Ellya Zulaikha
email: ellya.zulaikha@student.qut.edu.au

Margot Brereton
email: m.brereton@qut.edu.au

Communication Choices to Engage Participation of Rural Indonesian Craftspeople in Development Projects

Keywords: Communication Mode, Rural Craftspeople, Participatory Design, Participatory Development

In participatory design projects, maintaining effective communication between facilitator and participant is essential. This paper describes the consideration given to the choice of communication modes to engage participation of rural Indonesian craftspeople over the course of a significant 3 year project that aims to grow their self-determination, design and business skill. We demonstrate the variety and subtlety of oral and written forms of communication used by the facilitator during the project. The culture, the communication skill and the influence of tacit knowledge affect the effectiveness of some modes of communication over the others, as well as the available infrastructure. Considerations are specific to the case of rural Indonesian craftspeople, but general lessons can be drawn.

Introduction

In theory the use of Information and Communication Technology (ICT) should assist rural business to access and compete in global markets. However, scholars widely acknowledge that ICT application in rural business is problematic [START_REF] Galloway | Can broadband access rescue the rural economy?[END_REF][START_REF] Kshetri | Barriers to e-commerce and competitive business models in developing countries:A case study[END_REF]. There is a lag in uptake of ICTs in rural areas and review of a wide array of disparate initiatives found that interventions are best undertaken through multi-channel approaches and internediaries [START_REF] Cecchini | Can information and communications technology applications contribute to poverty reduction? Lessons from rural India[END_REF][START_REF] Galloway | The use of ICT in rural firms: a policy-orientated literature review[END_REF]. However, imposing the use of ICT may not always meet the needs of rural people nor might ICTs suit the local context. Instead of beginning with the assumption that ICT in some form is needed to enhance the livelihoods of rural people, this project begins by examining how rural craftspeople communicate and how they engage to participate in projects to develop their livelihoods Such understandings would in any case need to underpin efforts to adopt ICTs. This paper describes a case study of a participatory approach to engage participation of rural craftspeople in a development project, focusing upon the communication modes used by the intermediary.

Rural craftspeople producing traditional handmade products currently struggle to stay in business. The common problems of rural craftspeople are lack of innovation, management skill and capital. One rural craft industry which currently faces these difficulties is the Jombang glass bead craft industry in Indonesia. There used to be hundreds of craftspeople running glass bead businesses, but in the last decade the number has decreased to just over 20, and it is still decreasing.

Advisory programs have been provided to address these problems such as design and management training, and facilitation to sell craft products. Such advisory programmes are common for rural craft industries in Indonesia. While these programs offer value and give new insights to craftspeople, they do not fully engage the imagination, capacity and innovation of craftspeople. As top-down policy initiatives, these programs overlook the unique potential of the participants as well as the local context. Additionally, the complexity of the rural craft community with its inter-related aspects of communal life was ignored.

This action research project has undertaken participatory design with rural craftspeople in order to explore how they can develop their craft practice and livelihoods. Participatory design involves them fully in decision making processes, is grounded in their local context, respects their skills, allows them to exercise self-determination, and respects the unique potential of each participant.

Communication is one key to success of a participatory project. Therefore, it is necessary to examine how communication occurs and effective modes of communication. This knowledge can inform application of ICTs for rural craftspeople.

2

The Participatory Approach

Participatory methods have been used in many fields. The fundamental tenet of participatory methods is empowering participants to have a better say in determining their future. Good communication enables better quality participation. However, engaging participants can be challenging. As stated by Bebbington et.al, rural people will not share their problems nor their ideas in situations that are not conducive [START_REF] Bebbington | Village politics, culture and community-driven development: insights from Indonesia[END_REF]. Knowledge of cultural sensitivity and the local political situation is essential to creating conducive situation. Interpersonal and political skills of facilitators are also needed to create conducive situations [START_REF] Park | What is Participatory research? A Theoretical and Methodological Perspective[END_REF].

Communication as an essential aspect of participatory project

The most crucial phase of participatory projects is "entry to the field" and building an initial relationship with participants [START_REF] Dearden | Participatory IT Design and Participatory Development : A comparative review[END_REF][START_REF] Park | What is Participatory research? A Theoretical and Methodological Perspective[END_REF]. Nevertheless the success of this phase depends upon the communication skill of the facilitator.

In the literature that examines the effectiveness of different communication channels, Maltz argued that the chosen communication medium will affect the quality of information, in terms of its richness, spontaneity and speed [START_REF] Maltz | Is all communication created equal?: An investigation into the effects of communication mode on perceived information quality[END_REF]. Hollingshead argued that communication medium is less influential on the quality of group decision making [START_REF] Hollingshead | Information suppression and status persistence in group decision making the effects of communication media[END_REF], which is influenced more by the equality of social status among members in a group. However, Hollingshead did not consider the role of facilitators. In participatory projects involving internediaries, the quality of communication and resulting decisions also depends on the facilitator's skill to mediate the discussion in order to avoid domination etc.

2.2

The challenge of initiating the participatory project Different societies hold different understandings of participation based on their local value systems [START_REF] Winschiers-Theophilus | Being participated: a community approach[END_REF]. Facilitators should understand the values in the community [START_REF] Winschiers-Theophilus | Being participated: a community approach[END_REF] and how to deal with them before initiating a participatory project. Western techniques for engaging participation are not necessarily suitable for eastern cultures [START_REF] Winschiers-Theophilus | Being participated: a community approach[END_REF].

Negative consequences of relationships caused by misunderstandings can occur.

There has been little research exploring communication for engaging participation from the context of eastern culture.

Overview of the three year participatory project

The communication strategies described below have been developed as part of a three year project. The first phase in year 1 involved ethnographic study, interviewing craftspeople about their livelihoods, artistic and business perspective and attitudes towards sharing. The second phase in year 2 involved a series of collaborative design workshops between industrial design students from the local urban university and the rural craftspeople in which they worked together to develop new designs that both reflected their own values and local culture but that also tapped into the design expertise of formally trained students. This series of workshops led them to collaboratively create new designs that were sold in government craft outlets, and served to increase their design confidence. The third phase in year 3 involved the craftspeople developing their own project. They decided to increase local awareness of their craft by taking a road-show to local schools and engaging school children in making glass products with them. They were very proud to demonstrate and teach their skills and to raise awareness of the local craft. This paper discusses communications in year 3.

Method

The researcher acted as facilitator, along with 4 young design students from local institutions and 2 professional designers in the participatory project. All have a similar cultural background with the rural community, enabling them to understand sensitive issues within the culture. Additionally, the first author has 10 years experience of working with rural craftspeople, which is advantageous for approaching participants.

However, a similar cultural background is not enough to build trust and a close relationship for further collaborative projects. Strong interpersonal skills gained from experience and maturity are more influential in fostering the process. For example, when the conversation with craftspeople unintentionally moves to a sensitive issue within the community, the facilitator must give an appropriate response to maintain a neutral position as well as to keep a positive outlook.

Facilitators were also aware of social hierarchy as a hallmark of Javanese Society [START_REF] Beard | Individual determinants of participation in community development in Indonesia[END_REF]. Therefore, the facilitator identified and approached the community leaders, whose recommendation usually influenced the community decision.

The community meeting to decide a project

Once the researcher gained the trust of the community, she organized a community meeting on a weekly basis for two months in 2012. Each meeting was attended by six to twenty craftspeople. Most of participants had graduated from high school.

The first meeting began with icebreaking in order to create an informal and joyful situation, using a game that involved pairing Indonesian celebrities, and a discussion of punishments for participants who made unconstructive comments, yielding laughter and a relaxed atmosphere. A modified 'string game'1 was employed to make sure that everyone had a turn to speak and share their opinion. These initial activities were crucial to get craftspeople comfortable in participating. Then, through the intensive discussion in the community meetings, the craftspeople decided to organize events to promote the industry to local buyers through a glass-bead-making workshop. Local high schools surrounding the industry were selected as targets for pilot projects.

The glass bead making workshops for high school students aimed to provide insight into glass beads as a part of Indonesian history and culture, as well as allowing the students to experience making glass beads with assistance from craftspeople. Each workshop lasted 3 hours.

By the end of the events, craftspeople gained a positive response from schools. In total, there were 160 participants in the workshops. Two schools asked for further workshops and enthusiastically allocated the project as an alternate extra-curricular activity for students. Meanwhile, some students expressed their desire to implement their design and meet craftspeople in their place. Overall, the participants showed that they respected and were interested in the local products.

