Collaborative Virtual Environment System Research Articles

INC-Hg: An Intelligent Collaborative Haptic-Gripper Virtual Reality System

Collaborative Virtual Environments (CVE) have shown potential to be an effective social skill training platform for children with Autism Spectrum Disorders (ASD) to learn and practice collaborative and communication skills through peer interactions. However, most existing CVE systems require that appropriately matched partners be available at the same time to promote interaction, which limits their applicability to some community settings due to scheduling constraints. A second shortcoming of these more naturalistic peer-based designs is the intensive resources required to manually code the unrestricted conversations that occurred during the peer-based interactions. To preserve the benefits of CVE-based platforms and mitigate some of the resource limitations related to peer availability, we developed an Intelligent Collaborative Haptic-Gripper System (INC-Hg). This system provides an intelligent agent partner who can understand, communicate, and haptically interact with the user, without requiring the presence of another human peer. The INC-Hg operates in real time and thus is able to perform collaborative training tasks at any time and at the user's pace. INC-Hg can also record the real-time data regarding spoken language and task performance, thereby greatly reducing the resource burden of communication and interaction performance analysis. A preliminary usability study with 10 participants with ASD (ages 8–12 years) indicated that the system could classify the participant's utterances into five classes with an accuracy of 70.34%, which suggested the potential of INC-Hg to automatically recognize and analyze conversational content. The results also indicated high accuracies of the agent to initiate a conversation (97.56%) and respond to the participants (86.52%), suggesting the capability of the agent to conduct proper conversations with the participants. Compared to the results of human-to-human collaborative tasks, the human-to-agent mode achieved higher average collaborative operation ratio (61% compared to 40%) and comparable average frequencies for Initiations and Responses among the participants with ASD. These results offer preliminary support as well as areas of improvement regarding the agent's ability to respond to participants, work with participants to complete tasks, engage in back-and-forth conversations, and support the potential of the agent to be a useful partner for individuals with ASD completing CVE tasks.

Virtual reality barrel shaft design and assembly planning accompany with CAM

Abstract This paper proposes the virtual reality concept to design and assembly planning for a barrel shaft. The shaft model was created on CAM and digital verification for effective functional design together with simulation as traditional method. Presently, virtual reality technology is sophisticated to mechanical components design and assembly animation which can help a design engineer in order to show possibility alternative assembly planning and achieve optimization. Collaborative virtual environment system was used to create the assembly plan animation.

Design and Evaluation of a Collaborative Virtual Environment (CoMove) for Autism Spectrum Disorder Intervention

Autism Spectrum Disorder (ASD) is a neurodevelopmental disorder characterized in part by core deficits in social interaction and communication. A collaborative virtual environment (CVE), which is a computer-based, distributed, virtual space for multiple users to interact with one another and/or with virtual items, has the potential to support flexible, safe, and peer-based social interactions. In this article, we presented the design of a CVE system, called CoMove, with the ultimate goals of measuring and potentially enhancing collaborative interactions and verbal communication of children with ASD when they play collaborative puzzle games with their typically developing (TD) peers in remote locations. CoMove has two distinguishing characteristics: (i) the ability to promote important collaborative behaviors (including information sharing, sequential interactions, and simultaneous interactions) and to provide real-time feedback based on users’ game performance; as well as (ii) an objective way to measure and index important aspects of collaboration and verbal-communication skills during system interaction. A feasibility study with 14 pairs—7 ASD/TD pairs and 7 TD/TD pairs—was conducted to initially test the feasibility of CoMove. The results of the study validated the system feasibility and suggested its potential to index important aspects of collaboration and verbal communication.

Hand-in-Hand: A Communication-Enhancement Collaborative Virtual Reality System for Promoting Social Interaction in Children with Autism Spectrum Disorders.

