is associated to three accessibility indicators: a cost-type, a gravity-type and an utility-type. After that, routes are estimated using a semi-greedy algorithm for the consolidation 2E-VRP (Two-echelon vehicle routing problem, see [START_REF] Gonzalez-Feliu | Freight distribution systems with cross-docking: a multidisciplinary analysis[END_REF]. Since instances are of real size and the number of tests of the accessibility is elevated (about 100 tests with more than 400 customers and non-euclidean travel times), the semi-greedy algorithm allows us to have a basis of comparison for all tests, and reproduce the computations in an acceptable time period. Computational results are presented and discussed. Finally, recommendations to public authorities for their land-use policy assessment in terms of impacts on freight transport are proposed.

Background and context

The notion of accessibility has been used and analyzed since long time in urban transport planning but also in urban development analysis [START_REF] Gonzalez-Feliu | A double people-freight accessibility approach for urban retailing and leissure planning at strategic level[END_REF]. We observe in literature several definitions of accessibility, some of them derived into quantitative indicators, others related to qualitative studies. In our study, we aim to focus on the definition of Geurs and van Wee (2004) who defined accessibility as "the extent to which land-use and transport systems enable individuals to reach destinations by means of a transport mode". The authors identify four categories of accessibility indicators, mainly focused on personal transport.

The first category is that of infrastructure-based indicators, largely used in transport planning studies made by public authorities. These measures deal with service level related to a transport infrastructure, as for example the congestion level or the average travel speeds on a road network (Geurs and van Wee, 2004). The second is that of location-based measures, analyzing accessibility at physical locations, usually on a macroscopic perspective. The measures usually describe the level of accessibility to spatially distributed activities, and are largely used in urban planning and geographical studies. Two main groups of indicators can be distinguished in this category: distance based indicators and potential accessibility measures. The distance-based indicators, also called connectivity measures, represent the degree of which two locations are connected. Several distance measures can be defined, as for example the line distance between two points, other non-linear distance measures, the travel time or the transportation cost required to access a number of opportunities [START_REF] Ingram | The concept of accessibility: a search for an operational form[END_REF][START_REF] Pirie | Measuring accessibility: a review and proposal[END_REF]. The potential accessibility, also called gravity-based measures, estimate the accessibility of opportunities in zone i to all other zones. These measures take into account both the number of opportunities and the transportation costs to reach them (Geurs and van Wee, 2004). The third category contains person-based measures, which define accessibility at the individual level. This type of accessibility measures limitations on an individual's freedom of action in the environment. The fourth one is related to utility-based measures, which derive from the main benefits that people derive from access to the spatially distributed activities. This type of measure has its origin in economic studies, and interprets accessibility as the outcome of a set of transportation choices. Two main types of measures are used: logsum indicators, which study the desirability of the full choice set, and doubly constraint entropy models (Geurs and van Wee, 2004).

Regarding urban goods distribution, the gravity accessibility has been used to analyze the suitability of optimizing urban goods transport systems with cross-docking, relating them to vehicle routing optimization methods [START_REF] Gonzalez-Feliu | Models and Methods for the City Logistics -The Two-echelon Capacitated Vehicle Routing Problem[END_REF][START_REF] Gonzalez-Feliu | Freight distribution systems with cross-docking: a multidisciplinary analysis[END_REF][START_REF] Crainic | Two-echelon vehicle routing problem: a satellite location analysis[END_REF]. All authors define the opportunities as the quantity of freight to deliver, and no generalized costs are defined (only travel distances are considered). Since the works are carrier based and aim to study the suitability of route optimization approaches based on the only distance and cost factor, those indicators offer a good vision of the problem.

Concerning urban consolidation simulation, it has been traditionally modeled using vehicle routing approaches [START_REF] Toth | The vehicle routing problem[END_REF]. However, few works address the connection problems at consolidation centers, i.e. the relations between vehicles arriving and departing at each consolidation points [START_REF] Gonzalez-Feliu | Freight distribution systems with cross-docking: a multidisciplinary analysis[END_REF]. This is based on the assumption that urban consolidation centers are managed by different stakeholders than those shipping goods to UCCs, and that the coordination of all stakeholders is difficult and non-necessary for the good function of the platform [START_REF] Crainic | City Logistics[END_REF]. However, in collaborative systems, coordination and collaboration among all actors is crucial to the success of the distribution schemes (Gonzalez-Feliu and [START_REF] Gonzalez-Feliu | Collaborative transportation sharing: from theory to practice via a case study from France[END_REF] and VRP approaches combining two stages where in the first several transport carriers converge on consolidation platforms are needed. To the best of our knowledge, we observe only few works on it (Gonzalez-Feliu and Salanova, 2012; [START_REF] Thompson | A collaborative urban distribution network[END_REF]) and all cases consider that consolidation platforms are located.

Urban consolidation is a popular subject in urban logistics but, as shown by several authors, consolidation centres are often non-efficient and have difficulties to be deployed and maintained economically (Gonzalez-Feliu and [START_REF] Gonzalez-Feliu | Are City Logistics Solutions Sustainable? The Cityporto case[END_REF][START_REF] Zunder | Urban freight concepts and practice: would a traditional UCC scheme work?[END_REF][START_REF] Allen | The role of urban consolidation centres in sustainable freight transport[END_REF][START_REF] Morana | Urban Consolidation and Logistics Pooling[END_REF]. When regarding in-depth to the development of such platforms, its location has been a priori decided, without an analysis of the best area to locate it, and although some authors indicate accessibility analysis as a good tool to support such decisions [START_REF] Crainic | Two-echelon vehicle routing problem: a satellite location analysis[END_REF][START_REF] Gonzalez-Feliu | Models and Methods for the City Logistics -The Two-echelon Capacitated Vehicle Routing Problem[END_REF][START_REF] Gonzalez-Feliu | Freight distribution systems with cross-docking: a multidisciplinary analysis[END_REF] they use complex tools not able to be deployed by non-OR experts. To deal with lack, we aim to propose an accessibility analysis with an algorithm easy to deploy and tools easy to implement by non-OR experts.

The proposed framework

The proposed framework is an accessibility analysis based on a distance-based location accessibility indicator. The choice has been made because gravity indicators are based on O-D trips, which are direct trips, and in urban freight transport is organized in routes containing several trips.

First, the demand is estimated using a delivery-to-commodity model [START_REF] Gonzalez-Feliu | Determinants and variants in urban goods demand strategic modelling: commodity versus trip as data collection and modelling unit[END_REF]. The model works as follows. Given a city, divided into representative zones, we associate to each of them its population density, its commercial supply in terms of number of employees in each commercial activity class, its level of industry and distribution activity and its position with respect to the city center. Then we define a set of retailing activities that will be involved on logistics pooling strategies, for example the grocery distribution sector. Using a delivery generation model (Holguin-Veras et al., 2011;[START_REF] Gonzalez-Feliu | Determinants and variants in urban goods demand strategic modelling: commodity versus trip as data collection and modelling unit[END_REF], the number of deliveries per establishment can be estimated. Then, from Gonzalez-Feliu et al.'s (2012) ratios, we assign a quantity of freight to each establishment being delivered. The same procedure is made to each pickup.

