José L González Sánchez

Rosa M Gil

Francisco L Iranzo

Gutiérrez Vela

R M Gil Iranzo

F L Gutiérrez Vela

Enriching Evaluation in Video Games

Keywords: Playability, UX Evaluation, Emotions, Cross-Cultural Factors

de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

Introduction: Playability and UX in Videogames

Player eXperience (PX or User Experience in Video Games) depends not only on the product itself, but also on the user and the situation in which he or she uses the product [START_REF] Law | Understanding, Scoping and Defining User Experience: A Survey Approach[END_REF]. Due to the nature and design of videogames, user experience is enriched by recreational, cultural, and other subjective factors that make analysis and evaluation difficult using traditional methods commonly used in interactive systems Playability is a term used in the design and analysis of video is a live topic in the scientific community; it has been studied from different points of view and with different objectives. A comprehensive source of the most important references about playability and user experience in video games research works can be found in [START_REF] Isbister | Game Usability: Advancing the Player Experience[END_REF][START_REF] Bernhaupt | Evaluating User Experience in Games: Concepts and Methods[END_REF]. In this work we use the Playability Model to characterize the PX in Video Games, which attempts to unify the playability characteristics mentioned in the previous references [START_REF] González Sánchez | From Usability to Playability: Introduction to Player-Centred Video Game Development Process[END_REF][START_REF] González Sánchez | Playability: How to Identify the Player Experience in a Video Game[END_REF]. This model proposes the following attributes for defining the degree of PX: Satisfaction, Learnability, Effectiveness, Immersion, Motivation, Emotion and Socialization. Playability is defined as: "a set of properties that describe the Player Experience using a specific game system whose main objective is to provide enjoyment and entertainment, by being credible and satisfying, when the player plays alone or in company", Also, Playability represents the degree to which specified users can achieve specified goals with effectiveness, efficiency and, especially, satisfaction and fun in a playable context of use.

The importance of the hedonic UX factor in video games justifies the need to enrich video game evaluation methods and game metrics with hedonic properties in order to analyze the degree of experience according to a social and cultural background. In this paper we use the concept of Playability [START_REF] González Sánchez | From Usability to Playability: Introduction to Player-Centred Video Game Development Process[END_REF] as a measure of PX with the objective of performing an analysis based on "rich" evaluation, guided by facets of Playability. The aim is to enhance the overall game experience by completing information about the PX and determining which video game elements have more influence on the final experience through the emotional response, playability factors and social and cultural background. To illustrate these objectives we present a practical example of how to evaluate the PX by obtaining pragmatic and hedonic information about it and determining which game elements have more influence on the overall experience. To achieve this, we present an evaluation methodology which allows us to easily and cost-effectively perform a quantitative /qualitative and pragmatic/hedonic Playability analysis to apply it in video game playable prototypes in order to improve the overall experience during an agile video game development process.

Practical Example of Rich Evaluation in Video Games

To illustrate how the UX in video games can be evaluated we performed a videogame analysis taking into consideration the following objectives: analyze quantitatively/qualitatively the degree of PX in an easy and cost-effective manner; test the effect of different video game elements on the overall PX and complete the functional assessment and objectives of PX with hedonic evaluations (emotional response or social/cultural influence). The evaluation of playability was carried out in a laboratory, in order to observe how people actually play a game. The evaluation was divided into four stages. Pre-Test: Questionnaires and a short test to obtain information about player profiles. These were completed with emotional information and multicultural background influences. Test: We collected information in real time about player experience while users played a video game. We used observation techniques to measure facial and corporal expressions or biometric constants. Post-Test: We gave players different questionnaires and interviews to complete with information, especially subjective information related to hedonic properties (hedonic properties are a crucial factor in motivation, emotion and satisfaction attributes). Facets of Playability guided these questionnaires. Reports: We obtained a number of reports about the PX with information about which playability attributes had more influence, or which type of elements were more valued by the players. We also obtained special emotional information and cultural information using Emocards (Emontional cards/emoticons). The game chosen as an example for evaluation was "Castlevania: Lords of Shadow" by MercurySteam and Konami. To obtain the maximum information about UX we used different player profiles: "expert" (a person who is a good player, knows the game platform perfectly and is comfortable with difficult game challenges) and "casual" (a person who plays infrequently and looks for quick entertainment). The experiment involved the participation of 35 student volunteers from different degrees courses students at University of Lleida, Spain.

From the Pre-Test, we were able collect information about the profile of participants using multimedia questionnaires (images, pictures, music, videos, etc.). The most significant results about Pre-Test: The majority of participants were male (75%) between 19 and 22 years old (90%). They were considered to be casual players (play approximately 5 hours per week, and have experience of only one games console or a mobile phone). They had knowledge of different gaming platforms, including a mobile and a desktop platform (90%). The preferences for different game genres were: adventure (≈60%) and fighting (≈30%). 87% preferred to play in company. To identify emotional state, we reproduced a fragment of game OST (Original Sound Tracks). For 83% the music inspired "action" and made the user feel "energetic". In analyzing the adequacy of the game hero and the context of the video game, 77% of students said that hero transmitted the feeling "honest", 43% reported that the most valuable characteristic was the eye expression and 15% said the face. These factors represent hedonic properties that produce better immersion in the video game and socio cultural background influences.

During the Test, users played the videogame. Their facial and body expression was recorded and their heart rate monitored [START_REF] Isbister | Game Usability: Advancing the Player Experience[END_REF][START_REF] Bernhaupt | Evaluating User Experience in Games: Concepts and Methods[END_REF][START_REF] De Lera | Ten Emotion Heuristics: Guidelines for Assessing the User"s Affective Dimension Easily and Cost-Effectively[END_REF]. The aim was to detect visceral and emotional reactions occurring during the interaction process. With the arrival of challenges at the climax of the level, stress increased, provoking surprise and agitation in the player (lifting of the eyebrows, ≈94%). The stress caused by the challenges increased the player"s concentration. Players pressed the pad quicker and more violently (≈89%) than at the beginning of the game. At the climax of the level, two types of strategies were detected: a defense strategy, which was adopted by 100% of female users and 25% of men, who were intimidated by the game enemies and natural catastrophes. However, 75% of male users preferred a direct and violent confrontation. In both cases the degree of immersion was high, a factor, which was indicated by the increase in heart, beats per minute (≈18bpm at the climax of the level). Finally, stress became satisfaction, which was expressed as a slight smile or slight gasp (≈82%). It is interesting to note that the strategy depends on cultural factors such as gender and other factors, which may be related to the survival instinct of the user when faced with real challenges.

At the Post-Test we used informal interviews and questionnaires to obtain information about the player experience. The questions and heuristics are designed to extract information about the pragmatic and hedonic PX dimensions. This result was obtained thanks to the relation to the Playability Model, Facets and design of questionnaires [START_REF] González Sánchez | Análisis y Diseño de la Experiencia del Jugador en Sistemas Interactivos de Ocio Electrónico[END_REF]. One of the clearest results was that players were happiest with the game. This was reflected in the high values scored for the interactive facet, and ease of use of game controller (see learnability attribute). The positive result for "casual" players meant a negative experience for "expert" players, due to the excessive ease of play. Using the Emocards, we are able to analyze factors that are difficult to assess objectively using a number on a scale of values. However, at the same time, players are able to easily identify the emotional impact they have felt. Post-Test results reaffirm the positive feedback from users with regards to the setting and context as well as sound effects and music in general (high level of satisfaction, mainly characterized by a state of pleasure, which varies between excitation and neutral state). On a global level, the UX results were very positive, and the game satisfied players. From the results, we consider that enriching the PX analysis with multicultural and emotional factors (hedonic properties) helps us to establish information about player preferences and likes. The techniques demonstrated in this work can assist in the improvement of a video game as a product by enhancing the final experience, where the cultural or emotional impact can influence how a game should be designed or modified according to different player profiles or the market in a cost-effective manner.

CONCLUSION

This work reflects the importance of analyzing the experience that players have with video games in a pragmatic and hedonic way. Understanding and evaluating the user experience in video games is important for developing more efficient and successful products in terms of entertainment where cultural influence and emotional impact are crucial properties. To acquire more information about the player experience, we propose the enrichment of tests with hedonic factors (techniques of emotional design and cultural analysis) to increase the efficiency of questionnaires and heuristics. An example of this includes the use of Emocards, tracking the player response in real time, and measuring biometric constants. The measurement and analysis process is considered to be easy and cost effective to perform, thus making it appropriate for agile development based on playable video game prototypes. Through a practical example, we have demonstrated the importance of this kind of evaluation for the development of a product that can incite better experiences or specific experiences depending on the target market and it is advisable to use in every interactive system. As a future work, user mental model will be incorporated in the evaluation process.

Acknowledgments

This research is financed by: the Spanish International Commission for Science and Technology (CICYT); the DESACO Project (TIN2008-06596-C02) and OMediaDis (TIN2008-06228). Thanks to MercurySteam for the support in this work.


