Design Decisions for a Brazilian t-Commerce Application

Nikolas Carneiro1, Anderson Marques1, Ranieri Teixeira1, Aruanda Meiguins2, Bianchi Meiguins1 Universidade Federal do Pará (UFPA)1, Rede de Informática Ltda.2

{nikolas.carneiro@gmail.com, anderson.gmarques@gmail.com, ranibtx@gmail.com, aruanda@redeinformatica.com.br, bianchi.serique@terra.com.br}

Abstract Digital TV interactivity implies a great potential for

social and digital inclusion, especially in a country like Brazil, where 95% of households have at least one TV. Due to the importance of Interactive Digital TV in this scenario, it is necessary not only to provide new applications to support services on TV, but also to evaluate the technological challenges and development practices, in order to provide viewers suitable interactivity considering the environment limitations. This paper presents the design process of a t-commerce application for the Brazilian iDTV middleware, the theories that based the development and an analysis of its appliance in a real scenario test.

Keywords: Interactive Digital TV, Ginga, t-

commerce, Information Visualization.

1. Introduction

The digital and social inclusion is a problem that Brazilian government has been investing in ways to solve. One of these ways is the definition and adoption of one middleware for digital interactivity on TV (iDTV), once that new environment, bring a high potential of popularization since 95% of Brazilian houses has at least one TV [1]. This approach also aims to add most of benefits provided by the web environment, as the rapid availability of applications, content and updates, possibility of access to content available from several sources and the ability to make collaborative the applications on the platform.

As well as the internet popularization took the migration of applications to web platform, the dissemination of interactive systems for TV, whether they are connected to TV (set-top boxes - STB) or embedded into them (interactive TVs), produce a proper environment to the migration of applications to support the services on iDTV platform. As an example has the e-commerce, a service widely used on web environment [2] which are linked to several auxiliary services and

applications, as security functions, inventory control, account tracking, etc.

Similarly to what happened to trade on the web, it is expected that the t-commerce, which is the marketing of products through interactive TV, to popularize. At first look, the major utility of t-commerce is the ability of the viewer to purchase a product that being released through a commercial, been this for general public or oriented through profile associated with set-top boxes [3].

But for this popularization to happen, it is necessary to evaluate the development of applications in this new scenario and further validate the decisions made based on user tests. To this end, this paper presents the research made for developing a t-commerce application using a visualization technique. We conducted non-oriented user tests in order to evaluate the development decisions and point which strategies are suitable for the Brazilian iDTV environment.

Section 2 briefly describes the Brazilian scenario of iDTV. Section 3 list works that contribute to the development of this project. Section 4 approaches some of the problems faced during this work, and the logic behind its resolution. Section 5 presents the tests designed to an preliminary evaluation of the application and the user results on the proposed tasks. Section 6 bring some final considerations about the application effectiveness and its use as an entry point for IV (Information Visualization) and iDTV.

2. Interactive Digital TV in Brazil

To provide a better understand about the decisions made during the design process we should first look at the scenario in which the application was designed.

To avoid excessive costs, the Brazilian Digital TV System was based on the Japanese system (ISDB-T), but with architectural changes to fit it for the Brazilian needs. One of these changes is the middleware, which was entirely defined in Brazil and focus on interactivity, the Ginga middleware [4].

Ginga is a free middleware which provides support for both declarative and imperative applications, respectively through its sub-systems, Ginag-NCL and Ginga-J.

2012 16th International Conference on Information Visualisation

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DOI 10.1109/IV.2012.39

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Although the Ginga-J is a procedural environment, and then, more suitable for an application that generates the user interface dynamically, its late development stage makes the adoption of this system a problem, since it is not fully implemented in all Ginga supporting STBs [4]. On the other hand, the Ginga-NCL is well defined, consolidated and all the Ginga STBs are demanded to fully support it.

In Brazil, the concept of interactive TV may be slightly misplaced, once there are programs where the viewer are able to participate in the program using other means, like phone calls, sms messages, etc. Other noticeable situation is that some users are very restrictive about the use of the TV, these ones keep themselves strictly to the change channel and volume of the TV, showing difficulty to perform other interactions.

Considering the number of Brazilian households with TV access [1], the actions from the Brazilian government to facilitate internet access and the under development laws to force Ginga support in TV devices to be produced, there is place for this kind of access become a great entrance for digital inclusion.

3. Related Work

By the time we are working on this project, no other work that uses information visualization on iDTV was found. Even so, we select some works that were valuable to this research and in the end, the work that originated this paper.