Children with autism spectrum disorders (ASD) often exhibit impairments in communication and social interaction, and thus face various social challenges in collaborative activities. Given the cost of ASD intervention and lack of access to trained clinicians, technology-assisted ASD intervention has gained momentum in recent years. In this paper, we present a novel collaborative virtual environment (CVE) based social interaction platform for ASD intervention. The development of CVE technology for ASD intervention may lead to the creation of a novel low-cost intervention environment that will foster collaboration with peers and provide flexibility in communication. The presented Communication-Enhancement CVE system, Hand-in-Hand, allows two children to play a series of interactive games in a virtual reality environment by using simple hand gestures to collaboratively move virtual objects that are tracked in real-time via cameras. Further, these games are designed to promote natural communication and cooperation between the users via the presented Communication-Enhancement mode that allows users to share information and discuss game strategies using gaze and voice based communication. The results of a feasibility study with 12 children with ASD and 12 typically developing peers show that this system was well accepted by both the children with and without ASD, improved their cooperation in game play, and demonstrated the potential for fostering their communication and collaboration skills.

On consistency and security issues in collaborative virtual environment systems

This paper survey security issues in collaborative virtual environments (CVEs) systems. In CVE, multiple users work on different computers which are interconnected through different networks to interact in a shared virtual world. Due to the nature of the geographically disperse users and their connection via different networks, there are numerous security threats that denied fulfillments of most important CVE requirements which have been ignored (e.g. consistency). In this paper, we outlined the types of collaborative virtual environment applications that can be affected by security threats and attacks, it discussed some of the most important CVE systems security requirements, and then discussed the different types of security threats and attacks related to CVE systems security requirements. Finally, we describe the state of the art of CVE system security. Key words: Collaborative virtual environments (CVE), security requirement, threats, attack.

A New Partitioning Method Based on AOI Model Matching in CVE Systems

Collaborative Virtual Environment (CVE) system supports a large number of users to explore a virtual world and interact with each other through networks, so one of the key issues in the design of scalable CVE systems is the partitioning problem. Existing partitioning algorithms in CVE systems based on multiple-server architecture, in our opinion, hardly consider the communication character of virtual environment. In this paper, we propose a new partitioning method based on area of interest (AOI) model matching to improve the quality of partitioning. The experimental results show preliminarily that our partitioning approach based on AOI model matching does decrease the traffic among the servers in the system and improve the partitioning performance.

A hierarchical architecture for improving scalability and consistency in CVE systems

Existing client/server architecture with a multiple server has the capacity constraint of users due to the fixed number of servers. A hierarchical architecture based on the tailoring tree model for improving scalability and consistency in the collaborative virtual environment (CVE) is described. In our architecture, the main server, region servers and clients maintain the state of the CVE together. In order to improve the scalability and consistency, computing resources and communication resources should be effectively assigned. Two algorithms are proposed to solve the resource assignment problem in the hierarchical architecture: a dynamic clustering algorithm partitions the virtual environment according to the current load, which can effectively assign computing resources; a time-bounding-box-based filtering scheme is used to reduce the traffic, which can effectively assign communication resources. Experimental results show that the hierarchical architecture with our algorithms has a reasonable assignment of computing resources and communication resources at the same time, and, indeed, improves the scalability and consistency.

A Self-Adaptive Filtering Algorithm Based on Consistency QoS in CVE Systems

In the Collaborative Virtual Environments (CVE), there is a conflict between maintaining the state consistency and supporting more users sharing the virtual environment. A self-adaptive message filtering algorithm based on consistency QoS is proposed to improve both the consistency and scalability. Each user in the virtual environment has active workspace, influence area and dormancy zone according to the different requirement of consistency QoS. Time-space bounding sphere is defined to predict user’s active workspace to provide high consistency QoS. When two users’ time-space bounding spheres overlap, the key updates of two users are sent to each other in time to keep the state consistency. A self-adaptive threshold function model is used when two users’ influence areas overlap, which makes a tradeoff between consistency and scalability and provides a medium consistency QoS. Heart-beat packets are sent when two users’ dormancy zones overlap to filter messages in order to reduce the system traffic since the low consistency QoS is required. The results of traffic test and consistency QoS test in the experiment show that our algorithm can maintain the state consistency and reduce the consumption of network resources simultaneously.