There are social and economic benefits for craftspeople through these workshops. The social benefits were indicated by the new network built with local high schools while the economic benefit was gained by the product sales and payment as a tutor for the workshop. The glass-bead-making workshop has a strong potency to enhance the craft industry because; firstly it spread the information about the industry to local buyers, secondly it enables future networking between the craft industry and schools. It also developed confidence in the craftspeople to engage externally in this way.

The Choice of Communication Mode

The researcher used both oral and written communication modes during the project. Oral communication was delivered by face-to-face contacts and phone calls while the written communication was mainly by texting (Short Message Service / SMS). Researchers also used printed material (a letter) and email, but did so rarely. Communication was not only about the project, but also to express appreciation and greetings related to special community occasions such as the coming of Ramadan. Table 1. shows that the oral mode of communication was more commonly used than written mode. Collective face-to-face interaction was the oral mode most frequently used during the project, followed by individual face-to-face, then by phone. Phone calls were used to contact community leaders; first to introduce the researcher prior to meeting, second to make an appointment, and also when certain issues needed to be discussed with certain people. Meanwhile, SMS was the only frequent mode used for written communication. Most SMSs were sent collectively, ie from the facilitator to multiple recipients. However, it was one way rather than reciprocal communication. Mail and email were the least used modes. The researcher had tried to spread Nevertheless, the use of local language must be done carefully. Javanese speech consists of some levels that reflect politeness and honorific expression [START_REF] Galloway | Can broadband access rescue the rural economy?[END_REF]. Inappropriate use is impolite and reflects cultural insensitivity. Accordingly, the facilitator used a high level of Javanese speech (Kromo) when speaking to an older or respected person; and medium level (Ngoko) to a person of similar age and social status.

The other important issues of communicating with craftspeople orally are the intonation and the type of sentence. The facilitator kept speaking in an informal intonation to maintain friendliness, expressing ideas as questions to solicit feedback. This gave craftspeople a chance to interact, engage their responses and avoid passivity. Otherwise the facilitator would miss key information about their ideas or feelings.

The use of Indonesian language in written mode was to ensure that the message was understandable. Nevertheless, it created a formal impression which means distance. Therefore, the facilitator must maintain friendliness feeling and politeness when sending SMS, by using a structure of: "greeting (thanks to God) + main content + thank you". Craftspeople did not necessarily reply to messages. Replies usually comprised only one or two words, such as "Yes mam". Nevertheless, no response did not mean they were not interested in the issue.

Discussion

The most effective mode of communication during the project was face-to-face interaction and SMS. Face-to-face meeting conveyed tacit knowledge by the style of speech, dress, or even means of transportation used; in addition to the verbal message. Tacit knowledge builds trust and rapport which are essential to effective networking practice [START_REF] Swan | Knowledge management and innovation: networks and networking[END_REF]. In addition, collective face-to-face interaction enabled immediate response from community leaders and other members. Rural communities have a strong cohesive culture in which their decision will be greatly influenced by a respected person or persons. Collective face-to-face meeting accelerated effective engagement. The low usage of email or mail was apparently caused by the limited written communication skill of craftspeople. Email was also less popular as the infrastructure is insufficient to support a reliable communication. creating more obstacles to use than SMS or phone.

Conclusion

Communication choices to engage participation in this context considered several aspects: the communal culture, the limited written skill and the influence of tacit knowledge. The influence of community leaders, as is characteristic in rural communal culture, affected the communication effectiveness as well as engaging participation. The limited written skill of participants meant that oral modes were used more than written mode, especially when immediate responses were needed. The use of language and mode of communication must be carefully selected, as it taps into tacit knowledge which is essential in building trust and rapport while communicating with rural people.

Fig. 1 .

 1 Fig. 1. Napkin Rings designed together by craftspeople and designers

Fig. 2 .

 2 Fig. 2. The glass-bead-making workshop: high school students learnt to make a glass bead, assisted by craftspeople.

Each participant chooses one of provided strings, then he must talk as they slowly wind the piece of string around their index finger. The person must keep talking until reaching the end of the string. (source: http://www.icebreakers.ws/small-group/string-game.html)

Acknowledgements

I would like to first appreciate the work of Jombang glass bead craftspeople during the project. This work is supported by a scholarship from the DIKTI on behalf of the Ministry of National Education, Republic of Indonesia.

information through this mode, but there was insufficient response, so she used oral mode and SMS instead.

5

The Use of Language in Each Communication Mode

We combined Indonesian and Javanese language for communication during the project. The bilingual use of language is common in current Javanese society. The Javanese language provides a sense of closeness and facilitates building relationships with participants. The local language is commonly used in oral communication, but is rarely used in written communication. On the other hand, Indonesian as the language of formal instruction in school is used for reading and writing purposes, as well as in formal situations. Thus, we used the Javanese for oral mode, but Indonesian language for written mode. In collective meetings, we used both Javanese and Indonesian.


Weidong Huang

Leila Alem
email: leila.alem@csiro.au

Franco Tecchia
email: f.tecchia@sssup.it

HandsIn3D: supporting remote guidance with immersive virtual environments

Keywords: remote collaboration; co-presence, mixed reality, hand gesture, shared visual space

A collaboration scenario involving a remote helper guiding in real time a local worker in performing a task on physical objects is common in a wide range of industries including health, mining and manufacturing. An established ICT approach to supporting this type of collaboration is to provide a shared visual space and some form of remote gesture. The shared space and remote gesture are generally presented in a 2D video form. Recent research in tele-presence has indicated that technologies that support co-presence and immersion not only improve the process of collaboration but also improve spatial awareness of the remote participant. We therefore propose a novel approach to developing a 3D system based on a 3D shared space and 3D hand gestures. A proof of concept system for remote guidance called HandsIn3D has been developed. This system uses a head tracked stereoscopic HMD that allows the helper to be immersed in the virtual 3D space of the worker's workspace. The system captures in 3D the hands of the helper and fuses the hands into the shared workspace. This paper introduces HandsIn3D and presents a user study to demonstrate the feasibility of our approach.

Introduction

It is quite common nowadays for two or more geographically distributed collaborators to work together in order to perform actions on physical objects in the real world. For example, one remote expert might be assisting an onsite maintenance operator in repairing a piece of equipment. Such collaboration scenarios are highly asymmetrical: the onsite operator is co-located with the machine being manipulated or fixed but does not have the required expertise to do the job, while the remote expert does not have physical access to the machine but knows how to trouble shoot and fix it. This type of collaboration scenarios is common in many domains such as manufacturing, education, tele-health and mining. When co-located, collaborators share common ground, thus being able to constantly use hands gestures to clarify and ground their messages while communicating with each other verbally. However, when collaborators are geographically distributed, such common ground no longer exists, resulting in them no being able to communicate the same way as they do when co-located. Prior research has shown that providing shared visual spaces and supporting remote gesture can help to build common ground [START_REF] Fussell | Gestures over video streams to support remote collaboration on physical tasks[END_REF][START_REF] Gergle | Using Visual Information for Grounding and Awareness in Collaborative Tasks[END_REF]. A shared visual space is one where collaborators can see the same objects at roughly the same time. As a result, a number of remote guiding systems have been reported in the literature to achieve these two goals. While how remote gesture is supported may differ from system to system (e.g., [START_REF] Alem | HandsOnVideo: Towards a gesture based mobile AR system for remote collaboration[END_REF][START_REF] Gurevich | TeleAdvisor: a versatile augmented reality tool for remote assistance[END_REF]), the shared visual space is generally provided in the 2D format of either video feeds or projection on surfaces.

A recent study on a remote guidance system by Huang and Alem [START_REF] Huang | Gesturing in the Air: Supporting Full Mobility in Remote Collaboration on Physical Tasks[END_REF] indicated that with 2D shared spaces, helpers had difficulties in perceiving spatial relation of objects. Helpers also had a relatively lower sense of co-presence [START_REF] Huang | Supporting Hand Gestures in Mobile Remote Collaboration: A Usability Evaluation[END_REF]. Spatial understanding is critical for helpers to make right judgements on objects and guide workers accordingly, while co-presence has been shown to be associated with user experience and task performance [START_REF] Kraut | The Use of Visual Information in Shared Visual Spaces: Informing the Development of Virtual Co-Presence[END_REF]. Therefore, these are two important factors and should be addressed properly.

Research has shown that immersive virtual environments (IVEs) help improve spatial understanding [START_REF] Schuchardt | The benefits of immersion for spatial understanding of complex underground cave systems[END_REF]. Further, IVEs also bring other benefits [START_REF] Mortensen | Collaboration in tele-immersive environments[END_REF], such as higher sense of co-presence, improved spatial awareness, more accurate cognitive transfer between simulation and reality and better task performance. Although they have been shown useful in supporting general tele-collaboration in which all collaborators work within the same virtual environment, we wonder if IVEs still help in the context of remote guidance.

