1. Chapter 5. Navigation and Interaction in Real and Virtual Environments
Virtual Environments
Engineering Psychology and Human Performance
Seo-Jung Ko, industrial Engineering , Hanyang University.

2. contents
1. Virtual Environments
Definitions
six features of a virtual environment
augmented reality
2. Benefits of Virtual Environments
the ego-centered frame of reference for many guidance tasks
Usefulness for training
On-line comprehension
3. Problems for Virtual Environments
expensive
Computationally intensive and lag problems
Potential biases or distortions
the need for a world-centered frame
Motion sickness
4. Summary
Seo-Jung Ko, industrial Engineering , Hanyang University.

3. Virtual Environments
Definitions
a virtual environment(VE)
 can be defined as the multisensory experience of a location or set of locations th
rough artificial, electronic means.
 environment can be interactively experienced and manipulated by the observer.
VR(Virtual Reality) (x), VE(Virtual Environment) (o)
presence실재감 (≒immersion몰입)
 defined as the extent to which human participants in a virtual environment allow
themselves to be convinced that they are somewhere other than where they phy
sically are.
 immersion (몰입)
재미있는 영화를 볼 때, 완전히 영화에 몰입하여 극장에 있다는 것을 잊어버리고 영화
속의 어떤 환경에 푹 빠져있다고 느끼는 것과 유사.
Seo-Jung Ko, industrial Engineering , Hanyang University.

4. Virtual Environments
six features of a virtual environment
1. Three-dimensional viewing
Since space is three dimensional, a display representation that preserves that characteris
tic is more realistic than a two-dimensional representation.
2. Dynamic
We experience time as continuous. Hence, a virtual display should allow the user to view
(and control) events dynamically in real time.
3. Closed-loop interaction
The virtual world should also respond quickly to control inputs so that there is little lag 렉.
4. Ego-centered frame of reference
An Ego-centered frame of reference presents the image of the world from the FFOV
An Ego-centered frame
Seo-Jung Ko, industrial Engineering , Hanyang University.

5. Virtual Environments
six features of a virtual environment
5. Multimodal interaction
Therefore, virtual environments may also include auditory feedback using 3-D localized
sound techniques, and proprioceptive고유감각, kinesthetic운동, force힘, and tactile촉각
feedback using a dataglove, 3-D mouse, or joystick.
6. Head-mounted display and tracking
Many VE systems incorporate a head-mounted display(HMD) and motion sensors.
Seo-Jung Ko, industrial Engineering , Hanyang University.

6. Virtual Environments
augmented reality.
• virtual objects elements are added to real-world scenes.
• typically, they require the use of a see-through head-mounted display that shows
the virtual objects overlaid on the real-world.
Seo-Jung Ko, industrial Engineering , Hanyang University.

7. contents
1. Virtual Environments
Definitions
six features of a virtual environment
augmented reality
2. Benefits of Virtual Environments
the ego-centered frame of reference for many guidance tasks
Usefulness for training
On-line comprehension
3. Problems for Virtual Environments
expensive
Computationally intensive and lag problems
Potential biases or distortions
the need for a world-centered frame
Motion sickness
4. Summary
Seo-Jung Ko, industrial Engineering , Hanyang University.

8. Benefits of Virtual Environmental
Three fundamental benefits
1. The potential advantage of the ego-centered frame of reference
for many guidance tasks.
2. Usefulness for training
because it is often safer or less expensive than training in the real environment
ex) 비행기 조종 연습, 마취 주사 연습.
ex) 비행 조종 연습시 연료 비, 인건비 등을 아낄 수 있음.
3. On-line comprehension.
to assist the user in gaining insight about the structure of an environment.
건축설계사는 HMD를 착용하고 3차원의 가상적 빌딩을 걸어 다녀 봄으로써
방의 배열에 대한 통찰을 얻을 수 있을 것이다.
Seo-Jung Ko, industrial Engineering , Hanyang University.

9. contents
1. Virtual Environments
Definitions
six features of a virtual environment
augmented reality
2. Benefits of Virtual Environments
the ego-centered frame of reference for many guidance tasks
Usefulness for training
On-line comprehension
3. Problems for Virtual Environments
expensive
Computationally intensive and lag problems
Potential biases or distortions
the need for a world-centered frame
Motion sickness
4. Summary
Seo-Jung Ko, industrial Engineering , Hanyang University.

10. Problems for Virtual Environments
1. The technology tends to be expensive.
2. Rendering 3-D graphics in real time실시간 is computationally intensive and can lead to
serious lag problems, making interactivity impossible. And lag reduces presence.
Lag can be reduced by reducing the number of virtual environment elements.
몇몇 연구자들은 다른 것은 몰라도 motion 만큼은 렉 없이 사실적으로 묘사되어야 한다고 주장한다.
3. Potential biases or distortions occur in virtual environments.
 2-D-3-D effect
Make a level plane appear to be an uphill surface.
 Virtual space effect
Biases in perceived location of objects resulting from the amount of magnification
of view on the virtual environment. That is, targets are perceived as higher than
they actually are.
However, stereo disparity improves estimates of elevation.
 limited field of view
limited field of view can lead to and underestimation of distances in depth.
However, object-centered, monocular cues (aerial perspective, occlusion)
can be computationally cheap and can improve depth perception in virtual spaces.
Seo-Jung Ko, industrial Engineering , Hanyang University.

11. Problems for Virtual Environments
4. if virtual environments is large, then the user can get lost or disoriented 방향을잃다 ,
leading to the need for a world-centered frame of reference of the virtual environment.
we see a clear advantage for adding a world-centered frame of reference to the
immersed view when navigation virtual space.
5. Motion sickness (sometimes referred to as cybersickness in VE)
Symptoms such as well nausea구역질,dizziness어지러움,and disorientation방향상실.
 Cybersickness is reduced if there is 1:1 relationship between the angle of head motion and t
he change in display angle
 And if the direction of the observer’s gaze corresponds to the direction of motion.
Seo-Jung Ko, industrial Engineering , Hanyang University.

12. contents
1. Virtual Environments
2. Benefits of Virtual Environments
3. Problems for Virtual Environments
4. Summary
Virtual environments offer an innovative technological solution to
problems for training, on-line performance, and on-line comprehension.
However, the designer must avoid or minimize limitations of the technolo
gy (cost, computational demands, perceptual biases, disorientation, cybersickness)
to make virtual environments maximally effective.
Seo-Jung Ko, industrial Engineering , Hanyang University.