MACVE: A Mobile Agent Based Framework for Large-Scale Collaborative Virtual Environments

The Collaborative Virtual Environment (CVE) is a promising technology which provides an online shared virtual world for geographically dispersed people to interact with each other. However, the scalability of existing CVE systems is limited due to the constraints in processing power and network speed of each participating host. In this paper, a mobile agent based framework for large-scale CVE, MACVE, is proposed to support a large number of concurrent participants in a CVE with a large amount of evolving virtual entities. In MACVE, the CVE system is decomposed into a group of collaborative mobile agents, each of which is responsible for an independent system task. These agents can migrate or clone dynamically at any suitable participating host including traditional servers and qualified user hosts to avoid the potential bottleneck, which can improve the scalability of CVE. Our prototype system has demonstrated the feasibility of the proposed framework.

AN AUTONOMOUS DECENTRALIZED MULTI-SERVER FRAMEWORK FOR LARGE SCALE COLLABORATIVE VIRTUAL ENVIRONMENTS

Collaborative Virtual Environment (CVE) is a promising technology which provides an online shared virtual world to the geographically dispersed people to interact with each other. However, the scalability of existing CVE system is limited due to the constraints in processing power and network speed of each participating host. Large scale CVE (LCVE) that supports a large number of concurrent participants and a large amount of evolving virtual entities is not easy to achieve. In this paper, an autonomous decentralized grid based mobile agent framework for large scale CVE — MACVE is proposed. In MACVE, LCVE software system is decomposed into a group of collaborative mobile agents, each of which is responsible for an independent system task. Agents can migrate or clone dynamically at any suitable participating host (grid node) include traditional servers and qualified user hosts to avoid bottleneck, which can improve the scalability of LCVE. Therefore, MACVE is a logically multi-server architecture while the server workload is autonomously decentralized. Our system prototype and evaluation has demonstrated the feasibility of the proposed framework.

Leaving the World Behind: Supporting Group Collaboration Patterns in a Shared Virtual Environment for Product Design

Virtual reality technology is increasingly being applied to globally distributed teams engaged in collaborative product design. Observations of product design teams have suggested four distinct patterns of collaboration—complementary, competitive, peer-to-peer, and leader-follower. Another insight from observation is that collaboration consists of fluid transitions between these patterns in the accomplishment of the design task, driven by a flexible process of subgrouping and regrouping which reflects the structure and progress of the task. Yet most collaborative virtual environment systems support only one pattern of collaboration—peer-to-peer—and those that do explicitly support multiple patterns or roles do not allow fluid transitions between them in the context of the same task. In addition, no explicit support is provided to allow subgroups to be formed and dissolved. A collaborative virtual environment that supports multiple collaboration patterns and fluid transitions was developed using the Shared Simple Virtual Environment (SSVE) application framework. A novel user interface widget, the collaboration tree, was created to drive the subgrouping and regrouping process. Group experiments were performed to test the operating hypothesis that support for group collaboration patterns led to higher performance. The result was that the operating hypothesis was confirmed; however, the conceptual approach to problem solving, suggested by the presence of support for collaboration patterns, may have been more significant than the actual mechanism provided.

Successes and Failures in Co-Present Situations

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.

