Jacques M. B. Terken

Deaccentuation of Words Representing ‘Given’ Information: Effects of Persistence of Grammatical Function and Surface Position

The absence of intonational prominence on a referring expression (deaccentuation) is commonly explained as a consequence of the GIVENness of the discourse entity referred to - the fact that it represents old information in the discourse. However, speakers sometimes use accented expressions to refer to such GIVEN entities, so that GIVENness is not a sufficient explanation for deaccentuation. It has also been suggested that speakers tend to express GIVEN entities as grammatical subjects and to mention them early in the utterance. The present work investigates the contributions of grammatical role and surface position to the occurrence of deaccentuation in English. An experiment is reported in which speakers produced descriptions of visual materials, where the content of the materials was manipulated so that successive descriptions contained coreferential expressions, and grammatical role and surface position varied systematically. The results indicate that persistence of grammatical role and surface position from one utterance to the next both contribute to deaccentuation. Some implications for the way in which listeners may link referring expressions to entities which are already available from the context are discussed.

User-centred design and evaluation of ubiquitous services

Theoretical and technological progress has revived the interest in the design of services for the support of co-located human-human communication and collaboration, witnessing the start of several large-scale projects over the last few years. Most of these projects focus on meetings and/or lecture situations. However, user-centred design and evaluation frameworks for co-located communication and collaboration are a major concern. In this paper, we summarise the prevalent approaches towards user-centred design and evaluation, and we develop two different services. In one service, participants in a small-group meeting receive real-time feedback about observable properties of the meeting that are directly related to the social dynamics, such as individual amount of speaking time or eye-gaze patterns. In the other service, teachers in a classroom receive real-time feedback about the activities and attention level of participants in the lecture. We also propose ways to address the different dimensions that are relevant to the design and evaluation of these services (the individual, the social and the organisational dimension), bringing together methods from different disciplines.

Prosodic realizations of global and local structure and rhetorical relations in read aloud news reports

The aim of this research is to study effects of global and local structure of texts and of rhetorical relations between sentences on the prosodic realization of sentences in read aloud text. Twenty texts were analyzed using Rhetorical Structure Theory. Based on these analyses, the global structure in terms of hierarchical level, the local structure in terms of the relative importance of text segments and the rhetorical relations between text segments were identified. The texts were read aloud. Pause durations preceding segments, F0-maxima and articulation rates of the segments were measured. It was found that speakers give prosodic indications about hierarchical level by means of variations in pause duration and pitch range: the higher the segments are connected in the text structure, the longer the preceding pauses and the higher the F0-maxima are realized. Also, it was found that speakers articulate important segments more slowly than unimportant segments, and that they read aloud causally related segments with shorter in-between pauses and at faster rate than non-causally related segments. We conclude that variation in pause duration and F0-maximum is a robust means for speakers to express the global structure of texts, although this does not apply to all speakers. Speakers also vary pause duration and articulation rate to indicate importance of sentences and meaning relations between sentences.

Synthesizing natural-sounding intonation for Dutch: rules and perceptual evaluation

An algorithm is described for synthesizing intonation in the absence of syntactic information as part of an experimental system for text-to-speech conversion for Dutch. It contains several improvements of an existing algorithm. The improvements are based on analyses of speech data collected from a professional reader. They mainly concern the intonational realization of intonation phrases. The performance of the algorithm has been evaluated in a perceptual test, in which listeners were asked to judge the naturalness of the intonation. For isolated utterances, the rule-based intonation is judged more natural than the intonation generated with the older algorithm, and as natural as the human intonation. For coherent text, the rule-based intonation is judged more natural than the intonation generated with the older algorithm, but less natural than the human intonation. These findings suggest that the decomposition of the utterance into intonation phrases by means of pitch makes an essential contribution to the naturalness of synthetic speech. In addition, they support earlier findings, reported in the literature, which point to the perceptual relevance of text intonation.

