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Doron Friedman
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Journal Articles
Publisher: Journals Gateway
Presence: Teleoperators and Virtual Environments (2014) 23 (3): iv–vi.
Published: 01 October 2014
Journal Articles
Publisher: Journals Gateway
Presence: Teleoperators and Virtual Environments (2014) 23 (3): 229–241.
Published: 01 October 2014
Abstract
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We present a robotic embodiment experiment based on real-time functional magnetic resonance imaging (rt-fMRI). In this study, fMRI is used as an input device to identify a subject's intentions and convert them into actions performed by a humanoid robot. The process, based on motor imagery, has allowed four subjects located in Israel to control a HOAP3 humanoid robot in France, in a relatively natural manner, experiencing the whole experiment through the eyes of the robot. Motor imagery or movement of the left hand, the right hand, or the legs were used to control the robotic motions of left, right, or walk forward, respectively.
Includes: Multimedia, Supplementary data
Journal Articles
Publisher: Journals Gateway
Presence: Teleoperators and Virtual Environments (2010) 19 (4): 291–301.
Published: 01 August 2010
Abstract
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This paper introduces the concept and discusses the implications of immersive journalism, which is the production of news in a form in which people can gain first-person experiences of the events or situation described in news stories. The fundamental idea of immersive journalism is to allow the participant, typically represented as a digital avatar, to actually enter a virtually recreated scenario representing the news story. The sense of presence obtained through an immersive system (whether a Cave or head-tracked head-mounted displays [HMD] and online virtual worlds, such as video games and online virtual worlds) affords the participant unprecedented access to the sights and sounds, and possibly feelings and emotions, that accompany the news. This paper surveys current approaches to immersive journalism and the theoretical background supporting claims regarding avatar experience in immersive systems. We also provide a specific demonstration: giving participants the experience of being in an interrogation room in an offshore prison. By both describing current approaches and demonstrating an immersive journalism experience, we open a new avenue for research into how presence can be utilized in the field of news and nonfiction.
Journal Articles
Publisher: Journals Gateway
Presence: Teleoperators and Virtual Environments (2009) 18 (4): 286–293.
Published: 01 August 2009
Abstract
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One of the main promises of collaborative virtual environments (CVEs) is that they would decrease the need for travel and face-to-face meetings. In this study we aim at comparing the dynamics and content of group discussions in desktop virtual environments with physical-world discussions. We have conducted an experiment in which four groups of 7–12 participants each carried out a political discussion on the same topic; specifically, global warming. Two groups conducted the experiment in a face-to-face setting and two other groups conducted a similar discussion inside the virtual world SecondLife ( http://www.secondlife.com ). Virtual-world discussions were found to include shorter sentences on average, have a smaller number of themes discussed, discuss a smaller number of themes in depth, and require a longer time for discussion threads to form. In this paper we provide a quantitative analysis of the similarities and differences between virtual-world and physical-world discussions.
Journal Articles
Publisher: Journals Gateway
Presence: Teleoperators and Virtual Environments (2008) 17 (3): 293–309.
Published: 01 June 2008
Abstract
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This paper presents qualitative findings from an experiment designed to investigate breaks in presence. Participants spent approximately five minutes in an immersive Cave-like system depicting a virtual bar with five virtual characters. On four occasions the projections were made to go white to trigger clearly identifiable anomalies in the audiovisual experience. Participants' physiological responses were measured throughout to investigate possible physiological correlates of these experienced anomalies. Analysis of subsequent interviews with participants suggests that these anomalies were subjectively experienced as breaks in presence. This is significant in the context of our research approach, which considers presence as a multilevel construct ranging from higher-level subjective responses to lower-level behavioral and automatic responses. The fact that these anomalies were also associated with an identifiable physiological signature suggests future avenues for exploring less intrusive ways of studying temporal fluctuations in presence during the course of the mediated experience itself. The findings also reveal that breaks in presence have multiple causes and can range in intensity, resulting in varying recovery times. In addition, presence can vary in intensity within the same space, suggesting that presence in an immersive virtual environment can fluctuate temporally and that spatial behavior is consistent with what would be expected in an equivalent real environment.
