Virtual environments and ergonomics: needs and opportunities

Although based on a still immature technology, virtual environments appear to have potential for applications in industry, commerce, medicine and education. The role of ergonomics will be in development of improved virtual environment interfaces and in enabling better utilization of the technology through specifying user needs and requirements and developing evaluation methodologies. By extension, ergonomists will also be involved in building virtual environments for use in areas of ergonomics activity such as workplace layout, interface design, procedures testing, education and training. This paper overviews virtual environment attributes and capabilities and proposes a framework for their specification, development and evaluation, before summarizing current ergonomics research issues. Current work on participant side effects is summarized. A strong case is made for the potential value of ergonomics for virtual environments and vice versa.     

Measurement of presence and its consequences in virtual environments

A sense of presence is one of the critical components required by any effective virtual environment (VE). In contrast, side effects such as sickness may be produced in some virtual environments, detracting from the enjoyment or usefulness of the VE and from subsequent performance of the participant. Both presence and sickness in virtual environments are multifactorial phenomena not easily amenable to understanding or measurement. The first experiment reported here compares use of direct performance measures and rating scales to assess presence, whilst varying the VE display medium (head mounted and desktop displays) and whether or not sound was used in the VE. The second experiment addresses associations between presence, sickness and enjoyment of virtual environment participation. There was enough comparability between a reflex response within the VE and the rating scales to justify future exploration of the former measure of presence. A number of explanations are given for the partial association found between presence and sickness.     

Integration of manufacturing services into virtual environments over the internet

Virtual reality (VR) is a rapidly developing technology that has a wide spectrum of industrial and commercial applications. Networked (distributed or shared) virtual environments (VE) are of growing interest to modern manufacturing industry; a dominating use of networked virtual manufacturing environments (VMEs) is on-line visualisation and collaborative control of 3D information. This has to be supported by real-time data transfer. To meet a broad range of common requirements for Internet-based VE communications, particularly for virtual manufacturing and collaborative design and control, this paper presents a networked virtual environment system that is designed to support networked virtual design and manufacturing. The system is implemented with manufacturing message specification (MMS) standards so as to integrate a range of manufacturing services into networked VEs over the Internet.     

Interaction styles in tools for developing virtual environments

This article discusses and compares interaction styles in development tools for virtual environments (VE). The comparison relies on a qualitative empirical study of two development processes where a command language and a direct manipulation based tool were used to develop the same virtual environment application. The command language tool proved very flexible and facilitated an even distribution of effort and progress over time, but debugging and identification of errors was very difficult. Contrasting this, the direct manipulation tool enabled faster implementation of a first prototype but did not facilitate a shorter implementation process as a whole. On the basis of these findings, the strength and weaknesses of direct manipulation for developing virtual environment applications are explored further through a comparison with a successful direct manipulation tool for developing interactive multimedia applications. The comparisons are used to identify and emphasize key requirements for virtual environment development tool interface design.     

A hierarchical framework for visualising and simulating supply chains in virtual environments

This paper presents research into applying virtual environment (VE) technology to supply chain management (SCM). Our research work has employed virtual manufacturing environments to represent supply chain nodes to simulate processes and activities in supply chain management. This will enable those who are involved in these processes and activities to gain an intuitive understanding of them, so as to design robust supply chains and make correct decisions at the right time. A framework system and its hierarchical structure for visualising and simulating supply chains in virtual environments are reported and detailed in this paper.     

一个基于Web的网络虚拟现实系统的设计与实现

虚拟现实技术发展很快，有广泛的工业和商业应用。网络虚拟现实技术已越来越为工业制造业所关注，虚拟制造环境(VME)的一个主要用途是在线可视化和对3D信息的协作控制，这需要实时数据传输的支持。为了满足基于Internet的VE通信需求，特别是为满足虚拟制造和协作设计和控制，该文设计并实现了一个支持网络虚拟设计和制造的网络虚拟现实系统，此系统用MMS协议实现VE通信，并将工业控制服务集成于基于Internet的虚拟环境中。     

Visual Realism Enhances Realistic Response in an Immersive Virtual Environment

Does greater visual realism induce greater participant presence in immersive virtual environments (VE)? Presence refers to how realistically participants respond to the environment as well as their subjective sense of being in the place depicted by the VE. Thirty-three people were exposed for three minutes to a virtual environment depicting a precipice using a head-tracked head-mounted display system. Seventeen of them saw the environment rendered with real-time recursive ray tracing (RT) that included shadows and reflections of their virtual body, and the remainder experienced the same environment rendered with ray casting (RC), which did not include shadows and reflections. Participants completed a presence questionnaire immediately after their experience, and physiological responses (skin conductance and electrocardiogram) were recorded throughout. Results show that subjective presence was higher for the RT environment than for the RC one and that higher stress was induced in the RT environment compared to the RC one.     

