Combining Several ASR Outputs in a Graph-Based SLU System

The final publication is available at Springer via http://dx.doi.org/10.1007/978-3-319-25751-8_66In this paper, we present an approach to Spoken Language Understanding (SLU) where we perform a combination of multiple hypotheses from several Automatic Speech Recognizers (ASRs) in order to reduce the impact of recognition errors in the SLU module. This combination is performed using a Grammatical Inference algorithm that provides a generalization of the input sentences by means of a weighted graph of words. We have also developed a specific SLU algorithm that is able to process these graphs of words according to a stochastic semantic modelling.The results show that the combinations of several hypotheses from the ASR module outperform the results obtained by taking just the 1-best transcriptionThis work is partially supported by the Spanish MEC under contract TIN2014-54288-C4-3-R and FPU Grant AP2010-4193.Calvo Lance, M.; Hurtado Oliver, LF.; García-Granada, F.; Sanchís Arnal, E. (2015). Combining Several ASR Outputs in a Graph-Based SLU System. En Progress in Pattern Recognition, Image Analysis, Computer Vision, and Applications. Springer. 551-558. https://doi.org/10.1007/978-3-319-25751-8_66S551558Bangalore, S., Bordel, G., Riccardi, G.: Computing consensus translation from multiple machine translation systems. In: ASRU, pp. 351–354 (2001)Benedí, J.M., Lleida, E., Varona, A., Castro, M.J., Galiano, I., Justo, R., de Letona, I.L., Miguel, A.: Design and acquisition of a telephone spontaneous speech dialogue corpus in Spanish: DIHANA. In: LREC, pp. 1636–1639 (2006)Bonneau-Maynard, H., Lefèvre, F.: Investigating stochastic speech understanding. In: IEEE Automatic Speech Recognition and Understanding Workshop (ASRU), pp. 260–263 (2001)Calvo, M., García, F., Hurtado, L.F., Jiménez, S., Sanchis, E.: Exploiting multiple hypotheses for multilingual spoken language understanding. In: CoNLL, pp. 193–201 (2013)Fiscus, J.G.: A post-processing system to yield reduced word error rates: recognizer output voting error reduction (ROVER). In: 1997 IEEE Workshop on Automatic Speech Recognition and Understanding, pp. 347–354 (1997)Hahn, S., Dinarelli, M., Raymond, C., Lefèvre, F., Lehnen, P., De Mori, R., Moschitti, A., Ney, H., Riccardi, G.: Comparing stochastic approaches to spoken language understanding in multiple languages. IEEE Transactions on Audio, Speech, and Language Processing 6(99), 1569–1583 (2010)Hakkani-Tür, D., Béchet, F., Riccardi, G., Tür, G.: Beyond ASR 1-best: Using word confusion networks in spoken language understanding. Computer Speech & Language 20(4), 495–514 (2006)He, Y., Young, S.: Spoken language understanding using the hidden vector state model. Speech Communication 48, 262–275 (2006)Larkin, M.A., Blackshields, G., Brown, N.P., Chenna, R., McGettigan, P.A., McWilliam, H., Valentin, F., Wallace, I.M., Wilm, A., Lopez, R., Thompson, J.D., Gibson, T.J., Higgins, D.G.: ClustalW and ClustalX version 2.0. Bioinformatics 23(21), 2947–2948 (2007)Segarra, E., Sanchis, E., Galiano, M., García, F., Hurtado, L.: Extracting Semantic Information Through Automatic Learning Techniques. IJPRAI 16(3), 301–307 (2002)Tür, G., Deoras, A., Hakkani-Tür, D.: Semantic parsing using word confusion networks with conditional random fields. In: INTERSPEECH (2013

Verbmobil : translation of face-to-face dialogs

Verbmobil is a long-term project on the translation of spontaneous language in negotiation dialogs. We describe the goals of the project, the chosen discourse domains and the initial project schedule. We discuss some of the distinguishing features of Verbmobil and introduce the notion of translation on demand and variable depth of processing in speech translation. Finally, the role of anytime modules for efficient dialog translation in close to real time is described

