Sarah Mcnicol

Karine Aillerie

Digital inequalities and social media: experiences of young people in Chile

Keywords: Social capital, Chile, Information-seeking, Social media, Digital divide, Social networking services Paper type -Research paper

Purpose -This paper aims to report the findings from a survey of secondary school students in Chile by exploring their use of social networking services for information-seeking purposes.

Design/methodology/approach -An online survey was distributed via Chile's Ministry of Education and 12,354 responses were received.

Findings -The results indicate that young people in Chile extensively use SNSs, but there are differences in the ways in which they use these services, specifically for information purposes. When considering school related activities, there are differences in the use of SNSs by students in different types of schools. Those in academic-focussed institutions are more likely to use SNSs for school-related information purposes and are more likely to publish most types of information on SNSs than their counterparts in vocational schools.

Research limitations/implications -The sample was self-selecting and excluded students without online access to the survey.

Practical implications -The findings indicate more needs to be done in schools serving lower socioeconomic communities to support students' use of SNSs for information-seeking, especially for academic purposes.

Social implications -The findings suggest that school-associated social capital may have a role in shaping students' use of SNSs for information and learning purposes and, potentially, in exacerbating digital inequalities.

Originality/value -The focus on the use of social media specifically for information-seeking distinguishes this research. The findings challenge possible assumptions about the links between social media use and social class and suggest that differences may be exacerbated by school practices.

Introduction

Many commentators have made the case that the internet tends to reinforce social inequalities rather than act as a leveller [START_REF] Golding | World-wide wedge: division and contradiction in the global information structure[END_REF][START_REF] Norris | Digital Divide: Civic Engagement, Information Poverty and the Internet Worldwide[END_REF][START_REF] Wei | Does the digital divide matter more? Comparing the effects of new media and old media use on the education-based knowledge gap[END_REF]. While there is no single conception of the term "digital divide", the majority of definitions consider some or all of the following themes: attitudes towards technology, access, skills and types of usage. Historically, basic access was seen as the key measure of inequality [START_REF] Foundation | Losing ground bit by bit: low-income communities in the information age[END_REF][START_REF] Strover | Rural Internet Connectivity[END_REF]. Over time, however, interest has moved away from access concerns to consider skills and the nature of internet use among different groups [START_REF] Dimaggio | Digital inequality: from unequal access to differentiated use[END_REF][START_REF] Zillien | Digital distinction: status-specific types of internet usage[END_REF][START_REF] Van Deursen | The digital divide shifts to differences in usage[END_REF]. As Schradie (2011, p. 146) argues, "digital inequality scholarship has expanded from a divide based simply on computer ownership to a range of inequalities in access and use of various digital technologies". Although a variety of social indicators, including gender, age and ethnicity, have been studied in relation to digital inequality issues, socio-economic status indicators are seen as one of the key predictors of internet usage. Several authors [START_REF] Zillien | Digital distinction: status-specific types of internet usage[END_REF][START_REF] Dimaggio | Digital inequality: from unequal access to differentiated use[END_REF] have argued that factors such as educational level, employment status and income have a significant impact on internet use, as people with higher socioeconomic status tend to use the internet more productively and for greater economic gain, even if they do not have better access than less privileged users. For example, [START_REF] Hargittai | Digital inequality: differences in young adults' use of the internet[END_REF] found that those with higher levels of education were more likely to use the internet for "capital-enhancing" activities such as seeking political or governmental information; exploring career opportunities; and accessing information about financial and health services. On the other hand, [START_REF] Van Deursen | The digital divide shifts to differences in usage[END_REF] found that, among users in The Netherlands, those with lower levels of education tended to focus their internet use on social interaction and gaming. Research focussing on young people has identified similar patterns. Hargittai and Walejko (2008, p. 241) report that, in the UK and the USA, children from higher socioeconomic backgrounds are more likely to experience educational gains from home computer and internet access. The authors suggest that this is owing to the fact that "exposure to experiences that increase participatory culture and digital literacy are unequally available to individuals regardless of their access to digital media". For example, students with at least one parent with a graduate degree are significantly more likely to create content than those without (247-8). Naturally, commentators have attempted to form explanations for these observed differences. For example, [START_REF] Dimaggio | Digital inequality: from unequal access to differentiated use[END_REF] emphasise the importance of social networks and cultural capital in relation to internet use. In this context, social capital can affect the extent to which people are exposed to new technologies and get assistance from friends and family to use them. [START_REF] Robinson | A taste for the necessary: a bourdieuian approach to digital inequality[END_REF] coined the term "information habitus" to describe how those who have less control over their internet access develop a "taste for the necessary", whist those with greater freedom developmore playful or creative approaches.

Digital inequalities and social media

As well as research into internet usage in broad terms, there have also been studies of differences in the use made of social media, which can be defined as "internet-based applications that [. . .] allow the creation and exchange of user-generated content" (Kaplan and Haenlein, 2010, p. 61). Blogging is one of the most heavily researched forms of social media. [START_REF] Hindman | The Myth of Digital Democracy[END_REF] indicates links between blogging and socio-economic class, for example, reporting that the majority of the most widely read blogs in the political arena are run by people who have attended an elite institution of higher education. At a more mundane level, Schradie (2011, p. 145) found that high school-educated Americans were less likely to blog than their college-educated counterparts. She identified a "digital production gap", which means "elite voices still dominate in the new digital commons". However, evidence regarding the links between social media and social class is not clear-cut. For instance, although they found gender and cultural differences, [START_REF] Davidson | Exploring young people's use of social networking sites and digital media in the internet safety context: a comparison of the UK and Bahrain[END_REF] reported little difference in the use of social media across social classes. Similarly, [START_REF] Chou | Social media use in the United States: implications for health communication[END_REF] found no substantial educational divides between bloggers and nonbloggers Considering social media as a whole may be misleading; it is possible that some social networking services (SNSs) are more closely associated with social class than others. For example, a survey in 2014 found that LinkedIn and Twitter were particularly popular among college-educated users and those with higher levels of household income, but this pattern was not seen for other sites including Facebook and Instagram [START_REF] Duncan | Demographics of key social networking platforms[END_REF]. Drawing on Bourdieu's ideas, boyd (2014, p.170) describes how teenagers differentiate sites such as MySpace and Facebook according to "taste", identifying them as "distinct cultural spaces and associating different types of people with each site". This is an important consideration, as Hargittai (2007, p. 122) cautions: [. . .] researchers should tread lightly when generalising from studies about the use of one SNS to the use of another such service because, whilst there are similarities between services, they can attract different populations and may encourage different types of use.

