ASSESSING HUMAN PERCEPTION

Network technology typically contains complex and nonlinear processes, such as low bit rate codes for data reduction. This nonlinearity mean s that the perceived performance cannot be predicted with conventional engineering performance metrics. Reliable objective assessment of per ceived performance is required for optimal design, commissioning and m onitoring of quality. This paper looks at how BT can measure, optimise and control the perceived performance of the service that is provided . The final receiver of a signal is the human user - by modelling the senses of the human it is possible to predict whether an error would b e perceptible. An auditory perceptual model has been developed and use d to predict the subjective performance of a variety of nonlinear syst ems. Applications for the auditory model include design optimisation, measurement tool and as part of a nonlinear network planning tool. Thi s paper focuses specifically on the auditory system, and how perceptua l modelling is providing the basis for improved quality of voice servi ce. However, as the global landscape adapts over the next decade, with multimedia, personal interactivity, and the concept of 'virtuality' t hen all of the human senses need to be considered together. Future wor k is planned to include an elementary visual model and the combination of sensory models for the assessment of multimedia products and servi ces.