Aous Karoui
email: aous.karoui@univ-lemans.friza.marfisi@univ-lemans.fr

Iza Marfisi-Schottman

Sébastien George
email: sebastien.george@univ-lemans.fr

Towards an Efficient Mobile Learning Games Design Model

Keywords: game-based learning, mobility, location-based learning, teacher, pedagogic objective

Classrooms are increasingly equipped with information and communication technology and especially interactive mobile devices. However, the latest studies show that their use by teachers is still very limited because of a lack of resources and applications adapted to an educational use. Indeed, there seems to be a shortage of mobile learning practitioners due to the time required for these tools' apprehension. Likewise, studies show real needs to expand the variety of applications, resources and activities available on these mobile devices, in order to make them more suited to the teachers' pedagogic objectives. Concurrently, new ways of using mobile devices for education are arising. Among those directions of use, research conducted on Mobile Learning Games (MLGs) seems particularly promising. In this paper, we propose to identify several MLGs, from the most referenced scientific assessments, that have been carried out in educational context, in order to determine their common features and impact on learners, and to identify challenges in terms of design, storyboarding and student monitoring. Thus, we can discuss how far research on MLGs has gone in terms of pedagogical effectiveness and whether there are still challenges that teachers will be facing regarding the design and execution of MLGs. At this level, we try to define the main characteristics of the analysed MLGs, and identify the recurring problems that occur when teachers use them. First, this will allow us to establish several guidelines for designing MLGs. Secondly, in order to diminish the constraints of use, we discuss new ways of implementing MLGs. Furthermore, we propose a global MLGs model, capable of capitalizing the identified main characteristics and overcoming the recurring problems at the same time. Finally, we discuss the possibility of implementing this model through an authoring environment.

Introduction

Today, mobile devices such as smartphones and tablets are widespread among teenagers. Indeed, in 2013, 53% of Europeans between 9 and 16 years old possess a smartphone, and 28% of them daily use tablets ( [START_REF] Mascheroni | Mobile internet access and use among European children: initial findings of the Net Children Go Mobile project[END_REF]. This increasing use of mobile devices has recently been followed by the awareness of their potential for learning inside and outside the classroom [START_REF] Johnson | The NMC Horizon Report: 2013 Higher Education Edition[END_REF]. Hence, many European countries have established digital integration programs in their schools over the last years, such as the MoLeNET project in the UK, that can be considered as the world's largest implementation of mobile learning, involving 20,000 learners in 115 colleges and 29 schools [START_REF] Attewell | The impactof mobile learning examining what it means for teaching and learning[END_REF]. In France, national directives are also encouraging educational institutions to experiment tablets in classrooms. The "Académie de Nantes" project for example integrates tablets into schools and reports their affordances for learning and provides detailed findings on their use by pupils 1 . Furthermore, in the USA, 43% of teachers and/or their students use e-readers and tablets in classrooms [START_REF] Purcell | How teachers are using technology at home and in their classrooms[END_REF]. However, among all these ongoing programs, the New Media Consortium (NMC) Horizon Report [START_REF] Johnson | Horizon Report Europe: 2014 Schools Edition[END_REF] shows that there are needs to expand the resources and activities available on these mobile devices in order to make them more suited to teachers' pedagogic objectives. On the other hand, the concept of learning games is gaining support among educators who recognise that games can increase engagement, creativity, and authentic learning [START_REF] Papastergiou | Digital Game-Based Learning in high school Computer Science education: Impact on educational effectiveness and student motivation[END_REF] [START_REF] Johnson | Horizon Report Europe: 2014 Schools Edition[END_REF] [START_REF] Aceto | Mapping and analysing prospective technologies for learning results from a consultation with European stakeholders and roadmaps for policy action[END_REF]. In addition, now that tablets and smartphones are commonplace, game play is becoming a mobile activity. Hence, mobile games new abilities such as location-based activities [START_REF] Schlieder | Geogames: Designing location-based games from classic board games[END_REF] and collaboration [START_REF] Sánchez | Problem solving and collaboration using mobile serious games[END_REF]) motivated recent work on integrating learning games on mobile devices. In fact, we believe that mobile gaming will fit very well with the behaviour of teens, who are already used to playing games on their smartphones and other hand-held devices such as Nintendo DS 2 and PSP 3 .

Although mobile game-based learning is still in its nascent stages, we propose in this paper, to look more closely at certain existing examples of Mobile Learning Games (MLGs). Through a critical lens, we discuss how far research on MLGs has gone in terms of pedagogical effectiveness and whether there are still challenges that teachers will be facing regarding the design and execution of MLGs.

To answer these questions, we propose to identify five MLGs, from the most referenced scientific assessments, that have been carried out in educational context. We analyse these MLGs in order to highlight their common features and identify the recurring problems of use. This will allow us to establish several guidelines for designing MLGs. Then, we discuss the possibility of creating a MLG design model that integrates those common features and overcomes the identified problems.

Bibliographic research of Mobile Learning Games

In this section, we first present our method to identify MLGs having notable success in the research field. Then we describe the procedure for selecting the ones we analyse in this paper.

Identifying successful Mobile Learning Games

In order to outline our screening set, we decided to focus only on MLGs, which have already been assessed in an educational context. We used the following keywords to search for scientific articles: "evaluation" + "mobile" + "learning game". Then, in order to cover all terminologies used in the field, we replaced the term "mobile" by the following terms: "location-based", "pervasive" and "contextual". Our research method consists in selecting the MLGs that appear among the first results obtained with the above keywords, on four major scientific search engines: IEEEXplore, ACM Digital Library, Science Direct and Springer. In addition, to reach a wider scope, we decided to expand our literature search on the meta-search engine Google Scholar. At this point, we chose to retain only the articles evaluating MLGs with executable prototype and described according to the evaluation heuristics defined by [START_REF] Zaibon | Heuristics Evaluation Strategy for Mobile Game-Based Learning[END_REF] in terms of game usability, mobility, gameplay and educational content. Due to the large number of results, we retained only the first ten MLGs appearing on each engine, in accordance with our search criteria and sorted by relevance. Although the algorithm that determines the degree of relevance varies from a search engine to another, it always takes into account the presence of keywords in the full text of the article, the name of the author and the publication in which the article appeared. Table 1 contains the 50 MLGs obtained with this research method (5 engines x 10 results). There are actually 39 distinct MLGs because some of them figured on several engines (in bold in Table 2). Note that we only mentioned each MLG once per engine, even if it was cited by several articles.

Selection method

In order to identify the MLGs to be analyzed, we decided to sort them by total number of citations (sum of citations of all articles evaluating the same MLG).

