A proposal for the development of adaptive spoken interfaces to access the Web

Spoken dialog systems have been proposed as a solution to facilitate a more natural human–machine interaction. In this paper, we propose a framework to model the user׳s intention during the dialog and adapt the dialog model dynamically to the user needs and preferences, thus developing more efficient, adapted, and usable spoken dialog systems. Our framework employs statistical models based on neural networks that take into account the history of the dialog up to the current dialog state in order to predict the user׳s intention and the next system response. We describe our proposal and detail its application in the Let׳s Go spoken dialog system.Work partially supported by Projects MINECO TEC2012-37832- C02-01, CICYT TEC2011-28626-C02-02, CAM CONTEXTS (S2009/ TIC-1485

Four Mode Based Dialogue Management with Modified POMDP Model

This thesis proposes a method to manage the interaction between the user and the system dynamically, through speech or text input which updates the user goals, select system actions and calculate rewards for each system response at each time-stamp. The main focus is made on the dialog manager, which decides how to continue the dialogue. We have used POMDP technique, as it maintains a belief distribution on the dialogue states based on the observations over the dialogue even in a noisy environment. Four contextual control modes are introduced in dialogue management for decision-making mechanism, and to keep track of machine behaviour for each dialogue state. The result obtained proves that our proposed framework has overcome the limitations of prior POMDP methods, and exactly understands the actual intention of the users within the available time, providing very interactive conversation between the user and the computer

An Approach for Contextual Control in Dialogue Management with Belief State Trend Analysis and Prediction

This thesis applies the theory of naturalistic decision making (NDM) in human physcology model for the study of dialogue management system in major approaches from the classical approach based upon finite state machine to most recent approach using partially observable markov decision process (POMDP). While most of the approaches use various techniques to estimate system state, POMDP-based system uses the belief state to make decisions. In addition to the state estimation POMDP provides a mechanism to model the uncertainty and allows error-recovery. However, applying Markovian over the belief-state space in the current POMDP models cause significant loss of valuable information in the dialogue history, leading to untruthful management of user\u27s intention. Also there is a need of adequate interaction with users according to their level of knowledge. To improve the performance of POMDP-based dialogue management, this thesis proposes an enabling method to allow dynamic control of dialogue management. There are three contributions made in order to achieve the dynamism which are as follows: Introduce historical belief information into the POMDP model, analyzing its trend and predicting the user belief states with history information and finally using this derived information to control the system based on the user intention by switching between contextual control modes. Theoretical derivations of proposed work and experiments with simulation provide evidence on dynamic dialogue control of the agent to improve the human-computer interaction using the proposed algorithm

Apprentissage par renforcement pour la généralisation des approches automatiques dans la conception des systèmes de dialogue oral