1.2 Social media use in Chile Social media are undoubtedly popular in Latin American countries; in June 2011, it was estimated that 114.5 million people in Latin America visited an SNS, representing 96 per cent of the entire online population in the region [START_REF] Seguic | Latin America's internet population grows 15 per cent in past year to 112 million people[END_REF]. It is estimated that Chile has 10.6 million active social media users, and the social media penetration rate of 61 per cent is the highest in the Americas (We Are Social, 2014). [START_REF] Seguic | Latin America's internet population grows 15 per cent in past year to 112 million people[END_REF] calculated that the average number of hours users spent on SNSs was 8.7 among Chileans, compared to a global average of 5.4 h. Among young adults (18-29-year-olds), an estimated 94 per cent are registered Facebook users and more than three-quarters visit the site at least once a day (School of Journalism UDP, 2013). Interestingly, [START_REF] Correa | Digital skills and social media use: how internet skills are related to different types of Facebook use among digital natives[END_REF] reports that young adults with lower levels of education use Facebook most frequently. While the impact of social media on political behaviour [START_REF] Valenzuela | Unpacking the use of social media for protest behaviour: the roles of information, opinion expression and activism[END_REF] and amongst university students [START_REF] Crespo | Motivación, consumo y apreciaciones de facebook por parte de jóvenes universitarios: el caso de la red UCSC Chile[END_REF] in Chile has been reported elsewhere, there has been little consideration of the use of social media among school students in Chile for information purposes. Thanks to the Enlaces programme [1], which has been running since the early 1990s, technology is more widely available in Chilean schools than in most South American countries. For example, in 2010, 92 per cent of Chilean schools had internet access compared to only 58 per cent in Argentina and 44 per cent in Brazil (OCDE, 2010). At 17.49, the average number of PCs with internet access in schools in Chile is considerably higher than the average for the continent of 11.0. Furthermore, around half of Chilean students have access to a PC in their home compared to the average for Latin America of just over one-third [START_REF] Román | Disponibilidad y uso de TIC en escuelas latinoamericanas: incidencia en el rendimiento escolar[END_REF]. However, divides still exist: while 42.3 per cent of Chilean students reported using a PC in school at least once a week, 27.1 per cent never did so. Furthermore, in Chile, as is the case elsewhere in Latin America, students in private schools and those in urban areas are most likely to have access to a PC [START_REF] Román | Disponibilidad y uso de TIC en escuelas latinoamericanas: incidencia en el rendimiento escolar[END_REF].

Inequality in the Chilean educational system

The inequality that exists within the Chilean education system has been widely reported. As the OECD (2013, p. 4) recognises, although levels of attainment have greatly improved over recent years, "equity remains an issue, particularly for socio-economically disadvantaged students" as more than 23 per cent of the difference in student performance can be attributed to socio-economic status. This compares to an average of 15 per cent across OECD countries. The OECD identifies school choice as one of the main factors hindering greater progress.

PISA statistics from 2009 show that a 15-year-old in Chile is less likely than their peers in other OECD countries to be in a school with students of different socio-economic status and academic performance (OECD, 2013). 1.3.1 School funding in Chile. Mujila (2012, p. 148) describes the "quasi-market in Chilean education" which developed during the 1980s as changes in the financing of schools were introduced, resulting in a new type of school: the "particular subvencionado". These semiprivate schools receive funding from the state, but are run by private entities and have greater autonomy than "municipal" schools, which are also state-funded, but run by local municipalities. In addition to these two types of state-funded schools, there are also private "particular pagado" schools that receive their funding from private sources. It is widely acknowledged that the type of funding arrangement of a school (its "dependencia") is highly correlated with the socio-economic status of its students. As [START_REF] Mujila | El cuasi-mercado educativo en Chile: desarrollo y consecuencias[END_REF] describes, students in private schools are generally from the upper-middle classes; those attending semi-private schools are from the lowermiddle classes; and students in municipal schools tend to be from working-class families. [START_REF] Elacqua | School choice in Chile: is it class or the classroom?[END_REF] report data from 2003 indicating that around 80 per cent of students fromthe two lowest socio-economic groups were enrolled in municipal schools. In contrast, 94 per cent of students from the highest socio-economic group attended private schools. Furthermore, most parents only considered schools with similar student demographics for their children.

Academic and vocational schools.

In addition to a divide based on school funding arrangements, there are also differences between vocational and academic secondary education (14-18 years) in Chile. In broad terms, humanista-científico (academic) education prepares students for higher education, while técnico-profesional (vocational) education prepares them for the world of work. There are also smaller numbers of other types of school, for example, those offering arts-based courses. Ministry of Education figures show that, in 2014, 38 per cent of state-funded secondary schools (966 out of 2,542) offered vocational education (as received via an email to the author). This option offers students more work-related learning, but less time is devoted to academic study, and the OECD (2013, p. 4) has noted the "challenging" transition students from this type of school can face when entering further education or the labour market. There are considerable differences in the performance of students enrolled in vocational schools compared to those in academic schools. When Farías and Carrasco (2012) explored these differences in performance, they suggested that teachers in vocational schools may have lower expectations of their students and that the students in these establishments may be less motivated, have lower expectations and enjoy less family support than those in academic schools.

Methods

A short online survey was conducted to capture data from secondary school students in Chile on their use of social media, in particular for information-seeking purposes (rather than for more general communication uses). Relatively few previous studies have focused on the use of social media for information-seeking among secondary school-age students [START_REF] Grant | Young peoples' relationships with online marketing practices: an intrusion too far?[END_REF][START_REF] Willemse | James -Jeunes, activités, médias: enquête Suisse[END_REF] being among the few examples as discussed in detail in [START_REF] Aillerie | Are social networking sites information sources? Informational purposes of high-school students in using SNSs[END_REF]. Our research sought to answer two research questions (RQs): RQ1. Do secondary school students use SNSs as information sources? If so, do they use social networking services (SNSs) as information sources for everyday life topics alone, or as information sources for academic purposes as well? RQ2. What are students' motivations for using SNSs specifically as information sources?

The types of information uses students were asked about in our survey included not only tasks directly related to school activities but also information sought for non-academic purposes, for example, informal learning and social or political activities. The survey, designed using Google Forms, was based on companion surveys which were conducted in French, English and Danish in Spring 2015 and the results are reported elsewhere [START_REF] Aillerie | Are social networking sites information sources? Informational purposes of high-school students in using SNSs[END_REF]. The Chilean version was translated into Spanish and questions added, or adapted, to collect data on the types of schools attended by students (as described above). The online survey was available between 3 March and 16 April 2015. It was promoted to schools via the Minedu CRA (Ministry of Education, Learning Resource Centre) team's Facebook group (Bibliotecas Escolares CRA), bi-monthly bulletin and the webpage and by sending bulk emails. The announcement asked librarians and teachers to encourage their students to complete the survey. While this method of survey distribution resulted in a selfselecting sample, both in terms of librarians or teachers who chose to promote it and students who completed the survey, it allowed us to easily reach a large number of students across the country through established communication methods that schools would trust. There were 12,354 responses after 59 incomplete responses had been removed. The data were analysed in SPSS to produce descriptive statistics, and chi-square analysis was carried out to explore possible differences between responses from students in the various categories of school. In total, 53.9 per cent responses were from female students and 46.1 per cent from male students. The median age was 15 years. The majority of students, 61.2 per cent, were from academic schools; 33.0 per cent were from vocational establishments. In terms of school funding arrangements, the majority of responses, 70.3 per cent, were from students in semiprivate schools; 27.5 per cent were studying in municipal schools; and just 0.9 per cent in private establishments. Table I shows a breakdown of responses from students at various types of schools. It is worth noting that the proportion of responses from students at private schools was notably lower than might have been expected (0.9 per cent compared to 12.9 per cent nationally), but this was not surprising, as Minedu has limited contact with these schools. The proportion of semi-private schools was correspondingly higher than the national figure (70.3 per cent compared to 57.2 per cent nationally), while the proportion responding from municipal schools was identical to the national figure for schools with this funding model (27.5 per cent) (Ministerio de Educación de Chile, Centro de Estudios, 2015).

