Finding information again using an individual’s web history

In a lifetime, an “average” person will visit approximately a million webpages. Sometimes a person finds they want to return to a given page at some future date but, having no recollection of where it was (URL, host, etc.) and so has to look for it again from scratch. This paper assesses how a person’s memory could be assisted by the presentation of a “map” of their web browsing activity. Three map organisation approaches were investigated: (i) time-based, (ii) place-based, and (iii) topic-based. Time-based organisation is the least suitable, because the temporal specificity of human memory is generally poor. Place-based approaches lack scalability, and are not helped by the fact that there is little repetition in the paths a person follows between places. Topic-based organisation is more promising, with topics derived from both the web content that is accessed and the search queries that are executed, which provide snapshots into a person’s cognitive processes by explicitly capturing the terminology of “what” they were looking for at that moment in time. In terms of presentation, a map that combines aspects of network connectivity with a space filling approach is likely to be most effective

Using string-matching to analyze hypertext navigation

A method of using string-matching to analyze hypertext navigation was developed, and evaluated using two weeks of website logfile data. The method is divided into phases that use: (i) exact string-matching to calculate subsequences of links that were repeated in different navigation sessions (common trails through the website), and then (ii) inexact matching to find other similar sessions (a community of users with a similar interest). The evaluation showed how subsequences could be used to understand the information pathways users chose to follow within a website, and that exact and inexact matching provided complementary ways of identifying information that may have been of interest to a whole community of users, but which was only found by a minority. This illustrates how string-matching could be used to improve the structure of hypertext collections

Navigation: am I really lost or virtually there?

Data is presented from virtual environment (VE) navigation studies that used building- and chessboard-type layouts. Participants learned by repeated navigation, spending several hours in each environment. While some participants quickly learned to navigate efficiently, others remained almost totally disoriented. In the virtual buildings this disorientation was illustrated by mean direction estimate errors of approximately 90°, and in the chessboard VEs disorientation was highlighted by the large number of rooms that some participants visited. Part of the cause of disorientation, and generally slow spatial learning, lies in the difficulty participants had learning the paths they had followed through the VEs

Generating trails automatically, to aid navigation when you revisit an environment

A new method for generating trails from a person’s movement through a virtual environment (VE) is described. The method is entirely automatic (no user input is needed), and uses string-matching to identify similar sequences of movement and derive the person’s primary trail. The method was evaluated in a virtual building, and generated trails that substantially reduced the distance participants traveled when they searched for target objects in the building 5-8 weeks after a set of familiarization sessions. Only a modest amount of data (typically five traversals of the building) was required to generate trails that were both effective and stable, and the method was not affected by the order in which objects were visited. The trail generation method models an environment as a graph and, therefore, may be applied to aiding navigation in the real world and information spaces, as well as VEs

Movement around real and virtual cluttered environments

Two experiments investigated participants’ ability to search for targets in a cluttered small-scale space. The first experiment was conducted in the real world with two field of view conditions (full vs. restricted), and participants found the task trivial to perform in both. The second experiment used the same search task but was conducted in a desktop virtual environment (VE), and investigated two movement interfaces and two visual scene conditions. Participants restricted to forward only movement performed the search task quicker and more efficiently (visiting fewer targets) than those who used an interface that allowed more flexible movement (forward, backward, left, right, and diagonal). Also, participants using a high fidelity visual scene performed the task significantly quicker and more efficiently than those who used a low fidelity scene. The performance differences between all the conditions decreased with practice, but the performance of the best VE group approached that of the real-world participants. These results indicate the importance of using high fidelity scenes in VEs, and suggest that the use of a simple control system is sufficient for maintaining ones spatial orientation during searching

Changes in navigational behaviour produced by a wide field of view and a high fidelity visual scene