Effects of Local-Lag Mechanism on Task Performance in a Desktop CVE System

Consistency maintenance is a kernel problem in Collaborative Virtual Environment (CVE) research. The approaches used in Networked Virtual Environments (e.g., DR algorithm) could not be used in CVEs, for they could not prevent short-term inconsistency. Therefore, local-lag mechanism has been proposed to eliminate short-term inconsistency in CVEs. Choosing a proper lag value is a key problem in local-lag mechanism. This paper studied the effects of lag value (0ms-900ms) on task performance in a desktop CVE system. Experimental results indicate that the effect of lag value on task performance is not linear. The effect could be separated into four segments by three dividing points: 150ms, 300ms and 600ms. Lag has no effect on task performance while ranging from 0ms to 150ms. From 150ms to 300ms, lag slightly affects task performance. Lag deteriorates task performance seriously while ranging from 300ms to 600ms. When lag is longer than 600ms, the task cannot be accomplished sometimes.

A Study of Event Traffic During the Shared Manipulation of Objects Within a Collaborative Virtual Environment

Event management must balance consistency and responsiveness above the requirements of shared object interaction within a Collaborative Virtual Environment (CVE) system. An understanding of the event traffic during collaborative tasks helps in the design of all aspects of a CVE system. The application, user activity, the display interface, and the network resources, all play a part in determining the characteristics of event management. Linked cubic displays lend themselves well to supporting natural social human communication between remote users. To allow users to communicate naturally and subconsciously, continuous and detailed tracking is necessary. This, however, is hard to balance with the real-time consistency constraints of general shared object interaction. This paper aims to explain these issues through a detailed examination of event traffic produced by a typical CVE, using both immersive and desktop displays, while supporting a variety of collaborative activities. We analyze event traffic during a highly collaborative task requiring various forms of shared object manipulation, including the concurrent manipulation of a shared object. Event sources are categorized and the influence of the form of object sharing as well as the display device interface are detailed. With the presented findings the paper wishes to aid the design of future systems.

Managing Collaboration in the nanoManipulator

We designed, developed, deployed, and evaluated the Collaborative nanoManipulator (CnM), a distributed, collaborative virtual environment system supporting remote scientific collaboration between users of the nanoManipulator interface to atomic force microscopes. This paper describes the entire collaboration system, but focuses on the shared nanoManipulator (nM) application. To be readily accepted by users, the shared nM application had to have the same high level of interactivity as the single-user system and include all the functions of the single-user system. In addition the application had to support a user's ability to interleave working privately and working collaboratively. Based on our experience developing the CnM, we present: a method of analyzing applications to characterize the concurrency requirements for sharing data between collaborating sites, examples of data structures that support distributed collaboration and interleaved private and collaborative work, and guidelines for selecting appropriate synchronization and concurrency control schemes.

Constructing a Gazebo: Supporting Teamwork in a Tightly Coupled, Distributed Task in Virtual Reality

Many tasks require teamwork. Team members may work concurrently, but there must be some occasions of coming together. Collaborative virtual environments (CVEs) allow distributed teams to come together across distance to share a task. Studies of CVE systems have tended to focus on the sense of presence or copresence with other people. They have avoided studying close interaction between us-ers, such as the shared manipulation of objects, because CVEs suffer from inherent network delays and often have cumbersome user interfaces. Little is known about the ef-fectiveness of collaboration in tasks requiring various forms of object sharing and, in particular, the concurrent manipu-lation of objects. This paper investigates the effectiveness of supporting teamwork among a geographically distributed group in a task that requires the shared manipulation of objects. To complete the task, users must share objects through con-current manipulation of both the same and distinct at-tributes. The effectiveness of teamwork is measured in terms of time taken to achieve each step, as well as the impression of users. The effect of interface is examined by comparing various combinations of walk-in cubic immersive projection technology (IPT) displays and desktop devices.

Small group behaviour experiments in the Coven project

The Collaborative Virtual Environments (Coven) project, a four-year European project launched in October 1995, designs and explores collaborative virtual environment (CVE) technology. It aims to investigate the feasibility of scalable CVE worlds through developing CVE systems and demonstrating prototype applications in a virtual travel rehearsal scenario. Our experiments in collaborative virtual environments investigated group behavior issues such as relationships between emergent leadership and computational resources, and the sense of presence and copresence among participants.