Arbor 3D: an interactive environment for examining phylogenetic and taxonomic trees in multiple dimensions.

Haptic interaction in slow virtual environments (VEs) can become unstable due to the phase lag introduced in the control loop by the slow update rate of the VE. Increasing the physical damping and/or limiting the contact stiffness rendered to users can mitigate the destabilizing effect of the low VE update rate. However, large physical damping and compliant virtual contacts decrease the sense of presence in VEs, especially during interaction with rigid virtual objects. To increase the maximum virtual contact stiffness that can be rendered to users without increasing the interface damping, this paper proposes a control strategy based on multirate wave communications between a haptic interface and a VE updated at a slow and fixed rate. The multirate wave communications are shown to be guaranteed passive only if the decrease of the wave sampling rate at the connection between the haptic interface and the VE does not cause aliasing. Therefore, an antialiasing low-pass filter is placed before the wave rate drop in the communications. The passivity condition is verified analytically and numerically for multirate haptic interaction in VEs with various contact stiffnesses and update rates. The transparency of haptic interaction in slow VEs to which users connect via passive multirate wave communications is investigated analytically in the frequency domain. Experiments validate that passive multirate wave communications can render stiffer contact in slow VEs than conventional direct coupling, and illustrate the destabilizing effect of the aliasing caused by the sampling rate drop in the communications.

The challenges of measuring, managing, and predicting negative side effects (i.e. cybersickness) during virtual environment (VE) interaction and unwanted aftereffects continue to persist. Most assessments have been limited to subjective questionnaires. This study investigated the effects of VE interaction on nausea (gastric activity) and the development of a quantitative model affording cybersickness prediction. This cybersickness state estimation model (CSEM) offers a quantitative (i.e. physiological based) predictability to cybersickness. The model relates time, recordable gastric activity using electrogastrogram (EGG) measures as a physiological predictor and subjective sickness estimates. This work employs neural network algorithms to model user state associated with cybersickness. Neural network models were designed, trained, and tested to determine the network trainability and accuracy. Mean SSQ total severity scores indicate significant differences between conditions. All CSEM models had a low sum of squared error. The models were found to be accurate in predicting cybersickness from unseen data.

Interactive Virtual Environments (VEs) have the potential to increase student interest in soil science. Accordingly a bespoke ‘soil atlas’ was created using Java3D as an interactive 3D VE, to show soil information in the context of (and as affected by) the over-lying landscape. To display the below-ground soil characteristics, four sets of artistic illustrations were produced, each set showing the effects of soil organic-matter density and water content on fungal density, to determine potential for visualisations and interactivity in stimulating interest in soil and soil illustrations, interest being an important factor in facilitating learning. The illustrations were created using 3D modelling packages, and a wide range of styles were produced. This allowed a preliminary study of the relative merits of different artistic styles, scientific-credibility, scale, abstraction and ‘realism’ (e.g. photo-realism or realism of forms), and any relationship between these and the level of interest indicated by the study participants in the soil visualisations and VE. The study found significant differences in mean interest ratings for different soil illustration styles, as well as in the perception of scientific-credibility of these styles, albeit for both measures there was considerable difference of attitude between participants about particular styles. There was also found to be a highly significant positive correlation between participants rating styles highly for interest and highly for scientific-credibility. There was furthermore a particularly high interest rating among participants for seeing temporal soil processes illustrated/animated, suggesting this as a particularly promising method for further stimulating interest in soil illustrations and soil itself.

Geometric acoustic modeling systems spatialize sounds according to reverberation paths from a sound source to a receiver to give an auditory impression of a virtual 3D environment. These systems are useful for concert hall design, teleconferencing, training and simulation, and interactive virtual environments. In many cases, such as in an interactive walkthrough program, the reverberation paths must be updated within strict timing constraints ‐ e.g., as the sound receiver moves under interactive control by a user. In this paper, we describe a geometric acoustic modeling algorithm that uses a priority queue to trace polyhedral beams representing reverberation paths in best‐first order up to some termination criteria (e.g., expired time‐slice). The advantage of this algorithm is that it is more likely to find the highest priority reverberation paths within a fixed time‐slice, avoiding many geometric computations for lower‐priority beams. Yet, there is overhead in computing priorities and managing the priority queue. The focus of this paper is to study the trade‐offs of the priority‐driven beam tracing algorithm with different priority functions. During experiments computing reverberation paths between a source and a receiver in a 3D building environment, we find that priority functions incorporating more accurate estimates of source‐to‐receiver path length are more likely to find early reverberation paths useful for spatialization, especially in situations where the source and receiver cannot reach each other through trivial reverberation paths. However, when receivers are added to the environment such that it becomes more densely and evenly populated, this advantage diminishes.