The difficulties people frequently have navigating in virtual environments (VEs) are well known. Usually these difficulties are quantified in terms of performance (e.g., time taken or number of errors made in following a path), with these data used to compare navigation in VEs to equivalent real-world settings. However, an important cause of any performance differences is changes in people’s navigational behaviour. This paper reports a study that investigated the effect of visual scene fidelity and field of view (FOV) on participants’ behaviour in a navigational search task, to help identify the thresholds of fidelity that are required for efficient VE navigation. With a wide FOV (144 degrees), participants spent significantly larger proportion of their time travelling through the VE, whereas participants who used a normal FOV (48 degrees) spent significantly longer standing in one place planning where to travel. Also, participants who used a wide FOV and a high fidelity scene came significantly closer to conducting the search "perfectly" (visiting each place once). In an earlier real-world study, participants completed 93% of their searches perfectly and planned where to travel while they moved. Thus, navigating a high fidelity VE with a wide FOV increased the similarity between VE and real-world navigational behaviour, which has important implications for both VE design and understanding human navigation. Detailed analysis of the errors that participants made during their non-perfect searches highlighted a dramatic difference between the two FOVs. With a narrow FOV participants often travelled right past a target without it appearing on the display, whereas with the wide FOV targets that were displayed towards the sides of participants overall FOV were often not searched, indicating a problem with the demands made by such a wide FOV display on human visual attention

For efficient navigational search, humans require full physical movement but not a rich visual scene

During navigation, humans combine visual information from their surroundings with body-based information from the translational and rotational components of movement. Theories of navigation focus on the role of visual and rotational body-based information, even though experimental evidence shows they are not sufficient for complex spatial tasks. To investigate the contribution of all three sources of information, we asked participants to search a computer generated “virtual” room for targets. Participants were provided with either only visual information, or visual supplemented with body-based information for all movement (walk group) or rotational movement (rotate group). The walk group performed the task with near-perfect efficiency, irrespective of whether a rich or impoverished visual scene was provided. The visual-only and rotate groups were significantly less efficient, and frequently searched parts of the room at least twice. This suggests full physical movement plays a critical role in navigational search, but only moderate visual detail is required

A new method for interacting with multi-window applications on large, high resolution displays

Physically large display walls can now be constructed using off-the-shelf computer hardware. The high resolution of these displays (e.g., 50 million pixels) means that a large quantity of data can be presented to users, so the displays are well suited to visualization applications. However, current methods of interacting with display walls are somewhat time consuming. We have analyzed how users solve real visualization problems using three desktop applications (XmdvTool, Iris Explorer and Arc View), and used a new taxonomy to classify users’ actions and illustrate the deficiencies of current display wall interaction methods. Following this we designed a novel methodfor interacting with display walls, which aims to let users interact as quickly as when a visualization application is used on a desktop system. Informal feedback gathered from our working prototype shows that interaction is both fast and fluid

Movement around real and virtual cluttered environments

Two experiments investigated participants’ ability to search for targets in a cluttered small-scale space. The first experiment was conducted in the real world with two field of view conditions (full vs. restricted), and participants found the task trivial to perform in both. The second experiment used the same search task but was conducted in a desktop virtual environment (VE), and investigated two movement interfaces and two visual scene conditions. Participants restricted to forward only movement performed the search task quicker and more efficiently (visiting fewer targets) than those who used an interface that allowed more flexible movement (forward, backward, left, right, and diagonal). Also, participants using a high fidelity visual scene performed the task significantly quicker and more efficiently than those who used a low fidelity scene. The performance differences between all the conditions decreased with practice, but the performance of the best VE group approached that of the real-world participants. These results indicate the importance of using high fidelity scenes in VEs, and suggest that the use of a simple control system is sufficient for maintaining ones spatial orientation during searching

Using mobile group dynamics and virtual time to improve teamwork in large-scale collaborative virtual environments

Mobile group dynamics (MGDs) assist synchronous working in collaborative virtual environments (CVEs), and virtual time (VT) extends the benefits to asynchronous working. The present paper describes the implementation of MGDs (teleporting, awareness and multiple views) and VT (the utterances of 23 previous users were embedded in a CVE as conversation tags), and their evaluation using an urban planning task. Compared with previous research using the same scenario, the new MGD techniques produced substantial increases in the amount that, and distance over which, participants communicated. With VT participants chose to listen to a quarter of the conversations of their predecessors while performing the task. The embedded VT conversations led to a reduction in the rate at which participants traveled around, but an increase in live communication that took place. Taken together, the studies show how CVE interfaces can be improved for synchronous and asynchronous collaborations, and highlight possibilities for future research