3.1. LuaOnTV

The LuaOnTV [5] project is a Lua framework that offers gui components to be rendered on Lua, allowing developers to dynamically generate user interfaces. The great challenge to overcome in this work was implement and use object oriented components with acceptable performance. Unfortunately, the project version 1.0 shows performance issues and bugs and its development is now discontinued.

3.2. Conceptual Models for T-Commerce in Brazil

Ghisi [6] defines a t-commerce model based in three characteristics: presentation, payment form and associative content. The author's definitions about presentation and associative content were important in order to define a scope for this work prototype.

3.3. Development of a System Providing a Personalized Yellow Page Service Based on an Interactive Video Application Service

This work [7] presents a personalized yellow page service through the IPTV (Internet Protocol Television)

environment. The main contribution from this work was present a commerce application that is directly interactive through the TV.

3.4. A Visualization Interface Applied in the Brazilian T-Commerce Scenario

Marques [8] presents an application in t-commerce support that uses the treemap [9] [10] [11] technique to provide a better way for viewers to compare and chose products.

This work is an extension on Marques research to offer an information visualization application for t-commerce support. While [8] focus on the application itself, this paper is mainly about the decisions that guided the development and the validation of these decisions through user tests. The interface of the application are show in Figure 1.

Figure 1: the Marques [8] version for the

interface, presenting configuration of colors but absent captions.

There are a few differences in the user interface of

the application from what is seemed in [8] and how it is presented here.

The main differences are about the inclusion of captions to help the viewer to remember previous configurations and the removal of the option to configure colors.

The colors configuration was removed because there is no proper control to handle continuous data that fit the interactions available using the remote control. To not interfere with the test we decide to take this functionality out for these tests.

Other change is that the interface now provides feedback about products that are in the cart. There is a counter indicating the amount of items in the cart and these items are drawn in a different color from the rest of the items in the treemap.

Figure 2 shows the interface as used in this paper's tests. The areas that changed are highlighted. In the control's area there are no longer buttons for setting color (since this functionality are no longer available) and to exit (this functionality is now activated in a context

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colored control key). The "Buy" button in the interface is now "Cart" and it also counts the number of products in the cart. The highlighted differences are in the bottom of the interface, controls in the right and caption below the treemap.

Figure 2: the new interface, captions and less

buttons.

4. Design Decisions

This paper presents a prototype to easy the choose of products while buying through the TV, using an IV technique. However, this project also intends to evaluate and validate techniques to develop IV tools for the Brazilian iDTV scenario.

In order to use IV concepts we have to adapt them to the environment particularities, since these concepts usually demands lots of computational power and precise interaction mechanisms, which ones are not available in the iDTV environment.

To guide these adaptations we considered both technical and contextual particularities, listing the following five characteristics as major guides during the design of the prototype:

• Environment functionalities: to assure the prototype would work properly in every device supporting GINGA, it was necessary use only pure resources from NCL and Lua languages. It prevents the use of third part APIs, once some of them make use of non-native resources.

• Environment limitations: once there are severe hardware limitations on GINGA Set-top Boxes, it was necessary to keep the processing and memory consume as low as possible.

• Untrained user: because of the nature of the application and the way it is made available, there will be a huge variety of user profiles and this one's should possibly get the application without any prior training, since they will get it together with the TV programs.

• User motivation: due to the limitation in the interaction device, navigate over lots of items can become tiring for the user and represent a discouraging factor for using the prototype.

• Usage scope: it defines how to handle the application in terms of storage, according to its relation with content being transmitted through TV. Morris [12], propose a classification for iDTV applications based on this relation.

4.1. Life cycle

Being an application for sales, there is no reason for keeping it into the STB once its content is out. Discarding the app after use is also useful to free space into the STB, once it is very limited on these devices.

The application suits for the Service Bounds applications class, according to Morris [12]. Even its usage is dependant from the content show on TV, the application generates its interface according to the data loaded and its process is independent of the meaning of these data, allowing the application to be transmitted many times, even sequentially, with no code changes.

Considering this, the application is only available to be started during the commercial its data is related to. If it is started its available until the user decide to end it.

Besides the memory consumption question, the application should not remain in the viewer STB because its data can run outdate and the product information on the STB may be no longer correct.

4.2. Navigation

In tree visualization techniques [13] the most common way to navigate is using pointing devices (mice, touchscreens, etc..), through the actions of drag and drop, click and mouse hover. However, the Ginga does not foresee any pointing device in its definition, making the arrows on the remote control the most friendly way to navigate on the display.