We therefore propose a new approach that provides 3D shared visual spaces. A prototype system called HandsIn3D has been developed for the purpose of the proof of concept (see [START_REF] Tecchia | 3D helping hands: a gesture based MR system for remote collaboration[END_REF] for more details). This system uses a head tracked stereoscopic HMD that allows the helper to be immersed and perform guidance in the virtual 3D space of the worker's workspace. In the remainder of this paper, we introduce HandsIn3D and present a user study of it.

HandsIn3D

HandsIn3D is currently running on a single PC. It has two logical sections: the worker space and the helper space (see Figure 1). The worker performs a physical task at the worker space, while the helper provides guidance to the worker at the helper space. The left image shows the layout of the worker space. A user sits at the desk performing a task on physical objects (for example, assembly of toy blocks). A 3D camera is mounted overhead to capture the workspace in front of the user including the hands of the user and objects. A LCD non-stereoscopic monitor is placed on the desk to display the 3D view of the workspace augmented by guiding information. The right image of Figure 1 shows the layout of the helper space. In this space, there is a 3D camera that captures the hands of the helper. The helper wears a stereoscopic HMD and sits in front of an optical head tracker. The HMD allows a realistic virtual immersion in the 3D space captured by the camera placed in the worker space, while the tracker tracks the HMD position and orientation. The shared virtual interaction space is shown in the LCD monitor. The 3D meshes captured by two cameras are co-located and fused together. Four hands can be spotted in the virtual scene: 2 from the worker and 2 from the helper [START_REF] Tecchia | 3D helping hands: a gesture based MR system for remote collaboration[END_REF].

The system functions as follows. On the worker side, the worker talks to the helper, looks at the visual aids on the screen, picks up and performs actions on the objects. On the helper side, the helper wears the HMD, looks into the virtual space (and looks around the space if necessary), talks to the worker and guides him by performing hand gesture such as pointing to an object and forming a shape with two hands. During the process of interaction, the camera on the worker side captures the workspace in front of the worker, while the camera on the helper side captures the hands of the helper. The acquired 3D scene data from both sides are fused in real time to form a single common workspace which we call shared virtual interaction space. This space is displayed in HMD. The image in Figure 2 is provided to help understand what is presented to the helper during the task execution: by fusing together the 3D meshes acquired by the two cameras, an augmented view of the workspace where the hands of the helper are co-located in the worker space is synthetically created, as shown in the LCD monitor. On the other hand, being presented with this augmented view, the worker can easily mimic the movements of the helper hands and perform the Lego assembly task accordingly.

The main features of the system therefore include the following:  Users can speak to each other.  The helper can see the workspace of the worker via the shared virtual interaction space.  The helper can perform hand gestures.  The worker can see the hand gestures of the helper on the screen.  The two hands of the worker are freed for manipulation of physical objects. In addition, the shared virtual interaction space also implements features to improve the sense of 3D immersion for the helper. These features include 1) the objects and helper hands cast shadows in the space; 2) the HMD is tracked which allows the helper to see the space from different angles.

A User Study

The user study was conducted to evaluate our 3D gesture based interaction paradigm. We were particularly interested in how helpers felt about the 3D user interface.

Method

Fourteen participants who had no prior knowledge of the system were recruited. Upon their agreement to participate, they were randomly grouped as pairs to perform a collaborative task. In this study, we used the assembly of Lego toy blocks as our experimental task, which is considered as representative of real world physical tasks and has been used for the similar studies. During the task, the worker was asked to assemble the Lego toys into a reasonably complex model under the instruction of the helper. The helper was instructed that he could provide verbal and gestural instructions to the worker at any time. The worker, on the other hand, had no idea about what steps were needed to complete the task. In order to give users a better appreciation of our new 3D interface in relation to different design options, following the assembly task, the pair was given the opportunity to explore and experience different levels of immersion: 1) no stereoscopic vision, no head tracking and no hands shadow (2D interface), 2) stereoscopic vision, no head tracking and no hands shadow, 3) stereoscopic vision, head tracking and no hands shadow, and 4) stereoscopic vision, head tracking and hands shadow (full 3D interface). This last feature is one that was implemented in HandsIn3D and that participants used in the guiding task at the start of the trial.

Participants were required to complete worker and helper questionnaires after the assembly tasks. These questionnaires asked participants to rate a set of usability metrics, answer some open questions and share their experience of using the system. The usability measures include both commonly used ones and those specific to the system. For more details, see the Results subsection.

3.2

Procedure

The study was conducted a pair after another in a meeting room and was observed by an experimenter. The helper space and worker space were separated in a reasonable distance by a dividing board so that two participants could not see each other. Upon arrival, they were randomly assigned helper and worker roles and informed about the procedure of the study. The helper interface and the worker interface were introduced. They were also given the chance to get familiar with the system and try out the equipment. Then the helper was taken to an office room where he/she was shown a model that needed to be constructed. The helper was given time to think about and plan how to do it and remember the steps.

Then the helper went back to the experimental room and put the HMD on and the experiment started. After the assembly task, the pair of participants was asked to experience the different interface features listed in the last subsection in an informal style. The switch between the interface features was controlled by the experimenter. During the process, the participants were told which feature the system was using. They could play with the toy blocks and talk to each other about the assembly steps. But they were not allowed to comment and share how they felt about the system and the features. This was to ensure that their later responses to the questionnaires were not affected by each other's partner and were of their own. After going through all four features, each participant was asked to fill the helper or worker questionnaire for the role played. Then the participants switched roles and the above process was repeated again. Note that this time the model to be constructed was different but with a similar level of complexity.

After finishing the assembly tasks and questionnaires, participants were debriefed about the purposes of the study, followed by a semi-structured interview. They were encouraged to share their experiences, comments on the system, ask questions and suggest improvements. The whole session took about one hour on average.

Results and Discussion

Observations. It was observed at the beginning, some participants were very shy about wearing a HMD, resulting in very few head movements. Participants needed prompting and encouragement in order to start moving their head around and change their field of view. This indicates that users may need to take some time to get used to system, as one user commented: "It took me about 10 seconds to adapt to the 3D viewpoints. But after that everything is fine." Apart from this, all pairs of the participants were able to complete their assigned tasks without apparent difficulties. Their communications seemed smooth. Both helpers and workers looked comfortable performing tasks with the system. More specifically, workers were able to follow the verbal instructions from helpers and understand what they were asked to do by looking at the visual aids shown on the screen. Helpers were able to guide workers through the task process with the HMD worn on their head and using hand gestures. Usability Ratings. Fourteen participants filled two questionnaires each: the helper questionnaire and the worker questionnaire. We had 28 responses in total. A set of usability measures were rated based on a scale of 1 to 7 with 1 being strongly negative, 7 being strongly positive and 4 being neutral; the higher the rating is, the better the usability. The average ratings are illustrated in Figure 3. Note that 1) helpers had two extra items to rate: perception of spatial relationship between objects and sense of immersion; 2) due to the space limitations, we only report here the ratings of the full 3D system.

Fig. 3. Average user ratings

As can be seen from Figure 3, despite the slight variations between helpers and workers and across usability items, all items were rated greater than 4, indicating that participants were generally positive about the system. Further, helpers rated the system relatively low for its learning and usage compared to workers. While the system made workers more satisfied with their own individual performance, helpers were more satisfied with the overall group performance. In addition, while helpers gave the same rating for being able to perform both pointing and representational gestures, workers seemed to perceive pointing gestures more easily than representational gestures.

In regard to co-presence, both ratings were over 5, which were higher than those reported by Huang and Alem [START_REF] Huang | Supporting Hand Gestures in Mobile Remote Collaboration: A Usability Evaluation[END_REF] (just above 4). This indicates that our 3D system offered a higher sense of "being together" for participants. When compared to workers, helpers reported a relatively higher sense of co-presence. Helpers also had positive ratings for perception of object spatial relation and sense of immersion. All these indicate that our 3D design approach did work as expected.

User Experiences. Based on user responses to the open questions and user interviews, participants were generally positive about the system, as one participant stated that "it is very impressive and a great experience to use this system."

More specifically, participants appreciated the feature that workers are able to see and helpers are able to perform hand gestures. A helper commented that "he (the worker) knew exactly what I meant by 'here', 'this one' and 'that one'." A number of workers simply commented that "(hand gestures were) easy to understand and follow."

Consistent with the usability ratings, the 3D interface has boosted a strong sense of co-presence and immersion for helpers. It was commented that the system had given participants a feeling of being in front of the remote workspace and co-presenting with the remote objects and their remote partner. Comments from helpers include "I feel I was right there at the screen and really wanted to grab the objects." and "I can feel that her hand was in my way, or my hand was in her way. So in this sense, I felt we were in the same space." A few workers also commented that seeing both hands in the field and using words like "this" and "that" during the conversation made a strong visual impression and physical presence.