Exploiting multiple ASR outputs for a spoken language understanding task

The final publication is available at Springer via http://dx.doi.org/10.1007/978-3-319-01931-4_19In this paper, we present an approach to Spoken Language Understanding, where the input to the semantic decoding process is a composition of multiple hypotheses provided by the Automatic Speech Recognition module. This way, the semantic constraints can be applied not only to a unique hypothesis, but also to other hypotheses that could represent a better recognition of the utterance. To do this, we have developed an algorithm to combine multiple sentences into a weighted graph of words, which is the input to the semantic decoding process. It has also been necessary to develop a specific algorithm to process these graphs of words according to the statistical models that represent the semantics of the task. This approach has been evaluated in a SLU task in Spanish. Results, considering different configurations of ASR outputs, show the better behavior of the system when a combination of hypotheses is considered.This work is partially supported by the Spanish MICINN under contract TIN2011-28169-C05-01, and under FPU Grant AP2010-4193Calvo Lance, M.; García Granada, F.; Hurtado Oliver, LF.; Jiménez Serrano, S.; Sanchís Arnal, E. (2013). Exploiting multiple ASR outputs for a spoken language understanding task. En Speech and Computer. Springer Verlag (Germany). 8113:138-145. https://doi.org/10.1007/978-3-319-01931-4_19S1381458113Tür, G., Mori, R.D.: Spoken Language Understanding: Systems for Extracting Semantic Information from Speech, 1st edn. Wiley (2011)Fiscus, J.G.: A post-processing system to yield reduced word error rates: Recognizer output voting error reduction (ROVER). In: Proceedings of the 1997 IEEE Workshop on Automatic Speech Recognition and Understanding, pp. 347–354. IEEE (1997)Larkin, M.A., Blackshields, G., Brown, N.P., Chenna, R., McGettigan, P.A., McWilliam, H., Valentin, F., Wallace, I.M., Wilm, A., Lopez, R., Thompson, J.D., Gibson, T.J., Higgins, D.G.: ClustalW and ClustalX version 2.0. Bioinformatics 23, 2947–2948 (2007)Sim, K.C., Byrne, W.J., Gales, M.J.F., Sahbi, H., Woodland, P.C.: Consensus network decoding for statistical machine translation system combination. In: IEEE Int. Conference on Acoustics, Speech, and Signal Processing (2007)Bangalore, S., Bordel, G., Riccardi, G.: Computing Consensus Translation from Multiple Machine Translation Systems. In: Proceedings of IEEE Automatic Speech Recognition and Understanding Workshop (ASRU 2001), pp. 351–354 (2001)Calvo, M., Hurtado, L.-F., García, F., Sanchís, E.: A Multilingual SLU System Based on Semantic Decoding of Graphs of Words. In: Torre Toledano, D., Ortega Giménez, A., Teixeira, A., González Rodríguez, J., Hernández Gómez, L., San Segundo Hernández, R., Ramos Castro, D. (eds.) IberSPEECH 2012. CCIS, vol. 328, pp. 158–167. Springer, Heidelberg (2012)Hakkani-Tür, D., Béchet, F., Riccardi, G., Tür, G.: Beyond ASR 1-best: Using word confusion networks in spoken language understanding. Computer Speech & Language 20, 495–514 (2006)Benedí, J.M., Lleida, E., Varona, A., Castro, M.J., Galiano, I., Justo, R., López de Letona, I., Miguel, A.: Design and acquisition of a telephone spontaneous speech dialogue corpus in Spanish: DIHANA. In: Proceedings of LREC 2006, Genoa, Italy, pp. 1636–1639 (2006

Soft Computing Models for the Development of Commercial Conversational Agents

Proceedings of: 6th International Conference on Soft Computing Models in Industrial and Environmental Applications (SOCO 2011). Salamanca, April 6-8, 2011In this paper we present a proposal for the development of conversational agents that, on the one hand, takes into account the benefits of using standards like VoiceXML, whilst on the other, includes a module with a soft computing model that avoids the effort of manually defining the dialog strategy. This module is trained using a labeled dialog corpus, and selects the next system response considering a classification process based on neural networks that takes into account the dialog history. Thus, system developers only need to define a set of VoiceXML files, each including a system prompt and the associated grammar to recognize the users responses to the prompt. We have applied this technique to develop a conversational agent in VoiceXML that provides railway information in Spanish.Funded by projects CICYT TIN2008-06742-C02-02/TSI, CICYT TEC2008-06732-C02- 02/TEC, CAM CONTEXTS (S2009/TIC-1485), and DPS2008-07029-C02-02.Publicad