Citations

Total Citations Frequency1550 [START_REF] Huizenga | Mobile game-based learning in secondary education: engagement, motivation and learning in a mobile city game[END_REF] 146 313 [START_REF] Akkerman | Storification in History education: A mobile game in and about medieval Amsterdam[END_REF] 75 [START_REF] Admiraal | The concept of flow in collaborative gamebased learning[END_REF] 69 [START_REF] Admiraal | Technology enhanced learning through mobile technology in secondary education. Expanding the knowledge economy[END_REF] 12 [START_REF] Huizenga | Learning history by playing a mobile city game[END_REF] 11

The MobileGame [START_REF] Schwabe | Mobile learning with a mobile game: design and motivational effects[END_REF] 212 240 [START_REF] Schwabe | Mobile learning with a mobile game: design and motivational effects[END_REF] 28

Explore! [START_REF] Costabile | Explore! Possibilities and Challenges of Mobile Learning[END_REF] 104 179 (Ardito et al., 2008) 35 [START_REF] Ardito | Enabling Interactive Exploration of Cultural Heritage: An Experience of Designing Systems for Mobile Devices[END_REF] 18 (Ardito & Lanzilotti, 2008) 11 [START_REF] Ardito | Enriching Archaeological Parks with Contextual Sounds and Mobile Technology[END_REF] 10

Power Agent [START_REF] Gustafsson | Evaluation of a Pervasive Game for Domestic Energy Engagement Among Teenagers[END_REF] 49 88 [START_REF] Bang | Promoting New Patterns in Household Energy Consumption with Pervasive Learning Games[END_REF] 39 Skattjakt (D. Spikol & Milrad, 2008) 39

79

(Daniel Spikol & Milrad, 2008) 34 [START_REF] Spikol | Designing Mobile Games that Explore Novel Learning Practices with Co-Design[END_REF] 3 [START_REF] Spikol | Exploring Novel Learning Practices Through Co-Designing Mobile Games[END_REF] 3

Description and analysis of MLGs

Now that we have identified the five most referenced MLGs, we will describe their educational purpose and scenario. We also provide the context and the results of their latest and most complete assessment.

Frequency1550

Educational purpose

Frequency1550 is a MLG about medieval Amsterdam to be played during a single school day.

Scenario description

In this game, pupils are assigned the identities of foreign workers in medieval Amsterdam who would like to obtain citizenship. Each group of 4 to 5 pupils is divided into a City Team (CT), who will walk through the city, and a Head Quarter Team (HQT), operating from behind a computer in the Waag building5 . After the lunch break, the teams switch places so that every pupil tries the role of both teams. The CT can only view a map of medieval Amsterdam on their smartphones, while the HQT can use two maps, one with medieval Amsterdam and another one with present Amsterdam, and can digitally follow the route of the CT by means of GPS, so they can guide them towards the required learning tasks using internet resources and media information received from the CT. At the end of the day, pupils gather at the Waag building for a debriefing session where each group presents their collected media to the other groups and to the teaching staff.

Assessment context

The game was tested on 458 pupils aged form 12 to 16: 232 played the Frequency1550 game and 226 followed formal lessons on the same learning content [START_REF] Admiraal | The concept of flow in collaborative gamebased learning[END_REF].

Assessment results

Frequency1550 players scored higher at knowledge test than those who received formal lessons. According to the authors, the players were able to gain more knowledge through their direct presence on historical sites. It even seems that when students failed at parts of the game, location-based experience enabled them to learn anyway.

In addition, the fact that the scenario was designed in such a way that teams needed to communicate in order to accomplish game tasks (CT sent historical information and pictures found on sites to HQT so that they could find out more about them on the internet), led to a successful collaboration between the teams. The HQT members were more motivated than the CT members because they felt a sense of control when guiding the CT and because of the diversity of their tasks (internet research, orientation and giving orders).

On the other hand, the authors noticed that some players were distracted by external events such as accidents in the street, and sometimes lost sight of the overall structure of the game. The CT members generally experienced a lack of control and vision of the game. According to some players' interviews, it is also possible that playing the game for a single day is not enough to reach the maximum level of immersion.

The MobilGame

Educational purpose

The MobileGame is a MLG designed to help new students get familiar with the building and the services on their university campus

Scenario description

The game consist in guiding participants along a map and through several missions to discover places in the university such as the library, the cafeteria or laboratories. Contextual tasks are included in the assignments such as finding a book in the library or a person in a department. Players can play individually or in groups of two, three or four people. Tasks are accomplished through mobile devices and are divided into cooperative and competitive missions. The competitive mission are based on hunting rules: each group tries to catch another group and, is itself hunted by a third group. The handheld device shows the location of the hunter and the prey. The cooperative missions force groups to meet with each other and with teachers in order to exchange information. Again, they are supported with location-based information on their mobile screens.

Assessment context

The evaluation was conducted with 22 students from 19 to 25 years at the University of Koblenz in Germany [START_REF] Schwabe | Mobile learning with a mobile game: design and motivational effects[END_REF].

Assessment results

The majority of players (17 of 22), said they would like to play the game again, and 21 thought the electronic support increased the excitement of the game.

Regarding the gameplay, half the participants saw a considerable added value in comparison with a traditional guided tour. Moreover, 8 participants selected "the opportunity to individually explore the university" as one of the three most important positive aspects of the game.

According to the survey, map-navigation activities (moving through the digital map) and 'Hiding and hunting' activities (chasing prey groups and avoiding hunters) obtained the highest score in terms of immersion and distraction.

Gaius' Day in Egnathia

Educational purpose

Gaius' Day in Egnathia is a MLG designed to learn about the archaeological park of Egnathia in southern Italy.

Scenario description

Players are divided into groups of 3 or 5. Each group impersonates a Roman citizen (Gaius), who settle down in Egnathia with his family. Group members play different roles: the reader; who reads the challenge, the petitioner; who consults the glossary, the navigator; who carries the map and marks the identified places, the scouts who go on ahead to find the places that are the targets of the mission.

The game exists in two versions. The first one is a paper-based version. Therewith, players are equipped with booklets containing the map and the challenges. The second version is implemented by the Explore! the mobile learning system. This time, the game information and assignments are displayed on cellphones. Sound effects indicating the beginning and the end of assignments and 3D representations of what places looked like at the time are included in the Explore! version.

In both versions, the game is supervised by a game master, whose main tasks are to check that the rules are observed correctly, encourage the players if they run into difficulties, and push them in the right direction by giving them suitable hints. Finally, a debriefing session take place in order to discuss the acquired information.

The whole game lasts about three hours.

Assessment context

The article we report describes two studies of playing Gaius'Day in Egnathia on mobile phones (Explore! aiming to compare behavior, engagement and learning with the original paper-based version. The first study involved a class of 24 students, from 11 to 13 years old, playing the paper-based game. The second study involved a total of 42 twelve years old students; 19 of them played the paper-based version and 23 played the Explore! version.

Assessment results

The results indicated a positive reaction to Explore! version. 74% of the students explicitly reported having preferred Explore!, only 13% preferred the original game and 13% did not express any preference. The 3D reconstructions on mobile screens during the gameplay and the debriefing, were the primary reason for preferring Explore! However, results showed more right answers in the game assignments for the paper version. The authors explain this difference by the fact that the Explore! version showed only relevant information corresponding to the exact GPS position of students while in the paper version, students always had access to all the data. Additionally, the Explore! version required students to respond to the questions in a certain order while in the paper version, they could choose the order of their answers and even return to some of them later in the game. Motivation was very high in both versions of the game but even more so for the Explore! version. The motivation factors were related to the used artifacts (such as the sound and augmented reality effects) for the Explore! version, while for the paper version, they were related to the archaeological park.

Power Agent

Educational purpose

Power Agent is a MLG designed to educate players about energies and teach them good consumption habits.

Scenario description.

Players take the role of a special agent whose mission is to save energy at home. To achieve this goal, the agents act under the supervision of their director "Mr. Q". Each agent is equipped with a mobile phone connected directly to the electric power meter in their home and must cooperate with the members of his family to reduce consumption between 5PM and 10PM. Then, his efforts are combined with other agents in the same city. The team of special agents is in competition with another team in another city. The winning team is the one that decreases its energy consumption the most over a defined time period.

Assessment context

Two teams of three agents, along with their family members, participated in the game for 10 days in two different cities in Sweden during the spring of 2008. Coincidentally, the first team consisted of three boys and the second team consisted of three girls.