S Shyam Sundar

Saraswathi Bellur

Jeeyun Oh

Haiyan Jia
email: hjia@psu.edu

Calls for Interaction: The More the Better? User Experience of 3D Carousel and additional Interaction Techniques

Keywords: Interaction Techniques, 3D carousel, user experience, user engagement

We perform a user study to investigate the psychological consequences of adding interaction techniques to the interface. In a betweensubjects experiment (N = 143), we explore how (i) variations in sheer number of interaction techniques and (ii) addition of a novel technique, i.e., 3D carousel, influence the volume of users' actions, their memory, perceptions of interactivity, as well as their attitudes and behaviors toward a website. Power usage is examined as a potential moderator. First-cut findings from self-reports and log data indicate that the 3D carousel feature has a strong impact on user experience, both positive and negative. It also moderates the curvilinear effect of adding traditional interaction techniques to the interface.

Introduction

The range and richness of interaction techniques on websites offer users unprecedented variety and choice in interacting with an interface. For instance, the 3D carousel is fast becoming a common feature on websites, joining a growing cadre of interaction tools. However, little is known about the user experience created by these techniques. Does the increased number of calls for interaction necessarily enhance user experience? How does this feature combine with other techniques on the interface to influence higher-order outcomes? With this in mind, the purpose of our study is twofold: [START_REF] Sundar | Social psychology of interactivity in human-Website interaction[END_REF] to examine the effect of the addition of interaction techniques to user experience, their memory, attitudes and behaviors, and (2) to specifically explore the effect of the 3D carousel technique, and how it affects user experience?

Effects of Interaction Techniques

We define interaction techniques as any feature embedded in the website that offers various modes of interactions to users, based on the tripartite model of interactivity effects proposed by Sundar [START_REF] Sundar | Social psychology of interactivity in human-Website interaction[END_REF], which distinguishes between modality interactivity, source interactivity (customization) and message interactivity (contingent exchanges of messages). Interaction techniques come under the first of the three kinds of interactivity, in that they afford various modes of accessing information on an interface. Different types of interaction techniques add to the interactivity potential of the interface. However, literature suggests that the effects of interactivity are not always linear or positive. Empirical observations have revealed a so-called "interactivity paradox" [START_REF] Bucy | The debate[END_REF], with studies pointing to an optimal threshold beyond which the effects of interactivity diminish [START_REF] Sundar | Explicating web site interactivity: Impression formation effects in political campaign sites[END_REF]. Just what, how or when exactly is such a threshold reached remains an open question that is worthy of investigation. Aside from increases in the availability of interaction techniques, the presence of novel techniques such as the 3D carousel, with its characteristically revolving motion, invite active user action (e.g., flipping or swiping) that add to its interactivity potential. Its constantly rotating feature makes the 3D carousel playful, engaging and capable of providing rich forms of interaction, as claimed by Björkskog et al [START_REF] Björkskog | Mobile implementation of a web 3D carousel with touch input[END_REF]. However, such enthusiasm for it is yet to be validated empirically with users, especially when it coexists with other interaction techniques on the interface. Therefore, we experimentally examine how the addition of 3D carousel, combined with other interaction techniques, affects user experience and the degree of user engagement with a Web interface.

Method

We conducted a 4 (Click only, Click + Slider, Click + Slider + Drag, Click + Slider + Drag + Mouseover) × 2 (presence or absence of 3D carousel) between-subjects fullycrossed factorial experiment. Participants recruited from undergraduate classes (N = 143; 93 females) were randomly assigned to one of the eight conditions. Eight prototype websites were especially constructed for this experiment based on an online exhibition entitled "Guitar/Bass Timeline" [5]. Except for the number of interaction techniques employed, all eight versions of the prototype website shared the same content and page layout. We embedded the manipulation of 3D carousel in the homepage (Figure 1). Whenever participants clicked on a guitar in the homepage, the site played a brief audio-clip of a classic riff produced by that particular guitar/bass. In both conditions, clicking on one of the guitars took participants to the next layer of site content, which featured a slider (for going across a timeline), a drag feature (allowing users to drag a guitar-pick on the instrument for more information), and/or a mouseover function (for accessing embedded textual information in so-called "hotspots"). Examples of stimuli are accessible at <http://tinyurl.com/3f8ypmk>. The websites for all eight conditions were elaborately pretested for usability. Based on literature which identifies browsing as the quintessential interaction task [START_REF] Zhai | Improving Browsing Performance: A study of four input devices for scrolling and pointing tasks[END_REF], we instructed our study participants to browse the stimulus website fully and completely. To make the task as realistic as possible, no time constraints were imposed, nor were the participants told that their memory for site's content would be tested later in the study. All questions were measured on a 7-point Likert scale, except for recognition and recall memory measured through multiple-choice and open-ended questions. Power usage was measured via 12 items about the degree of participants' liking of technology and their extent of use [START_REF] Marathe | Who are these power users anyway? Building a psychological profile[END_REF] (α =.83). Perceived interactivity was measured by 3 items (for e.g., the degree to which it allows them to perform lots of actions) (α = .76) based on [START_REF] Kalyanaraman | The psychological appeal of personalized online content in Web portals: Does customization affect attitudes and behavior[END_REF]. Perceived ease of use was measured by 3 items (α = .74) adapted from [START_REF] Davis | Perceived usefulness, perceived ease of use, and user acceptance of information technology[END_REF]. Behavioral intention toward website was measured by 6 questions (α = .93) [START_REF] Hu | Effects of online health sources on credibility and behavioral intentions[END_REF]. We collected log data using jQuery to measure user actions (average frequency of page visits and average number of user interactions per hotspot).

Results

An interaction effect showed that the addition of interaction techniques to the interface served to enhance user perceptions of interactivity only in the absence of 3D carousel, F (3, 134) = 4.11, p < .01. The relationship between the number of interaction techniques and perceived ease of use assumed an inverted-U shape when the 3D carousel feature was present on the interface, F (3, 134) = 4.39, p < .01 (see Figure 2). The analysis of behavioral intentions (e.g., forwarding and recommending the site to others) yielded a similar inverted-U interaction, F (3,134) = 3.01, p < .05 (Figure 3). Taken together, the 3D carousel boosted perceptions of interactivity, so much so that it overrode common interaction techniques such as click, slider, and drag. It also stimulated user interaction. However, this appeal of 3D carousel came at a cognitive cost, degrading users' memory for audio that accompanied the guitars and inhibiting their tendency to visit the homepage. It negatively affected perceived ease of use and behavioral intentions when the study website was saturated with four interaction techniques, even when users reported that a site with 3D carousel was easier to use and were likely to recommend it. This parallels previous findings [START_REF] Wang | Designing a generalized 3D carousel view[END_REF] that the 3D carousel is more suitable for aesthetic appeal than task efficiency. In addition, more interaction techniques aided the information uptake for power users, encouraging us to consider individual differences relating to technology competency when predicting user experience with new as well as multiple combinations of interaction techniques.

Figure 1 .

 1 Figure 1. Homepage with 3D carousel vs. without 3D carousel

Figure 2 Figure 3

 23 Figure 2 Perceived ease of use (C: Click, S: Slide, D: Drag, M: Mouseover)

Acknowledgments. This research is supported by the U.S. National Science Foundation under Grant No. IIS-0916944 and the Korea Science and Engineering Foundation under World Class University (WCU) Grant No. R31-2008-000-10062-0.


Jose Ignacio Panach
email: jpanach@pros.upv.es

Nelly Condori-Fernández

Arthur Baars
email: abaars@pros.upv.es

Tanja Vos
email: tvos@pros.upv.es

Ignacio Romeu
email: iromeu@pros.upv.es

Óscar Pastor
email: opastor@pros.upv.es

Towards an Experimental Framework for Measuring Usability of Model-Driven Tools 1

Keywords: Usability, model-driven development, evaluation framework

According to the Model-Driven Development (MDD) paradigm, analysts can substantially improve the software development process concentrating their efforts on a conceptual model, which can be transformed into code by means of transformation rules applied by a model compiler. However, MDD tools are not widely used in industry. One of the reasons for this poor adoption is the lack of usability of MDD tools. This paper presents a framework to evaluate the usability of such tools. The framework will be used as a basis for a family of experiments to get clear insights into the barriers to usability that prevent MDD tools from being widely adopted in industry.

Introduction

MDD tools can offer many benefits for a software developing company: reduced costs, reduced development time, higher quality and higher customer satisfaction [START_REF] Selic | The Pragmatics of Model-Driven Development[END_REF]. However, the wide acceptance of MDD is not yet a reality. One reason for this situation is the lack of usability of MDD tools. The main contribution of this paper is an empirical framework to perform a set of usability evaluations for MDD tools. By experimental framework we mean the definition of a process and the elements involved in it with the aim of performing evaluations unambiguously. The framework will be used to perform the evaluation of several MDD tools knowing clearly the required elements and the stages to perform the experiment.

Several authors such as Fiora [START_REF] Fiora | Automated Usability Testing Framework[END_REF] and Kostiainen [START_REF] Kostiainen | Framework for Comparative Usability Testing of Distributed Applications[END_REF] have proposed experimental frameworks for measuring system usability. If we focus our research on MDD tools, little work has been published about their usability. We can only find usability frameworks defined for evaluating usability in Computer Aided Software Engineering (CASE) tools in general, such as the work of Senapathi [START_REF] Senapathi | A Framework for the Evaluation of CASE Tool Learnability in Educational Environments[END_REF]. However, frameworks defined for CASE tools are not always valid for MDD tools. In contrast to conventional CASE tools that are oriented to software development based on design and programming, MDD tools have to cope with specific features where the modeling and the programming perspective become intertwined. MDD tools have as peculiarity that they have an underlying software delevopment method which must be easily understandable to the user. Studying related work, we conclude that more work must be done on the usability evaluation of MDD tools to become fully accepted in industry. The paper is divided into these sections: 2nd describes the framework, 3th applies the framework to a specific MDD tools, and 4th presents the conclusions.