After that, we define the accessibility indicator related to the location of each consolidation platform. The chosen accessibility indicator is the total traveled distance of all routes (from the 1st and 2nd echelon). To do this, we propose a sequential algorithm that works as follows: First, all customers are grouped, assigned then to a second-stage vehicle, using a Sweep algorithm. After that, each vehicle is assigned to a satellite (or cross-docking platform), taking into account the composition of the route and its total load. After that, a heuristic algorithm (either a semi-greedy or a genetic algorithm) is run to build second-stage routes, then, according to such routes, first stage vehicles are defined and corresponding routes built, using a dynamic programming approach (since the number of first-stage routes are small, a dynamic programming method can be run in realistic times and allows us to obtain more performing results than a heuristics procedure). Since the aim of the paper is to compare semi-greedy and genetic algorithms, we do not focus on the general algorithm structure but aim to detail both route construction algorithms.

After assigning customers to vehicles, a Semi-Greedy algorithm is built to build a first set of routes via a constructive procedure that adds each customer to a route. This algorithm is described more in-depth in [START_REF] Gonzalez-Feliu | Freight distribution systems with cross-docking: a multidisciplinary analysis[END_REF] and [START_REF] Gonzalez-Feliu | Defining and evaluating collaborative urban freight distribution systems[END_REF]. The semi-greedy algorithm is then improved by a combination of classical local-search heuristics, [START_REF] Toth | The vehicle routing problem[END_REF]. In the specific, we combine 2-opt, 3-opt, switch and or-opt moves. The algorithm has been tested in a set of instances [START_REF] Gonzalez-Feliu | Models and Methods for the City Logistics -The Two-echelon Capacitated Vehicle Routing Problem[END_REF] where optimal solutions are found [START_REF] Jepsen | A branch-and-cut algorithm for the symmetric two-echelon capacitated vehicle routing problem[END_REF]. We observe an important average gap. However, the aim of the paper is not to solve an optimization problem but to provide a quick indicator. The choice of this type of algorithm, which is not optimal but remains a quick way to estimate the total traveled distance, is motivated by two facts. The first is that we need a fast algorithm in order to simulate tens even hundreds of instances in few seconds, and the second is that we need to compare situations using the same basis, so this algorithm is fast and has a similar behavior if instances are similar (which is the case here). Moreover, the algorithm reproduces in a suitable way the driver's behavior and if we compare such routes to a set of real ones, we observe that the traveled distances and the composition of routes are similar to reality.

Once the algorithm is calibrated, we can define the scenarios to simulate. In this work we aim to compare different potential locations of consolidation and/or collaboration centers. Each scenarios is then assessed using the algorithm and a "distance-based" accessibility indicator is assigned. Then the accessibility analysis itself can be carried out. To do this, all scenarios are compared to state on the best location(s) of consolidation centers. To illustrate it, an example is shown in section 4.

Application results

To illustrate the proposed method, we present an example of application. We suppose 5 different operators (representing each a realistic transportation carrier). Each operator has a depot, located in a different area of the conurbation. The total number of customers is 136, but each of them is served by various operators, which makes a total number of 439 deliveries every day. Each operator has a different fleet of vehicles, composed by big and small trucks. Each operator has the same vehicles, respectively for big and small sizes, but their characteristics differ between operators. In order to propose a realistic set of scenarios, we used a real urban network: that of Lyon (France). If we aim to make them collaborate using the existing facilities, we have the choice among several consolidation platforms, located in the peripheral areas of the city. The city of Lyon has a particular configuration for which the South and the East are more industrialized areas where it is easier to find logistics platforms or terrains to develop urban consolidation facilities. The urban area is divided into 750 zones from where 148 are potential zones to locate a collaborative urban consolidation center. The demand of each customer is obtained using the method proposed in Gonzalez-Feliu and Salanova (2012).

Three groups of simulations are made. The first aims to locate one consolidation center among the different locations, the second two facilities, and the third three platforms. For each group of simulations the different possibilities are simulated, except (for the second and third set) those having two satellites at a very close distances and so being not convenient with respect to a solution with less satellites. For each scenario to simulate, the proposed algorithm estimates both big and small vehicle route distances, and calculates a distancebased accessibility indicator, defined as follows:

A i =100/d i
Where d i is the total traveled distance estimated with the proposed algorithm.

Figure 1. Map of the urban area for computational tests

We report in Table 3 the number of simulated scenarios for each group, as well as minimum, maximum, mean and medium values of accessibility. We observe that the most accessible scenarios are those of group 1. Indeed, it seems that, in the specific configuration and given the total daily demand to deliver to the chosen retailers of the inner city of Lyon (136 customers with a total commodity quantity of 27 508 kg), the configurations with only one consolidation center seem to be in average (and median) more accessible. Moreover, the minimum and maximum accessibilities are quite higher than those of the other two groups. Those exploratory results, which merit being further investigating and analyzing, show however that for the given customers and delivery quantities, the best configurations are those with a single consolidation center. This can be explained by two factors. The first is the quantity to deliver, which has to be related to the means given companies to deliver it (in the proposed simulation, no cost approach is made, only a distance-based analysis). Indeed, the delivered quantities are small but given the fleets of each operator, the concentration on a sole consolidation center is an suitable solution. However, this has to be confronted to the geographical characteristics of the urban territory. In this case, we have five carriers, each of them located in a different area of the conurbation. Since there is not a concentration of carriers in two points and all carriers serving all the city, in some cases delivering the same customers, the scenarios with one consolidation center allow each carrier to concentrate all deliveries on big trucks making direct shipping shuttle trips. If more than one consolidation center is defined, each carrier needs to deliver two or more points, and the demand distribution will make more or less difficult the entire distance optimization (if the demand to be delivered to one platform is higher than a truck capacity, the carrier will need to put a second truck, and eventually make routes, which will increase the traveled distances). Such distance increases are not always compensated by the reductions obtained in the terminal transport (from consolidation centers to customers) since traveled distances are higher in periphery than in the main city. Single-platform scenarios are then in average more suitable than multiple platform ones, and three-platform ones seem more compact (the differences between them are lower than in the other two groups, and mean and median are closer).

Conclusion

In this paper, we presented a method to support strategic decisions in terms of urban consolidation center's location. To do this, we propose a distance-based location accessibility indicator estimated via a semi-greedy algorithm to well show the route nature of freight transport in urban areas. The method allows to simulate the demand to transport via a commodity generation model, then to assess it into routes using a semi-greedy algorithm.

Finally, a distance-based accessibility indicator is calculated. Those results show that the method can identify, with a simple and quick method, the main accessibility issues for platform location and then anticipate risks and impacts of locating such facilities in the different parts of a city. To this, a practical example is made and a big quantity of scenarios are simulated and assessed by the method in order to produce comparative results and study the possibilities of location for urban consolidation platforms.