Taking into account the motivation and the lack of prior user training, we defined a unique navigation model for both visualization and controls in the user interface. This model is an adaptation based in the tree hierarchy [14], where a hierarchical level of the tree only becomes accessible through its parent node.

In this model, each interactive component in the GUI of the prototype is a node in the tree and you can walk across the nodes of a tree level using the arrow keys on the remote control, to interact with the children of a node, it is necessary to "enter" at that node.

Each node is a rectangular area and sibling nodes are located based on the direction of the arrow pressed and its position in the interface. When an arrow is pressed, the sibling node that is at mid-height and in the direction of the arrow is selected. In case there is no eligible node, i.e., there is no node who fit in the characteristics of the "move", the selected node remains the same.

Beside the fact that this approach allows to handle visualization and controls in the same way, it is also useful, in some cases, for reducing the number of

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interactions required to navigate from a an item in the treemap to another.

The number of interaction navigating hierarchically over treemap falls as much as the data is grouped compared to navigating plainly. The following example demonstrate the decrease in interaction effort using the same treemap configuration using hierarchically navigation. Once there is no prior training to the viewer, both paths are traced in reading order, i.e., from left to right and from top to bottom.

Figure 3: path from nodes A to B in plain

navigation.

Figure 3 exemplifies the path needed to go from an

A item to a B item in plain navigation. The following set of key pressings are needed: �, �, �, �, �, �, �, �, �, �, �, �, �, �, � and �. In a total amount of 16 key pressings.

Figure 4: path from node A to B in hierarchical

navigation

Figure 4 demonstrate the path along the same two

items using hierarchical navigation. Since we use the hierarchy of the treemap the keys for entre a group (ENTER) and leaving it (LEAVE) are used with the

arrow keyes It use the following set of key pressings: LEAVE, �, �, �, ENTER, �, �, � and �. In a total of 9 key pressings.

Generally while using hierarchical navigation, as more grouped the treemap are and more items it represents, increase the diference of number of interaction to go from one item to another in other group.

4.3. Viewer support

Once the viewer has no previous use of the application and there is the possibility of configuring the visualization technique, it becomes necessary to provide run-time instructions and subtitles to guide the viewer.

As the subtitle refers directly to visualization, we chose to keep it right below the treemap, as show in Figure 1. They are intended to remind the user of the settings made. The instructions for use are in the area above the configurations buttons.

The application also keep track of the products in the cart for the user. The user is told how many items, are in the cart and these items gain a different color in the treemap. To spare space, this information is displayed as a simple counter in the chart button.

In addition, the viewer does not lose the visibility of what is being shown on TV. The video programming is scaled to the top right corner of the application, occupying approximately 10% of screen space, and audio is maintained. Thus, even if the viewer spend a lot of time choosing products, the channel programming will always be present.

5. User tests

The tests were conducted with nineteen users, from 5 different age ranges: from 15 to 25 years, from 26 to 35, from 36 to 45, from 46 to 55 and finally beyond 55 years. In order to establish user profiles, the users were inquired about their amount of familiarity with iDTV, if they had already made use of e-commerce and if they would buy products over TV.

The dataset used for the test contains cell phones data like characteristics and prices, and it was get from a local store. The dataset contains information like cell phones dimensions, weight, display size, camera resolution, GPS and wi-fi functionalities, price and others. There are twenty records in the dataset, divided in ten attributes, five categorical and five continuous.

The proposed test was not oriented, which means, the user did not get instructions on how to perform the tasks in the test. The user got just information in which context the application will be used, its functionality and the set of keys to interact with an Ginga application.

We chose to conduct the test that way because in a real use scenario, viewers will not have any prior training to use the application. The test is made of five tasks, each one delimited by a time and with an additional time tolerance of one minute, except for the first task.

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5.1. Proposed tasks

The first task intends to identify if the users are able to start the application in a given time. We used two minutes as this time. No additional time was given since the application is no longer available to start once the TV commercial have ended. The second task consisted of two minutes for the user interact with the application at will. The intention here is to give the user a time to explore and get more used to the ways of interaction with the application. As task two is just a free time, it is not determined in section 5.2, but the impressions gathered from users in this task are mentioned in section 5.3.

The third task gives 4 minutes for the user to take a look at the offered products, using any interaction ways, choose one and add it to the "cart" for later purchase. The objective here is verify if the feedback given by the interface is enough to catch user's attention for the product added to cart.

In the fourth task, the user are supposed to be able to find the cell phone with the higher value for a continuous attribute, in this case, the price. This task wants to verify the way user are able to complete it, since configuring the size of items in the treemap will lead to the answer with only one interaction. The time for thgis task was also four minutes.

