Keywords: Fuel cell, Durability, Reliability, Diagnostic, Preventive maintenance

This paper deals with a pattern-recognition-based diagnosis approach, which aim is to estimate the Fuel Cell (FC) operating time, and consequently its remaining duration life. With the method proposed, both static and dynamic information extracted from the stack (i.e. polarization curve records and Electrochemical Impedance Spectroscopy (EIS) measurements) can be used. The complete diagnosis method consists of several steps. First, features are extracted from EIS measurements and polarization curves independently. This enables us to simplify the extracted information without losing relevant information, and to remove noise. For the polarization curves, an empiric model is exploited to ensure the feature extraction. For the impedance spectra, both expert knowledge and parametric modeling are used to extract features. In particular, a latent regression model is used to split automatically the imaginary part of the spectra into several segments that are approximated by polynomials. The next step of the method consists in selecting the most relevant features from the whole set of extracted features. This helps us to estimate the operating time, while adjusting the complexity of the model. The final step of the approach is a linear regression that uses the selected subset of features to estimate the FC operating time. The performances of the proposed approach are evaluated on a dataset made up of EIS measurements and polarization curves extracted from two FC lifetime tests. A mean error of about 2 hours over a global operating duration of 1000 hours can be obtained. Moreover, the portability of the method is shown by considering another FC ageing test conducted on a different FC stack type.

• R. Onanena, L. Oukhellou, D. Candusso, F. Harel, D. Hissel, P. Aknin. Fuel cells static and dynamic characterizations as tools for the estimation of their ageing time. Accepté dans International Journal of Hydrogen Energy le 22/10/2010. Ed. Elsevier.

Fuel cells static and dynamic characterizations as tools

Introduction

PEM Fuel Cells (FC) are electrochemical systems that convert directly hydrogen energy into electrical energy with high efficiency, and no CO 2 emission. That is why those systems appear as promising technology solutions, especially for transports. However, FCs still suffer from a low reliability and a short lifetime, which make them difficult to meet today's requirements. Indeed, a minimal lifetime of 5000 hours is required for stacks dedicated to vehicular applications [START_REF] Harel | PEMFC durability test under specific dynamic current solicitation linked to a vehicle road cycle[END_REF][START_REF] Wahdame | Comparison between two PEM fuel cell durability tests performed at constant current and under solicitations linked to transport mission profile[END_REF]. It is therefore important to accurately predict FC state-of-health and remaining duration time. For that purpose, it is necessary to develop diagnosis schemes that can evaluate FC state-of-health adequately, especially for maintenance purposes. Therefore, it is important to establish a link between the FC degradation phenomenon and the FC physical characterizations that can be employed throughout ageing time to estimate the FC lifetime, and consequently the remaining duration life during operations.

Previous studies have been conducted to evaluate FC stack performances through the time evolution of various parameters [START_REF] Ciureanu | Electrochemical Impedance Study of PEM Fuel Cells. Experimental Diagnostics and Modeling of Air Cathodes[END_REF][START_REF] Merida | Characterisation of proton exchange membrane fuel cell (PEMFC) failures via electrochemical impedance spectroscopy[END_REF][START_REF] Laffly | Polymer Electrolyte Membrane Fuel Cell Modelling and Parameters Estimation for Ageing Consideration[END_REF]; others have been done to estimate the FC operating time (respectively lifetime) by using Electrochemical Impedance Spectroscopy (EIS) measurements [START_REF] Lee | Development of a method to estimate the lifespan of PEM fuel cell using electrochemical impedance spectroscopy[END_REF].

In previous studies, we have used a pattern-recognition-based approach to estimate the FC operating time, using EIS measurements (dynamic characterizations) only [START_REF] Onanena | Estimation of fuel cell life time using latent variables in regression context[END_REF][START_REF] Onanena | Estimation of fuel cell operating time for predictive maintenance strategies[END_REF]. With this work, we obtained an estimation of the operating time with a mean square error on the test set of 95 hours over a total duration of 1000 hours. It seemed then interesting to investigate the possible improvement of the results, when using both dynamic and static characterizations. This paper focuses on this issue. Therefore, in the following, the same pattern-recognition-based approach is exploited on the same FCs that were used in [START_REF] Onanena | Estimation of fuel cell operating time for predictive maintenance strategies[END_REF], and both EIS measurements and polarization curves are considered (first separately, then combined) for the estimation of the operating time. In addition, the portability of the method is shown by considering another FC ageing test conducted on a different FC stack type.

The paper is organized as follows. In Section 2, the principle of the pattern-recognition-based approach will be presented. In Section 3, the two FC characterizations are detailed, especially their relevance regarding the estimation of the FC operating time. Feature extraction and selection methods are presented in Sections 4 and 5. The test procedure for the operating time estimation is given in Section 6. The performances of the proposed approach obtained on real datasets are summarized in Section 7.

Principle of the pattern-recognition-based approach

A pattern-recognition-based diagnosis aiming to estimate the FC operating time from both EIS measurements and polarization curves is here presented. The intrinsic aim is to exploit both static and dynamic information that are extracted from the stack to estimate the FC operating time, and consequently its remaining duration life. The complete diagnosis tool, presented in Fig. 1 consists of several steps. First, FC undergoes a characterization process: EIS measurements and polarization curves are performed. Then the second step is a feature extraction that consists in generating features from polarization curves and EIS measurement independently. This step aims at first summarizing efficiently the measurements without losing relevant information, and then at removing noise. For the polarization curves, two empiric models are employed for feature extraction. As for impedance spectra, various methods based on expert knowledge can be used to extract features [START_REF] Tsujioku | Analysis and modelling of a direct methanol fuel cell for failure diagnosis[END_REF][START_REF] Hissel | Fuzzy Clustering Durability Diagnosis of Polymer Electrolyte Fuel-Cells dedicated to transportation applications[END_REF]. Particular points (or hyperparameters) are first empirically extracted and tested. Then, two parametric modeling are performed on the real and the imaginary parts of the spectrum. In particular, a latent regression model is exploited to split automatically the imaginary part of the spectrum into several segments that correspond to different FC physical behaviors. The third step is feature selection. This step enables to select the most relevant features from the whole set of extracted features to estimate the operating time, while adjusting the complexity of the chosen model. Indeed, a tradeoff has to be made between complexity (i.e. the number of selected features) and accuracy in order to avoid the well-known phenomenon of overfitting [START_REF] Bellman | Adaptive Control Processes: A Guided Tour[END_REF][START_REF] Duda | Pattern classification[END_REF]. While an overly complex model could pass exactly through all the experimental points, it could also lead to a poor representation of the real phenomenon. However, the reverse situation of an overly simple model (less complexity) could also lead to a poor representation of the phenomenon. Furthermore, dimensionality reduction is also essential to avoid overfitting when the available training data set is small as it is in our case. The final step of this approach is a linear regression that uses the selected subset of features to estimate the FC operating time. In fact, this operating time is an equivalent period that corresponds to the elapsed time during which an identical FC operates under nominal conditions.

