Rajiv Khadka

Bio: Rajiv Khadka is an academic researcher from University of Wyoming. The author has contributed to research in topics: Virtual reality & Augmented reality. The author has an hindex of 3, co-authored 14 publications receiving 25 citations.

Virtual and Augmented Reality in the Disaster Management Technology: A Literature Review of the Past 11 years

Abstract: This study presents a systematic review of the literature on virtual reality (VR), augmented reality (AR) and Mixed Reality (MR) used in disaster management. We consider the factors such as publication type, publication year, application domain, and technology used. We surveyed papers from 2009 to 2019 available in the Web of Science and Google Scholar database, and 84 research articles were selected for the review study. After an extensive review of the literature, it was found that the XR technology is applied extensively in computer simulation modeling, interaction techniques, training, infrastructure assessment and reconnaissance, and public awareness areas of disaster management. We found diverse advantages, opportunities, and challenges of XR usage for disaster management, which are discussed in detail. Furthermore, current research gaps in the field of XR technology for disaster management technology, which are needed to better support disaster management, are identified and discussed in an effort to provide direction to the future research.

Evaluation of Scientific Workflow Effectiveness for a Distributed Multi-User Multi-Platform Support System for Collaborative Visualization

Abstract: Collaboration among research scientists across multiple types of visualizations and platforms is useful to enhance scientific workflow and lead to unique analysis and discovery. However, current analytic tools and visualization infrastructure lack sufficient capabilities to fully support collaboration across multiple types of visualizations, display/interactive systems, and geographically distributed researchers. We have combined, adapted, and enhanced several emerging immersive and visualization technologies into a novel collaboration system that will provide scientists with the ability to connect with other scientists to work together across multiple visualization platforms (i.e. stereoscopic versus monoscopic), multiple datasets (i.e. 3-Dimensional versus 2-Dimensional data), and multiple visualization techniques (i.e. volumetric rendering versus 2D plots). We have demonstrated several use cases of this system in materials science, manufacturing, planning, and others. In one such use case, our collaboration system imports material science data (i.e., graphite billet) and enable multiple scientists to analyze and explore the density change of graphite across immersive and non-immersive systems, which will help to understand the potential structural problem in it. We recruited scientists that work with the datasets we demonstrate in three use case scenarios and conducted an experimental user study to evaluate our novel collaboration system on scientific visualization workflow effectiveness. In this paper, we present the results on task completion time, task performance, user experience, and feedback among multiple and feedback among multiple geographically distributed collaborators using different multiple-platform for collaboration.

Body-Prop Interaction: Augmented Open Discs and Egocentric Body-Based Interaction for Exploring Immersive Visualizations

Abstract: Immersive Visualizations of 3-dimensional scientific data pose unique interaction challenges. One challenge is to be able to interact with the visual volumetric representations of data using direct manipulation in a way that facilitates exploration and discovery, yet maintains data relationships. In this paper, we present Body-Prop Interaction, a novel tangible multimodal interface for immersive visualizations. Our interaction technique combines multiple input and output modalities with 3D printed open discs that are tracked and augmented with virtual information. To demonstrate our technique, we implemented interactive tasks for a volume visualization of graphite billet data. While demonstrated for this type of data visualization, our novel interaction technique has the potential to be used to interact with other types of augmented and virtual reality.

Evaluation of Visual Perception Manipulation in Virtual Reality Training Environments to Improve Golf Performance

Abstract: In the real world, prior research in the field of perception and action has shown that individuals visually perceive objects differently based on their actual performance of an action on those objects, especially for sporting activities. For example, a golfer who performs well on putting a ball into the hole, will perceive that ball as larger (easier to hit) and the hole as larger (easier to put the ball in). We asked the following research question, can manipulation of visual perception of objects influence actual performance in the real world? Virtual objects are easily manipulated in Virtual Reality environments, therefore we investigated the use of Virtual Reality training where the properties of objects, such as size, were manipulated to influence perception on a golf putting task. In this paper, we present the results of our experimental user study. Putting performance increased after virtual reality training exposure when virtual objects were larger (perceived as easier to hit) and decreased when virtual objects were smaller (more difficult to hit). Our research has the potential to broaden the study of how virtual reality training can be used to improve sports training in a unique way.

Evaluation of Collaborative Actions to Inform Design of a Remote Interactive Collaboration Framework for Immersive Data Visualizations

Abstract: Data visualization and interaction is an important part of understanding and analyzing complex data. Immersive display systems provide benefits to exploration. In this paper, we present a user study to analyze co-located tasks and behaviors during a collaboration task. Results from this study helped us to identify patterns in co-located collaborative interaction to be able to better design remote collaborative environments. We discuss the challenges while interacting with data in an immersive data visualization environment and our design of a remote interactive collaboration framework for analysis and workflow of data visualizations. The goal of this framework is to preserve the benefits of physically co-located collaboration actions and add the benefits of virtual components that do not conform to real world restrictions.

Kicking to bigger uprights: Field goal kicking performance influences perceived size

Abstract: Perception relates not only to the optical information from the environment but also to the perceiver's performance on a given task. We present evidence that the perceived height and width of an American-football field goal post relates to the perceiver's kicking performance. Participants who made more successful kicks perceived the field goal posts to be farther apart and perceived the crossbar to be closer to the ground compared with participants who made fewer kicks. Interestingly, the current results show perceptual effects related to performance only after kicking the football but not before kicking. We also found that the types of performance errors influenced specific aspects of perception. The more kicks that were missed left or right of the target, the narrower the field goal posts looked. The more kicks that were missed short of the target, the taller the field goal crossbar looked. These results demonstrate that performance is a factor in size perception.