User comments also provide further evidence that the 3D interface improved perception of spatial relation and participants appreciated that. For example, "You can see the difference between 2 objects with the same base but different heights in 3D." "3D helped to see how the final shape looked. With 2D, I had to ask the worker to show me the piece in another angle." "It gives the depth of the objects, so remote guiding could be easier in some cases."

Participants generally liked the idea of having shadows of hand and objects, commenting that it would be easier to point and gesture in the remote workspace as hand shadows could provide them with an indication of hand location in relation to the remote objects. However, there were mixed responses when participants were asked whether the shadow feature actually helped. For example, "Yes, it helps. It makes a good stimulation effect. So I can do better communication with my partner." "The shadow helps me feel that the view is in 3D. But I think I can still understand without the shadow." "No, there are some real shadows in grey color. The black shadow is artificial and a little bit annoying." "The shadow could sometime cover objects and I think this could potentially lead to something wrong (maybe a transparent shadow)." "Yes, (shadow helps) for pointing only, but not much on rotating etc."

In regard to head tracking, participants commented that it enables helpers to see more of the way that blocks are connected without needing their partner to rotate them and that it makes workers aware of what helpers are looking at.

Further, in comparison with the 2D interface, participants commented that 2D is fine with simple tasks, but 3D offers much richer user experience and is more preferable and useful for complex procedures when a high level of user engagement is required. For example, "3D is more realistic as I can see all angles." "In 2D, it seems like playing a game. When changing my viewpoints into 3D, I got a feeling of going back to real world." "(3D) helps more when I need to give instruction related to space concept." "3D interface makes it easy to match the screen and the physical objects." "3D feels real. 2D interface is enough for simple tasks but 3D interface helps more when the task gets more complicated."

Although the main purpose was to test the usability and usefulness of our 3D concept for remote guidance on physical tasks, user comments also gave some hints for further improvements and more features. These include 1) use a lighter and more easily adjustable helmet; 2) increase image quality and resolutions; 3) differentiate worker and helper hands by color and make them transparent; 4) provide a more dynamic and more immersive environment for helpers to interact with, such as when the helper moves closer to the objects, they become bigger; 5) enable helpers to have access to manuals while guiding; 6) make shadows grey and transparent.

Concluding Remarks

Our user study has showed that the proposed 3D immersive interface is helpful for improving perception of spatial relation of helpers and sense of co-presence and that the system is generally useful and usable, particularly more so for complex tasks.

The study also points out some future research and development directions. We plan to advance the prototype into a close-to-production system so that we can test it in a more realistic setting. For example, separate the two sides of the system and connect them through the internet, instead of hosting them by the same PC. We also plan to compare HandsIn3D with its 2D versions through rigorously controlled studies so that we can have more quantitative and objective information about the benefits of immersive virtual environments in supporting remote guidance.

Fig. 1 .

 1 Fig. 1. Worker space (left) and helper space (right)


Steven Neale
email: steven.neale@utas.edu.au

Winyu Chinthammit
email: winyu.chinthammit@utas.edu.au

Christopher Lueg
email: christopher.lueg@utas.edu.au

Paddy Nixon
email: paddy.nixon@utas.edu.au

RelicPad: A Hands-On, Mobile Approach to Collaborative Exploration of Virtual Museum Artifacts

Keywords: Museum artefacts, remote collaboration, tablet interfaces, 3D interaction techniques, virtual reality

In an ideal world, physical museum artefacts could be touched, handled, examined and passed between interested viewers by hand. Unfortunately, this is not always possible -artefacts may be too fragile to handle or pass around, or groups of people with mutual interests in objects may not be in the same location. This can be problematic when attempting to explain or make sense of the physical properties of artefacts.

To address these problems, we propose that direct manipulation of 3D content based on real-world interaction metaphors can help collaborators (both co and remotely located) to construct personal and mutual physical and spatial awareness of artefacts, while networked communication and collaboration allow for ideas and knowledge to be exchanged and shared. We present our interpretations from two studies of RelicPad, a tablet-based application that allows users to manually manipulate museum artefacts and to 'point out' areas of interest to each other using 3D annotations, facilitating a mutual awareness of spatial properties and referencing during discussion.

Introduction

Handling physical museum artefacts is acknowledged as being a powerful experience. As objects with meaning, artefacts help to create "strong personal connections" to pasts and people across time and culture, prompting thought, memory and understanding [START_REF] Boyes | In the Hand -The Effect of Museum Handling Sessions on Student Learning[END_REF]. This makes it particularly useful to have artefacts at hand when discussing them or explaining them to other people. However, in situations where handling artefacts is not possible (objects being enclosed in display cases, too fragile or valuable to be handled, or located in a different part of the world), the vital spatial referencing and physical understanding that handling artefacts provides is lost.

The Queen Victoria Museum & Art Gallery (QVMAG) [START_REF] Victoria | [END_REF] in Launceston, Tasmania, who provided resources for our research, described to us an example scenario of museum curators considering the purchase of an artefact from an overseas museum. With time, money, and effort at stake, it is hugely advantageous for curators to be able to understand the physical properties of artefacts before committing to a decision, even if they are not able to handle them in person. Other scenarios within the problem domain include the discussion of artefacts amongst online communities (digital museum visitors), between curators in different museums around the world, long distance lectures, and presentations.

This paper describes an initial design and evaluations of RelicPad, a tablet-based application that addresses this problem by facilitating physical, reality-based interaction with and collaborative discussion of virtual (3D representations of) museum artefacts. In collaboration with the QVMAG, a piece of nineteenth century scrimshaw (scrollwork, engravings, and carvings done in bone or ivory [START_REF]Scrimshaw[END_REF]) has been rendered in 3D for exploration and discussion using RelicPad. During a discussion, users:

• Manipulate the virtual museum artefact by using their hands to manually interact with the tablet. • Leave 3D markers (referred to in this paper as 'interest points') on different parts of the virtual museum artefact.

These features allow users to manually manipulate a virtual museum artefact and to 'point' to specific areas of interest, despite not being able to see the actions and gestures of others. This allows users to construct their own awareness of an artefact's physical and spatial properties and to communicate spatial references for others.

We first describe our motivation for the research, and present some related work. Next, we describe the application and provide an overview of its functionality. We then introduce and present the results of our two studies, and offer a discussion of our findings. Finally, we draw conclusions based on our interpretations of the discussion and finish by outlining our future work.

Motivation

While replicating the experience of physically handling an artefact is impossible, our research presents an alternative approach to making sense of artefacts through exploration and collaborative discussion, based on 3D representations of their physical properties. As well as the loss of the tactile and physical understanding and sensation that comes from handling objects individually, it is also problematic for collaborators to convey gestural clues about the spatial relationships between themselves and the objects around them without mutual access to objects [START_REF] Everitt | Two Worlds Apart: Bridging the Gap Between Physical and Virtual Media for Distributed Design Collaboration[END_REF], making it difficult for individuals in different locations to maintain focus on them.

Our research is aimed at providing a usable application for a number of different museum user groups, including researchers, curators, educators, and visitors (both physical and online). Each of these groups has their own sets of motivations for engaging with artefacts -overseeing and caring for collections, organising educational programs, public service and community outreach, authenticating, evaluating and categorizing artefacts, presenting information to the public, or receiving information from the museum institution [5] [6] [START_REF] Simon | What's a Virtual Visitor Worth?[END_REF]. The unifying thread between users in these groups is that they all have the desire to engage with artefacts, and that they all have opinions, ideas, or knowledge to share, drawing on everything from culture and personal experience to specialized training or knowledge. We believe that this makes a usable tool for exploration and collaborative discussion of virtual museum artefacts an exciting prospect for users across the whole spectrum of museum user groups.

It has been suggested that task environments have an outer boundary of what is visible to the person(s) carrying out the task, known as the 'horizon of observation' [START_REF] Hutchins | Cognition in the Wild[END_REF]. Naturally, how an interactive system makes use of this boundary, particularly for collaboration, is going to have "consequences for the process of acquiring knowledge" [START_REF] Hutchins | Cognition in the Wild[END_REF]. However, there are many situations where the horizon of observation around an artefact is too limited to be able to fully explore or understand it. Artefacts themselves are often enclosed and cannot be seen or touched from all sides; if passed around between large groups (of museum visitors, for example), only smaller subgroups of people will have good access to it at any given time; online visitors may only have access to still images via museum websites; and in remote-collaborative situations, even if one collaborator has access to the artefact, the rest of the collaborators will be limited to what is described to them by voice, shown to them as still images, or in the case of videoconferencing held up in front of a camera.

