Human-computer interaction design principles largely focus on static representations and have yet to fully incorporate theories of perception appropriate for the dynamic multimodal interactions inherent to virtual environment (VE) interaction. Theories of direct perception, in particular affordance theory, may prove particularly relevant to enhancing VE interaction design. The present research constructs a conceptual model of how affordances are realized in the natural world and how lack of sensory stimuli may lead to realization failures in virtual environments. Implications of the model were empirically investigated by examining three affordances: passability, catchability, and flyability. The experimental design involved four factors for each of the three affordances and was implemented as a 2 [subscript IV] [superscript 4-1] fractional factorial design. The results demonstrated that providing affording cues led to behavior closely in-line with real-world behavior. More specifically, when given affording cues participants tended to rotate their virtual bodies when entering narrow passageways, accurately judge balls as catchable, and fly when conditions warranted it. The results support the conceptual model and demonstrate 1) that substituting designed cues via sensory stimuli in available sensory modalities for absent or impoverished modalities may enable the perception of affordances in VEs; 2) that sensory stimuli substitutions provide potential approaches for enabling the perception of affordances in a VE which in the real world are cross-modal; and 3) that affordances relating to specific action capabilities may be enabled by designed sensory stimuli. This research lays an empirical foundation for a science of VE design based on choosing and implementing design properties so as to evoke targeted user behavior

Advances in computer networks and rendering systems facilitate the creation of distributed collaborative environments in which the distribution of information at remote locations allows efficient communication. Particularly challenging are distributed interactive Virtual Environments (VE) that allow knowledge sharing through 3D information. In a distributed interactive VE the dynamic shared state represents the changing information that multiple machines must maintain about the shared virtual components. One of the challenges in such environments is maintaining a consistent view of the dynamic shared state in the presence of inevitable network latency and jitter. A consistent view of the shared scene will significantly increase the sense of presence among participants and facilitate their interactive collaboration. The purpose of this work is to address the problem of latency in distributed interactive VE and to develop a conceptual model for consistency maintenance in these environments based on the participant interaction model. A review of the literature illustrates that the techniques for consistency maintenance in distributed Virtual Reality (VR) environments can be roughly grouped into three categories: centralized information management, prediction through dead reckoning algorithms, and frequent state regeneration. Additional resource management methods can be applied across these techniques for shared state consistency improvement. Some of these techniques are related to the systems infrastructure, others are related to the human nature of the participants (e.g., human perceptual limitations, area of interest management, and visual and temporal perception). An area that needs to be explored is the relationship between the dynamic shared state and the interaction with the virtual entities present in the shared scene. Mixed Reality (MR) and VR environments must bring the human participant interaction into the loop through a wide range of electronic motion sensors, and haptic devices. Part of the work presented here defines a novel criterion for categorization of distributed interactive VE and introduces, as well as analyzes, an adaptive synchronization algorithm for consistency maintenance in such environments. As part of the work, a distributed interactive Augmented Reality (AR) testbed and the algorithm implementation details are presented. Currently the testbed is part of several research efforts at the Optical Diagnostics and Applications Laboratory including 3D visualization applications using custom built head-mounted displays (HMDs) with optical motion tracking and a medical training prototype for endotracheal intubation and medical prognostics. An objective method using quaternion calculus is applied for the algorithm assessment. In spite of significant network latency, results show that the dynamic shared state can be maintained consistent at multiple remotely located sites. In further consideration of the latency problems and in the light of the current trends in interactive distributed VE applications, we propose a hybrid distributed system architecture for sensor-based distributed VE that has the potential to improve the system real-time behavior and scalability.

This dissertation investigated the effects of complex backgrounds on mental rotation. Stimulus familiarity and background familiarity were manipulated. It systematically explored how familiarizing participants to objects and complex backgrounds affects their performance on a mental rotation task involving complex backgrounds. This study had 113 participants recruited through the UCF Psychology SONA system. Participants were familiarized with a stimulus in a task where they were told to distinguish the stimulus from 3 other stimuli. A similar procedure was used to familiarize the backgrounds. The research design was a 2 stimulus familiarity (Familiarized with the Target Stimulus, not familiarized with the Target Stimulus) by 2 background familiarity (Familiarized with Target Background, not familiarized with Target Background 1) by 2 stimulus response condition (Target Stimulus, Non-Target Stimulus) by 3 background response condition (Target Background, Non-Target Background, Blank Background) by 12 degree of rotation (0, 30, 60, 90, 120, 150, 180, 210, 240, 270, 300, 330) mixed design. The study utilized target stimulus and target background familiarity conditions as the between-subjects variables. Background, stimulus, and degree of rotation were within-subjects variables. The participants' performance was measured using reaction time and percent of errors. Reaction time was computed using only the correct responses. After the familiarization task, participants engaged in a mental rotation task featuring stimuli and backgrounds that were present or not present in the familiarization task. A 2 (stimulus familiarization condition) by 2 (background familiarization condition) by 2 (stimulus response condition) by 3 (background response condition) by 12 (degree of rotation) mixed ANOVA was computed utilizing reaction time and percent of errors. Results suggest that familiarity with the Target Background had the largest effect on improving performance across response conditions. The results also suggest that familiarity with both the Target Stimulus and Target Background promoted inefficient mental rotation strategies which resulted in no significant differences between participants familiarized with neither the Target Stimulus nor the Target Background. Theoretical conclusions are drawn about stimulus familiarity and background familiarity. Future studies should investigate the effects of long term familiarity practice on mental rotation and complex backgrounds.