Empirical Framework to Evaluate the Usability of MDD Tools

The empirical framework is composed of a usability evaluation model and an experimental process, which have been designed using Wohlin's proposal [START_REF] Wohlin | Experimentation in Software Engineering: An Introduction[END_REF]. The usability evaluation model identifies the most relevant elements for evaluating the usability of MDD tools (Figure 1). According to Figure 1, we aim to evaluate the usability of MDD tools by means of: satisfaction, efficiency and effectiveness, such as ISO 9241-11 proposes [START_REF]ISO 9241-11 Ergonomic requirements for office work with visual display terminals[END_REF]. In summary, this model represents: the method that underpins the MDD tool, the end-user features, and the activities that the end-user will execute in the experiment. Classes with a grey background represent elements that can be changed and controlled in the experiment and classes with a background of diagonal lines represent elements that can be quantified with one or more measures.

The experimental process focuses on the stages that compose the process to perform the usability evaluation according to the usability model. There are four stages [START_REF] Wohlin | Experimentation in Software Engineering: An Introduction[END_REF] (Figure 2): (1) Definition: This determines the foundation of the experiment; (2) Planning: This specifies how the experiment is conducted. (3) Operation: In this step, the researcher performs the experiment and collects the needed data; (4) Analysis: In this step, the researcher interprets the experiment data. Each one of these stages is divided into substages, such as Figure 2 shows. This section explains the usability evaluation that we performed with the proposed framework applied to an MDD tool called OLIVANOVA [1]. We focus our study on effectiveness and efficiency, relegating the satisfaction to a future experiment. Next, for space reason, we detail only some elements that compose the Planning stage (Figure 2): hypotheses, variables and participants. However, it is important to note that the Usability Evaluation Model (Figure 1) is instantiated throughout all the substages that compose the Definition and Planning stages (Figure 2).

We have one null hypothesis for efficiency and another for effectiveness: H 10 : When using OLIVANOVA for modeling tasks with different levels of complexity, the efficiency is the same independently of users' experience. H 20 : When using OLIVANOVA for modeling tasks with different levels of complexity, the effectiveness is the same independently of users' experience.

We have identified dependent variables and independent variables [START_REF] Wohlin | Experimentation in Software Engineering: An Introduction[END_REF]: Dependent variables: Efficiency and effectiveness. Efficiency was measured by task completion percentage in relation to the time spent to perform a task. Effectiveness is the level of completeness reached in every task. This variable was calculated by two measures: 1) the percentage of tasks carried out correctly; 2) the percentage of correctly performed activities that were carried out optimally (without any difficulty compared to experts).

Independent variables:

The level of complexity of the tasks, the modeling competence, and the level of experience using MDD tools. We used three groups of participants: Type I (Experts): Experienced using the evaluated tool. This group was composed of researchers of the ProS center of the Technical University of Valencia. Type II (Medium): Experienced using similar tools. This group was recruited from the regional Valencian public administration who are familiar with open source MDD tools like Moskitt [6]. Type III (Novice): No experience with the tool nor with similar tools. This group was composed of engineers from the Technological Institute of Computer Science who are familiar with Object-Oriented concepts but not with any modeling tool. We used four users from each group to work with a balanced number of users. Instruments used to perform the experiment can be found at [3]. Once the experiment was finished, we analyzed the results of the efficiency and the effectiveness. Efficiency was measured by task completion percentage in relation to the time spent doing a task. According to an ANOVA test, we reject the null hypothesis. However, if this analysis is carried out excluding the group of experts, there are no differences in the mean efficiency scores with the other two types of users. Effectiveness was measured in terms of modeling task completion percentage and percentage of correct tasks that were carried out optimally. With the ANOVA test, we found significant differences for both the tasks of medium level of difficulty and high level of difficulty in the three groups of users. Therefore, we conclude that H 20 is not satisfied.

Conclusions and Future Work

This paper proposes an empirical framework to evaluate the usability of MDD tools. The framework aims to replicate the usability evaluation of MDD tools in similar conditions. With the purpose of evaluating our framework; it was applied to a MDD tool called OLIVANOVA. The results of the evaluation demonstrate that changes must be applied to OLIVANOVA to improve the users' effectiveness and efficiency. As future work, we want to repeat our usability test with more users and considering the user's satisfaction. Moreover, we want to assess the framework with other MDD tools different from OLIVANOVA.

Fig. 1 .

 1 Fig. 1. Usability Evaluation Model

Fig. 2 .

 2 Fig. 2. Process to evaluate usability

This work has been developed with the support of MICINN, GVA and ITEA

call under the projects PROS-Req (TIN2010-19130-C02-02), ORCA (PROMETEO/2009/ 015) and UsiXML (20080026).

Jose Ignacio Panach1, Nelly Condori-Fernández2, Arthur Baars1, Tanja Vos1, Ignacio Romeu1, Óscar Pastor1

DEFINE


Nsemeke Ukpong
email: n.i.ukpong@student.tue.nl

Privender Saini
email: privender.saini@philips.com

Abdullah Al Mahmud

Using Availability Heuristics in Game Design to Introduce Children to Energy Sufficient Behaviours at Home

Parents looking to foster more energy sufficient behaviours in their children struggle to have their child maintain these behaviours unsupervised. Our research indicates that in order for the child to maintain these behaviours, s/he must perceive him/herself as an eco conscious individual. We propose that increasing a child's ability to firstly recognise eco-friendly behaviours and secondly, recollect them, is likely to yield a greater affinity for habitual energy sufficient behaviours. This paper describes a first prototype game, whose interface employs availability heuristics and other persuasive design elements to achieve this goal. 1. Chooses period of day 2. Reads descriptions 3. Makes a guess

Introduction

The negative impact of increasing global energy consumption on our environment is becoming alarmingly apparent [START_REF] Ehrlich | Impact of Population Growth[END_REF], [START_REF]World Energy Outlook: Fact Sheet[END_REF]. It is recognized that the problem has to be tackled and from multiple angles, for example recycling schemes for plastics and glass and energy efficiency labels for electrical appliances [3]. We describe the usercentred design of a dedicated system aimed to foster energy sufficient behaviours at home in children aged between 8 and 10 years. Our user group is inspired by the idea that knowledge and skills practiced in childhood, will lead to eco-friendly decision making in adulthood.

To gauge the desirability of such a system, we conducted an online survey involving 25 parents. The survey outcomes indicated that parents would indeed welcome more energy sufficient behaviors in their children. In addition, it revealed that the challenge lies in getting the children to adopt these behaviors unsupervised. This is thus the focus of the system explained within this paper.

Design: approach and concept

Once established, human behaviors generally take a long time to change. Literature research into this area indicates that there is a feed-forward loop between attitude and self perception [5]. According to Cornelissen et al. [5], self perception is dependent on the availability heuristic of specific behavior-related information.

In order to gauge the connection between children's attitude and their knowledge of energy sufficient behaviors five children of ages between 8 and 10 were interviewed. The interviews were conducted at 2 different international primary schools in the Netherlands. During the interviews, a quiet location at the child's primary school was chosen and he or she was asked a set of pre-made questions in a conversational manner. The questions were designed to gather information regarding the relation of the following four key areas: knowledge, activities, communication and attitude, and energy sufficiency.

Our findings showed that the children were aware of direct actions such as switching off electrical appliances such as lamps, televisions and computers. Upon probing, the children were able to identify further energy saving actions such as closing doors or dressing warmly in the winter. We observed the need for probing, and the outcomes as an indication that there were likely to be further actions which children carry out at home but which, due to their indirect relationship with energy, were not readily associated with eco-friendliness. This observation inspired the primary function of the proposed system: to increase the children's ease of retrieving pro-ecological actions.

The envisioned design is an intelligent system that facilitates a game employing role play to challenge children to independently execute character-specific energy sufficient actions during their normal daily routine. These actions are monitored by the system and feedback that is both stimulating and educational is provided in a manner that reinforces the child's ability to associate the action with eco-friendliness. It is our expectation that long term play of this game, will strengthen the child's long term perception of him/herself as an eco-conscious individual.

as well as the profile of a child on a specific 'Character Card'. The objective of the game is to identify the 2 correct AESBs.  Activities are mapped to the branches of an 'Activity Tree' visualization. This mapping has the purpose of communicating the impact that different behaviors can have on the tree during a specific routine activity such as breakfasting. The tree communicates its health through its number of leaves and the brightness of its leaves.

To play the game, the child selects either to try an evening or a morning activity. Upon doing so, the timer starts and s/he is presented with the elements in stage 2 of Fig 1 . The child then selects and deselects the AESB as s/he sees fit, pressing the 'Check Guess' button when ready to test the guess. If the guess is correct, the timer stops, all the targeted leaves from dark green to bright green and a congratulatory message appears on the screen. If the guess is incorrect a message appears for a short period, informing the child of this, the child should then try again.

