Ioana Galleron
email: ioana.galleron@sorbonne-nouvelle.fr

Fatiha Idmhand
email: fatiha.idmhand@yahoo.es

Daniel Allington

Sarah Brouillette

David Golumbia

' Neoliberal

Anne Burdick

Johanna Drucker

Peter Lunenfeld

Todd Presner

Jeffrey Schnapp

Digital_Humanities

Why Go from Texts to Data, or The Digital Humanities as A Critique of the Humanities

Keywords: Digital Humanities epistemology, SSH research process, haptic thinking, textual data creation, metadata analysis, Hispanic Satellites

Digital humanities are accused of contributing to the decay of Academia in general and of betraying the humanities principles. Through looking at the developments of the field, as well as at its research principles and practices, this article seeks to refute such an allegation, and to show that the passionate debates the digital humanities still raise are related to their critical stance towards 'traditional' SSH research. In the first part, the collaborative and FAIR principles (Findable, Accessible, Interoperable and Reusable) that characterise DH approach are examined, in connection with the dissatisfaction they express towards the established research practices and organisation. Based on an example of the exploration of the archives of the Hispanic 20 th century vanguard, the second part focuses more specifically on the challenges of working with data and of haptic thinking in the literary and cultural fields.

building artefacts that have more to do with Guy Debord's 'society of the spectacle' than with the expectations linked to solid scholarship. [START_REF] Bod | A New History of the Humanities[END_REF] To contest these (mis)representations, scholars in digital humanities have repeatedly advocated that they accomplish humanistic work with computational methods [START_REF] Bordalejo | Digital versus Analogue Textual Scholarship or The Revolution is Just in the Title[END_REF] and that the distance between digital and non-digital approaches is not so great, at least in certain domains. [START_REF] Braillon-Chantraine | Le programme de recherche sur les archives du Fonds Alcides Giraldi: un exemple de production de données en humanités numériques[END_REF] Faced with material concerns, numerous are the digital humanists trying to demonstrate that their practices and demands are not a threat to the humanities, while offering solutions for engaging at a very low cost with the methods and technologies developed in the field. [START_REF] Burdick | Digital_Humanities[END_REF] Most presentations of Digital Humanities curricula or research projects insist on the fact that the objects submitted to scrutiny remain those that matter to humanists in general, and that, in spite of the collaboration with computer scientists, the scholars involved in Digital Humanities are not leaving the field of the humanities. [START_REF] Cecire | When Digital Humanities was in Vogue[END_REF] For the authors of a book such as Digital Humanities, [START_REF]Hacking the Academy: A Book Crowdsourced in One Week[END_REF] or for a philosopher such as Milad Douehi, [START_REF] Dacos | Vers des médias numériques en sciences humaines et sociales: une contribution à l'épanouissement de la place des sciences humaines et sociales dans les sociétés contemporaines[END_REF] the digital is opening the era of a new humanism, as full of possibilities as the one Europe knew during the 16 th century. Other discourses prefer to insist upon the novelty of the results that Digital Humanities can bring onor, put otherwise, on their usefulness. [START_REF] Smedt | Computing in Humanities Education: A European Perspective[END_REF] All in all, the prevalent attitude remains a defensive one, and a clear desire to be accepted by 'traditional' humanists informs such various discourses. This need becomes even more stringent in a context of shrinking SSH research budgets, with digital humanists suspected of 'adapting' to new managerial discourses so as to capture as much money as possible, to the detriment of established disciplinary groups or schools of thought. Digital Humanities appear as furthering the divide between researchers, [START_REF] Debord | La Société du spectacle[END_REF] or even between institutions, 13 since they involve inaccessible logistics and infrastructure for certain individuals, research centres and universities.

Taking a step back from this sparring match between defenders and detractors of the digital humanities, one could point out to the fact that the humanities cannot afford not to take the digital turn, whatever its dangers may be. Nowadays technological and related societal changes are such that it would be foolish to ignore them. Even scholars most attached to pen and paper do not deny the usefulness of digital facilities and devices for accessing, perusing, manipulating and communicating texts and other visual and / or auditive documents. As much as airplanes for covering long distances, computers become unavoidable aids for continuing to produce knowledge within a reasonable timeframe and considering if not all elements, at least an unparalleled number of meaningful occurrences. Whether this aid is limited to 'mechanical' aspects of our work, or involves deeper epistemic and structural changes (a position that the authors of this essay tend to favour, following Matthew Driscol and Elena Pierazzo's arguments), 14 Digital Humanities constitute an unavoidable evolution. As a consequence, digital editing, once practiced by a marginal number of scholars, is rapidly spreading, with an everincreasing number of various electronic libraries multiplying on the net. Still, digital humanities remain surrounded by an aura of suspicion and scandal, and regularly attract virulent criticism, as if, to the difference to other disciplinary innovations and disruptive proposals (such as 'cultural studies', that caused quite a turmoil in the humanities at their beginnings), a full 'normalization' of digital humanities was impossible.

Starting from this astonishment with the amount of passion the debates about the digital humanities still raise, after so many years and so many arguments already produced in favour of the field, our article aims to offer a different understanding of the phenomenon. Keeping ourselves at some distance from the 'economy of promises' 15 in which most defence discourses are rooted, and fully acknowledging the disruptive effect of the digital humanities, our position is to consider that much of the suspicion manifested towards the digital humanities comes from the fact that they expose in sometimes embarrassing ways some limitations of the 'traditional' research, such as the reification of canons necessarily linked to a process of continuous selection of the works, the rhetoric rather than a demonstrative approach adopted in many discourses, or the lack of openness with regards to the sources, the methods and sometimes the results of researches in the SSH. Thus, this article aims at reconsidering the digital turn in the humanities not (only) as an extension of the humanities, or an historical necessity, imposed to the humanists mostly from the outside, but as an answer to older dissatisfactions with established practices, questions, methods and even epistemologies. Most certainly, digital humanities are not the only ones to point towards the flaws of the humanistic researches, but they constitute nowadays, in our opinion, the most articulated effort, rooted in the humanities themselves, to solve these problems. Far from being a form of 'hype'an attitude that digital humanists are the first to reject -, 16 they are fuelled by a hope to radically change the game, thanks to the change in perspective on the sources that the digital brings. As such, they become both the object of much criticism, and a rallying point for other initiatives and innovations in the humanities, as we will try and show in the first part. In the second one, we will turn towards the most salient novelty elements characterizing the digital research, such as the use of 'data' and the exploratory stance they often take, in order to better understand how the digital is trying to change humanistic practices and principles. To do so, we will regularly illustrate our ideas with examples taken from a project in the field of Hispanic literary history, presented here not as a model to be followed, but as a case study helping us to enforce some points in hand.

