Way-Finding Study Proposal

(First of Two or Three: to be followed with a collaborative study, perhaps another with more explicit landmarks)

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Purposes
Phase I: Driver Training
Phase II: Guided Tours
The 4 Conditions
Phase III: Independent Travel
Expectations
Data Collected
Discussion of Issues
Time Outline
Implementation Tasks


PURPOSES:


PHASES:

I - Driver Training

This first phase will allow the subjects to gain experience with the flying interface. The purpose of this phase is to ensure that subjects are competent in the FMVR environment before starting the later tasks. Interesting results may be obtained from this phase by itself. It will consist of 3 sections: In-class, Practice, and Examination.

1. The In-Class Section

There will be a brief introduction to the system. This will explain the individual widgets of the flying interface, how to steer (adjusting your trajectory), and the related concept of how to accelerate (adjusting your velocity). This will be a scripted introduction, to be delivered either verbally or on paper.

2. The Practice Section

The subjects will then be provided a fixed amount of time to become familiar with the flying interface. They will be placed in an environment which encourages the exploration of all degrees of movement, such as a drastically different landscape from the one to be used in later phases (different in character, colour, size, or other), or a 3-dimensional object to examine. Suggested tasks will be provided (eg. view the object from directly above), but the activities of the practice section will not be monitored or analyzed in any detail.

3. The Examination Section

The subjects will proceed to the Driver's Test. They will be given a task to complete, in a landscape that is drastically different from the one to be used in later phases. For example, they may be given a flat landscape, with objects dispersed along a particular path through the terrain. Their task might be to steer to the first object, and drive through it. Upon successful completion, the next object in the path appears, at a different location and height, and so on to the end of the path. This will show their ability to steer themselves through the virtual environment. Measures that can be taken include: Upon successful completion of the examination in a reasonable amount of time and along a reasonably efficient path, the subjects will advance to the final two sections. If the subjects fail to achieve reasonable success in this section, we can do one of two things:
  1. End their involvement with the experiment
  2. Permit a second chance, starting them afresh from the Driver Training phase.

II - Guided Tours

Phase II of the experiment will take the subjects to the experiment landscape for the first time. The purpose of this phase is to have them gain exposure to a given virtual environment, for them to internalize it. This phase will also introduce the controlled variable, as each subject is assigned to one of four conditions.

Common to all subjects, regardless of condition, will be a landscape with several pre-defined Departure and Arrival stations. The subjects will be guided along a set of paths through the terrain, each one from a specific Departure station, and to a particular Arrival station. For example, there may be 5 Departure stations (Red, Green, Blue, Grey, and Yellow) and 5 Arrival stations (same colour set, but light in colour, whereas the Departure stations will be dark). The subjects will know how many of each station there are, from a scripted scenario describing this phase. They will also know which stations they are traveling between, either from the visible representation on the screen, or from a text message of some sort. The set of paths will include intersections and some commonalities, and the subjects will learn the paths from observing the surrounding landscape (implicit landmarks) and the heading information (where provided). They will be guided by a "pilot car" which travels in front of them along the path. Perhaps each path on the guided tour should be repeated. (Q: Should the order of paths remain constant between subjects? or be randomly presented?)

Subjects will be randomly assigned to one of four conditions for this phase:

