Human-Computer Interaction and Presence in Virtual Reality

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Chapter 3 keyboard. Before the therapy session, the therapist can alter certain parameters of the VE. During the exposure session, the therapist can alter certain elements in the VE. We see several systems where the therapist can control the viewpoint of the patient and several systems where the patient is in control of his or her viewpoint. 34 Name system Display Viewpoint Input devices Controls Hanyang University Virtually Better Different Display than patient Different Display than patient VRHealth Different Display than patient Previ Different Display than patient DriVR Different Display than patient VRT-2002 Different Display than patient CYBERmed Different Display than patient Same viewpoint as patient Same viewpoint as patient Same viewpoint as patient Same viewpoint as patient Same viewpoint as patient Same viewpoint as patient Same viewpoint as patient Keyboard Joystick Tracked device Elements Pre-VE modifications Keyboard Elements Viewpoint Pre-VE modifications Keyboard None Keyboard Elements Viewpoint Pre-VE Keyboard Joystick Tracked device WIMP (pre- VE) Keyboard Joystick Tracked device WIMP (pre- VE) ? ? modifications Pre-VE modifications Elements Viewpoint Pre-VE modifications Table 3.3: User interface for the therapist, with type of display, viewpoint displayed, types of input devices and type of control the therapist has. 3.5.2 Virtual Reality testbed To investigate the human-computer interaction in current VRET-systems and to evaluate modifications to the user interfaces a testbed was created (Schuemie & van der Mast, 2001). The system was designed to meet the following requirements: 1. The system had to be easy to modify. It should be possible to test various types of interfaces for both therapist and patient. 2. The system must have the potential for effective therapy. Unfortunately, very little is yet known about the specific requirements needed for evoking phobic responses in VR. We
Analysis have assumed that stereoscopy would be important for acrophobia, since this greatly enhances the perception of depth. 3. The system should not be too expensive. Since the system is intended for use by therapists, the system should be affordable for institutions with a small budget The choice was made for a PCbased system with off-the-shelve components. The display was a Visette Pro stereoscopic HMD with a field of view of 70 degrees diagonal. The position of the HMD was tracked using the Ascension Flock of Birds, a six DoF tracker. The two images, respectively for the left and right eye, were generated using two Intergraph Intense3D Pro 2200s cards with 16 megabytes of texture memory each. These cards were chosen because the output of these cards can be synchronized using a so-called GenLock, a necessary requirement for most TCP/IP Delphi WorldUp OpenGL Windows NT Delphi WorldUp Direct 3D Windows 98 Patient’s computer Therapist’s computer Intense 3D Pro GenLock Intense 3D Pro keyboard, mouse joystick 3D card Flock of Birds Figure 3.8: Overview of the testbed configuration used for the VRET. HMDs. During the years of the research described in this dissertation, these cards were replaced with a single, much faster graphics card: the 3D-Labs Oxygen GVX420. A second computer was used to display the user interface for the therapist, and the two computers communicated over a standard Ethernet network using the TCP/IP protocol. This made it possible to connect the two computers over great distances, but this was never used in our experiments. The VR software package used was WorldUp R4 by Sense8. This high level toolkit made it possible to develop new VEs within several days. Furthermore, it has support for a wide variety of input and output devices. For extended functionality, such as two-dimensional graphical user interfaces, network communication, database access and complicated computations, Borland Delphi 5 was used to create Dynamic Link Libraries (DLLs) which were called from WorldUp. An overview of the system is presented in figure 3.8. 3.5.3 Case: acrophobia treatment To investigate the human-computer interaction in VRET, therapists of the University of Amsterdam used the system to treat patients clinically diagnosed as having fear of heights. These treatments were also part of two investigations in comparing VRET to exposure in vivo (Emmelkamp et al., 2002; Krijn et al., in preparation). The choice for acrophobia was based on the fact that this is one of the less complicated phobias. Subjects The therapists involved were four master students and a PhD student in clinical psychology, who already had some experience in phobia treatment. Patients were individuals suffering from acrophobia as their main complaint, who referred themselves for treatment after 35
Page 1: Human-Computer Interaction and Pres
Page 4 and 5: Dit proefschrift is goedgekeurd doo
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Page 11 and 12: 1 Introduction Human Computer Inter
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Page 27 and 28: 3 Analysis As stated in the previou
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Page 31 and 32: Analysis works (Benyon & Imaz, 1999
Page 33 and 34: Analysis actors. Besides this, Cont
Page 35 and 36: Analysis 1979; Habermas, 1981; Diet
Page 37 and 38: Analysis influence each other. To b
Page 39 and 40: Analysis 3.3.3 State information No
Page 41 and 42: Analysis Unfortunately, this will m
Page 43: Analysis Name system URL website Ph
Page 47 and 48: Analysis several modalities of comm
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Page 55 and 56: Goals Procedures Sound T.Controls T
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Page 59 and 60: Goals Procedures Sound HMD screens
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Page 65 and 66: 4 Presence The research described i
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Chapter 5 a base transmitter that g
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Chapter 5 3. Gaze-directed: This te
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Chapter 5 content of labels distrib
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Chapter 5 Measures Prior to the exp
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Chapter 5 Unstandardized Coefficien
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Chapter 5 phobia that often involve
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Chapter 5 subjects were all diagnos
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Chapter 5 VE does show a significan
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Chapter 5 possible explanation coul
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Chapter 5 Large drop Large drop A2
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Chapter 5 5.5.2 Results Subjects Mi
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Chapter 5 the SUD scores in the dif
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Chapter 5 The third experiment clea
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6 Therapist's user interface The UI
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6.2.1 SUDs recording During therapy
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Therapist’s user interface Figure
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Therapist’s user interface The st
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Therapist’s user interface The 2D
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Therapist’s user interface Heartr
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Therapist’s user interface • To
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Therapist’s user interface elemen
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7 Conclusions In this dissertation
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7.1.2 Determining the patient's fea
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Conclusions patient control allowed
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Conclusions Guideline 5: A tool for
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References Alcaniz , M. Banos , R.M
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References Dietz, J.L.G., Widdersho
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References Hodges, L., Rothbaum, B.
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References Lombard, M., Ditton, T.(
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References Reeves, B., Nass, C. (19
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Slater, M. (1999). Measuring Presen
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References van Welie, M. (2001) Tas
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UED User Environment Design VE Virt
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Appendix A Complaints and wishes 'F
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Appendix A A.4 Experiment 3 Compute
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Appendix A 3. Were you able to see
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Appendix A 28. 'If you had to choos
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Appendix B Element: Instruct patien
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Appendix B Element: Inform patient
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Appendix B Element: Listen for resp
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De TA methode is getoetst door deze
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Curriculum vitae Martijn Schuemie w
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2000-1 Frank Niessink (VU) Perspect
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2002-09 Willem-Jan van den Heuvel(K
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