Measurement of postural stability before and after immersion in a virtual environment

Research into the effects of simulators has led to suggestions that postural instability occurring after immersion in a virtual reality virtual environment (VR/VE) may have direct implications for the safety of post-immersion activities such as driving or operating machinery. However, experimental studies have highlighted a lack of standardisation in the postural stability measurement techniques applied and subsequent inconsistencies in the results obtained. An experiment was conducted to evaluate the use of static, dynamic and posturographic postural stability measures in determining the effect of participation in an interactive virtual environment (VE) for 20 min. The results demonstrate differences in the sensitivity of postural stability measurement techniques and variations in inter- and intra-individual responses to measures. The VE immersion was found to produce postural instability only when measured using a posturographic technique under normal stance static posture, and then only mildly and not long-lasting. No associations were found between reported symptoms of simulator sickness and postural stability with postural stability measures. This paper discusses issues relating to postural stability measurement and the implications for evaluation of virtual environment effects.     

Performing ergonomics analyses through virtual interactive design: Validity and reliability assessment

Virtual interactive design methodology was initially proposed as an integrated environment for digital human model–based ergonomics analysis of human–machine interactions, which uses a motion capture system and virtual environment to realize task simulation. The validity and reliability of this analysis methodology has not been systematically studied. In this article, potential errors are first investigated based on the technology used in the system structure and work process; then, three experimental integration levels are proposed to use different resources for creating manikin postures. Validity and reliability to use this integrated environment for static ergonomics analysis are then assessed by comparing the ergonomics analysis outputs achieved based on the three integration levels. The results indicate that the reliability of this methodology is good; however, the validity of the integrated system is affected by the limitation of the virtual environment used in the testing. © 2011 Wiley Periodicals, Inc.     

An ethnographic, action-based approach to human experience in virtual environments

This paper addresses a sensitive issue, of presence experienced by people interacting with a virtual environment (VE). Understanding ‘presence’, both theoretically and empirically, is important for designers interested in building effective computer-mediated environments for learning and work activities. The concept of presence has been treated mostly as a state of mind, to be investigated through ‘objective’ and ‘subjective’ measurement devices. The authors propose to add a different approach, which can address presence as an action-based process. This approach considers presence as the ongoing result of the actions performed in an environment and the local and cultural resources deployed by actors. In this sense, ‘presence’ can be captured by monitoring the sequence of participants’ actions and the aspects of the environment that are involved in this process; discourse/interaction analysis represents a fitting method for this goal. Sequences of interaction with a virtual library are used to illustrate some core aspects of an ethnographic, action-based approach to presence, such as the action possibilities envisaged by participants, the configuration of the virtual objects, the norms that regulate the interaction, the resources that are imported in the VE. These aspects are a necessary step to understand users’ presence in the VE and to plan consequent interventions to ameliorate the design of the interface.     

Enhancing virtual environment spatial awareness training and transfer through tactile and vestibular cues

Haptic interaction has been successfully incorporated into a variety of virtual environment (VE) systems, yet designing multimodal VE training systems remains challenging as each cue incorporated during training should maximise learning and training transfer. This study examined the impact of incorporating two independent, spatialised tactile cues and vestibular cues into a military VE training environment with the goal of empirically examining whether such cues could enhance performance within the training environment and also that knowledge and skills gained during training could transfer to another environment. The results showed that tactile cues enhanced spatial awareness and performance during both repeated training and within a transfer environment, yet there were costs associated when two independent tactile cues were presented during training. In addition, results suggest that spatial awareness benefits from a tactile point indicator may be impacted by vestibular cues, as performance benefits were seen when tactile cues were paired with head tracking. To fully realise training potential, it is essential to determine how best to leverage multimodal capacity of VE training systems by identifying how multimodal training cues may advance knowledge, skills and attitudes of trainees. Results from this study provide design guidelines for incorporating tactile cues in VE training environments to enhance spatial awareness.     

