An empirical evaluation of textual display configurations for supervisory tasks

There is often a need to display logged information textually for real-time event-based supervisory tasks. Textual display design can follow several directions that reflect a tradeoff between a visual load and an operational load. The study reported here was designed in order to examine this tradeoff and its implications for such display design. An event-based monitoring and handling task was used with different event types having either a high or a low handling priority. The events were presented in four different display configurations varying in their degree of visual and operational load. The specific performance indices were event dwelling times, event handling proportion, and handling errors. In general it was found that the high priority events were handled faster and more accurately than the low priority events. In addition, performance with the various display configurations was dependent upon event type. These findings are discussed in terms of visual vs. operational load tradeoff and its context-sensitivity. Some implications for display design and further research on event presentation approaches are discussed.     

An empirical evaluation of textual display configurations for supervisory tasks

There is often a need to display logged information textually for real-time event-based supervisory tasks. Textual display design can follow several directions that reflect a tradeoff between a visual load and an operational load. The study reported here was designed in order to examine this tradeoff and its implications for such display design. An event-based monitoring and handling task was used with different event types having either a high or a low handling priority. The events were presented in four different display configurations varying in their degree of visual and operational load. The specific performance indices were event dwelling times, event handling proportion, and handling errors. In general it was found that the high priority events were handled faster and more accurately than the low priority events. In addition, performance with the various display configurations was dependent upon event type. These findings are discussed in terms of visual vs. operational load tradeoff and its context-sensitivity. Some implications for display design and further research on event presentation approaches are discussed.     

Effects of virtual environment platforms on emotional responses

The goal of the current study was to investigate the effects of different virtual environment (VE) technologies (i.e., desktop, head mounted display, or fully immersive platforms) on emotional arousal and task performance. Fifty-three participants were recruited from a college population. Reactivity to stressful VEs was examined in three VE systems from desktop to high-end fully immersive systems. The experiment was a 3 (desktop system, head mounted display, and six wall system) × 2 (high- and low-stressful VE) within subject design, with self-reported emotional arousal and valence, skin conductance, task performance, presence, and simulator sickness examined as dependent variables. Replicating previous studies, the fully immersive system induced the highest sense of presence and the head mounted display system elicited the highest amount of simulator sickness. Extending previous studies, the results demonstrated that VE platforms were associated with different patterns in emotional responses and task performance. Our findings suggest that different VE systems may be appropriate for different scientific purposes when studying stress reactivity using emotionally evocative tasks.     

A maritime navigation display that provides visual feedback to improve conning officers' ship-handling during low visibility environments

Navigating a ship at night in close proximity to another vessel is a dangerous task. To improve conning officers' night time ship-handling performance, a visual navigation display is proposed that is mounted on the stern of the aircraft carrier that will help shipboard conning officers manoeuvre in a battle group formation. To test the effectiveness of the visual navigation display, the Nimitz-class aircraft and plane guard vessel, a Ticonderoga-class cruiser, were modelled in a virtual environment. A navigation display condition had significantly fewer navigational positional errors than a non-navigation display condition. The navigation display provided immediate feedback as to whether the aircraft carrier had changed bearing or speed, thus enabling the operator to initiate the appropriate input to maintain station astern of the carrier. Actual or potential applications of this research include the deployment of a maritime navigation display to assist conning officers' ship handling.     

A maritime navigation display that provides visual feedback to improve conning officers' ship-handling during low visibility environments

Navigating a ship at night in close proximity to another vessel is a dangerous task. To improve conning officers' night time ship-handling performance, a visual navigation display is proposed that is mounted on the stern of the aircraft carrier that will help shipboard conning officers manoeuvre in a battle group formation. To test the effectiveness of the visual navigation display, the Nimitz-class aircraft and plane guard vessel, a Ticonderoga-class cruiser, were modelled in a virtual environment. A navigation display condition had significantly fewer navigational positional errors than a non-navigation display condition. The navigation display provided immediate feedback as to whether the aircraft carrier had changed bearing or speed, thus enabling the operator to initiate the appropriate input to maintain station astern of the carrier. Actual or potential applications of this research include the deployment of a maritime navigation display to assist conning officers' ship handling.     