Scenario Evaluation

For the test scenario, 4 children aged between 9 and 11 were provided with a URL link to the game so that they could play it individually in their own homes. The children were instructed to play the game twice: once for the morning routine and once for the evening routine. Prior to playing the game, they were asked to read through a pre-test form presenting two lists of the same 13 energy impacting behaviors. Amongst these 13 were the AESBs presented in the game scenario. For one list, they were asked to select the behaviors which they thought best completed the following sentence: "When I want to save energy around breakfast time I can…"and for the second list, the following sentence was used: "When I want to save energy around relaxing time in the evening I can…" After playing the game once per period of day, they were required to fill in a post test form involving the same list and activity as the pre test form. Finally, the forms were sent via email.

Each behavior had a weighted value of 0, 1 or 2, depending on its suitability to the headline sentence. This weight was used to calculate the scores achieved by the children. The results showed a lack of improvement by 18 of the behaviors. Of this 18, 9 were negative results-i.e. the child selected the behavior in the pre test form but not in the post test form. The other 9 showed no change. Six out of the 26 available behaviors showed positive improvement. Four out of this 6 belonged to the morning activity. Child 1,2 and 4 showed an increase in their scores of percentages 12, 3 and 3 respectively. Child 3 showed a decrease of 3%.

The results showed that there was a marginal increase in the children's familiarity with AESB: with 3 out of the 4 children being able to identify AESBs more correctly than before. The children's remarks regarding the textual feedback in particular indicated that they understood the mapping between successful guesses and unsuccessful guesses. This indicated that the game had been successful in introducing the participants to AESB.

Discussion and Conclusions

We found that with a short test, we were able to increase the children's ability to identify more energy efficient behaviors than before. This is a promising finding, as it gives confidence in the potential impacts such a game could have.

This paper has made one major contribution towards the design of educational interactive systems for initiating behavior changes in children. We have shown with a first prototype game designed to present alternatives to habitual behaviors to positively influence a child's affinity to energy sufficient behaviors.

Further work could focus on extending the list of eco-friendly behaviors children could perform, and even have lists tailored to certain ages. In addition, more thought could be put in the 'Character Card's to appeal to children of various ages. Finally, a more robust and extended set-up would allow us to conduct a more thorough test regarding the potential of the game to add knowledge, and ultimately change behavior.

Fig. 1 .

 1 Fig. 1. Example outline of the game sequence supported by the interactive web-based prototype

Concept: implementation and evaluation

The system described in Fig 1 . implements 3 preliminary components identified as being the foundation of the conceptual model of the envisioned game. These components are 'Character Cards', an 'Activity Tree' and a list of 'Alternative Energy Sufficient Behavior' (AESBs). For ease of evaluation, it has been developed as an interactive web based interface. Our objective is not to test the 'real time' properties of the game but rather, if the enforced relationship between the 3 key components is suitable for increasing children's knowledge of AESBs. The relationships between the components are described below:  AESBs describe different energy sufficient behaviors that children aged between 8 and10 might carry out a specific activity during their daily (weekday) routine. They are presented in text format, in a list of 5. These five comprise of 1 energyneutral behavior, and 4 energy-impactful behaviors. Of these 4, only 2 are fitting to the persona of a 'Character Card'.  A 'Character Card' is an item depicting a child aged between 8 and10 who, due to his or her personality, is inclined towards specific AESBs. Of the five AESBs listed, only two correctly match both the activity presented by the 'Activity Tree',


Lucía Vera

Jesús Gimeno

Inmaculada Coma
email: inmaculada.coma@uv.es

Marcos Fernández
email: marcos.fernandez@uv.es

Jesus Vera

Gimeno

Augmented Mirror: Interactive Augmented Reality System based on Kinect

Keywords: Augmented Reality, Motion Capture, Virtual Characters

A bstract. In this paper we present a virtual character controlled by an actor in real time, who talks with an audience through an augmented mirror. The application, which integrates video images, the avatar and other virtual objects within an Augmented Reality system, has been implemented using a mixture of technologies: two kinect systems for motion capture, depth map and real images, a gyroscope to detect head movements, and control algorithms to manage avatar emotions.

Introduction

In the field of HCI, combining the real world with virtual information and introducing virtual characters interacting with a real audience are elements that add richness and complexity to presentations and public events.

In this context we have developed an Augmented Reality (AR) application that allows the audience to interact and talk with a virtual character through a large screen called augmented mirror. The avatar movements are controlled by an actor in realtime using a Motion Capture (MoCap) system. That avatar, together with video images from the real world and other virtual objects, are integrated in a system that also incorporates the voice of the character and the manipulation of virtual objects. In a review of the literature we find different MoCap systems used for the animation of virtual characters. The MoCap devices use different technologies to acquire positions. Thus, in Waldo C., a virtual puppet, a mechanical system was used to track body joint angles using an exo-skeleton structure [START_REF] Walters | The story of Waldo C. Graphic. Course Notes: 3D Character Animation by Computer[END_REF]. Other systems use electromagnetic sensors [START_REF] Huang | Interactive Demonstration of Pointing Gestures for Virtual Trainers[END_REF], or optical systems with markers and cameras. Finally, some use optical systems without markers using an image recognition algorithm to detect positions and movements [START_REF] Wren | Pfinder: real-time tracking of the human body[END_REF].

Within AR applications, MoCap devices are also used to control the interaction between the user and the virtual objects. Sometimes optical systems with markers [START_REF] Dorfmüller | Robust tracking for augmented reality using retroreflective markers[END_REF] are used to detect positions but, in other cases, more complex systems are utilized that are based on ultrasounds or inertial sensors that detects movements in a wide range of use [START_REF] Foxlin | Constellation: A Wide-Range Wireless Tracking System for Augmented Reality and virtual set applications[END_REF][START_REF] Vlasic | Practical motion capture in everyday surroundings[END_REF].

Aiming to achieve a system that captures the limited space and lighting conditions, including facial expressions and lip movements, we used a combination of technologies: a Kinect device for MoCap, a gyroscope for head movements, and a WiiMote with control algorithms for facial expressions. Moreover, it has been necessary to create an augmented video image blending the avatar and the real environment, using another Kinect depth map for that purpose. However, Kinect presents some restrictions that we have solved with different solutions described in the next section.

System description

The proposed system is composed of two main parts, called scenarios (see Figure 1). In the first one, the control scenario, the actor tracking is performed using a MoCap system. In the second one, the augmented scenario, the audience can interact with the avatar and other virtual objects. These two scenarios are connected using a Client-Server model, via an Ethernet connection, so that the avatar can be remotely controlled.

With regards to the control scenario, a number of input devices are combined into an enhanced MoCap system (see Figure 2) which serves the actor to control the avatar movements, facial expressions, lips movement and also some predefined virtual objects. Moreover, input data from these devices is received and processed by a server application to control the augmented scenario (the avatar and the virtual objects).

The main MoCap device is a Kinect camera that controls the avatar movement. By using OpenNI (Open Natural Interface) SDK, Kinect performs actor tracking in real time, with an 11 bones avatar structure (see Figure 1). In our system, this control was not enough to obtain a realistic avatar and, therefore the tracking was enhanced in 4 different ways: head orientation, lips movement while talking, facial expressions and automatic gestures (blink, hands, feet, etc.).

F ig. 1. General system structure (left); Kinect avatar skeleton (right).

Head orientation is estimated using a mobile phone attached to a cap. This can be achieved with an android application that computes heading, pitch and roll from the phone sensors data (accelerometer and compass) and send it to the server application through a Wi-Fi connection. This global information, referenced to the earth gravity and North Pole, is computed to calculate head orientation according to the actor orientation. For lips movement while talking with the audience, the actor is provided with a wireless microphone. An amplitude based algorithm has been developed to calculate, lips aperture values (horizontal and vertical), which simulates the real mouth movement while talking. A WiiMote is used to control avatar facial expressions and 3D virtual objects. The actor can easily choose the avatar facial expression, using the WiiMote buttons, from five different predefined emotions. In the same way, 5 virtual animated objects can be shown or hidden. Finally, other avatar movements are computed automatically. Blinking velocity is controlled depending on the selected emotion; hand and finger movements are calculated from the arm movement. All this information is sent to the augmented scenario in real time, making possible a live interaction between the real actor and an audience.

F ig. 2. Scheme of the overall application.

The augmented scenario is where the audience interacts with the avatar and the virtual objects via the augmented mirror. The audience can talk with the avatar or walk around him and the virtual objects while they can see themselves in a large LED screen (Figure 4). An important element of our augmented visualization is the correct occlusion between real and virtual information. This augmented images displayed on a 4x3 meter LED screen provide a more immersive multiuser augmented reality experience. A Kinect camera is used to capture the real image of the audience which is used in both scenarios. In the control scenario the real actor can see the audience to interact with them, while this image is merged with the avatar and the virtual elements to generate the augmented mirror image. The occlusion handling is implemented on a GPU shader, which takes the real image and the depth information captured by Kinect, mixing it with the virtual scene. The implementation of the augmented visualization is based on OpenSceneGraph, Cal3D and our own developed libraries. The avatar skeleton (see Figure 3), has been designed to perform all the gestures and facial expressions desired.

