The LIMSI ARISE system provides vocal access by telephone to rail travel information for main French intercity connections, including timetables, simulated fares and reservations, reductions and services. Our goal is to obtain high dialog success rates with a very open interaction, where the user is free to ask any question or to provide any information at any point in time. In order to improve performance with such an open dialog strategy, we make use of implicit confirmation using the callers wording (when possible), and change to a more constrained dialog level when the dialog is not going well.

This article describes approaches to content-based access to spoken audio with a qualitative and tutorial emphasis. We describe how the analysis, retrieval and delivery phases contribute making spoken audio content more accessible, and we outline a number of outstanding research issues. We also discuss the main application domains and try to identify important issues for future developments. The structure of the article is based on general system architecture for content-based 2 access which is depicted in Figure 1. Although the tasks within each processing stage may appear unconnected, the interdependencies and the sequence with which they take place vary

The development of natural spoken language dialog systems requires expertise in multiple domains, including speech recognition, natural spoken language understanding and generation, dialog managment and speech synthesis. In this paper I report on our experience at LIMSI in the design, development and evaluation of spoken language dialog systems for information retrieval tasks. Drawing upon our experience in this area, I attempt to highlight some aspects of the design process, such as the use of general and task-specific knowledge sources, the need for an iterative development cycle, and some of the difficulties related to evaluation of development progress. 1. INTRODUCTION At LIMSI we have experience in developing several spoken language dialog systems for information retrieval tasks[5, 11, 16, 19, 1]. Our recent activities in this area have been mainly in the context of European projects, such as ESPRIT MASK, Language Engineering RAILTEL and ARISE, Tide HOME-AOM, Esprit LTR Concerte...

: This paper summarizes recent activities at LIMSI in multilingual speech recognition and its applications. While the main goal of speech recognition is to provide a transcription of the speech signal as a sequence of words, the same basic technology serves as the first step in other application areas, such as in automatic systems for information access and for automatic indexation of audiovisual data. SPEECH RECOGNITION Speech recognition is principally concerned with the problem of transcribing the speech signal as a sequence of words. The LIMSI system, in common with most of today's state-of-the-art systems (4), makes use of statistical models of speech generation. From this point of view, message generation is represented by a language model which provides an estimate of the probability of any given word string, and the encoding of the message in the acoustic signal is represented by a probability density function (HMM). The speech decoding problem then consists of maximizing the...

In this paper we report on a series of user trials carried out to assess the performance and usability of the Multimodal Multimedia Service Kiosk (MASK) prototype kiosk. The aim of the ESPRIT MASK project was to pave the way for advanced public service applications with user interfaces employing multimodal, multi-media input and output. The prototype kiosk was developed after analyzing the technological requirements in the context of users performing travel enquiry tasks, in close collaboration with the French Railways (SNCF) and the Ergonomics group at the University College of London (UCL). The time to complete the transaction with the MASK kiosk is reduced by about 30% compared to that required for the standard kiosk, and the success rate is 85% for novices and 94% once familiar with the system. In addition to meeting or exceeding the performance goals set at the project onset in terms of success rate, transaction time, and user satisfaction, the MASK kiosk was judged to be user-friendly and simple to use.

Abstract. Virtual worlds are developing rapidly over the Internet. They are visited by avatars and staffed with Embodied Conversational Agents (ECAs). An avatar is a representation of a physical person. Each person controls one or several avatars and usually receives feedback from the virtual world on an audio-visual display. Ideally, all senses should be used to feel fully embedded in a virtual world. Sound, vision and sometimes touch are the available modalities. This paper reviews the technological developments which enable audio-visual interactions in virtual and augmented reality worlds. Emphasis is placed on speech and gesture interfaces, including talking face analysis and synthesis.