Concepción de la lectura literaria en la infancia 50

Based on the discussion of supporting Exploratory Browsing with media collection (cf. Section 1.2.3 in Chapter 1), we believe that such interfaces should follow several fundamental characteristics. As a specific target is involved in Search Browsing, keyword-based search should be supported. For collections initially lacking meaningful names, such as photos, the system should allow a structured navigation, which helps the user locating the target quickly along a clear structure. Search for one specific item is not common with media collections, and people tend to spend more time on browsing. They may start with a relevant neighborhood and invest effort on comparing and understanding the underlying relations between relevant items, which helps users to find acceptable candidates. Therefore, allowing definition of areas of interest is necessary. Since people‟s mental model of their collections often goes beyond a linear structure, the system should provide additional nonlinear representations of the collection. Moreover, these representations should be adjustable, in order to follow people‟s often changing intentions. Without specific goals, people may easily get sidetracked by unexpected but interesting findings. To help them recovering from serendipity, backtracking should be allowed.

Based on these general interface characteristics, we analyzed the effectiveness of some existing work to support Exploratory Browsing. Most of the photo applications shown in Figure 2.11 support structured navigation, mainly based on time or folder structure. Regarding the nonlinear representation, several systems provide a map-based visualization based on photos‟ geographic information or content similarity.

Linear structures for music collections, such as artist- and album-views in iTunes, can be easily achieved. In Figure 2.12, one can observe that researchers are seeking for novel representations for music collections, such as a map view based on additional criteria of similarity, tempo or mood. Torrens et al. (2004) proposed three novel concepts to visualize a music collection: a disc, a rectangle and a treemap. In Artist map the user can decide on the

two criteria used to display songs on a 2D map, but has no influence on the layout. Moreover, most of the applications use similarity as the only criterion for organization and browsing.

Application Characteristic

Event-based Geographic Tabletop Others

Time Quilt FX PAL Photo Explorer Photo Field WW MX PDH Photo helix iPhoto Media GLOW Search Browsing Structured navigation √ √ √ √ √ √ √ Exploratory Browsing Nonlinear representation √ √ √ √ √ Multiple representations √ √ √ √

Defining areas of interest √

Steerable representation √ Backtracking

Figure 2.11: An analysis of some photo applications based on the initial catalogue of general interfaces characteristics to support Exploratory Browsing.

Application Characteristic

Similarity-based Playlist generation Others

Islands of Music Music Rainbow Music- ream E-Mu jukebox Artist map iTunes Torrens Music Land MUSIC table Search Browsing Structured navigation √ Exploratory Browsing Nonlinear representation √ √ √ √ √ √ √ Multiple representations √

Defining areas of interest √

Steerable representation √

Backtracking √

Figure 2.12: An analysis of some music applications based on the initial catalogue of general interfaces characteristics to support Exploratory Browsing.

In most of the systems listed in Figure 2.11 and 2.12, the user cannot actively control the representation nor define areas of interest. The three exceptions are FXPAL, MediaGLOW and E-Mu jukebox. In FXPAL the user can refine the automatically generated event structure. MediaGLOW allows defining a time interval of interest. E-Mu jukebox allows defining music preferences by drag-and-drop the relevant parameters in a graph, and the matching songs will be dynamically updated in a list. To facilitate recovery from serendipity, Musicream is the only system to allow recalling a past activity with its “time machine” facility. It records all operations performed by the user as well as all screen changes. The user can switch back to a

2.3 Discussion 35

previous status with a slider, or search for past screens where a specific song or songs similar to an example song were listened to.

In summary, structured navigation can be easily achieved based on the original reliable metadata, such as time for photos, and artist and album for music. Researchers have realized the usefulness of nonlinear exploration, but mainly achieve map-based representations based on additional criteria associated with media intrinsic attributes, such as similarity, tempo and mood. This type of additional information enables more browsing possibilities, but novel representations and more elaborate user interactions need further investigation. Other functionalities to facilitate Exploratory Browsing, such as defining areas of interests, steerable representation and backtracking facility, are poorly support in these systems.

Although existing studies on user behavior have already highlighted the prevalence of exploratory behavior around media collections, applications efficiently supporting Exploratory Browsing are still in absence. The simple and fixed browsing structures offered in current interfaces cannot efficiently support users‟ exploratory and often unstructured browsing activities. Moreover, fluid and elaborate user interactions are poorly supported. The full range of browsing activities and their underlying relations have not been thoroughly studied. All these facts motivate us to explore interface design to enhance the browsing experience with media collections. In this thesis we systematically examine the model of Exploratory Browsing

in two main usage contexts: with personal collections and in online communities. The insights derived in the development and evaluation of our prototypes enable reflections and refinement of the initial model of Exploratory Browsing. Next part presents our exploration to support the

Part II

Supporting Exploratory Browsing in

Personal Media Collections

39

The first part of this thesis analyzes the related work in the field of interface design for media collections, which embodies the necessity to design interfaces to support Exploratory Browsing in media collections. This part presents our exploration with personal media collections.

Chapter 3 discusses our initial work based on similarity and presents two similarity-based interfaces PhotoSim and MusicSim for photos and music respectively. The results of the preliminary tests revealed that similarity is appreciated as a secondary criterion for organization and browsing and should be offered on demand. We suggested enhancing the performance of similarity by a close coordination with reliable criteria and by introducing more elaborate user interactions.

To improve the browsing efficiency and flexibility, in Chapter 4 we combined similarity with reliable criteria and additional information, specifically User-Generated Data (UGD). UGD used in this chapter is generated by single users, such as item popularity extracted from the user‟s consumption records and tags contributed by the user. We developed two prototypes

CloudMonster and PhotoMagnets to enhance the browsing flexibility with personal photo and music collections respectively, in which elaborate interactions are proposed to enable more active user control.

Chapter 5 discusses the insights gathered during the development and evaluation of these four prototypes. We proposed several general considerations for designing browsing interfaces for media collections. We also discussed the different evaluations approaches of these prototypes. The analysis and observation of the users‟ behavior enabled a refinement of the initial model of Exploratory Browsing by uncovering the transitional relations between the prominent General Purpose Browsing and the other two browsing activities.

The exploration in this part motivated an investigation in the other usage context in online communities, which is discussed in Part III.

3

Similarity-based Browsing

As discussed in Chapter 1, current browsing interfaces for media collections mostly offer linear scan corresponding to the underlying technical concepts (folder, events, etc.) or the metaphors borrowed from the analogue counterparts (e.g., stacks, film rolls). However, people‟s mental model of their media collections often goes beyond this linear structure. For example, we might look for a nice photo of our kids without caring where and when it was taken, or compile a happy and lighthearted playlist for a birthday party. This kind of similarity-driven exploration is poorly supported in today‟s interfaces for media collections. We started our initial exploration based on similarity. We employed similarity as the main criterion and developed

PhotoSim (Chen and Butz, 2008) and MusicSim (Chen and Butz, 2009) to support similarity-based browsing with personal photo and music collections respectively. The results of the preliminary tests revealed that similarity is generally appreciated but more suitable as an additional criterion offered on demand.