Digital Responses to Older Dissatisfactions

Digital Humanities were not born yesterday, and, as it has been repeatedly demonstrated, their history dates back to the end of the 1940's. 17 The pervasive feeling about their recentness is probably related to the fact that curricula in digital humanities have not been offered until quite recently in the universitiesroughly at the end of the 1990's and the beginning of the 2000's in the English-speaking countries, and some four or five years later in Europe. 18 Digital humanities have developed, in fact, much more in a 'horizontal' rather than 'vertical' way, with confirmed scholars becoming digital humanistssome would say, 'converting' themselves to the digital tools -, 19 rather than with young students eager to experiment with computers, even if these early career researchers are not absent, of course, from the field. More than any other humanistic discipline, digital humanities are fond of summer schools and other similar short training facilities, not integrated in structured university curricula and suitable, therefore, for further education of researchers more or less recently engaged in a full-time scientific career. As such, digital humanities appear to respond to a desire for change from practitioners who have been sometimes as far as one can go in a discipline, and who come to the digital out of a form of frustration with the methods and questionings they have been trained to. 20 The same frustration is to be read in the tendency of the digital humanities to experiment with new ways for collaborating and scholarly communicating. The organization of a series of 'ThatCamps', also entitled 'non-conferences', 21 is one of the most salient examples of this tendency, but it is not, by far, the only one. While continuing to write books and to publish peer-reviewed papers, conference proceedings and other types of output that are familiar to 'traditional' humanists too, digital scholars engage willingly in the practice of blogging, disseminating findings via social networks, discussing actively more or less arcane questions on diffusion lists, and so on. [START_REF] Fraistat | Data First: Remodeling the Digital Humanities Center[END_REF] Taking a leaf from the scientists' books, digital humanists favour collaborations via projects, and maintain a strong 'maker' culture. [START_REF] Gérard | Palimpsestes[END_REF] Once again, by no way aren't we trying to pretend that digital humanists are the only ones to do so, but their presence in the alternative scholarly communication sphere, as well as the collaborative work tendency, are undeniably extremely high, and relate undoubtedly to some form of frustration with the established ways of circulating new ideas and building new knowledge in the humanities.

Amongst humanists, those promoting digital humanities have also been amongst the first to embrace the open access movement initiated in the so-called 'hard' sciences, [START_REF] Gérard | Seuils[END_REF] and in recent years they became extremely engaged in promoting FAIR principles. [START_REF] Granjon | Critique et humanités numériques. Pour une approche matérialiste de l'immatériel[END_REF] By inviting their researchers to produce datasets, visualizations and interpretations that are findable, accessible, interoperable and reusable, the digital humanities are not only bringing to the fore ideals of openness, cooperation and transparency that are deeply humanistic, but are also questioning preexisting practices and the dominant vision about scholarship in certain SSH disciplines, still strongly articulated around the idea of a scholar working alone on a specific object out of which he or she produces knew knowledge, thanks to his or her intuitions and exceptionally linguistic skills. Admittedly, FAIR principles remain to date much more an appeal, or even a form of wishful thinking, than a reality. However, these drawbacks have much more to do with preexistent reflexes in academia, such as the wish to 'keep' one's work to oneself, or to obscure steps taken to get to a result, than with the specificities of the digital work. It is also important to take into consideration the fact that rendering electronic resources FAIR is not as straightforward as 'traditional' publication via more or less well-established journals and publishing houses. Putting FAIR principles into practice is challenging, especially when this practice concerns large groups of researchers working on diverse objects of study, protected by different copy-right laws and digitized with different principles in mind, as it is the case within the French CAHIER consortium in which the authors of this article are also involved. [START_REF] Greenspan | The Scandal of Digital Humanities[END_REF] Another argument about the dissatisfaction with 'traditional' research that informs the digital humanities and explains the continuous uneasiness they produce, is the very dynamism of the field. Digital humanities seem able to 'absorb' virtually all thematic and ideological innovations in the humanities. In their introduction to the already quoted volume Debates in the Digital Humanities 2016, Klein and Gold describe an expanding movement [START_REF] Himanen | The Hacker Ethic and the Spirit of the Information Age[END_REF] during which Digital Humanities have gradually become aware and tried to solve problems of accessibility and sustainability, while engaging with issues of race and gender (amongst others). Looking at More precisely, they talk about an 'expanded field' in their introduction. See https://dhdebates.gc.cuny.edu/read/untitled/section/14b686b2-bdda-417f-b603-96ae8fbbfd0f#intro [accessed 16 September 2020].

the contents of the above-mentioned book, which turned subsequently in a series of books, one may notice that the 2019 issue made room for a specific section dedicated to 'Ethics, Theories and Practices of Care', alongside with the expected parts speaking about 'possibilities and constraints', 'theories and approaches', 'methods and practices' in the Digital Humanities. Moreover, contributions in these other parts target questions related to 'Gender and Cultural Analytics', 'Critical Black Digital Humanities' or to the 'Digital Working Class', proving thus that the critical and social innovations are deeply inscribed in the digital humanities projects. The very fact that the question 'what are digital humanities?' is still not settled, [START_REF] Hirsch | Digital Humanities Pedagogy: Practices, Principles and Politics[END_REF] goes in the same sense, inviting us to see the field not only as a trading zone 29 or a 'disciplinary common', 30 but as an alternative space of expression for scholars from extremely diverse disciplines who have in common the need to find new outlets for certain ideas, questions and even a way of being, all of which are not exactly welcome in their 'home' disciplines.

Most importantly, digital humanities seem to grow, as much as from technological evolutions, from an acute awareness about the limits of the established scholarly models when it comes to dealing with the complexity of modern-day scientific objects. 31 Since the 18 th century, we assist to a continuous multiplication of sources, to a relentless rediscovery of the past, to the emergence of new forms of contextualization of these discoveries and to the exercise of a perpetual reflexivity upon their ideological, cultural and other idiosyncratic characteristics. In response to this irrepressible expansion and to the densification of the sphere of knowledge, traditional answers have been based on erudition (i. e., reading as much books as possible), specialization (identifying one's field of expertise) and sampling (finding significant occurrences to explain a phenomenon instead of dealing with all elements). But the number of publications becomes such that reading everything, even in a narrow domain of study, becomes almost impossible, while the continuous specialization results in the fragmentation of disciplinary communities into smaller and smaller groups. Sampling, in turn, has led over years to the reification of canons, and even to a culture of 'cherry-picking' when it comes to the administration of the proof. Digital humanities are an attempt to go beyond these limits, or even to escape the fallacy of these responses, so as to build new forms of dealing with complexity that modern day humanities so cruelly need. [START_REF] Klein | Digital Humanities: The Expanded Field[END_REF] Turning towards an example to illustrate both this need and the ways the digital humanities meet it, let us start by remembering that, for decades now, it has been repeatedly observed that the circulation of literature, arts and ideas is too much studied from the perspective of the most known and publicized figures, to the detriment of 'minor' figures. Thus, the profound transformation of plastic, musical, pictorial, architectural, performative and literary arts during the first half of the 20 th century, in Europe as well as in Americas, is almost exclusively related to the activities and proposals of some leading figures, such as, in the Hispanic case, Antonio Gaudí, Santiago Rusiñol, Pablo Picasso, Joan Miró, Salvador Dalí, Ramón Gómez de la Serna, Manuel de Falla, Federico García Lorca or Margarita Xirgu, almost entirely forgetting those who surrounded these stars (close friends, wives, husbands, biographers, etc.) in the convulsive context of Spain and, to a larger extent, Europe during this period. Often constrained to the exile, they played a central role in the large diffusion of the modernist and vanguard ideas. However, information about these 'second fiddles' gets constantly side-lined and a partial view on the phenomenon is perpetuated.