Conclusions

This paper has presented an augmented mirror where a virtual actor interacts with an audience. Kinect motion capture capabilities have been used and enhanced with other 3 input devices to perform a MoCap system which allows the actor to control the avatar movements, facial expressions, lips movement and also some predefined virtual objects. The system has been successfully used in a real marketing , where nearly 100 person enjoyed the augmented mirror experience.

F ig. 3 .

 3 Augmented mirror (left); avatar skeleton (right).


Josep Maria Brunetti
email: josepmbrunetti@diei.udl.cat

Information Architecture Automatization for the Semantic Web 1

Keywords: Semantic Web, Linked Data, Information Architecture, Usability, Accessibility, Navigation, Metadata

Our proposal is to develop generic Information Architecture components to facilitate publishing and browsing semantic data in the web, improving its usability and accessibility.

Introduction

Despite the Semantic Web was proposed ten years ago [START_REF] Berners-Lee | The semantic web[END_REF], it hasn't been until recently when it has started to become popular. In the last years, the amount of semantic data available in the Web has increased in a spectacular way, especially thanks to initiatives like Linked Open Data (LOD). The objective of this initiative is to motivate the publication of Open Data in formats that are more easily integrable, queryable and that facilitate its reuse. The cloud of interrelated and open datasets included in the LOD cloud has rapidly evolved, from the 2 billion statements and 30 datasets one year after its creation in February 2007, to more than 25 billion statements and 200 datasets in September 2010 3 .

The potential of this huge amount of data is enormous but in most cases it is very difficult for users to explore and use these data. The problem is that most of this data is available as raw data dumps or SPARQL [START_REF] Prud'hommeaux | SPARQL Query Language for RDF[END_REF] semantic query services, being it complicated to realise what the data is about, which are the main kinds of things, how are they interrelated, etc. Moreover, it requires some experience in Semantic Web tools and, in any case, the results are not very usable. Therefore, the challenge is to structure all this information making it more usable and accessible.

Information Architecture (IA) is a discipline that focuses its efforts in this problem, especially in complex systems and situations with great amounts of information. IA describes the structure of a website, how its information is grouped, navigation methods and terminology used. A good IA can improve the quality of a website and users can find more easily the information they are looking for.

The proposal of this project is to draw from the experience accumulated in the Information Architecture domain [START_REF] Morville | L: Information Architecture for the World Wide Web[END_REF] and adapt existing IA components to these situations with large amounts of heterogeneous semantic data. The rest of this paper is structured as follows. In Section 2 we present the state of the art and other approaches to this problem. Section 3 is about our proposed approach and in Section 4 we explain the methodology we will follow during this PhD and evaluation methods. Finally, in Section 5 we present our conclusions and future work.

State of Art

The best approach to make a semantic dataset more usable to a wider range of users is to use a Web data publishing tool or a Semantic Web browser, e.g. Disco [START_REF] Bojars | An Architecture to Discover and Query Decentralized RDF Data[END_REF]. These kinds of tools provide an HTML rendering for each resource in the dataset, listing all their properties and values. HTML pages are interlinked based on the connections between resources in the underlying dataset. However, this feature is only useful if the user has some a priori knowledge of the data structure. There is no way to get an overview of the kinds of resources in the dataset, e.g. person, address, etc.

Explorator [START_REF] Araujo | Experimenting with Explorator: a Direct Manipulation Generic RDF Browser and Querying Tool[END_REF] is another tool that makes it possible to browse a dataset combining search, facets and operations on sets of resources. However, it is also difficult for users to get a broader view on the dataset. Other tools also provide faceted views but not as a generic browser, i.e. just for a specific dataset like the case of the DBPedia Faceted Browser [START_REF] Hahn | Faceted Wikipedia Search. 13th International Conference on Business Information Systems (BIS'10)[END_REF] or \facet [START_REF] Hildebrand | /facet: A Browser for Heterogeneous Semantic Web Repositories[END_REF].

Consequently, existing tools make very difficult for users to explore a dataset, realize what kind of resources there are, what properties they have and how they are related.

Proposed Approach

As the volume of information in the Semantic Web increases, interacting with information becomes a more difficult task. To interact with these amounts of data, users use different ways or strategies depending on their goals.

Starting from the fundamental set of tasks for data analysis proposed by Schneiderman [START_REF] Shneiderman | The Eyes Have It: A Task by Data Type Taxonomy for Information Visualizations[END_REF], we have explored the most appropriate Interaction Patterns to perform these tasks in the context of the Semantic Web:

• Overview: the goal of this task is to get a full view of the entire collection.

We propose to apply the Global Navigation interaction pattern. In the context of IA it corresponds to navigation menus. • Filter: to select items of interest and filter out uninteresting items through exploratory search. The proposal is the Faceted Navigation pattern, which in the context of IA corresponds to facets.

• History: to keep a history of actions and support undo and replay actions. We propose to apply the Breadcrumb Navigation pattern. In the context of IA it corresponds to breadcrumbs. We have chosen these IA components because they are simple and very common in websites, so users are comfortable with them. Besides them, we are exploring other IA components such as sitemaps and search systems.

The drawback of all these IA systems is that they are quite expensive to develop and maintain, even more with the large amount of heterogeneous semantic data we are dealing with. Fortunately, when these IA systems are built on top of structured data and formal languages, it is possible to automate most of this development and maintenance work.

Concretely, the Semantic Web, with the use of ontologies and semantic languages like RDF, allows the automatization of these components. The Semantic Web provides methods and tools to model the Information Architecture for a domain with much more detail and in a formal way. It is possible to define concepts, properties and relations between them. This allows the use of automated tools to process these formal descriptions, create and maintain the Information Architecture.

The main goal of this PhD is to define a methodology and develop the necessary components to assist during the definition and maintenance of the Information Architecture of websites from a formal description of the site's domain. It is also intended, in parallel, to improve the usability and accessibility of the generated Information Architecture. By using these components, the final users will be able to easily explore semantic data, which at this moment is not usable and accessible for them.

Methodology and evaluation

The methodology to follow in this project is based on the MPIu+a [START_REF] Granollers | User centred design process model, integration of usability engineering and software engineering[END_REF] development process, which integrates the disciplines of Software Engineering, Human-Computer Interaction and Accessibility. Besides the traditional Software Engineering lifecycle, MPIu+a has two other main blocks, prototyping and evaluation, which are also two main parts of this project.

We plan to develop prototypes for each of the identified Information Architecture components, test and evaluate them with users. The evaluation will be conducted with common evaluation methods such as user tests, card sorting or heuristic evaluation. The objective of the evaluation is to test and compare the generated Information Architecture with a traditional one.

Although this project has just barely started, a prototype4 has already been tested with end-users in order to evaluate its functionality and usability. The goal of the tests conduced so far was to do a preliminary evaluation of the menu and facet components, to check if they are understood and they improve user performance when looking for a specific piece of information. The results so far show that LinkedData can improve the user experience, providing more ways to interact with data [START_REF] Gil | Improved Linked Data Interacting with the Web of Data through Information Architecture Components[END_REF].

Conclusions and Future Work

In this paper we have presented our vision of this doctoral thesis in the context of the Semantic Web and Information Architecture. We have started developing generic IA components that can be reused in websites with totally different domains as long as they are based on Semantic Web technologies.

The identified IA components are able to use the semantics captured by ontologies and semantic data, providing users different ways to access and interact with the data. Those components, which are automatically generated and maintained, facilitate publishing and browsing a dataset without requiring a priori knowledge of it or experience in Semantic Web tools.

The short-term future work focuses now on implementing the improvements detected during the user tests, basically those that affect the navigability between resources in the dataset. The main problem detected is that the user interaction is currently too constrained by how the underlying data is structured. The objective is to improve IA flexibility and obtain implicit properties and relations, for instance reverse properties, in order to provide users with alternative paths.

Then, we also plan to develop prototypes for the other identified IA components, test and evaluate them with users.

The work described in this paper has been partially supported by Spanish Ministry of Science and Innovation through the OMediaDis research project (TIN2008-06228).

This dissertation work is supervised by Roberto García

http://linkeddata.org/

http://rhizomik.net/linkedmdb/


Kellogg S Booth
email: ksbooth@cs.ubc.ca

Eleni Stroulia
email: stroulia@ualberta.ca

Supporting a Multidisciplinary Digital Media Research Community with GRAND Aspirations

Keywords:

ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

Grand challenges such as climate change, energy shortage, the threat of pandemics, and dealing with the accelerating pace of cultural shifts in society are being tackled through large-scale, multidisciplinary research teams. Digital media in its many forms is a tool for these organizations, but is itself a challenge to be tackled. The Graphics, Animation, and New Media network of centres of excellence (GRAND) has multiyear funding from the Canadian federal government for five research themes: (1) new media challenges & opportunities, (2) games & interactive simulation, (3) animation, graphics & imaging, (4) social, legal, economic & cultural perspectives, and (5) enabling technologies & methodologies. These span across disciplines, both public and private organizations, and provincial borders. Each theme has significant intersection with concerns familiar to the HCI community, and the management of the GRAND network faces problems well known in HCI for which are pursuing innovative solutions. We describe two aspects of our approach to these challenges.