Creating Real-Time Embodied Autonomous Agents

A challenging research area for computer graphics and virtual environments (VE) is training interpersonal interactions. In such a system, at least one person is the VE participant, while several more virtual human agents (represented by human-like, embodied models) are engaged in activities in the same virtual space. The participants, whether live or virtual, should interact as if all were real. This means that the virtual agents must have several characteristics afforded to real people, including the following:     

Interaction with a desktop virtual environment: a 2D view into a 3D world

With the development of computer software and hardware in the past few years, it has been possible to produce effective training virtual environments on everyday personal computers with little expert training required for users or designers. However, the development of the equipment that enables this has brought little coinciding research on what features to include when designing these environments. Despite these increased advances in PC capabilities for desktop virtual environments (VEs), there are still limitations on the number of objects that can be programmed to be interactive, usually due to restrictions on programming time and cost. As a result, it is often left to the programmer to decide which of the objects included to increase the realism of the environment will be interactive and which aesthetic. The work presented in this paper is an experiment that aims to establish a guide for environment designers to aid effective environment interaction development by identifying key elements in a VE design.

Physical ergonomics of virtual environment use

This paper describes an investigation of the types of problems that may be experienced by Virtual Reality (VR) users. Initial concerns have been voiced about various issues concerning the design of VR equipment, particularly the physical ergonomics of head-mounted displays (HMDs) and hand-held input devices, and the problems associated with display resolution and lags. This study investigated a number of VR users' perceptions of the types of physical ergonomics issues that they were aware of when participating in a number of different virtual environments (VEs), using different VR systems. Several different methods were employed, including questionnaires, body mapping, user observation and interviews. Issues highlighted as either causing participants discomfort or interfering with their experience of the VE were: discomfort from static posture requirements, general discomfort from wearing the HMD, difficulty becoming accustomed to 3D hand held input devices, dissatisfaction with deficits in the visual display and fear of getting 'tangled' in connecting cables. The implications of these findings for developers, implementers and users of VR are discussed.     

Fatigue evaluation in maintenance and assembly operations by digital human simulation in virtual environment

Virtual human techniques have been used a lot in industrial design in order to consider human factors and ergonomics as early as possible, and it has been integrated into VR applications to complete ergonomic evaluation tasks. In order to generalize the evaluation task in VE, especially for physical fatigue evaluation, we integrated a new fatigue model into a virtual environment platform. Virtual Human Status is proposed in this paper in order to assess the difficulty of manual handling operations, especially from the physical perspective. The decrease of the physical capacity before and after an operation is used as an index to indicate the difficulty level. The reduction of physical strength is simulated in a theoretical approach on the basis of a fatigue model in which fatigue resistances of different muscle groups were regressed from 24 existing maximum endurance time models. A framework based on digital human modeling technique is established to realize the comparison of physical status. An assembly case in airplane assembly is simulated and analyzed under the framework in VRHIT experiment platform. The endurance time and the decrease of the joint moment strengths are simulated. The experimental result in simulated operations under laboratory conditions confirms the feasibility of the theoretical approach: integration of virtual human simulation into virtual reality for physical fatigue evaluation.     

The virtual playground: an educational virtual reality environment for evaluating interactivity and conceptual learning

The research presented in this paper aims at investigating user interaction in immersive virtual learning environments, focusing on the role and the effect of interactivity on conceptual learning. The goal has been to examine if the learning of young users improves through interacting in (i.e. exploring, reacting to, and acting upon) an immersive virtual environment (VE) compared to non-interactive or non-immersive environments. Empirical work was carried out with more than 55 primary school students between the ages of 8 and 12, in different between-group experiments: an exploratory study, a pilot study, and a large-scale experiment. The latter was conducted in a virtual environment designed to simulate a playground. In this “Virtual Playground,” each participant was asked to complete a set of tasks designed to address arithmetical “fractions” problems. Three different conditions, two experimental virtual reality (VR) conditions and a non-VR condition, that varied the levels of activity and interactivity, were designed to evaluate how children accomplish the various tasks. Pre-tests, post-tests, interviews, video, audio, and log files were collected for each participant, and analysed both quantitatively and qualitatively. This paper presents a selection of case studies extracted from the qualitative analysis, which illustrate the variety of approaches taken by children in the VEs in response to visual cues and system feedback. Results suggest that the fully interactive VE aided children in problem solving but did not provide a strong evidence of conceptual change as expected; rather, it was the passive VR environment, where activity was guided by a virtual robot, that seemed to support student reflection and recall, leading to indications of conceptual change.     