RelicPad expands this 'horizon of observation' in ways not normally possible with existing technologies, supporting real-time exploration of a virtual museum artefact and collaboration with others, and allowing users to easily focus, communicate and discuss ideas and theories about artefacts in a 3D context. As a mobile, tablet-based application, RelicPad is also adaptable to numerous collaborative scenarios, from passing one or more tablets around a large group of museum visitors to remote collaboration by way of real-time networked interaction. Putting the task 'in the hands' using the mobile context makes the 'horizon of observation' or 'window' to the artefact applicable to different groups of people working across varied contexts of use.

Related Work

As outlined in the introduction, handling physical museum artefacts is a powerful experience, linking the handler to individuals and periods of time that they would otherwise have no tangible contact with [START_REF] Mastoris | Learning Through Objects[END_REF]. This is largely down to the sensory qualities of artefacts -they are "a 3D experience", more tactile than a still image or a recording, and can be turned over and viewed from all sides [START_REF] Mastoris | Learning Through Objects[END_REF], providing handlers with "significant insight and understanding of the physical and material aspects of objects" [START_REF] Boyes | In the Hand -The Effect of Museum Handling Sessions on Student Learning[END_REF]. While simultaneously replicating all of the sensory qualities associated with handling artefacts is not a realistic aim, tablets provide a method of displaying a high-quality 3D rendering of a museum artefact, and of using different interaction techniques to view it from all sides.

3D scanning of museum artefacts is now "a practical reality" [10], providing a wealth of 3D museum content for exploration and discussion. The challenge is interacting with this content in a way that better represents the manual exploration that users expect from traditional object handling. Tangible interactions using devices such as tablets and touchscreens might better represent certain interaction concepts than a mouse is able to [START_REF] Manches | Designing Learning Representations Around Physical Manipulation: Hands and Objects[END_REF]. But while there has been plenty of research into interaction techniques for the manipulation of 3D virtual objects, their application to mobile devices such as smartphones and tablets remains a scarcely explored area.

Most interaction techniques developed "for stationary computers" are "not applicable" to such devices [START_REF] Henrysson | Experiments in 3D Interaction for Mobile Phone AR[END_REF], which seems a missed opportunity considering that the rapidly improved display capabilities of smartphones and tablets have made the delivery of rich, interactive 3D content very achievable. The University of Virginia Art Museum's (UVaM) Interactive iPad Museum Catalog [START_REF]Put 3D Objects at your Visitors' Fingertips: UVaM on the iPad, Idea.org[END_REF] allows users to view a number of pre-selected artifacts from the museum's collection as high-quality 3D visualizations, but interaction itself is limited to dragging the finger on a touchscreen to rotate around a single axis, and scaling. Explorations into manipulating 3D content on mobile devices have experimented with concepts such as 'tilting' devices using either computer-vision techniques [START_REF] Henrysson | Experiments in 3D Interaction for Mobile Phone AR[END_REF] or built-in sensors such as gyroscopes, compasses and accelerometers [START_REF] Kratz | PalmSpace: Continuous Around-Device Gestures vs. Multitouch for 3D Rotation Tasks on Mobile Devices[END_REF], which have proven to be a promising alternative to more traditional 2D interaction or touch techniques for 3D content rotation tasks.

But regardless of whether touch or tilt techniques are being used, we believe that the techniques used to manipulate virtual representations of objects should be based "on the real world" [START_REF] Jacob | Reality-Based Interaction: Unifying the New Generation of Interaction Styles[END_REF]. When the user is already skilled at performing the actions that underpin the basic operation of the system, the "mental effort required" for that operation can be significantly reduced [START_REF] Jacob | Reality-Based Interaction: Unifying the New Generation of Interaction Styles[END_REF], and so a strong representational metaphor of object handling, requiring minimal thought and leaving users free to focus their attention on the physical nuances of the object (and collaborative discussion) rather than how to manipulate it, should be considered as part of the interaction technique.

As important as the manipulation of the virtual museum artefact are the interactions for supporting and organizing discussion between collaborators, particularly remotely. Physical objects can play an important role in collaboration. As well as using them to "complete their own activities", collaborators often use objects to "coordinate [these activities] in real-time with the conduct of others" [START_REF] Hindmarsh | Object-Focused Interaction in Collaborative Virtual Environments[END_REF], and it has been suggested that collaboration "relies upon [collaborators'] mundane abilities to develop and sustain mutually compatible, even reciprocal, perspectives" of their environment and the objects within it [START_REF] Hindmarsh | Object-Focused Interaction in Collaborative Virtual Environments[END_REF]. Naturally, interaction with a virtual museum artefact needs to support similar processes of understanding and referencing between collaborators, who may well be connected remotely and unable to see each other.

Common tools for collaboration and discussion (such as Skype or Windows Live Messenger) allow users to share and exchange files, view each others' screens, send instant messages, and communicate in real-time using both voice and video. Existing research into remote collaboration systems has shown tags, metadata and annotations to be useful in mutually focusing attention for 2D data (e.g. text, images and video). In museum informatics, distributed systems for sharing information about artefacts and collections are a well-researched area in their own right, with various web [START_REF] Goodman | Architecting CollectionSpace: A Web-Based Collections Management and Information System for 21st Century Museum Professionals[END_REF] and multi-media [START_REF] Oomen | Sharing Cultural Heritage the Linked Open Data Way: Why You Should Sign Up[END_REF] based approaches that encourage and facilitate the distribution of that museum data across as wide a museum community as possible.

Visual media in such systems are generally 2D, and interactive content (beyond basic text, images and video) is limited. 2D interactions such as clicking images and following hyperlinks reflect this and there are few examples of these principles being used in 3D contexts, leaving these technologies with a very fixed horizon of observation that can only be pushed so far. However, we now have such a wealth of available technologies for displaying and interacting with 3D content that interactive systems for remote collaboration could be making far better use of the visual channels available to them, particularly where the spatial referencing of 3D objects is concerned.

Annotations are a common feature of collaborative technologies, and increasing interactivity has seen annotations move from being solely about "managing data and metadata" to becoming "critical" resources in "supporting communicative practice" [START_REF] Fraser | Remote Collaboration Over Video Data: Towards Real-Time E-Social Science[END_REF]. The Vannotea system used annotations as 'metadata stores' to enable "the collaborative indexing, browsing, annotation and discussion of [video] content between multiple groups at remote locations" [START_REF] Schroeter | Vannotea -A Collaborative Video Indexing, Annotation and Discussion System for Broadband Networks[END_REF], while the Kinected Conference sees annotations used to convey users' whereabouts in 3D, using video depth, audio cues and face-tracking algorithms to assign dynamic and interactive context tags to remote collaborators in a videoconference [START_REF] Devincenzi | Kinected Conference: Augmenting Video Imaging with Calibrated Depth and Audio[END_REF].

As well as creative and interactive uses of annotations for spatial referencing in remote collaboration, there are also examples of previous attempts to expand the 'horizon of observation' around 3D virtual content. Lighthouse, a remotecollaborative system for troubleshooting printer problems, used synchronized 3D representations of printers visible to both the customer and the troubleshooter, allowing troubleshooters to manipulate a shared pointer to highlight problems with the printer for the customer [START_REF] O'neill | From Ethnographic Study to Mixed Reality: A Remote Collaborative Troubleshooting System[END_REF]. However, even systems like Lighthouse still use a mouse and keyboard (2D interfaces) as the input methods for interactions with 3D content, and so there is room to explore how collaboration, discussion and annotation can be integrated with 3D object manipulation to expand the horizon of observation around virtual museum artefacts for exploration and discussion by multiple (remote) collaborators.

Description of RelicPad

Research suggests that the actions generated by physical manipulation of tangible interfaces help to "draw up previous knowledge" and "generate important motoric representations to support other forms of representation" [START_REF] Manches | Designing Learning Representations Around Physical Manipulation: Hands and Objects[END_REF]. Based on the idea that manually manipulating virtual artefacts and marking interest points supports the exploration and discussion of objects (just as physically handling an object helps to build context) and supported by our review of the problem area and related work, our approach was to develop an initial prototype for RelicPad (described in this section) and then to identify, explore and evaluate design issues through a series of user studies (sections 5 & 6).

4.1

Overview of RelicPad Features

As well as the application to user groups from a variety of museum contexts outlined in our motivations, the clear benefits of being able to physically manipulate the interface influenced our decision to use a mobile, tablet-based platform as the interface technology for our research. Tablets also have a unified input and output space; the interaction and the resulting action happen in the same place (usually the hands), and so the observation viewpoint is the same as when handling a physical object.