Les systèmes de dialogue homme machine actuellement utilisés dans l industrie sont fortement limités par une forme de communication très rigide imposant à l utilisateur de suivre la logique du concepteur du système. Cette limitation est en partie due à leur représentation de l état de dialogue sous la forme de formulaires préétablis.Pour répondre à cette difficulté, nous proposons d utiliser une représentation sémantique à structure plus riche et flexible visant à permettre à l utilisateur de formuler librement sa demande.Une deuxième difficulté qui handicape grandement les systèmes de dialogue est le fort taux d erreur du système de reconnaissance vocale. Afin de traiter ces erreurs de manière quantitative, la volonté de réaliser une planification de stratégie de dialogue en milieu incertain a conduit à utiliser des méthodes d apprentissage par renforcement telles que les processus de décision de Markov partiellement observables (POMDP). Mais un inconvénient du paradigme POMDP est sa trop grande complexité algorithmique. Certaines propositions récentes permettent de réduire la complexité du modèle. Mais elles utilisent une représentation en formulaire et ne peuvent être appliqués directement à la représentation sémantique riche que nous proposons d utiliser.Afin d appliquer le modèle POMDP dans un système dont le modèle sémantique est complexe, nous proposons une nouvelle façon de contrôler sa complexité en introduisant un nouveau paradigme : le POMDP résumé à double suivi de la croyance. Dans notre proposition, le POMDP maitre, complexe, est transformé en un POMDP résumé, plus simple. Un premier suivi de croyance (belief update) est réalisé dans l espace maitre (en intégrant des observations probabilistes sous forme de listes nbest). Et un second suivi de croyance est réalisé dans l espace résumé, les stratégies obtenues sont ainsi optimisées sur un véritable POMDP.Nous proposons deux méthodes pour définir la projection du POMDP maitre en un POMDP résumé : par des règles manuelles et par regroupement automatique par k plus proches voisins. Pour cette dernière, nous proposons d utiliser la distance d édition entre graphes, que nous généralisons pour obtenir une distance entre listes nbest.En outre, le couplage entre un système résumé, reposant sur un modèle statistique par POMDP, et un système expert, reposant sur des règles ad hoc, fournit un meilleur contrôle sur la stratégie finale. Ce manque de contrôle est en effet une des faiblesses empêchant l adoption des POMDP pour le dialogue dans l industrie.Dans le domaine du renseignement d informations touristiques et de la réservation de chambres d hôtel, les résultats sur des dialogues simulés montrent l efficacité de l approche par renforcement associée à un système de règles pour s adapter à un environnement bruité. Les tests réels sur des utilisateurs humains montrent qu un système optimisé par renforcement obtient cependant de meilleures performances sur le critère pour lequel il a été optimisé.Dialog managers (DM) in spoken dialogue systems make decisions in highly uncertain conditions, due to errors from the speech recognition and spoken language understanding (SLU) modules. In this work a framework to interface efficient probabilistic modeling for both the SLU and the DM modules is described and investigated. Thorough representation of the user semantics is inferred by the SLU in the form of a graph of frames and, complemented with some contextual information, is mapped to a summary space in which a stochastic POMDP dialogue manager can perform planning of actions taking into account the uncertainty on the current dialogue state. Tractability is ensured by the use of an intermediate summary space. Also to reduce the development cost of SDS an approach based on clustering is proposed to automatically derive the master-summary mapping function. A implementation is presented in the Media corpus domain (touristic information and hotel booking) and tested with a simulated user.AVIGNON-Bib. numérique (840079901) / SudocSudocFranceF

Dialog Systems based on Markov decision processes over two real tasks

In this work the state of the art of the automatic dialogue strategy management using Markov decision processes (MDP) with reinforcement learning (RL) is described. Partially observable Markov decision processes (POMDP) are also described. To test the validity of these methods, two spoken dialogue systems have been developed. The first one is a spoken dialogue system for weather forecast providing, and the second one is a more complex system for train information. With the first system, comparisons between a rule-based system and an automatically trained system have been done, using a real corpus to train the automatic strategy. In the second system, the scalability of these methods when used in larger systems has been tested

Discovering Dialog Rules by means of an Evolutionary Approach

Designing the rules for the dialog management process is oneof the most resources-consuming tasks when developing a dialog system. Although statistical approaches to dialog management are becoming mainstream in research and industrial contexts, still many systems are being developed following the rule-based or hybrid paradigms. For example, when developers require deterministic system responses to keep total control on the decisions made by the system, or because the infrastructure employed is designed for rule-based systems using technologies currently used in commercial platforms. In this paper, we propose the use of evolutionary algorithms to automatically obtain the dialog rules that are implicit in a dialog corpus. Our proposal makes it possible to exploit the benefits of statistical approaches to build rule-based systems. Our proposal has been evaluated with a practical spoken dialog system, for which we have automatically obtained a set of fuzzy rules to successfully manage the dialog.The research leading to these results has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 823907 (MENHIR project:https://menhir-project.eu

A BiRGAT Model for Multi-intent Spoken Language Understanding with Hierarchical Semantic Frames

Previous work on spoken language understanding (SLU) mainly focuses on single-intent settings, where each input utterance merely contains one user intent. This configuration significantly limits the surface form of user utterances and the capacity of output semantics. In this work, we first propose a Multi-Intent dataset which is collected from a realistic in-Vehicle dialogue System, called MIVS. The target semantic frame is organized in a 3-layer hierarchical structure to tackle the alignment and assignment problems in multi-intent cases. Accordingly, we devise a BiRGAT model to encode the hierarchy of ontology items, the backbone of which is a dual relational graph attention network. Coupled with the 3-way pointer-generator decoder, our method outperforms traditional sequence labeling and classification-based schemes by a large margin