Research on speech understanding and related areas at SRI

Research capabilities on speech understanding, speech recognition, and voice control are described. Research activities and the activities which involve text input rather than speech are discussed

Exploiting Deep Semantics and Compositionality of Natural Language for Human-Robot-Interaction

We develop a natural language interface for human robot interaction that implements reasoning about deep semantics in natural language. To realize the required deep analysis, we employ methods from cognitive linguistics, namely the modular and compositional framework of Embodied Construction Grammar (ECG) [Feldman, 2009]. Using ECG, robots are able to solve fine-grained reference resolution problems and other issues related to deep semantics and compositionality of natural language. This also includes verbal interaction with humans to clarify commands and queries that are too ambiguous to be executed safely. We implement our NLU framework as a ROS package and present proof-of-concept scenarios with different robots, as well as a survey on the state of the art

Lyrebird [TM]: Developing Spoken Dialog Systems Using Examples

An early release software product for the rapid development of spoken dialog systems SDS's), known as Lyrebird [TM] [1][2][3], will be demonstrated that makes use of grammatical inference to build natural language, mixed initiative, speech recognition applications. The demonstration will consist of the presenter developing a spoken dialog system using Lyrebird [TM], and will include a demonstration of some features that are still in the prototype phase

A Strategy for Multilingual Spoken Language Understanding Based on Graphs of Linguistic Units