Digital humanities invite to go against this trend, and offer the methodological and even the epistemic equipment it calls for. Instead of focusing on a handful of materials, they invite to engage with full sets of documents and archives, even if these are often unsung, and in many cases, difficult to locate when not irremediably lost. Most certainly, such an invitation raises numerous practical and ideological challenges. On the one hand, one cannot minimize the difficulty to extract and then to cope with the mass of information that such an inclusion necessarily involves, even in a digital approach. On the other hand, the treatment these resources get in the digital spherebeyond the digitization process transforming paper and pictures into pdfs and jpegs, that has been more or less understood and acceptedis undisputedly unsettling. As much as the pretence of analysing ten thousand novels, [START_REF] Koh | A Letter to the Humanities: Digital Humanities Will Not Save You[END_REF] the idea of looking at all the traces produced by second rank figures goes against one of the most cherished principles of literary studies, that recommend personal engagement with documentsan impossible task nowadays, when considering their mass. In addition, computer 'reading' can be seen as impoverishing, with unique documents and (sometime life changers) novels, plays, poems, etc. transformed into 'bags of words' or, more intelligently, in long concordance lists and metadata. Still, this leap from texts to data appears impossible to avoid if we are to move from the focus on a limited number of exceptional individuals towards a more holistic understanding about the apparition and then the adoption of innovative artistic currents or trends. This is not to say that studies based on a qualitative analysis of a handful of examples will become impossible, or that all research will become digital perforce (and this very article, or at least this first part, is a living proof of that, insofar it takes no advantage from corpora or digital technologies to build its arguments). However, building the larger picture will ask more and more for a capacity of handling large amounts of texts and information that only the computer can offer. Instead of trying to sew together piecemeal knowledge produced by specialists, or rather in complement to this delicate operation, the aim is to try and offer a solution for embracing the whole with a unified gaze.

Nor does this mean that personal erudition is not to be gained or respected, or that the computer, or rather digital sources of information, can dispense us from engaging personally with texts and artifacts. Quite interestingly, scholars on classical texts or remote periods, in other words, those working in fields where the erudite model is most necessary and pervasive, because of the accumulation of existing scholarship, embraced quite willingly the digital humanities. [START_REF] Latour | An Attempt at a "Compositionist Manifesto[END_REF] Resistance to Digital Humanities seems, on the contrary, to be more prevalent in the fields where the philological drive is less present, maybe because, as Witmore puts it, 'it gets at the heart of our continued anxieties about the modernist divide and the perceived dignity of human experience as a pathway to knowledge.' [START_REF] Mccarty | Humanities Computing[END_REF] Following the same line of thought, one may plead that this perceived 'treason' by digital humanists is actually the sign of a necessary evolution of all disciplines beyond the traditional divide between the 'two cultures' of scientific [START_REF] Koh | A Letter to the Humanities: Digital Humanities Will Not Save You[END_REF] A pretence informing the seminal Franco Moretti's book Distant Reading (New York: Verso, 2013), and still alive in many projects conducted at the Stanford Literary Lab, available at https://litlab.stanford.edu/ [accessed 16 September 2020]. See also Mark Algee-Hewitt, Erik Fredner and Hannah Walser, 'The Novel as Data', in The Cambridge Companion to the Novel, ed. Eric Bulson (Cambridge: Cambridge University Press, 2018), 189-216. [START_REF] Latour | An Attempt at a "Compositionist Manifesto[END_REF] To give but an example, Willard McCarty, one of the most respected thinkers and practitioners of digital humanities, studies Ovid's poetry and other classical texts. [START_REF] Mccarty | Humanities Computing[END_REF] vs. humanistic inquiry. Following Latour, 36 Witmore observes that the objects we need to study are not purely humanly made, nor entirely naturally given, asking researchers to be able to combine the more scientific fact-finding approach with the reflexivity, contextualization and historicization that characterize more often the humanities. This "compositional" drive is felt on both sides of academia, and while humanists open up to the digital, scientists express in turn an accrued interest for the topics of the humanists, in spite of being sometimes received with mistrust, little understanding or even contempt. [START_REF] Moretti | Distant Reading[END_REF] Far from being a re-enactment of the 'scientolatry', whose pervasive effects have been already felt in the humanities in the 1970's and 1980's, duringalbeit not in strict relation tothe flourishing decades of structuralism, digital humanities appear thus as a new attempt to build a meaningful dialogue between fields that the erudite-specialization-sampling model has put widely apart.

Humanities as Data Science

Beyond the enumeration of these symptoms of dissatisfaction with traditional humanities research manifested in the sphere of digital humanities, it is time now to take a closer look at how they are affecting the actual research processes as a consequence of their desire to take some distance with the established protocols and to deal with complexity in new ways. The answer to such a question is not easy, because of the already mentioned sheer diversity of disciplines and objects of study, covered by both the digital and the non-digital humanities. However, on the basis of our experience, grounded in text analysis and literary history, we may pose that digital humanities affect all the major steps through which a researcher creates new knowledge.

Simplifying outrageously for the sake of the argument, one may say that a research process goes from an idea (an intuition, a curiosity…), to the publication of the findings, passing in a more or less linear way through phases of material gathering, analysis, and paper writing. For reasons of space, we will leave aside the last two steps (paper writing and publication), on which we have already made some observations, and about which one can read illuminating contributions in a recent book edited by Jennifer Edmond. 38 As a preliminary, it is important to underline that the differences we address in what follows are not always to be found in all digital researches, and that these often include several non-digital methods and techniques alongside specific practices we describe.

Out of the three 'traditional' responses to the complexity above-mentioned, digital humanities seem to concentrate first and foremost on the transformation of the sampling procedure at the core of humanities research, strongly affecting thus the material gathering phase. As opposed to the identification of main ideas, expressions, structures of a text, on which 'close reading' rests, digital humanities proceed to the creation of data. The process is far from being straightforward, considering the competing views and definitions about what is data in a document, especially in the literary analysis field with which we are more familiar. Situated at various levels, [START_REF] Pierazzo | A Rationale of Digital Documentary Editions[END_REF] they pose multiple problems of identification, tagging and articulation, that best practices and recommendations, such as TEI or Dublin-Core, do not entirely solve. In spite of these limitations, the interest of a data approach is the call to a systematic, uniform and complete treatment of the sources, [START_REF] Rockwell | What Is Text Analysis, Really?[END_REF] with no preconceived idea about what is to be found in these and no premature filtering out of elements that do not fit a more or less articulated interpretative scheme. From a traditional humanistic perspective, such an approach raises multiple questions, related to the added value of such an enterprise. We will endeavour to answer these concerns in turn.

In the case study described here, the creation of data started with the digitization of all manuscripts, letters, images, pictures, sounds and movies produced by 'satellites'. [START_REF] Schnapp | Digital Humanities Manifesto[END_REF] In a second step, metadata have been attached to all documents, and a great amount of work has been put into a rich description of the supports, formats, relationships and contents, going largely beyond the recommendations for minimal metadata sets, aimed mainly at facilitating the harvesting of the resources by internet crawlers. Such an effort can be judged disproportionate, considering the time it consumed as opposed to the little interpretative results it yielded (as yet). This would be to forget that the metadata thus created can serve not only to the scholar or the project that produced them, at a specific point in time, but to future researches, conducted by the project owners or by their peers. To the difference to the manual gathering of material in a 'traditional' research project, one of the main values of data produced in a digital humanities approach is thus its reusability. Therefore, new forms of collaboration are stimulated and a faster engagement with sources becomes possible.

