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T B Sheridan

Publications and source records attributed to T B Sheridan.

8 recordsLinked to original sources

A model for types and levels of human interaction with automation.

Technical developments in computer hardware and software now make it possible to introduce automation into virtually all aspects of human-machine systems. Given these technical capabilities, which system functions should be automated and to what extent? We outline a model for types and levels of automation that provides a framework and an objective basis for making such choices. Appropriate selection is important because automation does not merely supplant but changes human activity and can impose new coordination demands on the human operator. We propose that automation can be applied to four broad classes of functions: 1) information acquisition; 2) information analysis; 3) decision and action selection; and 4) action implementation. Within each of these types, automation can be applied across a continuum of levels from low to high, i.e., from fully manual to fully automatic. A particular system can involve automation of all four types at different levels. The human performance consequences of particular types and levels of automation constitute primary evaluative criteria for automation design using our model. Secondary evaluative criteria include automation reliability and the costs of decision/action consequences, among others. Examples of recommended types and levels of automation are provided to illustrate the application of the model to automation design.

Automation↗

Human versus automation in responding to failures: an expected-value analysis.

A simple analytical criterion is provided for deciding whether a human or automation is best for a failure detection task. The method is based on expected-value decision theory in much the same way as is signal detection. It requires specification of the probabilities of misses (false negatives) and false alarms (false positives) for both human and automation being considered, as well as factors independent of the choice--namely, costs and benefits of incorrect and correct decisions as well as the prior probability of failure. The method can also serve as a basis for comparing different modes of automation. Some limiting cases of application are discussed, as are some decision criteria other than expected value. Actual or potential applications include the design and evaluation of any system in which either humans or automation are being considered.

Automation↗

Human factors in telesurgery: effects of time delay and asynchrony in video and control feedback with local manipulative assistance.

This paper presents the results of experiments examining the performance of a telesurgeon and an assistant local to the patient performing simulated laparoscopic tasks under a variety of time-delay conditions. Of particular interest is a comparison between the surgeon provided with audio/video and force feedbck synchronously with various time delays, and the surgeon performing asynchronously, where video is delayed relative to force feedback. These conditions are relevant since current telecommunication systems have limited bandwidth, and video signals must be compressed for efficient transmission. This produces a time lag between the video camera and the surgeon's monitor, Force feedback and position commands from a surgical teleoperator require much lower bandwidth, and can be transmitted in near-real time. In the first of two series of experiments, two laparoscopic training tasks were performed under different time-delay conditions, with force and video feedback delayed by equal amounts. In the second series, using the same tasks, the force feedback was more immediate, while the video delay lagged by the time required for compression and decompression. In both experiments, there were various role assignments in terms of whether the telesurgeon or the assistant controlled the laparoscope and/or the various surgical tools required. The three most striking results are that (1) nontrivial time delays significantly degraded the performance of the surgical tasks, (2) asynchronous force feedback resulted in significantly faster task-performance than did synchronous performance when the surgeon operated the laparoscopic tools, and (3) there was no difference between synchrony and asynchrony when the remote surgeon operated the laparoscope and gave commands while the local assistant operated the surgical tools.

Humans↗

Teleoperator performance with varying force and visual feedback.

An experimental study was conducted to determine the effects of various forms of visual and force feedback on human performance for several "peg-in-hole"-type telemanipulation tasks. Each of six human test subjects used a master/slave manipulator during two experimental sessions. In one session the subjects performed the tasks with direct vision, where subtended visual angle, force feedback, task difficulty, and the interaction of subtended visual angle and force feedback made significant differences in task completion times. During the other session the tasks were performed using a video monitor for visual feedback, and video frame rate, force feedback, task difficulty, and the interaction of frame rate and force feedback were found to make significant differences in task times. An analysis between the direct and video viewing environments showed that apart from subtended visual angle and reduced frame rate, the video medium itself did not significantly affect task times relative to direct viewing.

Artificial Intelligence↗

Virtual environments.

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Artificial Intelligence↗