Co-constructing stories: a participatory design technique to elicit in-depth user feedback and suggestions about design concepts

In this paper we introduce a participatory design technique for early, formative concept evaluations to elicit in-depth user feedback and suggestions, revealing attitudes and motivations of users. The technique is motivated by the link between memories, experiences and dreams, and is based on the assumption that users can make better judgments about novel design concepts if they link them to their past experiences. The technique involves user sessions consisting of two main phases, one focusing on recollecting past experiences in related contexts, and one focusing on envisioning future experiences that can be enabled by the use of the concept. In both phases, designer-user dialogue is established through storytelling. Storytelling is used by the designer to set the stage and to present the concept and by the user to communicate his past and anticipated future experiences. The technique results in joint stories about novel concepts. In this paper we explain the technique in detail. We discuss its theoretical background and relation to other user research methods. We share the insights that we gathered through first pilots. The paper concludes with a discussion about the use of this technique in the design process and future research.

Effects of speech-based vs handheld e-mailing and texting on driving performance and experience

In this paper we present a voice-enabled service for handling e-mail and SMS messages while driving, and an evaluation of the service. In the evaluation, driving performance was compared in three conditions with a highway driving scenario in a driving simulator: driving only, driving in combination with voice-enabled handling of e-mail/SMS messages, and driving in combination with handheld handling of e-mail/SMS messages. Both objective measurements and subjective judgments about driving performance were collected. The results showed that drivers increased the headway when performing an additional task. With respect to the subjective measures, drivers felt that driving only was safest, and that voice-enabled interaction was safer, enabled better concentration and a better driving performance than handheld interaction. We conclude that handheld interaction is felt to have a stronger impact on driver performance and workload than voice-enabled interaction.

Investigating the relationship between the personality of a robotic TV assistant and the level of user control

This paper describes the design and evaluation of a robotic TV assistant that helps users find a TV-programme that fits their interests. Questions that were addressed include: What personality do users prefer for the robotic TV-assistant? What level of control do they prefer? How do personality and the level of control relate to each other? Four prototypes were developed by combining two personalities and two levels of user control. In the high control condition, a speech-based command-and-control interaction style was used, whereas the interaction style in the low control condition consisted of speech-based system-initiative natural language dialogue. The results demonstrated an interaction between the effects of personality and level of control on user preferences. Overall, the most preferred combination was an extravert and friendly personality with low user control. Additionally, it was found that perceived level of control was influenced by the robots personality. This suggests that the robots personality can be used as a means to increase the amount of control that users perceive

Rules of conduct for autonomous vehicles

When developing autonomous vehicles, we should not only focus on technology development but also think about what behaviour to program into such vehicles. This paper addresses the question of whether we should enable users to influence the politeness of autonomous vehicles. A survey was conducted with 58 participants to probe peoples willingness to display polite traffic behaviour. Scenarios were shown to people in which the weather conditions and the vulnerability of road users were manipulated, and people were asked to indicate whether they would give right of way or not. It was found that the willingness to give right of way was influenced by the weather conditions, the vulnerability of road users and the driving style of the participants. We conclude that traffic politeness varies across people and situations, and that this finding raises concerns for a development where autonomous vehicles are equipped with a standard uniform behaviour.

The Exploration of Autonomous Vehicle Driving Styles: Preferred Longitudinal, Lateral, and Vertical Accelerations

This paper describes a new approach in exploring preferred driving styles for autonomous vehicles through simulation of autonomous driving in real road conditions. A Wizard experiment with an equipped car was conducted to investigate the preferences of people with different driving styles, assertive and defensive, for three autonomous vehicle driving styles (defensive, assertive and light rail transit), inducing different acceleration forces, at three different road profiles. Subjective and objective measurements were collected. The results show that the defensive driving style was preferred and there were variations between participants related to their own driving style. The results indicate that the preferences of assertive drivers for the driving style of an autonomous vehicle may not match their own driving style. Yet, users of future autonomous vehicles should be able to indicate and adjust the driving behaviour of an autonomous vehicle to their own preferences in order to maximize comfort in travelling experience.

On the development of electronic design tools and associated guidelines for supporting the early stages of the design process

According to the user-centred design (UCD) philosophy, users should be involved as much as possible in the different stages of the design process, to optimize the likelihood that design proposals will be appreciated by users. In this paper, first we consider some challenges and questions that are raised by this general guideline. Next, we summarize outcomes of an ongoing project that addresses the question of when and how to involve the user in the design process. We report UCD opinions and practices in industry. In addition, we present work in progress aiming to develop tools and guidelines that should support design departments in industry to develop design proposals that optimize the fit-to-context. This includes a study investigating the effects of realism and animation of concept representations on user feedback. These studies help us to get a better understanding of when and how to involve users in the design process.