Another reason of defiance towards the process of data creation seems to be related to the very ambivalent position of humanities scholars towards exhaustivity. On the one hand, there is a claim, more implicitly than explicitly made towards peers and early career researchers, to be exhaustive in their bibliography, whether this is to be understood as covering research undertaken by others on the same topic, or primary sources that the research is supposed to exploit, or both. On the other hand, when it comes to the contents themselves, the exhaustivity does not seem to be as important to humanists as a clever analysis of some elements and case studies. The processes for acquiring and curating large (or even full) datasets may appear therefore as a solution for an inexistent demand, and even more as a nuisance since it mobilizes time and intelligence for dealing with what may be finally judged as a lot of uninteresting occurrences. Digital Humanists interrogate, in turn, the validity of a discourse of knowledge based on a handful of examples, over-interpreted or poorly projected on a whole dataset. Exhaustive data allow cross-checking and support refutability, a Popperian principle to which digital humanists, closer in this respect to the 'hard sciences', are profoundly attached. In other words, creating exhaustive data is accepting to be more completely exposed to the criticism of the peers, and to pay the psychological and cognitive costs that such a criticism entails. If the story of the research in the humanities is, at least partially, one of a slow distancing from the even characters or phonemes can be data, or, on the contrary, long spans of texts can be isolated and defined as such. [START_REF] Rockwell | What Is Text Analysis, Really?[END_REF] To give but one example, if it has been decided that sentences form a type of data in a text, then all sentences must be marked up, or at least one must have a clear indication about the types of sentences that are marked up and the ones left aside. authority principle, or rather one of a change in what makes authority, [START_REF] Stewart | The Paratexts of Inanimate Alice: Thresholds, Genre Expectations and Status[END_REF] it can be derived that digital humanities are indeed helping to push forward the work of the humanities.

A frequent reproach made to data creation in humanistic discipline is that it impoverishes texts. In the process of identifying all occurrences of a phenomenon, the overall sense gets supposedly lost for the sake of a delusional 'objectivity'. This is to ignore to what extent, at every step, digital humanists are aware that data creation involves interpretation, and therefore a form of 'text enrichment'. As Johanna Drucker has put it, 'data are capta', 43 and, as such, they involve subjectivity, or even hidden assumptions and personal agendas. In a different context, the authors of the reports produced within the K-Plex project observe that 'in fact, "big data" approaches are highly selective'. [START_REF] Teissier | Les Humanités numériques, combien de divisions? Éléments pour une sociologie critique de curricula d'éducation au numérique en sciences humaines[END_REF] This in turn exposes digital humanists to the reproach of objectifying partial views. Interestingly, similar concerns are seldom voiced about traditional research in literature, in spite of longstanding practices in the field of filtering, diminishing and discarding information about less known books, authors and journals. The real difference is that digital humanities projects, such as 'Satellites', have built-in mechanisms for recording all these filtering operations, allowing future scholars to reconstitute at will the continents lost. It may well be that the mistrust with which they are faced translates in some cases the uneasiness of non-digital processes of being held to similar transparency standards.

Moving from data creation to data analysisor, in other terms, from the material gathering to the interpretation stepanother important change brought by digital humanities to the research process is the complete upheaval it can produce in this more or less linear movement because of the possibility to approach the objects of study with no preliminary hypothesis or articulated aim. As Geoffrey Rockwell puts it, the starting point of a digital research is sometimes 'free floating stuff. That stuff wasn't driven by research questions though. It was more solutions looking for a problem. There were these interesting text analysis methodologies and techniques, impressive statistical approaches to stylometry, etc., that just made my fingers tingle to get hands-on and to apply them to concrete problems. A friend of mine called this "haptic thinking", a way of developing thoughts and new insights through using your keyboard.' 45 As it has been repeatedly observed, digital humanities research may develop from playing with datasets and testing various lines on inquiry on them, whether these lines of inquiry relate to a genuine, pre-existent interest of the researcher, or are completely made up as a part of a training program. 46 This kind of 'haptic thinking' is not new in several disciplines (linguistics, sociology, geography, etc.), where data gathering is also a well-established practice, and in these fields the digital turn brought mainly speed, breadth and accuracy. Other disciplines opening to the digital, such as literary analysis, come slower to such an approach. In the 'Satellites' project, haptic thinking has been adopted once working with metadata from a traditional perspective proved insufficient. Indeed, in a first step, metadata has been understood and exploited following Genette's proposal in his famous works, Palimpsestes and Seuils 47 ; since it includes titles, subtitles, authors' names and numerous other generic indications that guide the reception of the resource and its 'consumption', while defining its 'presence in the world' 48 , metadata can be seen as embodying in the digital sphere the editorial paratext. 49 As such, it acts in similar ways as a 'threshold', an 'indecisive' zone between the inside and the outside of the bookhere, of the digital object. It can, therefore, be used for the same purposes as the perusal of a paratext, mainly for the preparation of the text analysis. In the same way as the print medium, but faster thanks to digital interrogation protocols, consideration of dates helps to avoid misunderstandings and anachronisms, potential summaries give a general understanding on what the text is about, a presentation of the author's background helps to connect its themes with a context or an artistic trend, and so on. Thus, a distant reading of the dates associated to documents related to José Mora Guarnido, Carlos Denis Molina or Fernando Aínsa's facilitate the identification of their most creative writing periods; an interrogation by type of document allows to rapidly group together press articles, essays or correspondences, while a search by subjects and keywords facilitates crossing themes. To some extent, metadata creation and analyses corresponds therefore to the traditional practices of sampling and to the identification of the themes needed for a demonstration.

However, beyond these uses the very existence of rich metadata in the fluid electronic format allows to adopt a more playful stance, and to provoke serendipity. In the 'Satellites' project, haptic thinking led to the application of algorithms of recommendation, developed with very different purposes in mind, to a portion of the metadata created during the digitization process.

Since 1990's, recommendation has become one of the most frequent application of machine-learning methods, either supervised, unsupervised or based on reinforcing procedures. 50 Based on the so-called 'filtering algorithms' to create predictions either from common points identified in the past so as to predict a 'future' 51 or from assumed similarities to suggest possibilities, 52 it is the most widely used form of artificial intelligence in various fields of knowledge or practical activities. From recommendations of movies to watch, to the suggestions of products to buy or of personalized online radio, many websites and devices run machine-learning algorithms at the heart of their systems. The same ones intervene to produce reliable predictions and decisions on new data, or to discover relationships and implicit knowledge from existing data, in biology and tribology, economics, social studies, and so on. However, recommendation as a way to explore large volumes of data has not been experimented with in literary studies, which seem by nature too far from the applicative domains of this form of computer studies. As it turned out, recommendation can however help to identify new associations, patterns or unknown relations between one or more authors in a quicker, more efficient and productive ways than the traditional reading and sampling approaches.

Three authors' archives were selected, each one containing about 1700 documents described with 30 to 40 metadata fields, for a total amount of some 50.000 information points. In a first step, a 'gradient boosting algorithm' was trained on the basis of two thirds of the documents and two metadata fields, namely 'state of the documents' (with three possible values: 'good', 'medium' and 'bad'), and 'document language(s)' ('Spanish', 'English', 'French', 'Portuguese'). When asked to make predictions on the test corpus, the machine guessed right with an accuracy of about 87%, that has been judged correct enough for pursuing the experiment.