Yes / Mixed reality (MR) is a powerful interactive technology for new types of user experience. We present a semantic‐based interactive MR framework that is beyond current geometry‐based approaches, offering a step change in generating high‐level context‐aware interactions. Our key insight is that by building semantic understanding in MR, we can develop a system that not only greatly enhances user experience through object‐specific behaviours, but also it paves the way for solving complex interaction design challenges. In this paper, our proposed framework generates semantic properties of the real‐world environment through a dense scene reconstruction and deep image understanding scheme. We demonstrate our approach by developing a material‐aware prototype system for context‐aware physical interactions between the real and virtual objects. Quantitative and qualitative evaluation results show that the framework delivers accurate and consistent semantic information in an interactive MR environment, providing effective real‐time semantic‐level interactions.

This research examined the processes involved when one is acquiring spatial knowledge while traversing an environment, integrating that knowledge into mental representations, and subsequently relying on that knowledge to successfully perform wayfinding. Particularly, the conducted studies aimed to provide evidence reflecting on two ongoing debates: the distinctions between types of knowledge embedded in mental maps, and the unconfirmed sequential or simultaneous nature of the acquisition and integration of those types. The experiments reported in this manuscript addressed drawbacks in existing research by manipulating opportunities for the acquisition of point and route knowledge (two of the potentially distinct knowledge types), and by testing participants' capacity to integrate their acquired knowledge in the context of environmental affordances. Participants in the conducted studies underwent environmental training exposures targeted at providing a) primarily point knowledge or b) route knowledge acquisition, and they also completed a set of knowledge measures tapping point, route, and configuration knowledge. Finally, participants completed tests of wayfinding capacity to demonstrate their ability to rely on integrated mental maps for successful wayfinding. Results of the two conducted studies provided substantial evidence that there are distinct types of knowledge that may be acquired and quantifiably measured, and that spatial knowledge can be acquired in parallel, not necessarily in sequence, across knowledge types. Critically, some knowledge types may also develop in exclusion to others especially for individuals with particular spatial abilities and predispositions. Accordingly, it is likely that previous research indicating sequential spatial knowledge development may be reflecting differential acquisition as a combination of population capabilities and knowledge measurement research methodologies. Finally, the results demonstrate that individual differences, training modalities, and environment iv features have complex, interacting effects on spatial cognition and that no one factor predominantly determines individuals' ability to acquire, integrate, or employ spatial knowledge.

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Navigation proficiency - the ability to find and recall new and familiar locations - varies widely among individuals (e.g., Schinazi, Epstein, Nardi, Newcombe, & Shipley, 2013; Weisberg, Schinazi, Newcombe, Shipley, & Epstein, 2014). The cognitive processes that support effective navigation have been theoretically sketched out (e.g., Wolbers & Hegarty, 2010), but how do those processes contribute to aspects of and individual differences in navigation behavior? Using a virtual environment to assess navigation proficiency (Weisberg et al., 2014), we conducted two studies to investigate whether individual differences in navigating meaningfully relate to memory capacity (Study1) and navigation strategy (Study 2). Results from Study 1 suggest that working memory capacity may limit some participants' ability to build accurate cognitive maps. Using a virtual environment paradigm based on the rodent T-maze (Marchette, Bakker, & Shelton, 2011), Study 2 shows that good navigators do not prefer to use a place-based strategy over a response-based strategy, but there was an interaction between strategy selection and goals found. Good navigators who used a place-based strategy found more goals than good navigators who used a response-based strategy; the opposite was true for bad navigators. Emerging from this set of studies is a richer picture of how individual differences in cognitive traits (i.e., working memory capacity), and strategy choice relate to navigation proficiency. / Psychology