3. Findings 3.1 Use of social networking services When students were asked which SNSs they had accounts for, the most common response was Facebook (93.8 per cent), followed by YouTube (59.3 per cent), Instagram (52.2 per cent), Google+ (52.0 per cent) and WhatsApp (51.2 per cent). In contrast, students were the least likely to have accounts for Flickr (2.6 per cent), Vine (6.6 per cent) and Snapchat (12.2 per cent), as shown in Figure 1. In addition to the options provided by the researchers, SNSs mentioned by more than ten students were: Skype (93), Wattpad (89), We Heart It (57), Pinterest (36), Line (26), DeviantArt (17), Steam (14) and Taringa (14). The funding arrangements of students' schools did not appear to be related to the SNSs students had accounts for. However, there were differences to be seen between students from academic schools and vocational schools. Students from academic schools were more likely to have accounts for Instagram, Twitter, Googleþ, Tumblr, Snapchat, YouTube and Vine (p < 0.01 in each case). Of course, merely having an account does not necessarily mean students actually use a service regularly. As shown in Figure 1, Facebook was, overwhelmingly, the most commonly used SNS (75.3 per cent said they used it regularly), followed byWhatsApp (48.5 per cent), Instagram (26.2 per cent) and YouTube (25.0 per cent). The least regularly used SNSs were Flickr (0.2 per cent), Vine (0.8 per cent) and Ask.fm (1.9 per cent).

Using SNSs for information purposes

In this research, we were particularly interested in students' use of SNSs for informationseeking, rather than for more general purposes. Almost all students surveyed used SNSs specifically for information purposes and the majority did so on a regular basis. More than two-thirds of students (70.7 per cent) said they used SNS to seek information regularly and 23.2 per cent did so occasionally. Only 6.1 per cent said they rarely or never used SNS to seek information. When asked which SNSs they used for information-seeking specifically, there were noticeable differences from the types of services students used more generally, as shown in Figure 1. In this context, Wikipedia was the site used most regularly (20.7 per cent), followed by YouTube (11.5 per cent) and Facebook (10.9 per cent). All other SNSs were used regularly to search for information by less than 10 per cent of students.

As shown in Figure 2, information about cultural events was the most common type of information students looked for on SNSs (49.2 per cent). This was followed by information related to friends (37.7 per cent) and information about games (34.7 per cent). Practical information (e.g. transport or weather) (17.5 per cent) was the least commonly sought type of information. In broad terms, therefore, information about social activities and hobbies was mentioned most frequently; what [START_REF] Hargittai | Digital inequality: differences in young adults' use of the internet[END_REF] term "capital-enhancing" activities, such as news or health information, were less common. The use of SNSs for tasks directly related to education ranged quite widely. Almost one third of students (31.1 per cent) said they used SNSs to find information for a task at the direction of a teacher, making this the fourth most common use of SNSs for information purposes overall. However, fewer students used SNS for independent learning: 20.9 per cent said they had used SNSs to find additional information about topics taught in class (extension of a lesson) and 18.0 per cent used SNSs to find information for a school project independently (i.e. not explicitly directed teacher). In addition, 23.3 per cent used SNSs to search for information related to educational and vocational guidance. Notably, there was a significant difference between the use of SNSs for school-related tasks among students from schools with different funding arrangements. Students from semi-private schools were most likely to use SNS as an extension of a lesson (p < 0.01) and for career information (p < 0.05), and those from private or semi-private schools were more likely to use SNSs to find information at the request of a teacher (p < 0.05). Interestingly, when non-school uses of SNSs were compared, there were no significant differences between schools with different funding models; students' social and practical uses of SNSs did not appear to vary depending on how their school was funded. There were also significant differences between the students from academic and vocational schools in their use of SNSs as an extension of a lesson; for information at the request of a teacher; for independent projects; and for careers information and guidance. In each case, students from academic schools were most likely to use SNSs (p < 0.01). Once more, these differences were not seen when social and practical information (non-school) uses of SNSs were compared, with the exception of information about friends.

Publishing information on SNSs

Students surveyed were also asked about their information-publishing habits on SNSs. Although more than one-quarter (28.4 per cent) said they did not publish any information on SNSs, over half (53.3 per cent) published comments and opinions. Publishing personal photos or videos was also a widespread activity (43.8 per cent). Around one-quarter republished information found elsewhere (24.3 per cent) and approximately the same proportion published personal texts (23.7 per cent). However, publishing academic information was less common; just 11.7 per cent of students said they published academic information, for example, on class Facebook groups. There were statistically significant differences between students from schools with different funding arrangements in terms of their publishing habits. Those from semi-private schools were most likely to publish personal texts, photographs and videos, academic information and republished information, while those from municipal schools were most likely to publish comments and opinions (p < 0.01 in each case). Students from private schools were least likely to publish all types of information (p < 0.01). There were also statistically significant differences between the publishing habits of students from academic and vocational schools, with those from academic schools being most likely to publish photographs and videos, academic information and republished information (p < 0.01 in each case).