A tool called 'Link&Pred' has been developed to model the authors as nodes, and the links between them as parameterized edges with a weight that represents the degree of commonality between them. As input, the (curated) data were presented in a CSV file. Inside the system, they were converted into a graph file through calculations that took into consideration the life and creative periods of the authors (in other words, the periods during which they could have collaborated), the keywords attached to the documents they produced, or linked to them, and the subjects they shared. On this basis, the system was asked to predict their potential relationships, understood here as intellectual proximity or similarity. 53 Different link prediction algorithms were analysed and tested (Common Neighbours, Adamic Adar, Preferential attachment, Resource Allocation, etc.) until finding the algorithms with the highest results (92 to 97% with SimRank and CommonNeighbors). We obtained then a visualization showing pairs of authors as nodes on the graph, whose relationship is established as follows: the higher the score (greater than 1.0), the greater the possibility of an intellectual link between these two authors. As expected, evident relations emerged clearly between known authors belonging to the same school of thought, but other, unexpected links were brought to the fore, such as those identified in Fernando Aínsa's correspondence. 54 From 1974 to 1999, Aínsa has been the director for literary publishing at UNESCO. This prestigious position put him in contact with numerous outstanding figures in publishing industries, as well as in the cultural and literary sectors; it also enabled him to help disseminating Latin-American literature on both sides of the ocean. A 'traditional' approach to his correspondence involves a chronological reading of his letters, looking at each text so as to identify networks, shared passions and themes; discovery takes time and, in many cases, a great deal of luck. Link&Pred allows to go much faster, and in some way in a surer way, insofar it observes regularities and points towards several interesting letters. Thus, through analysing metadata of 1835 letters written from 1972 to 1988, the tool puts to the fore the links between Fernando Aínsa and Julio and Iris Ricci, on the one side, Fernando Aínsa and the New Yorker translator and academic Clark M. Zlotchew, on the other sidebut also, more unexpectedly, between the Ricci and Zlotchew. A return to the texts showed, indeed, that the Ricci and Zlotchew met in New York, became friends, and that this friendship is the key facilitator in the diffusion in the USA of two works by Fernando Aínsa, Con acento extranjero and Las palomas de Rodrigo. Other similar suggestions may help to draw a larger picture of the networks who contributed to the penetration of Aínsa's ideas and works in the North-American academic circles, and to analyse the chronology of his growing influence.

Beyond doubt, the research process cannot stop at the identification of such links and potential similarities. Recommendation algorithms make suggestions, but do not pretend to replace analytical work. Without contextualization, masses of data have very little value and recommendations are unusable, or can even become dangerous, by locking the researcher in a specific theme or way of thinking, without the possibility of opening up to other perspectives. But understanding machine possibilities and opening up to methods developed in computer science allow to engage in more complete ways with our objects of study. Far from pretending to offer blue-prints for research and maps to discovery, digital humanities remain thus profoundly humanistic in their attachment to a serendipity principle, that machines may boost, but not replace. 53 The prediction system described here has been developed by Laifa Ghani as part of his internship during spring 2019 within the Institut des Textes et Manuscrits Modernes (Paris, UMR8132, Archivos team). The system is actually in the process of being further improved. 54 See https://ainsa.nakalona.fr/ [accessed 16 September 2020].

Conclusions

Digital Humanities may be sometimes synonymous to an excess of technologisation. There is a rush towards new techniques, new software, rather than taking the time to fully exploit the ones we have in hand. Another identifiable trend is that of creating digital artefacts for the sake of digital artefactsdatabases and digital editions whose intellectual exploitation is perpetually postponed, or that are minimally exploited. Also, having a clear understanding about what a visualization can say, or building an inspirational interpretation on the basis of the results of a program, is still work in process, at least in literary studies. But this is less a fault of digital humanities themselves, and rather the continuation in a digital paradigm of older reflexes in academia, such as the complacency in text perusal, description and paraphrase instead of building new knowledge and seeking for wisdom.

So far, the digital humanities do not fulfil their potential, for a whole range of reasons. To start with, they remain characterized by a form of fragility, both of their inputs and of their outputs: digital data is menaced by all types of obsolescence, of the materials, of the file types, of the contents, and so on. Data creation proves to be an unfinished, perpetually incomplete endeavour (as opposed to the 'final product' standard that goes with book publishing), and a culture of the 'perpetual prototype' characterizes most of the products, especially but not only in digital scholarly editing; [START_REF] Elena | A Rationale of Digital Documentary Editions[END_REF] subsequently, the papers we produce are more often reports about newer or older projects, links towards milestones, rather than 'definitive' words on a matter. A particular handicap created by the culture of data handling is the dependency on storage facilities, interfaces and tool maintenance. The ecosystem of scholarly validation, on which digital humanities are even more dependent than their non-digital counterpart, for the reasons shown above, is still in the process of strengthening. But these drawbacks do not overshadow the advances the digital brings to the humanities, whether in terms respecting their fundamental principles or when it comes to the results obtained.

A last aspect in which digital humanities may be said to depart radically from the disciplines they are stemming from may be their refusal to fully adhere to the long-told story of the modern 'decay' of the university. From a Digital Humanities point of view, it is all too easy to pretend that pre-digital, pre-neo-liberal university was a paradise in which critical thinking and solid scholarship were the sole goals of academia. In the name of reflexivity, how many proceedings gathering papers vaguely related to a theme, where authors take a key word as a motive for accumulating quotations that lead to nothing? In the name of historicization, how much bibliographic showing off? The interference of various agendas with the research of the truth is not new, and if one could get back in time it would be difficult to decide in what era precisely one should regress in order to live in a world closer to academic ideal(s). A factual comparison of students' trajectories may well show that a doctoral candidate benefits from a much fairer treatment in 2020 than in 1960 or 1970. If success and employment in research fields were higher in the middle of the 20 th century, this may very well have much more to do with the limited numbers and elitist characteristics of doctoral studies of the time, than with the structure of the academic system of the era. Rather than deploring a paradise lost and turning solely towards external menaces to the academia (whose existence is most certainly not to be denied), digital humanities remain characterized by a 'critical self-consciousness' [START_REF] Drucker | Speculative Computing: Aesthetic Provocations in Humanities Computing[END_REF] and are looking to improve the situation by upsetting the apple cart in our own humanities shop. And they do so deliberatelynot because they are fanatical technology-mongers, barbaric or snob, but because they are humanistic. Umanitățile numerice (sau digitale) sunt acuzate pentru contribuţia la decadența standardelor academice, și pentru trădarea principiilor umaniste. Scopul acestui articol este să combată aceste acuzații. Prin analiza evoluțiilor pe care le-au cunoscut umanitățile digitale, precum și a principiilor și a practicilor care pot fi observate în acest câmp de cercetare, încercăm să arătăm că dezbaterile pasionate care continuă în legătură cu umanitățile numerice sunt legate de poziția critică pe care o iau cu privire la cercetarea ,,tradițională" în știintele umaniste și sociale. În prima parte a articolului, vom vorbi despre principiile colaborative și FAIR care caracterizează umanitățile digitale, pentru a arăta că aceste principii și practici exprimă o formă de insatisfacție față de organizarea umanităților și față de practicile curente în acest domeniu. A doua parte este bazată pe un exemplu concret de explorare a unor documente de arhivă produse de câțiva membri ai avangardei hispanice din secolul XX. Obiectivul celei de-a doua părți este să arate în mod concret care sunt problemele și dificultățile legate de lucrul cu date numerice, precum și adoptarea unei gândiri haptice în domeniul literar și cultural.