Proposal of an Index to Evaluate Visual Fatigue Induced During Visual Display Terminal Tasks

The study described in this article was designed to evaluate visual fatigue induced during video display terminal (VDT) tasks. Newly developed equipment was used that can simultaneously measure pupillary change, focal accommodation, and eye movement. The changes in these 3 physiological measures, taken during a VDT task, were used to propose an index for evaluating visual fatigue. Through multiple regression analysis, an index to describe the psychological sense of visual fatigue was obtained. In this index, the minimum pupil diameter, velocity of focal accommodation for constriction, and width of focal accommodation were included. The results suggest that visual fatigue in VDT tasks can be evaluated effectively using both pupil diameter and focal accommodation. The index can be used to assess visual fatigue induced during a VDT task if the following 3 conditions are satisfied:

1. Head movement is limited and infrequent.

2. The task requires focal accommodation.

3. During the task, there is no outstanding change in the lighting environment such as luminous intensity or brightness.     

Comparing speech versus text displays for alarm handling

The rise of computers in command and control domains has meant that control operations can be performed via desk-based visual display terminals. This trend has also produced the potential to display information to operators in a variety of formats. Of particular interest has been the use of text-based displays for alarm presentation. There are possible limitations to the use of text for alarm presentation, not least of which is the need for a dedicated alarms display screen (or, at least, a display page). Given the capability of computers to synthesize speech, it is possible that speech-based alarms could generate the same information as text-based displays without the need for dedicated screen space. In this paper an experimental comparison of speech-based and text-based displays for presentation of alarms is reported. The findings show that speech leads to longer response times than text displays, but that it has minimal effect on the efficacy of fault handling. The results are discussed within the alarm initiated activities framework and implications for alarm system design are outlined.     

Operator orientation and compatibility in visual-motor task performance

This experiment assessed three alternative forms of directional compatibility between control and display movement, to examine their degree of dependence on the orientation of the operator. Subjects performed a target acquisition task in each of 11 conditions which embodied the three compatibility types alone or in combination. Visual-motor (VM) compatibility was defined as display movement in a given direction in the subject's visual field produced by control movement in the same direction in the subject's 'virtual' visual field (i.e., were he or she looking at the control rather than the display). Control-display (CD) compatibility referred to congruence between control and display movements. Visual-trunk (VT) compatibility was present if a control movement was in the same direction relative to the operator's trunk as the movement of the display in the visual field. VM compatibility produced performance superior to that under CD or VT compatible conditions in all phases of the task, and was independent of the subject's physical orientation and of the target direction. Visual-motor compatibility appears to reflect a basic and general relationship between visual and motor codes in the central nervous system, and may prove a useful basis for reducing errors and enhancing performance in certain human-machine systems.     

How information within the perceptual span guides visual search and aids perception

We explore the guiding effect of task-related information appearing within the perceptual span on visual search based on elements such as the range of effective information attention within the perceptual span and the orientation of task-related objects. In the first experiment, we recorded reaction time and eye movement data of 48 subjects performing a visual search task for target information in the navigation interface and divided them into four experimental groups according to the perceptual span (within or outside the range) and orientation (left or right) of the task-related information. The experimental results showed that: (a) task-related information appearing within the perceptual span had a guiding effect on target search; and (b) the right side closer to the target in task search have better performance in guiding. In the second experiment, eye-movement experiments of the navigation interface based on the eye-movement processing theoretical model of linguistics showed that: (a) within the perceptual span, the shifting of attention causing eye movements (saccade) and brings gaze into the area of interest, and (b) the perceptual span moves with attention shifts. This study provides evidence for cognitive processing of information responses within the perceptual span and dynamic adjustment of perceptual span location and provides a reliable method for effective information presentation and visual layout in navigation interfaces, with a view to providing reference and learning for related studies.     

Divided attention in experienced young and older drivers: lane tracking and visual analysis in a dynamic driving simulator.

A simulated driving task that required the simultaneous execution of two continuous visual tasks was administered to 12 healthy young (mean age 26.1 years) and 12 healthy older (mean age 64.4 years) experienced and currently active drivers. The first task was a compensatory lane-tracking task involving a three-dimensional road display. The second task was a timed, self-paced visual analysis task involving either a vocal or manual binary response to dot patterns projected within the road display. Using adaptive tasks, single-task difficulty was individually adjusted for each subject. To control for individual differences in attention allocation strategy, the dual task was performed according to three different sets of instructions based on the relative importance of each task. Compared with young adults, older adults showed a significantly decreased ability to divide attention. This effect was apparent in lane tracking and in the accuracy of visual analysis. The impairment of divided attention was less pronounced in the vocal condition than in the manual one. This suggests that difficulty in integrating responses may be an important determinant of poor dual-task performance in old age.     

A model for experience-dependent changes in the responses of inferotemporal neurons

Neurons in inferior temporal (IT) cortex exhibit selectivity for complex visual stimuli and can maintain activity during the delay following the presentation of a stimulus in delayed match to sample tasks. Experimental work in awake monkeys has shown that the responses of IT neurons decline during presentation of stimuli which have been seen recently (within the past few seconds). In addition, experiments have found that the responses of IT neurons to visual stimuli also decline as the stimuli become familiar, independent of recency. Here a biologically based neural network simulation is used to model these effects primarily through two processes. The recency effects are caused by adaptation due to a calcium-dependent potassium current, and the familiarity effects are caused by competitive self-organization of modifiable feedforward synapses terminating on IT cortex neurons.     