Assessment results

Players were highly motivated and committed to the game and accepted a lower daily comfort level than the standard. According to the authors, the configuration of the two teams (girls' team and boys' team) improved the competitive aspect of the game. Thus, they recorded several outstanding initiatives among agents such as replacing light bulbs with energy saving ones or using candles. Collaboration aspect within families was considerable and an important immersive factor. Indeed, parents were quite involved in the game and even communicated with "Mr.Q" through their children. The educational objective was also achieved in most cases: players learned new methods to reduce consumption through the strategies exchanged on the game's web platform, by applying these strategies and discussing with their family and team members. The MLG led to considerable changes in behavior during the 10 days period of the game but the assessment did not allow to measure the long-term effects.

Skattjakt (treasure hunt)

Educational purpose

Skattjakt is a MLG designed to promote physical activity and collaborative problem-solving while learning about history.

Scenario description

The game takes place in a castle. The main assignment is to help the ghost of Anna Koskull (former lady of the manor), to solve the mystery of her missing husband, who actually built the castle. While exploring the map displayed on their smartphones, players receive text and audio based clues to find landmarks. Therewith, they have to solve puzzles, spell out codes and collaboratively unscramble clues directing them to other landmarks. Moreover, they lose time each time they give wrong answers.

Assessment context

The study that we report, was firstly carried out on 12 pupils between 12 and 15 years old during the winter in 2007, and secondly, on 26 girls aged between 13 and 15 years old, during the summer of the same year.

Assessment results

For the first experiment, 58% of players said the game was very entertaining and 73% for the second one. This could be partly related to the weather conditions in which the game took place (Swedish winter vs summer). The gameplay also increased motivation to learn. Indeed, 100% of the players appreciated learning local history through the game in the second experiment and 75% gave the same feedback after the first experiment. Furthermore, even collaboration improved during the second experiment. The results indicate that 92% of the players in the second experiment (who were only girls) were able to collaborate all the time against only 58% in the first experiment.

Discussion

All the analyzed MLGs obtained good results in terms of learning effectiveness and high results in terms of gameplay satisfaction. So, we will firstly identify the common features which contributed to these games' success. Secondly, we will discuss the problems faced by players during the games assessments in order to analyze them from a design point of view (teacher's position).

Common features

Location-based learning

Location-based activity is a common feature to all the analyzed MLGs. It is obviously a pedagogic choice to use location-based activities as a learning mechanism. When games use this feature, they are called Geogames, according to [START_REF] Schlieder | Geogames: Designing location-based games from classic board games[END_REF]. At this level, we can say that our analysis set consist of five Learning Geogames. Given some of the assessments results, we conclude that the location-based experience is an effective way for learners to acquire information because of their direct presence on the learning spots, the possibility of observing and therefor better memorizing places, names and functions. Indeed, Frequency1550 players have scored higher in the knowledge test, than those who had received formal lessons. Furthermore, pedagogical information in this game was sometimes acquired indirectly: players didn't always succeeded the game's assignments but always learned something from the context around. Location-based learning also helped both teams that played Power Agent to learn about the required consumption habits in a practical way. Truly, we believe that it is more efficient to directly practice the learned methods in a realistic situation rather than just receive them in a theoretical form.

Learning autonomy

One of the most important elements characterizing Geogames is the moving ability. This feature fits ideally with the autonomous learning method. Actually, many studies recommend autonomy in learning because it is closely linked to motivation. Indeed, personal involvement in decision making leads to more effective learning [START_REF] Dickinson | Autonomy and motivation a literature review[END_REF] [START_REF] Knowles | Self-directed learning: a guide for learners and teachers[END_REF]. Autonomy is also valued by the players. Indeed, the majority of The MobileGame participants selected the possibility to individually explore the university as one of the most positive points of the game. In addition, the players of Gaius'Day who could freely answer the questions, scored higher than those who were constrained to answer in the implied order. Moreover, CT members in Frequency1550, who had less autonomy than the HQT, expressed less satisfaction for the gameplay. Hence, we recommend more autonomy of movement and decision when designing MLGs scenarios. Indeed, we believe that enabling students to find items, explore sites, and choose strategies increases personal involvement and hence, leads to more effective learning.

Role-playing pedagogy

Role-playing was common to four of the five analyzed games. Indeed, in Frequency1550, players had to play the role of foreign workers in medieval Amsterdam, roman citizen in Gaius' Day, special agents in Power Agent and investigators of a fictional research group at the university in Skattjakt. Role-play has been often used in education as a learning mechanism. [START_REF] Heuser | Service-Learning as a Pedagogy to Promote the Content, Cross-Cultural, and Language-Learning of ESL Students[END_REF] for example used roleplay to cultivate college students' understanding of poverty and homelessness in the United States. It has also been used with high school students in South Africa as part of a repertoire of activities for "multimodal exploration of texts" [START_REF] Stein | Reconfiguring the Past and the Present: Performing Literacy Histories in a Johannesburg Classroom[END_REF]. In addition, since it requires students to embody characters and perspectives that may be quite different from their own, role-playing activities can be cognitively challenging [START_REF] Shapiro | A critical role for role-playing pedagogy[END_REF]. Thus, we believe it can be a valuable addition to the gameplay experience and we recommend to integrate it in MLGs scenarios if there are suitable conditions.

Collaborative learning

Setting up collaborative activities between players is recognized as one of the mechanisms that enhances games. This is due to the social interactions and the extra challenge of team decision making [START_REF] Marfisi-Schottman | Supporting Teachers to Design and Use Mobile Collaborative Learning Games[END_REF]. Indeed, cognition is better when it becomes a result of a distributed process across members of a group [START_REF] Hollan | Distributed Cognition: Toward a New Foundation for Humancomputer Interaction Research[END_REF]. All the analyzed MLGs in this paper include collaborative learning methods since all the studied scenarios were based on group problem-solving. Hence, social interactions were promoted. For example, the involvement of the whole family in Power Agent improved the immersion of agents and made the game more challenging for them. Moreover, the authors reported that the randomly composition of teams by a girls' and a boys' team improved competitiveness. In addition, collaboration has been more successful among the girls teams compared to the mixed team in Skattjakt. This leaves us to say that, in some cases, it is possible to draw profit of the competitiveness aspects between the sexes to promote engagement. Social and epistemic factors, such as age and relationship between players, can advantageously be taken into account to facilitate the design of such competitive activities [START_REF] Hamalainen | Designing and evaluating collaboration in a virtual game environment for vocational learning[END_REF].

Innovative digital tools

Innovative digital tools makes the learning process more attractive. Indeed, according to the games observations, motivation was always higher when it integrated new digital tools. The experimentation of Frequency1550, for example, showed that players were more attentive and reactive when teachers explain how to use the mobile devices than during the explanation of the game's history. The augmented reality (AR) features also seemed to motivate Gaius' Day players and the 3D representations provided by Explore! allowed richer after-game discussions and a longer debriefing phase than the paper version. We therefore preconize combining AR techniques like QR/Flash codes and sound effects as well as including multimedia content to enhance MLGs attractiveness.

The problems of use

In this part, we will analyze the problems encountered by players during the gameplay and interpret them through the teacher's lens in order to determine possible solutions.

In terms of gameplay

Some players of Frequency1550 lose sight during the assignments time and were distracted by external events. To overcome this kind of circumstances and to avoid distractions in general, a game master should always be planned in MLGs scenarios. The teacher can advantageously incarnate this role. Indeed, we believe that the monitoring progress is particularly well suited for the teachers so they can help players in difficulty. Therefore, providing MLGs with tracking tools so that teachers can supervise the players' progress in the game could be very useful. Providing alternative paths in the game scenario and additional activities would also be an efficient solution to manage the different levels of player's.