Fuel cell characterization

Durability tests were performed on two identical small power PEMFCs (three-cell stacks of about 100 W) during 1000 hours. These stacks have been assembled with graphite gas distributive plates, commercial membranes (Gore MESGA Primea MEA Series 5510; active cell area of 100 cm 2 ) and Gas Diffusion Layers (GDLs) [START_REF] Harel | PEMFC durability test under specific dynamic current solicitation linked to a vehicle road cycle[END_REF][START_REF] Wahdame | Comparison between two PEM fuel cell durability tests performed at constant current and under solicitations linked to transport mission profile[END_REF]. The first stack (FC1) was operated in nominal and stationary conditions. The load current was constant and equal to 50 A.

In the second test, the fuel cell (FC2) was operated under dynamical load current based on a real transportation mission profile (maximum current of 70 A was reached for an average of 12.5 A). For both stacks, the set of anode/cathode stoichiometry rates was fixed to 2/5. Details on the test conditions and kind of current solicitation can be found in [START_REF] Harel | PEMFC durability test under specific dynamic current solicitation linked to a vehicle road cycle[END_REF][START_REF] Wahdame | Comparison between two PEM fuel cell durability tests performed at constant current and under solicitations linked to transport mission profile[END_REF], as well as the complete characterization test results. During these ageing tests, the stacks were characterized regularly (twice per week) through polarization curves and impedance spectra.

Polarization curves

The polarization curve gives information about the static behavior of the FC. It is a powerful tool for various applications such as FC characterization, ageing studies, or diagnosis. In order to realize a polarization curve, one has to make sure that the operating conditions (temperatures, pressures, humidities…) are stable. Therefore, before every series of characterization, the FCs were operated under the same operating point for 30 minutes [START_REF] Harel | PEMFC durability test under specific dynamic current solicitation linked to a vehicle road cycle[END_REF][START_REF] Wahdame | Comparison between two PEM fuel cell durability tests performed at constant current and under solicitations linked to transport mission profile[END_REF].

In general, depending on the current density interval, polarization curves can reveal three different internal behaviors of the FC [START_REF] Barbir | Fuel cells: Theory and practice[END_REF][START_REF] Zhang | Estimation of contact resistance in proton membrane fuel cell[END_REF] (see Fig. 2). In low current densities, the curves illustrate charge transfer kinetics; in medium current densities, the slope and form of the polarization curves are highly influenced by ohmic resistance; and finally in high current densities, the influence of the mass transfer is highlighted.

As it can be seen in Fig. 2, both the form and the slope of polarization curves vary through time, during the ageing experiments. This leads us to believe that a parameterization of polarization curves can be helpful to provide suitable indicators relating to the ageing phenomenon in FCs.

Electrochemical Impedance Spectrum

Unlike the polarization curve, Electrochemical Impedance Spectroscopy (EIS) enables us to obtain relevant information about the dynamical behavior of the FCs during an ageing process [START_REF] Rubio | Diagnosis of performance degradation phenomena in PEM fuel cells[END_REF][START_REF] Yan | AC impedance characteristics of a 2 kW PEM fuel cell stack under different operating conditions and load changes[END_REF][START_REF] Didierjean | Forces et faiblesses de la pile à membrane échangeuse de protons[END_REF]. EIS allows the characterization of dynamic processes occurring at different timescales in the system. Considering this technique, the FC is placed on a static operating point and then additional small amplitude solicitation signals are applied. In our case, both stacks were placed under the operating point of 35A, and a small sinusoidal alternating part (with amplitude of 1 A and frequency range from 10 mHz to 30 kHz) was applied around it. Each recorded impedance spectrum was a series of impedance measurements at 45 discrete frequency points.

The different ageing test conditions applied on both stacks have led to different EIS results for each FC [START_REF] Harel | PEMFC durability test under specific dynamic current solicitation linked to a vehicle road cycle[END_REF][START_REF] Wahdame | Comparison between two PEM fuel cell durability tests performed at constant current and under solicitations linked to transport mission profile[END_REF]. As an example, the impedance plots measured during the ageing test conducted on FC1 stack are presented in Fig. 3. It can be observed that the FC impedance can be divided into three parts, each part corresponding to a distinct dynamic behavior:

a first capacitive arc (f < 130 Hz) due to mass and water transports, a second capacitive arc (130 Hz < f < 4 kHz) due to the charge (electrons and protons) transfer processes, an inductive part which is present in high frequencies (4 kHz < f) due to connections (internal and external ones). The delimiting frequency values presented above are approximate values, and they depend on the FC and its ageing state. Our goal is to use these characteristics, especially their evolution to estimate the FC operating time. Indeed, they seem to be good indicators of the ageing phenomenon in FCs. More details on physical processes behind these intervals can be found in [START_REF] Harel | PEMFC durability test under specific dynamic current solicitation linked to a vehicle road cycle[END_REF][START_REF] Wahdame | Comparison between two PEM fuel cell durability tests performed at constant current and under solicitations linked to transport mission profile[END_REF]. Fig. 3 -Presentation of hyperparameters in the impedance spectrum (left) and evolution of the impedance spectra for FC1 stack from the initial state (Time : 0 h) to the final state (Time: 995 h) (right).

Feature extraction

The goal of this processing phase is to generate automatically a subset of features that will represent the data. The underlying motivation is that the data can be represented in a subspace whose intrinsic dimensionality is lower than the one of the original data space [START_REF] Duda | Pattern classification[END_REF].

Feature extraction on the polarization curves

Feature extraction on a polarization curve consists in approximating it by external model and using afterwards the model parameters as features. Previous studies on FCs have underlined many empiric models of polarization curves [START_REF] Didierjean | Forces et faiblesses de la pile à membrane échangeuse de protons[END_REF]. The following model is investigated here:

( 1 )

Moreover, the experimental results have shown that the open circuit voltage (noted U 0 ) is linked to the ageing phenomenon (see Fig. 2). Therefore, the number of extracted parameters for the polarization is five (U 0 , α 1 , α 2 , α 3 , α 4 ). Figure 4 presents the behavior of the model obtained on a polarization curve modeling.

Fig. 4 -Example of an approximation of a polarization curve.

Feature extraction on the EIS

For the impedance spectra, two different methods were considered. The first one, based on expert knowledge, consists in the empirical extraction of particular hyperparameters from the spectrum. The second method on the other hand, consists in separating first the impedance spectrum into two curves that represent the evolution of the real and imaginary parts of the impedance as functions of the frequency, and then in approximating each one of them by an external model.