[EN] In this thesis, the problem of multilingual spoken language understanding is addressed using graphs to model and combine the different knowledge sources that take part in the understanding process. As a result of this work, a full multilingual spoken language understanding system has been developed, in which statistical models and graphs of linguistic units are used. One key feature of this system is its ability to combine and process multiple inputs provided by one or more sources such as speech recognizers or machine translators. A graph-based monolingual spoken language understanding system was developed as a starting point. The input to this system is a set of sentences that is provided by one or more speech recognition systems. First, these sentences are combined by means of a grammatical inference algorithm in order to build a graph of words. Next, the graph of words is processed to construct a graph of concepts by using a dynamic programming algorithm that identifies the lexical structures that represent the different concepts of the task. Finally, the graph of concepts is used to build the best sequence of concepts. The multilingual case happens when the user speaks a language different to the one natively supported by the system. In this thesis, a test-on-source approach was followed. This means that the input sentences are translated into the system's language, and then they are processed by the monolingual system. For this purpose, two speech translation systems were developed. The output of these speech translation systems are graphs of words that are then processed by the monolingual graph-based spoken language understanding system. Both in the monolingual case and in the multilingual case, the experimental results show that a combination of several inputs allows to improve the results obtained with a single input. In fact, this approach outperforms the current state of the art in many cases when several inputs are combined.[ES] En esta tesis se aborda el problema de la comprensión multilingüe del habla utilizando grafos para modelizar y combinar las diversas fuentes de conocimiento que intervienen en el proceso. Como resultado se ha desarrollado un sistema completo de comprensión multilingüe que utiliza modelos estadísticos y grafos de unidades lingüísticas. El punto fuerte de este sistema es su capacidad para combinar y procesar múltiples entradas proporcionadas por una o varias fuentes, como reconocedores de habla o traductores automáticos. Como punto de partida se desarrolló un sistema de comprensión multilingüe basado en grafos. La entrada a este sistema es un conjunto de frases obtenido a partir de uno o varios reconocedores de habla. En primer lugar, se aplica un algoritmo de inferencia gramatical que combina estas frases y obtiene un grafo de palabras. A continuación, se analiza el grafo de palabras mediante un algoritmo de programación dinámica que identifica las estructuras léxicas correspondientes a los distintos conceptos de la tarea, de forma que se construye un grafo de conceptos. Finalmente, se procesa el grafo de conceptos para encontrar la mejo secuencia de conceptos. El caso multilingüe ocurre cuando el usuario habla una lengua distinta a la original del sistema. En este trabajo se ha utilizado una estrategia test-on-source, en la cual las frases de entrada se traducen al lenguaje del sistema y éste las trata de forma monolingüe. Para ello se han propuesto dos sistemas de traducción del habla cuya salida son grafos de palabras, los cuales son procesados por el algoritmo de comprensión basado en grafos. Tanto en la configuración monolingüe como en la multilingüe los resultados muestran que la combinación de varias entradas permite mejorar los resultados obtenidos con una sola entrada. De hecho, esta aproximación consigue en muchos casos mejores resultados que el actual estado del arte cuando se utiliza una combinación de varias entradas.[CA] Aquesta tesi tracta el problema de la comprensió multilingüe de la parla utilitzant grafs per a modelitzar i combinar les diverses fonts de coneixement que intervenen en el procés. Com a resultat s'ha desenvolupat un sistema complet de comprensió multilingüe de la parla que utilitza models estadístics i grafs d'unitats lingüístiques. El punt fort d'aquest sistema és la seua capacitat per combinar i processar múltiples entrades proporcionades per una o diverses fonts, com reconeixedors de la parla o traductors automàtics. Com a punt de partida, es va desenvolupar un sistema de comprensió monolingüe basat en grafs. L'entrada d'aquest sistema és un conjunt de frases obtingut a partir d'un o més reconeixedors de la parla. En primer lloc, s'aplica un algorisme d'inferència gramatical que combina aquestes frases i obté un graf de paraules. A continuació, s'analitza el graf de paraules mitjançant un algorisme de programació dinàmica que identifica les estructures lèxiques corresponents als distints conceptes de la tasca, de forma que es construeix un graf de conceptes. Finalment, es processa aquest graf de conceptes per trobar la millor seqüència de conceptes. El cas multilingüe ocorre quan l'usuari parla una llengua diferent a l'original del sistema. En aquest treball s'ha utilitzat una estratègia test-on-source, en la qual les frases d'entrada es tradueixen a la llengua del sistema, i aquest les tracta de forma monolingüe. Per a fer-ho es proposen dos sistemes de traducció de la parla l'eixida dels quals són grafs de paraules. Aquests grafs són posteriorment processats per l'algorisme de comprensió basat en grafs. Tant per la configuració monolingüe com per la multilingüe els resultats mostren que la combinació de diverses entrades és capaç de millorar el resultats obtinguts utilitzant una sola entrada. De fet, aquesta aproximació aconsegueix en molts casos millors resultats que l'actual estat de l'art quan s'utilitza una combinació de diverses entrades.Calvo Lance, M. (2016). A Strategy for Multilingual Spoken Language Understanding Based on Graphs of Linguistic Units [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/62407TESI

Analysis and Design of Speech-Recognition Grammars

Currently, most commercial speech-enabled products are constructed using grammar-based technology. Grammar design is a critical issue for good recognition accuracy. Two methods are commonly used for creating grammars: 1) to generate them automatically from a large corpus of input data which is very costly to acquire, or 2) to construct them using an iterative process involving manual design, followed by testing with end-user speech input. This is a time-consuming and very expensive process requiring expert knowledge of language design, as well as the application area. Another hurdle to the creation and use of speech-enabled applications is that expertise is also required to integrate the speech capability with the application code and to deploy the application for wide-scale use. An alternative approach, which we propose, is 1) to construct them using the iterative process described above, but to replace end-user testing by analysis of the recognition grammars using a set of grammar metrics which have been shown to be good indicators of recognition accuracy, 2) to improve recognition accuracy in the design process by encoding semantic constraints in the syntax rules of the grammar, 3) to augment the above process by generating recognition grammars automatically from specifications of the application, and 4) to use tools for creating speech-enabled applications together with an architecture for their deployment which enables expert users, as well as users who do not have expertise in language processing, to easily build speech applications and add them to the web