  1. Back-Seat Passenger
    In this condition, the subject is "towed" along at a fixed distance behind the pilot car. As in the back of a chauffeured limousine, the passenger may passively watch the terrain go by, without steering and without the benefit of the heading clues provided by the flying widgets.
  2. Front-Seat Passenger
    As in the previous condition, the subject is passive, doing no steering. They are towed at the fixed distance behind the pilot car. They may observe the passing scenery, but will also have the flying interface widgets as additional heading information. This is akin to taking the tour in the front seat, where you may observe the terrain and what the driver is doing to travel through it.
  3. Small Autonomy
    This condition requires active following on the part of the subjects. The pilot car will travel along its pre-determined path, and the subjects must guide their vehicle behind it. They will have total motion control within a certain but small volume behind the pilot car. If they travel outside this volume, they will essentially be getting off the path they are to follow. When this occurs, we will apply sinusoidal clipping to the component of their velocity taking them off the approved path, down to zero at a pre-determined maximum deviation. This condition can generate data, regarding how well the subjects remain in the "ideal" zone behind the pilot car, and how often and severely velocity clipping must be applied.
    This clipping is designed to keep subjects from wandering too far left or right of the path they are to learn, or from getting too high above the surface, or from sinking below the surface. It can also apply to the distance from the pilot car; as the subjects get too close and risk overtaking the pilot car, the clipping will gradually reduce their velocity in this direction until it matches the leader at some minimum distance. Likewise as they fall too far behind the pilot car, either their speed can be adjusted up to match it, or (preferable)its speed can be gradually slowed to match the subjects.
  4. Large Autonomy
    This condition is the same as number 3, except the volume in which the subject has full autonomy is larger. It too can generate data of how well subjects followed in the "ideal" zone.


III - Independent Travel

In the final phase, we will be testing the subjects for their knowledge of the paths they have traveled, and their understanding of the entire environment. This will be accomplished by giving them two sets of tasks: (1) Travel along a selection of the paths that they were shown, known paths between Departure and Arrival stations; and (2) Find their way between a Departure-station:Arrival-station pair between which they have NOT been shown any paths. They will have multiple experiences with both stations in each case, but will have never been guided from one to the other.

Expectations are that the extra noise of condition 2 vs condition 1 will result in a greater ability to navigate through the terrain, but may detract slightly from understanding and internalizing it. It is also anticipated that the smaller autonomy will produce a greater understanding of the terrain. Conditions 3 and 4 are expected to produce better traversal times, as the subjects will have experience in steering along the paths.

How well the space is internalized will be assessed by teaching a set of paths through the space (by a follow-the-leader technique) to the subjects, and having them navigate the paths solo later. A close match between the intended and traveled paths will suggest an internalization of the data space.

This raises the issue of how to differentiate between the following:

Familiarity with the interface will be judged based on a period of experimentation, followed by some trials to navigate to specific points. This is related to some work done by Ware and Fleet, in which user familiarity with aspects of the FledermausVR interface were judged by having them navigate up to and inside boxes in the terrain, to identify an enclosed letter. See the Driver Training phase for more.

Familiarity with the paths will be evaluated by having the subjects navigate along a path that was shown to them in the training phase. Successfully navigating such a path would indicate a potential understanding of the data space, and a definite understanding of the paths.

Familiarity with the space, separate from the paths, can be tested by having the subjects navigate between start and end points with which they are already familiar, but for which they have never been shown a path.

The following data will be collected during each task trial:


DISCUSSION:

I would welcome any additions, changes, comments and feedback on the above. There are some outstanding issues to be discussed or decided, which this section indicates. They include:

An estimated outline of the test session would resemble:

Minutes	Activity
====================
 5	Driver Training: In-Class (introduction to the system)
10	Driver Training: Practice
 5	Driver Training: Examination (benchmark of competency in interface)
 5	-- break (and assess results)
15	Guided Tour: following pilot car in one of 4 conditions
 5	-- break
10	Independent Travel: subject follows known paths in random order
 5	-- break
20	Independent Travel: subject way-finds (unknown paths, known points)
total time: 1 hour 20 minutes (assume 0.5 minute per known path, makes 15-20 paths; assume 1.0 minute for unknown paths, makes 15-20 paths).


IMPLEMENTATION TASKS

This study will require several changes to the Fledermaus system. Please advise if any are left off the list. At a first glance, these will include the following tasks to be done, as implementation changes or data preparation:


Prepared by: Steven Page, spage@cs.ubc.ca. Last updated: 18 Dec 1997.