In terms of design

Skattjakt players regretted that it was impossible to play the same game on other topics than history. Similarly, the authors of Gaius' Day (tested on Explore!) expressed their needs to make their authoring tool more generic to other topics besides archeological parks. Currently, there are several authoring tools allowing to design and execute Learning Games such as eadventure6 and Storytec7 . However, these authoring tools do not provide the means to design located-based activities or using innovative digital tools which are essential to MLGs. Consequently, we believe that a generic model and tool for designing and executing Learning Games on mobile devices would be very advantageous. Therefore, our future work will be focused on establishing such a generic model. We will concentrate on integrating the previously identified MLGs features in our system's database in order to guide designers to create MLGs in the most efficient way. Nevertheless, possibilities of reification of this model are multiple since we can take advantage of the existing authoring tools cited above. Thereafter, (Figure 1) illustrates the process that we will set up for our authoring environment in order to assist the designers to create their custom MLG. The process takes place primarily between the designer and the authoring tool system. The idea of the operating method is that designer inserts information about context and content of his MLG and that the system gradually propose components (e.g. scenario patterns) and support (e.g. findings of this review) based on the provided information.

Towards an Efficient Mobile Learning Games Design Model

Conclusion

In this paper, we sought to identify the principal common features that contributed to five MLGs success. On the one hand, we found that location-based autonomous learning, role-playing pedagogy and collaborative learning were the main features of the analyzed five MLGs. On the other hand, we exposed particular design and gameplay problems to which we have proposed possible solutions; such as the risk of distraction especially when playing outside and the question of managing different players' progress in the MLG.

Although we have identified interesting MLGs, our research method leaves out recent MLGs whose articles have not yet been much cited, but who potentially implement several mechanisms found in the last part of this article. For example, Power Explorer is a MLG that enhances the learning process found in Power Agent in order to achieve long-term changes in consumer habits.

The next step of our work is to define a generic authoring environment for non-computer scientist such as teachers, museum curators and park managers, so that they can design their own games and deploy them on mobile devices.

Figure 1 :

 1 Figure 1: The MLG authoring environment process

Table 1 : The first 10 MLGs found for each search engine

 1

	IEEExplore	ACM DL	Science Direct	Springer	Google Scholar
	Skillville	On the Edge	Bauboss	HeartRun	The MobileGame
	Lecture Quiz	Chinese-PP game	HeartRun	ToneWars	Explore!
	Skattjakt	Parrot Game	QuesTInSitu	Power Agent	Frequency1550
	Bagamoyo Caravan	Frogger&Floored	Frequentie1550	MobileMath	Skattjakt
	FreshUp	Power Agent	EarlyBird	Explore!	Parrot Game
	Cardinal direction	Kurio	Furio's	Detective Alavi	Frogger&Floored
	Tower of London	Power Explorer	MSGs	Preserving Famosa	Power agent
				fortress
	The Amazing City	iFitQuest	Reenactment	Mindergie	Lecture Quiz
	CatchBob!	Explore!	BoomRoom	Language Learning	MuseumScrabble
				Game
	The MobileGame	TimeWarp	EasyLexia	Nat. Palace Museum	Mentira
				Adventure

Table 2 :

 2 Table 2 lists the MLGs shortlisted in Section 2.1, sorted by total citations on Google Scholar. 4 Order by total number of citations of preselected MLGs.

	MLG	Reference /
		publishing year

The complete list of MLGs sorted by total citation is available on: http://perso.univ-lemans.fr/~akaroui/table_mlgs.html

http://en.wikipedia.org/wiki/Waag,_Amsterdam

http://e-adventure.e-ucm.es/

http://www.storytec.de/index.php?id=2&L=1


Iza Marfisi-Schottman

Pierre-Yves Gicquel
email: pierre-yves.gicquel@univ-lemans.fr

Sébastien George
email: sebastien.george@univ-lemans.fr

Meta Serious Game: Supporting Creativity Sessions for Mobile Serious Games

Keywords: Serious Game, design, Mobile Serious Game, Collaboration, Board Game

The early stages of Mobile Serious Game (MSG) design are very complex. That is why many MSG research projects start with a brainstorming session, involving pedagogical and game experts. However, brainstorming with large groups of participants, who come from very different backgrounds, can prove to be long and inefficient. In addition, classic brainstorming techniques are not well adapted to the large number of constraints and technical limitations that need to be taken into account when designing MSGs (e.g. educational content, number of students, duration of field trip, fences). Our hypothesis is that the first stages of design can be efficiently supported by a board game. Indeed, games have proven to be very efficient to support collaboration and enhance motivation and they can be designed in such a way to encapsulate constraints in their game rules. In order to test this hypothesis, we created a meta-SG: a game for designing a botanical MSG for a natural park. The experimentation we conducted with 17 designers was very encouraging. The analysis of the videos, questionnaires and produced scenarios showed that the meta-SG generated a very lively and productive creativity session, and the constraints related to MSG design were not perceived as limitations but as challenging game rules.

Methods for First Stages of Mobile Serious Game Design 1.1 Designing Mobile Serious Games

Designing Serious Games (SGs) for education is a complex process that involves several actors: SG experts, who have experience in using game mechanics to enhance learning, and educational experts, who master the didactics of the target pedagogical skills. The design of Mobile Serious Games (MSGs) requires a third type of actor, who masters the MSG's use context. This context is not limited to a set of measurable physical settings [START_REF] Dourish | What we talk about when we talk about context[END_REF]; it also contains domain specific notions that can only be identified by field experts who have a deep understanding of the physical context (e.g. location, boundaries, physical limitations) in which the MSG will take place. MSGs for museums, for example, need to be designed with a museum curator, in order to fit specific rooms and exhibits [START_REF] Lonsdale | Context awareness for MOBIlearn: creating an engaging learning experience in an art museum[END_REF]. Another important aspect to take into account when designing MSGs is the time context. For example, if a MSG is designed for a field trip, it must not last more than the time planned for this outing. We therefore adopt a design-based research method [START_REF] Whang | Design-based research and technology-enhanced learning environments[END_REF], implying deep collaboration between our team of SG experts, pedagogical experts and field experts. Unfortunately, these experts have little time to offer for work sessions. As many before us, we were confronted to this problem during the ReVeRIES1 research project. The goal of this project is to use mobile technologies to help humans recognize the trees that surround them, in a fun and motivating way. It involves SG experts, computer scientists, several botanists and botanical park managers. The main objective of our first creativity session was to help these experts collaborate, in order to produce plausible MSG scenarios, for the Echologia Park2 . These scenarios will be used as a basis to build an authoring tool for the park owners to create their own MSGs. We therefore needed to help the designers in producing a large number and variety of MSG scenarios, adapted to Echologia's constraints, and in particular to the park's morphology (e.g. fences, trees) and the park's visitor profiles (e.g. groups of teenagers, families). In the next section, we investigate the strengths and weakness of existing tools and methods for organizing such creativity sessions.