Management structures to promote multidisciplinary research

Collaboration is "designed into" GRAND. Each of 34 projects has a project leader and co-leader from different organizations, often from different disciplines. Each of 64 principal network investigators (PNIs) is required to engage with multiple projects (three on average) and every project is expected to contribute to the goals of multiple themes. Projects are defined by a combination of top-down and bottom-up processes. Individual PNIs "invest" in projects by apportioning their funding amongst projects in which they engage. Theme leaders look for a balance across projects to advance the shared goals of the network. Funding to PNIs is based on contributions to those goals.

Information about the research is collected using a "report once, use often" strategy to minimize duplication of effort. Research activities, publications, prototypes and research artifacts are described by whoever first reports them and then re-used in subsequent reports. A wiki-like approach to maintaining information allows an initial reporter's information to be updated by others, and linked to all relevant projects, rather than requiring it be siloed into individual project reports. This raises mutual awareness and hopefully leads to serendipitous collaboration across projects. Following Pascal's dictum "The stream is always purer at its source [Les choses valent toujours mieux dans leur source]," the reporting hierarchy is flattened. Those doing the actual research (most often students and postdocs) provide the initial reports, with supervisors, then project leaders, and finally theme leaders synthesizing summaries in which "raw data" can always be accessed by drilling down.

Two special projects, Media Enabled Organizational Workflow (MEOW) and Network Assessment and Validity for Effective Leadership (NAVEL), will support and reflect on the activities of the GRAND community in a yin-and-yang symbiosis as GRAND evolves through its lifecycle. A set of tools built on the Mediawiki platform is a key component of this organizational management strategy.

The GRAND Forum: Scaffolding for collaboration

To streamline workflows and support communication and collaboration across the network, a web-based Forum is being developed that builds on the principles in the previous section. People in GRAND have roles that evolve over time. Explicit rolebased mechanisms manage individual's workflows and maintain a history of those roles (from graduate student to network investigator to industry sponsor). Access control policies associated with roles reflect a variety of concerns, including crossjurisdictional privacy legislation and IP ownership issues.

Activities such as entering information about a publication are simple single-step workflows. Others, such as reporting project milestones, involve the iterative collaborative editing of multiple pieces of information by multiple contributors, each with different reporting deadlines and degrees of editing authority. Those workflows are too complex to be specified simply at the user-interface level and are too human intensive to be "managed" by traditional workflow engines. We are developing a lightweight event-driven workflow specification and enactment web-service to address this requirement.

GRAND will be evaluated in part by whether its members increase interactions with each other over time. Tracking these relationships is at best tedious and at worst exhausting. We are developing a tagging approach -both interactive through the user interface and automatic through a text-analysis process -so that interactions with artifacts managed by the Forum will enable us to recognize communication channels between people and projects. Audit trails to substantiate information in the Forum and to enable effective use by all our members (subject to the access-control practices above) will be supported by full text and faceted search guided by the network's organizational structures, which are part of the scaffolding underlying the Forum.


Jesus Gimeno

Ricardo Olanda

Bibiana Martinez

Fernando M Sanchez
email: fernando.m.sanchez@uv.es

{jesus Gimeno

Multiuser augmented reality system for indoor exhibitions

Keywords: Augmented reality, interaction, augmented mirror

Over the last years, museums and galleries are looking for new ways to show exhibitions to visitors. For that purpose, new technologies like augmented reality are used. In this paper an augmented reality system for indoor exhibitions is presented. The system is formed by visualization screens that mix exhibition environment, visitors included, with multimedia and virtual 3D objects which visitors can manipulate naturally using a markers system. This system has been used in the exhibition "Valencia, tierra de comarcas: Diálogos con el patrimonio", which deals with a trip through the valencian cultural heritage.

Introduction and goals

Over the last years different technologies have provided museums and galleries visitors with a new form to see their stored knowledge. One of these technologies is augmented reality (AR). AR is an interaction paradigm that aims to combine computer-generated information with the real world [START_REF] Azuma | A Survey of Augmented Reality[END_REF].

Through AR within the indoor exhibition scope visitors can visualize, manipulate and browse exhibition information. Some usage examples of AR in museums and galleries are audio augmented guides [START_REF] Bederson | Audio augmented reality: a prototype automated tour guide[END_REF], head mounted displays-based applications [3][4], interactive museum guides over mobile devices [START_REF] Bruns | Enabling mobile phones to support largescale museum guidance[END_REF][6] [START_REF]Explorer: American Museum of Natural History[END_REF], screen visualizationbased systems [START_REF] Bimber | Spatial Augmented Reality[END_REF] and video projectors-based systems [START_REF] Mistry | WUW -Wear Ur World -A Wearable Gestural Interface Spatial Augmented Reality[END_REF].

The goal of the AR system presented in this paper is to provide an improved experience to the visitors by offering a better interaction with the exhibition contents. In order to do so, the system must immerse visitors into the augmented environment using an interface which allows a natural interaction with these contents. Moreover, the system has to provide to the visitors the educational information of the exhibition in a simple and enjoyable way.

System description

The AR system presented in this paper is composed of a Region of Valencia map, 7 pointers and several hosts which can work in an independent way or synchronized on the same exhibition environment. Each host is formed of a PC, two visualization screens and one Kinect camera [START_REF]Kinect Home Page[END_REF]. The map dimensions are 3x5 meters and visitors can walk on it. This map has a marker printed on it which is used to compute the spatial reference of the system. This map also contains 70 different hot points grouped by colors. Each color refers to a different subject of the Region of Valencia heritage and there is one pointer associated to each subject. Each pointer has a marker printed on it which is used to calculate its position on the map.

The system can be split into 4 subsystems. The communications subsystem communicates all hosts using a Client-Server model. It performs the synchronization between them over the same exhibition environment. The logic subsystem manages the system operation. It selects the subject associated to the active pointer in the system and identifies the hot point when the pointer is placed on it. The tracking subsystem obtains the position and orientation of the elements of the system: map, pointers and Kinect camera. The visualization subsystem shows augmented information over the real exhibition environment content. Figure 1 shows the different subsystems defined. In order to mix real exhibition content and augmented reality information, initially the Kinect camera captured information is painted. This image is a reflection of the real exhibition environment. Using the depth map information given by the Kinect camera, the values of the z-buffer [START_REF] Breen | Interactive Occlusion and Automatic Object Placement for Augmented Reality[END_REF] for each image pixel are calculated. In this way, the elements of the image, visitors included, can be placed correctly in the virtual scene. Finally, the virtual elements are painted taking into account the z-buffer information, performing a correct occlusion between real (visitors and exhibition room) and virtual (3D models, maps, etc.) worlds. This process can be observed in Figure 2.

Interaction process, augmented map

The visitors can walk on the large real map, as if they were traveling through the region of Valencia, using the different pointers to select the place they want to visit. When a visitor catches a pointer the system shows a multimedia resource of the subject selected on one screen. At the same time, on the other screen, an augmented visualization of a subject map replaces the real one. Thereafter, visitors can select a hot point of the selected subject on the map just "travelling" to the desired location and placing the pointer on it. Once the point is selected, a multimedia resource associated to it is showed on one screen, while on the other screen, a virtual 3D object is showed in the augmented visualization. In the same way, visitors can choose another hot point or change the subject selected by leaving the actual pointer and caching a new one. There are 3 different kinds of virtual 3D objects that can be displayed in the augmented visualization: 3D animated models which represent buildings or objects related to the hot point, virtual scenes created using images of real places and costumes to "dress up" the visitor.

Conclusions

The AR system presented in this paper has been used in the exhibition "Valencia, tierra de comarcas: Diálogos con el patrimonio". The system has worked properly and has been tested by over 1000 visitors. The visitor's opinions about the system were positive; they learned to use the system very fast, achieving a high level of satisfaction and entertainment.

According to the visitor's experiences, the goals have been met. The AR system was able to provide an improved experience to the visitors, supporting the learning process with the multimedia resources and virtual 3D elements associated to the hot points of the exhibition. Furthermore, the interface based on selection pointers and hot points located on the map was used by the visitors naturally.

Acknowledgements

The AR system development has been financed by the general foundation of the University of Valencia, with the collaboration of the "Vicerrectorado de Arte, Cultura y Patrimonio" and the Linguistic and Geography department.

Fig. 1 .

 1 Fig. 1. Augmented reality system components.

Fig. 2 .

 2 Fig. 2. Augmented reality scene composition using depth information.

Fig. 3 .

 3 Fig. 3. 7 Pointers and exhibition set (left); visitors using the system (right).


Stephann Makri
email: s.makri@ucl.ac.uk

Elaine G Toms
email: etoms@dal.ca

Lori Mccay-Peet

Ann Blandford
email: a.blandford@ucl.ac.uk

Encouraging Serendipity in Interactive Systems

We regularly make serendipitous discoveries in both online and offline contexts -from stumbling upon a useful website when searching for something completely different to meeting someone with mutual research or business interests in an unlikely place. However, most existing interactive systems do not provide a fertile environment for serendipity to occur. This workshop will identify key requirements and research challenges for designing and evaluating user-centred systems that aim to encourage serendipity.