Discussion

It is not unexpected to find that young people in Chile extensively use social media given the high level of engagement with social media in the country and the provision of digital technologies in schools. However, this research suggests that, despite good levels of access, there are notable differences in the ways in which SNSs are used, especially for informationseeking purposes. In particular, there appear to be differences between types of schools that characteristically attract students from different socio-economic backgrounds. To some extent, this might be expected, as the tendency for higher status individuals to make greater use of the internet for information purposes has been widely documented [START_REF] Notten | Research note: digital divide across borders[END_REF][START_REF] Peter | Adolescents' internet use[END_REF]. As Zillien and Hargittai (2009, p. 287) argue, "those already in more privileged positions are reaping the benefits of their time spent online more than users from lower socioeconomic backgrounds". In the case of Chile, Correa (2015, p. 9) found that "more educated and skilful individuals tend to use Facebook in more expressive and potentially beneficial ways than lower educated and less skilful people". In this survey, there were certainly differences in the way that students from different types of schools report interacting with SNSs for information purposes. However, our findings diverge from those found in previous research because, in their use of SNSs for social, political or practical information, or for informal learning (e.g. news, cultural information, health, games), there were few evident differences between the behaviours of students from different types of school. Among young people in Chile, therefore, the patterns commonly reported from research into adult online behaviours [START_REF] Hargittai | Digital inequality: differences in young adults' use of the internet[END_REF][START_REF] Van Deursen | The digital divide shifts to differences in usage[END_REF] are not borne out; typically higher-class students from academic and private or semi-private schools are no more likely to use SNSs for "capital enhancing" activities than their counterparts from schools largely catering for those from lower socio-economic classes. When we turn to school-directed activities, however, it is a different story. When considering school-related information-seeking specifically, differences become apparent. The use of SNSs for teacher-directed activities, independent projects, lesson extension activities and career information are all more likely among students from academic schools than among those studying a vocational education. Students from academic schools were also more likely to publish more complex forms of information, including academic information. This suggests that the methods of teaching and expectations placed on students in academic schools may do more to encourage the use of SNSs for educational purposes, thereby supporting the development of students' information seeking and digital literacy skills. So, despite the fact that there may be little difference in their social and informal use of SNSs for informationseeking, within an educational context, students from academically focussed schools are developing skills and habits which may allow them to make greater use of technology for "capital-enhancing" activities in later life. Our findings suggest that differences in social media use are not simply a case of inequality between social classes. Rather, the type of education a student receives, and perhaps, the expectations and support that accompany that are important factors. [START_REF] Bourdieu | Distinction[END_REF] notion of habitus is of particular relevance here. Habitus can be described as: [. . .] the way society becomes deposited in persons in the form of lasting dispositions, or trained capacities and structured propensities to think, feel and act in determinant ways, which then guide them" (Wacquant 2005, p. 316). Zillien and Hargittai (2009, p. 289) advocate the use of this notion to describe "something status-related" that determines internet use in addition to factors such as age, gender, access, experience or interest. The role of social capital in structuring the diffusion of new technologies has been discussed by a number of authors [START_REF] Rogers | Diffusion of Innovations[END_REF][START_REF] Dimaggio | Information inequality and network externalities: a comparative study of the diffusion of television and the internet[END_REF]. For example, social capital can affect the extent to which people are exposed to new technologies and get assistance from friends and family to use them. According to Chen (2013), peer influence is strongly associated with internet use among high school students and affects technology adoption via modelling, encouraging and facilitating. Exploring the use of social media specifically, boyd (2014, p. 171) argues that: As teens turn to social media to connect with their friends, they consistently reproduce networks that reflect both the segregated realities of everyday life and the social and economic inequalities that exist within their broader peer networks It is, therefore, noteworthy that the only difference to be found in non-academic uses of SNSs for information purposes was to find information about friends. While further research is needed to investigate this possibility, the findings of this survey suggest that social capital, transmitted via peers, teachers and the wider school community, may have a role in shaping students' use of SNSs for information purposes, not merely perpetuating long-standing class divisions, but exacerbating them. The findings of this research are significant, not only for Chilean educators but also for those in any country which has a similar divide between academic and vocational school provision and/or school funding models. Even in countries, or localities, which do not divide schools into academic and vocational categories, there may be subtler divisions that divide students according to social class, such as the use of "catchment areas" in the UK and elsewhere to define the geographical area fromwhich students are eligible to attend a school. This means that the socio-economic composition of schools becomes relatively homogenous, with "higher SES pupils being more likely to be accepted into (nearer) more advantaged schools" (Burgess et al., 2011, p. 544). These findings indicate that more needs to be done by librarians and teachers in schools serving lower socioeconomic communities to support students' use of SNSs for information seeking purposes, especially in academic contexts. This may involve altering the expectations placed on students by teachers and parents, as well as working to address student motivation and expectations for the future; raising awareness of the role that information obtained from SNSs, as well as elsewhere, can play in shaping their lives; and ensuring they have not only the opportunity to access SNSs but also the social capital to use them in the most productive ways. This is likely to require formal training opportunities, as well as informal idea sharing, amongst librarians and teachers to develop new approaches for the use of social media for learning purposes. The following activities are designed to support the use of social media for learning and they illustrate the types of activities librarians or teaching staff might consider introducing to promote more effective use of SNSs for information-seeking in school settings. Crucially, these activities build on students' existing uses of social media and show how the types of information available through social media can have a practical impact on young people's lives. In the first example, [START_REF] Crowley | New media and critical literacy in secondary schools[END_REF] describes the use of vandalised Wikipedia pages and hoax YouTube videos to introduce young people to the skills they need to evaluate and critique information they find on social media. As he points out, a traditional algorithmic approach is not well-suited to the evaluation of social media sites where issues of bias and reliability are more nuanced and complex. The approach he outlines places emphasis on the environment in which social media is created as much as the media itself. In a similar vein, [START_REF] Bellin | Teaching the skills to question: a credit-course approach to critical information literacy[END_REF] describe a course in which students create their own YouTube video news reports on topics of interest to them then reflect on these as a class. Finally, [START_REF] Jones | Curricular and extra-curricular opportunities to engage school students in critical literacy in England[END_REF] describes how a student engaged with the online attacks that women face by analysing the language, narratives and modes of address used, then created a video piece appealing for women to claim the space of the internet and use it to develop a strong voice. These examples demonstrate how, through creative approaches, librarians might make changes to the ways in which SNSs are used in schools, which can, in turn, contribute to raising student expectations, increasing awareness of the role information can play, both in educational contexts and in everyday life and developing the social capital of all students. Note 1. www.enlaces.cl


Oussama Ennafii

Arnaud Le Bris

Florent Lafarge

Clément Mallet

SCALABLE EVALUATION OF 3D CITY MODELS

Keywords: 3D, urban, buildings, quality, classification, error detection, geospatial imagery, Very High Resolution, scalability, transferability, representativeness

The generation of 3D building models from Very High Resolution geospatial data is now an automatized procedure. However, urban areas are very complex and practitioners still have to visually assess the correctness of these models and detect reconstruction errors. We proposed an approach for automatically evaluating the quality of 3D building models. It is cast as a supervised classification task based on a hierarchical taxonomy and multimodal handcrafted features (building geometry, optical images, height data). In this paper, we evaluate how the urban area composition impacts prediction transferability and scalability of our framework to unseen scenes. This allows to define minimal feature and training sets for a problem where no benchmark data has been released so far.