Investigating Tools and Methods Used for Creativity

The Original Brainstorming Method

The first idea that comes to mind to boosts creativity is to use brainstorming. Here are the four guidelines of the original brainstorming method [START_REF] Osborn | Applied Imagination: The Principals and Procedures of Creative Thinking[END_REF]:

"1. Criticism is ruled out. Adverse judgment of ideas must be withheld until later. The purpose of the brainstorming session is the generation of many, varied and unusual options. 2. Freewheeling is welcomed. The wilder the idea, the better. […] 3. Quantity is wanted. The greater the number of ideas, the greater the likelihood of useful ideas. 4. Combination and improvement are sought. In addition to contributing ideas of their own, participants should suggest how the ideas of others can be turned into better ideas[…]" These guidelines do not adapt well to the design of MSG scenarios. First of all, the guideline 2 seems very difficult to follow. "Wild and unusual ideas", even if they are inspiring, have no use if they are not feasible. There is no interest in designing scenarios that are impossible due to the physical layout of the park, that have ill-adapted educational content or that are technically impossible to develop. Since computer scientists, botanists and natural park owners usually have a very sparse representation of each other's fields, they have to rely on each other to validate their ideas. This is where guideline 1 seems problematic: "criticism is ruled out". Of course, we have to avoid personal criticism, but it is essential for the designers to be free to indicate if a proposal raises incoherencies related to their field of expertise. The third guideline is interesting; a creativity session should produce a large set of new ideas. However, in the context of the ReVeRIES project, there is a trade-off to be made between the quantity of imagined activities and the level of detail with which these activities are described. At the end of the creativity session, we need the activities to be precise enough to propose an executable MSG model. In practice, very few "brainstorming sessions" strictly obey these rules. Designers usually integrate additional methodologies and tools to structure these sessions and guide designers. In particular, we investigate two tools used for SG design: inspiration cards and personas.

Inspiration Cards

An inspiration card [START_REF] Halskov | Inspiration card workshops[END_REF]) is a physical piece of paper on which either a domain specific knowledge or a technological possibility is described. For instance, in the case of botanical SGs, a technological card could describe "augmented reality" and a domain specific card might describe "the organization of fauna in families, genres and species". In practice, these cards can be used as creativity bootstrap for various phases of creativity. For example, they can be used to help SG designers construct a shared understanding of the cards content. Designers can also freely associate cards to imagine original SG scenarios. The principle of inspiration cards has been used in numerous design activities such as designing tangible learning games [START_REF] Deng | Tango cards: a card-based design tool for informing the design of tangible learning games[END_REF] or to help designers to integrate game elements in an existing product [START_REF] Lucero | PLEX Cards: a source of inspiration when designing for playfulness[END_REF]. It is worth noticing that there is no standard for the way inspiration cards should be used, neither for their content. The concept of inspiration cards seems interesting for MSG design as they help designers in focusing on what is actually feasible while still granting them a lot of freedom in the design process. Moreover, cards are a good medium for engaging collaborative discussions between experts, allowing them to gain a shared understanding of their meaning.

Personas

Personas represent archetypes users of the future system [START_REF] Pruitt | Personas: practice and theory[END_REF]. They are very useful to help designers keep in mind the motivations and needs of future users. Personas can be represented by cards describing a plausible user profile (e.g. name, gender, age, profession, expectations regarding the system...). Giving precise information such as name and age makes the persona more realistic thus helping designers to project themselves into the persona. Personas are often used in Human Computer Interaction (HCI) design.

Inspiration cards and personas seem to be efficient tools to help designers come up with technically feasible and sound scenarios adapted to the park's visitor profiles. However they do not facilitate the design of MSGs that are adapted to the physical and time context of the park. In addition, they are not particularly enjoyable to use and fun essential for boosting creativity sessions [START_REF] Fullerton | Game Design Workshop : A Playcentric Approach to Creating Innovative Games[END_REF]. Which leads us to the hypothesis that a game could be appropriate for mediating the collaborative design of MSGs. In this paper, we therefore test this hypothesis by creating a meta-SG: a game to support creativity sessions for botanical MSGs at the Echologia Park. In the next section, we explain how we transform the design constraints related to this park into game mechanics for the meta-SG. In the third section, we describe how this meta-game was used for a design session involving 17 participants. We then conclude with several perspectives.

Transforming Design Constraints into Game Mechanics

As explained in the previous section, MSG design is subject to many constraints: pedagogical, technological and physical. All these characteristics are difficult to take into account without limiting the designer's creativity. We therefore propose to transform these constraints into game mechanics. The main idea is to offer a game that motivates the designers and guides them toward the creation of MSGs that respect all the initial constraints. Table 1 presents the design constraints for Echologia's botanical MSGs, and how we transformed them into game mechanics. Almost all constraints are related to contextual elements [START_REF] Chen | A survey of context-aware mobile computing research[END_REF]: user context, physical context, time context and computing context.

Table 1. From design constraints to game mechanics

Constraints related to

MSG Design Constraints

Game mechanics for the meta-SG

Physical context

Echologia's visitors must start at the entrance of the park and finish at the exit and cannot wander outside of the path for security reasons.

The designers use a board that represents a map of Echologia with the location of its trees (Figure 1). The designers use pawns to simulate the way the players move along the path. They can propose situated game activities for the players by sticking post-its on the board.

Time context

Previous paper-based games used in the park show that players keep interest in the game if they have regular activities approximately every 10 minutes. If they have less, they lose interest and if they have more, the games seems too long.

The designers can move the pawns 10 steps along the path before they propose a situated game activity and write it down on a post-it. Each step on the map is the equivalent of one minute of walking. This number of steps is adjusted to the players' profiles.

Educational objectives

Echologia's MSGs needs to teach the players how to recognise trees and provide information about their remarkable characteristics.

At the beginning of the creativity session, the designers are given 4 educational inspiration cards, which they can use to find ideas of game activities related to recognising trees.

User context

Echologia's MSGs must be adapted to all the park's visitor profiles (grand-parents, children, adolescents, botanists, tech savvy...)

The meta-SG involves three groups of two designers. Each group is assigned a persona for which they need to design game activities. As shown in figure 3, each persona has its own list of expectations regarding the game and movement characteristics.

User context

Echologia's MSGs will be played by groups of friends or family members who came to the park to spend time together. It should therefore be designed in order to promote social interactions between players (e.g. collaboration, competition) and physically reunited them, at least every 30 minutes [START_REF] Syvanen | Supporting Pervasive Learning Environments: Adaptability and Context Awareness in Mobile Learning[END_REF].

All the pawns must regroup on three gathering points, marked on the board. At this point, the designers can rethink the game activities they proposed and adapt them in order to add interaction between the players. In addition, the designers are given 4 inspiration social cards and 4 inspiration game-mechanic cards that can help them imagine original game activities that promote social interaction.

Computing context

As part of a research project in computer science, the MSGs must integrate innovative technologies (i.e. augmented reality, GPS activities) At the beginning of the design session, the designers are given 4 inspiration technological cards.

Meta Serious Game rules

As shown in Figure 1, the meta-SG involves three couples of designers. Each couple is placed around a board representing the map of the Echologia Park. Each group is randomly assigned to a persona for which they need to design a game scenario. They are also provided with 16 randomly chosen inspiration cards (4 educational, 4 game mechanics, 4 social and 4 technological) to help them come up with game activities for their persona. The position of the personas is physically represented by pawns. The pawns all start at the entrance of the park and can move along the path of white boxes, until they reach the park's exit. The three groups of designers each take turns in moving their pawn and proposing a game activity by writing it down on a post-it. In order to enhance their productivity, a five minutes time limit was imposed to come up with a new activity. However, they could, at any time, come back on this activity in order to move it to another location or modify it. The meta-game ends when all the pawns arrive at the park's exit. The goal of the meta-SG is to play collaboratively in order to design MSG scenarios that meet the persona's characteristics and expectations.

Figure 1. Meta-SG setup

Board

As described above, the designers work on a board that represents the actual map of the park (Figure 1 and Figure 2). The board also indicates the position of trees along the path with a QR Code link to a website with information about its species. Several non-botanical points of interest are also indicated on the board such as the lake or an old lime kiln. The idea is to concentrate all the information the designers might need concerning the physical context on a single map.