Extraction of hyperparameters

Previous studies presented in [START_REF] Tsujioku | Analysis and modelling of a direct methanol fuel cell for failure diagnosis[END_REF][START_REF] Hissel | Fuzzy Clustering Durability Diagnosis of Polymer Electrolyte Fuel-Cells dedicated to transportation applications[END_REF] have focused on identifying characteristic points in the impedance spectrum that can be employed to diagnose FC stacks. The following parameters were chosen as features:

the polarization resistance value, the minimal value of the imaginary part in the impedance spectrum, its corresponding real part values and its occurring frequency (3 hyperparameters in total), the internal resistance value and its corresponding frequency of occurrence (2 hyperparameters). Thus for each impedance spectrum, a set of 6 hyperparameters is extracted. In Fig. 3, the influence of the ageing process on the hyperparameters evolution can be observed.

Parametrization of the real and imaginary parts of the spectrum

With an explicit point of view, each EIS spectrum could be split into a real part and an imaginary part function of the frequency (see Fig. 5). An inherent link can be established between the FC ageing phenomenon and the evolution of these curves. Therefore, it seems interesting to extract features from these plots that can be used afterwards to estimate the ageing time of the FC stack.

Feature extraction on the real part of the impedance:

The real part of the impedance can be approximated by an external model of four parameters related to an extended "logsig" function and defined as follows:

(

The four model coefficients are determined by minimizing a cost function based on a mean square error with the help of simplex method [START_REF] Duda | Pattern classification[END_REF].

Feature extraction on the imaginary part of the impedance:

Rather than using a global fitting of the imaginary part of the spectrum, the idea that we investigate is to automatically partition it into different segments that can be approximated individually by a polynomial. The number of segments is chosen in relation with the physical behavior of the FC stacks while their location and polynomial coefficients are determined by a probabilistic-model-based approach. Further details can be found in [START_REF] Onanena | Estimation of fuel cell life time using latent variables in regression context[END_REF][START_REF] Onanena | Estimation of fuel cell operating time for predictive maintenance strategies[END_REF][START_REF] Chamroukhi | Time series modeling by a regression approach based on a latent process[END_REF]. But the following summarizes this approach. This feature extraction is made up of a specific regression model that incorporates 3 polynomial regimes (see Section 3.2), and the switching from one regime to another is controlled by a latent variable z i . More formally, if is the n points of imaginary part of an impedance spectrum obtained for the frequencies (f 1 ,..., f n ) (f i will denote the logarithm of the frequency), then the model can be written as: [START_REF] Ciureanu | Electrochemical Impedance Study of PEM Fuel Cells. Experimental Diagnostics and Modeling of Air Cathodes[END_REF] Where:

is a discrete variable representing the class label of the polynomial regression mode (K=3), is the regressor vector associated with , is the variance coefficient associated with .

From this equation, it can be proven that each variable x i is distributed according to a mixture density:

Where: is the logistic transformation of the frequency , such that:

(5) and is the parameter vector of the logistic process.

The model parameters to be estimated are ), where is the vector of coefficients of the polynomial approximating segment i. In order to estimate these parameters, the likelihood function of is maximized with a dedicated EM (Expectation-Maximization) algorithm [START_REF] Mclachlan | Finite mixture models, Wiley series in probability and statistics[END_REF][START_REF] Dempster | Maximum likelihood for incomplete data via the EM algorithm[END_REF]. In addition, the parameters of the hidden logistic process, in the inner loop of the EM algorithm, are estimated using a multi-class Iterative Re-weighted Least-Squares (IRLS) [START_REF] Green | Iteratively Reweighted Least Squares for Maximum Likelihood Estimation, and some robust and resistant alternatives[END_REF]. Figure 6 illustrates the behavior of the modeling where the three domains are clearly identified.

Feature selection

The aim of feature selection is to choose a subset of relevant features from the previously extracted ones that retain most of the information about the FC ageing and simultaneously suppress the main part of the "inevitable" model noise. This step is an important part of the approach because it enables us not only avoiding overfitting and noise disturbance, but it can also reduce computation time of the operating time estimation. That is why different methods were carefully explored, in order to get the best possible results.

To find the optimal subset of features would require computing an exhaustive search, i.e. an evaluation of all the possible subsets of features by training its associate regressor, and then selecting the subset that provides the best performance in terms of operating time estimation. However, given the fact that the number of extracted features is relatively high when both EIS measurements and polarization curves are considered, an exhaustive search would lead to too high computational costs. In order to guarantee the best possible result despite the use of a nonoptimal feature selection method, three different suboptimal feature selection methods were considered in addition to the exhaustive search:

the Sequential Forward feature Selection (SFS) starts with an empty feature set (E 0 = ∅ (empty set)), adds one feature at a time (X i ), and at each stage chooses the feature whose addition gives the best performances in terms of the performance criterion J [START_REF] Fukunaga | Introduction to Statistical Pattern Recognition[END_REF].

Begin {

Initialization:

E 0 = ∅ (empty set), E = { X i , i = 1 ... D } for each step k = 1 ... D: -evaluate J{ E k-1 ∪ X i } for all X i ∈{ E-E k-1 } find J(E k ) = min J{ E k-1 ∪ X i } return E k = { E k-1 ∪ X i / J(E k ) } end }
the Sequential Backward feature Selection (SBS) procedure starts with the entire feature set (E 0 = E (full set)) and at each step k drops the feature whose absence less penalizes the criterion J [START_REF] Fukunaga | Introduction to Statistical Pattern Recognition[END_REF].

Begin {

Initialization: E 0 = E (full set), E = { X i , i = 1 ... D } for each step k = 1 ... D:

-evaluate J{ E k-1 -X i } for all X i ∈{ E k-1 } find J(E k ) = min J{ E k -X i } return E k = { E k-1 -X i / J(E k ) } end }
the Adaptive Branch and Bound (ABB): the ABB developed by S. Nakariyakul [START_REF] Nakariyakul | Adaptive branch and bound for selecting optimal features[END_REF]25], is an improvement of the basic branch and bound (BB) algorithm by P. Narendra and K. Fukunaga [START_REF] Fukunaga | Introduction to Statistical Pattern Recognition[END_REF]. Considering the selection of d features from an initial set of D, the BB-type algorithms look for the subset of features by partially scanning the "solution" tree from top to bottom with the possibility of backtracking. Each node of the tree corresponds to a discarded feature. Compared with the basic BB algorithm, the improvements are: (1) the ordering of the tree nodes by significance of the features during the construction of the tree, (2) the selection of the initial bound by a floating search method, (3) a starting search level other than the top of the tree, and (4) the introduction of an adaptive jump search that selects search levels and avoids redundant calculations. More details can be found in [START_REF] Nakariyakul | Adaptive branch and bound for selecting optimal features[END_REF]25]. [1,...,D]. , and go to step 5 end }