Finally, it is important to relate those results to practice. An accessibility analysis can state on the suitability or not of locating platforms and the proposed example show a result which is not always evident. Indeed, in urban areas of the size of Lyon we can envisage several platforms for urban distribution, but in the given example configurations with only one platform seem more suitable than configurations with more than one. However, it can be strategic for a public authority to define more than one platform. In this case, accessibility analysis can be interesting to choose a good and equilibrate configuration. In conclusion, we aim to remember that a decision support method is made to support decision makers in their choices, not to substitute them, so a decision maker must always have the freedom and possibility to choose the best solution that meets his or her targets, and such method need to help them to understand the impacts of such choices.

Table 1 .

 1 Summary of computational results on Gonzalez-Feliu (2008) instances

			Algorithm		Computational
	Group of instances Literature distance	distance	Gap	time
	20 customers	5.59	5.17	7.60%	0.08
	31 customers	8.98	7.89	12.19%	0.12
	50 customers	46.91	41.86	10.77%	0.11

Table 2 .

 2 Characteristics of the simulated operators

						Number of
	Operator	Number of Big vehicles Capacity	Number of small vehicles Capacity	customers
	1	2	7500	8	1200	95
	2	3	4000	12	750	115
	3	1	7500	5	1200	86
	4	2	4000	8	880	78
	5	4	2500	8	850	65

Table 3 .

 3 Synthesis of the three groups of simulation

	Group	of	Number	of	Min	Max	Mean	Median
	simulations		simulations		Accessibility	Accessibility	Accessibility	Accessibility
	1		148		1.8	11.0	4.4	4.1
	2		3248		1.5	9.3	3.9	3.9
	3		40403		1.5	8.9	4.0	4.0


Akiko Deguchi
email: deguchia@cc.utsunomiya-u.ac.jp

Shigenori Inagaki
email: inagakis@kobe-u.ac.jp

Fusako Kusunoki
email: kusunoki@tamabi.ac.jp

Etsuji Yamaguchi

Yoshiaki Takeda
email: takedayo@kobe-u.ac.jp

Masanori Sugimoto

Vegetation Interaction Game: Digital SUGOROKU of Vegetation Succession for Children

Keywords:

In this study, we redesign and develop a new digital sugoroku game based on the phenomenon of vegetation succession. A practical evaluation in an elementary school that consisted of game play and fieldwork activity was conducted. The results of the evaluation showed that the game was effective in stimulating the interest of the students who participated in the game, and was able to support their learning in a joyful way.

Introduction

Simulation games play an important role in the teaching and learning of science at school. They can support enjoyable interactive learning of complex systems in nature that are difficult to deal with in the school laboratory [START_REF] Squire | Augmented reality simulations on handheld computers[END_REF].

In our previous study, we have developed a simulation game, the "Vegetation Interaction Game" based on the vegetation succession, which is a digital sugoroku board game that simulates the real forest area of Mt. Rokko in Japan. In this sugoroku board game, a piece corresponds to a plant, and a grid of sugoroku to the relative succession phase around the plants. In playing the game, each child handles one piece. This condition supports children's playing the role of agent in the simulation. Moreover, we conducted an experimental evaluation in a university in Japan. The results showed the game was effective in stimulating the interest of students, and in supporting their learning in a joyful way [START_REF] Deguchi | Development and Evaluation of a Digital Vegetation Interaction Game for Children[END_REF].

In this study, we made some improvements in game interface to strengthen the enjoyability and understandability of the game. Additionally, we conducted a practical evaluation that consisted of two phases; game and fieldwork activity phase. This issue shows the development and improvement of our "Vegetation Interaction Game," and the results of practical evaluation. 6 players can participate in one game. Each player handles one piece. Players draw event cards, one at a time, by clicking in turn. When a plant piece advances ahead on the board grids, it implies that the plant is dominant in that particular environment. Each piece is to be moved by the number of grids that the current event card indicates. These directions are shown in the central part of the main window. If more than one piece takes the same position on the grid, they will be moved along the grids as indicated by the rules governing the interaction between plants. A game finishes when all event cards are drawn.

In this study, following points were improved based on the feedback of the previous experimental evaluation; (a) layout of the interface to make it more understandable, (b) illustration of event cards and visualization window to make them more scientifically valid and enjoyable for children.

Practical Evaluation of the Vegetation Interaction Game

The subjects were 17 sixth grade children (12 years old) in a Japanese elementary school. We recruited 18 children to participate in the experiment, and the participants were divided into three groups (6, 6, and 5) in random order (one child was absent on the experiment day). Game play was held in the elementary school (Fig. 2). Children played the game three times; in each game, the numbers of each event card were controlled so that children could experience some patterns of vegetation succession. After playing the games, the children had a fieldwork activity in Mt. Rokko area experiencing real vegetation succession along with the guidance of phytosociologist who is proficient at Mt. Rokko area (Fig. 3).

Evaluation of Students' Interests

After the game play, children answered the questionnaire about the game. Table 1 shows the question items and their results. To examine the children's answers, "think so" and "quite think so" were evaluated as a positive answer, "no opinion," "don't quite think so" and "don't think so" were evaluated as a negative answer. After that, Fisher's exact test was conducted. The results show that positive answers were significantly higher than negative ones in all the items. Table 1 Results of students' interests TS; Think so, QTS; Quite think so, NO; No opinion, DQTS; Don't quite think so, DTS; Don't think so, ** p<0.1

Conclusion

In this study, we redesigned and developed a Vegetation Interaction Game and conducted a practical evaluation that include fieldwork activity. The results of evaluation showed that children who participated in the experiment felt the game was interesting and they also thought that they understood the mechanisms of vegetation succession. It was shown that the game could successfully communicate with students, and was able to support their understanding of the relationship between disturbance and the numbers of each plant.

Figure 1

 1 Figure 1 is the main window of the digital game; it shows the face of the sugoroku board. 6 plant pieces represent 6 characteristic plants that grow in the Mt. Rokko region. The size of the sugoroku board was set at 1024*768 pixels. The surrounding part is the grid area of the sugoroku board. The central part houses the event cards area, a direction window to move pieces, and a visualization window to show vegetation succession according to the progress of the game.6 players can participate in one game. Each player handles one piece. Players draw event cards, one at a time, by clicking in turn. When a plant piece advances ahead on the board grids, it implies that the plant is dominant in that particular environment. Each piece is to be moved by the number of grids that the current event card indicates. These directions are shown in the central part of the main window. If more than one piece takes the same position on the grid, they will be moved along the grids as indicated by the rules governing the interaction between plants. A game finishes when all event cards are drawn.In this study, following points were improved based on the feedback of the previous experimental evaluation; (a) layout of the interface to make it more understandable, (b) illustration of event cards and visualization window to make them more scientifically valid and enjoyable for children.

Fig. 1 .

 1 Fig. 1. Main window of sugoroku board

  was absorbed in playing the game. understand the relation between disturbances and the number of the kinds of plants.

Acknowledgement

This research is supported by Grants-in-Aid for Scientific Research (B) for Masanori Sugimoto, and Hayao Nakayama Foundation for Science & Technology and Culture for Akiko Deguchi.