Gathering points

Three gathering points are represented on the board (Figure 1 and Figure 2). These were placed, with the help of the park owner, in areas where visitors naturally take a while to rest (i.e. next to farm animals, next to the lake and at the picnic area). When all the pawns are on these gathering points, the designers can take the time to rethink the game activities they proposed and adapt them in order to add social interaction between the players.

Inspiration cards

As presented in the introduction, inspiration cards, such as the Jen.cards [START_REF] Serna | JEN. cards: un outil pour faciliter la conception collaborative de learning games[END_REF], are a good way of helping designers find new ideas of MSG activities and enrich the ones they have already thought of. At the beginning of the meta-SG, each group of designers is provided with 16 inspiration cards to help them come up with game activities. These cards are to be used as inspiration and not as an additional constraint. As suggested by the Jen.cards authors, we selected only the relevant cards for the ReVeRIES project. First of all, we selected 8 out of the 16 existing game mechanics inspiration cards (e.g. individual challenge, act collectively, negotiation). We also selected 15 out of the 24 existing technological inspiration cards (e.g. augmented reality, taking a photo, positioning on a map). We used all 7 social inspiration cards (e.g. individual, collective, cooperation). Finally, we created 11 custom educational inspiration cards that are meant to help the designers find ideas of situated game activities related to tree recognition. The content of these cards was based on a discussion we had with a university botanical teacher and a paper-based botanical SG she recommended [START_REF] Marzin | Recognized trees in primary school : the game situation « Florex » : report of innovation[END_REF] proposing activities such as the identification criteria for species, natural habitat of species or culinary properties of species.

Figure 2. Proposing a situated game activity on the board (close-up of figure 1)

As shown in Figure 2, the designers use a post-it to write down a situated game activity for their persona, and stick it next to the location where their pawn is. They can also staple the inspiration cards they used to the post-it. For example, in Figure 2, the designers used 4 inspiration cards to imagine the activity on the rosehip: one technological card (GPS), one game mechanics card (competition) and two educational cards (anecdote about species and culinary properties of species).

Personas

Each group of designers was randomly assigned one of the eight personas below. These personas represent plausible profiles of park visitors.

• • Aunty Susanne -35 years old -active et social Each of these personas also has movement characteristics. For example, the persona "The twins" can move between 15 and 20 steps per turn instead of 10 steps, like other personas. This is because we consider this type of player as active and therefore eager to run during the game. Each persona also has a list of expectations regarding the game. They are expressed as recommendations for the designer to use inspirations cards when creating the activities for this persona. For example, the persona "The twins" is considered to be solitary, meaning that twins like to be among themselves (Figure 2). In order to help designers in creating a game that respects the personas' center of interest, we also expressed them as recommendations for using educational and technological inspiration cards. For example, designers are urged to use several technological inspiration cards for the tech savvy personas and, on the contrary, use more educational inspiration cards, related to the culinary properties of species, for personas that are interested in botany.

Figure 3. Persona examples

The meta-SG rules and material presented above are the result of a first experimentation with six PhD students. This session allowed us to add several improvements to the initial meta-SG. For example, we simplified the educational inspiration cards by reducing the text. We also decided to add a timer of five minutes to encourage the designers to propose game activities, knowing that they could always alter them later.

Validation of the Meta-SG in Real Context

Experimentation Setup

The meta-SG described above was experimented with 17 designers during the first meeting of the ReVeRIES research project. Before starting the design session, we explained why we decided to use a meta-SG and presented its rules. We emphasized the fact that these rules could be ignored or altered at any time. The 17 participants were dispatched in three groups (A, B and C). Each group was composed of 5 to 6 participants, with at least one botanical expert and one learning game expert. The other participants were computer scientists and offered advice on new types of technology that could be integrated into MSGs (e.g. augmented reality) and guaranteed their technical feasibility. After 90 minutes of using the meta-SG, the designers were asked to present their scenarios in front of the whole group, for further discussions. The aim of the experimentation was to validate the fact that the meta-SG was beneficial for creativity sessions.

In particular, we wanted to make sure the game mechanics created an enjoyable design session and encourage the designer to participate. We also wanted to see if the meta-SG was productive and if the designed scenarios were compliant with Echologia's constraints. Finally, we wanted to make sure that the designers did not perceive the game mechanics as limitations to their creativity. In order to collect this information, we filmed the sessions to evaluate the participant's engagement, we analysed the produced MSG scenarios and handed out questionnaire to gather the designer's insight on each game mechanic. In the next sections, we discuss the results for each of these points.

Result Analysis

Lively Collaborative Design

The video analysis shows that the designers in all three groups were very engaged in the meta-SG (Figure 4). During the entire 90 minutes, they exchanged ideas and helped each other to design original game activities. The botanical experts were often solicited to give their insight on the characteristics of the trees that could be used for the activities. Likewise, the SG experts were asked for their opinion on what game mechanic seemed to be best suited.

Productive Design of Precise Scenarios

After 90 minutes of work, the designers had produced five complete scenarios (i.e. sequence of activities from the park's entrance to exit) and 3 scenarios for the first section of the path. In total, more than 32 game activities were defined. The designers also came up with general ideas written down on post-its and stuck on the side of the board. Consequently, we can conclude that the meta-SG was very productive. Several designers also expressed this feeling orally as shown by this quote of the park owner: "I found the idea very interesting and the design game was very productive". In addition, the designed scenarios were very precise and very close to a shape that can be implemented as such. The details provided for each activity allowed us to build a MSG model and implement it in an authoring tool prototype. This prototype will soon be tested by the park owner to validate the fact that he can create his own scenarios. Having participated in similar brainstorming sessions in the past, we are positive that such a level of detail would not have been obtained with a classic brainstorming.

Designers Perceptions of the Meta-SG Effectiveness

One of the important points that we wanted to validate during the experimentation was the fact that the game mechanics of the meta-SG did not constrain the designers in their creativity. In this section, we analyse the designers' answers to the questionnaire concerning each game mechanic.

Meta-SG rules -helpful but not enough time

Q1. Did the game rules (3 groups of 2 designers, 5 minutes to find an idea), seem beneficial for the design? Do you have any suggestions? Among the 17 designers, the majority (9/17) answered "yes", 7 answered "not really" and only 1 answered "no". These quotes illustrate the main feeling: "Organisation a bit complicated at the beginning but useful for the design process"; "I would have been completely incapable of finding any ideas without being guided". However, almost all the designers suggest to increase the 5 minutes delay to come up with an idea.

Board -tree position and points of interest were very useful

Q2. Did the board (real map of the park, tree position and QR Codes), help you to find ideas or, on the contrary, limit your imagination? Almost all of the designers (14/17) answered "yes", 2 answered "not really" and only 1 answered "no". However, the designers' comments indicate that the QR Codes were used very little. On the one hand, as we expected, the designers preferred asking the botanist in their group for information about the trees. The real map of the park and the position of the tree, on the other hand, seemed very helpful to imagine game scenarios.

Personas -only the name and description were useful Q3. Did the persona (description, movement characteristics and list of expectations regarding the game) help you imagine activities that are adapted to the various player profiles or, on the contrary, constrain you? A large majority of the designers (11/17) answered "yes", 5 answered "not really" and only 1 answered "no". The designers' comments indicate that only the name and the two words that described the personas were useful. The movement characteristics and the expectations regarding the game seemed too constraining.

Gathering points -not really relevant to the designers Q4. Did the "gathering points" help you design a collaborative SG or, on the contrary, constrain you?