INTRODUCTION

3D urban models have a wide range of applications covering in particular critical domains with significant societal challenges. 3D city modeling has therefore been deeply explored in the photogrammetric, GIS, computer vision, and computer graphics literature with an emphasis on compactness, full automation, robustness to acquisition constraints, scalability, and, inevitably, quality [START_REF] Lafarge | Creating large-scale city models from 3D-point clouds: a robust approach with hybrid representation[END_REF][START_REF] Cabezas | Semanticallyaware aerial reconstruction from multi-modal data[END_REF][START_REF] Zeng | Neural procedural reconstruction for residential buildings[END_REF]. The problem remains partly unsolved [START_REF] Musialski | A survey of urban reconstruction[END_REF][START_REF] Rottensteiner | Results of the ISPRS benchmark on urban object detection and 3D building reconstruction[END_REF], since current algorithms lack of generalization capacity. They fail handling the significant heterogeneity of urban landscapes [START_REF] Sester | Theme issue "quality, scale and analysis aspects of urban city models[END_REF]. Human intervention is needed as a post-processing refinement and correction step, which is highly time-consuming (individual visual inspection of buildings). Consequently, automatizing the last step remains a critical step. Surprisingly, it has been barely investigated in the literature [START_REF] Kaartinen | Accuracy of 3d city models: EuroSDR comparison[END_REF][START_REF] Boudet | A supervised classification approach towards quality self-diagnosis of 3D building models using digital aerial imagery[END_REF][START_REF] Michelin | Quality evaluation of 3D city building models with automatic error diagnosis[END_REF][START_REF] Xiong | A graph edit dictionary for correcting errors in roof topology graphs reconstructed from point clouds[END_REF]. In [START_REF] Ennafii | The necessary yet complex evaluation of 3D city models : a semantic approach[END_REF], we proposed a semantic evaluation framework in which building semantics is taken into account through the detection and categorization of modeling errors at the facet level for each 3D building. Our solution is independent from a given urban area, the Level of Details (LOD) of buildings, and the 3D modeling method. The problem is formulated as a supervised classification problem which predicts all errors affecting the building model. It is based on (i) a taxonomy of errors, hierarchical, adapted to all LODs, and independent from input models, and (ii) a multimodal handcrafted baseline of features that are extracted from the model itself, as well as from Very High Resolution external data (optical images and Digital Surface Models -DSM). This paper focuses on the evaluation of the scalability of our framework. When dealing with non trivial remote sensing problems with limited training and testing sets, two major pitfalls exist: overfitting for a given area and divergent conclusions for various areas. This prevents from drawing strong conclusions of large applicability on the problem at stake. Here, using three distinct manually annotated urban areas in France, we analyze the transferability, generalization, and representativeness capacities of the proposed feature and training sets for all errors in the taxonomy. Eventually, this allows to define suitable feature and training sets for a problem where no benchmark data has been released so far.

SCALABILITY ANALYSIS

The evaluation framework

Our 3D building model evaluation framework consists in detecting errors, for every building, according to a hierarchical taxonomy of 9 atomic errors [START_REF] Ennafii | The necessary yet complex evaluation of 3D city models : a semantic approach[END_REF]. These errors correspond to two distinct levels:

• The building level: over segmentation (BOS), under segmentation (BUS), imprecise footprint borders (BIB), inaccurate footprint topology (BIT).

• The facet level: over segmentation (FOS), under segmentation (FUS), imprecise borders (FIB), inaccurate topology (FIT), imprecise geometry (FIG).

We disentangle fidelity and modeling errors and can evaluate LOD-0, 1, and 2 models. Error detection is performed with a supervised Random Forest classifier at three different finesse levels (0: qualifiable/non qualifiable -1: valid/erroneous -2: facet/building error -3: 9 atomic errors). The process is based on a set of 60 features stemming from 3 different sources (20 each): the geometry of the model itself (e.g., angle between adjacent facets), a VHR optical image (e.g., matching scores between image and building contours), and a Digital Surface Model (based on the histogram of the height residuals with the model). More details are available in [START_REF] Ennafii | The necessary yet complex evaluation of 3D city models : a semantic approach[END_REF],

where one can see that all sources contribute equally, even if geometric features suffice to reach high accuracies.

Strategy

Experiments shown that the scene composition can affect greatly model error detection. This fact motivates studying training the classifier and testing prediction on different scenes. The goal is to prove the resilience of the prediction to unseen urban scenes. As the annotation process requires a lot of effort, this trait is crucial to guarantee the scalability of this method. Different configurations are evaluated (Figure 1).

• Transferability: we test how transferable are the learned classifiers from one scene to another. We train on area A i and test on another one A j . We will denote each transferability experiment by the couple (A i , A j ) or by A i → A j . n(n -1)/2 transferability couples are therefore possible, n being the number of areas.

• Generalization: we try to find out how omitting one area from the training set affects the results on the same area. We also aim to confirm the outcome of the transferability experiments. Experiments that fuse all areas except A i (

∀j =i
A j ) for training and test on A i are noted by the couple (

∀j =i A j , A i ) or by ∀j =i A j → A i .
There are n possibilities.

• Representativeness: the objective is to find out, when mixing all labelled buildings from all n datasets, which amount of training data is required for a stable outcome, as well as how such ratio affects the test results if trained only on one type of cities. Different ratios between 20% and 70% are evaluated.

F-score metrics per error are selected for the evaluation of the various configurations. These experiments are also compared with the results obtained for each area (training+testing) with various feature sets [START_REF] Ennafii | The necessary yet complex evaluation of 3D city models : a semantic approach[END_REF]: 3D model geometry (Geom.), VHR optical image (Im.), and DSM (Hei.). For each error and problem, we compute the mean and the standard deviation of the F-score according to several possible feature sets and evaluate which contributes the most to the detection of the error. These are: Geom., Geom. ∪ Hei., Geom. ∪ Im., and All. Results are compared with a baseline provided in [START_REF] Ennafii | The necessary yet complex evaluation of 3D city models : a semantic approach[END_REF].

denser urban setting with lower building diversity. In Paris-13, high towers, with flat roof, coexist with Haussmann style buildings that typically exhibit highly fragmented roofs. The Elancourt (resp. Nantes and Paris-13) scene contains 2,009 (resp. 748 and 478) annotated building models. The spatial resolution of the DSM and the orthorectified images is 6 cm while it is 10 cm for the two other sets. 3D models were generated using [START_REF] Durupt | Automatic building reconstruction from a Digital Elevation Model and cadastral data: an operational approach[END_REF], fed with existing building footprints and aerial VHR multi-view DSMs. The algorithm simulates possible LOD-2 roof structures from a predefined grammar with facets satisfying some geometric constraints. The best configuration is selected using a scoring system on the extrapolated roofs. Finally, orthogonal building façades connect the optimal roof to the ground. This method is adapted to roof types of low complexity and favors symmetrical models (residential areas). It has been selected to ensure a varying error rate for the three areas of interest.

EXPERIMENTS

Main results are reported in Figure 1 and Table 1.