The basic BB algorithm zi: variable's index, that takes values in

Begin

Test procedure for the operating time estimation

The final step of this estimation phase is the evaluation of the performances of the linear regression model. A cross validation is used. Because of the small size of the data (29 impedance spectra and 29 polarization curves), a particular cross-validation technique, known as the "leave-one-out" technique is carried out as follows [START_REF] Bellman | Adaptive Control Processes: A Guided Tour[END_REF][START_REF] Bishop | Pattern recognition and machine learning[END_REF]. Consider the data made up of N elements. The model is trained using (N-1) elements (the training set), and tested on the N th element (the test set). The process is repeated until each of the N elements is used as a test set. The error rate is then estimated by computing the average of the N resulting test errors. This computation of the error rate will give us an estimation of how well the regression will perform on a new data. In the case of a linear regression, the mean square error as the error rate is used.

The "leave-one-out" technique is generally expensive in time computation but it must be used in our case because the data set is very limited. A simple linear regression is achieved for the operating time estimation

Results

With the following experiments, the capability of the proposed approach to estimate the operating time using the extracted features can be illustrated. The performances are evaluated on a real dataset made up of 29 impedance spectrum measurements and 29 polarization curves carried out on two FCs (FC1 and FC2 as previously described in Section 3) during 1000 hours of operation time. The feature extraction methods detailed above were applied on the impedance spectra and the polarization curves. These lead to the extraction of variables:

-6 hyperparameters: the internal resistance (h 1 ), the polarization resistance (h 2 ), the minimal value of the imaginary part of the spectrum (h 3 ) and its corresponding real part (h 4 ), and the respective frequencies corresponding to the internal resistance (h 5 ), and the peak of the spectrum (h 6 ), -4 features from the real parts: {a i } 1≤i≤4 , -14 parameters from the imaginary parts: {β i,j , f 1 , f 2 } 1≤i,j≤4 (3 hidden logistic process regressions with 12 coefficients of the three-order polynomial fitting of the curve and the 2 frequencies delimiting the central polynomial), -5 parameters from the polarization curve model {U 0 , α 1 , α 2 , α 3 , α 4 }. The total number of initial extracted features is therefore 29. The next step of the procedure goes as follows. First, the estimation of the FC operating time is done using EIS spectra and polarization curves separately and while applying each feature selection method. Then, the two sources of information are combined (EIS spectra and polarization curves) and likewise, the estimation is done while applying each feature selection method. These different evaluations are performed in order to highlight the relevance of combining the information extracted from both EIS measurements and polarization curves. The parameter combinations are evaluated in terms of the mean square error of the operating time. At the end of each learning phase, the chosen combination is the one that leads to the minimal rate of the mean square error on the test set.

Results of the estimation of the FC operating time when using ABB as feature selection method

The use of the ABB algorithm for the feature selection has led to the selection of a subset of 24 parameters to estimate the operating time. These parameters correspond to all the parameters except β 11 (the constant value in the first polynomial of the impedance imaginary part, in low frequencies), β 24 (the value affected to the cubic term of the second polynomial of the impedance imaginary part, in medium frequencies), a 3 (of the impedance real part), U 0 (the FC voltage for a zero load current), and α 3 (the quadratic term of the polarization curve model). Figure 7 illustrates the distribution of Mean Square Error (MSE) over all the operating time estimation among the database versus the number of selected parameters. In order to see more clearly the evolution of the MSE, a zoom has been performed (leaving the results obtained for a number of selected features of 28 and 29 out of the figure, because the resulting MSEs in these cases are far higher than otherwise). On this figure, one can observe that the operating time of the FC can be estimated with a mean square error of 2 hours over the total duration of 1000 hours. Moreover, we can see that two spikes appear on the test error curve. In most problems, the test error typically decreases then increases, thus a minimal test error appears. This minimal error is used as an indication that from that point when increasing the complexity, the chosen model may be overfitting the data [START_REF] Duda | Pattern classification[END_REF]. However, the modeling of the noise could make appear spikes on the test data, as shown in Fig. 7 (for the numbers of selected features equal to 17 and 20).

The other results

Table 1 presents the results obtained on the whole dataset for the different feature selection methods that were exploited, and Table 2, the number selected features per selection method. In Table 1, in each feature selection method, there are two sub-columns, presenting the results for the training set and the test set respectively. Overall, it can be seen that the training error decreases when the number of selected parameters for the estimating model increases (see Fig. 8). This shows that the more complex the model is, the more it tends to learn correctly the data. Hence, the lower the training error is. However, an overly complex model for the regression could model the noise, and therefore poorly perform on the test set. This is why the test error decreases first and then increases. The point, which corresponds to the minimal test error, gives a trade-off between accuracy and complexity. Moreover, one can observe that for the polarization curves only (i.e. for a small number of initial features), all the 4 feature selection methods give the same (optimal) results. For larger numbers of features, the best results are obtained with the branch and bound algorithm. But these results remain suboptimal: indeed the results obtained by the ABB algorithm are not as good as the ones obtained with the exhaustive search (see results for the estimation using EIS spectra only in Fig. 8). Given these observations, one can conclude that despite their suboptimality, the feature selection methods that were used (SFS, SBS, and ABB) have given results that are close to the optimal ones, in the cases of larger initial feature sets. Moreover, it can be noted that it is the combination of features extracted from both the polarization curves and the impedance spectra that gives very good results, even though the number of selected features in that case is high. As one can see in Table 1 and Fig. 8, the results obtained with features from impedance spectra and polarization curves separately are not as good the previously presented results. One can therefore conclude that better results are obtained by combining both the static and dynamic characterizations (i.e. both the polarization curves and the impedance spectra): with this combination of static and dynamic information, the estimation of the operating time (respectively of the ageing time) can be done with a mean error of 2.4 hours on the test set.