Using virtual environments to train firefighters

Using virtual environments for training and mission rehearsal gives US Navy firefighters an edge in fighting real fires. A test run on the ex-USS Shadwell measured the improvement. The results suggest that virtual environments serve effectively for training and mission rehearsal for shipboard firefighting. VE training provides a flexible environment where a firefighter can not only learn an unfamiliar part of the ship, but also practice tactics and procedures for fighting a fire by interacting with simulated smoke and fire without risking lives or property. These tests proved a successful first step in developing a new training technology for shipboard firefighting based on immersive virtual environments. The tests also indicated potential areas for improvement, requiring additional research. User interaction techniques for manipulating objects in VEs need further study, along with usability studies to determine their effectiveness or utility. Other areas that could enhance VE training systems include more natural and intuitive I/O devices such as 3D sound, speech and natural language input, integrated multimedia and hypermedia instruction, and multi user interaction     

Perceiving affordances in virtual reality: influence of person and environmental properties in perception of standing on virtual grounds

We evaluated the perception of affordances in virtual environments (VE). In our work, we considered the affordances for standing on a virtual slanted surface. Participants were asked to judge whether a virtual slanted surface supported upright stance. The objective was to evaluate whether this perception was possible in virtual reality (VR) and comparable to previous works conducted in real environments. We found that the perception of affordances for standing on a slanted surface in virtual reality is possible and comparable (with an underestimation) to previous studies conducted in real environments. We also found that participants were able to extract and to use virtual information about friction in order to judge whether a slanted surface supported an upright stance. Finally, results revealed that the person’s position on the slanted surface is involved in the perception of affordances for standing on virtual grounds. Taken together, our results show quantitatively that the perception of affordances can be effective in virtual environments and influenced by both environmental and person properties. Such a perceptual evaluation of affordances in VR could guide VE designers to improve their designs and to better understand the effect of these designs on VE users.     

Manufacturing enterprise collaboration based on a goal-oriented fuzzy trust evaluation model in a virtual enterprise

To cope with the rapidly changing manufacturing environment, enterprise collaboration is getting increasingly more attention than ever before. The virtual enterprise (VE) is a concept that supports temporary alliances of manufacturing enterprises that have various collaboration models, such as extended enterprise, networked enterprise, concurrent enterprise, etc. Selection of trustworthy partners and trust building are important in virtual domains because they have largely been affecting the success of a VE. However, because of its complexity of trust, trust models in the literature are limited in their ability to cope with dynamic and virtual environment. In this paper, we propose a trust evaluation method of supporting enterprise collaboration and maximizing the satisfaction of cooperation. In this context, trust means the goal achievement probability. Trust value of an enterprise can be obtained by a fuzzy inference system whose rule-base is based on the top-level goal of a VE. According to the selector’s preference, various rules can be applied to trust evaluation. For further study, the planning and scheduling problems should be considered along with the trust-based partner selection for collaboration among manufacturing enterprises.     

Evaluation of Internal and External Validity of a Virtual Environment for Learning a Long Procedure

Virtual reality is a frequently used tool in vocational training. Nevertheless, its efficiency has not been systematically tested. The main goal of this study is to assess the effectiveness of a virtual environment (VE) for learning a complex procedure in the biomedical domain. Two experiments were performed. The first one assessed internal validity of the VE, which is the effectiveness of using a VE in the process of learning a new procedure. The second one tested external validity of the VE, which is the participants’ ability to reproduce the acquired skills in a real context. We find that internal and external validity must be evaluated before using a virtual environment in long-term procedure learning. The results of such evaluations are a basis for future experiments aiming to optimize learning conditions in a VE and transferring the acquired skills in a real context.