The use of detailed building plans and models is common in the construction management domain. Also there is increasing interest in the reuse of such models to realize 3D interactive virtual environments to aid model refinement and for use as training environments, for example virtual site visits. Unfortunately, the development of interactive virtual environments is both time consuming and technically difficult. One successful approach is the reuse of gaming technology to provide the underlying virtual environment and to allow developers to focus on importing appropriate content, e.g. building geometry and textures. Building Information Modelling (BIM) provides a rich source of building data and is an ideal basis for constructing realistic virtual environments. This paper overviews the conversion from BIM to game engines and specifically from the BIM tool Revit to the Unity3D game engine in a case study.

The complex nature of virtual environments customarily hinders users to interact in a natural, intuitive and optimal way. Different user characteristics are hardly taken into account when designing 3D user interfaces for virtual environments. We envision that user interaction in virtual environments can be enhanced by integrating adaptation and personalization into 3D user interfaces. Through our research, we aim to provide adaptive and personalized 3D user interfaces for enhancing user interaction in virtual environments. The establishment of a user model becomes an important first step to facilitate adaptation and personalization to the user. In order to partly construct the user model, we carried out an experiment on 3D target acquisition task with four user groups (differing in experience level and gender). In this paper, we present a general user model that will enable first-time users to benefit instantly from adaptation and personalization in virtual environments.Keywordsvirtual environmentsadaptive 3D interfacesuser model

Art students frequently need to draw statues as part of their assignments. Perspective, lighting, and proportion are key issues in developing students’ skills, but they can be challenging to control in real life. The work reported in this paper aims to provide better support for arts and design students in the early stages of learning by demonstrating a 3D interactive virtual environment that allows students to control all angles of the statues to acquire the required perspective. It also allows them to manipulate the lighting position to apply shading techniques. Students can choose hard lighting, which means the light would be intense and originates from a specific point, or a more natural light, where the light and shadows are softer and do not contrast as much. Instructors can likewise place further objects in the environment surrounding the statue to teach the students the concept of proportion. The 3D environment has been developed using Unity Engine and deployed for Desktop and Android devices. It accommodates both pre-existing models and models imported from a database. The utility of the 3D virtual environment has been assessed by conducting a number of studies with students and lecturers of an Arts and Design Faculty.

In this paper, we describe the development of an interactive virtual environment whose objective is to improve undergraduate students' representational fluency in surveying mathematics. One problem with teaching surveying is a general decline in the math skills of students taking surveying courses, and a decline in the students' ability to transfer these concepts into practice in the context of surveying. In the paper, we explain how an interactive virtual environment that presents multiple interconnected representations of math and geometry concepts - dynamic visual objects, symbolic or numeric expressions, and written and verbal explanations simultaneously on the computer screen - can help students acquire the math and geometry skills necessary to perform surveying tasks such as chaining and triangulations and coordinate calculations.

The project investigates the possibility of visualizing open source data in a 3D interactive virtual environment. We propose a new tool, 'ViBe'. We programmed 'ViBe' using Unity for its compatibility with HTC VIVE glasses for virtual reality (VR). ViBe offers an abstract visualization of open source data in a 3D interactive environment. The ViBe environment entails three main topics a) inhabitants, b) environmental factors, and c) land-use; acting as representatives of parameters for cities and urban design. Berlin serves as a case study. The data sets used are divided according to Berlin's twelve administrative districts. The user immerses into the virtual environment where they can choose, using the HTC Vive controllers, which district (or Berlin as a whole) they want information for and which topics they want to be visualized, and they can also teleport back and forth between the different districts. The goal of this project is to represent different urban parameters an abstract simulation where we correlate the corresponding data sets. By experiencing the city through visualized data, ViBe aims to provide the user with a clearer perspective onto the city and the relationship between its urban parameters. ViBe is designed for adults and kids, urban planners, politicians and real estate developers alike.

Virtual environments systems based on immersive projection technologies (IPTs) offer users the possibility of collaborating intuitively in a 3D environment. While considerable work has been done to examine interaction in desktop-based collaborative virtual environments (CVEs), there are currently no studies for collaborative interaction using IPTs. The aim of this paper is to examine how immersive technologies support interaction and to compare this to the experience with desktop systems. A study of collaboration is presented where two partners worked together using networked IPT environments. The data collected included observations, analysis of video and audio recordings, questionnaires and debriefing interviews from both IPT sites. This paper focuses on the successes and failures in collaboration through detailed examination of particular incidents during the interaction. We compare these successes and failures with the findings of a study by Hindmarsh, Fraser, Heath, & Benford (Computer Supported Collaborative Work, CSCW'98, 1998, pp. 217–226) that examined object-focused interaction on a desktop-based CVE system. Our findings identify situations where interaction is better supported with the IPT system than the desktop system, and situations where interaction is not as well supported. We also present examples of how social interaction is critical to seamless collaboration.