The answers to this question show that the designers had mixed feelings about this game mechanic. Out of 17 designers, 5 answered "yes", 5 answered "not really", 2 answered "no" and 5 didn't answer this question because they did not get far enough in the game to use it. Here are two quotes that illustrate these opposite point of views: "Yes, because it allows the family to share their gaming experience, count points if necessary and take off for new activities"; "No, they are quite constraining. I believe that each player feels like progressing at their own pace and imposing these gathering points seems complicated". The analysis of the MSG scenarios also showed that one group decide to move these gathering points a few boxes away because it was more convenient for the scenario.

Inspiration cards -good for inspiration but too numerous

Q5. Did the inspiration cards help you in finding ideas? Among the 17 designers, 9 answered "yes", 2 answered "not really", 6 answered "no". Mainly, the designers found that "the cards were very useful to find new ideas or complete an existing idea" however, "there were too many cards to look at".

Conclusion and Perspectives

In this article, we present meta-SG: a board game that helps designers come up with a large variety of MSG (Mobile Serious Game) scenarios in the early phases of a project. This meta-SG was designed in such a way to embed the numerous constraints of MSG design. In particular, the physical and time constraints related to the MSG's context of use, were embedded into the game's board and rules. Our hypothesis was that the use of such a meta-SG would encourage collaborative and productive interactions between SG experts, pedagogical experts and field experts, who are familiar with the location to which the MSG should be adapted. In addition, we hoped that by transforming the constraints of MSG design into game mechanics, these would not be perceived as limitations to the designers' creativity. Meta-SG was tested during the initial creativity session of a research project. The aim was to help 17 experts in SGs, botany and natural park owners to come up with a large variety of activities for a natural park. The hypothesis was validated: in 90 minutes, the designers came up with more than 32 detailed game activities that were compliant to the contextual constraints. In addition, a questionnaire confirmed that the designers enjoyed the meta-SG and did not feel limited by the constraints related to MSG design. Even though meta-SG was designed for a specific SG, we believe the method, we used to transform SG design constraints into game mechanics, are relevant for MSGs in general. For instance, the use of a map that indicates all the potential points of interest and accessible zones, can always be useful for designers. The use of paws, to materialize the player's position on the map, also seems like a valuable tool. The movement constraints (i.e. designers can move their pawns n steps before they propose a situated game activity) can also be adapted to the scale of the map. The other game mechanics should be adapted to the specific constraints of the MSG that is being designed. The meta-SG concept does have its limits. First of all, the preparation of the meta-SG material is quite time consuming. In particular, we spent a full day visiting the park and identifying all the potential points of interest to create the board. However, we believe this would have been a necessary step, whatever the method used for the creativity session. The other limitation is the fact that the designers need some time to get familiar with the meta-SG rules and the map before they actually start producing ideas. Our experimentation showed that the designers started writing on post-its after about 15 minutes, which seems reasonable. As researchers in game based learning, we can only regret the fact that we do not use games to enhance our own creativity sessions and conferences. Meta-SG is a first step towards this objective. Our experience with meta-SG also brought to light another positive effect of using games in the context of interdisciplinary projects: the non-SG specialists, involved in the project, were able to experience the power of SGs for themselves. This experience helped them understand the benefits of using SGs for the project. In the future, we intend on experimenting further by integrating game mechanics to the MSG authoring tool, adapted to the designers' profile.

  Grandma & Grandpa -80 years old -botanist and social • July & Juliette -18 years old -tech savvy and social • The children -8 years old -easy activities and need to be accompanied • Mario -26 years old -botanist and competitive • Mom & Dad -40 years old -cook and altruist • The twins -14 years old -active and solitary • Peter -20 years old -tech savvy and solitary

Figure 4 .

 4 Figure 4. Creativity session with the meta-SG and outcome

http://www.reveries-project.fr/

http://www.echologia.fr/

Aknowledgement

This work is supported by the French National Agency for Research with the reference ANR-15-CE38-0004-01 (ReVeRIES project). We also thank all the members of the project who participated in the creativity session, and took the time to answer our questions.


Iza Marfisi-Schottman

Pierre-Yves Gicquel
email: pierre-yves.gicquel@univ-lemans.fr

Aous Karoui
email: aous.karoui@univ-lemans.fr

Sébastien George
email: sebas-tien.georges:@univ-lemans.fr

From Idea to Reality: Extensive and Executable Modeling Language for Mobile Learning Games

Keywords: Mobile Learning Game, Game-Based Learning, Serious Games, Modeling Language, Scenario 1

Mobile Learning Games (MLGs) show great potential for education, especially in fields that deal with outdoor learning activities such as archaeology or botany. However, the number of MLGs currently used remains insignificant. This is partly due to the fact that the current authoring tools are based on modeling languages that only allow creating very specific and rigid types of MLGs. In this paper, we therefore propose an extensive modeling language for MLGs. This model was designed, with the help of botanical experts, in order to cover the variety of MLG types they would like for their field trips. This modeling language uses highlevel concepts, such as game activities and points of interest on a map that can therefore be used by teachers in any domain. Finally, we discuss how scenarios, described with this language, can be automatically transformed into executable web applications.

Introduction

Mobile Learning Games (MLGs) have proven their efficiency in various domains of education. Gaius' Day, for example, is used by history teachers, during archaeological outings Egnathia in Italie [START_REF] Ardito | Enriching Archaeological Parks with Contextual Sounds and Mobile Technology[END_REF]. Frequency1550 is used to teach high-school students about history in medieval Amsterdam [START_REF] Huizenga | Mobile game-based learning in secondary education: engagement, motivation and learning in a mobile city game[END_REF] and Skattjakt is another historical MLG used during the visit of a Swedish castle [START_REF] Spikol | Exploring Novel Learning Practices Through Co-Designing Mobile Games[END_REF].

However, even though MLGs show great potential, very few are actually used by teachers. Yet, there are several authoring tools that enable teachers to create their own MLGs without any computer skills. Why aren't these tools more used by teachers?

In this paper, we unravel the mystery by analyzing the needs of a group of botanists, who wish to create MLGs for a natural park. This work is part of the ReVeR-IES 1 project, which aims at using mobile technologies to help humans recognize the trees in a fun and motivating way. In the following section of this paper, we present a design experiment where botanist and learning game experts design MLG scenarios. We then use current authoring tools to implement these scenarios. Our conclusion is that state of the art authoring tools do not allow to express these scenarios. From then, we introduce the ReVeRIES modeling language.

2

What Needs for Authoring Situated Learning Games?

Designing Mobile Learning Games for a Natural Park

In this section, we try to identify why the existing authoring tools do not seem to be adapted to the needs of teachers and experts who wish to design MLGs. In order to do so, we organized a creativity session with a group of botanists and learning games experts who wish to create MLGs for the visitors of the Echologia 2 natural park. This creativity session, described in detail in [START_REF] Marfisi-Schottman | Meta Serious Game: Supporting Creativity Sessions for Mobile Serious Games[END_REF], resulted the production of eight MLGs.

Fig. 1 Creativity session, with a map of the park, for designing MLGs

Because of the limited space of the article, we will not describe each of these scenarios, but rather their main characteristics. First of all, the designers described the MLGs as a sequence of situated game units. We deliberately chose the term "unit" because the content of each unit formed a coherent set of activities aimed at teaching the characteristics of a plant. These game units are also "situated" because they are composed of activities that can only be done in the vicinity of this real plant. As illustrated in Fig. 1, each game unit, represented by a post-it, is physically located on a map and linked to objects of interest (botanical or non-botanical) alongside the path. Most of the game units were composed of an activity that consist in finding the point of interest (i.e. the plant or a group of plants) and one or several activities that are done once they are on site. Several MLGs also integrated forms collaboration between the players of a same group.