Transferability

Three datasets lead to the evaluation of six transferability cases. In Figure 1a, one can see two distinct behaviours: stability across datasets and high fluctuations. In general, facet errors are more resilient and often yield better results than building errors. Fluctuations in F-score can be mainly noticed for the Nantes → Elancourt and Paris-13 → Nantes cases: FUS and FIB are better detected while a significant drop in performance exists for BOS (-30%). This stems from the limited diversity and size of training sets for Nantes and Paris-13. This confirms the intuitive idea that dense urban area scenes are more helpful with LOD-1∪0 errors and topological ones (FIT). Table 1 first shows that training on the testing area obviously leads to the best results, especially for building errors, even if the decrease in accuracy remains satisfactory in a large majority (∼ 10%). Elancourt, with more heterogeneous facets, is pivotal for the facet errors (FUS, FIB). Nantes provides the most effective training set for building errors. Secondly, contrarily to the ablation study conducted in [START_REF] Ennafii | The necessary yet complex evaluation of 3D city models : a semantic approach[END_REF], imagebased features and, with a lower impact, height attributes are often decisive in this experimental study. The geometry of the 3D model no longer suffices and remote sensing data is mandatory for transfer learning.

Generalization

Concerning the stability of the F-score values, similar conclusions to the transferability study can be drawn. Again, the framework performs better for the facet errors than the building ones in terms of generalization. Main decrease in accuracy (-25%) can be noticed for BOS and BUS errors when integrating Elancourt training data. Such a discrepancy in test scores between urban scenes proves the complementarity between the different datasets for most labels: dense city centers (Nantes, Paris-13) are really helpful for building errors and LOD1∪0, while residential areas with a large diversity and simplicity in roof types are particularly tailored as training sets for facet errors. Similarly, Table 1 shows that better results are still obtained when predicting errors on the training area. Few improve-ments are noticed, namely for detecting the inaccurate footprint topology (BIT), facet imprecise borders (FIB), and under-segmentation (FUS). Again, the composition of the urban scene has a significant impact on such a variation, again promoting the necessity of creating hybrid training sets capturing the geographical diversity of urban environments. Eventually, similarly to the previous experimental setting, remote sensing features have a major role in order to get the best scores. In particular, VHR optical images and their high frequencies (contours) are highly helpful for inner roof discrepancies (BUS, BIB, FUS, FIB We can finally notice less variance in F-score per experiment.

The variance vanishes with a more diverse dataset even if it is still larger than the variance in the ablation study [START_REF] Ennafii | The necessary yet complex evaluation of 3D city models : a semantic approach[END_REF]. No significant variation can be noticed when changing the feature set (Geom., Geom. ∪ Im., Geom. ∪ Hei., All). This explains why these experiments are not displayed in Table 1.

CONCLUSION

In this paper, we satisfactorily evaluated the scalability capacity of our 3D building evaluation framework over three distinct urban landscapes. Three dimensions of the problem were examined, namely transferability, generalization, and representativeness. The results first show that training samples stemming from very diverse urban environments are required to efficiently scale up this classification pipeline and detect errors with confusion close to the best results per area. In such a context, a limited number of samples is sufficient. Such findings allow to define a suitable training sample strategy in the future, especially in a context where fine-grained manual annotation of 3D data is complex. Secondly, experiments proved that multimodal remote sensing data is required for scalability purposes, while 3D building geometry was sufficient for a single area analysis. The next step consists in benchmarking major 3D city modelling techniques over various urban areas.

1 A 2 A 3 RepresentativenessFig. 1 .

 1231 Fig.1. Three-fold scalability analysis of our 3D building model evaluation framework. A i indicates the area of interest. Arrow origins and targets give information about which area(s) is(are) considered as training and test sets, respectively. Results are compared with a baseline provided in[START_REF] Ennafii | The necessary yet complex evaluation of 3D city models : a semantic approach[END_REF].

Fig. 2 .

 2 Fig.2. F-score mean and standard deviation values for the various tested feature sets for the three case studies. Experiments are performed for the nine atomic errors. B ** and F ** correspond to building and facet errors, respectively. El., Na., P13 correspond to the Elancourt, Nantes, and Paris-13 datasets, respectively.

Table 1 .

 1 ). Conversely, the Digital Surface Model is needed for outer and coarse errors (BOS,BIT, FIG). Evolution of the F-score value, for each error, between each tested configuration and the best result per area[START_REF] Ennafii | The necessary yet complex evaluation of 3D city models : a semantic approach[END_REF]. Feature sets having a significant impact on the classification results are mentioned. Otherwise, Geom. Im., and Hei. contribute equally. The color indicates the magnitude: : [-45, -35%[-: [-35, -25%[ -: [-25, 15%[-: [-15, 5%[ -: [-5, 5%[-: [5, 15%[ -: [15, 25%] -: statistics cannot be computed.

	4.3. Representativeness
	Figure 1c shows (i) most of the time superior performance
	in error detection than the previous studies, and (ii) the ex-
	treme stability of all errors across different split ratios. This
	first indicates that merging training samples for three distinct
	urban environments is the most suitable solution for a rele-
	vant training set, as already proved in Sections 4.1 and 4.2.
	Better results are noticed for the errors BOS, BUS and FUS.
	Such errors correspond to topological issues within building
	roofs. They therefore require a large diversity of training sam-
	ples in order to be correctly retrieved. Secondly, scalability
	in such conditions is ensured since no matter how small the
	training set is. No standard logarithmic behaviour can be no-
	ticed: 20% of the full labels are sufficient to retrieve all errors
	with an accuracy similar to training and predicting on a single
	area.


Boustany, J S Kurbanoğlu

Karine Aillerie
email: karine.aillerie@reseau-canope.fr

Anne Lehmans
email: anne.lehmans@u-bordeaux.fr

Anne Cordier
email: anne.cordier@univ-rouen.fr

Information Literacy in the Workplace

Keywords: transliteracy, information literacy, social interactions, community of practice, high-school

Information literacy has long been considered an important aspect in school, as well as in the workplace. Teenagers are the first group affected by requirements based on information skills. Transliteracy occurs as a relevant concept to understand these information practices. Indeed, a holistic approach is needed in order to take into account the multiplicity of contexts of uses and interactions. The resarch work described here proceeds from a program funded by the French national research agency (ANR Translit 2013-2016) focusing on how high-school students (15-16 years old) manage information with all the available media and tools, individually as well as collectively. Based on ethnographic methodology, the study was carried out between November 2013 and March 2015, in five French high schools during specific learning project based activities. Findings demonstrate that activities and knowledge management on the school workplace must take into consideration complex information skills crossing personal competencies, representations, and self-esteem on one hand, school requirements and context on the other; complex social interactions during information activities; postures and spaces encouraging horizontal learning processes between teachers and students in order to build a community of practice. Our results highlight what is directly visible and what remains implicit. They are likely to be useful for teachers as well decision-makers when designing learning scenarios and guidelines or curricula.

Introduction

In the 21st century, the skills required to be successful at school as well as in the workplace involve a high number of proficiencies. These skills include information seeking and problem solving strategies, a posteriori validation of information and critical thinking, social skills and collaboration, participation and creativity [START_REF] Voogt | A comparative analysis of international frameworks for 21st century competences: Implications for national curriculum policies[END_REF].