Tsutomu Terada
email: tsutomu@eedept.kobe-u.ac.jp

Kohei Tanaka
email: tanaka.kohei@ist.osaka-u.ac.jp

A Framework for Constructing Entertainment Contents using Flash and Wearable Sensors

Keywords: Wearable Computing, Flash, Development Environments

Multimedia interactive contents that can be controlled by user's motion attract a great deal of attention especially in entertainment such as gesture-based games. A system that provides such interactive contents detects the human motions using several body-worn sensors. To develop such a system, the contents creator must have enough knowledge about various sensors. In addition, since sensors and contents are deeply associated in contents, it is difficult to change/add sensors for such contents. In this paper, we propose a framework that helps contents creators who do not have enough knowledge on sensors. In our framework, an interactive content is divided into two layers; sensor management layer and content layer. We confirmed that creators can create interactive contents easier with our framework.

Introduction

In recent years, the importance of intuitive human-computer interfaces has increased and increased. Especially, Nintendo Wii that is a video game console released in 2006 infuses new breath into the game market since we can play video games intuitively by using sensor-enabled game controller as a sword and a tennis racket. On the other hand, it is still difficult for contents creators who create contents using Flash or other animation tools to develop such contents since they usually do not have the knowledge to manage sensors and to recognize user's motion from raw sensor data. Moreover, once the contents creator made a content using sensors, it is difficult to change the sensors used in contents because the sensor management is deeply integrated to the contents. Therefore, there is a requirement on the support for contents creation by easier sensors managements.

Here, Flash [START_REF]Flash CS4[END_REF] is so popular for providing interactive contents on web browsers. Flash contents have various advantages such as small file size with respect to rich contents, and support for various platforms (more than 99% people in mature market can play flash contents). Contents creators can implements interactivity on the contents using easy programming scripts called ActionScript. The remainder of this paper is organized as the follows. Section 2 describes our environmental assumptions and Section 3 presents related works. Section 4 describes the process of developping contents using our framework. We explain our framework in detail in Section 5 and discuss our framework in Section 6. Finally, we conclude this paper in Section 7.

Environmental assumption

The target users of our framework are flash contents creators that do not have enough knowledge how to use the sensor data while they can create flash contents without sensors. Recent days, there are many people that can create flash contents since flash becomes popular.

We employ Wearable toolkit that we developed to define/recognize user contexts. It consists of an event-driven rule processing engine and several plug-ins to implement context-aware applications easily. The rule in the toolkit is called ECA rule, which consists of Event, Condition, and Action. For example, when we want to develop the system that displays the train schedule when user arrives at the station, we define the reception of GPS data as Event, the comparison the current position with the position of station as Condition, and the navigation to web site as Action, as shown in Figure 1. Wearable toolkit has Context Definition Tool that users define user contexts easily by actually demonstrating the motion to be registered. The rule engine raises an event when it detects the similar motions to registered contexts. The Context Definition Tool supports various sensors such as 3-axis acceleration sensors, temperature sensors, a GPS, and RFID tag readers. Figure 2 shows an example of our assumed content and user. The user interacts with the content by his motions in front of the screen. He receives feedbacks by the screen, sound, and some actuators.

Related works

There are many researches to develop services using various sensors and actuators. Phigets [START_REF]Phidgets[END_REF] and Teleo [2] are toolkits that consist of various sensors and actu-

Body-worn sensors

Interactive content

Fig. 2. An example of playing contents ators to develop applications using the libraries in various development environments. Gainer [START_REF] Kobayashi | Gainer: A reconfigurable I/O module and software libraries for education[END_REF] is a hardware platform to connect various devices to computer. GlovePIE [1] is a tool for assigning device functions to application functions by a script language. Using these toolkits, we can develop applications that use various devices easily. However, we still need to know how to process the sensor data since they support only connection between computer and devices.

A CAPpella [START_REF] Dey | a Cappella: Programming by demonstration of context-aware applications[END_REF] enables us to define user actions easily, and GT2K [START_REF] Westeyn | Georgia Tech Gesture toolkit: Supporting Experiments in Gesture Recognition[END_REF], AR-Toolkit [START_REF] Kato | Virtual Object Manipulation on a Table-Top AR Environment[END_REF], and DART [START_REF] Macintyre | DART: A toolkit for Rapid Design Exploration of Augmented Reality Experiences[END_REF] provide the recognition of gestures and markers by camera. However, these systems does not refer to programming model.

Contents development with our framework

We show an actual development of interactive game, a 110m hurdles game, as the following steps. Our framework especially supports Step 2, 3, and 4 since these steps are difficult for contents creators.

Step 1 Contents design Step 2 Motion registratoin Step 3 Rules description

Step 4 Flash contents creation

Step 5 Debug

Step 1 Contents design: We established the overall picture of the contents in this step. Then, We discussed the purpose of the contents, motions to be used, and required sensors and actuators. In this case, the purpose of the game is to compete the time from start to goal. The character on the flash contents runs while the player runs, it stops when the player stops, and it jumps when the player jumps. Moreover, a vibrator works when the character fails to jump a hurdle.

Step 2 Motion registratoin: Next, we registered the player's motions that are designed in previous step using Context Definition Tool. To register them, we only performed the actual motions. We also confirmed that the actions can be recognized accurately. For this game, we registered the 3 motions; run, stop, and jump.

Step 3 Rules description: In this step, we described the rules for Wearable Toolkit to communicate with flash contents. Our Code Generation Tool, which is explained in the following section, produces the rules by inputting the relationship between user actions and flash scripts that are activated when the motions are recognized. Concretely, to create the rules about run action, we input the name of running action and a script that is executed at running. The Code Generation Tool generates the scripts and the rules to execute the input scripts when the system recognizes run. We also input descriptions about stop and jump. In the same way, we also easily get the scripts and the rules to control actuators by Code Generation Tool. In concrete, we selected the vibrating function from the list of Wearable Toolkit functions, then the named of the function can be used in flash contents.

Step 4 Flash contents creation: In this step, we created flash animation contents. The Code Generation Tool generated flash project file in which the script for communication is already described. To control an actuator, we only describe RaiseEvent() function that has the event name selected in the previous step. We added RaiseEvent() function in the script code for collision detection.

Step 5 Debug: We tested the contents using the debugger of Wearable Toolkit. Using this debugger, we confirmed that flash received the player motion events and Wearable Toolkit received the device control events. Moreover, we checked the accuracy in motion recognition. When the accuracy is not enough, we change the threshold in recognition or redefine the motions. We can change the content easily since Code Generation Tool generates rules and scripts independently from actions and actuators.

Design of framework

Our framework consists of 2 layers as shown in Figure 3. Sensor management layer manages sensors and actuators, and recognizes user motions. Flash contents layer is flash contents including several templates to communicate with the other layer. Since it is difficult for flash creator to use the sensor data directly, our framework hides the sensor management layer from contents creators. If they define the user motions that they want to use semi-automatically using Context Definition Tool, flash contents can receive the motion-recognition event from sensor management layer.

In this research, we add a function for communicating with flash contents to Wearable toolkit and implement Code Generation Tool that generates the rules and the scripts for associating motions with actions.

✓ ✏

RegisterAction( "ACTION_NAME", OnAction, "explanation", "type of argument"); RegisterEvent( "EVENT_NAME", "explanation", "type of argument"); function OnAction(Arg:type of argument){ //OnAction implementation Here } ✒ ✑ Fig.