Introduction and workshop objectives

While not usually life-changing like Fleming's discovery of Penicillin, we often make serendipitous discoveries that involve a mix of chance and insight and lead to a valuable outcome -, particularly when interacting with information and people. For example, consider finding a useful article for a paper you are currently writing while researching a different topic entirely, meeting someone with mutual business or research interests in an unlikely place such as at a conference on a different subject, or applying for a job position after being approached by a company that notices your enthusiastic tweets on Twitter.

Interactive systems cannot directly 'induce' serendipity. Indeed, it can be argued that even 'designing to encourage' it is an oxymoron; as soon as serendipity is 'engineered' into a system, discoveries might cease to be regarded as serendipitous even if they lead to a valuable outcome. This is because the system is likely to reduce the amount of chance and insight involved in the serendipitous discovery simply by helping to encourage it. So how can we harness the potential of this fleeting concept? How can we best design interactive systems that surprise and delight users without devaluing users' perceptions of the role of chance or insight? And how can we best evaluate the success of the systems we design if by designing to encourage serendipity, we might actually make the resultant discoveries appear to be less serendipitous than if they had been made without our assistance? With these tensions in mind, this workshop will identify key requirements and research challenges for designing and evaluating user-centred systems that aim to encourage serendipity. The workshop will be structured according to 3 themes: 1) understanding serendipity to inform design (i.e., what do we know and need to know about the conditions that stimulate serendipity?), 2) designing to encourage serendipity (i.e., what are the key requirements for designing interactive systems so that conditions are optimum for serendipity to occur?), and 3) evaluating the success of interactive systems aimed at encouraging serendipity (i.e., what approaches and criteria should we use to judge the success of the systems we design?).

Workshop structure and organisation

The workshop will begin with 1 minute introductions by each participant, focusing on serendipity-related interests. Next, multi-disciplinary groups of 3-4 chosen by the organisers based on attendees' research interests will sub-divide by the 3 workshop themes to discuss the current state-of-the-art for understanding serendipity, designing to encourage it and evaluating the success of interactive systems that aim to encourage it. Findings will be reported back to the workshop and the links across themes will be discussed as a whole group. After lunch, a group design activity will allow participants to consider how serendipity might be enabled by future technologies. Individuals will be asked to think of a novel interactive tool or system aimed at encouraging serendipity, then pair up with someone from a different institution with a similar/complementary idea. The process will be repeated to form groups of 4 and these groups asked to devise a scenario of how their tool/system might be used and reflect on the key requirements and research challenges highlighted by their scenario for understanding serendipity and designing and evaluating systems aimed at encouraging it. Each group will present their scenario and a summary of the requirements and research challenges identified. This will be followed by a plenary discussion on how the identified requirements and challenges might be addressed through future research efforts. Finally, there will be an optional group dinner.

Target audience and expected workshop outcomes

To encourage a range of perspectives during discussion, and fitting with this year's conference theme, this workshop aims to 'build bridges' by bringing together up to 20 participants from a mix of HCI and related disciplines (e.g. Design, Psychology, Information Retrieval, Information Science and Computer Science) who share an interest in the user-focused design and evaluation of interactive systems that aim to encourage serendipity. We expect most participants to be researchers or PhD students as well as practitioners who are currently involved in developing interactive systems.

We have created a workshop website to facilitate discussion, knowledge-sharing and post-workshop collaboration (http://sites.google.com/site/serendipityworkshop). The current approaches and research challenges identified for each workshop theme and future research directions will be summarised on the site and will form the basis of an article to be submitted to ACM Communications and one aimed at communicating our findings to practitioners in a magazine such as Interactions.

Acknowledgements. This work is partly supported by EPSRC Project EP/H042741/1 to Blandford, and NCE GRAND and a SSHRC grant to Toms.


Stefan Sauer
email: sauer@s-lab.upb.de

Kai Breiner
email: breiner@cs.uni-kl.de

Heinrich Hussmann
email: heinrich.hussmann@ifi.lmu.de

Gerrit Meixner
email: gerrit.meixner@dfki.de

Andreas Pleuss
email: andreas.pleuss@lero.ie

Jan Van Den Bergh
email: jan.vandenbergh@uhasselt.be

Combining Design and Engineering of Interactive Systems through Models and Tools (ComDeisMoto)

Keywords: user-interface engineering, interaction design, model-driven development, user-centered design, models

Development of interactive systems and their user interfaces combines engineering and design, formal and informal development methods from different domains. Diverse models and tools can be used to support the developers' work. In model-driven development, software systems are specified systematically using dedicated models for different aspects of the system. Yet, appropriate design of user interfaces is as important as functional correctness. This workshop provides a forum of multi-disciplinary discussion on how to integrate model-driven development with the often more informal methodologies used in user-centered design and engineering. Starting point of the discussion are the tools, models, methods and experiences of the workshop participants.

Model-Driven Development of Interactive Systems

Model-Driven Development (MDD) has become an important paradigm in software development. In MDD, models are the primary artifacts in the development process. Models are often visual models, like UML models, but can also be represented in textual formats like XML. Each model is denoted by a modeling language that can be tailored to the according stakeholders while still remaining machine applicable.

Analogous to traditional software development, MDD processes leverage models on different levels of abstraction. But unlike traditional software development, the transition between the levels can be described in a formal way and enable (semi-) automatic transformations between the levels, even finally into implementation source code. Having models as development artifacts also enables the application of model checking methods for verification, early testing or tool support.

MDD provides a large number of powerful concepts and tools to deal with models, meta-models, and model transformations. Together, they provide support for systematic and efficient software development.

Model-driven development of interactive systems (MDDIS) and, in particular, their user interfaces (UI) applies the principles of MDD to the target domain of interactive systems and UIs. While traditional model-based user interface development approaches have not spread widely into practice in the past, requirements of new interaction devices, e.g. demanding for device independence, make model-driven approaches more and more important. One major advantage of MDD is that there are different models for particular purposes. One well-known use case is to separate the content (what is displayed) from the design (how it is displayed) into distinct models.

This workshop follows the series of workshops on model-driven development of advanced user interfaces (MDDAUI), held in 2005-2010. In the five editions of that workshop series we have seen a lot of models, transformations and tools for modeldriven user interface development. These approaches also tackled advanced UI features like multi-platform development and plasticity, context-sensitiveness, multimedia, 3D and augmented reality, ambient production environments, wearable sensors, interactive TV, and many others.

Design and Engineering: Enhancing the User Experience

The previous workshop editions have shown that concepts for model-driven user interface development are already becoming mature. However, the quality of the resulting UIs, in terms of the user experience, has always been one of the most important challenges. In some cases, the UIs generated from the models can even improve the usability as they are for instance very consistent. However, it comes to a drawback if some parts of the UI require individual design e.g. because of its complexity or to increase the likeability of the product.

For these reasons, an optimal development method should support both: systematic MDDIS and incorporation of individual design knowledge, the latter usually resulting from manual, informal methods in user-centered design.

Workshop Goals

This workshop focuses on challenges, opportunities, practical problems, and proposed solutions to integrate MDDIS and informal design methods and tools. It aims at fostering interdisciplinary discussions between the respective expert groups and viewpoints. Workshop participants investigate how models, tools and current or future MDD techniques can be combined with design expertise in a way that improves the development process for interactive systems, better supports the work of UI creators and eventually benefits the user experience of end users. Our objective is improving the tools for software engineers and UI developers, being the creators and users of models, e.g. by integrating design measures in engineering models, providing modeling tools for designers or novel methods for MDD, etc.


Llúcia Masip

Marta Oliva
email: oliva@diei.udl.cat

Toni Granollers
email: tonig@diei.udl.cat

OPEN-HEREDEUX: OPEN HEuristic REsource for Designing and Evaluating User eXperience

Keywords: user experience, evaluation resources, heuristic evaluation

The need of enhancing design and evaluation of user experience exists. We propose a resource which helps to semi automate the design and evaluation of user experience.

User Experience

The concept of User eXperience (UX) includes more facets than traditional ones related to usability. According to Peter Morville [1], UX includes useful, usable, valuable, desirable, findable, credible and accessible. Moreover, other authors also consider aspects such as communicability, cross-culture, emotions or playability.

Facets help us to improve the quality of use in interactive systems and, consequently, to increase UX. Despite the new tendency in UX, currently there is no specific technique to evaluate UX when users interact with an Interactive System (IS) [START_REF] Vermeeren | User Experience Evaluation Methods: Current State and Development Needs[END_REF]. Certainly, UX experts can use usability evaluation methods for evaluating UX, because the "oldest" and the most traditional facet used when evaluating aspects related to the quality of use is usability. Nevertheless, a consensus about what is the best methodology to evaluate UX still does not exist [START_REF] Vermeeren | User Experience Evaluation Methods: Current State and Development Needs[END_REF].