Journal Articles
Publisher: Journals Gateway
Presence: Teleoperators and Virtual Environments (2007) 16 (1): 100–110.
Published: 01 February 2007
Abstract
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We have set up a brain-computer interface (BCI) to be used as an input device to a highly immersive virtual reality CAVE-like system. We have carried out two navigation experiments: three subjects were required to rotate in a virtual bar room by imagining left or right hand movement, and to walk along a single axis in a virtual street by imagining foot or hand movement. In this paper we focus on the subjective experience of navigating virtual reality “by thought,” and on the interrelations between BCI and presence.
Journal Articles
Publisher: Journals Gateway
Presence: Teleoperators and Virtual Environments (2006) 15 (5): 500–514.
Published: 01 October 2006
Abstract
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Healthy participants are able to move forward within a virtual environment (VE) by the imagination of foot movement. This is achieved by using a brain-computer interface (BCI) that transforms thought-modulated electroencephalogram (EEG) recordings into a control signal. A BCI establishes a communication channel between the human brain and the computer. The basic principle of the Graz-BCI is the detection and classification of motor-imagery-related EEG patterns, whereby the dynamics of sensorimotor rhythms are analyzed. A BCI is a closed-loop system and information is visually fed back to the user about the success or failure of an intended movement imagination. Feedback can be realized in different ways, from a simple moving bar graph to navigation in VEs. The goals of this work are twofold: first, to show the influence of different feedback types on the same task, and second, to demonstrate that it is possible to move through a VE (e.g., a virtual street) without any muscular activity, using only the imagination of foot movement. In the presented work, data from BCI feedback displayed on a conventional monitor are compared with data from BCI feedback in VE experiments with a head-mounted display (HMD) and in a high immersive projection environment (Cave). Results of three participants are reported to demonstrate the proof-of-concept. The data indicate that the type of feedback has an influence on the task performance, but not on the BCI classification accuracy. The participants achieved their best performances viewing feedback in the Cave. Furthermore the VE feedback provided motivation for the subjects.
Journal Articles
Publisher: Journals Gateway
Presence: Teleoperators and Virtual Environments (2006) 15 (5): 553–569.
Published: 01 October 2006
Abstract
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An experiment was conducted in a Cave-like environment to explore the relationship between physiological responses and breaks in presence and utterances by virtual characters towards the participants. Twenty people explored a virtual environment (VE) that depicted a virtual bar scenario. The experiment was divided into a training and an experimental phase. During the experimental phase breaks in presence (BIPs) in the form of whiteouts of the VE scenario were induced for 2 s at four equally spaced times during the approximately 5 min in the bar scenario. Additionally, five virtual characters addressed remarks to the subjects. Physiological measures including electrocardiagram (ECG) and galvanic skin response (GSR) were recorded throughout the whole experiment. The heart rate, the heart rate variability, and the event-related heart rate changes were calculated from the acquired ECG data. The frequency response of the GSR signal was calculated with a wavelet analysis. The study shows that the heart rate and heart rate variability parameters vary significantly between the training and experimental phase. GSR parameters and event-related heart rate changes show the occurrence of breaks in presence. Event-related heart rate changes also signified the virtual character utterances. There were also differences in response between participants who report more or less socially anxious.
Journal Articles
Publisher: Journals Gateway
Presence: Teleoperators and Virtual Environments (2006) 15 (5): 599–610.
Published: 01 October 2006
Abstract
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Presence research relies heavily on empirical experiments involving subjects in mediated environments. Since presence is a complex, multidimensional concept, experiments on presence can be extremely resource intensive and produce large amounts of data of different types. As the presence community matures, we would like to suggest that data collected in experiments be made publicly available to the community. This will allow the verification of experimental results, comparison of results of experiments carried out in different laboratories, and evaluation of new data-analysis methods. This will, eventually, lead to consistency in approaches and increased confidence in results. In this paper we present the complete dataset from a large-scale experiment that we have carried out in highly immersive virtual reality. We describe the data we have gathered and give examples of the types of analysis that can be made based on that data.