Portability of the method

In order to investigate the feasibility of the approach presented here on other FC types, the methodology was applied on a smaller dataset extracted from a different PEMFC type [START_REF] Wahdame | Impact of power converter current ripple on the durability of a fuel cell stack[END_REF]. This FC (noted here FC3) is five cell stack of 600 W assembled with graphite gas plates, commercial membranes and GDLs. It was operated during 1000 hours under nominal conditions, with the load current constant and equal to 250 A. The polarization curves were recorded in a similar way to FC1 and FC2. For the EIS measurements, the FC polarization point was set to 150 A, and a small sinusoidal alternating part (with amplitude of +/-25 A and frequency range from 10 mHz to 30 kHz) was applied around it [START_REF] Wahdame | Impact of power converter current ripple on the durability of a fuel cell stack[END_REF]. These characterizations enabled us to produce a data set of 8 spectra and 8 polarization curves. The same methodology was then applied to this dataset. Table 3 presents the results obtained on the whole dataset for the different feature selection methods that were exploited, and Table 4, the number of selected features per selection method. These results show that the pattern-recognition-based approach could be applied on another type of FC. Interesting results are obtained. Indeed, with this data, we also have an estimation of the operating time with a mean error less than 3 hours.

Conclusion

A method to estimate the operating time of FCs, using a pattern-recognition-based approach on both EIS measurements and polarization curves, has been presented in this article. In a previous paper, the same approach was exploited using only EIS measurements. The idea that was investigated here is the possibility of improving the operating time estimation when both EIS measurements (dynamic characterizations) and polarization curves (static characterizations) are exploited. This involves two methods for feature extraction from the impedance spectra, the using of an empiric model for feature extraction on polarization curves, a feature selection procedure to keep only relevant descriptors and a regression model. Because of the size of the set of extracted features, different suboptimal feature selection methods were exploited to ensure that the obtained results were as close to the optimal solutions as possible. Evaluations on real data set have shown that FC operating time (respectively remaining lifetime) can be estimated with a mean error as low as 2 hours over a global operating duration of 1000 hours. This shows an improvement of the results, compared with those obtained previously with EIS measurements only (a mean error of 95 hours over a global operating duration of 1000 hours), and despite the use of suboptimal methods for feature selection.. Moreover, the results we have obtained when using another type of FC show a possible applicability of the method on various

  for the estimation of their ageing time R. Onanena a,b,c , L. Oukhellou c,d,* , D. Candusso a,c,* , F. Harel a,c , D. Hissel a,b , P. Aknin c a FC LAB, Techn'Hom, rue Thierry Mieg, 90010 Belfort Cedex, France b FEMTO-ST (UMR CNRS 6174), ENISYS Department, University of Franche-Comté, France c INRETS, "Le Descartes 2", 2 rue de la butte verte, 93166 Noisy-le-Grand Cedex, France d CERTES Université Paris 12, 61 avenue du Gal. De Gaulle, 94100 Créteil, France

Fig. 1 -

 1 Fig. 1 -The pattern-recognition-based diagnosis applied on FCs diagnosis.

Fig. 2 -

 2 Fig. 2 -Presentation of the three parts of the polarization curve (left) and evolution of the polarization curves for FC1 stack from the initial state (Time : 0 h) to the final state (Time : 995 h) (right).

Fig. 5 -

 5 Fig. 5 -Evolution of the real and imaginary parts of the impedance spectrum versus frequency for FC1 from the initial state (Time : 0) to the final state (Time : 995 h).

Fig. 6 -

 6 Fig. 6 -Original signal, the three polynomials (top), and their corresponding logistic probabilities (bottom) for the parameterization of EIS imaginary part.

Fig. 7 -

 7 Fig. 7 -Operating time estimation over the training and the test sets for the linear regression when using the ABB algorithm for feature selection.

Fig. 8 -

 8 Fig. 8 -Operating time estimation over the training and the test sets for the linear regression when using respectively the exhaustive search on spectra only (a)), the ABB algorithm on spectra only (b)), and the ABB algorithm on polarization curves only (c)).

Table 1 -

 1 Model estimation of the FC operating time (in hours) using different input descriptors and different feature selection methods.

	Feature selection	Exhaustive	SFS		SBS		ABB
	method	search
		Training	Test	Training	Test	Training	Test	Training	Test
		set	set	set	set	set	set	set	set
	Polarization curves	131.5	144.1	131.5	144.1	131.5	144.1	131.5	144.1
	EIS spectra	51.3	95.0	81.39	152.68	76.6	106.9	68.8	103.8
	EIS polarization curves spectra +	--	--	101.3	125.7	7.8E-12	29.9	8.9E-10	2.4

Table 2 -

 2 Presentation of the number of selected features per selection method.

	Feature selection	Exhaustive	SFS	SBS	ABB
	method	search
	Polarization curves	2	2	2	2
	EIS spectra	13	12	8	9
	EIS spectra + polarization curves	--	6	25	24

Table 3 -

 3 Model estimation of the operating time (in hours) using different input descriptors and different feature selection methods applied on FC3.

	Feature selection		SFS		SBS		ABB
		method
				Training	Test	Training	Test	Training	Test
				set	set	set	set	set	set
	Polarization curves		61.34	187.6	65.18	136.9	65.18	136.9
	EIS spectra		9.9	42.67 3.74E-13 40.04	1.7E-12	3.28
	EIS	spectra	+	1.38E-12	2.68	1.36	12.9	1.38E-12 2.68
	polarization curves

Table 4 -

 4 Presentation of the number of selected features per selection method.

	Feature selection	SFS	SBS	ABB
	method
	Polarization curves	4	2	2
	EIS spectra	5	12	9
	EIS spectra +	6	20	6
	polarization curves

types of FC stacks. Nevertheless, this will have to be validated on more data. These results could lead to interesting perspectives, particularly in preventive maintenance context.

9.


Christian Bourret
email: bourret@univ-mlv.fr

Eguzki Urteaga
email: eguzki.urteaga@ehu.es

New "pays" (little countries) as local level of the process of Territorial Intelligence in France. Comparative study of the Pays Basque and the Couserans

Keywords: neighbouring territory, territorial intelligence, project, network, representations, identity pays, intelligence territoriale, projet, réseau, représentations, identité país, inteligencia territorial, proyecto, red, representaciones, identidad

The laws of 1995 and 1999 on planning and development of territory, extended in 2003, allowed the assertion of the "pays" (local countries) which constitute territories having a geographical, cultural, economic and social cohesion carrying joint projects (territories of projects). They met certain success. On January 1 st , 2007 France counted 334 recognized "pays". The "pays" are in the heart of the policies of sustainable development of the territory. However, this common denomination hides realities very different, so much on the level of the political situations, cultural, economic and social and on the level of the projects of territory which approach varied fields. They have different competences, various resources and very different budgets. The examples of the Pays Basque in Aquitaine and Couserans in the Midi-Pyrénées region offer significant illustration. These two examples are used to analyze the "pays" within a process of Proximity Territorial Intelligence centred on the identity, the construction of the convergence of the actors' representations, the social networks, the projects culture within the framework of the new uses of ICT and the economy of the immaterial.