The fifth task is an extension of the previous one, but slightly more difficult since it combines two attributes one categorical and one continuous. In this task the user are asked to find the cell phone with higher price that has touchscreen display. Once the configurations made are reset for each task, this task required the configuration for the last one to be remade, justifying the time of 4 minutes for this task.

5.2. Results

Figure 5 shows the success and failure rates for each task. Even we choosing users who claim to use TVs at least daily, some of them show resistance to the way of interacting with the application. When asked about this resistance, users come up with the information that they use very few resources of the TV, most of them only use the channel and volume turn buttons. This factor was mostly noticed in users from higher ages. 26% of the users are from 46 to 55 age range, 11% from 36 to 45, the other ranges has 21% of the users each.

Figure 5: percentage of users that succeeded

and failed in each task.

In the first task, 21% of the users could not start the

application in the given time, from these 75% are in the 46 to 55 range and 25% in beyond 55 range. Among the

ones who started the application the longest time registered for this was 180 seconds and shortest time was 5 seconds. 75% from these 5 seconds users claim they do not have any previous knowledge/experience using iDTV, and none of these users were above

In the third task only 53% of the users were able to find, add and percept that one item was added to the cart, 32% of the user were not able to find and add an product to the cart at all.

63% of the users succeeded in finishing the task 4 in the given time. However, we notice that some of them did not realize any treemap configuration, the task was realized only navigating, observing on demand details and remembering the prices of already visited items.

Despite the fifth task is an extension of the previous one, 47% of the users were not able to succeed in it. 20% of the users who failed task 4 completed task 5 correctly. From the users who completed this task, only 10% completed it by configuring the treemap to display graphical information about both attributes analyzed. The other users completed the task by navigating, looking into on demand details and remembering the characteristics of visited items.

At the end of the test each participant was asked to fulfill an NASA-TLX assessment [15], in order to evaluate the test subjective workload, which an average value of 37,31.

5.3. Conclusions

We noticed that the captions were not used by most of participants, some of them do not even notice it. When asked about, some users report that it was not enough visible, while orders claimed to have noticed and did not understand the meaning of the words in the caption. We connect this fact to two factors: the use of words very close to IV, like "hierarchy", but not so common in other contexts and the decision to keep the captions under the visualization. We believe that the small size of the captions and the visual appeal of the treemap cooperate to "hide" the captions.

The major problem reported by the users was the navigation. Users do not see the treemap as a tree, but as a plain arrangement of rectangles, and so, most of them showed difficulty to use the hierarchical navigation.

Even after having successfully navigating inside and outside the treemap levels, some users apparently forgot that need and tried to go from one item in a group to other in another group only using the arrows. In this cases the instruction of use in the right side of the interface also does not seems to be enough to aid the user.

Again, the terms used for the instructions were not clear enough to user understand. Some users reported not being able to easily figure the keys to enter and leave an group, while others complained that hierarchical navigation only difficult the interaction.

During the test, most of users did not make use of the instructions or captions. In general, they used

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memory to keep track of the configurations made. Another point was they prefer to navigate through the visualization and check characteristics on details, instead of reconfigure the visualization.

The users expressed to like the treemap technique and the use of the grouping options, using this feature was identified as a key in the task 1. However, the lack o perception over the captions usually made users return to configurations to remember what was previously configured.

6. Final Considerations

Even with the environment limitations and the lack of prior training for the users we considered the test results as positive. It is important to highlight that most users had never saw an IV tool before and had little, some had none at all, experience with any kind interactive graphics.

In every task more than half of users succeeded in completing it in the given time, implying that the application can be successfully used as an mean of digital inclusion.

Another positive factor was that no user pointed the application performance was an issue, even in interaction that forced full treemap redrawing. Nevertheless an evaluation to determine until what amount of data (being in number of items or in number of attributes) the performance is acceptable, remains to be done.

The issues mostly pointed by users were the hierarchical navigation and the viewer support. The research now on might focus in develop an way to navigate more easily and not as costly for the user as plain navigation. The viewer support, as caption and usage instructions, are to be made more visible or explore other ways to call the user perception.

As a future work, we intent to have a similar group of users to perform similar tasks in a computer based information visualization tool. The idea is to compare both quantifiable and non-quantifiable, as users impression, between both environments (computer and TV). It will also serve to validate or not the premise if the iDTV, considering TV popularity in Brazil, is a better entrance point for digital inclusion.

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