The State of the Art of Spatial Interfaces for 3D Visualization

Abstract: We survey the state of the art of spatial interfaces for 3D visualization. Interaction techniques are crucial to data visualization processes and the visualization research community has been calling for more research on interaction for years. Yet, research papers focusing on interaction techniques, in particular for 3D visualization purposes, are not always published in visualization venues, sometimes making it challenging to synthesize the latest interaction and visualization results. We therefore introduce a taxonomy of interaction technique for 3D visualization. The taxonomy is organized along two axes: the primary source of input on the one hand and the visualization task they support on the other hand. Surveying the state of the art allows us to highlight specific challenges and missed opportunities for research in 3D visualization. In particular, we call for additional research in: (1) controlling 3D visualization widgets to help scientists better understand their data, (2) 3D interaction techniques for dissemination, which are under-explored yet show great promise for helping museum and science centers in their mission to share recent knowledge, and (3) developing new measures that move beyond traditional time and errors metrics for evaluating visualizations that include spatial interaction.

The Sound of Being There: Audiovisual Cartography with Immersive Virtual Environments

Abstract: In recent years, immersion has become a frequently emphasized factor in the geovisualization research agenda. A principal reason for this growing interest is the assumption that immersive virtual environments (IVE) facilitate the formation of spatial presence, generally understood as the sense of “being there”. In a virtually mediated environment, the feeling of being there is of particular concern for cartographic ambitions, in terms of generating insights through geospatial representation. Current literature indicates that immersive VR systems stimulate the experience of spatial presence; however, this assumption is mainly based upon user studies in the visual communication channel. Moreover, research on IVE for geovisualization matters has to date been focused on visual-graphical rather than on auditive or even multisensory representations in virtual space. In this context, the present paper aims to evaluate the potential of audiovisual cartography with immersive virtual environments. Following a brief discussion of basic concepts, such as immersion, spatial presence and embodiment, we will integrate these aspects into a geovisualization immersion pipeline (GIP), as a framework with which to systematically link the technical and cognitive aspects of IVE. In the subsequent sections, we will examine this framework in the audio channel by analyzing how sound is implemented and perceived in GeoIVE. As we shall see, the positive effect of a combined audio-visual vs. exclusively visual presentation is supported by a series of user studies of sound effects, making audiovisual cartography with IVE a rich and worthwhile field of research.

An Empirical Evaluation of Asymmetric Synchronous Collaboration Combining Immersive and Non-Immersive Interfaces Within the Context of Immersive Analytics

Abstract: Collaboration is an essential part of data analysis, allowing multiple users to combine their expertise and to debate about the interpretation of data discoveries using their contextual knowledge. The design of collaborative interfaces within the context of Immersive Analytics remains challenging, particularly due to the various user-centered characteristics of immersive technologies. In this article, we present the use case of a system that enables multiple users to synchronously explore the same data in a collaborative scenario that combines immersive and non-immersive interfaces in an asymmetric role setup. Such a setup allows for bridging the gap when applying heterogeneous display and interaction technologies, enabling each analyst to have an independent and different view of the data, while maintaining important collaborative aspects during the joint data exploration. We developed an immersive VR environment (head-mounted display, 3D gestural input) and a non-immersive desktop terminal (monitor, keyboard and mouse) centered around spatio-temporal data exploration. Supported through a real-time communication interface, synchronous collaborative features are integrated in both interfaces, facilitating the users in their ability to establish a shared context and to make spatio-temporal references. We conducted an empirical evaluation with five participant pairs (within-subject design) to investigate aspects of usability, user engagement, and collaboration during a confirmative analysis task. Synthesis of questionnaire results in combination with additional log file analysis, audio activity analysis, and observations, revealed good usability scores, high user engagement, as well as overall close and balanced collaboration of enthusiastic pairs during the task completion independent of their interface type, validating our system approach in general. Further supported through the self-constructed Spatio-Temporal Collaboration Questionnaire, we are able to contribute with discussion and considerations of the presented scenario and the synchronous collaborative features for the design of similar applications.

The Challenges in Modeling Human Performance in 3D Space with Fitts' Law

Abstract: With the rapid growth in virtual reality technologies, object interaction is becoming increasingly more immersive, elucidating human perception and leading to promising directions towards evaluating human performance under different settings. This spike in technological growth exponentially increased the need for a human performance metric in 3D space. Fitts' law is perhaps the most widely used human prediction model in HCI history attempting to capture human movement in lower dimensions. Despite the collective effort towards deriving an advanced extension of a 3D human performance model based on Fitts' law, a standardized metric is still missing. Moreover, most of the extensions to date assume or limit their findings to certain settings, effectively disregarding important variables that are fundamental to 3D object interaction. In this review, we investigate and analyze the most prominent extensions of Fitts' law and compare their characteristics pinpointing to potentially important aspects for deriving a higher-dimensional performance model. Lastly, we mention the complexities, frontiers as well as potential challenges that may lay ahead.