4

. An example of script at initialization

To realize the communication between Wearable Toolkit and flash contents, we utilize the Flash Player's commands that are originally used for communication with Flash Player and the contents. Although this command cannot transfer without text message, it has enough capability to send context information to flash contents and we do not suppose the contents creators use the raw data from sensors. The communication between Wearable toolkit and flash occurs in the following three situations:

Communication on flash contents starting: First communication occurs in initializing the content. When a flash content starts, it sends messages to Wearable Toolkit to register user motions and actuators to be used via fscommand() function [START_REF]Adobe: Actionscript 2.0 components lauguage reference[END_REF]. This process is based on the code shown in Figure 4, which is generated by Code Generation Tool. This process includes the association between motions and scripts. In the figure, ACTION_NAME action is associated with OnAction() function. When the toolkit receives the messages, it registers the messages as events or actions. Communication when user motion is recognized: After the flash content starts, Wearable Toolkit recognizes user motions from sensor data. When a motion is recognized, ECA rules that are generated by Code Generation Tool are executed to send the recognition results to the flash content. The flash content calls the associated scripts according to the received results.

An example of such ECA rule is shown in Figure 5. This rule is activated when the context named CONTEXT_NAME is recognized, and sends the function name ACTION_NAME to exectute the script in the flash content. This rule is automatically generated by Code Generation Tool.

To realize this communication, FLASH_ACTION action calls SetVariable() function [START_REF]Developer connection[END_REF] on the SWFobject, which is a function to change the value of variables on the flash content. In the content, the target scripts are described as a callback function. In the example of Figure 4, OnAction() is executed when the value of the variable is changed to ACTION_NAME.

Communication when the content controls actuators: Our framework enables flash contents to control actuators by fscommand() function in the contents that sends text messages to Wearable toolkit. The ECA rules for actuators control in Wearable toolkit, which is created by our Code Generation Tool, receive commands and control the associated actuators. An example of the ECA rules is shown in Figure 6. The rule in the figure execute CONTROL_ACTUATOR() action to control an actuator when the command named EVENT_NAME is received via fscommand() from the flash content.

Consideration on implementation time

We discuss the easiness of contents development by using our framework. Firstly, we implemented an interactive game by modifying existing breakout game. We associated two motions on the game with two physical motions. We took less than one hour to modify this game.

Next, we implemented two games that are the homerun chase game and the swimming game. In the homerun chase game, to swing the bat on game, a user Figure 7 shows snapshots of these games.

In addition, we created a content for donation box at Kobe Luminarie that is a festival held in Kobe, JAPAN. The festival is held to mourn the victims. We developed the content on the display in front of the donation box. The dog character in the content performs the same motion as a person who fold the donation box. For example, when the person bows, the dog on the display also bows and says, "Thank you for your donation" as shown in Figure 8.

This contents was also developed in approximately three hours. From these implementations, there is little time to implement interactive contents using sensors by our framework.

Conclusions

In this research, we proposed and implemented a framework that enables contents creators to create interactive contents using wearable sensors. The framework presents the mechanism for communication between Wearable toolkit and flash contents. Moreover, our proposed Code Generation Tool achieved automatic scripts/rules generation to use our framework easily. We confirmed that contents creator could develop intuitive contents in a few hours by evaluating actual implementations.

On the other hand, we feel that the difficulty of games becomes higher since the gesture input is difficult and delayed compared with the conventional input methods. Thus, we should adjust the game difficulty according to the recognition accuracy and the delay of the motion. In the future, we will evaluate our framework based on actual implementations by flash content creators to show the effectiveness on complicated interactive contents.

Fig. 5 .Fig. 6 .

 56 Fig. 5. An example of ECA rule to send a message to the flash content ✓ ✏ WHEN FLASH_EVENT('EVENT_NAME') THEN DO CONTOL_ACTUATOR() ✒ ✑ Fig. 6. An example of ECA rule to control actuators

Fig. 7 .

 7 Fig. 7. Created games

Fig. 8 .

 8 Fig. 8. Snapshots of the content in donation box

  An example of ECA rulepropose a framework for flash creators to create interactive contents with sensors and actuators. Our framework provides several tools to hide the difficulty in sensor management and creators can create interactive contents by ActionsScript easily.

	✓ WHEN GPS_MOVE	✏
	IF CURRENT.Position == 'station'
	THEN DO BROWSER_OPEN('URL') ✒	✑
	Fig. 1.
		Thus, we


Erik Puik

Leo Van Moergestel

Agile Multi-Parallel Micro Manufacturing Using a Grid of Equiplets

Keywords: Grid Manufacturing, Agile, Reconfigurable, Equiplet, Production, Micro, Microsystem, Hybrid, Submissive Product Design

Unlike manufacturing technology for semiconductors and printed circuit boards, the market for traditional micro assembly lacks a clear public roadmap. More agile manufacturing strategies are needed in an environment in which dealing with change becomes a rule instead of an exception. In this paper, an attempt is made to bring production with universal micro assembly cells to the next level. This is realised by placing a larger number of cells, called Equiplets, in a "Grid". Equiplets are compact and low-cost manufacturing platforms that can be reconfigured to a broad number of applications.

Benchmarking Equiplet production has shown reduced time to market and a smooth transition from R&D to Manufacturing. When higher production volumes are needed, more systems c a n b e p l a c e d i n p a r a l l e l t o m e e t t h e manufacturing demand. Costs of product design changes in the later stage of industrialisation have been reduced due to the modular production in grids, which allows the final design freeze to be postponed as late as possible. The need for invested capital is also pushed backwards accordingly.

Introduction

This research focuses on manufacturing of "Hybrid Microsystems". Hybrid systems are composed of multiple elements to realise their primary function [START_REF] Kear | Hybrid assemblies and multichip modules[END_REF][START_REF] Tichem | A DFA Framework for Hybrid Microsystems[END_REF]. Hybrid Microsystems combine multiple functional domains; electronic, mechanical, optical, fluidic or biomedical domains may be included. Though all these different systems share many of the same underlying technologies, the use of micro technology is typically application specific and mainly used for sensors and actuators. This is the reason why Hybrid Microsystems address, a limited number of mass applications excepted, mainly niche markets.

Manufacturing of products for niche markets with numbers in the mid size volume area, in between 10 4 -10 7 products annually, is not easy from an efficiency point of view. Dedicated equipment for manufacturing requires high added value at these relatively small production series. Manual production on the other hand strongly relies on labour, which not only is expensive, but also could suffer from quality issues in the high-tech systems markets with its strict quality demands.

Manufacturing context for Micro Systems

Disruptions during ramp up of production in the micro domain

Manufacturing accuracies for assembly operations in the micro domain are constantly evolving. Since micro system manufacturing, in the lower and mid volume domain, is traditionally relying on an extensive amount of manual labour. Supporting assembly tools are typically used, to enable manual workers, in meeting the high accuracies of production. Once fully ramped up, production equipment has been developed and produced. In the move from early production to the ramped up situation, a transition is made from manual production to (semi) automated production. This transition, with large impact on process stability and product quality, is made at some point in which market introduction is at sight, a moment when invested capital and project risks are rapidly increasing. Unexpected delays at this point, due to the disruptions of this manufacturing transition, will almost certainly lead to delayed market introduction [START_REF] Moore | Inside the Tornado: Strategies for Developing, Leveraging, and Surviving Hypergrowth Markets[END_REF].