The goal of this creativity session was to determine the types of MLGs fields experts in botany would potentially like to create for their educational outings. It is therefore important to take into consideration the fact that the Echologia park is quite particular in the fact that the visitors are forced to walk along a simple path for safety reasons. This physical limitation resulted in the fact that all the MLGs designed for the park have strictly linear scenarios. In other words, the game units are done one after the other. If the MLGs were designed for an open natural park, some of them would probably have emergent scenarios in which the game units are triggers when the players are physically in the vicinity of the point of interest. This is often the case 2 http://www.echologia.fr/, visited in April 2016

for MLGs that offer interactive educational walks through cities or archeological sites. Another possibility is to design the scenario as an activity hub for which all the game units are available from the beginning and the players choose in witch order they want to do them. This is for example the case for Florex [START_REF] Marzin | Recognized trees in primary school : the game situation « Florex » : report of innovation[END_REF], a paper-based game used in primary school, in with the players are given exercise sheets, in relation to six specific trees in a public park.

Limitations of Existing Authoring Tools

After collecting eight scenarios designed during the brainstorming session, we tried to create these MLGs by using the existing authoring tools. First of all, let us note that we could only find two authoring tool specifically dedicated to MLGs: Aris and AR-Learn. We therefore extended our state of the art to authoring tools designed for mobile games (FuretFactory) and for educational mobile applications (mLearn4web). In the following section, we describe the limitations we encountered with each of these tools when trying to implement the eight scenarios designed by the botanists. Aris3 [START_REF] Gagnon | ARIS[END_REF] is a very rich tool but is extremely complicated to use. The main reason that makes it difficult to create game units is the fact that the model implemented by Aris is based on low level items. In other words, the user needs to create a multitude of low level items (text, quests, scenes, buttons, items for scoring and resources) and link them together with locks and triggers.

ARLearn4 [START_REF] Ternier | ARLearn: Augmented Reality Meets Augmented Virtuality[END_REF] is as complex to use as Aris. The authors of this tool actually recommend an "assistance phase" during which the teachers' scenarios are formalized and entered into the authoring tool by computer scientists.

FuretFactory5 , on the contrary, is very easy to use. In just a few minutes, the ergonomic user interface allowed to create simple situated activities linked to a point on a map. An important limitation is the fact that the scenario is always linear (i.e. one game unit after another) and do not support collaboration between players.

We can conclude that the existing tools are either not adapted to the type of MLGs teachers want, or too complex to use. In the next section, we propose a high-level modeling language that matches the natural concepts used by teachers. We then explain the work in progress to develop a simple authoring tool, based on this modeling language, which will allow teachers to create their own MLGs.

ReVeRIES Model: High-Level Modeling Language for Mobile Learning Games

As we have seen during the analysis of the existing authoring tools, the difficulty is to create a modeling language that offers high-level concepts, similar to the natural concepts used by teachers, and that is rich enough to adapt to various types of MLGs.

Fig. 2. ReVeRIES modeling language for Mobile Learning Games

In order to do so, we propose the ReVeRIES modeling language, partially depicted in Fig. 2. First of all, this modeling language integrates the concepts naturally used by designers during their MLG creativity session. Indeed, the central concept of the modeling language is the SituatedGameUnit that is linked to a Point Of Interest (POI) on which the game unit takes place. We can point out that this POI is a circular zone that can contain zero, one or several objects of interest (e.g. plants). The game unit is composed of:

 a trigger that starts the game unit (end of another game unit, when the player asks for it or when the learners is in proximity with a POI);  a clue to help the player find the POI. This clue can contain resources (text, pictures and multimedia), various guidance functionalities (showing POI marker on the map or GPS, beeper or vibration guidance). The teachers can also add extra clues that can be "bought" by the players in exchange for points. It also has a form of validation to determine that the player has arrived at the POI and can therefore start the on-site activities. This validation can be done with GPS (the learner must be in the geographical zone of the POI), by scanning a QRcode on the POI or by using an external specific system, such as Folia 6 , to prove that the learner has found the right tree species;  a reward for finding the POI (items for the inventory or points);  zero, one or several OnSiteActivities that are meant to be done at the POI.

These activities are composed of resources (text, video, augmented reality, situated chat), tasks (take a photo, collect items, compare objects, describe an object or answer a question). They also contain rewards for succeeding in the activity (item for the inventory or points);  a pedagogical conclusion that appear when the learner signals the end of the game unit. This is the perfect place for the teacher to underline the knowledge freshly acquired by the learner. A MobileLearningGame is composed of several SituatedGameUnits. It also has:  a type that determines the way these game units follow each other. For a linear scenario (e.g. treasure hunt), the game units are chained up, one after the other, meaning that the end of a game unit (completion status changed to "finished"), triggers and the clue of the next unit. For an emergent scenario (e.g. interactive walk), the clue for a unit is triggers when the player is physically the vicinity of the point of interest on which the unit takes place. Finally, for an activity Hub (e.g. geocaching or Florex [START_REF] Marzin | Recognized trees in primary school : the game situation « Florex » : report of innovation[END_REF]), all the clues of the units are given at the beginning of the MLG and the players can therefore decide the order in which they want to do them;  an inventory that contains all the virtual items earned as rewards (e.g. virtual objects, information sheets);  a score that keeps track of the points earned by the player;  a map of the geographical zone where the MLG will take place and can be viewed by the players at any time. The teacher can also choose to show the player's position and add another map layer in order to have a personalized map (e.g. map of Echologia park). The map also contains several points of interests (POIs) that can be shown or hidden depending on the time of MLG. In order to encourage collaborative behavior, the ReVeRIES modeling language also allows teachers to send rewards, earned during the game, to the inventory of another persona of the same group.

Conclusion

In this paper, we present the ReVeRIES modeling language for creating Mobile Learning Games (MLGs). This language was designed with the help of field experts in botany, but is generic enough to be used in other fields. This language fulfills a gap in the existing MLG authoring tools that are either too complex or too specific to allow teachers to use them.

We transformed each of the classes in the ReVeRIES model into a web component. For the time being, it is possible to create instances of each class by using an html tag. For instance, one can create an OnSiteActivity by using the <on-site-activity> tag. Each of these components takes parameters defined by the user, for instance in the case of a MCQ activity, the component takes the questions, possible answers and correct answers as parameters. These parameters are then used to instantiate the components on the web page. We are currently developing an authoring tool prototype that will allow non-computer scientist to create these instances without having to manipulate html. We are now in a phase of internal testing of the prototyping tools, and we plan to test them with field specialists soon. In future work, we will focus on automating the trace generation and processing to obtain feedback on the user activity. We will also work on defining MLG patterns that could provide a basic high-level succession of activity in a learning situation.

  Schottman, Pierre-Yves Gicquel, Aous Karoui and Sébastien George « From Idea to Reality: Extensive and Executable Modeling Language for Mobile Learning Games », Presented at the SemWebPro professional Conference, 21 November 2016, Paris, France.

	Iza Marfisi-
	1	http://www.reveries-project.fr/, visited in April 2016

http://arisgames.org/, visited in April 2016

http://portal.ou.nl/web/arlearn/, visited in April 2016

http://www.furetfactory.com/, visited in April 2016

https://itunes.apple.com/fr/app/folia/, visited in April 2016

Acknowledgments

This work is supported by the French National Agency for Research with the reference ANR-15-CE38-0004-01 (ReVeRIES project).