RelicPad aims to provide a digital alternative to two key physical interactionsphysically moving an object around in the hands, and pointing at different areas of objects. Taking into account the underlying aim of enabling users to share information about these 3D artefacts, RelicPad can be broken down into three fundamental elements that underpin the application:

• Manipulation (rotation and scaling) of the virtual museum artefact in 3D.

• Real-time marking of interest points in 3D space.

• Interactive conversation history.

These three elements offer digital representations of physical object handling, pointing, and organizing topics of discussion, enabling users to explore and discuss virtual museum artefacts in collaborative scenarios. Users can manipulate (rotate and scale) the virtual artefact using their hands to build up an understanding of it in 3D, can mark interest points to show each other where (and in what context) something interests them, and can refer to a conversation history to remind themselves of how conclusions were made and revisit earlier topics of interest. An example of how these elements come together in the interface can be seen in Figure 1:

Manipulation of the Virtual Museum Artefact in 3D.

In order to expand the 'horizon of observation' around virtual museum artefacts in ways that current applications do not, it is important to ground these digital interactions in reality-based movements that are more akin to handling physical objects. It is largely the 3D experience of handling physical objects -turning them over, looking inside them, viewing them from all angles -that prompts thought and understanding, helping the handler to make sense of the object [START_REF] Boyes | In the Hand -The Effect of Museum Handling Sessions on Student Learning[END_REF]. Finding an appropriate interaction metaphor that gives users freedom and control over the manipulation (rotation and scaling) of the virtual museum artefact is important.

Our research has looked at two interaction metaphors for manually manipulating 3D objects using a tablet as the interaction device -tilt and touch (Figure 2): The tilt metaphor works by using the orientation of the tablet, given by the built-in accelerometer and gyroscope, to calculate the orientation of the 3D content, and represents the idea of using the hands simultaneously to grasp a physical object and rotate, twist, and turn it around. Visually, it carries a strong representation of moving a physical object with both hands. In contrast, the 'touch' metaphor works by orientating the 3D content according to the position of the user's finger(s) on the device's screen, representing something more akin to holding a physical object (in this case the tablet) in one hand, and using the other to rotate, twist or turn the object within that hand. Although more visually abstract than the tilt, this is a more familiar and traditional tablet interaction technique.

Section 6 describes the second study undertaken as part of this research, a comparison between four different techniques for rotating the 3D artefact (two techniques for each of the two interaction metaphors described above) and three different techniques for scaling the 3D artefact, and outlines each of these techniques in more detail.

Marking of Interest Points.

With physical objects, people point at them to provide each other with a clear frame of reference and to clarify areas of interest. Pointing is a clear visual gesture that draws attention to something that is deemed to be interesting, and marking interest points with RelicPad supports discussion of virtual museum artefacts in the same way. Users attach interest points to virtual museum artefacts that other users can see for themselves in 3D space, in much the same way as people use pointing to guide others to what they want them to see during discussions about physical objects.

Marking interest points using RelicPad is achieved by tapping the screen on the area of the virtual museum artefact where the interest point is to be placed. As well as being a very familiar gesture to users of mobiles, tablets and touchscreens, the 'tap' gesture also resembles pointing in the physical and visual sense, making use of a single extended finger. Tapping the virtual museum artefact brings up a box menu with a choice of three possible 'context' icons (see Interactive Conversation History subsection below) plus a fourth 'cancel' icon in case the user decides not to leave the point after all. Tapping one of these icons leaves an interest point with the selected context in the desired location.

Above the choice of context icons is a text-field, allowing users to assign a keyword(s) to the interest point if they wish. Interest points themselves are offset slightly to the left or the right of the screen (depending on which side of the middle of the screen the user decided to leave the interest point) and linked to the virtual museum artefact by a line, so that when initially left they are not obscuring it.

Interactive Conversation History.

The interest points left during a discussion come together to form an interactive 'conversation history'. An important classification tool for this conversation history is the context that can be used to define an interest when it is being marked. There are three context choices available, representing aesthetics (something about the way the object looks that the user finds interesting), geometry (something about the shape of the object that the user finds interesting), or meaning (something that the user feels provides clues about the cultural significance or idea behind the object).

In addition to (optional) user provided keywords, the name of the user who left each interest point and the time at which it was left, the classification of context (identifiable by the look of the interest point) allows for a historical record of the activity in discussions, conversations and collaborations to be kept, organized according to the interest points users have created. For collaborative use, this provides "a persistent record of interaction and collaboration" that can be easily referred back to [START_REF] Stahl | Computer Supported Collaborative Learning[END_REF], enabling users to revisit earlier interest points and "remind [themselves] of the process by which they reached previous interim conclusions" [START_REF] Fraser | Remote Collaboration Over Video Data: Towards Real-Time E-Social Science[END_REF].

RelicPad's conversation history consists of a scrollable menu in the top-right hand corner of the screen that stores all of the interest points in a discussion, adding each new point at the top of the list. As well as the point's context icon, each interest point record in the conversation history also contains the keyword given (if any), the name of the user that left the point, and the time at which it was left. This interactive but relatively traditional two-dimensional list leaves the conversation history in the periphery of the user's attention until it is needed -users can focus on their exploration and discussion of the artefact and on the physical interactions used to operate other RelicPad features, but can refer back to earlier points of discussion when needed.

First Study -Communication and Collaboration Using RelicPad

Our first study aimed to get a feel for RelicPad as a user experience, and give an early indication of how useful it could be in context. The idea was to find out if participants could, by connecting to each other remotely using RelicPad, discuss an artefact together, share ideas about it, and draw each other's attention to its various features, in order to arrive at a conclusion about what the artefact is.

Experiment

We invited 22 participants, not selected based on any specific criteria, to take part in 11 collaboration sessions (2 'remote' collaborators discussing the virtual museum artefact with each other in each session). Rather than specifically recruit participants from any of the previously described museum user groups, we opted for participants with no prior knowledge of the artefact so that as opposed to relying on any preexisting knowledge of what the artefact might be, they would use interest points and spatial referencing to collaboratively generate and share ideas and understanding. This scenario of 'exploring from scratch' is applicable to any of the museum user groups, even curators and researchers who regardless of knowledge and experience will still be presented with new and exciting objects to make sense of from time to time.

Participants were each given an iPad running RelicPad with our 3D model of the QVMAG's scrimshaw piece loaded as the virtual museum artefact. Prior to the experiment, we identified (in collaboration with QVMAG curators) 7 key features of the scrimshaw piece that we expected participants might be able to identify together. During the sessions, participants were encouraged to talk to each other, share ideas, and mark interest points in order to form conclusions about what the artefact is, where it came from, and the story behind it. We anticipated that our subsequent data collection would shed some light on how they had used RelicPad's features to do this.

Each experiment lasted for approximately 30 minutes -10 minutes introduction and explanation, 10 minutes for the collaboration session, and 10 minutes to complete the subsequent questionnaire. Participants were seated opposite each other at adjacent desks, with a large screen obscuring their views of each other -they were able to hear each other as they would during a phone call or videoconference, but were unable to see each other's movements, gestures, or interactions with the tablet. The investigator was seated to the side of the participants, with a clear view of both of them for making observations. Data was recorded as a sequential analysis of activity and interaction between the participants, accompanied by questionnaires. The sequential analysis consisted of three elements -an audio recording of each discussion session, a log of interactions recorded by the iPads and stored in an online database (recording when an interest point was left, as well as the context and any keywords that were given to it), and handwritten observations made by the investigator of notable exchanges between the participants during each session. These three elements were time synchronized to paint a picture of how and why participants came to different conclusions using RelicPad, and how RelicPad features were used in this process.

The questionnaires, given to each participant after the discussion was over, consisted of two sets of ten questions adapted from the System Usability Scale (SUS), a widely accepted, "simple, ten-item scale giving a global view of subjective assessments of usability" [START_REF] Brooke | SUS -A Quick and Dirty Usability Scale[END_REF], the answers from which can be used to generate a single number representing "a composite measure of the overall usability of the system being studied" [START_REF] Brooke | SUS -A Quick and Dirty Usability Scale[END_REF]. The first ten questions focused on the five basic factors of usability (effectiveness, efficiency, safety, utility and learnability) while the second ten questions focused on five core components of user engagement -identity, adaptivity, narrative, immersion and flow [START_REF] Benyon | Designing Interactive Systems -A Comprehensive Guide to HCI and Interaction Design[END_REF]. The remaining questions were a mixture of closed and open-ended questions seeking additional feedback on how users felt about different RelicPad features, what they felt they had learned from the collaboration, and their overall impressions of RelicPad as an experience.