Résumé

Les lois de 1995 et 1999 sur l'aménagement et le développement du territoire, étendues en 2003, ont permis l'apparition des « pays » qui constituent des territoires présentant une cohésion géographique, culturelle, économique et sociale tout en étant porteurs de projets communs (territoires de projets). Ils ont connu un certain succès puisqu'au 1 er janvier 2007 la France comptait 334 « pays » reconnus. Les « pays » se trouvent désormais au coeur des démarches d'aménagement et de développement durable du territoire. Pourtant, cette dénomination commune cache des réalités très différentes, tant au niveau des situations politiques, culturelles, économiques et sociales qu'au niveau des projets de territoire qui abordent des domaines variés, disposent de compétences, de ressources très différentes et de budgets qui n'ont pas de commune mesure les uns avec les autres. Les exemples du Pays Basque en Aquitaine et du Couserans en Midi-Pyrénées en offrent une parfaite illustration. Ces deux exemples nous servent à situer les pays au sein d'un processus d'Intelligence Territoriale de proximité centrée sur l'identité, la construction de la convergence des représentations des acteurs, les réseaux sociaux, les cultures à projet dans le cadre des nouveaux usages des TIC et de l'économie de l'immatériel.

Resumen

Las leyes de 1995 y 1999 sobre la ordenación y el desarrollo territorial, extendidas en 2003, han propiciado la aparición de los "países" que constituyen territorios de proximidad que presentan una cohesión geográfica, cultural, económica y social además de compartir proyectos (territorios de proyectos). Han conocido un cierto éxito puesto que, el 1 de enero de 2007, Francia contaba con 334 "países" reconocidos. Los "países" se encuentran de ahora en adelante en el centro de las iniciativas de ordenación y de desarrollo sostenible del territorio. No obstante, este denominación común esconde realidades muy diferentes, tanto al nivel de las situaciones políticas, culturales, económicas y sociales como al nivel de los proyectos de territorio que abordan distintos ámbitos, disponen de competencias y de instrumentos diversos y se benefician de presupuestos que no tienen nada que ver los unos con las otros. Los ejemplos del País Vasco en Aquitania y del Couserans en Midi-Pyrénées ofrecen una perfecta ilustración de ello. Estos dos ejemplos nos sirven para situar los "países" en el seno de un proceso de Inteligencia Territorial de proximidad centrada en la identidad, la construcción de la convergencia de las representaciones de los actores, las redes sociales, las culturas de proyecto en el marco de los nuevos

INTRODUCTION

Territorial Intelligence develops gradually in France, in particular following the key points of Carayon's report about Economic Intelligence, competitiveness and social cohesion (2003) which highlighted the importance of the regional level. Significantly, in 2006, the DATAR (Délégation pour l'Aménagement du Territoire et l'Action Régionale), created in 1963 at the time of voluntarism of general de Gaulle's government, became the DIACT (Délégation Interministérielle à l'Aménagement et à la Compétitivité des Territoires). The laws of 1995,1999 and 2003 defined a new local framework of country planning: that of the "pays" (local countries). In this paper, we propose to study the assertion of this new level of proximity then to illustrate its diversity by the comparative study of the Pays Basque (Aquitaine) and Couserans (Midi-Pyrénées). We wonder about the future of these "pays" before analyzing the way in which they can constitute the local level of a regionalized process of Territorial Intelligence.

1.

A NEW TERRITORIAL LEVEL OF PROXIMITY

The assertion of a new territorial level

As soon as the 1970s, contracts of country development were concluded between the regional level and proximity territories of variable size, especially in the West of France. Then, during the following decade, tourist countries were constituted to develop the tourist economy and to organize the offer and the promotion. The law of February 4th, 1995 of orientation for the development of territory (LOADT), known as law Pasqua, considers the "pays" as "an organization of the territory based on the concepts of basins of life, organized in specific territory, and of networks of cities". The law does not impose any obligation of legal structuring of the territory to respect the diversity of the local forms of cooperation. Nearly 120 initiatives of "pays" existed in 1999.

The law of June 25th, 1999 of orientation for the sustainable development of territory (LOADDT), known as law Voynet, constitutes a determining step in the organization of the "pays" as territories of projects. It reaffirms the "pays" by redefining its scale (that of the basin of employment), by pointing out its role of reinforcement of solidarity between cities and rural areas and by specifying the goals and the methods of development of its "joint project of sustainable development" which must be formalized in a charter. In order to organize the participation of the actors, it envisages the creation of the Council of Development with representatives of the economic, social, cultural and associative levels. In spite of the late publication of the decree about "pays" (in September 2000), the law Voynet starts again the dynamics of creation of the "pays" which had been blown after 1995.

After the legislative elections of 2002 and the change of parliamentary majority, the policy of the "pays" knows a certain undulation. We must wait until the law of July 2nd, 2003, about Urbanism and Housing operating a synthesis between the law Pasqua and the law Voynet for a revival of the policy of the "pays" with a procedure of simplified constitution.

The "pays" defined in 2003 is a local territory having a cohesion geographical, cultural, economic or social on a basin scale of life. It expresses the community of economic interests, cultural and social of its members. It constitutes the framework of the development of a joint project of sustainable development intended to develop the assets of a territory and to reinforce reciprocal solidarity between urban and rural spaces. It does not have vocation to constitute a specific administrative level but is an actor for dialog with the municipalities and the groups of municipalities (communautés de communes) which compose it. The programs carried by the "pays" have different goals linked with sustainable development with other administrative levels (European Union, National State, Region, Department) and can be implemented within the framework of multiannual contracts.

A rebirth of a strongly identity territory

Actually the development of the "pays" corresponds to a rebirth. The word corresponds, before 1789, at the zone of life of a rural population. At the beginnings of the French Revolution, in 1790, the representatives, who wanted to break the politico-administrative organization of the Ancien Régime, deleted its territorial frameworks (provinces, communities of valleys, etc.) to create new ones in a levelling point of view (abolishment of specificities or privilèges and imposition of the same law and legal competences on all the national territory) in dividing the national territory in new administrative frameworks : communes or municipalities (36 000) and départments (83 on all the national territory). The concept of "pays" then takes an other meaning: a national one, becoming the territorial framework of the sovereignty of the Nation-State which had gradually developed since the XIII th century. With the wars of the Revolution and the First Empire, the "fatherland" is the territory of sovereignty of the Nation-State with a strong policy about linguistic unification (French language against regional ones). At the end of the XIX th century, the word "pays" meets again a local meaning, in particular through works of geographers like P. Vidal de la Blache. So the rebirth of the "pays" can be regarded as a revenge of the history and geography on the administrative egalitarianism of the political Jacobinism.

