Klaus-Peter Engelbrecht

Learn More
Models for predicting judgments about the quality of Spoken Dialog Systems have been used as overall evaluation metric or as optimization functions in adaptive systems. We describe a new approach to such models, using Hidden Markov Models (HMMs). The user’s opinion is regarded as a continuous process evolving over time. We present the data collection method(More)
Communication failures are typical for interactions with spoken dialogue systems, in particular when dialogues get less structured and less foreseeable. In this paper, we adopt a new classification scheme of communication failures and their consequences and show its usefulness in three respects: (1) For the systematic analysis of data collected in user(More)
Proper usability evaluations of spoken dialogue systems are costly and cumbersome to carry out. In this paper, we present a new approach for facilitating usability evaluations which is based on user error simulations. The idea is to replace real users with simulations derived from empirical observations of users’ erroneous behavior. The simulated errors(More)
Emotion plays an important role in human communication and therefore also human machine dialog systems can benefit from affective processing. We present in this paper an overview of our work from the past few years and discuss general considerations, potential applications and experiments that we did with the emotional classification of human machine(More)
Quality of Service (QoS) and Quality of Experience (QoE) have to be considered when designing, building and maintaining services involving multimodal human–machine interaction. In order to guide the assessment and evaluation of such services, we first develop a taxonomy of the most relevant QoS and QoE aspects which result from multimodal human–machine(More)
In this paper we present a new approach to the automation of usability evaluation for interactive systems. Design ideas or complete systems are modeled as a conditional state machine. Then, user interactions with the system are simulated on the basis of tasks, by first searching for possible solution paths and then generating deviations from these paths(More)
It is well known that help prompts shape how users talk to spoken dialogue systems. This study investigated the effect of help prompt placement on older users’ interaction with a smart home interface. In the dynamic help condition, help was only given in response to system errors; in the inherent help condition, it was also given at the start of each task.(More)