During each session, participants were each given an iPad running a different version of the prototype. One participant was always using the tangible 'tilting' interaction method for rotating the virtual museum artefact, while the other participant was always using a more traditional 4-button 'directional pad' for rotating it. The tilt rotation was rate-controlled (the virtual museum artefact rotates faster according to how far the tablet is tilted), with a rotation button or 'clutch' held to initiate and released to cease rotation. The 4 directional buttons were used to rotate the artefact up or down around the x-axis, or left and right around the y-axis.

Neither participant knew that their collaborator was using a different technique to rotate the virtual museum artefact. The idea behind this was to evaluate whether or not there was any difference in how usable or engaging participants found RelicPad based on whether or not they used a physical, tangible rotation method, or a more traditional 2D interaction technique.

Results

Observations and audio recordings showed that during the 11 collaboration sessions, pairs of participants were able to arrive on average at 4.45 of the previously identified 7 conclusions about the scrimshaw. Certain things were particularly well noticed by participants, including faded lettering on the back of the scrimshaw (a focal point of the discussion in 10 of the 11 sessions) and the cracks in and discoloring of the scrimshaw (focal points of the discussion in 9 of the 11 sessions).

The combination of observations and activity logs gave an indication of how interest points are used during collaboration. On average, 12 interest points are left during each of the 11 sessions. Participants on average will specifically refer to 48% of these interest points, whether that be to tell their collaborator that they have just left (or are about to leave) the interest point, to tell them exactly what part of the artefact it is being attached to, or to give them directions to help them find out where it is. Participants also on average ask their collaborator for clarification or an explanation of 13% of interest points; asking where an interest point is, what it was supposed to be attached to, or whether they are looking at the correct one.

Questionnaire responses revealed a positive response to RelicPad. Although 8 out of the 22 participants unfortunately did not give a definitive answer to the question, 12 of the 14 participants who did respond described RelicPad as a positive experience. When asked to provide additional comments about the experience, 13 out of the 22 participants commented on the application being good for remote collaboration, conversation, and positional referencing, with 10 participants specifically referring to its suitability for interacting with artefacts in museum or educational contexts.

The first ten and second ten sets of questions were used to calculate single numbers for usability and user engagement, as described in the previous section. In both cases the mean scores were good -70.6 for usability and 73.07 for engagement. Participants were asked to rate RelicPad interactions based on how frequently they felt they used them (1 being very infrequently and 5 being very often). Results showed that on average participants felt that they had marked interest points very frequently (4.05), often added keywords to them (3.09), and occasionally chosen to change the current interest point (2.77) (to refer back to something from earlier in the discussion).

Participants were asked to rate how positive or negative they felt (5 being very positive) about the three fundamental elements that, as previously mentioned, combine to create the overall RelicPad experience -rotation of the virtual museum artefact in 3D, real-time marking of interest points, and the interactive conversation history. On average, the marking of interest points was the most popular feature among the participants (3.95), while rotation of the virtual museum artefact (3.82) and the interactive conversation history (3.32) were also both well received.

Second Study -Techniques for Manipulating Virtual Museum Artefacts

Separating the results of the first study according to which rotation technique was used, we found that there was no significant statistical difference between the tilt and directional button techniques, and conclusions about which technique was more usable or affected the experience differently to the other could not be drawn. Two-tailed independent t-tests proved this to be the case for basic usability (t=-.981, df 15.6, P=.342), user engagement (t=-.612, df 20, P=.547), ease of rotation (t=-1.64, df 20, P=0.116) and overall impressions of rotation (t=-2.01, df 20, P=0.058).

However, 'touch' and 'drag' interaction techniques (well established interactions with tablet devices) and a direct (one-to-one) mapping of tilt to rotation (as opposed to rate-controlled) were both suggested as ways of improving the rotation technique. This was interpreted as an indication that while the rate-controlled tilt was not significantly worse than a more traditional 2D interaction, it was not significantly better, leaving room for further exploration of interaction techniques and metaphors that might better represent the physical exploration associated with object handling.

Our second study compared four rotation techniques for manipulation of a 3D virtual object -two making use of the 'tilt' metaphor and two making use of the 'touch' metaphor (both metaphors are outlined in section 4). The two 'tilt' techniques were a rate-controlled tilt (the angle at which the device is tilted defines the speed at which the virtual object rotates) and a direct-mapping tilt (the virtual object's rotation follows the angle at which the device is tilted exactly). The two 'touch' rotation techniques were a 'virtual trackball' implementation (enclosing the virtual object in a sphere which is dragged with a single finger in order to rotate, described as a 'virtual sphere' in [START_REF] Chen | A Study in Interactive 3-D Rotation Using 2-D Control Devices[END_REF]) and a 'multi-touch' approach (dragging with a single finger to rotate the artefact on the x and y axes, and rotating two fingers clockwise or counterclockwise in order to rotate the artefact on the z axis).

Three techniques for scaling the virtual museum artefact were also compared -a 'plus & minus buttons' approach (holding one of two buttons to increase or decrease the scale of the artifact), a 'slider bar' approach (continuous dragging between the two end points on a slider bar widget to increase or decrease the scale), and a 'multitouch' approach (increasing or decreasing the distance between two fingers, also known as 'pinching' and 'spreading', to increase or decrease the scale of the artefact).

Experiment

12 participants took part in a set of 'object-matching' trials, using the different rotation and scaling techniques to match a virtual museum artefact (the scrimshaw piece from the first study) with a semi-transparent target orientation of the same artefact. The rotation techniques were organized according to a balanced Latin-square design (to minimize biases caused by practice or fatigue), and for each technique there were 18 trials -6 with each of the three scaling techniques. Of those 6 trials there were 2 simple, 2 medium and 2 complex rotation difficulties. Difficulty was defined as being whether matching the virtual artefacts required rotation on one (simple), two (medium), or all three axes. This makes a total of 72 trials per participant.

For each trial, participants' speed (time taken to complete the trial), rotation error (difference between virtual and target artefacts in degrees) and scale error (difference in size of the virtual and target artefacts represented as vectors) were recorded. Participants were asked to think about each trial in terms of both speed and accuracy and move onto the next trial as soon as they were happy. However, to keep things moving and prevent the experiment from taking an unreasonable amount of time, participants were asked to move onto the next trial after around 90 seconds.

In between each rotation technique (every 18 trials) participants were asked to answer some questions about that technique, and after all of the trials had been completed to answer questions looking back on all of the rotation and scaling techniques together. These questions asked participants to rate different aspects of the various techniques numerically, or to provide a few short sentences on the techniques.

The design of the experiment was based on a number of similar object-matching experiments from past research into techniques and technologies for 3D object manipulation, from early explorations with desktop-based VR systems [START_REF] Chen | A Study in Interactive 3-D Rotation Using 2-D Control Devices[END_REF] [27] [START_REF] Poupyrev | Non-Isomorphic 3D Rotational Techniques[END_REF], to more recent approaches to manipulating 3D content with mobile devices [START_REF] Henrysson | Experiments in 3D Interaction for Mobile Phone AR[END_REF] [14] and touch displays [START_REF] Martinet | The Effect of DOF Separation in 3D Manipulation Tasks with Multi-Touch Displays[END_REF].

6.3

Results

Table 1 shows means and standard deviations (SD) for how quickly and how accurately participants were able to complete the trials, on average, using each of the four rotation techniques -Rate-Controlled (RC) Tilt, Tilt with Direct Mapping (DM), the Virtual Trackball (VT) touch technique, and Multi-Touch. Touch techniques performed better than tilt techniques, being both quicker and more accurate to use: Analysis of variance showed the effects of rotation technique on both the time taken to complete the trials (F = 3.966, df 3, 68, P = 0.011) and on the average rotation error (F = 4.278, df 3, 68, P = 0.008) to be statistically significant.

A comparison of how quickly and accurately trials could be completed, on average, using each of the scaling techniques is shown in table 2 (means and standard deviations (SD)). Here, the touch technique performed better than its 2D counterparts, proving to be both the quickest and the most accurate technique: Analysis of variance shows the effects of scaling technique on the time taken to complete the trials to be of statistical significance (F = 3.857, df 2, 69, P = 0.026), but the effects of scaling technique on the average scaling error were minimal.

