Browsing by Author "Ma, Ruiqi"

Filter results by typing the first few letters
Now showing 1 - 2 of 2
  • No Thumbnail Available
    The Effects of In-vehicle Automation and Reliability on Driver Situation Awareness and Trust
    (2006-01-07) Ma, Ruiqi; David Kaber, Committee Chair
    The cognitive construct of situation awareness (SA) has not been well developed in the domain of driving. The objective of this study was to define a new transactional model of SA in various driving behaviors and activities, as influenced by automation and in-vehicle device use. Specifically, this study investigated the implications of adaptive cruise control (ACC) and cellular phone use in driving on a direct and objective measure of SA; investigate the effect of varying reliability of in-vehicle automation (navigation aids) on driver SA and trust; and assess differences in human trust in a human aid versus an automation aid in a simulated driving task. Twenty participants drove a virtual car and performed a freeway driving task (Experiment A) as well as a suburb navigation task (Experiment B). In the freeway driving, participants were required to drive using ACC or manual control modes, and received navigation information from one of two sources: a human or in-vehicle automation aid via cell phone or separate display screen, respectively. During the navigation driving, participants were required to drive through the suburban area following all traffic signs and directions from the navigation aid under different levels of information reliability (100%, 80% and 60%). A control condition was also used in which aids only presented a telemarketing survey and participants navigated using a map. Driver SA was assessed at the end of each experiment using a SA global assessment technique. Driver workload was collected at the same time using the NASA- TLX. Driver trust in the navigation aid information was measured using a subjective survey of initial subject trust expectations as well as a subjective rating at the close of each trial (end of Experiment B). Across both experiments, multiple dimensions of task performance were measured. MANOVA results for Experiment A revealed significant main effects for both ACC control mode and navigation aid type on driver performance, but no interaction effect. Findings were similar for driver SA except there was no effect of aid type. ANOVA results indicated use of the ACC system to improve driver SA and operational driver behaviors by reducing the task load in Experiment A. MANOVA results for Experiment B revealed only a significant effect of navigation aid reliability on driver performance and SA. ANOVA results revealed that perfect navigation information generally improved driving performance and driver SA for strategic driving behavior compared to unreliable navigation aid information and the control condition (task-irrelevant information). The results also revealed that drivers had higher initial trust expectations and expectation of fewer errors by the automation compared to the human. However, when participants experienced automation aid errors or inefficiency, their trust in the automation declined more sharply than trust in the human advisor. The results of this empirical work provide insight into the importance of driver SA in operational and strategic type driving tasks and associated actions. It identifies in-vehicle automation and devices as underlying factors in linkages of levels of SA to specific driving behaviors in the transactional model and serves to quantify the impact of the factors on driving performance. Validation of the proposed model and identification of other underlying factors may lead to its future use for predictive purposes.
  • No Thumbnail Available
    Telepresence and Performance in an Immersive Virtual Environment and Sporting Task
    (2003-10-30) Ma, Ruiqi; David B Kaber, Committee Chair
    The purpose of this research was to assess the relationship between telepresence and performance in a synthetic environment. Telepresence is believed to be a mental construct and to enhance task performance in teleoperations and virtual environments. Consequently, it has been identified as a design ideal for synthetic environments. However, there is a limited understanding of telepresence and its relation to task performance. This research involved examination of a range of synthetic environment design features (e.g., viewpoint and auditory cue type) that were suspected to influence telepresence and compared differences in telepresence and task performance caused by manipulations of these factors and task difficulty. A simulated basketball free-throw task was used in which subjects controlled the motions of a virtual basketball player. In addition to the basketball task performance (baskets/goals), subjects were required to report camera flashes in the virtual environment (stadium) and to simultaneously detect strobe light flashes in a real research laboratory. These tasks were designed as secondary-monitoring tasks and were intended to assess subject attention allocation to the virtual and real environments as an indicator of telepresence. Each subject was exposed to a single viewpoint condition including either an egocentric view, an exocentric view from behind the player, an exocentric view from the sideline of the court, or a selectable viewpoint. They were also exposed to four virtual sound conditions including task-relevant sounds, task-irrelevant sounds, a combination of sounds and no sound, as well as two visual display fidelity conditions including a low fidelity stadium composed of rendered walls surrounding the basketball court and a high fidelity stadium that displayed a texture of a crowd watching the game. Finally, the subjects experienced two task difficulty conditions including 2-point and 3-point shots. The order of presentation of the sound, fidelity and difficulty conditions was randomized. Subjective ratings and the objective, attention-based measure of telepresence were recorded during the experiment, along with task performance and workload. The results of the study provided evidence that the features of a simplistic synthetic environment, which include immersiveness (viewpoint) and auditory cue type significantly influence the sense of subjective telepresence. However, the objective, attention-based measure of telepresence did not prove to be sensitive to the experimental manipulations. Virtual task performance was significantly affected by task difficultly. This study also revealed significant effects of viewpoint and audio cue type on subjective workload. An analysis of trends on changes in telepresence and performance across settings of various virtual reality features provided compelling evidence that telepresence is a predictable experience unique from performance. However, the results of this analysis cannot be considered conclusive in terms of describing a causal relationship between telepresence and performance, in part, because of mixed findings across predictors. Beyond the relationship of telepresence and performance, this study provided further evidence of significant positive relations between telepresence and workload. There were no significant interaction effects among the virtual reality factors mentioned above in terms of performance, telepresence and workload. Although counter to expectation, and some previous research hypotheses on cross-modality interactions in virtual reality experiences, this finding was consistent with the findings of other prior empirical work. The lack of interaction effects on the response measures suggests that virtual reality design using multiple sensory channels could be relatively simple. However, this study did not examine all types of sensory cues including tactile and haptic. Furthermore, it is possible that more complex virtual environments for real-world applications might cause telepresence experiences more sensitive to, for example, cue conflicts.