Biomedical subjects

D B Kaber

Publications and source records attributed to D B Kaber.

4 recordsLinked to original sources

PubMed2000

A new approach to applying feedforward neural networks to the prediction of musculoskeletal disorder risk.

A new and improved method to feedforward neural network (FNN) development for application to data classification problems, such as the prediction of levels of low-back disorder (LBD) risk associated with industrial jobs, is presented. Background on FNN development for data classification is provided along with discussions of previous research and neighborhood (local) solution search methods for hard combinatorial problems. An analytical study is presented which compared prediction accuracy of a FNN based on an error-back propagation (EBP) algorithm with the accuracy of a FNN developed by considering results of local solution search (simulated annealing) for classifying industrial jobs as posing low or high risk for LBDs. The comparison demonstrated superior performance of the FNN generated using the new method. The architecture of this FNN included fewer input (predictor) variables and hidden neurons than the FNN developed based on the EBP algorithm. Independent variable selection methods and the phenomenon of 'overfitting' in FNN (and statistical model) generation for data classification are discussed. The results are supportive of the use of the new approach to FNN development for applications to musculoskeletal disorders and risk forecasting in other domains.

Back Injuries↗

PubMed1999

Level of automation effects on performance, situation awareness and workload in a dynamic control task.

Various levels of automation (LOA) designating the degree of human operator and computer control were explored within the context of a dynamic control task as a means of improving overall human/machine performance. Automated systems have traditionally been explored as binary function allocations; either the human or the machine is assigned to a given task. More recently, intermediary levels of automation have been discussed as a means of maintaining operator involvement in system performance, leading to improvements in situation awareness and reductions in out-of-the-loop performance problems. A LOA taxonomy applicable to a wide range of psychomotor and cognitive tasks is presented here. The taxonomy comprises various schemes of generic control system function allocations. The functions allocated to a human operator and/or computer included monitoring displays, generating processing options, selecting an 'optimal' option and implementing that option. The impact of the LOA taxonomy was assessed within a dynamic and complex cognitive control task by measuring its effect on human/system performance, situation awareness and workload. Thirty subjects performed simulation trials involving various levels of automation. Several automation failures occurred and out-of-the-loop performance decrements were assessed. Results suggest that, in terms of performance, human operators benefit most from automation of the implementation portion of the task, but only under normal operating conditions; in contrast, removal of the operator from task implementation is detrimental to performance recovery if the automated system fails. Joint human/system option generation significantly degraded performance in comparison to human or automated option generation alone. Lower operator workload and higher situation awareness were observed under automation of the decision making portion of the task (i.e. selection of options), although human/system performance was only slightly improved. The implications of these findings for the design of automated systems are discussed.

Adult↗

PubMed1998

Telepresence.

Telepresence, the perception of presence within a physically remote or simulated site, has been identified as a design ideal for synthetic environments. However, confusion exists within the literature about the precise definition of telepresence. Furthermore, there is a need for a plausible and parsimonious model of telepresence. This paper identifies three types of telepresence extant in the literature: simple telepresence, cybernetic telepresence, and experiential telepresence. The third definition is the most interesting. This paper reviews the origins of experiential telepresence and the theoretical approaches commonly used to explain it. One can term these technological approaches, which emphasize the role of control/display technology, and psychological approaches, which identify experiential telepresence with known psychological phenomena. Finally, the paper presents and discusses an integrative approach to telepresence featuring a structured attentional resource model. Actual or potential applications of this research include the design of future human-machine interfaces for teleoperated robots and virtual reality systems.

Cybernetics↗

PubMed1998

The effect of automated compensation for incongruent axes on teleoperator performance.

Teleoperation is frequently performed with misalignments between operator or camera viewing direction and controller orientation. Examples of this occur in endoscopic surgery and in teleoperation with multiple camera views. The objective of this study was to find a method to automatically compensate for those misalignments so that human operators performing tasks under such scenarios could achieve levels of performance comparable to aligned conditions without additional training requirements. In this paper we report on a set of experiments conducted to test a method developed for that purpose. Participants were asked to track a randomly moving target on a computer display using a cursor controlled with a joystick. Performance was recorded under various visual-motor misalignments with and without automated compensation. Results indicated significant improvements in operator performance through use of automatic compensation only under certain types of misalignment. Actual or potential applications of this research include teleoperation and endoscopic surgery.

Data Display↗