To avoid the disruptions during ramp-up, applied equipment is preferably to remain unchanged during the transition from R&D to full production. This would be the case if assembly tools during R&D stage, or at least the assembly principle and the conditions under which they are performed, could be reused for semi automated production and later eventually even automated production. Attempts have been made in the past to realise this way of working [START_REF] Schünemann | Automatisierte Montage und Justage von Mikrokomponenten[END_REF][START_REF] Grosser | A fabrication Framework for Modular Microsystems[END_REF][START_REF] Eupass | EUPASS External Progress Report[END_REF][START_REF] Puik | A Lower Threshold to the World by Combining a Modular Design Approach and a Matching Production Framework[END_REF].

Re-configurability

Unlike manufacturing technology for semiconductors and printed circuit boards (PCB), the market for traditional micro assembly lacks a clear public roadmap [START_REF] Gutierrez | MEMS/MST Fabrication Technology based on Microbricks: A Strategy for Industry Growth[END_REF][START_REF] Becker | Micro-and Nanotechnologies for Advanced Packaging[END_REF][START_REF] Heeren | Worldwide Services and Infrastructure for Microproduction[END_REF]. It is due to the larger variety of processes and the three dimensional characteristics of micro assembly that the technology will not fit into a single manufacturing framework. Due to the high added value of many manufacturing processes, dedicated manufacturing systems have proven to be legitimate in micro manufacturing, even if the manufacturing technology is intrinsically less efficient. On the other hand, many products with lower economic potential don't make it to the market because for this reason. It is the potential of reusing existing manufacturing technology that increases the popularity of flexible equipment. Many suppliers of state of the art equipment offer systems that can be configured in a flexible way to form a dedicated manufacturing system. Problems however occur when these systems have to be converted to changing products. Usually machines are shipped back to the factory to be modified (upgraded). This ceases actual production, which generally is not acceptable. Therefore the choice is often made to replace the equipment and invest in new systems, leaving the existing systems untouched till the new system is up and running. If existing equipment would be gradually upgradable, in a true re-configurable sense, investments in equipment could be reduced significantly.

Agile manufacturing

The manufacturing environments of present and next decades differ substantially from the past. Technology and consumer markets have become extremely difficult, posing difficulties for the use of traditional top-down planning-based methods for developing manufacturing strategies. More agile manufacturing strategies are needed in an environment in which dealing with change be c ome s a rule instead of an exception [START_REF] Gunasekaran | Agile Manufacturing as the 21st Century Strategy for Improving Manufacturing Competitiveness[END_REF].

Manufacturing Technology is regarded as one of the most important decision areas within the manufacturing management function. Traditionally, management has influenced manufacturing technology to a much greater extent than the other way round. To have a revolutionary manufacturing concept adopted, one of the aims of this manufacturing strategy is to give the organisation strategic direction with regard to manufacturing issues. This direction should include technology, people and infrastructure, used in a consistent way, with the strategic objectives of the business [START_REF] Goldhar | Plan for Economies of Scope[END_REF][START_REF] Stecke | Production Flexibilities and their Impact on Manufacturing Strategy[END_REF]. In a future world, where change is a certainty, all company's resources should work together closely to deal with unplanned change. Basically there are only two ways of handling this, being in control or being flexible. In this context it is hard to imagine how traditional dedicated equipment would suffice the needs for the future.

Submissive Product Design

To improve reuse of technology, during the transformation from R&D to full-scale manufacturing, a distinct conformity has to be realised between product design and manufacturing processes [START_REF] Salomon | Design for Micro & Nano Manufacture[END_REF]. This could lead to more cost effective, gradual and lowthreshold industrialisation of micro systems [START_REF] Puik | A Lower Threshold to the World by Combining a Modular Design Approach and a Matching Production Framework[END_REF][START_REF] Gutierrez | MEMS/MST Fabrication Technology based on Microbricks: A Strategy for Industry Growth[END_REF]. Basically, this way of working is based on the application of design rules that have been strongly submitted to the available production framework of the manufacturing facility. Submissive Product Design can be seen as a fortified implementation of DFA (Design For Assembly) in the micro domain. With Submissive Product Design, manufacturing technology is unceasingly leading over the Product Design. If applied conformably through the industrialisation processes, manufacturing complexity will be disentangled into basic assembly operations [START_REF] Gutierrez | MEMS/MST Fabrication Technology based on Microbricks: A Strategy for Industry Growth[END_REF]. This means the use of a larger number of machines with less complex assembly operations. The assembly operations would still require leading edge manufacturing technology, but less assembly research is needed to implement the technology in manufacturing equipment. This paves the opportunities for standardisation, and the much aimed for, reuse of manufacturing technology.

Multi Parallel Micro Manufacturing; "Grid Manufacturing"

Production in the micro domain using "Equiplets"

Typical required accuracies in the micro assembly domain exceed the achievable accuracies of manual labour when performed without any some of instrumentation. With straightforward assembly tools a significant gain in quality of high performance assembly operations can be achieved. The application o f m a n u a l l a b o u r h a s disadvantages too, mainly in achieving constant & guaranteed accuracies. This preferably would limit manual intervention of operators to the logistical part of the assembly, like handling parts in trays [START_REF] Hollis | Agile Assembly Architecture: A Platform Technology[END_REF][START_REF] Koelemeijer-Chollet | Cost Modelling of Microassembly[END_REF]. The need for increased production conformity, or yield, leads to the implementation of (universal) micro assembly cells. Much effort has been performed to design these universal assembly cells that meet the agility of human operators [START_REF] Hollis | Agile Assembly Architecture: A Platform Technology[END_REF][START_REF] Mardanov | An Automated Assembly System for a Microassembly Station[END_REF][START_REF] Hollis | Miniature Factories for Precision Assembly[END_REF][START_REF] Yang | A Flexible Experimental Workcell for Efficient and Reliable Wafer-Level 3D Microassembly[END_REF][START_REF] Fahlbush | Flexible Microrobotic System MINIMAN: Design, Actuation Principle and Control[END_REF][START_REF] Zhou | Microassembly System with Controlled Environment[END_REF][START_REF] Kim | Flexible Microassembly System on Hybrid Manipulation Scheme[END_REF][START_REF] Gaugel | Building a Mini-Assembly System from a Technology Construction Kit[END_REF][START_REF] Tanaka | Development of Desktop Machining Microfactory[END_REF][START_REF] Lauwers | Progress in Agile Assembly: Minifactory Couriers Based on Free-Roaming Planar Motors[END_REF][START_REF] Clévy | Micromanipulation and Micro-Assembly Systems[END_REF][START_REF] Cecil | Development of a Virtual and Physical Work Cell to Assemble Micro Devices[END_REF]. Secondly, cost analyses have been performed to justify the application of these cells in an economical context [START_REF] Koelemeijer-Chollet | Cost Modelling of Microassembly[END_REF][START_REF] Koelemeijer-Chollet | Economical Justification of Flexible Microassembly Cells[END_REF][START_REF] Koelemeijer-Chollet | A Flexible Microassembly Cell for Smal and Medium Sized Batches[END_REF]. These efforts have been successful, in a way that universal micro assembly cells can be feasible from a technological and economical perspective. The throughput of these systems however has not exceeded mid-volume production quantities. In this paper, an attempt is made to bring production with universal micro assembly cells to the next level. This is done by placing a larger number of cells in a "Grid" (4-100 + systems). The universal assembly platforms, which are field reconfigurable, are called "Equiplets". Equiplets are compact and low-cost manufacturing platforms that can be reconfigured to a broad number of applications by adding product dependent tools. These tools are very similar as the tools that are used during R&D and for the manufacturing of pre-production series.