The project which I am involved in with my PhD is contextualized in UX evaluation but focusing our efforts on exploiting the capabilities of one of the methods used most: the heuristic evaluation (HE). HE, as it is known in HCI field, was spread by Nielsen and Molich [START_REF] Nielsen | Heuristic evaluation of user interfaces[END_REF] but HE had been discreetly created by Ravden and Johnson in [START_REF] Johnson | Towards a practical method for user interface evaluation[END_REF]. It is one of the most challenged and successful methods for evaluating the usability of interactive systems. Nevertheless, HE presents barriers that induce a slower and more expensive evaluation process that could lessen all its advantages. The first deficiency is that the whole evaluation process is based on considered heuristics. A review of this set, to adapt it to specific features of interactive systems is always essential despite the fact that experts have done many efforts to provide a whole set of heuristics and apply them to different interactive systems. The second deficiency is in the evaluation result. Usually, the method provides qualitative results. And more often than not, qualitative results are not enough if these results do not allow us to take decisions in an objective way like it happens with quantitative results. In this context, the following sections explain our ideas to go a step beyond to provide solutions for the mentioned above problems.

OPEN-HEREDEUX

OPEN-HEREDEUX is the short name which we use to refer to the project called: "OPEN HEuristic Resource for Designing and Evaluating User eXperience in interactive systems". It will enable UX experts to design and evaluate UX in a semi automates way. Its four components are detailed below.

Open repository of heuristics

The main goal of this component is to manage information. We should provide a repository with all the information needed to achieve a complete and minimum set of heuristics and to consider all aspects of UX either in its design phase or evaluation process for a specific IS.

Therefore, the repository will have all information such as a whole IS classification [START_REF] Masip | Classification of interactive systems components enables planning heuristic evaluation easier[END_REF], essential facets to evaluate UX in any IS and a complete set of heuristics related to all the facets mentioned previously.

Once we have all this information, next step will be data modeling; we will model information through ontologies. Finally, all information will be stored with the most convenient technique to be able to extend, modify or delete this information later. All this information will be used as input for the next component, the heuristics adviser.

Adviser of heuristics

The main goal of the heuristics adviser component is to propose the most convenient list of heuristics to be used (for the specific system to be analyzed), such as recommendation principles in a design phase or such as evaluation principles in a UX evaluation based on heuristics.

The adviser considers for its suggestion different factors according to the type of IS and other factors such as economics, etc. About the type of IS the adviser should at least regard the facets considered in this IS and the minimum but complete set of heuristics of each facet according to the user profile that needs these heuristics (designer or evaluator). In reference to economical factors, the heuristics adviser should consider the time that designers or evaluators have to take into account for the set of heuristics and the money invested in the project. These factors should determine the minimum number of heuristics that the adviser should suggest. This component has an important advantage when choosing the best heuristics for a specific IS: turning a manual process and process based on UX expert experience to semi automate process where UX experts will only review the set of heuristics suggested.

Finally, heuristic suggestions can be used either as a list of recommendations to design a specific IS or as an input of a scoring interface.

Scorer of heuristics

If we want to use the adviser's set of heuristics to evaluate UX, we can carry out the evaluation using this component. It helps UX evaluators in their scoring of heuristics. It should have a control of user profiles to identify if the user is connected to the system as an evaluation administrator or as an evaluator; the interface provides users with two parts according to each user profile. The first part is the administration part where administrator should review the heuristics suggested by the adviser, and should choose the evaluators and the severity factors. The second part is the evaluation part where evaluators should score every heuristic. In addition, this component stores all the information to make the extraction of qualitative and quantitative results easier.

Results analyzer

The last component waits for the extraction of quantitative and qualitative results. In reference to qualitative results we will try to create a list of improvements according to evaluators' observations and heuristics scored incorrectly. They are ones which designers should apply to interactive systems. Apart from qualitative results, we want to obtain quantitative ones because these will try to show the degree of UX that an IS has. If quantitative results are achieved, UX experts will have a standard method or a possible certification to compare evaluations and see which IS provides users with the best experience. Quantitative results will get an objective measure that we cannot achieve with the subjectivity of qualitative results.

Research already conducted

In reference to the evaluation planning, all these ideas started when we had to carry out an evaluation of physical devices called CIPs (Citizen Information Point) [START_REF] Oliva | Evaluación de usabilidad y accesibilidad de un conjunto de dispositivos interactivos denominados Puntos de Información Ciudadana[END_REF]. We realised that we could not use some well-known heuristics such as Nielsen's. These were GUI-focused and, they did not cover our evaluation goals and all the features of CIPs. We started researching as much as possible all general usability heuristics defined since 1986 and we detected 16 repeated categories. They are applicable in simple websites or desktop applications [START_REF] Masip | Hacia la semiautomatización de la evaluación heurística: Primer paso, categorización de heurísticas, Interacción 2010[END_REF].

Apart from this review, we achieved a classification of IS components that permitted us to know what parts of the IS should be assessed and to choose the best heuristics for each part [START_REF] Masip | Classification of interactive systems components enables planning heuristic evaluation easier[END_REF]. Then, we validated these 16 categories making a comparison between two sets of heuristics to detect which set can find more usability problems and to detect improvements in their definition [START_REF] Masip | A Heuristic Evaluation Experiment To Validate The New Set Of Usability Heuristics[END_REF]. And in addition these heuristics might work in semantic applications, now we are working in it. In reference to the results, we have already made an effort to achieve a mathematical formula in usability HE [9], we do not rule out our option but we know that we have to do more research on it.

Currently, we are working on different areas of this project. The first one is modeling dates to be able to achieve the first version of the adviser. Second, we are working on the design of the second component of our resource: the heuristics scorer component. In addition, while all this work is being done, we are also doing research on all the information needed for our open repository although we know this information about heuristics, facets and new interactive systems can increase (for this reason our repository is an open repository).

In the future we will primarily on quantitative results to achieve a statistical or mathematical formula towards UX standardization.

Acknowledgements:

The work has been partially supported by Spanish Ministry of Science and Innovation through the Open Platform for Multichannel Content Distribution Management research project (TIN2008-06228) and it has been partially supported by Universitat de Lleida for pre-doctoral fellowship to Llúcia Masip.


Daniel Gonçalves
email: daniel.goncalves@inesc-id.pt

Luis Carriço

Markel Vigo
email: markel.vigo@manchester.ac.uk

Mobile Accessibility Workshop

Keywords: Mobile Accessibility, mobile computing, accessibility, workshop

ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

Topic and Objectives

In recent years, we have witnessed an increasing importance of mobile devices. They pervade our daily lives, not only just in the form of feature phones, but also as smartphones and tablets. Tablets in particular have been the object of much attention, lately. They are set to be one of the fastest growing mobile device markets. What is more, they have the computing power of small computers. This is also true for the most advanced smartphones and mobile operating systems. We are, thus, in the cusp of a fundamental change in how we relate to information and others, accessible at all times and places with the help of mobile devices.

Alas, this change might be barred to a large number of people, suffering from a wide range of disabilities. Mobile devices are increasingly visual, making them hard to use by the blind or other vision-impaired people. Keyboards are steadily being replaced by touchscreens, without tactile feedback, introducing additional barriers. Tetraplegic users have limited mobility of their limbs and hardly are able to pick up the devices or use their fingers for precise pointing. Additionally, mobile devices are being used as mediators to reach distal interfaces (e.g. interactive TV, information kiosks, etc.) providing people with disabilities with the means to potentially overcome physical barriers and freely interact with the environment.

Moreover, the mobile aspect often creates situations where those interaction modes are cumbersome or socially unacceptable, even for non-impaired people. Riding a bicycle on a mountain trail and looking at the maps at the same time is difficult and dangerous. Timely responding to urgent and confidential solicitations on a public site may be distressing or embarrassing. These are considered situational disabilities that often introduce similar problems to the use of mobile apparatus. Overall, the list of problems is immense.

Fortunately, there is a nascent area of research, Mobile Accessibility, where researchers are focusing on solving accessibility problems in mobile devices and settings. Bringing together Mobile Computing and Accessibility, it is the source of synergistic works that have the potential of deeply transforming how we look at mobile devices, and to shape the ongoing mobile revolution. Work in this area ranges from new text introduction techniques to multimodal interaction solutions, mobile assistive technology, prototyping tools, navigation tools, theoretical models, etc. A wide range of users and situations is also considered (blind, tetraplegic, elderly, deaf, etc.). As a result, solutions provided to people with disabilities could be applied to the aforementioned situationally impaired users.

Papers on Mobile Accessibility have become an increasing presence in conferences such as CHI, Assets, W4A and MobileHCI, proof of a growing and active community. However, there has been a lack of a single well defined venue for the topmost researchers in the area to meet and exchange ideas and results. We propose, in this first Mobile Accessibility Workshop, to provide such a venue. It is our objective to bring together researcher and practitioners with clear advantages in terms of critical mass, synergies, collaborations and networking, and unmistakable benefits for the area.

Participants

Organizers: The workshop will be organized by Prof. Daniel Gonçalves, Prof. Luís Carriço and Markel Vigo, all of them researchers in mobile accessibility, with several papers published in the area.

Intended Audience: Researchers and practitioners of Mobile Accessibility, both from academia and industry, in any of its facets (as described in the introduction).

Expected participants: we expect to attract 12-18 participants.

Organization

Duration: the workshop will last an entire day Format: the workshop will consist, mainly, of peer-reviewed paper presentations by its participants. We'll solicit submissions using the Interact short paper template.

Extended versions of the best papers will be chosen for submission to a Special Issue of the Universal Access in the Information Society Journal