AN EXTREME DIVERSITY ILLUSTRATED BY THE CASE OF THE PAYS BASQUE AND THE COUSERANS

On January 1 st , 2007, France counted 334 recognized "pays". But they are very different. Their diversity is illustrated by the case of Pays Basque and Couserans.

The French Pays Basque

The Pays Basque was recognized as "pays" in January 1997. It covers 2995 km ². The employment level is better than in other French areas, because of a demographic and economic dynamism. Its growth in population (+10,8% between 1982 and 1999) is due to migratory balance. The creation of new companies illustrates the economic development: rates of creation of companies are higher at the Pays Basque than in the Hexagon: 55 companies created for 10 000 inhabitants in Pays Basque against 45 companies created in France between 2001 and 2004. Consequently, 13 500 jobs were created between 1994 and 2004. The companies of the service sector are majority (63%). The 2/3 are located on the littoral zone where the population and the infrastructures concentrate. They are above all small units, the companies of more than 100 employees are few: 102 out of 26 400. In the field of higher education, the Pays Basque counted 4506 students in 2003, including 2445 at the University of Pau and the Countries of Adour (UPPA). This territory is characterized by the dynamism of its culture. The 1990s corresponded to two major tendencies: the assertion of the Basque cultural expression in the local cultural landscape and the taking into account of the cultural fact as factor of development. That in particular resulted in the constitution of an intercommunity association of support for the Basque culture and the installation of many cultural operators. The Basque identity rests largely on a very specific language, which is not an indo-european one, unlike French or Castilian. The situation is contrasted enough. The increase in the number of children provided education in bilingual teaching do not balance the loss generated by the decline of the family transmission. However, the Basque language is very strong in the audio-visual media, public education, especially in the primary and secondary education, the public and associative spaces, through the information panels near the roads and that of public services and companies.

The Pays Basque is characterized by its strong local identity and the revival of political claims. Since 40 years, the nationalist parties became the third political one with 15% of the votes, which enables them to have representatives in the municipal councils and playing a part of referee in second turns of elections. The claims of creation of a department Pays Basque, of a University of full exercise or development of bilingual teaching became a majority in the population. The Pays Basque is also characterized by its frontier situation which favours the exchanges and the cooperation between French and Spanish sides, cooperation resting on a common mentality and linked story. The will of the local actors to create a European metropolis (project of Eurocité Bayonne-San Sebastian) and, beyond, a Basque Euroregion implies to build a common project based on a shared history and a shared identity.

The "Pays" of Couserans

The "pays" of Couserans counts 27.980 inhabitants divided in 95 municipalities and 7 "cantons", on a surface of 1.639 km ². Couserans corresponds to the basin of river Salat (tributary of the Garonne) with the convergence of 18 valleys (which constitute specific identity territories) on two towns distant of 2 km: Saint-Lizier, capital of the Gallo-Roman city and bishopric until 1790, and Saint-Girons, seat of a viscounty, then sub-prefecture, important economic and trade centre.

The "pays" of Couserans was recognized in April 2002 and a contract of "pays" was firmed in January 2004. It is coordinated by an association (syndicat de pays) with an executive team of 10 permanent employees. There exists a Council of Development. The diagnosis of territory carried out for the project of Regional Natural Park (PNR) of the Pyrénées Ariégeoises. Its area, larger than that of "pays" of Couserans is centred on Couserans. It covers 2468 km ² and concerns 42 000 inhabitants. The diagnosis of the territory (2006) insists on the assets: an exceptional natural heritage with the presence of emblematic species (isards or Pyrenean bouquetin), water quality of the rivers, quality of the life. With also an interesting cultural heritage (churches particularly roman, castles), the specificity of the ancestral relations with near Spain, and an industrial inheritance (mines).

The main economic activities are the building (23%), the trade (22%), the activities of manufacture (18%), the hotels and restaurants (10%), the services to companies (9%), agriculture and wood (5%), the services to population (5%) and transport (3%).

If there exists since ten years a certain stability of the population, the ageing and the depopulation of the mountain areas near the frontier zone are very alarming. Unemployment rate is higher than the levels national and regional. The weakness of the financial means is shouting. Couserans is the poorest district of Ariège, department which counts the strongest proportion of recipients of the RMI (revenu minimum d'insertion). The rate of non-taxable families is roughly 60% (49% in average in France). In spite of the efforts of many associations, are also underlined the weakening of the local culture, the difficulties of communication and in particular the absence of connection towards Spain, public services with uncertain future, conservatism, even sectarianism against non natives inhabitants, the need "for injecting elixir of will to them"; without omitting the problems of disagreement between the municipalities and the self-centredness. In housing, the second home (residences secondaires) accounts for 39% of the dwellings of this territory project and more still in mountainous area.

The positive aspects are the strong mountain identity and the relations between the generations, strong community life, sport, social or cultural field, which can make it possible to maintain or develop services, the proximity of Toulouse and Spain as well as the strong potential in terms of formation-teaching: 64 schools, 4 colleges, 1 lycée, 2 LEP, 1 university centre in Foix specialized in tourism and rural development. The diagnosis also insists on fears: on change and about the uncertainties of the future with the risk of reinforcement of territorial oppositions and the exclusion of most fragile people.

Common points

Pays Basque and Couserans constitute frontier zones with Spain. The two "pays" corresponded to areas of dissidence, in particular with smuggling. But the evolution was very different. In Couserans, with the depopulation of the high valleys, accentuated by the arrival of the railroad, the mountain became a hard barrier with Spanish Catalonia whereas Bidassoa, if it marks the limits of the national territories, does not separate from an economic point of view and daily relations the two Pays Basque (Spanish and French). In a similar way, the two areas enjoy a strong collective identity (cultural and linguistic). But in Couserans, the Gascon (dialect of the Ooccitan) is hardly spoken by elder people while the French Pays Basque continues to speak the Basque, although to a lesser extent that in the close Basque autonomous Community.

Many differences

The comparison of the Pays Basque and Couserans illustrates especially the very important heterogeneity of the 334 countries. Indeed, there is few in common between a Pays Basque, strong of its 260 000 inhabitants, in full economic dynamism and which should be a department if French representatives of 1790 had not been opposed, and Couserans and its 27 000 inhabitants. If the district of Bayonne counted 114 000 inhabitants in 1901 and that of Saint-Girons counted 83 000 in 1880 ( 95 On the other hand, apart from the project of regional natural park which exceeds the area of the "pays", Couserans does not have a federative project. In the past, Couserans lacked many appointments: the railway tunnel of Salau towards Spain at the end of the XIX century, the thermal baths of Audinac in the years 1945-1950, a service of the National Library in Saint-Lizier in 1980-1981, and, always in 1980-1981, a project of National Park.