Using Equiplets in production has advantages and drawbacks. These are compared in the next chapter. Two advantages may be seen as the main drivers for applying Equiplets:

• Reduction of risks during Ramp-up. The transition from "R&D-Pilot Production-Automated Production" can be made without disrupting production technology. Optimal consistency through these phases is achieved, minimising risks of non functioning production technology; • Flexibility gain in the application of production resources. Due to the truly reconfigurable character of Equiplets, and also due to the larger number of Equiplets present in a factory, it is possible to "balance" regular production with the actual production demand. This could be used to balance different production stages of one product, but can also be used to balance production demand over a number of different products to be produced at the same factory.

Picture 1-3: Equiplets in R&D environment. Equiplets are easy to reconfigure due to the modular structure. Ready for production (left) or for a quick test (right), the structure allows experimenting. With an agent based control system, self-learning is an option for the future to further increase accessibility (middle)

Dynamics of manufacturing in grids

Analogue to "Grid Computing", where time consuming computer tasks are divided over many computing hardware systems, it is also possible for manufacturing tasks to be distributed over a larger number of production systems. It may be clear that, due to the character of micro assembly, the dynamics of tuning the grid to adapt to changing demand for manufacturing will be of another order than software computing grids. Grid refinement for manufacturing will more likely be on a daily basis (compared to seconds in grid computing). This however is a breakthrough in flexibility compared to dedicated equipment, where substantial equipment upgrades are in the magnitude of months.

Manufacturing tasks are very different from computing tasks in a sense that the adapting the manufacturing grid to start another product cannot always be done in software alone. Note that re-configurability in this context does not mean that the production system is suitable for all thinkable production demands. This is the main reason why manufacturing in grids can only be successful if combined with a solid design strategy like DFA or better "Submissive Product Design". Although some product switches, especially switches within the same product family, can be done by changing the software jobs alone, it is however most likely to have a combined software and hardware modifications.

Modern adaptive controller architectures, based on software agents, support flexibility and speed of re-configuration, this will be addressed in a future paper.

Benchmarking Equiplet production with State of the Art Manufacturing Equipment

In this chapter, Grid Manufacturing with Equiplets is compared with state of the art manufacturing solutions on the following topics: • Time to market; • Investment risks; • Production agility;

• A last topic, to be covered is "Cost Modelling" research. Some basics will be explained in this document, a deeper cost modelling analysis is planned for a near future publication. This will cover issues like cost of ownership, but also up front investing in flexibility that might payback later.

Time to market, time to volume

Industrialisation of new product developments usually starts with a limited number of R&D prototypes, realised by R&D engineers, to mainly serve for testing of functionality of the product. R&D engineers are usually no experts on manufacturing, which causes the need to optimise the product design for industrialisation. The traditional approach, till some 20 years ago, tended to be fully sequential, but since the 90's, concurrent engineering strategies have appeared to be more efficient. The overlap of R&D "proof of concept" and "manufacturing engineering" leads to quicker industrialisation, bringing problems due to the up scaling process to the surface in an earlier stage. This while manufacturing investments are still low thus keeping financial risks acceptable. The early involvement of manufacturing engineers leads to more optimised manufacturing processes that are upgradable to reasonable extent. Traditional high volume production with dedicated equipment however, would still need a redefinition of production process and equipment, causing the need for an "equipment feasibility" phase followed by a certain timeframe in which equipment is being engineered and realised (figure 1). Pilot production cannot start before these phases have been completed.

If however the manufacturing of prototypes could be structurally upgraded by the introduction of robotised equipment, manually-or tele-operated in the R&D phase, the technological basis of the production processes would automatically meet the demand for automated manufacturing. In the transition to pilot production, human commands would be gradually replaced by software automation, offering a seamless path to pilot production. As a rule of thumb, it should be envisioned from a manufacturing point of view, that it is not desirable to perform manual operations to prototypes during the R&D phase, but that the operations always should be performed by equipment, or simple reconfigurable equipment, which leads to the use of Equiplets during the entire development and industrialisation phases. Without this dedication the advantages will be gradually reduced to a point in which industrialisation is typically performed sequential, analogue to today's standards.

It will need no explanation that manufacturing in a grid works best when the attitude of R&D engineers is cooperative. As stated in chapter 2, this calls for an increased level of management involvement, which should aim on technology and people as well as the necessary infrastructure. A positive stimulant, to optimise R&D involvement with Equiplets during early phases, is the energy it usually takes to realise prototypes and demonstrators in the early development stage. Especially in the micro domain, this usually absorbs significant amounts of resources. By using robotised equipment in the early stage, the numbers produced could be increased at minimal cost, providing more and also better quality prototypes supporting the research process.

The last point of attention is the process of ramping up to higher volumes. In a traditional way this would be typically done by increasing uptime and the speed of the dedicated production machine. In the case of Equiplet production this is basically the same, under the constraint that the maximum speed of a Equiplet production line will be structurally lower than the well engineered and state-of the art built production machine. This would mean that when the maximum throughput of one production line has been reached, the next step would be to increase the number of production systems that operate in parallel. A major advantage is that the investments in more parallel production lines only has to be sustained when the market demand indeed reaches the next level. If a product appears less successful or has been delayed, according investments can be postponed. If a product is extremely successful, more machines can be configured on fairly short notice, since the complexity of the Equiplets is low due to the decomposition of technology over a larger number of machines. In this way, a manufacturing plant always fits the actual demand (figure 2).

Investment risks

In chapter 2.3 was stated that manufacturing technology is regarded as one of the most important decision areas within the manufacturing management function [START_REF] Gunasekaran | Agile Manufacturing as the 21st Century Strategy for Improving Manufacturing Competitiveness[END_REF]. Though this true, and there is no shortage on management involvement for manufacturing departments, the moment that the involvement takes place is often timed badly. Management involvement typically increases when the investments are Figure 2: Volume production can be adjusted to market demand, requesting investments tot be done no earlier than revenues start increasing. In this way, investment risks are minimised on the urge of rapid increase. This is when R&D is in the Proof of Concept Phase [START_REF] Roussel | Third Generation R & D: Managing the Link to Corporate Strategy[END_REF] (figure 3). The problem however is that at this point many design issues, and related manufacturing demands, have already been chosen and the costs for industrialisation have been intrinsically determined.