Teenagers are the first to be affected by these requirements. "Complex and fascinating" [START_REF] Boyd | It's complicated: the social lives on networked teens[END_REF] and deeply heterogeneous, their individual information practices beg questions. Far from the "digital natives" myth, their uses are multifaceted, distributed through juvenile socialization, daily activities, and educational requirements among others [START_REF] Cordier | Grandir Connectés : les adolescents et la recherche d'information[END_REF]. Transliteracy is found to be relevant in order to understand these information practices. As such this approach joins the theoretical and methodological contributions to a renovated definition of information literacy according to the fast-changing information world and the real practices of users in different settings.

Transliteracy was initially defined by Sue Thomas and colleagues [START_REF] Thomas | Transliteracy: Crossing divides[END_REF] as "the ability to read, write and interact across a range of platforms, tools and media from signing and orality through handwriting, print, TV, radio and film, to digital social networks". In a research project funded by the French National Research Agency, which took place in France from 2012 to 2016, we adopted a more complex definition for this notion of transliteracy. We included "information culture" in context, identifying situations of literacies, media and devices transfers. We analyzed information activity on a transliteracy based approach, while taking into account the social dimension and interactions between individuals. Finally, the researchers involved sought to highlight new forms of "information grammar" [START_REF] Chervel | Histoire de la grammaire scolaire[END_REF], transforming fragmented social knowledge into learning potential.

For this contribution, we choose to focus on data collected on the school grounds investigated in this project: five French high schools (15-16 years old students), from four different French areas, during specific learning project-based activities (10th grade, five classes of 30 pupils each). Relying on ethnographic methodology, we studied how students manage information with all the available media and tools, individually as well as collectively.

Theoretical and methodological framework

Five grounds have been investigated in senior and vocational high schools, over three years and for several weeks (2 -18) of observation of dedicated information research activities. During specific educational activities, students (15-16 years old) were required to collectively (by groups of 3 -4 members) produce digital outputs such as blogs, videos, travel diaries, slideshows. We aimed to take into account the "social thickness of in progress practices" [START_REF] Jeanneret | Lire, écrire, récrire ? Paris[END_REF] and then to holistically consider students' information practices and interactions, considering that Transliteracy necessarily grows within communities [START_REF] Liquète | Can one speak of an "Information Transliteracy"?[END_REF]. According to Liquète [START_REF] Liquète | Can one speak of an "Information Transliteracy"?[END_REF], the "trans" prefix means in the same time transversal (across different fields of knowledge), and transformation, from uses and practices to knowledge. Thus we have adopted an ecological approach in order to emphasize the role of global context (media and devices available, time and locations where the work took place, collective organizations, teachers' requirements and monitoring) in which one builds its relation to information. On the basis of the "situated" and "distributed" cognition approach [START_REF] Conein | Action située et cognition : le savoir en place[END_REF] [9], we aimed to take into account students and teachers' real uses and their representations. To embed this question of contexts, a multidimensional protocol was set up based on an ethnographic observation involving cross-methodologies: application of an observation grid common to all the fields of investigation, audio recording of the observed situations, pictures, collection of traces (e.g. pupils' productions, drafts and organizational documents, roadmaps provided by teachers, discussions on Facebook, online collaborative documents), students and teachers' interviews. Researchers, alone or in pairs, conducted non-participatory observations, kept a journal of research and carried out flexible exploratory interviews [START_REF] Vermersch | L'entretien d'explicitation enformation initiale et continue[END_REF] throughout the observed activity, in order to better understand actors' decisions at the moment.

Regarding the elements of observation, each researcher focused mainly on the context of action (dedicated working time, extensions outside the observed situation), the distribution of work within the groups, the individual as well as collective ways to search for information, interactions between pupils, pupils and teachers and between teachers, assessment criteria, the mobilization of various media and tools and moments of transition from one to another. During the observations, we moved regularly from a broad perspective to a narrow one, focusing on a single group, activity or interaction, and then returning to a view of the overall situation [START_REF] Grosjean | Étudier la dimension sensible des savoirs produits en contexte de travail[END_REF].

Key results in analyzing and processing information from a Transliteracy-based perspective

Spaces as a framework for interactions

Different school contexts were investigated. High-school libraries appeared to be a particularly legitimate and legitimating space for new forms of interactions and interdisciplinarity activities. Teachers and pupils expressed the feeling of being empowered within this specific teaching and learning place, building relationships with each others and working differently than in a regular classroom. A student explained: "When we are in the school library, we work all together, we exchange much more about what we do and how we do it". Other places at school could have been investigated as well (corridors or self-access rooms for instance). We have also observed horizontal relationships between pupils and teachers, who were satisfied to "learn beside and sometimes from their pupils", as witnessed by an English teacher.

It could have been assumed that the computer rooms would have been also favored by the actors, regarding digital projects. In fact, the interactions appeared to be impeded there: the inflexible organization arrangement of this kind of places does not favor multi-layouts and group work (space occupied by a computer on a narrow desktop, layout of computers in blocks, for instance), accentuating the division of labor.

In an observation carried out on a school trip abroad, we were especially able to measure the need to take into account the porosities between different contexts in informational situations. The school space extended into the social space when the school librarian precisely invited the students to collect information all over the city, involving the use of personal devices such as mobile phones or tablets. Thus, "intermediate spaces" [START_REF] Cottier | Le lycée à l'ère numérique: usages et recomposition des acteurs[END_REF] between school and personal life, face-to-face as well as remote, can support transliteral practices. Moreover, we have been able to observe, even within activities located at school, a strong externalization of interactions among students, especially through the uses of social networking sites and online collaborative tools. Those are pretty much compatible with regulation of group work and the coordination of tasks.

The complexity of collective organizations

There is a significant difference among teachers depending on their teaching profiles. There are those who assimilate group work with independence and "non-intervention", and those -often school librarians -who view these kinds of projects as an opportunity to promote information literacy activity as a priority. There is, however, a general consensus that there is a need for teacher's attitudes to change.

Reduced interventions could be used to encourage interactions among pupils as well as to enhance skills acquired out of school. We have actually observed that teachers mostly allowed groups to organize themselves as they could. This leads to a division of tasks that is carried out according to the media types (e.g. one student searching on the Web, another searching on the library database, another consulting dictionaries, etc.). Transliteracy is therefore not spontaneous, far from it. On the other hand, teachers' monitoring of students' activity is always carried out by the setting up of "boundary objects" [START_REF] Star | Institutionnal ecology, 'Translations', and Boundary objects: amateurs and professionals on Berkeley's museum of vertrebate zoologie[END_REF] such as roadmaps, logbooks or even tutorials, which can be considered as "documents for action" [START_REF] Dalbin | Documents en action dans une organisation : des négociations à plusieurs niveaux[END_REF].

