Preferred VDT workstation settings, body posture and physical impairments

In a field study an adjustable VDT workstation was given to each of the 68 operators for one week. The preferred settings, the body postures and subjective evaluations were assessed during normal working activities of the operators. The preferred ranges disclose the following figures: keyboard height (home row above floor) 71-87 cm, screen height (centre above floor) 92-116 cm, viewing angles (eye to screen centre) + 2 to -26 degrees, visual distance (eye to screen) 61-93 cm. There was practically no correlation between preferred settings and anthropometric data of body length or eye levels above floor. The study of body postures revealed that the great majority of operators tend to lean backwards with trunk inclinations between 97 degrees and 121 degrees (95% confidence interval). Some of the preferred settings strongly differ from those recommended in many brochures and standards. The physical complaints in the neck-shoulder and back area are diminished with the preferred settings.     

Tactile recognition and localization using object models: the case of polyhedra on a plane

This paper discusses how data from multiple tactile sensors may be used to identify and locate one object, from among a set of known objects. We use only local information from sensors: 1) the position of contact points and 2) ranges of surface normals at the contact points. The recognition and localization process is structured as the development and pruning of a tree of consistent hypotheses about pairings between contact points and object surfaces. In this paper, we deal with polyhedral objects constrained to lie on a known plane, i.e., having three degrees of positioning freedom relative to the sensors. We illustrate the performance of the algorithm by simulation.     

EMERGE-A Data-Driven Medical Decision Making Aid

EMERGE is an expert system designed as a medical decision making aid. It is machine-independent, and is implemented in standard Pascal. It has modest memory requirements, and can operate on a microcomputer. EMERGE is rule-based, and its initial application is the analysis of chest pain in the emergency room. The knowledge base is maintained separately from the consultation program. Thus the application area can be changed without any modification to the software. This paper describes the control structures and rule searching procedures used in EMERGE.     

Psychomotor performance: the effects of continuous noise and augmented feedback

An experiment is reported which tests the hypothesis, put forward by Poulton (1976a, b) that the detrimental effects of noise are due to the masking of auditory feedback. The results of the experiment showed that noise impaired the performance of a tracking task both in the presence and absence of task-related auditory feedback. These findings are contrary to Poulton's predictions.     

Ergonomics in the design and evaluation of a system for "postal video letter coding"

In co-operation with the German Central Post Office for Technological Development, the authors designed and investigated the task of and workplace for "Postal video-letter-coding". Experiments including measures of performance, errors, heart rate, arrhythmia, EMG's, and EOG's were used to experiment with variations in the design of displays, codes, keyboards, shifts and rest pauses. As a result of this work the following recommendations have been made by the authors and accepted by the authorities: An optimal display configuration has been developed with two vertically arranged tv displays. Coding-rules are to be simplified by modifications of the postcode. The usual flat keyboard has been replaced by an inclined and angular keyboard. Night-shifts must be avoided because of the tedious nature of the task. A work-rest-schedule of 50 min work and 10 min rest is proposed. In 1978 the complete work-system-design will be introduced in the standard postal service.