In the framework of the dynamics of the networks of health with the law of 2002, Echo-Santé is network of health dedicated to the elderly who gathers within an association, with cooperation public-private, located in the hospital of Saint-Girons, with the role of general doctors and liberal nurses. The buildings of the old hospital become thus a gathering centre of associations of service to the person like the network of health Echo-Santé or the association of assistance to home (ACMAD). Seeking to give more legibility to its actions and to support the cooperations between the territorial actors, the syndicat de pays de Couserans, after the diffusion of a newspaper, booklets, logically came to a project of Internet site. The ICT can constitute (Bertacchini, Dumas) a lever of territorial development which supports the construction of the territorial capital. This meeting of the territory of proximity and the ICT concerns the economy of immaterial (Levy-Jouyet, 2007). But Couserans is far from the interactions and the collaborative exchanges which make the force of the Pays Basque or areas like Sophia-Antipolis. The construction of the territorial immaterial capital is there only at its beginnings.

WHICH FUTURE FOR THE "PAYS"?

3.1. A limited success "Pays" do not cover all the national territory (only 73%). They are numerous in the North-Western quarter of France (Poitou-Charentes, Basse-Normandie, Brittany, Picardy, Nord-Pas-de-Calais and Pays-de-la-Loire) but do not exist in the Paris basin. They are above all rural territories gathering only 41% of the national population.

The "pays" must also face the strong competition of the communities of municipalities and the federative initiatives which come from them (SIVOM). The communities of municipalities born in February 1992, that is to say three years before the law Pasqua which correspond to the official rebirth of the "pays", in the prolongation of the laws of decentralization of 1982.

The defenders of the "pays" insist on the contrary on their complementarities, presenting the "pays" as a federation of communities of municipalities, which is the case in Couserans. We must also wonder about the too great diversity of the territorial levels in France: municipalities, "cantons", "pays", "arrondissements", departments, regions.

A too strong heterogeneity? …

A "pays" counts on average 79 municipalities and 74 300 inhabitants. The differences are very important: number of municipalities, inhabitants concerned and covered surface. The "pays" less populated, Vésubie (close to Nice), account 5103 inhabitants, whereas the population of the "pays" of Rennes (Brittany) is of 419.559 inhabitants. There also exist important disparities in terms of policy, economic, demographic and cultural situations, as in the Pays Basque and Couserans cases.

The reaffirmation of the "pays" also concern Spain and in particular Spanish Catalonia. In 1987, Generalitat made of the 41 "comarques" the basic cells of its provincial administration. Their heterogeneity is even stronger than in France: Barcelonès is at the same time the more populated "comarca" (2 216 000 inhabitants) and the smallest (145 km ²). The less populated "comarca" is the Alta Ribagorza, around Pont of Suert (4431 inhabitants for 427 km ²), and the largest Noguera, around Balaguer (1784 km² with 37 565 inhabitants).

… or a privileged framework of an identity of proximity?

In a world in full upheaval, with European construction, the opening of the borders, the globalization of the exchanges, the increasing mobility of the people, the acceleration of time and the diffusion of information thanks to ICT, the people search for reference marks and belonging to a community. The local territory answers this anguish and this search for meaning. The "pays" constitute strong identity markers. They are the land of the ancestors, the place where much of "exiled" come during the holidays and where they will return to finish their days when retired. The emotional attachment can even grow with the distance. The Basque identity remains very strong, even if it must integrate newcomers more and more. The Gascon identity of Couserans, although it is more difficult to materialize within a precise geographical framework, is also marked. The evolutions different from the Pays Basque and Couserans show nevertheless that if the identity constitutes an important asset, a necessary condition for the development, it is far from being sufficient.

THE LOCAL LEVEL OF A REGIONALIZED PROCESS OF TERRITORIAL INTELLIGENCE?

4.1.

Territorial Intelligence within a regional framework The Carayon report (2003) showed the importance of policies of Economic Intelligence within a territorial framework (the region level) to ensure competitiveness of companies and social cohesion. These stakes join those of the economy of immaterial (Levy-Jouyet) and of sustainable development in a context of proximity and territorial networks.

Territory construction by the convergence of the concepts of projects and networks accelerated by new uses of the ICT

We share the assumption of B. [START_REF] Pecqueur | Economie de proximités[END_REF]. According to them "the territory must be regarded as construction, a result of the practices and representations of the agents". G. Colletis and M. Salles work in particular on the stakes of the convergence of the representations in Midi-Pyrénées region. The concern is increasing the interactions between all the actors of the territory, to learn how to appreciate themselves for better working together for the construction of collective intelligence of the territory, the "pays" constituting a possible privileged territorial level for these goals. The ICT can be used as lever for the meeting of the identity and economic development by creating the conditions of the development of a formal territorial capital. Newcomers can also give dynamics to the areas with loss of economic and demographic vitality. We must also be aware about the potential of the diasporas. In this field as in much of others, Couserans has to learn much from the Pays Basque (solidarity). With the municipalities, the new "pays" are territories with strong identity which can find its place in the new territorial grid which is constituted gradually in a regionalized European Union.

CONCLUSION

The laws of 1995, 1999 and 2003 allowed the development of the "pays" as territories having a geographical cohesion, cultural, economic and social, while being carrying federator projects. However, this common denomination hides very different realities, so much on the level of the situations policy, cultural and socioeconomic that on the level of the projects of the territory, about the competences and financial resources. The examples of the Pays Basque in Aquitaine region and Couserans in the Midi-Pyrénées illustrate this extreme diversity. The rise of the "pays" is hindered by various obstacles and competition with other local territories. The comparison between the French Pays Basque and the "pays" of Couserans has enabled to us to better perceive the extreme diversity of the "pays". It also allowed us to better measure the importance of the stakes: vital need of identity, stakes of durable economic development, need for solidarity linked with search for meaning. In a world in full change, the inter-connected people seek reference and identity marks. The "pays" can provide this. They also constitute a suitable territorial framework to apprehend the networks of actors and the cultures with projects as a first step of Proximity Territorial Intelligence, the new "pays" being above all defined as territories of local projects. So much tracks for new works.

  000 in 1846), the evolutions were radically different, the rural migration and economic development having played in favour of the Pays Basque and against the Couserans. The difference also is very marked in terms in dynamics of projects. The Pays Basque is helped by a federative project of territory which began in 1992 with the project Pays Basque 2010, continued in 1997 with the Plan of Development of the Pays Basque, to concretize in 2000 with the adoption of Specific Convention Pays Basque 2001-2006. Thus, the Plan Development of the Pays Basque presented to the CIADT on December 15th, 1997, gave place, on behalf of the State to a Convention of Development to initiate and support operations in waiting of the Plan contract State-Region 2000-2006.