  Michael Witmore, 'Latour, the Digital Humanities, and the Divided Kingdom of Knowledge', New Literary History 47.2-3 (2016): 353-75; available at https://doi.org/10.1353/nlh.2016.0018 [accessed 16 September 2020].

De la text la date, sau Umanitățile numerice drept critică a cercetării în știintele umaniste

  6. https://thatcamp.org/about/ 7. https://teach.dariah.eu/course/ 8. https://www.go-fair.org/fair-principles/ 9. https://cahier.hypotheses.org/le-consortium

See Adeline Koh, 'A Letter to the Humanities: Digital Humanities Will Not Save You'; available at https://hybridpedagogy.org/a-letter-to-the-humanities-dh-will-not-save-you/ [accessed15 September 2020]

These dissemination activities are to be seen not only as a complement, but even as a will to 'hack the academy'. See Dan Cohen and Tom Scheinfeldt (eds.), Hacking the Academy: A Book Crowdsourced in One Week (Ann Arbor: Digital Culture Book and University of Michigan, 2011), otherwise debated upon in the review-section of the present issue, as well as Pekka Himanen, The Hacker Ethic and the Spirit of the Information Age (New York: Random House, 2001).

See for instance the course on 'Design Thinking and Maker Culture' offered on DariahTeach Website; available at https://teach.dariah.eu/course/view.php?id=54&section=0 [accessed 16 September 2020].

Let us remember here that the first platform for open access papers, ArXiv, was launched in 1991 by a physicist. On the history of Open Access, see Peter Suber, Open Access (Cambridge, MA: The MIT Press, 2012).

Findable, Accessible, Interoperable and Reusable. See https://www.go-fair.org/fair-principles/ [accessed 16 September 2020].

For a presentation of CAHIER, see https://cahier.hypotheses.org/le-consortium [accessed 16 September 2020].

Very different types of researchers exist in the Digital Humanities, when looking at their disciplinary background and centres of interest. There are literary and historical digital humanities, digital humanities

 [START_REF] Schnapp | Digital Humanities Manifesto[END_REF]We call 'satellites' all the less-known figures of the Hispanic vanguard mentioned above. By digitization, we mean here the mere action of producing a digital equivalent of the initial document. For more information about the whole process, see the 'About' pages concerning each author, for example https://guarnido.nakalona.fr/about, https://molina.nakalona.fr/about, https://ainsa.nakalona.fr/about [accessed 16 September 2020], as well as Cécile Braillon-Chantraine, André Davignon, Nicolas Lahoche, Fatiha Idmhand, Cécile Martini, 'Le programme de recherche sur les archives du Fonds Alcides Giraldi: un exemple de production de données en humanités numériques', Revue des Nouvelles Technologies de l'Information, Hermann, special issue 'Fouille de Données et Humanités Numériques' ( 2014): 169-84 ; available at https://halshs.archives-ouvertes.fr/halshs-01132614. [accessed 16 September 2020]. All corpora are freely accessible on NAKALA, a French infrastructure provided by HumaNum; available at https://www.nakala.fr/ [accessed 16 September 2020].


Mathieu Veron

Hélène Fargier
email: fargier@irit.fr

Michel Aldanondo
email: michel.aldanondo@enstimac.fr

H~l~ne Fargier

From CSP to configuration problems

come

Introduction

Configuring a product is to choose a feasible instance of this product among all its variations. Hence configuration is a search problem over a search space defined by a model of a configurable product. This model is composed of the description of all the attributes, characterizing it, the allowed values for these attributes and the constraints expressing incompatible values [START_REF] Mittal | Towards a generic model of configuration tasks[END_REF]. According to this definition of a model, the Configuration Problem can be mapped into a constraint problem. Whereas the configuration software (configurators) were implemented like expert systems (RI I/ XCON, McDermot 1982), the Constraint Satisfaction Problem (CSP) framework is now preferred due to its knowledge representation which is declarative and context free (for further discussion about pro and cons of both approaches see Gelle and Weigel 1996). Our experience in the field of configurator and configurable product modeling, acquired after near ten years of activity in the configurator industry, points out that the CSP framework is not able to the specificity of the configuration problem capture entirely and easily, hence the need for a more complex model to represent a configurable product and the relevant algorithms. After reviewing, in a first section, a list of further requirements. We will analyze how previous work in the field handle these needs and the solutions they provide to manage them, with a particular focus on constraint based approach. Finally we will provide some ideas for the problem definition and its resolution. The conclusion will introduce some further work on this model.

Requirements to a configuration problem Basic Configuration Problem

A configurable product is classically defined by a set of attributes (or components) which possible values belong a finite set, and a set of feasibility constraints over these attributes which specify their compatible combinations of values. The problem is to find a feasible product (i.e. to choose a value for each attribute) that satisfies not only the feasibility constraints but also some user requirements. In a first basic approach one could consider that each of these requirements concerns one attribute. In this case, the Constraint Satisfaction Problem (CSP) [START_REF] Mackworth | Constraint Satisfaction[END_REF]) offers a suitable framework. A CSP is indeed described by a triplet = {X, D, C}, where X is a set of variables, D a set of finite domains (one for each variable) and C a set constraints. A constraint c ~ C is defined by a set S(c)={ i,j,...m} variables and R(c) a subset of Di x Dj x ... Dm expressing the combinations of instantiations of these variables that satisfy the constraint. A constraint c is said to be valid with respect to a partial instantiation s, if the projection of s over S(c) is included in R(c). A solution CSP problem is an instantiation of all variables such that all constraints are valid.

The mapping is then obvious: the variables are the attributes of the product, and the constraints encode both the requirements (by means of unary constraints) and the feasibility constraints.

Need to manage the states of the objects

In a classical CSP, a solution is a consistent instantiation of all the variables. But in a configuration problem, all the variables do not need to be valuated in order to consider the configuration completed. On one hand, the valuation of some variables is optional (the optional variables can be 101

From: AAAI Technical Report WS-99-05. Compilation copyright © 1999, AAAI (www.aaai.org). All rights reserved.

left uninstantiated at the end of the configuration process).

Hence, the set of variables X has to be partitioned into two subsets Xm and Xo (the mandatory variables and the optional variables) and an instantiation d of a set of variables Y such that Y included Xm is a solution of the configuration problem if and only if it satisfies all the constraints pertaining to Y.

On the other hand, some variables are exclusive, in the way that the valuation of the first one forbids the valuation of the second one and reciprocally: they cannot participate in a solution simultaneously. For instance, the user cannot choose simultaneously a CD drive and a DVD drive when configuring a PC. Moreover, the possibility to provide a value to a variable can depend on the value taken by another one: as soon as the type of the disk driver is SCSI, the user has to choose a SCSI card -but he cannot configure such a card if he has chosen an IDE driver.

Hence, we need to handle the notion of state of a variable (active or not, if active optional or mandatory) and encode the previous activity conditions over the states. A first solution could be to add a dummy value within the domain of each variable (let's name it 0) and to modify the set of constraints in order to capture the activity conditions: 0 is the only valid value for y if the activation condition of y is not satisfied. Although this kind of approach allows the use of the classical CSP framework, it requires to merge feasibility constraints and activity conditions. Handling the states of the variables more explicitly not only overcomes this drawback but also allows the expression of other possible states (e.g. optional, mandatory, etc).