A basic difficulty with manufacturing equipment is that the manufacturing means have to be determined developed and invested up front. With the engineering and realisation of manufacturing equipment, the product design will be frozen except for the exact specified (foreseen) variations within a product family. This is the main reason that the "Cost of Change" for dedicated equipment, as given in figure 3, increases so quickly. Once production has started, problems even get worse, because the manufacturing process has to be shut down to bring product modifications in effect, putting pressure on revenues. How different will manufacturing be if possible to incorporate a growth strategy with parallel production platforms. With manufacturing in grids this can be achieved after product launch to grow to a certain turnover, but production is still flexible when the product is over the top and markets are slowly shrinking. Manufacturing capacity can be matched to meet product demand in a number of discrete steps. Applying the Equiplet manufacturing strategy will also limit overcapacity on the production floor (see table 1). After reaching the top of sales, production can be reduced using a limited number of production lines. The other manufacturing lines will be reconfigured to support a quick growing new product. In this sense it is constantly possible to tune the actual production to the exact demand.

Grid Agility

The manufacturing agility when applying grid manufacturing is improved by two main characteristics: A. The Equiplets are reconfigurable, having all advantages of reconfigurable equipment; B. The Grid structure is used to create form-fit production facility. The higher number of systems lead to fairly accurate adjustment to market demand (see table 1).

Figure 3: Invested capital leads to increases of the cost for design changes of the product. Typically management involvement increases when facing the Process Engineering stage (halfway the graph). Influences to the Design Performance has drastically reduced

Ad A. Reconfigurable equipment combine productivity with acceptable cost in various volume demands [START_REF] Dashchenko | General RMS Characteristics. Comparison with Dedicated and Flexible Systems[END_REF]. Reconfigurable machines however are not the holy grail of manufacturing automation, but a efficient means for manufacturing products that serve a dynamic market and suffer from short life cycles (i.e. high end electronics, cellphones, PDA, gaming platforms). Once configured reconfigurable equipment acts as a dedicated machine for some amount of time.

Ad B. Manufacturing in Grids will add flexibility, because a larger number of machines will be divided over a number of products to be manufactured. How this works is shown in the next example (table 2):

In February 2010 a new product (I) will be launched that requires two processing operations of type A, three operations of type B and two operations of type C. In February 2010 a total number of eight Equiplets will take care of the production. Two of them will be configured as operation A, three as operation B another two as operation C (2A-3B-2C). A half-year later, market demand has increased, the production scheme now has become 4A-6B-5C. The same month a second product is launched (II). Again some Equiplets are configured to meet production demand. February 2011, the first reconfiguring action takes place. Two Equiplets, configured for operation A, are converted to operation D. Half a year later all Equiplets type A, and one of type B, have been reconfigured tot D. And so on.

In this case the factory floor grows to a number of roughly 50 Equiplets that are continuously converted to new production operations to meet the manufacturing demand for each actual product (A to D). Every now and then a machine is converted to another operation, causing minimal downtime, since the rest of the grid continues production. Machines are not necessarily logistically coupled to physical production lines, which is usually not interesting for the micro domain [START_REF] Koelemeijer-Chollet | Cost Modelling of Microassembly[END_REF]. Adding logistical systems, conveyors, tray handlers etc, could however be economically feasible, especially near completion of the product when physical product volumes increase. The example shows the excellent flexibility of the manufacturing grid, where transformation from one to another product can take place with minimal downtime. After initial configuration, the advantages get bigger when the reconfiguration takes place, since from that moment on, reuse of technology and investments contributes to more efficient application of resources. Again, the need for an effective DFA strategy should be emphasised. Since quick launch of production, as well as successful reconfiguration, only can succeed in close cooperation with R&D people.

Cost Modelling

Though in the past some cost modelling on micro production cells has been performed [START_REF] Koelemeijer-Chollet | Cost Modelling of Microassembly[END_REF][START_REF] Koelemeijer-Chollet | Economical Justification of Flexible Microassembly Cells[END_REF][START_REF] Koelemeijer-Chollet | A Flexible Microassembly Cell for Smal and Medium Sized Batches[END_REF] there is no extensive literature on this topic available. Some first facts from literature: • There is little or no need to invest in the automation of logistics. In view of weight and size it will be more cost effective to have operator bring parts to the machines in containers; • Components need to be kept in batches, like trays, wafers or SMIF boxes to maintain orientation of products. This suppresses the need for realignment in every station; • It may be expected that cost models will lead to new design rules for the set-up of micro factories; • Cycle time remains an important factor, since its reduction directly leads to less equipment on the factory floor; • Floor space could be a bottleneck. Dedicated equipment with a high engineering level is efficient on floor space. Microsystems manufacturing regularly take place under clean room environments, which lead to high cost of floor space. Though the footprint of the Equiplets will be small, a large number of them will be less efficient in comparison to dedicated machines.

Conclusions

The application of dedicated equipment causes disruptions during transformation of the product from R&D to the manufacturing phase. To avoid the disruptions during ramp-up, applied equipment is preferably to remain unchanged during the transition from R&D to full production. This would be the case if assembly tools during R&D stage, or at least the assembly principle and the conditions under which they are performed, could be reused for semi automated production and later eventually even automated production.

Using a DFA strategy, manufacturing complexity will be disentangled into basic assembly operations. These operations can be performed by relatively s i m p l e manufacturing platforms. By placing a larger number these platforms in a grid, a flexible manufacturing solution can be realised. The universal assembly platforms are called Equiplets, compact and low-cost manufacturing platforms that can be reconfigured to a broad number of applications by adding product dependent tools. These tools are very similar like the tools that are used during R&D and for the manufacturing of pre-production series. In this way existing R&D equipment is gradually upgradable, in a true re-configurable sense, investments in equipment are reduced significantly.

Especially when more agile manufacturing strategies are needed in an environment in which dealing with change becomes the central point, Equiplets can offer truly reconfigurable manufacturing, adaptable in small discrete steps, accurately matched to actual market demand.

Benchmarking Equiplet production has shown reduced time to market and a smooth transition from R&D to Manufacturing. When higher production volumes are needed, more systems can be placed in parallel to meet the manufacturing demand.

Costs of product design changes in the later stage of industrialisation have been reduced due to the modular production in grids, which allows the final design freeze to be postponed as late as possible. The need for invested capital is also pushed backwards accordingly.

The agility of the grid is unmatched. Reconfiguring machines can be done at a low level, reconfiguration of the Equiplets slows down production only partially. Total production shutdown, standard consequence in case of dedicated production lines, is prevented.

Future research

Future research will address a cost model that can be used to estimate industrialisation cost of Equiplet-Grid manufacturing in comparison to dedicated and flexible manufacturing systems.

Secondly the contribution of modern (agent based) controller architectures will be investigated to see if self learning capabilities can further increase the ease of use of Grid Manufacturing with Equiplets, preferably in the most early R&D stage.

Figure 1 :

 1 Figure 1: Concurrent development and engineering of High Volume manufacturing processes during the late proof of concept phase. By upgrading well-chosen production technology from R&D to production, a significant time gain can be achieved in bringing new developments to the market.

Table 2 :

 2 Example of dynamic configuration of a manufacturing grid. Production is expanded to roughly fifty Equiplets in 18 months to meet manufacturing demand for three products.