It is moreover noticeable that an essential factor for activity regulation is the identification by the pupils themselves of their own expertise. For example, a storyboard was spontaneously produced by the group members in order to organize the tasks according to the skills which are individually assigned (bibliography, technical aspects, knowledge organization). A social circulation of the expertise was thus observed among students, who constantly verbalized their actions. As such, social networking sites and online collaborative tools play a great role in collective organizations, especially outside school time as mentioned above. As a result, students tend somehow to confuse the tools used with the organization itself. For instance, "we did a Google doc, Sir!" answered a student when a teacher asked how the group implemented the organization.

Interactions, skills and knowledge

The outputs of interactions (e.g. digital outputs provided by pupils on teachers' requirement) shed light on the identified expertises and tasks which have been distributed within groups. We must point out that the interweaving of different codes (e.g. image, text, sound) was an assessment criteria constantly repeated. We are then not able to assume that the pupils' outputs would have been spontaneously multimedia without this academic demand. In any case, digital outputs highlighted once again skills heterogeneity among pupils and the significant importance of extra-curricular time in the collective organizations. Such an observation leads to question the role of these outputs in the amplification of inequalities among pupils. Indeed, outputs were most often carried out on free time. Then personal devices owned at home as well as technical and informational skills that teenagers already gained, become a major factor of success and distinction. Teachers however must be able to support and train pupils in the classroom or school place in order to formalize and structure knowledge, especially regarding specific requirements such as the diversity of media types employed providing outputs. Observations demonstrated that skills were largely transformed within the group. Group work allowed for the emergence of a relative complementarity between individuals, either in terms of the distribution of tasks according to the skills and capacities assumed by each member, including leadership effects, or in terms of transfers of expertise from one individual to another or to the whole group. This did not necessarily encourage individual learning, as students may remain confined within or outside their areas of expertise. The distribution of skills and knowledge within the groups was based on three points: collection of information, writing and synthesis, communication. Several and multimedia combinations affected reading and writing tasks: on-screen reading and writing (taking notes) on paper, reading and writing on computer or on paper, reading on paper and writing on computer or even on a phone. In these strategic and cognitive configurations, tools and spaces, personal as well as academic, play indeed an important role.

The conditions of a possible distributed literacy

Forms of "distributed cognition" exist when interaction between cognitive technologies linked to a particular environment (a workspace for example) and exchange spaces linked to social arrangements (in a type of task required) create collaborative learning modes [START_REF] Conein | Cognition distribuée, groupe social et technologie cognitive[END_REF]. Spaces, media types, devices, finding and processing information methods, can be considered as informational tools. High school students can use a very wide range of tools that are likely to allow them to vary the methods of information access and processing. The choice of tools, and especially ways one uses them, depends initially on what the social environment, firstly at home, offers to each student, even if the statistics show in France a global high rate of digital equipment.

School have then to democratize tools and ways to use tools, that students do not usually use, or even know, on a daily basis, especially in three main areas: information seeking (catalogs), information storage and management (indexation), processing and communication (publishing tools). As pupils tend to work a lot outside of school time, special attention must be paid to spaces and settings. They may use public spaces (libraries or school libraries) to continue their work, while they may also have to be satisfied with what they find at home, "information fluent" or not.

Conclusions

Our findings highlight that the notion of Transliteracy is built on five key points: the relation to the group (social factor), the relation to semio-technical contexts (spaces, media, devices, procedures for finding and processing information), the relation to legitimacy (cultural factor), the relation to time (temporal factor) and knowledge format (cognitive factor). These elements require particular attention in the context of information literacy strategies.

Activities observed show that the broadest divide is between school culture and individual information practices. On the teachers' side, students' technical abilities are often overestimated. The consequence is a discrepancy between expected and real digital skills [START_REF] Dioni | Métier d'élève, métier d'enseignant à l'ère numérique : Rapport de recherche pour l'INRP[END_REF]. This persistent overestimation tends however to neglect actual learning needs, even basically technical ones. This is a key point, useful for the information literacy field of research as well as for educators. For instance students see their teachers as not technically experts but as information validating experts in relation to educational requirements. They are therefore often requested to help in this validation stage, whereas there is a paradoxical injunction of independence since pupils are summoned to be experts and critics without necessarily having all the cognitive tools to do so. These shifts can slow down group dynamics or creativity. Moreover, whether French high-shool pupils still need to improve their proficiency in validation of information and critical thinking, teachers' recommendations are likely to replace pupils' personal reflection. Our findings, and the theoretical angle we choose to implement, highlight the gap between actual cognitive processes and the representation of legitimate knowledge. More precisely, a bridge is to be built between the informational universe of the Web, moving and fuzzy, and the school universe that structures communication, formats and legitimacy.

The ability to manage free time and to work outside schooltime is very unequal [START_REF] Le Douarin | Une sociologie des usages des TIC à l'épreuve du temps libre : le cas des lycéens durant l'année du baccalauréat[END_REF].

Working outside classroom or schooltime, remotely, requires a pupil's know-how, in the sense of Coulon [START_REF] Coulon | Un instrument d'affiliation intellectuelle[END_REF]. It does not only depend on technical skills or mastery of tools, but on a consistent level of self-esteem to take ownership of working methods: e.g. connecting to the school's VLE, consulting documents and taking enough time to learn, in a process of affiliation to the group or class and its activities. As collaborative learning and group work are a major requirement of current education programs, our results point out how much sharing tasks could be time consuming for students leading to reduced cognitive effectiveness. This dilution can be offset by social exchanges between peers, and the emergence of expertise distributed in working groups around certain media such as the blog.

The daily digital tools make it possible to rely on familiar communication formats, common to daily uses as well as academic ones: lists, collections, index, for instance featured on social networking sites or blogs. It is an opportunity for students to create their own spaces-time of socialization and learning, different from the strict time and space frame imposed by school. Our transliteracy based-approach point out that it has to be managed by teachers however. Teenagers are used to listening to music and working at the same time, managing personal and academic purposes at the same moment even with the same tools. The knowledge format remains a benchmark that makes it possible to distinguish what belongs to the content of the knowledge included in a specific and imposed form and that what belongs to the context of learning. The proposal of varied knowledge formats allows the setting up of communication conditions and provides a framework facilitating the emergence of transliteracy skills. The logbook for example, is rather usual in the French educational system and required in activities, but is actually often reduced to a formal and unefficient pedagogical tool. The logbook can however become a real cognitive and didactic tool for training, for storing, sharing and documentarizing collected information. Finally, a specific communication format (for example video) makes it possible for pupils to think about alternative outputs or ways of communication and to reduce the contradictions they perceive between familiar multimedia arrangements and constrained school formats (for example dissertation). The design of information through production of content can also be seen as a mode of grammatization of uses based not only on the procedures but also the critical reflection, not only on problem solving but also on the discovery of questions.

Regarding the keys factors mentioned above, Transliteracy is likely to be facilitated by group work and the multiplication of tools, but rather obstructed by cultural constraints: representations of what is legitimate or not, expressed in traditional knowledge formats. On this matter of cultural construction, representations and construction of meaning, the role of the teacher becomes essential for the emergence of forms of Transliteracy.