Under this assumption, we need to slightly modify the definition of a complete configuration in the following way: an elementary configurable product is completed if and only if a consistent instantiation for all its active and mandatory variables exists. A configurable product is then completed if and only if all its mandatory sub-components are completed.

In order to be able to easily reuse sub-components inside another configurable product, we have identified a condition of self-sufficiency for configurable products. This condition states that no outside knowledge is necessary, all the references are internal. In our model, this is translated by a property on the constraints: ¯ the transversal constraints only involve attributes of configurable products (elementary or not) included inside the configurable product that need to be reused~ the state conditions only involve state variables of attributes and configurable products (elementary or not) included inside the configurable product that need to be reused. We are now able to reuse any sub-component into other configurable products. For example a car manufacturer, who sells cars and vans, can isolate a sub-product "seat" in each configurable product. The sub-product "seat" is modeled only once and reused in both configurable products (Car and Van). Another benefit of such a decomposition deals with the expression of activity conditions: a unique rule can describe the fact that the same condition controls the existence of all the variables of a sub-prodtlct.

Need to manage the Structural decomposition

Structural decomposition is a strong issue for the configuration problem. The technical analysis of a configurable product clearly shows the interest of a decomposition in sub-components that can involve their own internal constraints. For products made from the assembly of sub-parts, this decomposition is mainly the bill of materials. But, in more complex configurations, a subcomponent can be itself a configurable product. Hence we distinguish the notion of elementary configurable product: an elementary configurable product is a self-containing entity defined as previously in terms of attributes, domains and internal constraints. In this context, a configurable product can be: ¯ either a single elementary configurable product, ¯ or a collection of : ¯standard components (not configurable product as raw material or bought components) ¯ and/or configurable products (elementary or not), the attributes of which can be related by a set of transversal constraints, i.e. constraint on the value of any attribute.

Need to make the distinction between functions and standard components

Configuration problems can be classified according to their complexity (Gartner Group 1997). From the lowest level complexity to the highest, we most often find: ¯Pick-to-order (PTO) problems, standard components are just picked from a catalog, with very few compatibility constraints on the possible configurations. ¯Assemble-to-order (ATO) problems, standard components must be chosen according to compatibility constraints plus some constraints that restrict the possible assemblies. The classical example of ATO is personal computer configuration. ¯Build-to-order (BTO) problems, components are not required to be standard, but can be tailored. In this case, the product can be structured into sub-products and recursively.

In Build-to-order problems, the physical components of the decomposition are not identified, the only specification the usei can give is in term of functions. But even in problem involving only standard components, the user does not always hold the required technical background to choose standards components and can find interest in expressing functional needs. For instance, a PC buyer does not always know the difference between one hard drive and another, but he knows that he wants a fast hard drive with a large capacity. The description of functional needs requires the use of both discrete and continuous variables. Moreover, in any case after configuring functions, a matching from functions to components or, in the case of build-to-order, from functions to manufacturing orders has to be computed.

Need to manage the interaetivity

The human user has a particular place in the configuration process. It is obvious for configurators dedicated to the selling process, but we have encountered many cases in the back-office where the problem and the optimization criteria could not been completely specified, and had to be left to human appreciation. CSP algorithms are designed for batch processing, i.e. looking blindly for a solution. But, in a configuration process, the choice of the values is due to the user, interactively.

The main goal to be achieved by a configurator is to guarantee at each step (i.e. after each user choice) that the partially specified product is feasible. In the CSP framework this could be expressed by enforcing global consistency after each user choice. Because global consistency is a very costly operation, local consistency is often the only level of consistency that can be achieved in real-time. But in this case, a mechanism that warns the user of the detection of inconsistency needs to be provided; for example a "backtrack-point" could be identified to help the user to restore consistency. More generally, providing help and explanations are key issues to configuration and Interactive CSP. Moreover, our experience shows that some internal hidden attributes are often defined by the experts when modeling the configurable product. Such variables are not under the user control (i.e. cannot be valued interactively) but correspond to technical parameters or intermediate calculations and are used within functional constraints.

Parallel with previous research

Previous research on configurations has addressed one or more of those requirements. In the following we will review some previous work with an emphasis on constraint-based configurators.

Mittal and Frayman [START_REF] Mittal | Towards a generic model of configuration tasks[END_REF] present definition of the configuration problem. They work on personal computer configuration and their definition is oriented toward assemble-to-order. This seminal work clearly outlines the need for a functional definition of configurable products and for mapping mechanisms that find out the component decomposition. Nevertheless, it only deals with the assembly of a predefined set of components and so fails to support tailored products (i.e. build-to-order problems).

Esther Gelle and Rainer Weigel (Gelle and Weigel 1996) claim that the spectrum of configuration problems is wider than the assembly of predefined components. That's why they propose an incremental model that simultaneously handles discrete and continuous variables. Hence this model allows the expression of functional descriptions as well as component assemblies.

Gelle and Weigel actually propose to enhance Incremental CSP (Mittal and Falkeiner 1990) with an algorithm able ensure global consistency over continuous domains after each user choice. The idea behind ICSP for configuration tasks is that the solution space is often so huge and the interactions between variables so complex, that the whole problem cannot be handled entirely. That's why the problem is restricted to "active" variables. The activity of a variable is derived from special constraints called "Activity Constraints (AC)". The traditional "Compatibility Constraints (CC)" are evaluated once all the variables involved in the constraint are active. The activity constraints are also used to represent configurable products. In Gelle and Wiegel's model, each object (i.e. configurable product) has a type and attributes, but the list of attributes is not predefined but is dynamically conditioned by the selected type. Let's take an example: the 'engine' object takes is type over two kinds of engines ('Gasoline' or 'Diesel'), which are described by two activity constraints: ACI :Engine=Gasoline -9 Engine.GI ~ gl, Engine.G2 g2, Engine.G3 ~ g3 AC2 : Engine=Diesel -9 Engine.DI ~ dl, Engine.D2 d2 Where gl,g2,g3 and dl,d2 are the respective domains of the attributes GI,G2,G3,DI,D2. So if the type of engine is Gasoline then engine is described by three attributes: GI, G2. and G3; but if the type chosen were Diesel engine would be described by two attributes: DI and D2.

To handle real assembly-to-order problems, attributes are considered as "connectors" and the domain of each attribute is the list of components that can be connected to that connector.

The activity state over object responds to our object state need, but it is not expressive enough due to its Boolean nature. Although the mechanism of Activity Constraint provides a uniform way to model configurable products and to manage an activity state for each object, this paradigm fails to isolate self-sufficient products (attributes and internal constraints) for reusability purpose. Indeed all the activity constraints are expressed at the same level and no structuration tool is provided that could help gathering all the constraints relevant for a particular sub-product.