Assessing situation awareness in multitasking supervisory control using success rate of self-terminating search

The purpose of this study is to investigate measuring situation awareness (SA) by using the success rate of self-terminating visual search (STVS) in a multitasking supervisory control environment. Currently, many researchers have focused on developing unobtrusive SA metrics in a multitasking environment. Although some of the advanced eye-tracking metrics can estimate the operator's SA during a task, certain methodological issues remain for measuring SA in a supervisory control and multitasking environment. In this study, participants performed a distributed control task with the multi-attribute task battery. To measure the participant's SA, situation awareness global assessment technique (SAGAT) was used during the experiment. SA performance was compared to the success rate of STVS. An eye-head integrated tracking system was used to measure the rate of STVS based on the participants' eye movements and head positions in different monitoring conditions. The results showed that task-switching activity was influenced by salient features in a display. It causes a significant difference on SA between different monitoring conditions, and the difference is also monitored in the success rate of STVS. Furthermore, the study found that the attention level in visual searching influences situational awareness in a supervisory control environment. The findings from this study suggest that the success rate of STVS could be used as a new metric for measuring SA related to the visual perception of the elements in a multitasking supervisory control environment.     

A novel paradigm for patient-cooperative control of upper-limb rehabilitation robots

Early intervention and intensive therapy improve the outcome of neuromuscular rehabilitation. There are indications that where a patient is motivated and premeditates their movement, the recovery is more effective. Therefore, a strategy for patient-cooperative control of rehabilitation devices for upper extremities is proposed and evaluated. The strategy is based on the minimal intervention principle allowing an efficient exploitation of task space redundancies and resulting in user-driven movement trajectories. The patient's effort is taken into consideration by enabling the machine to comply with forces exerted by the user. The interaction is enhanced through a multimodal display and a virtually generated environment that includes haptic, visual and sound modalities.     

基于xml的实时战场环境仿真

针对传统军事演练仿真实验中,一次试验只能仿真一种战场环境的情况。提出了一种实时战场环境仿真方法,该方法采用分布式仿真技术,将系统分为任务端与视景仿真端,任务端负责作战任务的生成,视景仿真端负责战场环境的创建和显示;通过xml文件将任务端作战任务下达给视景仿真端,视景仿真端根据xml解析内容动态生成战场环境,并显示仿真效果,解决了系统的配置问题和实时性显示问题。采用该方法生成的二维或三维战场环境,能随仿真试验要求的改变而改变,无需重新编译,实现多次仿真试验,提高仿真效率。通过仿真表明了该方法的有效性。     

Attentional models of multitask pilot performance using advanced display technology

In the first part of the reported research, 12 instrument-rated pilots flew a high-fidelity simulation, in which air traffic control presentation of auditory (voice) information regarding traffic and flight parameters was compared with advanced display technology presentation of equivalent information regarding traffic (cockpit display of traffic information) and flight parameters (data link display). Redundant combinations were also examined while pilots flew the aircraft simulation, monitored for outside traffic, and read back communications messages. The data suggested a modest cost for visual presentation over auditory presentation, a cost mediated by head-down visual scanning, and no benefit for redundant presentation. The effects in Part 1 were modeled by multiple-resource and preemption models of divided attention. In the second part of the research, visual scanning in all conditions was fit by an expected value model of selective attention derived from a previous experiment. This model accounted for 94% of the variance in the scanning data and 90% of the variance in a second validation experiment. Actual or potential applications of this research include guidance on choosing the appropriate modality for presenting in-cockpit information and understanding task strategies induced by introducing new aviation technology.     

Tracking and discrete dual task performance with different spatial stimulus–response mappings

The effect of spatial compatibility on dual-task performance for various display–control configurations was studied using a tracking task and a discrete four-choice response task. A total of 36 participants took part in this study, and they were asked to perform the primary tracking task while at the same time to respond to an occasional signal. Different levels of compatibility between the stimuli and responses of the discrete response task were found to lead to different degrees of influence on the tracking task. However, degradation of performance was observed for both tasks, which was probably due to resource competition for the visual and spatial resources required for simultaneous task operation and required for bimanual responses. No right–left prevalence effect for the spatial compatibility task was observed in this study, implying that the use of unimanual two-finger responses may not provide the right conditions for a significant effect in the horizontal right–left dimension.