Training through Multi-modal Collaborative Virtual Laboratory (MMCVL) aims at developing or improving skills of students without the need of them being physically present. MMCVL addresses the problems faced by the current education system such as lack of resources and safe use of expensive laboratory equipment. It also provides a means for easy collaboration between students and teachers from different universities and schools. Multimedia data in terms of 3D mesh, skeleton, audio and virtual object physics interaction are incorporated in MMCVL to provide a 3D Tele-Immersion environment. The system uses low-cost RGB-D cameras such as Microsoft Kinect V2 to capture and generate 3D model of the person by extracting him/her from the entire captured data and immersing it in different interactive virtual environments. Different lab environments can be virtually created to provide for and replace the real laboratories. Object interactions allow for users to interact with the virtual objects present in the scene similar to real lab setup. Recording module of the toolkit allows future reference for training and testing of the student. The system also facilitates virtual feedback by giving the correct measurements, video demonstrations as well as audio communication with the collaborating teacher. Two different Chemistry experiments were performed to evaluate the user experience and usability aspects of MMCVL. Results obtained from the user study analysis prove the system to be fun and realistic, and at the same time engaging and motivating for learning laboratory experiments.

Visual effects and elements in video games and interactive virtual environments can be applied to transfer (or delegate) non-visual perceptions (e.g., proprioception, presence, pain) to players and users, thus increasing perceptual diversity via the visual modality. Such elements or effects are referred to as visual delegates (VDs). Current findings on the experiences that VDs can elicit relate to specific VDs, not to VDs in general. Deductive and comprehensive VD evaluation frameworks are lacking. We analyzed VDs in video games to generalize VDs in terms of their visual properties. We conducted a systematic paper analysis to explore player and user experiences observed in association with specific VDs in user studies. We conducted semi-structured interviews with expert players to determine their preferences and the impact of VD properties. The resulting VD framework (VD-frame) contributes to a more strategic approach to identifying the impact of VDs on player and user experiences.

To determine the mechanism of molecular evolution, molecular biologists need to carry out reconciliation work. In reconciliation work, they compare the relation between two heterogeneous phylogenetic trees and the relation between a phylogenetic tree and a taxonomic tree. Phylogenetic trees and taxonomic trees are referred to as ordered trees and a reconciliation graph is constructed from two ordered trees. In the reconciliation graph, the leaf nodes of the two ordered trees face each other. Furthermore, leaf nodes with the same label name are connected to each other by an edge. To perform reconciliation work efficiently, it is necessary to find the state with the minimum number of crossovers of edges between leaf nodes. Reducing crossovers in a reconciliation graph is the combinatorial optimization problem that finds the state with the minimum number of crossovers. In this chapter, a novel bio-inspired heuristic called island-model-based distributed modified extremal optimization (IDMEO) is presented. This heuristic is a hybrid of population-based modified extremal optimization (PMEO) and the distributed genetic algorithm using the island model that is used for reducing crossovers in a reconciliation graph.

Taxonomic trees are based on a large number of characters while phylogenetic trees consider single or multiple traits of a fixed set of species. We compute theclade-by-clade similarity between two trees as Taxonomic fidelity Index (F). In contrast to monogenic traits, the topology of phylogenetic trees increasingly resembles the taxonomic tree

In an initial study, we characterized the properties of human reach motion in the presence or absence of visuo-haptic feedback in real and Immersive Virtual Environments (IVEs) or virtual reality within a participant’s maximum arm reach. Our goal is to understand how physical reaching actions to the perceived location of targets in the presence or absence of visuo-haptic feedback are different between real and virtual viewing conditions. Typically, participants reach to the perceived location of objects in the three-dimensional (3D) environment to perform selection and manipulation actions during 3D interaction in applications such as virtual assembly or rehabilitation. In these tasks, participants typically have distorted perceptual information in the IVE as compared to the real world, in part due to technological limitations such as minimal visual field of view, resolution, latency, and jitter. In an empirical evaluation, we asked the following questions: (i) how do the perceptual differences between virtual and real world affect our ability to accurately reach to the locations of 3D objects, and (ii) how do the motor responses of participants differ between the presence or absence of visual and haptic feedback? We examined factors such as velocity and distance of physical reaching behavior between the real world and IVE, both in the presence or absence of visuo-haptic information. The results suggest that physical reach responses vary systematically between real and virtual environments, especially in situations involving the presence or absence of visuo-haptic feedback. The implications of our study provide a methodological framework for the analysis of reaching motions for selection and manipulation with novel 3D interaction metaphors and to successfully characterize visuo-haptic versus non-visuo-haptic physical reaches in virtual and real-world situations.