These drawbacks are avoided by the Composite Constraint Satisfaction Problem (CCSP) framework proposed (Freuder and Sabin 1996) to handle the Configuration Prol~iem. Informally, CCSPs are CSPs where domains can contain sub-problems : when a variable is instantiated with a sub-problem, it is replaced by this CSP. More formally, given a CSP P=(V,Dv;Cv), if Xi e V is given the value P'=(Xv',Dv',Cv') then P becomes P"=( V t..) V' / {Xi}, u Dv' / {Dxi}, Cv ~o Cv' u C{v',v} / C{Xi}). The main configurable product is thus represented by an initial CCSP, composed of some variables whose domains are sub-CCSPs : this sub-problem represents the direct sub-component of the main product. This defines a hierarchy which reflects the structural decomposition. The leaves of the tree correspond to our elementary configurable products. Hence this model explicitly shows out the structural decomposition and the replacement mechanism keeps the problem as simple as possible. But it lacks mechanisms to handle full interactions with a human user. Indeed, suppose that the user had previously made a choice over a variable, thus selecting a sub-problem and that later, he changes his mind, he cannot modify his previous choice since the variable is no longer available due to the replacement mechanism. This could be overcome by maintaining all the variables within the problem, but the CCSP model would suffer an increase in complexity.

We can find in previous work some answers to the needs identified in the first section, but none manages all of them. Hence we will expose a (partial) solution in terms of data structure and management levels able to handle all these requirements.

How to handle these requirements

According to our analysis in Section II, one of the main requirements for a configurator is the ability to handle the structural decomposition of configurable products. That's why we propose to model a configurable product by a tree with : ¯ internal nodes representing the sub-configurable products (the root being the main one) ¯leaves corresponding to variables of either an elementary configurable product or standard products.

It appears in Section 11.2 that we need to manage the state of the components of the tree, that can be active or not (i.e. accessible to the user or not). Moreover, an active component can be (i) optional or mandatory and (ii) completed by the user or not.

Related to these two needs, we have identified a condition of self-sufficiency of configurable product (see section II.3). In order to guarantee this condition, we have defined a configurable product as :

¯ a collection of sub-components, ¯a set of constraints such that each variable involved in these constraints appears in a sub-problem, ¯ one state variable for each sub-component, ¯ a set of state conditions over any state variable appearing in this product or in a sub-product. For the sake of clarity, we will assume in the following that selecting a standard component is modeled by an attribute whose domain is the list of the codes of the standard components. A trivial matching mechanism is responsible for listing the selected one into the final bill of materials decomposition.

More formally:

Definition: a quartet { Lsc ¯ Lsc is the partitioned denoting a configurable product (CP for short) is , Cv, S, Cs} where: list of the sub-components of CP. It can be into two subsets Lcp and Lecp respectively set of non elementary CPs and a set of elementary CPs. The set of included variables of a configurable product cp is denoted riv(cp) and recursively defined by : ¯ riv(cp) is the set of variables of cp if cp is elementary configurable product, ¯riv(cp) = Ucp. ~ L~p riv(cp') if cp is a non elementary CP.' C is a set of constraints over the set riv(cp). These constraints encode the feasible, (or unfeasible) combinations of values for the attributes.

S is a set of state variables, one for each sub-component. Cs is a set of state conditions over the set of included state variables of the products or of their subcomponents and recursively.

The idea underlying this definition is the use of a two level configuration engine. A first level is responsible for the management of the tree structure and for the control of the state variables, whereas the second level involves the CSP mechanisms to maintain the domains of the configuration variables. The user is responsible for adding/retracting unary constraints on the active variables in order to express his choices, a constraint propagation mechanism on the second level CSP will erase the inconsistent values in the other domain.

First level : object management

The main goal of this level is to maintain a state for each object of the tree structure. The value of a state variable depends on: ¯(i) the value of the state variable that represents the upper product in the hierarchy: a sub-component cannot be active if is container is not active; ¯(ii) the state of its sub-components: a configurable product is completed if and only if all its subcomponents are completed; ¯(iii) on user actions: a variable is completed whenever has been restricted to a singleton by the user, ¯(iv) on state conditions (Cs) inserted in the model enforce a particular state.

Let us now explain what kind of state conditions we handle, and how they are managed. In Section II.2, we explain how conditions can describe that an object is optional or not and when an object is active or not.

Hence Thus we define a constraint problem made of a set of configuration and state variables (each one taking its value in a finite domain {0,1,2,3}) and a set of constraints. In order to ensure a coherent configuration process, the states need to be consistent with each other; this implies maintaining global consistency over the CSP.

Here is an example of such a constraint problem on the basis of the previous example taken : let there be four variables, cd_drive ¢ {24x, 36x, 40x}, dvd_drive ~ {2x, 5x}, option_package ¢ {none, std, deluxe} and extra_warranty ~ { lyear, 2years, 3years}. To express that cd drive and dvd_drive are exclusive and that the deluxe option package implies an extra warranty, we will define the following constraints : Second Level : Constraint management on value In order to deal with the basic requirements of a configuration problem, i.e. finding a consistent instantiation of a CSP representing a configurable product, on a second level, we manage a constraint problem gathering all the active variables and the constraints pertaining to active elementary configurable products. This constraint problem is interactively modified by the user who expresses restrictions or relaxations over the domains of the variables. Restrictions and relaxations are handled throughout unary constraints. Because the user is free to relax a previous restriction, we have chosen a dynamic CSP representation of the problem [START_REF] Detcher | Belief maintenance in dynamic constraint networks[END_REF]. For us to guide the user toward a feasible product, the problem has to be kept consistent with the user choices. But the constraint problem can be significantly large (numerous variables and constraints), hence global consistency is often too costly to enforce, so we only enforce a level of local consistency. We have explored some of these levels and finally the good old arcconsistency [START_REF] Mackworth | Consistency in Networks of Relation[END_REF], Mohr and Henderson 1986[START_REF] Bessi~re | Arc Consistency and Arc Consistency Again[END_REF][START_REF] Debruyne | Arc-Consistency in Dynamic CSPs Is No More Prohibitive[END_REF] for the adaptation to dynamic CSP) has proven to be a valuable candidate. Our first experiments have shown little interest for stronger levels of consistency, except for enforcing singleton arc-consistency (Debruyne and Bessi~re 1997) the domain of the variables picked by the user, before letting him modify it.

Interaction between the two levels

The two previously described levels are tightly coupled; interaction between the two levels occurs through (i) the shared variables, i.e. the variables that appear in the CSPs of both problems; (ii) the change of activity state of object. Indeed, in order to keep the CSP as simple as possible, whenever a configurable product becomes active, the linked constraints are added, and are removed when it becomes inactive.

Conclusion ""

Configuration is becoming an important issue for companies' competitiveness. Previous research shows that the CSP framework is of interest when addressing the configuration problem, but as shown in section II this research does not succeed in taking into account all the specific requirements of configuration for industry. In terms of a solution we have provided a two-level approach to handle some of these requirements and to solve the configuration problem interaetively. This approach has been implemented within the Cam616on software suite, an interactive selling system from Access Productique. As previously mentioned, handling interactivity is a key issue in the configuration problem. Indeed, we need to provide easy to use software tools to people without product technical knowledge in order to let them achieve a complex configuration. The extreme case would be a webbased configurator for very complex products. Hence we need to work on providing contextual help to the user. This help could either be on the first level (activity of subcomponents) or on the second level (explanations about discarded values). We are currently exploring an approach based on the arc-consistency algorithm providing supports.

Acknowledgments

This work was granted by Access Productique (S.A.).

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Artificial Intelligence, 25-32. AAAI Press Mohr and Henderson 1986. Arc And Path Consistency Revisited, Artificial Intelligence 28:225-233, 1986. Sabin and Freuder, E. 1996. Configuration as Composite Constraint Satisfaction, Technical Report FS-96-03, Workshop on configuration. 28=36. AAAI Press.