Practitioner Summary: The effect of spatial compatibility in multiple display–control configurations was examined in a dual-task paradigm. The analyses of keen competition for visual and spatial resources in processing the dual tasks under different degrees of stimulus–response compatibility provide useful ergonomics design implications and recommendations for visual interfaces requiring frequent visual scanning.     

作战标号颜色与几何视觉编码融合显示技术

针对作战装备及野外战场环境的信息呈现,基于作战标号颜色与几何视觉编码的融合显示技术,提出一种对颜色军事语义通过几何辅助进行强化表征的方法,采用贝塞尔曲线对作战标号进行视觉优化处理；设计了“矩形+贝赛尔曲线”的融合显示样式,对作战标号的可视化方式进行研究,使显示样式具有较好的光滑性、视觉分离等效果；增强了作战标号的军事表达能力与人机交互功能,该设计能较好地提升战场态势的信息呈现水平。     

The effects of multifocal refractive lenses on occipital extension and forward head posture during a visual task

The purpose of this study was to determine if a change in forward head posture and occipital extension occurred in participants who wore multifocal lenses vs. those persons with non-multifocal lenses while performing an 8-min visual reading task on a visual display unit (VDU). Forty-two healthy human participants were recruited for this study. Thirty-three participants completed the study. Fourteen participants wore multifocal lenses and 19 wore frames with non-multifocal lenses. To evaluate the degree of change of forward head posture and occipital extension digital photographs of cervical posture were taken at four different time intervals: prior to performing the reading task and at 3, 5 and 8 min during the reading task. The digital photographs were analysed utilizing a computer program. Two one-way ANOVA were utilized to determine the degree of change of forward head posture and occipital extension between groups. A significant difference was identified between groups for changes in degrees of forward head posture while performing a visual reading task on a VDU. However, no significant difference between groups was found for occipital extension while performing the same task. Multifocal wearers exhibit greater degrees of change in forward head posture and occipital extension than non-multifocal wearers. These postural changes may place them at a greater risk for musculoskeletal disorders and headaches.     

Eye symptoms and reading abilities of computer users subjected to visually impaired direct glare

Computer work is a visually demanding task associated with adverse eye symptoms. Frequent use of digital displays is known to cause a deterioration of the so-called binocular control. Direct glare further reduces the capacity for binocular coordination during computer work, leading to reduced reading ability and increased eye symptoms.The purpose of this study was to investigate the effect of different luminance levels of direct glare on binocular eye movement control and reading ability in a computer work environment.Sixteen participants with normal binocular vision performed equal reading tasks in a balanced study. Three controlled lighting conditions of direct glare (2000, 4000 and 6000 cd/m²) were tested, in addition to no glare. After each trial, the participants answered survey questionnaires regarding their understanding of the text, as well as their subjective experience of workload and perceived vision. Horizontal fixation disparity (FD) was measured before and after the reading tasks to evaluate binocular eye movement control.When comparing the responses of visual experience, a significant difference in reported eye symptoms was found between lighting conditions. Based on the variation (SD), a significant difference was found within mean values of repeated measurements of horizontal FD and a significantly higher variation in a comparison of initial FD values measured during lighting conditions of no glare, to final measured values in all three glare conditions. Reading ability was found to be significantly negative affected with the adversity of lighting conditions.This study supports the contention that binocular eye movement control is reduced caused by direct glare. Even lower degree of disability glare caused eye symptoms. The results establish the argument that working with flat screens raises visual demands.     

Control-display mapping in brain-computer interfaces

Event-related potential (ERP) based brain-computer interfaces (BCIs) employ differences in brain responses to attended and ignored stimuli. When using a tactile ERP-BCI for navigation, mapping is required between navigation directions on a visual display and unambiguously corresponding tactile stimuli (tactors) from a tactile control device: control-display mapping (CDM). We investigated the effect of congruent (both display and control horizontal or both vertical) and incongruent (vertical display, horizontal control) CDMs on task performance, the ERP and potential BCI performance. Ten participants attended to a target (determined via CDM), in a stream of sequentially vibrating tactors. We show that congruent CDM yields best task performance, enhanced the P300 and results in increased estimated BCI performance. This suggests a reduced availability of attentional resources when operating an ERP-BCI with incongruent CDM. Additionally, we found an enhanced N2 for incongruent CDM, which indicates a conflict between visual display and tactile control orientations. PRACTITIONER SUMMARY: Incongruency in control-display mapping reduces task performance. In this study, brain responses, task and system performance are related to (in)congruent mapping of command options and the corresponding stimuli in a brain-computer interface (BCI). Directional congruency reduces task errors, increases available attentional resources, improves BCI performance and thus facilitates human-computer interaction.