Comparing all combinations of rotation and scaling techniques together supports these results, with the combination of Multi-Touch rotation and Multi-Touch scaling resulting in the fastest average trial completion time at 41.61s (see Figure 3), the smallest average scaling error (3.93), and the second-smallest average rotation error (6.10 degrees). The worst combination was Tilt (Rate-Controlled) rotation with Plus & Minus Buttons for scaling, which gave the slowest average task completion time (64.65), largest average rotation error (19.69), and largest average scaling error (8.66). However, analysis of variance showed that apart from the Tilt (Rate-Controlled) rotation with Plus & Minus Buttons for scaling being by far the poorest combination of techniques, the differences between the rest of the combinations were minimal, and not of statistical significance. The questionnaires asked participants to rank the four rotation techniques in order from 1 (best) to 4 (worst) in relation to a number of different criteria, including: ease of rotation; perceived accuracy of rotation; perceived speed of trial completion; enjoyment; understanding of the movement of the artefact in 3D; perceived control over the artefact; and favourite technique. On average, Multi-Touch recorded the lowest (best) average (between 1.42 and 1.75) for all of the criteria, while Tilt (Rate-Controlled) recorded the highest (worst) average (between 2.92 and 3.33) for all of the criteria. Participants were also asked to rank the three rotation techniques in order from 1 (best) to 3 (worst) in relation to the same criteria -Multi-Touch scaling also recorded the lowest (best) average (between 1.42 and 1.92) for all of the criteria.

Discussion

Based on the results of the two studies, we have come to our own interpretations of how users have received our application, how applicable it is to the described problem domain, and which interaction metaphors give users the most control over the manipulation of virtual museum artefacts. We found that participants used interest points to share spatial references, that they could collaboratively construct solid ideas of what the artefact was, and that they felt positive about being able to rotate the virtual artefact in 3D, suggesting that RelicPad can facilitate exploration and collaborative discussion of virtual museum artefacts. We also found that touch interaction techniques leave users feeling in control of the manipulation of the virtual museum artefact.

In the first study, marking interest points proved to be the most popular and commonly used feature of RelicPad. Almost half of the interest points left were directly referred to by participants verbally, usually to explain what the interest point refers to as it is being left ("that there, it's a parasol"; "and you can see in this section here that it's lighter"; "down below there, that marking"; "it's broken, on your left side -I'll point it out for you"). This indicates that participants used the interest points for the purpose we intended -'pointing out' interesting areas or features of the artefact to assist each other in maintaining a shared spatial reference of the topic of discussion.

Importantly, participants noticed and discussed most of the things that were identified prior to the experiment as providing the history, story and significance of the scrimshaw piece. This indicates that participants not only enjoyed marking interest points, but that they used them for the intended purpose and that this bore results in terms of the collaboration. This is especially interesting given that to most participants it was not obvious from the start that the artefact was scrimshaw; it was through discussion and theorizing with each other that they were able to come to conclusions about what it was or wasn't. It did appear, however, that there was a tendency to notice visual stimuli, however difficult to see, but not always to fully establish what they represented. The lettering on the back of the scrimshaw was discussed at length in 10 out of the 11 sessions, but in only 3 of those 10 was it agreed that they could be the initials of the creator (or the recipient) of the scrimshaw.

The first study compared the rate-controlled tilt technique for rotating the virtual museum artefact against a directional button widget. With the initial design, the tilt was seen as being a strong visual representation of moving a museum artefact with the hands, but the difference in rotation method used seemed to have little impact on the usability of the application or what participants were able to made of the experience of interacting with the virtual artefact. The second study looked to explore alternative interaction metaphors for manipulating the virtual artefact, and to see what happened when scaling was brought into the picture as well as rotation.

Object matching trials comparing combinations of the different rotation and scaling techniques showed that touch techniques, particularly 'multi-touch' techniques, performed significantly better and were more popular than tilt techniques. Virtual objects could be rotated and scaled more quickly using touch techniques, and also with more accuracy. Participants also reported enjoying using them more, having a better understanding of how the virtual object moves in 3D using them, and crucially having more control over the virtual museum artefact.

A number of factors may contribute to this -tablets have weight, and physically rotating them for long periods of time was tiring for some participants. The issue of viewpoint may also play a part here -with touch techniques the observation viewpoint is fixed while the hands manipulate the virtual objects (more akin to kind of viewing angles associated with physical object handling), while with the tilt it could be thought of as being the opposite, with the hands moving the observation viewpoint as opposed to the virtual object itself.

We interpret this, coupled with the ability to accurately 'fine-tune' the position of the virtual artefact, as an indication that while the tilt metaphor carries a stronger visual representation of moving a physical object with the hands, the touch metaphor gives the user more control. By leveraging interactions styles that are familiar to many users, touch techniques and the control they provide leave users free to focus their attention on the content and the collaboration itself, rather than the techniques required to interact with the virtual artefact. As such, we believe that the touch meta-phor provides a more reality-based representation of natural and relatively thoughtless interaction with the hands for exploring the spatial properties of (virtual) artefacts.

Conclusions

Our interpretation of results shows that using interest points to draw attention to notable features of a virtual museum artefact helps users to understand and clarify areas of particular interest, and that over the course of a collaborative discussion these interest points are used to drive conversations and exchange ideas and theories. Participants in our study appeared to relish the ability to use the touch-tapping interaction to 'point' at artefacts and to highlight areas of interest for each other.

Comparing different metaphors for the manipulation of virtual museum artefacts suggested that established tablet interaction techniques such as multi-touch are the most efficient and enjoyable for controlling the manipulation of virtual museum artifacts on a tablet, leveraging skills that users are already familiar with to comfortably control the 3D experience and freeing them to focus their attention on other aspects of the system, such as marking and discussing points of interest.

We interpret this as an indication that for interaction techniques to feel 'realitybased', familiarity and control (moving an object in the hands comes naturally, as do touch techniques when using tablets) are perhaps more important than a strong visual representation (tilting the tablet looks more like handling an object, but it isn't the first thing people think to do with a tablet). This suggests an interesting compromise between how techniques look and how they feel when designing interactions.

As well as being well received as a positive experience by many participants, feedback showed that many of those participants saw the suitability of the application in museum contexts, specifically commenting that the application was good for remote collaboration and spatial referencing. RelicPad was able to expand each participant's horizon of observation in relation to both the virtual museum artefact itself and also to the focal points of each other's attention, and was used by participants to good effect. With the right interaction metaphors in place, it offers a promising solution to the scenarios presented in the introduction and motivation sections, and the example scenario provided by staff at the QVMAG.

Future Work

The experiments highlighted a number of interesting directions for the design of RelicPad. Many felt that the interest points themselves could have been more interactive -navigated to by touch, editable (renaming and deletion), more easily reidentifiable (either by keyword or by participant-based colour coding), and linked together to form a conversation thread. Combining the elements of interactivity from the conversation history into the interest points themselves may encourage collaborators to go beyond what they see of artefacts and to discuss further what those things might represent, giving spatial reference not only to areas of interest but to topics of interest as well.

In future experiments we also plan to evaluate whether the different museum user groups (or combinations of these groups) outlined earlier in the paper have different levels of success than others in coming to conclusions about artefacts whilst using the system. We will also compare the outcomes of collaborations made using RelicPad against those of face-to-face, co-located collaborations with the physical artefact to hand, and of existing remote-collaborative chat and video-conferencing alternatives such as Skype.

Fig. 1

 1 Fig.1 RelicPad interface; 3D representation of artefact (A), interest point (B), rotation button or 'clutch' (C), and interactive conversation history (D).

Fig. 2

 2 Fig.2 Two interaction metaphors -tilt (left) and touch (right).

Fig. 3

 3 Fig. 3 Graph showing average time taken to complete trials (in seconds) for each rotation technique, separated by scaling technique.

Table 1 .

 1 Speed and accuracy of the four compared rotation techniques.

	Averages	Tilt (RC)	Tilt (DM)	Touch (VT)	Multi-Touch
	Time Taken	58.03	51.75	49.72	47.99
	(seconds)	(SD 13.32)	(SD 14.59)	(SD 18.06)	(SD 10.84)
	Rotation Error	12.22	11.81	6.38	7.47
	(degrees)	(SD 9.92)	(SD 14.07)	(SD 3.91)	(SD 4.49)

Table 2 .

 2 Speed and accuracy of the three compared scaling techniques.

	Averages	+/-Buttons	Slider Bar	Multi-Touch
	Time Taken	56.08	50.91	48.62
	(seconds)	(SD 9.73)	(SD 7.34)	(SD 10.39)
	Scaling Error	7.03	6.63	4.65
	(size difference)	(SD 3.93)	(SD 4.07)	(SD 1.70)

Acknowledgements

Thanks go to Andrew Johnson and Jon Addison from the QVMAG for their enthusiasm and for permission to use one of their artefacts during the experiment, and to the Human-Computer Interaction research group at the University of Konstanz, Germany for help and resources during the second study. Thanks also to Bruce Andrews of the HIT Lab AU for his help with programming and development.